Biomedical subjects

S H Chu

Publications and source records attributed to S H Chu.

At least 127 records · Page 7Linked to original sources

PubMed1996

Reconsideration of testicular biopsy and follicle-stimulating hormone measurement in the era of intracytoplasmic sperm injection for non-obstructive azoospermia?

To determine the possibility of finding motile spermatozoa and spermatids in patients with high serum follicle stimulating hormone (FSH) and spermatogenetic disorders proven by pathology, 100 cases of male infertility were reviewed. Of these, 71 patients were found to have non-obstructive azoospermia or severe primary spermatogenetic disorders, and 20 had obstructive azoospermia. A prospective study of the most recent 51 cases was conducted. Multiple testicular tissue biopsies were examined by a pathologist and a well-trained gynaecological technician. The findings of spermatozoa, spermatids and serum FSH concentrations were compared among six different histological groups. It was concluded that 51.2% of the non-obstructive azoospermic and failed spermatogenetic patients had spermatids and even motile 'shaking' spermatozoa and should be re-evaluated. In the non-obstructive azoospermic patients here, almost all the motile spermatozoa and spermatids were found in patients with a serum FSH concentration of < 30 mIU/ml. It is suggested that a testicular biopsy should be conducted in every case of non-obstructive azoospermia and spermatogenetic disorder, even in those patients with elevated serum FSH concentrations.

Biopsy↗

PubMed1996

Endothelin-1 concentrations and optimisation of arterial oxygenation and venous admixture by selective pulmonary artery infusion of prostaglandin E1 during thoracotomy.

In order to improve arterial oxygenation and venous admixture during one lung ventilation, the effect of selective infusion of prostaglandin E1 into the pulmonary artery of the ventilated lung was investigated in 12 adult patients undergoing thoracotomy. Patients' bronchi were intubated with a Mallinckrodt bronchial tube and ventilated with 66% oxygen in air. Cardiopulmonary factors such as systemic and pulmonary arterial pressures, pulmonary vascular resistance, blood gas analyses, cardiac output and airway pressure were measured before and during one-lung ventilation; venous admixture (Qs/Qt) was calculated. Serial blood samples were taken from the pulmonary artery of the ventilated lung for endothelin-1 estimation. One lung ventilation reduced the mean PaO2 from 42.1 (2.3) kPa to 11.8 (1.4) kPa (p < 0.001) and increased Qs/Qt from 10.8 (3.2)% to 39.2 (4.7)% (p < 0.001). Pulmonary vascular resistance also increased from 167 (24) dyne.s.cm-5 to 262 (38) dyne.s.cm-5 (p < 0.05) with a corresponding increase of plasma endothelin-1 (p < 0.05). After 30 min of one lung ventilation, PGE1 was infused continuously into the pulmonary artery of the ventilated lung at a rate which increased incrementally from 0.04-0.10 micrograms.kg-1.min-1. PaO2 increased to 20.7 (2.6) kPa (p < 0.01) and Qs/Qt decreased to 30.6 (3.5)% (p < 0.05). During the infusion, pulmonary vascular resistance reduced to 173 (30) dyne.s.cm-5 (p < 0.01). The plasma endothelin-1 concentration reached a plateau between the end of one lung ventilation (before closing the thorax) and 6 h postoperatively. This correlated inversely with the pre-operative forced expiratory volume in one second (r = -0.68, p < 0.005), declining to normal values 72 h after operation. The selective infusion of PGE1 into the pulmonary artery of the ventilated lung corrected pulmonary vasoconstriction and improved both arterial oxygenation and venous admixture during one lung ventilation for thoracotomy.

Aged↗

PubMed1996

Mechanical and electrophysiological effects of 8-oxoberberine (JKL1073A) on atrial tissue.

The effects of 8-oxoberberine (JKL1073A) on contractions and electrophysiological characteristics of atrial tissues were examined. In driven left atria of the rat JKL1073A (10-100 microM) increased twitch tension dose-dependently. In spontaneously beating right atria, JKL1073A increased twitch tension but decreased beating rate slightly. The positive inotropic and the negative chronotropic effect of 30 microM JKL1073A was not affected by prazosin (1 microM), propranolol (1 microM) and 3-isobutyl-1-methyl-xanthine (10 microM) but significantly suppressed by 4-aminopyridine (2 mM 4-AP). Current-clamp study revealed that JKL1073A prolonged rat atrial action potential duration (APD). This prolongation of APD by JKL1073A was decreased by pretreating the cells with 2 mM 4-AP. Voltage-clamp study showed that JKL1073A inhibited the integral of the transient outward current (I(to)) dose-dependently with a KD value of 3.66 +/- 0.93 microM in rat atrial myocytes. The equilibrium dissociation constant (Kd) for JKL1073A bindings to open state I(to) was 0.50 +/- 0.08 microM. The suppression of I(to) by 3 microM JKL1073A was accompanied by shortening of its inactivation time constant from 52.5 +/- 0.9 ms to 16.8 +/- 0.7 ms. V(0.5) for the steady-state inactivation curve of I(to) was shifted from -25.7 +/- 3.3 mV to -34.8 +/- 3.2 mV. In human atrial cells, similar inhibition of I(to) and prolongation of APD by JKL1073A was found. The KD value of JKL1073A for inhibition of the integral of I(to) in human atrial cells is 4.03 +/- 0.02 microM. The Kd for bindings to open state I(to) is 0.5 microM. Currents through K1 channels of rat and human atrial myocytes were not inhibited by JKL1073A at concentrations up to 10 microM. These results indicate that JKL1073A exerts a positive inotropic effect by inhibition of I(to). JKL1073A inhibit I(to) by binding to open state channels or shifting of the steady-state inactivation curve of I(to).

Animals↗

PubMed1996

Clinical use of omniflow vascular graft as arteriovenous bridging graft for hemodialysis.

From April 1992 to November 1995, 109 bridging arteriovenous fistulas were performed in 89 patients for hemodialysis at National Taiwan University Hospital. These included 61 Omniflow vascular grafts (OVG) in 47 patients and 48 GoreTex polytetrafluoroethylene (PTFE) grafts in 42 patients. There were 36 male and 53 female patients, whose ages ranged from 24 to 84 years with a mean of 59 +/- 2 years. The operation was performed under lidocaine local anesthesia with antibiotic prophylaxis. The anatomic configurations included 50 (45.9%) forearm loop grafts, 19 (17.4%) forearm straight grafts, and 40 (36.7%) thigh loop grafts. Hemodialysis via the bridging graft was started 2 weeks after the operation. The patients received hemodialysis 3 times a week or more when indicated. No patients suffered from limb loss. Pseudoaneurysm and graft infection requiring operation occurred 0.96% and 1.92% per patient year, respectively, in the OVG group, and pseudoaneurysm and graft infection both occurred 2.38% per patient in the PTFE group. In the OVG group, the thigh loop graft had better patency than the forearm straight graft. The forearm loop graft had a better patency rate than the forearm straight graft. In the OVG group, the 1 to 4 year patency rate was 77 +/- 6 % 58 +/- 8%, 48 +/- 9%, and 34 +/- 13%, respectively, whereas in the PTFE group, the 1 to 4 year patency rate was 69 +/- 7%, 50 +/- 9%, 43 +/- 10%, and 26 +/- 15%, respectively. Therefore, the Omniflow is a good alternative bridging graft for hemodialysis.

Adult↗

PubMed1996

Extracorporeal membrane oxygenation support for postcardiotomy cardiogenic shock.

Extracorporeal membrane oxygenation (ECMO) has had promising results in life-threatening respiratory failure and postcardiotomy cardiogenic failure. From October 1994 to October 1995, 18 patients received 19 ECMOs at National Taiwan University Hospital for severe cardiogenic shock after cardiac surgery. They included patients receiving cardiac massage or repeated bolus injections of norepinephrine to maintain blood pressure (n = 10), patients who could not be weaned off cardiopulmonary bypass after several attempts despite intraaortic balloon pumping and maximal doses of catecholamine (n = 7), and patients with progressive intractable cardiogenic shock after cardiac surgery. Venoarterial ECMO was set up via femoral artery (17 or 19 Fr cannula) and vein (19 or 21 Fr) in all patients except 2 infants. No left heart drainage was performed in any of the patients. The heparin-coated circuit (with Carmeda Bio-active Surface) was used in the last 13 patients to reduce bleeding. Ten (52.6%) of the 19 cases could be smoothly weaned off ECMO, and 6 (33.3%) of the 18 patients were discharged from the hospital in good condition. Four (80%) of the 5 patients after valvular surgery and all 3 heart transplant patients could be weaned off ECMO successfully with the survival rate being 60% and 67%, respectively. Complications included leg ischemia (n = 3), bleeding (n = 4), renal failure (n = 3), and tube rupture (n = 1). The inability to wean off ECMO was caused by multiple organ failure (n = 5), sepsis (n = 2), tube rupture (n = 1), and dysfunction of the ECMO system (n = 1). The major cause of multiple organ failure was hesitation to set up ECMO. Our preliminary results confirmed the effect of ECMO in postoperative cardiogenic shock.

Adult↗

PubMed1996

Clinical use of CarboMedics and St. Jude Medical valves.

Three hundred and twenty-six patients underwent CarboMedics valve implantation (CM) in the aortic (119 patients), mitral (148 patients) or aortic and mitral (59 patients) positions while 371 patients underwent St. Jude Medical valve implantation (SJ) in the aortic (113 patients), mitral (184 patient), or aortic and mitral (74 patients) positions at National Taiwan University Hospital from August 1991 through 1995. All patients received warfarin (Coumadin) anticoagulation with the target international normalized ratio around 1.5. The hospital mortality was 3.7% in the CM group and 4.3% in the SJ group. In the CM group at 5 years, the actuarial freedom from thromboembolism, valve thrombosis, and anticoagulant-related hemorrhage was 89.91 +/- 2.66%, 95. 23 +/- 1.50%, and 99.62 +/- 0.37%, respectively, and the actuarial survival rate was 90.4 +/- 1.6%. In the SJ group at 5 years, the actuarial freedom from thromboembolism, valve thrombosis, and anticoagulant-related hemorrhage was 94.79% +/- 1.70%, 98.80 +/- 0.72%, and 99.68 +/- 0.31%, respectively, and the actuarial survival rate was 91.3 +/- 1.7%. We therefore concluded that a similar survival rate was noted in the CM and SJ groups. With low dose anticoagulation, the complications of thromboembolism, valve thrombosis, and anticoagulant-related hemorrhage were low in the SJ group.

Adolescent↗

PubMed1996

The pulsatile impeller pump for left ventricular assist.

Because of severe hemolysis, especially on producing pulsatile flow by changing the rotating speed of the impellers, the traditional centrifugal pump was rarely used for long-term support of the failing heart. We therefore developed a motor driven pulsatile implantable impeller pump. The pulsatility was achieved by changing the rotating speed via introducing a square waveform voltage into the motor coil. The impeller vane was designed to have both radial and axial curves according to the stream surface and stream lines to reduce the thrombosis and hemolysis. Nine calves weighing 80 to 100 kg were used. With the calves under endotracheal general anesthesia, left posterolateral thoracotomy was performed to connect the inflow tube with the left atrial appendage and to anastomose the outflow tube with the descending aorta. The calves usually awoke and stood up within hours after discontinuation of anesthetics. Within 7 days, continuous monitoring of electrocardiogram, systemic and pulmonary arterial pressures, and central venous pressure were performed to adjust the pump flow to 40% to 50% of the cardiac output. During the survival of 4 to 54 days (mean 16.3 +/- 19.3 days with two calves surviving longer than 1 month), no significant deterioration of liver or renal function was noted. Because of bleeding, hemoglobin reduced from 11.4 +/- 1.8 to 9.0 +/- 1.3 g/dl, and the hematocrit decreased from 34.5 +/- 4.7 to 26.7 +/- 4.6%. No significant changes of free hemoglobin were noted. In our results, the device revealed competent pulsatile function without severe blood damage or organ dysfunction.

Animals↗

PubMed1996

Current status of heart assist and replacement in Taiwan.

The first clinical application of intraaortic balloon pumps (IABP) in Taiwan was in 1976 to treat post-cardiotomy cardiogenic shock. It is now the most commonly used circulatory assist. From 1991 to 1995, 186 patients received IABP support with an overall mortality rate 41.9%. The male patients had the best survival rate, 67%, after coronary artery bypass grafting. The first extracorporeal membrane oxygenation (ECMO) was in 1987 to treat intractable heart failure caused by severe acute rejection after heart transplantation. Because of poor outcome, patients only received ECMO sporadically during the past years. From November 1994 to November 1995, 30 patients received ECMO support with 50% of them eventually weaned from ECMO and 27% discharged. For short-term support or emergency rescue, ECMO was a good choice. When long-term support was required, the ventricular assist device (VAD) was a more suitable assist. One patient who received Thermedics VAD developed right heart failure and finally died of sepsis and multiple organ failure. VAD should be implanted before the secondary organ failure. The first successful clinical heart transplantation in Taiwan was performed on July 17, 1987. From 1991 to 1995, 102 patients underwent heart transplantation. The operative mortality was 3.9%, and the 1 and 5 year actuarial survival rates were 86 +/- 3% and 77 +/- 5%, respectively. To improve the success rate of clinical heart transplantation, organ donation should be encouraged.

Adult↗

PubMed1996