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Biomedical subjects

J Koike

Publications and source records attributed to J Koike.

At least 55 records · Page 3Linked to original sources
PubMed1998

Analysis of water in Autonomous Biological Systems (ABS) samples.

Several soluble components, peptidase and amino acids, and carbon isotopic ratio in the water retrieved from flight experiments of Autonomous Biological Systems (ABS) as well as ground control samples are analyzed to interpret the condition, dynamics, material balance of the ABS ecosystems. Organic carbons in flight samples were found to be more abundant compared with the control ones, which suggested the uniform ecosystems in low gravity might easily dissolve more soluble components. The Mir-1997 flight sample showed higher C/N ratio probably because of the dissolution of carbon-rich plant materials.

Alkaline Phosphatase↗
PubMed1998

Microorganisms and plant of Autonomous Biological Systems (ABS) samples.

Distribution of microorganisms and cellular structure of an Autonomous Biological Systems (ABS) were studied with a special attention to the effect of space environments. Viable cell densities measured by the direct fluorescence microscopic method were in the order of 10(5) cells/ml for fractions 1 (upper suspension) and 2 (lower suspension), and 10(6) cells/ml for fraction 3 (sediments). These values were 10 to 100 times larger than the values obtained by the classical colony forming unit method. No difference between flight and ground samples was observed in the vertical distribution of viable microorganisms when fractionation and analysis were carried out after recovery. Intracellular distribution of chloroplasts in higher green plants, Ceratophyllum demersum, of flight samples was disturbed after 10 days of flight (24hrs/day light on). After 4 months of flight (Mir/STS-79/81) with 24 hrs light on, Ceratophyllum demersum was completely disintegrated. On the other hand, in the second 4-months-flight experiment with 16 hrs/day light on, Ceratophyllum demersum was only slightly deteriorated.

Aquaculture↗
PubMed1998

Performance of a digital video camcorder for the Autonomous Biological System experiment onboard Space Station Mir.

A video imaging and recording system was utilized in the Autonomous Biological System experiment onboard the space station Mir. Video image of the mini-ecological system was successfully recorded. The whole system was retrieved to the ground after its operation in orbit for four months. Performance of the video system is summarized here together with technical problems encountered. Defects of pixel had been developed in the imaging device. Cause of these defects could be attributed to its exposure against space radiation. Auto white balance was another function of the camcorder that was deviated from normal range of its performance once in orbit but recovered to normal after a while. Possible use of imaging devices for dosimetry is proposed to record space radiation environment at the site close to the experiment.

Animals↗
PubMed1998

Concluding remarks of Autonomous Biological Systems (ABS) experiments.

Team efforts for analysis on the Autonomous Biological Systems (ABS) space experiments are summarized here to conclude scientific findings, and to scope the extended studies in future. From the three experiments on Space Shuttle and Space Station Mir, a closed ecological system modeled by the ABS was verified to be capable of sustaining its members of animals and plants under space environment for a period of several months. The animals successfully completed their life cycle in space during the course of these experiments, this was the first time that the life cycle of higher organisms had been completed in space and ecological system. Importance of gravity for ecology was proven at the same time. Gravity is a dominant factor for ecology by formulating spatial patterns and distribution of members of ecological system. Under microgravity, the fate of ecological system was found highly sensitive against the variation of environmental factor, such as light illumination cycle.

Amino Acids↗
PubMed1997

Undectable expression of hMLH1 protein in sporadic colorectal cancer with replication error phenotype.

PURPOSE: Four DNA mismatch repair genes have been identified as being susceptible genes for hereditary nonpolyposis colorectal cancer. Deficiency of one of the mismatch repair genes causes the replication error phenotype in more than 80 percent of patients with hereditary nonpolyposis colorectal cancer and in 10 to 30 percent of patients with sporadic colorectal cancer. To determine which mismatch repair gene is lacking the function in patients with replication error-positive colorectal cancer, several approaches have been used at the nucleic acid and protein levels. We studied replication error in 40 samples of randomly selected colorectal cancers and expression of hMSH2 and hMLH1 proteins analyzed by immunoblot in the tumor and normal tissues of the replication error-positive and replication error-negative samples. MATERIALS AND METHODS: Frozen tumor and normal tissues were obtained from 40 Japanese patients who had colorectal cancer. According to the Amsterdam criteria, those patients were classified as having 39 sporadic and 1 unknown colorectal cancers. Genomic DNA was extracted from tumor and normal tissues for determining replication error with eight microsatellite markers. Expression of hMSH2 and hMLH1 proteins in cell lysates of tumor and normal tissues of 16 patients was analyzed by immunoblot. RESULTS: The replication error phenotype was found in 6 (15 percent) of the 39 sporadic cases. hMLH1 protein was not detected in two of the six replication error-positive tumor tissues and not in the normal tissues, indicating that the tumor cells of the two patients had severe mutations in both alleles of the hMLH1 gene. Another four replication error-positive and ten replication error-negative tumors and normal tissues expressed hMLH1 protein. hMSH2 protein was detected in all samples. CONCLUSION: hMLH1 protein was undetectable in the two tumor tissues of the six replication error-positive samples of sporadic colorectal cancer. The detection procedure used here may have potential use for determining a dysfunctional mismatch repair gene product.

Adaptor Proteins, Signal Transducing↗
PubMed1997

Quasi-steadiness approximation for the two-compartment solute kinetic model.

We analytically solved the equation of the variable volume, two-compartment solute kinetic model (TCSKM). From the solution, we constructed an expression of weekly concentration profiles developing in the patient's body by routine hemodialyses. Obtained formulas can be used to calculate Kt/V, solute reduction index (SRI), the solute generation rate (G) per unit distribution volume (V), and a mass transfer coefficient (MTC) between the two compartments. To estimate these parameters, the formulas only need three-point data during a dialysis, that is, pre-, one-hour, and post-dialysis solute concentrations instead of four that would otherwise be needed. A 48 hour data point is not required. The weekly concentration profiles can be easily calculated by the formulas. As examples of clinical applications, we calculated Kt/V, G/V, and SRI of urea, Cr, and uric acid using plasma data of 121 hemodialyzed patients. Then the results were compared with the single-compartment solute kinetic model (SCSKM). The obtained mean MTC/V values, that is, 1.08 (1/hr) for urea, 0.53 (1/hr) for Cr, and 1.11 (1/hr) for uric acid, were consistent with the previous works. SCSKM overestimated the mean G/V by 7.1%, 15.9%, and 10.0%, and the mean SRI by 6.7%, 18.6%, and 10.0%, for urea, Cr, and uric acid, respectively. The solute distribution volume ratio of TCSKM to SCSKM, (V)TCSKM/(V)SCSKM, depended on the value of MTC/V and the hemodialysis duration. Using pedometers, we measured the total number of steps the patients took during a week. We found that the total number of steps in a week was significantly correlated with the Cr generation rate (r = 0.285, P < 0.03), but that it was not significantly correlated with the other generation rates (r = 0.204, P > 0.09 for urea, and r = 0.209, P > 0.08 for uric acid). These data suggest that the Cr generation rate is related to the patient's physical activity. We conclude that the formulas can estimate an adequate dialysis prescription for the hemodialyzed patient.

Humans↗
PubMed1997

[Acute acalculous cholecystitis as a complication of cerebrovascular disease].

Acute acalculous cholecystitis (AAC) is a potentially life-threatening complication, which is sometimes found in patients with multiple injuries, burns, or after an operation. It is unclear, however, whether AAC occurs after cerebrovascular disease (CVD). We studied the incidence of AAC complicating CVD and the clinical characteristics of AAC that occurs after CVD. One thousand three patients with CVD were studied who had been admitted at the acute stage to Kenwakai Hospital from January 1989 through September 1995 and to Seguchi Hospital of Neurosurgery from January 1993 through September 1995. There were 557 patients with cerebral infarction, 273 with cerebral hemorrhage, 94 with subarachnoid hemorrhage, and 79 with TIA/RIND. Twelve patients developed acute cholecystitis, ten of whom had AAC. Of the ten patients with AAC, six had cerebral infarction, two cerebral hemorrhage, and two TIA/RIND. Eight of ten were male. The incidence of AAC was 1.0% in the CVD patients studied. The majority of the AAC patients showed severe hemiparesis. The time interval from CVD to the onset of AAC ranged from 1 to 89 days, with a mean of 25.1 days. AAC occurred 0 to 16 days (mean 5.8 days) after the start of oral or tube food intake in five patients. The most common initial symptom was fever (70%), whereas abdominal pain was infrequent (20%). All the patients showed elevated CRPs and abnormal ultrasonographic findings for the gallbladder and some also had leukocytosis (60%) and elevated aminotransferase of more than 100 IU/l (30%). Cholecystectomy was performed on four AAC patients, but five were successfully treated with antibiotics. The cause of AAC complicating CVD seems to be multifactorial and probably is related to fasting, increased bile concentration, and arteriosclerosis. Our results strongly suggest that AAC is an unrecognized but important complication during acute stage CVD patients.

Acute Disease↗
PubMed1997

Effects of oral adsorbent AST-120 on the progression of chronic renal failure: a randomized controlled study.

This prospective, randomized controlled study was designed to examine the effects of oral adsorbent AST-120 on the progression of chronic renal failure (CRF) in patients on a strict low protein diet (LPD). Twenty-six patients with CRF (serum creatinine 3.0 to 8.6 mg/dl) on a LPD were randomly assigned to a control group (N = 13) or an AST-120 group (N = 13). The 1/Cr slope and creatinine clearance (CCr) slope were used to estimate the progression rate of CRF; uremic toxins, serum and urinary indoxyl sulfate (IS), peak 2a and guanidino substrates (GS) measured by HPLC. Comparisons were made between the baseline observation period for 6 to 12 months and the treatment period (0.6 g/kg/day of LPD alone or concurrent with 6 g/day of AST-120, for the control and the AST-120 groups, respectively) for 12 to 24 months in both groups. Both the 1/Cr slope and CCr slope were significantly lessened in the treatment period only in the AST-120 group. Serum and urinary IS, but neither peak 2a nor GS were significantly decreased in the treatment period only in the AST-120 group. We conclude that AST-120 administration concurrent with LPD may be superior to LPD alone in retarding the progression of CRF by inhibiting accumulation of indoxyl sulfate.

Carbon↗
PubMed1996

Fundamental studies concerning planetary quarantine in space.

If there is a possibility that the organisms carried from Earth to space can live for a significant period on planets, the contamination of planets should be prevented for the purpose of future life-detection experiments. In connection with quarantine for interplanetary missions, we have examined the survivabilities of terrestrial microorganisms under simulated space conditions. In this study, examined the survivabilities of terrestrial organisms under simulated Mars conditions. The Mars conditions were simulated by ultraviolet (UV) and proton irradiation under low temperature, high vacuum, and simulated gaseous conditions. After exposure to the simulated Mars condition, the survivabilities of the organisms were examined. The spores of Bacillus subtilis and Aspergillus niger, some anaerobic bacterias and algaes, showed considerably high survivabilities even after UV and proton irradiation corresponding to 200 years on Mars. This subject is not restricted to academic curiosity but concerns problems involving the contamination of Mars with terrestrial organisms carried by space-probes.

Bacteria↗
PubMed1996

Quasi-steadiness approximation for the single-compartment urea kinetic model (SCUKM).

Using SCUKM, we constructed recurrence formulae expressing weekly pre- and post-dialysis urea levels. Then we mathematically derived simple methods to estimate Kt/V0 and the urea generation rate (G) per unit urea distribution space post-dialysis (V0), which only required the measurement of pre- (C) and post-dialytic blood urea concentrations (C0) of a single hemodialytic session (two-point method). Underlying fundamental assumptions were: (i) patients receive weekly scheduled hemodialysis; (ii) the ultrafiltration rate, intradialytic urea generation, interdialytic water increase rate, and residual renal function are small enough to be retained only as the leading term in the formulae. In the derivation, we proved relations: C = f(Kt/V0)G/V0, and C0 = g(Kt/V0)G/V0, which state that both C and C0 are directly proportional to G/V0, and that the proportional constants are functions of Kt/V0. Errors of the formulae were also checked to make the limitation of the approximations clear. The present formulae exactly reproduced Kt/V0 and G/V0 of virtual patients strictly obeying the SCUKM in a computer simulated model. Using the blood urea nitrogen concentration data of 20 actual patients, we compared our method with the usual three-point method and obtained substantial correlations between them (r = 1.00 for Kt/V0, r = 0.98 for G/V0). Finally, we proposed convenient and easily calculable new formulae, which give sufficiently accurate Kt/V0 and G/V0.

Blood Urea Nitrogen↗
PubMed1996

Involvement of cell-mediated killing in apoptosis in histiocytic necrotizing lymphadenitis (Kikuchi-Fujimoto disease).

Histiocytic necrotizing lymphadenitis, also called Kikuchi-Fujimoto (KF) disease, is a benign disorder characterized histologically by paracortical necrotic foci surrounded by histiocytic aggregates. We analysed affected lymph node tissues from 34 patients with the disease in an attempt to elucidate its histogenesis. The 'necrotizing' cells showed typical apoptotic changes, including cell shrinkage and condensed and fragmented nuclei. Apoptotic bodies with a peculiar ultrastructure were demonstrated, and DNA fragmentation was detected in these cells by in situ end labelling. Immunostaining for the apoptosis-regulating proteins bcl-2, bax, c-myc and p53 failed to show their involvement in KF disease. However, perforin, a killer cell-specific cytolytic protein essential for provoking apoptosis in target cells, was found to be expressed abundantly by the infiltrating cells, which were thought to be cytotoxic T-lymphocytes. Perforin-expressing cells were present in the apoptotic foci of 28 of the 34 patients (82.4%). Virtually no cells containing perforin granules were present in non-pathological regions, lymph node tissues from control subjects with reactive or tuberculous lymphadenitis or those from patients with KF disease with negligible apoptosis. Therefore, the 'necrosis' associated with KF disease appears to be attributable to trans apoptotic death of the killer cell target in the affected nodes. We propose that KF disease should be called apoptotic lymphadenitis.

Adolescent↗
PubMed1996

Role of urinary arginine vasopressin in the sodium excretion in patients with chronic renal failure.

Patients with chronic renal failure show almost equal levels of sodium excreted in the urine as healthy subjects through an increase of the fractional excretion sodium (FE(Na)). The mechanisms of this adaptation, however, are unknown. Recently, urinary arginine vasopressin (AVP) has been shown to inhibit the antidiuretic action of plasma AVP in the collecting ducts of rabbits and rats. In this article, the roles of plasma and urinary AVP are examined with other hormones in the sodium excretion of 57 patients with chronic renal disease. The fractional excretion of AVP, plasma atrial natriuretic peptide (ANP) and endothelin-1 (ET-1), urinary ET-1, and FE(ET-1) correlated with the decrease of creatinine clearance (Ccr). Multiple and stepwise regression analyses showed that FE(AVP) is the major dependent determinant for FE(Na) (adjusted r2 = 0.78). These results suggest that the increase of AVP excretion per remaining nephron could be a cause of the increase of FE(Na) in patients with renal failure. Although plasma AVP works as an antidiuretic hormone, urinary AVP serves as an intrinsic diuretic, especially in patients with chronic renal failure.

Adolescent↗
PubMed1996

Mini ecosystem in space--preliminary experiment on board STS-77.

An enclosed ecosystem which is stable on Earth will behave differently when brought into space. Micro-gravity and radiation will affect the dynamics of material circulation or the activities of small creatures of the ecosystem. One series of space experiments aiming to address such issues was planned in the United States (It is termed as ABS--Autonomous Biological System) and Japanese group has been involved with cooperating with the analysis of the flight samples. Before the ecosystem will be on board Russian Space Station "Mir" later 1996 for 3 months, a preliminary flight was carried out in May 1996 on Space Shuttle (STS-77) for 10 days flight. It was the first of such experiments to fly one whole ecosystem in space.

Animals↗
PubMed1996

[Warning! A crucial period of searching for life on Mars--why international criterion for space quarantine is now required].

In connection with quarantine for interplanetary mission, we have examined the survivalities of terrestrial microorganisms under simulated Mars condition. In this study, the Mars conditions were simulated by ultraviolet and proton irradiation under similar low temperature, high vacuum and gaseous conditions by using cryostat vehicle. After exposure to the simulated Mars conditions, the survivabilities of the organisms were examined. From the results, the spores of Bacillus subtilis, the spores of Aspergillus niger, some anaerobic bacteria and algae showed considerable high survivalities even after UV and proton irradiations corresponding to 200 years on Mars. This subject is not restricted to academic curiosity but concerns problems involving the contamination of Mars with terrestrial organisms carried by space-probes. If there is a possibility that the terrestrial organisms carried from Earth to Mars can live for a significant period on Mars, a contamination of the Mars should be prevented for the purpose of life-detection-experiments in future.

Aspergillus niger↗