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Biomedical subjects

C Cox

Publications and source records attributed to C Cox.

At least 469 records · Page 26Linked to original sources
PubMed1981

Cancer mortality at a Naval Nuclear Shipyard.

To evaluate a reported five-fold increase in leukaemia mortality among workers exposed to ionising radiation at Portsmouth (New Hampshire) Naval Shipyard (PNS), a retrospective cohort mortality study of all PNS civilian workers employed from 1952 to 1977 was done. Three subcohorts were identified: 7615 workers with radiation exposure of 0.001 to 91.414 rem (mean 2.779 rem, median 0.545 rem), 15 585 non-radiation workers, and 1345 workers selected for radiation work who received no measurable exposures. Vital status on 96% of the workers was ascertained and observed mortality due to all causes, all malignant neoplasms, and malignant neoplasms of the lymphatic and haematopoietic tissues, including leukaemia, was compared with that expected from mortality-rates for United States White males. Leukaemia mortality in radiation and non-radiation workers at PNS was also compared. Although the study had a power of greater than 99% to detect statistically a five-fold increase in leukaemia mortality among the radiation workers, and a power of 67% to detect a two-fold increase, there was no excess due to leukaemia or any other cause. The standardised mortality ratio for leukaemia among radiation workers was 84 (95% confidence interval, 34--174). There was no dose-response relation with radiation or any increased mortality in radiation over non-radiation workers. The study was, however, limited by short latency (time since first radiation); only 53% of the workers had less than 15 years' latency.

Humans↗
PubMed1981

Inhibition and recovery of growth processes in roots of Pisum sativum L. exposed to 60-Hz electric fields.

Roots of Pisum sativum L. were chronically exposed in aqueous inorganic nutrient medium to 60-Hz electric fields between 140 and 490 V/m (growth medium conductivity approximately 0.08 S/m). The growth rate, meristematic mitotic index, and growth rate recovery of the roots were determined. At 140 V/m there was no perturbation in growth rate or mitotic index. At 430 V/m the growth rate and the mitotic index were reduced. The mitotic index had a maximum depression (approximately 55% of control), which occurred at 4 h. The depression in growth rate was immediate and constant over time. When roots were exposed to an electric field at 430 V/m for 2 days, the growth rate was depressed by about 40%. When the field was terminated, the growth rate steadily increased and was almost normal after 5 days. At 490 V/m root growth rate was almost completely arrested. According to these results, there is a narrow range of induced membrane potentials that span the range from slightly altered to almost completely arrested growth rates.

Electromagnetic Fields↗
PubMed1981

Acute oral toxicity of butyl nitrite.

Butyl nitrite is present in consumer products subject to abuse by inhalation. When inhaled, intense peripheral vasodilation and tachycardia ensue, described by users as a 'rush'. When ingested, toxic sequelae include methemoglobinemia and hypokinetic anoxia. The median lethal oral dose to rats of this compound is, with 95% confidence, 83 +/- 3.5 mg kg-1.

Administration, Oral↗
PubMed1981

Metabolic and synthetic activities of Pneumocystis carinii in vitro.

Pneumocystic carinii organisms obtained from the lungs of rats with glucocorticoid-induced pneumocystosis retained a number of metabolic activities during in vitro culture for 48 to 72 h. They were able to metabolize [14C]glucose to 14CO2, to synthesize proteins from 3H-amino acids, and to synthesize ribonucleic acid from [3H]uridine. Utilization of [14C]glucose was inhibitable by excess unlabeled glucose, mannose, fructose, 2-deoxy-D-glucose, iodoacetate, and pentamidine, but not glycerol or trimethoprim-sulfamethoxazole. Protein synthesis was almost completely inhibited by incubation with high concentrations of cycloheximide, pentamidine, suramin, and chloroquine, but not by rifampin, tetracycline, or gentamicin. In additional experiments, P. carinii organisms that had been incubated overnight in the presence of potentially lethal agents were tested for their ability to utilize [14C]glucose in inhibitor-free medium as a test of viability. Pentamidine, at concentrations which caused only modest inhibition of glucose metabolism, protein synthesis, amino acid transport, or ribonucleic acid synthesis, was lethal, whereas trimethoprim-sulfamethoxazole was not.

Amino Acids↗
PubMed1981

Brainstem-evoked response audiometry: normative data from the preterm infant.

Brainstem-evoked response audiometry (BERA) was performed on 40 preterm infants who had low neonatal risk scores. Mean latencies for waves I and V were obtained from four age-groups, 33-34, 35-36, 37-38 and 39-40 weeks conceptional age. The results indicate that BERA is a valuable and reliable tool in assessment of auditory function in the preterm infant. Also for classification of abnormality it is recommended that 2 standard deviations from the mean latency of wave V be used.

Audiometry↗
PubMed1981

Extraction of light filth from tea: collaborative study.

The present AOAC method for determining insect and rodent filth in tea is time-consuming because it produced filter papers which are heavy in plant residue and therefore required long paper-reading times. A new method for the analysis of light filth in tea was developed to remedy existing problems and to improve recoveries. The method consists of the following steps: sample preparation, wet sieving, dilution with 40% isopropanol, flotation with mineral oil-heptane, and trapping off in a Wildman trap flask. In an interlaboratory collaborative study, analysts reported combined insect fragment recoveries of 99.2% for the proposed method and 93.0% for the AOAC method; the same analysts recorded combined rodent hair recoveries of 92.2% for the proposed method and 47.6% for the official method. Average times for reading individual subsamples were 9 min for the proposed method and 27 min for AOAC method. the proposed method has been adopted official first action.

Animals↗
PubMed1981

Tests of efficacy of antidotes for removal of methylmercury in human poisoning during the Iraq outbreak.

Three complexing agents and a thiolated resin were tested for their ability to reduce the T 1/2 of methylmercury in blood during an outbreak of human poisoning. The slope of the line relating the natural logarithm of the blood concentration to time during treatment was calculated by a parametric (linear regression) and a nonparametric (two-point) method. The mean slope for each treatment group was calculated and the T 1/2 was calculated from the mean slope. Both the linear regression and two-point methods yield similar mean values. The "two-point" T 1/2 will be quoted here. The mean T 1/2 in six patients receiving no specific treatment was 65 days and in 10 patients receiving placebo was 61 days, and these values did not differ from those reported in the literature. All four treatments significantly reduced the mean T 1/2 values below the mean for the combined placebo and no treatment groups. Sodium 2,3-dimercaptopropane-1-sulfonate was the most effective agent, reducing the mean T 1/2 in 10 patients to 10 days. The thiolated resin given to eight patients produced a mean T 1/2 of 20 days. The penicillamines also produced a significant reduction in T 1/2 values; the mean T 1/2 for D-penicillamine in 12 patients was 26 days and N-acetyl-DL-penicillamine in 17 patients yielded a mean T 1/2 of 24 days. This is the first report of the effects of sodium 2,3-dimercaptopropane-1-sulfonate and resin in human subjects exposed to methylmercury. No adverse effects were observed in any of the treatment groups. A clinical trial was not possible but it is concluded that agents that reduce blood levels and accelerate excretion are probably clinically useful if given before irreversible damage has occurred.

Adolescent↗
PubMed1980

Comparison of sex steroid receptor analyses and carcinoembryonic antigen with clinical response to hormone therapy.

This study corroborates previous reports which suggested the efficacy of estrogen receptor (ER) analysis in predicting responses of patients with metastatic mammary carcinoma to hormonal therapeutic manipulation. The predictive value of multiconcentration titration and sucrose density gradient analyses of ERs and progesterone receptors (PRs) are compared. The predictive value of ER analyses can be improved by the discrimination of 8S versus 4S binding species or by the use of PR analysis in combination with ER analysis. The tumor-associated antigen, carcinoembryonic antigen (CEA), is evolving as an important quantitative aid in evaluating the clinical responses to patients receiving hormonal therapy.

Adrenalectomy↗
PubMed1980

Behavioral responses to artificial food colors.

Twenty-two young children, maintained on a diet that excluded certain foods, were challenged intermittently with a blend of seven artificial colors in a double-blind trial. Parents' observations provided the criteria of response. One child that responded mildly to the challenge and one that responded dramatically were detected. The latter, a 34-month-old female, showed a significant increase in aversive behaviors. These results further confirm previous controlled studies.

Behavior↗
PubMed1980

Deficits in short-term auditory memory for verbal material following right temporal removals in humans.

Right, as well as left, temporal patients were significantly impaired on shot-sterm auditory memory for consonant trigrams. The severity of the deficit shown by both groups was not related to the association value (low, medium, high) of the trigrams or the duration of the intertrial intervals (from 6 sec to 1 min) used in this study. Right temporal patients were also deficient on tests of tonal memory and delayed facial recognition. The results are discussed in terms of a sequential model of information processing involving modality-specific short-term memory and material-specific long-term retention.

Adult↗
PubMed1979

An evaluation of Corynebacterium parvum during remission maintenance therapy in pediatric patients with acute lymphoblastic leukemia.

The biologic impact and clinical toxicity of Corynebacterium parvum administered at a dose of 5 mg/M2 by intravenous or subcutaneous routes were evaluated in 18 children receiving combination chemotherapy for maintenance of acute lymphoblastic leukemia (ALL) in remission. Several nonspecific immunologic and hematologic parameters were evaluated. Patients were also monitored for changes in cutaneous sensitivity to histamine. No changes in any parameter were observed in patients after only one course of C parvum injection. However, after 6-10 courses, glass-adherent peripheral blood leukocytes of C parvum-treated patients augmented the response of PHA-stimulated autologous lymphocytes. In all nine patients studied who received C parvum injection subcutaneously for at least six months, there were significant increases in the mean bone marrow myelocyte-erythrocyte (ME) volumes compared to pretreatment values. These results suggest that periodic evaluations are desirable in patients receiving repeated administration of C parvum, since changes in immunologic and hematologic responses may be demonstrable only after several injections. In contrast to the reported experience in adults, subcutaneous C parvum administration children was not well tolerated, whereas intravenous infusion was generally well tolerated.

Acute Disease↗
PubMed1979

Behavioral epidemiology of food additives.

Behavioral toxicology in the natural environment can be considered a special branch of epidemiology. Behavioral epidemiology, because it typically relies on complex functional criteria, faces all of the problems of behavior measurement posed by uncontrollable variation, and amplified even further by chemical exposure. Many such issues arose in a study of behavioral responses to artificial food colors in children. Difficulties in employing Applied Behavioral Analysis in such a context run the gamut from selection of retrospective criteria to appropriate statistical models.

Child↗