Biomedical subjects

Y S Suh

Publications and source records attributed to Y S Suh.

9 recordsLinked to original sources

PubMed1999

Magnetic resonance image-based cerebellar volumetry in healthy Korean adults.

The effects of age and gender on cerebellar size have not been established yet. To understand these effects, the area of cerebellar vermis and the volume of cerebellum were measured using serial magnetic resonance images of 124 Korean adults free of neurologic symptoms and signs. Cerebellar volume of male was significantly larger than that of female, although the size of vermis did not show significant gender difference. Correlation analysis revealed that cerebellar volume was not affected by aging. Regressional analysis demonstrated that female vermis had a tendency to shrink after age of 50, whereas male vermis and total cerebellar volume in both sexes were not altered with aging. The different response of vermis with aging and maintenance of cerebellum volume need to be more explored.

Adult↗

PubMed1999

Morphologic investigation of rolling mouse Nagoya (tg(rol)/tg(rol)) cerebellar Purkinje cells: an ataxic mutant, revisited.

Rolling mouse Nagoya (rolling: tg(rol)) is a neurologic mutant mouse exhibiting severe ataxia. Two alleles of the rolling mutation, tottering (tg) and leaner(tg(la)), have been identified as mutations in the voltage-dependent calcium channel alpha1A subunit. No specific light and electron microscopic findings have been reported for the rolling mouse cerebellum except a decreased number of granule cells, while altered Purkinje cell/parallel fiber synapses have been observed in tottering and leaner cerebella. Rolling mouse cerebella were analyzed using anti-calbindin-D immunohistochemistry and transmission electron microscopy to investigate Purkinje cell morphology and synaptic contacts between Purkinje cell dendritic spines and parallel fiber varicosities. Multiple Purkinje cell dendritic spines synapsing with single parallel fiber varicosities were frequently observed in rolling cerebella. The correlation between the presence of altered Purkinje cell synapses and ataxia in rolling mice warrants further investigation.

Alleles↗

PubMed1999

DNA inoculations with HIV-1 recombinant genomes that express cytokine genes enhance HIV-1 specific immune responses.

Vaccination with HIV-1 DNA sequences induce both humoral and cellular immune responses in experimental animals. However, these responses are relatively weak and are often only transient in their nature. In order to enhance the level of HIV-1 specific immunity, we have engineered HIV-1 DNA constructs which contained various cytokine genes such as interleukin-2 (IL-2), granulocyte-macrophage colony stimulating factor (GM-CSF) and interferon-gamma (IFN-gamma) gene. These constructs have deleted the tat and nmf genes of HIV-1 to eliminate their immunosuppressive effects. Immunizations with these recombinant constructs elicited moderate proliferative T cell responses but poor antibody responses in rats. However, inoculations of HIV-1 DNA that contained the GM-CSF or the IL-2 gene significantly enhanced humoral and proliferative T cell responses, respectively. Thus, recombinant HIV-1 genomes such as those described here may increase the efficacy of DNA vaccination.

AIDS Vaccines↗

PubMed1998

MK-801, a non-competitive NMDA receptor antagonist, prevents postischemic decrease of inositol 1,4,5-trisphosphate receptor mRNA expression in mongolian gerbil brain.

Changes of inositol 1,4,5-trisphosphate receptor (IP3R) mRNA expression after transient brain ischemia and the effect of MK-801, a non-competitive N-methyl-D-aspartic acid (NMDA) receptor antagonist, on the IP3R mRNA expression was studied in mongolian gerbil brain by in situ hybridization. Transient ischemia was induced by ligating left common carotid artery for 10 min, and the animals were allowed recovery from 15 min to 24 h. MK-801 was introduced intraperitoneally 30 min before ischemia. IP3R mRNA expression was decreased in dentate gyrus and hippocampus from 90 min until 24 h after ischemia. MK-801 pretreatment prevented the change of IP3R mRNA expression after ischemia. These results suggest that IP3R mRNA expression in ischemia may be related with NMDA receptor.

Animals↗

PubMed1997

Comparison of various expression plasmids for the induction of immune response by DNA immunization.

Intramuscular injection of plasmid DNA is an efficient method to introduce a foreign gene into a live animal. We investigated several factors affecting the gene transfer efficiency and the following immune response by intramuscular injection of plasmid DNA. When the strength of several highly efficient viral promoters was compared in muscle by using the chloramphenicol acetyltransferase (CAT) gene as an indicator, cytomegalovirus (CMV) immediate early promoter was found to be stronger than any other viral promoters including Rous sarcoma virus (RSV), murine leukemia virus (SL3-3) and simian virus 40 (SV40) early promoters. Inclusion of adenovirus tripartite leader (TPL) sequences and a synthetic intron in the 5' untranslated region of mRNA moderately stimulated the CAT expression. On the other hand, the expression of encephalomyocarditis virus (EMCV) VP1 gene was greatly enhanced by the TPL sequences and an intron. The level of humoral immune response by intramuscular injection of various VP1 expression plasmids was compared. The seroconversion rate was highly dependent on the strength of the expression vector. However, the ratio of IgG1 and IgG2a immune response was not significantly variable depending on the strength of the expression vector. Also, the efficiency of the sindbis virus-based DNA vector was examined for the gene expression and immune response. Although a high level of CAT expression was obtained in muscle by using this system, VP1 was not produced as much as the conventional expression vectors. Furthermore, little humoral immune response was elicited by intramuscular injection of VP1-expressing sindbis vector, suggesting that this system was not superior to the conventional vector for DNA immunization.

Animals↗

PubMed1997

Chromosomal localization and neural distribution of voltage dependent calcium channel beta 3 subunit gene.

Voltage dependent calcium channel (VDCC) mediates the influx of free calcium ions that acts as a signal transducer. The beta 3 subunit of the VDCC regulates the activation (opening) and inactivation (closing) kinetics through phosphorylation/dephosphorylation. We isolated a genomic clone of the human VDCC beta 3 subunit from a human genomic DNA library using VDCC beta 3 cDNA as a probe. We localized VDCC beta 3 with this genomic DNA on the chromosome by fluorescent in situ hybridization, and the distribution of VDCC beta 3 in the nervous system was investigated in rats by in situ hybridization histochemistry with rat VDCC beta 3 cDNA. The gene for the VDCC beta 3 was specifically localized on human chromosome 12q13. The mRNA for the VDCC beta 3 was predominantly expressed in the nervous system. In the brain, a strong expression of VDCC beta 3 mRNA was found in the medial habenular nucleus, a high level of expression was observed in the olfactory bulb and cerebellum, and a relatively high level of VDCC beta 3 mRNA was localized in the cerebral cortex, caudate-putamen and hippocampal formation. Interestingly, this distribution pattern is very similar to that of the rbE-II, mid-low VDCC 1 subunit, and it is suspected that VDCC beta 3 and rbE-II may function together as a pair.

Animals↗

PubMed1997

Protective immunity against heterologous challenge with encephalomyocarditis virus by VP1 DNA vaccination: effect of coinjection with a granulocyte-macrophage colony stimulating factor gene.

For DNA vaccination studies, recombinant VP1 protein of encephalomyocarditis virus (EMCV) was produced from Escherichia coli, and eukaryotic VP1 expression vector, pCT-Gs-VP1, was generated and used as a DNA vaccine. Mice were immunized intramuscularly (i.m.) with pCT-Gs-VP1 in the presence or absence of plasmid DNA expressing granulocyte-macrophage colony stimulating factor (GM-CSF), and were subsequently analyzed for their anti-VP1 immune responses with recombinant VP1 in ELISA. Immunization of mice with pCT-Gs-VP1 resulted in VP1-specific immune response and 43% protection from subsequent lethal heterologous challenge of EMCV. Coinjection of mice with pCT-Gs-VP1 and plasmid DNA encoding GM-CSF was shown to increase the seroconversion rate of the immunized mice with a single DNA injection, and enhanced to a higher degree VP1-specific immunity, which appeared to result in better protection (about 80%) from lethal virus challenge. Thus, our results provide evidence for the potential use of GM-CSF to induce better immune response and resistance against viral infection in DNA vaccination.

Animals↗

PubMed1993

Integrated delivery networks. A system for the future. Genesys Health System designs and builds a patient-focused care delivery network.

St. Joseph Hospital, Flint, MI, formed Genesys Health System in 1981, affiliating with five area hospitals and a number of other healthcare organizations. In 1983 the system closed one of the hospitals. Genesys Health System's vision is described as a three-legged stool, with the integrated delivery system as the seat. That system balances on three legs: a strong primary and specialty care physician network; a financing, or insuring, mechanism; and a revolutionary hospital and delivery system with a full continuum of services across a range of institutional and home settings. Genesys has two physician joint ventures that will eventually become one as Genesys member hospitals' medical staffs merge. Member physicians are already linked by a common computer system and risk-sharing mechanisms. The physician-Genesys joint ventures have contractual arrangements with various managed care organizations. The system serves more than 50,000 persons enrolled with HealthPlus of Michigan and virtually all the 10,000 enrolled patients of Blue Care Network, the Blue Cross health maintenance organization. After evaluating the community's needs, Genesys Health System decided to build a new hospital; 439-bed Genesys Regional Medical Center at Health Park is scheduled to open in 1997. The new hospital will be the first in the United States to be designed and built using patient-focused care concepts.

Catholicism↗

PubMed1984

A study of axonal diameters and areas in lumbosacral roots and nerves in the rat.

There has been debate as to whether there is a size difference between central and peripheral processes of dorsal root ganglion cells. In the present study, the mean areas of myelinated and unmyelinated fibers are measured as 27.8 micron2 and 0.55 micron2, respectively, in peripheral nerves and 13.72 micron2 and 0.14 micron2 in dorsal roots. Thus myelinated central processes of dorsal root ganglion cells have mean areas 50% less than the mean areas of the myelinated sensory axons in the same peripheral nerves, and the mean diameters of the central myelinated axons are 30% less than the peripheral myelinated axons. The mean areas of the unmyelinated sensory axons in the dorsal roots are 25% of the mean areas of the unmyelinated sensory unmyelinated axons are 50% of the mean diameters of the unmyelinated sensory axons in the same peripheral nerves. These data indicate that both myelinated and unmyelinated central processes of dorsal root ganglion cells are smaller than the peripheral processes of these same cells for lumbosacral segments in the rat. It is shown that axonal tapering is not responsible for these striking differences. Finally, documentation of differences in myelinated fiber histograms from dorsal roots of different segments in the rat is provided.

Animals↗