Asymmetric transfer of DNA strands in bacterial conjugation.
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Centrifugation, Density Gradient↗
Biomedical subjects
M Ohki
Publications and source records attributed to M Ohki.
Effects of donor age and contamination level of dioxins and related chemicals on frequency of sister chromatid exchanges in human lymphocytes cultured in vitro.
Frequencies of sister chromatid exchanges (SCEs) of human lymphocytes in control (DMSO treated) and 7,8-benzoflavone (ANF) treated cultures were measured in 39 healthy Japanese people and examined in connection with donor age. Both the control (baseline) and ANF induced SCE rates were significantly enhanced with age and highly positive correlation was observed between them. Therefore, in vivo aging seemed to have some effects on the frequencies of SCEs in human lymphocytes cultured in vitro. Concentrations of PCDDs, PCDFs and Co-PCBs in the blood and sebum of face were determined in the same Japanese subjects. Significantly positive correlation was observed between the blood and sebum in their total TEQ levels. Hence, PCDDs, PCDFs and Co-PCBs, which have been contaminating human bodies, are considered proportionally excreted from the sebum of face or body. Their total TEQ concentrations were also meaningfully increased with donor age in the sebum of face as well as in the blood. Either the baseline or ANF induced SCE frequencies was not enhanced with the total TEQ levels in the blood. Therefore, background levels of their contamination seem not to affect the SCE rates of the lymphocytes in the control and ANF treated cultures.
Adult↗
Comparison between "Yusho" patients and healthy Japanese in contamination level of dioxins and related chemicals and frequency of sister chromatid exchanges.
Highly toxic organochlorine chemicals such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (CoPCBs) were determined in the peripheral blood and sebum from the face of 16 "Yusho" patients of about 27 yr after the outbreak of Yusho accident, and 39 healthy Japanese people. The mean total toxic equivalent (TEQ) levels of PCDDs, PCDFs and CoPCBs in the blood were still about seven times higher in Yusho patients than in healthy Japanese at the age of 45 yr and more. The sebum excretion of these chemicals seemed proportional to their blood levels in Yusho patients. These toxic chemicals, however, did not enhance frequencies of sister chromatid exchanges (SCEs) in the control and 7,8-benzoflavone (ANF) treated cultures in Yusho patients. Hence, no significant difference was observed in the mean SCE rates between the Yusho patients and general Japanese people of more than 45 yr of age. In this study, the number of Yusho patients examined is limited, so further large-scale investigations are needed to get more conclusive results concerning the genotoxic potency such as SCE induction.
Adult↗
Effects of contamination level of dioxins and related chemicals on thyroid hormone and immune response systems in patients with "Yusho".
Effects of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (Co-PCBs) on thyroid hormone and immune response systems were examined in 16 Yusho patients at about 30 years after the outbreak of the Yusho accident. Their toxic equivalent (TEQ) levels in the blood were 27.8-1048.5 pg/g fat with the median level of 222.4 pg/g fat, which was about seven times higher than that of healthy Japanese people. Even at such high blood TEQ concentrations, they seemed not to affect the serum levels of thyroid hormones, thyroid stimulating hormone (TSH), immunoglobulins (A, G and M), autoantibodies (antinuclear antibody, rheumatoid and lupus erythematosus (LE) factors), and lymphocyte subsets in the blood. However, positive rates of rheumatoid factor were considered to increase in higher blood TEQ groups. This investigation was done using rather small number of Yusho patients, so further large-scale investigations are needed to get more conclusive findings concerning their effects on thyroid hormone and immune response systems.
Adipose Tissue↗
Effects of exercise on nasal resistance and nasal blood flow.
Nasal resistance and nasal blood flow were measured consecutively before exercise, immediately after exercise, 5, 10, 15, 20, 25, and 30 minutes after exercise in 11 normal subjects and 18 patients with perennial allergic rhinitis. Nasal resistance was measured by Nihon-Koden Rhinorheograph MRP 2100, and nasal blood flow was measured by Periflux PF2, a laser doppler flowmeter. 77% of unilateral nasal cavities in normal subjects and 75% of unilateral cavities in patients with allergic rhinitis showed a decrease of both nasal resistance and nasal blood flow immediately after exercise. However, rates of changes in nasal resistance and in nasal blood flow were not correlated with each other. In the latter period after exercise, there was a discrepancy between nasal resistance and nasal blood flow. A laser doppler flowmeter is considered to measure blood flow in the superficial part of the nasal mucosa. Based upon our results, an intensive stimulus such as exercise seems to induce vasoconstriction in the superficial part as well as in the deeper part of the nasal mucosa. However, it is also suggested that the vessels in the various parts of the nasal mucosa don't always respond in the same way.
Adolescent↗
Nasal resistance and nasal blood flow in postural changes.
Posture greatly influences nasal resistance. To investigate whether nasal blood flow synchronizes with nasal resistance during changes in posture, correlation coefficients were calculated based on findings from both nasal cavities in 14 normal subjects. There was no correlation between nasal resistance and nasal blood flow, except in the left nasal cavity of one subject. Nasal blood flow was measured by a laser Doppler flowmeter, which detects the blood flow in the superficial part of the nasal mucosa. Nasal resistance is regulated mainly by capacitance vessels located in the deeper part of the nasal mucosa. Therefore, the dissociation in nasal resistance and blood flow responses to postural changes noted in our study suggests that vessels in different parts of the nasal mucosa respond differently to this same stimulus.
Adult↗
Nose/mouth distribution of respiratory airflow in 'mouth breathing' children.
Oro-nasal distribution of respiratory airflow was determined in 120 'mouth breathing' children by a minimally invasive computer-assisted method that employed a modified CPAP nasal mask/pneumotach and a head-out body plethysmograph. Resulting measurements were reproducible but clinical assessments correlated poorly with these values. Airflow distribution was almost identical in inspiration and expiration. 100% nasal breathing was found over a wide range of nasal resistances, many subjects with lips apart. Overall, the nasal fraction was negatively correlated with resistance and it was increased by topical decongestant. Decreasing nasal resistance with increasing age was confirmed, but corresponding changes in airflow distribution were not demonstrated. Quantitative assessment is advocated in clinical management of 'mouth breathers'.
Airway Resistance↗
Pharmacologically stimulated portal flow measurement by magnetic resonance imaging for assessment of liver function.
PURPOSE: To evaluate pharmacologically stimulated portal flow measured by magnetic resonance (MR) imaging for assessment of liver function. MATERIALS AND METHODS: Pharmacologically stimulated portal flow was measured by phase contrast MR imaging in 27 patients when they were undergoing abdominal angiography for liver tumors or gall bladder cancer. The patients included 11 cases of liver cirrhosis and eight of chronic hepatitis. Pharmacological stimulation was done by infusion of 10 microg/Kg of nicardipine hydrochloride into the superior mesenteric artery through an angiographic catheter. We examined the correlation between stimulated or non-stimulated portal flow and biochemical liver function tests. RESULTS: Correlation coefficients and their corresponding p values between non-stimulated portal flow and the indocyanine green residual rate at 15 min after injection (ICG R15), serum albumin (ALB), total bilirubin (TB), cholinesterase (CHE), and hepaplastin test (HP) were--0.414 (0.056), 0.296 (0.134), -0.570 (0.002), 0.289 (0.153), and 0.321 (0.126), respectively, whereas those between stimulated portal flow and ICG R15, ALB, TB, CHE, and HP were--0.561 (0.007), 0.411 (0.033), -0.509 (0.007), 0.445 (0.023), and 0.494 (0.014), respectively. CONCLUSION: Stimulated portal flow showed better correlations with biochemical liver function tests than non-stimulated portal flow. It is suggested that stimulated portal flow measurement is more useful for the evaluation of liver function than non-stimulated portal flow measurement.
Aged↗
Tomographic evaluation of TMJ loading affected by occlusal pivots.
PURPOSE: The purpose of this study was to clarify the direction and magnitude of condyle displacement during clenching with occlusal pivots. Temporomandibular joint (TMJ) loading and flexibility and the clinical significance of orthopedic appliance therapy are also discussed. MATERIALS AND METHODS: Participants were 16 volunteers with a mean age of 25.8 years. Maxillary and mandibular flat occlusal devices were fabricated. TMJ tomogram series were taken first with tripod support and then with maxillary clenched anterior pivot support and/or unilateral posterior pivot support. Condyle positions on the TMJ tomograms were analyzed using the digital subtraction technique. RESULTS: When clenching with the anterior pivot, the anterior reference point (A) on the mandibular condyle was translated 0.1 mm posteriorly (P > 0.05) and 0.2 mm superiorly (P < 0.01) from the tripod-support reference point. In the case of the ipsilateral posterior pivot, point A was rotated 1.2 degrees (P < 0.01) and was translated 0.4 mm (P < 0.01) posteriorly and 0.18 mm superiorly (P > 0.05). CONCLUSION: Condyle displacement during clenching with the anterior and posterior unilateral pivot was found, which supports previous findings. However, the direction and magnitude of the displacement differed from those of previous studies using jaw-tracking devices, and individual values differed greatly among subjects.
Adult↗