Dose Optimization in Lumbar Spine Radiographic Examination by Air Gap Method at CR and DR Systems: A Phantom Study.

OBJECTIVE: This study aims at investigating the feasibility of replacing an antiscatter grid with an air gap to achieve dose reduction for lumbar spine radiography while retaining image quality at an acceptable diagnostic level. METHODS: Frontal and lateral projections of lumbar spine radiographic examinations were performed on an anthropomorphic phantom. Nongrid images of both the computed radiography (CR) and digital radiography (DR) systems with air gap thickness ranging from 0 to 25 cm were produced and compared with their corresponding grid images. Dose measurements using thermoluminescent dosimeters at the ovary and testes regions of the phantom were conducted. The image quality of all the images was evaluated by five radiographers using image quality score and visual grading analysis tests. Data on dose measurements and image quality tests were input for statistical analysis. The dose area product (DAP) of all the examinations was recorded and input for the computation of effective doses using a PC-based Monte Carlo program (PCXMC 2.0; STUK, Helsinki, Finland). RESULTS: Significant dose reduction effects on the ovaries of 60.2%-74.1% and 55.1%-73.3% were found, respectively, at the frontal and lateral projections of nongrid lumbar spine examinations compared with their corresponding grid ones in both the CR and DR systems. Results on the image quality score and visual grading analysis tests showed that nongrid images with 10-cm and 5-cm of air gap thicknesses respective to the frontal and lateral images of the lumbar spine were rated with the highest scores. In general, a dose reduction effect using the air gap method was found to be more pronounced in the CR system compared with the DR system. Nevertheless, the CR system delivered a 2.4-4.5 times higher ovary dose respective to the frontal and lateral projections of lumbar spine examinations compared with the DR system. CONCLUSIONS: Ten and 5 centimeters were found to be the optimal air gap thicknesses respective to the frontal and lateral lumbar spine radiographic examinations of the tested Rando phantom (Alderson Laboratories, Stamford, CT) in both the CR and DR systems. Significant dose reduction effects on both the ovary and testes regions of the nongrid examinations were shown. The effective dose computed from PCMCX 2.0 reflected that the risk of cancer induction was halved when an antiscatter grid was replaced by the nongrid method with an optimal air gap thickness in the tested examinations. Further reduction on cancer risk could be achieved by using DR instead of the CR system.

Transarterial ethanol ablation of cirrhotic liver with lipiodol-ethanol mixture: safety and efficacy study in rats.

PURPOSE: The intra-arterial administration of lipiodol-ethanol mixture (LEM, mixed in 4:1 by volume) through the hepatic artery is known to produce dual hepatic-arterial and portal-venous embolization that could be a potent treatment of hepatocellular carcinoma. The aim of this animal experiment was to study the effectiveness and safety of such transarterial ethanol ablation in cirrhotic livers. METHODS: The study model consisted of a control group of 6 normal rats and a study group of 6 cirrhotic rats. LEM was infused intra-arterially into the right lobe of all 12 rats after selective catheterization under microscopic observation. LEM distribution within the hepatic vasculature, liver function tests, change in liver volume, and histology of the embolized lobe were studied. RESULTS: The radiographs showed peripheral distribution of LEM within the portal venule in the right lobe of all rats. There was a marked reduction in the volume of right lobe 14 days after LEM, with an average reduction of 63.4 +/- 16.9% and 59.4 +/- 20.6% observed in the control group and study group, respectively. The difference between the 2 groups was not statistically significant. Before LEM treatment, there was a difference between the 2 groups (P = 0.002) regarding the plasma level of albumin and bilirubin, indicating that the blood test was sensitive enough to differentiate the liver function status between the normal rats and cirrhotic rats. On day 14, there was no difference between the 2 groups in plasma albumin, bilirubin, and ALT levels (P = 0.065, 0.818, 0.589), indicating almost equal extent of hepatic reaction towards LEM administration in normal and cirrhotic rats. On day 14, histologic study showed complete vascular infarction in 90% to 100% of the right lobe in both groups. CONCLUSION: Intraarterial ethanol ablation with LEM is equally effective in causing infarction of hepatic tissue in both normal and cirrhotic liver; it can be tolerated with equal safety by both normal and cirrhotic rats in this animal experiment.

A survey of dairy cattle worm control practices in southeast Brazil.

A survey on the nematode control strategies utilized by dairy farmers in Southeastern Brazil, a region accounting for 46.4% of the national milk production, was conducted through interviews with farmers. To select the producers to be interviewed the region was split into 16 non-contiguous clusters, according to the level of milk production. A systematic sample was then selected in each of the clusters. The interview questionnaire consisted of one-way, multiple-choice and open-ended questions. Data collected were represented by numbers and digitized on a data base (Epi Info, version 5.01b) and analyzed. Out of the 89 farmers interviewed, 37.5% deworm their herd after clinical signs and 62.5% preventively. Generally, anthelmintics are applied from one to 12 times a year (average of 3.79 times a year) in all age categories of animals. Of the anthelmintics used in the last deworming, imidazothiazole was used exclusively by 17.1% of the farmers, benzimidazole by 9.8% and avermectin by 18.3%, while 55.8% used more than one anthelmintic class to deworm their animals. To choose the dosage, most farmers consult the product label (94.8%) and determine the volume to be applied, based on an estimate of the average body weight of each animal (62.9%). Improvements in the general appearance of the herd and weight gains of growing animals were observed by most farmers after deworming (87.3%). However, most of them (66.2%) recalled interrupting the use of some compound in the last few years, due to the detection of no improvement following treatment (32.7%), rising costs of the medication (28.6%), adverse reaction (8.2%), product not available at the time of purchase (4.1%) and decision to change the compound in use (10.2%). Most farmers (95.3%) intend to continue using the same control measures in the following year. Veterinarians play an important role in the farmer's choice to deworm their animals, as many seek advice from them. Therefore, programs aimed at technology transfer should include continuous updates on the subject, especially for veterinarians.

Reduction of Haemonchus contortus infective larvae by Harposporium anguillulae in sheep faecal cultures.

Harposporium anguillulae is a common nematophagous fungus which colonizes cattle pats deposited in Brachiaria decumbens pasture in Brazil. To assess its possible effect on free living stages of trichostrongylid nematodes, the reduction of Haemonchus contortus infective stages in sheep faecal culture was evaluated in vitro. Addition of 300,000 conidia per gram of faeces caused a reduction of 99.5% compared to the control group. This result indicates that H. anguillulae could be a candidate for the development of strategies for the biological control of trichostrongylid nematodes.

Efeito da aplicaçäo de conídios de Drechmeria coniospora em cultivos de fezes contendo ovos de Haemonchus contortus / Effect on an endorapasitic fungus, Drechmeria coniospora, in fecal cultures containing eggs of Haemonchus contortus

O efeito da adiçäo de conídios de Drechmeria coniospora, na reduçäo do número de larvas infectantes de Haemonchus contortus foi observado em um teste onde concentraçöes crescentes de conídios foram adicionadas às fezes de ovinos contendo 750 ovos do nematódeo em cada grama de fezes. Para o teste, pesaram-se individualmente 40 amostras de 4g de fezes. Dez amostras foram deixadas sem tratamento (controle), dez foram tratadas com 10 elevado à quinta, dez com 10 elevado à sexta e dez com 10 elevada à oitava potência conídios por grama de fezes. Em seguida, as fezes foram incubadas à temperatura ambiente durante sete dias. Após este período, as larvas foram extraídas, fixadas e posteriormente quantificadas. A concentraçäo de 10 elevado à oitava potência conídios por grama de fezes reduziu significativamente o número de larvas extraídas dos cultivos

Eficácia do cloridrato de levamisol em infestaçöes por nematódeos gastrintestinais em caprinos / Efficacy of levamisole against goat gastrointestinal nematodes

A eficiência do cloridrato de levamisol (LVZ) em formulaçäo oral foi testada em 35 caprinos divididos em cinco grupos de sete animais cada, infectados artificialmente com 5000 larvas oriundas de caprinos, onde havia predominância do Haemonchus contortus. Quatorze ovinos deslanados foram infestados na mesma ocasiäo com a mesma quantidade de larvas oriundas da mesma cepa. O número total de nematódeos e H. contortus dos grupos tratados foi menor que o dos näo tratados (P<0,05). A eficiência do LVZ na eliminaçäo da populaçäo de nematódeos estabelecidos nos caprinos foi de 84,5 por cento com a dose de 7,5 mg/kg de peso vivo (grupo 1), 93,6 por cento com a dose de 10 mg/kg (grupo 2) e 96,7 por cento com as doses de 12,5 e 15,0 mg/kg (grupos 3 e 4, respectivamente). Nos ovinos a reduçäo da populaçäo total de nematódeos estabelecidos foi de 86,0 por cento quando empregou-se 5 mg/kg de peso vivo. A eficiência do LVZ na eliminaçäo de H. contortus em caprinos variou entre 84,5 por cento e 100 por cento. Em ovinos a eficiência do LVZ na eliminaçäo do H. contortus foi de 87,5 por cento. Nenhuma diferença foi observada no número médio de Trichostrongylus spp (T. axei e T. colubriformis), Strongyloides papillosus e Oesophagostomum columbianum estabelecidos em caprinos e ovinos tratados e näo tratados (P<0,05). O LVZ em doses iguais ou superiores a 7,5 mg/kg de peso vivo é eficiente na eliminaçäo de nematódeos gastrintestinais de caprinos em regiöes onde o H. contortus seja predominante. As espécies Trichostrongylus spp, S. papillosus e O. columbiarum foram resistentes ao LVZ

Efectiveness of albendazole, oxfendazole and ivermectin against gastrointestinal nematode infection in goats

Vinte e sete caprinos sem raça definida infectados com nematódeos gastrintestinais foram distribuídos ao acaso em três grupos contendo sete caprinos em cada um e um grupo contendo seis caprinos. Os grupos de sete caprinos foram tratados com albendazole (5,7 mg/kg de peso vivo), oxfendazole (4,5 mg/kg de peso vivo) ou ivermectin (0,2 mg/kg de peso vivo) e o grupo de seis caprinos permaneceu sem tratamento. Sete dias após o tratamento os caprinos foram sacrificados para colheita, contagem e identificaçäo dos nematódeos. O número total dos nematódeos encontrados nos animais tratados foi menor do que nos näo tratados (P<0,05). Nenhuma diferença foi observada no número total de nematódeos encontrados entre os grupos tratados (P>0,05). A eficácia média dos grupos tratados foi de 85,8 por cento para o total de nematódeos encontrados e 87,8 por cento para Haemonchus contortus. Os dados enfatizam a necessidade de testes para determinaçäo da dose terapêutica adequada para caprinos

Efficacy of three broad-spectrum anthelmintics against gastrointestinal nematode infections of goats.

Groups of 10 goats, harbouring both naturally acquired and experimental infections of gastrointestinal nematodes, were drenched with either levamisole (5 mg kg-1), albendazole (3.8 mg kg-1) or parbendazole (15 mg kg-1), or remained untreated. Haemonchus contortus was the numerically dominant infection, with Strongyloides papillosus, Trichostrongylus colubriformis and Oesophagostomum columbianum also present. At 5-6 days post-treatment, goats were killed and necropsied. Post-mortem worm counts showed that the reduction in mean total worm burdens was 57.4% in levamisole-treated animals, 71.1% in the albendazole group and 85.1% in the parbendazole group. Reductions for H. contortus were 80.2, 87.9 and 83.9% in the levamisole-, albendazole- and parbendazole-treated groups, respectively. These data indicate that the anthelmintics in question are not being applied at an adequate dose rate for goats, and/or resistance to anthelmintics is occurring in the field in Pernambuco State, northeast Brazil.

Evaluation of lasalocid and decoquinate against coccidiosis resulting from natural exposure in weaned dairy calves.

Eighteen female Holstein calves, raised as natural herd additions under conditions typical of a well-managed midwestern United States dairy farm, were used in a natural-exposure study to determine the anticoccidial efficacies of lasalocid and decoquinate. Calves were allotted to 6 treatment blocks of 3 calves each as they were weaned. Within each block, calves were randomly assigned to be given either lasalocid or decoquinate or to remain as a nonmedicated control. Calves were given medication for 90 days and remained separated from other calves for 120 days. Adjusted weight gains were consistently greater in calves that were given medication; however, differences were not statistically significant. Fecal specimens were obtained from calves at weekly intervals during the study. Overall, oocyst shedding was low. During the medication period, quantitative mean fecal shedding of oocysts was reduced eightfold in calves given decoquinate and four-fold in calves given lasalocid, as compared with nonmedicated control calves. During the period following the medication period, calves that had been controls shed fewer oocysts than did calves that had previously been given medication. A pairwise comparison of the proportion of specimens that were oocyst-positive was made to assess qualitative oocyst shedding among treatment groups. During the medication period, qualitative oocyst shedding (all species, Eimeria bovis, E zuernii, species other than E bovis and E zuernii) was greater in controls than in either lasalocid-or decoquinate-treated groups. Like-wise, lasalocid-medicated calves shed oocysts more frequently than did the decoquinate-medicated group. After medication, qualitative findings were reversed. Little diarrhea was noticed in treatment or control calves during the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Seasonal prevalence of gastrointestinal nematodes of goats in Pernambuco State, Brazil.

During each of 36 1-month periods from April 1979 to March 1982, 3-4 goats selected from typical farms were necropsied and examined for gastrointestinal nematodes. The goats were male, 12 months old, born on the farm and raised without any anthelmintic application. At the beginning of each month, from April 1981 to March 1982, three 12-month-old male goats shown to be free of gastrointestinal nematodes after anthelmintic treatment were grazed with a flock of naturally infected goats (tracer goats). At the end of each month, these goats were placed on a cement-floored pen and were maintained there for 4 weeks prior to necropsy and examination for gastrointestinal nematodes. Every goat examined was found to be parasitized by more than one species of nematode. Haemonchus contortus, Strongyloides papillosus and Oesophagostomum columbianum were the most prevalent nematodes found. Total worm burdens present in the farm animals were highest during late rainy/early dry season (March-June) and lowest in mid-rainy season (January-February). The acquisition of nematodes by tracer goats occurred mainly from mid-rainy to early dry season (January-June).

Seasonal prevalence of gastrointestinal nematodes of beef calves grazed on irrigated pastures in the lower Sacramento Valley of California.

Two worm-free calves were allowed to graze on irrigated pasture with a naturally infected herd for each of 34 one-month periods from November 1979 to August 1982. After each grazing period, the calves were transferred to a cement-floored pen for 3 weeks and then were euthanatized and necropsied. Ostertagia ostertagi and Cooperia oncophora were the most prevalent species of nematodes recovered. Adults and larvae of Ostertagia spp and Cooperia spp were most numerous in winter and spring and least numerous during summer. The proportions of Ostertagia spp that were inhibited as fourth-stage larvae increased in late fall, peaked from March through April, and then decreased to low values during summer. The maximal inhibition in 1980, 1981, and 1982 was 72, 65, and 62%, respectively. The number of larval Cooperia spp was highest in winter months and, except for one grazing period when 55% of the Cooperia spp were larvae, the total numbers represented less than 15% of the nematode population during all grazing periods. Other nematodes encountered were Trichostrongylus axei, Haemonchus spp, O lyrata, and O occidentalis in the abomasum; C surnabata, C punctata, Nematodirus helvetianus, T colubriformis, and Bunostomum phlebotomum in the small intestine; and Oesophagostomum venulosum and Trichuris ovis in the large intestine.