Destruction of phagocytosis-suppressing activity of aflatoxin B1 by ozone

The impact of ozone on the immunity-impairing activity of aflatoxin B1 (AFB1) was studied. Phagocytosis by rat peritoneal macrophages, which was found to be suppressed in the presence of AFB1, remained unimpaired when the applied AFB1 was pretreated with ozone (1.2 mg l-1) for 6 min at a flow rate of 40 ml min-1. Hence, application of ozone on AFB1-contaminated foodcrops seems to be a promising preventive measure against any adverse immunological disorder in consumers.

Biochemical activities of denatured covalently closed circular duplex DNA

Covalently closed circular duplex DNA when exposed to high alkaline pH followed by neutralization yields a collapsed state structure (form I(d)) that can undergo transition to form I and was susceptible to S1 nuclease. Form I(d), in spite of its compact structure, admits specific cleavage by restriction enzymes over its entire genome. When used in a semi-in vitro replication complex, form I(d) gave significantly better template activity, and undergoes better primer extension in in vitro using Klenow. Thus form I(d) having a compact shape can behave as a better substrate in a few key enzymatic reactions.

Mechanism of blood sugar lowering by a swerchirin-containing hexane fraction (SWI) of Swertia chirayita

Mechanism of blood sugar lowering by the crude/impure swerchirin (SWI) isolated from the hexane fraction of Swertia chirayita was investigated. Single oral administration of SWI (50 mg/kg, body wt) to fed CF rats induced about 60% (max.) fall in blood glucose by 7 hr post-treatment. This was associated with marked depletion of aldehyde-fuchsin stained beta-granules and immunostained insulin in the pancreatic islets. In vitro, glucose uptake and glycogen synthesis by muscle (diaphragm) was significantly enhanced by the serum of SWI-treated rat. At 100, 10 and 1 microM final concentration, SWI greatly enhanced glucose (16.7 mM)-stimulated insulin release from isolated islets. It is therefore concluded that SWI lowers blood glucose level by stimulating insulin release from islets of Langerhans.

Swerchirin induced blood sugar lowering of streptozotocin treated hyperglycemic rats

Effect of Swerchirin (1:8 dihydroxy 3:5 dimethoxy xanthone) isolated from hexane fraction of Swertia chirayita on the blood sugar level of healthy and streptozotocin treated rats was studied. Streptozotocin was administered in citrate buffer (pH-4.5) intravenously / 35 and 65 mg/kg body wt to Charles Foster strain albino rats. Swerchirin (50 mg/kg, po) suspended in gum acacia was fed through cannula to the above rats and to a group of healthy rats. Blood sugar estimated at 0, 1, 3 and 7 hr after, indicated a very significant lowering in healthy and streptozotocin (35 mg/kg iv) but not in streptozotocin (65 mg/kg) treated rats.

Hypoglycemic effect of swerchirin from the hexane fraction of Swertia chirayita

A xanthone was isolated from the hexane fraction of the Swertia chirayita plant and identified as 1,8-dihydroxy-3,5-dimethoxyxanthone (swerchirin). It has a very significant blood sugar lowering effect in fasted, fed, glucose loaded, and tolbutamide pretreated albino rat models. The ED50 for 40% blood sugar lowering in CF male albino rats (body weight 140-165 g) is 23.1 mg/kg/oral. The possibility of its application in clinical therapy for diabetes mellitus needs exploration.

Hypoglycemic activity of Swertia chirayita (Roxb ex Flem) Karst

Hexane fraction of S. chirayita (250 mg/kg body wt.) induced significant fall in blood sugar and significant increase in plasma IRI simultaneously after single oral administration without influencing liver glycogen concentration in albino rats. On the other hand, daily administration for 28 days resulted in significant lowering of blood sugar and increase in plasma IRI along with a significant rise in liver glycogen. Intestinal absorption of glucose was not inhibited by hexane fraction. It is suggested that hexane fraction of S. chirayita possibly acts through its insulin releasing effect.

Potassium induced insulin release from isolated islet of Langerhans of albino rats

The secretory effect of Potassium (K+) on endocrine pancreas was studied using collagenase digested isolated islets of Langerhans. Isolated islets of Langerhans incubated in KRB containing 5 15, 30 and 45 mM, quantity of additional K ions caused the release of insulin from beta-cells (significant release of insulin, P less than 0.01, at 15, 30 and 45 mM K+ in presence of 2.8 mM glucose and at 30 mM K in presence of 16.7 mM glucose). But lysosomal AP and CB enzymes did not record proportionate change. Thus a definite stimulation in the release of insulin without significant change in AP and CB were seen.

Effect of various organic compounds on synthesis of glucoamylase by an isolated strain Penicillium italicum

Yeast extract (0.5%) stimulates the production of glucoamylase and cell synthesis while methylene blue (0.1 mM) activates the synthesis of glucoamylase. Studies on the metabolic changes during fermentation of glucoamylase in a selected medium by P. italicum show that the rate of production of glucoamylase and cellular growth are greatly accelerated between 48 and 168 hr. Rapid growth of cells during this period may account for enhanced utilization of maltose and NH4NO3 from the medium. The acid production remains constant from 48 to 144 hr. Different forms of nitrogen decrease steadily. Although methylene blue stimulates the production of glucoamylase in the broth it has practically no effect on the rate of utilization of amino and total nitrogen from the broth.

Effect of herbicide banvel on rabbit vaginal mucus membrane

Effect of banvel and its active ingredient, dicamba (3,6-dichloro-o-anisic acid) was investigated employing rabbit mucus membrane irritancy test. Inflammatory changes which did not exceed an average score of 2+ were observed in the animals 48 hr after a single intravaginal application of banvel (0.1 ml/rabbit) and dicamba (100 mg/rabbit). Persistent histopathological changes were observed in 1 out of 6 banvel-treated rabbits 15 days post-application. The results suggest that banvel and dicamba are not primary irritants but should nevertheless be employed with caution.

Blood sugar lowering potentiality of selected Cucurbitaceae plants of Indian origin

Using five experimental models, the blood sugar lowering efficacy of eight plants of Cucurbitaceae family has been assessed. The ethanolic extract of Cucumis sativus Linn, Cucumis melo utilissimum Roxb, Cucumis melo Linn, Benincasa hispida Thunb Cogn and Tricosanthes anguina Nees, when administered in 250 mg/kg dose, orally to rats failed to lower blood sugar or to depress the peak value, after glucose load. However, ethanolic extract of Momordica charantia Linn plant and Coccinia indica Whit and Arn root significantly lowered blood sugar in fasted model and depressed the peak value in glucose loaded model. Ethanolic extract of Tricosanthes dioica Roxb plant caused a significant lowering of blood sugar in fasted rats and depressed the peak value in glucose loaded single and longterm fed groups of rats. The ethanolic extract of the aerial part of T. dioica also induced significant depression in the peak values in the glucose loaded models.

Effects of prednisolone and dexamethasone on (pro)insulin biosynthesis and insulin release by rat islets of Langerhans

Administration of either prednisolone or dexamethasone (10 mg/kg body wt/day/oral) to rats for 21 days resulted in inhibition of (pro)insulin biosynthesis and immunoreactive insulin release by isolated islets. A gradual reversal of prednisolone's effect was obtained after exposing islets to increasing glucose concentrations but glucose challenges failed to influence dexamethasone's effect.

Changes in pancreatic beta cell function during growth and reproductive maturity of rats

An attempt has been made to study the changes, if any, in the efficiency of pancreatic beta cell function at different ages using one experimental model. For this, pancreatic islets were isolated from albino rats of 3, 8, 12 and 36 weeks of age and challenged with various concentrations of glucose (11.0, 16.7 and 22.2 mM). Significantly higher rate of glucose stimulated (pro)insulin biosynthesis was seen in the islets from 3 week old rats as compared to the islets obtained from 8, 12 and 36 week rats. On the other hand, immunoreactive insulin release was observed to be highest from islets of 8 week old rats followed by that of 12, 36 and 3 week old ones.

Anti-secretagogue effect of lithium on isolated rat islets of Langerhans

Administration of lithium carbonate solution (50 mg/kg, po, twice daily) to Charles Foster male albino rats for 45 consecutive days caused an intolerance to oral glucose. Inhibition in (pro)insulin biosynthesis followed by a significant fall in immunoreactive insulin release was seen in islets isolated from identically treated rats. As the activities of acid phosphatase and cathepsin B were unaltered, it is possible that the anti-secretagogue effect is sequential to inhibition of (pro)insulin biosynthesis by lithium.

Effect of prolonged administration of cyclosporin A on (pro)insulin biosynthesis and insulin release by rat islets of Langerhans

One group of rats received, an oral dose of 25 mg/kg body weight of Cyclosporin A daily for 21 consecutive days in olive oil, whereas the control group received an equal amount of the vehicle for the same period. On the 22nd day animals selected at random from both the groups were subjected to glucose tolerance (1.5 g/kg body weight/oral). The blood sugar values indicated glucose intolerance in experimental rats compared to vehicle-treated rats. The remaining animals were killed, and the pancreases were separated for islet isolation. After incubation of islets for 3 hr at 37 degrees with different glucose challenges, a highly significant (P less than 0.001) lowering of (pro)insulin biosynthesis, significant decrease in IRI release as well as significant inhibition in activities of acid phosphatase and cathepsin B was seen.

Accelerated fracture union in association with severe head injury

Union occurred unusually rapidly in 13 fractures of long bones in 11 patients who had sustained severe head injuries. Possible metabolic mechanisms for this are discussed and it is suggested that respiratory alkalosis associated with severe head injury or its treatment affects the rate of deposition of callus by modifying the pH at the fracture site. Fractures in patients with severe head injuries should be restored to an acceptable position early in order to avoid malunion.

Effect of whole body gamma-radiation on glutathione reductase of rat tissues

Adult female Sprague Dawley rats approximate ten months old were exposed to whole body gamma radiation of sublethal (4 Gy) and lethal (10 Gy) doses of radiation. Serum glutathione reductase enzyme values of 4 Gy exposed rats did not show any change on first and fourth day but significantly decreased on eighth day, while enzyme values in 10 Gy exposed group remained unaltered throughout. Heart glutathione reductase activities of sublethal group did not show any change on first and eighth day but significantly decreased on fourth day. Rats exposed to lethal doses of radiation, enzyme activities remained unchanged throughout. Liver glutathione reductase enzyme values of 4 Gy exposed group showed significant decrease on first and fourth day but arrived at control values on eighth day while the same in 10 Gy exposed group showed significant decrease from first day till the eighth day. An appreciable diminution was observed in spleen glutathione reductase enzyme activities of sublethal and lethal exposed rats from first day till eighth day.

Mutagenic evaluation of tolbutamide and glybenclamide on the bone marrow cells of mice

Mutagenicity of tolbutamide (TB) and glybenclamide (GL) was evaluated in vivo by the micronucleus test (MNT) in mice. Various doses of either TB or GL, as suspension in 1% gum-acacia, were orally administered to the animals, twice, at an interval of 24 h. 6 h after the second treatment, bone-marrow smears were prepared, stained and examined for the occurrence of micronucleated erythrocytes. Animals receiving the vehicle only, served as control. TB only at two higher dose levels induced significant increase in the percentage of micronucleated erythrocytes over that of the control, but GL failed to do so.

Effect of epinephrine and norepinephrine on immuno-reactive insulin secretion from isolated islets of Langerhans

Earlier studies have demonstrated the inhibitory nature of epinephrine and norepinephrine on pancreatic insulin release. The present study reports their effect on beta-cell IRI release in an isolated islet system. Results show that epinephrine and norepinephrine inhibit islet-IRI release at the 100-10 microM level. The alpha adrenergic blocker phentolamine (100 microM) but not the beta adrenergic blocker propranolol (100 microM) can reverse this catecholamine induced inhibition of islet-IRI release. This clearly suggests that epinephrine and norepinephrine inhibit insulin release via alpha-adrenergic pathway.

Effects of SITS on urate transport by isolated, perfused snake renal tubules

Effects of an inhibitor of membrane anion-exchange transport processes, 4-acetamido-4'-isothiocyano-2,2'-disulfonic stilbene (SITS), on urate transport by isolated, perfused snake (Thamnophis spp.) proximal renal tubules were studied. SITS (10(-4) mol/l) in the luminal perfusate had absolutely no effect on net urate secretion (Jneturate) or on net fluid absorption (JV). This observation is compatible with other data that give no support to the concept of a mediated transport step for urate from the cells to the lumen. SITS (10(-4) mol/l) in the bathing medium reversibly inhibited Jneturate without affecting JV. At the time of maximum inhibition of Jneturate, the concentration of urate in the cell water was increased and the apparent permeability of the luminal membrane to urate was decreased, but the urate efflux across the peritubular membrane and the apparent permeability of the peritubular membrane to urate were unchanged. There was no evidence of significant intracellular binding or trapping of urate. Although an increase in the initial rate of urate transport into the cells across the peritubular membrane could not be demonstrated conclusively in nonperfused tubules, the results still suggest that SITS in the bathing medium may inhibit Jneturate by inhibiting urate movement from the cells to the lumen while actually enhancing transport from the bathing medium into the cells.

In vivo mutagenic effect of methyldopa. 1. Dominant lethal test in male mice

The dominant lethal test was used to evaluate the mutagenic potential of methyldopa, an antihypertensive drug, in male mice. In the series treated, animals were exposed to 480 or 960 mg/kg of the drug as a suspension in 1% gum acacia via the oral route. A separate group of males served as control. Following treatment each male of the control, as as well as the treated series, was mated to two untreated virgin females each week for a period of 6 consecutive weeks. All mated females were sacrificed on the 10th day of separation and their ovaries and uterine contents were examined. Corpora lutea, implantations and resorptions were recorded. The drug treatment did not impair the mating capacity and fertility. Pre- and post-implantation losses were assessed. Higher incidences of post-implantation losses and abortion, and lower incidences of total implantations particularly at higher dose levels clearly reveal a dominant lethal effect of the drug.

Isolation of bacteria producing chloramphenicol acetyltransferase from soil and their characterization

After screening 107 soil samples collected from different spots around Calcutta, 579 chloramphenicol resistant colonies were isolated. Out of these only 58 colonies could inactivate chloramphenicol in detectable amounts. By noting the production of inactivating factor, 5 high yielding strains were further characterized to species level. Three of them were Escherichia coli strains, the two others were Alcaligenes faecalis and Klebsiella pneumoniae strains. All strains inactivated chloramphenicol by acetylation, with the production of chloramphenicol acetyltransferase. Production of this latter enzyme was not inducible. Minimum inhibitory concentrations for these 5 strains were studied against 14 antimicrobial agents. All strains were found to be resistant to most antimicrobial agents, but sensitive to polymyxin B. The strain A. faecalis was also sensitive to carbenicillin but other four strains were resistant to this antibiotic.

Insulinotropic action of L-rhamnose in isolated rat islets

L-Rhamnose at different concentrations stimulated incorporation of 3H-leucine both into islet (pro)insulin and that released into the medium. Maximum isotope incorporation with either glucose or rhamnose was seen at a concentration of 16.7 mM, although the glucose-induced effect was significantly greater. Like glucose, rhamnose also enhance the activities of acid phosphatase and cathepsin B in isolated rat islets.

Mechanisms of hemodynamic actions of furosemide: differentiation of vascular and renal effects on blood pressure in functionally anephric hypertensive patients

To differentiate diuretic and direct cardiocirculatory properties of furosemide for elucidation of the vasodepressor mechanisms of action of the agent in the acute treatment of hypertension, the peripheral vascular effects of intravenous furosemide (3 mg/kg) on supine blood pressure (BP) and forearm hemodynamics in 11 functionally anephric hypertensive patients (creatinine clearance less than 2 ml/min) were studied. BP was recorded by sphygmomanometer and forearm hemodynamics were measured by strain gauge plethysmography. While diastolic BP decreased only 2.7 mm Hg at 30 minutes, forearm blood flow increased 55% (p less than 0.01) mediated by decreased peripheral vascular resistance of 30% (p less than 0.01) at 15 minutes which dissipated by 30 minutes. Systolic BP, indices of venous capacity, weight, hematocrit, serum electrolytes, and plasma renin activity were unchanged. No diuresis occurred. It is concluded that the early hypotensive effect of furosemide depends upon diuresis.

Excision arthroplasty for tuberculous and pyogenic arthritis of the hip

Thirty patients with chronic pyogenic or tuberculous arthritis of the hip treated by Girdlestone's excision arthroplasty were reviewed two to seven years after operation. There was marked or complete relief of pain in 29, control of infection in 27, squatting and sitting cross-legged was possible in 27, and 16 were able to stand on the operated limb. Overall results were good in 16, fair in nine, and poor in five. Tuberculous disease was not reactivated and the use of traction for 12 weeks and a weight-relieving caliper for 12 months after operation helped to reduce the shortening to an average of 3.8 centimetres. Excision arthroplasty is considered a sound operation to restore the ability to squat and sit cross-legged.