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Biomedical subjects

R K Patel

Publications and source records attributed to R K Patel.

51 records · Page 3Linked to original sources
PubMed1994

Ethanol potentiates the clastogenicity of pan masala--an in vitro experience.

The significance of the interaction between alcohol and tobacco in causing head and neck cancers is well documented. Our previous reports on in vitro studies using aqueous and organic extracts as well as cytogenetic studies among pan masala consumers have conclusively shown the genotoxic potential of pan masala--a dry mixture of the areca nut, lime, catechu, unspecified flavouring agents, etc., often containing tobacco in it and is widely consumed in India. Now in the present report, the clastogenic effect of ethanol and pan masala in different combinations was evaluated on Chinese hamster ovary cells utilizing chromosome aberration (CA) frequency as an endpoint. An ethanol concentration of up to 2.0% had no effect on CA/cell value. The low-dose continuous treatment and high-dose short-term pre-, post- and simultaneous treatment of ethanol and aqueous extract of pan masala with and without tobacco yielded dose-dependent elevations in CA frequency, compared to any of these two substances alone. Thus, these results provide evidence that alcohol consumption may potentially increase the risk of oral cancer among pan masala chewers.

Animals↗
PubMed1994

Evaluation of chemopreventive effects of betel leaf on the genotoxicity of pan masala.

The antigenotoxic effect of the aqueous extract of betel leaf (BL-ext.) against the pan masala was tested with the help of cytogenetic endpoints like chromosome aberration (CA) and sister chromatid exchange (SCE) utilizing Chinese hamster ovary (CHO) cells. Compared to the cultures treated with aqueous extract of pan masala alone, a reduction in CA and SCE frequencies in CHO cells was observed following a combined treatment with pan masala (with or without tobacco) extract and BL-ext. The protective effect of BL-ext. against the genomic damage caused by pan masala was statistically significant only after treating the cells for a longer period.

Animals↗
PubMed1993

Children with persistent feeding difficulties: an observational analysis of the feeding interactions of problem and non-problem eaters.

This study examined the relationship between parent's feeding practices and the feeding behavior of toddlers and preschool-age children with (n = 19) or without (n = 29) persistent feeding difficulties. Specifically, patterns of parent-child interaction were assessed during standardized family mealtime observations in the clinic. Parents also kept observational records of their children's mealtime behavior at home and rated the degree of difficulty they experienced in feeding their child during each meal on a daily basis. Observational results showed that feeding-disordered children engaged in higher levels of disruptive mealtime behavior (food refusal, noncompliance, complaining, oppositional behavior, and playing with food) and lower levels of chewing during mealtime. There were several significant age effects, with younger children (under age 3) engaging in more vomiting and less aversive demanding and verbalizations. Parents of feeding-disordered children were more negative and coercive in their feeding practices and engaged in higher levels of aversive instruction giving, aversive prompting, and negative eating-related comments. There were several significant associations between coercive parental behaviors and children's food refusal and noncompliance in the sample as a whole. Measures of children's disruptiveness at mealtimes in the clinic were significantly correlated with measures of mealtime behavior in the home.

Behavior Therapy↗
PubMed1992

Chromosome damaging effects of pan masala.

Effects of aqueous extracts of a popular brand of pan masala with and without tobacco (PM-T and PM) were studied for short duration treatment employing an in vitro system. Metabolic activation with S9 mix was also included. Frequency of all the three cytogenetic endpoints viz., chromosome aberration (CA); sister chromatid exchange (SCE) and % micronucleated cells (% MNC) were found to be elevated significantly in a dose-dependent manner in cultures without metabolic activation. However, addition of S9 activation system resulted in suppression of chromosomal damage. Our findings indicate that pan masalas contain water soluble direct acting mutagens.

Animals↗
PubMed1992

Typhoid Vi: a less reactogenic vaccine.

A typhoid vaccine derived from the purified Vi capsular polysaccharide (CPS) antigen of Salmonella typhi was compared with a heat-killed whole-cell typhoid vaccine in 637 healthy male volunteers. The individuals were placed in three groups: group 1 received two doses of heat-killed whole-cell typhoid vaccine, at an interval of 28 days; group 2 received a single dose of typhoid Vi CPS vaccine followed after 28 days by water for injection; and group 3 received water for injection on the first occasion and a single dose of typhoid Vi CPS vaccine 28 days later. Local and systemic adverse reactions were recorded for 5 days following each injection. Subjects receiving the typhoid Vi CPS vaccine complained of fewer local adverse reactions on each of the first 3 days following immunization: on day 1, 18.6% of subjects given typhoid Vi CPS vaccine reported local reactions compared with 59.7% of those receiving heat-killed whole-cell vaccine (P less than 0.001). The percentage of subjects receiving the heat-killed whole-cell vaccine who complained of systemic reactions was more than twice that of subjects receiving the Vi CPS vaccine (7.9% and 3.4%, respectively, on day 1; P less than 0.01).

Adult↗
PubMed1991

Pharmacokinetic and tolerance studies of cefpodoxime after single- and multiple-dose oral administration of cefpodoxime proxetil.

Cefpodoxime proxetil, a third generation, broad-spectrum, oral cephalosporin, was administered in single doses of 100, 200, 400, 600, and 800 mg (dose expressed as cefpodoxime equivalents) and multiple doses of 100, 200, and 400 mg twice daily to healthy volunteers. The pharmacokinetics of the active metabolite, cefpodoxime, and tolerance of cefpodoxime proxetil were determined. Results from the single-dose study indicate that cefpodoxime exhibits nonlinear pharmacokinetics over the dose range of 100 to 800 mg. This nonlinearity is primarily due to differences in dose-normalized AUC and Cmax, urinary recovery, and half-life between one or more of the higher-dose treatment groups and the 100-mg dosing group. After multiple-dose (twice daily) administration for 15 days, steady state is achieved on the second day of dosing, and there is no drug accumulation. Cefpodoxime pharmacokinetics are linear with dose over the clinically relevant dosing range of 100 to 400 mg. Microbiologic and HPLC plasma assay results are highly correlated, with close agreement between HPLC- and microbiologic-determined pharmacokinetic parameter estimates. Cefpodoxime proxetil was well tolerated in both studies. The most frequent medical events were related to gastrointestinal problems and consisted of transient loose stools in three subjects in the single-dose study and antibiotic-associated diarrhea in one subject in the multiple-dose study.

Administration, Oral↗
PubMed1991

Lifestyle changes in mild asthma during intermittent symptom-related use of terbutaline inhaled via 'Turbohaler'.

Beta 2-agonist therapy effectively relieves asthmatic symptoms, but an improvement in patient lifestyle has not been demonstrated. This open study in which patients acted as their own controls, assessed the efficacy and acceptability of intermittent symptom-related use of terbutaline inhaled via 'Turbohaler', and its influence on the lifestyle of 1133 inhaler-naive, mild asthmatics treated in general practice. A 1-week run-in period was followed by 4-weeks' treatment with inhaled terbutaline (500 micrograms as required). Peak expiratory flow rate (PEFR) and 'Turbohaler' technique were assessed at clinic visits. Diary cards, completed daily, assessed: the number of terbutaline inhalations, the relief obtained after use, the severity of asthma symptoms (cough, morning wheeze, nocturnal wheeze and wheeze on activity), and lifestyle indices (sleep disturbance, work/school days lost, limitation of normal activity). After terbutaline treatment, PEFR increased by 54 +/- 2 l/min (p less than 0.001), the severity of asthma symptoms was almost halved (p less than 0.001), with over two-thirds (65% to 76%) of patients reporting improvements in each variable, and the adverse effect of asthma on lifestyle was at least halved (p less than 0.001). Improvements in lung function, asthma symptoms and lifestyle were comparable for all sub-groups: adults (greater than 16 years), school-age children (6 to 16 years) and preschool children (less than or equal to 5 years). This study not only confirmed the efficacy and acceptability of intermittent symptom-related use of terbutaline inhaled via 'Turbohaler', but also demonstrated that its use enhanced patients' lifestyles.

Activities of Daily Living↗
PubMed1990

Pharmacokinetics of cefpodoxime in plasma and skin blister fluid following oral dosing of cefpodoxime proxetil.

The single-dose and steady-state pharmacokinetics of cefpodoxime were assessed in plasma and skin blister fluid (SBF) after oral dosing of 200 mg (n = 8) and 400 mg (n = 8) of cefpodoxime proxetil (doses are expressed as cefpodoxime equivalents) in healthy subjects in an open-label, parallel-design study. Skin blisters were formed by air suction on the midvolar forearm by a previously validated method. After single-dose administration, serial plasma and SBF samples were collected over 24 h for measurement of cefpodoxime by microbiological assays. After a 1-week washout, subjects received the same doses of antibiotic every 12 h for 5 days, with plasma and SBF sampling on day 5. After 200 mg of cefpodoxime proxetil, average peak concentrations (Cmax) in plasma and SBF were 2.18 +/- 0.52 and 1.55 +/- 0.59 micrograms/ml, respectively, after a single dose and 2.33 +/- 0.74 and 1.56 +/- 0.55 micrograms/ml, respectively, at steady state. After 400 mg of cefpodoxime proxetil, Cmax in plasma and SBF averaged 4.16 +/- 1.04 and 2.94 +/- 0.71 micrograms/ml, respectively, following a single dose and 4.10 +/- 0.95 and 2.84 +/- 0.88 micrograms/ml, respectively, at steady state. Cmax occurred 1.1 to 1.6 h later in SBF than in plasma. There was no accumulation of cefpodoxime in plasma or SBF when dosing was done every 12 h. Cefpodoxime blister fluid penetration was estimated to be 67 to 101%, consistent with the relatively low serum protein binding of the drug. Cefpodoxime levels exceeding the MIC for 90% of many skin pathogens, such as Streptococcus species (<1 microgram/ml) or Staphylococcus species (2 to 4 micrograms/ml), were achieved in plasma and SBF following the 200- and/or 400-mg dosing regimens.

Administration, Oral↗
PubMed1989

The effects of gastric pH and food on the pharmacokinetics of a new oral cephalosporin, cefpodoxime proxetil.

The effects of alteration of gastric pH and food on the pharmacokinetics of 200 mg doses of cefpodoxime proxetil tablets were studied in two separate randomized, open label, crossover studies in healthy subjects. In the pH study (n = 17 subjects), there was a lead-in period done under fasting conditions, followed by randomization to a four-way crossover of pentagastrin (6 micrograms/kg, subcutaneously), ranitidine (150 mg orally, 10 and 2 hours before dosing with the antibiotic), sodium bicarbonate (12.6 gm), or aluminum hydroxide (120 cc). Gastric pH was determined by nasogastric aspirates before and 10 minutes after the intervention, just before the antibiotic was given. Peak plasma concentrations (Cmax) and area under plasma concentration-time curve (AUC) were highest in fasting and pentagastrin periods and were 35% to 50% lower for all of the other periods (p less than 0.0001). Gastric pH and Cmax and AUC were inversely related (r = 0.66 and r = 0.62; p less than 0.0001 for both). In the food study (n = 16 subjects), there were two lead-in periods, one done while subjects were fasting and one while they were normal diet, followed by randomization to a four-way crossover of either high or low protein diets, or high or low fat diets. There were six meals in each diet. Dosing with the antibiotic was done at the midpoint of the fourth meal. Cmax and AUC were 22% to 34% higher for all diets than for the fasting period (p less than 0.0001), whereas the time to Cmax was unchanged. These studies demonstrated that absorption of cefpodoxime proxetil is best at low gastric pH or in the presence of food, which suggests that the role of gastrointestinal function on the pharmacokinetic profile is complex.

Administration, Oral↗
PubMedDate not supplied

Comparison of ketoprofen, piroxicam, and diclofenac gels in the treatment of acute soft-tissue injury in general practice. General Practice Study Group.

The efficacy, tolerability, and acceptability of topical applications of ketoprofen gel (2.5% w/w), piroxicam gel (0.5% w/w), and diclofenac gel (1% w/w), when administered three times daily for 5 days, in the treatment of acute (within 48 hours) soft-tissue injury, were compared in an open-label, randomized, multicenter, general practice study. Of 1575 patients recruited, 1048 received ketoprofen gel (525 used the gel with a dose-measuring device), 263 received piroxicam gel, and 264 received diclofenac gel. Ketoprofen gel was significantly superior to piroxicam gel in terms of global assessment of treatment response (improvement in 74% vs 65% of patients) and the severity of the injury (38% vs 26% "greatly improved") and in improvements in stiffness (71% vs 64%), restriction of mobility (34% vs 22%), and pain on pressure (81% vs 78%) and movement (83% vs 77%). Ketoprofen gel also compared favorably with diclofenac gel, with a larger proportion of patients assessing a great improvement in the injury (38% vs 30%). Patient acceptability of ketoprofen gel was significantly better than piroxicam gel. More patients noted a significant cooling effect with ketoprofen gel (71%) than with either piroxicam gel (49%) or diclofenac gel (60%). Ketoprofen gel also showed excellent tolerability. In conclusion, ketoprofen gel may offer benefits over established therapies for the treatment of acute soft-tissue injury.

Acute Disease↗