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Biomedical subjects

H-C Chen

Publications and source records attributed to H-C Chen.

At least 19 recordsLinked to original sources
PubMed2006

Hypokalemic paralysis due to Gitelman syndrome: a family study.

Hypokalemic paralysis is rarely seen as the presenting feature in patients with Gitelman syndrome. We report a Chinese man who presented with periodic paralysis, in whom molecular analysis revealed compound heterozygous inheritance of three mutations of the thiazide-sensitive sodium chloride cotransporter. Family history revealed intrafamilial variation in phenotypes. Gitelman syndrome should be considered as a cause of hypokalemic paralysis, and molecular analysis may help establish the diagnosis.

Adult↗
PubMed2006

Free microvascular transfer of the vermiform appendix for creation of a tracheo-oesophageal fistula: A new method of voice reconstruction.

BACKGROUND: Voice rehabilitation following laryngectomy can take many forms. As its basic premise, vibrating air must be transferred to the mouth where articulation takes place and speech can be produced. It requires a source of air, a conduit for transfer, and a mechanism for prevention of regurgitation and aspiration. Creating a tracheo-oesophageal fistula and maintaining it with a vascularised appendix has been the intention of this report. METHODS: Three patients with an average age of 53 years underwent the procedure of free transfer of the appendix for voice restoration during the months of September 2004 through December 2004. All patients had laryngectomies and one had total cervical oesophageal reconstruction with a pedicled pectoralis major flap. Voice evaluation, swallowing function, and presence of aspiration were evaluated. RESULTS: All flaps survived without complications. The results of swallowing function were unaltered from preoperative levels. All flaps remained patent at an average follow-up period of 8 months. All three patients could produce loud voice, which was intelligible at a reasonable distance. Maximal phonation time was 4s in two patients and 5s in one patient. Voice rehabilitation using the free appendix flap can achieve a phonation time which is low and words and short phrases that are intelligible but limited so far to this level. The donor site morbidity is low and aspiration was not present. The results of this study indicate that this method may have a potential role in voice reconstruction but requires more experience and refinement of this technique.

Anastomosis, Surgical↗
PubMed2006

Baculovirus transduction of human mesenchymal stem cell-derived progenitor cells: variation of transgene expression with cellular differentiation states.

We have previously demonstrated that baculovirus can efficiently transduce human mesenchymal stem cells (MSCs). In this study, we further demonstrated, for the first time, that baculovirus can transduce adipogenic, chondrogenic and osteogenic progenitors originating from MSCs. The transduction efficiency (21-90%), transgene expression level and duration (7-41 days) varied widely with the differentiation lineages and stages of the progenitors, as determined by flow cytometry. The variation stemmed from differential transgene transcription (as revealed by real-time reverse transcription-polymerase chain reaction), rather than from variability in virus entry or cell cycle (as determined by quantitative real-time PCR and flow cytometry). Nonetheless, the baculovirus-transduced cells remained capable of differentiating into adipogenic, osteogenic and chondrogenic pathways. The susceptibility to baculovirus transduction was higher for adipogenic and osteogenic progenitors, but was lower for chondrogenic progenitors. In particular, the duration of transgene expression was prolonged in the transduced adipogenic and osteogenic progenitors (as opposed to the MSCs), implicating the possibility of extending transgene expression via a proper transduction strategy design. Taken together, baculovirus may be an attractive alternative to genetically modify adipogenic and osteogenic progenitors in the ex vivo setting for cell therapy or tissue engineering.

Adipocytes↗
PubMed2006

Lamivudine reverses severe acute hepatitis B and pancytopenia after renal transplantation: a case report.

Pancytopenia is rare after acute hepatitis B infection. The use of lamivudine in the treatment of acute hepatitis B-associated pancytopenia in renal transplant recipients has not been documented. Herein we reported a 21-year-old woman who was infected with acute hepatitis B 6 months after renal transplantation, a condition complicated by pancytopenia. Lamivudine reversed the acute hepatitis in 1 month and the pancytopenia after 3 months, without a change in renal function. Lamivudine was maintained for 2 years without a hepatitis flare-up after 4 years.

Adult↗
PubMed2006

Increased renal calcium and magnesium transporter abundance in streptozotocin-induced diabetes mellitus.

Diabetes is associated with renal calcium and magnesium wasting, but the molecular mechanisms of these defects are unknown. We measured renal calcium and magnesium handling and investigated the effects of diabetes on calcium and magnesium transporters in the thick ascending limb and distal convoluted tubule in streptozotocin (STZ)-induced diabetic rats. Rats were killed 2 weeks after inducing diabetes, gene expression of calcium and magnesium transporters in the kidney was determined by real-time polymerase chain reaction, and the abundance of protein was assessed by immunoblotting. Our results showed that diabetic rats had significant increase in the fractional excretion for calcium and magnesium (both P < 0.01), but not for sodium. Reverse transcriptase-polymerase chain reaction revealed significant increases in messenger RNA abundance of transient potential receptor (TRP) V5 (223 +/- 10%), TRPV6 (177 +/- 9%), calbindin-D28k (231 +/- 8%), and TRPM6 (165 +/- 8%) in diabetic rats. Sodium chloride cotransporter was also increased (207 +/- 10%). No change was found in paracellin-1 (cortex: 108 +/- 8%; medulla: 110 +/- 10%). Immunofluorescent studies of renal sections showed significant increase in calbindin-D28k (238 +/- 10%) and TRPV5 (211 +/- 10%), but no changes in paracellin-1 in Western blotting (cortex: 110 +/- 7%; medulla: 99 +/- 7%). Insulin administration completely corrected the hyperglycemia-associated hypercalciuria and hypermagnesiuria, and reversed the increase of calcium and magnesium transporter abundance. In conclusion, our results demonstrated increased renal calcium and magnesium transporter abundance in STZ-induced diabetic rats, which may represent a compensatory adaptation for the increased load of calcium and magnesium to the distal tubule.

Animals↗
PubMed2006

Esophageal schwannoma with tracheal compression.

An esophageal schwannoma was found in a 73-year-old woman with cough, exertional dyspnea, and progressive dysphagia. Chest imaging showed an upper mediastinal mass (apex, right thoracic cavity) with direct lower tracheal compression. Esophagography and esophagoscopy revealed a tumor in the cervical and upper thoracic esophagus; it was resected from the upper thoracic esophagus followed by cervical esophageal repair. Histology showed oval-to-fusiform cells with palisading and lymphocytic stromal infiltration (immunohistochemistry, S-100 protein-positive). The patient was well one year afterward.

Aged↗
PubMed2005

Esophageal perforation complicating with spinal epidural abscess, iatrogenic or secondary to first thoracic spine fracture?

A 49-year-old drunken man was involved in a motorbike crash. He presented with cervical spine injury and multiple limbs fracture. Neuro-imaging demonstrated disruption of the C5-6 anterior longitudinal ligament, herniation of C3-4 and C5-6 discs, and Th1 compression fracture. The neurological deficits improved after anterior cervical decompression, fusion and fixation. One week later, he suffered from fever and severe upper back pain, and he developed paraplegia subsequently. The following image study disclosed esophageal perforation at the level of Th1 and epidural abscess spreading from levels Th1 to Th5. After proper management and rehabilitation, he achieved good recovery one year later at follow-up. We report the unique case of Th1 fracture with esophageal perforation complicated with spinal epidural abscess. The possible mechanism and the controversy concerning therapy for esophageal perforation are discussed.

Cervical Vertebrae↗
PubMed2005

Increased glomerular and extracellular malondialdehyde levels in patients and rats with focal segmental glomerulosclerosis.

BACKGROUND: Evidence suggests an increase in oxidative stress in patients with chronic kidney disease, as glomerulosclerosis is the prerequisite for chronic kidney disease; whether the oxidative stress already exists early on is not known. MATERIALS AND METHODS: In this study we measured the plasma and urinary levels of malondialdehyde (MDA), the end product of lipid peroxidation, and assessed the immunoreactivity of MDA and superoxide dismutase (SOD) in glomeruli of patients and rats with primary focal segmental glomerulosclerosis (FSGS), and compared our findings with those of minimal change disease (MCD) and normal controls (NC). RESULTS: Our results showed that plasma MDA level was significantly increased in patients with FSGS compared with both patients with MCD and normal controls. The urinary MDA level was also significantly increased and was significantly correlated with plasma MDA level in patients with FSGS. The immunostaining for glomerular MDA and SOD was significantly higher in the patients with FSGS than in either the patients with MCD or NC, and was also significantly higher in rats with puromycin aminonucleoside (PAN)-induced FSGS than in rats with MCD. Glomerular MDA level was significantly correlated with the degree of glomerulosclerosis in the patients with FSGS. CONCLUSIONS: Our data suggest that oxidative stress occurs early on before the onset of renal failure, and may play an important role in the pathogenesis of glomerulosclerosis.

Adult↗
PubMed2005

An uncommonly serious case of an uncommon sport injury.

BACKGROUND: A 55 year old man sustained a severe ocular injury when hit by a cricket ball even though he was wearing a helmet. METHODS: A suprachoroidal haemorrhage was drained and dense intravitreal blood was removed. An inferior buckle was applied with the use of intraocular gas. A macular haemorrhage resolved slowly. RESULTS: Despite several surgical procedures over 1.5 years, the final visual acuity of the patient was only 6/60 because of a dense macular scar. CONCLUSIONS: Helmets worn as protection when playing cricket need to be designed better and be of better material. Eye protection should be worn at all levels of play.

Athletic Injuries↗
PubMed2004

Risks of interleukin-1 genetic polymorphisms and Helicobacter pylori infection in the development of gastric cancer.

BACKGROUND: The host genetic factors that determine the clinical outcomes of Helicobacter pylori-infected individuals remain unclear. AIM: To elucidate the risks of host interleukin-1 (IL-1) genetic polymorphisms and H. pylori infection in the development of gastric cancer. METHODS: In a case-control study of 164 controls and 142 patients with gastric cancer, the IL-1B-511 biallelic polymorphisms and the IL-1RN penta-allelic variable number of tandem repeats were genotyped. RESULTS: The carriage of IL-1RN*2, male gender, old age and H. pylori infection independently increased the risk of gastric cancer, with odds ratios of 3.3 [95% confidence interval (CI), 1.4-7.7], 2.1 (95% CI, 1.2-3.8), 5.3 (95% CI, 3.1-9.0) and 2.2 (95% CI, 1.3-3.8), respectively. H. pylori-infected individuals who were carriers of IL-1RN*2 showed increased risks of both intestinal and diffuse types of gastric cancer, with odds ratios of 11.0 and 8.7, respectively. In addition, these individuals also had a higher score of intestinal metaplasia in the corpus than did uninfected non-carriers. CONCLUSIONS: This study is the first to verify IL-1RN*2 as an independent factor governing the development of gastric cancer in Asian individuals. A combination of H. pylori testing and host genotyping may target the eradication of H. pylori to high-risk individuals.

Adenocarcinoma↗
PubMed2004

Up-regulation of XCR1 expression in rheumatoid joints.

OBJECTIVES: Chemokine receptor-positive cells play a crucial role in controlling synovitis in rheumatoid arthritis (RA). We studied 16 chemokine receptors of the CC, CXC, CX3C and C families by analysing venous blood and synovial fluid samples and synovial tissues from RA patients. METHODS: Mononuclear cells (MNCs) in paired synovial fluid and venous blood samples from 7 RA patients were studied for the expression of CCR1 to 9, CXCR1 to 5, CX3CR1 and XCR1 by quantitative reverse transcription polymerase chain reaction (RT-PCR). Expression of chemokine receptors on synovial tissues from 9 RA patients were examined by in situ hybridization. Levels of chemokines were measured by enzyme-linked immunosorbant assay. RESULTS: Higher expression levels of XCR1 and CCR5 in MNCs from synovial fluid, as compared with those from venous blood, were consistently demonstrated in all RA patients (P<0.01). Through in situ hybridization, XCR1 expression was detected in infiltrating MNCs and synoviocytes in synovial tissues. Levels of lymphotactin, the ligand of XCR1, were significantly higher in the joint fluid than those in the paired serum samples (P<0.01). CONCLUSIONS: We found an up-regulation of XCR1 expression in MNCs from the rheumatoid joint, and detected XCR1 expression in infiltrating MNCs in synovial tissues, as well as increased lymphotactin levels in synovial fluid. XCR1-positive cells may play a role in rheumatoid joints.

Adult↗
PubMed2004

High compliance rates observed for follow up colonoscopy post polypectomy are achievable outside of clinical trials: efficacy of polypectomy is not reduced by low compliance for follow up.

INTRODUCTION: The National Polyp Study demonstrated that removal of adenomas with at least a three-year follow up reduced the incidence of colorectal cancer. However, compliance with follow up colonoscopy may affect the estimates of reduction in colorectal cancer incidence demonstrated by the National Polyp Study. While an 80% compliance rate for follow up colonoscopy was achieved during the National Polyp Study, the compliance rate for follow up colonoscopy is unknown in the general population. The aim of this study was to determine the compliance rate for follow up colonoscopy and factors which affect follow up. METHODS: A retrospective medical record review to identify patients who had adenomatous polyps excised in 1997 was undertaken. Patients who had inflammatory bowel disease, a prior history of colorectal cancer, familial adenomatous polyposis syndrome, colonic surgery; incomplete polypectomy or incomplete colonoscopy, and those patients who died before planned follow up, were excluded from analysis. Follow up was performed by telephone survey. RESULTS: Three hundred and thirty-three patients were identified (196 males; 147 females) with a mean age of 70 years. Three hundred and thirty-one (99%) of 333 had a documented recommendation for follow up of three years or less. Thirty-four percent (113 of 333) had previously undergone colonoscopy; 29% (98 of 333) had previously undergone polypectomy and 54% (180 of 333) were symptomatic at the time of the colonoscopy. Twenty-eight percent (40 of 141) had a family history of colorectal cancer. Pathology at polypectomy included a single polyp and polyps less than 10 mm in 68% and 88% of cases, respectively. Follow up was available in 211 of these cases, 179 (85%) of which had been compliant with follow up colonoscopy. In a univariate analysis, previous colonoscopy (P = 0.035), previous polyps (P = 0.043), asymptomatic status at time of colonoscopy (P = 0.021), polyp size (P = 0.008) and number of polyps (P = 0.010) were significantly associated with patients who were compliant with follow up colonoscopy. A multivariate logistics regression analysis revealed number of polyps (P = 0.036) and polyp size (P = 0.045) to be statistically significantly associated with compliance. CONCLUSION: Compliance with follow up colonoscopy after polypectomy is greater than 80%, regardless of age, education, family history, prior colonoscopy, or prior polypectomy. Risk reduction published in the National Polyp Study may likely reflect what can be achieved through the general use of colonoscopy for surveillance.

Adenomatous Polyps↗
PubMed2004

Removal of sodium from the solvent reduces retinal pigment epithelium toxicity caused by indocyanine green: implications for macular hole surgery.

BACKGROUND: s/aims: Staining of internal limiting membrane with indocyanine green (ICG) has been reported to be associated with postoperative atrophic retinal pigment epithelium (RPE) change. Here the authors examined whether removing sodium from the solvent reduces ICG induced RPE cytotoxicity. METHODS: Human RPE cells were exposed to ICG (0.25 and 0.025 mg/ml) reconstituted with balanced salt solution (BSS) or Na(+) free BSS. Light microscopy, trypan blue dye exclusion, acridine orange/ethidium bromide staining, and DNA electrophoresis were used to evaluate the cytotoxic effects of ICG. ICG uptake was measured by optical absorption at 790 nm. RESULTS: Sodium removal reduced the ICG induced changes in cell morphology and improved the RPE cell viability. When RPE cells were incubated for 4 hours in 0.25 mg/ml ICG dissolved in BSS and sodium free BSS, 86.3% (SD 6.7%) and 2.4% (1.1%) of the cells were stained with trypan blue, respectively. After ICG treatment, RPE dies mainly through a necrotic mechanism. ICG uptake by RPE was also reduced with sodium removal. CONCLUSIONS: ICG induced cytotoxicity in cultured human RPE was reduced with removal of sodium from the solvent. This reconstitution method may provide a safer intravitreal use of ICG in macular hole surgery.

Cells, Cultured↗
PubMed2003

Tyrosine-kinase expression profiles in human gastric cancer cell lines and their modulations with retinoic acids.

Many protein tyrosine kinases are key regulators involved in cellular growth, differentiation, development, apoptosis and signal transduction pathways. Obtaining a comprehensive tyrosine-kinase expression profile in tumour cells is essential to learning more about their oncogenic potentials and responses to various chemotherapeutic reagents - such as retinoic acid, which has been shown to suppress the growth of gastric cancer cells and modulate gene expression. Expression of tyrosine kinases in retionic acid-treated cancer cells was investigated by reverse trancriptase-polymerase chain reaction (RT-PCR) and a novel restriction analysis of gene expression (RAGE) display technique. We first established comprehensive tyrosine-kinase profiles in different human gastric cancer cell lines. In cells treated with 9-cis-retinoic acid or all-trans-retinoic acid, we found that two PTKs (Eph and Hek5) appeared to be upregulated. In the present study, we demonstrate an efficient and simple RAGE approach for examining tyrosine kinases' expression in tumour cells and their alterations following drug treatments.

Gene Expression Profiling↗
PubMed2003

Corticotropin-releasing hormone (CRH) expression and protein kinase A mediated CRH receptor signalling in an immortalized hypothalamic cell line.

Corticotropin-releasing hormone (CRH) is a 41 amino acid neuropeptide which plays an important role in the stress response in the hypothalamus. We describe the development of an immortalized hypothalamic cell line which expresses CRH. We hypothesized that this cell line would possess the relevant characteristics of parvocellular CRH-expressing neurones such as glucocorticoid receptor (GR) expression and vasopressin (VP) coexpression. For production of hypothalamic cells, embryonic day 19 rat pup hypothalami were dissected and dissociated into tissue culture dishes. They were immortalized by retrovirus-mediated transfer of the SV40 large T antigen gene at 3 days of culture and then screened for expression of CRH following dilution cloning. One cell line was chosen (IVB) which exhibited CRH-like immunoreactivity (CRH-LI) and expressed CRH, VP and CRH1 receptor RNA via the reverse transcriptase-polymerase chain reaction. In addition, the cell line expressed the neuronal marker, microtubule-associated protein-2. We verified that the CRH-LI from IVB cell lysates coeluted with CRH standard via reversed-phase high-performance liquid chromatography (HPLC). Furthermore, oxidation of the lysate converted its HPLC profile to that identical with oxidized CRH standard. In addition, IVB cells exhibited high affinity binding to CRH. Incubation of IVB cells with CRH lead to increases in cAMP levels and protein kinase A activity in a concentration-dependent manner. Incubation of IVB cells with CRH also resulted in increases in phospho-cyclic-AMP response element binding protein (CREB) immunostaining as detected by immunocytochemical analysis. Finally, CRH treatment of IVB cell lines has been linked to CREB-mediated gene expression as determined via the PathDetect CREB trans-reporting system. The characteristics of IVB cells, such as CRH and VP coexpression, GR expression and a biologically active CRH-R1-mediated signalling pathway, suggest that this neuronal cell line may serve as model of parvocellular CRH neurones.

Animals↗
PubMed2003

Inflammatory pseudotumour associated with chronic persistent Eikenella corrodens infection: a case report and brief review.

Inflammatory pseudotumour is an uncommon mass forming lesion, representing the histological expression of an infective or reactive/reparative process (pseudotumour) in most cases, and a bona fide neoplasm (for example, inflammatory myofibroblastic tumour) in a minority of cases. This report describes the case of an inflammatory pseudotumour with a pathology that unveiled proliferative CD68 positive and actin negative spindle shaped cells, with a mild mixed inflammatory infiltrate, and a culture that yielded an uncommon fastidious bacillus, Eikenella corrodens. The clinical course was indolent but protracted, with insidious progression to multifocal non-contiguous lesions, involving the lungs, liver, spleen, left kidney, and deep neck tissue, all of which responded to medical treatment with appropriate antibiotics. It is of paramount importance that clinicians search for an infective cause of an inflammatory pseudotumour, to ensure appropriate treatment.

Chronic Disease↗