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Biomedical subjects

K Yoo

Publications and source records attributed to K Yoo.

At least 19 recordsLinked to original sources
PubMed2003

Serum cytokine profiles in patients with Plasmodium vivax malaria: a comparison between those who presented with and without thrombocytopenia.

One of the peculiar features of Plasmodium vivax malaria in South Korea is the surprisingly high frequency of thrombocytopenia. The mechanism by which this malaria-related thrombocytopenia develops and its role in the pathology and progress of human infection with P. vivax have not yet been completely understood. In the present study, the serum cytokine profiles of cases of P. vivax malaria who presented with thrombocytopenia were compared with those of similar cases who did not have thrombocytopenia at presentation. The subjects were the 94 consecutive cases of P. vivax malaria who presented at five hospitals in South Korea (all near the Demilitarized Zone) between May 2000 and October 2002, 47 of whom had thrombocytopenia at presentation. When mean values and (S.E.) were compared, the thrombocytopenic patients were found not only to be generally older than the non-thrombocytopenic [25.3 (1.1) v. 21.3 (0.18) years; P < 0.001] but also to have presented with higher serum concentrations of aspartate aminotransferase [77.6 (16.6) v. 32.3 (7.4) U/litre; P < 0.0001], alanine aminotransferase [96.7 (19.0) v. 44.7 (12.0) U/litre; P = 0.0001], interleukin-1 [49.9 (7.4) v. 23.7 (5.1) pg/ml; P < 0.001], interleukin-6 [174.9 (26.4) v. 57.3 (14.6) pg/ml; P = 0.001], interleukin-10 [308.2 (39.6) v. 137.9 (23.1) pg/ml; P < 0.002] and transforming growth factor-beta [1134.3 (387.5) v. 416.6 (183.8) pg/ml; P < 0.0001], and higher levels of parasitaemia [4345.7 (966.6) v. 1443.8 (222.7) parasites/microl; P = 0.03). The non-thrombocytopenic patients, however, had relatively high total leucocyte counts [5.8 (0.24) v. 5.4 (0.66) leucocytes/nl; P = 0.03]. The thrombocytopenia associated with P. vivax malaria in South Korea therefore appears to be associated with elevated serum concentrations of both pro- and anti-inflammatory cytokines. To define the role of each cytokine in the development of thrombocytopenia during the course of acute P. vivax malaria, further prospective studies are needed.

Adult↗
PubMed2001

Association between insulin-like growth factor-2 and metastases after transcatheter arterial chemoembolization in patients with hepatocellular carcinoma: a prospective study.

BACKGROUND: Hypoxia up-regulates insulin-like growth factor-2 (IGF-2) and thus stimulates the growth of hepatocellular carcinoma (HCC) cells. In the current study, the authors prospectively evaluated changes in plasma IGF-2 levels in HCC patients after transcatheter arterial chemoembolization (TACE), which usually results in hypoxic insult to liver tissue. The authors also examined the association between changes in plasma IGF-2 levels after TACE and HCC progression, especially in relation to metastasis. METHODS: Plasma IGF-2 levels were measured before and 4 weeks after TACE in 46 patients with HCC. Three months after TACE, the patients were evaluated for the occurrence of metastatic HCC. RESULTS: In 13 of the 46 patients, post-TACE plasma IGF-2 levels decreased by > 20% (Group 1) compared with their basal levels; in 18 patients, the IGF-2 levels changed within 20% (Group 2) and in 15 patients the IGF-2 levels increased by > 20% (Group 3). Plasma IGF-2 levels had a tendency to increase in patients with large-sized tumors, high serum alpha-fetoprotein (AFP) levels, and the heterogeneous uptake of iodized oil. Metastatic foci were found in 9 patients in Group 3 (60%), in contrast to only 3 patients in Group 2 (17%) and in none of the patients in Group 1 (P = 0.001). On multivariate analysis, higher Child-Pugh scores and increased plasma IGF-2 levels (Group 3) were found to be independent risk factors for metastasis. CONCLUSIONS: Increased plasma IGF-2 levels after TACE, which are common in patients with large-sized tumors and high serum AFP levels, appear to be associated with the occurrence of metastatic HCC after TACE.

Carcinoma, Hepatocellular↗
PubMed2001

Postmenopausal obesity as a breast cancer risk factor according to estrogen and progesterone receptor status (Japan).

There have been inconsistent results on the association of postmenopausal obesity with breast cancer risk according to the estrogen (ER) and/or progesterone receptor (PR) status in the breast tissue, and this requires further evaluation. This study was designed to assess whether postmenopausal obesity differs according to receptor status. Information on risk factors was obtained from 1154 breast cancer cases and 21714 controls at Aichi Cancer Center Hospital, Nagoya, Japan between 1988 and 1992. The receptor status was known for 40% of cases. Obese postmenopausal women showed an increased risk of breast cancer (odds ratio (OR) for 5 kg of current weight=1.17, 95% confidence interval (CI)=1.10-1.25; OR for 1 kg/m(2) of body mass index (BMI)=1.07, 95% CI=1.04-1.10). The elevated OR was strongest for ER-positive, as well as with PR-positive, breast cancer among postmenopausal women who had a high BMI. The risk did not differ significantly according to ER status. However, obesity indices among postmenopausal women differed with borderline significance according to PR status. These results are consistent with the hypothesis that there is a gradient of risk for postmenopausal obesity according to hormonal receptor status, at least for PR status, although this was not statistically significant.

Adult↗
PubMed2001

Endovascular treatment of transverse-sigmoid sinus dural arteriovenous malformations presenting as pulsatile tinnitus.

Transverse-sigmoid sinus dural arteriovenous malformations (DAVM) are uncommon vascular lesions for which complete cure may be difficult to obtain. A wide variety of treatments for these lesions include observation, arterial compression, surgical resection, and endovascular embolization. We propose that transverse-sigmoid sinus DAVM can be completely cured by occluding the ipsilateral dural sinus with detachable balloon and Guglielmi detachable coils (GDC) coils before arterial feeder embolization with histoacryl. Three patients who presented with pulsatile tinnitus and normal magnetic resonance imaging (MRI) studies underwent angiography, which demonstrated transverse-sigmoid sinus DAVM. All three patients wer treated with retrograde transvenous sinus embolization with complete occlusion of the transverse-sigmoid sinus with detachable balloons and GDC coils with preservation of the vein of Labbé. Subsequently, the various feeders from the external carotid artery were embolized. The tentorial arteries arising from the ipsilateral internal carotid arteries were not embolized in any of the cases, which were still contributing to the DAVM. Complete cure with thrombosis of the tentorial branch of the internal carotid artery (ICA) was seen on follow-up angiogram 1 day after embolization in one patient and on 4-week and 6-week follow-up angiograms in the other two patients. Complete occlusion of the transverse sinus proximal to the vein of Labbé, in spite of incomplete arterial feeder embolization, can result in complete cure of the transversesinus dural AVF if adequate time is given for the remaining feeders to occlude, once the fistula is obliterated.

Journal Article↗
PubMed2001

DDB2 induces nuclear accumulation of the hepatitis B virus X protein independently of binding to DDB1.

The hepatitis B virus (HBV) X protein (HBx) is critical for the life cycle of the virus. HBx associates with several host cell proteins including the DDB1 subunit of the damaged-DNA binding protein DDB. Recent studies on the X protein encoded by the woodchuck hepadnavirus have provided correlative evidence indicating that the interaction with DDB1 is important for establishment of infection by the virus. In addition, the interaction with DDB1 has been implicated in the nuclear localization of HBx. Because the DDB2 subunit of DDB is required for the nuclear accumulation of DDB1, we investigated the role of DDB2 in the nuclear accumulation of HBx. Here we show that expression of DDB2 increases the nuclear levels of HBx. Several C-terminal deletion mutants of DDB2 that fail to bind DDB1 are able to associate with HBx, suggesting that DDB2 may associate with HBx independently of binding to DDB1. We also show that DDB2 enhances the nuclear accumulation of HBx independently of binding to DDB1, since a mutant that does not bind DDB1 is able to enhance the nuclear accumulation of HBx. HBV infection is associated with liver pathogenesis. We show that the nuclear levels of DDB1 and DDB2 are tightly regulated in hepatocytes. Studies with regenerating mouse liver indicate that during late G1 phase the nuclear levels of both subunits of DDB are transiently increased, followed by a sharp decrease in S phase. Taken together, these results suggest that DDB1 and DDB2 would participate in the nuclear functions of HBx effectively only during the late-G1 phase of the cell cycle.

Cell Nucleus↗
PubMed2001

Atypical mouse cerebellar development is caused by ectopic expression of the forkhead box transcription factor HNF-3beta.

To assess the role of hepatocyte nuclear factor-3beta (HNF-3beta) in hepatocyte-specific gene transcription, we reported the characterization of the liver phenotype with transgenic mice in which the -3-kb transthyretin (TTR) promoter functioned to increase HNF-3beta expression. During breeding of the TTR-HNF-3beta transgenic mice we noticed that they displayed severe ataxia. In this study, we describe the analysis of our transgenic cerebellar phenotype and demonstrate that ectopic expression of HNF-3beta disrupted cerebellar morphogenesis and caused reduction in cerebellar size. In postnatal cerebellum, the HNF-3beta transgene expression pattern is colocalized to glial fibrillary acidic protein-positive cerebellar astrocytes and Bergmann glial cells. As a result of protracted expression, the transgenic cerebella are impaired in terms of astrocyte dispersal and formation of Bergmann glial cell processes. This caused a disruption in neuronal cell migration to the cortical laminar layers and Purkinje dendritic arbor maturation, thus leading to diminished foliation. Differential hybridization of cDNA arrays was used to identify altered expression of cerebellar genes, which is consistent with the observed defect in transgenic cerebellar morphogenesis and size as well as glial maturation. These include diminished expression of the brain lipid-binding protein, which is required for glial morphological differentiation, and the basic helix-loop-helix NeuroD/Beta2 and homeodomain Engrailed-2 transcription factors, which are required for normal cerebellar morphogenesis and foliation. Undetectable levels of ataxia telangiectasia (ATM), which is required for proper development of the Purkinje dendritic arbor, were found in postnatal transgenic cerebella. Furthermore, the transgenic cerebella displayed levels of insulin-like growth factor binding protein-1 elevated to 22 times greater than those measured for wild-type cerebella, an elevation consistent with the reduction in transgenic cerebellar size.

Animals↗
PubMed2000

Characteristics of lung cancer in Korea, 1997.

The high proportion of smokers and the incidence of advanced, unresectable lung cancer in Korea were examined to aid the development of a national anti-smoking program and the early detection of lung cancer. Koreans are a single racial group with a high smoking rate among men and a contrastingly low smoking rate among women. This report documents a retrospective investigation conducted by The Korean Academy of Tuberculosis and Respiratory Disease into the characteristics of all lung cancers diagnosed between 1 January 1997 and 31 December 1997 in Korea. Among the 3794 patients included in this study, 76.8% were smokers and, in particular, 89.8% of the males were smokers. Squamous cell carcinoma was the most frequent type of lung cancer encountered (44.7%), followed by adenocarcinoma (27.9%). The smoking rate in the case of adenocarcinoma was significantly lower than that found in both squamous cell carcinoma and small cell cancer. The most common symptom was a cough. Only 7.2% of patients were asymptomatic. Bronchoscopic biopsy has a primary role in the diagnosis of squamous cell carcinoma and small cell cancer, but percutaneous needle biopsy has a more important role in the case of adenocarcinoma. Two-thirds of the nonsmall cell lung cancer patients were detected in the unresectable advanced stages (IIIB and IV). In contrast to other countries, squamous cell carcinoma is still the most frequent type of lung cancer in Korea. The high proportion of smokers and the incidence of advanced, unresectable lung cancer at diagnosis have urged development of a national anti-smoking program to promote the cessation of smoking and the early detection of lung cancer.

Adult↗
PubMed2000

[Recurrence of cerebral aneurysms in the long-term follow-up after aneurysm surgery].

We investigated late aneurysmal recurrence in 71 patients who underwent direct operations for intracranial aneurysms during the period from 1981 to 1988 and were under 50 years old at the time of operation with ADL rating of 1 or 2 at discharge. And out of the 71 patients, four had already sustained reattack of SAH and been confirmed to have recurrent anuerysms. Another two had been diagnosed as harboring unruptured recurrent aneurysms. Cerebral angiography was carried out for nine patients in the remaining 63, revealing aneurysmal recurrence in four patients. Overall, 14 recurrent aneurysms, 11 de novo and 3 regrowth aneurysms, have been found in 10 patients. Considering the high risk of aneurysmal recurrence, postoperative long-term follow-up including MRA and angiography is mandatory, especially for relatively young patients.

Activities of Daily Living↗
PubMed1998

Prospective temporal analysis of the onset of preinfarction angina versus outcome: an ancillary study in TIMI-9B.

BACKGROUND: The timing of onset of angina before myocardial infarction in relation to outcome is unknown. METHODS AND RESULTS: We prospectively determined the importance of the time of onset of preinfarction angina in relation to 30-day outcomes in the TIMI-9B study from standardized forms. Of the 3002 patients entered into the study, 425 reported angina before their myocardial infarction. Patients with angina onset within 24 hours of infarction had a lower 30-day cardiac event rate (mortality, recurrent myocardial infarction, heart failure, or shock) at 4% than those with onset of angina >24 hours (17%; P=.030). A history of any angina alone was not associated with reduced event rate. Peak creatine kinase levels tended to be lower in the group with angina within 24 hours. These benefits were not due to higher rates of use of antianginal medicines or aspirin and were not a consequence of differences in baseline characteristics or disease states (hypertension, hypercholesterolemia) among subgroups. CONCLUSIONS: These temporal observations are consistent with the concept of preconditioning by preinfarction angina but do not rule out other mechanisms.

Aged↗
PubMed1998

Randomized, placebo-controlled study of tolcapone in patients with fluctuating Parkinson disease treated with levodopa-carbidopa. Tolcapone Fluctuator Study Group III.

OBJECTIVE: To assess the efficacy and tolerability of the catechol-O-methyltransferase inhibitor tolcapone in reducing "off/on" fluctuations in levodopa-treated parkinsonian patients. DESIGN: A randomized, double-blind, placebo-controlled, parallel-group study. SETTING: Fifteen Parkinson disease clinics. PATIENTS: Two hundred fifteen referred outpatients with Parkinson disease who showed predictable end-of-dose motor fluctuations that were not controlled by a stable levodopa-carbidopa (Sinemet) regimen of at least 4 weeks' duration. INTERVENTIONS: In addition to their usual levodopa-carbidopa regimen, patients received placebo or tolcapone, 100 or 200 mg, 3 times daily orally for 6 weeks. PRIMARY OUTCOME MEASURE: Change in daily off/on time. RESULTS: Tolcapone, 100 and 200 mg 3 times daily, reduced off time by 2.0 and 2.5 hours per day, respectively, and increased on time by 2.1 and 2.3 hours per day, respectively (P<.001 vs placebo). Investigators' global measures of disease severity indicated that significantly more tolcapone-treated patients had reduced wearing off and symptom severity (P<.001 vs placebo). No significant change in quality-of-life measures occurred. Clinical improvements occurred despite a reduction in total daily levodopa dose of 185.5 mg (23%) in the tolcapone, 100 mg 3 times daily, group and 251.5 mg (29%) in the 200 mg 3 times daily group. Principal adverse events (mainly dyskinesia and nausea) were levodopa related, were not treatment limiting, and were seldom reported as reasons for withdrawal. The frequency of withdrawals because of adverse events was similar in all groups (3% to 7%). CONCLUSIONS: Tolcapone was well tolerated and substantially increased on time and reduced off time in patients with fluctuating Parkinson disease. Additionally, levodopa requirements were significantly decreased.

Aged↗
PubMed1998

Familial cervical spondylosis. Case report.

Cervical spondylosis is a disease that is often attributed to aging and considered the result of degenerative changes in the spine. The idea that there is a genetic predisposition to develop diseases of the skeletal elements of the spine has been discussed previously, but has never been proven conclusively. The authors report three cases of severe cervical spondylosis in patients who are first-degree relatives: a mother and her two sons. All three individuals had cervical disc herniations and stenosis at C3-4, C4-5, C5-6, and C6-7, and all three required decompressive procedures. The location and degree of cervical spondylosis were as similar among these three patients as they have been in identical twins reported in other studies. Such familial inheritance of cervical spondylosis has been reported only once. The existence of familial cervical spondylosis is not an unrealistic proposal because other studies have shown that genetics determines the shape of one's spine and that similar spines tend to degenerate in similar ways. Therefore, genetic counseling for a family such as the one reported here may prove to be of great benefit to warn siblings that they are at high risk for cervical spine injury. However rare it might be, familial cervical spondylosis may be a phenomenon that any spine surgeon should suspect in a family with cervical spine abnormalities found in several members.

Adult↗
PubMed1997

An investigation of the safety of midazolam use in hospital.

OBJECTIVE: To investigate whether an association exists between midazolam use and serious cardiorespiratory events or death. DESIGN: Retrospective analysis of data in an inpatient record linkage database, collected between March 1986 and October 1987 from 14 hospitals in the United States. PATIENTS: A cohort of 19,112 patients who received injectable midazolam or diazepam on the same day that a medical procedure was performed. MAIN OUTCOME MEASURES: An attempt was made to identify suspected serious cardiorespiratory adverse events and deaths that occurred within 24 h of study-drug administration. Death rates within 24 h following study-drug administration were compared between patients who received injectable midazolam and those who received injectable diazepam. RESULTS: Validation analysis of the information in the computerized record linkage database indicated that serious cardiac and respiratory adverse events that occurred within 24 h of study-drug administration could not be reliably identified. Therefore, a comparison of the serious cardiorespiratory adverse event rates following administration of midazolam versus diazepam could not be made. Death rates within 24 h of study-drug administration could be evaluated. For the cohort as a whole, the death rate was significantly lower among patients who received midazolam than among those who received diazepam (0.76% versus 1.93%, p<0.01). This difference remained statistically significant, after adjusting for age, sex, comorbidity diagnosis, concomitant drug use, type of medical procedure, and hospital size and teaching capability. CONCLUSIONS: The results suggest that there is no increased risk of death associated with midazolam administration when compared to diazepam administration for endoscopic, conscious sedative, and general anesthetic procedures in hospitals.

Journal Article↗
PubMed1997

A high-risk group for prostatism: a population-based epidemiological study in Korea.

OBJECTIVE: To evaluate the effect of sociodemographic, dietary and physical factors on prostatism in Korean men aged 50 and over. SUBJECTS AND METHODS: A community-based cross-sectional epidemiological study was performed in Yonchon County, Korea. The Korean version of the International Prostate Symptom Score (IPSS) was used to assess the severity of prostatism. Data on occupation, marital status, education, smoking habits, alcohol intake, daily consumption of nutrients, body mass index, abdominal circumference, waist-to-hip ratio, blood pressure, serum glucose, cholesterol, triglyceride and high-density lipoprotein (HDL) levels were analysed. The age-adjusted relative risk of these factors was calculated for moderate to severe prostatism (IPSS > or = 8). A multivariate analysis of all significant factors was performed to examine the joint effect of risk factors. RESULTS: Of 514 subjects, 119 (23.2%) had moderate to severe prostatism, the risk for which was related to age and alcohol consumption; waist-to-hip ratio (which represents the degree of abdominal obesity) and the serum level of HDL showed a biphasic association with prostatism in the multivariate analysis. CONCLUSION: In addition to previously reported risk factors, these data suggest that there might be an association between the development of prostatism and abnormal lipid metabolism.

Age Factors↗
PubMed1997

Tolcapone improves motor function and reduces levodopa requirement in patients with Parkinson's disease experiencing motor fluctuations: a multicenter, double-blind, randomized, placebo-controlled trial. Tolcapone Fluctuator Study Group I.

Tolcapone is a potent catechol-O-methyltransferase inhibitor that prolongs the plasma half-life of levodopa. This multicenter, double-blind, placebo-controlled study used two 10-hour clinical evaluations to compare the efficacy and safety of three doses of tolcapone (50, 200, and 400 mg tid) with placebo in patients with Parkinson's disease (PD) experiencing motor fluctuations from levodopa/carbidopa. One hundred fifty-one patients completed the study. Clinical evaluations lasting 10 hours were performed on day -1 and day 42 using United Parkinson's Disease Rating Scale motor subscale and "on/off" and dyskinesia assessments every 30 minutes. Tolcapone significantly reduced "off" time an average of 40% and increased total "on" time by about 25% at all dose levels, as compared to placebo treatment. Levodopa/carbidopa dosage and frequency were significantly reduced. Tolcapone was well tolerated, with patients experiencing typical dopaminergic side effects that could be reduced or eliminated by lowering levodopa/carbidopa dosages. Tolcapone was effective at prolonging the clinical benefit of levodopa and reducing total levodopa requirements in PD patients with motor fluctuations.

Aged↗
PubMed1997

Changes of the plasma endothelin in adaptation to increased salt intake in rats.

OBJECTIVES: Roles for vascular endothelial hormones in body fluid balance have been variously suggested. The present study was aimed at investigating whether the plasma endothelin is altered in responses to acute and chronic perturbations in body fluid balance. METHODS: Effects of intravenous infusion of MG-nitro-L-arginine methyl ester (L-NAME), a competitive inhibitor of endothelium-derived nitric oxide (NO) synthesis, on urinary excretion, blood pressure and plasma levels of endothelin were examined in rats kept on either normal or high-salt diet for two weeks. The plasma endothelin levels in response to an acute extracellular volume expansion (VE) were also determined in normal and 2-kidney, 1 clip (2K1C) hypertensive rats. RESULTS: L-NAME (20 and 200 micrograms.kg(-1) per min) elicited diuretic and natriuretic effects in association with increased blood pressure both in normal and high-salt rats. In high-salt rats, however, the urinary response to L-NAME was attenuated and the pressor response was augmented compared with the control. High-salt intake per se caused a small, but significant, increase of the plasma endothelin. L-NAME (200 micrograms(-1) per min) markedly increased the plasma endothelin was also marginally increased following VE, the magnitude of which did not differ between the normal and 2K1C rats. CONCLUSION: These results suggest that the endothelin system takes part in adaptation to increased salt-intake. Another evidence indicating a negative modulation of NO on the release of endothelin is also provided.

Adaptation, Physiological↗