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Biomedical subjects

K Naitoh

Publications and source records attributed to K Naitoh.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Usefulness of enhanced computed tomography in the diagnosis of pulmonary thromboembolism].

Pulmonary thromboembolism (PTE) was diagnosed in 22 patients at Saga Medical School between 1981 and 1994. Enhanced computed tomography (CT) was done in 8 patients, and filling defects in the central pulmonary artery were identified in 6. Parenchymal shadows (wedge shaped shadows, subpleural consolidation, or nodular shadow's) were noted in 5. When enhanced CT was done during acute severe respiratory failure in 3 patients, pulmonary artery filling defects were found in all. These findings suggest that enhanced CT is useful as a diagnostic tool for acute PTE with respiratory failure. Electron beam CT may be a sensitive and specific means of diagnosing PTE because it can be done quickly and without breath-holding. We conclude that enhanced CT should be used as the first diagnostic procedure in patients with severe respiratory failure who may have PTE.

Adult↗
PubMed1997

[A case of primary mediastinal choriocarcinoma].

A 27-year-old man with primary mediastinal choriocarcinoma was reported. He was admitted with complaint of right chest pain and dyspnea. Chest X-ray film and computed tomography of the chest revealed a bulky mass at anterior mediastinum and right pleural effusion. Physical examination revealed bilateral gynecomastia, and the serum beta-HCG level was cap at 500 ng/ml. The specimens obtained by percutaneous needle biopsy of the mediastinal mass showed cytotrophoblasts and syncytiotrophoblasts. He received 4 cycles of anti-cancer chemotherapy, and underwent resection for a residual mass, in which viable cancer cells remained in histological examination. In spite of additional chemotherapy, multiple lung metastasis developed rapidly. High dose chemotherapy, with carboplatine (200 mg/m2 x 4 days), etoposide (250 mg/m2 x 4 days) and cyclophosphamide (50 mg/kg x 2 days) was performed in combination with peripheral blood stem cell autotransplantation. However, brain metastasis set in and he died of respiratory failure 9 months after the onset of symptoms.

Adult↗
PubMed1996

Effect of physical activity as a caddie on ultrasound measurements of the Os calcis: a cross-sectional comparison.

This cross-sectional study investigated the effect of long-term activity as a caddie on ultrasonic properties of the os calcis. We measured 74 healthy women, age 20-59 years, who worked at a golf course as caddies. An age-matched control group of 433 healthy women, who were office workers or housewives, also were recruited for comparison. The ultrasound measurements were performed with an Achilles ultrasound densitometer. The quadriceps muscle strength and the hand grip strength were measured in a perimenopausal subgroup (45-59 years) of the caddies and a subgroup of controls matched for age, height, weight, and body mass index. Urinary pyridinoline and deoxypyridinoline were also measured in these perimenopausal subgroups. Caddies had significantly higher ultrasound values than controls in the 40-49 (stiffness index, 101.6 +/- 12.9% versus 87.9 +/- 11.9%; p < 0.0001) and 50-59 (stiffness index, 90.5 +/- 11.6% versus 77.2 +/- 11.6%; p < 0.0001) age-stratified groups. Quadriceps strength and grip strength were significantly higher in caddies than those in controls. In postmenopausal caddies, all ultrasound values were significantly higher than for controls. In caddies there were not significant decreases of any ultrasound values with postmenopausal age. Even for the subgroup within 3 years of menopause there were significant differences between caddies and controls (p < 0.01). There were no significant increases of pyridinoline and deoxypyridinoline after menopause in the caddies. We demonstrated that the caddies had higher ultrasound properties of the os calcis and lower bone resorption after menopause compared with controls.

Adult↗
PubMed1996

[Surgery for acute type A aortic dissection associated with Marfan syndrome].

Recently, extended operation has been recommended for aortic dissection associated with Marfan syndrome. However, the operation for acute type A aortic dissection associated with Marfan syndrome is controversial. Between May 1985 and July 1994, 5 patients associated with acute type A aortic dissection and Marfan syndrome underwent surgical repair. CT examination on all patients, the survivors of the initial operation, revealed a gradually enlarged residual pseudolumen. 2 patients who underwent aortic root reconstruction and ascending aortic replacement for the initial operation eventually had to undergo aortic arch repair. From the results of this study and the improvements of intraoperative cerebral protection, we recommend aortic arch repair with aortic root reconstruction and ascending aortic replacement on initial emergency operation for acute type A aortic dissection associated with Marfan syndrome.

Acute Disease↗
PubMed1995

Efficient isolation of mutant antigen presenting cell lines by functional selection using T cell clones.

An efficient method for the isolation of mutant antigen-presenting cell (APC) lines is described. When mixtures of transfectant APC lines TA beta z (that express A beta z/A alpha d MHC class II molecules) and hypothetical variant APC lines TA beta d (that express A beta d/A alpha d class II molecules) were cultured with and selected by autoreactive A beta z/A alpha d-restricted T cell clones, the percentage of TA beta d APC lines increased from less than 1% of the original APC mixtures to almost 100% after several cycles of selection. This increase of hypothetical variant was shown to be due to the formation of aggregates of wild-type TA beta z APC lines with A beta z/A alpha d-restricted autoreactive T cell clones that results in the inhibition of proliferation and probably killing of TA beta z APC lines. Based on this, ethyl methane sulfonate (EMS)-treated TA beta z APC lines or B-B hybridoma APC lines MW4 (that express A beta z/A alpha d and A beta z/A alpha z class II molecules) were cultured with and selected by A beta z/A alpha d-restricted autoreactive T cell clones to obtain mutant APC lines that escaped the recognition by T cell clones. After cloning, about 43% of clones examined lost the ability to stimulate T cell clones with concomitant loss of class II molecule expression. Less than 1% showed loss of stimulatory activity against T cell clones in spite of the expression of normal amounts of class II molecules. Initial analysis revealed that they include APC mutant lines with (1) altered MHC class II sequences, (2) loss of adhesion molecule expression and (3) possible impairment of the peptide loading. The method described here may provide a variety of mutant APC lines that are useful for the analysis of antigen processing and presentation pathways as well as of class II structure for T cell stimulation.

Animals↗
PubMed1995

[Surgical treatment for Stanford type A acute aortic dissection].

From March 1983 to September 1994, 53 consecutive patients underwent an emergency operation for type A acute aortic dissection. Eighteen patients before 1988 (Group I) underwent simple ascending aortic replacement (n = 13) and composite graft replacement (n = 5) by conventional method. Thirty-five patients after 1989 (Group II) underwent extended ascending aortic replacement (n = 17), hemiarch replacement (n = 6), total arch replacement (n = 8) and composite graft replacement (n = 4) using a brief period of circulatory arrest. The overall hospital mortality rate was 36.8% in Group I and 25.7% in Group II. The survivals after initial operation was 47% at 10 years (Kaplan-Meier) and the event free rate was 78% at ten years, respectively. Computed tomographic scanning and aortogram demonstrated the patent false lumen in 20 patients (64.5%) at the descending thoracic aorta. In conclusion, extended ascending aortic replacement is the useful operative technique to perform accurate resection of intimal disruption and clamp-site aorta because the replacement of the entry site could reduce the risk of operative mortality and reoperation. Total arch replacement is not necessarily required, if the entry is properly resected by extended ascending aortic replacement or hemiarch replacement. Close follow-up must be considered at the patients with patent false lumen, especially in patient with Marfan's syndrome.

Acute Disease↗
PubMed1994

Signal transmission through MHC class II molecules in a human B lymphoid progenitor cell line: different signaling pathways depending on the maturational stages of B cells.

The function of MHC class II HLA-DR molecules expressed on a human B lymphoid progenitor cell line FL8.2.4.4 (abbreviated as FL4.4) was examined. FL4.4 cells expressed HLA-DR molecules and stimulation of the DR molecules by anti-DR mAb or by superantigen TSST-1 induced strong augmentation of homocytic aggregation and protein tyrosine phosphorylation in FL4.4 cells. Induced homocytic aggregation in FL4.4 consists both of LFA-1/ICAM-1-dependent and -independent pathways as revealed by mAb blocking experiments. Metabolic inhibitors, NaN3 and cytochalasin B, blocked the induced homocytic aggregation of FL4.4. Early mature Daudi B cell lines also showed a similar type of homocytic aggregation by stimulation with anti-DR mAb. Daudi cells are more sensitive to protein kinase inhibitors herbimycin A and H7 than FL4.4 cells in their blocking of induced homocytic aggregation, while W7 showed stronger inhibitory effects on FL4.4 cells than on Daudi cells. Western blotting analysis revealed that the stimulation of DR molecules induced protein tyrosine phosphorylation of 100-kDa, 90-kDa, 60-kDa and 55-kDa proteins in FL4.4 cells, while, in Daudi cells 110-kDa, 100-kDa and 80-kDa proteins were phosphorylated. These results suggest that different signaling pathways through class II molecules are employed depending on the maturational stage of B-cell differentiation.

Antibodies, Monoclonal↗
PubMed1994

Acute, subchronic and chronic toxicity studies of a synthetic antioxidant, 2,2'-methylenebis(4-methyl-6-tert-butylphenol) in rats.

General toxicity studies on 2,2'-methylenebis(4-methyl-6-tert-butylphenol) (MBMBP) were conducted using male and female Wistar rats. LD50 values were greater than 5 g/kg BW by oral administration for both sexes. Diarrhea was observed until 5 days. In the subchronic test, rats were fed diet containing MBMBP at 0, 0.12, 0.6 or 3.0% for 12 weeks. Severe suppression of body weight gain was observed in both sexes of 0.6 and 3.0% groups. Death accompanied by hemorrhage from nasal cavity was observed in 0.6 and 3.0% males and 3.0% females. Dose-dependent toxicity to the liver in both sexes was observed in blood chemical analysis. Histopathologically, testicular atrophy and decrease of spermatogenesis were dose- and time-dependently observed in all treated males. Atrophy of ovaries was evident in 0.6 and 3.0% females. Thymus atrophy and bone marrow hypoplasia were observed in both sexes of 0.6 and 3.0% groups. In the chronic test, rats were fed diet containing MBMBP at 0, 0.01, 0.03 and 0.1% for 18 months. Body weight gain was only suppressed in both sexes receiving 0.1%. Histopathologically, testicular atrophy and decrease of spermatogenesis were apparent in 0.1% males. No neoplastic response by MBMBP administration was noted. NOAEL was concluded to be 0.03% in the diet (12.7 mg/kg BW/day for male rats and 15.1 mg/kg BW/day for female rats).

Administration, Oral↗
PubMed1994

Protection against spinal cord ischaemia: one-shot infusion of hypothermic solution.

The protective effect of a one-short infusion of a range of low-temperature hypothermic solutions against spinal cord ischaemia was investigated. Forty rabbits were allocated into five groups each of eight animals. The abdominal aorta of each rabbit was clamped distal to the left renal artery, and also occluded for 30 min above the iliac bifurcation with an inflated 50-gauge French balloon catheter. Ringer's solution with lactate was infused through the catheter port distal to the balloon, at various temperatures (group I, uninfused control; group II, 33 degrees C; group III, 23 degrees C; group IV, 13 degrees C; and group V, 3 degrees C). The neurological status of the hind limbs was assessed on the second postoperative day using the criteria of Tarlov. A further eight rabbits underwent laminectomy at L2 or L3. Temperature probes were inserted into the spinal cord and the cord temperature monitored continuously during infusion in four rabbits from each of groups I and V. Spastic paraplegia occurred in five rabbits in group I, three in group II, and two in group III. Four rabbits in groups II and III, seven in group IV and all eight in group V showed complete recovery of neurological function. The infusion of 3 degrees C solution achieved significantly lower spinal cord temperatures in group V after aortic clamping, compared with the temperatures in group I (P < 0.001-0.005). It was concluded that protection against spinal cord ischaemia and prevention of postoperative paraplegia are promoted as the temperature of the hypothermic infusion solution is lowered.

Animals↗
PubMed1994

[Successful mitral valve replacement in multiple organ failure due to mechanical hemolytic anemia after mitral valve repair: a case report].

An 18-year-old man suffered multiple organ failure due to hemolytic anemia after mitral valve repair. He was admitted with mitral regurgitation (MR) and mitral valve repair was performed. However, after 3 days of the operation, he developed hemolytic anemia and heart murmur. A reoperation of mitral valve replacement was performed because of progressing heart failure with renal and liver dysfunction. The operative findings revealed a rupture in the choldae with dislocation of the C-E ring. The MR flow and dislocated ring are suspected to be the cause of the hemolysis. After the reoperation, the hemolysis and general condition were immediately improved. The indication of this reoperation should be carefully decided. In this case of multiple organ failure following mitral valve repair, reoperation of mitral valve replacement was successful.

Adolescent↗
PubMed1994

[A surgical treatment of ruptured arch aneurysm].

A 83-year-old woman was admitted to our hospital because of back pain and shock. Her chest X-ray and CT scan demonstrated a large arch aneurysm and hemothorax, suggesting ruptured aortic arch aneurysm. The ruptured aortic arch aneurysm was replaced with a woven Dacron graft under selective cerebral perfusion (SCP). Her postoperative course was uneventful without any neurological deficits. For the past three years, we have utilized SCP in 12 cases of arch aneurysms. There were three early deaths in this series. The cause of death were bleeding in one patient and cerebral accident in two patients. The latter two patients had severe atheromatous changes in the aortic wall. The SCP technique was a useful method of cerebral protection, especially for elderly patient with aortic arch aneurysm.

Aged↗
PubMed1993

Generation of cells with morphological and antigenic properties of microglia from cloned EBV-transformed lymphoid progenitor cells derived from human fetal liver.

Single-cell clones from the Epstein Barr virus transformed lymphoid progenitor-like cell line established from human fetal liver at 8-week gestation, have been derived and characterized. These clones retained immunoglobulin (Ig) and T cell receptor (TCR) genes in their germ line configuration. They expressed HLA-DR and some B lymphoid markers such as CD19, CD20, and in some, the T lymphoid marker, CD2. They did not express surface Igs, CD3, CD4, CD8 or TCRs (alpha/beta, gamma/delta). A sensitive RT-PCR assay revealed that they did not express mRNA for a recombination activating gene-1, which is expressed after commitment to lymphoid cells. These results suggest that the established cloned lines are very early lymphoid progenitors that have not yet been committed to lymphoid cell lineage. In one of the lines, FL8.2.1.4, a marked morphological change that resembled microglia was induced when the cells were cultured in the presence of phorbol myristate acetate (PMA). After 72 hr of culture, 5-10% of FL8.2.1.4 cells developed a microglial morphology when stimulated with 10 to 100 ng/ml PMA. The newly generated cells with microglial morphology expressed HLA-DR and stained with Recinus communis agglutinin-1, which has been reported to bind specifically to brain microglia. In contrast, expression of lymphoid markers on cells with microglia-shaped morphology was remarkably diminished by PMA stimulation. Thus, the early lymphoid progenitor cells have the capacity to differentiate into cells with the morphological and antigenic properties of microglia cells. This system might be useful for further understanding of the characteristics and functions of microglia cells distributed in the central nerve system.

Antigens, CD↗
PubMed1992

Serum estradiol 17-sulphate and lipid peroxides in late pregnancy.

Estradiol 17-sulphate is readily converted to 2-OH or 4-OH estradiol 17-sulphate. The latter two strongly antagonize lipid peroxidation, which may play certain roles during pregnancy, such as pregnancy-induced hypertension. Serum estradiol 17-sulphate during mid and late pregnancy was measured using a direct radioimmunoassay without hydrolysis, and the level increased as pregnancy progressed. The levels in the sixth (20-23 weeks) and tenth months (36-39 weeks) of gestation were 1.42 +/- 0.04 nmol/l (mean +/- SD) and 3.42 +/- 1.09 nmol/l, respectively. The maternal venous levels before and at delivery and in the umbilical veins and artery were 3.38 +/- 0.83, 3.48 +/- 1.53, 4.11 +/- 1.40 and 4.30 +/- 1.81 nmol/l, respectively. The latter two values were slightly higher than the former two. Estradiol 17-sulphate in maternal venous blood began to decrease around delivery. Serum lipid peroxides were measured using the method of Yagi. Estradiol 17-sulphate and lipid peroxides showed a simple regression slope (r = -0.548, p less than 0.05) during late pregnancy. These results suggest that estradiol 17-sulphate may be converted to 2-OH or 4-OH estradiol 17-sulphate, which act as lipid peroxide scavengers during pregnancy.

Estradiol↗
PubMed1992

Toxicity studies of a synthetic antioxidant, 2,2'-methylenebis (4-ethyl-6-tert-butylphenol) in rats. 1. Acute and subchronic toxicity.

The acute and subchronic toxicity studies on 2,2'-methylenebis (4-ethyl-6-tert-butylphenol) (MBEBP) were conducted using male and female Wistar rats. In acute toxicity test, the LD50 values were estimated to be greater than 10 g/kg BW by oral and intraperitoneal administration in each sex. In subchronic toxicity test, groups of 10 rats of each sex were fed a diet containing 0.2, 1.0 or 5.0% of MBEBP and examined at 4 and 12 weeks. Body weight gain was significantly depressed at doses of 1.0 and 5.0% in both sexes, but the depression in the 1.0% group was severer than that in the 5.0% group in males. Hematological analysis showed slight but significant decrease of hemoglobin in the 1.0 and 5.0% groups of both sexes. Urine analysis showed no remarkable changes in all treated rats of both sexes. In biochemical analysis of serum, decrease of triglyceride level and cholinesterase activity, and increase of amylase activity were observed in treated rats. Histopathologically, testicular atrophy and decrease of spermatogenesis were observed in male rats fed 1.0 or 5.0% MBEBP for 4 and 12 weeks and vacuolization of parathyroid gland cells was observed in female rats fed 1.0 and 5.0% MBEBP for 12 weeks. In subchronic test, the lowest observable adverse effect levels for MBEBP toxicity were estimated to be 171 mg/kg BW/day in male rats and 180 mg/kg BW/day in female rats.

Administration, Oral↗
PubMed1992

Increased interleukin-6 activity in cardiac myxoma with mediastinal lymphadenopathy.

We report a case of cardiac myxoma with mediastinal lymphadenopathy which seems to be a very rare feature. Laboratory examination revealed high level of interleukin-6 (IL-6) activity in serum. Interestingly, after removal of cardiac myxoma, mediastinal lymphadenopathy disappeared on the chest CT and the level of serum IL-6 was decreased. These findings suggest that IL-6 which was probably derived from myxoma, may have played an important role in the development of lymphadenopathy.

Female↗
PubMed1991

Successful combined operation for Takayasu's arteritis.

We report a case of Takayasu's arteritis complicated with aortic regurgitation and severe stenosis of the left coronary ostium and the innominate artery. Simultaneous surgical treatment of aortic valve replacement, coronary ostium endarterectomy, and aortosubclavian artery bypass using saphenous vein were performed. We discuss the choice of simultaneous operation and the option of surgical treatment for coronary ostium lesion due to Takayasu's arteritis.

Aortic Valve Insufficiency↗
PubMed1991

[Concentration of nitrosodimethylamine in commercial pelleted experimental animal diets].

To know the conditions of contamination by the chemicals in the experimental animal diets, the contents of nitrosodimethylamine (NDMA) were analyzed in the diets for mice and rats. The raw materials of the diets were also analyzed. In addition, NDMA levels were determined in the diets which were stored long or heated in the autoclaves. The averages of NDMA in these diets were less than 10 ppb. In the raw materials, alfalfa contained a higher levels of NDMA. There was no clear tendency of increase or decrease in NDMA levels, when the diets were stored for six months at room temperature (23-25 degrees C) or at low temperature (7-10 degrees C). Heating the diets at 121 degrees C, no remarkable changes were observed in NDMA levels. It seems that little adverse influences on the conduct of the animal experiments would be anticipated by the NDMA in the commercial diets.

Animal Feed↗