James S. Robertson

The kidney in progressive systemic sclerosis: a prospective study.

Nine normotensive progressive systemic sclerosis patients with normal renal function underwent renal biopsy. Four specimens had prominent vascular abnormalities, two mild vascular abnormalities, and three were normal. Vascular deposits of C3 were present in all specimens. Plasma renin activity was elevated in three of four patients with prominent vascular abnormalities, one of two patients with mild vascular lesions, and none of two patients with normal biopsies. Plasma renin activity elevation in response to cold pressor testing in the four patients with prominent vascular lesions was 5.6 ng/ml.h compared to 0.55 ng/ml.h in those with mild or no lesions and 0.26 ng/ml.h in six control subjects. These data indicate that renal vascular lesions may be present in normotensive patients. Elevation or a substantial rise in plasma renin activity (1.8 ng/ml.h or greater) in response to cold pressor testing suggests preclinical renal involvement.

Radiation Dose in the Selection of 131I or Surgical Treatment for Toxic Thyroid Adenoma

Clinicians, by their patterns of referral to colleagues in nuclear medicine or surgery, may strongly influence the selection of 131I versus surgical treatment for patients with toxic thyroid adenoma. The information presented here is intended to aid them in making an informed choice. As nodule size of an adenoma increases from 2 cm to 6 cm, the amount of radioiodine administered to the patient to deliver the same dose (30 000 rads to the nodule center, assuming a 30% uptake) increases from 5.6 mCi to 135 mCi. Concurrently, the suppressed thyroid tissue receives a radiation dose as high as 2300 rads. Despite these potentially carcinogenic doses, few patients with radioiodine-induced thyroid tumors have been reported; we discuss possible reasons for this. For young patients with large nodules, surgery is preferred.

Comparison of Three Platelet Markers for Measurement of Platelet Survival Time in Healthy Volunteers

We studied mean platelet survival times in healthy volunteers with use of [51Cr]disodium chromate, 111In-oxine (in a solution of acid-citrate-dextrose [ACD] and saline), and 111In-tropolone (in ACD-plasma) as markers. Differences found between the 51Cr and 111In labels probably can be attributed to a variation in localization of the label on the cell and of renal handling of the free label after release. The mean platelet survival time with 51Cr was slightly longer than the survival time with both indium labels and showed a sex difference not seen with 111In-oxine. Protein-bound plasma 51Cr was lower than plasma 111In and remained constant throughout the study. Plasma 111In increased with time. For survival time calculations, no correction for free 51Cr is necessary, but correction should routinely be performed when 111In markers are used. Both 111In markers gave similar results with respect to platelet survival time. The somewhat more elaborate plasma labeling procedure with tropolone shows no measurable advantage over the original 111In-oxine method. 111In-tropolone labeling takes less time and maintains platelets in the physiologic environment of plasma during incubation. Biodistribution studies show no difference between the two 111In markers.