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Biomedical subjects

David Chao

Publications and source records attributed to David Chao.

13 recordsLinked to original sources
PubMed2007

Surgical treatment of type II floating knee: comparisons of the results of type IIA and type IIB floating knee.

The prognosis of type II floating knee injuries was not as good as that of type I. Our purpose is to clarify the factors affecting the outcome of type II floating knee injuries. Thirty-five patients (36 limbs) with type II floating knee injury were studied with a mean follow-up of 52 months (26-96). Blake and McBryde had classified these injuries into type I for pure diaphyseal (true type) fracture and type II if the intra-articular involvements are one or more including hip, knee and ankle joints (variant type). According to this classification, we divided these patients into two groups depending on whether their knees were involved or not. Those cases with intra-articular knee involvement were classified as type IIA, while those without intra-articular knee involvement were classified as type IIB. Of the 36 cases, 21 were classified as type IIA and 15 were type IIB. The functional outcomes of these injuries were evaluated by using the criteria of Karlström and Olerud and analyzed with multivariate analysis. After multivariate analysis with logistic regression, we show the following results: first, the poor functional outcome of type II floating knee is contributed by type IIA. Second, the type IIA group has severer femoral open fracture grading (P = 0.027) and poorer functional outcome (P = 0.009) than type IIB. Third, the significant contributing factors to final outcome are the group (P = 0.013) and the fixation time after injury in femur (P = 0.015). Intra-articular knee involvement is the most important factor contributing to poor outcome of type II floating knee. The treatment of floating knee injuries with intra-articular knee involvement is still difficult. Further efforts to search better methods of treatment are required for these complex injuries in the future.

Adolescent↗
PubMed2006

New insights into the pathological mechanisms of cerebrotendinous xanthomatosis in the Taiwanese using genomic and proteomic tools.

Cerebrotendinous xanthomatosis (CTX) is an autosomal recessive lipid-storage disorder caused by a deficiency of the mitochondrial sterol 27-hydroxylase. Genetic analysis utilizing SSCP and direct DNA sequencing identified a new mutation. One base-pair of cytosine was deleted at codon 326 on exon 2 of CYP27 in all CTX patients while their father was heterozygotic. This novel point deletion predicts a frameshift in mRNA (Pro(102) -->Leu) and results in the appearance of a premature termination codon (TGA) to substitute for Val(106) (GTG). To characterize the pathological mechanism of CTX patients, the protein profiles of serum and leukocytes extracted from these subjects were presented by means of proteomic technologies including 2-DE and MALDI-TOF analysis. According to the results, the amount of vinculin, ABP-280, talin and vimentin in leukocytes of CTX patients had changed significantly, reflecting the changes in membrane dynamics concerning cholestanol accumulation. The expression of target proteins in CTX patients and control was further verified by western blotting which indicated the same tendency as 2-DE data. This is the first paper to integrate both genomic and proteomic concepts for analyzing the possible mechanism of CTX and provides more information for related study in the future.

Amino Acid Sequence↗
PubMed2006

Postoperative pain management for arthroscopic shoulder surgery: interscalene block versus patient-controlled infusion of 0.25% bupivicaine.

We compared an interscalene block with a patient-controlled regional anesthesia device (Pain Care 2000; Breg, Inc, Vista, Calif) for pain management after outpatient arthroscopic shoulder surgery (subacromial decompression as principal procedure). The 41 patients in this prospective study were randomized to receive either the block or the device. During the postoperative period, all patients in both groups received standardized oral medications and continuous cold therapy and used continuous passive motion machines. Patients were given diaries and instruction in making entries upon waking and before retiring on postoperative days 1, 2, 3, 5, and 10. Data collected were number of pain medications used each day; number of nighttime awakenings; and subjective pain, activity, and quality-of-life levels rated on a visual analog scale. All data were statistically analyzed with the Mann-Whitney test. Compared with patients using the block, patients using the device awoke significantly fewer times the first night after surgery (P = .023), were significantly more active during postoperative days 1 and 2 (Ps = .018, .042), and took significantly fewer pain medications on postoperative day 2 (P = .034). On all other measures, results were equivalent or were better with the device, though these findings were not statistically significant. Patient-controlled subacromial infusion of bupivicaine is an effective alternative to interscalene block for outpatient pain management after arthroscopic shoulder surgery.

Adult↗
PubMed2005

Neurocognitive functioning in pediatric human immunodeficiency virus infection: effects of combined therapy.

OBJECTIVES: To assess the impact of combination antiretroviral therapy on neurocognitive outcomes in perinatally human immunodeficiency virus (HIV)-infected patients and to determine if CD4 percentage and plasma HIV-1 RNA level (viral load) are predictive of future neurocognitive function. DESIGN: Retrospective cohort study. SETTING: An HIV-dedicated urban care center. PARTICIPANTS: One hundred forty-six perinatally HIV-infected children born between June 1990 and May 2003 with at least 1 neurocognitive evaluation. MAIN OUTCOME MEASURES: Neurocognitive standard testing scores as well as diagnosis of progressive encephalopathy, probable progressive encephalopathy, or static encephalopathy. RESULTS: The prevalence of progressive encephalopathy has decreased in children born prior to 1996 (period 1) compared with those born after 1996 (period 2) from 29.6% to 12.1% (P = .049). The prevalence of all progressive encephalopathy and static encephalopathy decreased from 40.7% to 18.2% in period 1 vs 2 (P = .02). For those diagnosed as neurocognitively healthy, neurocognitive scores remained stable over time with a mean (SD) standard score of 89.6 (11.8) at first evaluation compared with 91.9 (11.93) at most recent evaluation. The most recent mean (SD) standard score increased from 82.3 (18) to 87.2 (10.49) in period 1 vs period 2 (P = .001). A weak association was found between both the mean viral load (P = .06) and CD4 percentage (P<.001) and neurocognitive testing score 6 months later. CONCLUSIONS: Since 1996, fewer children have been diagnosed with progressive encephalopathy, and neurocognitive functioning is preserved over time in those deemed neurocognitively healthy at entry. Viral load and CD4 percentage are marginally predictive of future changes in neurocognitive standard scores. These data support the observation that combination antiretroviral therapy is associated with improved neurocognitive outcomes in children with perinatally acquired HIV infection.

AIDS Dementia Complex↗
PubMed2004

Surgical treatment for ipsilateral fractures of the hip and femoral shaft.

Concomitant ipsilateral femoral shaft and neck fractures are difficult to treat. There is still no consensus on the optimal treatment of these complex fractures. Forty-seven patients with these complex fractures were treated in Kaohsiung Medical University Hospital between the periods of 1982 and 1998. Our standard treatment protocol is plate fixation for femoral shaft fracture and lag screw or dynamic hip screw (DHS) fixation for hip fracture. Among 42 cases treated with this protocol, 34 were males and 8 were females with an average age of 36 years and average follow-up period of 55 months. We divided hip fractures into two groups: femoral neck fracture as group I and intertrochanteric fracture as group II. There were no non-union and osteonecrosis of the hip in either group. One diaphyseal non-union was observed in group I and four in group II. There were 92 and 76% good functional results in groups I and II, respectively. The result shows that our standard method can yield a reliable outcome in group I, but not in group II.

Activities of Daily Living↗
PubMed2004

Allogeneic hematopoietic stem-cell transplantation: the next generation of therapy for metastatic renal cell cancer.

The management of metastatic renal cell carcinoma (mRCC) remains a therapeutic challenge; less than 10% of patients survive for longer than 5 years. The resistance of renal cancer to chemotherapy may be explained by high levels of the multidrug resistance gene, MDR1. Immune-based treatments for renal cancer have been explored because of their unusual susceptibility to immunological assault. However, response rates to cytokines such as interleukin-2 and interferon-alpha have ranged from only 10% to 20%, prompting other immunotherapy approaches, such as allogeneic stem-cell transplantation, to be investigated. Several clinical trials have provided evidence of partial or complete disease regression in refractory mRCC following nonmyeloablative stem-cell transplantation. This effect is because of a donor antimalignancy effect mediated by immunocompetent donor T cells, called graft-versus-tumor effect. Unfortunately, less than 30% of patients who could have this procedure will have a human-leukocyte-antigen-compatible sibling, and attention is focusing on alternative donors such as matched unrelated donors and partially mismatched related donors. Despite the improved safety of nonmyeloablative conditioning regimens, transplant-related toxic effects (particularly graft-versus-host disease) remain obstacles to the safe and effective use of this treatment. Regardless of these limitations, innovative approaches have attempted to harness the potential of the graft-versus-tumor effect in mRCC and other solid tumors.

Carcinoma, Renal Cell↗
PubMed2004

Dying and defibrillation: a shocking experience.

Palliative Care physicians are frequently involved in the care of patients with significant comorbidity and often have to take coexisting conditions into account when treating patients. An example of an area in which this is particularly relevant and will undoubtedly increase is presented with the case report of a patient with terminal metastatic lung carcinoma and an Implantable Cardioverter Defibrillator (ICD) in place. The role of the ICD in preventing the patient from dying comfortably is discussed, as are means of deactivating the device. We conclude that patients with ICDs and terminal disease should have the issue of deactivation addressed at the earliest possible opportunity as practical difficulties may arise in the emergency setting, especially in the nonhospital environment.

Anxiety↗
PubMed2003

Protective immunity against Toxoplasma gondii in mice induced by a chimeric protein rSAG1/2.

The aim of this study was to test the protective immunity against Toxoplasma gondii in mice induced by a chimeric protein rSAG1/2. The PCR-amplified SAG2 fragment (558 bp) digested with the restriction enzyme XhoI was inserted into the XhoI site of plasmid pGEX-6p-1, termed pGexSAG2. The PCR-amplified SAG1 fragment (1,008 bp) digested with restriction enzymes EcoRI and XhoI was cloned into the EcoRI/ XhoI sites of a separate plasmid pGEX-6p-1, termed pGexSAG1. The SAG2 fragment (HindIII/HindIII) excised from pGexSAG2 was inserted into the HindIII site of pGexSAG1 and a chimeric vector constructed, pGexSAG1/2. The fusion proteins GST-SAG1/2, GST-SAG1 and GST-SAG2 were expressed in BL21 Star (DE3) Escherichia coli and purified by GSTrap FF columns. After removing the GST tag, the recombinant proteins rSAG1/2, rSAG1 and rSAG2 were independently collected and injected into different groups of mice to evaluate their protective capability. The highest proliferation of splenocytes stimulated with tachyzoite sonicate antigen (TsoAg) was observed in BALB/c mice which had received two intraperitoneal injections of rSAG1/2. Maximum production of IFN-gamma was also found in the culture supernatants of TsoAg-stimulated splenocytes from rSAG1/2-immunized mice. Finally, 73% (11/15) of mice immunized with rSAG1/2 survived at least 28 days after a lethal challenge of 1 x 10(3) live tachyzoites which killed all non-immunized mice within 10 days. Moderate survival rates were observed in mice immunized with either rSAG1 (60%) or rSAG2 (53%). These results show that the chimeric protein rSAG1/2 can elicit a Th1-associated protection against T. gondii infections in mice.

Amino Acid Sequence↗
PubMed2003

Protective immunity against Toxoplasma gondii in mice induced by the SAG2 internal image of anti-idiotype antibody.

A monoclonal antibody TGCM5 (isotype G, subclass 1, kappa light chain) against SAG2, a major surface antigen of Toxoplasma gondii tachyzoites, was produced in quantity and its Fab-containing idiotype (Id) was injected into rabbits for production of rabbit anti-Id sera. The rabbit anti-Id IgG (aId-IgG) with a SAG2 internal image was obtained by purification with a protein A column. Significant lymphocyte proliferation induced by tachyzoite lysate antigen was observed in BALB/c mice that received two injections of aId-IgG, but not in non-immunized control mice. Large amounts of gamma interferon were detected in supernatants of splenocyte cultures prepared from mice immunized with aId-IgG. Of the mice immunized with aId-IgG, 75-87.5% survived at least 28 days after a lethal challenge of 1 x 10(3) live tachyzoites, which killed all non-immunized control mice within 10 days. The results showed that the SAG2 internal image presented by aId-IgG indeed elicited a protection against the infection of T. gondii in mice.

Animals↗
PubMed2003

Low-dose IFN-gamma induces tumor MHC expression in metastatic malignant melanoma.

Specific antitumor immune responses require expression of MHC class I or II molecules on tumor cells, and MHC antigen down-regulation is a presumed tumor growth promoting mechanism. Because IFN-gamma up-regulates tumor MHC antigen expression in vitro, in this Phase II trial of an immunologically active dose and schedule we evaluated whether this was the case in vivo. Twenty-three patients with metastatic melanoma were treated with IFN-gamma 100 microg/m(2) s.c. once weekly for a maximum of 6 months. There were three complete responses, now maintained for 53, 36, and 25 months. The remainder had progressive disease. The treatment was well tolerated, with no toxicity exceeding National Cancer Institute Common Toxicity Criteria grade II. Immunohistochemical analysis of tumor biopsies during treatment was performed using monoclonal antibodies to HLA class I (W/632) and class II (CR3/43) monomorphic determinants. HLA class I was down-regulated in 2 of 19 patients pretreatment and up-regulated by IFN-gamma in both. HLA class II was down-regulated pretreatment in 14 of 18 patients and up-regulated by IFN-gamma in 6 (43%). The HLA up-regulation persisted throughout the study. IFN-gamma induced significant but short-lived up-regulation of surrogate markers of monocyte activation (serum neopterin) and class I up-regulation (serum beta-2-microglobulin) in most patients. There was no consistent relationship between surrogate marker up-regulation, tumor antigen up-regulation, and responses. The study shows that the significant immune modulation induced by IFN-gamma does not correlate with tumor responses and that the serum surrogate marker changes do not reflect tumor events. The durable and long-lived responses, clear demonstration of tumor MHC up-regulation, and low toxicity suggest that weekly IFN-gamma 100 microg/m(2) would be a useful addition to chemoimmunotherapeutic regimens.

Adult↗
PubMed2002

Haplorchis infections in intermediate hosts from a clonorchiasis endemic area in Meinung, Taiwan, Republic of China.

Snails and freshwater fish were examined from four ponds in the Meinung township in which Clonorchis sinensis was known to be endemic 18 years ago. No metacercariae were found in 478 Tilapia nilotica, whereas of 451 Ctenopharyngodon idellus examined, 16.2%, 3.3% and 0.9% were found to be infected with Haplorchis pumilio, H. taichui and Clonorchis sinensis, respectively. In addition, there were some unidentified metacercariae in 12.0% of Ctenopharyngodon idellus examined. Overall, no positive correlation between infection rates and sizes of infected fish was shown. Six species of snails were collected in this survey and two frequently-occurring snails, Melanoides tuberculata and Thiara granifera were commonly infected with H. pumilio. Reasons for the prevalence of Haplorchis species and the absence of Clonorchis sinensis in fish and snail hosts in a previously reported endemic area for human clonorchiasis are discussed.

Animals↗