Search PubMed⌕ Search

Biomedical subjects

H Weiss

Publications and source records attributed to H Weiss.

At least 361 records · Page 20Linked to original sources
PubMed1979

Isolation of mitochondrial succinate: ubiquinone reductase, cytochrome c reductase and cytochrome c oxidase from Neurospora crassa using nonionic detergent.

The electron transfer complexes, succinate: ubiquinone reductase, ubiquinone: cytochrome c reductase, and cytochrome c: O2 oxidase were isolated from the mitochondrial membranes of Neurospora crassa by the following steps. Modification of the contents of the complexes in mitochondria by growing cells on chloramphenicol; solubilisation of the complexes by Triton X-100; affinity chromatography on immobilized cytochrome c and ion exchange and gel chromatography. Ubiquinone reductase was obtained in a monomeric form (Mr approximately 130 000) consisting of a flavin subunit (Mr 72 000) an iron-sulfur subunit (Mr 28 000) and a cytochrome b subunit (Mr probably 14 000). Cytochrome c reductase was obtained in a dimeric form (Mr approximately 550 000), the monomeric unit comprising the cytochromes b (Mr each 30 000), a cytochrome c1 (Mr 31 000), the iron-sulfur subunit (Mr 25 000), and six subunits without known prosthetic groups (Mr 9000, 11 000, 14 000, 45 000, 45 000, and 52 000). Cytochrome c oxidase was also isolated in a dimeric form (Mr approximately 320 000) comprising two copies each of seven subunits (Mr 9000, 12 000, 14 000, 18 000, 21 000, 29 000, and 40 000). The complexes were essentially free of phospholipid. Each bound one micelle of Triton X-100 (Mr approximately 90 000). After isolation, the bound Triton X-100 could be replaced by other nonionic detergents such as: alkylphenyl polyoxyethylene ethers, alkyl polyoxyethylene ethers and acyl polyoxyethylene sorbitan esters.

Chloramphenicol↗
PubMed1979

Enzymology of ubiquinone-utilizing electron transfer complexes in nonionic detergent.

The enzymology of isolated succinate: ubiquinone reductase and ubiquinone: cytochrome c reductase in nonionic detergents (alkyl polyoxyethylene derivatives) was studied. In the membrane the two multiprotein complexes and their hydrophobic substrates ubiquinone and dihydroubiquinone, are embedded in a common lipid bilayer. In detergent solutions the complexes are each inserted into micelles. Detergent micelles also serve as a solvent for the complexes hydrophobic substrates. As a consequence the isolated complexes are in a discontinuous phase with respect to their hydrophobic substrates and with respect to each other. Three types of assays were used. Firstly, single enzyme assays in which the hydrophobic substrates had to transfer from free micelles to the complex-bound micelles in order for enzyme reactions to occur. Secondly, assays in which the enzymic reactions were coupled to auxiliary nonenzymic reactions which rapidly converted the hydrophobic products back into substrates within the complex-bound micelle. Dichloroindophenol was used for the oxidation of dihydroubiquinone and dihydroduroquinone for the reduction of ubiquinone. Thirdly, assays in which the succinate: ubiquinone reductase reaction was coupled with the ubiquinone: cytochrome c reductase reaction. With the first type of assay, the kinetics of the substrate transfer reaction was dependent upon the type of detergent. In detergents with small polyoxyethylene head groups the transfer reactions were rate-limiting, and in detergents with large polyoxyethylene head groups the transfer reactions were fast and the enzymic reactions were rate-limiting...

Animals↗
PubMed1979

Plasma cell dyscrasia. Analysis of 423 patients.

Present clinical and laboratory diagnostic criteria permit a more accurate diagnosis and closer follow-up of patients with plasma cell dyscrasias. A ten-year follow-up of a group of 423 patients showed that the indications for and the adjustment of treatment are more precise when these criteria are summarized into profiles based on each diagnostic category. M components may be an indication of the presence of another sometimes nonreticular malignant neoplasm. The improvement of the specificity and sensitivity of immunologic methods sheds additional light on mechanisms controlling the synthesis of homogeneous antibodies such as prevalence of IgM-K in mixed cryoglobulinemia and lambda-light chains in IgD myeloma, excretion of lambda-Bence Jones proteins in amyloidosis, and greater IgG-subclass restriction in multiple myeloma as compared with benign monoclonal gammopathy. The activation of additional clones (biclonal gammopathies) was found in 3% of our patients.

Adult↗
PubMed1979

[Ultrasound as a diagnostic procedure in liver disease: results of 3000 sonographic investigations (author's transl)].

3000 sonographic examinations of the liver were performed. The results of 142 sonographic studies were compared with the findings obtained by subsequent laparoscopy and microscopy. In 90% there was good agreement between the sonographic diagnosis and the microscopic findings. Fatty liver (97%) and metastasis (95%) into the liver were diagnosed accurately. 3 hematomas of the liver were found in 150 patients who underwent liver biopsy. Sonographic examination of the liver is usefull in: (1) determining topographic anatomy of the liver before needle biopsy. (2) deciding the next diagnostic step within the catalogue of indications for the morphologic diagnosis of the liver given by the IASL. Ultrasound shortens diagnosis. (3) early diagnosis of hematoma after liver biopsy.

Fatty Liver↗
PubMed1979

The clinical course of serpiginous choroidopathy.

We closely observed nine patients (17 eyes) with serpiginous choroidopathy for time periods ranging from two to ten years. There were seven men and two women with ages ranging from 22 to 58 years, average age was 46 years. Eight patients were bilaterally affected; one patient had only one eye. The clinical course of the disease was characterized by multiple recurrences. The recurrences and progression of the disease often were not noticed by patients if the macular area was not involved. Serial fundus photographs proved to be invaluable in establishing progression. Although the disease usually progresses in a centrifugal manner from the disk toward the periphery, three patients demonstrated centripetal progression and one of these three permanently lost central acuity. Visual acuity was affected only when the foveal or parafoveal areas became involved, but in nine of the 17 eyes, visual acuity returned to a variable degree. None of the patients had any general systemic illness. However, five of the patients reported chronic exposure to an unusual variety of chemicals.

Adult↗
PubMed1979

Intimal thickening of human femoral arteries with special regard to elastin, Part 1. Diffuse intimal thickening due to growth and age.

In infants, human femoral arteries display seam-like internal elastic lamina (IEL) covered with endothelium on the luminal side and with smooth muscle cells (SMC) on the medial side. At birth the growth of IEL is finished, correlated with a loss of microfibrils (MF) at the periphery. With the onset of the postnatal vessel growth the joints of IEL seem to be mechanically widened until they have the appearance of gaps with progressing age. After the age of 40 years there are often rod-like crystallites in the IEL, probably composed of cholesterol esters. A small first consecutive lamina (CL) can be seen already in childhood; it enlarges until the 3rd decade of life and is interpreted as a substitute to the "fragmented" IEL. After the 5th decade of life the first CL is arranged within the intima at a certain distance from the IEL and consisting of loosely arranged elastic fibrils. In very old arteries (beyond the 8th decade of life) gaps are rarely seen in the first CL. In individuals over the age of 30 years, the space between IEL and the first CL is occupied by smooth muscle cells (SMC) which are tightly packed. Additional CLs above the first CL can be found in elderly individuals, there CL obviously contribute to the intimal thickening. The ultrastructure of the elastic elements of the vessel wall and their possible function are discussed.

Adolescent↗
PubMed1979

Plasma renin, renin substrate and angiotensin II changes following experimental endotoxinaemia.

The effect of a single dose of endotoxin (B. coli, 1.5 mg/kg intravenously) on plasma renin concentration (PRC), renin substrate (PRSC), and angiotensin II (AT II) was studied in rats over a period of 48 hours. All determinations were performed by specific radioimmunoassay. Six and nine hours following endotoxin administration, renin secretion was decreased, whereas at 48 hours a slight increase in the PRC was found. In contrast, a three-fold elevation of the PRSC occurred during the first 24 hour period, attributable to a stimulation of the hepatic biosynthesis as result of corticosterone oversecretion. According to the observed changes in PRC and PRSC, AT II remains unchanged after six and nine hours, whereas a significant increase was detected after 24 and 48 hours. Based on the actual AT II level, the findings emphasize that in the rat the RAS does participate in the later stages of endotoxin stress only.

Angiotensin II↗
PubMed1979

[Ultrasound-guided needle biopsy of malignant liver cyst (author's transl)].

A liver cyst was detected during a routine ultrasonographic examination. Needle biopsy of the cyst was performed using ultrasound as a guidance device during puncture. Malignant cells could be demonstrated on cytological examination. Needle biopsy of circumscribed lesions of the liver is a low risk procedure, causing no strain for the patient. Needle biopsy should be done, when a hepatic cyst is detected by ultrasound, when there is suspicion of malignancy, and when a parasitic lesion has been excluded.

Aged↗
PubMed1979

[Delayed hypersensitivity against staphylococcal antigens in guinea pigs (author's transl)].

Delayed type hypersensitivity against staphylococcal antigens could be induced in guinea pigs by injecting the animals with a staphylococcal homogenate in Freund's adjuvant in all four foot pads and the nuchal skin. Maximal skin reactivity, tested intracutaneously, was observed 21 days after sensitization. Highest stimulation of lymph node cells and peripheral blood lymphocytes was also obtained 21 days after sensitization. When comparing cell walls, cell materials (nonsoluble material obtained after the separation of the cell wall fraction) and soluble fraction (obtained after sedimentation of all nonsoluble material, the strongest skin test reactions occurred after testing intracutaneously with the cell wall fraction.

Animals↗