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Biomedical subjects

H S Yu

Publications and source records attributed to H S Yu.

At least 37 records · Page 2Linked to original sources
PubMed2000

Cutaneous blood flow and adrenoceptor response increase in segmental-type vitiligo lesions.

It has been proposed that two types of vitiligo exist from the physiological and clinical points of view. Nonsegmental-type vitiligo is associated with autoimmune diseases while segmental-type vitiligo results from the dysfunction of sympathetic nerves in the affected area. Using laser Doppler flowmetry and iontophoresis for cutaneous microcirculatory assessments, we evaluated these two types of vitiligo in regard to their physiological changes. Ten patients with facial stable stage segmental-type vitiligo and ten stable nonsegmental-type vitiligo patients were selected for this study. Our results revealed that a nearly threefold increase in cutaneous blood flow was noticed in segmental-type vitiligo as compared to contralateral normal skin. In contrast, a 1.4-1.5 times difference was found among nonsegmental-type vitiligo, lesion side clinically normal skin and contralateral normal skin. There was a significant increase in cutaneous alpha- and beta-adrenoceptor response in segmental-type vitiligo lesions. However, no change in plasma catecholamines or adrenoceptor densities on blood cells was noticed. Our findings suggest that a dysfunction of the sympathetic nerves exists in the affected skin and plays a role in the pathogenesis of segmental-type vitiligo.

Adolescent↗
PubMed2000

IgG anti-melanocyte antibodies purified from patients with active vitiligo induce HLA-DR and intercellular adhesion molecule-1 expression and an increase in interleukin-8 release by melanocytes.

An immunologic hypothesis is currently proposed as a possible pathogenesis of nonsegmental-type vitiligo. IgG antibodies against melanocyte surface antigens exist in the serum of patients with vitiligo vulgaris. IgG anti-melanocyte antibodies were reported to induce melanocyte damage in vitro by a complement-mediated mechanism and antibody-dependent cellular cytotoxicity. Perilesional melanocytes express major histocompatibility complex class II antigens and a higher intercellular adhesion molecule-1 compared with those in normal skin. The purpose of this study was to determine the role of IgG anti-melanocyte antibodies in the inappropriate expression of major histocompatibility complex class II antigens and intercellular adhesion molecule-1 on melanocytes. IgG anti-melanocyte antibody samples were purified from the individual serum of patients with active vitiligo. After incubation of IgG anti-melanocyte antibodies with cultured melanocytes, the results revealed: (i) IgG anti-melanocyte antibody stimulated HLA-DR expression on melanocytes; (ii) intercellular adhesion molecule-1 expression on melanocytes was significantly induced by IgG anti-melanocyte antibodies; and (iii) IgG anti-melanocyte antibodies induced an increase in interleukin-8 release from melanocytes. The major histocompatibility complex class II molecules expressed in melanocytes can present antigens to CD4 helper cells as antigen-presenting cells and elicit an immune response. Intercellular adhesion molecule-1 is an important adhesion molecule involved in leukocyte and parenchymal cell interaction and thus plays an essential part in immunologic and inflammatory reactions. It is reasonable to speculate that abnormal expressions of HLA-DR and intercellular adhesion molecule-1 on melanocytes by IgG anti-melanocyte antibodies would present vitiligo antigens and allow the antigen-specific immune effector cell attack that results in melanocytotoxicity.

Antibodies, Anti-Idiotypic↗
PubMed2000

Antiepiligrin cicatricial pemphigoid.

Cicatricial pemphigoid is a chronic subepithelial autoimmune blistering disease of mucous membranes and skin. Recently, a subtype of cicatricial pemphigoid with autoantibodies to epiligrin was identified. We describe a Taiwanese patient who presented with ocular, oral, and cutaneous involvement. Direct immunofluorescence showed IgG and C3 deposition in epidermal basement membrane; indirect immunofluorescence showed circulating IgG autoantibodies reactive with the dermal side of 1 mol/L sodium chloride-split skin. Immunoblotting of laminin 5 isolated from the extracellular matrix of cultured human keratinocytes showed no specific reactivity. In contrast, with immunoprecipitation of the conditioned culture media from biosynthetically radiolabeled human keratinocytes, this patient's serum clearly reacted with a series of disulfide-linked polypeptides that correspond to laminin 5(alpha3beta3gamma2) and laminin 6(alpha3beta1gamma1). This is the first confirmed case of a patient of Chinese ancestry with this disease entity.

Aged↗
PubMed2000

Interleukin-8 secretion by cultured oral epidermoid carcinoma cells induced with nicotine and/or arecoline treatments.

Interleukin-8 (IL-8) is one of the multifunctional cytokines that can play a role on immune and inflammatory activities. Other in vitro observations indicated that IL-8 is a growth factor for keratinocytes. However, as the role of IL-8 in oral cancer cells is unclear, this study is thus designed to examine IL-8 secretion in cultured oral epidermoid carcinoma KB CCL17 cells treated with nicotine and/or arecoline. The cultures were treated with nicotine (1 or 100 microM) and arecoline (1 or 100 microM), alone or both, for 72 hrs. Enzyme-linked immunosorbent assay (ELISA) was used to examine IL-8 concentrations in culture supernatants. A repeated measure analysis of variance was used to identify differences among the treatments. Nicotine and arecoline, single or combined treatment, increased IL-8 secretion in KB CCL17 cells. When monoclonal 1 microgram/ml of antibody was added against IL-1 alpha or IL-1 beta in the treatment, IL-8 concentration significantly decreased compared with the non-added one. Exposure of cells to antibody against IL-1 alpha or IL-1 beta showed no significant increase in cell growth as compared with the control (medium alone). However, incubation of cells for 72 hrs in the presence of nicotine and/or arecoline treatments and antibody against IL-1 alpha or IL-1 beta significantly increased cell growth as compared with the antibody free one. It was concluded that IL-8 secretion by KB CCL17 cells may be partially mediated by IL-1 which could inhibit the KB CCL17 cell growth. Thus, IL-8 may be a vital participant in the cascade of interacting cytokines during smoking and areca quid chewing, inducing inflammation in oral cancer.

Antibodies, Monoclonal↗
PubMed1999

Increased cutaneous blood flow but impaired post-ischemic response of nutritional flow in obese children.

It is well known that cardiovascular risk factors and dyslipidemia along with obesity can be identified early in life. Serum lipids and lipoproteins influence skin vessel reactivity in adults. The purpose of this study was to investigate the cutaneous microcirculation and its correlation to dyslipidemia in obese children. Thirty-four obese children and an equal number of age- and sex-matched healthy children were enrolled in this study. Laser Doppler flowmetry and dynamic capillaroscopy were performed to measure total cutaneous blood flow and nutritional blood flow, respectively. A significantly higher cutaneous baseline flow and peak flow after a 1-min arterial occlusion was noticed in obese group as compared to normal control. Results of dynamic capillaroscopy revealed values of resting capillary blood cell velocity that did not differ from controls but a significantly lower peak CBV after a 1-min arterial occlusion in obesity. Plasma lipids examination showed a high triglycerides and low high density lipoprotein cholesterol levels in obesity. Pearson analysis detected no significant correlations between pCBV, baseline flow and peak flow and dyslipidemia in obesity. These results may be explained by the fact that the duration of dyslipidemia in our study population was not long enough to cause vascular damage or the dyslipidemia was not pronounced enough to have an impact on skin vessel activity tests. It is also possible, that the combination of methods used in the present study was not sensitive enough to detect an existing correlations between flow values and high triglycerides/low HDL-cholesterol values in the obese group. Our results suggest that all the responses of the cutaneous microcirculation were mainly due to physiological compensatory rather than pathological reactions in young obese children. The results of cutaneous microcirculatory assessment in obese children provide follow-up parameters for assessing the risk of cardiovascular diseases later in life.

Adolescent↗
PubMed1999

Mutational spectrum of p53 gene in arsenic-related skin cancers from the blackfoot disease endemic area of Taiwan.

To understand the role of p53 tumour suppressor gene in the carcinogenesis of arsenic-related skin cancers from the blackfoot disease endemic area of Taiwan, we collected tumour samples from 23 patients with Bowen's disease, seven patients with basal cell carcinomas (BCC) and nine patients with squamous cell carcinomas (SCC). The result showed that p53 gene mutations were found in 39% of cases with Bowen's disease (9/23), 28.6% of cases with BCC (2/7) and 55.6% of cases with SCC (5/9). Most of the mutation sites were located on exon 5 and exon 8. Moreover, the results from direct sequencing indicated that missense mutations were found at codon 149 (C-->T) in one case, codon 175 (G-->A) in three cases, codon 273 (G-->C) in three cases, codon 292 (T-->A) in one case, codon 283 (G-->T) in one case, codon 172 (T-->C) in one case and codon 284 (C-->A) in one case. In addition, silent mutations were also found in four cases. These mutations were located at codons 174, 253, 289 and 298 respectively. In immunohistochemistry analysis, p53 overexpression was found in 43.5% (10/23) of cases with Bowen's disease, 14% (1/7) of cases with BCC and 44% (4/9) of cases with SSC. These findings showed that p53 gene mutation rate in arsenic-related skin cancers from the blackfoot disease endemic area of Taiwan is high and that the mutation types are different from those in UV-induced skin cancers.

Aged↗
PubMed1999

Ethnic dental analysis of shovel and Carabelli's traits in a Chinese population.

Chinese populations differ from Caucasoids by having a high prevalence of shovel trait and a low prevalence of Carabelli's trait. This study was conducted to investigate the association between the shovel and the Carabelli's traits in a Chinese population. The research design investigated a Chinese population that resides in southern Taiwan. The ancestors of this Chinese population migrated to Taiwan from mainland China, mainly from Fukien and Kwangtung. The effects of sex and age on Carabelli's trait were controlled in this investigation, as was the association between tooth size and Carabelli's trait. Results show that males were more likely to have Carabelli's trait expressed on teeth than females. The buccolingual diameter of Carabelli's trait teeth was larger than that of teeth without the trait. After controlling for sex, age, and tooth size, the existence of the shovel trait increased the likelihood of having Carabelli's trait by a factor of five and a half, which is a significant effect.

Adolescent↗
PubMed1999

Phylogenetic relationships among Acanthamoeba spp. based on PCR-RFLP analyses of mitochondrial small subunit rRNA gene.

We investigated the value of mitochondrial small subunit rRNA gene (mt SSU rDNA) PCR-RFLP as a taxonomic tool for Acanthamoeba isolates with close inter-relationships. Twenty-five isolates representing 20 species were included in the analysis. As in nuclear 18S rDNA analysis, two type strains (A. astronyxis and A. tubiashi) of morphological group 1 diverged earliest from the other strains, but the divergence between them was less than in 18S riboprinting. Acanthamoeba griffini of morphological group 2 branched between pathogenic (A. culbertsoni A-1 and A. healyi OC-3A) and nonpathogenic (A. palestinensis Reich, A. pustulosa GE-3a, A. royreba Oak Ridge, and A lenticulata PD2S) strains of morphological group 3. Among the remaining isolates of morphological group 2, the Chang strain had the identical mitochondrial riboprints as the type strain of A. hatchetti. AA2 and AA1, the type strains of A. divionensis and A. paradivionensis, respectively, had the identical riboprints as A. quina Vil3 and A. castellanii Ma. Although the branching orders of A. castellanii Neff, A. polyphaga P23, A. triangularis SH621, and A. lugdunensis L3a were different from those in 18S riboprinting analysis, the results obtained from this study generally coincided well with those from 18S riboprinting. Mitochondrial riboprinting may have an advantage over nuclear 18S rDNA riboprinting because the mt SSU rDNAs do not seem to have introns that are found in the 18S genes of Acanthamoeba and that distort phylogenetic analyses.

Acanthamoeba↗
PubMed1998

Acupuncture treatment of urticaria.

Acupuncture has long been used to treat urticaria in the Asian world. Acute urticaria can be easily and effectively treated with acupuncture. L111 (Quchi), Sp10 (Xuehai), Sp6 (Sanyinjiao), and S36 (Zusanli) are the 4 acupuncture points most commonly prescribed. Chronic urticaria is a challenge for medical therapy. There are at least 6 kinds of acupuncture methods developed to overcome this challenge. The combination of ordinary acupuncture and auricular acupuncture has been observed to be a highly effective cure of chronic urticaria. Acupuncture point injection with thiamine hydrochloride (vitamin B1) is also an effective treatment. However, results of these clinical observations have not been systematically confirmed for lack of a control group and the need for standard classification of urticaria. Although these observational results have clinical limitations, they do offer insight into an alternative to conventional treatment of urticaria. In the future, acupuncture or acupuncturelike techniques may provide an effective alternative for treatment of patients with urticaria, particularly those refractory to medication therapy.

Acupuncture Therapy↗
PubMed1998

Interleukin-13 increases prostaglandin E2 (PGE2) production by normal human polymorphonuclear neutrophils by enhancing cyclooxygenase 2 (COX-2) gene expression.

OBJECTIVE: To investigate whether interleukin-13 (IL-13) can affect arachidonic acid metabolism and phagocytic activity of normal human polymorphonuclear neutrophils (PMN). METHODS: Normal human PMN (1 x 10(6) cells/ml) were incubated with different concentrations of IL-13 (0.1-10 ng/ml) for a variety of times (30-120 min). Phagocytosis and intracellular cyclooxygenase-2 (COX-2) were detected by flow cytometry. The expression of COX-1 and COX-2 mRNA was detected by RT-PCR. The concentration of PGE2 in the PMN cultured supernatants was determined by EIA. RESULTS: We found that IL-13 at an optimal concentration of 1 ng/ml significantly enhanced COX-2 gene expression and PGE2 production (121.57 +/- 22.17 pg/ml in IL-13 stimulation vs. 73.16 +/- 11.72 pg/ml in controls) by PMN. In addition, IL-13 stimulated PMN phagocytosis via increased complement receptor type 1 (CR1) and type 3 (CR3), but not IgG Fcgamma receptor type 3 (FcgammaRIII). The cytoplasmic neutral esterase activity of PMN was also enhanced by IL-13 stimulation for 24 h. CONCLUSIONS: These results suggest that IL-13 can stimulate PMN and modulates the inflammatory reactions via the cyclooxygenase pathway.

Cells, Cultured↗
PubMed1998

Defective IL-2 receptor expression in lymphocytes of patients with arsenic-induced Bowen's disease.

The immune function of peripheral mononuclear cells (MNC) in patients with endemic arsenic-induced Bowen's disease (BD) was investigated. Many cytokines and immune-related factors were determined in the present study. Interleukin-1beta and TNF-alpha production was used as an indicator of monocyte/macrophage function. II-2 and sIL-2R production was used as an indicator of lymphocyte activation. The release of sCD4 and sCD8 was used as an indicator of activation of respective T-cell subpopulations. Production of IFN-gamma and IL-2 reflected the cellular effector function of helper T-cells type 1. In vivo cell-mediated immunity was also assessed by estimation of the percentage of T-cells in peripheral blood MNC and the nonspecific delayed-type hypersensitivity (DTH) response to 2,4-dinitrochlorobenzene (DNCB). Both assays revealed depressed cell-mediated immunity in BD. Compared with healthy controls, spontaneous and PHA-induced IFN-gamma and TNF-alpha production was significantly decreased in BD whereas spontaneous release of IL-2, sCD4 and sCD8 was significantly increased. Although PHA stimulation increased IL-2 release, the expression of IL-2R alpha and beta chains and the release of sIL-2R were not proportionately increased in BD. In addition, IL-2-mediated [3H]-thymidine incorporation by MNC in patients with BD was significantly decreased. These findings suggest that the defective cell-mediated immune function in BD is due to impairment of membrane IL-2R expression in lymphocytes after stimulation.

Aged↗
PubMed1998

Arsenic enhancement of skin neoplasia by chronic stimulation of growth factors.

Although numerous epidemiological studies have shown that inorganic arsenicals cause skin cancers and hyperkeratoses in humans, there are currently no established mechanisms for their action or animal models. Previous studies in our laboratory using primary human keratinocyte cultures demonstrated that micromolar concentrations of inorganic arsenite increased cell proliferation via the production of keratinocyte-derived growth factors. As recent reports demonstrate that overexpression of keratinocyte-derived growth factors, such as transforming growth factor (TGF)-alpha, promote the formation of skin tumors, we hypothesized that similar events may be responsible for those associated with arsenic skin diseases. Thus, the influence of arsenic in humans with arsenic skin disease and on mouse skin tumor development in transgenic mice was studied. After low-dose application of tetradecanoyl phorbol acetate (TPA), a marked increase in the number of skin papillomas occurred in Tg.AC mice, which carry the v-Ha-ras oncogene, that received arsenic in the drinking water as compared with control drinking water, whereas no papillomas developed in arsenic-treated transgenic mice that did not receive TPA or arsenic/TPA-treated wild-type FVB/N mice. Consistent with earlier in vitro findings, increases in granulocyte/macrophage colony-stimulating factor (GM-CSF) and TGF-alpha mRNA transcripts were found in the epidermis at clinically normal sites within 10 weeks after arsenic treatment. Immunohistochemical staining localized TGF-alpha overexpression to the hair follicles. Injection of neutralizing antibodies to GM-CSF after TPA application reduced the number of papillomas in Tg.AC mice. Analysis of gene expression in samples of skin lesions obtained from humans chronically exposed to arsenic via their drinking water also showed similar alterations in growth factor expression. Although confirmation will be required in nontransgenic mice, these results suggest that arsenic enhances development of skin neoplasias via the chronic stimulation of keratinocyte-derived growth factors and may be a rare example of a chemical carcinogen that acts as a co-promoter.

Animals↗
PubMed1998

In vitro cytotoxicity of IgG antibodies on vascular endothelial cells from patients with endemic peripheral vascular disease in Taiwan.

A unique peripheral vascular disorder called 'blackfoot disease' is endemic in a limited area on the south-west coast of Taiwan. Clinically, the signs and symptoms of blackfoot disease (BFD) are similar to those of arteriosclerosis and Buerger's disease. A destruction of vascular endothelial cells (ECs) takes place at an early stage in the affected limbs. Currently, the cause of BFD is believed to be artesian drinking water containing a high concentration of arsenic and/or humic substances, although the mechanism of EC destruction is not entirely understood. The purpose of the present study was to examine the factors related to EC damage in BFD. Thus, we investigated the effects of purified IgG collected from patients with BFD (BFD-IgG) and from normal controls (N-IgG) on cultured EC. We found that: (1) EC binding activity of BFD-IgG was significantly higher than that of N-IgG; (2) BFD-IgG, at a concentration higher than 100 microg/ml but not N-IgG, induced concentration-dependent EC cytotoxicity; (3) BFD-IgG at a concentration of 100 microg/ml stimulated neither the release of von Willebrand factor nor the expression of intercellular adhesion molecule-1 by EC. Fluorescent video microscopic examination revealed an increase in transcapillary and interstitial diffusion of nailfold capillary loops in clinically normal fingers of BFD patients. These findings strongly suggested that immunological mechanisms played a significant role in the pathogenesis of BFD. We propose that only persons who produce the IgG anti-endothelial cell antibody are potential victims of BFD.

Antibodies, Anti-Idiotypic↗
PubMed1998

Inhibitory effects of berberine on voltage- and calcium-activated potassium currents in human myeloma cells.

The effects of berberine, an isoquinoline alkaloid, were investigated in human myeloma cells. In cells with intracellular Ca2+ concentration ([Ca2+]i) = 10 nM, the depolarizing square pulses from -80 mV elicited an instantaneous outward current with an inactivation. This outward current was voltage dependent, activating at -30 mV and showed inactivation with repetitive depolarization, and was hence believed to be n type voltage-activated K+ current (IK(V)). Berberine (30 microM) produced a prolongation in the recovery of IK(V) inactivation. In cells with [Ca2+]i = 1 microM, berberine also inhibited A23187-induced IK(Ca). Berberine (1-300 microM) caused the inhibition of IK(V) and IK(Ca) in the concentration-dependent manners. The IC50 values of berberine-induced inhibition of IK(V) and IK(Ca) were approximately 15 microM and 50 microM, respectively. In inside-out configurations, berberine inside the pipette suppressed the activity of K(Ca) channels without changing the single channel conductance. Berberine also inhibited the proliferation of this cell line and the IC50 value of berberine-induced inhibition of cell proliferation was 5 microM. Thus, the cytotoxic effect of berberine in cancer cells may be partially explained by its direct blockade of these K+ channels.

Antineoplastic Agents↗
PubMed1998

Influence of referral source on return compliance of adolescents.

PURPOSE: To determine the effect of the source of referral on appointment compliance of adolescents to referring doctors or to consultants at tertiary medical centers. METHODS: This analysis included 421 adolescent patients aged 10-18 years who were referred to the tertiary teaching hospital in Taiwan by 75 primary care doctors, including 56 pediatricians and 19 general practitioners in 1987-1996. Medical records were abstracted to determine clinical severity and demography. Data of compliance with return appointments were collected by an independently trained interviewer. RESULTS: A total of 18.07% of referrals were initiated by patients or families and 81.93% were initiated by primary care doctors. More severe illness was found in patient-initiated referrals than in doctor-initiated referrals. After controlling for demographic, family features, medical payment, and doctor specialty, this study showed that if the referral were initiated by patients or families, adolescent patients were less likely to return to either the primary care doctors or tertiary teaching hospitals. CONCLUSIONS: Although in a competitive environment, follow-up care is more likely to occur for both primary care doctors and consultants at tertiary teaching hospitals when the referral was initiated by primary care doctors.

Adolescent↗