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Biomedical subjects

S Evans

Publications and source records attributed to S Evans.

At least 307 records · Page 17Linked to original sources
PubMed1985

Clearance of 3H-dopamine from the amniotic fluid in the rhesus monkey.

Previous studies have suggested that dopamine is the major catecholamine in the amniotic fluid; however, there are few data available concerning the metabolism of this hormone in the amniotic fluid compartment. With the use of acute 3H-dopamine injection studies into the amniotic sac of pregnant rhesus monkeys, the dopamine half-life was observed to be 29 minutes, the amniotic fluid volume was 113 ml, the metabolic clearance rate was 164 ml/hr, and the calculated production rate was 436 ng/hr. The biphasic pattern of dopamine clearance from this compartment suggests that it is cleared from the amniotic sac by mechanisms similar to those used in the intravascular compartment.

Amniotic Fluid↗
PubMed1985

Challenges facing the distribution of an artificial-intelligence-based system for nursing.

The marketing and successful distribution of artificial-intelligence-based decision-support systems for nursing face special barriers and challenges. Issues that must be confronted arise particularly from the present culture of the nursing profession as well as the typical organizational structures in which nurses predominantly work. Generalizations in the literature based on the limited experience of physician-oriented artificial intelligence applications (predominantly in diagnosis and pharmacologic treatment) must be modified for applicability to other health professions.

Attitude of Health Personnel↗
PubMed1985

Promoter activity and transcript mapping in the regulatory region for genes encoding ribosomal protein S15 and polynucleotide phosphorylase of Escherichia coli.

The genes encoding ribosomal protein S15 (rpsO) and polynucleotide phosphorylase (pnp) occupy adjacent positions and are oriented in the same direction on the Escherichia coli chromosomes. The nucleotide sequence of the region controlling the expression of these two genes has been determined. Two in-phase gene fusions between pnp and lacZ were constructed. The fusions define the translational reading frame of the pnp gene and indicate that the expression of pnp is independent of the upstream rpsO gene. Transcript mapping with nuclease S1 demonstrated that the two genes are transcribed from separate promoters and that the rpsO-pnp intergenic space contains a strong transcriptional terminator. The transcriptional start points have been localized.

Amino Acid Sequence↗
PubMed1985

Isolated late asthmatic reaction due to nickel sulphate without antibodies to nickel.

A worker with occupational exposure to nickel developed asthma a few months after starting work. Skin prick tests to nickel sulphate were negative. Inhalation challenge with nickel sulphate, at a concentration of 10 mg/ml for 30 min induced a late asthmatic reaction, starting 3 hr after the end of exposure leading to severe nocturnal attack. Tests for antibodies with nickel reactivity were negative.

Adult↗
PubMed1985

Prevalence and disabilities in 4 to 8 year olds with cerebral palsy.

A register of children born between 1970 and 1979 in the South East Thames Regional Health Authority, and diagnosed as having pre-, peri-, and postnatal cerebral palsy, was set up between 1978 and 1981. We report the 527 children born between 1970 and 1974 for whom ascertainment is virtually complete. The estimated prevalence was 2.2 per 1000, with 7.4% multiple births, and 58% boys. Birthweight distribution is as expected, with 35% weighing less than 2500 g at birth. Parental permission for release of detailed medical information was sought, and the clinicians responsible gave us data on the type of cerebral palsy; details of impairments, disabilities, and anticipated future prospects; and an opinion on the probable timing of the cause. There was a high incidence of orthopaedic defects which must represent a considerable use of resources, although the prevalence of hearing and vision defects suggested that some of these may be undetected.

Age Factors↗
PubMed1985

Effect of sodium valproate on subcellular fraction enzymes in rat liver.

Previous observations that valproic acid (VPA) causes hepatic damage prompted us to investigate the effect of large doses of the drug (0.6, 1.2 and 1.8 mmol/kg/day) on a number of liver enzymes located on different subcellular fractions. In mitochondria, glutamate dehydrogenase, aspartate aminotransferase and ornithine carbamoyltransferase were significantly increased (1.8 mmol/kg/day). In microsomes, gamma-glutamyltransferase activity increased significantly (1.8 mmol/kg) and cytochrome P-450 content decreased significantly (1.2 and 1.8 mmol/kg). In cytosol, both aspartate and alanine aminotransferase activities were increased at all dose levels. These results indicate that VPA induces dose-dependent changes in some liver enzyme activities.

Animals↗
PubMed1985

Adherence of Candida to corneal surface.

In the pathogenesis of mycotic infections, adherence of the microbes to surface structures prior to invasion appears to be the initial and essential step in a susceptible host. Adherence and inhibition of adherence of Candida albicans to rabbit corneal surface was investigated in vitro by light and scanning electron microscopic examinations. The results indicate that blastospores of Candida albicans rarely bind to intact corneal epithelium, but consistently adhere to stroma denuded of epithelium. Such adherence was inhibited by concanavalin A. With its strong affinity for the yeast cell wall carbohydrate mannan, concanavalin A may block the site of attachment of yeast cells to the corneal surface.

Animals↗
PubMed1985

Computer literacy in family medicine.

Computer literacy is justified and defined in terms of core knowledge about fundamental problem-solving methods for information processing (not as computer languages, hardware characteristics, and so on). These core principles provide a solid grounding that will remain essentially applicable and valid over time. Some of the most powerful methods are used to create expert systems applications, simulations, and database management systems.

Artificial Intelligence↗
PubMed1985

Decision support systems for the outpatient office. Two examples of medical expert systems.

Although definitive decision-making systems remain beyond the scope of present-day applications available on the market, effective and efficient decision support systems have been developed and are entering the market place. These systems focus on very specific tasks in limited domains and can be valuable adjuncts in primary care settings. There are also a few large-scale applications with well-defined goals that have proved themselves. It is imperative to validate the organizational support and expertise underlying any expert decision support system.

Ambulatory Care↗
PubMed1985

The efficacy of internal iliac artery ligation in obstetric hemorrhage.

During 1966 to 1982, 18 patients with severe obstetric hemorrhage underwent hypogastric artery ligation at our institution. Eight of 14 patients or 57 per cent (excluding three pregnancies which were terminated and a planned cesarean hysterectomy) had failed hypogastric artery ligations necessitating hysterectomy. Placenta accreta accounted for six patients of whom three required a hysterectomy. Uterine laceration was the second largest cause of hemorrhage in five patients, all of whom required a hysterectomy after hypogastric artery ligation failed. Hypogastric artery ligation does have a specific role in the management of obstetric hemorrhage, but it is not without substantial risk of failure. The obstetrician should carefully weigh whether or not the patient can undergo a more conservative procedure at the expense of a delay in the definitive treatment of hemorrhage. The instances presented herein should aid the clinician in deciding what is appropriate management for acute obstetric hemorrhage.

Acute Disease↗
PubMed1984

Donor origin of the in vitro hematopoietic microenvironment after marrow transplantation in mice.

Bone marrow stroma from radiochimeric mice was established in culture. The polymorphic enzyme glucose phosphate isomerase (GPI) was used to determine the proportions of donor and recipient present in the original bone marrow and in cultured stroma. Bone marrow initially containing 95% donor GPI, when cultured and subsequently passaged for up to 8 weeks remained about 70% donor GPI. We conclude that many cultured stromal cells are donor derived in our radiochimeras and these are probably of hematopoietic origin.

Animals↗
PubMed1984

Implementation of a computer-based test generator to evaluate health professions continuing education.

A variety of artificial-intelligence-based expert medical systems have been adapted to evaluate a learner's performance in the information areas in which the systems are expert. This paper describes a similar adaptation of a computer-based health sciences tutor (called the COMMES system). The Evaluation Consultant system to be described adapts the COMMES system to become a test generator. This computer-based consultant generates tests entirely on its own, covering programs of study that the COMMES system previously constructed to satisfy a user's identified needs. A health professional is awarded continuing education credits after (1) finishing a study unit constructed by COMMES and (2) completing successfully a test created by the Evaluation Consultant. This system is being implemented in several test sites and has significant advantages for the support of continuing education, especially in rural or isolated areas.

Computer-Assisted Instruction↗
PubMed1984

Repair of fractionated radiation in plateau phase cultures of human tumor cells and human multicellular tumor spheroids.

We have measured potentially lethal damage repair (PLDR) after fractionated radiation, delivered at 24-h intervals in density-inhibited plateau phase cultures of four human tumor cell lines derived from tumors of differing radiocurability (two melanoma and two breast). The repair of potentially lethal damage conferred significant radioresistance on the human melanoma cells but not on the breast carcinoma cells. We examined the effects of fractionated radiation on human tumor cells adapted to become multicellular tumor spheroids (MTS). MTS derived from a human neuroblastoma were "cured" by a total fractionated radiation dose about 50% of that required for MTS derived from a human melanoma.

Breast Neoplasms↗
PubMed1984

Oral contraceptive use and malignant melanoma in Australia.

In a case control study of 287 women aged 15-24 years with malignant melanoma and 574 matched controls, findings relating to oral contraceptive use and other hormone use are reported. Ever having used oral contraceptives was not associated with an increased risk of melanoma (relative risk for ever use of the pill = 1.0). Women with melanoma were, however, more likely to have taken oral contraceptives for long periods of time in the past, the relative risk associated with oral contraceptive use for a total duration of 5 years or longer which had begun at least 10 years before the melanoma was diagnosed being 1.5 (95% confidence interval 1.03 to 2.14) This elevated risk persisted after controlling for the reported hair and skin colour, frequency of moles on the body, place of birth, and measures of sunlight and fluorescent light exposure. Cases were more likely than controls to have used hormones to regulate their periods, hormonal replacement therapy and be given hormone injections to suppress lactation, the respective relative risks being 1.9, 1.4 and 1.4, but none differed significantly from 1.0. These findings suggest that prolonged oral contraceptive use may, after a lag of 10 years or so, increase the risk of malignant melanoma.

Adolescent↗
PubMed1984

Outpatient use of oral rehydration solutions in Apache population: effect of instructions on preparation and contamination.

Oral Rehydration Solutions (ORS) containing 90 and 50 mmol/L sodium have recently been recommended for use in ambulatory children in the U.S. These solutions are now marketed in powder form by some commercial companies. However, few data are available in the U.S. on the accuracy with which the solutions are mixed at home or on the bacterial contamination that may occur during mixing. We evaluated the effect of various forms of instructions on the occurrence of bacterial contamination and accuracy of mixing ORS at home by mothers of patients who were dispensed the dry ingredients of an ORS containing 90 mmol/L sodium at the U.S. Public Health Service Hospital, Whiteriver, Arizona. Patients were randomized to one of the four following groups: group I (23 patients) was given written instructions for mixing the solution along with a pre-marked container; group II (22 patients) was given written instructions only; group III (22 patients) was given a premarked container only; and group IV (19 patients) was given neither. All patients were given oral instructions in the preparation of ORS and were asked to refrigerate the reconstituted ORS. We collected samples of ORS at the patient's home 1 day after the clinic visit, to measure their electrolyte content and to identify any bacterial contamination. Mean Na+ concentrations were significantly lower in the ORS prepared by mothers/guardians in groups that were not given a premarked container [82 +/- 13 (II) and 79 +/- 21 (IV) mmol/L vs. 88 +/- 13 (I) and 92 +/- 14 (III) mmol/L; p less than 0.01].(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1984

Reproductive status of adult daughters in family groups of common marmosets (Callithrix jacchus jacchus).

Urine samples were collected from 6 pubertal female common marmosets at approximately 3-day intervals over a period of 3-7 months. All 6 females were the eldest daughters in their family groups. 3 of these females were subsequently removed from their families and sampled in isolation for another 2-3 months. Levels of urinary pregnanediol-3 alpha-glucuronide were measured by radioimmunoassay in order to establish whether these females showed ovarian cyclicity. No cyclical fluctuations in the levels of pregnanediol were observed in the females housed with their families even though the females were of a reproductively mature age. Cyclicity was quickly established (within 18-22 days) when the females were removed from the family. These results are discussed in the light of similar recent investigations on callitrichid reproduction and the behavioural implications are considered.

Animals↗
PubMed1984

Ulcerative colitis: why is the mortality from cardiovascular disease reduced?

A recent mortality study of patients with ulcerative colitis showed significant deficits in deaths from cardiovascular disease and from respiratory disease in males. The reasons for the observed deficits have been examined by studying the risk factors in a consecutive series of 103 patients with ulcerative colitis using matched controls. The patients and controls were assessed for age, sex, social class, alcohol and tobacco consumption. Height, weight and blood pressure were recorded and fasting blood samples were taken for serum lipid estimation. Patients with ulcerative colitis had significantly lower systolic and diastolic blood pressures and the changes were particularly marked in patients with extensive colitis and after panproctocolectomy. After matching for age, sex and social class the patients with ulcerative colitis smoked significantly less than controls. Serum lipid measurements were similar in both groups. The lower blood pressure may be related to sodium and water depletion particularly in ileostomy patients and those with extensive colitis.

Adult↗