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N Adachi

Publications and source records attributed to N Adachi.

At least 37 records · Page 2Linked to original sources
PubMed2001

Brain-derived neurotrophic factor enhances depolarization-evoked glutamate release in cultured cortical neurons.

Brain-derived neurotrophic factor (BDNF) has been reported to play an important role in neuronal plasticity. In this study, we examined the effect of BDNF on an activity-dependent synaptic function in an acute phase. First, we found that short-term treatment (10 min) with BDNF enhanced depolarization-evoked glutamate release in cultured cortical neurons. The enhancement diminished gradually according to the length of BDNF treatment. The BDNF-enhanced release did not require the synthesis of protein and mRNA. Both tetanus toxin and bafilomycin abolished the depolarization-evoked glutamate release with or without BDNF, indicating that BDNF acted via an exocytotic pathway. Next, we investigated the effect of BDNF on intracellular Ca(2+). BDNF potentiated the increase in intracellular Ca(2+) induced by depolarization. The Ca(2+) was derived from intracellular stores, because thapsigargin completely inhibited the potentiation. Furthermore, both thapsigargin and xestospongin C inhibited the effect of BDNF. These results suggested that the release of Ca(2+) from intracellular stores mediated by the IP(3) receptor was involved in the BDNF-enhanced glutamate release. Last, it was revealed that the enhancement of glutamate release by BDNF was dependent on the TrkB-PLC-gamma pathway. These results clearly demonstrate that short-term treatment with BDNF enhances an exocytotic pathway by potentiating the accumulation of intracellular Ca(2+) through intracellular stores.

Animals↗
PubMed2001

Detection of craniospinal dissemination of intracranial germ cell tumours based on serum and cerebrospinal fluid levels of tumour markers.

Nineteen intracranial germ cell tumours treated during the past 11 years were evaluated retrospectively. The tumours were classified into three groups according to the level of alpha-fetoprotein (AFP) and beta-human chorionic gonadotropin (HCG) in serum and cerebrospinal fluid, and the optimal treatment for each group was determined. Group A consisted of patients with normal titres of AFP and HCG, group B of patients with relatively high titres (< 10 times normal), and group C comprised patients with higher titres ( 10 times normal levels). In group A, an appropriate field and dose of irradiation was necessary to prevent craniospinal dissemination. In group B, none of four patients who underwent total or subtotal resection of the tumour had craniospinal disseminatio n or tumour recurrence, whereas dissemination occurred in four further patients, including two who had received radiochemotherapy only, and two who had undergone partial resection of the tumour. While patients in group C had dissemination at the time of initial diagnosis, most patients in group B developed dissemination more than 10 months after initial treatment, suggesting that the type of treatment received as first line therapy is important in patients in this group. The prognosis of patients in group C, however, was unaffected by the priority given to either surgery, radiation or chemotherapy as first line treatment. Craniospinal dissemination can be prevented in patients with germ cell tumours who have a relative increase in levels of AFP and HCG by aggressive removal of the tumours as first line therapy, regardless of the type of adjuvant therapy given.

Adolescent↗
PubMed2001

Nosocomial rotavirus in a pediatric hospital.

We describe a nosocomial rotavirus outbreak among pediatric cardiology patients and the impact of a prospective, laboratory-based surveillance program for rotavirus in our university-affiliated, quartenary-care pediatric hospital in New York City. Improved compliance with infection control and case-finding among patients and healthcare workers halted the outbreak.

Adolescent↗
PubMed2001

Intraosseous hypertension and venous congestion in osteonecrosis of the knee.

To determine whether an angiogenic factor affects the pathogenesis of the idiopathic osteonecrosis of the medial femoral condyle, intraosseous pressure and venogram in 11 knees with osteonecrosis were compared with intraosseous pressure and venogram in 11 knees with the medial type of osteoarthritis. Patients were matched by age, gender, obesity index, blood pressure, tibiofemoral angle, and clinical evaluation. The intraosseous pressure of the medial condyle of the knees with osteonecrosis (62.8 +/- 27.3 mm Hg) was significantly higher than that in the lateral condyle of the knees with osteonecrosis (25.4 +/- 18.9 mm Hg) and those of both condyles of the knees with osteoarthritis (medial, 31.6 +/- 17.4 mm Hg; lateral, 29.5 +/- 11.0 mm Hg). In contrast, there was no significant difference in the pressure between the medial and lateral condyles of the knees with osteoarthritis. Venography showed a marked disturbance of venous drainage in all patients with osteonecrosis. In addition, the average clearance time of the medium in the medial femoral condyle was significantly more prolonged in patients with osteonecrosis (17.7 +/- 6.1 minutes) than in patients with osteoarthritis (5.5 +/- 1.6 minutes). These data support the hypothesis that venous stasis within the medullar canal in the condyle increases intraosseous pressure and decreases arteriovenous pressure difference, leading to osteonecrosis.

Aged↗
PubMed2001

Blockade of central histaminergic H2 receptors aggravates ischemic neuronal damage in gerbil hippocampus.

OBJECTIVE: Histaminergic H2 antagonists have been reported to provoke central nervous system dysfunction in humans. They also aggravate ischemic neuronal damage in experimental animals. Because energy failure and glutamate release are crucial factors in ischemic neuronal damage, the effects of ranitidine on energy state and the extracellular concentration of glutamate were investigated in gerbil brain. DESIGN: Prospective, randomized, controlled animal study. SETTING: University animal laboratory. SUBJECTS: Male Mongolian gerbils. INTERVENTIONS: The changes in the direct-current potential shift in the hippocampal CA1 area produced by transient forebrain ischemia for 2.5 mins were compared in gerbils pretreated with saline or ranitidine (10 nmol) intracerebroventricularly. The histologic outcome was evaluated 7 days after ischemia by observing the delayed neuronal death in these animals. In a second study, brain concentrations of adenosine 5'-triphosphate after various durations of decapitation ischemia were determined, and the effect of ranitidine was evaluated. In a third experiment, changes in the extracellular concentrations of excitatory amino acids during forebrain ischemia were examined by a microdialysis procedure. MEASUREMENTS AND MAIN RESULTS: The forebrain ischemia produced a sudden shift in the membrane potential 62 +/- 5 secs (mean +/- sd, n = 6) after the start of ischemia. The preischemic administration of ranitidine facilitated onset of depolarization (38 +/- 8 secs; p <.01). The histologic outcome was aggravated by ranitidine (p <.01). Decapitation ischemia reduced brain adenosine 5'-triphosphate concentration rapidly. Ranitidine facilitated the ischemic reduction in adenosine 5'-triphosphate, and the value after 1 min was 55% of that in the corresponding saline group (p <.01). Ranitidine enhanced the ischemic increase in the glutamate concentration, and the peak value in the ranitidine group was 316% of that in the saline group (p <.05). CONCLUSION: The deleterious effect of ranitidine on ischemic neuronal damage may involve the increase in the extracellular concentration of glutamate and facilitation of energy depletion in an anaerobic state.

Adenine Nucleotides↗
PubMed2001

New pain following cordotomy: clinical features, mechanisms, and clinical importance.

OBJECT: The clinical features, possible causes, and contributing factors associated with novel spontaneous pain following unilateral cordotomy were investigated to clarify the mechanism and clinical importance of this pain. METHODS: Forty-five patients who underwent cordotomy for severe unilateral cancer pain were included in this study. New pain occurred in 33 (73.3%) of 45 patients. Pathological conditions of tissue demonstrated on imaging corresponded to new pain in eight patients, referred pain in five, and neither of these in 15 patients. New pain was centered opposite the site of the original pain in a mirror-image location in 28 patients and rostral to the original pain in five patients. It was temporary in seven patients, weaker than the original pain in 25, and as severe as the original pain in one patient. The incidence of moderate or severe pain was significantly higher in patients with confirmed tissue disease (six of eight patients) than in those without (six of 20 patients). An important contributing factor to the occurrence of new pain was the achievement of analgesia by performing the cordotomy. CONCLUSIONS: The present results indicate that new pain occurs frequently after unilateral cordotomy. Nonetheless, cordotomy may still be indicated for unilateral uncontrollable pain because new pain, when present, was weaker and more easily controlled than the original pain in nearly all cases. The authors speculate that new pain may represent a type of referred pain from the original painful area or may arise from sensitization of contralateral spinal nociceptive circuits due to metastasis or tumor infiltration, and that new pain is potentiated by the interruption of descending inhibitory pathways.

Adult↗
PubMed2001

[Evaluation of efficiency of ACD-CPR and STD-CPR; a multi-institutional study].

We compared the efficacy of ACD-CPR and STD-CPR based on 64 multi-institutional reports. No significant differences were observed in the rate of restoration of spontaneous circulation (ROSC) and in cardiopulmonary parameters during CPR using the two methods. There were 5 cases in which cardiopulmonary parameters improved after switching from STD-CPR to ACD-CPR and, eventually, in two of them spontaneous circulation was restored. In the ROSC cases of both groups, ETCO2 and values of SpO2, PaO2, and systolic BP at 30 minutes were higher than those of non-ROSC cases. ETCO2 never exceeded 20 mmHg in the non-ROSC cases, but it was higher in the ROSC cases. ACD-CPR is a good choice when trained persons are present or when extra hands are available to continue the CPR.

Adolescent↗
PubMed2001

Muscle-based gene therapy and tissue engineering.

The development of new biological approaches based on cell and gene therapies, in combination with tissue engineering, may create innovative ways to treat various tissues of the musculoskeletal system. It is vital for practicing orthopaedic surgeons to understand the terminology, fundamental concepts, and current research in this burgeoning field so that they may practice their discipline in its fullest form. Such techniques, coupled with advances in cell biology and polymer chemistry, are resulting in novel approaches to treating musculoskeletal disorders in which surgeons, who have traditionally used the tools of excision and reconstruction to treat patients, may now serve as surgical gardeners who create microenvironments that are conducive for tissue regeneration. Gene therapy and tissue engineering applications for bone healing, articular disorders, and skeletal muscle diseases and injuries are currently being explored. This review is intended to update readers on the principles and current advances in muscle-based gene therapy and tissue engineering for the musculoskeletal system.

Animals↗
PubMed2000

Predictive variables of interictal psychosis in epilepsy.

OBJECTIVE: To evaluate which variables predict interictal psychosis in epilepsy. METHODS: The authors reviewed the biological backgrounds, clinical characteristics, and EEG findings in 246 patients with epilepsy and interictal psychosis and in 658 control patients with epilepsy and no psychotic history. With a logistic regression approach, the significance of each variable for the development of interictal psychosis was evaluated. RESULTS: There are significant differences in family history of psychosis, age at onset of epilepsy, type of epilepsy, lateralization of epileptiform discharges, and level of intelligence between patients with interictal psychosis and those without it. Subsequent logistic regression analysis with all variables demonstrated that family history of psychosis, age at onset of epilepsy, type of seizures, and level of intelligence significantly correlated with psychosis. CONCLUSIONS: A family history of psychosis, earlier age at onset of epilepsy, complex partial seizures or generalized tonic clonic seizures, and borderline intellectual functioning were the most important predictors for development of interictal psychosis.

Adolescent↗
PubMed2000

Different roles of neuronal and endothelial nitric oxide synthases on ischemic nitric oxide production in gerbil striatum.

The production of nitric oxide (NO) in gerbil striatum during ischemia and reperfusion was monitored by measuring total NO metabolites in dialysates, and the effects of 7-nitroindazole (7-NI), a selective inhibitor of neuronal NO synthase, and N(G)-nitro-L-arginine methyl ester (L-NAME), a non-selective inhibitor of NO synthase, were examined. The effects of these agents on ischemic neuronal damage were histologically evaluated 7 days after transient ischemia for 5 or 10 min. 7-NI and L-NAME decreased the NO production to similar extents in non-ischemic gerbils. 7-NI inhibited the increased NO production after 5 min of ischemia, and partly attenuated the increase in NO production after 10 min of ischemia, but had no effect on the increase after 15 min of ischemia. L-NAME completely abolished the increased NO production after different durations of ischemia. The extent of ischemic neuronal damage by 5-min ischemia was aggravated by either 7-NI or L-NAME, while damage by 10-min ischemia was marked in all groups. These results indicate that neuronal and endothelial NO synthases make different contributions to the post-ischemic NO production and the histological outcomes in gerbil striatum.

Animals↗
PubMed2000

Isomerization reaction of olefin using RuClH(CO)(PPh(3))(3)

When methyl 5-(tert-butyldiphenylsilyl)oxy-2-pentenoate was refluxed in toluene in the presence of RuClH(CO)(PPh(3))(3) (5 mol %), double-bond migration took place to afford methyl 5-(tert-butyldiphenylsilyl)oxy-4-pentenoate in high yield. This means that the double bond conjugated with the ester moiety migrates to a deconjugated position by a ruthenium catalyst. We planned to prepare an enol ether from alpha,beta-unsaturated compounds having an ether moiety in a tether using ruthenium-catalyzed isomerization of the double bond. As a result, silyl or benzyl enol ether was obtained from the alpha,beta-unsaturated ester having alcohol protected by the silyl or benzyl group in a tether in high yield. In this reaction, double bond migration of alpha,beta-unsaturated ketone and alpha,beta-unsaturated amide took place to produce deconjugated compounds. Moreover, the double bond of alpha, beta-unsaturated ester having a triple or double bond in a molecule migrated to produce conjugated enyne and diene. On the other hand, treatment of a bis-metalated compound having an alpha, beta-unsaturated ester moiety or the double bond in a tether with RuClH(CO)(PPh(3))(3) gave allyl bis-metalated compound in good yield. These compounds are useful units in synthetic organic chemistry.

Journal Article↗
PubMed2000

Members of the family caliciviridae (Norwalk virus and Sapporo virus) are the most prevalent cause of gastroenteritis outbreaks among infants in Japan.

Norwalk virus (NV) and Sapporo virus (SV) were approved as type species of the genus Norwalk-like viruses and the genus Sapporo-like viruses, respectively, within the family Caliciviridae. To clarify the importance of NV and SV as causes of gastroenteritis outbreaks in infants, stool samples obtained from 36 outbreaks of nonbacterial gastroenteritis that occurred during 1976-1995 in an infant home in Sapporo, Japan, were examined for diarrhea viruses using electron microscopy, enzyme immunoassays, reverse transcriptase-polymerase chain reaction (PCR), and sequencing of the PCR products. NV and SV were associated with 15 (42%) of the 36 outbreaks and were more prevalent than rotavirus (RV) A, which was associated with 10 (28%) of the 36 outbreaks. Our data indicate that NV and SV were the most common cause of outbreaks of viral gastroenteritis in infants and were indeed more prevalent than RV-A in Sapporo, Japan, during 1976-1995.

Caliciviridae Infections↗
PubMed2000

Cell-cycle regulation of the DNA topoisomerase IIalpha promoter is mediated by proximal CCAAT boxes: possible involvement of acetylation.

Expression of DNA topoisomerase (topo) IIalpha is cell-cycle-regulated, with its peak in G(2)/M and its lowest level in G(0)/G(1). In agreement with this expression pattern, we have shown that the topo IIalpha gene promoter shows cell-cycle-dependent activity, which is repressed in G(0)/G(1) and activated exclusively in G(2)/M. However, the promoter sequence reveals no canonical CDE/CHR motifs, repressor elements commonly found in promoters of late S/G(2)-activated genes. Here, we show that at least two of the three proximal inverted CCAAT boxes (ICBs) are responsible for the G(2)/M-specific activation of the topo IIalpha promoter. Using antibody supershift experiments, we identify NF-Y as the ICB-binding transcription factor. However, the expression profile and binding capacity of NF-Y were constant during the cell cycle, suggesting a more global mechanism in topo IIalpha promoter regulation. Interestingly, we find that trichostatin A (TSA), a specific histone deacetylase inhibitor, greatly enhances topo IIalpha promoter activity in an ICB-dependent manner. In addition, the effect of TSA is predominant in G(0)/G(1) and less obvious in G(2)/M. Our data, along with the recent findings that NF-Y associates in vivo with histone acetyltransferases (HATs), strongly suggest a mechanism, in which histone deacetylation plays a crucial role in the G(0)/G(1)-specific repression of the topo IIalpha promoter, and NF-Y recruits HATs to the promoter region, thereby stimulating histone acetylation and activating transcription in G(2)/M.

3T3 Cells↗
PubMed2000

Proposal for a new five-axis classification scheme for psychoses of epilepsy.

Based on an overview of the literature and a multicenter study in Japan, we propose a new five-axis classification scheme for psychoses of epilepsy: (1) epilepsy variables, (2) psychopathology variables, (3) ictus/EEG variables, (4) precipitating factors of psychoses, (5) organic background. A total of 128 patients, 63 males and 65 females, with epilepsy and psychoses were recruited from five treatment centers. A wide heterogeneity of psychoses of epilepsy was demonstrated and categorization by a single axis was shown to be inadequate. Cluster analysis revealed four subgroups characterized by their psychopathology, temporal relationship to seizure occurrence, and EEG changes during psychoses. By comparing with the control epileptic group without psychoses, higher rates of mild intelligence disturbance and abnormal findings by brain imaging were proven among the psychotic group. The scheme involves a dimensional representation of individual patients to capture the complexity of their clinical background and to relay clinical information accurately and systematically. It is believed to hold direct therapeutic implications and to contribute to promoting research by enabling accumulation of a large number of patients on a multicenter basis.

Journal Article↗
PubMed2000

Prostaglandin E1 improves hepatic encephalopathy produced by ischaemia-reperfusion liver injury in rats.

OBJECTIVE: To investigate the action of prostaglandin E1 on hepatic encephalopathy. DESIGN: Prospective, randomised, controlled animal study. SETTING: University animal laboratory. SUBJECTS: Male Wistar rats. INTERVENTIONS: After passive avoidance learning, acute liver failure was induced by occlusion of the left portal vein and the hepatic artery for 90 min. Then memory retention was evaluated 48 h later. The effects of prostaglandin E1 on memory retention were examined in animals treated with the agent systemically (intravenous injections with prostaglandin E1 twice before and after surgery, 20 microg/kg each time) and animals treated with the agent topically (intracerebroventricular injection with prostaglandin E1, 0.1 microg/h for 48 h beginning at liver ischaemia). MEASUREMENTS AND RESULTS: Marked damage was found on plasma analysis in animals subjected to liver ischaemia, and the memory retention was also impaired. Intravenous administration of prostaglandin E1 improved both the liver injury and memory retention. However, intracerebroventricular administration of prostaglandin E1 alleviated neither. CONCLUSION: These findings show that prostaglandin E1 contributes to the amelioration of hepatic encephalopathy by improving liver function.

Alprostadil↗
PubMed2000

Pediatric acoustic schwannoma showing rapid regrowth with high proliferative activity.

Acoustic schwannoma is a slow-growing tumor and usually occurs in adult patients. We report a rare pediatric case of acoustic schwannoma with high proliferative potential. A 10-year-old boy was diagnosed as having a right cerebellopontine angle tumor. The tumor was subtotally resected. Histological examination revealed a typical acoustic schwannoma with a few mitotic figures. Chromosomal analysis showed no abnormality on the long arm of chromosome 22 associated with neurofibromatosis type 2. The lesion re-grew rapidly as an acoustic schwannoma, necessitating subtotal resection on three occasions and CyberKnife radiosurgery. The immunohistochemical MIB-1 staining indices of the specimens obtained at the first, second, and third operations were 2.3%, 4.6% and 14.7%, respectively. The immunohistochemical proliferative potential of acoustic schwannoma is discussed.

Biomarkers, Tumor↗
PubMed2000

Anterior cruciate ligament augmentation under arthroscopy. A minimum 2-year follow-up in 40 patients.

We present a new surgical technique of anterior cruciate ligament (ACL) augmentation using autogenous hamstring tendons or allogenic fascia lata under arthroscopy for patients in whom considerable ACL remnants with mechanoreceptors are preserved. We review the clinical results of 40 patients who underwent this ACL augmentation, as assessed by manual instability tests, KT-2000 knee arthrometer, Lysholm and Gillquist score, joint position sense and magnetic resonance imaging (MRI), and compare them with those of ACL reconstruction. The side-to-side differences of anterior displacement measured by the KT-2000 knee arthrometer at 30 lbs, an average of 5.3 +/- 2.6 mm preoperatively, was significantly improved to an average of 0.7 +/- 1.8 mm in the augmentation group, while an average of 6.0 +/- 2.4 mm was improved to 1.8 +/- 2.1 mm in the reconstruction group. There was no statistically significant difference between the preoperative values in the two groups, but the postoperative values of the augmentation group were significantly less than those of the reconstruction group. The ratio of anterior terminal stiffness of the augmentation group was 1.2 +/- 1.8, and that of the ACL reconstruction group was 0.7 +/- 0.4. This was a statistically significant difference (P < 0.05). Thus, as for the KT-2000 knee arthrometer, the ACL augmentation group showed significantly better anteroposterior stability and terminal stiffness than the ACL reconstruction group. The final inaccuracy of joint position sense of the augmentation group was 0.7 degrees +/- 0.7 degrees, while that of the reconstruction group was 1.7 degrees +/- 1.2 degrees indicating a significant difference (P < 0.05). This study demonstrates that ACL augmentation, which can preserve ACL remnants with mechanoreceptors, is superior to ACL reconstruction from the viewpoint of position sense and joint stability.

Adolescent↗