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Biomedical subjects

H Ryu

Publications and source records attributed to H Ryu.

At least 55 records · Page 3Linked to original sources
PubMed1997

Involvement of intracellular Ca2+ during growth hormone-induced priming of human neutrophils.

Growth hormone (GH) primes and augments O2- production in neutrophils. The exact signaling of the priming pathway by GH has not been demonstrated. In this study, we investigated intracellular signaling of priming by recombinant human growth hormone (rGH) in human neutrophils. A low concentration of rGH (10-100 ng/ml) significantly enhanced the O2- production from neutrophils triggered with N-formyl-1-methionyl-1-leucyl-1-phenylalanine in a dose-dependent manner. Recombinant GH directly increased the fluorescence intensity of intracellular Ca2+ labeled with fluo 3-AM in neutrophils. The change of fluorescence intensity of cytosolic Ca2+ was dependent on the rGH concentration. The peak level of fluorescence intensity was observed at 3 to 5 min after treatment with rGH. The priming effect of rGH on O2- production via Ca2+ was abrogated by Ca2+ channel blockers such as dentrolene and verapamil. Furthermore, preincubation with genistein, a tyrosine kinase inhibitor, blocked the rGH-induced increases in Ca2+ and O2- production. This finding suggests that GH can act through the increase of intracellular Ca2+ as a priming agent to activate neutrophils for an enhanced respiratory burst.

Adult↗
PubMed1997

Changes in alpha wave and state anxiety during ChunDoSunBup Qi-training in trainees with open eyes.

We investigated the effects of ChunDoSunBup (CDSB) Qi-training, one of the Korean popular Qi-training systems, on EEG patterns, activation coefficients and state anxiety in 13 trainees with open eyes. CDSB Qi-training procedure consists of 3 stages: sound exercise, reciting Chunmoon, which is similar to a mantra; haeng-gong, a kind of body motion; and mediation. Compared to the control state (resting state before Qi-training), subjects reported less state anxiety, their activation coefficients decreased significantly during sound exercise and meditation in the occipital regions. Mean relative power and changes of mean absolute power of alpha wave increased significantly during sound exercise and meditation in the occipital regions. These results suggest that sound exercise and meditation in ChunDoSunBup Qi-training may reduce activation of the visual cortex and influence the thalamus and other functions of the brain. These could reduce anxiety levels and modulate the psychological, neurological, and physiological functions in man.

Adult↗
PubMed1997

Visual evoked potential guidance for posteroventral pallidotomy in Parkinson's disease.

Visual evoked potentials (VEPs) to photic stimulation of the eyes were used to identify the optic tract and thus determine the location of the globus pallidus internus (GPi) in eight patients with Parkinson's disease who then underwent posteroventral pallidotomy. Distinct waves appeared at 1 or 2 mm below the target (4 to 5 mm below the intercommissural line) and the amplitude significantly increased at 5 or 6 mm below, strongly suggesting that the electrode was in contact with the optic tract. In the medio-lateral direction, potentials were successively recorded in an area of 4 to 8 mm length, indicating the width of the optic tract. The trajectory at the mid point showed the most significant potentials which suggested the center of the optic tract. The site of the first lesion was placed 0 to 2 mm lateral to this trajectory and 5 mm above the point at which the amplitudes of responses increased. The actual lesion site significantly differed from the tentative target in a medio-lateral direction by 1 to 5 mm (mean 3.0 +/- 1.5 mm, n = 6). The Unified Parkinson's Disease Rating Scale score significantly improved and magnetic resonance imaging taken 2 or 3 weeks after the operation showed a lesion within the GPi in each patient. Recording of VEPs greatly facilitates accurate determination of the GPi.

Aged↗
PubMed1997

Epidermoid tumor in the sphenoid sinus--case report.

A 36-year-old male presented with a very rare epidermoid tumor in the sphenoid sinus manifesting as paresis of the right sixth cranial nerve and diplopia. Computed tomography and magnetic resonance imaging revealed a mass lesion in the sphenoid sinus expanding to the clivus. The cystic tumor, which contained cholesterin crystals, was extensively removed via the transsphenoidal approach. Histological examination showed epidermoid cell layers, consistent with the diagnosis of epidermoid tumor. Epidermoid tumors should be considered in the differential diagnosis of lesions in the sphenoid sinus.

Adult↗
PubMed1997

Selective cochlear neurotomy in the cerebellopontine cistern using electrophysiological monitoring in a patient with intractable tinnitus. Case report.

Selective cochlear neurotomy for intractable tinnitus is quite difficult to perform because there is no way to approach the cochlear nerve without interfering with other neural structures. The authors successfully performed selective cochlear neurotomy in the cerebellopontine cistern in a patient with persistent intractable high-pitched tinnitus, but with normal hearing and vestibular functions, by monitoring cochlear nerve compound action potentials and auditory brainstem responses. The procedure is a very simple and safe technique for the treatment of intractable tinnitus. Although this destructive procedure is the last choice of treatment, it can be justified in patients who have poor hearing and severe tinnitus in spite of normal vestibular functions. The procedure may also be applied in some rare cases such as that of the present patient whose quality of life was markedly reduced because loud tinnitus prevented him from hearing anything with the affected ear even though his hearing and vestibular functions were normal.

Action Potentials↗
PubMed1996

Comparison of the kidney dose between supine and prone position for pelvic and periaortic irradiation.

We compared the doses received by the kidney in supine and prone positions for pelvic and periaortic irradiation. Kidney locations were verified by CT images taken with patients in the same position as during the treatment. Due to the shift of the kidney anteriorly during prone position, treatment in supine position delivered a much lower dose to most of the kidney than treatment in the prone position. Therefore, for periaortic irradiation treatment, the supine position should be considered to minimize the dose to the kidneys, even though the prone position with a belly board can reduce the dose to the small bowel.

Humans↗
PubMed1996

Preoperative diagnosis of intratemporal facial nerve tumor: high-resolution CT and otoscopic findings in 4 cases.

Four cases of facial nerve tumor were treated in our clinic during the past 16 years, one of which was a recurrence 12 years after the resection. Another case presented with relapsing facial palsy of sudden onset. The others presented with slowly progressive facial palsy. In each of the four cases, the horizontal and vertical portions were included in the tumor extension, and a mass was revealed in the posterior tympanic cavity by use of otoscopy. High-resolution CT, performed in all but the earliest case, proved to be the most valuable diagnostic tool, indicating the anatomical correlation of the tumor with the facial canal. With the diagnosis preoperatively established, facial reanimation procedure could be applied immediately after the tumor resection except in the recurrent case.

Cranial Nerve Neoplasms↗
PubMed1996

Surgical approach to the internal auditory meatus in acoustic neuroma surgery: significance of preoperative high-resolution computed tomography.

OBJECTIVE AND METHOD: To establish a surgical approach that provides better access to the internal auditory meatus (IAM) in acoustic tumor removal via a suboccipital transmeatal route, the anatomic location of the labyrinth with regard to the sigmoid-fundus line and the extent of bone removal from the IAM were evaluated by pre- and postoperative high-resolution computed tomography for 47 patients. RESULTS: The labyrinth was located lateral to the sigmoid-fundus line in 22 cases (lateral type, 46.8%), on the line in 9 (on-the-line type, 19.1%), and medial to the line in 16 (medial type, 34.0%). Postoperative high-resolution computed tomography showed that the mean length of the posterior wall from the fundus was shortened to 5.1 +/- 1.1 mm (n = 27) in the partially resected group and to 2.0 +/- 0.6 mm (n = 20) in the widely opened IAM group. The labyrinth was damaged in four cases from the widely opened IAM group; the preoperative status of the labyrinth was medial to the sigmoid-fundus line in three and on the line in one. The cochlear nerve was preserved in seven (31%) partially resected and in eight (50%) widely opened IAM cases. The overall success rate of hearing preservation was 4 of 22 (18.2%) partially resected and 5 of 16 (31.2%) widely opened cases. CONCLUSION: Preoperative evaluation of the anatomic relation between the IAM and the labyrinth by high-resolution computed tomography provides an efficient surgical approach to the IAM and contributes to anatomic and functional preservation of the cochlear nerve.

Female↗
PubMed1996

Myelopathy caused by retro-odontoid disc hernia: case report.

OBJECTIVE AND IMPORTANCE: Among masses in the craniovertebral junction causing severe compression of the medulla and upper cervical cord, cases of retro-odontoid disc hernia are extremely rare. We report a case of retro-odontoid disc hernia resulting in severe myelopathy. CLINICAL PRESENTATION: An 82-year-old man suffered from progressive tetraparesis. Although cervical radiological studies showed marked spondylotic change, no congenital malformations or traumatic lesions were identified. Magnetic resonance imaging disclosed a retro-odontoid soft tissue mass with peripheral enhancement compressing the medulla and the upper cervical cord posteriorly. INTERVENTION: The patient underwent surgery through the posterior approach. The histopathological examination of the surgical specimen revealed fibrocartilage accompanied by reactive vascular tissue; the mass was diagnosed as a retro-odontoid disc hernia. CONCLUSION: In the differential diagnosis of mass lesions compressing the neural structures in the craniovertebral junction, retro-odontoid disc hernia, although extremely rare, should be considered to be one possibility. The posterior approach with wide laminectomies provides a good operative field from which to remove the retro-odontoid mass and is especially adequate for elderly patients, because it is less invasive than other procedures.

Aged↗
PubMed1996

Acute effect of qigong training on stress hormonal levels in man.

We observed the acute effects of Qigong training on the levels of human endogenous opioid peptides, such as beta-endorphin, and other stress hormones [adrenocorticotrophic hormone (ACTH), cortisol, and dehydroepiandrosterone-sulfate (DHEA-S)] in a group of ChunDoSunBup Qigong trainees. At pre (-10 min), mid (40 min) and post (70 min) time of training, blood was taken for the determination of plasma level of hormones. The level of beta-endorphin was significantly increased during the mid-time of training while the level of ACTH declined at the mid- and post-time of training. Cortisol and DHEA-S were not significantly changed during training. This result suggests that Qigong training, as a stress coping method, affects and plays a role in hormonal regulation related to the maintenance of homeostasis in man.

Adrenocorticotropic Hormone↗
PubMed1995

Effect of qigong training on proportions of T lymphocyte subsets in human peripheral blood.

The effect of Qigong training on proportions of T lymphocyte subsets was investigated in human peripheral blood. We observed that the ratio of CD4+/CD8+ T lymphocytes was increased as much as 50% in a trainee group who practiced Qigong training more than 5 months compared to a normal healthy group who did not practice. The absolute number of CD4+ T lymphocytes was also elevated in trainee group with 100 cells/mm3 more than in normal healthy group. The positive correlation between the ratio of CD4+/CD8+ T lymphocytes and the ratio of CD4+45RA-/CD4+CD45RA+ T lymphocytes was shown in the trainee group. In contrast, there was a negative correlation between the ratio of CD4+/CD8+ T lymphocytes and the ratio of CD8+CD57+/CD8+CD57- T lymphocytes in the trainee group. The data indicate that Qigong training affects the profile of lymphocyte subsets in human peripheral blood, especially the proportion of CD4+ T lymphocytes.

Adult↗
PubMed1995

Delayed cutaneous hypersensitivity reactions in Qigong (chun do sun bup) trainees by multitest cell mediated immunity.

To determine the difference of cellular immunity between a Qigong trainee group and a normal healthy group, skin tests for delayed cutaneous hypersensitivity (DCH) were carried out with ubiquitous seven antigens. The maximal antigen response time was faster in Qigong trainee group (24 hr) and the response antigen number was also higher in the Qigong trainee group (6 antigens) than in normal healthy person (48 hr and 4 antigens). Qigong trainee also had a larger induration diameter (5.14 mm) than normal healthy person (3.79 mm) at 24 hr. Our results represent the difference in cell mediated immunity (CMI) between Qigong trainees and normal healthy subjects.

Adult↗
PubMed1995

Chronological changes of arterial diameter, cGMP, and protein kinase C in the development of vasospasm.

BACKGROUND AND PURPOSE: We hypothesized that nitric oxide exerts a negative feedback control on protein kinase C (PKC) activation, and the disturbance of the feedback control after subarachnoid hemorrhage results in vasospasm due to PKC activation. This study was undertaken to verify this hypothesis. METHODS: Different dogs were prepared for three separate experiments: measurement of the angiographic diameter of the basilar artery and determination of cGMP and PKC activity in vascular smooth muscle cells. In each experiment, two models were used: the single-hemorrhage model for mild vasospasm and the two-hemorrhage model for severe vasospasm. In both models, chronological changes of these three parameters were examined from day 1 until day 7. RESULTS: In the single-hemorrhage model, mild vasospasm and a slight decrease of the cGMP level were noted on day 4, then both returned to the baseline levels on day 7. PKC activity was slightly enhanced throughout the study period. In the two-hemorrhage model, severe vasospasm and a significant decrease of the cGMP level were observed on day 5 and persisted until day 7. PKC activity was remarkably enhanced from day 5 until day 7. The differences between the two models with regard to the three parameters were statistically significant. CONCLUSIONS: The decrease of cGMP level and the enhancement of PKC activity were obviously associated with the development of severe vasospasm. We conclude that subarachnoid hemorrhage disturbed the feedback control exerted by nitric oxide on PKC activation, leading to PKC-dependent vasospasm.

Animals↗
PubMed1994

Atrial natriuretic peptide immunoreactivity in the eggs of the silkworm Bombyx mori.

Synthesis and secretion of atrial natriuretic peptides (ANPs) are not confined to the atrium, but are also present in other tissues. Recently, we have found synthesis of ANP in the eggs of several vertebrate animals. The present study was undertaken to determine whether immunoreactive ANP (irANP) is present in the egg of an invertebrate, the silkworm (Bombyx mori L.). The serial dilution curve of egg extracts of silkworm was parallel to the standard curve of atriopeptin III. Analysis of ANP immunoreactivity by gel filtration chromatography and reverse-phase HPLC showed that the major immunoreactivity corresponded to rat proANP. The semipurified irANP of egg extracts produced a dose-dependent relaxation on rat aortic strips, which was blocked by preincubation with anti-ANP antiserum. Therefore, we suggest that ANP is synthesized in the silkworm egg.

Animals↗
PubMed1994

Subarachnoidal abscess associated with bacterial meningitis in infants--two case reports.

Two infants, an 11-month-old boy and a 7-month-old girl, presented with subarachnoidal abscess associated with severe bacterial meningitis refractory to intensive managements with antibiotics. Computed tomography (CT) revealed bifrontal extracerebral low-density areas and remarkably enhanced surfaces of the bilateral frontal lobes postcontrast. Surgical exploration disclosed thick pus accumulation in the subarachnoid space which required curettage. The boy developed appropriately for his age, but the girl showed severe psychomotor retardation because of additional complications such as subdural fluid collection and hydrocephalus associated with the subarachnoidal abscess. Appropriate early neurosurgical management of subarachnoidal abscess is essential for satisfactory psychomotor development. Postcontrast CT should be performed to detect the subarachnoidal abscess as early as possible, and extensive craniotomy to remove the subarachnoidal pus accumulation performed to preserve psychomotor development.

Brain Abscess↗
PubMed1993

Immunoreactive atrial natriuretic peptides in the oocyte.

1. The presence and partial characterization of immunoreactive ANP (irANP) in eggs were investigated using high performance liquid chromatography (HPLC), immunohistochemistry and Northern-blot hybridization in mammalian and nonmammalian vertebrates. 2. Serial dilution curves of egg extracts from frogs and freshwater teleostean fishes (silver crusian carp and loach) were parallel to the standard curve of atriopeptin III. Rat oocytes also contained irANP (25-30 pg/egg). 3. The HPLC profile of irANP showed two main peaks corresponding to low and high molecular weight of irANP. 4. ANP mRNA was detected in the fish eggs. With immunohistochemical analysis of the rat ovarian follicles, this ANP-like material was localized mainly at the oocytes. 5. We, therefore, suggest that the vertebrate oocytes synthesize ANP and that the presence of ANP in the oocytes may be linked with the cell differentiation.

Animals↗