Studies of Association of Environmental Risk Factors in Down Syndrome

Down syndrome (DS) is the most common live-born birth defect in humans. The genetic cause of DS is trisomy of chromosome 21. 94% of cases of DS trisomy are due to maternal chromosomal non-disjunction. Advanced maternal age has been identified as a key risk factor for DS. However, it is not clearly understood yet how maternal age effect increases chromosome non-disjunction. Recently, it has been suggested that factors involved in meiotic chromosome segregation may be altered in aged oocytes and such molecular abnormality could be caused or accelerated by maternal environmental factors. Epidemiologic studies have tried to investigate effect of maternal environmental factors on DS. The most commonly-studied factors are maternal peri-conceptional smoking and oral contraceptive use. However, the evidence of association of those factors with DS has not been consistent. In this thesis, a DS cohort in Kolkata, India was investigated for studying association of maternal peri-conceptional behavioral factors on DS. The characteristics of exposure to two factors, smokeless chewing tobacco use (SCT) and oral contraceptive use (OC), are unique in this cohort as compared to previous study populations. In this population both exposures tend to be started early in life and in high dose. By using logistic and linear regression methods, I found significant association of maternal SCT and OC use with DS. SCT interacts with maternal age, having a stronger effect in younger mothers compared to older mothers, while the effect of OC use on risk is the same at all ages. SCT use is also associated with meiotic type (I vs. II) of chromosome non-disjunction and with lack of recombination in meiosis I type non-disjunction. Furthermore, maternal SCT use is strongly associated with maternal telomere length, which has been shown to be a molecular marker of aging. SCT use decreases maternal telomere length, especially among women bearing DS child with meiosis I type non-disjunction. In conclusion, with Indian DS cohort, this thesis was able to find evidence of interactions among three major risk factors in DS: tobacco use, oral contraceptive use, and maternal age. This study has great public health significance because better understanding of the risk factors for DS can lead to improved prevention and screening strategies

Maximum Gap in (Inverse) Cyclotomic Polynomial

Let $g(f)$ denote the maximum of the differences (gaps) between two consecutive exponents occurring in a polynomial $f$. Let $\Phi_n$ denote the $n$-th cyclotomic polynomial and let $\Psi_n$ denote the $n$-th inverse cyclotomic polynomial. In this note, we study $g(\Phi_n)$ and $g(\Psi_n)$ where $n$ is a product of odd primes, say $p_1 < p_2 < p_3$, etc. It is trivial to determine $g(\Phi_{p_1})$, $g(\Psi_{p_1})$ and $g(\Psi_{p_1p_2})$. Hence the simplest non-trivial cases are $g(\Phi_{p_1p_2})$ and $g(\Psi_{p_1p_2p_3})$. We provide an exact expression for $g(\Phi_{p_1p_2}).$ We also provide an exact expression for $g(\Psi_{p_1p_2p_3})$ under a mild condition. The condition is almost always satisfied (only finite exceptions for each $p_1$). We also provide a lower bound and an upper bound for $g(\Psi_{p_1p_2p_3})$

Roles of 17-AAG-induced molecular chaperones and Rma1 E3 ubiquitin ligase in folding and degradation of Pendrin

AbstractPendrin is a transmembrane chloride/anion exchanger highly expressed in thyroid, kidney, and inner ear. Endoplasmic reticulum (ER)-retention of improperly folded Pendrin mutants is considered as the major cause for Pendred syndrome. However, the folding and degradation mechanisms of Pendrin are poorly understood. Here, we report that treatment of 17-AAG, an Hsp90 inhibitor, facilitates the folding of Pendrin through heat shock transcription factor 1 (Hsf1)-dependent induction of molecular chaperones. Furthermore, we demonstrate that Rma1, an E3 ubiquitin ligase localized in the ER membrane, is involved in Pendrin degradation

Effects of processing and storage on selected nutrients in soymilk

Call number: LD2668 .T4 1986 H664Master of ScienceHuman Nutritio

Surgical experience of pericardial mesothelioma presenting as constrictive pericarditis

SummaryWe report two cases, which had been initially diagnosed with constrictive pericarditis but later were definitely diagnosed with mesothelioma after receiving pericardiectomy. The two patients complained of dyspnea. Chest computed tomography showed mild pericardial effusion and thickened pericardium, which was found enveloping the heart without any lumps. Pericardiectomy (phrenic nerve to phrenic nerve) was performed and post-operative histology confirmed malignant mesothelioma. One patient had recurrence near the pericardium at 7 months post-operatively and died at 11 months post-operatively. Another patient, after receiving chemotherapy, is still alive at 16 months post-operatively. We consider that pericardial mesothelioma, an extremely rare disease exhibiting clinical signs similar to those of constrictive pericarditis, must be diagnosed at the early stage of its onset

Effect of electrolytes on the electrochemical performance of nickel cobaltite–titania nanotubes composites as supercapacitive materials

The effects of electrolytes on the electrochemical performance of nickel cobaltite–titania nanotubes composites as electrochemical capacitors were evaluated. Four types of electrolytes were selected to assess their effects on the prepared composites, namely aqueous electrolytes of 1.0 M KCl, 1.0 M HCl, 1.0 M KOH; and an organic electrolyte, 0.27 M tetra-n-butylammonium tetrafluoroborate (TBATFB) ionic liquid salt in acetonitrile. The composites performed better in 1.0 M HCl and 1.0 M KOH, than in 1.0 M KCl and 0.27 M TBATFB, which suggested that aqueous electrolytes with non-neutral pH would improve the specific areal capacitance values of the composites. Results have shown optimal performance in 1.0 KOH, which endowed the composite with excellent rate capability up to 200 mV s−1. Cyclic voltammogram of the composite analysed in 1.0 M KOH produced a leaf-shaped like profile, with higher current densities towards more positive potentials. Charge–discharge analyses in 1.0 M KOH has shown that the composite possessed specific areal capacitance of up to 214.76 µF cm−2 when it was evaluated at the current density of 350 µA cm−2. The composite also retained up to 97.79% of its specific areal capacitance when current density was increased to 400 µA cm−2. This material has demonstrated potential application for electrochemical capacitors through its facile fabrication technique

Pluripotency factors functionally premark cell-type-restricted enhancers in ES cells.

Enhancers for embryonic stem (ES) cell-expressed genes and lineage-determining factors are characterized by conventional marks of enhancer activation in ES cells1-3, but it remains unclear whether enhancers destined to regulate cell-type-restricted transcription units might also have distinct signatures in ES cells. Here we show that cell-type-restricted enhancers are 'premarked' and activated as transcription units by the binding of one or two ES cell transcription factors, although they do not exhibit traditional enhancer epigenetic marks in ES cells, thus uncovering the initial temporal origins of cell-type-restricted enhancers. This premarking is required for future cell-type-restricted enhancer activity in the differentiated cells, with the strength of the ES cell signature being functionally important for the subsequent robustness of cell-type-restricted enhancer activation. We have experimentally validated this model in macrophage-restricted enhancers and neural precursor cell (NPC)-restricted enhancers using ES cell-derived macrophages or NPCs, edited to contain specific ES cell transcription factor motif deletions. DNA hydroxyl-methylation of enhancers in ES cells, determined by ES cell transcription factors, may serve as a potential molecular memory for subsequent enhancer activation in mature macrophages. These findings suggest that the massive repertoire of cell-type-restricted enhancers are essentially hierarchically and obligatorily premarked by binding of a defining ES cell transcription factor in ES cells, dictating the robustness of enhancer activation in mature cells