High Viral Diversity and Mixed Infections in Cerebral Spinal Fluid From Cases of Varicella Zoster Virus Encephalitis

Background

Varicella zoster virus (VZV) may cause encephalitis, both with and without rash. Here we investigate whether viruses recovered from the central nervous system (CNS; encephalitis or meningitis) differ genetically from those recovered from non-CNS samples.

Methods

Enrichment-based deep sequencing of 45 VZV genomes from cerebral spinal fluid (CSF), plasma, bronchoalveolar lavage (BAL), and vesicles was carried out with samples collected from 34 patients with and without VZV infection of the CNS.

Results

Viral sequences from multiple sites in the same patient were identical at the consensus level. Virus from vesicle fluid and CSF in cases of meningitis showed low-level diversity. By contrast, plasma, BAL, and encephalitis had higher numbers of variant alleles. Two CSF-encephalitis samples had high genetic diversity, with variant frequency patterns typical of mixed infections with different clades.

Conclusions

Low viral genetic diversity in vesicle fluid is compatible with previous observations that VZV skin lesions arise from single or low numbers of virions. A similar result was observed in VZV from cases of VZV meningitis, a generally self-limiting infection. CSF from cases of encephalitis had higher diversity with evidence for mixed clade infections in 2 cases. We hypothesize that reactivation from multiple neurons may contribute to the pathogenesis of VZV encephalitis.

Affinity apheresis for treatment of bacteremia caused by Staphylococcus aureus and/or methicillin-resistant S. aureus (MRSA)

Staphylococcus aureus (SA) bacteremia is associated with high mortality, and often results in metastatic infections. The methicillin-resistant SA (MRSA) is an urgent health care issue, as nosocomial infections with these bacteria represent limited treatment alternatives. Samples of whole blood containing challenge inoculums of SA and MRSA strains were passed through columns packed with surface-heparinized polyethylene beads. The bound bacteria were eluted and quantitatively determined by culturing and by real-time PCR. Significant amounts of both SA and MRSA adhered to the heparinized beads (more than 65% of inoculated bacteria). After rinsing with buffer at high ionic strength, viable bacteria or bacterial DNA were eluted from the columns, indicating that the binding was specific. The conclusions that can be made from these experiments are that, as earlier reported in the literature, the high affinity of SA to heparin is retained in whole blood, and MRSA in whole blood binds to heparin with similar or higher affinity than SA. It should be possible to lower the amount of SA and/or MRSA from the blood of infected patients to levels that could be taken care of by the immune system. In previous studies, we have shown that passing blood from septic patients over beads coated with end-point-attached, biologically active heparin is a useful technique for regulating the levels of heparin-binding cytokine. These findings in combination with the present findings indicate the possibility of creating an apheresis technology for treatment of sepsis caused by SA and/or MRSA.

Molecular basis for resistance of herpes simplex virus type 1 mutants to the sulfated oligosaccharide inhibitor PI-88

Herpes simplex virus type 1 variants selected by virus propagation in cultured cells in the presence of the sulfated oligosaccharide PI-88 were analyzed. Many of these variants were substantially resistant to the presence of PI-88 during their initial infection of cells and/or their cell-to-cell spread. Nucleotide sequence analysis revealed that the deletion of amino acids 33-116 of gC but not lack of gC expression provided the virus with selective advantage to infect cells in the presence of PI-88. Purified gC (Delta33-116) was more resistant to PI-88 than unaltered protein in its binding to cells. Alterations that partly contributed to the virus resistance to PI-88 in its cell-to-cell spread activity were amino acid substitutions Q27R in gD and R770W in gB. These results suggest that PI-88 targets several distinct viral glycoproteins during the course of initial virus infection and cell-to-cell spread.

Income prospects and age-at-marriage

"This paper provides an empirical investigation of a theoretical model of the marriage market. In the model, women are valued more for their ability to bear children and men are valued more for the ability to make money. Men cannot reveal their labor market ability to potential spouses until they enter the labor force. At the same time, the relevant information for evaluating females as spouses is revealed at a younger age. The model predicts that the income of males will be positively associated with age-at-first-marriage. We find empirical support for the model [based on U.S. data]. However, we also find the association between male earnings and age-at-first-marriage becomes negative for those who married after age 30, which was not predicted by the model. Consistent with the model, we do not find a strong relationship between earnings and age-at-first-marriage among females."

Prevalent attitudes regarding residency training in ocular anesthesia

PURPOSE

To determine the current level of formal training in ocular anesthesia provided to nonophthalmologist physicians, the rationale for this training or lack thereof, and the perceived need for this training by anesthesia residency training programs.

METHODS

A two-page survey questionnaire was forwarded to all residency directors of ophthalmology and anesthesia training programs listed with the American Medical Association. A second mailing followed 2 months after the initial mailing if no response was received from a particular program.

RESULTS

An overwhelming response of 92% of ophthalmology programs and 76% of anesthesiology programs was achieved. In 93% of ophthalmology programs and 77% of anesthesiology programs, no formal training was provided to nonophthalmologist physicians in retrobulbar or peribulbar anesthesia. In addition, 78% of ophthalmology and 65% of anesthesiology programs denied having any plans to provide this training even though 40% of the anesthesia departments wanted to initiate and coordinate such training.

CONCLUSIONS

Currently, few ophthalmology programs offer formal training to anesthesiology residents in ocular anesthesia. Following are the predominant factors involved in this decision: (1) the operating surgeon is ultimately responsible for any complications; (2) there is a lack of knowledge of orbital anatomy and axial eye length by anesthesia personnel; and, most importantly, (3) there is a brief episodic nature in which anesthesia residents encounter ophthalmologic procedures resulting in minimal opportunities for training and experience from which the residency training program could ensure quality outcome and proper credentialling.

Recovering event histories by cubic spline interpolation

If event data are recorded in discrete intervals of time, errors are introduced when the data are converted from the unit in which they were recorded, such as date, to another unit such as age or duration. The problem is illustrated by the inconsistent age at marriage schedules published by 2 recent US censuses. This paper develops a general method for treating problems of this type using cubic spline interpolation. The method is used to adjust US age at marriage schedules, explaining a substantial part of the discrepancy in the 1960 and 1970 censuses.

Exclusion gene mapping utilizing patients with chromosome imbalance: the HL-A system as a prototype

17 chromosomally unbalanced patients, their siblings and parents were tested for HL-A types and for up to 25 other polymorphic systems to determine whether there was gain or loss of an allele concurrent with the gain or loss of chromosome material. 5 patients had trisomy of part or all of a chromosome; 2 had trisomy of a segment and also deletion of chromosome material. All 7 were due to a familial translocation. The remaining patients had small deletions; 5 had ring chromosomes, 4 had rod deletions and 1 had missing chromosome material due to a heritable translocation. All cases were informative at the HL-A loci because of the high degree of polymorphism of the system whereas only some of the other systems were informative. None of the 17 patients showed unusual inheritance of HL-A or any other of the polymorphic systems examined. These results provide evidence excluding the HL-A and other loci from a number of possible locations in the human genome.