P4660Lipoprotein particle profiles compared with standard lipids in the association with sub-clinical aortic valve calcification in apparently healthy Japanese men

Introduction

Calcific aortic valve disease (CAVD) is one of the most common heart diseases worldwide, and its prevalence has increased in developed countries along with aging populations. Subclinical CAVD is characterized by aortic valve calcification (AVC) that may lead to aortic stenosis. AVC shares the same risk factors with atherosclerotic disease. Recently, nuclear magnetic resonance (NMR)-based lipoprotein particles, low-density and high-density lipoprotein particles (LDL-p, HDL-p) in particular, have emerged as novel markers of atherosclerotic disease. It has been unclear, however, whether NMR-based particles are associated with AVC.

Purpose

To examine cross-sectional association of NMR-based lipoprotein particles, standard lipids with AVC, and compare their strengths of association.

Methods

We studied a community-based random sample of Japanese men aged 40–79 years examined in 2006–08 in Japan. We excluded participants with history of myocardial infarction, stroke, aortic valve surgery, serum triglyceride concentration ≥400 mg/dl, estimated glomerular filtration rate (eGFR) <30 (ml/min/1.73m2), and use of lipid-lowering medication. We scored the degree of AVC according to Agatston's method, and defined prevalent AVC as the score >0. Lipoprotein particles were measured using NMR spectroscopy.

In our main analysis, we obtained multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (95% CI) of prevalent AVC in the top quartile (Q4) for each lipid index in reference to the lowest quartile (Q1). Adjusting covariates include age, smoking, drinking, systolic blood pressure, glycated hemoglobin, medications for hypertension and/or for diabetes, eGFR, C-reactive protein. For sensitivity analysis, we repeated similar analyses presenting ORs per 1 standard deviation (SD) higher NMR-lipoproteins particles or standard lipids.

Results

Of 874 participants we analyzed, 153 (17.5%) men had AVC. The average (SD) age was 63.3 (10.0) years. Those with AVC tended to be older, likely to have clustering of atherosclerotic risk factors. Multivariable-adjusted ORs of prevalent AVC for Q4 versus Q1 were significantly positive for LDL-p [OR, 2.21 (95% CI: 1.24, 3.95] and low-density lipoprotein cholesterol (LDL-c) [2.17 (1.24, 3.80)]. In contrast, neither HDL-p nor high-density lipoprotein cholesterol (HDL-c) was significantly associated with AVC. In sensitivity analyses, however, the corresponding ORs per 1SD higher lipids/lipoprotein particles were smaller in LDL-p [1.33 (1.09, 1.63)] than LDL-c [1.41 (1.15, 1.73)]. The association of HDL-p became significant [1.28 (1.02, 1.61)] (per 1SD decrement) in the sensitivity analysis.

Conclusion

The overall associations of AVC with NMR-based lipoprotein particles (i.e. LDL-p, HDL-p) are comparable to those of standard lipids. This finding is parallel to the association between atherosclerotic cardiovascular diseases with NMR-based lipoproteins.

A first-principles prediction on the "healing effect" of graphene preventing carrier trapping near the surface of metal halide perovskites

We introduce a healing effect of graphene preventing carrier trapping by the defects near the surface of metal halide perovskites.

We herein report that surface modification of metal halide perovskites using graphene would be beneficial to improving the energy conversion efficiencies of perovskite solar cells. The present first-principles calculations on MAPbI₃ with a single vacancy created by removing either I, Pb or MA show that the I and Pb vacancies near the surface result in the formation of Pb–Pb and I–I dimers, respectively. They are predicted to yield mid-gap levels, and would degrade the energy conversion efficiency of perovskite solar cells through carrier trapping. The present calculations suggest that when the surface of MAPbI₃ is covered with a graphene sheet, the formation of the carrier trapping dimers would be suppressed. The origin of the “healing effect” of graphene on the lattice defect is ascribed to electronic interactions on the surface, which prevent charge localization at the lattice defects beneath the surface.

Effect of arginine vasopressin on systemic and pulmonary arterial pressure in a patient with pulmonary hypertension secondary to pulmonary emphysema: a case report

Although data from several studies support the use of arginine vasopressin (AVP) for the treatment of hypotension concomitant with pulmonary hypertension (PH) in the cardiac surgery setting, to our knowledge, no previous studies have reported the effect of AVP on the systemic and pulmonary circulation of patients with PH secondary to lung diseases. In this report, we present the hemodynamic responses to bolus administrations of AVP and noradrenaline in a patient with PH secondary to pulmonary emphysema. The patient showed low systemic vascular resistance hypotension during off-pump single-lung transplantation. The bolus administration of AVP (0.5 U) increased systemic arterial pressure by 35.2%, with a minimal change in pulmonary arterial pressure, resulting in a significant decrease in the pulmonary arterial pressure/systemic arterial pressure ratio. In contrast, the bolus administration of noradrenaline (10 or 20 μg) increased both systemic and pulmonary arterial pressures by 14.8 and 6.7%, respectively. In summary, the bolus administration of AVP effectively increased systemic arterial pressure with a minimal effect on pulmonary arterial pressure in a patient with PH secondary to pulmonary emphysema. This case highlights the potential utility of AVP to treat low systemic vascular resistance hypotension in patients with PH secondary to lung diseases.

Relationship Between Intraoperative Hypotension and Acute Kidney Injury After Living Donor Liver Transplantation: A Retrospective Analysis

OBJECTIVE

Acute kidney injury (AKI) is common after liver transplantation (LT) and has a significant impact on outcomes. Although several risk factors for post-LT AKI have been identified, the effect of intraoperative hemodynamic status on post-LT AKI remains unknown. Therefore, the authors aimed to investigate the relationship between hemodynamic parameters during LT and postoperative AKI.

DESIGN

A retrospective observational study.

SETTING

University hospital.

PARTICIPANTS

Patients who underwent living donor LT (n = 231).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Severe AKI (stages 2-3 according to recent guidelines) was the primary outcome. Multivariable logistic regression analysis was used to control for confounding variables to obtain the independent relationship between intraoperative hemodynamic parameters (mean arterial pressure [MAP] and cardiac index) and severe AKI. The prevalence of severe AKI was 30.7%. Nadir MAP during the surgery was independently predictive of severe AKI (adjusted odds ratio, 2.11 [95% confidence interval, 1.32-3.47] per 10-mmHg decrease; p = 0.002). Subgroup analyses based on various patient or operative variables and extensive sensitivity analyses showed substantially similar results. Severe hypotension (MAP<40 mmHg), even for fewer than 10 minutes, was related significantly to severe AKI (adjusted odds ratio, 3.80 [95% confidence interval, 1.17-12.30]; p = 0.026). In contrast, nadir cardiac index was not related significantly to severe AKI.

CONCLUSIONS

The authors found an independent relationship between degree of intraoperative hypotension and risk of severe AKI in living donor LT recipients. Severe hypotension, even for a short duration, was related significantly to severe AKI.

[Difficult Ventilation Requiring Emergency Endotracheal Intubation during Awake Craniotomy Managed by Laryngeal Mask Airway]

We report a case of difficult ventilation requiring emergency endotracheal intubation during awake craniotomy managed by laryngeal mask airway (LMA). A 45-year-old woman was scheduled to receive awake craniotomy for brain tumor in the frontal lobe. After anesthetic induction, airway was secured using ProSeal LMA and patient was mechanically ventilated in pressure-control mode. Patient's head was fixed with head-pins at anteflex position, and the operation started. About one hour after the start of the operation, tidal volume suddenly decreased. We immediately started manual ventilation, but the airway resistance was extremely high and we could not adequately ventilate the patient. We administered muscle relaxant for suspected laryngospasm, but ventilatory status did not improve; so we decided to conduct emergency endotracheal intubation. We tried to intubate using Airwayscope or LMA-Fastrach, but they were not effective in our case. Finally trachea was intubated using transnasal fiberoptic bronchoscopy. We discuss airway management during awake craniotomy, focusing on emergency endotracheal intubation during surgery.

A malignant hyperthermialike episode in a liver transplant recipient

We report a case of malignant hyperthermialike syndrome in a living-donor liver transplant recipient with no familial history of malignant hyperthermia or exposure to known triggering drugs. The patient showed many features of a typical malignant hyperthermia episode, and The Clinical Grading Scale defined this case as almost certain to be an episode of malignant hyperthermia (rank 5). However, the diagnosis was questionable. The intraoperative and perioperative periods during liver transplant can involve drastic alterations of physiological parameters, which can make malignant hyperthermia difficult to diagnosis. The data we obtained using a pulmonary artery catheter suggest an intraoperative increase in systemic oxygen consumption.

Living-donor liver transplantation for congenital biliary atresia with porto-pulmonary hypertension and moderate or severe pulmonary arterial hypertension: Kyoto University experience

Porto-pulmonary hypertension with moderate or severe pulmonary arterial hypertension (PAH) is viewed as a contraindication to liver transplantation (LT) because of associated poor outcomes; however, patients with biliary atresia (BA) are generally good candidates for LT. Ten patients with moderate/severe PAH underwent living-donor liver transplantation (LDLT) at our institution; eight of these patients had BA and were the focus of this study. Preoperative therapies, including prostaglandin (PG)I2 , were introduced. When mean pulmonary arterial pressure (mPAP) after treatment was <40 mmHg or initial mPAP without therapy was <35 mmHg, we performed an acute volume challenge test to evaluate right ventricular function. LDLT was performed when mPAP after anesthetic induction was confirmed at ≤35 mmHg. Six patients had favorable responses to preoperative treatment and catheter testing, but two patients showed poor responses. The two patients with poor responses had poor clinical courses with unstable mPAP after LDLT. The other six patients had successful courses with well-controlled mPAP, and PGI2 was withdrawn or weaned following LDLT. Survival did not significantly differ between the eight BA recipients with moderate/severe PAH and 77 age-matched BA recipients without PAH from the same time period. LDLT has major benefits for BA patients with well-controlled PAH.

How do transplant surgeons accomplish optimal portal venous flow during living-donor liver transplantation? Noninvasive measurement of indocyanine green elimination rate

BACKGROUND

Balancing donor safety and graft volume is difficult. We previously reported that intentional modulation of portal venous pressure (PVP) during living-donor liver transplantation (LDLT) is crucial to overcoming problems with small-for-size grafts; however, detailed studies of portal venous flow (PVF) and a reliable parameter are still required.

PATIENTS AND METHODS

The elimination rate (k) of indocyanine green (ICG) was measured in 49 adult LDLT recipients. PVP was controlled during LDLT, with a target of <20 mm Hg. ICG reflects hepatocyte volume and effective PVF. The kICG value is divided by the graft weight to calculate PVF. Recipients were divided into 2 groups: those with severe and/or fatal complications within 1 month after LDLT and those without.

RESULTS

Survival rates and postoperative profiles were significantly different between the 2 groups. Univariate analysis showed significant differences in ABO blood group, final PVP, final kICG, and the final kICG/graft weight value; however, multivariate analysis showed that only the kICG/graft weight value was significant. The cutoff level for the final kICG/graft weight value for predicting successful LDLT was 3.1175 × 10(-4)/g.

CONCLUSION

Accurate evaluation and monitoring of optimal PVF during LDLT should overcome the use of small-for-size grafts and improve donor safety and recipient outcomes.

How transplant surgeons can overcome the inevitable insufficiency of allograft size during adult living-donor liver transplantation: strategy for donor safety with a smaller-size graft and excellent recipient results

Small-for-size grafts are an issue in liver transplantation. Portal venous pressure (PVP) was monitored and intentionally controlled during living-donor liver transplantation (LDLT) in 155 adult recipients. The indocyanine green elimination rate (kICG) was simultaneously measured in 16 recipients and divided by the graft weight (g) to reflect portal venous flow (PVF). The target PVP was <20 mmHg. Patients were divided by the final PVP (mmHg): Group A, PVP < 12; Group B, 12 ≤ PVP < 15; Group C, 15 ≤ PVP < 20; and Group D, PVP ≥ 20. With intentional PVP control, we performed splenectomy and collateral ligation in 80 cases, splenectomy in 39 cases, and splenectomy, collateral ligation, and additional creation in five cases. Thirty-one cases received no modulation. Groups A and B showed good LDLT results, while Groups C and D did not. Final PVP was the most important factor for the LDLT results, and the PVP cutoffs for good outcomes and clinical courses were both 15.5 mmHg. The respective kICG/graft weight cutoffs were 3.5580 × 10(-4) /g and 4.0015 × 10(-4) /g. Intentional PVP modulation at <15 mmHg is a sure surgical strategy for small-for-size grafts, to establish greater donor safety with good LDLT results. The kICG/graft weight value may have potential as a parameter for optimal PVF and a predictor for LDLT results.

Use of noninvasive ventilation for pediatric patients after liver transplantation: decrease in the need for reintubation

Noninvasive ventilation (NIV) refers to ventilation delivered through a noninvasive interface (a nasal or face mask) rather than an invasive interface (an endotracheal tube or tracheostomy). The role of NIV in preventing reintubation after abdominal surgery in pediatric patients is uncertain. Therefore, we evaluated the role of NIV for this purpose in pediatric patients after liver transplantation. We successfully started using NIV for respiratory complications (RCs) in pediatric patients undergoing liver transplantation in 1999. For this report, we screened all medical records of patients under the age of 12 years who underwent liver transplantation between 2001 and 2009, and we retrieved data for cases at high risk of extubation failure. We retrospectively compared the clinical outcomes of patients who received NIV during their intensive care unit (ICU) stay and patients who did not. Data for 94 cases (92 patients) were included in this analysis. NIV was used in 47 patients during their ICU stay. The rate of reintubation for RCs was significantly lower in NIV patients versus non-NIV patients [3/47 (6.4%) versus 11/47 (23.4%), P = 0.02]. Furthermore, the discharge rate from the ICU was significantly better for NIV patients versus non-NIV patients. The use of NIV after extubation prevented the worsening of atelectasis and stabilized respiratory conditions in this cohort. No major changes in operative procedures or other treatments during the examined period were found. In conclusion, NIV is acceptable and promising for the respiratory management of pediatric patients undergoing liver transplantation. Its use may stabilize respiratory conditions and decrease the need for reintubation in pediatric liver transplant patients, and it may also facilitate an early ICU discharge.

Thrombotic microangiopathy-like disorder after living-donor liver transplantation: A single-center experience in Japan

AIM: To investigate thrombotic microangiopathy (TMA) in liver transplantion, because TMA is an infrequent but life-threatening complication in the transplantation field.

METHODS: A total of 206 patients who underwent living-donor liver transplantation (LDLT) were evaluated, and the TMA-like disorder (TMALD) occurred in seven recipients.

RESULTS: These TMALD recipients showed poor outcomes in comparison with other 199 recipients. Although two TMALD recipients successfully recovered, the other five recipients finally died despite intensive treatments including repeated plasma exchange (PE) and re-transplantation. Histopathological analysis of liver biopsies after LDLT revealed obvious differences according to the outcomes. Qualitative analysis of antibodies against a disintegrin-like domain and metalloproteinase with thrombospondin type 1 motifs (ADAMTS-13) were negative in all patients. The fragmentation of red cells, the microhemorrhagic macules and the platelet counts were early markers for the suspicion of TMALD after LDLT. Although the absolute values of von Willebrand factor (vWF) and ADAMTS-13 did not necessarily reflect TMALD, the vWF/ADAMTS-13 ratio had a clear diagnostic value in all cases. The establishment of adequate treatments for TMALD, such as PE for ADAMTS-13 replenishment or treatments against inhibitory antibodies, must be decided according to each case.

CONCLUSION: The optimal induction of adequate therapies based on early recognition of TMALD by the reliable markers may confer a large advantage for TMALD after LDLT.

Omission of fentanyl during sevoflurane anesthesia decreases the incidences of postoperative nausea and vomiting and accelerates postanesthesia recovery in major breast cancer surgery

PURPOSE

Our purpose was to investigate the effect of omission of fentanyl during sevoflurane anesthesia on the incidences of postoperative nausea and vomiting and on postanesthesia recovery in female patients undergoing major breast cancer surgery.

METHODS

Female patients (American Society of Anesthesiologists [ASA] physical status [PS] class I-II; age, 28-84 years) undergoing major breast cancer surgery were randomized to one of two anesthesia maintenance groups: sevoflurane-fentanyl anesthesia (SF; n = 25) or fentanyl-free sevoflurane anesthesia (S; n = 26). All patients were administered with propofol 2 mg x kg(-1) intravenously for anesthesia induction, a laryngeal mask airway was placed, and they received rectal diclofenac and local infiltration anesthesia. Anesthesia was maintained with sevoflurane in oxygen-air and they breathed spontaneously. The patients in group SF received fentanyl 0.1 mg intravenously and those in group S received normal saline during anesthesia.

RESULTS

Group SF revealed higher incidences of postoperative nausea (68% vs 27%) and vomiting (32% vs 8%) in the first 24 postoperative hours than group S. The median (25th-75th percentile) length of time from postanesthesia care unit (PACU) admission to ambulation was significantly longer in group SF (n = 23) at 195 min (158-219 min), than in group S, at 141 min (101-175 min). Two patients in group SF could not walk during the PACU stay.

CONCLUSION

Omission of fentanyl during sevoflurane anesthesia, combined with diclofenac and local infiltration anesthesia, decreases the incidences of postoperative nausea and vomiting and accelerates postanesthesia recovery in patients undergoing major breast cancer surgery.

A third-generation bisphosphonate, minodronic acid (YM529), successfully prevented the growth of bladder cancer in vitro and in vivo

Minodronic acid (YM529) is a third-generation bisphosphonate (BP) that has been shown to directly and indirectly prevent proliferation, induce apoptosis, and inhibit metastasis of various types of cancer cells. In this study, we have investigated the therapeutic efficacy of YM529 against bladder cancer, both in vitro and in vivo. YM529 inhibited geranylgeranylation as well as farnesylation and reduced the growth of all seven bladder cancer cell lines in a dose- and time-dependent manner in vitro. YM529 demonstrated a good synergistic or additive antiproliferative effect when administered in combination with cisplatin or paclitaxel. Immunohistochemical study revealed YM529 inhibited the prenylation of Rap1A in vivo. YM529 administered systemically did not markedly inhibit the growth of visceral metastases but it showed a significant anticancer effect on bone metastases monitored by an in vivo imaging system. Moreover, intravesical YM529 demonstrated significant growth inhibition in a bladder cancer orthotopic model. No adverse effects were associated with the systemic as well as the intravesical treatment regimens. In conclusion, our study suggests that YM529 may be a potent anticancer agent for bladder cancer. The efficacy and safety of this BP as an agent for combination chemotherapies against bladder cancer should be verified by early-phase clinical trials.

Improved photocatalytic activity of zeolite- and silica-incorporated TiO2 film

Porous TiO2 film was prepared by sol-gel method from TiO2 sol containing polyvinylpyrolidone (PVP). Photocatalytic activity of the film was evaluated by the elimination rate of ethylene. Several adsorbents including zeolite and silica powders were incorporated into the TiO2 film. All the adsorbents enhanced the activity. The optimum adsorbent content was 0.005-0.01 g/ml of the coating sol solution. Silica provided better activity than zeolite. At high humidity and in dry air the activity decreased.

The role of CRF1 receptors for sympathetic nervous response to laparotomy in anesthetized rats

Corticotropin-releasing factor (CRF) is released in response to various types of stressors and mediates endocrine, autonomic, immune, and behavioral responses to stress through interaction with CRF1 and CRF2 receptors. To investigate the role of CRF1 receptors in physiological responses to surgical stress, we analyzed the effects of two different non-peptide selective CRF1 receptor antagonists (JTC-017 and CP-154,526) and a peptide non-selective CRF receptor antagonist (astressin) on laparotomy-induced sympathetic nervous responses in isoflurane-anesthetized rats. JTC-017, CP-154,526, and astressin similarly suppressed plasma ACTH elevation induced by laparotomy. JTC-017 and CP-154,526 significantly augmented plasma noradrenaline and adrenaline responses to laparotomy, while astressin showed no effect on these responses. Laparotomy-induced maximum increases in mean blood pressure and heart rate were augmented by JTC-017, but were not affected by astressin. The results suggested for the first time that there was a pathway to attenuate sympathetic nervous response to surgical stress through CRF1 receptors in the central nervous system.

[Perioperative management of living-donor liver transplantation in two patients with severe portopulmonary hypertension]

Liver transplantation for patients with severe portopulmonary hypertension (PPHTN) has been associated with high mortality. We conducted perioperative management of two patients with severe PPHTN for living-donor liver transplantation. The first case was a 17-year-old male with biliary atresia. He developed dyspnea at the age of 14, for which he was treated with intravenous epoprostenol for 8 months. As a result, the mean pulmonary artery pressure (MPAP) was reduced from 61 to 40 mmHg. Intraoperatively, he was treated with intravenous epoprostenol and nitric oxide (NO) inhalation. His intraoperative course was uneventful but he died from right heart failure on postoperative day (POD) 11. The second case was a 6-year-old girl with biliary atresia. When she was 5 years old, examination for a persistent cough revealed MPAP of 49 mmHg. Neither intravenous epoprostenol nor NO inhalation was effective, and she twice showed transient pulmonary hypertension during the operation. She was extubated 14 hours after the surgery, transferred out of ICU on POD 3 and discharged from the hospital on POD 99. When we compare the two cases, the factors responsible for the success of the management of the second case appear to be early extubation and the short duration of PPHTN.

Potentiation of proopiomelanocortin gene expression in cultured pituitary cells by benzodiazepines

BACKGROUND

Benzodiazepines are frequently used not only as a part of general anesthesia but also for the purpose of sedation during regional anesthesia. Effects of these drugs on the hypothalamic-pituitary-adrenal axis activity have been studied, but are still controversial. It is not known whether benzodiazepines affect expression of proopiomelanocortin, precursor protein of adrenocorticotropic hormone and related peptides.

METHODS

AtT20PL cell line, a clone of AtT20/D16v mouse corticotroph tumor cells stably transfected with approximately 0.7 kilobases (kb) of the rat proopiomelanocortin 5' promoter-luciferase fusion gene, was used. In the presence or absence of diazepam or midazolam, cells were stimulated by corticotropin-releasing hormone (CRH) or forskolin. Proopiomelanocortin gene expression was estimated by measurement of luciferase activity. Furthermore, to study the mechanism of benzodiazepine effects, cyclic adenosine 3',5'-monophosphate (cyclic AMP) efflux was measured by enzyme immunoassay.

RESULTS

Diazepam and midazolam dose-dependently increased the proopiomelanocortin gene expression induced by CRH or forskolin. The potentiating effect was not affected by benzodiazepine receptor antagonists flumazenil and PK11195, but was abolished by a cyclic AMP-dependent protein kinase inhibitor H89. Cyclic AMP efflux induced by CRH or forskolin was also enhanced by diazepam and midazolam. In the presence of isobutylmethylxanthine, a nonspecific phosphodiesterase inhibitor, potentiation of proopiomelanocortin gene expression and enhancement of cyclic AMP efflux by benzodiazepines were not observed.

CONCLUSIONS

Benzodiazepines potentiate the effect of CRH or forskolin on proopiomelanocortin gene expression. The potentiating effect is not mediated by the benzodiazepine receptors, but its mechanism probably involves inhibition of phosphodiesterase.

Cloning, gene structure and dietary regulation of the type-IIc Na/Pi cotransporter in the mouse kidney

We have demonstrated previously that the type-IIc Na/Pi cotransporter is a growth-related renal Na/Pi cotransporter that is highly expressed in kidney of the weaning rat. In the present study, we investigated type-IIc Na/Pi cotransporter function further by cloning the mouse gene and characterizing the corresponding protein. The mouse type-IIc transporter amino acid sequence shows a high degree of similarity to the human (86%) and rat (95%) type-IIc Na/Pi-cotransporters. The mouse gene contained 14 exons and mapped to chromosome 2. The DNA sequence upstream from exon 1 is GC rich. The upstream region does not contain an apparent TATA box, but does contain two dietary Pi-responsive elements, which are potential binding sites for the transcription factor micro E3 (TFE3). Microinjection of mouse type-IIc cRNA into Xenopus oocytes demonstrated sodium-dependent Pi cotransport activity. The affinity for Pi was about 200 microM in 100 mM Na. Feeding adult mice fed a low-Pi diet increased the expression of type-IIc protein in the apical membrane of renal proximal tubular cells. Hybrid depletion studies suggested that the type-IIc transporter contributes to about 30% of Na/Pi cotransport in the kidney of adult mice fed a low-Pi diet. The present study suggests that the type-IIc Na/Pi cotransporter is a functional of renal Pi transporter in adult mice fed a low-Pi diet.

[Anesthesia for living-donor liver transplantation in a patient with adult polycystic liver disease]

Anesthesia for living-donor liver transplantation (LDLT) was performed for two patients with adult polycystic liver disease (APLD). APLD is characterized by gradual cystic transformation of both lobes of the liver. Abdominal enlargement, poor appetite, abdominal pain, infection of liver cysts and portal hypertension are symptoms of this disease. Liver transplantation is indicated as the final therapy. Our two patients had very large livers (7400 g and 9500 g). The second patient had suffered renal failure due to a polycystic kidney so that continuous hemodiafiltration had to be performed after surgery. In both cases, sudden hypotension frequently occurred during manipulation of the enlarged liver. In the first case, sudden massive bleeding occurred as a result of laceration of the middle and left hepatic vein when the liver was dropped from the surgeon's hand. In both cases, the position of endotracheal tube became 2 cm shallower after surgery probably because of the shift in the position of the mediastinum after elimination of abdominal compression caused by the enlarged liver. One patient was discharged 39 days and the other 115 days after surgery. Anesthesiologists should pay special attention to the features reported here during LDLT for patients with APLD.

Effects of xenon on acetylcholine release in the rat cerebral cortex in vivo

BACKGROUND

We have reported previously the effects of several anaesthetics on cholinergic activity in the central nervous system (CNS). In this study, we report the effects of xenon on cholinergic cell activity.

METHODS

Using in vivo brain microdialysis, we measured acetylcholine (ACh) release in the rat cerebral cortex in vivo during xenon anaesthesia.

RESULTS

Xenon induced an initial increase in ACh release, followed by a gradual decrease. The level of Ach release at 40 min of xenon administration was significantly higher than the control.

CONCLUSIONS

Xenon activates CNS cholinergic cell activity followed by development of acute tolerance.

Effects of propofol on lactate accumulation and oedema formation in focal cerebral ischaemia in hyperglycaemic rats

BACKGROUND

In cerebral ischaemia, hyperglycaemia brings about severe lactate accumulation and neuronal damage when compared with normoglycaemia. Propofol has been known to suppress glucose metabolism in the brain and possess neuroprotective properties in cerebral ischaemia. Therefore, in this study we examined if propofol could attenuate lactate accumulation and neuronal damage in cerebral ischaemia under hyperglycaemic conditions.

METHODS

Ten male wistar rats were divided into two experimental groups: low-dose (approximately 12 mg kg(-1) h(-1)) and high-dose (approximately 60 mg kg(-1) h(-1)) propofol groups (n=5 for each). Following injection of 2 g kg(-1) glucose intraperitoneally, the middle cerebral artery was occluded for 1 h, and then reperfused for the following 2 h. Lactate accumulation and oedema formation were estimated consecutively using nuclear magnetic resonance (NMR) techniques.

RESULTS

Lactate accumulation and oedema formation increased continuously during ischaemia and reperfusion in the low-dose propofol group, which was attenuated in the high-dose propofol group. Lactate/NAA (N-acetylaspartate) ratio (as an index of lactate accumulation) 60 and 120 min after reperfusion were 2.67 and 3.26 in low-dose group and 0.30 and 0.10 in high-dose group. For NMR images the number of pixels with a low average diffusion coefficient (an index of the oedema formation), 60 and 120 min after reperfusion were 250.0 and 317.8 in low-dose group, and 16.0 and 12.4 in high-dose group.

CONCLUSION

High-dose propofol attenuated lactate accumulation and oedema formation in cerebral ischaemia in hyperglycaemic rats.

Modulation of event-related potentials in normal human subjects by visual divided attention to spatial and color factors

We investigated how visual event-related potentials (ERPs) are modulated by visual divided attention using an S1-S2 paradigm. Stimulus S2 consisted of non-target stimuli (Stimulus 1, 2, 3) and a target stimulus (Stimulus 4). The spatial/color factor was compared between S1 and S2: same/same (Stimulus 1); same/different (Stimulus 2); different/same (Stimulus 3); and different/different (Stimulus 4). The P1/N1 (90 approximately 150 ms) showed significantly greater amplitude in Stimulus 3 than in Stimuli 1 and 2. The N2 (230 approximately 290ms) showed significantly greater amplitude in Stimulus 2 than in Stimuli 1 and 3. We assumed that the P1/N1 was related to spatial attention, enhanced by alterations to the spatial factor, and that the N2 was related to color attention, enhanced by alterations to the color factor.

Human L-type amino acid transporter 1 (LAT1): characterization of function and expression in tumor cell lines

System L is a major nutrient transport system responsible for the transport of large neutral amino acids including several essential amino acids. We previously identified a transporter (L-type amino acid transporter 1: LAT1) subserving system L in C6 rat glioma cells and demonstrated that LAT1 requires 4F2 heavy chain (4F2hc) for its functional expression. Since its oncofetal expression was suggested in the rat liver, it has been proposed that LAT1 plays a critical role in cell growth and proliferation. In the present study, we have examined the function of human LAT1 (hLAT1) and its expression in human tissues and tumor cell lines. When expressed in Xenopus oocytes with human 4F2hc (h4F2hc), hLAT1 transports large neutral amino acids with high affinity (K(m)= approximately 15- approximately 50 microM) and L-glutamine and L-asparagine with low affinity (K(m)= approximately 1.5- approximately 2 mM). hLAT1 also transports D-amino acids such as D-leucine and D-phenylalanine. In addition, we show that hLAT1 accepts an amino acid-related anti-cancer agent melphalan. When loaded intracellularly, L-leucine and L-glutamine but not L-alanine are effluxed by extracellular substrates, confirming that hLAT1 mediates an amino acid exchange. hLAT1 mRNA is highly expressed in the human fetal liver, bone marrow, placenta, testis and brain. We have found that, while all the tumor cell lines examined express hLAT1 messages, the expression of h4F2hc is varied particularly in leukemia cell lines. In Western blot analysis, hLAT1 and h4F2hc have been confirmed to be linked to each other via a disulfide bond in T24 human bladder carcinoma cells. Finally, in in vitro translation, we show that hLAT1 is not a glycosylated protein even though an N-glycosylation site has been predicted in its extracellular loop, consistent with the property of the classical 4F2 light chain. The properties of the hLAT1/h4F2hc complex would support the roles of this transporter in providing cells with essential amino acids for cell growth and cellular responses, and in distributing amino acid-related compounds.

[Cellular mechanisms in proximal tubular handling of phosphate]

In the kidney, reabsorption of filtered inorganic phosphate (Pi) takes place along the proximal tubules and is controlled by a variety of hormones (e.g.parathyroid hormone, PTH). Three structurally unrelated sodium-dependent phosphate (Na/Pi) cotransporter families have been identified. Targeted inactivation of the type IIa Na/Pi cotransporter gene (npt2) provided strong evidence that - 70% of Na-dependent Pi transport across the brush border membrane is mediated by the type IIa Na/Pi cotransporter. The type IIa cotransporter represents the major target for PTH. The type IIa cotransporter interacts with various PDZ proteins that might be responsible for the apical sorting, PTH controlled endocytosis or the lysosomal sorting internalized type IIa cotransporter.

Multiple osteochondroses of bilateral knee joints

We experienced a patient with a combination of multiple osteochondroses: Blount's disease, bipartite patella, and Sinding-Larsen-Johansson disease in the left knee, and a combination of bipartite patella and Osgood-Schlatter disease in the right knee. The patient was a healthy, active 12-year-old boy with bilateral knee pain. He had been diagnosed with Blount's disease of the left tibia at 2 years of age, and had been treated with open wedge osteotomy. He was diagnosed with bilateral bipartite patellae at the age of 9 years, and was diagnosed with Osgood-Schlatter disease in the right knee and Sinding-Larsen-Johansson disease in the left knee at 10 years of age. The second growth spurt was observed during this period. At 11 years of age, he was diagnosed with an osteochondral fracture of the left lateral femoral condyle and was observed without surgery. This patient showed the sequential appearance of an ossification disorder, probably due to the abnormal response of enchondral ossification to mechanical stress. Overuse in this growth period may have played a role in the development of these osteochondroses. The osteochondral fracture was probably caused by a disruption at one of the weakest parts of the developing skeleton, between the ossification center and the overlying cartilage in the background of an ossification disorder.

Molecular events involved in up-regulating human Na+-independent neutral amino acid transporter LAT1 during T-cell activation

We investigated the regulation of system-L amino acid transporter (LAT1) during T-cell activation. In quiescent T-cells, L-leucine transport is mediated mainly by the system-L amino acid transport system and is increased significantly during T-cell activation by PMA and ionomycin. In quiescent T-cells, the LAT1 protein was heterocomplexed with 4F2 heavy chain (4F2hc) in the plasma membrane. During T-cell activation, the amounts of 4F2hc and LAT1 heterocomplex were significantly elevated compared with those in quiescent T-cells. In addition, by Northern-blot analysis, these increments were found to be due to elevated levels of LAT1 and 4F2hc mRNA. Transient expression of constructs comprising various LAT1 gene promoter fragments, which contained all three of the GC boxes, was sufficient for promoting luciferase expression in Jurkat T-cells, but the promoter of the LAT1 gene did not respond to PMA and ionomycin. Similar observations were observed in the human 4F2hc gene promoter. In nuclear run-on assay, the LAT1 and 4F2hc genes were actively transcribed even in quiescent T-cells, but the low levels of both transcripts were shown to be the result of a block to transcription elongation within the exon 1 intron 1 regions. These findings indicated that a removal of the block to mRNA elongation stimulates the induction of system-L amino acid transporter gene transcripts (LAT1 and 4F2hc) in activated T-cells.

Bone tunnel enlargement after anterior cruciate ligament reconstruction using hamstring tendons

We retrospectively reviewed 87 anterior cruciate ligament reconstructions using autogenous hamstring tendons with the Endobutton technique to investigate the relationship between bone tunnel enlargement and clinical outcome and to identify factors that contribute to the enlargement. The clinical outcome was evaluated using the Lysholm score and KT-1000 arthrometer. The location of the femoral tunnel with respect to Blumensaat's line, the tibial tunnel with respect to the tibial plateau, and the angle between the femoral tunnel and Blumensaat's line (femoral tunnel angle) were measured. Bone tunnel enlargement was observed in 32 patients (37%). Enlargement occurred in 22 of the femoral tunnels and 26 of the tibial tunnels. Enlargement of both tunnels occurred in 16 knees. There was no statistical difference in Lysholm scores or KT-1000 arthrometer measurements between the enlarged group and the unenlarged group. The femoral tunnel was placed more anteriorly in the enlarged femoral tunnel group than in the unenlarged femoral tunnel group. The tibial tunnel was placed more anteriorly in the enlarged tibial tunnel group than in the unenlarged tibial tunnel group. The femoral tunnel angle was significantly smaller in the enlarged femoral tunnel group than in the femoral unenlarged group. Gender, patient age, intraoperative isometricity, and graft size were not significant factors. Bone tunnel enlargement was not correlated with the clinical outcome measures. We conclude that the main factor associated with tunnel enlargement are the locations and angles of the tunnels. The windshield-wiper motion of the graft may be enhanced by changing tension in the graft due to tunnel malposition. An acute femoral tunnel angle may increase the mechanical stress on the anterior margin of the femoral tunnel.

Functional repression of Islet-2 by disruption of complex with Ldb impairs peripheral axonal outgrowth in embryonic zebrafish

Islet-2 is a LIM/homeodomain-type transcription factor of the Islet-1 family expressed in embryonic zebrafish. Two Islet-2 molecules bind to the LIM domain binding protein (Ldb) dimers. Overexpression of the LIM domains of Islet-2 or the LIM-interacting domain of Ldb proteins prevented binding of Islet-2 to Ldb proteins in vitro and caused similar in vivo defects in positioning, peripheral axonal outgrowth, and neurotransmitter expression by the Islet-2-positive primary sensory and motor neurons as the defects induced by injection of Islet-2-specific antisense morpholino oligonucleotide. These and other experiments, i.e., mosaic analysis, coexpression of full-length Islet-2, and overexpression of the chimeric LIM domains derived from two different Islet-1 family members, demonstrated that Islet-2 regulates neuronal differentiation by forming a complex with Ldb dimers and possibly with some other Islet-2-specific cofactors.

Identification and functional analysis of three isoforms for the Na+-dependent phosphate co-transporter (NaPi-2) in rat kidney

We have isolated three unique NaPi-2-related protein cDNAs (NaPi-2alpha, NaPi-2beta and NaPi-2gamma) from a rat kidney library. NaPi-2alpha cDNA encodes 337 amino acids which have high homology to the N-terminal half of NaPi-2 containing three transmembrane domains. NaPi-2beta encodes 327 amino acids which are identical to the N-terminal region of NaPi-2 containing four transmembrane domains, whereas the 146 amino acids in the C-terminal region are completely different. In contrast, NaPi-2gamma encodes 268 amino acids which are identical to the C-terminal half of NaPi-2. An analysis of phage and cosmid clones indicated that the three related proteins were produced by alternative splicing in the NaPi-2 gene. In a rabbit reticulocyte lysate system, NaPi-2alpha, beta and gamma were found to be 36, 36 and 29 kDa polypeptides, respectively. NaPi-2alpha and NaPi-2gamma were glycosylated and revealed to be 45 and 35 kDa proteins, respectively. A functional analysis demonstrated that NaPi-2gamma and alpha markedly inhibited NaPi-2 activity in Xenopus oocytes. The results suggest that these short isoforms may function as a dominant-negative inhibitor of the full-length transporter.

Long-term results of non-operative treatment of anterior cruciate ligament injury

We retrospectively reviewed the record of 89 patients with complete anterior cruciate ligament injury, documented by arthroscopic examination to investigate the long-term results in relation to the generation of osteoarthritis. The mean age of the patients was 34.9 years at follow-up and the mean duration of follow-up was 12.0 years. The mean Lysholm score was 89 points at follow-up. The mean Tegner activity score was 5.7 points before injury and 4.5 points at follow-up. Plain radiographs revealed 63% of osteoarthritis and 37% of which had joint space narrowing. The age of the patients, the level of sports activity, the history of meniscectomy, obesity and the osteoarthritis of the contralateral knee were found to be significant risk factors in osteoarthritis after anterior cruciate ligament injury. The most influential factor for osteoarthritis was considered meniscectomy, in combination with the risk factors of primary osteoarthritis. It should also be noted that modification of sports activity level was the most important factor for avoiding the combined injury of meniscus and osteoarthritis.

Radiosurgery of meningeal melanocytoma

The authors present a case of meningeal melanocytoma arising from Meckel's cave. A coal-black, vascular tumor was partially removed by surgery. Histopathologically, the tumor lacked anaplastic features. Immunohistochemical studies confirmed that the tumor was of neuroectodermal origin and had low proliferating activity. The patient underwent gamma knife radiosurgery for the residual tumor, in which 25 Gy of radiation was delivered to the tumor margin. Three years after irradiation, the tumor showed marked shrinkage without complication.

Secondary hyperparathyroidism and phosphate sensing in parathyroid glands

Retention of inorganic phosphate (Pi) and associated hyperphosphatemia are important development of hyperparathyroidism secondary to renal failure. The beneficial effect of a low-Pi diet in the prevention of hyperparathyroidism can be attributed to the decrease in PTH secretion. This effect of Pi may be mediated by specific molecules in the parathyroid cell membrane. A complementary DNA encoding a Na(+)-Pi co-transporter, termed rat PiT-1, has been isolated from rat parathyroid. The amount of PiT-1 mRNA in the parathyroid is controlled by vitamin D and dietary Pi, which are the most important regulators of PTH secretion. The parathyroid Pi transporter may mediate the effects of extracellular Pi and PTH secretion in secondary hyperparathyroidism. In this study, we focus on the function of Na/Pi co-transporters in the parathyroid glands as inorganic Pi sensor.

Transport properties of a system y+L neutral and basic amino acid transporter. Insights into the mechanisms of substrate recognition

The properties of system y(+)L-mediated transport were investigated on rat system y(+)L transporter, ry(+)LAT1, coexpressed with the heavy chain of cell surface antigen 4F2 in Xenopus oocytes. ry(+)LAT1-mediated transport of basic amino acids was Na(+)-independent, whereas that of neutral amino acids, although not completely, was dependent on Na(+), as is typical of system y(+)L-mediated transport. In the absence of Na(+), lowering of pH increased leucine transport, without affecting lysine transport. Therefore, it is proposed that H(+), besides Na(+) and Li(+), is capable of supporting neutral amino acid transport. Na(+) and H(+) augmented leucine transport by decreasing the apparent K(m) values, without affecting the V(max) values. We demonstrate that although ry(+)LAT1-mediated transport of [(14)C]l-leucine was accompanied by the cotransport of (22)Na(+), that of [(14)C]l-lysine was not. The Na(+) to leucine coupling ratio was determined to be 1:1 in the presence of high concentrations of Na(+). ry(+)LAT1-mediated leucine transport, but not lysine transport, induced intracellular acidification in Chinese hamster ovary cells coexpressing ry(+)LAT1 and 4F2 heavy chain in the absence of Na(+), but not in the presence of physiological concentrations of Na(+), indicating that cotransport of H(+) with leucine occurred in the absence of Na(+). Therefore, for the substrate recognition by ry(+)LAT1, the positive charge on basic amino acid side chains or that conferred by inorganic monovalent cations such as Na(+) and H(+), which are cotransported with neutral amino acids, is presumed to be required. We further demonstrate that ry(+)LAT1, due to its peculiar cation dependence, mediates a heteroexchange, wherein the influx of substrate amino acids is accompanied by the efflux of basic amino acids.

Functional analysis of the individual oligosaccharide chains of sendai virus fusion protein

The roles of N-linked glycosylation in the intracellular transport and fusion activity of the Sendai virus fusion (F) protein were studied. Each of three potential glycosylation motifs (designated g1, g2, and g3) in the F protein was mutated separately or in combination with the other sites. When the mutant F proteins were transiently expressed in COS cells, they showed significant changes in electrophoretic mobility, indicating that all three motifs in the F protein are glycosylated. Glycosylation-defective mutants which lacked the g2-oligosaccharide chain showed decreased immunoreactivity with a monoclonal antibody specific for the native conformation and were inefficiently transported to the cell surface. Such mutants, with the exception of a double mutant lacking g1 and g2-oligosaccharide chains, were also not able to induce syncytia formation when cells expressing them plus the hemagglutinin-neuraminidase protein were treated with trypsin. Mutations at the other glycosylation sites did not significantly affect the immunoreactivity with the monoclonal antibody or the efficiency of intracellular transport of the F protein. These results indicate that the N-linked oligosaccharide chain attached at g2 is important for efficient intracellular transport and for the fusion activity of the F protein.

Neurovascular decompression for idiopathic tarsal tunnel syndrome: technical note

OBJECTIVE

The surgical outcome of idiopathic tarsal tunnel syndrome (TTS) is reported to be worse than that attributable to ganglion, tarsal coalition, or tumour, and therefore further development in the surgical treatment for idiopathic TTS is considered to be necessary. Here the efficacy of neurovascular decompression for patients with idiopathic TTS is evaluated.

METHODS

Twelve feet from nine patients with idiopathic TTS were treated. The patients were aged 52-78 years (mean 64.6 years), and all of them complained of pain or dysaesthesia of the sole of the foot. The posterior tibial nerve was freed from the attached arteriovenous complex (posterior tibial artery and veins). The dissected nerve had a flattened appearance in all of the patients, suggesting nerve compression by the adjacent arteriovenous complex and superficially by the flexor retinaculum. A graft of fat was inserted as both a cushion and an antiadhesive between the vessels and the nerve to achieve neurovascular decompression.

RESULTS

Patients on whom neurovascular decompression was performed had resolution or lessening of symptoms in their feet. Neither wound infection nor recurrence of symptoms was found during the follow up period (mean 26.8 months).

CONCLUSION

Neurovascular compression syndrome plays a part in idiopathic TTS, and adding neurovascular decompression to resection of the flexor retinaculum is effective.

[Intraoperative autologous blood transfusion was effective in a massive blood loss during living-related donor liver transplantation]

We have experienced massive blood loss (> 80,000 g) during living-related donor liver transplantation (LRDLT) of a 14-year old girl with biliary atresia. As available homologous blood was not sufficient, we transfused autologous blood (13,400 ml) during operation. Although immunosuppressant was administered to the patient, severe infection did not occur for 10 days after the operation. Cold ischemia time of the graft liver was about 16 hr, but her postoperative liver function was well-maintained. The case suggests that intraoperative autologus blood transfusion is effective if homologous blood is insufficient during LRDLT.

Estimation of the lethal toluene concentration from the accidental death of painting workers

To determine the potentially lethal level of thinner concentration in the air, we measured the concentration of toluene in the blood and others of three patients who suffered severe acute thinner intoxication between 4 January 1996 and 21 April 1997 in Ube city. The concentration of toluene in blood were 30.2 mg/L in died patient, and 13.7 mg/L and 17.5 mg/L in recovered patients, respectively. By extrapolation from the results of our previous toxicokinetic research on toluene poisoning in anesthetized dogs, the fatal concentration of toluene was estimated to be approximately 1800 to 2000 ppm for 1-hour exposure.

Boomerang deformity of cervical spinal cord migrating between split laminae after laminoplasty

Patients with cervical compression myelopathy were studied to elucidate the mechanism underlying boomerang deformity, which results from the migration of the cervical spinal cord between split laminae after laminoplasty with median splitting of the spinous processes (boomerang sign). Thirty-nine cases, comprising 25 patients with cervical spondylotic myelopathy, 8 patients with ossification of the posterior longitudinal ligament, and 6 patients with cervical disc herniation with developmental canal stenosis, were examined. The clinical and radiological findings were retrospectively compared between patients with (B group, 8 cases) and without (C group, 31 cases) boomerang sign. Moderate increase of the grade of this deformity resulted in no clinical recovery, although there was no difference in clinical recovery between the two groups. Most boomerang signs developed at the C4/5 and/or C5/6 level, where maximal posterior movement of the spinal cord was achieved. Widths between lateral hinges and between split laminae in the B group were smaller than in the C group. Flatness of the spinal cord in the B group was more severe than in the C group. In conclusion, the boomerang sign was caused by posterior movement of the spinal cord, narrower enlargement of the spinal canal and flatness of the spinal cord.

Clinicopathological study of intracranial fusiform and dolichoectatic aneurysms : insight on the mechanism of growth

BACKGROUND AND PURPOSE

Intracranial fusiform aneurysms can be divided into 2 clinically different subtypes: acute dissecting aneurysms and chronic fusiform or dolichoectatic aneurysms. Of these 2, the natural history and growth mechanism of chronic fusiform aneurysms remains unknown.

METHODS

A consecutive series of 16 patients with chronic fusiform aneurysms was studied retrospectively to clarify patient clinical and neuroradiological features. Aneurysm tissues were obtained from 8 cases and were examined to identify histological features that could correspond to the radiological findings.

RESULTS

Four histological features were found: (1) fragmentation of internal elastic lamina (IEL), (2) neoangiogenesis within the thickened intima, (3) intramural hemorrhage (IMH) and thrombus formation, and (4) repetitive intramural hemorrhages from the newly formed vessels within thrombus. IEL fragmentation was found in all cases, which suggests that this change may be one of the earliest processes of aneurysm formation. MRI or CT detected IMH, and marked contrast enhancement of the inside of the aneurysm wall (CEI) on MRI corresponded well with intimal thickening. Eight of 9 symptomatic cases but none of 7 asymptomatic cases presented with both radiological features.

CONCLUSIONS

Data suggest that chronic fusiform aneurysms are progressive lesions that start with IEL fragmentation. Formation of IMH seems to be a critical event necessary for lesions to become symptomatic and progress, and this can be monitored on MRI. Knowledge of this possible mechanism of progression and corresponding MRI characteristics could help determine timing of surgical intervention.

Identification and characterization of a Na(+)-independent neutral amino acid transporter that associates with the 4F2 heavy chain and exhibits substrate selectivity for small neutral D- and L-amino acids

A cDNA was isolated from the mouse brain that encodes a novel Na(+)-independent neutral amino acid transporter. The encoded protein, designated as Asc-1 (asc-type amino acid transporter 1), was found to be structurally related to recently identified mammalian amino acid transporters for the transport systems L, y(+)L, x(C)(-), and b(0,+), which are linked, via a disulfide bond, to the type II membrane glycoproteins, 4F2 heavy chain (4F2hc), or rBAT (related to b(0,+) amino acid transporter). Asc-1 required 4F2hc for its functional expression. In Western blot analysis in the nonreducing condition, a 118-kDa band, which seems to correspond to the heterodimeric complex of Asc-1 and 4F2hc, was detected in the mouse brain. The band shifted to 33 kDa in the reducing condition, confirming that Asc-1 and 4F2hc are linked via a disulfide bond. Asc-1-mediated transport was not dependent on the presence of Na(+) or Cl(-). Although Asc-1 showed a high sequence homology (66% identity at the amino acid level) to the Na(+)-independent broad scope neutral amino acid transporter LAT2 (Segawa, H., Fukasawa, Y., Miyamoto, K., Takeda, E., Endou, H., and Kanai, Y. (1999) J. Biol. Chem. 274, 19745-19751), Asc-1 also exhibited distinctive substrate selectivity and transport properties. Asc-1 preferred small neutral amino acids such as Gly, L-Ala, L-Ser, L-Thr, and L-Cys, and alpha-aminoisobutyric acid as substrates. Asc-1 also transported D-isomers of the small neutral amino acids, in particular D-Ser, a putative endogenous modulator of N-methyl-D-aspartate-type glutamate receptors, with high affinity. Asc-1 operated preferentially, although not exclusively, in an exchange mode. Asc-1 mRNA was detected in the brain, lung, small intestine, and placenta. The functional properties of Asc-1 seem to be consistent with those of a transporter subserving the Na(+)-independent small neutral amino acid transport system asc.