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Biomedical subjects

H David

Publications and source records attributed to H David.

At least 109 records · Page 6Linked to original sources
PubMed1985

[Clinical liver transplantation in East Germany].

In the GDR 28 liver transplantations have been performed up to now. The 1 year survival rate amounts to 30%. At present 8 patients are alive between 3 months and 5 years. There were no biliary complications since the biliary reconstruction was performed by using a special 'mucosa suture'-technique. Ischaemic graft failure was a main cause for early postoperative mortality. A better immunosuppressive treatment may help to improve the results of liver transplantation in future.

Adult↗
PubMed1984

[Value of histopathologic findings following liver transplantation based on biopsy course studies].

A total of forty-four biopsies from nine liver transplantation patients, who had developed complications postoperatively, were studied histologically and, in part, electron-microscopically. Morphologic signs of acute rejection were seen in three patients, while there were indications of chronic rejection in one patient. In combined lesions, such as drug-induced hepatosis, cholangitis, hepatitis, and rejections, the interpretation of biopsy findings may be difficult, and special entities cannot in every case be separated unequivocally. Changes of serum bilirubin and of serum enzyme activity do not run entirely parallel to the microscopically detectable structural lesions. For diagnosis of complications after liver transplantation both the morphologic and the clinical findings must be considered.

Adult↗
PubMed1984

[Digital tenosynovitis caused by non-tuberculous mycobacteria. Apropos of the 4th case caused by Mycobacterium terrae].

A 75 year old man developed chronic flexor tenosynovitis in a finger, caused by Mycobacterium terrae. He had a history of diabetes mellitus and arteritis, but not of local trauma. However, triamcinolone had been injected into the tendon sheath on 3 occasions. Chemotherapy was instituted, but after 3 months amputation became mandatory. This is the fourth case reported in which M. terrae was involved, and it supports the responsibility of this organism as a human pathogen. Attention is drawn to the hazards of corticosteroid injections into tendon sheaths.

Aged↗
PubMed1984

Morphometric study on the absolute volume of differentiating hepatocytes in rats.

Quantitative changes in the mean absolute volume of rat hepatocytes during prenatal development were studied by light microscopic stereological methods. Combining these light microscopic measurements with electron microscopic relative volume (volume density) data (Daimon et al. 1982) enabled the evaluation of the mean absolute volumes of cytoplasmic organelles of fetuses and newborns. On the 15th day of gestation the mean absolute volume of hepatocytes was 1,523 +/- 10.7 microns3. After 3 days hepatocytes were enlarged 66.2% (2,531.5 +/- 108.2) and at birth 157.1% (3,915.6 +/- 190.8). The comparison of the absolute volume and the volume density of each cell organelle made possible the interpretation of much functional and morphometric data of the development of hepatocytes.

Animals↗
PubMed1983

Conversion of sterols and triterpenes by mycobacteria. I Formation of progesterone and 1-dehydroprogesterone from Mycobacterium aurum, strain A+.

Side-chain degradation of sterols by bacteria is known to proceed via oxidation of a terminal methyl group followed by a succession of beta-oxidative steps. By this pathway, the pregnane backbone is not produced. However, examination of cholesterol degradation products using a strain of Mycobacterium aurum shows that progesterone and 1-dehydroprogesterone are present at low levels. These pregnane derivatives were identified by gas-liquid chromatography combined with mass spectrometry. This indicates that an alternative pathway for sterol side-chain degradation occurs in bacteria, which could be of great interest for the biological production of corticosteroid precursors.

Cholesterol↗
PubMed1983

Precursors of monoamine-storage organelles in developing megakaryocytes of the rat.

Identification and distribution of the precursors of amine-storage organelles in rat megakaryocytes during cell maturation were studied, using the uranaffin reaction for adenine nucleotide. The precursors of the amine-storage organelles appeared as 200-300 nm vesicles having an uranaffin electron dense granule, whereas they appeared as empty vesicles by conventional glutaraldehyde-OsO4 fixation. X-ray probe microanalysis confirmed the existence of U and P in the uranaffin reaction positive vesicles. The precursors appeared in the immature megakaryocytes, especially at the trans(mature) face of the Golgi apparatus, and rapidly increased in number in the maturing cells. The size of the uranaffin granules in the precursor organelles increased gradually during cell maturation and became almost equivalent to the dense body of blood platelets in the final stage of cell maturation.

Adenine Nucleotides↗
PubMed1983

Populations of megahepatocytes and minihepatocytes and their components in livers of old rats.

Principally, morphometric investigations of the liver refer to mononuclear hepatocytes. They do not consider the polyploidy nor the bi- and multinuclearity of mainly old organs. Using a specially developed method we determined volume density, volume and number of cell components of individual hepatocytes. In relation to the mean volume of hepatocytes of 24 and 27 months old female Wistar rats (14,305.2 +/- 1,708.6 micronsM3 and 17,091.1 +/- 1,405.5 micronsM3, respectively) the characteristic quantitative values of minihepatocytes (16.7-48.9% of the mean value) and of megahepatocytes (140.2-204.8% of the mean value) are demonstrated.

Aging↗
PubMed1983

Quantitative ultrastructure of the rat liver by immersion and perfusion fixations.

Morphometric and qualitative investigations of rat liver with immersion fixation (I) and perfusion fixation (P) have not produced any statistically significant differences in the volume densities and numbers per area of elements of hepatocytes: Vv mitochondria: 0.194 (I), 0.189 (P); peroxisomes 0.011 (I), 0.012 (P); glycogen 0.196 (I), 0.183 (P); agranular endoplasmic reticulum 0.144 (I), 0.183 (P); granular endoplasmic reticulum and groundplasm 0.455 (I), 0.437 (P). The numbers per unit area (micrometers 2) for the mitochondria are 0.492 (I) and 0.496 (P), and for the peroxisomes 0.048 (I) and 0.044 (P), respectively. From the results, the following conclusions can be drawn: -- There are no differences in qualitative and quantitative findings as to the preservation of the hepatocytes by immersion and perfusion fixation. Immersion fixation can be applied as analogous and equivalent methods in routine investigations of human excision and bioptic tissues and also of very large and very small organs. -- Ischemic autolytic alterations of the cells, especially in the mitochondria occur: with immersion fixation in the surface zone and the central zone of the specimen (the intermediate zone is well preserved), with perfusion fixation in different areas. -- Alterations in the sinusoidal wall affect the width of the lumen and the openings of the endothelial cells which show better conditions at optimum pressure and flow rate of the perfusion fluid. -- Pronounced alterations in the endothelial cells, partially the total destruction and detachment are caused by non-optimal pressure and flow rates of the perfusion. They may appear, however, as secondary results caused by the composition of the fluid or circumscribed constrictions of the vascular system of the liver. -- With regard to the transplantology of the liver the studies on the perfusion fixation demonstrate the importance of pressure, flow rate and composition of the perfusion fluid for preserving the tissue, especially the sinusoidal wall.

Animals↗
PubMed1983

[Cell cycle dependent changes of the cellular ultrastructure].

A survey of the cell ultrastructure studies during G- and S-phases shows that the few findings known so far do not suffice to formulate a general conclusion. In the spindle area the specific cell structure is dedifferentiating during the mitotic cycle. Outside the spindle area the specific cell structures may remain intact partly or in full. It can be concluded from this fact that cellular proliferation and the process of specific cell functions do not exclude each other but may happen simultaneously.

Cell Cycle↗
PubMed1983

[Endoscopic polypectomy of the stomach].

As a result of selective biopsy of gastric polyps 77 hyperplastic, 36 hyperplasiogenous and 11 adenomas were found. By the introduction of endoscopic polypectomy 42 polyps were resected in toto and 39 could be removed. The histological result of the whole polyp showed that the most frequent form is the hyperplastiougenous type with 42.5%. Comparisons of the histological results of the whole polyp with the particles of the biopsy (selective biopsy) differ in 40%. The combination of the results of antral polyposis (type II) with those of an adenocarcinoma in the material affirmed our thesis that the hyperplasiogenous polyp is an indicator for a higher tendency of the gastric mucosa for developing a carcinoma. Follow-up observations of pseudopolypoid folts showed a spontaneous regression of about 50% after one year and of about 75% after four years. In this article tendencies regarding the relation between the patients age, the growth speed and the histological structure of the gastric polyps are discussed.

Adenoma↗
PubMed1982

Correlated ultrastructural and morphometric studies on the liver during prenatal development of rats.

Quantitative and qualitative changes in liver tissues during prenatal development were studied by electron microscopy and morphometry. On the 15th day, 30% of fetal liver volume consisted of hepatocytes, and the extrahepatocytic spaces amounted to 63%. The hemopoietic cells occupied 93% of the extrahepatocytic spaces. Immature bile canaliculi were observed and amounted only to 0.14% of extrahepatocytic spaces. The hepatocytes were irregular in shape and possessed several large lipid droplets which amounted to 19% of the cytoplasm. Although the rough surfaced endoplasmic reticulum (RER) was well developed, the smooth surfaced endoplasmic reticulum (SER) was not yet differentiated. The typical peroxisomes with nucleoid and glycogen were not observed in the cytoplasm. On the 18th day the volumetric densities of hepatocytes and bile canaliculi were increased. The typical peroxisomes with nucleoid appeared in the cytoplasm. The accumulation of glycogen which amounted to 12% of the cytoplasmic volume had taken place, while the volume of lipid droplets decreased significantly. In glycogen areas the differentiation of SER began. At birth the histogenesis of the liver was well established. The hemopoietic cells decreased in number and were confined to perisinusoidal spaces. The volumes of biliary capillaries and sinusoids were comparable with these of young rats now. The volumetric density of hepatocytes increased and occupied about 74% of the liver. The volumetric densities of mitochondria, SER, peroxisomes, secondary lysosomes, and lipid droplets increased significantly in comparison with those of the 18 days old fetus, while RER, Golgi area, and primary lysosomes were rather constant. The volumetric density of glycogen decreased rapidly at birth.

Adult↗
PubMed1982

Hydrolysis by human alpha-amylase of p-nitrophenyloligosaccharides containing four to seven glucose units.

Kinetic and "high-pressure" liquid-chromatographic studies were performed on the reaction of human pancreatic and salivary alpha-amylase (EC 3.2.1.1) with p-nitrophenyloligosaccharides containing four to seven glucose units. The kinetic studies indicate that, as the temperature increases from 25 to 37 degrees C, the apparent Km of the enzyme for a given substrate increases slightly. However, as the number of glucose units in the substrate increases, the apparent Km decreases. The apparent Vmax increases as the temperature increases, and decreases as the number of glucose units in the substrate increases. In contrast, chromatographic data indicate that the relative rate of hydrolysis by alpha-amylase is pG7 greater than pG6 greater than pG5 greater than pG4. The differences between the kinetic and the chromatographic results are discussed. p-Nitrophenyl-alpha-maltopentaoside and p-nitrophenyl-alpha-maltohexaoside are superior to the other p-nitrophenyloligosaccharides as substrates for determining alpha-amylase activity in an alpha-glucosidase-coupled assay system.

Amylases↗
PubMed1982

p-Nitrophenylglycosides as substrates for measurement of amylase in serum and urine.

Pantrak E.K. (endpoint and kinetic) Amylase reagent (Calbiochem-Behring) is the first commercially available alpha-amylase reagent in which p-nitrophenyl-d-glycosides are used as the substrate. We describe the effect of reagent composition on reagent performance. The reagent performance compares well with that of Amylochrome reagent (Hoffmann-La Roche), Du Pont aca, and Beckman D.S. amylase reagents in assays of sera and urines. We detected no interference from increased concentrations of glucose or pyruvate in the sample. The reagent can be used in either a manual fixed-time or an automatable kinetic assay.

Amylases↗
PubMed1982

[Improved protection of the myocardium with a combination of intra-aortic balloon counter-pulsation and aimed substrate administration in acute myocardial infarct--a comparative study].

In comparative studies in 36 mongrel dogs it was tried to find out how far intraaortic balloon pumping (IABP) applied solely and in combination with glucose-insulin-potassium (GIK) might influence the degree of acute myocardial ischemia. The ischemia lasted 3 hours. After 60 min myocardial ischemia IABP, the isolated GIK infusion, or the combination of IABP plus GIK were used. The directed GIK application into the aortic root was carried out by electronic triggering during the diastolic augmentation via a precoronary catheter. In the ischemic and in the non-ischemic myocardium of the left ventricle, ATP, creatine phosphate, and lactate were determined. Electronmicroscopical studies were carried out qualitatively as well as quantitatively. The isolated use of IABP suggested no protection of the energy-rich phosphates. The most significant morphological changes were found when exclusively the coronary ligature was applied and when only IABP was used, respectively. The best protective effect was achieved by our technique of the triggered GIK infusion via the precoronary catheter in combination with IABP. The ATP value (n mol/mg w.w.) in the ischemic area was 3.06 and in the non-ischemic one 4.96 in comparison to 1.96 and 3.99, respectively, in the control group. The creatine phosphate (n mol/mg w.w.) was 4.18 in the ischemic and 9.38 in the non-ischemic area in contrast to 2.36 and 6.99, respectively, in the control group. The technique of the triggered drug supply in combination with IABP offers the following advantages: --additive summation of IABP and substrate supply directed to the myocardium --high drug concentration in the myocardium --smaller drug load of the whole organism --clinical use of instable substances.

Animals↗
PubMed1982

An automatic image analysis of megakaryocytes in fetal liver and adult bone marrow.

The size distribution of megakaryocytes in fetal liver and adult bone marrow was measured with an image processing system AMPA. In the liver, the size of the mature megakaryocytes increased gradually with fetal age. On the 18th fetal day the size of cells became nearly the same as that in the liver of newborn rats. However, the megakaryocytes in the bone marrow had a significantly wider size distribution than those in the liver. These results point to some features of the differences of megakaryocytopoiesis between fetal liver and bone marrows after birth.

Animals↗
PubMed1981

[Gamma globulin as a prophylactic measure in an outbreak of hepatitis A in an institution for mentally retarded children (author's transl)].

An outbreak of hepatitis A was observed in an institution for mentally handicapped children. Within 2 months 21 cases occurred in 4 out of 7 groups. By means of gamma-globulin administration and measures of general hygiene, the outbreak, although not immediately stopped, was brought under control. The number of overt cases was reduced and further transmission to 3 other groups was prevented. The detection of IgM antibodies to hepatitis A virus proved to be very suitable for diagnostic purposes. Subsequently it turned out that the gamma-globulin used had a very low titre in comparison with other preparations. Recommendations are given to prevent similar outbreaks in the future.

Antibody Formation↗