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Biomedical subjects

P Gerhardt

Publications and source records attributed to P Gerhardt.

At least 109 records · Page 6Linked to original sources
PubMed1978

[Management of traumatic pelvic bleedings using embolization].

Massive retroperitoneal bleeding in pelvic trauma is a difficult problem in surgery, and surgical treatment is rarely attempted due to the risk involved. Angiographic embolization in this region is an uncomplicated and effective measure that may be performed without general anesthesia and simultaneous with shock treatment. Four patients with massive traumatic hemorrhage in the pelvic region were successfully treated with embolization.

Angiography↗
PubMed1978

[Indications and diagnostic value of computer tomography diagnosis of the abdomen].

The remarkable advantages of computerized tomography are graphic and numerical recording of very small differences in radiation absorption as well as presentation of the transverse body section. In the liver cysts, hematomas, abscesses and tumors larger than 2 cm in diameter can be diagnosed. To some extent differentiation between these lesions can be achieved by density measurements. Obstructive jaundice is another indication for computer tomography of the liver, the bile ducts and of the gall bladder. However, gall stones cannot be detected. The pancreas can be visualized in about 90% of all patients. Pseudocysts can be differentiated from inflammatory edema or tumors. The carcinoma of the pancreas does not differ in density from normal or inflammatory parenchyma. Therefore the diagnosis of carcinoma of the pancreas is still limited, although improvement has been achieved as well. The kidneys can be very well outlined on CT-images. Diagnostic assessment can be improved by application of contrast media. Recognition of cysts, urinary obstructions and tumors are possible with a high diagnostic reliability. Computerized tomography cannot replace the conventional diagnostic procedures; in the future the combination of several examinations will still be necessary.

Cysts↗
PubMed1978

[Computerized tomography and its significance in preoperative abdominal diagnosis].

Computerized tomography (CT) has considerably improved preoperative radiological diagnosis. Localization and extension of pathological findings are determined reliably with CT. Measurements of density in regions of interest enable a differential diagnosis. Moreover the questions about the advisability of surgery and the likehood of cure or palliation can be better answered by CT than by any other noninvasive procedure. With the use of CT in the abdominal region increasing indications for conventional radiological methods have decreased considerably. In this paper, some examples are given of CT diagnoses of the liver, the pancreas, the kidneys, and the retroperitoneal space. As the techniques involved are improved, computerized tomography is certain to replace conventional diagnosis methods.

Abdominal Neoplasms↗
PubMed1977

Ex vivo hemodialysis culture of microbial and mammalian cells.

A small hemodialysis culture unit was developed which can be attached to an arterial-venous shunt and worn by an animal for days. The unit consists of a blood channel separated by a membrane from a dialysate chamber in which microbial or mammalian cells can be cultured. Bacterial multiplication proceeded first exponentially at the maximal rate and then arithmetically at a lesser, dialysis-limited rate. In a survey of 16 pathogenic microorganisms and five types of mammalian cell, results indicated that most of the aerobes grew well, but none of the obligate anaerobes grew at all. The separation of the culture from cellular and macromolecular host defense mechanisms allowed the cultivation of parasitic cells on an animal that was not naturally susceptible.

Anaerobiosis↗
PubMed1977

Dialysis continuous process for ammonium-lactate fermentation of whey: mathematical model and computer simulation.

A mathematical model was developed to describe a dialysis process for the continuous fermentation of whey lactose to lactic acid, with neutralization to a constant pH by ammonia. In the process, whey of a relatively high concentration is fed into the fermentor circuit at a relatively low rate so that the residual concentration of lactose is low. The fermentor effluent contains ammonium lactate, bacterial cells, and residual whey solids and could be used as a nitrogen-enriched feedstuff for ruminant animals. Only water is fed into the dialysate circuit at a relatively high rate. The dialysate effluent contains purified ammonium lactate and could be converted to lactic acid and ammonium sulfate for industry. The fermentation was specifically modeled as a set of equations representing material balances and rate relationships in the two circuits. Dialysis continuous fermentations, in general, were modeled by combining these equations and by using dimensionless parameters. The generalized model was then solved for the steady state and used to simulate the specific fermentation on a digital computer. The results showed the effects of various material and operational and kinetic parameters on the process and predicted that it could be operated efficiently.

Journal Article↗
PubMed1977

Dialysis continuous process for ammonium-lactate fermentation of whey: experimental tests.

Laboratory experiments were conducted to validate theoretical predictions describing a dialysis continuous process for the fermentation of whey lactose to ammonium lactate, in which the fermentor contents are poised at a constant pH by adding ammonia solution and dialyzed through a membrane against water. Dried sweet-cheese whey was rehydrated to contain 230 mg of lactose per ml, supplemented with 8 mg of yeast extract per ml, charged into a 5-liter fermentor without sterilization, adjusted in pH (5.3) and temperature (44 degrees C), and inoculated with Lactobacillus bulgaricus. The fermentor and dialysate circuits were connected, and steady-state conditions were established. A series of such conditions was managed nonaseptically for 94 days to study the process and to demonstrate efficiency and productivity. As time progressed, the fermentation remained homofermentative and increased in conversion efficiency, although membrane fouling necessitated dialyzer cleaning about every 4 weeks. With a retention time of 19 h, 97% of the substrate was converted into products. Relative to nondialysis continuous or batch processes for the fermentation, the dialysis continuous process enabled the use of more concentrated substrate, was more efficient in the rate of substrate conversion, and additionally produced a second effluent of less concentrated but purer ammonium lactate.

Journal Article↗
PubMed1976

Fine structure of the Baccilus thuringiensis spore.

The thin-sectioned spore of Bacillus thuringiensis resembles that of Bacillus cereus in fine structure. Planar inclusions occur between the exosporium and spore coat and are structured differently from the parasporal crystal outside the exosporium.

Bacillus cereus↗
PubMed1976

Exteriorized carotid-jugular shunt for hemodialysis of the goat.

A surgical technique was developed for the establishment of a permanent exteriorized artificial shunt between a carotid artery and a jugular vein of a goat. The shunt allowed continuous hemodialysis with an artificial kidney for hours or a prosthetic unit for days and intermittent experimental use of the animal for months.

Animals↗