Biomedical subjects

C C Liang

Publications and source records attributed to C C Liang.

At least 19 recordsLinked to original sources

PubMed2006

Effects of internal medicine residency training in AIDS care in Taiwan.

Having contact and interacting with HIV/AIDS patients has long been recognized as a means for improving AIDS-related knowledge and attitudes among physicians and hence for increasing their intention to provide AIDS care. To investigate the impact of one-month residency training in an AIDS inpatient unit on internal medicine residents, this quasi-experimental, pre-post, two-group study, conducted from April 2000 to April 2001, used questionnaires. At follow-up, residents who received training in the AIDS unit (experimental group) were significantly more knowledgeable about HIV/AIDS, had more positive attitudes and greater intention to care for HIV-infected patients than residents who did not receive this training (control group). Results suggest that a one-month AIDS residency training intervention can effectively enhance residents' HIV-related knowledge, attitudes and intention to care for patients infected with HIV.

Adult↗

PubMed2005

Distally based sural island flap for the reconstruction of a large soft tissue defect in an open tibial fracture with occluded anterior and posterior tibial arteries-a case report.

To repair a 10 x 16 cm soft tissue defect of right lower leg that accompanied with occluded anterior and posterior tibial arteries in a 30-year-old man who sustained comminuted type III(B) Gustilo open tibial and fibular fracture, we present a successful reconstruction by using a large distally based sural island flap perfused by the lowermost perforator of the peroneal artery. This flap is a useful alternative for distal extremity reconstruction when anterior and posterior tibial arteries are occluded, as large flaps can be elevated safely based on only one peroneal perforator.

Adult↗

PubMed2002

Molecular cloning and sequence analysis of full-length cDNAs encoding new group of Cyn d 1 isoallergens.

BACKGROUND: Cyn d 1, the major allergen of Bermuda grass pollen, contains some acidic/basic isoforms. The N-terminal amino acid sequences of some acidic Cyn d 1 isoforms were found to be different from those of Cyn d 1 cDNA clones identified previously. METHODS: A predicted 17-meric oligonucleotide probe was designed to fish the unidentified isoallergen cDNAs out of BGP cDNA library. The reactive clones were isolated and verified by sequencing. Two of them were expressed in the yeast Pichia pastoris to obtain recombinant Cyn d 1 proteins. RESULTS: All four cDNA clones encode the full-length Cyn d 1 with mature proteins of 244 amino acid residues. A 97-99% identity was found among the deduced amino acids of these four clones while an 86% identity was elicited between the four clones and the ones previously identified. The predicted isoelectric focusing (pI) values of the newly identified Cyn d 1s are acidic while pIs of the previously identified Cyn d 1s are basic. The two recombinant acidic Cyn d 1 proteins possess the epitopes recognized by mouse and rabbit polyclonal anti-Cyn d 1 antibodies, and have human IgE-binding capacity as revealed by immunodot assay. CONCLUSIONS: The present study identified full-length cDNAs encoding new isoallergens of Cyn d 1, and separated Cyn d 1 gene into an acidic group and a basic group.

Allergens↗

PubMed2001

The expression of human alpha -like globin genes in transgenic mice mediated by bacterial artificial chromosome.

After screening a bacterial artificial chromosome of human genomic DNA library with human HS-40, zeta-, alpha-, and theta-globin probes, a 110-kb clone bearing the whole human alpha-globin gene cluster was obtained and rare restriction endonuclease mapping was performed. The bacterial artificial chromosome DNA was isolated, and transgenic mice were generated. Three founders were detected from 35 newborn mice. The copy numbers were 1, 2, and 2, and the expression of human alpha-globin genes in various tissues at different developmental stages in the transgenic mice was assayed. The human alpha-globin mRNA can be detected in bone marrow, kidney, liver, brain, but not in muscle, testis, or thymus. The human zeta-globin genes were switched off, and the alpha-globin genes were switched at day 11.5 in mouse embryo, indicating that developmental stage-specific expression of the alpha-like globin genes was properly regulated. The human alpha-globin mRNA ranged between 17-68% of the endogenous mouse alpha-globin, suggesting that the expression of human alpha-globin genes is integration site-dependent in transgenic mice. The ratio of human alpha(2)- and alpha(1)-globin gene expression in adult transgenic mouse is about 2.5:1 similar to the expression in human.

Animals↗

PubMed2001

Insulator: from chromatin domain boundary to gene regulation.

An insulator or boundary element is a novel class of regulatory sequence and has properties consistent with a role in limiting enhancer activity; it helps to define the boundary between differentially regulated loci. Originally, an insulator was defined operationally by its ability to protect against positional effects and/or to block distal enhancer activity in transgenic assays, whereas recent experiments have focused on the role of insulators or boundaries in their native context. Many new features have been added to our concept of insulators, thereby revealing the complexity of their function. All these need to be accounted for by successful models. The research of insulator elements should provide new insights into the nature of enhancer function and gene regulation and provide an effective tool in applied gene therapy.

Animals↗

PubMed2001

Sustained activation of extracellular signal-regulated kinase stimulated by hepatocyte growth factor leads to integrin alpha 2 expression that is involved in cell scattering.

We have previously shown that hepatocyte growth factor (HGF) selectively increases the expression of integrin alpha(2) in Madin-Darby canine kidney (MDCK) cells. In this study, we have further investigated the signal transduction pathways responsible for the event and its role in HGF-induced cell scattering. We found that the level of integrin alpha(2)beta(1) expression induced by HGF correlated with the extent of cell scattering and that a functional blocking antibody against integrin alpha(2) at the concentration of 25 microg/ml partially (40%) inhibited the HGF-induced cell scattering. However, in the presence of the specific phosphatidylinositol 3-kinase inhibitor LY294002 or the selective Src family kinase inhibitor PP1, although cells retained their response to HGF for increasing integrin alpha(2) expression, they failed to scatter, indicating that increased expression of integrin alpha(2) alone is not sufficient for cell scattering. Moreover, epidermal growth factor, which induced a transient (1 h) activation of extracellular signal-regulated kinase (ERK) in MDCK cells, only slightly increased integrin alpha(2) expression and failed to trigger cell scattering. Conversely, HGF induced a sustained (at least 12 h) activation of ERK in the cells. Expression of constitutively active ERK kinase (MEK) in MDCK cells led to increased expression of integrin alpha(2) even in the absence of HGF stimulation. In contrast, expression of ERK phosphatase or dominant negative MEK inhibited HGF-induced integrin alpha(2) expression. Taken together, our results suggest that the increased expression of integrin alpha(2)beta(1) by HGF is at least partially required for cell scattering and that the duration of MEK/ERK activation is likely to be a crucial determinant for cells to activate integrin alpha(2) expression and cell scattering.

Animals↗

PubMed2001

Regulation of the transcription factor GATA-1 at the gene and protein level.

GATA-1, an important hematopoietic transcription factor, plays a critical role in differentiation and maturation of erythroid and megakaryocytic cell lines. GATA-1 appears to serve as a factor for virtually all characterized erythroid and megakaryocytic-expressed genes. Thus, defining the mechanisms by which the GATA-1 gene and protein are regulated should provide important clues regarding the establishment of erythroid and megakaryocytic programs of gene expression in committed cells and their maintenance thereafter in maturing precursors. This review focuses on the regulation of GATA-1 expression and elucidates the regulation of GATA-1 at the gene and protein levels. Such research is expected to provide insights into the mechanisms involved in hematopoietic commitment.

Animals↗

PubMed2001

A fast and efficient method for isolation of the BAC end.

As a new developmental vector system, the bacterial artificial chromosome (BAC) has been used widely in constructing genomic libraries and in generating transgenic animals. Isolation of the BAC insert end is useful to analyze the BAC clone. Here, we describe a fast and efficient method to obtain the BAC end by ligating the BAC fragments digested with Not I and another selected restriction enzyme into universal cloning vector, followed by determining the correct clones with HindIII digestion. Further DNA sequencing analysis verified the results mentioned above.

Chromosomes, Artificial, Bacterial↗

PubMed2001

Beyond the locus control region: new light on beta-globin locus regulation.

The locus control region (LCR) is a novel class of cis-acting regulatory sequences that enable high-level, tissue-specific, copy number-dependent, and chromosomal position-independent gene expression in transgenic mice. Recent studies on endogenous beta-globin locus and other loci have offered new insights either in support of or in contrast to our knowledge of the relationship between chromatin conformation and transcriptional regulation, the long-distance interaction between enhancers and promoters, and the developmental switching of multiple-gene loci. Our perceptions of the regulatory roles for LCR and elements beyond the LCR in beta-globin locus regulation have been challenged and demand re-evaluation. A sound elucidation of gene regulation mechanisms may rely on a fine understanding of functional interplay between cis-acting elements and trans-acting factors that participate in gene silencing and activation in their native genomic, cellular, and developmental state.

Animals↗

PubMed2001

The regulatory network controlling beta-globin gene switching.

The human globin gene cluster, which represents a prototypical eukaryotic multigene locus, has been investigated for more than two decades and is classic model for coordinate control of tissue-specific gene expression. It is well known that globin gene expression is restricted to specific tissues and that globin genes are sequentially switched on during development. What intricate regulatory mechanisms account for tissue-specific transcriptional control of globin gene expression? Previous studies have focused on the interactions of trans-acting factors and cis-acting elements including the locus control region (LCR), which is considered a potent enhancer in globin gene switching. More recent studies have not only focused on the local DNA regulatory elements but also on remodelling of chromatin and transcription at the globin gene cluster within the native genomic context. Moreover, several studies have presented extensive data that address whether the LCR is required to open the chromatin. Although there is increased insight into the regulation of the beta-globin gene switching, many aspects relating to the developmental activation of distinct globin genes remain elusive.

Animals↗

PubMed2001

Ultrasonographic and urodynamic evaluation after tension free vagina tape procedure (TVT).

BACKGROUND: This study was carried out to evaluate the urodynamic and ultrasonographic findings after tension-free vagina tape (TVT) procedure on stress urinary incontinent women. METHODS: Ninety women suffering from genuine stress incontinence without pelvic relaxation syndrome underwent surgery. Urodynamic measurement, one-hour pad test and introital ultrasonographic evaluation were performed preoperatively and one year after surgery. Additional ultrasonographic surveillance of the urethra was performed immediately after the operation. The position and mobility of the bladder neck was compared pre- and post-operatively in relation to the inferior edge of the pubic symphysis. RESULT: Eight women were excluded for various reasons. Among the 82 women who completed the study, 76 (93%) were cured, four were improved and two failed. No major intra- or post-operative complications occurred. The position and mobility of the bladder neck showed no significant difference before and after surgery. A urethral knee angle was noted ultrasonographically on cured and improved patients during maximum straining. Nine patients with immediate postoperative voiding difficulty were found to have a pronounced mid-urethra angulation. The symptom and sign were resolved by time after urethra depressing. Urodynamic assessment of the urethral pressure profile and other parameter showed no significant difference before and after the surgery except that a positive pressure transmission in the middle portion of the urethra was noted among 70 (87.5%) of cured and improved subjects. CONCLUSION: Tension-free vagina tape operation is an effective surgical procedure for the treatment of female urinary stress incontinence. The procedure seems neither to change hypermobility nor to elevate the position of bladder neck. Urinary continence after surgery is most probably achieved by creating a dynamic mid-urethral knee angulation by which the urethra is closed i.e. kinked at stress. Lifting of the mid-urethra resulted in postoperative voiding difficulty. It is the important that the tape is placed tension free under the urethra. Introital ultrasonographic surveillance is a suitable technique to visualize the result of the operation.

Adult↗

PubMed2001

End-labeling of long DNA fragments with biotin and detection of DNA immobilized on magnetic beads.

To immobilize DNA fragments onto magnetic beads coated with streptavidin for isolation purpose, it is important to label one biotin molecule at one terminus of DNA fragment. After failure to label long DNA with biotin by PCR and filling-in reaction, a 9.2 kb DNA was labeled with biotin by a modified ligation strategy. A simple method is also reported to detect the quantity and integrity of DNA immobilized on the magnetic beads.

Base Sequence↗

PubMed2001

Hot topics in adeno-associated virus as a gene transfer vector.

Adeno-associated virus (AAV) is a promising viral vector in treating many kinds of hereditary diseases. The broad host range, low level of immune response, and longevity of gene expression observed with this vector have enabled the initiation of a number of clinical trials using this gene delivery system. Another potential benefit of AAV vectors is their ability to integrate site-specifically in the presence of Rep proteins. However, this virus is not well characterized. To obtain high level, persistent expression of the foreign gene, some problems should be solved. In this article, we will describe the advances in some fields of recombinant AAV technology that overcome certain limitations of the vector as a gene delivery system, such as the transduction efficiency, the production, the package capacity, and elimination of immune responses, as well as the applications involving these recombinant vectors for the treatment of some diseases.

Dependovirus↗

PubMed2001

In vivo DNA-protein interactions at hypersensitive site 3.5 of the human beta-globin locus control region.

Using ligation-mediated polymerase chain reaction and in vivo footprinting methods to study the status of DNA-protein interactions at hypersensitive site 3.5 (HS3.5) of the locus control region in K562 and HEL cells, we found that there was protein occupancy in vivo at HS3.5 in both cell lines and the status of DNA-protein interaction was different between K562 and HEL. These data provide direct evidence that specific nuclear factor-DNA complexes form in vivo at functionally important sequence motifs of the HS3.5 in erythroid cells. This indicates that HS3.5 may play an important role in the regulation of the beta-globin gene cluster. K562 is a human erythroleukemia cell line in which the embryonic epsilon-globin gene is predominantly expressed, while the HEL cell line expresses predominantly the fetal beta-globin genes. Thus, HS3.5 might also be involved in the regulation of developmental stage-specific expression of beta-globin genes. Our results are also consistent with the model that each hypersensitive site acts as a functional unit and HS3.5 may facilitate the formation of the HS3 functional unit.

Base Sequence↗

PubMed2000

Proper developmental control of human globin genes reproduced by transgenic mice containing a 160-kb BAC carrying the human beta-globin locus.

Four independent bacterial artificial chromosome (BAC) clones containing the human Beta-globin gene locus were obtained from a human genomic BAC library. A 160-kb clone (186D7) carrying the entire human Beta-globin locus including the Beta-globin gene family, locus control region (LCR), and 3' regulatory elements was used to transform mice. Four transgenic lines were generated by microinjecting the purified BAC DNA into the fertilized eggs. RNase protection analysis showed that the expression of human Beta-globin genes is tissue- and developmental stage-specific and the expression level is similar among the three independent transgenic lines which carry the entire human Beta-globin locus; however, no Beta-globin gene expression was detected in the transgenic mice lacking the LCR region. The results suggest that the transgenic mouse model system that we have produced and that uses BAC to study the complex human Beta-globin gene cluster is stable and reproducible. Our results also indicate that some newly characterized HSs upstream from the LCR appear not to play an important role in globin gene expression and switching, while the traditional LCR can ensure correct human Beta-globin gene expression in transgenic mice. The BAC-mediated transgenic system can be used for further studies to determine which kinds of cis-acting elements are included in regulating the developmental timing and the level of human Beta-globin gene expression.

Animals↗

PubMed2000

The usefulness of cystoscopy in the staging of cervical cancer.

OBJECTIVE: The aim of this study was to clarify the usefulness of cystoscopy in the staging of cervical cancer and to evaluate the clinical indications for performing ureteric catheterization to rule out ureteral obstruction in cervical cancer. METHODS: Both rigid cystoscopy and CT were performed before treatment in patients with cervical cancer of FIGO stage IB or greater. Cystoscopically directed biopsy specimens were taken from all areas in the bladder which were suspected of cancerous development. If a jet of urine spurting from each ureteral orifice was not found, a ureteric catheter was inserted into the orifice to rule out ureteral obstruction. The cystoscopic findings were compared with a CT examination. RESULTS: A total of 100 patients were included in the study (mean age 59 years). There were 30 stage IB cancers, 20 stage IIA, 17 stage IIB, 5 stage IIIA, 18 stage IIIB, and 10 stage IV. A total of 90 patients had squamous cell carcinomas and 10 had adenocarcinomas. Cystoscopy identified 8 patients with bladder invasion including 1 stage IIIA, 2 stage IIIB, and 5 stage IV. All of these patients had CT indication of possible invasion. CT indication of possible invasion was proved to be false by cystoscopy in 2 patients. Both the sensitivity and the negative predictive value of CT for bladder invasion were 100%. Of the 14 patients in whom ureteral obstruction was diagnosed by ureteric catheterization, 11 cases were indicated by CT scan, but for the other 3 patients CT found no significant ureteral obstruction. CONCLUSIONS: The results of this study suggest that cystoscopy is indicated only in cervical cancer patients for whom CT examination indicates possible bladder invasion. In addition, the results suggest that placement of ureteric catheterization using cystoscopy to rule out ureteral obstruction is not indicated in the staging of cervical cancer.

Adenocarcinoma↗

PubMed2000

Comparison of two kinds of methods to determine the titer of recombinant retrovirus containing beta-globin gene based on G418 selection.

Four recombinant retrovirus (RV) vectors containing human beta-globin gene and regulatory elements were constructed. To determine the titers of recombinant RV from corresponding producer cell lines, we compared two kinds of method (the simple and the conventional) based on G418 resistance, which is conferred by neo gene of RV vector. The results demonstrated that the simple method shortened the selection period to 3 d instead of 10-12 d with the conventional method and reduced the amount of work; importantly, the titers determined by the simple method were not different significantly from those measured by the conventional method. It can be concluded that the simple method can be used to determine the titers of recombinant RV containing not only cDNA but also genomic DNA with introns and complex regulatory elements instead of the conventional method.

3T3 Cells↗

PubMed2000

Seroprevalence of Coxiella burnetii infection in southern Taiwan.

BACKGROUND AND PURPOSE: The emergence of infection with Coxiella burnetii, the causative organism of Q fever, has been only recently recognized in Taiwan. Several cases of acute Q fever infection have been described, but the prevalence of antibodies to C. burnetii in the general population in Taiwan has not been reported. Thus, we studied the seroprevalence of C. burnetii infection in southern Taiwan. METHODS: We conducted a retrospective serosurvey to examine the prevalence of C. burnetii infection among subjects admitted to a rural hospital in Taiwan for various reasons, and among presumably healthy attendees of a routine physical examination clinic of an urban public hospital. The diagnosis of C. burnetii infection required the presence of antibodies to both phase I and II antigens (titer > or = 1:16) or only to phase II antigens (titer > or = 1:256), as detected by indirect immunofluorescence assay. RESULTS: The prevalence of C. burnetii infection was 4.2% in both the in-patient (15/357) and physical examination participant (11/259) populations. None of these subjects had signs compatible with acute Q fever (febrile illness within the past 3 months). The antibody prevalence rate was higher in males than in females, and peaked in persons aged 61 to 70 years. CONCLUSIONS: These data suggest that C. burnetii infection is not rare in southern Taiwan and does not cause clinical symptoms in all infected patients.

Adolescent↗