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C-H Yang

Publications and source records attributed to C-H Yang.

24 records · Page 2Linked to original sources
PubMed2004

Seeing the gene therapy: application of gene gun technique to transfect and decolour pigmented rat skin with human agouti signalling protein cDNA.

We developed a gene gun method for the transfer of human agouti signalling protein (ASP) cDNA to alter rat skin colour in vivo. Human ASP cDNA was cloned into a modified cytomegalovirus plasmid and delivered to the skin of Long-Evans rats by gene gun bombardment. Skin pigmentation, body weight and blood sugar of ASP cDNA-transfected rats were recorded against the control group, which were injected with plasmids encoding for green fluorescent protein. The treated skin showed lighter skin colour after 3 days of ASP gene transfection. This depigmentation effect was most prominent on day 14 and the skin gradually returned to its original pigmentation by day 28. Successful transfection of ASP gene in skin and hair follicles, as well as downregulation of melanocortin-1 receptor (MC1R) and tyrosinase expression upon treatment, was confirmed using immunohistochemistry and Western blot analysis. Body weight and blood sugar in the treated rats did not show statistically significant differences as compared to control groups. These observations demonstrate that gene transfer using the gene gun method can induce high cutaneous ASP production and facilitate a switch from dark to fair colour without systemic pleiotropic effects. Such a colour switch may be that ASP is acting in a paracrine fashion. In addition, this study verifies that ASP exerts its functions by acting as an independent ligand that downregulates the melanocyte MC1R and tyrosinase protein in an in vivo system. Our result offers new, interesting insights about the effect of ASP on pigmentation, providing a novel approach to study the molecular mechanisms underlying skin melanogenesis.

Agouti Signaling Protein↗
PubMed2004

A new approach for determining the stability of recombinant human epidermal growth factor by thermal Fourier transform infrared (FTIR) microspectroscopy.

Based on Fourier transform infrared (FTIR) microspectroscopy, the conformation of rhEGF under the influence of pH, heat treatment, chaotropic salts, concentration of salt and protein structure perturbants was studied. The FTIR spectrum of rhEGF showed that major secondary structures from amide I bands composed of 40.6% beta-sheets, 25.0% reverse turns, 16.5% random coils, 13.0% loops and 4.9% side-chain structures. At extreme pH conditions (pH < 4 and pH > 8), there were changes in intensity of the bands attributed to loop (1658 cm(-1)) and random coil structures, and these bands shifted to lower wavenumbers, indicating changes in protein conformation. Thermal denaturation of rhEGF occurred at 40-76 degrees C and the formation of intermolecular beta-aggregates was revealed by the FTIR spectra. Thermal-irreversible property of rhEGF after second-heating treatment suggested that rhEGF has a poor thermal stability. While investigating the stability of rhEGF in the presence of chaotropic salts, anions induced protein unfolding of rhEGF more significantly than cations. The optimal stabilizing effect was found at the 2 M NaCl added to rhEGF, and expressed the structure of rhEGF more stable on the many components. The bands of loop structure (1654 cm(-1)), beta-sheet (1638 cm(-1)) and intermolecular antiparallel beta-aggregation formation (1694, 1619 and 1612 cm(-1)) seem to be "marked" to be more sensitive in determining environmental changes of rhEGF for FTIR microspectroscopy.

Epidermal Growth Factor↗
PubMed2003

Intractable livedoid vasculopathy successfully treated with hyperbaric oxygen.

We describe a new method for treating livedoid vasculopathy. The typical presentation of livedoid vasculopathy includes chronic, recurrent painful ulcers, satellite scar-like atrophy and telangiectasia involving the lower extremities. Histologically, these lesions show areas of ulceration and dermal vessel occlusion without frank inflammatory cell infiltration. There is currently no satisfactory therapy available for this disease. Hyperbaric oxygen (HBO) has recently established itself as one of the most effective methods of treating ischaemic wounds, including diabetic ulcers. We used this therapy in two patients whose lesions were resistant to multiple therapeutic modalities. Not only did their ulcers respond rapidly to the HBO therapy, but the disturbing wound pain also resolved at the same time. To our knowledge, this is the first successful trial of HBO therapy in livedoid vasculopathy. We believe this to be a very promising new therapy for livedoid vasculopathy and to be worth further investigation.

Adolescent↗
PubMed2002

Gene-gun particle with pro-opiomelanocortin cDNA produces analgesia against formalin-induced pain in rats.

Endogenous opioid peptides play an essential role in the intrinsic modulation and control of inflammatory pain, and could be therapeutically useful. These opioid peptides are synthesized as parts of larger precursor molecules. One such precursor molecule is pro-opiomelanocortin (POMC). In this study, we developed a gene-gun method for the transfer of POMC cDNA in vivo, and investigated its therapeutic effect on inflammatory pain in a rat model of formalin-induced pain. Human POMC cDNA was cloned into a modified pCMV plasmid and delivered to the skin of rats by gene gun. Three days after gene-gun injection, 1% formalin was injected. Endorphin levels were measured in the serum and skin after the formalin test, and skin histology was used to detect endorphin after green fluorescent protein (GFP; control) or POMC cDNA transfer. There was no significant difference in the results of acute nociceptive tests between the experimental and control groups. There was also no difference in response between the groups to phase 1 of the formalin test. However, rats which received POMC cDNA via gene-gun injection showed a significantly reduced response in phase 2 of the formalin test. Endorphin immunoreactivity in the skin increased approximately three- to four-fold in experimental animals compared with GFP-treated controls at day 3 after injection. The phase 2 response in animals treated with formalin and naloxone did not differ significantly from the control, implying that the analgesic effects of POMC cDNA particle injection in phase 2 of the formalin test are reversed by naloxone. There are two major findings from this study. First, in vivo DNA delivery by gene gun to the skin is feasible. Second, the production of beta-endorphin is insufficient to block phasic pain, but is effective against sensitization of the afferent neurons during phase 2 of the formalin test.

Adrenocorticotropic Hormone↗
PubMed2002

Acquired digital arteriovenous malformation: a report of three cases and study with epiluminescence microscopy.

Acquired digital arteriovenous malformation is an abnormal connection between the arteriole and venule in the finger, fed by the digital vessels. Lesions are characterized by small, slightly raised dark-red macules on the distal part of the fingers. In the past, similar cases had been described using the terms 'cutaneous keratotic haemangioma' and 'periungual and subungual arteriovenous tumours'. In this article, we would like to discuss three additional cases that were studied using epiluminescence microscopy. Pathological findings and the possible pathogenesis are also presented.

Adult↗