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Biomedical subjects

S Perry

Publications and source records attributed to S Perry.

At least 145 records · Page 8Linked to original sources
PubMed1988

Color vision testing with a computer graphics system: preliminary results.

We report a method for computer enhancement of color vision tests. In our graphics system 256 colors are selected from a much larger range and displayed on a screen divided into 768 x 288 pixels. Eight-bit digital-to-analogue converters drive a high quality monitor with separate inputs to the red, green, and blue amplifiers and calibrated gun chromaticities. The graphics are controlled by a PASCAL program written for a personal computer, which calculates the values of the red, green, and blue signals and specifies them in Commité Internationale d'Eclairage X, Y, and Z fundamentals, so changes in chrominance occur without changes in luminance. The system for measuring color contrast thresholds with gratings is more than adequate in normal observers. In patients with mild retinal damage in whom other tests of visual function are normal, this method of testing color vision shows specific increases in contrast thresholds along tritan color-confusion lines. By the time the Hardy-Rand-Rittler and Farnsworth-Munsell 100-hue tests disclose abnormalities, gross defects in color contrast threshold can be seen with our system.

Adult↗
PubMed1988

Technology assessment in health care: the U.S. perspective.

Formal programs in medical technology assessment in the United States have become increasingly prominent in health care during the last 10 years in large part stimulated by remarkable technologic innovation, expansion in medical knowledge and increasing health care expenditures. The establishment of the Consensus Development Program of the National Institutes of Health initiated a decade of activities in technology assessment in both the public and private sectors and it was intensified by efforts to contain expenditures, particularly the Prospective Payment System. However, in spite of the wide range of evaluation activities, deficiencies remain which will have to be remedied if medical and policy decisions regarding technologies are to be made on sound bases.

Diffusion of Innovation↗
PubMed1988

Hospitalization stress in children: sensitizer and repressor coping styles.

To examine the effects of individual sensitizer/repressor coping styles on responses to hospital procedures, 56 children (mean age = 6.5 years) were observed during hospitalization for minor surgery. Although the sensitizer children, as classified by their mothers, did not differ from the repressor children on baseline measures including hospital preparation, they were more talkative, expressive, and active during hospital play observations. During blood tests and preoperative injections, the sensitizers, compared with the repressors, were reported by their mothers to observe the procedures, to seek additional information about the procedures, and to show more protest behaviors. Finally, the sensitizer children required fewer hours of intensive care.

Adaptation, Psychological↗
PubMed1988

Infants of depressed mothers show "depressed" behavior even with nondepressed adults.

To determine whether the "depressed" behavior (e.g., less positive affect and lower activity level) of infants noted during interactions with their "depressed" mothers generalizes to their interactions with nondepressed adults, 74 3-6-month-old infants of "depressed" and nondepressed mothers were videotaped in face-to-face interactions with their mothers and with nondepressed female strangers. "Depressed" mothers and their infants received lower ratings on all behaviors than nondepressed mothers and infants. Although the infants of "depressed" versus nondepressed mothers also received lower ratings with the stranger adult, very few differences were noted between those infants' ratings when interacting with their mother versus the stranger, suggesting that their "depressed" style of interacting is not specific to their interactions with depressed mothers but generalizes to their interactions with nondepressed adults as early as 3 months of age.

Adolescent↗
PubMed1988

Assessing competency in the physically ill: guidelines for psychiatric consultants.

Psychiatric consultants are increasingly asked to evaluate the competency of medically ill patients, but the absence of accepted guidelines and gaps in the law can make their task difficult. A model procedure for evaluating competency developed by the authors stresses the importance of conducting a complete clinical evaluation of the patient, prescribes interventions to clarify the role of the consultant for referring physicians, outlines medical and legal principles governing competency, and identifies the requirements of the consultant's note. Consulting psychiatrists cannot declare a patient legally incompetent; they can only give an opinion about the patient's apparent competency. They can withhold their opinion, however, until they have treated a psychiatric condition that may be affecting the patient's competency. Case vignettes illustrate the application of the guidelines.

Adult↗
PubMed1988

Sociodemographic and behavioral characteristics of HIV antibody-positive blood donors.

This paper describes the sociodemographic and behavioral characteristics of 173 blood donors who were confirmed by Western blot tests to have antibodies to human immunodeficiency virus (HIV), the etiologic agent for acquired immunodeficiency syndrome (AIDS). Seropositive donors were predominantly young, unmarried, and male, and major risk factors could be identified for almost all donors. However, more than 20 per cent of the study participants were women, and many participants were not aware that they were at risk of infection. The heterogeneity of the study population, the lack of awareness among many subjects of risk factors and self-exclusion procedures, and the high level of distress among many subjects after notification, emphasize the need for intensive, well-designed education and support programs.

Adult↗
PubMed1987

Early effects of tetraethylammonium chloride on the contractile properties of isolated rabbit basilar arteries.

The acute vascular effects of tetraethylammonium chloride (TEA) were examined on annular segments of rabbit basilar arteries. Contractions induced by the potassium channel blocker were compared with those obtained for potassium chloride, 5-hydroxytryptamine (5-HT) and norepinephrine (NE). The greater magnitude of the contractions was of the following order: [K+] greater than 5-HT greater than TEA greater than NE. High concentrations of TEA alone (10(-2) M) generated spontaneous oscillatory contractions in cerebral vessels that were normally quiescent. Low concentrations of TEA (10(-8)-10(-6) M), which had no vasomotor properties per se, enhanced the contractile response of submaximal concentrations of 5-HT (10(-7) M) and NE (3 X 10(-6) M) and attenuated the contraction produced by 60 mM [K+]. An increased vascular response to the amines was still evident up to 3 h after the addition of TEA despite frequent rinsing with fresh buffer solutions. On arteries precontracted with TEA (10(-2) M), but not high [K+], the subsequent addition of 5-HT (10(-7) M) still induced a powerful constriction. Repeated concentration-response curves for [K+] were reproducible and, in the presence of TEA (10(-8) or 10(-6) M), the curve was displaced to the right in a competitive manner. A higher concentration of TEA (10(-4) M) was devoid of any blocking properties on the [K+]-induced response whereas, at 10(-3) M TEA, the response was potentiated, as evidenced by a shift of the curve to the left. Interactions between TEA and the cumulative response to 5-HT were difficult to interpret. Repeated exposures of the artery to 5-HT resulted in an increased maximal response with each determination (EAm = 127 +/- 9% and 149 +/- 14% of control values following the second and third applications, respectively). With TEA (10(-6) M), the increase in the maximal contractile effect noted previously was not observed. Contractions induced by single concentrations of TEA (10(-2) M) or [K+] (60 mM) were calcium dependent, were abolished completely in a calcium-free medium, and were depressed by the calcium antagonist nimodipine. 5-Hydroxytryptamine-induced contractions (10(-5) M) were less sensitive to withdrawal of calcium from the extracellular medium (31 +/- 6% relative to the maximal response at 4 mM calcium). Hence, an acute reduction in potassium conductance in cerebrovascular smooth muscle produced by TEA has complex, concentration-dependent effects and reproduces only part of the spectrum of effects of cisternal injection of blood on cerebrovascular reactivity.

Animals↗
PubMed1987

AIDS dementia: a review of the literature.

Mental disturbances associated with acquired immunodeficiency syndrome (AIDS) are related not only to profound psychosocial stress, systemic diseases, and neoplasms or opportunistic infections within the central nervous system (CNS); they are also related to the direct neurotoxicity of the etiologic human immunodeficiency virus (HIV), producing an array of both insidious and acute affective, cognitive, and behavioral dysfunction that can mimic many neuropsychiatric disorders. The precise mechanism of this direct neurotoxicity is not known, nor have the frequency, clinical course, or methods of early diagnosis been clearly established; however, a critique of 56 clinical reviews or case reports regarding approximately 800 subjects suggest that at some point following infection an HIV-induced dementia is extremely common, as are marked histopathological changes throughout the CNS. Treatment strategies are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Oral nimodipine reduces prostaglandin and thromboxane production by arteries chronically exposed to a periarterial haematoma and the antifibrinolytic agent tranexamic acid.

The calcium antagonist nimodipine blocks the effects of many vasoconstrictors of cerebrovascular smooth muscle and may reduce the incidence of delayed cerebral ischaemia following subarachnoid haemorrhage though not necessarily by inhibiting the development of angiographic cerebral vasospasm. Post-haemorrhagic CSF contains abnormally large quantities of various eicosanoids that partly reflect enhanced production by cerebral arteries. Does nimodipine affect this process? The extra-arterial and intra-arterial production of PG6 keto-F1 alpha, PGE2, PGF2 alpha and TXB2 were measured in perfused common carotid arteries taken from rabbits in which the arteries had been ensheathed by blood clot in vivo for 7 days. All rabbits were given the antifibrinolytic agent tranexamic acid to retard resolution of the clot, and half were given oral nimodipine (2 mg/kg/day) for 10 days. Nimodipine significantly reduced the extra-arterial production of TXB2 during the third and fourth hours of perfusion and, less consistently, the production of PGF2 alpha, PGE2 and PG6 keto-F1 alpha. Lutrol, the solvent for nimodipine, had no such effect.

6-Ketoprostaglandin F1 alpha↗
PubMed1987

The psychodynamic formulation: its purpose, structure, and clinical application.

The authors present a brief written psychodynamic formulation that focuses on central conflicts, anticipates transferences and resistances, and helps guide all psychiatric treatments. After placing the presenting problem in the context of the patient's life and identifying nondynamic determinants of the psychopathology, the formulation explains the development of central conflicts and their repetitive effect on the patient's behavior. It concludes by describing how these conflicts will be manifested in treatment. Three sample formulations and their application are presented to illustrate the value of this clinical tool.

Conflict, Psychological↗