Search PubMed⌕ Search

Biomedical subjects

H Handa

Publications and source records attributed to H Handa.

At least 469 records · Page 26Linked to original sources
PubMed1982

[Clinical evaluation of artificial blood substitute (fluosol-DA 20%) in patients of cerebral ischemia].

The efficacy of perfluorochemicals (Fluosol-DA 20%) as an erythrocyte substitute and the changes of regional cerebral blood flow (r-CBF) following the administration of Fluosol-DA were studied. Seventy-three patients suffering from cerebral ischemic diseases were treated by 10 m/kg of Fluosol-DA. Intravenous infusions were performed 126 times. Clinical efficacy could be estimated by neurological signs, r-CBF and EEG findings in 53 patients who were in acute or subacute stage of diseases. These patients were classified into three groups; 1) Vasospasm group consists of 21 patients and 43 times of infusion, 2) Stenosis or occlusion group consists of 21 patients and 29 times of infusion, and 3) Others. Improvement occurred in 65.1% and 65.5% of vasospasm, and occlusion group, respectively. No aggravated case was noted. One out of 126 infusions showed an exanthema. Changes of r-CBF was measured in 20 cases on 32 hemispheres by either inhalation or intra-arterial infection of 133Xenon. r-CBF was increased 25.0% after the administration of Fluosol-DA when measured by intraarterial injection of 133Xenon. The increase of 16.9% in r-CBF was found in 11 cases by the inhalation method. These values were well correlated with that of animal study using monkeys measured by hydrogen clearance method. From the comparison of the effect of Fluosol-DA and Hespander on r-CBF, the mechanism of increased r-CBF by Fluosol-DA 20%, which contains 2.9% of hydroxyethyl-starch, was considered to be not solely due to the lowering of blood viscosities but also due to the dilating effect on cerebral vessels.

Adolescent↗
PubMed1982

[Nuclear magnetic resonance (NMR) imaging of brain edema from sliced rat brain: preliminary report].

A series of the sliced rat brain were imaged by proton nuclear magnetic resonance (1H-NMR) using a Carr-Purcell-Meiboom-Gill sequence. The slices were obtained from the adult male Wistar rats, normal or suffering from vasogenic brain edema at 2, 6, 24Hr, 2Wk and 2Mo period after the application of cryo-injury. The imaging time was arranged 17 to 22 minutes dependently upon signal to noise ratio. The slice thickness was 1.2 mm, and pixel dimensions were 0.2 X 0.2 mm. Whereas a voxel size in our images is mere 1/1,200 compared to that reported about the prototype human NMR imaging devices, high resolution has been realized. The spatial resolution is very fine, as evidenced by the appearance of major internal structures of rat brain, and the object contrast is so high that cerebral white-gray contrast is excellent, although the difference in water concentration between them is only 7%. It has been impossible to measure serially in vivo change in water concentration of small organs as rat brain, NMR has the capability to generate images in response to tissue state of hydration, therefore we can easily recognize the extent and intensity of the brain edema, which has been defined as an expansion of the brain volume resulting from an increase in its fluid content. And in this study, using the prototype mini-NMR-CT of excellent spatial and contrast resolution, we have been able to show this advantage of NMR as a new tool for research in the field of neurological surgery.

Animals↗
PubMed1982

[Intracranial pressure pulse waveform: considerations about its origin and methods of estimating intracranial pressure dynamics].

Epidural pulse waveform is important as an indicator of intracranial pressure (ICP) dynamics. In this study, the origin of epidural pulse and the clinical implication of its waveform were investigated, using anesthetized artificially ventilated dogs. For this purpose, a cortical artery and a vein were cannulated, and the pressures were recorded simultaneously with epidural pressure (EDP), epidural pulse waveform (EDP-WF), systemic arterial pressure measured in a carotid artery (SAP), central venous pressure (CVP) and electrocardiogram. EDP-WF is composed of several initial peaks and a small delayed peak on the descending limb. The former peaks were slightly delayed from the SAP pulse and were synchronous with the cortical arterial pulse. The latter peak was synchronous with the atrial "a" wave on CVP, but not with the cortical venous pulse. Moreover, the cortical venous pulse was quite similar to EDP-WF. These findings indicate that the pulsation of the brain may be generated by the pulsatile arterial blood flow into the brain, which also affected the pulsation of the cortical vein. The latter peak which was considered to be of venous origin may reflect the dynamics of venules in the brain, not of the cortical vein. Increase of ICP by constant inflation of the epidural balloon or inhalation of CO2 cause EDP-WF monotonous. It is possible that the transmission of arterial pulse into the brain was augmented because of the tightness of the brain or decrease of cerebral vascular tone, although the cortical arterial pressure was not significantly changed or was even slightly decreased. Using a bolus injection technique, the change of EDP-WF in cats was compared with volume-pressure response (VPR) and pulse pressure (PP) which are reported to be good indicators for ICP dynamics. At about 30mmHg, EDP-WF became monotonous while VPR or PP showed only linear relationships with EDP up to 50 to 60 mmHg. Therefore EDP-WF may provide useful information about ICP dynamics in a relatively lower pressure range which could not be detected by VPR or PP study.

Animals↗
PubMed1982

[Parenteral administration of diphenylhydantoin in the pre- and post-operative course on plasma level measurement].

In the neurosurgical care, postoperative convulsion, the especially in the early postoperative course, is one of major complications because it can spoil an otherwise good surgical result. The present study was intended to investigate the prophylactic use of anticonvulsants on chemical measurement of their plasma levels. Parenteral diphenylhydantoin (DPH) given just before craniotomy failed to maintain high level of DPH in the postoperative course even with pretreatment of oral DPH. On the other hand, preoperative oral phenobarbital administration maintained fairly high level in spite of no prescription on the operative day. Intravenous DPH of 250 mg immediately after craniotomy resulted in fairly high level of DPH throughout the early postoperative course in cases of pretreatment of oral DPH. In reviewing the pharmacokinetics of anticonvulsants, the prophylactic use of anticonvulsants in the early postoperative course was discussed.

Adult↗
PubMed1981

Transcription of Simian virus 40 DNA in a HeLa whole cell extract.

Extracts of HeLa cells containing RNA polymerase II and other factors recognize specific sites on linear simian virus 40 (SV40) DNA for initiation of transcription. The most prominent RNA products transcribed from the early region of SV40 and th E strand are initiated at sites 0.67 and 0.655 on the SV40 map. These two RNAs are synthesized by polymerase II. Their 5' termini were positioned by sizing transcripts that extend from the initiation site to the end of the template restriction endonuclease fragment, and by S1-nuclease mapping of unlabeled RNA using DNA probes labeled at their 5' termini. The limit of resolution of mapping of 5' termini is approximately 25 nucleotides. RNAs with 5' termini at similar positions have been found during characterization of mRNAs produced in infected cells. Thus, the whole cell extract is probably initiating transcription on linear SV40 DNA in vitro at the same sites as RNAs synthesized in vivo. Two other processes frequently involved in mammalian cell mRNA biosynthesis, creation of specific 3'-terminal polyadenine tracts and RNA splicing, were not detected during the course of these studies.

Cell Transformation, Viral↗
PubMed1981

Blood compatibility of hydrophilic polymers.

Blood compatibility has been studied for hydrophilic polymers such as poly(vinyl alcohol) (PVA), its derivative, and polyethylene grafted with water-soluble monomers. The surfaces in contact with electrolyte solutions have been characterized by measuring the zeta potentials. The study of plasma protein adsorption on these polymers has revealed that bovine serum albumin as well as bovine serum fibrinogen adsorbs to a lesser extent as the hydrophilicity of the polymers increases. Platelet deposition and fibrin formation, examined using platelet-rich plasma, have been found to take place less significantly on PVA as well as sodium acrylate- and acrylamide-grafted polyethylene than on nongrafted and acrylic acid-grafted polyethylene. Ex vivo experiments with canine whole blood have shown that formation of thrombus on PVA is less than on siliconized glass but increases upon heat treatment which reduces the hydrophilicity. When PVA tubes of about 1 mm diameter are anastomosed to the carotid artery of rat, the patency rate is found to depend strongly on the anastomotic technique. From the results on the zeta potential and the experiments in vitro and ex vivo it can be concluded that the material having a surface from which solvated, neutral chains are extended into the outer aqueous phase may exhibit excellent resistance to thrombus formation.

Adsorption↗
PubMed1981

The significance of periventricular lucency on computed tomography: experimental study with canine hydrocephalus.

In order to investigate the pathogenesis of periventricular lucency (PVL) in hydrocephalus, CT scans were performed with monitoring of the epidural pressure in a series of dogs with hydrocephalus induced with kaolin. PVL of various degrees was detected in the experimental animals, which disappeared immediately after a shunting operation. Correlations have been attempted between PVL on CT scans and histological examinations, contrast enhancement studies, metrizamide ventriculography, and measurement of regional cerebral blood flow in the periventricular white matter. PVL in hydrocephalus is considered to represent acute edema or chronic CSF retention in the periventricular white matter caused by an increase of water content. In other words, it is regarded as a sign of existing or preceding intraventricular hypertension on CT scan, and seems to be a reversible phenomenon to some extent. PVL may therefore became an indication for a shunt.

Animals↗
PubMed1981

Experimentally induced cerebral aneurysms in rats: VII. Scanning electron microscope study.

The luminal surfaces of experimentally induced cerebral aneurysms and the branching sites in the circle of Willis in rats were investigated by scanning electron microscopy. Gap formation at the junctions of the endothelial cells was one of the most obvious changes on the endothelial surface of the aneurysms. Many leukocytes were observed adhering to these gaps. Regressive changes of endothelial cells, such as balloonlike protrusions and craterlike depressions, were also found in the aneurysms. At the branching site, where cerebral aneurysms often develop, endothelial cells were disarranged, rounded, and varied in size. A deep groove was also found adjacent to the apex. The role of endothelial cells and leukocytes in the development of cerebral aneurysms is discussed.

Animals↗
PubMed1981

Vanishing cerebral aneurysm in serial angiography.

The angiographically documented spontaneous thrombosis of an internal carotid-posterior communicating aneurysm in a 63-year-old woman is reported. Serial angiography performed 10, 17, and 29 days after the initial attack of subarachnoid hemorrhage demonstrated progressive thrombosis of the aneurysm. Clinical analysis of this case and a review of the literature suggest that vasospasm and the relative narrowness of the aneurysmal neck played crucial roles in the spontaneous thrombosis of the aneurysm, although neither is definitely responsible.

Adult↗
PubMed1981

Quantitative analysis of microstructural components of human cerebral arteries.

Microstructural components were analyzed quantitatively by means of a microphotometric technique applied to three kinds of major cerebral arteries and two kinds of extracranial arteries of comparable size obtained from human autopsy subjects. No statistically significant difference was found in the fractions of three structural components, elastin (Fe), collagen (Fc), and smooth muscle (Fm), in the total of fractions of these three components and in the ratio between extracranial arteries. The Fe-values were significantly less in cerebral arteries than in extracranial arteries. The Fc/Fe ratios in cerebral arteries were about triple those in extracranial arteries. Although there was no statistically significant difference in the Fe- and the Fm-values between the two age groups, under 49 and over 50 years old, the Fc/Fe ratio were higher in the older age group. This change of microstructural composition with age was more prominent in cerebral arteries than in extracranial arteries.

Adult↗