Biomedical subjects

Kiyoshi Ishikawa

Publications and source records attributed to Kiyoshi Ishikawa.

10 recordsLinked to original sources

PubMed2006

Surface relaxation of polarized Xe atoms dissolved in deuterated ethanol.

We measured the spin relaxation of polarized xenon atoms dissolved in deuterated ethanol. Surface relaxation was suppressed by coating the cell walls with deuterated eicosane. From the dependence of the decay rate on temperature and static magnetic field, we obtained the correlation time of random fluctuations of the local field at the liquid-solid interface. By varying the cell volume, the wall coating, and the surface area of the eicosane, we measured the contribution of the spin-rotation interaction to the relaxation. The use of both deuterated molecules enables us to distinguish surface relaxation from the magnetic dipole-dipole and spin-rotation interactions in solution.

Journal Article↗

PubMed2006

[Minimally invasive surgery for primary hyperhidrosis].

Nine hundred twenty-three thoracoscopic sympathectomies for primary hyperhidrosis were performd in 462 patients (180 men, 282 women). Mean age was 29.2 (11-61) years. Synchronous bilateral sympathectomies were performed in 461 patient: right side alone in 1 patient. We started thoracic sympathectomy for primary hyperhidrosis under a thoracoscope using a 10 mm rigid endoscope in 1992. At present, we perform the surgery using a 3 mm rigid scope. The majority of our patient were satisfied with the result of operation. There is general agreement that postoperative side effect, such as compensatory and gustatory sweating, can cause discomfort and affect overall success. Thoracoscopic sympathectomy for primary hyperhidrosis is minimally invasive surgery and provides less pain and better cosmesis and short hospital stay, as compared with the conventional techniques. However, new technique is necessary to decrease compensatory sweating after the operation in the future and we should undergo a meticulous and critical selection to the patients in outpatient clinic.

Adolescent↗

PubMed2005

Transplantation of rat hepatic stem-like (HSL) cells with collagen matrices.

Organ restitution using somatic stem cells is of great clinical interest. Recent advances in the field of tissue engineering have demonstrated that the use of collagen matrices as scaffolds facilitates tissue reconstruction. Here, we examine the efficacy of transplantation of HSL cells, a previously established liver epithelial cell line with a potential for differentiation, using collagen scaffolds. To this end, HSL cells were transplanted into Nagase's analbuminemic rat with spongy or gelatinous type I collagen matrices. Consequently, immunohistochemical analyses and genomic PCR experiments revealed engraftment of the transplanted cells. Furthermore, the levels of serum albumin in recipient rats were found to increase up to 2.5-fold relative to controls after transplantation. These findings suggest that HSL cells are able to differentiate into functional hepatocytes in vivo, and that biodegradable collagen matrices enhance this phenomenon by providing an appropriate microenvironment for hepatocytic repopulation.

Journal Article↗

PubMed2005

Highly time-resolved correlation measurement between laser and synchrotron radiation pulses without synchronization control.

A mode-locked laser has been introduced in combination with synchrotron radiation to establish a versatile technique for highly time-resolved correlation measurements utilizing the short-pulse and high-pulse frequency characteristics of both photon sources. Successive pulse timing delay detected by nonlinear optical mixing between the two sources yields a cross-correlation profile capable of accurate measurement of the picosecond pulse profile of the synchrotron radiation without any synchronization control. Although the experiment was performed in the visible spectral domain, the present technique opens up a methodology for time-resolved spectroscopy in femtosecond and higher-energy domains by introducing a suitable nonlinear process that informs of the pulse coincidence between the two radiation sources.

Journal Article↗

PubMed2005

Smoking history before surgery and prognosis in patients with stage IA non-small-cell lung cancer--a multicenter study.

The prognosis of lung cancer patients with surgically resected non-small-cell lung cancer (NSCLC) can be predicted generally from age, sex, histologic type, stage at diagnosis, and additional treatment. Nine studies have reported that a history of smoking before diagnosis influences the prognosis of the disease in lung cancer patients. In this study, a total of 3082 patients who underwent surgery and were diagnosed with primary pathological stage IA NSCLC at 36 national hospitals from 1982 to 1997 were analyzed for the effect of smoking on survival. Smoking history and other factors influencing either the overall survival or the disease-specific survival rates of patients were estimated with the Cox proportional hazards model. Multivariate analysis demonstrated significant associations between overall survival and age (P < 0.0001), sex (P = 0.0002), and performance status (PS) (P < 0.0001). Disease-specific survival was associated with age (P = 0.0063), sex (0.00161), and PS (P = 0.0029). In males, disease-specific survival was associated with age (P = 0.0120), PS (P = 0.0022), and pack-years (number of cigarette packs per day, and years of smoking) (P = 0.0463). These results indicate that smoking history (pack-years) is important clinical prognostic factor in estimating disease-specific survival, in male patients with stage IA primary NSCLC that has been surgically resected.

Aged↗

PubMed2005

Novel approach for a pulmonary bronchogenic cyst: a report of a case.

We present a case of a bronchogenic pulmonary cyst in a 48-year-old patient. We performed [corrected] mucoclasis using argon laser photocoagulation following resection of mucosa, closure of some drainage bronchus, and covering of the inner surface by the intrapulmonary bronchogenic cyst with an [corrected] absorbable vicryl mesh. At [corrected] 4-year [corrected] follow-up, the patient had no signs of recurrence.

Bronchogenic Cyst↗

PubMed2004

Magnetic resonance imaging of spin-polarization transfer of polarized Xe atoms dissolving into ethanol.

We detect the free-induction signals of xenon atoms polarized by spin-exchange optical pumping. The temperature dependence of dissolution and spin-polarization transfer of xenon atoms to ethanol is measured by simultaneous detection of both xenon and proton signals. The polarization of proton is efficiently enhanced in the xenon-saturated solution at low magnetic fields. The large polarization and chemical shift enable us to obtain clearly the distribution image of xenon atoms near the gas-liquid and liquid-liquid boundaries. Therefore the localization of polarized xenon atoms is observed near the surface. By time-resolved magnetic resonance imaging of polarized xenon and polarization-enhanced proton, the spin dynamics is qualitatively studied for the nuclear spins interacting with each other in a dense solution.

Journal Article↗

PubMed2004

Cerebral fat embolism diagnosed by magnetic resonance imaging at one, eight, and 50 days after hip arthroplasty: a case report.

PURPOSE: To describe cardiovascular collapse during a cemented hip hemiarthroplasty in a patient who, despite a successful cardiopulmonary resuscitation, remained in a persistent vegetative state due to cerebral fat embolism diagnosed by magnetic resonance imaging (MRI). CLINICAL FEATURES: A 75-yr-old woman with no medical history underwent cemented hip hemiarthroplasty under spinal anesthesia for a right femoral neck fracture. Shortly after insertion of the prosthesis, a sudden oxygen desaturation, hypotension, bradycardia, and cardiac arrest occurred. The patient was successfully resuscitated, but did not regain consciousness. The patient developed high-grade fever, thrombocytopenia, anemia, and oliguria. MRI scans of the brain revealed multiple high intensity signals throughout the white matter, the basal ganglia, the cerebellum, and the brain stem. The diagnosis of fat embolism was made on the basis of clinical findings and MRI images. Although her cardiorespiratory status improved over the next week, the patient remained in a persistent vegetative state. CONCLUSION: When fat embolism is suspected, serial MRI scans of the brain should be performed to diagnose the etiology of cerebral embolism as well as to evaluate the severity of brain damage.

Aged↗

PubMed2004

Lung adenocarcinoma with coexisting pulmonary cryptococcoma.

A 73-year-old female was referred to our hospital in June 2000 for the evaluation of an abnormal shadow in the left upper lobe of her lung and two other shadows in the left lower lobe. A computed tomography examination revealed an ill-defined tumor with ground glass opacity in the left upper division segment, suggesting a primary lung adenocarcinoma, and two well-defined nodules in the left lower lobe, suggesting metastatic carcinomas. A transbronchial lung biopsy of the tumor in the upper division segment confirmed the presence of an adenocarcinoma but failed to provide a histological diagnosis for the nodules in the lower lobe. A partial resection of the left lower lobe using video-assisted thoracoscopy revealed granulomatous tissue with no signs of malignancy. A curative resection of the adenocarcinoma in the left upper division segment was therefore performed. Histologically, the resected specimens obtained from the left lower lobe were diagnosed as cryptococcomas. The patient was diagnosed as having a stage IA lung adenocarcinoma and two cryptococcomas. The patient is presently well and has not experienced any recurrences or relapse for 3 years since the resection.

Adenocarcinoma↗

PubMedDate not supplied

Pulmonary dirofilariasis: computed tomography findings and correlation with pathologic features.

OBJECTIVE: The purpose of this study was to describe the computed tomography (CT) and pathologic features of 5 nodules of pulmonary dirofilariasis in 4 patients. METHODS: Four patients with 5 nodules of pathologically confirmed pulmonary dirofilariasis who under went CT were enrolled, and the imaging interpretations were retrospectively compared with the histopathologic characteristics. RESULTS: Three of the 4 patients had a solitary nodule, and the remaining patient had 2 nodules. All the nodules were distributed in the right lower lobe and were attached to the pleura. They were all round or oval in shape and ranged in size from 11 to 22 mm in largest diameter (mean=17 mm). On thinner section CT, the nodules had a well-defined smooth margin with or without a shallow notch; they were connected to the arterial branch and, occasionally, to the venous branch. On contrast-enhanced CT, all the nodules contained a homogeneous low-attenuation area, which corresponded to areas of coagulative necrosis on histopathologic examination. CONCLUSION: Although the CT findings of a pulmonary dirofilariasis nodule are nonspecific, awareness of the findings on contrast-enhanced CT and the pathologic appearance of this rare benign condition may facilitate its differentiation from a malignant nodule.

Aged↗