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Biomedical subjects

F Nakamura

Publications and source records attributed to F Nakamura.

At least 199 records · Page 11Linked to original sources
PubMed1990

Isolation and characterization of new cross-linking amino acid "allodesmosine" from hydrolysate of elastin.

A new pentafunctional cross-linking amino acid, termed allodesmosine, was isolated from bovine ligamentum nuchae elastin. This compound was a very hygroscopic, white amorphous solid with a faint yellow tinge, soluble in aqueous solvents but not dry methanol; it was characterized by UV, FAB mass and NMR spectroscopy. The compound was shown by UV and 1H-NMR to have a pyridinium ring structure similar to desmosine. Mass spectral analysis indicated a parent compound with a mass of 655. We postulated that it arose by condensation of a reduced aldol condensation product of allysine, allysine and lysine.

Amino Acids↗
PubMed1990

[A case of recessive dystrophic epidermolysis bullosa associated with dwarfism with special reference to pathophysiological role of growth hormone].

Epidermolysis bullosa is a group of disorders whose common primary feature is the formation of blisters following trivial trauma. Recessive dystrophic epidermolysis bullosa (RDEB), a subtype of epidermolysis bullosa, is frequently associated with growth retardation. This growth retardation has been reported to be caused by trophopathy following protein loss through skin lesions. Endocrine disorders as the cause of growth retardation in RDEB have not been clearly described. An 11-year-old female had a typical RDEB with dwarfism. Her height was 125 cm and weight was 21 kg, both of which were 2.5 SD below the average. The skin lesions were generalized and probably caused by undernourishment, infection, and blood loss through the skin. However, her serum albumin was at the lower normal limit, and the rapid turnover proteins were slightly decreased. Endocrinological examinations revealed that all the basal levels of pituitary, thyroid, and adrenal hormones were normal. Results of the exercise test, the insulin tolerance test, and the growth hormone-releasing factor test indicated the presence of hypothalamic disorder in secretion of growth hormone. This is the first report of RDEB in which hypothalamic disorder in growth hormone secretion was investigated. On the other hand, growth hormone is known to be involved in collagen metabolism, and a decrease in collagen fibrils and an increase in collagenase activities are found in the skin of RDEB. This implies that this hypothalamic disorder in growth hormone secretion may be involved in the pathophysiology of both dwarfism and the skin lesions in RDEB.

Child↗
PubMed1990

Percutaneous fiberoptic angioscopy of the left ventricle in patients with dilated cardiomyopathy and acute myocarditis.

Left ventricular luminal changes were examined by percutaneous fiberoptic angioscopy in 13 patients with dilated cardiomyopathy and in four patients with acute myocarditis. Angioscope-guided endomyocardial biopsy was also performed in six patients with dilated cardiomyopathy and in two with acute myocarditis. A balloon-tipped guiding catheter (9F) was introduced through the right femoral artery into the left ventricle, the balloon was inflated, and a 1.6 or 4.3F fiberscope was introduced through the catheter into the ventricle so as to locate the fiberscope tip at the tip of the catheter shaft. The balloon was then pushed against the desired portion of the ventricle and warmed saline was infused to observe the luminal changes. In contrast to the patients without organic heart disease whose left ventricular luminal surface was brown in color, the luminal surface was white or light yellow in four, light brown in one, bluish-white in one, with white and brown portions distributed in a mosaic pattern in four, and it was reddish brown in the remaining one patient with dilated cardiomyopathy. Mural thrombi were observed in two of the patients. The luminal surface was light brown in one, reddish brown in one, rose in one, and red in one patient with acute myocarditis. Thrombi and scattered bleeding were observed in two and one of these patients, respectively. The changes in luminal coloration in patients with dilated cardiomyopathy and acute myocarditis had no obvious relation to left ventricular volume and ejection fraction. Angioscope-guided biopsy revealed that the white and light yellow portions were due to endocardial fibrosis, that the endocardia of brown portions were not fibrotic, and that the myocardium in the red portions contained mononuclear cells, indicating inflammation. The results indicate that the angioscopic features of the left ventricular luminal surface were not uniform in patients with dilated cardiomyopathy or in those with acute myocarditis, and that angioscopy can be used as a guiding tool for endomyocardial biopsy.

Acute Disease↗
PubMed1990

PT pretreatment inhibits 48/80-induced activation of Ca(+)-permeable channels in rat peritoneal mast cells.

We recently reported that the secretagogue, compound 48/80, activated Ca2(+)-permeable channels of mast cells possibly via a second messenger [Kuno, Okada, and Shibata. Am. J. Physiol. 256 (Cell Physiol. 25): C560-C568, 1989]. The effects of pretreatment with pertussis toxin (PT) on compound 48/80 (48/80)-induced activation of the Ca2(+)-permeable channel have now been investigated by measuring Ca2+ signals of cell suspensions using the Ca2+ indicator fura-2 and by recording Ba2+ currents through the channel using the patch-clamp technique. In the presence of extracellular Ca2+, the fluorescence change was biphasic, with an immediate rise and a delayed peak at room temperature. The delayed peak, mainly due to Ca2+ entry through plasma membranes, was greatly reduced by pretreatment with PT. The quenching of the fluorescence by 48/80-induced Mn2+ influx was also decreased by PT, whereas the Ca2+ transients due to Ca2+ release from the intracellular stores apparently did not change. In patch-clamp recordings from cell-attached patches with pipettes containing isotonic Ba2+, the 48/80-induced Ba2+ currents were either suppressed or delayed in the PT-treated cells, under conditions where degranulation was absent. These results suggest that PT-sensitive GTP-binding protein is involved in activating the Ca2(+)-permeable channel in mast cells during stimulus-secretion coupling.

Animals↗
PubMed1990

[Angiographic studies on the effects of a novel calcium antagonist AE0047 on cerebral arteries in dogs, with special reference to the preventive effects of AE0047 on cerebral vasoconstriction induced by endothelin].

AE0047, a novel calcium antagonist, has mild and long-acting hypotensive effects. This drug also has more selective dilating action on cerebral arteries than on other systemic ones. We studied the cerebral vasodilatative effects of AE0047 by means of vertebral angiography in anesthetized dogs. Vertebral blood flow (VBF) was significantly increased by 91, 139 and 132% in 10, 30 and 60 min after intravenous administration of AE0047 at 30 micrograms/kg, respectively. No difference in vasodilating action was observed among basilar, posterior communicating, middle cerebral and internal carotid arteries. In basilar artery, the dilatative rate was about 30% between 10 and 60 min after injection of AE0047. Following intravertebral administration of endothelin at 100 pmol/kg, small vessels of the cerebral artery were constricted, and VBF was gradually decreased. AE0047 eliminated the vasoconstriction and increased VBF. Moreover, the vasoconstrictive effect of endothelin was prevented by pre-treatment of AE0047. These results indicate that AE0047 has potent vasodilating and spasmolytic actions on cerebral arteries.

Animals↗
PubMed1990

Effect of aspirin on the pressor activity of endothelin.

To examine the inhibition of prostaglandins to the pressor activity of endothelin, hemodynamic changes of dogs pretreated with aspirin in response to endothelin were compared with those of control. In control dogs, endothelin rose blood pressure due to vasoconstriction, with a transient vasodilation in some dogs in the initial phase. In dogs treated with aspirin, the initial vasodilation and the subsequent vasoconstriction were also noted, but the zenith of the total peripheral resistance was observed earlier, compared with control dogs. Thus, prostaglandins do not appear to have a role in the initial vasodilatory action of endothelin, but may modify the long lasting vasoconstriction in the late phase.

Animals↗
PubMed1989

Human diabetes associated with a deletion of the tyrosine kinase domain of the insulin receptor.

The insulin receptor has an intrinsic tyrosine kinase activity that is essential for signal transduction. A mutant insulin receptor gene lacking almost the entire kinase domain has been identified in an individual with type A insulin resistance and acanthosis nigricans. Insulin binding to the erythrocytes or cultured fibroblasts from this individual was normal. However receptor autophosphorylation and tyrosine kinase activity toward an exogenous substrate were reduced in partially purified insulin receptors from the proband's lymphocytes that had been transformed by Epstein-Barr virus. The insulin resistance associated with this mutated gene was inherited by the proband from her mother as an apparently autosomal dominant trait. Thus a deletion in one allele of the insulin receptor gene may be at least partly responsible for some instances of insulin-resistant diabetes.

Adolescent↗
PubMed1989

Effect of nicorandil on coronary spasm.

In patients in whom dynamic coronary obstruction plays a predominant role in the pathogenesis of angina pectoris, dilatation of large coronary arteries and relief of coronary spasm account for the main mechanism of action of antianginal drugs. In this study, the acute vasodilating effects of nicorandil, a newly developed antianginal drug, were assessed in 10 patients who had spontaneous and ergonovine-evoked coronary spasms. The prompt, complete relief of both spontaneous and evoked coronary spasms was obtained in all of 10 patients with nicorandil. The coronary spasmolytic effect of nicorandil in the present series is thus considered to be beneficial to the treatment of coronary spasm.

Adult↗
PubMed1989

Angina preceding myocardial infarction and residual coronary narrowing after intracoronary thrombolysis.

Thirty-six consecutive patients with evolving acute myocardial infarction underwent emergent coronary angiography and intracoronary thrombolysis with urokinase. Nineteen of the patients had had angina before the infarction (group A), whereas the infarction was unheralded in the remaining 17 (group B). Thirty-two vessels (88%) were patent at follow-up angiography performed after 3 to 4 weeks, and the residual stenosis was 87% +/- 14% in group A and 47% +/- 25% in group B (p less than 0.001). Coronary spasm was provoked by ergonovine maleate in four of 12 patients in group A (33%) and in three patients in group B (18%). Coronary revascularization was undertaken in nine patients in group A and three in group B. These results indicate that patients with angina preceding acute myocardial infarction are more likely to have significant stenosis even at the late follow-up stage and to have a more urgent need for subsequent coronary revascularization. It also seems apparent that thromboembolism in most patients and coronary spasm in a few patients without significant coronary narrowing play significant causal roles in the onset of acute myocardial infarction.

Adult↗
PubMed1989

Enhancement of arterial thrombolysis with native tissue type plasminogen activator by pretreatment with heparin or batroxobin: an angioscopic study.

The enhancement of canine arterial thrombolysis with native tissue type plasminogen activator (nt-PA) obtained from human-derived normal cells by pretreatment with heparin or the defibrinogenating agent, batroxobin, was evaluated with angioscopy. The nt-PA, 0.25 mg/kg, was infused intravenously to lyse 1-hour-old thrombus (eight thrombosed arteries without medication, seven with nt-PA alone, seven with nt-PA and heparin, and seven with nt-PA plus batroxobin). Angioscopy provided a cross-sectional view of the vessel lumen with clear visualization of the thrombus. Thirty minutes after nt-PA infusion, the percent luminal obstruction decreased from 74 to 61 in nt-PA alone (p less than .025), from 77 to 37 in nt-PA plus heparin (p less than .005), and from 79 to 25 in nt-PA plus batroxobin (p less than .005). Fifteen minutes after drug infusion, plasma fibrinogen levels decreased to 89% of preinfusion value in nt-PA alone, to 84% in nt-PA plus heparin, and to less than 5% in nt-PA plus batroxobin. Thus rapid infusion of nt-PA alone provided slight thrombolytic effects. However, heparin and batroxobin showed marked enhancement of thrombolytic effects of nt-PA.

Angiography↗
PubMed1989

Type IIa hyperlipoproteinemia masquerading as cerebrotendinous xanthomatosis.

We describe an adult patient with type IIa hyperlipoproteinemia, presenting with Achilles tendon xanthomas, cataracts, dementia, ataxia, pyramidal tract signs, and peripheral neuropathy, which are commonly seen in cerebrotendinous xanthomatosis (CTX). However, the diagnosis of CTX was excluded on the basis of the cholestanol level and the normal cholestanol/cholesterol ratio in his serum and tendon. The pathomechanism for some of the clinical manifestations in type IIa hyperlipoproteinemia and CTX might be caused by a common biochemical disturbance.

Aged↗
PubMed1989

Epidemiological study on periodontal diseases and some other dental disorders in dogs.

The prevalence of dental disorders in dogs was studied by applying index systems for human with some modifications. A total of 251 mongrel dogs including 143 stray dogs kept in the Animal Protection Offices in Tokyo and Hokkaido and 108 pet dogs visiting veterinary clinicians in Chiba Prefecture and Hokkaido were used. Periodontitis was prevalent among these dogs regardless of their sources and its incidence was increased with age. The lesion was more severe and more frequent in the premolar and molar regions than in the maxillary and mandibular incisor regions. Missing of teeth was observed at a high and increasing incidence with age. The tooth most commonly lost was the first premolar, followed by the other premolars and molars, where severe periodontitis was frequently found. Calculus was seen on many teeth, and aging agravated its prevalence and severity. Dental caries was observed in stray dogs, but neither to a serious degree nor at a significant level. These findings emphasize the necessity of dental hygiene, proper dental care and continuous periodical survey for dogs.

Age Factors↗
PubMed1989

Familial type C syndrome of insulin resistance and short stature with possible autosomal dominant transmission.

We describe a 17-yr-old girl with insulin resistant diabetes, acanthosis nigricans, hirsutism and short stature. At the age of 14 she was found to have glycosuria and diagnosed as diabetes mellitus. No endocrinological abnormality except transient amenorrhea and exaggerated LH response to LHRH was found. Insulin resistance was demonstrated by fasting hyperinsulinemia, insulin tolerance test and euglycemic glucose clamp test, and large doses of insulin with CSII were not effective in controlling blood glucose. Insulin binding to erythrocytes was normal, suggesting a postbinding defect. The same phenotype of insulin resistant diabetes and short stature was found in her mother who was diagnosed as diabetes mellitus at the age of 31 and died of diabetic nephropathy at the age of 41. Her maternal grandfather and uncle were reportedly affected with the same phenotype. Her father had impaired glucose tolerance, but no hyperinsulinemia. Two sisters had essentially normal glucose tolerance. Insulin binding to erythrocytes of her father and mother was also in the normal range. These results suggest that the present case may be a rare syndrome present together with type C syndrome of insulin resistance, and with short stature which was inherited autosomal dominantly.

Acanthosis Nigricans↗
PubMed1989

[Effects of mechanical stress on cytotoxicity of cobalt-chromium alloys for denture base].

The effects of metal ions and mechanical stress on cells were examined in vitro, to shed light on tissue response to metal prosthesis. Seven commercial base alloy plates, four Co-Cr alloys, one pure Ti, one Ni-Cu-Ga alloy and one Ni-Cr alloy for solder were used. Two kinds of static load, 5 gf/cm2 and 10 gf/cm2, were applied to three kinds of tissue culture cells, L-929, HEp-2 and Gin-1 cells, for 24 hours, and then the cells were incubated for 7 days under normal culture conditions. Cell recovery was evaluated by cell number and protein content. The amount of dissolved metal ions was measured by atomic absorption spectroscopy (Experiment 1). A concomitant study of cell culture with known amounts of Co, Cr, Ni was carried out, and cell recovery was examined (Experiment 2). Atomic absorption spectroscopy showed that dissolution of either Co or Cr from the alloys tested was extremely small. However, the maximum amount of Ni and Cu dissolved from Ni-Cu-Ga alloy and Ni-Cr alloy for solder was over 10 ppm. Ti was not dissolved from pure Ti. Four Co-Cr alloys and pure Ti did not inhibit cell recovery or protein content with loading. However, Ni-Cu-Ga alloy and Ni-Cr alloy significantly inhibited cell recovery and protein content, and the effects were enhanced by loading. The cytotoxicity of Co, Cr or Ni ion at a static load of 10 gf/cm2 was higher than that at 5 gf/cm2. These results suggest that mechanical stress increases the cytotoxicity of dissolved metal ions.

Cells, Cultured↗