Portal hemodynamics in living-related liver transplantation: quantitative measurement by Doppler ultrasound.
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Adult↗
Biomedical subjects
T Y Chen
Publications and source records attributed to T Y Chen.
Preoperative assessment of the portal vein in potential pediatric liver transplantation recipients: comparison of sonography and invasive portography.
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Adolescent↗
Outcome of medial segment in partial liver grafting.
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Adult↗
Extracellular zinc ion inhibits ClC-0 chloride channels by facilitating slow gating.
Extracellular Zn2+ was found to reversibly inhibit the ClC-0 Cl- channel. The apparent on and off rates of the inhibition were highly temperature sensitive, suggesting an effect of Zn2+ on the slow gating (or inactivation) of ClC-0. In the absence of Zn2+, the rate of the slow-gating relaxation increased with temperature, with a Q10 of approximately 37. Extracellular Zn2+ facilitated the slow-gating process at all temperatures, but the Q10 did not change. Further analysis of the rate constants of the slow-gating process indicates that the effect of Zn2+ is mostly on the forward rate (the rate of inactivation) rather than the backward rate (the rate of recovery from inactivation) of the slow gating. When ClC-0 is bound with Zn2+, the equilibrium constant of the slow-gating process is increased by approximately 30-fold, reflecting a 30-fold higher Zn2+ affinity in the inactivated channel than in the open-state channel. As examined through a wide range of membrane potentials, Zn2+ inhibits the opening of the slow gate with equal potency at all voltages, suggesting that a two-state model is inadequate to describe the slow-gating transition. Following a model originally proposed by Pusch and co-workers (Pusch, M., U. Ludewig, and T.J. Jentsch. 1997. J. Gen. Physiol. 109:105-116), the effect of Zn2+ on the activation curve of the slow gate can be well described by adding two constraints: (a) the dissociation constant for Zn2+ binding to the open channel is 30 microM, and (b) the difference in entropy between the open state and the transition state of the slow-gating process is increased by 27 J/ mol/ degreesK for the Zn2+-bound channel. These results together indicate that extracellular Zn2+ inhibits ClC-0 by facilitating the slow-gating process.
Animals↗
Subarachnoid fentanyl with diluted small-dose bupivacaine for cesarean section delivery.
BACKGROUND: The use of neuraxial opioid was very popular in recent years, and they may augment the analgesia produced by local anesthetic through direct binding with the spinal opioid receptors. Hemodynamic stability is very important during Cesarean section. Theoretically, the reduction of local anesthetic by addition of fentanyl would provide better hemodynamic stability and good anesthetic status. METHODS: Thirty healthy parturients undergoing Cesarean section were assessed in a randomized fashion. They were divided into two groups. Each subject received 5 mg hyperbaric bupivacaine plus 25 micrograms fentanyl (0.5 ml) and cerebrospinal fluid (CSF) 0.6 ml (Group M + F) or 8 mg hyperbaric bupivacaine plus 0.5 ml of CSF (Group M). The effects of hemodynamic stability, side effects, and complete analgesic duration were observed. RESULTS: It was disclosed that the hemodynamic status was more stable in group M + F. The incidence of nausea and vomiting appeared to be not statistically significant between groups. The incidence of pruritus was apparently higher in group M + F (93.5% vs. 0) but the incidence of shivering was much lower in group M + F (0 vs. 33.3%). The complete analgesic duration was longer in group M + F (146 +/- 47 min vs. 104 +/- 44 min). There were no significant differences in the anesthetic and surgical status, 1-min and 5-min Apgar scores, and the time of regression of sensory level to T10. CONCLUSIONS: The combination of small-dose bupivacaine with fentanyl could provide more stable hemodynamic status, longer postoperative analgesia, and lower incidence of shivering. The incidence of pruritus in group M + F was high, but it was usually mild.
Adult↗
Combination of bupivacaine scalp circuit infiltration with general anesthesia to control the hemodynamic response in craniotomy patients.
BACKGROUND: Sudden and overwhelming increases in blood pressure (BP) and heart rate (HR) during incision of the scalp may give rise to morbidity or mortality in patients with intracranial pathology undergoing neurosurgery. A modification of the method proposed by Labat to abate this circumstantiality was applied in a group of patients receiving craniotomy. The modified method was to combine scalp circuit infiltration of local anesthetic with general anesthesia to control the hemodynamic response to craniotomy. METHODS: Twenty-six patients scheduled to undergo craniotomy were randomly divided into two groups. Patients whose conditions or their current medication that might affect the stability of hemodynamics were excluded. In group A patients (N = 16) 25-30 ml of 0.25% bupivacaine was used for scalp circuit infiltration on the operation side, while in those of group B (N = 10) the same volume of 0.9% normal saline was used. After induction, anesthesia was maintained with 0.6% to 1.2% end-tidal isoflurane (ET-Iso) and 50% N2O in oxygen (N2O:O2 = 2 l/min:2 l/min). The end-tidal CO2 was kept within the range of 25-30 mmHg. BP and HR were recorded every five min before incision and then every two min after incision until one hour after induction. ET-Iso was also recorded every two min throughout a period of sixty min. If the BP and HR increased above 20% of the baseline (10 min before incision), thiopental 2.5 mg/kg and fentanyl 2 micrograms/kg were administered. If hypertension became sustained, the isoflurane concentration was adjusted until an acceptable level was obtained. RESULTS: The mean BP during the surgery was 92 +/- 1 mmHg in group A and 92 +/- 7 mmHg in group B. The difference in BP between incision to 6 min after incision was statistically significant (P < 0.05). The mean HR during surgery was 101 +/- 5 beats/min in group B and 91 +/- 2 beats/min in group A, the difference of which was not statistically significant. All of the patients in group B required a deepened anesthesia to keep the BP and HR within the normal range, but no patient in group A had such need. The average concentration of ET-Iso during the 60 min period was 0.95 +/- 0.12% in group B and 0.41 +/- 0.01% in group A, respectively. The difference was statistically significant (P < 0.05). CONCLUSIONS: Our results showed that scalp circuit infiltration with 0.25% bupivacaine significantly improved the cardiovascular stability and reduced the requirement of isoflurane during craniotomy. The routine use of bupivacaine scalp circuit infiltration in patients undergoing craniotomy should be considered.
Adult↗
Intraoperative Doppler ultrasound in liver transplantation.
The purpose of this study was to determine the utility of intraoperative Doppler ultrasound for the diagnosis and reduction of the vascular complications in liver transplantation. This study included 19 pediatric and 5 adult patients. In the pediatric group, 12 patients received living related liver transplantation (LRLT), two splitting liver transplantation (SLT), three reduced-size liver transplantation (RLT) and two full-size pediatric liver transplants (FPLT). The hemodynamics and waveform of the hepatic vein, portal vein and hepatic artery were evaluated by intraoperative Doppler ultrasound (US) after reperfusion of the graft. Unsatisfactory hemodynamics was identified in nine cases, including decrease hepatic venous flow (6-9 cm/s) with non-pulsative flat waveform (adults, n = 2 and LRLT, n = 2); portal vein thrombosis (LRLT, n = 1); decrease portal flow (8 mL/min/kg) (LRLT, n = 1); occlusion of the portal vein (SLT, n = 1); poor arterial flow with dampened artery waveform (FPLT, n = 2). These abnormalities were all successfully re-reconstructed by surgical procedures and achieved a graft survival rate of 100%. Two late vascular complications including hepatic venous thrombosis and recurrent portal vein stenosis with splenorenal shunt were discovered 1 month later. They were treated effectively by surgical thrombolectomy and percutaneous balloon dilatation and metallic coils embolization respectively. Three patients died of non-vascular complications and all patients who underwent LRLT survived with a resultant 87.5% overall survival rate. In conclusion, intraoperative Doppler US is efficient in detecting abnormal hepatic hemodynamics, which permits early intervention and hence a better prognosis for the patients. Re-reconstructive procedures were monitored closely under Doppler US guidance until proper flow and wave-form were established. This reduces post-transplant vascular complications and thereby eliminates the likelihood of a lethal complication that might call for re-transplantation.
Adolescent↗
Post-transplant changes of segment 4 after living related liver transplantation.
The purpose of this study was to evaluate the outcome of the medial segment of the graft after living related liver transplantation (LRLT). Of the 12 pediatric recipients who underwent LRLT, 2 received whole left liver graft, 1 left lateral segment graft, and 9 extended left lateral segment grafts. The hepatic veins of the donor were reviewed and the volume of the medial segment and left lateral liver was measured before and 6 months after liver transplantation. The flow velocity and direction of the portal vein in the medial segment graft was also evaluated by Doppler ultrasound. The grafted livers of all recipients showed a substantial increase in volume of 9-120% 6 months after LRLT. For the left lateral segment, an increase in volume was found in all cases ranging from 21 to 245%. For the medial segment, volume increases of 5-48% were found in seven cases with normal hepatopetal flow detected inside the segment 4 intrahepatic portal vein. In four cases, the partial medial segment graft of the extended left lateral liver graft decreased in volume from 33 to 69%. Among these four cases, slow flow (n = 2) and hepatofugal flow (n = 1) were also detected in the intrahepatic portal vein of the medial segment. Mapping of the tributary of the hepatic veins of the graft revealed inadequate venous drainage of the partial segment 4 graft, which may be considered as the cause of the atrophic change of the partial segment 4 graft. In conclusion, different regenerative rates between the left lateral segment and the medial segment were noted, with a greater rate in the left lateral segment. The venous drainage of the medial segment is of primary concern in the determination of the outcome of the regeneration. Atrophic change occurs when inadequate hepatic venous drainage is encountered. Therefore, if an extended left lateral liver graft is required, the corresponding draining veins of the partial medial segment must be preserved. Otherwise, whole left liver or left lateral segment graft would be a better choice.
Blood Flow Velocity↗
NitroG-L-arginine methyl ester decreases minimum alveolar concentration of isoflurane and reduces brain nitric oxide synthase activity in rats.
BACKGROUND: Nitric Oxide (NO), an endogenous messenger produced by the enzyme nitric oxide synthase (NOS), is recently introduced to be involved in inhalational anesthesia. We have previously reported that a specific NOS inhibitor, nitroG-L-arginine methyl ester (L-NAME), reduces the value of minimum alveolar concentration (MAC) for isoflurane anesthesia in rabbits. The purpose of this study is to evaluate the effects of the NOS inhibitor, L-NAME, on isoflurane MAC and NOS activity in rats. METHODS: Adult Wistar rats receiving isoflurane inhalation were randomly divided into two groups, with eight rats in each group. In the study group, L-NAME 30 mg/kg was given 60 min before the inhalation of isoflurane. Normal saline was given to the control group instead. The data of MAC, blood pressure (BP), and heart rate (HR) were recorded. The vital signs, such as EtCO2, PaO2, and temperature, were maintained within normal ranges. The activity of NOS in cerebellum was assessed by measuring the conversion of L-[3H] arginine to L-[3H] citrulline. All data were presented as mean +/- SD. Statistical analysis was performed using Student's t-test, where P < 0.05 was considered significant. RESULTS: In the presence of L-NAME (30 mg/kg), the MAC for isoflurane was markedly reduced from 1.6 +/- 0.20% (study group) to 1.0 +/- 0.09% (control group) (P < 0.05). The activity of cNOS in cerebellum was 220.09 +/- 23.64 (pmol/mg protein/30 min) in the control group, and in contrast a sharp reduction as low as to 115.40 +/- 24.85 (pmol/mg protein/30 min) was seen in the study group. CONCLUSIONS: The involvement of NO in the mechanism of isoflurane anesthesia can be demonstrated by the fact that the NOS inhibitor, L-NAME reduces the level of MAC and the cerebral NOS activity in rats.
Anesthetics, Inhalation↗
Attenuation of the catecholamine responses by electroacupuncture on Jen-Chung point during postoperative recovery period in humans.
In this study, Jen-Chung (J-C) point was stimulated by electroacupuncture (EA) in 10 patients, and by placebo treatment in 10 controls, immediately after termination of inhalation for 15 min. During the postoperative recovery period, plasma catecholamine (CA) levels were assessed before (0) and 15 and 30 min after treatment. The time from cessation of inhalation to the first eye opening and to extubation did not differ between groups. The plasma catecholamine levels increased by 30% from 0 to 15 min in the control group but decreased by 6% in the EA group. The levels at 30 min were approximately the same as at time 0. The change in catecholamine levels from 0 to 15 min was significantly lower (P < 0.02) in the EA groups than the control group.
Acupuncture Points↗
Retrodental fibrocartilaginous mass. Report of a case.
STUDY DESIGN: This is a report of a 63-year-old woman with a retrodental fibrocartilaginous mass and myelopathy. OBJECTIVE: To describe the pathophysiology of the retrodental fibrocartilaginous mass formation and its association with the C2-C3 disc. SUMMARY OF BACKGROUND DATA: High cervical disc protrusion is an uncommon condition and presents even more rarely as a craniovertebral junction mass with spinal cord compression. Uncertainty remains regarding the etiology of its formation in the retrodental region. METHODS: The patient underwent surgical intervention with transoral decompression and posterior C1-C2 skeletal fusion with bony graft. RESULTS: On the basis of dynamic plain radiographs, magnetic resonance imaging, and surgical pathology, the origin of the mass may have been the C2-C3 disc. CONCLUSIONS: We hypothesized that the mechanism underlying the posterior odontoid fibrocartilaginous mass with spinal cord involvement most likely originate upward migration of the C2-C3 annulus fragment to the atlantoaxial joint as a result of aging. Secondary fibrocartilaginous metaplasia plays a major role in creating such disc-like material. To prevent unrecoverable myelopathy, early detection and anterior decompression with posterior C1-C2 skeletal fixation and bony fusion are the best treatment methods.
Bone Transplantation↗
Variations of the middle and inferior right hepatic vein: application in hepatectomy.
We evaluated the anatomic variations of the middle right hepatic vein (MRHV) and inferior right hepatic vein (IRHV) and their clinical application to the possibility of right subtotal hepatectomy. In 400 of normal livers studied with ultrasound, the IRHV was found to drain segment 6 of the liver and flow into the inferior vena cava (IVC) in 72 (18%) cases. In 22 (5.5%) cases, the MRHV was found to drain segment 5 of the liver and flow into the IVC. The size of the IRHV ranged from 0.1 cm to 0.8 cm with an average of 0.46 cm. For the MRHV, the sizes ranged from 0.1 cm to 0.9 cm with an average of 0.34 cm. In 10/79 (12.6%) cases the IRHV and in 4/ 22 (18.1%) cases the MRHV were bigger than the right hepatic vein (RHV). The distance between the RHV and IRHV ranged from 3 cm to 5 cm with an average of 3.7 cm. The distance between the RHV and MRHV ranged from 3 cm to 3.3 cm with an average of 3.1 cm. A hyperechoic edge, similar to that of the portal vein, was observed at the wall of the hypertrophic IRHV and was 0.3 cm or larger in size. Preoperative delineation of this complex venous anatomy is very important. It provides vital information in the preoperative evaluation needed before performing a right subtotal hepatectomy with preservation of segment 6 or segment 5 of the liver, and with RHV resection. Prior to undertaking a right hepatectomy, clamping the hypertrophic MRHV and IRHV electively may minimize intra-operative blood loss and extrahepatic spread of the malignancy.
Adolescent↗
Efficacy of surgical treatment in traumatic central cord syndrome.
BACKGROUND: Controversy surrounds the treatment of traumatic central cord syndrome (TCCS), as there are strong advocates for nonsurgical treatment for most patients. However, conservative treatment has been shown to yield a longer period of discomfort from pain and weakness in certain cases. METHODS: In a retrospective review of 114 patients presenting with acute or chronic TCCS from 1988-94, four different age groups were separately observed under different treatments. Motor and sensory recovery were assessed. RESULTS: Better results were achieved in younger patients, with or without radiographic abnormalities, and in patients with clinically correlated encroaching cord lesions who received early surgical decompression. CONCLUSIONS: Surgical intervention for TCCS must be addressed with careful clinical and radiographic survey. Removal of offending lesions in the subacute period results in significant motor and sensory improvement in short-term and long-term follow-up.
Acute Disease↗
Early seizures after severe closed head injury.
BACKGROUND: We studied the incidence and clinical significance of early post-traumatic seizures after severe closed head injury. METHODS: This prospective study is based on clinical observation of 3340 adult patients with severe closed head injuries, each of them having a Glasgow Coma Scale (GCS) 3 to 8 after trauma. Anticonvulsant agents were not given to these patients unless there was evidence of seizure. RESULTS: One hundred and twenty-one patients (3.6%) experienced seizures within 1 week after head injury; 42 of these (1.26% of the series) had seizures within 24 hours after trauma. The incidence of intracerebral parenchymal damage was found to be higher among those patients who developed seizures in the first week (66.1%) than in those who did not (62.7%). However this result did not reach statistical significance. The patients with early seizures had a lower mortality rate (p < 0.01). In patients who survived from the initial injury, the occurrence of early post-traumatic seizures did not appear to influence the neurological recovery at 6 months after injury. CONCLUSION: Presence of intracerebral parenchymal damage on CT scan after severe closed head injury does not increase the risk of early post-traumatic seizures. With proper treatment, patients presenting with early seizures may have a lower mortality rate. However, the occurrence of early seizures does not influence the neurological recovery in patients who survive the initial severe closed head injury.
Adolescent↗
Nerve regeneration after terminolateral neurorrhaphy: experimental study in rats.
Four methods of nerve terminolateral neurorrhaphy (TLN) were studied in rat experimental model. In Group A, the distal end of a severed peroneal nerve was sutured end-to-side with an intact tibial nerve trunk, without removal of the tibial epineurium at the suture site. In Group B, the distal end of a severed peroneal nerve was sutured end-to-side with the intact tibial nerve trunk, with removal of the tibial epineurium at the suture site. In Group C, a nerve segment was bridged between the distal part of the severed peroneal nerve and the intact tibial nerve with two end-to-side sutures. In Group D, the proximal end of a severed tibial nerve was sutured end-to-side with the peroneal nerve trunk. Through electrophysiologic, histologic, and ultrastructural examinations, the following conclusions were drawn: 1. Nerve regeneration is possible after TLN. 2. The regenerating fibers after TLN have the ability to penetrate the endoneurium, perineurium, and epineurium. 3. After different methods of TLN, the regenerating fibers grow in both a flowing-out and a filling-in fashion.
Anastomosis, Surgical↗
Non-AIDS-related primary intraosseous Kaposi's sarcoma: case report and literature review.
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Acquired Immunodeficiency Syndrome↗
Stress appraisal and social support of Chinese mothers of adult children with mental retardation.
Thirty Chinese mothers of adult children with moderate to severe mental retardation were interviewed to explore the source and nature of their stress and social support. Results revealed child-related and parent-related stress specific to these mothers. The most common stressors were future planning and behavioral problems of the target offspring. Mothers received tangible, emotional, and informational support mainly from family members and training center staff. Some evidence was also found for the optimal-matching model of stress appraisal and social support. Regardless of the duration of stress, all forms of support were perceived as equally useful for uncontrollable stress, whereas tangible support was regarded as more useful than informational support for controllable stress.
Adult↗
NitroG-L-arginine methyl ester reduces the minimal alveolar concentration of isoflurane in rabbits.
BACKGROUND: Recently, some studies suggested that nitric oxide (NO) plays a role as a mediator in the central nociceptive pathways and is possibly involved the mechanisms of anesthesia and wakefulness. Inhibition of the L-arginine-NO pathway in the central nervous system may result in an anesthetic, analgesic, or sedative effect. The aim of the present study was to evaluate the effects of the nitric oxide synthase inhibitor (NOSI), nitroG-L-arginine methyl ester (L-NAME), on the threshold for isoflurane anesthesia in rabbits. METHODS: Sixteen New Zealand rabbits were randomly divided into two groups, with eight rabbits in each group. In the study group, a dose of L-NAME 30 mg/kg was injected i.v. daily as pretreatment on three consecutive days, and the fourth dose of L-NAME was given 30 min before the study began. Normal saline was given to the control group. Data of minimal alveolar concentration (MAC), blood pressure (BP), and heart rate (HR) were collected from both groups. Vital signs, such as EtCO2, O2 saturation, and temperature, were maintained within the normal range. All data were described as mean +/- SEM. Statistical analysis was performed using Student's t-test, where p < 0.05 was considered significant. RESULTS: MAC of isoflurane in the control group was 1.90 +/- 0.12%. MAC of the L-NAME group was 1.70 +/- 0.22%, significantly lower than the control group (p < 0.05). CONCLUSIONS: Our preliminary result shows that the MAC of isoflurane in animals treated with L-NAME was lower than that in the control group. It is suggested that inhibition of the nitric oxide pathway may enhance the effect of isoflurane.
Anesthetics, Inhalation↗