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Biomedical subjects

A Khan

Publications and source records attributed to A Khan.

At least 343 records · Page 19Linked to original sources

Scarring following renal trauma in children.

OBJECTIVE: To assess factors relating to renal scarring following kidney injury. PATIENTS AND METHODS: A total of 25 children who had documented renal injury between 1981 and 1988 were included in the study and 19 were followed up for 1 month to 12 years (mean 5.5 years) and the development of hypertension and renal scars assessed using ultrasonography and radionuclide scans (dimercapto-succinic acid, DMSA). RESULTS: Of the 19 children 13 had renal contusions, four had renal lacerations and two sustained severe renal injury, one of whom had pelvi-ureteric disruption. Eighteen patients presented with macroscopic or microscopic haematuria except the patient with pelvi-ureteric junction disruption who presented 3 weeks later with abdominal distension, vomiting and hypertension. All the patients were managed without an operation except the latter patient who required nephrectomy. Renal scarring was demonstrated in four children at a mean follow-up of 3.5 years, one following renal contusion (5% scarring), two after renal laceration (50% scarring) and one after rupture of the kidney (100% scarring). In one patient intravenous pyelography did not reveal a renal scar but a radionuclide scan performed 5 years later demonstrated a scar. Transient hypertension was noted in only two patients but peripheral plasma renin levels were normal. CONCLUSION: Renal scars developed in four of 19 patients with renal trauma and more than half of the patients with severe renal injury. Long-term follow-up including a radionuclide scan is therefore necessary in patients with renal injury. Although no sustained hypertension was noted in any patients in this study, long-term blood pressure assessments would seem prudent.

Child↗

Evidence that increased glucose cycling in islets of diabetic ob/ob mice is a primary feature of the disease.

Glucose cycling (GC) is increased in pancreatic islets from hyperglycemic 6-mo-old ob/ob mice. We determined whether normalization of glycemia alters islet GC and insulin release in response to glucose as well as oxidation and utilization of the glucose. Mice were treated with phlorizin in dimethyl sulfoxide (DMSO) for 10 days, which resulted in normalization of blood glucose concentrations. Controls received DMSO. The mice were fasted overnight and killed, and their islets were isolated for measurements of insulin release at 5.5 and 16.7 mM glucose and at 16.7 mM glucose plus 10 mM arginine. GC was measured by the incorporation of 3H from 3H2O into carbon 2 of glucose, glucose oxidation by the yield of 14CO2 from [U-14C]glucose, and glucose utilization by the yield of 3H2O from [5-3H]glucose. Phlorizin treatment did not alter the response of insulin to glucose and to glucose plus arginine. GC was 30% in control and phlorizin-treated animals. Glucose oxidation and utilization were also the same in both groups. In fed 10- to 12-mo-old mice exhibiting a broad range of blood glucose levels, there was no correlation between GC and either insulin release or glucose concentrations. Thus the islets of ob/ob mice exhibit an increased rate of GC regardless of glycemia. This indicates that the increased rate of GC is an important characteristic of the diabetic syndrome in these animals and not simply secondary to hyperglycemia.

Animals↗

A study of nosocomial infection in relation to different host factors in an Indian teaching hospital.

Out of a total of 422 patients studied, 164 (38.8%) developed nosocomial infection. The rate was higher (41.6%) in males than in females (34.7%). A rising trend of infection was observed with age, maximum (69.6%) being in the above 60 age group. Nosocomial infection rate was inversely proportional to the socio-economic status of the patient. At the same time some underlying diseases in the patients influenced the rate of infection to a great extent, eg infection rates in patients with anaemia (53.7%), diabetes mellitus (85.2%), hypertension (82.0%) and obesity (51.5%) were much more than in patients with no such underlying disease (17.5%).

Adolescent↗

Rheumatic heart disease in India.

A cross-sectional study was carried out in rural areas of Jawan Block, District Aligarh, Uttar Pradesh, India, covering a total population of 3760 drawn from 11 villages. The total number of confirmed cases of rheumatic heart disease was 24 with a prevalence rate of 6.4 per 1000 of the general rural population. The prevalence of rheumatic heart disease increased with age until the age of 25 years. Females were more prone to rheumatic heart disease compared to males. Socio-economic class had a direct impact on the occurrence of rheumatic heart disease.

Adolescent↗

Glucose-6-phosphatase activity in islets from ob/ob and lean mice and the effect of dexamethasone.

In previous studies we demonstrated a much greater rate of glucose cycling (glucose-->glucose-6-P-->glucose) in islets from ob/ob mice than from lean litter mates. Cycling was further augmented by dexamethasone treatment. To determine whether these findings could be accounted for by increased islet glucose-6-phosphatase activity, we have now measured that enzyme's activity in permeabilized and sonicated islets and in islet microsomes. Activity in permeabilized islets from ob/ob mice was 19 times more than from lean litter mates (17.7 +/- 2.9 vs. 0.9 +/- 0.2 pmol/islet/min). Activity was 6 times higher when calculated per microgram of protein or microgram of DNA. Treatment of ob/ob mice with dexamethasone (25 micrograms/daily for 3 days) increased activity 2- to 3-fold. Activities were about twice as much in sonicated as permeabilized islets. There was no difference between glucose-6-phosphatase activity in microsomes prepared from islets of ob/ob and from lean mice, and the activity was relatively low. Thus, permeabilized islets can be used to determine glucose-6-phosphatase activity and study its regulation. The higher glucose cycling in islets of ob/ob mice and its stimulation by dexamethasone can be attributed to increased glucose-6-phosphatase activity.

Animals↗

Spinal epidural cavernous angioma presenting as a lumbar radiculopathy with analysis of magnetic resonance imaging characteristics: case report.

Epidural cavernous angiomas are apparently rare lesions. We present an unusual case of chronic lumbar radiculopathy secondary to an epidural cavernous hemangioma extending into the intervertebral foramen. Few such reports have had the benefit of modern neuroimaging techniques to aid in preoperative diagnosis, and, therefore, magnetic resonance imaging of these lesions has not been extensively described. This article discusses the implications of the clinical presentation of the patient and reviews the characteristic magnetic resonance imaging appearance of this lesion garnered from this case and from a review of the literature.

Adult↗

Effects of ECS on DNA single-strand breaks in rat brain cells.

We conducted a series of experiments to evaluate possible molecular mechanisms by which electroconvulsive therapy, a commonly used treatment for depression, may exert its adverse effects such as amnesia. We assessed the effects of repeated electroconvulsive shocks (ECS) alone and in combination with low-level radiograph irradiation on DNA single-strand breaks in cells in the rat brain, using a sensitive alkaline microgel electrophoresis assay method. Our results show that ECS, when administered alone, had no significant effects on DNA single-strand breaks in cells in either the hippocampus or the rest of the brain. However, repeated ECS when combined with a low-level radiograph irradiation produced a small but significant increase in DNA single-strand breaks in rat brain cells.

Animals↗

Organization and structure of an Onchocerca beta-tubulin gene.

In filarial worms, as in other eukaryotes, microtubules are essential multifunctional components. The major protein of microtubules is tubulin, a heterodimer of two distinct polypeptides, alpha and beta. Tubulin is particularly important in helminthic parasites as a target for anthelminthic benzimidazoles, which bind to it and inhibit microtubule assembly. Two genomic Onchocerca gibsoni libraries were constructed in lambda NM1149 (EcoRI and HindIII). Three clones accounted for the entire gene: one from the EcoRI library (using a Plasmodium falciparum probe) containing the central part of the gene, and two from the HindIII library (using as probes PCR amplified fragments from the ends of the EcoRI clone) which, respectively, contained the 5'- and 3'-ends of the gene. The sequencing procedure for the EcoRI clone relied on the construction of a double-digested DraI/HindIII shotgun library. A number of recombinants were sequenced and aligned with each other for comparison. The sequencing of the overlapping 5'- and 3'-end clones was done by using a series of oligonucleotides. The sequence of the O. gibsoni beta-tubulin gene was completely determined, revealing an exceptionally complex structure as compared to the known beta-tubulin genes: 5,797 base pairs containing 12 exons and 11 introns. The deduced polypeptide is 444 amino acids long, and its sequence is highly conserved. The position of some introns appear to demarcate functional domains within the protein.

Amino Acid Sequence↗

Venlafaxine in depressed geriatric outpatients: an open-label clinical study.

A 12-month open-label clinical trial was conducted to evaluate patient acceptance and safety of venlafaxine, a novel antidepressant, in ambulatory geriatric depressed patients. The sample consisted of 58 depressed patients aged 65 years and older who needed long-term antidepressant treatment. The setting was multiple study sites in California, Florida, New York, Utah, and Washington. All patients took venlafaxine; 52 qualified for the intent-to-treat analysis, and 24 completed 12 months of treatment. Repeated-measures analysis of variance within subjects showed significant improvements in Clinical Global Impressions severity and improvement, Modified Symptom Checklist, and Quality of Life Questionnaire scores. One patient developed a rash that was judged to be a serious drug-related side effect. The most common side effects were headache (n = 25), nausea (n = 21), insomnia (n = 18), dry mouth (n = 18), and sweating (n = 18). The results demonstrate the safety and patient acceptance of venlafaxine in depressed geriatric outpatients for acute and maintenance treatment.

Aged↗

Particle activity and in vivo pulmonary response to freshly milled and aged alpha-quartz.

This study examined the possibility of freshly fractured alpha-quartz being more toxic and inflammatory in vivo than aged quartz of the same composition and particle size. Fresh quartz was generated by a jet mill, and used immediately, while aged dust was stored for two months before use. Both the production of hydrogen peroxide and hydroxyl radicals and the analysis of surface radicals verified the enhanced surface activity of fresh quartz. Male Fischer 344 rats were exposed to fresh or aged alpha-quartz by inhalation (20 mg center dot m-3, 5 h per day, 5 d per week, for 2 weeks) and their pulmonary responses were determined 1--3 d postexposure. Exposure to aged quartz resulted in an increase in cytotoxic and inflammatory parameters. In comparison, the inhalation of freshly cleaved quartz resulted in dramatically greater increases in all of the pulmonary responses. This finding suggests that exposure to freshly machined quartz may result in a greater risk of pulmonary disease.

Administration, Inhalation↗

Role of intrathymic clonal deletion and peripheral anergy in transplantation tolerance induced by bone marrow transplantation in mice conditioned with a nonmyeloablative regimen.

We have investigated the mechanism of tolerance induced by allogeneic bone marrow transplantation (BMT) in mice conditioned with a nonmyeloablative regimen. Permanent mixed chimerism and skin allograft tolerance were achieved when recipient B10 (H-2b) mice were pre-treated with anti-CD4 and anti-CD8 mAbs, thymic irradiation, and 3 Gy whole body irradiation, followed by injection of B10.A (H-2a) bone marrow cells. V beta 11+ T cells are normally deleted in I-E+ B10.A mice, but not in I-E- B10 mice. In spleens of mixed B10.A-->B10 chimeras, V beta 11+ B10 T cells were reduced but detectable in the first 6 wk after BMT, and later became undetectable. Splenic V beta 11+ T cells were unresponsive to receptor cross-linking with V beta 11-specific mAb, demonstrating anergy. B10 V beta 11+ T cells were also detected in spleens of mice that were thymectomized before BMT. In PBL of chimeras, V beta 11+ T cells were undetectable for at least 1.5 yr. Thymocyte chimerism and extensive clonal deletion of mature V beta 11+ B10 thymocytes were observed as early as 10 days post-BMT and at all subsequent time points in thymi of mixed chimeras. Rare I-E+ donor cells were detected in day 10 thymi, and these increased progressively in frequency at later times. In chimeras prepared in the reciprocal strain combination, B10-->B10.A, B10 donor V beta 11+ T cells were undetectable in PBL. Together, our results implicate both central clonal deletion and peripheral clonal anergy in tolerance induced with our regimen. A very low number of intrathymic donor cells or low density of Ag expression is sufficient to mediate extensive clonal deletion of thymocytes that recognize donor Ags.

Animals↗

Localization of amplified MYC gene sequences to double minute chromosomes in acute myelogenous leukemia.

Cytogenetic and molecular studies were performed on two dmin-bearing acute myelogenous leukemia (FAB-M2) samples. Both cases were characterized by complex karyotypes containing interstitial deletions of the long arm of chromosome 8 altering band 8q24.1, aberrations affecting the short arm of chromosome 17, and multiple double minute chromosomes (dmin). Using a 1.4 kb cDNA probe coding for the third exon of the MYC oncogene, DNA slot blots indicated MYC gene sequences were amplified in both samples. Fluorescence in situ hybridization using a 9.0 kb genomic probe for MYC was performed in one case and localized the amplified MYC gene sequences to the dmin. Neither patient achieved a complete remission using traditional induction chemotherapy. The complex karyology with amplification of MYC gene sequences appears to represent a poor prognostic subgroup of acute myelogenous leukemia.

Aged↗

The imidazoline derivative calmidazolium inhibits voltage-gated Ca(2+)-channels and insulin release but has no effect on the phospholipase C system in insulin producing RINm5F-cells.

The present study shows that the calmodulin antagonist calmidazolium inhibited influx of Ca2+ through voltage-gated Ca(2+)-channels in clonal insulin producing RINm5F-cells. The mechanism of inhibition may involve both Ca(2+)-calmodulin-dependent protein kinases and direct binding of calmidazolium to the Ca(2+)-channel. Calmidazolium did not affect uptake of Ca2+ into intracellular Ca(2+)-pools, inositol 1,4,5-trisphosphate (InsP3) formation or action on intracellular Ca(2+)-pools. The calmodulin inhibitor also did not affect glucose utilization or oxidation in RINm5F-cells, speaking against an unspecific toxic effect of the compound. KCl-and ATP-stimulated insulin release from RINm5F-cells was attenuated by calmidazolium, whereas basal hormone secretion was unaffected.

Animals↗

NS-3, a TRH analog, reverses repeated ECS-induced deficits in water maze performance in the rat.

Rats given five consecutive daily electroconvulsive shock (ECS) treatments and trained to run in the Morris water maze, starting three days posttreatment, showed deficits in learning and memory functions. Treatment before each training session with the thyrotropin-releasing hormone (TRH) analog NS-3 [(CG-3703), (3R),(6R)-6-methyl-5-oxo-3-thiomorphorinyl-l-histidyl-l-prolinamid e tetrahydrate] reversed these behavioral deficits. The possible use of TRH and its analogs as therapeutic treatment for the cognitive dysfunctions resulting from electroconvulsive shock treatment for depression and the possible involvement of central cholinergic systems in the cognitive dysfunctions are discussed.

Animals↗

Obesity among young Saudi female adults: a prevalence study on medical and nursing students.

The prevalence of obesity was examined among Saudi female medical and nursing students. The analysis was made on 222 students whose ages ranged from 18-25 years. Standard procedures for measuring weight, height and triceps skinfold measurements were conducted. The criteria for obesity used in the present study were: (i) body mass index (W/H2) in kg/m2 > or = 25 and (ii) triceps skinfold measurement of > or = 25 mm (> or = 85th percentile for ages 18-24 years). The prevalence rate of obesity by body mass index was found to be 30.6% with more girls falling in the Grade I (26.1%) than the Grade II (4.5%) category. Using the skinfold measurement as a standard, a smaller proportion (16.8%) of students was observed to be obese indicating variation in the sensitivity of the two indices as measures of body fatness. Irrespective of the method used for estimation, the prevalence of obesity in these young Saudi women was notably high and supports findings of earlier studies for a common occurrence of female obesity in this region. Preventive programmes for weight control and a healthy lifestyle among Saudi females should be emphasised from young adulthood or perhaps earlier.

Adolescent↗