Search PubMed⌕ Search

Biomedical subjects

B Nair

Publications and source records attributed to B Nair.

At least 19 recordsLinked to original sources
PubMed2002

Early versus deferred androgen suppression in the treatment of advanced prostatic cancer.

BACKGROUND: Prostate cancer is a leading cause of cancer death in men. Treatment goals for men with advanced prostate cancer include prolonging survival, preventing or delaying symptoms due to disease progression, improving and maintaining quality of life, reducing treatment related morbidity. Androgen suppression therapy is considered a mainstay of treatment for men with advanced prostate cancer. However it is not clear whether early androgen suppression for men with locally advanced disease or asymptomatic metastases improves length and quality of life compared to androgen suppression deferred until signs and symptoms of clinical progression. OBJECTIVES: This systematic review assessed the efficacy and adverse effects of primary therapy with early versus deferred androgen suppression therapy in men with advanced prostate cancer. SEARCH STRATEGY: Randomized controlled trials were searched in general and specialized databases (MEDLINE, EMBASE, CancerLIT, Cochrane Library, VA Cochrane Prostate Disease register) and by reviewing bibliographies including those of the Blue Cross and Blue Shield Association Technology Evaluation Center/Evidence-based Practice Center of the Agency for Healthcare Research and Quality (BCBS/TEC-AHRQ) report No.4. SELECTION CRITERIA: All published randomized trials were eligible for inclusion provided they: randomized men with advanced prostate cancer to early versus deferred androgen suppression; reported overall, progression-free, and cancer-specific survival, and/or adverse events; did not utilize androgen suppression as adjuvant therapy to radiation treatment. DATA COLLECTION AND ANALYSIS: An independent reviewer using a standardized form extracted information on trial characteristics, interventions, and outcomes. Results were reviewed for accuracy and discrepancies resolved by discussion. The main outcome measure for comparing effectiveness was the overall survival at 1, 2, 5 and 10 years. Progression-free survival, cancer-specific survival, complications due to disease progression and the incidence of adverse effects of treatment were also measured. MAIN RESULTS: Four trials involving 2,167 patients were included in this review. All of the trials were conducted prior to use of prostate specific antigen (PSA) testing. There was variability between studies regarding the treatments used and the requirements for initiation of treatments. The percent overall survival at 1, 2, 5, and 10 years for the early treatment group was 88%, 73%, 44%, and 18%. For the deferred therapy group the percent overall survival was 86%, 71%, 37%, and 12%. The pooled estimate for the difference in overall survival favored early therapy but was significant only at 10 years when few patients had survived [OR = 1.16 (95% CI: 0.90 to 1.49) at 1 year, 1.08 (95% CI: 0.89 to 1.33) at 2 years, 1.19 (95% CI: 0.95 to 1.50) at 5 years, and 1.50 (95% CI: 1.04 to 2.16) at 10 years]. The pooled estimate of prostate cancer specific survival at 2, 5, and 10 years favored early therapy though the confidence intervals were wide and the results not statistically different. The risk differences at 2, 5, and 10 years were 2.7%, 5.8%, and 4.6%. Although each study used unique definitions of progression free survival, all studies found progression free survival was consistently better in the early intervention group at all time points. Complications due to disease progression were only reported in one study but were more frequent in the deferred treatment group. Adverse events due to treatment were also only reported in one study but occurred more frequently in the early treatment group. REVIEWER'S CONCLUSIONS: The evidence from randomized controlled trials is limited by the variability in study design, stage of cancer and subjects enrolled, interventions utilized, definitions and reporting of outcomes and the lack of PSA testing for diagnostic and monitoring purposes. However, the available information suggests that early androgen suppression for treatment of advanced prostate cancer reduces disease progression and complications due to progression. Early androgen suppression may provide a small but statistically significant improvement in overall survival at 10 years. There was no statistically significant difference in prostate cancer specific survival but a clinically important difference could not be excluded. These outcomes need to be evaluated with the evidence suggesting higher costs and more frequent treatment related adverse effects with early therapy. Additional studies are required to evaluate more definitively the efficacy and adverse effects of early versus delayed androgen suppression in men with prostate cancer. In particular trials should evaluate patients with advanced prostate cancer diagnosed by PSA testing and men with persistent or rising PSA levels following treatment options (e.g. radical prostatectomy, radiation therapy or observation) for clinically localized disease.

Androgen Antagonists↗
PubMed2001

Final report on the safety assessment of Benzyl Alcohol, Benzoic Acid, and Sodium Benzoate.

Benzyl Alcohol is an aromatic alcohol used in a wide variety of cosmetic formulations as a fragrance component, preservative, solvent, and viscosity-decreasing agent. Benzoic Acid is an aromatic acid used in a wide variety of cosmetics as a pH adjuster and preservative. Sodium Benzoate is the sodium salt of Benzoic Acid used as a preservative, also in a wide range of cosmetic product types. Benzyl Alcohol is metabolized to Benzoic Acid, which reacts with glycine and excreted as hippuric acid in the human body. Acceptable daily intakes were established by the World Health Organization at 5 mg/kg for Benzyl Alcohol, Benzoic Acid, and Sodium Benzoate. Benzoic Acid and Sodium Benzoate are generally recognized as safe in foods according to the U.S. Food and Drug Administration. No adverse effects of Benzyl Alcohol were seen in chronic exposure animal studies using rats and mice. Effects of Benzoic Acid and Sodium Benzoate in chronic exposure animal studies were limited to reduced feed intake and reduced growth. Some differences between control and Benzyl Alcohol-treated populations were noted in one reproductive toxicity study using mice, but these were limited to lower maternal body weights and decreased mean litter weights. Another study also noted that fetal weight was decreased compared to controls, but a third study showed no differences between control and Benzyl Alcohol-treated groups. Benzoic Acid was associated with an increased number of resorptions and malformations in hamsters, but there were no reproductive or developmental toxicty findings in studies using mice and rats exposed to Sodium Benzoate, and, likewise, Benzoic Acid was negative in two rat studies. Genotoxicity tests for these ingredients were mostly negative, but there were some assays that were positive. Carcinogenicity studies, however, were negative. Clinical data indicated that these ingredients can produce nonimmunologic contact urticaria and nonimmunologic immediate contact reactions, characterized by the appearance of wheals, erythema, and pruritus. In one study, 5% Benzyl Alcohol elicited a reaction, and in another study, 2% Benzoic Acid did likewise. Benzyl Alcohol, however, was not a sensitizer at 10%, nor was Benzoic Acid a sensitizer at 2%. Recognizing that the nonimmunologic reactions are strictly cutaneous, likely involving a cholinergic mechanism, it was concluded that these ingredients could be used safely at concentrations up to 5%, but that manufacturers should consider the nonimmunologic phenomena when using these ingredients in cosmetic formulations designed for infants and children. Additionally, Benzyl Alcohol was considered safe up to 10% for use in hair dyes. The limited body exposure, the duration of use, and the frequency of use were considered in concluding that the nonimmunologic reactions would not be a concern. Because of the wide variety of product types in which these ingredients may be used, it is likely that inhalation may be a route of exposure. The available safety tests are not considered sufficient to support the safety of these ingredients in formulations where inhalation is a route of exposure. Inhalation toxicity data are needed to complete the safety assessment of these ingredients where inhalation can occur.

Animals↗
PubMed2001

Final report on the safety assessment of Mentha Piperita (Peppermint) Oil, Mentha Piperita (Peppermint) Leaf Extract, Mentha Piperita (Peppermint) Leaf, and Mentha Piperita (Peppermint) Leaf Water.

Mentha Piperita (Peppermint) Oil, Mentha Piperita (Peppermint) Leaf Extract, Mentha Piperita (Peppermint) Leaf, Mentha Piperita (Peppermint) Leaf Water are obtained from the Mentha piperita plant. The oil is currently used in cosmetic formulations as a fragrance component, but previously had been also described as a denaturant. The extract and leaves are described as biological additives, but only the extract is reported to be used. Peppermint Water is described as a flavoring agent or fragrance component, but is not currently in use. Peppermint Oil is used at a concentration of < or = 3% in rinse-off formulations and < or = 0.2% in leave-on formulations. Peppermint Oil is composed primarily of menthol and menthone. Other possible constituents include pulegone, menthofuran, and limone. Most of the safety test data concern Peppermint Oil. The oil is considered to present the "worst case scenario" because of its many constituents, so data on the oil were considered relevant to the entire group of ingredients. Peppermint Oil was minimally toxic in acute oral studies. Short-term and sub-chronic oral studies reported cystlike lesions in the cerebellum in rats that were given doses of Peppermint Oil containing pulegone, pulegone alone, or large amounts (>200 mg/kg/day) of menthone. Pulegone is also a recognized hepatotoxin. Repeated intradermal dosing with Peppermint Oil produced moderate and severe reactions in rabbits, although Peppermint Oil did not appear to be phototoxic. Peppermint Oil was negative in the Ames test and a mouse lymphoma mutagenesis assay but gave equivocal results in a Chinese hamster fibroblast cell chromosome aberration assay. In a carcinogenicity study of toothpaste and its components, no apparent differences were noted between mice treated with Peppermint Oil and those treated with the toothpaste base. Isolated clinical cases of irritation and/or sensitization to Peppermint Oil and/or its constituents have been reported, but Peppermint Oil (8%) was not a sensitizer when tested using a maximization protocol. It was expected that dermal absorption of Peppermint Oil would be rapid, following that of menthol, a major component, but in no case would be greater than absorption through the gastrointestinal tract. Because of the toxicity of pulegone, the safe concentration of this constituent was limited to < or = 1%. This concentration was achievable both by controlling the time of harvest and processing technique. There is evidence that menthol can enhance penetration of other agents. Formulators were cautioned that this enhanced penetration can affect the use of other ingredients whose safety assessment was based on their lack of absorption. With the limitation that the concentration of pulegone in these ingredients should not exceed 1%, it was concluded that Mentha Piperita (Peppermint) Oil, Mentha Piperita (Peppermint) Extract, Mentha Piperita (Peppermint) Leaves, Mentha Piperita (Peppermint) Water are safe as used in cosmetic formulations.

Animals↗
PubMed2000

Advance care planning in residential care.

BACKGROUND: To provide optimal care for our ageing population, some form of advance care planning (ACP) is essential. Overseas data suggest that the process of ACP and the use of advance care directives (ACD) is suboptimal in residential care institutions. By comparison there are few Australian data. AIM: To study the process of ACP and the prevalence of ACD in residential care. METHODS: Cross-sectional study using a questionnaire in the Hunter area, NSW, Australia. RESULTS: Very low levels of formal advance directives were found (available for only 0.2%). Only 1.1% of residents had 'no-CPR' orders documented in the medical record, while 5.6% had a formal guardian and 2.8% had an enduring guardian. Informal processes of advance planning were much more prevalent. Sixty-five per cent had a 'person responsible' recorded to make decisions for them while in 13% of cases, there was 'staff consensus' as to the optimal care for the patient. However, in 10.6% there was no clear process for medical decision making identified. CONCLUSIONS: Advanced directives are infrequently used in residential care. Further qualitative and quantitative studies are warranted to explore current processes of decision making.

Advance Directives↗
PubMed1997

Expression of epidermal growth factor receptor in gestational trophoblastic diseases.

Gestational trophoblastic disease is an abnormal condition of the placenta, the incidence of which is very high in the State of Kerala, India. The biology of this disease is vague and methods to determine the malignant potential are limited. Placentae of normal (50) and molar pregnancies (95), including 32 showing persistent disease, were used for the study. Epidermal growth factor (EGFR), expression was evaluated by immunohistochemistry using monoclonal antibody, and quantified using the 125I-EGF-binding assay. EGFR was expressed more strongly in molar placentae than in normal placentae of similar gestational age, and was strong in the molar placentae of all gestational ages, whereas expression was mainly restricted to the first and second trimesters in normal placentae. Moles with early presenting symptoms (before 16 weeks) were at a higher risk of developing persistent disease. To conclude, the immunohistochemical study shows high expression of EGFR in early normal placentae and in moles, linking its role to the proliferative and differentiating activity of trophoblasts. Tumours with a histological diagnosis of invasive moles and choriocarcinoma showed very strong binding of EGFR. The present observations also suggest the possibility of mutated EGF receptors being present in persistent trophoblastic disease.

Adult↗
PubMed1997

Gender differences and other determinants of the rise in plasma homocysteine after L-methionine loading.

The methionine load test is widely used to identify subjects with mild homocysteinemia. We studied factors influencing the rise in plasma homocysteine (tHcy) levels following oral methionine loading, after taking into account determinants of the basal level. The study population comprised 522 persons (mean age 53, range 17 to 95; 63% male; 60% with coronary disease). tHcy was measured fasting and 4 h after administration of L-methionine (dose 4 g/m2). The percentage rise in tHcy was greater in females, at younger ages, and with lower serum creatinine. Basal tHcy was lower in those with high levels of serum folate, red cell folate and serum B12; they also showed a greater percentage rise with loading. After adjustment for age, creatinine and serum vitamins the percent rise was greater in females (mean 230%, S.D. 92) than in males (mean 172%, S.D. 71, P < 0.0001). About 1/4 of this effect was explained by the methionine dose, but important independent gender effects remained. When the results of the loading test were compared with an overall reference range, females were systematically labelled as 'high' but comparison with age and gender-specific reference ranges normalised the sex distribution. Our data show that a single L-methionine loading protocol for both sexes is not appropriate. Gender-specific reference ranges should be used to define post-load homocysteinemia and previous studies which have identified a high proportion of females with this trait probably reflect the need for gender specific reference ranges.

Adolescent↗
PubMed1997

Fasting and post-methionine homocyst(e)ine levels in a healthy Australian population.

BACKGROUND: Plasma homocyst(e)ine (H[e]) is frequently measured in patients with occlusive vascular disease, but levels vary between populations and between laboratories. AIMS: We sought to derive reference values for an Australian population over a wide age range. METHODS: We measured plasma H(e) in the fasting state and after methionine loading in 116 volunteers selected at random from the Hunter districts of the New South Wales electoral roll and in 49 apparently healthy, active subjects recruited from the region's lawn bowling clubs. Reference ranges were derived for both sexes, in three age strata. We collaborated with two international laboratories in standardising our results. RESULTS: Mean fasting H(e) levels were approximately 2.7 mumol/L higher in men than women, at all ages (95% CI for the difference, 1.2 to 4.1 mumol/L). Levels increased with age (approximately 1.0 mumol/L/decade, 95% CI 0.5 to 1.5) and were correlated with serum creatine (r = 0.48), serum folate (r = -0.30), red cell folate (r = -0.25) and serum B12 (r = -0.31) (all p < 0.001). These results are similar to those reported in other populations. CONCLUSIONS: We have defined reference ranges for a typical Australian population, following careful laboratory standardisation. H(e) levels must be interpreted with regard to age, sex, renal function and vitamin B12 and folate status.

Adult↗
PubMed1997

Use of patient restraints in four Australian teaching hospitals.

To examine the patterns of use of patient restraints in Australian hospitals and the level of adherence to accepted guidelines, we undertook a point-prevalence study in four teaching hospitals in three different States. This involved ward inspections and review of case notes. Overall, 51 (12.5%) of the 408 people audited were being restrained with a variety of physical and chemical agents. The rate of restraint use varied from 8.5% to 18.5% between hospitals. Although the overall prevalence of restraint use increased with age, the hospital with the oldest patients used restraints least. At all hospitals, there was scant documentation in the case notes concerning the use of restraints. The prevalence of restraint use varies widely in different hospitals. As this is not explained by the patient profile, it probably reflects different philosophies of care. Documentation of the use of restraints needs to be improved in all the centres studied.

Adolescent↗
PubMed1996

Cardiovascular findings in self-reported healthy elderly. The Elite Seniors Study.

BACKGROUND: A descriptive study of self-reported healthy elderly in Newcastle was undertaken for an adequate understanding of the normal characteristics of the elderly. AIMS: We sought to determine the frequency of abnormal clinical, laboratory and echocardiographic findings in a self-reported healthy elderly population. METHODS: Volunteers aged greater than 75 years were recruited from active members of the region's bowling clubs. Forty-five subjects with no self-reported vascular or cardiac disease underwent clinical, laboratory and echocardiography assessment. RESULTS: Minor cardiovascular abnormalities were frequently detected. Echocardiography correspondingly found a high frequency of haemodynamically insignificant degenerative valvular lesions. Doppler left ventricular filling pattern of abnormal relaxation was a universal finding. CONCLUSION: There is a high prevalence of age-related echo-Doppler abnormalities in the self-reported healthy elderly with important implications for the interpretation of echo-Doppler studies.

Aged↗
PubMed1995

X-ray structure of gelonin at 1.8 A resolution.

Gelonin is a single chain ribosome inactivating protein (RIP) with potential application in the treatment of cancer and AIDS. Diffraction quality crystals grown using PEG3350, belong to the space group P21, with a = 49.4 A, b = 44.9 A, c = 137.4 A and beta = 98.4 degrees, and contain two molecules in the asymmetric unit. Diffraction data collected to 1.8 A resolution has a Rm value of 7.3%. Structure of gelonin has been solved by the molecular replacement method, using ricin A chain as the search model. Crystallographic refinement using X-PLOR resulted in a model for which the r.m.s deviations from ideal bond lengths and bond angles are 0.012 A and 2.7 degrees, respectively. The final R-factor is 18.4% for 39,806 reflections for which I > 1.0 sigma (I). The C alpha atoms of the two molecules in the asymmetric unit superpose to within 0.38 A for 247 atom pairs. The overall fold of gelonin is similar to that of other RIPs such as ricin A chain and alpha-momorcharin, the r.m.s.d. for C alpha superpositions being 1.3 and 1.4 A, respectively. The catalytic residues (Glu166, Arg169 and Tyr113) in the active site form a hydrogen bond scheme similar to that observed in other RIPs. The conformation of Tyr74 in the active site, however, is significantly different from that in alpha-momorcharin. Three well defined water molecules are located in the active site cavity, and one of them, X319, superposes to within 0.2 A of a corresponding water molecule in the structure of alpha-momorcharin. Any of the three could be the substrate water molecule in the hydrolysis reaction catalysed by gelonin. Difference electron density for a N-linked sugar moiety has been observed near only one of the two potential glycosylation sites in the sequence. The amino acid at position 239 has been established as Lys by calculation of omit electron density maps. The two cysteine residues in the sequence, Cys44 and Cys50, form a disulphide bond, and are therefore not available for disulphide conjugation with antibodies. Based on the structure, the region of the molecule that is involved in intradimer interactions is suggested to be suitable for introducing a Cys residue for purposes of conjugation with an antibody to produce useful immunotoxins.

Binding Sites↗