Investigation of radiation safety management of nuclear medicine facilities in Japan; contamination of radioactivity in the draining-water system. A Working Group of Japanese Society of Nuclear Medicine for the Guidelines of Nuclear Medicine Therapy

Radiation safety management condition in Japanese nuclear medicine facilities were investigated by the questionnaire method. The first questionnaire was asked in all Japanese 1,401 Nuclear Medicine facilities. Answers from 624 institutes (44.5%) were received and analyzed. The radiation-safety management in nuclear medicine institutes was considered to be very well performed everyday. Opinion for the present legal control of nuclear medicine institutes was that the regulation in Japan was too strict for the clinical use of radionuclides. The current regulation is based on the assumption that 1% of all radioactivity used in nuclear medicine institutes contaminates into the draining-water system. The second questionnaire detailing the contamination of radioactivity in the draining-water system was sent to 128 institutes, and 64 answers were received. Of them, 42 institutes were considered to be enough to evaluate the contamination of radioactivity in the draining-water system. There was no difference between 624 institutes answered to the first questionnaire and 42 institutes, where the radioactivity in the draining-water system was measured, in the distribution of the institute size, draining-water system equipment and the radioactivity measuring method, and these 42 institutes seemed to be representative of Japanese nuclear medicine institutes. Contamination rate of radioactivity into the draining system was calculated by the value of radioactivity in the collecting tank divided by the amount of radionuclides used daily in each institute. The institutes were divided into two categories on the basis of nuclear medicine practice pattern; type A: in-vivo use only and type B: both in-vivo and in-vitro use. The contamination rate in 27 type A institutes did not exceed 0.01%, whereas in 15 type B institutes the contamination rate distributed widely from undetectable to above 1%. These results indicated that the present regulation for the draining-water system, which assumed that 1% of all radioactivity used in nuclear medicine institutes contaminated into draining-water system, should be reconsidered in nuclear medicine facilities where radionuclides are used only in in-vivo studies.     

Differential effects of lidocaine and mexiletine on relaxations to ATP-sensitive K+ channel openers in rat aortas

BACKGROUND: In cardiac myocytes, lidocaine reduces but mexiletine increases adenosine triphosphate (ATP)-sensitive K+ currents, suggesting that these class Ib antiarrhythmic drugs may differentially modify the activity of ATP-sensitive K+ channels. The effects of lidocaine and mexiletine on arterial relaxations induced by K+ channel openers have not been studied. Therefore, the current study was designed to evaluate whether lidocaine and mexiletine may produce changes in relaxations to the ATP-sensitive K+ channel openers cromakalim and pinacidil in isolated rat thoracic aortas. METHODS: Rings of rat thoracic aortas without endothelia were suspended for isometric force recording. Concentration-response curves were obtained in a cumulative fashion. During submaximal contractions to phenylephrine (3 x 10(-7) M), relaxations to cromakalim (10(-7) to 3 x 10(-5) M), pinacidil (10(-7) to 3 x 10(-5) M), or diltiazem (10(-7) to 3 x 10(-4) M) were obtained. Lidocaine (10(-5) to 3 x 10(-4) M), mexiletine (10(-5) to 10(-4) M) or glibenclamide (5 x 10(-6) M) was applied 15 min before addition of phenylephrine. RESULTS: During contractions to phenylephrine, cromakalim and pinacidil induced concentration-dependent relaxations. A selective ATP-sensitive K+ channel antagonist, glibenclamide (5 x 10(-6) M), abolished these relaxations, whereas it did not alter relaxations to a voltage-dependent Ca2+ channel inhibitor, diltiazem (10(-7) to 3 x 10(-4) M). Lidocaine (more than 10(-5) M) significantly reduced relaxations to cromakalim or pinacidil in a concentration-dependent fashion, whereas lidocaine (3 x 10(-4) M) did not affect relaxations to diltiazem. In contrast, mexiletine (more than 10(-5) M) significantly augmented relaxations to cromakalim or pinacidil. Glibenclamide (5 x 10(-6) M) abolished relaxations to cromakalim or pinacidil in arteries treated with mexiletine (10(-4) M). CONCLUSIONS: These results suggest that lidocaine impairs but mexiletine augments vasodilation mediated by ATP-sensitive K+ channels in smooth muscle cells.     

Highly sensitive analysis for N-myc amplification in neuroblastoma based on fluorescence in situ hybridization

BACKGROUND/PURPOSE: The N-myc amplification status in neuroblastoma has been evaluated previously for the whole tumor by the Southern blot method. The aim of this study is to evaluate the effectiveness of the fluorescence in situ hybridization (FISH) method to analyze N-myc amplification in neuroblastoma and compare the findings with those using the Southern blot method. METHODS: In 26 neuroblastoma primary tumors and metastatic lesions, the N-myc amplification status was evaluated by both the Southern blot method and FISH method. RESULTS: Of the 22 samples with no N-myc amplification using Southern blot, no cells with N-myc amplification using FISH were present in 21 of the samples. However, one metastatic liver lesion showed 16% of the nuclei to display more than 10 copies of N-myc based on FISH analysis. In the 4 remaining samples with N-myc amplification using the Southern blot method (17 copies, 15 copies, 6 copies, and 3 copies), the rates of cells with more than 10 copies of N-myc based on a FISH analysis were 79%, 68%, 94%, and 9%, respectively. CONCLUSIONS: The FISH method can detect more accurately N-myc amplification than the Southern blot method either when the rate of cells with N-myc amplification is low or intratumor heterogeneity is present.     

Anterior surgery with short fusion using the Zielke procedure for thoracic scoliosis: focus on the correction of compensatory curves

Anterior instrumentation is recommended to correct idiopathic thoracolumbar or lumbar scoliosis through short fusion within the major curve. Only a few reports exist of anterior surgical correction for thoracic scoliosis. This study assessed the results of Zielke instrumentation for thoracic curve and analyzed the three-dimensional correction of deformity, especially correction of the uninstrumented compensatory curve. Seventeen patients, who had undergone selective thoracic correction and fusion using the Zielke procedure to treat thoracic scoliosis, had been followed for at least 3 years. Three-dimensional correction was evaluated radiographically. Furthermore, three-dimensional back deformities were evaluated using a topographic body scanner. Twelve patients with a single thoracic curve and five with a double curve were all female, with a mean age of 14.6 years. The preoperative main thoracic curve was 54.8 degrees +/- 10.5 degrees (range, 40-78 degrees), and it was 23.8 degrees +/- 10.5 degrees (range, 7-40 degrees) at the final follow-up examination (p < 0.0001). The average correction rate of the main curves was 56.6%. By correcting the thoracic curve, the upper and lower compensatory curves were corrected spontaneously without surgical instrumentation, with average correction rates of 45.1% and 50.2%, respectively. The average correction loss of the main curve was 2.3 degrees. The hump angle measured using a topographic body scanner decreased from 12.8 degrees +/- 4.5 degrees to 8.4 degrees +/- 4.3 degrees after surgery (p = 0.0001). Of the three patients in whom the rod broke up, only one showed a correction loss of 10 degrees; however, bony fusion was obtained. Anterior short fusion for thoracic scoliosis appears to offer significant correction, stabilization, and spontaneous correction of the compensatory lumbar curve without limiting lumbar motion.     

Utility of endoscopic ultrasonography in assessing the indications for endoscopic surgery of submucosal esophageal tumors

BACKGROUND: The submucosal tumor (SMT) of the esophagus presents good indications for minimal invasive surgery, such as endoscopic or thoracoscopic resection. However, it is essential that the layer of origin be ascertained. The SMT can be detected as hypoechoic lesions in the wall of the esophagus, and the intramural location can be estimated in terms of destruction or deviation of the ultrasonic layer structure of the esophagus. METHODS: To test the efficacy of this approach, a series of patients were examined by an endoscopic ultrasonography (EUS). RESULTS: In one patient, the lesion was diagnosed as located in the muscularis mucosa, and endoscopic resection was performed. In another four patients, the lesions appeared to be in the proper muscle layer, and enucleation was carried out under thoracoscopy or open surgery. Histologically, all of the lesions were leiomyomas, and the EUS diagnosis was correct in all of the patients. CONCLUSIONS: Thus, the intramural condition of SMTs can be estimated and indications for endoscopic or thoracoscopic resection assessed by this approach.     

Major organ function under mechanical support: comparative studies of pulsatile and nonpulsatile circulation

We examined a major organ function during 3 h biventricular assisted circulation after acute myocardial infarction model in the pig. In left ventricular circulation, the outflow cannula was placed in the ascending aorta and an inflow cannula through the mitral valve in the left ventricle. A pump (pulsatile group, Zeon Medical, Inc., Tokyo, Japan and nonpulsatile group, Nikkiso HPM-15, Nikkiso, Inc., Tokyo, Japan) was connected to each cannula. In right ventricular circulation, the outflow cannula was placed in the pulmonary artery and an inflow cannula in the right ventricle. The right ventricular circulation was supported by a nonpulsatile pump (Nikkiso HPM-15). The items measured were the regional blood flows of the cortex and medulla in the kidney, white matter and gray mater in brain, and liver; renal arterial flow; carotid arterial flow; portal vein flow; common hepatic arterial flow; arterial ketone body ratio (AKBR); and lactate/pyrubic acid (L/P). In the pulsatile group, the renal cortical blood flow increased, and the medulla blood flow decreased. On the other hand, in the nonpulsatile group, both regional blood flows decreased. That means that in the pulsatile assisted group intrarenal redistribution improved rather than in the nonpulsatile assisted group. In addition the liver regional blood flow, AKBR, and L/P showed significant differences between the pulsatile and nonpulsatile groups. On the other hand, the white matter and gray matter regional blood flows and carotid arterial flow did not show significant differences between the groups. The results of our study indicated that pulsatile circulation produced superior circulation in the kidney and liver, and microcirculation on the cell level was superior as well in early treatment of acute heart failure.     

Total Esophagectomy versus Proximal Esophagectomy for Esophageal Cancer at the Cervicothoracic Junction

To investigate the adequate extent of esophagectomy and lymphadenectomy for an esophageal cancer localized at the cervicothoracic junction, the mortality and morbidity rates, survival rates, and patterns of recurrence were retrospectively analyzed in two groups—14 patients who underwent total esophagectomy with or without laryngectomy and 15 patients who underwent proximal esophagectomy with or without laryngectomy—at Kurume University Hospital from 1981 to 1996. Proximal esophagectomy with or without laryngectomy resulted in a lower hospital mortality rate and better overall survival for patients who underwent curative esophagectomy compared with total esophagectomy with or without laryngectomy. Multivariate analysis indicated that the extent of esophagectomy (total esophagectomy versus proximal esophagectomy) was not a prognostic factor. The incidence of recurrence was not different between the two groups. Lymph node metastasis or recurrence from such esophageal cancers was localized to the neck and upper mediastinum. For an esophageal cancer localized at the cervicothoracic junction, therefore, proximal esophagectomy with or without laryngectomy and with cervical and upper mediastinal lymphadenectomy could be better indicated for preselected patients.     

An ultraviolet absorbing pigment causes a narrow-band violet receptor and a single-peaked green receptor in the eye of the butterfly Papilio

The distal photoreceptors in the tiered retina of Papilio exhibit different spectral sensitivities. There are at least two types of short-wavelength sensitive receptors: an ultraviolet receptor with a normal spectral shape and a violet receptor with a very narrow spectral bandwidth. Furthermore, a blue receptor, a double-peaked green receptor and a single-peaked green receptor exist. The violet receptor and single-peaked green receptor are only found in ommatidia that fluoresce under ultraviolet illumination. About 28% of the ommatidia in the ventral half of the retina exhibit the UV-induced fluorescence. The fluorescence originates from an ultraviolet-absorbing pigment, located in the most distal 70 microns of the ommatidium, that acts as an absorption filter, both for a UV visual pigment, causing the narrow spectral sensitivity of the violet receptor, and for a green visual pigment, causing a single-peaked green receptor.     

Effect of metalloproteinase inhibitor on corneal cytokine expression after alkali injury.

PURPOSE: Interleukin (IL)-1alpha and IL-6 levels in the cornea are greatly elevated during the early stages after an alkali burn in mice. The authors investigated the effect of synthetic inhibitor of matrix metalloproteinase (SIMP) on the expression of inflammatory cytokines in alkali-burned murine corneas and evaluated the clinical appearance of the eyes. METHODS: After 0.5N NaOH-alkali burns to 400 corneas of ICR mice, 200 received 400 microg/ml of SIMP topically 4 times a day while 200 corneas were similarly treated with vehicle only. At days 4, 7 and 14 after injury, each cornea was assigned a clinical score for corneal opacity, corneal epithelial defect, hyphema and cataract. Extracts of injured corneas in each group were then assayed for cytokine production using ELISA systems for IL-1alpha, IL-1beta, IL-6 and tumor necrosis factor-alpha (TNF-alpha). RESULTS: The levels of IL-1alpha, IL-1beta and IL-6 were significantly lower in the SIMP-treated group than in the vehicle-treated group 7 days after the burn. However, levels of these cytokines were similar in the SIMP and non-SIMP groups at days 4 and 14. Levels of TNF-alpha did not differ between both groups at any postinjury time. In the SIMP-treated corneas, there was less opacification and hyphema formation and epithelial regeneration was faster. CONCLUSIONS: Topical application of SIMP in alkali-burned murine corneas reduced the expression of IL-1alpha, IL-1beta, and IL-6 and lessened the severity of the injury.