Search PubMed⌕ Search

Biomedical subjects

A Kumar

Publications and source records attributed to A Kumar.

At least 1,333 records · Page 74Linked to original sources
PubMed1992

Postnatal laminar development of cholinergic receptors, protein kinase C and dihydropyridine-sensitive calcium antagonist binding in rat visual cortex. Effect of visual deprivation.

The postnatal ontogeny of 3H-pirenzepine and 3H-oxotremorine-M binding to M1-and M2-muscarinic acetylcholine receptors, respectively, as well as 3H-nicotine binding to neuronal nicotinic acetylcholine receptors, 3H-phorbol-12,13-dibutyrate binding to protein kinase C and 3H-PN200-110 binding to dihydropyridine-sensitive calcium channels was studied in individual layers of the visual cortex in both normally raised and monocularly deprived rats (one eyelid sutured at the age of 11 days) using quantitative receptor autoradiography. Postnatal ontogeny of M1-muscarinic receptors is similar in each visual cortical layer reaching the highest receptor density at the age of 15 days, whereas M2-muscarinic binding sites increase gradually from day 7 up to day 34. Highest 3H-nicotine binding is reached in all visual cortical layers at postnatal day 15 followed by a considerable decrease in binding sites until day 25. Phorbol ester binding rises considerably from birth until the age of 15 days reaching nearly the adult value in the upper layers, whereas in layers V and VI a marked decrease in binding levels until adulthood can be observed. The developmental course of 3H-PN200-110 binding sites is similar in all visual cortical layers and exhibits a moderate rise in binding sites between postnatal days 7 and 15. Monocular deprivation results in permanent changes in the developmental profiles of phorbol ester as well as calcium antagonist binding sites, whereas the alterations in muscarinic and nicotinic cholinergic receptors following monocular deprivation are only of transient nature. The data presented suggest that acetylcholine plays a modulatory role during a certain period of early postnatal maturation of the visual cortex by affecting both cholinergic receptors and associated second messenger cascades.

Age Factors↗
PubMed1992

In vitro fertilization in the natural cycle.

In vitro fertilization in the natural or spontaneous reproductive cycle was first described by Edwards and his colleagues in 1980 following the birth of their first natural cycle IVF baby 2 years earlier. Many groups attempted to follow their lead but it was almost ten years later that the next publication of success appeared (Foulot et al, 1989). The concept of IVF in the natural cycle is particularly attractive and so in 1987 our group also started evaluating the technique. Initial success in the patients with tubal lesions was not translated to patients with other infertility indications. Unfortunately the technique as initially developed was relatively inefficient with significant procedural losses at each stage. Over the succeeding four years a number of changes have been introduced and the efficiency considerably improved. Although these changes have improved take-home baby rates, overall pregnancy rates per embryo have not altered and are still lower than spontaneous in vivo pregnancy rates. It is likely that in the future, with current developments in culture techniques and greater understanding of gamete biology, this situation will change significantly.

Female↗
PubMed1992

Post-antibiotic effect of ceftazidime, ciprofloxacin, imipenem, piperacillin and tobramycin for Pseudomonas cepacia.

The post-antibiotic effects (PAE) of ceftazidime, ciprofloxacin, imipenem, piperacillin and tobramycin were studied for ten strains of Pseudomonas cepacia isolated from patients with cystic fibrosis. Antibiotic concentrations used for exposure were either the MIC of each agent for the sensitive isolates or the recommended sensitivity breakpoint concentrations for the resistant isolates. After 2 h of exposure, cultures were rapidly diluted 1000-fold to eliminate the antibiotic. Out of the ten isolates, there were eight sensitive to ceftazidime, six to ciprofloxacin, six to imipenem, nine to piperacillin and five to tobramycin. All antibiotics tested demonstrated PAE for some isolates of P. cepacia, however, each antibiotic failed to produce a PAE for at least one isolate. The mean PAE was 1.35 h for ceftazidime, 2.38 h for ciprofloxacin, 2.39 h for imipenem, 2.16 h for piperacillin and 1.77 h for tobramycin. Imipenem demonstrated PAE of > or = 0.5 h for all sensitive isolates tested; ceftazidime, piperacillin, ciprofloxacin and tobramycin demonstrated PAE of > or = 0.5 h for 6/8, 8/9, 5/6 and 2/5 sensitive isolates, respectively. These data indicate that several antibiotics have significant (> or = 0.5 h) PAE for isolates of P. cepacia.

Burkholderia cepacia↗
PubMed1992

Adult-onset Still's disease in India.

Adult onset Still's disease was provisionally diagnosed in 31 patients from northern India over a period of five years, in 27 of whom the diagnosis was subsequently felt to have been confirmed. This report describes the clinical characteristics of these patients along with the different therapeutic measures used and their response. Adult onset Still's disease should be considered in the differential diagnosis of 'pyrexia of unknown origin'.

Adolescent↗
PubMed1992

Atropine and naloxone sensitive stimulation produced analgesia from pretectal nucleus in rat.

Mild and brief electrical stimulation of sites in the pretectal nucleus (PTN) of rats evoked potent analgesia of long duration, without significant aversions and was unassociated with motor deficit. The present study has analysed effects of opioidergic and cholinergic neurotransmitter antagonists administered intracerebroventricularly (i.c.v.) on this analgesia. Pretreatment either with naloxone or atropine sulphate both in doses of 30 and 50 micrograms each, respectively i.c.v., 10 min prior to subsequent pretectal stimulation, significantly attenuated the increase in tailflick latency. The antagonism of pretectal stimulation produced analgesia (PSPA) by naloxone and atropine, raises the possibility of involvement of both endogenous opioids and cholinergic mechanisms in pretectal analgesia.

Analgesia↗
PubMed1992

Intravenous midazolam for the treatment of refractory status epilepticus.

OBJECTIVE: To determine the usefulness of midazolam as a therapeutic agent for status epilepticus refractory to conventional treatment. DESIGN: Retrospective study. SETTING: ICUs of two university hospitals. PATIENTS: Seven patients with refractory status epilepticus who failed treatment with diazepam, lorazepam, and phenytoin, with or without phenobarbital. All patients received mechanical ventilation before receiving midazolam. INTERVENTIONS: Intravenous midazolam by bolus administration followed by infusion. MEASUREMENTS AND MAIN RESULTS: Midazolam terminated status epilepticus in all patients in less than 100 secs, as determined by clinical observation (three patients) or electroencephalographic monitoring (four patients). One patient developed mild hypotension. CONCLUSIONS: In this small study, midazolam appears to be an effective and safe alternative to high-dose barbiturate coma for the termination of status epilepticus when conventional agents have failed.

Adult↗
PubMed1992

Septic arthritis due to Pasteurella multocida.

We have reported two cases of septic arthritis caused by Pasteurella multocida, the first, septic polyarthritis unrelated to animal contact and the other, septic monarthritis after a cat scratch. Serious infections with this gram-negative bacillus must be treated with intravenous penicillin, ampicillin, or a third-generation cephalosporin; aminoglycosides are not effective. A high index of suspicion is appropriate when there is a history of a recent animal-inflicted wound, though infection may also occur with either nontraumatic animal contact or no recognized animal contact at all.

Adult↗
PubMed1992

Differential Expression and Sequence Analysis of Ribosomal Protein Genes Induced in Stolon Tips of Potato (Solanum tuberosum L.) during the Early Stages of Tuberization.

cDNA clones of two genes, TUBS19 and TUBL7, which show a 15- to 20-fold increase in transcript level in the stolon tip during the early stages of tuberization, have been isolated by differential screening. These genes are also expressed in leaves, stems, and roots, and the expression pattern in these organs changes on tuberization. Southern analysis shows that there are similar sequences in the genome of nontuberizing wild-type potato species Solanum brevidens and in Lycopersicon esculentum (tomato). Sequence analysis reveals a high degree of similarity between the TUBS19 cDNA and the eukaryotic S19 ribosomal protein gene. TUBL7 cDNA shows similarity to another eukaryotic ribosomal protein gene, L7.

Journal Article↗
PubMed1992

The effect of music on ketamine induced emergence phenomena.

The purpose of this investigation was to assess the influence of music on emergence phenomena after ketamine anaesthesia. Fifty ASA 1 patients undergoing minor gynaecological procedures were randomly divided into two equal groups. Patients in the treated group were played music of their choice through headphones from 5 min before induction of anaesthesia to 15 min postoperatively. Although the incidence of emergence phenomena was similar in both groups the effects tended to be more pleasant and acceptable in those to whom music was played. The majority of patients in the study group (80%) expressed their willingness to have a similar anaesthetic in the future compared to 52% in the control group (p less than 0.05).

Adult↗
PubMed1992

Monoclonal antibodies bind identically to both spores and hyphae of Aspergillus fumigatus.

Immunoelectron microscopy (IEM) was used to determine the binding of six monoclonal antibodies (MoAbs) produced against Aspergillus fumigatus antigens present on or within the conidia and hyphae of the fungus. Antigen-antibody complexes were demonstrated in EM using labelled colloidal gold particles (15 nm). Three out of 6 MoAbs (C9, F12 and H10) reacted only with the cytoplasmic components of A. fumigatus while the remaining three (B12, F6G5 and D6E6) showed reactivity to both cytoplasm and cell wall of the conidia and hyphae. The results indicate that IEM is of considerable value in determining and selecting monoclonal antibodies having specific reactivity with diverse antigenic components.

Antibodies, Fungal↗
PubMed1992

Oral clonidine premedication for elderly patients undergoing intraocular surgery.

In a randomized double-blind study, the effects of clonidine premedication as a sedative, anxiolytic, analgesic and oculohypotensive agent were studied in 100 elderly patients (62 to 65 +/- 10 years, ASA grade I-II) undergoing elective intraocular surgery under local anaesthesia. The control group (Group A, n = 50) received oral diazepam 0.15 mg/kg 120 min before surgery and Group B (n = 50) received oral clonidine 300 micrograms 120 min before surgery. Two hours after the premedication, there was significantly more sedation (P less than 0.05) and less subjective anxiety (P less than 0.05) in the clonidine group than in the control group. There was a significant fall in intraocular pressure (IOP) from 20 +/- 0.5 to 13 +/- 0.5 mmHg (P less than 0.05) and significant reduction in systolic and diastolic blood pressure (BP) and heart rate (HR) (P less than 0.05) in the clonidine group as compared to the control group. Perioperatively, significantly more supplementation with i.v. diazepam was given in the control group than in the clonidine group (P less than 0.01). The incidence of intra-operative hypertension (P less than 0.01) and tachycardia (P less than 0.05) was significantly greater in the control group than in the clonidine group. A significantly larger number of patients in the clonidine group scored a Post-Anaesthesia Recovery (PAR) score of 10 as compared to the control group (P less than 0.01). There was no statistical difference in the postoperative Visual Analogue Scale (VAS) scores for pain, number of analgesic requests and emesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1992

Routine radio-imaging in filarial chyluria--is it necessary in developing countries?

Chyluria is a common presentation of filariasis in developing countries and mostly affects economically poor classes. The judicious use of investigations is mandatory to keep the cost of treatment acceptable. A modified plan is suggested for managing such patients without using retrograde pyelography or lymphangiography. A total of 54 patients were studied at 2 separate institutions, with retrograde pyelography being carried out at one institution but not at the other. All patients were treated primarily by the instillation of 1% silver nitrate, with an initial success rate of 70%. Eight patients who failed to respond underwent pyelolymphatic disconnection, the success rate being 88%. The omission of retrograde pyelography and lymphangiography had no effect on either treatment or outcome. The value of these radio-imaging techniques is discussed.

Adult↗
PubMed1992

Management of impacted upper ureteric calculi: results of lithotripsy and percutaneous litholapaxy.

Despite the availability of lithotripsy and endourology, clear guidelines on the management of impacted upper ureteric calculi are lacking. In this study, 51 upper ureteric calculi treated with in situ extracorporeal shock wave lithotripsy (ESWL) were classified according to the degree of impaction as indicated by proximal back pressure changes. Patients with mild proximal hydronephrosis (or none at all) had a success rate of 93% but only 35% of those in the impacted group (moderate to severe hydronephrosis) had a successful outcome. A percutaneous antegrade approach to 29 impacted upper ureteric calculi resulted in total clearance in 23 cases; 4 other patients were rendered stone-free following additional procedures, an overall success rate of 93%. The only complication was a ureteric stricture in 1 patient. We recommend the percutaneous approach in the management of impacted upper ureteric calculi.

Humans↗
PubMed1992

Differential effect of ultraviolet-B radiation on certain metabolic processes in a chromatically adapting Nostoc.

The impact of UV-B radiation on growth, pigmentation and certain physiological processes has been studied in a N2-fixing chromatically adapting cyanobacterium, Nostoc spongiaeforme. A brownish form (phycoerythrin rich) was found to be more tolerant to UV-B than the blue-green (phycocyanin rich) form of N. spongiaeforme. Continuous exposure to UV-B (5.5 W m-2) for 90 min caused complete killing of the blue-green strain whereas the brown strain showed complete loss of survival after 180 min. Pigment content was more strongly inhibited in the blue-green strain than in the brown. Nitrogenase activity was completely abolished in both strains within 35 min of UV-B treatment. Restoration of nitrogenase occurred upon transfer to fluorescent or incandescent light after a lag of 5-6 h, suggesting fresh synthesis of nitrogenase. Unlike the above processes, in vivo nitrate reductase activity was stimulated by UV-B treatment, the degree of enhancement being significantly higher in the blue-green strain. Like the effect of UV-B on nitrogenase, 14CO2 uptake was also completely abolished by UV-B treatment in both strains. Our findings suggest that UV-B may produce a deleterious effect on several metabolic activities of cyanobacteria, especially in cells lacking phycoerythrin. Strains containing phycoerythrin appear to be more tolerant to UV-B, probably because of their inherent property of adapting to a variety of light qualities.

Adaptation, Physiological↗
PubMed1992

Bilateral branch vein occlusion.

Bilateral branch retinal vein occlusion is a relatively rare occurrence. We report 4 patients who presented with bilateral branch retinal vein occlusion and in each of these cases the fellow eyes were involved within 6 months of the initial episode. The patients were relatively young and all of them had associated essential hypertension. The patients maintained a relatively good visual acuity through a 6-months to 1-year follow-up. This report highlights this rare entity, the associated risk factors and visual prognosis.

Adult↗
PubMed1992

Aspergillus antigen-induced eosinophil differentiation in a murine model.

Eosinophilia is a prominent feature of the cellular response in allergic and parasitic diseases. Allergic bronchopulmonary aspergillosis due to colonization of the lungs of some asthmatics with Aspergillus fumigatus is characterized by high levels of serum immunoglobulin E and peripheral blood (PB) and lung eosinophilia. This study investigates the role of eosinophils in the pathogenesis of allergic bronchopulmonary aspergillosis by using a mouse model. BALB/c mice were immunized intranasally and intraperitoneally with A. fumigatus antigens (Ag), and the eosinophils in PB and bone marrow (BM) were enumerated. Eosinophilopoiesis in BM cultures was studied in the presence of murine recombinant interleukin-5 (mrIL-5) and supernatants from pokeweed mitogen-stimulated spleen cells as the source of eosinophil differentiation factors. Eosinophils were quantitated by direct counting and by estimating eosinophil peroxidase activity. The results indicate that the percentage of eosinophils in the PB (5.77 +/- 1.17) and the BM (11.19 +/- 4.31) of mice exposed to A. fumigatus Ag was higher than in controls (PB, 2.42 +/- 0.76; BM, 5.12 +/- 2.79; P less than 0.01 for both). Similarly, a significant increase in eosinophils was observed in the BM population from mice exposed to A. fumigatus Ag compared with that in controls when cultured with murine recombinant interleukin-5 (23.13 +/- 7.14 versus 13.77 +/- 5.79, P less than 0.01), indicating that the mice exposed to A. fumigatus Ag had significantly greater numbers of eosinophil precursors in their BM. This study demonstrates that A. fumigatus Ag may be involved in the in vivo commitment of stem cells in the eosinophil differentiation pathway.

Animals↗