Ultrastructure of oral sarcoma

Sarcoma of the oral region is extremely rare and ultrastructural studies of the tumor are limited in number. We collected oral sarcomas, such as fibrosarcoma, malignant fibrous histiocytoma, liposarcoma, leiomyosarcoma, rhabdomyosarcoma, angiosarcoma, alveolar soft-part sarcoma, solitary plasmacytoma, and osteosarcoma, and performed ultrastructural studies of these tumors. The value of these studies for an understanding of the biological behavior of the tumors was then investigated. In these studies, electron microscopic examinations of oral sarcoma were of assistance in our attempt to establish correct diagnosis and histogenesis. Data from the studies of oral sarcoma by light microscopy, electron microscopy, and immunohistochemistry should be accumulated.     

The distinction between Burkitt lymphoma and diffuse large B-Cell lymphoma with c-myc rearrangement.

To compare immunophenotypic and molecular features between Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL) with c-myc rearrangements (c-mycR DLBCL), we analyzed 18 cases of B-cell non-Hodgkin's lymphoma with c-mycR that were confirmed by chromosomal and/or Southern blotting analyses. The cases were histologically classified into 10 BLs and five DLBCLs. The remaining three cases could not be classified because of suboptimal quality of the surgical materials. BLs were from five adults and five children, whereas all DLBCLs were from adults. BLs were positive for CD20 (10/10 cases examined), CD10 (9/10), Bcl-2 (1/9), and Bcl-6 (10/10), whereas they were negative for CD3 (0/10) and EBV (0/8), by Epstein-Barr virus (EBV) EBER-1 RNA in situ hybridization. c-MycR DLBCLs were positive for CD20 (5/5), CD10 (2/5), Bcl-2 (3/4), and Bcl-6 (4/4), whereas none of them were positive for CD3 and EBV. A mean of MIB-1 index (MIB-1+ cells/neoplastic cells, %) of BLs (98.1%) was higher than that of c-mycR DLBCLs (66.3%; P <.0001). Somatic mutation of immunoglobulin heavy-chain gene variable region (VH gene) in BLs (four cases) ranged from 0.7 to 4.9% with an average value of 2.3%, whereas those in DLBCLs (three cases) from 8.2 to 32.0% with an average value of 17.0%. It is, therefore, concluded that a growth fraction of nearly 100%, as well as a monotonous proliferation of medium-sized cells and c-myc(R), should be of value in the diagnosis of BL, which is probably different from c-myc(R) DLBCL. In addition, CD10+, Bcl-2-, and low frequency of mutation of the VH gene could be helpful for the histologic distinction of BL from (c-mycR) DLBCL.     

Papovavirus detection by electron microscopy in the brain of an elderly patient without overt progressive multifocal leukoencephalopathy

Virions resembling papovavirus were demonstrated in glial cells in the brain of an aged patient without overt progressive multifocal leukoencephalopathy. The patient was not in a severely immunocompromised state. On histological examination, only a few tiny incomplete necrotic foci were found in the subcortical area. These foci were widely dispersed. Rare, swollen oligodendroglial cells and astrocytes in which papovavirus capsid protein (VP-1) was demonstrated immunohistochemically were present around the foci. The two typical types of virus particles i.e. 35 to 40 nm round particles and elongated particles, were observed in the nuclei of the swollen glial cells. The latter were in the minority. Distinct crystals were also found in the nuclei. The centre-to-centre distance of the particles in the crystals, about 40 nm, and the electron-opaque spots of the round-shaped virions and of the elongated particles, were indicative of structural subunits of papovavirus capsids. This case provides further evidence that papovavirus, possibly JC virus, may be reactivated in the brains of aged patients who are not in an immunocompromised state.     

The effects of nucleotides and potassium channel openers on the SUR2A/Kir6.2 complex K+ channel expressed in a mammalian cell line, HEK293T cells

 The effects of potassium channel opening drugs and intracellular nucleotides on the ATP-sensitive K+ (K_ATP) channel composed of SUR2A and Kir6.2 in HEK293T cells were examined using the patch-clamp technique. The SUR2A/Kir6.2 channel was activated effectively by pinacidil, marginally by nicorandil but not by diazoxide. The pinacidil-activated channel currents were inhibited by glibenclamide with a K _i value of 160 nM. Upon formation of inside-out (I-O) patches, spontaneous openings of the channels appeared, which were inhibited by intracellular ATP (ATP_i) equipotently in the presence and in the absence of intracellular Mg²⁺ (Mg²⁺ _i). The channel activity ran-down gradually in I-O patches. The run-down channels could be reactivated by ATP_i only in the presence of Mg²⁺ _i. Uridine 5’-diphosphate (UDP) antagonized the ATP_i-mediated inhibition of the channel activity before run-down. After run-down, UDP activated the channel without antagonizing ATP_i-mediated channel inhibition. Thus, the SUR2A/Kir6.2 reproduced the major properties of the native cardiac K_ATP channel well in terms of nucleotide regulation and pharmacology, and therefore can be a useful tool with which to elucidate the molecular mechanisms characterizing the K_ATP channel. Received: 24 October 1997 / Received after revision and accepted: 4 December 1997     

C to T transition at the first nucleotide of codon 63 of the β-globin gene corresponding to hemoglobin M-Saskatoon in an Indonesian boy

Summary Hemoglobin (Hb) M-Saskatoon, a variant of methemoglobin, is characterized by mild hemolysis. It is caused by the substitution of a histidine by a tyrosine at the 63rd amino acid residue of the -globin chain. Amplification and sequence analysis of genomic -globin DNA from an Indonesian boy diagnosed as having the more severe disease thalasemia demonstrated the presence of a C to T transition at nucleotide 473 in one of the two -blogin genes resulting in a histidine to tyrosine substitution at 63rd residue. This amino acid change matched with that reported in Hb M-Saskatoon. This nucleotide change abolished a recognition site for the restriction endonucleaseNlaIII.NalIII digestion of the corresponding -globin DNA amplified from the patient's parents indicated that the mutation was inherited through from his mother. This result shows that the world-wide distribution of Hb M-Saskatoon extends to Indonesia, where it was not previously identified. Possible causes of the unusually severe symptoms observed in the case are discussed.     

Divergent axon collaterals from fastigial oculomotor region to mesodiencephalic junction and paramedian pontine reticular formation in macaques.

Collateralization of efferent fibers from the fastigial oculomotor region (FOR) to the paramedian pontine reticular formation (PPRF) and the mesodiencephalic junction (MDJ) was studied in macaque monkeys using a fluorescent double-labeling technique. Retrogradely-labeled neurons in the contralateral FOR were examined following injections of fast blue (FB) into the MDJ and diamidino yellow (DY) into the PPRF, or vice versa. Some FOR neurons were labeled with FB, while some other FOR neurons were labeled with DY and intermingled within the FOR. While single-labeled cells in the FOR projected either to the PPRF or to the MDJ, the presence of double-labeled cells indicated that the FOR contains neurons whose axons collateralize to project to both the MDJ and PPRF. These are regarded as the preoculomotor nuclei responsible for vertical and horizontal saccades, respectively.     

Genome types of adenovirus types 19 and 37 isolated from patients with conjunctivitis in Hiroshima City

A total of 74 strains out of 33 strains of adenovirus type 19 (Ad19) plus 103 strains of type 37 (Ad37) isolated from patients with conjunctivitis at two ophthalmology clinics in Hiroshima City during the period March 1983 to December 1986 were analyzed by eight DNA restriction endonucleases in comparison with their prototype strains. All 27 Ad19 isolates examined displayed identical DNA cleavage patterns with all enzymes used (HindIII, KpnI, PstI, XhoI, BamHI, SacI, EcoRI, and SmaI), but their cleavage patterns were different from those of the prototype except with HindIII. The genome type of these isolates was tentatively named Ad19a. Forty-seven Ad37 isolates examined were divided into three genome types. They were tentatively named Ad37p, Ad37a, and Ad37b: 16 isolates (Ad37p) displayed DNA cleavage patterns identical with those of the prototype with all eight enzymes described above. Thirty isolates (Ad37a) showed the same patterns as the prototype except with EcoRI. One isolate (Ad37b) showed the same patterns as the prototype except with SmaI. The most frequently isolated genome type during the period studied was Ad37a, but the change of the predominant genome type in yearly incidences was observed.     

Binding of pseudomonal leukocidin to rabbit polymorphonuclear leukocytes.

The leukocytotoxic toxin pseudomonal leukocidin, produced by Pseudomonas aeruginosa, was radioiodinated with chloramine-T reagent. Binding of [125I]leukocidin to rabbit polymorphonuclear leukocytes was found to be concentration dependent at 37 degrees C. A Scatchard plot of binding data was linear, indicating that leukocidin binds to a single population of sites. The dissociation constant, KD, was calculated from the Scatchard plot to be 2.5 X 10(-7) M, and the number of binding sites per leukocyte was approximately 4.4 X 10(5). Unlabeled leukocidin or antileukocidin antibody reduced the binding of [125I]leukocidin to the leukocytes. A leukocidin-binding protein was extracted from rabbit polymorphonuclear leukocytes with Triton X-100 and purified by leukocidin-Sepharose 4B affinity column chromatography. Approximately 60 micrograms of binding protein was obtained from 8.1 mg of material extracted from the leukocytes. The binding protein had a molecular weight of about 50,000 as shown by sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis and staining with silver nitrate. Under nondenaturing conditions, its molecular weight was also about 50,000, as shown by gel filtration-Sephadex G-200 chromatography. The 50,000-dalton protein purified in this way from rabbit polymorphonuclear leukocytes competitively inhibited the binding of leukocidin to leukocytes and inactivated leukocidin activity. With equimolar amounts of the 50,000-dalton protein and leukocidin, up to 90% inactivation of leukocidin was observed.     

Angioarchitectural study of esophageal varices

Summary Pathomorphological and angioarchitectural characteristics of esophageal varices, mainly of ruptured varices, were studied in autopsy cases. Contrast medium was injected into the esophageal vein in 25 among 75 cases with varices, and in 4 cases without varices as a control. Out of the 75 cases with varices, rupture was confirmed in 8 cases. Ruptured points were recognized at the oral end of the longitudinal veins (these veins were called sudare-like veins in this study) in the lamina propria at the lower end of the esophagus in all of the 8 cases. This ruptured area was called the critical area. By morphometric examination, dilatation of these sudare-like veins was the most obvious in severe varices, and these veins were observed to penetrate the muscularis mucosae to connect to the submucosal veins at the critical area. This area seemed to be of the greatest significance in the pathogenesis of spontaneous variceal rupture.