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Biomedical subjects

C Krebs

Publications and source records attributed to C Krebs.

At least 55 records · Page 3Linked to original sources
PubMed1986

Pharmacokinetics of the bipyridines amrinone and milrinone.

The pharmacokinetics of milrinone were studied in sequential ascending doses in New York Heart Association Class III and IV patients receiving oral and intravenous medication. The parameters determined after parenteral administration were estimated by fitting the plasma concentration data to an open two-compartment body model. After oral medication, regression-independent parameters were determined. After either oral or parenteral administration of milrinone, plasma levels were dose dependent and the drug had an apparent first-order terminal elimination half-life of approximately 2 hr. The apparent volume of distribution was approximately 400 to 500 ml/kg, and total body clearance was approximately 130 ml/kg/hr. These values obtained in patients receiving milrinone were compared with those obtained for milrinone in volunteers, as well as those noted with the other inotropic bipyridine, amrinone. Milrinone's elimination from the blood stream patients was slower that that in normal healthy subjects and faster than amrinone's elimination in patients with congestive heart failure. Milrinone's pharmacokinetic parameters in these patients were unchanged after approximately 30 days of continuous oral medication.

Administration, Oral↗
PubMed1984

Inflammatory bowel disease in childhood--treatment and follow up.

This study is based on 150 patients whose first symptoms of inflammatory bowel disease (IBD) appeared before puberty between 1955 and 1979. Recurrence of disease after improvement on medical treatment occurred within a shorter time in Crohn's disease than in ulcerative colitis. In this series it was twice as probable for surgery to be required within the first five years of illness for a child with Crohn's disease than for a child with ulcerative colitis. Median relapse time after medical treatment was 11 months for ulcerative colitis and 15 months for Crohn's disease, and the median relapse time after surgical treatment (including "incomplete" procedures) was over seven years for ulcerative colitis and just under five years for Crohn's disease. In ulcerative colitis it is suggested that earlier surgery might save the patient a period of distressing symptoms and reduce the risk of recurrence.

Adolescent↗
PubMed1984

Calcium ionophore A-23187 and 12-O-tetradecanoyl-phorbol-13-acetate stimulation of prostaglandin synthesis in herpes simplex virus type 2-transformed rat cells.

The purpose of this investigation was to determine whether cells transformed by herpes simplex virus type 2 (HSV-2) can be stimulated to synthesize prostaglandins (PG). Stimulation was determined by measuring the release of PG into overlay fluids from cell monolayers prelabeled with [3H]arachidonic acid. Results showed that Ca2+ ionophore A-23187 markedly stimulated arachidonic acid release starting 30 min after treatment of HSV-2-transformed and nontransformed rat embryo fibroblast cells. However, only HSV-2-transformed cells were stimulated in production of PG. HSV-2-transformed, nontumorigenic, rat embryo fibroblast, line G, clone 2.0 cells synthesize nearly equal amounts of prostaglandin E2 (PGE2) and prostaglandin F2 alpha, while tumor (rat fibrosarcoma) cells synthesize primarily PGE2. Stimulation of PGE2 synthesis by Ca2+ ionophore A-23187 or 12-O-tetradecanoyl-phorbol-13-acetate decreased as rat fibrosarcoma cells were serially passaged in tissue culture. At low passage of parental rat fibrosarcoma cells, four distinct morphological clonal cell lines were isolated, which varied markedly in their capacity to be stimulated in PG synthesis by 12-O-tetradecanoyl-phorbol-13-acetate. There was correlation between the capacity of clone 1 cells to be stimulated in PGE2 synthesis by serum alone and capacity of the tumors produced by the clone 1 cells to metastasize to the lungs of syngeneic tumor-bearing rats. In summary, cell transformation by HSV-2 appears to be essential for stimulation of PG synthesis in cells. The capacity to be stimulated in arachidonic acid metabolism and PG synthesis may be important in the process of carcinogenesis by a putative human cancer virus.

Animals↗
PubMed1983

Inflammatory bowel disease in childhood. Presentation and diagnosis.

150 patients whose first symptoms of inflammatory bowel disease (IBD) presented before puberty were seen at this hospital between 1955 and 1979. Ulcerative colitis with the rectum less severely involved than the colon was commoner than usually reported in adults. Colectomy with ileorectal anastomosis allowed these children to go through school life and adolescence without an ileostomy. Failure of medical treatment was much commoner in those presenting with already total colonic involvement. Children with Crohn's disease were twice as likely to come to surgery within the first five years of illness than those with ulcerative colitis. Delayed diagnosis (mean 2.6 years) was much greater in Crohn's disease, especially in the 25% presenting initially with failure to thrive and no specifically alimentary symptoms.

Adolescent↗
PubMed1981

[Animal experiments concerning the autoimplantation of splenic tissue (author's transl)].

15 male rabbits were divided into three groups. The animals in group 1 were splenectomized. In group 2 pulpa tissue from the cut surface of the spleen was left in the abdominal cavity. Group 3 was sham operated. After 15 months all animals from group 2 showed particles of histologically intact splenic tissue mainly on the parietal peritoneum of the abdominal wall. The implications of the autoimplantation of splenic tissue during splenectomy are discussed.

Animals↗
PubMed1979

[Surgical technic to alleviate anal incontinence using a magnetic anal closure].

Available operative procedures to reduce incontinence are gracilis transplant, levator plastic, free muscle transplantation and pacemakers. Further procedures being tested in clinical trials are electronic cuffs, modified Scott's sphincters, and implantation of cuffs of unstriated muscle. The magnetic anal ring, which has been developed in Erlangen, consists of two halves. Using a sacral approach both parts can be placed around the rectum without opening the bowels. An anal tampon consisting of a magnetic tampon and a tampon covering is responsible for occlusion. The tampon covering consists of polyvinylformalfoam, which guarantees an excellent plugging. Application is similar to tampons for menstruation; tampons can be changed three times a day and the bowel can be emptied normally when a change is made. In order to work successfully the tampon is pressure adapted to the pressure profile of the large bowel. Histologic investigations of the mucosa did not show any alterations. Megacolon or megarectum proximal to the anal ring did not occur.

Anal Canal↗
PubMed1978

Intraoperative endoscopy in oesophageal atresia and anorectal anomalies.

In four children with oesophageal atresia and two children with high anorectal anomalies a magnetic bougienage respectively a magnetic pull-through procedure have been performed. In all cases the cylinders have been placed under endoscopic control. The endoscopic intraoperative procedure has proved to be very useful in these 6 cases. Having performed a successful bougienage the cylinder of the upper segment can pass distal to the thread in the stomach and can then be grasped with a flexible endoscope via gastrostomy. Endoscopy after magnetic pull-through procedure in anorectal anomalies is necessary in order to control the newly created pathway together with manometry and x-ray studies.

Anal Canal↗
PubMed1975

[Diagnosis and surgical treatment of bronchial carcinoma - a report on 1000 cases (author's transl)].

One thousand cases of bronchial carcinoma, which had been treated in the Chirurgische Universitätsklinik Erlangen in 17 years, are reported. 63,2% were either primarily inoperable or found to be so after an exploratory laparotomy; Only 32,4% of all patients were admitted in the first 3 months, 17,6% after more than 12 months, Squamous epithelial carcinoma was the most frequent histological type (51,2%), then came small cell carcinoma (16,4%), dedifferentiated carcinoma (5,1%) and adenocarcinoma (4,1%). The best results of operative treatment were obtained with lobectomy in Stage I with a five year survival rate of 45%. In Stage II, pneumonectomy is the satisfactory operation (no five year cure with lobectomy, but 25,2% with pneumonectomy). Exploratory thoracotomy does not shorten the life expectancy and it should therefore be performed in doubtful cases.

Adenocarcinoma↗
PubMed1972

[From my work].

Explore the source record for details and available documents.

Academies and Institutes↗
PubMedDate not supplied

Localisation of glycans in the placenta: a comparative study of epitheliochorial, endotheliochorial, and haemomonochorial placentation.

Specimens of mid-term (horse), near-term (pig, cow, sheep, mink) and term (human) placentae and associated tissues have been examined with a panel of 15 biotinylated lectins combined with an avidin-peroxidase revealing system. The aim of this study has been to analyse the expression of glycans at the materno-fetal interface in order to establish whether the morphological diversity exhibited by these six species is reflected by accompanying biochemical diversity, or whether similar types of glycan are expressed in tissues performing similar functions. Lectin staining intensity was scored in the following elements of the interhaemal placental barrier: maternal capillaries, maternal uterine epithelium, the materno-fetal interdigitating microvillous membrane (brush border in the human), trophoblast, and fetal capillaries. A high degree of biochemical diversity was found in the glycan expression of the various placental components within and among placental types. Each layer showed widely differing patterns of lectin binding between species, with only a few findings in common: 1) the relative lack of simple fucosyl termini, 2) the presence of non-bisected bi/tri-antennary N-glycan in most layers, 3) an abundance of terminal N-acetyl galactosamine, and 4) the restriction of high mannose glycans to intracellular granules. This diversity may be a mechanism to avoid hybridisation, although glycan patterns may change between conception and placental development, or it may have evolved as a consequence of morphological changes. It is possible that it may also be part of the cause, rather than the result, of the structural diversity that is so characteristic of mammalian placentation.

Animals↗
PubMedDate not supplied

Vascular interrelationships of near-term mink placenta: light microscopy combined with scanning electron microscopy of corrosion casts.

The microvasculature of the near-term zonary placenta of the mink has been studied using light microscopy and scanning electron microscopy of corrosion casts, prepared from maternal and fetal vessel systems, respectively. The zonary area, most important for placental exchange, includes a characteristic labyrinth. The labyrinth is composed of lobules oriented in a maternal-fetal direction. One maternal stem artery serves as the central axis of a lobule, and about six pairs of fetal stem arteries and stem veins of the chorionic primary villi mark the periphery of the lobule. Viewed from the fetal side of the labyrinth, this lobular structure presents a roughly hexagonal pattern, with the central maternal stem artery and radially oriented arteriolar branches giving the lobule the shape of a star. These arterioles frequently form bridges to neighboring lobular systems; however, the majority continue into the feto-maternally oriented three-dimensional network of maternal capillary sinusoids, which converge on the outlets of the maternal stem veins on the maternal side of the labyrinth. Maternal main crypts are delimited by the rays of the star-shaped lobules containing chorionic primary villi. The latter penetrate into maternal crypts from the fetal side, and are characterized by their axial arterial and venous stem vessels. Fetal secondary villi are arranged at different levels from these stem vessels. The secondary villi are characterized by arterioles and venules branching in pairs from the stem vessels and supply the tributary capillary complexes of terminal villi. The lobular structure of the placental labyrinth provides a three-dimensional framework of vessels where maternal capillary sinusoids and fetal capillaries meet in a one-way cross-current arrangement. The blood flow conditions and the peculiarities of the mink placenta interhemal membrane are compared to those of other carnivores and discussed with respect to the efficiency of the endotheliochorial placenta.

Animals↗
PubMedDate not supplied

Placental vascular corrosion cast studies: a comparison between ruminants and humans.

The microvasculature of both the ruminant placentomes of cattle, sheep, and goats and the human placenta were compared, using corrosion casts of blood vessels and scanning electron microscopy. The fetal vascular trees of ruminant and human placenta differ in form and size, which correlates with the degree of ramification; however, their architecture of stem, intermediate, and terminal villi is similar. In the human, the system of serially linked capillary convolutions of terminal villi is longer than that in ruminants. Therefore, in guaranteeing blood flow against flow resistance, the human vessels particularly need a straight course, anastomoses, and sinusoidal dilations. Specifically in the ruminants studied, the venous vessels outweigh the arterial ones by volume and by number. They are suggested to be absorptive for substances metabolized in the zone of the capillary complex. The most extreme interspecies difference relates to the maternal vasculature, which, in contrast to the fetal system, is a closed system in the ruminant septas and an open lacunal intervillous space in the human. Converging and differing morphological vascular phenomena of ruminants and human placenta are discussed in terms of maternofetal exchange related to placental efficiency. In summary, the ruminant placenta, concerning the fetal vascular tree, in many aspects is workable as a model for the human.

Animals↗