[Prazosin in the treatment of hypertension: effect on lipid metabolism]

In an open, non-comparative study, the effect of Prazosin, a selective and competitive inhibitor of alpha-adrenergic receptors, on blood pressure and lipid metabolism was studied in out-patients with hypertension. The pronounced antihypertensive effect of this vasodilator was confirmed. In almost all patients, i.e. in 144 of 171 patients with monotherapy, Prazosin caused a significant decrease of diastolic blood pressure within 3 to 6 weeks (in sitting position reduction to values below 90 mm Hg). This confirms the established antihypertensive effect due to vasodilation. In addition, Prazosin therapy is associated with a significant reduction in total cholesterol (p less than 0.001), a significant increase of HDL-cholesterol (p less than 0.001), a significant reduction of triglycerides (p less than 0.01) during the study period of 26 weeks. Prazosin monotherapy had a more pronounced influence on serum lipids than the combination of Prazosin with a diuretic. Prazosin was tolerated well; only during the first treatment weeks, a higher frequency of side effects due to abrupt reduction of blood pressure was observed, closely correlating with a too rapid increase of daily dose. Due to its proven antihypertensive effect and its favorous influence on lipid metabolism, Prazosin is suited for long-term treatment of hypertension, thus reducing two major risk factors, associated with coronary heart disease.

[Arthroscopic diagnosis of the wrist joint]

Arthroscopy of the wrist is a helpful diagnostic procedure. The technique of the arthroscopy of the wrist is described. Initial experience in 22 diagnostic arthroscopies of the wrist is recounted. In six cases operative procedures followed the diagnostic arthroscopy.

[Comparison between 2 methods of determining photon-induced air activity around medical accelerators]

The authors compare two different methods to determine the activity of the air induced by the bremsstrahlung of medical accelerators. The activities of the air resulting from maximum photon energies of 16 to 42 MeV are measured with a proportional counter tube ("direct measurement") and by means of activation analyses of imidazole, triazole, malonic acid, and urea specimens ("indirect measurement"). The results are compared.

The exocytosis of human blood platelets. A fast freezing and freeze-substitution analysis

Human platelets were stimulated with thrombin or collagen in order to induce the release of alpha-granules and dense bodies. The platelets were cryofixed in various stages of exocytosis and subsequently cryosubstituted in acetone containing 4% osmium tetroxide. The platelets embedded in araldite were analyzed in serial sections. The initial changes of the alpha-granules were characterized by an impressive swelling and a dispersal of the granular matrix. Swollen alpha-granules in different stages of exocytosis formed contacts. Between the attached membranes of the alpha-granules electron-dense connections were sometimes observed. In a later stage, the membranes formed a pentalaminar structure (apposition), typical for the prefusion state. After apposition, sequential fusion of single alpha-granules took place and fusions of single or of compound granules with the plasmalemma were observed. The formation of a pore on the platelet surface allowed the passage of granular constituents to the exterior. The dense bodies extruded their electron-dense contents in a similar way after fusion with the plasmalemma but, compared with the alpha-granules, after less extensive swelling. These findings suggest that swelling of the secretory organelles plays an important role for granule fusion and platelet exocytosis. There is some evidence that the characteristic "internal contraction" of cytoskeletal structures in stimulated platelets is not the driving force of the platelet release reaction. An involvement of membranes of the surface connected system in the secretory pathway could not be ascertained.

Establishment, growth properties, and morphological characteristics of permanent human small cell lung cancer cell lines

Cell lines from SCLC were established with a success rate of 43% from different metastatic sites of treated and untreated patients. All 6 SCLC cell lines grew as floating cell aggregates without substrate adherence. The degree of aggregation ranged from very tight spheroids to very loose sheets and chains. This gross morphological property showed a striking correlation to the PDT, with short PDTs in loose growing cell lines and long PDTs in tight growing cell lines. Cell size and nuclear features, i.e., chromatin pattern and nucleolar prominence, also seemed to correlate with the PDT and gross morphology. All SCLC cell lines had dense core granules by electron microscopical examination. Several different serum-free and serum-supplemented growth media were tested for their feasibility in establishing and permanently growing SCLC. Serum-free SIT medium and SIT2.5 medium provided the best results in liquid culture. For semisolid SCLC cultivation, R 10 medium was superior to all other media tested. These cell lines are currently under intensive biochemical, molecular biological, and cytogenetical investigation in different laboratories and thus provide a tool for studying the biology of lung cancer.

Morphological predictors of survival in advanced gastric carcinoma univariate and multivariate analysis

In 76 curative resected advanced gastric carcinomas, the relationships between macro- and microscopy of the carcinoma and the survival rate were studied by univariate and multivariate survival analyses. In the Kaplan-Meier survival analysis (product limit estimator), significant influence on survival rate was found for tumor size, Laurén type, number of lymphocytes, tumor fibrosis, and N stage. In the multivariate survival analysis of covariates according to the Cox regression model, in macroscopically evaluable variables the tumor size was effective, in bioptically evaluable variables the number of plasma cells and the histological type. Concerning the primary tumor, the same set of variables presents significant correlations to survival time. Adding the involvement of lymph nodes, Laurén type, and N stage express all significant correlations of the tumor to survival rate. In parametric multivariate stepwise regression analyses of survival time, all variables working in the Cox proportional hazard model were very ineffective. But adaption of the Kaplan-Meier test to the effective variables of multivariate survival analysis elucidates the tight relationships between survival rate and these variables. No distinct relationships are present between variables of primary tumor and presence of lymph nodes metastases or N stage respectively.

Effects of intravenous nitroglycerin on ventricular ectopic beats in acute myocardial infarction

Ventricular premature beats (VPBs) in 21 consecutive patients with acute myocardial infarction (AMI) were continuously recorded on magnetic tape by means of an automatic arrhythmia monitor and counted manually. The patients were sequentially assigned to either a control (n = 11) or nitroglycerin group (n = 10). Both groups were comparable for age as well as for onset, localization, and extension of infarction. Recording in the control groups was begun at a mean of 9.3 hours following onset of infarction as obtained from patient history. This interval was 12.0 hours in the nitroglycerin group. At the start of therapy, the number of VPBs was identical in both groups. Ten patients received a mean of 2.1 mg of nitroglycerin per hour intravenously for 48 hours, whereas the control group received no specific therapy. The number of VPBs in the control group increased progressively until the sixth hour of registration and reached a maximum of 165% of the baseline value before subsequently declining. Nitroglycerin administration was associated with a significantly more rapid reduction in ventricular arrhythmias: 6 hours after onset of recording, the number of VPBs had declined to 39% of the baseline value (p less than 0.05 compared to control group). This study demonstrates that nitroglycerin reduces ventricular ectopic beats in the acute phase of myocardial infarction.

Acetylsalicylic acid in combination with dihydroergotamine for preventing thromboembolism

In a prospective randomized clinical trial involving 150 patients who underwent major abdominal surgery, acetylsalicylic acid (ASA) and dihydroergotamine (DHE) were examined either alone or in combination for their potential to prevent thromboembolism. Combined treatment with ASA and DHE was found to be more effective in preventing the spread of thrombi and their propagation to the femoral veins.

[The influence of glucocorticoids on the physiological cell renewal of gastric and intestinal mucosa (author's transl)]

The influence of Methylprednisolone (1.2 mg/kg body weight daily for 14 days) on the physiological cell renewal of gastric and intestinal mucosa was examined autoradiographically by determination of the 3H-labelling index and the cell cycle of the regenerating epithelial cells. Macroscopical or microscopical changes of the gastric or intestinal mucosa could not be observed. The labelling index was not significantly altered compared to the controls. Against this the determination of the cell cycle showed a clear inhibition of epithelial cell proliferation in all parts of the gastrointestinal tract with a prolongation of the postmitotic phase, a small inhibition of the DNA synthesis and a corresponding prolongation of the mean generation time.

Effect of prolonged infusion of maximal and supramaximal doses of pancreozymin on pancreatic enzyme secretion in the rat--exhaustion or inhibition?

Secretion of trypsin, chymotrypsin, lipase and amylase was measured in male rats under urethane anaesthesia using a method of continuous perfusion of the duodenum. Prolonged infusion of cholecystokinin-pancreozymin (CCK-PZ) over a period lasting 200-360 min was administered either alone or together with a submaximal dose of secretin (1 unit/100 g - 10 min). Infusion of CCK-PZ was carried out using maximal doses (1--1.5 unit/100 g - 10 min) with and without secretin. Supramaximal doses of CCK-PZ (2 and 4 units/100 g - 10 min) were used only in combination with secretin. In all experiments secretion of enzymes showed a triphasic pattern including an initial peak followed by a plateau secretion after 10--20 min (phase 1), a decreasing second phase and finally base-line secretion (phase 3), thus demonstrating exhaustion of enzyme output from the gland with time. With increasing and supramaximal dose of CCK-PZ the cumulative output of enzymes from start to baseline secretion decreased progressively. Under the same conditions the levels of peak and plateau secretion were lower, the duration of plateau secretion was longer and the decreasing phase of secretion was shortened. These features indicate inhibition of secretion with increasing supramaximal doses of CCK-PZ infusion. Whereas the proteolytic enzymes and lipase reacted in a parallel way always amylase secretion was sustained on a higher level, implicating an alternative pathway for secretion.

Runaway pacemaker. A serious and unresolved problem

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