Perinatal deaths and low birthweight in an urban health centre in the Gambia: A prospective cohort study.

Perinatal deaths (stillbirths after 28 weeks gestation and early neonatal deaths) are rarely reported separately but are the deaths most closely associated with complications during pregnancy, birth and the first days of life. We conducted a prospective cohort study to report perinatal deaths, late neonatal deaths and low birthweight babies as they occur. This cohort of birth outcomes from The Gambia was conducted between 2012 and 2016 and followed 1611 women attending a government-supported health center from the first antenatal visit to 28 days post-delivery. The outcome of the pregnancy was known for 1372 women (85.2%) and included 20 stillbirths and 12 early neonatal deaths. Of 1252 singleton babies with known birthweight 85 weighed less than 2500g (6.8%). Using multivariate analysis it was shown that women who attended the antenatal clinic four times or more were less likely to have a low birthweight baby than women who attended less than four times, OR 0.47 (95% CI:0.273-0.799). We conclude that frequent visits to the antenatal clinic are associated with better outcomes.

Reprint - Bipolar vs. monopolar transurethral resection of the prostate for lower urinary tract symptoms secondary to benign prostatic obstruction: A Cochrane review.

INTRODUCTION: There remains uncertainty regarding the differences in patient outcomes between monopolar transurethral resection of the prostate (MTURP) and bipolar TURP (BTURP) in the management of lower urinary tract symptoms (LUTS) secondary to benign prostatic obstruction (BPO). METHODS: A systematic literature search was carried out up to March 19, 2019. Methods in the Cochrane Handbook were followed. Certainty of evidence (CoE) was assessed using the GRADE approach. RESULTS: A total of 59 randomized controlled trials (RCTs) with 8924 participants were included. BTURP probably results in little to no difference in International Prostate Symptom Score (IPSS) at 12 months (mean difference -0.24, 95% confidence internal [CI] -0.39--0.09; participants=2531; RCTs=16; moderate CoE) or health-related quality of life (HRQOL) at 12 months (mean difference -0.12, 95% CI -0.25-0.02; participants=2004, RCTs=11; moderate CoE), compared to MTURP. BTURP probably reduces TUR syndrome (relative risk [RR] 0.17, 95% CI 0.09-0.30; participants= 6,745, RCTs=44; moderate CoE) and blood transfusions (RR 0.42, 95% CI 0.30-0.59; participants=5727, RCTs=38; moderate CoE), compared to MTURP. BTURP may carry similar risk of urinary incontinence at 12 months (RR 0.20, 95% CI 0.01-4.06; participants=751; RCTs=4; low CoE), re-TURP (RR 1.02, 95% CI 0.44-2.40; participants=652, RCTs=6, I2=0%; low CoE) and erectile dysfunction (International Index of Erectile Function [IIEF-5]) at 12 months (mean difference 0.88, 95% CI -0.56-2.32; RCTs=3; moderate CoE), compared to MTURP. CONCLUSIONS: BTURP and MTURP probably improve urological symptoms to a similar degree. BTURP probably reduces TUR syndrome and blood transfusion slightly postoperatively. The moderate certainty of evidence available for primary outcomes suggests no need for further RCTs comparing BTURP and MTURP.

Determinants of compliance with the World Health Organisation recommendations for pregnant women in an urban health centre in The Gambia.

In 2001 the World Health Organization drew up recommendations for pregnant women in order to reduce maternal mortality: the first visit to the antenatal clinic to be in the first trimester, at least four visits in total and delivery with a trained birth attendant. This study reports the extent to which pregnant women attending a health centre in The Gambia complied with the recommendations. A cohort of 1611 consecutive pregnant women was recruited. Only 384 (23.9%) women first attended in the first trimester and 568 (41.6%) attended at least four times. Only 15.8% of the women complied with all recommendations. Following multivariate analysis the educational level of the partner was the sole factor associated with both recommendations regarding attendance. This level of compliance reflects widespread ignorance of the value of early antenatal care and frequent visits. Public health programmes require a basic level of education to be effective.

A core outcome set for localised prostate cancer effectiveness trials: protocol for a systematic review of the literature and stakeholder involvement through interviews and a Delphi survey.

BACKGROUND: Prostate cancer is a growing health problem worldwide. The management of localised prostate cancer is controversial. It is unclear which of several surgical, radiotherapeutic, ablative, and surveillance treatments is the most effective. All have cost, process and recovery, and morbidity implications which add to treatment decision-making complexity for patients and healthcare professionals. Evidence from randomised controlled trials (RCTs) is not optimal because of uncertainty as to what constitutes important outcomes. Another issue hampering evidence synthesis is heterogeneity of outcome definition, measurement, and reporting. This project aims to determine which outcomes are the most important to patients and healthcare professionals, and use these findings to recommend a standardised core outcome set for comparative effectiveness trials of treatments for localised prostate cancer, to optimise decision-making. METHODS/DESIGN: The range of potentially important outcomes and measures will be identified through systematic reviews of the literature and semi-structured interviews with patients. A consultation exercise involving representatives from two key stakeholder groups (patients and healthcare professionals) will ratify the list of outcomes to be entered into a three round Delphi study. The Delphi process will refine and prioritise the list of identified outcomes. A methodological substudy (nested RCT design) will also be undertaken. Participants will be randomised after round one of the Delphi study to one of three feedback groups, based on different feedback strategies, in order to explore the potential impact of feedback strategies on participant responses. This may assist the design of a future core outcome set and Delphi studies. Following the Delphi study, a final consensus meeting attended by representatives from both stakeholder groups will determine the final recommended core outcome set. DISCUSSION: This study will inform clinical practice and future trials of interventions of localised prostate cancer by standardising a core outcome set which should be considered in comparative effectiveness studies for localised prostate cancer.

Provision of cancer information as a "support for navigating the knowledge landscape": findings from a critical interpretive literature synthesis.

PURPOSE OF THE RESEARCH: Information is often seen as a crucial tool for the support of cancer patients, facilitating their involvement in care management and in decision-making. The importance of theory in guiding provision of cancer information has been widely accepted, but there is a growing need for critical reflection on the concepts underlying approaches to information provision. This paper presents findings from a critical review of literature related to information in cancer care. METHODS: Critical interpretive synthesis (CIS) was employed to review and synthesise published literature. 57 publications were selected in a multi-step systematic process. Their content was analysed and synthesised using established methodology consistent with primary qualitative research. KEY RESULTS: The synthesis identified and characterised a concept of cancer information provision as a "support for navigating the knowledge landscape". This concept recognises the diverse, changing and relational nature of patients' values, needs and preferences. It promotes a view of information provision as an ongoing and flexible process of navigating different resources, which in turn support the navigation of patients' broader experiences of their health and care. This process recognises various levels of patient involvement with healthcare services, and ensures timely provision of selected and personally relevant information. CONCLUSION: The concept of "support for navigating the knowledge landscape" offers a useful way of envisaging information services for people with cancer (and possibly also with other chronic illnesses), which would be responsive to patients' needs and preferences.

Defining a patient-reported outcome measure for urethral stricture surgery.

BACKGROUND: A systematic literature review did not identify a formally validated patient-reported outcome measure (PROM) for urethral stricture surgery. OBJECTIVE: Devise a PROM for urethral stricture surgery and evaluate its psychometric properties in a pilot study to determine suitability for wider implementation. DESIGN, SETTING, AND PARTICIPANTS: Constructs were identified from existing condition-specific and health-related quality of life (HRQoL) instruments. Men scheduled for urethroplasty were prospectively enrolled at five centres. INTERVENTION: Participants self-completed the draft PROM before and 6 mo after surgery. MEASUREMENTS: Question sets underwent psychometric assessment targeting criterion and content validity, test-retest reliability, internal consistency, acceptability, and responsiveness. RESULTS AND LIMITATIONS: A total of 85 men completed the preoperative PROM, with 49 also completing the postoperative PROM at a median of 146 d; and 31 the preoperative PROM twice at a median interval of 22 d for test-retest analysis. Expert opinion and patient feedback supported content validity. Excellent correlation between voiding symptom scores and maximum flow rate (r = -0.75), supported by parallel improvements in EQ-5D visual analogue and time trade-off scores, established criterion validity. Test-retest intraclass correlation coefficients ranged from 0.83 to 0.91 for the total voiding score and 0.93 for the construct overall; Cronbach's α was 0.80, ranging from 0.76 to 0.80 with any one item deleted. Item-total correlations ranged from 0.44 to 0.63. These values surpassed our predefined thresholds for item inclusion. Significant improvements in condition-specific and HRQoL components following urethroplasty demonstrated responsiveness to change (p < 0.0001). Wider implementation and review of the PROM will be required to establish generalisability across different disease states and for more complex interventions. CONCLUSIONS: This pilot study has defined a succinct, practical, and psychometrically robust PROM designed specifically to quantify changes in voiding symptoms and HRQoL following urethral stricture surgery.

Automated claim and payment verification.

Since the start of managed care, there has been steady deterioration in the ability of physicians, hospitals, payors, and patients to understand reimbursement and the contracts and payment policies that drive it. This lack of transparency has generated administrative costs, confusion, and mistrust. It is therefore essential that physicians, hospitals, and payors have rapid access to accurate information on contractual payment terms. This article summarizes problems with contract-based reimbursement and needed responses by medical practices. It describes an innovative, Internet-based claims and payment verification service, Phynance, which automatically verifies the accuracy of all claims and payments by payor, contract and line item. This service enables practices to know and apply the one, true, contractually obligated allowable. The article details implementation costs and processes and anticipated return on investment. The resulting transparency improves business processes throughout health care, increasing efficiency and lowering costs for physicians, hospitals, payors, employers--and patients.

Intestinal bioavailability and biotransformation of 3-hydroxybenzo(a)pyrene in an isolated perfused preparation from channel catfish, Ictalurus punctatus.

The intestinal bioavailability and biotransformation of 3-hydroxybenzo(a)pyrene, a major metabolite of benzo(a)pyrene in many animal species, was investigated in an in situ isolated intestinal preparation from the channel catfish, and in vitro with preparations of catfish intestine and blood. 3-Hydroxybenzo(a)pyrene was a good substrate for adenosine 3'-phosphate 5'-phosphosulfate (PAPS)-sulfotransferase and UDP-glucuronosyltransferase in cytosol or microsomes prepared from intestinal mucosa. The benzo(a)pyrene-3-glucuronide and 3-sulfate conjugates were only very slowly hydrolyzed by intestinal beta-glucuronidase and sulfatase. The K(m) values for PAPS-sulfotransferase and UDP-glucuronosyltransferase were 0.4 and 1 microM, respectively, and V(max) were 1.61 +/- 1.08 nmol benzo(a)pyrene-3-sulfate/min/mg of cytosolic protein and 1.08 +/- 0.54 nmol benzo(a)pyrene-3-glucuronide/min/mg of microsomal protein. Hydrolytic enzyme activities were three orders of magnitude slower. In the in situ intestinal preparation, [(3)H]3-hydroxybenzo(a)pyrene was readily metabolized to the glucuronide and sulfate conjugates. After 1 h of incubation of 2 or 20 microM [(3)H]3-hydroxybenzo(a)pyrene in the in situ preparation, the luminal contents contained 3-hydroxybenzo(a)pyrene, benzo(a)pyrene-3,6-dione, benzo(a)pyrene-3-sulfate, and benzo(a)pyrene-3-glucuronide. Mucosal samples contained these components, as well as some unextractable material. The blood contained mainly benzo(a)pyrene-3-sulfate and an as yet unidentified metabolite of 3-hydroxybenzo(a)pyrene bound to hemoglobin. Some, but not all, blood samples contained small amounts of 3-hydroxybenzo(a)pyrene, benzo(a)pyrene-3-glucuronide, and benzo(a)pyrene-3,6-dione. These studies demonstrate the rapid phase 2 conjugation of a phenolic benzo(a)pyrene metabolite in intestinal mucosa, and the transfer of the phase 2 sulfate and glucuronide conjugates to blood.

Oral bioavailability and pharmacokinetics of elimination of 9-hydroxybenzo[a]pyrene and its glucoside and sulfate conjugates after administration to male and female American lobsters, Homarus americanus.

The pharmacokinetics of [(3)H]-9-hydroxybenzo[a]pyrene (9-OH-BaP), a highly lipophilic primary metabolite of benzo(a)pyrene, were examined after intrapericardial (iv) or oral doses of 50 or 200 microg/kg to intermolt American lobsters, Homarus americanus. Combining data for all lobsters, the average terminal elimination half-life of parent 9-OH-BaP was 97.3 h after iv and 56.5 h after oral administration, considerably less than found previously for benzo(a)pyrene (720 h). The oral bioavailability of parent 9-OH-BaP, calculated from the area under the hemolymph concentration curve, was 15.9%. The low bioavailability and variable elimination rates were attributed to extensive first-pass conjugation and sequestration in the hepatopancreas. BaP-9-sulfate was the major metabolite. Hemolymph concentrations of BaP-9-sulfate increased up to one day after the dose, and then decreased, with a terminal elimination half-life of 45 h. BaP 9-beta-D-glucoside was a minor metabolite in most hemolymph and tissue samples; an exception was hemolymph from the iv high-dose group. Concentrations of 9-OH-BaP and metabolites in the edible muscle tissue were similar to those in hemolymph, and 9-OH-BaP residues at 10 to 16 days after the dose were 3 to 12 ng/g muscle. Sulfotransferase and UDP-glucosyltransferase (UGT) activities with 9-OH-BaP were found in the antennal gland, intestinal mucosa, and hepatopancreas (UGT only). Sulfatase activity with BaP-9-sulfate, found in both the hepatopancreas and the antennal gland, was thought to contribute to metabolite cycling. These studies showed that 9-OH-BaP was readily conjugated to sulfate and glucose in the lobster, and that despite their high lipophilicity, 9-OH-BaP and conjugates were excreted from the lobster hemolymph and tissues much more rapidly than benzo[a]pyrene.

Effect of micelle fatty acid composition and 3,4,3', 4'-tetrachlorobiphenyl (TCB) exposure on intestinal [(14)C]-TCB bioavailability and biotransformation in channel catfish in situ preparations.

Polychlorinated biphenyls are transferred in the diet along aquatic food chains. This study investigated the effect of dietary micelle composition and 3,4,3',4'-tetrachlorobiphenyl (TCB) exposure upon the subsequent systemic bioavailability and intestinal metabolism of [(14)C]-TCB in a catfish in situ intestinal preparation. Initial in vitro experiments examined the solubility of [(14)C]-TCB in micelles of varying fatty acid composition. Micelles composed of single fatty acids demonstrated greater [(14)C]-TCB solubility with those fatty acids of longer chain length. Similarly, micelles of the long-chain fatty acid, linoleic acid, solubilized more [(14)C]-TCB than mixed micelles formulated from equal amounts of myristic (14:0), palmitic (16:0), stearic (18:0), or linoleic (18:2) acids. Systemic bioavailability of [(14)C]-TCB (60 microM) from an in situ perfused intestinal preparation was 2.2-fold greater when delivered to the intestine in linoleic acid micelles as compared to the mixed micelle preparation. Catfish exposed in vivo to either 0.5 or 5.0 mg TCB/kg feed for 10 days resulted in a 45 to 47% decrease in the subsequent systemic bioavailability of [(14)C]-TCB in the in situ intestinal preparation. Total intestinal cytochrome P450 content was not significantly affected by TCB preexposure. Immunodetectable CYP1A was found only in the 5.0 mg TCB/kg diet treatment. Corresponding intestinal aryl hydrocarbon hydroxylase (AHH) activities were 2.46 +/- 1.16, 2.43 +/- 1.58, and 11.35 +/- 10.25 pmol/min/mg protein for the control, 0.5, and 5 mg TCB/kg diet groups, respectively. [(14)C]-TCB in the in situ preparation was metabolized to only a small degree upon a single pass through the intestinal mucosa of the catfish. High variability and low rates of metabolism precluded the association of the magnitude of metabolism with dietary TCB pretreatment. Analysis of tissue sample extracts demonstrated 4 minor peaks, 3 of which were tentatively identified by co-elution with standards as 2-OH-3,4,3',4'-TCB, 4-OH-3,5,3',4'-TCB, and 5-OH-3, 4,3',4'-TCB. A fourth remains unidentified. Histological changes in the intestine such as thinning of the submucosa and increased numbers of goblet cells were evident at the 5.0 mg TCB/kg diet dose. These results suggest that TCB intestinal bioavailability may be linked to micelle composition as well as TCB exposure history. Furthermore, single pass intestinal metabolism appears to be a minor contributor to the biotransformational modification of dietary TCB.

Purification and characterization of hepatic and intestinal phenol sulfotransferase with high affinity for benzo[a]pyrene phenols from channel catfish, Ictalurus punctatus.

Cytosol from channel catfish liver and intestinal mucosa has high sulfotransferase activity with low concentrations of 3-, 7-, or 9-hydroxybenzo[a]pyrene. To further investigate this conjugation pathway, sulfotransferase activity toward 9-hydroxybenzo[a]pyrene was isolated from catfish intestinal and hepatic cytosol by chromatography on anion exchange and PAP-agarose affinity columns. SDS-PAGE of the active fractions showed that one major band with molecular size of about 41,000 Da was isolated from intestine, while two bands of about 41,000 and 31,000 Da were obtained from liver. Antibodies against human phenol-sulfating sulfotransferase cross-reacted strongly with the 41,000-Da bands from liver and intestine, but weakly with the hepatic 31,000-Da protein. N-Terminal sequence information could not be obtained from the pure proteins. Following digestion, an internal sequence of 20 amino acid residues was obtained from the hepatic 41,000-Da protein, which matched a sequence found in several mammalian sulfotransferases. No fish sulfotransferase sequences were available for comparison. The identity of the hepatic 31,000-Da protein was not established. The purified 41,000-Da proteins had very high activities with 3-, 7-, or 9-hydroxybenzo[a]pyrene, with K(m) values in the 40-100 nM range and V(max) 125-300 nmol/min/mg of protein. Substrate inhibition was observed when the concentrations of hydroxylated benzo[a]pyrenes were above 0.5 microM. As well as benzo[a]pyrene phenols, the purified 41,000-Da sulfotransferases catalyzed sulfation of 2-naphthol, 4-nitrophenol, 4-methylumbelliferone, 7-(hydroxymethyl)-12-methylbenz[a]anthracene, dehydroepiandrosterone, estrone, and 17beta-estradiol. Phenolic compounds were the preferred substrates for the purified enzymes.

The influence of diet on the regional distribution of glutathione S-transferase activity in channel catfish intestine.

There is evidence that glutathione conjugates are the major metabolites formed following systemic uptake of carcinogenic contaminants from the intestine. The effect of commercial diet versus a semi-purified diet on the distribution of glutathione S-transferase (GST) activity was examined in proximal, medial, and distal sections of catfish intestine. The bulk of GST activity with 1-chloro-2,4-dinitrobenzene, ethacrynic acid, and 3H-benzo[a]pyrene-4,5-oxide, and the percent cytosolic protein cross-reacting with anti-catfish GST-pi were in the more proximal segments and dropped off distally in the two diet groups. However, the total GST-pi cross-reacting protein in the proximal section was significantly higher in fish fed a chow diet. Western blot analysis revealed pi-class GST to be expressed principally in the proximal intestine. Cytosol samples cross-reacted with antibodies to human GST-alpha, -mu, and -pi, but not -theta, classes. Alpha-like GST isoforms of MW 26,200 and 24,600, absent in sections from fish fed a purified diet, were differentially expressed only in the distal section of chow-fed fish. These results indicate that diet significantly elicits regional differences in GST protein levels, that components of the commercial chow affect GST protein expression in the distal intestine, and that maintenance diet should be taken into consideration during dietary exposure studies.

Sulfation and glucuronidation of benzo[a]pyrene-7,8-dihydrodiol in intestinal mucosa of channel catfish (Ictalurus punctatus).

Intestinal metabolism plays a significant role in the bioavailability of ingested environmental toxicants. In this study, the potential for first pass, phase 2 biotransformation of benzo[a]pyrene-7,8-dihydrodiol (BaP-7,8-diol) in intestinal mucosa was examined. Sulfotransferase and Uridine 5'-Diphospho-Glucuronyl-transferase activity were measured in cytosol, and microsomes respectively. Radiolabeled conjugation products were analyzed by TLC and high-performance liquid chromatography (HPLC). The results indicated that BaP-7,8-diol was a poor substrate for intestinal sulfotransferase. Vmax for the sulfation of BaP-7,8-diol was 0.002 nmol mg-1 min-1, which is at least three orders of magnitudes lower than the Vmax for phenolic BaP metabolites. Studies with 3'phosphoadenosine-5' phosphosulfate (PAP)-35S as co-substrate showed that an unidentified compound in the reaction mixture was sulfated, dependent on the BaP-7,8-diol concentration. This could indicate that BaP-7,8-diol was interacting with a regulatory site on the enzyme and stimulated sulfation of an endogenous molecule in cytosol. Kinetic analysis of microsomal glucuronidation resulted in a Vmax of 0.30 nmol mg-1 min-1 (+/- 0.06 S.D., n = 4), with a Km of 23.39 microM (+/- 2.66 S.D.). The Km for the co-substrate UDP-glucuronic acid was approximately 43 microM. The slow rates for sulfation and glucuronidation of BaP-7,8-diol may explain its relatively high systemic availability when ingested or produced by intestinal phase 1 enzymes.

Differential expression of alpha-like glutathione S-transferase (GST) isoforms in catfish intestine.

Previous studies suggested that dietary composition affected glutathione S-transferase (GST) activity in catfish intestine, and this activity varied along the intestine. In this study, catfish were fed a semi-purified diet or a commercial chow for at least 2 weeks. GST activity, percent protein cross-reacting with anti-catfish GST pi antibody, and immuno-cross-reactivity with antibodies specific for human alpha, mu, pi and theta class GSTs were determined in cytosol prepared from sections of proximal, medial, and distal intestine. The bulk of GST activity with 1-chloro-2,4-dinitrobenzene (CDNB) and ethacrynic acid, and the percent protein cross-reacting with anti-catfish GST pi were in the more proximal segments and dropped off distally in the two diet groups. The percent of cross-reacting GST protein in the proximal section of fish fed on commercial chow was significantly higher (4.3 +/- 1.7%) than in fish fed purified diet (2.3 +/- 0.2%). Further Western blot analysis revealed a differential expression of GST isoforms only in the distal segment of fish fed commercial chow that recognized human anti-alpha GST antibody. Distal intestinal segments of catfish exposed to 3,3',4,4'-tetrachlorobiphenyl (TCB) and beta-naphthoflavone (BNF) also revealed expression of distinct alpha-like GST isoforms. Results strongly suggest the distal segment as a site for potential biomarkers for polycyclic aromatic hydrocarbon (PAH)- and co-planar polychlorinated biphenyl (PCB)-type contaminants.

Inhibition of glutathione S-transferase zeta and tyrosine metabolism by dichloroacetate: a potential unifying mechanism for its altered biotransformation and toxicity.

Dichloroacetate (DCA) inhibits its own metabolism and is converted to glyoxylate by glutathione S-transferase zeta (GSTz). GSTz is identical to maleylacetoacetate isomerase, an enzyme of tyrosine catabolism that converts maleylacetoacetate (MAA) to fumarylacetoacetate and maleylacetone (MA) to fumarylacetone. MAA and MA are alkylating agents. Rats treated with DCA for up to five days had markedly decreased hepatic GSTz activity and increased urinary excretion of MA. When dialyzed cytosol obtained from human liver was incubated with DCA, GSTz activity was unaffected. In contrast, DCA incubation inhibited enzyme activity in dialyzed hepatic cytosol from rats. Incubation of either rat or human hepatic cytosol with MA led to a dose dependent inhibition of GSTz. These data indicate that humans or rodents exposed to DCA may accumulate MA and/or MAA which inhibit(s) GSTz and, consequently, DCA biotransformation. Moreover, DCA-induced inhibition of tyrosine catabolism may account for the toxicity of this xenobiotic in humans and other species.

Determination of chloral hydrate metabolites in human plasma by gas chromatography-mass spectrometry.

Chloral hydrate (CH) is a widely used sedative. Its pharmacological and toxicological effects are directly related to its metabolism. Prior investigations of CH metabolism have been limited by the lack of analytical techniques sufficiently sensitive to identify and quantify metabolites of CH in biological fluids. In this study a gas chromatography mass spectrometry (GC/MS) method was developed and validated for determining CH and its metabolites, monochloroacetate (MCA), dichloroacetate (DCA), trichloroacetate (TCA) and total trichloroethanol (free and glucuronidated form, TCE and TCE-Glu) in human plasma. Of these, DCA and MCA are newly identified metabolites in humans. The drug, its plasma metabolites and an internal standard, 4-chlorobutyric acid (CBA), were derivatized to their methyl esters by reacting with 12% boron trifluoride-methanol complex (12% BF3-MeOH). The reaction mixture was extracted with methylene chloride and analyzed by GC/MS, using a selected ion monitoring (SIM) mode. The quantitation limits of MCA, DCA, TCA, and TCE were between 0.12 and 7.83 microM. The coefficients of variation were between 0.58 and 14.58% and the bias values ranged between -10.03 and 14.37%. The coefficients of linear regression were between 0.9970 and 0.9996.

Pharmacokinetics and metabolism of [14C]dichloroacetate in male Sprague-Dawley rats. Identification of glycine conjugates, including hippurate, as urinary metabolites of dichloroacetate.

Pathways of metabolism of dichloroacetate (DCA), an investigational drug for the treatment of lactic acidosis in humans and a rodent hepatocarcinogen, are poorly understood. In this study, rats were given, by gavage, one or two 50 mg/kg doses of NaDCA. DCA labeled with 14C (carboxy carbon) or 13C (both carbons) was used in studies of disposition and pharmacokinetics, respectively. The effect of fasting for 14 hr before dosing was studied. Expired air, urine, feces, and tissues were collected from [14C]DCA-dosed rats. Urine was analyzed by HPLC, GC/MS, and NMR spectroscopy. Plasma samples were analyzed by GC/MS. DCA plasma elimination half-lives were 0.1 +/- 0.02 and 5.4 +/- 0.8 hr in young adult rats (180-265 g, 3-4 months of age) given one or two doses of DCA, respectively, and 9.7 +/- 1 hr in large, 16-month-old rats given two DCA doses. The percentage of the DCA dose excreted as CO2 varied from 17 to 46% and was lower (p < 0.001) in fed rats, compared with rats fasted overnight before dosing. Urine contained DCA and DCA metabolites, including oxalate, glyoxylate, and conjugated glycine (mainly hippurate and phenylacetylglycine). More unchanged DCA was excreted by large rats pretreated with DCA (mean, 20.2% of the dose) than by young adult rats given one dose of DCA (mean, 0.5%). This study confirmed that CO2, glycine, and oxalate are major products of DCA metabolism, it demonstrated that one dose of DCA altered the elimination of a subsequent dose, and it showed that age or body size, as well as access to food, significantly affected DCA metabolism in rats.