Hideo Sakashita

Olfactory disturbance induced by deafferentation of serotonergic fibers in the olfactory bulb

The serotonergic neurons of the brain stem project widely throughout the central nervous system, and the olfactory bulb is one of the major forebrain targets of the ascending serotonin pathway. According to physiological studies, neurons of the olfactory bulb were found to reduce their spontaneous discharge rates by electrophoretically applied serotonin. However, roles of the bulbar serotonin in the sense of smell remain unanswered. In the present study, using 5,7-dihydroxytryptamine, a specific neurotoxin for serotonin, we found that the conditioned rats who learned to avoid a repellent by olfaction lost ability of discrimination by deafferentation of the bulbar serotonergic fibers. Such olfactory dysfunction did not occur in the early stage (three days after injection of the toxin) when the serotonergic fibers disappeared in the bulb, but developed a few weeks later. Interestingly, histological examination revealed marked shrinkage of the bulbar glomerulus which is a major termination site of the bulbopetal serotonergic fibers, and also a synaptic site of olfactory receptor cells and bulbar output neurons. The results indicate that depletion of the serotonergic fibers in the olfactory bulb causes glomerular atrophy and olfactory disturbance in the rat.

Transection of the olfactory nerves induces expression of nerve growth factor receptor in mouse olfactory epithelium

Expression of nerve growth factor receptor (NGFR) was found in the mouse olfactory epithelium after olfactory nerve transection, although no immunoreactivity to NGFR was detectable in the olfactory epithelium in the control animals. After axotomy, however, NGFR-immunoreactive cells transiently appeared in the supporting cells, receptor neurons and basal cells between postoperative day 7 and 35, and thereafter disappeared by postoperative day 49. The results indicate that nerve growth factor may contribute to the regeneration of olfactory receptor neurons after olfactory nerve transection.

Electron microscopic study of synaptogenesis and myelination of the olfactory centers in developing rats

Development of the central olfactory system was studied in the rat with an electron microscope at three main structures: the olfactory bulb, the lateral olfactory tract, and the primary olfactory cortex (the piriform cortex). As a parameter of development, the synaptic density was examined quantitatively in the bulbar glomerulus and layer Ia (termination of bulbofugal fibers) of the piriform cortex, which are the key stations of the olfactory pathway. The synaptic densities in the glomerulus and those in layer Ia were 5.7% and 4.6% on embryonic day 19, 15.8% and 12.5% on postnatal day (P) 0, and 57.3% and 37.2% on P10, as compared with the adult (100%). As another parameter of development, the density of myelinated axons in the lateral olfactory tract was examined quantitatively. The densities of myelinated axons in the tract were 0% on P5, 15.1% on P10, and 73.5% on P21 of the adult density. Maturation in the tract was still progressing, even at P21, in terms of bundle formation and the thickness of myelin sheaths. The results show that synaptogenesis in the bulbar glomerulus is followed by synaptogenesis in layer Ia of the piriform cortex, and that myelination in the lateral olfactory tract occurs over a prolonged period, even in the stages after P21.

Branchial Cleft (Pouch) Anomalies: A Review of 42 Cases

A retrospective review was made of the medical records of 42 patients, who had had branchial cyst, sinus, or fistula, and who had been seen and treated at our hospitals. Three of these lesions were considered to have originated from the first branchial cleft, 36 from the second branchial cleft and/or pouch, and 3 from the fourth branchial pouch. There were no sex and side of presentation differences in the second branchial anomalies. However, the first branchial anomalies occurred predominantly in females, and the fourth branchial anomalies were predominantly left-sided. Pathological findings were of squamous epithelium and subepithelial lymphoid follicles in most branchial remnants. Skin, adenexa, and cartilage were observed in two first branchial cleft sinuses (Works classification Type II). Columnar epithelium (respiratory type) was observed in a second branchial pouch cyst and a second branchial fistula. All the patients with first or fourth branchial anomalies had previous infections with incision and drainage procedures, whereas only two out of 36 patients with second branchial anomalies had had previous incision procedures. All patients after complete removal of branchial anomalies have no recurrence.

Association of Epstein-Barr virus with polymorphic reticulosis

SummaryWe report a case of polymorphic reticulosis (PR) associated with pharyngeal replication of Epstein-Barr virus (EBV). A 78-year-old man with necrotic inflammatory granulations in the nasal cavities and ulcerative tissue of the tonsils was found to have PR after an initial diagnosis of lethal midline granuloma and was found to have high antibody titers to EBV. EBV-determined nuclear antigen (EBNA) was demonstrated in pharyngeal biopsy specimens by the anti-complement immunofluorescent technique, following which dual immunofluorescence staining, EBNA and T-cell antigen analysis were performed, using a wide variety of monoclonal antibodies. All of the EBNA-positive lymphocytes in the pharyngeal biopsy specimens were found to have exclusively T-cell antigens. This case strongly suggests that some of the cases of PR related to T-cell lymphomas may be closely associated with active EBV infection.

Epstein-Barr virus infection of epithelial cells derived from primary cultures of adenoidal tissue.

SummaryEpithelial cells derived from primary cultures of adenoidal tissue were exposed to Epstein-Barr virus (EBV) from the throat washings of a patient with infectious mononucleosis (IM) and P3HR-1 and B95-8 cell strains. They were then examined for EBV-specific antigens by immunofluorescence. EBV from both the P3HR-1 cell strains and the throat washings of the IM patient infected the epithelial cells at the 6th and 9th days, respectively. Although the EBV-antigen-positive cells did not increase in number and disappeared at the 12th day after infection, EBV antigens of the viruss replication cycle could still be detected in the epithelial cells shed from cell culture layer at this time. However, the virus obtained from the cell-free 12th days culture medium was incapable of transforming cord blood lymphocytes.

Osteomyelitis of Temporal Bone Associated with Tonsillar Focal Infection

We report here on two cases wherein it is conceivable that the osteomyelitis of the temporal bone was brought on by secondary complications associated with tonsillar focal infection. The main change to the bone was non-specific osteomyelitis. Cryptitis of the tonsils or fibrosis surrounding the blood vessels (onion skin lesion) was characteristic findings in the pathological studies.

Inhibitory Effects of Kampo Medicine on Epstein-Barr Virus Antigen Induction by Tumor Promoter

We have investigated the possible interaction of Japanese Kampo medicine; Shosaiko-to with Epstein-Barr virus (EBV) induction by TPA (12-O-tetra-decanoyl-phorbol-13-acetate) in EBV-genome harboring cells. The effect of ether extract of Shosaiko-to was also studied on the induction of EBV by superinfection with EBV from P3HR-1 cells (P3H-EBV). Concomitant treatment of EBV-latently-infected cells (Raji and A2L/AH) with TPA and ether extract resulted in effective inhibition of EBV-antigen induction. However, in the experiments to test the influence of ether extract on EBV induction by superinfecting Raji cells with P3H-EBV, ether extract did not affect the percentage of EBV-antigen-positive cells. These data indicate that Shosaiko-to is effective to inhibit antigen synthesis induced by chemical promoters without affecting EBV-antigen induction after superinfection.

A Case of Cervical Thymic Cyst.

A case of a thymic cyst is reported, and the literature from 1952 to 1998 was reviewed. A 19-year-old female was found to have a frontal neck mass. MRI demonstrated a cystic mass laterally to the right lobe of the thyroid gland, and pharyngography did not show a pyrif orm sinus fistula. At surgery, the cyst was found to be connected to the thymus, and was diagnosed pathologically as a cervical thymic cyst. Cervical thymic cysts are rare and clinically asymptomatic. The distributions of the age and sex of the patients are different between Japanese and Caucasian at this time.

Effects of p-Chloroamphetamine on Recovery of Olfactory Function Following Olfactory Nerve Severance in Mice

Serotonin (5-HT) can influence neurite outgrowth and neuronal differentiation, including synaptogenesis. P-chloroamphetamine (p-CA) is a commonly used drug which has been proven to cause 5-HT depletion in the central nervous system. The purpose of this investigation was to evaluate the effects of p-CA on the recovery of axotomy-induced olfactory disturbance in adult mice.