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Biomedical subjects

C Cox

Publications and source records attributed to C Cox.

At least 451 records · Page 25Linked to original sources
PubMed1983

Worker exposure to perchloroethylene in the commercial dry cleaning industry.

The National Institute for Occupational Safety and Health (NIOSH) conducted industrial hygiene surveys at 44 commercial dry cleaning facilities in five states as part of an industry wide study to assess the health effects of long-term, low-level exposure to perchloroethylene (PCE). Time-weighted average (TWA) and peak exposures to PCE were determined by collecting personal air samples using activated charcoal tubes and battery-operated pumps. TWA exposures of the machine operators ranged from 4.0 to 149.0 ppm PCE. The geometric mean PCE exposure of the machine operators (22 ppm) differed significantly from the mean exposures of the pressers (3.3 ppm), seamstresses (3.0 ppm), and the concentrations in the front counter areas of the facilities (3.1 ppm). Te geometric mean 5-minute peak PCE exposure during textile transfer was 44 ppm while the mean 15-minute exposure was 33 ppm. No significant differences were found between exposures when either the TWA or the peak data were grouped by geographic location (i.e., state), or by the type of processing equipment used (i.e., "Combination" units vs. separate washing and drying units). Recommendations for work practices, ventilation, maintenance, plant layout and personal protective equipment are presented to reduce PCE exposures to lowest achievable levels.

Humans↗
PubMed1983

Public health consequences of heavy metals in dump sites.

Metals differ from most synthetic organic chemicals in that their clinical manifestations are well known and methods for their measurement in the body are generally well established. Since metals are ubiquitous, special care should be taken to identify the source, whether dump site or not. Isotopic ratios may be used for lead. Time of exposure may be highly variable so estimates will be necessary of integrated "dose-commitment." Transmission to man will follow many pathways. The contamination of children's hands and clothing by dust may be an important route. Because effects are so different, the chemical species (e.g., organic versus inorganic forms) of each metal must be identified. Exposure assessment requires identification of suitable indicator media, usually blood in the case of lead, urine with cadmium and inorganic mercury, and blood or hair with regard to methylmercury. Human head hair may have considerable potential, as it may provide a recapitulation of past exposures. The first health complaints associated with most metals are usually nonspecific. The complex social, political, and legal issues strongly indicate the need for objective tests for health effects. Most important is the identification and measurement of the critical effect, i.e., an effect that alerts the public health authorities that further exposure should cease. For example, in the case of lead, the critical effect is hematologic; with cadmium it is the presence in urine of abnormally high concentration of small molecular weight protein; and with mercury no early objective test has yet been devised.

Adult↗
PubMed1982

Analgesic efficacy of parenteral metkephamid acetate in treatment of postoperative pain.

The analgesic efficacy and side-effects of a single parenteral dose of metkephamid acetate 70 mg were compared with those of pethidine (meperidine) hydrochloride 100 mg and placebo in a double-blind, randomised, controlled clinical trial. 30 out of 32 postoperative patients completed the study--10 in the metkephamid group, 11 in the pethidine group, and 9 in the placebo group. The time-effect curves of summated pain measures and analyses of derived measures all indicated that the analgesic activity of metkephamid 70 mg was significantly greater than that of placebo and not less than that of pethidine 100 mg. The metkephamid group had a greater incidence of side-effects than the other two treatment groups. Some side-effects, such as sensations of heaviness of the extremities and nasal congestion, were peculiar to metkephamid but not distressing.

Adolescent↗
PubMed1982

Phospholipase A2 activity in the rat uterus during early pregnancy.

The activity of phospholipase A2 (PLA2), which provides free arachidonic acid and is widely accepted as the rate-limiting step in the biosynthesis of prostaglandins (PGs), was determined by radioisotopic method in the rat uterus on days 1 through 6 of pregnancy. Serum levels of progesterone (P4) and estradiol-17 beta (E2) were also determined by radioimmunoassay. Uterine PLA2 activity peaked in the morning of day 4 of pregnancy (15.85 +/- 2.44 nmol/h/mg protein). While the activity was low (5.78 +/- 0.80) in the morning of day 5 of pregnancy, a small peak (9.12 +/- 1.62) was noticed in the afternoon of day 5. Serum P4 levels, as expected, showed a gradual increase with the advancement of pregnancy, but the serum E2 levels in the same samples were undetectable under our assay conditions. The results are discussed in relation to the hormonal control of PLA2 activity and hence PG production in the uterus during early pregnancy.

Animals↗
PubMed1982

Occupational exposures to radiofrequency radiation (18-31 MHz) from F dielectric heat sealers.

The National Institute for Occupational Safety and Health (NIOSH) has initiated an epidemiologic study to evaluate whether or not radiofrequency (RF) radiation in the 10--100 MHz range has any effects on the reproductive functions of exposed workers. Initial investigations indicated that a suitable population for this study might exist in industries utilizing RF dielectric heat sealers. To estimate exposure levels of RF heat sealer operators, NIOSH made exposure measurements for 82 operators in 13 facilities with a Narda Broadband Isotropic Radiation Monitor, Model 25540 with an electric (E) field probe. Model 8644 and a magnetic (H) field probe, Model 8635. The geometric mean of the maximum measured exposures was at least 200 V/m for the E-field and 0.094 A/m for the H-field. The Occupational Safety and Health Administration (OSHA) exposure standard for RF radiation in the range of 10--100,000 MHz is 10 mW/cm2 as averaged over any 0.1-hour period. This value corresponds to an exposure of 200 V/m for the E-field and 0.5 A/m for the H-field. NIOSH found that 55% of the heat sealer operators were exposed to levels for the E-field above 200 V/m; for the H-field, 21% of the operators were exposed to levels above 0.5 A/m. For the heat sealers evaluated, the frequencies ranged from 18 to 31 MHz. On the basis of these environmental data, RF heat sealer operators experience a wide range of exposures both above and below the OSHA standard. The exposure range is sufficiently broad to make these operators adequate candidates for epidemiologic study.

Environmental Exposure↗
PubMed1982

Changed prognosis of breech-presenting low birthweight infants.

We have compared the mortality and morbidity of low birthweight breech-presenting singleton infants born in the Coventry Maternity Hospital during the years 1973 and 1974 with those born during 1979 and 1980. During this period changes in management have included an increase in the caesarean section rate and the continuing development of methods of intensive care for the newborn infants. The neonatal mortality rate has fallen but the increased survival rate is accounted for largely by the survival of handicapped infants. The value of routine caesarean section in the absence of other obstetric pathology for low birthweight breeches is unproven and may be deleterious to mother and baby.

Breech Presentation↗
PubMed1982

Lysine vasopressin in Alzheimer disease.

The effects of lysine vasopressin on memory and cognitive deficits in Alzheimer disease was investigated. In a double-blind study, seven patients were given 16 units of lysine vasopressin per day for 10 days and were compared with seven different patients receiving placebo. No significant difference in performance between the vasopressin and placebo-treated groups was found in tests designed to evaluate learning, memory, and perception. However, significantly greater improvement in reaction time was seen in the vasopressin-treated group, although this effect was delayed and may have been contributed to by factors other than drug activity.

Alzheimer Disease↗
PubMed1981

A randomized trial comparing surgical adrenalectomy with aminoglutethimide plus hydrocortisone in women with advanced breast cancer.

We randomized 96 postmenopausal women with metastatic breast carcinoma to receive surgical adrenalectomy or medical therapy with an adrenal inhibitor, aminoglutethimide (AG), plus replacement hydrocortisone. Before randomization, women were stratified according to disease-free interval, site of dominant disease, and estrogen-receptor status. Of 40 evaluable women treated with AG and hydrocortisone, 53 per cent had objective responses, as compared with 45 per cent of 29 women undergoing surgical adrenalectomy (P value not significant). Responses lasted a mean of 17.2 months in the medical group and greater than 17.1 months in the surgical group (not significant). Estrogen levels fell similarly in response to either treatment, whereas AG and hydrocortisone preserved androgen production. A null hypothesis tested the single question asked by this study: "Is surgical adrenalectomy superior to treatment with AG and hydrocortisone?" Rejection at significance levels of P = 0.01 and P = 0.07 for differences of 20 per cent and 10 per cent, respectively, suggested that medical therapy with AG and hydrocortisone may be logically chosen in place of surgical adrenalectomy.

Adrenalectomy↗