Numerous eosinophilic globules (skeinoid fibers) in a duodenal stromal tumor: An exceptional case showing smooth muscle differentiation

A unique case of duodenal stromal tumor In a 51-year-old man is reported. The tumor histologically showed spindle cell proliferation and numerous eosinophilic globules. Most globules were composed of tangled 45 nm thick fibrils, which were ultrastructurally Identical to 'skelnoid fibers'. The presence of glycogen granules in the tumor cells and the Immunoreactivity for α-smooth muscle actin suggested smooth muscle differentiation. Focal ultrastructural findings also supported the smooth muscle nature of this tumor. There were no immunohistochemical and ultra-structural features indicating neural differentiation. In previous studies, the presence of such 'skeinoid fibers' was suggested to be a histological marker for neural differentiation in gastrointestinal stromal tumor. However, the findings In the present case suggest that numerous 'skeinoid fibers' can be Identified in duodenal stromal tumor with smooth muscle differentiation, although this condition may be rare.     

Specific arrest of spermatogenesis caused by apoptotic cell death in transgenic mice

Background: The c-myc protooncogene has been implicated in the control of cell proliferation, differentiation and/or apoptosis in various cellular systems. However, the role of c-myc in germ cell lineage is largely unknown.
Results: We have produced transgenic mouse lines carrying the rat c-myc protooncogene under the control of human metallothionein promoter (hMT-c-myc). It was found that the male transgenic mice were sterile. In contrast, all of the female transgenic mice were completely fertile and transmitted the transgene to the next generation. However, male transgenic mice from the female transgenic founders were also found to be sterile. This sterility was due to a defect in spermatogenic cell differentiation, since virtually no sperm were seen within the seminiferous tubules or the cauda epididymis. Histological examination revealed that germ cell death occurred approximately 7 days after birth and, consequently, spermatogenesis was arrested at an early stage in meiotic division in the transgenic mice. Moreover, this germ cell death was found to be caused by apoptosis.
Conclusion: We conclude that an excess level of c-myc expression in differentiating spermatogenic cells is responsible for the apoptotic death of germ cell, and that a decrease in c-myc level would be an obligatory step for the completion of normal spermatogenesis.     

Production and characterization of monoclonal antibodies to a pilus colonization factor (colonization factor antigen III) of human enterotoxigenic Escherichia coli

Three monoclonal antibodies (MAbs) to a pilus colonization factor (colonization factor antigen III [CFA/III]) of human enterotoxigenic Escherichia coli (ETEC) were developed and characterized. All of the MAbs isolated belonged to the immunoglobulin G2a subclass. The specificity of these MAbs for CFA/III pili was demonstrated by the immunogold-labeling technique. The presence of more than one epitope in CFA/III pili was suggested. One of the three MAbs appears to recognize a polymeric conformational epitope(s) of CFA/III. CFA/III antigenicity distinct from that of other pilus colonization factors of ETEC was demonstrated by both a bacterial agglutination test and a sandwich enzyme-linked immunosorbent assay using the MAbs. Of the 100 strains of ETEC isolated from persons with traveler's diarrhea, 8% were found to carry CFA/III pili. Two enzyme-linked immunosorbent assay systems which could detect as little as several or 50 ng of CFA/III per ml were developed.     

Difference in the effects of acetazolamide and ammonium chloride acidosis on ventilatory responses to CO2 and hypoxia in humans

The effects of acetazolamide, a potent carbonic anhydrase inhibitor, and ammonium chloride (NH4Cl) on arterial blood gas tension, resting ventilation, and ventilatory responses to CO2 (HCVR) and hypoxia (HVR) were studied in healthy male subjects. Both drugs induced chronic metabolic acidosis with the reduction in plasma bicarbonate by a mean of 7.0 +/- 2.0 (S.D.) mM after acetazolamide and by 5.6 +/- 1.8 mM after NH4Cl. The ratio in the decrement of PaCO2 to that of plasma bicarbonate (delta PaCO2/delta [HCO3-]) was 1.51 in the former and 0.98 in the latter. Both drugs increased inspiratory minute ventilation (VI) predominantly due to increased tidal volume (VT) with acetazolamide and to increased respiratory frequency (f) with NH4Cl. In HCVR, the increments in CO2- ventilation slope and in ventilation at PETCO2 60 mmHg after drug administration were 0.77 +/- 0.51 l X min-1 X mmHg-1 and 20.0 +/- 11.2 l/min with acetazolamide and 0.59 +/- 0.40 l X min-1 X mmHg-1 and 8.0 +/- 2.8 l/min with NH4Cl, respectively. On the other hand, HVR both in terms of delta VI/delta SaO2 slope and of ventilation at SaO2 75% significantly increased after NH4Cl but not after acetazolamide administration. Thus, augmented VT and HCVR in the acetazolamide group and increased f and HVR in the NH4Cl group suggested that the central chemosensitive mechanism in the former and the peripheral chemosensitive mechanism in the latter may predominantly be responsible for the elevated ventilatory activities.     

Hepatoblastoma in an 82-year-old man. An autopsy case report

An autopsy case of adult hepatoblastoma is presented. The patient was an 82-year-old male with chronic hepatitis of 7 years' duration. The liver tumor was detected 6 months before death. Autopsy revealed a large hepatic tumor occupying about 80% of the entire liver. Histologically, the tumor showed typical features of mixed epithelial- and mesenchymal-type hepatoblastoma. The epithelial component consisted of fetal and embryonal cell types. The mesenchymal component showed primitive spindle-shaped cells with various degrees of cellularity. Chondroid areas and a few foci of osteoid formation were also present.     

Malignant meningioma with cartilage and giant cells.

An autopsy case of recurrent and malignant meningioma is reported. This case was originally typical benign transitional meningioma of the falx, however, the histology of the tumor changed to show malignant features during successive recurrences. At autopsy, the tumor revealed findings consistent with malignant meningioma. One of the most interesting features was the presence of cartilage and giant cells in some parts. Immunohistochemistry showed positive immunoreactivity for S-100 protein in some cartilage and giant cells and for cytokeratin in some giant cells. Multidifferential potential of the meningioma cells was suggested in this case.     

Effects of lincomycin and tetracycline on production and properties of enterotoxins of enterotoxigenic Escherichia coli

Enterotoxigenic Escherichia coli grown in the presence of lincomycin and tetracycline produced an increased amount of heat-labile enterotoxin (LT). These antibiotics increased the production of not only extracellular LT but also intracellular LT. On the other hand, lincomycin did not stimulate the production of heat-stable enterotoxin by enterotoxigenic E. coli. The extracellular LTs produced in the presence of lincomycin and tetracycline were purified and analyzed by sodium dodecyl sulfate-polyacrylamide gel disc electrophoresis. Results showed that the A subunits of the purified LTs were not nicked, unlike that of extracellular LT produced in the absence of the antibiotics.     

Production of monoclonal antibodies against thermostable direct hemolysin of Vibrio parahaemolyticus and application of the antibodies for enzyme-linked immunosorbent assay

A total nine hybridoma cell lines that produced monoclonal antibodies against thermostable direct hemolysin (Vp-TDH), a possible pathogenic toxin, of Kanagawa phenomenon-positive Vibrio parahaemolyticus was isolated and characterized. These monoclonal antibodies (mAbs) were divided into a minimum of five different specificity groups, including mAbs specific to Vp-TDH and common to Vp-TDH and Vp-TRH, a Vp-TDH-related hemolysin produced by Kanagawa phenomenon-negative V. parahaemolyticus. An enzyme-linked immunosorbent assay (ELISA) using mAb-1-D, a mAb specific for Vp-TDH, was developed for specific detection of Vp-TDH. On the other hand, the ELISA using mAb-9-D, and mAb common to both Vp-TDH and Vp-TRH, could be used for detection of both Vp-TDH and Vp-TRH. Thus, by combining these two ELISAs differential detection of Vp-TDH and Vp-TRH can be performed. Hence, the two ELISAs were applied for various strains of V. parahaemolyticus and it was found that most Kanagawa phenomenon-positive and -negative clinical isolates produced Vp-TDH and Vp-TRH, respectively, but all environmental strains, that were Kanagawa phenomenon-negative, produced neither toxin.Supported by a Grant-in-Aid for Scientific Research and a Grant-in-Aid for Developmental Scientific Research from the Ministry of Education, Science, and Culture of Japan     

Molecular cloning and expression analysis of a macrophage-colony stimulating factor receptor-like gene from rainbow trout, Oncorhynchus mykiss

The M-CSF and its receptor (M-CSFR, CSF-1R or c-fms proto-oncogene) system were initially implicated as essential in mammals for normal monocyte development as well as for pregnancy. To allow a comparison with the M-CSF and M-CSFR system of an oviparous animal, we cloned a M-CSFR-like gene from rainbow trout (Oncorhynchus mykiss). The gene was cloned from a cDNA library of head kidney. It contained an open reading frame encoding 967 amino acids with a predicted size of 109 kDa. The putative amino acid sequence of rainbow trout M-CSFR showed 54% amino acid identity to fugu (Takifugu rubripes) M-CSFR, 52% to zebrafish (Danio rerio) M-CSFR and 40% to mouse (Mus musculus) and human (Homo sapiens) M-CSFR. The M-CSFR-like gene was constitutively expressed in head kidney, kidney, intestine, spleen and blood. The gene was detected especially in the ovary of immature female rainbow trout. These results suggest that a M-CSFR-like receptor may be involved in female reproductive tracts even in an oviparous animal like fish.