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Biomedical subjects

K Ono

Publications and source records attributed to K Ono.

At least 721 records · Page 40Linked to original sources
PubMed1992

Gamma-aminobutyric acid immunoreactivity in the enterochromaffin cells of the rat stomach.

The present immunocytochemical study revealed gamma-aminobutyric acid (GABA) immunoreactivity in the oxyntic and pyloric mucosa of the rat stomach at light- and electron-microscopic levels. GABA-immunoreactive endocrine cells were numerously seen in the lower half portion of the pyloric mucosa but rarely in the oxyntic mucosa. These cells were round or oval in shape and sometimes had a short cytoplasmic process. Serotonin-immunoreactive enterochromaffin (EC) cells were also observed in the oxyntic and pyloric mucosa of the stomach. The distribution and shapes of the immunoreactive cells were similar to those of the GABA-immunoreactive cells. With a double immunolabeling technique using anti-GABA and antiserotonin serum, GABA-immunoreactive endocrine cells showed serotonin immunoreactivity and were identified as EC cells. At the electron-microscopic level the GABA-immunoreactive cells contained round or oval, spindle-like, pear-shaped granules in EC cells. The immunoreaction product in the EC cells was generally confined to the granular cores. These findings suggest that GABA may be synthesized in the EC cells and be released from the granules of the cells after adequate stimuli.

Animals↗
PubMed1992

Synthesis and anti-human immunodeficiency virus type 1 (HIV-1) activity of 3-substituted derivatives of 3'-azido-3'-deoxythymidine (AZT), and inhibition of HIV-1 reverse transcriptase by their 5'-triphosphates.

Various 3-substituted 3'-azido-3'-deoxythymidine analogs (2a-i) were prepared by the reaction of 3'-azido-3'-deoxythymidine (1), AZT with N,N-dimethylformamide dialkylacetal or alkyl bromide in the presence of base and their activities against human-immunodeficiency virus type-1 (HIV-1) were evaluated. The corresponding 5'-triphosphate analogs (9) were also synthesized in order to examine inhibition of HIV-1 reverse transcriptase activity. Beyond expectation, some N3-derivatives of AZT were found to reserve the anti-HIV-1 activity to some extent. Among the compounds (2a-i) obtained, 3-allyl-AZT (2e) was the most active against HIV-1 replication in MT-4 cells in vitro with an EC50 value of 0.9 microM. 3-Allyl-AZT 5'-triphosphate (9e), however, exhibited no inhibition of HIV-1 reverse transcriptase activity.

Antiviral Agents↗
PubMed1992

Changes of splenic lymphocyte subpopulation in mice inoculated with Babesia microti and Babesia rodhaini.

Changes of splenic lymphocyte subpopulation after Babesia microti and Babesia rodhaini inoculation in mice were examined by flow cytometric analysis. The B. microti inoculated mice showed a longer period of time from inoculation to the onset of increase or decrease parasitaemia (%), packed cell volume, total spleen cell numbers and surface immunoglobulin positive splenic cell numbers than respective periods in B. rodhaini inoculated mice. The Thy-1 positive cell numbers in B. microti inoculated mice and B. rodhaini inoculated mice pre-immunized with homologous parasites were significantly higher than that of B. rodhaini inoculated mice. The ratio of L3T4 positive cell/Lyt-2 positive cell after inoculation with B. microti was quite similar to that in B. rodhaini mice pre-immunized. However, the ratio in B. rodhaini inoculated mice revealed a lack of an increasing phase. These results suggested that the T-cell dependent early immune response, especially suppressor activity, was closely related to the difference in the course of infection between the non-lethal B. microti and the lethal B. rodhaini infection in mice.

Animals↗
PubMed1992

Ossification of the ligamentum flavum induced by bone morphogenetic protein. An experimental study in mice.

Ossification of the ligamentum flavum and secondary spinal-cord compression were produced experimentally in mice by implanting bone morphogenetic protein (BMP) in the lumbar extradural space. The ligamentum flavum became hypertrophied and ossified, and protruded into the spinal canal. The thickness of the ossified ligament increased gradually with time, leading to compression and deformation of the spinal cord which showed various degrees of degeneration. Demyelination occurred in the posterior and lateral white columns and neuronal loss or chromatolysis in the grey matter. The pathological findings in the experimental animals closely resemble those found in the human disease and suggest that BMP may be a causative factor of ossification of the ligamentum flavum in man. This experimental model may be useful for the study of myelopathy caused by gradual spinal-cord compression.

Animals↗
PubMed1992

Calcium hydroxyapatite ceramic used as a delivery system for antibiotics.

Porous blocks of calcium hydroxyapatite ceramic were evaluated as delivery systems for the sustained release of antibiotics. We tested gentamicin sulphate, cefoperazone sodium, and flomoxef sodium in powder form placed in a cylindrical cavity in calcium hydroxyapatite blocks, using in vitro studies of elution and in vivo studies in rats. Gentamicin sulphate gave a maximum concentration within the first week, which gradually decreased but was still effective at 12 weeks, when 70% of the antibiotic had been released. Even at this stage the antibiotic concentration from a 75 mg dose was five times the minimum inhibitory concentration for staphylococci. In the in vivo studies the release of gentamicin sulphate into the normal bone of rats was at similar rates and levels. The bacteriocidal activity of the drugs was not affected by packing into calcium hydroxyapatite ceramic and the blocks were completely biocompatible on histology. This new system overcomes the disadvantages of other drug delivery systems, avoiding thermal damage to the antibiotics and a second operation for the removal of the carrier. Some mechanical strength is provided by the ceramic and healing may be accelerated by bone ingrowth into its micropores.

Animals↗
PubMed1992

Ehlers-Danlos syndrome with soft-tissue contractures.

We report four patients with a form of Ehlers-Danlos syndrome associated with soft-tissue contractures from birth and skin hyperalgesia. In early infancy, these cases were thought to be forms of arthrogryposis multiplex congenita, Larsen's syndrome or Marfan's syndrome. The characteristic triad of signs of Ehlers-Danlos disease gradually appeared from four to six years of age, allowing us to establish the correct diagnosis. We discuss the differential diagnosis of these connective-tissue disorders and the problems of the orthopaedic treatment of the associated joint deformities. Ehlers-Danlos syndrome is a heterogeneous group of metabolic diseases of collagen and our cases constitute a group which is distinct from the conventional types.

Adult↗
PubMed1992

Immunological study of the association between hepatocyte damage and HBc antigen.

To identify the target antigen during hepatocyte damage in hepatitis type B virus (HBV) infections, the expression of HBc and HBs antigens, and beta 2-microglobulin (BMG) were studied in liver tissue. Serial changes of serum DNA-polymerase (DNA-P) activity and HBV DNA were also measured. After the onset of acute hepatitis, HBs antigen in liver tissues was observed from many patients; but HBc antigen was rarely detected. In liver tissues of patients with chronic hepatitis, HBs antigen was consistently positive, irrespective of the changes in sGPT. On the other hand, HBc antigen was frequently positive both preceding and during the culmination period for sGPT. The distribution of HBc antigen in the hepatocyte was mostly cytoplasmic. During the same period the serum DNA-P and HBV DNA were frequently positive. Immunoelectron microscopy showed that reaction products with HBc antigen existed in the cytoplasm and the cell membrane. These results indicate that HBc antigens become the target, when HBV infected hepatocytes are eliminated.

DNA, Viral↗
PubMed1992

[Percutaneous transabdominal whole layer core needle biopsy for staging the urinary bladder cancer].

Accurate staging is one of the most important determinants necessary in planning an effective treatment for bladder cancer, but at the present time, staging by the conventional clinical methods are not completely reliable. Accordingly, we have newly developed a percutaneous transabdominal core needle biopsy technique capable of obtaining good cylindrical specimens of the entire layer. In order to obtain the core specimen of the bladder wall, which is a vesico-elastic material, the biopsy needle must penetrate the bladder wall at an extremely high speed. We have developed an original automatic biopsy instrument and modified the head of needle for this purpose. With this method, we could obtain good core specimens for pathological staging in about 90% cases. The correlation between the pathological stagings of core specimens and those of cystectomy specimens were in good agreement. This technique is accurate not only for preoperative pathological staging, but also monitoring histopathologically the responsiveness of multi-disciplinary treatment for invasive bladder cancer. This method allows us to determine the optimal therapeutic modality for managing individual patient with invasive bladder cancer.

Aged↗
PubMed1992

[Analysis of pedestrian injuries in traffic accidents: impact point, injury portion, and injury severity].

We conducted in-depth case studies of traffic accidents involving 118 pedestrians, who were struck by the fronts of bonnet-type cars. The data were reviewed in order to correlate injury severity with pedestrian age, and area of body contact, contact surface of vehicle or the local environment, and impact speed. It was found that head injuries caused by impacts against the top surface of car bonnets and leg injuries caused by front bumpers both showed high incidence rates. Both head and leg injuries caused by striking the vehicle were more severe than those caused by striking the road surface. In cases of impact between the head and the solid portion of the vehicle, such as the A-pillar, or in cases of secondary impact between the head and underhood solid structures such as shock tower, injuries tended to be more severe. The location of head impact varied according to the stature of the pedestrians.

Accidents, Traffic↗
PubMed1992

The role of T cells in pathogenesis and protective immunity to murine malaria.

T-cell-mediated immunity to a virulent strain of Plasmodium berghei NK65 (Pb NK65) and to an attenuated derivative (Pb XAT) of the strain were examined in CBA mice by the administration of monoclonal antibodies against T-cell subsets or interferon-gamma (IFN-gamma). The injection of anti-CD8+ or anti-IFN-gamma delayed the mortality of mice infected with Pb NK65, although it did not affect the parasitaemia. In the late stage of PB NK65 infection, T cells, especially CD8+ T cells, were increased in number in the liver at the expense of splenic CD8+ T cells. These CD8+ T cells released IFN-gamma in culture without antigen stimulation and were thought to induce tumour necrosis factor-alpha (TNF-alpha) production by the cells in the liver. In mice infected with Pb XAT, or mice primed with Pb XAT and then challenged with Pb NK65, CD4+ T cells had a crucial role in preventing parasite growth and in protective immunity. IFN-gamma was again the key molecule in protective immunity. These results suggest that T cells stimulated with malaria antigen play important roles both in protective immunity and pathogenesis depending upon their subsets; CD8+ T cells in pathogenesis, and CD4+ T cells in protective immunity. These apparently contradictory responses may be mediated by the same cytokine, IFN-gamma.

Animals↗
PubMed1992

Distribution of efferent neurons projecting to the tectum and cerebellum in the rat prepositus hypoglossi nucleus.

Distributions of efferent neurons projecting to the superior colliculus (SC), the pretectum, and the cerebellar cortex were studied in the rat prepositus hypoglossi nucleus (PRH) by retrograde labeling with wheat germ agglutinin-horseradish peroxidase (WGA-HRP). After injection of the tracer into the unilateral SC, small- and medium-sized neurons were labeled throughout the entire rostrocaudal extent of the PRH, with the highest proportion in the middle part of the nucleus. After application of WGA-HRP to the unilateral pretectal region, including the nucleus of the optic tract, numerous labeled neurons appeared in the bilateral PRH. The highest distribution was found in the most rostral part of this nucleus. Furthermore, small neurons of the supragenual nucleus of the facial nerve also were labeled. Injection of WGA-HRP into lobules VI-VII of the cerebellar vermis resulted in the labeling of mainly medium-sized neurons in the bilateral PRH, primarily in the caudal third. WGA-HRP-labeled neurons were less frequently observed in the PRH after unilateral injection into the flocculus and paraflocculus. Retrograde double labeling by fluorescent dyes showed that a few neurons in the middle part of the PRH sent divergent axons to vermal lobules VI-VII and the SC.

Amidines↗
PubMed1992

Efficacy of alumina ceramic heads for cemented total hip arthroplasty.

Fifty-seven cemented total hip arthroplasties (THAs) were reviewed in cases of osteoarthrosis secondary to congenital dysplasia or dislocation. The bearing surface of the prosthesis used in this series consists of a polyethylene acetabular component on an alumina ceramic head. All acetabular components were positioned at the same level as the original acetabulum, and an autologous femoral head graft was performed for 18 hips. The follow-up period ranged from five to eight years, averaging six years two months. The latest survey showed excellent and good results for 53 hips (92.9%). Four acetabular components (7%) and two femoral components (3.5%) showed roentgenographic evidence of loosening. Only one hip (1.8%) had to be treated with revision surgery for femoral component loosening. None of the cases suffered a broken ceramic head. The use of a total hip prosthesis with an alumina ceramic head in THA is likely to lead to excellent results for patients with osteoarthrosis of the hip.

Adult↗
PubMed1992

Is folate supplementation necessary in hemodialysis patients on erythropoietin therapy.

The need for folate supplementation in hemodialysis (HD) patients receiving erythropoietin (EPO) therapy remains unknown. Twenty stable HD patients, taking folic acid, 5 mg, after a meal during each HD session were divided into two groups. Supplementation was withdrawn at the start of the study in group 1 and after a 12-month-observation period in group 2. EPO treatment, 1500 u x 3/week i.v. was started in both groups. Pre- and post-HD blood samples were obtained at the beginning of the study for baseline values, then 12 and 18 months later. Folate levels decreased to normal after withdrawal of the supplements. The response to EPO treatment was exactly the same in both groups and the anemia was effectively improved. We conclude that there is no need for routine folic acid supplements in HD patients receiving EPO therapy if they are eating an adequate mixed diet.

Erythropoietin↗
PubMed1992

Laminoplasty versus subtotal corpectomy. A comparative study of results in multisegmental cervical spondylotic myelopathy.

A comparative study of surgical results was used to determine the treatment of choice for multisegmental cervical spondylotic myelopathy. Forty-one patients who received subtotal corpectomy and strut grafting (SCS) and forty-two undergoing laminoplasty were followed up for at least 2 years after surgery. Regarding factors known to affect surgical prognosis (age at surgery, duration of symptoms, severity of neurologic deficit, anteroposterior canal diameter, transverse area of the cord at the site of maximum compression, number of levels involved), the two groups were statistically comparable with each other. The severity of neurologic deficits was assessed by the Japanese Orthopaedic Association scale. Results were evaluated in terms of postoperative score and recovery rate. The difference between the recovery rate and final score between the two groups was not statistically significant. Surgical complications were more frequent in the subtotal corpectomy and strut grafting group than in the laminoplasty group. The most frequent complications encountered in the subtotal corpectomy and strut grafting group were related to bone grafting. Spinal alignment worsened in six patients of the laminoplasty group, but none of them suffered from neurologic deterioration. Another disadvantage of subtotal corpectomy and strut grafting was the longer postoperative period of bed rest needed to secure graft stability. We conclude that laminoplasty should be the treatment of choice for multisegmental cervical spondylotic myelopathy when neurologic results, incidence of complications, and postoperative treatment are taken into consideration.

Aged↗