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Biomedical subjects

Y Chiba

Publications and source records attributed to Y Chiba.

At least 235 records · Page 13Linked to original sources
PubMed1990

Evaluation of fetal structural heart disease using color flow mapping.

The technique of color flow mapping was used to diagnose 19 cases of fetal structural heart disease from a study group of 104 fetuses. Color flow mapping was 76% effective in detecting the presence of fetal structural heart disease. The colored views of a single stream in the atrioventricular canal were most impressive in cases of complete atrioventricular canal, hypoplastic left heart syndrome, mitral atresia, and tricuspid atresia. The colored views of tricuspid regurgitation were also clear in cases of endocardial fibroelastosis, pulmonary atresia with intact ventricular septum, and Ebstein's anomaly. The use of this technique resulted in the in-utero diagnoses coinciding more closely with the final diagnoses, which were made after birth. This was particularly important in those cases which required immediate management after birth.

Echocardiography, Doppler↗
PubMed1990

Correlation between structures of organic cations and their binding behaviours to brush border membrane isolated from rat small intestine.

We have investigated the correlation between the molecular structures of various organic cations and their binding to rat small intestinal brush border membrane. The binding of small quaternary ammonium compounds such as tetramethylammonium and choline to brush border membrane was not sufficient to inhibit methylchlorpromazine binding. However, lauryltrimethylammonium and cetyltrimethylammonium, both quaternary amines with a long carbon chain, inhibited binding significantly. The inhibition was competitive. When the unbranched hydrocarbon chain of the quaternary amines was extended in steps from C1 (methyl) to C16 (cetyl), the inhibitory effect increased sharply with length from C7 (heptyl) to C16. These results suggest that the size of the hydrophobic part of the molecule is an important factor in binding of quaternary ammonium compounds to the brush border membrane. The structure of the hydrophilic part was another factor. In imipramine-related compounds, the order of binding was N-didesmethylimipramine (primary amine) greater than desipramine (secondary) greater than imipramine (tertiary) greater than methylimipramine (quaternary). However, with the small molecular ethylamine-related compounds, binding properties did not reflect differences in the hydrophilic component. Therefore, the effect of the hydrophilic part may be secondary and may depend on the size of the hydrophobic part. We suggest that organic cations which are amphiphilic can bind to a common binding site on brush border membrane through hydrophobic and/or hydrophilic interactions.

Animals↗
PubMed1990

Evaluation of the preload condition of the fetus by inferior vena caval blood flow pattern.

Using pulsed Doppler ultrasound, blood flow in the inferior vena cava (IVC) was studied in 47 normal fetuses from 24 to 40 weeks of gestation and 35 abnormal fetuses, with the exception of those with arrhythmias. The abnormal fetuses were divided into 4 groups according to diagnosis, i.e., 6 cases of heart disease with hydrops (group 1), 9 cases of heart disease without hydrops (group 2), 11 cases of hydrops without heart disease (group 3), and 9 cases of other fetal diseases (group 4). By measuring the velocity of IVC blood flow, we defined a new index, the change in parallel with reverse flow velocity, and called it the preload index (PLI). In normal fetuses, PLI values ranged from 0 to 0.37 and had no relation with gestational age. The PLI was significantly higher in groups 1-3 than in normal fetuses. In group 1, the PLI was also higher than in group 2. In group 3, the PLI values in 4 cases of chylothorax, 1 of chyloascites and 1 of cytomegalovirus infection were significantly lower than in the remaining 5 cases where the cause of hydrops was undetermined. The PLI was normal in 9 fetuses with other diseases and no hydrops. The PLI was increased in conditions in which excessive preload, tricuspid regurgitation, or some kind of structural heart disease were present.

Blood Flow Velocity↗
PubMed1990

Quantitative analysis of cardiac function in non-immunological hydrops fetalis.

The present study was designed to quantitatively evaluate fetal cardiac dysfunction in fetal congestive heart failure associated with cardiogenic hydrops fetalis. Thirty-seven cases of non-immunological hydrops fetalis and/or fetal heart disease were assigned to four groups: (1) hydrops fetalis with structural heart disease; (2) hydrops fetalis without heart disease; (3) structural heart diseases without hydrops, and (4) complete A-V block without hydrops. One hundred and ten control fetuses were also studied. The ejection fraction in the first and third groups was significantly lower than that in the control. In the first group, systolic flow velocity in the descending aorta normalized but gestational age was significantly lower than that in the controls. Compensation of fetal cardiac function in the fourth group (complete A-V block) was noted on the basis of higher flow velocity and higher contractility. The cardiothoracic area ratios of the pathological and control groups were also evaluated.

Female↗
PubMed1990

Distribution of circadian photoreceptors in the compound eye of the cricket Gryllus bimaculatus.

Adult male crickets (Gryllus bimaculatus) show a nocturnal circadian locomotor rhythm, which is driven by the pacemaker in the optic lamina-medulla complex and synchronizes to the light-dark (LD) cycle received by the compound eye. To see whether there was any specially differentiated circadian photoreceptor area in the eye, we examined the effect of a partial reduction of various areas of the compound eye, in addition to a removal of the contralateral optic lamina-medulla-compound eye complex, on entrainability of the locomotor rhythm. All operated animals showed a response to the LD cycle in their locomotor rhythm, no matter which area of the eye was left intact: They either stably entrained to an LD cycle or showed a sign of weak entrainment. The capacity for stable entrainment was still retained when only 262 ommatidia were left. Transient cycles needed for re-entrainment, following a 6-hr phase advance of the LD cycle, were measured in 20 reduced-eye animals showing clear stable entrainment. They were in inverse proportion to the number of ommatidia in the reduced eye: The fewer ommatidia there were, the more transient cycles were observed (r = -0.76, p less than 0.001). These results suggest that almost the whole area of the compound eye may contain circadian photoreceptors, and that the photic information from each ommatidium may additively affect the circadian clock to entrain via neural integration mechanisms.

Animals↗
PubMed1990

A computer-based behavior monitoring system for low-birth weight infants under intensive care.

For the intensive care of low-birth weight infants, it is important to continuously monitor behavioral changes. From this point of view, we have developed a computer-based monitoring system to analyze the body movements of low-birth weight infants under intensive care. The system consisted of a video recorder with a micro CCD camera for observing infant's body movements and a real time image processor for analyzing video frames. A 16 bit personal computer equipped with an image processor converted a video frame into a binary image that is a 256 by 256 matrix of pixels. The computer assessed each pixel of the matrix to determine whether the brightness changed between successive binary images or not. The number of changed pixels was counted every 1/30 sec, and such change reflected a infant's body movements. Using the system, body movements of a low-birth weight infant in an incubator were videotaped during 24 hours and analyzed. Results indicate that the behavior monitoring system developed in the present study has not only the ability to detect occurrences of movements of low-birth weight infants, but also the ability to qualitatively describe the pattern of movements.

Female↗
PubMed1990

Glomerular filtration response to acute loading with protein from different sources in healthy volunteers and diabetic patients.

To evaluate the effects of acute protein loading on the glomerular filtration rate, albumin excretion rate and concentration of plasma amino acids, ten healthy volunteers and six type 2 diabetic patients with normoalbuminuria were studied before and after eating 0.7 g/kg body weight of tuna fish, boiled egg white, cheese or tofu (bean curd) on separate days. Furthermore, to study the possible role of glucagon, growth hormone, atrial natriuretic peptide and kallikrein in the responses of glomerular filtration rate to protein, these substances were measured before and after ingestion of tuna fish or egg white in six healthy volunteers. In healthy subjects, glomerular filtration rate increased significantly (p less than 0.01) from 98.1 +/- 4.2 ml/min during the baseline period to 129.9 +/- 6.6 ml/min after ingestion of tuna fish. No significant differences were seen between glomerular filtration rate before and after ingestion of egg white, cheese or bean curd. No significant differences were observed between the baseline albumin excretion rate and that after loading with any of the four kinds of protein. Plasma concentrations of alanine, glycine and arginine (amino acids known to induce glomerular hyperfiltration) increased to a greater degree after ingestion of tuna fish than after administration of the other meals. Diabetic subjects and healthy volunteers had similar responses. Plasma glucagon and growth hormone concentrations increased after ingestion of the tuna fish meal or egg white. Plasma atrial natriuretic peptide concentration and urinary kallikrein excretion were unaffected by ingestion of these two kinds of protein. These findings suggest that responses of glomerular filtration rate to acute protein loading may differ depending on the protein ingested, and that these responses may not be directly induced by glucagon, growth hormone, atrial natriuretic peptide or kallikrein.

Adult↗
PubMed1990

Multicentric intracranial fibrous xanthoma--case report.

Intracranial fibrous xanthoma is extremely rare; only 11 cases have been reported so far. The authors report a case of multicentric intracranial fibrous xanthoma. Precontrast computed tomographic (CT) scans revealed a left frontal subdural mass, which had previously been diagnosed as a chronic subdural hematoma at another hospital. However, operation disclosed no hematoma but a granulomatous tumor. The biopsied specimen was histologically diagnosed as fibrous xanthoma. Postoperative postcontrast CT scans showed intense homogeneous enhancement at the clival and the left frontal regions, both of which appeared as iso- to low-intensity areas on T1-weighted magnetic resonance (MR) images and as low-intensity areas on T2-weighted MR images. She gradually recovered by conservative treatment but suddenly died of cerebral infarction. Autopsy revealed fibrous xanthomas in the left frontal and the clival regions. This is the first report of the use of MR imaging for intracranial fibrous xanthoma, and its features differ from those of common intracranial parenchymal tumors, MR imaging can be helpful in the diagnosis of this tumor.

Aged↗
PubMed1990

[A case report of descending thoracic aortic aneurysm associated with anterior spinal artery syndrome despite no marked ESP changes].

A 67-year-old man underwent graft replacement for the descending thoracic aortic aneurysm with the aid of temporary external bypass. Intraoperative evoked spinal potentials (ESPs) were monitored to detect the spinal cord ischemia. Incomplete paraplegia with sensory dissociation was developed in this patient after surgery, despite well maintained ESPs throughout the aortic cross-clamping. ESPs have been widely used as a mean of detecting early impairment of spinal neural conduction during aortic surgery. However, ESPs are principally mediated through posterior and lateral column pathways and they are not always a reliable monitor to predict paraplegia in aortic surgery.

Aged↗
PubMed1990

[Management results of primary intracranial malignant lymphoma].

Nineteen cases of primary malignant lymphoma of the central nervous system were reported. The clinical characteristics, diagnostic procedure and therapeutic method, especially concerning chemotherapy, were analysed. The following conclusions were obtained: 1) histological classifications and surgical procedures were not factors involved in prognosis. 2) radiotherapy was regarded as an effective but a palliative treatment. 3) combined chemotherapy for systemic malignant lymphoma, such as VEMP, VEP, COPP, seemed to be of little use for intracranial malignant lymphoma. 4) intra-arterial administration of high-dose methotrexate, ACNU and intravenous administration of high-dose cytosine arabinoside can be expected to be a useful chemotherapeutic approach.

Adolescent↗
PubMed1990

[A case of infective endocarditis with hemorrhagic fibrinous pericarditis].

A case of infective endocarditis which was complicated with hemorrhagic fibrinous pericarditis was reported. The hemorrhagic fibrinous pericarditis is a rare complication of infective endocarditis of the aortic root and is observed massive hemorrhage into the pericardial space. These patients should be considered for the aortic valve replacement early in the course of the disease.

Aortic Valve↗
PubMed1990

[A case of mediastinal neurinoma originating from right intrathoracic vagal nerve].

A 34-year-old woman was admitted with an abnormal shadow on a chest X-ray film. Under a preoperative diagnosis of benign bronchogenic cyst, operation was carried out and the tumor was found to be originating from the right main vagal nerve in the mid-superior mediastinum. The vagal nerve was transected to remove the tumor. Pathological diagnosis was a neurinoma. Postoperative complication was chylothorax which was successfully treated with thoracic drainage and intravenous hyperalimentation.

Adult↗
PubMed1990

[An operated case of ectopic thymic cyst of the posterior mediastinum].

We reported an operated case of thymic cyst of the posterior mediastinum, whose common location in the mediastinum is anterior or antero-superior portion. A 58-year-old female was admitted because of the abnormal shadow on a routine chest radiograph. No particular symptoms and physical findings were noticed. The CT scanning and the MR Imaging of the thorax demonstrated the posterior mediastinal mass, which was removed by thoracotomy. The histopathological findings were most consistent with a diagnosis of thymic cyst. No cases of ectopic posterior mediastinal thymic cyst have been described in the recent literature.

Female↗
PubMed1989

Comparative platelet anti-aggregant activity of D-cysteinolic acid analogues.

D-Cysteinolic acid (1) analogues with an S-C-C-N skeleton showed increased platelet anti-aggregant activity in the following order: 2-aminoethanesulfonic acids, thiazolidines, 2-aminoethanethiols and 2-aminoethyl disulfides. Methyl substitutions at the 2-position potentiated the activity. Of these analogues, bis [(R)-2-aminopropyl] disulfide was the most potent inhibitor of platelet aggregation, with about 600-fold the activity of (1).

Animals↗
PubMed1989

Induction of angiotensin-converting enzyme inhibitory activity by acid-limited proteolysis of glyceraldehyde 3-phosphate dehydrogenase.

Angiotensin-converting enzyme (ACE) inhibitors were excised from glyceraldehyde 3-phosphate dehydrogenase (GAPDH) preparations of tuna and porcine muscles by heating at 120 degrees C for 5 min in 1 M AcOH-20 mM HCl. The inhibitors were then purified by successive chromatographies. The final product from tuna was identified as Pro-Thr-His-Ile-Lys-Trp-Gly-Asp, which was the ACE inhibitor obtained from tuna muscle [Kohama et al. (1988) Biochem. Biophys. Res. Commun. 155, 332-337]. The porcine ACE inhibitor was found to be Pro-Ala-Asn-Ile-Lys-Trp-Gly-Asp, which was identical to the porcine muscle GAPDH peptide 79-86. These results strongly suggested that the ACE inhibitory octapeptides derived from GAPDH proteins by acid-limited proteolysis at Asp-Pro and Asp-Ala peptide bonds.

Amino Acid Sequence↗