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At least 37 records · Page 2Linked to original sources
PubMed1990

Comparison of induction with and first hour of recovery from brief propofol and methohexital anesthesia.

Anesthesia and recovery during the first hour after propofol and methohexital anesthesia for termination of pregnancy, lasting about 12 min, were compared, the latter in a double-blind manner by means of psychomotor tests (coin counting and continuous auditory reaction time). Muscle movements and hiccups were seen significantly more frequently during methohexital inductions. No differences were seen regarding pain at the site of injection or apnea between the groups. At 15 min after the last dose of anesthetic, recovery after methohexital was ahead of that after propofol, but after 1 h, psychomotor performance was better in the propofol group. Side-effects during recovery were few, and incidences did not differ significantly. Although the difference in reaction time test was significant, it was hardly large enough to be of any clinical importance. Both drugs are useful for brief outpatient anesthesia, but smoother induction gives propofol an edge over methohexital.

Abortion, Induced↗
PubMed1986

Antisperm antibodies and circulating immune complexes of vasectomized men with and without coronary events.

We compared antisperm antibody and circulating immune complex (CIC) levels in serum samples from 101 vasectomized and 101 normal age-matched nonvasectomized men; 31 of each group had histories of coronary heart disease (CHD). Vasectomy and CHD status were treated as categorical independent variables in the two-way analysis of variance. Elevations of both systolic and diastolic blood pressures were significantly associated with age and body mass index but not vasectomy. Antisperm antibodies (immobilizing and agglutinating) were significantly associated with vasectomy (P less than or equal to .001); the incidences were similar in men with and without CHD. The CICs were significantly associated with vasectomy in a Staphylococcus aureus (FcSa) CIC assay (P less than or equal to .001) and a Raji cell CIC assay (P less than or equal to .05). A third CIC assay, the Clq binding assay, did not reveal a difference between any subgroups. Generally, CICs occurred more frequently in the CHD group by the FcSa assay and particularly the Raji cell assay (P less than or equal to .001). In summary, vasectomized men had a higher incidence and higher levels of circulating antisperm autoantibodies and CICs than did age-matched controls.

Antigen-Antibody Complex↗
PubMedDate not supplied

Five-year, multicenter study of a triphasic, low-dose, combination oral contraceptive.

A total of 4,342 women received a triphasic oral contraceptive combination containing levonorgestrel and ethinyl estradiol (Triphasil in the United States, Trinordiol in Europe) over a 5-year period, for a total of 70,282 cycles. Medication was begun on day 1 in the first cycle, with no backup contraception, and consisted of levonorgestrel (LNg) 50 micrograms + ethinyl estradiol (EE2) 30 micrograms for 6 days, LNg 75 micrograms + EE2 40 micrograms for 5 days, and LNg 125 micrograms + EE2 30 micrograms for 10 days. Twelve pregnancies occurred during the study, resulting in a Pearl Index of 0.22. Medication was missed in an overall total of 5,067 cycles (7.2%), and 9 of the 12 pregnancies were attributed by the investigators to misuse of the drug, resulting in a corrected Pearl Index of 0.06. Cycle control was excellent, bleeding irregularities were minimal, and the incidence of adverse experiences was low (generally less than 1% of total cycles). The results indicate that this triphasic combination, given in pharmacologic doses that are patterned after normal cycles, is a predictable, efficacious, well-tolerated, and accepted means of oral contraception.

Adolescent↗
PubMed1989

Hemodynamics during increased intraluminal pressure in the ileum of suckling swine.

Studies of intestinal hemodynamics during increased abdominal and intraluminal pressure in adult animals (canine and feline) have shown that blood flow is practically unchanged at pressures up to 35-40 mm Hg. In the young animal, however, decreased total intestinal blood flow has been shown at pressures of 15 mm Hg or greater. To help characterize the effect of intraluminal pressure on intestinal circulation, we have studied pressure-flow relationships in an isolated loop of terminal ileum in piglets 2-14 days of age (mean, 6.1 +/- 3.7 SD, n = 14) with a mean weight of 1,745 +/- 345 SD. Intraluminal pressure was increased from 0-50 cm of water pressure in 10-cm steps of two min' duration. Blood flow was reduced with every increase in intraluminal pressure and significantly reduced at pressures of 20 cm of water or more. The calculated peripheral vascular resistance increased with every increment of intraluminal pressure. Analysis of the relationship of arterial blood pressure to changes in blood flow suggests that blood flow reductions are greater in animals with lower blood pressure at every level of intraluminal pressure studied. Increased intraluminal pressure could be a mechanism of intestinal mucosal ischemia in the newborn, particularly affecting those with low arterial blood pressure.

Animals↗
PubMed1975

Renal function in experimental chronic hydronephrosis. I. Backflow studies with dextran.

By ligation of the ureter, causing partial ureteral stenosis, unilateral hydronephrosis was induced in 10 dogs. Renal function studies including creatine clearance and osmolality determination were performed both before and after the ureteral ligation. The renal function analysis after induction of hydronephrosis included pyelovenous and pyelolymphatic reflux studies, with deposition of dextran in the renal pelvis at different intrapelvic pressures. Analysis with respect to sodium, potassium, chloride and dextran in the thoracic duct lymph, peripheral blood and urine from the intact kidney were performed. The results show a reduction of the renal function in hydronephrosis, little transport of dextran via the lymph and blood, and no significant increase in the lymphatic transport of the studied ions on elevation of the intrapelvic pressure.

Animals↗
PubMed1985

Noninvasive evaluation of intracardiac pressures using Doppler ultrasound: a case study of panvalvular regurgitation.

Doppler velocity signals from regurgitant valve flow can be used to calculate pressure gradients across incompetent valves by a modification of the Bernoulli equation. Analysis of these gradients provides clinically useful, noninvasive information about cardiac chamber pressures. This study presents an unusual case of cardiomyopathy with panvalvular regurgitation which demonstrates the major methods of pressure analysis using Doppler signals from regurgitant valves.

Aortic Valve Insufficiency↗
PubMedDate not supplied

[Atrial natriuretic peptide, renin-aldosterone system and arterial pressure. Analysis by circadian rhythm measurement].

Six voluntary, clinically healthy, non-smoking, male subjects were studied to estimate and eventually quantify the role of the circadian rhythm of atrial natriuretic peptide and of the renin-aldosterone system in the conditioning and genesis of the circadian rhythm of arterial blood pressure. After a week of standard life condition, during the span of a day, with the subjects in constant supine position, venous blood samples were drawn every four hours, while arterial blood pressure was measured every two hours. Plasma levels of atrial natriuretic peptide, renin activity, and aldosterone were determined by radioimmunoassay. The time-related values of each variable were analysed by the "cosinor" method. The cosinor analysis shows a statistically significant (p less than 0.05) circadian rhythm for all variables studied. These data suggest an inverse relationship between the circadian rhythm of atrial natriuretic peptide and that of arterial blood pressure, with a chronological sequence in the atrial natriuretic peptide-plasma renin activity-aldosterone axis.

Adult↗
PubMed1988

Computation of derived diagnostic quantities during intermittent coronary sinus occlusion in dogs.

The haemodynamic responses to pressure controlled intermittent coronary sinus occlusion (PICSO) were recorded intraoperatively in dogs. After analogue-digital conversion the data for coronary sinus pressure were submitted to numerical analysis for detection of systolic and diastolic envelopes and their subsequent fitting by a non-linear model. From the model variables derived quantities, such as plateau and rise times, were constructed so as to resemble the most important features of coronary sinus pressure rise during each occlusion-release cycle. The derived quantities were then monitored during all consecutive cycles throughout the entire experiment. In each dog the measurements were taken during normal coronary artery perfusion, left anterior descending coronary artery infarction, and reperfusion. The analysis comprise time course, stability, and physiological correlates of the derived quantities, on some of which a closed loop regulation may be based. Predicted plateaus (systolic and diastolic) and mean integrals (systolic and diastolic) were found to be stable quantities which, on subaveraging of about five successive estimates, yielded a 10% accuracy on the mean. By contrast, the rise times required subaveraging of about 15 cycles to achieve the same relative stability. It is concluded that, on subaveraging, derived quantities lend themselves for closed loop regulation input. Thus this quantitative assessment of numerical coronary sinus pressure analysis, as obtained from animal data, may lay the basis for future human application.

Animals↗
PubMed1978

Vascular reactivity of isolated perfused kidneys from normotensive, renal hypertensive and spontaneously hypertensive rats.

By means of an isolated kidney perfusion technique, reactivities of renal body vessels to electrical stimulation of renal plexus and intravascular administrations of low dosed norepinephrine and epinephrine were determined in the spontaneously hypertensive rats of Wistar strain, normotensive Sprague-Dawley rats and Sprague-dawley rats with renal hypertension of the same sex and as equal as possible with respect to age and body weight. The basal vascular resistance as indicated by the perfusion pressure caused by the same rat of perfusion was significantly higher in the renal hypertensive group. Both electrical stimulation of the renal plexus and intravascular administrations of catecholamines caused a rise of perfusion pressure. Analysis of the dose-response relationship reveals that in the dose range used, the sensitivities to electrical stimulation and to norepinephrine are significantly higher in the normotensive than the hypertensive groups. The results indicate that structural change in the blood vessels is more important than the adrenergic actions of low intensity in the cause of high resistance of blood flow in hypertensive subjects at least in the kidney.

Animals↗
PubMed1987

Clinical evaluation of the Nippon Colin BP-103N blood pressure monitor.

The automatic oscillometric Nippon Colin BP-103N blood pressure-monitor was evaluated in comparison with the Hawksley random zero mercury sphygmomanometer using standard methods. The monitor under test was found significantly to over-read mean systolic pressures by 4.2 mmHg and mean diastolic pressures by 4.6 mmHg. The coefficient of variation was 5.4% for systolic and 6.4% for diastolic pressures. Analysis of variance showed that the difference between the two manometers was within the random variability of readings obtained.

Adult↗
PubMed1986

[Genetic and ecological study of aboriginal populations of northeastern Siberia. II. Polymorphic blood systems, immunoglobulin allotypes and other genetic markers in asian eskimos. Genetic structure of Bering sea eskimos].

Blood groups, immunoglobulin allotypes, serum proteins and red cell enzymes were tested in four populations of Asiatic Eskimos. 12 of 16 gene loci studied were found to be polymorphic. Analysis of covariance and variance matrices for gene frequencies of 8 Bering Sea populations revealed major aspects of regional genetic structure. Regression of average heterozygosity on genetic distance from centroid permitted us to interpret it in the light of counterbalancing action of systematic and non-systematic pressure. Analysis of R matrix containing gene frequencies for both Eskimo and Chukchi populations revealed two different clusters - more heterogeneous Eskimo cluster and less heterogeneous Chukchi cluster. Good fit was observed between regional genetic structure, history and geography.

Blood Group Antigens↗
PubMed1990

Differential anesthetic depression of chronotropic baroreflexes in rats.

To assess anesthetic alteration of chronotropic baroreflexes, arterial pressure and heart rate (HR) were monitored continuously during intravenous (i.v.) infusions of phenylephrine or sodium nitroprusside in rats that were either awake or anesthetized (with pentobarbital, urethane, or chloralose). Ensuing reflex HR responses during each drug infusion were determined in two ways: (a) at 10-s intervals (time analysis), and (b) with every 5-mm Hg change in pressure (pressure analysis). Results were less variable with pressure than with time analysis. With responses from awake rats as a basis for comparison, pressure analysis showed that pentobarbital greatly attenuated both reflex tachycardia and bradycardia, whereas urethane and chloralose reduced only reflex tachycardia. Depression by pentobarbital of both reflex tachycardia and bradycardia suggests severe attenuation of both sympathetic and parasympathetic tone. In contrast, preferential alteration of reflex tachycardia by chloralose and urethane implies a greater attenuation of sympathetic than parasympathetic tone.

Anesthesia↗
PubMed1986

Clinical observations on the relationship between cerebrospinal fluid pulse pressure and intracranial pressure.

A method is described for monitoring the relationship between CSF pulse pressure and ICP in clinical patients. Highly significant linear relationships were found during 65 continuous ICP recordings in 58 patients. The slope value of this relationship showed a positive correlation with the elastance coefficient, a volume-pressure parameter assessed by bolus injection. However, the correlation was too weak to allow for a confident prediction of the elastance coefficient on the basis of CSF pulse pressure in the individual patient. This was attributed to the variable magnitude of the volume change underlying the CSF pulse pressure: the pulsatile variation in cerebral blood volume. This quantity was calculated on the basis of a mathematical model from the slope value and the elastance coefficient and was found to vary between 0.36 and 4.38 ml. During plateau waves a disproportionate increase in pulse pressure with the ICP was observed in contrast with a relative decrease in intracranial elastance. This phenomenon was ascribed to an increase in the pulsatile variation in cerebral blood volume. It is concluded that, under certain conditions, the intracranial volume-pressure relationship can be continuously monitored by means of CSF pulse pressure analysis. The findings during plateau waves suggest that the pulse pressure also reflects the state of the cerebral vasomotor tone.

Adult↗
PubMed1990

Gas exchange across avian eggshells oscillates in phase with heartbeat.

Rahn et al. (J. Appl. Physiol. 69: 1546-1548, 1990) showed that the gas pressure in a plethysmograph containing an intact egg oscillates in phase with electrocardiogram (ECG) and that this pressure variation could be used as a noninvasive way to determine the heart rate of an avian embryo. One possible mechanism to account for the pressure oscillation is the mechanical movement of the embryonic heart, which leads to volume shifts of gas within the plethysmograph. Another possibility is that the oscillation of gas pressure with heartbeat is pulsatile gas exchange resulting from pulsatile blood flow. If gas exchange were transiently stopped, a pressure signal dependent on gas exchange should disappear, while a pressure signal dependent on cardiovascular motion should persist. Using a number of late-age hen eggs (at days 15-20 of incubation), we tested these hypotheses by suddenly changing the gas composition surrounding an egg and measuring the effect of the pressure oscillation. We found that 1) after 5% CO2-95% N2 was flushed into the plethysmograph (presumably halting gas exchange), pressure oscillations went almost to zero and the ECG signal remained; after air was flushed back to the plethysmograph, the pressure signal returned to control level; 2) after 20% CO2-20% O2-60% N2 was flushed into the plethysmograph (presumably increasing net gas exchange), the pressure signal increased 2.5-fold compared with that in air; and 3) after 1% CO2-99% N2 was flushed into the plethysmograph (presumably reversing gas exchange), the oscillation pressure decreased to one-fourth of that in air and the phase of pressure relative to ECG reversed compared with the phase in air.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pressure↗