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Biomedical subjects

H David

Publications and source records attributed to H David.

At least 127 records · Page 7Linked to original sources
PubMed1981

[Electron microscopic findings during hypothermic storage. Preservation of the liver. I. (author's transl)].

Porcine livers were preserved by simple hypothermic storage for 6 h using plasma-protein-fraction 5%, albumin 5%, Collins C2, and Ringer-lactate. Electron-microscopic alterations primarily consist of aggregations of nuclear chromatin, marginal chromatin condensation, swelling and destruction of cristae mitochondriales, swelling and degranulation of the endoplasmic reticulum. These signs of cell damage are of varying intensity depending on the different preservation methods. The best condition of hepatocytes on the whole is guaranteed by using Collins C2-solution.

Animals↗
PubMed1981

[Electron microscopic findings during hypothermic storage preservation of the liver. II. (author's transl)].

Porcine livers were preserved by simple hypothermic storage for 6 h using plasma-protein-fraction 5%, albumin 5%, Collins C2, and Ringer-lactate followed by a morphometric evaluation of the electron-microscopic changes. The morphometric parameters reflecting swelling of mitochondriae showed the most pronounced changes and were suited best for reproduction. The best result was achieved by using Collins C2-storage. The endoplasmic reticulum was found to be only slightly swollen in all preservation solutions investigated here, at the same time a degranulation of granular endoplasmic reticulum could be demonstrated. The increase in volume of lysosomes per unit-volume was not significant.

Animals↗
PubMed1981

[Cellular sites of action and effects of drugs. A review (author's transl)].

Due to the fact that they are used consciously to achieve positive effects on diseases in man, drugs occupy a special position among the large number of substances that affect the cellular structure and function. In view of the basic similarity and/or parallelism of the structural composition and of the metabolic processes of healthy and diseased cells, one can expect effects on the diseased cell and side-effects on healthy cells to form a unity. The aim of any therapy should be to keep the distance between the positive effect and the side-effect as great as possible, which should be examined and carefully weighed in each case. An attempt is made in the present review to examine by giving some examples the problems involved in the cellular effects of drugs and to explain their action. New therapeutic effects can be found and put to use by knowing the cellular site of action.

Animals↗
PubMed1981

[Changes of cell organelles in the developmental and aging process of heart and liver].

A systematic comparative investigation into the qualitative and quantitative ultrastructure of rat hearts and livers during postnatal development and ageing shows that there are similar and opposing changes within the hepatocytes and cardiocytes and their components. These processes are represented in male rats from birth up to the age of 27 months. The morphometrical examinations include cytoplasm, lipids, glycogen, mitochondria as well as primary and secondary lysosomes. The development of organs constitutes a dialectical unity of continuous and discontinuous processes within the cells characterized by degenerative as well as regenerative and synthetic processes. This results in transformation of the structural organization of the cells during the whole life.

Aging↗
PubMed1980

Gardner's syndrome with an unusual fibro-osseous lesion of the mandible.

A girl with a family history of Gardner's syndrome presented with an actively growing central lesion of the mandible and localized subcutaneous fibrous hyperplasia which required surgical intervention and bone grafting. The importance of this syndrome is the development of intestinal polyposis which become malignant. The presence of dentofacial stigmata and surface tumors should alert the dentist and physician to the possibility of Gardner's syndrome.

Child↗
PubMed1980

The influence of "hylase" on the ultrastructure of ischaemic heart muscle changes.

A two-hour acute ischaemia of the myocardium was induced in dogs by ligature of the coronary arteries and the effect produced on the qualitative and quantitative ultrastructure of heart muscle cells by infusing "hylase", a hyaluronidase preparation, was examined. The changes in both the central and peripheral ischaemic zones following hylase infusion are more severe than after ischaemia alone. Particularly the mitochondria showed an increased dissolution of the outer membrane. In the case of ischaemia the percentage of mitochondria in the peripheral zone is 29.6%, in the central zone 27.6%; after hylase infusion it is 25.9% in the peripheral zone and 32.3% in the central zone. After hylase infusion, the percentage of sarcoplasm in the central zone rises to 120.7% and to 186.8% in the peripheral zone. In view of the fact that macroscopic, histological and histochemical findings also show negative effects, the infusion of hyaluronidase is not recommended.

Animals↗
PubMed1980

Self-administered intravenous and intramuscular pethidine. A controlled trial in labour.

In a randomised controlled trial of mothers in labour intramuscular pethidine 150 mg, repeated if necessary, was compared with self-administered intravenous pethidine (0.25 mg/kg available at 10-min-intervals). Each mother agreed to have either method of pain relief and could opt for epidural block. The intramuscular group had significantly more pethidine than the intravenous group (mean differences, primipara 29 mg; multipara 16 mg). Ratings by mothers of the pain of 1st, 2nd stage and overall (analogue scores and gradings) were consistently better for the intravenous group although not significantly different. There were no differences in mean Apgar scores between the babies in the groups. In mothers who do not choose epidural block, similar pain relief is afforded by adequate intramuscular pethidine or self-demand intravenous pethidine; however, intravenous self-administration is more efficient since the pain relief is achieved with a lower dose of pethidine.

Adult↗
PubMed1980

Maternal opinion about analgesia for labour. A controlled trial between epidural block and intramuscular pethidine combined with inhalation.

In a randomised controlled trial epidural analgesia with bupivacaine 0.5% (mean dose 112.8 mg) was compared with pethidine (mean dose 200 mg) and inhalational analgesia in primipara (28 and 30 mothers) and multipara (17 and 18 mothers). Mothers who had an uneventful pregnancy and labour and agreed to have either treatment were studied during labour and followed-up at interviews for 5 months after delivery. Epidural block was rated significantly superior in respect of pain relief and comfort, there were no differences between the groups in reports of perineal discomfort. Twice as many primipara required forceps delivery after epidural block. Very few mothers, in each group, reported something missing in their experience of childbirth. Two thirds of each group would use the same method again. Epidural block can therefore be recommended to uncommitted mothers as a satisfying and effective method of pain relief for labour.

Adult↗
PubMed1980

Morphometric analysis of myocardial mitochondria in rats during adaptation to exercise.

Comparative morphometric studies of the mitochondria of muscle cells and of interstitial cells of rat hearts were carried out in order to obtain more information about changes in mitochondrial parameters during adaptation of the myocardium to physical training of different durations (45, 180, 360 hours of swimming) and intensities. On the basis of the results the authors conclude that the mitochondrial biogenesis of heart muscle cells occurs in dependence on the intensity of training at two morphometrically different stages. Some parameters of the mitochondria of the interstitial cells reacted in a manner similar to that of the muscle cells, but opposite reactions were also observed. The biogenesis of mitochondria and the absence of a decrease in the mitochondria/myofibrils ratio in muscle cells may be regarded as an improvement in cell metabolism in the training-induced hypertrophy of the rat heart.

Adaptation, Physiological↗
PubMed1980

[The important of lysosomes in myocardial damages, particularly in cases of ischemia (author's transl)].

Secondary lysosomes, such as lipofuscin, are found in considerable numbers in myocardial cells not only with growing age but at any stage of life after intoxications or as a result of congenital heart defects. In addition, lysosomal enzymes are also localized at the membranes of the sarcoplasmic reticulum and at the Golgi vesicles. During ischemia, these enzymes are being detached from the membranes. This, however, happens at a time when the cell has already been damaged irreversibly. Until now, no outflow of lysosomal enzymes from these cells with a following damage of so far unchanged cells has been observed and seems unlikely to happen in view of present-day research results. The primary event and the decisive factor of an ischemic myocardial damage are the ATP reduction which starts within several minutes and the mitochondrial changes connected with it which induce among other things the structural and functional membrane changes, too.

Animals↗
PubMed1980

[Methodological problems and results of the volume and surface determination of rat liver cells during postnatal development].

During the postnatal development of the liver cells until the 6th month of life, their volume increases to 199% of birth value, whereas the nuclear volume increases to 133%. From the 2nd month onwards, values are reached which correspond essentially to those of adult livers. In order to determine the surface it does not suffice to assume a spheroid to get real values. In addition, the number and size of the microvilli in the areas of the sinusoidal cellular surface and that one near the biliary canaliculi have to be determined. Taking into consideration the assessment of the microvilli the cellular surface increases at birth to 116.4% and in the 6th month to 124.3% of the smooth surface. These morphological findings - development of microvilli on the sinusoidal zone of the plasma membrane (6th month: 2,170) and the one near the biliary canaliculi (6th month: 340.2) - are closely connected with the functional behaviour of those plasma membrane areas.

Animals↗
PubMed1980

[Ultrastructural-morphometric studies on the rat liver in the postnatal period. 1. Changes in the extrahepatocyte volume, the hepatocyte nuclei the cytoplasm and and the nucleus-cytoplasm ratio].

Quantitative changes in the volume densities of extrahepatocyte spaces, nuclei of hepatocytes, cytoplasm and of the nucleus-cytoplasm-ratio were studied in male Wistar-rats aged 0 (birth), 1, 2, 3, 4, 5, 6, 7, 14, 21, 28 days and 2, 3, 4, 5 and 6 months. The ratio of hepatocyte/nonhepatocyte fractions is 40.3 : 59.7 at birth and it increases to 86.6 : 13.4 by the 6th month. We observed 2 phases of proliferations of hepatocytes in the first 4 days, while the single volume of hepatocytes reaches lower levels. After the 4th day the single volume of hepatocytes increases because of the augmentation of volume density of cytoplasm. According to these changes the nucleus-cytoplasm-ratio will be reduced to 0.077 by the 5th month.

Animals↗
PubMed1980

[Ultrastructural-morphometric studies of rat myocardial cells during postnatal development].

The morphometrical alterations of heart muscle cells and their cytoplasm of rats were investigated during the postnatal development. Volume density of muscle cells and interstitium shows approximately constant values. Cell colume of muscle cells increased up to the 6th month, however, maxima and minima were observed during this period. Volume density of mitochondria doupled from the birth the the 6th months. Volume density of myofibrills increased poorly.

Animals↗