Effects of chlordiazepoxide and d-amphetamine on responding suppressed by conditioned punishment.

Key pecking by two pigeons, maintained under a variable-interval two-minute schedule of food presentation, was suppressed when each response produced a five-second visual stimulus that was occasionally paired with shock. Stimulus-shock pairings occurred independently of responding according to a variable-time six-minute schedule for one bird or once per session for the other bird. The effects of chlordiazepoxide and d-amphetamine were assessed on this baseline of behavior suppressed by conditioned punishment.

Relationships of maternal weight gain, prepregnancy weight, and infant birthweight. Interaction of weight factors in pregnancy.

A study of the effects of restricted vs. unrestricted maternal caloric intakes upon infant birthweights was conducted in a large, middle-class, private obstetrical practice in Madison. Wis.

Nuclear magnetic resonance study of the exchangeable histidine protons in bovine and wheat germ superoxide dismutases.

Nuclear magnetic resonance studies at 220 MHz of the exchangeable histidine NH protons in bovine erythrocyte superoxide dismutase (BESOD) [EC 1.15.1.

Subclinical effects of chronic increased lead absorption--a prospective study. III. Neurologic findings at follow-up examination.

Neurologic examination, nerve conduction testing and electro-oculographic testing have been performed at a baseline examination and a follow-up examination in a group of lead workers with blood lead levels predominantly between 60 and 80 micrograms/dl and in a group of control workers. A statistically significant decreased saccade accuracy measurement in the lead workers compared to the controls was found at both examinations. No other simple test or pattern of findings differentiated between the lead workers and the controls, and the biological significance of the lower saccade accuracy is not clear.

Cigarette smoking and lead levels in occupationally exposed lead workers.

One hundred eleven workers at a secondary Pb smelter were surveyed to determine smoking and personal hygiene habits. Fifty-three percent of the smokers had blood Pb levels in excess of 60 micrograms/dl, compared to 31% of nonsmokers (p = 0.02).

Selenium concentrations and glutathione peroxidase activities in a population exposed to selenium via drinking water.

Selenium concentrations in blood, urine, hair, and tap water were determined in samples obtained from individuals exposed to varying amounts of the element in water form home wells. Glutathione peroxidase activities were also determined on the blood samples. Correlations of blood Se with the enzyme activity were not statistically significant.

The usefulness of a predictive instrument to reduce inappropriate admissions to the coronary care unit.

A mathematical instrument was developed to supplement the diagnostic information available to physicians in the emergency room to improve physicians' diagnostic accuracy in managing patients with acute ischemic heart disease and thereby reduce inappropriate coronary care unit admissions. The instrument was empirically derived and is based on nine clinical, historical, and electrocardiographic predictive variables. Probabilities of acute ischemic heart disease generated by the instrument were given to the house staff in an emergency room during alternate months.

pH-dependent migration of copper(II) to the vacant zinc-binding site of zinc-free bovine erythrocyte superoxide dismutase.

Bovine erythrocyte superoxide dismutase (Cu(2)Zn(2)SODase; superoxide:superoxide oxidoreductase, EC 1.15.1.

Subclinical effects of chronic increased lead absorption--a prospective study. II. Results of baseline neurologic testing.

This report summarizes the results of baseline neurologic testing in a group of apparently healthy workers from a secondary lead smelter and a group of controls from nearby aluminum processing plants. The test battery included a standard neurologic examination nerve conduction measurements, quantitative oculomotor function tests and detailed audiologic studies. Lead workers and controls were intermixed so that the examiners were unaware of the status of any individual being tested.

Subclinical effects of chronic increased lead absorption--a prospective study. I. Study design and analysis of symptoms.

Seventy workers exposed to lead for at least one year and 35 control workers have been enrolled in a prospective study of possible neurologic effects of chronic lead absorption at or below the current standard of 80 microgram per 100 ml whole blood. The study design is described in detail. Initial results of analysis of lead-related symptoms from baseline studies indicate few differences between the exposed and nonexposed workers.

Coupling between oxidation state and hydrogen bond conformation in heme proteins.

In all heme proteins for which crystal structures are available, the N(epsilon) of a histidyl residue is bonded to the heme iron and N(delta) is hydrogen bonded to a carbonyl oxygen of the peptide backbone. We investigate here the possibility that a change in oxidation state of the iron or a change in the geometry of this hydrogen bond might change the hydrogen bond strength in a functionally significant way. Dimerization energies obtained from ab initio molecular orbital calculations on the hydrogen-bonded dimer of imidazole and planar formamide are used to represent the strength of this hydrogen bond in heme proteins.

Selenium levels in human blood, urine, and hair in response to exposure via drinking water.

Blood, hair, urine, and tap water samples were obtained from participants in a population exposed to varying amounts of selenium via water from home wells. Concentrations of selenium in urine and hair produced significant positive correlations with well-water selenium levels. Blood selenium with well-water selenium did not produce a significant correlation.

Double-blind trial of thiothixene and chlorpromazine in acute schizophrenia.

In a double-blind trial of chlorpromazine and thiothixene conducted with 79 acutely ill, newly hospitalized schizophrenic patients, chlorpromazine and thiothixene were shown to be equally effective in producing meaningful symptomatic improvment over an average period of approximately 3 weeks, as measured by Global Assessments (CGI), BPRS, and NOSIE.

Zinc, iron, copper, and magnesium concentrations in tissues of rats fed various amounts of zinc.

An experiment was conducted with rats to determine the effects on the tissue concentrations of Zn, Fe, Cu, and Mg of feeding various amounts of zinc. The rats were pair-fed one of the following diets for four weeks: Diet A, a zinc-deficient diet; a diet containing the recommended amoun of zinc (diet A plus 55 microgram of zinc per gram of diet), or diet A plus 550 microgram zinc per gram of diet. Concentrations of these elements in various tissues were determined by atomic absorption spectrometry after wet digestion.

High-pressure liquid chromatographic--mass spectrometric determination of delta9-tetrahydrocannabinol in human plasma following marijuana smoking.

A method was developed for analyzing delta9-tetrahydrocannabinol (I), a psychotomimetic constituent found in marijuana smoke. The developed method utilizes a high-pressure liquid chromatographic (HPLC) gradient elution program to separate I from the other major cannabinoids in marijuana smoke. To achieve the sensitivity required to detect I in human plasma following marijuana smoking, a mass spectrometric quantification method was developed to analyze the HPLC eluant.

Nuclear magnetic resonance and chemical modification studies of bovine erythrocyte superoxide dismutase: evidence for zinc-promoted organization of the active site structure.

Nuclear magnetic resonance (NMR) spectroscopy of the exchangeable protons, tentatively assigned as histidine resonances, of bovine erythrocyte superoxide dismutase in H2O has been found to be a powerful method to study the active site of the enzyme. This technique has been employed in conjunction with chemical modification of the histidine residues using diethylpyrocarbonate (DEP) to show that zinc alone organizes the active site structure. All eight histidines per subunit of apoenzyme react with DEP.

Comparative plasma concentrations of quinidine following administration of one intramuscular and three oral formulations to 13 human subjects.

A GLC method, based on flame-ionization detection, was developed for the assay of methotrimeprazine and its sulfoxide in plasma. For a 6-ml aliquot, the sensitivity was 2-3 ng/ml for the unchanged drug and 4-5 ng/ml for the sulfoxide. The coefficient of variation, calculated from duplicate analyses of plasma samples, was 8-15% for concentrations between 10 and 100 ng/ml.