Abstract
Background
Orbital cellulitis is an invasive infection defined by its location posterior to the orbital septum and can result in severe clinical manifestations. Computed tomography (CT) is ...the recommended imaging modality to assess for extent of disease and the Chandler classification system is used. It has 5 stages (CS): I is preseptal; II has inflammation beyond the orbital septum; III has subperiosteal abscess; IV has orbital abscess; and V has cavernous sinus thrombosis. There is limited data in its association with microbiology culture results. As part of a larger study to capture epidemiological and microbiological trends in pediatric orbital we hypothesize that culture yields and identification of a causative pathogen would increase as CS increases.
Methods
We performed a retrospective analysis using the US Military Health System database. ICD9/10 codes identified Individuals ≤ 21 years from June 2009 to September 2019 with orbital cellulitis. We excluded ophthalmia neonatorum and any cases without radiographic confirmation of orbital involvement. Demographic data, co-morbid diagnoses, imaging studies, microbiology results, and antibiotics prescribed were collected. CT reports were reviewed, and cases grouped by Chandler stage, (CS II-V). Descriptive statistics and χ 2 tests were used for categorical variables when appropriate.
Results
130 cases met the inclusion criteria. 66.9% were male, the median age was 9 years old (IQR 4-17), and 55.4% had a prior diagnosis of sinusitis. 50.7% of cases were classified as CS II, 35.3% as CS III, 13.1% as CS IV, and 0.01% as CS V. Microbiology cultures were positive in 33.8% of cases. There was a significant difference between CS and any culture positivity with p = 0.011 and there was a significant trend between increasing CS and culture positivity with p < 0.003. Staphylococcus aureus and Streptococcus intermedius were the two most commonly identified pathogens, with no significant difference or trend associated with CS.
Conclusion
Overall, our findings demonstrated microbiology yield being low but increases with radiographic characteristics and CS stage. Identification of causative pathogens could increase the likelihood for tailored definitive antimicrobial therapy in pediatric patients with orbital cellulitis.
Disclosures
All Authors: No reported disclosures.
We have examined the role of the acidic residues Asp2 and Glu4 at the NH2 terminus of Saccharomyces cerevisiae actin through site-directed mutagenesis. In DNEQ actin, these residues have been changed ...to Asn2 and Gln4, whereas in delta DSE actin, the Asp2-Ser-Glu tripeptide has been deleted. Both mutant actins can replace wild type yeast actin. Peptide mapping studies reveal that DNEQ, like wild type actin, retains the initiator Met and is NH2 terminally acetylated, whereas delta DSE has a free NH2 terminus and has lost the initiator Met. Interestingly, microscopic examination of filaments of these two actins reveal the appearance of bundled filaments. The DNEQ bundles are smaller and more ordered, whereas the delta DSE bundles are larger and more loosely organized. Additionally, both mutant actins activate the ATPase activity of rabbit muscle myosin S1 fragment to a lesser extent than wild type. We have also developed a sensitive assay for actin function in vivo that enabled us to detect a slight defect in the ability of these mutant actins to support secretion, an important function in yeast. Thus, although the mutant actins resulted in no gross phenotypic changes, we were able to detect a defect in actin function through this assay. From these studies we can conclude that 1) although NH2-terminal negative charges are not essential to yeast life, the loss of such charges does result in a slight defect in the actins' ability to support secretion, 2) removal of the NH2-terminal negative charges promotes the bundling of actin filaments, and 3) actins lacking NH2-terminal negative charges are unable to activate the myosin S1 ATPase activity as well as wild type actin
Granzyme B has been purified to homogeneity from the granules of a human cytolytic lymphocyte line, Q31, in an enzymatically active form by a three-step procedure. Q31 granzyme B hydrolyzed ...Na-t-butyloxycarbonyl-L-alanyl-L-alanyl-L-aspartyl (Boc-Ala-Ala-Asp) thiobenzyl ester with a kcat of 11 +/- 5 mol/s/mol enzyme and catalytic efficiency kcat/Km of 76,000 +/- 44,000 M-1 s-1. The hydrolysis of Boc-Ala-Ala-Asp thiobenzyl ester by crude Q31 Percoll fractions paralleled the tryptase activity for granule-containing fractions, which showed that granzyme B was associated with granules. When chromatographed on Sephacryl S-300, Q31 granzyme B eluted in two broad bands corresponding to dimer and monomer, both of which electrophoresed at 35 kDa in reducing NaDodSo4 polyacrylamide, and both of which showed a lag phase in assays. The lag phase in assays could be extended with 0.03 mM pepstatin. Upon elution from ion-exchange chromatography Q31 granzyme B electrophoresed at 32 kDa in reducing NaDodSO4 polyacrylamide and did not have a lag phase in assays. The amino-terminal sequence of the 32-kDa Q31 granzyme B was identical to four other human cytotoxic T-lymphocyte granzymes B in 18 of 18 positions sequenced. Purified Q31 granzyme B had a preference for substrates with Glu or Asp as the residue amino-terminal to the scissile bond; little or no activity was noted with oligopeptide substrates for trypsin-like, chymotrypsin-like, and elastase-like proteases. Human plasma alpha 1-protease inhibitor, human plasma alpha 2-protease macroglobulin, soybean and lima-bean trypsin inhibitors, bovine aprotinin, phosphoramidon, and chymostatin inhibited Q31 granzyme B. The inhibition by alpha 1-protease inhibitor was rapid enough to be of physiological significance.
Wait times for medical procedures in Canada are universally thought to be too long, particularly for elective procedures. In this paper we point out the conceptual and practical difficulties ...surrounding wait list management in Canada. We suggest that while waits need to exist as a distributive allocation policy, the data to make informed decisions about wait times and their impact on patient care is absent. We also show that current waitlist initiatives lack an underlying conceptual model of why waits occur. The paper concludes with a discussion of why operational research (OR) models are not in greater use for wait list management and suggest a program of research to improve knowledge uptake for OR models.
The goal of the present study was to determine whether there were HIV‐1 specific cellular immune responses among a subgroup of women within a cohort of Nairobi prostitutes (n = 1800) who, despite ...their intense sexual exposure to HIV‐1, are epidemiologically resistant to HIV‐1 infection. Of the 80 women defined to be resistant, 24 were recruited for immunological evaluation. The HIV‐1‐specific T‐helper responses were determined by IL‐2 production following stimulation with HIV‐1 envelope peptides and soluble gp120. Cytotoxic T lymphocyte responses were determined by lysis of autologous EBV‐transformed B cell lines infected with control vaccinia virus or recombinant vaccinia viruses containing the HIV‐1 structural genes env, gag and pol. Resistant women had significantly increased HIV‐1 specific T‐helper responses, as determined by in vitro IL‐2 production to HIV‐1 envelope peptides and soluble glycoprotein 120, compared with low‐risk seronegative and HIV‐1‐infected controls (P ≤ 0.01, Student's t‐test). Seven of the 17 (41%) resistant women showed IL‐2 stimulation indices ≥ 2.0. HIV‐1‐specific CTL responses were detected among 15/22 (68.2%) resistant women compared with 0/12 low‐risk controls (Chi‐squared test, P < 0.001). In the two resistant individuals tested, the CTL activity was mediated by CD8+ effectors. Many HIV‐1‐resistant women show evidence of HIV‐1‐specific T‐helper and cytotoxic responses. These data support the suggestion that HIV‐1‐specific T‐cell responses contribute to protection against HIV‐1 infection.
One indication of entanglement between two particles is a change in parity or spin in one when the other is changed in order to maintain constancy of the system. Our experiment was designed to ...discern if this phenomenon occurred at the macroscopic level between the electroencephalographic activities of brains of pairs of people, separated by about 75 m, with various degrees of "entanglement". About 50% of the variance of the "simultaneous" electroencephalographic power was shared between pairs of brains. Pairs of strangers were positively correlated within alpha and gamma bands within the temporal and frontal lobes. However the power levels within the alpha and theta bands were negatively correlated for pairs of people who had a protracted history of interaction. The latter result might be considered support for the hypothesis of macroscopic entanglement.
We employ P to S converted waveforms to investigate effects of the hot mantle plume on seismic discontinuities of the crust and upper mantle. We observe the Moho at depths between 13 and 17 km, ...regionally covered by a strong shallow intracrustal converted phase. Coherent phases on the transverse component indicate either dipping interfaces, 3-D heterogeneities or lower crustal anisotropy. We find anomalies related to discontinuities in the upper mantle down to the transition zone evidently related to the hot mantle plume. Lithospheric thinning is confirmed in greater detail than previously reported by Li et al., and we determine the dimensions of the low-velocity zone within the asthenosphere with greater accuracy. Our study mainly focuses on the temperature-pressure dependent discontinuities of the upper mantle transition zone. Effects of the hot diapir on the depths of mineral phase transitions are verified at both major interfaces at 410 and 660 km. We determine a plume radius of about 200 km at the 660 km discontinuity with a core zone of about 120 km radius. The plume conduit is located southwest of Big Island. A conduit tilted in the northeast direction is required in the upper mantle to explain the observations. The determined positions of deflections of the discontinuities support the hypothesis of decoupled upper and lower mantle convection.
The role that potassium channels play in human T lymphocyte activation has been investigated by using specific potassium channel probes. Charybdotoxin (ChTX), a blocker of small conductance ...Ca(2+)-activated potassium channels (PK,Ca) and voltage-gated potassium channels (PK,V) that are present in human T cells, inhibits the activation of these cells. ChTX blocks T cell activation induced by signals (e.g., anti-CD2, anti-CD3, ionomycin) that elicit a rise in intracellular calcium (Ca2+i) by preventing the elevation of Ca2+i in a dose-dependent manner. However, ChTX has no effect on the activation pathways (e.g., anti-CD28, interleukin 2 IL-2) that are independent of a rise in Ca2+i. In the former case, both proliferative response and lymphokine production (IL-2 and interferon gamma) are inhibited by ChTX. The inhibitory effect of ChTX can be demonstrated when added simultaneously, or up to 4 h after the addition of the stimulants. Since ChTX inhibits both PK,Ca and PK,V, we investigated which channel is responsible for these immunosuppressive effects with the use of two other peptides, noxiustoxin (NxTX) and margatoxin (MgTX), which are specific for PK,V. These studies demonstrate that, similar to ChTX, both NxTX and MgTX inhibit lymphokine production and the rise in Ca2+i. Taken together, these data provide evidence that blockade of PK,V affects the Ca(2+)-dependent pathways involved in T lymphocyte proliferation and lymphokine production by diminishing the rise in Ca2+i that occurs upon T cell activation.
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