Biomedical subjects

H-C Kuo

Publications and source records attributed to H-C Kuo.

7 recordsLinked to original sources

PubMed2006

Derivation, characterization and differentiation of human embryonic stem cells: comparing serum-containing versus serum-free media and evidence of germ cell differentiation.

BACKGROUND: This study was designed to establish human embryonic stem cell (hESC) lines, to identify the differences when maintained in serum-containing versus serum-free medium and to test their potential of in vitro differentiation. METHODS: Procedures including immunosurgery were performed on 11 donated human blastocysts to establish hESC lines. The cell lines were characterized and maintained using either serum-free or serum-containing media to compare their morphology, Oct-4 expression, apoptosis and growth speed. Differentiation of these lines was evaluated by the morphology and the expression of genes belonging to the three embryonic germ layers and the germ cell lineage. RESULTS: Three hESC lines were established, and they grew at similar speed in both media (serum-containing or serum-free), but hESC cultured in serum-containing medium yielded significantly higher percentages of morphologically good colonies and cells expressing Oct-4. These cell lines differentiated spontaneously in vitro into cells expressing markers belonging to all three embryonic germ layers and germ cell markers, including c-Kit, STELLA, VASA and growth differentiation factor 9 (GDF9), in directly adherent culture. CONCLUSIONS: Three hESC lines with Taiwanese ancestry have been established, and they retain the in vitro differentiation potential with or without embryoid body (EB) formation. The data support that hESC may be capable of differentiation into germ cells although further confirmation is needed. It is also suggested that strategies such as stepwise adaptation will be needed before implementing a serum-free culture condition for hESC lines that have previously been derived in a medium containing serum.

Apoptosis↗

PubMed2006

Lumbar spinal dural arteriovenous fistula presenting with brainstem symptomatology: A case report.

This report is about a rare case of a lumbar spinal dural arteriovenous fistula (DAVF) with distant brainstem symptoms of vertigo and ataxia. Brain magnetic resonance imaging (MRI) demonstrated a high signal abnormality in the lower pons, medulla, and cervico-medullary junction, presumably related to venous hypertension. Spinal MRI revealed markedly dilated veins along the dorsal aspect of the cord, while spinal angiography confirmed the presence of a lumbar spinal DAVF. Because lumbar DAVF may cause remote brainstem symptoms, spinal DAVF should be considered in the differential diagnosis of high signal MRI abnormalities localized in the brainstem. Properly extending the scanning range is essential in the diagnosis.

Aged↗

PubMed2006

Novel mutations at carboxyl terminus of CIC-1 channel in myotonia congenita.

OBJECTIVES: Myotonia congenita (MC), caused by mutations in the muscle chloride channel (CLCN1) gene, can be inherited dominantly or recessively. The mutations at the carboxyl terminus of the CLCN1 gene have been identified in MC patients, but the functional implication of these mutations is unknown. MATERIAL AND METHODS: Direct sequencing of polymerase chain reaction products covering the whole coding region of the CLCN1 gene was performed in a MC family. This study was designed to investigate the clinical manifestations and genetic analysis of the CLCN1 gene. RESULTS: We identified two novel mutations, 2330delG and 1892C>T, from a genetic screening of the CLCN1 gene in the MC family. The 2330delG mutant allele producing a fs793X truncated protein was identified in a heterozygous state in all the patients. The 1892C>T nucleotide change induced a missense mutation (T631I) found in several asymptomatic individuals, indicating that it may not be associated with MC. Intriguingly, the 2330delG mutation was also found in an asymptomatic subject who also carried the 1892C>T mutation. CONCLUSION: The data indicate that the fs793X mutant protein causes dominantly inherited MC. Because the mutation has been found in a recessive pedigree, the fs793X mutation may have a dual inheritance pattern.

Adult↗

PubMed2006

DMT1: which metals does it transport?

DMT1-Divalent Metal (Ion) Transporter 1 or SLC11A2/DCT1/Nramp2 - transports Fe2+ into the duodenum and out of the endosome during the transferrin cycle. DMTI also is important in non-transferrin bound iron uptake. It plays similar roles in Mn2+ trafficking. Voltage clamping showed that six other metals evoked currents, but it is unclear if these metals are substrates for DMT1. This report summarizes progress on which metals DMT1 transports, focusing on results from the authors' labs. We recently cloned 1A/+IRE and 2/-IRE DMT1 isoforms to generate HEK293 cell lines that express them in a tetracycline-inducible fashion, then compared induced expression to uninduced expression and to endogenous DMT1 expression. Induced expression increases approximately 50x over endogenous expression and approximately 10x over uninduced levels. Fe2+, Mn2+, Ni2+ and Cu1+ or Cu2+ are transported. We also explored competition between metal ions using this system because incorporation essentially represents DMT1 transport and find this order for transport affinity: Mn>?Cd>?Fe>Pb-Co-Ni>Zn. The effects of decreased DMT1 also could be examined. The Belgrade rat has diminished DMT1 function and thus provides ways of testing. A series of DNA constructs that generate siRNAs specific for DMT1 or certain DMT1 isoforms yield another way to test DMT1-based transport.

Animals↗

PubMed2005

Berberine induces apoptosis through a mitochondria/caspases pathway in human hepatoma cells.

Berberine, a main component of Coptidis Rhizoma, is a plant alkaloid with a long history of medicinal use in Chinese medicine. Berberine has indicated significant antimicrobial activity against a variety of organisms including bacteria, viruses, fungi. The mechanism by which berberine initiates apoptosis remains poorly understood. In the present study, we demonstrated that berberine exhibited significant cytotoxicity in hepatoma HepG2 cells but is ineffective in Chang liver cells. Herein we investigated cytotoxicity mechanism of berberine in HepG2 cells. The results showed that HepG2 cells underwent internucleosomal DNA fragmentation after 24-h treatment with berberine (50 microM). Moreover, berberine induced the activation of caspase-8 and -3, and caused the cleavage of poly ADP-ribose polymerase (PARP) and the cytochrome c release, whereas the expression of Bid and anti-apoptosis factor Bcl-XL were decreased markedly. The loss of mitochondrial membrane potential (Delta psim) at 24 h and activation of Fas at 12 h were also seen in the berberine-treated HepG2 cells. These findings supported the fact that the inhibitors of caspases, DEVD-FMK, IETD-FMK and VAD-FMK, prevented apoptosis and restored the expression of Bcl-XL, Bcl-2 and Bid. These results indicated that the potential of anti-hepatoma activity of berberine may be mediated through a caspases-mitochondria-dependent pathway.

Apoptosis↗

PubMed2005

Acute painful neuropathy in thallium poisoning.

Dysesthesia, allodynia, distal muscle weakness, and sensory impairment were noted in two patients with acute thallium intoxication. Two months later, nerve conduction studies showed an axonal degeneration. Sural nerve biopsy disclosed a decreased fiber density in the large myelinated fibers. Quantitative sensory testing also revealed an impairment of pinprick, temperature, and touch sensations. Cutaneous nerve biopsy confirmed a loss of epidermal nerves indicating an involvement of the small sensory nerves.

Acute Disease↗

PubMed2003

Effectiveness of intravesical resiniferatoxin in treating detrusor hyper-reflexia and external sphincter dyssynergia in patients with chronic spinal cord lesions.

OBJECTIVE: To investigate the therapeutic effect of resiniferatoxin in patients with chronic spinal cord lesions, as detrusor hyper-reflexia and external sphincter dyssynergia (DESD) are common phenomenon in such patients. PATIENTS AND METHODS: Twenty patients with chronic spinal cord lesions and DESD refractory to anticholinergic treatment were enrolled in a prospective study. They were treated with 30 mL of 10 micro mol/L resiniferatoxin for 30 min. Four types of response were recorded during instillation: type 1, a sustained high-pressure detrusor contraction followed by complete acontractility; type 2, a high-pressure contraction followed by progressively lower contractions; type 3, intermittent high-pressure detrusor contractions throughout the instillation; type 4, intermittent low-pressure detrusor contractions. The changes in clinical symptoms and urodynamics at baseline, during resiniferatoxin instillation and 1 month after treatment were compared. RESULTS: All patients had DESD and 10 had autonomic dysreflexia; 18 had urinary incontinence and 13 had difficult urination. Continence and/or difficult urination improved in 12 patients, including all five with type 1, four with type 2, two with type 3 and only one with a type 4 response. Four patients became dry during the day and eight had less urgency and fewer incontinence episodes, and a significantly increased voided volume. Of the 13 patients who complained of difficult urination, eight had an improvement either by spontaneous voiding (five) or the Crede manoeuvre to voiding (three). The mean (sd) maximum cystometric capacity increased significantly after treatment, from 102.1 (31.5) to 236.6 (88.6) mL (P < 0.001), but the detrusor pressure showed no significant change, at 55.9 (23.2) to 47.5 (28.1) cmH2O. The external urethral sphincter showed intermittent activity during reflexic detrusor contractions at baseline. CONCLUSION: Resiniferatoxin at 10 micro mol/L has a clinical effect on two-thirds of patients with a spinal cord lesion and detrusor hyper-reflexia, but not on the DESD. The initial response to resiniferatoxin instillation might predict a favourable therapeutic outcome.

Administration, Intravesical↗