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Biomedical subjects

A Kawamura

Publications and source records attributed to A Kawamura.

At least 91 records · Page 5Linked to original sources
PubMed1997

Successful preoperative diagnosis of a cholecystogastric fistula using endoscopic retrograde cholangiography: report of a case.

A 64-year-old woman who presented with pyrexia and severe right upper quadrant abdominal pain was suspected of a having a cholecystogastric fistula by the abdominal plain radiograph and gastrointestinal endoscopic findings. The diagnosis was established preoperatively by endoscopic retrograde cholangiography (ERC), following which a cholecystectomy and fistulectomy with resection of the extrahepatic bile duct and hepaticojejunostomy were performed. The patient has remained well since her discharge from hospital.

Biliary Fistula↗
PubMed1997

Acute cellular damage in medial smooth muscle cells following experimental coronary angioplasty in dog. Damage of cytoskeleton and apoptosis.

The purpose of the present study was to investigate the responses of the cytoskeleton and the presence of apoptosis following acute damage of medial smooth muscle cells after percutaneous transluminal coronary angioplasty (PTCA). We killed 20 dogs, 4h and 4 days after PTCA (n=10 in each group). Ten dogs without PTCA were used as controls. PTCA was achieved by inflating balloon catheters two times, for 60s each time, to 150 PSI, followed by a 60-s deflation. The coronary artery obtained from each dog was fixed in 10% formalin neutral buffer solution. The response of the cytoskeleton was studied immunohistochemically. using monoclonal antibodies against alpha-smooth muscle actin, vimentin, and beta-tubulin. Proliferation was determined by proliferating cell nuclear antigen (PCNA), and DNA fragmentation indicating apoptosis was determined by in situ nick end labeling. Four h after PTCA, endothelial denudation, microscopic mural thrombi, rupture of the internal elastic membrane, medial tear, and stretched smooth muscle cells with nuclei were found at the PTCA site. An immunohistochemical study revealed diffuse reduction or defective immunoreactivity in each cytoskeleton of medial smooth muscle cells, 4h after PTCA. The extent of positive immunoreactivity in the media decreased to 45+/-11% in alpha-smooth muscle actin (control value, 80+/-10%), 9+/-8% in vimentin (control value, 83+/-9%), and 10+/-7% in beta-tubulin (control value, 75+/-8%). The decrease was more significant in vimentin and beta-tubulin than in alpha-smooth muscle actin. Four days after PTCA, the features were diffuse cell death and the focal proliferation of medial cells, as well as macroscopic intramural thrombi. The extent of positive immunoreactivity in the media was 15+/-9% in alpha-smooth muscle actin, 13+/-7% in vimentin, and 14+/-11% in beta-tubulin. There were no smooth muscle cells with positive PCNA (0%) in the control and 4-h groups, but 4 days after PTCA the percentage was 19+/-4%. In situ nick end labeling showed DNA fragmentation in the nuclei of medial smooth muscle cells at a rate of 15+/-5% 4h after PTCA and at 8+/-6% 4 days after PTCA, compared with 0% in the control. We concluded that severe damage of the cytoskeleton and medial smooth muscle cell death were induced immediately after PTCA, followed by proliferation of smooth muscle cells. Apoptosis may be partially involved in the death of smooth muscle cells, in addition to necrosis. Damage to the cytoskeleton and apoptosis may play an important role in the pathogenesis of acute lesions and the proliferation of smooth muscle cells after PTCA.

Angioplasty, Balloon, Coronary↗
PubMed1997

Induction of differentiation by wild-type p53 gene in a human glioma cell line.

Wild-type human p53 gene was transfected into the human glioma cell line T-98G. Transfectants were then isolated and characterized for growth potential and differentiation phenotype. Growth suppression, overexpression of GFAP, and accumulation in G1 phase were more commonly observed in transfectants than in T-98G cells. p21WAF1/CIP1 was overexpressed in transfectants, and the binding of PCNA and CDK 2 to p21WAF1/CIP1 were increased in transfectants. These results suggested the roles of p21WAF1/CIP1, PCNA, and CDK2 in regulation of differentiation in glioma cells and the gene transfer of wild-type p53 may be effective for the control of glial differentiation in glioma cells.

Brain Neoplasms↗
PubMed1997

Occurrence of high ratio of males after introduction of minocycline in a colony of Leptotrombidium fletcheri infected with Orientia tsutsugamushi.

In colonies of Leptotrombidium fletcheri mites infected with Orientia tsutsugamushi (Ot), the agent of scrub typhus, males rarely appear. In the present study, the development of a high ratio of males was observed after introduction of minocycline (MC). A high dose of MC was injected subcutaneously into a mouse, and by feeding unfed larvae from an infected mite colony on this mouse, the Ot in the mites were successfully killed. Of a total of 130 unfed larvae attached to the mouse, 29 developed into females; of these, 9 laid an average of 112.4 eggs/female. Unfed larvae in the succeeding generations were attached to untreated mice. All adults in the P and F1 generation were females, and males started to appear at the F2 generation. The ratio of males to females was 332:7, 108:13, 263:61 and 71:9 at the F2, F3, F4 and F5 generations, respectively. These data suggest that Ot in the ovary or gonad may suppress the development of males.

Animals↗
PubMed1997

[Effect of factor XIII on intractable CSF leakage after a transpetrosal-approach operation: a case report].

The authors reported an experience showing that the XIII factor was effective for intractable cerebrospinal fluid (CSF) leakage after a transpetrosal operation to deal with cerebellopontine angle meningioma. A 63-year-old female noted a slight headache and a floating feeling. She became dependent on a stick for walking alone because of gradual gait disturbance. As the headache became more severe, she consulted the outpatient clinic of the department of neurosurgery of Kobe University Hospital. Magnetic resonance images (MRI) revealed a 4.3 x 3.0cm sized right cerebellopontine angle tumor. She was admitted for the purpose of removal of the tumor and preoperative examinations were performed. Neurological findings on admission showed only slight right cerebellar signs. The operation was performed via the transpetrosal approach and the tumor was totally removed (Simpson Grade II). It took 12 hours 40 minutes for the operation. The amount of blood loss was 1970ml and the blood transfusion volume was 1200ml. Postoperative course was uneventful and her complaints disappeared. There were no postoperative complications at all, but 2 weeks after the operation, CSF leakage under the skin flap appeared. As subcutaneous fluid collection after skull base surgery is usual, spinal drainage and compression of the skin flap was carried out but these measures were not effective. The collection of fluid did not disappear for 2 weeks. Based on our successful experience with the XIII factor therapy in intractable cerebrospinal fluid leakage from the nose after a transsphenoidal approach operation for recurrent pituitary adenoma, the blood level of the XIII factor activity was examined. As the result was far below the normal limit in this case, the XIII factor was infused at a rate of 750 units per day for 5 days. One week after the administration, the level of the XIII factor became normal. Fluid collection disappeared and the drainage tube was removed. Recently, in neurosurgery, skull base surgery has been used widely and the range of craniotomy has been extended because operations can now be performed without compression of cerebral cortexes. However, operation time has increased and the volumes of bleeding and of blood transfusion are increasing. Postoperative complications such as CSF leakage and infection have become new problems. In this case, the XIII factor was still far below the normal level 2 weeks after the operation and it could be considered to have caused delayed CSF leakage. Some papers have reported that the XIII factor was effective in treating intractable fistula after operations in other surgical areas. However, this is the first report of skull base surgery such as an operation using transpetrosal approach taking advantage of the effect of the XIII factor.

Cerebellopontine Angle↗
PubMed1996

Preferential replication-dependent mutagenesis in the lagging DNA strand in Escherichia coli.

The mutation frequencies attributable to -1 frameshift or one-base substitution in the structural genes coding for resistance to chloramphenicol (Cm) and tetracycline (Tc) were followed over several cycles of DNA replication, and found to differ several-fold, depending on the orientation of the gene on the plasmid with respect to the direction of (unidirectional ColE1-type) replication. The mutation frequency was higher when the reporter gene was present in the plasmid in the same orientation as the direction of the origin, i.e., when the transcription template is the lagging daughter strand, than when the gene was inserted in the opposite orientation. This significant difference in reversion frequencies of genes with different polarities was demonstrated only for a brief period of cell growth (several cycles of replication) after induction of the dnaQ49 mutator, but was not observed when an increased number of replication cycles, was permitted, most probably due to fixation of the mutation into both strands. The mutated intermediate DNA which possesses a misaligned basepair in the Cm gene was demonstrated to be replicated into two progeny DNA molecules; one is the chloramphenicol-resistant (CmR) DNA synthesized from the template strand having the mutation and the other is the CmS DNA from the template strand without mutation. Our results suggest that replication-dependent mutagenesis may occur preferentially in the lagging strand.

Bacteriocin Plasmids↗
PubMed1996

Extracorporeal granulocytapheresis for cancer and rheumatoid arthritis.

In cancer and rheumatoid arthritis, granulocytosis is often observed and indicates the progress of disease. We developed a granulocytapheresis system to permit granulocyte reduction. Cellulose acetate was found to be a selective and effective adsorbent. In an in vivo study using an acetate bead column, 9.2 x 10(8) leukocytes were collected. Initially, granulocytapheresis was applied to terminal patients or those with stage IV cancer. Pain, cough and bloody sputum were reduced in spite of no decrease in tumor size. Granulocytapheresis appears to prevent inflammatory damage in or around the tumor site. This granulocyte reduction technique was also applied to patients with rheumatoid arthritis. The Lansbury index markedly improved after treatment. As cytokines and adhesion molecules might contribute to symptoms, granulocytapheresis may be useful in improving the "Quality of Life" in these diseases.

Aged↗
PubMed1996

Picomole scale stereochemical analysis of sphingosines and dihydrosphingosines.

We have developed a simple picomole (low nanogram) scale HPLC scheme which can separate all eight isomers of sphingosine and dihydrosphingosine thus leading to the identification of their relative and absolute configurations. The amino group of the sample is derivatized to its fluorescent N-naphthimide which is analyzed by normal and chiral phase HPLC, coupled with fluorescence peak detection. If necessary, the results of this HPLC method can be further corroborated by measurements of circular dichroic (CD) spectra of the N-naphthimido-derivatives and/or N,O-chromophoric derivatives.

Chromatography, High Pressure Liquid↗
PubMed1996

[Intraoperative TEE revealed the mitral valve vegetation and the operation was cancelled].

Intraoperative transesophageal echocardiography (TEE) was performed on a 53-yr-old man scheduled for the venous graft in the left leg under general anesthesia. The TEE revealed the severe mitral valve vegetation and because of the finding, the operation was cancelled. Preoperative transthoracic echocardiography showed mitral valve regurgitation only, and not mitral valve vegetation. TEE was useful not only in assessing global and regional cardiac function, but also in visualizing anatomic abnormalities of the heart and their influence on cardiac performance.

Acute Disease↗
PubMed1996

[Posterior cerebral aneurysm associated with complete occlusion of the middle cerebral artery caused subarachnoid hemorrhage: a case report].

The authors reported a rare case of subarachnoid hemorrhage (SAH) from a left posterior cerebral artery (PCA) aneurysm at P2 portion associated with complete occlusion of the ipsilateral middle cerebral artery (MCA). A 65-year-old female suddenly complained of severe headache and was admitted with disturbance of consciousness. Apart from her somnolent condition, she showed no significant neurologic deficits such as aphasia or right hemiparesis. CT scan revealed the finding of SAH dominant in the left sylvian fissure and basal cistern. A small low density area which was considered as an old infarction was also recognized in the left putamen. Angiogram showed a left P2 portion aneurysm associated with complete occlusion of the ipsilateral MCA at its origin. Bilateral PCA was mainly supplied via posterior communicating artery (PCo) from anterior circulation. The clipping of the aneurysm was performed via a subtemporal approach 5 hours after the attack with special attention and care to prevent secondary brain damage due to the ischemic state caused by MCA occlusion. Transient neurological complication such as aphasia and right hemiparesis appeared postoperatively for a few days but recovered almost completely in a week after the ventriculoperitoneal shunt. Indication, timing and technique of operation and management after the operation must be well-discussed for cases of subarachnoid hemorrhage due to an aneurysm associated with ischemic cerebrovascular disease. In our case, we took special care concerning the following points to prevent ischemic complications. 1) The drilling of the temporal bone and a ventricular drainage were performed to ensure minimum retraction of the temporal lobe. 2) Retraction of the cortex was done intermittently to protect the brain from damage as much as possible. 3) Hypotensive conditions were avoided during and after surgery. 4) Continuous infusion of Nicardipine and hypertensive & hypervolemic therapy was started immediately to prevent any complication due to vasospasm. 5) Gentle surgery was carried out around the ischemic brain and vessels. The postoperative result suggested that our treatment to prevent postoperative ischemic complications due to complete occlusion of the right MCA was effective. In this paper we discussed the etiology of P2 portion aneurysm from the literature and by angiographical morphologies. In this case, the P2 portion aneurysm was considered to be produced by increase of hemodynamic stress to the PCA via fetal type PCo due to MCA occlusion. To our knowledge, this paper is the only report of PCA aneurysm associated with MCA complete occlusion brought about by SAH.

Aged↗
PubMed1996

Binding of tacrolimus (FK506) with human plasma proteins re-evaluation and effect of mycophenolic acid.

Protein binding of tacrolimus (FK506) in human plasma was re-evaluated by equilibration dialysis and compared with that of FK506 previously reported by two different methods (about 99 and 77% by an ultrafiltration and ultracentrifugation method, respectively). The binding determined in this study was about 99% irrespective of FK506 concentrations added (0.5-10 ng/ml) and this value was very close to that estimated by the ultrafiltration method. The effect of mycophenolic acid (MPA, an active form of the immunosuppressant mycophenolate mofetil) and its glucuronide (MPAG, a major metabolite of mycophenolate mofetil in human plasma) on the binding was studied at concentration levels of 1 and 10 ng/ml of FK506. The binding was not affected significantly by the addition of MPA (25-100 micrograms/ml) and/or MPAG (100-1500 micrograms/ml). FK506 has already been reported not to cause significant changes of plasma protein binding of MPA. The results indicate that the unbound fraction of FK506 is about 1% in human plasma and that concomitant administration of FK506 and mycophenolic mofetil does not cause the drastic change of the binding of FK506 and MPA with human plasma proteins.

Antibiotics, Antineoplastic↗
PubMed1995

Interaction of FKBP12-FK506 with calcineurin A at the B subunit-binding domain.

Calcineurin is a calcium-dependent protein phosphatase that plays a pivotal role in antigen-stimulated T cell activation. The complexes formed between the immunosuppressants cyclosporin A and FK506 and their respective intracellular binding proteins (immunophilins) block T cell activation by binding to calcineurin. Recent studies have shown that the immunophilin-immunosuppressant complexes interact with the latch region of the calcineurin B subunit (Milan, D., Griffith, J., Su, M., Price, E. R., and McKeon, F. (1994) Cell 79, 437-447). Mutations in the B subunit-binding domain of the calcineurin A subunit result in a reduction of calcineurin activity that correlates with B binding affinity. Calcineurin A subunit mutants D348A, F350A, W352A, S353A, and E359A lost greater than 90% of their activity to activate the transcription factor NF kappa B in Jurkat T cells. Furthermore, calcineurin A subunit mutants of residues Thr351, Leu354, and Lys360 showed NF kappa B transactivation activity and phosphatase activity with increased resistance to FKBP12-FK506 but displayed no or minimal increase in resistance for cyclosporin A inhibition. Together, these results strongly suggest that the B subunit-binding domain is required for calcineurin activity intracellulary and interacts with the FKBP12-FK506 complex.

Amino Acid Sequence↗
PubMed1995

Indocyanine green videoangiographic findings in detachment of the retinal pigment epithelium.

BACKGROUND: Several forms of retinal pigment epithelial detachment have been reported. The authors used indocyanine green (ICG) videoangiography, which is useful to study the choroidal vasculature and Bruch membrane, to study pigment epithelial detachments. METHODS: Ninety-eight pigment epithelial detachments in 75 eyes were classified based on the appearance of choroidal neovascular membranes or late phase findings of ICG videoangiography done at the initial examination. The authors also followed the evolution of 51 such detachments not associated with choroidal neovascularization (CNV). RESULTS: Sixty-four pigment epithelial detachments without CNV were divided into five groups. Among eyes with pigment epithelial detachments that showed intense hyperfluorescence, all except one of the patients had both eyes involved and had several pigment epithelial detachments, sometimes with exudative retinal detachments. Weak hyperfluorescence was observed more often in younger patients. During follow-up of eyes with pigment epithelial detachments that showed irregular hypofluorescence, a neovascular membrane developed in one eye, microrips developed in four eyes and retinochoroidal folds in one eye. Most eyes that showed irregular hyperfluorescence developed atrophy of the retinal pigment epithelium. In 34 pigment epithelial detachments with CNV, either irregular hypofluorescence or absence of fluorescence was observed in areas that corresponded to the pigment epithelial detachment. CONCLUSION: The intense hyperfluorescence is thought to be due to the accumulation of protein-rich fluid within the pigment epithelial detachment. Most pigment epithelial detachments that showed weak fluorescence probably represent variants of central serous choroidopathy. Pigment epithelial detachments that showed irregular hypofluorescence or hyperfluorescence were associated with age-related macular degeneration, and the former was correlated closely with CNV. Close follow-up therefore is recommended for eyes with pigment epithelial detachments that show irregular hypofluorescence.

Adult↗