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Biomedical subjects

J G Bell

Publications and source records attributed to J G Bell.

At least 19 recordsLinked to original sources
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↗
PubMed1988

Antibiotic resistance of Escherichia coli strains isolated from chickens with colisepticaemia in Morocco.

Sixty-two strains of Escherichia coli were isolated in 58 farms from broiler chickens showing respiratory signs and lesions characteristic of avian colibacillosis. Serological examination of these strains showed that the types 078, 01 and 02 (for the somatic antigen) and K1 (for the capsular antigen) were the most frequently found. Newcastle disease virus was also isolated in two cases. All the strains of E. coli isolated were sensitive to colistin, flumequine and gentamicin. A few strains were resistant to neomycin, nalidixic acid and trimethoprim. The frequency of strains resistant to nitrofurans, sulfonamides, chloramphenicol, spectinomycin and ampicillin was intermediate. Most strains were resistant to tetracycline. Multiple resistance was common.

Animals↗
PubMed1988

Radioimmunoguided surgery using monoclonal antibody.

The potential proficiency of radioimmunoguided surgery in the intraoperative detection of tumors was assessed using labeled monoclonal antibody B72.3 in 66 patients with tissue-proved tumor. Monoclonal antibody B72.3 was injected 5 to 42 days preoperatively, and the hand-held gamma-detecting probe was used intraoperatively to detect the presence of tumor. Intraoperative probe counts of less than 20 every 2 seconds, or tumor-to-adjacent normal tissue ratios less than 2:1 were considered negative (system failure). Positive probe counts were detected in 5 of 6 patients with primary colon cancer (83 percent), in 31 of 39 patients with recurrent colon cancer (79 percent), in 4 of 5 patients with gastric cancer (80 percent), in 3 of 8 patients with breast cancer (37.5 percent), and in 4 of 8 patients with ovarian cancer (50 percent) undergoing second-look procedures. Additional patients in each group were scored as borderline positive. Overall, radioimmunoguided surgery using B72.3 identified tumors in 47 patients (71.2 percent), bordered on positive in 6 patients (9.1 percent), and failed to identify tumor in 13 patients (19.7 percent). Improved selection of patients for antigen-positive tumors, the use of higher affinity second-generation antibodies, alternate routes of antibody administration, alternate radionuclides, and more sophisticatedly bioengineered antibodies and antibody combinations should all lead to improvements in radioimmunoguided surgery.

Antibodies, Monoclonal↗
PubMed1988

Effect of phytate removal on zinc absorption from soy formula.

Low zinc bioavailability from soy formula may be the result of the formula's phytate content. We assessed the effect of phytate removal from soy formula on Zn absorption using infant rhesus monkeys and suckling rat pups as animal models. Zn absorption in monkeys, as determined by whole-body counting, was 65% from human milk, 54% from monkey milk, 60% from whey-predominant formula, 46% from casein-predominant formula, and only 27% from conventional soy formula (0.621 mmol phytate/L). In contrast, Zn absorption from dephytinized soy formula (0.067 mmol phytate/L) was 45%. In suckling rats, Zn absorption from conventional soy formula was only 16% vs 47% from dephytinized soy formula. Phytate concentration in a variety of experimental soy formulas was inversely correlated to Zn absorption. These results suggest that the low bioavailability of Zn from soy formula is a function of its phytate concentration and can be overcome by the removal of phytate.

Animals↗
PubMed1988

Wrist pain.

Acute and chronic wrist pain are problems frequently seen by primary care physicians. The impact of wrist pain on function is substantial and requires prompt attention and treatment by physicians. In this article we summarize the causes of wrist problems, provide an approach to wrist pain, and discuss some of the common disorders seen by primary physicians.

Diagnosis, Differential↗
PubMed1987

Studies on the putative role of gamma-glutamyl transpeptidase in intestinal transport of amino acids in Atlantic salmon.

The gamma-glutamyl cycle is considered to function in the membrane transport of amino acids, particularly glutamine and cysteine. When groups of Atlantic salmon were fed either a control diet containing 45% crude protein or an amino acid diet (of similar overall amino acid composition but containing elevated levels of glutamine and cysteine) for 16 weeks, weight gains were significantly greater in the former group than in those given the amino acid diet. There were no significant differences between treatments in gamma-glutamyl transpeptidase (GT) activity in the proximal intestine; in distal intestine there was significantly more activity in control fish. Mean levels of GSH were higher in tissues (pyloric caeca, distal intestine and kidney) of amino acid diet fish than in those of control fish. Glutamine was less effective as a gamma-glutamyl acceptor than several other amino acids when tested with salmon caecal GT. There were no morphological adaptations to the two feeds. Nutrient uptake studies showed an increased uptake of glutamine, but decreased uptakes of proline and methionine in proximal intestine of salmon fed amino acid diet. Much the greater part of the glutamine uptake, even at high concentrations was shown to be by Na+ dependent processes. There is no evidence that GT itself is Na+ dependent. The results do not support the view that the gamma-glutamyl cycle and GT in particular are involved in the transport of amino acids in the intestine and are discussed in this context.

Amino Acids↗
PubMed1987

Vaccination against Moroccan strains of Newcastle disease virus.

Different vaccination programmes commonly used in Moroccan poultry farms were tested for their capacity to protect chickens against two representative Moroccan strains of velogenic viscerotropic Newcastle disease virus under controlled conditions. All vaccination programmes protected the chickens against mortality and the inactivated vaccine gave the highest antibody titres and the best protection against respiratory symptoms.

Animals↗
PubMed1977

An elementary study of deformation of molar teeth during amalgam restorative procedures.

A technique using an optical comparator was employed to examine the dimensional changes resulting from cavity preparation, application of the matrix and packing with amalgam in three extracted molar teeth. The changes have been reported and the nature of the change discussed. A modification in the use of the matrix and amalgam packing technique is suggested.

Dental Amalgam↗