Purification and properties of Drosophila heat shock activator protein

Drosophila heat shock activator protein, a rare transacting factor which is induced upon heat shock to bind specifically to the heat shock regulatory sequence in vivo, has been purified from shocked cells to more than 95 percent homogeneity by sequence-specific duplex oligonucleotide affinity chromatography. The purified protein has a relative molecular mass of 110 kilodaltons, binds to the regulatory sequence with great affinity and specificity, and strongly stimulates transcription of the Drosophila hsp70 gene. Studies with this regulatory protein should lead to an understanding of the biochemical pathway underlying the heat shock phenomenon.

Alpha-acetoxy derivatives of methyl-2-oxopropylnitrosamine: synthesis, hydrolysis rate and bacterial mutagenicity

N-Methyl-N-2-oxopropylnitrosamine (MOP) induces pancreatic tumors in hamsters. As models for the putative proximate carcinogenic alpha-hydroxy derivatives, we studied N-acetoxymethyl-N-2-oxopropylnitrosamine (AMOP) and N-methyl-N-(1-acetoxy-2-oxopropyl)nitrosamine (MAOP). AMOP was synthesized from aminoacetone by the method of Roller et al. [1975), Tetrahedron Lett., 25, 2065-2068) and MAOP was synthesized by acetoxylation of MOP with lead tetraacetate. The half-lives of AMOP, MAOP and acetoxymethylmethylnitrosamine (ADMN) in aqueous buffer decreased as the pH rose from 5 to 9, with values at pH 5 of 2.8 X 10(4) min for AMOP, 3.2 X 10(3) min for ADMN, and 23 min for MAOP. Mutagenicity was examined in Salmonella typhimurium TA1535, using a pre-incubation at pH 5 without microsomal activation. The mutagenic potency, expressed as revertants/mumole, was 56 for AMOP, 150 for ADMN, and 4.5 X 10(4) for MAOP. Hence, hydrolysis rates at pH 5 were probably important in determining the relative mutagenicity.

Prenatal sonographic assessment of the fetal thorax: normal values

Fetal thoracic circumference and thoracic length measurements were obtained by ultrasonographic examination on 576 women between 16 and 40 weeks gestation. Nomograms for thoracic circumference and thoracic length with respect to gestational age were developed. Growth of both thoracic parameters was observed to be linear throughout gestation. In normal pregnancy the ratios of thoracic circumference to abdominal circumference and thoracic length to humerus length remained virtually constant at 0.89 and 0.93, respectively.

Use of the objective structured clinical examination for assessment of vocational trainees for general practice

General practice training schemes currently have no structured methods of assessment and most rely on a variety of subjective ratings of performance. In West Cumbria the ;objective structured clinical examination' has been used to assess training performance in areas covered by small group teaching during the preceding terms. Consultation skills, interpretation of clinical data and a number of aspects of practice management were tested. The examination was conducted in the local postgraduate centre and assessed 20 trainees. Each trainee received feedback of his performance on each problem set and also an overall comparison with his peers.This method of assessment appeared to be well received by trainees and was practicable within the limited resources available. In addition, the variety of problems set allowed for a broad range of trainees' performances to be assessed.

An improved spectrophotometric assay for leucine aminopeptidase

A sensitive assay to determine the activity of leucine aminopeptidase (EC 3.4.11.1), using L-leucine thiobenzyl ester as substrate, was developed. Hydrolysis of the ester by leucine aminopeptidase can be monitored in the presence of 5,5-dithiobis-(2-nitrobenzoic acid) by continuous spectrophotometric measurement at 412 nm. Comparison with some amide substrates showed that the thiol ester provides a much more sensitive assay, its specificity constant (Vmax./Km) being some 3000-fold higher than that of leucine p-nitroanilide.

The Massachusetts program for reducing the risk of formaldehyde exposure

Urea formaldehyde foam insulation in homes has caused increasing concerns about the adverse health effects associated with residential exposure to formaldehyde emissions. These health effects cover a broad spectrum of symptoms, including neurophysiological effects, respiratory irritations, and eye and skin irritations. Recent studies have also suggested a possible correlation between exposure to formaldehyde vapors and cancer. In 1979, following hundreds of complaints of adverse health effects from occupants of dwellings insulated with urea formaldehyde foam insulation (UFFI), the Massachusetts Department of Public Health issued regulations banning the new installation of UFFI in Massachusetts. New State legislation was adopted in 1986 which reformulated UFFI policy. The law established a minimum concentration of formaldehyde of 0.1 parts per million (ppm) below which removal of the insulation is not required or encouraged. A trust fund financed by industry was established to pay for air testing and for the removal of UFFI from homes if the formaldehyde level exceeds the statutory minimum of 0.1 ppm or if an occupant experiences adverse health effects attributable to the insulation. Based on the Massachusetts experience, these requirements have been identified: the need for flexibility and midcourse corrections in the development of health policy to allow for the incorporation of new scientific information or changes in the economic or political environment, the need for close coordination with all affected parties, and the need for scientific and technical policy development to be joined with economic and political perspectives to ensure smooth implementation of health policies.

The synthesis of peptidylfluoromethanes and their properties as inhibitors of serine proteinases and cysteine proteinases

A synthesis of peptidylfluoromethanes is described that utilizes the conversion of phthaloyl amino acids into their fluoromethane derivatives. These can be deblocked and elongated. The inactivation of chymotrypsin by Cbz-Phe-CH2F (benzyloxycarbonylphenylalanylfluoromethane) was found to be considerably slower than that of the analogous chloromethane. The fluoromethane analogue inactivates chymotrypsin with an overall rate constant that is 2% of that observed for the inactivation of the enzyme with the chloromethane. However, the result is the same. The reagent complexes in a substrate-like manner, with Ki = 1.4 X 10(-4) M, and alkylates the active-centre histidine residue. Cbz-Phe-Phe-CH2F and Cbz-Phe-Ala-CH2F were investigated as inactivators of the cysteine proteinase cathepsin B. The difference in reactivity between fluoromethyl ketones and chloromethyl ketones is less pronounced in the case of the cysteine proteinase than for the serine proteinase. Covalent bond formation takes place in this case also, as demonstrated by the use of a radiolabelled reagent.

Competitive inhibition of human skin collagenase by N-benzyloxycarbonyl-L-prolyl-L-alanyl-3-amino-2-oxopropyl-L-leucyl-L- alanylglycine ethyl ester

A 'ketomethylene' peptide, N-benzyloxycarbonyl-L-prolyl-L-alanyl-3-amino- 2-oxopropyl-L-leucyl-L-alanylglycine ethyl ester, was synthesized and shown to be a fairly potent competitive inhibitor of human skin collagenase.

Anti-mutagenesis and anti-promotion by apigenin, robinetin and indole-3-carbinol

We assessed the anti-mutagenic and anti-promotion properties of two flavones, apigenin and robinetin, and of indole-3-carbinol, because these compounds have been reported in vegetables, the consumption of which has been associated with reduced rates of cancer. However, the active components of these foods and their effects on carcinogenesis have not been established. Anti-mutagenicity was determined in the Salmonella typhimurium assay by measuring the effects of the test compounds on bacterial mutagenesis induced by methyl-nitrosourea (MNU), methyl-n-nitro-N-nitrosoguanidine (MNNG), benzo[a]pyrene (BaP) or 2-aminoanthracene (2-AA). Inclusion of apigenin resulted in a 62% and a 43% inhibition of mutagenicity with 13 nmol of 2-AA and 30 nmol BaP respectively. Robinetin caused an 87% inhibition of mutagenicity by 2-AA, but indole-3-carbinol had little or no effect on the mutagenicity of any of the compounds. None of the three compounds inhibited mutagenesis by MNU or MNNG and none were mutagenic or toxic when tested in the absence of mutagenic compounds at doses up to 20 micrograms/plate. Anti-promotion properties were assessed by measuring the effects of apigenin, robinetin and indole-3-carbinol on induction of ornithine decarboxylase activity (ODC) in mouse epidermis by 17 nmol 12-O-tetradecanoyl phorbol-13-acetate (TPA). Pretreatment of the skin half an hour before TPA with apigenin, robinetin, butylated hydroxyanisole, 13-cis-retinoic acid (all at 50 mumol) or di-fluoromethylornithine (1.6 mumol) inhibited ODC induction at 6 h after TPA by 67-80%. Pretreatment with 50 mumol indole-3-carbinol caused a 78% elevation in the TPA induction at this time. Dose response measurements were conducted with apigenin, indole-3-carbinol and robinetin. Inhibition by 30-90% of TPA-induced ODC was observed at 6 h after TPA in mice pretreated with 12.5-100 mumol apigenin. Pretreatment with 37.5 or 50 mumol indole-3-carbinol or 0.5, 12.5 or 25 mumol robinetin resulted in elevated induction of epidermal ODC by TPA at 6 h after TPA. However, treatment with 50 or 100 mumol robinetin diminished ODC induction at 6 h after TPA. Treatment with 100 mumol apigenin or 50 or 100 mumol indole-3-carbinol in non-TPA-treated mouse skin caused elevations in epidermal ODC. In comparing the time course of ODC induction, indole-3-carbinol (50 mumol) pretreatment shifted the induction of epidermal ODC to earlier times, in addition to elevating ODC induction by TPA.(ABSTRACT TRUNCATED AT 400 WORDS)

The reemergence of smokeless tobacco

Smokeless tobacco (snuff and chewing tobacco) is reemerging as a popular form of tobacco, particularly among male adolescents. In different regions of the United States, from 8 to 36 percent of male high-school students are regular users. The use of smokeless tobacco has been shown to cause oral-pharyngeal cancer. The strongest link is with cancers of the cheek and gum. White mucosal lesions (leukoplakia) are found in 18 to 64 percent of users, often at the site where the tobacco was held. Other associations have been suggested for cancers of the esophagus, larynx, and pancreas. Nitrosamines, found in high concentrations in smokeless tobacco, most likely have a role in its carcinogenicity. Other health problems include periodontal disease, acute elevations of blood pressure, and dependence. In early 1986, after action at the state level, Congress enacted a federal law requiring health-warning labels on packages of smokeless tobacco and a ban on electronic advertising. Other regulatory measures under consideration include raising state and federal excise taxes, tightening controls on advertising, and prohibiting sales to minors. In view of the recent growth of this problem, policy makers are taking the opportunity to intervene with preventive measures to protect a new generation of tobacco users.

Massachusetts' approach to the prevention of heart disease, cancer, and stroke

Heart disease, cancer, and cerebrovascular disease together cause more than two out of three deaths in the United States annually. These three diseases are largely a result of widespread risk factors such as smoking, unhealthy diet, high blood pressure, physical inactivity, and environmental toxic exposure. The prevalence of these risk factors can be significantly lowered, resulting in major reductions in mortality rates for these diseases. Thus far, there have been no statewide disease prevention efforts to reduce deaths from all three diseases simultaneously. The Massachusetts Department of Public Health recently began an aggressive statewide program to prevent deaths from these three causes through a reduction in their underlying risk factors. Within 5 years, this program will save at least 2,000 lives annually. Similar efforts by public health agencies and health care practitioners in the rest of the United States could save many thousands of lives.

The present role of the local health department in environmental toxicology

Environmental health concerns are focusing sharply on health risks associated with exposure to toxic substances. The local health department role in responding to these concerns is becoming more crucial as well as more difficult. Commercial production of toxic chemicals is increasing rapidly. Individuals are being exposed to these substances in their residential communities as well as in their workplaces. Over two dozen major federal laws exercise some control over toxic substances, but much responsibility for implementation rests at the local level. Local health department responsibility is primarily in the areas of education, services, and regulation. Education must be provided for local government officials and for those who render and receive local environmental services. Services must include surveillance to identify environmental causes of disease, documentation of disease and dysfunctions possibly related to toxic substances, and coordination of environmental toxicology services with related community activities. Regulatory activities call for careful risk assessment and risk management, accomplished in cooperation with other government agencies, universities, and industry.

Evaluation of inhibitor constants and alkylation rates for a series of thrombin affinity labels

The kinetics for the inactivation of thrombin (EC 3.4.21.5) by a series of peptides containing C-terminal arginyl chloromethane in the presence of substrate were determined. The inhibitor effectiveness was analysed so as to allow for both the evaluation of the affinity with which the enzyme binds the inhibitor before irreversible modification and also the rate of covalent-bond formation between enzyme and inhibitor. The results obtained show that the observed large range in inhibitor effectiveness can be accounted for almost entirely by marked differences in affinity, with only small variations in rates of formation of covalent complex.

The Occupational Safety and Health Act. The national policy for the prevention of work-related illness

Occupational health and safety issues are increasingly important on the broader health agendas of both industrial and non-industrial communities. These issues go beyond traditional industrial hygiene into areas of environmental epidemiology and public health engineering. The policy framework for addressing such issues is the Occupational Safety and Health Act of 1970.

The irreversible inhibition of urokinase, kidney-cell plasminogen activator, plasmin and beta-trypsin by 1-(N-6-amino-n-hexyl)carbamoylimidazole

1-(N-Amino-n-hexyl)carbamoylimidazole hydrochloride was synthesized and shown to be a potent irreversible inhibitor of human urokinase (EC 3.4.21.31), pig kidney-cell plasminogen activator (EC 3.4.21.-), human plasmin (EC 3.4.21.7) and bovine pancreatic beta-trypsin (EC 3.4.21.4). The kinetics of inhibition of the enzymes were determined by monitoring the hydrolysis of an appropriate fluorogenic substrate. Bovine thrombin and Factor Xa are hardly affected by the inhibitor.

Tumorigenicity and mutagenicity studies with capsaicin of hot peppers

Capsaicin, the pungent principle of hot pepper, was administered at concentrations of 1, 0.5, 0.25, 0.125 and 0.0625% in powdered diet for 35 days to five groups of Swiss albino mice. In the capsaicin-treated groups 4 mice (10%) developed 4 adenocarcinomas of the duodenum (one tumor at each dose level, except for the highest dose), while no such tumor occurred in the untreated control mice. Capsaicin exhibited a low level of mutagenicity in the Ames assay with S. typhimurium strain TA98 in the presence of liver activating enzymes from Aroclor-induced rats.

The behaviour of urokinase and porcine kidney cell plasminogen activator towards some synthetic peptides

The behaviour of human urokinase and porcine kidney cell plasminogen activator towards some synthetic substrates has been investigated. Although N- benzyloxycarbonylglycylglycyl -L-arginine 4-methyl-7- coumarylamide (Z-Gly-Gly-Arg-Amc) (I), glutaryl-Gly-Arg-Amc (II) and Z-Gly-Gly-Arg-Val-OMe (III) were substrates, Boc-Gly-Gly-Arg-Val-Val-Gly-Gly-OEt (IV) and Z-Ala-Pro-Gly-Arg-Val-Val-Gly-Gly-OEt (V) were neither substrates nor inhibitors. Steady-state kinetic parameters for the hydrolysis of (II) and (III) by urokinase and porcine kidney cell plasminogen activator were similar.

Data sources for estimating environment-related diseases

Relating current morbidity and mortality to environmental and occupational factors requires information on parameters of environmental exposure for practitioners of medicine and other health scientists. A fundamental source of that information is the exposure history recorded in hospitals, clinics, and other points of entry to the health care system. The qualitative and quantitative aspects of this issue are reviewed.

The relevance of occupational medicine

As the burden-of-illness profile has shifted significantly in recent years, more attention is focused on occupational factors in disease, not only because of past developments and future aspects but mainly because of the numerous practical and theoretical implications and the involvement of many medical and social features.

First-pass radionuclide angiocardiography in the determination of left-to-right cardiac shunt site in children

To ascertain if the level of a left-to-right cardiac shunt can be reliably established by first-pass radionuclide angiocardiography with 99mTc-pertechnetate, 102 children have been studied; 19 without a shunt, 26 with an atrial septal defect (ASD), 45 with a ventricular septal defect (VSD), and 12 with a patent ductus arteriosus (PDA). Time-activity curves were generated over the right atrium and ventricle, and several quantitative parameters were derived from the curves. It was concluded that in the absence of right-sided valvular incompetence, the time-activity curves show the greatest abnormality in the cardiac chambers distal to the left-to-right shunt. The right ventricular curve is typically altered in ASD but cannot be relied upon to differentiate VSD or PDA. The identification of ASD is assisted by the use of two of the parameters, the count ratio C4:C1 and time ratio T2-T1.

Occupational exposure to aromatic amines: benzidine and benzidine-based dyes

Large-scale production of aromatic amines that serve as intermediates in the aniline dye industry began in this country during World War I. In the United States, the first known occupationally induced aromatic amine cancers of the bladder were observed at a dye factory in 1931. Additional cases of benzidine-related bladder cancer was subsequently reported at this same facility and at numerous other dye works in this country and throughout the world. In 1974, the Occupational Safety and Health Administration promulgated a standard to control the production and use of benzidine in the workplace. Although hazards associated with benzidine exposure have been reduced, a carcinogenic risk due to benzidine-based dye exposure is now apparent. In addition, several dyes produced from o-tolidine and o-dianisidine, carcinogenic compounds structurally related to benzidine, have demonstrated metabolism to their respective parent compounds. The history of occupational bladder cancer in the United States is traced and measures taken by the Occupational Safety and Health Administration to reduce exposure to this hazard are described.

The relationship between psychological factors and blood glucose regulation in insulin-dependent diabetic adolescents

Fifty-two insulin-dependent diabetic, white, rural, middle-class adolescent subjects who had diabetes 5 or more years participated in a project comparing psychological and personality variables to the degree of altered blood glucose regulation as measured by hemoglobin A1c (HbA1c) levels. An HbA1c level of 9.5% was arbitrarily chosen as a cutoff score to divide subjects into two groups: those having "adequate" (N = 25) and those having "inadequate" (N = 27) blood glucose regulation. There were no significant differences between high and low HbA1c groups for all psychological variables tested, i.e., anxiety, locus of control, self-concept, and various personality traits measured by the High School Personality Questionnaire (HSPQ). Female subjects scored significantly higher on the anxiety scale and had significantly higher HbA1c values and weight percentiles compared with male subjects. Six self-report diabetes questionnaires dealing with various aspects of diabetes care and adjustment were completed by mothers and five similar questionnaires were completed by the adolescents. There were no significant differences in the mean scores of the 11 diabetes questionnaires between the high and low HbA1c groups. Girls scored significantly higher than boys in "self-care" and on individual items pertaining to dysphoric feelings about diabetes. Our findings may have resulted from the homogeneity of the sample, but underlying metabolic and genetic factors need to be considered in differentiating subjects according to the level of blood glucose regulation.

A prospective study of symptomatic hypoglycemia in young diabetic patients

The frequency of symptomatic hypoglycemia was determined prospectively over an 18-mo period in 147 children and adolescents with diabetes mellitus. All patients were treated with two daily injections of insulin. The data were analyzed to determine the relationship between episodes of symptomatic hypoglycemia and blood glucose control as assessed by hemoglobin A1c measurements. There were 542 patient visits during the study period. During each clinic visit, patients were separated into one of four hypoglycemic categories based on the medical history since the preceding visit. These categories were: no reactions, mild to occasional reactions, mild to frequent reactions, and severe reactions. Reactions were considered severe if they were characterized by altered central nervous system function or prolonged sympathetic nervous system symptoms. Forty-seven percent of the patients reported at least one reaction during the 18-mo study period, but only 4% (i.e., 6 out of 147 patients) reported severe reactions. The mean hemoglobin A1c level was significantly lower in patients who reported reactions than in patients who did not report reactions [hemoglobin A1c values (x +/- SEM) = 7.78 +/- 0.1% vs. 9.48 +/- 0.1%, respectively; P less than 0.001]. The severity of hypoglycemia was inversely related to the degree of altered blood glucose control; episodes of frequent or severe symptomatic hypoglycemia occurred almost exclusively in patients with well-controlled diabetes as reflected in their near-normal hemoglobin A1c levels. There were no significant differences in mean insulin dose/kg, age, or duration of diabetes comparing patients in the four hypoglycemic categories. The results indicate that the hemoglobin A1c level can be a useful clinical guide to identify patients who are most likely to develop serious symptomatic hypoglycemia.

Role of endogenous prostaglandins in volume expansion and during furosemide infusion in conscious dogs

The renal effects of two structurally dissimilar inhibitors of prostaglandin synthesis (Meclofenamate and RO-20-5720) were studied in conscious, chronically instrumented dogs during mild volume expansion and during a constant infusion of furosemide. When either inhibitor was administered following volume expansion, urinary excretion of PGE2 and urine flow rate were reduced by more than 50%. In contrast, renal plasma flow fell by less than 10% while glomerular filtration rate, sodium excretion, and plasma renin activity (PRA) were unchanged. In separate studies, infusion of furosemide increased renal plasma flow, urine flow rate, sodium excretion, PRA, and urinary excretion of PGE2, while glomerular filtration rate decreased. Administration of inhibitors of prostaglandin synthesis during constant infusion of furosemide reduced the urinary excretion of PGE2 to control levels, as renal plasma flow and glomerular filtration rate fell below control level. Despite these hemodynamic alterations, the furosemide-induced diuresis and increase in PRA were only partly attenuated by prostaglandin inhibition. It is concluded that in conscious dogs, intrarenal prostaglandins modulate urine flow rate during mild volume expansion and play a major role in mediating the renal hemodynamic effects of furosemide.

Mutagenic activities of oxidized derivatives of N-nitrosodipropylamine in the liver cell-mediated and Salmonella typhimurium assays

The mutagenic activity of N-nitrosobis(2-oxopropyl)amine (BOP), N-nitroso(2-hydroxypropyl) (2-oxopropyl)amine (HPOP), N-nitrosobis(2-hydroxypropyl)amine (BHP), N-nitrosomethyl-2-oxopropylamine (MOP), and N-nitrosomethyl-2-hydroxypropylamine (MHP) was examined in the Ames liquid incubation assay, using hamster liver homogenate for metabolic activation, and in the hamster liver cell-mediated V79 cell assay. At similar concentrations, the cell-mediated assay showed a greater mutagenic response over background to these nitrosamines than did the bacterial assay. Also, the relative mutagenic potency in the cell-mediated assay (MOP > MHP > BOP > HPOP > BHP) correlated better than that in the Ames assay (HPOP > MHP greater than or equal to BOP = BHP = MOP) with overall carcinogenic potency in the hamster (MOP > BOP > HPOP > BHP). The liver cell-mediated assay may be an important adjunct to the battery of short-term tests for carcinogenicity prescreening.