Detector for dual-energy digital radiography

A detection scheme is described that allows one to accomplish dual-energy scanned projection digital radiography without switching the x-ray tube voltage. The method employs a high/low atomic number detector sandwich that simultaneously separates the x-ray beam transmitted by the patient into low and high energy components. To test the method, the response of a scanning linear array of energy-sensitive detectors was simulated, and bone and soft tissue images of an anthropomorphic chest phantom were obtained at 140 kVp. These were compared with similar images obtained by switching the x-ray tube voltage from 80 kVp to a heavily filtered 140 kVp. For comparable entrance skin exposures, the dual-energy detector images required a lower tube load and resulted in higher noise levels. The latter is attributable to the fact that the separation in energy between the high and low energy components is smaller with the dual-energy detector than with the voltage switching technique, and to misregistration problems associated with the simulation methodology. A detector design is also discussed that would result in improved energy separation and lower noise levels. In view of this possibility and the tube loading advantage, the method looks promising for digital scanned projection radiography.     

Parenteral administration of glipizide sodium salt, an inhibitor of adenosine triphosphate-sensitive potassium channels, prolongs short-term survival after severe controlled hemorrhage in rats

OBJECTIVE: Recent experimental evidence suggests that activation of adenosine triphosphate (ATP)-sensitive potassium channels contributes to vascular failure and early mortality after hemorrhagic shock. The present investigation evaluated the effects of the water-soluble sodium salt of glipizide, an inhibitor of ATP-sensitive potassium channels, in anesthetized and awake rats subjected to severe controlled hemorrhage. DESIGN: Prospective, randomized, controlled study. SETTING: Animal research laboratory. SUBJECTS: Male Wistar rats. INTERVENTIONS: Anesthetized rats were subjected to bleeding to reduce mean arterial pressure to either 40 or 35 mm Hg, which was maintained constant for 60 mins. In addition, awake rats underwent blood withdrawal of 4.25 mL/100 g over 20 mins. At the end of the hemorrhage period and 30 mins later, the animals received intravenous (5 and 20 mg/kg) or intramuscular (10 and 40 mg/kg) injections of glipizide sodium salt or vehicle. MEASUREMENTS AND MAIN RESULTS: In anesthetized rats subjected to pressure-controlled hemorrhage, glipizide sodium salt improved mean arterial pressure in a dose-dependent manner. Compared with the vehicle-treated animals, mean arterial pressure increased from 41.6 +/- 4.6 to 63.1 +/- 3.1 mm Hg in the 20 mg/kg intravenous group and from 33.2 +/- 4.9 to 54.0 +/- 4.7 mm Hg in the 40 mg/kg intramuscular group 60 mins after a 40-mm Hg shock. Furthermore, the drug did not affect the hemorrhage-induced changes in blood glucose concentrations. However, the higher doses of glipizide sodium salt attenuated the increments in plasma concentrations of lactate, alanine aminotransferase, creatinine, and amylase. Moreover, the higher doses markedly improved short-term survival after pressure- and volume-controlled bleeding. Overall, the intramuscular injections of the drug exerted salutary effects that were comparable to the intravenous administration. CONCLUSIONS: In rats, parenteral administration of the water-soluble glipizide sodium salt attenuates vascular and end-organ dysfunction associated with severe hemorrhagic shock and prolongs short-term survival. The intramuscular administration provides comparable benefits as obtained by the intravenous injection.     

Thyrotoxic periodic paralysis in a Chinese population

We retrospectively evaluated the characteristics of adult patients admitted with thyrotoxic hypokalaemic periodic paralysis in Hong Kong. From 1984 to 1993, 45 Chinese adult patients were admitted with acute limb weakness, plasma potassium ⩽3.5 mmol/l and thyrotoxicosis confirmed by laboratory investigations. All but one were male. Seventy-five percent of attacks occurred between 9pm and 9am. Half of the attacks occurred between July and October (49.1%), most commonly in August (20%). Mean (+SEM) plasma potassium on admission was 2.17 ± 0.08 mmol/l (range 1.1-3.5). In 15 episodes (27.3%), plasma potassium on recovery exceeded 5.0 mmol/l, while in three episodes (5.5%), potassium exceeded 6.0 mmol/l. No patient had a positive family history of thyrotoxic periodic paralysis. Only 28.9% had a known history of thyrotoxicosis before their first presentation with periodic paralysis. Twenty-seven (60%) had clinical evidence of thyrotoxicosis. Although all were biochemically thyrotoxic, 11.4% had only a mild degree of thyrotoxicosis (suppressed thyroid-stimulating hormone, high free thyroxine, but normal free triiodothyronine). One quarter of the patients had a normal erythrocyte zinc concentration, indicating either a short history of thyrotoxicosis or transient thyrotoxicosis. The diagnosis of thyrotoxic hypokalaemic paralysis should always be considered in Chinese patients with acute muscle weakness, especially in young males. Absence of clinical thyrotoxicosis does not exclude the diagnosis. Plasma potassium should be monitored carefully during treatment to prevent rebound hyperkalaemia.      

Live births after management of severe OHSS by GnRH antagonist administration in the luteal phase

Ovarian hyperstimulation syndrome (OHSS) is a serious complication of ovarian stimulation protocols. Currently, no curative therapy exists and the main preventive option is cycle cancellation. Gonadotrophin-releasing hormone (GnRH) antagonist administration in the luteal phase was recently proposed as a new approach for the management of patients with established severe OHSS. Three polycystic ovarian syndrome patients undergoing IVF treatment developed severe OHSS, diagnosed 6 days after oocyte retrieval. On day 6, the patients underwent blastocyst transfer and received GnRH antagonist for 4 days, combined with luteal phase support using exogenous oestradiol and progesterone. Two patients had successful pregnancies that resulted in births of healthy infants, while one patient had a biochemical pregnancy. In all patients, established severe OHSS regressed to a moderate form of the syndrome, no pregnancy-induced life-threatening OHSS was observed, while a short monitoring period was required at an outpatient level, avoiding the need for patient hospitalization. This is the first report in the literature on GnRH antagonist administration in the luteal phase, combined with embryo transfer and exogenous oestradiol and progesterone supplementation. This novel treatment was effective in the regression of established severe OHSS, and resulted in the birth of healthy infants.     

Quantitative real-time RT-PCR and chromogenic in situ hybridization: precise methods to detect HER-2 status in breast carcinoma

Background  

HER-2 gene testing has become an integral part of breast cancer patient diagnosis. The most commonly used assay in the clinical setting for evaluating HER-2 status is immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). These procedures permit correlation between HER-2 expression and morphological features. However, FISH signals are labile and fade over time, making post-revision of the tumor difficult. CISH (chromogenic in situ hybridization) is an alternative procedure, with certain advantages, although still limited as a diagnostic tool in breast carcinomas.     

用毫微球增加体外小鼠腹腔巨噬细胞与大鼠肝细胞对庆大霉素的摄取

用³H-庆大霉素制备了聚氰基丙烯酸正丁酯毫微球。结果表明,毫微球可使小鼠腹腔巨噬细胞的cpm达³H-庆大霉素溶液对照组的6.34倍,使大鼠肝细胞的cpm在1,12和24h分别达到³H-庆大霉素溶液对照组的27.74,9.03和8.36倍。毫微球的粒径、使用的稳定剂种类、表面活性剂包裹以及庆大霉素的投药量等对摄取量均有明显影响。本研究为筛选细胞内给药系统提供了依据。     

MANAGEMENT OF INVASIVE ASPERGILLOSIS WITH ITRACONAZOLE

SUMMARY A case of chronic invasive paranasal aspergillosis is described which, despite an initial poor prognosis, responded well to treatment with itraconazole.