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Biomedical subjects

J A Hall

Publications and source records attributed to J A Hall.

At least 181 records · Page 10Linked to original sources
PubMed1984

The impact of health and safety committees. A study based on survey, interview, and Occupational Safety and Health Administration data.

In a study conducted to determine if the existence of a joint labor-management health and safety committee (HSC) was correlated with either the number of Occupational Safety and Health Administration (OSHA) complaints or hazardousness, as measured by OSHA serious citations, virtually no effect could be detected in a sample of 127 Massachusetts manufacturing firms. At a sample of 13 firms, interviews of HSC members were conducted. Committee attributes and perceptions about committee effectiveness were compared with the number of OSHA complaints and serious citations. There were fewer complaints and fewer serious citations at firms with HSCs that were perceived as effective. Results of the study suggest that the objective attributes of the committee may be less important to its success than the commitment of management and labor to solving workplace safety problems.

Data Collection↗
PubMed1983

The incorporation of O6-methyldeoxyguanosine and O4-methyldeoxythymidine monophosphates into DNA by DNA polymerases I and alpha.

The modified nucleoside 5'-triphosphates O6-MedGTP ad O4-MedTTP have been synthesised and their acceptability as DNA-precursors investigated using DNA polymerases I and alpha in an in vitro assay. O6-MedGMP is only incorporated into newly-synthesized DNA-like material in the presence of templates containing thymine bases. Similarly O4-MedTMP is only incorporated in the presence of templates containing guanine bases. The results confirm the promutagenic nature and base-pairing properties of O6-MeG ad O4-MeT.

DNA Polymerase I↗
PubMed1983

The action of thrombin on peptide p-nitroanilide substrates. Substrate selectivity and examination of hydrolysis under different reaction conditions.

Kinetic parameters for the action of bovine alpha-thrombin on 24 commercially available peptide p-nitroanilides have been determined. The selectivity constant, kcat/Km, ranges from 3.3 X 10(1) to 1.1 X 10(8) M-1 X S-1 for the poorest and the best substrates, respectively. The best substrates for thrombin were identified as those with arginine in the P1 position, proline or a proline homolog in the P2 position, and an apolar amino acid in the P3 position. Quantitative distinction between lysine and arginine in the P1 position and other amino acids in the P2-P4 positions of the substrate is reported from the changes in the kinetic parameters for substrates differing in only a single amino acid in these positions. Effects of NaCl, CaCl2 and poly(ethylene glycol) concentrations, pH and temperature on the action of thrombin on selected substrates have been assessed. A source of large systematic error in thrombin concentration estimates was identified as resulting from adsorption losses. These losses were eliminated by inclusion of poly(ethylene glycol) in dilution and reaction buffers.

Aniline Compounds↗
PubMed1982

The action of thrombin on peptide p-nitroanilide substrates: hydrolysis of Tos-Gly-Pro-Arg-pNA and D-Phe-Pip-Arg-pNA by human alpha and gamma and bovine alpha and beta-thrombins.

Human and bovine alpha-thrombins (greater than 90% alpha form) with high fibrinogen clotting activities (approximately 3,000 U.S. units/mg protein) exhibit similar Michaelis menten kinetics with the p-nitroanilide tripeptide substrates Tos-Gly-Pro-arg-pNA (Chromozym-TH) and D-Phe-Pip-Arg-pNA (S-2238). The kinetic parameters at I = 0.11 M, 25 degrees C, pH 7.8 are: (Km = 4.18 +/- 0.22 and 3.61 +/- 0.15 microM; kcat = 127 +/- 8 and 100 +/- 1 s-1) for Chromozym TH and (Km = 1.33 +/- 0.07 and 1.50 +/- 0.10 microM; kcat = 91.4 +/- 1.8 and 98.0 +/- 0.5 s-1) for S-2238 for the human and bovine enzymes, respectively. Unlike the native enzyme forms, their "non-clotting" terminal degradative forms, human gamma-thrombin (approximately 5 units/mg) and bovine beta-thrombin (approximately 200 units/mg), give increased values for these parameters (km = 14.3 +/- 2.4 and 14.4 +/- 2.2 microM; kcat = 160 +/- 9 and 124 +/- 6 s-1) for Chromozym-TH; and (Km = 2.50 +/- 0.36 and 2.99 +/- 0.33 microM; kcat = 106 +/- 3 and 106 +/- 3 s-1) for S-2238. Based on these parameters, 50% degradation of human or bovine alpha-thrombins can be calculated to produce relatively small errors in the kinetic measurement of total thrombin concentrations (maximally 9% and 7% for Chromozym-TH; 7% and 3% for S-2238, respectively) if the kinetic parameters for all alpha forms are erroneously used and assays are at 150 microM substrate. This is in contrast to the large errors inherent in clotting activity measurements on thrombin mixtures. Incorporation of 1 mg/ml of polyethylene glycol 6,000 into assay solutions eliminates systematic errors otherwise caused by thrombin adsorption to surfaces and enables thrombin to be accurately assayed at concentrations less than 0.1 nM or 0.01 clotting unit/ml of alpha-thrombin.

Adsorption↗
PubMed1982

pH dependence of short-circuit current and active phosphate transport by toad bladder.

The effect of changing the pH of the mucosal and serosal bathing solutions on active Na transport (estimated by the short-circuit current) and active inorganic phosphate (Pi) transport was studied in the toad bladder. The short-circuit current was unaffected by lowering the pH from 7.6 to 7.1 but was inhibited (29-45%) at pH 6.6, 8.1, 8.6, 9.1, or 9.6. The Pi transport was not changed when the pH was increased from 7.6 to 8.1, but was totally inhibited at pH 6.6, 7.1, 8.6, 9.1 or 9.6. Thus, active transport of Pi occurs only when most of the Pi is HPO4(-2), but the effect of varying pH on active Pi transport in the toad bladder is more complicated than a simple titration of Pi.

Animals↗
PubMed1981

The induction of errors during in vitro DNA synthesis following chloroacetaldehyde-treatment of poly(dA-dT) and poly(dC-dG) templates.

Chloroacetaldehyde, a rearranged metabolic product of the human carcinogen vinyl chloride, reacts with the DNA-like polymers poly(dA-dT) and poly(dC-dG) to form etheno-adducts of the adenine and cytosine bases. These treated polymers, when used as templates for E. coli DNA polymerase I in an in vitro assay, show a decreased ability to direct DNA synthesis. At the same time, increased relative levels of non-complementary nucleotides are incorporated. With the poly(dA-dT) templates 1 dGMP residue is incorporated for every approx 60 ethenoadenine residues present whilst no increased misincorporation of dCMP was detected. With the poly(dC-dG) templates 1 misincorporation of dAMP or dTMP occurred in the presence of approx 30 and 80 ethenocytosine residues respectively. A nearest neighbour analysis shows that with the modified poly(dC-dG) templates the majority of the errors were incorporated opposite cytosine (or modified cytosine) bases.

Acetaldehyde↗
PubMed1981

Religious symbols in dreams of analytical patients.

My purpose has been to call attention to the special meanings of religious images in dreams. It is neither possible nor desirable to make rigid rules as to their interpretation; some basic guidelines, however, may be helpful. For religious images that are active and meaningful in the conscious mind of the dreamer, interpretation may be unnecessary, since they may appear in such a way as to modify other contents of the psyche. If the consciously active religious image appears in a surprising way, this may indicate that the boundaries of value in the personal levels of the mind are under pressure for revision from deeper structures. Religious images that come from outside the conscious tradition of the dreamer may require little more than personal amplification if they are known in the conscious associations of the dreamer. If they are outside the personal associations, however, they may be difficult to amplify, although they frequently seem to be appropriately used by the dream-making function of the mind, the Self. Such unconscious but appropriate uses of verifiable archetypal images raise profound questions about the nature of the psyche, but do not greatly modify analytical practice, since images are frequently meaningful in their context alone. Contextual religious images indicate a high value in symbols that may have been consciously overlooked, like the "orphaned" philosopher's stone. Contextual religious images often indicate the need to consider revision of the conscious hierarchy of values.

Dreams↗
PubMed1980

Affect and verbal-nonverbal discrepancy in schizophrenic and non-schizophrenic family communication.

Verbal and nonverbal communication of affect was examined in schizophrenic and control families, using audio tapes and transcripts of family interactions. In Study 1, data were available for parents interacting with their schizophrenic child (index session) or with a well child (well-sibling session), and for two parent-child sessions in normal families. In Study 2, data consisted of index sessions only with schizophrenic, non-schizophrenic psychiatric, and normal families. Audio tapes were electronically filtered, and ratings were obtained on nonverbal (filtered speech) and verbal (transcript) samples. The double-bind hypotheses of different nonverbal expression of affect and greater verbal-nonverbal discrepancy in schizophrenic as compared to normal families were not supported. In both studies no overall differences were found between diagnostic groups in terms of nonverbal ratings, indicating that clinical perceptions of inappropriate and conflicted affect in schizophrenic families are not based on spontaneously produced simultaneous discrepancy between verbal and nonverbal channels of spoken communication.

Affect↗
PubMed1979

Positive rubella titers in pregnancy: a question of validity.

A review of 25 patients with more than 1 rubella titer by hemagglutination-inhibition testing revealed 3 patients with high positive titers that were reported to be negative in subsequent pregnancies. None of the patients had received the rubella vaccine. Because the sensitivity and reliability of hemagglutination-inhibition testing is markedly influenced by multiple variables, it is important for both the clinician and the pathologist to be aware of both the limitations of the testing method and the meaning of an antibody titer on a single isolated specimen.

Antibodies, Viral↗
PubMed1978

Effect of sodium transport inhibition on active phosphate transport by toad bladder.

The relationship between active Na transport (estimated by the short-circuit (SCC)) and active inorganic phosphate (Pi) transport was studied in the toad bladder. When SCC was inhibited by amiloride, ouabain, or removal of K from the serosal bathing solution, active Pi transport was totally inhibited. When Na was replaced isotonically by choline in either the mucosal bathing solution or both the mucosal and serosal bathing solutions, there was no measurable SCC or active Pi transport. These experiments are compatible with the hypothesis that active Pi transport occurs only in the presence of active Na transport.

Amiloride↗
PubMed1978

The role of cyclic AMP in parathyroid hormone action in the toad bladder.

Parathyroid hormone (PTH) inhibited active transport of inorganic phosphate and stimulated an increase in cyclic AMP concentration in the urinary bladder of the toad, Bufo marinus. Active transport of phosphate in the toad bladder was also inhibited by an analog of cyclic AMP (dibutyryl cyclic AMP) and by other drugs (pitressin and theophylline) which increase toad bladder intracellular cyclic AMP concentration. These data support the concept that cyclic AMP may be the mediator of PTH-induced phosphate transport inhibition in the toad bladder.

Animals↗
PubMed1978

Hypnosis.

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Humans↗