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Biomedical subjects

H Horikawa

Publications and source records attributed to H Horikawa.

At least 37 records · Page 2Linked to original sources
PubMed1996

Effect of S-ethylisothiourea, a putative inhibitor of inducible nitric oxide synthase, on mouse skin vascular permeability.

By dye leakage in mouse skin, we evaluated the inhibition of proinflammatory stimuli-induced plasma extravasation by a putative inhibitor of inducible nitric oxide synthase, S-ethylisothiourea. A low dose of S-ethylisothiourea (5 micrograms/kg) mimicked aminoguanidine in inhibiting the plasma extravasation elicited by lipopolysaccharide but not by 5-hydroxytryptamine or platelet-activating factor. A higher dose of S-ethylisothiourea (10 micrograms/kg) inhibited the plasma extravasation induced by 5-hydroxytryptamine slightly; however, it increased the basal dye leakage. Thus, S-ethylisothiourea may be used as a relatively specific inhibitor for inducible nitric oxide synthase in vivo.

Animals↗
PubMed1996

Initial transient phase of salivary secretion by the submandibular glands of rats under anoxic conditions.

Salivary secretion of the rat submandibular gland exhibits two phases upon administration of acetylcholine (ACh, 10(-6) M): an immediate initial transient phase of rapid secretion lasting 5 min followed by a longer steady phase of slower secretion. Application of an anoxic perfusate bubbled with 100% N2 for 10-20 min had no effect on the initial phase of secretion, but caused a marked decrease in secretion in the steady phase following stimulation with 10(-6) M ACh. After secretion under the anoxic condition, a recovery period without stimulation was performed for 30 min by perfusion with HEPES Ringer's solution bubbled with 100% O2 and containing various potassium concentrations. The initial secretion rate measured with application of an anoxic perfusate was markedly increased by the high-K+ recovery perfusate (25 mM) and decreased by the K(+)-free recovery perfusate. Administration of 10(-3) M ouabain in the normal perfusate resulted in inhibition of secretion during the steady phase similar to that seen under the anoxic condition, while the secretory rate during the initial phase remained unchanged. We concluded that the initial phase of secretion is relatively resistant to anoxia, and that oxygen supply and Na(+)-K+ pump activity were essential for maintaining the steady phase of secretion.

Acetylcholine↗
PubMed1996

[A fundamental study of relationships between rhinomanometry and acoustic rhinometry].

A cylindrical model consisting of a single or plural acrylic plates with holes of various cross-sectional areas was ventilated by a Harvard pump. Pressure flow curves of the combinations were drawn and analyzed according to the percent expression method. The length of the cylinder through the same cross-sectional area did not influence the ventilatory resistance. Divergent flow toward the downstream part decreased the resistance, but convergent flow from the upstream part did not. Simultaneous setting of convergent flow from the upstream part and divergent flow to the downstream part decreased the resistance most effectively, as much as approximately 70% of the original resistance. Two separately positioned cross-sectional areas in a respiratory circuit increased the resistance about 1.4 times when the separation length was more than 3 cm, while the resistance remained between 1 and 1.4 times when the separation was shorter than 3 cm. The average values of the minimum areas measured by acoustic rhinometry were usually much larger than expected from the present study. One of the factors affecting this difference may be that the axis from the nostril to the choana is complicated enough to significantly modify the aerodynamics of the nasal cavity.

Acoustics↗
PubMed1996

[A sporadic case of dentatorubral-pallidoluysian atrophy (DRPLA) having an elderly age of onset].

We reported a sporadic case of DRPLA that had an elderly age of onset. The patient was a 71-year-old woman. Her parents, sisters and a brother didn't have neurologic diseases. She had been well until the age of 68 years, when she noticed her unstable gait. On neurologic examination cerebellar ataxia and a tremor at the neck were noticed, but we were unable to differentiate her disease from the other types of spinocerebellar degeneration. An MRI of the cranium showed atrophy of the cerebellum, pons, brain stem and cerebrum, and a diffuse lesion of the cerebral white matter. These findings made us suspect her disease of DRPLA. When we analyzed the CAG repeat in the DRPLA gene, we found it expanded to 57. We thought that the elderly onset related to a relatively mild expansion.

Age of Onset↗
PubMed1996

The relationship between trinucleotide repeat length and phenotypic variation in Machado-Joseph disease.

Trinucleotide repeat expansion in the Machado-Joseph disease (MJD) gene has been found in 26 patients from 20 unrelated Japanese families. Expanded alleles had 68 to 84 repeats, whereas normal alleles had 14 to 37 repeats. The age of onset was inversely correlated with the repeat length. To evaluate in detail the relationship between the repeat length and clinical features, we subdivided the 26 patients into three groups on the basis of the repeat length (group 1, 78 repeats or more; group 2, 74 to 77 repeats; group 3, 73 repeats or less). Group 1 and group 2 had common features of spasticity, hyperreflexia, Babinski sign, bulging eyes, facial myokymia and extrapyramidal signs as well as cerebellar ataxia and ophthalmoplegia. It should be noted that group 1 showed more prominent pyramidal and extrapyramidal signs than group 2. In contrast, group 3 showed hypotonia, hyporeflexia and sensory disturbance in addition to cerebellar ataxia and ophthalmoplegia. These findings suggest that the repeat length plays an important role in phenotypic variation. DNA analysis for the MJD mutation was clearly useful for making an accurate diagnosis in patients without bulging eyes, facial myokymia, dystonia or marked spasticity.

Adult↗
PubMed1994

The role of gravity in chick embryogenesis.

Thirty fertilized chick eggs preincubated for 0, 7 and 10 days on earth (10 eggs each) were flown in the space shuttle 'Endeavour' and further incubated for 7 days under microgravity. Twenty out of thirty eggs (9/10 ten-day-old; 10/10 seven-day-old; 1/10 zero-day-old) were recovered alive after landing. The only living embryo of the zero-day-old group died 24 days after launch, and was comparable to a 16-day-old embryo. The high mortality of the 0-day-old eggs appeared to be related to the specific inner structure of the egg. Simulation experiments performed on earth indicated that when yolk stayed in the albumen for more than 2 days, most of the embryos died. The subtle difference in specific gravity between the yolk (1.029) and albumen (1.040) plays a critical role in early chick embryogenesis.

Animals↗
PubMed1993

Effects of halothane and isoflurane anesthesia on sympathetic adrenal nerve responses to carbon dioxide challenge in rats.

We studied the influence of two volatile anesthetics, halothane and isoflurane, on the circulatory and sympathetic nerve responses to carbon dioxide (9% CO2) in rats. Systolic blood pressure was depressed throughout the CO2 challenge and after an initial reduction, a gradual increase was observed in heart rate. Sympathetic adrenal nerve action potentials (SANA) significantly increased in contrast to negative responses in the circulatory functions. SANA responses against time were trapezoid in shape. There were no significant differences in SANA responses between 1% (1 MAC) and 1.5% (1.5 MAC) halothane groups, nor between 1.4% (1 MAC) and 2% (1.5 MAC) isoflurane groups. Halothane and isoflurane, therefore, did not produce dose-dependent effects on sympathetic response to hypercapnia within these concentrations. The maximum changes in SANA from the baseline values were 110% and 40% for the halothane and isoflurane groups, respectively. The sympathetic reflex response to hyperacapnia was retained at 1.5 MAC for both anesthetics, though isoflurane depressed these responses more markedly than halothane. Our results suggest that halothane is a more preferable anesthetic than isoflurane when viewed from the standpoint of preservation of sympathetic nerve response in such undesirable situations as severe hypercapnia occurring during anesthesia.

Journal Article↗
PubMed1992

The hemostatic effect of deacetylated chitin membrane on peritoneal injury in rabbit model.

In this study, we determined the effect of 80% deacetylated chitin (DAC-80) membrane on postsurgical bleeding after visceral and parietal peritoneal abrasion. Japanese white rabbits underwent a midline laparotomy followed either by a bilateral peritoneal sidewall abrasion (4 x 4 cm) or an abrasion of liver surface (3 x 2 cm). The injured surface was then covered with a 0.2 mm thick DAC-80 membrane. On postsurgical day 2, the rabbits were sacrificed and the amounts of postsurgical bleeding was determined by quantitating the number of red blood cells recovered in 50 ml peritoneal lavage fluid. The DAC-80 membrane was found to reduce postsurgical bleeding after the abrasion of liver surface (treated with DAC-80 membrane: 2.9 +/- 0.8; control: 24.6 +/- 5.9 x 10(8) cells/peritoneal cavity, P less than 0.005). This same hemostatic activity was not observed after application in the peritoneal sidewall abrasion model. We also measured plasminogen activator activity (PA) and urokinase inhibitory (PAI) activity in the spent culture media of macrophages recovered from the postsurgical peritoneal exudate. The DAC-80 membrane reduced the PA secretion from postsurgical macrophages after liver surface abrasion (treated with DAC-80: 2.8 +/- 0.7; control: 3.9 +/- 0.9 mPU/ml). The DAC-80 membrane also showed similar effects on PA secretion after peritoneal sidewall abrasion. No significant effects were found in the secretion of PAI by postsurgical macrophages in both surgical models. These findings suggest that the DAC-80 membrane may have hemostatic activity through the modulation of fibrinolytic activity of peritoneal exudative macrophages.

Adolescent↗
PubMed1992

A clinical study of postoperative infections following open-heart surgery: occurrence and microbiological findings in 782 cases.

A total 782 consecutive patients underwent open-heart surgery with CPB between January, 1979 and December, 1988, at the Yamagata University Hospital. We assessed the incidence of postoperative infections in relation to age, the duration of surgery and antibiotic prophylaxis, and examined the causative organisms, after which the types of infecting flora were compared between the 1st period, from 1979 to 1983 and the 2nd period, from 1984 to 1988. Postoperative infection occurred in 104 of the 782 patients (13.3 per cent); in the form of a wound infection in 41 (5.2 per cent), pneumonia in 33 (4.2 per cent), urinary tract infection in 9 (1.2 per cent), prosthetic valve endocarditis in 6 (0.8 per cent), and other infections in 15 (1.9 per cent). Patients aged under 12 months or over 60 years showed a higher incidence of infection, being 17.4 per cent and 19.2 per cent, respectively. Patients who underwent an operation of over 8 hours duration also had a significantly higher incidence compared to those whose operation time was less than 4 hours, being 32.9 per cent and 6.3 per cent, respectively (p less than 0.0001). There was no significant difference in the incidence of postoperative infection between patients given or not given preoperative prophylaxis. A total 123 species of organisms were isolated from the 104 patients, 52.8 per cent being gram-negative bacteria (GNB), and 43.9 per cent gram-positive bacteria (GPB), and a remarkable increase in the incidence of GPB was seen in the 2nd period compared to the 1st period from 31.7 per cent to 50.0 per cent.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

The effects of feeding on the development of metabolic acidosis in the rat: comparison between perfused liver in situ and whole animal.

Rat liver perfused in situ was charged with two concentrations of halothane. Lactate increased in a time- and dose-dependent manner in the liver of the fed rat, whereas its increase in the starved rat was much milder (1.7 --> 9.2 mmol. l(-1) vs 0.6 --> 1.4 mmol. l(-1) after a 3 hr charge with 6.0% halothane). Base excess decreased also more markedly in the fed rat. Glucose increased 2.3 times the control value in the fed rat, whereas it did not change significantly in the starved rat. Changes produced by enflurane were very similar to those produced by halothane. It was inferred that in the presence of halothane and enflurane, hepatic glycogen was transformed into glucose and then to lactate by the inhibition of NADH dehydrogenase. In the liver of the starved rat, glucose, hence lactate, did not increase because of the depletion of glycogen. When halothane (1.9%) was given to the whole animal, changes in lactate, base excess and glucose in the arterial blood were very mild. Marked disparities in these parameters between the two experimental models were inferred to be due to: 1) possible insinuation of anaerobic metabolism in the perfusion experiments, 2) a well-kept balance between the suppression of cellular metabolic activity and inhibition of energy production by halothane in the whole animal, and 3) involvement of neural and humoral factors in the intact whole animal.

Journal Article↗
PubMed1992

Syntheses and antiulcer activities of 2-aminonorbornene derivatives.

2,2,-Disubstituted norbornenes (1, 2), 2,2-Disubstituted norbornane (3), 2,2,3-trisubstituted norbornenes (4, 5), oxanorbornenes (6) and azanorbornenes (7) were synthesized by the Diels-Alder reaction using alpha, beta-dehydroamino acids as a key step, and their antiulcer activities were examined. The oxazolidine derivative (1h) exhibited the most potent activities against several ulcer-models in rat.

Animals↗
PubMed1992

[Diurnal sleep apnea in myotonic dystrophy].

We investigated diurnal sleep apnea in myotonic dystrophy with respiratory inductive plethysmography. Five of eight patients met criteria for sleep apnea syndrome and had central apnea mainly. In a case showing periodic breathing with apnea like Cheyne-Stokes type breathing, the duration of apnea and breath was even and the tidal volume went waxing and waning regularly. In the other four cases, central apneas were observed in sequence, but the duration of apnea and the tidal volume changed variously. Large breaths between apneas elevated arterial oxygen saturation rather than stable breaths without apnea. We suspected that hypoxemia, which exacerbated by involvement of respiratory muscles, supine position and sleep, initiated the hyperventilation between apneas. And then the saturation of oxygen raised by hyperventilation would cause central sleep apnea.

Adult↗
PubMed1992

[Aggravation of hypoxemia in supine position in myotonic dystrophy].

Myotonic dystrophy (MyD) involves a variety of systems. Respiratory disorders are common, namely elevation of diaphragm, alveolar hypoventilation, aspiration pneumonia and sleep apnea. We evaluated respiratory involvement. The subjects were 11 patients with MyD. Also 6 patients with limb girdle muscular dystrophy (LG) were examined to be compared with MyD. Both groups had the similar activities of daily living. All of them never complained of dyspnea. Arterial blood gas studies were performed in supine position and standing position. A new evidence was found that hypoxemia was aggravated and alveolar-arterial oxygen pressure difference was increased in supine position in MyD. Next, pulmonary function tests were done in supine position and sitting position. Functional residual capacity (FRC) were more reduced in supine position in MyD compared with LG. The value to subtract closing capacity from FRC was negative in supine position in MyD, showing closing phenomenon. We propose the mechanism of the aggravation of hypoxemia may be the following. The reduction of FRC caused by respiratory muscle involvement brings out the closing phenomenon. Abnormal uneven distribution of ventilation-perfusion ratio happens and then hypoxemia is worsened in supine position in MyD.

Adult↗
PubMed1992

[X-ray computed tomographic scans of lower limb and trunk muscles in facioscapulohumeral muscular dystrophy].

X-rays computed tomographic (CT) scans of muscles of the lower limbs and the trunk in 14 patients with facioscapulohumeral muscular dystrophy (FSH) were studied. The CT scans showed that the affected muscles were decreased in density and size. The laterality of muscular involvement was sometimes observed. The muscular lesions in the lower limbs showed proximal distribution. In the thigh, the hamstrings were affected first, the adductor muscles second, and then the muscular involvement progressed to the quadriceps femoris muscle. In the lower leg, the gastrocnemius and soleus muscles were relatively spared as compared with the tibialis anterior muscle. In the lumbar girdle, the abdominal muscles were involved first, the gluteal muscles second, the back muscles third, and the psoas major muscle were relatively spared. The muscular weakness of this distribution exacerbated lumbar lordosis. The neck muscles were less affected than those of the lumbar girdle. The CT scans in FSH demonstrated the characteristic pattern of muscular involvement, which differed from the inherited muscular diseases such as Duchenne muscular dystrophy, myotonic dystrophy, and others.

Adolescent↗
PubMed1991

[Pharmacokinetics of lidocaine in perfused rat liver].

Lidocaine pharmacokinetics were studied using perfused rat livers under several conditions. 1) In the low perfusion group (perfusion rate = 1/2 of control group), the elimination rate constant and clearance of lidocaine in the first phase were reduced, but in the second phase, metabolism of lidocaine was more active than in other groups. 2) High albumin concentration in the perfusate did not significantly affect lidocaine metabolism. 3) Low pH of the perfusate (pH = 7.10) did not affect the metabolism of lidocaine. 4) Acute and chronic liver damage inhibited the lidocaine metabolism, which may be due to decreases in viable hepatocytes, effective hepatic blood flow and mitochondrial P-450. 5) Halothane in the concentration of 2.5% reduced the lidocaine metabolism. This was probably due to inhibition of hepatocyte activity by halothane because increases in GOT, LDH and lactate in the perfusate and a decrease in the O2 consumption by the rat liver were observed.

Animals↗
PubMed1991

[A successful case of double outlet right ventricle accompanied with complete endocardial cushion defect].

Surgical correction of a case of double outlet right ventricle accompanied with complete endocardial cushion defect was completed successfully. No other complicated anomaly existed in this case. Correction was done by using two patch method. The patch for VSD was designed to be comma-like shape. For ensuring the left ventricular out tract, the patch was sutured with bulging at the circumference of the aortic orifice and the suture line of the patch with atrio-ventricular valve was deviated to the right. There was no stenosis in the left ventricular out tract and tricuspid valve.

Child, Preschool↗
PubMed1990

Growth hormone deficiency of hypothalamic origin in septo-optic dysplasia.

Hypothalamic pituitary function and growth hormone releasing hormone (GHRH) loading tests in two children with septo-optic dysplasia (SOD) revealed isolated GH deficiency in one and deficiencies of growth hormone, adrenocorticotropic hormone and antidiuretic hormone in the other. Secretion of GH was elicited in the first patient by single i.v. bolus administration of GHRH and after repetitive i.v. infusions of GHRH in the second. With these results we confirmed that the hypopituitarism in our patients with SOD was of hypothalamic origin. Both patients also had infantile spasms.

Adrenal Glands↗