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The Fabry-Perot equation used to model asymmetric Fabry-Perot cavity reflection mode modulators can be considered as a bilinear transformation between the amplitude reflectivity of the modulator and the optical parameters of the cavity. Conformal mapping of this transformation into a suitable plane is used to visualise the operation of such a device working as a binary-phase modulator and to evaluate the tolerance of points of operation towards changes in the physical or operational parameters. Operation away from cavity resonance is shown to be less sensitive to parameter variations than conventional on-resonance operation.

Eine akute intraselläre Drucksteigerung ist eine lebensbedrohliche Komplikation beim Hypophysentumor. Plötzlicher Kopfschmerz, Ophthalmoplegie und rasch zunehmende Sehverschlechterung sind die klinischen Zeichen. Sie entstehen durch Infarkt und/oder Hämorrhagie in ein Adenom und verlangen rasche operative Entlastung. Je schneller die parasellären Strukturen dekomprimiert werden, desto besser sind die postoperativen Ergebnisse.

Abstract: A 76-year-old woman presented with an intrasellar and suprasellar mass which caused deterioration of visual acuity and bitemporal visual field defects. Trans-sphenoidal and transcranial partial resection revealed a primary chemodectoma. This tumour is very rare in the sellar area, where there are normally no paraganglionic cells. We review the literature and discuss possible mechanisms for the development of this tumour.

Summary This prospective open study of 124 patients [80% with completed stroke (CS), 16% with TIAS, 4% with PRIND] consecutively admitted between 1976 and 1981 investigates the rates of reinfarction after surgical treatment (extra-intracranial arterial bypass, EIAB and/or carotid thrombendarterectomy, TEA). 34% of patients had unilateral carotid stenosis, 26% unilateral internal carotid artery occlusion, 17% had occlusion of one and stenosis of the contralateral internal carotid artery, 14% bilateral carotid stenosis. Combined surgical morbidity and mortality was 5% after 158 operations in 124 patients; 7 of the 8 complications occurred in patients with CS.

Summary 32 cases of negative exploration in a joint follow-up series of 3,032 lumbar disc operations are described. Data from 15 hospitals were analyzed by means of questionnaires and computer-aided analysis. Detailed information is given about pre as well as intraoperative findings. The causes of negative lumbar disc exploration can be divided into two groups.

Summary Fibrin glue (Beriplast, Behring or Tissucol, Immuno) was used for 126 sublabial transseptal transsphenoidal operations in 119 patients from April 1981 to March 1987 in a variety of sellar pathologies together with septal bone and spongycel to seal the sellar floor and the anterior wall of the sphenoid sinus.

Summary A total number of 58 parameters (laboratory values, neurological symptoms, and vegetative parameters) were evaluated in 150 patients during the first seven days after severe head injury. The patients were divided into two groups, “survivors” and “non-survivors”. Eight easily evaluable routine parameters with the most significant differences between the two groups of patients were used for statistical evaluation of a “no survival chance score”. These highly indicative parameters are serum osmolarity and urea, blood glucose, total bilirubin, motor reaction to stimuli, body temperature, respiratory activity, and pupil reaction. A “low survival chance limit” was evaluated from each of these parameters by computer analysis. None of the patients in the series survived when three or more of these eight parameters had climbed beyond the limit. So far, the system is able to predict “no survival chances” in 50.8% of the non-survivors some six days prior to death; 80% of these predictions could be made by the fourth day after injury.