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Biomedical subjects

J Winter

Publications and source records attributed to J Winter.

At least 253 records · Page 14Linked to original sources
PubMed1983

Inactivation of contraceptive steroid hormones by human intestinal clostridia.

Steroid hormones reduced in ring-A are devoid of hormonal activity. In metabolic experiments we found that human fecal flora reduced the delta 4-3-keto structure of natural progestins to 3 alpha-hydroxy, 5 beta-steroid metabolites (3 alpha,5 beta) and of synthetic progestins to a mixture of 3 alpha,5 beta and 3 beta,5 beta compounds. 3 alpha,5 beta-Reductase was synthesized by Clostridium paraputrificum and had a strong affinity for natural progestins such as progesterone. 3 beta,5 beta-Reductase was synthesized by Clostridium innoculin and had a stronger affinity for synthetic progestins. A third enzyme, 3 beta,5 alpha-reductase, was synthesized by St. Luke's strain 209 (Clostridium species "J-1") but was only observed when pure cultures were used. Ring-A reduction of synthetic progestins was 3 to 10 times slower than that of natural progestins, thus explaining the pharmacological superiority of synthetic progestins over naturally occurring analogs.

Clostridium↗
PubMed1983

Gray scale of ultrasound instruments: evaluation using a test object.

B-mode scans of castor oil in a wedge-shaped container provide gray level maps. The relation between the gray levels and the amounts of absorbing medium can be used to measure the effects of electronic gain, transducer characteristics, and the overall gray level performance of different ultrasound systems. We report results from four units and ten transducers for varying scanning depths.

Castor Oil↗
PubMed1983

Low-cost digital teleradiology systems.

The proliferation of digital imaging methods creates a need for systems that facilitate storage and retrieval of these images. Several low-cost systems with the capability to store, retrieve, and transmit digital images from the medical center to distant general-purpose desktop microcomputers over standard telephone lines were investigated. Using error checking and nonlinear gray scales, both bistable and gray scale display systems were able to transmit and reproduce diagnostic quality images. The major limitations are the lack of low-cost digital mass-storage devices and relatively slow transmission times.

Information Systems↗
PubMed1983

Fecal steroid 21-dehydroxylase, a potential marker for colorectal cancer.

Eubacterium lentum and phenotypically similar organisms synthesize a steroid 21-dehydroxylase which converts biliary tetrahydrodeoxycorticosterone to pregnanolone. Tetrahydrodeoxycorticosterone, in contrast to pregnanolone, is carcinogenic for hamster embryonic cells (HECT test). In patients with recently diagnosed, untreated sigmoidal or rectal cancer the fecal concentration of 21-dehydroxylating organisms is reduced by more than 99% as compared with age-matched controls. The lack of fecal 21-dehydroxylating organisms, therefore, is a potential marker for the disorder. The role of steroid 21-dehydroxylase in the pathogenesis of colorectal cancer is unknown.

Adult↗
PubMed1983

[Colitis in the non-functioning rectosigmoid after establishment of an end-sigmoid colostomy].

In 11 patients with a sigmoid end colostomy (and one additional patient with an end ileostomy), we examined the endoscopic and microscopic aspects of both the dysfunctioned bowel and the colon proximal to the colostomy. The latter showed in none of the cases signs of inflammation, while in 7 patients a remarkable or even severe colitis (mimicking ulcerative colitis) could be demonstrated endoscopically and/or histologically - irrespective to the duration of the dysfunction (one month up til 11 years). In the four patients with restoration of the intestinal continuity, macroscopic and microscopic findings of the rectal mucosa became normal as soon as two weeks after reoperation. We conclude, that the "dysfunctioned bowel-colitis" is somehow related to the mucosa's contact to the fecal stream.

Aged↗
PubMed1982

Shiverer peripheral myelin contains P2.

Myelin-deficient mutant mice, such as shiverer, can provide information about the normal mechanisms involved in myelination. The shiverer mouse carries a recessive, autosomal mutation resulting in an extreme deficiency in central myelin, and the small amount of myelin present is poorly compacted; the peripheral myelin, however, appears essentially normal. As the amount of myelin basic protein (P1) in both central and peripheral nervous system myelin is extremely low in shiverer, it is possible that P1 is essential for the normal formation and compaction of central myelin, but not of peripheral myelin. Some other protein would then be responsible for the formation of compact peripheral myelin in shiverer. Peripheral myelin contains another basic protein, designated P2, which could be a possible candidate for this role. Kirschner and Ganser, however, using SDS-polyacrylamide gel electrophoresis, reported that P2, as well as P1, is absent from shiverer sciatic nerve. This is an important observation if correct, because it not only excludes the possibility that P2 is required for compaction but also makes it less likely that the deficiency in P1 is the primary defect in shiverer. As P2 in rat and mouse has frequently been confused with another small basic protein (related to P1) in SDS-polyacrylamide gels, it seemed worthwhile to reassess this aspect of the Kirschner and Ganser observations. Immunohistochemistry and immunoblotting have been used here to show unambiguously that P2 is present in shiverer peripheral myelin.

Animals↗
PubMed1982

Cerebral metabolism and atrophy in Huntington's disease determined by 18FDG and computed tomographic scan.

Patterns of local cerebral glucose utilization were measured with positron emission, computed tomography using the 18F-fluorodeoxyglucose method in 13 patients with Huntington's disease (HD), 15 subjects at risk for HD, and 40 normal control subjects. These data were compared with computed tomographic measures of cerebral atrophy, with age, and with duration and severity of symptoms. The results indicate that in HD there is a characteristic decrease in glucose utilization in the caudate and putamen and that this local hypometabolism appears early and precedes bulk tissue loss. In contrast to patients with senile dementia, in these HD patients glucose utilization typically was normal throughout the rest of the brain, regardless of the severity of symptoms and despite apparent shrinkage of brain tissue. Our results suggest the possibility that the caudate may be hypometabolic in some asymptomatic subjects who are potential carriers of the autosomal dominant gene for HD.

Adolescent↗
PubMed1982

Immunocytochemical study of the appearance of P2 in developing rat peripheral nerve: comparison with other myelin components.

Using indirect immunofluorescence on both dissociated cell cultures and frozen sections from rat sciatic nerve, dorsal root ganglion and superior cervical ganglion, we have examined the development and distribution of the peripheral myelin protein P2. It first appears in development in sciatic nerve and dorsal root ganglion on the first day of birth, at about the same time as P0 and P1. Like galactocerebroside, P0 and P1, P2 disappears gradually from dissociated Schwann cells in culture. In adult sciatic nerve, and dorsal and ventral roots, it shows an uneven distribution and is absent from some myelinated axons. In electron micrographs the onset of myelination in the sciatic nerve occurs between the day of birth (day 0) and the first day after birth (day 1). Immunofluorescence studies on freshly dissociated cell suspensions, frozen sections and dissociated cell cultures at these early time points indicate that the myelin glycolipids galactocerebroside and sulphatide are present on the surface of many schwann cells at least one day before myelination starts while the myelin proteins P0, P1 and P2 are not detected until myelination begins. This suggests that the early appearance of galactocerebroside and sulphatide is an important step preceding the formation of compact myelin.

Animals↗
PubMed1982

16 alpha-dehydration of corticoids by bacteria isolated from rat fecal flora.

Two strains (No. 144 and No. 146) of rat intestinal anaerobic bacteria, phenotypically similar to Eubacterium lentum, were isolated and found capable of 16 alpha-dehydrating corticoids. The initial step in the 16 alpha-dehydration of 16 alpha-hydroxyprogesterone was dehydration at the C-16 and C-17 position with the accumulation of 16-dehydroprogesterone. This step required the side chain at C-17. In bacterial cultures the 16-dehydroprogesterone was then slowly reduced to iso-progesterone. 16 alpha-Hydroxypregnanolone was also converted to iso-pregnanolone by these bacteria. 16 alpha-Dehydratase was easily demonstrated in cell fractions of strain No. 144 incubated either aerobically or anaerobically. The same extracts did not convert 16-dehydroprogesterone to iso-progesterone under similar assay conditions. 16 alpha-Dehydration occurred at all substrate concentrations tested (20 to 200 micrograms/ml) provided the pH of the growth medium was between 6 abd 8 and the Eh below -130 mV. Strain No. 146 had both 16 alpha-dehydration and 21-dehydroxylation activities. The two enzymes functioned independently. A role for intestinal bacteria in the biotransformation of biliary 16 alpha-hydroxylated steroids and subsequent excretion in the urine is proposed.

Adrenal Cortex Hormones↗
PubMed1982

Formation of 20 beta-dihydrosteroids by anaerobic bacteria.

Cortisol was metabolized to a variety of products, among them small amounts of cortol by fecal flora of humans and rats. A microorganism, Bifidobacterium adolescentis, isolated from both sources, synthesized a 20-hydroxysteroid dehydrogenase which reduced cortisol to 20 beta-dihydrocortisol. The metabolite was reduced to cortol by Clostridium paraputrificum. The 20-hydroxysteroid dehydrogenase showed a wide substrate specificity; it was independent of the 4-ene and the configuration at C3, C-11, C-17 and C-21. Cortol was resistant to any further alteration by human fecal flora, i.e. it is a metabolic end product. As expected, B. adolescentis effectively prevented 21-dehydroxylation of cortisol by Eubacterium lentum.

Adrenal Cortex Hormones↗
PubMed1982

Pulmonary hamartoma.

From 1973 to 1980, 9 pulmonary chondromatous hamartomas of the lung were resected at our Clinic. One of these hamartomas was a rare endobronchial chondroma. To our knowledge, 91 cases of endobronchial hamartomas have been described in the previous literature. Although a similar origin of intrapulmonary and endobronchial hamartomas is postulated, there is a difference in their clinical features. The endobronchial type of hamartoma often causes respiratory symptoms of obstructing the bronchus with consequent destruction of the distal lung, whereas patients with intra-pulmonary hamartomas are symptom-free.

Adult↗
PubMed1982

[Sonographic appearance of renal fibrolipomatosis].

Diagnostic ultrasound studies were performed in 104 patients with renal fibrolipomatosis. The lesions were echo-poor in 94 of 104 cases and echogenic in the remaining 10 patients. The echo-poor lesions presented multiple echo-poor zones, a single echo-poor region of a finger-shaped configuration. The latter pattern resembled hydronephrosis. Differentiation between the two lesions was possible on the basis blurred contours, absence of increased transmission and lower echo intensity in fibrolipomatosis than in urinary tract obstruction. Cases of echogenic fibrolipomatosis are characterized by a high proportion of collagen fibres. Differential diagnosis of these lesions including tumours of the renal parenchyma and pelvis are discussed.

Humans↗