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T Himi

Publications and source records attributed to T Himi.

At least 73 records · Page 4Linked to original sources
PubMed1996

Purkinje cells express neuronal nitric oxide synthase after methylmercury administration.

To study the effects of chemical injury on the cerebellar nitric oxide synthase (NOS), we administered methylmercury chloride subcutaneously to mice, 10 mg/kg/day for 9 days. In the methylmercury-treated cerebellum. Purkinje cells were positive both for NADPH-diaphorase and for neuronal NOS. Calcium-dependent NOS activity was increased to 160% of the controls. The present study suggests the ability of Purkinje cells to produce NO through the expression of neuronal NOS.

Animals↗
PubMed1996

Lipopolysaccharide-induced nitric oxide synthase activity in cultured cerebellar granule neurons.

We examined the inducible form of nitric oxide synthase (iNOS) activity in cerebellar primary cultures enriched with granule neurons. Treatment with lipopolysaccharide (LPS) for 24 h was performed in two different cultures in which the survival of neurons was controlled by the levels of extracellular K+. Treatment of the granule neurons with the contaminating non-neuronal cells (< 5%) in a high K+ (25 mM) -containing culture medium with LPS induced four-fold NOS activity compared to that of the control, and the induced NOS activity was calcium-independent. LPS did not induce the NOS activity at all in the contaminating non-neuronal cells alone which were obtained by eliminating all the granule neurons from the culture by lowering the K+ concentration (5 mM). We conclude that the LPS-activated granule neurons can express iNOS activity and that this induction is not attributable to the contaminating nonneuronal cells.

Animals↗
PubMed1996

Effect of the duration of fasting on myocardial fluorine-18-fluorodeoxyglucose positron emission tomography images in normal males.

To evaluate the effect of the duration of fasting on myocardial fluorine-18-fluorodeoxyglucose (FDG) uptake and distribution, 16 FDG-positron emission tomography (PET) studies were performed in 7 normal volunteers under three different conditions: glucose loading, 6 h fasting and overnight fasting. In the glucose-loaded condition, all subjects had good image quality, and myocardial metabolic rates of glucose (MRGlc) were significantly higher than those in the other two conditions. In the 6 h and overnight fasting conditions, image qualities varied according to MRGlc. Although there were visually distinct regional differences with MRGlc ranging from 0.05 to 0.15 mumol/min per g, these differences were not impressive by a quantitative analysis. The ranges of MRGlc in these two fasted conditions overlapped each other. There was a significant negative linear correlation between MRGlc and serum free fatty acid levels. Thus, MRGlc and image quality in fasted normal subjects varied with the extent of the fed-to-starved transition under clinical fasting conditions (6 h to overnight), and this transition does not depend solely on the duration of fasting. These findings may explain the heterogeneity in FDG studies under fasting conditions.

Adult↗
PubMed1996

Cell adhesion molecules of experimental otitis media in the rat.

We examined the expression of cell adhesion molecules (CAM) in immune-mediated otitis media using keyhole limpet haemocyanin (KLH) in the rat, as well as the regulation of these CAM in peripheral blood polymorphonuclear leucocytes (PMN) and lymphocytes upon exposure to middle ear effusion (MEE). After general immunization, a topical antigen was introduced into the middle ear cavity. One day after exposure, CD18+ cells, primarily PMN, had maximally invaded the middle ear mucosa and mucosal epithelium. Mucosal epithelium strongly expressed intercellular adhesion molecule-1 (ICAM-1), only on the first day. The total number of cells in MEE reached a peak on day 3. On day 3, ICAM-1+ cells had reached a peak of 24.5% of the total cells. On day 2. CD18+ cells had reached a peak at 75.3% of the total cells. We examined the regulation of CAM in peripheral blood upon exposure to MEE. The percentage of fluorescent CD18+ PMN increased with MEE compared to those incubated in its absence, but those of L-selectin-positive PMN significantly decreased CAM on the surface lymphocytes did not change when incubated with MEE. The expression of CAM (CD18, ICAM-1) appears important for the initiation of otitis media. Moreover, it was thought that the interaction between the infiltrated PMN and MEE may modify the expression of CAM during the inflammatory process in the middle ear cavity.

Animals↗
PubMed1995

Induction of calcium-independent nitric oxide synthase activity in cultured cerebellar granule neurons.

Cultured cerebellar granule neurons were assayed for nitric oxide synthase (NOS) activity by measuring the conversion of L-arginine to L-citrulline. Granule neurons expressed constitutive NOS activity which was calcium-dependent. Treatment of neuron cultures for 24 h with the combined stimulation of IFN-gamma plus IL-1 beta, TNF-alpha and LPS induced NOS activity by 87-fold which was calcium-independent. We conclude that cultured cerebellar granule neurons can express both the constitutive and inducible forms of NOS activity.

Amino Acid Oxidoreductases↗
PubMed1995

Distribution of C cells in the thyroid gland with pyriform sinus fistula.

A pyriform sinus fistula can cause acute thyroiditis or recurrent infection in the neck. This fistula is believed to be a remnant of the branchial apparatus, although its origin has yet to be pinpointed. The spatial distribution of C cells in the thyroid gland was mapped by immunohistologic method in four patients with a pyriform sinus fistula. The C cells were identified immunohistologically with anticalcitonin antibody. The stained calcitonin-positive cells also crossreacted with the antibodies to carcinoembryonic antigen, chromogranin A, and neuron-specific enolase. The C cells were mainly distributed near the end of the fistula, and in three patients their concentration per unit volume of thyroid tissue was found to be inversely proportional to the distance from the end of the fistulas. Comparison of distant locations of the left-sided thyroid lobe in patients and the same region in control subjects showed a similar number of C cells. Thus this limited distribution of C cells suggested that the pyriform sinus fistula was either a remnant of the ultimobranchial body, the result of disturbed migration of the C cell in the fetus, or both.

Adult↗
PubMed1995

Cartinoid tumor of the middle ear and mastoid.

Primary cartinoid tumors in the middle ear and mastoid are rare. They are also very difficult to distinguish from adenomas and adenocarcinomas, using conventional histological stains. We present clinical, histological, immunohistochemical and ultrastructural findings of a cartinoid tumor in the middle ear and mastoid in a 40-year-old male. A soft tumor was revealed in the posterior mesotympanum and mastoid cavity, and a radical tympanomastoidectomy was performed. The tumor cells were stained by chromogranin A, and neurosecretory granules were confirmed with electron microscopy. We also review 20 previously reported cases in regard to their presentation, symptoms, signs, tumor extension, treatments, and histopathology.

Adenocarcinoma↗
PubMed1995

Reduced expression of the molecular markers of dopaminergic neuronal atrophy in the aging rat brain.

Expression of mRNAs encoding the dopamine transporter (DAT) and tyrosine hydroxylase (TH) in dopaminergic neurons of the substantia nigra (SN) was examined in young and aged Fischer 344 rats by in situ hybridization. Quantitative analysis revealed a statistically significant decline in both DAT and TH mRNA expression in 24-month-old rats in comparison to 6-month-old rats. In addition, it was noted that DAT mRNA expression tended to decrease by 18 months, while TH mRNA reduction did not occur until 24 months. The age-related loss of DAT and TH mRNA expressions was accompanied by diminished expression of mRNA for a neuronal growth-associated protein GAP-43, but not for SCG10 or alpha 1-tubulin. The loss of GAP-43 mRNA became evident when both DAT and TH gene expression declined with advanced age. Our findings indicate that DAT may be a marker of atrophy in dopamine neurons during normal aging.

Aging↗
PubMed1995

[Vestibular function in cochlear implants--prognostic factors and postoperative damage].

Eighteen patients with a 22-channel cochlear implant were evaluated both pre- and postoperatively with vestibular function tests; caloric test and body balance test using stabilometry. Preoperative promontory stimulation results and postoperative psychophysical factors of the cochlear implant showed no correlation with the preoperative vestibular function test results. The results of speech perception tests were not affected by the degree of residual vestibular function in any of the patients. However, for patients with deafness for a period of 10 to 20 years, the degree of the residual vestibular function estimated by the caloric test showed a correlation with the results of speech perception tests, significantly in the consonant recognition score. The results, not of length or the Rombberg ratio, but rather of the area of body sway, showed a correlation with the results of speech perception tests; consonant recognition, in patients with a short duration of deafness. Therefore preoperative vestibular function results may be useful as a predictive factor in postoperative speech perception; consonant recognition, for patients with a short duration of deafness. Reduced results of caloric testing after surgery were found in one of 11 patients (9%) with residual vestibular function. The occurrence of vertigo immediately after surgery was observed in 5 of 18 patients (28%), but this symptom was transient. No change in stabilometry results, pre-versus post-operatively, was observed. Thus, vestibular damage after surgery was considered to be minimal.

Adult↗
PubMed1995

Simplified PET quantitation of myocardial glucose utilization.

UNLABELLED: The purpose of this study was to validate experimentally a simple method to quantify tissue glucose utilization with the brain reference index (BRI) using 14C-deoxyglucose and assess its clinical feasibility for myocardial PET. METHODS: To validate the BRI method, glucose utilization in myocardial and skeletal muscle was studied in rats with 14C-deoxyglucose after increasing doses of oral glucose loading. To assess clinical feasibility of the method, the BRI was applied to nine patients undergoing myocardial PET and compared to rMGU measured by the deoxyglucose model of Sokoloff et al. and by Patlak graphical analysis. The normal range of myocardial FDG uptake expressed as the BRI was estimated with four normal volunteers. RESULTS: In skeletal muscle, a dose-dependent increase of glucose utilization was observed during oral glucose loading with doses up to 4 mg/g. In the myocardium, glucose utilization increased with a glucose loading dose of up to 1 mg/g without increasing further at greater glucose doses. Ratios of maximal glucose utilization in glucose-loaded rats to 19-hr fasted rats (controls), expressed as the BRI for left and right ventricular myocardium and skeletal muscle were 4.16, 3.74 and 7.39, respectively. Glucose utilization of right ventricular myocardium was approximately 70% of left ventricular myocardium for all glucose-loaded conditions. For patients, the BRI correlated with rMGU; four of these patients had a constant plasma glucose concentration. CONCLUSION: Myocardial BRI is a sensitive indicator of rMGU that does not require dynamic data acquisition or constant plasma glucose concentrations.

Animals↗
PubMed1995

[Relationship between static images of 13N ammonia positron emission tomography and left ventricular wall motion in patients with coronary artery disease].

Observed myocardial activities in static image of 13N ammonia positron emission tomography (PET) contains factors about not only myocardial blood flow but also wall motion, wall thickness and glutamine synthetase activity. Those factors may help to delineate myocardial viability in 13N ammonia static image. To assess the role of 13N ammonia static image in prediction of reversibility of regional wall motion abnormalities after revascularization, we studied 20 patients with coronary artery disease. Of these patients, 15 patients underwent successful coronary revascularization (8 PTCA, 7 CABG). Regional 13N concentration before revascularization was expressed as a percent of maximal myocardial concentration and compared with regional wall motion. Wall motion was assessed by visual analysis using left ventriculography. Regional myocardial 13N concentration in normal, hypokinetic, akinetic and dyskinetic segments was 85 +/- 9.3%, 75 +/- 11%*, 71 +/- 17%* and 58 +/- 7.7%*#+, respectively (*p < 0.05 vs. normal, #p < 0.05 vs. hypokinesis, +p < 0.05 vs. akinesis). The segments with functional improvement showed significantly higher concentration of 13N than those without functional recovery (80 +/- 9.7% vs. 67 +/- 8.3%, p < 0.05). By using an optimized threshold value for normalized 13N activities, the sensitivity and specificity reached to 67% and 100%, respectively, to predict functional recovery. Our data suggested that myocardial 13N concentration in static PET image is closely related to the left ventricular wall motion in the patients with coronary artery disease and that it has a possible value of prediction of myocardial viability.

Ammonia↗
PubMed1995

Downbeat nystagmus with compression of the medulla oblongata by the dolichoectatic vertebral arteries.

A case is reported of downbeat nystagmus associated with compression of the caudal brain stem by the dolichoectatic vertebral arteries, which was revealed by magnetic resonance imaging. Before surgery, the patient complained of oscillopsia at rest. Downbeat nystagmus was observed in the primary eye position and was increased in lateral gaze, especially to the left. Surgical repositioning of the left vertebral artery succeeded in resolving the downbeat nystagmus in the primary position within 1 month, and the nystagmus in all the other gaze positions almost completely disappeared over the subsequent months. Other ocular abnormalities also were improved after surgery. Thus, this case shows clear evidence of downbeat nystagmus arising from compression of dolichoectatic vertebral arteries to the medulla oblongata. Surgical neurovascular decompression of the dolichoectasia reverses the progression of symptoms if permanent neurologic damage has not already occurred.

Aged↗
PubMed1994

SCG10 mRNA localization in the hippocampus: comparison with other mRNAs encoding neuronal growth-associated proteins (nGAPs).

SCG10 is a nerve growth factor (NGF)-inducible, neuron-specific protein whose expression is tightly correlated with axonal and/or dendritic growth. We have recently shown that the mRNA encoding SCG10 is expressed at significant levels in certain subsets of neurons in the adult rat brain, while its expression is undetectable or negligible in other non-neuronal tissues. Here we show that regional SCG10 mRNA expression in the adult mouse brain is comparable to that in the rat, however, in the hippocampus its expression profile is distinct. In the mouse, SCG10 mRNA is expressed at high levels in pyramidal cells of CA3-CA4 sub-fields of Ammon's horn and at low levels in the CA1-CA2 sub-fields, while it is found rather uniformly throughout the pyramidal cell layer of the rat hippocampus. SCG10 mRNA is not detectable in the dentate gyrus of the mouse hippocampus, although it is expressed in the rat dentate gyrus. Comparison with other mRNAs encoding neuronal growth-associated proteins (nGAPs) such as GAP-43, MAP2, alpha 1-tubulin and stathmin suggests that dentate granule cells express a different repertoire of neuronal growth-associated genes in mouse and rat.

Animals↗
PubMed1994

Differential localization of SCG10 and p19/stathmin messenger RNAs in adult rat brain indicates distinct roles for these growth-associated proteins.

SCG10 is a developmentally regulated, growth-associated protein (GAP) that was isolated as a neuronal marker of the neural crest. It was recently found that SCG10 shares an amino acid sequence similarity with a phosphoprotein named stathmin or p19 of which phosphorylation is induced by nerve growth factor and vasoactive intestinal peptide in PC12 cells and striatal neurons, respectively. While expression of SCG10 messenger RNA dramatically decreases during postnatal development, significant levels of expression still persist into adulthood. To examine possible roles of SCG10 in the adult brain, we examined the distribution of messenger RNAs encoding SCG10 and p19/stathmin as well as GAP-43 in adult rat brain sections by northern blot, RNase protection and in situ hybridization. SCG10 transcripts are found at high levels in long-distance projecting neurons and neurons with extensive dendritic arbors, while p19/stathmin messenger RNA was weakly distributed over most brain areas. Both messenger RNAs are expressed in neuronal subpopulations but not in glia, although the overall distribution of the transcripts of these two structurally related genes is distinct. The spatial and temporal expression profiles of SCG10 messenger RNA is comparable to that of GAP-43, another neuronal GAP, in the developing nervous system, however the expression of SCG10 messenger RNA in the adult brain is distinct from that of GAP-43, especially in the hippocampus and brain stem, where the dentate granule cells and sensory and motor neurons of brainstem express SCG10 but not GAP-43. These results suggest that SCG10 may have a unique role in the neuronal growth-response of subsets of mature neurons, and that SCG10 plays a stathmin-like function at nerve terminals, to which it may be rapidly transported by means of membrane attachment due to a hydrophobic domain present in SCG10 but not in p19/stathmin. This suggests that SCG10 may play a role in structural plasticity in the adult brain.

Animals↗
PubMed1994

Quantitative analysis of soluble cell adhesion molecules in otitis media with effusion.

The levels of the soluble intercellular adhesion molecule 1 (sICAM-1) and soluble granule membrane protein-140 (sGMP-140) were measured in middle ear effusions (MEEs) of otitis media (OM) with ELISA. MEEs of chronic serous and mucoid OM in children contained significantly higher levels of sICAM-1 and sGMP-140 compared with normal serum. sGMP-140 in acute and chronic OM in children was higher than in adult chronic serous OM, and in acute purulent OM higher chronic serous OM in children. Cytologic analysis showed that the mean level of sGMP-140 was significantly higher in the neutrophil dominant group than in other groups except the few cells type. sICAM-1 showed no differences among the cytologic classifications. Copious amounts of sICAM-1 and sGMP-140 in MEEs were observed in this study, and were probably the result of shedding from the cells expressed cell adhesion molecules. These cell adhesion molecules in MEEs were thought to modify the inflammatory response in OM.

Acute Disease↗
PubMed1993

Induction of stathmin mRNA during liver regeneration.

Stathmin is a 19 kDa phosphoprotein, and is proposed to play a role in signal transduction in response to various extracellular stimuli that promote cellular growth and/or differentiation. We examined stathmin mRNA expression during development and liver regeneration in mice. Stathmin mRNA expression declined during the post-natal period and was undetected in adult liver. 36 h after partial hepatectomy, stathmin mRNA was rapidly induced and remained at elevated levels for at least 10 days. In situ hybridization experiments confirmed that stathmin mRNA expression occurred in hepatocytes. These results indicate that the stathmin gene expression appears to be repressed during the post-natal liver development, and is de-repressed by liver regeneration, which suggests that stathmin may be a good molecular marker of liver plasticity.

Aging↗
PubMed1993

Temporal bone findings in craniodiaphyseal dysplasia.

To our knowledge, this is the first description of the histopathology of the temporal bone from a case of craniodiaphyseal dysplasia. The air spaces of the mastoid, external auditory canal, and middle ear cavity are reduced by hyperostotic bone. The ossicles are also deformed by the bony overgrowth. Anomalous ossicles with hyperostosis could affect the air conduction. Even though the internal auditory canal is somewhat elongated and narrow, no labyrinthine abnormalities can be attributed to the abnormal bone. Facial nerves run through abnormal courses but the geniculate ganglion cells are not involved. The VIIIth nerve dysfunction in this case could be due to mechanical damage of the nerve fibers and/or impaired vascular supply by the hyperostosis.

Adult↗