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Biomedical subjects

F Bennett

Publications and source records attributed to F Bennett.

At least 37 records · Page 2Linked to original sources

Kidney function in phasic insulin dependent diabetes mellitus in Jamaica.

In Jamaica, malnutrition related diabetes mellitus (MRDM) presents the clinical picture of phasic insulin dependence. This study was undertaken to investigate nephropathic changes associated with this group of patients. Fourteen phasic insulin dependent diabetes mellitus (PIDDM) patients were compared with 10 insulin dependent (IDDM) and 10 non-insulin dependent (NIDDM) diabetes mellitus patients, and 10 normal controls. Each group was matched for age, sex, body mass index (BMI) and, in the case of the diabetic patient controls, duration of diabetes. Urinary microalbumin concentration was significantly (p < 0.05) higher in the PIDDM group (mean +/- SD: 153 +/- 48.3 mg/dl) than in the groups of NIDDM (35.7 +/- 9.6 mg/dl) or IDDM (38.6 +/- 15.8 mg/dl) patients. Serum urea and creatinine concentrations (mean +/- SE 7.6 +/- 1.0 mmol/l and 130.0 +/- 20.3 mumol/l, respectively) were higher in the PIDDM patients than in the NIDDM and IDDM groups. Confounding factors such as hypertension and urinary tract infections were excluded as causes for these differences. We conclude that PIDDM patients have more severe renal dysfunction than NIDDM patients and, since glycosylated haemoglobin concentrations are comparable in these groups, we attribute this to a renal insult due to malnutrition predating the onset of the PIDDM.

Albuminuria↗

Obesity in the Caribbean.

People of African origin who live in the Caribbean share a common genetic heritage but live in socioeconomic environments that diverge widely. A cross-cultural study of males and females from Jamaica, St. Lucia and Barbados investigated the prevalence of hypertension and its environmental determinants. Standardized measurement techniques allowed comparable measurements of weight, height, waist and hip circumferences, and blood pressure. The population values for body mass index (BMI), per cent overweight (males BMI > or = 27.8 kg/m2; females BMI > or = 27.3 kg/m2) and per cent obese (males BMI > or = 31.1 kg/m2; females BMI > or = 32.3 kg/m2) are presented. Prevalence of hypertension is based on the age-adjusted total population. The gradient in per capita gross national product in Jamaica, St. Lucia and Barbados parallels the gradient in the proportions of population in those countries who are obese. BMI explained 26% of the variance in blood pressure in females and 13% in males. Obesity is a significant problem in the Caribbean, as it is in many other developing countries, and it is associated with a high prevalence of hypertension, particularly in women.

Body Composition↗

Obesity in peoples of the African diaspora.

People of African descent in the Caribbean and the USA originated from the Bight of Benin in West Africa. Although these populations share a common genetic heritage, they now live under different socioeconomical conditions. Assuming genetic similarity, a cross-cultural examination of these peoples in West Africa, the Caribbean and the USA may attenuate the effect of genetic factors and allow the assessment of environmental contributions to a biological outcome. We carried out an epidemiological survey to determine the prevalence of hypertension and the contribution of risk factors to the variation in blood pressure. We measured the height, weight, waist and hip circumferences, and blood pressure of adults in Nigeria, Cameroon, Jamaica, St. Lucia, Barbados and the USA. In urban populations there was a trend towards increasing weight, height, body mass index, and proportions of those overweight and obese going from West Africa to the USA, with the Caribbean being intermediate. The prevalence of hypertension lay on a similar gradient. Given a common genetic susceptibility, urbanization and western acculturation are therefore associated with increasing hypertension and obesity.

Adult↗

Development of food frequency questionnaires in three population samples of African origin from Cameroon, Jamaica and Caribbean migrants to the UK.

OBJECTIVES: To develop the methods for assessment of food and nutrient intake using standardized food frequency questionnaires (FFQ) in three African origin populations from Cameroon, Jamaica and Caribbean migrants to the United Kingdom. DESIGN: Cross-sectional assessment of diet from a representative sample in each site, using either a 2-day food diary or a 24-h recall method to determine foods for inclusion on the food frequency questionnaire. SETTING: A rural and urban site in Cameroon, Evodoula and Cite Verte in Yaounde, respectively; a district in Kingston Jamaica; African-Caribbeans living in central Manchester, UK. SUBJECTS: Aged 25-79 years, 61 from the Cameroonian urban site, 62 from the village site; 102 subjects from Jamaica (additional analysis on a subsample of 20): 29 subjects from Manchester, UK. MAIN OUTCOME MEASURES: Foods contributing to nutrients in each site to allow the development of a FFQ. RESULTS: A high response rate was obtained in each site. Comparison of macronutrient intakes between the sites showed that carbohydrate was the most important contributor to energy intake in Jamaica (55%) and the least in rural Cameroon. In rural Cameroon, fat (mainly palm oil) was the most important contributor to energy intake (44%). Manchester had the highest contribution of protein to energy (17%). Foods contributing to total energy, protein, fat and carbohydrate were determined. In rural Cameroon, the top 10 food items contributed 66% of the total energy intake compared to 37% for the top 10 foods in Manchester. Foods contributing to energy were similar in Jamaica and Manchester. Cassava contributed 44% of the carbohydrate intake in rural Cameroon and only 6% in urban Cameroon. One FFQ has been developed for use in both sites in Cameroon containing 76 food items. The FFQ for Jamaica contains 69 foods and for Manchester 108 food items. CONCLUSION: Considerable variations exist within sites (Cameroon) and between sites in foods which are important contributors to nutrient intakes. With careful exploration of eating habits it has been possible to develop standardized, but locally appropriate FFQs for use in African populations in different countries.

Adult↗

Molecular cloning and characterization of murine interleukin-11.

Human interleukin-11 (IL-11) has been shown to have pleiotropic action on hematopoietic, hepatic, stromal, epithelial, neural, and osteoclast cells. In the present work, the murine IL-11 cDNA has been isolated from a fetal thymic cell line, and its structure and function compared with human IL-11. The murine protein was demonstrated to have identical actions on the proliferation of a murine plasmacytoma cell line, murine primitive bone marrow progenitor cells, and megakaryocyte precursors. The murine IL-11 protein was synthesized as a soluble thioredoxin-IL-11 fusion in Escherichia coli and the expression of murine IL-11 was examined by pulse-chase radiolabeling in COS cells. The chromosomal location of the murine IL-11 gene was assigned to the proximal arm of chromosome 7.

Amino Acid Sequence↗

Alanine-scanning mutagenesis of human interleukin-11: identification of regions important for biological activity.

We have identified functionally important regions of human interleukin-11 (hIL-11) by means of alanine-scanning mutagenesis. A total of 61 mutated forms of hIL-11 were produced in E. coli as thioredoxin fusion proteins and tested in a murine T10 plasmacytoma proliferation assay. Mutations made at several positions proximal to the hIL-11 C-terminus caused substantial reduction in biological activity. In addition a number of other mutations in this region affected either protein folding or stability. Both effects displayed a characteristic periodicity with respect to the primary sequence which suggested that residues close to the C-terminus of hIL-11 adopt a helical conformation. Mutations made proximal to the N-terminus of hIL-11 also exhibited reduced bioactivity, although no effects on protein folding or stability were observed. The N-terminal mutations with reduced activity also mapped with a periodicity suggestive of a helical conformation. We previously have proposed a four-helix bundle topology for the hIL-11 structure based on physical studies, selective chemical modifications, positions of intron/exon boundaries, limit proteolysis experiments and site-directed mutagenesis. The alanine-scanning mutagenesis data we report here provide additional support for this model.

Alanine↗

The synthesis of novel HIV-protease inhibitors.

The syntheses, enzyme inhibition and antiviral activity of potent HIV-protease inhibitors containing novel beta-hydroxy ether and thioethers based on the transition state mimetic concept are discussed.

Amino Acid Sequence↗

Helicobacter pylori in patients undergoing upper endoscopy in Jamaica.

One hundred and two consecutive patients undergoing upper gastrointestinal endoscopy were tested for H. pylori by a rapid urease test, using antral biopsy specimens. There were 60 men (mean age 54 yrs) and 42 women (mean age 49 yrs). Fifty-six patients (55%) were positive for H. pylori. Of male patients, 36 (60%) and of female patients, 20 (48%) tested positive. Sixty-eight per cent of patients with antral gastritis, 65% with duodenal ulcer and 60% with gastric ulcer had H. pylori. Thirty-nine patients (70%) positive for H. pylori were from major urban areas, and 17 (30%) were from rural areas of Jamaica. In patients without H. pylori, 61% and 39% were from urban and rural areas, respectively. Forty-four patients (79%) with H. pylori and 40 (87%) without H. pylori had piped water in their homes. Ninety-three per cent of all patients had electricity and 88% had refrigeration. There was no difference between patients positive or negative for H. pylori with regard to the use of alcohol, marijuana or tobacco. There was also no difference between both groups in exposure to domestic animals in the home environment. H. pylori is associated with antral gastritis and peptic ulcer disease in Jamaican patients. There are no specific environmental or social factors that seem to predispose to infection.

Duodenitis↗

Lack of a role of interleukin 11 in the growth of multiple myeloma.

Interleukin (IL) 11 is a recently described lymphokine which, like IL-6, stimulates normal hematopoietic murine and human hematopoietic progenitor cells and therefore has potential value for either enhancing hematopoiesis in disease states or augmenting hematopoietic recovery after myeloablative therapies. Since IL-6 is known to promote the growth of human myeloma, either in an autocrine or paracrine fashion, we examined the effect of IL-11 on the growth of a murine plasmacytoma cell line, human myeloma-derived cell lines, and freshly isolated human myeloma cells. Interleukin 11 does increase DNA synthesis by the murine plasmacytoma line T10 in the presence of neutralizing antibody to IL-6. However, neither human myeloma cells nor derived cell lines express IL-11 mRNA; secrete IL-11; express IL-11 cell surface receptors; or augment either DNA synthesis or Ig secretion in response to exogenous IL-11. These findings strongly suggest that IL-11 does support the growth of a murine plasmacytoma cell line but does not play a role in the growth of either freshly isolated human myeloma cells or derived cell lines.

Animals↗

Child benefit. The reasons why.

Should universal child benefit be replaced with a child tax allowances? Or 'targeted' on poor families? Child Poverty Action Group director, Fran Bennett, examines the arguments and concludes that child benefit both deserves and needs defending.

Child↗

Molecular cloning of a cDNA encoding interleukin 11, a stromal cell-derived lymphopoietic and hematopoietic cytokine.

Hematopoiesis occurs in close association with a complex network of cells loosely termed the hematopoietic microenvironment. Analysis of the mechanisms of microenvironmental regulation of hematopoiesis has been hindered by the complexity of the microenvironment as well as the heterogeneity of hematopoietic stem cells and early progenitor cells. We have established immortalized primate bone marrow-derived stromal cell lines to facilitate analysis of the interactions of hematopoietic cells with the microenvironment in a large animal species. One such line, PU-34, was found to produce a variety of growth factors, including an activity that stimulates the proliferation of an interleukin 6-dependent murine plasmacytoma cell line. A cDNA encoding the plasmacytoma stimulatory activity was isolated through functional expression cloning in mammalian cells. The nucleotide sequence contained a single long reading frame of 597 nucleotides encoding a predicted 199-amino acid polypeptide. The amino acid sequence of this cytokine, designated interleukin 11 (IL-11), did not display significant similarity with any other sequence in the GenBank data base. Preliminary biological characterization indicates that in addition to stimulating plasmacytoma proliferation, IL-11 stimulates the T-cell-dependent development of immunoglobulin-producing B cells and synergizes with IL-3 in supporting murine megakaryocyte colony formation. These properties implicate IL-11 as an additional multifunctional regulator in the hematopoietic microenvironment.

Amino Acid Sequence↗

Persistence of high leucocyte sodium and blood pressure after pre-eclampsia.

Blood pressure and leucocyte sodium content were measured in black Jamaican patients with pre-eclampsia and pregnant controls. Similar measurements were made in a group of mothers who had pre-eclampsia 36-38 weeks previously and their controls. An increase in cell sodium accompanied the high blood pressure in patients with pre-eclampsia. There was also some elevation of both blood pressure and cell sodium in patients who had had pre-eclampsia 36-38 weeks previously. These findings suggest that disturbances of cellular electrolytes continue into the post-partum period. Changes in intracellular sodium may be important in the pathogenesis of pre-eclampsia as they parallel the increase in blood pressure levels.

Adolescent↗

Estradiol binding to plasma proteins after changing to a low-fat diet.

Breast cancer development is believed to be associated with both dietary fat consumption and the proportion of biologically available estradiol in the serum. A study was undertaken to determine if a reduction in fat consumption would influence the binding, and thus the bioavailability, of estradiol. Groups of pre- and postmenopausal women were randomized to begin either a standard western diet (40% energy from fat) or a low-fat diet (20% energy from fat). After two months, each woman changed over to the alternate diet. Blood samples were taken at the end of each dietary period. Change of diet made no significant difference to the proportions of nonprotein-bound (free), albumin-bound, or sex hormone binding globulin-bound estradiol in this study. However, the number of women studied and the duration of change were relatively small.

Adult↗

Profile of a meeting: how abstracts are written and reviewed.

We analyzed submissions to a recent scientific program to determine (1) how abstracts were reviewed and (2) what constituted a successful abstract. We found that (1) reviewers' gradings varied from 2-29%, in some instances differing significantly; (2) many (<74%) abstracts had inadequacies in form, title, introduction, aims, methods, results, and conclusions(collectively termed "content") or lacked numerical or statistical data; (3) accepted abstracts had fewer inadequacies and better "content"; and (4) abstract grades correlated closely with "content". The quality of preparation and of individual features of abstracts led to favorable review. This information is of potential value to scientists preparing and reviewing abstracts and planning programs.

Abstracting and Indexing↗

Leukaemia inhibitory factor is identical to the myeloid growth factor human interleukin for DA cells.

Leukaemia inhibitory factor (LIF) is a cytokine that induces macrophage differentiation of the murine M1 myeloid leukaemia cell line. We have isolated a cDNA clone encoding a novel human haemopoietic growth factor, human interleukin for DA cells (HILDA) that supports the proliferation of the murine interleukin-3-dependent leukaemic cell line, DA-la (refs 3-5). HILDA proved to be identical to LIF. The demonstration that the differentiation factor LIF will also serve as a growth factor for at least one myeloid leukaemic cell line provides further evidence that the distinction between growth-promoting and differentiation-inducing activities are largely determined by the target cell type.

Animals↗

The implementation of postgraduate training programs through state and local resources.

A profile of implementation strategies for funding postgraduate training programs using local or state resources is described. The need for those implementation strategies as well as basic principles for successful implementation is documented. Two programs are briefly described--a University Affiliated Program (UAP) in western New York and a UAP in Missouri--as the basis for generating implementation strategies. Finally a discussion is provided reviewing the strengths and weaknesses of these strategies.

Developmental Disabilities↗