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Biomedical subjects

R Ritz

Publications and source records attributed to R Ritz.

At least 73 records · Page 4Linked to original sources
PubMed1984

Free calcium response to adrenaline in platelets of normal and hypertensive (untreated and treated) subjects.

That adrenaline is involved in the pathophysiology of essential hypertension (EHT) is suggested by the observed elevation of plasma adrenaline concentration in some patients. Adrenaline, by stimulating the alpha-2 adrenoceptor, causes vasoconstriction in the smooth muscle cell and initiates shape change and aggregation in platelets. Therefore, the effect of adrenaline on intracellular free calcium concentration ([Ca2+]i) in the platelets of hypertensive subjects was investigated as a model for vascular smooth muscle. Platelets from untreated patients with EHT had an elevated [Ca2+]i and incubation with adrenaline for 30 min caused a greater increase in [Ca2+]i in treated patients with EHT than in normotensive controls. This long-term effect of adrenaline was possibly linked to a defective calcium extrusion mechanism in hypertension. No immediate effect was observed on [Ca2+]i by PGI2 and adrenaline, while both modulated [Ca2+]i if the platelets were stimulated with thrombin. PGI2 prevented the thrombin-induced increase in [Ca2+]i and adrenaline antagonized the effect of PGI2. Platelets from untreated patients with EHT exhibited an increased sensitivity to thrombin and adrenaline when compared to normotensive and treated hypertensive subjects. It is suggested that these supersensitivities are related to the elevated [Ca2+]i in untreated hypertensive patients.

Adolescent↗
PubMed1984

[Medical aspects of the treatment of acute coronary disease].

Progress in the drug therapy of arrhythmias and congestive heart failure following acute coronary heart disease and attempted infarct size reduction are discussed. A schedule of diagnostic and therapeutic procedures is proposed. Corresponding to present knowledge of the pathophysiology of "unstable angina pectoris" drug therapy can be more specifically administered in this form of acute coronary heart disease.

Angina, Unstable↗
PubMed1983

[Intensive surveillance in poisoning caused by tricyclic antidepressive agents].

Monitoring in an intensive care unit after intoxication with tricyclic antidepressants for 48-72 hours was reevaluated in a retrospective study of 57 patients. As described in the recent literature, severe neurologic (coma grade III and IV, seizure or respiratory insufficiency) or cardiovascular complications (bradycardia, ventricular tachycardia, hypotension, were not found after 24 hours of intensive monitoring. More prolonged monitoring control no longer appears necessary.

Antidepressive Agents, Tricyclic↗
PubMed1983

Alpha 2 adrenoceptor-mediated vasoconstriction of arteries.

We investigated the possibility that adrenoceptors of the alpha 2 subtype mediate vasoconstriction of arteries in response to administered catecholamines. Clonidine, which in vitro, stimulates alpha 2-adrenoceptors was infused into a brachial artery in 12 subjects (0.48 micrograms/min/100 ml tissue for 3 min). Afterward, prazosin was infused intraarterially in the first six subjects (0.5 micrograms/min/100 ml for 10 min) and in the remaining subjects, phentolamine was infused (0.12 micrograms/min/100 ml) for 10 min. Subsequently, the clonidine infusion was repeated. Clonidine decreased forearm blood flow from 3.5 +/- 0.52 to 1.8 +/- 0.32 in the first six subjects and from 4.2 +/- 0.84 to 2.7 +/- 0.61 ml/min/100 ml in the other subjects. Alpha 1-Adrenoceptor blockade by prazosin increased forearm blood flow by 122.7 +/- 33.8% and combined alpha 1 and alpha 2 blockade by phentolamine by 127.2 +/- 29.9%, indicating much the same degree of postjunctional alpha-adrenoceptor blockade. Alpha 2-Adrenoceptor-mediated vasoconstriction by clonidine was abolished after phentolamine (9.1 +/- 2.29 and 9 +/- 2.51 ml/min/100 ml) but was still present after prazosin (7.8 +/- 1.7 and 4.8 +/- 1.6 ml/min/100 ml). The results suggest that, apart from the classical alpha 1 adrenoceptor, there is a second type of adrenergic receptor on smooth muscle cells that can mediate vasoconstriction, resembling the alpha 2-adrenoceptor pharmacologically.

Adult↗
PubMed1982

Sequential treatment of arterial occlusions with porcine plasmin and low dose streptokinase.

Sequential treatment of arterial occlusions of the leg with porcine plasmin and low dose streptokinase results in a strong systemic proteolysis as already seen in deep leg vein thrombosis. In 31 of 45 patients the blood flow through major arterial segments could be restored. Thrombolytic success is possible within the first two treatment days but for the majority of the cases fibrinolytic therapy for 3-6 days is needed. On the average treatment was 1 day shorter than in DVT cases. No statistical relationship between local thrombolysis and systemic proteolysis was detected. The thrombolytic efficacy of this regimen compares favourably with earlier experience on fibrinolytic therapy in arterial occlusions.

Adult↗
PubMed1982

Sequential treatment of deep leg vein thrombosis with porcine plasmin and low dose streptokinase.

Sequential treatment of deep leg vein thrombosis with porcine plasmin and low dose streptokinase (10,000-20,000 U/h) produces strong systemic fibrinolysis as demonstrated by the sustained decrease of euglobulin lysis time, of thromboplastin time values in percent, fibrinogen and factor V levels. There is a statistically significant negative correlation between thrombolytic results and euglobulin lysis time. Treatment period below 3 days are unlikely to give satisfactory results. Occluded vein segments with an apparent median age of 4 days including thrombi older than 10 days (20% of cases) are cleared with an average chance of 50%. Complete dissolution of all thrombi proximal to the crural veins has been demonstrated in 47/114 = 41.2%, some thrombolytic effects in 31/114 = 27.2% and treatment failure in 36/114 = 31.6%. The data favour laboratory monitoring of thrombolytic therapy.

Adult↗
PubMed1982

Side effects of thrombolytic treatment with porcine plasmin and low dose streptokinase.

In the sequential thrombolytic therapy with porcine plasmin and low dose streptokinase side effects are mainly due to bleeding, intolerance reactions are less important. Treatment had to be prematurely stopped in 42 (37%) of 114 DVT cases because of severe bleeding and in 12 (10%) due to intolerance reactions. The corresponding figures for the 45 cases with arterial occlusions are 15 (33%) and 2 (4%) respectively. The intensity of systemic proteolysis as represented by the thromboplastin time is significantly correlated with haemorrhagic manifestations. Macrohematuria and bleeding from puncture sites are the most frequent haemorrhagic complications followed by spontaneous bleeding into skin and muscles. Non-fatal intracranial bleeding occurred in 1 DVT case (0.9%) and in 2 patients with arterial occlusions (4.4%). The benefit of this potent thrombolytic regimen would greatly improve if a strong reduction of premature treatment stop could be achieved.

Animals↗
PubMed1982

[Follow-up of intensive medical care patients].

Increasing limitations on personnel and material in intensive care render a reevaluation necessary. Follow-up of critically ill patients might be a useful contribution to this. In 330 patients the situation during intensive care and the subsequent stay on the ward, as well as physical and psychological status 3 years later, were analyzed. In 96% the acute event necessitating intensive care corresponded to a preexisting chronic illness. Although the mean stay of 3,6 days in ICU was relatively short, total time of hospitalization exceeded that of patients who did not undergo intensive care. Three quarters of the 330 patients survived ICU and two thirds the subsequent hospitalisation. Half of the patients were still alive three years later, most under medical supervision for the same illness. 89 Patients could be followed up after three years; 84% were physically independent and 53% were at work, but 20% of these had had to change jobs. The later outcome in patients ventilated during intensive care was inferior in all respects. Comparing the quality of life to 1977, 33% of the patients described their physical capacity and 14% their mental activity as reduced. One third of the patients had specific memories of the stay on the ICU, such as pain, fear of being alone, of the illness or of the technical environment. In conclusion, three years after intensive care half of the patients had survived and in most of the cases a qualitatively satisfactory life style was possible.

Adolescent↗
PubMed1982

[Continuous computer-assisted monitoring].

Optimal monitoring of vital parameters in critically ill patients should be performed continuously with non-invasive and automatic methods including trend presentation of the data. Continuous measurements are now in frequent use in intensive care units, and non-invasive techniques are being increasingly explored. Besides automatic registration, computerization of monitoring allows trend presentation of the measured values and thereby improves diagnostic and therapeutic procedures. The characteristic peculiarities of a computer, i.e. acquisition, computing and presentation of the data, as well as storage capacity, enable simultaneous monitoring of several complex parameters, as is demonstrated by arrhythmia monitoring systems already in routine use. Optimal patient surveillance is described in three practical examples of computer application.

Arrhythmias, Cardiac↗
PubMed1982

[Slower lidocaine elimination and dose adjustment in patients with heart failure].

In 21 patients with acute coronary artery disease the influence of cardiac failure on the elimination of lidocaine (L) was evaluated by repeated serum level measurements during and after a therapeutic L-infusion. Lidocaine clearance (Cl) was less than 8 ml/min/kg in 9 of 13 cases with congestive heart failure (CHF), while in 7 out of 8 patients without CHF Cl-values were 8-12 ml/min/kg. Due to wide interindividual variability in the CHF group, however, mean values were not significantly different: 7.3 +/- 2.9 vs. 9.52 +/- 1.54 ml/min/kg (p greater than 0.05). In 3 patients receiving a simultaneous nitroglycerine infusion Cl was greater than 10 ml/min/kg despite clinical signs of CHF. The t 1/2 of L was significantly prolonged in patients with CHF: 4.29 +/- 2.14 vs. 2.43 +/- 0.58 h (p less than 0.05). It was not possible to determine individual L-dose requirements by bedside clinical examination alone. Serum level monitoring is therefore recommended in order to optimize L-therapy in patients with life-threatening arrhythmias, severe congestive heart failure and hypotension.

Arrhythmias, Cardiac↗
PubMed1982

Plasma adrenaline and noradrenaline in patients with acute myocardial infarction. Relationship to ventricular arrhythmias of varying severity.

Plasma adrenaline (A) and noradrenaline concentrations (NA) were determined in 41 patients admitted to the coronary care unit (CCU). Eleven with suspected acute myocardial infarction (AMI), subsequently excluded as a diagnosis, had significantly elevated A and NA compared with 20 normal resting subjects. Patients with proven infarcts but no ventricular fibrillation had even higher levels of A and NA. Nine patients with ventricular fibrillation as a complication of AMI showed the highest plasma catecholamine values on admission. Patients with AMI and congestive heart failure exhibited substantially increased A, while NA was only slightly elevated compared with that of AMI patients without congestive heart failure. High plasma catecholamines and the relationship between adrenaline and the severity of ventricular arrhythmias suggest that the sympathetic nervous system plays an important role in sustaining a vicious circle of increased myocardial damage and increased irritability during the acute phase of AMI.

Adult↗