Biomedical subjects
W Winter
Publications and source records attributed to W Winter.
[Mechanical aspects of the development of artificial heart valves].
The development of an antithrombogenic coating permits a hybrid design for artificial heart valves. A substrate material optimized for its application is coated to meet the electrochemical requirements of improved hemocompatibility. But future progress in artificial heart valves requires an improvement in design as well as of the material. The basis of both aspects is the determination of such fundamental mechanical properties as the elasticity and plasticity of the valve ring and the deformation and fraction behaviour of the occluder. Analytical and numerical calculations of various different models result in different requirements for the substrate of ring and occluder. A combination of high elastic temper and low resistance to flow requires a ring material with a Young's modulus of 40 GPa or more, and a 0.2% proof stress to (Young's modulus)2/3 ratio of 0.3 MPa1/3. The best occluder materials should have a Young's modulus of more than 50 GPa and a flexural strength of at least 800 MPa. On the basis of these criteria, a heart valve consisting of a TiA15Fe2,5 ring and occluders made partially stabilized zirconia is introduced.
[User software for interactive design of prosthesis shafts].
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[Procollagen III peptide (P-3-P): is it necessary in liver diagnosis?].
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[Retinal detachment of various etiologies. Clinical aspects and the results of surgical treatment].
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Rheumatoid nodules of the spine: case report and review of the literature.
We present the case of a patient who had rheumatoid nodules of the vertebrae, which had resulted in bony destruction of the spine at 3 levels. Although there have been only 3 previous reports of such findings with confirmation by histologic analysis, we believe the condition is more common than has been thought. From a review of the literature, we found that similar clinical and radiographic features, as well as descriptions of rheumatoid granulation tissue invading the disc spaces, have been described in several subjects.
Molecular genetics of insulin-dependent diabetes mellitus.
Insulin-dependent diabetes mellitus is an autoimmune disease the development of which is influenced by genetic factors (Cahill & McDevitt, 1981). As concordance for IDD is less than 50% in identical twins, environmental factors are also required for the development of IDD. Although viral agents have been implicated in the past, the specific environmental components leading to IDD remain unknown. This paper reviews current research focused on the genetic factors that influence susceptibility to IDD.
[Visual acuity and static perimetry after the operation for retinal detachment].
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[Distal radius fractures at a municipal clinic. Causes, treatment and results].
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[Results and limits of episcleral buckling and cerclage surgery in retinal detachment].
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Neural crest cell migration to placenta.
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[Studies on the stress behavior in the interface of total hip prosthesis].
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Sickle Lepore hemoglobin identified in a black American infant.
An integrated newborn infant screening, follow-up testing, and counseling service for hemoglobinopathies creates opportunity for early medical management of disease processes, assistance to parents in developing coping strategies, and educational counseling about recurrence risks in subsequent pregnancies. These objectives were operative in a case of sickle Lepore hemoglobin identified through a newborn infant screening service. The initial screening test was reported as Hb AS. Follow-up electrophoresis on cellulose acetate was compatible with Hb SS, but in citrate acid agar gel there were major and minor zones of S and A mobility, respectively. This and other hematologic parameters in both the child and his father were compatible with a sickle Lepore phenotype. This was supported by a tryptic peptide map of the purified variant hemoglobin from the father. Without a follow-up testing and counseling service, this case would probably have been missed until manifestation of clinical phenotype.
Successful treatment of a patient with retractile mesenteritis with prednisone and azathioprine.
A patient with retractile mesenteritis is discussed, who presented with a huge 15 X 15-cm inflammatory mass involving the root of the mesentery. Gradually the patient developed duodenal obstruction for which it was necessary to perform a gastroileostomy. Because of a relentless downhill course with fever, weight loss, general malaise, and fatigue, it was finally decided to treat the patient with prednisone and azathioprine. Upon institution of this treatment there was a steady, progressive clinical amelioration with disappearance of fever, improvement in laboratory findings, and gradual regression of the lesion until it became a well-delineated hard mass that was thought to be the end stage of fibrosis. Early trial with such a treatment, once the diagnosis is firmly established, should be considered.
[Biological material and silicone inlays in the surgery of retinal detachment (author's transl)].
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Radionuclide fetal imaging: radio-activity in the fetal bladder confirmed by ultrasound after maternal hepato-biliary scanning.
Hepato-biliary scanning with 99mTc-P.G. demonstrated in a jaundiced patient at 31 weeks pregnancy the filling of the fetal bladder 6 h after injection. This finding was confirmed by ultrasound. Fetal urinary bladder activity was seen until 33 h after injection. Fetal hepatic radio-activity could not be displayed although the localisation of the fetal liver was marked by ultrasound.
[Clinical data on the frequency, localization, and surgical therapy of bone tumors (author's transl)].
Between 1973 and 1978 a total of 77 patients suffering from a tumor of bone were treated and followed up at this hospital. Of these patients, 52 were found to have benign tumors and pathologic tumorlike changes of bone. 25 were found to have semimalignant and malignant tumors. This paper describes localisation of bening semimalignant and malignant tumors of bone by means of a modified WHO-classification. The surgical treatment of different bone tumors is discussed on the basis of special cases.
Hepatobiliary scanning with 99mTc-pyridoxylidene glutamate. A retrospective study investigating the criteria for differentiation between intrahepatic and extrahepatic obstruction.
In 70 99mTc-pyridoxylidene glutamate (PG) studies with verified diagnoses, the following scan patterns were found. (1) Normal: within 30 min of PG injection the scan reveals the liver, hepatic ducts, common bile duct, gallbladder and flow to the intestine; after 2 h the liver had a higher concentration of activity than the hepatic ducts or the common bile duct. (2) Complete extrahepatic obstruction: no hepatic excretion to the intestine is observed 18-24 h after PG injection, nor is activity observed in the hepatic ducts, common bile duct and gallbladder. (3) Incomplete extrahepatic obstruction: intestinal activity is observed within 18-24 h of PG injection; after 2 h the concentration of activity in the hepatic ducts or the common bile duct exceeds that in the liver (regardless whether activity is or is not demonstrated in the gallbladder). (4) No extrahepatic obstruction: serum bilirubin normal or increased; intestinal activity is observed within 18-24 h after PG injection, and activity is demonstrable during this period somewhere in the hepatic ducts, the common bile duct or the gallbladder; after 2 h the concentration of biliary activity should not exceed that in the liver. (5) If excretion to the intestine is observed within 18-24 h of PG injection without demonstrable activity in the hepatic ducts, common bile duct or gallbladder, then it is impossible to differentiate between (3) and (4).