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Biomedical subjects

C H Chang

Publications and source records attributed to C H Chang.

At least 109 records · Page 6Linked to original sources
PubMed2000

Interpretation of a full-information item-level factor analysis of the MMPI-2: normative sampling and nonpathognomonic descriptors.

An exploratory item-level full-information factor analysis was performed on the normative sample for the MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989). This method of factor analysis, developed by Schilling and Bock (Bock & Schilling, 1997) and based on item response theory, works directly with the response patterns and avoids the artifacts associated with phi coefficients and tetrachoric coefficients. Promax rotation of the factor solution organizes the clinical scale items into 10 factors that we labeled Distrust, Self-Doubt, Fitness, Serenity, Rebelliousness, Instrumentality, Irritability, Artistry, Sociability, and Self-Reliance. A comparison was made to the results of Johnson, Butcher, Null, and Johnson (1984), who performed a principal-component analysis on an item set of 550 items from the previous version of the MMPI (Hathaway & McKinley, 1943). Along with version changes and sampling differences, the essential differences between Johnson et al.'s results and ours may be attributed to differences between the Schilling and Bock method, which uses all information in the item responses, and the principal-component analysis, which uses the partial information contained in pairwise correlation coefficients. This study included 518 of the complete 567 items of the MMPI-2, versus Johnson et al.'s retention of 309 of the initially included 550 items of the previous MMPI. The full-information analysis retained all 518 initially included items and more evenly distributed the items over the 10 resulting factors, all sharply defined by their highest loading items and easy to interpret. Sampling effects and factor label considerations are discussed, along with recommendations for research that would validate the clinical utility of the implied scales for describing normal personality profiles. The full-information procedure provides for Bayes estimation of scores on these scales.

Adolescent↗
PubMed2000

Development and validation of the satisfaction with pharmacist scale.

To assess patients' satisfaction with pharmacists, seven questions were developed with semistructured input from 5 pharmacy practice faculty members and 11 patients with cancer. The study identified 1617 English- and Spanish-speaking patients with cancer or human immunodeficiency virus infection or acquired immunodeficiency syndrome who participated in a multisite validation of the Functional Assessment of Cancer Therapy Scale. Of these, 1124 had seen a pharmacist in the past 7 days and therefore were eligible; 608 spoke English and 516 Spanish. The seven items on the Satisfaction with Pharmacist (SWiP) scale were rated on a five-point Likert scale (0 = not at all to 4 = very much). The reliability of the English and Spanish versions was evaluated by Cronbach's alpha coefficients. The unidimensionality and construct validity were analyzed with the Rasch rating scale model. The alpha coefficients for the English and Spanish versions were 0.90 and 0.92, respectively. Rasch analyses of item responses showed that none of the items in either language was a misfit, which supported their ability to measure a unidimensional construct. Item difficulty plots revealed that no item exhibited differential functioning, indicating that the items performed the same in both languages. The SWiP scale has reliable and valid psychometric properties in English and Spanish and can be used to document the value of the pharmacist-patient relationship. It is easy to administer and is ready for further use and evaluation to determine and document outcomes of pharmaceutical care.

Adult↗
PubMed2000

Cholesterol crystal embolization causing acute renal failure.

Acute renal failure due to cholesterol embolization is a complication of severe generalized arteriosclerotic disease. It occurs spontaneously, or more often, as a complication of major medical or surgical procedures such as angiography and vascular surgery. The demonstration of characteristic cholesterol crystals in tissue biopsy specimens is a pathognomonic finding. However, renal cholesterol embolism may be clinically diagnosed when renal failure develops after known inciting factors or together with systemic manifestations of atheromatous embolization such as lower extremity livedo reticularis and focal digital ischemia. We report two cases of acute renal failure in which cholesterol embolization was found in skin and renal biopsies. One patient's renal function stabilized, but not to the basal level and the other patient developed end-stage renal disease.

Acute Kidney Injury↗
PubMed2000

Composite graft tear and aortico-left ventricular tunnel after aortic root replacement using Cabrol's technique.

Woven graft tera is a very rare complication after aortic root replacement using Cabrol's technique. In this report, we present a 40-year-old man with aortic annular ectasia and severe aortic regurgitation who underwent four revisional aortic valve operations because of recurrent paravalvular leakage after valve repair and/or replacement. The Bentall operation with translocated aortic valve and Cabrol's coronary artery anastomosis were performed in the fifth operation, because of progressive dilatation of the aortic root and ascending aorta. Unfortunately, aortico-ventricular tunnel developed 2 years after aortic root replacement using Cabrol's technique. Graft tear and proximal anastomotic leakage were found to be the cause of the tunnel during the sixth operation. The patient died of myocardial failure 8 days after the seventh aortic root replacement operation. The devastating result of this complication should alert cardiovascular surgeons to the possibility of graft failure after the Bentall operation.

Adult↗
PubMed2000

Ipsilateral distal radius and scaphoid fractures.

Simultaneous fractures of the distal radius and scaphoid are uncommon. Previous reports have outlined a variety of treatment methods for this condition. We describe the results in eight patients with simultaneous fractures of the distal radius and scaphoid, who were treated at National Taiwan University Hospital from 1987 to 1998. Treatments for the distal radius fractures included pin-in-cast in one patient, casting in one, external fixation in one, external fixation after pinning in three, and open reduction with internal fixation in two. All scaphoid fractures occurred at the scaphoid waist, and were treated with long-arm thumb spica in three patients, Herbert screw fixation in two, and percutaneous pinning in three. All of the fractures united, and none of the patients developed scaphoid avascular necrosis. One patient suffered from superficial radial nerve injury during external fixation. The functional results of the wrist were good in five patients and fair in three. To prevent the possible over-distraction of the scaphoid fracture, fixation of the scaphoid should be performed if a distraction force is to be applied during the treatment of the distal radius fracture. If no distraction force is to be applied, a thumb spica may provide adequate fixation for the scaphoid fracture.

Adult↗
PubMed2000

Risk factors of deep sternal wound infections in coronary artery bypass graft surgery.

BACKGROUND: Major infections of sternal wounds after coronary artery bypass graft surgery (CABG) occur infrequently, but when they do, they contribute substantial morbidity and mortality. We identified significant risk factors of deep sternal wound infection (DSWI) following CABG and hoped to plan prophylactic measures for high risk patients in order to reduce the incidence of infection. METHODS: From 1996 to 1997, a total of 620 patients received CABG at a medical center in Taiwan. The surgical wound was examined every day. Wound infections were defined and classified according to Centers for Diseases Control (CDC) definitions. DSWI were defined as those involving the mediastinum, bone or cartilage, and infections beneath the subcutaneous tissue. Several risk factors were analyzed. RESULTS: We identified 17 (2.7%) DSWI. Univariate analysis indicated that ASA scores, surgical risk index, surgeon, postoperative low cardiac output, re-operation for bleeding, re-wiring of sternum, length of postoperative stay in the intensive care unit, postoperative duration of mechanical ventilation, operation time, duration of cardiopulmonary bypass. Independent predictors by multivariate logistic regression analysis were re-operation for bleeding and operation time. A total of 16 organisms were isolated among 14 patients. Staphylococcus accounted for most isolates (93.8%) and the most of them were methicillin-resistant (80%). CONCLUSIONS: Re-operation for bleeding and operation time were the independent predictors.

Aged↗
PubMed2000

Correlation between clinical activity score and thyroid autoantibodies in patients with thyroid ophthalmopathy.

To investigate the relation between clinical activity score (CAS) and thyroid autoantibodies of thyroid ophthalmopathy, we measured the level of TSH receptor antibody (TRAb), antithyroglobulin antibody (ATA), and antimicrosomal antibody (AMA) in 41 patients with thyroid ophthalmopathy. The results of thyroid autoantibodies level were compared with CAS. Under the multiple regression and correlation analysis among CAS and the levels of TRAb, ATA, and AMA, no correlation was shown in this study. In conclusion, there is no correlation of thyroid ophthalmopathy among CAS and the levels of TRAb, ATA, and AMA in our study. If we use these three kinds of thyroid autoantibodies to match the activity of thyroid ophthalmopathy, it seems to be inappropriate. Further search of other simplified index to reflect the activity of ophthalmopathy should be encouraged.

Adult↗
PubMed1999

Exon 4-encoded acidic domain in the epithelium-restricted Ets factor, ESX, confers potent transactivating capacity and binds to TATA-binding protein (TBP).

The Ets gene family has a complex evolutionary history with many family members known to regulate genetic programs essential for differentiation and development, and some known for their involvement in human tumorigenesis. To understand the biological properties associated with a recently described epithelium-restricted Ets factor ESX, an 11 kb fragment from the 1q32.2 genomically localized human gene was cloned and analysed. Upstream of the ESX promoter region in this genomic fragment lies the terminal exon of a newly identified gene that encodes a ubiquitin-conjugating enzyme variant, UEV-1. Tissues expressing ESX produce a primary 2.2 kb transcript along with a 4.1 kb secondary transcript arising by alternate poly(A) site selection and uniquely recognized by a genomic probe from the 3' terminal region of the 11 kb clone. Endogenous expression of ESX results in a 42 kDa nuclear protein having fivefold greater affinity for the chromatin-nuclear matrix compartment as compared to other endogenous transcription factors like AP-2 and the homologous Ets factor, ELF-1. Exon mapping of the modular structure inferred from ESX cDNA and construction of GAL4(DBD)-ESX expression constructs were used to identify a transactivating domain encoded by exon 4 having comparable potency to the acidic transactivation domain of the viral transcription factor, VP16. This exon 4-encoded 31 amino acid domain in ESX was shown by mutation and deletion analysis to possess a 13 residue acidic transactivation core which, based on modeling and circular dichroism analysis, is predicted to form an amphipathic alpha-helical secondary structure. Using recombinant GST-ESX (exon 4) fusion proteins in an in vitro pull-down assay, this ESX transactivation domain was shown to bind specifically to one component of the general transcription machinery, TATA-binding protein (TBP). Transient transfection experiments confirmed the ability of this TBP-binding transactivation domain in ESX to squelch heterologous promoters independent of any promoter binding as efficiently as the transactivation domain from VP16.

Amino Acid Sequence↗
PubMed1999

Haloalkane dehalogenases: steady-state kinetics and halide inhibition.

The substrate specificities and product inhibition patterns of haloalkane dehalogenases from Xanthobacter autotrophicus GJ10 (XaDHL) and Rhodococcus rhodochrous (RrDHL) have been compared using a pH-indicator dye assay. In contrast to XaDHL, RrDHL is efficient toward secondary alkyl halides. Using steady-state kinetics, we have shown that halides are uncompetitive inhibitors of XaDHL with 1, 2-dichloroethane as the varied substrate at pH 8.2 (Cl-, Kii = 19 +/- 0.91; Br-, Kii = 2.5 +/- 0.19 mM; I-, Kii = 4.1 +/- 0.43 mM). Because they are uncompetitive with the substrate, halide ions do not bind to the free form of the enzyme; therefore, halide ions cannot be the last product released from the enzyme. The Kii for chloride was pH dependent and decreased more than 20-fold from 61 mM at pH 8.9 to 2.9 mM at pH 6.5. The pH dependence of 1/Kii showed simple titration behavior that fit to a pKa of approximately 7.5. The kcat was maximal at pH 8.2 and decreased at lower pH. A titration of kcat versus pH also fits to a pKa of approximately 7.5. Taken together, these data suggest that chloride binding and kcat are affected by the same ionizable group, likely the imidazole of a histidyl residue. In contrast, halides do not inhibit RrDHL. The Rhodococcus enzyme does not contain a tryptophan corresponding to W175 of XaDHL, which has been implicated in halide ion binding. The site-directed mutants W175F and W175Y of XaDHL were prepared and tested for halide ion inhibition. Halides do not inhibit either W175F or W175Y XaDHL.

Amino Acid Sequence↗
PubMed1999

Porcine pancreatic phospholipase A2 stimulates secretin release from secretin-producing cells.

We have isolated, from canine pancreatic juice, two 14-kDa proteins with secretin-releasing activity that had N-terminal sequence homology with canine pancreatic phospholipase A2 (PLA2). In this study we have obtained evidence that secretin-releasing activity is an intrinsic property of pancreatic PLA2. Porcine pancreatic PLA2 from Sigma or Boehringer Mannheim was fractionated into several peaks by reverse phase high performance liquid chromatography. They were tested for stimulation of secretin release from murine neuroendocrine intestinal tumor cell line STC-1 and secretin cells enriched mucosal cell preparations isolated from rat upper small intestine. Each enzyme preparation was found to contain several components of secretin-releasing activity. Each bioactive fraction was purified to homogeneity by rechromatography and then subjected to mass spectral analysis and assays of PLA2 and secretin-releasing activities. It was found that the fraction with highest enzymatic activity also had the highest secretin-releasing activity and the same Mr as porcine pancreatic PLA2. Moreover, it also had the same N-terminal amino acid sequence (up to 30 residues determined) as that of porcine pancreatic PLA2, suggesting that it was identical to the enzyme. Purified porcine pancreatic PLA2 also stimulated secretin release concentration-dependently from both STC-1 cells and a mucosal cell preparation enriched in secretin-containing endocrine cells isolated from rat duodenum. Abolishment of the enzymatic activity by pretreatment with bromophenacyl bromide did not affect its secretin-releasing activity. The stimulatory effect of purified pancreatic PLA2 on secretin secretion from STC-1 cells was inhibited by an L-type Ca2+ channel blocker, by down-regulation of protein kinase C or by pretreatment of the cell with pertussis toxin. It is concluded that porcine pancreatic PLA2 possesses an intrinsic secretin-releasing activity that was independent of its enzymatic activity. This action is pertussis toxin-sensitive and is in part dependent on Ca2+ influx through the L-type channel and activation of protein kinase C.

Animals↗
PubMed1999

Pancreatic infiltration but not diabetes occurs in the relative absence of MHC class II-restricted CD4 T cells: studies using NOD/CIITA-deficient mice.

The NOD (nonobese diabetic) mouse is a good animal model for human IDDM. MHC class II-restricted CD4 T cells are necessary for the onset of diabetes in NOD mice. Here, we demonstrate that NOD mice lacking the CIITA (class II transactivator) molecule, and hence deficient in MHC class II expression and peripheral CD4 T cells, show significant pancreatic infiltration but do not develop diabetes. CD4 T cell deficiency, then, does not prevent initial pancreatic infiltration, but does stop progression to insulitis. Adoptive transfer studies show that the paucity of CD4 T cells in NOD-CIITA knockout mice is responsible for the absence of diabetes, since the CD8 T cell and B cell compartments are functional. An autoaggressive CD8+ T cell clone can, however, transfer diabetes in CIITA knockout recipient mice without CD4 T cell help, albeit with some delay compared with that in CIITA-sufficient recipients. This highlights the fact that a high number of in vitro activated autoaggressive CD8 T cells can over-ride the requirement for CD4 T cell help for the onset of diabetes.

Adoptive Transfer↗
PubMed1999

Immature teratomas of the genital tract in older women.

We report the clinicopathologic features of three women, 40 years of age or older, with malignant genital tract immature teratomas. All had FIGO stage III, grade II or grade III tumors. One tumor arose from the fallopian tube, the second from the ovary, and the third involved the cortical surfaces of both ovaries with minimal parenchymal involvement. The tumors weighed 1700, 5660, and 330 g and had histologic features similar to those generally seen in younger women. Two of the women died within 1 year of diagnosis. Interval growth of tumor after treatment with chemotherapy was documented in the third patient; she was reexplored and all of the excised tumor was composed of mature tissues. These cases affirm that, although rare, malignant germ cell tumors can occur in older peri- or postmenopausal women.

Adult↗
PubMed1999

Thoracoscopic surgery for spontaneous pneumothorax.

Spontaneous pneumothorax in apparently healthy individuals is a relatively common occurrence. The management of patients with spontaneous pneumothorax remains controversial. With the advances in thoracoscopic techniques and instrumentation, video-assisted thoracic surgery (VATS) is now accepted by many as the procedure of choice for surgical treatment of spontaneous pneumothorax. We report our combined experience with 757 patients who suffered from recurrent or persistent spontaneous pneumothorax treated by VATS over a 5-year period. Surgical indications included persistent air leak (n = 165), recurrence (n = 325), radiologically demonstrated huge bulla (n = 12), spontaneous hemopneumothorax (n = 13), incomplete expansion of the lung (n = 212), and bilateral involvement (n = 30). Several surgical procedures were undertaken, based on the thoracoscopic findings: endoscopic stapled bullectomy (n = 312), argon beam coagulation (n = 6), endoscopic suturing (n = 52), and endoloop ligation (n = 352). In 49 cases, mechanical or chemical pleurodesis was the only procedure performed. There were no mortalities or intraoperative hazards. Complications consisted of wound infections (n = 16), localized empyema (n = 2), chest wall bleeding (n = 1), and persistent air leaks (bulla type III) (n = 31). The median duration of the operation was 55 minutes (15-160 minutes), and the average postoperative hospital stay was 4.5 days (range 0-27 days). There were 16 recurrences (2.1%), after a mean follow-up of 30 months (range 1-60 months). Seven patients had recurrence from 9 to 17 months after stapled bullectomy. All the remaining patients had recurrence after failed pleurodesis. On the basis of our results, we conclude that video-assisted thoracoscopic management allows effective, safe performance of standard surgical procedures, avoiding a formal thoracotomy incision. We consider thoracoscopy the treatment of choice for patients with pneumothorax requiring surgical therapy.

Adolescent↗
PubMed1999

The use of multiplane transesophageal echocardiography to evaluate residual patent ductus arteriosus during video-assisted thoracoscopy in adults.

BACKGROUND: Video-assisted thoracoscopic surgery (VATS) has emerged as an innovative and popular procedure for interruption of patent ductus arteriosus (PDA), while intraoperative transesophageal echocardiography (TEE) has proven to be an effective monitor in the evaluation of residual patency. Previous reports on the adequacy of surgical interruption of PDA under VATS and TEE are available for pediatric patients, but only limited information is available for adults with PDA. MATEIALS AND METHODS: Between August 1995 and October 1997, we monitored 35 adult patients undergoing PDA interruption via VATS with Hewlett-Packard color Doppler multiplane TEE throughout the procedure. The average PDA diameter was 10.2 +/- 1.8 mm. All the PDA were completely ligated. RESULTS: Thirty-two patients showed no ductal flow after double ligation. In the other three patients, residual flow was detected intraoperatively after double ligation, but it was quickly abolished by the third ligation. One patient showed faint ductal flow by transthoracic echocardiography at postoperative follow-up, but no reintervention was needed. CONCLUSIONS: Our study showed that, with the refinement of adult PDA interruption via VATS, intraoperative multiplane TEE provides higher resolution for direct evaluation of the entire course of PDA ligation without interrupting the surgical procedure and minimizes the incidence of complications.

Adult↗
PubMed1999

Microvascular prefabricated free skin flaps for esophageal reconstruction in difficult patients.

BACKGROUND: Reconstruction of the esophagus for complicated benign stricture or after resection of malignant lesion is still a challenge for surgeons. When abdominal viscera cannot be used, skin flaps are selected for esophageal reconstruction. However, skin flaps for esophageal reconstruction are notorious for leakage, and have not been widely accepted. Prefabrication before microvascular transfer to its final site can improve the result of esophageal reconstruction when skin flaps are used. METHODS: Eight patients with complicated corrosive esophagitis had been treated with prefabricated skin flaps for esophageal reconstruction. The procedures are described in detail. RESULTS: All patients healed well without leakage. The barium study showed smooth passage. There was no dysphasia or regurgitation after education. Pulmonary complication happened in only 1 patient. Revision for the distal anastomosis was required in 1 patient due to narrowing. When the skin tube is long, the patients need water (or soup) to facilitate swallowing and occasionally use their hand to help the food passage. This method has the following advantages: (1) healing of the long suture line before transfer to withstand the intestinal juice; (2) reliable viability in the distal part of the flap, especially when an extended length of the flap is required; (3) more length of stable tissue for two-layered, tension-free anastomosis at the junction of skin and gastrointestinal mucosa to prevent leakage; and (4) the flap can be placed in the substernal position to meet the aesthetic requirement of young patients. The disadvantage was the staged operations. However, after prefabrication the transfer becomes safe and free of leakage. The overall morbidity is minimal. CONCLUSIONS: In rare situations when skin flaps are used for esophageal reconstruction, prefabrication provides advantages over conventional one-stage methods, although it needs additional procedures. This method is a combination of conventional technique and microsurgery.

Adult↗
PubMed1999

"I" ministernotomy for aortic valve replacement.

BACKGROUND: Minimally invasive surgical approaches have been applied recently in the management of valvular heart disease. In this report, we reviewed our preliminary experience of minimally invasive aortic valve replacement. METHODS: Eighteen patients were operated on by means of an "I" ministernotomy, and 16 patients were operated on by means of a full median sternotomy during the same period. There was no difference between these two groups in term of age, sex, and preoperative left ventricular ejection fraction. In patients of the ministernotomy group, the operations were approached through an "I" median sternal split, from the second to the fifth intercostal space, 8 to 10 cm in length, with transverse division. Cardiopulmonary bypass was established through aorto-right atrial cannulation with aortic cross-clamping and antegrade or retrograde delivery of blood cardioplegia. RESULTS: Under direct vision, aortic valve replacement was performed successfully in patients of both groups. The duration of cardiopulmonary bypass time and aortic cross-clamp time was significantly longer in the ministernotomy group than in the full sternotomy group. However, the length of incision, duration of endotracheal intubation, intensive care unit stay, pain score, postoperative length of stay, and return to normal activity interval were significantly shorter and lower in patients of the ministernotomy group than in those of the full sternotomy group. All patients recovered from the operation rapidly. Follow-up was complete in all patients with no late complications. Echocardiographic examination showed good function of aortic prostheses. CONCLUSIONS: Our experience demonstrates that the "I" ministernotomy provides good exposure, reduced wound pain, enhanced recovery, shortened hospital stay, and good cosmetic healing. It may be a good alternative for surgical correction of aortic valve lesions.

Adult↗
PubMed1999

Sensitization of stereotyped behavior to amphetamine is context and response dependent.

The present study was designed to determine whether the environmental context in which amphetamine is administered plays a role in the development of sensitization to the stereotyped behavioral effects of amphetamine in mice. In male CF-1 mice, the dose-response curve for stereotyped behavior elicited by amphetamine was shifted 1.9-fold to the left 48 h after pretreatment with 14 mg/kg amphetamine. Behavioral sensitization only developed in mice that were pretreated in the same or a similar environment as that of the test environment. In addition, when mice were placed in an environment that attenuated the acute expression of stereotyped behavior elicited by the pretreatment dose of amphetamine, sensitization never developed. A further experiment showed that 96% of the mice that expressed stereotypy after the ED50 pretreatment dose of 10 mg/kg amphetamine showed a stereotyped behavioral response to the lesser dose of 7 mg/kg 48 h later, indicating sensitization. In contrast, mice that did not express stereotypy after the ED50 dose of amphetamine failed to show a significant stereotyped behavioral response to amphetamine challenge compared to vehicle-pretreated controls. Therefore, the results indicate that preexposure to a single high dose of amphetamine produces context- and response-dependent sensitization to amphetamine-induced stereotyped behavior.

Animals↗