Asymptomatic bacteriuria in a multiracial workforce.

Prevalence of asymptomatic bacteriuria was determined in the first morning urine specimens from 5669 people who participated in a health screening survey of a local workforce. Higher age-standardized prevalences were observed in Maori women (18.0%), compared with Pacific Island women (9.

Field studies of aflatoxin exposure, metabolism and induction of genetic alterations in relation to HBV infection and hepatocellular carcinoma in The Gambia and Thailand.

The relative contribution of aflatoxins (AF) and hepatitis B virus (HBV) to the aetiology of liver cancer remains to be determined, as does the mechanism of any interaction between these two factors. Methods to measure individual exposure to AF permit the assessment of this possible interaction in field studies. The measurement of AF covalently bound to albumin in peripheral blood has been particularly useful in this respect.

Prognosis after recovery from myocardial infarction: the relative importance of cardiac dilatation and coronary stenoses.

In order to further define clinical and angiocardiographic predictors of long-term survival after myocardial infarction we followed 616 consecutive male patients under 60 years of age, survivors of a first (N = 455) or recurrent (N = 161) myocardial infarction, for 8.8 +/- 2.9 years.

A synthetic peptide inhibitor of human immunodeficiency virus replication: correlation between solution structure and viral inhibition.

A peptide designated DP-107 was synthesized containing amino acid residues 558-595 of the envelope glycoprotein gp160 of human immunodeficiency virus type 1 strain LAI (HIV-1LAI). Algorithms for secondary structure have predicted that this region of the envelope transmembrane protein should form an extended alpha-helix. Consistent with this prediction, analysis by circular dichroism (CD) indicated that, under physiological conditions, DP-107 is approximately 85% helical.

Accumulation of O6- and 7-methylguanine in DNA of N-nitroso-N-methylbenzylamine-treated rats is restricted to non-target organs for N-nitroso-N-methylbenzylamine-induced carcinogenesis.

The distribution and accumulation of O6-methylguanine (O6-meGua) and 7-methylguanine (7-meGua) was investigated immunocytochemically in target and non-target tissues of rats injected twice weekly with 0.5 mg N-nitroso-N-methylbenzylamine (NMBzA)/kg for 16.5 weeks.

Albuminuria in people at least 40 years old: effect of obesity, hypertension, and hyperlipidemia.

Concentrations of urinary albumin and the albumin:creatinine ratio were measured in early-morning urine specimens from 5670 people older than 40 years who participated in a health screening survey of a local workforce. Sex-specific reference intervals were determined in a subgroup of 3597 people after excluding 2073 individuals with Albustix-positive proteinuria; diabetes mellitus; bacteriuria; current hypertension; body mass index greater than or equal to 30 kg/m2; or serum triglyceride greater than or equal to 2.5 mmol/L.

Prospective, controlled, double-blind study of i.v. tenoxicam for analgesia after thoracotomy.

We have shown that a single i.v. dose of tenoxicam 20 mg, after thoracotomy, when compared with placebo in 20 patients (with one exclusion), was associated with a reduction in consumption of papaveretum, assessed by patient-controlled analgesia, of 2.

Aflatoxin exposure, malaria and hepatitis B infection in rural Gambian children.

Aflatoxin-albumin adduct levels were measured in serum samples obtained from a group of Gambian children. The relationships between exposure to aflatoxin and the prevalence of malaria, between exposure and humoral and cellular responses in vitro to defined malaria antigens and, amongst children with evidence of exposure to hepatitis B infection, between aflatoxin and carriage of the hepatitis B surface antigen (HBsAg), were assessed. Aflatoxin-albumin adduct was found in nearly all serum samples collected during a survey performed at the end of the dry season and levels of adduct were generally high (up to 720 pg aflatoxin-lysine equivalent/mg albumin).

Aflatoxin M1 in human breast milk from The Gambia, west Africa, quantified by combined monoclonal antibody immunoaffinity chromatography and HPLC.

Maternal to child exposure of aflatoxin M1 in breast milk is an underevaluated risk factor from dietary exposure to aflatoxin B1. A molecular dosimetry study in The Gambia, West Africa, was initiated to explore the relationships between dietary intake of aflatoxins during a 1 week period and a number of aflatoxin biomarkers including aflatoxin metabolite excretion into breast milk. For the breast milk study, five lactating women were identified and milk samples were collected by hand expression once a day during days 3-7 for three women and during days 3-6 for the two other women.

Characterization of the mcrBC region of Escherichia coli K-12 wild-type and mutant strains.

We have carried out an analysis of the Escherichia coli K-12 mcrBC locus in order to (1) elucidate its genetic organization, (2) to identify the proteins encoded by this region, and (3) to characterize their involvement in the restriction of DNA containing methylated cytosine residues. In vitro expression of recombinant plasmids carrying all or portions of the mcrBC region revealed that the mcrB and mcrC genes are organized as an operon. The mcrBC operon specifies five proteins, as evident from parallel in vitro and in in vivo expression studies.

Dietary intake of aflatoxins and the level of albumin-bound aflatoxin in peripheral blood in The Gambia, West Africa.

Aflatoxin is implicated as a risk factor for hepatocellular carcinoma in areas of the world with a high incidence of this tumor. The present study was designed to validate the use of aflatoxin-albumin adducts in peripheral blood as a measure of individual exposure to this carcinogen. Dietary intake of aflatoxin was measured at the individual level in 20 residents of Keneba, West Kiang, The Gambia, over a 7-day period and correlated with the level of aflatoxin bound to peripheral blood albumin at the beginning and end of the study.

Molecular dosimetry of aflatoxin-N7-guanine in human urine obtained in The Gambia, West Africa.

Hepatocellular carcinoma is one of the major human cancers, causing at least 250,000 deaths each year. Two of the major risk factors for this disease are aflatoxin exposure and hepatitis B virus. This study was undertaken to explore the relationship between dietary exposure to aflatoxins and the excretion of the major aflatoxin-DNA adduct and other metabolites into the urine of chronically exposed people who were either hepatitis B virus surface antigen-positive or -negative.

First-time coronary artery bypass grafting: the anaesthetist as a risk factor.

We have investigated the contribution of the anaesthetist and surgeon to outcome after 1301 consecutive coronary artery bypass grafting operations (first operation). The mean + 1 SD aspartate amino transferase concentration on the day after surgery (AST-D1) was 134 u litre-1 (or, after logarithmic transformation, 94 u litre-1). Twenty patients were selected at random from each of three groups having AST-D1 less than 100 u litre-1, 100-134 u litre-1 or greater than 134 u litre-1; positive ECG diagnoses of perioperative myocardial infarction were significantly more frequent with AST-D1 values greater than 100 u litre-1 than with smaller values, but no more frequent with AST-D1 greater than 134 u litre-1.

Aflatoxins isolated by immunoaffinity chromatography from foods consumed in The Gambia, West Africa.

An aflatoxin-specific, monoclonal antibody-based immunoaffinity chromatography method has been developed for the rapid isolation of aflatoxins from human foods. Aflatoxins were isolated by immunoaffinity chromatography from a variety of cooked foods, including maize, rice, millets, groundnut sauces, and leaf sauces, collected in The Gambia, West Africa. The aflatoxins were measured by direct fluorescence or high-pressure liquid chromatography.

Lack of effects of selenium on N-nitrosomethylbenzylamine-induced tumorigenesis, DNA methylation, and oncogene expression in rats and mice.

The effects of dietary selenium deficiency and excess on N-nitrosomethylbenzylamine-(NMBA) induced esophageal neoplasia in rats and forestomach tumors in mice and the effects of dietary selenium on DNA adduct formation and on the activities of DNA adduct-repairing enzyme and oncogene expression in rat esophagus were investigated. The esophageal and forestomach tumors were induced by administration of NMBA by gavage with a total dose of 39 mg/kg body wt in rats and 12 mg/kg body wt in mice. Neither selenium dietary deficiency (Se < 0.

The role of infection by Opisthorchis viverrini, hepatitis B virus, and aflatoxin exposure in the etiology of liver cancer in Thailand. A correlation study.

The incidence of the two principle types of liver cancer (hepatocellular carcinoma and cholangiocarcinoma) in five different areas of Thailand was compared with the prevalence of exposure to the main risk factors in samples of the population. Cholangiocarcinoma showed striking variations in incidence, which correlated closely with markers of exposure to the liver fluke, Opisthorchis viverrini. However, there was little geographic variation in incidence of hepatocellular carcinoma or in prevalence of the major risk factors (chronic carriage of hepatitis B virus and exposure to aflatoxin), and apparently there was little relationship between them.

Immunocytochemical localization of DNA adducts induced by a single dose of N-nitroso-N-methylbenzylamine in target and non-target tissues of tumor formation in the rat.

The formation and short-term persistence of O6-methylguanine (O6-meGua) and 7-methylguanine (7-meGua) in individual cells of various target and non-target tissues for tumor induction in rats were examined after a single dose of N-nitroso-N-methylbenzylamine (NMBzA). In the principal target organ, the esophagus, both adducts were observed at 6 h after 0.5, 1.

Liver cancer in Thailand. II. A case-control study of hepatocellular carcinoma.

Potential risk factors for hepatocellular carcinoma were investigated in a case-control study among inhabitants of north east Thailand. Sixty-five cases from 3 hospitals, with matched controls, were included. Infection with hepatitis-B virus was the major risk factor-chronic carriers of HB surface antigen had an estimated relative risk of 15.

Liver cancer in Thailand. I. A case-control study of cholangiocarcinoma.

Potential risk factors for cholangiocarcinoma were investigated in a case-control study among inhabitants of north-east Thailand, which included 103 cases from 3 hospitals, with age- and sex-matched controls. A clear association with past or present infection with Opisthorchis viverrini, as indicated by raised serum antibodies, was found (o.r.

Immunohistochemical detection of DNA alkylation adducts in rat and hamster liver after treatment with dimethylnitrosamine.

Monoclonal and polyclonal antibodies specific for methylation adducts have been applied in an immunohistochemical study of DNA damage in rat and hamster liver following exposure to dimethylnitrosamine. The approach was validated, for frozen and paraffin-embedded sections, by comparison with biochemical data on adduct levels in whole tissues or specific cell populations in the same experimental systems. The potential application of this method to human exposure assessment is discussed.

Identification of an aflatoxin G1-serum albumin adduct and its relevance to the measurement of human exposure to aflatoxins.

A major aflatoxin G1 (AFG1)-albumin adduct has been identified and characterized in rats following exposure to AFG1. The product isolated from a Pronase digest of in vivo-modified albumin was identical by chromatographic retention time to the synthetic product obtained by the acylase-catalysed deacetylation product of N alpha-acetyl-L-lysine with 8,9-dihydro-8,9-dibromo-AFG1. The in vitro product, AFG1-lysine, was characterized by UV, fluorescence, 1H- and 13C-NMR spectroscopy and fast atom bombardment MS.