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At least 19 recordsLinked to original sources
PubMed1975

Diastolic time intervals in ischemic and hypertensive heart disease: A comparison of isovolumic relaxation time and rapid filling time with systolic time intervals.

Isovolumic relaxation time (IVRT) and rapid filling time (RFT) were used to evaluate elasticity and compliance in 11 control subjects (Group 1), in nine patients with angina (Group 2), in 11 with hypertensive heasrt disease (Group 3), and in ten patients with healed myocardial infarction (Group 4). Pre-ejection period (PEP), pre-ejection period index (PEPI), left ventricular ejection time (LVET), left ventricular ejection time index(LVETI) and PEP/LVET ratio were all derived from simultaneous recordings of phonocardiograms, ECGs, apexcardiograms, and external carotid arterial pulses. No patients were in congestive heart failure and none were receiving medication. LVET and LVETI were the same in control patient groups; PEP was slightly increased in patients with healed myocardial infarctions (p smaller than 0.05); and PEPI was prolonged in the patients with angina (p = 0.001). THE PEP/LVET ratio too was different from the control group in patients with angina and hypertension (Groups 2 and 3-p smaller than 0.02 and smaller than 0.05 respectively). The diastolic time intervals were significantly altered in that the IVRT was prolonged in angina patients (113.4 equals or minus 28.3 msec), compared to control patients (85.7) equal or minus 18.4 msec). It was found that in 6 out of 9 patients with angina, this interval exceeded the highest normal value (108 msec), but that in only one out 11 patients with HCVD and in three out of ten with healed infarctions, was the interval prolonged. RFT was increased in HCVD (113.8 equals or minus 18.8 msec) and in healed myocardial infarction (123.8 equals or minus 30.0 msec) patients, compared to the control group (94.5 equals or minus 12.8 msec). Diastolic time intervals reflecting disorders in elasticity and compliance may occur in conjunction with alterations in systolic time intervals.

Adult↗
PubMed1998

[Prothrombin time and thromboplastin time. On-site measurement of the prothrombin time and activated partial thromboplastin time of surgical patients with laser photometry].

UNLABELLED: Turnaround time for analysis of prothrombin time (PT) and activated partial thromboplastin time (APTT) by standard laboratory methods ranges between 40 min and several hours. The delay in obtaining the test results limits their clinical utility for treatment of perioperative coagulation disorders and adequate anti-coagulation therapy. In this study, we compared on-site coagulation testing (OCT) of whole blood, which takes about 3 min, with standard laboratory plasma coagulation tests by our institutional laboratory (LAB) to assess the accuracy of the OCT in a clinical setting (abdominal and postcardiac surgery). METHODS: PT of 62 patients with abdominal surgery was measured intra- and postoperatively using both LAB (KC 40, Thromborel S, Centeon) and OCT (CoaguChek Plus, Boehringer Mannheim) systems. APTT was determined by LAB-(KC 40, Pathromtin, Centeon) and OCT-methods in 53 patients who underwent cardiac surgery requiring cardiopulmonary bypass. RESULTS: Linear regression demonstrated a strong and significant (p = 0.0001) correlation of OCT- and LAB-determinations both for PT (r = 0.92) and APTT (r = 0.91). For PT testing, bias analyses showed an agreement between OCT- and LAB-International Normalized Ratio (INR) (bias = 0.24; relative error = 14.6%) that was considered clinically acceptable, with 95% of the INR-differences lying between -0,26 and +0,74 (mean +/- 2 SD). Although commercial APTT-reagents usually differ in their sensitivity to heparin, we also found an acceptable agreement between OCT- and LAB-APTT values (bias = 6.7 s +/- 22 s; mean +/- 2 SD; relative error = 12%). CONCLUSION: On-site coagulation monitoring provides a rapid, convenient, and accurate assessment of coagulation that can both guide specific anti-coagulation therapy and optimize therapy control of coagulation disorders after cardiac and abdominal operations. As a consequence, OCT offers a valuable tool to reduce the inappropriate use of fresh frozen plasma and to improve cost-effectiveness.

Humans↗
PubMed1975

Genetics of susceptibility to plasmacytoma induction. I. BALB/cAnN (C), C57BL/6N (B6), C57BL/Ka (BK), (C times B6)F1, (C times BK)F1, and C times B recombinant-inbred strains.

Plasmacytomas were found in 58% of 373 BALB/cAnN (C) mice given three 0.5-ml doses of mineral oil (Bayol F or light mineral oil) or 2,6,10,14-tetramethylpentadecane (pristane) ip. The incidence of plasmacytomas in C57BL/6N (B6), C57BL/Ka (BK), (C times B6)F1 and (C times BK)F1 was 6.4, 0, 11.5, and 16.5%, respectively. The plasmacytomas occurred in old B6 mice, in contrast to their early appearance in strain C mice. The incidence of plasmacytomas in mineral oil-treated or pristane-treated C times B recombinant-inbred (Rl) strain mice was 28.3% in C times BD, 17.5% IN C times BE, 36.5% IN C times BG, 0% in C times BH, 2.9% in C times Bl, 48% in C times BJ, and 4.3% in C times BK. C times BD, C times BG, and C times BJ strains were considered susceptible to plascytoma induction by mineral oil or pristane; C times BE had a low susceptibility, and C times BH, C times Bl, and C times BK were resistant. The results suggested that there were only a few gene difference between C and B6 or BK that determined susceptibility or resistance to plasmacytoma induction, and that B6 and BK have at least one dominant resistance gene. The distribution pattern of susceptibility and resistance in the C times B Rl strains suggested the presence of a resistance gene on chromosome 9, linkage group II.

Age Factors↗
PubMed1999

Estimation of post-lead-time survival under dependence between lead-time and post-lead-time survival.

Early detection of cancer by screening advances the date of diagnosis, but may or may not alter time to death. Screening programme need to assess the true benefit of screening, that is, the length of time by which survival has been extended, beyond merely the time by which the diagnosis is advanced (lead-time). One method is to estimate the distribution of the time survived post-lead-time using total survival time data for screen-detected cancer cases, under the assumption of independence of the lead-time and the past-lead-time survival. However, it seems biologically reasonable that the lead-time and the post-lead-time survival are positively correlated. This paper investigates the consequences of departures from independence of lead-time and post-lead-time survival on estimation of post-lead-time survival. We introduce a new model that involves dependence between the lead-time and the post-lead-time survival. We show that the new model can be converted to the model discussed by Xu and Prorok. We consider the non-parametric maximum likelihood estimator of the post-lead-time survival under the new model. We apply the method to data from the HIP (Health Insurance Plan of Greater New York) breast cancer screening trial. We make comparisons with the survival of cancer cases not detected by screening, such as interval cases, cases among individuals who refused screening, and randomized control cases.

Breast Neoplasms↗
PubMed1989

[Nucleation time and growth time in patients with cholesterol gallstone--factors affecting nucleation time and growth time and effect of UDCA and CDCA].

Nucleation time (NT) and growth time (GT) were measured in gallbladder bile of patients with cholesterol gallstones. NT was significantly shortened (NT less than 10 days) in pure cholesterol stones but was moderately shortened (11 less than or equal to NT less than or equal to 21) in mixed and combination stones. GT also was accelerated (GT less than 7 days) in cholesterol stones. NT was shortened in increased biliary total protein, but on the contrary, was shortened in decreased apo A-I. NT of bile by UDCA therapy but not CDCA was extended. This suggests that increased apo A-I during UDCA therapy might imply extension of NT. The strong negative correlation between GT and CSI of bile suggests that CSI plays an important role in crystal growth.

Aged↗
PubMed1999

Relying solely on historical surgical times to estimate accurately future surgical times is unlikely to reduce the average length of time cases finish late.

STUDY OBJECTIVE: To determine whether using only previous cases' surgical times for predicting accurately surgical times of future cases is likely to reduce the average length of time cases finish late (after their scheduled finish times). DESIGN: Computer simulation. MEASUREMENTS AND MAIN RESULTS: Data from an operating room (OR) information system for two surgical suites were analyzed. For each case performed in fiscal year 1996, we searched backward for 1 year and counted the number of previous cases that were the same type of procedure performed by the same surgeon. Then, for each suite, surgical times were fitted to a statistical model estimating the effect of the type of procedure and who the surgeon was on surgical time. The estimated "variance components" were used in Monte-Carlo computer simulations to evaluate whether a hypothetical increase in the number of previous cases available to estimate the next case's surgical time would improve scheduling accuracy. Predictions of how long newly scheduled cases should take were impaired because 36.5% +/- 0.4% (mean +/- SE) of cases at a tertiary surgical suite and 28.6% +/- 0.7% of cases at an ambulatory surgery center did not have any cases in the previous year with the same procedure type and surgeon. Computer simulation was used to generate additional hypothetical cases. Using this data, even having many previous cases on which to base predictions of future surgical times would only decrease the average length of time that cases finish late by a few minutes. CONCLUSION: An OR manager considering using only historical surgical times to estimate future surgical times should first investigate, using data from their own surgical suite, what percentage of cases do not have historical data. Even if there are sufficient historical data to estimate future surgical times accurately, relying solely on historical times is probably an ineffective strategy to have future cases finish on time.

Ambulatory Surgical Procedures↗
PubMed1986

"Haemostasis time", a modified bleeding time test and its comparison with the Duke and Ivy/template bleeding times. I. Normal values, application in thrombocytopenic patients and evaluation of heparin and aspirin effects.

The occlusion time ("haemostasis time" - HT) of a thin, short cannula inserted into the cubital vein, was compared with the skin bleeding times of the Duke and Ivy/template techniques. 25 male and 25 female volunteers without a history of bleeding were divided into 5 equally large age groups ranging from 10 to over 50 years of age. They exhibited a range of 46 s-6 min 38 s (95% tolerance interval), while the Duke and Ivy/template bleeding times, which were simultaneously determined, corresponded to values given by other authors. HT is different from the skin bleeding times in that endothelium is replaced by a standard foreign surface which allows better standardization of the method. Similar results were obtained with HT compared to the skin bleeding times. These and a similar, non-significant heparin response with all three techniques suggest that HT is not more influenced by clotting factors than the Duke and Ivy/template bleeding times and, indeed, may be regarded as a bleeding time modification. HT, like both of the skin bleeding times, reflected lowered platelet counts and is even more sensitive in this respect. As tested in a group of 20 male and 20 female volunteers, HT showed a significant prolongation two hours after ingestion of 1 g aspirin. While male individuals exhibited longer bleeding times than females with the Ivy/template technique (sex-related difference p = 0.01), no male to female differences were found both with HT and the Duke bleeding time. HT is easy to perform, inexpensive, leaves no scars and is safe even for the patient with severe bleeding. Moreover, compared to the skin bleeding times, it permits a differential evaluation of vessel wall and tissue effects.

Adolescent↗
PubMed1992

On the relation between time perception and the timing of motor action: evidence for a temporal oscillator controlling the timing of movement.

Studies of time estimation have provided evidence that human time perception is determined by an internal clock containing a temporal oscillator and have also provided estimates of the frequency of this oscillator (Treisman, Faulkner, Naish, & Brogan, 1990; Treisman & Brogan, 1992). These estimates were based on the observation that when the intervals to be estimated are accompanied by auditory clicks that recur at certain critical rates, perturbations in time estimation occur. To test the hypothesis that the mechanisms that underlie the perception of time and those that control the timing of motor performance are similar, analogous experiments were performed on motor timing, with the object of seeing whether evidence for a clock would be obtained and if so whether its properties resemble those of the time perception clock. The prediction was made that perturbations in motor timing would be seen at the same or similar critical auditory click rates. The experiments examined choice reaction time and typing. The results support the hypothesis that a temporal oscillator paces motor performance and that this oscillator is similar to the oscillator underlying time perception. They also provide an estimate of the characteristic frequency of the oscillator.

Adult↗
PubMedDate not supplied

Influence of fibrinogen degradation products on thrombin time, activated partial thromboplastin time and prothrombin time of canine plasma.

To investigate how thrombin time, activated partial thromboplastin time (APTT) and prothrombin time are influenced by fibrinogen degradation products (FDP), different concentrations (0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8 and 1.0 mg/ml) of the purified FDP X, Y, D and E were added to the plasma of healthy dogs. If fragment Y was added to the plasma a considerable inhibitory effect could be demonstrated for all three test systems. A significant prolongation (p < 0.05) was found for concentrations of > or =0.1 mg/ml (thrombin time, APTT) and > or =0.2 mg/ml (prothrombin time). With FDP Y concentrations from >0.185 mg/ml (prothrombin time) to >0.24 mg/ml (APTT) coagulation time was prolonged beyond the respective reference range. As regards the other fragments, a comparable inhibitory effect could only be shown for fragment X added to the thrombin time test system. This effect can most probably be explained by the competition of the FDP X and fibrinogen for the fibrinogen binding sites of thrombin, rather than by a fibrin polymerization disorder. The results demonstrate that for plasma with normal fibrinogen concentration the group tests are only prolonged beyond the reference range at FDP concentrations very rarely found in spontaneous hyperfibrinolysis.

Animals↗
PubMed1988

"Haemostasis time", a modified bleeding time test and its comparison with the Duke and Ivy/template bleeding times. II. Application in bleeding disorders.

"Haemostasis time" (HT), the occlusion time of a Butterfly 25 short cannula inserted into the cubital vein, is a bleeding time modification comparable to the skin bleeding times according to Duke and Ivy/Mielke. It also measures platelet function and is not influenced more than the latter tests by clotting factors. In HT, subendothelium is replaced by a standard artificial surface. The technique was investigated in patients with haemophilia A and B, von Willebrand's disease (vWD), and defects of factors VII and XI. HT was prolonged in 9/16 patients with haemophilia A/B, but did not correlate with the factor VIII:C/IX:C values. However, it reflected the different bleeding tendencies in those patients as represented by early or late onset of bleeding symptoms and occurrence of spontaneous haemarthroses. Of the vWD patients, not classified by multimeric analysis, 15/31 had prolonged Simplate II bleeding times, 14/31 prolonged HTs. Only 20/31 patients had corresponding normal or prolonged bleeding times with both techniques. HT correlated significantly with the Duke bleeding time (p = 0.011), ristocetin cofactor activity (p = 0.003) and von Willebrand factor antigen (p = 0.022), while no correlations were found between these parameters and the Simplate II method. Statistical evaluation shows, that in vWD, HT can replace the less precise Duke bleeding time but not the non-related Ivy/Simplate techniques.

Adolescent↗
PubMed1999

Regaining lost time: adult aging and the effect of time restoration on recall of time-compressed speech.

Two experiments in which time was restored to artificially accelerated (time-compressed) speech are reported. Experiment 1 showed that although both young and older adults' recall of the speech benefited from the restoration of time, time restoration failed to boost the older adults to their baseline levels for unaltered speech. In Experiment 2, either 100% or 125% of lost time was restored by inserting pauses, either at linguistic boundaries or at random points within the passages. Experiment 2 showed that the beneficial effects of time restoration depended on where processing time was inserted, as well as how much time was restored. Results are interpreted in terms of age-related slowing in speech processing moderated by preserved linguistic knowledge and short-term conceptual memory.

Adult↗
PubMed1997

[Historical times, physical times, epidemiological times: probable contributions of Fernand Braudel and Ilya Prigogine to epidemiological thinking]

The text is an approach on time as a scientific category in epidemiology. Considering the aphorism time-place-person, time is pointed out as an element with little theoretical concern, despite its presence in main epidemiological concepts. While a topic connected to important changes in other disciplines, such as history, geography, biology and physics, time represents an interesting point of view to the interdisciplinary dialogue and its relevance for a critical knowledge in epidemiology. To argue about this idea, the historical and physical time constructions of Fernand Braudel and Ilya Prigogine are presented. These time theoretical constructions are compared with a probable epidemiological time. Finally, using the emerging infectious diseases as an example, some considerations are made about an apparent epistemological inadequacy of the epidemiological time to recognize the social and historical aspects involved in the complexity of the disease expressions in human populations.

Journal Article↗
PubMed2002

The cerebellum: it's about time! But timing is not everything--new insights into the role of the cerebellum in timing motor and cognitive tasks.

Converging evidence from different research studies supports a role for the cerebellum in timing neural processes. The cerebellum is part of a distributed system for motor control. The timing hypothesis provides a specific functional role for the unique contribution of the cerebellum. The timing capabilities of the cerebellum appear to extend beyond motor control into tasks focusing on perceptual processing that require the precise representation of temporal information and sensorimotor learning. Behavioral and modeling studies suggest that the cerebellar timing system is best characterized as providing a near-infinite set of interval-type timers rather than as a single clock with pacemaker or oscillatory properties, but this is controversial. In addition to learning precisely timed motor responses, the cerebellum is involved in on-line processing using feed-forward systems for which sensory input is used prior to movement execution to improve movement accuracy. This would be a mechanism for triggering accurate "time." The cerebellum continues to fascinate scientists, and although survival is possible without the cerebellum, the resultant quality of life is significantly compromised with clumsiness, ataxia, hypotonia, dysarthria, slowing of various cognitive perceptual processes, and impaired fine motor and ocular-motor coordination. The last three decades have seen the development of research that has focused on how the cerebellum functions. Further neurophysiologic research in cerebellar cortical neurotransmission is likely to further our understanding of the cerebellar contribution to timing sensorimotor processes.

Animals↗
PubMed1982

[More accidents due to daylight saving time? A comparative study on the distribution of accidents at different times of day prior to and following the introduction of Central European Summer Time (CEST) (author's transl)].

In the summer of 1980 for the first time clocks in the Federal Republic of Germany were advanced 1 h ahead of Central European Time (CET), which had been in use until then. In a sample of a total of 1070 accident patients, who had accidents on data pairs taken from the months of May 1979 (before the introduction of the so-called Central European Summer Time- CEST) and May 1980, comparable by day of the week, holiday, and weather conditions, and were seen at the University of Heidelberg Dept. of Surgery, a statistically significant increase in accident frequency between 7:30 p.m. and 5:30 a.m. was found when comparing the years 1979 and 1980 (P less than 0.05). At the same time, the services of the outpatient department were claimed to a greater extent in the evening and night time in 1980 than prior to the introduction of CEST. Since the sample must be considered comparably as to age and sex distribution as well as calendar days and climatic influence, and change in routine due to the adaptation to daylight saving time is discussed as the most probable reason for the observed increase in accidents. The influence of CEST apparently exceeds a short adjustment phase. Further studies are recommended to investigate a possible correlation between daylight saving time and an increased risk of accidents.

Accidents↗
PubMed1988

Time perspective, time attitude, and time orientation in alcoholism: a review.

It has been proposed that alcoholics may have a disrupted subjective sense of time. A review of empirical investigations of alcoholics' psychological time functioning is presented, attempting to carefully distinguish between the concepts of time perspective, time attitude, and time orientation. It is recognized that the label "alcoholic" is not a homogeneous diagnosis, and it is used here for individuals in treatment for problems related to alcohol abuse. Important questions raised by the previous investigations are listed along with speculations about the role of cognitive impairment in relation to time functioning of alcoholics. Suggestions are made for potential differential treatment according to the patients' time functioning as it relates to motivation, and for additional research needed in this area.

Alcoholism↗
PubMed1989

A reassessment of the bleeding time: association of age, hematocrit, platelet function, von Willebrand factor, and bleeding time thromboxane B2 with the length of the bleeding time.

In order to provide an overview of the relative contribution of platelet, von Willebrand factor, and other abnormalities to patients with clinical bleeding difficulties, we performed a retrospective survey of coagulation studies on 569 individuals referred to the University of Manitoba coagulation laboratory because they, or a closely related family member, showed clinical evidence of a bleeding disorder. There was a highly significant (p less than 0.001) negative correlation between the bleeding time and each of the following parameters: the platelet count; the hematocrit; the percent aggregation to collagen, epinephrine, ADP, and arachidonic acid; and the logarithm of von Willebrand factor antigen and a measure of its activity (ristocetin cofactor). A significant and independent inverse relationship between the length of the bleeding time and the extent of platelet adhesion to glass beads, patient age, and prothrombin consumption were also observed. Multivariate analysis of the ability of all parameters to predict the bleeding time showed an r2 of only 0.33. Bleeding time thromboxane B2, in a second smaller study of 70 patients, showed a negative correlation with the length of the bleeding time (p = 0.0001), and, when used together with the above parameters, significantly enhanced the ability to predict the length of the bleeding time (r2 = 0.55). Defects in platelet function, as measured in vitro, and significant enough to have an effect on the bleeding time, occurred with greater frequency than defects in von Willebrand factor in the Manitoba patients evaluated.

Adolescent↗