Disruption of endothelial tight junctions in a patient with mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS)

An electron microscopic study revealed disruption of capillary endothelial tight junctions (TJs) in both biopsied muscle, taken at 5 years and 1 month of age, and the autopsied brain, taken at 13 years and 6 months of age, in a patient with mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) and mitochondrial DNA (mtDNA) point mutation A3243G. This endothelial barrier disruption might result in vasogenic edema and systemic lactic acidosis, possibly the critical pathology of MELAS.

Regular Feeding Plays an Important Role in Cholesterol Homeostasis Through the Liver Circadian Clock

Rationale: Peripheral clock control and the relevance of the circadian rhythm to physiology and disease are major questions in mammalian circadian biology.

Objective: We examined the physiological functions of the liver clock.

Methods and Results: We established a suppressed feeding schedule regimen constituting a high-cholesterol diet delivered every 6 hours without changes in energy and cholesterol intake. We found that rats exposed to this regimen developed hypercholesteremia. In the liver, the rhythmicity of expression of several clock genes was disrupted. Furthermore, the nocturnal expression of the CYP7A1 gene, which encodes the rate-limiting enzyme for the conversion of cholesterol to bile acids, was shifted to a diurnal pattern. Indeed, suppression of a regular feeding rhythm increased the secretion rate of very-low-density lipoprotein cholesterol from the liver and decreased the excretion of fecal bile acids.

Conclusions: Our results demonstrated that not only the amount and quality of food but also the timing of meals has crucial health implications.

Assessing the immune state of dogs suffering from pituitary gland dependent hyperadrenocorticism by determining changes in peripheral lymphocyte subsets

In order to evaluate the immune state of dogs suffering from pituitary-dependent hyperadrenocorticism (PDH), peripheral lymphocyte subsets were examined. Twenty seven PDH dogs and eight healthy control dogs were used in the current study. Eight healthy dogs served as the control group. Twenty seven PDH dogs were categorized into 4 groups based on their post serum cortisol concentrations by ACTH stimulation test: 2-5, excellent control (n = 8); 5-20, fair control (n = 7); >20, poor control (n = 4); and untreated (n = 8). Cell counts were executed with white blood cells (WBC), lymphocytes, CD3(+) (T lymphocytes), CD4(+) (Helper T lymphocytes), CD8(+) (Cytotoxic T lymphocytes), CD21(+) (B lymphocytes) cells in addition to calculating CD4(+)/CD8(+) ratio. Results indicated a significant difference in lymphocyte numbers and lymphocyte subset populations (CD3(+), CD4(+), CD8(+), and CD21(+) cells) between PDH and control dogs. Moreover, comparison of the PDH groups (excellent control; fair control; poor control; untreated) demonstrated that all groups had a significant decrease in lymphocytes numbers (CD3(+), CD4(+) and CD21(+) cell counts) as compared to control group. Meanwhile, no significant differences were observed in WBC counts and CD4(+)/CD8(+) ratio between groups. Furthermore, lymphocyte subset distribution in excellent control PDH dogs without concurrent disease (n = 4) better resembled that of control dogs as compared to PDH dogs with concurrent disease (n = 4). PDH dogs may be suffering from an immuno-depressed state as evidenced by significant differences in lymphocyte subset populations. Furthermore, treatment of both PDH and concurrent disease might improve lymphocyte subset distribution.

A Freshwater clam (Corbicula fluminea) extract reduces cholesterol level and hepatic lipids in normal rats and xenobiotics-induced hypercholesterolemic rats

We investigated whether a freshwater clam (Corbicula fluminea) extract (FCE) could improve cholesterol metabolism and hepatic lipids accumulation in rats fed xenobiotics such as chloretone. Feeding chloretone resulted in hypercholesterolemia and fatty liver. An increase in serum cholesterol, high density lipoproteins (HDL) in particular, after intake of chloretone was observed. Serum cholesterol was decreased by supplementation with FCE. Accumulation of the hepatic lipids including triacylglycerol, cholesterol, and phospholipid was significantly suppressed by supplementation with FCE. The excretion of neutral and acidic sterols into the feces was enhanced by FCE. The hepatic gene expression of cholesterol 7alpha-hydroxylase was enhanced in rats fed a FCE-containing diet. Apolipoprotein A-I gene expression in the liver, which is a major apolipoprotein of HDL, was suppressed by FCE. These results demonstrated that FCE reduced cholesterol level and hepatic lipids in normal rats and hypercholesterolemic rats fed chloretone.

Participation of the secreted dipeptidyl and tripeptidyl aminopeptidases in asaccharolytic growth of Porphyromonas gingivalis

BACKGROUND AND OBJECTIVE

Porphyromonas gingivalis secretes gingipains, endopeptidases essential for the asaccharolytic growth of this bacterium. P. gingivalis also secretes dipeptidyl aminopeptidases (DPPIV and DPP-7) and a tripeptidyl aminopeptidase (PTP-A), although their role in asaccharolytic growth is unclear. The present study was carried out to elucidate the role of these dipeptidyl/tripeptidyl aminopeptidases on the asaccharolytic growth of P. gingivalis.

MATERIAL AND METHODS

Knockout mutants for the DPPIV (dpp), dpp7 and/or PTP-A genes were constructed. Brain-heart infusion medium supplemented with sterile hemin and menadione (BHIHM) was used as a complex medium, and the minimal medium used was GA, in which the sole energy source was a mixture of immunoglobulin G and bovine serum albumin. Growth of P. gingivalis was monitored by measuring the optical density of the culture.

RESULTS

All knockout mutants for DPPIV, dpp7 and PTP-A grew as well as strain W83 in BHIHM. In GA, growth of single-knockout and double-knockout mutants was similar to that of W83, whereas growth of a triple-knockout mutant (83-47A) was reduced. We purified recombinant DPPIV and recombinant PTP-A from recombinant Escherichia coli overproducers, and purified DPP-7 from the triple-knockout mutant 83-4A. GA supplemented with the three purified dipeptidyl/tripeptidyl aminopeptidases supported the growth of 83-47A.

CONCLUSION

DPPIV, DPP-7 and PTP-A contribute to the normal growth of P. gingivalis by cleaving substrate peptides into short-chain polypeptides that are efficient energy sources for P. gingivalis.

Overexpression/enhanced kinase activity of BCR/ABL and altered expression of Notch1 induced acute leukemia in p210BCR/ABL transgenic mice

Chronic myelogenous leukemia (CML) is a hematopoietic disorder, which begins as indolent chronic phase but inevitably progresses to fatal blast crisis. p210BCR/ABL, a constitutively active tyrosine kinase, is responsible for disease initiation but molecular mechanism(s) underlying disease evolution remains largely unknown. To explore this process, we employed retroviral insertional mutagenesis to CML-exhibiting p210BCR/ABL transgenic mice (Tg). Virus infection induced acute lymphoblastic leukemia (ALL) in p210BCR/ABL Tg with a higher frequency and in a shorter latency than wild-type littermates, and inverse PCR detected two retrovirus common integration sites (CISs) in p210BCR/ABL Tg tumors. Interestingly, one CIS was the transgene itself, where retrovirus integrations induced upregulation of p210BCR/ABL and production of truncated BCR/ABL with an enhanced kinase activity. Another CIS was Notch1 gene, where retrovirus integrations resulted in overexpression of Notch1 and generation of Notch1 lacking the C-terminal region (Notch1DeltaC) associated with stable expression of its activated product, C-terminal-truncated Notch intracellular domain (NICD Delta C). In addition, generation of Tg for both p210BCR/ABL and Notch1DeltaC developed ALL in a shortened period with Stat5 activation, demonstrating the cooperative oncogenicity of Notch1DeltaC/NICD Delta C with p210BCR/ABL involving Stat5-mediated pathway. These results demonstrated that overexpression/enhanced kinase activity of BCR/ABL and altered expression of Notch1 induces acute leukemia in a transgenic model for CML.

Cell shape, cell-cell contact, cell-extracellular matrix contact and cell polarity are all required for the maximum induction of CYP2B1 and CYP2B2 gene expression by phenobarbital in adult rat cultured hepatocytes

The effect of cell shape, cell density, contact with extracellular matrix and cell polarity on the phenobarbital (PB)-induced gene expression of CYP2B1 and CYP2B2 (CYP2B1/2B2) in adult rat hepatocytes was investigated. High cell density enhanced the induction of CYP2B1/2B2 gene expression by PB. Hepatocytes cultured on EHS gel showed a spherical cell shape and highly enhanced the induction of CYP2B1/2B2 gene expression by PB. Although monolayer hepatocytes cultured on type I collagen (TIC) and type IV collagen exhibited poor induction of CYP2B1/2B2 gene expression by PB, monolayer cells on laminin showed substantial induction. The addition of soluble laminin to media did not show any effect on induction in monolayer hepatocytes cultured on TIC. Dishes coated with different concentrations of immovable laminin demonstrated complicated effects. Coating with higher concentrations of laminin resulted in greater induction of CYP2B1/2B2 gene expression by PB. On the other hand, when hepatocytes were cultured on dishes coated with lower concentrations of laminin, they became round and greater induction of CYP2B1/2B2 gene expression by PB was observed. Spherical hepatocytes cultured on low concentrations of TIC also showed highly enhanced induction of CYP2B1/2B2 gene expression by PB. EHS gel overlay to hepatocytes cultured on TIC and collagen sandwich configurations that are known to induce cell polarity enhanced the induction by PB. The induction of CYP2B1/2B2 gene expression needed cytoskeleton organization, such as actin filament, microtubule filament and intermediate filament. These results demonstrate that cell shape, cell density, contact with extracellular matrix and cell polarity all play critical roles in the induction of CYP2B1/2B2 gene expression by PB.

Effect of gamma-immunoglobulin on the asaccharolytic growth of Porphyromonas gingivalis

BACKGROUND AND OBJECTIVES

A minimal medium is indispensable for examining the growth properties of the asaccharolytic bacterium, Porphyromonas gingivalis. The purpose of the present study was to improve the widely used KGB medium to support good growth of P. gingivalis.

MATERIAL AND METHODS

Growth of P. gingivalis (W50, W83, and ATCC33277) in a minimal medium was monitored by measuring the optical density of the culture during incubation.

RESULTS

W50, W83, and ATCC33277 grew poorly with bovine serum albumin as the sole carbon and nitrogen source, and alpha-ketoglutarate had little or no effect on this poor growth. In contrast, FeCl3 improved the growth of W83 and ATCC33277; however, the use of a high concentration of FeCl3 elicited black pigmentation of the cells. Bovine gamma-immunoglobulin greatly recovered the growth defect. None of alpha-ketoglutarate, citrate, or trace metal ions, when used to supplement KGB medium, was required for growth. We determined the optimal conditions for growth, and developed a new simple minimal medium for P. gingivalis (GA medium). Growth of ATCC33277 in GA medium was dependent on gingipains; Arg-gingipains and Lys-gingipain contributed comparably to proliferation of the bacterium.

CONCLUSION

These data indicate that GA medium is currently the most reliable minimal medium for examining the growth properties of P. gingivalis.

Relationship of periodontal infection to serum antibody levels to periodontopathic bacteria and inflammatory markers in periodontitis patients with coronary heart disease

Several reports have demonstrated a possible association of periodontal infections with coronary heart disease (CHD) by elevated antibody titre to periodontopathic bacteria in CHD patients compared with non-diseased controls. Although each periodontopathic bacterium may vary in virulence for periodontitis and atherosclerosis, antibody response to multiple bacteria in CHD patients has not been understood fully. Therefore, serum levels of antibody to 12 periodontopathic bacteria together with other atherosclerotic risk markers were compared among 51 patients with CHD, 55 patients with moderate to severe chronic periodontitis and 37 healthy individuals. The antibody response was the most prevalent for Porphyromonas gingivalis, a major causative organism, in CHD as well as periodontitis patients. However, antibody positivity was different between CHD and periodontitis if the response was analysed for two different strains of P. gingivalis, namely FDC381 and Su63. While periodontitis patients were positive for both P. gingivalis FDC381 and Su63, a high frequency of antibody positivity for P. gingivalis Su63 but not for FDC381 was observed in CHD patients. The results indicate that the presence of particular periodontopathic bacteria with high virulence may affect atherogenesis. Identifying the virulence factors of P. gingivalis Su63 may gain insight into the new therapeutic modality for infection-induced deterioration of atherosclerosis.

Fat and fish intake and asthma in Japanese women: baseline data from the Osaka Maternal and Child Health Study

OBJECTIVE

It remains controversial whether the intake of n-3 polyunsaturated fatty acids and fish is preventive against asthma. This cross-sectional study investigated the relationship between fat and fish intake and the prevalence of asthma using baseline data from a prospective study.

DESIGN

The subjects were 1002 pregnant Japanese females. A diet history questionnaire was used to assess dietary habits. Current asthma and asthma after age 18 were defined as present if subjects had been treated with medications at some time in the previous 12 months and after reaching the age of 18, respectively.

RESULTS

Fish consumption was independently associated with a decreased prevalence of asthma after age 18 and current asthma. A significant inverse relationship was observed between the ratio of n-3 to n-6 polyunsaturated fatty acid intake and the prevalence of current asthma, but not asthma after age 18. Intake of total fat, saturated, monounsaturated, n-3 polyunsaturated and n-6 polyunsaturated fatty acids, cholesterol, meat, eggs or dairy products was not evidently related to either outcome for asthma.

CONCLUSION

Our results suggest that fish consumption and the high ratio of n-3 to n-6 polyunsaturated fatty acid intake may be associated with a reduced prevalence of asthma in young female Japanese adults.

Magnesium intake is inversely associated with the prevalence of tooth loss in Japanese pregnant women: the Osaka Maternal and Child Health Study

There have only been a few studies on the role of mineral intake in tooth loss. We investigated the association between mineral intake and the prevalence of tooth loss in Japan. We used the baseline data on 1002 pregnant women who were enrolled in the Osaka Maternal and Child Health Study between November 2001 and March 2003. Tooth loss was defined as the previous extraction of one or more teeth. Nutrient intake was assessed by a validated diet history questionnaire. Prevalence odds ratios and confidence intervals were estimated by applying a multiple logistic regression model. The adjusted odds ratio upon comparison of the highest quartile with the lowest quartile of magnesium intake was 0.64 (95% confidence interval, 0.42-0.99), showing a tendency for an inverse dose-response relationship (p for linear trend = 0.05). There were no associations between the level of consumption of calcium, phosphate, iron, zinc, or copper and tooth loss. The present findings suggest that intake of magnesium is related to reduced prevalence of tooth loss among young Japanese women.

Functions of sulfur-containing amino acids in lipid metabolism

It is known that plasma lipid levels are controlled not only by dietary fat and carbohydrate but also by dietary protein and amino acids. Although it used to be thought that the source of protein was important, it is known that amino acid composition, amino acids themselves, and peptides from digested protein are more important than the protein source. Sulfur-containing amino acids (SAAs) are recognized to be some of the most potent modulators of lipid metabolism among amino acids. It has been demonstrated that SAAs have an increasing effect on HDL (high-density lipoprotein)-cholesterol and a decreasing effect on VLDL (very low-density lipoprotein)-cholesterol. These data lead us to propose that SAAs have some beneficial functions against atherosclerotic diseases and metabolic syndrome. Relative availability of SAAs (RASAA) as well as the amount of SAAs in dietary protein would determine lipid metabolism. Therefore, we propose RASAA as a feasible index for improvement of lipid metabolism by amino acids. Although it is not clear how SAAs influence gene expression and lipid metabolism at a molecular level, SAAs change the metabolic pathway through transcriptional stimulation and posttranslational modification of regulatory proteins.

Lipocalin-type prostaglandin D synthase (beta-trace) is upregulated in the alphaB-crystallin-positive oligodendrocytes and astrocytes in the chronic multiple sclerosis

Lipocalin-type prostaglandin D synthase (L-PGDS), which is mainly synthesized in leptomeningeal cells and oligodendrocytes (OLs) in rodents and humans, is secreted into the human cerebrospinal fluid (CSF) as beta-trace. L-PGDS protects OLs and neurones against apoptosis in twitcher mice, a murine model of Krabbe's disease, and is the second only to a stress protein, alphaB-crystallin, as the most abundant gene product upregulated in the demyelinating focus of multiple sclerosis (MS). Here we report that although the CSF level of L-PGDS is not increased in MS patients, L-PGDS is increased in the white matter of MS patients, especially in the shadow plaque as compared with the normal white matter. L-PGDS immunoreactivity was intensely expressed in OLs within the shadow plaques and in hypertrophied astrocytes within the chronic plaques of MS patients. Both L-PGDS-positive OLs and astrocytes expressed a stress protein, alphaB-crystallin. These results suggest that the upregulation of L-PGDS occurs in OLs and astrocytes as a stress reaction.