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Biomedical subjects

D Seidel

Publications and source records attributed to D Seidel.

At least 253 records · Page 14Linked to original sources
PubMed1978

An improved and simple micro-method of sphingomyelinase assay in leukocytes and urine.

A simple one-vial-method was developed for the quantitative determination of sphingomyelinase activity in human leukocytes and urine, using [14C-methyl] sphingomyelin. The measured activities of healthy control persons show a higher scatter in (n=50) urine (1.2 +/- 0.5 nmol/h . ml urine) than in (n=9) leukocytes (2.15 +/- 0.35 nmol/h . mg protein). Long term tests showed that the enzyme activities in urine can best be correlated to the 24-h-creatinine excretion. A distinct loss of enzyme activity was found in dialyzed urine starting at about the third day; this did not occur in undialyzed urine. The method also shows good reproducibility in micro-tests. It is therefore suitable for screening tests (urine of persons suffering from Niemann Pick disease) and for the prenatal diagnosis of sphingomyelinosis. For one out of two children with symptoms of sphingomyelinosis (hepatosplenomegaly, mental retardation, and neurological deterioration) the diagnosis was confirmed by morphological examination of tissues obtained by biopsy. In both cases leukocytes and urine revealed normal sphingomyelinase activity. These biochemical results in conjunction with the clinical and morphological picture were indicative of type C Niemann-Pick disease.

Adult↗
PubMed1978

[Clinical, preclinical and prenatal diagnosis of congenital sphingolipidoses by determining lysosomal hydrolases (author's transl)].

Sphingolipidoses in infancy and adulthood and associated metabolic disturbances are caused by a recessively inherited, circumscribed lysosomal enzyme deficiency in the catabolism of various structural tissue substances. After presenting detailed methods for the quantitative assay of activities of lysosomal hydrolytic enzymes in leukocytes, serum , fibroblasts, urine and organ tissue with the aid of synthetic chromogenic and fluorescent substrates the signigicance of these methods for clinical diagnosis, for the detection of homozygote persons before developing clinical symptoms (preclinical diagnosis), for the preventive prenatal diagnosis and forthe detection of heterozygote carriers is described for the following diseases: Deficiency of hexosaminidase A and B, deficiency of beta-glucosidase, deficiency or arylsulfatase A, deficiency of alpha-galactosidase, deficiency of alpha-glucosidase.

Clinical Enzyme Tests↗
PubMed1977

Isolation and characterization of lipoprotein-X from the pig.

In vitro incubation of pig bile with pig whole serum resulted in the formation of "LP-X like" material migrating towards the cathode on agar-gel electrophoresis. As in all other species studied so far, LP-X occurred also in the serum of bile duct ligated pigs, however, relatively late (48-72h) after the operation. In parallel, alterations of some serum parameters and of the protein-lipid composition of the different lipoporotein fractions were observed. While the electrophoretic behaviour, the protein-lipid and apoprotein composition of pig LP-X were comparable to those found in man, dog and rat, it sedimated in most instances at the density 1.063 g/ml.

Alkaline Phosphatase↗
PubMed1977

[Studies on the structure and metabolism of lipoprotein-X (LP-X), the abnormal plasmalipoprotein in cholestasis (author's transl)].

Recent results regarding the pathophysiology of hyperlipoproteinemia in cholestasis are reported. The isolation of an abnormal lipoprotein (Lipoprotein-X; LP-X) from the plasma of cholestatic patients was achieved by a combination of various physico-chemical techniques. Most of the plasmacholesterol in these patients is transported in form of this abnormal lipoprotein which is very rich in phospholipids and unesterfied cholesterol. LP-X represents a vesicle with a mean diameter of 700 A. Albumin takes part as a structural protein of the particle. Besides albumin, which seems to be located in an internal water compartment or to be covered with lipids. Apo-C and Apo-D are present as surface proteins. The lack of Apo-B in LP-X, the major apoprotein of normal low density lipoproteins, seems to be the reason for a disturbed endogenous feedback mechanism of hepatic cholesterol synthesis, which is strongly increased in cholestasis. The high specificity and power of the LP-X test as clinical-chemical parameter to demonstrate or exclude cholestasis finds its explanation in our knowledge about the origin of this abnormal lipoprotein in cholestasis. LP-X is formed when a lipoprotein normally excreted with the bile refluxes into the plasma stream to convert into LP-X. This formation depends only on certain physico-chemical requirements and is independent of an energy-providing or enzymatically regulated process. The biological halflife of LP-X is similar to that of normal plasmalipoproteins. However, enzymes of postheparin plasma as well as the lecithin: cholesterol acyltransferase do not seem to play a major role in the catabolism of lipoprotein-X, but only change some of the physicochemical characteristics of this vesicle.

Animals↗
PubMed1977

[Arcus senilis].

Explore the source record for details and available documents.

Adult↗
PubMed1977

[Diurnal patterns of plasma lipids and lipoproteins in primary endogenous hypertriglyceridemia (type IV-hyperlipoproteinemia) (author's transl)].

Acute and chronic effects of three isocaloric diets on plasma lipids and plasma lipoproteins were studied in 10 patients with primary endogenous hypertriglyceridemia (type IV-hyperlipoproteinemia). The diets used contained 20% protein, 50, 37 and 1% fat and 30, 43 and 79% carbohydrates respectively. Cholesterol levels were similar with all diets. Fasting values of plasma triglycerides were lower with the fat-containing diets compared to the high-carbohydrate diet. Diurnal patterns, however, were significantly higher with the former diets in 8 of the 10 patients. Postprandial lipoprotein patterns on fat-containing diets are characterized by chylomicronemia and marked changes of concentration and composition of other lipoprotein classes. If, analogous to diabetic therapy, control of hypertriglyceridemia is meant to imply low all-day levels rather than low fasting levels, a rather low-fat, high-carbohydrate diet seems to be superior in most patients with endogenous hypertriglyceridemia to diets containing more than 35 calorie per cent of fat.

Cholesterol↗
PubMed1977

Serum 25-hydroxycalciferol in myocardial infarction.

Oral intake of calciferol (vitamin D) was higher in patients with myocardial infarction than in controls. Having established an assay for 25-hydroxycalciferol (25-OH-D), the principal circulating form of the vitamin, we measured this compound in control subjects and patients with myocardial infarction. In controls, 25-OH-D varied with the season: levels were high in summer and low in winter. Furthermore, levels were low in control subjects above 60 years of age. In patients with myocardial infarction, normal and low values for 25-OH-D were found. It is concluded that in this region patients with myocardial infarction do not consume greater amounts of vitamin D.

Adolescent↗
PubMed1977

Adult metachromatic leukodystrophy. I. Clinical manifestation in a female aged 44 years, previously diagnosed in the preclinical state.

In a 5-year follow-up of a case of adult metachromatic leukodystrophy, already diagnosed in the preclinical stage, the development of the symptoms of this disease could be studied in detail: initially, lack of drive, emotional lability and depressive mood. At the same time, pain in the arms and beginning gait disturbance. Later, impairment of memory and concentration, disorientation, inadequate behavior and progression of gait disturbance. Finally spastic atactic gait with small steps and dyspractic components, coordination disturbances with writing dysfunction, fast dysarthric speech, hyperkinetic activity, compulsory emotional outbursts and progressive dementia. Only minor neurological signs such as reflex abnormalities. In the EEG, slight slowing of frequencies compared to earlier tracings. Increasing diminution of nerve conduction velocity in the lower limbs. Only minor increase of CSF protein (51 mg%). In spite of normal vision, evoked visual potentials abnormal, response of optical and electrical blink reflexes delayed. Imperfect filling of gallbladder. No significant quantitative changes of the biochemical parameters compared with the findings made 5 years earlier (excretion of urinary sulfatides, diminished activity of arylfulfatase A in urine and leukocytes).

Adult↗
PubMed1977

Improved assessment of plasma lipoprotein patterns. III. Direct measurement of lipoproteins after gel-electrophoresis.

Based on a previously described technique [Clin. Chem. 19, 737 (1973)] of precipitating plasma lipoproteins with polyanions after their electrophoretic separation in gels, a new method is presented for measuring normal plasma lipoproteins densitometrically. The method is fast and easy; the CV for beta-, pre-beta-, and alpha-lipoproteins was less than 5% in one series. Results are linearly related to concentration up to 10 g of total lipoprotein per liter. No unusual equipment is required. Standardization is done with the aid of a commercially available filter. Total plasma cholesterol and cholesterol calculated from quantified lipoprotein fractions were highly (r = 0.963) correlated.

Adult↗
PubMed1976

On the metabolism of lipoprotein-X (LP-X).

The characteristic low-density lipoprotein of cholestasis (LP-X) earlier described for humans is found with identical properties in dogs and rats after experimental cholestasis. After ligation of the common bile duct, LP-X may be detected in the plasma within the first 20 hours. A period of marked increase in concentration is followed by decreasing plasma concentrations and LP-X becomes undetectable 7-10 days after ligation of the bile duct in rats. High plasma bile salt concentration may alter the structural integrity of LP-X and may in part be responsible for its disappearance after long-lasting and severe biliary obstruction. Plasma decay curves for isolated LP-X injected intravenously into healthy animals revealed a rapid early fall in concentration followed by a gradual decline. The calculated fractional catabolic rate of LP-X was found to be 0.450 +/- 0.069 for dogs and 1.553 +/- 0.096 for rats corresponding to a mean biological half life of 37.7 +/- 6.4 h or 10.7 +/- 0.6 h, respectively. In vitro LP-X degradation occurs in post-heparin plasma, however, it seems to be too early to speculate on the enzyme activity and on the mode of action responsible for this disappearance.

Animals↗
PubMed1976

Topography of human urokinase activity in renal tissue.

Frozen sections of human kidneys were studied with a modified technique after TODD [22] )fibrinogen slides). Urokinase activity could be demonstrated in the juxtamedullary region (venae arcuatae, venae interlobulares, vasa recta) and in the epithelium of the calyces. Urokinase activity was specifically blocked by highly purified urokinase antibodies.

Animals↗
PubMed1976

Formation of lipoprotein-X. Its relationship to bile compounds.

In this study we have demonstrated that in native bile, lipids are organized in the form of a lipoprotein (bile LP) carrying albumin as apoprotein. The lipid composition of bile LP is almost identical to lipoprotein-X (LP-X, the characteristic lipoprotein of cholestasis). However, it differs from LP-X inits protein/lipid ratio and immunological and electrophoretic characteristics. Bile lipoprotein can be converted into "LP-X-like" material in vitro by adding albumin or serum to native bile. The LP-X-like material formed in vitro has physicochemical and chemical characteristics similar or identical to LP-X isolated from serum. As bile lipoprotein can be converted into LP-X-like material by the addition of albumin to bile, LP-X can be converted into bile-LP-like particles by adding bile salts to a LP-X-positive serum. Furthermore, experimental connection of the common bile duct to the vena cava is followed after a few hours by the appearance of LP-X-like material in the plasma. These facts taken together strongly suggest that bile LP is a precursor lipoprotein for LP-X and that it refluxes into the plasma pool under cholestatic conditions.

Animals↗