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Biomedical subjects

D L Newman

Publications and source records attributed to D L Newman.

At least 19 recordsLinked to original sources
PubMed1996

Behavioral observations at age 3 years predict adult psychiatric disorders. Longitudinal evidence from a birth cohort.

BACKGROUND: This study provides, to our knowledge, the first empirical test of whether behavioral differences among children in the first 3 years of life are linked to specific adult psychiatric disorders: anxiety and mood disorders, antisocial personality disorder, recidivistic and violent crime, alcoholism, and suicidal behavior. METHODS: In a longitudinal-epidemiological study, 3-year-old children were classified into groups based on examiner observations of their behavior. At age 21 years, they were reassessed for psychopathologic functioning using standardized interviews based on DSM-III-R criteria. RESULTS: Although effect sizes were small, undercontrolled (includes children who are impulsive, restless and distractible) and inhibited (includes children who are shy, fearful, and easily upset) children differed significantly from comparison children in young adulthood. Under-controlled 3-year-olds were more likely at 21 years to meet diagnostic criteria for antisocial personality disorder and to be involved in crime. Inhibited 3-year-olds were more likely at 21 years to meet diagnostic criteria for depression. Both groups were more likely to attempt suicide, and boys in both groups had alcohol-related problems. Controls for family social class did not change the findings. CONCLUSION: Some forms of adult psychopathologic abnormality are meaningfully linked, albeit weakly, to behavioral differences observed among children in the third year of life.

Adolescent↗
PubMed1996

Contrast reduction using energy dependent intensifying screens.

The speed of intensifying screens, in particular rare earth screens, increases with beam energy. Using such a screen, the measured contrast of an aluminium disc, with optical densities in the linear region of the characteristic curve, was found to be significantly and consistently less than that calculated from the gamma of the film-screen combination for all tube potentials from 40 to 140 kVp. This contrast reduction effect can be explained in terms of the filtering action of the disc which increases the effective energy of the beam. Hence, the film-screen combination is exposed to X-rays which have different effective energies. This results in two characteristic curves of different speed. The contrast of the disc image is not dependent on the gamma of either curve, but an effective gamma which links the two curves. This effective gamma is less than the gamma of either curve. Contrast calculated using the effective gamma gave good agreement with the measured contrast of the disc image over the tube potential range examined.

Aluminum↗
PubMed1996

Psychiatric disorder in a birth cohort of young adults: prevalence, comorbidity, clinical significance, and new case incidence from ages 11 to 21.

Mental health data were gathered at ages 11, 13, 15, 18, and 21 in an epidemiological sample using standardized diagnostic assessments. Prevalence of Diagnostic and Statistical Manual of Mental Disorders (3rd ed. revised; American Psychiatric Association, 1987) mental disorders increased longitudinally from late childhood (18%) through mid-(22%) to late-adolescence (41%) and young adulthood (40%). Nearly half of age-21 cases had comorbid diagnoses; and comorbidity was associated with severity of impairment. The incidence of cases with adult onset was only 10.6%: 73.8% of adults diagnosed at age 21 had a developmental history of mental disorder. Relative to new cases, those with developmental histories were more severely impaired and more likely to have comorbid diagnoses. The high prevalence rate and significant impairment associated with a diagnosis of mental disorder suggests that treatment resources need to target the young adult sector of the population. The low new-case incidence in young adulthood, however, suggests that primary prevention and etiological research efforts need to target children and adolescents.

Adolescent↗
PubMed1990

What is evaluation: nurse decision-makers' perceptions of program evaluation.

This study investigates alternate reasons for conducting program evaluation in community health care settings and their relationship with information needs. One hundred and thirty-six community health nurses representing New York state associations were the decision makers used in the survey. Results indicated that the most frequent reasons cited for conducting program evaluation were accreditation and standard control. These were followed by need for information for formative program changes and aiding decision makers. Participatory and scientific evaluation purposes were rated last. When examining information sources, respondents were unable to differentiate needs on an independent item-by-item basis; all items were considered important. When asked, however, to select the most critical items of these sources, a pattern of needs was established. Decision makers felt that program goals, identification of staff concerns, and presentations of client opinions were the most crucial types of information.

Community Health Nursing↗
PubMed1990

Improving the use of evaluation in health settings: do data support and order of recommendation make a difference?

This study examined two variables associated with nurse decision makers' perceptions of the usefulness of program evaluation. The first variable represented amount of data support for recommendations; the second represented the order of presentation of supporting and nonsupporting recommendations. The sample of New York state nurses reflected two levels of decision makers: Supervised (staff nurses) and supervising (head nurses, supervisors, and directors). Results indicated that experience with decision making and order of presentation affected perceptions of recommendations and sufficiency of information.

Administrative Personnel↗
PubMed1990

Arterial tortuosity.

Vessel curvature or tortuosity has usually been ignored in haemodynamic studies of the vasculature, vessels are commonly assumed to be straight and axisymmetric. This assumption is generally not valid and even for those vessels which are relatively straight in early life, such as the abdominal aorta, there is a tendency to develop tortuosity with increasing age. This paper proposes a quantitative evaluation of tortuosity based on the standard deviation of the incremental displacements of the midline of a vessel. The tortuosity coefficients for the abdominal aorta were determined from the aortograms of 92 patients. For the majority of patients aged less than 40 years of age, the tortuosity coefficients were close to those expected for a straight vessel, i.e. less than 0.20. Above that age there is a rising incidence of tortuosity with, in some cases coefficients several times greater than those expected for the straight vessel case. This tortuosity is likely to be due to an aging of the vessel wall leading to loss of longitudinal stiffness. The haemodynamic implications of tortuosity are that it is likely to create flow profile asymmetries leading to abnormal wall shear stress and predispose the vessel to atherosclerosis. As a consequence tortuosity may be considered as a geometrical risk factor in the development of the disease.

Adolescent↗
PubMed1986

High frequency characteristics of the arterial system.

Pressure, flow and diameter were measured in the abdominal aorta of five anesthetized dogs during normal heart beats and heart beats with a superimposed impulse (generated by rapidly injecting a small volume of saline into the system). From Fourier analysis it was found that the impulse enhanced the amplitudes of the higher harmonics so that frequencies up to 80 Hz could be studied. Both the input impedance and apparent phase velocity above 20 Hz were independent of frequency and their average values were designated as characteristic impedance and true phase velocity. Average characteristic impedance for all five animals was 2.0 +/- 0.1 X 10(8) Nsm-5 and average phase velocity was 8.3 +/- 0.6 ms-1. Phase velocities calculated from characteristic impedance (1.76-2.39 X 10(8) Nsm-5) and from the slope of the pressure-diameter relation (0.102-0.25 X 10(-8) Nm-3) were similar to the true phase velocity as defined above (6.79-9.85 ms-1). It may be concluded that the input impedance converges to characteristic impedance and apparent phase velocity converges to phase velocity for high frequencies.

Animals↗
PubMed1984

Actions of cysteinyl leukotrienes in coronary, femoral and carotid vessels of the pig.

Coronary, femoral and carotid vascular beds of anaesthetised pigs were perfused with heparinised arterial blood using an extracorporeal perfusion system. Blood flow was measured in each vascular bed. Leukotriene (LT) D4 caused a dose-related reduction in flow in the left anterior descending (LAD) artery. LTs C4 and D4, angiotensin and noradrenaline caused dose-related reductions in flow in femoral and carotid vascular beds. High doses of LTD4 caused total cessation of blood flow in the LAD and femoral beds. In the femoral and carotid beds LTC4 but not LTD4 caused an initial increase followed by a prolonged reduction in flow. Indomethacin (1.4 X 10(-5) mol kg-1, i.v.) did not affect the vasoconstrictor action of LTs.

Angiotensin II↗
PubMed1983

Effects of intra-coronary administration of leukotriene D4 in the anaesthetized dog.

The left anterior descending coronary artery in anaesthetized greyhounds was perfused at constant pressure with blood pumped from the carotid artery. Phasic and mean coronary flow, left ventricular pressure, dP/dt, cardiac output, ECG, heart rate and systemic pressure were measured. Leukotriene (LT) D4 was administered into the left anterior descending coronary artery as a bolus injection. LTD4 caused dose-related reductions in coronary flow. Other parameters showed little immediate change although a gradual decrease in left ventricular pressure, dP/dt, cardiac output and systemic pressure occurred after administration of LTD4. Following intracoronary administration of LTD4 small surface haemorrhages were observed over the area perfused. The reduction in coronary flow was not inhibited by indomethacin.

Animals↗
PubMed1982

Effect of smooth muscle activity on the static and dynamic elastic properties of the rabbit carotid artery.

The variation of radius with pressure was measured in vitro in the carotid artery of ten rabbits. Experiments were performed without prior conditioning of the vessel, over an inflation-deflation cycle at pressures in the range 0 to 24 kPa during treatment with, and in the absence of noradrenaline (referred to as active and passive conditions). The effect of a step change in pressure (2.7 kPa) on the radius of the vessel was investigated on a further three specimens. Under passive conditions, the variation of the static and the real part of the dynamic incremental elastic modulus with pressure and stress was similar during both inflation and deflation. Under active conditions a large degree of pressure-radius hysteresis was observed. At physiological pressures smooth muscle activity was associated with a decrease in elastic modulus when compared to passive values at the same pressure or stress. At a stress above 2 x 10(5) N.m-2 yield of the constricted vessels was observed and on further inflation and subsequent deflation the pressure radius curve was identical to that obtained under passive conditions. We suggest that conditioning a vessel, by means of repeated inflation to a high pressure and deflation to zero pressure, before measuring its elastic properties may give misleading results when applied to the vessels of living animals.

Animals↗
PubMed1981

Impulse propagation in normal and stenosed vessels.

The propagation of a transient pressure impulse in a viscoelastic medium was investigated by experiments using water-filled latex rubber tubing and the aorta of anaesthetised dogs. A 5 ms pressure impulse was produced by the impact of a solenoid driven hammer. The propagation characteristics of the impulse (attenuation and propagation velocity) along the vessel were determined by means of a catheter-tip pressure manometer placed at various distances distal to the impulse generator. The presence of stenoses of varying degrees of severity resulted in reflection of the impulse and the appearance of reflected pulses whose magnitude depended on the stenotic severity. The experiments suggest that for the technique to be used in the detection of local reflecting sites such as might result from vascular occlusive disease, the lesions should occlude at least 70% of the lumen and should be no more than 0.20 m distal to the impulse generator.

Animals↗
PubMed1980

Influence of static and oscillatory pressure/strain on 131I-albumin uptake by the wall of the isolated pig thoracic aorta.

The uptake of 131I-albumin by the wall of the isolated pig thoracic aorta was investigated in vitro to achieve good control of the experimental conditions. The lumena of the arteries were perfused with a balanced salt solution (Hanks') containing the radioactively labelled albumin. Albumin flux was studied at three static intralumenal pressures, viz 6.7, 13.3 and 20 kPa (50, 100 and 150 mmHg) and uptake (normalised per unit dry tissue weight) was found to be approximately doubled on increasing the pressure from 6.7 to 20 kPa (50 to 150 mmHg). With a mean pressure of 6.7 kPa (50 mmHg) the uptake was studied in the presence of sinusoidal pressure oscillations of amplitude in the range 1.3 to 6.0 kPa (10 to 45 mmHg) at frequencies 1, 5 and 11 Hz. At each frequency the uptake was found to be dependent on the pressure amplitude. The dependence at 5 Hz was significantly stronger than at 1 Hz (P < 0.05) and although not significant there was a suggestion that the uptake was higher at 5 than 11 Hz. There was no significance and no suggestion of a difference at 1 and 11 Hz. The possible influence on uptake of the associated oscillatory wall shear component has been considered. The relevance of these findings to macromolecular transport and to the characteristic localisation of atheroma within the arterial tree is discussed.

Animals↗