Modelling studies on neurodegenerative disease causing triplet repeat sequences d(CGG/GCC) and d(CAG/CTG): Duplexes vs Quadruplexes

Model building and molecular mechanics studies have been carried out to examine the potential structures for d(GGC/GCC)5 and d(CAG/CTG)5 that might relate to their biological function and association with triplet repeat expansion diseases. Model building studies suggested that hairpin and quadruplex structures could be formed with these repeat sequences. Molecular mechanics studies have demonstrated that the hairpin and hairpin dimmer structures of triplet repeat sequences formed by looping out of the two strands are as favourable as the corresponding B-DNA type hetero duplex structures. Further, at high salt condition, Greek key type quadruplex structures are energetically comparable with hairpin dimer and B-DNA type duplex structures. All tetrads in the quadruplex structures are well stacked and provide favourable stacking energy values. Interestingly, in the energy minimized hairpin dimer and Greek key type quadruplex structures, all the bases even in the non-G tetrads are cyclically hydrogen bonded, even though the A, C and T-tetrads were not hydrogen bonded in the starting structures.

A Genetic Study of Immunoglobulin E and Atopic Disease Based on Families Ascertained through Asthmatic Children

In order to investigate the modes of inheritance of serum immunoglobulin E (IgE) levels and atopic disease, serum IgE levels and data on allergic disease were obtained from 42 families ascertained through asthmatic children visiting an allergy clinic. Although the mean IgE levels were elevated (mean 637 U/ml), the prevalence of atopic disease in this population was surprisingly low. When the data were analyzed using complex segregation analysis, no major locus could be detected. Moreover, the polygenic heritability was unexpectedly small even though the correlation between serum IgE levels and the liability to atopic disease was around 0.4. Given this unusual set of findings, it is postulated that parasitic infections in this population have (in accordance with well-established results of parasitic disease) caused both elevated levels of serum IgE and a decreased prevalence of allergic disease with the possible masking of the various genetic components of serum IgE levels and atopic disease.

Characterization and immune response of a protein produced by a cDNA clone of foot and mouth disease virus, type Asia 1 63/72

A 0.9 kb double stranded cDNA of foot and mouth disease virus (FMDV) Type Asia 1, 63/72 was cloned in an expression vector, pUR222. A protein of 38 kd was produced by the clone which reacted with the antibodies raised against the virus. A 20 kd protein which may be derived from the 38 kd protein contained the antigenic epitopes of the protein VP1 of the virus. Injection of 10-20 micrograms of the partially purified 38 and 20 kd proteins or a lysate of cells containing 240 micrograms of the proteins elicited high titers of FMDV specific antibodies in guinea pigs and cattle respectively. Also, at these concentrations, the proteins protected 5 of 8 guinea pigs and 3 of 8 cattle when challenged with a virulent virus.

Hemiorchidectomy leads to dramatic and immediate alterations in pituitary follicle-stimulating hormone secretion and the functional activity of the remaining testis in the adult male bonnet monkey (Macaca radiata)

The aim of the present study was to examine the effect of hemiorchidectomy (HO) on serum FSH, LH, testosterone (T), and inhibin (INH) concentrations as well as on the testicular volume (TV) and on changes in the kinetics of germ cell turnovers in the remaining testis of adult male bonnet monkeys. Blood samples collected at 2200 h at various times before and after HO and testicular biopsies obtained at different periods were subjected to hormone analysis and DNA flow cytometry. Though serum T levels were lowered (p < 0.05) at 12 h after HO, T levels rapidly returned to intact control concentrations by Day 5. While serum LH remained unaltered, serum FSH increased markedly within 2 days of HO and remained significantly (p < 0.05) elevated over the next 90 days. Though serum INH showed a significant decrease (p < 0.05) by 15 min of HO, it returned to approximately 80% of intact levels within one week. The TV of the remaining testis showed maximal increment by Day 30 (p < 0.05) of HO. DNA flow cytometric analysis 24 days after HO showed increases (p < 0.05) in spermatogonia (2C) and primary spermatocytes (4C). These cell types by Day 45 had transformed to round (1C) and elongate (HC) (by 38%, p < 0.001) spermatids. Overall spermatogenesis (conversion of 2C to 1C and HC) showed significant enhancement at Days 110 and 175, suggesting that the spurt in spermatogenic activity is not confined to a single spermatogenic cycle.

Impaired conflict monitoring in Parkinson's disease patients during an oculomotor redirect task

Fallibility is inherent in human cognition and so a system that will monitor performance is indispensable. While behavioral evidence for such a system derives from the finding that subjects slow down after trials that are likely to produce errors, the neural and behavioral characterization that enables such control is incomplete. Here, we report a specific role for dopamine/basal ganglia in response conflict by accessing deficits in performance monitoring in patients with Parkinson's disease. To characterize such a deficit, we used a modification of the oculomotor countermanding task to show that slowing down of responses that generate robust response conflict, and not post-error per se, is deficient in Parkinson's disease patients. Poor performance adjustment could be either due to impaired ability to slow RT subsequent to conflicts or due to impaired response conflict recognition. If the latter hypothesis was true, then PD subjects should show evidence of impaired error detection/correction, which was found to be the case. These results make a strong case for impaired performance monitoring in Parkinson's patients.

Ring Resonators and Micro Fluidics: Novel Design for Drug/Disease Detection

MEMS systems are technologically developed from integrated circuit industry to create miniature sensors and actuators. Originally these semiconductor processes and materials were used to build electrical and mechanical systems, but expanded to include biological, optical fluidic magnetic and other systems 12]. Here a novel approach is suggested where in two different fields are integrated via moems, micro fluidics and ring resonators. It is well known at any preliminary stage of disease onset, many physiological changes occur in the body fluids like saliva, blood, urine etc. The drawback till now was that current calibrations are not sensitive enough to detect the minor physiological changes. This is overcome using optical detector techniques 1]. The basic concepts of ring resonators, with slight variations can be used for optical detection of these minute disease markers. A well known fact of ring resonators is that a change in refractive index will trigger a shift in the resonant wavelength 5]. The trigger for the wavelength shift in the case discussed will be the presence of disease agents. To trap the disease agents specific antibody has to be used (e. g. BSA).

Testis-specific histone (H1t) is not phosphorylated and has a weak interaction with chromatin

Soluble chromatin was prepared from rat testes after a brief micrococcal nuclease digestion. After adsorption onto hydroxylapatite at low ionic strength, the histone Hl subtypes were eluted with a shallow salt gradient of 0.3 M NaCl to 0.7 M NaCl. Histone Hlt was eluted at 0.4 MNaCl, while histones H1a and Hlc were eluted at 0.43 M NaCl and 0.45 M respectively. The extreme divergence of the amino acid sequence of the C-terminal half of histone Hlt, the major DNA binding domain of histone Hl, from that of the somatic consensus sequence may contribute to the weaker interaction of histone Hlt with the rat testis chromatin. Further, histone Hlt was not phosphorylated in vivo in contrast to histone Hla and Hlc, as is evident from the observation that histone Hlt lacks the SPKK motif recognized by the CDC-2kinase or the RR/KXS motif recognized by protein kinase A.

A method for in vivo [32P]phosphate labelling of testis proteins

The direct intratesticular injection of [P-32]phosphate resulted in 4-9 times more labelling of rat testis proteins compared to the conventional method of in vitro incubation. Moreover this is a simple technique requiring minimum (7-10 times less) radioactive phosphate and is less hazardous.

Evidence for follicle-stimulating hormone mediation in the hemiorchidectomy-induced compensatory increase in the function of the remaining testis of the adult male bonnet monkey (Macaca radiata)

Hemiorchidectomy (HO) in the adult male bonnet monkey results in a selective increase in circulating concentrations of FSH and testosterone, and this is accompanied by compensatory increase in sperm production by the remaining testis. We investigated the possible role of increased FSH concentration that occurs after HO in the compensatory increase in the activity of the remaining testis. Of eight adult male bonnet monkeys that underwent HO, four received i.v. injections every other day for 30 days of a well-characterized ovine FSH antiserum (a/s) that cross-reacts with monkey FSH. The remaining four males received normal monkey serum (NMS) as control treatment in a protocol similar to that employed for ais-treated males. Blood samples were collected between 2100 and 2200 h before and 1/2, 1, 3, 5, 7, 14, 22, and 29 days after HO. Testicular weight, number of 3 beta-hydroxy steroid dehydrogenase-positive (3 beta-HSD+) cells, and DNA flow cytometric analysis of germ cell populations were obtained for testes collected before and at the termination of NMS or ais treatment. In NMS-treated males, circulating serum FSH concentrations progressively increased to reach a maximal level by Day 7 after HO (1.95 +/- 0.3 vs. 5.6 +/- 0.7 ng/ml on Days -1 and 7, respectively). Within 30 min of ais injection, FSH antibodies were detected in circulation, and the antibody level was maintained at a constant level between Day 7 and end of treatment (exhibiting 50-60% binding to I-125-hFSH). Although circulating mean nocturnal serum testosterone concentration showed an initial decrease, it rose gradually to pre-HO concentrations by Day 7 in NMS-treated males. In contrast, nocturnal mat serum testosterone concentrations in a/s-treated males remained lower than in NMS-treated controls (p < 0.05) up to Day 22 and thereafter only marginally increased. Testicular weights increased (p < 0.05) over the pre-HO weight in NMS- but not in ais-treated males. After HO, the number of 3 beta-HSD+ cells (Leydig cells) was markedly increased but was significantly (p < 0.05) higher in NMS-treated males compared to a/s-treated males. A significant (p < 0.05) reduction in the primary spermatocyte population of germ cells was observed in ais-treated compared to NMS-treated males. These results suggest that the increased FSH occurring after HO could be intimately involved in increasing the compensatory functional activity of the remaining testis in the male bonnet monkey.

Selective immunoneutralization of luteinizing hormone results in the apoptotic cell death of pachytene spermatocytes and spermatids in the rat testis

The selective withdrawal of pituitary gonadotropins through specific antibodies is known to cause disruption of spermatogenesis. The cellular mechanism responsible for the degenerative changes under isolated effect of luteinizing hormone (LH) deprivation is not clear. Using antibodies specific to LH we have investigated the effect of immunoneutralization of LH on apoptotic cell death in the testicular cells of the immature and the adult rats. Specific neutralization of LH resulted in apoptotic cell death of germ cells, both in the immature and the adult rats. The germ cells from control animals showed predominantly high molecular weight DNA, while the antiserum treated group showed DNA cleavage into low molecular weight DNA ladder characteristic of apoptosis. This pattern could be observed within 24 h of a/s administration and the effect could be reversed by testosterone. The germ cells were purified by centrifugal elutriation and the vulnerability of germ cell types to undergo apoptosis under LH deprivation was investigated. The round spermatids and the pachytene spermatocytes were found to be the most sensitive germ cells to lack of LH and underwent apoptosis. Interestingly, spermatogonial cells were found to be the least sensitive germ cells to the lack of LH in terms of apoptotic cell death. Results show that LH, in addition to being involved in the germ cell differentiation, is also involved in cell survival and prevent degeneration of germ cells during spermatogenesis. Apoptotic DNA fragmentation may serve as a useful marker for the study of hormonal regulation of spermatogenesis and the specific neutralization of gonadotropic hormones can be a reliable model for the study of the molecular mechanism of apoptosis.

Interaction of A beta peptide (1-40) with amino acid aluminium complexes: relevance to Alzheimer's disease

A beta (39-43 aminoacid residues) is the principal peptide component of amyloid deposits in Alzheimer's disease (AD). A beta peptide is derived from the amyloid precursor protein (APP) in which mutations give rise to many forms of familial AD. Aluminium is reported to play a key role in inducing conformational change in the synthetic beta-amyloid peptide (1-40)from alpha-helix to beta-pleated sheet, leading to aggregation and fibrillar formation. We have studied the interaction of amino acid-Al complexes such as D-Asp-Al and L-Glu-Al with A beta(1-40) in TFE/buffer (70% TFE and 30% H2O v/v pH 6.7) mixture using CD spectroscopy. The interaction of either of these amino acid complexes with A beta(1-40) results in loss of alpha-helical content and the peptide is more unstructured compared to free Al3+ in the solution. Our data strongly support the idea, that the Al3+ in the form of aminoacid-Al complexes is more effective in inducing random coil conformation in the A beta peptide than the free Al3+ present in the solution.

Major depression with ischemic heart disease: Effects of paroxetine and nortriptyline on measures of nonlinearity and chaos of heart rate

Depression is associated with increased cardiovascular mortality in patients with preexisting cardiac illness. A decrease in cardiac vagal function as suggested by a decrease in heart rate variability (HRV) or heart period variability has been linked to sudden death in patients with cardiac disease as well as in normal controls. Recent studies have shown decreased vagal function in cardiac patients with depression as well as in depressed patients without cardiac illness. In this study, we compared 20 h awake and sleep heart period nonlinear measures using quantification of nonlinearity and chaos in two groups of patients with major depression and ischemic heart disease (mean age 59-60 years) before and after 6 weeks of treatment with paroxetine or nortriptyline. Patients received paroxetine, 20-30 mg/day or nortriptyline targeted to 190-570 nmol/l for 6 weeks. For HRV analysis, 24 patients were included in the paroxetine treatment study and 20 patients in the nortriptyline study who had at least 20,000 s of awake data. The ages of these groups were 60.4 +/- 10.5 years for paroxetine and 60.8 +/- 13.4 years for nortriptyline. There was a significant decrease in the largest Lyapunov exponent (LLE) after treatment with nortriptyline but not paroxetine. There were also significant decreases in nonlinearity scores on S-netPR and S-netGS after nortriptyline, which may be due to a decrease in cardiac vagal modulation of HRV. S-netGS and awake LLE were the most significant variables that contributed to the discrimination of postparoxetine and postnortriptyline groups even with the inclusion of time and frequency domain measures. These findings suggest that nortriptyline decreases the measures of chaos probably through its stronger vagolytic effects on cardiac autonomic function compared with paroxetine, which is in agreement with previous clinical and preclinical reports. Nortriptyline was also associated with a significant decrease in nonlinearity scores, which may be due to anticholinergic and/or sympatholytic effects. As depression is associated with a strong risk factor for cardiovascular mortality, one should be careful about using any drug that adversely affects cardiac vagal function. Copyright (C) 2002 S. Karger AG, Basel.