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H Maezawa

Publications and source records attributed to H Maezawa.

At least 19 recordsLinked to original sources
PubMed1995

[Spinal multiple sclerosis mimicking a spinal cord tumor: a case report].

Since the advent of magnetic resonance imaging (MRI), to visualize lesions of multiple sclerosis has become easy to do. However, in some cases with primary spinal cord multiple sclerosis, it is not always easy to obtain a diagnosis in the first instance. We reported a case of primary spinal multiple sclerosis diagnosed through histological examination of a surgical specimen taken by an open biopsy. A 35-year-old woman was admitted with complaints of two-months duration of progressive weakness and sensory disturbance in the legs and buttocks. On radiological examinations including metrizamide CT myelography and MRI, enlargement of the conus medullaris was the only positive finding. Respective to her clinical course, intramedullary spinal cord tumor could not be ruled out, so an open biopsy was performed. Histological examination revealed that the cord lesion was acute demyelination with perivascular inflammation. Her neurological signs were almost completely cured with administration of corticosteroid, though new brainstem signs took place two months later and then a concrete diagnosis of her having multiple sclerosis was finally achieved. Since preoperative examinations can not differentiate spinal cord tumor from any other intramedullary cord lesions such as demyelinating foci of multiple sclerosis, surgical intervention would be approved in such atypical primary spinal cord multiple sclerosis.

Adult↗
PubMed1994

Properties of single potassium channels in guinea pig hepatocytes.

The patch-clamp technique of cell-attached and inside-out configurations was used to study the single potassium channels in isolated guinea pig hepatocytes. The single potassium channels in isolated guinea pig hepatocytes were recorded at different K+ concentrations. A linear single-channel current-voltage relationship was obtained at the voltage range of -80 to -20 mV with slope conductance of 70 +/- 6 pS (n = 10). Under symmetrical high K+ concentration of 148 mM in the cell-attached patch membrane, the I-V curve exhibited a mild inward rectification at potentials positive to + 20 mV. The values of reversal potential was +5 +/- 2 mV (n = 10). When the external potassium concentration ([K+]o) was decreased to 74 mM and 20 mM, the slope conductance was decreased to 48 +/- 2 pS (n = 4) and 24 +/- 3 pS (n = 3), respectively. The reversal potential was changed by 58 mV for a tenfold change in [K+]o, indicating that this channel was highly selective for K+. Open probabilities (Po) of the channel were 73-93% without apparent voltage dependence. The distributions of open time of the channels were fitted to two exponentials, while those of closed time were fitted to three exponentials, exhibiting no voltage dependence. The success rate of K+ channel activity to be recorded was 28% at room temperature, and there were no increases in the success rate nor in the channel opening probabilities at a temperature of 34-36 degrees C. Po in inside-out patches was not changed by application of 1 microM Ca2+ nor 1 mM Mg2+ to the internal side of patch membranes. It is concluded that a novel type of the K+ channels in guinea pig hepatocytes had different properties of slope conductance, channel kinetics, and sensitivity to [Ca2+]i, from those in other species.

Animals↗
PubMed1993

Uracil-DNA glycosylase produces excess lethal damage induced by an Auger cascade in BrdU-labelled bacteriophage T1.

T1 phages with and without 5-bromo-2'-deoxyuridine (BrdU) labelling were irradiated in solids with monochromatic X-rays at 12.40 and 13.51 keV, below and just above the K-absorption edge of bromine (13.47 keV) in vacuum and wet states. Irradiated phages were assayed on uracil-DNA glycosylase (Udg) deficient (ung-1) and sufficient (ung+) host strains of Escherichia coli, in order to investigate the nature of the lethal damage induced by Auger cascade following X-ray absorption at the K-shell of bromine as a key atom. The results were: (1) An Auger-specific enhancement (1.15) was observed only when BrdU-labelled phages were irradiated in the wet state and assayed on ung+ host cells. (2) A Udg-specific enhancement was observed only for BrdU-labelled phages, not for unlabelled phages. (3) The sensitivities of BrdU-unlabelled phages were almost the same, despite the irradiation states and strains of the host cell, indicating that this sensitivity was a common fraction of the sensitivity under all conditions. (4) The lethal damage for the T1 phage was categorized into four fractions according to the sensitivities under different conditions: the general fraction was defined as being the sensitivity of unlabelled phages (G-fraction); BrdU-specific, but unrecognizable by Udg (B-fraction); Udg specific, but not Auger-specific (U-fraction); and Auger-specific (A-fraction). (5) Although the so-called indirect action of water radicals increased only the G-fraction by about three-fold, the B- and U-fractions were not affected by any change in the irradiation states, thus indicating that these two fractions were caused by the so-called direct action.

Affinity Labels↗
PubMed1993

[Treatment of severe pneumonia due to methicillin-resistant Staphylococcus aureus (MRSA) and Candida krusei with granulocyte colony-stimulating factor (G-CSF): a case report].

A 24-year-old male with chronic renal failure on Continuous Ambulatory Peritoneal Dialysis (CAPD) complained of cough and dyspnea. Chest X-ray film showed a pneumonia shadow and MRSA and Candida krusei were detected in the sputum. Pneumonia improved with vancomycin and fluconazole. Treatment with methylprednisolone was needed for retinodialysis. After this treatment, pneumonia deteriorated. Pneumonia did not improve with vancomycin and anti-fungal agents. This severe pneumonia was improved with a combination therapy of vancomycin, miconazole and G-CSF. A combination therapy of antibiotics and G-CSF is considered to be effective for severe pneumonia.

Adult↗
PubMed1993

[The local relapse of prostatic cancer and initial local treatment].

We treated fifty cases of prostatic cancer that had no distant metastasis and no other primary cancers between October 1983 and September 1990. Our initial treatment for clinical stages A2, B1, B2 included radical prostatectomy, pelvic lymphadenectomy, and bilateral orchiectomy. Staging lymphadenectomy with bilateral orchiectomy was applied to patients with clinical stage C tumor, and if there was no lymph node metastasis, external beam radiation therapy for the prostate was performed. Patients who did not consent to major surgeries or had poor general status or had clinical stage D1 tumor underwent bilateral orchiectomy. Mean observation period was forty-one months. Eleven cases relapsed. Of the eleven cases, ten had local relapse at the diagnosis of relapse (two of them had distant metastasis simultaneously, six of them had distant metastasis later, and two of them had no distant metastasis in the observation period). All these ten cases had no underwent the initial local treatment. The remainder who had underwent radical prostatectomy relapsed with distant metastasis alone. This study suggests that the local relapse tends to precede distant metastasis as the mate of relapse of prostatic cancer excluding stage D2. There is a possibility that initial local treatment is useful improving the prognosis of the patients for clinical stage A2-D1 prostatic cancer.

Adenocarcinoma↗
PubMed1993

Synergistic effects of hyperthermia and intratumorous injection of anti-cancer drugs.

In an attempt to improve the combined effects of hyperthermia and anti-cancer drugs, an intratumorous (i.t.) injection of the drugs was performed and its effect compared with that obtained by intraperitoneal (i.p.) injection. Using Lewis lung carcinoma growing in the legs of BDF1 mice, weakly toxic drug derivatives, Aclarubicin (ACR), a new platinum complex (DWA2114R), or Peplomycin (PEP) were injected either into the center of the tumors, or intraperitoneally, before or after usual hyperthemia in a 43.5-43.7 degrees C water bath for 45 min. The effects on tumor growth delay and the number of lung metastases were assessed, and the enhancement ratios (ERs) due to the combination were calculated. Tumor growth inhibition by i.t. injection was enhanced additively with ACR (ER; 1.2) and synergistically with DWA2114R (ER; 3.49) and PEP (ER; 2.4) plus hyperthermia. Hyperthermia after i.t. injections of DWA2114R (ER; 3.4) was more effective than either i.t. or i.p. injections after hyperthermia (ER; 2.4). Lung metastases were also inhibited significantly by the combination of hyperthermia and drugs, except when emulsified PEP was injected three times. It was concluded that the i.t. injection of DWA2114R was of value when used in combination with hyperthermia.

Aclarubicin↗
PubMed1992

Radiosensitivity of mouse skin epithelial cell line established in serum-free culture: an alternative to animal use.

A cultured line of murine skin epithelial cells was established to investigate the potential use of cultured cells as an alternative to animal use in radiation research. C3Hf/Sed newborn mouse skin cells have been successfully cultured in serum- and Ca(2+)-free medium with no terminal differentiation to keratinized cells. Presently, more than 25 passages have passed with no loss of stem cell capability. The radiosensitivity and repair of sublethal and potentially lethal radiation damages were investigated in this epithelial cell line. The population cell doubling time was 25 +/- 2.9 hr at 37 degrees C. The clonal growth of epithelial cells after irradiation was performed in the serum-free medium in the presence of lethally irradiated skin fibroblasts. Single dose survival curves of exponentially growing epithelial cells were investigated from the seventh to the twenty-third passages, and no significant changes in radiosensitivity and doubling time were found. The confluent epithelial cells also showed an identical sensitivity to radiation. The alpha/beta ratios of survival curves fitted by the linear quadratic model were 6.1 +/- 1.0 and 5.9 +/- 1.3 Gy for cells in exponential and confluent phases, respectively. The survival curve of epithelial cells left in confluence for 8 hr after irradiation showed a smaller beta value than that of cells plated immediately after irradiation with a resultant alpha/beta ratio of 9.5 +/- 3.8 Gy. This alpha/beta ratio was identical to those found in many animal experiments, suggesting a potential use of this cell line as an alternative to animal use. The magnitude of repair of sublethal damage following 6 Gy was greater than that following 3.9 Gy. Survival curves were also obtained following twice-a-day irradiations with no sign of rapid repopulation. These results are discussed by comparing with published in vivo and in vitro data.

Animal Testing Alternatives↗
PubMed1992

Iron(II) sulphate (Fricke solution) oxidation yields for 8.9 and 13.6 keV X-rays from synchrotron radiation.

The oxidation yields (G) for 8.86 and 13.55 keV X-rays produced by synchrotron radiation were measured using an iron(II) sulphate (Fricke) solution. Monoenergetic X-rays were produced using a silicon crystal monochromator. The X-rays were absorbed in 0.4 M sulphuric acid-iron(II) sulphate solution and FeIII ion yields were measured and corrected for escape fractions resulting from scattering using Monte Carlo calculations. Doses in the solution were determined using a thin window, parallel plate chamber calibrated against a primary standard free-air chamber at the Electrotechnical Laboratory (Osaka, Japan). Yields (G) of 1.50 +/- 0.06 and 1.43 +/- 0.06 mumol J-1 were obtained for 8.86 and 13.55 keV X-rays respectively.

Oxidation-Reduction↗
PubMed1992

Ca(2+)-activated K+ channel is present in guinea-pig but lacking in rat hepatocytes.

The mechanisms of norepinephrine-induced membrane responses in isolated hepatocytes from guinea-pigs and rats were compared using the suction-pipette, patch-clamp method, and intracellular Ca2+ concentration ([Ca2+]i) was measured using the Ca2+ fluorescent dye, Quin 2. The resting membrane potentials of isolated guinea-pig hepatocytes were -50 +/- 1 mV (mean +/- SD; n = 38), which is similar to that previously reported in rat hepatocytes by Sawanobori et al. (J Cell Physiol 139: 580-585, 1989). In guinea-pig hepatocytes, norepinephrine (6 microM) caused a membrane hyperpolarization, and norepinephrine (6 microM) or Ca(2+)-ionophore (A23187) (0.4 microM) caused a corresponding outward current. The sensitive current produced by norepinephrine and Ca(2+)-ionophore reversed its polarity at -74 +/- 9 mV (n = 7). The single channel recorded by cell-attached patch and inside-out patch had mean conductance of around 20 + 1 pS and was activated by 1 microM [Ca2+]i. On the other hand, neither norepinephrine (6-20 microM) nor Ca(2+)-ionophore (A 23187) (0.4 microM) caused any change in membrane potential and current in rat hepatocytes, whereas norepinephrine increased [Ca2+]i both in rat and guinea-pig hepatocytes to a similar degree. In the single-channel recording, we recorded single channels that had a mean conductance of 109.8 +/- 17.7 pS different from around 20 pS in guinea-pig. In inside-out patches, increased Ca2+ concentration from 10(-6) to 10(-3) M at the intracellular face of the membrane did not modify the single channel of rat hepatocytes. These results indicate that increased [Ca2+]i activates this channel in guinea-pigs, but that the channel activated by increased [Ca2+]i is lacking in rat hepatocytes membrane. Therefore, different mechanism operates in different species of liver cells to keep the constant state.

Animals↗
PubMed1991

Thallium-201 stress scintigraphy in Takayasu arteritis.

Thirty-eight women with Takayasu arteritis were studied using thallium-201 stress myocardial scintigraphy to assess the prevalence and pathophysiology of the perfusion abnormality. Twenty (53%) had abnormal scintigraphic findings (group A). Abnormal scans were divided into 3 groups: permanent defects in 6, reversible defects in 7 and slow washout in 7. The remaining 18 patients had normal scintigrams (group N). Group A had a tendency to be older and to have a high prevalence of complicated significant aortic regurgitation. Interventricular thickness plus left ventricular posterior wall thickness (26 +/- 7 vs 17 +/- 2 mm, p less than 0.01) and left ventricular mass (267 +/- 121 vs 133 +/- 39 g, p less than 0.01) were all greater in group A on echocardiography. The mean value of the central aortic pressure in systole was 170 +/- 15 mm Hg in the 7 catheterized patients in group A. Coronary ostial stenoses were present in 2 group A patients who showed reversible defects on scintigrams. These data indicate that the abnormal perfusion detected by imaging in patients with Takayasu arteritis was responsible for a decrease in coronary reserve or myocardial damage, or both, due to long-standing systemic hypertension or aortic regurgitation. Coronary artery disease should be considered if a reversible defect is present.

Adult↗
PubMed1991

Organic anion transport study in mutant rats with autosomal recessive conjugated hyperbilirubinemia.

The EHBR is a mutant rat strain with congenital conjugated hyperbilirubinemia bred from a Sprague-Dawley rat. Transport of conjugated bilirubin, indocyanine green, and tetrabromosulfophtalein from liver to bile is severely impaired in these rats. Serum bilirubin amounts to 6.0 +/- 0.05 mg/dl (n = 4) in adult rats, with 97% conjugates. The bile flow is reduced to about 65% of the control group, whereas total bile acid in 10-min bile samples is similar. Liver histology of 10 week-old rats revealed neither intracellular pigmentation nor architectural abnormalities.

Animals↗
PubMed1991

Serum ketone response to glucagon as a marker of insulin dependency in diabetics.

The serum ketone response to glucagon was measured in 10 patients with IDDM and 37 with NIDDM. In both groups, serum 3-hydroxybutyrate increased significantly after intravenous injection of 1 mg glucagon. The difference between the serum level of 3-hydroxybutyrate at 30 min and basal level [delta 3-OHBA(30')] was 133 +/- 25 mumol/l in the patients with IDDM, 13 +/- 8 mumol/l in those with NIDDM treated by diet alone or with oral hypoglycemic agents and 23 +/- 13 mumol/l in those with NIDDM treated with insulin. The delta 3-OHBA(30') was significantly greater in IDDM patients than in both groups of NIDDM patients (P less than 0.001). The delta 3-OHBA(30') was greater than 87 mumol/l in eighty percent of IDDM patients, but smaller than 87 mumol/l in both groups of NIDDM patients. The delta 3-OHBA(30') was correlated with the difference between the plasma level of C-peptide at 6 min and basal level [delta CPR(6')] (r = -0.540, P less than 0.001). The delta 3-OHBA(30') was not correlated with fasting plasma levels of glucose, fructosamine or hemoglobin A1c. These observations show that measurement of the serum ketone response to glucagon is a useful marker of insulin dependency. In order to determine insulin dependency, the simultaneous measurement of concentrations of ketones and C-peptide is indicated during the glucagon stimulation test.

3-Hydroxybutyric Acid↗
PubMed1991

Effects of K-shell X-ray absorption of intracellular phosphorus on yeast cells.

The effects of K-shell absorption of phosphorus atoms on yeast cells were investigated using synchrotron X-rays that were tuned to the resonance absorption peak (2153 eV). Three types of cellular effect (cell inactivation, induction of gene conversion at the trp-5 locus, and cell membrane impairment (changes in the permeability] were measured. It was demonstrated that the enhancement factor was 1.4 at the resonance peak regarding both lethality and the induction of gene conversion in reference of off-peak irradiation (2146 and 2160 eV). No difference was found between the two off-peak irradiation energies. No cell membrane impairment was detected, irrespective of the X-ray photon energies employed within the fluence range tested. These results strongly suggest that K-shell X-ray absorption in the resonance mode by cellular phosphorus atoms causes significantly more cellular effects than the off-resonance mode of absorption, probably via some specific changes induced in the phosphates of the DNA strand. Calculations using the number of phosphorus atoms in a defined size of the trp locus (2127 base pairs) on the DNA and the absorption cross-section of the resonance mode of phosphorus showed that gene conversion is inducible at a rate of 0.13 per X-ray photon absorption per locus. These results are discussed regarding the modes of K-shell photoabsorption.

Absorption↗
PubMed1991

Biological effects of Auger processes of bromine on yeast cells induced by monochromatic synchrotron X-rays.

The biological effects of inner-shell ionization in bromine atoms incorporated into DNA in the form of bromodeoxyuridine monophosphate (BrdUMP), induced by monochromatized synchrotron X-rays, were studied using a deoxythymidine monophosphate (dTMP)-permeable mutant of yeast, Saccharomyces cerevisiae. The BrdUMP-incorporated yeast cells were irradiated with monochromatic X-rays of 13.51 or 13.45 keV, between which the bromine K-absorption edge (13.47 keV) is located. The cells were 1.07 times more sensitive to irradiation by 13.51 keV X-rays than at 13.45 keV, while dTMP-incorporated cells did not show any difference in sensitivity. In the presence of a radioprotector during irradiation, BrdUMP-incorporated cells showed a larger enhancement (1.20). These enhancements observed in the bromine-incorporated cells cannot be explained only by an increase of the absorbed dose due to a substitution of CH3 group of thymine by bromine. It may be concluded that a major part of the enhancement was caused by inner-shell photoionization, followed by an Auger cascade of the bromine in the DNA. The quantum yield of lethality caused by the photoabsorption of bromine K-shell is not affected by the presence of cysteamine, suggesting the biological enhancement by the Auger processes may not be influenced by chemical protection.

Bromodeoxyuridine↗
PubMed1991

Enhanced killing effect on 5-bromodeoxyuridine labelled bacteriophage T1 by monoenergetic synchrotron X-ray at the energy of bromine K-shell absorption edge.

5-Bromo-2'-deoxyuridine labelled bacteriophage T1 was irradiated with monoenergetic X-rays obtained from synchroton radiation with the energies at 13.51 keV and 12.40 keV, just above and below the K-shell absorption edge (13.41 keV) of bromine, respectively. Phage samples were irradiated under three conditions, wet N2 gas, dry N2 gas and in vacuum, with water contents (g H2O/g sample) of 60, 2.6 and 0%. At 12.40 keV the D0 in kGy were 1.1 ("wet"), 1.9 ("dry") and 2.5 ("vacuum") for the Br-labelled phages and 1.6 ("wet"), 2.4 ("dry") and 6.2 ("vacuum") for unlabelled phages. The results clearly demonstrated that the X-ray sensitivities decreased with decrease in water contents. Br-enhancement ratios, ER = D0 (unlabelled)/D0 (Br-labelled), varied from 1.4 ("wet", 12.40 keV) to 2.5 ("vacuum", 13.51 keV). Auger enhancements which were defined by energy-dependent enhancement factor, Fen = [ER(13.51 keV)-ER(12.40 keV)]/ER(12.40 keV), were 0.09 +/- 0.09, 0.29 +/- 0.07 and 0.02 +/- 0.03 under "wet", "dry" and "vacuum" conditions, respectively. The change in Auger enhancement under "dry" condition in comparison with "wet" condition could be explained due to less of water. However the Auger enhancement decreased sharply under "vacuum" condition as the water content was zero. The reason for the sharp decrease in Auger enhancement under "vacuum" condition is difficult to understand. A possible explanation is discussed in the text.

Bromodeoxyuridine↗
PubMed1991

Increased thrombomodulin values in plasma of diabetic men with microangiopathy.

To study the significance of plasma thrombomodulin (TM) values in diabetes mellitus, we determined plasma TM in 34 patients with non-insulin-dependent diabetes mellitus (NIDDM) men, mean age 54 (SE 2) years. Plasma TM was determined by an enzyme immunoassay with anti-TM monoclonal antibodies. The plasma TM values were significantly greater in NIDDM patients with nephropathy than in patients without nephropathy (P less than 0.001). Also, a significant positive correlation was noted between the concentration of plasma TM and serum creatinine (r = 0.55, P less than 0.001). The plasma TM values of the patients with retinopathy were significantly greater than the values of those without it (P less than 0.002). Furthermore, we noted a significant positive correlation (r = 0.78, P less than 0.001) between plasma TM and the severity of diabetic retinopathy as graded by Scott's classification. These results suggest a close relationship between TM and diabetic microangiopathy.

Adult↗