On the role of vitamin D binding globulin in glucose homeostasis: results from the San Luis Valley Diabetes Study

Several studies have reported association between noninsulin-dependent diabetes mellitus and GC, the vitamin D binding protein of human plasma, with the GC 1 allele in significant excess among diabetics. Additionally, there is a considerable body of animal data suggesting that vitamin D has a significant impact on insulin secretion. Examination of the insulin levels in Dogrib Indians showed that the lowest levels of fasting insulin were associated with the GC IF-IF genotype. The present study examined levels of glucose, C-peptide, and insulin at fasting and 1 hr and 2 hr following a 75 g oral glucose challenge, in a population of Hispanic-Americans and Anglos in the San Luis Valley of southern Colorado. The sample comprised a total of 468 individuals with normal glucose tolerance. Of these, 289 were Anglos and 179 were Hispanic-Americans. An analysis of covariance was performed to determine the effect of the GC genotypes on mean levels of the primary variables--glucose, C-peptide, and insulin--and a secondary variable--insulinogenic index adjusting for the covariates age, body mass index (BMI), gender, and ethnicity. The analyses revealed that there is a significant difference in mean levels of glucose at fasting (F value = 2.46; P = 0.033) among the GC genotypes in the sample. Additionally, the differences in mean levels of 1 hr postprandial glucose among the GC genotypes although not significant at a 5% level, were significant at the 10% level. No other significant phenotypic effects were observed. These analyses are not in concordance with the results of an earlier study, where lower fasting insulin was associated with the GC 1F-1F genotype.     

Laryngocoele: our experince

Laryngocoele is an extremely rare condition. Three cases of Laryngocoeles are presented. Two cases had infected laryngocoeles. The diagnosis was done clinically and confirmed radiologically. No predisposing factor was found except in one case who was a singer by profession and initially presented with stridor which was an unusual presentation. Surgical excision were done in two cases (case 1 and 3)and both the case were symptom free.     

Mapping quantitative trait loci in humans: achievements and limitations

Recent advances in statistical methods and genomic technologies have ushered in a new era in mapping clinically important quantitative traits. However, many refinements and novel statistical approaches are required to enable greater successes in this mapping. The possible impact of recent findings pertaining to the structure of the human genome on efforts to map quantitative traits is yet unclear.     

Antidepressant-like effects of 3,4-methylenedioxymethamphetamine in an animal model of depression

Increased synaptic serotonin (5-hydroxytryptamine) levels may underlie antidepressant-like effects of 3,4-methylenedioxymethamphetamine (MDMA) that may be more prominent in subjects with mood disturbance. The Flinders Sensitive Line (FSL) strain is an important animal model of depression. These rats are more immobile in the forced swimming test (FST), and their immobility is reversed by known antidepressants after prolonged administration. The objective of this study was to determine whether MDMA administration has a dose-dependent antidepressant-like effect in this animal model of depression. The effects of MDMA at 5 and 10 mg/kg following single and repeated administration were assessed in FSL rats using the FST. Sprague-Dawley rats were used as a control. During both FST sessions, saline-treated FSL rats were significantly more immobile than Sprague-Dawley rats (P<0.001). Acute MDMA administration had a dose-dependent antidepressant-like effect in FSL rats, which was most evident after 10 mg/kg. This effect was diminished after repeated administration. Methamphetamine 2 mg/kg, which was used as a positive control for locomotor activity induction, did not affect the depressive-like state in FSL rats. There were no changes in the cortical levels of 5-hydroxytryptamine and 5-hydroxyindoleacetic acid after treatments. It is concluded that MDMA exhibited an antidepressant-like effect in FSL rats, which was most evident following acute administration.     

Identification of prostate cancer modifier pathways using parental strain expression mapping

Inherited genetic risk factors play an important role in cancer. However, other than the Mendelian fashion cancer susceptibility genes found in familial cancer syndromes, little is known about risk modifiers that control individual susceptibility. Here we developed a strategy, parental strain expression mapping, that utilizes the homogeneity of inbred mice and genome-wide mRNA expression analyses to directly identify candidate germ-line modifier genes and pathways underlying phenotypic differences among murine strains exposed to transgenic activation of AKT1. We identified multiple candidate modifier pathways and, specifically, the glycolysis pathway as a candidate negative modulator of AKT1-induced proliferation. In keeping with the findings in the murine models, in multiple human prostate expression data set, we found that enrichment of glycolysis pathways in normal tissues was associated with decreased rates of cancer recurrence after prostatectomy. Together, these data suggest that parental strain expression mapping can directly identify germ-line modifier pathways of relevance to human disease.     

Thalidomide attenuates nitric oxide-driven angiogenesis by interacting with soluble guanylyl cyclase

Background and purpose:

Nitric oxide (NO) promotes angiogenesis by activating endothelial cells. Thalidomide arrests angiogenesis by interacting with the NO pathway, but its putative targets are not known. Here, we have attempted to identify these targets.

Experimental approach:

Cell-based angiogenesis assays (wound healing of monolayers and tube formation in ECV304, EAhy926 and bovine arterial endothelial cells), along with ex vivo and in vivo angiogenesis assays, were used to explore interactions between thalidomide and NO. We also carried out in silico homology modelling and docking studies to elucidate possible molecular interactions of thalidomide and soluble guanylyl cyclase (sGC).

Key results:

Thalidomide inhibited pro-angiogenic functions in endothelial cell cultures, whereas 8-bromo-cGMP, sildenafil (a phosphodiesterase inhibitor) or a NO donor [sodium nitroprusside (SNP)] increased these functions. The inhibitory effects of thalidomide were reversed by adding 8-bromo-cGMP or sildenafil, but not by SNP. Immunoassays showed a concentration-dependent decrease of cGMP in endothelial cells with thalidomide, without affecting the expression level of sGC protein. These results suggested that thalidomide inhibited the activity of sGC. Molecular modelling and docking experiments revealed that thalidomide could interact with the catalytic domain of sGC, which would explain the inhibitory effects of thalidomide on NO-dependent angiogenesis.

Conclusion and implications:

Our results showed that thalidomide interacted with sGC, suppressing cGMP levels in endothelial cells, thus exerting its anti-angiogenic effects. These results could lead to the formulation of thalidomide-based drugs to curb angiogenesis by targeting sGC.     

Headache in a case of Rhupus syndrome

We report a case of Rhupus with secondary anti-phospholipid syndrome who presented with headache and papilloedema due to cerebral venous thrombosis. We propose that an increased awareness about the condition and meticulous investigation of headaches in lupus can avert catastrophic outcomes.     

Histological characterization and development of mesial surface sulci in the human brain at 13–15 gestational weeks through high-resolution histology

Cellular-level anatomical data from early fetal brain are sparse yet critical to the understanding of neurodevelopmental disorders. We characterize the organization of the human cerebral cortex between 13 and 15 gestational weeks using high-resolution whole-brain histological data sets complimented with multimodal imaging. We observed the heretofore underrecognized, reproducible presence of infolds on the mesial surface of the cerebral hemispheres. Of note at this stage, when most of the cerebrum is occupied by lateral ventricles and the corpus callosum is incompletely developed, we postulate that these mesial infolds represent the primordial stage of cingulate, callosal, and calcarine sulci, features of mesial cortical development. Our observations are based on the multimodal approach and further include histological three-dimensional reconstruction that highlights the importance of the plane of sectioning. We describe the laminar organization of the developing cortical mantle, including these infolds from the marginal to ventricular zone, with Nissl, hematoxylin and eosin, and glial fibrillary acidic protein (GFAP) immunohistochemistry. Despite the absence of major sulci on the dorsal surface, the boundaries among the orbital, frontal, parietal, and occipital cortex were very well demarcated, primarily by the cytoarchitecture differences in the organization of the subplate (SP) and intermediate zone (IZ) in these locations. The parietal region has the thickest cortical plate (CP), SP, and IZ, whereas the orbital region shows the thinnest CP and reveals an extra cell-sparse layer above the bilaminar SP. The subcortical structures show intensely GFAP-immunolabeled soma, absent in the cerebral mantle. Our findings establish a normative neurodevelopment baseline at the early stage.     

Increased risk of oral cancer in relation to common Indian mitochondrial polymorphisms and Autosomal GSTP1 locus

BACKGROUND: Polymorphisms at mitochondrial (mt) loci could modulate the risk of diseases including cancers. Here the mtDNA polymorphisms at 12,308 nucleotide pairs (np), 11,467 np, 10,400 np, and 10,398 np were studied to examine the association with the risk of oral cancer and leukoplakia, alone and in combination with polymorphisms at the GST loci. METHODS: Polymorphisms at mt loci were screened in 310 cancer, 224 leukoplakia, and 389 control individuals by polymerase chain reaction (PCR) restriction length polymorphism (RFLP) and most of the GST genotype data were taken from previously published reports. Data were analyzed to determine the risk of the diseases. RESULTS: The major allele, A, at 12,308 np on tRNA(Leu) (CUN), increased the risk of cancer (odd ratio [OR] of 1.7; 95% confidence interval [95% CI], 1.1-2.6) but not that of leukoplakia. The same allele also appeared to increase the risk of cancer in smokers (OR of 4.0; 95% CI, 1.1-14.4), who are mostly males (OR of 1.8; 95% CI, 1.1-3-2), but not in smokeless tobacco users, who are mostly females. The major allele A at 11467 np demonstrated identical results as the major allele, A, at 12,308 np. The major alleles G at 10,398 np and T at 10,400 np (ie, M-haplogroup) increased the risk of cancer significantly in smokers (OR of 2.6; 95% CI, 1.2-5.7 and OR of 2.4; 95% CI, 1.1-5.1, respectively). The risk-risk genotype-allele combination at GSTP1 and mt12308 np loci increased the risk of cancer (OR of 2.6; 95% CI, 1.4-4.9) when compared with the nonrisk-nonrisk combination in leukoplakia patients. CONCLUSIONS: Polymorphisms at the mt loci alone and in combination with the risk genotype at GSTP1 increased the risk of oral cancer. Thus, risk genotypes from 2 different organelles may work in combination to increase the risk of oral cancer.