Human Aldehyde Dehydrogenase: Kinetic Identification of the Isozyme for Which Biogenic Aldehydes and Acetaldehyde Compete

Michaelis constants and maximal velocities for phenylacetaldehyde (a metabolite of phenylethylamine), 3,4-dihydroxyphenylacetaldehyde (a metabolite of dopamine), 5-hydroxyindole acetaldehyde (a metabolite of serotonin), and 3,4-dihydroxyphenylglycolaldehyde (a metabolite of epinephrine and norepinephrine) have been determined for both cytoplasmic (E1) and mitochondrial (E2) isozymes of human liver aldehyde dehydrogenase (EC 1.2.1.3). Kinetic constants with biogenic aldehydes have never been previously determined for individual homogeneous isozymes of aldehyde dehydrogenase from any species. Mathematical treatment of these constants suggests that competition with acetaldehyde during alcohol metabolism would severely inhibit dehydrogenation of biogenic aldehydes with the mitochondrial and not the cytoplasmic isozyme of human liver aldehyde dehydrogenase.     

A new after-care model in geriatrics

78 geriatric patients predominantly suffering from cardiocerebrovascular diseases (stroke, heart insufficiency) and lesions respectively operations of the locomotion system (fractures, arthroses) were admitted in 1987 from acute hospitals for after-treatment (short-term care). 35 (= 45%) of them (average age 80 (61-92) could be discharged after 63.5 days on average, 11 died from intercurrent complications, 9 remained for long-term care as inrehabilitable. Besides other concomiting troubles mainly cardiac and circulation affections were present in the majority of patients. Their identification (a. o. by means of ultrasonic methods) and therapy also means a secondary prevention of cerebral as well as of fall and injuries inducing risk factors. The results confirm the principal rehabilitation chance of multimorbid geriatric patients by use of the diagnostic and therapeutic special potential of geriatrics.     

Dose-Additive Inhibition of Intake of Ethanol by Cholecystokinin and Bombesin

Cholecystokinin (CCK) and bombesin (BBS) are neuropeptides of the brain and gut which have been shown to inhibit intake of ethanol. CCK octapeptide and BBS tetradecapeptide were injected intraperitoneally in both single doses and combinations of doses to determine interactions of the two peptides in the control of consumption of ethanol. Water-deprived rats were given access to 5% w/v ethanol for 30 min, followed by a 30-min access to water, daily. One minute before presentation of ethanol, rats were injected with either saline or one of ten peptide solutions (three of CCK alone, three of BBS alone, and four combinations of both). Results from the injections of single peptides were used to determine predicted inhibitions of the peptide combinations, assuming perfect additivity of doses. None of the actual values of inhibition of intake of ethanol by peptide combinations differed significantly from its predicted additive value. Endogenous CCK-like and BBS-like peptides may suppress intake of ethanol by an additive mechanism of inhibition.     

Treatment of instrumental perforation of esophageal malignancy by transhiatal esophagectomy

Perforation of esophageal malignancy secondary to instrumentation is an uncommon but catastrophic complication. Esophageal perforation at the site of an obstructing esophageal malignancy precludes simple operative repair and mandates esophageal resection with reestablishment of gastro-intestinal tract continuity. In the past the standard surgical approach has involved transthoracic esophageal resection via thoracotomy. We have successfully treated four patients with perforated esophageal neoplasms by transhiatal esophagectomy and cervical esophagogastrostomy, thus avoiding thoracotomy in high-risk patients. We consider transhiatal esophagectomy an advantageous alternative in the management of selected cases of instrumental esophageal perforation adjacent to an esophageal malignancy.     

Effect of hemodilution on brain tissue during global ischemia

This study evaluates the effect of blood volume and hematocrit changes on brain tissue during temporary global ischemia. Normal saline was administered intravenously to 55 gerbils to achieve hypo-, normo-, and hypervolemic hemodilution and uniform 30% hematocrit reduction. Each group had unilateral carotid artery ligation and temporary (20 minute) contralateral carotid occlusion. After ten days or death, brains were harvested, preserved in formalin, sectioned in a manner which provided adequate samples of both cortex and hippocampus, and stained with H&E and luxol fast blue. They were then examined and staged microscopically for white and gray matter infarction, edema, and neuronal injury and loss. Histologic studies were performed in a randomized and blinded manner and were classified by one of four categories: normal, minimal, moderate, and severe changes. Three of ten (30%) controls survived ten days but had severe neuronal loss, minimal cerebral edema and a minimal to moderate number of white matter strokes. Survival was best in animals treated with hypovolemic hemodilution (43%). Other rates were: normovolemic (33%), controls (30%), and hypervolemic (8.3%). The degree of brain tissue damage was markedly less in the normovolemic group. In this model, normovolemic hemodilution followed by hypovolemic hemodilution offered the best overall cerebral protection during global ischemia.     

Use of percutaneous silastic central venous catheters in neonates and the management of infectious complications.

A prospective study of 35 patients in the neonatal intensive care unit was conducted to examine the safety and feasibility of percutaneous Silastic central venous catheters for the provision of prolonged parenteral alimentation. Particular attention was directed to the possibility of maintaining these lines through intercurrent episodes of infection. Catheters were placed in 34 infants (97%). At the time of insertion, 21 patients (62%) weighed less than 1000 gm and 13 patients (38%) weighed less than 750 gm. The average duration of catheterization was 32.0 +/- 18.2 (SD) days; 19 patients (56%) had lines in place for more than 30 days. Mechanical difficulties complicated the course of five patients (15%). Four cases of bacteremia were identified; this represents 3.7 infections/1000 days of catheter use. All infections were caused by methicillin-resistant staphylococci. Two patients required catheter removal to clear their infection, but in two of the four bacteremic patients, the infection was cleared and the line was sterilized by the administration of antibiotic therapy through the central catheter. We conclude that Silastic central venous catheters can be used safely to deliver intravenous nutrition to extremely small preterm infants over a prolonged period of time, and in carefully selected patients, successful treatment of complicating infections may be achieved without catheter removal.