Microwave Thermotherapy of Prostatic Enlargement—Analysis of Radiometric Thermometry Using a Hybrid Bio-heat Equation

The radiometric temperature measurement included in a commercial device for transurethral microwave thermotherapy (TUMT) of the prostate was investigated utilizing both phantom experiments and computer simulations. Two finite element (FE) models were developed. One is in part based on the experimental results, and serves as a complement to the experiments, while the other describes a perfused tissue situation for which the hybrid bio-heat equation was used to model the thermal effects of blood perfusion. The aim of the study was to investigate how the radiometric thermometer is affected by the temperature close to the antenna, and to analyze the relation between blood perfusion, temperature distribution and radiometric temperature measurement.

It was found that the radiometric temperature was affected to a greater extent by the temperature very close to the antenna, in contrast to what has been expected in previous studies. The blood perfusion was found to mainly affect the temperature distribution outside the maximum temperature (located 2–3?mm outside the cooled catheter). Thus, the relation between the radiometric temperature and the temperature in the treated area is relatively weak.     

Microwave thermotherapy of prostatic enlargement--analysis of radiometric thermometry using a hybrid bio-heat equation

The radiometric temperature measurement included in a commercial device for transurethral microwave thermotherapy (TUMT) of the prostate was investigated utilizing both phantom experiments and computer simulations. Two finite element (FE) models were developed. One is in part based on the experimental results, and serves as a complement to the experiments, while the other describes a perfused tissue situation for which the hybrid bio-heat equation was used to model the thermal effects of blood perfusion. The aim of the study was to investigate how the radiometric thermometer is affected by the temperature close to the antenna, and to analyze the relation between blood perfusion, temperature distribution and radiometric temperature measurement. It was found that the radiometric temperature was affected to a greater extent by the temperature very close to the antenna, in contrast to what has been expected in previous studies. The blood perfusion was found to mainly affect the temperature distribution outside the maximum temperature (located 2-3 mm outside the cooled catheter). Thus, the relation between the radiometric temperature and the temperature in the treated area is relatively weak.     

Selection of chemotherapy for patient treatment utilizing a radiometric versus a cloning system

From the 1950s to the 1970s, a number of in vitro systems that measured inhibition of glucose metabolism were used to predict the responsiveness of patients' tumors to chemotherapy. In vitro-in vivo correlations were excellent, with true positive predictions ranging from 68% to 96% and true negative predictions of 95% to 100%. The radiometric system is a new in vitro technique that measures the conversion of 14C-glucose to 14CO2. The system already has been utilized to screen prospective new antineoplastic agents for cytotoxicity. The present study was undertaken to determine if the radiometric system might be used to predict correctly the responsiveness of an individual patient's tumor to single-agent or combination-agent chemotherapy. Fifty-six tumor specimens were divided and tested for drug sensitivity in the radiometric system and a conventional human tumor clonning system. Overall, there was a significant correlation between in vitro and in vivo results for the conventional cloning system (P = 0.03). However, there was no significant relationship between in vitro and in vivo results for the radiometric system. The radiometric system consistently failed to predict the tumor's clinical sensitivity to single agents. A radiometric system is not useful in predicting the responsiveness of a patient's tumor to single agent chemotherapy and is not a replacement for the more biologically attractive human tumor cloning system.     

Evaluation of Radiometric System for Detecting Bacteremia

An automated radiometric system (BACTEC, Johnston Laboratories) for detection of bacteremia was evaluated in parallel with a standard blood culture system in use in our laboratory. Of 1,445 blood cultures from 484 patients with possible bacteremia, 106 sets of cultures (excluding 39 presumed contaminated), representing 56 patients, were positive by both methods. The conventional system yielded 85 positive cultures from 48 patients, whereas the BACTEC system yielded 84 positive cultures from 43 patients. The BACTEC system failed to detect 22 cultures that were positive in the conventional system, and the conventional system failed to detect 21 cultures that were positive in the BACTEC system. The detection efficiency was generally equivalent in the two systems except for the lower detection rates of anaerobes and Enterobacter aerogenes by the BACTEC system and the lower detection rates of Torulopsis glabrata and, possibly, Pseudomonas sp. (group IVD) in the conventional system. The BACTEC system had a slight advantage over the conventional system in the time interval to detection of positivity. Approximately 20% of the positive cultures detected by the BACTEC system were detected on the first day of incubation compared with 7% by the conventional system. The recovery rates and detection times of anaerobes were less efficient by the BACTEC system than by the conventional system. It does not appear that the radiometric method has much advantage over available conventional methods.     

Effect of lithium chloride on the thyroid gland of white rats]

The morphological and functional changes in the thyroid tissue of white rats injected lithium chloride at doses 0.5 mekv/kg and 1.0 mekv/kg (groups 1 and 2, respectively) during three weeks were studied by the radiometric, histological and biochemical methods. The radiometric, histological and biochemical methods. The inhibitory action of lithium chloride on hormonogenesis in the thyroid gland and secretion of thyroid hormones into the blood was proved to be directly related to the lithium dose and concentration in the blood. The data of intravital radiometric and morphological analysis of the organs of the 1st group animals suggest some activization of the gland function, with the secretion of the hormones into the blood being suppressed. Increased concentration of the drug inhibits hormonogenesis and secretion of thyroid hormones into the blood.     

Automated Radiometric Detection of Bacteria in 2,967 Blood Cultures

A new radiometric method for the automatic detection of bacterial growth in blood cultures has been compared with conventional methods. A total of 2,967 cultures from 1,280 patients suspected of having bacteremia were studied. A 2-ml amount of blood was inoculated into culture media in which the glucose was labeled with carbon-14. The release of (14)CO(2) by bacterial metabolism was checked hourly for 18 to 24 hr, daily for the next 2 days, and, on the 12th day, with an automated instrument. A 10-ml amount of blood was studied by conventional bacteriological techniques. In 125 cultures from 50 patients, there was bacterial growth in at least one of the routine media. Of these, the radiometric method detected 102 cultures from 40 patients. In 111 cultures from 48 patients, there was radiometric detection of bacterial growth. In all of these cultures, there was detection of bacterial growth in subcultures from the radioactive medium. Of these, the routine laboratory detected 98 cultures from 40 patients. Neither method detected all patients with bacteremia. Among the 57 patients positive by one or both methods, routine techniques detected bacteria in 87% and the radiometric method detected bacteria in 85%. Seventy per cent of the cultures were detected first by the radiometric method, 65% on the day of inoculation. Our results suggest that the radiometric method is faster than conventional techniques and comparable in accuracy. Its great advantage is that it is simple, automatic, and can be extended to automatic detection of bacterial sensitivity to antibiotics.     

Evaluation of (14C)aminopyrine clearance for determination of gastric mucosal blood flow.

This study has demonstrated high correlation between the radiometric and spectrophotometric determinations of gastric mucosal aminopyrine clearance. The radiometric method is technically easier, allows a larger number of samples to be determined and is safer to the subject. The clearance of small amounts of [14C]aminopyrine was unaffected by large doses of unlabeled aminopyrine showing that mucosal extraction is not concentration limited. Small amounts of [14C]aminopyrine may provide an excellent tool for examining the role of mucosal blood flow in the pathogenesis of gastric disease in man.     

Multicenter evaluation of the fully automated Bactec MGIT 960 system for susceptibility testing of Mycobacterium tuberculosis to pyrazinamide: comparison with the radiometric Bactec 460TB system

One hundred and fifty clinical isolates of Mycobacterium tuberculosis were tested for susceptibility to pyrazinamide using the fully automated Bactec MGIT 960 system and the radiometric Bactec 460TB system. The overall concordance rate between MGIT 960 and radiometric system was 100% and the mean turnaround times to report the susceptibility test results were almost identical (6.37 and 6.8 days, respectively).     

Differences in regional brain catecholamine metabolism after a decrease in blood pressure

Using a sensitive radiometric assay for determination of catecholamines, the α-methyl-para-tyrosine-induced catecholamine disappearance was studied in discrete brain regions of rats after acute hypotension. The decrease in blood pressure was induced either by controlled haemorrhage or by the administration of guanethidine. In both cases an increase of the α-methyl-para-tyrosine-induced noradrenaline disappearance was observed in the nucleus commissuralis and the A₁-region in the medulla oblongata. In the paraventricular nucleus the disappearance of noradrenaline as well as that of adrenaline was enhanced. The results are in support for the involvement of catecholamines in particular brain regions in the regulation of blood pressure.     

Radiometric Method for Detection of Bacteremia

A study was performed with simulated blood cultures to evaluate the production of (14)CO(2) as an index of bacterial growth. With a range of inoculum sizes from 4 to 4,250 colony-forming units, it was not possible to detect (14)CO(2) within 6 hr after inoculation in 59 separate experiments. In a limited trial with patients' blood cultures, the radiometric method failed to provide any earlier evidence of bacteremia than did routine broth cultures.     

Radiometric Measurement of Metabolic Activity of Mycobacterium lepraemurium

A sensitive and nondestructive radiometric method has been applied to the detection of metabolism of Mycobacterium lepraemurium, as a model for the study of the metabolism and substrate requirements of M. leprae. The method is based on the measurement of the (14)CO(2) produced through the bacterial conversion of [U-(14)C]acetate or [U-(14)C]glycerol by 7 x 10(9) bacteria suspended in 10 ml of either a simple buffer system (K-36) or a complex medium (NC-5). Metabolism of the bacilli was easily detected within 3 days after inoculation and was measured daily. NC-5 medium supported metabolism of M. lepraemurium for several weeks longer than the simple K-36 buffer. The radiometric technique shows promise as a rapid and efficient system for evaluating the metabolism of mycobacteria without introducing any changes in the physiologic state of the organisms, studying their metabolic pathways, determining conditions potentially favorable for multiplication of these organisms in vitro, and studying their susceptibility to inhibition by drugs.     

A sensitive radiometric assay to measure D-xylulose kinase activity

A radiometric test system for D-xylulose kinase (XK) was developed for the measurement of enzyme activity in crude cell extracts and to minimize the volume of reaction mixtures besides increasing the sensitivity. [U-14C]xylulose 5-phosphate was produced from commercially available [U-14C]xylose in a coupled assay system containing D-xylose isomerase, which yields [U-14C]xylulose, the substrate of ATP-dependent D-xylulose kinase. Separation of products and substrates was achieved by thin layer chromatography, identification of radioactive spots by radioscanning followed by quantitative scintillation counting. The protocol was validated through determination of kinetic constants of a purified His-tagged enzyme from Escherichia coli and comparison with the spectrophotometric method. The radiometric assay was applied to determine xylulose kinase activity in crude cell extracts from a variety of eukaryotic and prokaryotic organisms.     

高分一号宽幅多光谱影像辐射定标偏差及其植被指数影响

自2013年4月在轨运行以来,高分一号(GF-1)宽幅(WFV)多光谱相机已实现持续对地观测,为包括生态学在内的相关研究领域与行业应用提供了丰富的数据源。当前场地定标频次偏低以及定标参数更新、发布滞后的现状,一定程度上影响了GF-1 WFV多光谱数据的定量应用。然而,现有文献仅在数据预处理流程中谈及对GF-1 WFV影像的辐射定标处理,很少讨论定标参数选取不当甚至误用产生的可能影响。基于已公布的辐射定标参数(2014—2021年)和4景GF-1 WFV Level1A级影像产品数据,重点围绕辐射定标偏差及其对多光谱波段星上反射率和常用植被指数的影响等展开模型分析和讨论。结果显示：即使两个相邻年份间,在多数情况下误用辐射定标参数会导致不可忽视的波段星上反射率相对偏差;进而给不同类型植被指数的实际应用带来不同程度的挑战。因辐射定标偏差的影响,常用的两波段归一化型植被指数在监测稀疏植被覆盖区时会存在明显的误差;而对高植被覆盖区的监测时采用两波段简单比值型植被指数将面临更大的挑战。针对存档GF-1 WFV Level1A数据的应用需求,提出利用时间距离加权的线性内插法来修正基于公开定标参数的辐...     

Assessment of the in vitro growth of Plasmodium falciparum using fluorometry

The growth of Plasmodium falciparum in vitro was quantitatively assessed by applying fluorometry using ethidium bromide. The fluorescence intensity of parasites stained with this dye was found to parallel the uptake of 3H-hypoxanthine into nucleic acids during one growth cycle of development. The assay system can be used as a substitute of morphological and radiometric methods in drug-sensitivity tests and for the screening of antimalarials.     

Factors involved in cell adhesion to vascular endothelium

The adhesion of blood cells to endothelium can be studied in vitro using human endothelial cells in culture. This experimental model and radiometric techniques provide us with a simple system to quantify the adhesion of blood cells to endothelium. Normal human granulocytes isolated by density gradient adhere to normal endothelial cells in a proportion of 25%. Human promyelocytic cells (HL 60) induced by retinoic acid into mature cells adhere as well as normal granulocytes while the noninduced adhere poorly to endothelium. A small percentage of normal red cells attach to endothelial cells while red cells from patients with sickle cell anemia or diabetes mellitus have a significantly increased adhesion to endothelial cells (P greater than 0.001). This adhesion is statistically correlated with the extent and severity of vascular complications in diabetes mellitus (P less than 0.05). The addition of fibrinogen significantly increased (P less than 0.01) the adhesion of normal red cells, red cells from patients with sickle cell anemia or diabetes mellitus while gamma-globulins did not modify adhesion. Fibronectin potentiated the adhesion of normal red cells.     

A comparison between the coupled spectrophotometric and uncoupled radiometric assays for RuBP carboxylase

The coupled spectrophotometric assay for RuBP carboxylase was compared with the conventional radiometric assay to assess the validity of its use in the measurement of initial and total activities in crude leaf extracts. At high magnesium concentrations both assays gave the same absolute values of initial and total activities, and resolved similarly the changes of total activity and activation state (ratio of initial to total activity) which occurred when the water status and light environment of leaves was altered prior to sampling. Although the magnesium concentration supporting the maximum rate of initial activity in soybean extracts was similar in the two assays, substantial differences of initial activity were observed at sub-optimal concentrations of magnesium. At low magnesium concentrations reaction rates in the spectrophotometric assay exhibited an initial phase of non-linearity which subsequently gave way to a linear rate. In contrast, reaction rates at low magnesium were linear from the time of initiation in the radiometric assay. Inclusion of EDTA in the reaction medium did, however, induce non-linear rates in the radiometric assay. The pre-addition of RUBP to extract immediately prior to dilution into the reaction medium did not eliminate the non-linearity in either assay system. The significance of these observations is discussed briefly in relation to the use of the spectrophotometric assay.     

表观反射率及其在植被遥感中的应用

 由于植被遥感应用定量化和监测等的需求,光学遥感数据的辐射校正更加受到重视。该文论述了辐射校正,辐射定标和大气校正的概念以及它们之间的区别及关系。特别对辐射定标的结果之一,大气层顶表观反射率,简称表观反射率(Apparent reflectance)的定义、概念、计算和它在植被遥感中的应用等方面,进行了详细的论述。     

Transponder-Aided Joint Calibration and Synchronization Compensation for Distributed Radar Systems

High-precision radiometric calibration and synchronization compensation must be provided for distributed radar system due to separate transmitters and receivers. This paper proposes a transponder-aided joint radiometric calibration, motion compensation and synchronization for distributed radar remote sensing. As the transponder signal can be separated from the normal radar returns, it is used to calibrate the distributed radar for radiometry. Meanwhile, the distributed radar motion compensation and synchronization compensation algorithms are presented by utilizing the transponder signals. This method requires no hardware modifications to both the normal radar transmitter and receiver and no change to the operating pulse repetition frequency (PRF). The distributed radar radiometric calibration and synchronization compensation require only one transponder, but the motion compensation requires six transponders because there are six independent variables in the distributed radar geometry. Furthermore, a maximum likelihood method is used to estimate the transponder signal parameters. The proposed methods are verified by simulation results.     

Identification of 6-ketoprostaglandin F1alpha formed from arachidonic acid in bovine seminal vesicles.

The prostaglandin synthesizing system in bovine seminal vesicles was characterized by a radiometric assay. Two main products were formed from [1-14C]-arachidonic acid, and their structures were confirmed by mass spectrometry. The less polar product was identical with prostaglandin E2 and the more polar one was identical with a new prostaglandin, i.e., 6-ketoprostaglandin F1alpha.     

A radiometric assay for methyl red azoreductase DT-diaphorase [EC 1.6.99.2]

A rapid radiometric assay for measuring oxygen insensitive methyl red azoreductase has been developed. [¹⁴C]Methyl red was synthesized from [U-¹⁴C]aniline; the final product had a radiochemical purity of ≥98%. [¹⁴C]Methyl red was then used as the substrate to assay azoreductase activity using a modification of a previously published procedure. Results obtained by the radiometric assay were comparable to those obtained using the fluorescent procedure. The radiometric assay is quick, simple, and reliable. Methyl red azoreductase has been shown to be identical with DT-diaphorase [EC 1.6.99.2]. The assay described can therefore be used to assay DT-diaphorase activity and does not suffer from the limitations, such as lack of specificity and low sensitivity, usually associated with DT-diaphorase assays.