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Biomedical subjects

J Winter

Publications and source records attributed to J Winter.

At least 271 records · Page 15Linked to original sources
PubMed1982

Computed tomography in diagnosis of intracranial tumors versus tubers in tuberous sclerosis.

Intraventricular gliomas producing obstruction of the foramen of Monro were observed by computed tomography in 4 of 8 patients with tuberous sclerosis. Bilateral tumors arising from the caudate nuclei were present in one patient. Characteristic subependymal calcified tubers were also seen, but contrast enhancement occurred only in the tumors and not in the tubers. The location of the tumor prevented communication between the 2 lateral ventricles so that surgical placement of a single ventricular shunt resulted in only unilateral relief of hydrocephalus. Shunting in one case was ineffective because of high cerebrospinal fluid viscosity due to elevated protein concentration.

Adolescent↗
PubMed1982

Immediate reinforcement in delayed reward learning in pigeons.

Pigeons were trained on simultaneous red-green discrimination procedures with delayed reward and sequences of stimuli during the delay. In Experiment 1, three stimuli appeared during the 60-second intervals between the correct responses and reward, and the incorrect responses and nonreward. The stimulus that immediately followed a correct response also preceded nonreward, and the stimulus that followed an incorrect response preceded reward. These stimuli were 10 or .33 second in duration for different groups. Stimuli during the remainder of the delay interval differed following correct and incorrect responses. Group 10 initially persisted in the nonrewarded choice, but shifted to a preponderance of rewarded responses after further training. Group .33 rapidly acquired the correct response. Similar results were obtained in Experiment 2 where delay intervals consisted of opposite sequences of two stimuli of equal duration and total delays were 6, 20, or 60 seconds. Early in training, generalization of differential conditioned-reinforcing properties from the conditions preceding reward and nonreward to postchoice conditions had a greater effect relative to backchaining than it did later. It was concluded that delayed-reward learning is best analyzed in terms of the conditioned-reinforcing value of the patterns of cues that follow immediately after rewarded and nonrewarded responses.

Journal Article↗
PubMed1982

Biotransformation of 16 alpha-hydroxyprogesterone by Eubacterium sp. 144: non-enzymatic addition of L-cysteine to delta 16-progesterone.

Eubacterium sp. 144 dehydroxylated 16 alpha-hydroxy-progesterone; however, the expected intermediate, delta 16-progesterone, did not accumulate to significant concentrations in the culture medium. Moreover, the final end product of this biotransformation, 17 alpha-progesterone, was produced at a very slow rate. It was discovered that, under our culture conditions, delta 16-progesterone reacted chemically with L-cysteine to form a highly water-soluble derivative. The ability of delta 16-progesterone to react with L-cysteine in culture media was considerably reduced when L-cysteine was autoclaved in the presence of complex medium components. delta 16-Progesterone also reacted chemically with D-cysteine, L-homocysteine, glutathione, and 2-mercaptoethylamine. The reaction was favored by alkaline pH (greater than or equal to pH 8.0) and required both an unhindered thiol group and a proximal amino group on the mercapto compound. Chromatography of the putative delta 16-progesterone L-[U-14C]-cysteine reaction product by HPLC showed a single UV-absorbing, radioactive peak (RT 4.31 min).

Biotransformation↗
PubMed1982

[The disinsertion of Vater's papilla in stomach resection. Causes, diagnosis and therapy].

Based on the experiences of our own with two papillary disconnections during partial gastric resection and 105 reports of the world literature (1916-1980), the cause, diagnosis and management of the injury is described. The most important factor favouring the operative accident is the foreshortening of the duodenum caused by the scarring of a chronic postbulbar ulcer. The ampulla of Vater may, therefore, be brought closer to the pylorus. The prognosis of the injury is not determined by the time of discovery, but it depends on the complete diagnosis of both severed ducts and adequate treatment. On delayed recognition the lesion may masquerade leaking of the duodenal stump. Successful repair can be achieved by reimplantation or invagination of the transsected common bile and pancreatic duct into the duodenal stump or an isolated Roux-en-Y-loop.

Adolescent↗
PubMed1981

Side-chain cleavage of cortisol by fecal flora.

The side chain of certain C-21 steroids may be removed by an enzyme, desmolase, synthesized by intestinal bacteria. With a view to isolate these organisms we examined the conditions required for their multiplication and function. The model substrate, cortisol (11 beta, 17 alpha, 21-trihydroxy-4-pregnene-3,20-dione), was metabolized by mixed fecal flora of humans and rats to a number of C-21 and C-19 compounds. The major C-21 metabolites were 21-deoxycortisol, tetrahydro-21-deoxycortisol, and tetrahydrocortisol. The C-19 metabolites obtained were identified as 5 beta-androstane-3 alpha, 11 beta-triol and 5 xi-androstane-3 alpha, 11 beta-diol-17-one. The prevalence of converting microorganisms was approximately 10(6)/g feces in both humans and rats. Conversion required an Eh below -130 mV, and an initial pH of 7.0. Optimal yield of C-19 products occurred with a fecal dilution of 10(5), though C-19 metabolites were evident from 10(1) through 10(8) fecal dilutions. Preliminary investigation indicates that the ability of converting organisms to form colonies varied with the composition of the media and the gaseous environment.

Aerobiosis↗
PubMed1981

Fitting a linear relationship with confidence intervals by correlation.

The study of the empirical linear relationship between two measured variables should use correlation analysis which treats the variables symmetrically, rather than linear regression which inappropriately assumes a dependent and an independent variable. An APL computer program calculates the best fitting bivariate Gaussian distribution and plots the data with the superimposed straight line relationship and the confidence interval.

Body Constitution↗
PubMed1981

Liposarcoma of the mediastinum. Case report and review of the literature.

A case of liposarcoma of the mediastinum in reported and a review of the literature is given. To our knowledge 53 cases have been described in the literature. The most common symptoms are dyspnea, chest-pain, a cough and loss of weight. There is no relation between operability, the duration of clinical symptoms and the size of the tumor. The final diagnosis was made by histological examination in all cases. A clinical classification of the tumor is not possible, because there are no characteristic clinical findings. The prognosis in general depends on the histological type of the malignant. Although recurrence of the tumor appears in more than 40% of cases, radical surgical resection is the only method of successful treatment. The significance of the five-year survival rate is doubtful, because recurrent tumors were reported up to 14 years after the initial surgical procedure.

Adult↗
PubMed1981

[Value of x-ray examination in diagnosis of carcinoma in chronic ulcerative colitis (author's transl)].

The risk factors of carcinogenesis in cases of chronic ulcerative colitis are discussed on the basis of a review of the literature, and the incidence of cancer in our own patients (3%) is compared with data in the literature. The limitations of radiological procedures for carcinoma diagnosis in cases of chronic ulcerative colitis are elucidated by discussion of the histogenesis and macropathology of the colitis carcinoma. The necessity for endoscopic-bioptic examination methods can be deduced from the frequent coincidence of dysplasias and colon carcinomas as well as from the great number of carcinomas not recognizable macroscopically.

Adult↗
PubMed1981

Computerized axial tomograms and dementia in elderly patients.

A correlational study comparing CT findings with the degree of dementia in 59 elderly patients revealed that cortical atrophy was related to age but not to dementia. Ventricular enlargement was also related to age but was statistically correlated with dementia. There was no relationship between cortical atrophy and ventricular size. These data suggest that CT findings of cortical atrophy in elderly patients should not be accepted as evidence of senile dementia.

Aged↗
PubMed1981

Correlation of biparietal and fetal body diameters: 12--26 weeks gestation.

One hundred thirty-four obstetrical diagnostic sonographic examinations were performed on patients of 12--26 gestational weeks. The following abdominal diameter measurements were obtained: (1) anteroposterior transverse diameter; (2) right-to-left transverse diameter; (3) average of (1) and (2); and (4) greatest longitudinal diameter. These measurements were plotted against the respective biparietal diameters, and normal statistical distribution curves were developed. These curves have proven helpful in cases with a questionable disproportionate relation between the fetal head and body size in early pregnancy. The data have facilitated identification of fetal abnormalities sufficiently early in the pregnancies to permit advising therapeutic abortion. Five cases outside the normal range are discussed and compared to normal. In several cases, the sonographic results played a major role in the decision-making process of the patient involved.

Adult↗
PubMed1981

Dehydroxylation of 16 alpha-hydroxyprogesterone by fecal flora of man and rat.

16 alpha-Hydroxyprogesterone, precursor of biliary 16 alpha-hydroxypregnanolone, was incubated with mixed fecal flora of humans and rats. The major steroid metabolite formed in both systems was 3 alpha-hydroxy-17 alpha-pregnan-20-one. These results demonstrated that the fecal flora reduced the delta 4-3 keto structure, removed the hydroxy group at C-16 and isomerized the side chain from the beta to the alpha configuration. Ring-A reduction of the substrate resulted in a 5 beta-compound with human flora and a 5 alpha-product with rat bacteria. The prevalence of 16 alpha-dehydroxylating organisms varied considerably in human fecal flora and was approximately 10(5)/g of feces in the three rats tested. Rat fecal flora dehydroxylated 16 alpha-hydroxyprogesterone after 4-5 days incubation at 37 degrees C, at pH 6.5-7.5, and with a substrate concentration of 20-80 microgram/ml (optimal condition). Preliminary evidence suggests that 16 alpha-dehydroxylase is exclusively of bacterial origin and is synthesized by an obligate anaerobe.

Adult↗
PubMed1980

[Diffuse polypoid lipomatosis coli with hypertrophy of the appendices epiploicae in congenital lipomatosis (author's transl)].

In a 62-year-old patient diffuse polypoid lipomatosis of the colon and hypertrophy of the appendices epiploicae was found together with subcutaneous lipomata and bone changes. Out of the five cases of diffuse lipomatosis coli published so far certain parallels can be drawn in only one case. The clinical picture and course indicate that it is either a pathogenetically uniform form of mesenchymal dysplasia or a syndrome.

Colon↗
PubMed1980

Effects of stroke on local cerebral metabolism and perfusion: mapping by emission computed tomography of 18FDG and 13NH3.

By means of emission computed tomography (ECT), we used 18F-fluorodeoxyglucose (18FDG) and 13N-ammonia (13NH3) as indicators of abnormalities in local cerebral glucose utilization (LCMRglc) and relative perfusion, respectively. The ECAT positron tomograph was used to scan normal control subject and 10 stroke patients at various times during recovery. In normal subjects, mean CMRglc was 5.28 +/- 0.76 mg per 100 gm tissue per minute (mean +/- SD; N = 8). In patients with stroke, mean CMRglc in the contralateral hemisphere was moderately decreased during the first week, profoundly depressed in irreversible coma, and normal after clinical recovery. Quantification was restricted by incomplete understanding of tracer behavior in diseased brain, but relative local distributions of 18FDG and 13NH3 trapping qualitatively reflected the increases and decreases as well as coupling and uncoupling expected for local alterations in glucose utilization and perfusion in stroke. Early after cerebrovascular occlusion there was a greater decrease in local trapping of 13NH3, than 18FDG within the infarct, probably because of increased anaerobic glycolysis. Otherwise, 18FDG was a more sensitive indicator of cerebral dysfunction than was 13NH3. Hypometabolism, due to deactivation or minimal damage, was demonstrated with the 18FDG scan in deep structures and broad zones of cerebral cortex that appeared normal on x-ray computed tomography and technetium 99m pertechnetate scans. In its present state of development, the 18FDG ECT method should aid in defining the location and extent of altered brain in studies of disordered function after stroke. With improved knowledge of tracer behaviour in diseased brain, the method has promise for mapping the response to therapeutic intervention and increasing our understanding of how the human brain responds to stroke.

Adult↗