Biomedical subjects
Publications and source records attributed to M Hirata.
Explore the source record for details and available documents.
We treated pregnant rats with 1 microg/kg body weight/day 1,2,3,4,6,7-hexachlorinated naphthalene (1,2,3,4,6,7-HxCN) on days 14-16 of gestation and examined the effects on the reproductive systems of their male offspring at various phases of sexual maturation. Sperm count in the cauda epididymidis did not change in 1,2,3,4,6, 7-HxCN-treated rats on postnatal day 89, the age of sexual maturity, but the sperm count in the cauda epididymidis did increase to approximately 180% of the control value on postnatal day 62. In addition, homogenization-resistant testicular spermatids increased to approximately 160% of the control value on postnatal day 48, and the percent of postmeiotic tubules increased to approximately 190% of the control value on postnatal day 31 in this group. These results indicate that the onset of spermatogenesis was accelerated in the 1,2,3,4,6,7-HxCN rats. Serum concentrations of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) had already reached the maximum level on postnatal day 31 in the 1,2,3,4,6, 7-HxCN group, suggesting that the onset of LH and FSH secretions from the pituitary gland was also accelerated and that this endocrine disruption was the cause of early onset of spermatogenesis in this group. In the fat of 1,2,3,4,6,7-HxCN-treated dams, 5.75+/-2.81 ppb 1,2,3,4,6,7-HxCN was detected when offspring were weaned. This concentration was 5-10 times higher than that found in human adipose tissue.
The effects of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] and its analogue 22-oxa-1,25(OH)2D3 (22-oxacalcitriol) (OCT) on calcium and bone metabolism were examined in an animal model of hypercalcemia with continuous infusion of parathyroid hormone-related peptide (PTHrP), to determine whether active vitamin D could counteract the skeletal action of PTHrP in addition to its reported effect in suppressing the production of PTHrP in cancer cells. Parathyroid glands were removed from 8-week-old Sprague-Dawley rats to eliminate the confounding effects of endogenous PTH. Animals were then continuously infused with human PTHrP(1-34) at a constant rate via osmotic minipumps for 2 weeks, and at the same time treated orally or intravenously with OCT or 1,25(OH)2D3 four to nine times during the 2-week period. Under these conditions, OCT and, surprisingly, 1,25(OH)2D3 alleviated hypercalcemia in a dose-dependent manner. 1,25(OH)2D3 and OCT suppressed the urinary excretion of deoxypyridinoline, although they did not affect renal calcium handling, suggesting that the antihypercalcemic effect is attributable to the inhibition of bone resorption. These active vitamin D compounds also counteracted the effects of PTHrP at the proximal renal tubules, as reflected by a decrease in phosphate excretion. Histomorphometric analysis of bone revealed a dose-related decrease in parameters of bone resorption. These results suggest that 1,25(OH)2D3 as well as OCT has the potential to alleviate hypercalcemia, at least in part, through the inhibition of bone resorption in hypercalcemic rats with constant PTHrP levels. We propose that the main function of active vitamin D in high bone-turnover states is to inhibit bone resorption, and this may have important implications for the understanding of the role of active vitamin D in the treatment of metabolic bone diseases, such as osteoporosis.
In order to clarify the actual condition of occupational health management for hazardous and musculo-skeletally stressful work factors in small-scale enterprises (SSEs) in Japan, a questionnaire survey was conducted in an area near Osaka city. The hazardous work factors examined were dust, organic solvents, lead, specified chemical substances, anoxia, noise, hand-arm vibration, ionizing radiation, high and low temperatures, and high air pressure. The musculo-skeletally stressful work factors examined were VDT work, prolonged standing, unnatural postures, handling of heavy weights, and stress on neck, shoulders and arms. The number of SSEs that replied to the questionnaire was 765 (recovery rate: 69.3%). Enterprises with noise, dust, hand-arm vibration and organic solvents numbered 14.0%, 10.7%, 6.9% and 6.4%, respectively, and those with other hazardous factors numbered less than 3%. Special medical examinations and working environment measurements for hazardous factors were conducted in 0.0% to 26.7% and 0.0% to 13.3%, respectively, of the enterprises. Working environment controls were conducted in 0.0% to 40.2%. Enterprises with prolonged standing and VDT work, were 42.0% and 35.8%, whereas those with other stressful factors were approximately 30%. Special medical examinations for musculo-skeletally stressful factors were conducted in 3.0% to 5.1% of the enterprises, and work controls were conducted in 20.4% to 25.3%. Non execution of the special medical examinations and working environment measurements were mainly due to "lack of knowledge of the law (19.7% and 30.2%)" and "lack of time to perform (16.0% and 23.3%)". Non execution of the controls for the hazardous work factors was due to "lack of knowledge as to how to control (9.0%)", "high costs (7.4%)", "lack of time to perform (6.4%)" and "absence of a suitable adviser (5.9%)". Non execution of the controls for stressful work factors was due to "lack of knowledge as to how to control (15.6%)" and "lack of time to perform (10.2%)". Consequently, as a result of the survey, it was suggested that it is necessary to enlighten the employers of SEEs as to the importance of occupational health controls. It is also necessary to propose low-cost, feasible control methods.
We describe a case of intramural gastric hematoma with hemorrhagic shock caused by the formation of a large hematoma. Computed tomographic and angiographic examinations confirmed the presence of active bleeding into the hematoma. Transcatheter arterial embolization (TAE) was performed for hemostasis. To our knowledge, although 21 cases of intramural gastric hematoma have been reported in the literature, this is apparently the first case treated by TAE. We conclude that TAE is a safe and effective treatment option for intramural gastric hematoma confirmed to be associated with active bleeding into the hematoma.
The aim of the present study was to investigate whether thermal perception threshold testing is a useful method that could replace pain threshold testing in the evaluation of small sensory nerve fiber injury in vibration-induced neuropathy. Vibration, pain, and thermal (warm and cold) perception thresholds were examined on both middle fingers of 50 patients with hand-arm vibration syndrome and 29 healthy controls of similar age. The patients were divided into three subgroups according to the Stockholm Workshop sensorineural scale. Thermal (warm and cold) thresholds as well as vibration and pain thresholds were significantly more deteriorated among the patients than in the controls. Among the patients, warm thresholds elevated and cold thresholds lowered according to the Stockholm Workshop scale. Thermal thresholds were significantly correlated with pain thresholds, and the sensitivity of the thermal threshold testing tended to be greater than that of the pain threshold testing. The present findings indicate that thermal threshold testing for warm and cold perception can be a useful substitute for pain threshold testing to examine small nerve fiber injury in vibration-induced neuropathy.
We report a case of Epstein-Barr virus (EBV)-associated lymphoproliferative disorder (LPD) which developed after chemotherapy for hemophagocytic lymphohistiocytosis (HLH), who had no history of immunodeficiency or familial X-linked LPD. In HLH, the presence of EBV in T-cells was confirmed by a combination of in situ hybridization (ISH) and immunostaining. Southern blot analysis using EBV-TR and immunoglobulin JH probes revealed oligoclonal proliferation of B-cells in each organ involved by abnormal B-lymphoid cells at autopsy. Combined ISH and immunostaining disclosed the presence of EBV in proliferating B-cells. Cytokine analysis during the period of T-cell activation in HLH revealed marked elevation of interferon (IFN) gamma, interleukin (IL)-10 and soluble IL-2 receptor (sIL-2R) and mild to moderate increases of tumor necrosis factor (TNF)-alpha were observed, while IFN gamma, IL-10 and sIL-2R were elevated initially during the HLH phase, which then decreased as LPD developed and B-cell proliferation predominated. Immunosuppressive chemotherapy for HLH may then have allowed latent EBV in B lymphocytes to induce transformation and oligoclonal proliferation of B-cells, finally resulting in LPD. Mechanisms of EBV-induced cell proliferation remain unclear, but alteration of various cytokines may be responsible for it.
The authors tested a modified motor cortex stimulation protocol for treatment of central and peripheral types of deafferentation pain. Four patients with thalamic pain and four with peripheral deafferentation pain were studied. Preoperative pharmacological tests of pain relief were performed using phentolamine, lidocaine, ketamine, thiopental, and placebo. In five patients we placed a 20- or 40-electrode grid in the subdural space to determine the best stimulation point for pain relief for a few weeks before definitive placement of a four-electrode array. In three patients, the four-electrode array was implanted in the interhemispheric fissure as a one-stage procedure to treat lower-extremity pain. In two patients with pain extending from the extremity to the trunk or hip, dual devices were implanted to drive two electrodes. Six of eight patients experienced pain reduction (two each with excellent, good, and fair relief) from motor cortex stimulation. No correlation was apparent between pharmacological test results and the effectiveness of motor cortex stimulation. Patients with peripheral deafferentation pain, including two with phantom-limb pain and two with brachial plexus injury, attained pain relief from motor cortex stimulation, with excellent results in two cases. Testing performed with a subdural multiple-electrode grid was helpful in locating the best stimulation point for pain relief. Motor cortex stimulation may be effective for treating peripheral as well as central deafferentation pain.
Toxic effects of gallium arsenide (GaAs), indium arsenide (InAs) and arsenic trioxide (As2O3) were studied in male Syrian golden hamsters. GaAs (7.7 mg/kg) and As2O3 (1.3 mg/kg) particles were instilled intratracheally twice a week a total of 16 times, while InAs (7.7 mg/kg) was instilled a total of 14 times. As a control, hamsters were treated with the vehicle, phosphate buffer solution. During the instillation period, the cumulative body weight gain of the InAs-, but not the GaAs- or As2O3-treated hamsters was suppressed significantly, when compared with the control group. Slight to severe inflammatory responses were observed in the lung for all treatment groups. The most severe inflammatory change, characterized by an accumulation of neutrophils and macrophages, exudation, thickness of the pleura and fibrotic proliferation was found in the InAs-treated hamsters. Extensive alveolar or bronchiolar cell hyperplasia with or without keratinizing squamous cell metaplasia was observed in almost all the InAs-treated hamsters. Furthermore, squamous cell metaplasia or squamous cell hyperplasia developed in some of the InAs-treated hamsters, but not in the GaAs- or As2O3-treated hamsters. Slight to mild lesions were found in the convoluted tubules of the kidney in both the GaAs and InAs groups. From the present study, the toxic potency of these particles was provisionally estimated to be in the following order: InAs > GaAs > As2O3, at the dosage level used in this study. Furthermore, there was evidence that InAs particles could induce pulmonary, renal or systemic toxicity, and as such, InAs particles may produce pulmonary precancerous change when instilled intratracheally into hamsters.
It is very important to establish a clinical testing system which is not only prompt, simple and accurate but also safe for the patients and medical staff in the operating room, emergency room and intensive care unit. In our institution an i-STAT portable blood gas analyser has been widely used for point of care testing in all the operating rooms. This clinical testing system has been upgraded by adding an i-STAT communication protocol to our online data management system. The analysed data transmitted by the i-STAT as an infrared signal is transformed to an electronic signal through the IR link and sent to the central data station (CDS) via RS232C. The data received by the CDS is then sent to the upper grade computer system where the data is recorded on the hard disk. One advantage of this system is that it is connected to the hospital computer system. Not only does this new system meet the need for accurate, safe, effective and economical laboratory testing, but also retrospective and multifactorial analysis of intraoperative events can be easily carried out. In the future this system can be applied to telemedicine through the Internet and contribute to the treatment of critically ill patients.
Explore the source record for details and available documents.
Epidemiologic evidences suggest that obstructive sleep apnea syndrome(OSAS) itself induces risk factors for cardiovascular diseases(= insulin resistance) independent of obesity. Our data suggest that moderate to severe OSA(AHI = > 20) is a contributing factor to the development of hyperinsulinemia, abnormal glucose metabolism and non-insulin-dependent diabetes mellitus(NIDDM) independent of aging, obesity and hereditary predisposition for DM in patients with OSAS. On the other hand, disagreement exists as to the incidence of OSAS in DM patients. Some authors reported that the incidence of OSAS was high among patients with DM, while others did not find such relationship. In these studies, the number of cases studied was small and, in addition, the selection of patients may have been biased. Future clinical research is needed to answer this issue.
In neoplastic disorder-related nephrotic syndrome, focal glomerulosclerosis (FGS) has been reported mainly in hematological disorders like minimal change nephrotic syndrome (MCNS) in association with presumed T lymphocyte dysfunction. The association of FGS with cancer or solid tumor is rare. We report a case of nephrotic syndrome due to FGS in a patient with undifferentiated adenocarcinoma of the cystic duct. Although the underlying mechanism is unclear, the development of FGS seemed to be related to the poor histological differentiation of the cancer in the possibility of production of an active peptide.
We examined the temporospatial pattern of naturally occurring apoptosis in chick embryos to five days of incubation (H.H. stages 1-25; Hamburger and Hamilton, 1951) using TUNEL labeling. The initial TUNEL-positive structure was the embryonic shield at stage 1. Apoptotic cells became ubiquitously present within embryos by stage 3, which is early in gastrulation. Until stage 6, TUNEL-positive cells were restricted to the headfold region. In embryos of stages 7-8, most cell death was localized at the most anterior neural plate. TUNEL-positive neural plate, notochord and somites appeared at stage 9. Otic and optic regions became TUNEL-positive at stage 11. The aggregation of cells from which the tail bud arises contains apoptotic cells from stage 11 onwards. At stage 16, scattered TUNEL-positive cells appeared in the branchial arches. Three streams of apoptotic neural crest cells in the cranial region became most clearly visible at stage 18. The secondary neural tube from which caudal structures develop contains apoptotic cells at stage 14. Apoptotic cells are present in the branchial arches and lateral body wall for extended periods, stages 16-25 and 25 respectively. At stages 24-25, intense positive regions of cell death were confined to the caudal regions of the arches, to limb and tail buds and to the lateral body wall, the latter in relation to body wall closure. The new findings in this study are discussed along with past studies to provide the temporospatial pattern of cell death during early chick development.
BACKGROUND: In living-related liver transplantation (LRLT) in small children, standard end-to-end portal vein (PV) anastomosis is usually difficult because of a inadequate total PV length, or because of a size mismatch between the graft and the recipient PV. In this report, we present our new portal venoplasty technique for the recipient PV. METHODS: After dissection of the recipient PV, the wall between the right and left branches of the PV is severed longitudinally as in the branch patch technique. The anterior and posterior edges of both branches are joined using running sutures, to form a longer and wider PV for anastomosis. RESULTS: This new portal venoplasty technique was used in 7 of 28 child cases, and gave good results without thrombosis or other complications. CONCLUSIONS: Our new portal venoplasty technique is useful in LRLT in small children when the recipient or graft PV is not long enough.
The pleckstrin homology (PH) domains of phospholipase C (PLC)-delta1 and a related catalytically inactive protein, p130, both bind inositol phosphates and inositol lipids. The binding to phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] by PLC-delta1 is proposed to be the critical interaction required for membrane localization to where the substrate resides; it is also required for the Ca(2+)-dependent activation of PLC-delta1 observed in the permeabilized cells. In the proximity of the PH domain, both PLC-delta1 and p130 possess the EF-hand domain, containing classical motifs implicated in calcium binding. Therefore, in the present study we examined whether the binding of the PH domain to PtdIns(4,5)P2 is regulated by changes in free Ca2+ concentration within the physiological range. A Ca2+ dependent increase in the binding to PtdIns(4,5)P2 was observed with a full-length PLC-delta1, while the isolated PH domain did not show any Ca2+ dependence. However, the connection of the EF-hand motifs to the PH domain restored the Ca2+ dependent increase in binding, even in the absence of the C2 domain. The p130 protein showed similar properties to PLC-delta1, and the EF-hand motifs were again required for the PH domain to exhibit a Ca2+ dependent increase in the binding to PtdIns(4,5)P2. The isolated PH domains from several other proteins which have been demonstrated to bind PtdIns(4,5)P2 showed no Ca2+ dependent enhancement of binding. However, when present within a chimera also containing PLC-delta1 EF-hand motifs, the Ca2+ dependent binding was again observed. These results suggest that the binding of Ca2+ to the EF-hand motifs can modulate binding to PtdIns(4,5)P2 mediated by the PH domain.
Antimicrobial peptides, named tachystatins A, B, and C, were identified from hemocytes of the horseshoe crab Tachypleus tridentatus. Tachystatins exhibited a broad spectrum of antimicrobial activity against Gram-negative and Gram-positive bacteria and fungi. Of these tachystatins, tachystatin C was most effective. Tachystatin A is homologous to tachystatin B, but tachystatin C has no significant sequence similarity to tachystatins A and B. Tachystatins A and B showed sequence similarity to omega-agatoxin-IVA of funnel web spider venom, a potent blocker of voltage-dependent calcium channels. However, they exhibited no blocking activity of the P-type calcium channel in rat Purkinje cells. Tachystatin C also showed sequence similarity to several insecticidal neurotoxins of spider venoms. Tachystatins A, B, and C bound significantly to chitin. A causal relationship was observed between chitin binding activity and antifungal activity. Tachystatins caused morphological changes against a budding yeast, and tachystatin C had a strong cell lysis activity. The septum between mother cell and bud, a chitin-rich region, was stained by fluorescence-labeled tachystatin C, suggesting that the primary recognizing substance on the cell wall is chitin. As horseshoe crab is a close relative of the spider, tachystatins and spider neurotoxins may have evolved from a common ancestral peptide, with adaptive functions.
We analyzed the DNA ploidy alterations after preoperative chemotherapy in 30 patients with non-metastatic osteosarcomas of the extremities. All of the patients received intensive chemotherapy with doxorubicin, cisplatin and methotrexate as well as wide tumor resection. DNA ploidy was determined by DNA cytofluorometry using isolated and smeared cells from biopsied and resected tumors after preoperative chemotherapy. The results showed that 12 diploid and nine non-diploid osteosarcomas did not change their ploidy pattern, but nine non-diploid tumors changed to a diploid pattern with the disappearance of the aneuploid cells. The nine patients with altered ploidy tumors had a better histologic response to chemotherapy and a better prognosis than the patients with non-altered tumors especially diploid tumors (P = 0.0138). Therefore, we conclude that a decrease in aneuploid cells after chemotherapy is closely correlated with a good prognosis in half of the cases of aneuploid osteosarcoma. These results also suggest that aneuploid cells are more chemosensitive than diploid cells in human osteosarcomas.