AUGMENTED ENDOGENOUS NITRIC OXIDE PRODUCTION IN PARTIAL PORTAL VEIN-LIGATED RATS

1. Endothelium-derived nitric oxide (NO) is a potent vasodilator. Because the body oxidizes it to nitrate ions, NO₃-, measurement of the serum concentration and the urinary excretion of NO₃- may be an index for endogenous NO. We investigated the role of NO on hyperdynamic circulation in cirrhotic and partial portal vein-ligated rats by measuring NO₃. 2. Liver cirrhosis was induced by administration of thioacetamide. Systemic and splanchnic haemodynamics and splenic-systemic shunting were determined by tracer microspheres. The concentration of NO₃- was measured by using high-performance liquid chromatography with an anion-column. 3. We found that systemic and splanchnic hyperdynamic circulation existed to almost the same extent in cirrhotic and in portal vein-ligated rats as compared to the controls and sham-operated rats, respectively. Splenic-systemic shunting was markedly greater in portal vein-ligated rats than in cirrhotic rats. 4. Serum NO₃- levels and urinary excretion of NO₃- in cirrhotic rats tended to increase as compared to the controls. On the other hand, the levels in portal vein-ligated rats were significantly increased as compared to those of the sham-operated rats, and were significantly and negatively correlated to the splanchnic arterial resistance and total vascular resistance. The amount of urinary excretion of NO₃- significantly correlated to splenic-systemic shunting (r = 0.61, P<0.05) only in portal vein-ligated rats. 5. We suggest that these high levels of NO₃- in portal vein-ligated rats relate to the extensive formation of porto-collateral vasculature or acute changes in systemic and splanchnic haemodynamics due to portal vein-ligation.     

Pregnancy: Oral misoprostol versus placebo for cervical dilatation before vacuum aspiration in first trimester pregnancy

Intravaginal misoprostol has been shown to be effective forcervical priming before a surgically induced abortion. The objectivewas to investigate the effectiveness of oral misoprostol incervical dilatation prior to vacuum aspiration between the 6thand 12th weeks of pregnancy. The results showed that in nulliparouspatients, the median cervical dilatation in the treatment group(7.8 mm) was significantly greater than that in the placebogroup (3.7 mm). In multiparous patients, the difference wasalso statistically significant (9.8 versus 6.0 mm). The easeof dilatation, assessed subjectively by the operating surgeons,was significantly improved in the treatment group. There wasalso a significant reduction in the duration of the operationand in the mean blood loss in the treatment group. The side-effectsencountered in the treatment group were mild and well acceptedby the women. Oral misoprostol is an effective and safe methodfor cervical dilatation prior to vacuum aspiration in firsttrimester pregnancy.     

Potentiation of allergic bronchoconstriction by repeated exposure to formaldehyde in guinea-pigs in vivo

BACKGROUND: Indoor formaldehyde (FA) might worsen allergies and be an underlying factor for the increasing incidence and severity of asthma; the exact mechanism, however, remains unclear. OBJECTIVE: The present study examined the effects of repeated exposure to FA on methacholine- and antigen-induced bronchoconstriction in guinea-pigs in vivo. METHODS: First, non-sensitized guinea-pigs were transnasally treated with 0.1 or 1.0% FA or saline three times a week for 6 weeks, and increasing concentrations of methacholine (50, 100, and 200 microg/mL) were inhaled at 5-min intervals. Second, guinea-pigs pre-treated with transnasal administration of FA or saline using the same protocol were passively sensitized with anti-ovalbumin (OA) serum 7 days before antigen challenge. Third, guinea-pigs were actively sensitized with OA and pre-treated with transnasal administration of FA or saline using the same protocol. The lateral pressure of the tracheal tube (Pao) was measured under anesthesia and artificial ventilation. RESULTS: The antigen-induced increase in Pao in actively sensitized guinea-pigs was significantly potentiated by FA exposure in a dose-dependent manner. The dose-response curve of the methacholine-induced increase in Pao in non-sensitized guinea-pigs or of the antigen-induced increase in Pao in passively sensitized guinea-pigs was not altered by FA exposure. Transnasal administration of FA significantly increased the serum anti-OA homocytotropic antibody titre (IgG) as measured by the passive cutaneous anaphylaxis reaction in actively sensitized guinea-pigs. CONCLUSION: The results suggest that repeated exposure to FA worsens allergic bronchoconstriction through enhancing antigen sensitization.     

A promoter variant of the ATP-binding cassette transporter A1 gene alters the HDL cholesterol level in the general Japanese population

To investigate the effects of polymorphisms in the ATP-binding cassette transporter A1 (ABCA1) gene on the high-density lipoprotein cholesterol (HDL-C) level and the incidence of myocardial infarction (MI), we performed association studies. Sequence analysis identified 14 polymorphisms in the promoter region of ABCA1. After considering linkage disequilibrium, three polymorphisms in the promoter region and 11 polymorphisms from the JSNP database were determined in 1,880 subjects recruited from the Suita Study, representing the general population in Japan. We evaluated the association between the ABCA1 genotype and HDL-C level adjusted not only for standard factors, but also for genetic factors including ApoA1 and ApoE genotypes. Of the 14 polymorphisms tested, the G(–273)C (P=0.0074), C(–297)T (P=0.0195), and IMS-JST071749 (P=0.0093) polymorphisms were significantly associated with the HDL-C level in the Suita population. We could reconfirm that the G(–273)C genotype was influential in another set of subjects (P=0.0310, n=743). However, the distribution of the ABCA1 G(–273)C genotype in subjects with MI (n=598) was not different from that in the control population (n=801). These results indicate that ABCA1 G(–273)C has a significant effect on the HDL-C level in the general Japanese population, but not on the incidence of MI.     

Pathological analyses of long-term intracoronary Palmaz-Schatz stenting; Is its efficacy permanent?

BACKGROUND: Angiographic regression of luminal narrowing occurs 6 months to 3 years poststenting. However, after 4 years lesions progressed gradually and late restenosis was observed in 28% of 179 Palmaz-Schatz-stented lesions during the past 10 years. Elucidating its pathogenesis is pivotal to developing preventive strategies. METHODS AND RESULTS: Histopathological and immunohistochemical studies were performed in 19 stented coronary arteries obtained from 19 patients autopsied after noncardiac death 2-7 years poststenting. The quality/severity of chronic inflammatory cells (T lymphocytes, macrophages and multinucleated giant cells) infiltration around the stent struts that is observed even in the absence of restenosis depended on the time elapsed from stenting: a) 2 years postprocedure, in spite of angiographic regression during the first year and pathologically expressed as maturation of the neointimal scar, there was chronic inflammatory response evidence: neovascularization and lymphocyte infiltration, b) > or = 3 years: the neointimal smooth muscle cells were sparse with abundant proliferation of collagen fibers. Presence of slight helper/inducer T lymphocytes and mild macrophage infiltration around the stent struts was evident immunohistochemically, c) > or = 4 years: prominent infiltration by lipid-laden macrophages with strong collagen-degrading matrix metalloproteinase immunoreactivity was observed around the struts. In two of these arteries, the surface contacting the stent was focally disrupted and covered by nonocclusive mural thrombi. CONCLUSIONS: Stainless steel stents evoke a remarkable foreign-body inflammatory reaction to the metal. These persistent peri-strut chronic inflammatory cells may accelerate new indolent atherosclerotic changes and consequent plaque vulnerability.     

Whole genome association study of rheumatoid arthritis using 27 039 microsatellites

A major goal of current human genome-wide studies is to identify the genetic basis of complex disorders. However, the availability of an unbiased, reliable, cost efficient and comprehensive methodology to analyze the entire genome for complex disease association is still largely lacking or problematic. Therefore, we have developed a practical and efficient strategy for whole genome association studies of complex diseases by charting the human genome at 100 kb intervals using a collection of 27,039 microsatellites and the DNA pooling method in three successive genomic screens of independent case-control populations. The final step in our methodology consists of fine mapping of the candidate susceptible DNA regions by single nucleotide polymorphisms (SNPs) analysis. This approach was validated upon application to rheumatoid arthritis, a destructive joint disease affecting up to 1% of the population. A total of 47 candidate regions were identified. The top seven loci, withstanding the most stringent statistical tests, were dissected down to individual genes and/or SNPs on four chromosomes, including the previously known 6p21.3-encoded Major Histocompatibility Complex gene, HLA-DRB1. Hence, microsatellite-based genome-wide association analysis complemented by end stage SNP typing provides a new tool for genetic dissection of multifactorial pathologies including common diseases.     

Nonviable Burkholderia mallei induces a mixed Th1- and Th2-like cytokine response in BALB/c mice

Nonviable cell preparations of Burkholderia mallei, the causative agent of glanders, were evaluated as potential vaccine candidates in a BALB/c murine model. Three different B. mallei cell preparations plus Alhydrogel were evaluated: a heat-killed preparation, an irradiation-inactivated preparation, and a preparation of a capsule-negative mutant strain which had been irradiation inactivated. BALB/c mice were vaccinated twice with the different B. mallei preparations, and spleens and sera were collected to determine their cellular and humoral immune responses. All three bacterial cell preparations had essentially the same results in two cellular immune response assays. In a splenocyte proliferation assay, the amount of cell proliferation in response to the homologous immunogen, concanavalin A, or lipopolysaccharide was similar for all the cell preparations. Also, splenocytes from the inoculated mice expressed interleukin 2 (IL-2), gamma interferon, and small amounts of IL-4 and IL-5, and more IL-10 cytokine in the presence of the homologous antigen. When the immunoglobulin subclasses from these mice were examined, they all produced higher levels of IgG1 than IgG2a subclasses. The higher ratio of IgG1 to IgG2a was not due to the amount of the immunogen or the adjuvant (Alhydrogel) used in the BALB/c mice. The cell preparations did not protect the vaccinated mice from a live challenge (>300 50% lethal doses). Our results suggest that in BALB/c mice, a mixed T-helper-cell-like response to nonviable B. mallei is obtained, as demonstrated by a Th1- and Th2-like cytokine response and a Th2-like subclass immunoglobulin response. This may be the reason for the inability of the B. mallei cells that were examined as candidate vaccines to protect the mice from a live challenge.     

Notch-RBP-J signaling is involved in cell fate determination of marginal zone B cells

RBP-J is a key mediator of Notch signaling that regulates cell fate determination in various lineages. To investigate the function of Notch-RBP-J in mature B cell differentiation, we generated mice that selectively lacked B cell RBP-J expression using conditional mutagenesis. Absence of RBP-J led to the loss of marginal zone B (MZB) cells with a concomitant increase in follicular B cells; in contrast, B1 cells in the peritoneal cavity were unaffected. Lack of RBP-J caused no defects in B cells maintenance, survival, plasma cell differentiation or activation. It is therefore likely that Notch-RBP-J signaling regulates the lineage commitment of mature B cells into follicular versus MZB cells. In addition, in mice with RBP-J-deficient B cells, had no obvious changes in immunoglobulin production in response to Ficoll, lipopolysaccharide or chicken gammaglobulin. In contrast, these mice exhibited increased mortality rates after blood-borne bacterial infection, which indicates that MZB cells play pivotal roles in the clearance of these bacteria.