Depletion of casein kinase I leads to a NAD(P)(+)/NAD(P)H balance-dependent metabolic adaptation as determined by NMR spectroscopy-metabolomic profile in Kluyveromyces lactis

BACKGROUND

In the Crabtree-negative Kluyveromyces lactis yeast the rag8 mutant is one of nineteen complementation groups constituting the fermentative-deficient model equivalent to the Saccharomyces cerevisiae respiratory petite mutants. These mutants display pleiotropic defects in membrane fatty acids and/or cell walls, osmo-sensitivity and the inability to grow under strictly anaerobic conditions (Rag(-) phenotype). RAG8 is an essential gene coding for the casein kinase I, an evolutionary conserved activity involved in a wide range of cellular processes coordinating morphogenesis and glycolytic flux with glucose/oxygen sensing.

METHODS

A metabolomic approach was performed by NMR spectroscopy to investigate how the broad physiological roles of Rag8, taken as a model for all rag mutants, coordinate cellular responses.

RESULTS

Statistical analysis of metabolomic data showed a significant increase in the level of metabolites in reactions directly involved in the reoxidation of the NAD(P)H in rag8 mutant samples with respect to the wild type ones. We also observed an increased de novo synthesis of nicotinamide adenine dinucleotide. On the contrary, the production of metabolites in pathways leading to the reduction of the cofactors was reduced.

CONCLUSIONS

The changes in metabolite levels in rag8 showed a metabolic adaptation that is determined by the intracellular NAD(P)(+)/NAD(P)H redox balance state.

GENERAL SIGNIFICANCE

The inadequate glycolytic flux of the mutant leads to a reduced/asymmetric distribution of acetyl-CoA to the different cellular compartments with loss of the fatty acid dynamic respiratory/fermentative adaptive balance response.

Enhanced monocyte expression of tissue factor by oxidative stress in patients with antiphospholipid antibodies: effect of antioxidant treatment

In a first study, we performed a cross-sectional analysis of urinary excretion of isoprostanes, IPF(2alpha-III) and (VI), and monocyte tissue factor (TF) antigen and activity between 11 antiphospholipid (APL) antibody-positive patients and 13 APL negative subjects. In a second study, 11 APL positive patients were randomly supplemented either with (n = 6) or without (n = 5) antioxidants (vitamin E at 900 IU day(-1), vitamin C at 2000 mg day(-1)) for 6 weeks. In a third study, TF and superoxide anion were measured in human monocytes incubated with anti-beta(2) glycoprotein 1 (beta(2)GP(1)) or control IgG, either with or without vitamin E. APL-positive patients had higher values of isoprostanes (P < 0.05) and monocyte TF antigen (P = 0.001) and activity (P = 0.0001) than APL-negative subjects. Only in APL positive patients did monocyte TF antigen correlate significantly with IPF(2alpha-III) (rho 0.79; P < 0.003) and IPF(2alpha-VI) (rho = 0.87; P < 0.0001). In patients who received antioxidant supplementation, we found a significant decrease of isoprostanes (P < 0.05) and monocyte TF antigen (P < 0.01) and activity (P < 0.007). In vitro experiments demonstrated that anti-beta(2)GP(1) antibodies dose-dependently enhanced the monocyte production of the superoxide anion and TF, which were significantly inhibited by vitamin E. This study demonstrates that in APL-positive patients, oxidative stress contributes to activate the clotting system via over-expression of monocyte TF. We suggest that anti-beta(2)GP(1) antibodies could play a pivotal role by enhancing the monocyte production of oxygen free radicals.

Three target genes for the transcriptional activator Cat8p of Kluyveromyces lactis: acetyl coenzyme A synthetase genes KlACS1 and KlACS2 and lactate permease gene KlJEN1

The aerobic yeast Kluyveromyces lactis and the predominantly fermentative Saccharomyces cerevisiae share many of the genes encoding the enzymes of carbon and energy metabolism. The physiological features that distinguish the two yeasts appear to result essentially from different organization of regulatory circuits, in particular glucose repression and gluconeogenesis. We have isolated the KlCAT8 gene (a homologue of S. cerevisiae CAT8, encoding a DNA binding protein) as a multicopy suppressor of a fog1 mutation. The Fog1 protein is a homologue of the Snf1 complex components Gal83p, Sip1p, and Sip2p of S. cerevisiae. While CAT8 controls the key enzymes of gluconeogenesis in S. cerevisiae, KlCAT8 of K. lactis does not (I. Georis, J. J. Krijger, K. D. Breunig, and J. Vandenhaute, Mol. Gen. Genet. 264:193-203, 2000). We therefore examined possible targets of KlCat8p. We found that the acetyl coenzyme A synthetase genes, KlACS1 and KlACS2, were specifically regulated by KlCAT8, but very differently from the S. cerevisiae counterparts. KlACS1 was induced by acetate and lactate, while KlACS2 was induced by ethanol, both under the control of KlCAT8. Also, KlJEN1, encoding the lactate-inducible and glucose-repressible lactate permease, was found under a tight control of KlCAT8.

Multiple unfolded states of alcohol dehydrogenase I from Kluyveromyces lactis by guanidinium chloride

Inactivation, dissociation, and unfolding of tetrameric alcohol dehydrogenase I from Kluyveromyces lactis (KlADH I) were investigated using guanidinium chloride (GdmCl) as denaturant. Protein transitions were monitored by enzyme activity, intrinsic fluorescence and gel filtration chromatography. At low denaturant concentrations (less than 0.3 M), reversible transformation of enzyme into tetrameric inactive form occurs. At denaturant concentrations between 0.3 and 0.5 M, the enzyme progressively dissociates into structured monomers through an irreversible reaction. At higher denaturant concentrations, the monomers unfold completely. Refolding studies indicate that a total reactivation occurs only with the enzyme denatured between 0 and 0.3 M GdmCl concentrations. The enzyme denatured at GdmCl concentrations higher than 0.3 M refolds only partially. All together, our results indicate that unfolding of the KlADH I is a multistep process, i.e., inactivation of the structured tetramer, dissociation into partially structured monomers, followed by complete unfolding.

Ethanol tolerance and membrane fatty acid adaptation in adh multiple and null mutants of Kluyveromyces lactis

The effects of ethanol and 1-octanol on growth and fatty acid composition of different strains of Kluyveromyces lactis containing a mutation in the four different alcohol dehydrogenase (KlADH) genes were investigated. In the presence of ethanol and 1-octanol K. lactis reduced the fluidity of its lipids by decreasing the unsaturation index (UI) of its membrane fatty acids. In this way, a direct correlation between nonlethal ethanol concentrations and the decrease in the UI could be observed. At concentrations which totally inhibited cell growth no reaction occurred. These adaptive modifications of the fatty acid pattern of K. lactis to ethanol contrasted with those reported for Saccharomyces cerevisiae and Schizosaccharomyces pombe. Whereas these two yeasts increased the fluidity of their membrane lipids in the presence of ethanol, K. lactis reduced the fluidity (UI) of its lipids. Among the different isogenic adh negative strains tested, the strain containing no ADH (adh0) and that containing only KlADH1 were the most alcohol-sensitive. The strain with only KlADH2 showed nearly the same tolerance as reference strain CBS 2359/152 containing all four ADH genes. This suggests that the KlADH2 product could play an important role in the adaptation/detoxification reactions of K. lactis to high ethanol concentrations.

Isolation and molecular characterization of KlCOX14, a gene of Kluyveromyces lactis encoding a protein necessary for the assembly of the cytochrome oxidase complex

The yeast Kluyveromyces lactis was mutagenized with ethyl methane sulphonate and mutants unable to grow on respiratory carbon sources were isolated. Functional complementation of one of these mutants led to the isolation of KlCOX14, a gene encoding a 64 amino acid protein which is the functional homologue of Saccharomyces cerevisiae Cox14p, a protein necessary for the assembly of the cytochrome oxidase holoenzyme (Glerum et al., 1995). The disruption of KlCOX14 resulted in the absence of the absorption bands relative to cytochromes a and a(3) and in the complete loss of respiratory activity. Klcox14 mutants display the typical phenotype of pet mutants and have a reduced growth rate. In addition, unlike the wild-type, Klcox14 mutants are able to grow by fermentation also in the presence of low glucose. The nucleotide sequence of KlCOX14 has been deposited in the EMBL databank with Accession No. AJ238801.

Molecular analysis of UAS(E), a cis element containing stress response elements responsible for ethanol induction of the KlADH4 gene of Kluyveromyces lactis

KlADH4 is a gene of Kluyveromyces lactis encoding a mitochondrial alcohol dehydrogenase activity, which is specifically induced by ethanol and insensitive to glucose repression. In this work, we report the molecular analysis of UAS(E), an element of the KlADH4 promoter which is essential for the induction of KlADH4 in the presence of ethanol. UAS(E) contains five stress response elements (STREs), which have been found in many genes of Saccharomyces cerevisiae involved in the response of cells to conditions of stress. Whereas KlADH4 is not responsive to stress conditions, the STREs present in UAS(E) seem to play a key role in the induction of the gene by ethanol, a situation that has not been observed in the related yeast S. cerevisiae. Gel retardation experiments showed that STREs in the KlADH4 promoter can bind factor(s) under non-inducing conditions. Moreover, we observed that the RAP1 binding site present in UAS(E) binds KlRap1p.

Use of the KlADH4 promoter for ethanol-dependent production of recombinant human serum albumin in Kluyveromyces lactis

KlADH4 is a gene of Kluyveromyces lactis encoding a mitochondrial alcohol dehydrogenase activity which is specifically induced by ethanol. The promoter of this gene was used for the expression of heterologous proteins in K. lactis, a very promising organism which can be used as an alternative host to Saccharomyces cerevisiae due to its good secretory properties. In this paper we report the ethanol-driven expression in K. lactis of the bacterial beta-glucuronidase and of the human serum albumin (HSA) genes under the control of the KlADH4 promoter. In particular, we studied the extracellular production of recombinant HSA (rHSA) with integrative and replicative vectors and obtained a significant increase in the amount of the protein with multicopy vectors, showing that no limitation of KlADH4 trans-acting factors occurred in the cells. By deletion analysis of the promoter, we identified an element (UASE) which is sufficient for the induction of KlADH4 by ethanol and, when inserted in the respective promoters, allows ethanol-dependent activation of other yeast genes, such as PGK and LAC4. We also analyzed the effect of medium composition on cell growth and protein secretion. A clear improvement in the production of the recombinant protein was achieved by shifting from batch cultures (0.3 g/liter) to fed-batch cultures (1 g/liter) with ethanol as the preferred carbon source.

Enhanced expression of monocyte tissue factor in patients with liver cirrhosis

BACKGROUND

Previous studies have shown that cirrhotic patients produce increased amounts of thrombin but the underlying mechanism is still unknown.

AIMS

To analyse the relation between the rate of thrombin generation and monocyte expression of tissue factor (TF) in cirrhosis.

PATIENTS

Thirty three cirrhotic patients classified as having low (n = 7), moderate (n = 17), or severe (n = 9) liver failure according to Child-Pugh criteria.

METHODS

Prothrombin fragment F1 + 2, monocyte TF activity and antigen, and endotoxaemia were measured in all patients. Polymerase chain reaction (PCR) analysis of TF mRNA was performed in monocytes of five cirrhotic patients.

RESULTS

Prothrombin fragment F1 + 2 was higher in cirrhotic patients than in controls (p < 0.0001). Monocytes from cirrhotic patients had higher TF activity and antigen than those from controls (p < 0.001) with a progressive increase from low to severe liver failure. Monocyte expression of TF was significantly correlated with plasma levels of F1 + 2 (TF activity: r = 0.98, p < 0.0001; TF antigen: r = 0.95, p < 0.0001) and with endotoxaemia (TF activity: r = 0.94, p < 0.0001; TF antigen: r = 0.91, p < 0.0001). PCR analysis of TF mRNA showed TF expression only in three patients with endotoxaemia (more than 15 pg/ml).

CONCLUSIONS

Cirrhotic patients have enhanced expression of TF which could be responsible for clotting activation, suggesting that endotoxaemia might play a pivotal role.

Structural and biochemical studies of alcohol dehydrogenase isozymes from Kluyveromyces lactis

The cytosolic and mitochondrial alcohol dehydrogenases from Kluyveromyces lactis (KlADHs) were purified and characterised. Both the N-terminally blocked cytosolic isozymes, KlADH I and KlADH II, were strictly NAD-dependent and exhibited catalytic properties similar to those previously reported for other yeast ADHs. Conversely, the mitochondrial isozymes, KlADH III and KlADH IV, displayed Ala and Asn, respectively, as N-termini and were able to oxidise at an increased rate primary alcohols with aliphatic chains longer than ethanol, such as propanol, butanol, pentanol and hexanol. Interestingly, the mitochondrial KlADHs, at variance with cytosolic isozymes and the majority of ADHs from other sources, were capable of accepting as a cofactor, and in some case almost equally well, either NAD or NADP. Since Asp-223 of horse liver ADH, thought to be responsible for the selection of NAD as coenzyme, is strictly conserved in all the KlADH isozymes, this amino-acid residue should not be considered critical for the coenzyme discrimination with respect to the other residues lining the coenzyme binding pocket of the mitochondrial isozymes. The relatively low specificity of the mitochondrial KlADHs both toward the alcohols and the cofactor could be explained on the basis of an enhanced flexibility of the corresponding catalytic pockets. An involvement of the mitochondrial KlADH isozymes in the physiological reoxidation of the cytosolic NADPH was also hypothesized. Moreover, both cytosolic and KlADH IV isozymes have an additional cysteine, not involved in zinc binding, that could be responsible for the increased activity in the presence of 2-mercaptoethanol.

The sequence of a 8 kb segment on the right arm of yeast chromosome VII identifies four new open reading frames and the genes for yTAFII145

We report the sequence of a 8,061 bp fragment of Saccharomyces cerevisiae chromosome VII. Five open reading frames (ORFs) of at least 100 amino acids were identified. Three show similarities to the amino-acid sequence of known gene products. ORF G9374 corresponds to the gene coding for the yTAFII145 protein: a TBP-associated factor whose amino-acid sequence was previously reported (Reese et al., 1994). The remaining ORF does not display similarities to known sequences.

Identification of gene encoding a putative RNA-helicase, homologous to SKI2, in chromosome VII of Saccharomyces cerevisiae

We have determined the nucleotide sequence of a segment of VII of the yeast Saccharomyces cerevisiae contained in the cosmid clone pEGH101 for a total of 7 kbp. This sequence contains a large open reading frame (ORF) called G9365, coding for a protein of 1967 amino acids that shows a significant homology with the product of the SKI2 gene of S. cerevisiae and contains domains characteristics of RNA-helicases. The ORF is transcribed in vegetative cells but it is not essential for viability as demonstrated by gene disruption.

Coexistence of anti-phospholipid antibodies and endothelial perturbation in systemic lupus erythematosus patients with ongoing prothrombotic state

BACKGROUND

Anti-phospholipid antibodies (aPLs) were associated with an ongoing prothrombotic state in patients with systemic lupus erythematosus (SLE). Because aPLs are able to shift endothelial function toward procoagulant activity in vitro, we investigated the relationship among aPLs, ongoing prothrombotic state, and endothelial perturbation in SLE patients.

METHODS AND RESULTS

We measured aPLs, anti-EC antibodies, circulating levels of prothrombin fragment F1 + 2 (F1 + 2), tumor necrosis factor-alpha (TNF-alpha), tissue-type plasminogen activator (TPA), and von Willebrand factor (vWF) in 43 SLE patients and 25 healthy subjects. Patients positive for aPLs (n = 23) had a higher prevalence of anti-EC antibodies (P = .02) and higher levels of F1 + 2 (P = .003) than aPL(-) patients. Endothelial perturbation, defined by elevated plasma levels of both TPA and vWF, was significantly associated with aPL positivity (P = .001). F1 + 2 > 1 nmol/L (mean +/- 2 SD of controls) was detected in all but one patient in whom aPL positivity and endothelial perturbation coexisted and in no aPL(+) patient without endothelial perturbation (P = .0039). F1 + 2 was significantly correlated with vWF (rho = .6, P = .004) and TPA (114 = .70, P = .0006) only in aPL(+) patients. Endothelial perturbation was closely associated with high values of TNF-alpha (P = .0001), anti-phospholipid (P = .001), and anti-EC antibodies (P = .012). In 31 patients without a clinical history of thrombosis followed up for 3 years, aPL(+) patients with endothelial perturbation showed higher F1 + 2 and TNF-alpha values than aPL(+) patients without endothelial dysfunction.

CONCLUSIONS

This study shows that in SLE patients, aPL positivity is associated with an ongoing prothrombotic state only in the presence of endothelial perturbation. Our findings also suggest that aPLs and TNF-alpha might cooperate in inducing endothelial perturbation.

Two mitochondrial alcohol dehydrogenase activities of Kluyveromyces lactis are differently expressed during respiration and fermentation

The lactose-utilizing yeast Kluyveromyces lactis is an essentially aerobic organism in which both respiration and fermentation can coexist depending on the sugar concentration. Despite a low fermentative capacity as compared to Saccharomyces cerevisiae, four structural genes encoding alcohol dehydrogenase (ADH) activities are present in this yeast. Two of these activities, namely K1ADH III and K1ADH IV, are located within mitochondria and their presence is dependent on the carbon sources in the medium. In this paper we demonstrate by transcription and activity analysis that KlADH3 is expressed in the presence of low glucose concentrations and in the presence of respiratory carbon sources other than ethanol. Indeed ethanol acts as a strong repressor of this gene. On the other hand, KlADH4 is induced by the presence of ethanol and not by other respiratory carbon sources. We also demonstrate that the presence of KLADH III and KLADH IV in K. lactis cells is dependent on glucose concentration, glucose uptake and the amount of ethanol produced. As a consequence, these activities can be used as markers for the onset of respiratory and fermentative metabolism in this yeast.

Association between low-grade disseminated intravascular coagulation and endotoxemia in patients with liver cirrhosis

BACKGROUND & AIMS

Hyperfibrinolysis may complicate the clinical course of liver cirrhosis. The aim of this study was to evaluate if, in cirrhosis, hyperfibrinolysis is primary or secondary to intravascular clotting activation and if endotoxemia is associated with activation of clotting and/or the fibrinolytic system.

METHODS

Clotting, fibrinolytic indexes, and endotoxemia were studied in 41 cirrhotic patients and 20 healthy subjects.

RESULTS

Twenty-seven cirrhotic patients (66%) had high plasma levels of prothrombin fragment F1 + 2, a marker of thrombin generation. Nineteen patients had elevated values of D-dimer, a marker of fibrinolysis in vivo. All patients with high values of D-dimer also had high values of prothrombin fragment F1 + 2. Endotoxemia was elevated in patients with severe liver failure and significantly correlated to prothrombin fragment F1 + 2. Thirty patients were treated for 7 days either with standard therapy (n = 15) or with standard therapy plus nonabsorbable antibiotics (n = 15). Although standard therapy did not significantly change laboratory indexes, a significant reduction of endotoxemia, prothrombin fragment F1 + 2, and D-dimer was found in those patients who received the combined treatment.

CONCLUSIONS

This study shows that, in cirrhotic patients, hyperfibrinolysis is not a primary phenomenon but occurs as a consequence of clotting activation and that endotoxemia might play a pathophysiological role.

Prognostic value of clotting and fibrinolytic systems in a follow-up of 165 liver cirrhotic patients. CALC Group

One hundred sixty-five patients with cirrhosis diagnosed by needle liver biopsy were followed for 2 years to evaluate the relation between clotting factors and survival. Patients with spontaneous bacterial peritonitis, hepatic carcinoma, and cholestatic liver diseases were excluded. Patients were classified as A (n = 34), B (n = 75), or C (n = 56) according to Child-Pugh criteria. During the follow-up 45 patients died of liver failure or gastrointestinal hemorrhage. Nonsurvivor patients had significantly higher values of bilirubin and D-dimer, a marker of fibrinolysis in vivo, lower values of albumin, prothrombin activity, fibrinogen, prekallikrein, factor VII, and a more prolonged activated partial thromboplastin time than survivors. All these variables and Child-Pugh classification were significantly associated with survival in a univariate analysis. Multivariate analysis (Cox's model) showed that only prekallikrein and factor VII were independently predictors of survival. Ninety-three percent of patients with prekallikrein values < 32% died within 32 months of follow-up, whereas factor VII < 34% identified 93% of patients who died within 10 months of follow-up. This study suggests that factor VII is an early predictor of survival and may be a useful test to better identify cirrhotic patients who should be candidates for liver transplantation.

Glucose metabolism and ethanol production in adh multiple and null mutants of Kluyveromyces lactis

Four genes coding for alcohol dehydrogenase (ADH) activities were identified in Kluyveromyces lactis. Due to the presence in this yeast of multiple ADH isozymes, mutants in the individual genes constructed by gene replacement yielded no clear phenotype. We crossed these mutants and developed a screening procedure which allowed us to identify strains lacking several ADH activities. The analysis of the adh triple mutants revealed that each activity confers to the cell the ability to grow on ethanol as the sole carbon source. On the contrary, adh null strains failed to grow on this substrate, indicating that no other important ADH activities are present in K. lactis cells. In the adh null mutants we also found a residual production of ethanol, as has been reported to be the case in Saccharomyces cerevisiae. This production showed a ten-fold increase when the K1ADHI activity was reintroduced in the null mutant and cells were cultivated under oxygen-limiting conditions. Differently from S. cerevisiae, glycerol is poorly accumulated in K. lactis adh null mutants.

1-year survey of patients with advanced liver cirrhosis. Prognostic value of clinical and laboratory indexes identified by the Cox regression model

The relation between coagulation indexes and survival rate was studied and analyzed in 46 patients with advanced liver cirrhosis (grade B and C Child-Pugh Classification), during a follow-up of 1 year. Twenty-four patients (52%) died of liver failure or fatal haemorrhage within 12 months of follow-up. Prothrombin activity, fibrinogen, fibrin(ogen) degradation products, prekallikrein and factor VII, serum bilirubin, and the degree of liver insufficiency, scored by Child-Pugh classification, proved to be significantly correlated with survival by univariate analysis. A multivariate survival analysis (Cox regression model) disclosed two variables, prekallikrein and factor VII, that predicted survival. The rate ratios of death increased to 2.8 and 7.6 with values of prekallikrein < 26% and factor VII < 39%, respectively. This study shows that some simple laboratory tests exploring the clotting system may identify patients with poor prognosis in severe liver failure.

Ethanol-induced and glucose-insensitive alcohol dehydrogenase activity in the yeast Kluyveromyces lactis

The alcohol dehydrogenase (ADH) system in the yeast Kluyveromyces lactis is encoded by four ADH genes. In this paper we report evidence that at least three of these genes are transcribed and translated into protein. KIADH1 and KIADH2, which encode cytoplasmic activities, are preferentially expressed in glucose-grown cells with respect to ethanol-grown cells. KIADH4, which encodes one of the two activities localized within mitochondria, is induced at the transcriptional level in the presence of ethanol as is the ADH2 gene in Saccharomyces cerevisiae. However the regulation of the expression of the K. lactis gene is completely different from that of ADH2 and of other known ADH genes in that KIADH4 is insensitive to glucose repression and is not expressed on non-fermentable carbon sources other than ethanol. This kind of regulation can be clearly observed in non-fermenting strains, where the induction of KIADH4 is dependent on the addition of ethanol to the medium. On the contrary, in fermenting strains KIADH4 is always induced by ethanol or acetaldehyde produced endocellularly and this results in constitutive expression of the gene also in the presence of glucose. The mitochondrial localization of the activity encoded by KIADH4 and the peculiar regulation of this gene could be related to the fact that K. lactis is a petite negative yeast in which some mitochondrial functions seem to be essential for cell viability.

Methods for detecting lupus anticoagulants and their relation to thrombosis and miscarriage in patients with systemic lupus erythematosus

AIMS

To examine the sensitivity and specificity to past thrombotic events of four different coagulation tests, which screen for lupus anticoagulant (LA), and of anticardiolipin antibodies in patients with systemic lupus erythematosus.

METHODS

Fifty three consecutive patients with systemic lupus erythematosus were studied of whom three males and 21 females, aged 21-60 years, had a history of venous and arterial thrombosis, or miscarriage, or both. Activated partial thromboplastin time (aPTT), dilute Russell's viper venom time (dRVVT), kaolin clotting time (KCT), dilute aPTT and the circulating titre of anticardiolipin antibodies were investigated in the two groups of patients and in 20 healthy control subjects.

RESULTS

The prolonged dilute aPTT was more sensitive to thromboses or miscarriages, or both than dRVVT (p less than 0.05), KCT (p less than 0.01), and aPTT (p less than 0.001). No significant differences in specificity were found among aPTT (100%), dRVVT (93%), KCT (93%) and dilute aPTT (86.2%); but aPTT and dRVVT were significantly more specific (p less than 0.01, p less than 0.05, respectively) than anticardiolipin antibodies.

CONCLUSIONS

The study shows a strong association between lupus anticoagulant and thrombosis when a very sensitive test such as the dilute aPTT is used. The combination of this assay with a very specific test such as dRVVT might enable patients with SLE at high risk of thrombosis to be identified.

Effect of oral defibrotide on tissue-plasminogen activator and tissue-plasminogen activator inhibitor balance

Defibrotide, a polydeoxyribonucleotide of mammalian origin, has been shown to reduce the blood level of the plasminogen activator inhibitor, and so to increase the activity of tissue plasminogen activator without any adverse effect. A randomized, double-blind, placebo-controlled study has been done in 22 patients, 14 with peripheral vascular disease, 6 with coronary heart disease and 2 with cerebrovascular disease. Patients were given defibrotide 400 mg b.d. or identical placebo for 30 days and the parameters of fibrinolysis were evaluated before and after the treatment. A significant increase in tissue plasminogen activator activity at rest and after venostasis was observed after defibrotide; tissue plasminogen activator antigen at rest and after venostasis was not affected by either treatment. Defibrotide significantly reduced plasminogen activator inhibitor activity and antigen at rest. Only one patient complained of gastric pain after placebo treatment. The study shows that defibrotide has profibrinolytic property and that it could be used to explore the role of plasminogen activator inhibitor in venous and arterial thrombosis.

Hyperfibrinolysis increases the risk of gastrointestinal hemorrhage in patients with advanced cirrhosis

Sixty-one patients with different degrees of liver failure, 23 with Child-Pugh class B and 38 with Child-Pugh class C, were studied and observed for 3 yr. Coagulation index analysis showed significantly lower values of prothrombin activity, more prolonged activated partial thromboplastin time, higher bilirubin and fibrinogen degradation products values in class C patients. Among all patients, 28 had fibrinogen degradation products values greater than 10 micrograms/ml, and in these patients a hyperfibrinolytic state was confirmed by higher values of circulating plasminogen activator antigen (17.3 +/- 8.7 ng/ml vs. 5.41 +/- 1.9 ng/ml; p less than 0.0001) and activity (6.6 +/- 2.1 IU/ml vs. 1.92 +/- 1.12 IU/ml; p less than 0.0001) and significantly lower plasminogen activator inhibitor antigen (6.4 +/- 3.5 ng/ml vs. 15.8 +/- 5.6 ng/ml; p less than 0.0001) and activity (3.6 +/- 2.2 IU/ml vs. 8.5 +/- 3.9 IU/ml; p less than 0.0001). Patients with positive fibrinogen degradation products had higher serum bilirubin (6 +/- 4 mg/dl vs. 2 +/- 2 mg/dl; p less than 0.0001) and lower fibrinogen (156 +/- 52 mg/dl vs. 194 +/- 62 mg/dl; p less than 0.02) than patients without hyperfibrinolysis. During the follow-up period, 41 patients died, 22 from fatal gastrointestinal hemorrhage and 19 from liver failure. Thirty patients experienced fatal (22 patients) and nonfatal (8 patients) gastrointestinal hemorrhage. Patients with positive fibrinogen degradation products or class C had a higher risk of gastrointestinal bleeding than patients with negative fibrinogen degradation products (odds ratio = 8) or class B (odds ratio = 3.5), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Clotting abnormalities in chronic liver disease

In patients with chronic liver disease (CLD), several clotting changes can be observed. The most frequent abnormality is the reduced synthesis of many clotting factors, including vitamin-K-dependent and vitamin-K-independent ones. A low platelet count is another frequent feature of patients with CLD, which, however, is not always associated with the prolongation of bleeding time. Hyperfibrinolytic syndrome is usually seen in patients with decompensated state, and may further deteriorate the clotting abnormalities and favor bleeding complications. The assessment of the clotting system may be a useful approach to evaluate liver function and predict prognosis of patients with CLD.

Two genes encoding putative mitochondrial alcohol dehydrogenases are present in the yeast Kluyveromyces lactis

Four structural genes encoding isozymes of the alcohol dehydrogenase (ADH) system in the yeast Kluyveromyces lactis have been identified by hybridization to ADH2 DNA probes from Saccharomyces cerevisiae. In this paper we report on the isolation of KlADH4 and the complete sequencing of KlADH3 and KlADH4, two genes which show high homology to KlADH1, the ADH gene previously isolated in K. lactis, and to the ADH genes of S. cerevisiae. When compared with KlADH1, both KlADH3 and KlADH4 encode amino-terminal extensions which show the characteristics of the mitochondrial targeting sequences. These extensions are poorly conserved both at the nucleotide and the amino acid level. Surprisingly, the KlADH4 extension shows a higher identity at the amino acid level to the one encoded by ADH3 of S. cerevisiae than to the KlADH3 presequence. KlADH3 and KlADH4, in contrast to the ADH3 gene of S. cerevisiae, show a strong bias in the choice of codons.

Specificity and sensitivity of diluted aPTT and anticardiolipin antibodies towards thrombosis and miscarriages in patients with systemic lupus erythematosus

In 36 patients suffering from systemic lupus erythematosus (SLE), lupus anticoagulant (LA), as assessed by aPTT and diluted aPTT, and anticardiolipin antibodies (aCL) were studied. 14 patients, had a clinical history complicated by thrombosis and/or miscarriages. Among patients with thrombosis LA was positive in 42% and in 100% of patients when assessed by aPTT and diluted aPTT respectively; aCL were positive in 85.7% of patients. Among patients without a clinical history of thrombosis, 1 had prolonged aPTT, 3 had prolonged diluted aPTT and 5 had aCL positivity. Diluted aPTT was more sensitive than aPTT and aCL (p less than 0.01) to thrombosis and miscarriages; specificity to thrombosis and miscarriages ranged from 77.3% for aCL and 86.4% for diluted aPTT to 95.5% for aPTT but not significant differences were found. The study suggests that LA, as assessed by a sensitive test like diluted aPTT, is strongly associated to thrombosis and should therefore be considered an important risk factor.

The alcohol dehydrogenase system in the yeast, Kluyveromyces lactis

We have studied the alcohol dehydrogenase (ADH) system in the yeast Kluyveromyces lactis. Southern hybridization to the Saccharomyces cerevisiae ADH2 gene indicates four probable structural ADH genes in K. lactis. Two of these genes have been isolated from a genomic bank by hybridization to ADH2. The nucleotide sequence of one of these genes shows 80% and 50% sequence identity to the ADH genes of S. cerevisiae and Schizosaccharomyces pombe respectively. One K. lactis ADH gene is preferentially expressed in glucose-grown cells and, in analogy to S. cerevisiae, was named K1ADH1. The other gene, homologous to K1ADH1 in sequence, shows an amino-terminal extension which displays all of the characteristics of a mitochondrial targeting presequence. We named this gene K1ADH3. The two genes have been localized on different chromosomes by Southern hybridization to an orthogonal-field-alternation gel electrophoresis-resolved K. lactis genome. ADH activities resolved by gel electrophoresis revealed several ADH isozymes which are differently expressed in K. lactis cells depending on the carbon source.

Tissue plasminogen activator inhibitor in patients with systemic lupus erythematosus and thrombosis

OBJECTIVE

To examine the relations among tissue plasminogen activator antigen, plasminogen activator inhibitor, the lupus anticoagulant, and anticardiolipin antibodies in patients with systemic lupus erythematosus.

DESIGN

Prospective study of blood samples (a) from selected patients with systemic lupus erythematosus whose disease was and was not complicated by a history of thrombosis or recurrent abortions, or both, and (b) from a series of healthy controls with a similar age and sex distribution.

SETTING

University based medical clinic.

SUBJECTS

23 Patients with definite systemic lupus erythematosus (American Rheumatism Association criteria), of whom 11 (eight women) aged 26-51 had a history of thrombosis or recurrent abortions, or both, and 12 (10 women) aged 23-53 had no such history. 15 Healthy subjects (10 women) aged 25-58 served as controls.

MAIN OUTCOME MEASURES

Tissue plasminogen activator concentrations, plasminogen activator inhibitor activities, detection of the lupus anticoagulant, and values of anticardiolipin antibodies in the two groups of patients and in the patients with a history of thrombosis or abortions compared with controls. Other measurements included concentrations of proteins that are known to change during the acute phase of systemic lupus erythematosus--namely, fibrinogen, C3 and C4, and C reactive protein.

RESULTS

Patients with a history of thrombosis or abortions, or both, had significantly higher values of tissue plasminogen activator and plasminogen activator inhibitor than patients with no such history. A significant correlation between tissue plasminogen activator and plasminogen activator inhibitor (r = 0.80) was found only in the patients with a history of complications of their disease. The lupus anticoagulant was detected in six of the 11 patients with a history of thrombosis or abortions when tested by measuring the activated partial thromboplastin time but was found in all 11 patients when tested by measuring the diluted activated partial thromboplastin time. Nine of these 11 patients had raised values of anticardiolipin antibodies. The findings showed no relation to the activity of the disease.

CONCLUSIONS

A significant correlation between tissue plasminogen activator concentrations and plasminogen activator inhibitor activities was found only in patients whose systemic lupus erythematosus was complicated by a history of thrombosis or recurrent abortions. The findings show that these patients have raised plasminogen activator inhibitor activities, and the frequent association between these raised activities and the presence of the lupus anticoagulant suggests that the two may be linked.

Dilute aPTT prolongation by antiphospholipid antibodies in patients with liver cirrhosis

The behaviour of aPTT, as assessed by standard or diluted phospholipid mixture, was investigated in 20 patients suffering from liver cirrhosis. Standard aPTT was prolonged in 13 but it was corrected by 1:1 mixture with normal plasma. Dilute aPTT performed in samples mixed 1:1 with normal plasma and calculated by the difference in time between 1:80 and 1:5 phospholipid mixture was prolonged in 9 patients, who had also significantly higher titre of anticardiolipin antibodies (p less than 0.005). Unlike patients' plasma with normal dilute aPTT, the addition of 0.05 M PC/PS liposomes to patient's plasma with prolonged dilute aPTT significantly shortened dilute aPTT (p less than 0.001). This study shows the presence of antiphospholipid antibodies in some patients with liver cirrhosis; this seems to be responsible for the prolongation of dilute aPTT.

Interrelation between factor VII, prekallikrein, and hyperfibrinolysis in advanced cirrhosis

Factor VII and prekallikrein activities were studied in 37 patients with liver cirrhosis who were in a decompensated state. Sixteen of them died 30-70 days after admission; 21 survived and were discharged after 30-80 days. Seven who died and six survivors had signs of hyperfibrinolysis: factor VII activity differentiated the two groups independently of the presence of hyperfibrinolysis. The presence of hyperfibrinolysis significantly reduced prekallikrein activity, which did not differentiate clearly survivors from non-survivors. Long term follow up of survivors showed a good correlation between factor VII and prekallikrein activities with long term survival. Hyperfibrinolysis seemed to influence the clinical course of patients: 87% of patients with hyperfibrinolysis who died had fatal haemorrhagic episodes. Low factor VII activity may be a precursor of terminal liver insufficiency.

Inhibition of tissue plasminogen activator inhibitor by defibrotide in atherosclerotic patients

Defibrotide, an antithrombotic drug, was previously shown to activate fibrinolysis. In order to elucidate the relationship between defibrotide treatment and fibrinolysis, ten atherosclerotic patients were given 1200 mg/day defibrotide intravenously for 7 days and then 400 mg/day intramuscularly for another 20 days. t-PA antigen assessed before and after venous occlusion was not affected by the treatment. Tissue PAI activity significantly decreased and t-PA activity, measured after venous occlusion, increased after 8 and 28 days of treatment; both these changes disappeared after defibrotide was discontinued. No particular side effects were detected throughout the investigation. The study suggests that defibrotide increases t-PA activity by reducing PAI activity.

A gene-cloning system for Kluyveromyces lactis and isolation of a chromosomal gene required for killer toxin production

A transformation system derived from the circular plasmid pKD1 has been developed for Kluyveromyces lactis. The principle is essentially equivalent to that of the 2 microns/Saccharomyces cerevisiae transformation system. The main features of the system are presented. Using a pKD1-based DNA bank of K. lactis, the KEX1 gene involved in the killer system was isolated by complementation.

Hageman factor, high molecular weight kininogen, and prekallikrein in chronic liver disease

The activities of Hageman factor, high molecular weight kininogen (HMWK), and prekallikrein were studied in patients who had chronic active hepatitis and cirrhosis. Serum HMWK and prekallikrein activities were decreased in chronic active hepatitis and cirrhosis, but Hageman factor activity was low in cirrhosis only. The reduction of prekallikrein, HMWK, and Hageman factor was dependent on the degree of liver failure. Similar prekallikrein values were found in serum samples, activated or not, with an excess of Hageman factor and HMWK, which suggests that the decrease of prekallikrein in liver disease is not influenced by the simultaneous decrease of Hageman factor and HMWK.

Sequence organization of the circular plasmid pKD1 from the yeast Kluyveromyces drosophilarum

pKD1 is the only circular plasmid known in the genus Kluyveromyces. Nucleotide sequence analysis has revealed that this 4757 base-pairs long plasmid contained three major open reading frames, A, B, and C, and a pair of inverted repeats of 346 base-pairs. The molecule exists in two isomeric forms generated by internal recombination at these repeats. The functional organization of pKD1 genome appears to be quite analogous to that of the 2u plasmid of Saccharomyces cerevisiae. There is however little homology of sequences between these plasmids, except that the gene A has a dispersed but significant homology with the FLP recombinase gene of the 2u plasmid. S.cerevisiae cells can be transformed by derivatives of pKD1 carrying URA3 gene as a selection marker.

Prekallikrein and factor VII as prognostic indexes of liver failure

Normotest, serum albumin, prekallikrein (Prekk), and Factor VII plasma activity were investigated in 64 patients with chronic liver disease--13 with type I chronic active hepatitis (CAH), 10 with type II CAH, 16 with compensated liver cirrhosis (LC), and 25 with decompensated LC--and in 20 matched-for-age healthy individuals. All of these blood parameters were reduced significantly as a result of liver damage. Patients with type II CAH and compensated LC had similar blood coagulation values. Eight decompensated LC patients, who died 30 to 45 days after the last blood coagulation parameter measurements, showed significantly low Prekk and Factor VII values compared with eight matched for sex and age survivors of decompensated LC. Prekk and Factor VII values of nonsurvivors did not overlap those of the survivors. This striking difference was not detected if Prekk and Factor VII were studied 2 to 4 months before death. These data suggest that Prekk and Factor VII are very sensitive to liver damage and could be useful prognostic indexes of liver insufficiency.

Analysis of a 1.6-micron circular plasmid from the yeast Kluyveromyces drosophilarum: structure and molecular dimorphism

A new plasmid has been found in the yeast Kluyveromyces drosophilarum. It is a double-stranded circular DNA, 1.6 micron in length (4.8 kilobase pairs). As in the case of Saccharomyces 2 mu circles, this plasmid occurs in two isomeric forms corresponding to the inversion of a segment between two 346-bp-long inverted repeats within the molecule. Each form has been separately cloned into bacterial plasmids. The new yeast plasmid, called pKD1, contains sequences that allow its replication in Saccharomyces cerevisiae.

Correlation between hepatic blood flow and coagulation indices in chronic active hepatitis and liver cirrhosis patients

Hepatic blood flow (HBF) has been reported to reflect liver cell mass. HBF was studied in 21 patients with chronic active hepatitis (CAH) and in 20 patients with liver cirrhosis (LC). It was correlated with such indices of liver protein synthesis as serum albumin, Normotest, plasma activity of antithrombin III, prekallikrein, alpha 2-antiplasmin and plasminogen. No correlation between HBF and the examined parameters was seen in CAH. HBF correlated with all the indices of liver protein synthesis in LC, thus suggesting that serum albumin, antithrombin III, Normotest, prekallikrein, plasminogen, and alpha 2-antiplasmin could reflect the residual liver cell mass in LC.