Papers by Edgard Espinoza
We present a case of primary abdominal pregnancy that represented a diagnostic and therapeutic ch... more We present a case of primary abdominal pregnancy that represented a diagnostic and therapeutic challenge because its inespecific clinical presentation. Knowledge of the differential diagnosis and the complications of abdominal pregnancy is required to avoid the mistakes that could be life threatening for the mother. A review of the literature is done, as well. (Rev. Med Hered 1997; 8: 78-82).
Forensic Science International, 2000
In order to elucidate the discriminating power of various soil analytical techniques, over 100 so... more In order to elucidate the discriminating power of various soil analytical techniques, over 100 soils samples were analyzed using conventional analysis (i.e., color, percent organic and density gradient) and a novel FTIR technique. The FTIR technique involves collecting a spectrum of a soil sample that has been oxidatively pyrolysed, and therefore all organic have been degraded. This spectrum is subtracted from the spectrum of the same sample that contained the organic prior to pyrolysis. This resultant IR spectrum represents the organic portion of the sample. The use of organic components increases the discrimination in soils that are otherwise similar. We have illustrated the usefulness of this technique by selecting four soil samples, which have identical Munsel color values but can be discriminated by subtractive ETIR. We propose that the ETIR spectra of the organic portion of soil serves a useful purpose in forensic investigations.
Analytical Biochemistry, 1999
All rights reserved EuroPEAN JourNAL of MASS SPEctroMEtry the development of electrospray ionizat... more All rights reserved EuroPEAN JourNAL of MASS SPEctroMEtry the development of electrospray ionization mass spectrometry (ESI-MS) has provided an excellent tool to study noncovalent interactions of biomolecules under controlled experimental conditions. 1 for example, the structures of oxytocin complexes with nickel and copper ions were investigated by this technique. 2 tandem mass spectrometry has been used to yield singly-and multiply charged fragment ions that can be assigned to the known sequence of the protein. 3 ESI tandem mass spectrometry (MS/MS) experiments were used to provide evidence regarding the sites of interactions between zinc metal ions and angiotensin peptides. 4 Mass spectrometry-based methods were used to study protein amyloid formation. 5 Metal-catalyzed oxidation reactions and mass spectrometry can be used together to determine the amino acids bound to copper in a metalloprotein. 6 conformations of metal ions binding to peptides have been studied to explain the biological activity difference in the physiological solution. 2 Besides, the copper(II) and nickel(II) binding ability of the multi-histidine peptide N-acetyl-His-Pro-His-His-NH 2 has been studied by combined pH-potentiometry and visible, circular dichroism (cD) and electron paramagnetic resonance (EPr) spectroscopies. 7 conformationally-induced metal ion binding to peptides seems to be involved in the generation of reactive oxygen species and mitochondrial dysfunction, being implicated in numerous but devastating classes of neurodegenerative disorders. 8 Metal ions may interact with both amyloid precursor protein (APP) and Ab to potentiate Alzheimer's disease (AD) by participating in the aggregation of these normal cellular proteins and in the generation of reactive oxygen species. Although histidine-containing peptides generally bind heavy metal ions, the secondary structure of such peptides Electrospray ionization mass spectrometric approach of conformationally-induced metal binding to oligopeptides Electrospray ionization mass spectrometry was used to measure the binding of copper and nickel ions to the newly synthesized model peptides H 2 N-AAAAHAAAAHAAAAHAAAA-COOH (P19-H5) and H 2 N-AAAHAAAHAAAHAAAAAAA-COOH (P19-H4). The affinity of histidine-containing peptides toward heavy metal ions proved to be related to the position of each histidine residue in the peptide sequence. In contrast to P19-H5, P19-H4 peptide bound no nickel or copper ions in the gas phase, whereas its spectra showed an intense fragmentation. The role of spacing residues (Ala repeats) in selecting the various conformations was also investigated. Finally, the circular dichroism and Fourier transform infrared spectra indicated that these isomer peptides have quite different conformations. A close relationship between the conformation of alanine-based peptides and their affinity toward metal ions may result in different patterns of metal ion-peptide systems.
New England Journal of Medicine, 1995
Lancet
Fourier-transform infrared spectroscopy (FTIR), discriminate analysis, X-ray fluorescence spectro... more Fourier-transform infrared spectroscopy (FTIR), discriminate analysis, X-ray fluorescence spectrometry (XRF), and stereoscopic microscopy were used to separate black coral forensic evidence items from similarly appearing items manufactured from plastics, bovid keratin, and mangrove wood. In addition, novel observations were made of bromine and iodine relationships in black coral that have not been previously reported.
Marine Mammal Science, 2003
Forensic Science Medicine and Pathology, 2010
Here we present methods for distinguishing tail hairs of African elephants (Loxodonta africana), ... more Here we present methods for distinguishing tail hairs of African elephants (Loxodonta africana), Asian elephants (Elephas maximus), and giraffes (Giraffa camelopardalis) from forensic contexts. Such hairs are commonly used to manufacture jewelry artifacts that are often sold illegally in the international wildlife trade. Tail hairs from these three species are easily confused macroscopically, and morphological methods for distinguishing African and Asian tail hairs have not been published. We used cross section analysis and light microscopy to analyze the tail hair morphology of 18 individual African elephants, 18 Asian elephants, and 40 giraffes. We found that cross-sectional shape, pigment placement, and pigment density are useful morphological features for distinguishing the three species. These observations provide wildlife forensic scientists with an important analytical tool for enforcing legislation and international treaties regulating the trade in elephant parts.
Analytica Chimica Acta, 1994
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Papers by Edgard Espinoza