Morphological diversity of cassava accessions of the south-central mesoregion of the State of Mato Grosso, Brazil.

Genetic variability of cassava (Manihot esculenta Crantz) in Brazil is wide, being this the result of natural and cultural selection during pre- and post-domestication of the species in different environments. Given the number of species of the genus found in the region (38 of a total of 98 species), the central region of Brazil was defined as the primary center of cassava diversity. Therefore, genetic diversity characterization of cassava accessions is fundamental, both for farmers and for plant breeders, because it allows the organization of genetic resources and better utilization of available genetic diversity. This research aims to assess genetic divergence of cassava accessions from the south-central region of the State of Mato Grosso, based on multi-categorical morphological traits. For this purpose, 38 qualitative and quantitative morphological descriptors were used. Genetic diversity was expressed by the genetic similarity index, with subsequent clustering of accessions by the modified Tocher's procedure and UPGMA. Of 38 descriptors, only growth habit of stem showed no variability. Tocher and UPGMA methods were efficient and corroborated on group composition. Both methods were able to group accessions of different localities in distinct group consistency.

Standardization of 223Ra by live-time anticoincidence counting and gamma-ray emission determination.

From a commercial supplier, three independent lots of an aqueous solution containing 223Ra in equilibrium with its deteriorating progeny were considered for standardization, by using live-time anticoincidence counting (LTAC) in the Laboratório Nacional de Metrologia das Radiações Ionizantes (LNMRI) Brazil. The ionization chamber calibration factors were obtained using measurements of independent lots of 223Ra in LTAC considering the absolute method in order to evaluate the constancy and reproducibility of the standardization. The calibration factors of three high-performance well-type ionization chamber systems and four commercial well-type ionization chambers were determined. The LTAC results showed that lots 2 and 3 were 1069.88 and 1097.44 kBq/kg, with corresponding relative standard uncertainties 0.12% and 0.20%, respectively. The spectrometry method results of each lot value were classified as positive by ANOVA hypothesis testing. The emission probabilities relating to the X- and γ-rays in region from 81 to 830 keV ware determined. Hence, LNMRI can provide calibration services for 223Ra.

A case review of the MRI features in alternating Tolosa-Hunt syndrome.

Tolosa-Hunt syndrome (THS) consists of a painful ophthalmoplegia with typical features in magnetic resonance imaging (MRI). The recurring nature of this affliction has been known since its first description. However, compromise of the contralateral cavernous sinus, known as alternating THS, is very rare and has never been examined using MRI. We report clinical data, laboratory data and imaging features of a patient with alternating THS. According to our literature review, this is the first MRI study of THS.

Measurement of the absolute gamma emission intensities from the decay of Th-229 in equilibrium with progeny.

There are few long-lived radionuclides yielding high intensity gamma-rays emission with energies ranging from 100 keV to 500 keV that can be applied as radioactive gamma standard to calibrate HPGe detectors. Furthermore, this energy range represents the main emitted energies of the majority of radionuclides used in nuclear medicine. The Brazilian National Laboratory for Ionizing Radiation Metrology (LNMRI/IRD/CNEN) has attempted to identify radionuclides that have the potential to be used as a calibration source due to their long half-life as well as their emission spectrum. Hence, LNMRI promotes standardization studies of gamma-emitting radionuclides that meet these criteria on order to disseminate them. Thorium-229, with its well-defined energies and relatively high intensities, is one such candidate radionuclide for the energy and full-energy peak efficiency calibration of high-purity gamma spectrometers. Thorium-229 was standardized by the method of 4παß(LS)-γ(NaI(Tl)) live timed anticoincidence counting. The emission intensities of gamma-rays associated with the decay of 229Th have been determined by HPGe gamma ray spectrometry with accuracy and precision. The results are in agreement with current literature data.

Rapid and accurate assessment of the activity measurements in Brazilian hospitals and clinics.

Traceability in Nuclear Medicine Service (NMS) measurements was checked by the Institute of Radioprotection and Dosimetry (IRD) through the Institute of Energy and Nuclear Research (IPEN). In 2016, IRD ran an intercomparison program and invited Brazilian NMS authorized to administer 131I to patients. Sources of 131I were distributed to 33 NMSs. Three other sources from the same solution were sent to IRD, after measurement at IPEN. These sources were calibrated in the IRD reference system. A correction factor of 1.013 was obtained. Ninety percent of the NMS comparisons results are within ±10% of the National Laboratory of Metrology of Ionizing Radiation (LNMRI) value, the Brazilian legal requirement.

68(Ge+Ga) activity standardization by 4πß(LS)-γ(NaI(Tl)) anticoincidence counting measurements.

In this work, a 68(Ge+Ga) solution has been standardized at the National Institute of Ionizing Radiation Metrology (LNMRI), in Brazil, in the frame of an international key comparison CCRI(II)-K2.Ge-68 piloted by National Institute of Standards and Technology (NIST/USA). The 4πß(LS)-γ(NaI(Tl)) anticoincidence method with live-time and extended dead-time was used and its result was validated by 4πß(LS)-γ(NaI(Tl)) coincidence counting and liquid scintillation counting using the Triple to Double Coincidence Ratio (TDCR) method. The deviations of the activity concentration values of coincidence and TDCR measurements from the anticoincidence result were 1.7% and 0.63%, respectively, which were within experimental evaluated uncertainties at ~95% level of confidence (coverage factor k = 2). The combined relative standard uncertainties were 0.65%, 0.70% and 0.53% for anticoincidence, coincidence and TDCR methods, respectively. These values are consistent with the results reported by Cessna at the ICRM2017 conference.

134Cs activity standardization by 4πß(LS)-γ(NaI-Tl) anticoincidence counting and submission to international reference system.

From a commercial supplier a solution containing 134Cs has been standardized at National Laboratory for Ionizing Radiation Metrology (LNMRI) for the first time using three Liquid scintillation based measurement. These measurement methods are 4πß-γ live-timed anticoincidence counting, 4πß-γ coincidence counting and 3H-standard efficiency tracing with the CNET methods. The results obtained by anticoincidence counting was adopted as reference value and its combined uncertainty was 0.38%. The agreement of this reference value with coincidence counting and CNET methods were 0.39% and 0.34% respectively and were in consistency with each uncertainty method. The weighted mean results coincidence counting and CNET methods are also in close agreement 0.03% with anticoincidence counting method and meets the requirement of primary and national standard. This standardization was made in order to reduce the uncertainty in 134Cs measurement in Brazil and also following a request made by Bureau International des Poids and Mesures for new submission to International Reference System. The LNMRI last submission was made in 1987. Therefore from a 134Cs master solution a NIST ampoules was prepared and LNMRI/IRD submitted it to the International Reference System, Bureau International of Poids and Measures (SIR/BIPM). In this paper will be analyzed the LNMRI measurement and performance each measurement methods and also take into account the reference value of KCDB, we determined also the 134Cs gamma emission probabilities of main energy.

Application of the sum-peak method to activity standardizations of 152Eu sources in LNMRI (BR).

The sum-peak method, an absolute measurement technique that uses coincidence counting and γ-ray spectrometry, was applied to activity standardization of 152Eu sources. The decay branch used was that of 152Sm, as it is almost entirely electron capture and exhibits X-rays with a high probability of coincidence with the 121.8keVgamma rays, as evidenced by the matrix technique used for complex decay schemes, a method for deriving counting rate equations describing coincidence summing of gamma and X-rays. The result was compared with the calibration performed by ionization chamber traceable to BIPM. The results presented uncertainty values of 0.50% (k = 1).

Results of an international comparison of activity measurements of 68Ge.

An international key comparison, identifier CCRI(II)-K2.Ge-68, has been performed. The National Institute of Standards and Technology (NIST) served as the pilot laboratory, distributing aliquots of a 68Ge/68Ga solution. Results for the activity concentration, CA, of 68Ge at a reference date of 12h00 UTC 14 November 2014 were submitted by 17 laboratories, encompassing many variants of coincidence methods and liquid-scintillation counting methods. The first use of 4π(Cherenkov)ß-γ coincidence and anticoincidence methods in an international comparison is reported. One participant reported results by secondary methods only. Two results, both utilizing pure liquid-scintillation methods, were identified as outliers. Evaluation using the Power-Moderated Mean method results in a proposed Comparison Reference Value (CRV) of 621.7(11)kBqg-1, based on 14 results. The degrees of equivalence and their associated uncertainties are evaluated for each participant. Several participants submitted 3.6mL ampoules to the BIPM to link the comparison to the International Reference System (SIR) which may lead to the evaluation of a Key Comparison Reference Value and associated degrees of equivalence.

A preliminary study revealing a new association in patients undergoing maintenance hemodialysis: manganism symptoms and T1 hyperintense changes in the basal ganglia.

BACKGROUND AND PURPOSE: Patients undergoing parenteral nutrition and those with portosystemic encephalopathy secondary to chronic liver disease and acquired and congenital portosystemic venous shunts frequently present manganese deposition in the basal ganglia, detected by MR imaging as hyperintense areas on T1-weighted sequences. We also observed similar abnormalities in the basal ganglia of patients with chronic renal failure undergoing maintenance hemodialysis. Our aim was to evaluate the pallidal signal intensity on T1-weighted images in a series of patients undergoing hemodialysis, with further evaluation of serum manganese levels and neurologic correlation, comparing them with patients with chronic renal failure without dialytic treatment. MATERIALS AND METHODS: We performed MR imaging examinations in 9 patients with chronic renal failure, 5 of whom were undergoing hemodialysis. An experienced neuroradiologist scrutinized the presence of symmetric hyperintensities in the basal ganglia on T1-weighted sequences. We also determined the serum manganese levels and performed the neurologic evaluations in all patients. RESULTS: All patients undergoing hemodialysis presented elevated serum manganese levels and symmetric hyperintensities within the globus pallidus. In this group, 4 patients presented with parkinsonian symptoms, myoclonus, and syndromes with vestibular and vestibular-auditory symptoms. The patients without dialytic treatment presented with neither bilaterally increased T1 MR imaging signal intensity within the globus pallidus nor symptoms of manganism. CONCLUSION: Our preliminary results demonstrated the occurrence of bilateral pallidal hyperintensity on T1-weighted images in all patients undergoing hemodialysis associated with high serum manganese levels, revealing a new association.

Motor neuron disease associated with non-fluent rapidly progressive aphasia: case report and review of the literature.

The superimposed clinical features of motor neuron disease (MND) and frontotemporal lobar degeneration (FTLD) comprise a rare neurological overlap syndrome that represents a diagnostic challenge to neurologists. Currently, FTLD-MND is considered a distinct entity and its clinicopathological basis has recently been reviewed. Our aim is to present a patient with MND and non-fluent rapidly progressive aphasia with clinical, imaging and histopathological correlation, as well as a brief review of the literature. We demonstrated the selective corticospinal tract (CST) and temporal lobe involvement using T1 spin-echo with an additional magnetization transfer contrast pulse on resonance (T1 SE/MTC) and FLAIR MR sequences in our patient, with further clinical and histopathological correlation. To the best of our knowledge, there is no description about the use of these particular MR sequences in the evaluation of FTLD-MND patients.

Standardization of 106Ru/Rh by live-timed anticoincidence counting and gamma emission determination.

The absolute activity standardization measurement system of radionuclide by live-timed anticoincidence counting was implemented at LNMRI in 2008 to reduce the effects of some correction factors on the determination of activity with coincidence counting technique used for decades in the laboratory, for example, the corrections of dead time and resolution. With the live-timed anticoincidence system, the variety of radionuclides that can be calibrated by LNMRI was increased in relation to the type of decay. The objective of this study was to standardize the 106Ru activity, determine gamma emission probabilities by spectrometric method for some energies, and estimate measurement uncertainties.

Standardization and decay data determinations of 125I, 54Mn and 203Hg.

The absolute 4pi-betagamma coincidence counting has been used to measure the activity concentrations of 54Mn and 203Hg, and the Sum-Peak method was used for 125I. 54Mn and 125I radionuclides have been part of international key-comparisons coordinated by the Bureau International des Poids et Measures (BIPM) in 2003/2004, while 203Hg is part of the traceability programme of the National Laboratory for Ionizing Radiation Metrology (LNMRI)/Brazil. Three different detectors were used for the Sum-Peak method: 3''x3'' NaI(Tl) and 5''x5'' well NaI(Tl) scintillation detectors and a planar germanium detector. Direct measurements were made of the photon emission probabilities of the 35.5-, 834.8- and 279.2-keV gamma-rays of 125I, 54Mn and 203Hg to give values of (0.0667+/-0.0014), (0.9997+/-0.0055) and (0.8161+/-0.0005), respectively. The half-lives of 203Hg and 54Mn were also determined by means of a 4pigamma ionization chamber (203Hg) and by the reference source method using a HPGe detector (54Mn) to give values of (46.639+/-0.023) days and (312.1+/-0.9) days, respectively.

Absolute standardization of the impurity (121)Te associated to the production of the radiopharmaceutical (123)I.

(123)I is widely used for radiodiagnostic procedures. It is produced by reaction of (124)Xe (p,2n) (123)Cs →(123)Xe →(123)I in cyclotrons. (121)Te and (125)I appear in a photon energy spectrum as impurities. An activity of (121)Te was calibrated absolutely by sum-peak method and its photon emitting probability was estimated, whose results were consistent with published results.

Evaluation of the toxic activity of anorectic diethylpropion in Chinese hamster ovary cells.

Diethylpropion has been available in the market for treating obesity for over 50 years. Refined studies are lacking to fully elucidate its action spectrum. The aim of our study was to evaluate possible toxic effects of anorectic diethylpropion in Chinese hamster ovary (CHO) cells. Comet assay (detects breaks in the DNA strand), micronucleus test (detects clastogenic/aneugenic damage), and cell survival test (detects cytotoxic damage) were used to evaluate the toxic effects. In comet assay, we found that the damage scores with diethylpropion treatments at the concentrations of 20 and 40 µg/mL were more significant ( p < 0.05) than that of the negative control. When assessing the possible aneugenic and/or clastogenic damage caused by the drug in CHO cells, we found no difference ( p > 0.05) in the values of micronucleated cells when comparing different diethylpropion treatments and the negative control. Regarding the cell viability, for all the diethylpropion concentrations tested, higher values ( p < 0.05) of apoptosis were found compared with those of the negative control. In relation to the number of necrotic cells, no difference ( p > 0.05) was noted between the means of the three concentrations of diethylpropion evaluated and the negative control. In the experimental conditions, we conclude that diethylpropion has weak genotoxic and cytotoxic activities.

Epidemiology of snakebite in a central region of Brazil.

The aim of this article is to acquire knowledge about the aspects of snakebite epidemiology in a central region of Brazil. From 1993 to 1995, 90 cases of Crotalinae (Bothrops and Crotalus genera) and two cases of Micrurus snakebite were attended to in a general hospital. Epidemiological information about 73 out of the 90 Crotalinae victims was prospectively collected from interviews with the patients and/or their companions. Data from medical records were obtained for the 17 remaining cases. The snakes of Bothrops, Crotalus, and Micrurus genera were responsible for 74, 24 and 2% of the accidents, respectively. Most of the Crotalinae accidents occurred from October to March (68%) and from 06:00 to 12:00 a.m. (93%). Males (89%) and patients between 20 and 30 years-old (27%) were the most common victims. The main bite sites were: foot (24%), leg (23%), hand (22%) and ankle (21%). Among the 73 interviewed Crotalinae victims, farm workers were bitten more frequently (53%). The accidents often occurred during work (59%), and 90% of the patients wore footwear, but 30% were wearing only sandals. Tourniquet, squeezing, suction of the bite site and magic blessing were attempted in 47, 38, 8 and 10% of cases, respectively.

Considerations related to the decontamination of houses in Goiânia: limitations and implications.

We are considering some aspects related to the decontamination activities of about 50 houses affected by 137Cs in Goiânia. We describe the way these contaminations occurred, the instruments used, and the procedures. We also discuss the dose limits established for decontamination and the consequences resulting from this action. We call attention to the importance of not only the technical aspects in such activities but also the psychosocial implications resulting from them.

Absolute measurements of photon emission probabilities of 169Yb.

A solution of 169Yb was absolutely standardized by the 4pi(EC,X)-gamma coincidence counting method and the result was used to obtain direct measurements of gamma-ray emission probabilities with a coaxial HPGe detector. The empirical relation proposed by (Vaño, F., Gonzalez, L., Gaeta R., Gonzalez, J.A., 1975. An empirical function which relates the slope of the Ge efficiency curves and the active volume Nucl. Instr. Meth. 123, 573) was tested using the gamma spectral response above 200 keV. The half-life of 169Yb was also measured with a 4pi gamma ionization chamber.

Intercomparison of 131I and 99mTc activity measurements in Brazilian nuclear medicine services.

This work outlines the quality assurance program for the activity measurements of the most used radionuclides at Brazilian Nuclear Medicine Services (NMS). The program aims to guarantee that the patient is given the correct prescribed amount of activity in diagnostic or therapeutic applications. This accurate administration depends upon proper use and calibration of the activity meters by the NMS. Underestimation of administered activity in diagnostic practices could delay correct diagnosis disturbing the value of the investigation. On the other hand, the overestimation would be worse, mainly in therapeutic applications, because an unnecessarily high absorbed dose would be delivered to the patient. The preliminary results of intercomparison for 131I and 99mTc showed that many activity meters used at NMS's present problems giving results up to 41% greater than the reference values determined at the National Metrology Laboratory for Ionizing Radiation (LNMRI) which is recognized as the Brazilian authorized metrology laboratory for ionizing radiation. These results have demonstrated that the NMS should improve the accuracy of the activity measurements of the radionuclides administered to the patients and establish the traceability to the national standards of measurements. These standards are based on a pressurized well-type ionization chamber installed at LNMRI and calibrated with reference sources standardized by absolute methods. The protocol of the intercomparison and recommendations made in order to minimize errors in measuring procedures are described and results are discussed.

Performance of dose calibrators in Brazilian hospitals for activity measurements.

In order to obtain information on the accuracy of activity measurements in Brazilian hospitals, several intercomparison exercises have been organized since 1998. The first exercise consisted of two intercomparison runs of 131I and 99mTc and had the participation of 21 hospitals localized in Rio de Janeiro city and surroundings. The second, with 131I (47 hospitals) and 123I (12 hospitals), had the participation of hospitals localized in the whole country. The results were analyzed under the statistical point of view and conformity to the norms of Regulatory Authority. These results have shown that such exercises are necessary to improve the quality of the measurements and to identify those instruments that are producing incorrect values.