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Biomedical subjects

J Weber

Publications and source records attributed to J Weber.

At least 685 records · Page 38Linked to original sources
PubMed1979

[Determination of the quality of injuries of potato tubers due to damage and rot].

A new method is presented for determining damage to potato tuber tissue. It is based on the fact that starch can be leached with water from the damaged tissue. The starch content of the washing water informs about the extent of tissue damage. Damage assessments of the same samples yielded correlation coefficients ranging from r = 0.8 to r = 0.9 between the determinations and the assessments. The method considers both the mechanical tissue damage and the rot.

Food Handling↗
PubMed1979

On the mechanism of arginine requirement for adenovirus synthesis.

The effects of arginine deprivation on the synthesis and processing of viral proteins and the assembly of incomplete and complete virions were studied during infection with human adenovirus type 2. Arginine deprivation greatly reduced the synthesis of all viral proteins, particularly the precursor to core protein VII. The inhibition was completely reversible by the addition of arginine to the medium. Arginine deprivation between 7 and 20 hours post-infection inhibited the processing of PVII to VII, suggesting that PVII is not cleaved autocatalytically. The assembly of incomplete virions was sensitive to arginine deprivation only prior to 20 hours, while the assembly of complete virions was dependent on the continuous presence of arginine. This observation supports the hypothesis that incomplete virions are precursors of complete virions. The experiments on the PVII-specific endoprotease activity showed that arginine deprivation caused only slight reduction in the in vitro activity, although no activity was observed in vivo. The present results lead to the hypothesis that arginine deficiency inhibits the synthesis of a functional protein essential for virion maturation, other than the synthesis or processing of PVII.

Adenoviruses, Human↗
PubMed1979

Modulation of sympathetic vascular tone by prostaglandins in corticosterone-induced hypertension in rats.

1. In corticosterone-induced hypertension in rats the activity of the peripheral sympathetic nervous system and its modulation by prostaglandins was studied. 2. Plasma concentrations of noradrenaline were reduced if compared with those in normotensive control rats. 3. The sensitivity of the isolated perfused hind-limb preparation to noradrenaline was enhanced before blood pressure rose and increased further with the development of hypertension. 4. Arachidonic acid, prostacyclin (prostaglandin I2), but not 6-keto-prostaglandin F1 alpha, reversed the supersensitivity to noradrenaline. 5. These results suggest that corticosterone induces a supersensitivity to noradrenaline by inhibiting the biosynthesis of prostaglandins. Changes in the sensitivity of the vascular smooth muscle may play a role in the development of glucocorticoid hypertension.

Animals↗
PubMed1979

[Phlebography for pre- and posttherapeutic control of fibrinolysis and thrombectomy (author's transl)].

The indications for fibrinolysis or thrombectomy when there is suspected fresh ilio-femoral venous thrombosis should be based on accurate phlebography at the earliest possible moment. Early posttherapeutic phlebography under standardised conditions should be used to control further treatment. Later examinations document the final outcome. Early phlebography, when treatment has been discontinued and has been unsuccessful, shows the so-called "Rischhalte phenomenon", which may be an indication for further thrombectomy. Seven cases are reported in which primary fibrinolysis with streptokinase was followed by thrombectomy with a Fogarty catheter. 3-Step-phlebography provides the essential information which governs treatment and demonstrates its results.

Femoral Vein↗
PubMed1979

Genetic analysis of adenovirus type 2. IX. The physical locations of structural genes.

Several virus-specified proteins of adenovirus type 2 (Ad2) and type 5 (Ad5) can be distinguished by their differential electrophoretic mobility in SDS-polyacrylamide gels. By comparing the physical maps of the genomes of interserotypic recombinants between ts mutants of these viruses with the pattern of proteins expressed, the physical locations of some genes can be determined on the adenovirus DNA molecule. The proteins of a total of 103 recombinants were analysed; 44 of these are of known DNA structure. Structural genes for the proteins analysed span the following loci on the conventional adenovirus map: V (30 to 43); III (43 to 44); II and 66K (55 to 57); 100K, 36K, 32K (69 to 71); IV (80 to 90).

Adenoviruses, Human↗
PubMed1979

Uncoating of adenovirus type 2.

The uncoating of adenovirus type 2 and a temperature-sensitive mutant, tsl, was studied. HEp-2 cells were infected with 32P- OR 125I-labeled purified virions for various lengths of time, and the nuclear and cytoplasmic fractions were analyzed by sucrose gradient velocity sedimentation and sodium dodecyl sulfate-polyacryl-amide gel electrophoresis. Within 1 h of infection, virions were converted into three subviral structures: (1) subviral structures in the cytoplasm with a density greater than virions but which qualitatively still contained all virus polypeptides; (ii) corelike structures associated with both the nuclear and cytoplasmic fractions and composed of viral DNA and polypeptides VIa2, V and PVII; and (iii) putative DNA-terminal protein complexes in the nuclei. The kinetic and compartmentalization studies suggested that the DNA-terminal protein complex is the end product of uncoating. The virions which were synthesized by tsl at the nonpermissive temperature and contained the precursor polypeptides PVI and PVII were found to be blocked in uncoating at the corelike stage. This block in uncoating provides the explanation for the lack of infectivity of these virions. A model for the uncoating of adenovirus is proposed.

Adenoviruses, Human↗
PubMed1979

[Formation of chondroid tissue in the left ventricle and bundle of His in complex congenital cardiac abnormality (author's transl)].

The formation of chondroid tissue in the heart ventricles and in the region of the ventriculoatrial transition is regarded as a rare lesion of the human heart. We present the observation of a not well-known disorder of cardiac development connected with a cartilagineous transformation of endo- and myocardial tissue. Chondroid change was found in the innermost parts of the left ventricle in a heart with severe hypoplasia of left parts and aortic atresia. Cartilage-like tissue reached to the region of the bundle of His and to supraanular parts of the interatrial septum. The possible genesis of this change, that may be of clinical relevance, is discussed with regard to normal endo- and myocardial development.

Autopsy↗
PubMed1978

Renal occlusion phlebography: applicability of the balloon catheters.

The technique of selective renal occlusion phlebography using Swan-Ganz or Dotter-Lucas balloon catheters is described. The Swan-Ganz catheter is introduced into the femoral vein with the aid of a Cordis introducer system. The Dotter-Lucas balloon catheter is inserted via the same route using a combination of either a Desilets-Hoffman or Edslab introducer, along with a Gebauer introducer. Occlusion of the renal vein is achieved by insufflation of the balloon with air or injection of saline or dilute contrast media into the balloon. Selective renal occlusion phlebography was performed in 116 patients in order to exclude renal vein thrombosis, to delineate poorly vascularized renal masses, to determine the venous involvement of a renal tumor, and to assess the patency of splenorenal shunts. Renal occlusion phlebography optimizes the retrograde opacification of the renal veins. It has value in the delineation of poorly vascularized renal masses and in the determination of the venous involvement of renal and retroperitoneal tumors, and it would seem to be the method of choice for demonstrating the patency of surgical splenorenal shunts. Further enhancement of venous opacification by the combination of temporary arterial vasoconstriction with angiotensin (pharmaco-occlusion phlebography) and venous balloon occlusion is useful in some cases.

Adenocarcinoma↗
PubMed1978

Cocarcinogens of the diterpene ester type from Croton flavens L. and esophageal cancer in Curaçao.

From the roots of Croton flavens L., 3 highly irritant and tumor promoting Croton factors F1--F3 and the corresponding 3 cryptic Croton factors F'1--F'3 were isolated and characterized as novel esters of 16-hydroxy- and 4-deoxy-16-hydroxyphorbol, respectively. These findings suggest that tumor promoters of the phorbol ester type, ingested through the widespread and frequent use of Croton flavens according to local habits, may be causally related to the well recognized high rate of esophageal cancer on Curaçao.

Animals↗
PubMed1978

[Technical aspects of phlebography in varicosis of the lower limbs (author's transl)].

Ascending phlebography is a safe and reliable method for preinterventional differential diagnosis of primary and secondary venous insufficiency. With the combined use of fluoroscopy and spot filming, the technique yields functional information on the venous valves and communicating veins. It also permits exact localization of peripheral and proximal varicosis and venous aneurysms. In addition, the plevic and inferior vena cava inflow can be evaluated.

Fluoroscopy↗