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Biomedical subjects

L M Scott

Publications and source records attributed to L M Scott.

At least 37 records · Page 2Linked to original sources
PubMed1991

A radiological evaluation of phosphogypsum.

Phosphogypsum is the by-product resulting from phosphoric acid or phosphate fertilizer production. The phosphate are used in these chemical processes contains the naturally occurring radioactive material U and all its subsequent decay products. During processing, the U generally remains in the phosphoric acid product, while the daughter, 226Ra, tends to be concentrated in the phosphogypsum. Phosphogypsum has physical properties that make it useful as a sub-base for roadways, parking lots, and similar construction. A radiological evaluation, to determine exposures to workers mixing this material with a stabilizing agent (portland cement), was performed at a South Louisiana phosphoric acid chemical plant. Measurements of the 226Ra content of the phosphogypsum showed an average of 1.1 +/- 0.3 Bq g-1 (0.7-1.7 Bq g-1). The average measured gross gamma exposure rate on the phosphogypsum pile corresponded to a dose equivalent rate of 0.368 +/- 0.006 mu Sv h-1 (0.32-0.42 mu Sv h-1). Radon daughter concentrations measured on top of the phosphogypsum pile ranged from 0.0006 to 0.001 working levels. An analysis of the airborne 226Ra concentrations showed only background levels.

Bismuth↗
PubMed1990

Major trauma in pregnant women: maternal/fetal outcome.

One regional trauma center's experience with a large number of seriously injured pregnant women was reviewed to identify factors affecting maternal and fetal outcome after injury. Of 318 pregnant women who suffered trauma from January 1984 through December 1988, 25 (8%) were severely injured and would have required hospital admission even in the absence of pregnancy. Physical examination, except for the inappropriate absence of fetal heart tones, was a poor predictor of fetal status. Sonography proved to be the most accurate modality for acutely assessing fetal status. There was one (4%) maternal death, consistent with predicted mortality (TRISS methodology). Four pregnancies were lost and one neonate died because of injuries sustained, not because of surgery or anesthesia. There was significant difference between the ISS (average, 9) and CTS (average, 16) of women with surviving pregnancies or successful deliveries and the ISS (average, 30) and CTS (average, 12) of women who lost pregnancies or witnessed neonatal death. Fetal outcome relates to direct fetal injury and to the acute hemodynamic insult associated with maternal trauma. Maternal evaluation and treatment should occur in a stepwise and organized fashion following the general principles of trauma care (ATLS guidelines) in conjunction with perinatal specialists. Uterine ultrasonography should be an integral component of the initial evaluation. With expedient resuscitation, evaluation, and intervention, maternal and fetal survival can be expected.

Adolescent↗
PubMed1987

Pregnancy following induced abortion: maternal morbidity, congenital abnormalities and neonatal death. Royal College of General Practitioners/Royal College of Obstetricians and Gynaecologists Joint Study.

In a prospective cohort study of the long-term sequelae of induced abortion, a comparison is made between a group of 6418 women who had an induced abortion (cases) and a control group of 8059 women recruited with an unplanned pregnancy which was not terminated with an induced abortion (controls). The present paper reports on 729 cases and 1754 controls who had a post-recruitment pregnancy. In general, prior induced abortion had no material effect on the rate of pregnancy-related morbidity, nor on the rate of congenital abnormalities and neonatal death in the offspring. There was, however, a significant difference in two specific conditions. In the post-index pregnancy in the cases there was an increased relative risk (RR 2.26) of the occurrence of urinary tract infection and a decreased risk (RR 0.25) of pregnancy-related anaemia.

Abortion, Induced↗
PubMed1985

Benzene exposure in the United States 1978-1983: an overview.

Due to the interest in reducing the benzene exposure limit from 10 to 1 ppm, the benzene exposure data collected since 1977 were compiled and evaluated. Some 38,000 data points representing either time-weighted air samples or persons exposed were collected from five industries which produce and/or use benzene and two government organizations. Of the reported data, 87% represented exposure levels of 1.0 ppm or less. Petroleum and chemical operations where elevated exposure levels were reported included petrochemical and bulk loading operations. Benzol and by-product plants in the iron and steel industry showed similar elevated results.

Air Pollutants, Occupational↗
PubMed1985

Cholesterol metabolism: regulatory effects of the vagus in the normal and diabetic animal.

The activities of beta-Hydroxy-beta-methylglutaryl CoA reductase (HMG CoA reductase), Acyl CoA: Cholesterol-O-acyltransferase (ACAT) and cholesterol 7 alpha-hydroxylase, the major enzymes involved in cholesterol metabolism, were determined in diabetic and non-diabetic rats after vagotomy and compared with those of sham-operated controls. Hepatic cholesterol levels and serum lipid profiles were also examined. In the non-diabetic animals vagotomy produced a significant increase in HMG CoA reductase (the rate limiting enzyme of cholesterol biosynthesis), and ACAT (the enzyme responsible for intracellular esterification) activities, while the activity of cholesterol 7 alpha-hydroxylase (which catalyses the rate determining step of bile acid biosynthesis) was significantly decreased. These rats had higher levels of free and esterified cholesterol in the liver and serum cholesterol levels were also increased in comparison with sham-operated animals. Vagotomized diabetic rats had similar HMG CoA reductase activity, but significantly reduced ACAT and reduced cholesterol 7 alpha-hydroxylase activity in comparison with sham-operated diabetic rats. There were significant alterations in hepatic and serum cholesterol fractions in both normal and diabetic rats after vagotomy. The results suggest that vagotomy leads to an increased rate of cholesterol synthesis and a decreased rate of cholesterol utilization, thus providing a possible mechanism for excessive cholesterol accumulation. These results are discussed in relation to alterations in cholesterol metabolism found in diabetic autonomic neuropathy.

Animals↗
PubMed1983

Changes in hepatic and intestinal cholesterol regulatory enzymes. The influence of metformin.

The effect of metformin (N,N-dimethylbiguanide) on the rate-limiting enzymes of cholesterol metabolism was observed. 3-Hydroxy-3-methylglutaryl-CoA reductase (HMG-CoA reductase) and acyl-CoA-cholesterol acyltransferase (ACAT) activities were estimated in hepatic microsomal and intestinal cell preparations from normal and alloxan-diabetic rats. Metformin administration had no effect on either hepatic enzyme. Intestinal ACAT activity was significantly decreased in the metformin-treated rats when compared with controls (P less than 0.001). Intestinal HMG-CoA reductase activity was not significantly affected. Diabetic rats showed a significantly higher intestinal HMG-CoA reductase activity when compared with controls (P less than 0.001). Intestinal ACAT activity in the diabetic group was similar to control values. Metformin administration to diabetic rats caused a marked decrease in both intestinal HMG-CoA reductase activity (P less than 0.001) and ACAT activity (P less than 0.002). It is concluded that the effect of metformin on the intestinal cholesterol enzyme system may be responsible for its cholesterol-lowering action.

Acyltransferases↗