A 78-year-old man with a history of parathyroidectomy presented with hyperparathyroidism and trac... more A 78-year-old man with a history of parathyroidectomy presented with hyperparathyroidism and tracheal obstruction. After excision of the mediastinal parathyroid cyst, his symptoms were completely relieved. The diagnosis, investigations, and management are discussed.
Proceedings of The National Academy of Sciences, 2003
Monovalent-cation-activated enzymes are abundantly represented in plants and in the animal world.... more Monovalent-cation-activated enzymes are abundantly represented in plants and in the animal world. Most of these enzymes are specifically activated by K ؉ , whereas a few of them show preferential activation by Na ؉ . The monovalent cation specificity of these enzymes remains elusive in molecular terms and has not been reengineered by site-directed mutagenesis. Here we demonstrate that thrombin, a Na ؉ -activated allosteric enzyme involved in vertebrate blood clotting, can be converted into a K ؉ -specific enzyme by redesigning a loop that shapes the entrance to the cation-binding site. The conversion, however, does not result into a K ؉ -activated enzyme.
To confirm that corticosteroids are beneficial in the treatment of Stevens-Johnson syndrome (SJS)... more To confirm that corticosteroids are beneficial in the treatment of Stevens-Johnson syndrome (SJS), 15 patients with the syndrome were evaluated by the same group of physicians over 2 years. All patients had cutaneous and most had mucosal lesions. Patients were treated with corticosteroids ranging from prednisone 40 mg daily to methylprednisolone 750 mg daily. The same group of physicians participated in the management of these patients until recovery. No deaths occurred among the 15 patients. Recovery was complete in all cases, and there was no residual skin, mucosal, or visceral damage except for minimal scarring in one patient. In some cases, reversal of disease after onset of corticosteroid therapy was sufficiently dramatic to demonstrate a benefit. The use of corticosteroids in the treatment of SJS remains controversial. We conclude that corticosteroids are beneficial in treatment of the syndrome. They may be lifesaving in some patients and should be the standard of therapy. SJS should be considered to be erythema multiforme with either bullous lesions or visceral involvement or both.
A sign pattern Z (a matrix whose entries are elements of {+, −, 0}) is spectrally arbitrary if fo... more A sign pattern Z (a matrix whose entries are elements of {+, −, 0}) is spectrally arbitrary if for any selfconjugate spectrum there is a real matrix with sign pattern Z having the given spectrum. Spectrally arbitrary sign patterns were introduced in [5], where it was (incorrectly) stated that if a sign pattern Z is reducible and each of its irreducible components is a spectrally arbitrary sign pattern, then Z is a spectrally arbitrary sign pattern, and it was conjectured that the converse is true as well; we present counterexamples to both of these statements. In it was conjectured that any n × n spectrally arbitrary sign pattern must have at least 2n nonzero entries; we establish that this conjecture is true for 5 × 5 sign patterns. We also establish analogous results for nonzero patterns.
Human reproductive failure may be a consequence of aberrant expression of immunological factors d... more Human reproductive failure may be a consequence of aberrant expression of immunological factors during pregnancy. Although the relative importance of immunological factors in human reproduction remains controversial, substantial evidence suggests that human leukocyte antigens (HLA), antisperm antibodies, integrins, the leukaemia inhibitory factor (LIF), cytokines, antiphospholipid antibodies, endometrial adhesion factors, mucins (MUC1) and uterine natural killer cells contribute to reproductive failure. In contrast, fewer data support the roles of anti-trophoblast antibodies, anti-endometrial antibodies, T-cells, peripheral natural killer cells, anti-HLA antibodies, blocking antibodies and suppressor cells in reproductive failure. Although immunological factors involved in reproductive failure have been studied traditionally using assays for antibodies and/or antigens, detailed research on these factors demonstrates con¯icting results in humans. Maternal and fetal immunology is also dif®cult to investigate in humans. For these reasons, molecular assays may serve as a valuable alternative to investigate how the immune system affects reproductive outcome. In Part I of this review, immunological factors involved in human reproductive failure are summarized and critically evaluated. Immunogenetic and interacting factors in human reproductive failure will be summarized and evaluated in Part II.
The set of real matrices described by a sign pattern (a matrix whose entries are elements of {+, ... more The set of real matrices described by a sign pattern (a matrix whose entries are elements of {+, −, 0}) has been studied extensively but only loose bounds were available for the minimum rank of a tree sign pattern. A simple graph has been associated with the set of symmetric matrices having a zero-nonzero pattern of off-diagonal entries described by the graph, and the minimum rank/maximum eigenvalue multiplicity among matrices in this set is readily computable for a tree. In this paper, we extend techniques for trees to tree sign patterns and trees allowing loops (with the presence or absence of loops describing the zero-nonzero pattern of the diagonal), allowing precise computation of the minimum rank of a tree sign pattern and a tree allowing loops. For a symmetric tree sign pattern or a tree that allows loops, we provide an algorithm that allows exact computation of maximum multiplicity and minimum rank, and can be used to obtain a symmetric integer matrix realizing minimum rank.
The theoretical methodology adopted in this research study has been developed according to an exi... more The theoretical methodology adopted in this research study has been developed according to an existing methodology which was designed in measuring the quality of online services offered by the HSBC bank. Mathematical analysis has been conducted on the basis of experiential data which has been collected via quantitative research techniques along with the design & the distribution of a questioner. The original theoretical methodology has been
A 78-year-old man with a history of parathyroidectomy presented with hyperparathyroidism and trac... more A 78-year-old man with a history of parathyroidectomy presented with hyperparathyroidism and tracheal obstruction. After excision of the mediastinal parathyroid cyst, his symptoms were completely relieved. The diagnosis, investigations, and management are discussed.
Proceedings of The National Academy of Sciences, 2003
Monovalent-cation-activated enzymes are abundantly represented in plants and in the animal world.... more Monovalent-cation-activated enzymes are abundantly represented in plants and in the animal world. Most of these enzymes are specifically activated by K ؉ , whereas a few of them show preferential activation by Na ؉ . The monovalent cation specificity of these enzymes remains elusive in molecular terms and has not been reengineered by site-directed mutagenesis. Here we demonstrate that thrombin, a Na ؉ -activated allosteric enzyme involved in vertebrate blood clotting, can be converted into a K ؉ -specific enzyme by redesigning a loop that shapes the entrance to the cation-binding site. The conversion, however, does not result into a K ؉ -activated enzyme.
To confirm that corticosteroids are beneficial in the treatment of Stevens-Johnson syndrome (SJS)... more To confirm that corticosteroids are beneficial in the treatment of Stevens-Johnson syndrome (SJS), 15 patients with the syndrome were evaluated by the same group of physicians over 2 years. All patients had cutaneous and most had mucosal lesions. Patients were treated with corticosteroids ranging from prednisone 40 mg daily to methylprednisolone 750 mg daily. The same group of physicians participated in the management of these patients until recovery. No deaths occurred among the 15 patients. Recovery was complete in all cases, and there was no residual skin, mucosal, or visceral damage except for minimal scarring in one patient. In some cases, reversal of disease after onset of corticosteroid therapy was sufficiently dramatic to demonstrate a benefit. The use of corticosteroids in the treatment of SJS remains controversial. We conclude that corticosteroids are beneficial in treatment of the syndrome. They may be lifesaving in some patients and should be the standard of therapy. SJS should be considered to be erythema multiforme with either bullous lesions or visceral involvement or both.
A sign pattern Z (a matrix whose entries are elements of {+, −, 0}) is spectrally arbitrary if fo... more A sign pattern Z (a matrix whose entries are elements of {+, −, 0}) is spectrally arbitrary if for any selfconjugate spectrum there is a real matrix with sign pattern Z having the given spectrum. Spectrally arbitrary sign patterns were introduced in [5], where it was (incorrectly) stated that if a sign pattern Z is reducible and each of its irreducible components is a spectrally arbitrary sign pattern, then Z is a spectrally arbitrary sign pattern, and it was conjectured that the converse is true as well; we present counterexamples to both of these statements. In it was conjectured that any n × n spectrally arbitrary sign pattern must have at least 2n nonzero entries; we establish that this conjecture is true for 5 × 5 sign patterns. We also establish analogous results for nonzero patterns.
Human reproductive failure may be a consequence of aberrant expression of immunological factors d... more Human reproductive failure may be a consequence of aberrant expression of immunological factors during pregnancy. Although the relative importance of immunological factors in human reproduction remains controversial, substantial evidence suggests that human leukocyte antigens (HLA), antisperm antibodies, integrins, the leukaemia inhibitory factor (LIF), cytokines, antiphospholipid antibodies, endometrial adhesion factors, mucins (MUC1) and uterine natural killer cells contribute to reproductive failure. In contrast, fewer data support the roles of anti-trophoblast antibodies, anti-endometrial antibodies, T-cells, peripheral natural killer cells, anti-HLA antibodies, blocking antibodies and suppressor cells in reproductive failure. Although immunological factors involved in reproductive failure have been studied traditionally using assays for antibodies and/or antigens, detailed research on these factors demonstrates con¯icting results in humans. Maternal and fetal immunology is also dif®cult to investigate in humans. For these reasons, molecular assays may serve as a valuable alternative to investigate how the immune system affects reproductive outcome. In Part I of this review, immunological factors involved in human reproductive failure are summarized and critically evaluated. Immunogenetic and interacting factors in human reproductive failure will be summarized and evaluated in Part II.
The set of real matrices described by a sign pattern (a matrix whose entries are elements of {+, ... more The set of real matrices described by a sign pattern (a matrix whose entries are elements of {+, −, 0}) has been studied extensively but only loose bounds were available for the minimum rank of a tree sign pattern. A simple graph has been associated with the set of symmetric matrices having a zero-nonzero pattern of off-diagonal entries described by the graph, and the minimum rank/maximum eigenvalue multiplicity among matrices in this set is readily computable for a tree. In this paper, we extend techniques for trees to tree sign patterns and trees allowing loops (with the presence or absence of loops describing the zero-nonzero pattern of the diagonal), allowing precise computation of the minimum rank of a tree sign pattern and a tree allowing loops. For a symmetric tree sign pattern or a tree that allows loops, we provide an algorithm that allows exact computation of maximum multiplicity and minimum rank, and can be used to obtain a symmetric integer matrix realizing minimum rank.
The theoretical methodology adopted in this research study has been developed according to an exi... more The theoretical methodology adopted in this research study has been developed according to an existing methodology which was designed in measuring the quality of online services offered by the HSBC bank. Mathematical analysis has been conducted on the basis of experiential data which has been collected via quantitative research techniques along with the design & the distribution of a questioner. The original theoretical methodology has been
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