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Biomedical subjects

G Bretschneider

Publications and source records attributed to G Bretschneider.

13 recordsLinked to original sources
PubMed2002

Primary infection, latency, and reactivation of bovine herpesvirus type 5 in the bovine nervous system.

Bovine herpesvirus type 5 (BHV-5) infection in calves causes meningoencephalitis, a fatal disease highly prevalent in South America. To study the pathogenesis of BHV-5 infection in cattle, 12 calves (group 1: acute infection) and 11 calves (group 2: latent infection) were intranasally inoculated with an Argentinean BHV-5 isolate at 10(8) and 10(4.7) tissue culture infective doses, respectively; six calves (control group) were mock infected. At 3 months postinoculation, all of the calves in group 2 and three calves in group 3 were given dexamethasone to reactivate the virus. The animals were euthanatized between days 6 and 17 postinoculation (group 1) and between days 6 and 16 postreactivation (group 2). Seventy-five percent and 91% of animals in groups 1 and 2, respectively, excreted BHV-5 in nasal and ocular discharges. Following dexamethasone administration, 45% of calves shed virus in both types of secretions. Spontaneous virus reactivation and shedding was observed in one calf. Neurologic signs consisting of circling, teeth grinding, ptyalism, jaw chomping, tongue protrusion, and apathy were observed in two animals in group 1 and, during the reactivation period, in four animals in group 2. Macroscopic findings consisted of softening of the cerebral tissue, meningeal hemorrhages and swelling, and edema and hemorrhages of prescapular, retropharyngeal and submandibular lymph nodes. Histologic lesions consisted of meningitis, mononuclear perivascular cuffing, neuronophagia, satellitosis, gliosis, hemorrhage, and necrosis and edema. Lesions in anterior cerebral cortex, medulla, and pons were consistently seen in all the animals of group 1. In the acutely infected animals, lesions in the diencephalon appeared at day 10 postinoculation, whereas in the latently infected calves these lesions were observed as early as at day 6 postreactivation. Latently infected animals developed lesions simultaneously in anterior cortex, medulla, pons, and diencephalon, showing a remarkable difference from the acutely infected group. Trigeminal ganglionitis appeared relatively early in animals of both groups (day 7 postinoculation in group 1 and day 8 postreactivation in group 2).

Animals↗
PubMed1984

[Comparative temperature measurement by thermoprobes and infrared pyrometry in the rewarming of frozen kidneys using short wave generators].

Mini pigs' kidneys were frozen to -20 degrees C after initial hypothermic perfusion and cryopreparation with dimethyl sulphoxide. They were subsequently thawed out with short-wave radiation. During this procedure continuous temperature measurement is only possible using infra-red pyrometry without physical contact. After completion of short-wave irradiation at ca. 4 degrees C the surface and internal temperatures are measured with thermoelements. In comparison with measurement by thermoprobes, infra-red pyrometry proves to be quite practicable, with certain limitations. If a homogeneous distribution of temperature in the organ is assumed; the internal temperature could be calculated from the surface temperature. Also, continuous observation of temperature changes ist possible.

Animals↗
PubMed1982

[Ultrasonic Doppler methods of blood flow studies of the arterial circulation from the aorta up to the kidney parenchyma in animals].

The Doppler method of ultrasonography was used in experimental investigations to examine the circulator behaviour at various points in the arterial system in the retroperitoneum as fast as the kidney in animals with normal circulation. This enabled reproducible Doppler curves to be determined. It remains to be seen to what extent characteristic curve patterns exist for e.g. partial or subtotal vascular occlusion. For the future it will be especially important to determine the flow curves in the cortical region of the renal parenchyma as an area of small and very small vessels, for this can give us important information on the circulation of blood in the individual segments of the kidney.

Animals↗
PubMed1979

[Behavior of the renal perfusion resistance during automatic organ preservation].

It is reported on experimental investigations in the preservation of mini pig kidneys. At first the behaviour during the initial hypothermic gravitation perfusion is examined. From the relation of perfusate outflow to the perfusate inflow the perfusion quotient PQ is calculated. It is a measure for the volume storage developing during the perfusion (tissue oedema?) and significantly correlates with the warm dead time. The behaviour of the renal current resistance during the following machine permanent perfusion was examined with the help of KABI-albumin-solution and Collins-solution with 5% dextran M 40, and Collins-solution with 5% dextran M 75. Here was shown that the increase of the current resistance correlates with the preservation time depending on the PQ of the initial perfusion. The result is a typical behaviour for the individual solutions. We are of the opinion that the judgement of the behaviour of the kidneys during the machine perfusion must be seen in connection with the initial perfusion.

Animals↗
PubMed1978

[Temperature measurements and course in a kidney preservation unit].

It is reported on two models of organ containers in which the course of the temperature was measured and registered on different conditions. The principle of construction used allowed the resignation of a special isolation. The results show that behaviour and course of the temperature in the organ containers meet all requirements.

Kidney↗
PubMed1977

[Experimental coronary stenoses and occlusions].

A constrictor for experimentally inducing stenoses and obstructions of the coronary artery is described. Smallness, good adaptability to every vascular diameter, atraumatic insertion, and slow swelling are its advantages. Within 12 months a coronary artery could be constricted by two thirds. In one third of the cases the lumen was narrowed by more than 75 per cent. Just 50 per cent of the cases showed chronic infarction after coronary obstruction, the other half developed differently marked myocardiac fibrosis. At high-degree narrowing of the arteries, 75 per cent of the cases showed disseminated myocardiac fibrosis. The occlusion of the vessel is caused by constrictor, by fibroplastic alteration of the vascular wall, and by thrombosis. Different degrees of myocardiac ischemia are sequelae of different development of collaterals. The constrictor may be used for studies on the development of collaterals as well as on therapeutic measures in chronic ischemia of the myocardium.

Animals↗
PubMed1975

[Dye-marking and hydrogen clearance in demonstrating acute ischemic myocardial areas].

After acute myocardial infarction (produced by ligation in the dog), the authors marked the borders of infarction with disulphine blue or methylene blue and determined, by means of hydrogen clearance, the blood supply in the centre and at the margin of infarction as well as at different distances from the latter. At the margin of infarction, the value for blood flow amounted to almost 17% of the value measured prior to ligation. Only at a distance of 1 cm. from the visible margin of infarction, 50 to 80% of the initial value were obtained. The extension of the area of infarction beyond the marked visible margin must be considered in surgical interventions.

Animals↗