A multi-center comparison of diagnostic methods for the biochemical evaluation of suspected mitochondrial disorders.

A multicenter comparison of mitochondrial respiratory chain and complex V enzyme activity tests was performed. The average reproducibility of the enzyme assays is 16% in human muscle samples. In a blinded diagnostic accuracy test in patient fibroblasts and SURF1 knock-out mouse muscle, each lab made the correct diagnosis except for two complex I results. We recommend that enzyme activities be evaluated based on ratios, e.g. with complex IV or citrate synthase activity. In spite of large variations in observed enzyme activities, we show that inter-laboratory comparison of patient sample test results is possible by using normalization against a control sample.

Influence of self-affine roughness on Parsons-Zobel plots for electrical double layers.

In this paper we investigate the dependence of Parsons-Zobel plots on characteristic self-affine roughness parameters of the metal electrode in electrical double layers. Among the roughness amplitude w, the correlation length xi, and roughness exponent H, the latter appears to have the most prominent effect especially for values in the range H<0.5. In addition, with decreasing compact layer thickness the influence of roughness leads to stronger nonlinear behavior of the plots for relatively large electrode potentials. Finally, it is shown that dynamic changes of the electrode roughness (for example by growth on metal films) should be carefully quantified with respect to their influence on the Parson-Zobel plots and related double-layer systems.

Triple-point wetting of van der Waals films on self-affine and mound rough surfaces.

The influence of random self-affine and mound substrate roughness on the wetting scenario of adsorbed van der Waals films is investigated as a function of characteristic roughness parameters. The roughness influence, which leads to triple-point wetting, is calculated by the bending free energy penalty of a solid film picking up the substrate morphology. For self-affine roughness, an increment of the roughness exponent H and/or a decrement of the roughness ratio w/xi (with w being the rms roughness amplitude and xi the in-plane correlation length) leads to a noticeable increment of the thickness of adsorbed solid films. Similarly for mound roughness the thickness dependence of the solid wetting layer on the average mound separation lambda and system correlation length zeta follow the general scenario that smoother substrates (w/zeta<<1 and/or w/lambda<<1) lead to thicker solid films. Nevertheless, in this case the thickness increment is a highly nonmonotonic function of zeta and lambda for lambda

Restoration effects of glucose refeeding on reduced synthesis of albumin and total protein and on disaggregated polyribosomes in liver of starved rats: evidence of a post-transcriptional control mechanism.

Previous studies demonstrated that fasting is accompanied with a reduction of liver protein and albumin synthesis. A protein-deficient diet also leads to a marked change in liver RNA and protein metabolism. Although the reduction of protein synthesis and the disaggregated polyribosomes during fasting can be corrected by a single feeding of protein or a complete amino acid mixture, no or little changes of amino acid concentrations were found in portal blood and liver cytosol of fasted animals as compared to those of the fed group. To determine the effect of glucose on the reduced rate of protein and albumin synthesis of fasted rats, free and membrane-bound polyribosomes were isolated quantitatively from liver of starved rats (42-66 h) at different intervals after a single feeding of glucose and after giving glucose ad libitum for 24 h. (1) The yield of polyribosomal RNA decreased dramatically after a 42- to 66-hour starvation. A glucose refeeding did not change the RNA content. However, the restoration of polyribosome size could be observed rapidly. (2) At various levels of RNA, there was a decreased protein synthesis in fasted animals. However, the synthesis was enhanced after glucose refeeding. The albumin synthesis was also proportionately increased (10-12% of total protein synthesis of membrane-bound polyribosomes). (3) Glucose refeeding had no influence on the content of albumin mRNA sequence and liver RNA. These findings suggest that the effect of glucose on the restoration of protein and albumin synthesis is a sole post-transcriptional event.

Distribution of mRNAS of fibrinogen polypeptides and albumin in free and membrane-bound polyribosomes and induction of alpha-fetoprotein mRNA synthesis during liver regeneration after partial hepatectomy.

To study the effect of regenerative response of the liver following partial hepatectomy on the synthesis of major plasma proteins (secretory proteins), we have determined the sequence contents and the distribution of albumin and fibrinogen polypeptide mRNAs in rat liver at intervals after partial hepatectomy and sham operation. Using a quantitative technique for the isolation of polyribosomes, we demonstrated that the distribution of RNA between free and membrane-bound polyribosomal fraction was unchanged in these experiments. There was no shift in the polyribosomal population to favor free polyribosomes after partial hepatectomy. However, there was a dramatic increase (5-6-fold) of the fibrinogen polypeptide mRNA concentration during the first 24 h after resection. In contrast, the albumin mRNA concentration decreased (2-3-fold). There were no alpha-fetoprotein mRNA sequences detectable in any liver RNA fraction in these experimental animals. In sham-operated rats with intact livers, similar changes of fibrinogen polypeptide and albumin mRNA concentrations as described in regenerating liver after partial hepatectomy, were observed. These results suggest that albumin and fibrinogen synthesis after partial hepatectomy is reciprocally regulated at the mRNA level and represents a nonspecific acute phase response to surgical trauma.

Sequence content of alpha-fetoprotein, albumin and fibrinogen polypeptide mRNAs in different organs, developing tissues and in liver during carcinogenesis in rats.

To investigate the variable gene activities of alpha-fetoprotein, albumin and fibrinogen polypeptides as markers of 'liver specific proteins' in different developing organs or tissues, we have used specific complementary DNA probes to detect and to quantitate alpha-fetoprotein, albumin and fibrinogen polypeptide mRNA, respectively, in RNA fractions, prepared from various tissues of rats at different stages of fetal and postnatal development and from hepatomas induced by diethylnitrosamine. The results indicate that there is no consistent relationship between sequence content of alpha-fetoprotein, albumin and fibrinogen polypeptide mRNA in different developing tissues. Intestines which are like the liver also of endodermal origin do not contain alpha-fetoprotein, albumin and fibrinogen polypeptide mRNAs, while kidneys which are mesodermal in origin were found to be alpha-fetoprotein, albumin and fibrinogen polypeptide mRNA producers in neonatal life. In yolk sac, only alpha-fetoprotein and fibrinogen polypeptide mRNA could be detected. In the liver, the increased level of albumin and fibrinogen polypeptide mRNA during fetal and neonatal development is accompanied with a diminished amount of alpha-fetoprotein mRNA. The neosynthesis of alpha-fetoprotein mRNA in the liver during carcinogenesis occurred without a decreased content of albumin and fibrinogen polypeptide mRNAs. These findings suggest that complex mechanisms of gene regulation are involved in variable gene activities of alpha-fetoprotein, albumin and fibrinogen polypeptides in cells of different organs or tissues developed from a single cell.

Acute effects of ethanol intake on albumin and total protein synthesis in free and membrane-bound polyribosomes of rat liver.

Controversial results have been reported in the last few years concerning the effects of ethanol on hepatic protein synthesis. In most of the studies no distinction has been made between the synthetic capabilities of the polyribosomes and the secretory product of labelled protein by the hepatocytes. In order to assess the influence of a single feeding of ethanol on the synthesis of albumin and total protein by the polyribosomes of rat liver, free and membrane-bound polyribosomes were isolated quantitatively from rats given 4--8 g ethanol per kg body weight 3--5 h before killing. The following results were obtained: (1) No difference was found in yield and size of free and membrane-bound polyribosomes isolated from control and ethanol-treated rats. The abilities to synthesize albumin and total protein were also equal for polyribosomes from both groups. (2) Addition of 1% ethanol to the incubation mixture of protein synthesis lowered albumin and total protein synthesis by 20%. No effect was observed with 0.5% ethanol. (3) Cell sap prepared from ethanol-treated rats contains a factor or factors which stimulate protein synthesis (10--15%). (4) The albumin mRNA sequence content was not changed in free and membrane-bound polyribosomal RNA fractions of ethanol-treated rats as compared to the control animals.

Complement fixation and neutralization RS antibodies in maternal and neonatal sera.

RSV complement fixation antibodies were established in 200 paired maternal and cord blood sera. Geometric mean titres in cord sera were significantly higher than in matermal sera. The differences did not depend on the virus strain used. Half of the paired sera (taken at random) were also submitted to microneutralization tests. No differences were found between geometric mean titres in maternal and cord sera.