Histological study on the gingiva in PenCB poisoned beagle dogs

We examined toxic effect of PenCB and therapeutic effect of squalane on the gingiva in PenCB poisoned beagle dogs. The results obtained were as follows. 1) PenCB exerted blood level-dependent changes of epithelial cells in which appearance of intracellular vacuoles and swollen mitochondria were observed. 2) Large vacuoles might be caused by degeneration of nerve ending were observed within the supra-basal layers. 3) We could not detect the definitive improvement in the gingiva of the PenCB poisoned beagle dogs followed administration of squalane.     

Histological and radiographic study of the spheno-occipital synchondrosis in cynomolgus monkeys,Macaque Irus

The spheno-occipital synchondroses of 20 cynomolgus monkeys have been examined histologically and radiographically. The findings by these two methods have been compared and correlated with the dental age of the monkeys. The radiographic examination was carried out on the isolated clivus region while serial sections were used for histological examination. Comparison of the synchondrosis by the two methods resulted in six disagreements when the synchondroses were classified as open, partly closed or closed. It is suggested that this difficulty is due to superimposition of shadows on the radiographs and small degrees of histological union not being recognised radiographically. It is further suggested that care should be taken in determining the age at closure when radiographs alone are used as the criterion. The dental age at initial closure appeared to vary widely in some cases occurring at an early mixed dentition stage and in others as late as the adolescent dentition. The closure of the synchondrosis was not related to the eruption time of any particular tooth. The pattern of closure did not conform to the classical type, i.e., from above downwards nor indeed was any consistent pattern revealed in either the radiographs or histological sections.     

Histological study of intrahepatic cavernous transformation in a patient with primary myelofibrosis and portal venous thrombosis

Summary Cavernous transformation in the liver was examined histologically by serial section observations, in an autopsy case of portal venous thrombosis and primary myelofibrosis. Cavernous transformation was present from the hepatic hilus to medium-sized portal tracts and was composed of dilated and thin-walled vessels. Serial sections disclosed that these vascular channels were anastomotic and occasionally communicated with occluded portal venous radicles. In places they entered directly into the hepatic parenchyma without accompanying biliary or arterial elements, and also drained into the patent portal venous branches beyond the occluded segment. The study demonstrated that cavernous transformation in the liver develops as hepatopetal collaterals secondary to the portal venous obstruction. Periportal and peribiliary capillary plexus may become cavernous in the presence of portal venous occlusion.     

Methotrexate-related Epstein-Barr virus-associated lymphoproliferative disorder occurring in the gingiva of a patient with rheumatoid arthritis

It is well recognized that patients with immunodeficiency have a high risk of development of lymphoproliferative disorders (LPDs), and Epstein-Barr virus (EBV) is associated with the occurrence of LPDs. Methotrexate (MTX) is one of the common cause of iatrogenic-associated LPD, and approximately 40-50% of MTX-related LPD cases occur in extranodal sites. However, the occurrence of MTX-related LPD in the gingiva is extremely rare. Herein, we report the fourth documented case of MTX-related EBV-associated LPD occurring in the gingiva of a patient with rheumatoid arthritis (RA). A 76-year-old Japanese female with a 10-year history of RA, who was treated with MTX and infliximab, presented with a tumorous lesion in the gingiva. Biopsy of the gingiva tumor revealed diffuse proliferation of large-sized lymphoid cells with cleaved nuclei containing conspicuous nucleoli. These lymphoid cells were CD20- and EBER-positive. Therefore, a diagnosis of MTX-related EBV-associated LPD showing features of diffuse large B-cell lymphoma (DLBCL) that occurred in the gingiva was made. Although the occurrence of LPD in the oral region, as seen in the present case, is rare, the prevalence of this disorder may be on the rise due to the increased number of patients undergoing immunosuppression therapy. Moreover, immunosenescence can also be a cause of EBV-associated LPD. Therefore, recognition of the occurrence of this disorder in the oral cavity and consideration of the clinical history can facilitate the correct diagnosis.     

Histological and ultrastructural study on the subcommissural organ of Bradypus tridactylus

The subcommissural organ (SCO) of the Bradypus tridactylus was studied from the histological and ultrastructural point of view. The methods of GOMORI (alum-chromic-hematoxylin-phloxine), AZAN (M. Heidenhain), KLUVER and BARRERA (for nerve cells and myelinated fibers) and silver impregnation according to PALMGREN and CAJAL-DE CASTRO, were used. The material prepared for ultrastructural analize was submitted to the sequence of gluteraldehyde, osmium tetroxide, uranyl acetate and lead citrate. In function of the secretory phenomenon, a systematic study is made of different hystological and ultrastructural characteristics of the SCO and hypendymal rosettes, which were considered in the B. tridactylus as a morphofunctional unit. Fine vascular and nerve networks were observed, by the basal parts of the compact tubule alveolar system (hypendymal rosettes) which composes part of the SCO. Nerve fibers were seen between its cells reaching even up to the lumen, and they may end there in bulbar dilatations which seem to show secretory characteristics at the ultrastructural examination.     

Histological features of the thyroid gland in a patient with lithium induced thyrotoxicosis.

A 26 year old woman with lithium induced thyrotoxicosis is reported. The thyrotoxicosis was associated with a non-tender diffuse goitre and a low radioiodine uptake by the gland. The thyrotoxicosis was reversible and remitted on withdrawal of the drug. The histopathological alterations of the thyroid glad were characterised by extensive follicular cell disruption with no lymphocytic infiltration. It is postulated that lithium might directly damage thyroid follicular cells and that subsequent release of thyroglobulin into the circulation might be a cause of transient thyrotoxicosis.     

Analysis of PCB- and PCT-methylsulfones in the blood in yusho patients

Polychlorinated biphenyl (PCB)- and terphenyl (PCT)-methylsulfones were isolated from the blood of yusho patients sampled in 1987 and characterized by gas chromatography with mass spectrometry (GC/MS), electron capture detection (GC/ECD) and flame photometric detection (GC/FPD). GC/MS analysis for PCB-methylsulfones showed that all the blood tested (nine samples) contained the tri- and tetrachloro congeners. The concentrations of PCB-methylsulfones were estimated to be 15-120 ppb. PCT-methylsulfones detected in the same fraction, which were confirmed by GC/MS comparison with authentic samples as well as by GC/ECD and GC/FPD, consisted of tetra-, penta- and hexachloroterphenyl methylsulfone congeners. The levels of PCT-methylsulfones in six samples detected were preliminarily estimated to be 10-270 ppb, on the basis of a PCB-methylsulfone standard. Their origins and biological effects are unclear at present.