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Biomedical subjects

P Gerhardt

Publications and source records attributed to P Gerhardt.

At least 91 records · Page 5Linked to original sources
PubMed1983

[Value of vascular morphology for the selection of catheters in selective celiacography and mesentericography].

By means of 192 lateral aortograms the vascular morphology of the coeliac and superior mesenteric artery were correlated to age, sex and body weight. Independently of these parameters 90% of the exit angles of the coeliac artery were situated between 15 degrees and 90 degrees with a median of 45 degrees. In persons with less than 65 kg body weight the median origin angle of the superior mesenteric artery corresponded to 45 degrees, too, whereas in heavier patients they were bigger (60 degrees). The vascular diameter and the further course of the superior mesenteric artery significantly depended on the constitutional type. In 40.5% we saw a cranial eccentric stenosis of the coeliac artery. Frequency and intensity were not influenced by age, sex or body weight, but accompanied by smaller origin angles of the coeliac artery and bigger ones of the superior mesenteric artery. In conclusion different catheter shapes in dependence of the constitutional type are recommended for combined coeliac and mesenteric angiography.

Anthropometry↗
PubMed1982

[Fibrinolytic therapy of lower limb deep vein thrombosis with urokinase (author's transl)].

In 81 patients with deep vein thrombosis of the lower limb, urokinase therapy was performed in combination with heparin according to a new regimen at higher dosages. When urokinase was administered at an initial maintenance dosage of 1,000-2,000 IU/kg/h (loading dose 150,000-250,000 IU), phlebographically documented complete or partial recanalization could be observed in 68% of the cases. The higher dosage schedule induced a more pronounced deobliteration especially in treatment of iliac vein thromboses (67% recanalization) in comparison to the lower dosage regimen (only 43% recanalization). Nearly comparable therapeutic results could be achieved in therapy of popliteal or saphenous vein thromboses. The data suggest that the higher dosage schedule examined here is indicated in treatment of extensive and large volume thromboses. The dosage of urokinase was further adjusted to attain a reduction of fibrinogen to 50-100 mg/dl. The concentration should not fall below 50 mg/dl. Therapy with urokinase proved practicable. Serious side effects did not occur. 8.6% of the patients showed hematuria and 6% a decrease of the Hb by more than 2 g/dl. The high proportion of older thromboses and the only low rate of recanalization (23%) in these cases suggest the necessity of an early commencement of fibrinolyses in therapy of deep vein thrombosis.

Anticoagulants↗
PubMed1982

[Bases, technic and expressiveness of computer tomography. Indications and efficiency].

The developments of reconstruction mathematics, computer technology and X-ray detectors were prerequisite to the invention of computer tomography. Essential progress was made leading to the development of the currently used third and fourth generation scanners. The use of CT has greatly influenced diagnostic imaging and therapy planning. The main advantages of CT are the demonstration of the third dimension, the differentiation of very minor density differences and non-invasiveness. In spite of the high costs of CT equipment and maintenance, an overall reduction of cost was achieved by decreasing the number of diagnostic procedures and reducing the time between the beginning of illness and therapy.

Humans↗
PubMed1982

[Flow measurements in the major visceral arteries (author's transl)].

Arterial flow was measured by the spill-over technique in 202 coeliac arteries and 158 superior mesenteric arteries during the course of visceral angiography in 250 patients. In the coeliac artery a mean value of 15.8 +/- 4.3 ml/sec was obtained, flow in the super mesenteric artery was significantly less at 12.1 +/- 3.4 ml/sec. The wide variation from 4 to 26 ml/sec in the coeliac artery was remarkable, as well as flows from six to 20 ml/sec in the superior mesenteric artery.

Blood Flow Velocity↗
PubMed1982

Wet and dry bacterial spore densities determined by buoyant sedimentation.

The wet densities of various types of dormant bacterial spores and reference particles were determined by centrifugal buoyant sedimentation in density gradient solutions of three commercial media of high chemical density. With Metrizamide or Renografin, the wet density values for the spores and permeable Sephadex beads were higher than those obtained by a reference direct mass method, and some spore populations were separated into several density bands. With Percoll, all of the wet density values were about the same as those obtained by the direct mass method, and only single density bands resulted. The differences were due to the partial permeation of Metrizamide and Renografin, but not Percoll, into the spores and the permeable Sephadex beads. Consequently, the wet density of the entire spore was accurately represented only by the values obtained with the Percoll gradient and the direct mass method. The dry densities of the spores and particles were determined by gravity buoyant sedimentation in a gradient of two organic solvents, one of high and the other of low chemical density. All of the dry density values obtained by this method were about the same as those obtained by the direct mass method.

Bacillus cereus↗
PubMed1982

Photometric immersion refractometry of bacterial spores.

Photometric immersion refractometry was used to determine the average apparent refractive index (n) of five types of dormant Bacillus spores representing a 600-fold range in moist-heat resistance determined as a D100 value. The n of a spore type increased as the molecular size of various immersion solutes decreased. For comparison of the spore types, the n of the entire spore and of the isolated integument was determined by use of bovine serum albumin, which is excluded from permeating into them. The n of the sporoplast (the structures bounded by the outer pericortex membrane) was determined by use of glucose, which was shown to permeate into the spore only as deeply as the pericortex membrane. Among the various spore types, an exponential increase in the heat resistance correlated with the n of the entire spore and of the sporoplast, but not of the isolated perisporoplast integument. Correlation of the n with the solids content of the entire spore provided a method of experimentally obtaining the refractive index increment (dn/dc), which was constant for the various spore types and enables the calculation of solids and water content from an n. Altogether, the results showed that the total water content is distributed unequally within the dormant spore, with less water in the sporoplast than in the perisporoplast integument, and that the sporoplast becomes more refractile and therefore more dehydrated as the heat resistance becomes greater among the various spore types.

Bacillus cereus↗
PubMed1982

Bacterial spore heat resistance correlated with water content, wet density, and protoplast/sporoplast volume ratio.

Five types of dormant Bacillus spores, between and within species, were selected representing a 600-fold range in moist-heat resistance determined as a D100 value. The wet and dry density and the solids and water content of the entire spore and isolated integument of each type were determined directly from gram masses of material, with correction for interstitial water. The ratio between the volume occupied by the protoplast (the structures bounded by the inner pericytoplasm membrane) and the volume occupied by the sporoplast (the structures bounded by the outer pericortex membrane) was calculated from measurements made on electron micrographs of medially thin-sectioned spores. Among the various spore types, an exponential increase in the heat resistance correlated directly with the wet density and inversely with the water content and with the protoplast/sporoplast volume ratio. Altogether with results supported a hypothesis that the extent of heat resistance is based in whole or in part on the extent of dehydration and diminution of the protoplast in the dormant spore, without implications about physiological mechanisms for attaining this state.

Bacillus cereus↗
PubMed1982

Detection of neoplastic lymph node involvement in the retroperitoneal space. Diagnostic value of CT, echography and lymphography.

The diagnostic value of echography, computerized tomography and lymphography in the detection of infiltrating retroperitoneal lymph nodes was assessed in a prospective study. Ninety-six patients suffering from Hodgkin's disease, non-Hodgkin lymphoma, seminomatous and and non-seminomatous tumours of the testis were examined with all three methods. Sixty-two (30 non-seminomas, 32 Hodgkin's diseases) had an exploratory laparotomy at least one week after the diagnostic examinations. Sensitivity and specificity were assessed on the basis of the pathohistological findings. The sensitivity was 92% for CT, 79% for echography and 83% for lymphography. The specificity was 89% for CT, 95% for echography and 84% for lymphography. The presented findings suggest that a re-evaluation of the diagnostic strategy in assessment of lesions involving retroperitoneal lymph node is required.

Humans↗
PubMed1981

Urokinase therapy of subclavian-axillary vein thrombosis.

In 18 cases with primary subclavian-axillary vein thrombosis fibrinolytic therapy was performed with urokinase in combination with heparin. The thrombolytic efficacy clearly depended on the thrombus age and the dose of urokinase applied. Under treatment with a median initial maintenance dosage of urokinase of 1,000-2,000 IU/kg/h (loading dose 150,000-250,000 IU urokinase) in combination with heparin (15-17 U kg/h) in mine of 11 patients (82%) with recently developed (8 days or less) thrombosis, a nearly complete deobliteration of the venous system was observed. In the case with thrombosis of more than 10 days no alteration of the venous occlusions could be seen. Relevant side effects did not occur. Our results emphasize urokinase therapy of acute subclavian-axillary vein thrombosis and permit general inferences concerning the efficacy and the dosage requirements of the thrombolytic substance urokinase.

Adolescent↗
PubMed1981

[Pre- and postoperative ultrasonography of portal circulation in portal hypertension in childhood (author's transl)].

The use of ultrasound investigation in children with portal hypertension is discussed and a 14 year old patient is presented. With this non-invasive investigation, the course, diameter and patency of the splenic vein can be demonstrated, repeated post-operative investigations showed a reduction in the size of the splenic vein of at least 2 mm. following patent spleno-renal anastomosis. The ultrasound technique is demonstrated.

Adolescent↗
PubMed1980

A computed tomographic prolective trohoc study of chronic schizophrenics.

The maximal width of the third ventricle, the maximal distance between the outer tips of the anterior horns, and the number of enlarged cerebral sulci on the two highest CT slices were measured in 68 chronic schizophrenic patients on cranial computed tomograms in order to detect a possible enlargement of the cerebrospinal fluid (CSF) filled intracranial spaces. These results were compared with values obtained from a control group which was formed in accordance with definite exclusion criteria and matched-pair parameters (sex, age and maximal inner diameter of the skull). In a prolective trohoc study no difference was found in the size of the CSF spaces of schizophrenics and the controls. The psychopathological condition of the patients, which was classified in a semistandardized dialogue, also showed no correlation with the ventricular size or the number of enlarged cerebral sulci.

Adult↗
PubMed1979

Dialysis continuous process for ammonium-lactate fermentation: improved mathematical model and use of deproteinized whey.

Separate terms for substrate limitation and product inhibition were incorporated into an equation describing the rate of cell growth for the steady-state fermentation of lactose to lactic acid with neutralization to a constant pH by ammonia. The equation was incorporated into a generalized mathematical model of a dialysis continuous process for the fermentation, developed previously, in which the substrate is fed into the fermentor and the fermentor contents are dialyzed through a membrane against water. The improved model was used to simulate the fermentation on a digital computer, and the results agreed with previous experimental tests using whole whey as the substrate. Further simulations were then made to guide experimental tests using deproteinized whey as the substrate. Dried cheese-whey ultrafiltrate was rehydrated with tap water to contain 242 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 (5.5) and temperature (44 degrees C), and inoculated with an adapted culture of Lactobacillus bulgaricus. The fermentor and dialysate circuits were connected, and a series of steady-state conditions was managed nonaseptically for 71 days. The fermentation of deproteinized whey relative to whole whey, with both highly concentrated, resulted in similar extents of product accumulation but at a lesser rate.

Journal Article↗