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Biomedical subjects

J G Bell

Publications and source records attributed to J G Bell.

At least 37 records · Page 2Linked to original sources
PubMed1996

Dietary lipid affects phospholipid fatty acid compositions, eicosanoid production and immune function in Atlantic salmon (Salmo salar).

Atlantic salmon (Salmo salar) post-smolts were fed diets containing either Fosol (FO), a North Sea fish oil, sunflower oil (SO), linseed oil (LO) or Marinol K (MO), a southern hemisphere fish oil rich in 20:5(n-3) for 12 weeks. A macrophage-enriched leucocyte preparation was obtained from head kidney and the fatty acid compositions of the individual membrane phospholipids measured. In general phospholipids from SO- and LO-fed fish had increased 18:2(n-6), 20:2(n-6) and 20:3(n-6) compared to the fish oil treatments while LO-fed fish had lower 20:4(n-6) than any other dietary treatment. Fish fed LO also had increased 18:3(n-3), 18:4(n-3), 20:3(n-3) and 20:4(n-3). The 20:5(n-3) content of kidney macrophage-enriched leucocyte phospholipids was highest in MO-fed fish followed by FO- and LO-fed fish with the lowest level in fish fed SO. The overall effect on the ratio of eicosanoid precursors, 20:4/20:5, showed the highest value in SO-fed fish and the lowest in fish fed LO. Production of LTB5 by kidney macrophage-enriched leucocytes stimulated with A23187 was highest in MO-fed fish and lowest in those fed SO. Production of LTB4 was greatest in SO-fed fish and lowest in fish fed LO. Serum Ig levels were significantly affected by dietary treatment with highest values in fish fed FO and SO and lowest in fish fed MO and LO.

Animals↗
PubMed1995

Diets rich in eicosapentaenoic acid and gamma-linolenic acid affect phospholipid fatty acid composition and production of prostaglandins E1, E2 and E3 in turbot (Scophthalmus maximus), a species deficient in delta 5 fatty acid desaturase.

Duplicate groups of juvenile turbot, (Scophthalmus maximus), were fed diets containing either Marinol K (MO), a marine fish oil rich in eicosapentaenoic acid (EPA; 20:5, n-3) or borage oil (BO), rich in gamma-linolenic acid (GLA; 18:3, n-6), for a period of 12 weeks. Individual phospholipid fatty acid compositions from hearts of fish fed BO had significantly more 18:2, n-6, GLA, 20:2, n-6, dihomo-gamma-linolenic acid (DHGLA; 20:3, n-6) and total n-6 polyunsaturated fatty acids (PUFA), but significantly less arachidonic acid (AA; 20:4, n-6), compared to fish fed MO. In both phosphatidylcholine (PC) and phosphatidylethanolamine (PE) from heart, the DHGLA was increased by over 50-fold in fish fed BO while AA was reduced by over two-thirds, compared to fish fed MO. In brain, EPA was the major C20 PUFA, i.e. potential eicosanoid precursor in all phospholipids from fish fed MO, with the EPA level being twice that of AA in brain phosphatidylinositol (PI). DHGLA was the major C20 PUFA in all phospholipid classes from fish fed BO. In kidney and gill, EPA was the predominant C20 PUFA in all phospholipid classes, except PI, in fish fed MO. In kidney of fish fed BO, DHGLA was the major C20 PUFA in all phospholipid classes, except PE. In gill of fish fed BO, DHGLA was the major C20 PUFA in all phospholipid classes, including PI, where DHGLA was over 2.5-fold greater than AA. In homogenates of heart, kidney and gill from BO-fed fish the prostaglandin E1 (PGE1) concentration was significantly increased compared to MO-fed fish. In heart and kidney homogenates from fish fed MO the PGE3 concentration was significantly increased compared to fish fed BO. The ratio of PGE2/PGE1 was significantly reduced in brain, heart, kidney and gill homogenates from fish fed BO compared to those fed MO.

8,11,14-Eicosatrienoic Acid↗
PubMed1995

A systematic approach to health surveillance in the workplace.

This paper reviews the range of health surveillance activities which can be utilized in the workplace by occupational health professionals for assessing fitness for work and contributing to the prevention of occupational illness and promotion of good health. The systematic approach described categorizes health surveillance procedures into occupational or non-occupational, risk-based or unfocused, and as primary, secondary or tertiary preventive measures. All categories of health surveillance are currently being practised to some extent, but the type of surveillance may not match the needs of the workplace in some situation. In order to aid health professionals in deciding which procedures should be implemented, recommendations based on an assessment of health risks are made. The key proposal is to establish a minimum level of periodic health surveillance for all workers based on a targeted lifestyle health risk assessment and a structured health questionnaire. Additional procedures can then be added sequentially as appropriate to manage any health risks in the workplace. The role of the unfocused periodic general medical examination is discussed in the context of the systematic approach and allows occupational professionals to critically appraise its usefulness.

Health Promotion↗
PubMed1994

Effect of supplementation with 20:3(n-6), 20:4(n-6) and 20:5(n-3) on the production of prostaglandins E and F of the 1-, 2- and 3-series in turbot (Scophthalmus maximus) brain astroglial cells in primary culture.

The production of prostaglandins E and F of the 1-, 2- and 3-series was determined in primary cultures of turbot (Scophthalmus maximus) brain astroglial cells after supplementation with 25 microM dihomo-gamma-linolenic (20:3(n-6)), arachidonic (20:4(n-6)) and eicosapentaenoic (20:5(n-3)) acids. Supplementation by 20:3(n-6), 20:4(n-6) and 20:5(n-3) for 4 days significantly increased the percentages of the respective acids in the total cellular lipid of the turbot astrocytes. The predominant prostaglandins formed by turbot astrocytes in response to stimulation with calcium ionophore A23187 were prostaglandin E2 and prostaglandin F2 alpha under all experimental conditions. The production of prostaglandin E2 was stimulated 2.6-fold, but prostaglandin F2 alpha production was unaffected after supplementation of cultures with 20:4(n-6). However, prostaglandin E2 production in astrocytes was significantly inhibited 3- and 4-fold, and prostaglandin F2 alpha was inhibited 1.6- and 14.6-fold by supplementation with 20:3(n-6) and 20:5(n-3), respectively. Supplementation with 20:3(n-6) also significantly increased the production of prostaglandin E1 (almost 4-fold) and prostaglandin F1 alpha (2.2-fold) whereas supplementation with 20:5(n-3) did not significantly increase the production of prostaglandin E3. Prostaglandin F3 alpha but not prostaglandin E1 were significantly reduced in 20:5(n-3)-supplemented cultures.

Animals↗
PubMed1994

Pregnancy outcome following Mustard procedure for transposition of the great arteries: a report of five cases and review of the literature.

OBJECTIVE: To review outcomes and complications of pregnancies in women with transposition of the great arteries who had undergone the Mustard procedure. METHODS: Four women with transposition of the great arteries who had undergone Mustard procedures in childhood received their obstetric care for five pregnancies at three institutions in the greater Philadelphia area between 1990-1992. Pregnancy complications and outcomes were reviewed. RESULTS: The most common maternal complication in pregnancy following performance of the Mustard procedure was cardiac arrhythmia, which required treatment in two of four patients. Late-onset fetal growth restriction requiring induction occurred in two of five pregnancies. Third-trimester oligohydramnios requiring induction occurred in one patient, and her second pregnancy was complicated by preterm labor and premature rupture of the membranes (PROM) at 33 weeks. One patient with a twin pregnancy developed mild preeclampsia, preterm labor, and PROM at 30 weeks. There were no neonatal or perinatal deaths or significant morbidity. CONCLUSION: If a patient with transposition of the great arteries who underwent the Mustard procedure is hemodynamically stable before pregnancy, good maternal and fetal outcome can be expected.

Adolescent↗
PubMed1993

Dietary sunflower, linseed and fish oils affect phospholipid fatty acid composition, development of cardiac lesions, phospholipase activity and eicosanoid production in Atlantic salmon (Salmo salar).

Atlantic salmon (Salmo salar) post-smolts were fed practical-type diets in which the lipid was supplied either as fish oil (FO), sunflower oil (SFO) or linseed oil (LO) for 12 weeks. In general, the heart phospholipids from SFO-fed fish had increased 18:2n-6, 20:2n-6, 20:3n-6 and 20:4n-6 but decreased 20:5n-3 compared to both other dietary treatments. This was reflected in a decreased n-3/n-6 polyunsaturated fatty acid (PUFA) ratio and an increased 20:4n-6/20:5n-3 or eicosanoid precursor ratio in SFO-fed fish. While heart phospholipids of fish fed LO had increased levels of 18:2n-6, 20:2n-6 and 20:3n-6 compared to fish fed FO, 20:4n-6 levels were reduced, although only significantly in phosphatidylcholine (PC). Dietary-induced changes in phospholipid fatty acid compositions of blood leucocytes were similar to those in heart, although fish fed LO had increased 20:5n-3 compared to fish fed FO. Thromboxane B2 (TXB2) produced by stimulated blood cells was reduced in fish fed LO compared to those fed SFO. Prostaglandin E2 (PGE2) production was reduced in LO-fed fish compared to both other dietary treatments. Fish fed LO had reduced PC in heart membranes compared to the other two dietary treatments, resulting in a ratio of PC:PE (phosphatidylethanolamine) less than unity. Fish fed SFO developed a marked cardiac histopathology which, while present in FO-fed fish albeit in a less severe form, was virtually absent in fish fed LO. Fish fed SFO had increased heart phospholipase A activity compared to those given either FO or LO.

Animals↗
PubMed1993

Has percutaneous umbilical blood sampling improved the outcome of high-risk pregnancies?

PUBS offers distinct advantages to the perinatologist in the management of the high-risk pregnancy. Improvement in outcome has clearly been attained in the severely anemic fetus, for example, whereas fetal blood sampling has also led to great advances in both diagnosis and treatment of many other perinatal abnormalities. The exact role for PUBS in the management of problems such as intrauterine growth retardation and the fetus at risk for thrombocytopenia in ITP remains controversial. It is quite evident, however, that overall PUBS offers tremendous aid to the perinatologist in management of the high-risk pregnancy, with future promise for even greater application.

Blood Transfusion, Intrauterine↗
PubMed1993

Cordocentesis.

Access to the fetal circulation via cordocentesis has resulted in many advances in both prenatal diagnosis and fetal therapy over the past decade. In this review, current research in the assessment and treatment of erythrocyte isoimmunization and fetal infection by fetal blood sampling, as well as the role of cordocentesis in the evaluation of fetal platelet abnormalities, intrauterine growth retardation, fetal thyroid function, and genetic investigation, are discussed. Finally, a brief review of complications and loss rates relating to this procedure is given.

Chromosome Aberrations↗
PubMed1992

Effects of increasing dietary linoleic acid on phospholipid fatty acid composition and eicosanoid production in leucocytes and gill cells of Atlantic salmon (Salmo salar).

Diets containing linoleic acid at 10, 25 and 45% of total dietary fatty acids were fed to three groups of post-smolt Atlantic salmon (Salmo salar) for 18 weeks. Incorporation of linoleic acid into membrane phospholipids of leucocytes and gills increased in response to dietary intake. In general, there was an increase in arachidonic acid and a decrease in eicosapentaenoic acid in the individual phospholipids of both cell types in response to increasing dietary linoleic acid. These changes in eicosanoid precursors were reflected in significantly increased plasma concentrations of 6-keto-PGF1 alpha and TXB2 in salmon given the highest dietary linoleic acid. In whole blood stimulated with the calcium ionophore A23187, LTB4, 12-HETE and TXB2 were significantly increased and 12-HEPE significantly decreased in response to increasing dietary linoleic acid. In isolated gill cells stimulated with A23187, 12-HEPE, 12-HETE, 14-HDHE and TXB2 were all decreased in response to increasing dietary linoleic acid, although the ratio of 12-HEPE/12-HETE was also decreased.

6-Ketoprostaglandin F1 alpha↗
PubMed1992

The effect of improvement of umbilical artery absent end-diastolic velocity on perinatal outcome.

OBJECTIVES: The purpose of this study was to analyze cases in which antenatal improvement of absent fetal umbilical artery end-diastolic velocity was detected and to correlate improvement with perinatal outcome. STUDY DESIGN: Forty cases of umbilical artery absent end-diastolic velocity in singleton pregnancies were retrospectively reviewed. Maternal characteristics and perinatal outcomes were compared in cases where improvement of end-diastolic velocity was diagnosed and those in which no improvement was detected. RESULTS: Eleven cases of absent end-diastolic velocity showed antenatal improvement and were associated with more advanced gestational age at delivery, longer diagnosis-to-delivery interval, larger birth weights, and a lower incidence of neonatal death than those fetuses without antenatal improvement. CONCLUSION: Improvement of umbilical artery absent end-diastolic velocity can occur and is associated with improved pregnancy outcome when compared with patients without antenatal improvement of diastolic velocity.

Blood Flow Velocity↗
PubMed1992

Alterations in postnatal intestinal function during chronic hypoxemia.

Growth failure is a major complication of chronic hypoxemia, as seen in infants and children with cyanotic congenital heart disease. To determine whether chronic hypoxemia during infancy affects the gastrointestinal tract, we examined small intestinal growth and digestive enzyme activities in chronically hypoxemic newborn lambs and in age-matched controls. Chronic hypoxemia was produced by placing an inflatable occluder around the main pulmonary artery and performing a balloon atrial septostomy. Aortic oxygen saturation was reduced to 60-74% for 2 wk, after which the small intestine was removed for analysis. During chronic hypoxemia, somatic growth rate was decreased to 60% of control (hypoxemic, 135 +/- 20 versus control, 216 +/- 26 g/d, p less than 0.02). No differences in caloric intake were found (hypoxemic, 129 +/- 4 versus control, 128 +/- 4 kcal/kg/d). Chronic hypoxemia did not alter small intestinal growth, as measured by jejuno-ileal weight, jejuno-ileal length, mucosal weight, or mucosal protein or DNA contents. However, sp act of lactase, the principal disaccharidase of the infant lamb intestine, were significantly decreased (hypoxemic, 0.08 +/- 0.01 versus control, 0.146 +/- 0.03 units of enzyme activity/mg DNA, p less than 0.05), as were the total small intestinal contents of lactase (hypoxemic, 61.7 +/- 7.0 versus control, 120.6 +/- 21.7 units of enzyme activity, p less than 0.01). There also were decreases in specific and total activities of other digestive enzymes such as maltase, amino-oligopeptidase, and alkaline phosphatase in hypoxemic intestine that did not achieve statistical significance.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[Prevalence of Newcastle disease in traditional breeding facilities for chickens in Cameroon].

Although 65% of domesticated birds in the Cameroon are kept in traditional chicken farms, very little attention is given to this important sector by the administration as well as by the farmers themselves. This could be detrimental to the modern poultry sector where a lot of investments have been made during recent years. In order to estimate the danger of neglecting traditionally-raised chickens and the health threat they represent for the poultry population of the country, a study was conducted to evaluate the impact of Newcastle disease in traditional farms. A total of 180 chicken blood serum samples from three provinces of the Cameroon were submitted to the haemagglutination inhibition test; 51.66%, 48.33% and 46.66% of birds respectively from the East, West and North provinces reacted positively to the test. The consequences of such a situation are emphasised.

Animal Husbandry↗
PubMed1991

High dietary linoleic acid affects the fatty acid compositions of individual phospholipids from tissues of Atlantic salmon (Salmo salar): association with stress susceptibility and cardiac lesion.

For 16 wk Atlantic salmon (Salmo salar) post-smolts were fed practical-type diets that contained either fish oil (FO) or sunflower oil (SO) as the lipid component. Both diets contained adequate (n-3) polyunsaturated fatty acids (PUFA). All the phospholipids of heart and liver from SO-fed fish had increased levels of 18:2(n-6), 20:2(n-6) and 20:3(n-6); phosphatidyl choline (PC) and phosphatidyl ethanolamine (PE) also had increased 20:4(n-6). There was a general decrease in 20:5(n-3) in the phospholipids, reflected in an increase in the 20:4(n-6)/20:5(n-3) ratio, especially in PC and PE. The fatty acid compositions of phospholipids from brain and retina were much less affected by dietary linoleate than those of heart and liver. Fish fed SO developed severe heart lesions that caused thinning of the ventricular wall and muscle necrosis. The fish fed SO also were susceptible to a transportation-induced shock syndrome that caused 30% mortality. These results establish that a diet with a low (n-3)/(n-6) ratio can cause changes in fatty acid metabolism that are deleterious to the health of salmonid fish, especially when subjected to stress.

Animals↗
PubMed1991

Incorporation of [3H]arachidonic and [14C]eicosapentaenoic acids into glycerophospholipids and their metabolism via lipoxygenases in isolated brain cells from rainbow trout Oncorhynchus mykiss.

The incorporation of [3H]arachidonate [( 3H]AA) and [14C]eicosapentaenoate [( 14C]EPA) into glycerophospholipids was studied in isolated brain cells from rainbow trout, a teleost fish whose lipids are rich in (n-3) polyunsaturated fatty acids (PUFAs). EPA was incorporated into total lipid to a greater extent than AA, but the incorporation of both PUFAs into total glycerophospholipids was almost identical. The incorporation of both AA and EPA was greatest into phosphatidylethanolamine (PE). However, when expressed per milligram of individual phosphoglycerides, both AA and EPA were preferentially incorporated into phosphatidylinositol (PI), the preference being significantly greater with AA. On the same basis, significantly more EPA than AA was incorporated into phosphatidylcholine (PC). When double-labelled cells were challenged with calcium ionophore A23187, the 3H and 14C released from the cells closely paralleled each other, peaking at 10 min after addition of ionophore. The 12-monohydroxylated derivative was the pre-dominant lipoxygenase product from both AA and EPA with a rank order of 12-hydroxyeicosatetraenoic acid (12-HETE) greater than leukotriene B4 (LTB4) greater than 5-HETE greater than 15-HETE for the AA products and 12-hydroxyeicosapentaenoic acid (12-HEPE) greater than 5-HEPE greater than LTB5 greater than 15 HEPE for EPA products. The 3H/14C (dpm/dpm) ratios in the glycerophospholipids, total released radioactivity, and the lipoxygenase products suggested that PC rather than PI was the likely source of eicosanoid precursors in trout brain cells.

Animals↗
PubMed1990

Effect of marginal maternal zinc intake on zinc absorption and growth of 3-month-old infant rhesus monkeys.

One compensatory mechanism for marginal zinc intake may be through an enhanced absorption of zinc. Such a compensatory mechanism could be of value to the neonate, as poor zinc nutriture during early life has severe consequences on growth and development. We studied the uptake of zinc by 3-month-old infant rhesus monkeys born to dams fed control diets (100 micrograms of zinc per gram of diet or zinc-restricted diets (4 micrograms of zinc per gram of diet). Zinc uptake/retention was studied by feeding 3-month-old infant monkeys that had fasted an infant formula containing zinc 65 by gavage. Whole body radioactivity was counted immediately after intubation and on days 10 and 17 after intubation. Regardless of dietary group, 65 zinc retention was high, ranging from 33% to 71% of the dose fed to the monkeys. There were no significant differences between the two dietary groups in the percentage of zinc retention at days 10 and 17. Independent of the dietary group, there was no correlation between plasma zinc and zinc absorption. A positive correlation was found between weight gain and zinc retention in the marginal zinc infants, while a negative correlation between weight gain and zinc retention was observed in the control infants. These observations suggest that the mechanisms underlying growth may be different in infants born to dams fed control vs marginal zinc diets.

Animals↗
PubMed1990

Etiology of intestinal damage in gastroschisis, II. Timing and reversibility of histological changes, mucosal function, and contractility.

Previous work in the fetal lamb examined the relative effects of amniotic fluid and bowel constriction in the etiology of bowel damage in gastroschisis. The present study used the same model to assess the timing and reversibility of these changes during gestation. Gastroschisis was created at 80 days' gestation, and a tape was placed around the bowel to cause gradual constriction with growth. Lambs were killed at 100 days, 120 days, and term. Bowel damage was assessed using histology, mucosal enzyme activity, and in vitro motility. In an additional "repaired" group, the constrictor was removed at 120 days, a silastic pouch placed over the bowel, and bowel damage assessed at term. Normal fetuses at each gestational age were used as controls. A fibrous peel was observed at all gestational ages. Mucosal villous atrophy and mesenteric venous and lymphatic dilation were mild at 100 and 120 days, but severe at term. These changes were present but mild in repaired animals at term. Mucosal enzyme activity decreased gradually with gestational age; inhibition of maltase activity was maximal at term, and was significantly reversed by repair, whereas inhibition of aminooligopeptidase activity was maximal at 120 days, and was not affected by repair. Protein/DNA, DNA/weight, and protein/weight ratios showed that repaired mucosal cells were significantly more proliferative, smaller, and less mature than control or gastroschisis cells. In vitro motility studies demonstrated a mild decrease in contractility at 100 and 120 days, and a large decrease at term. This deleterious effect at the end of gestation was only partially reversed by repair in utero.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Muscles↗
PubMed1989

Higher retention of manganese in suckling than in adult rats is not due to maturational differences in manganese uptake by rat small intestine.

To test the hypothesis that the high absorption of manganese (Mn) in suckling rats compared to weanling rats is due in part to maturational differences in mucosal cell uptake of Mn, uptake kinetics of Mn were examined in isolated brush-border membrane vesicles prepared from the small intestine of rats at various ages (d 14, d 18, d 21). Initial uptake of Mn was rapid by vesicles from all age groups and reached an equilibrium plateau by 5 min in vesicles from suckling rats (d 14) and 10 min in vesicles from weanling rats (d 18, d 21). Uptake of Mn was associated with an osmotically active space. Uptake velocity was similar in all age groups and was nonsaturable at Mn concentration of 1-90 microM. The data were representative of a diffusional transport process. Mn uptake did not appear to be influenced by a putative ligand, L-histidine. However, incubations that included ascorbate did result in increased uptake of Mn by membrane vesicles. The results do not support the hypothesis that age-related differences in Mn retention in rats are due to maturational differences in the transport of Mn across small-intestinal brush-border membranes.

Age Factors↗