A unique mitovirus from Glomeromycota,the phylum of arbuscular mycorrhizal fungi

Arbuscular mycorrhizal (AM) fungi that belong to the phylum Glomeromycota associate with most land plants and supply mineral nutrients to the host plants. One of the four viral segments found by deep-sequencing of dsRNA in the AM fungus Rhizophagus clarus strain RF1 showed similarity to mitoviruses and is characterized in this report. The genome segment is 2,895 nucleotides in length, and the largest ORF was predicted by applying either the mold mitochondrial or the universal genetic code. The ORF encodes a polypeptide of 820 amino acids with a molecular mass of 91.2 kDa and conserves the domain of the mitovirus RdRp superfamily. Accordingly, the dsRNA was designated as R. clarus mitovirus 1 strain RF1 (RcMV1-RF1). Mitoviruses are localized exclusively in mitochondria and thus generally employ the mold mitochondrial genetic code. The distinct codon usage of RcMV1-RF1, however, suggests that the virus is potentially able to replicate not only in mitochondria but also in the cytoplasm. RcMV1-RF1 RdRp showed the highest similarity to the putative RdRp of a mitovirus-like ssRNA found in another AM fungus, followed by RdRp of a mitovirus in an ascomycotan ectomycorrhizal fungus. The three mitoviruses found in the three mycorrhizal fungi formed a deeply branching clade that is distinct from the two major clades in the genus Mitovirus.     

Mutation analysis of a Japanese patient with fucosidosis

Fucosidosis is a rare autosomal recessive disorder resulting from a deficiency of α-L-fucosidase. Recently, various mutations have been reported in this disease, but it is difficult to elucidate the phenotype from the genetic mutations. We report a patient with chronic infantile type fucosidosis, with a compound heterozygote of a nonsense mutation (W148X, Trp at codon 148 to stop codon) and a large deletion, including all exons. This is the first report of a large deletion demonstrated in fucosidosis. It is interesting that this patient has a relatively mild clinical course despite the absence of the mRNA. This case also indicates the difficulty in determining the phenotype from the genotype in fucosidosis. Received: February 19, 1999 / Accepted: April 16, 1999     

Clinicopathological features of gastric carcinoma in younger and middle-aged patients: A comparative study

Gastric carcinoma is relatively rare in patients under the age of 40. This study was undertaken to clarify the clinicopathological characteristics and surgical outcomes of gastric carcinoma in younger patients compared with those of middle-aged patients. The surgical results from 131 younger patients (aged ⩽40 years) and 918 middle-aged patients (aged 55–65 years) were compared retrospectively. Female gender, undifferentiated tumor type and lymphatic invasion were significantly more common in the younger patients. Survival time did not differ between the two groups. The depth of tumor invasion was the only prognostic factor in younger patients, whereas macroscopic appearance, tumor diameter, depth of invasion, lymph node metastasis, and venous invasion were all significant prognostic factors in middle-aged patients. Peritoneal recurrence was significantly more common in younger patients. A family history of gastric adenocarcinoma was observed in 25.9% of younger patients, but this did not affect survival outcomes. As depth of invasion affects prognosis independently, and peritoneal metastasis is the predominant pattern of recurrence, it is essential to establish an optimal prophylactic treatment for peritoneal metastasis to improve surgical outcomes in younger patients with advanced gastric cancer.     

Priority of Lymph Node Dissection for Siewert Type II/III Adenocarcinoma of the Esophagogastric Junction

Objective

The purpose of this study was to clarify the priority of nodal dissection in Siewert types II and III adenocarcinoma of the esophagogastric junction (AEG).

Methods

The priority of nodal dissection was evaluated based on the therapeutic value index calculated by multiplying of the frequency of metastasis to each station and the 5-year survival rate of patients with metastasis to that station.

Results

A total of 176 patients (95 type II and 81 type III) were examined. Among the lymph nodes that had a metastatic incidence exceeding 10 %, the stations showing the first to fourth highest index were the paracardial and lesser curvature nodes (Nos. 1, 2, and 3) and the node at the root of the left gastric artery (No. 7) in the total cohort, as well as in each type. The next station was the lower thoracic paraesophageal lymph node (No. 110), followed by the nodes along the proximal splenic artery (No. 11p) in type II, whereas it was the nodes along the proximal splenic artery (No. 11p) followed by the para-aortic nodes (No. 16a2), the nodes at the celiac artery (No. 9), and the nodes around the splenic hilum (No. 10) in type III.

Conclusions

These results suggest that the highest priority nodal stations to be dissected were the paracardial and lesser curvature nodes (Nos. 1, 2, and 3) and the nodes at the root of the left gastric artery (No. 7), regardless of the Siewert subtype, but the subsequent priority was different depending on the subtype.     

Leukocyte angiotensin II levels inpatients with essential hypertension:relation to insulin resistance

Insulin resistance is involved in the pathogenesis of type 2 diabetes, hypertension, and atherosclerosis. Angiotensin (Ang) converting enzyme inhibitors and Ang II type 1 receptor antagonists improve insulin resistance in patients with essential hypertension, which suggest that tissue Ang II is involved in insulin resistance in patients with hypertension. To investigate the participation of tissue Ang II in insulin resistance associated with hypertension, we evaluated the Ang II-generating system in leukocytes and its relation to insulin resistance in patients with essential hypertension. Eighteen patients with essential hypertension participated in this study. Ang II was separated from leukocytes by reversed-phase high-performance liquid chromatography and measured by radioimmunoassay. Insulin resistance was evaluated by determining the steady-state of plasma glucose (SSPG) concentration. The Ang I- and Ang II-generating activities were evaluated in human leukocytes. Human leukocytes have Ang I- and Ang II-generating activities. The Ang II-generating activity was significantly inhibited by pepstatin A. Leukocyte Ang II level does not correlate with BP or plasma Ang II level in patients with essential hypertension. Leukocyte Ang II level strongly correlates with SSPG concentration, and significantly correlates with body mass index and plasma insulin, and with leptin levels in patients with essential hypertension. Leukocyte Ang II may be directly associated with insulin resistance.     

The biphasic effect of extracellular glucose concentration on carbachol‐induced fluid secretion from mouse submandibular glands

Cholinergic agonists evoke elevations of the cytoplasmic free‐calcium concentration ([Ca²⁺]_i) to stimulate fluid secretion in salivary glands. Salivary flow rates are significantly reduced in diabetic patients. However, it remains elusive how salivary secretion is impaired in diabetes. Here, we used an ex vivo submandibular gland perfusion technique to characterize the dependency of salivary flow rates on extracellular glucose concentration and activities of glucose transporters expressed in the glands. The cholinergic agonist carbachol (CCh) induced sustained fluid secretion, the rates of which were modulated by the extracellular glucose concentration in a biphasic manner. Both lowering the extracellular glucose concentration to less than 2.5 mM and elevating it to higher than 5 mM resulted in decreased CCh‐induced fluid secretion. The CCh‐induced salivary flow was suppressed by phlorizin, an inhibitor of the sodium–glucose cotransporter 1 (SGLT1) located basolaterally in submandibular acinar cells, which is altered at the protein expression level in diabetic animal models. Our data suggest that SGLT1‐mediated glucose uptake in acinar cells is required to maintain the fluid secretion by sustaining Cl^? secretion in real‐time. High extracellular glucose levels may suppress the CCh‐induced secretion of salivary fluid by altering the activities of ion channels and transporters downstream of [Ca²⁺]_i signals.