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Biomedical subjects

D S Kim

Publications and source records attributed to D S Kim.

At least 55 records · Page 3Linked to original sources
PubMed2003

Infection, allergy and the hygiene hypothesis: historical perspective.

The 'hygiene hypothesis' was popularized in the late 1980s to explain the high prevalence of atopic disorders in the developed countries. It links atopic disorders and the lack of early life infections. An association between the two is not novel and dates back to the beginnings of allergy, immunology and microbiology. Allergy and infection have always been closely related and the study of one has often provided new insights into the pathobiology of the other. Early research into bacterial infections led to the discovery of the human immune system and the concept of allergy. An important relationship exists between parasite infections and the development of atopic disorders. This review traces the long and intimate historical relationship between infection and allergy.

Antigens, Bacterial↗
PubMed2002

Quantum interference of virtual and real amplitudes in a semiconductor exciton system.

By two-color pulse shaping, we simultaneously create virtual and real amplitudes for excitons in GaAs quantum wells, and monitor population and amplitude by pump-probe and four-wave mixing spectroscopies. Excited-state probability amplitude can be induced by the off-resonant, virtual excitations as well as by the resonant, real excitations. Population modulation in time-domain results from the interference between the virtual and real amplitudes, and the modulation depth reveals the relative contributions of these two amplitudes. The fact that virtual and real amplitudes have a phase difference of 90 degrees is demonstrated directly in time-domain.

Journal Article↗
PubMed2002

Postexercise facilitation of reflexes is not common in Lambert-Eaton myasthenic syndrome.

Postexercise facilitation (PEF) with clinical reflexes, H-reflex, and T-reflexes at the ankle and knee was systematically studied in 16 patients with Lambert-Eaton myasthenic syndrome (LEMS). PEF was observed in ankle and knee deep tendon reflexes in five patients, in H-reflex in three patients, and in T-reflexes in six patients. When all reflex tests were combined, 7 (43.7%) of 16 patients showed PEF by at least one test. The authors conclude that the PEF of reflexes, the most helpful diagnostic clinical marker for LEMS, is not common.

Adult↗
PubMed2002

Coherent optical phonon oscillations in bulk GaN excited by far below the band gap photons.

We report on generation of coherent optical phonon oscillations in 150 microm thick bulk GaN. With photon energy far below the band gap, the generation mechanisms of coherent phonon modes of A1(LO), high- and low-frequency E2 are revealed to be the impulsive stimulated Raman scattering. We find that one among the two degenerate E2 modes is selectively detected with a proper choice of probe polarization. Dephasing times range from 1.5 to 70 ps for different modes, and phonon-three-photon absorbed carrier interactions are compared between the A1(LO) and the E2 mode.

Journal Article↗
PubMed2002

Significance of temperature difference between cerebral cortex and axilla in patients under hypothermia management.

It is believed that the brain temperature is about 1 degree C higher than the other peripheral temperature. But the result has been mostly obtained in normothermia patients. The objective of this study was to evaluate whether the brain temperature is still higher than the axillary one in the hypothermia patients. Sixty-three patients who underwent craniotomy with implantation of the thermal diffusion thermometer were included in this study. Fifty-four patients were in normothermia and nine patients were managed with mild to moderate hypothermia (about 32 degrees C). The temperature of the cerebral cortex and axilla was measured simultaneously every 2 hours. 1900 paired sample data were collected and analyzed. The temperature difference between the cerebral cortex and the axilla was 1.04 +/- 0.67 degrees C in normothermia patients and 0.91 +/- 0.84 degree C in hypothermic patients. The temperature difference has no statistical significance between the two groups (unpaired t-test, P > 0.05). Our results demonstrate that the brain temperature in the patients under hypothermia management appears to be still about 1 degree C higher than the axilla throughout the study period almost in the same fashion as in normothermia patients.

Adolescent↗
PubMed2002

PCR-RFLP based molecular typing of enteroviruses isolated from patients with aseptic meningitis in Korea.

We have evaluated PCR-RFLP as a practical method for rapid typing of enteroviruses causing aseptic meningitis in Korea. Through blind examination of 80 clinical isolates from patients with aseptic meningitis, we have compared the results of conventional serotyping with PCR-RFLP based genotyping, which was developed for this study. Among the 80 case isolates, which had been previously typed by routine neutralization test, only 42 cases (52.5%) were matched with typing by PCR-RFLP. The result clearly demonstrated that the enterovirus serotype does not coincide with the genotype. Therefore, the classification of enteroviruses by genotyping with PCR-RFLP, although rapid and simple, may be complicated by regional or seasonal differences. However, the PCR-RFLP method developed in this study is applicable to the epidemiological study of enteroviruses when regional or seasonal differences exist, and is useful in identifying the source of an infection.

Enterovirus↗
PubMed2002

The intracellular pathway of the acetylcholine-induced contraction in cat detrusor muscle cells.

1. The present study was aimed to investigate intracellular pathways involved in acetylcholine (ACh)-induced contraction in cat detrusor muscle cells 2. Contraction was expressed as per cent shortening of length of individually isolated smooth muscle cells obtained by enzymatic digestion. Dispersed intact and permeabilized cells were prepared for the treatment of drugs and antibody to enzymes, respectively. Using Western blot, we confirmed the presence of related proteins. 3. The maximal contraction to ACh was generated at 10(-11) M. This response was preferentially antagonized by M3 muscarinic receptor antagonist rho-fluoro-hexahydrosiladifenidol (rhoF-HSD) but not by the M1 antagonist pirenzepine and the M2 muscarinic receptor antagonist methoctramine. We identified G-proteins (Gq/11), (Gs), (G0), (Gi1), (Gi2) and (Gi3) in the bladder detrusor muscle. ACh-induced contraction was selectively inhibited by (Gq/11) antibody but not to other G subunit. 4. The phosphatidylinositol-specific phospholipase C (PI-PLC) inhibitor neomycin reduced ACh-induced contraction. However, the inhibitors of the phospholipase D, the phospholipase A2 and protein kinase C did not attenuate the ACh-induced contraction. ACh-induced contraction was inhibited by antibody to PLC-beta1 but not PLC-beta3 and PLC-gamma. Thapsigargin or strontium, which depletes or blocks intracellular calcium release, inhibited ACh-induced contraction. Inositol 1,4,5-triphosphate IP3 receptor inhibitor heparin reduced ACh-induced contraction. 5. These results suggest that in cat detrusor muscle contraction induced by ACh is mediated via M3 muscarinic receptor-dependent activation of Gq/11 and PLC-beta1 and IP3-dependent Ca(2+) release.

Acetylcholine↗
PubMed2002

Extraordinarily high rates of male circumcision in South Korea: history and underlying causes.

OBJECTIVE: To investigate the high circumcision rate in South Korea and its rapid increase in the short period since its introduction. SUBJECTS AND METHODS: From January to December 2000, 5434 South Korean males (or their parents) aged 0-92 years were interviewed in detail about their circumcision status, their age at circumcision, and the possible effect of circumcision on their sexuality. In addition, 267 practising medical doctors were surveyed about their basic understanding of circumcision and phimosis. RESULTS: Currently the circumcision rate for high-school boys is > 90% and for those > 70 years old is < 10%. The circumcision rate in 1945 was < 0.1%. When averaged over the whole population, the present South Korean circumcision rate is approximately 60%; the rate has increased dramatically with time and particularly in the past 20 years, when the estimated number of male circumcisions has exceeded the number of male births. Although circumcision in South Korea has been strongly influenced by American culture, it has never been predominantly neonatal. The age at circumcision has continued to decrease and boys are now circumcised at approximately 12 years old. Of those who were circumcised long after they had been sexually active, > 80% reported no noticeable difference in sexuality, but a man was twice as likely to have experienced diminished sexuality than improved sexuality. Of the doctors who were surveyed, 41% carried out circumcision but, unlike in America, gynaecologists and paediatricians rarely did so. Among the doctors, basic knowledge on circumcision and phimosis was generally lacking, regardless of whether they practised circumcision or not. Amongst the factors contributing to the high circumcision rate was the mistaken notion held by both doctors and the general public that circumcision is directly correlated with industrialization and general progress of living standards. Many doctors believe the out-dated and sometimes controversial benefits of circumcision, i.e. prevention of cervical cancer and sexually transmitted diseases, and improved sexuality. Thus the vast majority of doctors recommend circumcision regardless of the patient's age. Peer pressure was also an important contributing factor. CONCLUSION: South Korea has an unusual history of circumcision. The mistaken and out-dated notions about circumcision and lack of knowledge of phimosis by physicians seem to be a leading contributory factor to the extraordinarily high circumcision rate.

Adolescent↗
PubMed2001

Changes in voltage-gated calcium channel alpha(1) gene expression in rat dorsal root ganglia following peripheral nerve injury.

Although an increase in the excitability and ectopic spontaneous discharge (ESD) of primary sensory neurons can lead to abnormal burst activity, which is associated with neuropathic pain, the underlying molecular mechanisms are not fully understood. To investigate the relationship between these electrical abnormalities in injured neurons and voltage-gated calcium channel (VGCC) gene expression, reverse transcription-polymerase chain reaction (RT-PCR) was used to monitor the expression of the VGCC alpha(1) gene in the dorsal root ganglion (DRG) following chronic constriction injury (CCI) and axotomy of the rat sciatic nerve. Electrophoresis of the RT-PCR products showed the presence of multiple types of VGCC alpha(1) transcripts with various levels of basal expression in lumbar 4, 5, and 6 DRGs. CCI decreased alpha(1C), alpha(1D), alpha(1H), and alpha(1I) mRNA expression at 7 days in the ipsilateral DRG, to approximately 34-50% of the contralateral side. The same transcripts were repressed 7 days after sciatic axotomy and their reduction levels proved similar to those of CCI. Considering that changes of the intracellular calcium concentration modify the maintenance of ESD in injured DRG, these results suggest that the downregulation of alpha(1C), alpha(1D), alpha(1H) and alpha(1I) subunit gene expression in the rat DRG following peripheral nerve injury may contribute to the production of ESD associated with damaged nerves.

Animals↗
PubMed2001

Vascular effects of estrogen in type II diabetic postmenopausal women.

OBJECTIVES: We assessed the effects of estrogen on vascular dilatory and other homeostatic functions potentially affected by nitric oxide (NO)-potentiating properties in type II diabetic postmenopausal women. BACKGROUND: There is a higher cardiovascular risk in diabetic women than in nondiabetic women. This would suggest that women with diabetes do not have the cardioprotection associated with estrogen. METHODS: We administered placebo or conjugated equine estrogen, 0.625 mg/day for 8 weeks, to 20 type II diabetic postmenopausal women in a randomized, double-blinded, placebo-controlled, cross-over design. RESULTS: Compared with placebo, estrogen tended to lower low-density lipoprotein (LDL) cholesterol levels by 15 +/- 23% (p = 0.007) and increase high-density lipoprotein (HDL) cholesterol levels by 8 +/- 16% (p = 0.034). Thus, the ratio of LDL to HDL cholesterol levels significantly decreased with estrogen, by 20 +/- 24%, as compared with placebo (p = 0.001). Compared with placebo, estrogen tended to increase triglyceride levels by 16 +/- 48% and lower glycosylated hemoglobin levels by 3 +/- 13% (p = 0.295 and p = 0.199, respectively). However, estrogen did not significantly improve the percent flow-mediated dilatory response to hyperemia (17 +/- 75% vs. placebo; p = 0.501). The statistical power to accept our observation was 81.5%. Compared with placebo, estrogen did not significantly change E-selectin, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, monocyte chemoattractant protein-1 or matrix metalloproteinase-9 levels. Compared with placebo, estrogen tended to decrease tissue factor antigen and increase tissue factor activity levels by 7 +/- 46% and 5 +/- 34%, respectively (p = 0.321 and p = 0.117, respectively) and lower plasminogen activator inhibitor-1 levels by 16 +/- 31% (p = 0.043). CONCLUSIONS: The effects of estrogen on endothelial, vascular dilatory and other homeostatic functions were less apparent in type II diabetic postmenopausal women, despite the beneficial effects of estrogen on lipoprotein levels.

Brachial Artery↗
PubMed2001

The induction of BDNF and c-fos mRNA in the hippocampal formation after febrile seizures.

In this study we investigated the expression of brain-derived neurotrophic factor (BDNF) and c-fos mRNA in the hippocampal formation after febrile seizures (FSs) with in situ hybridization histochemistry using riboprobes. The induction of BDNF mRNA was firstly observed in the dentate gyrus at 30 min after FSs. The expression in the dentate gyrus peaked at 3 h and returned to basal level at 24 h. It was also observed in the CA3 of hippocampus from 2 to 3 h. The induction of c-fos mRNA was observed in the dentate gyrus at 30 min and 1 h. These observations suggest that BDNF and c-fos are the genes whose expression can be altered by FSs and might be related to pathologic alterations after FSs.

Animals↗
PubMed2001

Differentially expressed genes in rat dorsal root ganglia following peripheral nerve injury.

Ordered differential display PCR was used to identify differentially expressed genes in rat dorsal root ganglia at 7 days following chronic constriction injury (CCI) of the sciatic nerve. Fourteen differentially displayed cDNA bands were isolated, cloned and verified by RT-PCR. The four mRNAs were increased, which included mRNAs encoding heat shock protein 27, fatty acid binding protein, apolipoprotein D and one novel gene. Six down-regulated clones were microtubule-associated protein 1B, protein tyrosine phosphatase alpha, Kv1.2 channel, myelin protein SR13, medium-sized neurofilament protein, and one novel gene. Our results show that many differentially regulated genes after CCI may play a role in nerve degeneration and/or regeneration and provide a molecular framework for understanding the peripheral mechanism underlying neuropathic pain.

Animals↗
PubMed2001

Suppression of tumorigenicity and metastasis in B16F10 cells by PTEN/MMAC1/TEP1 gene.

PTEN/MMAC1/TEP1 (PTEN) is a tumor suppressor gene that is mutated in a variety of advanced and metastatic cancers, strongly suggests that PTEN alteration is possibly involved in the tumor progression and formation of metastases. However, the roles of PTEN in tumor growth and metastasis and its functional mechanisms are not fully understood. We evaluated the tumor suppressor function of PTEN gene on tumor growth and metastasis in vitro and in vivo. Our results of in vitro soft agar assay and in vivo PTEN-expressing tumor cell growth showed that PTEN inhibited the tumorigenicity of B16F10 melanoma cells. Anti-metastatic function of PTEN was also revealed by experimental pulmonary metastatic animal model. For the further insight into the mechanisms underlying the PTEN-mediated inhibition of tumor metastasis, we have examined the role of PTEN on the secretion of matrix metalloproteinases (MMPs), insulin-like growth factors (IGFs) and the expression of secretory and cellular vascular endothelial growth factor (VEGF) proteins that have been described to contribute to the metastasis of tumor. PTEN significantly lowered MMPs and IGFs secretion and also expression of secretory and cellular VEGF proteins. These results suggest that PTEN tumor suppressor protein inhibits tumorigenicity and metastasis through regulation of MMP, IGFs, and VEGF expression.

Animals↗
PubMed2001

Pathogenic role of endothelin 1 in hemodynamic dysfunction in experimental acute pulmonary thromboembolism.

The plasma endothelin-1 (ET-1) level is elevated in patients with acute pulmonary thromboembolism (APE). Whether ET-1 is a pathogenic mediator or a simple marker of APE is not known. We investigated the role of ET-1 in hemodynamic dysfunction in APE through evaluating the effects of ET(A) receptor antagonist in an experimental APE model. We also examined ET-1 expression in embolized lungs. In a canine autologous blood clot pulmonary embolism model, ET(A) receptor antagonist ZD2574 (10 mg/kg, intravenous; ZD2574 group; n = 6) or vehicle (control group; n = 5) was administered. Hemodynamic and gas exchange parameters and plasma levels of ET-1 were serially measured. Prepro-ET-1 mRNA expression and the distribution of ET-1 peptide in lung tissues were also examined. With ZD2574 pulmonary arterial pressure and pulmonary vascular resistance significantly decreased, and were lower compared with the control group. The decrease in cardiac output was also less in the ZD2574 group. Plasma ET-1 levels increased after embolization. Prepro-ET-1 mRNA expression increased in embolized lungs and ET-1 peptide expression also increased in embolized lungs, particularly in the muscular pulmonary arteries, compared with normal lungs. These findings suggest that ET-1 partially contributes to hemodynamic derangements of APE, and that ET(A) receptor antagonists might constitute a useful therapeutic tool for APE.

Acute Disease↗
PubMed2001

Total synthesis of Calebin-A, preparation of its analogues, and their neuronal cell protectivity against beta-amyloid insult.

A total synthesis of Calebin-A (1), a novel curcuminoid isolated from turmeric (Curcuma longa, Zingiberaceae) that has been demonstrated to protect neuronal cells from beta-amyloid insult, was successfully achieved in four steps. Elaborating on this synthetic route, 13 analogues were prepared for a structure-activity relationship (SAR) study. It was found that the parent compound 1 and derivatives 21, 28, and 30 protect PC12 rat pheocromocytoma and IMR-32 human neuroblastoma cells from beta-amyloid(25-35) insult. These results suggest that hydroxy group at para-position is most critical for the expression of biological activity.

Amyloid beta-Peptides↗