Assessment of the impact strength of the denture base resin polymerized by various processing techniques.

Aim : To measure the impact strength of denture base resins polymerized using short and long curing cycles by water bath, pressure cooker and microwave techniques. Materials and Methods: For impact strength testing, 60 samples were made. The sample dimensions were 60 mm × 12 mm × 3 mm, as standardized by the American Standards for Testing and Materials (ASTM). A digital caliper was used to locate the midpoint of sample. The impact strength was measured in IZOD type of impact tester using CEAST Impact tester. The pendulum struck the sample and it broke. The energy required to break the sample was measured in Joules. Data were analyzed using Student's " t" test. Results: There was statistically significant difference in the impact strength of denture base resins polymerized by long curing cycle and short curing cycle in each technique, with the long curing processing being the best. Conclusion: The polymerization technique plays an important role in the influence of impact strength in the denture base resin. This research demonstrates that the denture base resin polymerized by microwave processing technique possessed the highest impact strength.

Drug Prescription Pattern in Pregnant Women Attending Antenatal Out Patient Department of a Tertiary Care Hospital.

Aims: Pregnant women requiring medication represent a challenge to healthcare providers to avoid any teratogenic risk to fetus. The purpose of this study was to provide information about the drug use among pregnant women in a tertiary care hospital, Mumbai, India. Study Design: Cross-sectional study. Place and Duration of Study: Department of Obstetrics and Gynecology and Department of Pharmacology, Seth GSMC & KEM Hospital, between July 2011 and December 2011. Methodology: A cross sectional study was conducted by reviewing the antenatal care Outpatient department case papers of 760 random pregnant women. Demographic profile, detailed medical history and drug intake in current pregnancy was noted. The prescription pattern was assessed and the drugs were classified based on the US FDA Risk Classification. Results: Out of 760 women, one third (33.18%) women were anemic. Majority drugs were prescribed for the treatment of upper respiratory tract infection, vaginal discharge fever with chills, nausea and vomiting. The average number of drugs per prescription was 2.27. Only 4% drugs were prescribed by their brand name and 96 % by generic name. Iron, folic acid and calcium were prescribed to all pregnant women. Majority of the patients were prescribed Category A and B drugs. No patient was given Category X drugs. Conclusion: Findings of our study showed that all pregnant women were provided with prophylactic iron and folic acid therapy. The occurrence of contraindicated medicines was desirably low, thereby minimizing overall risk to developing fetus. Thus prescribing pattern observed in our study sets a good example, as selection of drugs was rational in most of the cases.

The role of intensity-modulated radiotherapy in head and neck cancer.

Intensity-modulated radiotherapy (IMRT) has been a significant technological advance in the field of radiotherapy in recent years. IMRT allows sparing of normal tissue while delivering radical radiation doses to the target volumes. The role of IMRT for parotid salivary gland sparing in head and neck cancer is well established. The utility of IMRT for pharyngeal constrictor muscle and cochlear sparing requires investigation in clinical trials. The current evidence supporting the use of IMRT in various head and neck subsites has been summarized. Sparing of organs at risk allows for dose-escalation to the target volumes, taking advantage of the steep dose-response relationship for squamous cell carcinomas to improve treatment outcomes in advanced head and neck cancers. However, dose-escalation could result in increased radiation toxicity (acute and late), which has to be studied in detail. The future of IMRT in head and neck cancers lies in exploring the use of biological imaging for dose-escalation using targeted dose painting.

Novel therapeutic approaches to squamous cell carcinoma of the head and neck using biologically targeted agents.

Despite significant improvements in the treatment and outcomes of patients with squamous cell carcinoma of the head and neck (SCCHN) that have resulted from technological advances in radiation delivery and the use of cytotoxic chemotherapy, there is still a pressing need for novel therapies. In the last two decades, our understanding of the molecular biological basis of cancer has provided us with a new framework for developing specific targeted therapies. It is likely that the next wave of developments will include active small molecule inhibitors of epidermal growth factor receptor (EGFR) (and other members of the c-erbB family of receptors), antiangiogenic agents, and drugs that can increase proapoptotic signaling in cancer cells. As with cetuximab, it is most likely that these new agents will first find a niche in the context of combination regimens with standard anticancer therapeutics.

Influence of the processing technique on the flexural fatigue strength of denture base resins: An in vitro investigation.

Background : Though acrylic resins possess many desirable properties, denture fracture due to flexural fatigue or impact failure is a common problem. One major factor influencing the flexural fatigue strength of denture base resins is the processing technique used. Aim: To measure the flexural fatigue strength of denture base resins polymerized using short and long curing cycles using water bath, pressure cooker, and microwave polymerization techniques. Materials and Methods: Flexural fatigue strength of 60 samples (n=10) were measured using a cyclic 3-point loading method on a dynamic universal testing machine. Data were analyzed using a Student 't' test. Results : Comparative evaluation using Student's 't' test of mean flexural fatigue strength of samples processed by water bath processing (660.6) and the microwave technique (893.6) showed statistically significant (P <0.01) result with microwave processing being higher. Comparison of water bath (660.6) and pressure cooker (740.6) processing and microwave (893.6) and pressure cooker (740.6) processing using Student's 't' test was not statistically significant (P >0.05). In the intra-group analysis, it was found that there was statistically significant difference in samples processed using the short and long curing cycle, the latter being better in all groups, P-values being <0.05, <0.001, and <0.001 for water bath, microwave, and pressure cooker polymerization techniques, respectively. Conclusion : The polymerization procedure plays an important role in influencing the flexural fatigue strength of denture base resins, and the microwave long curing processing technique produced denture bases with highest flexural fatigue strength.

Pneumococcal hemolytic uremic syndrome.

We report Hemolytic Uremic Syndrome (HUS) induced by Streptococcus pneumoniae in a 20 month-old girl. She responded well to hemodialysis.

Plasmapheresis: an adjunct therapy in severe progressive neuropsychiatric lupus.

OBJECTIVE: We report our experience with use of plasmapheresis (PP) as an adjunct therapy in severe progressive neuropsychiatric systemic lupus erythematosus (NPSLE). METHOD: Three patients of NPSLE (including 2 with status epilepticus) who were progressively worsening on steroids or combination of pulse cyclophosphamide (CPM) and steroids were treated with PP followed by synchronized CPM. Pre and post treatment SLE Disease Activity Index (SLEDAI) and laboratory tests were carried out. RESULTS: Significant clinical improvement with decrease in SLEDAI occurred immediately following PP. Mean SLEDAI before and after PP were 33 and 11. Mean erythrocyte sedimentation rate decreased from 121 to 31. Rebound flare of disease activity noted in two patients between 7th-10th day requiring additional immunosuppressants or steroids. CONCLUSIONS: PP used as an adjunct therapy in severe, progressive NPSLE is well tolerated and can turn the patient around. PP should be followed by synchronized pulse CPM to prevent disease flare.

Protective effect of turmeric (Curcuma longa L.) extract on carbon tetrachloride-induced liver damage in rats.

The protective effect of tumeric extract (TE) in diet on CCl4-treated rats was studied. Rats were divided into 5 groups: (1) untreated, (2) CCl4 treated, (3) pre-TE for 2 weeks followed by CCl4, (4) TE + CCl4 given concurrently and (5) 5% TE as positive control. The serum levels of bilirubin, cholesterol, aspartate aminotransferase, (AST), alanine amino transferase (AST), (ALT) and alkaline phosphatase were estimated after 1, 2 and 3 months. CCl4 caused a maximum increase (2-3-fold in all the above parameters. As compared to CCl4 group, a short pre-treatment of TE showed reduction in cholesterol, bilirubin, AST, ALT and alkaline phosphatase activity whereas concurrent treatment of TE + CCl4 reduced to a greater extent the levels of all parameters except ALT. To conclude, concurrent treatment of TE gave significant protection against CCl4 though the values did not reach the normal levels.

Effect of country liquor (Indian alcoholic beverage) on carcinogen activating and detoxifying enzymes.

The levels of some important drug activating and detoxyfying enzymes were estimated in the livers of Swiss mice treated with a local brand of country liquor. Following liquor ingestion in male mice elevated levels of hepatic cytochrome P-450 were observed, while female mice did not show this. Cytochrome b5 levels remained unchanged. Similarly in male mice, increase in hepatic reduced glutathione levels were obtained while in female mice, decrease in this was observed. The activity of glutathione S-transferase was not changed. It is suggested that the increases in cytochrome P-450 and in hepatic reduced glutathione may be important determinants in carcinogenecity of the country liquors.

Carcinogenic potential of Indian alcoholic beverage (country liquor).

Epidemiological studies reveal that alcohol consumption is a risk factor for the cancer of the mouth, larynx, esophagus and various other organs. Of the various alcoholic beverages consumed in India, country liquors are widely consumed and that too by the economically weak section of the society. The present paper describes the experiments designed to investigate the effect of one brand of country liquor from Maharashtra State, India (which was found to be more potent in our earlier mutagenicity studies) for its carcinogenicity in two strains of mice and Syrian golden hamsters. The experimental animals received 10% liquor in drinking water from 2 months of age for 16 months. One percent ethanol treated animals served as positive controls. Together with long term bioassays, the transplacental carcinogenic effect of country liquor in the offspring of treated mothers, as well as in the breeders themselves was also investigated. Pregnant mothers were fed 10% liquor through drinking water from 12th day of gestation till weaning of the progeny. Then offspring were allowed to live without further treatment and mothers continued to get liquor treatment. In long term bioassays, liquor caused 22% total tumor incidence in male BALB/c mice and 28% in male Swiss mice. In female Swiss mice and in hamsters, liquor did not show any pronounced effect on tumor incidence. Similar negative results were obtained in case of offspring of treated mothers, but the offspring of liquor treated mothers had higher mortality prior to weaning as compared to those of untreated mothers.

Effect of 9,10-dimethyl-1,2-benzanthracene on the growth of hamster dermal fibroblasts in primary culture.

Newborn Syrian hamster dermal fibroblasts in primary culture have high plating efficiency, manifest as homogeneous contact-sensitive monolayer in mass cultures and above all possesses a short life-span of 15-20 days in culture. These cells are quite sensitive to mutagenic carcinogens. The DMBA treatment induced multi-layer and foci formation and growth in soft-agar suggesting that immortal variants can be obtained by treatment with carcinogens.

Mutagenicity and carcinogenicity of tea, Camellia sinensis.

Aqueous, caffeine free and tannin fractions of commercial tea and tannic acid were tested for mutagenicity in Ames test. Tea fractions of tannic acid were non mutagenic in strains TA 100, TA 98, TA 1535 and TA 1538 of Salmonella typhimurium with or without metabolic activation (rat-S9 mix) at different doses tested. In strain TA 98 the above tea fractions and tannic acid inhibited the S9 mix mediated mutagenicity of tobacco in a dose dependent manner. The different tea fractions at 60 degrees C, did not increase the tumor incidence in Swiss mice by gavage feeding. They also failed to produce tumors when injected subcutaneously. Caffeine free tea extract decreased the tobacco induced liver tumors but had no effect on lung tumors. The same fraction was ineffective in hexachlorocyclohexane induced liver tumors in Swiss mice.

Chemopreventive efficacy of betel leaf extract and its constituents on 7,12-dimethylbenz(a)anthracene induced carcinogenesis and their effect on drug detoxification system in mouse skin.

Effects of topically applied betel leaf extract (BLE) and its constituents. beta-carotene, alpha-tocopherol, eugenol and hydroxychavicol on 7,12-dimethylbenz(a)anthracene (DMBA) induced skin tumors were evaluated in two strains of mice. BLE, beta-carotene and alpha-tocopherol, significantly inhibited the tumor formation by 83, 86, 86% in Swiss mice and 92, 94 and 89% in male Swiss bare mice respectively. Hydroxychavicol showed 90% inhibition in Swiss bare mice at 24 weeks of treatment. Eugenol showed minimal protection in both strains of mice. The mean latency period and survivors in BLE, beta-carotene, alpha-tocopherol and hydroxychavicol treated groups were remarkably high as compared to DMBA alone treated group. Intraperitoneal injection of betal leaf constituents showed a significant effect on both glutathione and glutathione S-transferase levels in the Swiss mouse skin.

Species difference in intestinal drug metabolising enzymes in mouse, rat and hamster and their inducibility by masheri, a pyrolysed tobacco product.

Activities of several drug metabolising enzymes in the small intestine were investigated in Swiss mice, Sprague Dawley rats and Syrian Golden Hamsters fed 10% masheri, a pyrolysed tobacco product, in diet, for 20 months. The basal levels of enzymes in proximal (PI), medium (MI) and distal (DI) parts of the intestine in the three species were similar. However, the levels of cytochrome P-450, benzo(a) pyrene hydroxylase (B(a)OH) and glutathione S-transferase (GST) were highest in hamsters followed by rat and mice. Upon treatment with masheri, significant induction of cytochrome P-450 and B(a)PH was observed in PI and DI of all the three species. However, GSH and GST was depleted upon masheri treatment in all the three species again only in proximal and distal parts of the intestine. Thus increase in activating enzymes together with depletion in GSH-GST system upon exposure could be an important factor in the susceptibility of the small intestine to hazardous xenobiotic exposure.

Inhibitory effects of snuff extract on ornithine decarboxylase and aryl hydrocarbon hydroxylase activities in relation to cell proliferation of mouse tongue epithelial cells.

Effect of snuff extract (SE) on cell proliferation as measured by 3H thymidine (TdR) uptake, induction of ornithine decarboxylase (ODC) and aryl hydrocarbon hydroxylase (AHH) was studied in primary embryonal mouse tongue cultures. Cultures treated with SE in combination with 7,12-dimethylbenz(a)anthracene (DMBA) showed inhibition of cell proliferation and decrease of ODC and AHH activities, compared to control, DMBA, and DMBA + 12-O-tetradecanoylphorbol 13-acetate treated cultures.

Effect of nutritional status on mutagenicity of urine excreted by rats treated with standard/experimental carcinogens.

Urine samples, collected from Sprague Dawley rats treated with extracts of tobacco/masheri, benzo (a) pyrene, N'-nitrosonornicotine, N'-nitrosodiethylamine and maintained on semi-synthetic diets sufficient or deficient in Vitamin A, B and protein were tested for mutagenicity using Salmonella/microsome assay. The mutagenic activity of urine or various treated groups was in the order deficient diet greater than standard laboratory diet greater than nutritionally sufficient diet. Present results confirmed the earlier observations that nutritionally deficient animals are likely to have more exposure to mutagenic metabolites that are generated by increased phase I enzymes and decreased detoxification system.

Chemical analysis of smoke of Indian cigarettes, bidis and other indigenous forms of smoking--levels of steam-volatile phenol, hydrogen cyanide and benzo(a)pyrene.

Levels of steam-volatile phenol, hydrogen cyanide and benzo(a)pyrene in various types of tobacco smoking products marketed in the country have been determined for the first time. Steam-volatile phenol levels in six popular brands of Indian cigarettes varied from 118 to 226 micrograms, and in six popular brands of bidis, from 129 to 273 micrograms. Cheroot and cigarillos yielded 400 micrograms and 333 micrograms steam-volatile phenol respectively. The hydrogen cyanide levels in the mainstream smoke of five popular brands of Indian cigarettes varied from 366 to 638 micrograms and in the mainstream smoke of four popular brands of bidis from 688 to 904 micrograms. Cheroot and cigarillos yielded 588 micrograms and 1119 micrograms hydrogen cyanide respectively. The values of benzo(a)pyrene content in Indian cigarettes varied from 85 to 114 ng and in bidis from 108 to 144 ng. Herbal bidi and cheroot had 1315 ng and 2519 ng benzo(a)pyrene respectively. Cigarettes were smoked as per international standard smoking conditions and the levels of noxious agent were found to be higher than in currently marketed western cigarettes. However, these levels in all the indigenous products including bidis cannot be directly compared with those of cigarettes as they were smoked under modified conditions.

Total particulate matter and nicotine in Indian bidis and cigarettes: a comparative study of standard machine estimates and exposure levels in smokers in Bombay.

Standard emission levels of total particulate matter (TPM) and nicotine in bidi and cigarette smoke were compared with exposure levels based on smoking behaviour of smokers in Bombay. Bombay cigarette smokers are getting much higher amount of carcinogenic dry TPM (28 to 79%) and nicotine (31 to 104%), compared to standard machine estimates. In the case of regular bidi (60 mm) harmful ingredients like dry TPM decreased from 11 to 15 percent and nicotine increased from 11 to 22 percent, whereas long bidi (80 mm) delivered higher amount of dry TPM (14 to 22%) and nicotine (33 to 37%) in smokers in Bombay compared to standard machine estimates.

Sequential analysis of experimental oral carcinogenesis in hamster cheek pouch using 9,10-dimethyl-1-2-benzanthracene.

The utility of hamster cheek pouch model for studies on oral carcinogenesis has been explored using 9,10-dimethyl-1-2-benzanthracene as a carcinogen. Based on the morphological, histopathological and electron microscopic observations the hamster cheek pouch carcinogenesis can be separated into different stages starting from the normal to the fully grown carcinomas. This system is reliable, precise, consistent and can be used for the evaluation of different agents for initiating or promoting effects and as well as for the studies on mechanism of oral carcinogenesis.