[Derivation of Conversion Formula of Image Quality Figure (IQFinv) Values by Old and New Analysis Software for Mammographic Contrast-detail Phantom]

PURPOSE

This study deals with the conversion of the image quality figure (IQF_inv) values with CDMAM Analyser ver. 1 (old analysis software) used to analyse the images of CDMAM 3.4 phantom into the IQF_inv values with a new analysis software, that is, CDMAM Analyser (ver. 2 and ver. 2.3), which is a software improved to be closer to human visual evaluation.

METHODS

The IQF_inv values were calculated using four mammography units and three analysis software. The IQF_inv values using the old and new software were compared.

RESULTS

The IQF_inv values had no difference according to mammography units and beam quality. The conversion formula of IQF_inv from CDMAM Analyser ver. 1 to CDMAM Analyser ver. 2 was derived. Furthermore, the conversion formula of IQF_inv from CDMAM Analyser ver. 1 to CDMAM Analysis ver. 2.3 was also derived.

CONCLUSION

Using each conversion formula, the IQF_inv values using the old software can be converted to those using the new software. There was a slight difference between the IQF_inv values using the new software.

[Comparison between Variance and Edge Methods for Measuring Image Resolution Properties in Digital Mammography]

We studied the image resolution properties in digital mammography using the variance and edge response function methods. The associated measurements were made using a polymethylmethacrylate phantom of 0-40 mm thickness while maintaining the incident dose to the detector constant, as well as with and without using the phantom but by varying the level of exposure to the detector. The results obtained using the two methods were compared on the object plane of the mammography unit with compensation for the magnification and rejection of the scattered radiation. In this unit, the imaging process of resolution enhancement may be performed according to the phantom thickness, shape of test device, exposure level, and so on. The modulation transfer function values of the variance method were slightly higher than those of the edge method, approximately 6% at 2 cycles/mm and 8% at 4 cycles/mm without resolution enhancement processing. We concluded that the variance method is more suitable than the edge method for the constancy test or quality control because of its lower coefficient of variation.

RECENT TRITIUM CONCENTRATION OF MONTHLY PRECIPITATION IN JAPAN

To obtain a better understanding of recent tritium concentration and its seasonal cycle in Japan, monthly precipitation samples were collected in Hokkaido, Gifu and Okinawa prefectures from June 2014 to December 2017. The arithmetic mean ( ± standard deviation) of tritium concentrations in precipitation samples from Hokkaido, Gifu and Okinawa were estimated to be 0.62 ± 0.27 Bq L-1, 0.32 ± 0.12 Bq L-1 and 0.13 ± 0.05 Bq L-1, respectively. These results indicate that the concentrations increase with latitude. In addition, the highest and the lowest concentrations appeared in spring and summer, respectively. To clarify the origins and sources of these cycles, further analyses of chemical compositions of precipitation and meteorological conditions are needed.

Pressure generated at the instant of impact between a liquid droplet and solid surface

The prime objective of this study is to answer the question: How large is the pressure developed at the instant of a spherical liquid droplet impact on a solid surface? Engel first proposed that the maximum pressure rise generated by a spherical liquid droplet impact on a solid surface is different from the one-dimensional water-hammer pressure by a spherical shape factor (Engel 1955 J. Res. Natl Bur. Stand. 55(5), 281-298). Many researchers have since proposed various factors to accurately predict the maximum pressure rise. We numerically found that the maximum pressure rise can be predicted by the combination of water-hammer theory and the shock relation; then, we analytically extended Engel's elastic impact model, by realizing that the progression speed of the contact between the gas-liquid interface and the solid surface is much faster than the compression wavefront propagation speed at the instant of the impact. We successfully correct Engel's theory so that it can accurately provide the maximum pressure rise at the instant of impact between a spherical liquid droplet and solid surface, that is, no shape factor appears in the theory.

INTERNATIONAL STANDARDS ON FOOD AND ENVIRONMENTAL RADIOACTIVITY MEASUREMENT FOR RADIOLOGICAL PROTECTION: STATUS AND PERSPECTIVES

Radiological protection is a matter of concern for members of the public and thus national authorities are more likely to trust the quality of radioactivity data provided by accredited laboratories using common standards. Normative approach based on international standards aims to ensure the accuracy or validity of the test result through calibrations and measurements traceable to the International System of Units. This approach guarantees that radioactivity test results on the same types of samples are comparable over time and space as well as between different testing laboratories. Today, testing laboratories involved in radioactivity measurement have a set of more than 150 international standards to help them perform their work. Most of them are published by the International Standardization Organization (ISO) and the International Electrotechnical Commission (IEC). This paper reviews the most essential ISO standards that give guidance to testing laboratories at different stages from sampling planning to the transmission of the test report to their customers, summarizes recent activities and achievements and present the perspectives on new standards under development by the ISO Working Groups dealing with radioactivity measurement in connection with radiological protection.

[Comparison of Contrast to Noise Ratio and Signal Difference to Noise Ratio Based on QA and QC Guidelines in CR Mammography]

The measurement methods of contrast to noise ratio (CNR) and signal difference to noise ratio (SDNR) in digital mammography are different among several quality assurance (QA) guidelines, that is, the type of pixel value (PV), phantom shape, location of aluminum plate, and the size of region of interest (ROI) principally differ in data acquisition. We compared CNR (SDNR) obtained from three QA guidelines. They are the European Reference Organisation for Quality Assured Breast Screening and Diagnostic Services (EUREF), the International Electrotechnical Commission (IEC), and the International Atomic Energy Agency (IAEA). In EUREF and IEC, CNR was calculated using linearized pixel value (LPV). In IAEA, because the type of pixel value to use in SDNR was not specified, SDNR was calculated using PV and LPV, and CNR was calculated using LPV. Target/filter combinations are molybdenum/molybdenum (Mo/Mo) and molybdenum/rhodium (Mo/Rh). Applied various tube voltages are 25, 30, and 35 kV, and various phantom thicknesses are 20, 45, and 70 mm of polymethyl methacrylate (PMMA). The PV-SDNR of IAEA showed the largest value among the three methods, following LPV-CNR of IEC, LPV-CNR of EUREF at 20 mm PMMA thickness. In IAEA, SDNR changed by the kind of pixel value (PV or LPV). When CNR is calculated, every researcher should describe the type of guidelines, the kind of pixel value, and formula for calculation.

[Influence of Detector Radiation Damage on CR Mammography Quality Control]

Recently, radiation damage to the detector apparatus employed in computed radiography (CR) mammography has become problematic. The CR system and the imaging plate (IP) applied to quality control (QC) program were also used in clinical mammography in our hospital, and the IP to which radiation damage has occurred was used for approximately 5 years (approximately 13,000 exposures). We considered using previously acquired QC image data, which is stored in a server, to investigate the influence of radiation damage to an IP. The mammography unit employed in this study was a phase contrast mammography (PCM) Mermaid (KONICA MINOLTA) system. The QC image was made newly, and it was output in the film, and thereafter the optical density of the step-phantom image was measured. An input (digital value)-output (optical density) conversion curve was plotted using the obtained data. The digital values were then converted to optical density values using a reference optical density vs. digital value curve. When a high radiation dose was applied directly, radiation damage occurred at a position on the IP where no object was present. Daily QC for mammography is conducted using an American College of Radiology (ACR) accreditation phantom and acrylic disc, and an environmental background density measurement is performed as one of the management indexes. In this study, the radiation damage sustained by the acrylic disc was shown to differ from that of the background. Thus, it was revealed that QC results are influenced by radiation damage.

Generation of single bubbles of various sizes using a slitting elastic tube

The generation of single bubbles is often required in laboratory research. However, it is very difficult to control bubble production, especially for a required bubble size, by using the same orifice. In this study, we demonstrate the control of bubble formation by combining a pulsed acoustic pressure wave in a gas phase and a slitting elastic tube. By elastically deforming the tube using the acoustic wave, we can control the bubble radius in the range from 300 μm to 5 mm by using the same tube without liquid flow. This method can produce bubbles with good repeatability and small individual differences in the tubes.

[Measurement of residual effect in the amorphous selenium flat panel detector system]

The purpose of this study was to evaluate the residual effect generated by the amorphous selenium flat panel detector system (a-Se FPD). A residual effect occurs as a result of the addition of delayed electrons by previous X-ray irradiation joining the signal and change in detector sensitivity caused by hole-electron recombination or trapped electrons in a-Se. To evaluate the effect of previous radiation exposure, we irradiated a-Se FPD that were half-shielded by a 3 mm thick lead plate. A residual effect was generated in irradiated areas, with the unirradiated areas serving as reference points. Next, we removed the lead plate and took a new image using uniform irradiation. The difference in pixel value between irradiated and nonirradiated areas was measured using a variety of time intervals between each exposure. Through a comparison of pixel values from images taken over various time intervals, we discovered our system needs 20 hours to return to a normal state and become capable of producing a residual-free image.

[Estimation of entrance skin dose from fluoroscopy for tracking fiducial markers during real-time tumor-tracking radiotherapy-simulation with a sine wave respiration model-]

The real-time tumor-tracking radiotherapy system includes two sets of fluoroscopes that detect the fiducial markers in or near the tumor constantly during radiotherapy. The treatment beam is irradiated to the tumor only when fiducial markers are located in the target position. Treatment time is extended in case of large respiratory tumor motion. A high-power fluoroscopic X-ray is required in the case of fiducial markers in parenchymal organs with heavy X-ray attenuation. It was a concern that radiodermatitis was caused by an increasing entrance skin dose from the fluoroscopic X-ray. In order to estimate the entrance skin dose from the fluoroscopic X-ray, we measured the entrance skin dose rate through the use of a method recommended by the Japanese Society of Radiological Technology. We applied sine wave simulation to resemble the respiratory motion of the tumor. In conclusion, we confirm that entrance skin dose from fluoroscopy during RTRT is lower than the threshold dose for radiodermatitis.

[Development of comprehensive image processing technique for differential diagnosis of liver disease by using multi-modality images-pixel-based cross-correlation method using a profile-]

Imaging techniques such as high magnetic field imaging and multidetector-row CT have been markedly improved recently. The final image-reading systems easily produce more than a thousand diagnostic images per patient. Therefore, we developed a comprehensive cross-correlation processing technique using multi-modality images, in order to decrease the considerable time and effort involved in the interpretation of a radiogram (multi-formatted display and/or stack display method, etc). In this scheme, the criteria of an attending radiologist for the differential diagnosis of liver cyst, hemangioma of liver, hepatocellular carcinoma, and metastatic liver cancer on magnetic resonance images with various sequences and CT images with and without contrast enhancement employ a cross-correlation coefficient. Using a one-dimensional cross-correlation method, comprehensive image processing could be also adapted for various artifacts (some depending on modality imaging, and some on patients), which may be encountered at the clinical scene. This comprehensive image-processing technique could assist radiologists in the differential diagnosis of liver diseases.

[Selection of parameters for multi-objective frequency processing in CR mammography: visual evaluation of mammographic phantom images]

The multi-objective frequency processing installed in the FCR5000R (Fuji Film Medical) is superior to the conventional processing used in the FCR9000 (Fuji Film Medical) in evaluating frequency processing. A suitable combination of parameters for multi-frequency-processing in computed radiography (CR) mammography was evaluated. The paired-comparison method using phantom images was performed for the visual evaluation. Results showed that the evaluation score of mass and fiber lesions depended on the multi-frequency balance type (MRB) parameter, and the low-frequency-cycle emphasizing parameter had the highest score. In contrast, the score of microcalcifications depended on the degree of multi-frequency enhancement (MRE). The most suitable parameters for the multi-frequency processing of every size and type of breast lesion were not obtained. However, MRB=A, MRT=p, and MRE=1.0 can be recommend for CR mammography.

[Measurement of effective dose of the assisting person in diagnostic X-ray examination]

We measured the effective dose received by the person assisting the patient at diagnostic X-ray examination. Measurement was done when a patient's chest, abdomen, lumbar vertebrae, hip joint, skull, cervical vertebrae, or knee joint was examined by radiography. A body phantom including human bones exposed to radiation was used in the role of the patient. Some exposure conditions for these measurements were the same as those used routinely in computed radiography. Effective dose was measured directly with an ionization survey meter. As a result, the effective dose of the person assisting with axial projection of the hip joint was 124 microSv, which was higher than that for other regions and projections. If the assisting person helped a patient without using any protective device, the effective dose would be low enough to ignore. However, because medical staff are frequently exposed to radiation, optimal protection is crucial to prevent unnecessary radiation.

Characteristics of radon and its progeny concentrations in air-conditioned office buildings in Tokyo

A series of measurements were carried out to understand the characteristics of radon and its progeny in air-conditioned office buildings. Long-term measurements of radon were made with etched track detectors. Continuous measurements of radon and its progeny concentrations were also conducted in some buildings to study their temporal variations. The results show that radon and its progeny concentrations routinely varied along with the working activities. They are generally low while people are working, due to air conditioning, whereas they rise steadily after the air conditioning stops. When considering action levels not only in homes but also workplaces, attention should be paid to annual doses from the viewpoint of radiation protection. The annual dose is generally estimated with a long-term measurement of radon concentration using a passive device such as an etched track detector. Since its reading corresponds to a long-term average concentration regardless of working hours, but, the annual dose will be overestimated. When comparing a real dose after considering the working hours, they differ by a factor of more than 2.

[Significance of the visual evaluation method using the two-visit method (two-sample preference test suggested by Ferris)]

To increase the accuracy of the visual evaluation method, we studied the significance of the two-sample preference test using the two-visit method, as proposed by Ferris. Advantages of this method include not only its ability to estimate whether the image quality of the sample is statistically the same but also its ability to distinguish the difference between samples more clearly than when using the conventional two-sample preference test or paired-comparison method. However, a disadvantage is that this method involves two observations of the same sample. When using chest images, even if a difference between the samples is not recognizable by the conventional method, a significant difference can be elicited with this method. The data obtained by this method can be evaluated with the paired-comparison method, so some samples may be ranked as well. Therefore, we verified that the two-sample preference test, which Ferris formulated, is useful in visual evaluations.

Hand-assisted laparoscopic hepatic resection

Thanks to recent advances, performance of liver resection is now possible using laparoscopic procedures. However, still there are some difficulties to overcome. The hand-assisted method lends safety and reliability to the laparoscopic procedure. A 54-year-old man diagnosed with hepatocellular carcinoma (HCC) was referred for hepatectomy. Angiography with computed tomography (CT) scans revealed a 2-cm hepatocellular carcinoma (HCC) at segment V, close to the gallbladder. A hand-assisted laparoscopic hepatic resection was performed. Four 10-mm trocars, one for wall lifting and three for working, were placed in the upper abdomen. A small incision was added at the right side of umbilicus, and the operator's left hand was inserted through it. A microwave tissue coagulator and laparoscopic ultrasonic dissector were used for liver resection. Total operation time was 162 min; blood loss was 20 g. The postoperative course was uneventful, and the postoperative hospital stay was 7 days. We thus demonstrated that laparoscopic liver resection is safer and easier when the hand of the operator can be inserted into the abdomen. The small incision does not greatly diminish the benefits that accrue from minimally invasive laparoscopic surgery. The hand-assisted procedure allows better access to the tumor. In addition, hand assistance restores the sense of touch to the operator and is an effective means of controlling sudden and unexpected bleeding.

Contribution from thoron on the response of passive radon detectors

In order to evaluate the reliability of measured values of radon concentration, a thoron sensitivity test for passive radon detectors was carried out. To do this test, a thoron chamber system was first set up. The system consists of four parts: an exposure chamber, a gas generator, an environmental monitor, and a measuring device. Five types of radon detectors were examined using the chamber system. After connecting the exposure chamber with the gas generator through an external pump, thoron gas was circulated through the system. The detectors were exposed to thoron-rich air for several days. The mean ratio between thoron and radon concentrations throughout the exposure period was 10:1. Some of the detectors provided values different from the actual radon concentration. Although the presence of thoron can be negligible in most cases, it is necessary to check the thoron contribution to the detector response with the proposed or similar test before practical use.

[Reconstruction of chest wall using myocutaneous flap]

Reconstruction of chest wall using myocutaneous flap has been performed in 2 cases. A 72-year-old female referred to our hospital for locally recurrent left breast cancer without any distant metastases. The other patient was a 77-year-old female, having locally recurrent liposarcoma of the left lateral chest wall. Chest wall was resected with wide margin of normal tissue, and myocutaneous flaps of latissimus dorsi were used for reconstruction of skin defect (13 x 8 cm and 14 x 10 cm) in both cases. Although additional split-thickness skin graft was required for one of them, myocutaneous flaps were useful for the reconstruction of widely defected chest wall. By using this technique, wider margin can be obtained, which could decrease the risk for local recurrence of malignant tumor.

Dependence of indoor radon concentration on the year of house construction

The dependence of indoor radon concentration on the year of house construction was studied using the results of two nationwide indoor radon surveys in Japan. The data of radon concentration in the surveys were classified into structure type as well as year of construction to obtain the current radon concentration for each structure type as a function of year of construction. The indoor radon concentration in wooden houses was found to be relatively constant with year of house construction until 1960, and then decreased, whereas the radon concentration in concrete houses increased sharply in houses constructed after 1970. The concentration in concrete houses built before 1975 was almost the same as that in contemporary wooden houses. However, the concentration in concrete houses built at present was about two times higher than that in wooden houses. The time trends found for wooden and concrete houses in the first nationwide indoor radon survey were confirmed by the second nationwide survey. In addition, these same time trends were mostly observed in the data classified into 7 districts in Japan. The increase of indoor radon concentration in concrete houses provides relatively high dose, and this increasing trend seems to continue, judging from the results of two nationwide surveys.

[Recovery from out-of-hospital cardiac arrest after mild hypothermia: report of two cases]

We report two patients with out-of-hospital cardiac arrest who recovered after hypothermia therapy. A 25-year-old man and a 16-year-old boy were transferred to our hospital after cardiopulmonary arrest due to idiopathic ventricular fibrillation and hypertrophic cardiomyopathy, respectively. We carried out hypothermia therapy using cooling blankets, and the patients were maintained at 32-33 degrees C for 96 and 36 h, respectively. After slow rewarming, they regained consciousness and recovered. During hypothermia, hypokalemia and arrhythmia occurred. Their arrest times (no spontaneous circulation and no CPR) were 10 min and 8 min, and CPR times (no spontaneous circulation while CPR was being performed) were 24 min and 20 min, respectively. In cases where the duration of ischemia is prolonged, the prognosis is expected to be poor. Therefore, we believe that hypothermia therapy is beneficial for such patients.

[Anesthetic management of abdominal gunshot wound--a report of three cases]

This is a case report of anesthetic management of abdominal gunshot wound. Two patients had upper abdominal wound involving the liver and the inferior vena cava. They died of uncontrolled bleeding. Third patient had lower abdominal injury involving the ascending colon and small intestine. The patient survived the injury and showed good recovery. In a case of the abdominal gunshot injury, prompt diagnosis and laparotomy are mandatory. Multiple intravenous routes are necessary in the upper part of the body for massive infusion and transfusion. Unusual hemostasis methods such as atrio-caval shunt or abdominal clamping of the aorta must be considered in case of injury in the inferior vena cava.

Protective effects of candesartan cilexetil (TCV-116) against stroke, kidney dysfunction and cardiac hypertrophy in stroke-prone spontaneously hypertensive rats

The effects of chronic treatment with an angiotensin II receptor antagonist, candesartan cilexetil (TCV-116, 0.1, 1, 10 mg/kg), and an angiotensin converting enzyme inhibitor, enalapril maleate (enalapril, 10 mg/kg), on the development of end-organ damage were examined in stroke-prone spontaneously hypertensive rats (SHRSP). The control SHRSP developed severe hypertension with stroke signs and increased urinary protein excretion. TCV-116 (0.1 mg/kg) reduced the stroke incidence and urinary protein excretion without affecting the blood pressure. TCV-116 (1 and 10 mg/kg) and enalapril reduced blood pressure, the stroke incidence, the urinary indices and left ventricular weight. Circulating renin-angiotensin system (RAS) and renal renin mRNA expression were significantly accelerated or tended to be accelerated in the control SHRSP with end-organ damages. A low dose of TCV-116 tended to reduce the RAS indices in plasma by improving the damages, whereas a high dose (10 mg/kg) increased them by the reflexes with blocking RAS. The present results indicate that chronic All blockade reduces the increase in blood pressure, end-organ damages and RAS related to the damages in SHRSP.

Regional hemodynamic effects of candesartan cilexetil (TCV-116), an angiotensin II AT1-receptor antagonist, in conscious spontaneously hypertensive rats

The regional hemodynamic effects of candesartan cilexetil (TCV-116), a selective angiotensin II AT1-receptor antagonist, and enalapril, an angiotensin-converting enzyme inhibitor, were compared in conscious spontaneously hypertensive rats (SHR). A 7-day repeated administration study was carried out. TCV-116 (1 mg/kg, p.o.) and enalapril (10 mg/kg, p.o.) reduced blood pressure to the same extent 5 hr after administration on the 1st and the 7th day. At these points, the cardiac index and organ or tissue blood flow were measured by the non-radioactive colored dye-extraction microsphere technique. Repeated administration of TCV-116, and single and repeated administration of enalapril significantly increased renal blood flow without any changes in the cardiac index. TCV-116 and enalapril also tended to increase splanchnic blood flow following the 1st dose but not the 7th dose. No significant changes in blood flow were observed in the brain, heart, adrenal, skin and skeletal muscle. These results suggest that the antihypertensive effects of TCV-116 and enalapril are attributable to the systemic reduction of vascular resistance caused by the dilatation of blood vessels. These hemodynamic effects of TCV-116, like those of enalapril, may be beneficial in the treatment of hypertension.

Candesartan (CV-11974) dissociates slowly from the angiotensin AT1 receptor

The mechanisms of the insurmountable antagonism of 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]1H-benzimid azole -7-carboxylic acid, candesartan (CV-11974), an angiotensin AT1 receptor antagonist, on angiotensin II-induced rabbit aortic contraction were examined in contraction and binding studies. Preincubation of the rabbit aorta with CV-11974 (0.1 nM) for 30 min reduced the maximal contractile response to angiostensin II by approximately 50%. This insurmountable antagonism of CV-11974 was reversed in the presence of losartan (1 microM), a surmountable angiotensin AT1 receptor antagonist. The inhibitory effect of CV-11974 on angiotensin II-induced contraction persisted longer after washing than did that of losartan but was irreversible. Scatchard analysis of [3H]CV-11974 binding in bovine adrenal cortical membranes indicated the existence of a single class of binding sites (Kd = 7.4 nM). Competition binding studies using angiotensin II receptor agonists and antagonists have demonstrated that [3H[CV-11974 binding sites may be identical to angiotensin AT1 receptors. The dissociation rate of [3H]CV-11974 binding (t1/2 = 66 min) was 5 times slower than that of [125I]angiotensin II binding (t1/2 = 12 min). These results suggest that the insurmountable antagonism by CV-11974 is due to its slow dissociation from angiotensin AT1 receptors.

Combined effects of the angiotensin II antagonist candesartan cilexetil (TCV-116) and other classes of antihypertensive drugs in spontaneously hypertensive rats

The antihypertensive effects of an angiotensin II antagonist, candesartan cilexetil (TCV-116), and other classes of antihypertensive drugs (including a calcium antagonist, manidipine; a diuretic, hydrochlorothiazide (HCTZ); an alpha-blocker, prazosin; and a beta-blocker, atenolol) administered in combination were examined in spontaneously hypertensive rats by oral administration daily for 2 wk. TCV-116 at 1 mg/kg lowered the blood pressure by about 50 and 30 mmHg, 5 and 24 h after dosing, respectively. The blood pressure was slightly lowered by HCTZ at 10 mg/kg, but it was synergistically reduced when HCTZ was given in combination with TCV-116. Manidipine at 3 mg/kg lowered the blood pressure by about 50 mmHg 1 h after administration. When manidipine was given in combination with TCV-116, blood pressure was reduced additively. Prazosin at 1 mg/kg lowered the blood pressure by 40 to 50 mmHg 1 h after dosing. When prazosin was given in combination with TCV-116, the reduction was intensified more than additively, to about 100 mmHg. Atenolol at 50 mg/kg lowered the blood pressure by 10 to 20 mmHg 5 h after dosing. Even when atenolol was administered in combination with TCV-116, the reduction in blood pressure was virtually the same as that observed when TCV-116 was given alone. TCV-116 and HCTZ had no effect on the pulse rate, whereas manidipine and prazosin both increased it, owing to reflex tachycardia, and atenolol decreased it. TCV-116 had no effect on the change in the pulse rate induced by these antihypertensive drugs and no effect on HCTZ-induced diuresis. TCV-116 and HCTZ each caused a significant increase in plasma renin concentration (PRC), and prazosin caused a slight elevation. Manidipine had no effect on the PRC, whereas atenolol reduced it. Given in combination with TCV-116, these antihypertensive drugs had the same effect on the elevated PRC induced by TCV-116 as they did on the basal PRC when administered alone. These results suggest that antihypertensive drugs that cause compensatory activation of the renin-angiotensin system have more marked antihypertensive activity when given in combination with TCV-116, but that there will is no combined effect on the pulse rate.

Anorectal stenosis in a neonate: report of a case and review of the Japanese literature

We report herein the case of an infant with anorectal stenosis successfully treated by staged surgery. At 1 day of age, the anal orifice showed circumferential stenosis located 5 mm from the anal verge and extending into the anal canal for approximately 1 cm; however, no hypertrophic raphe or bucket handle appearance were observed, and no associated anomalies such as a presacral mass or sacral dysgenesis were found. At 2 days of age, the infant underwent a sigmoid colostomy under the diagnosis of low anorectal stenosis, followed by a successful anorectoplasty, performed through a sacroperineal approach when he was 8 months old. An analysis of 13 other cases of anorectal stenosis from the Japanese literature indicates that this type of malformation should be treated by staged surgery, as an initial colostomy in the neonatal period, followed by anorectoplasty through a sacroperineal approach during infancy.

Comparison of the antihypertensive effects of the new angiotensin II (AT1) receptor antagonist candesartan cilexetil (TCV-116) and the angiotensin converting enzyme inhibitor enalapril in rats

Antihypertensive effects of an angiotensin (Ang) II receptor antagonist, candesartan cilexetil (TCV-116), were compared with those of an angiotensin converting enzyme (ACE) inhibitor, enalapril, in spontaneously hypertensive rats (SHR), 2-kidney, 1-clip hypertensive rats (2K, 1C-HR) and 1-kidney, 1-clip hypertensive rats (1K, 1C-HR). CV-11974, the active form of TCV-116, had no inhibitory activity for plasma ACE. In rats, TCV-116 inhibited the pressor responses to Ang I, Ang II, and Ang III without an effect on the bradykinin (BK)-induced depressor response. Enalapril inhibited only the Ang I-response and potentiated the BK-response. In SHR, the antihypertensive effect of TCV-116 (10 mg/kg) was larger than the maximum antihypertensive effect of enalapril and was not intensified by combination with enalapril. Administration of CV-11974 potentiated the maximum antihypertensive effect of enalapril. Although both agents reduced blood pressure in 2K, 1C-HR, only TCV-116 had a marked antihypertensive effect in 1K, 1C-HR. These findings indicate that TCV-116 is more effective than enalapril in reducing blood pressure in SHR and 1K, 1C-HR, and that the BK- and/or prostaglandin-potentiating effect of enalapril contributes little to its antihypertensive mechanism in SHR.

TCV-116 inhibits renal interstitial and glomerular injury in glomerulosclerotic rats

TCV-116 and enalapril were given in two stages: (early phase) for 6 to 10 weeks to 5/6 nephrectomized (NX) rats two weeks after nephrectomy, 12-week-old Wistar fatty (WF) rats and 7-week-old spontaneously hypercholesterolemic (SHC) rats; and (late phase) for 6 to 16 weeks to 5/6 NX rats 11 weeks after nephrectomy, 27-week-old WF rats and 10-week-old SHC rats. Urinary albumin, blood pressure (BP), glomerular filtration rate (GFR) and renal histology were examined. In the early phase, both agents inhibited proteinuria and tended to inhibit glomerulosclerosis. TCV-116 also inhibited interstitial inflammation. The antiproteinuric effects did not necessarily correlate with the BP-lowering effects. In the late phase, both agents showed equal antiproteinuric and antihypertensive effects. In 5/6NX and WF rats, TCV-116 inhibited tubulointerstitial inflammation/fibrosis, glomerulosclerosis and renal dysfunction, but enalapril had little effect on these parameters. In the SHC rats, TCV-116 inhibited renal tubulointerstitial inflammation and glomerulosclerosis, but enalapril inhibited only glomerulosclerosis. After drug administration, there was a positive correlation between proteinuria and BP, and a negative correlation between the severity of tissue damage and GFR, but not BP. These findings suggest that initial BP-independent tubulointerstitial inflammation may enhance glomerulosclerosis in the late phase, and TCV-116 might prevent the development of glomerulosclerosis through inhibition of angiotensin II-mediated tubulointerstitial damage in these models.

Spiral computed tomography for biliary dilatation

Spiral computed tomography (SCT), which consists of rapid volumetric data acquisition and planar image display, was performed on 12 patients with biliary dilatation after excisional procedure. The technique was evaluated for image quality and impact on clinical practice. All patients safely underwent SCT scanning after intravenous cholangiography (IVC) without any sedations. In 11 of 12 patients reliable biliary images were obtained and three-dimensional (3D) reconstruction images of the biliary system with bilioenteric anastomosis were generally of diagnostic quality even in young children. As a consequence, IVC-SCT technique appears to have the potential for improving the efficacy and safety of diagnostic CT in investigation of the biliary system. In particular, this technique may be useful for detecting bilioenteric anastomotic conditions in follow-up studies of pediatric patients with biliary dilatation.

A fundamental study of a computed X-ray densitometry system for bone mineral measurement in the second metacarpal bone

The effect of radiographic exposure factors such as the photographic film density, X-ray tube voltage, and focus-film distance on the indices of bone mineral obtained by computed X-ray densitometry (CXD), a newly developed X-ray microdensitometric system, was investigated. sigma GS/D, which corresponded to the bone mineral density divided the integrated bone mineral by the bone width of the second metacarpal bone, was influenced by these exposure factors, whereas MCI, which represented the ratio of the cortical bone to whole bone, was independent of them. Present results indicated that the focus-film distance between 85 and 115 cm, the X-ray tube voltage in 45-60 kV, and a photographic density of lower than 1.82-1.86 of the screen-film combination should be used to assess quantitatively bone mineral of the second metacarpal bone using the CXD system.

Antihypertensive effects of a highly potent and long-acting angiotensin II subtype-1 receptor antagonist, (+-)-1-(cyclohexyloxycarbonyloxy)ethyl 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]-1H- benzimidazole-7-carboxylate (TCV-116), in various hypertensive rats

The antihypertensive effects of (+-)-(cyclohexyloxycarbonyloxy)ethyl2-ethoxy-1-[[2'-(1H- tetrazol-5- yl)biphenyl-4-yl]methyl]-1-H-benzimidazole-7-carboxylate (TCV-116), an angiotensin II (AII) subtype-1 receptor antagonist, were studied in various hypertensive and normotensive rats, using 2-n-butyl-4-chloro-5-hydroxymethyl-1-[(2'-(1H-tetrazol-5-yl)bip hen yl-4- yl)methyl]-imidazole, potassium salt (losartan) as a reference compound. TCV-116 is a prodrug, which is converted in vivo to the active component, 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl)]methyl]-1H- benzimidazole-7-carboxylic acid (CV-11974). In spontaneously hypertensive rats (SHR) p.o. TCV-116 (0.1 mg/kg) demonstrated a sustained antihypertensive effect that lasted for more than 10 hr and the dose that reduced the blood pressure by an average of 25 mm Hg for 24 hr (ED25), was 0.68 mg/kg. Intravenous CV-11974 reduced the blood pressure with an ED25 of 0.0027 mg/kg. Repeated p.o. administration of TCV-116 (1 mg/kg) to SHR once daily for 2 weeks reduced the blood pressure by 30 to 50 mm Hg over 24 hr without any heart rate changes. The antihypertensive effects of TCV-116 correlated well with the inhibition of angiotensin II-induced contractile responses of aortic strips prepared ex vivo after p.o. administration of TCV-116. Oral TCV-116 had a sustained antihypertensive effect with ED25 of 0.03 and 0.23 mg/kg in two-kidney, one-clip and one-kidney, one-clip hypertensive rats, respectively, and was much more potent in SHR and renal-hypertensive rats than losartan.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of an angiotensin II receptor antagonist, CV-11974, and its prodrug, TCV-116, on production of aldosterone

In dispersed rabbit adrenocortical glomerulosa cells, a non-peptide angiotensin II (AT1) receptor antagonist, CV-11974 (10(-10)-10(-5) M), competitively inhibited angiotensin II- or angiotensin III-stimulated aldosterone production, whereas PD123177, an angiotensin AT2 receptor antagonist, did not. CV-11974 inhibited aldosterone production induced by 4 mM K+ but not by 12 mM K+. CV-11974 had no effect on adrenocorticotropic hormone-stimulated aldosterone or corticosterone production, but inhibited angiotensin II-stimulated corticosterone production. In the rat, TCV-116, the prodrug of CV-11974, (0.1 and 1 mg/kg, p.o.) markedly reduced the elevation of both plasma aldosterone concentration and blood pressure induced by i.v. infusion of angiotensin II. In spontaneously hypertensive rats, TCV-116 at daily p.o. doses of 0.1, 1 and 10 mg/kg for 2 weeks caused a dose-dependent reduction of blood pressure and plasma aldosterone concentration without affecting plasma corticosterone. Thus, TCV-116 inhibited the induction of aldosterone production by not only exogenous but also endogenous angiotensin II.

Inhibition of rabbit aortic angiotensin II (AII) receptor by CV-11974, a new nonpeptide AII antagonist

The angiotensin II (AII) antagonistic action of CV-11974 (2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl] benzimidazole-7-carboxylic acid) was investigated in an AII-receptor binding assay using rabbit aortic membranes and an AII-induced contraction assay using rabbit aortic strips. A single class of [125I]AII-(Sar1,Ile8) binding sites was found in the membranes with a dissociation constant (Kd) of 0.15 nM and a receptor concentration (Bmax) of 86.9 fmol/mg protein. CV-11974 markedly reduced Kd without affecting Bmax. The specific binding of [125I]AII-(Sar1,Ile8) in this preparation was inhibited completely by CV-11974 [the inhibition constant (Ki) = 0.64 nM], DuP 753 [an angiotensin II type I (AT1) receptor-selective antagonist] (Ki = 51 nM) and EXP3174 (an active metabolite of DuP 753) (Ki = 6.8 nM), but was not affected by PD123177 (an AT2 receptor-selective antagonist). These results suggest that the single binding site in rabbit aortic membranes is an AT1 receptor subtype. The affinity of CV-11974 to these AT1 receptors was approximately 80 and 10 times higher than that of DuP 753 and EXP3174, respectively. CV-11974 showed no appreciable affinity for the AT2 receptors found in bovine cerebellum. In the in vitro functional study, CV-11974 markedly reduced the AII-induced maximal contractile response of rabbit aortic strips (pD'2 = 9.97). In contrast, Compound 7-H, which lacks the carboxyl group at the benzimidazole ring of CV-11974, inhibited the contraction in a competitive manner. The inhibition by CV-11974 was long lasting. These results suggest that CV-11974 is a potent and long-acting AT1 receptor-selective, competitive antagonist. The carboxyl group at the benzimidazole ring plays an important role in the interaction between CV-11974 and the AT1 receptor.

Pharmacological profile of a highly potent and long-acting angiotensin II receptor antagonist, 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4- yl]methyl]-1H-benzimidazole-7-carboxylic acid (CV-11974), and its prodrug, (+/-)-1-(cyclohexyloxycarbonyloxy)-ethyl 2-ethoxy-1-[[2'-(1H-tetrazol-5- yl)biphenyl-4-yl]methyl]-1H-benzimidazole-7-carboxylate (TCV-116)

The angiotensin II (AII) antagonistic action of 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl-1H-benzi mid azole-7 - carboxylic acid (CV-11974) was examined in in vitro assay systems, including AII receptor binding assay using membrane fractions of bovine adrenal cortex or rabbit aorta and AII-induced contraction assay using rabbit aortic strips, and CV-11974 and its prodrug, (+/-)1-(cyclohexyloxycarbonyloxy)ethyl 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]-1H- benzimidazole-7-carboxylate (TCV-116), were examined in an in vivo system of AII-induced pressor response in conscious rats. DuP 753 or EXP3174 (the main active metabolite of DuP 753) was used as the reference compound. CV-11974 inhibited the binding of [125I] AII to the bovine adrenal cortical membrane and rabbit aortic membrane with IC50 values of 1.12 x 10(-7) and 2.86 x 10(-8) M, respectively. Similar results were obtained with EXP3174. CV-11974 interacted with AII in these membrane fractions with subtype 1 receptor in a competitive manner. CV-11974 at 10(-5) M did not affect the binding of [125I]AII to subtype 2 (AT2) receptor in bovine cerebellum. CV-11974 selectively inhibited the AII-induced contraction of rabbit aortic strips in a noncompetitive manner (pD' 2, 9.97); it had no effects on the contraction induced by norepinephrine, KCl, serotonin, prostaglandin F2 alpha or endothelin. EXP3174 showed a pD'2 value of 8.95 for the AII-induced contraction. CV-11974 given intravenously and TCV-116 given orally inhibited the AII-induced pressor response in rats with ID50 values of 0.033 mg/kg and 0.069 mg/kg, respectively. These effects of CV-11974 and TCV-116 were 12 and 48 times more potent than those of EXP3174 and DuP 753, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of U74006F on neurologic function and brain edema after fluid percussion injury in rats

The effect of the 21-aminosteroid U74006F, an inhibitor of iron-dependent lipid peroxidation, on neurologic outcome and cerebral edema was evaluated in adult male Sprague-Dawley rats subjected to a fluid percussion temporal brain injury followed by 45 min of hypoxia (PaO2 = 30.0 mm Hg). The rats were divided randomly into five groups. Bolus injections of a control drug or U74006F (1.0, 3.0, 10.0, or 30.0 mg/kg) were given 3 min and 3 h after the injury. Twenty-four hours after the injury, the neurologic status was evaluated, the rats were killed, and brain water content was determined by microgravimetry. U74006F did not significantly reduce brain water content at any dose level, nor did it affect rotorod walking or activity scores. However, rats treated with U74006F at a dose of 10.0 mg/kg had significantly better motor function scores (p < 0.05) than rats in the control group. These findings demonstrate the usefulness of U74006F as a cerebroprotective agent in this model of experimental head injury.

[A case of repetitive monomorphic ventricular tachycardia]

We present a case treated with aprindine and metoprolol combined with a DDD type pacemaker for repetitive monomorphic ventricular tachycardia. A 50-year-old man was admitted because of palpitation and near syncope attack. Electrocardiogram showed repetitive monomorphic ventricular tachycardias (RBBB LAD type) and R-R interval of about 440 msec and I degree A-V block in sinus rhythm. Electrophysiologic study disclosed that overdrive pacing in HRA suppressed ventricular tachycardias. Left ventriculography revealed a dilated left ventricular and decreased contractility. Antiarrhythmic agents such as quinidine sulfate, procainamide, disopyramide, mexiletine, lidocaine and propranolol were not effective. But, the combination of propranolol and aprindine decreased the rate of the ventricular tachycardia. With aprindine 60 mg/day and metoprolol 60 mg/day combined with the atrioventricular sequential pacing at 85/min, ventricular tachycardia completely disappeared.