Onset of spermatozoal degeneration in low-fertility Delaware roosters and test for autoimmune basis

The objectives of this study were 1) to determine the onset of a heritable reproductive disorder in the rooster that is characterized by extensive spermatozoal degeneration within the ductus deferens, and 2) to determine if autoimmunity was associated with spermatozoal degeneration. Seventy-five percent of the affected roosters did not ejaculate large percentages of degenerate spermatozoa at 20 wk of age, approximately the age of sexual maturity. Rather, seminal quality gradually declined over the next 6 wk, as both ejaculate volume and number of spermatozoa ejaculated increased. The evaluation of testicular and excurrent duct tissues via immunofluorescence failed to reveal either IgY or IgA associated with spermatozoa. While histological examination revealed greater lymphocyte numbers (P less than .05) in the proximal ductus deferens, these cells were not associated with spermatozoa nor spermatozoal clumping. While spermatozoal degeneration tends to be latent at the onset of semen production, it does not appear to be due to spermatozoal autoimmunity.     

High-resolution myocardial perfusion mapping in small animals in vivo by spin-labeling gradient-echo imaging.

An ECG and respiration-gated spin-labeling gradient-echo imaging technique is proposed for the quantitative and completely noninvasive measurement and mapping of myocardial perfusion in small animals in vivo. In contrast to snapshot FLASH imaging, the spatial resolution of the perfusion maps is not limited by the heart rate. A significant improvement in image quality is achieved by synchronizing the inversion pulse to the respiration movements of the animals, thereby allowing for spontaneous respiration. High-resolution myocardial perfusion maps (in-plane resolution=234 x 468 microm2) demonstrating the quality of the perfusion measurement were obtained at 4.7 T in a group of seven freely breathing Wistar-Kyoto rats under isoflurane anesthesia. The mean perfusion value (group average +/- SD) was 5.5 +/- 0.7 ml g(-1)min(-1). In four animals, myocardial perfusion was mapped and measured under cardiac dobutamine stress. Perfusion increased to 11.1 +/- 1.9 ml g(-1)min(-1). The proposed method is particularly useful for the study of small rodents at high fields.     

Measurement of oxygen uptake in the non-steady-state

The purpose of these experiments was to develop and validate an open-circuit technique for measurement of gas exchange during the transition from rest to constant load steady-state exercise. The design of the open-circuit system employed to measure gas exchange in these experiments used a mixing chamber to collect the subject's expired ventilation where fractions of O2 and CO2 were determined via electronic gas analyzers. A gasometer was used to measure inspired ventilation and the analog signals from the two gas analyzers and the gasometer were sent to a microcomputer for computation of VO2. In calculating VO2, the mixed expired gas concentrations were matched with ventilatory volume using a previously determined time delay. To determine the validity of the open-circuit system, four subjects performed a series of 16 rest-to-work transitions on a cycle ergometer. In eight of the experiments, serial measurements of VO2 were obtained every 20 s for 3 min using the open-circuit mixing chamber system while the additional eight experiments used the Douglas bag technique. No significant difference (p greater than 0.05) existed between VO2 values calculated by the two techniques. Mean differences in VO2 between the two techniques during the first three 20-s measurement periods were 6, 53, and 63 ml, respectively. Using the Douglas bag technique as the standard, this represents a relative measurement error of 0.1%, 4.5%, and 3.6%, respectively, at the above time intervals. These data demonstrate that an open-circuit system employing a mixing chamber and the appropriate time delay to match expired gas fractions and ventilation is a sensitive means of measurement of VO2 in the non-steady-state.     

Identification of Risk Factors for Postoperative Nausea and Vomiting in the Perianesthesia Adult Patient

Postoperative nausea and vomiting (PONV) is a common and potentially debilitating complication of surgery. The preoperative assessment of PONV using established risk assessment tools enables the identification of patients at risk and potentially decreases the incidence of PONV in adult surgical patients. The identification of risk factors associated with PONV and the factors that are independent predictors of PONV preoperatively can facilitate the effective prophylactic treatment and management of PONV in adult surgical patients.     

Computer-Assisted Detection of Pulmonary Nodules: Preliminary Observations Using a Prototype System with Multidetector-Row CT Data Sets

The continued revolution in multidetector-row CT (MDCT) scanning increases the quality of lung imaging but at the cost of a greater burden of data for review and interpretation. This article discusses our preliminary experience with prototype software for lung nodule detection and characterization using MDCT data sets. We discuss the potential role of computer-assisted detection (CAD) as applied to the automatic detection of lung nodules. We also review the process of CAD, outline its potential results, and explore how it may fit into existing radiology practice. Finally, we discuss MDCT data-acquisition parameters and how they may affect the performance of CAD.     

Operant Conditioning of Heart Rate: Somatic Correlates

The relationships between heart rate (HR) and several parameters of somatic activity were evaluated in human subjects when shuck avoidance was made contingent on either increases or decreases in HR. In order to depict any influence of the contingency specific 10 HR, somatic activity was controlled to varying degrees by instructions and the use of non-contingent control groups. When increases in HR were reinforced, the contingency we found to influence somatic activity but an effect specific to HR was also observed. When decreases in HR were reinforced, there was no evidence that HR were influenced independently of somatic activity. The result are discussed with respect to several current issues.