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Biomedical subjects

Y Midorikawa

Publications and source records attributed to Y Midorikawa.

At least 37 records · Page 2Linked to original sources
PubMed1996

The neutrophil as an information transmitter in tumor inhibition by a streptococcal biological response modifier, OK-432.

Effective treatment of a rat transplanted ascites tumor by i.p. injection of a streptococcal biological response modifier, OK-432, was abrogated by selective in vivo depletion of neutrophils by a monoclonal antibody, RP-3. The mechanisms by which neutrophils participate in the therapeutic action of OK-432 were studied with Winn's assay using peritoneal exudate cells periodically obtained from rats i.p. injected with this biological response modifier. Intraperitoneal resident macrophages were first activated with OK-432, and within 3 h, tumor-inhibitory activity had moved to the early exuded neutrophils. However, 6 h after injection, exuded macrophages were the only cells involved in tumor inhibition. Considered together with other findings, it is likely that, in this system, neutrophils may transmit information from resident macrophages to exuded inflammatory macrophages in a series of responses induced by i.p. injection of OK-432.

Animals↗
PubMed1996

Diarrheal and environmental isolates of Aeromonas spp. produce a toxin similar to Shiga-like toxin 1.

Diarrheal and environmental isolates of 39 strains of Aeromonas spp. were studied for detection of virulence factors. Although these 39 strains did not produce either heat-labile or heat-stable enterotoxins, culture filtrates of 31 strains produced cytopathic effects on Vero cells. Among these, culture filtrates of three strains of Aeromonas hydrophila and one strain of Aeromonas caviae could be neutralized by Escherichia coli O157:H7 Shiga-like toxin 1 antiserum. A single band of plasmid DNA of 2.14 kbp was isolated from these strains of Aeromonas spp. and E. coli O157:H7, which could be amplified by the polymerase chain reaction (PCR), employing oligonucleotide primers from the Shiga-like toxin 1 (SLT1) gene of E. coli O157:H7. E. coli HB 101 cells when transformed with the same plasmid showed cytopathic effects on Vero cells, which indicates that the SLT 1 homolog gene(s) of Aeromonas spp. is plasmid encoded. These results suggest that Aeromonas spp. may also produce Shiga-like toxin 1, or at least a cytotoxin with some homology with the Shiga-like toxin 1 of E. coli O157:H7.

Aeromonas↗
PubMed1996

Purification and characterization of purine nucleoside phosphorylase and pyrimidine nucleoside phosphorylase from Bacillus stearothermophilus TH 6-2.

The purine nucleoside phosphorylase (Pu-NPase) and the pyrimidine nucleoside phosphorylase (Py-NPase) have been purified from Bacillus stearothermophilus TH 6-2. The Pu-NPase is a trimer of 30-kDa subunits and the Py-NPase is a dimer of 46-kDa subunits. The isoelectric points of Pu-NPase and Py-NPase were pH 4.3 and 4.6, respectively. The Pu-NPase could catalyze the phosphorolysis of inosine and guanosine, but not adenosine. the Py-NPase could phosphorolyze both uridine and thymidine.

Amino Acid Sequence↗
PubMed1996

Molecular cloning and expression of the pyrimidine nucleoside phosphorylase gene from Bacillus stearothermophilus TH 6-2.

The pyrimidine nucleoside phosphorylase (Py-NPase) of Bacillus stearothermophilus TH 6-2 is a dimer of 46-kDa subunits and catalyzes the reversible phosphorolysis of uridine and thymidine. The gene encoding this pyrimidine nucleoside phosphorylase (pyn gene) has been cloned and sequenced from B. stearothermophilus TH 6-2. The pyn gene corresponded to an open reading frame of 1299 nucleotides that translates into a putative 433 amino acid protein with a molecular weight of 46,271. The deduced amino terminal sequence of Py-NPase coincided with that previously found for the purified enzyme. The deduced amino acid sequence of Py-NPase shared significant similarity with those of human and Escherichia coli thymidine phosphorylases. The cloned pyn gene was overexpressed in E. coli cells to produce an active enzyme in large quantities that accounted for approximately 20% of the total protein.

Amino Acid Sequence↗
PubMed1996

[A case of volatile solvent psychosis accompanied with multiple neurological and psychological symptoms].

A case of psychosis accompanied with variable symptoms induced by chronic volatile solvent inhalation is reported in this study. The patient was a 27-year-old male who had abused volatile solvents for 15 years, and was sent to the hospital because of a tonic-clonic seizure. Severe psychomotor excitement was observed on the first day and the 7th day after admission. After 10 days of admission, we observed visual transformation and hyperthermia, which suggested acute toxic symptoms due to a volatile solvent. Furthermore, symptoms such as incoherence, delusions of persecution, and catalepsy were also observed in this case. There have been few reports of multiple neurological and mental symptoms appearing in cases of volatile solvent psychosis. Although we sometimes experience cases of solvent abuse with acute mental symptoms and recurrent excitement after sedation, such symptoms are not always observed because of flashback in the strict sense. Therefore, careful early treatment should be employed to prevent 'secondary excitement'.

Adult↗
PubMed1996

[Closing-in phenomena observed in patients with Alzheimer's disease--analysis of drawing behavior and eye movements].

'Closing-in' symptom is defined as a tendency to close-in on the model while performing constructive tasks. This unique symptom is one of the constructional apraxia often observed in Alzheimer's disease (AD), which is considered to be involved in visuospatial dysfunctions. However, little is known about the nature of the symptom and pathophysiology underlying the symptom. In this study, we examined drawing behavior, eye movements of AD (n = 19), multi-infarct dementia (n = 8) and age matched healthy subjects (n = 10). 1) In AD, contrary to age matched healthy subjects, the patients drew slowly with apparent difficulty and drawing behavior was disorganized. The copied figures were incomplete and often fragmented. The spatial relationships of the parts were lost each other during copying a Necker's cube. 2) The characteristic eye movements were observed in AD patients with apraxia, and closing-in symptom. These were consisted of gaze apraxia, and disorders of visual attention appeared similar to Bàlint's syndrome. 3) The eye movements of the AD patients with closing-in symptoms were classified into wandering of fixation, locking of fixation, and mixed types. The 'closing-in' symptoms in copied figures were classified into three types, overlap, adherent, and near types. Then, the wandering type was seen both in near and adherent types, whereas the fixation type was only found in the overlap type. 4) SPECTs showed reduced RI activities in the parieto-occipital and in the frontal regions of AD patients with apraxia and closing-in symptoms. Our results suggest that AD patients may have a difficulty to create abstract space from concrete space. This may also imply regression to a primitive undifferentiated stage where gnostic and practic behavior is not differentiated in terms of space appreciation.

Aged↗
PubMed1996

[Use of a laryngeal mask airway for anesthesia in a patient with bronchomalacia].

A 56-year-old woman with bronchomalacia underwent three consecutive operations for bronchoscopy, cautery YAG-laser, and the insertion of a stent under general anesthesia using a laryngeal mask airway (LMA). For the first operation, anesthesia was induced with ketamine 20 mg, diazepam 5 mg and pentazocine 20 mg. The patient was ventilated with N2O-O2-sevoflurane with a face mask. Then vecuronium 6 mg was administered intravenously and LMA was inserted blindly. Anesthesia was maintained with N2O-O2-sevoflurane during bronchoscopy. Immediately after the operation, the patient coughed and experienced dyspnea. The symptoms were alleviated using theophyllin, hydrocortisone and droperidol. For the second and third operations, anesthesia was induced with droperidol and fentanyl with N2O-O2. After administration of vecuronium, LMA was inserted. The patient was stable during the second and third operations compared with the first operation. It was concluded that LMA may be useful for anesthetic management of a patient with bronchomalacia.

Anesthesia, General↗
PubMed1996

[Biological characteristics of amyloid precursor protein and Alzheimer's disease].

Recent advances in Alzheimer's disease (AD) research were briefly reviewed. AD is the most common cause of progressive intellectual decline in the aged in the Western world and also in Japan. The AD-affected brain is characterized by numerous amyloid plaques, neurofibrillary tangles, and neuronal losses. The amyloid deposition is considered to be more important because it appears first, and is followed by NFTs. The amyloid is composed of amyloid beta peptide (Abeta), a 40 approximately 42 amino acid fragment of the large membrane protein, amyloid precursor protein (APP). Abeta is cleaved by the proteolytic enzymes, beta, and gamma secretase. Considerable effort has been directed to identify these enzymes, and to find the intracellular compartments where Abeta is generated. The lysosome, or related acidic compartment is one of the candidates. The N and C terminis of the Abeta is known to vary slightly. Biochemical and immunopathological studies implicate that Abeta42 is more important than Abeta40 in the pathogenesis of AD. On the other hand, many missense mutations in APP gene and other genes, e.g. S182, and STM 2 have been identified in familial AD. Neuropathologically, AD is regarded as cerebral Abeta amyloidosis. The AD amyloid is composed of many proteins other than Abeta, designated as amyloid associated proteins. These proteins may play important roles in amyloid formation, since Abeta itself is soluble. Transgenic mice and chloroquine myopathy rat are available as animal models for AD. Elucidation of the roles of these missense mutations, and amyloid associated proteins in the cascade of AD, may provide a breakthrough to therapeutics for AD.

Alzheimer Disease↗
PubMed1996

[Influence of nitric oxide on superoxide anion radical generation in vivo].

We studied the effect of NO on superoxide anion radical (O2-) generation using chemiluminescence method by examining influence of NO gas on superoxide radical generation in rat lung induced by paraquat (PQ) on CLA-phenyl hybrid paper filters. SD rats were allocated into four groups. Group 1 received i.v. injection of physiological saline as a control group; Group 2 received 70 mg x kg-1 of PQ i.v.; Group 3 received 50,000 unit x kg-1 of SOD i.v., 1, 2, and 3 hours after i.v. PQ administration. Group 4 inhaled 50 ppm NO gas after i.v. injection of PQ. Three hours after administration of each drug in respective group, the right lower lobe of the lung was removed and immediately immersed into liquid nitrogen and then was sliced in width of 20 microns at -20 degrees C using cryostat. The results were summarized as representing overall level of superoxide radicals in each lung sample. PQ increased O2- production by 48% in comparison with the control. However, SOD and NO gas decreased O2- production significantly approximately up to the control level. These results confirmed that NO depresses O2- production in vivo.

Administration, Inhalation↗
PubMed1996

[Relationship between SPECT and pathological alterations in Alzheimer's disease--a study of a case with left-hemisphere dominant lesions].

123I-IMP SPECT (SPECT) has been widely used in clinical neuropsychiatry for establishing the clinical diagnosis, and evaluating the course of the disease. However, little is known about the significance of alterations in SPECT. In this paper, we present comparative study between alterations in SPECT and neuropathological findings in the case of Alzheimer's disease (AD). The patient, a 59-year-old female, began to show memory disturbance and the left hemisphere disturbances, non-fluent aphasia, but right hemisphere disturbances, constructional apraxia, visuo-spatial dysfunctions were not notable at the early stage. The neuroimaging also revealed left-side dominant cerebral atrophy in MRI and left-side dominant hypoactive regions in SPECT (especially in parietal lobe). Memory disturbance and non-fluent aphasia gradually progressed after admission. Then, mirror phenomenon and Bálint's syndrome appeared at the age of 63 years. In the advanced stage, hypoactive regions in SPECT were expanded into temporal and frontal areas. The laterality observed at the early stage became unremarkable. The patient died from heart failure at 64 years. Pathological diagnosis was AD. Eleven ROI (region of interests) were determined on each hemisphere in transverse SPECT image. We calculated ROI% (each ROI count/ROI count at central cerebellum). Neuronal cell count (NCC) and amyloid beta protein deposited areas (BDA) were estimated using 3 serial sections stained with Nissl's method and immunostained for amyloid using monoclonal antibody raised against synthetic A beta, mcAb 90/12. Digitized images based on photographs were analyzed with NIH-image 1.45. NCC decreased in number in frontal, temporal, and parietal lobes. Significant asymmetrical reduction of NCC (lt. < rt.) was observed in orbital, superior temporal and angular gyri (p < 0.01). BDA in superior parietal lobule, superior temporal gyrus and superior, middle, inferior frontal gyri were larger than those in precentral gyrus and visual cortex. Asymmetry of BDA (lt. > rt.) was significant in middle temporal gyrus (p < 0.01). ROI% at the early stage was correlated with corresponding NCC (r = 0.49, p < 0.05) and BDA (r = -0.55, p < 0.01), but at the advanced stage was not significantly correlated with corresponding NCC (r = 0.26) and BDA (r = -0.20). It is evident that SPECT shows good correlation with clinical features and pathological alterations during the course of AD. Our observations imply that the changes in SPECT usually precede the appearance of the clinical symptoms. SPECT is very sensitive in detecting the functional decline in certain regions of the CNS. In the case of AD, the hypoactive regions in SPECT at the early stage may indicate functional decline of the neuronal cells, and at the advanced stage, these may indicate the degree of pathological changes, especially neuronal loss and amyloid beta protein deposition.

Alzheimer Disease↗
PubMed1996

Characterization of Aeromonas hydrophila: a comparative study of strains isolated from diarrheal feces and the environment.

Thirty-five strains of Aeromonas hydrophila isolated from feces of diarrheal patients and from the environments were collected from Thailand and Japan. The physiological, biochemical, and serological characteristics, antibiotic resistance patterns and cell surface-related properties were compared. The diarrheal and environmental isolates of A hydrophila were found to be remarkably consistent in general culture and biochemical characteristics, with the exception of the reaction to D-arabinose in which the diarrheal strains were positive and environmental strains were negative. The plasmid patterns and cell surface-related properties of the environmental and diarrheal isolates were different. All strains produced Vero cell cytotoxin, hemolysin and lecithinase at 37 degrees, 30 degrees and 15 degrees C. In contrast, 83% of the environmental strains produced these virulence factors even at 4 degrees C. All strains indicated almost uniform susceptibility to the 16 antibiotics tested. Variations were found in the plasmid profile, toxin production in relation to the differences of temperature and cell surface-related properties of the strains. These variations between the clinical and environmental isolates could have potential as epidemiological markers for the sources of strains.

Aeromonas hydrophila↗
PubMed1996

Bacterial diarrhea in Laos, a region where cholera was endemic.

There were cholera outbreaks in Lao PDR since 1993. Two provinces were epidemic areas of cholera in 1993. However the area of cholera occurrence increased to 7 provinces through 1994. Then a bacterial survey had done for the purpose of public health improvement. EPEC was markedly isolated from the hospital in Vientiane. In apparent infection of Salmonella and non-01 Vibrio cholerae with soldiers stationed in the island in Mekong River belong to Vientiane were pointed out. The outbreak of diarrhea in suburban village of Vientiane, the diarrhea was not due to cholera but due to Shigella dysenteriae and Aeromonas sobria. As far as results in the capital city Vientiane and the Vientiane province go, it could say that there was no record and isolation of V. cholerae or non-01 V. cholerae 0139 in this study. On the contrary, Vibrio cholerae 01 serotype Eltor Ogawa was isolated although the community declared the end of the cholera outbreak. This study pointed out the importance of establishing sanitary conditions and health education systems in Lao PDR.

Cholera↗
PubMed1995

Sarin poisoning in Matsumoto, Japan.

A presumed terrorist attack with sarin occurred in a residential area of the city of Matsumoto, Japan, on June 27, 1994. About 600 residents and rescue staff were poisoned; 58 were admitted to hospitals, and 7 died. We examined clinical and laboratory findings of 264 people who sought treatment and the results of health examinations on 155 residents done 3 weeks after the poisoning. Findings for severely poisoned people were decreases in serum cholinesterase, acetylcholinesterase in erythrocytes, serum triglyceride, serum potassium and chloride; and increases in serum creatine kinase, leucocytes, and ketones in urine. Slight fever and epileptiform abnormalities on electroencephalogram were present for up to 30 days. Examination revealed no persisting abnormal physical findings in any individual. Acetylcholinesterase returned to normal within 3 months in all people examined. Although subclinical miosis and neuropathy were present 30 days after exposure, almost all symptoms of sarin exposure disappeared rapidly and left no sequelae in most people.

Acute Disease↗
PubMed1995

[Anesthetic management of Nd-YAG laser surgery in the airway using a larengeal mask].

We used a laryngeal mask for Nd-YAG laser operations of airway stenosis due to tracheal granulation, broncheal granulation and subglottic tumor. Anesthesia was induced with inhalation of N2O-O2-sevoflurane in two cases and intravenous thiopental in one case. The laryngeal mask was inserted with intravenous injection of vecuronium. Anesthesia was maintained with N2O-O2-sevoflurane with intermittent positive pressure ventilation. Laryngeal mask airway was stable with respect to circulation and respiration during Nd-YAG laser irradiation. Ignition of a laryngeal mask caused by Nd-YAG laser is much less common compared to that of a tracheal tube with cuff. Therefore, we recommend to use laryngeal mask airway for Nd-YAG laser operation of airway stenosis because of much less danger of ignition and because it keeps good cardiovascular and respiratory conditions.

Adult↗
PubMed1994

[A comparative study of nitric oxide (NO) gas solution, L-arginine and D-arginine on superoxide anion radical generation using human polymorphonuclear leukocytes].

Nitric oxide (NO) has been studied from various aspects since NO had been recognized as an endothelium-derived relaxing factor (EDRF). We studied the effect of NO gas solution, L-arginine and D-arginine on superoxide anion radical (O2-) generation using human polymorphonuclear leukocytes by chemiluminescence method. NO gas solution inhibited O2- generation induced by fMLP or PMA in a dose-dependent fashion, whereas L-arginine that in NO precursor increased O2- generation. On the other hand, D-arginine which is an optical isomer, had no effect on O2- generation. These results suggest that L-arginine administered externally may be different from endogenous L-arginine and has a different effect on O2- generation. Therefore, we must pay attention to biological effects of L-arginine when experiments are performed on nitric oxide.

Arginine↗
PubMed1994

[The changes in superoxide anion production in neutrophils on ischemia-reperfusion].

It is generally known that ischemic reperfusion injury is caused by cell membrane injuries due to superoxide. The present study was carried out to clarify an increase of superoxide production in human neutrophils in state of hypoxia and hyperoxia in vitro. Superoxide of neutrophils was studied at various PO2 values (air, 100% O2, 50% O2, and 100% N2 gas) by chemiluminescence method. The superoxide production (O2-) rates were 84% (air), 84% (100% N2), 87% (100% O2) and 84% (50% O2), respectively. At these stages, PO2 values were 178, 36, 764 and 370 mmHg, respectively. Since superoxide is generated in mitochondria under PO2 of 1 mmHg, it was considered that these different values of PO2 (100% N2, 100% O2 and 50% O2) do not influence the superoxide production. Other factors, such as PAF or cytokine, were speculated to increase superoxide production.

Cells, Cultured↗
PubMed1993

CELSS nutrition system utilizing snails.

At the 40th IAF Congress in Malaga, a nutrition system for a lunar base CELSS was presented. A lunar base with a total of eight crew members was envisaged. In this paper, four species of plants--rice, soybean, lettuce and strawberry--were introduced to the system. These plants were sufficient to satisfy fundamental nutritional needs of the crew members. The supply of nutrition from plants and the human nutritional requirements could almost be balanced. Our study revealed that the necessary plant cultivation area per crew member would be nearly 40 m3 in the lunar base. The sources of nutrition considered in the study were energy, sugar, fat, amino acids, inorganic salt and vitamins; however, calcium, vitamin B2, vitamin A and sodium were found to be lacking. Therefore, a subsystem to supply these elements is of considerable value. In this paper, we report on a study for breeding snails and utilizing meat as food. Nutrients supplied from snails are shown to compensate for the above mentioned lacking elements. We evaluate the snail breeder and the associated food supply system as a subsystem of closed ecological life support system.

Animals↗