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Biomedical subjects

R Loo

Publications and source records attributed to R Loo.

17 recordsLinked to original sources

Resection of advanced stage neuroblastoma with the cavitron ultrasonic surgical aspirator.

Current protocols for the treatment of neuroblastoma emphasize total or near total resection of tumor to improve survival. This is preferentially performed as a primary procedure, or is attempted at a second-look operation. Unfortunately, this tumor often grows to large size with invasion of the spinal canal, or encasement of major vascular or other retroperitoneal structures. A primary attempt at complete removal may result in difficult-to-control hemorrhage or injury to, or loss of, vital organs. A second-look procedure carries other intrinsic risks. It often must be performed during a period of chemotherapeutically induced hematologic and immunologic suppression. The presence of adhesions and dense scar tissue increases the complexity of the dissection. The Cavitron Ultrasonic Surgical Aspirator (CUSA) combines continuous fragmentation, irrigation, and aspiration in one instrument. Tissues high in water content are selectively fragmented and aspirated, while tissues high in collagen and elastin (such as blood vessels and pseudocapsular walls) are selectively spared. Five patients, two with large pelvic dumbell tumors, two with large intrathoracic tumors, and one with a seemingly unresectable large right adrenal tumor (crossing the midline with extensive aortocaval nodal involvement) had total or near-total resection accomplished using the CUSA. In these patients, initial resection of the relatively soft inner part of the tumor left a collapsed pseudocapsule, which was then removed under greatly improved exposure in a relatively small field. The constant aspiration virtually eliminated tumor spillage. Since most vessels were skeletonized without penetration, total blood loss was minimized. There were no intraoperative or postoperative complications.

Adrenal Gland Neoplasms

Efficacy of bucindolol in systemic hypertension.

The hemodynamic effects of oral bucindolol, a non-selective beta-adrenergic blocking agent with intrinsic sympathomimetic activity and direct vasodilating properties, were studied at rest and during handgrip exercise with a flotation-directed pulmonary artery catheter in 12 patients with mild to moderate essential hypertension. After the initial dose of 150 mg of bucindolol, blood pressure (BP) was significantly reduced and cardiac output was increased (from 5.9 +/- 0.8 to 6.8 +/- 1.6 liters/min) in the supine position and during exercise (p less than 0.05). Systemic vascular resistance was reduced (from 1,555 +/- 339 to 1,311 +/- 467 dynes s cm-5, p less than 0.01) at rest and without significant changes during exercise. There were increases in heart rate (13 +/- 13%, p less than 0.01) and right atrial (69 +/- 77%, p less than 0.05), pulmonary arterial (38 +/- 24 %, p less than 0.001) and pulmonary artery wedge pressures (62 +/- 46%, p less than 0.001) during exercise. Bucindolol did not change these variables at rest or during exercise. Bucindolol increased plasma norepinephrine levels both at rest (from 330 +/- 151 to 588 +/- 320 ng/liter, p less than 0.01) and during exercise (from 468 +/- 220 to 685 +/- 390 ng/liter, p less than 0.05). After 4 weeks of bucindolol with doses of 50 to 200 mg 3 times daily, BP was reduced in both supine and standing positions (mean arterial BP of 11 +/- 7% [p less than 0.001] and 11 +/- 6% [p less than 0.001], respectively), without changes in cardiac output, systemic vascular resistance or plasma norepinephrine level.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists

Note on the relationship between trait anxiety and the Eysenck Personality Questionnaire.

Administered the State-Trait Anxiety Inventory A-Trait scale and the Eysenck Personality Questionnaire to 97 females and 105 males under neutral conditions. The interrelationships gave limited support to Eysenck's hypothesis that anxiety is a dimension oblique to extraversion and neuroticism such that high anxiety is associated with high introversion and neuroticism. Trait anxiety was independent of the psychoticism and lie dimensions.

Adolescent

The orthogonal rotation of factors in clinical research: a critical note.

Examined the current trends in rotation procedures used in factor analyses in clinical research. It was found that orthogonal rotations, usually varimax procedure, were overwhelmingly the rotational choice. It was suggested that in many analyses, investigators in this area of research may be imposing orthogonality on data that might better be interpreted as oblique factors. Guidelines were presented for consideration in the selection and reporting of rotational procedures in clinical research.

Factor Analysis, Statistical

An evaluation of the Briggs-Nebes modified version of Annett's handedness inventory.

The Briggs-Nebes (1975) modified version of Annett's (1967) handedness inventory was administered to 59 female and 51 male undergraduates and 101 nursing students. J-shaped distributions of scores in the dextral direction and significant sex differences such that males were more sinistral than females were found. The inventory was found to be multi-dimensional with up to three factors, power, skill, and rhythm in order of importance. The utility of the modified inventory was supported and recommendations were made concerning the use of subscale or factor scores in addition to overall scores.

Factor Analysis, Statistical

A psychometric investigation of the Eysenck Personality Questionnaire.

The Eysenck Personality Questionnaire was administered to 139 females and 123 males. Scale statistics were obtained and hierachial factor analyses were performed. The P scale was found to have low internal consistency reliabilities and to covary with the L scale in the female subsample. Factor analyses showed recovery of E scale items in a secondary factor, Social Extraversion, without an impulsivity primary factor. No P and N dimensions recovered; rather components of each scale interrelated in two meaningful dimensions at the tertiary level.

Adolescent

The State-Trait Anxiety Inventory A-Trait Scale: dimensions and their generalization.

The State-Trait Anxiety Inventory A-Trait scale was administered to 152 female and 158 male students. Principal-components factor analyses yielded four orthogonal factors for each sex. The findings indicated that factor pattern comparisons should be made prior to pooling data across sex for psychometric investigations. Also, limited support was found for the generalization of dimensions across sex and samples both within and between cultures.

Adjustment Disorders

Cautionary note on the use of short state-anxiety measures.

The report noted that the use of high item-remainder coefficients as the sole criterion in the selection of items for short state-anxiety scales from full scales can lead to inaccurate interpretation of results. It was demonstrated that the use of a four-item state-anxiety scale from the State-Trait Anxiety Inventory A-State scale based on high item-remainder coefficients changed relationships in a previously reported study which used full-scale scores. It was proposed that such changes in relationships were the result of selecting four items which happen to load on only one of three dimensions of the A-State scale. The criterion of high item-remainder coefficents alone may be inadequate in the formation of short state-anxiety scales.

Anxiety

Personality dimensions and reversible perspective in Embedded Figures Test.

The study examined the relationship between performance on reversible-perspective items in individual and group embedded-figures tests and remaining items, personality and performance variables in two samples of normal females. Performance on the reversible-perspective items was better than on the remaining items in the individual test and as good as other items in the group test. Those who experienced difficulty in solving the reversible-perspective items had more "psychiatric" complaints and greater sociability than subjects who experienced little difficulty.

Female

Components underlying the relation between field dependence and extraversion.

Components of Eysenck's Extraversion scale were examined to account for previous findings indicating that field independence, as measured by individual and group forms of the embedded-figures test, is associated with Introversion. In two of the three samples of female unversity students, field independence, as measured by the Group Embedded Figures Test, was associated with low impulsivity and slow decision time, as measured by items on Eysenck's Extraversion scale.

Extraversion, Psychological

Anxiety and perceptual articulation.

The study investigated Witkin's suggestion that low manifest anxiety is associated with relatively high perceptual articulation, whereas high anxiety is associated with relatively low perceptual articulation. Previous research typically has not provided adequate control for subjects' IQ; therefore, results may have been confounded by differences in subjects' ability. The study attempted to clarify the relationship between state and trait anxiety and perceptual articulation when IQ was controlled for 60 female subjects, who fell within a predetermined IQ range and were blocked into low, moderate and high A-Trait groups. Half of each group was assigned to either low or high ego-involving conditions. All subjects completed the Embedded-figures Test, Gestalt Completion and Concealed Words Test. Contrary to Witkin, the study yielded no significant relationship between anxiety and perceptual articulation.

Adolescent

Measurement of neo-Pavlovian properties of higher nervous activity by motor reaction-time tasks.

A preliminary study involving 80 paid subjects, 40 of each sex, investigated the usefulness of motor response-time tasks as measures of three neo-Pavlovian properties of higher nervous activity, excitatory strength, dynamism, and mobility. Six independent factors were extracted from a set of variables measuring those properties. These factors demonstrated the independence of the three properties, of the excitatory and inhibitory processes in dynamism and mobility, and of strength and sensitivity at least when such tasks are used as measures of properties in the auditory modality. These findings are promising, however, further investigation is required to validate these tasks against the classical tests of properties of higher nervous activity.

Acoustic Stimulation