Teratoma in the pineal region in two brothers. Case reports.
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Adolescent↗
Biomedical subjects
H Segawa
Publications and source records attributed to H Segawa.
Relation of cerebral blood flow to neurological status and outcome in head-injured patients.
Noninvasive studies of regional cerebral blood flow (CBF) were performed on 36 head-injured patients in varying degrees of coma, using the intravenous xenon-133 method. Serial examinations, averaging four per patient, were begun during the acute phase of illness and continued until death of recovery of normal consciousness. Comparison of the initial and final studies revealed that CBF declined to very low levels in all nine patients who died, and remained subnormal in a patient with persistent vegetative state. In contrast, 25 of 26 patients who recovered consciousness showed increases in blood flow. Because of the presence of both reduced and elevated blood flows on the initial study, CBF was not predictive of outcome. Absolute or relative hyperemia, observed in nine acute cases, was associated with either diffuse cerebral swelling (observed on computerized tomography) or recovery from systemic shock. Cerebral metabolic studies in hyperemic patients yielded a very low oxygen uptake and arteriovenous oxygen difference, indicating that the high blood flow was a true "luxury perfusion." When instances of presumed luxury perfusion were excluded, CBF was positively correlated with level of consciousness, assessed on a four-point coma scale.
Adolescent↗
[Workschedule at the time of insertion of a metreurynter].
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Cervix Uteri↗
Synthesis and properties of an oligonucleotide modified with an acridine derivative at the artificial abasic site.
The synthesis of an oligodeoxynucleotide (ODN) modified with 2-methoxy-6-chloro-9-aminoacridine (Acr) at an abasic site is described. A stereochemically defined aminodiol, L-threoninol, was used to serve as artificial abasic nucleoside. The molecule was modified so as to be suitable for the standard phosphoramidite method and was incorporated into the interior of an ODN. In addition, N-hydroxysuccinimidyl N-[9-(6-chloro-2-methoxy)acridinyl]-6-aminocaproate has been synthesized for postsynthetic modification of the amino substrate of the L-threoninol moiety in the ODN. By using absorption spectroscopy, it is shown that oligo(dA) conjugated with acridine binds with complementary strand in a 1:1 ratio. The melting temperature showed that the nonmodified (abasic) duplex is destabilized as a result of lacking in base at the abasic site, but the covalently linked acridine ring compensates for the destabilization effect. The fluorescence quantum yield of the acridine ring was enhanced by connection to oligo(dA) and, further, by formation of a double-strand with the complementary ODN. The quantum yield is larger than that of intermolecular intercalation. The excitation spectra of Acr-ODN in the duplex is quite similar to the absorption spectra. The results indicate that the covalently linked acridine ring is selectively intercalated into the adjacent abasic site.
Acridines↗
Computed tomographic measurement of local cerebral blood flow by xenon enhancement.
The present technique was developed to overcome some of the disadvantages of measuring cerebral blood flow by radionuclide methods, such as poor localization of flow values and errors that result if the brain is pathological and local partition coefficients are altered. Serial CT scanning in humans was carried out during and after inhalation of 50 to 70% non-radioactive xenon. This diffusible gas with high atomic number enhanced gray matter first by 19 +/- 4 Hounsfield Units (HU) and later white matter by 24 +/- 4 HU. The regionality of flow values were cursored on CT pictures with a high spatial resolution of 4 X 4 mm (64 pixels) or 0.16cm2 X 0.5cm. In seven normal subjects, blood flow in gray matter was 82 +/- 11 ml/100gm/min and that in white matter 24 +/- 5ml/100gm/min. The partition coefficient (lambda), which is not obtainable in vivo by radionuclide scanning, was 0.9 +/- 0.1 for normal gray matter, 1.4 +/- 0.2 for normal white matter. Reduced flow, 13% in gray matter and 46% in white matter, was found in a large infarct secondary to complete occlusion of middle cerebral artery. In edematous tissue, blood flow was not significantly impaired in gray matter but was reduced to 29 to 54% in white matter. Local lambda values were reduced to 0.6-0.9 in edematous tissue, and 0.3-0.7 in infarction. This method appears to have several advantages over conventional isotope methods of measuring cerebral blood flow and provides useful clinical and research information.
Adult↗
Middle cerebral artery occlusion: correlation of computed tomography and angiography with clinical outcome.
The clinical outcome of 40 cases with middle cerebral artery (MCA) occlusion was examined in relation to the site of occlusion and the findings on computed tomography (CT). Patients were treated conservatively without surgery. A few had decompressive craniotomy when necessary. Outcome in 7 (18%) was good, in 6 (15%) moderate, and in 15 (38%) severe; 12 (30%) died by the follow-up at 3 months. In cases with occlusion at the origin of the MCA, hypodensity on CT scan was usually localized to the basal ganglia, presumably because of collateral circulation through the anterior cerebral arteries; the outcome in these patients was not always favorable. Cases with occlusion of the trunk or branch vessels always showed marked CT hypodensity, and clinical outcome was poor. To assess quantitatively the extent of collateral circulation, the conduction time of contrast medium from the intracranial siphon (IC) to the insular portion of the MCA (M2) through the anterior cerebral arteries was calculated on serial carotid angiograms obtained within 24 hours after stroke onset. An IC-M2 time of 5 seconds was a critical indicator of whether extensive CT hypodensity would develop (the rule of 5 seconds). Furthermore, this method predicted the appearance and extent of infarction before CT revealed hypodensity. The significance of acute reconstructive surgery is also discussed.
Aged↗