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Biomedical subjects

M Katayama

Publications and source records attributed to M Katayama.

At least 217 records · Page 12Linked to original sources
PubMed1991

[Perspectives on chest wall mechanics in infants and young children].

The chest wall of neonates and infants is compliant and thus the outward recoil of the chest wall and the inward recoil of the lungs theoretically balance at a low lung volume (FRC) incompatible with gas exchange. The neonates and infants, however, have a number of mechanisms that actively maintain a high FRC: (1) Laryngeal breaking during expiration. (2) Short expiratory time relative to long time expiratory time constant. (3) Sustained inspiratory muscle tone during expiratory phase. When lung recoil is increased as in many disease states, the third mechanism fails due to muscle fatigue. The increased lung recoil pulls in the chest wall and a catastrophic decrease in FRC occurs. The measurement of respiration from the outside through chest wall movement is especially important in infants and young children for these reasons. The other reason is that the breathing pattern remains unaltered, unlike measurement via the airway such as by mask and pneumotachometer.

Biomechanical Phenomena↗
PubMed1990

The delayed adverse reactions of low osmolar contrast media.

A computer scale survey to inspect the occurrence of delayed symptoms (adverse reactions) associated with the intravenous injection of low osmolar contrast medium (LOCM) was carried out. Of the recovered 1070 questionnaires, 290 had the delayed symptoms. Excluding 59 patients having the same symptoms in the past one year without contact with the contrast medium, the overall incidence of the delayed adverse reaction is 22.8% (231/1011). The delayed symptoms include arm pain (6.0%), headache (3.6%), itching (2.3%), rash (1.5%), general fatigue (1.4%), gastrointestinal symptoms, etc. Though the chi-square test had shown significance of the occurrence of the delayed symptoms for the group with a past history of drug allergy and nasal allergy (p less than 0.05), the delayed symptoms were mainly distributed in the middle-aged female to indicate that the sexuality is the cause of the foresaid significance. Furthermore, the incidence of the objective delayed symptoms such as rash in the group who had accepted more than two examinations is lower than the incidence in the group who accepted only one examination in the survey period. The disagreement to the fact that the repeated usage of the contrast medium is the risk factor to increase the incidence of the adverse reactions indicates the contrast medium may not be the only cause for the occurrence of the delayed symptoms, e.g. other factors such as sexual and psychological factors etc. may play a more important role than the contrast medium under this type of survey.

Adolescent↗
PubMed1990

Partial purification and characterization of GDP dissociation stimulator (GDS) for the rho proteins from bovine brain cytosol.

A novel type of regulatory proteins for the rho proteins (rhoA p21 and rhoB p20), ras p21-like small GTP-binding proteins (G proteins), are partially purified from bovine brain cytosol. These regulatory proteins, named rho GDP dissociation stimulator (GDS) 1 and -2, stimulate the dissociation of GDP from rhoA p21 and rhoB p20. rho GDS1 and -2 are inactive for other ras p21/ras p21-like small G proteins including c-Ha-ras p21, smg p21B, and smg p25A. Since we have previously shown that the rate limiting step for the GDP/GTP exchange reaction of the rho proteins is the dissociation of GDP from these proteins, the present results suggest that rho GDS1 and -2 stimulate the GDP/GTP exchange reaction of the rho proteins. rho GDS1 and -2 are distinct from the GAP- and GDI-types of regulatory proteins for the rho proteins previously purified from bovine brain cytosol. rho GAP stimulates the GTPase activity of the rho proteins and rho GDI inhibits the GDP/GTP exchange reaction of the rho proteins. The present results together with these earlier observations indicate that the rho proteins are regulated by at least three different types of regulatory proteins, GDS, GDI, and GAP.

Animals↗
PubMed1990

Müllerian duct cyst: ultrasonographic and computed tomographic spectrum.

A Müllerian duct cyst (MDC) is the persistent remnant of the Müllerian duct. Reports of symptomatic cases are rare, signs and symptoms include perineal pain, dysuria, infertility, hematuria and genital inflammation. The prevalence of MDC has been previously reported as 4% of newborns and 1% in adult males. Herein we report six cases encountered in the past year. Our detection percentage was 1% and is compatible with the reported values. The imaging evaluation of symptomatic and asymptomatic patients with MDC is discussed as well as the apparent discrepancy between the number of previously reported cases and the reported prevalence.

Adolescent↗
PubMed1990

Control of expression of Agrobacterium vir genes by synergistic actions of phenolic signal molecules and monosaccharides.

Most virulence (vir) genes of Agrobacterium tumefaciens that are required for the formation of crown gall tumors are expressed in response to such plant signal molecules as acetosyringone and lignin precursors. The phenolic signals are transduced through a receptor VirA protein in the inner membrane of the bacterial cell. The expression of these genes triggers the transfer of a specific DNA segment, called transferred DNA (T-DNA), from the Ti plasmid to plant cells, and its integration into their nuclear DNA. We show here that a group of aldoses (L-arabinose, D-xylose, D-lyxose, D-glucose, D-mannose, D-idose, D-galactose, and D-talose) can markedly enhance acetosyringone-dependent expression of vir genes when the concentration of acetosyringone is limited (10 microM) but does not enhance the expression of noninducible genes. Likewise, a 2-deoxy-D-glucose, a nonmetabolized sugar, is also effective. When a deletion was introduced into the virA gene in the region encoding the periplasmic portion of the VirA protein, enhancement by glucose disappeared, but vir expression was induced by acetosyringone in this mutant. These results suggest that these sugars directly enhance a signaling process initiated by phenolic inducers that results in an increase in expression of the vir genes.

Journal Article↗
PubMed1990

Age-related changes in urinary growth hormone level and its clinical application.

In order to establish the normal range of urinary growth hormone (GH) level for age and sex, which is important in the clinical application of urinary GH to diagnosis, we measured GH in the first morning urine specimens of 270 normal subjects aged 3 to 20 years. Urinary GH levels in patients with documented GH deficiency were compared with those of the normal controls. In normal subjects, urinary GH levels showed a statistically significant change with age. They were relatively high in infancy and mid-puberty, reaching a peak at 11 to 12 years in girls and at 13 to 14 years in boys. Urinary GH levels in patients with complete GH deficiency were apparently lower (less than -2.0 SD) than those of the normal children, while the levels in patients with partial GH deficiency overlapped with the normal range. When assessing GH secretion by using urinary GH measurement, consideration of age and sex is required, since the level changes significantly with these factors.

Adolescent↗
PubMed1990

Analysis of breathing pattern in children with asthma.

The breathing pattern in children with asthma was studied, using respiratory inductive plethysmography. The subjects were 31 children with mild to moderate asthma (15 males, 16 females; aged 6-15 years, average 11 years). The respiratory rate was 25.5 +/- 10.7/min. (mean +/- S.D.) during asthma attacks and 18.4 +/- 5.0/min. between attacks with a significant increase during attacks (P less than 0.001). The expiratory time was 1.774 +/- 0.833 second during attacks, and 2.125 +/- 0.602 seconds between attacks. The expiratory time to total respiratory time ratio (TE/TTOT) was 0.631 +/- 0.056 during attacks and 0.608 +/- 0.035 between attacks. Thus there was a slight prolongation at the time of attack, but the difference was not significant. The tidal volume was increased slightly during mild and moderate attacks. VT/TI (mean inspiratory flow) was increased during attacks. The respiratory pattern was thoracic during attacks and changed to the abdominal pattern with improvement.

Adolescent↗
PubMed1990

[Products in the fluorometric reaction of purines with 4,5-dimethyl-o-phenylenediamine after oxidation using N-bromosuccinimide].

Twelve purines oxidized with 4,5-dimethyl-o-phenylenediamine (DMPD) was found to react with N-bromosuccinimide (NBS) to give fluorescent derivatives. In this paper, the identification of oxidation and fluorescent products have been described. In compliance with the substituent on purine skelton, three alloxans were obtained from twelve purines after oxidation by using NBS. The three alloxans reacted with DMPD to form two quinoxalines and an alloxazine, all of which being fluorescent.

Alloxan↗
PubMed1990

Signal-averaging electrocardiogram in patients with diabetes mellitus.

In order to detect silent impairment of the heart due to diabetes mellitus, the signal-averaging electrocardiograms (ECG) of 21 healthy subjects and 22 diabetic patients without ventricular tachycardia were compared. The QRS duration in the signal-averaging ECG was longer in diabetic patients than in the normal subjects (87.3 ms vs. 114.5 ms, p less than 0.01). Moreover, late potentials in the terminal portion of the QRS complex were observed in 7 diabetic patients (32%), but in only one normal subject (5%, p less than 0.01). These findings suggested that patients with diabetes mellitus frequently have intraventricular conduction disturbances, presumably due to diabetic microangiopathy.

Adult↗
PubMed1990

[Changes in the liver weight in the elderly].

To elucidate the effect of aging on liver weight in the elderly, 582 elderly cases (male 291, female 291), were selected from 2000 elderly autopsied cases on the basis of being free from pathological findings affecting liver weight. Both liver weight and its ratio to body weight decreased with age, and influenced by obesity; the former increased and the latter decreased in obese cases. Analysis according to the degree of obesity also showed decrease of liver weight and is ratio to body weight with age. Comparison between males and females of the same decade revealed the tendency that in females the liver weight was low, while liver weight.body weight ratio was high. The same results were obtained by analysis based on the degree of obesity.

Aged↗
PubMed1990

[Magnetocardiographic localization of an accessory pathway in patients with WPW syndrome].

The usefulness of magnetocardiography (MCG) in determining the location of an accessory pathway (Kent bundle) was examined by the isomagnetic map at the time of a delta wave, and by gated magnetic resonance imaging (MRI). MCG was performed at 36 points on the anterior chest wall in eight cases with Wolff-Parkinson-White (WPW) syndrome using a SQUID (superconducting quantum interference device) system with the second derivative gradiometer. Based on these records, isomagnetic maps during the QRS and T waves were constructed, and the depth of the accessory pathway from the coil was calculated mathematically. The locations of the accessory pathways were estimated using these data and the MRI findings. The locations of the accessory pathways thus determined were compared with findings obtained by body surface maps. A dipole directed towards the left was deduced, because the maximum was located more superiorly than the minimum in an isomagnetic map 10-40 msec after onset of the delta wave in cases with WPW syndrome, indicating an accessory pathway to be located in the right ventricle. A dipole directed towards the right was deduced, because the maximum was located more superiorly than the minimum in an isomagnetic map 10-40 msec after onset of the delta wave of cases with WPW syndrome indicating an accessory pathway to be located in the left ventricle. Assuming the electric current source is a single dipole, the location of a current dipole might be determined by positions of the maximum and the minimum in the isomagnetic maps. In the present study, the locations as determined by analysis of the isomagnetic map 40 msec after onset of the delta wave and the gated MRI were concordant with the findings obtained by body surface isopotential maps. Furthermore, some cases showed two opposing dipoles on the isomagnetic map at the peak of the T wave in lead II of the standard ECG leads; one directed to the left expressing normal repolarization; the other directed to the right presumably expressing repolarization of the myocardium which was excited by an impulse via the accessory pathway. The location of the current dipole as determined by analysis of the isomagnetic map at the peak of the T wave in lead II was nearly the same as the position of the current dipole as determined by analysis of the isomagnetic map 40 msec after onset of the delta wave.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

[A case of lymphocytic adenohypophysitis associated with sarcoidosis of the lung and eye].

Lymphocytic adenohypophysitis is considered to be an inflammatory disease of the adenohypophysis that is commonly present with visual disturbance and hypopituitarism. Its etiology remains unclear but it is often related to an autoimmune disorder involving other organs, such as the thyroid, parathyroid, or adrenal glands. We encountered a rare case of lymphocytic adenohypophysitis associated with sarcoidosis of the lung and eye during the follow-up period. A 23-year-old woman was hospitalized in July 1986, with a one-month history of headache and visual disturbances which began three days after her second normal delivery. On admission, she showed slight visual impairment and had a left temporal superior quadrantanopia. Endocrinological evaluation revealed thyroid and adrenal hypofunction, and low response of human growth hormone to the loading test. A skull X-ray showed normal shaped sella with some erosion of the dorsum. CT scan showed a rounded contrast-enhanced intrasellar mass extending into the suprasellar cistern. MRI (SR: 500/30) showed a homogeneous low intensity mass which contained a small high intensity area on the relative T2-weighted image (2000/50). A biopsy was performed via right frontotemporal craniotomy. The consistency of the resected tissue was firmer than that of pituitary adenoma. Histologically, the tissue showed diffuse lymphocytic infiltration with some normal adenohypophysis. Her postoperative course was uneventful and the visual impairment improved two months later after the operation. Six months after the operation, she was readmitted with complaints of general fatigue and breathlessness. Chest X-ray showed diffuse infiltration throughout both lung fields, but there was no bilateral hilar lymphadenopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

The magnetocardiographic diagnosis of right ventricular diastolic overload.

The diagnosis of right ventricular overload is often difficult by the electrocardiogram (ECG) when it is associated with right bundle branch block (RBBB). In this study, we examined the usefulness of the MCG in diagnosis of right ventricular diastolic overload and clarified the features of the magnetocardiogram (MCG) of patients with right ventricular overload with RBBB. In our previous studies, we found that MCG criteria shows higher sensitivity in diagnosis of right ventricular hypertrophy, but the criteria showed higher false positivity in patients with RBBB without any underlying disease (RBBB group). Therefore, we set different MCG criteria for right ventricular diastolic overload (RVO-d) as follows based on the mean +/- 2SD of the RBBB group: 1) R wave at C-3 (Rc-3)greater than or equal to 25 x 10(-12)tesla, 2) S wave at F-4 (SF-4)greater than or equal to 11 x 10(-12)tesla. In patients with a right ventricular pressure of more than 50 mmHg, the MCG criteria showed higher sensitivity and specificity than the ECG criteria. These results suggest that the MCG is useful for diagnosis of right ventricular diastolic overload with RBBB.

Adult↗
PubMed1990

[Basic and clinical studies on norfloxacin in the pediatric field].

Pharmacokinetic , bacteriological and clinical studies on norfloxacin (NFLX), a quinolone-carboxylic acid antibacterial agent, were conducted in the pediatric field. 1. Serum concentrations and urinary excretion of NFLX after single dose of 2.2 approximately 5.6 mg/kg (mean 4.4 +/- 1.2 mg/kg) were determined in 13 children with ages between 6 and 11 years. The mean peak serum concentration of the drug was 0.37 +/- 0.20 micrograms/ml at 2 hours after administration. The mean half-life of the drug in serum was 2.8 +/- 0.4 hours and the serum concentration at 8 hours was 0.11 +/- 0.06 micrograms/ml. The mean urinary concentration reached a maximum of 125.2 +2- 166.2 micrograms/ml in pooled urine from 0 to 2 hours and the mean urinary recovery rate in the first 8 hours after administration was 22.1 +/- 6.0%. A dose-response relationship was observed between doses/body weight and peak serum concentrations. 2. The clinical efficacy, bacteriological efficacy and the safety of NFLX were evaluated in 65 pediatric patients with ages between 2 years 10 months and 15 years 7 months with infections. In 62 assessable cases (acute purulent tonsillitis 9 cases, acute pneumonia 3 cases, chronic rhinitis 1 case, urinary tract infections 15 cases, and acute colitis 34 cases), clinical efficacies were excellent in 48 cases, good in 13 cases, and fair in 1 case with an overall efficacy rate of 98.4%. Staphylococcus aureus 1 strain, Staphylococcus epidermidis 1 strain, Escherichia coli 10 strains, Salmonella sp. 5 strains, Morganella morganii 1 strain, Pseudomonas aeruginosa 3 strains, Haemophilus parainfluenzae 1 strain and Campylobacter jejuni 12 strains were isolated from the patients as pathogens. Bacteriologically, all of these strains were eradicated except that 3 strains of C. jejuni only decreased. With regard to side effects, dizziness and nausea were observed in 1 case each but they were slight and the continuation of the treatment was possible. No abnormal laboratory test data were observed. From the above results, NFLX was considered to be a useful drug for the treatment of pediatric infections.

Adolescent↗