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Y H Chuang

Publications and source records attributed to Y H Chuang.

At least 19 recordsLinked to original sources
PubMed2004

Alterations in the basement membrane zone in pili annulati hair follicles as demonstrated by electron microscopy and immunohistochemistry.

BACKGROUND: Pili annulati is a rare autosomal dominant inherited hair shaft abnormality in which clinical examination reveals alternating light and dark bands leading to a shiny appearance of the hair. The clinically light bands are the abnormal areas due to cavities within the cortex. The pathogenesis remains unknown. OBJECTIVES: To investigate the expression of the basement membrane zone (BMZ) components in pili annulati hair follicles of the scalp. METHODS: Transmission electron microscopy (TEM) was carried out on scalp sections of six individuals with pili annulati and six controls. Longitudinal sections of scalp tissues from four individuals with pili annulati and six normal controls were studied by immunohistochemistry with a panel of monoclonal antibodies to the following BMZ components: alpha(6)beta(4) integrin, laminin 5, LH39 antigen, laminin 1, collagen IV and collagen VII. RESULTS: Using TEM, pili annulati scalp specimens exhibited a reduplicated lamina densa in the region of the root bulb in comparison with the single thin electron-dense band in controls. Using immunohistochemistry, there was a wavy BMZ in pili annulati follicles with antibodies to components of the lamina lucida, lamina densa and anchoring fibrils, whereas the BMZ in control hair follicles was as a smooth linear band. The expression of the hemidesmosome-associated alpha(6)beta(4) integrin was linear in both pili annulati and control hair follicles. CONCLUSIONS: Our results suggest that the genetic defect may be a mutation in proteins involved in signalling and regulation of formation and degradation of the lamina densa and sublamina densa region resulting in abnormal assembly or remodelling of the BMZ.

Adult↗
PubMed2003

Comparison between the expression of basement membrane zone antigens of human interfollicular epidermis and anagen hair follicle using indirect immunofluorescence.

BACKGROUND: The composition of the basement membrane zone (BMZ) or dermal-epidermal junction in the interfollicular skin has been well documented. However, little is known about the BMZ or connective tissue-epithelial junction along the hair follicle. OBJECTIVES: To determine whether the BMZ antigens in the interfollicular epidermis are also present in the BMZ of the anagen hair follicle and to compare whether the expression and distribution of the BMZ components vary between the interfollicular epidermis and the anagen follicle and within different regions of the hair follicle. METHODS: Longitudinal cryostat sections of scalp margin specimens from four adult patients undergoing cosmetic surgery, and without known pathology were stained with a panel of monoclonal and polyclonal antibodies to different BMZ constituents using standard indirect immunofluorescence. RESULTS: All the BMZ antigens found in the normal interfollicular epidermis were expressed in the anagen follicle; however, there were regional variations in the intensity and patterns of fluorescence. All the antigens were expressed in a continuous linear pattern along the BMZ of the interfollicular skin, the infundibulum, and the middle part of the hair follicle. Differences were observed in the lower follicle and the hair bulb. There was continuous expression throughout the BMZ of the follicle of laminin-1 and collagen IV, but in contrast, expression of other antigens decreased down the lower follicle. There was weak or even negative staining with antibodies to alpha 6 beta 4 integrin, laminin-5, anchoring filaments, and type VII collagen in the outer aspect of the bulb compared with the hair papilla. In addition, there were special patterns observed along the bilateral middle and lower follicle. CONCLUSIONS: Despite the common embryological origin between the interfollicular epidermis and the hair follicle, there is variation in the expression of the BMZ antigens. This may be explained by the histological specialization and functional requirements that reflect the dynamic hair growth cycle.

Adult↗
PubMed2000

Expression of transforming growth factor-beta1 and its receptors related to the ureteric fibrosis in a rat model of obstructive uropathy.

PURPOSE: Transforming growth factor (TGF-beta) is a multifunctional cytokine that may stimulate fibroblast proliferation and regulate the synthesis of matrix components. To elucidate the role of TGF-beta1 in the process of ureteric fibrosis in obstructive uropathy, we conducted this study. MATERIALS AND METHODS: The expression of TGF-beta1 and TGF-beta receptors I, II, III were studied in 54 rats by the method of immunohistochemistry. RESULTS: The degree of smooth muscle hypertrophy and serosa thickening aggravated gradually along the course of ureteric ligation. The expression of TGF-beta1 in the serosa layer was noticed from day 7 after ligation. The expression of TGF-beta1 and receptors in the serosa layer progressively increased during the period of ureteric obstruction, reached a peak on day 21 after ligation, and then declined. The expression of TGF-beta1 and TGF-beta receptors (II and III) in the serosa layer was correlated significantly (r = 0.8048 and 0.7974, respectively; p values both <0.0001). The expression of TGF-beta1 also correlated significantly with the thickening of serosa layer and the severity of hydroureter (r = 0.6921 and 0.5394, respectively; p values both <0.005). The expression of TGF-beta1 and TGF-beta receptors in the smooth muscle layer was transient and weak, and the expression of TGF-beta1 and TGF-beta receptors was accompanied with the fibrosis in the muscle layer. CONCLUSIONS: We conclude that TGF-beta1 might participate in the progression ofureteric fibrosis in obstructed ureters.

Animals↗
PubMed2000

Spinal anesthesia in MELAS syndrome: a case with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes.

MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes) is one of the classic mitochondrial encephalomyopathies with variable clinical presentation and multisystem involvement. Enhanced sensitivity to neuromuscular blockade or anesthetic agents and susceptibility to malignant hyperthermia in these patients have ever been reported, all of which complicate the management of general anesthesia. To avoid these appalling troubles in general anesthesia, we chose spinal anesthesia for a patient with MELAS syndrome receiving appendectomy. The patient obtained adequate anesthesia and good recovery without neurologic sequelae. Although there is little information about the application of regional anesthesia in MELAS patients, we demonstrate that it may be a satisfactory choice. However, it is suggested that regional anesthesia is performed only when neurological abnormalities of spinal cord or peripheral nerves are definitely ruled out.

Adult↗
PubMed1998

Tissue damage and regeneration of ureteric smooth muscle in rats with obstructive uropathy.

OBJECTIVE: To investigate regeneration in obstructed ureters and to elucidate the role of hyperplasia in the thickening of the smooth muscle layer in the late stages of complete ureteric obstruction. MATERIALS AND METHODS: The expression of Ki-67 antigen, c-Fos, c-Jun and c-Myc in the smooth muscle layer of obstructed ureters was determined using immunohistochemistry in 40 Sprague-Dawley rats. After unilateral ligation of the ureter, five rats each were killed for examination at 1, 3, 7, 10, 14, 21, 28 and 42 days after ligation: dive rats that underwent a sham operation were also examined as controls. RESULTS: The severity of hydroureter and thickening of the smooth muscle layer progressed consistently in the ligated ureters, but no mitosis was detected in myocytes within 14 days of ligation. Fibrosis in the smooth muscle layer appeared 21 days after ligation and progressed. There was no expression of Ki-67 antigen and oncoproteins until 14 days after ligation. The expression of Ki-67 and c-Myc increased gradually to a peak after 28 days, then declined. However, the expression of c-Fos and c-Jun was low and transient. CONCLUSION: Cell regeneration is impaired in the damaged muscle layer of obstructed ureters. Only hypertrophy and not hyperplasia of the smooth muscle layer developed during the course of complete ureteric obstruction in this rat model of obstructive uropathy.

Animals↗
PubMed1997

Simultaneous occurrence of papulonecrotic tuberculide and erythema induratum and the identification of Mycobacterium tuberculosis DNA by polymerase chain reaction.

The simultaneous occurrence of two tuberculides in one patient is rare. We report the case of a 32-year-old man presenting with both papulonecrotic tuberculide and erythema induratum. Mycobacterial DNA was identified from both skin lesions by polymerase chain reaction using formalin-fixed and paraffin-embedded tissues, suggesting that tuberculides are related to tuberculosis. New skin lesions developed after the patient discontinued his medication on his own initiative, 2 months after triple antituberculous therapy had been started. It is important to continue therapy for a prolonged period.

Adult↗
PubMed1997

Influence of furosemide on the ureteric damage in a rat model of obstructive uropathy.

Furosemide has been used in the diuretic renography and diuretic radionuclide scan to evaluate the severity of hydroureter and hydronephrosis. To elucidate the influence of furosemide on obstructed ureters, unilateral ligation of ureter was performed in 45 rats. Twenty-four of the rats received intramuscular injections of furosemide (6 mg/kg/day) after the third day postligation. Eight rats were sacrificed for examination on days 7, 10 and 14 after ligation, respectively. The remaining 21 untreated rats were also sacrificed for comparison. The severity of hydroureter and hydronephrosis in the ligated side of the furosemide-treated rats was significantly higher than that of the untreated rats. However, the histological changes in the treated and untreated rats showed no significant difference. The ultrastructural alterations aggravated along the course of ureteric obstruction. Intriguingly, the ultrastructural changes were significantly milder in the treated rats. We conclude that the administration of furosemide might increase the severity of hydroureter, but it does not accelerate the ureteric damage of the obstructed ureters.

Animals↗
PubMed1997

Immune effector cells induced by complete Freund's adjuvant exert an inhibitory effect on antigen-specific type 2 T helper responses.

BACKGROUND: It has been well documented that environmental factors such as antigenpresenting cells and related cytokines could affect the development of T helper cells. OBJECTIVE: The purpose of this study is to investigate the effect of different adjuvants on T cell development. METHODS: Ovalbumin (OVA) combined with aluminum hydroxide (Alum) plus pertussis toxin (PT) or complete Freund's adjuvant (CFA) were used to sensitize mice; the production of IgG and IgE anti-OVA antibodies was then followed. In addition, OVA-specific proliferative responses and cytokine production by spleen cells were also investigated. RESULTS: The data showed that the adjuvants themselves could modify the pattern of immune response: (1) IgG2a anti-OVA antibody was higher in mice sensitized with OVA + CFA compared to that of mice sensitized with OVA + Alum + PT; (2) the ratio of IFN-gamma/IL-4 produced by OVA-stimulated spleen cells was higher in mice sensitized with OVA + CFA than that of mice sensitized with OVA + Alum + PT: (3) increased percentage of gamma delta T cells was noted in the peritoneal exudate cells of OVA + CFA immunized mice; and (4) the immune response of mice sensitized with OVA + Alum + PT was inhibited by the adoptively transferred ascitic cells from OVA + CFA immunized mice. CONCLUSION: In general, the data suggested higher IgG2a and the ratio of IFN-gamma/IL-4 was noted in mice sensitized with OVA + CFA. Further elucidation of the regulatory mechanism of allergen-specific T helper cells development and exploration of possible agents for immunotherapy might shed light on the management of atopic diseases.

Aluminum Hydroxide↗
PubMed1997

Early genetic and cellular responses in the smooth muscle layer of obstructed ureters in a rat model of obstructive uropathy.

OBJECTIVE: To investigate the early genetic and cellular responses in the smooth muscle layer of completely obstructed ureters, and to determine whether myocytes proliferate (hyperplasia) in the ureters during the early stage of obstructive uropathy. MATERIALS AND METHODS: The study comprised 35 female Sprague-Dawley rats which had undergone unilateral ligation of their ureters. After ureteric ligation, five rats each were killed and examined at 0.5, 1, 2, 4, 8, 16 and 24 h after ligation. The proximal portion of the ureters was prepared for light and electron microscopy. The expression of c-Fos, c-Jun, c-Myc and Ki-67 antigen was assessed immunohistochemically. RESULTS: c-Fos and c-Jun were detected 2 h after ligation and the expression of these two proteins reached a maximum after 4 h, becoming undetectable 16 h after ligation. The expressions of c-Fos and c-Jun were strongly correlated (r = 0.9854, P < 0.001). The expressions were of c-Myc and Ki-67 antigen was not detected within 24 h after ureteric ligation. The amount of rough endoplasmic reticulum (rER) in the ligated ureters increased soon after complete ligation and the increase continued throughout the period of ureteric obstruction (r = 0.9699, P < 0.001). The change in rER was also significantly correlated with the expression of c-Fos and c-Jun within 8 h after ligation. CONCLUSION: The expression of c-Fos and c-Jun, but not c-Myc, might contribute to the hypertrophy of the ureteric smooth muscle layer during the course of complete ureteric obstruction. There is no hyperplasia in ureteric smooth muscle in the early stages of obstructive uropathy.

Animals↗
PubMed1996

In vitro and in vivo functional analysis of CD5+ and CD5- B cells of autoimmune NZB x NZW F1 mice.

Polyclonal B cell activation has been thought to play the critical role in production of autoantibodies, and possible activation of autoreactive T cells in murine lupus, especially abnormal expansion of CD5+ B cells, is one of the characteristic findings in these mice. The aim of this study was to investigate further the characteristics and function of CD5+ and CD5- B cells. Both CD5+ and CD5- B cells were isolated for in vitro autoantibody production, cytokine expression and in vivo anti-DNA antibody production with reconstitution of severe combined immunodeficient (SCID) mice. The data showed: (i) both CD5+ and CD5- B cells produced a high level of anti-DNA antibody after stimulation with lipopolysaccharide (LPS) plus IL-5; (ii) both peritoneal CD5+ and CD5- B cells expressed a high level of IL-10 mRNA after stimulation with LPS, while in contrast CD5- B cells of non-autoimmune BALB/c mice did not express IL-10 mRNA after stimulation; (iii) SCID mice reconstituted with either CD5+ or CD5- B cells all produced significant levels of anti-DNA antibodies in vivo and manifested with proteinuria. These data suggest both CD5+ and CD5- B cells play important roles in polyclonal B cell activation and subsequent autoantibody production. Generalized polyclonal B cell activation, instead of expanding a certain subpopulation of B cells, contributed to the pathogenesis of autoimmunity in murine lupus.

Animals↗
PubMed1996

Different kinds of antigen-presenting cells exert different effects on T-helper cells development.

It has been well documented that environmental factors such as antigen-presenting cells and related cytokines can affect the development of T-helper cells. The purpose of this study was to investigate the role of different antigen-presenting cells on T-cell development. Ovalbumin (OVA) combined with complete Freud's adjuvant (CFA) was used to sensitize mice subcutaneously or intraperitoneally, and then to follow-up production of IgG and IgE anti-OVA antibodies. In addition, semiquantitative PCR was used to determine the level of cytokine mRNA of different antigen-presenting cells. Resulting data showed that antigen-presenting cells expressed with different characteristics: (1) IgG2a anti-OVA antibody was higher in mice sensitized subcutaneously compared to those sensitized intraperitoneally. (2) The levels of cytokine mRNA were higher in antigen-stimulated spleen cells of mice immunized subcutaneously compared to those of mice immunized intraperitoneally. (3) Langerhans cells expressed a high level of IL-12; in contrast, peritoneal B cells expressed a high level of IL-10, but not IL-12. In summary, cytokine levels such as IL-10 and IL-12 were different among different kinds of APC, and their role in production of different isotypes of antibodies needs further elucidation.

Animals↗
PubMed1996

Growth characteristics of normal and dystrophic myoblasts in primary myoblast cultures.

This study employed immunocytochemistry and toluidine blue counterstaining to compare different procedures utilized in primary myoblast cultures, from which an optimal culture model for normal myoblasts could be derived. The growth characteristics of normal and dystrophic myoblasts were also investigated by means of this model. Results indicate that the requirements for an ideal myoblast culture should include a combined enzyme of 0.25% trypsin and 0.2% collagenase (type IV) (1:1), a preplating time of approximately 15-20 minutes, and a seeding density of 1 x 10(5) cells/ml. Furthermore, the mouse samples should be newborn mice. A better proliferative capacity of myoblasts was noted in an incubator with 10% CO2 coupled with Dulbecco's MEM plus 15% fetal calf serum. With regard to the growth characteristics of normal and dystrophic myoblasts, the doubling time of normal myoblasts was shorter than that of dystrophic myoblasts. In terms of the fusion percentage of myoblasts, dystrophic myoblasts tended to fuse earlier than normal ones, especially after 5 days in culture. The findings of this study are valuable in understanding the myogenesis of myoblasts under different culture conditions. The establishment of requirements for good growth of myoblast cultures will facilitate myoblast transfer therapy. Finally, the growth characteristics of normal and dystrophic myoblasts as well as variances in the proliferation and differentiation of these two types of cells are clarified.

Aging↗
PubMed1995

MELAS syndrome associated with diabetes mellitus and hyperthyroidism: a case report from Taiwan.

MELAS syndrome is a form of mitochondrial myopathy with manifestations of seizure, stroke-like syndrome, lactic acidosis, ragged red muscle fibres and mitochondrial encephalopathy. The syndrome has been reported in association with a variety of endocrine and metabolic disorders including diabetes mellitus (DM), hypothalamo-pituitary hypofunction, hypothalamic growth hormone deficiency and delayed puberty. Mitochondrial DNA (mtDNA) point mutation may be the major pathological defect. However, association of MELAS syndrome with hyperthyroidism has not previously been reported. A case is reported from Taiwan of a 32-year-old woman suffering from MELAS syndrome with associated DM and hyperthyroidism. When the latter was diagnosed in April 1988, the patient underwent subtotal thyroidectomy. There was no family history of thyroid disease. Because of repeated seizures, she had computed tomography (CT) and magnetic resonance imaging (MRI) of the brain which showed focal, low-density lesions over the cerebral hemispheres. Both serum and cerebral spinal fluid lactic acid levels were elevated. Mild elevations of serum T4 and T3 and a high titre of TSH receptor antibody were still present. Hyperglycaemia was noted during hospitalization and DM confirmed by oral glucose tolerance test. Muscle biopsy showed ragged red fibres. DNA analysis showed an A-to-G transition at the 3243rd nucleotide position of the tRNA(Leu(UUR)) gene of the mtDNA from the patient. Quantitative polymerase chain reaction (PCR) and restriction analysis revealed that about 60% of the blood mtDNA was of mutant type. The patient received antithyroid drugs for hyperthyroidism, diet control for DM and anti-epileptic drugs for seizure.

Adult↗
PubMed1995

The temporal relationship between the severity of hydroureter and the dynamic changes of obstructed ureters in a rat model.

OBJECTIVE: To investigate dynamic changes in the obstructed rat ureter and to evaluate the usefulness of the rat model in the study of obstructive uropathy. MATERIALS AND METHODS: Unilateral ligation of the ureter was performed in 26 rats. After ureteric ligation, four to seven rats were killed and examined after 1, 3, 7, 10, and 14 days. The severity of hydroureter and hydronephrosis was assessed by pyelography and the hydroureter-hydronephrosis index. The middle portion of the ureter was prepared for light and electron microscopic observation. Five rats which received a sham operation were also examined as controls. RESULTS: The severity of hydroureter and hydronephrosis in the ligated ureters progressively increased during the period of obstruction (P < 0.005) and reached a maximum 10-14 days after ligation. Hypertrophy of the smooth muscle layer developed on the third day after ligation and proliferation of submucosal connective tissue occurred on the 10th day after ligation. The changes in smooth muscle and connective tissue layers also progressed consistently during ureteric obstruction (P < 0.001 and < 0.005, respectively). The number and size of granular endoplasmic reticulum and Golgi apparatus in the smooth muscle cells increased after ureteric ligation and then caveolae exocytosis developed. Deposition of collagen fibres between muscle cells became apparent later. CONCLUSION: The rat model of hydrouropathy demonstrated a clear temporal relationship between the severity of hydroureter and the dynamic changes in the obstructed ureter and could be used as a conventional method for the study of obstructive ureter.

Animals↗
PubMed1995

CPEO and carnitine deficiency overlapping in MELAS syndrome.

Mitochondrial myopathy, encephalopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome is one of the mitochondrial encephalomyopathies that has distinct clinical features including stroke-like episodes with migraine-like headache, nausea, vomiting, encephalopathy and lactic acidosis. We report a 27-year-old woman who presented with partial seizure, stroke-like episodes including hemiparesis, hemianopia and hemihypethesia, sensorineural hearing loss, migraine-like headache, and lactic acidosis. Brain computed tomographic scan showed encephalomalacia in the right parieto-occipital area and recent hypodensity in the left temporoparieto-occipital area with cortical atrophy. Muscle biopsy revealed ragged-red fibers and paracrystaline inclusions in the mitochondria. Genetic study revealed an A to G point mutation at nucleotide position (np) 3243 of mitochondrial DNA. External ophthalmoplegia and ptosis were also found during two exaggerated episodes in this patient. Therefore, the overlapping syndrome of chronic progressive external ophthalmoplegia in the MELAS syndrome is considered in this case. Furthermore, we also found carnitine deficiency in this patient and she was responsive well to steroid therapy. Muscle biopsy also revealed excessive lipid droplets deposits. Therefore, the carnitine deficiency may occur in MELAS syndrome with the A to G point mutation at np 3243. We recommend the steroid or carnitine supplement therapy be applied to the MELAS syndrome with carnitine deficiency.

Adult↗
PubMed1995

[Study of myoblast culture and myoblast transfer therapy in dystrophic mice].

In this report, we study the suitable conditions for myoblast cultures through analysis of myoblast growth and differentiation, and then try to develop a mouse model for myoblast transfer therapy (MTT). Recently, some research has indicated that Muscular Dystrophy Murine Mice (MDX) have an X-linked recessive dystrophin deficiency which is caused by dystrophin gene point mutation at the X chromosome. Therefore, MDX mice are usually used for MTT models of muscular dystrophy disease. Control mice, C57BL10/SCSN (B-10) were chosen as a source of normal myoblasts. Myoblasts isolated from the hindlimb muscle tissues of two- to three-day-old neonatal B-10 mice were cultured in vitro for one to seven days. Through our modifyied techniques of isolation and culturing conditions, a myoblast purity of 70% could be achieved, with fibroblast the only contaminating cell type. The proliferative capacity and the doubling time of myoblasts were counted from analysis of growth kinetics. While differentiative capacity was analyzed morphologically, we found the fusion of myoblasts was time-dependent. Immunostaining myoblasts of different stages with anti-dystrophin antibody showed that purified myoblasts with the capacity of fusion can express dystrophin and can be utilized as a donating source in MTT. In the MTT experiment, eight young MDX mice were injected with normal myoblasts at a concentration of 1 x 10(6) cells. All transplated mice received daily cyclosporine A injection for immunosuppression. Two to three months later, dystrophin was found in the myoblast-transferred muscles while staining immunocytochemically. The result suggests that we successfully transferred the normal dystrophin gene from the normal myoblasts into the MDX mice since their myoblast-injected muscle could express dystrophin.

Animals↗
PubMed1995

[Clinical significance of dystrophin positive fibers in Duchenne muscular dystrophy].

Dystrophin is a protein product of the Xp 21 gene which is defective in patients with Duchenne muscular dystrophy (DMD). In immunohistochemical staining of dystrophin, the majority of DMD muscle fibers show negative staining. Nevertheless, biopsy specimens from DMD patients labeled with many different antibodies may show a small number of fibers which are clearly dystrophin positive. This very small percentage of dystrophin-positive fibers (DPF) probably represents somatic reversion, suppression of the DMD gene mutation or alternating splicing of dystrophin mRNA. To determine the significance of isolated DPF in muscle specimens of DMD patients, we examined 30 DMD muscle specimens, aged 4 years to 16 years, by the use of monoclonal antibody against the C-terminal region of dystrophin. Additionally, muscle specimens from 2 normal human controls and 2 mice with X-linked muscular dystrophy were used for positive and negative controls, respectively. Muscle specimens from DMD patients and mdx mice showed almost totally negative dystrophin staining in most of their muscle fibers, but in 20 patients, three was a trace of isolated DPF ranging from 0.06% to 0.77%. DMD patients with no isolated DPF seemed to have higher functional disability. In the whole group of 30 patients, a significant negative correlation was found between the abundance of DPF and clinical functional grading (r = -0.85, p < 0.0001, based on linear regression). It is suggested that even the very low concentrations of dystrophin found in DMD patients may have a favorable functional significance.

Adolescent↗