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Biomedical subjects

A Desai

Publications and source records attributed to A Desai.

At least 19 recordsLinked to original sources
PubMed2001

Functional analysis of kinetochore assembly in Caenorhabditis elegans.

In all eukaryotes, segregation of mitotic chromosomes requires their interaction with spindle microtubules. To dissect this interaction, we use live and fixed assays in the one-cell stage Caenorhabditis elegans embryo. We compare the consequences of depleting homologues of the centromeric histone CENP-A, the kinetochore structural component CENP-C, and the chromosomal passenger protein INCENP. Depletion of either CeCENP-A or CeCENP-C results in an identical "kinetochore null" phenotype, characterized by complete failure of mitotic chromosome segregation as well as failure to recruit other kinetochore components and to assemble a mechanically stable spindle. The similarity of their depletion phenotypes, combined with a requirement for CeCENP-A to localize CeCENP-C but not vice versa, suggest that a key step in kinetochore assembly is the recruitment of CENP-C by CENP-A-containing chromatin. Parallel analysis of CeINCENP-depleted embryos revealed mitotic chromosome segregation defects different from those observed in the absence of CeCENP-A/C. Defects are observed before and during anaphase, but the chromatin separates into two equivalently sized masses. Mechanically stable spindles assemble that show defects later in anaphase and telophase. Furthermore, kinetochore assembly and the recruitment of CeINCENP to chromosomes are independent. These results suggest distinct roles for the kinetochore and the chromosomal passengers in mitotic chromosome segregation.

Animals↗
PubMed2001

Pemphigus vulgaris: the role of IL-1 and IL-1 receptor antagonist in pathogenesis and effects of intravenous immunoglobulin on their production.

Intravenous immunoglobulin (IVIG) is increasingly being used for the treatment of autoimmune diseases. In the present report, the role of IVIG on in vivo and in vitro production of IL-1 and IL-1 receptor antagonist (Ra) was studied in patients with pemphigus vulgaris (PV). Serum samples from 20 untreated patients with active PV prior to initiation of systemic therapy, 20 patients receiving IVIG treatment, 20 patients in clinical remission after conventional therapy, and 20 normal human controls were studied to determine the serum levels of IL-1alpha, IL-1beta, and IL-1Ra. The in vitro production of these cytokines was measured in the culture supernatant of peripheral blood mononuclear cells (PBMC) from 10 PV patients immediately before and after IVIG therapy and from age and sex-matched 10 healthy donors simultaneously. Elevated levels of IL-1alpha and IL-1beta were detected (i) in the serum of untreated PV patients with active disease prior to systemic therapy and (ii) before IVIG infusions in patients receiving IVIG therapy. These increased levels are statistically significant when compared to the levels in healthy controls (P < 0.01). A marked reduction of IL-1alpha and IL-1beta was detected (i) in the serum of patients in prolonged clinical remission and (ii) immediately after IVIG infusion in those patients on IVIG therapy. Increased level of IL-1Ra was detected in PV patients in prolonged clinical remission and after IVIG infusion in those receiving IVIG therapy. These differences were statistically significant when compared to the levels in normal controls and to the levels in the sera of patients with active disease (P < 0.01) or just before the beginning of IVIG infusion (P < 0.01). Similar differences in the levels of IL-1alpha, IL-1beta, and IL-1Ra were found in the culture supernatant of PBMC isolated from the PV patients pre and post IVIG therapy. These observations suggests that, compared to normal controls, patients with active PV have reversed levels of IL-1alpha, IL-1beta, and IL-1Ra. IVIG therapy may down-regulate production of IL-1alpha and IL-1beta and enhance production of IL-1Ra, in vivo and in vitro. This might be one of the important mechanisms by which IVIG produces its early therapeutic effects in pemphigus vulgaris.

Humans↗
PubMed2001

Homocysteine augments cytokine-induced chemokine expression in human vascular smooth muscle cells: implications for atherogenesis.

Hyperhomocysteinemia is an independent risk factor for atherosclerosis and atherothrombosis. While in vitro studies have revealed a number of homocysteine-mediated alterations in the thromboregulatory properties of endothelial cells, comparatively little is known about homocysteine-modulated smooth muscle cell function. We observed that exposure of human aortic smooth muscle cells to pathophysiologically relevant concentrations of homocysteine results in concentration-dependent increases in cytokine-induced MCP-1 and IL-8 secretion. RNase protection assays revealed that both MCP-1 and IL-8 mRNA concentrations are increased in homocysteine-treated smooth muscle cells when compared to cells activated with cytokines alone. Homocysteine treatment also increased cytosolic-to-nuclear translocation of the p65 and p50 subunits of the Rel/NF-kappaB family of transcription factors but had no effect on AP-1 activation. Cumulatively, these data suggest that homocysteine may increase monocyte recruitment into developing atherosclerotic lesions by upregulating MCP-1 and IL-8 expression in vascular smooth muscle cells.

Arteriosclerosis↗
PubMed2001

The spindle: a dynamic assembly of microtubules and motors.

In all eukaryotes, a microtubule-based structure known as the spindle is responsible for accurate chromosome segregation during cell division. Spindle assembly and function require localized regulation of microtubule dynamics and the activity of a variety of microtubule-based motor proteins. Recent work has begun to uncover the molecular mechanisms that underpin this process. Here we describe the structural and dynamic properties of the spindle, and introduce the current concepts regarding how a bipolar spindle is assembled and how it functions to segregate chromosomes.

Animals↗
PubMed2001

The degree of attenuation of tick-borne encephalitis virus depends on the cumulative effects of point mutations.

An infectious clone (pGGVs) of the tick-borne encephalitis complex virus Vasilchenko (Vs) was constructed previously. Virus recovered from pGGVs produced slightly smaller plaques than the Vs parental virus. Sequence analysis demonstrated five nucleotide differences between the original Vs virus and pGGVs; four of these mutations resulted in amino acid substitutions, while the fifth mutation was located in the 3' untranslated region (3'UTR). Two mutations were located in conserved regions and three mutations were located in variable regions of the virus genome. Reverse substitutions from the conserved regions of the genome, R(496)-->H in the envelope (E) gene and C(10884)-->T in the 3'UTR, were introduced both separately and together into the infectious clone and their biological effect on virus phenotype was evaluated. The engineered viruses with R(496) in the E protein produced plaques of smaller size than viruses with H(496) at this position. This mutation also affected the growth and neuroinvasiveness of the virus. In contrast, the consequence of a T(10884)-->C substitution within the 3'UTR was noticeable only in cytotoxicity and neuroinvasiveness tests. However, all virus mutants engineered by modification of the infectious clone, including one with two wild-type mutations, H(496) and T(10884), showed reduced neuroinvasiveness in comparison with the Vs parental virus. Therefore, although the H(496)-->R and T(10884)-->C substitutions clearly reduce virus virulence, the other mutations within the variable regions of the capsid (I(45)-->F) and the NS5 (T(2688)-->A and M(3385)-->I) genes also contribute to the process of attenuation. In terms of developing flavivirus vaccines, the impact of accumulating apparently minor mutations should be assessed in detail.

3' Untranslated Regions↗
PubMed2001

Review of rivastigmine and its clinical applications in Alzheimer's disease and related disorders.

Rivastigmine (Exelontrade mark, Novartis) is a novel intermediate-acting reversible and non-competitive carbamate acetylcholinesterase (AChE) that was recently introduced for the treatment of Alzheimer's disease (AD). Preclinical studies have shown that rivastigmine has many similarities to other currently available cholinesterase inhibitors (ChEIs) and some important differences. The drug has been evaluated for this use in two well designed, published, adequately powered, Phase III, 26 week clinical trials that included a total of more than 1500 rivastigmine and 700 placebo recipients. Most of these patients had concomitant disorders that were being treated with numerous other drugs. These studies indicate that rivastigmine (6 - 12 mg/day) usually produces cognitive, global and functional changes that indicate significantly less deterioration than was observed with placebo in patients with mild-to-moderate AD, with higher doses producing more benefits. Rivastigmine is beneficial in all three domains (namely cognition, daily activities and behaviour) of AD. Data on long-term efficacy support continued benefits of rivastigmine beyond 6 months. Rivastigmine is generally well-tolerated with no requirement for routine electrocardiogram (ECG) or blood monitoring. Rivastigmine causes adverse events that are generally those expected from a ChEI and mainly involve gastrointestinal system. They are usually mild-to-moderate, of short duration and responsive to dosage reduction. They occur mostly during the dosage titration phase and decrease during the maintenance phase. Clinically significant drug-drug interactions are unlikely. The consistent efficacy in treating all three domains (cognition, daily functioning and behaviour) and good tolerability, particularly with slow titration, makes rivastigmine a good first-line ChEI therapy for the treatment of AD. Therapeutic dose range is 6 - 12 mg/day. Rivastigmine should be started at 1.5 mg b.i.d. with meals and increased at 2 - 4 week intervals to achieve the highest tolerated dose.

Alzheimer Disease↗
PubMed2001

Evaluation of efficacy and safety of iron polymaltose complex and folic acid (Mumfer) vs iron formulation (ferrous fumarate) in female patients with anaemia.

Treatment of iron deficiency anaemia with conventional oral preparations is handicapped by unpredictable haematological response in addition to potential for irritating gastrointestinal adverse events. Iron polymaltose complex (IPC), a novel oral iron formulation with better absorbability, predictable haematinic response and less side effects was compared with oral ferrous fumarate in 100 female patients with documented iron deficiency anaemia. Clinical parameters (pallor, weakness) as well as biochemical parameters (Hb, serum iron, total iron binding capacity) show favourable changes with IPC; the physician and patient assessment also favour IPC over ferrous fumarate.

Adult↗
PubMed2001

Efficacy and safety of Ascoril in the management of cough--National Study Group report.

A total of 768 patients were recruited by 81 physicians and paediatricians all over the country in this National Study Group of 'Ascoril + Expectorant'. The results of this first large scale study of a cough formula indicates that 'Ascoril + Expectorant' is effective in controlling cough, breathlessness and decreasing the volume of sputum. No serious adverse events were noted. Ascoril was well accepted by the patients and its efficacy was rated very high by the physician. The National Study Group concludes that 'Ascoril + Expectorant' is highly effective in the management of cough associated with lower respiratory tract infection and COPDs.

Adolescent↗
PubMed2000

Kinetochores.

Explore the source record for details and available documents.

Animals↗
PubMed2000

A micromachined chip-based electrospray source for mass spectrometry.

A micromachining process is described for fabricating a mass spectrometry electrospray source on a silicon chip. The process utilizes polymer (parylene) layers to form a system of chambers, filters, channels, and hollow needle structures (electrospray emitters) that extend more than a millimeter beyond the edge of the silicon substrate. The use of photoresist as the sacrificial layer facilitates the creation of long channels. Access to the channel structures on the chip is through a port etched through the silicon substrate that also serves as a sample reservoir. A reusable chip holder consisting of two plastic plates and an elastomer gasket provides the means to mount the chip in front of the mass spectrometer inlet and make electrical and gas connections. The electrospray emitters have tapered tips with 5 microns x 10 microns rectangular openings. The shape of the tip can be varied depending on the shape of the mask used to protect the parylene structures during the final plasma etch. The parylene emitters are physically robust and require only a high electric field to achieve stable electrospray operation over a period of a few hours. Direct comparisons with conventional glass or fused silica emitters indicated very similar performance with respect to signal strength and stability, spectral quality, and endurance. The automated MS/MS analysis of a mixture of tryptic peptides was no more difficult and yielded nearly identical results as the analysis of the same sample using a conventional nanospray device. This work demonstrates that an efficient electrospray interface to mass spectrometry can be integrated with other on-chip structures and mass-produced using a batch process.

Mass Spectrometry↗
PubMed2000

Reversal of the antiinflammatory effects of methotrexate by the nonselective adenosine receptor antagonists theophylline and caffeine: evidence that the antiinflammatory effects of methotrexate are mediated via multiple adenosine receptors in rat adjuvant arthritis.

OBJECTIVE: Weekly low-dose methotrexate (MTX) remains the mainstay of second-line therapy for rheumatoid arthritis (RA). We have previously reported that adenosine, acting at specific receptors on inflammatory cells, mediates the antiinflammatory effects of MTX in both in vitro and in vivo models of acute inflammation, but the mechanism by which MTX suppresses the chronic inflammation of arthritis remains controversial. The present study was undertaken to further investigate the means by which adenosine mediates the antiinflammatory effects of MTX. METHODS: The effects of 2 nonselective adenosine receptor antagonists, theophylline and caffeine, were examined, using the rat adjuvant arthritis model of RA. These agents were given alone and in conjunction with MTX, and arthritis severity was assessed clinically, radiologically, and histologically. Since rodent adenosine A3 receptors are not blocked by theophylline, selective A1, A2A, and A2B receptor antagonists were tested as well. RESULTS: Control animals developed severe arthritis, which was markedly attenuated by weekly treatment with MTX (0.75 mg/kg/week). Neither theophylline alone nor caffeine alone (each at 10 mg/kg/day) significantly affected the severity of the arthritis, but both agents markedly reversed the effect of MTX as measured by a severity index, hindpaw swelling, and hindpaw ankylosis. Radiographic and histologic analyses confirmed these observations. Neither A1, A2A, nor A2B receptor antagonists affected the capacity of MTX to ameliorate inflammation in adjuvant arthritis. CONCLUSION: These results provide strong evidence that adenosine mediates the antiinflammatory effects of MTX in this model of RA. Moreover, the findings suggest that abstinence from caffeine, a ubiquitous food additive and medication, may enhance the therapeutic effects of MTX in RA.

Animals↗
PubMed2000

Loxosceles deserta spider venom induces the expression of vascular endothelial growth factor (VEGF) in keratinocytes.

Evenomation by arachnids of the genus Loxosceles frequently results in disfiguring necrotic skin lesions. The cellular and molecular mechanisms which contribute to lesion development are incompletely defined but appear to involve participation of several pro-inflammatory mediators. We have recently observed that Loxosceles deserta venom induces the production of chemokines in human umbilical vein endothelial cells (HUVECs) and human pulmonary epithelial cells. In the present study we observed that Loxosceles deserta venom induces the expression of vascular endothelial growth factor (VEGF) in human keratinocytes but little in smooth muscle cells and none in pulmonary epithelial cells. A potent endothelial cell-specific mitogen, VEGF induces angiogenesis and vascular permeability in vivo. RNase protection assay data indicate that VEGF mRNA concentrations in keratinocytes are significantly increased at 2 h following venom exposure. These data suggest that keratinocyte-derived VEGF may contribute to the vasodilation, edema and erythema which occur following Loxosceles evenomation.

Aorta↗
PubMed2000

HIV antibody profiles in serum and CSF of patients with neurological disease can serve as predictors of outcome.

The serum and CSF antibody profiles were investigated in 100 patients with HIV in relation to the type and severity of neurological disease. Among them, 87 were positive for anti-HIV antibodies in the CSF. In 30 of 87 patients detailed analysis by western blot could be performed. In 20 of 30 the profiles were dissimilar, with more of bands being found in the serum than in the CSF. The correlation of western blot profiles to the clinical outcome indicated that the number of anti-HIV antibody bands as well as the index in the CSF of fatal cases were significantly less compared with non-fatal cases (p=0.019 and p=0.039 respectively).

Adolescent↗
PubMed2000

Hürthle cell adenoma diagnosed by core needle biopsy in a male patient.

Hürthle cell adenomas (HCAs) are a rare and potentially lethal variant of follicular tumors of the thyroid. Considerable controversy exists regarding potential risk factors, diagnosis, and treatment of HCAs. The authors report the case of a 38-year-old male patient with an 8.3 cm x 3.5 cm HCA. Diagnosis was made preoperatively from a core needle biopsy and confirmed postoperatively on frozen section. Treatment consisted of a right lobectomy.

Adenoma, Oxyphilic↗
PubMed2000

Profile of neurologic disorders associated with HIV/AIDS from Bangalore, south India (1989-96).

One hundred patients (95 males, 5 females, mean age at presentation 31.6 +/- 9.4 yr) with various neurological disorders associated with HIV infection during 1989-1996 were evaluated at NIMHANS, Bangalore. Eighty patients belonged to group I associated with opportunistic neuroinfections and 20 to group II--non infectious neurological disorders. Cryptococcal meningitis either alone (n = 31) or associated with tuberculous meningitis (n = 6) was the most common (46.3%) followed by neurotuberculosis either alone (n = 24) or with cerebral toxoplasmosis (n = 4) accounting for 35 per cent. Other opportunistic neuroinfections included cerebral toxoplasmosis, herpes zoster, fulminant pyogenic meningitis and neurosyphilis. Clinical characteristics, diagnostic clues, their laboratory and radiological profiles and problems encountered in diagnosis and management of these opportunistic infections are highlighted. In group II (19 males and one female; mean age of 32.6 +/- 9.4 yr), two patients had cortical dementia, three acute brain stem involvement, two epilepsy and one had features suggestive of progressive multifocal leukoencephalopathy. Two patients of group I during follow up developed cortical dementia. Six had peripheral nervous system involvement similar to Guillain-Barre syndrome. Sixty six patients (63 of group I and 3 of group II) progressed to AIDS, 33 patients from group I and one patient from group II succumbed to the disease. With the rapid increase in the incidence of HIV/AIDS and an increase in the neurological manifestations of HIV/AIDS it is important to recognise the magnitude of the problem for health planning in India.

AIDS-Related Opportunistic Infections↗
PubMed2000

Efficacy and safety of Ascoril expectorant and other cough formula in the treatment of cough management in paediatric and adult patients--a randomised double-blind comparative trial.

The present study was undertaken to study the comparative safety and efficacy of two cough formulas viz, Ascoril expectorant and other cough formula in the management of cough associated with respiratory disorders. Fifty patients having cough associated with various respiratory disorders like bronchitis and upper or lower respiratory tract infections were randomly divided into 2 equal groups and were treated with one of the two cough formulas viz, Ascoril cough formula and other cough formula in double-blind manner over a period of 15 days. The evaluation of improvement was carried out by a rating scale using three clinical parameters--cough, sputum and breathlessness. The physicians were asked to rate the effectiveness of the therapy and patients were asked to rate the acceptability of therapy using pre-defined operational criteria. It was observed that the improvement and symptom relief was almost immediate, quicker and better in the group receiving Ascoril as compared to other group. On effectiveness parameter, 96% of the physicians rated Ascoril as having either 'very high effectiveness or high effectiveness' as opposed to only 34% of the physicians who rated other cough formula as having 'high' or 'very high effectiveness'. While on parameter of acceptability, 96% of the patients rated acceptability of Ascoril as 'high' or 'good' as opposed to only 24% of the patients who rated other cough formula 'high' or 'good'. The findings of this study suggests that Ascoril cough formula has better efficacy as well as better patient acceptability. Thus, Ascoril cough formula is superior to other cough formula in management of cough associated with respiratory disorders.

Adolescent↗
PubMed2000

Evaluation of safety and efficacy of supirocin-B (mupirocin 2% + betamethasone dipropionate 0.05%) in infected dermatoses--a post marketing study.

The aim of the present post marketing study was to study the safety and efficacy of supirocin-B ointment (mupirocin 2% + betamethasone dipropionate 0.05%) in the treatment of infected dermatoses. For this purpose physicians from different parts of India were requested to keep the clinical records prospectively as per a specially designed proforma over a follow-up period of 7 days, whenever they prescribed supirocin-B ointment (mupirocin 2% + betamethasone dipropionate 0.05%) for local application, three times a day, to their patients having either primary infection complicated by dermatoses or dermatoses infected secondarily. From the analysis of 251 clinical records contributed by 27 physicians, it was evident that in clinical practice, supirocin-B ointment (mupirocin 2% + betamethasone dipropionate 0.05%) was found to be safe and very effective by physicians in the treatment of infected dermatoses in 94.8% of the patients. Similarly 92.4% of the patients reported more than 70% improvement in their symptoms after 7 days of treatment. No adverse effects were reported during the treatment period by any of the patients except worsening of skin lesions by one patient. Thus from this study, supirocin-B ointment (mupirocin 2% + betamethasone dipropionate 0.05%) seems to be safe and effective in the treatment of infected dermatoses.

Betamethasone↗