In vivo dissection of the mitochondrial respiratory NADH: ubiquinone oxidoreductase (complex I).
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Intracellular Membranes↗
Biomedical subjects
H Weiss
Publications and source records attributed to H Weiss.
Disruption of the gene encoding the NADH-binding subunit of NADH: ubiquinone oxidoreductase in Neurospora crassa. Formation of a partially assembled enzyme without FMN and the iron-sulphur cluster N-3.
In this study, the gene of the 51-kDa NADH-binding subunit of the mitochondrial NADH:ubiquinone oxidoreductase (complex I) in Neurospora crassa was inactivated by homologous replacement with a defective gene copy. The resulting mutant, nuo51, lacks the 51-kDa subunit and shows no complex I activity but still grows at one third of the wild-type growth rate. The enzyme activity of the alternative NADH:ubiquinone oxidoreductase(s) is increased twofold while the activities of the other mitochondrial respiratory enzymes are normal. Complex I is almost completely assembled except for the NADH-binding subunit and still possesses three out of the four EPR-detectable iron-sulphur clusters. Since the deleted subunit contains the sequence motif for one tetranuclear iron-sulphur cluster, the missing cluster N-3 is considered to be bound to this subunit.
Binding Sites↗
Flow-cytometrically monitored chromatin in situ testing in the breast cell line H184A1N4.
Previous investigations in human precancerous and cancerous tissues identified subsets of cells that were different in respect to a heparin-induced increase in fluorescence intensity (IFI) monitored by flow cytometry. We suggested that differences in IFI were due to different chromatin types in the cells and related to different transcriptional capacities. This study is to prove our suggestion. Heparin-induced IFI was measured in the human breast cell line H184A1N4 cultured under different, defined growth conditions. Cells in quiescence obtained from a culture deprived of serum and other supplements essential for growth or from the confluent state revealed a higher IFI than cells restimulated to proliferation by addition of complete medium; here a reduced IFI was found. Changes in the magnitude of heparin-induced IFI precede changes in cell-cycle stage distribution by at least 6.5 h. We conclude that the heparin-induced effects, as revealed by flow cytometry, reflect changes in the accessibility of chromatin to transcription in different stages of proliferative activity. The results confirm our conclusions from previous findings with clinical material.
Breast Neoplasms↗
Increased serum iron and iron saturation without liver iron accumulation distinguish chronic hepatitis C from other chronic liver diseases.
One hundred twenty-three patients with chronic liver diseases of various etiologies were evaluated for their iron status. The patients were divided into four distinct groups: chronic hepatitis C (63), chronic hepatitis B (14), B + C (3) and nonviral chronic liver diseases (43). In 107 patients (87%) the chronic liver disease was confirmed by biopsy. Mean serum iron (+/- SD) levels in the above four groups were: 166 +/- 62, 103 +/- 52, 142 +/- 48, and 115 micrograms/dl; iron-binding capacity was 346 +/- 80, 325 +/- 72, 297 +/- 27, and 374 +/- 75 micrograms/dl, and iron saturation 50 +/- 18, 32 +/- 16, 48 +/- 16, and 28 +/- 10%, respectively. Serum ferritin, increased in all four groups, was highest in HCV; however, no evidence of hepatic iron accumulation could be found in any of the patients. There were no significant differences in liver function parameters measured in the four groups. We conclude that serum iron, iron saturation, and ferritin are increased in patients with hepatitis C in comparison to hepatitis B or other nonviral, nonhemochromatotic liver diseases. The increased iron status in hepatitis C patients is not manifested by increased liver iron. Awareness of these distinct features of chronic hepatitis C is essential in the diagnosis and treatment of chronic liver diseases.
Biopsy↗
Protective effects of various preservation solutions on cultured endothelial cells.
Vascular endothelium represents the first target in organ preservation and plays an important role in reperfusion injury. Bovine aortic endothelial cells were cultivated and the most commonly used preservation solutions, such as University of Wisconsin HTK (Brettschneider's histidine-tryptophane-ketoglutarate), and Euro-Collins solutions were tested on the endothelial monolayer. In addition, one group of cultivated cells was preserved with cold saline solution, and endothelial monolayers grown in culture medium were used as controls. The quality of preservation was assessed after 24, 48, and 72 hours of cold storage. Reperfusion was simulated and its effects were observed by reincubation in culture medium at 37 degrees C for 6 hours. The total number of cells, cell viability (determined using trypan blue exclusion), and morphologic alterations were determined. Prostacyclin release was evaluated as a biochemical marker. University of Wisconsin solution maintains more than 99% cell viability after rewarming after both 24 and 48 hours of cold storage. After 72 hours, 86.7% of cells were still viable. Preservation with HTK and Euro-Collins solution allowed cell survival for only 24 hours (96.7%, HTK; 49.9%, Euro-Collins), with no viable cells seen after 48 hours. The cold saline-preserved sample showed 57.8% viable cells after 24 hours and 29.7% after 48 hours. No viable cells were detectable after 72 hours. Light microscopy revealed several patterns of both structural damage and intracellular change (nucleus and cytoplasm) in the endothelial monolayer after preservation with HTK, Euro-Collins solution, and cold saline solution. No morphologic alterations were seen in the University of Wisconsin solution group for as long as 72 hours.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Microbiological collaborative studies for quality control in food laboratories: reference material and evaluation of analyst's errors.
Working groups of the Federal Health Office in Germany and of the International Dairy Federation (IDF) have developed a quality assurance system to assess the analyst performance for colony count methods. The experiment design consists of several dilution series produced from a homogeneous sample suspension. Each series contains a number of twofold dilution steps with parallel plates on each level. The structure of this design permits a detailed analysis of the total variance and identification of analysts' methodological errors as single effects. A computer-based interpretation aid may classify the laboratory as working in correspondence with good laboratory practice ('acceptable') or, otherwise, furnishing 'to good' or 'unacceptable' results. Some examples are given for deviation depending on individual faults. Both, internal quality assurance and collaborative studies demand suitable reference samples. The reference material used has to meet certain requirements concerning homogeneity, contamination level and microbiological stability during a period of storage and transport. A naturally contaminated sample material was prepared, which has been used successfully in microbiological collaborative studies.
Animals↗
Two binding sites for naturally occurring inhibitors in mitochondrial and bacterial NADH:ubiquinone oxidoreductase (complex I).
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Animals↗
[Therapeutic interventional sonography].
By means of a review of the literature and basing on own results the possibilities of sonographically guided ontarget therapeutic interventions are disumed. Puncture of pleura, pericardium and in ascites can be performed with maximum safety. Therapeutic drainage of the effusions succeeds to practically 100 per cent. Punctures of custsare performed only if the lesions are symptomatic; sclerosing of renal cysts has a success rate of 65-80%, that of hepatic cysts up to 96%, ovarial and pancreatic cysts up to 90%. Since, however, the latter recur rapidly, permanent success can be rated as amounting to only 7%. Abscesses are punctured in installments or drained, depending on their size, shape and extension. Here, too, success rates achieved via on-target therapy guided by ultrasound are between 80 and 95%. First results obtained with ultrasound-guided on-target cholecystotomy in cases of colecystitis are encouraging; the disease pattern can be improved in at least 63% to 94% of cases, although the rate of complications is 8-12% and hence relatively high. Other techniques are also discussed, such as gastrostomy, nephrostomy, cholangiography and pancreaticography. Local on-target ultrasound-guided tumour therapy, especially of the primary hepatic cell carcinoma using highly concentrated alcohol results in a definitely longer survival period of the treated patients.
Drainage↗
Morphometric X-ray absorptiometry of the spine: correlation in vivo with morphometric radiography. Study of Osteoporotic Fractures Research Group.
The diagnosis of vertebral fractures has been based on lateral thoracic and lumbar spine films and entails the determination of crush, endplate and wedge deformities of the vertebral bodies, generally between T4 and L4. Accuracy and precision of X-ray based morphometry are limited by geometric distortion and other technique-related factors. This paper proposes the use of morphometric X-ray absorptiometry (MXA) as a method which overcomes many of the limitations of morphometric radiography. MXA generates paired anteroposterior and lateral images of the spine using a scanning fan beam geometry that significantly reduces distortions inherent in the cone beam geometry used in conventional X-rays. Intra-observer precision of MXA on 41 subjects aged 65 years and older was 1 mm for vertebral height assessments and 4.7% for vertebral wedge parameters. Linear correlation with vertebral heights and wedge parameters on 32 subjects evaluated by both MXA and morphometric radiography demonstrated a root of the mean squared error of 2.1-2.4 mm and 7.0%, respectively. Vertebral deformities could be identified by MXA. The study documents the feasibility of MXA for the assessment of vertebral deformities. However, further investigation is needed to document the ability of MXA to diagnose prevalent and incident fractures.
Absorptiometry, Photon↗
Secondary myelodysplastic syndrome in multiple myeloma--a study of nine patients with an attempt to detect myeloma patients at risk.
Over a follow-up period of ten years, nine of our 100 patients with multiple myeloma (MM), developed myelodysplastic syndrome (MDS, preleukaemia). MDS occurred 19-156 (median 35) months from the diagnosis of MM. Six patients presented with pancytopenia and no patients had active MM at the time of MDS diagnosis. Three patients were defined as having refractory anaemia (RA) and six as refractory anaemia with excess blasts (RAEB) or RAEB in transformation (RAEBT), according to the FAB classification. The clinical course is characterized by increasing red blood cell and platelet transfusion requirements, recurrent infections and bleeding episodes. All patients, except for one, died within 3 to 8 (median 5) months from MDS diagnosis. The causes of death were sepsis or bleeding; three patients underwent leukaemic transformation. Thus, the clinical course of this small group of myeloma patients who developed secondary MDS (sMDS), was similar to other series of patients with sMDS. Serial bone marrow examinations suggest an initial hypercellular phase, followed by a rapidly evolving preterminal hypocellular marrow. In an attempt to detect MM patients at risk of developing sMDS, the epidemiological (including ethnic), clinical and laboratory data of the 9 MDS patients at the time of the MM presentation were reviewed and compared to the other MM patients. No significant differences were observed between the two groups in most parameters, except for two. All MDS patients were Ashkenazi Jews and no patients of Sepharadic origin developed MDS. Also, no IgA-myeloma patient developed MDS. If these findings are confirmed in a larger series, it may point to subgroups at risk which may require a different approach.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
[The structure and psychodynamics of delusion].
Discussing classical psycho-analytic interpretations of delusion the authors show that neither the notion of "projection" nor the theory of regression to very early stages of ego-formation provide a satisfying explanation for the difficulty of those patients to discern inner world from external reality. An approach to this crucial question rather has to consider the underlying structural differences in order to differentiate between neurotic and psychotic symptom formation. The basis for psychotic symptoms is identified in a deficient mode of symbol-formation impeding certain structural patterns or spheres of conflict from being integrated into the whole of the subject's existence. If required under certain circumstances those "excluded" parts of the personality overwhelm the subjective experience arising as something radically strange and uncanny. A psychotic phenomenon like delusion bears witness of this break down, but at the same time is an attempt to cope with this threatening experience.
Adult↗
Neoplastic transformation dose response of oncogene-transfected rat embryo cells by gamma rays or 6 MeV alpha particles.
We measured a dose-response relationship for induction of neoplastic transformation by 6 MeV alpha particles and 137Cs gamma rays in REC:myc and REC:ras cells, that is, rat embryo cells (REC) transfected with the c-myc or the Ha-ras oncogenes. The 6 MeV alpha particles simulated 222Rn emissions for risk assessment relative to low-LET radiations. The dose of gamma rays was approximately twice that of alpha particles for a neoplastic transformation frequency of 10(-3). The survival of the REC cells containing oncogenes was comparable to that of the commonly used C3H 10T1/2 cells for the same dose, but the former were more refractory to radiation-induced neoplastic transformation. Neoplastic transformation frequency measured in REC cells was 3 times lower than those typically measured in C3H 10T1/2 cells at a gamma-ray dose of 6 Gy, and 5-10 times lower at an alpha-particle dose of 3 Gy.
Alpha Particles↗
[Incidence and differential diagnosis of hyperechoic kidney tumors].
The frequency of kidney tumours was determined in a prospective study of 11,076 consecutive patients investigated sonographically in a department of internal medicine. A further objective of the study was to establish whether the echo characteristics of the renal tumours alone allow sonographic categorization into benign and malignant tumours, how often it is possible to diagnose angiomyolipomas of the kidneys on the basis of sonography alone, and how frequently further imaging techniques and/or invasive methods are necessary. In this patient series, 68 solid renal lesions were detected (0.6%): 15 of the lesions were hypernephroid carcinomas (0.13%) and 28 angiomyolipomas (0.25%). All angiomyolipomas were hyperechoic. In contrast, only 3 of the hyperechoic tumours were hypernephroid carcinomas. Owing to the unequivocal sonographic appearance, 16 out of 28 angiomyolipomas could be diagnosed on the basis of sonography alone. Additional diagnostic measures were necessary for only 12 of these tumours (CT, angiography, intravenous pyelogram, and an operation in 1 patient, who had an angiomyolipoma infiltrating into the vena cava). In contrast to this, computer tomography was necessary in addition for the diagnosis of all malignant tumours, and angiography in 4 cases.
Adult↗
[Electromagnetic fields and health].
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Electromagnetic Fields↗
The gene locus of the proton-translocating NADH: ubiquinone oxidoreductase in Escherichia coli. Organization of the 14 genes and relationship between the derived proteins and subunits of mitochondrial complex I.
The gene locus nuo of the proton-translocating NADH: ubiquinone oxidoreductase in Escherichia coli was identified by means of a DNA probe made by the polymerase chain reaction. The primers used for the reaction were derived from consensus sequences of the NAD(H)-binding subunit of mitochondrial NADH: ubiquinone oxidoreductase and the NAD(+)-reducing hydrogenase of Alcaligenes eutrophus. The nuo locus lies between minutes 49.2 and 49.6 on the E. coli chromosome and contains a cluster of 14 genes. They are bordered upstream by a sequence resembling sigma 70-dependent promoters and downstream by a sequence resembling rho-independent terminators. All 14 proteins derived from the nuo-genes are related to subunits of mitochondrial NADH: ubiquinone oxidoreductase, among which all subunits presumed to bind the substrates and to harbour the redox groups are found, as well as all seven mitochondrially encoded subunits. The E. coli enzyme seems to represent the minimal form of a proton-translocating NADH: ubiquinone oxidoreductase. The gene order in the nuo locus is conserved in comparison with other bacterial genomes and the chloroplast genome of higher plants. To some extent, the gene order correlates with the topological arrangement of the encoded subunits. The conception of modular evolution of NADH: ubiquinone oxidoreductase is further supported by the arrangement of the nuo-genes.
Alcaligenes↗
The role of the proton-pumping and alternative respiratory chain NADH:ubiquinone oxidoreductases in overflow catabolism of Aspergillus niger.
Mitochondria of fungi contain two respiratory chain enzymes concerned with the oxidation of matrix NADH. These are the proton-pumping NADH:ubiquinone oxidoreductase, also called complex I, which has a high affinity for NADH, and a non-proton-pumping NADH:ubiquinone oxidoreductase, called alternative NADH dehydrogenase, which has a low affinity for NADH. The role of these two enzymes in normal and overflow catabolism has been studied in Aspergillus niger. Three strains were investigated, the wild-type 732, the mutant nuo51 that was generated from the wild-type by disrupting the gene of the (51-kDa) NADH-binding subunit of complex I and the citric acid over-producing strain B60 that looses complex I concomitantly with the onset of the over-production. Under standard growth conditions, respiratory energy transduction in the mutant nuo51 was decreased by 40% compared to the parental wild-type and the strain B60. Respiratory electron transfer in the mutant nuo51, however, meets standard catabolic requirements. The intracellular levels of citric acid cycle intermediates in the mutant nuo51 were the same as in the other two strains. Under growth conditions which lead to uncontrolled catabolic flux through glycolysis, a dramatic catabolic overflow occurred in the mutant nuo51. Intracellular levels of citric acid cycle intermediates increased to 20-fold normal levels. The strain B60, likewise lacking complex I under these conditions, excretes large amounts of citrate to moderate the intracellular catabolic overflow.
Aspergillus niger↗
Attempts to define distinct parts of NADH:ubiquinone oxidoreductase (complex I).
The NADH:ubiquinone oxidoreductase (complex I) is made up of a peripheral part and a membrane part. The two parts are arranged perpendicular to each other and give the complex an unusual L-shaped structure. The peripheral part protrudes into the matrix space and constitutes the proximal segment of the electron pathway with the NADH-binding site, the FMN and at least three iron-sulfur clusters. The membrane part constitutes the distal segment of the electron pathway with at least one iron-sulfur cluster and the ubiquinone-binding site. Both parts are assembled separately and relationships of the major structural modules of the two parts with different bacterial enzymes suggest, that both parts also emerged independently in evolution. This assumption is further supported by the conserved order of bacterial complex I genes, which correlates with the topological arrangement of the corresponding subunits in the two parts of complex I.
Animals↗
Bacterial NADH-quinone oxidoreductases: iron-sulfur clusters and related problems.
Many bacteria contain proton-translocating membrane-bound NADH-quinone oxidoreductases (NDH-1), which demonstrate significant genetic, spectral, and kinetic similarity with their mitochondrial counterparts. This review is devoted to the comparative aspects of the iron-sulfur cluster composition of NDH-1 from the most well-studied bacterial systems to date.: Paracoccus denitrificans, Rhodobacter sphaeroides, Escherichia coli, and Thermus thermophilus. These bacterial systems provide useful models for the study of coupling Site I and contain all the essential parts of the electron-transfer and proton-translocating machinery of their eukaryotic counterparts.
Bacterial Proteins↗