Biomedical subjects
Publications and source records attributed to S Kanekar.
We report a case of severe cervical spondylosis and atlantoaxial dislocation (AAD) in association with idiopathic cervical dystonia (ICD) in a middle-aged male. To our knowledge, this is the first case of ICD reported in association with AAD.
The eyeless inbred mouse strain ZRDCT has long served as a spontaneous model for human anophthalmia and the evolutionary reduction of eyes that has occurred in some naturally blind mammals. ZRDCT mice have orbits but lack eyes and optic tracts and have hypothalamic abnormalities. Segregation data suggest that a small number of interacting genes are responsible, including at least one major recessive locus, ey1. Although predicted since the 1940s, these loci were never identified. We mapped ey1 to chromosome 18 using an F2 genome scan and there found a Met10-->Leu mutation in Rx/rax, a homeobox gene that is expressed in the anterior headfold, developing retina, pineal, and hypothalamus and is translated via a leaky scanning mechanism. The mutation affects a conserved AUG codon that functions as an alternative translation initiation site and consequently reduces the abundance of Rx protein. In contrast to a targeted Rx null allele, which causes anophthalmia, central nervous system defects, and neonatal death, the hypomorphic M10L allele is fully viable.
The authors used vignettes to solicit each participant's estimate of the likelihood of help and his/her recommendation for or against helping a student who needed to borrow another student's class notes. The study had a 2 (Hindu vs. Muslim participant) x 2 (participant's gender) x 2 (liking vs. disliking relationship) x 2 (justified vs. unjustified need for help) x 2 (low vs. high cost of helping) factorial design with 15 participants per cell. Estimated likelihood of help was higher among the female than among the male participants, with the liking than with the disliking relationship, and with the low rather than with the high cost of helping. The Hindu participants gave lower estimates of the likelihood of help than did the Muslim participants with the disliking relationship and with the unjustified need for help. Intracommunal helping, irrespective of contextual variations, may have been a stronger social norm for the Muslim than for the Hindu participants, probably because of the former's minority status in India and, more important, the Islamic prescription of communal brotherhood. Even though both communities are deemed collectivist, the Indian Muslim participants' helping norms appeared to be more obligation oriented and less option oriented than those of the Indian Hindu participants.
134 undergraduate students of the history of psychology from 1998 through 2000 were requested to name three psychologists in order of importance, eminence, or influence within as well as outside the discipline of psychology. Salient was confirmation of Sigmund Freud as outranking other psychologists by a wide margin.
Dynamic interactions between cells and the extracellular matrix are essential in the regulation of a number of cellular processes including migration, adhesion, proliferation and differentiation. A variety of factors have been identified which modulate these interactions including transforming growth factor-beta, platelet-derived growth factor and others. Insulin-like growth factors have been shown to regulate collagen production by heart fibroblasts; however, the effects of this growth factor on the interactions of heart fibroblasts with the extracellular matrix have not been examined. The present studies were carried out to determine the effects of IGF-I on the ability of fibroblasts to interact with the extracellular matrix and to begin to determine the mechanisms of this response. These experiments illustrate that IGF-I treatment results in increased migration, collagen reorganization and gel contraction by heart fibroblasts. IGF-I has been shown to activate both the mitogen-activated protein kinase and phophatidylinositol-3 kinase pathways in isolated cells. Experiments with pharmacological antagonists of these pathways indicate that the mitogen-activated protein kinase pathway is essential for IGF-I stimulated collagen gel contraction by fibroblasts. These studies illustrate that IGF-I modulates the ability of fibroblasts to interact with the collagen matrix and that activation of multiple signaling pathways by IGF-I may produce distinct downstream responses in these cells.
The ciliary marginal zone is a perpetually self-renewing proliferative neuroepithelium at the perimeter of the retina in amphibians and fish. In the ciliary marginal zone (CMZ), cells are spatially ordered with respect to cellular development, deep stem cells being most peripheral and differentiating retinal progenitors being most central. This spatial gradient in the CMZ recapitulates embryonic retinogenesis and provides a powerful system to examine the relative order of gene expression during this process. A number of neurogenic and proneural genes have been described to have interacting roles in the development of the vertebrate nervous system, and so it is of major importance to put these genes in a hierarchical pathway. In no other system yet described are the developmental stages of neurogenesis arrayed so clearly in a spatial pattern as in the CMZ. We have therefore taken advantage of this system, using double in situ hybridizations on cross sections of the CMZ, to compare the spatial patterns of 15 proneural, neurogenic, and other genes involved in early and late phases of retinal development. In addition, we have positioned these expression patterns with respect to cell division. What emerges from this work is a spatial ordering of gene expression that predicts a genetic hierarchy governing vertebrate retinogenesis. By injecting messenger RNA for some of these genes into blastomeres of the Xenopus embryo and examining the effects on expression of the putative downstream genes, we have been able to corroborate some of the relationships between genes predicted to act sequentially.
Formerly a fatal condition, Wegener's granulomatosis is now treated with good results. Although the annual incidence of Wegener's granulomatosis in the general population is not known, most European and American studies revealed an incidence in the range of one for every 250,000 of the population. The estimated total population of Bahrain as of June 1997 is 586,110; here we report the first diagnosed case of Wegener's granulomatosis in Bahrain. Our patient presented with epistaxis, and from the clinical features, the very high ESR, the operative, histopathological and the radiological findings, and a high index of suspicion we could confirm the diagnosis along with the appropriate immunological test (positive cANCA). Standard treatment with cytotoxic agents and corticosteroids has been used. On follow-up the patient has shown a progressive improvement in her clinical and laboratory parameters.
We have identified Math5, a mouse basic helix-loop-helix (bHLH) gene that is closely related to Drosophila atonal and Xenopus Xath5 and is largely restricted to the developing eye. Math5 retinal expression precedes differentiation of the first neurons and persists within progenitor cells until after birth. To position Math5 in a hierarchy of retinal development, we compared Math5 and Hes1 expression in wild-type and Pax6-deficient (Sey) embryos. Math5 expression is downregulated in Sey/+ eyes and abolished in Sey/Sey eye rudiments, whereas the bHLH gene Hes1 is upregulated in a similar dose-dependent manner. These results link Pax6 to the process of retinal neurogenesis and provide the first molecular correlate for the dosage-sensitivity of the Pax6 phenotype. During retinogenesis, Math5 is expressed significantly before NeuroD, Ngn2 or Mash1. To test whether these bHLH genes influence the fates of distinct classes of retinal neurons, we ectopically expressed Math5 and Mash1 in Xenopus retinal progenitors. Unexpectedly, lipofection of either mouse gene into the frog retina caused an increase in differentiated bipolar cells. Directed expression of Math5, but not Xath5, in Xenopus blastomeres produced an expanded retinal phenotype. We propose that Math5 acts as a proneural gene, but has properties different from its most closely related vertebrate family member, Xath5.
The hypothesis that causality and blame will be differently affected by agential distance within a two-step causal chain was tested. A hypothetical medical accident was presented to 360 female college students in India, who gave causality, blame, or punishment judgments about either the proximal agent or the distal agent. The study had a 2 (proximal vs. distal agent) x 2 (high vs. low extenuation) x 2 (mild vs. severe outcome) x 3 (casuality, blame, or punishment judgments) fully crossed, between-subjects factorial design, with 15 participants per cell. In support of the basic hypothesis, more blame and punishment were assigned to the distal agent than to the proximal agent, whereas agential distance did not affect causal attribution. Extenuation was effective on causality and blame judgments only when the outcome was mild, and there was no effect of extenuation on punishment judgments, irrespective of outcome severity.
We examined the function of basic-helix-loop-helix (bHLH) transcription factors during retinal neurogenesis. We identified Xath5, a Xenopus bHLH gene related to Drosophila atonal, which is expressed in the developing Xenopus retina. Targeted expression of Xath5 in retinal progenitor cells biased the differentiation of these cells toward a ganglion cell fate, suggesting that Xath5 can regulate the differentiation of retinal neurons. We examined the relationship between the three bHLH genes Xash3, NeuroD, and Xath5 during retinal neurogenesis and found that Xash3 is expressed in early retinoblasts, followed by coexpression of Xath5 and NeuroD in differentiating cells. We provide evidence that the expression of Xash3, NeuroD, and Xath5 is coupled and propose that these bHLH genes regulate successive stages of neuronal differentiation in the developing retina.
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A mixed factorial design was used to examine the physical attractiveness stereotype in the context of consumer behavior, with physical attractiveness and clothing elegance as between-subjects variables and type of consumer product as a within-subject variable. Female graduate students in India were shown photographs of a young female model and were asked to indicate the quality of four consumer products that the model was likely to choose. Product quality was rated higher for the attractive model than for the plain (nonattractive) model, but the difference was significant only for beauty products. Product quality was rated higher for the elegantly dressed model than for the model who was not elegantly dressed, irrespective of product type.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.