Loudness discomfort levels in patients with conductive and mixed hearing loss

OBJECTIVE

The purpose of this study is to investigate the effects of conductive component on the loudness discomfort level (LDL) judgments. The relation between LDL value and the magnitude of air-bone gap in such subjects was also assessed.

METHODS

LDLs were obtained from 100 ears of 50 hearing-impaired subjects. Twenty five subjects (50 ears) had either conductive or mixed hearing loss for both ears. Another 25 subjects (50 ears) with bilateral sensorineural hearing loss served as control. LDL measurements were performed using the method reported by Hawkins et al. in 1987. LDL data were plotted and analyzed as a function of hearing loss for three stimulus frequencies (0.5, 1.0 and 2 kHz). Also, LDL values were plotted as a function of air-bone gap in the conductive group.

RESULTS

LDLs were significantly higher in subjects with conductive or mixed hearing loss for all three tested frequencies. There is a significant positive correlation between LDL value and the magnitude of air-bone gap for all three test frequencies. Considerable intersubject variability was found in LDLs obtained from subjects with conductive component which prevented the accurate prediction of LDLs from threshold data for such patients.

CONCLUSION

The large intersubject variation in LDL data strongly suggests the need for individualized LDL measurements in patients with conductive or mixed hearing loss. Higher LDLs indicates that higher maximal power output can be prescribed for such patients without worrying about loudness intolerance.

HeartMate left ventricular assist device for long-term circulatory support

We describe three successful cases of HeartMate left ventricular assist device (LVAD; Thermo Cardiosystems, Woburn, MA, USA) implantation in patients with end-stage heart failure for long-term circulatory support. Patient 1 was a 34-year-old woman with postpartum cardiomyopathy. Patients 2 and 3 were both males with dilated cardiomyopathy, 50 years and 21 years of age, respectively. They all presented in cardiogenic shock with decreased sensorium and anuria. Temporary mechanical support with an intra-aortic balloon pump or extracorporeal membrane oxygenation (ECMO) was needed for life support. Because bleeding and right ventricular failure often occur after HeartMate LVAD implantation, we used a Vascutek tube (Vascutek Ltd, Inchinnan, Scotland) graft to wrap inflow and outflow valve conduits and ECMO as a bridge to HeartMate LVAD implantation. Following surgery, cardiac output increased from 2.70, 2.06 and 2.53 L/min to 4.50, 5.80 and 5.00 L/min in the three patients. HeartMate LVAD can provide safe and stable long-term circulatory support without the need for anticoagulation. One of the patients remained on HeartMate for 287 days before undergoing successful heart transplantation. Patients with HeartMate LVAD are ambulatory and may be discharged while awaiting heart transplantation. Heart function may recover after long-term ventricular unloading with HeartMate LVAD.

Use of extracorporeal membrane oxygenation to rescue a child with acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) carries a high mortality of about 60%. The results of conventional treatments for ARDS are poor. We report the use of extracorporeal membrane oxygenation (ECMO) to rescue a child with ARDS. The patient, a 7-year-old boy, underwent a Ross procedure and mitral valvuloplasty because of severe aortic and mild mitral regurgitation. ARDS due to massive transfusion and prolonged cardiopulmonary bypass developed in the early postoperative period. Hypoxemia persisted despite conventional treatments, including pressure-controlled ventilation and high-frequency ventilation. Finally, venovenous ECMO was used to rescue the patient. With ECMO support, gas exchange was well maintained with a lower ventilator setting, and ventilator-induced lung injuries were avoided. ECMO was used for 183 hours, at which point the boy was weaned without complications. His recovery was uneventful. At the latest follow-up, 6 months after the operation, he was in New York Heart Association function class I and had no complaints of lung disease. This case suggests that venovenous ECMO can be a rescue method for patients with ARDS that is refractory to conventional treatments.

Partial left ventriculectomy as a biologic bridge to heart transplantation

Heart failure refractory to medical treatment is consuming an increasingly large proportion of health care resources. Partial left ventriculectomy has recently been used to treat patients with end-stage dilated cardiomyopathy. A 45-year-old man in end-stage heart failure had progressive exertional dyspnea for 3 years. Cardiac catheterization showed dilated cardiomyopathy with severe pulmonary hypertension and severely impaired left ventricular function. After partial left ventriculectomy, cardiac output increased from 2.11 L/min to 5.0 L/min. The left ventricular ejection fraction measured by radionuclide angiography increased from 13% preoperatively to 28% 1 month after the operation. The patient was discharged and monitored at the outpatient clinic. He had an exercise capacity of NYHA functional class II. However, he received heart transplantation 10 months after the partial left ventriculectomy because of recurrent heart failure. Partial left ventriculectomy improves heart function and may be used as a bridge to heart transplantation as an alternative to ventricular assist devices.

Insertion of percutaneous ECMO cannula

Extracorporeal membrane oxygenation plays a very important role in resuscitation when patients are approaching impending death, because it can provide adequate cardiac and pulmonary support immediately. But percutaneous tunnel creation is a critical step for set-up of extracorporeal membrane oxygenation by percutaneous Seldinger technique. A guidewire dilator forceps used in percutaneous tracheostomy was tried to create the femoral subcutaneous tunnel. We found it could make easy the advancement of the percutaneous cannula into the vessels and over-dilatation of the vessels could also be prevented by controlled jaw opening.

Combined heart transplantation and resection of dissecting aneurysm of ascending aorta and aortic arch: a case report

A 21-year-old male patient had suffered from palpitation and exertional dyspnea since October, 1997. He was admitted to our hospital, and a series of examinations were performed. Chest computed tomography (CT) revealed marked dilatation of the ascending aorta (about 7.5 cm at the proximal portion) and aortic annulus, an intimal flap in the ascending aorta and aortic arch was also noted. Cardiac catheterization revealed the pulmonary capillary wedge pressure was 33 mmHg, pulmonary artery pressure was 47/38 mmHg with a mean of 35.4. The cardiac index was 1.01 l/min/m2. Poor left ventricular contractility was shown by a left ventricular ejection fraction (LVEF) of 13.8% and a right ventricular ejection fraction (RVEF) of 5.13% by a radionuclide angiogram (RNA) study. Under the diagnosis of dilated cardiomyopathy and dissecting aortic aneurysm of the ascending aorta and aortic arch, he was put on a waiting list for heart transplantation. On November 11, 1997 he received heart transplantation. Resection of the dissecting aneurysm of the ascending aorta and the aortic arch and replacement with a 26 mm Vascutek graft were performed first under deep hypothermia and retrograde cerebral perfusion. Then while he was rewarming up, heart implantation was performed. He was discharged 30 days after surgery and has been doing well since then. As far as we know, no literature regarding combined heart transplantation and resection of a dissecting aneurysm of the ascending aorta and aortic arch has been reported.

[Relation between myocardial cAMP and renin-angiotensin system activation after acute pressure overload]

In order to investigate the relationship between cAMP and myocardial renin-angiotensin system activation after acute pressure overload, an animal model of acute pressure overload was established by constriction of abdominal aorta. It was found that angiotensin converting enzyme (ACE) mRNA and protein expression were increased markedly, ACE activity and angiotensin II content were also elevated significantly in rat heart 1 h after acute pressure overload, and the increases were kept at high level. Meanwhile the myocardial cAMP concentration was increased significantly at 0.5 h, reached the peak at day 5, and returned to normal at day 30 after operation. Then cardiomyocytes were cultured to observe whether ACE gene expression can be induced by cAMP. The results showed that elevation of cAMP content in cultured cardiomyocytes stimulated by isoproterenol (ISO, 0.01 micromol/L) increased ACE mRNA and protein expression, and also increased ACE activity and Ang II content in cultural medium. These results suggest that cAMP plays a role in the mechanism of activation of myocardial renin-angiotensin system induced by pressure overload.

Rescue for acute myocarditis with shock by extracorporeal membrane oxygenation

BACKGROUND

Acute myocarditis (AM) complicated with refractory cardiogenic shock carries a very high mortality. We report our experience in treating these patients, who were rescued by extracorporeal membrane oxygenation (ECMO) and intravenous immunoglobulin.

METHODS

Over a 5-year period, 5 patients with AM were rescued with ECMO in our hospital. Femoral venoarterial ECMO was performed in 4 patients, and right atrium-left atrium-aorta ECMO in the other 1 due to ventricular dysfunction. Hemofiltration was applied to 3 patients. Marked elevated creatine kinase, its MB form, and troponin T (TnT) were found before ECMO.

RESULTS

All the patients could be weaned off the ECMO after 140.0+/-57.7 hours of ECMO support. One patient died of multiple organ failure 10 days later after removal of ECMO, resulting in a 20% mortality. Renal function returned to normal in all survivors. The 4 survivors were discharged uneventfully in 23.3+/-8.3 days and resumed functional class I status. The TnT level declined to the low level within 3 days (slope -4.94+/-1.18 ng/mL/day), and might be an indicator of good recovery of myocardium.

CONCLUSIONS

ECMO can provide an effective and simple treatment for critical AM with a satisfactory result and reduce the possibility of progressive cardiomyopathy.

Outcomes of transcatheter valvotomy in patients with pulmonary atresia and intact ventricular septum

The results of transcatheter valvotomy in pulmonary atresia with intact ventricular septum (PA-IVS) patients are presented with an attempt to identify the predictive factors for pulmonary valvotomy alone as definitive treatment. Between June 1995 and December 1997, 14 PA-IVS neonates with tripartite right ventricle underwent an attempted pulmonary valvotomy. For perforation of the pulmonary valve, a guidewire was used in 4, and a radiofrequency guidewire in 10 patients. Two outcome groups were identified. Group I included those in whom transcatheter treatment achieved a definitive success; group II patients required surgery despite an initial successful valvotomy. The attempt failed in 3 patients, 1 of whom had pericardial effusion. Perforation of the pulmonary valve was achieved in 11 patients: 2 with a guidewire and 9 with a radiofrequency guidewire. A subsequent balloon valvuloplasty was performed in these 11 patients. After valvuloplasty, mean right ventricular pressure decreased from 124 +/- 24 to 60 +/- 15 mm Hg (p <0.01). One died of heart failure and infection 10 days later, despite successful weaning from prostaglandin E1. Group I patients (n = 6) were treated with transcatheter valvotomy alone. Group II patients (n = 4) required right ventricular outflow patch. Significant differences between the 2 groups (group I vs II) were identified in tricuspid valve Z value (0.52 +/- 0.37 vs -1.25 +/- 0.48, p <0.05), pulmonary valve Z value (-3.47 +/- 0.59 vs -5.43 +/- 0.94, p <0.05), and ratio of right-to-left ventricular area on the apical 4-chamber view (0.73 +/- 0.06 vs 0.49 +/- 0.03, p <0.05). There were no significant differences in hemodynamic characteristics between the 2 groups. After a follow-up period ranging from 7 to 35 months (mean 18 +/- 10.3), the most recent echocardiograms in the 10 patients showed a mean pressure gradient across the pulmonary valve of 17 +/- 15 mm Hg. All 10 patients had an oxygen saturation of >92%. Transcatheter valvotomy using a radiofrequency guidewire is a safe and effective treatment in selected patients with PA-IVS. Transcatheter valvotomy can be a definitive treatment in PA-IVS patients with a tricuspid valve Z value > or = -0.1, pulmonary valve Z value > or = -4.1 and ratio of right-to-left ventricular area > or = 0.65.

Heart transplantation with marginal recipients and donors

With improvements in surgical techniques and management of postoperative complications, heart transplantation can now be performed with donors and recipients who were previously considered unsuitable. In this study, we report the results of heart transplantation with marginal donors and recipients in our hospital. From June 1993 through June 1998, we performed 79 heart transplantations. Marginal recipients were defined as those with high pulmonary vascular resistance (> 6 Wood units), severe renal impairment (serum creatinine > 2 mg/dL and creatinine clearance < 50 mL/min), or severe hepatic dysfunction (ALT and AST > 100 IU/L or serum bilirubin > 2.5 mg/dL). Marginal donors were those with any of the following conditions: old age (> 40 years), size mismatch (donor/recipient body weight ratio < 0.8), history of chronic alcohol use, previous cardiopulmonary resuscitation and hypotension, hepatitis B or C virus positivity, coronary artery disease, high-dose dopamine (> 10 micrograms.kg-1.min-1), or prolonged allograft ischemic time (> 4 hours). Of the 79 transplantations performed, 45 (58%) involved marginal recipients or donors. The 30-day mortality rate was 5%, and the 1-year and 5-year survival rates were 87% and 83%, respectively. The survival rates did not differ significantly between cases involving marginal donors or recipients and those involving nonmarginal donors and recipients. There were 27 marginal recipients (34%), only one of whom died during surgery. Five of six recipients with severe renal impairment needed short-term hemodialysis after transplantation. Recipients with high pulmonary vascular resistance had a higher incidence of early acute rejection (5/10 vs 22/69). Thirty-three (42%) of the patients received transplants from marginal donors, four of whom died during surgery; two died of acute vascular rejection, one of allograft failure caused by prolonged ischemic time, and one of bleeding secondary to preoperative sepsis and coagulopathy. These results show that heart transplantation may be performed in marginal recipients and donors, with acceptable operative mortality.

The fas and fas ligand pathways in liver allograft tolerance

The Fas and Fas ligand (Fas/FasL) pathways may play a central role in cytotoxicity or immunoregulation in liver transplantation. Here, in an attempt to examine the role of Fas/FasL on drug-free tolerance, we measured mRNA levels of Fas/FasL in livers by reverse transcriptase-polymerase chain reaction (RT-PCR), and also protein levels of Fas/FasL in livers by immunohistochemistry and in serum by dot blot assay. PVG recipients bearing DA livers showed serious rejection between post-operative (POD) days 7 and 14, but this rejection was naturally overcome without any immunosuppression. Fas gene and protein products were expressed on almost every cell in livers taken from naive rats, and at any time point in both syngeneic and allogeneic orthotopic liver transplantation (OLT) rats. In contrast, FasL mRNA in DA livers was detectable at POD 2, peaked at POD 14, and declined at POD 63 in allogeneic OLT (DA-PVG). Although the FasL gene was detectable in isografts at POD 14, its expression was much lower than in allografts. The time course and localization of FasL expression indicated that the expression of FasL gradually switched from infiltrating cells to hepatocytes when the rejection was naturally overcome and tolerance was induced in this OLT model. Soluble Fas could constitutively be detected at any time point in the serum of the tolerogenic OLT (DA-PVG) rats and was not diminished during the rejection phase. Soluble FasL peaked at POD 14 in allogeneic OLT, while sFasL was significantly lower in the serum of normal and syngeneic OLT rats. These findings suggest that the Fas and FasL pathways, including soluble forms, may contribute to the control of the immune response in this drug-free tolerance OLT model.

Total intravenous anesthesia using propofol and ketamine for ambulatory gynecologic laparoscopy

Laparoscopy under total intravenous anesthesia (TIVA) with spontaneous respiration is a commonly encountered procedure in ambulatory gynecologic surgery. The purpose of this study was to evaluate the efficacy of TIVA using propofol and ketamine, compared with endotracheal inhalational general anesthesia (EIGA) for ambulatory gynecologic laparoscopy. Fifty-eight female patients, aged 17-48 years, were randomly allocated into two groups. Group 1 (TIVA) (n = 28) received propofol at the induction of anesthesia followed by propofol infusion for maintenance. Intravenous ketamine 0.5 mg/kg was administered before operation for anesthetic effect. Natural airway and spontaneous breathing were then maintained in patients. Group 2 (n = 30) received EIGA with isoflurane under controlled ventilation. We found that the two groups demonstrated similar trend characters of pH and PaCO2 during operation and in recovery room. The incidence of postoperative vomiting was higher in group 2 than in group 1 (30% vs. 7%; p < 0.05). The incidence of intraoperative arrhythmia was higher in group 2 than in group 1 (40% vs. 3%; p < 0.001). Furthermore, the incidence of sore throat was higher in group 2 than in group 1 (47% vs. 7%; p < 0.001). We conclude that TIVA with spontaneous respiration is suitable for ambulatory gynecologic laparoscopy.

Magnetic resonance of the hepatic veins with angular reconstruction: application in living-related liver transplantation

BACKGROUND

Preoperative mapping of the hepatic venous system of the partial liver graft is indispensable to the success of living-related liver transplantation. We assessed the accuracy of magnetic resonance (MR) venography with angular reconstruction in depicting the tributaries of the middle hepatic vein and left hepatic vein in the donors, which was essential in graft retrieval and venoplasty.

METHODS

Nineteen living-related liver transplantation donors underwent a pretransplantation survey, including sonography and MRI for hepatic venous evaluation. T1-weighted images were reconstructed manually, using the inferior vena cava as a fixed point for tilting to produce an oblique plane image where both the middle hepatic vein and left hepatic vein could be demonstrated draining into the inferior vena cava. The reconstructed images of the hepatic veins were compared with preoperative sonography, intraoperative sonography, and operative findings.

RESULTS

Preoperative sonography and MR findings correlated well with the operative findings in the major hepatic veins. The MR venography of the ramification of the hepatic veins has an accuracy of 93%, the sonography, 84%. Sonography is slightly inferior in the evaluation of the hepatic vein in segment 4 and the left superior hepatic vein, with an accuracy of 73% and 67%, respectively.

CONCLUSION

MR venography with angular reconstruction is accurate in depicting the complex distribution of the hepatic veins of the left liver, providing important information for decision making as to the cutting plane during graft retrieval and the method of venoplasty and anastomosis. Thus, unnecessary blood loss could be avoided and vascular complications could be prevented, as these conditions would be unacceptable for a healthy living donor. We propose that MR venography, a rapid and reliable technique, is an appropriate alternative examination or complementary modality to sonography in the pretransplantation evaluation of the living donor.

Measurement of funny current (I(f)) channel mRNA in human atrial tissue: correlation with left atrial filling pressure and atrial fibrillation

INTRODUCTION

The funny current (I(f)) contributes to phase IV spontaneous depolarization in cardiac pacemaker tissue. Enhanced I(f) activity in myocardial tissue may lead to increased automaticity and therefore tachyarrhythmia. We measured the amount of I(f) activity in the messenger ribonucleic acid (mRNA) in human atrial tissue and correlated the mRNA amount to left atrial filling pressure and atrial fibrillation (AF).

METHODS AND RESULTS

A total of 34 patients undergoing open heart surgery were included (15 men and 19 women, aged 55+/-10 years). Atrial tissue was obtained from the right atrial free wall, the right atrial appendage, the left atrial free wall, and the left atrial appendage, respectively. The mRNA amount of the I(f) channel was measured by reverse transcription polymerase chain reaction and was normalized to the mRNA levels of glyceraldehyde 3-phosphate dehydrogenase. We found that the I(f) channel mRNA was present at all the atrial sampling sites. A higher left atrial filling pressure, an indicator of congestive heart failure, was associated with a higher I(f) mRNA level (r2 = 0.446, P < 0.01 by linear regression). We also found that the mRNA amount was significantly higher in patients with AF than in patients without AF (1.68+/-0.49 vs 1.27+/-0.43; P < 0.05). Age, sex, right atrial filling pressure, left atrial dimension, and left ventricular ejection fraction had no significant effect on the mRNA level.

CONCLUSION

The mRNA of the I(f) channel is present in the free-wall area and appendage area from both atria. Increased left atrial filling pressure and clinical AF are associated with increased I(f) mRNA level.

Once daily isepamicin treatment in complicated urinary tract infections

Isepamicin is a new aminoglycoside, derived from gentamicin B, which is more stable than other aminoglycosides against inactivating enzymes, and is less nephrotoxic. We evaluated the efficacy and safety of a once daily isepamicin in the treatment of complicated urinary tract infections (UTIs), as compared with amikacin. During the period May, 1997, to January, 1998, a total of 52 patients with similar demographic and baseline characteristics were enrolled into a prospective, randomized, open-label, single-center trial at the Veterans General Hospital-Kaohsiung. Eleven patients were excluded for protocol violation. The remaining 41 patients were included in the efficacy analysis. Study subjects included 16 men and 25 women, with a mean age of 57.9 (range 18-95) years. Clinical improvement was noted in 100% of patients in both the isepamicin and amikacin group. No statistically significant difference was observed between the 2 groups in regard to the rapidity of defervescence, relief of dysuria and urinary frequency, and clearance of bacteriuria and pyuria. Bacteriological cure rates were 89.4% for the isepamicin group and 100% for the amikacin group. Fifteen of 25 subjects who received isepamicin and 16 of 27 subjects who received amikacin had an adverse effect, all of which were considered to be mild except for one in the amikacin group, who had an adverse event of moderate severity (vomiting). Seven (3 isepamicin and 4 amikacin) adverse events were considered probably or possibly related to the study drug, which included eosinophilia (2 isepamicin), liver function impairment (1 isepamicin, 2 amikacin), renal function impairment (1 amikacin) and flushed face (1 amikacin). However, none of the patients had a life-threatening or severe adverse event that required discontinuation of the drug. These results show that once daily administration of isepamicin is as effective and safe as amikacin in treatment of complicated UTIs.

Unpreconditioned free revascularized dynamic cardiomyoplasty. Is it feasible?

BACKGROUND

Cardiomyoplasty is a new ventricular bioassist device for myocardial failure. But there are some limitations in standard cardiomyoplasty, such as the orientation of the muscle and fiber and the efficiency of the contractile segment of the flap. Free revascularized latissimus dorsi flap may be a good idea for solving these problems.

METHODS

We designed a canine free latissimus dorsi flap by revascularizing the flap with the left internal thoracic vessels by micro-surgical technique. Group I (n = 3) as control was performed by standard cardiomyoplasty, and the Group II (n = 10) was performed by the revascularized method. The heart was then wrapped by the revacularized flap. Group II was divided into IIa (n = 6, no pre-treatment before revascularization) and IIb (n = 4, normal saline pre-treatment before revascularization) by the different preservation methods. Hemodynamic data were recorded.

RESULTS

Group I all survived the 8-week training period. But Group II, Group IIa and IIb, all died in 3 days, but survived more than 12 hours. The hemodynamic analysis in Group I did not show any significant change except left ventricular end diastolic pressure. It showed elevated left ventricular pressure when the cardiostimulator was ON.

CONCLUSIONS

According to the result of this experiment, it seemed impossible to get a satisfactory result of more than 3 days for free revascularized cardiomyoplasty at present. There were a lot of problems waiting to be solved, such as preservation method during ischemia, bulky mass of the flap, and the potential problem of neuromuscular atrophy.

Down-regulation of L-type calcium channel and sarcoplasmic reticular Ca(2+)-ATPase mRNA in human atrial fibrillation without significant change in the mRNA of ryanodine receptor, calsequestrin and phospholamban: an insight into the mechanism of atrial electrical remodeling

OBJECTIVES

We investigated the gene expression of calcium-handling genes including L-type calcium channel, sarcoplasmic reticular calcium adenosine triphosphatase (Ca(2+)-ATPase), ryanodine receptor, calsequestrin and phospholamban in human atrial fibrillation.

BACKGROUND

Recent studies have demonstrated that atrial electrical remodeling in atrial fibrillation is associated with intracellular calcium overload. However, the changes of calcium-handling proteins remain unclear.

METHODS

A total of 34 patients undergoing open heart surgery were included. Atrial tissue was obtained from the right atrial free wall, right atrial appendage, left atrial free wall and left atrial appendage, respectively. The messenger ribonucleic acid (mRNA) amount of the genes was measured by reverse transcription-polymerase chain reaction and normalized to the mRNA levels of glyceraldehyde 3-phosphate dehydrogenase.

RESULTS

The mRNA of L-type calcium channel and of Ca(2+)-ATPase was significantly decreased in patients with persistent atrial fibrillation for more than 3 months (0.36+/-0.26 vs. 0.90+/-0.88 for L-type calcium channel; 0.69+/-0.42 vs. 1.21+/-0.68 for Ca(2+)-ATPase; both p < 0.05, all data in arbitrary unit). We further demonstrated that there was no spatial dispersion of the gene expression among the four atrial tissue sampling sites. Age, gender and underlying cardiac disease had no significant effects on the gene expression. In contrast, the mRNA levels of ryanodine receptor, calsequestrin and phospholamban showed no significant change in atrial fibrillation.

CONCLUSIONS

L-type calcium channel and the sarcoplasmic reticular Ca(2+)-ATPase gene were down-regulated in atrial fibrillation. These changes may be a consequence of, as well as a contributory factor for, atrial fibrillation.

Cardiorespiratory response of heart transplantation recipients to exercise in the early postoperative period

In this study, we evaluated the cardiorespiratory function of orthotopic heart transplantation (OHT) recipients during exercise. Seventeen male OHT recipients, ranging in age from 22 to 60 years, participated in this study 47 +/- 21 days after surgery. The control group consisted of 17 sedentary healthy men. Breath-by-breath measurement of cardiorespiratory function was obtained during the incremental exercise of leg cycling. At peak exercise, the oxygen (O2) uptake (16.5 +/- 3.3 vs 33.9 +/- 8.2 mL.kg-1.min-1), work rate (82 +/- 19 vs 169 +/- 42 watts), heart rate (HR), O2 pulse, and blood lactate level of the OHT recipients were significantly lower than the respective values of the control group. At the ventilatory threshold, the OHT group also showed a significantly lower O2 uptake (10.7 +/- 1.6 vs 18.3 +/- 5.1 mL.kg-1.min-1), work rate (39 +/- 12 vs 89 +/- 33 watts), HR, O2 pulse, ventilatory equivalent for O2, and ventilatory equivalent for carbon dioxide. The OHT recipients showed a high resting HR (97 +/- 7 beats/min) and a low peak HR (123 +/- 14 beats/min) during exercise, and their HR continued to increase for 1 to 3 minutes after cessation of exercise. Our data revealed a low level of cardiorespiratory endurance in OHT recipients during the early postoperative stage. A multidisciplinary cardiac rehabilitation program should be considered to enhance physical functional capacity and quality of life, and promote return to work.

Effects of basic fibroblast growth factor (bFGF)-neutralizing antibody and platelet factor 4 on facial nerve regeneration

Exogenous basic fibroblast growth factor (bFGF) has been shown to prevent death of injured cholinergic neurons and stimulate neurite outgrowth from the proximal stump of the transected sciatic nerve. The present study was designed to examine the role of endogenous bFGF, rather than exogenous bFGF in the regenerative process of the transected facial nerve of guinea pig, by using the so-called silicone tubulization model which enabled us to bridge the transected facial nerve with a silicone tube and to inject into the tube bFGF-neutralizing antibody, normal IgG, saline, or platelet factor 4 (an antagonist for bFGF receptor). Under light microscopy, treatment with bFGF-neutralizing antibody caused significant decreases in vascular number, vascular area, and regenerating axons in the middle point of regeneration chambers at the third week after facial nerve transection, even though electron microscopy revealed that the bFGF-neutralizing antibody increased the number of thin axons with caliber smaller than 1 micrometer. Treatment with platelet factor 4 exhibited similar but more conspicuous effects on facial nerve regeneration. These findings suggest that endogenous bFGF not only facilitates angiogenesis within the transected facial nerve but also acts as a neurotrophic agent during facial nerve regeneration; it appears that endogenous bFGF contributes to the enlargement of axon caliber and increases the number of relatively large caliber axons.

A novel spliced transcript of influenza A/WSN/33 virus

It has been shown that influenza A virus M1 mRNA has two alternative 5" splice sites: a distal 5" splice site producing M3 mRNA that has the coding potential for 9 amino acids and a proximal 5" splice site producing M2 mRNA that encodes the essential M2 ion-channel protein. In this study, we demonstrated that the laboratory widely used strain A/WSN/33, but not A/Udorn/72 possessed another novel 5" splice site producing a transcript with the coding potential for 54 amino acids. We nominated this novel transcript as M4 mRNA. M4 mRNA was detected in A/WSN/33-infected cells derived from different species. Sequence comparison of M1 mRNA in both A/WSN/33 and Udorn/72 at position 143 to 151 reveals that this novel 5" splice site generated in WSN was due to one nucleotide difference at position 147. Several strains of influenza A viruses other than WSN also possess the potential M4 5" splice site by sequence analysis from the files of GenBank.

A transient increase in endogeneous erythropoietin levels after paediatric liver transplantation

We investigated whether liver transplantation affects endogeneous erythropoietin (EPO) synthesis. Serum EPO levels were measured before transplantation and during the peri-transplant period in ten consecutive paediatric patients who had received a liver allograft without recombinant EPO therapy. All patients were anaemic on post-operative day 1 (POD 1); however, the haemoglobin levels of three patients gradually increased and required phlebotomy on POD 5-9. The serum levels of EPO in all patients were within the normal range before surgery, but six of the ten patients had a transient increased level of EPO at 1248 h after transplantation. A transient increase of endogeneous EPO following paediatric liver transplantation may be associated with extramedullary erythropoiesis in human liver grafts.