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Observational studies have suggested that low serum [beta]-carotene concentrations may influence HIV-1 disease progression. However, randomized trials have not demonstrated beneficial effects of [beta]-carotene supplementation. To understand this discrepancy, we conducted a cross-sectional study among 400 HIV-1-seropositive women in Mombasa, Kenya, to correlate serum [beta]-carotene concentrations with several measures of HIV-1 disease severity. [beta]-Carotene concentrations were significantly associated with biologic markers of HIV-1 disease progression (CD4 count, HIV-1 plasma viral load, serum C-reactive protein [CRP] concentration, and serum albumin level). In multivariate analysis, [beta]-carotene concentrations below the median were associated with elevated CRP (>10 mg/l, adjusted odds ratio [aOR] 3.32, 95% confidence interval [CI] 1.99-5.53, P < 0.001) and higher HIV-1 plasma viral load (for each log10 copies/mL increase, aOR 1.38, 95% CI 1.01-1.88, P = 0.04). In the context of negative findings from randomized trials of [beta]-carotene supplementation in HIV-1-seropositive individuals, these results suggest that low [beta]-carotene concentrations primarily reflect more active HIV-1 infection rather than a deficiency amenable to intervention. [ABSTRACT FROM AUTHOR]

Universal screening of potential organ donors and recipients for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is now recommended prior to transplantation in the United States during the coronavirus disease 19 (COVID-19) pandemic. Challenges have included limited testing capacity, short windows of organ viability, brief lead time for notification of potential organ recipients, and the need to test lower respiratory donor specimens to optimize sensitivity. In an early U.S. epicenter of the outbreak, we designed and implemented a system to expedite this testing and the results here from the first 3 weeks. The process included a Laboratory Medicine designee for communication with organ recovery and transplant clinical staff, specialized sample labeling and handoff, and priority processing. Thirty-two organs recovered from 14 of 17 screened donors were transplanted vs 70 recovered from 23 donors during the same period in 2019. No pretransplant or organ donors tested positive for SARS-CoV-2. Median turnaround time from specimen receipt was 6.8 hours (donors), 6.5 hours (recipients): 4.5 hours faster than daily inpatient median. No organ recoveries or transplantations were disrupted by a lack of SARS-CoV-2 testing. Waitlist inactivations for COVID-19 precautions were reduced in our region. Systems that include specialized ordering pathways and adequate testing capacity can support continued organ transplantation, even in a SARS-CoV-2 hyperendemic area., (© 2020 The American Society of Transplantation and the American Society of Transplant Surgeons.)

To optimize transportation processes, we present herein a contingency plan that coordinates interim measures used to ensure continued and timely services when climate based events might cause an interruption of the usual specimen transportation processes. As an example, we outline the implementation and effectiveness of a contingency plan for network laboratory courier automobile transportation during times of mountain pass highway closure. Data available from an approximately 3-year period from October 10, 2010 through August 29, 2013 revealed a total of 690 complete closures in the eastbound or westbound lanes of the Interstate-90 highway in the Snoqualmie Pass area in the state of Washington. Despite the frequency of closures, the Washington State Department of Transportation was effective in limiting the duration of closures. Road closures of less than 1 hour accounted for 58.7% of the total closures. No recorded closures prevented dispatched couriers from completing a prescheduled Snoqualmie Pass route. We identified no delays as being clinically significant, despite that there were 5 instances of delays greater than 4 hours. We implemented a contingency plan of aiding courier logistics during all times of pass closure. The plan includes an easy to interpret Condition Dashboard as a status indicator and a Decision Tree that references and summarizes information. Overall, the contingency plan allows for an objective, robust, proactive decision support system that has enabled operational flexibility and has contributed to continued safe, on-time specimen transportation; clients and courier and reference laboratory staff have appreciated these features and associated outcomes., (Copyright© by the American Society for Clinical Pathology (ASCP).)

Background: Chemiluminescence immunoassay (CIA) is used to detect hepatitis C virus (HCV) antibody status on the basis of signal-to-cutoff (S/Co) ratios. Positive results of antibody to HCV (anti-HCV) are followed by either recombinant immunoblot assay (RIBA) to confirm anti-HCV positivity or reverse transcription (RT)-PCR to detect viremia. We hypothesized that by analyzing S/Co ratios, we could determine a strategy to reduce unnecessary supplementary testing in our population., Methods: CIA was performed to screen for anti-HCV, and positive results were followed up with RT-PCR testing. Negative RT-PCR results were followed up with RIBA, whereas positive RT-PCR results were assumed to be RIBA positive. ROC curves were analyzed to determine the optimal S/Co ratios to predict HCV infection., Results: We determined the S/Co ratios on 34 243 veteran patient samples. We found that with the CIA method 9.0% of patients had positive test results for anti-HCV. An S/Co ratio <3.0 ruled out active HCV infection and exposure with 100% negative predictive value. When the S/Co ratio was ≥20.0, positive predictive values were 98.5% compared with RIBA results, and 81.0% compared with RT-PCR results., Conclusions: RIBA is not necessary to confirm negative or positive CIA anti-HCV if the S/Co ratio is <3.0 or ≥20.0, respectively. To confirm HCV exposure, samples with an S/Co ratio between 3.0 and 19.9 should be followed up with RIBA unless PCR testing has been performed and the result is positive. Samples with an S/Co ratio ≥20.0 or positive RIBA results should be further tested by RT-PCR to determine HCV viremia status.

Free testosterone (FT) measurement by equilibrium dialysis and liquid chromatography-tandem mass spectroscopy (LCMS/MS) is the "gold standard." We hypothesized that calculated FT values could substitute for measured values; compared FT results reported by Walter Reed Army Medical Center (WRAMC), Washington, DC, with results reported by the Seattle Veterans Affairs Health Care System, Seattle, WA, for 3 patient groups; and evaluated the calculated FT values by gold-standard measurements. Groups 1 and 2 included samples from 54 patients evaluated in Seattle and 94 evaluated at a primary care clinic in Alaska whose samples were analyzed in Seattle, respectively, whose care resulted in ordering an FT measurement. Group 3 included samples from 64 patients evaluated in endocrine WRAMC clinics. Calculated FT values between the 2 facilities demonstrated a strong correlation (R2 = 0.98) for all 212 patients. In a comparison of calculated FT values with measured levels, group 3 had an R2 = 0.93; however, samples with FT values less than 50 pg/mL had a poorer correlation (R2 = 0.45). Calculated FT values may accurately reflect and be substituted in the clinical setting for gold-standard values when levels are more than 50 pg/mL.

Objective: The purpose of this study was to determine the relationship between plasma liver enzyme concentrations, insulin sensitivity, and intra-abdominal fat (IAF) distribution., Research Design and Methods: Plasma gamma-glutamyl transferase (GGT), aspartate transaminase (AST), alanine transaminase (ALT) levels, insulin sensitivity (insulin sensitivity index [S(I)]), IAF area, and subcutaneous fat (SCF) area were measured in 177 nondiabetic subjects (75 men and 102 women, aged 31-75 years) with no history of liver disease. On the basis of BMI (< or > or = 27.5 kg/m2) and S(I) (< or > or = 7.0 x 10(-5) min/pmol) subjects were divided into lean insulin sensitive (LIS, n = 53), lean insulin resistant (LIR, n = 60), and obese insulin resistant (OIR, n = 56) groups., Results: Levels of all three liver enzymes were higher in men than in women (P < 0.0001 for each). In men, GGT levels were higher in insulin-resistant than in insulin-sensitive subjects (P < 0.01). In women, GGT levels were higher in the OIR than in the LIS group (P < 0.01) but no different in the LIR group. There was no difference in ALT and AST levels among the LIS, LIR, and OIR groups. GGT was associated with S(I) (r = -0.26, P < 0.0001), IAF area (r = 0.22, P < 0.01), waist-to-hip ratio (WHR) (r = 0.25, P = 0.001), BMI (r = 0.17, P < 0.05), and SCF area (r = 0.16, P < 0.05) after adjustments for age and sex. In men, only S(I) (r = -0.29, P < 0.05) remained independently correlated with GGT in multiple regression analysis. In women, IAF area (r = 0.29, P < 0.01) and WHR (r = 0.29, P < 0.01) were independently associated with GGT, but S(I) was not., Conclusions: In nondiabetic men GGT but not AST or ALT levels, are inversely related to insulin sensitivity independent of IAF area. However in women, GGT is related to measures of central body fat rather than to insulin sensitivity.

Background: Low vitamin E levels are often found in HIV-1 infection, and studies have suggested that higher levels may decrease the risk of disease progression. However, vitamin E supplementation has also been reported to increase CCR5 expression, which could increase HIV-1 replication. We hypothesized that vitamin E levels at HIV-1 acquisition may influence disease progression., Methods: Vitamin E status was measured in stored samples from the last pre-infection visit for 67 Kenyan women with reliably estimated dates of HIV-1 acquisition. Regression analyses were used to estimate associations between pre-infection vitamin E and plasma viral load, time to CD4 count <200 cells/muL, and mortality., Results: After controlling for potential confounding factors, each 1 mg/L increase in pre-infection vitamin E was associated with 0.08 log10 copies/mL (95% CI -0.01 to +0.17) higher set point viral load and 1.58-fold higher risk of mortality (95% CI 1.15-2.16). The association between higher pre-infection vitamin E and mortality persisted after adjustment for set point viral load (HR 1.55, 95% CI 1.13-2.13)., Conclusion: Higher pre-infection vitamin E levels were associated with increased mortality. Further research is needed to elucidate the role vitamin E plays in HIV-1 pathogenesis.

The ratio of retinol-binding protein (RBP) to transthyretin (TTR) has been proposed as an indirect method with which to assess vitamin A status in the context of inflammation. Few studies have been conducted among adults, and none examined the effect of HIV-1 infection. Our goal was to assess the RBP:TTR ratio among adults, including the effects of HIV-1 and the acute phase response. We used data from a cross-sectional study of 600 Kenyan women, of whom 400 had HIV-1. The effect of vitamin A supplementation among the HIV-1-infected participants was subsequently assessed in a randomized trial. Among HIV-1-uninfected women without an acute phase response, a RBP:TTR cut-off value of 0.25 had approximately 80% sensitivity and specificity to detect vitamin A deficiency (retinol <0.70 micromol/L). No RBP:TTR cut-off value demonstrated both high sensitivity and specificity among HIV-1 infected women without evidence of inflammation. HIV-1 infection and advanced HIV-1 disease were associated with higher RBP:TTR ratios. The effect of HIV-1 was independent of the acute phase response, which also increased the RBP:TTR ratio. Serum retinol increased with vitamin A supplementation among those with a low RBP:TTR ratio, although the effect was small and was not present among those with concurrent inflammation. Thus, the RBP:TTR ratio has modest ability to predict vitamin A deficiency among healthy adults, but HIV-1 infection alters the ratio, even in the absence of the acute phase response. Our results raise questions about the utility of this measurement given the high prevalence of HIV-1 infection in areas where vitamin A deficiency is common.

Background: Low serum selenium has been associated with lower CD4 counts and greater mortality among HIV-1-seropositive individuals, but most studies have not controlled for serum albumin and the presence of an acute phase response., Methods: A cross-sectional study was conducted to evaluate relationships between serum selenium concentrations and CD4 count, plasma viral load, serum albumin, and acute phase response markers among 400 HIV-1-seropositive women., Results: In univariate analyses, lower CD4 count, higher plasma viral load, lower albumin, and the presence of an acute phase response were each significantly associated with lower serum selenium concentrations. In multivariate analyses including all four of these covariates, only albumin remained significantly associated with serum selenium. For each 0.1 g/dl increase in serum albumin, serum selenium increased by 0.8 microg/l (p < 0.001). Women with an acute phase response also had lower serum selenium (by 5.6 microg/l, p = 0.06)., Conclusion: Serum selenium was independently associated with serum albumin, but not with CD4 count or plasma viral load, in HIV-1-seropositive women. Our findings suggest that associations between lower serum selenium, lower CD4 count, and higher plasma viral load may be related to the frequent occurrence of low serum albumin and the acute phase response among individuals with more advanced HIV-1 infection.

This study evaluated serum kappa and lambda free light chain (FLC) concentrations in a Veterans Affairs (VA) population. We hypothesized that our older, mostly male, population should not differ in serum FLC ranges from levels previously established for younger male and female populations and that the assay would improve our screening protocol for plasma cell dyscrasias (PCD). Serum kappa and lambdaFLC were assayed in 312 consecutive serum samples collected during a 16-week period from veterans whose clinical presentation indicated a need for serum protein electrophoresis (SPEP) analysis. We reviewed our laboratory information system (LIS) files to evaluate the patients' diagnoses and treatment status in conjunction with serum FLC levels. All assays and validation studies were conducted using an immunoturbidimetric method with a Roche/Hitachi 911 modular analytical system. The intra-assay variability (CV) was <5%, based on 13 replicate assays of 4 control samples and 1 blank sample. Of the 312 patients, the SPEP results were normal in 235 and abnormal in 77. Of the 235 patients with normal SPEP results, 37 had abnormal FLC values and 20 of these were diagnosed as PCD. Of the 77 patients with abnormal SPEP results, only 9 had diagnoses unrelated to PCD. Using the FLC assay in conjunction with retrospective reviews of medical records, we obtained an 86% detection rate of PCD. This detection rate increased to 100% when both SPEP and FLC results were considered. In conclusion, this study documents an important role for serum FLC assays in diagnosing and monitoring PCD in a VA population. Our results support previously established serum FLC reference ranges that were obtained in younger, male and female populations. Using the serum FLC results in conjunction with SPEP results improves the sensitivity and specificity for managing VA patients whose clinical presentation indicates the need to evaluate PCD.

Background: Sex hormone binding globulin (SHBG) is an important regulator of testosterone and estradiol., Study Design: We validated the Diagnostic Products Corporation (DPC) and Roche Diagnostic SHBG immunoassays on the DPC Immulite 2000 and Roche Modular E170 analyzers., Results: The coefficient of variation for SHBG kits from both manufacturers was in the range of 3.9-7.7% (between-run) and 0.95-5.0% (within-run), free of interference from hemoglobin, bilirubin, lipid, and rheumatoid factor, and linear up to at least 170 nM SHBG. The results of the two methods, however, were biased by up to 29% depending on the SHBG concentration., Conclusion: The SHBG assays perform well but standardization is needed.

The purpose of this study was to validate the Albumin Cobalt Binding (ACB) assay at the Seattle Veterans Affairs (VA) Hospital to determine if it would provide an earlier rule-out of acute coronary syndrome (ACS) in patients, compared to current use of cardiac injury markers. This study compares the distribution of ischemia modified albumin (IMA) values of our patient population to those provided by the kit manufacturer. IMA values were determined photometrically on a Roche Modular Analytical System on 200 subjects: 69 subjects not experiencing chest pain (normals), 78 subjects presenting to the emergency room (ER) with chest pain whose initial and subsequent troponin results were negative (non-converters), and 53 subjects presenting to the ER with chest pain whose initial troponin result was negative but subsequent troponin results were positive (converters). Based on the relationships between IMA values in the initial samples from the non-converters and converters, we constructed a ROC curve to identify an optimum IMA rule-out value. The IMA values (mean+/-SD) for the normals, non-converters, and converters were 89+/-7.1, 100+/-13.9, and 126+/-14.1 U/ml, respectively, and each mean was statistically different from the means of the other groups. The ROC curve comparing converters and non-converters showed an area of 0.89 (p <0.001) compared to the line of identity. An IMA cut-off of 97 U/ml gives a 98% sensitivity and 45% specificity and may be the best decision point to differentiate between these groups in our population. Nine of 78 non-converters were classified as having unstable angina. In conclusion, the ACB assay has a strong negative predictive value and sensitivity in our population for predicting the troponin results at 6 to 24 hr post-presentation. Because ACB results may be facility- and instrument-dependent, each facility should conduct an independent ROC analysis to determine the optimal IMA rule-out level. The ACB assay, when used in conjunction with cardiac injury markers and assessment of unstable angina, holds promise in reducing inappropriate low-risk hospital admissions and improving the clinical management of patients with chest pain.

Opiate toxicology testing is routinely performed in the hospital setting to identify abusers and/or to determine those patients who are not taking prescribed opiate analgesics such as oxycodone. Commercially available assays for opiate detection in urine have decreased sensitivity for oxycodone, which contributes to a high false-negative rate. Functioning as a beta site, our Veterans Affairs hospital evaluated a new enzyme immunoassay, DRI Oxycodone Assay, for its use in the qualitative and semiquantitative detection of oxycodone in urine. We hypothesize that an immunoassay for oxycodone with superior sensitivity and specificity, when compared to the traditional opiate assays, would reduce the need for more expensive and time-consuming confirmatory testing. We used the new liquid homogenous enzyme immunoassay to determine oxycodone results in a total of 148 urine samples from 4 different sample groups. Gas chromatography-mass spectroscopy was subsequently used to confirm the presence or absence of oxycodone (or its primary metabolite, noroxycodone). We also evaluated within-run, between-run, and linearity studies and conducted a crossover study to establish a cutoff value for oxycodone. In our patient population, we used the new DRI immunoassay to evaluate 17,069 urine samples to estimate oxycodone misuse profiles (patients not taking prescribed oxycodone or taking oxycodone without a prescription) during a 4-month period. The sensitivity and specificity of the new oxycodone immunoassay were 97.7% and 100%, respectively, at the cutoff concentration of 300 ng/mL. The assay linearity was 1,250 ng/mL, and the sensitivity was 10 ng/mL. Within-run precision and between-run coefficient of variation were 2.3% and 1.8%, respectively. None of the 15 compounds that we evaluated for interference had crossover significant enough to produce a positive oxycodone result when using 300 ng/mL as the cutoff value. None of the 17,069 oxycodone immunoassays was followed with a request for confirmation. Among patients with positive results (n = 224), 93 (41.5%) were not prescribed oxycodone. The new DRI Oxycodone Assay is a sensitive and specific screening test for the determination of oxycodone. The improved opiate screening results may lead to better patient and prescription management, to decreased laboratory spending, and to the identification of oxycodone abusers, which could result in decreased oxycodone-related mortality.

Objective: This paper compares nine strategies for determining hepatitis C antibody and viral status. They combine two tests for antibodies (enzyme immunoassays (EIA), recombinant immunoblot assays (RIBA)) and one for viremia (reverse transcription polymerase chain reaction (PCR)). Using optical density to divide EIA results into three categories (high positive, low positive, negative) was also considered., Methods: Decision analysis compared strategies on cost as well as sensitivity and specificity with regard to antibody and viral status. Parameters in the decision tree included antibody prevalence, proportion viremic, sensitivity, specificity, and cost of individual tests., Results: The two best strategies are EIA followed by PCR (EIA-->PCR); and EIA with three levels of optical density (EIA-OD), followed by RIBA for EIA-OD low positives, and then PCR for all positives (EIA-OD-->RIBA-->PCR). EIA-->PCR has equal viral sensitivity, slightly lower cost, slightly higher antibody sensitivity, but lower antibody specificity compared to EIA-OD-->RIBA-->PCR. The cost per false antibody positive avoided using EIA-OD-->RIBA-->PCR rather than EIA-->PCR is $36 when prevalence is 5%, and $193 when prevalence is 50%. Using EIA-OD-->RIBA-->PCR rather than EIA-->PCR results in 112 false antibody positives avoided for every true antibody positive missed when prevalence is 5%; this ratio is 18:1 when prevalence is 25%; and 6:1 when prevalence is 50%., Conclusions: EIA-OD-->RIBA-->PCR is the best choice when prevalence in the tested group is below 20%. As prevalence increases, the choice of EIA-OD-->RIBA-->PCR versus EIA-->PCR will depend on the relative importance of avoiding false antibody positives versus missing true antibody positives. Our analysis makes explicit the magnitude of this trade-off.

To test the hypothesis that micronutrient supplementation decreases genital HIV-1 shedding, a double-blind, randomized, placebo-controlled trial of 6 weeks of multivitamin plus selenium supplementation vs. placebo was conducted among 400 HIV-1-seropositive, nonpregnant, antiretroviral-naive women in Mombasa, Kenya. Primary outcome measures included cervical and vaginal shedding of HIV-1-infected cells and RNA. Secondary outcomes included plasma viral load and CD4 count. Surprisingly, the odds of detection of vaginal HIV-1-infected cells were 2.5-fold higher (P = 0.001) and the quantity of HIV-1 RNA in vaginal secretions was 0.37 log10 copies/swab higher (P = 0.004) among women who received micronutrients in comparison to placebo, even after adjustment for potential confounders including baseline HIV-1 shedding and CD4 count. The increase in vaginal HIV-1 shedding was greatest among women who had normal baseline selenium levels. Micronutrient supplementation resulted in higher CD4 (+23 cells/microL, P = 0.03) and CD8 (+74 cells/microL, P = 0.005) counts compared with placebo but did not alter the plasma viral load. In this randomized trial, micronutrients resulted in higher levels of genital HIV-1 shedding compared with placebo. The potential benefit of micronutrient supplementation in HIV-1-seropositive women should be considered in relation to the potential for increased infectivity.

Background: Serum retinol is the most commonly used indicator of vitamin A status. Retinol is transported in a 1-to-1 complex with retinol-binding protein (RBP). RBP is easy and inexpensive to measure, and studies have shown a high correlation between concentrations of RBP and concentrations of retinol. The performance of RBP in the context of infection or protein malnutrition, however, has not been evaluated., Objective: Our aim was to determine whether RBP is a good surrogate measure for retinol in the context of HIV-1 infection, protein malnutrition, and the acute phase response., Design: The relation between RBP and retinol was examined in a cross-sectional study of 600 Kenyan women., Results: There was a high correlation between concentrations of RBP and those of retinol (r = 0.88). When equimolar cutoffs were used, RBP predicted marginal vitamin A status (retinol < 1.05 micro mol/L) with 93% sensitivity and 75% specificity and vitamin A deficiency (retinol < 0.70 micro mol/L) with 91% sensitivity and 94% specificity. Similarly high sensitivities and specificities were found among subgroups with HIV-1 infection, a positive acute phase response, and protein malnutrition. Protein malnutrition and a positive acute phase response were common, especially among HIV-1-infected women, and were independently and synergistically associated with lower RBP concentrations., Conclusions: Equimolar RBP cutoffs predict vitamin A deficiency with high sensitivity and specificity, even in the context of infection and protein malnutrition. Like retinol, RBP may not accurately identify true vitamin A status under all conditions, because the acute phase response and protein malnutrition depress RBP concentrations. However, RBP may be a simple, inexpensive tool for assessment of vitamin A deficiency in population studies.

Among HIV-1-infected individuals, vitamin A deficiency has been associated with faster disease progression and greater infectivity in observational studies, but randomized clinical trials have shown no effect of vitamin A supplementation. We conducted a cross-sectional study of 400 HIV-1-infected and 200 HIV-1-uninfected women in Mombasa, Kenya to examine the relations between vitamin A deficiency (serum retinol <30 microg/dL) and HIV-1 status, HIV-1 disease stage, and the acute phase response (serum C-reactive protein >or=10 mg/L and/or alpha1-acid glycoprotein >or=1.2 g/L). Among the HIV-1-infected women, the effect of vitamin A supplementation was examined in a randomized trial. Vitamin A deficiency was independently associated with HIV-1 infection (OR = 2.7, 95% CI: 1.9-4.0) and the acute phase response (OR = 2.8, 95% CI: 1.9-4.1). Among HIV-1-infected women, vitamin A deficiency and the acute phase response were associated with each other and were both independently associated with higher HIV-1 plasma viral load and lower CD4 count. HIV-1-infected women having an acute phase response had no increase in serum vitamin A levels after supplementation. Serum levels increased significantly among women without an acute phase response, although not to normal levels among women who were deficient at baseline. Among HIV-1-infected individuals, it is likely that low serum vitamin A concentrations reflect more active infection and the acute phase response. These results provide possible explanations for the disparity between observational studies and randomized trials of vitamin A for HIV-1 infection.

Observational studies have associated vitamin A deficiency with vaginal shedding of human immunodeficiency virus (HIV) type 1-infected cells and mother-to-child HIV-1 transmission. To assess the effect of vitamin A supplementation on vaginal shedding of HIV-1, a randomized, double-blind, placebo-controlled trial of 6 weeks of daily oral vitamin A (10,000 IU of retinyl palmitate) was conducted among 400 HIV-1-infected women in Mombasa, Kenya. At follow-up, there was no statistically significant difference in the prevalence of HIV-1 DNA (18% vs. 21%, P=.4) or the quantity of HIV-1 RNA (3.12 vs. 3.00 log(10) copies/swab, P=1.0) in vaginal secretions of women receiving vitamin A, compared with women receiving placebo. No significant effect of supplementation on plasma HIV-1 load or CD4 or CD8 cell counts was observed, and no effect was seen among women who were vitamin A deficient at baseline. Vitamin A supplementation is unlikely to decrease the infectivity of women infected with HIV-1.

Homocysteine (tHcy) is a risk factor for atherosclerosis in patients with end-stage renal disease and chronic renal insufficiency (CRI). Vitamin B6 deficiency may result in high tHcy levels, especially after a methionine load (PML). Therefore, we evaluated vitamin B6 metabolism and tHcy (fasting and PML) levels in patients with CRI and those on hemodialysis (HD) therapy before and during high-dose sequential vitamin B6 and folic acid supplementation in male patients (27 patients, HD, 17 patients, CRI) and 19 age-matched healthy controls. Vitamin B6 doses were 100 mg/d in patients with CRI and 200 mg/d in HD patients, plus folic acid (5 mg/d), for more than 3 months in each period. We analyzed vitamin B6 metabolites by high-performance liquid chromatography in plasma and red blood cells (RBCs) and fasting tHcy in all cases and PML in subgroups of 11 HD patients and 14 patients with CRI. We found vitamin B6 deficiency and high tHcy (fasting and PML) levels in all patients. Plasma and RBC levels of pyridoxal and pyridoxal phosphate were abnormally low, whereas levels of pyridoxic acid (PA), an end product of vitamin B6 metabolism, were extremely high in both groups. Fasting and PML tHcy levels were partially resistant to vitamin B6 supplements, with different response patterns in HD patients and those with CRI. Thus, the PML defect was more responsive to folic acid in HD patients, whereas vitamin B6 partially reduced PML tHcy levels in patients with CRI. Resistance of tHcy to vitamin B6 treatment in patients with CRI and HD patients is not caused by poor absorption or low tissue stores. Rather, nonvitamin factors or potentially toxic PA levels may be implicated in abnormal vitamin B6 and/or tHcy metabolism during renal insufficiency., (Copyright 2002 by the National Kidney Foundation, Inc.)

Epidemiological studies have suggested that low levels of selenium are associated with a higher incidence of both lung and prostate cancer. We analyzed the selenium serum concentration in 356 Carotene and Retinol Efficacy Trial (CARET) participants who later developed lung cancer and 356 matched controls and in 235 prostate cancer cases and 456 matched controls. Serum samples were obtained a mean of 4.7 years before diagnosis for both tumor types. Controls were matched to cases by year of randomization, age, smoking status, treatment arm, exposure population (asbestos workers or cigarette smokers), and year of blood draw. In the control population (n = 820), significant predictors of low serum selenium concentration were current smoking status and East Coast locations of the study center. Overall, there was no significant difference in mean serum selenium in lung cancer cases versus controls (11.91 microg/dl versus 11.77 microg/dl) or prostate cancer cases versus controls (11.48 microg/dl versus 11.43 microg/dl). No statistically significant trend in odds ratio was seen across quartiles of serum selenium for lung cancer (P = 0.49) or prostate cancer (P = 0.69). In a subpopulation of 174 prostate cancer patients who had clinical and pathological staging material reviewed, there was no association between serum selenium and Gleason score or clinical or pathological stage. In the CARET population of current and former smokers consuming an ad libitum diet, the serum concentration of selenium was not a risk factor for either lung cancer or prostate cancer.

Objective: To assess the relation between selenium deficiency and vaginal or cervical shedding of HIV-1-infected cells., Design: Cross-sectional study of 318 HIV-1 seropositive women in Mombasa, Kenya., Methods: Vaginal and cervical swab specimens were tested for the presence of HIV-1 DNA by polymerase chain reaction. Multivariate logistic regression models, adjusting for CD4 count and vitamin A deficiency, were used., Results: Selenium deficiency (defined as levels <85 microg/L) was observed in 11% of the study population. In unstratified multivariate analyses, there was no significant association between selenium deficiency and vaginal or cervical shedding. In stratified analyses, however, significant associations became apparent after excluding women with predictors of shedding with strong local effects on the genital tract mucosa. Among women who did not use oral contraceptives and who did not have vaginal candidiasis, selenium deficiency was significantly associated with vaginal shedding (adjusted odds ratio [AOR] 2.9, 95% confidence interval [CI] 1.0--8.8, p =.05). Effect modification was also observed in the relation between selenium deficiency and cervical shedding, with a significant association seen among those women who were not using oral contraceptive pills or depot medroxyprogesterone acetate and who did not have Neisseria gonorrhoeae infection (AOR 2.8, 95% CI 1.1--7.0, p =.02)., Conclusions: We found selenium deficiency to be associated with a nearly threefold higher likelihood of genital mucosal shedding of HIV-1--infected cells, suggesting that deficiency may increase the infectiousness of women with HIV-1. Nutritional interventions to prevent HIV-1 transmission warrant investigation.

Preeclampsia is an important cause of maternal and perinatal mortality worldwide. The etiology of this relatively common medical complication of pregnancy, however, remains unknown. We studied the relationship between maternal leukocyte selenium, zinc, and copper concentrations and the risk of preeclampsia in a large hospital-based case-control study. One hundred seventy-one women with proteinuric pregnancy-induced hypertension (with or without seizures) comprised the case group. Controls were 184 normotensive pregnant women. Leukocytes were separated from blood samples collected during the patients' postpartum labor and delivery admission. Leukocyte concentrations for the three cations were measured by inductively coupled plasma-mass spectrometry (ICP-MS). Concentrations for each cation were reported as micrograms per gram of total protein. Women with preeclampsia had significantly higher median leukocyte selenium concentrations than normotensive controls (3.23 vs 2.80 microg/g total protein, p < 0.0001). Median leukocyte zinc concentrations were 31% higher in preeclamptics as compared with controls (179.15 vs 136.44 microg/g total protein, p < 0.0001). Although median leukocyte copper concentrations were slightly higher for cases than controls, this difference did not reach statistical significance (17.72 vs 17.00 microg/g total protein, p = 0.468). There was evidence of a linear increase in risk of preeclampsia with increasing concentrations of selenium and zinc. The relative risk for preeclampsia was 3.38 (adjusted odds ratio [OR] = 3.38, 95% confidence interval [CI] = 1.53-7.54) among women in the highest quartile of the control selenium distribution compared with women in the lowest quartile. The corresponding relative risk and 95% CI for preeclampsia was 5.30 (2.45-11.44) for women in the highest quartile of the control zinc distribution compared with women in the lowest quartile. There was no clear pattern of a linear trend in risk with increasing concentration of leukocyte copper concentrations (adjusted for linear trend in risk = 0.299). Our results are consistent with some previous reports. Prospective studies are needed to determine whether observed alterations in selenium and zinc concentrations precede preeclampsia or whether the differences may be attributed to preeclampsia-related alterations in maternal and fetal-placental trace metal metabolism.

Objectives: Prostate-specific antigen (PSA) is the most useful of all tumor markers. Although the sensitivity is impressive, low specificity results in a lack of cancer detection in a significant proportion of patients undergoing prostate biopsy. Several recent studies have addressed the need for improved specificity. Of all these approaches, the free/total PSA ratio appears to be the most promising. Given that most circulating PSA is complexed to alpha1-antichymotrypsin, and that this moiety represents a greater proportion of the total PSA in those men with carcinoma, we set out to determine whether complexed PSA would improve specificity in the detection of men with prostate cancer., Methods: Archival sera were obtained from 300 men, 75 of whom had biopsy-proved prostate cancer. All sera had been previously stored at -70 degrees C for variable periods. An investigative assay for complexed PSA (Bayer) was used. The Tandem-R free and total PSA assays (Hybritech) were used according to the manufacturer's recommendations., Results: Among all patients, specificities for the total PSA, free/total PSA, and complexed PSA alone were 21.8%, 15.6%, and 26.7%, respectively, at cutoffs yielding 95% sensitivity. Similar equivalence or superior performance, in terms of specificity relative to the free/total PSA ratio, was seen at other sensitivity thresholds and other total PSA ranges., Conclusions: Complexed PSA alone performs better than total PSA or the free/total PSA ratio and obviates the need for a second analyte determination. We believe this marker may offer significant enhancement in PSA testing with significant economic advantages.

Background: Consistency in prostate-specific antigen (PSA) quantitation by different PSA test manufacturers would minimize potential clinical confusion. The Ciba Corning ACS PSA2 calibration has been adjusted for alignment with a proposed international standard and clinical concordance with the Hybritech Tandem R assay. Herein we evaluate the clinical effectiveness of this recalibrated PSA test by comparing it with the IMx (Abbott Laboratories) and Tandem R (Hybritech) assays., Methods: Archival serum was used that had been stored at -70 degrees C from men who underwent ultrasound-guided prostate needle biopsy. Assays were run according to each manufacturer's specifications in singlicate on a single thaw., Results: The study included sera of 191 patients; 44 of the patients had carcinoma. There were 151 men with PSA (Tandem R) in the range of 0-10.0 ng/ml, 28 of whom had cancer. The correlation coefficients for Tandem R versus ACS, Tandem R versus IMx, and ACS versus IMx were 0.958, 0.955, 0.979 for benign patients and 0.960, 0.954, and 0.985 for those with cancer, respectively. The corresponding slopes were 1.029, 0.855, and 0.824 for men without and 1.044, 0.830, and 0.790, respectively, for those with malignancy., Conclusions: These data demonstrate substantial equivalence of the restandardized ACS assay and of the Hybritech method. Significant bias exists between these methods and the IMx assay with lower results being identified with the latter. These findings have significant implication, particularly in screening when results of an IMx assay are compared to other assays.

As aerobic creatures, normal living requires that not only are human beings exposed to oxygen but are dependent on oxygen. Humans have evolved mechanisms to cope with living in an aerobic environment; however, modern humans may be more exposed to oxidant stresses. Much indirect evidence implicates reactive oxygen species in diseases such as cancer and atherosclerosis. There are also other diseases that are influenced by oxidative balance, including the normal process of aging. Common environmental factors that could cause oxidative stress include a low intake of dietary antioxidants, a high intake of polyunsaturated fatty acids, and exposure to ozone, ionizing radiation, and cigarette smoke. The recent development of overall measures of oxidant status, such as breath pentane; highly sophisticated measures, such as electron spin resonance and specific measures of base damage to DNA by mass spectrometry; and other methods will allow much more specific data to be collected on the importance of reactive oxygen species in many disease states. Such measures can serve as end points for a variety of studies in experimental animals and humans that will allow for the testing of many potential prooxidant and antioxidant compounds. Other important evidence will be available soon from, for example, large scale chemoprevention trials that are currently under way. As an indicator of the increased interest in oxidant balance, several reference laboratories now have nutritional biochemistry sections that offer measurement of specific free-radical scavenging enzymes. These enzyme measures complement the more routinely available measurements of trace element and antioxidant nutrients.

Children with juvenile-onset multiple carboxylase deficiency lack biotinidase activity (biotinamide amidohydrolase, EC 3.5.1.12) in the liver and other tissues. Hence, little free biotin is metabolically available, resulting in seizures, acidosis, and serious neurological damage. As the absence of hepatic biotinidase activity is reflected in serum, assessment of biotinidase status can easily be made from a blood sample. A convenient qualitative procedure for screening infants has been employed in order to estimate serum levels of biotinidase in as little as 10 microliters of sample. This colorimetric procedure detects the formation of free p-aminobenzoate cleaved from the substrate, N-biotinyl-p-aminobenzoate at pH 6.0. The assay is easily performed and has a low incidence of false positive results. A kinetic assay for serum biotinidase has also been developed using biotinyl-p-nitroanilide (BpNA) as substrate. When 50 microliters of biotinidase positive serum was incubated with 0.2 mM BpNA in phosphate buffer at pH 6.0, an increase in absorbance was observed at 405 nm. The rate of change in absorbance was followed kinetically on the Roche Cobas BIO analyzer at 37 degrees C. Monitoring the increase in absorbance of para-nitroanilide every 60 seconds over 30 minutes demonstrated linearity from 10 to 30 minutes. In comparing results from this kinetic assay on 48 randomly selected sera with those obtained using a colorimetric procedure, a correlation coefficient of 0.85 was obtained. Several false positive results were observed in clearly lipemic sera.

We measured immunologically active (apo + holo) retinol-binding protein (RBP), vitamin A-carrying (holo) free RBP, and transthyretin-bound (TTR) holo-RBP in serum from 34 retrospective cases of fluctuating acute renal failure. All subjects had high serum creatinine concentrations caused by renal failure. Apo + holo, holo-TTR-RBP, and (especially) holo-free RBP all correlated poorly but significantly with serum creatinine concentration. Therefore, the use of any form of RBP to measure vitamin A status may be of limited value in subjects with high creatinine concentrations in serum. However, molecular-exclusion HPLC may be able to distinguish increases in RBP concentration associated with renal failure from those caused by altered vitamin A status, because renal failure causes abnormalities in the number and retention times of chromatographic peaks as well as their areas.

Retinol and retinyl esters are measured in serum or plasma samples by gradient, normal-phase, adsorption "high-performance" liquid chromatography, with ultraviolet detection at 325 nm. The four major circulating retinyl esters in humans (esters of palmitate, stearate, oleate, and linoleate) are coeluted as a single peak. Retinyl acetate is included as an internal standard, to correct for variable recovery. Retinol values so measured correlated well (r = 0.88) with those by a widely used reversed-phase chromatographic technique (Clin Chem 1983;29:708-12). The mean retinol concentration was 570 (SEM 17) micrograms/L and the mean for retinyl esters was 33 (SEM 4) micrograms/L as determined in samples from 88 fasting young adults. Concentrations of retinol in plasma as low as 50 micrograms/L can be detected in 100-microL samples, as can 10 micrograms of retinyl esters per liter. Using this method, we measured absorption of low doses of vitamin A, which may provide a more physiological approach to assessment of fat malabsorption. Additionally, the procedure proved useful for quickly screening for vitamin A toxicity. Major advantages include small sample size, direct injection of the extract ed sample without evaporation, rapid elution pattern, co-elution of major retinyl esters as a single peak, and low limit of detection.

Screening programs for late-onset, biotin-responsive, multiple carboxylase deficiency (LMCD) detect colormetrically the presence of biotinidase activity in dried samples of whole-blood spotted on filter-papers as used in the neonatal screening of phenylketonuria. A sensitive and stable qualitative technique is described using 10 microliter of serum that avoids problems associated with poor sample collection, improper drying of blood-spots and transient color development. The modified assay is timely and suitable for the clinical laboratory not involved in mass screening programs.

The effect of protein energy malnutrition (PEM) on retinal function was investigated in weanling Long-Evans rats fed a low protein (4.2%) diet. After 8 wk, plasma retinol levels were lower in low protein (LP) and growth-restricted (GR) groups than in ad libitum controls (P less than 0.05); however, ocular vitamin A concentration remained normal. Plasma taurine concentration was lower only in the LP group, while retinal taurine was lower in both LP and GR groups than in control groups. The dark-adapted electroretinogram (ERG) became abnormal (e.g., depressed a and b waves, P less than 0.05) in both LP and GR groups but was corrected by ad libitum feeding of the control diet for an additional 8 wk. In a second study, weanling LP rats were supplemented with 0.4% taurine, 0.4% methionine or 0.4% glycine. Although taurine supplementation maintained plasma and retinal taurine stores, ERGs remained abnormal with retinal sensitivity significantly lower than in unsupplemented LP rats. Thus, PEM produced abnormal ERGs independent of ocular vitamin A concentration and retinal taurine levels. The high dietary taurine fed to protein-malnourished rats caused further impairment of visual function but was not detrimental to control or pair-fed rats.

Changes in serum, hepatic, and ocular vitamin A levels were followed in 9-month-old Long Evans rats fed either a vitamin-A-free or vitamin-A-sufficient diet for up to 18 months. After 18 months, hepatic total vitamin A fell exponentially from 2542 +/- 433 to 48 +/- 12 micrograms/g wet weight, but these stores maintained normal serum retinol and ocular total vitamin A concentrations in vitamin-A-deprived rats. However, retinal dark-adaptation time, a functional indicator of photoreceptor integrity, was prolonged in elderly vitamin-A-deprived rats as compared to vitamin-A-sufficient controls (p less than 0.05). Aging appeared to be the most important factor that depressed the rate of dark adaptation, with vitamin A status having a secondary effect. The proportion of total ocular retinaldehyde decreased (p less than 0.05) and the concentration of retinyl ester increased (p less than 0.05) in the eyes of 27-month-old vitamin-A-deprived rats compared to age-matched vitamin-A-sufficient animals. Possible mechanisms of visual dysfunction include abnormal retinal rhodopsin recycling caused by a dependence on newly absorbed dietary vitamin A (e.g., chylomicron). Alternatively, in the vitamin-A-deprived rat, decreased hepatic oxidation of pentobarbital (used for electroretinographic anesthesia) could prolong retinal anesthetic exposure and either directly depress neural transmission or indirectly alter transmission by affecting rhodopsin recycling.

The effect of 17 beta-estradiol (E) on an osteoblast-like cell line, UMR106, was studied in vitro. The concentrations of transferrin and seven enzymes (gamma glutamyl transferase, alkaline phosphatase, acid phosphatase, lactate dehydrogenase, creatine kinase, alanine aminotransferase and aspartate aminotransferase) were measured in these cells after incubation in culture medium containing either E or the vehicle. E treatment increased five of the seven enzymes and increased the transferrin concentration in the UMR106 cells while simultaneously reducing the proliferation rates. 4-Hydroxytamoxifen, an estrogen antagonist, produced a mild estrogen agonist action on growth rates and enzyme concentrations in the UMR106 cells. When E was present simultaneously, the agonist properties of 4-hydroxytamoxifen were enhanced. These studies show that E enhanced activity of five enzymes and the transferrin content of UMR106 cells after a 2-day incubation. 4-Hydroxytamoxifen enhanced the E effect, illustrating that estrogen antagonists may manifest agonist or antagonist properties depending on the model. These results extend our previous observations showing a direct effect of E in vitro on osteoblast-like cells.

Serum retinol-binding protein (RBP), with a biological half-life of less than 12 h, is a useful indicator of liver or kidney dysfunction. An automated immunoturbidimetric assay for the measurement of RBP has been developed using the Cobas-BIO centrifugal analyser and commercially available materials. Serum samples with RBP concentrations as low as 3 mg/L were measured. Within-run and day-to-day imprecision were 3.7 and 5.7%, respectively. The reference range (mean +/- 2SD) for 51 adults was 17 to 61 mg/L. Slight haemolysis of serum (haemoglobin 10 g/L) resulted in an apparent 8% reduction of RBP with greater interference at higher haemoglobin concentrations. However, bilirubin in concentrations up to 0.15 g/L did not interfere with RBP measurements. There was good correlation between immunoturbidimetry and a commercial radial immunodiffusion method. Serum RBP concentrations were decreased in liver disease and increased in renal failure.

The serum fructosamine concentrations measured in 64 diabetic patients correlated (r = 0.73) with glycated hemoglobins (HbA1c). However, 23 percent of the diabetic patients had normal fructosamine and abnormal HbA1c levels. In order to determine whether or not the discrepant values were the result of recent glycemic regulation by the diabetic patient, fructosamine levels of patients suffering from diabetic ketoacidosis (along with beta-hydroxybutyrate levels) were closely monitored. It was shown that short term alterations (one to three days) in serum glucose did not significantly affect fructosamine levels. Therefore, disagreements between fructosamine and HbA1c are most likely due to longer term improvement in glucose control by the diabetic or the result of the higher imprecision of the HbA1c assay.