[Effects of Medium Chain Triglycerides Intake on Lipid Metabolism and Intestinal Disaccharidase Activities in Rats].

It has been reported that medium-chain triglyceride (MCT) have various physiological functions, such as anti-obesity and hypolipidemic effects. They can also elicit increased disaccharidase activity and intestinal cell proliferation. However, a meta-analysis of randomized controlled trials, comparing the effects of MCT on weight loss and body composition, detected commercial bias. Additional research on the physiological functions is needed in order to have conclusive evidence. Thus, we sought to evaluate the various functions of MCT by conducting a feeding study in rats. Rats fed a diet containing 15% (w/w) MCT, had significantly lower visceral fat weight, plasma and liver lipid concentrations; they had significantly higher intestinal maltase and glucoamylase activities; and they had a greater number of Ki-67 positive cells/crypt, compared to the rats fed a diet containing 15% (w/w) lard. The effects of a diet containing 5% (w/w) MCT was observed only for plasma cholesterol levels and the number of Ki-67 positive cells/crypt; in which some results were found to be inconsistent with previous reports. These results indicate that physiological functions of MCT are numerous and need to be confirmed by additional research.

Chained nuclei and python pattern in skeletal muscle cells as histological markers for electrical injury.

Electrical injury is damage caused by an electrical current passing through the body. We have previously reported that irregular stripes crossing skeletal muscle fibers (python pattern) and multiple small nuclei arranged in the longitudinal direction of the muscle fibers (chained nuclear change) are uniquely observed by histopathological analysis in the skeletal muscle tissues of patients with electrical injury. However, it remains unclear whether these phenomena are caused by the electrical current itself or by the joule heat generated by the electric current passing through the body. To clarify the causes underlying these changes, we applied electric and heat injury to the exteriorized rat soleus muscle in situ. Although both the python pattern and chained nuclear change were induced by electric injury, only the python pattern was induced by heat injury. Furthermore, a chained nuclear change was induced in the soleus muscle cells by electric current flow in physiological saline at 40 °C ex vivo, but a python pattern was not observed. When the skeletal muscle was exposed to electrical injury in cardiac-arrested rats, a python pattern was induced within 5 h after cardiac arrest, but no chained nuclear change was observed. Therefore, a chained nuclear change is induced by an electrical current alone in tissues in vital condition, whereas a python pattern is caused by joule heat, which may occur shortly after death. The degree and distribution of these skeletal muscle changes may be useful histological markers for analyzing cases of electrical injury in forensic medicine.

A Case of Sudden Infant Death Due to Incomplete Kawasaki Disease.

Although Kawasaki disease (KD) is a self-limiting disease, it may cause sudden cardiac death. Diagnosis of KD is principally based on clinical signs; however, some infant cases do not meet the criteria. Such cases are identified as incomplete KD. The sudden death risk in incomplete KD cases is similar to conventional KD. In our 5-month-old case, he had been admitted to a hospital for a fever and suppuration at the site of Bacille de Calmette et Guerin (BCG) vaccination. However, after discharge from the hospital, his C-reactive protein (CRP) levels declined, he got indisposed and died suddenly. A medico-legal autopsy revealed myocarditis, coronaritis, platelet-aggregated emboli in coronary arteries, and myocardial degeneration, suggesting that the fatal myocardial infarction was due to thrombus emboli in the coronary arteries. Forensic pathologists therefore should pay attention to the cardiac pathology originated from incomplete KD as a potential cause in cases of sudden infant death.

Brain stem hemorrhage due to cerebral amyloid angiopathy: the autopsy of a patient with Alzheimer's disease at a young age.

We report findings from an autopsy of a male in his 40s who died of a brain stem hemorrhage associated with cerebral amyloid angiopathy (CAA), senile plaques (SPs) and neurofibrillary tangles (NFTs), which are histopathological changes associated with Alzheimer's disease (AD). Our immunohistochemical study demonstrated amyloid ß (Aß) deposition in the small cerebral arteries and SPs. Although hypertension (178/132 mmHg) was detected, the subject was not treated accordingly. CAA coupled with hypertension might have caused the intracerebral hemorrhage (ICH).

Anti-tumor effect of orally administered spinach glycolipid fraction on implanted cancer cells, colon-26, in mice.

We succeeded in purifying a major glycolipid fraction from a green vegetable, spinach. This fraction consists mainly of three glycolipids: monogalactosyl diacylglycerol (MGDG), digalactosyl diacylglycerol (DGDG), and sulfoquinovosyl diacylglycerol (SQDG). In a previous study, we found that the glycolipid fraction inhibited DNA polymerase activity, cancer cell growth and tumor growth with subcutaneous injection. We aimed to clarify oral administration of the glycolipid fraction, suppressing colon adenocarcinoma (colon-26) tumor growth in mice. A tumor graft study showed that oral administration of 20 mg/kg glycolipid fraction for 2 weeks induced a 56.1% decrease in the solid tumor volume (P < 0.05) without any side-effects, such as loss of body weight or major organ failure, in mice. The glycolipid fraction induced the suppression of colon-26 tumor growth with inhibition of angiogenesis and the expression of cell proliferation marker proteins such as Ki-67, proliferating cell nuclear antigen (PCNA), and Cyclin E in the tumor tissue. These results suggest that the orally administered glycolipid fraction from spinach could suppress colon tumor growth in mice by inhibiting the activities of neovascularization and cancer cellular proliferation in tumor tissue.

Anti-tumor effects of the glycolipids fraction from spinach which inhibited DNA polymerase activity.

We succeeded in purifying the fraction of monogalactosyl diacylglycerol (MGDG), digalactosyl diacylglycerol (DGDG), and sulfoquinovosyl diacylglycerol (SQDG) containing the major glycolipids from a green vegetable, spinach (Spinacia oleraceaL.). This glycolipids fraction inhibited the activities of replicative DNA polymerases (pols) such as alpha, delta, and epsilon, and mitochondrial pol gamma with IC50 values of 44.0-46.2 microg/ml, but had no influence on the activity of repair-related pol beta. The fraction also inhibited the proliferation of human cervix carcinoma (HeLa) cells with LD50 values of 57.2 microg/ml. In an in vivo anti-tumor assay on nude mice bearing solid tumors of HeLa cells, the fraction was shown to be a promising suppressor of solid tumors. Histopathological examination revealed that tumor necrosis with hemorrhage was significantly enhanced with the glycolipids fraction in vivo. The spinach glycolipids fraction might be a potent anti-tumor compound, and this fraction may be a healthy food substance with anti-tumor activity.

Anti-tumor effects of dehydroaltenusin, a specific inhibitor of mammalian DNA polymerase alpha.

In the screening of selective inhibitors of eukaryotic DNA polymerases (pols), dehydroaltenusin was found to be an inhibitor of pol alpha from a fungus (Alternaria tennuis). We succeeded in chemically synthesizing dehydroaltenusin, and the compound inhibited only mammalian pol alpha with IC50 value of 0.5 microM, and did not influence the activities of other replicative pols such as pols delta and epsilon, but also showed no effect on pol alpha activity from another vertebrate, fish, or from a plant species. Dehydroaltenusin also had no influence on the other pols and DNA metabolic enzymes tested. The compound also inhibited the proliferation of human cancer cells with LD50 values of 38.0-44.4 microM. In an in vivo anti-tumor assay on nude mice bearing solid tumors of HeLa cells, dehydroaltenusin was shown to be a promising suppressor of solid tumors. Histopathological examination revealed that increased tumor necrosis and decreased mitotic index were apparently detected by the compound in vivo. Therefore, dehydroaltenusin could be of interest as not only a mammalian pol alpha-specific inhibitor, but also as a candidate drug for anti-cancer treatment.

Alpha-sulfoquinovosylmonoacylglycerol is a novel potent radiosensitizer targeting tumor angiogenesis.

Angiogenesis is a promising target for the treatment of cancer, and varying types of antiangiogenic agents have been developed. However, limitations and problems associated with antiangiogenic therapy have recently arisen. Although radiotherapy can be combined with antiangiogenic compounds to overcome these difficulties, almost all previously described angiogenesis inhibitors could still cause side effects at effective doses, and only additive effects are seen in current combination therapy. In this study, we identified a member of the sulfoquinovosylacylglycerols, alpha-sulfoquinovosylmonoacylglycerol (alpha-SQMG), originally derived from sea urchins, as a potent radiosensitizer. The agent synergistically inhibits angiogenesis at low doses when combined with ionizing radiation. Combined treatment with alpha-SQMG and radiation seems to promote the adoption of a senescence-like phenotype by vascular endothelial cells. Finally, the agent remarkably enhances the radioresponse of human tumors transplanted into nude mice, accompanied by a significant reduction in the vascularity of the tumors. Collectively, alpha-SQMG may be a novel potent radiosensitizer targeting angiogenesis.

Intracardiac fibroblasts, but not bone marrow derived cells, are the origin of myofibroblasts in myocardial infarct repair.

UNLABELLED: Origin of myofibroblasts in infarcted myocardium was examined by using rats in which bone marrow of green fluorescent protein (GFP)-transgenic mice had been transplanted. GFP was not detected in myofibroblasts at either 3 or 7 days after infarction, suggesting that proliferating myofibroblasts in infarcted myocardium are derived from resident fibroblasts rather than circulating precursor cells of bone marrow origin. BACKGROUND: Myofibroblasts play important roles in the repair process of myocardial infarct, and their origin has been assumed to be interstitial fibroblasts in the heart. However, bone marrow-derived myofibroblasts have recently been identified in pathological fibrosis in extracardiac tissues. In this study, we aimed to determine whether some of the myofibroblasts in infarcted myocardium are derived from circulating precursor cells of bone marrow origin. METHODS AND RESULTS: Bone marrow (BM) of GFP-transgenic mice was transplanted into nude rats, and their coronary arteries were occluded for 60 min and reperfused for 3 or 7 days. Non-BM-transplanted rats served as controls. At 3 days after infarction, some endothelial cells were GFP-positive, indicating that they were of bone marrow origin. Predominant cells in infarcted regions were macrophages and neutrophils, and there were only a small number of vimentin-positive cells and fewer myofibroblasts, both of which were GFP-negative. At 7 days after infarction, there were numerous myofibroblasts in granulation tissue replacing necrotic myocytes, and none of them showed GFP signals, whereas some cells were positive for both GFP and vimentin. Appearance of myofibroblasts and extent of the infarct repair in BM-transplanted and those in non-transplanted rats were similar. CONCLUSIONS: The findings in this study suggest that proliferating myofibroblasts in infarcted myocardium are derived from resident fibroblasts rather than circulating precursor cells of bone marrow origin.

Human mesenchymal stem cells xenografted directly to rat liver are differentiated into human hepatocytes without fusion.

Hepatic transdifferentiation of bone marrow cells has been previously demonstrated by intravenous administration of donor cells, which may recirculate to the liver after undergoing proliferation and differentiation in the recipient's bone marrow. In the present study, to elucidate which cellular components of human bone marrow more potently differentiate into hepatocytes, we fractionated human bone marrow cells into mesenchymal stem cells (MSCs), CD34+ cells, and non-MSCs/CD34- cells and examined them by directly xenografting to allylalcohol (AA)-treated rat liver. Hepatocyte-like cells, as revealed by positive immunostaining for human-specific alpha-fetoprotein (AFP), albumin (Alb), cytokeratin 19 (CK19), cytokeratin 18 (CK18), and asialoglycoprotein receptor (AGPR), and by reverse transcription-polymerase chain reaction (RT-PCR) for expression of AFP and Alb mRNA, were observed only in recipient livers with MSC fractions. Cell fusion was not likely involved since both human and rat chromosomes were independently identified by fluorescence in situ hybridization (FISH). The differentiation appeared to follow the process of hepatic ontogeny, reprogramming of gene expression in the genome of MSCs, as evidenced by expression of the AFP gene at an early stage and the albumin gene at a later stage. In conclusion, we have demonstrated that MSCs are the most potent component in hepatic differentiation, as revealed by directly xenografting into rat livers.

Casein enhances stability of peptides in intestinal lumen: role of digested products of casein.

PURPOSE: To investigate the inhibitory activity of casein on proteases in detail, the effect of digested products of casein itself on trypsin and chymotrypsin in rat small intestine was examined. METHODS: Male Sprague-Dawley rats weighing 200-300 g were used as the animal model. The luminal content of the jejunum was prepared, and the enzymatic activities of trypsin and chymotrypsin were determined using a specific substrate for each protease. Then, the effect of enzymatic digested products of casein on them was examined. RESULTS: The inhibitory activity of trypsin-digested casein against trypsin decreased as its digestion proceeded, but its inhibitory activity against chymotrypsin came to be more effective. On the other hand, the inhibitory activity of chymotrypsin-digested casein against chymotrypsin decreased with the degree of digestion, but no change in the inhibitory activity against trypsin was observed. Even the completely digested products of casein with trypsin or chymotrypsin showed inhibitory activities against the two proteases. CONCLUSIONS: It was suggested that not only the intact casein but also the products digested with trypsin or chymotrypsin contribute to the inhibitory effect of casein on the proteases in the intestinal lumen.

Evaluation of inhibitory activity of casein on proteases in rat intestine.

PURPOSE: To investigate the possible use of casein as an adjuvant for oral delivery of peptide drugs, the inhibitory activity of casein on proteases in rat small intestine was examined. METHODS: Male Sprague-Dawley rats weighing 200-300 g were used as the animal model. The luminal contents of the small-intestinal tract and mucosal subcellular fractions of the small intestine were prepared: the enzymatic activities of trypsin, chymotrypsin, aminopeptidase-B, leucine aminopeptidase, dipeptidylaminopeptidase-IV, cathepsin B, and dipeptidylaminopeptidase-II were determined using a specific substrate for each protease; and the effect of casein on the protease activity was examined. RESULTS: Casein strongly inhibited trypsin and chymotrypsin in the concentration-dependent manner. As to the proteases in the intestinal epithelial cells, casein inhibited an endopeptidase, cathepsin B, but not other exopeptidases. The inhibitory activity was independent of the type of casein. The kinetic analysis characterized the type of inhibition on trypsin and chymotrypsin to be competitive. CONCLUSIONS: Casein was shown to have strong inhibitory activity on trypsin and chymotrypsin in the intestinal lumen. Taken into consideration that trypsin and chymotrypsin are endopeptidases, it is suggested that casein has strong inhibitory activity only on endopeptidases.

Anti-tumor effect of chemically synthesized sulfolipids based on sea urchin's natural sulfonoquinovosylmonoacylglycerols.

We recently reported that 3'-sulfonoquinovosyl-1'-monoacylglycerol (designated A-5) extracted from sea urchin intestine was effective in suppressing the growth of solid tumors. Although the major fatty acid component of A-5 was a saturated C(16) acid, there were five other fatty acids, 14:0, 18:0, 14:1, 16:1, and 18:1, which constitute minor components of A-5. Therefore, it remains unclear as to which of these six fatty acid components of A-5 has the anti-tumor effect. In this study, we synthesized sulfolipids each containing only one of these six fatty acids and tested their cytotoxicity against tumor cells and in vivo anti-tumor effects on nude-mice bearing solid tumors of human lung adenocarcinoma cell line A-549. The IC(50) values of all products against tumor cells were more than 10(-5) M, suggesting weak cytotoxic activity compared with other chemotherapeutic compounds for cancer. On the other hand, in vivo anti-tumor assay showed that sulfoquinovosylmonoacylglycerols (SQMG) composed of 14:1 and 18:1 (designated SQMG(14:1) and SQMG(18:1), respectively) were significantly effective in suppressing the growth of solid tumors. Our data suggested that these two SQMGs had a substantial anti-tumor effect in vivo, and they are of interest as candidate drugs for anti-cancer treatment.