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Biomedical subjects

E Ryder

Publications and source records attributed to E Ryder.

At least 19 recordsLinked to original sources
PubMed1998

Lineage analysis using retroviral vectors.

Knowledge of the genealogical relationships of cells during development can allow one to gain insight into when and where developmental decisions are being made. Genealogical relationships can be revealed by a variety of methods, all of which involve marking a progenitor cell and/or a group of cells and then following the progeny. The use of replication-incompetent retroviral vectors for the analysis of lineal relationships in developing vertebrate tissues is described. An overview of the relevant aspects of the retroviral life cycle is given, and the strategies and current methods in use in our laboratory are described.

Animals↗
PubMed1997

Improved triglyceride control with low glycaemic index-high carbohydrate modified-lipid diet in a hypertriglyceridaemic child.

This study reports a 7-y-old boy with severe hypertriglyceridaemia who was successfully treated for 6 y with a low glycaemic index-high carbohydrate modified-lipid diet that produced beneficial changes in triglyceride and total cholesterol levels. It is suggested that a selection of a complex digestible carbohydrate and an adequate ratio between polyunsaturated and monounsaturated fat may, in the long term, favourably improve the lipid profile.

Child↗
PubMed1996

Isozyme analysis of human polymorphonuclear leukocyte phosphofructokinase from insulin resistant individuals.

Phosphofructokinase (PFK) from human polymorphonuclear leukocytes (PMN) was characterized by immunological titration with subunit specific antibodies and column chromatography on QAE-Sephadex in three different groups: control, type II diabetic, and obese individuals. It was found that PMN phosphofructokinase in the three groups consists mainly of a mixture of L4 and M4 homotetramers with possibly some hybrid forms. The predominant subunit was the L-type. A 24% decrease in the specific activity of the L-type isozyme was observed and an intermediate form (I-isozyme) having 23% of the total activity in diabetic individuals appeared. In obese individuals a 30% decrease was observed in the activity of M-type isozyme and 9% of the total activity corresponded to the intermediate form. Kinetic studies showed different regulatory properties among the isozymes from the three groups. The lower PFK activity found in diabetic and obese individuals can be associated with the decreased activity in the L-type isozyme (for diabetic individuals) and in the M-type isozyme (for obese individuals); the lower activity can also be associated with the four times lower affinity for F-6-P showed by the M-type isozyme, the decreased sensitivity to ATP inhibition (for both isozymes), and the appearance of an intermediate form with a different kinetic behaviour.

Adenosine Triphosphate↗
PubMed1996

[Qualitative and quantitiative differences in the plasma lipoproteins of obese, hyperlipidemic or normolipidemic men and women].

The aim of this study was to evaluate the alterations of the lipoprotein composition and their relation with the insulin-resistance and/or hyperinsulinemia in non diabetic obese patients. Twenty-two no obese(13 women and 9 men) and 30 obese patients (BMI > 30) were studied, who were divided into two groups according to the total lipid levels. The first group was formed by 18 obese patients (10 women and 8 men) with normal serum cholesterol (Chol) concentration < 200 mg/dL and triglycerides (TG) < 150mg/dL (NO), while the second group were formed by 12 obese patients (3 women and 9 men) with elevated Chol level > 200mg/dL and/or TG > 150 mg/dL (HO). A clinical and anthropometric examination was performed to each patient, as well as a glucose tolerance test, including serum glucose and insulin determinations. Likewise, the plasma lipoproteins (VLDL, LDL, HDL2 and HDL3) were isolated by ultracentrifugation and their cholesterol and triglycerides content were determined by enzymatic methods. In this report, we demonstrate the existence of compensatory basal hyperinsulinemia in men and women on both obese patients populations as well as alterations in the lipoprotein composition, mostly a TG overload even on NO. On the other hand, the presence of lipids and lipoproteins modification were obvious in those patients with abdominal obesity, on whom the hyperinsulinemia was more evident, which could be related with the high risk of cardiovascular disease in this kind of patients.

Adult↗
PubMed1995

Isozyme analysis of human normal polymorphonuclear leukocyte phosphofructokinase.

Phosphofructokinase (PFK) from human polymorphonuclear leukocytes (PMN) was characterized by immunological titration with subunit specific antibodies, column chromatography on QAE-Sephadex and SDS-polyacrylamide gel electrophoresis. Two different isozymes, M-type and L-type, were found. The M(r) values of the M and L subunits were 79,500 +/- 1,914 and 74,250 +/- 1,258, respectively. The two isozymes presented different kinetic and regulatory properties. The results suggest that PFK from human normal PMN is a mixture of M-type and L-type homotetramers, mainly, with possible minor heterotetrameric forms.

Adenosine Triphosphate↗
PubMed1995

[Role of environmental factors in the development of insulin-dependent diabetes mellitus (IDDM) in Venezuelan children].

In view of the controversy surrounding the role of environmental factors, such as the presence of bovine albumin in milk, or viral infections, in the etiology of IDDM, a study was undertaken to determine the relationship between these events and the subsequent risk of developing IDDM. On 40 venezuelan diabetic children (< 18 y) and forty, age, sex and race-matched controls were studied at the same time. Parents of children completed a questionnaire on the infant's feeding habits, its environment and family history. The X2 method and the Fischer's exact test were used to analyze the results. We found that 20% of the controls, and 10% of IDDM (NS), were never breast-fed. In 95% of controls vs 65% of IDDM (p < 0.001), cow's milk was given exclusively from birth, or combined with breast-feeding, 65% of IDDM and 60% of controls (NS) were breast-fed (alone or combined with milk substitutes) for more than three months. These results do not support the hypothesis that early exposure to breast milk substitutes increases the risk of IDDM in venezuelan children. The study revealed, however, that a family history of diabetes mellitus was present in 55% of IDDM vs 30% of controls (p < 0.05) and mumps infection before the onset of diabetes was recorded in 42.5% of IDDM in comparison with 12.5% of controls (p = 0.005). Other viral infections (rubella, chicken pox) had no statistical significance. The latter results suggest an association between a family history of diabetes mellitus and viral infections with the development of IDDM among this group of children.

Adolescent↗
PubMed1995

[Dyslipidemia and hyperinsulinemia in normoglycemic-obese relatives of patients with non-insulin dependent diabetes mellitus].

To determine the most frequent dyslipidemias among first-degree relatives of NIDDM patients, and its association with their glucose-tolerance status and hyperinsulinemia, we have started to examine members of NIDDM pedigrees, according to American Diabetes Association guidelines for nuclear family studies. In a large family with 2 NIDDM siblings in the 2nd generation, and 4 siblings with NIDDM in the 3rd generation, we have evaluated 14 first degree relatives and also 15 sex and aged matched healthy control subjects without family history of diabetes. The NIDDM relative group presented BMI = 31.8 +/- 3.9 kg/m2, SBP = 128 +/- 18.2 mmHg, DBP = 84 +/- 12.7 mmHg. Both relatives and controls were subjected to a 2h 75g OGTT for glucose and insulin determinations. Although none of NIDDM relatives has IGT, both Glycemic Area (GA) and Insulin Area (IA) were greater (p < 0.01) in the NIDDM relative group. The Insulin/Glucose ratio was also higher (p < 0.01) at 0 and 120 min of OGTT, this might be indirect evidence of Insulin- Resistance. Fasting serum lipids in the NIDDM relatives were TG = 148 +/- 24mg/dl, T-Chol = 244 +/- 10.7mg/dl, HDL-C = 34.2 +/- 2.5mg/dl; lipids in the control group were TG = 84.8 +/- 10.1mg/dl, T-Chol = 167 +/- 10.2mg/dl, HDL-C = 44.4 +/- 2.6mg/dl. Electrophoretic pattern showed type IIa (30.7%) and IIb (61.5%) hyperlipidemias in the NIDDM relatives. In this group, there was a positive and significant association between basal insulin and DBP (r = 0.67; p < 0.01), and between DBP and both TG (r = 0.74; p < 0.01)) and VLDL-C (r = 0.58; p < 0.05). It was also obtained a negative association between basal insulin and HDL-C (r = -0.89; p < 0.001). These data suggest that hyperinsulinemia in association with lipid abnormalities could appear early (before the development of Impaired Glucose Tolerance and Diabetes) in first degree relatives of NIDDM patients.

Adult↗
PubMed1994

Insulin and lipogenesis in rat adipocytes. II. Effect of high levels of insulin and glucose on lipid synthesis in isolated rat adipocytes.

Insulin resistant states are characterized by receptor and post-receptor defects in insulin action. When the insulin resistant state progresses, elevated levels of insulin are accompanied by increasing levels of glucose. In a previous paper we demonstrated that treatment of isolated adipocytes with high levels of insulin led to a decrease in insulin binding as well as a decrease in basal and insulin-stimulated lipid synthesis. The results of the present study establish that the addition of high concentrations of glucose in combination with a high level of insulin, does not modify the decrease in binding of insulin to its receptor. However, the decrease in lipid synthesis previously observed in the presence of high concentrations of insulin was completely overcome by the presence of high glucose.

Adipocytes↗
PubMed1994

Gerontology within district nurse education.

This paper describes a research study designed to explore approaches to integrating gerontological principles within district nurse education courses. Data were collected by a descriptive survey approach. The findings of the study indicated that various approaches were used to incorporate gerontological content within the curriculum. The district nurse lecturer emerged as the crucial link in ensuring subject material related to the specialism of district nursing, and the community practice teacher was significant in enabling students to relate gerontological theory to practice-based learning. The district nurse lecturer also emerged as supportive of the multi-disciplinary nature of gerontology by encouraging shared learning activities with a range of other community health care students. Against the background of major changes in community health care delivery, district nurses are identifying areas of expertise within their role as community health care nurses. One such area of expertise lies in the care of older people within the community, who form a high percentage of patients on the district nurse's caseload. In order to ensure that district nurses are effectively prepared to meet the specialist needs of older people, district nurse education courses must incorporate gerontological content within their programmes.

Aged↗
PubMed1994

[Glycemic index and insulin response to the ingestion of precooked corn flour in the form of "arepa" in healthy individuals].

With the purpose of exploring the glucose and insulin responses to a breakfast composed of a complex carbohydrate (CC) in the form of a "arepa" prepared with precooked corn flour, with or without the addition of protein and fat (CC + P + F), we studied 6 healthy volunteers, ages ranging from 26-50 years and body mass index of 24.5 +/- 1.32. Three tests were performed on each individual: 1) 75 g OGTT, 2) Ingestion of 75 g of CC ("arepa") and 3) Ingestion of 75 g of CC + 6.7 g protein (low fat cheese) and 4 g fat (margarine). Glycemic values (glucose - oxidase method) and insulinemia (radioimmunoassay) were determined at basal, 30, 60, 120, 180 and 240 min. Glucose (GA) and insulin (IA) areas, glycemic index (GI) and insulin/glucose ratio (I/G) were calculated. We found that the "arepa" has a high GI (71.5%) that it is increased, although not significatively to 140% with the addition of protein and fat. Total GA as well as IA obtained for CC and for CC + P + F were similar to OGTT, however the profiles of the glucose and insulin responses during CC and CC + P + F were less abrupt but more prolonged, resulting in a greater I/G ratio for OGTT in comparison with CC or CC + P + F during the initial steps. We conclude that GI of this corn bread ("arepa") is high in comparison to other complex carbohydrates and it is not altered by the addition of protein and fat. This is possibly due to glucose and insulin responses similar to that produced by OGTT.

Adult↗
PubMed1993

[Hyperinsulinism and lipid changes in the early stages of essential arterial hypertension].

The purpose of this study was to evaluate the presence of insulin-resistance in non-obese, non-diabetic patients with mild to moderate essential arterial hypertension of recent diagnosis and without prior pharmacological treatment and its relationship with the lipid alteration found in those patients. Twenty-one controls (9 M/12F) and twenty-nine patients (19 M/10 F) were studied. The control group presented mean age: 29 +/- 1.5 years, BMI: 23.9 +/- 0.46 Kg/m2, SBP: 112.6 +/- 2.9 mm Hg, DBP: 68.0 +/- 2.9 mm Hg. The patient group presented mean age: 35 +/- 1.4 years, BMI: 27.3 +/- 0.45 Kg/m2, SBP: 140 +/- 26 mm Hg, DBP: 95.1 +/- 1.4 mm Hg. The fasting levels of glucose, insulin and lipids were measured in each individual. Both controls and patients were subjected to an oral glucose tolerance test (OGTT) with determination of glucose and insulin at 30, 60, and 120 minutes. The patients had significantly (p < 0.05) increased plasma glucose at 0, 30, 60 and 120 min. and increased (p < 0.05) plasma insulin levels at O and 120 min compared to controls. The G/I ratio was significantly lower (p < 0.005) in the hypertensive group, at 0 h and 120 min. Abnormalities in fasting lipid profile were also observed in the patients including a significant increase in TG, Cholesterol, VLDL-C and LDL-C. These increases were especially evident in men and those with higher BMI. There was a positive and significant association between basal-insulin and TG, VLDL-C and DBP in hypertensive patients. We conclude that hyperinsulinemia is present in the majority of hypertensive patients and that hyperinsulinemia is associated with lipid abnormalities specially in men and the most individuals with higher BMI.

Adult↗
PubMed1993

[Effect of low doses of estrogens in menopausal women].

The effect of hormonal therapy in serum glucose, lipoproteins and the hemostatic system was studied in menopausal women, who were distributed in three groups: Group I (15 patients) received placebo in cycles of 21 days, followed by 7 days of rest; Group II (16 patients), received natural estrogens conjugated with progesterone in a sequential way, also in cycles of 21 days: Group III (16 patients), was treated with triphasic oral contraceptives in the same cyclical fashion. The patients completed 6, 12 or 18 cycles of the treatment. The results were as follows: The glucose levels were decreased by the 18th cycle in group II (P < 0.01). The HDL-cholesterol levels and the cholesterol/HDL cholesterol index were unchanged, however the basal levels of LDL-cholesterol in group III were high, but normal after 12 cycles of treatment. The coagulation factors did not changed significantly with the hormonal treatment, however fibrinogen was increased after 18 cycles under placebo. The von Willebrand factor and antithrombin III remained stable. Platelet aggregation with ADP increased after 12 cycles in group III (p < 0.05), and no changes were found with collagen. The above results suggest that the hormonal treatment in menopausal women, either with natural estrogens and progesterone or with triphasic oral contraceptives, has little effect in the lipidic concentrations of sera in these patients, however it can increase platelet activity, specially with prolonged treatment with semisynthetic estrogens.

Blood Coagulation Factors↗
PubMed1992

Insulin and lipogenesis in rat adipocytes. I. Effect of insulin incubation on lipid synthesis by isolated rat adipocytes.

To assess the effect of insulin on lipid synthesis in isolated rat adipocytes, cells were preincubated for 3 h with high concentrations (16.6 nM) of the hormone and lipogenesis measured through 14C-acetate incorporation into lipids, analyzing at the same time the activity of some lipogenic enzymes. It was found that insulin induced not only a decrease in the number of insulin receptors but a 30% loss in basal and insulin-stimulated acetate incorporation into total lipids as well as a decrease in the activities of enzymes related to the novo fatty acid synthesis pathway as malic enzyme and glucose-6-phosphate dehydrogenase.

Acetates↗