Numerical chromosomal abnormality in gastric MALT lymphoma and diffuse large B-cell lymphoma

Background: We investigated numerical chromosomal abnormalities, using the fluorescence in situ hybridization (FISH) method, in gastric mucosa-associated lymphoid tissue (MALT) lymphoma and diffuse large B-cell lymphoma (DLBL). We also compared the histopathological findings, including the presence or absence of Helicobacter pylori infection, with the analytical results. Methods: Sixteen patients who underwent operation for malignant gastric lymphoma in our department were divided into three groups: patients with low-grade gastric MALT lymphoma (l-MALT; n = 5), those with high-grade gastric MALT lymphoma (h-MALT; n = 8), and those with DLBL (n = 3). Numerical abnormalities of chromosomes 8, 9, 12, and 17 were investigated by the FISH method, and the presence or absence of H. pylori infection was microscopically examined. Results: Numerical abnormality was observed in chromosome 12 in 11 patients (68.8%), in chromosome 8 in 10 (62.5%), and in chromosome 17 in 5 (31.3%), showing a high frequency. H. pylori infection was detected in 80% and 50% of patients with l-MALT and h-MALT, respectively, but no H. pylori infection was observed in patients with DLBL. Conclusions: A new biological characteristic of gastric MALT lymphoma was obtained, i.e., a high frequency of numerical abnormalities of chromosomes 12, 8, and 17. There was no correlation between the numerical chromosomal abnormalities and the clinicopathological findings. Received: September 5, 2001 / Accepted: February 22, 2002 Acknowledgments. We sincerely appreciate the instruction and cooperation provided by Mr. A. Furuhata, Mr. S. Nakamura, and the staff, Department of Collaborative Pathology, Juntendo University, Tokyo, Japan. Reprint requests to: I. Watanobe     

Involvement of central metastin in the regulation of preovulatory luteinizing hormone surge and estrous cyclicity in female rats

Ovulation is caused by a sequence of neuroendocrine events: GnRH and LH surges that are induced by positive feedback action of estrogen secreted by the mature ovarian follicles. The central mechanism of positive feedback action of estrogen on GnRH/LH secretion, however, is not fully understood yet. The present study examined whether metastin, the product of metastasis suppressor gene KiSS-1, is a central neuropeptide regulating GnRH/LH surge and then estrous cyclicity in the female rat. Metastin had a profound stimulation on LH secretion by acting on the preoptic area (POA), where most GnRH neurons projecting to the median eminence are located, because injection of metastin into the third ventricle or POA increased plasma LH concentrations in estrogen-primed ovariectomized rats. Metastin neurons were immunohistochemically found in the arcuate nucleus (ARC) to be colocalized with estrogen receptors with some fibers in the preoptic area (POA) in close apposition with GnRH neuronal cell bodies or fibers. Quantitative RT-PCR has revealed that KiSS-1 and GPR54 mRNAs were expressed in the ARC and POA, respectively. The blockade of local metastin action in the POA with a specific monoclonal antibody to rat metastin completely abolished proestrous LH surge and inhibited estrous cyclicity. Metastin-immunoreactive cell bodies in the ARC showed a marked increase and c-Fos expression in the early proestrus afternoon compared with the day of diestrus. Thus, metastin released in the POA is involved in inducing the preovulatory LH surge and regulating estrous cyclicity.     

Therapeutic action of 5-HT3 receptor antagonists targeting peritoneal macrophages in post-operative ileus

Background and Purpose

Post-operative ileus (POI) is induced by intestinal inflammation. Here, we aimed to clarify the effects of 5-HT₃ receptor antagonists against POI.

Experimental Approach

We administered three 5-HT₃ receptor antagonists, ondansetron, tropisetron and palonosetron, to a mouse model of POI induced by surgical intestinal manipulation (IM). Immunohistochemistry, intestinal transit, inflammatory mediator mRNA expression and 5-HT content were measured. In some experiments, 5-HT₃A receptor null mice were used.

Key Results

Three 5-HT₃ receptor antagonists reduced IM-induced infiltration of inflammatory CD68-positive macrophages and myeloperoxidase-stained neutrophils. Ondansetron exhibited no anti-inflammatory actions in 5-HT₃A receptor null mice. Ondansetron inhibited expression of the chemokine CCL2, IL-1β, IL-6, TNF-α and iNOS mRNAs up-regulated by IM, and also ameliorated the delayed gastrointestinal transit. Peritoneal macrophages, but not most infiltrating monocyte-derived macrophages, expressed 5-HT₃ receptors. IM stimulation increased the 5-HT content of peritoneal lavage fluid, which up-regulated mRNA expression of proinflammatory cytokines in peritoneal macrophages. Immunohistochemical localization of 5-HT₃ receptors suggests that ondansetron suppressed expression of these mRNAs in activated peritoneal macrophages, adhering to the serosal region of the inflamed intestinal wall.

Conclusion and Implications

5-HT₃ receptor antagonists were anti-inflammatory, mainly targeting peritoneal macrophages expressing these receptors. They also restored the delayed gastrointestinal transit by IM. 5-HT₃ receptor antagonists should be therapeutically useful agents against POI.     

Left ventricular retraining and anatomic correction in teenage patient with congenitally corrected transposition of the great arteries.

Left ventricular (LV) retraining followed by anatomical repair would be a superior alternative in patients with congenitally corrected transposition (ccTGA) having a deconditioned morphologically left ventricle (MLV); however, LV retraining in older children is a challenging task. A retraining process of the MLV in a teenage patient with ccTGA is reported here. Cardiac catheterization at 7 years of age revealed low pressure of the MLV (33/4 mm Hg) and a LV to right ventricular pressure ratio (LVp/RVp ratio) of 0.32. The first pulmonary artery banding (PAB) was performed at 10 years of age. Although the LVp/RVp ratio reached 0.68, there was no evidence of adequate LV hypertrophy. The second PAB was performed 2 years after the initial PAB, resulting in an increase in the LVp/RVp ratio to 0.93 and an adequate LV hypertrophy. The double switch procedure was successfully performed at 13 years of age. Although the ejection fraction of the MLV mildly decreased, the patient has been doing well during a follow-up period of 4 years. The MLV in the teenage patient with ccTGA was successfully trained using a retraining strategy and has sustained systemic circulation after anatomical repair.     

Keratinocyte Differentiation and Proliferation are Regulated by Adhesion to the Three-Dimensional Meshwork Structure of Type IV Collagen

We examined the behavior of human foreskin keratinocytes (HFKs) on reconstituted type IV collagen gel. HFKs survived for several days and the upper layer cells expressed a differentiation marker, involucrin. Apoptosis was induced after involucrin expression while cell proliferation was suppressed. On molecular type IV collagen, integrins shifted from α2β1 to α3β1 during HFK culture. On type IV collagen gel, HFKs initially expressed integrin α2β1, and later expressed integrin α3β1 in the presence of α2β1 did not disappear. Using synthetic peptides, we examined integrin α2-mediated adhesion to type IV collagen gel. Addition of synthetic peptide dose-dependently inhibited cell adhesion both on type IV collagen gel and on molecular type IV collagen. On type IV collagen gel, weaker phosphorylation of focal adhesion kinase, paxillin, and Akt was observed compared with the molecular forms. Based on these observations, we think type IV collagen gel is a novel culture substrate that mimics the physiological environment for HFKs.