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At least 541 records · Page 30Linked to original sources

PubMed1999

Risk factors accelerating cerebral degenerative changes, cognitive decline and dementia.

OBJECTIVES: Factors accelerating cerebral degenerative changes represent potentially modifiable risks for cognitive decline. Putative risk factors accelerating subtle cognitive decline and dementia were correlated with repeated measures of cerebral atrophy, CT densitometry, perfusions and cognitive testing among neurologically and cognitively normative ageing volunteers. METHODS: Two hundred and twenty-four normative subjects at increased risk for cognitive decline were admitted to the study. Mean entry age was 59. 5+/-15.8 years. Mean follow-up is 4.3+/-3.1 years. At follow-up, 22 developed subtle cognitive decline (deltaCCSE>/=-3), 19 became demented, eight with vascular type (VAD) and 11 with Alzheimer's type (DAT) and 183 remain cognitively unchanged. Standardized questionnaires, medical, neuropsychological, neurological and blood work examinations were obtained. Cerebral atrophy, tissue densities and perfusions were measured by xenon-enhanced CT. RESULTS: After age 60, cerebral atrophy, ventricular enlargement, polio- and leuko-araiosis geometrically increased as perfusions declined. Risk factors accelerating perfusional decline, cerebral atrophy, polio-araiosis and leuko-araiosis (thinning of grey-white matter densities) were: transient ischaemic attacks (TIAs), hypertension, smoking, hyperlipidemia, male gender. At age 71.5+/-11.9, subtle cognitive decline began, accelerated by TIAs, hypertension and heart disease. Leuko-araiosis began before cognitive decline. TIAs, hypertension and hyperlipidemia correlated with VAD. Excessive cortical perfusional decreases and cerebral atrophy correlated with cognitive decline. Family history of neurodegenerative disease correlated with DAT. CONCLUSION: TIAs, hypertension, hyperlipidemia, smoking and male gender accelerate cerebral degenerative changes, cognitive decline and dementia.

Adult↗

PubMed2000

Evaluation of an accelerated Caco-2 cell permeability model.

An accelerated 3-7-day Caco-2 cell permeability model was examined and compared to the traditional 21-25-day model. Caco-2 cell permeability coefficients (P(Caco-2)) of 33 structurally diverse small molecular weight compounds from apical to basolateral (AP-->BL) direction in the accelerated model were approximately twice those in the traditional model. As observed with microscopy and transepithelial electrical resistance measurements, this difference was attributed to less confluent and differentiated Caco-2 cell monolayers in the accelerated model. However, there were no significant differences in rank ordering of the compounds. The expression of P-glycoprotein in the accelerated model was shown to be significantly less than that in the traditional model. This resulted in lower permeability directional ratios defined as the ratio between permeability coefficients from BL-->AP and from AP-->BL for compounds that were cellular efflux pump substrates. The accelerated model may not be suitable for studying cellular efflux pumps such as P-glycoproteins. However, it is a feasible alternative to the traditional model for rank ordering of compounds in the process of drug discovery and development by significantly improving the turnover time and labor efficiency. This makes it an excellent Caco-2 cell permeability model for high throughput screening.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2000

Estimation of pressure gradients in pulsatile flow from magnetic resonance acceleration measurements.

A method for estimating pressure gradients from MR images is demonstrated. Making the usual assumption that the flowing medium is a Newtonian fluid, and with appropriate boundary conditions, the inertial forces (or acceleration components of the flow) are proportional to the pressure gradients. The technique shown here is based on an evaluation of the inertial forces from Fourier acceleration encoding. This method provides a direct measurement of the total acceleration defined as the sum of the velocity derivative vs. time and the convective acceleration. The technique was experimentally validated by comparing MR and manometer pressure gradient measurements obtained in a pulsatile flow phantom. The results indicate that the MR determination of pressure gradients from an acceleration measurement is feasible with a good correlation with the true measurements (r = 0.97). The feasibility of the method is demonstrated in the aorta of a normal volunteer. Magn Reson Med 44:66-72, 2000.

Adult↗

PubMed2001

Effects of temperature and concentration of the accelerators ethoxylated alcohols, diethyl suberate and tributyl phosphate on the mobility of [14C]2,4-dichlorophenoxy butyric acid in plant cuticles.

Intrinsic activities of monodisperse ethoxylated dodecanols (MEDs), diethyl suberate (DESU) and tributyl phosphate (TBP) were investigated using Stephanotis floribunda leaf cuticular membranes (CMs) and [14C]2,4-dichlorophenoxy butyric acid (2,4-DB) as a model solute. When sorbed in cuticular membranes, MEDs, DESU and TBP increase solute mobility and are called accelerators for this reason. With MEDs, dose-effect curves (log mobility vs accelerator concentration) were linear but, with DESU and TBP, curves convex to the x axes were obtained that approached a maximum at 90 and 150 g kg-1, respectively. Accelerators increased the mobility of 2,4-DB in the CMs by 9- to 48-fold, and effects were larger at lower temperatures (range 15-30 degrees C). Activation energy for diffusion of 2,4-DB was 105 kJ mol-1, decreasing with increasing accelerator concentrations to 26 kJ mol-1 with DESU at 90 g kg-1 and 64 kJ mol-1 with TBP at 150 g kg-1. Thus, the intrinsic activity of DESU was much higher than that of TBP, which implies that, for a given effect, less DESU than TBP would be needed. MEDs were also very effective accelerators, lowering activation energies to 36 kJ mol-1. Data are discussed in relation to increasing rates of foliar penetration of active ingredients at low temperatures.

2,4-Dichlorophenoxyacetic Acid↗

PubMed2005

Exo-mechanism proximity-accelerated alkylations: investigations of linkers, electrophiles and surface mutations in engineered cyclophilin-cyclosporin systems.

Investigations on the scope and utility of exo-mechanism proximity-accelerated reactions in engineered receptor-ligand systems are reported. We synthesized a series of electrophilic cyclosporin (CsA) derivatives by varying electrophiles and linker lengths, prepared a series of nucleophilic cysteine mutations on the surface of cyclophilin A (Cyp), and examined their reactivity and specificity in proximity-accelerated reactions. Acrylamide and epoxide electrophiles afforded useful reactivity and high specificity for alkylation of engineered receptors in Jurkat cell extracts. We found that remote cysteines (>17 A from the ligand) could be alkylated with useful rates under physiological conditions. The results from mutations of the receptor surface suggest that the dominant factors governing the rates of proximity-accelerated reactions are related to the local environment of the reactive group on the protein surface. This study defines several parameters affecting reactivity in exo-mechanism proximity-accelerated reactions and provides guidance for the design of experiments for biological investigations involving proximity-accelerated reactions.

Alkylation↗

PubMed1992

H-2-linked control of the Yaa gene-induced acceleration of lupus-like autoimmune disease in BXSB mice.

The accelerated development of lupus-like autoimmune disease in male BXSB mice (H-2b, I-E-) is associated to the presence of a mutant gene, designated Yaa, located on their Y chromosome. To investigate whether the H-2b haplotype and/or the lack of expression of I-E molecules play any role in the Yaa-linked acceleration of autoimmune disease, an I-E+ BXSB.H-2d congenic strain was created by backcross procedures. We compared the development of autoimmune disease in the novel BXSB.H-2d (I-E+) strain to that of BXSB.H-2b (I-E-) and BXSB.H-2b/d (I-E+) heterozygous mice. Male BXSB.H-2d (I-E+) mice exhibited only a limited production of autoantibodies and a lower incidence of glomerulonephritis with a markedly prolonged survival rate, which were essentially identical to those of female BXSB mice of both-H-2b and H-2d haplotypes. However, BXSB.H-2b/d (I-E+) heterozygous males developed an accelerated disease comparable to that of conventional BXSB.H-2b (I-E-) male mice. These results indicate that the expression of I-E molecules and consequent clonal deletion or anergy of I-E reactive T cells does not appear to be responsible for the prevention of accelerated autoimmune disease in BXSB.H-2d (I-E+) male mice. The finding that the Yaa gene-induced acceleration of lupus-like autoimmune disease is modulated by gene(s) within or closely linked to the H-2 complex underlines the crucial role of the major histocompatibility complex and the polygenetic nature of autoimmune disease in BXSB mice.

Animals↗

PubMed2003

Changes in particle area measurements due to SEM accelerating voltage and magnification.

Scanning electron microscopy (SEM) images of polymer blends followed by digital image analysis is a rapid and easy method for the measurement of particle size and dispersion. The particle size determination is done with appropriate off-line image analysis software. However, it is necessary to understand how machine parameters involved in the formation of the SEM image influence area measurements of morphological features. In this work, the influence of the accelerating voltage used during image acquisition was examined with standard samples and with polymer blend samples. A systematic study centered on two mutually exclusive assumptions of area variation or no area variation with accelerating voltage was carried out. The off-line image analysis software was then calibrated according to the assumptions. The main conclusion of this study was that kV has an important influence on area measurement in SEM images. This effect was observed for different standard materials (metallic and polymeric) and for the range of magnifications used. The higher the accelerating voltages, the greater the error at high magnification for polymer samples. As the beam energy increases, the primary electrons penetrate more deeply into the solid specimen, producing low-resolution signals. These signals degrade the image and surface details, which became less well defined. Therefore, images of polymer samples must be taken at lower accelerating voltages so the desired surface details can be imaged clearly. To avoid area measurement errors, particle measurement must be done with the calibration of the off-line image analysis software corresponding to the accelerating voltage and magnification used for the acquired images.

Image Processing, Computer-Assisted↗

PubMed2007

Relative risk and acceleration in lung cancer.

For a substance that increases the relative risk of disease, it does not necessarily follow that the proportion of cases due to exposure to the substance is the same as the attributable fraction in the exposed. An alternative explanation is that the substance has accelerated the occurrence of disease and, therefore, played a role in all cases. When the incidence of disease with time follows the Weibull distribution, it is well known that the proportional hazards model and the accelerated failure time model are equivalent. The purpose of this paper is to provide a numerical illustration of the relationship between the relative risk and the acceleration time of occurrence of cases. A Weibull distribution is a good approximation for lung cancer death rates up to the age of 80 years. The numerical relationship between the relative risk and the time by which cases are accelerated is given for lung cancer deaths occurring at ages of 40-75 years with relative risks of 1.01-3. As an example, for a death due to lung cancer at age 60 years in a smoker, relative risks of 2 and 1.1 due to occupational exposure to a substance correspond to accelerations of 5.2 years and 8 months, respectively.

Adult↗

PubMed1999

Estradiol accelerates extinction of lithium chloride-induced conditioned taste aversions through its illness-associated properties.

Estradiol accelerates extinction of LiCl-induced conditioned taste aversions when it is present during a period that starts 2-3 days after acquisition and extends throughout extinction (before and during extinction). It has been suggested that estradiol acts before, not during, extinction and that its effect on extinction is associated with its illness-inducing properties. This hypothesis is based on previous work which shows an attenuation of conditioned taste aversion learning when rats are exposed to illness-inducing agents during a period that starts 2 days after acquisition and ends 2 days before extinction trials are initiated. Four experiments were designed to test elements of this hypothesis. The first two experiments demonstrated that if an estradiol-filled Silastic capsule is implanted before extinction of a LiCl-induced aversion, when the conditioned taste is not present, it accelerates extinction, but if it is implanted during extinction, when the conditioned taste is present, it prolongs extinction. The third experiment showed that the same dose of estradiol that accelerates extinction of a LiCl-induced aversion was effective in producing a conditioned taste aversion when it was present for 18 h after consumption of a novel sucrose solution. The fourth experiment indicated that serum levels of estradiol were elevated during the 18 h. These results are consistent with the hypothesis that the acceleration of extinction by estradiol is associated with its illness-inducing properties. It is suggested that estradiol acts on neural areas that mediate illness information and that one of these areas, the area postrema is necessary for estradiol to accelerate extinction of a LiCl-induced aversion.

Analysis of Variance↗

PubMed1991

Head acceleration following linear translations in the freely-standing cat.

The aim of this study was to determine whether vestibular information related to head acceleration is available for triggering postural responses to perturbations of stance in the freely-standing cat. Linear accelerations of the head were recorded during postural responses evoked by linear translations of the support surface. A consistent initial peak of acceleration was observed at an average latency of 22 ms and magnitude of 0.03 g (g is acceleration due to gravity, 9.8 m/s/s). The acceleration peak preceded the first evoked EMG activity by an average of 24 ms. It was concluded that stimulation of the vestibular apparatus was both adequate and early enough for the vestibular system to have triggered the automatic postural response.

Animals↗

PubMed1984

Acceleration of cerebral noradrenaline turnover after morphine withdrawal and its retardation by acute morphine administration in rats.

To clarify the effects of withdrawal from chronic morphine treatment on cerebral noradrenaline (NA) turnover, we have measured the alpha-methyl-p-tyrosine (alpha MT)-induced depletion of NA in five brain areas of male Wistar rats given morphine twice daily for 40 or 60 days. After the last morphine dose (50 or 70 mg/kg) the rats were withdrawn for 1, 2 or 4 days. In order to study the development of tolerance a challenge dose of 10 mg/kg of morphine was given to some of the rats. Withdrawal of morphine accelerated the alpha MT-induced NA depletion clearly in the hemispheres and the lower brain stem and slightly in the diencephalon. The acceleration was more pronounced in the brains of rats treated for 60 days than of those treated for 40 days. In the hemispheres the acceleration of NA depletion occurred at 1 and 2 days, in the diencephalon at 2 days, and in the lower brain stem at 2 and 4 days after morphine withdrawal. The most pronounced acceleration of NA depletion coincided with the maximum withdrawal-induced weight loss. The challenge dose of morphine clearly retarded the alpha MT-induced NA depletion in the hemispheres of control rats treated chronically with saline. This retardation was even more pronounced in rats withdrawn from chronic morphine treatment for 1 or 2 days. The challenge dose slightly accelerated the alpha MT-induced NA depletion in the lower brain stem of control rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

Serum from Theileria sergenti-infected cattle accelerates the clearance of bovine erythrocytes in SCID mice.

Anemia is a major clinical sign of Japanese bovine theileriosis caused by Theileria sergenti. To investigate the possible factors causing anemia in cattle, we developed a clearance test for bovine erythrocytes (Bo-RBC) in severe combined immunodeficient (SCID) mice. Clearance of Bo-RBC in the SCID mice was significantly accelerated when the mice were inoculated with a serum sample obtained from an infected calf during a highly parasitized phase but not when they were injected with a serum sample obtained during the convalescence phase. Acceleration of the clearance of Bo-RBC was also observed in mice treated with merozoite extract. Furthermore, the clearance of Bo-RBC that had been treated with merozoite extract was accelerated. A significant hemolytic activity in infected serum (highly parasitized phase) was observed. Activities sufficient to accelerate the clearance of Bo-RBC in SCID mice and to induce in vitro hemolysis of Bo-RBC were also observed with a merozoite extract from T. sergenti. The results suggest a possible linkage between the in vitro hemolysis of Bo-RBC and the acceleration of Bo-RBC clearance in SCID mice.

Acute Disease↗

PubMed2005

Value of acceleration flow in the left anterior descending coronary artery for the detection of coronary artery stenosis by transthoracic coronary color Doppler echocardiography.

Whether the localized flow acceleration occurs in the resting stenotic left anterior descending coronary artery was explored and its value for detection of coronary stenosis estimated. Blood flow in the left anterior descending coronary arteries in 45 patients was detected by transthoracic color Doppler echocardiograph and multipoint pulse Doppler spectrums were recorded in the same segment. The ratio of the maximal peak diastolic velocity to the minimal peak diastolic velocity was calculated. The ratio > or = 1.5 was the cutoff value for the presence of localized acceleration flow. There were 23 patients with localized acceleration flow examined by echocardiography. Twenty of them were found to have luminal diameter stenosis (60% - 98%) in the left anterior descending coronary arteries by coronary angiography and 3 patients were normal. There were 22 patients without localized acceleration flow examined by echocardiography. Eighteen of them had no or < 60% stenosis. Four patients had serious stenosis (> or = 95%) or occluded segments in the left anterior descending coronary arteries on coronary angiography. The ratio of the maximal peak diastolic velocity to the minimal peak diastolic velocity was significantly higher in patients with left anterior descending coronary artery stenosis than that in those without stenosis (1.9 +/- 0.3 vs 1.3 +/- 0.2, P < 0.01) and it correlated significantly with left anterior descending coronary artery stenosis (r = 0.77, P < 0.01). The specificity by using the ratio > or = 1.5 for stenosis detection was 85.7% (18/ 21), and the sensitivity was 83.3% (20/24). This study demonstrated that local blood flow velocity was increased in the resting stenotic left anterior descending coronary artery. Transthoracic color Doppler echocardiography is a reliable noninvasive method to detect localized acceleration flow in the left anterior descending coronary artery stenosis and it is useful in the noninvasive diagnosis of stenosis in the left anterior descending coronary artery.

Adult↗

PubMed2000

An original accelerated radiotherapy schedule in stage III to IV head and neck cancers. Results in a multicenter setting.

BACKGROUND: Accelerated radiotherapy delivery has recently been shown to be effective in overcoming repopulation during fractionated radiotherapy. The therapeutic ratio may be particularly favorable for 5-week regimens. This study reports the feasibility and results of a particular accelerated schedule in Stage III to IV head and neck carcinomas used in a multicenter setting. PATIENTS AND METHODS: Seventy-four patients with Stage III (26 patients) or IV (48 patients) head and neck carcinomas were treated with a 5-week accelerated schedule (69.6 to 69.8 Gy in 41 to 40 fractions over a period of 35 to 36 days). Treatment began with 20 Gy in 10 daily fractions to initial involved sites, followed by bi-fractionated radiotherapy (2 x 1.6 Gy to 1.66 Gy/day) to a larger head and neck volume. Thirty-six (49%) patients received induction chemotherapy (median 3 cycles, range 1 to 4 cycles). RESULTS: Grade 3 or 4 (RTOG) confluent mucositis was observed in 57 patients (77%) and Grade 3 dysphagia in 33 patients (44%). Grade 3 or 4 (RTOG-EORTC) late complications were scored in 10.5% of cases. The 5-year actuarial locoregional control rate was 56% (95% CI: 42 to 71). The 5-year overall actuarial survival was 32% (95% CI: 18 to 46). Induction chemotherapy was not associated with a more favorable outcome. CONCLUSIONS: This study demonstrates the feasibility of this schedule in a multicenter setting. The oncologic results appear similar to those obtained by other accelerated regimens, while the rate of late complications seems acceptable. Five-week accelerated regimens warrant further evaluation, particularly in conjunction with concomitant chemotherapy, in the framework of prospective trials.

Actuarial Analysis↗

PubMed2005

Visualization of the site of the onset of ventricular depolarization by acceleration mode Tissue Doppler imaging technique.

Tissue Doppler imaging (TDI) is a relatively new echocardiographic technique that shows regional myocardial wall velocities. The aim of this study was to evaluate the potential value of acceleration mode TDI technique for the visualization of the origin of ventricular activation site using the model of right ventricular pacing. Twenty-seven patients with implanted permanent pacemakers were studied by acceleration mode TDI, 4 of these patients were pacemaker dependent. Parasternal and apical chamber views were recorded on video tape by using acceleration mode TDI technique during sinus rhythm with preserved atrioventricular conduction in 23 subjects who were not pacemaker-dependent, and also during right ventricular apical pacing in VVI mode in 27 subjects in whom pacing lower rate was increased if necessary. Fifty images recorded during sinus and pacing rhythm in cineloop were examined by two independent observers who were unaware of the rhythm patterns and by the same observer on two different occasions for localizing the site of onset of ventricular acceleration. The origin of ventricular activation during sinus rhythm started at basal septal part of the ventricle and during pacing started at apical part of the ventricle was considered as correct localizations. The origin of ventricular depolarization was correctly localized for 46 of 50 images (92%) and 44 of 50 images (88%) by the first and the second observers, respectively. Concordant results between observers appeared in 48 of 50 (96%) of images. The diagnostic accuracy of the concordant results was 44 of 48 (91.6%) images. The kappa for interobserver variability was 0.77 (p<0.001), and for intraobserver variability was 0.64 (p<0.001) and 0.63 (p<0.001) for the first and the second observers, respectively. These results suggest that acceleration mode TDI can be used to detect the initial ventricular excited position and seems to have a potential value for localizing of the origin of normal or abnormal myocardial depolarization.

Adult↗

PubMed1983

Influence of tachycardia cycle length and antiarrhythmic drugs on pacing termination and acceleration of ventricular tachycardia.

We examined the influence of ventricular tachycardia (VT) cycle length and antiarrhythmic drugs on the frequency of VT termination and acceleration by single and double extrastimuli and right ventricular burst pacing. In 57 patients, 89 episodes of sustained VT (32 control, 57 drug) were induced by programmed electrical stimulation. Overall, 60 of 89 (67%) episodes of ventricular tachycardia were terminated by means of programmed electrical stimulation. In patients with relatively slow ventricular tachycardia (VT cycle length greater than or equal to 350 msec) pacing terminated 37 of 44 (84%) episodes but terminated only 24 of 45 (51%) episodes of more rapid VT (VT cycle length less than or equal to 349 msec, p less than 0.005). Pacing successfully terminated VT in nine of 49 (18%) episodes using a single extrastimulus, 22 of 52 (42%) episodes using double extrastimuli, and 40 of 66 (61%) episodes using burst right ventricular pacing. VT acceleration occurred in none of 49 attempts with a single extrastimulus, in eight of 52 (15%) attempts with double extrastimuli, and in 12 of 66 (18%) attempts using burst right ventricular pacing. During therapy, the frequency of either ventricular tachycardia termination or acceleration did not change regardless of the pacing termination method used. However, by prolonging the mean VT cycle length from 311.1 +/- 82.2 msec to 401.9 +/- 103.5 msec (p less than 0.01), drugs increased the overall frequency of VT termination. We conclude that: (1) pacing terminates VT more frequently if the VT cycle length is long and if right ventricular bursts are used, (2) burst right ventricular pacing increases the risk of VT acceleration, and (3) drugs increase the frequency of ventricular tachycardia termination by prolonging VT cycle length but do not affect frequency of VT acceleration.

Adult↗

PubMed1991

Maintenance therapy with sucralfate in duodenal ulcer: genuine prevention or accelerated healing of ulcer recurrence?

We sought to compare the efficacy of sucralfate to placebo for the prevention of duodenal ulcer recurrence and to determine that the efficacy of sucralfate was due to a true reduction in ulcer prevalence and not due to secondary effects such as analgesic activity or accelerated healing. This was a double-blind, randomized, placebo-controlled, parallel groups, multicenter clinical study with 254 patients. All patients had a past history of at least two duodenal ulcers with at least one ulcer diagnosed by endoscopic examination 3 months or less before the start of the study. Complete ulcer healing without erosions was required to enter the study. Sucralfate or placebo were dosed as a 1-g tablet twice a day for 4 months, or until ulcer recurrence. Endoscopic examinations once a month and when symptoms developed determined the presence or absence of duodenal ulcers. If a patient developed an ulcer between monthly scheduled visits, the patient was dosed with a 1-g sucralfate tablet twice a day until the next scheduled visit. Statistical analyses of the results determined the efficacy of sucralfate compared with placebo for preventing duodenal ulcer recurrence. Comparisons of therapeutic agents for preventing duodenal ulcers have usually been made by testing for statistical differences in the cumulative rates for all ulcers developed during a follow-up period, regardless of the time of detection. Statistical experts at the United States Food and Drug Administration (FDA) and on the FDA Advisory Panel expressed doubts about clinical study results based on this type of analysis. They suggested three possible mechanisms for reducing the number of observed ulcers: (a) analgesic effects, (b) accelerated healing, and (c) true ulcer prevention. Traditional ulcer analysis could miss recurring ulcers due to an analgesic effect or accelerated healing. Point-prevalence analysis could miss recurring ulcers due to accelerated healing between endoscopic examinations. Maximum ulcer analyses, a novel statistical method, eliminated analgesic effects by regularly scheduled endoscopies and accelerated healing of recurring ulcers by frequent endoscopies and an open-label phase. Maximum ulcer analysis reflects true ulcer recurrence and prevention. Sucralfate was significantly superior to placebo in reducing ulcer prevalence by all analyses. Significance (p less than 0.05) was found at months 3 and 4 for all analyses. All months were significant in the traditional analysis, months 2-4 in point-prevalence analysis, and months 3-4 in the maximal ulcer prevalence analysis. Sucralfate was shown to be effective for the prevention of duodenal ulcer recurrence by a true reduction in new ulcer development.

Double-Blind Method↗

PubMed1976

Antepartum fetal heart rate and uterine activity studies: I. Preliminary report of accelerations and the oxytocin challenge test.

A series of 344 antepartum fetal heart rate studies in 209 high-risk patients is described. The importance of evaluation of accelerations of the fetal heart rate as well as periodic decelerations associated with uterine activity is demonstrated. Our data suggest that the absence of accelerations of the fetal heart rate during the recording period may be associated with increased perinatal morbidity. Late decelerations may occur in the same recording session as accelerations of the fetal heart rate. The association of late decelerations of the fetal heart rate with no accelerations during the recording session is highly suggestive of increased perinatal morbidity. In high-risk patients, accelerations of the fetal heart rate and no late decelerations with uterine activity are a reassuring finding, with 91 per cent of patients showing no increased perinatal morbidity.

Adolescent↗