The heteroduplex mobility assay (HMA) as a pre-sequencing screen for Norwalk-like viruses

Molecular epidemiological studies of Norwalk-like viruses (NLVs), previously known as small round structured viruses (SRSVs), are dependant currently on DNA sequencing of PCR amplicons, which is expensive and time consuming. The Heteroduplex Mobility assay (HMA) was evaluated as a method for identification of PCR amplicons from the commonly circulating NLV strains without DNA sequencing. The procedure was developed for use with two reference strains, a Mexico virus-like strain (MXV-like; Hu?NLV?RBH?1993?UK) and the Grimsby virus strain (Hu?NLV?Gimsby?1995?UK), and was optimised with regards to the annealing and electrophoresis conditions and the electrophoresis gel matrix. Using the optimised conditions, amplicons of less than 90% sequence identity formed visible heteroduplexes, allowing the strains to be placed into three categories; Mexico-like, Grimsby-like and non-Mexico virus/non-Grimsby virus strains. Outbreak strains 'genotyped' previously by DNA sequencing as Mexico virus or Grimsby virus were identified correctly by the heteroduplex mobility assay. The procedure was applied prospectively to strains from 130 outbreaks occurring in the UK between 1997 and 1998. Heteroduplex mobility assay was successful on 120 (92%) strains of which 68 (57%) were GRV-like strains, three (2.5%) were Mexico virus-like strains and 49 (41%) were categorised as non- Mexico/non-Grimsby virus strains. Amplicons from 50 of the 120 strains were sequenced and there was perfect correlation between the heteroduplex mobility assay categorisation and phylogenetic analysis. HMA offers a rapid, robust and far cheaper alternative to sequencing for the identification of prevalent Norwalk-like virus genotypes for molecular epidemiological studies.     

Cutaneous New World Leishmaniasis on a Port-wine stain birthmark

We present an interesting case report of two sarcoid-like lesions on a port-wine stain (PWS) birthmark in a Brazilian patient which on investigation proved to be cutaneous leishmaniasis.     

Geometrical Measurement of Central Tumor Location in cT1N0M0 NSCLC Predicts N1 but Not N2 Upstaging

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The oxygen reserve index (ORI): a new tool to monitor oxygen therapy

Supplemental oxygen is administered in the vast majority of patients in the perioperative setting and in the intensive care unit to prevent the potentially deleterious effects of hypoxia. On the other hand, the administration of high concentrations of oxygen may induce hyperoxia that may also be associated with significant complications. Oxygen therapy should therefore be precisely titrated and accurately monitored. Although pulse oximetry has become an indispensable monitoring technology to detect hypoxemia, its value in assessing the oxygenation status beyond the range of maximal arterial oxygen saturation (SpO₂ ≥97%) is very limited. In this hyperoxic range, we need to rely on blood gas analysis, which is intermittent, invasive and sometimes delayed. The oxygen reserve index (ORI) is a new continuous non-invasive variable that is provided by the new generation of pulse oximeters that use multi-wavelength pulse co-oximetry. The ORI is a dimensionless index that reflects oxygenation in the moderate hyperoxic range (PaO₂ 100–200 mmHg). The ORI may provide an early alarm when oxygenation deteriorates well before any changes in SpO₂ occur, may reflect the response to oxygen administration (e.g., pre-oxygenation), and may facilitate oxygen titration and prevent unintended hyperoxia. In this review we describe this new variable, summarize available data and preliminary experience, and discuss its potential clinical utilities in the perioperative and intensive care settings.     

Characteristics of Asthma Patients Admitted to an Intermediate Respiratory Care Unit

IntroductionIntermediate respiratory care units (IRCU) provide continuous monitoring and non-invasive mechanical ventilation (NIMV) in patients with severe respiratory failure who are usually admitted to intensive care units (ICUs). The usefulness of IRCU in managing severe asthma exacerbations has never been evaluated.MethodsClinical data were prospectively and systematically compiled from patients admitted to the IRCU with a principal diagnosis of bronchial asthma exacerbation. We assessed therapeutic failure (intubation or exitus) and patient evolution up until 6 months after discharge compared with a group of patients admitted to a conventional hospital ward, paired for age and sex, and with the same principal diagnosis.ResultsA total of 74 asthma patients were included (37 admitted to IRCU and 37 to the hospital ward) with a mean age (±SD) of 58 ± 20, who were predominantly women (67%), with previous diagnosis of asthma and persistent asthma treatment. The main cause of admittance to the IRCU was severe respiratory failure. The patients who were admitted to the IRCU presented more radiological affectation (alveolar infiltrates) and had significantly higher pCO₂. Ten patients admitted to the IRCU required non-invasive mechanical ventilation (NIMV). There were no differences between the two groups regarding either therapeutic failure or the 6-month follow-up after discharge.ConclusionsPatients with severe asthma exacerbations can be managed in an IRCU while avoiding hospitalization in an ICU and demonstrating a prognosis similar to milder exacerbations treated in conventional hospital wards.