The role of ear mites of the genus Raillietia (Acari: Raillietiidae) in otitis of domestic ruminants / O papel dos ácaros do gênero Raillietia (Acari: Raillietiidae) na otite de ruminantes domésticos

This paper presents a hypothesis on the involvement of species of the genus Raillietia Trouessart in the pathology of parasitic otitis in domestic ruminants. The chelicerae and claws of the tarsi are structures that contribute significantly towards producing primary lesions. The movable digits of the chelicerae accidentally injure the epithelium that lines the ear canal, while the claws of the tarsi perforate the epithelium, allowing the mites to affix themselves while feeding. The lesions in the epithelium caused by the chelicerae and the claws favor multiplication of the bacteria that inhabit the ear canal, resulting in typical cases of otitis.

Neste trabalho apresentamos uma hipótese para explicar o envolvimento dos ácaros do gênero Raillietia na patogênese da otite parasitária em ruminantes domésticos. As quelíceras e unhas dos tarsos são estruturas que contribuem significativamente para produzir as lesões primárias no epitélio. Os dígitos móveis das quelíceras acidentalmente causam injúria no epitélio que reveste o canal auditivo, enquanto as unhas dos tarsos perfuram o epitélio para permitir a fixação dos ácaros durante sua alimentação. As lesões no epitélio causadas pelas quelíceras e unhas dos tarsos favorecem a multiplicação das bactérias que habitam o canal auditivo, resultando em casos típicos de otite.

[Absorbed dose measurement of photon beam with Farmer-type ionization chambers in Japanese dosimetry protocols].

The Japan Society of Medical Physics (JSMP) has published a new dosimetry protocol "JSMP-01" (standard dosimetry of absorbed dose in external beam radiotherapy) which conforms to the recommendations of the International Atomic Energy Agency (IAEA TRS-398) and the American Association of Physicists in Medicine (AAPM TG-51) protocols for the calibration of radiotherapy beams. Since the new protocol offers the physical data for the Famer-type ionization chambers of the various wall materials, the user can measure the absorbed dose at reference point (D(r)) using most of the commercially available Famer-type ionization chambers. In this paper, the six Famer-type ionization chambers of the various wall materials are examined for photon beam by two ways. To verify the JSMP-01 protocol as the first way, D(r) was cross-measured based on the JSMP-01 protocol using a Farmer-type ionization chamber of the acrylic wall material which is called "JARP-chamber" and the Farmer-type ionization chambers of the various wall materials, and compared. To compare the basic data in previous and new protocols as the second way, D(r) was measured based on the previous protocol (JSMP-86) and the JSMP-01 protocol using the Farmer-type ionization chambers of the various wall materials. Dose calculation was made using common exposure calibration factor for (60)Co gamma-rays (Nc) for each of the Farmer-type ionization chambers. Measurement was made with each ionization chamber for 6 and 10 MV photon beams in two facilities. D(r) were found to agree to that of JARP-chamber within about +/- 1% despite significant differences of ratio of calibration factor (k(D,X)) and beam quality conversion factor (k(Q)) for photon beams. The ratios JSMP-01/JSMP-86 of the reference dose were found to lie on between 0.999 and 1.004 for 6 MV and on between 0.999 and 1.005 for 10 MV depending upon the Farmer-type ionization chambers used. The largest discrepancies between the previous and new protocols arise from the use of different data of k(D,x) x k(Q) and C(lambda) for the absorbed dose conversion factors of each ionization chamber.

Contribution of Cerenkov radiation in high-energy x-ray and electron beam film dosimetry using water-substitute phantoms.

The contribution of Cerenkov radiation in high-energy film dosimetry was investigated using commercially available water-substitute phantoms. Doses were evaluated using six phantoms: RMI-451, Mix-DP, WE-211, WE-Black, PMMA and PMMA-Black. The contribution of Cerenkov radiation was determined from the shielded and unshielded evaluation doses when a bare film was inserted into the phantom in a dark room and irradiated. For both x-ray and electron beams, Cerenkov radiation produced a phantom-dependent increase in the unshielded dose when compared with the shielded dose. We also found that the darker the phantom, the smaller the contribution of Cerenkov radiation. These results suggest that for film dosimetry using bare film, the accuracy of dose evaluation may be improved by using phantoms with high opacity.

[Wiener spectrum and relative electron density resolution in heavy ion CT based on measurement of residual range distribution].

The relative electron density resolution was discussed by the Wiener spectrum in the heavy ion CT image. The two-dimensional (2D) Wiener spectrum in the CT image was obtained from the one-dimensional (1D) Wiener spectrum of the measured residual range distribution of the water phantom for a single projection angle, and the relative electron density resolution in the CT image was calculated from the 2D Wiener spectrum. To examine the usefulness of this method, the relative electron density resolution was also estimated by other two methods; the calculation using the Wiener spectrum of the reconstructed image of the water phantom, and the estimation by the reconstructed image of the electron density resolution phantom. The result of the first method was similar to those of the other two methods. Therefore, it is useful to estimate the relative electron density resolution by the 1D Wiener spectrum of the measured residual range distribution of the water phantom for a single projection angle.

[Trial production of water substitute phantom considering the effect of light].

We have produced a novel water substitute phantom suitable for film dosimetry, while retaining the radiological property of a conventional water substitute phantom. The novel phantom excludes the effect of light, which is known to affect the accuracy of results on conventional phantoms. The effect of light was eliminated by appropriately adjusting the quantum of the carbon black to that of a conventional phantom material. Through comparison of the novel phantom with a conventional phantom it was shown that the absorbed dose determined by conventional phantom was 15% higher for 10 MV X-rays and 18% higher for an 18 MeV electron beam, attributable to the contamination of Cerenkov light. Although the net optical density of the film increased with time owing to the optical permeability of the phantom, that of the novel phantom did not vary with time. The novel phantom was therefore shown to be unaffected by such local light and by the optical transmission of the phantom.

Heavy ion CT system based on measurement of residual range distribution.

The heavy ion CT system is proposed which is based on measurement of the residual range distribution by a fluoroscopy detector consisting of an intensifying screen and a CCD video camera. To investigate the fundamental performance of the proposed system, the spatial and density resolutions of the CT image were evaluated. The heavy ion beam 12C accelerated up to 400 MeV/u by HIMAC was used in this study. A series of projection images of two types of phantoms (PMMA pipes with several sizes and various kinds of rods with different electron densities) were experimentally taken for five values of range shifter thickness at each projection angle. From these images, the residual range distribution was obtained and used to reconstruct CT images of the relative stopping power which were obtained by the filtered back projection method with the Shepp-Logan filter after noise reduction processing by the median filter. As a result, the spatial resolution was found to be less than 2 mm and the relative density resolution around the density of water was less than 0.07.

Influência do Ponto de acupuntura BP-10 (Xuehai) sobre a hemostasia no cäo (Canis familiaris) / Influence of acupoint Sp-10 (Xuehai) on the hemostasis in dogs (Canis familiaris)

Encontra-se na literatura, em textos empíricos, a informaçäo de que a acupuntura pode ser utilizada para o controle da hemorragia. O presente estudo foi designado para investigar o efeito da acupuntura no processo hemostático em cäes (Canis familiaris), utilizando o ponto de acupuntura BP-10 (Xuehai). Material e método - Foram utilizados dez cäes sem raça definida, selecionados através de exame clínico minucioso e testes laboratoriais de rotina. O tratamento por acupuntura consistiu na inserçäo de agulhas filiformes (0,20 x 30mm) bilateralmente no BP-10 (Xuehai), sendo estimuladas manualmente a cada cinco minutos e mantidas durante 20 minutos. Para avaliaçäo da hemostasia foram utilizados os testes de tempo de protrombina (TP), tempo de tromboplastina parcial ativada (TTPA) e tempo de sangramento (TS), realizados antes da inserçäo da agulha de acupuntura, 20 minutos após e seis horas após o tratamento, servindo cada animal como seu próprio controle, uma vez que nenhuma variável interferiu nas três avaliaçöes, a näo ser o próprio tratamento em estudo. Resultados - Ainda que resultados estatisticamente significantes tenham sido verificados apenas em TTPA (que avalia o sistema intrínseco da coagulaçäo) nos tempos II e III em relaçäo ao tempo I (p < 0,01 no teste de Tukey), alteraçöes no mesmo sentido também foram observadas em TS e TP, permitindo supor influência do tratamento aplicado sobre a hemostasia primária e secundária.