Pituitary–adrenal responses to arm versus leg exercise in untrained man

The purpose of this study was to examine pituitary–adrenal (PA) hormone responses [beta-endorphin (β-END), adrenocorticotropic hormone (ACTH) and cortisol] to arm exercise (AE) and leg exercise (LE) at 60 and 80% of the muscle-group specific VO₂ peak. Eight healthy untrained men (AE VO₂ peak=32.4±3.0 ml kg⁻¹ min⁻¹, LE VO₂ peak=46.9±5.3 ml kg⁻¹ min⁻¹) performed two sub-maximal AE and LE tests in random order. Plasma β-END, ACTH and cortisol were not different (P>0.05) between AE and LE at either exercise intensity; the 60% testing elicited no changes from pre-exercise (PRE) values. For 80% testing, plasma β-END, ACTH and cortisol were consistently, but not significantly, greater during LE than AE. In general, plasma β-END and ACTH were higher (P<0.05) during 80% exercise, than PRE, for both AE and LE. Plasma cortisol was elevated (P<0.05) above PRE during 80% LE, and following 80% for both AE and LE. Plasma ACTH was higher (P<0.05) during 80% LE and AE versus 60% LE and AE, respectively. Plasma β-END and cortisol were significantly higher during and immediately after 80% LE than 60% LE. Thus, plasma β-END, ACTH and cortisol responses were similar for AE and LE at the two relative exercise intensities, with the intensity threshold occurring somewhere between 60 and 80% of VO₂ peak. It appears that the smaller muscle mass associated with AE was sufficient to stimulate these PA axis hormones in a manner similar to LE, despite the higher metabolic stress (i.e., plasma La^-) associated with LE.     

Time and Spatial Invariance of Impedance Signals in Limbs of Healthy Subjects by Time–Frequency Analysis

The bioelectric impedance technique is a non-invasive method that provides the analysis of blood volume changes in the arteries. This is made possible by an interpretation of the impedance signal variations. In this paper, time and spatial variations of such impedance signals are studied on recordings made on limbs of 15 healthy subjects at rest. For that purpose, the scalogram of each signal has been computed and quantitative measures based on energies were determined. The results show that the signals are statistically time invariant on three anatomical segments of the limbs: pelvis, thigh and calf. p Value varies between 0.20 and 0.52 for the absolute energies computed on scalograms of signals recorded at 5 min intervals. Moreover, the analysis made on the two legs of each subject shows that the signals are spatial invariant on the three anatomical segments. p Value varies between 0.0785 and 1.000 for the absolute energies computed on the scalograms of signals recorded simultaneously on the two legs. These conclusions will therefore help the clinicians in studying the temporal variations of physiological parameters on limbs with the impedance technique. Moreover, the results on the spatial invariance make possible the comparisons of these parameters with those given by other acquisition techniques.     

Quantitative SARS-CoV-2 anti-spike responses to Pfizer–BioNTech and Oxford–AstraZeneca vaccines by previous infection status

ObjectivesWe investigated determinants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) anti-spike IgG responses in healthcare workers (HCWs) following one or two doses of Pfizer–BioNTech or Oxford–AstraZeneca vaccines.MethodsHCWs participating in regular SARS-CoV-2 PCR and antibody testing were invited for serological testing prior to first and second vaccination, and 4 weeks post-vaccination if receiving a 12-week dosing interval. Quantitative post-vaccination anti-spike antibody responses were measured using the Abbott SARS-CoV-2 IgG II Quant assay (detection threshold: ≥50 AU/mL). We used multivariable logistic regression to identify predictors of seropositivity and generalized additive models to track antibody responses over time.Results3570/3610 HCWs (98.9%) were seropositive >14 days post first vaccination and prior to second vaccination: 2706/2720 (99.5%) were seropositive after the Pfizer–BioNTech and 864/890 (97.1%) following the Oxford–AstraZeneca vaccines. Previously infected and younger HCWs were more likely to test seropositive post first vaccination, with no evidence of differences by sex or ethnicity. All 470 HCWs tested >14 days after the second vaccination were seropositive. Quantitative antibody responses were higher after previous infection: median (IQR) >21 days post first Pfizer–BioNTech 14 604 (7644–22 291) AU/mL versus 1028 (564–1985) AU/mL without prior infection (p < 0.001). Oxford–AstraZeneca vaccine recipients had lower readings post first dose than Pfizer–BioNTech recipients, with and without previous infection, 10 095 (5354–17 096) and 435 (203–962) AU/mL respectively (both p < 0.001 versus Pfizer–BioNTech). Antibody responses >21 days post second Pfizer vaccination in those not previously infected, 10 058 (6408–15 582) AU/mL, were similar to those after prior infection followed by one vaccine dose.ConclusionsSARS-CoV-2 vaccination leads to detectable anti-spike antibodies in nearly all adult HCWs. Whether differences in response impact vaccine efficacy needs further study.     

Vertical eye position responses to steady-state sinusoidal fore–aft head translation in monkeys

A major function of the otolith organ is to detect linear acceleration generated by two different head conditions, dynamic linear translation and static tilt relative to gravity. To investigate these sensory functions of the otolith organ, we analyzed vertical eye position in response to steady-state sinusoidal fore–aft translation over a range of frequencies (0.5–4 Hz) and amplitudes (0.10–0.33 g) in three monkeys. Vertical vestibuloocular reflexes elicited by linear acceleration (LVORs) during sinusoidal fore–aft translation were divided into translational LVOR component and tilt LVOR component taking vertical gaze-dependent properties into account. Based on geometrical considerations, the translational LVOR component, but not the tilt LVOR component, depended on vertical gaze eccentricity. To quantify these two components, we used a V-shaped function model, plotting vertical eye sensitivities (deg/cm) against vertical gaze eccentricities (deg). The slope (deg/cm per degree) and intercept (sensitivity at zero gaze eccentricity) of this function approximately reflected the translational and tilt LVOR components, respectively. Our data show that the tilt LVOR component is independent of the reciprocal of the fixation distance (MA), whereas the translational LVOR component is almost linearly related to MA. The gain of the tilt LVOR component, characterized by low-pass dynamics, was greatest (0.36) at 0.5 Hz. Visual information clearly reduced the gain of the tilt LVOR component, by approximately 50%. There was no difference between the effects of large-field and small-spot stimuli. These findings demonstrate that steady-state sinusoidal fore–aft translation at lower frequencies stimulates the otolith organs and produces a pseudo-pitch tilt in cooperation with the gravito-inertial force and as a result elicits an ocular response equivalent to the tilt LVOR.     

High frequency of copy number imbalances in Rubinstein–Taybi patients negative to CREBBP mutational analysis

Rubinstein–Taybi syndrome (RSTS) is a rare autosomal dominant disorder characterised by facial dysmorphisms, growth and psychomotor development delay, and skeletal defects. The known genetic causes are point mutations or deletions of the CREBBP (50–60%) and EP300 (5%) genes. To detect chromosomal rearrangements indicating novel positional candidate RSTS genes, we used a-CGH to study 26 patients fulfilling the diagnostic criteria for RSTS who were negative at fluorescence in situ hybridisation analyses of the CREBBP and EP300 regions, and direct sequencing analyses of the CREBBP gene. We found seven imbalances (27%): four de novo and three inherited rearrangements not reported among the copy number variants. A de novo 7p21.1 deletion of 500 kb included the TWIST1 gene, a suggested candidate for RSTS that is responsible for the Saethre–Chotzen syndrome, an entity that enters in differential diagnosis with RSTS. A similar issue of differential diagnosis was raised by a large 4.3 Mb 2q22.3q23.1 deletion encompassing ZEB2, the gene responsible for the Mowat–Wilson syndrome, whose signs may overlap with RSTS. Positional candidate genes could not be sought in the remaining pathogenetic imbalances, because of the size of the involved region (a 9 Mb 2q24.3q31.1 deletion) and/or the relative paucity of suitable genes (a 5 Mb 3p13p12.3 duplication). One of the inherited rearrangements, the 17q11.2 379Kb duplication, represents the reciprocal event of the deletion underlying an overgrowth syndrome, both being mediated by the NF1-REP-P1 and REP-P2 sub-duplicons. The contribution of this and the other detected CNVs to the clinical RSTS phenotype is difficult to assess.     

Defects in acute responses to TLR4 in Btk-deficient mice result in impaired dendritic cell-induced IFN-γ production by natural killer cells

This study defines a critical role for Btk in regulating TLR4-induced crosstalk between antigen presenting cells (APCs) and natural killer (NK) cells. Reduced levels of IL-12, IL-18 and IFN-γ were observed in Btk-deficient mice and ex vivo generated macrophages and dendritic cells (DCs) following acute LPS administration, whilst enhanced IL-10 production was observed. In addition, upregulation of activation markers and antigen presentation molecules on APCs was also impaired in the absence of Btk. APCs, by virtue of their ability to produce IL-12 and IL-18, are strong inducers of NK-derived IFN-γ. Co-culture experiments demonstrate that Btk-deficient DCs were unable to drive wild-type or Btk-deficient NK cells to induce IFN-γ production, whereas these responses could be restored by exogenous administration of IL-12 and IL-18. Thus Btk is a critical regulator of APC-induced NK cell activation by virtue of its ability to regulate IL-12 and IL-18 production in response to acute LPS administration.     

Identification of Microorganisms by FilmArray and Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Prior to Positivity in the Blood Culture System

In this study, we investigated the performance of the FilmArray and matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) in identifying microorganisms from blood culture (BC) bottles prior to positivity. First, we used simulated BacT/Alert FA Plus BC bottles with five each for Escherichia coli and Staphylococcus aureus isolates. The FilmArray identified all 10 isolates before BC positivity with 9/10 at 5 h and 1 at 7.5 h after incubation in the BC system. MALDI-TOF MS failed to identify the isolates prior to positivity. When the bottles were incubated for 2.5 h at room temperature (RT) before we put them into the BC system, the FilmArray identified 6/10 at 2.5 h and the remaining 4 at 5 h. Finally, we tested simulated BC bottles after incubation at RT. Interestingly, 9/10 isolates were identified with the FilmArray after 8 h of incubation at RT. Second, we studied clinical BC bottles in quadruplicate. When three-fourths of the parallel bottles signaled positive, the FilmArray was run on the fourth nonsignaled bottle and was found to be positive in 14/15 such cases. Third, we analyzed the performance of the FilmArray in the identification of microorganisms from clinical BC bottles before incubation in the system. Two milliliters of broth from 400 BC bottles was collected after arrival at the laboratory and stored at −70°C. Sixteen bottles later signaled positive in the system. When the frozen broth from these bottles was analyzed, the FilmArray identified all the microorganisms in 8/16 bottles prior to incubation in the BC system. This study shows that the FilmArray can identify microorganisms from BC bottles prior to positivity and in some cases even prior to incubation in the BC system.     

Walk–run transition in young and older adults: with special reference to the cardio-respiratory responses

Cardio-respiratory responses of young and older subjects performing walking and running protocols at the walk–run transition speed (WRT) were compared. A total of 26 volunteers assigned to younger (YG, 24 ± 3 years) and older (OG, 64 ± 6 years) groups underwent a protocol to determine the WRT used in 6-min walking and running protocols. Oxygen uptake (VO₂), ventilation (V _E), expired carbon dioxide (VCO₂), heart rate (HR) and perceived exertion (RPE) were assessed. Oxygen pulse (O₂ pulse) and respiratory exchange ratio (RER) were calculated. The WRT was not different between groups (OG: 6.84 ± 0.69 km h⁻¹ vs. YG: 7.04 ± 0.77 km h⁻¹, P = 0.62). No between-group differences were found within a given gait pattern for VO₂ (P = 0.061) and VCO₂ (P = 0.076). However, VO₂ (P = 0.0022) and VCO₂ (P = 0.0041) increased in OG when running, remaining stable in YG (VO₂: P = 0.622; VCO₂: P = 0.412). The VE was higher in OG compared to YG in walking (P = 0.030) and running (P = 0.004) protocols. No age-related (P = 0.180) or locomotion (P = 0.407) effects were found for RER. The HR increased in OG and between-group difference was detected while running (P = 0.003). No within- (P = 0.447) or between-group (P = 0.851) difference was found for O₂ pulse. The net VO₂ increased from walking to running in OG (P < 0.0001) but not in YG (P = 0.53), while RPE was lower in YG (P = 0.041) but stable in OG (P = 0.654). In conclusion, the WRT speed was similar across the age groups. However, the VO₂ and VCO₂ increase from walking to running was larger for OG than YG. The HR, VE and RPE were also higher when running in OG compared to YG. Therefore, the locomotion strategy had different impacts on the metabolic demand of older and younger subjects.     

A few observations on linking VEP responses to the magno- and parvocellular systems by way of contrast–response functions

It has been proposed that magno- and parvocellular contributions to Visually Evoked Potentials (VEPs) can be isolated, or differentiated, by noting the contrast–response relationships of the responses. This suggestion is examined quantitatively by determining the similarity between various sets of VEP data that have been attributed to the magno- and parvocellular systems and previously reported contrast–response functions for different kinds of neurons (magno- and parvocellular neurons and V1, V4, and MT cells) and combinations of the contrast–response functions for these neurons. It is found that other neurons, or combinations of other neurons, typically give better fits to the data than do magno- and parvocellular cells. Thus, to attribute VEP responses to the magno- or parvocellular systems based on contrast–responses properties faces difficulties.     

Modification of rat thermal responses to morphine by α-FMH suggests a role for neural histamine in morphine tolerance

In rats, morphine may either raise or lower body temperature depending on the dose. A morphine dose of 50 mg/kg, i.p., consistently produced a nearly maximal hypothermic response in non tolerant rats, whereas this dosage induced an elevation of body temperature in tolerant rats. In rats pretreated with -fluoromethylhistidine (-FMH), an irreversible inhibitor of histidine decarboxylase which induces a reduction in brain histamine synthesis, this morphine dose of 50 mg/kg, i.p. produced an elevation of rectal temperature resembling that observed in morphine-tolerant rats. To confirm the suggestion that hyperthermic effects of the higher dose of morphine in morphine-tolerant rats or in -FMH-preteated rats could be related to a possible involvement of mediators of fever, e.g. prostaglandins, animals were pretreated with acetylsalicylic acid (aspirin, Bayer) 30 mg/kg, i.p., 60 min before morphine. Results showed that acetylsalicylic acid prevented the hyperthermic response of morphine, resulting in a fall in body temperature. Since morphine releases histamine and -FMH inhibits histamine synthesis, our data demonstrating that an inhibitor of prostaglandin-synthetase showed efficacy only in animals responding with fever to the higher dose of the opiate, suggests a physiological antagonism between histamine and prostaglandins on mechanisms underlying hyper/hypothermic responses to morphine.     

Regional characteristics of electrical responses (in the band 1–225 Hz) in the cerebral cortex to conditioned stimuli in operant conditioning

Power spectra of short-term (less than 1 sec) electrical responses to conditioned stimuli were studied over the frequency range 1–225 Hz in dogs during food-related operant conditioning. These spectra demonstrated regional characteristics in terms of energy levels and frequency composition. Responses were more marked in the visual and parietal areas of the left hemisphere. Power in responses to a differential stimulus were significantly lower than with responses to positive stimuli, mainly because of the high-frequency range (80–225 Hz); energy levels in these two situations were similar during prestimulus intervals. The frequency composition of responses was defined by a series of discrete frequencies in the gamma (30–80 Hz) and high-frequency ranges. __________ Translated from Zhurnal Vysshei Nervnoi Deyatel’nosti imeni I. P. Pavlova, Vol. 55, No. 5, pp. 658–670, September–October, 2005.     

Human EEG responses to 1–100 Hz flicker: resonance phenomena in visual cortex and their potential correlation to cognitive phenomena

The individual properties of visual objects, like form or color, are represented in different areas in our visual cortex. In order to perceive one coherent object, its features have to be bound together. This was found to be achieved in cat and monkey brains by temporal correlation of the firing rates of neurons which code the same object. This firing rate is predominantly observed in the gamma frequency range (approx. 30–80 Hz, mainly around 40 Hz). In addition, it has been shown in humans that stimuli which flicker at gamma frequencies are processed faster by our brains than when they flicker at different frequencies. These effects could be due to neural oscillators, which preferably oscillate at certain frequencies, so-called resonance frequencies. It is also known that neurons in visual cortex respond to flickering stimuli at the frequency of the flickering light. If neural oscillators exist with resonance frequencies, they should respond more strongly to stimulation with their resonance frequency. We performed an experiment, where ten human subjects were presented flickering light at frequencies from 1 to 100 Hz in 1-Hz steps. The event-related potentials exhibited steady-state oscillations at all frequencies up to at least 90 Hz. Interestingly, the steady-state potentials exhibited clear resonance phenomena around 10, 20, 40 and 80 Hz. This could be a potential neural basis for gamma oscillations in binding experiments. The pattern of results resembles that of multiunit activity and local field potentials in cat visual cortex. Electronic Publication     

Active versus passive transportation to school–differences in screen time,socio-economic position and perceived environmental characteristics in adolescent girls

Objective: The aims of this study were (1) to assess the relationships between transport to and from school (active vs. passive), sedentary behaviours, measures of socio-economic position and perceived environmental variables, and (2) to determine which, if any, variables were predictors of active transportation.

Methods: The sample comprised 705 girls with mean age of 14.7 (SD?=?1.6) years old. Questionnaires were used to describe travel mode to school and to estimate weekly television and computer use (screen time). Girls were assigned to active transportation (AT) or passive transportation (PT) groups depending on whether they walked or bicycled (AT) to and from school or travelled by car or bus (PT). Screen time was determined by the number of hours they reported watching television and using computers in the week preceding the examination, including weekends. Socio-economic position was established by parental occupation and educational level. A questionnaire assessed Perceived Neighbourhood Environments.

Results: No statistically significant differences were seen for screen time between travel groups. Occupational status of both mother (r?=??0.17) and father (r?=??0.15) and father's educational level (r?=??0.10) were significantly and negatively associated with AT, while street connectivity (r?=?0.10) was positively and significantly associated with AT. Logistic regression analysis showed that the likelihood of active commuting decreased by around 50% with increasing father's occupation (odds ratio (OR)?=?0.51; p?≤?0.05) and father's education (OR?=?0.52; p?≤?0.05) from low to middle socio-economic position groups. Further, the data showed that girls who agreed that ‘there are many four-way intersections in my neighbourhood’ were more likely to be active (OR?=?1.63; p?≤?0.05).

Conclusion: The data of this study showed that lower socio-economic position is associated with active commuting to school and that street connectivity is a predictor of active transportation in adolescent girls.     

A role for the heat shock protein–CD91 axis in the initiation of immune responses to tumors

For over 100 years, it has been established that tumor-specific immune responses can frequently be detected in the tumor-bearing host. Whether or not these immune responses are capable of controlling the growth of the tumor is influenced by many factors. However, the mechanism by which the immune responses are initiated in the first place has remained a dilemma. In this chapter, we present evidence that heat shock protein-peptide complexes released by tumor cells are the entity responsible for initiating the immune responses. Interaction of the extracellular HSP with its receptor CD91 is necessary for priming the immune response. We propose that the disruption of the HSP-CD91 interaction may be an active mechanism by which tumors prevent the generation of immune responses against it.     

Time trends in leisure time physical activity and physical fitness in the elderly: Five-year follow-up of the Spanish National Health Survey (2006–2011)

ObjectivesTo estimate the trends in the practice of leisure time physical activity, walking up 10 steps, and walking for 1 h, during the years 2006–2011, in elderly Spanish people.Study designObservational study, retrospective analysis of Spanish National Health Surveys. We analysed data collected from the Spanish National Health Surveys conducted in 2006 (n = 30,072) and 2011 (n = 21,007), through self-reported information. The number of subjects aged ≥65 years included in the current study was n = 5756 in 2006 (19.14%) and n = 4617 in 2011 (21.97%). We included responses from adults aged 65 years and older.Outcome measuresThe main variables included leisure-time physical activity, walking up 10 steps, and walking for 1 h. We analysed socio-demographic characteristics, individuals’ self-rated health status, lifestyle habits, co-morbid conditions and disability using multivariable logistic regression models.ResultsThe total number of subjects was 10,373 (6076 women, 4297 men). The probability of self-reported capacity was significantly higher in 2006 than in 2011 for leisure-time physical activity, walking up 10 steps, and walking for 1 h for both sexes (women: OR 2.20, 95%IC 1.91–5.55; OR 2.50, 95%IC 1.99–3.14; OR 1.04, 95%IC 1.01–1.07; men: OR 2.20, 95%IC 1.91–2.55; OR 2.01, 95%IC 1.40–2.89; OR 1.05, 95%IC 1.0–1.1) respectively. Both sexes were associated with a significantly lower probability of performing leisure-time physical activity, walking up 10 steps, and walking for 1 h. Additionally, those over 80 years of age, on average, showed a poor or very poor perception of their health and presented with some type of disability.ConclusionA decrease in the proportion of respondents who self-reported undertaking leisure-time physical activity, walking up 10 steps, and walking for 1 h was observed in the Spanish population of over 65 years between 2006 and 2011.     

Radiologists Help Each Other to Improve Efficiency by Decreasing the Time to Look Up a Patient’s Relevant Clinical History in the Electronic Medical Record

Journal of Digital Imaging - The study aims to prove that it takes less time to look up relevant clinical history from an electronic medical record (EMR) if the information is already provided in a...     

The IL-33/ST2 axis is crucial in type 2 airway responses induced by Staphylococcus aureus–derived serine protease–like protein D

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