Herpes simplex virus infection of the adult lower respiratory tract

We have reported six adult patients with HSV infection of the lower respiratory tract diagnosed ante-mortem, and have reviewed the literature on this subject. An attempt has been made to define the natural history of the infection, and suggestions have been made regarding diagnosis and treatment. HSV can infect the lower respiratory tract in immunologically normal patients, as well as the immunocompromised host. Many patients have been burned, or intubated, or have other reasons for squamous metaplasia of the respiratory epithelium. The pathogenesis in many cases is an extension or aspiration of oropharyngeal HSV, but there is a suggestion that some cases may be hematogenously spread. The diagnosis of the site and presence of HSV infection should be based initially on cytologic findings, histologic findings, or both. Viral cultures or immunofluorescent or immunoperoxidase labeling can be used to confirm the cytologic and histologic diagnoses. Bronchoscopy is valuable for visualizing ulcerations or membranes in the respiratory tract, and for improving the sensitivity and specificity of the cytologic diagnosis. Because the process is most often focused in the tracheobronchial tree, percutaneous needle biopsy and open lung biopsy may be less sensitive than bronchoscopy. Standard serologic tests are, in general, not helpful diagnostically. They can help verify that a recent HSV infection has occurred, but do not differentiate between primary and recurrent infection, and do not help in localizing the site of infection. However, paired complement fixation or neutralizing antibody titers may be useful prognostically. If the titers do not rise in the presence of a documented HSV lower respiratory tract infection, the outcome is more likely to be fatal. The respiratory epithelium from the oral mucosa to the alveoli can be infected with HSV. The manifestations can range from a few scattered ulcers in the trachea to a severe ulcerative process resulting in an obstructing, inflammatory tracheobronchial membrane. Focal or diffuse pneumonia can also occur. No specific treatment for the illness can be recommended at this time. There is no evidence that currently available antiviral therapy is effective. The outcome of the illness seems to be largely dependent on the immunologic status of the host, complicating superinfections, and the progression of the underlying disease.     

Genetic polymorphism PC-1 K121Q and ethnic susceptibility to insulin resistance

Genetic susceptibility may be responsible for high prevalence of insulin resistance in Asian Indians. This study was carried out in samples of local Asian Indians and Caucasians to determine whether plasma cell membrane glycoprotein (PC)-1 K121Q and insulin receptor substrate-1 (IRS-1) G972A polymorphisms contribute significantly to susceptibility to insulin resistance in Asian Indians. The frequency of carrying at least one copy of the PC-1 121Q variant in Asian Indians was significantly higher than that in Caucasians (P = 0.01), but the frequency was similar for IRS-1 972A (6% and 7%). A significantly higher insulin area under the curve during oral glucose tolerance testing (P < 0.0001) and lower insulin sensitivity during hyperinsulinemic-euglycemic clamps (P = 0.04) were found in Asian Indians with PC-1 121Q variant compared with Asian Indians with wild-type PC-1 and with Caucasians with or without the polymorphism. IRS-1 972A was not associated with any change in insulin sensitivity. We conclude that the PC-1 K121Q polymorphism associates with primary insulin resistance in migrant Asian Indians. A relatively high frequency of this polymorphism thus may be one factor contributing to insulin resistance susceptibility in Asian Indians. This finding indicates the need for expanded studies on the association between PC-1 K121Q and insulin resistance in a representative sample of the Asian Indian population.     

Enhancement of chemotactic factor-stimulated neutrophil oxidative metabolism by leukotriene B4

Leukotriene B4 (LTB4) is a potent primary stimulator of neutrophil chemotaxis, aggregation, and degranulation and induces superoxide production at higher concentrations. In order to determine whether LTB4 modulates neutrophil responses to oxidative stimuli, human neutrophils (PMNs) were incubated with LTB4 prior to stimulation with f-Met-Leu-Phe (fMLP, 10(-7) mol/L), opsonized zymosan (OZ, 250 micrograms/mL), or phorbol myristate acetate (PMA, 32 nmol/L). Superoxide (O2-) production by stimulated PMNs was assessed by the superoxide dismutase-inhibitable reduction of cytochrome c. LTB4 alone did not stimulate O2- production in concentrations below 10(-7) mol/L and had no effect on the O2- assay. In the concentration range of 10(-12) to 10(-8) mol/L, LTB4 did not alter O2- release induced by OZ or PMA. In contrast, LTB4-treated cells demonstrated enhanced O2- production following exposure to fMLP, and in the presence of 10 nmol/LLTB4, generated 180% +/- 41% of O-2 quantities produced by control cells (n = 23). Enhancement was LTB4 dose-dependent, was maximal in the range of 1 to 10 nmol/L LTB4, was not reversed by removal of the lipid from the medium prior to fMLP stimulation, and was not dependent on the presence of Ca++ or Mg++ in the suspending medium. Chemiluminescence of fMLP-stimulated neutrophils was increased to 323% of controls in neutrophils preincubated with 10 nmol/L LTB4. Unlike augmentation of oxidative responses to fMLP seen with other degranulating stimuli, enhancement by LTB4 was not correlated with an increase in 3H-fMLP receptor binding. These results indicate that, in addition to its primary effects on neutrophil function, LTB4 modulates PMN oxidative responses to the chemotactic peptide and, thus, may amplify the release of oxygen metabolites at inflammatory foci.     

Normal synthesis and expression of endothelial IIb/IIIa in Glanzmann's thrombasthenia

Glanzmann's thrombasthenia is a bleeding disorder, inherited in an autosomal recessive way and characterized by an absence or deficiency of the platelet glycoprotein (GP) IIb/IIIa complex. Recently, we and others demonstrated that cultured human umbilical vein endothelial cells synthesized a membrane protein complex similar to the platelet GP IIb/IIIa complex. In this article, we demonstrate that endothelial cells isolated from the umbilical vein of a newborn with Glanzmann's thrombasthenia, as compared with normal endothelial cells, show no difference in their ability to synthesize and express this GP IIb/IIIa complex. Our results indicate that Glanzmann's thrombasthenia is not accompanied by an "endotheliopathy."     

von Willebrand disease "Vicenza" with larger-than-normal (supranormal) von Willebrand factor multimers

When normal volunteers or patients with type I von Willebrand disease (VWD) are given desmopressin (DDAVP), a set of larger-than-normal (supranormal) von Willebrand factor (VWF) multimers, similar to those present in VWF-containing cells such as platelets megakaryocytes and endothelial cells, appear transiently in postinfusion plasma. In two kindreds with mild lifelong bleeding symptoms transmitted as an autosomal dominant trait, all ten symptomatic members (but none of the five asymptomatic members) had a supranormal multimeric structure for plasma VWF, apparently identical to that seen for postdesmopressin normal plasma. Plasma factor VIII coagulant activity (VIII:C), VWF antigen (VWF:Ag), ristocetin-induced platelet agglutination, and ristocetin cofactor (RiCof) activity were low. Platelet VWF:Ag and RiCof levels (tested for three patients only) were normal. Bleeding times were normal or slightly prolonged. The patients' platelet multimeric structure was the same as that for normal platelets. After desmopressin infusion the plasma VWF multimeric structure remained supranormal as for preinfusion plasma, with VIII:C VWF:Ag and RiCof increasing markedly over baseline values and disappearing at a normal rate. Examination of the VWF subunit composition from three of these patients indicated that proteolytic processing of their VWF did not differ from normal. This study describes the first variant of VWD with a supranormal multimeric structure.     

Pathoscope: Species identification and strain attribution with unassembled sequencing data

Emerging next-generation sequencing technologies have revolutionized the collection of genomic data for applications in bioforensics, biosurveillance, and for use in clinical settings. However, to make the most of these new data, new methodology needs to be developed that can accommodate large volumes of genetic data in a computationally efficient manner. We present a statistical framework to analyze raw next-generation sequence reads from purified or mixed environmental or targeted infected tissue samples for rapid species identification and strain attribution against a robust database of known biological agents. Our method, Pathoscope, capitalizes on a Bayesian statistical framework that accommodates information on sequence quality, mapping quality, and provides posterior probabilities of matches to a known database of target genomes. Importantly, our approach also incorporates the possibility that multiple species can be present in the sample and considers cases when the sample species/strain is not in the reference database. Furthermore, our approach can accurately discriminate between very closely related strains of the same species with very little coverage of the genome and without the need for multiple alignment steps, extensive homology searches, or genome assembly—which are time-consuming and labor-intensive steps. We demonstrate the utility of our approach on genomic data from purified and in silico “environmental” samples from known bacterial agents impacting human health for accuracy assessment and comparison with other approaches.The accurate and rapid identification of species and strains of pathogens is an essential component of biosurveillance from both human health and biodefense perspectives (Vaidyanathan 2011). For example, misidentification was among the issues that resulted in a 3-wk delay in accurate diagnosis of the recent outbreak of hemorrhagic Escherichia coli being due to strain O104:H4, resulting in over 3800 infections across 13 countries in Europe with 54 deaths (Frank et al. 2011). The most accurate diagnostic information, necessary for species identification and strain attribution, comes from the most refined level of biological data—genomic DNA sequences (Eppinger et al. 2011). Advances in DNA-sequencing technologies allows for the rapid collection of extraordinary amounts of genomic data, yet robust approaches to analyze this volume of data are just developing, from both statistical and algorithmic perspectives.Next-generation sequencing approaches have revolutionized the way we collect DNA sequence data, including for applications in pathology, bioforensics, and biosurveillance. Given a particular clinical or metagenomic sample, our goal is to identify the specific species, strains, or substrains present in the sample, as well as accurately estimate the proportions of DNA originating from each source genome in the sample. Current approaches for next-gen sequencing usually have read lengths between 25 and 1000 bp; however, these sequencing technologies include error rates that vary by approach and by samples. Such variation is typically less important for species identification given the relatively larger genetic divergences among species than among individuals within species. But for strain attribution, sequencing error has the potential to swamp out discriminatory signal in a data set, necessitating highly sensitive and refined computational models and a robust database for both species identification and strain attribution.Current methods for classifying metagenomic samples rely on one or more of three general approaches: composition or pattern matching (McHardy et al. 2007; Brady and Salzberg 2009; Segata et al. 2012), taxonomic mapping (Huson et al. 2007; Meyer et al. 2008; Monzoorul Haque et al. 2009; Gerlach and Stoye 2011; Patil et al. 2012; Segata et al. 2012), and whole-genome assembly (Kostic et al. 2011; Bhaduri et al. 2012). Composition and pattern-matching algorithms use predetermined patterns in the data, such as taxonomic clade markers (Segata et al. 2012), k-mer frequency, or GC content, often coupled with sophisticated classification algorithms such as support vector machines (McHardy et al. 2007; Patil et al. 2012) or interpolated Markov Models (Brady and Salzberg 2009) to classify reads to the species of interest. These approaches require intensive preprocessing of the genomic database before application. In addition, the classification rule and results can often change dramatically depending on the size and composition of the genome database.Taxonomy-based approaches typically rely on a “lowest common ancestor” approach (Huson et al. 2007), meaning that they identify the most specific taxonomic group for each read. If a read originates from a genomic region that shares homology with other organisms in the database, the read is assigned to the lowest taxonomic group that contains all of the genomes that share the homologous region. These methods are typically highly accurate for higher-level taxonomic levels (e.g., phylum and family), but experience reduced accuracy at lower levels (e.g., species and strain) (Gerlach and Stoye 2011). Furthermore, these approaches are not informative when the reads originate from one or more species or strains that are closely related to each other or different organisms in the database. In these cases, all of the reads can be reassigned to higher-level taxonomies, thus failing to identify the specific species or strains contained in the sample.Assembly-based algorithms can often lead to the most accurate strain identification. However, these methods also require the assembly of a whole genome from a sample, which is a computationally difficult and time-consuming process that requires large numbers of reads to achieve an adequate accuracy—often on the order of 50–100× coverage of the target genome (Schatz et al. 2010). Given current sequencing depths, obtaining this level of coverage is usually possible for purified samples, but coverage levels may not be sufficient for mixed samples or in multiplexed sequencing runs. Assembly approaches are further complicated by the fact that data collection at a crime scene or hospital might include additional environmental components in the biological sample (host genome or naturally occurring bacterial and viral species), thus requiring multiple filtering and alignment steps in order to obtain reads specific to the pathogen of interest.Here we describe an accurate and efficient approach to analyze next-generation sequence data for species identification and strain attribution that capitalizes on a Bayesian statistical framework implemented in the new software package Pathoscope v1.0. Our approach accommodates information on sequence quality, mapping quality, and provides posterior probabilities of matches to a known database of reference genomes. Importantly, our approach incorporates the possibility that multiple species can be present in the sample or that the target strain is not even contained within the reference database. It also accurately discriminates between very closely related strains of the same species with much less than 1× coverage of the genome and without the need for sequence assembly or complex preprocessing of the database or taxonomy. No other method in the literature can identify species or substrains in such a direct and automatic manner and without the need for large numbers of reads. We demonstrate our approach through application to next-generation DNA sequence data from a recent outbreak of the hemorrhagic E. coli (O104:H4) strain in Europe (Frank et al. 2011; Rohde et al. 2011; Turner 2011) and on purified and in silico mixed samples from several other known bacterial agents that impact human health. Software and data examples for our approach are freely available for download at https://sourceforge.net/projects/pathoscope/.     

Return to sporting activity after Birmingham hip resurfacing arthroplasty: Mid term results

Background:

Hip resurfacing arthroplasty (HRA) is primarily indicated for young, active patients with disabling coxarthrosis who wish to remain active and return to sports after surgery. Relatively few prospective studies have assessed return to sporting activity and impact of gender and age on this.

Materials and Methods:

Seventy-nine consecutive patients treated with HRA were included. Patients were reviewed clinically and radiologically. Function was assessed using the modified University of California Los Angeles (UCLA) activity score. The Oxford, Harris and WOMAC hip scores were calculated.

Results:

Average age at the time of surgery was 54.9 years (range 34.5–73.6 years). Average preoperative and postoperative UCLA scores were 4 and 7.6 respectively. Patients were involved in 2 (0–4) sporting activities preoperatively and 2 (0–5) postoperatively. Preoperative and postoperative Oxford Hip Scores, Harris Hip Score and WOMAC scores were 40, 46 and 51 and 16, 94 and 3 respectively (P < 0.0001). Patients returned to sports at an average of 3 months postoperatively.

Conclusion:

Patients were able to return to sports by 3 months and perform the same number of activities at preoperative intensity. Activity levels are maintained up to the medium term with few complications.