Search PubMed⌕ Search

Biomedical subjects

H Meinertz

Publications and source records attributed to H Meinertz.

At least 37 records · Page 2Linked to original sources
PubMed1989

Soy protein and casein in cholesterol-enriched diets: effects on plasma lipoproteins in normolipidemic subjects.

The effect of dietary plant protein vs animal protein on plasma lipoproteins was investigated in a crossover study. Eleven normal subjects consumed formula diets containing 20% of calories as soy protein or casein, 27% as fat, and 53% as carbohydrate: the average cholesterol intake was 500 mg/d. After an initial decrease in plasma cholesterol and low-density-lipoprotein cholesterol (LDL-C) on both diets, the concentration of LDL-C stabilized during the soy-protein diet at a 16% lower level than on the casein diet (p less than 0.02) whereas the concentration of high-density-lipoprotein cholesterol (HDL-C) was 16% higher (p less than 0.01). In a similar earlier study with a cholesterol intake of less than 100 mg/d, casein and soy protein had indistinguishable effects on lipoprotein levels. Our two studies together suggest that the level of cholesterol intake may determine whether plant and animal dietary proteins have similar or different effects on plasma LDL and HDL concentrations.

Caseins↗
PubMed1988

Effects of soy protein and casein in low cholesterol diets on plasma lipoproteins in normolipidemic subjects.

Dietary plant proteins may lower plasma cholesterol and LDL concentrations in hypercholesterolemic patients when substituted for animal proteins, particularly in diets with low cholesterol and saturated fat content. Plant protein diets appear, however, to be without effect on plasma lipoprotein levels in normal subjects. In the present study, we have examined whether the origin of the dietary protein, i.e. plant (soy) or animal (casein), affects the plasma lipoproteins in normolipidemic subjects when these proteins are presented as components of diets low in cholesterol and saturated fat. The study followed a crossover design. Five men and 5 women consumed liquid formula diets containing 20% of calories as casein or soy protein, 28% as fat (mainly monounsaturated), and 52% as carbohydrate; the intake of cholesterol was less than 100 mg per day. The two dietary periods, each of 1 month duration, were separated by an interim period of 1 month on self-chosen food. Following an initial 30% reduction of cholesterol and LDL plasma levels on both diets, the concentrations of each of the major lipoprotein classes (VLDL, IDL, LDL, HDL2 and HDL3) were similar during the two experimental dietary periods. Body weights were essentially constant. Dietary soy protein and casein could not be distinguished in their effects on the plasma concentrations and chemical composition of the major lipoprotein classes in normolipidemic subjects.

Adult↗
PubMed1988

Anti-sperm antibodies and immune subfertility.

A brief description of immune subfertility, caused by antibodies directed against sperm-specific glycoproteins in the sperm membrane, is given. Observations during the last few years have indicated that this immune disease is primarily caused by anti-sperm antibodies of the IgA class, and recent results from vasovasostomized men lend further support to this theory. Detection of anti-sperm antibodies should therefore include characterization of the immunoglobulin class of antibodies. In male patients this can be achieved by direct mixed anti-globulin reaction test or immunobead-binding test on the patients' spermatozoa, and in female patients cervical mucus can be tested by indirect versions of the same tests.

Antibodies↗
PubMed1988

Detection of antisperm antibodies on the surface of motile spermatozoa. Comparison of the immunobead binding technique (IBT) and the mixed antiglobulin reaction (MAR).

Investigators testing for antisperm antibodies have recently focused on tests that detect the Ig classes of the sperm-bound antibodies. The aim of this study was to compare the sensitivity of two of these tests, viz. the immunobead binding technique (IBT) and the mixed antiglobulin reaction (MAR). Twenty-one male or female sera were tested for IgG and IgA antisperm antibodies with the IBT and the MAR. The sera were selected on the basis of the IBT results, and the MAR was carried out without knowledge of these results. For IgG antisperm antibodies, there was a highly significant correlation between the two tests (P = 0.0043), whereas, for IgA antisperm antibodies, the correlation was poor (P = 0.2951), because the IBT revealed a positive reaction for IgA in sera in which no such antibodies could be detected by the MAR.

Autoantibodies↗
PubMed1987

Indirect mixed antiglobulin reaction (MAR) as a screening procedure for antisperm antibodies. I. Methodological studies.

Direct mixed antiglobulin reaction (MAR) cannot always be carried out because it requires motile spermatozoa in the patient's ejaculate. Therefore, the indirect MAR for IgG and IgA using donor spermatozoa sensitized with serum or seminal plasma from patients was investigated with the aim of developing a practical screening procedure for antisperm antibodies involving a characterization of the Ig-class of the antibodies. Samples from 23 men, 13 men with and 10 men without agglutinating antisperm antibodies, were used for the methodological experiments with the indirect MAR. Among three procedures to diminish the amount of nonbound immunoglobulin after sensitizing the donor spermatozoa with serial dilutions of serum or seminal plasma, a swim-up method was found to be optimal. The indirect MAR was carried out with glutaraldehyde-fixed sheep erythrocytes coated with IgG or IgA and various dilutions of anti-IgG and anti-IgA, respectively. These experiments led to a standardization of the indirect MAR, making it sensitive, easy to read, and allowing the reactions for IgG and IgA to be compared on an approximately equimolecular basis.

Autoantibodies↗
PubMed1987

Indirect mixed antiglobulin reaction (MAR) as a screening procedure for antisperm antibodies. II. Clinical studies.

In this study the question was raised whether the indirect mixed antiglobulin reaction (MAR) using donor spermatozoa could substitute the direct MAR requiring motile spermatozoa in the patient's ejaculate in the screening for antisperm antibodies. Serum and seminal plasma from 48 men selected on the basis of the results in the direct MAR were tested by the indirect MAR. Both tests were carried out for IgG and IgA antisperm antibodies. A statistically significant correlation was found both between the sperm-bound IgG and the free IgG antisperm antibodies in serum as well as in seminal plasma and between sperm-bound IgA and the free IgA antisperm antibodies in seminal plasma whereas no correlation was found between the sperm-bound IgA and the free IgA antisperm antibodies in serum. This finding strongly supports the concept that the major part of the IgA antisperm antibodies in the ejaculate are locally produced.

Antigen-Antibody Reactions↗
PubMed1987

Intestinal cholesterol absorption in the chyluria model.

Isotopic methods for the measurement of dietary cholesterol absorption were compared with the lymph cholesterol balance procedure in filarial chyluria patients. After a single intravenous injection of radioactive cholesterol, absorption was found to be 746 +/- 136 mg/day by method I, which is based upon the fecal endogenous neutral steroid mass measurement, and 471 +/- 135 mg/day by the simultaneously measured lymph/plasma ratio of cholesterol specific activity (dpm/mg). The corresponding value, determined as the difference between lymph cholesterol transport on a cholesterol-containing diet (1500 mg) and on a cholesterol-free diet, was 622 mg/day. When radioactive cholesterol (1487 mg/day) was fed daily to a second patient, absorption determined by isotopic fecal recovery (353 mg/day) matched that obtained by the lymph balance procedure (326 mg/day). Transudation of plasma cholesterol into the intestinal lymph, estimated by the single intravenous injection of radioactive beta-sitosterol, was independent of both the luminal content of plant sterols and the absorption of dietary cholesterol. The absorption of endogenous cholesterol was calculated by: 1) subtracting the cholesterol originating from plasma (transudation) together with the absorbed dietary cholesterol found in lymph from the total mass of cholesterol transported in lymph, and 2) the lymph balance method, i.e., after interrupting the endogenous cholesterol mucosal uptake by beta-sitosterol feeding (9 g/day) while on a cholesterol-free diet. Endogenous cholesterol was preferentially absorbed compared to dietary cholesterol, but there was no competition for absorption. The major portion of dietary cholesterol found in lymph was esterified, but esterification was not a prerequisite for absorption.

Adult↗
PubMed1986

Detection of autoimmunity to sperm: mixed antiglobulin reaction (MAR) test or sperm agglutination? A study on 537 men from infertile couples.

Two different ways of testing for antisperm antibodies were compared: the mixed antiglobulin reaction (MAR) test for demonstration of antibodies of the IgG and IgA classes bound in vivo to the sperm membrane antigens and the gelatin agglutination test for detection of nonbound antisperm antibodies in serum and seminal plasma. Samples from 537 men from infertile couples were investigated. Antibodies bound to the sperm membrane were detected in 49 men (9.1%), IgG in 44 (8.2%), and IgA in 38 cases (7.1%). Sperm agglutinins were recorded in seminal plasma from 30 men (5.6%) and in serum (titer greater than or equal to 16) from 43 men (8.0%). The investigation revealed a very close correlation between the results of MAR testing and the occurrence of sperm agglutinins in serum and seminal plasma. However, if one focuses on antisperm antibodies of the IgA class, which seem to play the major role in male immune infertility, the MAR test offered the advantage that a minor group of patients with pure IgG responses could be distinguished, and rare cases with mainly or exclusively locally produced IgA antibodies could be detected.

Autoantibodies↗
PubMed1986

High-density lipoprotein cholesterol assay by magnesium dextransulphate precipitation.

A method for determination of high-density lipoprotein cholesterol (HDL-C) is evaluated: after precipitation of low and very low lipoprotein cholesterol in serum by magnesium dextransulphate, HDL-C is determined by an enzymatic method. The precision of the method was good: coefficient of variation 4%. The accuracy was good, evaluated by correlating HDL-C results from the present assay to the results obtained from three other HDL-C assays (n = 17): ultracentrifugation r = 0.91, phosphotungstate/MgCl2 r = 0.98, and alpha-lipoprotein determination by electrophoresis r = 0.91 (p less than 0.01). Repeated analysis showed that serum may be kept at 4 degrees C for 1 month, at -20 degrees C for 2 months, and requires -80 degrees C for longer storage. Ten patients with acute myocardial infarction showed significantly lower HDL-C from day 4 in the acute phase and during the first 3 months follow up (p less than 0.05). Eighty patients with peripheral vascular disease, who were compared to a group of matched controls, also showed significantly decreased serum HDL-C (p less than 0.01). The present HDL-C assay is easy, fast and reliable and is considered a valuable clinical test.

Adult↗
PubMed1985

High-carbohydrate, low-fat diet: effect on lipid and carbohydrate metabolism, GIP and insulin secretion in diabetics.

The effects of increasing the dietary polysaccharide content from the customary 40 percent to 50 percent of total energy intake were examined in a metabolic ward-cross-over study of eight noninsulin dependent diabetic patients with normal fasting C-peptide concentration. The aim was to study the effect of a raised carbohydrate content; therefore, the fibre content of the diet was kept approximately constant. Patients had been treated with diet alone, and the high carbohydrate (HC) observation period lasted for two weeks. Blood glucose was significantly increased postprandially in the HC period (11.8 +/- 0.3 versus 10.7 +/- 0.4 mmol/l), and this was accompanied by significantly raised immunoreactive insulin (IRI) concentrations. The secretion of IRI, C-peptide and gastric inhibitory polypeptide (GIP) after a standard meal-challenge at the end of each period were unaffected by the preceding diets. The HC diet was accompanied by increasing values of plasma triglyceride (1.13 +/- 0.06 versus 0.97 +/- 0.06 mmol/l) and VLDL-triglyceride (0.69 +/- 0.04 versus 0.50 +/- 0.04 mmol/l), whereas the ketone body concentration was decreased (0.25 +/- 0.03 versus 0.36 +/- 0.05 mmol/l). Both HDL- and LDL cholesterol were decreased by the HC-diet (1.07 +/- 0.02 versus 1.18 +/- 0.02; 3.45 +/- 0.09 versus 3.89 +/- 0.09 mmol/l, respectively), while the LDL to HDL cholesterol concentration ratio remained unaffected. Thus, in two weeks, a HC diet resulted in hyperglycaemia, hyperinsulinaemia, hypertriglyceridemia and a state of antiketogenesis, without any apparent change in the capacity of mealinduced insulin release. LDL- and HDL-cholesterol were lowered to the same extent.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

DNA sequences flanking the insulin gene on chromosome 11 confer risk of atherosclerosis.

The allelic frequency of DNA restriction fragments of a large size class (U alleles) in the polymorphic region flanking the 5'-end of the human insulin gene on chromosome 11 was 2 X 5 times higher in a group of patients with extensive atherosclerosis than in subjects in whom atherosclerosis could not be demonstrated by coronary arteriography and careful clinical examination. The U alleles apparently do not confer risk of atherosclerosis through conventional risk factors such as body weight or blood pressure or levels of blood glucose, triglycerides, cholesterol, or lipoproteins.

Adult↗
PubMed1984

Serum lipoproteins after treatment with verapamil for 6 months.

Fasting levels of serum lipids and lipoproteins were measured in survivors of acute myocardial infarction after 6 months of treatment with placebo (n = 19) or verapamil 360 mg daily (n = 13). There were no significant differences between the groups and values had not changed in the verapamil group 2 weeks after cessation of treatment.

Adult↗
PubMed1982

Effects and side-effects of partial ileal by-pass surgery for familial hypercholesterolaemia.

Ten patients with familial hypercholesterolaemia were subjected to partial ileal by-pass surgery. Plasma cholesterol fell by 41 and 38% and low-density lipoprotein cholesterol by 51 and 46% after six and 18 months respectively. High-density and very low-density lipoprotein cholesterol and plasma triglycerides were unaffected. Alanine aminotransferase increased transiently in half of the patients. Diarrhoea and slight steatorrhoea troubled most of the patients for the duration of 18 months' period of observation. Other long-term side effects were slight but significant increase in the renal excretion of oxalic acid and reduction in the intestinal absorption of calcium. The study shows that this operation has metabolic side-effects that warrant continued medical care of these patients.

Adult↗
PubMed1982

Coated pits and pinocytosis of cationized ferritin in human skin fibroblasts.

Pinocytosis was studied in cultured human skin fibroblasts in order to obtain more information about uptake in these cells of non-specific ligands with different net surface charge. The fibroblasts were obtained from a normal person and a patient homozygous for familial hypercholesterolemia. No ultrastructural differences were observed between the two cell types. The ratio between coated and smooth pits at the cell surface was about 1:6. Freeze-fracture revealed that whereas smooth pits were devoid of intramembrane particles, the coated pits occupying 1-5% of the total cell surface area showed numerous intramembrane particles. Cationized ferritin (pI = 8.5) bound to the cell surface and to coated pits of both types of fibroblasts at 4 degrees C. Either type internalized CF at 37 degrees C. Vacuoles (lysosomal elements) containing CF were seen already after 5 min at 37 degrees C, but were much numerous after 30 min of incubation at 37 degrees C, and appeared with the same frequency in both cell types. Smooth (uncoated) pits at the cell surface remained unlabeled. In contrast to CF, native ferritin (pI = 4.6) was internalized to a very limited extent in both cell types, even after 3.5 h of incubation at 37 degrees C. These results indicate that both normal and FH fibroblasts internalize CF exclusively by coated pits, and adsorptive uptake mechanism that apparently is nonspecific but clearly cation-selective.

Adolescent↗
PubMed1981

Excessive hypertriglyceridemia and pancreatitis in pregnancy. Association with deficiency of lipoprotein lipase.

Acute pancreatitis verified at laparotomy occurred in the 37th week in 1 of 4 women who developed excessive hypertriglyceridemia (type V hyperlipoproteinemia) during pregnancy. The hypertriglyceridemia was associated with and possibly caused by deficiency of lipoprotein lipase, measured as the NaCl sensitive component of post-heparin lipase activity. A severely fat-restricted diet controlled the hypertriglyceridemia in 1 of the patients, followed during a second pregnancy.

Adult↗