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Biomedical subjects

R Gottlob

Publications and source records attributed to R Gottlob.

At least 19 recordsLinked to original sources
PubMed1985

Flat preparations of ocular structures.

We employ a technique which has been used for in vitro studies of the vascular endothelium for obtaining flat preparations of different ocular structures such as corneal endothelium, epithelium of cornea, iris, ciliary body, lens and retinal pigment epithelium. The described method is relatively simple and allows evaluation of the overall state of these cellular sheets. After staining of the preparations with silver nitrate, we found intercellular lines to be present in all specimens studied except in the outer layers of the corneal epithelium. This method could be useful for in vitro studies of different pathological conditions of ocular tissues, both in animal models and in enucleated human eyes.

Animals↗
PubMed1985

Increased serum triacylglycerol and cholesterol binding reserve in acute uremic rats.

In acute uremic rats (24 h after bilateral nephrectomy, serum urea 280-300 mg/dl) the interface tension of the serum is significantly reduced. Serum levels of triacylglycerol are significantly elevated in uremia, whereas cholesterol levels do not show a significant alteration. The in vitro serum binding reserve for both, triacylglycerol and cholesterol is considerably enhanced. These results let suppose the presence of tenside-like substances in uremic serum which may be involved in disturbed triacylglycerol transport from the serum to the tissues and in development of uremic hypertriglyceridemia.

Acute Disease↗
PubMed1985

Arteriovenous flow reversal, experimental investigations. I. Complete flow reversal of the small intestine and of the rear extremity of the dog.

Segments of the small intestine and hind extremities of dogs were perfused under the condition of complete arterio-venous flow reversal (AVFR). In the intestinal segments, the peripheral resistance under AVFR conditions was 4.4 times higher than under orthograde perfusion. Petechiae and hemorhagic infarction were observed. The average flow resistance of the hind extremities was 2.4 times higher than the resistance in control extremities. The pO2 and the O2 saturation in the blood, outflowing from the AVFR extremity was lower than in the control extremity, however, the pO2 was higher. The oxygen consumption was somewhat lower than in the control extremity. It is concluded that by complete AVFR an extremity may be supplied sufficiently with oxygen at least temporarily.

Animals↗
PubMed1985

Arteriovenous flow reversal, experimental investigations. II. Hemodynamic and blood gas analyses in incomplete arteriovenous flow reversal in hind extremities of dogs.

2 types of incomplete arteriovenous flow reversal were tested. When the major arteries were patent, 20% of the blood shunted into a peripheral vein was drained via the arteries whereas 80% was drained via the veins of the leg. If the pressure in the arteries was raised, the flow through the arteries was stopped when the outflow pressure reached 25% of the systemic blood pressure. Under these conditions a moderate oxygen consumption of the peripheral tissues was still observed. When the major arteries and their branches were obstructed by the injection of collagen flocculi the oxygen supply to the tissues was again reduced but not completely abolished. It is concluded that the AVFR procedure may be helpful in avoiding peripheral gangrene in very severe cases of arterial disease. In the first paper of this series (Gottlob and Kunlin, 1985) the hemodynamics of complete arteriovenous flow reversal (AVFR) were studied. In the present communication experiments with incomplete AVFR will be reported on. The animal models described resemble the clinical condition in so far as incomplete AVFR is established and as in both models the flow through the peripheral arteries was hampered.

Animals↗
PubMed1983

Work in progress: transcatheter embolization with cyanoacrylate and nitrocellulose.

The authors describe a modified form of isobutyl-2-cyanoacrylate (IBCA) which has been mixed with less than or equal to 4% w/w of nitrocellulose. Transcatheter embolization was carried out in rabbits and dogs without complications. The glue was readily injectable without balloon catheters. Because of its delayed polymerization, it was carried into smaller peripheral arterial branches by the bloodstream, resulting in complete organ ablation without development of collateral circulation. Other advantages of the modified compound include improved plasticity, adherence to not only ionic but also dry non-ionic surfaces, and the ability to control the duration of polymerization.

Animals↗
PubMed1983

[New experimental documents on circulatory reversal by arteriovenous fistula in ischemia of the extremities].

The beneficial effects of circulatory reversal by lateral a.-v. fistula was confirmed in 20 hind limbs of dogs made ischaemic by Collagen embolisation. Although not done in the experiments presented here, rupture of the distal venous valves is advisable. The peripheral circulation was studied by measurement of venous pressures and by angiography. Retrograde infusions, with proximal tourniquet, confirmed reversal of flow veins to arteries. Return routes to the heart remain unknown.

Animals↗
PubMed1982

[The intra-arterial infusion. II. Its use in the treatment of septic gangrene].

The local toxicity of Cefazolin was evaluated for the arterial endothelium. 37 patients with septic gangrena were treated by intraarterial infusions of standardized Cefazolin infusions into the arteries of the involved legs. In the average 11.6 infusions were applied for one leg. The bacteriology of the infected gangrenous legs is discussed as well as the sensitivity of antibiotics of the germs found. A progression of the gangrena could be prevented in 78% of the cases, only minor surgical measures, such as borderline amputations or plastic interventions were necessary. No side effects due to the local application of the drug were observed. The intraarterial continuous infusion of broad band antibiotics for septic gangrena is recommended.

Animals↗
PubMed1982

[Intra-arterial infusion. I. Kinetic studies on local blood levels].

In dogs the concentrations of agents infused continuously into arteries were assessed in the local and in the systemic circulation. An equation for the gradient between the local and the systemic circulation indicates that in the steady state the gradient is directly proportional to the total clearance of the infused drug and inversely proportional to the blood flow in the infused artery. Within certain limits the gradient is independent of the infused quantity of the drug. By local infusions of antibiotics, such as cefazolin a considerably higher local concentration can be achieved if the local blood flow is impaired, e.g. by arterial disease. By local infusions of streptokinase an increased local fibrinolysis was observed only when the arterial circulation was considerably reduced. Local intraarterial continuously infusions of pharmacologic agents are especially recommended for patients with arterial disease.

Animals↗
PubMed1982

[Study of principles in pathogenesis and therapy of fat embolism. IV. In vivo studies of drug-induced mobilization of embolized lung fat].

Pluronic F 108 added to serum in a concentration of 1 g/dl proved as the optimal means to increase the fat emulgatory capacity. Similar concentrations were achieved in living rabbits by infusing 4.5 g per kg body weight. In spite of this higher dosage we failed to mobilize 131 J labelled fat, embolized into the lungs of the animals. It is concluded that also in humans there exists no possibility to mobilize fat emboli from the lungs by the application of tensides (non-ionic detergents, lecithin-preparations, bile salts) or of organic solvents (alcohol, ether). All these agents are capable to emulsify fat in vitro, however, only under vigorous shaking.--Because of the side effects of those agents their application on patients, suffering from posttraumatic fat embolism seems not to be justified.

Animals↗
PubMed1981

[An animal experimental model for evaluating endothelial damage caused by various angiographic contrast media (author's transl)].

The endothelial damage caused by X-ray contrast media is tested on "en face preparations" of the rat aorta after silver staining. Hypertonic contrast media cause dehydration of the vessels so that solutions of silver nitrate penetrate into the media during the phase of rehydration whereby medial transverse lines are stained. These artifacts can be avoided by 3 minutes rehydration of the vessels by Ringer solution prior to silver staining. In addition it is recommended to add highly diluted silver nitrate to the fixing media in order to intensify the pattern of the endothelial silver lines. Modern contrast media may cause very little endothelial damage, however, significant differences can be detected when in addition to the evaluation of larger foci damages of single endothelial cells ("brown cells" with sparing of the nuclei and "pseudonuclei") are evaluated as well. No significant differences were found between the endothelial toxicity of meglumin diatrizoate and meglumin iothalamate.

Angiography↗
PubMed1980

[Investigations concerning the mechanism of contrast damage. The significance lipophilia (author's transl)].

The damaging action on vascular endothelia of meglumin iothalamate and of meglumin ioxitalamate was tested on the rat aorta. Ioxitalamate was significantly better tolerated than iothalamate. The octanol-water-partition coefficient of various contrast media was evaluated by assessing the iodine content of the octanol phase after mixing. The coefficients found were about 100 fold lower than the coefficients computed by Levitan and Rapoport. The significance of the octanol-water-partition coefficient for endothelial injuries caused by contrast media is disputed.

Blood Vessels↗
PubMed1980

[Basis examinations for pathogenesis and treatment of fat embolism. III. The interface tension of blood against lipids. B. Their influence by addition of surfactants and the effect on the lipid solubility in vitro].

Various surfactants such as Pluronic L 61, L 64, F 68 and F 108, Tween 80 und Triton WR 1339 as well as bile acids and sodium taurocholate were tested for their capacity to reduce the interface tension against neutral lipids and for their capacity to induce stable emulsions of triglycerides in rabbit sera. No positive correlation was found to exist between the interface activity against neutral lipids and the lipid emulsifying capacity of rabbit sera, added with the surfactants. When ether was added to serum, the lipid emulsifying capacity was increased most at concentrations of about 0,0075 g ether per 100 ml serum. This is about 1/10 of the ether concentration, achieved during anesthesia at the stage of tolerance. Pluronic F 108 in non toxic concentrations was the agent increasing the lipid emulsifying capacity of rabbit (and human) sera most efficiently. It proved superior also to ethanol and ether and appears to be the most suitable agent for mobilization of embolized fat in lung vessels.

Animals↗
PubMed1979

[Basic studies on the pathogenesis and treatment of fat embolism. I. Fracture mechanism and fat embolism].

We examined the amount of fat that can be forced into the circulation by compression of femora and of heads of the tibia in the very moment of injury. By fractures of diaphyses no considerable reduction of the intraosseous space was achieved and no fat was expelled through the foramina nutritia before the hard cortical bone was splintered. However, considerable amounts of fat were expelled into veins, when the epiphyses of the femora or when the head of the tibia was compressed from medially and from laterally. Even by a purely manual compression some fat was forced to leave the spongiosa by the foramina nutritia. This is explained by the higher elasticity of the spongious bone, permitting a marked space reduction by compression even before a fracture sets in. The mechanism resembles the procedure of opacification of veins by contrast media, injected into the bone cavity under pressure. The significance of these findings for the pathogenesis of clinical fat embolism is discussed.

Adult↗