Assessment of the neutron radiation field with activation foils and intermittent irradiations around a PETtrace biomedical cyclotron.

This work aimed at assessing the neutron radiation field with activation foils around of the PETtrace biomedical cyclotron. Activation foils of gold, gold covered with cadmium, indium and nickel was used to evaluate the thermal, epithermal and fast neutron contributions, respectively. The irradiations of the activation foils were performed using the intermittent irradiation method to conciliate the measurements with the routine 18F production. The evaluated points showed the contributions of the thermal, epithermal and fast neutrons due to interaction with the vault room, cyclotron accelerator and main cyclotron components.

EXPERIMENTAL EVALUATION OF NEUTRON SHIELDING MATERIALS.

A new proposed design of neutron shielding material-based on the commercial material Borotron UH050 with an addition of Al(OH)3-is evaluated in order to determine if its neutron and gamma shielding properties match those of a reference material, NS4FR. Neutron and gamma dosimetry measurements are performed, as well as neutron spectrometry measurements and Monte Carlo simulations. Negligible differences are found between the materials for neutron shielding, while significant differences are found for gamma shielding. The effect of Al(OH)3 addition to Borotron UH050 is to reduce neutron shielding properties while increasing gamma shielding properties. The resulting material is as efficient as NS4FR for neutron shielding but less efficient for gamma shielding-thicknesses 20% higher are required to match gamma shielding properties of NS4FR. Monte Carlo models of the materials are validated based on the performed measurements of neutron spectra and neutron and gamma ambient dose equivalent.

Índice de normalidade da distância atlantoaxial dorsal em cães / Normal index of dorsal atlantoaxial distance in dogs

Foram utilizados 30 cães neurologicamente saudáveis e realizadas radiografias da coluna cervical, sendo mensurada a menor distância atlantoaxial dorsal e outros parâmetros anatômicos vertebrais. Esses dados foram avaliados por meio do coeficiente de correlação de Pearson. Após detecção do melhor parâmetro de correlação, utilizou-se a fórmula de coeficiente de correlação dimensional (CCD). Na segunda etapa desta pesquisa, foram utilizadas imagens radiográficas de 33 cães com subluxação atlantoaxial (SAA) e aplicou-se a fórmula CCD. Todas as imagens atlantoaxiais normais e subluxadas foram distribuídas aleatoriamente e submetidas à análise subjetiva. Observou-se que o parâmetro anatômico de maior correlação foi o comprimento do processo espinhoso do áxis, obtendo-se valor de índice médio de 0,056 e desvio-padrão de 0,019. O valor de índice médio obtido em cães com SAA foi de 0,287, e o desvio-padrão de 0,123. A análise subjetiva revelou acerto de 88,89% a 95,24%, enquanto a avaliação por meio da fórmula CCD demonstrou ser 100% eficiente no diagnóstico da SAA. Sugeriu-se a utilização da fórmula CCD para obtenção do índice de normalidade da distância atlantoaxial com valor de normalidade médio de 0,056 e limite máximo de 0,098, sendo esse índice eficaz no diagnóstico da subluxação entre o atlas e o áxis.(AU)

Thirty healthy dogs had their cervical spines radiographed, and the dorsal atlantoaxial distance and others vertebral anatomical parameters were measured. These data were assessed using the Pearson correlation coefficient. After detection of the best correlation parameter, we used the dimensional correlation coefficient of formula (CCD). In the second stage of the study, radiographs of the 33 dogs with atlantoaxial subluxation (SAA) were used. In each radiographic image, the CCD formula was applied. All normal and subluxation radiographic images were randomized, and submitted to subjective analysis. It was observed that the anatomical parameter with the highest correlation is the length of the spinous process of the axis, obtaining a mean value of 0.056 index and 0.019 standard deviation. Index mean value obtained in dogs with the disease of 0.287 and standard deviation of 0.123. The subjective analysis revealed 88.89% to 95.24% agreement, while the result obtained by the CCD formula was shown to be 100% effective in the diagnosis of SAA. We suggest the use of the CCD formula to obtain the index of normality of the atlantoaxial distance with a mean value of 0.056 and maximum of 0.098, and it is concluded that the index is highly effective in the diagnosis of subluxation between the atlas and the axis.(AU)

Ramos do arco aórtico e da aorta torácica em bicho-preguiça (Bradypus variegatus) / Branches of the aortic arch and thoracic aorta of the sloth (Bradypus variegatus)

As preguiças são mamíferos arborícolas, bem específicos quanto aos hábitos e à morfofisiologia. Essa condição faz delas ainda mais vulneráveis aos impactos ambientais. Com o objetivo de fornecer informações que auxiliem na clínica médico-cirúrgica desses Xenarthras, realizou-se um estudo do arco aórtico e da artéria aorta torácica, a fim de se identificarem seus principais ramos. Foram utilizados 10 animais da espécie Bradypus variegatus, sendo uma fêmea e três machos submetidos a dissecação, por meio da qual foram obtidas medidas de diâmetro e comprimento dos vasos, enquanto três fêmeas e três machos destinaram-se à técnica de radiografia digital com contraste. Constatou-se uma sintopia uniforme do arco, bem como da porção descendente da artéria aorta no tórax. No entanto, a topografia difere consideravelmente. Com base nos ramos, percebeu-se, independentemente do sexo, uma maior variação naqueles originados do arco e dos que emergem da artéria aorta torácica e irrigam estruturas medianas e do antímero direito do tórax. Foram obtidos valores maiores para o diâmetro das artérias na fêmea do que nos machos e, para o comprimento da artéria aorta torácica, foram encontrados valores correspondentes em ambos. Toda essa variação dos bradipodídeos apresenta diferenças em relação a outros mamíferos.(AU)

Sloths are arboreal mammals, very specific, regarding their habits and morphology. This condition makes them even more vulnerable to environmental impacts. In order to provide information to assist in the medical and surgical assistance to these Xenarthras, a study of the aortic arch and thoracic portion of the descending aorta was carried out with the purpose of identify its main branches. Ten animals of the Bradypus variegatus species were used. One female and three males were submitted to dissection, where measurements of vessel diameter and length were obtained, while three females and three males were submitted to the digital contrast x-ray technique. There was a uniform syntopy of the arch, as well as of the descending portion of the aorta in the thorax. However, the topography differs considerably. Based on the branches, regardless of gender, a greater variation was observed in those originating from the arch, and those that emerge from the thoracic aorta and irrigate medial structures and the right antimere of the thorax. Greater values were obtained for the diameter of the arteries in the female than in the males and corresponding values for the length of the thoracic aorta in both. All this variation is possibly related to the adaptive processes of Bradipodidae over time.(AU)

Neutron spectra due (13)N production in a PET cyclotron.

Monte Carlo and experimental methods have been used to characterize the neutron radiation field around PET (Positron Emission Tomography) cyclotrons. In this work, the Monte Carlo code MCNPX was used to estimate the neutron spectra, the neutron fluence rates and the ambient dose equivalent (H*(10)) in seven locations around a PET cyclotron during (13)N production. In order to validate these calculations, H*(10) was measured in three sites and were compared with the calculated doses. All the spectra have two peaks, one above 0.1MeV due to the evaporation neutrons and another in the thermal region due to the room-return effects. Despite the relatively large difference between the measured and calculated H*(10) for one point, the agreement was considered good, compared with that obtained for (18)F production in a previous work.

Use of the MCNPX to calculate the neutron spectra around the GE-PETtrace 8 cyclotron of the CDTN/CNEN, Brazil.

The Monte Carlo code MCNPX was used to calculate the neutron spectra in 4 points around the targets of the CDTN/CNEN cyclotron, Belo Horizonte, Brazil, during the production of the (18)FDG. Simulated data were compared with experimental data obtained with a Bonner multisphere spectrometry system (BSS) using TLD-600 and TLD-700 and the unfolding codes BUNKIUT, BUMS and NSDUAZ. In general, simulated spectra disagreed with those obtained by experimental means by a factor as high as 14. Measurements performed with a doserate meter in other 3 more shielded points, showed also an overestimation of the ambient dose equivalent rate by a factor as high as 20 in comparison with simulated results. Results are not conclusive and a more refined study is necessary. However, neutron emission rate of the source-term of radiation must be investigated and an special caution must be taken in the experimental measurements, by discriminating of the target selected for the irradiations and utilizing a matrix response suitable for the passive detectors (e.g. TLD) utilized in the experiments, instead of a matrix response (e.g. UTA4) developed for scintillation detectors.

Use of a TLD-based multisphere spectrometry system to measure the neutron spectra around a not-self-shielded PET cyclotron: Preliminary results.

In the present work, we utilized the BSS system with TLD-600 and TLD-700 to measure the neutron spectra around the GE-PETtrace 8 cyclotron of the Development Centre of Nuclear Technology (CDTN/CNEN) in Belo Horizonte, Brazil. The cyclotron is capable of accelerating protons up to 16.5 MeV, to production of fluorine-18. Four points inside the bunker of the cyclotron were studied. Two points in front of the primary radiation beam and other two opposed to the primary radiation beam. The measurements were unfolded with the BUMS and the NSDUAZ computer codes. The dosimetric quantities obtained were in agreement with the other published data and were coherent with the expected from theoretical estimates obtained from source term informed by the manufacturer of the cyclotron.

Farmacodermia em um cão após administração de antibióticos do grupo betalactâmico: relato de caso / Pharmacodermia in a dog after administration of beta-lactam antibiotics: case report

A severe cutaneous reaction in a female dog after administration of penicillin and cephalexin is described, in which the main signs presented by the patient were fever, lack of appetite, and detachment of epidermis in the dorsal region of body.The established treatment was surgical debridement of the region, topical application of Aloe Vera with sugar, and systemic antibiotic therapy with ciprofloxacin, resulting in the recovery and wound closure in approximately 45 days.

Demographic and anthropometrical analysis and genotype distribution of chronic hepatitis C patients treated in public and private reference centers in Brazil

Hepatitis C virus (HCV) infection is a serious public health problem, since 80 percent to 85 percent of HCV carriers develop a persistent infection that can progress into liver cirrhosis and hepatocarcinoma. Considering that the response of hepatitis C patients to combination therapy with interferon and ribavirin depends on HCV characteristics as well as on host features, we made a retrospective analysis of demographic and anthropometrical data and HCV genotype distribution of chronic hepatitis C patients treated in public and private reference centers in Brazil. The medical records of 4,996 patients were reviewed, 81 percent from public and 19 percent from private institutions. Patients' median age was 46 years, and there was a higher prevalence of male (62 percent) and white patients (80 percent). The analysis of HCV-infecting strains showed a predominance of genotype 1 (64 percent) over genotypes 2 and 3. The patients' mean weight was 70.6 kg, and 65 percent of the patients weighed less than 77kg. Overweight and obesity were observed in 37.8 percent and 13.6 percent of the patients, respectively. Since a body weight of 75 kg or less has been considered an independent factor that significantly increases the odds of achieving a sustained virological response, the Brazilian population seems to have a more favorable body weight profile to achieve a sustained response than the American and European populations. The finding that 65 percent of chronic hepatitis C patients have a body weight of 77 kg or less may have a positive pharmacoeconomic impact on the treatment of genotype 1 HCV patients with weight-based doses of peginterferon.

Demographic and anthropometrical analysis and genotype distribution of chronic hepatitis C patients treated in public and private reference centers in Brazil.

Hepatitis C virus (HCV) infection is a serious public health problem, since 80% to 85% of HCV carriers develop a persistent infection that can progress into liver cirrhosis and hepatocarcinoma. Considering that the response of hepatitis C patients to combination therapy with interferon and ribavirin depends on HCV characteristics as well as on host features, we made a retrospective analysis of demographic and anthropometrical data and HCV genotype distribution of chronic hepatitis C patients treated in public and private reference centers in Brazil. The medical records of 4,996 patients were reviewed, 81% from public and 19% from private institutions. Patients' median age was 46 years, and there was a higher prevalence of male (62%) and white patients (80%). The analysis of HCV-infecting strains showed a predominance of genotype 1 (64%) over genotypes 2 and 3. The patients' mean weight was 70.6 kg, and 65% of the patients weighed less than 77 kg. Overweight and obesity were observed in 37.8% and 13.6% of the patients, respectively. Since a body weight of 75 kg or less has been considered an independent factor that significantly increases the odds of achieving a sustained virological response, the Brazilian population seems to have a more favorable body weight profile to achieve a sustained response than the American and European populations. The finding that 65% of chronic hepatitis C patients have a body weight of 77 kg or less may have a positive pharmacoeconomic impact on the treatment of genotype 1 HCV patients with weight-based doses of peginterferon.

[Amantadine-HCL in the treatment of chronic hepatitis C in non-responders to alpha-interferon. Effect on ALT serum levels and viral load]. / Cloridrato de amantadina no tratamento de portadores de hepatite crônica C não-respondedores ao alfa-interferon. Efeito sobre os níveis séricos de ALT e carga viral.

Due to the limited efficacy of alpha-interferon for chronic hepatitis C amantadine has been proposed as a possible alternative method of treatment. However, few studies about efficacy of amantadine in chronic hepatitis C are available with controversial results. Stimulated by recent data in the literature, we studied the effect of 100 mg of amantadine HCL (alone) PO bid, for a four month period on alanine aminotransferase serum levels and viral load in a cohort of 18 patients (14 males and 4 females) with chronic hepatitis C, non-responders to alpha-interferon. Inclusion criteria were: detectable serum HCV-RNA, alanine aminotransferase above the upper limit of normal, chronic inflammation on liver biopsy, no other associated chronic liver disease and written informed consent. Available biopsies showed initially four cases of cirrhosis, six of chronic persistent hepatitis and eight of chronic active hepatitis. The most prevalent HCV genotypes were 3a (n = 9, 52.94%) and 1b (n = 6, 32.29%). Viral load (Amplicor HCV Monitor, Roche, USA) and alanine aminotransferase levels were obtained at baseline and after four months of treatment. All patients enrolled into the study but one completed the treatment. One patient discontinued amantadine due to severe depression. No significant reduction was observed between baseline and final values of alanine aminotransferase (139.118 +/- 79.789 vs. 99.588 +/- 62.583 U/L, P = 0.059) and viral load (7.154 +/- 1.596 vs. 6.574 +/- 1.584 log copies/mL, P = 0.147). Amantadine alone was not effective neither eradicating viremia nor normalizing alanine aminotransferase levels in chronic hepatitis C non-responders to alpha-interferon patients. It is suggested that only a study with amantadine alone in-patients without previous treatments could determine its efficacy in comparison with alpha-interferon.

Cholestasis secondary to Hodgkin's disease: report of 2 cases of vanishing bile duct syndrome.

Only a small percentage of patients with Hodgkin's disease become clinically Jaundiced during their disease. This Jaundice may be secondary to biliary obstruction, hemolysis, direct hepatic infiltration by the disease, drug toxicity or viral hepatitis. Vanishing bile duct syndrome secondary to Hodgkin's disease is a rare cause of cholestasis in these patients, only 13 cases having been reported so far. The authors describe 2 patients who developed severe Jaundice secondary to Hodgkin's disease due to vanishing bile duct syndrome affecting small intrahepatic bile ducts.

Relationship between biliary and serum bile acids and response to ursodeoxycholic acid in patients with primary biliary cirrhosis.

OBJECTIVE: Ursodeoxycholic acid (UDCA) improves liver biochemistries and enriches the bile with UDCA in patients with primary biliary cirrhosis. The aim of this study was to determine whether the degree of enrichment of bile correlated with that of serum and whether either of these measures correlated with improvement in measures of liver disease. METHODS: In a randomized study, biliary and serum bile acid analyses were performed at entry and after 2 yr of UDCA or placebo. RESULTS: The percentage of ursodeoxycholic acid in bile increased by 42% in the UDCA group (n = 61) compared with 8% in the placebo group (n = 57) (p < 0.0001). Measurement of serum bile acids in 32 patients (18 ursodeoxycholic acid, 14 placebo) indicated that at 2 yr, ursodeoxycholic acid comprised 65% of serum bile acids in the treated group and 7% in the placebo group. Agreement between bile and serum was fair (r = 0.75, p < or = 0.00002) because in some patients, plasma but not biliary bile acids were enriched with UDCA. Changes in biliary ursodeoxycholic acid correlated significantly but weakly with the changes in serum alkaline phosphatase, AST, bilirubin, and in Mayo risk score. Correlations between changes in serum bile acid composition and biochemical measures of disease activity were even weaker. CONCLUSION: The measurement of biliary bile acids is superior to that of serum bile acids for assessing the compliance and changes in the circulating bile acids in patients receiving ursodeoxycholic acid for the treatment of primary biliary cirrhosis. Furthermore, measures to further increase the proportion of ursodeoxycholic acid in circulating bile acids should be explored.

Custo do transplante hepático no Hospital de Clínicas da Universidade Federal do Paraná / Cost of liver transplantation at the Clinical Hospital of Parana, Brazil

Objetivo. Determinar o custo do transplante hepático no Hospital de Clínicas da Universidade Federal do Paraná. Método. Os dados do prontuário de 24 pacientes submetidos a 25 transplantes hepáticos foram avaliados do dia da internaçao para o transplante hepático até a data da alta hospitalar ou óbito para determinar o número de dias de internaçao, o local de internaçao, a quantidade de material e medicamentos usados, os exames complementares e procedimentos realizados. Honorários médicos nao foram incluídos no estudo. Resultados. A idade dos pacientes variou de 6 a 56 anos, tendo seis deles menos que 14 anos de idade. Cinco pacientes foram a óbito durante a internaçao hospitalar. Retransplante foi realizado em somente um paciente. O custo médio da retirada do fígado do doador foi de US$ 2,783.19. O custo total do transplante hepático variou amplamente entre os pacientes, na dependência de ocorrência de complicaçoes pós-operatórias, do número de dias de internaçao hospitalar e da quantidade de transfusao de hemoderivados. O custo total variou de US$ 6,359.84 a US$ 75,434.18, com média de US$ 21,505.53. O item mais caro do transplante hepático foi o custo com a hemoterapia, seguido do custo com medicamentos e diária hospitalar. Conclusao. O custo do transplante hepático varia muito entre os pacientes e pode ser realizado no Brasil a um custo inferior ao relatado nos Estados Unidos e na Europa.

[Cost of liver transplantation at the Clinical Hospital of the University of Parana, Brazil]. / Custo do transplante hepático no Hospital de Clínicas da Universidade Federal do Paraná.

PURPOSE: To determine the cost of liver transplantation at the Clinical Hospital of the Federal University of Parana. METHODS: The data of 24 patients subjected to 25 liver transplantations were evaluated from the day of hospital admission until the day of discharge to determine the length of hospitalization, quantity of material and medications used, and exams and procedures performed. Professional fees were not included in the study. RESULTS: The age of the patients varied from 6 to 56 years. Six patients were younger than 14 years of age. Five patients died during hospitalization. Retransplantation was performed in only one patient. The average cost for liver procurement was US$ 2,783.19. The total cost of the liver transplantation varied, depending on the occurrence of complications, length of hospitalization and the amount of blood products transfused. The total cost varied from US$ 6,359.84 to US$ 75,434.18, with an average of US$ 21,505.53. The most expensive item of the liver transplantation was blood products transfused, followed by medications, and intensive care and room charges. CONCLUSIONS: The cost of liver transplantation varies among the patients and may be performed in Brazil at a cost less than that reported in the United States and Europe.

Hepatic levels of cyclosporine and metabolites in patients after liver transplantation.

Despite the critical role of the liver in the metabolism of cyclosporine, only a few studies have measured hepatic levels (CSAH) in patients receiving the drug, and none has directly assayed hepatic levels of the metabolites. In this study we measured CSAH and its principal metabolites (mono-OH and di-OH CSA) by HPLC/mass spectroscopy in 19 liver biopsy specimens collected from 14 patients who had undergone liver transplantation, in order to determine how they correlated with blood levels (CSAB). The hepatic concentrations were also compared with biochemical and histological parameters of cholestasis. A positive correlation was observed between CSAH and CSAB (r = 0.47), irrespective of the length of time the patients had received the drug (7 to 1662 days) as defined by the relationship: CSAH(ng/g wet weight) = 6.7 x CSAB(ng/ml)+338. Hepatic levels of metabolites exceeded those of the parent compound in 11 biopsy specimens. No correlation was found for CSAH and the metabolites and serum bilirubin or the degree of cholestasis in the liver biopsy specimens. These findings indicate that: (1) CSA is concentrated in liver tissue several-fold over blood; (2) The hepatic concentration can be estimated from the blood concentration even in the presence of cholestasis; (3) Significant levels of CSA metabolites are found in liver tissue, frequently exceeding the concentration of the parent compound.

Antimitochondrial antibody-negative primary biliary cirrhosis.

OBJECTIVES: We reviewed our experience with patients who had biochemical and histological features of primary biliary cirrhosis in the absence of antimitochondrial antibodies (AMA) to better understand this variant of the syndrome. METHODS: During the period between 1976 to 1992, 597 patients with clinical and histological features of primary biliary cirrhosis were seen at the Mayo Clinic. Thirty-five (5.8%) of these patients were negative for antimitochondrial antibody and had normal cholangiographic studies. The records of these patients were reviewed for this study. RESULTS: No difference was found between the two groups with respect to age, gender, or biochemical features. IgM and gamma-globulin levels were higher in the antimitochondrial antibody-positive than the antimitochondrial antibody-negative patients. What is more important, 96% of the AMA-negative patients who could be tested were positive for antinuclear antibody or anti-smooth-muscle antibodies. These tests were positive in only 56% of the antimitochondrial antibody-positive group (p < 0.05). The response of five of these patients to ursodeoxycholic acid appeared comparable to the response seen in antimitochondrial antibody-positive patients. CONCLUSIONS: Patients with histological features of primary biliary cirrhosis, whether antimitochondrial antibody positive or negative, are quite comparable with respect to clinical and biochemical features. Other autoantibodies, such as antinuclear or anti-smooth-muscle antibodies, are more common in the antimitochondrial antibody-negative group. These two conditions might be part of a spectrum that has been termed "autoimmune cholangitis" and that is characterized by chronic cholestasis, histological features of chronic nonsuppurative destructive cholangitis, and the presence of any of a variety of serum autoantibodies.