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Biomedical subjects

J Rana

Publications and source records attributed to J Rana.

10 recordsLinked to original sources
PubMed2002

Bioactivity of alkamides isolated from Echinacea purpurea (L.) Moench.

Alkamides from the roots of Echinacea purpurea (L.) Moench were examined for anti-inflammatory activity in an in vitro model system. Cyclooxygenase-I (COX-I) and cyclooxygenase-II (COX-II) inhibitory activities were assessed at pH 7 for alkamides isolated from E. purpurea roots to compare inhibitory activities between the two cyclooxygenase isozymes. At 100 microg/ml, several E. purpurea alkamides inhibited COX-I and COX-II enzymes in the range of 36-60% and 15-46%, respectively, as compared to controls. Mosquitocidal activity was assessed at 100 and 10 microg/ml, with 100% mortality against Aedes aegyptii L. larvae noted for several E. purpurea alkamides at 100 microg/ml.

Aedes↗
PubMed2001

Separation, identification, quantification, and method validation of anthocyanins in botanical supplement raw materials by HPLC and HPLC-MS.

A method has been established and validated for identification and quantification of individual, as well as total, anthocyanins by HPLC and LC/ES-MS in botanical raw materials used in the herbal supplement industry. The anthocyanins were separated and identified on the basis of their respective M(+) (cation) using LC/ES-MS. Separated anthocyanins were individually calculated against one commercially available anthocyanin external standard (cyanidin-3-glucoside chloride) and expressed as its equivalents. Amounts of each anthocyanin calculated as external standard equivalent were then multiplied by a molecular-weight correction factor to afford their specific quantities. Experimental procedures and use of a molecular-weight correction factors are substantiated and validated using Balaton tart cherry and elderberry as templates. Cyanidin-3-glucoside chloride has been widely used in the botanical industry to calculate total anthocyanins. In our studies on tart cherry and elderberry, its use as external standard followed by use of molecular-weight correction factors should provide relatively accurate results for total anthocyanins, because of the presence of cyanidin as their major anthocyanidin backbone. The method proposed here is simple and has a direct sample preparation procedure without any solid-phase extraction. It enables selection and use of commercially available anthocyanins as external standards for quantification of specific anthocyanins in the sample matrix irrespective of their commercial availability as analytical standards. It can be used as a template and applied for similar quantification in several anthocyanin-containing raw materials for routine quality control procedures, thus providing consistency in analytical testing of botanical raw materials used for manufacturing efficacious and true-to-the-label nutritional supplements.

Anthocyanins↗
PubMed2001

Development of differential tolerance to the sedative and anti-stress effects of benzodiazepines.

Differential degree of tolerance has been reported to develop for anticonvulsant, sedative and skeletal muscle relaxant effects of benzodiazepines (BZDs). Acute treatment with BZDs reportedly reduces the formation of gastric stress ulcers and attenuates stress-induced immunosuppression. The present study investigates whether tolerance develops to these antistress effects of BZDs by using diazepam and chlordiazepoxide as representative drugs. A single dose of diazepam (5 mg/kg, i.p.) or chlordiazepoxide (20 mg/kg, i.p.) produced a significant reduction in locomotor activity, a measure of sedative effect and antagonized the effect of restraint stress (RS) on gastric mucosal lesions and anti-sheep red blood cell (SRBC) antibody titre. With chronic treatment (X 7 d), there was a marked tolerance to the sedative effect of both the studied BZD drugs, while much less tolerance developed to their ulcer protective action. However, no tolerance was observed to the attenuating effect of diazepam and chlordiazepoxide on RS-induced immunosuppression. Thus, the results of the present study indicate that different mechanisms may be involved in the development of tolerance to the sedative, antiulcer and immunomodulatory effects of BZDs.

Animals↗
PubMed1995

Adverse perinatal outcome in patients with an abnormal umbilical coiling index.

OBJECTIVE: To evaluate perinatal outcome in neonates with hypocoiled and hypercoiled cords. METHODS: From February 18 through June 13, 1994, 635 placentas from deliveries of at least 24 weeks' gestation were examined for umbilical coiling. The umbilical coiling index was calculated by dividing the total number of coils by the length of the cord. Subjects with umbilical coiling indices below the tenth percentile, above the 90th percentile, and between the tenth and 90th percentiles were defined as hypocoiled, hypercoiled, and normocoiled, respectively. Subjects with hypocoiled and hypercoiled cords were compared with those found to have normocoiled cords. Twelve different characteristics were used to measure perinatal outcome. RESULTS: The subjects with hypocoiled cords differed from those with normocoiled cords in two significant ways: rates of fetal heart rate (FHR) disturbances and interventional delivery were higher in the hypocoiled group (28.6 versus 15.9% [P = .01] and 19 versus 7.1% [P = .002], respectively). The subjects with hypercoiled cords compared with those found to have normocoiled cords had a higher rate of premature delivery (33.3 versus 12.0% [P < .0001] and a higher incidence of cocaine use (12.7 versus 3.3% [P = .0006]). CONCLUSION: Hypocoiled cords can be predictors of potential interventional delivery and intrapartum FHR disturbances. Hypercoiled cords are associated with an increased incidence of premature delivery and maternal cocaine use.

Adult↗
PubMed1990

Improving the outcome of cervical cerclage by sonographic follow-up.

A total of 39 patients with the diagnosis of cervical incompetence were followed up with cervical sonography after placement of prophylactic McDonald cerclage. During the first year of study, 3 out of 12 patients treated with prophylactic cerclage demonstrated funneling of the internal cervical os when examined with cervical sonography; all 3 had premature deliveries. During the last 3 years of the study, 8 of 27 patients treated with prophylactic cerclage demonstrated funneling. With active intervention, neonatal survival improved to 100%. Sonography aids in the management of patients with cervical incompetence and improves outcome even after placement of cervical cerclage.

Adult↗
PubMedDate not supplied

Synthesis of [3,5-14C]trachelanthamidine and [5-3H]isoretronecanol and their incorporation into the retronecine moiety of riddelliine in Senecio riddellii.

(+/-)-[3,5-14C]Trachelanthamidine and (+/-)-[5-3H]isoretronecanol, which are diastereomers, were prepared from potassium [14C]cyanide and [5-3H]proline, respectively. These compounds and [1,4-14C]putrescine were administered to Senecio riddellii plants resulting in the formation of labeled riddelliine, in which almost all the radioactivity was located in its retronecine moiety. The activity of the beta-alanine obtained by degradation of the retronecine was consistent with specific labeling of this pyrrolizidine base at the expected positions. The extremely high absolute incorporation (15.1, 22.1%) of trachelanthamidine into riddelliine strongly favors this 1-hydroxymethylpyrrolizidine as the one on the main biosynthetic pathway to retronecine. The lower incorporation (0.75%) of isoretronecanol may represent a minor or aberrant pathway to retronecine.

Carbon Radioisotopes↗
PubMedDate not supplied

Neuromuscular blocking drug pharmacodynamics after chronic exposure to H2- antagonists.

This study tested the hypothesis that chronic exposure to H2-antagonists may affect neuromuscular function. Cimetidine or ranitidine was administered to rats for twenty one days as subcutaneously implanted biodegradable pellets. Control rats received placebo pellets. Serum cimetidine and ranitidine concentrations ranged from 0.1 to 0.5 micrograms/mL over this period. On the study day, surgically prepared anaesthetized rats received either succinylcholine (SCh) or atracurium (ATr) to achieve complete paralysis of the tibialis anterior muscle. After recovery an infusion dose of each neuromuscular blocker was titrated to produce 50% muscle paralysis with each blocker. Exposure to cimetidine or ranitidine did not alter SCh or ATr dose to maximum paralysis or the time course of recovery from the initial paralysis. SCh or ATr infusion rates required to elicit 50% paralysis were also unaffected by cimetidine or ranitidine pretreatment. These results indicate that chronic exposure to cimetidine or ranitidine at human therapeutic concentrations does not affect the neuromuscular pharmacodynamics of SCh or ATr in rats.

Animals↗