Biomedical subjects

M Naito

Publications and source records attributed to M Naito.

At least 55 records · Page 3Linked to original sources

PubMed2001

Supernumerary ring chromosomes in dermatofibrosarcoma protuberans may contain sequences from 8q11.2-qter and 17q21-qter: a combined cytogenetic and comparative genomic hybridization study.

Dermatofibrosarcoma protuberans (DFSP) presents with characteristic cytogenetic features such as reciprocal t(17;22)(q22;q13) or, more commonly, supernumerary ring chromosomes containing sequences from chromosomes 17 and 22. Here, we report the identification of a novel abnormality in a 43-year-old woman with DFSP. Cytogenetic analysis of tumor cells showed the presence of a supernumerary ring chromosome as the sole anomaly. Amplification of 8q11.2 approximately qter and 17q21 approximately qter sequences was confirmed by comparative genomic hybridization (CGH); the present case apparently lacked amplification of chromosome 22. To our knowledge, this is the first case indicating that the ring chromosome in DFSP is possibly associated with amplified material from chromosomes 8 and 17.

Adult↗

PubMed2001

The effect of surgical dissections on blood flow to the tibial tubercle.

Tibial tubercle transfer is often used for the treatment of patella maltracking. Because the periosteum of both sides of the tibia is stripped off along the tibial tubercle and then the bilateral cortices are transferred, this procedure may disturb the blood supply to the tibial tubercle. However, the blood supply to the tibial tubercle has not yet been clearly elucidated. The purpose of this study is to investigate the effect of surgical dissection on blood flow to the tibial tubercle in an animal model using a hydrogen washout technique. Eleven knees of nine mongrel dogs weighing from 7.0 to 19.1 kg were utilized. The blood flow was measured using a hydrogen washout technique. Before performing the surgical procedures, the control blood flow rate of the tibial tubercle averaged 19.6 ml/min per 100 g of tissue. The blood flow rate did not significantly decrease after transecting the periosteum on the lateral side of the tibia alone (P > 0.05). After completing the tibial tubercle osteotomy, the blood flow rate averaged 11.5 ml/min per 100 g of tissue, which is a 25.3% decrease as compared with the value after transecting the periosteum on the lateral side of the tibia alone (P < 0.05). The blood flow rate significantly decreased to 3.4 ml/min per 100 g of tissue after the distal periosteal transection and osteotomy of the distal cortex of the tibial tubercle (P < 0.05). The addition of a medial periosteal transection caused a complete arrest of the blood flow in 10 out of 11 knees, or a 91.2% decrease as compared with the value after a distal periosteal transection and osteotomy of the distal cortex of the tibial tubercle (P < 0.05).

Animals↗

PubMed2001

Japanese children's numerical competencies: age- and schooling-related influences on the development of number concepts and addition skills.

Using a cutoff design (J. Bisanz, F. J. Morrison, & M. Dunn, 1995) to separate school-related influences from those that are age related, the study investigated the development of number concepts and addition skills in Japanese children. Three groups of kindergarten and 1st grade children who differed in age and/or school experiences completed tasks on their numerical competencies 1 and 6 months after school entrance. Children's use of addition strategies, rather than their solution accuracy, changed primarily as a function of schooling, not age. Children's Base 10 number concepts improved with the amount of schooling, as well as with other social and age-related factors. Results suggest that schooling is an important determinant in developing Japanese-speaking children's numerical competencies, which were not explained solely by their language characteristics or by age-related factors.

Child↗

PubMed2001

Cloning of porcine IGF1 receptor cDNA and detection of sequence polymorphisms using RT-PCR.

A cDNA encoding the porcine type 1 insulin-like growth factor receptor (IGF1R) was amplified by reverse transcriptase-polymerase chain reaction (RT-PCR). The sequence of a 4.2-kb product was determined and had an open reading frame, encoding 1367 amino acids with 98.1 and 95.2% sequence similarity to the human and rat IGF1R, respectively. In the comparison of RT-PCR derived IGF1R sequences from 12 unrelated pigs, 12 silent sequence variants were found.

Animals↗

PubMed2001

A study on the measurement of occlusal force and masticatory efficiency in school age Japanese children.

AIM: The purpose of this study was to investigate the relationship between occlusal force and masticatory efficiency in school age Japanese children. SAMPLE: The subjects were 208 volunteer Japanese children from 7 to 9 years old. Occlusal force was measured using an MPM-3000 occlusal instrument and masticatory efficiency by adenosine bisodium triphosphate (ATP) particles. RESULTS: It is obvious from the results that the occlusal force of Japanese school age children is decreasing. A t-test of both masticatory efficiency and occlusal force showed no significant sex differences for children at 7 and 8 years old. However, 9 year-old boys showed significantly higher values compared with 9 year-old girls in both measurements. No significant difference was seen between 7 and 8 year-old children in both measurements. However, 9 year-old children showed significantly higher values when compared with 7 and 8 year-old children. Occlusal force and masticatory efficiency were shown to be correlated with chronological age, with a coefficient of more than 0.6.

Age Factors↗

PubMed2001

Immunological response to interferon-gamma priming prior to interferon-alpha treatment in refractory chronic hepatitis C in relation to viral clearance.

The aim of this study was to clarify the immunological and virological responses to pre-administration of interferon-gamma prior to initiation of interferon-alpha treatment in patients with refractory chronic hepatitis C. Twenty-two nonresponders to 6-months of IFN-alpha treatment were enrolled. The hepatitis C virus (HCV) genotype was Ib in all. Natural IFN-gamma (1 MIU/day) was administered daily for 14 days followed by natural IFN-alpha (5 MIU/day) daily for 14 days and then three times weekly for 22 weeks. Serum immunological parameters (IL-10, neopterin, BMG, sCD8, sCD4, IL-6, IL-12) were measured as were the levels of several cytokines (IFN-gamma, TNF-alpha, IL-2, IL-4, IL-5, IL-6, IL-10). Three patients dropped out; two because of the occurrence of other diseases and one because of an adverse effect. At the end of the period of IFN-alpha treatment, HCV-RNA had become negative in six of 19 patients (end-of treatment response; ETR). Six months after the completion of IFN administration, a virological sustained response (SR) was seen in two of 19 patients. The mean serum levels of IL-10 were significantly decreased 6 weeks after the start of treatment. Other immunological parameter levels increased significantly during the period of IFN-gamma administration, and tended to return to the pretreatment level after the start of IFN-alpha administration. Univariate logistic regression analysis showed that the initial change in the levels of these parameters or the change in the ratios of Th1/Th2 parameter levels are useful factors indicative of the end of the treatment response. These findings suggest that priming with IFN-gamma prior to the initiation of IFN-alpha treatment in patients with refractory chronic hepatitis C can modulate the host immune response and this might contribute to viral clearance.

Antiviral Agents↗

PubMed2001

Efflux of a suppressive neurotransmitter, GABA, across the blood-brain barrier.

In this study, GABA efflux transport from brain to blood was estimated by using the brain efflux index (BEI) method. [3H]GABA microinjected into parietal cortex area 2 (Par2) of the rat brain was eliminated from the brain with an apparent elimination half-life of 16.9 min. The blood-brain barrier (BBB) efflux clearance of [3H]GABA was at least 0.153 mL/min/g brain, which was calculated from the elimination rate constant (7.14 x 10(-2) x min(-1)) and the distribution volume in the brain (2.14 mL/g brain). Direct comparison of the apparent BBB influx clearance [3H]GABA (9.29 microL/min/g brain) and the apparent efflux clearance (153 microL/min/g brain) indicated that the efflux clearance was at least 16-fold greater than the influx clearance. In order to reduce the effect of metabolism in the neuronal cells following intracerebral microinjection, we determined the apparent efflux of [3H]GABA in the presence of nipecotic acid, a GABA transport inhibitor in parenchymal cells, using the BEI method. Under such conditions, the elimination of [3H]GABA across the BBB showed saturation and inhibition by probenecid in the presence of nipecotic acid. Furthermore, the uptake of [3H]GABA by MBEC4 cells was inhibited by GABA, taurine, beta-alanine and nipecotic acid in a concentration-dependent manner. It is likely that GABA inhibits the first step in the abluminal membrane uptake by brain endothelial cells, and that probenecid selectively inhibits the luminal membrane efflux transport process from the brain capillary endothelial cells based on the in vivo and in vitro evidence. The BBB acts as the efflux pump for GABA to reduce the brain interstitial fluid concentration.

Animals↗

PubMed2001

Carbon monoxide from heme catabolism protects against hepatobiliary dysfunction in endotoxin-treated rat liver.

BACKGROUND AND AIMS: Liver is a major organ for heme detoxification under disease conditions, but its self-protective mechanisms against the toxicity are unknown. This study aimed to examine roles of carbon monoxide (CO), the gaseous product of heme oxygenase (HO), in ameliorating hepatobiliary dysfunction during catabolism of heme molecules in endotoxemic livers. METHODS: Vascular resistance and biliary flux of bilirubin-IXalpha, an index of HO-derived CO generation, were monitored in perfused livers of endotoxemic rats. Livers were perfused with HbO(2), which captures nitric oxide (NO) and CO, or metHb, a reagent trapping NO but not CO. RESULTS: In endotoxin-pretreated livers where inducible NO synthase and HO-1 overproduced NO and CO, HbO(2) caused marked vasoconstriction and cholestasis. These changes were not reproduced by the NO synthase inhibitor aminoguanidine alone, but by coadministration of zinc protoporphyrin-IX, an HO inhibitor. CO supplementation attenuated the events caused by aminoguanidine plus zinc protoporphyrin-IX, suggesting that simultaneous elimination of these vasorelaxing gases accounts for a mechanism for HbO(2)-induced changes. This concept was supported by observation that metHb did not cause any cholestasis; the reagent captures NO but triggers CO overproduction through rapid degradation of the heme by HO-1. CONCLUSIONS: These results suggest protective roles of CO against hepatobiliary dysfunction caused by heme overloading under stress conditions.

Animals↗

PubMed2001

Kupffer cell-mediated recruitment of rat dendritic cells to the liver: roles of N-acetylgalactosamine-specific sugar receptors.

BACKGROUND & AIMS: Tissue recruitment of dendritic cells (DCs) is essential for antigen presentation. This study aimed to examine cellular and molecular mechanisms for DC recruitment to the liver. METHODS: Purified rat DCs were injected into circulation and their traffics were analyzed in normal and Kupffer cell-depleted rats by intravital confocal microscopy and immunohistology. Affinities of DCs to sinusoidal cells were examined by a cell-binding assay. DC precursor recruitment was induced by particulate injection. RESULTS: Both DC precursors and DCs at the antigen-transporting stage could be recruited to the liver, and their majority initially showed a selective binding to Kupffer cells. In the Kupffer cell-depleted rats, DCs could neither be recruited to the liver nor adhere to sinusoidal walls. Pretreatment with varied monosaccharides showed that sugar residues consisting of N-acetylgalactosamine were necessary for this binding. The binding was calcium-dependent, implying the C-type lectin involvement. Furthermore, DCs could endocytose N-acetylgalactosamine polymers in a receptor-specific manner. CONCLUSIONS: The DC-Kupffer cell binding through N-acetylgalactosamine-specific C-type lectin-like receptors is crucial for DC recruitment to the liver. Rat DCs at least partly possess receptors for endocytosis of galactosylated antigens. These DC receptors as well as Kupffer cell lectins are presumably responsible for this binding.

Acetylgalactosamine↗

PubMed2001

Arthroscopic debridement for dialysis shoulders.

PURPOSE: To arthroscopically treat "dialysis shoulder," severe shoulder pain in patients on long-term hemodialysis. This pain occurs only at rest such as during hemodialysis or while sleeping and is temporarily alleviated by assuming the sitting position or moving the shoulder joint. Limitations in range of motion and pain with overhead activity or the arm in the forward flexed position are not the patient's chief complaints. Although frozen shoulder and impingement syndrome may be observed as complications, pain at rest is the most characteristic. TYPE OF STUDY: Clinical research on arthroscopic debridement to treat dialysis shoulder. METHODS: We performed arthroscopic debridement of 36 dialysis shoulders in 29 patients. Only complete debridement in the glenohumeral joint and subacromial bursa was performed, without invasion to the bone and ligaments. RESULTS: The pain improved in 34 shoulders in 27 patients (94%) a mean of 29.8 months after surgery, showing satisfactory results. In this group, the mean Japan Orthopaedic Surgery Association shoulder score (maximum 100 points) was 66.4 points before surgery but increased to 86.6 points postoperatively, statistically significant by 2-group t test. CONCLUSIONS: We decided before beginning the study that no postoperative rehabilitation would be necessary. There were no complications and no need for further surgery, with all but 2 of the patients being satisfied with their postoperative condition.

Activities of Daily Living↗

PubMed2001

Potentiation by stannous chloride of calcium entry into osteoblastic MC3T3-E1 cells through voltage-dependent L-type calcium channels.

The present study was undertaken to confirm that L-type Ca(2+) channels are involved in Ca(2+) entry into osteoblastic MC3T3-E1 cells and to examine the effect of SnCl2, a Ca(2+)]-channel activator, on the intracellular Ca(2+)concentration ([Ca(2+)]i). High K(+)concentration-dependently raised the [Ca(2+)]i. All of the L-type Ca(2+)channel blockers used here, such as nifedipine, nicardipine, verapamil, and diltiazem, and CdCl2 (a non-selective blocker) inhibited the high K(+)-induced [Ca(2+)]i rise, but v-conotoxin GVIA (an N-type blocker) and NiCl2(a T-type blocker) had no effect. Application of SnCl2 alone did not change the [Ca(2+)]i. However, in the presence of high K(+), SnCl2 enhanced the high K(+)-induced [Ca(2+)]i rise, which was inhibited by Ca(2+)]-free medium or nifedipine. In the case where high K(+)was applied prior to SnCl2, SnCl2 alone raised the [Ca(2+)]i by itself. In conclusion, MC3T3-E1 cells possess the voltage-dependent L-type Ca(2+)] channels and SnCl2 facilitates the Ca(2+) entry through the L-type ones under the condition of the membrane depolarization. There is the possibility that Ca(2+) release from intracellular Ca(2+) stores is involved in the action of SnCl2.

3T3 Cells↗

PubMed2001

Measurement of median nerve blood flow during carpal tunnel release with laser Doppler flowmetry.

Eight consecutive median nerves in eight patients with clinical carpal tunnel syndrome were prospectively examined by non-contact laser Doppler flowmetry before and after undergoing carpal tunnel release. Before performing carpal tunnel release, the difference in the median nerve blood flow between the values at the distal and proximal portions to the transverse carpal ligament was statistically significant (p = 0.021). After carpal tunnel release, the median nerve blood flow both distal and proximal to the transverse carpal ligament increased by 1.5 and 1.3 times, respectively, compared to the flow prior to carpal tunnel release, however, only the difference at the distal portion to the transverse carpal ligament was statistically significant (p = 0.015). In this study, we directly measured the median nerve blood flow using non-contact laser Doppler flowmetry and thus demonstrated a significant difference in the median nerve blood flow between the values at the distal and proximal portions to the transverse carpal ligament before carpal tunnel release and a significant increase in the nerve blood flow only at the distal portion to the transverse carpal ligament after surgery. This technique is thus considered to be an easy and reproducible way to intraoperatively evaluate the nerve blood flow in real time during the release of entrapment neuropathies.

Aged↗

PubMed2001

Tumoral calcium pyrophosphate dihydrate crystal deposition disease. A clinicopathologic analysis of five cases.

We describe five cases of tumoral calcium pyrophosphate dihydrate crystal deposition disease (CPPDCD) and discuss the clinical, radiological and pathological features. Patients included 4 males and 1 female, ranging in age from 49 to 70 years (median, 63 yrs). The wrist was involved in two patients. The thumb, palmar aspect of the proximal phalanx of the middle finger and dorsum of the carpal bone of the hand were involved in one patient each. In one patient, a preoperative diagnosis of chondrosarcoma had been made. Macroscopically, the lesion was a circumscribed whitish-gray mass with a more or less chalky appearance, measuring between 1.0 to 6.2 cm (median, 2.5 cm). Histologically, all five lesions contained areas of calcification with crystal deposits and chondroid metaplasia. The majority of crystals were rhomboid in shape, characteristic of CPPD, but some needle-shaped crystals were also identified, which resembled urate crystals. A review of the 54 reported cases of tumoral CPPDCD including our series indicated that they could be divided into two categories based on anatomic location: central (head and neck) type (n = 33) and distal (extremity) type (n = 21). Patients of these two groups were not different with respect to age and gender, but those with the central type often presented with a painful mass (15 patients, 46%), or neurological disturbances (11 patients, 33%). Patients with the distal type presented with a painless mass or swelling (12 patients, 57%), but none had neurological signs, although 8 (38.1%) presented with acute attack similar to tophaceous gout. Tumoral CP-PDCD should be differentiated from tophaceous gout, tumoral calcinosis, and malignant or benign tumors.

Aged↗

PubMed2001

Skin antigens in the steady state are trafficked to regional lymph nodes by transforming growth factor-beta1-dependent cells.

Antigen capturing in the skin and antigen trafficking into regional lymph nodes (LN) initiate immune responses. In this study, employing melanin granule (MG) as an easily traceable antigen in two mouse strains that carried steel factor or hepatocyte growth factor transgenes and had melanocytosis in the epidermis or in the dermis respectively, we investigated the mechanism of antigen trafficking from the skin. MG captured in the epidermis or dermis accumulated in the regional LN, but not other tissues. Only in alymphoplastic mice did MG-laden cells pass through the lymphatics and reached many tissues. Since inflammatory regions were not observed in the skin of either type of transgenic mouse, our developmental system enables us to investigate constitutive capturing and trafficking of insoluble antigens in the steady state. Both dendritic cells and macrophages were laden with MG in the regional LN. To determine which cells traffic antigens to the LN, we prepared double mutants that carried the transgenes and lacked transforming growth factor (TGF)-beta1, since mice lacking TGF-beta1 are reported to be deficient of Langerhans cells. Few MG were observed in the regional LN of these double-mutant mice. We also showed that signaling via macrophage colony stimulating factor receptor or Flt3/Flk2 is not essential for development of the cells for this antigen trafficking. These results indicate that antigens in the epidermis and dermis in the steady state are trafficked into regional LN only by TGF-beta1-dependent cells, which may be a dendritic cell lineage.

Animals↗

PubMed2001

Surgical therapy for dialysis-related spondyloarthropathy: review of 30 cases.

Surgical therapy for dialysis-related spondyloarthropathy was investigated regarding its spinal manifestation. Between August 1985 and May 1998, 31 operations were performed on 16 male and 14 female patients; of these, 17 had cervical and 13 had lumbar spinal disorders. The average patient age was 59 years. The average period of hemodialysis was 14.8 years. Twenty-eight of 30 patients had cystic bone lesions and 24 had carpal tunnel syndrome. Four major postoperative complications occurred: death from paralysis and respiratory distress, severe kyphosis from the collapse of the grafted bone, deep infection from instrumentation, and wire breakage and bone fusion failure. Postoperative results with an average follow-up period of 2.7 years were good in 19 cases (63%), fair in 8 cases (27%), and poor in 3 cases (10%). As yet, surgical intervention for dialysis-related spondyloarthropathy is still regarded as a noncurative treatment; furthermore, the anterior approach to the cervical spine has a high risk for postoperative complications.

Aged↗

PubMed2001

Stability after medial collateral ligament release in total knee arthroplasty.

Six knees from cadavers were tested for change in stability after release of the medial collateral ligament with posterior cruciate-retaining and substituting total knee replacements. Load deformation curves of the joint were recorded in full extension and 30 degrees, 60 degrees, and 90 degrees flexion under a 10 N-m varus and valgus torque, 1.5 N-m internal and external rotational torque, and a 35 N anterior and posterior force to test stability in each knee. The intact specimen and posterior cruciate ligament-retaining total joint replacement were tested for baseline comparisons. The superficial medial collateral ligament was released, followed by release of the posterior cruciate ligament. The knee then was converted to a posterior-stabilized implant. After medial collateral ligament release, valgus laxity was statistically significantly greater at 30 degrees, 60 degrees, and 90 degrees flexion after posterior cruciate ligament sacrifice than it was when the posterior cruciate ligament was retained. The posterior-stabilizing post added little to varus and valgus stability. Small, but significant, differences were seen in internal and external rotation before and after posterior cruciate ligament sacrifice. The posterior-stabilized total knee arthroplasty was even more rotationally constrained in full extension than the knee with intact medial collateral ligament and posterior cruciate ligament.

Arthroplasty, Replacement, Knee↗

PubMed2001

Both caspase-dependent and caspase-independent pathways may be involved in hippocampal CA1 neuronal death because of loss of cytochrome c From mitochondria in a rat forebrain ischemia model.

In a rat forebrain ischemia model, the authors examined whether loss of cytochrome c from mitochondria correlates with ischemic hippocampal CA1 neuronal death and how cytochrome c release may shape neuronal death. Forebrain ischemia was induced by bilateral common carotid artery occlusion with simultaneous hypotension for 10 minutes. After reperfusion, an early rapid depletion of mitochondrial cytochrome c and a late phase of diffuse redistribution of cytochrome c occurred in the hippocampal CA1 region, but not in the dentate gyrus and CA3 regions. Intracerebroventricular administration of Z-DEVD-FMK, a relatively selective caspase-3 inhibitor, provided limited but significant protection against ischemic neuronal damage on day 7 after reperfusion. Treatment with 3 minutes of ischemia (ischemic preconditioning) 48 hours before the 10-minute ischemia attenuated both the early and late phases of cytochrome c redistribution. In another subset of animals treated with cycloheximide, a general protein synthesis inhibitor, the late phase of cytochrome c redistribution was inhibited, whereas most hippocampal CA1 neurons never regained mitochondrial cytochrome c. Examination of neuronal survival revealed that ischemic preconditioning prevents, whereas cycloheximide only delays, ischemic hippocampal CA1 neuronal death. DNA fragmentation detected by terminal deoxytransferase-mediated dUTP-nick end labeling (TUNEL) in situ was largely attenuated by ischemic preconditioning and moderately reduced by cycloheximide. These results indicate that the loss of cytochrome c from mitochondria correlates with hippocampal CA1 neuronal death after transient cerebral ischemia in relation to both caspase-dependent and -independent pathways. The amount of mitochondrial cytochrome c regained may determine whether ischemic hippocampal CA1 neurons survive or succumb to late-phase death.

Animals↗

PubMed2001

Bisoprolol improves survival in rats with heart failure.

The cardioprotective effects of bisoprolol were studied in a rat model of severe heart failure induced by autoimmune myocarditis. Twenty-eight days after immunization, Lewis rats were divided into four groups: 0.1 mg/kg/day bisoprolol (Group 0.1), 1.0 mg/kg/day bisoprolol (Group 1) and 10 mg/kg/day bisoprolol (Group 10), and vehicle (0.5% methylcellulose; Group V) (all groups, n = 13). After oral administration for 1 month, heart weight, mean blood pressure, heart rate, central venous pressure, peak left ventricular pressure, left ventricular end-diastolic pressure, +/- dP/dt, and area of fibrosis were measured. Although bisoprolol reduced heart rate (399+/-11/min in Group V, 382+/-10/min in Group 0.1, 348+/-8/min in Group 1 and 302+/-9/min in Group 10) and increased survival (62% in Group V, 69% in Group 0.1, and 100% in Group 1 and Group 10) in a dose-dependent manner, this drug did not change heart weight, the area of myocardial fibrosis or hemodynamic parameters. These observations suggested that bisoprolol may improve survival independently of its effect on left ventricular function by reducing sudden death in patients with severe heart failure.

Adrenergic beta-Antagonists↗