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Biomedical subjects

T Anazawa

Publications and source records attributed to T Anazawa.

16 recordsLinked to original sources
PubMed2005

Treatment of external iliac artery dissection with endovascular stent placement in a patient with simultaneous pancreas and kidney transplantation.

Dissection of the external iliac artery is a rare but serious complication after transplantation, leading to graft loss. Stent angioplasty has been accepted for iliac artery dissection, but the safety and benefits of this procedure in transplantation are unclear. We report a case of right external iliac artery dissection with simultaneous kidney and pancreas transplantation, which was noticed during the operation. A self-expandable metallic stent was inserted from the right femoral artery to the dissected area and arterial blood flow was immediately restored. The postoperative clinical course was uneventful and soon after transplantation both the kidney and pancreas graft functioned well. Together with a previously reported six cases of stent replacement with transplantation and our case, no complication related to this procedure was reported, and in six cases the arterial flow was restored and graft function was improved. Endovascular stent replacement may be a safe and effective procedure for iliac artery dissection in transplantation.

Adult↗
PubMed2005

Evaluation of energy state of islet independent of size using a newly developed ATP bioluminescence assay.

ATP content or energy charge (EC) of islets may be a good parameter to assess viability. In this study, we examined adenine nucleotides and EC of freshly isolated or 24-hour cultured rat islets of various diameters using a novel bioluminescent enzymatic cycling assay system. For freshly isolated islets, ATP content and islet diameter showed a high correlation (r = 0.842, P < .001), but a significant correlation was not observed for cultured islets (r = 0.284) when all islets were included for the analysis. When only the cultured islets with a diameter <350 microm were included for analysis, a significant correlation was observed (r = 0.719). EC of freshly isolated islets fluctuated widely irrespective of diameter, in contrast with results of 24-hour cultured islets, which showed a stable, high EC, regardless of diameter. These data suggest that the ATP content of islets correlates with the islet size and that EC of islets widely fluctuates following isolation, indicating a significant role of monitoring ATP and EC of islets before transplantation.

Adenosine Triphosphate↗
PubMed1999

A capillary-array electrophoresis system using side-entry on-column laser irradiation combined with glass rod lenses.

We have developed a simple and high-throughput capillary-array electrophoresis system that uses side-entry on-column laser irradiation. The number of capillaries in an array is generally limited by laser-power attenuation along the array due to reflection and divergence. We overcame these problems by placing the capillaries in water and adding glass rod lenses between the capillaries. As a result, up to 45 capillaries could be simultaneously irradiated with a single laser beam and the fluorescence from all the capillaries could be detected with high sensitivity. We demonstrated the high throughput of 12 kbp/h with a 45 capillary array using this system.

Electrophoresis, Capillary↗
PubMed1999

Effects of combined emergency percutaneous cardiopulmonary support and reperfusion treatment in patients with refractory ventricular fibrillation complicating acute myocardial infarction.

OBJECT: We conducted a prospective study to determine whether or not combined emergency percutaneous cardiopulmonary support (PCPS) and coronary reperfusion treatment are useful for acute myocardial infarction (MI) patients with unsynchronized electric shock-resistive ventricular fibrillation (VF). PATIENTS AND METHODS: Thirty-two acute MI patients who lapsed into the refractory VF were entered into the study. Group 1 consisted of 19 patients with VF outside the hospital, and Group 2 consisted of 13 patients with VF immediately after arrival at the hospital. The primary endpoint was successful reperfusion, return of spontaneous circulation and good recovery without neurologic disability. RESULTS: The infarct-related arteries showed a significant difference between Groups 1 and 2. However, the two groups had similar rates of successful reperfusion (84.6% vs 94.7%, respectively) and return of spontaneous circulation (89.5% vs 84.6%, respectively). The rates of good recovery were similarly low in both groups (5.3% vs 15.4%, respectively). CONCLUSION: Combined emergency PCPS and reperfusion treatment produced high return of spontaneous circulation, however the neurologic outcome was low.

Assisted Circulation↗
PubMed1997

[The statistics of inpatients at Department of Neuropsychiatry in Sapporo Medical University Hospital (October, 1983 - March, 1996)].

The role of university hospitals should be re-examined considering the recent situation in psychiatrical health care. In this report, we investigated inpatients of neuropsychiatry in Sapporo Medical University Hospital from various aspects. Statistics were gathered on 1) age and sex, 2) address, 3) admission form based on the mental health law, 4) the number of admissions and discharges per year, 5) hospitalization term, 6) diagnostic group, 7) diagnosis, 8) rates of re-admission and re-admission within three months, 9) age and sex of schizophrenia patients and 10) age and sex of patients with affective disorders from October 31, 1983 to March 31, 1996. In our hospital, the rates of the inpatients with dementia and personality disorders are higher than those in other university hospitals. The reason for the high rate of personality disorders is elusive; however, most of the dementia patients enter our hospital mainly because we concentrate on a special research project about dementia. These data indicate that a specific function is required in university hospitals. In recent years, however, the surroundings of people with mental disorders have become more complicated, and the services for them have become diversified. However, it is very difficult for university hospitals to provide them with all such services, as the hospitals fulfill just one specialized function among the necessary services.

Adolescent↗
PubMed1995

Microscopic analysis of the elastic properties of nebulin in skeletal myofibrils.

The elastic properties of nebulin were studied by measuring the elasticity of single skeletal myofibrils, from which the portion of the thin filament located at the I band had been selectively removed by treatment with plasma gelsolin under rigor conditions. In this myofibril model, a portion of each nebulin molecule at the I band was expected to be free of actin filaments and exposed. The length of the exposed portion of the nebulin molecule was controlled by performing the gelsolin treatment at various sarcomere lengths. The relation between the passive tension and extension of the exposed portion of the nebulin showed a convex curve starting from a slack length, apparently in a fashion similar to that of wool. The slack sarcomere length shifted depending on the length of the exposed portion of the nebulin, however, the relation being represented by a single master curve. The elastic modulus of nebulin was estimated to be two to three orders of magnitude smaller than that of an actin filament. Based on these results, we conclude that nebulin attaches to an actin filament in a side-by-side fashion and that it does not significantly contribute to the elastic modulus of thin filaments. The relation between the passive tension and extension of connectin (titin) was obtained for a myofibril from which thin filaments had been completely removed with gelsolin under contracting conditions; this showed a concave curve, consistent with the previous results obtained in single fibers.

Actins↗
PubMed1994

Structural and functional reconstitution of thin filaments in skeletal muscle.

Thin filaments were reconstituted by incorporating exogenous actin, tropomyosin and troponin into glycerinated skeletal muscle fibres or myofibrils. Firstly, thin filaments except short fragments at the Z line were selectively removed by treatment with plasma gelsolin, an actin severing protein. As a result, the fibres (or fibrils) lost the ability to generate active tension. Next, actin filaments were reconstituted by adding purified G-actin which polymerizes onto the actin fragments which remained at the Z line. Rhodamine phalloidin staining of myofibrils showed that exogenous actin was incorporated into the position where the intrinsic thin filaments located. Thin section electron micrographs of fibres showed that reconstituted actin filaments ran from the Z line to the inside of the A band, with some reaching the H zone. The number density of reconstituted actin filaments in the A band was about 20% of that found in intact fibres. The actin filament-reconstituted fibres (or fibrils) generated active tension in a Ca(2+)-insensitive manner and the tension was reversibly suppressed by 2,3-butanedione 2-monoxime. The recovered active tension was about 20% of tension developed by intact fibres. These results indicate that reconstituted actin filaments bear active tension similar to that borne by intact thin filaments. Thin filament-reconstituted fibres, which were prepared by adding purified tropomyosin-troponin complexes into actin filament-reconstituted fibres, showed Ca(2+)-sensitive tension generation. The maximum tension generated was not affected by the presence of tropomyosin and troponin. SDS-PAGE analysis showed that more than 25% of actin and 20% of tropomyosin and troponin was incorporated into the reconstituted fibres. These results indicate that the structure and function of thin filaments are substantially reconstituted by self-assembly of actin, tropomyosin and troponin. The reconstituted fibres and fibrils will be useful for studying the molecular mechanism of muscle contraction and its regulation.

Actin Cytoskeleton↗
PubMed1993

Spontaneous tension oscillation (SPOC) of muscle fibers and myofibrils minimum requirements for SPOC.

Several years ago, we found a new chemical condition for the spontaneous oscillatory contraction of glycerinated skeletal muscle and named it "SPOC". The condition was such that MgATP coexists with its hydrolytic products, MgADP and inorganic phosphate (Pi). Micromolar concentrations of free Ca2+ were not necessarily required for this oscillation. Here, we summarize our recent work on the mechano-chemical properties of SPOC not only in glycerinated single fibers and myofibrils of skeletal muscle (fast type) but also in glycerinated small bundles of cardiac muscle; the isometric tension and its oscillation were examined at various concentrations of MgATP, MgADP and Pi while controlling the concentration of free Ca2+; we constructed a three-dimensional "state diagram" taken against the concentrations of MgADP, Pi and free Ca2+. The 3-D state diagram clearly showed the existence of three regions corresponding to three muscular states; the SPOC region was located in between the regions for contraction (without oscillation) and relaxation. Based on these results, we discuss the mechanism of SPOC, especially the minimum requirements for its occurrence. Finally, we suggest that slow shortening and quick lengthening repeatedly occur every half-sarcomere through the transition between the two states, where weak-force-generating complexes or strong-force-generating complexes are dominant; the transition may be induced by a coupling with the mechanical states of cross-bridges and/or thin filaments.

Animals↗
PubMed1992

Spontaneous oscillation of tension and sarcomere length in skeletal myofibrils. Microscopic measurement and analysis.

We have devised a simple method for measuring tension development of single myofibrils by micromanipulation with a pair of glass micro-needles. The tension was estimated from the deflection of a flexible needle under an inverted phase-contrast microscope equipped with an image processor, so that the tension development is always accompanied by the shortening of the myofibril (auxotonic condition) in the present setup. The advantage of this method is that the measurement of tension (1/30 s for time resolution and about 0.05 micrograms for accuracy of tension measurement; 0.05 microns as a spatial resolution for displacement of the micro-needle) and the observation of sarcomere structure are possible at the same time, and the technique to hold myofibrils, even single myofibrils, is very simple. This method has been applied to study the tension development of glycerinated skeletal myofibrils under the condition where spontaneous oscillation of sarcomeres is induced, i.e., the coexistence of MgATP, MgADP and inorganic phosphate without free Ca2+. Under this condition, we found that the tension of myofibrils spontaneously oscillates accompanied by the oscillation of sarcomere length with a main period of a few seconds; the period was lengthened and shortened with stretch and release of myofibrils. A possible mechanism of the oscillation is discussed.

Animals↗
PubMed1991

Spontaneous oscillatory contraction (SPOC) of sarcomeres in skeletal muscle.

Skeletal myofibrils spontaneously oscillate under a condition where ATP, ADP, and Pi coexist and the concentration of free Ca2+ is less than about 1 microM. Although this oscillation phenomenon called SPOC is apparently simple, the molecular mechanism seems to be complex. The SPOC condition and the space-time pattern of SPOC wave suggest that the dynamics of association and dissociation of Pi (ADP) is regulated by the mechanical strain imposed on actin and myosin; the enzymatic activity (ATPase) of actomyosin complex and the mechanical event (contraction) are thus coupled to each other. In this sense, the nature of the mechanochemical enzyme, actomyosin ATPase, is revealed in SPOC.

Adenosine Diphosphate↗