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Biomedical subjects

R Ranjan

Publications and source records attributed to R Ranjan.

At least 19 recordsLinked to original sources
PubMed2007

Pharmacokinetic profile of erythromycin after intramammary administration in lactating dairy cows with specific mastitis.

The pharmacokinetics of erythromycin was studied in five lactating dairy cows following single intramammary infusion of 300 mg erythromycin in each of two quarters per cow with specific mastitis. Levels of erythromycin in plasma and quarter milk samples were measured by agar plate diffusion assay using Micrococcus luteus (ATCC 9341) as the test organism. Erythromycin level in plasma reached a peak concentration value (C(max)) of 0.07 +/- 0.01 microg/ml at 30 min; thereafter, levels declined gradually to reach 0.05 +/- 0.00 microg/ml 12 h post drug administration. The pharmacokinetic profile of the drug revealed mean absorption half life (t(1/2 ka)) as 0.26 +/- 0.05 h. The drug was eliminated slowly with elimination half-life (t(1/2 beta)) of 13.75 +/- 0.35 h and elimination rate constant (k(el)) of 0.04 +/- 0.00 h(-1). The volume of distribution based on the zero-time plasma concentration intercept of the least-squares regression line of the elimination phase (V(d(B))) was 0.032 L/kg. The drug crossed to untreated quarters also; mean drug levels of 0.20 +/- 0.07, 0.23 +/- 0.07, 0.17 +/- 0.04, and 0.17 +/- 0.04 microg/ml were found at 3, 6, 8 and 12 h, respectively. The mean drug concentration for treated quarters was measured as 22.97 +/- 2.31 microg/ml milk at first milking (12 h) following drug infusion. No apparent adverse reaction was seen in cows administered erythromycin. It is concluded that following intramammary infusion erythromycin diffuses readily and extensively in various body fluids and tissues and adequate concentration is maintained in udder tissues for at least 12 h post intramammary administration. Thus, erythromycin may be recommended for local therapy of acute mastitis caused by Gram-positive bacteria in lactating dairy cows.

Animals↗
PubMed2007

Prenatal diagnosis of haemophilia A by chorionic villus sampling and cordocentesis: all India Institute of Medical Science experience.

BACKGROUND AND OBJECTIVE: We looked at the two most commonly used methods for prenatal diagnosis, cordocentesis and chorionic villus sampling for prenatal diagnosis of haemophilia A in an Indian setting. MATERIAL AND METHODS: The study sample included 16 families which reported to us for prenatal diagnosis of haemophilia A at All India Institute of Medical Science, New Delhi, India. Prenatal tests were done on chorionic villus samples or on cord blood (cordocentesis). Molecular work-up included the use of indirect mutation analysis in the form of linkage markers like CA-13, CA-22, Xba1 and Bcl1 as well as direct mutation analysis in the form of inversion 1 and 22 detection. Non-molecular work-up included primarily factor VIII assays. RESULT: Chorionic villus sampling was performed in eight mothers. Of the other eight mothers, six underwent cord blood factor VIII assays because these had absence of family history and were negative for linkage and inversion 1 and 22. One patient had a female child and another had a fetus that showed congenital abnormalities. CONCLUSION: We found that the choice of either technique, chorionic villus or cordocentesis, is not really an alternative, but rather dependent on the gestational age of presentation.

Chorionic Villi Sampling↗
PubMed2006

Erythrocyte lipid peroxides and blood zinc and copper concentrations in acute undifferentiated diarrhoea in calves.

Undifferentiated acute calf diarrhoea is a major concern for the dairy industry and its aetiopathogenesis remains diverse. The present study aimed to examine the role of oxidative stress through estimation of erythrocyte lipid peroxide levels and blood zinc and copper concentrations using natural cases of diarrhoea in calves aged 15-30 days old. The calves were kept under identical managemental conditions and were provided with pooled whole colostrum during the first three days and thereafter with only whole milk until they were 1 month old. Diarrhoeic (n = 11) and normal calves (n = 11) of the same age group (15-30 days old) were randomly selected from an organized dairy farm for the study. The mean blood zinc concentration (50.01+/-2.45 mumol/L vs 66.06+/-3.06 mumol/L) was significantly (p < 0.05) lower and copper concentration was significantly (p < 0.05) higher in diarrhoeic calves (12.90+/-0.31 mumol/L vs. 9.44+/-0.16 mumol/L) than in the healthy calves. The erythrocyte lipid peroxides level was higher (p < 0.05) in diarrhoeic calves (6.88+/-0.23 nmol malondialdehyde (MDA) per mg of haemoglobin (Hb)) than healthy calves (6.27+/-0.07 nmol MDA per mg Hb). From the results of the study it is concluded that oxidative stress and antioxidant minerals (zinc and copper) might play important roles in the aetiopathogenesis of bovine calf diarrhoea.

Acute Disease↗
PubMed2005

Enhanced erythrocytic lipid peroxides and reduced plasma ascorbic acid, and alteration in blood trace elements level in dairy cows with mastitis.

Oxidative stress has been associated in several inflammatory conditions and incriminated in the pathogenesis of many diseases. However, little information is available on the status of plasma antioxidant levels, essential components of important antioxidant enzymes such as copper, zinc and selenium in blood, and the end product of oxidative damage to the erythrocytic polyunsaturated fatty acids in inflammatory udder conditions. Blood samples were collected from three groups of dairy cows, with 21 in each group: animals with healthy udder, clinical mastitis, and subclinical mastitis. These animals were randomly selected from a herd on the basis of the California mastitis test, somatic cell count and total bacterial count. The mean plasma ascorbic acid concentration was significantly lower in cows with subclinical (p = 0.004) and clinical mastitis (p = 0.000) and the erythrocytic lipid peroxide levels were significantly (p = 0.000) higher in clinical mastitis as compared to controls. There was a significant decrease in mean blood zinc concentration in subclinical (p = 0.005) and clinical mastitis (p = 0.000), but an increase in mean blood copper level in the clinical mastitis group. It was concluded that the blood antioxidant status declines in inflammatory udder conditions, suggesting that incorporation of antioxidants may help in better management of mastitis in dairy cows.

Animals↗
PubMed2005

Acupressure for prevention of pre-operative anxiety: a prospective, randomised, placebo controlled study.

Pre-operative anxiety is associated with many unwanted effects such as increased analgesic and anaesthetic requirement, postoperative pain and prolonged hospital stay. In the present study, we investigated the effects of acupressure on pre-operative anxiety and bispectral index (BIS) values. Seventy-six adults, ASA grade I and II, undergoing elective surgery, were randomly assigned to two equal groups. Group 1 (control) received acupressure at an inappropriate site and group 2 (acupressure) received acupressure at extra 1 point. The study was conducted during the pre-operative period and the duration of the study was 40 min (acupressure was applied for 10 min and thereafter patients were observed for another 30 min). Anxiety was recorded on a visual stress scale (VSS) at the start of the study and thereafter at 10 and 40 min. BIS was recorded at 0, 2, 5, 10, 12, 15, 30 and 40 min. The VSS decreased in both groups following pressure application for 10 min: median VSS (interquartile range) were 5 (1) vs. 8 (1) in the acupressure and 7 (0) vs. 8 (1) in the control groups (p < 0.001). Both pre-operative anxiety and BIS decreased significantly during acupressure application at extra 1 point (p < 0.001). Acupressure is effective in decreasing both pre-operative anxiety and BIS; however, these effects are not sustained 30 min following release of acupressure. Further studies are needed to elucidate the duration for which acupressure is effective.

Acupressure↗
PubMed2005

Enhanced erythrocytic lipid peroxides level in rabbits after repeated parental administration of iron.

An experiment was conducted in rabbits to evaluate the possible involvement of oxidative stress in iron-overload animals. Ten adult female New Zealand white rabbits were divided into 2 equal groups with 5 animals each. Group II animals received intramuscular iron dextran injections (120 mg/kg body wt/day) on alternate day for 14 days (8 injections), while Group I animals did not receive any iron supplementation to serve as negative controls. The blood samples were collected by cardiac puncture before the start of iron dosing and thereafter, at weekly intervals for 28 days. The samples were processed to measure blood iron concentration, packed cell volume, erythrocytic lipid peroxide (LPO) level, superoxide dismutase (SOD) and catalase (CAT) activities. The blood iron concentration showed a rising trend following repeated iron administration, and the mean level recorded on day 14 was significantly higher than respective day 0 value. LPO level remained significantly higher from day 14 onwards till the end of the observation period of 14 more days after cessation of iron adminstration. Erythrocytic superoxide dismutase activities showed a transient significant rise on day 7, and thereafter, showed a declining trend, but remained statistically comparable to respective day 0 or corresponding value of the control animals.

Animals↗
PubMed2004

Pain during injection of propofol: the effect of prior administration of ephedrine.

Propofol causes pain on intravenous injection in 28 to 90% of patients. A number of techniques have been tried to minimize propofol-induced pain, with variable results. In a randomized, double-blind, placebo-controlled trial, we compared the efficacy of ephedrine 30 microg/kg pretreatment to lignocaine 40 mg for prevention of propofol-induced pain. Ninety-three adult patients, ASA 1 and 2, undergoing elective laparoscopic cholecystectomy were randomly assigned to three groups of 31 each. Group 1 received normal saline, group 2 received lignocaine 2% (40 mg) and group 3 received 30 microg/kg ephedrine. All pretreatment drugs were made up to 2 ml. Pain at the time of propofol injection was assessed on a four-point scale: 0=no pain, 1 =mild pain, 2=moderate pain, and 3=severe pain. Twenty-seven patients (87%) of ephedrine pretreatment patients had pain during intravenous injection of propofol as compared to 24 (77%) in the normal saline group. In the lignocaine group, propofol-induced pain was observed in only 13 (42%) when compared with other study groups (P<0.05). Pretreatment with ephedrine 30 microg/kg did not attenuate pain associated with intravenous injection of propofol, nor did it improve haemodynamic stability during induction. However, pretreatment with 2% lignocaine (40 mg) was effective in attenuating propofol-associated pain.

Adolescent↗
PubMed2002

Lymphopenia in dialysis patients: a preliminary study indicating a possible role of apoptosis.

Lymphopenia is a common finding in dialysis patients. Since infection rate and mortality associated with infection are high in dialysis patients, lymphopenia may be one of the contributing factors. In the present study, we evaluated the mechanism responsible for lymphopenia in these patients. Lymphocytes isolated from dialysis patients showed increased apoptosis (p < 0.001) when compared to lymphocytes isolated from healthy subjects (healthy subjects, 0.5 +/- 0.2% vs. dialysis patients, 8.8 +/- 0.7% apoptotic cells/field). Sera from dialysis patients promoted lymphocyte apoptosis in a time- and dose-dependent manner. These sera also enhanced lymphocyte DNA fragmentation into multiple integers of 180 base pairs in the form of a ladder pattern. Cellulose acetate membranes promoted T cell apoptosis when compared to polysulfone membranes and to control. Cellulose acetate dialysis membranes also appear to promote lymphocyte FasL expression. Similarly, dialysis sera enhanced T cell Fas as well as FasL expression. Neither the cellulose acetate nor polysulfone membranes could induce FasL expression on B cells. Similarly, dialysis sera failed to induce FasL expression on B cells. On the other hand, anti-FasL antibodies attenuated dialysis sera-induced apoptosis in T as well as B cells. Interestingly, dialysis serum showed a 5-fold increase in FasL content when compared with control serum. These results suggest that dialysis-associated factors can induce autocrine death in T cells but the help of activated T cells is required to induce death in B cells.

Adult↗
PubMed2002

Monocyte apoptosis in dialysis patients is Fas ligand-mediated.

BACKGROUND: The mononuclear phagocyte system plays an important role in host defense. Since dialysis patients have been reported to show enhanced leukocytes apoptosis, we evaluated the mechanism of increased apoptosis of monocytes in dialysis patients. METHODS: Apoptotic studies were carried out on monocytes isolated from dialysis patients as well as healthy subjects. The effect of dialysis sera and membranes was evaluated on monocyte apoptosis as well as monocyte expression of proapoptotic proteins such as Fas and FasL. To confirm the role of FasL, we evaluated the effect of activated secretory products on T cell apoptosis. In addition, we studied FasL content of dialysis sera and supernatants of activated monocytes. RESULTS: Monocytes isolated from dialysis patients (MDP) showed a greater magnitude of apoptosis when compared to monocytes isolated from healthy subjects (MHS) (MHS, 3.6 +/- 1.1% vs. MDP, 24.3 +/-1.4%). Sera of hemodialysis patients (SHD) promoted (p < 0.001) apoptosis of MHS when compared to pooled control sera (HPS) (HPS, 0.8 +/- 0.5% vs. SHD, 11.5 +/- 0.5% apoptotic cells/field). Dialysis membranes, cellulose acetate membranes in particular, promoted monocyte apoptosis. Interestingly, anti-FasL antibodies partly inhibited dialysis sera-induced monocyte apoptosis. Dialysis membranes also modulated monocyte expression of both Fas and FasL. Secretory products of activated monocytes also promoted T cell apoptosis. Dialysis sera and activated monocyte secretory products showed increased FasL content. CONCLUSIONS: These results suggest that dialysis patients have an increased rate of monocyte apoptosis, which is mediated through a uremic milieu (serum factors). One of these serum factors seems to be FasL. In addition, dialysis membranes seem to promote apoptosis independent of the uremic milieu. The present study provides a mechanistical insight into the enhanced apoptosis of monocytes in dialysis patients.

Apoptosis↗
PubMed2001

Time trends in the occurrence and outcome of acute myocardial infarction and coronary heart disease death between 1986 and 1996 (a New Jersey statewide study).

Most reports of the decrease in age-adjusted coronary heart disease (CHD) are based on databases with upper age cut-offs that exclude approximately half of the events. We report changes in rates of acute myocardial infarction (AMI) and of out-of-hospital coronary death between 1986 and 1996 among New Jersey residents > or =15 years old. Data on patients discharged with the diagnosis of AMI from nonfederal acute care hospitals in the state (n = 270,091) and all records in the New Jersey death registration files with CHD (n = 172,175) listed as the cause of death from 1986 to 1996 (total study n = 442,266) were analyzed. The rate of hospitalized AMI cases in the state remained essentially unchanged during these 11 years, whereas in-hospital and 30-day case fatality among all age groups and both sexes declined. Age-adjusted CHD rates showed a decrease in fatal events, a smaller decrease in total events, and a slight increase in nonfatal events. The proportion of fatal CHD events occurring out-of-hospital decreased especially among men. The median age at occurrence of events increased by 1 year. Despite a decrease in CHD mortality, the rate of nonfatal events increased, especially among persons > or =75 years old. Thus, the decrease in age-adjusted CHD mortality is not all due to treatment and true prevention of CHD, but the disease simply occurs at an older age.

Adolescent↗
PubMed2001

Association of increased pulse pressure with the development of heart failure in SHEP. Systolic Hypertension in the Elderly (SHEP) Cooperative Research Group.

The aim of this study was to assess the relationship between pulse pressure (PP) and the occurrence of heart failure (HF) in older persons with isolated systolic hypertension. Data from a prospective, multicenter, randomized, double-blind, placebo-controlled clinical trial were analyzed. A total of 4736 persons aged > or = 60 years with systolic blood pressure (SBP) between 160 and 219 mm Hg and diastolic blood pressure (DBP) < 90 mm Hg who participated in the Systolic Hypertension in the Elderly Program (SHEP) were studied. The main outcome measures were fatal and nonfatal HF. During 4.5 years average follow-up, fatal or nonfatal HF occurred in 160 of 4736 patients. The SBP, PP, and mean arterial pressure (MAP) were strong predictors of the development of HF (P < .0002). Cox proportional hazards regression using time-dependent covariates and controlling for MAP indicated that HF was inversely related to DBP (P = 0.002) and was directly related to pulse pressure (P = 0.002). Data were similar when patients who developed myocardial infarction during follow up were excluded. These data indicate that, in older persons with isolated systolic hypertension, high pulse pressure is associated with increased risk of heart failure independently of MAP and of the occurrence of acute myocardial infarction during follow-up.

Aged↗
PubMed2001

Dialysis membrane-induced neutrophil apoptosis is mediated through free radicals.

Patients on hemodialysis are prone to infection. Neutrophils are the host's first line of defense against certain invading pathogenic microorganisms. Since apoptotic neutrophils are functionally compromised we examined the effect of dialysis membranes on neutrophil apoptosis. Dialysis patients showed greater (p < 0.001) neutrophil apoptosis when compared with control subjects. Cellulose acetate membranes directly promoted (p < 0.001) neutrophil apoptosis. Cellulose acetate membrane-treated neutrophils exhibited greater apoptosis (p < 0.01) when compared with polysulfone membrane-treated neutrophils. Superoxide dismutase (SOD) partly inhibited the cellulose acetate membrane-induced neutrophil apoptosis, whereas both catalase and dimethylthiourea (DMTU) inhibited the polysulfone membrane-induced neutrophil apoptosis. Similarly, L-NAME, a nitric oxide synthase inhibitor, attenuated both the cellulose acetate and the polysulfone membrane-induced neutrophil apoptosis. In addition, cellulose acetate and monocyte interaction products promoted (p < 0.001) neutrophil apoptosis. These results suggest that dialysis membranes can promote neutrophil apoptosis directly as well as through their interaction with monocytes. The direct effect of dialysis membranes seems to be mediated partly through the generation of reactive oxygen species.

Analysis of Variance↗
PubMed2001

Search for polyprenols in leaves of evergreen and deciduous Ericaceae plants.

Various species and cultivars of Ericaceae family were checked for the presence of long-chain polyprenols in their leaves. In the genus Rhododendron no polyprenols were found in the ever-green species, while they were present in the deciduous type. The polyprenols were of chain-length of 14-20 isoprene residues and they occurred in the form of acetic acid esters. The polyprenol accumulation is discussed with respect to senescence of leaves.

Chromatography, High Pressure Liquid↗
PubMed2000

Novel features of Sr1-xCaxTiO3 phase diagram: evidence for competing antiferroelectric and ferroelectric interactions

Structural and dielectric evidences are advanced to show that the Sr1-xCaxTiO3 (SCT) system undergoes an antiferroelectric (AFE) phase transition in the composition range 0.18</=x</=0.40. Stabilization of the AFE phase, instead of the ferroelectric (FE) phase known for 0<x<0.12, is shown to be intimately linked with the nonpolar antiferrodistortive phase transitions driven by the R and M point instabilities preceding the AFE transition. It is proposed that the disorder and frustration introduced by CaTiO3 substitution in the incipient FE matrix of SrTiO3 leads to the smearing of the varepsilon(')(T) response in SCT for 0.002<x<0.12 akin to dipole glasses and relaxor ferroelectrics.

Journal Article↗
PubMed1999

Overexpression of cysteine-string proteins in Drosophila reveals interactions with syntaxin.

Cysteine-string proteins (CSPs) are associated with secretory vesicles and critical for regulated neurotransmitter release and peptide exocytosis. At nerve terminals, CSPs have been implicated in the mediation of neurotransmitter exocytosis by modulating presynaptic calcium channels; however, studies of CSPs in peptidergic secretion suggest a direct role in exocytosis independent of calcium transmembrane fluxes. Here we show that the individual expression of various CSP isoforms in Drosophila similarly rescues the loss of evoked neurotransmitter release at csp null mutant motor nerve terminals, suggesting widely overlapping functions for each isoform. Thus, the structural difference of CSP variants may not explain the opposing putative functions of CSP in neurotransmitter and peptide exocytosis. Consistently, the individual overexpression of each CSP isoform in wild-type Drosophila shows similar effects such as impaired viability and interference with wing and eye development. The dominant effects caused by the overexpression of CSP are suppressed by the simultaneous overexpression of syntaxin-1A but not by the coexpression of SNAP-25. Although overexpression of CSP itself has no apparent effect on the synaptic physiology of larval motor nerve terminals, it fully suppresses the decrease of evoked release induced by the overexpression of syntaxin-1A. A direct protein-protein interaction of CSP with syntaxin is further supported by coimmunoprecipitations of syntaxin with CSP and by protein binding assays using recombinant fusion proteins. Together, the genetic and biochemical interactions of CSP and syntaxin-1A suggest that CSP may chaperone or modulate protein-protein interactions of syntaxin-1A with either calcium channels or other components of the regulatory machinery mediating depolarization-dependent neurotransmitter exocytosis.

Animals↗