The effect of an acute rise in left atrial pressure on urine flow, urine specific gravity, and sodium excretion was studied in chronic preparations with and without anesthesia and at different hydration levels. Left atrial pressure was changed by an exteriorized purse string about the mitral annulus. In 56 of 58 experiments (including each of the above conditions) a transient increase of urine flow was found during atrial distention, accompanied by an increase in sodium excretion and a fall in urine specific gravity. Absolute volume and percentage increase of the diuresis varied directly with the degree of prehydration. Vasopressin infusions modified the response only in prehydrated animals. Arterial pressure and renal blood flow (electromagnetic flowmeter) were increased during atrial distention. At least two mechanisms interplay in the diuretic response: 1) hemodynamic and 2) humoral (ADH or Jahn's "diuretic factor"). The degree of prehydration seems to determine the threshold of the ADH mechanism. Our data speak against homeostatic fluid volume control by stretch receptors in the left atrium or its inflow tract.

Cerebral hemorrhage is a rare complication of the acquired immunodeficiency syndrome. We report a case of multifocal hemorrhage in a 37-year-old homosexual man with cerebral toxoplasmosis. Histopathologic examination, performed at cerebral autopsy, confirmed the findings on CT and MRI.

Summary. Hanford miniature pigs have been used as experimental animals in our laboratory for 5 years. Main object of the operative procedures, developped during this time, was the chronic implantation of catheters for injection and infusion or withdrawal of body fluids (blood, gastric juice, urine) without stress in unaesthetized animals. Thus a method for simultaneous catheterisation of a mesenterie vein and vena portae is described which allows besides the already mentioned possibilities the measuring of portal venous pressure and portal blood flow. Physiological data observed in these animals are reported.Key words: Miniature Pig --Housing --Catheter Implantations --Physiological Data.Zusammen/assung. Es wird fiber Erfahrungen berichtet, die in 5 Jahren an Hanford-Miniaturschweinen gesummelt wurden. Den Schwerpunkt der besehriebenen opcrativen Techniken bilden chronische Katheterimplantationen zur streBfreien Injektion oder Infusion und Materialentnahme (Blut, Magensaft, Urin) am wachen Tier. Unter anderem wird eine Methode zur simultanen Katheterisierung einer Mesenterialvene und der Pfortader beschrieben, die neben den oben erwiihnten MSglichkeiten Pfortaderdruck-und Pfortaderflowmessungen erlaubt. Daneben werden physiologisehe GrSgen, die an einer gr6geren Zahl yon Hanford-Miniaturschweinen gewonnen wurden, mitgeteilt.Schli~sselw6rter: Miniaturschwein --Haltung --Katheterimplantationen --Physiologische Normalwerte.Das Sehwein gewinnt als Versuehstier zunehmende Bedeu~ung in der experimentellen Medizin, da es sieh dureh die weitgehende ~bereinstim-mung seiner biologischen Daten mit denen des Mensehen fiir eine Vielfalt yon Untersuchungen besonders eignet. Diese 13bereinstimmung betrifft insbesondere Fettstoffwechsel, I-Ierz und Kreislaufsystem inklusive

No abstract

We describe a 77-year-old woman who developed a confusional state, cognitive impairment, behavioural abnormalities and dysphasia after treatment of hypercalcaemia. Repeated EEG recording revealed rhythmic sharp-wave activity over the right parietal-occipital lobe. Magnetic resonance imaging (MRI) showed marked hyperintense signal changes bilaterally. The diagnosis of a non-convulsive status epilepticus (NCSE) was made. With antiepileptic treatment the patient improved and MRI as well as EEG changes were almost all reversible. NCSE is an important differential diagnosis of patients with neuropsychiatric symptoms and can develop after rapid lowering of serum calcium levels in hypercalcaemia.

No abstract

"White coat" hypertension can be demonstrated in 20-25% of younger patients with mild-to-moderate hypertension. In a population of 50 untreated hypertensive patients > or = 70 years (mean age 79 +/- 6 years, office blood pressure > or = 160 mmHg systolic and > or = 95 mmHg diastolic) ambulatory blood pressure monitoring, ECG and echocardiography were performed to assess the frequency of "white coat" hypertension and the alerting reaction ("white coat" effect). "White coat" hypertension was diagnosed, if mean daytime ambulatory blood pressure was < or = 146/87 mmHg (taken as upper "normal" limit), "definite" hypertension, if > 146/87 mmHg. Nine patients (18%) were classified as "white coat", 28(56%) as "definite" hypertensives, 13(26%) as an "intermediate" group. There were no differences in gender, weight, concomitant diseases, pre-study treatment, and systolic or diastolic left ventricular function between the groups. Patients with "white coat" hypertension showed lower office blood pressure (178 +/- 13/98 +/- 3 vs 201 +/- 19/104 +/- 7 mmHg; p < 0.004), lower left ventricular mass index (131 +/- 9 vs 139 +/- 26 g/m2, p < 0.5), no left ventricular hypertrophy (ECG-criteria; p < 0.05), a more pronounced alerting reaction (39 +/- 13/22 +/- 5 vs 27 +/- 17/8 +/- 9; p < 0.01) and no correlation between office blood pressure and left ventricular mass compared to the "definite" hypertension group. The total group showed an average alerting reaction of 30 +/- 19/12 +/- 8 mmHg. It is concluded that "white coat" hypertension and an alerting reaction can be demonstrated in untreated elderly and very elderly hypertensive patients. Patients with "white coat" hypertension are characterized by a milder degree of hypertension, less cardiac target organ damage and a more pronounced alerting reaction. The prognostic significance of "white coat" hypertension in the elderly needs to be reevaluated in a larger population.

This study demonstrates for a Central European population older than 65 years the impact of hypertension as a risk factor for cardiovascular and cerebrovascular morbidity. To address the issue that risk of death showed no significant relationship to blood pressure, a longer follow-up period might be necessary.