The carboxyl-terminal tail of the stalk of Arabidopsis NACK1/HINKEL kinesin is required for its localization to the cell plate formation site.

Plant cytokinesis is achieved by formation of cell plates in the phragmoplast, a plant-specific cytokinetic apparatus, which consists of microtubules (MTs) and microfilaments. During cytokinesis, the cell plate is expanded centrifugally outward from the inside of cells in a process that is supported by dynamic turnover of MTs. M-phase-specific kinesin NACK1, which comprises the motor domain at the amino-terminal half to move on MT bundles and the stalk region in the carboxyl-terminal half, is a key player in the process of MT turnover. That is, the specific region in the stalk binds the MAP kinase kinase kinase to activate the whole MAP kinase cascade, which stimulates depolymerization of MTs for the MT turnover. The stalk is also responsible for recruiting the activated kinase cascade to the mid-zone of the phragmoplast, which corresponds to the cell-plate formation site. It should be crucial to uncover roles of the NACK1 kinesin stalk as well as the motor domain in the formation of cell plates in order to understand the mechanisms of cell plate formation. Using dissected Arabidopsis NACK1 (AtNACK1/HINKEL) molecules and AtNACK1-fused GFP, we showed that the C-terminal tail of the stalk in addition to the motor domain is critical for its proper localization to the site of cell plate formation in the phragmoplast, probably by affecting its motility activity.

Long term results of balloon-occluded retrograde transvenous obliteration for portosystemic shunt encephalopathy in patients with liver cirrhosis and portal hypertension.

This study examined 19 patients with portosystemic shunt encephalopathy caused by a splenorenal shunt (SRS), which was treated with balloon-occluded retrograde transvenous obliteration (B-RTO). Long-term treatment outcomes were evaluated based on hepatic functional reserve and vital prognosis. Encephalopathy improved in all patients after shunt embolization and closure. Albumin, serum ammonia, and the Child-Pugh score, a measure of liver function, were significantly improved 3 years after B-RTO, and exacerbation of damage to liver function was avoided (p<0.01). During the follow-up period, three patients died from liver failure and two patients from hepatocellular carcinoma. Patients had a poor prognosis if their albumin levels were less than 2.8 mg / dL before B-RTO (p<0.05). Encephalopathy patients had complete response to B-RTO, but long-term prognosis was affected by hepatic functional reserve before B-RTO and by concurrent hepatocellular carcinoma. The results of this study suggest that in patients with SRS, it is important to perform B-RTO at an early stage when the hepatic functional reserve is still satisfactory.

Balloon-occluded retrograde transvenous obliteration versus endoscopic injection sclerotherapy for isolated gastric varices: a comparative study.

Isolated gastric varices (IGV) have a lower risk of bleeding than esophageal varices, however IGV bleeding is associated with a higher mortality than bleeding of esophageal varices. In recent years, two widely used treatments for IGV have been balloon-occluded retrograde transvenous obliteration (B-RTO) and endoscopic injection sclerotherapy (EIS) using cyanoacrylate or ethanolamine oleate (EO). This study compared these two treatment methods for IGV. The subjects were 112 patients who were treated at our hospital for IGV bleeding between October 1990 and December 2003. Forty-nine (49) patients were treated with B-RTO and 63 patients with EIS. These two patient groups were compared as regards content of treatment, post-treatment incidence of variceal bleeding, incidence of IGV rebleeding, survival rate, cause of death, and complications. Multivariate analysis was performed on post-treatment variceal bleeding and survival. Although EO was used in higher amounts in the B-RTO group than in the EIS group, the B-RTO group had a significantly lower number of treatment sessions and a significantly shorter treatment period (p<0.05). The EIS group had significantly more patients with IGV rebleeding after treatment than the B-RTO group. Treatment method was the only independent prognostic factor of IGV bleeding after treatment (p=0.024). The two groups did not differ significantly in the percentage of patients with aggravated esophageal varices after treatment. Bleeding from ectopic varices was not observed in any patient. There was no significant difference in survival by treatment method. The presence of hepatocellular carcinoma was the only independent prognostic factor for survival (p=0.003). It is concluded that B-RTO was more effective than EIS in the eradication of IGV and prevention of IGV recurrence and rebleeding.

Effect of Helicobacter pylori infection on esophagogastric variceal bleeding in patients with liver cirrhosis and portal hypertension.

BACKGROUND AND AIMS: Bleeding from esophageal and gastric varices is a fatal event in patients with liver cirrhosis and portal hypertension. However, the effects of Helicobacter pylori (H. pylori) infection on esophagogastric variceal bleeding are not known. The present study was aimed to elucidate the role of H. pylori infection in esophagogastric variceal bleeding. METHODS: The subjects were 196 cirrhotic patients who were admitted to the Kurume University Hospital to treat their esophagogastric varices consisted of 95 with acute bleeding and 101 with nonbleeding but high risk of bleeding. For the diagnosis of H. pylori infection, a (13) C-urea breath test was used, and serum pepsinogen (PG) I and II levels and the PG I/II ratio were also measured. RESULTS: Esophagogastric variceal bleeding was seen in 34.9% (n = 30) of the H. pylori-infected patients (n = 86) and in 59.1% (n = 65) of the noninfected patients (n = 110) (P < 0.0007). There was no significant difference in the infection rate between the bleeding sites of the esophagus and the stomach. The serum PG I and II levels and the PG I/II ratio were 65.6 ng/dL, 14.7 ng/dL, and 4.4, respectively, for the bleeding patients (n = 95), and 43.7 ng/dL, 17.7 ng/dL, and 3.1 for the nonbleeding patients (n = 101). Thus, the nonbleeding patients had significantly higher rate of H. pylori infection and lower acid secretion than bleeding patients (0.001). In addition, multivariate logistic regression analysis showed a significant negative association between H. pylori infection and esophagogastric variceal bleeding. CONCLUSIONS: These results suggest that H. pylori infection has a protective effect against esophagogastric variceal bleeding through the induction of gastric mucosal atrophy and concomitant hypoacidity.