Vesicular Glutamate Transporter 1 (VGLUT1)- and VGLUT2-containing Terminals on the Rat Jaw-closing γ-Motoneurons

Currently, compared to jaw-closing (JC) α-motoneurons, the information on the distribution and morphology of glutamatergic synapses on the jaw-closing (JC) γ-motoneurons, which may help elucidate the mechanism of isometric contraction of the JC muscle, is very limited. This study investigated the distribution and ultrastructural features of vesicular glutamate transporter 1 (VGLUT1)- and VGLUT2-immunopositive (+) axon terminals (boutons) on JC γ-motoneurons by retrograde tracing with horseradish peroxidase, electron microscopic immunocytochemistry, and quantitative analysis. About 35% of the boutons on identified JC γ-motoneurons were VGLUT+, and of those, 99% were VGLUT2+. The fraction of VGLUT1+ boutons of all boutons and the percentage of membrane of JC γ-motoneurons covered by these boutons were significantly lower than those for the JC α-motoneurons, revealed in our previous work. The bouton volume, mitochondrial volume, and active zone area of the VGLUT2+ boutons on the JC γ-motoneurons were uniformly small. These findings suggest that the JC γ-motoneurons, in contrast to the JC α-motoneurons, receive generally weak glutamatergic synaptic input almost exclusively from VGLUT2+ premotoneurons that form direct synapse with motoneurons.

Ultrastructure of Substance P Immunopositive Axons in the Human Dental Pulp

There exists very little information on the ultrastructure of substance P immunopositive (+) fibers in the human dental pulp, which may help in understanding the mechanism for substance P associated pulpal inflammatory pain. To address this issue, we investigated the presence of substance P+ fibers in the human dental pulp by light- and electron-microscopic immunohistochemistry. Light microscopy revealed that substance P+ fibers ran within neurovascular bundles in the radicular pulp and in the core of coronal pulp. They were also frequently present in the peripheral pulp. Substance P+ fibers showed beads like swellings interconnected by thin axonal strand, in a manner similar to bouton en passants and interconnecting axonal strand in the spinal cord. Electron microscopy revealed that almost all the substance P+ axons were unmyelinated. The axonal swellings of the substance P+ contained numerous clear round vesicles (40–50 nm in diameter) and many large dense-cored vesicles (80–110 nm in diameter) as well as many mitochondria. The vesicles and mitochondria were rarely observed in the thin axonal strand interconnecting the swellings. Intimate interrelationship or synaptic structure between the swellings of substance P+ axon and nearby pulpal cells or axons was not found. These findings suggest co-release of substance P and glutamate from the substance P+ pulpal axons and its action on nearby structures in a paracrine manner.

Quantitative Ultrastructural Analysis of Endings Presynaptic to the Tooth Pulp Afferent Terminals in the Trigeminal Oral Nucleus

The ultrastructural parameters related to synaptic release of endings which are presynaptic to tooth pulp afferent terminals (p-endings) were analyzed to understand the underlying mechanism for presynaptic modulation of tooth pulp afferents. Tooth pulp afferents were labelled by applying wheat-germ agglutinin conjugated horseradish peroxidase to the rat right lower incisor, whereafter electron microscopic morphometric analysis with serial section and reconstruction of p-endings in the trigeminal oral nucleus was performed. The results obtained from 15 p-endings presynaptic to 11 labeled tooth pulp afferent terminals were as follows. P-endings contained pleomorphic vesicles and made symmetrical synaptic contacts with labeled terminals. The p-endings showed small synaptic release-related ultrastructural parameters: volume, 0.82 ± 0.45 µm³ (mean ± SD); surface area, 4.50 ± 1.76 µm²; mitochondrial volume, 0.15 ± 0.07 µm³; total apposed surface area, 0.69 ± 0.24 µm²; active zone area, 0.10 ± 0.04 µm²; total vesicle number, 1045 ± 668.86; and vesicle density, 1677 ± 684/µm². The volume of the p-endings showed strong positive correlation with the following parameters: surface area (r=0.97, P<0.01), mitochondrial volume (r=0.56, P<0.05), and total vesicle number (r=0.73, P<0.05). However, the volume of p-endings did not positively correlate or was very weakly correlated with the apposed surface area (r=-0.12, P=0.675) and active zone area (r=0.46, P=0.084). These results show that some synaptic release-related ultrastructural parameters of p-endings on the tooth pulp afferent terminals follow the "size principle" of Pierce and Mendell (1993) in the trigeminal nucleus oralis, but other parameters do not. Our findings may demonstrate a characteristic feature of synaptic release associated with p-endings.

Investigation on the Frequency and Severity of Common Adverse Reactions of Japanese Encephalitis Vaccines / 소아감염

PURPOSE: To evaluate the number and severity of adverse reactions after Japanese Encephalitis (JE) vaccination in children using different vaccines (inactivated vaccine or live attenuated vaccine) and to determine the ability and safety of the vaccines to provide effective immunization for JE. METHODS: From August 2006 to February 2007, we conducted a prospective cohort study of the adverse reactions associated with JE immunization in Korea. We investigated common adverse reactions during the 4 days following immunization using telephone collaborations with four public health centers and nine pediatric clinics. RESULTS: The mean age of children receiving the inactivated vaccines and live attenuated vaccines, respectively, were 1.4 y (range: 1 to 8.5) and 1.7 y (range: 1 to 8.3). The number of children that received the inactivated vaccines was 425 (64.6%). A total of 233 (35.4%) received the live attenuated vaccines. Fourteen children (3.3%) had more than one localized adverse event with the inactivated vaccine, and six (2.6%) had more than one event with the live attenuated vaccine (P=0.607). Systemic adverse reactions occurred in 5.2% vs. 8.2%, respectively, of these groups (P=0.131). Fever was more common in the live attenuated vaccine group than in the inactivated vaccine group on the day of vaccination (P=0.026). CONCLUSIONS: The rate of adverse events in our study was even lower than that previously reported. No significant difference in outcomes between inactivated vaccine and live attenuated vaccine was found in JE-immunized children. Fever was more common in the live attenuated vaccine group than in the inactivated vaccine group on the day of vaccination.

A Survey for Understanding of Breastfeeding among Mothers with Chronic Hepatitis B Infection / 소아감염

PURPOSE: Breastfeeding should be recommended for infants born to mothers with chronic hepatitis B Infection after postexposure prophylaxis. However, high proportion of these mothers are reluctant to engage in breastfeeding in Korea. This survey was taken to identify the cause of that reluctance. Method:Questionnaires were given to mothers with chronic hepatitis B infection who were registered at the 'Hepatitis B Perinatal Transmission Prevention Program' operated by Korea Center for Disease Control and Prevention. They visited a community health center for blood sample collection and signed a consent paper. The questionnaires were sent to the mothers. Result:Among 839 mailed questionnaires, 114 were returned marked 'address unknown'. The overall reply rate was 17% (n=125). Among responders, 52% (n=62) were breastfeeding and 48% (n=60) were formula-feeding. The most influential factor for breastfeeding was the mother's own decision (75%) and the obstetrician's recommendation (17%). For formula- feeding mothers, their decisions were influenced by obstetricians (57%), and by their own thinking (28%). The relationship between breastfeeding and perinatal prophylaxis failure was recognized as 45% 'related' and 50% 'not-related'. A total of 91% of breastfeeding mothers replied that they will breast-feed again. Among formula-feeding mothers, 78% answered that they will breast-feed if they were known that 'there is no direct relationship between breastfeeding and perinatal prophylaxis failure'. Conclusion:Despite the fact that there is no direct relationship between breastfeeding and perinatal prophylaxis failure, many were reluctant to breast-feed. Healthcare professionals have influence over the mothers for decision making. It will be necessary to educate healthcare personnel so that they can make a conceptual change as well as to promote the fact to the general public.

A Familial Case of Wiskott-Aldrich Syndrome with a Hotspot Mutation in Exon 2 of the WAS Gene

The Wiskott-Aldrich syndrome (WAS) is a severe X-linked disorder characterized classically by thrombocytopenia, immunodeficiency, and eczema. The phenotype observed in this syndrome is caused by mutation in the WAS gene. Peripheral blood DNAs were isolated from an 18-month-old boy with WAS and his mother, maternal uncle, and maternal grandmother. Genetic analysis for the detection of a mutation of WAS gene was performed by polymerase chain reaction-single strand conformational polymorphism analysis (PCR-SSCP) and direct sequencing of the PCR product. In PCR-SSCP, the patient and his maternal uncle had an abnormal shift band, which was not found in normal controls, and his mother and maternal grandmother showed heterozygous bands. In direct sequencing analysis, the patient with WAS had CGC-->CAC point mutation in exon 2 that resulted in an amino acid change in codon 86 (Arg86His). The present study identified a gene mutation responsible for WAS at a mutation hotspot of the WAS gene in a Korean family.

Normal Distribution of Nitric Oxide Synthase(NOS) in the Inner Ear of Guinea Pig / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The purpose of this study is to find out the exact distribution of nitric oxide synthase (NOS) in the cochlea and vestibular organ of normal guinea pig. Nitric oxide (NO) is synthesized from L-arginine catalyzed by NOS and it activates the soluble guanyl cyclase that activates cyclic GMP from GTP. These NO/cGMP pathways are involved in the neurotransmission of the inner ear and the regulation of cochlear blood flow in physiological condition. In addition, excess NO is involved in cytotoxicity. MATERIALS AND METHOD: Five normal guinea pigs were used. Antibodies to three isoforms of NOS (nNOS, eNOS, iNOS) were utilized to stain the paraffin sections of cochlea and vestibular organ (crista and maculae utriculi). Staining patterns were compared to previous reports. RESULTS: Neuronal NOS (nNOS) was constitutively expressed in the lateral cochlear wall (stria vascularis, spiral ligament), spiral ganglion, hair cells and supporting cells in the cochlea. In the vestibular organs, hair cells were well expressed. Endothelial NOS (eNOS) was expressed in the vascular endothelium, cochlear lateral wall, basal parts of hair cells and spiral ganglion in the cochlea. Vascular endothelium and nerve fiber including nerve calyx were also prominently expressed. No inducible NOS (iNOS) was identified in any sections. CONCLUSION: Neuronal and endothelial NOS were constitutively expressed in the inner ear of normal guinea pig. This distribution can explain the role of NO in physiologic conditions, which can be used as basic data in studying the role of NO in pathologic inner ear conditions.

The Current Status of Utilization and Demand on Cancer Information in the Faculties of Medical School in Korea / 예방의학회지

OBJECTIVES: To investigate the availability and demand for overall cancer-related information, and to establish a basic plan for the construction of a cancer database and information system based on the research results from Korea. METHODS: Postal and telephone surveys were carried out, between August 2001 and November 2001, of 323 affiliated faculty professors from medical universities and colleges in Korea. The data were analyzed with descriptive statistical methods, with regard to the present status and demand for health and cancer-related information. RESULTS: Most (over 80%) subjects studied utilized the health-related information provided on Internet website from foreign countries, such as Medline, but similar comprehensive information system lacked in Korea. The construction of a cancer-related database of domestic research results was revealed to be in a great demand. Information on registration and statistics (52.8%), study results (48.5%) and study resources (37.4%) were the major ingredients required in the database. In constructing a database of the cancer-related research results, a full-text service, continuous updating of data, and the development of standardized user-friendly searching tool were regarded as the necessary components. The formulation of an information sharing system, regarding cancer-related clinical trials, was investigated as being quite feasible. CONCLUSION: This study demonstrated the great importance of cancer information systems, and much demand for an available cancer-related database based on Korean research results.

Alteration of Karyotype and Cell Cycle Induced by UVB Irradiation In Human Keratinocytes / 대한해부학회지

To investigate the change of cell cycle by genotoxic stress and rebound proliferation in human keratinocytes, the proportions of cell cycle phases were estimated with challenge of UVB irradiation (200 J/m2). With UVB irradiation cell cycle was estimated by Cell Fit program in Flowcytometer, and main change of the cell cycle was S-phase pro-longation. In karyotyping, near diploid number of chromosomes changed to hypoteraploid number. Cell cycle phase was estimated in two groups of cells, near diploid and hypoteraploid. In near dipoid cells, S-phase prolongation was specific phenomenon, while specific G0-G1 phase prolongation was shown in hypoteraploid cells which made transformed foci in culture. The new structural anomalies were del (5q21), 8p+, and t (5 : 8)(q21 : pter). Among them, del (5q21) was found in all transformed hypotetraploid cells. These data suggest that progress of cell cycle could be [G1-S-(G2-G1)-S] by UVB irradiation and deletion of 5q21 has a key role for anchorage independent growth, which is deletion of tumor suppressor gene APC locus. That is one of important mechanisms in keratinocyte transformation by UVB irradiation. With the changes of chromosome number and cell cycle, sizes of nuclei got to bigger by two times and growth rate was delayed.