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K Wassermann

Publications and source records attributed to K Wassermann.

98 records · Page 6Linked to original sources
PubMed1983

Dopamine produces vasodilation in specific regions and layers of the rabbit gastrointestinal tract.

The effect of intravenous dopamine infusion (25 and 60 micrograms per kg and min consecutively) on blood flow distribution in the splanchnic region of anesthetized rabbits was studied applying the microsphere technique. During infusion of the low dose, blood flow increased most markedly in the stomach, less in the pancreas, jejunum and descending colon, and decreased in the spleen. In the stomach the increase was confined to the mucosa-submucosa. Raising the dose of dopamine resulted in a slight fall of arterial blood pressure, a further increase in blood flow through the mucosa-submucosa of the gastric fundus (+493 % as against control), but not through the other tissues studied. In another series, blood flow through the left gastric artery was measured with an electromagnetic flowmeter. The infusion of dopamine produced a dose-dependent increase in regional blood flow, which was inhibited by the dopamine antagonist bulbocapnine. Furthermore, the control blood flow was transiently decreased, and resistance to flow was increased by bulbocapnine. The results indicate that the dopamine-induced vasodilation in the gastrointestinal tract of the rabbit is largely restricted to the gastric circulation and suggest that specific receptors mediating this vasodilation are located in the mucosa-submucosa. It is hypothesized that endogenous dopamine functions as a vasodilatory tissue hormone in the gastric mucosa of the rabbit.

Animals↗
PubMed1983

Blood flow redistribution by dopamine in the feline gastrointestinal tract.

The effect of intravenous infusion of dopamine (10 and 25 micrograms X kg-1 X min-1 consecutively) on visceral blood flow distribution was examined in anesthetized cats using the microsphere technique and electromagnetic flowmetry. Arterial blood pressure did not change in response to dopamine infusion, but blood flow through the superior mesenteric artery, and blood flow in the mucosa-submucosa of the gastric antrum and various gut segments increased significantly. During infusion of the high dose the increase was most marked in the mucosa-submucosa of the antrum (+355%) and distal colon (+371%). By contrast, blood flow decreased in the muscularis-serosa of the gut segments investigated, in the spleen, pancreas, and the hepatic arterial bed. The increase in blood flow through the superior mesenteric artery was blocked by the dopamine antagonist bulbocapnine (10 mg/kg i.v.). The results suggest that the receptors mediating the dopamine-induced vasodilation in the gastrointestinal tract are located in the resistance vessels of the mucosa-submucosa.

Animals↗
PubMed1980

Dopamine-induced diuresis in the cat without changes in renal hemodynamics.

The effects of intravenous (i.v.) and intraarterial (i.a.) injection and infusion of dopamine (DA) on renal hemodynamics, regional sympathetic activity and kidney function were investigated in anaesthetized cats. In response to the i.v. bolus injection of DA (25 microgram/kg), mean arterial blood pressure (MABP) was increased by 19.7%, renal blood flow (RBF) by 16.6%, and regional sympathetic discharges were inhibited. The principal effect of i.a. bolus injection of DA into the renal artery was vasoconstriction. Vasodilation was observed neither after lower doses of DA nor after pretreatment with phenoxybenzamine. During continuous i.v. infusion of 10 microgram DA kg-1 min-1 MABP, RBF, renal sympathetic discharges and glomerular filtration rate (GFR) did not change, whereas urine volume was increased by 120.5%, sodium excretion by 99.7%, chloride excretion by 143.2%, and potassium excretion by 31.9%. Urine osmolality was decreased and osmolal clearance increased. Raising the DA dose to 25 microgram kg-1 min-1 resulted in a fall of GFR, but the diuretic response was not significantly different from that of the low dose. Bulbocapnine (6 mg/kg i.v.) antagonized the DA-induced diuresis. In conclusion, the diuretic effect of DA in the cat is not dependent on a change in RBF, GFR or renal sympathetic activity. This suggests that a tubular site of action is primarily responsible for DA diuresis.

Animals↗
PubMedDate not supplied

Morphogenesis in chronic Pneumocystis carinii infection--discussion of three cases.

The clinical and histological features of three HIV1-positive patients are reported of whom two showed persistent focal lesions on serial chest X-rays without any demonstrable lesion on repeated bronchoscopies. The third patient presented with recurrent pneumothorax. By thoracoscopy peripheral lung tissue was obtained in all cases, showing localized histomorphological findings compatible with a prolonged interstitial reaction around Pneumocystis carinii (PC) organisms and their breakdown products. Based on the finding of foreign body granulomas and an increased number of alveolar macrophages, we propose a hypothetical pathway for the development of this unusual reaction to PC infection focusing on the possible secretion of tumor necrosis factor alpha by activated macrophages. By this model the unusual features of PC infection in our patients and in the literature could be explained. Furthermore, in these cases possibly an additional oral or intravenous treatment might be indicated.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

Non-specific interstitial pneumonia (NIP): immunohistologic screening of etiologic agents.

Non-specific interstitial pneumonia (NIP) occurs frequently in patients with HIV-infection. To elucidate the etiology of this pulmonary disorder, we searched for 13 different microorganisms in transbronchial biopsies from 15 patients with NIP, 15 patients with Pneumocystis carinii pneumonia (PCP) and 20 patients with lung diseases not related to HIV-infection using monoclonal antibodies and the APAAP- or PAP-technique for immunostaining. Chlamydia trachomatis and parainfluenza III were detected frequently and in great number. Adenovirus, influenza B, varicella zoster and cytomegalovirus were also found frequently, but not in great number. Measles virus, respiratory syncytial virus, influenza A and herpesviruses 1&2 were not found. Also not found were parainfluenza I, mycoplasma pneumoniae and coronavirus. In seven out of fifteen NIP patients at least one organism was shown, compared to nine out of fifteen patients with PCP and eight out of twenty patients in the control group.

AIDS-Related Opportunistic Infections↗