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J H Lim

Publications and source records attributed to J H Lim.

At least 91 records · Page 5Linked to original sources
PubMed1997

Activity-dependent regulation of calcium-binding proteins in the developing rat olfactory bulb.

Intracellular calcium, important in a variety of second messenger cascades, is regulated in part by calcium-binding proteins such as calretinin, parvalbumin, and calbindin. These proteins are highly concentrated in the rat main olfactory bulb and are localized in distinct neuronal populations. In the present study, postnatal expression was characterized immunohistochemically in normal rats and in rats with functional olfactory deprivation caused by unilateral naris closure, a manipulation that attenuates electrical activity in the bulb. Bulbs were examined from rats that had undergone naris closure or sham surgery on either postnatal day 1 (P1) or P30 and were allowed varying subsequent survival times. Each of the calcium-binding proteins showed both distinct patterns of early expression and differential susceptibility to olfactory restriction. For example, at P10, the densest immunoreactivity was observed for calretinin, a protein whose expression was the least affected by naris closure. After occlusion from P1-P30, there was a 30% reduction in the density of calbindin-immunoreactive profiles in the glomerular layer, and parvalbumin-immunoreactive profiles were reduced by 64% in the external plexiform layer. Unlike many other changes induced by deprivation, the effects of olfactory restriction on calbindin and parvalbumin expression were not age dependent: naris closure from P30-P60 caused similar substantial decreases in calbindin and parvalbumin immunoreactivities. These data demonstrate that the expression of calbindin and parvalbumin in rat bulb is regulated, in part, by afferent activity that is associated with full sensory experiences. The reductions of these calcium-binding proteins following olfactory deprivation are likely to be commensurate with altered control of intracellular calcium.

Animals↗
PubMed1997

The crystal structure of an Fe-superoxide dismutase from the hyperthermophile Aquifex pyrophilus at 1.9 A resolution: structural basis for thermostability.

Superoxide dismutase (SOD) from Aquifex pyrophilus, a hyperthermophilic bacterium, is an extremely heat-stable enzyme that maintains about 70% of its activity after heat treatment for 60 minutes at 100 degrees C. To understand the molecular basis of thermostability of this enzyme, we have determined the crystal structure of A. pyrophilus superoxide dismutase (Ap SOD), an Fe containing homotetrameric enzyme, at 1.9 A resolution, and compared it with SOD structures from a mesophile and a thermophile, and other enzyme structures from other hyperthermophiles. The structure has been refined to a crystallographic R-factor (I > 2sigma) of 17.0% and R-free (I > 2sigma) of 19.9%. While the overall structure of the Ap SOD monomer is similar to the other SODs, significant conformational differences are observed in a highly variable loop region and the C-terminal helix. The conformational differences in these regions alter the subunit arrangement of this enzyme and generate a very compact tetramer. Structural comparisons of three SODs have revealed that Ap SOD has some stabilizing features at both the tertiary and the quaternary structural level: The Ap SOD monomer contains a large number of ion-pairs and the Ap SOD tetramer has a dramatically increased buried surface area per monomer. Comparisons of the Ap SOD structure with that of other known enzymes from hyperthermophiles reveal that the increased number of intrasubunit ion-pairs is a common feature.

Amino Acid Sequence↗
PubMed1997

Cloning and expression of superoxide dismutase from Aquifex pyrophilus, a hyperthermophilic bacterium.

A superoxide dismutase (SOD) gene of Aquifex pyrophilus, a marine hyperthermophilic bacterium, was cloned, sequenced, expressed in Escherichia coli, and its gene product characterized. This is the first SOD from a hyperthermophilic bacterium that has been cloned. It is an iron-containing homo-oligomeric protein with a monomeric molecular mass of 24.2 kDa. The DNA-derived amino acid sequence is more similar to those of known Mn- and Fe-SODs from thermophilic archaea than of Cu, Zn-SODs. The metal binding residues found in all SOD sequences from different species are also conserved in A. pyrophilus SOD. The protein is biochemically active only as an oligomer and is resistant to thermal denaturation.

Amino Acid Sequence↗
PubMed1997

Protection of ischemic hippocampal neurons by ginsenoside Rb1, a main ingredient of ginseng root.

Our previous study showed that the oral administration of red ginseng powder before but not after transient forebrain ischemia prevented delayed neuronal death in gerbils, and that a neuroprotective molecule within red ginseng powder was ginsenoside Rb1. However, it remains to be clarified whether or not ginsenoside Rb1 acts directly on the ischemic brain, and the mechanism by which ginsenoside Rb1 protects the ischemic CA1 neurons is not determined. Without elucidation of the pharmacological property of ginsenoside Rb1, the drug would not be accepted as a neuroprotective agent. The present study demonstrated that the intracerebroventricular infusion of ginsenoside Rb1 after 3.5 min or 3 min forebrain ischemia, precluded significantly the ischemia-induced shortening of response latency in a step-down passive avoidance task and rescued a significant number of hippocampal CA1 neurons from lethal ischemic damage. The intracerebroventricular infusion of ginsenoside Rb1 did not affect hippocampal blood flow or hippocampal temperature except that it caused a slight increase in hippocampal blood flow at 5 min after transient forebrain ischemia. Furthermore, ginsenoside Rb1 at concentrations of 0.1-100 fg/ml (0.09-90 fM) rescued hippocampal neurons from lethal damage caused by the hydroxyl radical-promoting agent FeSO4 in vitro, and the Fenton reaction system containing p-nitrosodimethylaniline confirmed the hydroxyl radical-scavenging activity of ginsenoside Rb1. These findings suggest that the central infusion of ginsenoside Rb1 after forebrain ischemia protects hippocampal CA1 neurons against lethal ischemic damage possibly by scavenging free radicals which are overproduced in situ after brain ischemia and reperfusion. The present study may validate the empirical usage of ginseng root over thousands of years for the prevention of cerebrovascular diseases.

Animals↗
PubMed1996

Ginseng root prevents learning disability and neuronal loss in gerbils with 5-minute forebrain ischemia.

The present study was designed to investigate the possible neuroprotective activity of ginseng roots in 5-min ischemic gerbils using a step-down passive avoidance task and subsequent neuron and synapse counts in the hippocampal CA1 region. The following drugs were administered for 7 days before the induced ischemia: red ginseng powder (RGP), crude ginseng saponin (CGS), crude ginseng non-saponin (CGNS), and pure ginsenosides Rb1, Rg1 and Ro. Oral administration of RGP significantly prevented the ischemia-induced decrease in response latency, as determined by the passive avoidance test, and rescued a significant number of ischemic hippocampal CA1 pyramidal neurons in a dose-dependent manner. Intraperitoneal injections of CGS exhibited a similar neuroprotective effect. CGNS had a significant but less potent protective effect against impaired passive avoidance task and degeneration of hippocampal CA1 neurons. Ginsenoside Rb1 significantly prolonged the response latency of ischemic gerbils and rescued a significant number of ischemic CA1 pyramidal neurons, whereas ginsenosides Rg1 and Ro were ineffective. Postischemic treatment with RGP, CGS or ginsenoside Rb1 was ineffective. The neuroprotective activities of RGP, CGS and ginsenoside Rb1 were confirmed by electron microscopy counts of synapses in individual strata of the CA1 field of ischemic gerbils pretreated with the drugs. These findings suggest that RGP and CGS are effective in the prevention of delayed neuronal death, and that ginsenoside Rb1 is one of the neuroprotective molecules within ginseng root.

Animals↗
PubMed1996

Fingertip replantations: clinical evaluation of 135 digits.

From July 1985 to February 1993, 135 digits in 119 patients with complete amputations at or distal to the distal interphalangeal joint (zone I for amputations distal to the nail base of zone II for amputations between the distal interphalangeal joint and the nail base) were replanted using a microsurgical technique at Korea University Guro Hospital. Because of the high social value placed on body form and function, the indication for replantation was extended to cases with severe soft-tissue injuries and attempted replantation as a routine procedure in nearly all distal amputation cases. The overall survival rate was 78 percent, with the survival rate for zone I being 70 percent and that for zone II reaching 86 percent. Even in cases with severe soft-tissue injury, the survival rate was high, with viability in avulsion injuries and crush injuries reaching 75 percent each. The most common type of vascular repair in zone I cases was revascularization of one artery only and no vein repair (87 percent). Of these cases, interpositional vein grafts were used in 65 percent. In zone II cases, the most common combination repair was one artery and one vein anastomosis (70 percent), with interpositional vein grafts for arterial anastomosis in 49 percent; most of the venous repair was feasible by the direct method (78 percent). The follow-up period ranged from 1 month to 5 years with a mean of 14.8 months; 52 patients were followed-up for more than 6 months. In 52 long-term follow-up patients, the average two-point discrimination was 8 mm. Patient satisfaction, aesthetically and functionally, was high (91 percent).

Adult↗
PubMed1996

Eight cases of nine-digit and ten-digit replantations.

Amputations involving nine and all ten digits are very rare because of the different lengths of the digits, and it is also unusual to have all digits suitable for replantation. At Korea University Guro Hospital, from March 1987 to April 1992, three cases of 10-digit and five cases of 9-digit complete amputations were replanted by microsurgical technique. All eight cases involved young, healthy male patients, and the causes of amputation were either a cutter of press machine. The replantations were done under general anesthesia simultaneously on both hands by eight microsurgeons divided into a total of four teams. The operating times ranged from 19 to 31 hours, and the total amounts of transfused blood ranged from 6 to 38 pints. The warm ischemic times ranged from 10 minutes to 15 hours, and the cold ischemic times ranged from 3 to 29 hours. The sequence of replantation was radial digit to ulnar digit. In five of the eight patients, all of the replanted digits survived. Necrosis occurred in one and two digits in two patients with nine-digit replantations. Also, necrosis occurred in three digits in a patient who had had nine digits amputated by a press machine, sustaining severe crush injuries. The overall survival rate was 92 percent. In multidigit replantations involving 9 or 10 digits, there are a number of problems that must be overcome, including a long operating time, long ischemic times, and a large amount of blood loss. The long ischemic times were not critically related to survival rate. The total amount of blood transfused was reduced from 38 pints in one of the initial cases to 6 pints by intermittent use of the pneumatic tourniquet and venous anastomosis before arterial anastomosis. Static two-point discrimination ranged from 3 to 22 mm, and palm to pulp distance ranged from 0 to 7 cm, 1 to 5 years postoperatively. Grasping power ranged from 13 to 65 lb, and pinching power ranged from 5 to 26 lb, which was 42 and 50 percent of the average power of a Korean adult male, respectively. All eight patients returned to work and are satisfied with the result, functionally and aesthetically.

Adolescent↗
PubMed1996

Focal appendicitis confined to the tip: diagnosis at US.

PURPOSE: To evaluate the diagnostic value of graded-compression ultrasonography (US) for the diagnosis of focal appendicitis confined to the tip. MATERIALS AND METHODS: During a 4-year period, US was performed in 1,450 patients with clinically suspected acute appendicitis. Of these patients, 443 had appendicitis at pathologic examination, 20 of whom had focal appendicitis confined to the tip. Focal appendicitis confined to the tip was defined as occurring when the resected specimen had inflammation only at the distal third of the appendix. RESULTS: Of 20 patients with focal appendicitis confirmed at pathologic examination, 17 patients (85%) had focal appendicitis that was correctly diagnosed at US. The remaining three patients' appendices were diagnosed at US as normal (false-negative cases). Five patients had perforation at the tip, and one patient had an appendicolith. CONCLUSION: Although US appears to be fairly accurate in the diagnosis of focal appendicitis confined to the tip, the entire length of the appendix should be evaluated in order to avoid a false-negative diagnosis.

Acute Disease↗
PubMed1996

Appendicitis: usefulness of color Doppler US.

PURPOSE: To assess whether color Doppler ultrasonography (US) can help diagnose early acute appendicitis in appendices of equivocal size at gray-scale US. MATERIALS AND METHODS: In a retrospective study, color Doppler US findings were evaluated in 20 individuals with proved normal appendix at barium enema examination and in 50 patients in whom pathologic findings confirmed acute appendicitis. In a prospective study, the diagnostic value of hyperemia in the wall of the appendix in differentiating a normal from an inflamed appendix was evaluated in 26 patients with appendices of equivocal size (5-7 mm in maximal outer diameter) at grayscale US. RESULTS: In the retrospective study, 44 of the 50 patients had hyperemia at color Doppler US. The remaining six patients had no hyperemia, and pathologic findings confirmed gangrenous appendices. The 20 patients with proved normal appendix at barium enema examination had no detectable blood flow in the wall. In the prospective study, 10 of 26 patients had hyperemia at color Doppler US, and pathologic findings confirmed early acute appendicitis. Results of barium enema examination (n = 12) or clinical follow-up (n = 4) confirmed no appendicitis in the remaining 16 patients. CONCLUSION: Hyperemia in the wall of the appendix at color Doppler US is a sensitive indicator for inflammation. A simple additional color Doppler US examination may be helpful in the diagnosis of early acute appendicitis when an appendix is well depicted and is equivocal in size at gray-scale US.

Acute Disease↗
PubMed1996

Papilla of Vater: normal sonographic appearance.

To ascertain the normal appearance of the papilla of Vater with transabdominal sonography, 37 subjects without biliary or pancreatic disease were examined with high resolution sonographic equipment. The normal appearance of the papilla and its frequency of visualization were evaluated. Characteristically the papilla of Vater appeared as a blind-ending cylindrical or oval structure projecting into the duodenal lumen at the distal end of the common bile duct. The diameter ranged from 3 mm to 6 mm (mean, 4.4 mm). Among the 37 subjects, the papilla was well demonstrated in 28 subjects (76%), fairly well demonstrated in five subjects (14%), and not demonstrated in four subjects (10%). Awareness of the normal sonographic appearance of the papilla of Vater on transabdominal sonography may be helpful in the evaluation of periampullary pathology.

Ampulla of Vater↗
PubMed1994

Loculated fluid collections in hepatic fissures and recesses: CT appearance and potential pitfalls.

The peritoneum invaginates into the liver parenchyma normally, as a normal anatomic variation, or pathologically and then fissures and furrows are formed. There are four normal fissures: fissures for the ligamentum teres, ligamentum venosum, and gallbladder and the transverse fissure. Fissures caused by normal anatomic variations include accessory fissures and furrows created by diaphragmatic indentation. Pathologic fissures occur secondary to traumatic or iatrogenic causes or as a result of liver cirrhosis. When ascites, hemoperitoneum, or infected ascites is loculated in the fissures or recesses, it may be mistaken for a liver cyst, intrahepatic hematoma, or liver abscess. When peritoneally disseminated tumor cells are implanted into these spaces, they may mimic intrahepatic focal lesions. Because the clinical consequences for these entities are very different, exact localization of the lesions may be crucial in the diagnosis and management of the lesions. Complete understanding of the liver surface anatomy and awareness of these situations may prevent a misdiagnosis of a focal intrahepatic abnormality.

Humans↗
PubMed1994

Sonography of the stomach: an in vitro study to determine the anatomic cause of inner hyperechoic and hypoechoic layers of the gastric wall.

OBJECTIVE: Sonography of the normal gastric wall delineates five distinct layers: from the luminal side, a first, inner hyperechoic layer; a second, hypoechoic layer; a third, middle hyperechoic layer; a fourth, hypoechoic layer; and a final, outer hyperechoic layer. The anatomic origin of the inner two sonographic layers has been a matter of controversy. To verify the histologic origin of the inner two sonographic layers, we attempted to correlate sonographic and histologic layers of resected gastric specimens. Because we hypothesized that the fluid covering the mucosa and the mucosa may be responsible for the sonographic inner two layers of the stomach, we selected specimens in which the mucosa was sloughed or thickened. MATERIALS AND METHODS: We selected five resected gastric specimens with ulcerative carcinoma in which the mucosa was totally sloughed, one specimen with a mucosal polyp, and two specimens with a polypoid lesion and partial surface ulceration. The gastric specimens were immersed in normal saline and examined with 5-MHz high-resolution sonographic equipment. Sonographic findings were correlated with gross and microscopic pathologic findings. Two phantoms were immersed in normal saline and examined with the same technique to evaluate the thickness of the sonographic interface between water and phantoms. RESULTS: The inner hyperechoic layer was constant in thickness, measuring 1 mm, and covered the surface of the normal areas and the areas where the mucosa was lost or thickened. The hypoechoic layer underlying the hyperechoic layer was obliterated where the mucosa was defective and thickened where the mucosa was thickened. The sonographic interface between water and phantoms was 1 mm thick. CONCLUSION: Our results show that the inner hyperechoic layer of the stomach seen on sonograms is due to echoes arising from the interface between fluid in the gastric lumen and the mucosal surface. The underlying hypoechoic layer is caused by the mucosa itself.

Carcinoma↗
PubMed1994

Exophytic adenocarcinoma of the stomach: CT findings.

OBJECTIVE: Exophytic adenocarcinomas of the stomach are tumors that have large extraluminal portions. Exophytic growth of gastric carcinoma is rare, and such tumor may be confused with gastric leiomyosarcoma. The purpose of this study was to assess the CT findings of exophytic adenocarcinoma of the stomach and to determine their value in distinguishing between it and gastric leiomyosarcoma. MATERIALS AND METHODS: Twenty patients with exophytic adenocarcinomas of the stomach confirmed by surgery or endoscopic biopsy were included in the study. CT scans were assessed retrospectively for the size, location, and character of the mass and the presence of adjacent thickening of the gastric wall and outlet obstruction. RESULTS: The masses were from 5 to 14 cm in diameter (mean, 9 cm). The mass was in the gastric antrum in 11 cases, the body of the stomach in six cases, the body and antrum in two cases, and the gastric fundus and body in one case. CT showed an exogastric mass with a variable degree of internal low density or necrosis in all 20 cases. Thickening of the gastric wall adjacent to the mass appeared to be a specific finding of exogastric adenocarcinoma (n = 14); it was not seen in reported cases of leiomyosarcoma. Gastric outlet obstruction was seen in four cases, and ulcer was detected in eight cases. The degree of low density or necrosis within the mass was minimal in eight cases, moderate in seven cases, and severe in five cases. CONCLUSION: Our results suggest that CT findings of thickening of the gastric wall adjacent to an exogastric mass, representing spread of cancer to adjacent gastric wall, and/or gastric outlet obstruction are typical of exophytic adenocarcinoma of the stomach and allow distinction between it and gastric leiomyosarcoma.

Adenocarcinoma↗
PubMed1994

Sonography of inflammatory bowel disease: findings and value in differential diagnosis.

OBJECTIVE: Inflammatory bowel diseases produce segmental or diffuse mural thickening of the intestine that can be detected and evaluated by using sonography. The purpose of this study was to evaluate the sonographic findings and determine their diagnostic value in patients with inflammatory bowel diseases. MATERIALS AND METHODS: We reviewed sonograms of 81 patients with inflammatory bowel diseases. The findings were compared with those of barium study, colonoscopy, and surgery. Forty-five patients had tuberculous enterocolitis, 13 had ulcerative colitis, eight had Crohn's disease, five had ischemic colitis, two had Behçet's syndrome, and eight had unspecified colitis. Diagnosis was based on surgical and pathologic findings in 23; results of barium study and endoscopic biopsy in 20; and results of barium study, colonoscopic findings, and clinical findings in 38. RESULTS: Seventy-two patients (89%) had sonograms that showed segmental or diffuse mural thickening and a paucity of luminal content in the involved bowel. Involved areas were the ileocecal region in the cases of tuberculous enterocolitis and Behçet's syndrome, the left side of the colon in ulcerative colitis, and the colon and terminal part of the ileum in Crohn's disease. In ischemic colitis, the distribution of involved bowel was nonspecific. Sonographic findings correlated well with the findings of barium enema or colonoscopy in terms of the involved segments of the bowel. Mesenteric lymphadenitis, omental thickening, and ascites were frequently observed in cases of tuberculous enterocolitis. CONCLUSION: Sonographic evidence of mural thickening of the bowel with a paucity of luminal content may be helpful in the detection of inflammatory bowel diseases. However, the findings are nonspecific, and the differential diagnosis must be related to the specific segment of the bowel involved.

Barium Sulfate↗