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Biomedical subjects

N White

Publications and source records attributed to N White.

At least 109 records · Page 6Linked to original sources
PubMed1985

Severe Chlamydia psittaci sepsis in pregnancy.

Two patients with severe chlamydial sepsis in pregnancy are described and compared with previously published case reports. The infections appear to have been zoonotic, the patients acquiring their infections as a result of exposure to enzootic abortion of ewes. This is an important but poorly recognised human infection which because of its severity in pregnancy deserves consideration in patients with an appropriate occupational history.

Adult↗
PubMed1984

Modified Forssell's operation for crib biting in the horse.

Thirty-five horses with a history of crib biting or wind sucking were treated with a modification of the Forssell procedure. The technique involved bilateral neurectomy of the ventral branch of the accessory nerve combined with excision of a portion of the omohyoideus, sternohyoideus, and sternothyroideus muscles. Twenty horses became free of the vice, while in 11 there was a noticeable reduction in frequency of the vice. Four horses returned to crib biting/wind sucking at the same intensity as before surgery. The observation time following each operation was at least 12 months. Complications from wound healing were minimal, and cosmetic results were considered excellent in most horses. It was concluded that this modified surgical procedure produced a better result than neurectomy alone, without the disfigurement of Forssell's procedure.

Accessory Nerve↗
PubMed1984

In vivo chloroquine-induced inhibition of insulin degradation in a diabetic patient with severe insulin resistance.

We report on a 26-yr-old patient with an 11-yr history of insulin-dependent diabetes mellitus who exhibited insulin resistance with a requirement of up to 15,000 U of intravenous (i.v.) insulin/day. Attempts to diminish her insulin requirement by administration of sulfated insulin or Trasylol were unsuccessful, with the patient remaining resistant to subcutaneous (s.c.) and i.v. administration of pure pork insulin. Chloroquine phosphate therapy (500 mg twice a day) resulted in a decreased requirement for i.v. insulin (700 U/day as compared with the pretreatment requirement of 8400 U/day). Accelerated insulin degradation in s.c. fat tissue of the patient before treatment with chloroquine was demonstrated. This activity was decreased by 64% during chloroquine therapy. Inhibition of insulin degrading activity (IDA) during chloroquine therapy was associated with reductions in the leukocyte lysosomal enzymes alpha-galactosidase and hexosaminidase-A but not hexosaminidase-B and beta-glucuronidase. This study constitutes the first reported use of chloroquine for treatment of insulin resistance as a result of accelerated insulin degradation, and it provides evidence of the effectiveness of this agent in this rare condition.

Adipose Tissue↗
PubMed1983

Critical review of international standards for respiratory protective equipment - I. Respiratory protective equipment for particulate-laden atmospheres.

The standards for respiratory protective equipment (R.P.E.) from eleven countries and standards organizations were grouped according to type as particulate removing, gas and vapor removing, airline (fresh air hose and compressed air types), and self-contained breathing apparatus (open circuit and closed circuit). Each group of standards was further divided into specification and performance requirements. This paper is one in a series of three that highlights and critically reviews international respirator standards; it deals specifically with R.P.E. for protection against particulate-laden atmospheres. Great Britain, Australia, European Committee for Standardization (CEN), France, South Africa, Italy, Spain, New Zealand, Scandinavia, Japan, and Germany have standards for R.P.E. against particulate-laden atmospheres. Tabular summaries and accompanying discussion of national requirements are presented in the following categories: solid and liquid aerosol removal efficiency, clogging, and rough usage. Large differences and some notable omissions exist among standards. For example, the protection capacity of the filter can be tested by using solid particulate or liquid challenge aerosols. The majority of the countries evaluate protection capacity using solid particulate aerosols, while the remainder use both solid and liquid or liquid aerosols only. Other differences in filter testing deal with the composition of the test aerosol and the characteristic of the filter measured. The initial penetration or the penetration of the filter as it is being loaded over a specified period of time can be measured. In the latter case penetration is averaged over the test period and the degree of protection is assessed only for that overall time period; information is not provided concerning the protection afforded by the filter in the earlier stages of use.

Aerosols↗
PubMed1983

Critical review of international standards for respiratory protective equipment - II. Gas and vapor removal efficiency and fit testing.

The purpose of a Respiratory Protective Equipment (R.P.E.) standard is to assure that a minimum level of performance is reached by the respirator. Standards from a number of countries and standards organizations require that certain specifications are met in construction and that respirators be evaluated by specific performance tests. This is the second of three critical review papers related to respirator standards. We here summarize in tabular form, compare and critically review how the different countries or standards organizations test respirators designed for protection against gases and vapors for leakage due to improper fitting of the respirator facepiece and gas and vapor removal efficiency of the cartridge/canister. Two general aspects as they relate to removal capacity testing are discussed. The first issue deals with the selection of test gases and vapors that best represent the sorptive behavior of a class or group of compounds. The second issue deals with the extrapolation of laboratory testing under rigidly specified conditions to conditions of actual use. Fit testing varies from country to country. The fit testing conditions specified in the various standards are summarized along with a discussion of test material selection, the test panel selection, and the range of controlled test activities.

Air Pollutants, Occupational↗
PubMed1983

Critical review of international standards for respiratory protective equipment - III. Practical performance tests.

This paper, the third in a series of papers devoted to review of international standards for Respiratory Protective Equipment (R.P.E.), summarizes in tabular form, compares, and critically reviews standards of different countries or organizations pertaining to practical performance tests (Man Tests). There are similarities, differences and omissions in the national standards that deserve attention. Of the countries or organizations that require Man Tests on particulate and/or gas and vapor respirators, none described in detail the tests to be performed. For example, CEN requires that Man Tests be conducted on gas/vapor respirators under realistic conditions to determine imperfections that cannot otherwise be determined by other performance tests, but does not stipulate the testing procedure. With respect to fresh-air hose, compressed-air line and self-contained breathing apparatus R.P.E., only Great Britain and CEN present specific Man-testing requirements in detail. Man Tests for all types of R.P.E. have a specific purpose: to determine any imperfections in, or malfunction of the apparatus under simulated work conditions. One major difference, however, is in the kind of work simulation activities required. In the testing of fresh-air hose and compressed-air line respirators, for instance, CEN describes in great detail, a variety of activities to be conducted. Great Britain merely states that the subjects shall work in practical conditions. Another important disparity relates to the conditions under which the test is to be performed. For example, CEN requires a heavy-duty test and a cooled chamber test, as well as tests under normal and low temperature conditions. Great Britain, on the other hand, requires only the latter two tests. Still other differences lie in the kinds of medical surveillance required during testing and the evaluation criteria used for assessment.

Air Pollutants, Occupational↗
PubMed1982

Prevalence of hypertension in semi-skilled manual workers.

This study demonstrates a high prevalence of hypertension (43,9%) in a population of unskilled manual workers. No differences were detected in the prevalence rates for two ethnic groups. The importance of age standardization for comparison of data with other studies of an age-linked phenomenon such as hypertension is stressed. Blood pressure was higher in workers who had worked their daily shift than in those who had not worked a shift. These findings might be explained by means of an hypothesis linking stress at work with hypertension. The literature relevant to this hypothesis is outlined.

Adult↗
PubMed1982

Effect of serotonin depletion induced by p-chloroamphetamine on changes in rats' activity levels-produced by lithium.

The role of serotonin (5-HT) transmission in the production of changes in rats' activity levels induced by 0.15 and 1.50 mEq/kg LiCl was assessed by selectively depleting 5-HT brain levels with p-chloroamphetamine prior to chronic administration of LiCl for 21 days. While p-chloroamphetamine pretreatment decreased 5-HT levels by 56%, irrespective of the fact that the animals had been administered either saline, 0.15, or 1.50 mEq/kg LiCl for 21 days, it did not alter the effects that each LiCl dose alone that on activity levels. Both LiCl administrations produced an 18% increase in 5-HT levels in rats pretreated with saline, yet diametrically opposed effects on activity levels. A parallel is drawn between these biochemical findings and previously reported data indicating that both LiCl doses produce an improvement in selective attention, yet opposed effects on rats' activity levels. The hypothesis that 5-HT transmission might be crucially involved in mediating the dose-independent effect of lithium on selective attention is proposed for future research.

Amphetamines↗