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Biomedical subjects

J M Paul

Publications and source records attributed to J M Paul.

6 recordsLinked to original sources
PubMed1989

Characteristics of clometacin-induced hepatitis with special reference to the presence of anti-actin cable antibodies.

The clinical, biochemical, histopathological and immunological features of 30 cases of clometacin-induced hepatitis are described. The age range of the patients was 32-84 years with a notable female predominance of 29:1. The hepatitis was highly cytolytic with high values of transaminases but with little or no cholestasis. Gammaglobulins were higher than 18 g/l in 73% of the cases. 25 liver biopsies were performed and showed acute hepatitis with a predominant centrilobular necrosis in 17; chronic aggressive hepatitis was noted in 8 cases but 1 showed concomitant cirrhotic changes. Anti-tissue antibodies were looked for in all cases. Anti-smooth muscle antibodies of anti-actin cable type (titre 1/80 to 1/2, 560) were detected in 19 cases, anti-nucleus antibodies in 16 cases which were associated to the former in 14 cases. The above findings show that clometacin produces a hepatitis syndrome quite akin to autoimmune chronic active hepatitis (lupoid hepatitis) and to the hepatopathy induced by oxyphenisatin.

Actins↗
PubMed1988

Uniform analysis of dose distribution in interstitial brachytherapy dosimetry systems.

In brachytherapy, articles are published with dose and homogeneity specifications using different systems which are hard to compare. For the same "stated dose", the dose delivered, volume treated and activity chosen are not the same in different systems, due to the fact that the source placement rules are different. In this article, the authors have circumvented this problem by the use of an approach not applied hitherto, viz. by determining the value of the Uniformity index (UI) of an implant using different systems. This value takes into account the integral dose within the treatment volume and is compared with an idealized implant, where the dose is uniform and the target and treatment volumes are the same. This method of evaluation has been applied for single plane, multiple plane and cylindrical volume implants using the Manchester, Quimby and Paris systems. Although the results obtained are different, the degree of closeness of these values are striking, with some minor exceptions. Thus, it is possible to combine all the brachytherapy parameters, such as: dose, homogeneity, treatment volume within a single value to determine the quality of an implant.

Brachytherapy↗
PubMed1975

Dosimetric reliability of thermoluminescent phosphors (TLD-too).

The dosimetric reliability of TLD-100 has been studied in view of the fact that these TLDs are extensively used for patient dosimetry in the case of irregular fields and where patient's contour creates special problems. TLDs have also been used in intercavitary dosimetry (e.g. esophagus and rectum) and in some cases of dosimetric comparison of radiation output. However, it appears that these TLDs are unsuitable for most practical dosimetry due to poor reproducibility and system error. It is found that the same TLD-chip gives widely divergent readings for the same exposure even when correction for the system error is made. The composite uncertainty under the best experimental conditions is about +/-3.5%.

Humans↗
PubMedDate not supplied

Comparison between continuous and discrete sources in the Paris system of implants.

Since the Paris system of interstitial brachytherapy is based on iridium wires, the consequences resulting from the substitution of discrete point sources in afterloading ribbons have been analyzed. The results are presented in this article for single ribbons, single plane implants of thicknesses 0.5 and 1.0 cm, and biplanar implants of both equal and unequal areas of sizes most frequently used clinically in the thickness range 1.5-3.0 cm. These results indicate changes in the quality of implants using wires and point sources up to the maximum spacing of 1.5 cm. The quality of the implants is judged on the basis of a parameter, the uniformity index, which takes into account both the size of the treatment volume for a given target volume and the homogeneity within the treatment volume as determined from the integral dose. Other implant parameters such as total activity, treatment volume, total volume receiving greater than twice the stated dose rate, average dose rate, and variation of basal dose rate, etc., are also provided to indicate quality of the implants. The results with the customary seed spacing of 1 cm are compatible with those using wires and are found to have improved quality in many cases.

Brachytherapy↗