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Biomedical subjects

S Packer

Publications and source records attributed to S Packer.

52 records · Page 3Linked to original sources
PubMed1976

Immunological phenomena in the jejunum and serum after reintroduction of dietary gluten in children with treated coeliac disease.

Jejunal mucosal immunoglobulin-containing cells of all three major classes (IgA, IgM, IgG) were increased in coeliac children on gluten-containing diets but only IgM cell numbers were raised in those on gluten-free diets. Patients with subtotal villous atrophy had greater numbers of immunoglobulin-containing cells than patients with normal mucosa. In previously treated patients studied before and after three months on a gluten-containing diet ther was an increase in all three classes of cell, IgM containing cells showing the greatest proportional rise. Basement membrane staining with anti-IgA serum occurred in coeliacs and was most intense in untreated patients. Apart from one patient with very low levels of serum IgA, serum immunoglobulins did not differ from normal. However, after reintroduction of gluten to the diet a significant fall in serum IgM concentrations occurred compared with levels in the same patients while on gluten-free diets. It seems probable that both IgA and IgM systems are important in the immunopathogenesis of the small intestinal lesion of childhood coeliac disease.

Adolescent↗
PubMed1975

Quinoline analog labeled with iodine 123 in melanoma detection.

Using the Greene melanoma in the hamster (Syrian Golden), the radiopharmaceutical, 123-1-4(3-dimethylaminopropylamino)-7-Iodoquinoline, was tested for its ability to localize melanoma. This quinoline analog has been described for use in the detection of melanoma, but this is the first report, to our knowledge, of its being used with an 123-l label. Hamsters with either skin or eye melanomas were studied. Both melanomas could be seen with a gamma camera at three hours after injection. In vitro analysis confirmed the tumor specificity. Thus, it appears that this preclinical trial of a new radiopharmaceutical justifies clinical testing to determine its value in the localization of melanomas of the eyes and skin of humans.

Administration, Oral↗
PubMed1975

Limitations of xylose tolerance test as a screening procedure in childhood coeliac disease.

The usefulness of the xylose tolerance test as a screening procedure for coeliac disease has been reassessed in 54 children with suspected coeliac disease. 5- and 24-hour urinary excretion rates of xylose were of no value in discriminating between patients with and without coeliac disease; similarly, the 3-hour blood xylose concentration was nondiscriminatory. Three (15-8%) patients with subtotal villous atrophy and 8 (61-5%) with partial villous atrophy due to coeliac disease had one-hour blood xylose values which fell within the normal range. The effect of withdrawal or reintroduction of dietary gluten on sequential one-hour blood xylose levels was variable and generally unhelpful in predicting those patients who developed gluten-induced mucosal changes. The results of the present study emphasize the serious limitations of the xylose tolerance test as a screening procedure in childhood coeliac disease. It is recommended that the use of the urinary xylose test should be abandoned in the paediatric population. A normal one-hour blood xylose value does not exclude a diagnosis of coeliac disease even in young children who have never received a gluten-free diet. A clinical suspicion of coeliac disease remains the most important single factor in deciding whether to preform a jejunal biopsy.

Adolescent↗
PubMed1975

Localization of radioactive lead in ocular and skin melanoma.

The ability of radioactive lead to localize melanomas was studied. The Greene melanoma in the Syrian Golden hamster served as a model for both skin and ocular melanoma. The affinity of heavy metals for neoplasms has been studied but previous reports have been inconsistent as to tumor specificity. For this investigation the radioactive lead (203-Pb,) was studied as the chemical complex 203-Pb-Tris. Significant tumor:nontumor ratios were found in ocular melanoma and the concentration in the lens was minimal. The ratio of per cent uptake per gram of tumor: per cent uptake per gram in control tissue with skin melanoma was 9.4 at 24 hours and for the eye melanoma the ratio was 26.3 at 24 hours. The affinity of 203-Pb-Tris for melanomas appears to be as promising as other compounds presently being evaluated for ocular scintigraphy, namely, labeled quinoline analogs. Therefore, further preclinical evaluation is warranted.

Animals↗
PubMedDate not supplied

Monte Carlo dosimetry for 125I and 60Co in eye plaque therapy.

Monte Carlo calculations of radiation dosimetry using MORSE code are performed for 125I and 60Co point sources in a cylindrical head phantom that simulates the geometry of eye plaque therapy for choroidal melanoma. We obtain the dose variation in the eye at submillimeter intervals over distances as close as 1 mm and up to 2.5 cm from the source. The calculations for 125I are performed for the phantom media of water, protein, and a homogenized protein-water mixture simulating the composition of the eye. Relative dose functions for 125I for these phantom media are fitted to second-degree polynomials. Agreement is found with published results. The relative dose function for 60Co at eye position in the water head phantom is fitted to a third-degree polynomial and compared with that for 60Co at the center of a large water sphere. A boundary effect due to the head phantom-air interface on the dose distribution for 60Co is demonstrated. The dose falloff with distance is faster for the eye geometry compared with the bulk geometry. We also show that the relative dose distributions within the tumor are comparable for 125I and 60Co by comparing their relative dose functions. This result is consistent with the success of clinical trials of large melanoma treatments with 125I plaques.

Biophysical Phenomena↗