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Biomedical subjects

S J Oh

Publications and source records attributed to S J Oh.

At least 91 records · Page 5Linked to original sources
PubMed1999

Immunocytochemical localization of nitric oxide synthase in the mammalian retina.

The localization of nitric oxide synthase (NOS) was investigated by immunocytochemistry and immunoblotting using an antiserum against neuronal NOS in the rat, mouse, guinea pig, rabbit and cat retinae. Western blot analysis of retinal tissue extracts showed that the NOS-immunoreactive band of 155 kDa was present in all species. In the rat, mouse, guinea pig and rabbit retinae, two types of amacrine cells and a class of displaced amacrine cells were consistently NOS-labeled. In the cat retina, unlike other mammals, one type of amacrine cells and two types of displaced amacrine cells showed NOS immunoreactivity. NOS immunoreactivity was further found in some bipolar cells of the rat and guinea pig, some interplexiform cells of the mouse, some photoreceptor cells of the rabbit and some Müller cells of the cat.

Animals↗
PubMed1999

New near-nerve needle nerve conduction technique: differentiating epicondylar from cubital tunnel ulnar neuropathy.

At the elbow, the ulnar nerve is compressed most commonly either in the epicondylar groove or at the cubital tunnel. While conventional electrodiagnosis may localize an ulnar neuropathy to the elbow, separating epicondylar syndrome (tardy ulnar nerve palsy) from cubital tunnel syndrome is more difficult. We describe a new method using a near-nerve needle technique for distinguishing these two types of ulnar neuropathy at the elbow. We placed three active needle electrodes across the elbow: the first was 4 cm above, and the second and third were 1.5 cm and 6 cm below the medial epicondyle, respectively. The latter two points were chosen because of the presence of the cubital tunnel in this segment. Sensory, motor, and mixed nerve conduction studies (NCS) were performed on these two segments (elbow segment and cubital tunnel segment) in 26 normal nerves and normal data were established. We also present 7 cases of epicondylar ulnar nerve palsy and 1 case of cubital tunnel syndrome in which we were able to confirm the diagnosis with the present method. In 3 cases of epicondylar ulnar nerve palsy, the present method accurately localized the lesion when other methods failed. We believe that this method will be helpful in distinguishing cubital tunnel syndrome from epicondylar ulnar nerve palsy, especially in early ulnar neuropathy in which only sensory fibers are involved.

Adult↗
PubMed1999

Lateral plantar neuropathy.

We report 8 cases of lateral plantar neuropathy (LPN). All had sensory impairment over the territory of the lateral plantar nerve. Near-nerve needle sensory nerve conduction study (NCS) of the plantar nerves showed abnormality confined to the lateral plantar nerve, confirming LPN. The most common cause for LPN was trauma and the most common site of injury was at the passage of the lateral plantar nerve through the abductor tunnel at the instep of the foot.

Action Potentials↗
PubMed1999

Morphology and synaptic connectivity of nitric oxide synthase-immunoreactive neurons in the guinea pig retina.

Immunocytochemical methods with an antiserum against neuronal nitric oxide synthase (NOS) were applied to identify the morphology and synaptic connectivity of NOS-like immunoreactive neurons in the guinea pig retina. In the present study, two types of amacrine cells were labeled with anti-NOS antisera. Type 1 cells had large somata located in the inner nuclear layer (INL) with long, sparsely branched processes ramifying mainly in stratum 3 of the inner plexiform layer (IPL). The somata of type 2 cells (smaller diameters) were located in the INL. Some displaced amacrine cells in the ganglion cell layer were labeled. The soma size of the displaced amacrine cells was similar to that of the type 2 amacrine cells. However, processes originating from type 2 amacrine cells and displaced amacrine cells stratified mainly in strata 1 and 5, respectively. Some cone bipolar cells were weakly NOS-immunoreactive. The synaptic connectivity of NOS-like immunoreactive amacrine cells was identified in the IPL by electron microscopy. NOS-labeled amacrine cell processes received synaptic input from other amacrine cell processes and bipolar cell axon terminals in all strata of the IPL. The most frequent postsynaptic targets of NOS-immunoreactive amacrine cells were other amacrine cell processes. Cone bipolar cells were postsynaptic to NOS-labeled amacrine cells in all strata of the IPL. Labeled amacrine cells synapsing onto ganglion cells were found only in sublamina b. A few synaptic contacts were observed between labeled cell processes. In the outer plexiform layer, dendrites of labeled bipolar cells made basal contact with cone pedicles or formed a synaptic triad opposed to a synaptic ribbon of cone pedicles.

Animals↗
PubMed1999

Immunocytological localization of dopamine in the guinea pig retina.

We examined dopaminergic neurons in the guinea pig retina; antisera against tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH), phenylethanolamine N-methyltransferase (PNMT) and an antiserum against gamma-aminobutyric acid (GABA) were used. In the present study, two types of amacrine cells were labeled with an anti-TH antiserum. However, no DBH and PNMT immunoreactivities were seen. The type 1 cell had a larger-sized soma located in the inner nuclear layer with processes ramifying mainly in stratum 1 of the inner plexiform layer (IPL). The type 2 cell had a smaller-sized soma and processes branching in stratum 3 of the IPL. The mean densities were 56.4 +/- 11.5/mm2 for the type 1 cell and 166.6 +/- 30.3/mm2 for the type 2 cell. Double immunocytochemistry using an antiserum against GABA revealed that while none of the type 1 cells showed GABA immunoreactivity, all of the type 2 cells displayed GABA immunoreactivity. Our results suggest that, in the guinea pig retina, the type 1 amacrine cells are pure dopaminergic and the type 2 cells are dopaminergic elements that use GABA as their second transmitter.

Age Factors↗
PubMed1999

No further development of renal scarring after antireflux surgery in children with primary vesicoureteral reflux: review of the results of 99mtechnetium dimercapto-succinic acid renal scan.

PURPOSE: Reports of previous studies using excretory urography indicate that significant numbers of new scars developed in 5 to 31% of cases and scarring progressed in 11 to 16% after antireflux surgery. We evaluated renal scarring after surgery using a more accurate method, that is dimercapto-succinic acid renal scintigraphy. MATERIALS AND METHODS: Between 1985 and 1997 antireflux surgery was performed for primary vesicoureteral reflux in 223 children at our hospital. Of these patients 45 boys and 29 girls with a median age of 74 months at surgery in whom preoperative and postoperative renal scans were available form the basis of our retrospective study. Renal scan was performed 0.3 to 58 months (median 2) preoperatively and 5.3 to 44 months (median 18.7) postoperatively. A total of 24 children (39 renal units) were followed further by additional scanning for as long as 25 to 120 months (median 43.2) postoperatively. Each scan was blindly reviewed for the size, number and zone location of cortical defects based on morphology. Interval changes were grouped into categories as improved, no change, progressed and new scar formation. RESULTS: Postoperatively there was no ureteral obstruction. Pyelonephritis developed in 2 patients (2.7%) and asymptomatic bacteriuria was noted in 35 (47.3%) postoperatively. Of the renal units 110 (86.6%) showed no change, while 15 (11.8%) were improved and 2 (1.6%) had progression. In no case was new renal scar formation observed. CONCLUSIONS: Contrary to most previous reports involving excretory urography, our results indicate no significant progression of renal scarring after antireflux surgery. In most cases postoperative followup renal scans demonstrated no significant morphological change. When there was change, it mostly involved the disappearance or decrease of renal scars.

Child↗
PubMed1999

Explosive burns during abusive inhalation of butane gas.

Explosion burns during abusive inhalation of butane gas rarely occurred in the past, but recently it has become a social problem among groups of teenagers. This cause constitutes 1.6% of admissions due to flame burn at the burn unit of Hallym Medical Center. A retrospective review during a five-year period identified 48 patients. The male to female ratio was 3:1. The mean age of patients was 16 years and 8 months. The places where the accidents occurred were commonly bedrooms or motel rooms. There were nine group settings of 27 patients at the time of the accident. Inhalation injury (n = 12) was noted on admission. The average burn size was 28.5 percent of the total body surface area. All patients sustained burn injury on the face, arms and hands and 24 patients among them had extended burn areas on the trunk and/or lower extremity. 22 patients (mean hospital stay; 51.6 d) required skin grafting and 12 patients (mean hospital stay; 22.3 d) were treated with conservative management. The mortality rate was 10.4 percent. Explosion burns during abusive inhalation of butane gas can result in mortality as well as major burn injuries.

Accidents↗
PubMed1999

Entrapment neuropathies of the tibial (posterior tibial) nerve.

Entrapment neuropathies of the tibial nerve are relatively rare. They are often misdiagnosed largely because of the clinician's low index of suspicion. The clinical features, diagnostic studies, and treatment of these disorders are reviewed in detail in this article. Almost all of these disorders can now be confirmed through nerve conduction and other image studies.

Decompression, Surgical↗
PubMed1999

Carbachol-induced sustained tonic contraction of rat detrusor muscle.

OBJECTIVE: To investigate the underlying contractile mechanism of the sustained tonic contraction (SuTC) induced by repetitive carbachol application in rat detrusor muscles. MATERIALS AND METHODS: Longitudinal muscle strips with no mucosa were obtained from the anterior wall of the urinary bladder in 12-week-old Sprague-Dawley rats. Carbachol (5 micromol/L) was applied repetitively to induce SuTC. The carbachol-induced SuTC was assessed in the presence of various Ca2+-channel blockers and drugs affecting intracellular Ca2+ concentration. RESULTS: The first application of carbachol elicited a large phasic contraction followed by a tonic contraction (TC); the carbachol-induced contraction was completely reversed by washing out the solution. However, the initial phasic contraction was not reproduced after a second or further application of carbachol. There was consistently only a SuTC with no phasic contraction. The amplitude of the SuTC was 85% of the TC induced by the first carbachol application. The application of atropine (1 micromol/L) to the bath completely blocked SuTC. The carbachol-induced SuTC was insensitive to nicardipine (5 micromol/L) and extracellular polyvalent cations (1 mmol/L, La3+, Co2+, Cd2+, Ni2+ ). Moreover, a similar SuTC was induced even after the complete elimination of extracellular Ca2+ by adding 2 mmol/L EGTA to the Ca2+-free Tyrode solution. To exclude intracellular Ca2+ sources related to the sarcoplasmic reticulum (SR), the effects of SR Ca2+ pump inhibitors, cyclopiazonic acid (CPA, 10 micromol/L) and thapsigargin (0.5 micromol/L) were tested. The carbachol-induced SuTC was insensitive to pretreatment with CPA and/or thapsigargin. To deplete the ryanodine-sensitive Ca2+ pool, muscle strips were repetitively stimulated with caffeine (10 mmol/L) in the presence of 10 micromol/L ryanodine, which did not affect the carbachol-induced SuTC. CONCLUSIONS: Although the characteristics of the carbachol-induced SuTC have not been defined, these results show that a significant proportion of the carbachol-induced contraction in rats is contributed by the SuTC, which is present even in the complete absence of external Ca2+. The SuTC was not affected by limiting the contributions of internal Ca2+ sources. This suggests that the SuTC in rat bladders is unrelated to known Ca2+ mobilization mechanisms.

Animals↗
PubMed1999

Classification of the first web space free flap of the foot and its applications in reconstruction of the hand.

Owing to its unique anatomic arterial supply and dual nerve innervation, the first web space of the foot can be used to harvest various sizes and shapes of flaps, which the authors have classified into four types according to their usage in hand reconstruction. This in turn depends on the site, shape, and size of the soft-tissue defect in the hand. Web skin flaps (n = 8) were used in prevention of contracture in the first web space and for proximal finger reconstruction. Two-island skin flaps (n = 4) were used to resurface the pulp defect in two adjacent fingers. In severe adduction contracture of the first web space, fill-up web flaps (n = 10) were used to replace the volume defect after a release procedure in the hand. Adjuvant web flaps (n = 9) were used in wrap-around procedures, in dorsalis pedis flap transfer, and in vascularized joint transfer to supplement the main flaps and to restore sensation in the reconstructed area. In the past 10 years up to February of 1998, a total of 31 patients with soft-tissue defects in the hand and fingers were reconstructed using the web space free flap with flap survival rate of 100 percent. The mean static 2-point discrimination was 8.5 (7.2 to 10) mm, and the mean first web angle was 86 degrees. The advantage of the first web space flap from the foot is that it can easily be harvested to match various sizes and shapes of defects in the hand and fingers. In addition, because of the anatomic similarity in contour, thickness, texture, and nerve innervation with the hand, the sensory restoration is excellent with minimal morbidity at the donor site. By classifying the flaps into four types according to various sizes, shapes, and the site from which the flap are harvested, clinical usefulness in various types of hand and finger reconstruction was confirmed.

Adolescent↗
PubMed1999

Prevention and treatment of wide scar and alopecia in the scalp: wedge excision and double relaxation suture.

The visible linear scar of the scalp is a cosmetically serious complication of a scalp incision in scalp surgery, forehead lift, and craniofacial surgery, especially on the temporal scalp. Its causes are cicatrical alopecia and scar widening. To solve this problem, we performed the wedge excision of the scalp and the double relaxation suture of the galea in 2 patients undergoing facial surgery through the coronal approach and in 15 patients with scalp alopecia ranging from 0.5 to 3.0 cm in width. The wedge excision using the beveling incision at an angle of 30 degrees to the hair follicles preserves the deep hair follicles of the flap margins and allows the hair to grow into the scar, eventually preventing cicatricial alopecia and camouflaging the linear scar. The double relaxation suture of the trimmed galea with nonabsorbable suture with or without the relaxation incision minimizes skin tension for a long time, eventually preventing scar widening. This procedure was followed by the superficial skin suture for maintaining the skin sutures for a long time and avoiding the injury of the superficial hair follicles. In all patients, we observed an excellent cosmetic result of unnoticed scar line without complications during the follow-up period of 10 weeks to 6 months.

Adolescent↗
PubMed1999

Pure orbital blowout fracture: new concepts and importance of medial orbital blowout fracture.

Pure orbital blowout fracture first occurs at the weakest point of the orbital wall. Although the medial orbital wall theoretically should be involved more frequently than the orbital floor, the orbital floor has been reported as the most common site of pure orbital blowout fractures. A total of 82 orbits in 76 patients with pure orbital blowout fracture were evaluated with computed tomographic scans taken on all patients with any suspicious clinical evidence, including nasal fracture. Isolated medial wall fracture was most common (55 percent), followed by medial and inferior wall fracture (27 percent). The most common facial fracture associated with medial wall fracture was nasal fracture (51 percent), not inferior wall fracture (33 percent). This finding suggests that the force causing nasal fracture is an important causative factor of pure medial wall fracture as the buckling force from the medial orbital rim. Of patients with medial wall fractures, 25 percent had diplopia and 40 percent had enophthalmos. On plain radiographs, diagnostic signs were found in 79 percent of medial wall fractures and in 95 percent of inferior wall fractures. On computed tomographic scans, late enophthalmos was expected in 76 percent of medial wall fractures. Therefore, the medial orbital blowout fracture may be an important cause of late enophthalmos, because it has a high incidence of occurrence, a low diagnostic rate, and a high severity of defect. Among the causes of limitation of ocular motility, muscle traction of the connective septa and direct muscle injury were found frequently, but true incarceration of the muscle was extremely rare in all fractures. The medial and inferior orbital walls are clearly demarcated by the bony buttress, which is an important structure supporting these orbital walls. Its buttress was closely correlated with the fracture of these orbital walls. Most orbital blowout fractures without collapse of the bony buttress had a trapdoor fracture with or without small fragments of punched-out fracture.

Adolescent↗
PubMed1999

Fist position for skin grafting on the dorsal hand: I. Analysis of length of the dorsal hand surgery in hand positions.

In skin grafting for reconstruction of burns and contracture deformities of the dorsal hand, the hand is kept in a proper position to provide the greatest amount of skin and to avoid the secondary functional deformity. The safe position has been commonly used for immobilizing the hand, but this is to protect the hand function rather than to provide maximal surface for skin grafting. Split-thickness skin graft contracts up to 30 to 50 percent of the original size owing to secondary contraction. If insufficient skin is grafted, contracture deformity of the dorsal hand may occur. To graft the greatest amount of skin on the dorsal hand, the hand should be kept preoperatively in a position flexing all joints of the wrist, metacarpophalangeal joints, and interphalangeal joints and maximally stretching the dorsal hand (a fist position). We studied the surface length of the dorsal hand between the wrist, the metacarpophalangeal joint, and the eponychium in the anatomic, safe, and fist positions of the right hand in 60 adults. Difference of total length between the anatomic and safe positions was not statistically significant (p > 0.05). The total length in a fist position was significantly increased in comparison with the other two positions (p < 0.05). In a fist position compared with the safe position, the increase in length of the dorsal surface of the proximal hand was 11 to 20 percent except in the thumb, and the increase in length of the dorsal surface of the finger was 12 to 17 percent. The increase in total length of a fist position was about 9 mm (7 to 8 percent) in the thumb and 20 to 32 mm (14 to 18 percent) in the index to little fingers. It suggests that the safe position fails to provide an increased dorsal hand surface area for skin grafting compared with the anatomic position. The greatest amount of skin can be grafted in a fist position. Hand immobilization in a fist position for 7 to 9 days after skin grafting has not resulted in irrevocable joint stiffness in our experience. If injury of the deep structures is not present, the hand should be immobilized in a fist position before skin grafting on the dorsal hand.

Adult↗
PubMed1999

Effect of cilostazol on the neuropathies of streptozotocin-induced diabetic rats.

OBJECTIVES: This study examined the effect of cilostazol, a potent phosphodiesterase inhibitor, on the progression of neuropathies associated with streptozotocin-induced diabetes mellitus in Sprague-Dawley rats. METHODS: Eight weeks after streptozotocin treatment, a pelleted diet containing 0.03% cilostazol (15 mg/kg body weight) was given for four weeks. Body weight, blood glucose level, motor nerve conduction velocity (MNCV), myelinated fiber density and size distribution of sciatic nerves were compared between age-matched normal rats (Group 1), control diabetic rats (Group 2) and cilostazol-treated diabetic rats (Group 3). RESULTS: Body weight was significantly reduced and blood glucose level was significantly increased in diabetic rats (Group 2 and 3) compared to normal rats. MNCV and cAMP content of sciatic nerves were significantly reduced in diabetic rats 12 weeks after streptozotocin treatment. Myelinated fiber size and density were also significantly reduced, and thickening of the capillary walls and duplication of the basement membranes of the endoneural vessels were observed in the diabetic rats. Whereas both body weight and blood glucose level of Group 3 did not differ significantly from those of Group 2, cilostazol treatment significantly increased MNCV and cAMP content of sciatic nerves in Group 3 but not to the levels observed in Group 1. MNCV positively correlated with cAMP content of sciatic nerves (r = 0.86; p < 0.001). Cilostazol treatment not only restored myelinated fiber density and size distribution but reversed some of the vascular abnormalities. CONCLUSION: These findings suggest that a reduced cAMP content in motor nerves may be involved in the development of diabetic neuropathy, and that cilostazol may prevent the progression of diabetic neuropathy by restoring functional impairment and morphological changes of peripheral nerves.

Animals↗
PubMed1998

Horizontal cells of the rat retina show choline acetyltransferase- and vesicular acetylcholine transporter-like immunoreactivities during early postnatal developmental stages.

We examined cholinergic neurons in the developing rat retina; an antiserum against choline acetyltransferase (ChAT) and an antiserum against vesicular acetylcholine transporter (VAChT) were used. From postnatal day 4 (P4) to P10, ChAT- and VAChT-like immunoreactivities were seen in cells which were located in the outer part of the inner nuclear layer. These cells had relatively large cell bodies and extended several transversely oriented processes. Double fluorescence immunohistochemistry using an antiserum against calbindin D-28K, a specific marker for the horizontal cells, revealed that all of ChAT- or VAChT-labeled cells showed calbindin D-28K-like immunoreactivity. These cells were no longer immunostained after P11. Thus, acetylcholine was considered to be transiently synthesized in the horizontal cells during early postnatal developmental stages in the rat retina.

Acetylcholine↗
PubMed1998

Sequencing and chromosomal localization of the RA138 gene encoding a rice allergenic protein.

A cDNA clone (RA138) encoding a rice allergenic (RA) protein has been isolated during a large-scale random sequencing of a cDNA library prepared from developing seeds. The nucleotide sequence of the RA138 gene contained an open reading frame (ORF, 477 bp) encoding a 17 kDa protein. The amino acid sequence deduced from the ORF was composed of 159 amino acid residues and was highly homologous to those from RA genes previously isolated, such as RA5 (92% identity), RA14 (73%), and RA17 (68%). The protein contained 10 cysteine residues that were conserved in the alpha-amylase/trypsin inhibitor family including RA proteins. Excluding a putative signal peptide consisting of 26 amino acid residues, the mature protein would be 14.4 kDa in size and have a pI of 7.0. DNA gel blot analysis under high stringency conditions indicated that multiple copies of the RA138 gene were present in the rice genome. The chromosomal location of the RA138 gene has been identified on chromosome 7 in a segregation analysis using a population of 164 recombinant inbred lines derived from a cross between Milyang 23 and Gihobyeo. The locus that may contain multiple copies of the RA138 was located between RFLP markers RG477A and C492 with genetic distances of 10.7 cM and 6.7 cM, respectively.

Allergens↗
PubMed1998

Immunocytochemical localization of aquaporin 1 in the rat retina.

Aquaporins transport water through membranes of various tissues, thereby playing crucial roles in a number of physiological processes. Aquaporin 1 (AQP1, also known as CHIP, channel forming integral membrane protein of 28 kDa) is the first identified protein to function as a water channel and has been recently shown to be present in the rat retina. This study was conducted to examine the cellular localization of AQP1 in the rat retina by immunocytochemistry using antisera against AQP1. The AQP1-like immunoreactivity was present in a certain population of amacrine cells and in the proximal processes of Müller cells. Thus, AQP1 appears to be important in the retinal homeostasis.

Animals↗