Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Time”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources
PubMed2002

Usefulness of analytical CEA doubling time and half-life time for overlooked synchronous metastases in colorectal carcinoma.

BACKGROUND: Measurement of carcinoembryonic antigen (CEA) has been widely applied to detect recurrence, especially of colorectal carcinoma. The validity however, is still controversial. We investigated serial changes in CEA values to calculate whether the CEA doubling time and half-life time could predict metastatic progression or prognosis in colorectal carcinoma. METHODS: Pre- and post-operative serial serum CEA contents were determined in 22 cases of colorectal cancer with or without metastasis. CEA values were determined by enzyme immunoassay (EIA). Patients were assigned depending upon survival time (within vs. more than 18 months after primary resection) for assessment of CEA doubling time. From the gradient of the semi-logarithmic CEA graph, the preoperative doubling time was calculated and the postoperative half-life time was estimated according to the diagnosis of metastases within 2 years after primary resection [metastasis (+) or (-)]. RESULTS: In spite of the effect of curative re-operation of metastatic lesions or of postoperative adjuvant chemotherapy, the CEA doubling time of the groups showed a relation with prognosis (p = 0.045, Student's t-test) when the patients were divided into >18 and < or =18 months survival time. The CEA half-life time of the groups without overlooked metastases was statistically longer than those with (mean +/- SD 8.01 +/- 2.07 and 4.33 +/- 1.11, respectively, p < 0.01, one-factor ANOVA test). Clearance (k) showed a significant difference between the groups (p < 0.001, Student's t-test). CONCLUSION: The CEA doubling time appeared to be a less independent prognostic factor, whereas prolongation of the CEA half-life time might potentially suggest the existence of overlooked synchronous metastases from colorectal carcinoma.

Adrenal Gland Neoplasms↗
PubMed2004

Spectral Fraunhofer regime: time-to-frequency conversion by the action of a single time lens on an optical pulse.

We analyze a new regime in the interaction between an optical pulse and a time lens (spectral Fraunhofer regime), where the input pulse amplitude is mapped from the time domain into the frequency domain (time-to-frequency conversion). Here we derive in detail the conditions for achieving time-to-frequency conversion with a single time lens (i.e., for entering the spectral Fraunhofer regime) as well as the expressions governing this operation. Our theoretical findings are demonstrated both numerically and experimentally. A comparative study between the proposed single-time-lens configuration and the conventional dispersion + time-lens configuration for time-to-frequency conversion is also conducted. Time-to-frequency conversion with a single time lens can be used for applications similar to those previously proposed for the conventional time-to-frequency converters, e.g., high-resolution measurement of fast optical temporal waveforms. Moreover, our results also indicate that the spectral Fraunhofer regime provides additional capabilities for controlling and processing optical pulses.

Journal Article↗
PubMed1990

Momentary time sampling as an estimate of percentage time: A field validation.

This study examined the percentage time estimates of momentary time sampling against the real time obtained with handheld computers in a natural setting. Twenty-two concurrent observations were conducted in elementary schools by one observer who used 15-s momentary time sampling and a second who used a handheld computer. Results for the six behaviors showed a close correspondence between the momentary time sampling percentage observation intervals and the real time percentage observation time, although 15-s momentary time sampling tended not to sample low-frequency short-duration behaviors. The results confirmed laboratory findings that short-interval momentary time sampling estimates percentage time accurately for a wide range of behavior frequencies and durations, and suggested that observers using momentary time sampling in a natural setting are able to obtain accurate data.

Journal Article↗
PubMed1990

Derivation of flow-volume and time domain spirometric indices by digitisation of volume-time spirograms.

All the information regarding the forced expiratory manoeuvre are contained in the simple volume-time spirogram. Flow-volume and time-domain indices could be derived by digitising the volume-time spirogram. This paper describes an electronic means of digitising the spirogram and demonstrates its capability in deriving flow-volume and time-domain spirometric indices. The spirograms of 118 granite quarry workers were digitised using an electronic digitising pen. The volume and time data are stored in a micro-computer and a programme written in dBASEIII Plus is used to smoothen and derive the standard volume-time, flow-volume and time domain indices. There was good agreement between digitised and hand-read values (intraclass correlation coefficients, rI, greater than 0.9) for the forced expiratory flow in one second (FEV1) and forced vital capacity (FVC) irrespective of the pulmonary status. There was a small but statistically significant difference between digitised and hand-read FEV1 for those with normal and restrictive pulmonary function groups (-115 ml/sec and 19 ml/sec respectively). There was however, no evidence of systematic bias between the two methods. The technique described herein provides a rapid and accurate means for deriving flow-volume and time domain indices from a volume-time spirogram. It also provides the opportunity to reanalyse previously collected volume-time spirograms and allow for the assessment of small airways function of these subjects using newer flow-volume and time domain indices.

Forced Expiratory Volume↗
PubMed2001

From physical time to the first and second moments of psychological time.

After examination of the status of time in experimental psychology and a review of related major texts, 2 opposite approaches are presented in which time is either unified or fragmented. Unified time perception views, usually guided by Weber's law, are embodied in various models. After a brief review of old models and a description of the major contemporary models of time perception, views on fragmented time perception are presented as challenges for any unified time view. Fragmentation of psychological time emerges from (a) disruptions of the Weber function, which are caused by the types of interval presentation, by extensive practice, and by counting explicitly or not; and (b) modulations of time sensitivity and perceived duration by attention and interval structures. Weber's law is a useful guide for studying psychological time, but it is also reasonable to assume that more than one so-called central timekeeper could contribute to perceiving time.

Attention↗
PubMed1994

Influence of sampling time on assessment of potential doubling time.

Potential doubling time (Tpot), S-phase transit time (Ts), and labeling index were determined in three experimental rodent tumors by in vivo incorporation of bromodeoxyuridine and flow cytometry. The kinetic parameters were derived from the relative movement method at varying sampling times (time between injection of bromodeoxyuridine and tumor excision). Ts and Tpot were close to the expected (extrapolated) values of the two parameters with sampling time within the range 60-100% of the expected Ts. With short sampling time, Ts and Tpot were considerably over- or underestimated. By use of the original method by (Begg et al., Cytometry 6:620-626, 1985), the Tpot came out with a twofold overestimation with a short sampling time. Generally, modified methods for calculation of Ts did not improve the results. When Tpot is measured in human tumors, there is no a priori knowledge of the kinetic parameters. Consequently, the sampling time must be based on the general experience of tumor cell kinetics in the specific tumor type measured. A relatively long sampling time should be aimed for when measuring Tpot in human tumors. With proper sampling time, Tpot assessed by flow cytometry was found to be a precise and reproducible parameter.

Adenocarcinoma↗
PubMed1983

Physiological time and time-invariance.

An operational definition of physiological time is suggested that involves a non-linear transformation of a physical time-scale such that a certain temperature-dependent process becomes time-invariant. The definition expresses that physiological time has the dimension of time, and can be measured in units such as days or weeks. It is shown that the quantification of a physiological time-scale requires the specification of an arbitrary constant, which equals the rate of change of the process in physiological time. When the process-rate also depends on some internal variable, the interaction of this variable with temperature must be multiplicative, if a single physiological time-scale is to be used. The relationship with conventional uses of physiological time is discussed. The time-scale, as defined here, reduces to degree-day summation or development accumulation if certain multiplicative constants are deleted.

Animals↗
PubMed1995

Carcinoma of the uterine cervix. I. Impact of prolongation of overall treatment time and timing of brachytherapy on outcome of radiation therapy.

PURPOSE: Some studies have described decreased pelvic tumor control and survival rates in invasive carcinoma of uterine cervix when the overall time in a course of definitive irradiation is prolonged. We attempt to confirm or deny these observations and evaluate the impact of timing of brachytherapy on outcome. We also explore the hypothesis that more extensive tumors technically require prolongation of the course of irradiation; thus, decreased tumor control and survival in these patients may not necessarily be the result of time/dose factor. METHODS AND MATERIALS: Records of 1,224 patients (Stage IB to III) treated with definitive irradiation (combination of external beam and two intracavitary insertions to deliver doses of 70 to 90 Gy to point A) were reviewed. Follow-up was obtained in 97% of the patients (median, 12 years; minimum, 3 years; maximum, 28 years). The relationship between outcome and overall treatment time and time of intracavitary insertions was analyzed in each stage and according to tumor size/extent. RESULTS: There was strong correlation between overall treatment time (OTT) and tumor stage (< or = 7 weeks: 81% for Stage IB; 74% for Stage IIA; 52% for Stage IIB; and 47% for Stage III). Interruptions of therapy accounting for prolongation of treatment time occurred in 25-30% of patients, most frequently because of holidays and weekends and side effects of therapy. Overall treatment time had a major impact on pelvic tumor control in Stages IB, IIA, and IIB; in Stage IB 10-year actuarial pelvic failure rates were 7% with OTT < or = 7 weeks, 22% with 7.1 to 9 weeks, and 36% with > 9 weeks (p < or = 0.01). For Stage IIA the corresponding values were 14%, 27%, and 36% (p = 0.08), and in Stage IIB pelvic failure rates were 20%, 28%, and 34%, respectively (p = 0.09). In Stage III, pelvic failure was 30%, 40%, and 50%, respectively (p = 0.08). There was also a strong correlation between OTT and 10-year cause-specific survival (CSS); in Stage IB rates were 86% with OTT of < or = 7 weeks, 78% for 7.1 to 9 weeks, and 55% for > or = 9 weeks (p < 0.01). The corresponding rates in Stage IIA were 73%, 41%, and 48% (p < or = 0.01). For patients with Stage IIB, CSS rates were 72% for OTT < or = 7 weeks, 60% for 7.1 to 9 weeks, and 70% for > 9 weeks (p = 0.01). Patients with Stage III disease had 45% 10-year CSS when treatment was delivered in 9 weeks or less and 36% for longer overall times (p = 0.16). In multivariate analysis of patients with Stage IB and IIA, OTT and clinical stage were the most important prognostic factors for pelvic tumor control, disease-free survival, and CSS. Tumor size was a prognostic factor for CSS. In Stages IIB and III, OTT, clinical stage, unilateral or bilateral parametrial invasion, and dose to point A were significant prognostic factors for pelvic tumor control, disease-free survival, and CSS. Prolongation of time had a significant impact on pelvic tumor control and CSS regardless of tumor size, except in Stage IB tumors < or = 3 cm. Regression analysis confirms previous reports that prolongation of OTT results in decreased pelvic tumor control rate of 0.85% per day for all patients, 0.37% per day in Stages IB and IIA, 0.68% per day in Stage IIB, and 0.54% for Stage III patients treated with > or = 85 Gy to point A. Performance of all intracavitary insertions within 4.5 weeks from initiation of irradiation yielded decreased pelvic failure rates in some groups of patients (8.8 vs. 18% in Stage IB and IIA tumors < or = 4 cm and 12.3 vs. 35% in Stage IIB) (p < or = 0.01). CONCLUSIONS: Prolongation of treatment time in patients with Stage IB, IIA, IIB, and III carcinoma of the uterine cervix has a significant impact on pelvic tumor control and CSS. The effect of OTT was present regardless of tumor size except in Stage IB tumors < or = 3 cm.

Actuarial Analysis↗
PubMed2005

Quantifying the combined effects of the heating time, the temperature and the recovery medium pH on the regrowth lag time of Bacillus cereus spores after a heat treatment.

The purpose of this study was to quantify the lag time of re-growth of heated spores of Bacillus cereus as a function of the conditions of the heat treatment: temperature, duration and pH of the recovery medium. For a given heating temperature, curves plotting lag times versus time of heating show more or less complex patterns. However, under a heating time corresponding to a decrease of 2 decimal logarithms of the surviving populations of spores, a linear relationship between the lag time of growth and the time of the previous heat treatment can be observed. The slope of this linear relationship followed itself a Bigelow type linear relationship, the slope of which yielded a zeta-value very close to the observed conventional z-value. It was then concluded that the slope of the regrowth lag time versus the heating time followed a linear relationship with the sterilisation value reached in the course of the previous heat treatment. A sharp effect of the pH of the medium which could be described by a simple "secondary" model was observed. As expected, the observed intercept of the linear relationship between lag time and heating time (lag without previous heating) was dependent on only the pH of the medium and not on the heating temperature.

Adaptation, Physiological↗
PubMedDate not supplied

Sumatriptan and lost productivity time: a time series analysis of diary data.

Two previously conducted clinical studies assessed lost nonworkplace activity time and lost workplace productivity time due to migraine symptoms in subjects using sumatriptan for 6 months to treat their migraines after a 12- to 18-week period of using their usual therapy without sumatriptan. Although statistically significant differences in lost nonworkplace activity time and lost workplace productivity time between the usual therapy and sumatriptan treatment periods were detected using the Wilcoxon signed-rank test, this test could not determine whether differences were attributable to inherent trends in the data. This current study employed time series analysis, which detects and controls for preexisting trends in data, to further explore the possibility that the observed reductions in lost time in the two clinical studies were related to management of the subjects with sumatriptan. The intercepts and slopes of the computed linear models suggest that the initiation of sumatriptan therapy produced savings of 0.8 hours of nonworkplace activity time and 0.5 hours of workplace productivity time per patient per week. These savings were sustained throughout the sumatriptan treatment period. Preexisting trends in the data were not detected in the models. Thus the productivity gains are not associated with either time effects or the statistical phenomenon of regression to the mean, but variables that are extreme in initial measurements will tend to be closer to the center of the distribution in subsequent measurements. This strengthens the hypothesis that management of migraine with sumatriptan is associated with reductions in lost productivity time.

Activities of Daily Living↗
PubMed1999

Time factors in larynx tumor radiotherapy: lag times and intertumor heterogeneity in clinical datasets from four centers.

PURPOSE: To use the time-dependent linear-quadratic model, both in the standard form and in a form modified to incorporate intertumor heterogeneity, in a reanalysis of 4 datasets for larynx tumor control, to provide more representative and direct estimates of the lag period, the time factor (lambda/alpha), and the clonogen population inactivation dose ([lnk]/alpha). METHODS AND MATERIALS: The data comprised 2,225 patients treated in Edinburgh (UK), Glasgow (UK), Manchester (UK), or Toronto (Canada), with tumor control assessed after at least 2 years. Heterogeneity in each series was taken into account using the coefficient of variation (CV) of the clonogen radiosensitivity (alpha). Maximum likelihood techniques were used to provide best estimates of the parameters, and also direct estimation of the more stable parameter ratios of interest. RESULTS: The use of different heterogeneity factors for the different series allowed common dose/time parameters to be fitted across all four series in a way not possible using the standard model, enabling the inherent effect of heterogeneity in flattening dose-response curves and in reducing time factors to be separated from the underlying more-representative values. Radiosensitivity CVs were calculated to be 30% (Edinburgh), 36% (Glasgow), 40% (Manchester), and 71% (Toronto). The lag phase was 32 days (95% CL 20-38 days) which was longer than the value of 23 days (11-36 days) deduced using the standard model without the heterogeneity parameter. The time factor was 1.2 (0.8-2.2) Gy/day, again greater than the value of 0.80 (0.54-1.41) Gy/day derived using the standard model. Similar larger time factors and longer lag periods could be reproduced using the standard model either by using a parameterization based on parameter ratios, or by omitting the discordant Toronto data and refitting just the data from the three UK centers. CONCLUSION: It was concluded that the heterogeneity model provides a better representation of the time factor for tumor control when data are analyzed comprising different stages of disease treated at different centers. The model allows different amounts of heterogeneity in different series, which tend to flatten dose-responses curves and reduce time factors, to be taken in to account. Also, direct maximum likelihood estimates can be made of the lag period, the time factor (lambda/alpha), and the fractionation sensitivity (beta/alpha), as well as the clonogen population inactivation dose (lnk)/alpha. Values of these parameter ratios are more robust and stable than the individual parameter values. The results of the present analysis using a total of 2,225 patients from four centers indicate that the average lag period may be somewhat longer and the average time factor somewhat greater (and the 95% confidence limits of the time factor exclude previous estimates), than the values deduced previously using simpler models and more diverse multi-center datasets.

Dose-Response Relationship, Radiation↗
PubMed2005

The effect of feeding time on shell quality and oviposition time in broiler breeders.

Three experiments were performed to determine the effect of feeding time on shell quality and oviposition time in broiler breeders. Mean eggshell thickness was increased significantly by 3.5 microm (approximately 1%) per h delay in feeding time when hens were housed in individual cages. However, eggshell thickness was not significantly affected by feeding time when birds were housed on litter floors. Mean oviposition time was delayed relative to lights on by 5 min per h delay in feeding time. Egg weight was not significantly affected by feeding time, suggesting that differences in shell thickness and oviposition times were not due to increased oviducal transit times. Producers who wish to implement delayed feeding may have to turn lights on earlier than usual to compensate for delayed oviposition times.

Animal Feed↗
PubMed2004

Effect of time of castration and tumour volume on time to androgen-independent recurrence in Shionogi tumours.

OBJECTIVE: To use the androgen-dependent Shionogi tumour model in mice to help define the effects of the timing of androgen ablation on the development of androgen resistance in prostate cancer, as the timing of androgen ablation remains controversial. MATERIALS AND METHODS: Groups of nine mice were castrated at 1, 3, 6, 10 and 14 days after tumour inoculation, with a similar-sized group of mice castrated before tumour inoculation serving as a control. The time of first palpable tumour recurrence and tumour volume was monitored after castration. RESULTS: All mice were observed for > or = 80 days after castration. Only mice castrated at 10 and 14 days had palpable tumour at the time of castration. Mice castrated at 14 days had the highest rate of early tumour recurrence (all nine) while mice castrated before inoculation or at 1 and 3 days afterward had a significantly lower rate of tumour recurrence (four of nine; P < 0.01). Mice castrated at 14 and 10 days had tumour recurrence significantly earlier than mice in the other groups. When calcium-channel blockers were administered to inhibit apoptosis, all mice had a similar time to recurrence and time to death regardless of the time of castration. CONCLUSIONS: Large tumour volume and corresponding delay in castration reduced the time to androgen-independent tumour recurrence and survival. Earlier androgen ablation, at the time of subclinical (impalpable) disease, significantly delayed the rate and time to androgen-independent recurrence compared with delayed therapy when the tumour burden was high.

Androgens↗
PubMed1989

Deficits in reaction times and movement times as correlates of hypokinesia in monkeys with MPTP-induced striatal dopamine depletion.

1. We quantitatively assessed deficits in the initiation and execution of arm movements occurring after destruction of nigrostriatal dopamine neurons by systemic administration of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) (Sigma). Three monkeys performed a reaction time task in which they reached toward a single and constant target for food reward. 2. After administration of MPTP, all three monkeys showed hypokinesia necessitating dopamine precursor or receptor agonist treatment. The partial recovery of one animal from initial akinesia after 19 days permitted discontinuation of dopaminergic drug therapy, although marked hypokinesia remained present. The two other animals displayed additional, intermittent phases of rigidity and activation tremor and needed continuous dopaminergic drug therapy for most of the postlesion period. 3. Administration of MPTP significantly prolonged EMG reaction time in prime mover muscles and arm movement reaction time by 47-225% and 18-129%, respectively, on the six sides of the three animals, compared with control measurements before the lesion. EMG and arm movement reaction time increased over consecutive trials in most sessions comprising 110-130 movements, the first 20 movements showing almost normal values. The delay time between onsets of EMG and arm movement showed unsystematic changes. These deficits in movement initiation were observed both with and without dopamine precursor therapy. They lasted during the whole testing period of several months. 4. Linear correlations between arm movement onset and EMG onset in the two prime mover muscles, the extensor digitorum communis and the biceps, showed coefficients of mostly 0.7-0.9, both before and after MPTP. These data suggest that the temporal relationship between onsets of arm movement and EMG were not substantially affected by MPTP. 5. Arm movement time was divided into two phases. The duration of movement between the resting key and the target, a small food-containing box located ahead of the animal, was denoted as reaching movement time. The following hand manipulation inside the food box was measured as box movement time. After MPTP, both measures were significantly prolonged by 10-103% and 12-251%, respectively, on the six sides of the three monkeys. These deficits in movement execution were observed both with and without dopaminergic drug therapy and during the whole testing period. 6. Task performance after MPTP treatment was studied in one monkey in the absence of dopaminergic drug therapy. EMG and arm movement reaction times recovered partially over several weeks, while the prolongations in reaching and box movement times remained unchanged.(ABSTRACT TRUNCATED AT 400 WORDS)

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed2005

Real-time objective assessment of knot quality with a portable tensiometer is superior to execution time for assessment of laparoscopic knot-tying performance.

OBJECTIVE: Laparoscopic intracorporeal knot tying is a difficult skill to acquire. Currently, time to complete a knot is the most commonly used metric to assess the acquisition of this skill; however, without a measure of knot quality, time is a poor indicator of skills mastery. Others have shown that knot quality can be accurately assessed with a tensiometer, but obtaining this type of assessment has typically been cumbersome. We investigated a new method of real-time assessment of knot quality that allows for more practical use of knot quality as a performance metric. METHODS: Eleven experienced endoscopic surgeons tied 100 intracorporeal knots in a standard box trainer. Each of the knots was immediately tested using the InSpec 2200 benchtop tensiometer (INSTRON, Canton MA) where a knot quality score (KQS) is generated based on the load handling properties of the knotted suture. The execution time was also recorded for each knot. RESULTS: The assessment of all knots ended with one of two end points: knots that slipped (n=48) or knots that held until the suture broke (n=52). Knots that slip are generally of poorer quality than those that held. Execution time did not correlate with knot-quality score (r=0.009, P=.9), and the mean execution time did not differ significantly between slipped and held knots (65 vs 68 seconds, P=.8). No completion time criteria were able to accurately predict slipped versus held knots. The mean KQS difference between held and slipped knots was highly significant (24 vs 12, P<.0001). A knot with a KQS exceeding 20 was nearly 10 times more likely to hold than slip. CONCLUSION: Time to complete a knot is a poor metric for the objective assessment of intracorporeal knot-tying performance in the absence of a measure of knot quality. Real-time evaluation of the knot quality can accurately distinguish well-tied knots from poorly tied knots. This mode of assessment should be incorporated into training curriculum for surgical knot tying.

Biomechanical Phenomena↗
PubMed1997

Simple reaction times and timing of serial reactions of middle-aged and old men.

The timing control of serial reactions in 20 middle-aged (38-43 years) and 20 older men (57-63 years) was examined by using a task of tracking serial-light stimuli with and without the previous learning (Exps. III and II, respectively). In Exp. I, a control group of 20 college students (19-22 years) had significantly faster and less variable mean simple reaction times than the two other groups. For the serial reaction times (Exps. II and III), the control group had significantly faster mean reaction times than the other groups who did not differ. In Exp. III, there was no difference between the serial reaction times and the simple reaction times in the contrasting groups. In Exp. II, however, although the serial reaction times were significantly slower than the simple reaction times in the older group, the serial reaction times did not differ from the simple reaction times in the middle-aged group. The difference between these groups appeared to be due to the task in Exp. II being more difficult than that in Exp. III, suggesting the more complex the movement to be made, the slower the responses of older people. Advancing age seems to have a greater effect on central processing components than on the perceptual and motor output components of serial reactions.

Age Factors↗
PubMed1997

[Study on the best sampling time and the time distribution of atmospheric bacterial particle].

The changes of atmospheric bacterial particle concentrations in three areas--Beijing, Tianjin and Shenyang, were investigated in different seasons and period of one day. The samplers used in this study were MF-45 and HTK-201 air microbial samplers. The results showed that the concentrations of atmospheric bacterial particle in Beijing and Tianjin are higher in spring than those in other seasons. They are 2053/m3 and 2556/m3 respectively in spring, 995/m3 and 1064/m3 respectively in summer. The concentrations of atmospheric bacterial particle in Shenyang is higher in autumn (10108/m3) and lower in winter (1294/m3). The changes of atmospheric bacterial particle concentrations have two peak values during a day. The two high peak values are at 6:00 to 7:00 and 18:00, while the two low values are at 11:00 to 13:00 and 1:00 to 2:00. We sampled the atmospheric bacterial particles at 4 different combinations of sampling time in the three cities. They were 12, 8, 6 and 4 times a day. The sampling time combination was analyzed by mathematical statistics according to the results. The best sampling time was decided by the statistics results and time distribution character of atmospheric bacterial particle concentration in different seasons and period of one day. The concentration of atmospheric bacterial particle should be detected in the middle month of the four seasons: January, April, July and October. Sampling time at 7:00, 10:00, 13:00, 16:00, 19:00, 22:00, 1:00 and 4:00 could be selected for 8 times sampling a day. The sampling time sequence should be at 5:00, 11:00, 17:00 and 23:00 for 4 times sampling a day. The four times sampling at daytime in spring and fall should be at 6:00, 9:00, 12:00 and 19:00; 5:00, 9:00, 13:00 and 17:00 in summer; 7:00, 10:00, 13:00 and 16:00 in winter.

Air Microbiology↗
PubMed1990

Prediction of vitamin K response using the Echis time and Echis-prothrombin time ratio.

Echis carinatus venom contains proteases capable of activating both normal and descarboxy prothrombin. We showed this venom (Sigma) principally activates prothrombin with almost no factor X activation. Echis time in combination with prothrombin time can predict vitamin K responsiveness since the Echis time is usually normal in the presence of descarboxy prothrombin associated with vitamin K deficiency. 38 patients with abnormal routine prothrombin times (PT) had both coagulant and immunogenic factor II assays along with Echis times done before and after vitamin K. Of 22 patients responding to vitamin K, based on correction of PT, 21 had normal initial Echis times and of 16 not responding, 11 had abnormal Echis times, giving a sensitivity of 95.4% and specificity of 68.8% for vitamin K responsiveness. 90% of patients with a PT/Echis time ratio less than 1.3 and a prolonged Echis time did not correct their PTs with vitamin K therapy. The 5 non-responders with normal Echis times all showed normal initial coagulant and antigenic prothrombin, but 3 had low F V and/or F VII.

Blood Coagulation Disorders↗