Quantifying the Mechanical Properties of Materials and the Process of Elastic-Plastic Deformation under External Stress on Material

The paper solves the problem of the nonexistence of a new method for calculation of dynamics of stress-deformation states of deformation tool-material systems including the construction of stress-strain diagrams. The presented solution focuses on explaining the mechanical behavior of materials after cutting by abrasive waterjet technology (AWJ), especially from the point of view of generated surface topography. AWJ is a flexible tool accurately responding to the mechanical resistance of the material according to the accurately determined shape and roughness of machined surfaces. From the surface topography, it is possible to resolve the transition from ideally elastic to quasi-elastic and plastic stress-strain states. For detecting the surface structure, an optical profilometer was used. Based on the analysis of experimental measurements and the results of analytical studies, a mathematical-physical model was created and an exact method of acquiring the equivalents of mechanical parameters from the topography of surfaces generated by abrasive waterjet cutting and external stress in general was determined. The results of the new approach to the construction of stress-strain diagrams are presented. The calculated values agreed very well with those obtained by a certified laboratory VÚHŽ.     

Postoperative Bleeding Complications after Gastric Cancer Surgery in Patients Receiving Anticoagulation and/or Antiplatelet Agents

Background

Perioperative antithrombotic treatment for gastric cancer patients receiving chronic anticoagulation and/or antiplatelet agents requires an understanding of potential bleeding and thromboembolic risks. However, no study has examined the safety aspects of perioperative antithrombotic treatment during radical gastrectomy. This study sought to evaluate postoperative bleeding and thromboembolic complications after radical gastrectomy in patients undergoing perioperative antithrombotic treatment.

Methods

The medical records of patient treated by radical gastrectomy from January 2006 to December 2010 were retrospectively reviewed. Those in the thromboprophylaxis group had received one of three regimens of perioperative antithrombotic treatment according to the clinical indications of chronic anticoagulation and/or antiplatelet agents and several published evidence-based recommendations: (1) bridging therapy with unfractionated heparin; (2) continuation of aspirin; or (3) both 1 and 2. multivariate analysis was used to identify risk factors for postoperative bleeding complications after radical gastrectomy.

Results

During the study period, 340 patients underwent radical gastrectomy. Of these, 62 patients received perioperative antithrombotic treatment; this thromboprophylaxis group had a significantly higher postoperative bleeding rate (8.1 vs. 0.7?%, P?=?0.003). However, other complications, including thromboembolic events, were similar in the two study groups. Multivariate analysis revealed that perioperative antithrombotic treatment was the only independent risk factor of postoperative bleeding complications after radical gastrectomy (odds ratio, 8.53; 95?% confidence interval, 1.47?C49.39; P?=?0.017).

Conclusions

Perioperative antithrombotic treatment is an independent risk factor of postoperative bleeding complications in patients with gastric cancer undergoing radical gastrectomy, although such treatment was effective in preventing postoperative thromboembolic events.     

A case of spontaneous splenic rupture during chemotherapy for B-cell chronic lymphoid leukemia

Spontaneous splenic rupture is a life-threatening disease and an important differential diagnosis of acute abdomen. Early clinical diagnosis and rapid intervention is required to ensure patient survival. Spontaneous splenic rupture may be induced by hematological, inflammatory or infiltrative diseases affecting the spleen. Splenomegaly may also significantly increase the risk of rupture. Other contributory factors include male, adulthood, rapid growth of the spleen and splenic abscess. Here, we present the case of a 69-year-old man who was undergoing chemotherapy for B-cell chronic lymphoid leukemia. He was admitted to our hospital after he suddenly developed persistent upper abdominal pain. Computed tomography and ultrasonography revealed accumulation of free fluid in and around the spleen. He was diagnosed as having spontaneous splenic rupture and an emergency operation was performed. During the operation, we found a massively enlarged spleen with several capsular tears, and performed a splenectomy. The patient made a good recovery. Pathological examination revealed that the spleen was infiltrated by CD20-, CD5- and CD23-positive lymphoid blasts. We encountered a case of spontaneous splenic rupture in a patient receiving chemotherapy for exacerbating B-cell chronic lymphoid leukemia. In a case of abdominal pain of acute onset in patients with hematological disease, spontaneous splenic rupture should be suspected.     

Geographic differentiation of polymorphism in the Plasmodium falciparum malaria vaccine candidate gene SERA5

SERA5 is regarded as a promising malaria vaccine candidate of the most virulent human malaria parasite Plasmodium falciparum. SERA5 is a 120 kDa abundantly expressed blood-stage protein containing a papain-like protease. Since substantial polymorphism in blood-stage vaccine candidates may potentially limit their efficacy, it is imperative to fully investigate polymorphism of the SERA5 gene (sera5). In this study, we performed evolutionary and population genetic analysis of sera5. The level of inter-species divergence (kS=0.076) between P. falciparum and Plasmodium reichenowi, a closely related chimpanzee malaria parasite is comparable to that of housekeeping protein genes. A signature of purifying selection was detected in the proenzyme and enzyme domains. Analysis of 445 near full-length P. falciparum sera5 sequences from nine countries in Africa, Southeast Asia, Oceania and South America revealed extensive variations in the number of octamer repeat (OR) and serine repeat (SR) regions as well as substantial level of single nucleotide polymorphism (SNP) in non-repeat regions (2562 bp). Remarkably, a 14 amino acid sequence of SERA5 (amino acids 59-72) that is known to be the in vitro target of parasite growth inhibitory antibodies was found to be perfectly conserved in all 445 worldwide isolates of P. falciparum evaluated. Unlike other major vaccine target antigen genes such as merozoite surface protein-1, apical membrane antigen-1 or circumsporozoite protein, no strong evidence for positive selection was detected for SNPs in the non-repeat regions of sera5. A biased geographical distribution was observed in SNPs as well as in the haplotypes of the sera5 OR and SR regions. In Africa, OR- and SR-haplotypes with low frequency (<5%) and SNPs with minor allele frequency (<5%) were abundant and were mostly continent-specific. Consistently, significant genetic differentiation, assessed by the Wright's fixation index (Fst) of inter-population variance in allele frequencies, was detected for SNPs and both OR- and SR-haplotypes among almost all parasite populations. The exception was parasite populations between Tanzania and Ghana, suggesting frequent gene flow in Africa. The present study points to the importance of investigating whether biased geographical distribution for SNPs and repeat variants in the OR and SR regions affect the reactivity of human serum antibodies to variants.     

Stimulation by follicle-stimulating hormone of synthesis of lactate by Sertoli cells from rat testis

Sertoli cells from rats aged 16 days were cultured in defined medium for 2 days and then treated by addition of fresh medium containing various hormones (treated) or saline (control). The concentration of lactate in the medium was measured as a function of time. The production of lactate measured under these conditions was increased by addition of FSH to the medium. For NIH FSH (13 and 14), ED50 for stimulation of lactate production was approximately 0.05 micrograms/ml. Stimulation was also seen with LH and TSH (ED50, 0.8 micrograms/ml for both hormones). Reasons are given for believing that TSH may possess the inherent capacity to stimulate production of lactate in contrast to LH, which appears to act only by way of contaminating traces of FSH. Dibutyryl cAMP also stimulates lactate production by Sertoli cells. Other hormones tested, including androgens, were without effect. When production of lactate by Sertoli cells was compared with the maximal consumption by spermatids in vitro, it became apparent that Sertoli cells may provide the major source of metabolic substrate for spermatids in the form of lactate. Stimulation of lactate production by FSH was inhibited by puromycin, cycloheximide, and actinomycin D. Evidently this response requires synthesis of new protein and RNA. This effect of FSH may be important in the regulation of spermatogenesis.     

The construction of an EST database for Bombyx mori and its application

To build a foundation for the complete genome analysis of Bombyx mori, we have constructed an EST database. Because gene expression patterns deeply depend on tissues as well as developmental stages, we analyzed many cDNA libraries prepared from various tissues and different developmental stages to cover the entire set of Bombyx genes. So far, the Bombyx EST database contains 35,000 ESTs from 36 cDNA libraries, which are grouped into approximately 11,000 nonredundant ESTs with the average length of 1.25 kb. The comparison with FlyBase suggests that the present EST database, SilkBase, covers >55% of all genes of Bombyx. The fraction of library-specific ESTs in each cDNA library indicates that we have not yet reached saturation, showing the validity of our strategy for constructing an EST database to cover all genes. To tackle the coming saturation problem, we have checked two methods, subtraction and normalization, to increase coverage and decrease the number of housekeeping genes, resulting in a 5-11% increase of library-specific ESTs. The identification of a number of genes and comprehensive cloning of gene families have already emerged from the SilkBase search. Direct links of SilkBase with FlyBase and WormBase provide ready identification of candidate Lepidoptera-specific genes.     

Case of adult genotype C HBV carrier after acute hepatitis B, losing HBsAg and acquiring HBsAb after IFN and lamivudine treatment.

Here we report the case of a 48-year-old man, carrier of genotype C HBV for longer than 6 months after contracting sexually transmitted acute hepatitis B, who eventually lost HBsAg and acquired HBsAb by IFN/lamivudine therapy. The patient had been negative for HBsAg in 2001, but, during his stay in China from January to July in 2003, he developed acute hepatitis B after having an extra-marital sexual contact there. HBsAg was still positive and a liver biopsy indicated chronic hepatitis when he was admitted to our hospital in December 2003 for detailed examination of liver dysfunction. HBV DNA in his serum, revealed to segregate to genotype C by sequencing on admission, decreased to undetectable levels at the end of a 3-month IFN therapy, and remained undetectable during and after the successive 6-month lamivudine therapy. HBeAg seroconverted to HBeAb during the therapy, and HBsAb appeared after the therapy. To our knowledge, this is the first case of genotype C chronic hepatitis B occurring after acute hepatitis.     

Expression of cyclin-dependent kinase inhibitors in epiphyseal chondrocytes induced to terminally differentiate with thyroid hormone

A growing body of evidence suggests that systemic hormones and peptide growth factors may exert their effects on cell growth and differentiation in part through regulation of the cell division cycle. We hypothesized that thyroid hormone regulates terminal differentiation of growth plate chondrocytes in part through controlling cell cycle progression at the G1/S restriction point. Our results support this hypothesis by demonstrating that treatment of epiphyseal chondrocytes with thyroid hormone under chemically defined conditions results in the arrest of DNA synthesis and the onset of terminal differentiation, indicating that thyroid hormone is one factor capable of regulating the transition between cell growth and differentiation in these cells. This terminal differentiation process is associated with induction of the cyclin/cyclin-dependent kinase inhibitors p21(cip-1 waf-1) and p27kip1, suggesting that thyroid hormone may regulate terminal differentiation in part by arresting cell cycle progression through induction of cyclin-dependent kinase inhibitors.     

Small hepatocellular carcinoma presenting with massive metastasis in the peritoneum, mimicking sarcomatous tumor

The case of a 51-year-old man with hepatitis C virus (HCV)-related hepatocellular carcinoma metastasizing to the peritoneal cavity and mimicking a sarcomatous tumor is presented. A 12 x 12 cm mass, disclosed by computed tomography (CT), in the peritoneal cavity was predominantly isodense to muscle but had hypodense areas that suggested necrosis. T1-weighted magnetic resonance imaging (MRI) showed a large mass, slightly hyperintense to muscle, with local hyperintense areas of suspected hemorrhagic necrosis.T2-weighted MRI of the same region revealed a markedly non-homogeneous and hyperintense mass with inner high signals and peripheral brush-like linear striations. From such imaging studies, sarcomatous tumors, such as fibrosarcoma, leiomyosarcoma, and gastrointestinal stromal tumors, can be distinguished. Pathological findings at autopsy revealed necrotic tissue with a small portion of moderately differentiated HCC. Further studies may provide insights into the metastatic modes of HCC.