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Hiroshi Higuchi

Publications and source records attributed to Hiroshi Higuchi.

18 recordsLinked to original sources
PubMed2006

Potentiation by neuropeptide Y of histamine H1 receptor-mediated contraction in rat blood vessels.

Histamine-induced contraction and its potentiation by neuropeptide Y were investigated in rat blood vessels. Rat arteries and veins constricted with single concentrations of histamine dose-dependently (0.1-100 microM). This histamine-induced contraction immediately desensitized. Histamine H1 receptor antagonists, 1 microM mepyramine and 1 microM diphenhydramine, abolished this transient contraction completely, whereas cimetidine, phentolamine, reserpine and tetrodotoxin failed to inhibit the contraction. Histamine H1 receptor mRNA level by reverse transcription-polymerase chain reaction was quite parallel to histamine H1 receptor-mediated contraction, indicating that the contraction is mediated through histamine H1 receptors in the smooth muscle. Neuropeptide Y (10 nM in arteries and 3 nM in veins, respectively) significantly potentiated histamine H1 receptor-mediated contraction via neuropeptide Y1 receptors in most of rat blood vessels. Since the phospholipase C inhibitors, neomycin (1 mM) and 2-nitro-4-carboxyphenyl-N, N-diphenylcarbamate (NCDC, 10 microM), respectively, specifically abolished the potentiation, the potentiation by neuropeptide Y may depend on activation of phospholipase C.

Animals↗
PubMed2006

Potentiation by neuropeptide Y of 5HT2A receptor-mediated contraction in porcine coronary artery.

Potentiation by neuropeptide Y of serotonin (5-HT)-induced vasoconstriction was investigated in porcine coronary artery. 5-HT caused concentration-dependent contraction through 5-HT2A receptors. Neuropeptide Y (30 nM) significantly increased the 5HT-induced contraction by 16+/-5% in arteries with intact endothelium. Removal of the endothelium abolished the potentiation. A neuropeptide Y1 antagonist, BIBP3226, blocked this neuropeptide Y-induced potentiation. In vessels with intact endothelium, the potentiation by neuropeptide Y was inhibited by in the presence of a cyclo-oxygenase inhibitor, indomethacin (30 microM), but not by the presence of ETA or ETB endothelin receptor antagonists or an NO synthase inhibitor, NG-nitro-L-arginine (L-NNA) (1 mM) at all. A thromboxane A2 (TXA2) synthase inhibitor, ozagrel, and prostanoid TP receptor antagonists, seratrodast and ONO-3708, also inhibited the neuropeptide Y-induced potentiation. In the endothelium-denuded arteries, a prostanoid TP receptor agonist, U-46619 (0.01-0.1 nM), potentiated 5-HT-induced contraction. These results indicate that neuropeptide Y potentiates the 5-HT-induced contraction, due to release of TXA2 from the endothelium via neuropeptide Y1 receptors, in porcine coronary artery.

Animals↗
PubMed2005

Transcriptional regulation of neuronal genes and its effect on neural functions: transcriptional regulation of neuropeptide Y gene by leptin and its effect on feeding.

Leptin is an adipose tissue-derived secretory hormone that suppresses appetite by inhibition of neuropepeptide Y (NPY) gene expression in arcuate nucleus (ARC) in the hypothalamus. To investigate the transcriptional regulation of NPY gene by leptin, we carried out a luciferase assay using NPY gene promotor plasmid (NPY-luc) in NPY expressing cells such as N18TG2, NG108-15, and PC12 cells. In these cells, the NPY gene was transactivated by leptin through activation of leptin receptor. Leptin-induced transactivation was mediated through the 221-bp region of the NPY gene promotor, which possesses two putative STAT3 binding sites. To investigate the mechanism of in vivo suppression of NPY gene transcription in ARC by leptin, the effect of SOCS members on the leptin-induced transactivation of NPY gene was studied. In vivo SOCS2 and SOCS3 mRNAs were induced in mouse hypothalamus by leptin. Although leptin (125 ng/ml) induced significant increase in NPY gene transcriptional activity in mock-transfected cells, the leptin-induced NPY gene transcriptional activity was completely abolished in SOCS3-transfected cells. SOCS3 also suppressed the basal NPY gene transcription. These finding suggested that leptin inhibits NPY gene transcription in the hypothalamus in vivo and SOCS3 is a negative regulator of the NPY gene.

Animals↗
PubMed2005

Histological and biochemical changes of experimental meniscus tear in the dog knee.

BACKGROUND: When degeneration is noted in the meniscus, sutures should not be applied even for a tear of the vascularized region of the meniscus because the meniscus may rerupture after suturing. In this study, the degeneration process of bucket-handle tear of the meniscus was investigated using histological and biochemical markers. METHODS: A bucket-handle tear in the intercondylar notch was prepared in the dog knee. Eight animals each were killed at 2, 4, 12, 24, and 48 weeks; and changes in the articular cartilage were observed. The cell count and morphology in the meniscus were investigated by hematoxylin and eosin staining, and glycosaminoglycans in the matrix were investigated by toluidine blue staining. Glycosaminoglycans were also measured by high-performance liquid chromatography. RESULTS: Erosion was noted in the weight-bearing region of the articular cartilage after 12 weeks. The cell count in the meniscus was markedly decreased at 48 weeks. Regarding cell morphology, fibrochondrocytes remained in the meniscus until 12 weeks. The cell morphology varied at 24 weeks, but the number of cells was maintained. Cell proliferation, mainly fibroblasts, was noted from 2 weeks and 4 weeks after surgery in the periphery and body of the meniscus, respectively. Fibrochondrocyte-like cells proliferated from 12 weeks in the meniscal body, and metachromasia was detected by toluidine blue staining, indicating meniscal repair. A marked decrease in glycosaminoglycans was noted at 48 weeks, which was consistent with the decrease in the cell count in the meniscus. CONCLUSIONS: Early application of sutures is desirable for bucket-handle tear of the meniscus because lesions appear in the cartilage within 12 weeks, but suturing may be performed until 24 weeks because of the absence of obvious meniscal degeneration. However, disorder of the meniscus progresses after 48 weeks and may affect the outcome of the meniscal suture.

Animals↗
PubMed2004

Proprioception and performance after anterior cruciate ligament rupture.

The aim of this study was to investigate the characteristics of proprioception in patients with an anaterior-cruciate-ligament (ACL)-injured knee and to determine whether there is a correlation between proprioception and performance. We studied 32 patients with unilateral isolated ACL ruptures. Proprioception of the knee was evaluated by examining the joint position sense. Functional performance was evaluated with the one-leg hop (OLH) and one-leg vertical jump (OLV) tests. The mean error angle of the joint position sense was 3.6+/-1.5 degrees on the intact side and 5.2+/-1.9 degrees on the injured side. The joint position sense was thus clearly reduced on the injured side (p<0.05). The distance of jumping in the OLH test and the height of jumping in the OLV test was also clearly reduced on the injured side compared with that on the intact side (p<0.01) both with and without visual control. Moreover, we found a significant correlation between proprioception and performance in the ACL-injured knees, and this correlation was more distinct with visual deprivation. In conclusion, decreased proprioception in patients with ACL deficiency reduced their functional ability.

Adolescent↗
PubMed2004

Arthroscopic thermal shrinkage for hypermobile lateral meniscus.

BACKGROUND: The posterior segment of the lateral meniscus is relatively mobile as compared with that of the medial meniscus; that is because of its characteristic anatomy. Abnormal mobility of the lateral meniscus with no obvious rupture can be an unusual cause of knee pain and locking during deep knee flexion. PURPOSE: To evaluate results for a small series of patients with hypermobile lateral meniscus, treated with thermal shrinkage of the supporting ligaments. STUDY DESIGN: Series of case reports. METHOD: Five patients with hypermobile lateral meniscus were identified out of 625 patients who underwent meniscus surgery over a 20-month period. Thermal energy was applied to the peripheral zone of the lateral meniscus until abnormal translation was reduced. The patients were followed up an average of 21 months after the surgery. RESULTS: In 4 patients, no recurrence of locking was encountered in the postoperative period. In 1 patient, locking was experienced again 3 months after surgery and meniscal repair was performed. CONCLUSIONS: Thermal shrinkage can be considered an appropriate treatment in place of subtotal meniscectomy or meniscal repair for hypermobility of the lateral meniscus.

Adolescent↗
PubMed2004

A novel treatment of hypermobile lateral meniscus with monopolar radiofrequency energy.

Orthopedic treatment with radiofrequency energy (RFE) was first used in shoulder surgery, and its effectiveness has been reported. The purpose of RFE treatment of soft tissue is to induce qualitative changes in collagen and obtain stability. Hypermobile lateral meniscus (HLM) is characterized by abnormal mobility resulting from rupture or defects of the popliteomeniscal fasciculi, but no satisfactory treatment has been reported. We followed up patients with HLM who underwent monopolar RFE treatment and confirmed its short-term effects by magnetic resonance imaging and second-look arthroscopy.

Adolescent↗
PubMed2004

Eight- to 14-year followup of arthroscopic meniscal repair.

The current study aims to elucidate the midterm to long-term progression of arthroscopic meniscal repair which had been confirmed through a second-look arthroscopy at an average of 10 months after repair. Twenty-eight menisci of 28 patients were investigated at 8 to 14 years (mean, 10.2 +/- 1.8 years), eight after isolated meniscal repair (Isolated group) and 20 after concomitant anterior cruciate reconstruction (Anterior cruciate ligament group). All were rated excellent except four that rated good in the anterior cruciate ligament group as indicated by Lysholm's score at followup. None of the Isolated group, but 12 of the Anterior cruciate ligament group, had osteoarthritic changes seen on radiographs. Four and 19, respectively, had increased signal intensity on magnetic resonance imaging scans, 10 in the Anterior cruciate ligament group had changes of Grade 3 severity. However, no meniscal signs or symptoms were present and no significant relationship between findings of radiographs and magnetic resonance imaging scans was apparent. Anterior cruciate reconstructed knees that were changed to Grade 3 severity as seen on magnetic resonance imaging scans had higher sagittal instability seen on stress radiography than knees with Grade 2 or less severe changes. The anterior laxity of the knees influenced the severity of meniscal signal changes on the magnetic resonance imaging scans.

Adolescent↗
PubMed2004

[Control of hospital infection of influenza: administration of neuraminidase inhibitor and cohort isolation of influenza patients].

Influenza can spread rapidly to patients and staff in hospitals when influenza is introduced by visitors, staff, or patients. In order to prevent and control outbreaks of influenza in hospitals, systematic management is important. This consists of a rapid diagnostic test, cohort isolation and administration of neuraminidase inhibitor. In the 2002-2003 season, 53 elderly patients were admitted to our hospital under the control of the system. The mean age was 78.8 years. We set 2 isolation rooms (10 beds) for influenza patients. Patients were isolated in the room for three days, administered oseltamivir immediately. Oral oseltamivir was well tolerated. Mean hospital stay was 10.7 days. 36 cases developed complications requiring antibiotics, and one patient developed a catheter related infection. Under the system, we could avoid cross infection of influenza. In two cases, nose swabs were taken for virus isolation every 12 hours and a rapid decline in virus shedding was observed after treatment.

Acetamides↗
PubMed2003

Leptin-induced transactivation of NPY gene promoter mediated by JAK1, JAK2 and STAT3 in the neural cell lines.

Neuropeptide Y (NPY) plays an important role in the central and sympathetic regulation of food intake and blood pressure. Although the NPY gene expression is regulated by a number of agents such as leptin, the mechanism responsible for leptin-induced regulation of the transcription of the NPY gene remains to be explored. In this study, the NPY gene promoter was transactivated by leptin in N18TG2, NG108-15 and PC12 cells which expressed the functional leptin receptor. The long isoform of leptin receptor (OB-Rb) could induce the transactivation, but the C-terminal truncated form (OB-Ra) could not. When dominant negative type of STAT3, JAK1 or JAK2 and was co-expressed, the leptin-induced transactivation was suppressed almost completely. The leptin-response element which confers NPY gene transactivation by leptin was determined in the 221-bp region of rat NPY gene promoter (-553/-335), where two STAT3-binding site-like elements (TCCAGTA) exist. These results indicated that activation of JAK1, JAK2 and STAT3 is necessary for leptin-induced transactivation of NPY gene through the leptin-response element in these neural cells.

Animals↗
PubMed2003

Neuropeptide Y selectively potentiates alpha1-adrenoceptor-mediated contraction through Y1 receptor subtype in rat femoral artery.

The aim of this study was to investigate the synergism between neuropeptide Y and other vasoconstrictors (phenylephrine and serotonin) and which neuropeptide Y receptor subtype is responsible for the neuropeptide Y-induced potentiation. Exogenous neuropeptide Y (10 nM) potentiated alpha1-adrenoceptor-mediated (PE-induced) contraction in rat femoral artery permissively without its direct action, but not in the thoracic aorta. In contrast, neuropeptide Y produced no change in serotonin-induced contraction in both arteries. Increasing concentrations of neuropeptide Y caused dose-dependent potentiation of the phenylephrine-induced contraction in the femoral artery. This potentiation was blocked by a selective neuropeptide Y-Y1 receptor antagonist, BIBP3226 [(R)-N2-(diphenylacetyl)-N-[4-hydroxyphenyl)methyl]-argininamide] (1 microM). Semiquantitative reverse transcriptase polymerase chain reaction showed the selective expression of neuropeptide Y-Y1 receptor mRNA in the femoral artery. These findings indicated that the neuropeptide Y-induced selective potentiation of alpha1-adrenoceptor-mediated contraction is mediated through neuropeptide Y-Y1 receptor in rat femoral artery.

Animals↗
PubMed2003

Neuropeptide Y-induced contraction and its desensitization through the neuropeptide Y receptor subtype in several rat veins.

Exogenous neuropeptide Y produced marked contractions in rat isolated common jugular, brachial, and caudal veins, while it produced little or no contractions in common carotid, brachial, and caudal arteries. Neuropeptide Y (30 nM) produced larger contractions in these veins than did phenylephrine (1 microM), with maximal contractions through the neuropeptide Y receptor and the alpha1-adrenoceptor, respectively. In contrast, neuropeptide Y (30 nM) produced smaller contractions than did phenylephrine (1 microM) in the arteries. Pre-treatment with neuropeptide Y (30 nM) showed remarkable desensitization to neuropeptide Y (30 nM). This desensitization lasted for 1 h in the caudal vein or for 2 h in the common carotid and brachial veins. The neuropeptide Y-induced contraction and its desensitization probably occurred through the neuropeptide Y receptor subtype Y1, because only the neuropeptide Y receptor subtype Y1 was detected in the smooth muscle by the reverse transcriptase-polymerase chain reaction.

Animals↗
PubMed2003

The relation between static and dynamic knee stability after ACL reconstruction.

The purpose of this prospective study was to quantify and compare the amount of anterior tibial translation (ATT) occurring in ACL-reconstructed knees during both a static passive Lachman test and an isokinetic knee extension exercise, pre- and postoperatively. Stress-radiography combined with an electrogoniometer system was applied to 49 knees before and after ACL reconstruction. The Lysholm score was calculated and subjective evaluation assessed before operation and at follow-up. Both measurement methods confirmed a significant decrease of ATT after surgery. Side-to-side differences in ATT were seen in the passive Lachman test postoperatively, and were not found during isokinetic extension from 90 degrees to 0 degree. There was no significant correlation between static passive stability and the functional knee score at follow-up. In addition, the patients with a more than 3 mm side-to-side difference in the passive Lachman test after surgery, showed less than a 1 mm side-to-side difference during isokinetic exercise at a flexion angle of 20 degrees. These results suggest that ACL reconstruction improves ATT in both tests, but the side-to-side difference is greater with the static Lachman test.

Adolescent↗
PubMed2003

[A case of primary meningeal melanocytoma of the left middle fossa].

A 29-year-old woman presented with a primary meningeal melanocytoma of the left middle fossa manifesting as headache and nausea. Computed tomography (CT) with contrast medium demonstrated a clearly demarcated, homogeneously enhanced high density area surrounded by a cyst in the left temporal lobe. Magnetic resonance (MR) imaging showed the mass as a slightly high signal intensity area on the T1-weighted image and as a low signal intensity area on the T2-weighted image. Cerebral angiography revealed shift of the middle cerebral artery but no tumor stain. The solid part of the tumor had rapidly increased in size with reduction of the cyst 3 months later. Left frontotemporal craniotomy disclosed a clearly demarcated jet-black tumor attached to the dura. The black-colored lesion in the dura and the bone extended to the skull base, so malignant melanoma was a possibility. The solid part of the tumor was gross totally removed, and the dura and the skull bone were preserved. Histological examination of the tumor specimen revealed meningeal melanocytoma. Melanophages were present in the specimen of the black-colored lesion in the dura and the bone, but no neoplastic infiltration was present. The postoperative course was uneventful, and the patient's headache and nausea disappeared. CT and MR imaging taken 1 month later confirmed total removal of the tumor. No recurrence has been observed for 2.5 years after surgery. Preoperative differentiation of meningeal melanocytoma from malignant melanoma is difficult, but the primary goal of therapy is gross total resection of the solid part of the tumor irrespective of tumor type.

Adult↗
PubMed2002

Characteristics of anterior tibial translation with active and isokinetic knee extension exercise before and after ACL reconstruction.

The aim of this study was to investigate the biomechanical characteristics of anterior tibial translation (ATT) in anterior cruciate ligament (ACL)-deficient or -reconstructed knees with active and isokinetic knee extension exercise. Forty-nine patients with unilateral isolated ACL-deficient knees were enrolled. Follow-up examinations were carried out at a mean of 24 months postoperatively. An electrogoniometer system was applied to compare the amount of ATT in ACL-deficient and -reconstructed knees. For both active and isokinetic knee extension, the mean ATT of ACL-deficient knees was considerably greater than that for the normal side, within a range of flexion 0 degrees -70 degrees and 0 degrees -60 degrees, respectively. In contrast, no mean ATT differences were seen during both active and isokinetic exercise from 90 degrees to 0 degrees at follow-up. Within a range of flexion between 50 degrees and 70 degrees, the side-to-side difference in ATT with active knee extension was significantly greater than that with isokinetic extension in ACL-reconstructed knees. These results suggest that the amount of ATT is significantly improved with both active and isokinetic exercise, postoperatively. However, postoperative ATT with isokinetic extension is smaller than that with active knee extension from 50 degrees to 70 degrees.

Adolescent↗
PubMed2002

Marked neuropeptide Y-induced contractions via NPY-Y1 receptor and its desensitization in rat veins.

The aim of this study was to investigate neuropeptide Y (NPY)-induced vasoconstrictions in rat blood vessels and which NPY receptor subtype is involved in vasoconstrictions. NPY produced marked contractions in rat common jugular, brachial, portal, femoral and tail veins, and vena cava inferior, whereas it produced little or no contractions in rat common carotid, brachial, femoral and tail arteries, and thoracic and abdominal aortae. The maximal NPY-induced contractions were larger than maximal phenylephrine (PE)-induced contractions in the veins. These NPY-induced contractions were blocked by the Y1 antagonists, SRL-21, and BIBP3226 but not by the Y5 antagonist, L-152804. A Y2 agonist, NPY (13-36), did not produce contractions. RT-PCR showed that NPY-Y1 was the only receptor subtype in the veins indicating that NPY-induced contractions are mediated through the Y1 receptor. Pretreatment with NPY showed a rapid and long-lasting desensitization of these contractions. The marked NPY-induced contractions and its desensitization in the veins suggest the physiological relevance of NPY in the venous circulation.

Algorithms↗
PubMed2002

Juxta-articular bone marrow signal changes on magnetic resonance imaging following arthroscopic meniscectomy.

PURPOSE: Postmeniscectomy osteonecrosis of the knee has been reported in the past decade but the etiology remains unclear. Some investigators have indicated that bone marrow signal changes evident on magnetic resonance imaging (MRI) could be early warning signs of osteonecrosis. The purpose of this study was to determine the incidence rate, location, and magnitude of such changes in bone marrow of the knee after arthroscopic meniscectomy, using MRI. TYPE OF STUDY: Cohort analytic study. METHODS: Ninety-three patients with no bone marrow signal abnormalities on preoperative MRI were examined after isolated arthroscopic meniscectomy. There were 51 men and 42 women with an age range of 11 to 62 years (mean, 36.6 years). Of the total, 57 patients underwent partial meniscectomy (34 medial and 23 lateral) and the others total meniscectomy (10 medial and 26 lateral). MRI examinations were performed independently of postoperative knee symptoms, 1 to 24 months after surgery. Bone marrow changes of the treated knees were evaluated by T1- and T2*-weighted MRI. RESULTS: Thirty-two of 93 patients (34%) had bone marrow signal changes in femoral or tibial condyles shown on postoperative MRI. No patients had these changes in the femoral or tibial condyles opposite from the meniscectomy side and, in the majority of cases, the size was less than half that of the condyle. Fifteen of the 44 patients who underwent medial meniscectomy and 17 of the 49 patients who underwent lateral meniscectomy had such changes. The meniscectomy side did not affect the incidence rate, and frequently both femoral and tibial condyles were involved. Age, gender and articular cartilage condition at the surgery were not risk factors. In contrast, the extent of meniscectomy affected the incidence rate. CONCLUSIONS: This study suggests a positive correlation between arthroscopic meniscectomy and postoperative bone marrow signal changes of the knee.

Adolescent↗