Severe Hemolysis after Distal Splenorenal Shunt

We report a case of severe hemolysis after distal splenorenal shunt. Hemolysis was suddenly recognized at the time splenorenal venous anastomosis was completed, and it continued on the operative day and the first postoperative day. After the shunt, the intraoperative splenic venous blood flow was approximately double its previous level, as measured by electromagnetic flowmeter. Angiographic partial splenic embolization was performed on the second postoperative day, and then hemolysis stopped suddenly. This suggested that hemolysis after distal splenorenal shunt was related to increased splenic blood flow and acceleration of erythrocyte destruction.     

Abnormal tumor vasculatures and bone marrow-derived pro-angiogenic cells in cancer

Tumor-derived factors affect the stroma of cancer tissue by activating pro-angiogenic signals. One of the key components of this response is the mobilization of the pro-angiogenic cells from bone marrow (BM), which contribute to the development of abnormal tumor vasculature. Evidence is accumulating that the pro-angiogenic cells derived from BM are involved in the physiological processes of tissue repair and wound healing. However, vascular structure in cancer tissue is impaired, resulting in the formation of chaotic neo-vessels and hypoxic microenvironments. Ultimately, these structural and functional abnormalities result in the limited delivery of chemotherapeutic agents and create regions of metabolic derangement, both of which enhance resistance to chemotherapy. In spite of recent advances in targeted therapy using anti-vascular agents, clinical results from studies using individual agents have unsatisfactory, necessitating the combinatorial use of anti-cancer drugs and a targeting agent. We suggest the possibility of a new therapeutic approach in which aberrant tumor vessels are normalized by BM-derived pro-angiogenic cells, and the delivery of anti-cancer drugs is maximized. In this review, we focus on the current understanding of the structure and function of tumor vessels, and an alternative approach to the repair of abnormal tumor vasculature by the use of BM-derived pro-angiogenic cells. This approach may improve both the delivery and the efficacy of anti-cancer drugs by restoring aberrant tumor vascularization and hypoxia.     

Comparison of PPIs and H2-receptor antagonists plus prokinetics for dysmotility-like dyspepsia

AIM: To compare efficacy of proton pump inhibitors (PPIs) with H₂-receptor antagonists (H₂RAs) plus prokinetics (Proks) for dysmotility-like symptoms in functional dyspepsia (FD).METHODS: Subjects were randomized to receive open-label treatment with either rabeprazole 10 mg od (n = 57) or famotidine 10 mg bid plus mosapride 5 mg tid (n = 57) for 4 wk. The primary efficacy endpoint was change (%) from baseline in total dysmotility-like dyspepsia symptom score. The secondary efficacy endpoint was patient satisfaction with treatment.RESULTS: The improvement in dysmotility-like dyspepsia symptom score on day 28 was significantly greater in the rabeprazole group (22.5% ± 29.2% of baseline) than the famotidine + mosapride group (53.2% ± 58.6% of baseline, P < 0.0001). The superior benefit of rabeprazole treatment after 28 d was consistent regardless of Helicobacter pylori status. Significantly more subjects in the rabeprazole group were satisfied or very satisfied with treatment on day 28 than in the famotidine + mosapride group (87.7% vs 59.6%, P = 0.0012). Rabeprazole therapy was the only significant predictor of treatment response (P < 0.0001), defined as a total symptom score improvement ≥ 50%.CONCLUSION: PPI monotherapy improves dysmotility-like symptoms significantly better than H₂RAs plus Proks, and should be the treatment of first choice for Japanese FD.     

Spinal cord injury following aortic arch replacement

Surgery Today - Postoperative spinal cord injury is a devastating complication after aortic arch replacement. The purpose of this study was to determine the predictors of this complication. A group...     

Diagnostic criteria for atypical hemolytic uremic syndrome proposed by the joint committee of the Japanese society of nephrology and the Japan pediatric society

Atypical hemolytic uremic syndrome (aHUS) is rare and comprises the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. Recently, abnormalities in the mechanisms underlying complement regulation have been focused upon as causes of aHUS. The prognosis for patients who present with aHUS is very poor, with the first aHUS attack being associated with a mortality rate of ~25 %, and with ~50 % of cases resulting in end-stage renal disease requiring dialysis. If treatment is delayed, there is a high risk of this syndrome progressing to renal failure. Therefore, we have developed diagnostic criteria for aHUS to enable its early diagnosis and to facilitate the timely initiation of appropriate treatment. We hope these diagnostic criteria will be disseminated to as many clinicians as possible and that they will be used widely.     

Transferrin is not involved in initial uptake process of iron in rat duodenal mucosa

The role of transferrin in iron absorption by the duodenal mucosa in rats with iron deficiency and controls was evaluated immunohistochemically. Ferric iron was administered to each rat using a metallic gastric tube. Transferrin was stained by an immunoperoxidase method and iron with Prussian blue in the same duodenal sections and observed by light microscopy. The localization of transferrin differed from that of ferric iron both in rats with iron deficiency and in controls. In iron-deficient rats, transferrin was weakly stained after iron administration but was strongly stained after saline administration. In contrast, in controls, transferrin was weakly stained after saline administration but was strongly stained after iron administration. By electron microscopy, x-ray energy spectrometric analysis of the transferrin-positive areas showed no iron peak. In iron-deficient rats, accumulation of electron-dense transferrinnegative microgranules was observed in some of the duodenal columnar epithelium. X-ray energy spectrometric analysis of this area revealed iron, indicating iron absorption. These results suggest that mucosal transferrin does not act as a shuttle protein in iron absorption via the rat duodenal columnar epithelium, and the function of this protein may be to inform the absorptive cells of the iron status of the body as observed in other organs.     

The latest wire technique for chronic total occlusion.

If patency is restored after chronic total occlusion (CTO), it can be maintained over the long term by implanting drug-eluting stents. The cause of unsuccessful percutaneous coronary intervention is usually failure of the wire to cross the site of CTO. The objective of this article is to describe the latest wire techniques for CTO. As for wire selection, CTO should generally be treated with hard-tipped spring wires, preferably Conquest Pro series (Asahi Intec). According to the penetrating strategy, the course of a blood vessel with CTO is established preoperatively and the wire is advanced based on the imaging data with minimum rotation (a torque of +/- 90 degrees or less). If the operator encounters divergence between the preoperative CTO image and the actual course of the coronary artery, the parallel wire technique should be used. With this method, a wire which enters the subintimal space is left there, and a second wire is inserted along it to find a new channel. When this technique is successful, the following findings are often noted: 1) the second wire crosses over the first one in the CTO; 2) the second wire shows more acute curve than the first wire; 3) the second wire penetrates the lesion from the outer curvature of the coronary artery and then is advanced along the same curvature of the vessel. Indeed, the second wire should be operated intentionally to achieve these findings so that the probability of success increases and the duration of the procedure is shortened.     

Localization of hepatitis A virus in marmoset liver tissue during the acute phase of experimental infection

Electron microscopic and virological studies of marmoset liver tissue with acute infection of hepatitis A virus (HAV), especially in the earlier stages of infection, were carried out to characterize the maturation process of HAV. Four marmosets were inoculated intravenously with HAV suspension and sacrificed 1 week, 2 weeks, 3 weeks and 4 weeks after inoculation respectively. Hepatitis A antigen (HAAg) in 10% liver homogenates of marmosets was examined by radioimmunoassay and a large amount of HAAg was detected in the liver homogenate of two marmosets sacrificed 2 weeks and 3 weeks after inoculation respectively. The histodiagnosis of the marmoset sacrificed 2 weeks after HAV inoculation was normal. However, many clusters of virus-like particles about 27 nm in diameter, in both "solid" and "empty" forms were found, mainly in vesicles of Kupffer cells by electron microscopy. In the animal that developed mild hepatitis 3 weeks after inoculation HAV-like particles were found in vesicles of hepatocytes by electron microscopy. By immune electron microscopy using peroxidase-conjugated anti-hepatitis A antibody, HAAg was detected on the particles present within the cytoplasmic vesicles of Kupffer cells or hepatocytes and on the surrounding membrane of the vesicles which contained HAV-like particles.     

Structural and biochemical basis for the inhibition of cell death by APIP,a methionine salvage enzyme

APIP, Apaf-1 interacting protein, has been known to inhibit two main types of programmed cell death, apoptosis and pyroptosis, and was recently found to be associated with cancers and inflammatory diseases. Distinct from its inhibitory role in cell death, APIP was also shown to act as a 5-methylthioribulose-1-phosphate dehydratase, or MtnB, in the methionine salvage pathway. Here we report the structural and enzymatic characterization of human APIP as an MtnB enzyme with a K_m of 9.32 μM and a V_max of 1.39 μmol min⁻¹ mg⁻¹. The crystal structure was determined at 2.0-Å resolution, revealing an overall fold similar to members of the zinc-dependent class II aldolase family. APIP/MtnB exists as a tetramer in solution and exhibits an assembly with C4 symmetry in the crystal lattice. The pocket-shaped active site is located at the end of a long cleft between two adjacent subunits. We propose an enzymatic reaction mechanism involving Glu139* as a catalytic acid/base, as supported by enzymatic assay, substrate-docking study, and sequence conservation analysis. We explored the relationship between two distinct functions of APIP/MtnB, cell death inhibition, and methionine salvage, by measuring the ability of enzymatic mutants to inhibit cell death, and determined that APIP/MtnB functions as a cell death inhibitor independently of its MtnB enzyme activity for apoptosis induced by either hypoxia or etoposide, but dependently for caspase-1-induced pyroptosis. Our results establish the structural and biochemical groundwork for future mechanistic studies of the role of APIP/MtnB in modulating cell death and inflammation and in the development of related diseases.The programmed death of dangerous cells, either infected or transformed, has critical importance for the survival of the multicellular organism and therefore is also of great medical relevance. APIP, Apaf-1 interacting protein, was initially identified as an inhibitor of apoptotic cell death induced by hypoxia/ischemia and cytotoxic drugs (1). Recently APIP was also shown to inhibit pyroptosis, an inflammatory form of cell death, induced by Salmonella infection (2). Thus, APIP has been implicated in two major types of programmed cell death: apoptosis and pyroptosis. In apoptosis, APIP inhibits the mitochondrial pathway involving caspase-9 but not the receptor pathway involving caspase-8 (1, 3). In pyroptosis, APIP’s inhibitory function was recently revealed in a functional genetic screen for the SNP associated with increased caspase-1–mediated cell death in response to Salmonella infection (2) and subsequently confirmed by cell viability assays (2, 4). Intriguingly, other SNPs near APIP were found in patients suffering from systemic inflammatory response syndrome (2), which further implicates APIP in inflammation.Distinct from its inhibitory role in the programmed cell death, APIP was recently shown to act as an enzyme in the methionine salvage pathway (2, 4). The amino acid sequence of human APIP exhibits 23–26% identity to the previously characterized Bacillus and yeast 5-methylthioribulose-1-phosphate dehydratase (MtnB) (4). The methionine salvage pathway converts MTA (5-methylthioadenosine) to methionine through six enzymatic reaction steps, and MtnB is the third enzyme in the pathway and catalyzes the dehydration of MTRu-1-P (5-methylthioribulose-1-phosphate) to DK-MTP-1-P (2,3-diketo-5-methylthiopentyl-1-phosphate) (Fig. 1B) (4, 5). In the absence of methionine, cells supplemented with MTA exhibit decreased viability when APIP expression is reduced (2, 4). These studies indicate that APIP is an MtnB enzyme in the methionine salvage pathway.Open in a separate windowFig. 1.APIP as an MtnB enzyme in the methionine salvage pathway. (A) Initial reaction rate was plotted at seven different concentrations of the substrate MTRu-1-P for Michaelis-Menten kinetic analysis. Data represent mean values with SE from three independent measurements. (B) Methionine salvage pathway characterized in Homo sapiens and Saccharomyces cerevisiae converts MTA to methionine (Met) through the common six enzymatic reactions. Dashed line represents B. subtilis methionine salvage reaction steps distinct from H. sapiens and S. cerevisiae. Gray colored enzymatic steps and metabolites represent biochemical links that are not conceptually part of the methionine salvage pathway. AdoMet, S-adenosyl-l-methionine; dAdoMet, decarboxylated AdoMet; DHK-MTPene, 1,2-dihydroxy-3-keto-5-methylthiopentene; HK-MTPenyl-1-P, 2-hydroxy-3-keto-5-methylthiopentenyl-1-phosphate; Met, l-methionine; MTOB, 4-methylthio-2-oxobutyrate; MTR, 5-methylthioribose.The methionine salvage pathway is found in all organisms, from bacteria to plants and animals (6). The role of this pathway is to recycle MTA, which is a by-product of the polyamine synthetic process, back to methionine (Fig. 1B). The methionine salvage pathway is beneficial as a means of recycling the sulfur present in MTA because assimilation of sulfur is thermodynamically costly (6). The metabolic importance of the pathway is underscored in humans because methionine is one of the essential amino acids needed to be provided through the diet, in which it is one of the most limiting amino acids (6). Recently, the methionine salvage pathway attracted medical interest because it was implicated in cell death and inflammation and diseases associated with these processes. For example, metabolites such as MTA and 2-keto-4-methylthiobutyrate (KMTB) have effects of apoptosis induction (6–9). MTA was also shown to induce caspase-1–dependent pyroptosis in the inflammatory response to bacterial infection (2). In addition, the 5-methylthioadenosine phosphorylase (MTAP, which catalyzes the first step) is a tumor suppressor implicated in a various human cancers (6, 10), and aci-reducton dioxygenase 1 (ADI1, also called MtnD, which catalyzes the fifth step) has a similar role in prostate cancer (11, 12). Human APIP/MtnB, which is the focus of the present study, is another example of a methionine salvage enzyme that is implicated in cell death and inflammation. APIP/MtnB was recently reported to be up-regulated in squamous carcinoma cells from tongue and larynx (13) and down-regulated in the cells and tumors of non–small-cell lung carcinoma (14). In addition, APIP/MtnB is implicated in inflammatory conditions that likely involve caspase-1–dependent pyroptosis, such as systemic inflammatory response syndrome (2).Studies of APIP/MtnB to date have focused mainly on its functional role either in cell death or in methionine salvage. To gain a better understanding of APIP/MtnB at a molecular and biochemical level, we carried out a structural and biochemical characterization in this study. The MtnB enzyme activity of APIP was verified by an in vitro enzyme assay. In addition, the crystal structure was determined at 2.0-Å resolution, which revealed details of the active site architecture and led to a proposed catalytic mechanism. Furthermore, we explored the relationship between two distinct functions of APIP/MtnB, cell death inhibition, and methionine salvage, by testing its enzymatic mutants derived from the crystal structure for their ability to inhibit two main types of programmed cell death: pyroptosis and apoptosis.     

Soy β-conglycinin improves glucose uptake in skeletal muscle and ameliorates hepatic insulin resistance in Goto-Kakizaki rats

Although the underlying mechanism is unclear, β-conglycinin (βCG), the major component of soy proteins, regulates blood glucose levels. Here, we hypothesized that consumption of βCG would normalize blood glucose levels by ameliorating insulin resistance and stimulating glucose uptake in skeletal muscles. To test our hypothesis, we investigated the antidiabetic action of βCG in spontaneously diabetic Goto-Kakizaki (GK) rats. Our results revealed that plasma adiponectin levels and adiponectin receptor 1 messenger RNA expression in skeletal muscle were higher in βCG-fed rats than in casein-fed rats. Phosphorylation of adenosine monophosphate–activated protein kinase (AMP kinase) but not phosphatidylinositol-3 kinase was activated in βCG-fed GK rats. Subsequently, βCG increased translocation of glucose transporter 4 to the plasma membrane. Unlike the results in skeletal muscle, the increase in adiponectin receptor 1 did not lead to AMP kinase activation in the liver of βCG-fed rats. The down-regulation of sterol regulatory element-binding factor 1, which is induced by low insulin levels, promoted the increase in hepatic insulin receptor substrate 2 expression. Based on these findings, we concluded that consumption of soy βCG improves glucose uptake in skeletal muscle via AMP kinase activation and ameliorates hepatic insulin resistance and that these actions may help normalize blood glucose levels in GK rats.