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Biomedical subjects

Y G Jeong

Publications and source records attributed to Y G Jeong.

At least 19 recordsLinked to original sources
PubMed2006

Corticotropin-releasing factor immunoreactivity increases in the cerebellar climbing fibers in the novel ataxic mutant mouse, pogo.

The ataxic pogo mouse (pogo/pogo) is a novel neurological mutant, which was derived as an inbred strain (KJR/MsKist) from a Korean wild mouse. The pathological manifestations include a difficulty in maintaining a normal posture, the failure of inter-limb coordination and an inability to walk straight. In this study, we examined the distribution of corticotropin-releasing factor (CRF) immunoreactive cerebellar climbing fibres and their projections to tyrosine hydroxylase (TH) immunoreactive Purkinje cells in the cerebellum of the pogo mutant mouse using immunohistochemistry. In the pogo/pogo mouse, a subset of climbing fibres was stained more intensely for CRF than in the control. Moreover, ataxic pogo mouse, neurons of the inferior olivary nucleus projecting climbing fibres were also more intensely stained for CRF than in the control. In the pogo/pogo mouse, TH immunoreactivity was located in the Purkinje cells, whereas no TH expression was found in the control. Double immunostaining for CRF and TH in the pogo/pogo cerebellum revealed that the distribution of TH-immunoreactive Purkinje cells corresponded to terminal fields of CRF-immunoreactive climbing fibres but not to the CRF-immunoreactive mossy fibres. Therefore, we suggest that an increase of CRF level may alter the function of targeted Purkinje cells and that it is related to the ataxic phenotype in the pogo mutant mouse.

Animals↗
PubMed2006

The absence of phosphorylated tyrosine hydroxylase expression in the purkinje cells of the ataxic mutant pogo mouse.

The pogo mouse is a new ataxic autosomal recessive mutant that arose in Korean wild mice (KJR/Mskist). Its ataxic phenotype includes difficulty in maintaining a normal posture and the inability to walk in a straight line. Several studies have reported that tyrosine hydroxylase (TH) is persistently ectopically expressed in particular subsets of Purkinje cells in a parasagittal banding pattern in several ataxic mutant mice, e.g. tottering alleles and pogo mice. In this present study, we examined the expression of an enzymatically active form of TH and phosphorylated TH at Ser(40) (phospho-TH) by using immunohistochemistry and double immunofluorescence in the cerebellum of pogo mice. TH immunostaining appeared in some Purkinje cells in pogo, but in only a few of Purkinje cells of their heterozygous littermate controls. In all groups of mice, no phospho-TH immunoreactive Purkinje cells were observed in the cerebellum, although subsets of TH immunoreactive Purkinje cells were found in adjacent sections. This study suggests that TH expression in the Purkinje cells of pogo abnormally increases without activation of this enzyme by phosphorylation. This may mean that TH in the Purkinje cells of these mutants does not catalyse the conversion of tyrosine to l-DOPA, and is not related to catecholamine synthesis.

Animals↗
PubMed2005

Post-natal changes of cyclin-dependent kinase 5 activator expression in the developing rat cerebellum.

cDNA of cyclin-dependent kinase 5 (Cdk5) was cloned based on its primary sequence homology to Cdc2 and Cdk2. Cdk5 requires the neuronal Cdk5 activators such as p35 or p39(nck5ai) (p39) for its activity. In this study, we examined post-natal changes in the p39 expression pattern during the development of the rat cerebellum. p39 began to express in somata and dendrites of Purkinje cells at post-natal day 3 (PD3). In particular, at PD12, parasagittal bands (stripes) with p39 immunoreactivity were weakly observed. At PD21, p39-immunoreactive stripes were developed when compared with the PD12 group. At this age stage, p39 immunoreactivity became weak in somata of Purkinje cells, not forming stripes. At PD28, a series of parasagittal bands were more distinct than those of the PD21 group, and p39 immunoreactivity disappeared in Purkinje cells, not forming p39 immunoreactive stripes. In the adults, p39 immunoreactivity in Purkinje cells was similar to that found in the PD28 group which showed that parasagittal bands were very narrow, and became progressively more slender. Therefore, we suggest that the post-natal changes of p39 expression in Purkinje cells in the cerebellum is an autonomous characteristic of Purkinje cells with a role of Cdk5 activators.

Animals↗
PubMed2002

Morphological characteristics of C1 and C2 adrenergic neurone groups in marmoset monkey brainstem by using antibody against phenylethanolamine-N-methyltransferase.

This work describes a mapping study of phenylethanolamine-N-methyltransferase (PNMT) immunoreactive neurones and fibres in the medulla oblongata of the marmoset monkey, Callithrix jacchus. Two groups of PNMT-immunoreactive neurones were found in the marmoset monkey medulla oblongata: a ventrolateral (C1 group) and a dorsomedial PNMT-immunoreactive cells group (C2 group). The PNMT-immunoreactive cells in the ventrolateral group C1 were found to be located around the lateral reticular nucleus. The PNMT-immunoreactive somata within the ventrolateral medulla are round to oval, and mostly multipolar with branched processes. In the dorsomedial group C2, PNMT-immunoreactive cell bodies appeared near the obex. The majority of the dorsomedial PNMT-immunoreactive neurones were observed in the nucleus tractus solitarius; although some were present in the dorsal motor nucleus of the vagus. The PNMT-immunoreactive somata in the dorsomedial medulla were small and round or ovoid. These results provide information upon the adrenergic system in the medulla oblongata of a species that presents a useful model of a small primate brain, the marmoset monkey.

Adrenergic Fibers↗
PubMed2001

Ectopic expression of tyrosine hydroxylase in Zebrin II immunoreactive Purkinje cells in the cerebellum of the ataxic mutant mouse, pogo.

The pogo mouse is a new ataxic autosomal recessive mutant that arose in an inbred strain (KJR/MsKist) derived from a Korean wild mouse. The phenotype includes difficulty in maintaining normal posture and the inability to walk straight. Several previous studies have associated inherited ataxia with the ectopic expression of tyrosine hydroxylase (TH) in Purkinje cells. Therefore, in the present study, the distribution of TH expression was compared with that of zebrin II in Purkinje cells of adult pogo/pogo mutant mice. In normal control littermates, tyrosine hydroxylase immunoreactivity is confined to a delicate axonal plexus ramifying through the molecular layer. In pogo/pogo, in addition to the axonal plexus, TH-immunoreactive Purkinje cells were present in all lobules of the cerebellar vermis and hemispheres, distributed as series parasagittal bands. The general pattern of expression is reproducible between individuals and symmetrical about the midline. Alternating stripes of TH expression are also seen in the hemispheres, and most Purkinje cells in the paraflocculi and flocculi are immunoreactive. In pogo/+ mice, TH-immunoreactive Purkinje cells are rare. The pattern of zebrin II expression was used to map TH immunoreactive Purkinje cells in pogo/pogo mutant mice. Double immunofluorescence labeling combining anti-zebrin II fand anti-TH showed that all TH-immunoreactive Purkinje cells are zebrin II+, but that many zebrin II+ Purkinje cells within a band do not stain with anti-TH. Taken together with the morphological changes observed in the Purkinje cell axons, this suggests that abnormal Purkinje cell function may contribute to the ataxic phenotype in pogo/pogo mice.

Animals↗
PubMed2001

Distribution of serotonin immunoreactivity in the main olfactory bulb of the Mongolian gerbil.

The distribution of serotonin immunoreactivity in the main olfactory bulb (MOB) of the Mongolian gerbil (Meriones unguiculatus) was examined by immunohistochemistry. Seven distinct layers of the Mongolian gerbil MOB-stained with cresyl violet were identified. Serotonin-immunoreactive (IR) cell bodies were not found in the MOB. The serotonin-IR nerve fibres had a specific laminar distribution and morphology in the gerbil MOB. Serotonin-IR nerve fibres were observed in the glomerular, external plexiform and granule cell layers of the MOB. These serotonin-IR nerve fibres showed varicosities that were larger than the thickness of the axon. The highest density of serotonin-IR nerve fibres was in glomeruli of the glomerular layer. The average fibre density in the glomerular layer was more than three to four times the density in the infraglomerular layers. Glomerular serotonin-IR fibres were much more intensively stained than infraglomerular serotonin-IR fibres. This result suggests that serotonin-IR nerve fibres of Mongolian gerbil MOB are extrinsic and may act to modulate the olfactory transmission.

Animals↗
PubMed2000

Abnormalities in cerebellar Purkinje cells in the novel ataxic mutant mouse, pogo.

The pogo mouse is a novel neurological mutant, which was discovered, in an inbred strain (KJR/MsKist) derived from a Korean wild mouse. The pathological manifestations include difficulty in maintaining normal posture, failures of interlimb coordination and the inability to walk straight. The ataxia is first apparent from about 2 weeks of age and progresses throughout life. The mutation is inherited as an autosomal recessive trait. In this report, we describe abnormalities in the pogo/pogo cerebellum. Nissl staining shows that the pogo/pogo cerebellum is normal in size and lobulation. Similarly, immunocytochemical staining for a granule cell marker, 10B5, shows no differences in the thickness of the granular layer between pogo/pogo homozygote and pogo/+ heterozygote littermate controls. By using anti-parvalbumin immunocytochemistry, the cells of molecular layer of the pogo/pogo cerebellum also appeared similar in distribution as compared to normal wild type mouse. In anti-neurofilament immunocytochemistry, the basket cells axons of the pogo/pogo cerebellum appeared normal. Purkinje cell abnormalities were identified by using anti-calbindin D immunocytochemistry. In 120-day-old pogo/pogo mutant mice there was a loss of Purkinje cells throughout the cerebellar vermis. Furthermore, the somata and dendrites were extensively vacuolated in the pogo/pogo Purkinje cells and the primary dendrites were frequently swollen. Focal axonal swellings were commonly observed in the Purkinje cell axons of pogo/pogo mutant mice as they traversed the granular layer. These data suggest that the progressive ataxia seen in pogo mice may be due to a failure of normal Purkinje cell activity.

Animals↗
PubMed2000

Abnormal synaptic organization between granule cells and Purkinje cells in the new ataxic mutant mouse, pogo.

The pogo mouse is a new ataxic mutant derived from the Korean wild mouse. The pathological manifestations include difficulty in maintaining normal posture and the inability to walk straight. The ataxia becomes apparent at about 2 weeks of age. Electron microscopic studies of the pogo/pogo homozygous cerebellum, revealed that the ectopic spines emanating from the primary dendrite of Purkinje cells were observed. Major difference between pogo/pogo homozygous and non-affected pogo/+ heterozygous was the synaptic organization of the molecular layer. Parallel fiber varicosities were larger than normal and a single fiber often established synaptic contacts with up to four dendritic spines of a Purkinje cell. This correlation between the presence of altered synaptic organization in the cerebellum and ataxia in pogo/pogo mutant mice warrants further investigation.

Animals↗
PubMed2000

The over-expression of somatostatin in the gerbil entorhinal cortex induced by seizure.

In present study, we investigated the immunohistochemical distribution of somatostatin (SRIF) in the hippocampal complex of the Mongolian gerbil and its association with different sequelae of spontaneous seizures, in an effort to identify the roles of SRIF in the self-recovery mechanisms in these animals. In the dentate gyrus and subiculum, SRIF immunoreactive (SRIF(+)) cells were similar in both the seizure resistant and the pre-seizure group of seizure sensitive gerbils. Interestingly, SRIF immunoreactivity was markedly decreased until 12 h postictal. Twenty-four hours after the on-set of seizure, the distribution of SRIF immunoreactivity in these regions had slightly increased. In contrast, in the entorhinal cortex the population of SRIF(+) cells and their density were significantly elevated compared to pre-seizure group 30 min postictal. Twelve hours after the on-set of seizure, however, the population of SRIF(+) cells and their density declined, approximately 70-80% compared to the situation at 30 min postictal. These findings suggest that the enhancement of SRIF expression in gerbil entorhinal cortex may affect tissue excitability and have a role in modulating recurrent excitation following seizures.

Animals↗
PubMed2000

Age-related change of neuropeptide Y-immunoreactive neurons in the rat main olfactory bulb.

The change of neuropeptide Y (NPY)-immunoreactive (IR) neurons in the rat main olfactory bulb as a result of aging was investigated at several aging stages over a two-year period; postnatal 1-24 months (P 1-P 24). From P 1 to P 12, the number of NPY-IR neurons and fibers increased with highest number in P 12, and the type of NPY-IR neurons had changed from bipolar neurons with short processes to bipolar/multipolar neurons with long processes. At P 24 the population of NPY-IR neurons and fibers had significantly decreased. Furthermore, the morphology of NPY-IR neurons showed a tendency to decrease in size and processes. It is suggested that the decrease of the number and size of NPY-IR neurons and fibers may underlie the age-related changes in the olfactory processes.

Aging↗
PubMed1998

Afferent innervation of the rat pancreas: retrograde tracing and immunohistochemistry in the dorsal root ganglia.

This study was undertaken to determine the segmental organization of the dorsal root ganglion (DRG) cells that give rise to pancreatic afferents containing a certain neuropeptide in the rat. These cells were examined using retrograde tracing combined with immunohistochemistry. Injection of horseradish peroxidase (HRP) into the pancreas resulted in the labeling of cells in bilateral T5-L2 DRGs, with most labeled cells lying at T10-T11. Injection into the duodenal (right), splenic (left), and entire lobes consistently produced more labeled cells significantly in the right, left, and right DRGs, respectively. Calcitonin gene-related peptide (CGRP)-, substance P (SP)-, somatostatin (SOM)-, and galanin (GAL)-immunoreactive (IR) cells in the DRGs (T9-T12) were found in -52, 17, 8, and 6%, respectively, but neuropeptide Y- and vasoactive intestinal polypeptide-IR cells were not found. About 88% of HRP-labeled cells in DRGs (T9-T12) contained CGRP, and approximately 16% of them contained SP. Although SOM- and GAL-IR cells were localized in the DRGs, these cells innervating the pancreas could not be found. In brief, these results show that bilateral (not similar in cell number on each side) DRG cells innervate the duodenal or splenic pancreas, and the majority of these cells that project to the pancreas contain CGRP and SP.

Afferent Pathways↗
PubMed1997

MR imaging of segmental renal infarction: an experimental study.

An experimental study was performed in 12 rabbits to evaluate the magnetic resonance (MR) imaging findings of segmental renal infarction. Three or four MR examinations were performed at 6 h, 1 day, 3 days, 1 week, 2 weeks, and 4 weeks following the ligation of segmental artery of the left kidney. The signal intensities of the infarcted area on both T1- and T2-weighted (T1W and T2W, respectively) images were lower than those of the non-affected area in the 6 h group, and pathological examination showed mild interstitial oedema and haemorrhage. The signal intensities of the lesion became higher on T1W images and higher or mixed on T2W scans in the 1 day group, in which the pathological findings were intense interstitial haemorrhage, interstitial oedema, and early coagulative necrosis. The signal intensities of the lesion on both pulse sequences were also higher in the 3 day and 1 week groups in which pathological examination showed progressive coagulative necrosis. The signal intensities of the lesions in the 2 and 4 week groups were lower on both pulse sequences, and the pathological finding was organizing fibrosis. Post-contrast T1W images demonstrated well the extent of the infarction in all but two cases, in which the signal intensities of the lesions were higher on pre-contrast T1W scans.

Animals↗
PubMed1995

IgA response in mice infected with Neodiplostomum seoulensis.

To observe the production of IgA in Balb/c mice with neodiplostomiasis, 20 mice were infected with each 200 metacercariae of Neodiplostomum seoulenis. Sera and the duodenums were obtained 3, 7, 14, 28 days post-infection (PI) from five mice each group. Neodiplostomum specific IgA in serum by the enzyme-linked immunosorbent assay increased from 7 days PI and persisted till 28 days PI. Immunohistochemistry for IgA was done with sections of the duodenum. The IgA-positive reaction was generally seen in the lamina propria and submucosa. Some of epithelial cells were positive at 7 and 14 days PI. The present finding showed that Neodiplostomun specific IgA antibody increased in serum and that there was local reaction of IgA in the mucosa and submucosa of the duodenum but not directly related with worm expulsion.

Animals↗
PubMed1980

Unilateral bronchial occlusion in a patient with sarcoidosis and a bronchial anomaly.

A patient with anomalous bronchial branching presented with marked stenosis and obstruction of the right mainstem bronchus due to sarcoidosis. Bronchoscopic and radiographic studies showed the right mainstem bronchus to be extensively involved with granulomatous inflammation, producing concentric cylindrical narrowing. Complete recovery occurred after one year of corticosteroid therapy.

Adult↗