Serologic and Genetic Characterization of Hantavirus from Apodemus Mice Captured in Kyonggi - do and Gangwon - do , 2001

Hantaan virus is widely distributed in Korea and has been known to cause hemorrhagic fever with renal syndrome (HFRS). Hantaviruses are carried by numerous rodent species throughout the world. Especially, the striped field mice, Apodemus agrarius, is natural host for Hantaan virus in Korea. In this study, a total 105 wild rodents of 3 species (101 of Apodemus agrarius, 2 of Eothenomys regulus, and 2 of Mus musculus) were trapped in Kyonggi and Gangwon provinces for April to June, 2001 to study serologic and genetic characterization. 8 Apodemus agrarius (7.9%) were immunofluorescent antibody (IFA) positive against Hantaan virus and Hantaan virus genome was found in 5 among 8 seropositive rodents. S gene of isolated Hantaan virus genome was amplified and directly sequenced. Based on 917 bases of S gene (411-1327 bases), 2001 Korean isolates showed 94.8% to 95.5% nucleotide homologies in comparison with prototype Hantaan virus 76-118 which was isolated from Apodemus agrarius in Korea, 1976. The partial M gene (1969-2240 bases) showed 94.1% to 100.0% nucleotide homologies in comparison with 76-118 strain. In phylogenetic analysis, 2001 Korean isolates made the distinct cluster. Therefore, Hantaan viruses isolated in 2001 were not significantly chinged in genetic level comparison with previous isolate from Korea.

Test / Retest Reliability of DPOAE and TEOAE / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Otoacoustic emissions (OAEs) are the objective and noninvasive methods to assess cochlear function. The purpose of the present study is to determine the short-term and long-term test/retest reliability of the distortion-product otoacoustic emissions (DPOAEs) and transient-evoked otoacoustic emissions (TEOAEs). MATHODS: The short-and long-term reliability of DPOAE and TEOAE were examined in 11 normally hearing adults. DPOAE were collected in two basic forms consisting of audiograms and input/output (I/O) functions and reliabilities for TEOAE level, reproducibility index and peak stimulus level were calculated. RESULTS: The result of this study showed that the reliability of DPOAE and TEOAE was generally excellent. CONCLUSIONS: The DPOAE and TEOAE are highly reliable and useful tests to monitor the cochlear function for the purpose of study or clinical use in combination with other standard tests of audiometric function.

The Effects of Middle Ear Negative Pressure on the Transiently Evoked (TEOAEs)and Distortion Product (DPOAEs) Otoacoustic Emissions / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The clinical utility of otoacoustic emissions (OAEs) has been well established in childhood hearing screenings. As middle ear negative pressure prevails in normal children, and since all OAEs must be transmitted through the middle ear before they can be measured in the ear canal, OAEs can be affected by middle ear negative pressure. The purpose of this study is to elucidate the effect of middle ear negative pressure on the detectability of OAEs. MATERIAL AND METHODS: TEOAEs were recorded for 36 ears using click before & after tonsillectomy and, or adenoidectomy (T and, or A) operations. Before & after T and or A operations, DPOAEs were generated at six geometric mean frequencies between 1-6 kHz for two different groups, Group I (40 ears) and Group II (36 ears). Group I: 3(f2/f1) ratios (1.21, 1.22 and 1.23) were used at the fixed stimulus level (70-70 dB SPL). Group II:3 stimulus levels were used (70-70 dB SPL, 60-70 dB SPL and 30-40 dB SPL). RESULTS: The negative middle ear pressure attenuated low frequency emission more than high frequency emission. CONCLUSION: Negative middle ear pressure may increase false alarm. So pneumatic otoscopy and aural immittance testing should be utilized to predict the feasibility of applying OAEs in childhood hearing screening test.

Colocalization of GABA and Glycine within the Neurons of the Rat Retina / 대한해부학회지

The role of GABA or glycine as an inhibitory neurotransmitter is well established, and GABAergic or glycinergic neurons appear to play an important role in the mammalian retinas. It has been reported that certain amacrine, bipolar, displaced amacrine and ganglion cells are consistently labeled with anti-GABA or anti-glycine antisera in the mammalian retinae so far, and it has been suggested that colocalization of GABA and glycine within the retinal neurons could be common in the mammalian retina by recent immunecytochemical and electrophysiological studies. This study was conducted to localize GABAergic and glycinergic neurons and to define whether GABA and glycine are colocalized within same retinal neurons of the rat retina by immunocytochemical method using anti-GABA and anti-glycine antisera. The results were as follows : 1. GABAergic neurons of the rat retina were amacrine, interplexiform, bipolar, displaced amacrine and ganglion cells, and processes of GABAergic neurons formed dense networks with distinct two bands in the inner plexiform layer. 2. Glycinergic neurons were amacrine, bipolar, displaced amacrine and ganglion cells,and their processes were evenly distributed as dense networks through whole inner plexiform layer. 3. 28.5% of GABA immunoreactive amacrine cells and 9.8% of GABA immunoreactive bipolar cells located in the inner nuclear layer,and 11.9% of labeled neurons located in the ganglion cell layer showed glycine immunoreactivity in the rat retina. These results demonstrate that GABA and glycine, major inhibitory neurotransmitters, are colocalized within certain amacrine and displaced amacrine cells, and a few bipolar cells, and that neurons synthesizing and utilizing both GABA and glycine as their neurotransmitters may play an unique role in the visual processing in the rat retina.

Immunocytochemical Study of Calcium Binding Protein in the Distal Nephron of Rat Kidney / 대한해부학회지

Calbindin-D28k, a vitamin D-dependent calcium binding protein, plays a cardinal role in transport of calcium in kidney. Previous studies have demonstrated calbindin-D28k immunoreactivity in the distal nephron of mammalian kidney. However, it is well known that in most species including rat and human, there is a gradual transition from the distal convoluted tubule to the cortical collecting duct, and that the connecting segment do no tclearly demarcated, because of intermingling of distal convoluted tubule cells, connecting tubule cells, principal cells and at least two configurations of intercalated cells. In this study, to identify the cell types of calbindin-D28k-positive cells in distal nephron of rat kidney, we used double immunostaining with an antibody against calbindin-D28k and antibodies against thiazide sensitive Na+/Cl- cotransporter for distal convoluted tubule or H+-ATPase for intercalated cells. In the distal convoluted tubule, most of the distal convoluted tuble cells were calbindin-D28k-positive, whereas the intercalated cells were calbindin-D28k-negative. In the connecting tubule, 68% of the cells were calbindin-D28k-positive, and about 97% of the positive cells were connecting tubule cells and only 3% of them were intercalated cells. In the cortical collecting duct, and outer medullary collecting duct of outer stripe and inner stripe, only 8.6%, 11.8% and 4.4% of cells were weak positive for calbindin-D28k respectively. These weak positive cells in the collecting duct are mainly identified as intercalated cells. These findings indicate that calbindin-D28k is involved in not only transcellular transport of calcium but also processes regulating intracellular calcium in rat kidney.

Immunocytochemical Study on Synaptic Circuitry of Glycinergic Neurons in the Rat Retina / 대한해부학회지

The role of glycine as an inhibitory neurotransmitter is well established, and glycinergic neurons appear to play an important role in the mammalian retinae[Ikeda & Sheardown, 1983 ; Bolz et al., 1985]. Though it has been reported that certain conventional and displaced amacrine cells and a few of bipolar cells are consistently labeled with anti-glycine antiserum in the mammalian retinae so far[W ssle et al., 1986 ; Pourcho & Goebel, 1987 ; Davanger et al., 1991 ; Yoo & Chung, 1992], little has been studied on the synaptic circuitry of glycinergic neurons to clarify mechanism of its action in the visual processing of the mammalian retinae. This study was conducted to localize glycinergic neurons and to define their synaptic circuitry in the rat retina by immunocytochemical method using anti -glycine antiserum. The results were as follows : 1. Glycinergic neurons of the rat retina were conventional and displaced amacrine cells, interstitial cells and bipolar cells. 2. Glycinergic amacrine cells could be subdivided into two types, that is, A II amacrine cells and other amacrine cells, according to their ultrastructures. Glycinergic A II amacrine and other amacrine cell processes comprised postsynaptic dyad at the ribbon synapse of rod bipolar axon terminals in the sublamina b of the inner plexiform layer of the retina. Glycinprgic A II amacrine cell processes made gap junctions with axon terminals of unlabeled invaginating cone bipolar cells in the sublamina b, and made chemical synapses onto axon terminals of unlabeled flat cone bipolar cells and onto dendrites of ganglion cells in the sublamina a of the inner plexiform layer. In the sublamina b of the inner plexiform layer, g1ycinergic amacrine cell processes were postsynaptic to axon terminals of unlabeled invaginating cone bipolar cells, and made chemical output synapses onto axon terminals of unlabeled invaginating cone bipolar and rod bipolar cells and onto the dendrites of ganglion cells. Such cases that pre- and post-synaptic processes of glycinergic amacrine cell processes were non- glycinergic amacrine cell processes were frequently observed throughout the inner plexiform layer. In some cases, glycinergic amacrine cell processes receiving synaptic inputs from other glycinergic amacrine cell process made synaptic outputs onto the non-glycinergic or glycinergic amacrine cell processes. 3. Glycinergic bipolar cells could be subdivided into invaginating and flat cone bipolar cells. Postsynaptic dyads of cone bipolar cells at the ribbon synapses were non-glycinergic amacrine and amacrine cell processes, glycinergic amacrine and amacrine cell processes, glycinergic amacrine and non-glycinergic amacrine cell processes, and dendrite and dendrite of ganglion cells. These results demonstrate that [1] glycinergic A II amacrine cell receiving synaptic input from rod bipolar cells inhibit flat cone bipolar cells and OFF ganglion cells via chemical synapse, and excite ON cone bipolar cells via electrical synapse ; thereby visual information in the darkness can be transmitted to ON ganglion cells via ON cone bipolar cells, and [2] glycine released from glycinergic neurons inhibits directly ON and OFF ganglion cells or indirectly ON and OFF ganglion cells via non-glycinergic amacrine or bipolar cells.

Evaluation of Recurrence of Otitis Media with Effusion Using Ultra High Frequency Audiometry / 대한이비인후과학회지

The goal of treatment in OME is normal aerated middle ear space. When the tympanogram convert to type A or C from type B in patients with OME, no further medication would be needed. But 1/3 of these patient had type B tympanogram again after 4 weeks follow up without medication. Many parameters-including age, sex, season, unilaterality, passive smoking, associated rhinitis etc-were concerned about the recurrence of OME. Ultra high frequency audiometry was added as a new parameter in recurrence of OME.