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Biomedical subjects

K Hara

Publications and source records attributed to K Hara.

At least 739 records · Page 41Linked to original sources

A model of the mechanisms of long-term potentiation in the hippocampus.

Long-Term Potentiation (LTP) in the hippocampus has been considered to be a phenomenon closely related to learning and memory in the brain. In this paper, an integrated model of LTP is constructed based on hypotheses about both the mechanism of LTP induction and that of LTP maintenance, that is, the NMDA-receptor channel, protein phosphorylation and protein turnover. The validity of the model is discussed based on the results of computer simulations.

Animals↗

A simple, rapid and simultaneous analysis of complex volatile hydrocarbon mixtures in blood using gas chromatography/mass spectrometry with a wide-bore capillary column.

A screening method for detecting volatile hydrocarbons in blood has been developed using gas chromatography/mass spectrometry with a wide-bore capillary column and a headspace method. Toluene-d8 and indan were used as the internal standards for quantitative analysis. Hydrocarbons with retention indices from 600 to 1200 were simultaneously and quantitatively detected in relatively low concentrations (0.01 microgram/ml) in reconstructed ion chromatography. This method could prove useful in forensic cases in which urgent examination of complex hydrocarbon mixtures, e.g. petroleum components, is required.

Cause of Death↗

Regulatory DNA sequence conserved in the course of BK virus evolution.

Within the genome of human polyomavirus BK (BKV), there exists a noncoding regulatory region toward the late region side of the origin of DNA replication. In most BKV strains isolated by viral culture, this regulatory region contains tandem repeats varying in size. Recently, however, several laboratories isolated new BKV strains (designated as archetypal strains) lacking such repeat sequences. To examine the genetic relationship between archetypal strains, a phylogenetic tree was constructed for seven BKV strains, including three archetypal strains, from DNA sequence data on the late genes, those for leader protein (agnoprotein), and those for structural proteins (VP1, VP2, and VP3). For three strains data previously reported were used, whereas for the others sequences were determined in this study. From total numbers of nucleotide substitutions in each pair of strains, a phylogenetic tree was constructed by the unweighted pair-group method. The phylogenetic tree obtained reveals that BKV strains containing the archetypal regulatory region do not constitute a cluster of closely related strains and that these strains, together with those carrying the major part of the archetypal regulatory region, are widespread in the BKV population. This finding suggests that the basic structure of the archetypal regulatory region has been conserved in the course of BKV evolution.

BK Virus↗

Phase II study of (glycolate-O,O') diammineplatinum(II), a novel platinum complex, in the treatment of non-small-cell lung cancer.

A total of 68 patients with non-small-cell lung cancer who either had not previously been treated (38) or had undergone prior therapy (30) were treated in a phase II study of (glycolate-O,O') diammineplatinum(II) (NSC 375 101D; 254-S), a new platinum complex. The drug was given as a single intravenous infusion at a dose of 100 mg/m2 every 4 weeks. All 68 patients could be evaluated for response and 62, for toxicity. Objective responses were seen in 10 of 68 cases (14.7%; 95% confidence interval, 7.3%-25.4%), and the median duration of response was 15 weeks (range, 8-23 weeks). The response rates were similar for previously untreated and treated patients (13% and 17%, respectively), including three previously treated with cisplatin. Myelosuppression was the dose-limiting toxicity. Thrombocytopenia (less than 100,000 platelets/mm3) and leukocytopenia (less than 3,000 WBC/mm3) were observed in 22 (35%) and 18 (29%) patients, respectively. Mild to moderate nausea and vomiting occurred in 45 cases (73%). No significant renal or neurotoxicity was observed. We conclude that as a single agent, 254-S is well tolerated but appears to have marginal activity against non-small-cell lung cancer.

Adenocarcinoma↗

Relationship between heart rate and rhythm, and cardiac performance assessed in the human fetus in utero.

To evaluate the relationship between heart rate and rhythm, and cardiac performance, in the human fetus in utero, observed over a long-term period in gestation, we made a total of 138 studies in 114 fetuses from 18 to 41 weeks of gestation; 104 having heart rate changes without rhythm disturbances ("control group"), 6 with complete atrioventricular block and 4 with supraventricular tachycardia. Using M-mode echocardiogram, we measured end-diastolic dimension and fractional shortening in the right and left ventricles. The corresponding heart rate for each cardiac cycle was measured using the interval between two consecutive end-systolic points. In fetuses in the group of controls, the values for fractional shortening in both ventricles were almost constant with advancing gestational age, unrelated to an increase in end-diastolic dimensions of either ventricle. There was no correlation between changes in heart rate and changes in the value of ventricular fractional shortening at any period of gestation studied. In the fetuses with atrioventricular block, dimensions and fractional shortenings in both ventricles were significantly larger than those in the group of control fetuses at the same stage of gestation. This indicates that the fetal heart is capable of acclimatizing itself, beginning as early as 18-25 weeks of gestation, to long-lasting bradycardia in which an increased stroke volume would be required. In fetuses with supraventricular tachycardia, end-diastolic dimensions were larger and fractional shortening was significantly smaller in both ventricles than in fetuses from the control group from 26-30 weeks of gestation onwards. This suggests tachycardia-induced cardiomyopathy occurring during intrauterine life.

Echocardiography↗

An experimental model of death from anaphylactic shock with compound 48/80 and postmortem changes in levels of histamine in blood.

The present study was made on an experimental animal model of a death from anaphylaxis, in which postmortem changes in levels of histamine and 1-methylhistamine, in whole blood were measured. Instead of the usual immunological method administering compound 48/80, a degranulating agent of mast cell and the effect closely resembling the immuno-reaction, resulted in reliable death in a short time. The animals that died rapidly after the injection of compound 48/80, were found to have large increases in levels of histamine and 1-methylhistamine soon after the administration. These results were similar to the results of injecting histamine exogenously. On the other hand, the animals that died after a longer time showed no increases in levels of those amines within about 24 h, but 24 hours after death histamine levels were only increased tremendously without rise in 1-MHA levels. These phenomena closely resembled those in the control animals that were treated with overdoses of Nembutal.

Adult↗

Methamphetamine and amphetamine concentrations in postmortem rabbit tissues.

The feasibility of detecting methamphetamine and its major metabolite, amphetamine, in postmortem tissues over a 2-year period was examined. It is important to determine if the abuse and toxic effects of drugs can be proved from evidence found in decayed, submerged, or stained tissue materials. The blood, urine, liver, skeletal muscle, skin and extremity bones from rabbits given methamphetamine intravenously were kept at room temperature, under 4 different conditions: sealed in a test tube, dried in the open air, submerged in tap water and stained on gauze. Methamphetamine was present in all the samples, with slight change in concentration in case of sealed and air dried tissues. Changes varied in bones kept in water. There were considerable decreases in methamphetamine in blood and urine stains. Despite long term storage, drug abuse and/or toxicity could be determined, in all tissues examined.

Amphetamine↗

High incidence of urinary JC virus excretion in nonimmunosuppressed older patients.

Urine specimens from 120 patients attending urologic clinics were screened by blot hybridization for the presence of a polyomavirus DNA. Detected viral DNA was then identified as BK or JC by fine restriction enzyme analysis. BK and JC viral DNA was found in 5 (4%) and 35 (29%) patients, respectively. Detection rates were compared among three age groups: 0-29, 30-59, and 60-89 years. Detection of JC viral DNA increased with age and reached the highest value (45%) in the group aged 60-89 years. For BK viral DNA a correlation between detection and age was not clear because the rate of detection was low, although the highest rate (9%) occurred in the oldest group. To confirm the active urinary excretion of polyomavirus DNA in older patients, urine specimens from 23 patients (60-90 years) treated at an internal medicine clinic were examined for viral DNA. BK and JC viral DNA were in 2 (9%) and 12 patients (52%), respectively. These results suggest that JC virus is frequently reactivated in older individuals.

Adolescent↗

The microbial flora from root canals and periodontal pockets of non-vital teeth associated with advanced periodontitis.

Microflora from root canals and periodontal pockets of periodontally affected teeth were compared in order to elucidate the as yet unknown relationship between pulpal and periodontal disease. Caries-free teeth affected with advanced periodontitis and diagnosed as clinically dead by electric pulp testing were selected. The root canals and periodontal pockets were sampled, and the bacterial flora examined by both culture and interference microscopy. The results indicated that the aerobe/anaerobe ratio in the periodontal pocket was 0.23, while it was 0.0022 in the root canal, the large predominance of obligate anaerobes reflecting the anaerobic environment found in the root canal. Morphological classification obtained from interference microscopy showed similar proportions of morphotypes in the two sites. Results of anaerobic culture demonstrated a significantly higher rate of detection of facultative Streptococcus bacteria in the periodontal pocket than in the root canal. The predominant bacterial species common to both regions were Streptococcus, Peptostreptococcus, Eubacterium, Bacteroides, and Fusobacterium for obligate anaerobes. As for facultative anaerobes, Actinomyces and Streptococcus were detected predominantly in the periodontal pocket. The occurrence of micro-organisms common to both sites in this study suggests that the periodontal pocket may be a possible source of root canal infections.

Actinomyces↗

Duration patterns of percussion sound in healthy and periodontally affected teeth.

Ten periodontally affected subjects and 10 healthy subjects were selected in order to examine the duration patterns of percussion sounds in all upper teeth, excluding the 8's. Probing depth, loss of attachment, tooth mobility by 'Periotest', bone loss and percussion sound duration via occlusal sound analyser were recorded during the pretreatment period. The following results were obtained from the study: (i) the normal duration of percussion sounds ranged from 4.40-5.33 ms; (ii) percussion sound values of periodontal patients were of longer duration than those of healthy subjects; (iii) a close correlation between duration and other individual parameters was found in all upper teeth, with the exception of molars.

Acoustics↗

[Investigation on the etiology of sepsis by using experimental mouse model with leukocytopenia. 3. The role of Kupffer cells in the etiology of bacteremia].

In the previous report, we showed that the reticuloendothelial system (RES), especially the liver, played an important role in the etiology of bacteremia or sepsis as the major protective system. In this study, to investigate the role of Kupffer cells in the etiology of bacteremia, we isolated and cultured murine Kupffer cells using a technique involving perfusion with collagenase and DNase. We compared the adherence and phagocytosis rate of two groups of isolated bacteria from bacteremic mice by these cells. One group was bacteria causing systemic bacteremia consisted of P. aeruginosa and M. morganii, and the other was bacteria causing portal bacteremia consisted of E. coli, E. cloacae, K. pneumoniae and Enterococci. As a consequence, the following facts were revealed. 1. The bacterial phagocytosis and adherence rate by Kupffer cells were significantly higher in bacteria causing portal bacteremia than in bacteria causing systemic bacteremia. These data were correlated to each blood clearance rate from mice. 2. Blood clearance rate reflected mainly adherence of Kupffer cells to bacteria, and it was suggested that these adherence were one of the most important factor to protect the hosts from the advance of bacteremia from the portal to the systemic. 3. In the case of using peritoneal macrophage, we couldn't find the same correlation, so the possibility was suggested that the above phenomenon was specific to Kupffer cells.

Animals↗

[Clinical and bacteriological studies in four cases of pulmonary infection caused by Protomonas extorquens].

A novel bacterium, Protomonas extorquens was isolated from sputum, pleural effusion and ascitis in four cases of pulmonary infection by buffered charcoal yeast extract agar (B-CYE) which was generally used for Legionella spp. Three cases were so-called immunocompromised hosts (2 malignant diseases, 1 renal failure), and they died from underlying diseases. Protomonas extorquens was newly named by Komagata in 1984, which was characterized by production of pink pigment, growth in methanol medium and positive production of oxidase and catalase. This organism is ordinarily isolated from soil and dead leaves. This is the first report for isolation of P. extorquens from clinical specimens in Japan and it seems to have a significant role in immunocompromised hosts.

Adult↗

[Isolation of methicillin-resistant Staphylococcus aureus (MRSA) at the Hokusho Central Hospital--observation during the recent 4 years].

Clinical and bacteriological studies were carried out to investigate the isolation of MRSA from clinical materials, during the 4 years from 1985 to 1988 at the Hokusho Central Hospital. The isolation frequency of MRSA from Staphylococcus aureus increased from 5.6% (3 strains) in 1985 to 50.0% (90 strains) in 1988. MRSA from sputum and pressure sore increased significantly. However MRSA from outpatient and inpatient in the ward for common people were constant, about 20%. Inpatients in the ward for aged person were increased significantly from 13.6% (3 strains) to 67.0% (67 strains). Most of the patients with positive MRSA isolation had background diseases (88.3%) and were bedridden (78.4%). Patients with cerebrovascular disease were 55.9% of all of the cases. But most of the MRSA strains were resistant to CZX, FOM, DMPPC, CMX, CEZ, CZON, CZX, most of the MRSA strains were sensitive to RFP, VCM, MINO, IPM/CS.

Anti-Bacterial Agents↗

[A case of fatal sepsis due to Vibrio vulnificus].

A 66-year-old male with chronic alcoholic liver injury was admitted on July 27, 1986 to our hospital with complaints of high fever, convulsion and skin erythema. He had consumed raw fish 3 days before, and had a scratch wound over the right arm and left leg because he had slipped in a small stream in the woods the day before admission. He was already in shock state with sepsis of V. vulnificus and DIC on admission. Although the treatment with ABPC, CP, CAZ, MINO for sepsis, and Heparin & Antithrombin III for DIC was immediately begun, he died only 10 hours after admission. On autopsy, the skin lesion revealed phlegmon with necrotizing angitis and the liver showed fatty changes with Mallory's body. The causative organism was detected from the blood and on autopsy from the skin wound, bile juice, liver, spleen, kidney and bone marrow, and its type was determined as a V. vulnificus serovar 4. It was suspected that the route of infection in this case was the raw fish rather than via the wound because the water in which he had been wounded was fresh water and the bacterium was not detected from the water, shells, nor moss existing there.

Aged↗

[Studies on defense effects of recombinant human granulocyte colony-stimulating factor (G-CSF) to infections. II. Priming effect for superoxide production by human neutrophil].

In present study, we have investigated superoxide (O2-) production from human neutrophils by recombinant human granulocyte colony-stimulating factor (G-CSF) using the microtiter plate for the purpose of being close to the inflammatory site. G-CSF by itself did not induce the release of O2- in human neutrophil on either Fetal Bovine Serum (FBS)-coated plate or plate uncoated with FBS, even if neutrophils were exposed for maximum 3 hr. However, the optimal concentration of G-CSF (50 ng/ml) was able to prime human neutrophils with enhance of O2- release stimulated by the chemotactic peptide, N-formyl-methionyl-leucyl-phenylalanine (FMLP) from 10(-6) to 10(-8) M, but not by the non chemoattractant such as phorbol myristate acetate (PMA), concanavalin A, and ionomycin. These findings indicate that G-CSF might enhance bactericidal activity of neutrophils by priming them penetrating into the inflammatory site.

Cells, Cultured↗

[Comparison of D-arabinitol, candida antigen, and beta-glucan, measured by the chromogenic limulus assay, in the rabbit model of systemic candidiasis].

In this study, we measured D-arabinitol, candida antigen and beta-glucan in the rabbit model of systemic candidiasis. It was recently reported that the factor G, one of the coagulation enzymes from the horseshoe crad amebocyte lysate, reacts with beta-glucan or polysaccharide from fungus, and not with endotoxin. The newly developed endotoxin specific chromogenic Limulus assay (endospecy test), which is devoid of factor G, did not react with any rabbit serum. But the beta-glucan measured by the conventional Limulus assay (toxicolor test), which contains the factor G, was elevated (from 10 pg/ml to 100 pg/ml) in all cases of rabbit model of system candidiasis. Serum D-arabinitol, measured by Sone's enzymatic fluorometric method, increased in all cases, but Cand-Tec (candida detection system by latex agglutination) showed only one positive case in five innoculated rabbits.

Animals↗