Surgical stress impairment of murine natural killer cell cytotoxicity involves pre- and postbinding events

NK cell cytotoxicity may provide an important first line of defense against the implantation of circulating tumor emboli. Previously we reported that murine hind limb amputation induces a rapid and marked impairment of perioperative NK cell cytotoxicity that is associated with increased metastatic activity compared to unmanipulated tumor-bearing controls. Because tumor emboli are systemically discharged in patients undergoing solid tumor resection, we thought it pertinent to begin examining the mechanism underlying the perioperative impairment of murine NK cell cytotoxicity. Studies presented in this report suggest that the mechanism of impairment is multifactorial and includes the surgical stress-induced expansion of splenic erythroblasts that successfully compete with NK cells for YAC-1 target binding sites. In addition, although there is no surgically mediated decrease in splenic NK cell content (as defined morphologically, phenotypically, and functionally), there is an acute decrease in maximal NK cell recycling capacity. An accurate understanding of the mechanisms mediating perioperative impairment of NK cell cytotoxicity may be important in the future development of NK-specific perioperative immunomodulation strategies.     

Semi-quantitative estimation of changes in noradrenaline content and intraneuronal distribution in the rat vas deferens by fluorescence histochemistry

Summary A semi-quantitative histochemical assay for noradrenaline was developed, based on the assumption that the rate of reaction of noradrenaline with paraformaldehyde depends on transmitter concentration. Changes in organ noradrenaline content caused by drugs or cold-stress were associated with similar changes in fluorescence intensity of organ samples taken for microscopy. Differences in the fluorescence intensity of experimental and control tissues were also found when there was no change in total noradrenaline content, suggesting that fluorescence intensity is not a simple function of whole organ noradrenaline content. Changes in the relative fluorescence of experimental tissues with different paraformaldehyde exposures suggested that the intraneuronal distribution of noradrenaline may affect the rate of development of fluorescence. Analysis of the time course of the fluorescence reaction showed that this was best described by the sum of two first-order exponential components of different half-life. Further results suggested that the first, fast component represents vesicle-bound noradrenaline, while the slow component represents extragranular transmitter.     

The Massachusetts school‐based body mass index experiment—gleaning implementation lessons for future childhood obesity reduction efforts

In 2009, Massachusetts (MA) Department of Public Health (DPH) implemented new regulations that required public schools in the state to measure height and weight, determine body mass index (BMI), and notify parents of children in grades 1, 4, 7, and 10 of their child's weight status. After 3 years of implementation, MA DPH recently abandoned parental notification of school‐based BMI screening results citing several concerns including flaws in the ability to monitor the way that the BMI screening results were communicated from the schools to parents/guardians and some reports of breaches in confidentiality of students' measurements. In this article, we review implementation issues that could have impacted the success of the MA DPH regulation as well as lessons to be learned and potentially applied to future childhood obesity efforts.     

Effect of Lincocin Treatment on the Greening Process in Bean (Phaseolus vulgaris) Leaves

The effect of lincocin (a plastid protein synthesis inhibitor) treatment on the greening process of bean (Phaseolus vulgaris L.) leaves have been studied. In comparison with control leaves treated ones had a decreased rate of chloroplast development. They had a marked chlorophyll deficiency and a decreased chlorophyll a/b ratio. Some long and short wavelength forms of chlorophyll a were lacking as evidenced from the absorption spectra at 25°C and the fluorescence spectra at 77°K. The –¹⁴CO₂ fixation was inhibited by 80–90% in treated leaves. The fluorescence induced by the measuring light was greater in the treated leaves than in the control ones, and the kinetics of the decline of the relative fluorescence intensity were also different. Electron microscopic studies showed macrogranum-like structures and incomplete membrane vesicles in the treated plastids. After longer treatment a destruction of membranes was observed. The results indicate some structural and functional membrane deficiencies and instability of the membranes.     

Rats' memory for event duration: differential effects of delaying the discriminative choice cue as opposed to the opportunity to execute the choice response

Rats were trained to discriminate short or long durations of houselight illumination using a choice procedure. During the test phase of each trial, the left and right levers were presented with an auditory cue above one of them on (cued lever) while the other was off (uncued lever). The auditory cue was presented immediately after sample offset and the levers were inserted after the auditory cue had been presented for 2 s. For half of the rats, the correct response following the short sample was to press the cued lever, while following the long sample, it was to press the uncued lever. This was reversed for the remaining rats. Following acquisition of the discrimination, two different types of delay tests were administered. In the first set, the delay between offset of the sample and onset of the auditory cue was manipulated (Cue Delay Test). In the second set, the delay between onset of the auditory cue and entry of the levers into the chamber was manipulated (Response Delay Test). Cue Delay testing resulted in a choose-long bias at the longer delays. Response Delay testing did not result in a systematic response bias and there was little forgetting over the delay interval. These data suggest that the rats did not stop the internal clock when the nominal sample was offset, but allowed it to keep running until the auditory cue was presented. The data from the Response Delay Test indicate that either a response decision was made based on the clock reading as soon as the auditory cue was presented, or the clock reading itself was retained over the delay with no subjective shortening and little forgetting.