Histopathologic study of the rectum in 1,438 consecutive rectal specimens in a single Japanese hospital: I. benign lesions

The author investigated histopathology of 1,438 consecutive rectal specimens in the last 10 years of our pathology laboratory in Japan. A computer review of pathologic reports was done. Observations of pathologic slides were performed, when appropriate. The rectal specimens were composed of 1,022 benign lesions and 416 malignant lesions. The 1,022 benign lesions were composed non-specific proctitis (n=460, 45%), adenoma (n=248, 24%), ulcerative colitis (n=98, 10%), hyperplastic polyp (n=54, 5%), carcinoma in adenoma (n=40, 4%), rectal ulcer (n=37, 4%), serrated adenoma (n=24, 2%), hyperplastic nodule (n=21, 2%), Crohn’s disease (n=9, 1%), ischemic proctitis (n=8, 0.8%), mucosal prolapse syndrome (n=7, 0.6%), juvenile polyp (n=6, 0.6%), lymphoid hyperplasia (n=5, 0.5%), lipoma (n=4, 0.4%) and amebic dysentery (n=2, 0.2%), and mature cystic teratoma (n=1, 0.1%). In this article, histopathological features of these benign lesions were described in details. In particular, adenomas were classified into adenomas with mild, moderate, and severe atypia, serrated adenoma, and carcinoma in adenoma. The later are mainly seen in large adenoma with severe atypia. Ulcerative colitis was characterized by continuous lesion, crypt abscess, abnormal branching, and deletion of goblet cells. Crohn’s disease was characterized by transmural inflammation and epithelioid granulomas. Ischemic colitis was characterized by ischemic necrotic changes and pseudomembrane formation. Mucosal prolapse syndrome was characterized by abnormal muscle in the mucosa (fibromuscular obliterance). Juvenile polyp was characterized by abnormal dilations of the crypts. Lymphoid hyperplasia must be differentiated from MALT lymphoma. Lipoma was ordinary lipoma without lipoblasts. Amebic dysentery was characterized by ulcer and presence of histiocyte-like entamoeba histolitica. Mature cystic teratoma was characterized by hairs and other elements of skin and mesodermal and endodermal components.     

Changes in wall shear stress magnitude after aneurysm rupture

Computational fluid dynamics (CFD) studies on cerebral aneurysms have attempted to identify surrogate hemodynamic parameters to predict rupture risk. We present a case of bilateral mirror image aneurysms, one of which ruptured soon after imaging. Wall shear stress values of the ruptured aneurysm changed by 20–30 % after rupture because of change in the aneurysm shape. Findings from our case suggest that CFD studies comparing unruptured and ruptured aneurysms may not yield valid estimation on aneurysm rupture risk because of changes in aneurysm shape after rupture. Changes in aneurysm shape after rupture should be considered in CFD research.     

Three adult cases with Corynebacterium propinquum respiratory infections in a community hospital

Corynebacterium propinquum, which is included in Corynebacterium group ANF-3, exists as a commensal in the oral flora. This organism has not yet been fully recognized as a respiratory pathogen. We previously reported that the first case with respiratory infection caused by C. propinquum. On the other hand, Corynebacterium pseudodiphtheriticum is recognized as a causative organism in respiratory infections. Recently we experienced two cases with C. propinquum respiratory infections in our hospital. Three types of the onset such as a community-acquired infection, a hospital-acquired infection, and a nursing home acquired infections were observed. Our analysis indicated that gram staining of the purulent sputum is an essential tool to evaluate whether C. propinquum is a respiratory pathogen or not, because this organism is a commensal bacteria.     

Kinetics and viral protein specificity of the cytotoxic T lymphocyte response in healthy adults immunized with live attenuated varicella vaccine.

The cytotoxic T lymphocyte (CTL) response was evaluated in adults given live attenuated varicella vaccine, using target cells expressing varicella-zoster virus (VZV) immediate-early protein (IE62) or VZV glycoproteins gpI, gpIV, or gpV to determine viral protein specificity. The frequency of CTL that recognized IE62 was 1:171,000 +/- 46,000 SE in subjects tested 10 days to 8 weeks after the initial vaccine dose; the induction of CTL specific for gpI was equivalent. CTL recognition of VZV proteins was mediated by CD4+ or CD8+ cells. CTL recognition of IE62 and gpIV persisted in vaccinees (tested approximately 4 years later) and was comparable to that in the naturally immune. The mean frequency of CTL specific for gpV was lower (but not significantly) in vaccinees than in naturally immune subjects. Assay of responder cell frequencies showed persistence of equivalent numbers of T lymphocytes that recognized IE62 and gpI in vaccinees and naturally immune subjects. Immunization with this vaccine elicited memory T lymphocyte responses to VZV comparable to those induced by natural infection.     

Fos plays no role in apoptosis of epithelia in the mouse male accessory sex organs and uterus

Roles of Fos in apoptosis of epithelia in the mouse male accessory sex organs and uterus were investigated using Fos-deficient mice. Normal 30- and 50-day-old and Fos-deficient 50-day-old male and female mice were castrated, and testosterone propionate and estradiol-17 beta were daily injected into male and female mice, respectively, for 5 days. An apoptotic index (a percentage of apoptotic cells) in the epithelium was examined from the day following the last injection (day 1) to day 8. The body weights and the weights of the ventral prostate (VP), coagulating gland (C), seminal vesicle (SV) and epididymis (Ep) and uterus of 50-day-castrated Fos-deficient mice on day 1 suggested that the development of these mice corresponded to that of 30-day-castrated normal mice at the most. The extents of apoptosis estimated by an apoptotic index in the VP, C, SV, Ep and uterus in 50-day-castrated Fos-deficient mice were comparable to those in 30-day-castrated normal mice. The extents of apoptosis in the SV, Ep and uterus in 30-day-castrated normal and 50-day-castrated Fos-deficient mice were similar to those in 50-day-castrated normal mice, while the extents of apoptosis in the VP and C in the former two groups of mice were less than those in the latter mice. The present results show that Fos-deficiency does not affect apoptosis in the SV, EP and uterus. However, the extents of apoptosis in the VP and C were less in 50-day-castrated Fos-deficient mice than in 50-day-castrated normal mice. This seems to be due to the retarded development of 50-day-castrated Fos-deficient mice, but not to a role of Fos in apoptosis.     

Targeted disruption of p70s6k defines its role in protein synthesis and rapamycin sensitivity

Here, we disrupted the p70 S6 kinase (p70^s6k) gene in murine embryonic stem cells to determine the role of this kinase in cell growth, protein synthesis, and rapamycin sensitivity. p70^s6k−/− cells proliferated at a slower rate than parental cells, suggesting that p70^s6k has a positive influence on cell proliferation but is not essential. In addition, rapamycin inhibited proliferation of p70^s6k−/− cells, indicating that other events inhibited by the drug, independent of p70^s6k, also are important for both cell proliferation and the action of rapamycin. In p70^s6k−/− cells, which exhibited no ribosomal S6 phosphorylation, translation of mRNA encoding ribosomal proteins was not increased by serum nor specifically inhibited by rapamycin. In contrast, rapamycin inhibited phosphorylation of initiation factor 4E-binding protein 1 (4E-BP1), general mRNA translation, and overall protein synthesis in p70^s6k−/− cells, indicating that these events proceed independently of p70^s6k activity. This study localizes the function of p70^s6k to ribosomal biogenesis by regulating ribosomal protein synthesis at the level of mRNA translation.