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Biomedical subjects

M Okerlund

Publications and source records attributed to M Okerlund.

7 recordsLinked to original sources

Failure to inhibit irrelevant information in non-clinical schizotypal individuals.

The present study compared negative priming performance in a non-clinical sample of individuals based on their schizotypal personality scale (STA) scores. There were 13 High STA and 19 Low STA individuals. High, but not Low, STA individuals displayed deficient negative priming, replicating previous findings. Converging evidence for this claim was observed in the correlation between negative priming and STA score, r = -.64, p < .01, supporting the notion that individuals with high STA scores exhibit an inability to adequately inhibit irrelevant information. Both groups did not differ on a simple reaction time control task, ruling out the possibility that observed negative priming differences across groups were the result of a simple motor reaction time difference.

Adult↗

Implicit memory of nonclinical schizotypal individuals.

In the present study a form of implicit memory performance was examined by employing the serial reaction-time paradigm with a nonclinical sample of 22 hypothetically schizotypal college students and 22 nonschizotypal college students. The formation of new associations was tested; analysis showed no difference between these two groups on this measure of implicit memory.

Adult↗

Localizing studies in patients with persistent or recurrent hyperparathyroidism.

Preoperative localizing studies are essential for patients with persistent or recurrent hyperparathyroidism requiring reoperation, because of loss of normal tissue planes and because the hyperfunctioning parathyroid tissue that remains is more likely to be situated in an ectopic position. The value of noninvasive and invasive localizing techniques was evaluated in 59 consecutive patients undergoing reoperation for persistent (40 patients) or recurrent (19 patients) hyperparathyroidism. Magnetic resonance imaging was performed in 17 patients; 11 results (65%) were positive, 3 (18%) were negative, and 3 (18%) were false-positive. Ultrasonography was performed in 52 patients; 29 (56%) were positive, 16 (31%) were negative, and 7 (13%) were false-positive. Computed tomography was performed on 41 patients; 19 (46%) were positive, 16 (39%) were negative, and 6 (15%) were false-positive. Thallium chloride 201-technetium 99m pertechnetate scans were used in 39 patients; 19 (49%) were positive, 11 (28%) were negative, and 9 (13%) were false-positive. One or more of these noninvasive tests was positive in 78% of the cases. Highly selective venous catheterization with measurement of immunoreactive parathyroid hormone concentration localized the abnormal parathyroid gland in 20 of 28 patients (71%) overall and in 8 of the 14 patients (57%) whose tumors were not identified by the noninvasive techniques. Since false-positive results were common, a combination of localizing studies was helpful in identifying the abnormal gland. Fifty-three of the 59 patients (90%) were successfully treated at the initial reoperation and three were successfully treated at a second reoperation. Advances in parathyroid localization have contributed to the improved surgical results in patients with persistent or recurrent hyperparathyroidism.

Adult↗

Prolonged brain retention of contrast agent in neonatal herpes simplex encephalitis.

A neonate with herpes simplex encephalitis type 2 manifested progressively increasing density of the gray matter on serial computed tomographic scans. Postmortem examination of the brain proved the cause of the increased density to be a high concentration of iodine that had been retained following the intravenous administration of sodium diatrizoate 25 and 16 days previously. This demonstrates that a water-soluble iodinated contrast agent or its iodine component may be retained in the brain for a prolonged period of time. It is recommended that such agents be avoided when possible in neonates with herpes simplex encephalitis.

Brain↗

Feasibility of localizing ectopic testes by 131I-labeled luteinizing hormone scintigraphy.

A new method for localizing ectopic testes preoperatively was investigated in rats. Twenty hours after administration of iodine-131 luteinizing hormone the position of normal descended testes was easily identified by scintigraphy. Clinically, this technique may offer a noninvasive and practical means of locating testes undetected by palpation. The complexity and hazards of the surgical intervention to follow would thus be greatly reduced.

Animals↗

Low cost intrathyroidal iodine quantification with a fluorescent scanner.

A thyroid fluorescent scanner has proven to be useful for imaging thyroids in cases where isotope scans are contraindicated. Minor modifications of a commercially available scanner make possible total intrathyroidal quantification, which aids in the differentiation between primary and secondary hypothyroidism and in the diagnosis of thyroiditis.

Costs and Cost Analysis↗

Imaging characteristics of a small germanium camera.

A high purity germanium gamma-camera has been developed and is currently being evaluated. This camera incorporates unique performance parameters such as a 2 mm full-width spatial response function with rejection of multiple-scatter in the detector, a 2.2% FWHM energy resolution for 99 mTc, a 180 nsec paralyzable dead-time, and a 2 mu sec non-paralyzable dead-time. Imaging studies demonstrate the superior capabilities of this instrument.

Animals↗