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Biomedical subjects

M S Kumar

Publications and source records attributed to M S Kumar.

At least 37 records · Page 2Linked to original sources
PubMed1993

Chronic vaginal prolapse during pregnancy in a bitch.

A 4-year-old bitch was referred with chronic vaginal prolapse. It was first noticed during estrus, about 58 days prior to referral. Artificial insemination (AI) was performed twice after reducing the prolapse manually. Abdominal radiography (53 to 55 days after AI) was performed by the attending veterinarian and the bitch was determined to be not pregnant. Serum progesterone and estradiol concentrations were 1.38 ng/ml and 1.79 pg/ml, respectively. With the bitch under general anesthesia, the vaginal prolapse was partially reduced and a hysteropexy was performed. Six days after surgery, the bitch delivered a live male pup. It is recommended that bitches so affected should not be bred, and that those not required for breeding should be ovariectomized.

Animals↗
PubMed1993

Distribution of catecholamines in the central nervous system of the pig.

The objective of this study was to document, through comprehensive means, normal distribution and concentration of catecholamines in various regions of the CNS of pigs, an increasingly popular animal model used for transgenic manipulation of neural genes. The effects of gonadal steroidal status on this distribution were also assessed by comparing CNS catecholamine concentrations among mature male pigs (boars), immature (gilts) and mature female pigs (sows), and adult male pigs castrated prepuberally (barrows). Dissected tissue samples from the CNS were extracted in 2 N acetic acid, filtered through a 0.2 micron filter, then quantitated by reverse-phase high performance liquid chromatography using a C-18 reverse phase column with electrochemical detection. In both boars and sows the highest concentrations of norepinephrine (NE) were found in the diencephalic areas and brain stem. Gilts exhibited elevated concentrations of NE in the olfactory bulbs (OB), hypothalamus, pons, and corpus trapezoideum-locus ceruleus (LC) compared to lower concentrations in corresponding areas of sows. Prepuberal castration of the male was associated with significantly lower NE concentrations in the striatum, periaqueductal area (PAG), pons, LC, and spinal cord. The sow exhibited significantly lower NE concentrations in the mammillary area (Mam), PAG, pons, and spinal cord than those in corresponding areas of the boar. Dopamine concentrations appeared to be similar in all areas of the brain and spinal cord studied in the sow and boar. Results demonstrated that prepuberal castration of the male appears to significantly alter the DA content of the Mam and dorsal spinal cord, in contrast to gilts who possess significantly higher concentrations of DA. It is concluded from our studies that in general, catecholamine concentrations in various regions of the brain and spinal cord of sexually mature pigs parallel distributions of neuropeptides, substance P, and methionine enkephalin, as previously reported. In addition, significant association was found between gonadal activity and catecholamine concentrations in discrete areas of the pig brain.

Animals↗
PubMed1993

Effect of midazolam infusion and flumazenil administration on epinephrine arrhythmogenicity in dogs anesthetized with halothane.

BACKGROUND: Midazolam is being selected increasingly for use in patients with cardiovascular compromise. Although clinical doses of midazolam have minimal effects on cardiac function, the influence of midazolam (and other benzodiazepine sedatives) on cardiac arrhythmogenesis has yet to be elucidated fully. METHODS: In this study, we investigated the effect of midazolam, with and without flumazenil, on the arrhythmogenic serum concentration of epinephrine (ACE) in six halothane-anesthetized dogs. Midazolam was administered as a loading dose (1.5 mg/kg over 5 min) followed by a 4.5-h infusion at two rates (10 and 40 micrograms.kg-1 x min-1) to achieve and maintain predetermined clinical and supraclinical plasma midazolam concentrations. The arrhythmogenic serum concentration of epinephrine determinations were made prior to midazolam infusion, following 2 h of midazolam infusion and following 3.5 h of midazolam infusion and 1 mg flumazenil/kg i.v. Saline control studies were also performed in four of the six dogs. RESULTS: Plasma midazolam concentrations ranged from 363 to 855 ng/ml in the low-dose infusion study, essentially spanning the clinically effective range for humans. In the high-dose infusion study, plasma midazolam concentrations were up to four times greater, ranging from 1168 to 3563 ng/ml. The arrhythmogenic serum concentration of epinephrine values were unchanged following low-dose midazolam infusion and saline. In the high-dose study, ACE increased from baseline values of 68 +/- 13 (SEM) ng/ml to 112 +/- 25 ng/ml (P = .03) following midazolam infusion and decreased to 79 +/- 13 ng/ml with flumazenil administration. Plasma midazolam concentrations, however, were poorly correlated with ACE values normalized for control ACE (ACE ratio). Diastolic arterial pressure was significantly depressed following both low-dose (-14%) and high-dose (-19%) midazolam infusion. This decrease in blood pressure was unaffected by flumazenil administration. Other hemodynamic parameters were unaffected by drug treatment. CONCLUSIONS: This study has demonstrated that midazolam infusion results in either no effect (with clinical plasma midazolam concentrations) or flumazenil-reversible suppression (with supraclinical concentrations) of halothane-epinephrine arrhythmogenesis.

Anesthesia, Inhalation↗
PubMed1993

Ultrasound-guided needle aspiration of amoebic liver abscess.

This prospective study was carried out on 200 patients with clinically, ultrasonographically and serologically confirmed amoebic liver abscess. The role of ultrasound-guided needle aspiration in addition to medications was evaluated compared to drug treatment alone. Both the groups were monitored clinically and sonographically for up to 6 months after diagnosis. The initial response (after 15 days) was better in the aspirated group (P < 0.05) but resolution of abscess after 6 months were similar. There was a more rapid clinical response in the aspirated group, particularly in those with larger (> 6 cm) abscesses and there were no complications. Percutaneous ultrasound-guided needle aspiration is a safe diagnostic and therapeutic approach which enhances clinical recovery, accelerates resolution, especially in large abscesses, and prevents complications.

Biopsy, Needle↗
PubMed1992

Exclusive asymptomatic neonatal infections by human rotavirus strains having subgroup I specificity and "long" RNA electropherotype.

A large number of stool specimens, of healthy newborn infants, collected from various hospitals and clinics in Bangalore City, India, have been examined for the presence of asymptomatic rotaviral excretion. Out of 370 samples analysed during a three year period from 1988 to 1991, 133 specimens (36%) were positive for rotavirus RNA. All these asymptomatic neonatal strains, without exception, showed "long" RNA pattern, but subgroup I specificity. Serotype analysis by ELISA or by hybridization with serotype-specific probes indicated that these strains probably represent a new serotype in newborn children. We find an exclusive association of human rotaviruses having "long" RNA pattern and subgroup I specificity with asymptomatic neonatal infections in contrast to the earlier observations of association of such unusual strains with acute gastroenteritis in young children.

Antigens, Viral↗
PubMed1992

Interleukin-1-induced corticosterone release occurs by an adrenergic mechanism from rat adrenal gland.

Interleukin-1 (IL-1) has been shown to stimulate corticosterone release from the adrenal gland directly, and indirectly through activation of the hypothalamic-pituitary-adrenal axis. The aim of this paper was to determine whether IL-1-stimulated corticosterone release occurs indirectly through the local release of catecholamines from the rat adrenal gland. To accomplish this, experiments were conducted on both quartered rat adrenal glands and primary cultures of dispersed adrenal cells. Incubation of quartered adrenals with adrenocorticotropic hormone (ACTH, 10(-12) to 10(-8) M) or IL-1 beta (10(-12) to 10(-8) M) resulted in dose-dependent increases (P less than 0.05) in corticosterone release. Corticosterone release stimulated by 10(-8) M doses of ACTH and IL-1 beta began to rise 30 min after incubation and peaked at 2 h. In primary cultures of adrenal cells, IL-1 alpha and IL-1 beta elevated corticosterone release after a 24-h incubation period. ACTH elevated corticosterone levels at 4 and 24 h. The stimulatory effect of IL-1 on corticosterone release was mimicked by epinephrine (10(-6) M), and was selectively blocked by the alpha-adrenergic antagonist phentolamine (10(-5) M). The beta-adrenergic antagonist propranolol (10(-5) M) did not change IL-1-induced corticosterone release. Neither phentolamine nor propranolol had an effect on ACTH-stimulated corticosterone release. Both IL-1 alpha and IL-1 beta significantly increased (P less than 0.05) epinephrine levels after a 24-h incubation period compared with media-treated controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗