PubMed Health⌕ Search

Biomedical subjects

K Yamanaka

Publications and source records attributed to K Yamanaka.

At least 19 recordsLinked to original sources
PubMed2000

Skin-specific caspase-1-transgenic mice show cutaneous apoptosis and pre-endotoxin shock condition with a high serum level of IL-18.

To study the pathophysiological roles of overexpressed caspase-1 (CASP1), originally designated as IL-1 beta-converting enzyme, we generated transgenic mice in which human CASP1 is overexpressed in their keratinocytes. The transgenic mice spontaneously developed recalcitrant dermatitis and skin ulcers, characterized by the presence of massive keratinocyte apoptosis. The skin of the mice contained the active form of human CASP1 and expressed mRNA for caspase-activated DNase, an effector endonuclease responsible for DNA fragmentation. Their skin and sera showed elevated levels of mature IL-18 and IL-1 beta, but not of IFN-gamma. The plasma from these animals induced IFN-gamma production by IL-18-responsive NK cells. Administration of heat-killed Propionibacterium acnes, a potent in vivo type 1 cell inducer, caused IFN-gamma-mediated lethal liver injury in the transgenic mice, which was completely inhibited by treatment with neutralizing anti-IL-18 Ab. These results indicated that in vivo overexpression of CASP1 caused spontaneous apoptotic tissue injury and rendered mice highly susceptible to exogenous type 1 cell-inducing condition in collaboration with endogenously accumulated proinflammatory cytokines.

Animals↗
PubMed2000

The role of orally administered dimethylarsinic acid, a main metabolite of inorganic arsenics, in the promotion and progression of UVB-induced skin tumorigenesis in hairless mice.

The effect of dimethylarsinic acid (DMA) on skin tumorigenesis by UVB irradiation was examined. Hairless mice (Hos: HR-1) irradiated with UVB at a dose of 2 kJ/m(2) twice weekly, were fed with drinking water containing 1000 ppm DMA, a main metabolite of inorganic arsenics, produced more skin tumors than DMA-untreated mice. Histopathological examination revealed that the mouse malignant tumors with severe atypism appeared only in the treatment group of UVB plus 1000 ppm DMA. These positive results point out the importance of dimethylated metabolites of inorganic arsenic in the process of skin carcinogenesis.

Administration, Oral↗
PubMed2000

Primary intracranial germinoma in the medulla oblongata.

BACKGROUND: Primary intracranial germ cell tumor in the medulla oblongata is very rare; only five cases, including our case, have been reported. CASE REPORT: Our patient, an 18-year-old woman, was diagnosed with a primary intracranial germinoma in the medulla oblongata by an open biopsy. She was treated successfully with chemotherapy and radiosurgery. CONCLUSION: All five tumors in this site were histologically diagnosed as germinomas. The finding of female predominance in germ cell tumors in this region is shown.

Adolescent↗
PubMed2000

Effectiveness of cancer vaccine therapy using cells transduced with the interleukin-12 gene combined with systemic interleukin-18 administration.

We introduced the interleukin-12 (IL-12) gene into mouse renal cell carcinoma (RenCa) cells to develop a tumor vaccine and to examine mechanisms of tumor rejection. IL-12-secreting RenCa (RenCa/IL-12) cells were completely rejected when implanted into syngeneic BALB/c but not athymic nude mice, suggesting that T cells were involved in this antitumor effect. Depletion of natural killer (NK) cells in nude mice did not affect the tumor growth of RenCa/IL-12. The simultaneous injection of mitomycin C-treated RenCa/IL-12 inhibited the tumor growth of parental RenCa injected at a distant site, whereas injection of mitomycin C-treated parental RenCa did not. The antitumor effect of RenCa/IL-12 as a cancer vaccine was induced by CD8+ T cells and NK cells and was inhibited by CD4+ T cells. Although the systemic administration of recombinant IL-18 (rIL-18) alone did not inhibit the tumor growth, it did enhance the cancer vaccine effect of RenCa/IL-12. The combination therapy of RenCa/IL-12 and the systemic administration of rIL-18 retarded even the growth of established tumors. The effector cells of this combination therapy consist not only of CD8+ T cells and NK cells but also of CD4+ T cells. This synergistic cancer vaccine effect of in situ secretion of IL-12 and the systemic administration of rIL-18 may be attributed to a functional change of CD4+ T cells.

Animals↗
PubMed2000

Significance of human testicular mast cells and their subtypes in male infertility.

The mast cell populations in the human testis were examined using immunohistochemical techniques in five fertile volunteers and 12 patients with obstructive azoospermia, seven patients with idiopathic azoospermia, and 30 patients with varicocele. The number of mast cells per seminiferous tubular section was significantly increased (P < 0.05) in the men with idiopathic azoospermia. In the normal testes, mast cells containing only tryptase were the predominant subtype. In the patient groups, the predominant subtype of mast cell was shifted to that containing both tryptase and chymase. The average number of mast cells containing both tryptase and chymase per seminiferous tubular section was significantly increased (P < 0.05) compared with the controls in patients with obstructive azoospermia, idiopathic azoospermia, and varicocele. The number of mast cells containing only tryptase was not increased in infertile men. The selective expansion of the mast cell population containing both tryptase and chymase may be related to spermatogenetic disorders and testicular fibrosis.

Adult↗
PubMed2000

Oncostatin M is produced during pregnancy by decidual cells and stimulates the release of HCG.

Oncostatin M (OSM) is a member of the interleukin-6 superfamily and a multifunctional cytokine that effects the growth and differentiation of many different cell types. OSM concentrations in the sera of pregnant women were found to be significantly higher than those of non-pregnant women. Western blot analysis revealed that the OSM protein was present in the decidua and chorionic tissue in each trimester. Throughout pregnancy, the amount of the OSM protein in the decidua was larger than that in the chorionic tissue. Immunohistochemistry using an anti-OSM monoclonal antibody demonstrated that OSM was mainly localized in the decidual glands and stroma. OSM transcripts in the decidua and the chorionic tissue were detected during each trimester by reverse transcription-polymerase chain reaction (RT-PCR). The regulation of human chorionic gonadotrophin (HCG) release by the placenta in first trimester stimulated with recombinant OSM was also investigated. Stimulation of the placenta by OSM augmented HCG release in a time- and dose-dependent manner. HCG release induced by recombinant human OSM was completely blocked by antibodies against OSM and the signal transducer, gp130, but only partially inhibited by antibodies against the leukaemia inhibiting factor (LIF) receptor. These results suggest that OSM molecules produced by decidual glands and stromal cells during pregnancy have an important role in placental endocrine function.

Antibodies, Monoclonal↗
PubMed2000

Cassiopeia flap: modification of Limberg flap for saving normal skin.

Local flaps have the advantages of texture matching and increased flap survival rate. The proper local flap planning for each lesion causes the dermatologist to be reluctant to employ them. We propose a modified local flap, the "Cassiopeia flap", with three simple marking points made on the ends of the diameter and on the equidistant point along the diameter; two points from equilateral triangles form a "W (Cassiopeia)". We applied this modification to ten lesions on the face, scalp, trunk and thigh with excellent results.

Dermatologic Surgical Procedures↗
PubMed2000

Successful manual reduction of locked metacarpophalangeal joints in fingers.

BACKGROUND: Many studies on the etiology and operative treatment of locked metacarpophalangeal joints in fingers have been reported, but there have been few investigations on manual reduction. The rate of success of manual reduction in previous reports has been low, and no consensus has been reached with regard to the best method of manual reduction. On the basis of our experience with operative treatment, we devised a safe method of manual reduction. METHODS: Between January 1987 and December 1995, we reduced a locked metacarpophalangeal joint in twelve female patients; every locked finger was successfully reduced, and complications such as fracture did not occur during manual reduction. The average duration of follow-up was five years and nine months (range, three years and two months to nine years and three months). RESULTS: Six patients had no recurrence of the locking. Four of the six remaining patients had one or two incidents of locking, had no alteration in the activities of daily living, and did not want operative treatment. The two remaining patients reported that they had incidents of locking several times a day, and they requested operative treatment as they were afraid of additional recurrences. One patient had an open reduction fifteen months after the initial episode of locking, and the other patient elected not to have an operation for personal reasons. CONCLUSIONS: We believe that our method of manual reduction should be used to treat a locked metacarpophalangeal joint in a finger and that operative treatment should be limited to patients in whom manual reduction is unsuccessful or the reduction is unstable.

Adult↗
PubMed2000

Elevated risk of tuberculosis by occupation with special reference to health care workers.

We conducted a study to evaluate tuberculosis (TB) risk in Japan by work performed, either paid or unpaid. We collated information on sex, age, employment category, occupation, and family history from 1120 registration cards of new TB cases at two wards in Nagoya City over seven years (1989-1995). We used census data and data from the Survey of Physicians, Dentists and Pharmacists conducted in 1990 to estimate the population at risk by employment category and occupation. Elevated TB incidence rates were observed for female nurses (SIR: 3.81; 95% CI: 1.97-6.65), clinical laboratory technicians (SIR: 25.00; 6.81-63.99), and males without a paid job (SIR: 1.35; 1.20-1.53). A work environment conducive to transmission may have increased the TB risk in female nurses and clinical laboratory technicians. Male jobless people and institutionalized elderly residents may have enhanced the TB risk for males without a paid job.

Adolescent↗
PubMed2000

[Cervical pyogenic spondylodiscitis: 4 cases report and a review of the literature].

We report 4 cases of cervical spondylodiscitis presenting neurological and/or neuroradiological abnormalities. Such a lesion is rare in the cervical spine of adults, but should be suspected when the patient has radiculopathy and/or myelopathy associated with inflammatory signs. We discussed the clinical characteristics and the procedures of the diagnosis and treatment of cervical spondylodiscitis. Early and definitive diagnosis can be achieved by cervical X-ray, MR imaging and biopsy. It is very important to evaluate the pyogen for the lesion by needle biopsy. When the patient has the compression of the spinal cord and/or nerve roots and the neurological findings of radiculopathy and/or myelopathy, surgical exploration and decompression of the spinal cord and/or nerve roots should be carried out as soon as possible. Anterior debridement and fusion should be performed using the effective antibiotics. We were able to achieve good prognosis by treatment following this procedure of diagnosis in the four cases of cervical spondylodiscitis mentioned.

Adult↗
PubMed2000

[Adenocarcinoma of the ileal segment with transitional cell carcinoma of the bladder following ileocytoplasty: a case report].

A 67 year-old woman visited our hospital complaining of pollakisuria. She had undergone left nephrectomy and augmentation ileocystoplasty for tuberculous bladder atrophy 40 years previously. She underwent a total cystectomy and tubeless ureterocutaneostomy with a preoperative diagnosis of muscle-invading transitional cell carcinoma of the bladder. The pathological diagnosis was adenocarcinoma of the ileal segment and transitional cell carcinoma of the original bladder. This is the first case report of adenocarcinoma of the ileal segment and transitional cell carcinoma of the original bladder among 22 patients suffering from bladder cancer after ileocystoplasty.

Adenocarcinoma↗
PubMed2000

The effect of modified ultrafiltration in pediatric open heart surgery.

Since 1997 we have performed modified ultrafiltration (MUF) in pediatric open heart operations. To elucidate the clinical effects of MUF, patients under 20 kg in weight who underwent corrective open heart operation since 1997 are divided into 2 cohorts according to the enforcement of MUF (control group versus MUF group) retrospectively. Procedures, age, bodyweight, cardiopulmonary bypass (CPB) time, operation time, amount of donor blood use, postoperative inotrope dose, postoperative intubation time, and postoperative gas exchange capacity of lung expressed with respiratory index (RI) were compared between groups. Furthermore, a multiple linear regression analysis was performed to find independent correlates with postoperative RI. Finally scattergrams of intubation time and RI were drawn against several factors. In univariate analyses, the MUF group had significantly shorter intubation time and better RI. Multivariate analysis revealed that the enforcement of MUF was an independent correlate of postoperative RI. Analyses on the scattergrams revealed that the above mentioned favorable effects of MUF were prominent in the patients younger than 3 years or weighing less than 10 kg. We concluded that MUF had significant effects on pulmonary function preservation in pediatric open heart operations, especially for smaller children.

Body Weight↗
PubMed2000

[Rerupture mechanism of ruptured intracranial dissecting aneurysm in the vertebral artery following proximal occlusion].

Proximal occlusion is commonly employed to prevent rebleeding of intracranial dissecting aneurysms of the vertebral artery (VA), but rebleeding sometimes occurs. To determine the cause of such rebleeding we reviewed nine cases, including eight reported in the literature and one treated at our hospital. We classified the techniques used to proximally occlude the VA into two types. In Type I, occlusion is performed immediately proximal to the aneurysm so that there are no perforating arteries or the posterior inferior cerebellar artery (PICA) between the clip and the aneurysm. In Type II, occlusion is performed proximal to the PICA so postoperative retrograde flow persists from the contralateral VA through the aneurysm into the ipsilateral PICA. Among the four Type I cases reviewed, it was found that the interval between occlusion and rebleeding was very short: three developed rebleeding within four hours of occlusion, and the fourth showed rebleeding on the fourth day. In the five Type II patients, rebleeding occurred more than four days (mean 15.2 days) after occlusion. It is thought that in Type I occlusion, retrograde flow into the aneurysm immediately after occlusion may raise the intraaneurysmal pressure enough to cause rerupture within just a few hours of occlusion. In Type II occlusion, postoperative retrograde flow through the aneurysm into the ipsilateral PICA exists, so the intraaneurysmal pressure is not likely to rise as rapidly, with the result that rebleeding occurred after more than four days probably due to recurrence of dissection. The short interval between proximal occlusion and rebleeding, especially in Type I cases, suggests that postoperative angiography is only of limited usefulness in evaluating the possibility of rebleeding. The mortality rate reported for cases with reruptured vertebral dissecting aneurysms after proximal occlusion is very high (55.6%). These data indicate that surgical trapping or endovascular intraluminal occlusion, which is difficult to perform in some patients, should be considered the most suitable procedure from the view point of preventing postoperative rebleeding.

Cerebral Hemorrhage↗
PubMed2000

[Proceeding of the workshop "What an ideal clinical microbiological laboratory should be". The 33rd in-service training course for medical technologists of university hospitals in 1999].

In the workshop of the 33rd in-service training course for University Hospital Medical Technologists in 1999(sponsorship: the ministry of Education), all groups of participants were charged with discussing an ideal clinical microbiology laboratory. In conclusion, the successful operation of the ideal system of clinical microbiology should require a high level of competence in every staff member of the hospital. It must not be focused solely on the sophistication of laboratory methods. We must modify our behavior effectively and establish a good collaborative partnership with physicians and other health care professionals.

Clinical Laboratory Techniques↗
PubMed2000

[Gamma knife radiosurgery for skull base meningiomas: the treatment results and patient satisfaction expressed in answers to a questionnaire].

Skull base meningiomas can be treated by radiosurgery with low morbidity. We evaluated the effectiveness of gamma knife radiosurgery for skull base meningiomas. We also evaluated patient satisfaction through answers to a questionnaire. We treated 77 patients of skull base meningiomas using gamma knife radiosurgery from January 1994 to June 1998. Among these patients, 73 patients were able to be followed up from 6 to 60 months (average 25 months). The diagnosis was made by operations on 39 patients (53%), and on magnetic resonance imagings in 34 patients (47%). 21 patients (28.7%) had residual tumors after operations and 18 patients (24.3%) had recurrence after operations. 40% of neurological deficits occurred after previous operations and 20% of the patients were asymptomatic. The locations of the tumors were mainly the cavernous sinus region in 35 patients and the petroclival region in 20 patients. The tumor sizes were 8.6 to 58.3 mm (average 24.7 mm) and five cases of tumors with a mean diameter above 40 mm were treated by two-staged radiosurgery. Treatment volume was 0.3 to 31 ml (average 9.8 ml). The treatment dose was 8 to 16 Gy (average 11.2 Gy) at the tumor margin. The tumor decreased in size in 50 patients (68%) and was unchanged in 20 patients (28%) and we were able to achieve 96% tumor growth control. The clinical symptoms improved in 22 patients (30.1%) and were unchanged in 47 patients (64.4%) and only 4 patients (5.5%) showed deterioration. 50 patients (68%) felt clinical improvement and only 3 patients (4%) sensed deterioration. 58 patients (79%) were able to continue their previous work. Gamma knife radiosurgery has a very low morbidity rate and enables good tumor control, and patients with skull base meningiomas express satisfaction with the treatment results.

Adolescent↗
PubMed1999

Stabilization of iron regulatory protein 2, IRP2, by aluminum.

Iron regulatory protein 2 (IRP2) is one of the central regulators of iron homeostasis. IRP2 regulates expression of molecules involved in iron metabolism by binding to iron responsive elements (IREs) in the transcripts of those molecules in iron depletion. IRP2 is regulated by the accelerated degradation initiated by the iron-catalyzed oxidation. Here we report that aluminum antagonizes the iron-induced decrease in IRE binding activity of IRP2. Aluminum also inhibits iron-induced oxidation of IRP2 in vitro. These results suggest that aluminum stabilizes IRP2 by interfering with the iron-catalyzed oxidation, which results in perturbation of iron metabolism.

Aluminum↗