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Biomedical subjects

F Hammersen

Publications and source records attributed to F Hammersen.

At least 55 records · Page 3Linked to original sources
PubMed1983

Hemodynamic, biochemical and morphological changes in the dextran and D-galactosamine-induced edemas in rats.

Dextran (600 mg/kg i.p.) and D-galactosamine (300 mg/kg s.c.)-induced edemas in the rat have been evaluated and compared on the basis of hemodynamic, biochemical and morphological investigations. The genesis of the edema induced by dextran was quicker (1-3 hr) than that induced by D-galactosamine. The edema index at the levels of the paws was higher in the dextran (10.5 +/- 0.6) than in the D-galactosamine (5.1 +/- 0.4)-induced edema. Furthermore, the dextran-induced edema was associated with marked hypotension and a decrease in the plasma protein levels. Bradycardia, decrease in the cardiac output and the coronary blood flow were observed in both the edemas. Blood flows to the brain, kidneys, lungs, spleen and paws were decreased only in the dextran-induced edema. It was interesting to note that the percentage distribution of the cardiac output in the paws was decreased in the dextran-induced edema only. PGE2 levels were increased, whereas the histamine levels were decreased in the paw-skin in both the edemas. These changes were relatively more marked in the dextran edema. The levels of PGF2 alpha remained unchanged. The above findings have been further supported by our morphological data where relatively more degranulation of the mast cells and that too at a shorter period, was observed in the dextran-induced edema. Different mechanisms for the genesis of these two kinds of edemas have been suggested.

Animals↗
PubMed1982

A paracrystalline inclusion body in normal human vascular endothelial cells.

Peculiar crystalloid containing cytoplasmic inclusions are described for human umbilical vein endothelial cells (EC) which have never been reported for normal human blood vascular EC before. The inclusions are distinctly membrane-bound, their diameters range from 0.4 to 0.8 micron, and they tend to form clusters. In the latter case the corpuscles are pressed together very tightly and their membranes are often cross-connected by a thin electron dense thread traversing the intermembrane space in a very regular zigzag fashion. The contents of these inclusions vary from finely granular and homogeneous to more or less coarsely vesicular and inhomogeneous, finally culminating in the appearance of stacks of regularly arrayed electron-dense bands. These crystalloids vary in size and either one or more of them occur within the same corpuscle, thereby occupying different amounts of its volume. The various contents of these inclusions together with their close proximity and their actual fusion with defective mitochondria already point to a lysosomal and thus an organelloid nature of these structures. This assumption is strongly supported by the demonstration of acid phosphatases in the supernatant of cultures of human umbilical vein EC as well as by the ultrastructural localization of this marker enzyme within these corpuscles. These findings induced us to hypothesize that this crystalloid containing endothelial component appears to be species specific (human) with a distinctive preference for endothelial cells of various origins.

Capillaries↗
PubMed1982

Microcirculatory blood flow, capillary morphology and local oxygen pressure of the hamster amelanotic melanoma A-Mel-3.

Transparent chambers and permanent indwelling catheters were implanted in the dorsal skin flaps of 24 inbred golden Syrian hamsters. After 48 hours, 4 x 10(4) amelanotic melanoma cells (A-Mel-3) were transplanted sc (12 hamsters) in areas exposed for intravital microscopy. A platinum multiwire electrode and techniques for a quantitative analysis of television images were used for measurements of local oxygen pressure (PO2), capillary blood cell velocity, capillary density, and capillary diameter and length, whereas capillary morphology was evaluated by electron microscopy. Compared to the mean local PO2 of the skin flaps of controls (12 hamsters), the mean local PO2 on the tumor surface of melanoma-bearing hamsters decreased with tumor size. Although capillary density of the melanoma was elevated 4 days after tumor transplantation, it decreased significantly until day 12. Of hemodynamic significance were huge platelet conglomerates in short, dilated capillaries. Electron microscopy revealed endothelial hyperplasia, open endothelial junctions, and disintegration of the capillary endothelium. These findings strongly suggest that elevated microvascular resistance, intratumor tissue pressure, and widening of intercapillary distances in the melanoma might significantly diminish the impact of chemotherapeutic treatment.

Animals↗
PubMed1980

The occurrence of paracrystalline mitochondrial inclusions in normal human skeletal muscle.

Two different types of paracrystalline mitochondrial inclusions identical with or very similar to those already described in the literature for a variety of muscle diseases were found in human skeletal muscle biopsies obtained under general anesthesia before ischemia and after various periods of anoxia up to 150 min. As these crystalloids could be observed in seven of 14 healthy subjects and occurred in five of these seven cases either before or only 10 min after onset of ischemia, it is suggested that such mitochondrial inclusions develop not only under the influence of variant noxious stimuli, but may also represent a normal constituent of human skeletal muscle mitochondria.

Adolescent↗
PubMed1979

The fiber composition of the semitendinosus muscle of the rabbit.

The semitendinosus muscle of the rabbit is composed of a homogeneous fiber population. Fiber typing was carried out by means of light and electron microscopy according to which this muscle exhibits structural features that are either characteristic for both "red" and "white" fibers, or that do not allow for any classification according to the A-, B-, C-fiber system. Hence the long-held assumption that the semitendinosus muscle of the rabbit represents a classical paradigm of a "red" muscle should be revised in light of the present results.

Animals↗
PubMed1979

Isolation of H1N1 influenza virus in Munich.

During an outbreak of a mild upper respiratory tract infection in a university children's hospital in Munich, an H1N1 influenza virus was isolated. Serological analysis of the isolate showed that antigenically the virus resembled the USSR/90/77 strain of influenza A virus which has been isolated in many parts of the world during the last two years.

Antigens, Viral↗
PubMed1977

[Idiopathic edema, capillaropathy, pericardial and pleural effusions with high protein content (author's transl)].

Clinical and electron microscopic studies of two female patients are reported who, in addition to the symptoms and signs of idiopathic edema, had pericardial (and pleural) effusions. In one patient pericardiectomy had to be performed, in the other patient pharmacotherapy with spironolactone was effective. In these patients the protein-concentrations of edema fluid (25 and 12 g/l) and pericardial fluid (55-61 and 48 g/l) were relatively high; the distribution space of labelled protein was increased; blood volumes were low-normal or decreased. Electronmicroscopy of the microvasculature showed identical alterations in both cases. In the cutaneous vessels the endothelium developed numerous abnormal cytoplasmic processes and intercellular "gaps". In the capillaries of skeletal muscle our findings indicate an increase in vesicular transport. We suggest the electron microscopic alterations to be the morphologic correlate for the increased transport and extravascular accumulation of protein. Changes as they are described here in humans with idiopathic edema have been documented before in animals with experimental edema.

Adult↗
PubMed1977

Effect of contraction on lymphatic, venous, and tissue electr-lytes and metabolites in rabbit skeletal muscle.

The effect of muscle contraction on lymphatic and plasma [K+], [Na+], [Ca2+], [Mg2+], [Cl-], [Pi], [lactate] ([Lac-]); [creatine] ([Cr]), ideal osmolality (OSM), and [protein] was evaluated in femoral venous blood and lymph specimens sampled from the calf muscles of rabbits before, in the course of, and after contractions. In addition, total [K+], [Na+], [Ca2+], [Mg2+], [Cl-], and [H2O] were analyzed in the muscle tissue. To facilitate lymph sampling both hind limbs were passively flexed and extended, in imitation of natural running movements, by an electrically driven crank. The muscles of one side also performed superimposed rhythmic isotonic contractions. Before contractions, lymphatic [K+], [Na+], [Ca2+], [Mg2+], [Lac-], [Cr], and OSM did not significantly differ from corresponding femoral venous concentrations, [Cl-], and [Pi] were significantly higher, [protein] significantly lower in the lymph than in the plasma. During contractions lymphatic [K+], OSM, [Lac-], and [Pi] were raised significantly more in the lymph compared with the plasma concentrations. [Na+], [Cl-], [Ca2+], and [Mg2+] showed only small changes in the course of contractions and thereafter, and they were altered in a similar way in the lymph and plasma. It was suggested that lymphatic and interstitial concentrations were in equilibrium. Comparing inactive with active muscles, the latter lost K+ but gained Na+, Cl-, and H2O, whereas minimal changes occurred in the [Ca2+] and [Mg2+]. The changes were discussed in connection with the hypothesis that electrolyte shifts might be involved in the activation of the muscular non-proprioceptive interstitial nerve endings which appear to play a role in reflexogenic cardiovascular and respiratory control.

Animals↗
PubMed1976

Studies on the fine structure of invertebrate blood vessels. II. The valves of the lateral sinus of the leech, Hirudo medicinalis L.

The position, structure and function of the valves within the lateral sinus of the medical leech, Hirudo medicinalis, are described on the basis of vital, light- and electron microscopy. In this species the valvular apparatus consists of multiple elongated fir cone-shaped fibrous villi surrounding the orifices of the latero-lateral and latero-dorsal vessel like a tentacular crest. Each villus is covered by a thin sheet of a continuous endothelium. The valves prevent the backflow of hemolymph during systolic contraction of the lateral sinus. The endothelium contains many small mitochondria and polyribosomes in the perinuclear cytoplasm and it develops deep projections into the underlying connective tissue. Each of these consists of a multilayered system of closely interwoven thin endothelial membranes. The endothelium is anchored to its basement membrane by means of a great number of poorly defined hemidesmosomes. The fibrous tissue of the villi consists mainly of a homogeneous vitreous matrix in which few cellular components and very fine filaments are dispersed. Close to the endothelium this matrix appears to be condensed to form a multilayered framework made out of a basement membrane-like material. Though the valves themselves are devoid of muscle cells, those situated at their base and thus belonging to the vascular wall proper, display some specific morphological features: in particular the nuclei of these cells show a distinct fibrous lamina. Moreover, these muscle cells seem to be innervated only by one type of axon, containing both small, lucent synaptic vesicles as well as some of the dense-core variety. These findings are compared with data from earlier works and are discussed in relation to the hemodynamic functions of this valvular apparatus.

Animals↗
PubMed1976

Endothelial contractility - an undecided problem in vascular research.

The rather old conception that endothelial cells possess an autonomous contractile capability has been reevaluated by several suthors during the past ten years on the basis of three different arguments of various validity: (1) After the topical application of inflammatory mediators tmajno et al. regularly found the endothelial nuclei furnished with numerous identations together with many interendothelial "gaps"; Both findings are assumed to be the morphological correlate of an endothelial shortening due to the contraction of the cells. While nuclear indentations seemed to be a rather weak argument to substantiate contractile capabilities, a mechanism other than contraction is outlined for the formation of "gaps"; (2) The second argument in favour of endothelial contractility is the occurrence of cytoplasmic filaments that occasionally form cross striated bundles and/or show a "thick" and "thin" variety. If all these data are assumed to be the morphological evidence for the contractile capability of cells then the conclusion: the more filaments the higher the contractile activity, must be valid. But when compiling those endothelia that are particularly rich in filaments this conclusion does not make sense, because e.g. the endothelium covering the venous valves is crowded with filaments yet an especially high "contractile activity" does not seem very probabble. On the other hand, the supposition that endothelial conttractility is entirely independent of the existence of cytoplasmic filaments leaves the question unanswered what then are the filaments for if not serving mechanical purposes. This line of reasoning is supported by both the localization of the filaments predominantly in those endothelia that have to sustain higher degrees of various mechanical stresses and the fact that filamentous structures significatnly increase in number under the influence of hypertension. (3) The final argument brought forward to substantiate endothelial contractility is the demonstration of actin and tropomyosin in the endothelium of various types of blood vessels that also occur under the influence of hypertension; tbut the significance of these findings as a proof for endothelial contractility is curtailed by the fact that the occurrence of actin alone is not conclusive for any contractile capabilities; Furthermore, a convincing demonstration of myosin in endothelial cells is still lacking and the "thick" filaments are believed to be noncontractile. Hence we suggest that the endothelial filaments together with the myoid proteins do not serve as a means for "contractility" in a true sense but simply act as a design to originate tensile strength.

Animals↗
PubMed1976

[Recent morphologic and experimental results on the normal and impaired function of cutaneous vascular organ].

The objective of this article is to briefly review our present knowledge of the pattern, the functional behaviour and the fine structure of the cutaneous papillary vessels and their alterations under various pathological conditions. The shape of these capillary loops varies within wide ranges dependant on the functional state of the covering epidermis. If the latter is hyperplastic the vessels are elongated, twisted and coiled. In case of epidermal atrophy the capillaries become shorter, decrease in number until their final complete absorption. At the level of the electron microscope the capillary wall clearly shows to consist of 2--3 or more endothelial cells of high electron density encircling an always narrow lumen. Both the inner and outer endothelial surfaces are irregular in outline and the cytoplasm is crowded with filaments of 50--70 A in diameter. In addition it is characterized by the occurrence of a larger number of vacuoles and Weibel-Palade bodies, the latter serving as an excellent marker for endothelial cells to e.g. clearly decide the morphogenesis of certain vascular tumors. Along their apex the capillary loops show a fenestrated endothelium particularly at their adepidermal sites. The basal lamina is multilayered and thereby giving a scroll-like appearance in cross sections. At the ultrastructural level endothelial cells are only provided with a limited repertoire of reactions to noxious stimuli. Among these are: (1) an increase in vesiculation and organelles, (2) the formation of cytoplasmic processes often accompanied by the development of interendothelial "gaps" and (3) alterations - mostly thickenings - of the basement membrane. These different fine structural changes were shown to also occur in various diseases of the skin including it's vascular tumors. In experimental research of the skin microvasculature the most spectacular technique was that of a human skin chamber as originated by Branemark. Thereby most of our older findings as to the functional behavior of the microcirculation in laboratory animals were shown to be valid and hence transferable to humans provided similar experimental approaches were used. Finally the vitalmicroscopy and ultrastructure of tumors (melanoma, hemangiopericytoma and neurilemmoma) transplanted into the hamster cheek pouch are briefly outlined.

Adult↗