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Biomedical subjects

R Tanaka

Publications and source records attributed to R Tanaka.

At least 1,027 records · Page 57Linked to original sources
PubMedDate not supplied

Intelligence in children with moyamoya disease: evaluation after surgical treatments with special reference to changes in cerebral blood flow.

The effect of surgical treatment upon the intelligence of 20 children with moyamoya disease was evaluated and related to changes in cerebral blood flow (CBF). The patients were treated by various surgical revascularization procedures, mainly by encephalo-myo-synangiosis. Intelligence was tested using the Wechsler intelligence scale for children (WISC) in 19 children and the Wechsler adult intelligence scale (WAIS) in one child. Measurements of regional CBF were performed by a 133Xe inhalation method. In the preoperative state, the degree of reduction in the intelligence quotient (IQ) correlated well with the age of the patients; the older patients revealed a more marked reduction of IQ, and the patients with lower intelligence scores in general showed a tendency for more marked depression of mean CBF. Postoperatively, most of the patients showed increase in IQ, especially in performance IQ which improved significantly in 10 patients, remained unchanged in 3 and deteriorated in 2. Mean CBF increased by an average of 11.4%, and postoperative changes in mean CBF correlated well with the changes in IQ in most patients. This may show that the postoperative increase in CBF is quite possibly responsible for the changes in IQ.

Adolescent↗
PubMedDate not supplied

High light inhibits chlorophyll biosynthesis at the level of 5-aminolevulinate synthesis during de-etiolation in cucumber (Cucumis sativus) cotyledons.

Using the vascular plant Cucumis sativus (cucumber) as a model, we studied the effects of high (intense and excess) light upon chlorophyll biosynthesis during de-etiolation. When illuminated with high light (1500-1600 microE/m2/s), etiolated cucumber cotyledons failed to synthesize chlorophyll entirely. However, upon transfer to low light conditions (40-45 microE/m2/s), chlorophyll biosynthesis and subsequent accumulation resumed following an initial 2-12 h delay. Duration of high light treatment negatively correlated with chlorophyll biosynthetic activity. Specifically, we found that high light severely inhibited 5-aminolevulinic acid (ALA) synthesis. This effect partly could be because of the decrease in protein level of glutamyl-tRNA reductase (GluTR) observed. Protein level of glutamate-1-semialdehyde (GSA-AT) remained unchanged. It was also found that high light did not suppress HEMA 1 expression. Therefore, we speculated that this significant inhibition of ALA synthesis might have occurred mainly because of concomitant inactivation of GluTR and/or inhibition of complex formation between GluTR and GSA-AT. Our further observation that both methyl viologen and rose bengal similarly inhibit ALA synthesis under low light conditions suggested that reactive oxygen species (ROS) could be responsible for the inhibition of ALA synthesis in cotyledons exposed to high light conditions.

Aldehyde Oxidoreductases↗
PubMedDate not supplied

Accuracy of a portable blood gas analyzer incorporating optodes for canine blood.

The accuracy of a portable blood gas analyzer (OPTI 1) was evaluated using canine blood and aqueous control solutions. Sixty-four arterial blood samples were collected from 11 anesthetized dogs and were analyzed for pH, partial pressure of carbon dioxide (PCO2) partial pressure of oxygen (PO2), and bicarbonate concentration ([HCO3-]) values by the OPTI 1 and a conventional blood gas analyzer (GASTAT 3). The conventional analyzer was considered as a standard against which the OPTI 1 was evaluated. Comparison of OPTI 1 results with those of GASTAT 3 by linear regression analysis revealed a high degree of correlation with the GASTAT 3 (r = .90-.91). The mean +/- SD of the differences between OPTI 1 and GASTAT 3 values was -0.008 +/- 0.017 for pH, -0.88 +/- 3.33 mm Hg for PCO2, 3.71 +/- 6.98 mm Hg for PO2, and -0.34 +/- 1.45 mEq/L for [HCO3-]. No statistically significant difference was found between the OPTI 1 and the GASTAT 3. Agreement between these 2 methods is within clinically acceptable ranges for pH, PCO2, PO2, and [HCO3-]. The coefficients of variation for measured pH, PCO2, and PO2 values of 3 aqueous control solutions (acidic, normal, and alkalotic) analyzed by the OPTI 1 ranged from 0.047 to 0.072% for pH, 0.78 to 1.81% for PCO2, and 0.73 to 2.77% for PO2. The OPTI 1 is concluded to provide canine blood gas analysis with an accuracy that is comparable with that of conventional benchtop blood gas analyzers.

Acid-Base Imbalance↗
PubMedDate not supplied

A case of infectious pseudoaneurysm of the abdominal aorta associated with infectious spondylitis due to Klebsiella pneumoniae.

A 67-year-old woman with pneumonia and diabetes mellitus was admitted with the complaints of abdominal and back pain. Sputum culture was positive for Klebsiella pneumoniae. Computed tomographic scanning (CT) of the abdomen and spinal radiograph of the lumber column revealed a paraventebral space-occupying lesion, abdominal aortic aneurysm and destructive change of L3 and L4. Pseudoaneurysm of the abdominal aorta associated with infectious spondylitis with paravertebral abscess was suspected and confirmed by aortography. Klebsiella pneumoniae was cultured from the abscess. The patient's condition improved rapidly after drainage of the abscess and administration of LMOX and gentamicin. Infectious pseudoaneurysm of the abdominal aorta associated with infectious spondylitis has rarely been reported. These two in combination due to Klebsiella pneumoniae has not been reported to our knowledge. The pathologic changes were found easily by CT scan. When infectious aneurysm or infectious spondylitis is diagnosed alone, possible combination of these diseases should be kept in mind.

Aged↗
PubMedDate not supplied

Antitumour effect of interferon combined with hyperthermia against experimental brain tumour.

Antiproliferative activity of recombinant murine interferon-beta (Rec-MuIFN-beta) combined with hyperthermia against Rous sarcoma virus-induced mouse malignant glioma (RSV glioma) was investigated both in vitro and in vivo. In vitro, the antiproliferative activity of Rec-MuIFN-beta was enhanced by incubation at elevated temperatures (40 degrees and 43 degrees C). In vivo, combined therapy of Rec-MuIFN-beta treatment and local tumour hyperthermia (43 degrees C) exerted a greater antitumour effect against transplanted RSV glioma in C3H/He mice than either treatment alone, especially when Rec-MuIFN-beta was administered intratumourally. Subsequently, in order to probe the mechanism of enhanced antiproliferative activity, the production of prostaglandin E2 (PGE2) and 2', 5'-oligoadenylate synthetase (2-5A synthetase) in the culture medium of RSV glioma cells was measured. Rec-MuIFN-beta treatment resulted in a significantly greater PGE2 and 2-5A synthetase production at 43 degrees C than at 37 degrees C.

2',5'-Oligoadenylate Synthetase↗
PubMedDate not supplied

Auditory brainstem response during systemic hyperthermia.

The relationship between the brain temperature and the latency of ABR was evaluated in a dog model of systemic hyperthermia induced by heating of the blood during extracorporeal circulation. The latency of ABR was shortened and the amplitude was reduced with the elevation of brain temperature. The shortening of the latency was more notable in wave 4 than in wave 1, and this is considered to have been due to greater changes in the conduction velocity in the central nervous system than in peripheral nerves. The latency of ABR, from which the brain temperature can be estimated, is considered to be clinically useful as an index of brain temperature during systemic hyperthermia.

Animals↗
PubMedDate not supplied

Effects of antineoplastic agents and hyperthermia on cytotoxicity toward chronically hypoxic glioma cells.

The effects of hyperthermia and antineoplastic agents on the cytotoxicity to normally oxygenated and chronically hypoxic glioma cells were investigated in vitro. Exposure to temperatures above 43.0 degrees C was less cytotoxic to hypoxic cells which predominantly accumulated in the G0/G1 phase fraction. On the other hand, mitomycin C (MMC) and adriamycin (ADM) were preferentially cytotoxic to hypoxic cells not only at 37 degrees C but also at elevated temperatures (42 degrees C and 43 degrees C). These two agents showed marked synergistic effects with hyperthermia under both oxygenated and hypoxic conditions. In contrast, bleomycin (BLM), cis-diamminedichloroplatinum(II) (CDDP), and vincristine (VCR) were preferentially cytotoxic to oxygenated cells at both 37 degrees C and elevated temperatures. CDDP showed cytotoxic synergism with hyperthermia that appeared to be oxygen-dependent. A nitrosourea derivative, 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU), showed no major preferential toxicity under either oxygenated or hypoxic conditions. This study suggests that hyperthermia in combination with MMC or ADM would have a greater cytotoxic effect on hypoxic cell subpopulations of malignant gliomas.

Antineoplastic Agents↗
PubMedDate not supplied

Drug delivery to the brain using thermosensitive liposome and local hyperthermia.

We investigated the possibilities of drug delivery to the brain using thermosensitive liposomes and hyperthermia. Thermosensitive liposomes are small vesicles containing some drugs, which are designed to release the drugs in response to hyperthermia. The first experiment consisted of four groups: (1) received free Cisplatin: cis-diamminedichloroplatinum (CDDP); (2) received free CDDP and above 41 degrees C local brain heating for 30 min; (3) received liposomes containing CDDP (CDDP-liposome); and (4) received CDDP-liposome and above 41 degrees C local brain heating for 30 min. Brain CDDP levels were significantly higher in (4), while those on the other groups were undetectable. In the second experiment, we studied the distribution of Evans blue (Eb) in the artificially heated region of mongrel dogs' brain. One group received free Eb and the other group received liposomes containing Eb (Eb-liposome). While the extravasation of free Eb was localized in regions heated > 44 degrees C, that of Eb-liposome was extended up to the regions heated at 41 degrees C. We concluded that the use of thermosensitive liposomes and hyperthermia not only contributes to the brain tumour killing as direct thermal killing does but also helps to increase the concentration of chemotherapeutic drugs into the tumour invaded zones with mild local hyperthermia of 41 degrees C.

Animals↗
PubMedDate not supplied

Hyperthermic sensitization by hematoporphyrin on glioma cells.

This study investigated: (1) the effect of Hp as a hyperthermic sensitizer on glioma cells; and (2) the possible mechanism of hyperthermic sensitization by Hp using an exogenous scavenger specific to a particular reactive oxygen species. Hp at nontoxic doses at 37 degrees C significantly enhanced thermal cell damage at 41.5 degrees C and above in a dose-dependent manner. Thermal cell damage enhancement by HP was effectively suppressed by the addition of beta-carotene, a singlet oxygen scavenger, or SOD, a superoxide scavenger, but not by the addition of mannitol or catalase. These results support the following hypothesis: The generation of superoxide is increased in cells treated with Hp in combination with hyperthermia. Thermal cell damage enhancement by Hp is probably mediated by singlet oxygen generated via superoxide in an alternative pathway different from that of photosensitization. Hp has potential as a hyperthermic sensitizer because of the following advantages: (1) its dose-dependent enhancement of thermal cell damage; and (2) the lack of toxicity at physiological temperature at doses of Hp required for hyperthermic sensitization of tumour cells.

Brain Neoplasms↗
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Antiproliferative effects of small fruit juices on several cancer cell lines.

Juices prepared from small fruits, mainly growing in the northern part of Japan, were studied in an attempt to explore the feasibility of an assay that screens cytotoxic properties. Screening of 43 small fruit juices indicated that Actinidia polygama Maxim., Rosa rugosa Thunb., Vaccinium smallii A. Gray and Sorbus sambucifolia Roem, strongly inhibited the proliferation of all cancer cell lines examined and yet these juices were substantially less cytotoxic toward normal human cell lines.

Beverages↗
PubMedDate not supplied

Primary intracranial solitary leptomeningeal glioma: a report of 3 cases.

Primary intracranial solitary leptomeningeal gliomas are exceedingly rare. We, therefore, performed a detailed clinical, radiological and pathological analysis to better characterize these tumors in 3 patients (33- and 72-year-old men and a 72-year-old woman). Two of the tumors were located in the frontal region and 1 in the temporal region. Magnetic resonance imaging revealed a well circumscribed large lesion (maximal diameter 4 - 6 cm) with peritumoral edema, mixed low- and isosignal intensity on T1-weighted images, hypersignal intensity on T2-weighted images and non-homogeneous contrast enhancement. External carotid angiography demonstrated a vascular supply to these tumors via branches of the middle meningeal artery. Gross total resection was achieved in all patients. The pathological diagnosis was glioblastoma in 2 patients and oligodendroglioma in 1. The MIB-1 nuclear labeling index ranged from 11.8% - 23.6% (mean 18.2%). Local tumor recurrence was documented in 2 patients after 8 and 11 months, respectively. The other patient with glioblastoma developed a metastasis to the femur 39 months after craniotomy. A definitive diagnosis can be made by careful radiological assessment and histopathological examination.

Adult↗
PubMedDate not supplied

Saccular aneurysm at the basilar artery fenestration.

The authors describe a 19-year-old patient who was presented with a subarachnoid hemorrhage and was found to have a saccular aneurysm arising at the proximal end of the fenestration of the basilar artery. Previously reported cases are reviewed. Stereoscopic magnification angiography facilitated the analysis of the three-dimensional-anatomical relationship between the aneurysm and its fenestrated parent artery.

Adult↗
PubMedDate not supplied

A case of cerebral air embolism predominant in the left cerebral hemisphere following subclavian catheterization.

We report a case of cerebral air embolism caused by right subclavian vein catheterization. A large amount of air was seen only over the left cerebral hemisphere on computed tomographic (CT) scans. Although neurological deficit was observed bilaterally at the onset, the degree of ischemic brain damage was far greater in the left cerebral hemisphere than in the right. This unusual left-sided predominancy of cerebral air embolism was presumably due to the tortuosity of the ascending aorta.

Aged↗
PubMedDate not supplied

Determination of ploidy in Cryptococcus neoformans by flow cytometry.

We determined the ploidy of Cryptococcus neoformans (28 strains) isolated from patients and nature. The cellular DNA content of these strains, which stained with propidium iodide in comparison to that of two authentic haploid strains, was determined by flow cytometry. All the strains exhibited diphasic histograms. In case of the authentic haploid strains, the first peak was centred around channel 9, and the second peak around channel 18. Most strains exhibited this type of histogram. Some strains exhibited another type of histogram: the first peak was centred around channel 18, and the second one around channel 35. In flow cytometry, the channel number is correlated with the intensity of fluorescence, namely, in proportion to the channel number the DNA content in the cells increases. The cellular DNA content of the second type of histograms showed twice that of the authentic haploid strains, and thus, five of 28 isolates were concluded to be diploid, and the others haploid.

Cryptococcosis↗
PubMedDate not supplied

Histopathological and electron microscopical studies on experimental Penicillium marneffei infection in mice.

Experimental Penicillium marneffei infection in mice was investigated histopathologically and by electron microscopy. Viable conidia (5 x 10(6) cells) of P. marneffei were inoculated into each mouse of group A (BALB/c mice) and group B (BALB/c-nu/nu-SIc mice) through the tail vein. All the mice were sacrificed at intervals and the livers were examined. In group A, the conidia were phagocytosed by Kupffer cells soon after inoculation, and proliferated by fission in the cytoplasm. Marked proliferation of yeast cells was observed 7 and 14 days after inoculation. With proliferation of the fungus, the number of lysosomes in Kupffer cells increased, and numerous granulomas were formed in the liver. These granulomas consisted mainly of macrophages with yeast cells, together with a few polymorphonuclear leukocytes, lymphocytes and giant cells. From 28 days on yeast cells were gradually cleared from the granulomas, and 56 days after inoculation almost all the granulomas disappeared. In group B, at an early stage of infection, similar pathological changes to those seen in mice of group A were observed. However, as the infection progressed, the number of granulomas continued to increase and yeast cells continued to proliferate although lymphocytes did not infiltrate these granulomas. With proliferation of yeast cells the liver tissue was replaced with both yeast cells engulfed by macrophages and extracellular yeasts, and dissemination occurred.

Animals↗