Kazuyasu Baba

Odor exposure reveals non-uniform expression profiles of c-Jun protein in rat olfactory bulb neurons

In the main olfactory bulb, neurons are arranged strategically in distinct layers among which translaminar synaptic transmission can be made from the superficial, sensory to the deep, output layers that account for the processing of olfactory information. To search for stimulus-transcription coupling thought to be operated differentially in several cell types, c-Jun expression was examined immunohistochemically in rat olfactory bulb following 30-min odor stimulation with acetic acid and 1-butanol. c-Jun was rapidly induced in neuronal cell nuclei belonging to periglomerular, tufted, mitral and granule cells. The disappearance of c-Jun, however, differed between each cell type. In the glomerular layer, the glomeruli composed of c-Jun-expressing periglomerular cells were seen. Different odors led to labeling of different sets of glomeruli. The labeled periglomerular cells disappeared within 2 h. In all the deeper layers, however, a rather homogeneous label was noted for the tufted, mitral and granule cells present throughout the olfactory bulb, regardless of the difference in odor. In tufted and mitral cells, the c-Jun expression persisted for 4 days after odor stimulation. In the granule cell layer, numerous granule cells increased c-Jun immunoreactivity which lasted for 1 day following odor application. In control rats which were given clean air, the basal amount of c-Jun expression was seen confined to scattered granule cells. The results suggest that c-Jun is expressed in a variety of odorant-stimulated bulb neurons with a time course being dependent on cell type.

In situ hybridization analysis of substance P receptor in the rat retina

Substance P receptor is known to provide a principal interface between tachykinin peptides and tachykinin-sensitive cells in retinal circuitry and to produce several physiological functions such as excitation of ganglion cells. We reported results of in situ hybridization analysis of substance P receptor in rat retina using digoxigenin-labeled RNA probes to yield discrete cell labeling. Distinct hybridization signal was present in a great majority of ganglion cells that provide retinal fibers to a central target. It was also present in a subpopulation of amacrine cells. Following optic nerve crush, ganglion cells lost their hybridization signal in a time-dependent manner, while hybridization-positive amacrine cells were persistently seen. From the results, we identified the hybridization message as distinctly localized to two systems, output cells and intrinsic cells in retinal circuitry.

A subpopulation of olivocerebellar projection neurons express neuropeptide Y

By neuropeptide Y (NPY) immunohistochemistry and in situ hybridization histochemistry with digoxigenin-labeled oligonucleotide probes for this peptide, a subpopulation of neurons in the caudal portions of the rat dorsal and medial accessory olives were found to express NPY immunoreactivity and mRNA. In the cerebellum, NPY-immunolabeled climbing fibers were distributed to the flocculus and parts of vermal cortex. The results suggest particular association of NPY with the climbing fiber system presumably mediating spinal, visual and vestibular inputs.

Enkephalin-immunoreactive fastigial neurons in the rat cerebellum project to upper cervical cord segments

By using enkephalin immunohistochemistry combined with retrograde fluorescent labelling, a great majority of neurons in the rat cerebellum sending their axons to the spinal cord were shown to contain enkephalin immunoreactivity. These neurons were numerous and clustered in the fastigial nucleus but far less abundant in other cerebellar nuclei. Enkephalin-immunoreactive fibers present in the ventral horn and the central cervical nucleus of upper cervical cord segments almost completely disappeared contralaterally following kainic acid-induced cell loss in the fastigial nucleus. The results indicate that fastigial and some other cerebellar nucleus neurons provide enkephalin-containing projections toward these spinal sites.

Clinical Studies of Oral Cancer.

Seventy-three cases of oral cancer (tongue: 47, oral floor: 10, buccal mucosa: 10, gingiva: 4, hard palate: 2) treatedinitially from 1985 to 1995 were reviewed retrospectively. The cumulative five year survival rate was 71.4% for all of the patients, and 75.8% for carcinomas of the tongue, 88.9% for carcinomas of the buccal mucosa and 42.2% for carcinomas of the oral floor. Further strategies are required in advanced cases with T4 staging in order to improve the survival rate and quality of life of oral cancer patients.

Effects of Therapy of Abnormal Sensation in the Throat.

A survey was conducted of 201 patients with abnormal sensation in the throat who stopped treatment for various reasons. The respose to therapy and the psychological background were the main focuses. Anxieties about cancer at the first medical examination and desire for treatment for non-cancerous conditions were recorded. The reasons for discontinuing treatment and expectations for help from the staff, etc were considered.1. When treatment was discontinued the intensity of the abnormal sensation was 63% of that recorded at the first examination. The period of ambulatory therapy averaged 3 months.2. The response to therapy was not related to anxiety about cancer. However, the prognosis was better in patients who could ignore symptoms if cancer was ruled out than in those who wanted treatment even though cancer was not present.3. The reasons for discontinuing treatment were closely related to the degree of symptomatic improvement. Remission of symptoms was the reasons for discontinuing treatment in 27.5%; no change in symptoms was the reasons in 10.8%; in a third group some other reasons for discontinuing treatment were noted although the abnormal sensation was 74% as severe as at the first examination.The above results suggest that abnormal sensation in the throat is due to some unknown local and general factors other than psychological.