Jugular bulb saturation and cognitive dysfunction after cardiopulmonary bypass.

Inadequate cerebral oxygenation during cardiopulmonary bypass may lead to postoperative cognitive dysfunction in patients undergoing cardiac operations. A psychological test battery was administered to 255 patients before cardiac operation and just before hospital discharge. Postoperative impairment was defined as a decline of more than one standard deviation in 20% of tests.

Effect of aging on cerebral autoregulation during cardiopulmonary bypass. Association with postoperative cognitive dysfunction.

Background: Age is a predictor of cognitive dysfunction after cardiac surgery, but the mechanism is unknown. The purpose of our study was to determine whether age-related decrements in cognition are associated with cerebral blood flow (CBF) autoregulation during cardiopulmonary bypass (CPB).

Methods And Results: Cognitive function testing was completed before surgery and before hospital discharge in 215 patients undergoing elective coronary artery bypass grafting (CABG) surgery.

Stimulus dimensions of the cold pressor test and the associated patterns of cardiovascular response.

Hemodynamics of the cold pressor response in relation to its pain and nonpain stimulus components were investigated in normotensive college men using the foot and forehead cold pressor tasks. Mechanisms of pain- and non-pain-related increases in blood pressure were analyzed as residual effects of concurrent changes in total peripheral resistance and cardiac output. The identified partial relationships suggested that the response pattern associated with pain included positive change both in cardiac output and in total peripheral resistance, whereas the nonpain-related response was limited to an increase in total peripheral resistance.

Clinical guidelines: proliferation and medicolegal significance.

Guidelines seeking to influence and regulate clinical activity are currently gaining a new cultural ascendancy on both sides of the Atlantic. Statutory agencies may be charged with developing clinical guidelines, and civil courts, in deciding actions in negligence, could be influenced by standards of care expressed in guideline statements. Clinical guidelines are not accorded unchallengeable status: they have been subject to careful scrutiny by British and American courts to establish their authenticity and relevance.

Differential patterns of dynamic cardiovascular regulation as a function of task.

In cardiovascular reactivity studies, interpretations of the processes supporting the blood pressure response may become problematic when systolic blood pressure, diastolic blood pressure, and heart rate all increase in response to a behavioral challenge. Therefore, in addition to evaluating these cardiovascular responses, this study examined cardiac output, total peripheral resistance and systolic time intervals derived from impedance cardiogram, electrocardiogram and phonocardiogram recordings during a speech stressor, a mirror tracing task, and a foot cold pressor test. All of the behavioral stressors elicited increases in blood pressure and heart rate, with the largest changes occurring during the overt speech.

Signal fidelity requirements for deriving impedance cardiographic measures of cardiac function over a broad heart rate range.

Our findings indicate that the impedance cardiogram spectrum extends from DC to 50 Hz. Any amplifier with an upper band limit less than 50 Hz can be expected to produce attenuation and distortion of the impedance cardiogram. This signal attenuation may be systematically enhanced under conditions of high heart rate when a greater proportion of signal energy will be in the upper frequency range of the impedance cardiogram spectrum.

The cold pressor test: vascular and myocardial response patterns and their stability.

The purposes of the present study were to compare the cardiovascular response patterns evoked by three versions of the cold pressor test (either forehead stimulation or hand or foot immersion) and to determine the reproducibility of the responses over a 2-week interval. Blood pressure, heart rate, stroke volume, cardiac output, total peripheral resistance, and systolic time intervals were obtained during rest and during the cold pressor test in 42 young men. Across conditions, the pressor response was supported by peripheral resistance increases with concomitant stroke volume decreases.

The stability of cardiovascular parameters under different behavioral challenges: one-year follow-up.

The stability of myocardial, peripheral vascular and systolic time-interval measures was assessed over a one-year period in a sample of ten healthy normotensive men. Subjects participated in three laboratory sessions, the first two of which were two weeks apart, and the third approximately one year later. Measures were sampled during the preparation and delivery of a speech, a mirror star tracing task, and the forehead cold pressor test.

Prompting the clinical care of non-insulin dependent (type II) diabetic patients in an inner city area: one model of community care.

Objective: To evaluate the effectiveness and acceptability of centrally organised prompting for coordinating community care of non-insulin dependent diabetic patients.

Design: Randomised single centre trial. Patients allocated to prompted care in the community or to continued attendance at hospital diabetic clinic (controls).

Myocardial and peripheral vascular responses to behavioral challenges and their stability in black and white Americans.

The purpose of this study was to assess the short term stability of myocardial and peripheral vascular responses to behavioral challenges, and to compare the response patterns of Black and White men. Blood pressure and heart rate, as well as stroke volume, cardiac output, total peripheral resistance, and systolic time interval measures derived from the impedance cardiogram were obtained in 12 Black and 12 White men. These measures were taken prior to and during an evaluative speech stressor, a mirror star tracing task, and a forehead cold pressor test presented during two laboratory sessions scheduled two weeks apart.

Sensorimotor and cognitive consequences of middle cerebral artery occlusion in rats.

Rats were subjected to either right proximal middle cerebral artery (MCA) occlusion or sham operation, and examined for an extended period on a battery of tests designed to measure simple motor function, sensorimotor integration and cognitive function. Rats with MCA occlusion showed extensive neuronal loss in the dorsolateral striatum and variable neuron loss in the parietal, temporal and frontolateral neocortex. MCA occluded animals exhibited significant impairments in tests of postural reflex, visual and tactile forelimb placing, locomotor coordination, and a test of simultaneous bilateral tactile extinction.

Amphetamine promotes recovery from sensory-motor integration deficit after thrombotic infarction of the primary somatosensory rat cortex.

The present studies were undertaken to examine 1) whether d-amphetamine sulfate administered to rats well after thrombotic infarction of the vibrissal cortical barrel-field within the primary somatosensory cortex affected the rate and completeness of behavioral recovery and 2) whether a dose-response relation exists between d-amphetamine sulfate dose and recovery of function. In a learning task requiring sensory-motor integration, 41 rats were trained to perform a motor response in a T-maze consequent to the detection of a vibrissal deflection cue. Once training was complete, unilateral (n = 29) or sham (n = 12) infarction was produced by a noninvasive photochemical technique.

Sympathoadrenal preganglionic neurons in the adult rabbit send their dendrites into the contralateral hemicord.

Sympathetic preganglionic neurons projecting to the adrenal medulla of the adult rabbit were retrogradely labelled with horseradish peroxidase. Preganglionic neurons were located in thoracic spinal cord segments T3-T12, peaking in number at T8, and only ipsilateral to the side of injections. However, retrogradely labelled dendritic processes of preganglionic neurons in the intercalated nucleus pars paraependimalys, the intercalated nucleus, and possibly even in the intermediolateral cell column, were observed in the contralateral hemicord.

Sensory-motor deficit and recovery from thrombotic infarction of the vibrissal barrel-field cortex.

The present studies were undertaken to examine: (1) whether thrombotic infarction of the vibrissal cortical barrel-fields of the primary somatosensory cortex would produce behavioral consequences reflecting a sensory-motor deficit; and (2) whether there was any recovery of function up to two months after infarction. Specifically, in two different learning tasks requiring sensory-motor integration, rats were trained to perform a motor response consequent to the detection of vibrissal cues derived from either active exploration or from passive detection of vibrissal deflection. Once training was complete, unilateral, bilateral or sham-infarction restricted to the region of the primary somatosensory cortex was produced by a non-invasive photochemical technique, which induces platelet-activated vascular occlusion combined with blood-brain barrier changes and subsequent cell death.

Detection of sequences homologous to human retroviral DNA in multiple sclerosis by gene amplification.

Twenty-one patients with multiple sclerosis, chronic progressive type, were examined for DNA sequences homologous to a human retrovirus. Genomic DNA from peripheral blood mononuclear cells was analyzed for the presence of homologous sequences to the human T-cell leukemia/lymphoma virus type I (HTLV-I) long terminal repeat, 3' gag, pol, and env domains by the enzymatic in vitro gene amplification technique, polymerase chain reaction. Positive identification of homologous pol sequences was made in the amplified DNA from six of these patients (29%).

Blood pressure during induction and termination of the dorsal immobility response.

Evidence has indicated that afferent baroreceptor input may play a role in the induction of the dorsal and tonic immobility responses, which are behaviorally similar, but involve opposite posture changes upon induction (i.e., upright versus inverted, respectively).