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PubMed2004

Changes in pulmonary vascular function after acute methionine loading in normal men.

Elevated blood levels of Hcy (homocysteine) are associated with endothelial dysfunction in the systemic and coronary arterial beds. We wished to know if similar changes could be detected in the pulmonary circulation, using non-invasive tests. We studied ten normal young men aged 23-31 years, in whom acute hyperhomocysteinaemia was induced by oral ingestion of methionine. Cardiopulmonary exercise testing [including measurement of exhaled breath NO (nitric oxide)] was performed on two occasions, with and without methionine loading. In addition, blood samples for vWf (von Willebrand factor) and factor VIIIc were taken as markers of endothelial function. After oral methionine, plasma Hcy increased from 11.8 +/- 3.1 to 31.2 +/- 10.3 micromol/l (values are means +/- S.D.; P < 0.0001), whereas there was no increase after placebo. After exercise there was an increase in V(NO) (NO production) and circulating plasma levels of vWf and factor VIIIc, but these were similar in the two tests. Exercise time, HR (heart rate) and BP (blood pressure) responses and P V(O2) (peak achieved O2 uptake) were also similar in the two tests. V(E) (expiratory minute ventilation)/ V(CO2) (CO2 production) was similar in the two groups at rest (methionine, 31.9 +/- 3.9; placebo, 30.5 +/- 3.9; P = 0.11), but increased during exercise after methionine (at peak, 32.2 +/- 4.6 compared with 29.9 +/- 2.8; P = 0.016). P(ETCO2) (end-tidal partial pressure of CO2) was also similar in the two groups at rest (35.1 +/- 2.9 compared with 36.8 +/- 3.2; P = 0.11), but decreased throughout the methionine test (peak 34.1 +/- 4.4 compared with 36.7 +/- 3.5; P = 0.006). V(E) vs V(CO2) slope also increased in the methionine test (25.2 +/- 2.4 compared with 22.8 +/- 2.3; P = 0.003). In conclusion, small, but consistent and significant, changes in respiratory gas exchange were seen after methionine loading, compatible with a V / Q (ventilation/perfusion) mismatch due to pulmonary vascular endothelial dysfunction.

Adult↗
PubMed2006

Exhaled nitric oxide measurements: clinical application and interpretation.

The use of exhaled nitric oxide measurements (F(E)NO) in clinical practice is now coming of age. There are a number of theoretical and practical factors which have brought this about. Firstly, F(E)NO is a good surrogate marker for eosinophilic airway inflammation. High F(E)NO levels may be used to distinguish eosinophilic from non-eosinophilic pathologies. This information complements conventional pulmonary function testing in the assessment of patients with non-specific respiratory symptoms. Secondly, eosinophilic airway inflammation is steroid responsive. There are now sufficient data to justify the claim that F(E)NO measurements may be used successfully to identify and monitor steroid response as well as steroid requirements in the diagnosis and management of airways disease. F(E)NO measurements are also helpful in identifying patients who do/do not require ongoing treatment with inhaled steroids. Thirdly, portable nitric oxide analysers are now available, making routine testing a practical possibility. However, a number of issues still need to be resolved, including the diagnostic role of F(E)NO in preschool children and the use of reference values versus individual F(E)NO profiles in managing patients with difficult or severe asthma.

Asthma↗
PubMed2004

Pharmacogenomics in breast cancer: current trends and future directions.

Pharmacogenomics is the study of genetic variations between individuals to predict the risk of toxic side effects and the probability that a patient will respond to single- or multidrug chemotherapy. Breast cancer remains one of the most common cancers among women worldwide and is second only to lung cancer in cancer-related death. A better understanding of the mechanisms of initiation and progression of breast cancer is needed for early diagnosis and development of better therapeutic methodologies. Differences in cancer patients' responses to chemotherapy have often been attributed to pathogenesis and severity of the disease, drug interactions, patient's age, gender, nutritional status, organ functions and tumor biology. It is now well recognized that genetic variations in drug target genes, disease pathway genes and drug metabolizing enzymes can have greater influence on drug efficacy and toxicity. In addition, germline variants can be used to study breast cancer susceptibility, as well as the variable response to both drug and radiation therapy used in the treatment of breast cancer. This review discusses clinically relevant individual gene variations that influence breast cancer susceptibility and cancer therapy, as well as the microarray-based expression profiling studies that have great potential in cancer pharmacogenomics in terms of tumor classification, drug and biomarker discovery and drug efficacy testing.

Age Factors↗
PubMedDate not supplied

DD23 Biomarker: a prospective clinical assessment in routine urinary cytology specimens from patients being monitored for TCC.

BACKGROUND: A prospective clinical study was conducted to assess the ability of the DD23 murine monoclonal antibody to enhance detection of bladder cancer in routine alcohol fixed urine cytology samples. METHODS: Prospectively, 308 bladder cytology specimens were obtained from patients with a history of bladder cancer with a mean age of 71.4+/-11.9 (27% female, 73% male). Data included 121 biopsy-confirmed results and 187 cystoscopy results to assess presence or absence of cancer. Thirty-five normal cytology specimens were obtained from asymptomatic men and women between 55-85 years of age. Separate slides from the alcohol fixed cytology specimens were stained using the Papanicolaou (Pap) and Feulgen staining procedures. The DD23 assay was performed using an avidin-biotin alkaline phosphatase immunocytochemical procedure, with a single urothelial cell exhibiting intense immunostaining sufficient to make a positive call. RESULTS: Pap-Feulgen cytopathology for the 308 cases yielded an overall sensitivity of 65.5% and a specificity of 85.1%, and the DD23 biomarker alone yielded a sensitivity of 80.5% and a specificity of 59.7%. Analysis of the voided urines only (n=164) yielded sensitivities of 61.0% and 73.2% and specificities of 86.2% and 67.5% for cytopathology and DD23 alone, respectively. Results in 49 bladder wash urine cytology cases produced a sensitivity of 70.2% and 100% and specificities of 92.3% and 61.5% for cytopathology and DD23 alone, respectively. In 133 patients that underwent biopsy or had positive cystoscopy results, cytopathology yielded a sensitivity of 65.5% and a specificity of 69.6% while DD23 yielded a sensitivity of 80.5% and a specificity of 58.7%. In 25 biopsy-confirmed low-grade cancers, DD23 improved cancer detection from 32% to 72% when compared to cytopathology. The DD23 biomarker had a specificity of 85.7% in 35 age-matched normal asymptomatic control specimens. CONCLUSIONS: The DD23 biomarker is an adjuvant test that provides improved detection of bladder cancer in cytology specimens and enhances the sensitivity of the cytopathology diagnosis, especially in low-grade cancers.

Adolescent↗
PubMed2005

Cut-off levels for breath carbon monoxide as a marker for cigarette smoking.

AIMS: Current clinical studies often use a breath carbon monoxide (BCO) cut-off level of 8 parts per million (p.p.m.) or higher to identify smoking. In this study, the cut-off level of BCO as an indicator of smoking over the past 24 hours was re-examined. DESIGN: BCO and self-reported smoking were obtained each weekday for up to 14 weeks in 213 subjects paid to deliver reduced BCO values. Analysis of 12 386 paired values for reported smoking and BCO were analyzed. FINDINGS: The 25% quartile, median and 75% quartile values for BCO were 1, 1 and 2 p.p.m. on non-smoking days and 2, 5 and 12 p.p.m. on smoking days, respectively. Receiver-operating characteristic (ROC) analysis indicated that BCO provided high diagnostic accuracy to distinguish between smoking and non-smoking days [area under the curve (AUC) = 0.853, P < 0.0001]. The highest combined sensitivity and specificity was observed at a BCO cut-off level of 3 p.p.m. (sensitivity = 71.5%; specificity = 84.8%). At a BCO cut-off of 8 p.p.m. sensitivity and specificity were 40.6% and 98.2%, respectively, indicating that many smokers would be falsely classified as abstinent. Finally, the percentage of true tests (positive and negative) was highest at a BCO cut-off of 2 p.p.m. (80.2%). CONCLUSIONS: BCO cut-off levels well below 8 p.p.m and as low as 2-3 p.p.m. may be more useful when it is important to maximize identification of smoking abstinence with a high degree of certainty.

Adult↗
PubMed2006

Declining plasma fibrinogen alpha fragment identifies HER2-positive breast cancer patients and reverts to normal levels after surgery.

Breast cancer is the most common nonskin malignancy affecting women. Currently, no simple, blood-based diagnostic test exists to complement radiological screening and increase sensitivity of detection. To screen plasma specimens and identify biomarkers that detect HER2-positive breast cancer, automated robotic sample processing followed by surface-enhanced laser desorption ionization time-of-flight (SELDI-TOF) mass spectroscopy was used. Multiple statistical algorithms were used to select biomarkers that segregate cancer patients versus controls and produced average CV rates ranging from 20% to 29%. A set of seven biomarkers were validated on an independent test data set and achieved the best error rate of 19.1%. A permutation test indicated a p-value for CV error less than 0.002. Moreover, a ROC curve using these biomarkers achieved an area-under-the-curve value of 0.95 on an independent test data set. The marker responsible for most of the resolving power was identified as a fragment of Fibrinogen Alpha (FGA) encompassing residues 605-629. This marker was present at lower levels in cancer patients as compared to controls. The importance of this biomarker was validated in a longitudinal study comparing pre- and post-operative levels and was shown to revert to normal levels after surgery. This fragment may serve as a useful diagnostic and treatment-monitoring marker.

Amino Acid Sequence↗
PubMed1999

Comparison of urinary 5-hydroxytryptophol, breath ethanol, and self-report for detection of recent alcohol use during outpatient treatment: a study on methadone patients.

This study compared urinary 5-hydroxytryptophol (5HTOL) with breath-ethanol testing as objective ways to disclose recent drinking by outpatients attending a methadone maintenance treatment clinic. Information about quantity and frequency of alcohol use was obtained by confidential self-reports. Random screening was performed on Mondays-Fridays in connection with routine clinic visits for methadone dosing. An observed urine sample for monitoring of illicit drug use and determination of 5HTOL, expressed as a ratio to 5-hydroxyindole-3-acetic acid (5HIAA), was obtained from 202 patients (59 women and 143 men), 16 of whom refused to complete the self-report and/or do a breath-ethanol test. Patients taking disulfiram or calcium carbimide for alcohol detoxification were excluded. Among the 177 subjects remaining, 47 (26.6%) reported intake of any alcohol on the previous day (range, 10-230 g ethanol; median, 40). Only four of those could be identified by a positive breath-test, while 17 showed a urinary 5HTOL/5HIAA ratio above the cutoff limit. Their alcohol consumption (median, 60 g) was significantly higher compared with those showing ratios within the reference interval (median, 35 g). The sensitivity of 5HTOL/5HIAA testing for detecting self-reported drinking in excess of 50 g ethanol was 77%. An additional nine patients who claimed abstinence still showed abnormal 5HTOL/5HIAA ratios, and so did three of the patients who refused to do a breath-ethanol test and/or complete the self-report. Altogether, 59 of 190 methadone-maintained patients (31.1%) had been drinking any alcohol on the previous day (i.e. Sunday-Thursday) according to self-report and/or urinalysis data, 29 (49.2%) of whom were identified by the urinary 5HTOL/5HIAA ratio and only four (6.8%) by utilizing breathalyzer.

Alcohol Drinking↗
PubMed1998

Mutagen content and metabolic activation of promutagens by molluscs as biomarkers of marine pollution.

Organisms combat pollutants by inducing biotransformation pathways, which can be used for biomonitoring. Several parameters--biomarkers--change in stressed organisms or populations at different organisation levels. Molecular or cellular biomarkers are early-warning indicators of pollution. Xenobiotics are first biotransformed by phase I enzymes and then conjugated with endogenous metabolites by phase II enzymes. Many organic xenobiotics are initially biotransformed by cytochrome P4501A1; in mammals, it is induced by pollutants via Ah receptor, although in marine invertebrates, its inducibility is much more equivocal. Metallothioneins are small Cys-rich proteins which bind transition metals; they detoxicate pollutant metals and are clearly induced in metal-exposed marine invertebrates. Some pollutants are genotoxins or can be converted into them. Determination of mutagens in bivalve molluscs following extraction with solvents and assay of mutagenicity with bacterial tests is a useful biomarker for marine pollution. While some pollutants are directly mutagenic, others are only mutagenic after they are activated to mutagenic derivatives by monooxygenases or conjugative enzymes. Many of these catalysts are induced by xenobiotics; thus, increased activation of known promutagens can be used as biomarker of environmental pollution. Bioactivation of promutagens requires the simultaneous action of different pathways, thus, reproducing more closely the in vivo situation than the specific assay of individual biotransforming enzymes. Study of molluscs with different pollution levels indicates that polluted animals have higher capacity to activate 2-aminoanthracene and contain more apolar mutagens than those from reference areas.

Animals↗
PubMed2001

2-Methoxyethanol metabolism, embryonic distribution, and macromolecular adduct formation in the rat: the effect of radiofrequency radiation-induced hyperthermia.

Exposure of pregnant rats to the solvent 2-methoxyethanol (2ME) and radiofrequency (RF) radiation results in greater than additive fetal malformations (Nelson, B.K., Conover, D.L., Brightwell, W.S., Shaw, P.B., Werren, D.W., Edwards, R.M., Lary, J.M., 1991. Marked increase in the teratogenicity of the combined administration of the industrial solvent 2-methoxyethanol and radiofrequency radiation in rats. Teratology 43, 621-34; Nelson, B.K., Conover, D.L., Shaw, P.B., Werren, D.W., Edwards, R.M., Hoberman, A.M., 1994. Interactive developmental toxicity of radiofrequency radiation and 2-methoxyethanol in rats. Teratology 50, 275-93). The current study evaluated the metabolism of 14C-labeled 2ME and the distribution of methoxyacetic acid (MAA) in maternal and embryonic tissues of pregnant Sprague-Dawley rats either exposed to 10 MHz RF radiation or sham conditions. Additionally, adduct formation for both plasma and embryonic protein was tested as a possible biomarker for the observed 2ME/RF teratogenicity. Rats were administered [ethanol-1,2-(14)C]-2ME (150 mg/kg, 161 microCi/rat average) by gavage on gestation day 13 immediately before RF radiation sufficient to elevate body temperature to 42 degrees C for 30 min. Concurrent sham- and RF-exposed rats were sacrificed at 3, 6, 24 or 48 h for harvest of maternal blood, urine, embryos and extra-embryonic fluid. Tissues were either digested for determination of radioactivity or deproteinized with TCA and analyzed by HPLC for quantification of 2ME metabolites. Results show the presence of 2ME and seven metabolites, with the major metabolite, MAA, peaking at 6 h in the tissues tested. MAA, the proximal teratogen, was detectable in maternal serum, urine, embryo and extraembryonic fluid 48 h after dosing. Clearance of total body 14C was significantly reduced for the RF-exposed animals (P<0.05) for the 24-48 h period, but MAA values for serum, embryos and extraembryonic fluid were similar for both sham- and RF-exposed rats. Additionally, no difference was noted for 2ME metabolite profiles in urine or tissue for sham- or RF-exposed rats, thus eliminating an effect of RF radiation on MAA production as a possible explanation for the reported RF-2ME synergism. Subsequently, serum and embryo protein-bound adducts were evaluated by analysis of covalently bound radioactivity. Serum protein binding was significantly higher for sham than RF rats at 3- and 6-h - highest for sham rats at 6 h (519+/-95 microg as parent 2ME/g of protein) whereas RF serum values were highest at 24 h (266+/-79 microg/g protein). Embryonic protein binding was significantly higher for sham rats at 6 h, but binding was highest for both groups at 24 h (sham=229+/-71 microg/g, RF=185+/-48 microg/g). Formation of protein adducts after 2ME is thought to be related to levels of methoxyacetaldehyde, a reactive intermediate in the formation of MAA. These results suggest that no direct relationship exists for covalent binding in the embryo which would explain RF-2ME synergistic malformations. In comparison with urinary metabolites, the relatively slow elimination of adducted serum 2ME indicates that analysis of protein-bound concentrations could be a potential tool for long- term biomonitoring of worker exposure.

Acetates↗
PubMed2004

Genetic basis of pulmonary arterial hypertension: current understanding and future directions.

Mutations in two receptors of the transforming growth factor-beta family have recently been shown to be present in the majority of cases of inherited (familial) pulmonary arterial hypertension (PAH). Study of the biology of these receptors, bone morphogenetic protein receptor type-2 (BMPR2), and activin-like kinase type-1 (ALK-1) will certainly reveal pathogenic mechanisms of disease. Exonic mutations in BMPR2 are found in about 50% of patients with familial PAH, and ALK1 mutations are found in a minority of patients with hereditary hemorrhagic telangiectasia and co-existent PAH. Because familial PAH is highly linked to chromosome 2q33, it is likely that the remaining 50% of family cases without exonic mutations have either intronic BMPR2 abnormalities or alterations in the promoter or regulatory genes. Also, only about 10% of patients with "sporadic" idiopathic PAH have identifiable BMPR2 mutations. Mutations in BMPR2 confer a 15% to 20% chance of developing PAH in a carrier's lifetime. Thus, there must be gene-gene or gene-environment interactions that either enhance or prevent the development of the vascular disease in persons carrying a mutation, and there must be other patterns of susceptibility based on genetic makeup. To elucidate the genetic basis of PAH further, investigations are needed, including genome scanning for major and minor genes, analysis of genetic profiles of patients for candidate genes likely to modify risk for disease (e.g., serotonin transporter alleles, nitric oxide-synthases), proteomics, transgenic mice, and altered signal transduction. Advances in genetic testing, presymptomatic screening, and biomarkers should permit early detection of disease in those at risk of PAH and allow trials of preventive therapy in carriers.

Animals↗
PubMed2005

Possibilities and pitfalls for modern biotechnology in the development of African genetic toxicology.

Developing countries are currently going through a transitional phase facing the new challenges of globalization and its potential negative impact. Research policy should highlight the need to mobilize resources for human resource development, networking, improved research culture, information sharing, and pragmatic use of research findings. Advancement in molecular genetics whether at the educational or research level should greatly progress in developing countries so as to improve diagnosis, treatment, understanding of disease risk factors, and prevention. Currently, there is a growing interest to genetic toxicology research, the use of different biomarkers, and genetic susceptibility testing, which can contribute effectively in risk assessment. Africa has unique environmental exposures and public health circumstances, which make it ideal for environmental mutagenicity and carcinogenicity research. There are exposures to chemical genotoxicants (e.g., automobile exhaust, pesticides, metals, and cytotoxic drugs) and to lifestyle factors (e.g., consumption of tobacco products) that have been linked to the expression of biological effects and to increased risk for cancer. Infections can be associated with cancer development when the environmental factors interact with the infection and lead to the enhancement of the carcinogenic process. The high prevalence of viral pathogens and the improper use of pesticides may endanger biological functions beyond those for which they originally manufactured. Biomarkers are used to detect the effects of pesticides before adverse clinical health occurs. The scientific community plays a crucial role in understanding the environmental causes of human health problems and through its collaboration with communities, industries, and government agencies can help in resolving health problems.

Biotechnology↗
PubMed2003

Delta (13)C-urea breath test value is a useful indicator for Helicobacter pylori eradication in patients with functional dyspepsia.

BACKGROUND: Eradication of Helicobacter pylori is not routinely recommended for the symptomatic relief and the prevention of gastric cancer in patients with functional dyspepsia. The present study investigated a useful indicator of H. pylori eradication in such patients by determining the optimal cutoff value of a 13C-urea breath test (UBT). METHODS: One hundred dyspeptic patients participated in the study. Dyspepsia was scored, and a 13C-UBT administered. A level of delta 13C-UBT of>4 per thousand was diagnosed as H. pylori-positive. After the stomach was endoscopically sprayed with phenol red, biopsy specimens were taken from the antrum, body and cardia of the stomach for the assessment of H. pylori density, and activity (neutrophil infiltration) and degree (lymphocyte infiltration) of gastritis. RESULTS: Correlation between delta 13C-UBT and dyspepsia score was not found. Delta 13C-UBT significantly correlated with H. pylori density score in the total stomach (r = 0.53, P < 0.0001), neutrophil (r = 0.34, P = 0.0005) and lymphocyte score (r = 0.69, P < 0.0001). Twenty-six of the 100 subjects had a neutrophil score of >or=4, lymphocyte score of >or=4, and H. pylori score of >or=4. Their 95% confidence interval of mean was 58.2 per thousand, which reflects moderate to marked acute and chronic gastritis, and dense H. pylori colonization. CONCLUSIONS: The 13C-UBT is a reliable semiquantitative test to assess H. pylori density and the activity and degree of gastritis. It is proposed that H. pylori eradication therapy might be beneficial for patients with functional dyspepsia with a delta 13C-UBT of >58.2 per thousand.

Adult↗
PubMed2000

[The relationship between stages and biochemical markers of smoking. Workplace-based cross-sectional and longitudinal studies].

In order to clarify smokers' characteristics by "Stages of Change" based on Prochaska's transtheoretical model, we conducted cross-sectional and logitudinal studies with biochemical markers of smoking and smoking habits. In a workplace-based sample of 277 male smokers, we examined cross-sectionally the relationships between stages and biochemical markers of smoking which include expired carbon monoxide concentrations and urinary nicotine metabolite concentrations, and smoking habits which include the number of cigarettes smoked per day, yields of cigarettes, inhalation patterns, time to first morning cigarette, and quit attempts in the past. Additionally we examined longitudinally the relationship between stages and expired carbon monoxide concentrations, the number of cigarettes, and yields of cigarettes. In the cross-sectional study there were significant differences among stages on expired carbon monoxide concentrations (P = 0.006), urinary nicotine metabolite concentrations (P = 0.049), the number of cigarettes smoked per day (P = 0.001), and yields of cigarettes (P = 0.042) using analyses of variance. There were also significant differences among stages on time to first morning cigarette (P = 0.018) and quit attempts in the past (P < 0.001) using chi-square tests. In the longitudinal study for each level of elevation in stage during a one-year period, expired carbon monoxide concentrations decreased on an average of 2.3 ppm (P = 0.125) and the number of cigarettes smoked per day decreased on an average of 2.8 cigarettes per day (P = 0.07). However, the yields of cigarettes did not change during the one-year period.

Adult↗
PubMed1997

Determination of carcinogenic potential of mineral fibers by 8-hydroxydeoxyguanosine as a marker of oxidative DNA damage in mammalian cells.

8-Hydroxydeoxyguanosine (8-OH-dG) is a typical form of oxidative DNA damage, which causes mutations in vitro and in vivo. To develop a simple method of testing the carcinogenicity of fibrous materials, the formation of 8-OH-dG was determined in the DNA of J774 cells, an established reticulum cell sarcoma line, after treatment with various natural and man-made mineral fibers. The amount of 8-OH-dG was determined using high-pressure liquid chromatography (HPLC) equipped with an electrochemical detector (ECD). We tested three natural mineral fibers (crocidolite, amosite, and chrysotile) and three man-made mineral fibers (ceramic, glass, and potassium octatitanate). Among them, a significant increase in 8-OH-dG formation was observed in the crocidolite- and amosite-treated cells. We also measured the amount of tumor necrosis factor (TNF) produced by J774 cells incubated with the fibrous materials. Cellular TNF production increased after treatment with all the fibers tested, but it was not statistically significant except in the case of chrysotile. Therefore, these results indicate that the mechanism of TNF production is different from that of 8-OH-dG formation, and that the carcinogenicity of various fibrous materials can be better evaluated by measuring the 8-OH-dG level in J774 cellular DNA after treatment with these fibers.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1994

The potential of the hydrocarbon breath test as a measure of lipid peroxidation.

The straight chain aliphatic hydrocarbons ethane and pentane have been advocated as noninvasive markers of free-radical induced lipid peroxidation in humans. In in vitro studies, the evolution of ethane and pentane as end products of n-3 and n-6 polyunsaturated fatty acids, respectively, correlates very well with other markers of lipid peroxidation and even seems to be the most sensitive test available. In laboratory animals the use of both hydrocarbons as in vivo markers of lipid peroxidation has been validated extensively. Although there are other possible sources of hydrocarbons in the body, such as protein oxidation and colonic bacterial metabolism, these apparently are of limited importance and do not interfere with the interpretation of the hydrocarbon breath test. The production of hydrocarbons relative to that of other end products of lipid peroxidation depends on variables that are difficult to control, such as the local availability of iron(II) ions and dioxygen. In addition, hydrocarbons are metabolized in the body, which especially influences the excretion of pentane. Because of the extremely low concentrations of ethane and pentane in human breath, which often are not significantly higher than those in ambient air, the hydrocarbon breath test requires a flawless technique regarding such factors as: (1) the preparation of the subject with hydrocarbon-free air to wash out ambient air hydrocarbons from the lungs, (2) the avoidance of ambient air contamination of the breath sample by using appropriate materials for sampling and storing, and (3) the procedures used to concentrate and filter the samples prior to gas chromatographic determination. For the gas chromatographic separation of hydrocarbons, open tubular capillary columns are preferred because of their high resolution capacity. Only in those settings where expired hydrocarbon levels are substantially higher than ambient air levels might washout prove to be unnecessary, at least in adults. Although many investigators have concentrated on one marker, it seems preferable to measure both ethane and pentane concurrently. The results of the hydrocarbon breath test are not influenced by prior food consumption, but both vitamin E and beta-carotene supplementation decrease hydrocarbon excretion. Nevertheless, the long-term use of a diet high in polyunsaturated fatty acids, such as in parenteral nutrition regimens, may result in increased hydrocarbon exhalation. Hydrocarbon excretion slightly increases with increasing age. Short-term increases follow physical and intellectual stress and exposure to hyperbaric dioxygen.(ABSTRACT TRUNCATED AT 400 WORDS)

Basal Metabolism↗
PubMed1994

A comparison of carbohydrate deficient transferrin with other markers of alcohol misuse in male soldiers under the age of thirty.

The paper describes a study of 58 consecutive male soldiers under 30 years old admitted to an alcohol treatment unit in London, and 51 age- and gender-matched controls to compare the efficacy of isoelectric focusing, a non-quantitative measure of carbohydrate deficient transferrin (CDT), with other markers of alcohol misuse. The Severity of Alcohol Dependence Questionnaire, the Michigan Alcohol Screening Test and the CAGE questions were all more sensitive in detecting alcohol misusers than the laboratory markers measured. At standard cut-off levels, the laboratory markers yielded low sensitivities even in those subjects who admitted to drinking over 80 g alcohol daily for at least 3 weeks immediately prior to the study. CDT was the most sensitive (31%), followed by mean cell volume (14%) and gamma glutamyl transferase (11%). The questionnaires and laboratory markers had good specificities.

Adult↗