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Biomedical subjects

W Meier-Ruge

Publications and source records attributed to W Meier-Ruge.

At least 55 records · Page 3Linked to original sources
PubMed1978

Incorporation, after single and repeated application of radioactive labelled DH-ergot alkaloids in different organs of the cat, with special reference to the brain.

1 h after intravenous administration, 3H-DH-ergot alkaloids showed maximal uptake in the range of 10(-5)M in various visceral organs, and of 10(-7)M in most parts of the CNS of the cat. The clearance function in both groups of tissues was logarithmical linear, the slope of the straight line for the parts of the CNS being considerably flatter. Repeated administration of these drugs demonstrated a higher retention in the CNS than in the other organs. The single-dose level in the CNS is reinforced and, in contrast to liver and lung, maintained for at least 24 h.

Animals↗
PubMed1978

[Stereological investigation in the cerebral cortex of aging subjects (author's transl)].

Involving cortical regions, capillaries of the human cerebrum of two 19 and 27 years old men, a 69 years old woman and a 72 years old man were stereologically investigated by optical-electronic image-analysis. The cortical capillary net work was demonstrated by the alkaline phosphatase activity. Each cortex region comprised a determination of the stereological parameters diameter, projected area, specific surface area, capillary distances in linear direction of TV-lines and total length per unit cortex volume. A comparison between different cortex regions revealed a good correlation between increased values of the diameter and the projected area, a decreased specific surface area and diminished capillary distances, which entail a shortened distance of oxygen diffusion through the cortical tissue. During aging a diminished capillary surface area, which results from increased values of diameter and projected area is compensated by shortened capillary distances. Presumably an augmented capillary length is due to a condensation of the capillary net per unit cortex tissue. The behaviour of the registered stereological parameters seems to be an accommodation of the capillary net in the human cerebrum to metabolic and circulatory changes during aging.

Adult↗
PubMed1977

Enzyme histochemistry of rat folic acid nephropathy.

One hour after a single i.v. dose of 250 mg/kg folic acid, the straight portion of distal tubules in the outer medulla of rat kidneys showed a distinct reduction in succinate dehydrogenase, NADH2-diaphorase, glutamate dehydrogenase, cytochrome oxydase, Na+/K+-ATPase, and acid phosphatase activity. In contrast, the proximal tubules exhibited only a reduction in glutamate dehydrogenase and alkaline phosphatase activity. At this time the straight portion of the distal tubules, whose enzyme activity had changed, showed partly regressive epithelial changes. 24 hours after folic acid administration an even greater reduction in enzyme activity had occurred in the straight portion of distal tubules; these structures also became dilated. The adjacent collecting tubules and the corresponding proximal tubules were also severely dilated, the proximal tubules showing a loss in enzyme acitivities similar to those observed in the distal tubules. 48 hours after folic acid administration the changes largely resembled those observed after 24 hours, but were more pronounced. At this time a tubular regeneration was observed. 72 hours after folic administration extensive normalization of the histological and histochemical changes had occured. It is postulated that a disturbance of the hairpin counter-current mechanism occurs as a result of a direct, concentration-dependent effect of folic acid on the enzymes of the energy supplying metabolism. A dilation in the region of the loop of Henle and the collecting tubules occurs subsequently.

Acid Phosphatase↗
PubMed1977

The significance of the hairpin counter-current principle in the pathogenesis of toxic kidney lesions. An investigation of the influence of antidiuretic hormone and papaverine on hydroxyquinoline nephropathy of the rat.

The influence of antidiuretic hormone (ADH) and papaverine on hydroxyquinoline-induced nephropathy in rats was tested, using histotopochemistry, enzyme activity measurement and morphometric investigation. Hydroxyquinoline causes a marked increase in renal weight, the development of wedge-shaped foci with severely dilated tubule segments, and a simultaneous reduction in dehydrogenases, alkaline phosphatase, and alpha-naphthyl esterase. Both ADH and papaverine produced a significant inhibition of renal damage. The subjective findings were quantitatively confirmed by measurement of enzyme activity, using the microscope photometer, and by morphometric studies with the Leitz-Classimat (determination on the basis of the alkaline phosphatase reaction) of the surface percentage of brush border in the proximal tubules. A disturbance of the hairpin counter-current system is to be considered as the cause of the renal lesion. This disturbance is caused by hydroxyquinoline-induced impairment of Na+/K+ transport, especially in the thick ascending limb of Henle's loop. Our results show that the hydroxyquinoline nephropathy can be favourably influenced both by stimulation of water re-absorption and possibly also transepithelial Na+ transport (ADH), and by increasing the blood flow of the arteriolae rectae with a resultant lowering of the intratubular urine concentration (papaverine). The dependency of hydroxyquinoline nephropathy on the phylogenetically determined concentration capacity of the kidney, and the effective influencing of the condition by ADH and papaverine indicate the importance of the degree of efficiency of the medullary countercurrent system in the pathogenesis of this renal lesion.

Alkaline Phosphatase↗
PubMed1976

The laser in the Lowry technique for microdissection of freeze-dried tissue slices.

A new technique for tissue microdissection is described. This procedure, using an u.v.-laser micropreparation instrument, overcomes the extremely time-consuming manual preparation. The u.v.-laser micropreparation design allows fast, precise, reproducible and smear-contamination-free tissue microdissection. The preparation of the tissue sample can be programmed by tracing out the area to be sampled with a non-destructive 0.5 mW He-Ne-laser aiming-beam. The tract is stored in a small electronic unit, which then guides the motor-driven stepping stage on the microscope in the actual dissection run with the u.v.-laser. The laser power is adjustable in the range 4 to 40 kW and controlled by a photo diode displayed on an oscilloscope screen. In the tissue slice, prepared according to Lowry, an unlimited number of cells or tissue compartments can be dissected and afterwards weighed. The procedure described offers a broader use of the quantitative microhistochemical techniques of Lowry and of Neuhoff.

Acid Phosphatase↗
PubMed1976

Cell surgery by laser micro-dissection: a preparative method.

A new UV-laser device is introduced as a micro-manipulator and micro-dissection apparatus for experimental cell research. High energy irradiation is produced by a quasi-continuous N2-laser. The laser micro-beam can be focused to a minimal diameter of 0-75 mum. The micro-laser can be used for cutting and, hence, as a micro-surgical instrument at the level of cellular organelles. Cytoplasmic actomyosin fibrils (AM fibrils) from tissue culture cells (RMCD-cells) are isolated from the surrounding ground cytoplasm. It is shown that the contractile proteins are not damaged by the laser dissection method to an extent that would prevent their normal function, e.g. contraction.

Actomyosin↗
PubMed1976

Effect of yttrium 90 on experimental allergic arthritis in rabbits.

Seventeen rabbits were immunized with complete Freund's adjuvant and bovine serum albumin by the method of Dumonde and Glynn (1962), as modified by Cooke and Jasin (1972). Fifteen weeks after allergic arthritis developed in the knee joint, 8 animals were given an injection of 20 muCi yttrium 90 (90Y) into the left joint cavity; 7 were injected with 400 muCi. The animals were sacrificed at 2, 4, 8, 12, and 16 weeks and at 6 and 12 months after the injection. The right knee joint served as control for assessment of untreated allergic arthritis. Morphological control of the severity of the arthritis was provided by sacrificing 2 uninjected animals 13 weeks after immunization.

Animals↗
PubMed1976

The uptake of DH-ergotoxine by different parts of the cat brain.

The distribution pattern of 3H-DH-ergotoxine, labelled by a direct hydration with tritium, was investigated in the cat brain. Apart from the pituitary gland, the brain shows an average DH-ergotoxine concentration of 10(-7) M. A 15% greater incorporation of DH-ergotoxine occurs in the cerebellum than in the cerebrum. In gradient centrifugation studies it is seen that 60% of the incorporated DH-ergotoxine is localized in the synaptosomal fraction. This finding seems to verify the microhistautoradiographic results of this investigation. The observation of a DH-ergotoxine binding in selected structures of the CNS , predominantly the synapses, could explain central nervous activities of DH-ergotoxine.

Animals↗
PubMed1975

The effect of "ouabain" on the ultrastructure of cerebral arterioles and surrounding tissue, studied by a cannulation of a cerebral artery.

A technique for cannulation of a parietal branch of the middle cerebral artery is described by which high but local concentrations of substances can be achieved in cortical vessels. Using this technique it was shown that ouabain, a specific inhibitor of the Na+-K+-ATPase enzyme system, can produce alterations in the blood brain barrier (BBB) permeability as seen by the passage of Evans Blue into cortical tissue. Electron microscopy revealed changes in the endothelium of cerebral arterioles ranging from an increase in the number of vesicles and vacuoles to complete breakdown of cytoplasm and membranes. Swelling of the peri-arteriolar end feet of protoplasmic astroglia and of dendrites was characteristic of tissue surrounding affected arterioles. Swollen fibrous astrocytes, oligodendrocytes and microglia were not seen even in areas of vasogenic edema. These results are discussed in terms of current ideas of the BBB and astroglial function.

Animals↗
PubMed1975

Cerebrovascular ultrastructural alterations after intra-arterial infusions of ouabain, scilla-glycosides, heparin and histamine.

Cardiac glycosides which inhibit Na/K-ATPase (ouabain, scilliroside, scillirosidin) as well as heparin and histamine were infused into a cannulated branch of the middle cerebral artery or by isolated head perfusion in cats and dogs. Ouabain permeating the blood-brain barrier (BBB) caused the same selective swelling of astrocytes and of certain presynaptic elements as after direct application to the brain tissue. The other cellular elements of brain tissue and the vascular endothelium did not react, although the latter was exposed to the highest drug concentrations (about 10-3 M ouabain). By the swelling about one third of the capillaries became more or less constricted accompanied by an increase in endothelial vesiculation and in the number of osmiophilic inclusions in all cells of the vascular wall and of the pericapillary tissue. Osmiophilic material resembling plasma proteins occured in widened intercellular clefts indicating an increased BBB permeability after survival times (40 min). In contrast to the capillaries some terminal vessels are dilated which may correspond to shunt vessels causing an inhomogeneous, even increased cerebral blood flow after ouabain. Scilliroside and scillirosidin cause essentially the same changes as ouabain, but of smaller intensity and extent. In the present study, neither histamine nor heparin caused any structural change of the vessels or brain tissue.

Animals↗
PubMed1975

Histological study of effects of colloidal 90 yttrium on knee joint tissues of rabbits.

The administration of 0-2-0-4 mCi 90 yttrium (90Y) into a normal rabbit knee joint fails to induce medical synovectomy and results in the proliferation of the synovialis. The synovial mesothelium shows early radiation damage but subsequently follows a restitution of the whole. Later (within 4 to 16 weeks) an extensive fibrosis of the stratum synovialis develops, as well as an occlusion and sclerosis of smaller synovial vessels and capillaries. These changes explain the beneficial therapeutic effect of 90Y in a chronic inflammatory joint effusion. After irradiation that joint cartilage shows an increased cellular proliferation of the superficial tangential cells and in the vicinity of the cruciate ligaments small foci of degenerated cartilage are present. The overall pattern of a joint treated with intra-articular 90Y corresponds to the histological pattern encountered regularly in joints of older people. Changes of the cartilage after the 90Y radiation could represent a factor predisposing the treated joint to a subsequent development of osteoarthrosis.

Animals↗