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Biomedical subjects

J Yano

Publications and source records attributed to J Yano.

At least 91 records · Page 5Linked to original sources
PubMed1986

Enhancement of thrombolysis with tissue-type plasminogen activator by pretreatment with heparin.

The effect of pretreatment with heparin on lysis of arterial thrombi by tissue-type plasminogen activator (rt-PA) was studied in 19 dogs. Copper coil-induced carotid artery thrombi were weighed, inserted into the femoral arteries, and exposed to a 15 min infusion of rt-PA at 10 micrograms/kg/min either with (n = 6 thrombi) or without pretreatment with a 200 unit/kg bolus of heparin (n = 6 thrombi). The infusion of rt-PA without pretreatment reduced the thrombus weight by 27.6 +/- 7.4%, while infusion of rt-PA with pretreatment reduced it by 79.1 +/- 12.3% (p less than .0001). To test the hypothesis that heparin enhanced thrombolysis by preventing continued incorporation of new fibrin into the thrombus during thrombolysis we repeated the experiments using pretreatment with 8 U/kg of ancrod, which rapidly depletes fibrinogen. Pretreatment with ancrod (n = 6 thrombi) depleted fibrinogen and enhanced the lytic effect of rt-PA to a similar degree as pretreatment with heparin, resulting in a 67.6 +/- 12.3% (NS) decrease in thrombus weight. We conclude that heparin significantly enhances the thrombolytic effect of rt-PA, probably by preventing new fibrin formation and its incorporation into the thrombus during lysis.

Ancrod↗
PubMed1986

Inhibition of sperm penetration through human zona pellucida by antisperm antibodies.

An in vitro penetration test using human spermatozoa, sera, and eggs stored in a highly concentrated salt solution was designed for examination of the effect of antisperm antibodies on the process of fertilization. Spermatozoa from a healthy fertile donor incubated in modified Biggers, Whiiten and Whittingham (BWW) medium containing 7.5% antisperm-antibody-negative serum, could penetrate through the zonae pellucidae of the stored eggs, but not when the spermatozoa from the same donor had been incubated in modified BWW medium containing 7.5% antisperm-antibody-positive serum. After the antisperm-antibody-positive serum was absorbed with washed spermatozoa, the sperm penetration was not blocked. Therefore, antisperm antibodies appear to block human sperm penetration through the human zona pellucida.

Adult↗
PubMed1986

[Local irritation study with isepamicin].

Local irritative effects of isepamicin (HAPA-B) were studied using muscle and blood vessel of Japanese White rabbits. Muscle irritation experiment was carried out with a single dosage of 100 mg HAPA-B, 100 mg amikacin (AMK), saline, 0.75% acetic acid or 6.0% acetic acid administered into musculus sacrospinalis. Vascular irritation experiment was carried out by allowing HAPA-B to remain in a sealed section of vena retroauricularis for 3 minutes after injection. In result, the muscular irritative activity of HAPA-B was less severe than 0.75% acetic acid but more than saline, and almost equal activity to AMK was observed. The HAPA-B caused very slight inflammation while thrombus was not formed. The vascular irritative activity was very little.

Animals↗
PubMed1985

Induction of follicular growth in the squirrel monkey (Saimiri sciureus) with human urinary follicle-stimulating hormone (Metrodin).

Human urinary follicle-stimulating hormone (Metrodin, Serono Laboratories, Inc., Randolph, MA), an investigational drug which is purified from human menopausal gonadotropin (hMG) (Pergonal, Serono Laboratories, Inc.), was tested for its effects on induction of follicle development in the squirrel monkey (Saimiri sciureus). Metrodin was as effective as hMG for induction of follicle development in the squirrel monkey, and it appeared to be superior to hMG or porcine follicle-stimulating hormone at lower dose rates. The percentage of cornified cells in vaginal smears increased during stimulation and showed a parallelism with estrogen levels in serum and with follicular development. The results of the recovery rate of matured ova in different regimens show that use of Metrodin is a most convenient method for induction of follicle development and ovum recovery in the squirrel monkey.

Animals↗
PubMed1985

supN ochre suppressor gene in Escherichia coli codes for tRNALys.

We describe the cloning and nucleotide sequence of a new tRNALys gene, lysV, in Escherichia coli. An ochre suppressor allele of this gene, supN, codes for a tRNALys with anticodon UUA, presumably derived by a single base change from a wild-type UUU anticodon. The sequence of the supN tRNALys is identical to the sequence of ochre suppressor tRNAs encoded by mutant alleles at the lysT locus. This locus, which contains the two previously known tRNALys genes of E. coli, is located far from the lysV locus on the chromosome.

Anticodon↗
PubMed1984

Effects of late coronary artery reperfusion after myocardial necrosis is complete.

Early reperfusion salvages reversibly injured ischemic myocardium. Late reperfusion, after necrosis is complete, could be beneficial by accelerating healing, or the hemorrhage and contraction-band necrosis associated with reperfusion could impair healing. In closed-chest anesthetized dogs the left anterior descending coronary artery was occluded with a balloon-tipped catheter for either 1 day followed by reperfusion for 6 days (n = 9) or for 7 days without reperfusion (n = 9). All dogs were killed after 7 days. Pathologic changes were studied in transverse whole-mount ventricular histologic sections. When the two groups were compared, no differences were found in: (1) infarct size, 15.7 +/- 9.9% vs 10.2 +/- 8.6 (mean +/- SD); (2) number of transmural infarcts, 5 of 9 vs 6 of 9; (3) ratio of infarcted/normal wall thickness, 0.93 +/- 0.09 vs 0.95 +/- 0.13; (4) thickness of zone of collagen deposition at periphery of infarct, 1.69 +/- 1.16 mm vs 1.67 +/- 0.56; and (5) amount of hemorrhage, calcification, and inflammation. Thus, in this model, reperfusion after necrosis is complete did not improve or impair healing.

Animals↗
PubMed1983

[Increase in pulmonary resistance induced by Forssman antiserum in guinea pigs].

Intravenous injection of Forssman antiserum produced a diphasic increase in pulmonary resistance in guinea pigs. The first increase (phase I) occurred with 20 sec latency after injection of Forssman antiserum. The second increase (phase II) occurred immediately thereafter, and this lasted more than 30 min and was irreversible. In the lung, hemorrhages and edema were evident. Hemorrhagic fluid was noted in the bronchiole and the alveoli. Polymorphonuclear leucocytes aggregated in the capillary lumen. The endothelial lining of the venule had been destroyed. Phases I and II were not blocked by DSCG. These were completely blocked by cobra venom factor and carrageenin. Isoproterenol, salbutamol and aminophylline selectively blocked phase I. Also, aminophylline weakly blocked phase II. Cyproheptadine blocked phase I, but chlorpheniramine did not. In contrast, indomethacin and aspirin selectively blocked phase II. Superoxide dismutase significantly blocked phase II, but inactivated superoxide dismutase and catalase did not. The present findings suggest that activation of the complement system appears to be essential for the induction of the increase in pulmonary resistance mediated by Forssman antiserum. Phase I is probably due to the contraction of the respiratory tract. Serotonin may be one of the substances for this contraction. In contrast, phase II is due to disintegration of the endothelial lining and extravasation of hemorrhagic exudates into the respiratory tract. Prostaglandins and/or superoxide radical may take part in the phase II response.

Airway Resistance↗
PubMed1983

Neutrophil disorders in a child with necrotizing external otitis.

A two year old child presented with a history of cyclic fever since the sixth week of life, and otorrhea of six weeks' duration, unresponsive to treatment. Surgical removal of massive granulation tissue and sequestrated bone, combined with parenteral administration of pipellacillin and dibekacin successfully resolved the Pseudomonas infection. Neutropenia and the decreased chemotactic activity of neutrophils were observed in this patient. This neutrophil disorder seemed to be primary and a contributing factor.

Agranulocytosis↗
PubMed1982

Dependence of membrane potential on Ca2+ transport in cultured cytotrophoblasts of human immature placentas.

The electrical membrane properties of cultured human cytotrophoblast were examined by means of a standard electrophysiological technique. The mean values of the membrane potential (Rm) and the membrane resistance in a physiological medium were around -49 mV and 12 M omega , respectively. The membrane potential was dependent, to a large extent, on the external Ca2+ concentration ([Ca2+]o). Deprivation of external Ca2+ reduced membrane potential to about -20 mV, and an increase in [Ca2+]o caused a hyperpolarization in a saturable manner. The Ca2+-dependency of membrane potential was affected remarkably by [K+]o, but not by [Na+]o or [Cl-]o. The intracellular Ca2+ injection hyperpolarized the membrane in a Ca2+-free medium. A Ca2+ channel blocker, verapamil, completely abolished the Ca2+-dependent Em. The Ca2+-dependent Em was also suppressed by cooling or by the application of metabolic inhibitors. It is suggested that the Ca2+-dependent Em in cultured human cytotrophoblast is caused by a Ca2+ influx which, in turn, increases the K+ conductance of the cell membrane, presumable due to stimulation of Ca2+-activated K+ channel.

Biological Transport, Active↗
PubMed1982

Chronic myringitis and chronic suppurative otitis media.

Thirty-four chronic myringitis cases were examined by otoscopy, pure tone audiometry, tympanometry, skull X-rays, and bacteriologic study of otorrhea. Five atypical cases are presented in detail. Three of these five cases had a perforation of the tympanic membrane preceding the appearance of typical chronic myringitis. The remaining two cases showed a transient small tympanic membrane perforation during the long course of chronic myringitis. These cases suggest that chronic myringitis could occur in some chronic suppurative otitis media and that myringitis could cause tympanic membrane perforation.

Adult↗
PubMed1982

Personality factors in pathogenesis of polyps and nodules of vocal cords.

Patients who were diagnosed as polyps or nodules of vocal cords (PN group), and two control groups were tested with Japanese version of Maudsley Personality Inventory to evaluate the personality characteristics of patients with these behavior-induced vocal cord diseases. PN group showed significantly higher E (extraversion-introversion) scores than each control group. This extraversive tendency had no relation to their age, sex, polyp or nodule, and occupation. N (neuroticism) scores were not significantly different between PN group, and each control group. L (lying) scores of PN group were significantly lower than a control group. It was suggested that extraversive personality was one of the important factors relating to the pathogenesis of vocal cord polyp and nodule.

Adult↗
PubMed1982

Intermittent brief periods of ischemia have a cumulative effect and may cause myocardial necrosis.

We investigated the effects of brief intermittent periods of ischemia on myocardial viability. Brief periodic coronary occlusions were produced up to 18 times by inflating and deflating the balloon of an intracoronary No. 2F catheter for periods of 15, 10 or 5 minutes, followed by 15-minute periods of reperfusion. Creatine kinase (CK) release, triphenyl tetrazolium chloride staining, and light and electron microscopy were used to detect the presence of myocardial necrosis. For the study of CK release, blood was taken from the great cardiac vein and the aorta before and at 5-minute intervals during each left anterior descending coronary occlusion, as well as during and 1, 5, 10 and 15 minutes after balloon deflation. In seven of 24 dogs with 15-minute occlusions, in five of 21 dogs with 10-minute occlusions, and in three of 32 dogs with 5-minute occlusions, small but distinct areas of subendocardial necrosis were present. In all dogs with morphologic proof of necrosis, there was periodic release of CK into the great cardiac vein, which peaked immediately after reperfusion, reflecting CK washout. Thus, brief periods of ischemia, which when single do not cause necrosis, have a cumulative effect and may cause myocardial necrosis. This mechanism of necrosis may be relevant clinically in patients with frequent anginal episodes. Since many dogs of this study did not have any myocardial necrosis, the findings also suggest that intermittent reperfusion has a beneficial effect and may prevent necrosis, even when total occlusion time exceeds 200 minutes.

Animals↗