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Biomedical subjects

R Scherer

Publications and source records attributed to R Scherer.

At least 91 records · Page 5Linked to original sources
PubMed1984

[Hemodynamic and respiratory changes in operations of the esophagus by unilateral ventilation].

One-lung ventilation offers optimal operating conditions during intrathoracic surgery. Hemodynamic and respiratory changes were measured in 9 patients. Cardiac output was unchanged, arterial pO2 decreased and venous admixture increased markedly. The increase in mean pulmonary artery pressure and pulmonary vascular resistance are signs for hypoxic pulmonary vasoconstriction in the unventilated lung. In spite of an inspiratory oxygen concentration of 66% oxygen availability was decreased by about 20%. Anaesthesia and related procedures should not interfere with pulmonary autoregulation. Complete monitoring is necessary to safely assess oxygenation of the patient.

Carbon Dioxide↗
PubMed1984

Cardio-respiratory changes and prostaglandins during one-lung-anesthesia.

In a clinical study the intraoperative changes in prostaglandin levels and their possible influence on venous admixture during one-lung anesthesia are investigated in 9 patients undergoing abdomino-thoracic resection of a carcinoma of the oesophagus. During one-lung anesthesia PaO2 decreased and Qsp/Qt increased significantly. In 7 of the 9 patients prostaglandin E2 in the arterial blood was significantly above normal level during two-lung- and one-lung ventilation, prostaglandin F2 alpha was below normal values in all patients during two-lung- and one-lung ventilation. The clear prevalence of vasodilating prostaglandin E2 may have reduced the effectiveness of hypoxic pulmonary vasoconstriction during one-lung ventilation.

Anesthesia↗
PubMed1983

Oxygen transport during hemodilution in normoxic and hypoxic dogs treated with verapamil.

In order to determine the possible limitations of acute isovolemic hemodilution in patients taking verapamil, the various factors determining oxygen availability were analyzed in an animal experiment. Twenty-four anaesthetized dogs were subjected to a gradual isovolemic hemodilution. Six dogs received a bolus injection of 0.1 mg kg-1 of verapamil followed by 0.01 mg kg-1 min-1. In 12 dogs, mild hypoxic hypoxia was induced by ventilation with 16-17% oxygen; six of them also received verapamil. Six dogs served as a control group. In the latter, due to an increase in heart rate and stroke volume, oxygen availability in the clinically relevant range of hemodilution between HC 25 and 25% was maintained at 81% of its control value. In normoxic animals treated with verapamil, oxygen availability decreased more rapidly and was below the level of the control group once HC reached 25%. Mild hypoxic hypoxia alone did not reduce oxygen availability as much as its combination with verapamil. Even though the verapamil-induced reduction in oxygen availability was similar during normoxia and hypoxia, the sharp rise in serum lactate at HC levels below 35-30% in the hypoxic verapamil group was a sign of impairment of tissue oxygenation. Hematocrit levels below 35-30% and even moderate hypoxemia should be avoided whenever the cardiovascular response to hemodilution is influenced by verapamil.

Animals↗
PubMed1983

Laser nephelometric determination of glycosaminoglycans--method and application.

Light scattering due to the formation of insoluble complexes between the long-chain quaternary ammonium salt N-cetylpyridinium chloride and glycosaminoglycans was utilized for a relative simple, sensitive and precise determination of total and specific types of glycosaminoglycans by laser nephelometry. The addition of the ammonium salt to solutions of various glycosaminoglycans in 0.03 mol/l NaCl produces a time-dependent increase in light scattering, which reaches a maximum between 14 and 18 h of complex formation, irrespective of the type of glycosaminoglycan studied. Only keratan sulphate does not generate light scattering, and is therefore not detectable by the procedure. The scattering of laser light by certain types of sulphated glycosaminoglycans (e.g. heparan sulphate, heparin) depends more on the degree of sulphation (charge density) than on chain length within a certain range. Optimum light scattering was found at 28 mmol/l N-cetylpyridinium chloride and at a ionic strength around 0.03 mol/l NaCl. The detection limits and linear ranges of the individual glycosaminoglycans were evaluated. For the determination of chondroitin sulphate, laser nephelometry is at least 8 times more sensitive and much more simple than the modified carbazole method (glucuronic acid). The intra-assay and inter-assay coefficients of variation are about 4% and 7%, respectively. Laser nephelometry is much more sensitive than turbidimetry. Complex synthetic mixtures of glycosaminoglycans and biological fluids were accurately differentiated by successive chemical and enzymatic degradation of the respective glycosaminoglycans followed by the measurement of the resulting reduction of laser light scattering. In synovial fluids from non-inflammatory joint diseases, light scattering (units/ml) was about 4.5 times higher than in synovial fluids from inflammatory articular lesions. In both pathologic conditions nearly all of the light scattering can be attributed to hyaluronic acid.

Cetylpyridinium↗
PubMed1983

[Unilateral lung edema following chest injury: an indication for independent artificial respiration].

The successful treatment of a unilateral penetrating stab wound injury of the chest is reported. Following emergency resection of the upper and middle lobe of the right lung acute pulmonary oedema developed in the dependent left lung. Air-tight suture of an additional injury of the right lower lobe was not possible. To avoid formation of a fistula in the right lung, the patient was intubated with a double lumen endobronchial tube and both lungs were ventilated independently. Application of positive-endexspiratory pressure to the oedematous lung improved oxygenation without exposing the right lung to undue inspiratory pressure. The advantages and indications of a double-lumen endobronchial tube in the primary care of unilateral chest injuries are discussed.

Adult↗
PubMed1983

[Assessment of the value of sedation and mobilization in the therapy concept of mechanically ventilated patients].

Continuous improvements in intubation technology have caused a substantial change in the treatment of intubated patients. Whereas, until a few years ago, patients requiring intubation were sedated and treated by muscular relaxation for technical reasons, today sedation is no longer technically indicated. The patient is sedated so that he may be spared the potentially traumatizing psychic experience of machine ventilation. Recent investigations have shown, however, that the emotional strain to which intubated patients are subjected cannot be specifically attributed to artificial ventilation, but rather that it may occur in any severe physical illness. This strain may be eased by a positive relationship between the patient and the ICU staff. Routine sedation of intubated patients thus seems unnecessary. Nevertheless, there are some indisputable medical and psychological arguments in favour of sedation of intubated patients, including insufficiently stabilized fractures, states of restlessness, tetanus, intentional reduction of oxygen consumption, etc. Among the objectives to be achieved by mobilizing intubated patients are the following: restoration of the patient's autonomy, prevention of impaired consciousness, improved oxygenation. A meaningful performance of mobilization under both medical and psychological aspects is also described.

Exercise Therapy↗
PubMed1982

Disturbances of selected plasma proteins in hyperdynamic septic shock.

This study was performed on patients (n = 18) suffering from strictly defined hyperdynamic septic shock. Plasma factors (C-reactive protein, acid alpha 1-glycoprotein, fibrinogen, fibrinopeptide A, fibrinogen-fibrin split products, factor XIII, antithrombin III, complement factors C3 and C4, inter-alpha-trypsin-inhibitor and alpha 2-macroglobulin) measured during hyperdynamic septic shock were highly abnormal. The activation and consumption of clotting, fibrinolytic and complement factors due to system-specific proteinases (such as thrombokinase or plasminogen activators) seemed to be intensified by the nonspecific proteolytic activity of granulocytic proteinases probably released by the action of endotoxins. Possible therapeutic measures to maintain the endogeneous defence mechanism against enhanced proteolysis during septic shock are discussed.

Alpha-Globulins↗
PubMed1981

Demonstration of antiinflammatory activity of fibrinogen and fibrinopeptides in rats.

Carrageenin-induced inflammatory rat paw swelling was significantly inhibited by intraperitoneal injection of rat fibrinogen. Whole-body radioscanning of the rat after intraperitoneal administration of 131I-labeled fibrinogen revealed the accumulation of radiolabeled material in the inflammed rat paw. Resorption studies showed that not more than 4% of the intraperitoneally administered [125I] fibrinogen could be demonstrated in the peripheral blood. Furthermore only 1/3 of this circulating radiolabeled protein was able to take part in clot formation, suggesting that inhibition of edema formation is mediated by fibrinogen-derived split products. This is further supported by the finding that rat fibrinopeptides, released by the action of thrombin, also diminish edema formation both after intracardial and intraperitoneal injection into carrageenin-stimulated rats.

Animals↗
PubMed1981

Kinetics of the acute-phase reaction in rats after tumor transplantation.

Transplantation of Yoshida sarcoma (solid type) and Zajdela ascites hepatoma tumors in rats induces a biphasic change in the concentration of the following five acute-phase proteins: alpha-1-acid glycoprotein; alpha-1-antitrypsin; haptoglobin; hemopexin; and ceruloplasmin. These proteins and other plasma proteins were quantitated by two-dimensional immunoelectrophoresis relative to normal serum concentrations. The elevation of most of these acute-phase proteins was greater in the second phase, during which serum levels increased continuously as the tumor burden increased until the animals died. The increase in haptoglobin concentration during the second phase was much higher in rats bearing Yoshida sarcoma than in rats bearing Zajdela tumors. Rats receiving irradiated tumor cells showed neither tumor growth nor second-phase protein changes. Significant increases in uptake of 3H-amino acids by isolated perfused livers of tumor-bearing rats provided evidence for an increase in the hepatic synthesis rates of the acute-phase proteins. Removal of the solid tumor resulted in a gradual decrease of acute-phase protein concentrations with concomitant increase in serum albumin concentration. These alterations in serum acute-phase proteins during tumor growth and after removal of the tumor may make their use attractive as biological markers of the response of the tumor-bearing animal to its tumor.

Animals↗
PubMed1981

[Apthae: histologic, immunofluorescent and immuno--electron microscopy study of their pathogenesis].

The present study was done to elucidate the pathogenesis of aphthae in recurrent oral ulcers and Behcet's disease. Histologically, early stages of aphthae showed a predominantly neutrophil infiltrate and leukocytoclasia in the vessel walls, as well as extravasates of erythrocytes. In later stages, also histiocytes and lymphocytes appeared. By direct immunofluorescence technique, 30 of 34 patients showed perivascular precipitates of C3 and Clq, eight patients in addition, IgM and IgG. Remarkably, band-like fine granular precipitates of C3 were present in the basement membrane zone. By immunoelectronmicroscopy, C3 was demonstrated in fine subendothelial granules of the vessel walls and of the epithelial basement membrane below the lamina densa. There were no fundamental differences between the aphthae of recurrent oral ulcers and Behcet's disease. Our findings indicate, that an immunecomplex vasculitis is involved in the pathogenesis of aphthosis.

Behcet Syndrome↗
PubMed1980

Biosynthesis of plasma proteins in serum-free medium by primary monolayer culture of rat hepatocytes.

Morphologically intact rat hepatocytes separated by collagenase perfusion were cultured in L-15/fetal calf serum medium to form a monolayer. Thereafter the hepatocytes were grown in serum-free L-15 medium in which they produced and continuously released plasma proteins. The secreted plasma proteins were collected, separated and characterized by crossed immunoelectrophoresis. Most of the newly biosynthesized plasma proteins secreted into the medium during incubation for thirty hours had the same electrophoretic mobility, antigenicity and staining characteristics as their counterparts in rat serum. The addition of tritium labelled amino acid mixture to the culture medium revealed that the release of radioactively labelled plasma proteins into the culture medium was essentially linear during the thirty hour incubation period. However, saturation of the intracellular pool took place after ca. ten hours of incubation. Addition of leukocytic endogenous mediator, LEM, to cultures of rat hepatocytes caused a profound increase in the relative concentration of acute-phase proteins secreted into the culture medium.

Amino Acids↗
PubMed1980

The effect of fibrinopeptides A and B on experimental allergic encephalomyelitis.

Experimental allergic encephalomyelitis (EAE) was induced in guinea-pigs and rats by sensitization with encephalitogenic antigens and adjuvant. Treatment of the experimental animals by daily intraperitoneal injections with human fibrinopeptides A and B proved to produce significant changes in the course of EAE. In the treated animals as compared to controls the clinical neurological signs of the disease wuch as the number, the severity and the duration of pareses were diminished. Furthermore, the inflammatory alterations of vasopermeability associated with extravasation of plasma proteins and oedema of the neuroparenchyma were significantly less pronounced in the fibrinopeptide-treated animals. Finally, a significantly higher titre of circulating immune complexes was observed in the serum of these animals. However, the treatment with fibrinopeptides A and B did not alter the specific immune response to the antigenic challenge. No differences in anti-basic protein and anti-brain antibody production were observed. The characteristic cellular infiltrates of EAE also showed no significant qualitative or quantitative differences between fibrinopeptide-treated animals and the saline-treated controls. These results suggest that fibrinopeptides A and B act primarily on the immunologically non-specific phase of EAE development by reducing the severity of vascular permeability alterations.

Animals↗
PubMed1980

[Anaesthesia and intraocular pressure (author's transl)].

Almost every modern anaesthetic has an impact on the complex physiology of the intraocular pressure. The different factors influencing the intraocular pressure are discussed. With the exception of succinylcholine and ketamine all other substances used in modern anaesthesia produce a more or less significant reduction of the intraocular pressure. Hence, the anaesthesiologist disposes in general of a great variety of drugs to conduct an anaesthesia that is well adapted to the physiological requirements of the eye. Yet, he may still encounter some difficulties in emergency-situations, like a perforating eye trauma in a patient with a full stomach. Fazadinium may be a usefull alternative to succinylcholine in these situations, as its rapid onset of action is not accompanied by a rise in the intraocular pressure. Some other measures to reduce the intraocular pressure intraoperatively are also mentioned, like controlled hypotension, osmotic diuresis and inhibition of the carbonic anhydrase.

Anesthesia, General↗
PubMed1979

Immunoelectron-microscopical localization of in vivo-bound complement C3 in bullous pemphigoid with the use of the peroxidase-antiperoxidase multistep technique.

In vivo-bound complement C3 in bullous pemphigoid was precisely localized by means of the peroxidase-antiperoxidase multistep technique. In the nonbullous lesions peroxidase deposits filled the lamina lucida completely, i.e., the space between lamina densa and the cell membranes of the basal cells. In developed bullae, the reaction product was located both on the lamina densa and on the surface of separated keratinocytes. These findings may indicate that antigen components in bullous pemphigoid are localized almost exclusively within the ground substance which fills the lamina lucida and covers the surface of the basal cells.

Aged↗