Recent and episodic volcanic and glacial activity on Mars revealed by the High Resolution Stereo Camera.

The large-area coverage at a resolution of 10-20 metres per pixel in colour and three dimensions with the High Resolution Stereo Camera Experiment on the European Space Agency Mars Express Mission has made it possible to study the time-stratigraphic relationships of volcanic and glacial structures in unprecedented detail and give insight into the geological evolution of Mars. Here we show that calderas on five major volcanoes on Mars have undergone repeated activation and resurfacing during the last 20 per cent of martian history, with phases of activity as young as two million years, suggesting that the volcanoes are potentially still active today. Glacial deposits at the base of the Olympus Mons escarpment show evidence for repeated phases of activity as recently as about four million years ago. Morphological evidence is found that snow and ice deposition on the Olympus construct at elevations of more than 7,000 metres led to episodes of glacial activity at this height. Even now, water ice protected by an insulating layer of dust may be present at high altitudes on Olympus Mons.

Circulating immonoglobulin M: increased concentrations in endemic and sporadic goiter.

Increased concentrations of immunoglobulin M have been found in the circulation of approximately half of patients with either endemic or sporadic nontoxic goiter. Blood was obtained from patients in several iodine-deficient goitrous areas; the patients with sporadic goiter resided in or about New York City. Concentrations of immunoglobulins G, A, and D were normal. Blood for control purposes was taken from patients residing in cities near the goiter areas where there was no iodine deficiency, and in New York City. Most of these samples came from hospitalized patients without known thyroid disease and were collected at random. Chi-square values for the difference between the number of goitrous patients with elevated concentrations of immunoglobulin M and those in the control patients were highly significant statistically.

Total and free triiodothyronine in human serum.

A reliable method has been developed for the determination of total serum T3, dialyzable fraction (DFT3), and absolute concentration of free T3 (AFT3). Total T3 values (mean +/- SD) were: healthy euthyroid subjects, 0.33 +/- 0.07 mug per 100 ml; hyperthyroid patients, 0.71 +/- 0.1 mug per 100 ml; hypothyroid, 0.10 +/- 0.03 mug per 100 ml. Values (mean +/- SD) for DFT3 in these groups were 0.46 +/- 0.14%, 0.78 +/- 0.17%, and 0.16 +/- 0.08%, respectively. Calculated values for AFT3 were: 1.51 +/- 0.4 mmug per 100 ml, 5.00 +/- 0.6 mmug per 100 ml and 0.24 +/- 0.1 mmug per 100 ml, respectively. Dilution of serum before dialysis lowered estimated DFT3 values. Enrichment of serum with labeled T3 in the range examined did not affect DFT3. However, DFT3 was increased by addition of Merthiolate to serum in concentration 1: 10,000 due to displacement of T3 from thyroxine-binding globulin to albumin. The data suggest that triiodothyronine may play a considerably more important role in normal and pathological physiology, as evidenced by kinetic analysis using these data. A metabolic role for T3 equal to that of T4 is indicated.

Materials indistinguishable from iodotyrosines in normal human serum and human serum albumin.

Materials indistinguishable from authentic mono- and diiodotyrosines were identified in extracts of normal human serum as well as in extracts of purified human serum albumin. These materials were not found in association with the other serum proteins. Identification of MIT and DIT was made by a technique using rechromatography to constant specific activity, as well as by the Barker wet ash distillation method, which established the compounds in question as being iodinated ones. By two different extraction and chromatographic methods we estimated the amounts of both MIT and DIT present in normal human serum or albumin; the estimates were in good agreement. These compounds together constituted between 19% and 25% of the extractable serum iodine.

Graves' disease following acute (subacute) thyroiditis.

The development of Graves' disease with positive thyroid-stimulating antibody titers is described in a woman, five months after onset of the putatively viral disorder, acute (subacute) thyroiditis. There was no evidence of transient hyperthyroidism during the acute episode. The arguments for and against a causal relationship between the two diseases have been reviewed. The present experience adds to the earlier suggestion that the association may represent cause and effect.

Similar serum IgM concentrations in Greek endemic goiter and control populations: failure to confirm previous experience.

Circulating immunoglobulin M (IgM) concentrations were determined in 47 nontoxic goiter patients from four Greek endemic goiter areas, and in 13 patients from Athens, a non-goitrous area; and compared with 38 control non-goitrous subjects from the same goiter regions, and 23 more controls from Athens. The values in both goitrous and non-goitrous groups were indistinguishable. Current techniques for single radial immunodiffusion were employed. The results are expressed in standardized international units/ml serum, instead of the formerly used mg/dl. The present findings are in disagreement with the earlier observation from this laboratory that 40 per cent of goitrous patients had elevated IgM values compared with 10 per cent of control subjects.

Utility of thyroid aspiration biopsy.

The utility of fine-needle aspiration biopsy to detect carcinoma in thyroid nodules was evaluated by a decision-analysis approach in 102 patients. The procedure caused no morbidity. Cytologic diagnoses were categorized as unsatisfactory (4), no abnormality detected (61), atypical (13), suspicious for malignancy (14), malignancy (2), and inflammation (8). The duration of follow-up averaged 13 months. Of 21 thyroidectomy patients, 10 (48%) had carcinoma. Half of the ten patients operated upon for suspicious cytologic findings were found to have malignancy. Assuming criterion I, that atypical, suspicious, or malignancy results indicated cancer, sensitivity was 90%, specificity 77%, false positive fraction 23%, positive predictive value 31%, negative predictive value 99%, and accuracy 79%. Assuming criterion II, that only suspicious or malignancy cytologic findings represented carcinoma, sensitivity was 70%, specificity 90%, false positive fraction 10%, positive predictive value 44%, negative predictive value 96%, and accuracy 88%. We conclude that sensitivity and specificity of fine-needle aspiration biopsy vary depending upon the use of criterion I or II. Accuracy is highest if atypical results are not considered to represent carcinoma. Positive predictive values remain low and negative predictive values are high in either case. The utility of fine-needle aspiration biopsy when interpreted in relation to clinical criteria is supported by these results.

Modification of the classification of the eye changes of Graves' disease.

The original (1969) classification of the Eye Changes of Graves' Disease has been retained except for Classes 1 and 3. Class 1 has been limited so that proptosis of 23 mm or greater is placed in Class 3, even if the patient is asymptomatic. Grading of Classes 1 and 2 has been left to the individual physician or clinic, but we urge that the suggested criteria for grading Classes 3 through 6 be used. Progression of disease is not necessarily sequential through each of the classes, and ethnic factors and myopia may influence the extent of proptosis in normal subjects.