Age and Histamine metabolism

The age carve of histamine in the rat skin exhibits a general, fairly constant level of 10 to 20 microg./g. ap to 500 days. 'I'here are, however, two exceptions, the peak about birth and the peak about weaning. Between these two disturbances values not much above the normal adult figures are obtained. The rise at weaning has been shown to be separable into two parts. Observations on the histamine content of bread and milk (less than 0.5 microg./g.) and of rat cake (about 5 microg./g.) show that these cannot account for the steady rise observed between 16 and 24 days. This may be due to alterations in the intestinal flora on changing from a milk diet to solid food or to hormonal imbalance. These causes probably account, in large measure, for the other irregularities noted in the literature at about this age. Changes in epidermal thickness and tissue fat content may influence the change but are not of prime importance.The peak observed at 22 days in large but not in small litters is ascribed to the shock of premature weaning. Not weaning . a large litter eliminated this peak and the suggestion is further supported by weaning a small litter prematurely and by the results obtained after traumatic stress. These results indicate that the increase in skin histamine after such treatment may be caused by a relative hypocortism.Apart from this theoretical aspect the results reported here indicate that careful consideration should he given to weaning schedules to ensure that all litters are, as far as possible, similar. The practice of some authors of allowing the litter to remain with the mother till thirty days has much to recommend it.The rise before birth may again be related to changes in the thyroid and adrenal glands and forms part of the general metabolic changes at parturition.An important point arising from Section 4. is that shin not affected directly by the stressing agent did show a change in histamine content. The use of unaffected areas as simultaneous controls i should clearly be used with caution.It would appear that, in general, changes in the histamine content of the skin indicate a disturbance! of the hormonal balance of the adrenal and thyroid. These changes may also be an indicator of disturbed protein metabolism (133, 134). The gerontological importance of such disturbances has been pointed out in the Introduction, and theory suggests that work on successive stresses might be informative. The results indicate that animals about 50 days old might show differences in their skin histamine reactions which could be related to their previous experience; Such differences do not appear to exist in adult (330 day) animals

Duo-check valve, 2-inch mission valve and Pump Company part number 15BVFCC1C, NASA DRAWING number 75Mo4406 PCV-2 Test report

Testing and evaluation of 2-inch duo-check valve for Saturn IB progra

Fish assemblage patterns as a tool to aid conservation in the Olifants River catchment (East), South Africa

South Africa has committed to address freshwater conservation at the catchment scale, using a combination of landscapelevel and species-level features as surrogates of freshwater biodiversity. To support this work, we examined fishes in the Olifants River catchment, where multiple anthropogenic pressures affect streams. Patterns in fish assemblage data across 88 sites were analysed and related to landscape environmental variables using statistical techniques of multivariate ordination, cluster analysis, and regression tree analysis. We identified 6 distinct fish assemblage types, which were separated by altitude and human influence, primarily dry-land cropping and dams. In the upper reaches of the catchment, we identified a faunal shift from Barbus neefi, which occurred in less impacted sites, to B. anoplus and Tilapia sparrmanii, which werefavored in cropland and mixed cropland/urban settings, respectively. The fish assemblage of the middle section of the catchment was not unique, but supported one species, Chiloglanis pretoriae, that could be considered a focal species for conservation. The low altitude, high-runoff section of the catchment supported the most species. However, species richnessincreased in association with dams, through the addition of species that are more tolerant of flow and physicochemical modifications. Thus, species richness may not be an optimal conservation target for this system. Rather, a series of indicators will be necessary to track and measure conservation success in the Olifants catchment

Scapular and humeral movement patterns of people with stroke during range-of-motion exercises

BACKGROUND AND PURPOSE: Range-of-motion (ROM) exercises may contribute to hemiparetic shoulder pain, but the underlying mechanisms are unknown. This study examined scapular and humeral movement patterns in people with hemiparesis post stroke as they performed commonly prescribed ROM exercises. METHODS: Using kinematic techniques, we studied 13 people with hemiparesis, both with and without pain, as they performed three commonly prescribed ROM exercises: person-assisted ROM, self-assisted ROM, and cane-assisted ROM. Their data were compared to a group of 12 matched control subjects performing scapular plane shoulder elevation using mixed model ANOVAs. Correlation analyses were used to examine the relationship between participants’ ratings of pain and kinematic data. RESULTS: The hemiparetic group had mild pain at rest that increased during the performance of the exercises. During shoulder elevation, humeral external rotation in the hemiparetic group was decreased in all three ROM exercises compared to the control group. Scapular upward rotation in the hemiparetic group was decreased for the person-assisted ROM exercise only. No differences in scapular tilt were found between groups. The extent of movement abnormalities was not related to pain severity. DISCUSSION AND CONCLUSIONS: People with hemiparesis had altered scapular and humeral movement patterns and increased shoulder pain when performing the ROM exercises. These data can assist clinicians in making decisions regarding which exercises to prescribe to preserve shoulder motion and prevent contractures in this population

Multi-site phosphorylation controls the neurogenic and myogenic activity of E47.

The superfamily of basic-Helix-Loop-Helix (bHLH) transcription factors influence cell fate in all three embryonic germ layers, and the tissue-specific class II factors have received prominent attention for their potent ability to direct differentiation during development and in cellular reprogramming. The activity of many class II bHLH proteins driving differentiation, and the inhibitory class VI bHLH factor Hes1, is controlled by phosphorylation on multiple sites by Cyclin-dependent kinases (Cdks). As class II proteins are generally thought to be active through hetero-dimerisation with the ubiquitously expressed class I E proteins, regulation of class I transcription factors such as E47 may influence the activity of multiple tissue-specific bHLH proteins. Using differentiation of nerve and muscle in Xenopus frog embryos as a model system, we set out to explore whether with the ubiquitously expressed class I E protein E47 that hetero-dimerises with Class II bHLHs to control their activity, is also regulated by multi-site phosphorylation. We demonstrate that E47 can be readily phosphorylated by Cdks on multiple sites in vitro, while ectopically-expressed E47 exists in multiple phosphorylated forms in Xenopus embryos. Preventing multi-site phosphorylation using a phospho-mutant version of E47 enhances the neurogenic and myogenic activity of three different class II bHLH reprogramming factors, and also when E47 acts in hetero-dimerisation with endogenous proteins. Mechanistically, unlike phospho-regulation of class II bHLH factors, we find that preventing phosphorylation of E47 increases the amount of chromatin-bound E47 protein but without affecting its overall protein stability. Thus, multi-site phosphorylation is a conserved regulatory mechanism across the bHLH superfamily that can be manipulated to enhance cellular differentiation.This work was supported by Medical Research Council Research Grants MR/L021129/1 and MR/K018329 and AP receives core funding from Wellcome and MRC at the Wellcome-MRC Cambridge Stem Cell Institute. LH is supported by a Peterhouse Research Fellowship

Model-free and model-based reward prediction errors in EEG

Learning theorists posit two reinforcement learning systems: model-free and model-based. Model-based learning incorporates knowledge about structure and contingencies in the world to assign candidate actions with an expected value. Model-free learning is ignorant of the world’s structure; instead, actions hold a value based on prior reinforcement, with this value updated by expectancy violation in the form of a reward prediction error. Because they use such different learning mechanisms, it has been previously assumed that model-based and model-free learning are computationally dissociated in the brain. However, recent fMRI evidence suggests that the brain may compute reward prediction errors to both model-free and model-based estimates of value, signalling the possibility that these systems interact. Because of its poor temporal resolution, fMRI risks confounding reward prediction errors with other feedback-related neural activity. In the present study, EEG was used to show the presence of both model-based and model-free reward prediction errors and their place in a temporal sequence of events including state prediction errors and action value updates. This demonstration of model-based prediction errors questions a long-held assumption that model-free and model-based learning are dissociated in the brain

Comment on "A centrosome-independent role for gamma-TuRC proteins in the spindle assembly checkpoint"

Müller et al. (Reports, 27 October 2006, p. 654) showed that inhibition of the γ-tubulin ring complex (γ-TuRC) activates the spindle assembly checkpoint (SAC), which led them to suggest that γ-TuRC proteins play molecular roles in SAC activation. Because γ-TuRC inhibition leads to pleiotropic spindle defects, which are well known to activate kinetochore-derived checkpoint signaling, we believe that this conclusion is premature

Linked Fate: Justice and the Criminal Legal System During the COVID-19 Pandemic

The concept of “linked fate” has taken on new meaning in the face of the COVID-19 pandemic. People all over the world – from every walk of life, spanning class, race, gender, and nationality – face a potentially deadly threat requiring cooperation and sacrifice. The plight of the most vulnerable among us affects the capacity of the larger community to cope with, recover, and learn from COVID-19’s devastating impact. COVID-19 makes visible and urgent the need to embrace our linked fate, “develop a sense of commonality and shared circumstances,” and unstick dysfunctional and inequitable political and legal systems. Nowhere is the hazard of failing to recognize linked fate more urgent than in the criminal legal system. COVID-19 pandemic has hit people who live and work in correctional institutions particularly hard. The government bears legal and moral responsibility for people incarcerated in prisons, jails, and juvenile detention facilities, who cannot leave and must depend for their survival of the pandemic on the state. The movement in and out of correctional facilities by those employed to fulfill government’s responsibility also ensures the spread of infection. One study, for example, found that increases in a county\u27s jail incarceration rate were associated with significant rates of infectious disease deaths. The collective failure to attend to the circumstances that enmesh people in the criminal legal system – poverty, racial discrimination, poor health and mental care health care – also make prisons and jails a ground zero of the pandemic\u27s spread

Demonstration of dynamic thermal compensation for parametric instability suppression in Advanced LIGO

Advanced LIGO and other ground-based interferometric gravitational-wave detectors use high laser power to minimize shot noise and suspended optics to reduce seismic noise coupling. This can result in an opto-mechanical coupling which can become unstable and saturate the interferometer control systems. The severity of these parametric instabilities scales with circulating laser power and first hindered LIGO operations in 2014. Static thermal tuning and active electrostatic damping have previously been used to control parametric instabilities at lower powers but are insufficient as power is increased. Here we report the first demonstration of dynamic thermal compensation to avoid parametric instability in an Advanced LIGO detector. Annular ring heaters that compensate central heating are used to tune the optical mode away from multiple problematic mirror resonance frequencies. We develop a single-cavity approximation model to simulate the optical beat note frequency during the central heating and ring heating transient. An experiment of dynamic ring heater tuning at the LIGO Livingston detector was carried out at 170 kW circulating power and, in agreement with our model, the third order optical beat note is controlled to avoid instability of the 15 and 15.5 kHz mechanical modes. We project that dynamic thermal compensation with ring heater input conditioning can be used in parallel with acoustic mode dampers to control the optical mode transient and avoid parametric instability of these modes up to Advanced LIGO\u27s design circulating power of 750 kW. The experiment also demonstrates the use of three mode interaction monitoring as a sensor of the cavity geometry, used to maintain theg-factor product tog(1)g(2)= 0.829 +/- 0.004