The effect of position on autonomic nervous activity in late pregnancy

We investigated the effect of three different recumbent positions on autonomic nervous activity in late pregnancy. Thirty pregnant and 24 nonpregnant aged-matched women were studied, and measures of heart rate variability in both time and frequency domains were compared using supine, right and left lateral decubitus positions. In the nonpregnant women, the normalised high-frequency power was greatest in the right lateral decubitus position. In the pregnant women, the normalised high-frequency power was lowest and the low/high-frequency power ratio was greatest in the supine position. Both the percentage decrease of normalised high-frequency power and the percentage increase of low/high-frequency power ratio in the supine and right lateral positions were greater than those in the left lateral position. For women in late pregnancy, the left lateral decubitus position may be beneficial because cardiac vagal activity is least suppressed and cardiac sympathetic activity is least enhanced. Aortocaval compression might be the mechanism underlying the change in cardiac autonomic nervous activity when supine and right lateral decubitus positions are assumed in late pregnancy.     

Computer-based image analysis of nucleoli in prostate carcinoma

The authors have evaluated the nucleoli in 37 cases of prostatic carcinoma. The increase in Gleason's grade 1 correlated with an increase in the percentage of nucleolated nuclei. The increase in the percentage of bi- and trinucleolated nuclei was accompanied by a decrease of the uninucleated nuclei. The values of morphometrical parameters studied in the individual nucleoli (area, perimeter, diameters) increased in Gleason grade 2 tumors as compared with grade 1 tumors. In tumors higher grades there was, however, a progressive decrease of these values.     

Biobased plastics with insect‐repellent functionality

Natural insecticides/repellents, such as pyrethrum (derived from chrysanthemum plants), and insect repellent N,N‐Diethyl‐meta‐toluamide (DEET) were added to poly(lactic acid) (PLA) fibers through extrusion and spray coating on the PLA fabrics. Contact irritancy assay (CIA) showed that DEET‐treated PLA fabrics caused the lowest relative escape response of mosquitoes with an escape frequency of 33.3% ± 3.3%, indicating that DEET was less effect compared with natural insecticides/repellents. This was followed by the extruded natural pyrethrum‐treated PLA fabric with an escape frequency of 80% ± 6.3%. Finally, the PLA fabrics spray‐coated with natural pyrethrum caused the highest escape frequency of 98.3% ± 1.7%. Thus, it was found that pyrethrum/PLA fabrics functioned as a mosquito repellent better than DEET/PLA fabrics. In addition, TGA and tensile testing results demonstrated that pyrethrum was sufficiently thermally stable to be extrusion compounded with PLA. GPC results showed that DEET promoted de‐polymerization of PLA when co‐extruded. The results demonstrated that pyrethrum can be a viable additive for PLA to produce fibers that function as mosquito repellent to produce temporary garments that are compostable. The potential use of the developed biobased fibers with natural insect repellents is for single use of personal protection equipment (PPE) garments. POLYM. ENG. SCI., 59:E460–E467, 2019. © 2019 Society of Plastics Engineers     

Monocular deprivation induces homosynaptic long-term depression in visual cortex

Brief monocular deprivation during early postnatal development can lead to a depression of synaptic transmission that renders visual cortical neurons unresponsive to subsequent visual stimulation through the deprived eye. The Bienenstock-Cooper-Munro (BCM) theory proposes that homosynaptic mechanisms of long-term depression (LTD) account for the deprivation effects. Homosynaptic depression, by definition, occurs only at active synapses. Thus, in contrast to the commonly held view that the synaptic depression caused by monocular deprivation is simply a result of retinal inactivity, this theoretical framework indicates that the synaptic depression may actually be driven by the residual activity in the visually deprived retina. Here we examine the validity of this idea by comparing the consequences of brief monocular deprivation by lid suture with those of monocular inactivation by intra-ocular treatment with tetrodotoxin. Lid suture leaves the retina spontaneously active, whereas tetrodotoxin eliminates all activity. In agreement with the BCM theory, our results show that monocular lid suture causes a significantly greater depression of deprived-eye responses in kitten visual cortex than does treatment with tetrodotoxin. These findings have important implications for mechanisms of experience-dependent plasticity in the neocortex.     

Discovery of L-755,507: a subnanomolar human beta 3 adrenergic receptor agonist

A study of 4-acylaminobenzenesulfonamides in a cloned human beta 3 adrenergic receptor assay resulted in the discovery of n-hexylurea, L-755,507 (22). This 0.43 nM beta 3 agonist, which is > 440-fold selective over both beta 1 and beta 2 binding, is among the most potent human beta 3 agonists reported to date.     

The pulsatile characteristics of hypothalamo-pituitary-adrenal activity in female Lewis and Fischer 344 rats and its relationship to differential stress responses

The dynamic patterns of basal and stimulated hypothalamo-pituitary-adrenal (HPA) activity of freely moving female Lewis and Fischer 344 rats were compared using an automated blood-sampling system. Both strains showed pulsatile corticosterone release throughout the 24 h cycle. Lewis rats showed clear circadian variation in both pulse frequency (8.4 +/- 0.4 pulses between 1700-2300 h vs. 5.3 +/- 0.8 pulses between 0500-1100 h; P < 0.05) and height (198 +/- 27 ng/ml between 1700-2300 h vs. 107 +/- 14 ng/ml between 0500-1100 h; P < 0.05). Fischer rats exhibited pulses of similar frequency and height to those in Lewis rats during the evening, but showed no circadian variation, resulting in higher mean daily corticosterone concentrations. Although both strains showed behavioral and HPA responses to white noise stress (10 min; 114 dB), Fischer rats showed much greater increases in total activity, grooming, and rearings, and two important differences in the corticosterone responses were observed. First, in Lewis rats a clear relationship existed between basal and stimulated HPA activities, in that a significant response was seen only when the stress coincided with the rising (secretory active) phase of a basal pulse. Noise stress coinciding with a falling (nonsecretory) phase elicited no significant response. In contrast, Fischer rats showed similar responses regardless of the underlying pulse phase. Second, after the peak response at 20 min (Lewis, 237 +/- 67 ng/ml; Fischer, 390 +/- 57 ng/ml), corticosterone levels fell rapidly in Lewis rats, but remained maximally elevated for 20 min in Fischer rats, resulting in a significantly greater integrated response. The corticosterone response to i.v. CRF was unaffected by pulse phase in both strains, suggesting that a suprapituitary mechanism mediates the phase-dependent response to stress in the Lewis strain. CRF-induced corticosterone levels rose more rapidly in Fischer rats, peaking at 10 min (473 +/- 95 ng/ml) compared with 30 min (390 +/- 75 ng/ml) in Lewis rats, suggesting greater pituitary sensitivity in this strain. Thus, differences in both central and pituitary control of the HPA axis contribute to the strain difference in stress responsiveness between female Lewis and Fischer rats.     

Contribution of psychosocial factors to socioeconomic differences in health

The National Survey of Mid-life Developments in the United States (MIDUS) is one of several studies that demonstrate socioeconomic gradients in mortality during midlife. When MIDUS findings on self-reported health, waist to hip ratio, and psychological well-being were analyzed for their possible roles in generating socioeconomic differences in health, they revealed clear educational gradients for women and men (i.e., higher education predicted better health). Certain potential mediating variables, like household income, parents' education, smoking behavior, and social relations contributed to an explanation of the socioeconomic gradient. In addition, two census-based measures, combined into an area poverty index, independently predicted ill health. The results suggest that a set of both early and current life circumstances cumulatively contribute toward explaining why people of lower socioeconomic status have worse health and lower psychological well-being.     

Atherogenic lipoproteins support assembly of the prothrombinase complex and thrombin generation: modulation by oxidation and vitamin E

OBJECTIVE: The aim of this study was to assess whether contractile response of arteries to aqueous component of cigarette smoke extract (CSE) may be modulated in atherosclerotic arteries. METHODS: Thoracic aortas were isolated from control rabbits and from 1.5% cholesterol-fed rabbits, all of which had visible advanced atheromatous surface changes on the aortas. CSE was prepared by bubbling main stream of smoke from one cigarette with filter into 2 ml of phosphate-buffered saline. The thoracic aortic rings were suspended in organ chambers and tested with CSE (0.01-3.0 microliters/ml buffer in the organ chamber) after precontraction with 0.1 mumol/l of phenylephrine (PE). RESULTS: The contractile response to CSE was significantly greater in atherosclerotic aortas than in control aortas (the maximal contraction expressed as % of the precontraction; control aortas 10.8 +/- 2.8%, atherosclerotic aortas 42.6 +/- 4.7%; P < 0.01). The magnitude of the precontractions by PE was not different between control and atherosclerotic aortas. Exogenous addition of superoxide dismutase (SOD) significantly attenuated the CSE-induced contraction in both control and atherosclerotic aortas and pretreatment of aortic rings with diethyldithiocarbamate to deplete of endogenous vascular CuZn-SOD activity potentiated the CSE-induced contraction in control aortas, while it had no significant effect in atherosclerotic aortas. The vascular SOD activity was significantly lower in atherosclerotic aortas than in control aortas ((U/mg protein): control aortas 38.2 +/- 3.3, atherosclerotic aortas 18.5 +/- 2.4; P < 0.01). CONCLUSION: These results indicate that atherosclerotic arteries may be supersensitive to the constrictor effect of superoxide anion derived from CSE. The decrease in endogenous vascular SOD activity may partly contribute to the increased susceptibility to oxidative stress in atherosclerotic arteries.     

Effect of systemic corticoid and antihistamine alone or in combination on elements of the response to a two dose nasal allergen challenge

Adenosine, an endogenous vasodilator, induces a cerebral vasodilation at hypotensive infusion rates in anaesthetized humans. At lower doses (< 100 micrograms kg-1 min-1), adenosine has shown to have an analgesic effect. This study was undertaken to investigate whether a low dose, causing tolerable symptoms of peripheral vasodilation affects the global cerebral blood flow (CBF). In nine healthy volunteers CBF measurements were made using axial magnetic resonance (MR) phase images of the internal carotid and vertebral arteries at the level of C2-3. Quantitative assessment of CBF was also obtained with positron emission tomography (PET) technique, using intravenous bolus [15O]butanol as tracer in four of the subject at another occasion. During normoventilation (5.4 +/- 0.2 kPa, mean +/- s.e.m.), the cerebral blood flow measured by magnetic resonance imaging technique, as the sum of the flows in both carotid and vertebral arteries, was 863 +/- 66 mL min-1, equivalent to about 64 +/- 5 mL 100 g-1 min-1. The cerebral blood flow measured by positron emission tomography technique, was 59 +/- 4 mL 100 g-1 min-1. All subjects had a normal CO2 reactivity. When adenosine was infused (84 +/- 7 micrograms kg-1 min-1.) the cerebral blood flow, measured by magnetic resonance imaging was 60 +/- 5 mL 100 g-1 min-1. The end tidal CO2 level was slightly lower (0.2 +/- 0.1 kPa) during adenosine infusion than during normoventilation. In the subgroup there was no difference in cerebral blood flow as measured by magnetic resonance imaging or positron emission tomography. In conclusion, adenosine infusion at tolerable doses in healthy volunteers does not affect global cerebral blood flow in unanaesthetized humans.     

Intracellular K+ suppresses the activation of apoptosis in lymphocytes

Little is known about the mechanisms of suppression of apoptosis. We have addressed the novel possibility that the level of intracellular K+ regulates the apoptotic process by controlling the activity of death enzymes. We show that K+, at normal intracellular levels, inhibits both apoptotic DNA fragmentation and caspase-3(CPP32)-like protease activation, suggesting that intracellular K+ loss must occur early during apoptosis. Direct measurement of K+ by inductively coupled plasma/mass spectrometry and flow cytometry indicates a major decrease in intracellular K+ concentration in the apoptotic cell. Flow cytometric analysis revealed that caspase and nuclease activity were restricted to the subpopulation of cells with reduced K+. Disruption of the natural K+ electrochemical gradient suppressed the activity of both caspase and nuclease independent of the mode of activation of the apoptotic inducing agent, demonstrating that a decrease in intracellular K+ concentration is a necessary, early event in programmed cell death.