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Biomedical subjects

C H Chang

Publications and source records attributed to C H Chang.

At least 235 records · Page 13Linked to original sources
PubMed1997

Fetal heart volume assessment by three-dimensional ultrasound.

Heart volume may provide important information on the status of fetal hemodynamics. However, traditionally fetal heart volume has been assessed with the erroneous assumption that the fetal heart is spherical or elliptical. With the advent of three-dimensional ultrasound, accurate assessment of organ volume has become feasible. The objectives of this study were to compare the reproducibility of two-dimensional ultrasound and three-dimensional ultrasound in the assessment of heart volume, and to test whether heart volume assessed by the traditional method of two-dimensional ultrasound equates to that assessed by three-dimensional ultrasound. If it proved to be significantly different, we aimed to find a new constant which, if incorporated into the traditional formula used to determine heart volume, would enable us to achieve more accurate volumes with two-dimensional ultrasound. In total, 50 normal singleton fetuses ranging from 20 to 30 weeks' gestation were included in the study. Both the traditional two-dimensional and the new three-dimensional volume measurements were compared. The results showed that three-dimensional ultrasound has a better reproducibility than two-dimensional ultrasound in heart volume assessment and that heart volume assessed by the traditional formula of two-dimensional ultrasound is significantly larger than that measured by three-dimensional ultrasound (p < 0.001). We therefore propose that, if the traditional two-dimensional equation is to be used, the constant for heart volume could be modified to 0.4563 (SE = 0.0153, n = 50) to achieve more accurate results. With this new constant, the heart volume derived by two-dimensional ultrasound was not found to differ from that measured by three-dimensional ultrasound. From our series, we conclude that three-dimensional ultrasound is theoretically the best method for the assessment of heart volume. However, because of the limitations of three-dimensional ultrasound (i.e. it is not routinely available, it is more expensive and more time-consuming) two-dimensional ultrasound in practical terms should be the method of choice. Although we were able to improve the accuracy of the heart volume measurements using a new constant in the traditional two-dimensional formula, the new constant will not improve variability, which can only be reduced by three-dimensional ultrasound.

Cardiac Volume↗
PubMed1997

Perceived adequacy of tangible social support and health outcomes in patients with coronary artery disease.

OBJECTIVE: Health outcomes of patients with chronic disease might be influenced by assistance from others in performing daily activities. We examined whether perceived adequacy of such tangible support was associated with prognosis in a cohort of patients with coronary artery disease. DESIGN: Longitudinal cohort study. SETTING/PARTICIPANTS: In spring 1993, a cohort of 1,468 patients with chronic artery disease was identified using claims data. The cohort consisted of all surviving residents of Manitoba, Canada, who had been hospitalized for acute myocardial infarction from 1991 to 1992: 820 patients completed the initial survey, and 734 completed a follow-up survey approximately 1 year later. MEASUREMENTS AND MAIN RESULTS: Adequacy of tangible support was assessed by asking if respondents needed help at home because of health problems, and whether these needs were met. We examined the association between perceived adequacy of tangible support and health outcomes at 1 year (mortality, physical function). Of 820 participants, 74% perceived no need for help, 13% had sufficient help, 9% needed more help, and 5% needed much more help; 31 patients died during follow-up. After adjustment for age and initial health status, odds ratios (95% confidence interval) for death were: sufficient help 1.8 (0.61, 5.8); need more help 3.2 (1.1, 9.4); and need much more help 6.5 (2.0, 21.6) compared with respondents with no perceived need. Decline in physical function was also linearly related to perceiving less-adequate tangible support. Sensitivity analyses indicated it is highly improbable that results were due to selection bias. CONCLUSIONS: Perceived lack of needed assistance was related to mortality and to decline in physical functioning. Adequacy of tangible support was an important prognostic factor for these patients with coronary artery disease and may be a determinant of health outcomes.

Aged↗
PubMed1997

The murine L-plastin gene promoter: identification and comparison with the human L-plastin gene promoter.

Plastins (or fimbrins) are a family of actin-binding proteins that are conserved from yeast to humans. In mammals, three tissue-specific plastin isoforms have been identified. The L isoform (L-plastin) is normally expressed only in leukocytes but is also found in >90% of neoplastic nonleukocyte human cells. Because L-plastin expression in tissue-specifically regulated in both humans and rodents, it is likely that similar mechanisms regulate L-plastin gene expression in human and rodent cells and that they could be identified by comparing the function and nucleotide sequences of the human and murine L-plastin gene promoters. Previously, we reported the isolation and characterization of the human L-plastin gene promoter. In this study, we isolated a murine L-plastin 5' end cDNA and used it as a probe to isolate several murine genomic clones. A representative clone contained 7 kb of the flanking region, 0.1 kb of the first exon, and 9.9 kb of the first intron. A continuous 1,354-bp sequence was identified around the first exon. Five transcription initiation sites were found 40 to 73 bp downstream from a perfect TATA box. Alignment of the sequence with its human counterpart revealed approximately 60% homology in a 1-kb region spanning the first exon and the flanking region. The TATA box, one ER binding site, and two ETS binding sites were completely conserved. An Sp1 binding sequence in the human promoter was partially conserved in the murine promoter but could still bind to Sp1. A second ER binding sequence, lying 5' adjacent to the TATA box in the human promoter, was conserved only at the 3' half-site in the murine promoter; the 5' half-site was changed into a potential AP1 binding site. This AP1/ER hybrid sequence was incapable of binding to ER. However, both human and murine promoters were found to function equally well in either human or murine leukocytes.

3T3 Cells↗
PubMed1997

Isolated common iliac artery occlusion secondary to atherosclerotic plaque rupture from blunt abdominal trauma: case report and review of the literature.

Traumatic isolated common iliac artery occlusion is unusual. Only rare cases of common iliac arterial injuries resulting from blunt abdominal trauma have been reported, and most of them were attributed to the seat-belt syndrome and associated with visceral organ perforation or pelvic fracture. We reported an unusual isolated common iliac artery occlusion secondary to atherosclerotic plaque rupture from blunt abdominal compressive trauma without other visceral injury. This case presented with acute limb ischemia and paralysis that was successfully treated by thromboendarterectomy. The symptoms and signs, surgical modalities, and associated injuries were reported and the literature was also reviewed.

Arterial Occlusive Diseases↗
PubMed1997

Video-assisted thoracic surgery in treatment of chest trauma.

Although the indications for video-assisted thoracic surgery (VATS) have expanded rapidly, especially in the areas of therapeutic and operative procedures, its role in the definite surgical treatment of chest trauma is not clear. From July 1994 to December 1995, 56 patients with hemothorax or posthemothorax complications resulting from chest trauma received thoracic surgery. Their ages ranged from 17 to 71 years. Mechanisms of injury included penetrating (n = 23) and blunt injury (n = 33). VATS was successfully applied in 50 patients; six patients with cardiovascular injuries (n = 4) or minor chest wall lacerations (n = 2) did not receive VATS. All patients who received VATS survived, with no morbidity. Twelve of the 50 patients treated with VATS would have otherwise had to undergo thoracotomy. Our results indicate that VATS can be safely used in hemodynamically stable patients with no cardiovascular or great vessel injury, sparing many patients the pain and morbidity associated with thoracotomy. Additionally, use of VATS may reduce the likelihood of posthemothorax complications by allowing early direct inspection of the chest wall, because VATS has a lower associated risk and can be performed with a lower index of suspicion than can standard thoracotomy.

Adolescent↗
PubMed1997

Organic delusional disorder in psychiatric in-patients: comparison with delusional disorder.

Organic delusional disorder (ODD) is rarely diagnosed in psychiatric in-patients, and may be misdiagnosed as delusional disorder (DD) from a similar clinical presentation. The aim of the present study was to investigate the characteristics of ODD and to make a comparison with those of DD patients. Patients who conformed to DSM-III-R criteria for ODD were recruited from an 8-year psychiatric in-patient database. Matching controls were DD patients admitted over the same time period. The prevalence of ODD according to DSM-III-R criteria was 0.4% of total admissions and 2.9% of organic mental disorders. Compared to DD patients, ODD patients less often had a family psychiatric history, and had an older age of onset of psychiatric disorder, longer hospital stays and lower treatment dosage of antipsychotic drugs. It is suggested that a detailed medical history and examination are needed in patients with delusion, especially in patients with a late onset of psychiatric symptoms and no family psychiatric history.

Adult↗
PubMed1997

Cdc73p and Paf1p are found in a novel RNA polymerase II-containing complex distinct from the Srbp-containing holoenzyme.

The products of the yeast CDC73 and PAF1 genes were originally identified as RNA polymerase II-associated proteins. Paf1p is a nuclear protein important for cell growth and transcriptional regulation of a subset of yeast genes. In this study we demonstrate that the product of CDC73 is a nuclear protein that interacts directly with purified RNA polymerase II in vitro. Deletion of CDC73 confers a temperature-sensitive phenotype. Combination of the cdc73 mutation with the more severe paf1 mutation does not result in an enhanced phenotype, indicating that the two proteins may function in the same cellular processes. To determine the relationship between Cdc73p and Paf1p and the recently described holoenzyme form of RNA polymerase II, we created yeast strains containing glutathione S-transferase (GST)-tagged forms of CDC73, PAF1, and TFG2 functionally replacing the chromosomal copies of the genes. Isolation of GST-tagged Cdc73p and Paf1p complexes has revealed a unique form of RNA polymerase II that contains both Cdc73p and Paf1p but lacks the Srbps found in the holoenzyme. The Cdc73p-Paf1p-RNA polymerase II-containing complex also includes Gal11p, and the general initiation factors TFIIB and TFIIF, but lacks TBP, TFIIH, and transcription elongation factor TFIIS as well as the Srbps. The Srbp-containing holoenzyme does not include either Paf1p or Cdc73p, demonstrating that these two forms of RNA polymerase II are distinct. In confirmation of the hypothesis that the two forms coexist in yeast cells, we found that a TFIIF-containing complex isolated via the GST-tagged Tfg2p construct contains both (i) the Srbps and (ii) Cdc73p and Paf1p. The Srbps and Cdc73p-Paf1p therefore appear to define two complexes with partially redundant, essential functions in the yeast cell. Using the technique of differential display, we have identified several genes whose transcripts require Cdc73p and/or Paf1p for normal levels of expression. Our analysis suggests that there are multiple RNA polymerase II-containing complexes involved in the expression of different classes of protein-coding genes.

Amino Acid Sequence↗
PubMed1997

Effect of hyperoxia on substance P expression and airway reactivity in the developing lung.

This study was undertaken to characterize changes in the tachykinin system induced by hyperoxic exposure and the potential effects on airway contractile responses. We exposed 7-day-old rat pups to either room air or hyperoxia (> 95% O2) for 7 days to assess pulmonary beta-preprotachykinin (beta-PPT) gene expression, substance P (SP) levels, and airway contractile responses to cholinergic stimulation before and after neurokinin-1 (NK1) receptor blockade. Lung beta-PPT mRNA expression, lung and tracheal SP levels, and contractile responses to exogenous acetylcholine and electrical field stimulation were measured in vitro in normoxia- and hyperoxia-exposed tracheal cylinders. Hyperoxia caused a 1.1- to 2.6-fold increase in steady-state lung beta-PPT mRNA and a 50 and 32% increase in SP levels of lung and trachea, respectively. In response to cholinergic stimulation, maximal contractile force (Emax) of hyperoxia exposed tracheal muscle was significantly higher than for normoxic controls. Addition of the SP (NK1) receptor blocker CP-99994 (10 microM) decreased sensitivity to electrical field stimulation in both hyperoxic and normoxic trachea without a significant decline in Emax. These data provide evidence for both increased SP production and enhanced maximal contractile responses of hyperoxia-exposed neonatal trachea to cholinergic stimulation. The tachykinin peptide SP does not, however, appear to play a major role in the enhanced airway reactivity associated with hyperoxic lung injury during early postnatal life.

Acetylcholine↗
PubMed1997

An alternative technique in the management of bullous emphysema. Thoracoscopic endoloop ligation of bullae.

STUDY OBJECTIVES: With the improvements in video-assisted thoracoscopic surgery, more older patients and patients with respiratory impairments are undergoing bulla ablation using new and costly technology. We evaluated the cost-effective technique of thoracoscopic endoloop ligation of bullae in patients with bullous emphysema. PATIENTS: From March 1992 through January 1996, 79 advanced age (mean age, 64 years) and oxygen dependency patients underwent thoracoscopic procedure using endoloop ligation for treatment of bullous emphysema. Clinical data were collected from chart review. Only patients with radiographically confirmed diagnosis of bullous emphysema were included in this evaluation. Thoracoscopic endoloop ligation of bulla was carried out under general anesthesia with double-lumen endotracheal tube and single-lung ventilation. RESULTS: Sixty-five patients (82%) exhibited subjective improvement in their symptom status at 3-month follow-up (from grade 2 or 3 to grade 1 or 2) according to the Modified Medical Research Council dyspnea scale. The mean duration of chest drainage was 6 days (range, 4 to 16 days). Average hospital stay was 9.5 days (range, 5 to 26 days). There was no postoperative death. A comparison of preoperative and postoperative functional evaluation was available in only 16 patients who showed an increase in FEV1 (from 0.85 to 1.02 L) and a decline in residual volume after operation. Complications include persistent airleak over 10 days in seven patients (8.9%), wound infection in three patients, and localized empyema in two patients. There was no recurrence after a mean follow-up of 21 months. CONCLUSION: These encouraging results have shown that thoracoscopic endoloop ligation of bulla has proved to be a safe, reliable, and cost-effective technique for bullous emphysema. With careful preoperative evaluation and meticulous postoperative care, many patients could be rehabilitated by endoloop litigation of the bullae.

Cost-Benefit Analysis↗
PubMed1997

The effect of valve handwheel type, operating plane, and grasping posture on peak torque strength of young men and women.

An experiment was designed to assess the factors affecting the operation of valve handwheels. Forty volunteers (20 men and 20 women) participated in this study. A nested-factorial experimental design was employed. Handwheel type (smooth, curved, or knurled rim), operating plane (sagittal, frontal, or transverse plane), grasping posture (power or precision grasp), and operating direction (clockwise or counterclockwise) were found to have significant effects on the (maximum volitional torque exertion [MVTE]). A power grasp exerted more force than did a precision grasp. A smooth-rim handwheel oriented in the frontal plane resulted in the least MVTE. Counterclockwise torque exertion was significantly greater than clockwise torque exertion, but the difference was not very large. MVTE for women (7.9 Nm) was about 66% of that for men (12.0 Nm).

Adolescent↗
PubMed1997

Comparison of the beta-glucuronidase assay and the conventional method for identification of Escherichia coli on eosin-methylene blue agar.

The purpose of this study was to compare the IMViC (indole, methyl red, Voges-Proskauer and citrate utilization) tests with the beta-glucuronidase (GUD) assay for the identification of suspect Escherichia coli on Levine's eosin-methylene blue (EMB) agar. After testing 258 suspect E. coli colonies from raw meat and meat products, 163 and 44 were found to be E. coli and non-E. coli, respectively, by both methods. Nine isolates were IMViC positive (i.e., + + - - or - + - -) but GUD negative; among these isolates, six were confirmed to be E. coli by API 20E (bioMerieux, Marcy-I'Etoile, France) with the remaining three being non-E. coli. There were 42 isolates that were IMViC negative but GUD positive; among these isolates, seven were pure E. coli cultures, 33 were mixed cultures containing E. coli, and the remaining two were Proteus spp. The sensitivities for the identification of E. coli on EMB were 80.9% (169/209) and 97.1% (203/209), respectively, by the IMViC tests and GUD assay; whereas the specificities were 93.9% (46/49) and 95.9% (47/49), respectively, by the IMViC tests and GUD assay. It is proposed that the GUD assay can be an effective alternative to the conventional IMViC tests for the identification of suspect E. coli on EMB.

Agar↗
PubMed1997

[Identification of Staphylococcus epidermidis by desferrioxamine susceptibility and trehalose fermentation tests].

The importance of coagulase-negative staphylococci, especially Staphylococcus epidermidis in clinical and nosocomial infection are recognized increasingly in recent years. A rapid and accurate identification of S. epidermidis is therefore important and necessary. A new test, susceptibility to desferrioxamine, coupled with trehalose fermentation has been recommended for the identification of this organism. However, the medium and method used are different from what has been recommended by the NCCLS. To investigate the feasibility of using the desferrioxamine susceptibility test in conjunction with the routinely used disc agar diffusion test, we employed 111 staphylococcal strains (including 51 S. epidermidis isolates, 15 S. hominis and 45 other coagulase-negative staphylococci) as test organisms, and followed the procedures recommended by the NCCLS in which Mueller-Hinton agar and standard inoculum were used. Results indicated that all strains of S. epidermidis and S. hominis were susceptible to 1 mg desferrioxamine (the diameter of the inhibition zone were 28-37 mm). The minimum inhibitory concentrations of desferrioxamine to S. epidermidis and S. hominis isolates were determined to be 125 micrograms/ml. Further differentiation of S. hominis and S. epidermidis can be made by their ability to ferment trehalose, the former could while the latter could not. We conclude that the desferrioxamine susceptibility test of coagulase-negative staphylococci can be used in conjunction with the routine disc agar diffusion method. S. epidermidis can be identified rapidly and accurately by its susceptibility to 1 mg desferrioxamine and inability to ferment trehalose.

Deferoxamine↗
PubMed1997

Use of the transurethral prostatectomy clinical path to monitor health outcomes.

PURPOSE: We evaluated the effect on cost and medical care quality of use of the transurethral prostatectomy clinical path. MATERIALS AND METHODS: Results in 100 patients treated when the transurethral prostatectomy clinical path was used were compared to those of 100 treated by the same physicians before implementation of this path. RESULTS: After implementation of the transurethral prostatectomy clinical path the length of hospital stay was significantly decreased from 5.9 to 5.0 days (p < 0.01) and Foley catheterization time was significantly decreased from 3.13 to 2.84 days (p < 0.01). Antibiotics were routinely used from the day before surgery to the day of hospital discharge as required by patient conditions. Therefore, a shorter hospital stay will significantly decrease the use of antibiotics. After implementation of the clinical path the average admission charges were decreased significantly by 17% (p < 0.01). Although some results from use of this path will not significantly affect costs, they will reflect some quality improvement. The effect of clinical path implementation on length of hospital stay between patients treated by junior and senior attending physicians was not significant. However, there was a statistically significant difference (p < 0.01) between results obtained by junior and senior attending physicians regarding average admission charges. CONCLUSIONS: Implementation of the transurethral prostatectomy clinical path can improve health care outcome by decreasing length of stay and admission charges, and improving quality of medical care, particularly for patients treated by junior attending physicians.

Aged↗
PubMed1997

Prognostic significance of altered cerebral blood flow velocity in acute head trauma.

From July 1992 to January 1993, 31 patients with acute closed head injuries underwent blood flow velocity (BFV) measurement in the middle cerebral artery by transcranial Doppler ultrasound. Eighteen patients had abnormal changes of BFV (group A) and 13 patients had normal BFV (group B). In group A, there were eight deaths (44%) and the Glasgow Outcome Scale score was 2.6 +/- 0.4 (mean +/- SEM). On admission, 14 group A patients had decreased BFV, including nine patients with evidence of early cerebral circulatory arrest (CCA). During hospitalization, eight group. A patients were diagnosed with global hyperemia, including two patients who had early CCA. Another six in group A had ultrasound recordings consistent with vasospasm, and three of these six also experienced early CCA. The renaming four patients in group A had persistently low BFV, progressing from early CCA. In group B there were two deaths (15%) and the mean Glasgow Outcome Scale score was 4.0 +/- 0.5. Group A had higher mortality (Fisher's exact test, p = 0.128) and a significantly higher rate of unfavorable functional outcome than group B. To evaluate the prognostic significance of these BFV changes, group A was subdivided into global hyperemia, vasopasm and early CCA subgroups. Both the vasospasm and early CCA subgroups had significantly lower Glasgow Coma Scale scores on admission and a higher rate of unfavorable functional outcomes than group B. All five survivors with vasospasm and/or early CCA showed ischemic morbidity on follow-up cranial computed tomography; though those with global hyperemia did not. There were no significant differences in the Glasgow Coma Scale score on admission, mortality or functional outcome between global hyperemia patients and group B patients. Global hyperemia may represent a recovery stage of impaired cerebral hemodynamics. This stage may occur transiently and has no major impact on morbidity or mortality. Vasospasm and early CCA may be closely related to ischemic complications, and may provide clinical information for selecting appropriate therapy in acute head trauma.

Acute Disease↗
PubMed1997

Surgical treatment of clubfoot deformity in arthrogryposis multiplex congenita.

Clubfoot deformity in arthrogrypotic patients is difficult to correct, and its recurrence rate is high. We retrospectively reviewed 37 clubfeet in 20 patients with arthrogryposis multiplex congenita who were treated from 1984 to 1993. There were 11 males and nine females. Bilateral involvement was seen in 17 patients and unilateral involvement in three. The mean age at the initial surgery was 2.5 years (range 4 mo to 25 yr). Soft tissue release alone was performed on 33 feet. Primary talectomy was done on both feet of one other patient. The remaining patient (two feet) underwent triple arthrodesis. Recurrence or residual deformities were seen in 18 feet with soft tissue release, among which 12 feet underwent secondary surgeries including soft tissue release, osteotomy, talectomy and connection with Ilizarov apparatus. After the secondary surgery, four of the 12 feet still had deformities. One foot had a third surgery. Achilles tendon lengthening and osteotomy. Twenty-six feet were rated as having good results (plantigrade, painless and without obvious deformity), seven were rated fair (residual deformity requiring secondary procedures) and four had poor results (persistance or recurrence of clubfoot). Despite a high recurrence rate, clubfoot deformity in arthrogrypotic patients can be treated first with radical soft tissue release when the patient is less than 1 year of age. If the foot deformity is persistant or recurs, talectomy can achieve a plantigrade foot. Triple arthrodesis should be reserved for patients with a mature bony structure.

Arthrogryposis↗
PubMed1997

Reconstruction for sequelae of septic hip in children.

Sequelae of septic hip in children may develop either due to inadequate management or neglect in the acute stage. We treated 13 patients (13 hips) with late sequelae of septic hip by reconstruction procedures, from 1985 to 1992. The mean age of the patients was 6.1 years. Their initial bony deformities were all beyond Hunka's classification type IIB. All of them had problems of hip instability and leg length discrepancy. With the intention to reestablish containment of the hip joint, open reduction, femoral osteotomy and pelvic osteotomy were performed. Four patients, all beyond Hunka type IV, had secondary surgery for hip resubluxation. Leg length discrepancies were corrected by valgus osteotomy and limb lengthening. At an average follow-up of 6.3 years, all remodeled hips were stable. Early reconstruction is recommended to stabilize the hip joint and restore the normal hip center for bone development. The leg length discrepancies were corrected by an Ilizarov limb lengthening procedure at a later stage.

Arthritis, Infectious↗
PubMed1997

Randomized comparison of misoprostol and dinoprostone for preinduction cervical ripening and labor induction.

This study attempts to evaluate the clinical effects of prostaglandin (PG) E analogues in preinduction cervical ripening and labor induction and to compare the perinatal outcomes of these medications. Sixty women with term singleton pregnancies were randomized to receive dinoprostone vaginal tablets (group I) or misoprostol vaginal tablets (group II). The Bishop scores were evaluated before drug insertion and every 4 hours during induction. Clinical data and perinatal outcomes were also recorded. There were no significant differences in the preinduction conditions on mean initial Bishop scores between these two groups. Twelve hours after drug insertion, the mean Bishop scores were significantly better in group II (9.7 +/- 3.1 vs 7.3 +/- 2.5, p < 0.05). The mean time from insertion to delivery was shorter in group II (16.5 +/- 2.7 h vs 25.7 +/- 3.8 h, p < 0.001). There were no significant differences in spontaneous labor rate, need for oxytocin augmentation, type of delivery, and Doppler flow velocity waveforms of the umbilical artery. The average number of doses given per patient was 1.8 +/- 1.4 in group II vs 2.7 +/- 0.3 in group I (p < 0.05). The perinatal outcome was similar in the two groups. In conclusion, misoprostol not only appears to be a safe and effective agent for cervical ripening and labor induction but is also more efficient than dinoprostone.

Adult↗