Measurement of scatter radiation on MDCT equipment using an OSL dosimeter

The recent introduction of multi-detector row computed tomography (MDCT) has made it possible to scan the entire abdomen within approximately 10 sec in procedures such as interventional radiology computed tomography (IVRCT), which are associated with operator exposure. Therefore, anxious patients and patients who are not able to remain still can be examined with an assistant. In the present study, radiation exposure to the assistant was estimated, and the distribution of scattered radiation near the gantry was measured using an optically stimulated luminescence (OSL) dosimeter. Simultaneous measurements were obtained using a direction storage (DIS) dosimeter for reference. The maximum value of 1.47 mSv per examination was obtained at the point closest to the gantry's center (50 cm from the center at a height of 150 cm above the floor) . In addition, scattered radiation decreased as the measurement point was moved further from the gantry's center, falling below the limit of detection (0.1 mSv or less) at 200 cm and at the sides of the gantry. OSL dosimeters are also employed as personal dosimeters, permitting reliable values to be obtained easily. They were found to be an effective tool for the measurement of scattered radiation, as in the present study, helping to provide better understanding of the distribution of scattered radiation within the CT room.     

Upregulation of corticotropin-releasing hormone gene expression in the paraventricular nucleus of cyclophosphamide-induced cystitis in male rats

We examined the effects of cyclophosphamide (CP)-induced cystitis on the expression of corticotropin-releasing hormone (CRH) mRNA in the paraventricular nucleus (PVN) and the serum levels of adrenocorticotropic hormone (ACTH) using in situ hybridization histochemistry and radioimmunoassay. In addition, the expression of AVP heteronuclear (hn) RNA and neuronal nitric oxide synthase (nNOS) mRNA was also examined in the PVN of a CP-induced cystitis model. We found that the levels of CRH mRNA were significantly increased in the PVN at 2 h after intraperitoneal administration of CP compared to those in saline-treated rats. The CRH mRNA levels in the PVN peaked at 12 h after CP administration and the levels were still significantly higher than those in saline-treated group at 24 h after CP administration. The serum ACTH levels in CP-treated group were also significantly higher compared to those in saline-treated group at any of the time points examined. Unlike previous findings showing upregulation of nNOS mRNA and AVP hnRNA under somatic nociceptive states, the levels of nNOS mRNA and AVP hnRNA were unchanged in the PVN following CP-induced cystitis, visceral nociceptive stimulation. These results suggest that visceral nociceptive stimulation as well as somatic nociceptive stimulation may activate the hypothalamo-pituitary axis but the hypothalamic neuroendocrine responses produced by visceral nociceptive stimulation may be different from those produced by somatic nociceptive stimulation.     

Apparent bradycardia-dependent advanced second-degree atrioventricular block

A 65-year-old man with repeated chest discomfort and dizzy spells was transferred by an emergency car. On the way to hospital, his pulse was palpable as regular 4 to 5 beats followed by an unpalpable period of about 4 s. His electrocardiographic monitor showed that 4 to 5 sinus QRS complexes were followed by consecutive 3 to 4 blocked sinus P waves, which occurred repeatedly. When PP intervals gradually shortened during inspiration, sinus impulses were conducted to the ventricles, whereas when PP intervals lengthened during expiration, 3 to 4 sinus impulses were blocked in succession. An attempt was made to explain the mechanism for such apparent bradycardia-dependent atrioventricular block by using the concepts of periodic increases in vagal tone due to respiration and concealed electrotonic conduction of blocked impulses. Such a peculiar form of advanced second-degree atrioventricular block has never been reported before.     

Suppressed complement activation in human decay accelerating factor transgenic porcine liver cross-circulated with nonhuman primates

BACKGROUND: We developed an extracorporeal liver perfusion (ECLP) system as a liver-assist device. In this study, we evaluated the safety of the ECLP using human decay accelerating factor (hDAF) transgenic porcine livers in healthy baboons. METHODS: Livers were isolated from five hDAF transgenic pigs and five nontransgenic pigs for the ECLP. Ten cross-circulations between the ECLP and healthy baboons were performed without immunosuppressive agents. Cross-circulation was discontinued in any of the following circumstances: elevated hepatic arterial (>200 mm Hg) or portal (>60 mm Hg) perfusion pressure, massive exudate from the graft liver, mild macroscopic hemolysis, thrombocytopenia, or 24-hr well-conditioned cross-circulation. RESULTS: The cross-circulations with nontransgenic porcine livers were discontinued at 4.4+/-1.2 hr (mean+/-standard deviation) because of high perfusion pressure (n=2) or hemolysis (n=3). Three cross-circulations with hDAF transgenic porcine livers were performed for 24 hr; the other two cross-circulations were discontinued at 13 and 17 hr because of massive exudate and thrombocytopenia, respectively. The duration was 20.4+/-5.1 hr. Deposition of membrane attack complex in the hDAF transgenic porcine liver was less than that in the nontransgenic liver, although immunoglobulin-M deposition was comparable. The porcine livers showed no apparent interlobular bleeding or lobular necrosis. All porcine livers maintained bile production during the cross-circulation. No baboons showed any serious complications after the cross-circulation. CONCLUSION: The hDAF transgenic porcine liver reduced complement activation in xenoperfusion with healthy nonhuman primate blood and led to extended duration of cross-circulation.     

Membrane pore size impacts performance of a xenogeneic bioartificial liver

BACKGROUND: We have developed a novel bioartificial liver (BAL) composed of porcine hepatocyte spheroids in a reservoir design. A semipermeable membrane is used to protect the spheroids from immune-mediated damage. This study was designed to assess the influence of membrane pore size on performance of the spheroid reservoir BAL. METHODS: Eight healthy dogs were studied during primary and secondary exposures to the spheroid reservoir BAL using membranes with small (10 nm) or large (200 nm) pores. BAL performance was assessed by multiple functional assays. Spheroids were examined microscopically before and after all BAL treatments. Titers of xenoreactive antibody were monitored until elective death of animals on day 42. RESULTS: Viability and functional performance of spheroids were significantly greater after all BAL treatments that used membranes with 10-nm versus 200-nm pores. Reduced performance in the 200 nm group was associated with 7.7-fold and 78.0-fold rise in xenoreactive antibody titers after first and second treatments, respectively. Dogs in the 10 nm group remained hemodynamically stable during all BAL treatments, whereas those in the 200 nm group experienced acute hypotension (P<0.001) during second BAL exposures. Microscopic examination of spheroids after BAL treatments indicated that deposition of canine proteins, including complement, was associated with reductions in both viability and functional performance of the BAL. CONCLUSIONS: The elicited immune response of healthy dogs to a xenogeneic BAL was blocked and BAL performance significantly improved by reducing the permeability of the BAL membrane.     

Usefulness of arbitrarily primed polymerase chain reaction (AP-PCR) method for DNA fingerprinting analysis of Mycobacterium tuberculosis (MTB); comparison between DNA restriction fragment-length polymorphism (RFLP) method and AP-PCR method

We have been analyzing cases suspected as outbreak of Mycobacterium tuberculosis in Tokyo using RFLP method. This time we analyzed 27 strains of MTB from 5 cases in two hospitals, a family, member of social activity and stuff of a corporation using both RFLP and AP-PCR methods. At 4 cases, over 80% of strains were same pattern in each cases with RFLP and AP-PCR and were identified as a patient to patients transmission of MTB. At one case, in a hospital, each strains were completely different patterns at both methods, which showed it was not a outbreak case. Results of RFLP and AP-PCR were completely same, which indicates AP-PCR is also useful and rapid method for epidemiological analysis of MTB infection as well as RFLP.     

Comparative study of the effects of pyruvate and CG-120 in preventing experimental oxalate urolithiasis in rats

Male Wistar-strain rats which had been fed a calcium-oxalate lithogenic diet (a glycolate diet) developed urinary calculi in 4 weeks. Sodium pyruvate or CG-120 (a mixture of citrate salts) had been added to this diet to determine its effect in preventing lithogenicity. Rats in the group fed a pyruvate diet had, however, almost no stones in the urinary system. Rats in the CG-120 group showed results somewhat similar to those in the pyruvate group. Increased urinary citrate excretion was observed in both groups and could be implicated as the main inhibitory factor in stone formation. Therefore, it can be concluded that CG-120 exerts a beneficial effect close to that of pyruvate in preventing calculi formation and that both substances cause a high citrate excretion in urine.