Search PubMed⌕ Search

Biomedical subjects

R Braithwaite

Publications and source records attributed to R Braithwaite.

At least 19 recordsLinked to original sources
PubMed2005

Blood lead levels in iron-deficient and noniron-deficient adults.

Iron deficiency (ID) has been reported to increase lead absorption. This relationship has been investigated in detail in children but not in adults. This study was designed to investigate whether blood lead levels are significantly higher in iron-deficient adults. ID-parameters (haemoglobin, mean corpuscular volume, mean corpuscular haemoglobin, serum iron, total iron-binding capacity, iron-binding saturation, soluble transferrin receptors, washed zinc protoporphyrin and ferritin) together with whole blood lead were measured in three different adult groups - blood donors (n = 73), pregnant women (n =74) and haemodialysis patients (n = 72). Of a total of 219 subjects tested, 7.7% was found to have a lead level above 10 microg/dl (maximum 16 microg/dl). No association was found between blood lead level and ID [iron-deficient subjects (n: 139), mean: 5.6 microg/dl (SD: 3 microg/dl) and noniron-deficient subjects (n: 80), mean: 5.4 microg/dl (SD: 3 microg/dl)]. The results suggest that the inverse association between blood lead and serum iron in studies carried out on children does not occur in adults.

Adult↗
PubMed2002

Interpretation of GC-MS opiate results in the presence of pholcodine.

Although the cross reactivity of pholcodine with opiate immunoassays has been well documented there is little published information the potential for pholcodine interference with chromatographic analyses. Wilson and Smith [Ann. Clin. Biochem. 36 (1999) 592] recently described the 'misidentification' of morphine in quality control specimens that had been spiked with pholcodine. This report describes a sensitive, rapid gas chromatography-mass spectrometry (GC-MS) method for the detection and quantitation of pholcodine and morphine, together with 6-monoacetylmorphine (6-MAM), codeine and dihydrocodeine in urine. This method was used to analyse urine specimens collected from volunteers given single and multiple doses of pholcodine to establish the significance this drug on the analytical results obtained when performing drug screening according to the proposed UK and EU legally defensible workplace drug testing guidelines. The maximum urinary free morphine concentration achieved following a single 10mg oral dose of pholcodine was 1.39 mg/l at 2-4h post dose. Following multiple 10mg oral doses of pholcodine the maximum urinary free morphine concentration was determined as 0.4 mg/l at 170 h after the final dose was administered. This apparent anomaly in the morphine concentrations obtained following single and multiple pholcodine doses can be explained in part by differences in the concentration of the specimens, and may be overcome by applying a correction factor for specimen dilution using their creatinine concentration. The data from this study suggests that even following one single 10mg dose of pholcodine, free morphine concentrations greater than both the proposed UK workplace drug testing guidelines threshold of 0.3mg/l total morphine and the proposed European Union threshold of 0.2mg/l total morphine can be achieved. This highlights the need for caution when interpreting confirmatory opiate data, especially in medicolegal and clinical cases, and in cases where the use of pholcodine is suspected.

Antitussive Agents↗
PubMed2002

A rapid GC-MS method for the determination of dihydrocodeine, codeine, norcodeine, morphine, normorphine and 6-MAM in urine.

The presence of the heroin metabolite 6-monoacetylmorphine (6-MAM) in urine is used to definitively identify recent heroin abuse. A rapid and sensitive GC-MS method for the simultaneous analysis of codeine, norcodeine, morphine, normorphine and 6-MAM in urine was developed and successfully applied to the analysis of 321 'heroin-positive' urine specimens from individual subjects (identified by the presence of 6-MAM), to provide quantitative urinary opiate excretion data for heroin abusers. The cohort analysed was composed of 238 males (age range 16-53 years) and 83 females (age range 16-50 years). The concentrations of free 6-MAM, morphine and codeine determined in these 321 specimens ranged between 103-246,312, 129-193,600 and 103-519,000 microg/l, respectively. Free norcodeine and normorphine concentrations were found to range between 143-50,200 and 205-149,700 microg/l, respectively. A statistically significant relationship was determined between the subject age and the 6-MAM concentration, possibly indicating opiate tolerance in these individuals.

Adolescent↗
PubMed2001

Tattooing and body piercing among adolescent detainees: relationship to alcohol and other drug use.

PURPOSE: The purpose of this preliminary study was to document self-reported tattooing and body piercing behavior among a sample of 860 adolescent detainees. Additionally, the study examined the relationship of alcohol and drug use to tattooing and body piercing--an often overlooked HIV risk behavior. METHODS: Adolescents (N = 860) participating in a substance use and HIV risk reduction intervention were surveyed upon entrance to a Youth Development Campus (YDC). RESULTS: Twenty-nine percent of the sample (N = 245) had at least one tattoo, and more than half (69%) had at least one body piercing. Fifteen percent had two or more tattoos, while 28% had three or more piercings. Although a small percentage of the youth reported knowingly sharing needles for tattoos or piercings (2% and 1.5%, respectively), 21% had tattoos that had been administered unprofessionally and 20% had unprofessionally administered piercings. Marijuana and alcohol were the highest reported substances used in this sample, 62% and 54%, respectively. Alcohol, marijuana, antidepressants, and sedatives were significant correlates of having tattoos. Alcohol was found to be a marginally significant (P = .052) correlate of body piercing. CONCLUSION: The popularity of tattooing and piercing and the risk involved with these activities make them an HIV risk behavior worthy of address. Risk reduction messages to youth should consistently address these behaviors and focus on them as they relate to substance use.

Adolescent↗
PubMed2000

Unprotected sex as a function of alcohol and marijuana use among adolescent detainees.

PURPOSE: To examine the relationship between the use of two substances (alcohol and marijuana) and the occurrence of unprotected sexual intercourse among adolescent detainees. METHODS: Participants were asked about their use of alcohol, marijuana, and condoms. In addition to comparing levels of alcohol and marijuana use, the study examined relationships among the following variables: (a) the number of days that each substance was used and the number of unprotected episodes of sexual intercourse in the 30 days preceding admission to a youth detention center; (b) the number of times that each substance was used before or during sexual intercourse and the number of unprotected episodes in the same time period; (c) the use of each substance and unprotected intercourse at the last sexual episode; and (d) intentions to use each substance in the context of sex and to have unprotected intercourse in the future. Relationships among these variables were assessed in four regression models, each of which included participants' demographic characteristics, AIDS knowledge, attitudes toward condoms, and future orientation as covariates. RESULTS: Results of all four regression models indicated that marijuana use was associated with unprotected sexual intercourse. Adolescents who used more marijuana in general as well as specifically in sexual episodes in the 30 days preceding detention reported higher levels of unprotected sex. In addition, marijuana use in the last episode was related to the occurrence of unprotected sex during that episode. Moreover, intentions to use marijuana in future sexual episodes was associated with intentions to have unprotected intercourse in the future. CONCLUSIONS: Future studies should use more rigorous research designs to clarify the nature of the relationship between marijuana use and risky sex.

Adolescent↗
PubMed1999

Predictors of homelessness among participants in a substance abuse treatment program.

Risk factors for homelessness were examined prospectively among recent participants in a substance abuse treatment program. Low levels of support from friends, greater depression, and recent substance use were bivariately associated with homelessness two months following completion of the program. However, friend support was the only factor associated with homelessness after controlling for other significant bivariate predictors.

Adult↗
PubMed1999

Knowledge of prophylaxis treatment therapy among HIV-positive prisoners.

The present study examined the level of knowledge and understanding of Pneumocystis Carinii Pneumonia (PCP) treatment therapy among heterosexual and non-heterosexual inmates (prisoners) with HIV-infection. This study seeks to determine if any differences exist between HIV-positive inmates based on sexual orientation, with reference to PCP treatment therapy. It is our contention that this effort will provide health professionals with valuable insight regarding delivering expanded care for HIV-infected individuals in incarcerated settings. The participants for this study were 99 HIV-positive inmates recruited between May and June 1995. These individuals were drawn from a list of all HIV/AIDS prisoners at the facility. More than 56% of the sample admitted their preferred sexual orientation as heterosexual compared to 43.4% non-heterosexual. More non-heterosexual seropositive inmates were likely to report PCP was preventable (OR = 1.17, 95% CI = 0.56, 2.42), as well as noting its contagious attributes (OR = 1.41, 95% CI = 0.90, 2.21). Furthermore, non-heterosexual inmates were more likely to report they were taking prescribed medications for their infections (OR = 1.34, 95% CI = 0.76, 2.36) and that they knew the names of the prescriptions they were taking (OR = 1.13, 95% CI = 0.59, 2.14). Regardless of sexual orientation, it is consistent with the research that HIV-positive individuals may engage in risky sexual behaviour that may place non-infected individuals at risk of contracting the virus. Prison provides an opportunity to provide education to multiple at-risk populations.

AIDS-Related Opportunistic Infections↗
PubMed1998

Opiate concentrations following the ingestion of poppy seed products--evidence for 'the poppy seed defence'.

The universally accepted 300 ng/ml cut-off limit for opiate assays stated to be mandatory for all drug screening laboratories by the Substance Abuse and Mental Health Services Administration, has been questioned recently due to positive results being obtained following the ingestion of poppy seed containing food products. To establish the plausibility of the 'the poppy seed defence' the concentrations of codeine, norcodeine, morphine, normorphine and thebaine (a potential marker for seed ingestion) in several varieties of poppy seeds from different countries were quantified by GC-MS. The country of origin of the seed specimen analysed and the preparation of the seeds prior to their culinary use was found to influence the alkaloid concentration determined. The maximum morphine and codeine concentrations determined in the seeds were found to be 33.2 and 13.7 micrograms/g seed respectively. In addition, thebaine concentrations were found to vary with each seed sample analysed. Following the consumption of bread rolls (mean 0.76 g seed covering per roll) by four subjects, all urine specimens analysed produced negative results (using the Dade Bebring EMIT II opiate screening assay) with the exception of one subject (body weight 63.0 kg) who consumed two poppy seed rolls. In this subject opiate positive screening results were obtained for up to 6 h post ingestion with maximum urinary morphine and codeine concentrations of 832.0 ng/ml (@ 2-4 h post ingestion) and 47.9 ng/ml (@ 0-2 h post ingestion) respectively being achieved. Following the ingestion of poppy seed cake containing an average of 4.69 g of seed per slice by four individuals, opiate positive screening results were obtained for up to 24 h. In one subject (dose equivalent to 0.07 g poppy seed/kg body weight) maximum urinary morphine and codeine concentrations of 302.1 ng/ml (@ 0-2 h) and 83.8 ng/ml (@ 2-4 h) respectively were recorded. The elimination of thebaine was found to vary widely between individuals, therefore suggesting that its absence from a specimen is not necessarily indicative of opiate abuse. These findings demonstrate that the poppy seed defence could be used as an argument in medico-legal and employment medical cases. Great care should therefore be taken when interpreting the data produced when screening for opiates.

Administration, Oral↗
PubMed1998

Prisoners' knowledge and attitude toward prophylactic treatment and therapy.

Identifying factors that hinder an inmate's compliance with Pneumocystis carinii pneumonia (PCP) prophylaxis therapy can be critical in preventing or decreasing the occurrence of PCP in this population. Anticipated factors include lack of knowledge about PCP and its proposed treatment, fear of the adverse effects of prophylaxis therapy, and lack of trust in the correctional facility medical team. Structured interviews were administered to HIV-positive male inmates chosen randomly (n = 104) at a medium- to maximum-security medical correctional facility located in the western portion of the United States. A basic "HIV 101 and Early Intervention" program encompassed the presentation of HIV facts and knowledge as well as safer sex practices. The results revealed that 95% of the respondents were knowledgeable about PCP and the side effects of their medications, and 56% of the respondents were afraid of the medications' side effects. Significant differences based on age were recorded for several specific knowledge questions, including the preventable nature of PCP.

AIDS-Related Opportunistic Infections↗
PubMed1994

Lack of effect of H2-receptor antagonists on the pharmacokinetics of alcohol consumed after food at lunchtime.

The possibility of a pharmacokinetic interaction between H2-receptor antagonists and alcohol consumed at lunchtime, was investigated in 24 healthy non-alcoholic male subjects, each receiving ranitidine 150 mg four times daily, cimetidine 400 mg four times daily, famotidine 20 mg four times daily and placebo in an open, four-way cross-over study. The subjects consumed 50 g alcohol after a standard lunch on the eighth day of dosing with study medication. Blood samples taken during the 6 h after alcohol consumption were analysed for alcohol concentrations by gas liquid chromatography using head space analysis. None of the H2-receptor antagonists had any statistically significant effects on any of the pharmacokinetic parameters for alcohol. Mean Cmax (95% CI) results for ranitidine were 547 (516, 580), cimetidine 531 (501, 563), famotidine 563 (530, 598) and placebo 529 (499, 561) mg l-1.

Adult↗
PubMed1993

Principles for forging a national health plan.

One point which has emerged with a resounding voice during this conference is the need to clearly assemble and carefully communicate data and information as a means of empowerment. We hope that the recommendations from this conference will contribute to this end. We urge all to become actively involved in seeking change, and ensuring that the future health of Americans and of our nation will not reflect our inequitable, costly present.

Cost Control↗
PubMed1982

Nortriptyline metabolism in chronic renal failure: metabolite elimination.

Single oral dose kinetics of nortriptyline and of tis two major metabolites, conjugated and unconjugated 20-hydroxynortriptyline, were studied in eight healthy subjects and 15 patients with chronic renal failure, five of whom were being treated with hemodialysis. Nortriptyline kinetics were unaltered, but the elimination of the metabolites was reduced in both groups of patients. In chronic renal failure the excretion of nortriptyline metabolites appeared to be the rate-limiting step in nortriptyline elimination. Three depressed hemodialysis patients were treated with nortriptyline (75 mg at night) for 6 wk. The ratios of the steady-state plasma concentrations of unconjugated 10-hydroxynortriptyline to nortriptyline (0.74 to 2.30) were in the same range as those in a control group of depressed patients with adequate renal function (0.53 to 4.08) who were also receiving nortriptyline. Conjugated 10-hydroxynortriptyline in renal failure patients was slow to reach steady-state concentrations and these were 10 to 20 times as high as those of the control depressed patients. Conjugated 10-hydroxynortriptyline in dialysis fluid during treatment showed that a mean 43 +/- 7% (SD) of the dose was removed by a 10-hr dialysis. Dialysis clearance of conjugated 10-hydroxynortriptyline was 58 +/- 8 (SD) ml min-1, but nortriptyline and unconjugated 10-hydroxynortriptyline were not appreciably removed by dialysis. Hemodialysis is not likely to be of value in the management of acute nortriptyline poisoning.

Adolescent↗
PubMed1982

Urinary excretion of 5-hydroxyindoleacetic acid--no relationship to the level in cerebrospinal fluid.

Concentrations of 5-hydroxyindoleacetic acid (5-HIAA) were determined in urine and cerebrospinal fluid (CSF) by mass fragmentography. A pronounced day-to-day variation in the urinary excretion of 5-HIAA was found both in psychiatric patients and a healthy control. Lumbar punctures performed twice 3-12 weeks apart in 11 healthy controls resulted in reproducible levels of 5-HIAA in CSF (r = 0.89; P less than 0.001). The mean of three periods of daily 5-HIAA excretion was not correlated to the CSF level measured in 18 psychiatric patients (r = 0.09). Three weeks of chlorimipramine treatment significantly decreased CSF 5-HIAA levels (P less than 0.05), but not the urinary excretion of 5-HIAA. It might be concluded that measurement of urinary 5-HIAA excretion is of little value compared to CSF levels in studies of serotonin in the central nervous system.

Clomipramine↗
PubMed1981

Quantitative determination of naproxen in plasma by a simple high-performance liquid chromatographic method.

A high-performance liquid chromatographic method for the determination of naproxen in plasma is described. The technique is based on the single extraction of the drug from acidified plasma with chloroform using 2-naphthalene acetic acid as internal standard. The chromatographic system consisted of a column packed with Spherisorb ODS (5 micrometer); the mobile phase was acetonitrile--phosphoric acid (pH 3) (45:55, v/v). The method can accurately measure plasma naproxen concentrations down to 1 microgram/ml using 100 microliter of sample, with no interference from endogenous compounds. The coefficients of variation of the method at 120 microgram/ml and 1 microgram/ml are 2.8 and 21.6%, respectively, and the calibration curve is linear. The method described is very suitable for routine clinical and pharmacokinetic studies.

Anti-Inflammatory Agents↗
PubMed1981

Comparison of the serum protein binding of maprotiline and phenytoin in uraemic patients on haemodialysis.

The serum protein binding of maprotiline and phenytoin has been compared in a group of 22 uraemic patients receiving haemodialysis. Determination of protein binding was carried out in vitro using equilibrium dialysis at 37 degrees C and 14C-labelled drug. The mean percentage unbound maprotiline found in patients (10.0%, SD 2.5) was not significantly different from that obtained in healthy volunteers (mean 10.5%, SD 1.0). However, there was a significantly increased variability in binding in patients compared with healthy subjects. The mean percentage unbound phenytoin in the same patients (22.2%, SD 3.3) was significantly greater than that obtained in healthy control subjects (12.5%, SD 0.6). Although there was no correlation between maprotiline and phenytoin binding and serum concentrations of alpha 1-acid glycoprotein, there was a significant correlation between percentage unbound maprotiline and serum albumin concentrations. The findings indicate that the binding of this tricyclic antidepressant is essentially normal in uraemia, although there may be increased interindividual variability in the free fraction of drug.

Adolescent↗
PubMed1981

The pharmacokinetics of nortriptyline in patients with chronic renal failure.

1 The pharmacokinetics of single oral doses of nortriptyline were studied in twenty patients with chronic renal failure, eight of whom were receiving treatment with haemodialysis. 2 The median nortriptyline half-life was 25.2 h (range 14.5-140.0 h) and the median nortriptyline clearance was 32.3 l/h (range 8.1-122.0 l/h). 3 No differences were observed between the dialysed and non-dialysed groups. 4 Comparisons of nortriptyline half-life and clearance between the patients and groups of physically healthy subjects revealed no significant differences. 5 There was no significant linear correlation between age and either of these measurements. In the twelve patients not receiving haemodialysis there was no correlation between nortriptyline clearance and glomerular filtration rate. 6 Chronic renal failure is not associated with a significant alteration in nortriptyline metabolism as measured by its half-life or clearance, but the drug should nonetheless be used with caution, and monitored whenever possible. However, the marked inter-individual differences observed in nortriptyline half-life and clearance in patients with chronic renal failure may not be solely responsible for their unpredictable response to tricyclic antidepressant therapy, and other possible contributory factors are discussed.

Adolescent↗