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Biomedical subjects

S Miyazaki

Publications and source records attributed to S Miyazaki.

At least 577 records · Page 32Linked to original sources
PubMed1990

Axoplasmic electrolyte contents measured by X-ray microanalysis in experimental uremic neuropathy.

We investigated the mechanism of uremic neuropathy using experimental acute and chronic renal failure models in rats. After induction of renal failure, the motor nerve conduction velocity, axoplasmic electrolyte content, and cross-sectional area of myelinated fibers in the sciatic nerve were determined. The axoplasmic Na, K, Cl, and Ca contents were measured by electron probe X-ray microanalysis employing with sections from freshly freeze-dried sciatic nerves. The results obtained for both the acute and chronic renal failure models were similar. The sciatic motor nerve conduction velocity was significantly decreased in both cases as compared to that in the controls. The sciatic nerve axoplasmic Na content was significantly lower than that of the controls in both acute and chronic renal failure, and a significant reduction in the cross-sectional area of the myelinated fibers was observed in both renal failure models. These results suggest that impairment of the axonal membrane Na permeability and shrinkage of the myelinated fibers may play an important role in the decrease of motor nerve conduction velocity in uremic neuropathy.

Acute Kidney Injury↗
PubMed1990

[A case of progressive systemic sclerosis associated with a hemorrhagic infarction of the cerebellum].

Central nervous system is rarely involved in progressive systemic sclerosis (PSS) unless there are concomitant abnormalities in renal or lung function or hypertension. A 72-year-old woman with typical PSS developed cerebellar bleeding. Medical history records revealed, she had noted the onset of Raynaud's sign on her upper extremities at the age of 37. This was followed by necrosis and repeated infection, and as a result, shortening of her fingers in her 40's. The disease progressed and involved lower extremities, and then face and body in her 50's. Aortic valve stenosis was diagnosed at 69 year old, cardiac myopathy at 70 and at the age of 71 infectious dermatitis in both inguinal regions. Mild anemia, hypoalbuminemia and the decrease of serum Fe were discovered in June 1988. At the same time, prolonged ESR, positive C-reactive protein, RA, and anti-nuclear-antibody were also noticed. A chest roentgenogram revealed pulmonary fibrosis. Systemic hypertension was not noticed on the clinical course. She developed an onset of vertigo and vomiting in the morning of August 8, 1988. Consequently, she was brought to our hospital. She was alert but a physical examination showed a swallowing disturbance, dysarthria, right cerebellar ataxia, nystagmus and hypertension (192/100 mmHg). A CT examination on admission revealed a slightly low density area in right cerebellar hemisphere without mass effect. She was treated with dextran and mannitol and her condition improved on the 6th day of her admission. She was alert and blood pressure calm down to 120/70 mmHg without the use of anti-hypertension drugs on August 21.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Evidence for an inhibitory effect of protein kinase C on G-protein-mediated repetitive calcium transients in hamster eggs.

Hamster eggs undergo repetitive increases in cytoplasmic free calcium concentration ([Ca2+]i) at fertilization or after injecting guanosine-5'-0-(3-thiotriphosphate) (GTP[S]). We report the effects of protein kinase C (PKC) agonists and antagonists on these repetitive [Ca2+]i transients as measured by their associated membrane potential hyperpolarizing responses (HRs). Iontophoretic injection of GTP[S] into unfertilized eggs caused a series of repetitive HRs that declined in amplitude with time. Continuous injection of inositol 1,4,5-trisphosphate (InsP3) also caused a series of repetitive HRs, but these HRs declined in amplitude less markedly. GTP[S]-induced HRs were inhibited by the PKC agonists phorbol 12-myristate 13-acetate (TPA) (100 nM) and 1,2-dioctanoyl-glycerol (diC8) (250 microM). Conversely the PKC inhibitor sphingosine (10 microM) enhanced the number of large HRs after GTP[S] injection. TPA or sphingosine did not alter InsP3-induced HRs. We suggest that G-protein-mediated InsP3 production causes repetitive [Ca2+]i transients but that GTP[S] injection stimulates a negative feedback loop involving PKC. Adding TPA (100 nM) before insemination caused a reduction in the frequency of HRs at fertilization, but neither TPA nor sphingosine affected the frequency or size of HRs when they were added after the start of fertilization. Fertilizing sperm may stimulate G-protein-mediated InsP3 production in a way that precludes feedback inhibition by PKC.

Animals↗
PubMed1989

Proteinic prorenin-releasing-stimulator (PRS) in the rat submandibular gland.

The release of prorenin as well as renin from rat renal slices was confirmed by a rat prorenin-prosegment ELISA system and an assay system for determining the renin activity. A significant increase of the prorenin release was found by adding rat submandibular gland extract to the slice medium, indicating the existence of a prorenin-releasing stimulator (PRS) in the extract. The pI and molecular mass of PRS were 8.5-8.7 and 28-30 kDa, respectively. The PRS was completely inactivated by boiling or a proteinase treatment.

Animals↗
PubMed1989

Increased furosemide-sensitive sodium influx into erythrocytes in non-insulin-dependent diabetes mellitus associated with hypertension.

Our previous study demonstrated increased sodium (Na+) influx into ouabain-treated erythrocytes in diabetic patients with hypertension. The present study was designed to estimate the effect of furosemide on the Na+ influx in non-insulin-dependent diabetes mellitus (NIDDM) with hypertension. Both Na+ influx in the absence of furosemide (total Na+ influx; TNaI) and furosemide-sensitive Na+ influx (FSNaI) were increased in patients with essential hypertension (group 1, n = 22) than those in non-diabetic, normotensive control subjects without family history of hypertension (control group, n = 26, P less than 0.001 and P less than 0.001, respectively). TNaI and FSNaI in diabetic patients without hypertension (group 2, n = 28) were also higher than those in the control group (P less than 0.02 and P less than 0.001, respectively), but no significant differences were found in TNaI or FSNaI between groups 1 and 2. TNaI and FSNaI in diabetic patients with hypertension (group 3, n = 19) were elevated than those in control group (P less than 0.001 and P less than 0.001, respectively), in group 1 (P less than 0.05 and P less than 0.02, respectively) and in group 2 (P less than 0.001 and P less than 0.001, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Acceleration of cell necrosis following reperfusion after ischemia in the pig heart without collateral circulation.

A study of whether reperfusion accelerates cell death was performed in 35 pig hearts without collateral circulation. In 15 animals, the distal one-third of the left anterior descending coronary artery was occluded for 1 hour followed by 1-, 3-, or 7-hour reperfusion in 5 animals each. As controls, 5 hearts each were examined after 1, 2, 4 and 8 hours of occlusion of the artery without reperfusion. Heart rate and aortic pressure before and during occlusion and reperfusion did not change in any group. The subepicardial and subendocardial regional blood flow decreased to almost zero in all hearts after occlusion (85 +/- 1 to 2 +/- 2) but recovered during reperfusion (65 +/- 15 ml/100 g/min). Specimens were histologically examined by an enzyme method using nitrotetrazolium blue, an immunohistochemical method using myoglobin antibody, by staining with hematoxylin-eosin and Masson's trichrome. In the control hearts, clear demarcation of the infarct area was observed 4 hours after occlusion. However, in the reperfusion group, clear demarcation of the infarct was seen after 1-hour reperfusion, namely, 2 hours after the onset of infarct. Demarcation was seen not only in the tissue with contraction band necrosis, but also in the tissue with coagulation necrosis. Therefore, it is concluded that reperfusion accelerates cell death due to both contraction band necrosis and coagulation necrosis.

Animals↗
PubMed1989

Long-term follow-up study of children with chronic ITP.

A total of 126 children with chronic idiopathic thrombocytopenic purpura, including 35 splenectomized cases, were investigated in a long-term follow-up study, with regard to residual hematologic and immunologic abnormalities, complications and physical growth. Such hemorrhagic symptoms as petechiae, ecchymosis and epistaxis were still observed in about 22%-28% of the patients with a period of morbidity ranging from 3 to 15 years after onset. Residual thrombocytopenia below 150,000/microliters was found in 62% of patients within 5 years, 59% within 5 to 9 years and 57% within 10-14 years after onset. Other abnormalities were mild anemia, low serum level of IgA or IgM, positive antinuclear antibody, rheumatoid factor, and positive Coombs test in a small number of patients. Increased platelet-associated IgG was still obtained in patients with subnormal platelet counts whose morbid periods were 6 to 27 years after onset. Investigation of the patients by questionnaire revealed such complications as obesity, striae atrophicae, abdominal pain, headache, cataract, Perthes' disease, and cardiac complication in some patients. No apparent disturbances except for obesity were observed in their physical growth.

Autoimmune Diseases↗
PubMed1989

Endoscopic clip-marking of lesions using the newly developed HX-3L clip.

Injection of India ink and clipping are relatively well-known methods for marking lesions of the gastrointestinal tract. The use of metal clips provides a radiologically recognizable mark, which is also palpable at surgery. In addition, clips can be extremely useful as landmarks in comparing endoscopic findings with the resected specimen. Previous reports of clip-marking have concentrated on the Olympus (Tokyo, Japan) HX-2L clip, but this clip has the disadvantages of having too wide a diameter to be used through most conventional endoscopes and also a relatively low clip-retention rate, as the depth of its bite is limited. Recently, Olympus has marketed a new clip (HX-3L) designed by the author for hemostasis in cases of gastrointestinal bleeding. This new clip is an improved version of the cassette-type J-clip that was previously reported by the author in this journal. The prime advantage of the HX-3L is that the endoscopist can use it via a panendoscope without any assistance. In addition, it has an excellent bite and a very high level of safety. In terms of function and application, it is completely different from the HX-2L. In addition, the tip (the portion that actually grasps tissue) of the HX-3L is longer and thinner than the HX-2L, thus permitting a firm grasp of the muscularis mucosae layer even when approaching from an upper oblique angle and this, in turn, improves the performance of the clip as a marker.(ABSTRACT TRUNCATED AT 250 WORDS)

Digestive System↗
PubMed1989

A case of multiple infantile fibromatosis of unclassified type.

We report an unusual case of fibromatous disease in infancy, diagnosed as a multiple infantile fibromatosis of unclassified type. Histologically, the tumors are composed of a mixture of fibrous component and mature adipose tissue. The clinical manifestations resemble those of infantile myofibromatosis. The symptoms, including size and number of tumors, have not been progressive for one year.

Female↗
PubMed1989

Selective removal of triglyceride-rich lipoproteins by plasmapheresis in diabetic patients with severe hypertriglyceridemia.

Two diabetic patients with marked intractable hypertriglyceridemia under treatment with hemodialysis for chronic renal failure were treated by either an apolipoprotein B-dependent removal of lipoproteins using dextran sulfate cellulose column plasmapheresis or a size-dependent removal of lipoproteins using hollow-fiber filtration plasmapheresis. In one patient, a column packed with hollow fibers was used as a plasma separator and a dextran sulfate cellulose column as an adsorbent. In another patient, because the hollow-fiber column did not separate plasma from whole blood, a centrifuge-type blood cell separator was used for the plasma separation. The amounts of plasma cholesterol, triglycerides, and phospholipids removed by plasmapheresis were 30%, 33%, and 30%, respectively, when the combination of a hollow-fiber column and a dextran sulfate cellulose column was used. Corresponding values were 31%, 29%, and 27%, respectively, when the combination of the centrifuge-type blood cell separator and the hollow-fiber column was used. The efficiency of lipid removal was almost the same with both techniques. As for plasma separation, the centrifuge-type blood cell separator was more efficient than the hollow-fiber column. Some losses of albumin and platelets were observed when combination plasmapheresis using the centrifuge-type blood cell separator and the hollow-fiber column was performed. In conclusion, we prefer the centrifuge-type blood cell separator to the hollow-fiber column for plasma separation of marked hypertriglyceridemia. The second filter must be chosen for each patient according to the size of the lipoproteins.

Adult↗
PubMed1989

Mechanisms of improved ischemic regional dysfunction by bradycardia. Studies on UL-FS 49 in swine.

In anesthetized swine, the left anterior descending coronary artery was cannulated and perfused at constant blood flow levels during two grades of ischemia. In one group (n = 10), moderate ischemia reduced percent systolic wall thickening (by sonomicrometry) from 25 +/- 7% to 6 +/- 2%, whereas in the other group (n = 7), severe ischemia reduced percent wall thickening from 24 +/- 6% to -0.5 +/- 4%. Heart rate was paced in both groups at 91 beats/min. After reperfusion and complete return to control conditions, administration of the bradycardic agent UL-FS 49 (0.37 mg/kg i.v.) decreased the heart rate to 55 +/- 5 beats/min. During subsequent ischemia at the same coronary inflow as before bradycardia, percent wall thickening in the ischemic zone during moderate ischemia was increased from 6 +/- 2% to 25 +/- 6% (p less than 0.01) (not significantly different from control without ischemia), and during severe ischemia, percent wall thickening increased from -0.5 +/- 4% to 13 +/- 7% (p less than 0.01). During moderate ischemia, bradycardia caused an increase in the subendocardial blood flow from 0.24 +/- 0.60 to 0.42 +/- 0.17 (ml/min)/g (p less than 0.009) and during severe ischemia, bradycardia caused an increase from 0.14 +/- 0.08 to 0.2 +/- 0.1 (ml/min)/g (p less than 0.001). At each level of ischemia, a more marked improvement occurred in subendocardial blood flow per beat ([(ml/min)/g]/heart rate). The relation between myocardial blood flow and wall function at a heart rate of 55 beats/min (n = 14) was plotted and compared with that studied at a heart rate of 122 beats/min in another group of pigs (n = 14). The increase in subendocardial blood flow per minute during bradycardia was not sufficient to explain the striking increase in function; thus, an independent relation (p less than 0.05) between blood flow per minute and contractile function (percent wall thickening) was found for for each heart rate. In contrast, when myocardial blood flow was normalized for heart rate and expressed per beat, data from both heart rate groups could be described by a single relation. Thus, the subendocardial blood flow per beat predicted wall function independently of heart rate and accounted for changes in both oxygen supply and demand.

Animals↗
PubMed1989

Consequences of regional inotropic stimulation of ischemic myocardium on regional myocardial blood flow and function in anesthetized swine.

Determination of the effect of inotropic stimulation on regionally ischemic and hypokinetic myocardium is complicated when intravenous administration of the inotropic agent also causes stimulation of nonischemic adjacent and distant regions, thereby altering global ventricular hemodynamics. To obviate such events, 16 anesthetized swine were studied during regional inotropic stimulation by infusion of dobutamine hydrochloride (2.5 +/- 1 microgram/min) into the cannulated left anterior descending coronary artery. Coronary inflow was controlled by a pump in an extracorporeal circuit. Two groups of swine with different degrees of ischemia were studied. In the first group of animals (n = 8), reduction in coronary inflow to produce a fall in coronary artery pressure (CAP) from 114 +/- 7 mm Hg to 62 +/- 2 mm Hg caused a decrease in percent systolic wall thickening (%WTh) from 34.6 +/- 8.1% to 25.4 +/- 5.8% (p less than 0.005). In the second group of animals (n = 8), CAP was decreased to 46 +/- 5 mm Hg (control: 115 +/- 8 mm Hg) and % WTh decreased from 34.1 +/- 16.4% to 10.4 +/- 6.9% (p less than 0.001). Subendocardial blood flow was reduced from 1.41 +/- 0.38 ml/min/g to 0.65 +/- 0.13 ml/min/g (group 1, p less than 0.001) and from 1.08 +/- 0.22 ml/min/g to 0.24 +/- 0.08 ml/min/g (group 2, p less than 0.001). Regional infusion of dobutamine caused asynchronous ventricular contraction with early systolic augmentation in wall thickening followed by late systolic thinning. Therefore, during hypoperfusion regional myocardial function assessed by %WTh remained unchanged (26.2 +/- 5.8%, p = NS) in group 1 and decreased significantly to 1.6 +/- 5.1% (p less than 0.041) in group 2. Subendocardial blood flow decreased to 0.44 +/- 0.15 ml/min/g in group 1 (p less than 0.005) and to 0.15 +/- 0.07 ml/min/g in group 2 (p less than 0.012). To account for the augmented early systolic thickening that occurred during asynchronous contraction, a myocardial work index was developed in which the sum of the instantaneous left ventricular pressure-wall thickness product was calculated for estimation of regional myocardial work. Increases in this work index were apparent with the addition of dobutamine at both levels of hypoperfusion. This significant enhancement in regional myocardial function in group 2 caused a significant increase of 16% (p less than 0.009) in overall left ventricular power during ejection. Thus, regional inotropic stimulation with dobutamine caused enhancement of maximum work of the ischemic myocardium in the steady state despite a further decrease in subendocardial blood flow.

Animals↗
PubMed1989

External control of drug release. IV. Controlled release of 5-fluorouracil from a hydrophilic polymer matrix by microwave irradiation.

A polymeric system capable of delivering 5-fluorouracil (5-FU) at increased rates on demand by external microwave irradiation was developed. Sustained-release systems were made by incorporating 5-FU into an ethylene-vinyl alcohol copolymer. When exposed to release medium, the delivery systems released the drug slowly and continuously. Upon exposure to microwave irradiation, the drug was released at a much higher rate. Release rates returned to base line levels when the microwave irradiation was discontinued. This study demonstrated that release rates of 5-FU from a polymer matrix can be increased at desired times by external microwave irradiation.

Chemistry, Pharmaceutical↗
PubMed1989

[Results of microvascular decompression in 16 cases of glossopharyngeal neuralgia].

Seven males and nine females with glossopharyngeal neuralgia were treated by microvascular decompression (MVD) over a 4-year period. Their ages ranged from 40 to 72 years (average, 54.7 years). The duration of pain ranged from 2 months to 13 years, and all except one patient had brief attacks of lancinating pain in the throat and/or ear. One patient reported dull, paroxysmal throat pain. At surgery, vascular compression of the 9th and 10th nerves at the root entry-exit zone was observed in all cases. The offending vessels were the posterior inferior cerebellar artery (PICA) in 11 cases, the PICA and the anterior inferior cerebellar artery (AICA) in two, the PICA and vertebral artery (VA), and AICA and VA in one case each. The patient with atypical pain had compression by a large vein. In 15 cases of arterial compression, the pain completely disappeared after MVD, and there was no recurrence during the follow-up period, which ranged from 1 month to 4 years. One patient with venous compression had significant pain relief, although mild throat pain persists. In one case, postoperative complications included transient 6th, 7th, and 10th nerve palsies and sensory disturbance, which were assumed to be due to disturbance of the circulation in the perforating branches from the compressing artery. The experience with these 16 patients indicates that vascular compression is the etiology of glossopharyngeal neuralgia and that MVD provides excellent results.

Adult↗