Histochemistry

We studied beneficial difference of the skin of two snakes. Two snakes were chosen from two different habitats and two families: Colubridae (Natrix tessellata) and Viperidae (Cerastes vipera). The investigations were performed by light and electron microscopy. Histologically, the skin of the studied species show pronounced modifications that correlated with functional demands. The scales in Natrix tessellata overlapped slightly, while in Cerastes vipera they were highly overlapped. SEM shows that scales of Natrix tessellata had bidentate tips while the scales of Cerastes vipera were keeled. Histochemically, in both studied species, melanocytes and collagenous fibres were distributed throughout the dermis. Polysaccharides were highly concentrated in the epidermis and dermis of both species while proteins were highly concentrated only in the epidermis. Transmission electron microscopy (TEM) showed that the skin of both snakes consisted of keratins located in the epidermis. Some lipids and mucus were incorporated into the outer scale surfaces such that lipids were part of the fully keratinised hard layer of the snakes' skins. Lipids are probably responsible for limiting water loss and ion movements across the skin. Melanosomes from epidermal melanocytes were present only in Cerastes vipera. In aggregate, these results indicate that snakeskin may provide an ecological indicator whereby epidermal and integumentary specializations may be ecologically correlated.

Stereological analysis was carried out on cotyledon tissue at three different stages of germination. The tissue was selected by reference to adjacent sections which were assayed histochemically for protease activity. Day six tissue had no activity while eight and 14-day tissue did. Results show that during germination both tissue and cellular components undergo changes. The cells increase in size, the intercellular spaces increase, the cytoplasm increases in volume, the protein bodies swell and fuse, and small starch grains appear while the large starch grains do not undergo any major changes.

Based on a "field-effect" theory in colon carcinogenesis, and the expression of the disaccharide tumor marker D galactose-beta-[1-->3]-N-acetyl-D-galactosamine (Gal-GalNAc) in the rectal mucus of patients with cancer and precancer of the colon, Shamsuddin developed a simple, accurate, inexpensive, easy to perform and rapid (< or = 15 min) screening test for colonic cancer and precancerous lesions. In this study we examined 137 rectal mucus samples of randomly selected patients with colorectal malignancy or other colorectal diseases to confirm the sensitivity and specificity of this test in Croatia. Additionally, to test the validity of the "field-effect" theory, that the mucosa away from the obvious cancer will show abnormalities as a result of the generalized effect of the carcinogen throughout the entire field of the target tissue, we also monitored a subset of 53 patients post-operatively. Individuals free of colonic or any other malignancies served as c...

The cell bodies of pseudounipolar neurons in the trigeminal ganglia carry sensation from the face to the brainstem. These neurons vary in its sizes that carry specific sensations. In this study, trigeminal ganglion neurons are classified based on its sizes in to three types namely large, medium and small sized with the help of histomorphometry. Both side trigeminal ganglia showed more frequency (48%) of medium sized neurons which carry all types of sensation like pain, touch etc. The right side trigeminal ganglia showed more number of large sized neurons than left side ganglia.

Glutamine synthetase (GS) has long been known to be expressed exclusively in pericentral hepatocytes most proximal to the central veins of liver lobuli. This enzyme as well as its peculiar distribution complementary to the periportal compartment for ureogenesis plays an important role in nitrogen metabolism, particularly in homeostasis of blood levels of ammonium ions and glutamine. Despite this fact and intensive studies in vivo and in vitro, many aspects of the regulation of its activity on the protein and on the genetic level remained enigmatic. Recent experimental advances using transgenic mice and new analytic tools have revealed the fundamental role of morphogens such as wingless-type MMTV integration site family member signals (Wnt), beta-catenin, and adenomatous polyposis coli in the regulation of this particular enzyme. In addition, novel information concerning the structure of transcription factor binding sites within regulatory regions of the GS gene and their interactions with signalling pathways could be collected. In this review we focus on all aspects of the regulation of GS in the liver and demonstrate how the new findings have changed our view of the determinants of liver zonation. What appeared as a simple response of hepatocytes to blood-derived factors and local cellular interactions must now be perceived as a fundamental mechanism of adult tissue patterning by morphogens that were considered mainly as regulators of developmental processes. Though GS may be the most obvious indicator of morphogen action among many other targets, elucidation of the complex regulation of the expression of the GS gene could pave the road for a better understanding of the mechanisms involved in patterning of liver parenchyma. Based on current knowledge we propose a new concept of how morphogens, hormones and other factors may act in concert, in order to restrict gene expression to small subpopulations of one differentiated cell type, the hepatocyte, in different anatomical locations. Although many details of this regulatory network are still missing, and an era of exciting new discoveries is still about to come, it can already be envisioned that similar mechanisms may well be active in other organs contributing to the fine-tuning of organ-specific functions.

A histochemical study using fluorescein isothiocyanate (FITC)-labelled lectins to identify glycoconjugates present in the efferent ductules and the three segments of the ductus epididymis (initial, middle and terminal segment) of dogs was carried out. The lectins used were: mannose-binding lectins (Con A, LCA and PSA), galactose-binding lectins (PNA, RCA), N-acetylgalactosamine-binding lectins (DBA, SBA, SJA and GSL I), N-acetylglucosamine-binding lectins (WGA and WGAs), fucose-binding lectins (UEA) and lectins which bind to complex carbohydrate configurations (PHA E and PHA L). The lectin-binding pattern in the canine epididymis presents similarities and differences to those observed in other mammalian species. The ductuli efferentes distinctly stained with most of the lectins used, whereas in the ductus epididymis a segment specific staining pattern was observed. Whereas principal cells of the ductus epididymis stained clearly with several FITC-labelled lectins (WGA, UEA and PHA-L), basal cells showed only a significant binding of Con A.

Villin, a 95-kD cytoskeletal protein selectively expressed in the microvilli of some absorptive cells was localized immunohistochemically in the oviduct and the seminiferous excretory ducts of the mouse. Villin was found in the proximal part of the oviduct, comprising the preampulla, ampulla, and part of the isthmus. Distal to the isthmus the oviductal cells lining the junctura and the intrauterine colliculus tubaris were devoid of villin. No villin could be detected in the uterine cells. Ductuli efferentes, connecting the rete testis with the epididymis were the only portion of the male seminiferous ductal system expressing villin. The cells lining the epididymis and the vas deferens were devoid of villin. These data show that villin is selectively expressed in male and female reproductive systems and that it is limited to anatomically defined proximal portions of the reproductive ducts.

Breast cancer is a major health problem in underdeveloped countries including Sudan. Immunohistochemical typing is important for diagnosing and understanding the biology of such heterogeneous disease. To the best of our knowledge, no study has investigated the association between estrogen receptors (ER) expression and carbohydrates in breast tissue. Mammographic high density, a major risk factor, is partially attributed to carbohydrates. This study aimed to determine the type of carbohydrates in malignant and benign breast lesions and detect if there is any association between ER expression and carbohydrates using histochemical and immunohistochemical methods. A total of 60 diagnosed samples of different breast lesions were reexamined for ER status by immunohistochemistry (IHC) and for carbohydrates by histochemical staining methods i.e. periodic acid Schiff (PAS) and alcian blue. Strong relationship was discovered between ER positivity and presence of acid mucin, but not with sulfated mucin. Furthermore, strong relationship was found between ER positivity and PAS positive materials, but not with glycogen. Since there was a significant correlation between ER and carbohydrates, these positive PAS materials might be PAS positive acid mucin. These findings are useful in understanding the behavior of breast lesions. Also, these findings suggested an underlying molecular relationships and that ER expression might be predicted using histochemical demonstration of carbohydrates in female breast tissue particularly when immunohistochemistry is out of reach.

The somitomeres are spherical clusters of the paraxial mesenchymal cells. They were demonstrated only by the scanning electron microscope. No light microscopic criteria were described for the developing somitomeres. In this study the lectin binding pattern of wheat germ agglutinin and succinylated wheat germ agglutinin was used to verify the histochemical specification of the segment identity in view of the previously described scheme of somitogenesis in chick embryos. The results  showed that recruitment of the paraxial mesodermal cells is acompanied by localization of N-acetylglucosamine; organization of these cells occured in association with intracellular accumulation of sialic acid, while the segmentation of the somites was correlated with diffusion of sialic acid in the paraxial mesodermal tissue.

Intestinal metaplasia (IM) is part of a stepwise sequence of alterations of the gastric mucosa, leading ultimately to gastric cancer, and is strongly associated with chronic Helicobacter pylori infection. The molecular mechanisms underlying the onset of IM remain elusive. The aim of this study was to assess the putative involvement of two intestine-specific transcription factors, CDX1 and CDX2, in the pathogenesis of gastric IM and gastric carcinoma. Eighteen foci of IM and 46 cases of gastric carcinoma were evaluated by immunohistochemistry for CDX1 and CDX2 expression. CDX1 was expressed in all foci of IM and in 41% of gastric carcinomas; CDX2 was expressed in 17/18 foci of IM and in 54% of gastric carcinomas. In gastric carcinomas, a strong association was observed between the expression of CDX1 and CDX2, as well as between the intestinal mucin MUC2 and CDX1 and CDX2. No association was observed between the expression of CDX1 and CDX2 and the histological type of gastric carcinoma. In conclusion, these results show that aberrant expression of CDX1 and CDX2 is consistently observed in IM and in a subset of gastric carcinomas. The association of CDX1 and CDX2 with expression of the intestinal mucin MUC2, both in IM and in gastric carcinoma, indirectly implies that CDX1 and CDX2 may be involved in intestinal differentiation along the gastric carcinogenesis pathway. Copyright © 2002 John Wiley & Sons, Ltd.

S U M M A R Y Melanocytes are cells of neural crest origin. In the human epidermis, they form a close association with keratinocytes via their dendrites. Melanocytes are well known for their role in skin pigmentation, and their ability to produce and distribute melanin has been studied extensively. One of the factors that regulates melanocytes and skin pigmentation is the locally produced melanocortin peptide ␣ -MSH. The effects of ␣ -MSH on melanogenesis are mediated via the MC-1R and tyrosinase, the rate-limiting enzyme in the melanogenesis pathway. Binding of ␣ -MSH to its receptor increases tyrosinase activity and eumelanin production, which accounts for the skin-darkening effect of ␣ -MSH. Other ␣ -MSH-related melanocortin peptides, such as ACTH1-17 and desacetylated ␣ -MSH, are also agonists at the MC-1R and could regulate melanocyte function. Recent evidence shows that melanocytes have other functions in the skin in addition to their ability to produce melanin. They are able to secrete a wide range of signal molecules, including cytokines, POMC peptides, catecholamines, and NO in response to UV irradiation and other stimuli. Potential targets of these secretory products are keratinocytes, lymphocytes, fibroblasts, mast cells, and endothelial cells, all of which express receptors for these signal molecules. Melanocytes may therefore act as important local regulators of a range of skin cells. It has been shown that ␣ -MSH regulates NO production from melanocytes, and it is possible that the melanocortins regulate the release of other signalling molecules from melanocytes. Therefore, the melanocortin signaling system is one of the important regulators of skin homeostasis.

Silver enhancement of quantum dots resulting from (1) metabolism of toxic metals in animals and humans, (2) in vivo, in vitro and immersion created zinc-sulphur/ zinc-selenium nanocrystals, (3) metal ions liberated from metal implants and particles Abstract Autometallographic (AMG) silver enhancement is a potent histochemical tool for tracing a variety of metal containing nanocrystals, e.g. pure gold and silver nanoclusters and quantum dots of silver, mercury, bismuth or zinc, with sulphur and/or selenium.

A comparative histomorphological study was conducted on thymus of broiler chicken,
duck and quail. The thymus of all three species of post-hatch (adult) birds showed a thin connective
tissue capsule. However, fine septa originating from the capsule divided the organ into incomplete but
distinct lobules in chicken, whereas lobules were ill defined in both quail and duck. Each lobule, in
turn, was composed of a peripheral cortex, densely studded with lymphocytes and a central medulla
that was enriched with epithelial reticular cells. So, the cortex appeared more basophilic than that of
medulla. But the concentration of lymphocyte, an immune competent cell was highest in chicken
followed by duck and quail. Hassall’s corpuscles like structures were found inside the medulla as pale
stained diffuse body. General histo-architecture was almost similar in all the birds.

ABSTRAK Metode pewarnaan jaringan untuk mendeteksi adanya senyawa kimia di dalam jaringan salah satunya yaitu uji histokimia. Uji ini memerlukan reagen pewarna yang sesuai dengan senyawa yang ingin dideteksi. Praktikum ini bertujuan untuk mendeteksi keberadaan senyawa fitokimia pada bagian tertentu dari beberapa taksa tumbuhan dikotil dan monokotil. Sampel yang digunakan adalah umbi singkong, ubi jalar ungu, ubi kentang, air jagung, dan air kentang untuk uji amilum. Irisan jagung untuk uji selulosa, tempurung kelapa untuk uji lignin, daun kenanga dan daun jeruk untuk uji lipid, daun jambu untuk uji tanin, serta ubi jalar ungu dan jagung untuk uji gula reduksi. Metode yang dilakukan meliputi pembuatan preparat, pewarnaan, dan pengamatan. Pembuatan preparat dilakukan dengan membuat irisan sampel setipis mungkin ±5 µm menggunakan clamp on hand microtome, diletakkan di atas slide glass, ditetesi reagen pewarna spesifik, dan ditutup cover glas. Uji amilum menggunakan reagen lugol, gula pereduksi menggunakan reagen fehling diikuti proses pemanasan, selulosa menggunakan lugol dan H 2 SO 4 , lignin menggunakan reagen phloroglucin, lipid menggunakan reagen sudan III, serta tanin menggunakan FeCl 3 3% dan K 2 Cr 2 O 7 1%.

Natural products are studied to combat reproductive alterations of Lead. The current work aim to disclose the efficacy of Chlorella vulgaris and Zingiber officinale to alleviate lead acetate induced toxicity. Sixty adult male Wistar rats were distributed into four groups. Group 1 was considered control, group 2 received 200 mg/l PbAc water, group 3 received 50 mg/kg/rat of C. vulgaris extract and 200 mg/l PbAc water, and group 4 received 100 mg/kg/rat of Z. officinale and 200 mg/l PbAc water for 90 days. Testis samples were subjected to ultrastructural examination. It is observed that PbAc caused degenerative alterations in the spermatogenic series in many tubules, with a loss of germ cells and vacuoles inside the cytoplasm and between the germ cells. Mitochondria exhibited ballooning, with lost cristae and widening of the interstitial tissue, destructed nuclear envelopes of primary spermatocytes, and distortion of the axonemes of the mid-pieces of the sperms. With the treatment with C. vulgaris or Z. officinale, there were noticeable improvements in those modifications. It has concluded that both C. vulgaris and Z. officinale represent convincing medicinal components that may be used to ameliorate testicular toxicity in those exposed to lead in daily life with superior potentials revealed by C. vulgaris due to its chelating action.

Qualitative and quantitative analyses of carbohydrates In olive (Olea europaea L.) tissues have been carried out by HPLC-RI. Sample purification was by two SUccessive solid-liquid extractions to remove completely plant phenolics and pigments. Five carbohydrate peaks; SUcrose (staehyose + raffinose + sucrose), glucose, galactose, fructose (fructose + myo-inositol) and raannitol were detected when plant extracts were run on a Sugar SC 1011 column operating at 75 ~ using Water as eluent 0.5 ml min-1. The use of two serial Sugar SC 1011 columns operating at 90 ~ and eluting !he plant extracts with H20-CH3CN (95/5 v/v) enables !dentification and quantification of nine carbohydrate s, tncluding tetra and tri-saccharides.

Neutral buffered 4% formaldehyde fixation for 48 h preserved well the proteoglycan content of bovine articular cartilage. Neither subsequent demineralization in 10% EDTA, nor light microscopic tissue processing, reduced the hexosamine or uronic acid content of the tissue. Fixation in alcoholic solutions increased Safranin O binding as well as periodic acid Schiff reaction of the cartilage matrix as measured by microspectrophotometry. It is suggested that the enhanced staining of cartilage was due to better preservation of the glycoprotein oligosaccharides. Quaternary ammonium salts in the fixative suppressed the staining of cartilage matrix with Safranin O.

The antiapoptotic, antioxidant, proliferative, and angiogenic effects of metallothionein (MT)-I+II has resulted in increased focus on their role in oncogenesis, tumor progression, therapy response, and patient prognosis. Studies have reported increased expression of MT-I+II mRNA and protein in various human cancers; such as breast, kidney, lung, nasopharynx, ovary, prostate, salivary gland, testes, urinary bladder, cervical, endometrial, skin carcinoma, melanoma, acute lymphoblastic leukemia (ALL), and pancreatic cancers, where MT-I+II expression is sometimes correlated to higher tumor grade/stage, chemotherapy/radiation resistance, and poor prognosis. However, MT-I+II are downregulated in other types of tumors (e.g. hepatocellular, gastric, colorectal, central nervous system (CNS), and thyroid cancers) where MT-I+II is either inversely correlated or unrelated to mortality. Large discrepancies exist between different tumor types, and no distinct and reliable association exists between MT-I+II expression in tumor tissues and prognosis and therapy resistance. Furthermore, a parallel has been drawn between MT-I+II expression as a potential marker for prognosis, and MT-I+II's role as oncogenic factors, without any direct evidence supporting such a parallel. This review aims at discussing the role of MT-I+II both as a prognostic marker for survival and therapy response, as well as for the hypothesized role of MT-I+II as causal oncogenes.

The present study shows that aniline blue can be used as a fluorescent stain for glycogen. The dye is also helpful in tracing pathological and autolytic changes in lysosomes, mitochondria, erythrocytes and nuclei, and it can also be used for demonstrating bacteria in tissue sections and smears. The techniques used are simple, rapid and inexpensive.

The use of glycol methacrylate (GMA) avoids some technical artifacts, which are usually observed in paraffin-embedded sections, providing good morphological resolution. On the other hand, weak staining have been mentioned during the use of different methods in plastic sections. In the present study, changes in the histological staining procedures have been assayed during the use of staining and histochemical methods in different GMA-embedded tissues.

The main autocrine/paracrine role of the active metabolite of vitamin D(3), 1alpha,25-dihydroxyvitamin D(3) (1,25-D(3)), is inhibition of cell growth and induction of cell differentiation and/or apoptosis. Synthesis and degradation of the secosteroid occurs not only in the kidney but also in normal tissue or malignant extrarenal tissues such as the colon. Because 25-hydroxyvitamin D(3) 24-hydroxylase (CYP24A1) is considered to be the main enzyme determining the biological half-life of 1,25-D(3), we have examined expression of the CYP24A1 mRNA (by real-time RT-PCR) and protein (by immunohistochemistry) in normal human colon mucosa, colorectal adenomas, and adenocarcinomas in 111 patients. Although 76% of the normal and benign colonic tissue was either completely devoid of or expressed very low levels of CYP24A1, in the majority of the adenocarcinomas (69%), the enzyme was present at high concentrations. A parallel increased expression of the proliferation marker Ki-67 in the same sam...

The detailed characterization of multilayered Asian lacquer coatings is an important task for conservators in order to develop informed conservation and restoration approaches for complex Asian objects equipped with such decorative coatings. Of particular interest is often the identification of organic binders and their distribution within the layer structure. These days, the binding media contained in the individual lacquer layers are usually identified with sophisticated analytical equipment that is capable of great detail and precision, such as Fourier-transform infrared spectroscopy or pyrolysis-gas chromatography/mass spectrometry (PyGC/MS). However, the downside of using these techniques is that they are costly and not always accessible for many conservators, particularly at times when resources are tight. Alternative, low-tech methods that can be executed by the conservator himself are indeed available, but they are often deemed rather imprecise and potentially unreliable. Th...

A schedule for staining partially hydrated PAS-positive structures using non-aqueous solutions has been devised. Tissues are dewaxed, taken down to 70% alcohol, oxidised for 10 rain in a 1% w/v alcoholic solution of periodic acid, treated with an alcoholic solution of phosphotungstic acid-Schiff reagent complex (PTA-Schiff reagent) for 25 min, washed in alcohol, cleared in xylene and mounted in a synthetic medium. The PTA-Schiff reagent complex prepared from de Tomasi Schiff reagent by precipitation with PTA may be stored in the deep freeze for many months and dissolved freshly in alcohol for use. The PTA-Schiff reagent used as above allows staining of highly water soluble materials such as dextran. From blocking and digestion studies the mode of action seems similar to de Tomasi Schiff reagent. The partial hydration of the tissues prior to reaction was found to be essential for effective staining.

We compared the time course of myogenic events in vivo in regenerating whole muscle grafts in MyoD( Ϫ / Ϫ ) and control BALB/c adult mice using immunohistochemistry and electron microscopy. Immunohistochemistry with antibodies to desmin and myosin revealed a striking delay by about 3 days in the formation of myotubes in MyoD( Ϫ / Ϫ ) autografts compared with BALB/c mice. However, myotube formation was not prevented, and autografts in both strains appeared similar by 8 days. Electron microscopy confirmed myotube formation in 8-but not 5-day MyoD( Ϫ / Ϫ ) grafts. This pattern was not influenced by cross-transplantation experiments between strains examined at 5 days. Antibodies to proliferating cell nuclear antigen demonstrated an elevated level of replication by MyoD( Ϫ / Ϫ ) myoblasts in autografts, and replication was sustained for about 3 days compared with controls. These data indicate that the delay in the onset of differentiation and hence fusion is related to extended proliferation of the MyoD( Ϫ / Ϫ ) myoblasts. Overall, although muscle regeneration was delayed it was not impaired in MyoD( Ϫ / Ϫ ) mice in this model. (J Histochem Cytochem 48:1531-1543, 2000)

The classical von Kossa method has been modified: the high silver nitrate concentration in the original was replaced by 0.05% silver lactate with hydroquinone remaining the reducing agent of choice. The present modification stained calcification nodules with a sensitivity comparable to the original von Kossa reaction, but resulted in a reduced background staining in cultured osteoblasts. The method works well also with plastic-or paraffin-embedded tissue sections.

S U M M A R Y Development of the antigen retrieval (AR) technique, a simple method of boiling archival paraffin-embedded tissue sections in water to enhance the signal of immunohistochemistry (IHC), was the fruit of pioneering efforts guided by the philosophy of rendering IHC applicable to routine formalin-fixed, paraffin-embedded tissues for wide application of IHC in research and clinical pathology. On the basis of thousands of articles and many reviews, a book has recently been published that summarizes basic principles for practice and further development of the AR technique. Major topics with respect to several critical issues, such as the definition, application, technical principles, and further studies of the AR technique, are highlighted in this article. In particular, a further application of the heat-induced retrieval approach for sufficient extraction of nucleic acids in addition to proteins, and standardization of routine IHC based on the AR technique in terms of a test battery approach, are also addressed. Furthermore, understanding the mechanism of the AR technique may shed light on facilitating the development of molecular morphology.

Glandular trichomes of Labiatae are among the most investigated secretory structures. Most species studied belong to subfamily Nepetoidae, including plants with aromatic properties, while so far a few species of subfamily Lamioideae were examined. In this work, we studied the micromorphology, ultrastructure, type and release of secretion of the glandular trichomes present on leaves and flowers of several species belonging to subfamily Lamioideae, (Stachys alopecuros (L.) Bentham subsp. alopecuros, S. officinalis (L.) Trevisan subsp. officinalis, S. germanica L. subsp. germanica, S. germanica L. subsp. salviifolia (Ten.) Gams, S. sylvatica L., S. heraclea All., S. plumosa Griseb., S. annua L., Prasium majus L., Sideritis romana L.) and one to the sister group Scutellarioideae (Scutellaria galericulata L.). Besides the well-known peltate and small capitate trichomes, widely described in the literature, other types of glandular trichomes were encountered; stalked peltate hairs and large capitate hairs. In particular, a new type of capitate trichome, exclusive of calices and corollas, which presents a mode and release of secretion never described before, is reported.

We present a review of galanin in the brain from a historical perspective of the development of "chemoarchitectonics" and "brain cartography" accomplished in the Histopharmacology Section at the National Institutes of Health. It was the mapping of potential brain neuroregulators that served as a springboard of ideas from which behavioral studies emanate. The integration of the known localization of neurotransmitter/neuromodulatory nerves ("chemoarchitectonic maps") and receptor binding sites with biochemical data derived from brain micropunches coupled with behavioral analysis at the level of discrete brain allows one to define the anatomical circuits which support behavioral changes and which ultimately will improve our understanding of mental disorders.

Fishes have a great variety of structural and physiological adaptations that allow them to capture, digest and absorb food. In Hippocampus ingens it has been reported that they do not have teeth or stomach. However, it has the same intestinal structure as in other teleosts. In the present work the histological, histochemical characteristics and the presence of digestive enzymatic activity of the digestive tract of H. ingens are described with the purpose of providing information that can be used in the development of the culture of this species. We obtained 15 juveniles from a farm in Mazatlan, Sinaloa, Mexico. Some of them were fixed in the Davidson´s solution, sectioned at 4 μm using a rotatory microtome and stained with H-E, Alcian Blue-PAS, Toluidine Blue, Masson's Trichrome, Black Sudan and Ninhydrin-Schiff. To the rest, the digestive tract and the accessories were extracted to determine the presence of trypsin activity, chymotrypsin, lipase, amylase, aminopeptidase, acid phosphatase and alkaline phosphatase. The presence of an anterior and posterior esophagus was confirmed. Only the anterior region presents numerous acid-type mucosal cells, while the posterior region has simple cylindrical epithelium. Based on the type of epithelium, presence and height of villi as well as type and coverage of mucins present, the intestine differentiates into three regions. The anterior region presents acidic and neutral mucins, whereas in the middle and posterior regions it presents acidic mucins in greater production. The presence of vacuoles containing triglycerides within the enterocytes of the anterior intestine was recorded, as well as the proteins in the hepatocytes. The activity of aminopeptidase, chymotrypsin and amylase showed very low values with respect to lipase and alkaline phosphatase, which were the highest. Trypsin and acid phosphatase showed intermediate values. These results confirm that H. ingens presents an alkaline intestinal digestion and that it has high lipid requirements

S U M M A R Y Melanocytes are cells of neural crest origin. In the human epidermis, they form a close association with keratinocytes via their dendrites. Melanocytes are well known for their role in skin pigmentation, and their ability to produce and distribute melanin has been studied extensively. One of the factors that regulates melanocytes and skin pigmentation is the locally produced melanocortin peptide ␣ -MSH. The effects of ␣ -MSH on melanogenesis are mediated via the MC-1R and tyrosinase, the rate-limiting enzyme in the melanogenesis pathway. Binding of ␣ -MSH to its receptor increases tyrosinase activity and eumelanin production, which accounts for the skin-darkening effect of ␣ -MSH. Other ␣ -MSH-related melanocortin peptides, such as ACTH1-17 and desacetylated ␣ -MSH, are also agonists at the MC-1R and could regulate melanocyte function. Recent evidence shows that melanocytes have other functions in the skin in addition to their ability to produce melanin. They are able to secrete a wide range of signal molecules, including cytokines, POMC peptides, catecholamines, and NO in response to UV irradiation and other stimuli. Potential targets of these secretory products are keratinocytes, lymphocytes, fibroblasts, mast cells, and endothelial cells, all of which express receptors for these signal molecules. Melanocytes may therefore act as important local regulators of a range of skin cells. It has been shown that ␣ -MSH regulates NO production from melanocytes, and it is possible that the melanocortins regulate the release of other signalling molecules from melanocytes. Therefore, the melanocortin signaling system is one of the important regulators of skin homeostasis.

Psidium guineense, commonly known as “araçá”, is a traditional medicinal plant used to treat diarrhea. The present study examined the morphoanatomy, histochemistry and phytochemistry of P. guineense leaves to evaluate the presence and localization of pharmacologically active compounds. The anatomical study employed traditional light microscope techniques. Histochemical and phytochemical tests and thin-layer chromatography (TLC) were used to detect flavonoids, tannins and essential oils. The leaves of P. guineense show characteristics common to other species of Myrtaceae, such a marginal vein, a brochidodromous enervation pattern, simple tector trichomes, paracitic stomata, and secretory cavities. Histochemical tests indicated the occurrence of flavonoids and tannins in the mesophyll and vascular system, and flavonoids and essential oils in secretory cavities. Phytochemical tests confirmed the presence of these compounds. The TLC demonstrated the diversity of the chemical substances revealed by many Rfs for the different groups of compounds evaluated. The knowledge of the morpho-anatomical characteristics of P. guineense can aid botanical diagnoses of this species, which has secondary compounds of therapeutic application.

R S. While we were preparing this manuscript we received the news of the premature death of Prof.Jos~ L6pez Dfez del Corral, a former member of our group also involved in the study of the diffuse endocrine system. We want to dedicate these pages to his memory.

Information on the digestive system of the reptiles is based on relatively few studies on some of the now present 7500 reptilian species. Yet, the gap between our understanding of the major similarities and / or differences between the mammalian and reptilian digestive system does not seem satisfiable. The aim of the current study was to investigate the morphological structure of one of the most common reptilian species in Egypt, Varanus niloticus or Nile monitor. Specimens for histological examination were collected from the esophageus, stomach and small intestine of the Nile monitor and pro-cessed for paraffin embedding.

The fig (Ficus L.) infructescence, called syconium, is a receptacle with an apical opening, the ostiole, closed by bracts. The ostiolar bracts produce an exudate, which is rather conspicuous in some species. It has not been histochemically analyzed yet, and the structures responsible for its production are still unknown. Some wild growing species of Ficus from Brazil produce high amounts of this ostiolar exudate. Ficus enormis (Mart. ex Miq.) Miq. grows as trees or shrubs in the Atlantic rainforest. Our goal was to identify the secretory structures present in the inflorescence and, to characterize histochemically the ostiolar tissues and exudates. Syconia samples of F. enormis were processed and stained according to the usual techniques in plant anatomy. The morphological analysis revealed different types of bracts, one type specialized in secretion, another showing transitional characteristics between secretory and nonsecreting bracts, and a third one being non-secreting. They are designated as secretory ostiolar bracts, transitional bracts and wall bracts. The floral bracteoles, digital-shaped colleters present in the ostiole, at the syconium axis and at the flower receptacle, were also analyzed. All have similar structure, like fingershaped secretory trichomes. The colleters present among ostiolar bracts may contribute to production and composition of the ostiole exudate.

The cellular processes involved in metal metabolism in molluscs are reviewed, with emphasis on the contribution of microscopy (AMG, ARG, EPMA, and SIMS) to both basic research of metal cell biology and applied environmental research. In molluscs, metal uptake may occur by facilitated diffusion, active transport, or endocytosis, and can be enhanced by MT synthesis or formation of mineralized granules. In aquatic molluscs, gills constitute a key interface for dissolved metal uptake, where metals are bound to MT, incorporated into lysosomes, and released basally towards the blood plasma and circulating hemocytes. However, particulate metal uptake is mainly achieved via the digestive tract by endocytosis; further metals are transferred first to lysosomes and then to residual bodies, especially in the digestive cells of the digestive gland. Additionally, metals can be accumulated selectively in specific cell types. As ligands pools differ from cell to cell, different metals may be retained in different cell types. Class “a” metals are localized in cells with granules composed of carbonate, oxalate, phosphate, and sulfate (oxygen donors), whereas “b” metals are associated with those cell types rich in sulfur and nitrogen ligands (sulfur donors). In molluscs, oxygen donors occur in connective tissue calcium cells and basophilic cells, whereas sulfur donors are present in digestive cells, podocytes, nephrocytes, and rhogocytes. Hemocytes, which constitute the most relevant system for metal transport between tissues, move around the body and may penetrate tissues and remove metals from the inner medium to be accumulated in lysosomes as nondigested products. Rhogocytes also participate in metal mobilization, accumulation, and release. The assessment of metal levels in target cells of sentinel molluscs by microscopic techniques provides an early-warning measure, with promising applications as an exposure biomarker for environmental monitoring programs. Microsc. Res. Tech. 56:358–392, 2002. © 2002 Wiley-Liss, Inc.

The foliar cavities of the water fern Azolla filiculoides have as many as 20 -25 simple hairs (SH) protruding from the epidermal cells that delimit the cavity. These SH have a transfer-like ultrastructure normally associated with secretion of metabolites. The aim of this study was the chemical characterization of the compounds that accumulated in the SH of the zones F1-12 (from 1st to 12th leaves) and F13 (from 13th until the end of the sporophyte) throughout the seasons during a 1-year study. The histochemical tests show that the vacuoles of simple hairs contain a mixture of lipids, unsaturated lipids, polysaccharides, polyphenols (o-dihydroxyphenols, phenols with free À ÀOH groups and tannins) and alkaloids or alkaloidlike compounds. These substances do not show seasonal variation, having been present throughout the one-year study. The histochemical analysis demonstrated that the SH always have a variety of metabolites. The function within the Azolla-Anabaena symbiosis is not known.

In the physiology of placental blood circulation, nitric oxide (NO) synthases seem to play important roles, although their expression in pathological placentas and their role is still unclear. In addition, NO synthase activation seems to be related to estrogen receptor expression. Therefore, the aims of this study were to investigate the expression of estrogen receptors alpha (ER ␣ ), estrogen receptor beta (ER and the endothelial NO synthase (eNOS), and inducible NO synthase (iNOS) in intrauterine growth-restricted (IUGR) placentas, preeclamptic placentas, and in normal healthy control placentas. Slides of paraffin-embedded placental tissue were obtained after delivery from patients diagnosed with IUGR, preeclampsia, and normal term placentas and analyzed for eNOS, iNOS as well as ER ␣ and ER ␤ expression. Intensity of immunohistochemical reaction was analyzed using a semiquantitative score and statistical analysis was performed. In addition, Western blot experiments were performed for comparison of staining intensities obtained by immunohistochemistry and western blot. Expression of eNOS, iNOS, and ER ␤ is significantly reduced in trophoblast cells of placentas with IUGR. However, preeclamptic placentas demonstrated a significant elevated expression intensity of these proteins compared with normal controls. A different expression of eNOS, iNOS, ER ␣ , and ER ␤ by human trophoblast cells seems to results in lower NO output and impaired trophoblast invasion. Results obtained in our study provide evidence that reduced expression of the investigated proteins is related to IUGR. (J Histochem Cytochem 53:1441-1449, 2005) K E Y W O R D S nitric oxide synthases estrogen receptor alpha/beta intrauterine growth restriction preeclampsia

SUMMARY Carboxypeptidase E (CPE) is highly concentrated in neuroendocrine tissues and is the only carboxypeptidase detected in mature secretory vesicles. Carboxypeptidase D (CPD), a carboxypeptidase with CPE-like activity, is widely distributed in tissues and is present in the trans -Golgi network. Previous work had shown that both CPE and CPD are expressed in the human placenta and that CPD is

SUMMARY Semicarbazide-sensitive amine oxidase (SSAO), widely distributed in highly vascularized mammalian tissues, metabolizes endogenous and xenobiotic aromatic and aliphatic monoamines. To assess whether its physiological role in humans is restricted to oxidation, we used an immunohistochemical approach to examine the cellular localization of SSAO in human peripheral tissues (adrenal gland, duodenum, heart, kidney, lung, liver, pancreas, spleen, thyroid gland, and blood vessels) and also analyzed its subcellular localization. The results are in agreement with the specific activities also determined in the same samples and are discussed with reference to the tissue distribution of monoamine oxidase A and B. Together with the oxidative deamination of monoamines, SSAO cellular localization indicates that, in most human peripheral tissues, it might participate in the regulation of physiological processes via H2O2generation. (J Histochem Cytochem 49:209–217, 2001)