Search PubMed⌕ Search

Biomedical subjects

J Harris

Publications and source records attributed to J Harris.

At least 397 records · Page 22Linked to original sources
PubMed1984

A proportionate mortality analysis of California agricultural workers, 1978-1979.

There are few published reports of epidemiologic studies of the risks of agricultural work. Members of this occupational group have been of special concern because of their exposure to pesticides, some of which are mutagens and animal carcinogens. A previous proportionate mortality study of California agricultural workers was based on deaths recorded among white males of this occupational group during 1959-1961. We have conducted a proportionate mortality analysis of all deaths recorded during 1978-1979 among California farm workers and farm owner/managers. In general, the findings of our study are consistent with those of the previous study. For farm workers, we found proportionate mortality ratios (PMRs) which were consistently elevated for all race and sex categories (in which there were 6 or more decedents) for deaths due to motor vehicle accidents, all respiratory disease, and all infective and parasitic diseases. The PMRs for the former three causes of death were also found to be elevated across several race and sex categories for farm owner/managers. We also found a significant and consistent deficit of deaths among farm workers and farm owner/managers due to arteriosclerotic heart disease. The proportionate cancer mortality ratios (PCMRs) for cancer of the stomach and cancer of other lymphatic tissue were elevated, although not necessarily statistically significantly, for several race and sex categories among farm workers and farm owner/managers. The PCMR for cancer of the cervix was statistically significant for white female farmworkers.

Accidents↗
PubMed1984

Venom of the Australian rough-scaled snake, Tropidechis carinatus: lethal potency and electrophysiological actions.

A series of experiments to define the lethal potency (LD50) and electrophysiological properties of the venom of the Australian Rough-scaled Snake (Tropidechis carinatus) are described. Crude pooled venom contains at least five fractions which were separated using liquid chromatography and high pressure liquid chromatography techniques (Fractions I-V). LD50 studies are reported using each of these fractions, with data for both adult and neonatal mice. Fraction I (mol. wt greater than 100,000) was essentially non-toxic. Fraction IV (mol. wt less than or equal to 10,000) and Fraction V (mol. wt less than 1,000) were potent toxic components with LD50'S (s.c. injection; fraction in 0.1% bovine serum albumin and 0.85% saline; neonatal mice) of 0.04 mg/kg and 0.06 mg/kg respectively. LD50'S for the whole crude venom were similar in both adult and neonatal mice. Electrophysiological studies using a Bulbring preparation (rat isolated phrenic nerve-hemidiaphragm) indicated that Fractions I, IIa and IIb were inactive. Fraction IV (mol. wt less than or equal to 10,000) caused rapid neuromuscular blockade which appeared to be irreversible. Neurophysiological experiments with a rat isolated extensor digitorum longus muscle preparation suggested that the major toxic activity of the whole venom resides in Fractions III and IV, and that both of these fractions have presynaptic and postsynaptic action.

Animals↗
PubMed1984

A mini-residency program in orthognathic surgery.

A method of teaching major orthognathic surgical techniques is presented. One hundred hours of instruction in laboratory, practical, clinical, and operating room experiences were presented over two months, on alternate weekends. These intervals allowed for assimilation of new didactic material, readings, and study and laboratory exercises at home. Four teams of three oral and maxillofacial surgeons rotated to the operating rooms during each weekend session to experience hands-on training. The protracted period of follow-up observations enabled participants to witness most cases from start to finish and learn to anticipate and manage sequellae. Experienced oral and maxillofacial surgeons demonstrated a quick grasp of newer techniques of orthognathic surgery, and most translated the mini-residency experience into their practices.

Cephalometry↗
PubMed1984

Arresting but misleading phrases.

This paper discusses some common misconceptions of what a utilitarian approach to medical ethics is and of the conclusions it forces upon those disposed to accept such an approach. It suggests that broad and unargued characterisations of approaches to moral questions as 'utilitarian', 'Hippocratic' or whatever are likely to be misleading and counterproductive. What matters is not what to call the position that people feel inclined to accept but rather what arguments there are in its favour and what arguments there are against it.

Aged↗
PubMed1984

The detection of circulating immune complexes containing C1q and IgG using a new rapid serum ELISA test system.

An ELISA sandwich assay for detecting circulating immune complexes (CIC) was evaluated. Heat-aggregated IgG (HAG) containing Clq (HAG:Clq) is used to generate standard curves for quantitation of CIC. Sera from 488 normal donors had an means of 3.8 +/- 15.3 micrograms/ml HAG eq and 97.1% had concentrations less than 35 micrograms/ml HAG eq (2 SD greater than means) and were considered negative. Sera from rheumatoid arthritis (RA) patients in active disease tested 86% positive for CIC (means = 104.5 +/- 63.4 micrograms/ml HAG eq) while 100% with inactive disease were negative (means = 11.4 +/- 3.7 micrograms/ml HAG eq). Similarly, in systemic lupus erythematosus (SLE) patients with active disease, 100% were positive (means = 133.1 +/- 50.6 micrograms/ml HAG eq) while 80% with inactive disease were negative (means = 20.4 +/- 21.4 micrograms/ml HAG eq). In AIDS (AIDS related), 88.5% of AIDS sera and 77.1% of lymphadenopathy syndrome (LAS) sera had elevated CIC. Sera from asymptomatic homosexual controls showed 85% positive for CIC. The serum ELISA test for CIC compared favorably with the 125I-staphylococcus binding assay but was more sensitive than the 125I-C1qBA. The OKT4/OKT8 ratios were also significantly reduced in AIDS and LAS.

Acquired Immunodeficiency Syndrome↗
PubMed1983

An electron-spin-resonance spin-label study of the interaction of purified Mojave toxin with synaptosomal membranes from rat brain.

The structural properties of isolated purified rat brain synaptosomal membranes, both in the presence and absence of purified active toxin of the Mojave snake Crotalus scutulatus scutulatus, were studied by spin-label electron spin resonance techniques. The spectra from eight different positional isomers of nitroxide-labelled stearic acids, a rigid steroid androstanol, and a spin-labelled phosphatidylcholine intercalated into the synaptosomal membranes, were obtained as a function of temperature from 4-40 degrees C. The flexibility gradient (from spin-label order parameters) and polarity profile (from isotropic splitting factors) across the synaptosomal membranes, was characteristic for lipid bilayers. The nitroxide spin-labelled steroid, androstanol, intercalated into the synaptosomal membrane, revealed the abrupt onset of rapid cooperative rotation about the long axis of the molecule at 12 degrees C showing that the lipid molecules are rotating rapidly around their long axes at physiological temperatures. The presence of the Mojave toxin affected the synaptosomal membrane in a complex manner, depending upon the temperature and the position of the nitroxide label on the alkyl chain of the stearic acid probe. Mojave toxin exerted little effect on the flexibility gradient of the synaptosomal membrane at 20 degrees C, a temperature at which the acyl chain labels detected a structural change in the membranes. At temperatures lower than 20 degrees C, the Mojave toxin produced a change in the flexibility gradient of the synaptosomal membrane which indicated an increased disordering in the upper region of the membrane and a concomitant increased ordering of the acyl chains in the deeper regions of the membrane. At temperatures higher than 20 degrees C, the order profile of the synaptosomal membrane was shifted by the presence of the Mojave toxin in a manner which indicated that the outer parts of the membrane were more rigid and the inner regions more fluid, than in controls. A cross-over point for the perturbation occurred at C8-9, which is about 12-14 A into the membrane. This is the approximate depth of the hydrophobic pocket shown in pancreatic phospholipase A2 [Drenth et al. (1976) Nature (Lond.) 264, 373-377], a protein likely to be homologous to the basic subunit of the toxin. At all temperatures, rotational lipid motion was inhibited by the toxin as indicated by the steroid probe. The electron spin-resonance spin-label results are interpreted in terms of the partial penetration of the basic subunit of the intact toxin into the membrane, disordering the ordered chains at low temperature and ordering the disordered chains at physiological temperatures. The purified individual toxin subunits did not perturb the membrane lipids at physiological temperatures implying that both subunits must be associated for activity of the toxin which is confirmed by toxicity studies.

Animals↗
PubMed1983

Self-mutilation.

Explore the source record for details and available documents.

Abdomen↗
PubMed1983

Must doctors save their patients?

Do doctors and other medical staff have an obligation to treat those who need their help? This paper assumes no legal or contractual obligations but attempts to discover whether there is any general moral obligation to treat those in need. In particular the questions of whether or not the obligation that falls on medical staff is different from that of others and of whether doctors are more blameworthy than others if they fail to treat patients are examined. Finally we look at the question of the burden of this obligation and at the responsibility of society to mitigate its hardships.

Contracts↗
PubMed1983

Clinical studies of measuring extravascular lung water by the thermal dye technique in critically ill patients.

We measured extravascular lung water (EVLW) by the thermal-dye technique in a broad group of critically ill patients who had either acute cardiac or noncardiac illnesses. A portable AP supine chest roentgenogram, reviewed blindly, was used to classify patients as to the presence or absence of pulmonary edema; by clinical history we categorized patients into either a cardiac or noncardiac (ie, ARDS) group. With a normal chest roentgenogram, the mean EVLW was 5.6 +/- 1.8 ml/kg, and the pulmonary capillary wedge pressure (PCWP) was 11.3 +/- 5.3 mm Hg (mean +/- SD). In contrast, patients with pulmonary edema on a cardiac basis had a mean EVLW of 10.2 +/- 3.1 ml/kg (mean PCWP, 20.5 +/- 8.2 mm Hg), while patients with clinically defined noncardiac pulmonary edema and a normal PCWP (11.6 +/- 5.7 mm Hg) had a mean EVLW of 15.8 +/- 4.6 ml/kg, significantly higher than in the cardiac group (p less than 0.001). On a severity system of 014, the EVLW increased in parallel to the severity of the chest radiologic appearance of edema in both the cardiac (r2 = .44; p less than 0.001) and noncardiac (r2 = .59; p less than 0.001) patients. This study defined a normal range of thermal-dye EVLW in critically ill patients without radiologic evidence of pulmonary edema. We further demonstrated the increased pulmonary microvascular permeability of noncardiac pulmonary edema compared with cardiac edema by the greater EVLW at normal microvascular hydrostatic pressures in the former group.

Adult↗