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Biomedical subjects

K V Kumar

Publications and source records attributed to K V Kumar.

At least 19 recordsLinked to original sources
PubMed2005

Protective effect of CardiPro against doxorubicin-induced cardiotoxicity in mice.

The effect of CardiPro, a polyherbal formulation, with an antioxidant property, has been studied on doxorubicin (DXR)-induced cardiotoxicity in mice. CardiPro (150 mg/kg b.w., twice daily was administered orally for 7 weeks along with four equal injections (each containing 4.0 mg/kg b.w., DXR) intraperitoneally, once weekly (cumulative dose 16 mg/kg). After a 3-week post DXR treatment period, cardiotoxicity was assessed by noting mortality, volume of ascites, liver congestion, changes in heart weight, myocardial lipid peroxidation, antioxidant enzymes and histology of heart. DXR-treated animals showed higher mortality (50%) and more ascites. Myocardial SOD and glutathione peroxidase activity were decreased and lipid peroxidation was increased. Histology of heart of DXR-treated animals showed loss of myofibrils and focal cytoplasmic vacuolization. CardiPro significantly protected the mice from DXR-induced cardiotoxic effects as evidenced by lower mortality (25%), less ascites, myocardial lipid peroxidation, normalization of antioxidant enzymes and minimal damage to the heart histologically. Our data confirm the earlier reports that DXR cardiotoxicity is associated with the free radical-induced tissue damage. Administration of CardiPro, with an antioxidant property, protected the DXR-induced cardiotoxicity in mice.

Animals↗
PubMed2001

Anaesthetic and intensive care aspects of spinal injury.

Over the last few years, spinal injuries have been classified depending upon their causative mechanism and on the basis of three column concept of the structure of vertebral column. The concept of primary and secondary injury has laid more stress on prevention and treatment of secondary injury. Methyl prednisolone still remains the drug of choice for prevention of secondary injury. Spinal injury involves all organ systems of the body depending on the level of lesion. Immobilisation of injured spine and maintenance of adequate airway after spinal injury need immediate attention. Orotracheal intubation under general anaesthesia, with manual in-line traction, is still considered the best method. Hypotension, hypertension and hyperglycaemia should be avoided during anaesthesia. Care should be taken to avoid effects of autonomic hyper reflexia. Spinal cord functions should be monitored and, if required, induced hypotension can be used with adequate monitoring.

Anesthesia↗
PubMed2000

Carvedilol: a beta blocker with antioxidant property protects against gentamicin-induced nephrotoxicity in rats.

Gentamicin is an antibiotic effective against gram negative infections, whose clinical use is limited by its nephrotoxicity. Since the pathogenesis of gentamicin-induced nephrotoxicity involves oxygen free radicals, the antioxidant carvedilol may protect against gentamicin-induced renal toxicity. We therefore tested this hypothesis using a rat model of gentamicin nephrotoxicity. Carvedilol (2 mg/kg) was administered intraperitoneally 3 days before and 8 days concurrently with gentamicin (80 mg/kg BW). Estimations of urine creatinine, glucose, blood urea, serum creatinine, plasma and kidney tissue malondialdehyde (MDA) were carried out, after the last dose of gentamicin. Kidneys were also examined for morphological changes. Gentamicin caused marked nephrotoxicity as evidenced by increase in blood urea, serum creatinine and decreased in creatinine clearance. Blood urea and serum creatinine was increased by 883% and 480% respectively with gentamicin compared to control. Carvedilol protected the rats from gentamicin induced nephrotoxicity. Rise in blood urea, serum creatinine and decrease in creatinine clearance was significantly prevented by carvedilol. There was 190% and 377% rise in plasma and kidney tissue MDA with gentamicin. Carvedilol prevented the gentamicin induced rise in both plasma and kidney tissue MDA. Kidney from gentamicin treated rats, histologically showed necrosis and desquamation of tubular epithelial cells in renal cortex, whereas it was very much comparable to control with carvedilol. In conclusion, carvedilol with its antioxidant property protected the rats from gentamicin-induced nephrotoxicity.

Adrenergic beta-Antagonists↗
PubMed2000

Oxidant stress and essential fatty acids in patients with risk and established ARDS.

Oxygen free radicals are important mediators of both physiological and pathological events. In acute lung injury, the activated lymphocytes stimulate tumor necrosis factor (TNF) and other cytokines. These lymphokines augment free radical generation by polymorphonuclear leukocytes (PMNLs), macrophages and other cells which may ultimately produce acute respiratory distress syndrome (ARDS). This is supported by our results presented here in that there is a significant increase in lipid peroxidation products in patients with established ARDS. The amount of lipid peroxidation was significantly higher in the established ARDS group compared to patients who are at risk for ARDS. Nitric oxide concentrations were significantly decreased in established ARDS compared to the control and those who are at risk for ARDS. Fatty acid analysis of the plasma phospholipid fraction revealed a significant decreased in linoleic acid, gamma-linolenic acid, dihomo-gamma-linolenic acid and arachidonic acid levels of n-6 series and alpha-linolenic acid, eicosapentaenoic acid, docosa-hexanenoic acid of n-3 series. Patients who are at risk for ARDS have decreased levels of gamma-linolenic acid of the n-6 series, alpha-linolenic acid and eicosapentaenoic acid of the n-3 series. These results suggest that lipid peroxides and alteration in essential fatty acid metabolism may have a role in the pathogenesis of ARDS.

Arachidonic Acid↗
PubMed2000

Ginkgo biloba extract ameliorates gentamicin-induced nephrotoxicity in rats.

The effect of Ginkgo biloba (EGb), a plant extract with an antioxidant effect, has been studied on gentamicin-induced nephrotoxicity in male wistar rats. Ginkgo biloba extract (300 mg/kg BW) was administered orally 2 days before and 8 days concurrently with gentamicin (80 mg/kg BW). Saline treated animals served as control. Estimations of urine creatinine, glucose, blood urea, serum creatinine, plasma and kidney tissue MDA were carried out after 8 days of gentamicin treatment. Kidneys were examined using histological techniques. Blood urea and serum creatinine were increased by 896% and 461% respectively, with gentamicin, compared to saline treated group. Creatinine clearance was significantly decreased with gentamicin. Ginkgo biloba extract protected rats from gentamicin-induced nephrotoxicity. Changes in blood urea, serum creatinine and creatinine clearance induced by gentamicin were significantly prevented by Ginkgo biloba extract. There was a 177% and 374% rise in plasma and kidney tissue MDA with gentamicin, which were significantly reduced to normal with Ginkgo biloba extract. Histomorphology showed necrosis and desquamation of tubular epithelial cells in renal cortex with gentamicin, while it was normal and comparable to control with Ginkgo biloba extract. These data suggest that supplementation of Ginkgo biloba extract may be helpful to reduce gentamicin nephrotoxicity.

Administration, Oral↗
PubMed2000

Melatonin, a pineal hormone with antioxidant property, protects against gentamicin-induced nephrotoxicity in rats.

The present study investigated the effects of melatonin, an antioxidant, on gentamicin-induced nephrotoxicity in rats. Melatonin (5 mg/kg p.o.) was used 3 days before and 8 days simultaneously with gentamicin (80 mg/kg i.p.) Saline-treated animals served as controls. Determinations of urinary creatinine, N-acetyl-beta-D-glucosaminidase, glucose, protein, blood urea, serum creatinine, plasma and kidney tissue malondialdehyde (MDA), and antioxidant enzyme levels in kidney tissue were done after 8 days of gentamicin treatment. The kidneys were also examined for morphological changes using histological techniques. Gentamicin caused nephrotoxicity as evidenced by marked elevation in blood urea and serum creatinine. Mean blood urea and serum creatinine levels were 289+/-50, and 2.5+/-0.5 mg/dl, respectively, in rats treated with gentamicin. Melatonin significantly protected the rats from gentamicin-induced nephrotoxicity; blood urea and serum creatinine levels were 23+/-2.7 and 0.88+/-0.19 mg/dl, respectively. The creatinine clearance was decreased with gentamicin treatment (0.048+/- 0.007 ml/min) as compared with controls (0.41+/-0.08 ml/h/kg). In rats treated with melatonin plus gentamicin, the creatinine clearance was similar to controls (0.41+/-0.08 ml/h/kg). The product of lipid peroxidation (MDA) was markedly increased in plasma (2.10+/-0.15 nmol) and kidney tissue (8.87+/-3.2 nmol/mg protein) with gentamicin treatment. Melatonin prevented the gentamicin-induced rise in plasma MDA (1.03+/-0.27 nmol) and kidney tissue MDA (2.57+/-0.87 nmol/mg protein). An increased excretion of urinary N-acetyl-beta-D-glucosaminidase, glucose, and protein by gentamicin was also prevented by melatonin. Kidneys from gentamicin-treated rats showed tubular epithelial loss with intense granular degeneration involving more than 50% of renal cortex, while there were findings comparable to controls in melatonin plus gentamicin treated rats. The present study indicates that melatonin significantly protects against gentamicin-induced renal toxicity in Wistar rats.

Animals↗
PubMed2000

Cytotaxonomic evidence for the presence of Anopheles nivipes in India.

Anopheles philippinensis mosquitoes were collected from 5 states in India: Assam, Meghalaya, Arunachal Pradesh, Manipur, and Nagaland. Half-gravid females were examined for variations in wing venation using the presector dark mark on vein I and polytene chromosomes derived from ovarian nurse cells. Polytene chromosomes were examined for diagnostic inversions, t on chromosome arm 2 and I on arm 5. Based on wing characteristics, both An. philippinensis and An. nivipes were identified. Polytene chromosome examinations revealed that all specimens from these 2 populations had 2t; 51 inversion genotype, a diagnostic character for An. nivipes. The wing character was not diagnostic; therefore, it was concluded that all the specimens examined were actually An. nivipes and not An. philippinensis. Further, the X chromosome was of x+b type, that is, the standard arrangement with reference to the inversion b, reported in the An. nivipes population in Thailand. This is the 1st report that unequivocally establishes the occurrence of An. nivipes in India and also shows that the adult wing character is not reliable in distinguishing An. philippinensis from An. nivipes, as has been observed in Thailand.

Animals↗
PubMed2000

Effect of pentoxifylline on cyclosporine-induced nephrotoxicity in rats.

Effect of unique hemorrheologic agent pentoxifylline (PTX) was investigated on cyclosporine (CsA) induced nephrotoxicity in rats. Compared to saline control, CsA produced significant increase in blood urea and serum creatinine. Pentoxifylline treatment prevented the CsA-induced rise in blood urea and serum creatinine. Creatinine clearance (Ccr) and lithium clearance (Licr) was decreased with CsA. PTX treatment prevented the CsA-induced decrease in Ccr and Licr. Malondialdehyde (MDA) was increased with CsA compared to saline treated animals. PTX prevented the CsA-induced MDA rise. Kidney form CsA treated rat showed marked vacuolar degeneration of tubular epithelium with excess of microcalcification. Severity of the lesions was markedly reduced in rats treated with PTX plus CsA. The results indicate that PTX reduces CsA-induced renal toxicity in rats.

Animals↗
PubMed1999

Melatonin: an antioxidant protects against cyclosporine-induced nephrotoxicity.

BACKGROUND: Cyclosporine (CsA) causes a dose-related decrease in renal function in experimental animals. Different mediators for CsA nephrotoxicity have been suggested; oxygen free radicals are one of them. In experimental model of Wistar rats, the role of antioxidant melatonin (Mel), the main product of pineal secretion, was investigated in CsA nephrotoxicity. METHODS: Male Wistar rats were divided into four groups: saline control, 50 mg/kg CsA, 500 microg/kg Mel, and CsA + Mel. At the end of 14th day of treatment, blood urea, creatinine, malondialdehyde, and creatinine and lithium clearance were estimated. Histopathological examination of kidney from all the groups was performed. RESULTS: CsA caused marked elevation in blood urea, serum creatinine, and plasma malondialdehyde and a decrease in creatinine and lithium clearance. Mel significantly antagonized CsA-induced renal impairment. Microcalcification in corticomedullary junction seen with CsA was prevented by Mel. CONCLUSION: These results indicate that Mel, through its antioxidant properties, provides protection against CsA-induced nephrotoxicity.

Animals↗
PubMed1999

Lacidipine protects against cyclosporine-induced nephrotoxicity in rats.

The effect of lacidipine (LA), a new calcium channel blocker with an antioxidant effect, has been studied on cyclosporine (CsA)-induced nephrotoxicity in male Wistar rats. Lacidipine (1 mg/kg BW) was administered orally 3 days before and 14 days concurrently with CsA (50 mg/kg BW orally). Urine volume, Na+, K+, Li+ and creatinine in urine, and blood urea, serum creatinine, lithium, plasma malondialdehyde (MDA) and CsA levels were estimated in blood after 14 days CsA treatment. Kidneys were examined using histological techniques. Blood urea and serum creatinine were increased by 305 and 211%, respectively, with CsA when compared to the saline-treated animals. Creatinine clearance (Ccr) and lithium clearance (Licr) were decreased and proximal tubule fractional reabsorption 1-(Licr/Ccr) was significantly increased with CsA. Lacidipine protected rats from CsA-induced nephrotoxicity. Changes in blood urea, serum creatinine, Ccr, Licr and proximal tubule fractional reabsorption induced by CsA were significantly prevented by LA. There was a 160% rise in MDA levels with CsA, which was significantly reduced equal to control with LA. Histomorphology showed microcalcification with CsA, while it was normal with LA. In rats treated with LA, CsA did not show any microcalcification. Our data suggest that supplementation of LA may be helpful to reduce CsA nephrotoxicity.

Animals↗
PubMed1998

Comparison of methods of eye protection under general anaesthesia.

PURPOSE: To compare and assess the efficacy of eye ointment and adhesive tape for protection of eyes under general anaesthesia. METHODS: One hundred and fifty patients (300 eyes) undergoing general anaesthesia for > 90 min for non-ophthalmic procedures were divided randomly into three groups (C, T & O). Eyes in group C were left as control, in group T hypoallergen tape was applied and in group O chloromycetin ointment was used. In all eyes basal tear production and visual acuity was assessed and corneal examination was carried out after fluorescein staining both before and after surgery. All the patients were subjected to a conventional general anaesthesia technique. RESULTS: General anaesthesia reduced basal tear production irrespective of the method of eye protection used (P < 0.0001). The overall incidence of corneal epithelial defects was 10%, of which 90% occurred in the control group, 6.6% in the tape and 3.3% in the ointment group. There was no difference between pre and post operative visual acuity (P : NS). Corneal injuries were more common in the dependent eye in the lateral position and the incidence of corneal epithelial defects did not alter with increase in duration of surgery. CONCLUSION: During general anaesthesia eyes need protection either by tape or ointment as incidence of corneal injuries is greater in unprotected eyes.

Adhesives↗
PubMed1997

Effect of cis-unsaturated fatty acids, prostaglandins, and free radicals on angiotensin-converting enzyme activity in vitro.

Angiotensin-converting enzyme (ACE) is known to play an important role in the pathobiology of human essential hypertension. Similarly, cis-unsaturated fatty acids, prostaglandins, and free radicals are believed to play a role in the control of blood pressure. It was observed that all the cis-unsaturated fatty acids tested can inhibit ACE activity to a significant degree. On the other hand, prostaglandins and free radicals, superoxide anion, hydrogen peroxide, and hydroxyl radical did not show significant inhibitory effects on ACE activity in vitro. But, the nitric oxide donor sodium nitroprusside showed a potent inhibitory action on ACE activity, suggesting that one of the possible mechanism(s) by which nitric oxide can bring about its anti-hypertensive action might be by modulating ACE activity in addition to its direct vasodilator action. These results indicate that there is a close interaction among ACE activity, cis-unsaturated fatty acids, and nitric oxide, which may have relevance to the pathobiology of human essential hypertension.

Adult↗
PubMed1996

A probabilistic model of hypobaric decompression sickness based on 66 chamber tests.

One consequence of the NASA tissue ratio (TR) model is that calculated probability of decompression sickness [P(DCS)] is constant in tests at different ambient pressures so long as the ratio of P1N2 to P2 is the same in each test; P1N2 is N2 pressure in the 360 minute half-time compartment, and P2 is ambient pressure after decompression. We test the hypothesis that constant P(DCS) is better described by TRs that decrease as P2 decreases. Data were from 66 NASA and USAF hypobaric chamber tests resulting in 211 cases of DCS in 1075 exposures. The response variable was presence or absence of DCS while at P2. Explanatory variables were P1N2, P2, exercise at P2, (yes or no), time to DCS (failure time), and time to end of test in those without DCS (censored time). Probability models were fitted using techniques from survival analysis. The log likelihood for the two parameter log logistic survival model was -846 with only failure and censored times, -801 when TR [P1N2/P2] plus exercise were added, and -663 when modified TR [(((P1N2+cl)/P2)-1)c2] plus exercise were added, where c1 and c2 are fitted parameters in the five parameter model. Constant P(DCS) was better described by TRs that decrease as P2 decreases; a conclusion supported by additional empirical observations, and bubble growth models that are independent of DCS data. Exercise increased the P(DCS) at P2. As a description of decompression "dose", the modified TR was superior to TR over a wider range of experimental conditions.

Adult↗
PubMed1995

Prostaglandin metabolism during growth and differentiation of the regenerating vertebrate appendage.

House lizards are able to regenerate their tails. This is an ideal model to study the growth and differentiation of an organ. Prostaglandins (PGs) are local hormones having diverse and potent biological activities. In an effort to understand PG metabolism during the growth and differentiation of the regenerating lizard tail, we analysed the fatty acid (FA) composition of phospholipids are free FAs by GC, the activity of two rate-limiting enzymes (phospholipases A and C), the activity of the enzyme responsible for the oxygenation of polyunsaturated fatty acids to PGs (cyclooxygenase) and characterized the endogenous PGs by HPLC. It was observed that on the 20th day, i.e. the tissue differentiation period, there was an increase in phospholipase A activity, together with a sudden fall in the free arachidonic acid (AA) level, an increase in cyclooxygenase activity and the appearance of endogenous PGE2. PGE2 can stimulate cyclic adenosine monophosphate (cAMP) production and it may stimulate a cascade of events associated with tissue differentiation.

Animals↗