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Biomedical subjects

A Beker

Publications and source records attributed to A Beker.

6 recordsLinked to original sources
PubMed2003

Graded atmospheric oxygen level effects on performance and ascites incidence in broilers.

The effects of graded atmospheric O2 concentration (12, 14, 16, 18, and 20.6%) on chick performance and propensity to develop ascites were investigated using commercial male broilers. Chicks were housed in calorimetry chambers for 2 wk with incoming air diluted with N to provide the desired O2 concentration at thermoneutral (TN) ambient temperature. Day 14 body weight, weight gain, feed consumption, and gain-to-feed ratio increased (P < 0.01) as O2 concentration incrementally rose from 12 to 20.6%. Body weight was 138 g for the lowest atmospheric O2 level compared to 371 g for 20.6% O2. The greatest treatment difference occurred between the 12 and 14% O2 concentrations. Growth depression appeared related to feed consumption. Ascites heart ratio (AHR), ascites score (AS), right ventricular mass (RVM), and hematocrit (HCT) all increased (P < 0.01) as O2 concentration decreased. Blood HCT appeared to be a more sensitive indicator of physiological change attributable to atmospheric O2 than AHR, AS, or RVM. The data reported herein suggests that 19.6% atmospheric O2 is the minimal allowable level for housing birds within a relatively stress-free, TN environment to avoid cardiac and HCT changes related to ascites.

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PubMed1996

Analysis of high frequency QRS potential during exercise testing in patients with coronary artery disease and in healthy subjects.

High resolution ECG waveforms from leads V3, V4, V5, and V6 were analyzed in two groups of male subjects before, during, and following treadmill exercise testing. Group A included 32 coronary artery disease (CAD) patients, with arteriographically proven > 75% obstruction of at least two main coronary arteries, and group B included 30 healthy subjects, without history or symptoms of CAD. Signal averaging and filtering techniques were used in order to enhance the signal-to-noise ratio of the recorded ECG. The averaged QRS waveforms were filtered between 150 and 250 Hz. QRS complexes of the four leads were combined to form a "precordial average complex" (PAC). The PAC signals were examined for each subject at different stages of the exercise test and two parameters were computed: the root mean square (RMS) voltage; and the peak amplitude. The values of RMS and peak amplitudes measured at each stage of the exercise test were normalized to the values at rest. Normalized RMS (NRMS) values at peak exercise, immediately after peak exercise, and during the recovery phase were found to be higher for the healthy subjects than for the CAD group (1.17 +/- 0.31 vs 0.94 +/- 0.26, P < 0.008 at peak exercise, 1.13 +/- 0.24 vs 0.84 +/- 0.19, P < 0.001 after peak exercise, 1.08 +/- 0.22 vs 0.94 +/- 0.17, P < 0.007 during recovery). Cut-off NRMS value of one had a sensitivity of 81.3% and a specificity of 70.0% in differentiating CAD patients from healthy subjects in the examined groups. Normalized peak amplitude (NAMP) values exhibited similar behavior, with higher values for the healthy subjects than for the CAD group (1.23 +/- 0.48 vs 0.94 +/- 0.36, P < 0.03 at peak exercise, 1.20 +/- 0.34 vs 0.83 +/- 0.28, P < 0.001 after peak exercise, 1.10 +/- 0.29 vs 0.94 +/- 0.23, P < 0.02 during recovery). Specificity of 73.3% and sensitivity of 71.8% were found using a postpeak NAMP cut-off value of 1. In conclusion, the present study shows that using high frequency ECG may contribute to identifying patients with CAD. Further studies in larger groups of patients are required to better define the true predictive value of the method described for the diagnosis of CAD.

Adult↗
PubMed1995

Bronchodilator, oxygen level, and temperature effects on ascites incidence in broiler chickens.

Oxygen level, ambient temperature, and bronchodilator (metaproterenol) effects on performance, ascites incidence, and hematology were investigated using commercial broilers. In Experiment 1, two atmospheric oxygen concentrations (17.6, 20.6%) and two ambient temperatures (26.7, 32.2 C) were examined in a factorial arrangement. The low-oxygen (17.6%), ambient temperature combination (26.7 C) reduced (P < .01) weight gain whereas the high-oxygen ambient temperature combination enhanced (P < .05) such performance. Ascites incidence for chicks housed at 32.2 C was higher (P < .01) for birds maintained at 17.6% oxygen but oxygen concentration did not impact ascites incidence at 26.7 C. White blood cell counts were elevated in the low-oxygen (17.6%) group at both 26.7 and 32.2 C, and hematocrit was positively (R = .84; P < .05) correlated with ascites incidence. In Experiment 2, two oxygen levels (17.6, 20.6%) at constant 26.7 C were examined with and without metaproterenol, a bronchodilator. Metaproterenol reduced (P < .01) ascites incidence at 17.6% oxygen and completely prevented ascites at 20.6% oxygen. The data suggest that therapeutic development may be enhanced by using hematocrit as an indices of ascites and further that studies directed at bronchodilation have potential to alleviate ascites.

Animals↗
PubMed1989

An improved detection algorithm in fetal electrocardiography.

Fetal electrocardiogram signals from abdominal recordings were digitized and processed by a personal computer. An averaged maternal signal was derived from the cross-correlation function and nonrecursive digital filtering. The cross-correlation function was calculated from the cross-spectrum and the fast Fourier transform algorithm. The maximum value of the cross-correlation function and the time location of that value were found by (1) searching for the similarity between the waveforms (for elimination of artifacts) and (2) measuring the relative time delay (for the waveform's alignment in the averaging process) between the ECG waveforms. Prior to this procedure each of the ECG waveforms was filtered through a nonrecursive digital high-pass filter. With this procedure a template signal corresponding to one complete maternal ECG signal is obtained. The fetal ECG and the electromyogram (EMG) are suppressed in the maternal template waveform, since they are not correlated with the maternal ECG. The averaged maternal ECG was then subtracted from the abdominal signals. The subtraction results in complete elimination of the maternal signal, thus it is possible to detect all of the fetal QRS complexes in spite of their coincidence with the maternal ECG. An averaged fetal ECG is then extracted using the same averaging process to improve the signal-to-noise ratio, making it possible to recognize fetal P and T waves. The performance of this method was assessed using simulated and recorded (real) abdominal ECG signals. This method shows a significant improvement with respect to detection of fetal heart rate, evaluation of short-term variation in the heart rate, and detection of arrhthymia disturbances in the fetal ECG.(ABSTRACT TRUNCATED AT 250 WORDS)

Algorithms↗
PubMedDate not supplied

Effect of oxygen level on ascites incidence and performance in broiler chicks.

An experiment was conducted using male Cobb x Cobb broiler chicks to evaluate the effect of two oxygen levels on the incidence of ascites, performance, and blood chemistry. Ascites occurred in the 13.6% oxygen groups on the fifth day of the experiment. Body weights and survivability were significantly lower (P < 0.05) in chicks maintained at the low oxygen level than in controls (20.6% oxygen). Hematocrits were significantly higher only in chicks with ascites at the 13.6% oxygen level. Hemoglobin was significantly higher (P < 0.05) in chicks with ascites at 13.6% oxygen than in chickens at 20.6% oxygen. Lactate dehydrogenase values were significantly higher in non-ascitic chicks maintained at 13.6% oxygen and in chicks with ascites at 20.6% oxygen than in non-ascitic chicks 20.6% oxygen.

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