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Biomedical subjects

M Wendt

Publications and source records attributed to M Wendt.

At least 127 records · Page 7Linked to original sources
PubMed1987

Gravitropic bending of cress roots without contact between amyloplasts and complexes of endoplasmic reticulum.

The polar arrangement of cell organelles in Lepidium root statocytes is persistently converted to a physical stratification during lateral centrifugation (the centrifugal force acts perpendicular to the root long axis) or by apically directed centrifugation combined with cytochalasin-treatment. Lateral centrifugation (10 min, 60 min at 10g or 50g) causes displacement of amyloplasts to the centrifugal anticlinal cell wall and shifting of the endoplasmic reticulum (ER) complex to the centripetal distal cell edge. After 60 min of lateral centrifugation at 10g or 50g all roots show a clear gravitropic curvature. The average angle of curvature is about 40 degrees and corresponds to that of roots stimulated gravitropically in the horizontal position at 1 g in spite of the fact that the gravistimulus is 10- or 50-fold higher. Apically directed centrifugation combined with cytochalasin B (25 micrograms ml-1) or cytochalasin D (2.5 micrograms ml-1) incubation yields statocytes with the amyloplasts sedimented close to the centrifugal periclinal cell wall and ER cisternae accumulated at the proximal cell pole. Gravitropic stimulation for 30 min in the horizontal position at 1 g and additional 3 h rotation on a clinostat result in gravicurvature of cytochalasin B-treated centrifuged (1 h at 50 g) roots, but because of retarded root growth the angle of curvature is lower than in control roots. Cytochalasin D-treatment during centrifugation (20 min at 50 g) does not affect either root growth or gravicurvature during 3 h horizontal exposure to 1-g relative to untreated roots. As lateral centrifugation enables only short-term contact between the amyloplasts and the distal ER complex at the onset of centrifugation and apically directed centrifugation combined with cytochalasin-treatment even exclude any contact the integrity of the distal cell pole need not necessarily be a prerequisite for graviperception in Lepidium root statocytes.

Brassicaceae↗
PubMed1987

Viscoelasticity of tracheobronchial secretions in high-frequency ventilation.

The effects of high-frequency ventilation (HFV) on the rheological properties of tracheobronchial secretions were investigated in vitro. The mucus was obtained by suction from 16 patients after major surgery of the larynx or hypopharynx. After short centrifugation, the mucus was treated with high-frequency vibrations of 3 or 30 Hz for 10 min in a chamber saturated with water vapor. The mucus was separated by a nonpermeable membrane from the ventilator's gas stream. Maximal, minimal, and mean viscosity were determined by a modified capillary viscosimeter. Under high-frequency vibrations, maximal, minimal, and mean viscosity slightly increased (p less than or equal to .001). Conversely, the mean viscosity of control samples did not change significantly. These findings indicate that high-frequency vibrations do not improve mucous rheology. Observed beneficial effects of HFV on mucociliary clearance may be caused by changes in the mucous subphase during HFV.

Bronchi↗
PubMed1987

[ABS 800: expanding the possibilities of respiratory therapy].

A new module of the Dräger modular device system provides a means for demand CPAP (to increase FRC) and assisted spontaneous breathing. Both features together may largely increase the potency of ventilatory therapy for spontaneously breathing patients. The machine may reduce the need for full ventilatory support in acute respiratory failure, but also provides a valid and rational tool for respiratory therapy.

Critical Care↗
PubMed1987

[Stomach torsion in swine].

Sudden death in mature sows due to torsion of abdominal organs (stomach, spleen, liver) is described. Hepatic torsion is seen only separately, but gastric torsion and torsion of spleen appear by themselves as well as in combination with each other. Often no clinical symptoms are observed. Acute cardiovascular failure is responsible for death in these sows. Authors unanimously report on feeding as a possible aetiological factor. Both the composition and technique of feeding should therefore be examined in problematic live stock. Excitement and excessive movements before and during feeding as well as the rapid intake of large amounts of water and feed seem to predispose to the development of gastric dilatation or torsion in sows. Suitable prophylactic measures should be taken.

Animals↗
PubMed1986

[The accuracy of oxygen flowmeters].

The accuracy of oxygen flowmeters is a prerequisite for a predictable oxygen therapy. As a flowmeter seems to be of unlimited service life, they are often not serviced regularly. This can result in errors in the actual oxygen flow of as much as 50% of the preset value.

Humans↗
PubMed1986

[Defense mechanisms of the macro-organism in bacteriuria in chronic pyelonephritis].

In the course of 4 years we isolated 193 E. coli strains of 55 patients with chronic pyelonephritis. In patients with obstructive chronic pyelonephritis the mean value of the immunofluorescence titre (in the serum) to the E. coli strain excreted in the urine as well as the total complement were significantly increased, the serum lysozyme was significantly lower than in patients with non-obstructive chronic pyelonephritis. A relation to the activity of the disease was existing only in the non-obstructive chronic pyelonephritis, where in the active stage the total complement was significantly decreased, the complement factors C3 and C4 as well as the urine lysozyme were significantly increased in comparison to the inactive stage. 94.64% of all immunofluorescence titres obtained to the homologous strain in the patients' serum were above the border of the normal area of 1:40. A relation between level of the titre and activity of the disease could not be established. No significant differences could be proved between the titres taken to serum-sensitive and serum-resistant strains. In 32.73% of the patients we observed disturbances of the serum bactericidia against the homologous serum-sensitive E. coli urine strain at one or several points. They fall to equal shares to patients with obstructive and non-obstructive chronic pyelonephritis and were found at 66.67% in the active stage of the two forms of the disease. In patients with and without disturbances of bactericidia no significant differences in the total complement, in the complement factors C3 and C4, the C3-activator, the serum lysozyme and the immunofluorescence titres could be proved.

Antibody Formation↗
PubMed1986

[Tolerance of 3.5 percent plasma protein solution].

In a prospective study we found 112 patients out of 9549 who had been given 3.5% plasma protein solution during the preceding year but no other blood derivatives and who had not received any immunosuppressive treatment. 68 patients agreed to be tested for sensitisation to 3.5% plasma protein solution. An intracutaneous test was performed as screening test. Two patients had a false positive reaction, but one of them had urticaria factitia and therefore a positive reaction to NaCl 0.9%. The other patient showed circumscribed reddening in the early phase only, whereas later readings were negative. Neither the test of total IgE by Paper Radio Immuno Sorbent Test (PRIST) nor the test for specific IgE antibodies by Radio Allergo Sorbent Test (RAST) showed any positive results. According to these findings there was no sensitisation to 3.5% plasma protein solution.

Adolescent↗
PubMed1986

[High-dose piritramide basal anesthesia in experimental anesthesia and surgery].

On the basis of investigations of three groups of dogs (7 in each) the effects of high dosage piritramide anesthesia were analyzed. Using a standardized technique no significant changes in hemodynamics and microcirculation were found during 4 h. So variations in the "steady-state" must be attributed to additional medication or therapeutic intervention. High dosage piritramide anesthesia has been applied in more than 250 animal experiments.

Anesthesia↗
PubMed1984

[Adjustment of synchronized intermittent ventilation with the Drager Company's SIMV Pulmolog].

When choosing an IMV frequency in a respirator, the aim should be to guarantee a minimum of ventilation. With most respirators the "time-window" for the synchronisation of the mandatory stroke volume is within the ventilatory cycle. Thus, the IMV frequency corresponds to the adjusted minimum mechanical ventilation frequency and can be increased only by the patient's spontaneous breathing activity. With the Dräger "Pulmolog", however, the spontaneous breathing phase--not the ventilatory cycle--is already determined by choosing the IMV frequency. This difference is most important for daily clinical practice, as the minimum IMV frequency may be below the adjusted one. The manufacturer has reacted by changing the data on the manufacturer's label.

Humans↗
PubMed1984

[A new weaning procedure (inspiratory flow assistance)].

Inspiratory Flow Assistance (IFA) refers to new breathing mode, able to diminish the work of breathing of a patient during spontaneous breathing with a respirator. By combination of IFA with CPAP or IMV it is especially useful during weaning from the respirator. The part of work of breathing done by the respirator. The part of work of breathing done by the respirator is only indirectly determinable. The measurements done on 10 long term ventilated patients during the weaning period show that only an IFA up to an airway pressure of 10 cm H2O above CPAP guarantees mainly spontaneous breathing, while an IFA up to higher airway pressures is more and more similar to an assisted ventilation.

Adult↗
PubMed1984

[Cuff protection for nasotracheal intubation].

The passage of a tube through the nose to the epipharynx is potentially dangerous during the nasotracheal intubation because of the possibility of cuff damage, obstruction of the tube, the impossibility of advancing the tube and contamination. It seems therefore useful to protect the cuff e.g. by a finger stall, but using this procedure complications can occur which are reported. A better solution to protect the cuff will be shown.

Humans↗
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↗