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Biomedical subjects

E Nakai

Publications and source records attributed to E Nakai.

At least 37 records · Page 2Linked to original sources
PubMed1990

Stereotactic hyperthermia for brain tumors.

We have developed a localized hyperthermia system using computed tomography-stereotactic surgery as malignant brain tumor therapy. In an experimental study, the temperature in the area of the cat brain within 20 mm from a radiofrequency electrode reached more than 43.7 degrees C. Intravenous administration of MCNU during hyperthermia caused a significant increase of MCNU content in the heated brain as compared with a control brain. In the clinical study, localized radiofrequent hyperthermia using stereotactic surgery was performed on 7 malignant deep-seated gliomas and 21 metastatic brain tumors. Especially, combination therapy of stereotactic hyperthermia and chemotherapy was effective treatment for gliomas less than 30 mm deep in the brain.

Adolescent↗
PubMed1989

Stereotactic evacuation of hypertensive cerebellar hemorrhage using plasminogen activator.

Treatment for hypertensive cerebellar hemorrhage still remains controversial as to whether direct surgical procedure is indicated or not. This is so even after the introduction of CT scan which easily demonstrates the location and size of the hematoma and the presence of hydrocephalus. In this paper, we present our experience of 20 patients with cerebellar hemorrhage treated by stereotactic evacuation using Komai's CT-stereotactic apparatus. All the patients had vertigo, cerebellar symptoms, dysfunction of brain stem or consciousness disturbance. The hematomas on CT scan were more than 28 mm in diameter. Acute obstructive hydrocephalus occurred in 90% of the patients with hematoma 40 mm or larger in size. The patients with consciousness disturbance were immediately operated on after the attack, and a drainage tube was placed in the hematoma cavity to drain cerebrospinal fluid and liquefied hematoma for one to eight days. On the other hand, when patients with hematoma around 30 mm in diameter complained vertigo for about two weeks, they also were operated on stereotactically. After the operation, their symptoms improved rapidly. The stereotactic operation could aspirate about 85% of the estimated hematoma volume and improved the hydrocephalus, except in one case in which the patient rapidly deteriorated to coma level with a large cerebellar hemorrhage and brain stem damage. This stereotactic evacuation of cerebellar hematoma using a plasminogen activator is effective for not only the removal of hematoma, but also for the treatment of secondary hydrocephalus following obstruction of the fourth ventricle by cerebellar hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Three-dimensional correlation between auditory brainstem response and auditory tract in hypertensive pontine hematoma].

A three-dimensional reconstructed display using a microcomputer represents the spatial correlation between the nuclei of auditory tract and pontine hematoma. Stereotaxic evacuation of hematoma was performed on seven cases of pontine hemorrhage. By making a comparison between preoperative and postoperative findings of ABR and this display, we examined the effect of the surgical intervention on ABR findings. ABR was recorded according to the standard way (100 dBSL, 2000 click stimuli). Hematoma was drawn on the Atlas of the Human Brainstem and Cerebellar Nuclei by Farhad Afshar. The data plotted on digitizer was inputted and processed under our computer program that enables the brainstem and hematoma visualized and rotated three-dimensionally at our option. The results were as follows: a) ipsilateral dominance in human auditory tract in terms of the origin of ABR waves, b) delayed latency time of wave II which was supposed to be based on an influence upon the ipsilateral superior olivary nucleus, c) that of wave III upon the ipsilateral lateral lemniscus, d) four cases of them showed an improvement of I-III interpeak latency time, which suggested the decompressive effect on caudal aspect of pons.

Adult↗
PubMed1986

Mode of cell growth of Malassezia (Pityrosporum) as revealed by using plasma membrane configurations as natural markers.

The mode of cell growth of Malassezia was studied by freeze-fracture using the plasma membrane configurations of this organism as natural markers. The plasma membrane of the mature cell bodies of M. pachydermatis had a ring swelling, and on each side of the ring, one set of straight and spiral grooves and circumvallate bulgings. The cell always divided at the ring swelling (M. pachydermatis) or depression (M. furfur), soon followed by budding there. A new set of similar configurations formed on the bud. In all the 12 strains of Malassezia studied, the spiral grooves in the mother and bud parts were both left-handed but opposite in the direction of elongation. By comparing distances between the spiral grooves in short and long buds and in mothers, the bud tip was suggested as the major, and adjacent regions as the minor, sites of wall growth. Some characterizations of the plasma membrane invaginations, especially in relation to the mode of cell growth, were also described.

Cell Membrane↗
PubMed1986

[Stereotactic evacuation of hypertensive thalamic hematomas using plasminogen activator (urokinase)].

In the past five years, the authors have performed stereotactic evacuation of hypertensive thalamic hematoma using Komai's CT-stereotactic apparatus in 44 cases. Liquefied hematoma was aspirated through a stereotactic cannula, and solid hematoma difficult to aspirate was dissolved by a plasminogen activator (Urokinase) and drained out through a silastic catheter. The mean ratio of the total volume of evacuated hematoma to the estimated volume by CT image was 83.8%. The recovery from motor paresis and consciousness disturbance was observed during the early postoperative days in most patients. Functional outcome (ADL) at 3 months after operation was as follows: 24 cases (54.5%) recovered to a full or partial (self-cared) social life, 15 (34.1%) required partial care at home and 2 (4.5%) remained bedridden. Although 3 patients died within 1 month after operation, the cause of death in these patients was admitted to have no direct relation to operative procedure or to rebleeding due to the Urokinase injection. Postoperative functional prognosis was not affected by the timing of the operation. The important factors affecting ADL were preoperative neurological grade and CT classification. This stereotactic method apparently exceeded the conventional craniotomy method in the functional outcome.

Adult↗
PubMed1985

Spectrophotometric determination of oxalate in urine and plasma with oxalate oxidase.

In order to establish a standard procedure for the spectrophotometric determination of urinary and plasma oxalate with oxalate oxidase (Laker, M.F., et al. (1980) Clin. Chem. 26, 827-830; Sugiura, M., et al. (1980) Clin. Chim. Acta 105, 393-399) and to define the limitations of the method, the procedures and reactions involved in the assay have been examined. Among the chromogenic hydrogen donors for peroxidase tested, a combination of 3-methyl-2-benzothiazolinone hydrazone (MBTH) and sodium N-sulfopropylaniline (HALPS) was found to be best for the oxalate determination under the conditions used. Urine contained substance(s) which were inhibitory to the measurement of hydrogen peroxide by the peroxidase-catalyzed oxidative condensation of MBTH and HALPS, but they were largely removed by charcoal treatment at pH 5.6 without significant loss of oxalate. Deproteinization of plasma was carried out by ultrafiltration through a membrane cone (Centriflo CF-25) at neutral pH. The plasma oxalate ultrafiltrability under the conditions employed was calculated to be approximately 95%. A standard assay system for oxalate in these urine and plasma samples was then set up based on a series of studies on the reactions involved in the assay. In the case of normal plasma, however, the absorbance change was very small due to the low concentration of oxalate, and in addition, pretreatment of plasma with excess oxalate decarboxylase followed by the ultrafiltration and oxalate determination did not abolish completely the oxalate oxidase-dependent absorbance increase. It was concluded that the enzymic method was useful for the assay of urinary oxalate and in detecting elevated levels of plasma oxalate such as those in hemodialysis patients but was not sensitive enough to determine accurately the normal or decreased level of oxalate in plasma. The apparent concentration of oxalate in normal human plasma was measured in this work as 3.5 +/- 0.8 microM (mean +/- S.D., n = 8), and this result was interpreted to mean that the concentration of plasma oxalate was less than approximately 3.5 microM, as estimated by the present method.

Blood Proteins↗
PubMed1985

Tuberous sclerosis with an atypical radiological skull change: case report.

The authors describe a case of tuberous sclerosis with atypical radiological skull change in a 8-year-old Japanese child. A plain roentgenogram showed thinning and convolution of the left occipital bone, and a cortical tuber adjacent to the thinned bone was shown by computed tomography. This kind of skull change may suggest the existence of a cortical tuber in patients with tuberous sclerosis, although this finding has not been reported previously. The mechanism of this skull change is discussed.

Child↗
PubMed1985

Chronic encapsulated intracerebral hematoma during infancy: case report.

Chronic encapsulated intracerebral hematoma is a rare condition. Only four cases have been reported. The cause of this condition is unclear. A case of chronic encapsulated intracerebral hematoma in an 1-year-old infant is reported, and the characteristic findings and their causes are discussed with a literature survey.

Cerebral Hemorrhage↗
PubMed1984

Relaxant effects of mercury and mercury uptake in the smooth muscle of guinea-pig taenia coli.

Hg2+ (0.005-0.5 mM) induced a concentration-dependent reduction on high-K+-induced contraction of taenia coli. The K+-induced increase in 45Ca uptake was significantly reduced in the presence of Hg2+ (0.05-0.5 mM). The contractions of the glycerinated taenia coli were inhibited by an increase in Hg2+ concentration. Mercury uptake increased along the duration of Hg2+ incubation. When muscles were rinsed with a medium containing 5 mM EDTA after 0.5 mM Hg2+ treatment for 90 min about 30% of the original level of tissue mercury was retained. Possible mechanism for the tension inhibitory action of Hg2+ include: (1) that Hg2+ bound to cell membrane initially interferes with the permeability of Ca2+ and that (2) the cellular mercury fraction that is not eliminated by EDTA subsequently correlates with the tension inhibitory action.

Animals↗
PubMed1984

Freeze-fracture observations of the cell walls and peribacillary substances of various mycobacteria.

Ultrastructure of the cell wall and peribacillary substances of various mycobacteria (32 strains of 18 species) grown in vitro was studied by a freeze-fracture technique. Peribacillary substances differed in shape among species and even among strains of the same species, and were classified into five types: (1) amorphous substances; (2) multi-layered sheaths with no filamentous units; (3) structures composed of filaments of 2-4 nm diameter, which were further classified into three subtypes according to the arrangement of the filaments; (4) helical fibres; and (5) single fibres, or networks of fibrous structures, with no visible substructures. No strains revealed peribacillary structures resembling those of uncultivable Mycobacterium leprae. These results have implications for the mechanism of freeze-fracturing in mycobacterial walls.

Cell Wall↗
PubMed1982

Experimental studies on the pulmonary surfactant. Reconstitution of surface-active material.

The conditions for the reconstitution of surfactant lipoprotein were investigated using pig pulmonary surfactant. Lipids of surface-active material (SAM) were extracted with ethanol-ether and the residue, containing mainly protein, was extracted first with dilute sodium borate buffer (pH 10.0) (fraction A) followed by extraction with deoxycholate solution (fraction B). The former (A) contained mainly protein having a nominal molecular weight of 34,000 daltons, albumin and globulin, and the latter (B) 34,000 and 15,000 daltons. Reconstitution of lipids and proteins using these two fractions revealed a greater affinity of fraction B to lipids than that of fraction A, when lipids and proteins were dialyzed against pH 7.4 Tris-HCl. Observation by freeze-fracture methods revealed that protein particles were incorporated into liposomes. Protein-lipid ratio of this complex (LB) could be regulated by altering the amount of lipids and protein during the dialysis. Fraction A was incorporated into LB (LBA) by dialyzing LB with fraction A at an acidic pH. With this procedure, protein having a nominal molecular weight of 34,000 daltons was selectively incorporated. In negatively stained preparations, LBA had a granular appearance in the area limited by lipid membrane. We suggest that in the lipid-protein complex of SAM, two different proteins are present; a hydrophobic one in lipids and more hydrophilic ones in the water phase that have a close association with the former.

Animals↗
PubMed1977

Freeze-etching observations of Trichophyton Violaceum.

Trichophyton violaceum was cultured on a Sabouraud's dextrose agar slants for freeze-fracture replication. It was cryoprotected with glycerol and sucrose. The surface structure of the cell wall showed a rodlet pattern. Invagination-like craters were observed in the plasmalemma. The nuclear envelope with pores, mitochondria, and vacuoles were clearly shown. Three-dimensional views of the fine structure were presented.

Cell Wall↗
PubMed1977

Freeze-etching observations of Fonsecaea pedrosoi.

The fine structure of Fonsecaea pedrosoi was studied by freeze-etching techniques. The structure of the cell wall as seen in Trichophyton groups was not observed. The invaginations were clearly shown in the plasma membrane. Three-dimensional views of the fine structure were presented.

Ascomycota↗