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Biomedical subjects

H Tamura

Publications and source records attributed to H Tamura.

At least 379 records · Page 21Linked to original sources
PubMed1989

Linear programming models for cost reimbursement.

Tamura, Lauer, and Sanborn (1985) reported a multiple regression approach to the problem of determining a cost reimbursement (rate-setting) formula for facilities providing long-term care (nursing homes). In this article we propose an alternative approach to this problem, using an absolute-error criterion instead of the least-squares criterion used in regression, with a variety of side constraints incorporated in the derivation of the formula. The mathematical tool for implementation of this approach is linear programming (LP). The article begins with a discussion of the desirable characteristics of a rate-setting formula. The development of a formula with these properties can be easily achieved, in terms of modeling as well as computation, using LP. Specifically, LP provides an efficient computational algorithm to minimize absolute error deviation, thus protecting rates from the effects of unusual observations in the data base. LP also offers modeling flexibility to impose a variety of policy controls. These features are not readily available if a least-squares criterion is used. Examples based on actual data are used to illustrate alternative LP models for rate setting.

Computer Simulation↗
PubMed1989

[Clinical evaluations of surgical treatment of infective endocarditis].

This paper shows the clinical evaluations of surgical and medical treatment of infective endocarditis (IE). IE occurred in 33 cases (10.1%) among 372 cases of valve replacement. Of all the 33 patients, IE was consisted of native valve endocarditis (NVE) and prosthetic valve endocarditis (PVE). IE was evaluated as for the microorganism, complication, operative indication and operative mortality. At first, all of NVE underwent surgical treatment, active phase endocarditis 4 and healed endocarditis 14. Microorganism was streptococcus aureus in an overwhelming majority. Operative indications was congestive heart failure in almost all cases, next to vegetation and infection resistant to medical treatment. Operative mortality was 5.6% (1 out of 18 cases), which case was in the septic shock and cerebral bleeding prior to the surgical treatment. The others was satisfactory condition postoperatively. Next of PVE, PVE happened in 15 cases, in which there were 5 cases of bioprosthetic PVE and 10 cases of mechanical valve PVE. Microorganism for PVE was staphylococcus epidermidis in the major part (60%). Mortality in PVE was 53.3% (8 out of 15), but mechanical valve PVE was worse in prognosis than bioprosthetic PVE. Cerebral complications occurred in 3 cases of mechanical valve PVE, on the other hand there was no cerebral complication in bioprosthetic PVE. As for the hemodynamic change in PVE, mechanical valve PVE had the tendency to take the prompt or sudden deterioration of hemodynamics caused by endocarditis surrounding the suture ring, especially in mitral position, on the contrary hemodynamic deterioration was gradually proceeded in bioprosthetic PVE. UCG made much of the diagnosis of PVE, especially in mechanical valve PVE, in which cases endocarditis was recognized only surrounding the suture ring. PVE takes the miserable outcome in many cases, so carefully observation is necessary in order not to lose the timing of the surgical treatment.

Adult↗
PubMed1989

[Time-related degeneration of Carpentier-Edwards bioprosthesis in mitral position].

Carpentier-Edwards bioprostheses have been shown to provide a low incidence of valve-related complications, especially thromboembolism, but the durability has caused the serious concern. This report suggests that Carpentier-Edwards prostheses have been gradually degenerative, and stenotic degeneration and the year after operation are well correlative. In Osaka National Hospital, Carpentier-Edwards prostheses were implanted in 89 patients in mitral position from 1973 to 1981. Of all the patients, 50 patients were undertaken to single valve replacement in mitral position and could be followed up in our department. For a total of 50 patients, materials are 30 patients who could be detected by clinical findings, pulsed Doppler echocardiography, cardiac catheterization and soft X-ray evaluation in explanted prostheses at reoperation. Follow-up duration was ranged 4.2 to 12.1 years with a mean duration of 7.94 years. The age ranged from 32 to 71 years of age. The initial diagnosis of the time-related degeneration was the appearance of newly acoustic rumbiling murmur. Furthermore, regurgitant murmur, arrythmia (atrial fibrillation) and cardiac enlargement were followed in addition to rumbling murmur. The assess of the transmitral flow such as pressure half time and peak pressure gradient by pulsed Doppler echocardiography was the easy way to evaluated the time-related degeneration. Time-related stenotic change by pulsed Doppler was expressed as a linearized curve. At 6 years and below valve function seemed not to be impaired but stenotic dominant degeneration with the cusp tear was prominent beyond 7 years. Cardiac catheterization data could make sure of the pulsed Doppler findings by assessing mitral valve gradient and mitral valve area.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Intra-arterial infusion chemotherapy under flow occlusion using a double lumen reservoir].

Recently, we developed an intrahepatic artery catheter and a device attached with an implantable double lumen reservoir. In this paper, we present clinical experience with this device in 15 cases of hepatocellular carcinoma and the results of an experimental study using canine regarding the significance of arterial infusion therapy with occlusion of hepatic arterial flow. Adriamycin and CDDP were used as anticancer agents, and in 3 out of 15 cases IL-2 and LAK cell were used as chemoimmunotherapy. Twenty-one infusions were possible without any severe side effects. This treatment was also safely done even in the out-patient clinic. In one case extravasation of drug and another case of fever caused by catheter were seen, which was easily diminished by conservative treatment. Ten cases were estimated for antitumor effects and 5 showed partial remission. In experimental study, augmentation of the intrahepatic tissue level of adriamycin was found with occlusion of arterial flow. Intra-arterial infusion therapy using this device promises to be a most useful routine method for cancer control in the outpatient clinic.

Aged↗
PubMed1989

[The determinant factors for open heart surgery with non-blood transfusion--analysis by quantitative theory class II].

The serious complications in the field of cardiovascular surgery are the blood transfusion related problems such as post transfusion hepatitis, AIDS, GVHD and immunosuppressed conditions. These problems have not been settled so far. In our department, open heart surgery with non-blood transfusion is the final goal and extracorporeal circulation with non-blood priming has been indicated under normal conditions. However depending on the cases, blood transfusion is definitely required. Under such circumstances, we analyzed the determinant factors as to whether open heart surgery with non-blood transfusion may be indicated or not, according to the formula based on the quantitative theory (class II). Extracorporeal circulation with non-blood priming were indicated on 124 patients in our department, and they were divided into two groups; blood transfusion group (group I): 64 patients, and non-blood transfusion group (group II): 60 patients. These two groups were compared for study in terms of age, preoperative weight, the body surface area, preoperative Ht value, calculated Ht value at the start of extracorporeal circulation, the aortic cross-clamping time, the total extracorporeal circulation time and total bleeding amount. The following are described in the order of importance. 1) Calculated Ht value: more than 30%. 2) The amount of blood loss after ECC is removed: less than 500 ml. 3) Preoperative body weight: more than 50 kg. 4) Preoperative Ht value: more than 40%. 5) The total ECC time: less than 90 min. In addition, prospective factors which should be considered preoperatively are determined in the following orders. 1) Calculated Ht value. 2) Preoperative Ht value. 3) Preoperative body weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Transfusion↗
PubMed1989

[Aortic dissection associated with percutaneous intra-aortic balloon pumping].

This is a case report of aortic dissection associated with percutaneous intraaortic balloon insertion, which was attempted for systolic unloading after repair of left ventricular rupture. But the hemodynamic condition gradually deteriorated in spite of IABP support and aortic dissection was suspected from the difference between monitoring pressures of bilateral radial arteries and balloon tip. The balloon was removed on the 3rd postoperative day, but the patient died from renal failure, liver dysfunction and D.I.C. on the 7th postoperative day. At postmortem examination, aortic dissection was found, which extended from left common iliac artery, all the way past right renal artery and ended just below origin of left subclavian artery. Therefore, acute renal failure was supposed to be followed by aortic dissection.

Aortic Dissection↗
PubMed1989

[A comment on optimal shaped prosthesis for tricuspid valve using an experimental model].

The prosthesis for mitral valve has been in use instead of the prosthesis for tricuspid valve, since the latter prosthesis has not at present been available. In view of the shape of tricuspid valve, which is essentially flat in form, it is not good for replacing with the prosthesis for mitral valve which has an almost circular shape because of the difficulties in suturing, and many criticisms on this substitution have been raised. In order to obtain more suitable prosthesis as exactly benefits TVR, we have developed at first an instrument indicating the change of cardiac function occurring in the course of fixing the annulus of tricuspid valve that would undergo the difference in shape from circular to flat, using experimental models throughout, which has eventually led to the exploration of the possible exact shape of a prosthesis of the annulus for tricuspid valve. Our series of experiments proved as conclusion that the annulus of tricuspid valve is more advantageous when fixed with an ellipse of a flattened rate 1.6 compared with any circular ones tested. In view of the left ventricular stroke work, it is apparent that a prosthesis for mitral valve which is circular in shape should not be applied. We emphasize that a prosthesis for tricuspid valve which is ellipse in shape with desired flattened rate of 1.6 should be developed for our future applications.

Animals↗
PubMed1989

[Application of a large occlusion balloon catheter to re-do open heart surgery].

A very rare case having re-do open heart surgery four times during two years was reported. The case was 30 year-old-male complicated with aortitis syndrome and underwent mitral valve replacement because of infective endocarditis. But the prosthetic valve repeated detachment over and over again after first MVR in spite of complete treatment of steroid for aortitis syndrome. When fourth re-operation, it was easily expected that median sternotomy, cannulation and clamping would be difficult because of tough adhesion. So large occlusion balloon catheter was used to clamp the ascending aorta and operative field was exposed by left thoracotomy under femoro-femoral bypass. We could accomplish the operative procedure safely under "instrument free" operative field. Large occlusion balloon catheter is very useful for aortic clamping in case of not only reoperation but calcified aorta and so on.

Adult↗
PubMed1988

Inhibition contributes to orientation selectivity in visual cortex of cat.

Neurons in the visual cortex are selectively responsive to light or dark bars presented at particular orientations. On the basis of physiological data, this orientation selectivity is hypothesized as being due at least partially to intracortical inhibitory mechanisms. But this hypothesis has been challenged by intracellular recordings indicating that excitatory inputs themselves are orientation-selective, so inhibition may not contribute to the observed selectivity. Also, there is controversy about the presence of intracortical horizontal connections mediating inhibition for selectivity and about the theoretical validity of such inhibitory connections. Using cross-correlation analysis of the activities of two neurons recorded simultaneously, we find that inhibitory interactions exist between cells with somewhat different, but not orthogonal, orientation preferences. This suggests that intracortical horizontal inhibition operates between 'orientation columns' to sharpen the orientation tuning of cortical neurons.

Action Potentials↗
PubMed1988

Defective estrogen receptors in human mammary cancers: their significance in defining hormone dependence.

Neither estrogen dependence nor clinical response to hormone therapy of the tumor is guaranteed by the mere presence of receptors for estrogens (ERs) or progesterones (PRs). Immunohistochemical staining of ER with polyclonal anti-ER antibodies after in vitro transformation has enabled the identification of two types of defective ER among human breast cancers: those that are unable to bind to the nucleus in a hormone-filled state and those that bind to the nucleus as naked ER. Preliminary clinical correlation studies demonstrate that a subclassification of ER(+) tumors based on functional abnormalities of ER may predict refractoriness to hormone therapy.

Antibodies, Monoclonal↗
PubMed1988

Morphological changes in a human scirrhous gastric carcinoma cell line (KATO-III) when cultured in collagen-coated dishes.

The morphological differences between cells of a human scirrhous gastric carcinoma cell line (KATO-III) cultured in plastic dishes and in collagen-coated dishes were examined by phase-contrast and electron microscopy. When KATO-III cells were inoculated into plastic dishes, a few cells became attached to the surface of the dishes and the rest remained in suspension. However, when they were inoculated into collagen-coated dishes, they all remained in suspension. In both types of dish, most of the cells in suspension were single although a few were in clusters. The cells in suspension in collagen-coated dishes differed in morphology from those in the plastic dishes. They had abundant cytoplasm, well-developed Golgi complexes, and many microvillus-like cell protrusions. Moreover, they had hemidesmosome-like and desmosome-like structures on their surface and an increased amount of intracytoplasmic desmosome-like structures. The cells in clusters in the collagen-coated dishes were closely connected by junctional complexes, such as tight junctions, desmosomes and interdigitations, whereas those in plastic dishes were linked only by desmosomes. These results suggest that collagen affects the morphology of human scirrhous carcinoma cells.

Adenocarcinoma, Scirrhous↗
PubMed1988

Identification of transferrin receptor in cervical and endometrial tissues.

The location of transferrin receptor (Tf.R) which is abundantly contained in proliferating cells and positional relationships of cells containing much Tf.R was observed on cervical and endometrial tissue sections by immunohistochemistry. In normal squamous epithelium, the parabasal cell layer was positive and the basal, intermediate, and superficial cell layers negative. This shows that the cells of the parabasal cell layer are proliferating most actively among those layers. Squamous carcinoma contained many positive cancer cells. But negative as well as positive cells were present, indicating that cancer cells proliferate under various conditions. Cancer cells infiltrating the stroma were made clear by Tf.R staining, and it became easier to identify them when only a few were present. Endometrial glandular cells in the basal layer stained only on the basal side of a cell regardless of the menstrual cycle, whereas in the functional layer glandular lumen side also stained positive in the secretory phase. Based on the present data, an immunohistochemical study of Tf.R seems useful to confirm the localization of proliferating cells and cancer cells and determine the conditions for cancer cell proliferation on the tissue sections.

Carcinoma, Squamous Cell↗
PubMed1988

The effects of vasoactive agents on the proliferation of vascular smooth muscle cells grown in vitro.

The present study was designed to investigate the effect of vasoactive agents on cellular proliferation in serially passed cultured vascular smooth muscle cells (VSMC). A substantial reduction in the number of vascular smooth muscle cells was observed with the addition of nifedipine, nicorandil, bunazocine and labetalol compared with that in a control sample. Furthermore, noradrenaline significantly increased the number of vascular smooth muscle cells. In contrast, neither propranolol nor captopril had any effect on number of vascular smooth muscle cells. The cell size, measured as water volume of vascular smooth muscle cells based on the equilibrium distribution of 3-O-(14C-methyl)-D-glucose, did not differ between treatments with the above-mentioned agents. It is suggested that in addition to a known calcium-mediated mechanism, an alpha-receptor-mediated property could be involved in the proliferation of vascular smooth muscle cells and that clinical use of a calcium antagonist or an alpha-blocker might be useful to prevent the hyperproliferation of vascular smooth muscle cells commonly seen in the vascular walls of patients with hypertension.

Amiloride↗
PubMed1988

A new objective parameter for the electromyographic evaluation of masticatory function of edentulous patients.

An objective parameter for the electromyographic evaluation of the masticatory function of edentulous patients was studied. The normal ranges of the parameters for such subjects were also established. This study focused on the time parameter of electromyography, which is one of the most reproducible parameters. The variation coefficient of the time parameters (interval and duration) were revealed to be reliable and reproducible for the evaluation of masticatory functions.

Aged↗
PubMed1988

The effects of muscle fatigue on the silent period of the masticatory muscles.

Thirteen healthy adults performed sustained clenching at 50% maximum clenching level judged electromyographically. Electromyograms were recorded from both anterior temporal and masseter muscles during clenching and the silent period latency and duration were measured. As the result of muscle fatigue, the silent period latency significantly decreased, whilst the duration significantly increased up to 3 min from the beginning of clenching.

Adult↗