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Biomedical subjects

H Franke

Publications and source records attributed to H Franke.

At least 55 records · Page 3Linked to original sources
PubMed1995

Influence of chronic alcohol treatment on the GFAP-immunoreactivity in astrocytes of the hippocampus in rats.

The influence of long term application of 5% (v/v) ethanol over a period of 36 weeks and 10% (v/v) ethanol over a period of 4,12 and 36 weeks to Wistar rats was investigated. The qualitative alterations of astrocytes and quantitative changes of glial fibrillary acidic protein-immunoreactivity (GFAP-IR) in selected regions of the dorsal hippocampus were examined, using anti-GFAP and the avidin-biotin immunoperoxidase technique. After prolonged (36 weeks) consumption of 5% (v/v) ethanol insignificant alterations were observed. The administration of 10% (v/v) ethanol over 4 and 12 weeks led to an increase of the total GFAP-IR in the examined brain regions. Hypertrophy of the cell bodies and cytoplasmic processes were seen. After 36 weeks decreased total GFAP-IR was measured in all examined brain regions. Cell bodies and fibrillary processes stained less heavily, the number and length of the fibrillary processes decreased and the number of astrocytes in certain hippocampal regions (e.g. in stratum moleculare of the dentate gyrus) appeared reduced. The results show that exposition to ethanol led to the appearance of different astrocytic phenotypes, depending on the concentration and duration of ethanol application, on the age of animals and on hippocampal regions. It is suggested that GFAP can be used as a specific marker for ethanol-induced alterations of astrocytes.

Animals↗
PubMed1995

The effect of continuous G-CSF application in human cyclic neutropenia: a model analysis.

Human cyclic neutropenia (CN) is a rare haematological disorder characterized by oscillations of blood neutrophils at subnormal levels with a stable period of approximately 21 d. During the phase of severe neutropenia (neutrophils < 250 cells/microliters), which last 4-10 d, the patients are endangered by serious infections. Several authors report that continuous G-CSF application can elevate the blood neutrophils to such a level that the risk of infections is significantly reduced. Although the characteristic cycles are not eliminated by G-CSF, the period of the oscillations is shortened to 12-14 d. Based on a previously proposed computer-simulation model of human CN, the effects of continuous G-CSF application on CN are studied. It is shown how the known different cell-kinetic effects of G-CSF on granulopoiesis explain the clinical data in CN. The reduced length of the cycles emerges as a result of the transit time reduction of the post-mitotic granulopoietic cells by G-CSF. The measured increase of the neutrophil maxima is reproduced by the additional mitoses of the immature granulopoietic bone marrow cells induced by G-CSF. The slight elevation of the neutrophil nadirs can be attributed to a weak effect of G-CSF on the assumed underlying defect in CN (an abnormally small variance of the granulopoietic bone-marrow transit time).

Cell Cycle↗
PubMed1995

[Laparoscopic sigmoid resection].

Laparoscopic colorectal surgery not only presupposes knowledge in conventional surgery of the large bowel but also requires extensive experience in laparoscopic techniques. Furthermore every individual of the operating team should have suitable experience to guarantee effective co-operation. The presented study reports on 41 laparoscopic resections of sigmoid colon and upper rectum. The operations were carried out on 31 patients with benign and 10 patients with malignant diseases. In 1 case we had to change to an open procedure. Postoperative complications were seen in 10 patients, one of whom died (secondary haemorrhage 2; anastomotic leakage 1, Douglas haematoma 1, inflammation of the drainage tract 6). Preoperative management, intraoperative procedures and postoperative results are described and discussed.

Adult↗
PubMed1994

Zonal differences in lipoprotein formation in the thioacetamide-induced micronodular-cirrhotic rat liver.

The aim of the studies was to answer the question to what extent thioacetamide-induced structural alterations of hepatic architecture leading to fibrosis and micronodular pseudolobuli affect the formation of very low density lipoproteins and the zonation of lipoprotein metabolism observed in normal and acutely injured livers. Therefore, the number of the VLDL particles/Golgi complex and the relative specific volume of Golgi complexes as well as the number and relative specific volume of VLDL-filled vesicles was determined in lobular and nodular zones of normal and the micronodular-cirrhotic livers, respectively. The perinodular and centrinodular regions were morphometrically analysed in nodules with diameters between 0.3 and 0.5 mm. -Generally, in thioacetamide-induced micronodular liver cirrhosis a zonality was observed with respect to the amount of VLDL particles as well as the number and volume of organelles involved in the formation and secretion of hepatic lipoproteins. However, the number of VLDL particles/Golgi complex was significantly reduced to 52% in the centrinodular and to 71% in the perinodular region of cirrhotic livers when compared with the corresponding periportal and perivenous area, respectively. Furthermore, the relative specific volume of the Golgi complexes markedly increased in the perinodular region, thus abolishing the zonal difference observed in the controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

[Isolation and characterization of hepatocytes from chronic cholestatic damage to rat livers after bile duct ligation].

The aim of these investigations was the isolation and characterisation of hepatocytes from chronic injured rat livers after bile duct ligation. In three months old female Uje:WIST rats the distal common bile duct was double ligated. 14 days after the ligation 80% of the rats survived. The content of hepatic OH-prolin was increased in relation to shamoperated control animals. The histological examination showed a marked fibrous and oedematous spreading of the portal tract as well as an extensive bile duct proliferation after 14 days. A correlation between OH-prolin content of the liver and index of fibrosis was found. 14 days after ligation the hepatocytes were isolated according to Seglen (7). The yield of hepatocytes isolated from the liver of cholestatic rats and from control animals was on average 4 x 10(8) cells with a viability of 80%. Ultrastructural the most hepatocytes showed intact organells without injury. We can conclude, that it is possible to isolate hepatocytes from chronic cholestatic rat livers with a good yield and viability as well as with an intact ultrastructure. These cells are suitable for additional metabolic investigations.

Animals↗
PubMed1993

Quantification of the cell kinetic effects of G-CSF using a model of human granulopoiesis.

Using a mathematical model of normal human granulopoiesis, the most important influences of granulocyte colony-stimulating factor (G-CSF) on the regulation of white cell production can be quantified. G-CSF increases the blood neutrophils via three effects: reduction of the transit time of the postmitotic granulopoietic bone marrow cells; additional mitoses of the early granulopoietic bone marrow cells; and possibly demargination. The application of G-CSF in vivo results in a summation of the single effects. For a G-CSF application of 5 days at a daily dose of 10 micrograms/kg, the reduction of postmitotic bone marrow transit time from 6 days to 1.5 days together with demargination with a rate of 10% per hour explains the initial increase of the blood neutrophils until day 1. Both effects fail to explain the sustained increase thereafter. Enhanced amplification of the early granulopoietic bone marrow cells is also necessary to reproduce the sustained increase. Depending on the individual clinical data, approximately 5 additional mitoses occur, evenly distributed to the myeloblasts, promyelocytes and myelocytes. If the above three effects of G-CSF are assumed, the model predicts bone marrow data in accordance with clinical observations.

Bone Marrow Cells↗
PubMed1992

The visceral yolk sac--an important site of synthesis and secretion of apolipoprotein B containing lipoproteins in the feto-placental unit of the rat.

Rat fetuses exhibit a high serum LDL concentration at term. Delivery caused a marked decrease of the LDL apolipoprotein (apo) B concentration independent of whether this occurred on days 21, 22 or 23 of gestation. The interruption of the yolk sac circulation by a ligature in situ for 6 h led to the same alterations of the LDL-apo B concentration as Caesarean section. Immunoelectronmicroscopic studies provided evidence that the epithelial cells of the visceral yolk sac exhibited electron dense LDL-sized and apo B containing particles which were localized over the compartments of the Golgi complexes, endoplasmatic reticulum, secretory vesicles and intercellular spaces, but not over the cell nuclei, mitochondria or lysosomes. ApoB containing LDL-sized particles could be obtained by ultracentrifugation from the disrupted material of the microsomal fraction of yolk sac homogenates. Isolated segments of the yolk sac membranes were capable to secrete apoB containing lipoproteins floating in the d less than 1.020 g/ml as well as in the d = 1.020-1.064 g/ml fraction with a 10-fold higher amount of apoB in the higher density class. Incorporation experiments with [35S] methionine gave evidence that these lipoproteins were at least partially provided with newly synthesized apoB predominantly found in the LDL fraction. The size of the negatively stained particles in the d = 1.020-1.064 g/ml fraction secreted from yolk sac segments corresponded to that of LDL from fetal rat serum. In contrast their acylglycerol content was significantly higher, whereas the percentage contribution of total cholesterol and protein was markedly reduced in comparison with serum LDL of the fetus. In summary, biochemical and ultrastructural studies provide clear cut evidence that the rat yolk sac is able to synthesize and to deliver apo B containing lipoproteins in the density ranges of VLDL, IDL and particular of LDL thus contributing to the supply of serum lipoproteins in the rat fetus. By recalculation of recent tracer kinetic data (Plonné et al. (1990) J. Lipid Res. 31, 747) using a mathematical step function model it was possible to assess the contribution of the rat yolk sac to the LDL influx into the fetal serum.

Animals↗
PubMed1992

Synthesis, secretion and immunoelectron microscopic demonstration of apolipoprotein B-containing lipoprotein particles in the visceral rat yolk sac.

Electron microscopic investigations on the involvement of the fetal membranes of the rat (visceral yolk sac) in the lipid metabolism revealed the occurrence of lipoprotein-sized particles located in cisternal Golgi stacks, Golgi vesicles and secretory vesicles of the cells of the visceral yolk sac epithelium as well as in distended areas of the intercellular space between adjacent epithelial cells. Application of the protein A-gold technique with specific anti-apoB antiserum resulted in a specific location of immunogold both over the different compartments of the lipoprotein pathway (RER, Golgi complex, secretory vesicles) as well as over the distended intercellular spaces, thus confirming these particles to be lipoproteins in nature. Isolated visceral epithelial cells prepared by a tryptic digestion method exhibited some ultrastructural alterations, such as a loss of apical brush border, a change from columnar to spherical cell shape, a decrease in phagolysosomes, but an increase in autophagosomal structures after 6 h incubation at a vitality rate of at least 85%. Within this period the epithelial cells secreted measurable amounts of apoB-containing lipoproteins into the medium floating in the density classes d less than 1.006 g/ml, d = 1.006-1.020 g/ml and d = 1.020-1.064 g/ml. The production of the lipoproteins was partly inhibited by cycloheximide indicating the secretion of particles with performed as well as newly synthesized apoB. Negative staining of the particles revealed an average diameter of 34 nm of VLDL, 31 nm of IDL and 24 nm of LDL. In summary, our studies demonstrate that in the feto-placental unit of the rat the fetal membranes are capable of synthesizing and secreting lipoproteins. The cells of the visceral yolk sac epithelium were shown to be the producers of apoB-containing particles.

Animals↗
PubMed1992

Quantitative studies on fatty acid metabolism in isolated parenchymal cells from normal and cirrhotic livers in rats.

Parenchymal cells isolated from normal and thioacetamide-induced micronodular cirrhotic rat livers were used to evaluate changes in hepatocellular fatty acid (FA) metabolism in cirrhosis. Exogenous free FA (FFA) are rapidly taken up by hepatocytes obtained either from normal or cirrhotic livers. They are predominantly esterified to triglycerides and accumulate intracytoplasmatically as lipid droplets with increasing cellular FFA uptake. In the parenchymal cells of cirrhotic livers, however, the following changes were observed when compared with controls: (i) decreased cellular output of esterified FA derived both from exogenous sources and from de novo FA synthesis; (ii) increased total ketone body production, mainly as beta-hydroxybutyrate; (iii) decreased cholesterol synthesis; and (iv) enhanced incorporation of newly synthesized FA into phospholipids in spite of an unaffected rate of FA synthesis. In summary, the data provide evidence for intrinsic alterations in the lipid metabolism in the parenchymal cells of cirrhotic livers which are preserved in the isolated hepatocytes under optimum incubation conditions for oxygen and substrate supply.

3-Hydroxybutyric Acid↗
PubMed1992

[Urologic characteristics of 7 patients over 100 years of age].

In the last few decades the old old have increased continuously in numbers. Diseases of the genitourinary organs are a frequent part of the multiple morbidity we are familiar with in such patients. In the 9th decade of life the renal parenchyma is reduced by 30-50%. The decreased glomerular filtration combined with tubular insufficiency leads to disturbances of the electrolyte, water and acid-base balance. In contrast to these involutionary changes in the kidneys, the prostate increases in size owing to varying degrees of hyperplasia, and the incidence of malignant growth increases progressively. A total of 575 patients over the age of 100 years were observed at the Medical Policlinic of Würzburg University, and 7 of these who had pronounced urological disorders are described in detail. The variations in the ageing process are considerable. Urological illnesses in the course of the multiple morbidity usual in this group have a particularly unfavourable influence in the terminal phase of these old old patients.

Aged↗
PubMed1991

Biochemical and morphological studies on perivenous and periportal liver parenchymal cells from female rats isolated by digitonin-collagenase method.

Periportal (pp) or perivenous (pv) liver parenchymal cells from female adult Uje: WIST rats were isolated after retro- or antegrade digitonin infusion followed by collagenase perfusion in the opposite direction. The morphological results revealed a distinct acinar-related destruction of the pv- or pp-zone by digitonin. The remaining cells of the respective other zone showed a good structural maintenance. After subsequent conventional collagenase perfusion the yield, viability and structural integrity of the isolated hepatocytes were high. The zonal cell separation was indicated by significant differences in the pp marker glucose-6-phosphatase and the pv marker glutamine synthetase found in the isolated pp or pv cell populations. Under our experimental conditions including the use of female rats, the alanine aminotransferase and glutamate dehydrogenase as well as ethylmorphine N-demethylase and ethoxycoumarin O-deethylase activities were evenly distributed in both preparations. Under stimulating conditions the capacity for urea synthesis was similar in both pv and pp cells.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1991

[Microsomal phospholipid pattern and liver ultrastructure of aging rats following treatment with essential phospholipids].

The treatment of aging rats with 100 or 300 mg/kg "essential" phospholipids (EPL) for 10 weeks significantly changed the microsomal concentration of phosphatidyl serine plus phosphatidyl inositol. The most marked alterations of the phospholipid fatty acid pattern predominantly observed with unsaturated fatty acids were detectable even 7 days after cessation of EPL application. Ultrastructurally, an enrichment in the hepatocytes with rough endoplasmic reticulum was visible which was more prominent in acinus zone 3. The changes after EPL administration are regarded as the expression of an increased membrane fluidity.

Aging↗
PubMed1990

Biochemical and ultrastructural studies on the effect of verapamil on formation and secretion of lipoproteins in rat hepatocyte suspensions.

The effect of the calcium channel blocker verapamil on structure, formation and secretion of very-low-density lipoproteins (VLDL) from rat hepatocytes in suspension was examined. After 30 min incubation at a verapamil dose of 200 microM neither free fatty acid (FFA) uptake nor triglyceride (TG) and phospholipid (PL) secretion into the incubation medium were significantly changed. After 90 min incubation the TG secretion was inhibited by about 60%, whereas the PL output was only insignificantly lowered, indicating the secretion of abnormally composed lipoprotein particles. Morphologically, after 30 min incubation the hepatocytes had lost their microvillous border and exhibited a 2-3-fold increase in volume density and average size of the lysosomes. In the Golgi-containing regions an accumulation of smooth-surfaced microvesicles was regularly evident. The configuration of the Golgi complexes was normal. After 90 min incubation the lysosomes showed a further significant elevation in volume and size. The Golgi complexes exhibited only minor changes, but their content in VLDL particles was reduced per microns 2 Golgi complex by about 75%. Commonly, the VLDL were larger and more heterogenous in size. The diameter of those VLDL secreted into the incubation medium ranged from 31 to 84 nm, thus surpassing the control values by 2-3 times. The secretion of large-sized VLDL was regularly associated with the intracytoplasmic appearance of dilated smooth-surfaced vesicles filled with size-modified VLDL. These vesicles were concentrated within Golgi-containing areas from where they were widely dispersed towards the cell periphery.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Substructural alterations of liver parenchymal cells induced by xenobiotics.

Xenobiotic-induced basic ultrastructural reactions of liver parenchymal cells as visualized with the basic method in ultrastructural research, the transmission electron microscopy, are described. There exists no "average hepatocyte", but even the normal liver is composed of a heterogeneous population of parenchymal cells revealing distinct ultrastructural and functional differences according to the intra-acinar location, circadian rhythms or metabolic and physiologic conditions. This liver cell heterogeneity is, as a rule, very much increased after acute or chronic exposure of the liver to any xenobiotic compound. Although most electron microscopic techniques are laborious and time consuming, electron microscopic research will play a growing role in analysing the response of the hepatocytes to drugs or other newly developed chemicals. There is no doubt that new methods and instrumental improvements will enable us to visualize more and more the primary site of action of any xenobiotic and the underlying molecular mechanisms in the hepatocytes followed by a sequence of events which lead to the manifestation of a complex reaction pattern composed of adaptation, injury, degeneration and reparation of the liver.

Animals↗
PubMed1990

Age-related changes in the cell kinetics of rat foot epidermis.

The durations of the cell cycle and its component phases have been determined for the basal layer of the epidermis of the skin from the upper surface of the hind foot of the rat using single pulse [3H]-thymidine labelling and the percent labelled mitosis (PLM) technique. Rats of three age groups were used, namely 7, 14 and 52 weeks. The duration of DNA synthesis (Ts) and the G2 plus M phase (TG2 + M) were comparable in 7-week and 52-week-old rats (P greater than 0.1). The major difference between 7-week and 52-week-old rats was in the duration of the G1 phase (TG1). In 7-week-old rats TG1 was 15.0 +/- 0.8 h and in 52-week-old rats TG1 was 31.2 +/- 3.5 h. A consequence of this variation was that the overall duration of the cell cycle was longer in 52-week-old rats (53.9 +/- 5.3 h) than in 7-week-old rats (30.1 +/- 1.3 h). Difficulties were found in fitting a simple curve to the PLM data for 14-week-old rats. This suggests that the proliferative cell population of the epidermis of rats of this age group may be heterogeneous. A satisfactory fit to the data was obtained using a computer model which assumed that the proliferative population of the epidermis of 14-week-old rats was a mixture of cells with cell cycle parameters the same as those of the 7-week and the 52-week-old rats. These two sub-populations of relatively slowly and rapidly proliferating cells were present in the ratio of 2:1.

Aging↗
PubMed1990

The synthesis of glycosaminoglycans in isolated hepatocytes during experimental liver fibrogenesis.

During human and experimental liver fibrogenesis, the pattern of glycosaminoglycans in fibrotic liver matrix is greatly changed by severalfold increases of hyaluronic acid, chondroitin sulfate, and dermatan sulfate, respectively. The present study aimed to determine whether hepatocytes take part during fibrogenesis in the alteration of the glycosaminoglycan profile in liver matrix. Rats received thioacetamide orally for 2 and 10 weeks, respectively. After 10 weeks a typical micronodular cirrhosis had developed. Hepatocytes isolated at these time points were characterized by light and electron microscopy and incubated for up to 4 h in suspension cultures in [35S]-sulfate and [3H]-glucosamine containing medium to study the synthesis and intra-/extracellular distribution of total and specific types of glycosaminoglycans. A biphasic change of glycosaminoglycan synthesis in hepatocytes was found. After 2 weeks of TAA-treatment parenchymal cells synthesized about 25% more labeled glycosaminoglycans than control liver cells, but at 10 weeks the synthesis was reduced by more than 40%. Thus, between 2 and 10 weeks of TAA-treatment hepatocellular glycosaminoglycan synthesis decreased by more than 50%. The major portion of newly synthesized glycosaminoglycans was nitrous acid labile and, hence, identified as heparan sulfate. Its fractional synthesis decreased from 0.90 in control cells to 0.84 (2 weeks TAA) and 0.76 (10 weeks TAA), respectively. Thus, the absolute synthesis of heparan sulfate was reduced by 50% in hepatocytes from cirrhosis liver. Eighty to 90% of labeled glycosaminoglycans remained cell-associated. Hyaluronic acid was detected neither in normal hepatocytes nor in hepatocytes from injured liver. We conclude from these data that parenchymal liver cells will not contribute actively to the accumulation of galactosaminoglycans (chondroitin sulfate, dermatan sulfate) and hyaluronic acid in the extracellular matrix during fibrogenesis. The diminished rate of synthesis of heparan sulfate in hepatocytes from cirrhotic liver might explain its fractional decrease in cirrhotic liver matrix.

Animals↗