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Biomedical subjects

T Sakamoto

Publications and source records attributed to T Sakamoto.

At least 325 records · Page 18Linked to original sources
PubMed1999

In vitro reconstitution of the tracheal epithelium.

We have developed a unique in vitro reconstitution system for tracheal epithelia of guinea pigs. In the system, a human amnion membrane was used as a basement membrane and the tracheal epithelial cells were cultured on the epithelial side of the membrane. Three weeks later, the tracheal fibroblasts were co-cultured on the serosal side of the amnion membrane and the culturing was continued for an additional 10 d. The morphology of the cultured epithelial cells consisted of a pseudostratified columnar ciliated epithelium from cuboidal ciliated epithelium during the last 10 d of the culture period. Epithelial cells included both goblet-like and basal cells. In addition, the frequency of each type of differentiated cells was almost identical to that of in vivo tracheas. Interestingly, the same results were obtained when the conditioned medium of the tracheal fibroblasts was used instead of the fibroblasts themselves. These results suggest that epithelial-mesenchymal interaction is likely involved in growth and differentiation of epithelial cells in vivo in a soluble factor(s)-mediated manner. As well as the epithelial cells, the fibroblasts also formed a multilayer during the last 10 d of co-culturing. This indicates that in vitro reconstitution of tracheal epithelia is achieved without addition of any exogenous growth or differentiation factors. The reconstitution system is shown to be useful for investigating the cellular and molecular interaction of epithelial and mesenchymal cells. Possible applications of the culture system and possible factors involved in growth and differentiation of epithelial cells are discussed.

Amnion↗
PubMed1999

Brain stem neural mechanisms for vocalization in decerebrate cats.

In order to characterize the brain stem circuitry that produces vocalization, the activities of brain stem respiratory neurons were recorded extracellularly during vocalization induced by electrical stimulation of the periaqueductal gray in decerebrate cats. After the onset of stimulation, the respiratory rhythm ceases, and a preparatory inspiration is induced. Following this initial inspiration, vocalization characterized by increased activities of the intrinsic laryngeal adductor and the major expiratory muscles is induced. During vocalization, most of the dorsal respiratory group inspiratory neurons increase their firing rates in phase with an increase of diaphragm activity. Inspiratory neurons with a continuous discharge pattern in the rostral ventral respiratory group increase their firing rates to augment intrinsic laryngeal abductor motoneurons and bulbospinal inspiratory neurons in the dorsal respiratory group. On the other hand, most of the bulbospinal augmenting expiratory neurons in the Bötzinger complex cease firing just after the onset of periaqueductal gray stimulation for the remainder of the stimulation period. These results indicate that at least some part of the coordinated activations of intrinsic laryngeal and respiratory muscles during vocalization are mediated via the central respiratory neurons that produce breathing.

Animals↗
PubMed1999

Prognostic value of serum hepatocyte growth factor in patients with acute coronary syndromes.

The present study examined whether or not hepatocyte growth factor (HGF), an endothelium-specific growth factor that stimulates regeneration of the endothelium, is increased or has a prognostic significance in patients with acute coronary syndromes. HGF was measured in 106 patients with coronary artery disease (20 stable effort angina, 12 unstable angina without adverse events, 24 unstable angina with adverse events and 50 acute myocardial infarction) on admission and 21 normal volunteers. The measurements in all patients were recorded before administration of heparin, and in acute myocardial infarction patients they were recorded from days 2 to 6 after heparin discontinuation on day 1. HGF levels (ng/ml) were 0.30+/-0.06 for the controls, 0.31+/-0.08 for stable effort angina patients, 0.31+/-0.08 for unstable angina patients without adverse events, 0.40+/-0.20 for unstable angina patients with adverse events and in acute myocardial infarction patients they were 0.45+/-0.18 on day 0, 0.57+/-0.45 on day 2, 0.50+/-0.35 on day 3, 0.48+/-0.32 on day 4, 0.44+/-0.20 on day 5, and 0.38+/-0.14 on day 6. HGF plays a crucial role in the restoration of injured endothelial cells and is a predictor of adverse events in patients with acute coronary syndromes.

Acute Disease↗
PubMed1999

Regional left ventricular dysfunction in a patient with severe prolonged anemia.

A 47-year-old woman with severe prolonged anemia developed heart failure. After treatment of the heart failure and anemia, she showed regional dysfunction of the left ventricular wall and myocardial fatty acid metabolism was disturbed in these sites. Coronary arteriography showed normal images. It took about 4 months to recover both left ventricular wall motion and fatty acid metabolism. Prolonged decrease of oxygen supply to the myocardium, which is caused by severe prolonged anemia, seemed to affect the myocardial function in this case, which could be another model of anemia-related myocardial dysfunction.

Anemia↗
PubMed1999

Is the primitive regulation of pituitary prolactin (tPRL177 and tPRL188) secretion and gene expression in the euryhaline tilapia (Oreochromis mossambicus) hypothalamic or environmental?

We examined the effects of environmental salinity on circulating levels of the two prolactins (tPRL177 and tPRL188) and levels of pituitary tPRL177 and tPRL188 mRNA in the euryhaline tilapia, Oreochromis mossambicus. Fish were sham-operated or hypophysectomized and the rostral pars distalis (RPD) autotransplanted onto the optic nerve. Following post-operative recovery in (1/4) seawater, tilapia were transferred to fresh water (FW), (1/4) seawater (SW) or SW. Serum tPRL177 and tPRL188 levels in sham-operated and RPD-autotransplanted fish were highest in FW and decreased as salinity was increased. tPRL177 and tPRL188 mRNA levels in RPD implants as well as in pituitaries from the sham-operated fish were also highest in FW and decreased with increasing salinity. Serum osmolality increased with salinity, with the highest levels occurring in the seawater groups. We conclude that some plasma factor (probably plasma osmolality), in the absence of hypothalamic innervation, exerts a direct regulatory action on prolactin release and gene expression in the pituitary of O. mossambicus. This regulation is in accord with the actions of the two prolactins in the freshwater osmoregulation of the tilapia.

Analysis of Variance↗
PubMed1999

Heterogeneous reactivity of murine epidermal Langerhans cells after application of FITC: a histochemical evaluation.

To elucidate the detailed kinetics of epidermal Langerhans cells after topical contact sensitizer stimulation, we examined ATPase or Ia positive epidermal cells of BALB/c mice in a time-spaced manner after the topical application of fluorescein isothiocyanate (FITC). We also performed double labeling of Langerhans cells in epidermal sheets with ATPase activity and Ia antigen or costimulatory molecules (B7-1 and B7-2) after the same stimulation. Observations showed that the density of ATPase positive cells and Ia positive cells decreased following a different time course; the former reached a nadir (77.4% of control) at 4 h but the latter reached a minimum (82.8% of control) at 16 h after the application of FITC. A double labeling technique revealed an increase in Ia single positive cells at 4 h as opposed to that of ATPase single positive cells at 16 h after application. Both costimulatory molecules were expressed on the dendritic processes of many Langerhans cells as a dotty pattern at 4 h after application; B7 positive and ATPase negative areas were observed at this time. On electron microscopic observation, a few activated Langerhans cells found in the dermis at 4 h after application had distinctive profiles compared with residual Langerhans cells in the epidermis. These findings suggest that there is a heterogeneity of reactivity to FITC in epidermal Langerhans cells, and that only a small portion of them migrates from the epidermis during sensitization. The findings also indicate the importance of the interaction between the Langerhans cell and its surrounding microenvironment in the epidermis for its activation. In addition, the results indicate that the enzymatic and the phenotypic markers do not definitively reflect the presence (or absence) of Langerhans cells.

Adenosine Triphosphatases↗
PubMed1999

Vasospastic angina likely related to cisplatin-containing chemotherapy and thoracic irradiation for lung cancer.

Vasospastic angina is rarely observed during cancer treatment. The present report describes two males with lung cancer, aged 73 and 61, who developed vasospastic angina during combination treatment of cisplatin-containing chemotherapy and thoracic irradiation. As both patients have smoked and their ages are typical for patients with coronary artery disease, such events may be incidental. However, oncologists should be aware of the possible development of myocardial ischemia during or following administration of antineoplastic agents, especially in elderly patients with pre-existing coronary risk factors or a history of thoracic radiotherapy.

Adenocarcinoma↗
PubMed1999

An electromyogram study on mandibular movement in unilateral cleft lip and palate patients before and after orthodontic treatment.

The purpose of this study is to investigate masticatory muscle function in subjects with unilateral cleft lip and palate compared with normal occlusion and the extents of improvement before and after orthodontic treatment. Subjects were twenty pretreatment patients, thirty posttreatment patients and ten controls. Electromyograms were recorded from their masticatory muscles during masticatory movement and tapping movement. Reduction of duration/stroke ratio (D/S) was observed in electromyograms obtained during masticatory movement after orthodontic treatment. The reduction was especially notable in the masseter muscle. In spite of a significant reduction in coefficient of variation (CV) values, a significant difference between the posttreatment group and the control group indicated some persisting irregularity in masticatory movement. Electromyograms taken during tapping movement showed no change in latency in the posttreatment group, but duration of the silent period (SP) was shortened and SP appearance increased. The findings outlined above reveal electromyographically clear improvements in masticatory muscle functions and jaw reflex mechanisms after orthodontic treatment. Nevertheless, parameters for subjects with cleft lip and palate still differed from those for controls with normal occlusion. The influence of plastic surgery in subjects with the defects discussed here causes maxillary retrusion, which in turn results in skeletal malocclusion. Orthodontic treatment should be designed to compensate this dentally and alveolarly. This design and the need to improve masticatory functions would contribute to eliminate the extreme difficulty of the therapeutic process.

Adolescent↗
PubMed1999

Saline-jet aspiration thrombectomy catheter. Clinical results in patients with venous thrombosis.

PURPOSE: To evaluate hydraulic thrombectomy using a saline-jet aspiration thrombectomy catheter in the treatment of venous thrombosis. MATERIAL AND METHODS: Ten patients underwent 12 hydraulic thrombectomy procedures using 2.7 or 4.0 mm catheters. The site of the thrombus was either central, peripheral or in portal veins. The age of the thrombi was between 2 and 60 days (mean 19.7 days). The efficacy of hydraulic thrombectomy was evaluated based on the aspirated thrombus ratio (ATR), i.e. the volume of the thrombus aspirated divided by the volume of the thrombus before thrombectomy. ATR was estimated by comparing the angiograms of the lesion before and after thrombectomy. RESULTS: Soft thrombi were usually rapidly removed. ATR was >2/3 in 3, 2/3-1/3 in 2, 1/3-0 in 4, and 0 in 1 patient. The activation time of the injector was 23-224 s (mean 102 s) and the volume of aspirated blood was 30-680 ml (mean 250 ml). Compensatory infusion of saline was performed for blood loss, and 400 ml of packed red blood cells was transfused in 1 patient. No complications of the hydraulic thrombectomy were observed. Thrombolysis or additional treatment were performed in 9 patients. CONCLUSION: Hydraulic thrombectomy using this catheter can contribute to the treatment of venous thrombosis.

Equipment Design↗
PubMed1999

Efficacy of initial controlled perfusion pressure for ischemia-reperfusion injury in a 24-hour preserved lung.

In lung transplantation, the safety period of the ischemic time of the graft is within 6 hours. Because of the problem of donor shortage, it is essential to extend the safety period of the preservation time of the donor lung. However, the longer the preservation time is, the more severe is the resulting ischemia-reperfusion injury. This study was designed to evaluate the efficacy of initial controlled perfusion pressure in the reduction of ischemia-reperfusion injury in a 24-hour preserved lung. Japanese white rabbit lungs were flushed with a low-potassium dextran solution (4C, 500 ml) after injection of prostaglandin E1 (20 microgram, bolus via PA) and submersed in the same solution for 24 hours at 4C. After preservation, the left lung was reperfused using an extracorporeal lung perfusion model which comprised of a closed circuit combined with a membrane deoxygenator. Assessment of lung function included gas analysis of influent and effluent blood and mean pulmonary artery perfusion pressure. Then the lung wet/dry weight ratio was calculated. In group I of the control group (n=6), the left lung was reperfused immediately following flushing (without preservation) at a flow rate of 50 ml/min for 60 minutes. In groups II and III, grafts were stored for 24 hours. In group II, grafts (n=6) were reperfused at a flow rate of 50 ml/min for 60 minutes. In group III (n =6), the flow rate was controlled by maintaining the perfusion pressure below 30 mmHg during the initial 5 minutes and was increased to 50 ml/min for the subsequent 60 minutes. In group II, the mean pulmonary artery pressure during perfusion increased rapidly, and oxygenation deteriorated. All grafts developed pulmonary edema within 12 minutes after reperfusion. Examination of the specimen revealed that the peripheral lung was not perfused. In group III, the mean pulmonary artery perfusion pressure was maintained below 30 mmHg, and oxygenation was preserved sufficiently throughout the experiment (delta PO2 > 100 mmHg) with no significant difference from control values. In conclusion, ischemia-reperfusion injury of the 24-hour preserved lung was attenuated prominently by controlling initial perfusion pressure for 5 minutes.

Analysis of Variance↗
PubMed1999

[Effect of deliberate mild hypothermia on the incidence of surgical-wound infection and duration of hospitalization in neurosurgical patients].

We investigated the effect of mild hypothermia on the incidence of surgical-wound infection and duration of hospitalization, retrospectively. We randomly assigned 173 patients undergoing intracranial operation to mild hypothermic group (group H) of 122 patients or normothermic group (group N) of 51 patients. A water blanket and a convective device blanket were used for thermal control in the both groups. The temperature at the tympanic membrane was adjusted to 34.5 degrees C in group H and 36.0 degrees C in group N. Surgical-wound infection was found in 4 of 122 patients (3.3%) of group H but in none of 51 patients (0%) of group N. The duration of hospitalization was 36.0 +/- 25.5 days in group H and 40.2 +/- 36.9 days in group N. There were no statistical differences of the incidence of surgical-wound infection and duration of hospitalization between the two groups. However, the duration to suture removal was significantly longer in group H than in group N (8.3 +/- 1.6 vs 7.8 +/- 0.8 days). Although the effects of deliberate mild hypothermia for neurosurgery on the incidence of surgical-wound infection and duration of hospitalization were little, it may affect the recovery process of such patients.

Adult↗
PubMed1999

[Ventricular fibrillation during mild hypothermic therapy in a patient undergoing neurosurgery].

A 35 year old male for mild hypothermic therapy for neurosurgery, developed ventricular fibrillation. Total resection of cerebral arteriovenous malformation was performed under mild hypothermic therapy, with the target core temperature of 33 degrees C. Intraoperatively cooling rate was low and a reduction of peripheral temperature associated with metabolic acidosis was noted. After the conclusion of the operation and during transferring the patient to an intensive care unit, multiple ventricular premature beats were noted. Thereafter, ventricular tachycardia developed proceeding ventricular fibrillation. We suggest that careful management of thermal and cardiovascular systems is required to prevent adverse events during mild hypothermic therapy.

Adult↗
PubMed1999

[Development and evaluation of parent-related quality of life questionnaires for asthmatic children and their parents or caregivers--evaluation of treatment process with sustained-release theophylline dry syrup].

A quality of life (QOL) questionnaire for asthmatic children and their parents or caregivers was shown to exhibit reliability, factorial validity and possibility for application study in our previous report. The aim of this study was to examine longitudinal study of the questionnaires, including changes of QOL, responsibility to asthmatic symptoms, consistency with conventional asthma scores and clinical outcomes during treatment with theophylline dry syrup for about three months. Overall QOL scores increased significantly (p < 0.01) with improvement in clinical outcomes. Longitudinal changes of QOL were compared with differences (after-before) and changes of ratio [(after-before/before)] in QOL by correlation analysis between differences of asthma scores. Changes of ratio in QOL were reflected by the clinical outcomes. Results of investigation of correlation between differences in asthma scores and changes of ratio in QOL domains were considered as follows. Physical domain was correlated with asthma symptoms, given the moderate correlation (rho = 0.497). Social and family domains showed fair correlation (rho = 0.382 - 0.384 respectively), both domains were hard to correlate with differences in asthma scores. Emotional domain showed fair correlation (rho = 0.264) for reflecting family's emotion. Poor correlation (rho = 0.071) was observed in individual growth domain which was necessary to evaluate for longer term. Changes of ratio in QOL responded significantly (p < 0.01) to improved and worst-unchanged groups which were categorized by the differences in asthma scores. In conclusion, QOL questionnaires showed longitudinal validity for clinical outcomes and responsibility to asthmatic symptoms. It yields useful information for understanding how asthmatic symptoms affect parents or caregivers and investigating what treatments should be prescribed for the patients with asthma.

Administration, Oral↗
PubMed1999

[Development of parent-rated quality of life questionnaire for asthmatic children and their parents or caregivers--reliability and factorial validity].

We developed a questionnaire form on quality of life (QOL) designed for data entry by parents or caregivers of asthmatic children, which consisted of five domains: physical, social, family, emotional, and individual growth domains. QOL scores were determined according to the five-point scale by which one point was given for maximal impairment and five points for no impairment. The form included 23 questions for children under the age of four and 31 questions for children over the age of four. This study examined reproducibility, reliability, and factorial validity of the form. The numbers of asthmatic children, whose symptoms of asthma attacks had been stable for the 2 weeks before this study, were as follows: eight children under the age of four; and 26 children over the age of four. The intra-class correlation coefficients for these two categories of children were 0.879 and 0.793, respectively; therefore, reproducibility was shown. The values of Cronbach's alfa for the total scores of QOL were 0.6329 to 0.8829 in 102 asthmatic children, 40 healthy children, and 12 non-asthmatic children, e.g., children affected by cold. Therefore, internal consistency was shown. The rank-orders of the replies to the questions associated with the physical, social, family, and emotional domains other than the individual growth domain decreased significantly (p < 0.05) in asthmatic children as compared with healthy or non-asthmatic children. Factor analysis confirmed the five established domains and each facets therein at the cumulative variance of 60% or higher. In conclusion, this questionnaire form on QOL of asthmatic children was considered to have reproducibility, constitutional reliability, and factorial validity, to be applicable at the time of medication, and to be useful in investigating approaches for the management of bronchial asthma and the targeting of treatment.

Asthma↗