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Biomedical subjects

F Nakamura

Publications and source records attributed to F Nakamura.

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

Comparison of Bassini repair and mesh-plug repair for primary inguinal hernia: a retrospective study.

The purpose of this study was to compare the mesh-plug repair with the Bassini repair for the treatment of primary unilateral inguinal hernias. Patients with primary unilateral inguinal hernias who underwent a Bassini repair (n = 118) between January 1992 and May 1996 and a mesh-plug repair (n = 113) between July 1996 and April 1998 were retrospectively reviewed. We recorded information regarding the types of hernia according to Nyhus classification, operation time, complications, postoperative recovery, and recurrence after surgery. The two groups were comparable regarding age, sex, side of hernia, types of hernia, and the follow-up interval. The operation time was 55 +/- 20min for Bassini repair and 54 +/- 18min for mesh-plug repair. There was no incidence of mesh infection in the mesh-plug repair cases. The amount of diclofenac sodium (suppository) was 307 +/- 222mg in the Bassini repair group and 132 +/- 182mg in the mesh-plug repair group (P < 0.0001). The length of hospital stay was 8.2 +/- 2.0 days in the Bassini repair group and 4.3 +/- 2.7 days in the mesh-plug repair group (P < 0.01). Nine patients (7.6%) in the Bassini repair group had recurrence, compared with one patient (0.9%) in the mesh-plug repair group. The recurrence-free survival in the mesh-plug repair group was significantly longer than that in the Bassini repair group (P = 0.03). In conclusion, patients with primary unilateral inguinal hernias who undergo a mesh-plug repair recover more rapidly and have less recurrence in comparison with those who undergo a Bassini repair.

Aged↗
PubMed2001

Evaluation effects of chitosan for the extracellular matrix production by fibroblasts and the growth factors production by macrophages.

Chitosan is reported as an accelerator of wound healing. Histological findings of previous reports indicate that chitosan accelerates the reformation of connective tissue, however the details of the mechanism are not clear. In this study, firstly L929 mouse fibroblasts were cultured with chitosan and the production of extracellular matrix (ECM) was evaluated in vitro. Type I and III collagens and fibronectin were secreted by L929 with or without chitosan; however there was no significant difference in the amount of ECM between the control and the chitosan groups. Secondly, macrophages were stimulated with chitosan, and then transforming growth factor-beta 1 (TGF-beta1) and platelet-derived growth factor (PDGF) messenger ribonucleic acid (mRNA) expressions and production of their proteins were assayed in vitro. As a result, chitosan promoted the production of TGF-beta1 and PDGF. These results indicate that chitosan does not directly accelerate ECM production by fibroblast and the ECM production may increase by the growth factors.

Animals↗
PubMed2001

Initial changes of non-traumatic osteonecrosis of femoral head in fat suppression images: bone marrow edema was not found before the appearance of band patterns.

The present study examined initial changes in non-traumatic osteonecrosis of the femoral head (ONF) on T1- and T2-weighted MR images, and fat suppression images. The subjects were 57 renal transplant recipients (37 males and 20 females), whose median age at the time of transplantation was 31.5 years old (range, 10 to 58 years). Twelve patients developed band patterns (sign of established ONF) at an early postoperative period. Among them, 4 joints of 3 patients had a localized, faint signal abnormality in fat suppression images, where band pattern was confirmed later in T1- and T2-weighted images. In all the 57 patients, no bone marrow edema preceding to ONF was observed. Bone marrow edema would not be the cause of ONF in renal transplant patients. Early changes depicted in our fat suppression images would be useful information in the studies on pathogenesis of ONF.

Adult↗
PubMed2001

Effects of bright light at lunchtime on sleep of patients in a geriatric hospital I.

The effects of lunchtime bright light exposure in patients of a geriatric hospital were investigated. Ten inpatients (six women and four men; mean age +/- SD: 81.2 +/- 8.8 years) with sleep disturbances were studied for 9 weeks. Nurses performed daily ratings for sleep-wakefulness disturbances. Approximately 8000 lx bright light exposure was performed for 3 weeks in the light therapy room. Before and after exposure, ocular function was evaluated. Clinical ratings of sleep-wakefulness improved in eight patients. The score of difficulty in falling asleep and drowsiness in the morning declined during the light exposure. The score of drowsiness in the afternoon decreased during the post-light exposure. Post-exposure ocular disturbances were not found.

Aged↗
PubMed2001

Effects of bright light at lunchtime on sleep in patients in a geriatric hospital II.

Inpatients with sleep disturbances in a geriatric hospital received 1 h of exposure to approximately 8000 lx bright light per day for 3 weeks. Polysomnogram was recorded for four female patients. Two (aged 68 and 87 years) were non-demented patients with weak cataracts and the other two (aged 92 and 93 years) were demented patients with severe cataracts. Electroencephalogram results showed that light exposure decreased the proportion of Stage W, while increased the proportion of Stage 2, and these effects continued for at least 3 weeks after the cessation of light exposure. These results suggest that exposure to bright light is effective in improving the disturbed sleep of patients.

Aged↗
PubMed2001

Hydrophilic and hydrophobic bile acids exhibit different cytotoxicities through cytolysis, interleukin-8 synthesis and apoptosis in the intestinal epithelial cell lines. IEC-6 and Caco-2 cells.

BACKGROUND: Bile acids have been shown to exhibit varying degrees of cytotoxicity, depending on their hydrophobic-hydrophilic balance. We have recently reported the strong cytotoxicity of hyodeoxycholic acid (HDCA), and the aim of the present study is to investigate the mechanisms underlying the cytotoxicity of HDCA. METHODS: The intestinal cell lines IEC-6 and Caco-2 cells were used. The cytotoxicities of various bile acids were evaluated using the MTS assay; their cytolytic effects were measured using the LDH release assay. The induction of apoptosis was determined by the specific figure changes in the cellular cytoplasm and nucleus, including DNA ladder formations. IL-8 synthesis induced by the bile acids was measured using an ELISA assay. RESULTS: The bile acids induced cytotoxic effects, LDH release, IL-8 synthesis and apoptosis, depending on their hydrophobic properties. On the other hand, HDCA induced strong cytotoxicity, apoptosis and IL-8 synthesis but not cytolysis, although HDCA has a hydrophilic nature. In addition, HDCA exerted the strongest effects on dispersing monolayer cells. CONCLUSIONS: These results strongly suggest that HDCA induces cytotoxicity through its ability to induce apoptosis rather than its detergent effect.

Apoptosis↗
PubMed2001

Clinical advantages of interictal SPECT coregistered to magnetic resonance imaging in patients with epilepsy.

PURPOSE: The aim of this study was to investigate the clinical value of coregistration of interictal SPECT and magnetic resonance imaging (MRI) in patients with partial epilepsy. MATERIALS AND METHODS: Seventeen patients with partial epilepsy were examined with I-123 IMP or Tc-99m ethyl cysteinate dimer SPECT during the interictal phase. The SPECT images were automatically coregistered to axial T1 weighted MRIs. Asymmetry indexes (AIs) were calculated in both nonregistered images and coregistered images. RESULTS: SPECT images showed areas of decreased tracer uptake in 12 patients. In two patients, the relation between the tumor and the extent of decreased uptake became more accurate in the coregistered images. In five cases, the coregistered images clearly showed that the decreased uptake was located in the sulcus. The AIs were significantly reduced from 14.29 +/- 7.23 to 5.86 +/- 3.48 (P < 0.001) after the images were coregistered in these cases. In five cases, the coregistered images indicated that the decreased areas were in agreement with the cortical findings. No significant differences in the AIs were observed in these cases (16.50 +/- 6.19 versus 17.83 +/- 4.45). Thus, the coregistered images were useful not only to differentiate actual hypoperfusion from artificial hypoperfusion resulting from partial volume effects but also to improve the accuracy of AIs. CONCLUSION: The coregistration of interictal perfusion SPECT and MRI is useful not only to provide precise functional and anatomic mapping but also to improve the accuracy of calculations of the semiquantitative analysis of regional cerebral blood flow parameters during the interictal state of epilepsy.

Adolescent↗
PubMed2001

Thalamic asymmetry on interictal SPECT in patients with frontal lobe epilepsy.

BACKGROUND: Interictal brain single photon emission computed tomography (SPECT) is useful for the detection of seizure focus. Recent reports indicate a hypoperfusion in the ipsilateral thalamus as a seizure focus on interictal SPECT in temporal lobe epilepsy. In frontal lobe epilepsy (FLE), however, the alteration of perfusion in the thalamus has not been well documented. This study aimed to assess whether perfusion analysis on the thalamus may add useful information for the detection of epileptic foci in patients with FLE. METHODS: Interictal brain SPECT was performed in 11 patients with FLE. The asymmetry index for the thalamus and frontal area in the SPECT image was calculated in order to compare the laterality of the seizure foci. RESULTS: Thalamic asymmetry was seen in seven patients (64%), while cortial asymmetry was seen in six patients (55%). The concordance with the lateralization of the seizure foci was 6/7 (86%) in the thalamus, and 4/6 (67%) in the frontal area. Four patients showed only thalamic asymmetry. Concordance with the lateralization of the seizure focus was found in all of them. CONCLUSION: These preliminary results suggest that hypoperfusion in the thalamus may have a complementary role to lateralize the epileptic foci in patients with FLE.

Adolescent↗
PubMed2001

Effects of synthetic serine protease inhibitors on proliferation and collagen synthesis of human pancreatic periacinar fibroblast-like cells.

Protease inhibitors are currently used as therapeutic agents for chronic pancreatitis in Japan. We previously reported that human pancreatic periacinar fibroblast-like cells (hPFCs) could be cultured from isolated pancreatic acini, and those are thought to play a crucial role in pancreatic fibrosis correlating with platelet-derived growth factor (PDGF) and transforming growth factor beta1 (TGF-beta1) (Pancreas 1997;14: 373-82). The present study was designed to examine the effects of synthetic serine protease inhibitors (FOY-007 and FOY-305) on proliferation and collagen synthesis of hPFCs under cytokine stimulation. The cell proliferation and collagen synthesis were evaluated using assays of [3H]-thymidine incorporation and procollagen type I c-terminal peptide (PIP), and [14C]-proline incorporation to de novo synthesized collagen, respectively. The cell proliferation stimulated by PDGF was inhibited by the application of FOY-007 dose dependently (1-100 microM) and FOY-305 at 100 microM. FOY-007 attenuated the collagen synthesis and PIP production stimulated by TGF-beta1 dose dependently, but FOY-305 inhibited only PIP production. Both protease inhibitors demonstrated no effect on the proliferation and collagen synthesis of hPFCs when they were not stimulated by PDGF or TGF-beta1. Thus, serine protease inhibitors act on hPFCs to diminish the effects of PDGF on proliferation and the effects of TGF-beta1 on collagen synthesis.

Cell Division↗
PubMed2001

Enterostatin (VPDPR) has anti-analgesic and anti-amnesic activities.

Enterostatin (VPDPR), an anorexigenic peptide derived from the amino terminus of procolipase, significantly inhibited analgesia induced by the mu-opioid agonist morphine (5 mg/kg, s.c.) after i.c.v. administration to mice at a dose of 100 nmol. On the other hand, VPDPR (approximately 200 nmol, i.c.v.) did not attenuate analgesia induced by the kappa-opioid agonist D-Phe-D-Phe-D-Nle-D-Arg-NH2 (100 microg/mouse, i.c.v.) or delta-opioid agonist DTLET (4 nmol/mouse, i.c.v.). VPDPR (100 nmol, i.c.v.) significantly improved amnesia induced by scopolamine (0.2 mg/kg, i.p.) in mice. However, VPDPR did not enhance memory in normal mice at the same dose.

Adjuvants, Anesthesia↗
PubMed2001

Reversible left ventricular systolic dysfunction--reversibility of coronary microvascular abnormality.

Reversible left ventricular wall motion abnormalities mimicking myocardial infarction have been reported in patients with a noncardiac illness. Their coronary angiograms do not demonstrate organic stenosis or epicardial coronary vasospasm. In this article, two cases of reversible left ventricular contraction abnormality are presented. Electrocardiography showed deep inverted T waves in precordial leads, and the echocardiography revealed diffuse akinesis of the apical region in the acute phase. Coronary angiography showed no significant stenosis or occlusion in either patient. Thallium scintigraphy showed no defect, while the metaiodobenzylguanidine scintigraphy demonstrated significant defects in the apex. The relative coronary flow reserve ratio, measured with an intracoronary Doppler flow wire, was significantly reduced in both patients. Myocardial contrast echocardiography revealed a reversible perfusion defect in the apex in the acute phase in case 2. Transiently impaired coronary microcirculation was thought to be involved in the pathogenesis of the reversible left ventricular dysfunction observed in these patients.

Aged↗
PubMed2001

Successful catheter intervention for acute coronary syndrome in a patient with antiphospholipid syndrome.

Antiphospholipid syndrome (APS) has the clinical manifestations of systemic vascular thrombotic disorders. Although coronary events are infrequent, they have been described. Early coronary interventions and vein graft bypass frequently failed because of thrombosis. Here we present a case of successful coronary intervention and management of acute coronary syndrome under a strictly controlled coagulation state in an APS patient.

Anticoagulants↗
PubMed2000

Potentiation of a voltage-gated proton current in acidosis-induced swelling of rat microglia.

Microglia are equipped with a strong proton (H(+)) extrusion pathway, a voltage-gated H(+) channel, probably to compensate for the large amount of H(+) generated during phagocytosis; however, little is known about how this channel is regulated in pathological states. Because neural damage is often associated with intracellular and extracellular acidosis, we examined the regulatory mechanisms of the H(+) current of rat spinal microglia in acidic environments. More than 90% of round/amoeboid microglia expressed the H(+) current, which was characterized by slow activation kinetics, dependencies on both intracellular and extracellular pH, and blockage by Zn(2+). Extracellular lactoacidosis, pH 6.8, induced intracellular acidification and cell swelling. Cell swelling was also induced by intracellular dialysis with acidic pipette solutions, pH 5.5-6.8, at normal extracellular pH 7.3 in the presence of Na(+). The H(+) currents were increased in association with cell swelling as shown by shifts of the half-activation voltage to more negative potentials and by acceleration of the activation kinetics. The acidosis-induced cell swelling and the accompanying potentiation of the H(+) current required nonhydrolytic actions of intracellular ATP and were inhibited by agents affecting actin filaments (phalloidin and cytochalasin D). The H(+) current was also potentiated by swelling caused by hypotonic stress. These findings suggest that the H(+) channel of microglia can be potentiated via cell swelling induced by intracellular acidification. This potentiation might operate as a negative feedback mechanism to protect microglia from cytotoxic acidification and hence acidosis-induced swelling in pathological states of the CNS.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed2000

Semaphorin3A enhances endocytosis at sites of receptor-F-actin colocalization during growth cone collapse.

Axonal growth cone collapse is accompanied by a reduction in filopodial F-actin. We demonstrate here that semaphorin 3A (Sema3A) induces a coordinated rearrangement of Sema3A receptors and F-actin during growth cone collapse. Differential interference contrast microscopy reveals that some sites of Sema3A-induced F-actin reorganization correlate with discrete vacuoles, structures involved in endocytosis. Endocytosis of FITC-dextran by the growth cone is enhanced during Sema3A treatment, and sites of dextran accumulation colocalize with actin-rich vacuoles and ridges of membrane. Furthermore, the Sema3A receptor proteins, neuropilin-1 and plexin, and the Sema3A signaling molecule, rac1, also reorganize to vacuoles and membrane ridges after Sema3A treatment. These data support a model whereby Sema3A stimulates endocytosis by focal and coordinated rearrangement of receptor and cytoskeletal elements. Dextran accumulation is also increased in retinal ganglion cell (RGC) growth cones, in response to ephrin A5, and in RGC and DRG growth cones, in response to myelin and phorbol-ester. Therefore, enhanced endocytosis may be a general principle of physiologic growth cone collapse. We suggest that growth cone collapse is mediated by both actin filament rearrangements and alterations in membrane dynamics.

Actins↗
PubMed2000

Identification of the Nogo inhibitor of axon regeneration as a Reticulon protein.

Adult mammalian axon regeneration is generally successful in the peripheral nervous system (PNS) but is dismally poor in the central nervous system (CNS). However, many classes of CNS axons can extend for long distances in peripheral nerve grafts. A comparison of myelin from the CNS and the PNS has revealed that CNS white matter is selectively inhibitory for axonal outgrowth. Several components of CNS white matter, NI35, NI250(Nogo) and MAG, that have inhibitory activity for axon extension have been described. The IN-1 antibody, which recognizes NI35 and NI250(Nogo), allows moderate degrees of axonal regeneration and functional recovery after spinal cord injury. Here we identify Nogo as a member of the Reticulon family, Reticulon 4-A. Nogo is expressed by oligodendrocytes but not by Schwann cells, and associates primarily with the endoplasmic reticulum. A 66-residue lumenal/extracellular domain inhibits axonal extension and collapses dorsal root ganglion growth cones. In contrast to Nogo, Reticulon 1 and 3 are not expressed by oligodendrocytes, and the 66-residue lumenal/extracellular domains from Reticulon 1, 2 and 3 do not inhibit axonal regeneration. These data provide a molecular basis to assess the contribution of Nogo to the failure of axonal regeneration in the adult CNS.

Amino Acid Sequence↗