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Biomedical subjects

M Morikawa

Publications and source records attributed to M Morikawa.

At least 181 records · Page 10Linked to original sources
PubMed1992

Partitioning of pulmonary responses to inhaled methacholine in subjects with asymptomatic asthma.

To partition the central and peripheral airway resistance, a catheter-tip micromanometer sensing lateral pressure of the airway was wedged into the right lower lobe of a bronchus with a 3 mm inner diameter in 10 patients with asymptomatic asthma. We simultaneously measured mouth flow, transpulmonary pressure (PL) and intra-airway lateral pressure during tidal breathing. Total pulmonary resistance (RL) was calculated from PL and mouth flow, and central airway resistance (RC) was calculated from intra-airway lateral pressure and mouth flow. Peripheral airway resistance (Rp) was obtained by subtraction of RC from RL. Therefore, our measurement of Rp included lung tissue resistance. The technique permitted identification of the site of changes in airway resistance. The baseline values of resistances were 2.3 +/- 0.2 cm H2O/L/s in RL, 1.5 +/- 0.1 cm H2O/L/s in RC, and 0.8 +/- 0.1 cm H2O/L/s in Rp, respectively. To determine the site of airway hyperresponsiveness, dose-response curves of central, peripheral, and total airways to inhaled methacholine were separately constructed. Bronchial responsiveness was evaluated by a log methacholine unit requiring a 35% decrease (PC35) and a 50% decrease (PC50) in pulmonary conductance (a reciprocal of RL). We calculated the increase of resistances in total (delta RL), central (delta RC), and peripheral (delta Rp) airways from the baseline values at either PC35 or PC50.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[A case report of inverted papilloma of the posterior urethra].

A case of inverted papilloma of the posterior urethra is reported. A 59-year-old male was admitted with the chief complaint of hematuria. Urethrogram revealed a small defect in the neck of the bladder. Endoscopic examination revealed a polypoid tumor on the stalk arising from prostatic urethra, and transurethral resection was performed. The patient has been subsequently followed up and there has been no evidence of recurrence. Although 141 cases of inverted papilloma have been reported in many anatomical sites of the urinary tract, only 19 cases involving the posterior urethra have been described in Japan. This is the 20th case of a posterior urethra.

Humans↗
PubMed1992

[Clinical study of parathyroidectomy of secondary hyperparathyroidism in patients with chronic renal failure].

We performed parathyroidectomy for renal osteodystrophy due to secondary hyperparathyroidism on 16 patients with chronic renal failure who were refractory to medical management; subtotal parathyroidectomy on one patient and total parathyroidectomy with autotransplantation on 15 patients. Postoperative clinical improvement, i.e., bone and/or joint pain, pruritus and radiographic signs of renal osteodystrophy, was marked. After the operation, serum calcium decreased rapidly and adequate calcium replacement therapy was necessary. The levels of intact parathyroid hormone decreased rapidly and serum concentration of alkaline phosphatase gradually decreased for a few months postoperatively. Recurrence was diagnosed in one patient, who underwent excision of the transplanted parathyroid tissue. Osteomalasia due to hypoparathyroidism was not seen clinically in this series. In preoperative image diagnosis, ultrasonotomogram (US) showed the highest detective rate of the enlarged parathyroid glands. However, combination of US, computerized tomography and 99mTcO4(-)-201T1C1 scintigram can be recommended as a localizing diagnostic method for compensating the disadvantages of each method. Clinical results after parathyroidectomy for secondary hyperparathyroidism are considered to be good. However, long-term followup is mandatory for early detection of persistent hyperparathyroidism or hypoparathyroidism.

Adult↗
PubMed1992

[A case of multilocular renal cell carcinoma].

Herein we report case of multilocular cyst of the right kidney complicated with clear cell type renal cell carcinoma. The chief complaint of the 51-year-old male patient was macroscopic hematuria. He underwent radical nephrectomy and was administered postoperative adjuvant chemotherapy with alpha-interferon. No recurrence was found 18 months after operation. Pathogenesis of multilocular cyst of the kidney and the mechanism of malignant transformation are discussed.

Carcinoma, Renal Cell↗
PubMed1991

[Bile lake: a complication of transcatheter hepatic arterial infusion and embolization therapy (TAI, TAE)].

A 74-year-old man with hepatocellular carcinoma developed cholangitis and bile lake in the liver after repeated TAI (anticancer drug-lipiodol suspension) and gelfoam TAE. Despite percutaneous transhepatic drainage, he died of hepatic failure 34 months after the first TAI and TAE. We speculate that cholangitis and bile lake were caused by chemical toxicity of highly concentrated anticancer drug to the bile duct and compression of the proximal bile duct by the tumor.

Aged↗
PubMed1991

The inhibitory action of okadaic acid on mechanical responses in guinea-pig vas deferens.

Okadaic acid and nifedipine inhibited contractions induced by noradrenaline (NA), KCl and ATP in guinea-pig vas deferens. NA, KCl and ATP induced initial spike-like changes followed by a sustained increase in cytosolic Ca2+ levels ([Ca2+]cyt) and tension. Okadaic acid inhibited the sustained increments in [Ca2+]cyt and muscle tension due to NA and ATP more than the initial spike-like changes, whereas nifedipine more strongly inhibited the initial spike changes. Okadaic acid also inhibited the KCl-induced contraction with only a small inhibition of the stimulated [Ca2+]cyt. By contrast, nifedipine (10(-7) M) inhibited the increments in both [Ca2+]cyt and muscle tension due to KCl. Okadaic acid markedly inhibited the maximal contractile response to Bay K 8644 but nifedipine only shifted the response curve to the right without affecting the maximum responses. In a Ca2(+)-free medium containing EGTA and nifedipine, okadaic acid did not inhibit the residual phasic contractile response to NA (10(-4) M) but the contractile response to a subsequent addition of Ca2+ (1.2 mM) was suppressed. These results suggest that, in guinea-pig vas deferens, okadaic acid has an inhibitory effect on smooth muscle contraction but not on the intracellular Ca2+ mobilization. The inhibitory effect may be due to the inhibition of Ca2+ influx and the possible interference of contractile elements.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1991

Expression of src family genes during monocytic differentiation of HL-60 cells.

It has been reported that src family protein-tyrosine kinases were expressed specifically in a certain lineage or differentiation stage of hematopoietic cells. To understand the molecular basis for differentiation and function of monocyte/macrophage, we investigated the expressions of src family genes by the HL-60 cells stimulated with differentiation-inducing agents. TPA and vitamin D3 (D3) were used as stimulants for monocytic development, since each agent has been known to induce phenotypically specific differentiation of HL-60 cells. The fyn, fgr, and lyn genes were characteristically expressed concomitantly with phenotypic changes and expressions of nuclear proto-oncogenes, whereas src, lck, hck, and yes genes were not. In TPA-induced differentiation of HL-60 cells, both fyn and lyn genes, but not fgr gene, were expressed. In contrast, both fgr and lyn genes, but not fyn gene, were expressed in D3-induced differentiation of the cells. The independent and characteristic expressions of these genes were observed in the further advanced differentiation of HL-60 cells induced by TPA plus D3 or D3 plus human transforming growth factor-beta 1. The granulocytic differentiation of the cells treated with retinoic acid was accompanied by intense expression of fgr, but weak or no expression of lyn and fyn gene. These data indicate that each protein-tyrosine kinase encoded by src family genes may play distinct roles in development and/or functions of monocyte/macrophage-lineage cells.

Calcitriol↗
PubMed1991

Magnetic resonance imaging of cerebral fat embolism.

The cerebral fat embolism is a potentially serious complication of fractures but clinical cases often go undiagnosed. Two cases of clinically diagnosed cerebral fat embolism are reported, and MR images of these patients are described. While brain CT revealed no abnormality, MR imaging showed relative low-intensity areas on T1-weighted images and high-intensity areas on T2-weighted images. In one patient follow-up MR showed nearly complete resolution of the abnormal signal. MR imaging appears to be valuable for detecting the lesions in these patients.

Adolescent↗
PubMed1991

Effects of the mammalian lignan, 2,3-dibenzyl-butane-1,4-diol, on contraction and Ca2+ mobilization induced by noradrenaline in rat aorta.

1. In rat aorta, 2,3-dibenzylbutane-1,4-diol (DBB) inhibited noradrenaline (NA)-induced contraction in a concentration-dependent manner. The inhibitory effect of DBB was observed in verapamil-pretreated muscle, and did not differ from that in the high K+ solution containing verapamil (1.0 microM). 2. DBB inhibited not only contraction, but [Ca2+]i elevation induced by NA (10 microM) with the same potency. 3. The inhibitory effect of DBB on NA-induced contraction was reversed by methylene blue (3.2 microM) and enhanced by M&B 22,948 (10 microM). 4. DBB (100 microM) alone increased cyclic GMP levels. This effect was attenuated by methylene blue (3.2 microM) and augmented by M&B 22,948 (10 microM). 5. From these results, the inhibitory effects of DBB on NA-induced contraction in rat aorta may be caused by an increase of cyclic GMP levels.

Animals↗
PubMed1991

Functional analysis of HLA-DR-expressing keratinocytes from tuberculin reactive skin.

We examined the functional roles of HLA-DR+ keratinocytes which were induced in vivo from tuberculin reactive skin. At 4 days after intradermal PPD injection, about 80% of keratinocytes obtained from the tuberculin reactive area expressed DR antigens. In 14 of 18 individuals examined, PPD-pulsed DR+ keratinocyte fraction induced autologous T-cell proliferation. The proliferative response was PPD-dependent, antigen specific; it depended upon DR expression by the keratinocyte fraction, because it did not occur in the presence of the PPD-nonpulsed DR+ keratinocyte fraction and was completely blocked by mouse monoclonal antibody to HLA-DR. However, the antigen-presenting capacity of the DR+ keratinocyte fraction appeared to be less than that of monocytes or the DR+ epidermal cell fraction. The DR+ keratinocyte fraction was also able to stimulate allogeneic T-cell DNA synthesis, but the DR- keratinocyte fraction could not. The possible influences of contaminant Langerhans cells and mononuclear cells in the DR+ keratinocyte fraction were considered to be unlikely. These results suggest that DR+ keratinocytes, which are induced in vivo, can both present the antigen to autologous T cells and stimulate allogeneic T cells.

Cell Division↗
PubMed1991

Positive inotropic action of veratridine in rat atria: possible involvement of prostanoids.

Veratridine caused a positive inotropic action in the electrically driven left atria of rats. Quinacrine (a phospholipase A2 inhibitor), indomethacin (a cyclooxygenase inhibitor) and aspirin (a cyclooxygenase inhibitor), but not nordihydroguaiaretic acid (a lipoxygenase inhibitor), inhibited the response to veratridine. Verapamil and nifedipine also inhibited the response to veratridine. The positive inotropic effect of arachidonic acid was abolished by aspirin and indomethacin. However, the positive inotropic effect of PGF2 alpha was not affected by indomethacin, quinacrine or aspirin. PGE2, but not STA2 and PGI2, also caused the positive inotropic effect. However, the negative inotropic effect was observed in the presence of PGE1 and PGD2. Veratridine shifted the concentration-response curve of Ca2+ to the left in a Ca(2+)-free medium. Indomethacin only inhibited the veratridine-induced potentiation of Ca2+ responses. Veratridine increased the level of PGF2 alpha in the left atria and this action was completely inhibited by indomethacin, aspirin and quinacrine. Veratridine also increased the level of PGE2. These results imply that the positive inotropic action of veratridine is partly due to stimulation of the release of arachidonic acid leading to the increase in prostaglandins in rat atria.

Animals↗
PubMed1991

Activity of artificial mutant variants of human growth hormone deficient in a disulfide bond between Cys53 and Cys165.

In order to understand the role of Cys53 and Cys165 of human growth hormone (hGH) in receptor-binding and biological activity, artificial mutant variants of hGH were prepared in Escherichia coli by in vitro mutagenesis. Variants of hGH were constructed by replacement of Cys165 with Ala ([Ala165]hGH) or Ser ([Ser165]hGH), by replacement of Cys53 with Ala ([Ala53]hGH), by replacement of Cys53 and Cys165 with Ala ([Ala53, Ala165]hGH), or by replacement of Cys53 with Ala and Cys165 with Ser ([Ala53,Ser165]hGH). All of the variants constructed as well as reduced hGH exhibited less biological activity than that of intact hGH, and the decreases in biological activity were almost equal, as measured by a sensitive biological assay for growth hormone: adipose conversion assay using 3T3-F442A cells. These variants also showed less receptor-binding activity than that of intact hGH. These results suggest that it is possible neither the residue Cys53 nor Cys165 is directly involved in the receptor binding, and that the disulfide bridge between Cys53 and Cys165 in hGH may not always be crucial for the biological activity, though necessary to express full hGH activity.

Animals↗
PubMed1991

[Percutaneous management of benign ureteroileal anastomotic strictures after ileal conduit urinary diversion].

We report our experience with the endourological treatment of 4 patients with 5 benign ureteroileal anastomotic strictures after ileal conduit urinary diversion. The treatment was successful in 4 of the 5 renal units without restenosis with a mean follow up of 10 months. The strictures were dilated by ureteral dilators and/or balloon dilation catheters using guide wires through percutaneous nephrostomies in an antegrade fashion. A 9 or 12 Fr. percutaneous splint catheter or a 12 Fr. double pig tail catheter was placed for 3-8 weeks after a successful dilation. Two renal units underwent repeated dilations. In 1 renal unit, a guide wire was hardly passed through the stricture and the treatment was unsuccessful. No serious complications were encountered. Percutaneous endourological managements of ureteroileal anastomotic strictures seemed to be quite versatile techniques which should be tried as the initial approach in many cases.

Anastomosis, Surgical↗
PubMed1991

[Comparative analysis of Hancock and St. Jude Medical valve after mitral valve replacement].

Long term results were compared in 81 operative survivors with MVR using Hancock valve (Hancock group) and 83 using St. Jude Medical valve (SJM group). The cumulative follow-up was 709.0 patients-year (p-y) and 175.2 p-y in the Hancock and SJM groups. Twenty-four percent of the patients in the Hancock group was permanently anticoagulated, while 100% of patients in the SJM group anticoagulated. The 7-year actuarial survival rate including early mortality was 79.3 +/- 4.6% for the Hancock and 93.9 +/- 3.0% for the SJM group (p less than 0.01). The survival rate was significantly higher in the SJM group than that in the Hancock group. The 7-year actuarial event free rate of the valve-related complications in the Hancock and SJM groups were as follows; thromboembolism 88.6 +/- 3.8% vs 95.0 +/- 2.8% (NS), hemorrhage, 94.0 +/- 3.0% vs 98.7 +/- 1.8% (NS), paravalvular leak 92.6 +/- 3.2% vs 97.4 +/- 1.8% (NS), infection 93.9 +/- 3.0% vs 100% (p less than 0.05), valve malfunction 78.0 +/- 5.2% vs 100% (p less than 0.001), overall valve related complications 58.9 +/- 5.9% vs 91.1 +/- 3.5% (p less than 0.001), reoperation for valve-related complication 83.1 +/- 4.6% vs 100% (p less than 0.01). The event free rate of reoperation for valve related complication in the Hancock group was significantly lower than that in the SJM group. The Hancock valve had the acceptable antithrombogenicity, but had the limited long-term durability.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Effects of combination therapy with low-dose aspirin and warfarin on platelet functions after heart valve replacement.

To evaluate the efficacy and safety of combination therapy with aspirin and warfarin for preventing the development of thromboembolism, we compared the effects of low-dose aspirin (81 mg/day) on platelet functions to those of ticlopidine (300 mg/day) in heart valve replacement patients. Experiments were performed in two groups; the first group within 1 month after operation (the unstable period) and the second group between 3 months and 3 years after operation (the stable period). At the stable period, low-dose aspirin inhibited platelet aggregation induced by ADP, collagen, or arachidonic acid, and suppressed the increase in intracellular Ca2+ concentration [( Ca2+]i) induced by thrombin significantly. On the other hand, ticlopidine inhibited platelet aggregation induced by ADP or collagen, but did not suppress arachidonic acid-induced aggregation and the thrombin-induced [Ca2+]i increase. At the unstable period, the combination therapy of low-dose aspirin plus warfarin did not prolong the bleeding time compared to ticlopidine plus warfarin. And low-dose aspirin inhibited platelet aggregation induced by ADP, collagen or epinephrine, and especially blocked arachidonic acid-induced aggregation. Ticlopidine inhibited ADP-, collagen- or U-46619-induced aggregation, but did not affect on the increase in [Ca2+]i induced by thrombin. From the results in this study, we suggest that the combination therapy with low-dose aspirin (81 mg/day) and warfarin is safe as an antithrombotic medication in heart valve replacement, and results in the inhibition of platelet functions without any side effect calling for special mention at the early unstable period after operation.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1991

[Reoperation of primary tissue failure of bioprosthesis in the mitral position].

The surgical results of 38 patients who underwent reoperation for primary tissue failure of bioprosthesis in the mitral position between May 1982 and June 1990 were analyzed to determine the risk factors affecting the hospital mortality. The type of bioprostheses requiring reoperation were Hancock valve in 21 patients, Liotta valve in 15 patients and Mitroflow valve in 2 patients. Twenty-five preoperative and perioperative variables were collected and analyzed by univariate statistics using chi 2 test or Student's test. Four of thirty eight patients died postoperatively in the hospital, yielding an overall mortality of 10.5%. The causes of hospital mortality were low output syndrome in 2 patients and multiple organ failure in 2 patients. By univariate analysis, male, NYHA IV class, prosthetic stenosis, hepatic failure, renal failure, and pulmonary failure were risk factors predictive of high hospital mortality. In spite of recent improvement of surgical technique and myocardial protection, the hospital mortality of patients with NYHA IV class and advanced organ failure still remains unacceptable. Therefore, it is essential to perform reoperation for primary tissue failure of bioprosthesis before severe myocardial decompensation occurs. To accomplish this goal, patients with bioprosthesis who survived beyond the certain time should be followed periodically using echocardiogram.

Adult↗
PubMed1990

An active site of growth hormone for eliciting the differentiation of preadipose 3T3-F442A cells to adipose cells.

In order to elucidate the active sites of growth hormone for eliciting the differentiation of preadipose 3T3-F442A cells to adipocytes, four artificial mutant variants of human growth hormone (hGH) modified in the loop region of amino acid residues 54-74 were prepared in Escherichia coli by site-directed mutagenesis. Although the P59A (replacement of Pro59 with Ala) variant retained almost the same biological- and receptor binding-activity as hGH, the P61A (replacement of Pro61 with Ala) and the P59A-P61A (replacement of both Pro59 and Pro61 with Ala) both exhibited about half the activity, and the delta (62-67) variant (deletion of the residues 62-67) exhibited only about 0.1% the activity of those of intact hGH. The results suggest that Pro61 may be involved in formation of the active conformation of hGH, but Pro59 may not, and that the amino acid residues around 62-67 may be critical for the specific biological features of hGH.

Adipose Tissue↗