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Biomedical subjects

M Hartog

Publications and source records attributed to M Hartog.

At least 91 records · Page 5Linked to original sources
PubMed1977

The measurement of serum free insulin by steady-state gel filtration.

A method for the separation of bound and free insulin in the serum of insulin treated diabetics by steady state gel filtration is described. The method meets the criteria which have been suggested for the validation of a method of separating bound from free ligand. The precision of the method is satisfactory, and the results compare well with those obtained by the methods of ethanol precipitation and polyethylene glycol precipitation.

Chromatography, Gel↗
PubMed1977

Serum free insulin concentrations during the treatment of diabetic coma and precoma with low dose intramuscular insulin.

Fifty patients in diabetic coma or precoma, 33 of whom had previously received insulin and had circulating insulin antibodies, were studied during treatment with a low-dose intramuscular insulin regime. In the presence of insulin antibodies, serum free insulin was separated from bound insulin by steady-state gel filtration. The initial mean serum free insulin concentration in the group of patients without insulin antibodies was 9 mU/1, 1 to 2 hours after intramuscular therapy it had risen to 22 mU/1, and after 7 to 8 hours to 73 mU/1. The corresponding concentrations for the group with insulin antibodies were 13, 23 and 74 mU/1. No relationship was found between the concentrations of serum free insulin attained and the age of the patients, their initial degree of acidosis, dehydration, and systolic blood pressure, the insulin antibody characteristics of their sera, nor the rate of decline of the blood glucose.

Adolescent↗
PubMed1977

The urinary sodium: potassium ratio and response to diuretics in resistant oedema.

Nineteen patients with severe oedema due to either cirrhosis of the liver or to congestive cardiac failure, who had failed to respond to previous diuretic therapy, were treated with either increasing doses of frusemide (Group A), or with frusemide in a fixed dose of 80 mg daily and increasing doses of spironolactone (Group B). In Group A there was an inverse correlation between the baseline 24-hr urinary sodium: potassium (Na : K) ratio and the 24-hr urinary potassium excretion during diuresis, and a direct correlation between the urinary Na : K ratio before and after diuresis. Thus, in patients of this group during diuresis, there was a significantly higher urinary potassium excretion in those with a baseline urinary Na : K ratio of less than 1, as compared with those with a ratio of greater than 1. In Group B a satisfactory diuresis was achieved without marked urinary potassium loss in those patients with a baseline urinary Na : K ratio of less than 1, whereas no diuresis was obtained in the two patients with a baseline urinary Na : K ratio of greater than 1. These results suggest that the measurement of the baseline urinary Na : K ratio is of help in determining the potential value of spironolactone in patients with resistant oedema.

Adult↗
PubMed1977

A comparison of phenformin and metformin in the treatment of maturity onset diabetes.

A comparison of the effects of two dose levels of phenformin (50 mg once and twice daily) and metformin (850 mg twice daily and 1,700 mg twice daily) has been undertaken in 24 maturity onset diabetics whose diabetes had remained inadequately controlled with dietary measures alone. Both biguanides effectively reduced the fasting blood sugar and body weight of the patients, metformin apparently having a greater effect on blood sugar than phenformin. Serum triglycerides were lower on the larger dose of metformin than on either dose of phenformin. Both drugs in the larger doses reduced the serum cholesterol. Side effects were more common with metformin, particularly in the higher dosage and overall control of the diabetes was achieved in the same proportion of patients (33%).

Adult↗
PubMed1976

Effect of pectin on serum lipids and lipoproteins, whole-gut transit-time, and stool weight.

Pectin (12g daily with meals) was taken by twelve healthy men aged 22-45 (mean 25 yr) for 3 weeks. This produced a statistically significant mean decrease in total serum-cholesterol of 0.48 +/- 0.18 mmol/1 (+/- S.E.M.)--i.e., 7.9 +/- 2.6%. The decrease was largely due to a reduction in serum-low-density-lipoprotein-cholesterol of 0.45 +/- 0.19 mmol/1 accompanied by a fall in serum-apolipoprotein-B of 0.11 +/- 0.04 g/1. During pectin administration wet stool weight increased from 150 +/- 10 to 186 +/- 15 g/24 h. There was no clear change in total serum-triglycerides, serum very low density lipoproteins, or in whole-gut transit-time.

Adult↗
PubMed1976

A comparison of methods for the immunoassay of serum apolipoprotein B in man.

Three assays for serum apolipoprotein B, radioimmunoassay, automated immunoprecipitation and rocket immunoelectrophoresis were compared. The antiserum used was raised against lipoprotein of density 1.040-1.053 g/ml (lipoprotein B). Each of the methods had a high degree of specificity when tested against potential interfering substances. The lowest levels of apolipoprotein B could be measured with radioimmunoassay but this sensitivity entailed the use of high dilutions of serum and resulted in a lower precision. Concentration response curves of lipoprotein B solution and serum were parallel for radioimmunoassay and automated immunoprecipitation but were not for rocket immunoelectrophoresis. Serum apolipoprotein B could be assayed by immunoelectrophoresis, however, if serum calibrated against the protein concentration of lipoprotein B solution by either of the other two methods was used as a secondary standard. Such a secondary serum standard also proved advantageous for all the methods because of the relative stability of the apolipoprotein B content of serum as compared to aqueous solutions of lipoprotein B. The mean apolipoprotein B concentration in 29 normolipaemic subjects aged 20-30 years was 0.84 +/- 0.12 g/1 (mean +/- S.D.) by radioimmunoassay, 0.85 +/- 0.11 g/1 by automated immunoprecipitation and 0.88 +/- 0.11 g/1 by rocket immunoelectrophoresis. The correlation between apolipoprotein B levels measured by the three methods was good. The ratio of serum cholesterol to serum apolipoprotein B was unaffected by individual differences in serum cholesterol or triglyceride levels. There was no significant difference between fasting and post-prandial serum apolipoprotein B concentrations. Radioimmunoassay is particularly suited to the measurement of low levels of apolipoprotein B, automated immunoprecipitation for large numbers of samples and rocket immunoelectrophoresis, when care is taken in the interpretation of results, for small numbers of samples.

Apoproteins↗
PubMed1976

Effect of phenobarbitone on plasma lipids in normal subjects.

1. Phenobarbitone in a dose of 180 mg daily was administered to ten normal subjects for 3 weeks. There was a significant increase in total plasma cholesterol, plasma low-density-lipoprotein cholesterol, plasma low-density-lipoprotein (LDL) triglycerides and plasma LDL protein. The increase in plasma LDL cholesterol accounted for the increase in total plasma cholesterol. There was a significant reduction in the ratio of LDL cholesterol to LDL protein. 2. No significant changes were observed in total plasma triglycerides, plasma very-low-density-lipoprotein (VLDL) triglycerides, plasma VLDL cholesterol or plasma VLDL protein. 3. Evidence that drug-metabolizing enzymes were induced by phenobarbitone was provided by an increase in antipyrine clearance. No relationship was observed between changes in plasma cholesterol and changes in antipyrine clearance. Serum gamma-glutamyl transpeptidase was also increased after phenobarbitone administration, the increase being unrelated to changes in antipyrine clearance or plasma cholesterol.

Adult↗
PubMed1976

Lack of effect on blood lipid and calcium concentrations of young men on changing from white to wholemeal bread.

1. When nineteen "free-living" male students, who normally ate 231 (SEM 14) g white bread/d changed to wholemeal bread for a 19-week period, there was no significant change in body-weight, plasma cholesterol or plasma triglyceride levels. These values, as well as plasma concentrations of calcium, phosphate, urate and haemoglobin, remained essentially the same as those for a control group. 2. Increasing the wheat-fibre intake by eating wholemeal bread is not an effective method for reducing blood lipids levels, at least in healthy young men with a moderate bread intake.

Adult↗
PubMed1976

Radioligand receptor assay of FSH.

The assay of FSH by a radioligand receptor assay (RLA) using homogenates of rat testicular tissue incubated for 17 h at 21 degrees C has been assessed. Chloramine-T or lactoperoxidase were used for iodination. The assay gave linear dose-response lines between 30 and 2000 ng sheep FSH/tube, and there was usually no major interference by LH. Two batches of labelled FSH, however, gave assays in which LH showed a striking interaction with FSH. When these batches were avoided and FSH and LH were mixed in ratios that differed less than fourfold, the assay was combined successfully, in the same tubes, with an RLA for LH, using LH and FSH labelled with 131I and 125I respectively. The RLA for FSH was not suitable for assay of FSH in rat serum because of apparent non-specific interference. Assay by RLA of rat FSH, in pituitary homogenates or released during incubation in vitro, gave results which were not closely correlated with those of either conventional bioassay or radioimmunoassay.

Animals↗
PubMed1975

Relationship between changes of serum cholecystokinin-pancreozymin and serum insulin after different stimuli.

The relationship between changes of serum immuno-reactive cholecystokinin-pancreozymin (CCK-PZ) and serum immuno-reactive insulin has been studied after various stimuli. The oral administration of 5 percent glucose or magnesium sulphate and the intra-duodenal administration of olive oil were all followed by a rise of serum CCK-PZ. The serum insulin rose after 5 percent glucose and also showed a small but insignificant rise with olive oil. There was, however, no change of serum insulin after the ingestion of magnesium sulphate suggesting that CCK-PZ in isolation does not stimulate insulin release.

Adult↗
PubMed1975

Comparison of the effects of ethinyl oestradiol and conjugated equine oestrogens in oophorectomized women.

Seventeen oophorectomized women were treated for 3 month periods, in random sequence, with ethinyl oestradiol 20 and 50 mug daily and conjugated equine oestrogens (Premarin)0-625 and 1-25 mg daily. The serum cholesterol, clot lysis time, plasma fibrinogen, platelet adhesiveness and activated partial thromboplastin time remained unchanged throughout the different oestrogen regimes. There was a significant rise of serum triglyceride levels on both doses of ethinyl oestradiol but no significant change with Premarin. Serum luteinizing hormone levels were depressed most by ethinyl oestradiol 50 mug daily, although no down to the levels in premenopausal women.

Adult↗
PubMed1975

Discrepancy between radioimmunoassay and radioligand-receptor assay of luteinizing hormone released in vitro by pituitary tissue from male rats of different ages.

Anterior pituitary glands from male rats aged 21, 40, 60 or 95 days were incubated in medium containing 0, 2 or 20 ng luteinizing hormone-releasing hormone (LH-RH)/ml. Incubates were assayed for LH by radioimmunoassay (RIA), by the radioligand-receptor assay (RLA) using testicular homogenates as the source of receptor and, in some instances, by the ovarian ascorbic acid depletion assay (OAAD). Irrespective of the dose of added LH-RH, glands from rats aged 40 and 60 days always showed a higher release of LH, as determined by RLA, than glands from animals aged 21 or 95 days. Measurement by RIA showed a similar pattern to RLA in the basal release of LH, but in the presence of LH-RH showed little difference in LH release by glands from rats aged 40, 60 or 95 days. The LH release caused by the higher concentration of LH-RH was always greater when measured by RLA than by RIA. Assay of comparable incubates by OAAD showed close agreement with RLA estimates in four incubations (mean index of discrimination 1.07; range 0.86-1.18) and consistent disagreement with RIA estimates (1.64; range 1.38-1.99). In contrast to the results with incubates, homogenates of pituitary glands from male rats of various ages showed close agreement of estimates by RLA, RIA and OAAD. These results suggest that RIA underestimates the LH-RH-stimulated release of LH in vitro from the male rat pituitary during some stages of sexual maturation.

Age Factors↗