A study was conducted to investigate the mechanism of bone atrophy in various strains of inbred mice under the influence of tail-up suspension. Nine inbred strains of mice (NZB/N, NZW/N, AKR/N, Balb/C, C 57 BL, C 3 H/He, A/J, DBA, CBA/N) aged six weeks were used. Each strain was divided randomly into two groups, a suspension group (SG; n=5) and a control group (CG; n=5) . The suspension group were etherized and suspended with an elastic bandage. After one week, the tibiae were removed and their bone weights were measured using an electric balance (Metler; AE 240) . Their length was also measured with a vernier caliper. In all strains, body weight in the SG was significantly lower than that in the CG. From the bone weight and length in the CG, bone growth in the NZB/N, AKR/N, NZW/N and C3H/He strains was considered to be higher than in the other strains. On the other hand bone growth in the DBA, A/J, Balb/C, and CBA/N strains were lower than in the others. The absolute value of bone weight in the SG was significantly smaller than that in the CG in six strains (NZB/N, C 57 BL, A/J, NZW/N, C 3 H/He, Balb/C) . However in the DBA strain, the absolute value of bone weight in the SG was significantly higher than that in the CG.
From the results of this investigation we suggest that the mechanism of normal bone growth is not the same as the mechanism of bone atrophy induced by tail-up suspension.

We have examined the role of readmission of oxygen in the initiation of reperfusion-induced arrhythmias by separating readmission flow from readmission of oxygen on a temporal basis. Isolated rat hearts (n=12/group) were subjected to 10 minutes of global ischemia and reperfusion. In controls reperfused with aerobic perfusion medium, 100% of hearts developed ventricular tachycardia 1.48±0.78 seconds after reperfusion, and ventricular fibrillation occurred 13.47±2.91 seconds after reperfusion. Also in hearts reperfused with anoxic perfusion medium, 100% of hearts developed ventricular tachycardia 1.98±0.96 seconds after reperfusion, and ventricular fibrillation occurred 27.01±18.52 seconds after reperfusion. But the duration of the time from reperfusion to the onset of ventricular fibrillation were statistically differrent in these two groups (p<0.05). In conclusion anoxic reperfusion delayed ventricular fibrillation but prevent neither ventricular fibrillation nor ventricular tachycardia. This implies that oxygen-derived free radicals may play an important role in the initiation of reperfusion-induced arrhythmias, but are unneccessary for arrhythmogenesis.

We have established NICU (Neonatal Intensive Care Unit) in our hospital and have made efforts to improve the contents of medical treatment since 1976 in order to establish a regionalization of neonatal medical treatment.
Thus are main items of the improvement:
1. Completed the apparatuses and equipments needed in Intensive Care.
2. Promoted the communication with regional facilities of delivery so as to enable immature or stressed mature babies to be transported to our hospital at all hours.
3. Made Pediatrician attend all the deliveries with high risk factors and treat the asphyxiated newborn right after the delivery.
We have recorded the results of comparison of the death rate of immature babies at different birth weight treated in our hospital, and of the perinatal mortality in our Obstetric Department in the pie-improvement period of 5 years (1971-1975) and in the post-improvement period of 4 years (1976-1979) respectively.
The results are as follows:
1. A comparison of the death rate of immature babies at different birth weight.
In comparison of pre and post improvement, under 1, 000 g we haven't had enough cases to compare, besides most of the babies have died. However, at the weight between 1, 001-1, 500 g, the death rate has decreased from 39.4% down to 14.3%, at between 1, 501-2, 000g it has decreased from 11.4% down to 8.9%, and at between 2, 001-2, 500 g, from 6.9% to 1.1%.
2. A comparison of the perinatal mortality in our Obstetric Department.
The perinatal mortality has decreased from 18.5% down to 11.8% when we compare pre and post improvement. This result of the decrease depends on the decrease of fetal death at delivery and baby's death in the early neonatal period. Items of the causes of early neonatal death reveals that the deaths of immature babies and asphyxiated mature babies have decreased significantly.
From these results, we are fully realized the benefit of the regionalization of the neonatal medical treatment and I think we ought to promote such regionalization especially in rural area.

Twenty six adult patients who underwent prosthetic heart valve replacement and treated anti-thrombogenic therapy, were divided into 2 groups. One was administered Warfarin alone, another was administered Warfarin plus Aspirin (162mg/day) as antiplatelet therapy. Trapidil (300mg/day) was administered to all of the patients. Platelet aggregation, plasma level of TXB₂ (stable metabolite of thromboxane A₂), and 6-keto-PGF₁ (stable metabolite of PGI₂) were measured before and 1, 3, 6 months after Trapidil therapy. Platelet aggregability suppressed in both 2 groups. Plasma TXB₂ level, and TXB₂/6-keto-PGF₁ ratio showed a tendensy to decrease (p<0.05) 6 months after administration. In the Aspirin plus Trapidil group, platelet aggregability, serum TXB₂ level, and TXB₂/6-keto-PGF₁ ratio are significantly lower than that in the Trapidil only. These results suggest that Trapidil is clinically useful for antiplatelet agent, but the combined Aspirin plus Trapidil therapy is more efficacious than the Aspirin or Trapidil single therapy.

Background/Aims: Digital single-operator cholangioscopy (DSOC)-guided mapping biopsy (DMB) and tube-assisted mapping biopsy (TMB) are two techniques used for preoperative evaluation of biliary tract cancer (BTC). However, data regarding the diagnostic performance of these techniques are limited. Methods: We retrospectively examined consecutive patients with BTC who underwent either technique at our institution between 2018 and 2020. We evaluated the technical success rate, adequate tissue acquisition rate, and diagnostic performance of these techniques for the evaluation of lateral spread of BTC. Results: A total of 54 patients were included in the study. The technical success rate of reaching the target sites was 95% for DMB and 100% for TMB. The adequate tissue acquisition rate was 61% for DMB and 69% for TMB. The adequate tissue acquisition rate was low, especially for target sites beyond the secondary biliary radicles. The sensitivity of DMB alone was 39%, which improved to 65% when combined with visual impression. Experts demonstrated a higher negative predictive value and diagnostic accuracy with respect to both DSOC visual impression and DMB for the evaluation of lateral spread of BTC compared to trainees. Conclusions Adequate tissue acquisition rates were similar between the two techniques. Since DMB requires expertise, TMB may be an acceptable option when DSOC is unavailable or when DSOC expertise is limited.

Background/Aims: Selective bile duct or pancreatic duct cannulation remains a significant initial hurdle in endoscopic retrograde cholangiopancreatography (ERCP) despite advances in endoscopy and accessories. This study evaluated our experience with a rotatable sphincterotome in cases of difficult cannulation. Methods: We retrospectively reviewed ERCP cases using TRUEtome, a rotatable sphincterotome, as a rescue device for cannulation at a cancer institute in Japan from October 2014 to December 2021. Results: TRUEtome was used in 88 patients. Duodenoscopes were used for 51 patients, while single-balloon enteroscopes (SBE) were used for 37 patients. TRUEtome was used for biliary and pancreatic duct cannulation (84.1%), intrahepatic bile duct selection (12.5%), and strictures of the afferent limb (3.4%). Cannulation success rates were similar in the duodenoscope and SBE groups (86.3% vs. 75.7%, p=0.213). TRUEtome was more commonly used in cases with steep cannulation angles in the duodenoscope group and in cases requiring cannulation in different directions in the SBE group. There were no significant differences in adverse events between the two groups. Conclusions The cannulation sphincterotome was useful for difficult cannulations in both unaltered and surgically altered anatomies. It may be an option to consider before high-risk procedures such as precut and endoscopic ultrasound-guided rendezvous techniques.

Background/Aims: Hepaticojejunostomy anastomotic stricture (HJAS) is a feared adverse event associated with hepatopancreatobiliary surgery. Although balloon dilation for benign HJAS during endoscopic retrograde cholangiopancreatography with balloon-assisted enteroscopy has been reported to be useful, the treatment strategy remains controversial. Therefore, we evaluated the outcomes and risk factors of recurrent stenosis after balloon dilation alone for benign HJAS. Methods: We retrospectively analyzed consecutive patients who underwent balloon-assisted enteroscopy–endoscopic retrograde cholangiopancreatography for benign HJAS at our institution between July 2014 and December 2020. Results: Forty-six patients were included, 16 of whom had recurrent HJAS after balloon dilation. The patency rates at 1 and 2 years after balloon dilation were 76.8% and 64.2%, respectively. Presence of a residual balloon notch during balloon dilation was an independent predictor of recurrence (hazard ratio, 2.80; 95% confidence interval, 1.01–7.78; p=0.048), whereas HJAS within postoperative 1 year tended to be associated with recurrence (hazard ratio, 2.43; 95% confidence interval, 0.85–6.89; p=0.096). The patency rates in patients without a residual balloon notch were 82.1% and 73.1% after 1 and 2 years, respectively. Conclusions Balloon dilation alone may be a viable option for patients with benign HJAS without residual balloon notches on fluoroscopy.