Biomedical subjects

C H Chiang

Publications and source records attributed to C H Chiang.

At least 55 records · Page 3Linked to original sources

PubMed1998

Effects of pH, electric current, and enzyme inhibitors on iontophoresis of delta sleep-inducing peptide.

Delta sleep-inducing peptide (DSIP), a peptide of nine amino acid residues, was used as a model drug to investigate the effects of pH, electric current, and enzyme inhibitors on the transdermal iontophoretic delivery of peptide drugs. DSIP was fairly stable in pH 4-9 buffer solutions but was cleaved by the skin enzymes during iontophoretic delivery. Enzyme inhibitors, such as o-phenanthroline, ethylene-diaminetetraacetic acid (EDTA), dilucine, and sodium deoxycholate, could inhibit the degradation of DSIP to a certain extent in the skin homogenate. Our results showed that metalloproteases were probably more important enzymes for DSIP hydrolysis. By using 0.2 mM o-phenanthroline in the iontophoretic delivery of DSIP at pH 4, we were able to significantly enhance the penetration of DSIP. The flux was about eight times as much as control (without o-phenanthroline) at pH 7.4.

Administration, Cutaneous↗

PubMed1998

Molecular characterization of Chinese G6PD deficiency by using polymerase chain reaction/single strand conformation polymorphism.

Using the polymerase chain reaction/single strand conformation polymorphism (PCR/SSCP), we studied the molecular characterization of 97 (86 male and 11 female) glucose-6-phosphate dehydrogenase (G6PD) deficient Chinese newborn babies and infants in southern Taiwan. Movement shifts were clearly seen in exon 2, 5, 6 and 12, respectively. No movement shift was seen in exon 9. Mutation confirmations were followed by direct sequencing. Using this approach we identified the molecular defect in 90 of the 97 above samples. Our results show a total of seven variants, the most common being at nucleotide (nt) 1376 mutation G-->T 42.3% (41/97) and at nt 1388 mutation G-->A 34.0% (33/97). The other mutation sites were at nucleotide 95 A--G (5.2%), nucleotide 392 G-->T (4.1%), nucleotide 493 A-->G (3.1%) and two new variants with mutation at nucleotide 371 A-->G (2.1%) and nucleotide 519 C-->G (2.1%). Still 7.2% (7/97) remained unidentified. There was no significant difference in G6PD activity among the different mutations. Simple and fast, PCR/SSCP may be suitable for molecular screening for G6PD deficiency in Chinese and other people.

Female↗

PubMed1998

Protective agents used as additives in University of Wisconsin solution to promote protection against ischaemia-reperfusion injury in rat lung.

1. An intervention to reduce ischaemia-reperfusion lung injury will be an important advance in transplant medicine. Although the mechanisms associated with producing ischaemia-reperfusion endothelial injury have not been completely elucidated, many of the injury mediators have been studied in detail. While no single pharmacological therapy is likely to be totally effective in eliminating this complex injury, we have developed a mixture of agents that are known to block pathways involved in producing ischaemia-reperfusion-associated lung vascular injury.2. The present study modified University of Wisconsin solution (UW) by adding one of the protective agents prostaglandin E1 (PGE1), dexamethasone (Dex) or dibutyryl cAMP (Bt2-cAMP), or a combination of these, to the perfusate of rat lungs exposed to 4 h of cold ischaemia followed by 1 h of reperfusion. Nine modified UW solutions were studied: (1) UW+Dex, (2) UW+PGE1, (3) UW+Bt2-cAMP, (4) UW+Dexx3, (5) UW+PGE1x3, (6) UW+Bt2-cAMPx3, (7) UW+Dex+PGE1, (8) UW+Dex+Bt2-cAMP, (9) UW+PGE1+Bt2-cAMP. These solutions were utilized in individual experiments to assess haemodynamic changes, lung weight gain, the capillary filtration coefficient (Kfc) and pathology in all lungs.3. The results indicate that lung weight gain and Kfc values were significantly lower than with UW alone in groups 1, 2 and 3, which contained only one additional protective agent. In groups 4, 5 and 6, which contain three times the concentration of each protective agent, both Kfc and lung weight gain were similar to those measured in groups 1, 2 and 3, i.e. lungs were protected but the protection was not dose dependent. In groups 7, 8 and 9, which contained two protective agents, lung weight gain and Kfc were greatly reduced compared with UW alone. Histopathological studies showed similar decreases in the injury profiles of lungs.4. Although UW contains several antioxidant protective agents such as allopurinol and glutathione, it did not provide effective protection in our ischaemia-reperfusion lung injury model. UW modified with an additive of PGE1, Dex or Bt2-cAMP attenuated ischaemia-reperfusion injury. Furthermore, UW containing two of these protective agents augmented the protection. Among the modified solutions, it appears that UW+PGE1+Bt2-cAMP protects the lungs to a greater extent than all other solutions used in our study. We suggest that preservation solutions containing PGE1-Bt2-cAMP will provide additional protective effects to organs stored for transplantation.

Adenosine↗

PubMed1998

Lymphoepithelial cyst of the parotid gland--a case report.

The lymphoepithelial cyst has been commonly termed branchial cleft cyst or branchial cyst. Although many theories, including the branchial apparatus theory, thymic duct theory, and inclusion theory, have been put forward, the etiology is still controversial. Parotid lymphoepithelial cysts are rare and could be divided into two groups, AIDS-related and non-AIDS related, by the relationship with HIV infection. A non-AIDS related lymphoepithelial cyst of left parotid gland in an 81-year-old man presenting as a parotid tumor is described. A left partial parotidectomy was carried out to remove the lesion. There was no recurrence after 2 years. Lymphoepithelial cysts of the parotid gland are often misdiagnosed as other benign tumors in spite of detailed preoperative investigations. Thus a pathological proof is needed for precise diagnosis. In addition, we also need to take the possibility of HIV infection into consideration, although Taiwan is not an AIDS epidemic area.

Acquired Immunodeficiency Syndrome↗

PubMed1998

Midtrimester maternal serum free beta-human chorionic gonadotropin levels: normal reference values for Taiwanese women.

BACKGROUND: The purpose of this study was to establish normative median values for maternal serum free beta-human chorionic gonadotropin (beta-hCG) during the second trimester of pregnant Taiwanese women. MATERIALS AND METHODS: We collected the data of midtrimester serum free beta-hCG concentration levels from 15,132 normal Taiwanese singleton pregnancies between 14 and 22 weeks' gestation. The maternal age on the day of delivery and maternal weight at the time of sampling were recorded in all cases. The relationship between gestational days and multiple of the median (MoM) levels of serum markers was analyzed using nonlinear regression methods. RESULTS: The median values of free beta-hCG in pregnant Taiwanese women were higher than those of pregnant white women. The log10 standard deviation distribution of free beta-hCG MoM values in the study population was 0.275 with a log10 mean of 0.0097. There were 1.81% of pregnancies with free beta-hCG levels less than 0.3 MoM and 11.33% with levels less than 0.5 MoM; 12.91% had serum levels greater than 2.0 MoM and 5.29% had serum levels greater than 3.0 MoM. CONCLUSION: Because of differences in race and methodology, any laboratory intended to provide determination of free beta-hCG for Down syndrome screening should establish its own normal reference values.

Adolescent↗

PubMed1997

The influence of endometriosis on the success of gamete intrafallopian transfer (GIFT).

PURPOSE: Our purpose was to evaluate the outcomes of gamete intrafallopian transfer (GIFT) therapy in patients with endometriosis. METHODS: One hundred eight GIFT cycles performed under the indication of endometriosis were compared to 156 GIFT cycles with indications of other disease entities. A maximum of seven oocytes was transferred into one or both fimbriate ends with prepared spermatozoa. Clinical pregnancy rates and outcomes were evaluated according to Mantel-Haenszel's chi-square test. Multiple logistic regression analysis was performed to determine factors influencing the success on pregnancy in the total treatment cycles. RESULTS: The anthropological variables, such as age of patients, duration of infertility, and semen grading, were comparable in both groups. The responses to controlled ovarian hyperstimulation (COH) were progressively decreased while increasing the severity of endometriosis conditions such as nonendometriosis, mild-form endometriosis, and advanced-form endometriosis patients. However, there were no significant differences in the clinical pregnancy rates (40.4, 36.7, and 41.7%, respectively), multiple pregnancy rates (34.9, 27.3, and 45.0%, respectively), and early pregnancy loss rates (27.0, 18.2, and 30.0%, respectively). Multivariate statistics of pregnancy rates that adjusted the effects of patients' age, tubal health, presence of active endometriosis and/or endometriomas, number of oocytes transferred, and quality of sperm exhibited no statistical significance between endometriosis and nonendometriosis groups. CONCLUSIONS: Our data show that patients with records of endometriosis have both a decreased ovarian response to gonadotropin stimulation and a decreased number of retrieved oocytes. Since the number of oocytes needed for the GIFT procedure is limited, pregnancy results for patients in the study group were comparable with those for patients in the control group.

Analysis of Variance↗

PubMed1997

Subconjunctival retention of C3F8 gas increased the success rates of trabeculectomy in young people.

In this study, the effect of subconjunctival retention of perfluoropropane (C3F8) gas on trabeculectomy was evaluated to determine if this maneuver would increase the success rate of the surgery. Thirty-two patients (under 35 years old) with a diagnosis of primary open-angle glaucoma or steroid-induced glaucoma were randomized into two groups to receive trabeculectomy: Group A (trabeculectomy alone, 16 eyes) and Group B (trabeculectomy with subconjunctival retention of 0.5 mL pure C3F8 gas, 16 eyes). The results showed that the typical appearance of a subconjunctivally retained C3F8 filtering bleb is highly distended in the first two weeks after surgery, followed by flattening and diffusing gradually. The average retention time of C3F8 gas within the subconjunctival space is 28 +/- 6 days. A higher success rate was noted in Group B than in Group A (94% versus 50%, p = 0.016) at a mean follow-up time of 12 months. However, there were no differences in complication rates and results of final visual acuity between the two groups (both groups had two patients lose more than two lines of vision, p = 1.0). Our study suggests that subconjunctival retention of C3F8 gas increases the success rate of trabeculectomy in young people in the intermediate-term (12 months) follow-up period.

Adult↗

PubMed1997

PGE1, dexamethasone, U-74389G, or Bt2-cAMP as an additive to promote protection by UW solution in I/R injury.

A method to reduce ischemia-reperfusion (I/R) injury can be an important criterion to improve the preservation solution. Although University of Wisconsin solution (UW) works as a lung preservation solution, its attenuation effect on I/R injury has not been investigated. We attempted to determine whether, by adding various protective agents, modified UW solutions will enhance the I/R attenuation by UW. We examined the I/R injury in an isolated rat lung model. Various solutions, e.g., physiological salt solution (PSS), UW, and modified UW solutions containing various protective agents such as prostaglandin E1, dexamethasone, U-74389G, or dibutyryl adenosine 3',5'-cyclic monophosphate were perfused individually to evaluate the I/R injury. Isolated rat lung experiments, with ischemia for 45 min, then reperfusion for 60 min, were conducted in a closed circulating system. Hemodynamic changes, lung weight gain (LWG), capillary filtration coefficient (Kfc), protein content of lavage fluid, concentration of cytokines, and lung histopathology were analyzed. Results showed that the acute I/R lung injury with immediate permeability pulmonary edema was associated with an increase in tumor necrosis factor-alpha (TNF-alpha) production. A significant correlation existed between TNF-alpha and Kfc (r = 0.8, P < 0.0001) and TNF-alpha and LWG (r = 0. 9, P < 0.0001), indicating that TNF-alpha is an important cytokine modulating early I/R injury. Significantly lower levels of Kfc, LWG, TNF-alpha, and protein concentration of lung lavage (P < 0.05) were found in the UW-perfused group than in the control group perfused with PSS. Modified UW promoted the protective effect of UW to further decrease Kfc, LWG, and TNF-alpha (P < 0.05). Histopathological observations also substantiated this evidence. In the UW+U-74389G group, bronchial alveolar lavage fluid contained lowest protein concentration. We conclude that the UW solution attenuates I/R injury of rat lung and that the modified UW solutions further enhance the effect of UW in reducing I/R injury. Among modified solutions, UW+U-74389G is the best. Further investigation of the improved effects of the modified UW solutions would be beneficial in lung transplantation.

Adenosine↗

PubMed1997

Interleukin-1 in ischemia-reperfusion acute lung injury.

Interleukin-1 (IL-1) is a proinflammatory cytokine produced by blood-borne and resident inflammatory lung tissue involved in the thrombotic occlusion of the pulmonary microcirculation and the increase of the vascular permeability following a wide variety of injuries and sepsis. The locally accentuated, organ-related activation of this cytokine seems to be responsible for the development of acute lung injury. The present study was conducted to determine if IL-1beta was produced in an ischemia-reperfusion (I/R) rat model subjected to lung injury. We measured sequential perfusate levels of IL-1beta by ELISA and we measured IL-1 gene expression in the rat lung tissue by a reverse-transcriptase polymerase chain reaction method. Little IL-1beta gene expression was observed in normal rat lung tissue. Perfusate IL-1beta slightly increased 2 h after induced ischemia and 3 h after reperfusion. IL-1beta gene expression rapidly increased as early as 30 min after ischemia and continued to increase for up to 120 min. IL-1beta gene expression was dramatically upregulated during reperfusion after cessation of ischemia, reached a peak at 1 h, and then gradually decreased (2 to 3 h) to near baseline levels. During ischemia, the increased IL-1 gene expression was not significantly different between the ventral and dorsal sites of the lung. However, IL-1 gene expression markedly increased on the dorsal part (the dependent site for a rat in a supine position) after reperfusion. From these results, it appears that IL-1 may have an important role in I/R lung injury.

Acute Disease↗

PubMed1997

Cardiac tamponade in Taiwan.

We retrospectively reviewed all of the patients who were treated for cardiac tamponade at Linkou Chang Gung Memorial Hospital between January 1991 and December 1995. There were a total of 112 patients (57 males, 55 females) with a mean age of 51 +/- 14 years (53 +/- 15, 49 +/- 13, respectively). Dyspnea was the most common complaint (85%). The mean blood pressure was 129 +/- 24/78 +/- 17 mmHg, and only 8% had a systolic blood pressure of less than 90 mmHg. Sinus tachycardia was the most frequent electrocardiographic finding (72%, 62/86). Diffuse low voltage was noted in 35% (30/86) of the patients and electrical alternans was seen in 17% (15/86). The mean volume of pericardial effusion was 610 +/- 263 ml. Sixty-five percent of the pericardial effusions were bloody, 31% were serosanguineous, 2% were purulent and 2% were chylous. Overall, 54.5% of the patients had malignant diseases. Of the 61 patients who died, 79% had malignancies. Thirty-five (57%) of these 48 patients had lung cancer. The mean survival time from emergent pericardiocentesis was 3.4 months. In conclusion, non-traumatic cardiac tamponade had a poor prognosis because most patients had malignant etiologies. There is still no definitive treatment for recurrent malignant pericardial effusion-induced cardiac tamponade. Percutaneous pericardiocentesis as clinically required may be the most appropriate treatment, since it is questionable whether such subjects should be subjected to the unnecessary pain and suffering associated with an operative procedure, considering their short mean survival time.

Adolescent↗

PubMed1997

Residual abnormalities of pulmonary function in asymptomatic young adult asthmatics with childhood-onset asthma.

We investigated the pulmonary function of male asthmatics with childhood-onset asthma. Our results revealed that adult asthmatics with mild symptoms apparently have abnormal pulmonary function. On the other hand, after a 3-6-month symptom-free period, and even after inhalation of bronchodilator, they still showed significant residual abnormalities in pulmonary function. Pulmonary function tests are very sensitive tools for the assessment of airway limitations during an acute asthmatic attack. However, these tests are not sensitive enough to detect residual abnormalities in asymptomatic asthmatics. Although the positive predictive rate for detecting small airway dysfunction in asymptomatic asthmatics is not high, FEF25-75 proved to be the best (63.2%) among the conventional pulmonary function parameters. We therefore suggest using FEF25-75 instead of FEV1 or peak flow rate in clinical practice for the conventional assessment of effectiveness of treatment, especially in the follow-up of asthmatic patients. More sensitive and simple tests are required in the future for detection of small airway dysfunction in asymptomatic asthmatics. Moreover, strict and early treatment of this abnormality with steroids is mandatory to prevent the formation of sequelae.

Adult↗

PubMed1997

Dibutyryl cAMP prevents increased vascular permeability caused by air embolism in isolated rat lungs.

BACKGROUND AND HYPOTHESIS: Venous gas bubbles are routinely detected in astronauts undergoing extravehicular activities at lower suit pressure. Venous air embolism increases the pulmonary arterial pressure and the vascular permeability leading to acute lung injury. In the present study we evaluated the protective effect of dibutyryl cAMP, aminophylline, and pentoxifylline on the pulmonary vasculatures after air embolism. METHOD: In isolated and perfused rat lungs, we induced air embolism by introducing air bubbles into the pulmonary artery. We measured the pulmonary arterial pressures and capillary pressure. Vascular permeability was determined by measuring the filtration coefficient (Kf) and the protein concentration in the lung lavage fluid. RESULTS: Air infusion caused pulmonary hypertension and increased vascular permeability, resulting in pulmonary edema. The Kf (in g.min-1.cm H2O-1.100 g-1) increased from 0.44 +/- 0.05 at baseline to 2.98 +/- 0.47 after air infusion. Pretreatment with DBcAMP prevented the increase in Kf (0.63 +/- 0.09) caused by air embolism without altering the hemodynamics. Aminophylline and pentoxifylline did not prevent lung injury induced by air embolism. Although aminophylline did not alter the response of pulmonary arterial pressure to air infusion, it elevated the capillary pressure to 5.1 +/- 0.4 mmHg, which was significantly greater than that in the lung receiving air infusion alone. CONCLUSION: Our results suggest that DBcAMP prevents the increase in vascular permeability caused air embolism. The ineffectiveness of aminophylline and pentoxifylline on the prevention of air embolism-induced lung injury remains for further investigation.

Aerospace Medicine↗

PubMed1996

Reduction in lymphocyte beta-adrenergic receptor density in infants and children with heart failure secondary to congenital heart disease.

To identify changes in catecholamine levels and beta-adrenergic receptor density in children with varying degrees of congestive heart failure, we measured plasma norepinephrine (NE), epinephrine, and beta-adrenergic receptor levels in 91 noncyanotic patients using high-performance liquid chromatography and a radioligand binding assay. Plasma NE levels in 41 patients with heart failure (694 +/- 236 pg/ml) were significantly higher than those in 50 patients without it (274 +/- 68 pg/ml, p < 0.001). In addition, beta-adrenergic receptor density was significantly lower in patients with heart failure (0.81 +/- 0.48 fmol/10(6) cells) than in those without it (2.43 +/- 1.09 fmol/10(6) cells, p < 0.001), but epinephrine levels were not significantly different between the 2 groups. The receptor reduction in heart failure correlated well with elevated plasma NE levels (r = -0.60, p < 0.001). The degree of left to right shunt flow and pulmonary systolic pressure correlated directly with plasma NE levels and inversely with beta-adrenergic receptor density. From the best compromise between sensitivity and specificity, the optimal cutoff point for heart failure was > 390 ng/ml for NE and < 1.30 fmol/10(6) cells for beta-adrenergic receptor density, respectively. A follow-up study in 15 of 30 patients with heart failure after surgery showed a significant decrease in plasma NE and an increase in beta-adrenergic receptor density. Changes in plasma NE levels and beta-adrenergic receptor density occur concurrently with clinical symptoms of heart failure and may be used as indexes for assessing the presence and severity of heart failure in infants and children.

Adolescent↗

PubMed1996

Pharmacokinetics and intraocular pressure lowering effect of timolol preparations in rabbit eyes.

Two timolol preparations, a gel and an eyedrop with a thickening agent, and one commercial eyedrop without a thickening agent, were studied in rabbits. After topical administration of these three preparations in rabbits, aqueous humor was withdrawn and the proteins removed from the samples by precipitation with acetonitrile. Timolol concentrations were determined directly by an HPLC method. The HPLC mobile phase was composed of methanol and 5 mM d-camphorsulfonic acid (in 1% acetic acid) with a ratio of 49:51 (v/v). A reversed phase C18 column was used to separate samples with a flow rate of 0.8 mL/min and a UV detector set at 284 nm. A two-compartment pharmacokinetic model was used to fit the aqueous humor level for determining the drainage (kd) and absorption rate constants (ka) in the precorneal area as well as the elimination rate constant (ke) of timolol in aqueous humor. For ka +kd, the eyedrop without a thickening agent had the highest value (0.160 min-1), followed by the eyedrop with a thickening agent (0.030 min-1), and the gel had the lowest value (0.009 min-1). It suggests that the gel has a longer retention time in eyes to improve ocular bioavailability and decrease side effects. The AUC0 approximately infinity for the aqueous humor profile with time coordinates were 4142, 2974, and 1604 micrograms min/mL, for the gel, the eyedrop with a thickening agent, and the eyedrop without a thickening agent, respectively. In another study, timolol preparations were also topically administered in alpha-chymotrypsin-induced glaucoma rabbits for determining the lowering effect on intraocular pressure (IOP). The durations of depressing IOP for the gel, the eyedrop with a thickening agent, and the eyedrop without a thickening agent were 24, 14 and 10 hrs, respectively. Thus, the gel preparation has a longer duration and a higher ocular bioavailability which might be further developed in the treatment of open-angle glaucoma.

Absorption↗

PubMed1996

Increase of ocular blood flow by some phytogenic compounds.

The effects of a number of phytogenic compounds on ocular blood flow were measured by the colored microsphere technique in rabbits. Methyltyramine and coumarin increased blood flow in all eye tissues tested. The blood flow of iris, ciliary body-iris root, retina and choroid was increased by methyltyramine for 255%, 322%, 189%, and 189%, respectively, and by coumarin for 375%, 193%, 139% and 299%, respectively, at 120 minutes after drug administration. Rescinnamine, apocynin and hesperetin also increased ocular blood flow in all eye tissues except retina. The blood flow of iris, ciliary body-iris root, and choroid was increased by rescinnamine for 344%, 234%, and 199%, respectively; by apocynin for 355%, 152%, and 414%, respectively; and by hesperetin for 265%, 136%, and 204%, respectively, at 120 minutes after drug instillation. These results indicate that these compounds could be used to treat ischemic eye diseases in the future.

Acetophenones↗

PubMed1996

Electrocardiographic findings in children with spinal muscular atrophy.

Most of the patients in this study with spinal muscular atrophy were found to have tremors of the isoelectric line in the electrocardiogram (ECG) tracings. There were a total of 47 cases of SMA (mean age 40.8 months). All three types of SMA had a similar incidence (about 80%) of tremors in the tracings (p = 0.885). In 7 cases the ECG tremors had an intermittent pattern. ECG tremors were commonly found in the majority of SMA patients and this finding, though non-specific, may suggest a possible SMA diagnosis.

Adolescent↗

PubMed1996

Nasal septal cyst--a case report.

The usual complications of submucous resection of the nasal septum (SMR) are septal hematoma, infection, hemorrhage, septal perforation, and nasal deformity. We present a case of nasal septal cyst which may be a rare complication of SMR. Entrapment of free nasal mucosal remnants or inward folding of incised septal mucosa is thought to be the cause. The patient underwent deroofment of the left cystic wall by lateral rhinotomy. There was no recurrence after one year.

Adult↗

PubMed1996

Mitochondrial NADH-coenzyme Q reductase deficiency in Leigh's disease.

A 4 1/2-month-old girl suffered from psychomotor retardation, generalized hypotonia, poor feeding, hyperreflexia, nystagmus, optical atrophy and choreoathetosis from the age of 3 months. Her blood lactate level was elevated to 40 mg/dL. Magnetic resonance imaging of her brain showed low T1 and high T2 signal intensities in the bilateral putamen, thalamus, red nuclei, substantia nigra, superior and inferior colliculi, cerebral peduncles and periaqueductal lesions. Muscle histochemistry and electron microscopic examinations were all normal except for variation in fiber size showing a myopathic change. An assay of muscle mitochondrial respiratory enzyme activities revealed a deficiency of NADH-coenzyme Q reductase. Molecular analysis did not reveal the putative T to G transversion at the nucleotide 8,993 of mitochondrial DNA in muscle biopsies. Leigh's disease was indicated by the clinical and radiologic manifestations. The patient died at 10 months of age from pneumonia and respiratory failure. There have been only sporadic reports of patients with Leigh's disease in Taiwan, and, to our knowledge, this is the first documented case of a Taiwanese patient with mitochondrial NADH-coenzyme Q reductase deficiency.

Base Sequence↗