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Biomedical subjects

M Haider

Publications and source records attributed to M Haider.

At least 37 records · Page 2Linked to original sources
PubMed1991

[Effect of molsidomine on thrombocyte aggregation in unstable angina pectoris after parenteral administration of nitroglycerin].

In the present study, we took whole blood from 12 patients treated with heparin, acetylsalicylic acid, and nitroglycerin i.v., to measure the aggregability of platelets after acute and prolonged i.v. application of nitroglycerin and after oral application of molsidomine. Aggregation was induced by platelet-activating-factor (PAF). As a measure for platelet aggregability, we determined the PAF-concentration needed to induce irreversible aggregation (threshold dose) and the maximum slope of the aggregation curve with 50 nM PAF. At the beginning, 1 h after the onset of nitroglycerin infusion (3 mg/h), 24 h and 1 h after increasing the nitroglycerin dose (5 mg/h), neither the maximum slope nor the threshold dose for PAF-induced aggregation differed significantly. However, after additional oral application of molsidomine the maximum slope of the aggregation curve decreased significantly. These data indicate that molsidomine decreases the aggregability of platelets in patients, even after pretreatment with heparin, acetylsalicylic acid, and nitroglycerin.

Angina, Unstable↗
PubMed1991

[Current methods in blood preservation: recovery of blood components using a multi-bag system].

A new method of blood preparation by use of a multiple plastic bag system is prescribed. Buffy coat free red cell suspensions in additive solution (SAG-M), fresh frozen (recovered) plasma and random platelet concentrates can thus be produced. Apart from the so far clinically not instantaneously available stored platelets the storage time of the red cells is remarkably increased up to 42 to 49 days and the cellular contaminations (red cells and leucocytes in platelet concentrates, thrombocytes and leucocytes in FFP) are markedly diminished leading to a higher quality of these components. The Red Cross Blood Transfusion Service of Upper Austria presents its data obtained by the use of a quadruple plastic bag (RC Transfusion Production Center Eugendorf/Salzburg) with cellular contamination parameters far below the generally accepted limits. Apart from the increased quality of the components a very high level of clinical acceptance concerning especially the stored random platelet concentrates has been experienced. In conclusion the necessity of changing to a multiple bag system is strongly emphasized thus not only better fulfilling the clinical needs for the different blood components but also delivering higher qualities. Red cell preparations containing the buffy coat should therefore not be used any longer.

Blood Coagulation Factors↗
PubMed1991

[Standards for preclinical resuscitation--requirements for efficient therapy and scientific analysis. A prospective study using as an example the combined emergency medical service of the Munich administrative district and capital].

A standardized treatment protocol is essential for scientific evaluation of parameters influencing the outcome and survival of patients who have suffered cardiac arrest in a non-hospital situation. In addition, a standardized therapy algorithm permits effective, time-saving interaction of all members of the emergency team who work together to perform cardiopulmonary resuscitation (CPR) in any emergency outside the hospital. This paper gives the results obtained in 50 patients in whom on-the-spot resuscitation was performed by a specially trained team [emergency medical team (EMT) + on-scene physician] using an ACLS (advanced cardiac life support) protocol modified from the AHA (American Heart Association) standard. Two different algorithms were used one for ventricular fibrillation (VF) and pulseless ventricular tachycardia and one for asystole and pulseless bradycardia. When indicated, countershocks were first administered at a continuous energy level of 360 J, up to three times one after the other. All patients then received epinephrine intratracheally, 2 mg, immediately after intubation. In the case or persisting asystole a further 2-mg dose of epinephrine and then one 5-mg dose were given i.v. in keeping with the ACLS protocol. In the case of persisting VF or pulseless tachycardia we gave one 100-mg dose of lidocaine i.v. and then performed the next countershock at the same energy level. The time the team members actually needed for the single steps of the ACLS protocol was meticulously documented with the aid of a stop watch.(ABSTRACT TRUNCATED AT 250 WORDS)

Algorithms↗
PubMed1990

Occurrence of infraslow potential oscillations in relation to task, ability to concentrate and intelligence.

The occurrence of infraslow potential oscillations (ISPOs) of the brain was investigated during a listening and a resting condition in 44 subjects (Ss) with high (HAC) and low ability to concentrate (LAC). The occurrence of ISPOs was found in 36% of the Ss. While in the HAC group the occurrence of ISPOs did not change from listening to resting, in the LAC group Ss with ISPOs were affected by experimental conditions, showing ISPOs during the listening condition. For Ss with ISPOs only during listening a lower score was found for ability to concentrate, suggesting ISPOs as a possible underlying mechanism. For Ss with stable ISPOs a higher I.Q. was found compared to Ss without ISPOs.

Adult↗
PubMed1989

Filtered dark-field and pure Z-contrast: two novel imaging modes in a Scanning Transmission Electron Microscope.

For the investigation of biological objects with a Scanning Transmission Electron Microscope (STEM) the dark-field imaging mode is the one used most often. We will show, regarding calculations that we have done which took into account the finite angle of the illumination and multiple scattering processes, that the collected amount of inelastically scattered electrons with an annular dark-field detector is higher then normally expected. According to the above calculations, we designed a new detection system to enable us to acquire three different images (inelastic, filtered dark-field and filtered bright-field) simultaneously.

Mathematics↗
PubMed1989

The electromyographic DC potential as a correlate of muscular activity.

The present experiment was undertaken to demonstrate the effect of muscular force as well as duration of muscular work on the electromyographic (EMG) DC potential. Thirty subjects had to lift different weights by flexing the right forearm within a defined and constant setting for 20 s. The experimental variables were weight (0.5, 1, 2, and 3 kg) and time. The EMG was recorded from the belly of the right biceps brachii muscle in a quasi-unipolar manner and split into an integrated ac channel (IEMG) and a dc channel (DC-EMG). The average IEMG showed a ramp-like shape. Analysis showed a positive relationship for weight (p less than 0.0001) and time (p less than 0.0001) with the IEMG. The average shape of the DC-EMG showed a negative initiation potential, a monotonically increasing negative potential during contraction (contraction potential), a positively peaking off potential and a slow return to baseline (after potential). Analyses of variance demonstrated a significant (p less than 0.001) relationship of weight to the magnitude of the initiation and the termination potential. Regression analyses displayed an inverse relationship of time to the termination (p less than 0.01) and to the resolution potential (p less than 0.001). The DC-EMG showed higher peaks (initiation and termination potential) for heavier weights. For the termination and after potential less positive deflections were found with increasing time (fatigue). A control condition (isometric contraction) indicated that the initiation, contraction, and termination potential of the DC-EMG may also be related to aspects of the movement. Results suggest that the DC-EMG is a more complex measure of muscular activity than the IEMG.

Adult↗
PubMed1989

[Clostridium infection in the puerperium following cesarean section].

Clostridium perfringens infections in the puerperal period are rare. A 22-year old patient, after caesarean section at another hospital, was admitted to our clinic showing clinical signs of haemolysis, slight uraemia, a crepitation of tissue and sonographical signs of air bubble formation in the uterus. Since clostridium perfringens infections show a high mortality rate, early operative measures under high-dose Penicillin treatment are indicated. In this case, hysterectomy and salpingectomy were performed. Both ovaries were unaffected and could be conserved. In addition, a peritoneal lavage was done. Our patient was discharged as cured after a postoperative course without any complications. There is no evidence in the literature for the efficacy of either antitoxin treatment or a high oxygen therapy.

Adult↗
PubMed1989

Stabilization and prevention--a theoretical framework for environmental hygiene.

A theoretical framework for research about problems of environmental hygiene and the conception of strategies for their solution is described. In this context experiences with environmental impact assessments are analysed and proposals for improvements of such assessments are worked out. The strategies for protecting and shaping environments are categorised in 3 groups: defensive, constructive and evolutionary. Conceptual schemas for man-environment and socio-environment systems are presented. Evolutionary strategies for the development of these systems are formulated analogue to evolution strategies of ecosystem development. The effects of destabilization on health risks in man-environment systems are partially tested in a longitudinal study on effects of shiftwork. The possibilities of destabilization, restabilization and prevention of health risks in socio-environment systems are discussed.

Environmental Exposure↗
PubMed1988

Changes in discrimination learning and brain activity (ERP's) due to combined exposure to NO and CO in rats.

Carbon monoxide (CO) and nitric oxide (NO) are air pollutants frequently appearing in combination. Information available on the mechanisms of NO intoxication suggests that in mixtures with CO additive effects should be assumed. In this study CO and NO-induced changes and their interaction were investigated at different levels of integration: carboxyhemoglobin (COHb) and methemoglobin (met-Hb) formation as well as centrally mediated effects were analyzed using evoked potential techniques and behavioral data from a complex discrimination learning experiment. Slight enhancements of COHb and met-Hb concentrations were seen for the combined CO + NO exposure conditions at low and high exposure levels when compared to isolated exposure conditions. The performance decrease was clearly higher under NO exposure than under CO exposure. Decrements were overadditive when simultaneous CO + NO exposure was used in higher concentration. Both gases affected early evoked potential components (P10, N30) in the same way: latencies were prolonged and amplitudes increased. Later potential components were differently influenced by CO and NO. Mainly the N150 amplitude was decreased in NO exposure and increased in CO conditions. N150 amplitude was also decreased after combined CO + NO exposure. At high levels this effect was overadditive indicating a dominant role of NO in the CO + NO combinations used in this experiment.

Animals↗
PubMed1987

Thoracic duct lymph and PEEP studies in anaesthetized dogs. I. Lymph formation and the effect of a thoracic duct fistula on lymph flow.

The effect of positive end-expiratory pressure ventilation (PEEP, 11-12 mmHg, 60-90 min without, 19 h with circulatory support) on fractional escape rate of plasma proteins (FER), and on thoracic duct lymph flow draining against jugular venous (LFJVP) or atmospheric pressure (LFAP) was studied in anaesthetized dogs. FER was 10.8%/h, 15.3%/h, and 8.5%/h before, during, and after PEEP, respectively, indicating augmented lymph formation probably due to the increase in venous pressure from 4.8 to 10.8 mmHg during PEEP. LFJVP was 39 microliter/min per kg before PEEP, decreased transiently during PEEP but the steady state value (up to 19 h) was not different from control, and increased transiently after PEEP. LFAP was 37, 80, and 38 microliter/min per kg before, during, and after PEEP, respectively. Long-term PEEP increased LFAP fourfold. Changing the drainage mode during PEEP yielded an immediate increase from LFJVP = 34 to LFAP = 79 microliter/min per kg and an instantaneous reduction from LFAP = 95 to LFJVP = 35 microliter/min per kg. Lymph protein concentration and protein lymph/plasma ratio increased concomitantly with LFAP during PEEP suggesting augmented hepatic contribution to LFAP, augmented intestinal contribution was revealed by labelling intestinal lymph using olive oil orally, muscular lymph flow was not increased as shown by i.m. Evans blue. In conclusion, the augmentation of venous pressure by PEEP promotes capillary filtration but obstructs lymph drainage from the thoracic duct into the jugular vein. PEEP imbalances formation and return of lymph and affects the development and removal of oedema.

Animals↗
PubMed1987

Thoracic duct lymph and PEEP studies in anaesthetized dogs. II. Effect of a thoracic duct fistula on the development of a hyponcotic-hydrostatic pulmonary oedema.

PEEP impedes thoracic duct drainage (LF). This can be counteracted by a thoracic duct fistula. Consequently, lung oedema (LOE) should develop during PEEP more slowly with LF at atmospheric pressure (LFAP) than with LF against jugular venous pressure (LFJVP). In 12 anaesthetized dogs LOE was produced by Ringer's solution i.v. (2.5 ml/min per kg) for 6 h during PEEP (10 mmHg) with either LFAP or LFJVP. Ringer's + PEEP greatly increased aortic, pulmonary artery and wedge pressures, JVP, and cardiac output. Colloid osmotic pressures in plasma and lymph were drastically reduced, pulmonary effective filtration pressure (EFP) rose by about 20 mmHg. LFJVP increased 7-fold, LFAP about 19-fold, the respective loss of plasma proteins was 1.83 and 1.06 g/kg during 6 h. Thermal-dye extravascular lung water showed an increment of 68 with LFJVP versus 43 microliter/h/g per mmHg with LFAP. Final lung water content was at any delta EFP (12.8-31.9 mmHg) lower with LFAP than with LFJVP amounting 512 with LFJVP versus 377 microliters/g/per mmHg with LFAP. LFAP decreased the development of LOE during PEEP by bypassing the PEEP-induced high JVP and thus facilitating the removal of interstitial fluid. It is hypothesized that a thoracic duct fistula might aid the treatment of patients with LOE due to ARDS and therefore requiring high levels of PEEP.

Animals↗
PubMed1987

Systemic angioendotheliomatosis of the lung.

Systemic angioendotheliomatosis is a very rare malignant disease characterized by intravascular neoplastic proliferation of reticuloendothelial cells. According to the clinical features three different types of prognostic value can be distinguished: Exclusive skin involvement; Progressive skin lesions disseminating to internal organs; Aggressive and lethal type affecting primarily internal organs. Until now about 60 cases of systemic angioendotheliomatosis have been reported in the literature. Here we describe the first well-documented case with almost isolated lung involvement. The presentation of morphologic and clinical signs and differential-diagnostic considerations are followed by a critical review of the literature.

Aged↗
PubMed1987

[Determination of plasma volume with indocyanine green].

In 31 anesthetized dogs, the distribution volume (Vd) of indocyanine green (ICG, Cardiogreen) was compared to that of Evans blue (EB), which is considered to represent plasma volume. Vd was computed from the injected amount of indicator and the indicator concentration in plasma at time zero, which was obtained by extrapolation of the monoexponential decay of the indicator concentration. The decay was assessed by eight plasma samples from 10-60 min and from 5-12 min after injection of EB and ICG, respectively. EB was measured in a spectrophotometer at 640 and 720 nm; ICG was measured in a spectrophotometer at 805 nm or in a cuvette densitometer with two light sources (LEDs) of 800 and 900 nm. The decay of EB had a half-life of about 330 min, corresponding to a disappearance rate of about 13%/h; the half life of ICG was about 8.0 min, equivalent to a fractional disappearance of about 9%/min. Vd (EB) was 55 +/- 11 (n = 31) ml.kg-1 (mean +/- SD), Vd (ICG) was 55 +/- 12 (n = 20) and 56 +/- 10 (n = 20) ml.kg-1 when ICG was measured in the densitometer or spectrophotometer, respectively. The ICG clearance was about 5 ml.min-1 per kilogram. The accuracy of the determination of plasma volume by ICG was tested in four experiments in two splenectomized dogs. Changes in plasma volume by volume load, enforced diuresis, hemorrhage, and reinfusion were determined by ICG and compared to the theoretical changes calculated from the hematocrit and removed volumes. The mean difference between measured and calculated values was 1.3 +/- 3.4% (n = 14).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗