Effect of Post Material and Length on Fracture Resistance of Endodontically Treated Premolars: An In-Vitro Study.

BACKGROUND: Endodontically treated teeth with posts are more prone to fracture. Hence, the purpose of this study was to investigate the in-vitro fracture resistance of devitalized teeth and mode of failure restored with posts of different materials and different lengths. MATERIALS AND METHODS: Sixty freshly extracted human mandibular premolars were endodontically treated and then restored with 1 of 2 prefabricated posts: Stainless-steel (SS) and glass-fiber (fiber posts [FP]) with intraradicular lengths of 4, 5 or 10 mm (n = 10). Following core restoration, a static compressive load was applied perpendicular to the long-axis of the teeth. Initial failure of each specimen was recorded in Newton. The mode of failure was also determined radiographically. The data were analyzed using two-way ANOVA and Tukey's post-hoc analysis with Bonferroni adjustment. RESULTS: Analysis indicated significant differences (P < 0.001) among the groups. Among the SS posts, SS/7 (246 N) exhibited the highest failure load and SS/4 (122 N) the lowest. FP/10 (140.5 N) exhibited the highest failure load among the FP and FP/4 (68.5 N) the lowest. SS posts showed post pull out, followed by core fracture while FP showed core debonding, followed by core fracture as the primary mode of failure. CONCLUSION: Fracture resistance of the teeth proportionately increased with increase in the length of FP while it decreased with that of metal post. SS posts showed greater fracture resistance than FP when 90° load was applied.

Comparative Evaluation of Push Out Bond Strength of a Fiber Post System using Four Different Resin Cements: An In-Vitro Study.

BACKGROUND: Debonding is one of the frequent causes of failure experienced in fiber-reinforced composite posts, and establish along post space-dentin adhesive interface. The purpose of this study was to assess push-out bond strength of a fiber-reinforced post system using four different resin cements. MATERIALS AND METHODS: In this in-vitro study 40 mandibular premolars were decoronated, and roots were treated endodontically. Following the post space preparation, the roots were grouped into four groups of 10 specimens each. Fiber-reinforced composite posts were cemented with four resin cement systems: (a) Multilink Speed, (b) Rely X Unicem, (c) Calibra, and (d) Permaflo DC. Three sections of each root, with a thickness of 3 mm, were prepared. The push-out test was with a universal testing machine at a crosshead speed of 1 mm/min, and bond strength values were evaluated. The data were analyzed with using multivariate analysis of variance (MANOVA) and post-hoc Scheffe test. RESULT: The mean push-out bond strength was highest for Rely X Unicem (18.0 ± 1.81), followed by Multilink Speed (13.1 ± 0.75) and Permaflo DC (12.8 ± 0.95). The lowest mean push-out bond strength was seen with Calibra (11.8 ± 0.69). There were statistically significant differences seen in the push-out bond strength of resin cement in different root canal regions using MANOVA and post-hoc Scheffe test. CONCLUSION: Mean push-out bond strength was highest for Rely X Unicem, followed by Multilink Speed and Permaflo DC. Lowest mean push-out bond strength was seen with respect to Calibra.

New anesthetic technique in periodontal procedures.

Periodontal procedures require injection of local anesthetic solution to avoid patient discomfort. Multiple injections are required to anesthetize the anterior maxilla in the region of the premolars to incisors. Anterior middle superior alveolar nerve block is a single palatal injection technique, which anesthetizes the facial and palatal gingiva as well as pulp in the region of the maxillary central incisors to the premolars without any collateral facial anesthesia. This case series presents the application of the anterior middle superior alveolar nerve block in periodontal therapy.

Synthesis and characterization of lanthanide(III) complexes with a mesogenic Schiff-base, N,N'-di-(4-decyloxysalicylidene)-2',6'-diaminopyridine.

A mesogenic Schiff-base, N,N'-di-(4-decyloxysalicylidene)-2',6'-diaminopyridine, H2ddsdp (abbreviated as H2L3) that exhibits nematic mesophase, was synthesized and its structure studied by elemental analysis, mass spectrometry, NMR & IR spectral techniques. The Schiff-base, H2L3, upon condensation with hydrated lanthanide(III) nitrates, yields LnIII complexes of the general composition [Ln2(L3H2)3(NO3)4](NO3)2, where Ln=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy and Ho. Among the metal complexes, only that of HoIII is found to be mesogenic with smectic-X and nematic phases. The IR and NMR spectral data imply a bi-dentate bonding of the Schiff-base in its zwitterionic form (as L3H2) to the LnIII ions through two phenolate oxygens, rendering the overall geometry of the complexes to seven-coordinated polyhedron, possibly distorted mono-capped octahedron.

Homo dinuclear lanthanide(III) complexes of a mesogenic Schiff-base, N,N'-di-(4-decyloxysalicylidene)-1',6'-diaminohexane: synthesis and characterization.

A mesogenic Schiff-base, N,N'-di-(4-decyloxysalicylidene)-1',6'-diaminohexane, H2ddsdh (abbreviated as H2L2) that exhibits smectic-B (SmB) mesophase, was synthesized and its structure studied by elemental analysis, mass spectrometry, NMR & IR spectral techniques. The Schiff-base, H2L2, upon condensation with hydrated lanthanide(III) nitrates, yields LnIII complexes of the general composition [Ln2(L2H2)3(NO3)4](NO3)2, where Ln=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy and Ho. IR and NMR spectral data imply a bi-dentate bonding of the Schiff-base in its zwitterionic form (as L2H2) to the LnIII ions through two phenolate oxygens. The POM and DSC studies reveal that none of the LnIII complexes exhibits mesomorphism. Fluorescence studies show that the TbIII complex displays characteristic metal-centered fluorescence (solution state).

Evaluation of amlodipine, lisinopril, and a combination in the treatment of essential hypertension.

Angiotensin converting enzyme (ACE) inhibitors and dihydropyridine calcium antagonists are well established and widely used as monotherapy in patients with mild to moderate essential hypertension. Earlier studies combining short acting drugs from these classes require multiple dosing and were associated with poor compliance. Availability of longer acting compounds allows once daily administration to avoid the inconvenience of a multiple daily dose. It was decided to perform a randomised double blind, crossover study with the long acting calcium channel blocker amlodipine and the long acting ACE inhibitor lisinopril, given either alone or in combination in essential hypertension. Twenty four patients with diastolic blood pressure (DBP) between 95 and 104 mm Hg received amlodipine 2.5 mg and 5 mg, lisinopril 5 mg and 10 mg, and their combination as per a prior randomisation schedule. Supine and standing blood pressure and heart rate were recorded at weekly intervals. Higher doses of both the drugs individually or in combination were used if the target supine DBP below 90 mm Hg was not achieved. There was a significant additional blood pressure lowering effect with the combination when compared either with amlodipine or lisinopril alone. Five mg amlodipine and 10 mg lisinopril monotherapy achieved the target blood pressure in 71% and 72% patients respectively. The combination of 2.5 mg amlodipine with 5 mg lisinopril produced a much more significant lowering of blood pressure in a higher percentage of patients than that with an individual low dose.

Isolation and characterization of allergens from the seeds of Vigna sinensis.

Allergenic components of cowpea vegetable green seeds (Vigna sinensis) were isolated based on solubility, isoelectric precipitation and molecular mass. The allergenicity of the cowpea fractions was monitored by enzyme-linked immunosorbent assay (ELISA) and skin-prick test. The allergenic albumin fraction was characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and IgE-specific immunoblotting. The 41 and 55 kDa protein components were found to be major allergens and the allergenicity was resistant to heat and proteolytic enzyme digestion. This study confirms the presence of potent allergens in cowpea seeds.

Identification of risk factors for specific subsites within the oral and oropharyngeal region--a study of 647 cancer patients.

Studies on site specific risks for oral cancers are few. Present investigation explores the possible role of human sociodemographic factors in causing oral cancer. Majority of patients had poor oral hygiene (85.5%) and belonged to 51-60 years age group (35.7%). Most of the subjects were agriculture workers (30.3%). Tongue and floor of mouth included majority of the affected sites (77.2%). Male to female ratio was highest for tonsil (32.3%) but differed marginally for other subsites. Majority of females used tobacco (81%) while males users of tobacco, alcohol and smoking reported in nearly equal proportions. Tobacco and smoking were found as primary risk factors for several intraoral subsites. However, for tongue, palate and lip no risk factor could be identified from given patients' characteristics. In general, tobacco posed high risk for buccal mucosa and alveolus in comparison to other subsites. Smoking affected tonsil and floor of mouth more than other sites. Alcohol posed more risk for buccal mucosa and floor of mouth than tongue.

Determination of terazosin in human plasma, using high-performance liquid chromatography with fluorescence detection.

A selective, sensitive, rapid and reproducible high-performance liquid chromatographic method for the determination of terazosin in plasma is described. The structurally related compound prazosin was used as an internal standard. The method comprises extraction with methylene chloride followed by chromatography on a C18 reversed-phase column. The compounds were detected using spectrofluorimetry. The absolute recoveries were more than 90% with a minimal detection of 1 ng/ml and calibration curve was linear between 1 and 80 ng/ml.

Rapid and selective analysis of secnidazole in human plasma using high-performance liquid chromatography with ultraviolet detection.

A rapid, reproducible high-performance liquid chromatographic method for the determination of secnidazole, 5-nitroimidazole class of antiprotozoals from blood is described. Metronidazole was used as an internal standard. A simple extraction step with dichloromethane was done before chromatography on a C18 column with the wavelength fixed at 276 nm on the UV detector. Blood levels up to 500 ng/ml have been measured with good precision in the healthy volunteers after 1 g of secnidazole was administered. The present described method can readily be utilized for routine pharmacokinetic studies.

An evaluation of antidepressants in rheumatic pain conditions.

In a randomized, double-blind, parallel study, fluoxetine and amitriptyline were compared with placebo in the treatment of chronic rheumatic pain. A total of 59 patients were evaluated during 4 wk of treatment and received 20 mg fluoxetine, 25 mg amitriptyline, or placebo daily. Pain intensity, pain relief, vital variables, and global evaluation were used to assess efficacy. To evaluate safety variables, the incidence of side effects was noted. Both amitriptyline and fluoxetine significantly reduced pain intensity compared with placebo. Similarly, pain relief was greater with both amitriptyline and fluoxetine than with placebo. At the end of the fourth week, fluoxetine was superior in efficacy to amitriptyline. The incidence of adverse effects was significantly greater with amitriptyline; dryness of the mouth was the most predominant side effect. We conclude that fluoxetine is an effective analgesic with fewer side effects.

Significance of lymphocytic sister chromatid exchange frequencies in ovarian cancer patients.

Very few studies report the analysis of sister chromatid exchanges in ovarian cancer patients. We tested the null hypothesis that SCE frequency increases with the advancing stages of ovarian cancer and follows a Poisson distribution. As controls we examined age- and sex-matched healthy volunteers who had no such past history. An increased average SCE frequency was observed in ovarian cancer patients (6.34 +/- 0.09) vis-à-vis controls (4.47 +/- 0.12). Further, the data also suggested a stage-wise increase in the SCE frequency.

A rapid silver staining and destaining technique for the nucleolus organizer region.

Silver staining of nucleolar organizing regions (NOR) is common, but a standard protocol is lacking. A modification of a rapid silver nitrate staining technique for NORs is presented here. Advantages of the modified technique include reliability, speed, cost and the fact that it can be carried out in the light.

Multicentric, placebo-controlled, randomised double-blind evaluation of a new herbal cream in vagial infections.

Efficacyand safety of a new herbal cream containing aqueous extracts of Azadirachta indica, Curcuma longa, Pongamia glabra, Glycyrrihiza glabra and Santallum album were evaluated in amulticentric, randomized, double-blind, placebo-controlled study. With active drug treatment, there was significant improvement in various signs like redness, oedema and symptoms like itching, burning, discharge and discomfort, compared to placebo treatment. Microscopic examination of smear and culture showed significant reduction of offending organisms after treatment with active drug. In patient's global evaluation, active drug was rated 70% as very good and in investigators evaluation 82% as very effective and effective. The overall efficacy was as high as 76% with active drug as against only 24% with placebo. Both active drug and placebo were well tolerated.

Spatio-temporal expression of estrogen sulfotransferase within the hepatic lobule of male rats: implication of in situ estrogen inactivation in androgen action.

Estrogen sulfotransferase (EST) catalyzes transfer of the sulfate group from phosphoadenosine phosphosulfate to estrogenic steroids. Since estrogen sulfates do not bind to the estrogen receptor with high affinity, EST can control the intracellular level of the receptor-active estrogens. Androgen action in the rat liver, as indicated by the androgenic induction of alpha 2u-globulin, is inhibited by low levels of estrogens. Thus, in situ estrogen inactivation by EST is expected to increase hepatic androgen sensitivity. During the lifespan of the animal, rat liver undergoes three distinct phases of androgen sensitivity, i.e. prepubertal androgen insensitivity, androgen sensitivity after approximately 40 days of age, and androgen insensitivity during senescence (greater than 750 days). EST in the liver is expressed only after puberty, when the liver becomes androgen sensitive. Furthermore, localization of EST and its corresponding mRNA within the lobular unit of the liver demonstrates that only androgen-responsive hepatocytes located around the central vein contain immunoreactive EST and its corresponding mRNA. These temporal and spatial correlations of EST expression and hepatic androgen sensitivity support the concept that steroid-inactivating enzymes play important roles in sex hormone action.

Estrogen sulfotransferase of the rat liver: complementary DNA cloning and age- and sex-specific regulation of messenger RNA.

Mammalian estrogen sulfotransferase (EST; EC 2.8.2.4) sulfurylates the hydroxyl group of estrogenic steroids by transferring the sulfate from a cosubstrate adenosine 3'-phosphate-5'-phosphosulfate. Sulfurylated steroids do not bind to the estrogen receptor with high affinity and, therefore, are hormonally inactive. We have purified rat liver EST and developed monoclonal antibody to this enzyme. By immunoscreening a lambda gt-11 expression library constructed from male rat liver cDNAs, the cDNA clone corresponding to EST was identified and isolated. A recombinant expression plasmid (pCMV5) containing this cDNA insert when transfected into COS-7 cells generated both immunologically and enzymatically active EST. With the help of this cDNA probe, we have explored the regulation of the EST mRNA in the liver and the possible role of this enzyme in sex hormone action. During the lifespan of male rats, only the young adult animals show hepatic androgen responsiveness. Also, estrogenic hormones strongly antagonize androgen action in the rat liver. Northern blot analysis of liver RNA derived from male rats of different ages shows that the androgen sensitivity of young adult animals is associated with a high expression of EST mRNA. During the same period, mRNA corresponding to dehydroepiandrosterone sulfotransferase is markedly (approximately 10-fold) down-regulated. Such a correlation is in concordance with the role of these enzymes in the maintenance of hepatic androgen sensitivity during young adult life by inactivating the estrogenic and sparing the androgenic steroids. Furthermore, the increase in the hepatic androgen sensitivity of androgen-treated female rats is also associated with the induction of EST.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparative study on the periodontal health status of adult populations of Kenya and India.

The purpose of this study was to compare the oral hygiene and periodontal health status of 497 randomly selected Kenyan and Indian adult populations aged between 20 and 35 years. Oral hygiene and periodontal health status were assessed using Silness and Loe plaque Index and Russel's Periodontal Index respectively. Results revealed that the overall mean plaque and periodontal index scores of Kenyan participants were significantly lower than those of Indians. Increase of mean Periodontal index with age was found to be significant among Kenyan participants and insignificant among Indian participants Kenyan female participants were found to have significant lower mean plaque and periodontal index scores than males. However, the mean periodontal index score of Indian male participants was found to be lower than that of female participants. It is concluded that Kenyan participants had better periodontal and oral hygiene status than Indian participants and that Indian females unlike Kenyan females had poorer periodontal health status than male.

Immediately preovulatory levels of messenger ribonucleic acid for inhibin alpha-subunit are diminished in granulosa cells from successful in-vitro fertilization-embryo transfer.

Inhibin, a gonadal glycoprotein which suppresses pituitary gonadotrophin secretion, preferentially follicle stimulating hormone, has been extensively characterized. It consists of two covalently bound subunits, the alpha- and beta-subunits, encoded by separate genes. In this study, the expression of messenger ribonucleic acid (mRNA) for the inhibin alpha-subunit was studied by Northern blot analysis in granulosa cells of women undergoing in-vitro fertilization/embryo transfer (IVF/ET). Three patient groups were studied: women who failed to become pregnant (n = 11), women who became pregnant but experienced early spontaneous abortion (n = 3) and women who conceived normal ongoing pregnancies (n = 4). Granulosa cells were obtained at the time of follicle aspiration. Levels of alpha-subunit mRNA were 40% lower in patients establishing normal pregnancies than in those who failed to become pregnant or who spontaneously aborted. Thus, a relative diminution of immediately preovulatory levels of mRNA for inhibin alpha-subunit is a marker of success in clinical IVF/ET cycles. This marker of IVF/ET success can be related to previously established markers of success (increased follicular fluid oestradiol and decreased follicular fluid cyclic adenosine monophosphate) by known physiological mechanisms.

Androgen receptor messenger ribonucleic acid (mRNA) in the rat liver: changes in mRNA levels during maturation, aging, and calorie restriction.

By means of RNAase protection assay with an antisense cRNA probe, we have shown that the liver of the young adult male rat contains androgen receptor (AR) mRNA to a level of 4% compared to the prostate. Steady state levels of AR mRNA in the liver show both sex and age specificity. Compared to that of the male, the female liver contains a markedly reduced amount of AR mRNA. AR mRNA is almost undetectable in livers of prepubertal male (less than 35 days old) and senescent male (greater than 750 days old) rats. Both prepubertal and senescent animals are relatively insensitive to the androgenic induction of alpha 2u-globulin, a hepatic secretory protein. The age-dependent decline in hepatic androgen sensitivity and AR mRNA level can be delayed considerably by a 40% reduction in the dietary calorie intake. Analysis of poly(A)-containing RNA from two liver cell populations, hepatocytes and nonhepatocytes, revealed that only the hepatocytes that express alpha 2u-globulin gene contain AR mRNA. From these results and our earlier observation of in vitro induction of alpha 2u-globulin in isolated rat liver, we conclude 1) that androgen can act directly on hepatocytes to promote alpha 2u-globulin synthesis; 2) that changes in the hepatic androgen sensitivity during maturation and aging are reflections of the age-dependent expression of the receptor gene; and 3) that retardation of the age-dependent loss of androgen sensitivity by calorie restriction is due to a concomitant delay in the decline of the hepatic AR mRNA level.

Characterization of Int-5, a locus associated with early events in mammary carcinogenesis.

Three chemically-induced precancerous mammary hyperplasias, independently isolated in BALB/c mice, all contained mouse mammary tumor virus (MMTV) proviral DNA integrated into a common region in chromosomal DNA, designated Int-5 (Formerly Int-H, Gray et al., 1986). This site was cloned from a hyperplastic outgrowth (D2) into lambda phage. A 1.7 Kb Hind III DNA fragment, which flanks the 5' end of the MMTV insert, was generated from the cloned Int-5 region. This fragment was used as probe (IH-2) to localize Int-5 to mouse chromosome 9. The IH-2 sequence was highly conserved in DNA of several mammalian species including man, in three other widely divergent vertebrate phyla, and in C. elegans. The Int-5 region, containing 5.6 Kb 5' and 12.8 Kb 3' to the MMTV integration site in D2, was cloned in EMBL-3 from a BALB/c genomic DNA library. cDNA complementary to poly A+ lactating mammary gland RNA, annealed with Sst-1 fragments spanning most of the BALB/c Int-5 clone. The highest level of Int-5 specific poly A+ mRNA was detected in D2 tumor. Lactating mammary gland and D2 hyperplastic alveolar nodule contained 5-fold less Int-5 RNA while liver contained 8-fold less Int-5 RNA. Int-5 cDNA (IH-3) annealed with two RNA species of approximately 3.3 and 4.0 Kb. These data are consistent with the hypothesis that Int-5 contains an oncogene, different from any other previously described, involved in early events in some models of chemical carcinogenesis.