Evaluation of Myelotoxicity in Dietary Restricted Rats

The purpose of this study was to clarify the effect of decreased food consumption on evaluation of myelotoxicity in routine general toxicity studies. Male rats were divided into the following 7 groups: 12, 15, and 18 mg/kg 5-fluorouracil (5-FU) treatment groups (FU12, FU15 and FU18); dietary restriction groups (R12, R15 and R18 receiving the same amount of food as the rats in the FU12, FU15 and FU18 groups, respectively); and a nontreated control group (NT). We compared the changes in body weight, hematology and the results of cytological analyses of bone marrow and histopathology among the groups after administration and recovery periods of 14 and 7 days, respectively. At the end of the administration period, the FU15 and FU18 groups showed decreases in many hematologic and bone marrow parameters that were all similar to those in the corresponding dietary restriction groups (R15 and R18). A granulocyte abnormality (polyploidy: frequency of 1% or less) was also observed in all 5-FU treated groups. At the end of the recovery period, increases in the reticulocyte and platelet counts and extramedullary hematopoiesis of the spleen were observed in the 5-FU treated groups. These results indicate that the results of general toxicity studies in rats should be evaluated in consideration of dietary restriction effects when food consumption is decreased at about 30-40% or more. Careful morphological observation of hemocytes would be helpful in distinguishing the effect of a drug from that of dietary restriction in relation to hematological and bone marrow parameters. Performance of a recovery test to determine the reactive response of hematopoiesis is also recommended

Importance of Starting Age for Myelotoxicity Study in Dietary Restricted Rats

The aim of this study was to prove our hypothesis that adult rats with lowering of body weight gain, rats at 12 weeks of age as an example, are suitable for evaluation of myelotoxicity. Age-related differences between young rats (6-week-old study) and adult rats (12-week-old study) were analyzed in hematological examination values. The data of the young rats were reprinted from our previous report (Miyata et al., 2009) since our hypothesis was verified by comparison with that previous report. Several experimental groups were defined for the 12-week-old study as well as for the 6-week-old study; these included 5-fluorouracil (5-FU) treated groups receiving 12, 15 and 18 mg/kg/day (FU12, FU15 and FU18), pair-feeding groups (R12, R15 and R18 receiving the same amount of food as in the FU12, FU15 and FU18 groups, respectively) and a nontreated control group. Numerous hematologic and bone marrow parameters in the 5-FU treated groups were comparable to those in the corresponding pair-feeding groups in both age studies. Generally, the influences of undernutrition were more apparent in the young rats than in the adult rats. Histopathological examinations showed a decrease in hematopoiesis in the bone marrow in the 5-FU treated and pair-feeding groups. No apparent differences were observed in the decreased hematopoiesis between the 5-FU treated and pair-feeding groups in the 6-week-old study, but a difference between these groups was noted in the 12-week-old study; decreased hematopoiesis was more frequently noted in the 5-FU treated groups. These facts suggest that adult rats are more suitable than young rats for evaluation of 5-FU-induced myelotoxicity

Evaluation of Short-term Myelotoxicity Study in Dietary Reduced Rats

This study attempted to prove our hypothesis that a short-term toxicity study, using a 4-day dosing regimen as an example, is suitable for evaluating myelotoxicity in rats. We compared the hematological, bone marrow cytological and histopathological results of 5-fluorouracil (5-FU) treated and pair-feeding groups after a 4-day administration period. Several experimental groups were defined for this 4-day study as well as for our previously reported 14-day study (Miyata et al., 2009); these included 5-FU treated groups receiving 12, 15 and 18 mg/kg/day (FU12, FU15 and FU18), pair-feeding groups (R12, R15 and R18 receiving the same amount of food as the FU12, FU15 and FU18 groups, respectively) and a nontreated control group. Although severe reductions in body weight gain and food consumption were reported in the 14-day study, only slight reductions were observed in the 4-day study. In the 4-day study, a decrease in blood reticulocytes and a decreasing trend of marrow erythroid cells were only observed in the FU18 group, and no effects were observed in the pair-feeding groups. The erythroblastic changes observed in this 4-day study were thought to reflect the direct influence of 5-FU administration. Since concerns regarding the influence of secondary changes related to undernutrition were minimized in the 4-day study, it was thought to clarify the direct influence of 5-FU administration on erythroblastic cells. Thus, a 4-day study protocol might be helpful for distinguishing secondary changes related to undernutrition

Endoscopic thoracic sympathicotomy for Raynaud's phenomenon

AbstractPurpose: For many years, thoracic sympathectomy via open surgery was not used to treat Raynaud's phenomenon because of the invasiveness of this procedure and the poor long-term outcomes associated with it. However, with the introduction of endoscopic surgery, thoracic sympathectomy (or sympathicotomy) has been performed by some surgeons as a less invasive surgical option for patients with Raynaud's phenomenon. The less invasive procedure has the possibility of emphasizing merits of sympathectomy. The purpose of this study was to reevaluate the efficacy of sympathicotomy for Raynaud's phenomenon with endoscopic technique and its range of applicability. Methods: Between December 1992 and August 2001, endoscopic thoracic sympathicotomy (ETS) was performed in 28 patients with Raynaud's phenomenon (of a total of 502 patients with autonomic disorders who underwent ETS) at National Kanazawa Hospital. We considered indications for surgical treatment of Raynaud's phenomenon to include severe chronic symptoms or nonhealing digital ulceration refractory to intensive medical therapy. All patients were mailed a self-assessment questionnaire after surgery to determine the immediate and long-term results of the procedure. Data from both initial and long-term follow-up examinations were obtained. Results: Fifty-four ETS procedures were performed in 28 patients. No operative mortality was seen, and no occurrence of major complications necessitated open surgery. Initial resolution or improvement of symptoms was achieved in 26 of 28 patients (92.9%). However, later in the postoperative period, symptoms recurred in 23 of 28 patients (82.1%), although no recurrence of digital ulceration was seen throughout our observation. At the final follow-up examination (median follow-up period, 62.5 months), 25 patients (89.3%) reported overall improvement of the frequency and severity of their symptoms. Conclusion: Despite the high rate of recurrence, ETS clearly produced a high rate of initial relief. ETS did indeed promote healing of digital ulcers, and the procedure shows potential for reducing the severity of refractory symptoms. We consider ETS to be the method of choice for treatment of severe or refractory Raynaud's phenomenon, and especially for Raynaud's involving digital ulcer, because of its safety and efficacy. (J Vasc Surg 2002;36:57-61.

中性子捕捉療法における硼素化合物の薬物動態と腫瘍内移行

BNCT (boron neutron capture therapy) is based on the intracellular nuclear reaction that occurs between the boron-10 nucleus and a thermal neutron. Upon capture, the boron nucleus disintegrates into highly energetic alpha (4He) and lithium (7Li) particles. Because of the short pathways of these heavy particles and 10B accumulation in target tissues, the great potential advantage of BNCT is a selective tumor destruction without significant damage to normal brain tissue. Since 1968, we have treated 146 patients with malignant brain tumors by BNCT. The 5-year survival rate of malignant glioma was 29%. Important factors which improve the results of BNCT are boron concentration in the tumor and neutron sauces. We have used BSH (mercaptoundecahydrododecaborate, Na2B12H11SH) as a boron compound in all patients. BSH is characterized by the absence of toxic side effects and represents the only promising boron carrier applied for the therapy of malignant glioma. However, data on the biodistribution and pharmacokinetics of BSH are few and lack in stadardization. We retrospectively analyzed the biodistribution and pharmacokinetics of BSH in 146 patients treated by BNCT from 1968 to 1994. 1) Pharmacokinetic parameters and standard expression of blood boron content of BSH were calculated by the two-compartment model theory in intra-arterial and intra-venous infusion groups. The parameters revealed that BSH could move easily from blood to the peripheral organs with sustained retention and that elimination was very slow. (CL=3.43L/hr, Vss=181.8 L, MRT=53.0 hrs) 2) Pharmacokinetic parameters were calculated in each case. The patients were divided into two groups : the intra-arterial (56 patients) and the intra-venous (31 patients) groups. BSH was administered into cervical brain arteries in the intra-arterial group, and peripheral veins in the intra-venous group. BSH in the intra-arterial infusion group was found to move from blood into the peripheral organs more easily than that of the intravenous infusion group. 3) In patients with malignant glioma, the average values of boron concentration in the tumor and the tumor to blood ratio (T /B ratio) after intra-arterial infusion (44 patients with 53 samples) were 26.8 μg/g and 1. 77 respectively. On the other hand, after intravenous infusion (13 patients with 13 samples) the values were 20. 9 μg/ g and 1. 33 respectively. There were no statistical significant differences in the average values of boron concentration in the tumor and the T /B ratio between the intra-arterial and the intravenous groups. 4) Both the average values of boron concentration in the tumor and the T /B ratio in patients with malignant glioma showed about 2. 7 and 3. 0 times higher that those of low grade glioma. However, there were no statistical significant differences in the tumoral boron concentration and the T /B ratio between cases of anaplastic astrocytoma and glioblastoma

Blood concentrations of small extracellular vesicles are determined by a balance between abundant secretion and rapid clearance

Small extracellular vesicles (sEVs) are important mediators of cell–cell communication with respect to diverse physiological processes. To further understand their physiological roles, understanding blood sEV homoeostasis in a quantitative manner is desired. In this study, we propose novel kinetic approaches to estimate the secretion and clearance of mouse plasma–derived sEVs (MP-sEVs) based on the hypothesis that blood sEV concentrations are determined by a balance between the secretion and clearance of sEVs. Using our specific and sensitive sEV labelling technology, we succeeded in analysing MP-sEV clearance from the blood after intravenous administration into mice. This revealed the rapid disappearance of MP-sEVs with a half-life of approximately 7 min. Moreover, the plasma sEV secretion rate, which is presently impossible to directly evaluate, was calculated as 18 μg/min in mice based on pharmacokinetic (PK) analysis. Next, macrophage-depleted mice were prepared as a model of disrupted sEV homoeostasis with retarded sEV clearance. MP-sEV concentrations were increased in macrophage-depleted mice, which probably reflected a shift in the balance of secretion and clearance. Moreover, the increased MP-sEV concentration in macrophage-depleted mice was successfully simulated using calculated clearance rate constant, secretion rate constant and volume of distribution, suggesting the validity of our PK approaches. These results demonstrate that blood sEV concentration homoeostasis can be explained by the dynamics of rapid secretion/clearance

ADAMTS13によるvon Willebrand因子の切断増加は、本態性血小板血症患者における後天性von Willebrand症候群の発症に強く寄与する。

Background: Patients with essential thrombocythemia (ET) often experience bleeding associated with acquired von Willebrand syndrome (AVWS) when the platelet count is markedly increased. Objective: We investigated whether von Willebrand factor (VWF) degradation is enhanced in patients with ET. Methods: Seventy patients with ET underwent VWF multimer (VWFM) analysis and measurement of VWF-related parameters. We calculated the VWFM index, defined as the ratio of intensities of a patient's molecular weight-categorized VWFMs, and those of a healthy subject's, using densitometric analysis. VWF degradation product (DP) was measured via ELISA using a monoclonal antibody that specifically recognizes Y1605 at the C-terminal boundary, which is exposed following ADAMTS13-mediated cleavage of the Y1605-M1606 bond of the VWF A2 domain. Results: Patients with higher platelet counts had a significantly reduced high molecular weight (HMW)-VWFM index and an increased VWF-DP: VWF antigen (Ag) ratio compared to those with lower platelet counts. On multivariate analysis, the VWF-DP/ VWF:Ag ratio was an independent predictor of the HMW-VWFM index. Patients who underwent cytoreductive therapy had a significantly higher HMW-VWFM index and lower VWF-DP/ VWF:Ag ratio than those who did not. Among individual patients, there was also a significant increase in the HMW-VWFM index and a decrease in the VWF-DP/ VWF:Ag ratio after cytoreductive therapy compared to pre-therapy values. Conclusion: In patients with ET, an increased platelet count is associated with enhanced cleavage of VWF at the Y1605-M1606 bond, primarily by ADAMTS13, leading to AVWS. Cytoreductive therapy reduces the platelet count, prevents excessive VWF cleavage, and improves VWFM distributions.博士（医学）・甲第881号・令和5年3月15

Effects of Sultopride and Sulpiride on Serum Prolactin Level in Schizophrenia.

Sultopride or sulpiride was administered to 26 schizophrenic patients. In the male patients, there was a significant correlation between serum concentrations of sultopride and sulpiride and prolactin response. In the female patients, there was no significant correlation between them. In sultopride treatment, prolaction response was suggested to be predictive of a good therapeutic response