Synthesis and characterization of novel tamarind gum and rice bran oil-based emulgels for the ocular delivery of antibiotics.

In this study, we developed tamarind gum (TG) and rice bran oil (RBO)-based emulgels. The control formulation (TR0), did not contain RBO. The emulgels were named as TR1, TR2, TR3, and TR4, which contained 5% (w/w), 10% (w/w), 15% (w/w), and 20% (w/w/) of RBO, respectively. The microscopic studies showed that the emulgels were biphasic in nature. FTIR spectroscopy revealed the reduction in the hydrogen bonding with an increase in the RBO content. Impedance profiles suggested that the resistive component of the emulgels was increased as the RBO content was increased. The thermal analysis suggested that the addition of RBO reduced the water holding capacity of the emulgels. Stress relaxation studies revealed that the fluidic component was considerably higher in TG/RBO-based emulgels as compared to TR0. In vitro release study of the model drug (ciprofloxacin HCl; a hydrochloride salt of ciprofloxacin) suggested a significantly lower release from the emulgel matrices (TR1-TR4) in comparison to TR0. However, ex vivo corneal permeation of the drug increased with an increase in the RBO content. Since the emulgels were able to improve the corneal permeation of the model drug, the emulgels can be explored to deliver drugs to the internal structures of the eye.

Fetal malnutrition and adult chronic disease.

Since the fetal origins of adult disease hypothesis was put forward, more than 30 studies around the world have indicated low-birth-weight (LBW) infants have a higher incidence of hypertension and impaired glucose tolerance. India ranks second in incidence of LBW among South East Asian countries and is experiencing a transition of disease pattern from communicable disease to non-communicable disease. Whether this could be explained in part by LBW infants who experienced better nutrition at a later age is explored here. An earlier cohort with accurate birth weights was traced and enrolled into the study. A sample of 50 LBW and 78 normal birth weight (NBW) individuals are reported on here. Though the odds ratio (OR) estimates of risk factors for coronary heart disease and diabetes tended to be higher in LBWs who were better nourished at the time of the study, they were not statistically different. Similarly, OR estimates for risk factors tended to be higher in LBWs who put on more weight than the median of NBWs, but they were not significant. Logistic regressions with several variables indicated significant influence of body mass index on systolic (P <0.007) and diastolic (P <0.004) blood pressures. Since the risk associations are weak, more studies are needed to put the hypothesis on a firm footing.

Field evaluation of biodegradable controlled release formulation of fenthion against Mansonia mosquitos.

Controlled release monolithic formulation of fenthion, an organophosphorus mosquito larvicide, prepared by the physical entrapment of the active agent into biodegradable polymer matrices was evaluated against Mansonia mosquito larvae breeding in hydrophytes infested coconut husk retting ponds. Field evaluation was carried out at two application rates viz, 2.5 and 1.0 ppm. Absolute control of larval breeding was observed for 25 and 17 weeks and over 50% reduction in breeding density was observed for another 3 and 2 weeks for the respective application rates of 2.5 and 1.0 ppm. The bioassay carried out with the water samples collected from the ponds treated at 2.5 ppm against the fourth instar larvae of Mansonia annulifera showed larval mortality of more than 95% for 14 weeks and 80-95% from 15 to 25th week. The concentration of fenthion in the treated ponds was found to vary between 0.006 and 0.095 ppm during the evaluation period.

Micronuclei and carcinogen DNA adducts as intermediate end points in nutrient intervention trial of precancerous lesions in the oral cavity.

In cancer chemoprevention trials, biomarkers as intermediate end points have gained importance. A variety of biomarkers have been proposed as intermediate end points for upper aerodigestive tract cancers. This study was aimed at studying the frequency of micronucleated cells and carcinogen DNA adducts as indicators of DNA damage and intervention end points in chemoprevention trials. Reverse smokers of chutta (rolled tobacco) from four villages numbering 298 in total were selected. Out of these, 150 were supplemented with four nutrients (vitamin A, riboflavin, zinc and selenium) and 148 controls received placebo, one capsule twice a week for 1 year. Slides of buccal smears were prepared and stained with Fuelgen reaction and counterstained with Fast Green and examined microscopically for the presence of micronucleated cells. Oral cell washings were collected and centrifuged. The DNA adducts were evaluated by the 32P post-labelling assay method. Protein and RNA free DNA (adducted) isolated from the cells was digested with MN/SPD and the DNA adducts isolated by the butanol enrichment procedure. The DNA adducts were identified and quantitated by multidimensional chromatography on PEI-TLC sheets by screen enhanced autoradiography and presented as RAL (relative adduct labelling) values. Both the micronuclei and DNA adducts were significantly elevated in subjects with lesions. At the end of 1 year the frequency of micronuclei decreased significantly (P < 0.001) in the supplemented subjects with or without lesions. The DNA adducts in the supplement group at the end of 1 year also reduced significantly. The adducts decreased by 95% in subjects with all categories of lesions and by 72% in subjects without lesions. No such effects were noted in the placebo group. The two biomarkers investigated in the case study appear to be modifiable by the administration of micronutrient supplements.(ABSTRACT TRUNCATED AT 250 WORDS)

A case study of nutrient intervention of oral precancerous lesions in India.

Tobacco chewing and/or smoking are strongly related to several cancers, mainly of the upper aerodigestive tract. Several studies on diet and cancer links suggest that micronutrients, particularly antioxidant vitamins and minerals, are risk modifiers of cancers of epithelial origin. This study looks at the impact of micronutrients such as vitamin A, riboflavin, zinc and selenium as intervention agents in subjects with and without precancerous lesions in a high risk group (reverse smokers of chutta-rolled tobacco leaf). Reverse smokers from four villages were enrolled in the study. 150 subjects were supplemented with four nutrients, namely vitamin A, riboflavin, zinc and selenium in the form of a capsule twice a week for 1 year. 148 controls received a placebo capsule containing lactose for the same period. Clinical history and anthropometric data were collected from all the subjects and a clinical photograph of the palate was taken. Micronutrients were estimated in random blood collected from a sub-sample before and after the study. Micronutrients improved the vitamin A, riboflavin and selenium nutriture in the supplemented group with a concomittant regression of precancerous lesions present on the palate. Clinically complete remission of white, red and combination lesions was seen in 57% of subjects on supplements whereas 8% on placebo showed a positive response. Further progression of these lesions was seen in 10% of the supplemented group compared with 47% in the placebo group (P < 0.001). In the non-lesion group, new lesions appeared in 12% on supplements while more than 38% on the placebo developed new lesions (P < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Diet and oral cancer - a case control study.

Apart from strong genotoxic carcinogens, other environmental factors are implicated in both causes and prevention of cancers. A hospital based case control study was conducted to examine the role of diet in the aetiology of oral and oropharyngeal cancers. In this article, past dietary intake and nutrient estimates, obtained through diet history method and biochemical nutritional status at the onset of the disease are presented. The results of the study suggest that poor dietary intake of vegetables and fruits coupled with low estimated intake of betacarotene, thiamine, riboflavin, folate, vitamin C, iron and copper, modify the risk potential. The biological indicators of the nutritional status such as plasma vitamin A, E, red cell folate and plasma zinc were significantly reduced in cases and yielded moderate risk estimates. The risk estimates though of moderate magnitude are of importance in relatively homogeneous subjects with respect to diet and nutrition. The findings are in line with several other epidemiological observations. The combined effects of micro nutrients appears to be protective in countering the adverse effects of exogenous exposures to tobacco. The protective role of vegetables and fruits is of potential interest in terms of etiologic causes and prevention.

N-nitrosamines in Indian beers.

Presence of volatile N-nitrosamines in beer and other alcoholic drinks are well documented in developed countries. Analysis of 120 beer samples of various brands/batches showed positivity for N-nitrosodimethylamine (NDMA) in more than 100 samples. The overall mean of 3.6 ppb of NDMA is higher than those currently found in Western countries. Since N-nitrosamines are proven carcinogens in animals at several sites it is necessary to keep their levels of exposure to as low as possible.

A case control study of selenium in cancer.

As selenium has been shown to be a risk modifier of cancer at several sites in a case-control approach, selenium nutriture was studied in oral and oesophageal cancer patients. The mean selenium level in oral cancer patients was 102.6 ng/ml and in oesophageal cancer 103.3 ng/ml, while in the matched controls it was 117.5 and 116.2 ng/ml respectively. Relative risk estimates were 3.16 (P < 0.02) and 16.0 (P < 0.01) in oral and oesophageal cancer patients respectively. The risk appears to increase with selenium levels lower than 115 ng/ml.

Esophageal cancer and diet--a case-control study.

It has been estimated that approximately 40% of human cancers may be associated with dietary factors. The relationship is more significant in esophageal cancers. Case-control studies involving 35 subjects of early-diagnosed esophageal cancers showed low mean blood levels of retinol, zinc (p less than 0.001), folic acid (p less than 0.01), and albumin (p less than 0.05). Relative risk was significantly higher for low levels of retinol and zinc. Diet, in general, in both groups reflected poor intake of several nutrients.

Development of environmentally compatible controlled release formulations of a mosquito larvicide.

A new controlled release system of a mosquito larvicide, fenthion has been developed by the chemical modification of sodium carboxymethylcellulose into a hydrophobic gel of copper carboxymethylcellulose. Four formulations having a slab geometry were developed with two concentrations of the larvicide and two extents of cross-linking. The release profile of the larvicide from the formulations was studied under laboratory conditions. The formulation with a cross-linking period for 48 h and a 20 per cent larvicide concentration with respect to the dry weight of the formulation has been found to be stable with a sustained release of the active ingredient for a period of 25 wk. The release profile of the formulation followed zero order release kinetics after three weeks in water. The concentration of fenthion ranged between 0.07 and 0.21 mg/l at the application rate of one slab per five litres of water with an average release rate of 6.38 mg/wk during the period of study.

Development & evaluation of controlled release formulations of DEPA, an insect repellent.

Three controlled release formulations of the insect repellent DEPA (N, N-Diethyl phenylacetamide), Depa-A, Depa-B and Depa-C have been developed and tested on human subjects against Aedes aegypti adult mosquitoes for repellency and the results were compared to those of a solution of DEPA (Depa-0). The increase in the protection time of the formulations, as compared to Depa-0 was compared. Depa-B was found to be effective with a protection time of 7.13 and 6.15 h and percentage increase in protection time of 44.5 and 38.2 at the two application rates of 0.5 and 0.25 mg/cm2 of the repellent. This observation agreed with the studies carried out on the evaporation of the repellent formulations on two models, on adsorbing and nonadsorbing surfaces for the relative adsorption and evaporation by analysing the repellent concentrations, using an infrared spectrophotometer.