Usefulness of galvanic skin reflex monitor in CT-guided thoracic sympathetic blockade for palmar hyperhidrosis

Computed tomography (CT)-guided thoracic sympathetic blockade with ethanol was performed while monitoring sympathetic nerve activity, with an alternating current (AC) galvanic skin reflex (GSR) monitor, in a patient with palmar hyperhidrosis in whom endoscopic thoracic sympathectomy was impossible because of pleural adhesion. Sweating was suppressed after the thoracic sympathetic blockade, and the monitor showed a significant increase in skin resistance. The effect of sympathetic blockade could be evaluated directly and in real time using a GSR monitor.

[Molecular mechanism of ischemic brain injuries and perspectives of drug therapies for neuroprotection]

Ischemic brain injury is a critical condition in the management of patients during anesthesia and intensive care. It is not rare that pathological conditions such as cerebral ischemia, head trauma and low oxygen result in marked impairment of cerebral function, even if the patient's life is saved. We sometimes encounter sudden changes in a patient's condition not only during anesthesia, but also in intensive care unit with transient low-oxygen and ischemic conditions accompanying serious shock. We have been studying the mechanisms to counteract pathological conditions leading to neuronal cell death that have been exposed to such emergency conditions, and to discover therapeutic methods to minimize the brain damage after insult. With advances in the understanding of the mechanism of neuronal cell death, technology in intensive care for salvaging neuronal cell that are at the brink of death and for recovery of brain function has progressed. However, a breakthrough has not been achieved in the development of effective therapy. Protection of the brain from terminal impairment and preservation of function will be an important issue. To achieve this goal, it is critical to clarify the susceptible mechanisms causing ischemic brain damage. This report discusses the importance of the calcineurin/immunophilin signal transduction mechanism as a new mechanism that is involved in the induction of ischemic brain damage and refers the status-quo of cerebral protection by drug therapy.

Re-evaluation of mitochondrial permeability transition as a primary neuroprotective target of minocycline

Minocycline has been shown to be neuroprotective in ischemic and neurodegenerative disease models and could potentially be relevant for clinical use. We revisited the hypothesis that minocycline acts through direct inhibition of calcium-induced mitochondrial permeability transition (mPT) resulting in reduced release of cytochrome c (cyt c). Minocycline, at high dosage, was found to prevent calcium-induced mitochondrial swelling under energized conditions similarly to the mPT inhibitor cyclosporin A (CsA) in rodent mitochondria derived from the CNS. In contrast to CsA, minocycline dose-dependently reduced mitochondrial calcium retention capacity (CRC) and respiratory control ratios and was ineffective in the de-energized mPT assay. Further, minocycline did not inhibit calcium- or tBid-induced cyt c release. We conclude that the neuroprotective mechanism of minocycline is likely not related to direct inhibition of mPT and propose that the mitochondrial effects of minocycline may contribute to toxicity rather than tissue protection at high dosing in animals and humans.

[Evaluation of cancer pain--possibility of biomarkers]

The accurate assessment of pain is needed to control cancer pain and its treatment. Pain itself is subjective experience and is difficult to estimate quantitatively. Until now, there is no precise method to quantitate the cancer pain objectively. First, we show the tools to assess cancer pain by patient's description, including visual analogue scales, verval rating scales and numerical rating scales and so on. These scales have been used to evaluate the intensity of clinical pain, however they cannot assess the quality of cancer pain and only McGill Pain Questionnaire (MPQ) has specificity for the qualitative and quantitative properties of clinical pain. Molecular biological approach has been advanced in the neuroscience field to find the candidate of neuropathic pain. In this article, we would like to show the results of the proteomics research for neuropathic pain. We also tried to discuss about the biomarker and its possibility whether it can reflect cancer pain and effect of cancer treatment.

[General anesthesia for thyroplasty employing voice test]

BACKGROUND

We reported an anesthetic technique for thyroplasty employing voice test. Thyroplasty is performed to improve voice quality in patients with unilateral vocal cord paralysis. Correct displacement of the vocal cord is assessed by asking the patient to phonate. At this point all patients should have recovered from general anesthesia and cooperate to phonation, facilitating correct displacement of the vocal cords.

METHODS

Anesthesia was induced with i.v. pentazocine 15-30 mg and continuous propofol infusion 10 mg x kg(-1) x hr(-1). The patients received propofol infusion 4-6 mg x kg(-1) x hr(-1) with spontaneous ventilation. At the point of correct displacement of the vocal cords, we stopped propofol infusion and all the patients woke up immediately and cooperated. After determining the voice propofol was given at a rate of 4-6 mg x kg(-1) x hr(-1).

RESULTS

The average times of surgery and anesthesia were 98 +/- 23 min and 139 +/- 22 min, respectively. At the point of correct displacement of the vocal cords, the average time from the end of propofol infusion until awakening with good quality of recovery was 313 +/- 93 sec. No patients complained of pain during or after

CONCLUSIONS

This anesthetic technique provided both optimal operating conditions and patient comfort without serious complications.

Effects of temperature gradient correction of carbon dioxide absorbent on carbon dioxide absorption †

BACKGROUND

The effects of temperature gradients in CO(2) absorbents on water content and CO(2) absorption are not clear. We constructed a novel temperature gradient correction (TGC) canister, and investigated the effects of temperature gradient correction on the water content and longevity (time to exhaustion) of CO(2) absorbent using a simulated anaesthesia circuit.

METHODS

Experiments were divided into two groups according to the type of canister used: the TGC canister (n=6) or the conventional canister (n=6). One kilogram of fresh CO(2) absorbent was placed into the canister. The anaesthetic ventilator was connected to a 3 litre bag and 300 ml min(-1) of CO(2) was introduced. Oxygen (500 ml min(-1)) was used as fresh gas. The anaesthetic ventilator was set at a ventilatory frequency of 12 bpm, and tidal volume was adjusted to 700 ml.

RESULTS

Before the experiment, the water content of the fresh CO(2) absorbent in the conventional canister and TGC canister was 16.1 (0.9)% and 15.7 (1.1)%, respectively. After the experiment, the water content of CO(2) absorbent near the upper outer rim of the canister increased to 32.4 (0.7)% in the conventional canister, but increased to only 20.6 (1.3)% in the TGC canister (P<0.01). The longevity of CO(2) absorbent in the conventional canister and TGC canister was 434 (9) min and 563 (13) min (P<0.01).

CONCLUSIONS

Temperature gradient correction prevented a local excessive increase in water content and improved the longevity of CO(2) absorbent.

NK105, a paclitaxel-incorporating micellar nanoparticle, is a more potent radiosensitising agent compared to free paclitaxel

NK105 is a micellar nanoparticle formulation designed to enhance the delivery of paclitaxel (PTX) to solid tumours. It has been reported to exert antitumour activity in vivo and to have reduced neurotoxicity as compared to that of free PTX. The purpose of this study was to investigate the radiosensitising effect of NK105 in comparison with that of PTX. Lewis lung carcinoma (LLC)-bearing mice were administered a single intravenous (i.v.) injection of PTX or NK105; 24 h after the drug administration, a proportion of the mice received radiation to the tumour site or lung fields. Then, the antitumour activity and lung toxicity were evaluated. In one subset of mice, the tumours were excised and specimens were prepared for analysis of the cell cycle distribution by flow cytometry. Combined NK105 treatment with radiation yielded significant superior antitumour activity as compared to combined PTX treatment with radiation (P=0.0277). On the other hand, a histopathological study of lung sections revealed no significant difference in histopathological changes between mice treated with PTX and radiation and those treated with NK105 and radiation. Flow-cytometric analysis showed that NK105-treated LLC tumour cells showed more severe arrest at the G2/M phase as compared to PTX-treated tumour cells. The superior radiosensitising activity of NK105 was thus considered to be attributable to the more severe cell cycle arrest at the G2/M phase induced by NK105 as compared to that induced by free PTX. The present study results suggest that further clinical trials are warranted to determine the efficacy and feasibility of combined NK105 therapy with radiation.

A novel neuroprotective compound FR901459 with dual inhibition of calcineurin and cyclophilins

Brain ischemia leads to severe damage in the form of delayed neuronal cell death. In our study, we show that the marked neuroprotection of the new immunosuppressant FR901495 in forebrain ischemia is due not only to inhibition of calcineurin, but also to protection against mitochondrial damage caused by mitochondrial permeability transition pore formation through cyclophilin D, one of the prolyl cis/trans isomerase family members. These findings shed light on the clinical application and development of new drugs for the treatment of ischemic damage in the brain as well as in the heart and liver.

Search for novel gene markers of traumatic brain injury by time differential microarray analysis

Neuronal and glial cell death caused by axonal injury sometimes contributes to whole brain pathology after traumatic brain injury (TBI). We show that neuroprotection by 2 types of immunosuppressants, cyclosporin A (CsA) and tacrolimus (FK506), in a cryogenic brain injury model results from inhibition of calcineurin and protection from mitochondrial damage caused by formation of a mitochondrial permeability transition pore induced by cyclophilin D (CyPD), one of the prolyl cis/trans isomerase family members. We evaluated why CsA is neuroprotective by microarray analysis of gene expression in the cryogenic brain injury rat model. Analyses of expression patterns demonstrated that expression of over 14,000 genes changed between the groups with and without CsA treatment, and about 350 genes among them were extracted showing a significant difference. We learned that the differential expression of several gene targets showed specific patterns in a time-dependent manner. These results may help elucidate the mechanisms of neuronal cell death after TBI and the neuroprotective effects of CsA after TBI.

Effect of Cyclosporin A on Immediate Early Gene in Rat Global Ischemia and Its Neuroprotection

The expressions of the immediate early genes, c-fos and c-jun, and their product proteins C-FOS, C-JUN, and P-JUN were examined in the hippocampal CA1 subfield after global ischemia and reperfusion in rats treated with cyclosporin A. More than 90% neuronal cell death was seen in hippocampal CA1 7 days after global ischemia in control animals, but only 5% cell death after ischemia was seen in the CsA-treated animals. The expressions of c-fos and c-jun mRNA in the control animals were detected with an increase from 1 to 48 h after ischemia. On the other hand, they showed significant suppression in the CsA-treated animals. Increased expressions of C-FOS were found 1, 24, and 48 h after reperfusion in the control animals. In the CsA-treated animals C-FOS expression was found to increase, but the expression level reduced to a statistically insignificant level within 48 h after the ischemia. C-JUN and P-JUN expressions increased in control animals, but were almost completely suppressed in the CsA-treated animals. The present study demonstrated that the suppressant effects of CsA on IEGs and their products might have causal relationship to the dramatic protecting effect of the drug against delayed neuronal cell death.

Cisplatin-incorporating polymeric micelles (NC-6004) can reduce nephrotoxicity and neurotoxicity of cisplatin in rats

In spite of the clinical usefulness of cisplatin (CDDP), there are many occasions in which it is difficult to continue the administration of CDDP due to its nephrotoxicity and neurotoxicity. We examined the incorporation of CDDP into polymeric micelles to see if this allowed the resolution of these disadvantages. Cisplatin was incorporated into polymeric micelles through the polymer-metal complex formation between polyethylene glycol poly(glutamic acid) block copolymers and CDDP (NC-6004). The pharmacokinetics, pharmacodynamics, and toxicity studies of CDDP and NC-6004 were conducted in rats or mice. The particle size of NC-6004 was approximately 30 nm, with a narrow size distribution. In rats, the area under the curve and total body clearance values for NC-6004 were 65-fold and one-nineteenth the values for CDDP (P<0.001 and 0.01, respectively). In MKN-45-implanted mice, NC-6004 tended to show antitumour activity, which was comparable to or greater than that of CDDP. Histopathological and biochemical studies revealed that NC-6004 significantly inhibited the nephrotoxicity of CDDP. On the other hand, blood biochemistry revealed transient hepatotoxicity on day 7 after the administration of NC-6004. Furthermore, rats given CDDP showed a significant delay (P<0.05) in sensory nerve conduction velocity in their hind paws as compared with rats given NC-6004. Electron microscopy in rats given CDDP indicated the degeneration of the sciatic nerve, but these findings were not seen in rats given NC-6004. These results were presumably attributable to the significantly reduced accumulation of platinum in nerve tissue when NC-6004 was administered (P<0.05). NC-6004 preserved the antitumour activity of CDDP and reduced its nephrotoxicity and neurotoxicity, which would therefore seem to suggest that NC-6004 could allow the long-term administration of CDDP where caution against hepatic dysfunction must be exercised.

[Cerebral aneurysms in identical twins]

The hypothesis that genetic factors play a role in the genesis of cerebral aneurysms may be supported by clinical analysis of cerebral aneurysms in identical twins. In addition to reporting the present case, we review the literature on clinical features and genetical considerations in this matter. A forty-two-year-old male presented with subarachnoid hemorrhage (SAH) due to a left MCA aneurysm. At the age of 39, his identical twin brother also had SAH due to a ruptured left MCA aneurysm. This identical twin brother and his father's sisters died of SAH. Venous blood of the patient and his parents was collected to determine apolipoprotein E, angiotensinogen, angiotensin-converting enzyme, and very low density lipoprotein receptor genes. This analysis suggested a strong genetic association of apolipoprotein E epsilon4 with the pathogenesis. Including our cases, 13 cases of cerebral aneurysms in identical twins have been reported. There was a total of 37 aneurysms. Six twins had the same sites of aneurysm. These aneurysms show a tendency to be small in size, and to cause a high frequency of SAH occurring at a similar age. In young adults, cerebral aneurysms in identical twins tend to rupture. A screening diagnosis should be carried out as early as possible on an asymptomatic twin when the other has been discovered to have a ruptured cerebral aneurysm. Preventive treatment and systemic genome-wide linkage study should be conducted.

[Surgical osteoplasty of the left main coronary artery using the right internal thoracic artery]

A 39-year-old female with a history of progressive refractory angina required medical treatment. A coronary angiography showed 75% left coronary ostial stenosis without any other atherosclerotic lesions. The isolated ostial stenosis of the left main coronary artery was reconstructed by patch angioplasty, using a proximal segment of the right internal thoracic artery. The transaortic patch angioplasty was performed using a superior approach, which allowed a good exposure of the left coronary artery to the aorta without difficulty. A postoperative coronary angiography showed satisfactory patency, and a small biopsy of the ostial tissue demonstrated findings compatible with fibromuscular dysplasia. Based on this outcome, a proximal segment of the internal thoracic artery appears to provide a suitable patch material for enlarging the left coronary ostium.

A Comparison of Frontal and Occipital Bispectral Index Values Obtained During Neurosurgical Procedures

We placed bispectral index (BIS) sensors on the frontal and occipital areas of neurosurgical patients and compared BIS values obtained from both areas during propofol/fentanyl anesthesia. BIS showed a strong correlation between frontal and occipital montages (r(2) = 0.96; P = 0.03). It may be valid to measure BIS with the sensor on the occipital area if required during frontal neurosurgical procedures.

IMPLICATIONS

Bispectral values were positively correlated when recorded from frontal and occipital sensors in patients undergoing clipping of unruptured cerebral aneurysms while anesthetized with propofol and fentanyl.

Little evidence of transdifferentiation of bone marrow-derived cells into pancreatic beta cells

AIMS/HYPOTHESIS

Bone marrow cells contain at least two distinct types of stem cells which are haematopoietic stem cells and mesenchymal stem cells. Both cells have the ability to differentiate into a variety of cell types derived from all three germ layers. Thus, bone marrow stem cells could possibly be used to generate new pancreatic beta cells for the treatment of diabetes. In this study, we investigated the feasibility of bone marrow-derived cells to differentiate into beta cells in pancreas.

METHODS

Using green fluorescent protein transgenic mice as donors, the distribution of haematogenous cells in the pancreas was studied after bone marrow transplantation.

RESULTS

In the pancreas of green fluorescent protein chimeric mice, green fluorescent protein-positive cells were found in the islets, but none of these cells expressed insulin. Previous data has suggested that tissue injury can recruit haematopoietic stem cells or their progeny to a non-haematopietic cell fate. Therefore, low-dose streptozotocin (30 or 50 mg/kg on five consecutive days) was injected into the mice 5 weeks after bone marrow transplantation, but no green fluorescent protein-positive cells expressing insulin were seen in the islets or around the ducts of the pancreas.

CONCLUSIONS/INTERPRETATION

Our data suggests that bone marrow-derived cells are a distinct cell population from islet cells and that transdifferentiation from bone marrow-derived cells to pancreatic beta cells is rarely observed.

Calcineurin and cyclophilin D are differential targets of neuroprotection by immunosuppressants CsA and FK506 in ischemic brain damage

The search for an effective treatment for global ischemia following cardiac arrest has proved to be very difficult. However, studies by Uchino et al. show that the immunosuppressant cyclosporin A (CsA), when administered in such a way that the drug can bypass the blood brain barrier (BBB), dramatically reduces ischemic damage in rat forebrain preparations. An alternative immunosuppressant, FK506, is apparently less efficacious. Both CsA and FK506 are specific inhibitors of immunophilins, (CsA inhibits cyclophilins, FK506 inhibits FKBPs), and of calcineurin, a type 2B Ser/Thr phosphatase that is abundant in the central nervous system. The superiority of CsA may be partly attributable to its selective amelioration of mitochondrial damage, as assayed in vivo and in vitro. Our results suggest that pathways involving calcineurin and cyclophilins, particularly mitochondrial cyclophilin D, play pivotal roles in the development of ischemic brain damage. The present findings may inform the search for new drugs in the treatment of global ischemic damage to the brain, and in other organs.

Differential Neuroprotection by Cyclosporin A and FK506 Following Ischemia Corresponds with Differing Abilities to Inhibit Calcineurin and the Mitochondrial Permeability Transition

Transient global or forebrain ischemia leads to severe brain damage following delayed neuronal cell death. We previously reported that cyclosporin A (CsA) provides near total suppression of brain damage in rat forebrain ischemia when allowed to pass the blood brain barrier, whereas Tacrolimus (FK506) is considerably less effective. We demonstrate herein that when administered prior to ischemic insult, both immunosuppressants equally block calcineurin, a type 2B Ser/Thr phosphatase, and efficiently inhibit dephosphorylation of pro-apoptotic protein Bad. CsA demonstrates more potent anti-ischemic effects than FK506, partially attributable to amelioration of mitochondrial damage as assayed in vivo and in vitro. These results suggest that pathways including calcineurin and cyclophilins, particularly mitochondrial cyclophilin D, play pivotal roles in ischemic brain damage. Since previous results have shown that CsA is efficacious also when administered after focal ischemia, the present findings give hints to clinical applications for new drugs for the treatment of ischemic damage in the brain as well as in the heart and liver.

Calcineurin as a multifunctional regulator

Long recognized as an important regulatory mechanism in biosignal processes, modulation of the phosphorylation state of proteins has emerged as the most important mechanism for understanding signal transduction. In contrast to the multitude of protein kinases and the clear signal transduction pathways, relatively few protein phosphatases are known and their regulation is unclear. Among them, calcineurin, a calcium/calmodulin-dependent phosphatase (PP2B), is the best enzyme to unveil the phosphatase function, because it was shown to be the direct target for immunosuppressants CsA and FK506, which are powerful tools for understanding this function in diseases as well as in several tissues and organs. Although calcineurin has been found in the highest concentrations in brain, it has also been detected in many other mammalian tissues. Well characterized in T cell activation by analysing the transcription factor NFAT, the function of calcineurin, however, was less well understood in other tissues and organs. Since the mid-1990s, several novel functions of this phosphatase have been reported, revealing that it plays important roles as a multifunctional regulator under the direct regulation of calcium signaling.

Involvement of the brain-derived neurotrophic factor/TrkB pathway in neuroprotecive effect of cyclosporin A in forebrain ischemia

Recent studies have shown that cyclosporin A, a specific antagonist of calcineurin, a phosphatase, ameliorates neuronal cell death in the CA1 sector of the hippocampus after forebrain ischemia in animal models. The mechanism of this neuroprotective effect, however, has not yet been established. Brain-derived neurotrophic factor (BDNF), a member of the neurotrophins, is one of the potent survival and developmental factors whose expression is regulated by cyclic AMP-response element-binding protein (CREB). Activation of CREB is dependent on its phosphorylation at Ser(133), and calcineurin has been reported to dephosphorylate CREB via protein phosphatase 1. Based on these observations, we attempted to investigate how cyclosporin A treatment would affect the changes of phosphorylated CREB (pCREB), BDNF and its receptor tyrosine kinase B (TrkB) after forebrain ischemia in rats. Phosphorylation of CREB was kept augmented throughout the time course examined in cyclosporin A-treated animals, while it ceased without cyclosporin A. Reverse transcription-polymerase chain reaction revealed prolonged maintenance of BDNF mRNA expression in the CA1 sector of cyclosporin A-treated animals. The protein expression of BDNF and TrkB appeared to be up-regulated in cyclosporin A-treated animals, whereas it was transiently up-regulated but decreased to the marginal level of expression without cyclosporin A.From these results we suggest that cyclosporin A induces pCREB by an inhibition of calcineurin, resulting in the induction of BDNF. The mechanisms by which cyclosporin A protects the CA1 region from neuronal cell death in forebrain ischemia may involve the interaction of pCREB, BDNF and TrkB.

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.

Cyclosporin A, but not FK506, prevents the downregulation of phosphorylated Akt after transient focal ischemia in the rat

The two immunosuppressants, cyclosporin A (CsA) and FK506, when given 1 and 3 h after the start of reperfusion following 2 h of middle cerebral artery (MCA) occlusion, reduce infarct volume to 30% of control. This suggests a common effect, e.g. one due to suppression of the activation of calcineurin. However, when given by the intracarotid (i.c.) route after only 5 min of recirculation CsA, but not FK506, reduced infarct volume even further, to 10% of control. This was attributed to the fact that CsA, but not FK506, block the in vitro assembly of a mitochondrial permeability transition (MPT) pore. The present experiments were undertaken to further characterize the anti-ischemic effect of CsA, when given i.c. 5 min after recirculation and to explore why CsA, when given at that time, is more efficacious than FK506. It was established that the i.c. administration of CsA in a dose of 10 mg/kg increased the tissue concentration of CsA 2- to 3-fold, when compared to the i.v. administration. CsA proved to be effective in reducing infarct volume even when the tissue damage was assessed by histopathology after 7 days of recovery. MCA occlusion of 2 h duration caused a sustained decrease in the phosphorylation Akt at threonine 308. Since this down regulation of Akt was prevented by CsA, the results suggested a link between dephosphorylaltion of Bad, and cell death. Interestingly FK506 did not prevent down regulation of Akt, it thus seems unlikely that the anti-ischemic effect of CsA is related to its association with cytosolic cyclophilin.

Molecular and functional identification of large neutral amino acid transporters LAT1 and LAT2 and their pharmacological relevance at the blood-brain barrier

We present here the evidence of molecular and functional expression of LAT1 and LAT2, subunits of the large neutral amino acid transporter system L, in cultured brain capillary endothelial cells of the rat. By means of the RT-PCR method, transcripts of LAT1, LAT2 and heavy chain of 4F2 antigen (4F2hc) were detected in rat primary cultured brain capillary endothelial cells (BCECs) and immortalized subline, RBEC1. The uptake properties of RBEC1, such as [3H]leucine and L-[3H]DOPA uptake, were similar to those of primary cultured BCECs. So, RBEC1 may retain almost native properties of the large neutral amino acid uptake activities. [3H]Leucine uptake by RBEC1 showed two saturable components and the Km values of the high- and low-affinity components were 8.92+/-3.18 and 119+/-45 microM, respectively. The Km value of the high-affinity component agreed well with that of LAT1 and the amino acid transport selectivity of RBEC1 was similar to that of LAT1. Therefore, it is suggested that LAT1 is important at the blood-brain barrier of rats. Additionally, the Km value of the low-affinity component was similar to that of LAT2. These observations indicate that LAT1 and LAT2 are involved as transporters for large neutral amino acids at the blood-brain barrier. Additionally, we concluded that RBEC1 is useful as an in-vitro model for evaluation of the pharmacological relevance of system L at the blood-brain barrier.

Clinical usefulness of measuring urinary polyol excretion by gas-chromatography/mass-spectrometry in type 2 diabetes to assess polyol pathway activity

INTRODUCTION

Decreased myo-inositol levels and increased activity of the polyol pathway have been proposed to play a role in causing diabetic microvascular complications. There are few clinical methods for examining the activity of the polyol pathway in diabetic patients. We assessed the effect of changes in glycemic control on polyol pathway activity by measuring urinary polyol excretion.

MATERIALS AND METHODS

Gas-chromatography/mass-spectrometry (GC/MS) was used to assess the urinary excretion of glucose and polyols (myo-inositol, sorbitol, and fructose) in 50 patients who had type 2 diabetes without nephropathy and 20 healthy subjects.

RESULTS

In the diabetic patients with poor glycemic control, urinary sorbitol levels were significantly increased and urinary myo-inositol excretion was approximately 6.5-fold higher than in healthy controls (33.0+/-6.5 vs 221.7+/-45.9 mg/day, mean+/-SE, P<0.01). During strict glycemic control, some patients (Group A) showed simultaneous disappearance of glucosuria and normalization of the urinary excretion of myo-inositol (<50 mg/day) and, while others (Group B) showed delayed normalization of urinary myo-inositol excretion. Group B showed significantly higher urinary myo-inositol, sorbitol, and fructose excretion than Group A at the time of disappearance of glucosuria. These findings suggest that patients in Group B may have increased polyol pathway activity.

CONCLUSION

Even though short-term strict glycemic regulations were established in long-standing hyperglycemic diabetic patients, to normalize the once-exaggerated polyol pathway activities, it was essential to maintain glucosuria-free conditions for some period. Quantitation of urinary polyols using GC/MS appears to be a clinically useful method for assessing polyol pathway activity.

Staphylococcal scalded skin syndrome with prosthetic valve endocarditis

We report staphylococcal scalded skin syndrome (SSSS) in a 67-year-old man. He showed diffuse erythema with erosion on his face and erythema with giant desquamation on his neck, axilla, genitalia, chest and abdomen 39 days after a coronary artery bypass graft and aortic valve replacement. He died of cardiac rupture caused by myocardial necrosis, and autopsy findings demonstrated prosthetic valve endocarditis due to a strain of exfoliative toxin-B producing methicillin-resistant Staphylococcus aureus. To the best of our knowledge, this is the first case of SSSS caused by prosthetic valve endocarditis.