Murine virus susceptibility of cell cultures of mouse, rat, hamster, monkey, and human origin.

Studies were initiated to determine the practicality of using various tissue cultures for the propagation of murine viruses isolated from laboratory animals. The cytopathogenic effects of 10 murine viruses known to cause disease in laboratory rodents were compared in monolayer cultures of L929, BHK-21, WI-38, BSC-1, and Vero cells. The susceptibility of primary hamster embryo, hamster kidney, mouse embryo, mouse kidney, and rat embryo cell cultures was also tested. Seven of the viruses produced effects in at least 1 of the cell substrates. The remaining 3 viruses, namely H-1, K, and mouse hepatitis, produced no effects in the cell cultures tested.     

Chemical Characteristics of Particulate, Colloidal, and Dissolved Organic Material in Loch Vale Watershed, Rocky Mountain National Park

The chemical relationships among particulate and colloidal organicmaterial and dissolved fulvic acid were examined in an alpine andsubalpine lake and two streams in Loch Vale Watershed, Rocky MountainNational Park. The alpine lake, Sky Pond, had the lowest dissolved organiccarbon (DOC) (0.37 mgC/L), the highest particulate carbon (POC) (0.13mgC/L), and high algal biomass. The watershed of Sky Pond is primarilytalus slope, and DOC and POC may be autochthonous. Both Andrews Creekand Icy Brook gain DOC as they flow through wet sedge meadows. Thesubalpine lake, The Loch, receives additional organic material from thesurrounding forest and had a higher DOC (0.66 mgC/L). Elemental analysis,stable carbon isotopic compositon, and ¹³C-NMR characterizationshowed that: 1) particulate material had relatively high inorganic contentsand was heterogeneous in compositon, 2) colloidal material was primarilycarbohydrate material with a low inorganic content at all sites; and 3)dissolved fulvic acid varied in compositon among sites. The lowconcentration and carbohydrate-rich character of the colloidal materialsuggests that this fraction is labile to microbial degradation and may beturning over more rapidly than particulate fractions or dissolved fulvic acid.Fulvic acid from Andrews Creek had the lowest N content and aromaticity,whereas Sky Pond fulvic acid had a higher N content and lower aromaticitythan fulvic acid from The Loch. The UV-visible spectra of the fulvic acidsdemonstrate that variation in characteristics with sources of organic carboncan explain to some extent the observed non-linear relationship betweenUV-B extinction coefficients and DOC concentrations in lakes.     

Moving toward a generalizable application of central thalamic deep brain stimulation for support of forebrain arousal regulation in the severely injured brain

This review considers the challenges ahead for developing a generalizable strategy for the use of central thalamic deep brain stimulation (CT/DBS) to support arousal regulation mechanisms in the severely injured brain. Historical efforts to apply CT/DBS to patients with severe brain injuries and a proof-of-concept result from a single-subject study are discussed. Circuit and cellular mechanisms underlying the recovery of consciousness are considered for their relevance to the application of CT/DBS, to improve consciousness and cognition in nonprogressive brain injuries. Finally, directions for development, and testing of generalizable criteria for CT/DBS are suggested, which aim to identify neuronal substrates and behavioral profiles that may optimally benefit from support of arousal regulation mechanisms.     

Evolutionary history of the SARS-CoV-2 Gamma variant of concern (P.1): a perfect storm

Our goal was to describe in more detail the evolutionary history of Gamma and two derived lineages (P.1.1 and P.1.2), which are part of the arms race that SARS-CoV-2 wages with its host. A total of 4,977 sequences of the Gamma strain of SARS-CoV-2 from Brazil were analyzed. We detected 194 sites under positive selection in 12 genes/ORFs: Spike, N, M, E, ORF1a, ORF1b, ORF3, ORF6, ORF7a, ORF7b, ORF8, and ORF10. Some diagnostic sites for Gamma lacked a signature of positive selection in our study, but these were not fixed, apparently escaping the action of purifying selection. Our network analyses revealed branches leading to expanding haplotypes with sites under selection only detected when P.1.1 and P.1.2 were considered. The P.1.2 exclusive haplotype H_5 originated from a non-synonymous mutational step (H3509Y) in H_1 of ORF1a. The selected allele, 3509Y, represents an adaptive novelty involving ORF1a of P.1. Finally, we discuss how phenomena such as epistasis and antagonistic pleiotropy could limit the emergence of new alleles (and combinations thereof) in SARS-COV-2 lineages, maintaining infectivity in humans, while providing rapid response capabilities to face the arms race triggered by host immuneresponses.     

Does vestibular stimulation activate thalamocortical mechanisms that reintegrate impaired cortical regions?

Caloric stimulation induced a transient reversal of multimodal hemispatial cognitive deficits in an 81-year-old woman with an acute left cerebral hemisphere stroke. The patient had unawareness of her right hand (asomatognosia), right-sided visual unawareness (hemineglect), aphasia and right-sided weakness (hemiplegia) prior to the stimulation. Transient improvements in impaired sensory, motor, linguistic and cognitive function developed within 30 s following application of the caloric stimulus and onset of horizontal nystagmus. The effect persisted for 3 min and ceased completely after 5 min. While several recent reports have described the capacity of caloric stimulation to transiently improve or reverse a wide range of attentional, cognitive and motor impairments, most examples are in right-hemisphere-damaged patients with long-standing brain injury. Typically, patients have been tested several months or years after the onset of the deficit. A possible mechanism for the temporary reintegration of multiple cognitive functions in this patient is discussed.     

An association between the acute phase response and patterns of antigen induced T cell proliferation in juvenile idiopathic arthritis

The aim of this research was to determine whether all memory T cells have the same propensity to migrate to the joint in patients with juvenile idiopathic arthritis. Paired synovial fluid and peripheral blood mononuclear cell proliferative responses to a panel of antigens were measured and the results correlated with a detailed set of laboratory and clinical data from 39 patients with juvenile idiopathic arthritis. Two distinct patterns of proliferative response were found in the majority of patients: a diverse pattern, in which synovial fluid responses were greater than peripheral blood responses for all antigens tested; and a restricted pattern, in which peripheral blood responses to some antigens were more vigorous than those in the synovial fluid compartment. The diverse pattern was generally found in patients with a high acute phase response, whereas patients without elevated acute phase proteins were more likely to demonstrate a restricted pattern. We propose that an association between the synovial fluid T cell repertoire and the acute phase response suggests that proinflammatory cytokines may influence recruitment of memory T cells to an inflammatory site, independent of their antigen specificity. Additionally, increased responses to enteric bacteria and the presence of αEβ7 T cells in synovial fluid may reflect accumulation of gut associated T cells in the synovial compartment, even in the absence of an elevated acute phase response. This is the first report of an association between the acute phase response and the T cell population recruited to an inflammatory site.