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Biomedical subjects

R Kaur

Publications and source records attributed to R Kaur.

At least 37 records · Page 2Linked to original sources
PubMed2001

Candidemia in neonatal intensive care unit.

The present study was conducted over a period of 6 months to determine the Candida species causing candidemia in a neonatal intensive care unit and to analyse the risk factors associated with acquisition of significant fungemia. Speciation of the 19 isolated Candida spp was done by the standard techniques. Antimicrobial susceptibility of these isolates was determined by disc diffusion method against Amphotericin B, Fluconazole, Ketoconozole and 5-Flucytosine. Candida glabrata was the most common species involved (42.1%). Other species isolated were C. tropicalis (31.6%). Calbicans (21.1%) and C.parapsilosis (5.2%). All the isolates were sensitive to Amphotericin B. Resistance to other antigungal agents was seen only in C. globrata. Significant candidemia was seen in 14/19 (72.6%) of neonates. Risk factors found to be associated with significant candidemis in these neonates included intake of multiple broad-spectrum antibiotics (p<0.0001), use of total parenteral nutrition (p<0.045) and ventilators (p<0.0001).

Amphotericin B↗
PubMed2000

Antagonist effects on human P2X(7) receptor-mediated cellular accumulation of YO-PRO-1.

We have examined the interaction of P2 antagonists with the human P2X(7) receptor by studying their effect on 2' and 3'-O-benzoyl-benzoyl-ATP (DbATP) stimulated cellular accumulation of the fluorescent, DNA binding dye, YO-PRO-1 (MW=375Da). In suspensions of HEK293 cells expressing human recombinant P2X(7) receptors, DbATP produced time and concentration-dependent increases in YO-PRO-1 fluorescence. This response presumably reflects YO-PRO-1 entry through P2X(7) receptor channels and binding to nucleic acids. When studies were performed in a NaCl-free, sucrose-containing buffer, full concentration-effect curves to DbATP could be constructed. The P2 antagonists, pyridoxalphosphate-6-azophenyl-2', 4'-disulphonic acid (PPADS) and periodate oxidized ATP (oATP), reduced the potency of DbATP and decreased its maximum response. 1-[N,O-bis(1, 5-isoquinolinesulphonyl)-N-methyl-L-tyrosyl]-4-phenylpiperazine (KN62) and its analogue, KN04, reduced the potency of DbATP. Schild slopes for KN62 and KN04 were shallow and exhibited a plateau at concentrations of compound greater than 1 microM, indicating that these compounds were not competitive antagonists. Calmidazolium and a monoclonal antibody to human P2X(7) receptors attenuated DbATP-stimulated YO-PRO-1 accumulation but they were not competitive antagonists and only produced 2 - 3 fold decreases in the potency of DbATP. The effects of PPADS and KN62 were partially reversible whereas those of oATP were not. PPADS protected cells against the irreversible antagonist effects of oATP suggesting a common site of action. In contrast KN62 was not effective suggesting that it may bind at a different site to oATP and PPADS. This study has demonstrated that P2X(7) receptor function can be quantified by measuring DbATP stimulated YO-PRO-1 accumulation and has provided additional information about the interaction of P2 receptor antagonists with the human P2X(7) receptor.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed2000

The 'consciousness primitive': a competence model of mind and will.

Questions about mind and will are usually raised as though mind and will are either present or absent. Here, a view is presented to suggest that they are only a particular instantiation of a 'consciousness primitive', present in lower animals as well as in primitive portions of the human brain. Physiological variables, drugs and transmitters alter it in order to produce discontinuous products, such as learning, motivation, emotions etc., which are usually studied by performance models as though they are distinctive functions of the brain.

Animals↗
PubMed2000

High-resolution CT in renal transplant patients with suspected pulmonary infections.

OBJECTIVE: This prospective study was carried out to assess the usefulness of high-resolution CT (HRCT) of the chest in immunocompromised renal transplant patients with suspected pulmonary infections. MATERIAL AND METHODS: Twenty-one consecutive renal transplant patients with clinically suspected pulmonary infections underwent chest radiography, HRCT and other tests including bronchoalveolar lavage (BAL). HRCT was performed using a high spatial frequency algorithm with 2-mm-thick sections at 10-mm intervals from apices to domes of the diaphragm. The findings on chest radiography and HRCT were interpreted by two thoracic radiologists and the usefulness of HRCT was evaluated. The images were interpreted independently by two radiologists, who were blinded to the findings of other imaging modalities and the final diagnosis. Any differences regarding the imaging findings were resolved through consensus. RESULTS: Final diagnosis was obtained in 17 patients, and no cause for symptomatology was established in 4 patients. The spectrum of infections included pulmonary tuberculosis (TB) in 11 patients, cytomegalovirus pneumonia (CMV) in 2 patients, cryptococcal and streptococcal pneumonia, pulmonary aspergillosis and esophageal candidiasis in 1 patient each. Compared to chest radiography, HRCT revealed additional findings in 11 patients. HRCT findings were suggestive of underlying infection in 11 patients. The final diagnosis coincided with HRCT diagnosis in all but 1 patient. HRCT findings were non-specific in 3 patients and normal in 7. The findings were concordant in 19 cases. The results were not in agreement in only 2 cases. CONCLUSION: HRCT can provide useful information and suggest the diagnosis in a significant proportion of renal transplant patients with pulmonary infection.

Adult↗
PubMed2000

Effects of dietary selenium (SE) on morphology of testis and cauda epididymis in rats.

Selenium is an essential micronutrient for animals. To determine whether its excess in diet induces morphological changes within the male reproductive system, a detailed qualitative and quantitative evaluation of the changes in the histology of the testis and cauda epididymis was undertaken in male rats. Adult male albino rats were fed 6 and 8 ppm Se in diet for 6 and 9 weeks. Each male consuming 6 ppm Se was mated with two untreated females, their offsprings were allowed to mature upto 12 weeks of age. The testes and cauda epididymes of male rats were prepared for light microscopy. Excess of dietary Se caused dose-time-dependent reduction in body weight and reproductive organ weights but increase in number of morphologically abnormal spermatozoa. Histopathological studies of the testes and cauda epididymis have revealed that Se-rich diets cause dose-time-dependent reduction in tubular diameter, epithelial height, number of spermatogenic cells and disintegration of cellular associations in the seminiferous tubules of testes along with reduction in the diameter of cauda epididymal tubules and pseudostratification of their epithelial lining. Progeny (feeding on normal diet) of paternally treated rats has shown retarded growth.

Animals↗
PubMed2000

Otomycosis: a clinicomycologic study.

Otomycosis is a common fungal infection of the ear that is seen in the tropical and subtropical regions of the world. We performed mycologic analyses on debris and scraping samples from the external ear canals of 95 patients who had been clinically diagnosed with otomycosis. Seventy-one samples (74.7%) were positive for fungal growth; two of these samples contained two fungi, bringing the total number of isolates to 73. The most common pathogens were Aspergillus fumigatus (41.1% of all isolates), A niger (36.9%), and Candida albicans (8.2%).

Adult↗
PubMed1999

Myelination and behaviour of tenascin-C null transgenic mice.

The extracellular matrix glycoprotein tenascin-C is widely expressed during development and repair, making it surprising that few abnormalities have been found in transgenic mice lacking this molecule. We have therefore re-examined the transgenic mice described by Saga et al. [Saga, Y., Yagi, T., Ikawa, Y., Sakakura, T. & Aizawa, S. (1992) Genes Dev., 6 1821-1831] in which tenascin-C was knocked-out by homologous recombination, focusing on two aspects of the nervous system likely to reveal any abnormalities that might follow the loss of tenascin-C. First, we have determined the pattern of myelin and distribution of oligodendrocyte precursor cells in those areas, such as the optic nerve and retina where local concentrations of tenascin-C have been proposed to act as barriers to oligodendrocyte precursor migration and so prevent inappropriate myelination. Secondly, we have examined the behaviour of the mice in a number of well-characterized tests, e.g. beam-walking, passive avoidance and the Morris water maze. We find no abnormalities of myelination or oligodendrocyte precursor distribution in adult mice, showing that local concentrations of tenascin-C are not the sole mechanism responsible for the pattern of myelination in these regions of CNS. However, we do find a number of behavioural abnormalities in these mice and show that hyperlocomotion and deficits in coordination during beam walking can be ascribed to tenascin-C deficiency. The effects on coordination are, however, not seen on a 129 genetic background. Taken together, these results significantly extend the phenotype associated with tenascin-C deficiency but argue against a role in myelination.

Animals↗
PubMed1999

Effects of dietary selenium on biochemical composition of rat testis.

Treatment of rats with selenium (6 and 8 ppm in diet) for 6 and 9 weeks resulted in decrease in testicular protein, phospholipid content and LDH activity and an increase in the lipid, cholesterol content and activity of ACP and ALP. These alterations have been discussed in relation to interference of selenium in various metabolic processes of testis. It seems that selenium affects the oxido-reductase activity of glutathione and resulting in oxidative damage to testis.

Animals↗
PubMed1999

Screening for TORCH infections in pregnant women: a report from Delhi.

Primary TORCH infections (toxoplasmosis, rubella, cytomegalovirus and herpes simplex virus type 1 and 2) in the mother can lead to severe fetal anomalies or even fetal loss. A prospective study was designed to detect the seroprevalence of IgM antibodies to Toxoplasma gondii, rubella virus and cytomegalovirus and IgG antibodies to herpes simplex virus type 1 and 2. One hundred and twenty pregnant women presenting to the antenatal clinic of a tertiary health center were included in this study. Out of these 120 women 112 (93.4%) had evidence of one or more infections. Prevalence of IgG antibodies to HSV was 70%. Seropositivities for toxoplasmosis, rubella and CMV respectively were 11.6, 8.3 and 20.8%. Our data demonstrating high frequency of primary infections during pregnancy support the conclusion that routine prenatal TORCH screening is justified.

Adolescent↗
PubMed1998

Fates of endocytosed somatostatin sst2 receptors and associated agonists.

Somatostatin agonists are rapidly and efficiently internalized with the somatostatin sst2 receptor. The fate of internalized agonists and receptors is of critical importance because the rate of ligand recycling back to the cell surface can limit the amount of radioligand accumulated inside the cells, whereas receptor recycling might be of vital importance in providing the cell surface with dephosphorylated, resensitized receptors. Furthermore the accumulation of radioisotope-conjugated somatostatin agonists inside cancer cells resulting from receptor-mediated internalization has been used as a treatment for cancers that overexpress somatostatin receptors. In the present study, radio-iodinated agonists at the sst2 somatostatin receptor were employed to allow quantitative analysis of the fate of endocytosed agonist. After endocytosis, recycling back to the cell surface was the main pathway for both 125I-labelled somatostatin-14 (SRIF-14) and the more stable agonist 125I-labelled cyclo(N-Me-Ala-Tyr-d-Trp-Lys-Abu-Phe) (BIM-23027; Abu stands for aminobutyric acid), accounting for 75-85% of internalized ligand when re-endocytosis of radioligand was prevented. We have shown that there is a dynamic cycling of both somatostatin agonist ligands and receptors between the cell surface and internal compartments both during agonist treatment and after surface-bound agonist has been removed, unless steps are taken to prevent the re-activation of receptors by recycled agonist. Internalization leads to increased degradation of 125I-labelled SRIF-14 but not 125I-labelled BIM-23027. The concentration of recycled agonist accumulating in the extracellular medium was sufficient to re-activate the receptor, as measured both by the inhibition of forskolin-stimulated adenylate cyclase and the recovery of surface receptor number after internalization.

Animals↗
PubMed1998

Blockade of human P2X7 receptor function with a monoclonal antibody.

A monoclonal antibody (MoAb) specific for the human P2X7 receptor was generated in mice. As assessed by flow cytometry, the MoAb labeled human blood-derived macrophage cells natively expressing P2X7 receptors and cells transfected with human P2X7 but not other P2X receptor types. The MoAb was used to immunoprecipitate the human P2X7 receptor protein, and in immunohistochemical studies on human lymphoid tissue, P2X7 receptor labeling was observed within discrete areas of the marginal zone of human tonsil sections. The antibody also acted as a selective antagonist of human P2X7 receptors in several functional studies. Thus, whole cell currents, elicited by the brief application of 2',3'-(4-benzoyl)-benzoyl-ATP in cells expressing human P2X7, were reduced in amplitude by the presence of the MoAb. Furthermore, preincubation of human monocytic THP-1 cells with the MoAb antagonized the ability of P2X7 agonists to induce the release of interleukin-1beta.

Adenosine Triphosphate↗
PubMed1998

A minisatellite sequence within the propeptide region of the vacuolar carboxypeptidase Y gene of Schizosaccharomyces pombe.

We describe the presence of a minisatellite sequence that displays length polymorphisms in the fission yeast Schizosaccharomyces pombe. The minisatellite sequence was found to reside within the propeptide region of the vacuolar carboxypeptidase Y gene. The minisatellite sequence, which was found only at a single locus, was mitotically stable and displayed length polymorphisms between the two varieties of S. pombe (S. pombe var. pombe and S. pombe var. malidevorans). The minisatellite sequence, however, appeared to be species specific and was absent in other members of the Schizosaccharomyces genus. This report constitutes the first experimental demonstration of the presence of such sequences in yeasts.

Base Sequence↗
PubMed1997

PCR-mediated direct gene disruption in Schizosaccharomyces pombe.

We have examined the feasibility and efficiency of PCR-mediated direct gene disruptions in the fission yeast Schizosaccharomyces pombe. In the present study, the S.pombe ura4+ gene was amplified by PCR with oligonucleotides that had short flanking regions ( approximately 40 bp) to the target gene. Using this purified PCR product we were able to disrupt genes in an S. pombe strain bearing aura4 deletion, with an efficiency ranging between 1 and 3% among selected transformants. The results indicated that despite S.pombe's preference for non-homologous or illegitimate recombination, even very short stretches of homologous regions could be used to target genes at a defined frequency in this organism. The successful disruption of four independent genes (sts1+, gcs1+, gsh2+and hmt1+) by this method further demonstrates that, despite the relatively low efficiency, the method is very feasible, and it's simplicity, especially when coupled to phenotype-based screening, should greatly facilitate disruption of genes in S.pombe.

ATP-Binding Cassette Transporters↗
PubMed1997

Entomological and rodent surveillance in plague-suspected areas during September 1994 and thereafter.

Studies carried out in the states of Maharashtra, Gujarat, Uttar Pradesh and Union Territory of Delhi after the bubonic plague outbreak during 1994 revealed the presence of seven species of rodents, viz. Rattus rattus, R. norvegicus, Mus. musculus, Tatera indica, Suncus murinus, Bandicoota bengalensis and B. indica. The flea species encountered were Xenopsylla cheopis and X. astia. The X. cheopis and X. astia index recorded in different areas of Beed district of Maharashtra; Surat, Vadodra and Baruch districts in Gujarat and Varanasi district in Uttar Pradesh and their implications have been discussed. Insecticide suspectibility tests carried out against DDT, dieldrin, malathion and deltamethrin with X. cheopis collected from Maharashtra, Delhi and Varanasi revealed that this vector species is resistant to DDT and dieldrin but susceptible to malathion and deltamethrin. The prevalence and distribution of rodents species, high cheopis index and prevalence of Tatera indica just at the door steps of houses in village Mamla of Beed district provides highly congenital conditions for the intermingling of wild and domestic rodents and transfer of flea population from wild to domestic rodents and vice-versa. These conditions were found to be highly supportive for bubonic plague transmission in the district. The presence of Yersinia pestis antibodies in Rattus rattus collected from Beed, Surat and Varanasi areas are also indicative of bubonic plague in Beed and Varanasi and pneumonic plague in Surat during 1994.

Animals↗