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Biomedical subjects

S J Oh

Publications and source records attributed to S J Oh.

At least 37 records · Page 2Linked to original sources
PubMed2001

Light- and electron-microscopic analysis of neuropeptide Y-immunoreactive amacrine cells in the guinea pig retina.

We investigated the morphology and synaptic connections of neuropeptide Y (NPY)-containing neurons in the guinea pig retina by immunocytochemistry, using antisera against NPY. Specific NPY immunoreactivity was localized to a population of wide-field and regularly spaced amacrine cells with processes ramifying mainly in stratum 1 of the inner plexiform layer (IPL). Double-label immunohistochemistry demonstrated that all NPY-immunoreactive cells possessed glutamic acid decarboxylase 65 immunoreactivity. The synaptic connectivity of NPY-immunoreactive amacrine cells was identified in the IPL by electron microscopy. The NPY-labeled amacrine cell processes received synaptic input from other amacrine cell processes and bipolar cell axon terminals in stratum 1 of the IPL. The most frequent postsynaptic targets of NPY-immunoreactive amacrine cells were other amacrine cell processes. Synaptic outputs to bipolar cells were also observed in a small number of cases. This finding suggests that NPY-containing amacrine cells may influence inner retinal circuitry in stratum 1 of the IPL, thus mediating visual processing.

Amacrine Cells↗
PubMed2001

Up-regulated eNOS protects blood-retinal barrier in the L-arginine treated ischemic rat retina.

Using immunoblot analysis and immunocytochemistry, we investigated expression and cellular localization of endothelial nitric oxide synthase (eNOS) and proliferating cell nuclear antigen (PCNA) in the l-arginine treated ischemic rat retina. In parallel, we tested whether the blood-retinal barrier was intact by immunocytochemistry using an antiserum against IgG. In the l-arginine-treated ischemic retina, the magnitude of the increased eNOS was higher, and PCNA was expressed in endothelial cells as well as in neurons in the inner retina during the whole experimental period. Finally, IgG leakage was not detectable in the l-arginine-treated ischemic retina. Our results clearly suggest that the increased NO production by eNOS may be essential for the survival of endothelial cells in the rat retina following transient ischemia.

Animals↗
PubMed2001

The expression and cellular localization of phospholipase D1 in the rodent retina.

Phospholipase D (PLD) is one of the intracellular signal transduction enzymes and plays an important role in a variety of cellular functions. We investigated the expression and cellular localization of the PLD isozyme PLD1 in the rodent retina. Western blot analysis showed the presence of PLD1 at the protein level in the rat, mouse and guinea pig retinas. PLD1 immunoreactivity was localized in all Müller cells. Thus, PLD1 protein appears to be important in the functions of these cells in the rodent retina.

Animals↗
PubMed2001

Large-fiber neuropathy in distal sensory neuropathy with normal routine nerve conduction.

Near-nerve needle sensory nerve conduction of plantar nerves in 100 patients with distal sensory neuropathy with normal routine nerve conduction (DSN-NNC) found the definite neuropathy pattern (abnormality in more than three of six tested nerves) in 65%, axonal neuropathy in 35%, and the known cause in 37% of patients. Absent or diminished reflexes were a reliable indicator for large fiber neuropathy (LFN). This near-nerve needle plantar nerve study provides useful and unequivocal evidence of its value in identifying neuropathy in DSN-NNC by finding LFN in 65% of patients.

Action Potentials↗
PubMed2001

Conjunctival cul-de-sac reconstruction with radial forearm free flap in anophthalmic orbit syndrome.

Contracted eye socket is a constant cosmetic embarrassment to the patient. It not only renders patients unable to maintain an eye prosthesis, but it becomes a source of chronic discharge and irritation. Eye socket reconstruction with free skin, mucous membrane, cartilage, or dermis-fat usually remains unsatisfactory in many cases, due to secondary graft contracture. Traumatic injuries to the orbit and neighboring soft tissue frequently lead to a contracted eye socket. This condition results from the need for removal of the traumatized conjunctiva at the time of the enucleation, along with the traumatized eyeball, for satisfactory wound closure. In traumatic anophthalmos patients, a radial forearm free flap was used for conjunctival cul-de-sac reconstruction. Eye socket beds were developed as hinge-shaped flaps and used as lining for the upper and lower palpebrae. The authors conclude that the radial forearm flap is a useful alternative in the treatment of traumatic anophthalmos.

Adult↗
PubMed2001

Direct local approach through a W-shaped incision in moderate or severe blowout fractures of the medial orbital wall.

For moderate or severe blowout fractures of the medial orbital wall, the goals of treatment are complete reduction of the herniated soft tissue and anatomic reconstruction of the wall without surgical complications. Various surgical approaches have been used, depending on the anatomic location and the extent of medial wall fracture. However, there is no consistent method to achieve the treatment goals with minimal morbidity because of one or more problems of limitation of entire medial wall exposure, limitation of large implant or bone graft insertion, surgical damage of important periorbital or intraorbital structures, or postoperative scar deformities. In this study, a direct local approach through a 3-cm, W-shaped incision on the superior medial orbital area was used as a consistent method to reconstruct medial orbital blowout fractures. The angle of the W-limbs is 110 to 120 degrees. Four limbs of the W were placed parallel or oblique to the relaxed skin tension lines. This technique was applied to 39 orbits of 37 patients with moderate or severe blowout fractures of the medial orbital wall. This approach provided exposure of the entire medial orbital wall, adequate placement of a large implant, short operation time within 2 hours, and no damage of important internal structures. Postoperative computed tomographic scans showed complete reduction of the herniated orbital tissues and anatomic reconstruction of the medial orbital wall without complication related to the surgical approach in all cases. During the follow-up period of 6 to 14 months, excellent functional and cosmetic results were observed with an inconspicuous scar without secondary scar deformities. Therefore, a direct local approach through a W-shaped incision on the superior medial orbit may be a consistent method to gain the surgical goal in treatment of moderate or severe blowout fractures of the medial orbital wall.

Adolescent↗
PubMed2001

Sensory Guillain-Barré syndrome.

OBJECTIVE: To report eight cases of sensory Guillain-Barré syndrome (GBS). BACKGROUND: The concept of sensory equivalent to ascending paralysis of GBS was raised in 1958, and the diagnostic criteria for a sensory loss and areflexia variant of GBS were proposed in 1981. However, clinical cases meeting these criteria have been relatively scarce. METHODS: During a 13-year period between 1986 and 1999, the authors collected eight cases of an acute sensory demyelinating neuropathy that met most of the proposed diagnostic criteria of a sensory variant of GBS. RESULTS: In all patients, sensory neuropathy was sudden at onset and peaked to maximal deficit within 4 weeks. In five (63%) cases, there was an antecedent viral illness. All patients had objective sensory loss and diminished or absent reflexes. None showed any muscle weakness. In all four patients in whom the spinal fluid was examined during the first 4 weeks, there was albuminocytologic dissociation. All of the patients had electrophysiologic evidence of demyelination in at least two nerves. Demyelination was demonstrated in motor nerve conduction in seven patients and in sensory nerve conduction in one, indicating that motor nerve conduction studies were the key for the diagnosis of demyelinating neuropathy. All patients had sensory nerve conduction abnormalities in at least one nerve. Three patients responded to immunotherapies. All had a favorable outcome, with a monophasic course of disease and no sign of relapse. CONCLUSION: The current study confirms the existence of sensory GBS.

Adult↗
PubMed2001

Intravascular ultrasound analysis of beta radiation therapy for diffuse in-stent restenosis to inhibit intimal hyperplasia.

We evaluated the efficacy of beta-radiation therapy ((188)Re-MAG(3)) to inhibit intimal hyperplasia (IH) in diffuse in-stent restenosis by intravascular ultrasound (IVUS) analysis in 50 patients. Nine patients who did not agree with radiation therapy, and therefore underwent rotational atherectomy and balloon angioplasty for diffuse in-stent restenosis in the same study period, were selected for control groups. Serial IVUS comparisons were available in 44 of 50 patients with radiation therapy and 7 of 9 control patients. At 6-month follow-up, there was less significant increase of IH area in patients with radiation therapy than in control patients (Delta IH area = 0.1 +/- 0.8 mm(2) vs. 2.6 +/- 1.8 mm(2), P > 0.001 in mean values, and 0.6 +/- 1.4 mm(2) vs. 2.9 +/- 2.1 mm(2), P = 0.026 in values of follow-up lesion site, respectively). In conclusion, beta-radiation therapy might be an effective treatment modality to inhibit intimal hyperplasia in patients with diffuse in-stent restenosis.

Aged↗
PubMed2001

Distal sensory nerve conduction of the superficial peroneal nerve: new method and its clinical application.

The superficial peroneal nerve subserves sensation on the entire surface of the dorsum of the foot, except in small areas. All previously reported techniques for evaluating nerve conduction along this nerve tested a proximal portion of the nerve. We report a new method for evaluating sensory nerve conduction of the four branches of the distal superficial peroneal nerve. Two branches to the second and third toes of the medial dorsal cutaneous nerve and two branches to the fourth and fifth toes of the intermediate dorsal cutaneous nerve were studied orthodromically and antidromically in 37 feet of 21 normal volunteers using surface stimulating and recording electrodes and with a distance of 10 cm between the stimulating and recording electrodes. Maximum nerve conduction velocities (NCV) ranged from 41.8 to 46.9 m/s, and mean response amplitude ranged from 6.5 to 7.6 microV with the orthodromic technique. Values for NCV were almost identical when elicited by antidromic and orthodromic techniques, but response amplitudes were higher with the antidromic technique. Mean amplitudes of the distal superficial peroneal nerve were about 50% of the proximal superficial peroneal, and the conduction velocity in the distal superficial peroneal was slower than that in the proximal superficial peroneal nerve, by 8-14 m/s. In seven cases, distal superficial peroneal neuropathy was confirmed with this technique: two with proper digital neuropathy, two with medial dorsal cutaneous neuropathy, and three with intermediate dorsal cutaneous neuropathy.

Adult↗
PubMed2001

Reorganization of horizontal cell processes in the developing FVB/N mouse retina.

We investigated the morphological changes of horizontal cells after postnatal photoreceptor degeneration in the developing FVB/N mouse retina, using immunocytochemistry with anti-calbindin D-28K. From postnatal day 14 (P14) onwards, processes emerging from horizontal cells descend into the inner plexiform layer (IPL) and ramify mainly in stratum 1 of the IPL. Electron microscopy revealed that the descending processes make synaptic contacts with bipolar cells in the outer plexiform layer. Our results clearly demonstrate that loss of photoreceptor cells induces the reorganization of horizontal cell processes in the retinas of FVB/N mice as they mature.

Animals↗
PubMed2001

Supranormal differential renal function is real but may be pathological: assessment by 99m technetium mercaptoacetyltriglycine renal scan of congenital unilateral hydronephrosis.

PURPOSE: It is unclear whether supranormal differential renal function of the hydronephrotic kidney is real or artifactual. We investigated the effect of clinical and renographic parameters on differential renal function. MATERIALS AND METHODS: The study included 34 males and 10 females from 1 to 9 months old (median age 2.6 months) with unilateral congenital hydronephrosis. A 99mtechnetium (Tc) mercaptoacetyltriglycine (MAG3) scan was performed, and regions of interest were drawn on the kidneys, and perirenal and lateral backgrounds. Differential renal function was calculated with and without background subtraction at 30-second intervals from 0.5 to 3 minutes after injection of 99mTc-MAG3. The effects of age, sex, obstruction, site and size of the hydronephrotic kidney were analyzed using the generalized estimating equations method. RESULTS: There were 11 right and 33 left hydronephrotic kidneys. An obstructive renographic pattern was present in 33 cases. The trends of differential renal function according to intervals were different between kidneys with and without background subtraction, and differential renal function increased significantly as size increased (p <0.05). Differential renal function of the hydronephrotic kidney with an obstructive renographic pattern increased with time when perirenal or no background subtraction was applied (p <0.05). The effects of age, sex or laterality on differential renal function were not significant. Supranormal function (differential renal function 55% or greater) was present regardless of background subtraction methods and measurement time. CONCLUSIONS: Differential renal function is higher in larger hydronephrotic kidney but function of the kidney with an obstructive pattern is overestimated on later phases of 99mTc-MAG3 renal scan. Supranormal differential renal function is real and may be pathologic since it is prone to occur in larger obstructive hydronephrotic kidneys.

Diuretics↗
PubMed2001

Decrease in carotid intima media thickness after 1 year of cilostazol treatment in patients with type 2 diabetes mellitus.

A multicenter exploratory study at three university hospitals was performed to evaluate the effect of oral cilostazol on intima media thickness (IMT) in diabetic patients. A total of 141 patients was recruited in this study and randomized into a cilostazol group and a placebo (control) group. One hundred and twenty patients completed the study (i.e. 60 on cilostazol and 60 on placebo). Biochemical profiles and the IMT of the common carotid artery (CCA) determined by high-resolution B-mode ultrasonography were measured at 0, 6, and 12 months after the oral administration of 100--200 mg of cilostazol or placebo (i.e. two or four times daily for 12 months). Clinical and biochemical characteristics, the treatment modality, and microvascular diabetic complications after randomization were not significantly different between the two groups after the study. In the cilostazol treatment group, left CCA average IMT significantly decreased from 0.94+/-0.03 to 0.91+/-0.02 mm at 6 months (P<0.05), and thereafter increased to 0.92+/-0.01 mm (P>0.05) at 12 months, whereas in the control group, it increased from 0.92+/-0.03 to 0.93+/-0.01 mm at 6 months (P>0.05), and to 0.94+/-0.01 mm at 12 months (P>0.05). As for the right CCA average IMT, it decreased from 0.83+/-0.03 to 0.82+/-0.01 mm at 6 months (P<0.05), and to 0.81+/-0.01 mm at 12 months (P<0.05) in the cilostazol group, whereas it increased from 0.87+/-0.03 to 0.89+/-0.01 mm at 6 months (P<0.05), and to 0.90+/-0.01 mm at 12 months (P<0.05) in the control group (P<0.05). After correction for risk factors such as blood pressure, smoking, and lipid profiles, there were significant changes in left and right CCA average IMT for both groups (P<0.05). Left and right CCA average IMT was significantly different between the two groups (P<0.05). After making statistical corrections for blood pressure, smoking, and lipid profiles, the differences between these two groups remained significant (P<0.05). Meanwhile, there were no differences between the groups in the change of risk factors such as BMI, blood pressure, blood sugar, HbA(1c), and lipid profiles. Generally, cilostazol was well tolerated and the most common side effect in the cilostazol group was headache (12/60), mostly early in the treatment regimen. The results suggest that oral cilostazol may be helpful in the treatment of atherosclerosis in type 2 diabetic patients, although conventional cardiovascular risk factors remained unmodified.

Blood Glucose↗
PubMed2001

Treatment of diffuse in-stent restenosis with rotational atherectomy followed by radiation therapy with a rhenium-188-mercaptoacetyltriglycine-filled balloon.

OBJECTIVES: This study was done to evaluate the feasibility and efficacy of beta-radiation therapy with a rhenium-188-mercaptoacetyltriglycine ((188)Re-MAG(3))-filled balloon after rotational atherectomy for diffuse in-stent restenosis (ISR). BACKGROUND: Rotational atherectomy has been shown to be safe and efficient for the treatment of ISR, but the recurrence rate is still high. Intracoronary beta-irradiation after rotational atherectomy may be a reasonable approach to prevent recurrent ISR. METHODS: Fifty consecutive patients with diffuse ISR (length >10 mm) in native coronary arteries underwent rotational atherectomy and adjunctive balloon angioplasty, followed by beta-irradiation using a (188)Re-MAG(3)-filled balloon catheter. The radiation dose was 15 Gy at a depth of 1.0 mm into the vessel wall. RESULTS: The mean lengths of the lesion and irradiated segment were 25.6 +/- 12.7 mm and 37.6 +/- 11.2 mm, respectively. Radiation was delivered successfully to all patients, with a mean irradiation time of 201.8 +/- 61.7 s. No adverse event, including myocardial infarction, death or stent thrombosis, occurred during the follow-up period (mean 10.3 +/- 3.7 months), and nontarget vessel revascularization was needed in one patient. The six-month binary angiographic restenosis rate was 10.4%, and the loss index was 0.17 +/- 0.31. CONCLUSIONS: Beta-irradiation using a (188)Re-MAG(3)-filled balloon after rotational atherectomy is safe and feasible in patients with diffuse ISR, and it may improve their clinical and angiographic outcomes. Further prospective, randomized trials are warranted to evaluate the synergistic effect of debulking and irradiation in patients with diffuse ISR.

Atherectomy, Coronary↗
PubMed2001

In vitro antimicrobial activity of a chitooligosaccharide mixture against Actinobacillus actinomycetemcomitans and Streptococcus mutans.

The purpose of this study was to evaluate the in vitro antibacterial activity of a chitooligosaccharide mixture (MW 2000-30000 Da) with a deacetylation degree of 91.5% against two representative oral pathogens, Actinobacillus actinomycetemcomitans and Streptococcus mutans. A 0.1% concentration of the chitooligosaccharides (derived from the exoskeletons of marine crustaceans) was used to estimate antibacterial activity. Approximately 2 logcolony forming units (CFU)/ml of A. actinomycetemcomitans were inactivated by 0.1% chitosan after 30 min, while 120 min exposure inactivated about 4.5 logCFU/ml of this organism. In contrast, the level of inactivation against S. mutans was less than 0.5 logCFU/ml after an exposure of up to 120 min. Electron microscopy showed that the exposure of A. actinomycetemcomitans to the chitooligosaccharides resulted in the disruption of cell membranes and that it could be considered for the treatment of periodontal diseases associated with A. actinomycetemcomitans.

Aggregatibacter actinomycetemcomitans↗
PubMed2001

Automation of the synthesis of highly concentrated 188Re-MAG3 for intracoronary radiation therapy.

We have developed an efficient method and an automated synthetic system for the preparation of highly concentrated 188Re-MAG3. Routine production of 188Re-MAG3 for use in intracoronary radiation therapy was performed by compressed air driven semi-automated shielded system. 188Re-MAG3 was prepared with a commercial kit and reducing agents, purified and concentrated by C18 Sep-Pak cartridges to desired radioactivity and volume. Using this automated system, reproducible radiolabeling yields of 80-85% were obtained.

Angioplasty, Balloon, Coronary↗
PubMed2001

Seasonal characteristics of haze observed by continuous visibility monitoring in the urban atmosphere of Kwangju, Korea.

Continuous visibility monitoring has been carried out in Kwangju, Korea since May 1999. The total light extinction coefficient bext measured by a transmissometer and reveals seasonal trends in urban visual air quality, especially under hazy conditions with a visual range of less than 15 km. Seasonal atmospheric visibility under low relative humidity during the winter was observed to be better than during any other seasons. Summertime visibility was severely degraded due to highly increased light scattering by hygroscopic particles under high humidity atmospheric conditions. Visibility during spring and fall was also moderate. However, yellow sand in spring caused the lowest visibility conditions over the measurement area for a few days. With continuous monitoring using the transmissometer, the daily average seasonal visual range was measured to be 13.1, 9.2, 11.0, and 13.9 km in spring, summer, fall and winter, respectively. Under the atmospheric humidity condition less than 60%, visual range was observed to be 16.1, 13.9, 15.1, and 16.6 km in spring, summer, fall, and winter, respectively. The mean light extinction budget by sulfate and nitrate aerosols was determined to be the highest value of 63.71% during the summer and the lowest value of 27.08% during spring. During the 'yellow sand dust' period, a mean light extinction budget by soil particles was estimated to be at an unusually high value of 44.22%.

Air Pollutants↗
PubMed2001

Neurolymphomatosis associated with muscle and cerebral involvement caused by natural killer cell lymphoma: a case report and review of literature.

We report a biopsy-proven case of neurolymphomatosis (NL) presenting with sensory motor axonal polyneuropathy, polymyositis, and cerebral involvement. Ours is the second reported case of NL caused by natural killer-cell lymphoma defined by morphology and immunophenotyping. For 3 months, the patient developed stocking-glove distribution of hypesthesia, subacute progressive weakness and mental deterioration. EMG showed severe sensorimotor mixed axonal-demyelinating polyradiculoneuropathy. Lumbar puncture revealed mildly high protein level with normal glucose and cell count. Sural nerve biopsy demonstrated lymphomatous axonal neuropathy and muscle biopsy was indicative of lymphomatous polymyositis. Brain MRI revealed multiple white matter lesions, consistent either with progressive multifocal leukoencephalopathy or cerebral lymphoma. Bone marrow biopsy showed neoplastic infiltrates. The patient died of multiple organ failure prior to initiation of chemotherapy.

Bone Marrow↗