Colorectal carcinoma in Poland in 1975 and 1995: not only more,but also different

BACKGROUND AND AIMS: We previously reported that the sole clinicopathological parameters of carcinomas diagnosed in a single institution in 1975 differed from those in patients diagnosed in 1995. The findings might be compatible with the loss of importance of the microsatellite instability of the carcinogenic pathway. MATERIALS AND METHODS: We examined the microsatellite status and selected immunomarkers (Ki-67, p53, BAX) in the archival material from 1975 (n=76) and 1995 (n=105). RESULTS AND CONCLUSION: The distribution of tumors showing no microsatellite instability, low microsatellite instability, and high microsatellite instability in the 2-yearly cohorts was similar (1975: 55.6%, 22.2%, 22.2%; 1995: 60.2%, 20.4%, 19.4%, respectively). The percentage of carcinomas showing microsatellite instability at the APC locus differed significantly (1975: 37.5%; 1995: 21.4%). The typical clinicopathological parameters of carcinomas exhibiting high microsatellite instability were largely shared by the carcinomas demonstrating instability at the APC locus. The carcinomas resected in 1995 more frequently demonstrated high expression of an antiapoptotic protein BAX and a different distribution of their Ki-67 proliferation fraction. The evolution of colorectal carcinoma in Poland also involves qualitative changes, including its genetic background.     

beta-Hydroxyaspartic acid in vitamin K-dependent protein C.

Previous work has shown that the light chain of protein C, an anticoagulant plasma protein, contains an unusual amino acid [Fernlund, P. & Stenflo, J. (1982) J. Biol. Chem. 257, 12170-12179]. To determine the structure of this amino acid a heptapeptide, CMCys-Ile-X-Gly-Leu-Gly-Gly (residues 69-75 in the light chain), was isolated from enzymatic digests of the light chain. According to automatic Edman sequence analysis, 1H NMR spectroscopy, and mass spectrometry the heptapeptide had beta-hydroxyaspartic acid in its third position, which corresponds to position 71 in the light chain of protein C. Analysis of acid and aminopeptidase M hydrolysates of the heptapeptide showed the beta-hydroxyaspartic acid to be the erythro form. Acid hydrolysis of protein C released approximately equal to 1 mol of beta-hydroxyaspartic acid per mol of protein. The function of this amino acid, which, to the best of our knowledge, has not been found previously in proteins, is unknown.     

Ubiquitin not only serves as a tag but also assists degradation by inducing protein unfolding

Protein ubiquitination controls the cellular fate of numerous eukaryotic proteins. Despite its importance, many fundamental questions remain regarding its mechanism. One such question is how ubiquitination alters the biophysical properties of the modified protein and whether these alterations are significant in the cellular context. In this study, we investigate the effects of ubiquitination on the folding thermodynamics and mechanism of various substrates using computational tools and find that ubiquitination changes the thermal stability of modified proteins in a manner relevant to cellular processes. These changes depend on the substrate modification site and on the type of ubiquitination. Ubiquitination of the substrate Ubc7 at the residues that are modified in vivo prior to proteasomal degradation uniquely results in significant thermal destabilization and a local unwinding near the modification site, which indicates that ubiquitination possibly facilitates the unfolding process and improves substrate degradation efficiency. With respect to the substrate p19^4inkd, our results support a synergetic effect of ubiquitination and phosphorylation on the degradation process via enhanced thermal destabilization. Our study implies that, in addition to its known role as a recognition signal, the ubiquitin attachment may be directly involved in the cellular process it regulates by changing the biophysical properties of the substrate.     

Congenital prothrombin defects: they are not only associated with bleeding but also with thrombosis: a new classification is needed

Objective: Congenital prothrombin deficiency is one of the rarest clotting disorders. It is commonly subdivided in Type I defects or cases of ‘true’ prothrombin deficiency characterized by a concomitant decrease in FII activity and antigen and in Type II or dysprothrombinemias, in which FII activity is low but FII antigen is normal or near normal. A bleeding tendency, often a severe one, is the hallmark of the two-defects even though the bleeding is usually less severe in the Type 2 defects or dysprothrombinemias.

Patients and Methods: An extensive search of published cases of prothrombin deficiency was carried out in Pubmed and Scopus. The search started in 2012, after the publication of the first family with dysprothrombinemia and venous thrombosis. A few additional families were found.

Results: Recent studies have demonstrated that the Type 2 defects are heterogeneous. Several heterozygous mutations involving the Arg596 residue of exon 14 have been demonstrated not be associated with a bleeding tendency but, surprisingly, with venous thromboses. Mutations in close areas of prothrombin have failed to show the same pattern.

Conclusions: These observations have required a reclassification of prothrombin defects. To the Type I and Type II defects, a Type III has to be added characterized by the absence of bleeding and the presence of venous thrombosis. It is not clear yet if this special variant of Type II defect is limited to the Arg596 mutations or if other residues may be involved.     

Differences in reactivity to vitamin K administration of the vitamin K-dependent procoagulant factors, protein C and S, and osteocalcin

Vitamin K is a trace nutrient necessary not only for the synthesis of four plasma clotting factors but also the production of two important anticlotting factors, protein C and protein S, and the synthesis of two bone proteins. If protein C and protein S are produced more quickly and/or in higher quantities than four plasma coagulation factors after vitamin K administration, then the result is unfavorable for stopping of hemorrhage. We therefore studied the difference of time dependence of prothrombin procoagulant factors, protein C and S and bone Gla protein after the administration of vitamin K in normal and vitamin K-deficient neonates. Results of our study showed that, on the whole, coagulation factors increased markedly more than anticlotting factors after vitamin K administration. Furthermore, the increase in bone Gla protein was also higher compared with protein C activity, although the detailed mechanism of the difference in reactivity of prothrombin procoagulant factors, protein C and S and bone Gla protein to vitamin K administration is not clear.     

Levels of vitamin K, immunoreactive prothrombin, des-γ-carboxy prothrombin and γ-glutamyl carboxylase activity in hepatocellular carcinoma tissue

Abstract To clarify the mechanism of production of des-γ-carboxy (abnormal) prothrombin (DCP) by hepatocellular carcinoma (HCC), we measured the levels of vitamin K, DCP, immunoreactive prothrombin and the activity of γ-glutamyl carboxylase in liver tissues from HCC patients and in the medium of cultured human hepatoma cells. There was no significant difference in vitamin K (K₁, MK-4) contents between HCC and non-HCC cirrhotic liver tissues. The activity of γ-glutamyl carboxylase per unit amount of endogenous microsomal prothrombin precursor was decreased in HCC tissue compared with non-HCC liver tissue (positive plasma DCP: 335 ± 72 vs 372 ± 67, negative plasma DCP: 370 ± 84 vs 393 ± 56 nmol/min per mg prothrombin precursor, P > 0.05), although the total incorporation of ¹⁴COOH into microsomal precursor protein was higher in the former. By contrast, levels of DCP and immunoreactive prothrombin in HCC tissue were greater ( P > 0.05) than those in non-HCC cirrhotic liver tissue. Furthermore, production of large amounts of immunoreactive prothrombin was observed in human hepatoma cells huH-1 and huH-2, which produced large amounts of DCP. These results suggest that there was excessive synthesis of prothrombin precursors by human HCC tissue and hepatoma cell lines huH-1 and huH-2. Thus, excessive synthesis of prothrombin precursors seems to be the main mechanism of DCP production by HCC.     

Serum adiponectin level is not only decreased in metabolic syndrome but also in borderline metabolic abnormalities

Objective:

Along with the increasing prevalence of obesity and related diseases, particularly atherosclerotic diseases, metabolic syndrome (MetS) is now a common and major public health issue in many countries around the world. Adiponectin, a protein secreted by the adipose tissue, has become recognized as a key player in the development of MetS. These days, not only MetS but also borderline metabolic/physiological abnormalities, such as impaired fasting glucose, high normal blood pressure and high normal plasma cholesterol, have been reported to be risk factors for atherosclerotic disease. Therefore, we undertook this study to determine the relationship between adiponectin and borderline metabolic/physiological abnormalities, as well as MetS.

Design:

A cross-sectional study performed from April 2007 to November 2009.

Subjects:

In 16 892 Japanese adults (10 008 men and 6884 women), we examined the relationship between the serum adiponectin concentration and borderline metabolic/physiological abnormalities or MetS by a questionnaire survey about medical treatment, body size measurement and measurement of laboratory parameters including the serum adiponectin concentration.

Results:

Adiponectin showed a significant negative correlation with the number of MetS components. In subjects without overt diabetes mellitus, hypertension or dyslipidemia, the adiponectin concentration also showed a significant negative correlation with the number of borderline metabolic abnormalities.

Conclusion:

The decrease of circulating adiponectin may start before the development of diabetes mellitus, hypertension, dyslipidemia or MetS. Adiponectin is an important biomarker for reflecting the adverse influence of visceral fat in persons with MetS, and also in these subclinical states.     

Ectopic D-type cyclin expression induces not only DNA replication but also cell division in Arabidopsis trichomes

Although the mechanisms controlling the two cell-cycle checkpoints G(1)-S and G(2)-M are well studied, it remains elusive how they are linked in higher eukaryotes. In animals, D-type cyclins have been implicated in the control of cell-cycle progression in mitotic as well as in endoreduplicating cells. By contrast, we show that the expression of the D-type cyclin CYCD3;1 in endoreduplicating Arabidopsis trichome cells not only induced DNA replication but also cell divisions.     

Blood flow can signal during angiogenesis not only through mechanotransduction,but also by affecting growth factor distribution

Growth factors, such as VEGF, promote the sprouting of new blood vessels. Growth factors are generally produced far from the endothelium, and the transport of these proteins is often assumed to occur through diffusion. When sprouting occurs in a perfused vascular bed, however, interstitial flow is present that can modify protein transport. We recently developed a technique to analyze flow dynamics and vascular remodeling simultaneously in avian embryos. In this study, we extend our technique to model interstitial flow through the porous matrix of the mesenchymal tissue and use this to investigate how flow in the blood vessels affects the distribution of growth factors in the mesenchyme, using VEGF as a prototypical angiogenic molecule. We find that flow controls sprouting location and elongation, both through the direct action of mechanical force and through indirect effects on growth factor distribution. Most importantly, we find that the distribution of VEGF is regulated by interstitial flow, and the effect of diffusion of VEGF is negligible.     

Clinical significance of elevated alpha-fetoprotein (AFP) in patients with chronic hepatitis C, but not hepatocellular carcinoma

BACKGROUND: Although elevated serum alpha-fetoprotein (AFP) is often seen in patients with chronic hepatitis C (CHC), its prevalence, risk factors, and clinical significance remain to be determined. AIMS: The present study assessed the frequency of, the risk factors for, and the clinical significance of elevated AFP in patients with CHC, but not hepatocellular carcinoma. METHODS: This retrospective study utilized systematic chart review and statistical analyses to investigate 357 U.S. patients with CHC from a university medical center and a regional veteran administration medical center. RESULTS: The prevalence of elevated serum AFP (i.e., >/=10.0 microg/L) was 23.0%, including 15.3% (28/183), 24.5% (25/102), and 42.0% (29/69) in patients with chronic hepatitis C and stage 0-II, III, and IV hepatic fibrosis, respectively. After adjusting for age, HCV load, and hepatic steatosis, stage III/IV fibrosis, elevated aspartate aminotransferase (AST), and prolonged prothrombin time as measured by international normalized ratio (INR) remained independently associated with elevated serum AFP in these patients. A serum AFP level of 15.0 microg/L was 22.8% sensitive and 94.5% specific for stage III/IV fibrosis. CONCLUSIONS: In patients with chronic hepatitis C, 23.0% had elevated serum AFP that is independently associated with stage III/IV hepatic fibrosis, elevated level of AST, and prolonged INR.     

Discrimination of normal and abnormal prothrombin and protein C in plasma using a calcium ion-inhibited monoclonal antibody to a common epitope on several vitamin K-dependent proteins

Vitamin K deficiency or administration of vitamin K antagonists results in the biosynthesis of abnormal des-gamma-carboxy forms of the vitamin K-dependent proteins. Monoclonal antibody H-11 binds several vitamin K- dependent proteins at a determinant that includes the first two residues of gamma-carboxyglutamic acid. Antibody H-11 binds fully carboxylated prothrombin and protein C in the presence of EDTA but binding is inhibited by the divalent metal ions, calcium, magnesium, and manganese. By contrast, des-gamma-carboxy prothrombin and protein C bind antibody H-11 the same in the presence of EDTA or calcium ion. Antibody H-11 thus appears to bind a conserved antigenic site containing gamma-carboxyglutamic acid that in the presence of divalent metal ion undergoes a conformational transition. This ability of antibody H-11 to bind des-gamma-carboxy prothrombin and protein C in the presence of calcium ion allowed the development of an immunoassay for these proteins in plasma. Prothrombin and protein C from stably anticoagulated individuals receiving warfarin were characterized by their ability to bind antibody H-11 in the presence of calcium ion. Binding of prothrombin and protein C to antibody H-11 in the presence of calcium correlated temporally with warfarin administration. The inability of calcium ion to inhibit binding of antibody H-11 to abnormal prothrombin and protein C in plasma suggests that the circulating forms of both proteins following warfarin administration cannot undergo the metal ion-dependent conformational transition that includes sequence residues 1 through 12.