Biomedical subjects
Publications and source records attributed to M Schemper.
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In Specimens of 115 patients with breast cancer 4 tumorparameters (tumorsize, tumorboder, nucleargrade, lymphocytic stromal reaction) 3 features of regional lymphnodes (sinushistiocytosis, T-cellreaction, lymphnode metastases) and estrogen and progesteron receptors were determined. A strong sinushistiocytosis and T-cellreaction could be verified mainly in metastases in free lymphnodes. The steroid receptor content does not correlate with histological parameters.
The determination of oestrogen receptors seems to be of prognostic value in the radically-operated breast cancer patient. Patients with negative receptor values exhibit early recurrence in a significantly higher percentage of cases than those with positive values. The prognostic implications of oestrogen receptor determination seem to be even higher than an assessment of axillary lymph node involvement. In metastatic breast carcinoma a correlation exists between response to hormonal therapy and receptor assay. The clinical implications for therapeutic management are discussed.
The influence of a continuous PGI 2 infusion on blood flow of various organs was tested in normovolemia and in hemorrhagic shock. PGI 2 increased the blood flow of stomach, pancreas and jejunum in normovolemic animals. The reduced blood flow due to hemorrhagic shock was increased to preshock values in stomach, pancreas, and jejunum. A linear correlation was found between the dose of PGI 2 and mucosal blood flow of the stomach.
Thoracic endoscopic sympathectomy (TES) is a short surgical procedure used for the treatment of palmar and axillary hyperhidrosis. It involves pneumothorax, the lateral and head up position, and necessitates minimal chest excursions during breathing, so that a special type of anaesthesia is required. In 13 patients two different methods were compared and blood gas analysis as well as circulatory parameters were studied. We therefore propose an anaesthetic method using controlled mechanical ventilation; relaxation; intravenous anaesthesia; at least 1 1 fluid replacement; and careful monitoring.
175 patients with metastatic breast cancer, treated with chemotherapy, were analyzed retrospectively to identify the characteristics of prognostic importance in predicting response to chemotherapy and survival from onset of the chemotherapy. The most significant factors were the sites of metastatic disease and an estimate of the total extent of disease.
An agar gel electrophoresis was performed to demonstrate various amounts of estrogen receptors of three different topics in 38 mammary carcinomas. A good correlation between estrogen receptors in primary mammary carcinomas and axillary lymph node metastases could be found.
In 50 primary cancers of the mammary gland, tissue samples from three different parts of each tumor were analyzed for estrogen content by agar gel electrophoresis. In 12 tumors receptor-rich and receptor-poor zones were detected within the tumor for the 4-s fraction, and in 11 tumors for the 8-s fraction. Confidence limits (99%) indicate that these findings might range from 10.4% to 42.5% for the 4-s fraction, and 10.2%-44.1% for the 8-s fraction.
The analysis of prognostic factor studies by Cox or logistic regression models is often impeded by missing covariate values. In 1990 Schemper and Smith recommended a conditional probability imputation technique (PIT) for the analysis of treatment studies which can be easily applied using standard software and which has been demonstrated to outperform the complete case and omission of covariates strategies. Recent research, however, showed that PIT cannot universally be recommended and it was concluded that model-based methods should be preferred. We agree with these conclusions but also think that there is enough empirical evidence to judge the performance of PIT to be satisfactory in typical prognostic factor studies. Furthermore, comparisons of PIT with multiple imputation in the same context did not indicate an advantage of the latter more involved technique. By means of an analysis of a prostate cancer data set various aspects of application of PIT are discussed, in particular that PIT permits direct comparability of marginal and partial effects analyses. We conclude that PIT continues to be an appropriate and attractive choice for analyses of prognostic factor studies.
A clinical series has been analysed to determine which of two similar, extrathoracic "extraanatomic" methods of treating proximal blocks of the subclavian artery is the superior option. From 1975 until 1988 direct carotid-subclavian anastomosis was used in 32 patients and carotid-subclavian bypass in 19. There were no statistically significant differences for the probability of postoperative survival (p less than 0.877 Breslow; p less than 0.774 Mantel), intraoperative blood loss or the duration of anaesthesia. Those patients who had undergone subclavian artery repair had a significantly longer survival than those following carotid bifurcation endarterectomy (p less than 0.002 Breslow, p less than 0.0002 Mantel). As patients with subclavian lesions have a reasonable life-expectancy, they may possibly experience late complications of their vascular repair. Therefore it seems important to select the most durable operation, and direct carotid subclavian anastomosis has a significantly greater patency rate than bypass (p less than 0.006 Breslow, p less than 0.006 Mantel). Patients with preoperative symptoms of cerebrovascular insufficiency had a lower probability of survival than those with upper extremity claudication, although this did not reach statistical significance (p less than 0.205 Breslow; p less than 0.198 Mantel).
A randomized prospective study comparing PTFE-Y and Dacron-Y-grafts with regard to function rate, morphology, hemodynamic differences along the proximal anastomosis and body of the graft, complications and quality of material was performed. Between March 1983 and February 1987, 112 patients were admitted to the study. Randomization including the criteria of age, sex, indication to operation (chronic occlusive disease, aneurysm) run-off, diabetes, nicotine consumption and operative approach (transperitoneal, retroextraperitoneal) followed the methods of adaptive randomization developed by Pocock and Simon and was well balanced. Function rate and complications as well as morphological alterations showed no significant differences in either group. During a mean observation period of 24 months, Group I yielded a 97% and Group II a 95% function rate (Kaplan-Meier). In all patients but one in each group with limb graft occlusions (n = 5) function was regained by successful thrombectomy and profundaplasty. With respect to Doppler ultrasound differences in flow pattern, in four patients with enlarged proximal side-end anastomosis and adequate--not to large--incision is recommended performing the proximal anastomosis.