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Biomedical subjects

S I Lee

Publications and source records attributed to S I Lee.

At least 19 recordsLinked to original sources
PubMed1992

Viral small nuclear ribonucleoproteins bind a protein implicated in messenger RNA destabilization.

Herpesvirus saimiri (HVS) is one of several primate viruses that carry genes for small RNAs. The five H. saimiri-encoded U RNAs (HSURs) are the most abundant viral transcripts expressed in transformed marmoset T lymphocytes. They assemble with host proteins common to spliceosomal small nuclear ribonucleoproteins (snRNPs). HSURs 1, 2, and 5 exhibit sequences at their 5' ends identical to the AUUUA motif, which targets a number of protooncogene, cytokine, and lymphokine mRNAs for rapid degradation. We show that a 32-kDa protein previously demonstrated to bind to the 3' untranslated region of several unstable messages can be UV crosslinked specifically to HSUR 1, 2, and 5 transcripts in vitro, as well as to endogenous HSUR snRNPs. Our results suggest an unusual role for these viral snRNPs: HSURs may function to attenuate the rapid degradation of certain cellular mRNAs, thereby facilitating viral transformation of host T lymphocytes.

Base Sequence↗
PubMed1992

Histologic study of chronic active hepatitis C; comparison with chronic active hepatitis B.

Reports on the histologic findings of chronic active hepatitis C (CAH-C) have been rare, and the characteristic histologic findings of CAH-C have been not yet determined. To compare the differences in the histologic findings between CAH-C and chronic active hepatitis B (CAH-B) group, we analyzed the histologic findings of 19 patients with CAH-C, who had positive tests for HCV-antibody by EIA, and 19 patients with CAH-B who had negative tests for HCV-antibody but positive tests for HBsAg by RIA. Histologic features were analyzed between the CAH-C and CAH-B groups using a scoring system which is modified from Knodell's histologic activity index-looking at portal inflammation, periportal necroinflammation, portal fibrosis, focal necrosis, regeneration, polyploid nuclear change, sinusoidal lymphocytic reaction and fatty change. Portal inflammatory cell infiltrations with prominent lymphocytes and follicular arrangement were more frequent in the CAH-C group (10 of 19 cases) than in the CAH-B group (5 of 19 cases). Severe sinusoidal lymphocytic reactions were also more prominent in the CAH-C group (11 of 19 cases) than in the CAH-B group (6 of 19 cases). However, periportal necroinflammation, portal fibrosis, focal hepatic necrosis, regeneration and polyploid nuclear changes were more prominent in the CAH-B group than in the CAH-C group. In conclusion, follicular portal inflammation and severe sinusoidal lymphocytic reactions were common histologic findings in serologically proven CAH-C when compared to CAH-B.

Adult↗
PubMed1991

Mechanism of secretagogue-induced HCO3- and Cl- loss from rat parotid acini.

The Cl(-)- and HCO3(-)-dependent components of muscarinic agonist (carbachol)-induced K+ loss from a rat parotid mince were studied using 86Rb+ as a K+ marker. Both components of 86Rb+ loss were blunted by K+ and Cl- channel blockers and by removal of extracellular Ca2+, consistent with the hypothesis that 86Rb+ loss occurs via a Ca(2+)-activated K+ channel and that this cation loss serves to electrically balance a concomitant loss of the corresponding anion via one or more conductive pathways (channels). Two tissue "pools" of 86Rb+ were observed, a carbachol-sensitive pool and a carbachol-insensitive pool (approximately 70 and approximately 30% of the total 86Rb+ content, respectively). There was no evidence for a time-dependent desensitization of the muscarinic response of the carbachol-sensitive pool. Cl(-)-dependent 86Rb+ loss was not affected by HCO3- addition, suggesting that both Cl- and HCO3- secretion are accompanied by 86Rb+ loss from the same pool and thus occur from the same cells. HCO3(-)-dependent 86Rb+ loss was not enhanced by lowering the extracellular Na+ concentration, indicating that the HCO3- exit pathway is not a Na(+)-HCO3- symport. The data are consistent with the postulate that Cl- and HCO3- are secreted by rat parotid acinar cells via the same or very similar conductive transport pathways in response to muscarinic stimulation.

Animals↗
PubMed1991

Somato-somatic referred pain caused by suprasegmental spinal cord tumor.

Tactile stimulation of a coin-sized area in a T-2 dermatome consistently triggered a lancinating pain in the ipsilateral C-8 dermatome in a 38-year-old woman. The SEP and an MRI led to a diagnosis of a tumor at the left cervico-medullary junction, much higher than the clinically suspected level. Surgical exploration revealed an exophytic glioma, and the pain was abolished postoperatively. Ephaptic transmission at the tumor site was suspected as a pathophysiologic mechanism.

Adult↗
PubMed1990

Herpesvirus saimiri U RNAs are expressed and assembled into ribonucleoprotein particles in the absence of other viral genes.

Marmoset T lymphocytes transformed by herpesvirus saimiri contain a set of five virally encoded U RNAs called HSUR1 through HSUR5. HSUR genes have been individually transfected into a nonlymphoid, nonsimian cell line (HeLa cells) in the absence of any other coding regions of the herpesvirus saimiri genome. The levels of HSUR1 through HSUR4 in HeLa transient-expression systems are comparable to those found in virally transformed T cells (23 to 91%). In contrast, HSUR5 is expressed at ninefold-higher levels in transfected HeLa cells. Immunoprecipitation experiments show that HSURs expressed in transfected cells bind proteins with Sm determinants and acquire a 5' trimethylguanosine cap structure, as they do in transformed T cells. HSUR1 or HSUR4 particles from transfected HeLa cells migrate between 10S and 15S in velocity gradients, identical to the sedimentation of "monoparticles" produced in virally transformed lymphocytes. We conclude from these transfection experiments that no other herpesvirus saimiri or host-cell-specific gene products appear to be required for efficient expression of the HSUR genes or for subsequent assembly of the viral U RNAs into small nuclear ribonucleoprotein particles. In lymphocytes transformed by herpesvirus saimiri, HSUR small nuclear ribonucleoprotein particles are involved in higher-order complexes that sediment between 20S and 25S. HSUR1, HSUR2, and HSUR5 dissociate from such complexes upon incubation at 30 degrees C, whereas the complex containing HSUR4 is stable to incubation.

Animals↗
PubMed1990

Prolonged confusion following convulsions due to generalized nonconvulsive status epilepticus.

Among patients with a prolonged confusional state after convulsive seizure, we diagnosed 8 cases as generalized nonconvulsive status epilepticus. Six had a history of seizures, and 2 had new onset. The convulsive seizures were generalized in 6 and focal in two. The postictal confusion lasted up to 36 hours in the most prolonged case, and a delayed response to anticonvulsant medications occurred in all cases. The clinical symptoms ranged from mild confusion to coma. Psychiatric manifestations or automatisms were rare. The presumed etiology was due to diverse causes, but a withdrawal state was the most common. EEG demonstrated continuous or nearly continuous generalized ictal discharges of variable morphology. These cases call attention to the fact that some prolonged confusional states following convulsive seizures are in fact due to persistent seizure activity that can be diagnosed by EEG.

Adolescent↗
PubMed1990

Locally advanced unresectable gastric cancer successfully resected after neoadjuvant chemotherapy with FADE regimen.

The prognosis of unresectable advanced gastric cancer is extremely poor. We tried a neoadjuvant chemotherapy in locally advanced unresectable stomach cancer diagnosed by initial explo-laparotomy. After chemotherapy with the FADE regimen (5-fluorouracil + adriamycin + cisplatin + etoposide), the patient was diagnosed clinically as a complete response state on re-staging with radiological gastrointestinal study, fiber-gastroscopy and computerized tomography. During the second-look operation, the advanced cancer was completely resected and the pathological diagnosis was early gastric cancer (EGC) type IIc, stage II (T1N2Mo).

Adenocarcinoma↗
PubMed1990

Circulating immune complexes and cell-mediated immunity in patients with hepatitis B virus associated liver diseases.

The prevalence of circulating immune complexes (CIC), their role and their relationship to cell-mediated immunity in patients with hepatitis B virus associated liver disease are still controversial. This study was designed to investigate the prevalence of CIC and their relationship to viral markers, to subsets of peripheral blood T lymphocytes and to suppressor cell activity in patients with hepatitis B virus associated liver diseases. CIC were positive in 29.3% of 41 healthy HBsAg carriers, 37.8% of 88 patients with hepatitis B virus associated liver diseases, and 15% of 41 healthy subjects by the platelet aggregation test (PAT). The prevalence of CIC in patients with acute hepatitis (40.0%) and in those with cirrhosis (61.5%) was significantly higher than in normal controls (p less than 0.05, p less than 0.005 respectively). There was no correlation between the titer of CIC and serum HBsAg titer or the status of HBeAg, and no significant decrease in the peripheral blood lymphocyte CD4/CD8 ratio in healthy HBsAg carriers (1.39 +/- 0.31) and in patients with liver diseases (1.40 +/- 0.54) compared to the normal controls (1.48 +/- 0.31). Concanavalin A induced suppressor cell activity on IgG producing cells was impaired in healthy HBsAg carriers (34.9%) (p less than 0.005) and in patients with liver diseases (25.3%) (p less than 0.0001), and this change was prominent in patients with chronic active hepatitis and cirrhosis (p less than 0.0001). And there was a significant reverse correlation between concanavalin A induced suppressor cell activity on IgG-producing cells and the titer of CIC in PAT positive patients with hepatitis B virus associated liver diseases. In conclusion, it was suggested that defective suppressor cell function may lead to an increased B cell activation and such activity may account for the presence of CIC.

Acute Disease↗
PubMed1990

Influence of gamma-aminobutyric acid on the changes of blood pressure in rats.

This is an attempt to investigate the effect of gamma-aminobutyric acid (GABA), a well-known major inhibitory neurotransmitter in the central nervous system, on the blood pressure response in rats and to elucidate the mechanism of its action. GABA injected into a femoral vein of the rat produced a dose-related fall in blood pressure followed by a secondary pressor response. The depressor response evoked by GABA was clearly blocked by pretreatment with chlorisondamine, diazepam and picrotoxin but was unaffected by atropine, prazosin and debrisoquin. GABA-induced pressor responses were significantly attenuated by pretreatment with prazosin or picrotoxin, while not affected by atropine, diazepam, debrisoquin and chlorisondamine. These experimental data suggest that GABA causes biphasically depressor and pressor responses in rats, and that the hypotensive activity evoked by GABA may be exerted through activation of GABAergic receptors and hypertensive activity due to stimulation of the adrenergic alpha-receptors, which appears to be associated with GABAergic receptors.

Animals↗
PubMed1990

Endoscopic injection sclerotherapy in patients with bleeding esophageal varices: a retrospective analysis.

Endoscopic injection sclerotherapy has been accepted as the procedure of choice for patients with variceal hemorrhage. To evaluate the efficiency of endoscopic injection sclerotherapy in patients with bleeding esophageal varices, we did a retrospective study of 52 patients (non-sclerotherapy group) with bleeding esophageal varices who were admitted to hospitals and did not receive sclerotherapy and of 50 patients (sclerotherapy group) who received sclerotherapy with ethanolamine oleate. The mortality (sclerotherapy group vs. non-sclerotherapy group: 18.0% vs. 32.7%) during index hospitalization, the bleeding risk factor (the number of rebleeds per patient/month; 1.56 +/- 2.76 vs. 4.96 +/- 9.99: mean +/- SEM) and the mortality due to bleeding (14.0% vs. 36.5%) were higher in the non-sclerotherapy group than in the sclerotherapy group. Only those in Child's class C who received sclerotherapy had a significantly better survival rate than the non-sclerotherapy group (p less than 0.05). Although formal comparisons were not made because of the retrospective nature of this study, endoscopic injection sclerotherapy is effective and appears to be superior to conventional medical treatments.

Adult↗
PubMed1989

Submucosal lymphatic cyst of the stomach--a case report.

A submucosal lymphatic cyst is a thin-walled cyst, lined by flattened lymphatic endothelium, containing thin serous fluid. It rarely causes clinical symptoms, and it is incidentally discovered during fiberoptic panendoscopy or radiologic study in most cases. It is an extremely rare benign tumor of the stomach; however, a submucosal lymphatic cyst should be considered if a pliable and benign submucosal lesion is detected during fiberoptic panendoscopy. We report a case of submucosal lymphatic cyst of the stomach which showed a typical clinical picture. This report is the first case of submucosal lymphatic cyst of the stomach in Korea to the best of our knowledge.

Age Factors↗
PubMed1989

Evaluation of omeprazole as a treatment for gastric and prepyloric ulcer in Korean patients.

The healing efficacy of omeprazole was assessed in 57 Korean patients with endoscopically-proven gastric (GU) and/or prepyloric (PPU) ulcers of at least 5 mm diameter. Fifty-three patients presented with GU, two with PPU and two with both types of ulcer. The maximum ulcer diameter was 5-10 mm in 27 patients and greater than 10 mm in 30 patients. All patients received 20 mg of omeprazole each morning for 4-8 weeks depending on ulcer healing. Ulcer healing rates were comparable using both 'intention to treat' (IT) and 'per protocol' (PP) analyses. Following the IT approach 82% (47 of 57) of patients were healed at 4 weeks and 98% (56 of 57) at 8 weeks. Following the PP approach, the corresponding healing rates were 83% (44 of 53) and 98% (55 of 56), respectively. Smoking was found to have a significant effect on ulcer healing at 4 weeks (P = 0.03), with 96% (26 of 27) of non/occasional smokers healed versus only 69% (18 of 26) of daily/heavy smokers. Ulcer size did not have a significant effect on healing, however. Ulcer symptoms, reported by all patients at entry, disappeared rapidly after commencement of omeprazole therapy. Only four patients reported mild symptoms at 4 weeks and no symptoms were reported at 8 weeks. No clinically significant changes in haematology or clinical chemistry (other than a rise in leucocytes in one patient) and no serious adverse events were observed. In conclusion, omeprazole 20 mg each morning was found to be safe and highly effective for treatment of gastric and prepyloric ulcer in Korean patients, producing a 98% healing rate. Symptom relief was rapid and the drug was well tolerated.

Adult↗
PubMed1988

Four novel U RNAs are encoded by a herpesvirus.

Marmoset T lymphocytes transformed by herpesvirus saimiri contain the first virally encoded U RNAs (called HSURs) to be identified. HSURs assemble into small nuclear ribonucleoproteins of low abundance (less than or equal to 2 x 10(4) copies/cell). They bind proteins with Sm determinants and acquire a 5' trimethylguanosine cap structure. The sequences of HSUR 1 (143 nucleotides), HSUR 2 (115 nucleotides), HSUR 3 (76 nucleotides), and HSUR 4 (106 nucleotides) are related to each other but are distinct from any previously characterized cellular U RNA. The viral genes encoding the HSURs possess conserved enhancer, promoter, and 3' end formation signals unique to U RNA genes. HSUR 1 and HSUR 2 have a similar 5' end sequence that exhibits perfect complementarity to the highly conserved AAUAAA polyadenylation signal. Oligonucleotide directed RNAase H degradation indicates that this 5' end region is available for base pairing interactions within the HSUR 1 and HSUR 2 snRNP particles.

Base Composition↗
PubMed1988

A novel mechanism for the selection of isotype-specific antibody responses: the role of intestinal T cells in the regulation of IgA synthesis by the anti-suppressor circuit.

Within 6 hr of immunization the serum of mice contains a unique form of processed antigen, which consists of a complex of immunoglobulin (Ig) and antigen formed in the presence of a factor derived from the anti-suppressor inducer T cell. This complex binds to and activates the anti-suppressor effector T cell, which eventually leads to the inhibition of suppressor cell function. Both of these cells are present in the spleen (SPL) and play a role in the regulation of antibody responses. The purpose of these studies was to identify the anti-suppressor T cells in gut-associated lymphoid tissue and compare their function to their splenic counterparts. Inducer cells were detected in the Peyer's patches (PP), mesenteric lymph nodes but not in the intra-epithelial lymphocytes. The effector cells, which take up the complexes, were detected in PP and lamina propria lymphocytes but not in the intraepithelial or mesenteric lymph node lymphocytes. Furthermore, the uptake of the complexes correlated with the presence of T cells bearing Ia antigens. The PP and SPL anti-suppressor cells were compared for their ability to enhance the production of IgA and IgG. The data clearly showed that the product of the inducer cell, and the effector cell it activates, not only enhanced the antigen-specific responses but also selected for isotype-specific antibody responses. Cells from SPL enhanced IgG greater than IgA, whereas cells from PP selected for IgA. Thus, the presence in PP of cells in the anti-suppressor circuit and their ability to selectively promote IgA synthesis suggest that this regulatory mechanism plays a significant role in intestinal immune responses.

Animals↗