Biomedical subjects

K Ikeuchi

Publications and source records attributed to K Ikeuchi.

At least 37 records · Page 2Linked to original sources

PubMed1999

[A case of urothelial carcinoma associated with penile metastasis].

A 71-year-old man, who had been treated with continuous ambulatory peritoneal dialysis due to chronic renal failure for 5 months, visited our hospital with a complaint of penile induration in April, 1998. He underwent wedge biopsy of the penis. On the day after the biopsy, he had an episode of gross hematuria. Cystoscopy revealed a papillary tumor that seemed to have arisen from the right ureteral orifice and another in the trigone. Computed tomographic scan revealed the bladder tumors and swelling of the internal iliac lymph nodes. The bladder tumors were resected transurethrally. The pathological diagnosis of the specimen from the penile induration was metastatic transitional cell carcinoma.

Aged↗

PubMed1998

A new method for accurate measurement of displacement of the knee menisci.

It is difficult to measure the displacement of the menisci under external forces by the radiographic method using markers because the movement may be smaller than the detecting limit. A device with a flexible needle attached to a journal of a miniature linear bearing is developed to investigate the meniscal functions which depend on the mobility. The needle tip is fixed to the target point in the meniscus and the axial displacement is measured with a laser sensor. According to the test, the lower limit for detection was 10 microns, the error due to non-linearity was less than 5 per cent and the reactive force was less than 0.15 N in the operating range of +/- 3 mm. Displacement vectors were determined at four points in a pair of menisci in a porcine knee subjected to external forces. This accurate method will lead to further investigation into the mechanical function of the menisci.

Animals↗

PubMed1998

[A case of septic shock following incarceration of the penis].

An 84-year-old male presented to the emergency room with the chief complaint of painful, swollen penis following the use of a constriction ring to maintain penile erection. A high fever, chills and hypotension were recognized. Septic shock was presumed, and administration of antibiotics was started. Microbiologic cultures revealed Escherichia coli in blood. We herein report a rare but serious complication accompanying incarceration of the penis.

Aged↗

PubMed1998

[Giant vesico-vaginal stone: a case report].

A 74-year-old female with the chief complaint of lower abdominal and anal pain had been suffering from total incontinence due to cerebral palsy since her childhood. A giant stone was palpable on vaginal examination. A radiograph showed a giant calcification in the pelvis. Magnetic resonance imaging (MRI) revealed a giant vesico-vaginal stone, which occupied most of the bladder and vagina. Cystolithotomy was performed. The removed stone weighed 435 g, and measured 9.0 x 6.5 x 5.5 cm, and was composed of magnesium ammonium phosphate. To our knowledge only eight cases of female giant vesical stone have been reported. We herein report a rare case of vesico-vaginal stone unrelated to gynecological procedures.

Aged↗

PubMed1998

[Peripelvic extravasation due to peritoneal dissemination of pancreatic carcinoma: a case report].

We herein report a rare case of peripelvic extravasation due to peritoneal dissemination of pancreatic carcinoma. A 75-year-old female with left flank pain was admitted. Computed tomographic scan demonstrated a huge urinoma medial and posterior to the left kidney, and an irregular mass around the left lower ureter. Retrograde pyelography showed complete ureteral obstruction. The probable diagnosis was spontaneous peripelvic extravasation due to left ureteral tumor or ovarian tumor. Laparotomy revealed a tumor involving the body and tail of the pancreas and some disseminated tumors in the retroperitoneum. Pathological diagnosis was metastatic carcinoma of the pancreas. Malignant tumors in the digestive organs should be taken into consideration in the differential diagnosis of peripelvic extravasation.

Adenocarcinoma↗

PubMed1997

Intrapulmonary Mycobacterium avium infection as the first manifestation of chronic granulomatous disease.

A 10-month-old Japanese male infant, with no history of being prone to infections, contracted an intrapulmonary mycobacterial infection. After 2 months of intermittent fever, radiological examinations revealed mass lesions in the lung and mediastinum. Biopsy specimens showed granulomas with caseous necrosis, from which Mycobacterium avium was isolated. There was no history of mycobacteriosis or immunodeficiency diseases among his relatives. Analyses of the O2- release and expression of NADPH oxidase components verified that he suffered from gp91-phox- chronic granulomatous disease (CGD), and that his mother was a carrier of the disease. This is a rare clinical presentation for the onset of CGD, suggesting that the invasive mycobacteriosis might result from defective intracellular killing of CGD-phagocytes.

Granulomatous Disease, Chronic↗

PubMed1996

An observation on subsurface defects of ultra high molecular weight polyethylene due to rolling contact.

Ultra high molecular weight polyethylene (UHMWPE) has been used in artificial joints for a few decades, and wear of UHMWPE has been one of the main problems. Though many other materials have been tested over the years, the best clinical results are still achieved with UHMWPE. This makes the study of UHMWPE, especially in relation to artificial joints, very important. Frequently, more severe wear can be observed in artificial knee joints than in artificial hip joints especially when the flaking-like wear occurs. This flaking-like wear can lead to significant destruction of the artificial knee joint. Macroscopically, artificial knee joints have combinational movements of rolling and sliding in order to simulate the motion of the normal knee joint. The components of motion are separated to make study easier. Fatigue tests of UHMWPE under the rolling contact condition were performed in this study. Three ceramic spheres were rolled over the UHMWPE specimen using 37 degrees C distilled water as a lubricant. The UHMWPE specimen was observed by the scanning acoustic tomography, microscopy, and SEM. Some subsurface defects could be observed by SAT even before experiments. Although the apparent wear is not observed on the surface, there was an increase in the number of observable subsurface cracks in the UHMWPE specimen. This shows that cracks occur under the surface after a 10(7) rolling contact loading, which is very close to the cyclic loading and unloading with very little friction compared to the sliding contact.

Ceramics↗

PubMed1995

Potential parameters of male reproductive toxicity: reproductive performance, histopathology and sperm evaluation in SD rats given nitrazepam.

The present study was designed to elucidate the correlation between findings from reproductive performance testing and those from histopathological examination of the testis and sperm analysis in rats given a benzodiazepine derivative, nitrazepam, for 2 and 4 weeks. The mechanisms of toxicological action of nitrazepam on the male reproductive organs were also investigated. Nitrazepam was given orally to Sprague-Dawley male rats (6-week-old) at a daily dose of 80 mg/kg for 2 weeks or at daily doses of 20, 40 or 80 mg/kg for 4 weeks. Treated males were mated to examine reproductive performance with untreated females after each dosing period, and after 4 and 9 week of recovery periods. Necropsy was performed for histopathological examination of the testis and epididymis and for sperm analysis after each dosing period and the final mating trial (total of 11 weeks recovery). In the findings from reproductive performance testing, significant decrease in the fertility index was observed in the 80 mg/kg group even after 2 weeks dosing and thereafter until 4 weeks recovery, though the mating index did not significantly differ from that of controls through the experiment. In the histopathological examination and sperm analysis, testicular signs of toxicity, decrease in number of sperm heads in the testis and increase in number of sperm with abnormal heads in the seminiferous tubules were noted in the 80 mg/kg group after 2 weeks dosing and in the 40 and 80 mg/kg groups after 4 weeks dosing. Concentrations of plasma testosterone and content of testis testosterone in nitrazepam-treated groups were not significantly different from those of controls. Plasma FSH concentration was significantly elevated in the 80 mg/kg group through the experiment, although significant elevation of plasma LH was observed only after 2 weeks dosing. These results indicate that histopathological examination is the most reliable approach to detect male reproductive adverse effects induced by nitrazepam rather than using parameters from mating trials. The four-week-dosing period is appropriate for their detection. Hypospermatogenesis induced by nitrazepam is suggested to be caused by direct action of nitrazepam on germ cells and/or Sertoli cells rather than by indirect action through inhibition of testosterone secretion.

Animals↗

PubMed1995

[Spontaneous rupture of ureter caused by ureteral cancer].

A 63-year-old man was admitted with right flank pain, nausea and chill. CT scan revealed right hydronephrosis and rupture of ureter, but tumor or stone was not detected in the CT scan. However retrogradepylelography revealed right lower ureteral tumor, and this patient was treated by right nephroureterectomy and partial cystectomy. Histopathological examination of ureteral tumor showed transitional cell carcinoma. Spontaneous rupture of ureter due to ureteral cancer is a rare case, which has not been reported in the Japanese literature. Clinical study was performed about cases of spontaneous rupture of ureter which have been previously reported.

Carcinoma, Transitional Cell↗

PubMed1995

[A case of huge prostate cancer].

An 89-year-old man with bilateral leg edema and a huge abdominal mass was admitted for further evaluation. CT scan showed a hugh prostatic mass which occupied the whole pelvis cavity accompanying multiple pelvic bone metastases. Suprapubic needle biopsy revealed that the mass was well differentiated adenocarcinoma of prostate origin. The treatment was initiated by 500 mg per day of estramustine phosphate combined with injectable LH-RH analogue 2 months later. The serum levels of tumor markers were markedly elevated at the first visit; PSA 210ng/ml, PAP 110ng/ml, gamma-Sm 800ng/ml. They became normalized 3 months after the initiation of the treatment, and the mass was reduced to 11.5% of the initial size, which lead to removal of indwelling urethral catheter. The patient and his family, however, refused further treatment and the patient died of disseminated disease 8 months later.

Adenocarcinoma↗

PubMed1994

Biomaterials lubricated for minimum frictional resistance.

To improve the frictional characteristics of a biomaterial, the mechanical performance of a lubricated surface was studied. In vitro friction tests showed that the coefficient of dynamic friction of the lubricated surface was about 0.01 against rabbit bladder and the coefficient of static friction increased with the preload period. The efficacy of a lubricated cystoscope was evaluated by an in vivo test simulating cystoscope operation. The maximal and the total resistance force on the cystoscope model were found to decrease with the surface lubrication. Histological study revealed that urethral damage caused by rubbing with the cystoscope model was reduced by this lubrication technique. Presumably, prolonged retention of water on the lubricated surface region prevented tissue adhesion to the foreign material.

Animals↗

PubMed1994

[The usefulness of hormonal therapy in the treatment of prostatic cancer--clinical analysis of 160 cases over 12 years in the single institute].

At the Second Tokyo National Hospital, treatment of patients with prostatic cancer was carried out under the same protocol over 12 years. The mean age of the patients was 73.6 years, and 50% of them fell into the Stage D category. As the initial treatment, hormonal therapy consisting primarily of diethylstilbestrol diphosphate (DES-P) was given to 93.8% of the patients, and the effectiveness of the initial treatment was observed in 87.4% of them. The pre-treatment tumor marker value was high in 65.6% of the patients, and reverted to within normal limits after treatment in 51.3% of them. Relapse was observed in 15.0% of the patients. Side effects of hormonal therapy were observed in 20.7% of the patients, and the side effects resulted in death in 1.3% of them. Throughout the duration of the study, 34.4% of the patients resulted in death; 18.8% of these deaths related to cancer and 13.1% of them to other causes. The 5-year survival rate of all patients was 68.1%, and the 10-year survival rate was 52.7%. DES-P which is the primary drug in the protocol employed at our institution was well tolerated in the patients with minimal side effects when given appropriately and was believed to be an extremely effective drug in the treatment of prostatic cancer in Japan.

Age Factors↗

PubMed1994

Effects of cross-sectional stress-relaxation on handling characteristics of suture materials.

Pullout friction and cross-sectional relaxation tests were conducted to quantitatively evaluate the handling characteristics of braided suture. The excellent handling of silk suture could be explained in terms of a large difference between static and dynamic pullout resistances. The difference in the resistance was closely correlated to the slope of the cross-sectional relaxation versus time logarithmic plot. It was therefore concluded that the cross-sectional stress-relaxation plays an important role in the handling performance of braided sutures.

Insect Proteins↗

PubMed1993

Handling characteristics of braided suture materials for tight tying.

To establish criteria for characterizing synthetic sutures, the handling characteristics of silk suture were analyzed. The characteristics that distinguish silk suture from other braided suture materials are its good "knot security" and relatively low "tiedown resistance." Analytic consideration of knot security suggests that not only superficial friction but also resistance force produced by cross-sectional deformity of braided threads plays an important role in silk's superior performance. Results of a "pullout friction test," developed to quantitatively evaluate resistance produced by surface friction and cross-sectional deformity suggest that the superiority of silk thread can be explained in terms of high static withdrawal resistance under low loads and relatively low dynamic withdrawal resistance under high loads.

Elasticity↗

PubMed1992

A study on elongation and knot slacking of various sutures.

The tension holding capacity of suture materials was measured by in vitro and in vivo experiments. Silk and expanded polytetrafluoroethylene sutures showed large elongation and significant knot slacking after tight tying. Although ultrahigh molecular-weight polyethylene suture had excellent creep resistance, it showed a relatively low tension holding capacity because of substantial knot slacking. On the other hand, polyester and high-strength poly(vinyl alcohol) sutures showed an excellent in vivo tension holding capacity, along with low elongation and insignificant knot slacking. Clinical performance of these sutures was briefly discussed from the mechanical point of view.

Elasticity↗

PubMed1991

Low wear rate of UHMWPE against zirconia ceramic (Y-PSZ) in comparison to alumina ceramic and SUS 316L alloy.

Partially stabilized zirconia ceramic is being recognized among ceramics for its high strength and toughness. With this ceramic, is possible to manufacture a 22-mm-size femoral head for low friction arthroplasty of the hip joint in association with an ultra-high-molecular-weight polyethylene socket. Wear-resistant properties of zirconia ceramic were screened on two principally different wear devices. Sterile calf bovine serum, physiological saline, and distilled water were chosen as the lubricant fluid media. Depending on the lubricant medium, the wear factor of polyethylene against zirconia ceramic counterfaces was 40 to 60% less than that against alumina ceramic counterfaces, and 5 to 10 times lower than with the SUS316L metal counterfaces. Polyethylene wear against metal was more susceptible in saline in which it had 2 to 3 times higher wear rate than with serum. On the other hand, different fluid media had little effect on polyethylene wear against ceramic counterfaces. In each set of tests, the wear factor obtained on an unidirectional wear device showed 10 to 15 times higher values, in comparison to the wear factor estimated on a reciprocating wear device.

Alloys↗

PubMed1991

Characterization of autoantibodies to the CD4 molecule in human immunodeficiency virus infection.

Autoantibodies to the CD4 protein, which serves as a receptor for the human immunodeficiency virus (HIV) on the surface of target cells, were found in patients with different stages of HIV disease. Using recombinant soluble CD4 (rCD4) antigen in a enzyme-linked immunosorbent assay (ELISA), we detected serum anti-CD4 antibodies in approximately 20% of HIV-1 infected patients and 13% of HIV-2 infected patients. There was no correlation between the presence of anti-CD4 antibodies and the stage of HIV disease, serum IgG concentration, number of peripheral blood CD4 positive lymphocytes, or CD4/CD8 lymphocyte ratios in HIV-1 infected patients. Immunoaffinity purified anti-CD4 antibody failed to bind to CD4 positive cells using flow cytometric analysis. However, this antibody could weakly bind to CD4 positive cells that had been preincubated with purified recombinant gp120 (rgp120). In addition, using an ELISA system, we found that the binding of purified patient anti-CD4 antibody to rCD4 was increased in the presence of rgp120. Similar increased binding was observed with the anti-CD4 monoclonal antibody OKT4, but not with anti-Leu3a. These data suggest that a conformational change in the C-terminal domains of CD4 may be induced by gp120 binding and could lead to development of anti-CD4 antibodies.

Autoantibodies↗

PubMed1991

Augmentation of anti-tumor effect of interleukin 2 with sizofiran in mice.

Augmentation of anti-tumor effect of interleukin 2 (IL-2) with sizofiran (SPG) was demonstrated with in vivo and in vitro experiments. C3H/He mice with subcutaneously inoculated X5563 tumor were used as experimental models. IL-2 at a dose of 2 X 10(4) units per mouse by subcutaneous injection, and/or SPG at a dose of 0.1 g per mouse by intramuscular injection were given every other day for a total of ten times. Tumor infiltrating lymphocytes (TIL) were investigated with the avidin-biotin peroxidase complex method. Cytotoxic activity of mice spleen cells after the therapies against YAC-1, X5563 and MH134 were tested with 51Cr release assay. IL-2 or SPG alone suppressed tumor growth in vivo, although not significantly. Combination therapy with IL-2 and SPG suppressed tumor growth in vivo significantly (p = 0.04). Mice treated with the combination survived longer than the mice treated with the single drug (p less than 0.05) and the controls (p less than 0.001). Immunohistologically, more TILs were seen in the combination group than the other groups. In the cytotoxicity study, 3 days after initiation of the therapies, augmentation of natural killer (NK) activity was greater by the combination than by IL-2 or SPG alone. After incubation with IL-2, the spleen cells from mice treated with the combination showed higher cytotoxicity against X5563 or MH134 tumors than those treated with the single drug or controls. Obtained results suggested that combination therapy with IL-2 and SPG effectively induced NK cells and lymphokine-activated killer cells in vivo and may lead to greater clinical benefit in the treatment of malignancies.

Animals↗