Previous studies demonstrated that, compared with long-chain TAG (LCT), dietary medium-chain TAG (MCT) could improve glucose tolerance in rats and humans. It has been well established that adiponectin acts to increase insulin sensitivity. The effects of dietary MCT on adiponectin serum concentration and mRNA levels in adipose tissue were studied in rats. Male Sprague-Dawley rats were fed a diet containing 20% MCT or LCT for 8 wk. After 6 wk of dietary treatment, an oral glucose tolerance test was performed. Rats fed the MCT diet had less body fat accumulation than those fed the LCT diet (P < 0.01). The cell diameter of the perirenal adipose tissue, one of the abdominal adipose tissues, was smaller (P < 0.01) in the MCT diet group. The serum adiponectin concentration was higher (P < 0.01) in the MCT diet group than in the LCT diet group. The adiponectin content in the perirenal adipose tissue was higher (P < 0.01) in the MCT diet group. The MCT-fed group had a higher adiponectin mRNA level in their perirenal adipose tissue (P < 0.05). The increase of the plasma glucose concentration after glucose administration (area under the curve) was smaller (P < 0.01) in the MCT diet group than in the LCT diet group. These findings suggest that dietary MCT, compared with LCT, results in a higher serum adiponectin level with transcriptional activation of the adiponectin gene in rats. We speculate that improved glucose tolerance in rats fed an MCT diet may be, at least in part, ascribed to this higher serum adiponectin level.

We investigated the antihypertensive effect and safety of a-linolenic acid (ALA) in human subjects. In Experiment 1, subjects with high-normal blood pressure and mild hypertension ingested bread containing 14 g of common blended oil (control oil) or ALA-enriched oil for 12 weeks. The test oil contained 2.6g/14 g of ALA. The subjects ingested strictly controlled meals during the study period. Systolic blood pressure was significantly lower in the ALA group than in the control group after ingestion of the test diet for 4, 8 and 12 weeks. Diastolic blood pressure was significantly lower in the ALA group than in the control group after ingestion of the test diet for 12 weeks. In Experiment 2, we evaluated the safety of high intake of ALA (7.8g/d), particularly its effects on oxidation in the body and blood coagulation. Normotensive, high-normotensive and mildly hypertensive subjects ate bread that contained 42 g of the control oil or the test oil for 4 weeks. No significant difference was noted in the lipid peroxide level, high-sensitive C-reactive protein level, plasma prothrombin time or activated partial thromboplastin time between the two groups. No abnormal changes were noted after test diet ingestion on blood test or urinalysis, and no adverse event considered to have been induced by the test oil was observed in Experiment 1 and 2. These results suggest that ALA have an antihypertensive effect with no adverse effect in subjects with high-normal blood pressure and mild hypertension.

Small, round-structured virus (SRSV) was detected in a stool specimen of a patient during an acute gastroenteritis outbreak in Tokyo and was tentatively named SRSV-9. SRSV-9 was purified by sucrose velocity gradient centrifugation after CsCI density gradient centrifugation. The buoyant density of SRSV-9 appeared to be 1.36 g/ml in CsCI. A Western blot (immunoblot) assay using the biotin-avidin system revealed that SRSV-9 was antigenically related to the Hawaii agent but distinct from the Norwalk agent and contained a single major structural protein with a molecular size of 63.0 + 0.6 kilodaltons. The prevalence of SRSV-9 infection in Tokyo was surveyed by the Western blot antibody assay by using a crude virus preparation as the antigen. Seroconversion was observed in 56.5% of the patients involved in the outbreaks from which SRSV was detected by electron microscopy.

Small, round-structured viruses (SRSVs) detected from nonbacterial gastroenteritis outbreaks in Tokyo and Saitama Prefecture, Japan, during the period from 1977 to 1988 were tentatively classified into nine antigenic patterns from SRSV-1 (S-1) to SRSV-9 (S-9) by cross-immune electron microscopy (IEM). S-1 and S-2 appeared pattern specific, while S-3 to S-9, distinguishable from each other in their reactivity, appeared somewhat antigenically related. Their antigenic relatedness to the Norwalk, Hawaii, and Otofuke agents was also examined by IEM by using antisera to these agents. S-3 appeared most closely related to the Norwalk agent. S-4 and S-5 were related to the Norwalk agent and, presumably, were distantly related to the Hawaii and Otofuke agents. S-6 and S-7 were related to the Hawaii and Otofuke agents. S-8 and S-9 were related to the Otofuke agent and, presumably, were distantly related to the Hawaii agent. The prevalence of each antigenic pattern in 38 outbreaks was examined: S-8 was implicated in 24% of the outbreaks, S-5 in 16%, S-4 in 13%, S-9 in 13%, S-6 in 11%, and others in 5%.

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