Streaked sub-ps-resolution x-ray line shapes and implications for solid-density plasma dynamics (invited).

A high-resolution x-ray spectrometer was coupled with an ultrafast x-ray streak camera to produce time-resolved line shape spectra measured from hot, solid-density plasmas. A Bragg crystal was placed near laser-produced plasma to maximize throughput; alignment tolerances were established by ray tracing. The streak camera produced single-shot, time-resolved spectra, heavily sloped due to photon time-of-flight differences, with sufficient reproducibility to accumulate photon statistics. The images are time-calibrated by the slope of streaked spectra and dewarped to generate spectra emitted at different times defined at the source. The streaked spectra demonstrate the evolution of spectral shoulders and other features on ps timescales, showing the feasibility of plasma parameter measurements on the rapid timescales necessary to study high-energy-density plasmas.

Widespread Wolbachia infection in an insular radiation of damselflies (Odonata, Coenagrionidae).

Wolbachia is one of the most common endosymbionts found infecting arthropods. Theory predicts symbionts like Wolbachia will be more common in species radiations, as host shift events occur with greatest frequency between closely related species. Further, the presence of Wolbachia itself may engender reproductive isolation, and promote speciation of their hosts. Here we screened 178 individuals belonging to 30 species of the damselfly genera Nesobasis and Melanesobasis - species radiations endemic to the Fiji archipelago in the South Pacific - for Wolbachia, using multilocus sequence typing to characterize bacterial strains. Incidence of Wolbachia was 71% in Nesobasis and 40% in Melanesobasis, and prevalence was also high, with an average of 88% in the Nesobasis species screened. We identified a total of 25 Wolbachia strains, belonging to supergroups A, B and F, with some epidemic strains present in multiple species. The occurrence of Wolbachia in both males and females, and the similar global prevalence found in both sexes rules out any strong effect of Wolbachia on the primary sex-ratio, but are compatible with the phenotype of cytoplasmic incompatibility. Nesobasis has higher species richness than most endemic island damselfly genera, and we discuss the potential for endosymbiont-mediated speciation within this group.

Development and Validation of Two Screening Assays for the Hepatitis C Virus NS3 Q80K Polymorphism Associated with Reduced Response to Combination Treatment Regimens Containing Simeprevir.

Persons with hepatitis C virus (HCV) genotype 1a (GT1a) infections harboring a baseline Q80K polymorphism in nonstructural protein 3 (NS3) have a reduced virologic response to simeprevir in combination with pegylated interferon-alfa and ribavirin. We aimed to develop, validate, and freely disseminate an NS3 clinical sequencing assay to detect the Q80K polymorphism and potentially other HCV NS3 drug resistance mutations. HCV RNA was extracted from frozen plasma using a NucliSENS easyMAG automated nucleic acid extractor, amplified by nested reverse transcription-PCR, and sequenced using Sanger and/or next-generation (MiSeq) methods. Sanger chromatograms were analyzed using in-house software (RECall), and nucleotide mixtures were called automatically. MiSeq reads were iteratively mapped to the H77 reference genome, and consensus NS3 sequences were generated with nucleotides present at >20% called as mixtures. The accuracy, precision, and sensitivity for detecting the Q80K polymorphism were assessed in 70 samples previously sequenced by an external laboratory. A comparison of the sequences generated by the Sanger and MiSeq methods with those determined by an external lab revealed >98.5% nucleotide sequence concordance and zero discordant calls of the Q80K polymorphism. The results were both highly repeatable and reproducible (>99.7% nucleotide concordance and 100% Q80K concordance). The limits of detection (>2 and ∼5 log10 IU/ml for the Sanger and MiSeq assays, respectively) are sufficiently low to allow genotyping in nearly all chronically infected treatment-naive persons. No systematic bias in the under- or overamplification of minority variants was observed. Coinfection with other viruses (e.g., HIV and hepatitis B virus [HBV]) did not affect the assay results. The two independent HCV NS3 sequencing assays with the automated analysis procedures described here are useful tools to screen for the Q80K polymorphism and other HCV protease inhibitor drug resistance mutations.

A pilot study: are dental hygienists in Texas ready for the elderly population explosion?

PURPOSE: At the beginning of the 20th century, people 65 and older comprised 4.1% of the population. By the year 2030, it is estimated that people 65 and older, the 'Baby Boomer' generation, will comprise more than 20% of the population. This will have a profound effect on the practice of dentistry and on society as a whole. The purpose of this study was to determine whether dental hygienists in Texas felt prepared and willing to treat the elderly in alternative practice settings such as nursing homes. METHODS: After institutional review board approval, a questionnaire was mailed to 500 hygienists. A 5% systematic sample of dental hygiene graduates was taken from four dental hygiene schools in Texas, United States of America (USA). Of these, 175 were returned for a 35% response rate. Questions asked were degree held, how prepared the participants felt to treat the special needs of the elderly, if participants were willing to work in alternative practice settings such as a nursing home and if they felt additional education was needed. Frequency distributions, correlations and chi square were used to analyse the data. RESULTS: Results revealed 86.5% of the respondents felt prepared to somewhat prepared to treat the special needs of the elderly based on education; equally, 86.5% felt more education was needed to better prepare them to treat the elderly. Over half of the respondents would not be willing to work in alternative practice settings such as nursing homes. CONCLUSION: The average respondents do not feel fully prepared to treat the elderly with special needs, and they think more education is needed to better prepare them to treat this important target population.

Larval aquatic and terrestrial mites infesting parthenogenetic Ischnura hastata (Odonata: Coenagrionidae) from the Azores islands.

We report here the prevalence of parasitism by water mites (Arrenurus sp.) and terrestrial mites (Leptus killingtoni) on parthenogenetic Ischnura hastata (Odonata: Coenagrionidae) from the Azores islands. Leptus killingtoni was only found on the island of Pico, and the prevalence of infestation was highly variable among the different ponds studied, ranging from 0 to 41%. Leptus killingtoni was observed on three of the four odonate species from the archipelago: I. hastata, I. pumilio, and Sympetrum fonscolombii, all of them new hosts for this species. Aquatic mites have been found parasitizing I. hastata females on the island of São Miguel. The prevalence of mite parasitism by Arrenurus sp. on I. hastata was very low, ranging from 12% (2003) to 1% (2008), and in most of the studied ponds, no mites were found attached to females. Although I. hastata coexists with a sexual congener species in the Azores (I. pumilio), they are syntopic in only a small fraction of ponds. Therefore, a comparison between I. hastata and I. pumilio was insufficient to test the predictions of the Red Queen Hypothesis, and further research on parasitism rates in both species needs to be done. In any case, the low prevalence of mite parasitism found in the Azores, coupled with the fact that most of the populations in the archipelago are almost free from competitors and predators, could explain the persistence of these I. hastata parthenogenetic populations, despite their low levels of genetic variation.

Preservation of basophils in dapsone-induced agranulocytosis suggests a possible pathogenetic role for leucocyte peroxidases.

We describe a hitherto unreported laboratory observation, namely the selective preservation of basophils, in a case of severe dapsone-induced agranulocytosis. Dapsone is known to be metabolised by peroxidases to nitroso derivatives in non-hemopoietic cells where these can in turn act as haptens. Our observation that basophils are selectively spared in this syndrome supports the hypothesis that leucocyte peroxidases function in a similar way to facilitate the pathogenesis of this form of agranulocytosis in susceptible individuals.

The lactate paradox in human high-altitude physiological performance.

For many years, physiologists have puzzled over the observation that, during maximum aerobic exercise, high-altitude natives generate lower-than-expected amounts of lactate; the higher the altitude, the lower the postexercise blood lactate peak. This paradoxical situation may be caused mainly by upregulated metabolic control contributions from cell ATP demand and ATP supply pathways.

Antrochoanal polyps in children.

Although relatively rare, antrochoanal polyps represent one of the most common types of polyp diagnosed in children without cystic fibrosis. In an attempt to better define this entity and discuss treatment options, the histories and operative reports of all 25 children (aged 17 years and younger) diagnosed with an antrochoanal polyp between 1970 and 1997 at our institution were reviewed. All 25 children complained of nasal obstruction on presentation; other presenting symptoms included rhinorrhea (48%), snoring (36%), and mouth breathing (32%). All 25 patients were noted to have a mass in the nose on examination, and 16 (64%) also had a mass noted in the nasopharynx. All but 1 patient underwent surgical removal of the polyp: intranasal avulsion only, 2 patients; Caldwell-Luc procedures, 10 patients; intranasal procedures, 8 patients; and endoscopic procedures, 4 patients. Mean time to first recurrence was 44.5 months. Seven patients (29%) who underwent excision at our institution experienced recurrence, 3 after endoscopic procedures and 4 after intranasal procedures (with or without Caldwell-Luc; 1 of these patients had a second recurrence). Complications were unusual and included bleeding after pack removal (8.3%) and facial paresthesias (10%). Follow-up ranged from 2 days to almost 27 years and was aided by telephone interviews. We conclude that surgical treatment of these lesions is safe and effective. Endoscopic removal may result in a higher recurrence rate.

Open trial of methotrexate as treatment for autoimmune hearing loss.

OBJECTIVE: To assess the efficacy of low-dose methotrexate (MTX) administered for the treatment of autoimmune hearing loss. METHODS: This was a prospective, 12-month, open-label study of 17 patients with refractory autoimmune hearing loss. All patients had ongoing episodic worsening of hearing in one or both ears prior to enrollment despite traditional medical therapy. The MTX dose was 7.5-25 mg/week. Hearing loss and vertigo were evaluated at baseline and at completion of the study. Hearing improvement was defined as an improvement in pure tone threshold (PT) average of >10 dB or an increase in speech discrimination (SD) of >15%; worsening was defined as a decrease of >10 dB in PT or a decrease of >15% in SD in at least one ear. RESULTS: MTX was well tolerated. Among patients with Meniere's disease, 5 of 9 had improvement or resolution of vertigo. Equilibrium improved in all 3 patients with Cogan's syndrome and improved in 2 out of 3 patients with idiopathic hearing loss and this symptom. According to the parameters defined above, hearing improved in 11 patients (65%), was unchanged in 4 patients (23%), and worsened in 2 patients (12%). CONCLUSION: Long-term low-dose MTX therapy may be a useful therapy for at least some patients who have hearing loss with a presumptively autoimmune-mediated component that is refractory to traditional therapies.

Long-term follow-up of transtympanic gentamicin for Ménière's syndrome.

OBJECTIVE: Recent studies have shown that transtympanic gentamicin for Ménière's syndrome is effective. Current treatment protocols vary. One concept has been to perform a chemical ablation; the other has been to perform a chemical alteration. Ablation requires multiple injections and is effective in controlling the vertigo, but it is associated with a significant incidence of hearing loss. Chemical alteration uses a minimal dose to reduce vestibular function without affecting cochlear function. STUDY DESIGN: Prospective. SETTING: Tertiary medical center. PATIENTS: Patients had classic unilateral Ménière's syndrome that was unresponsive to medical therapy. INTERVENTION: A single injection of gentamicin is given, and the patient is seen 1 month after injection. If indicated, the patient receives another injection and is reevaluated 1 month later. MAIN OUTCOME MEASURES: Control of vertigo and maintenance of hearing using the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) guidelines (1995). RESULTS: Fifty-six patients have documented follow-up for 2 years or more, and 21 have 4 years or more of follow-up. This article presents the 4-year results as outlined by the AAO-HNS guidelines. Vertigo classes A and B were seen in 82% of patients. The patients followed 2 to 4 years had 86% vertigo class A and B results. Those followed 4 years or more show 76% with a vertigo class A or B result. In this study there has been minimal cochlear loss. There was vestibular change clinically, which was documented by electronystagmography. CONCLUSIONS: It appears that a single transtympanic gentamicin injection is effective in controlling the vertigo of Ménière's syndrome. Cochlear impact has been minimal. It is most useful for those patients who have failed medical management and are severely affected but not totally incapacitated by the disease.

Nocturnal oxygen enrichment of room air at 3800 meter altitude improves sleep architecture.

Sleep is known to be impaired at high altitude, and this may be a factor contributing to reduced work efficiency, general malaise, and the development of acute mountain sickness (AMS). Nocturnal room oxygen enrichment at 3800 m has been shown to reduce the time spent in periodic breathing and the number of apneas, to improve subjective quality of sleep, and to reduce the AMS score. The present study was designed to evaluate the effect of oxygen enrichment to 24% at 3800 m (lowering the equivalent altitude to 2800 m) on sleep architecture. Full polysomnography and actigraphy were performed on 12 subjects who ascended in 1 day to 3800 m and slept in a specially constructed room that allowed oxygen enrichment or ambient air conditions in a randomized, crossover, double-blind study. The results showed that subjects spent a significantly greater percentage of time in deep sleep (stages III and IV combined, or slow wave sleep) with oxygen enrichment versus ambient air (17.2 +/- 10.0% and 13.9 +/- 6.7%, respectively; p < 0.05 in paired analysis). No differences between treatments were seen with subjective assessments of sleep quality or with subject's assessment of the extent to which they suffered from AMS. This study provides further objective evidence of improved sleep as a result of oxygen enrichment at 3800 m and suggests that alleviating hypoxia may improve sleep quality.

Use of methotrexate for autoimmune hearing loss.

To assess the efficacy of low-dose methotrexate (MTX) given long-term for the treatment of autoimmune hearing loss, we performed a prospective open-label study of 11 patients with treatment-refractory autoimmune hearing loss. All patients had ongoing episodic worsening of hearing in 1 or both ears before enrollment despite traditional medical therapy. The MTX dose was 7.5 to 17.5 mg/wk. Hearing loss and vertigo were evaluated at baseline and at completion of the study. Hearing improvement was defined as an improvement in the pure tone threshold (PT) average of >10 dB or an increase in speech discrimination (SD) of >15%, whereas worsening was defined as a worsening of >10 dB in PT or a decrease of >15% in SD in at least 1 ear. The MTX was well tolerated. Among the 6 patients with Meniere's disease. 4 had improvement or resolution of vertigo, while 2 had no improvement. Disequilibrium improved in all 3 patients with Cogan's syndrome. According to the parameters defined above, hearing improved in 9 patients (82%), was unchanged in 1 patient (9%), and worsened in 1 patient (9%). Long-term low-dose MTX therapy may be a useful therapy for some patients who have hearing loss with a presumptively autoimmune-mediated component that is refractory to traditional therapies.

Evaluation of posttonsillectomy hemorrhage and risk factors.

BACKGROUND: A 13-year retrospective study was undertaken to determine the incidence of posttonsillectomy hemorrhage, to evaluate potential risk factors, and to assess the efficacy and safety of ambulatory tonsillectomy. METHODS: From January 1985 to December 1997, 4662 patients underwent tonsillectomy at our institution. Ninety patients with posttonsillectomy bleeding were identified. For each patient with posttonsillectomy bleeding, 2 nonbleeding control subjects were selected and matched by age and sex to evaluate potential risk factors. RESULTS: Age was the only factor found to be statistically significant among the bleeding patients and the control group. The highest incidence (3.61%) of posttonsillectomy hemorrhage occurred in patients 21 to 30 years of age. In our experience, secondary hemorrhage was more common than primary hemorrhage, presenting most frequently on postoperative days 5 to 7. CONCLUSIONS: The incidence of posttonsillectomy bleeding in this review was 1.93%, and about half (47%) of the patients with posttonsillectomy hemorrhage returned to the operating room for hemorrhage control. The highest incidence (3.61%) of posttonsillectomy hemorrhage occurred in patients 21 to 30 years of age. Patients with posttonsillectomy hemorrhage, regardless of management, had a 12% incidence of subsequent hemorrhage. We found no difference in the incidence of posttonsillectomy bleeding between outpatient and inpatient procedures.

Regulation of acetyl coenzyme A synthetase in Escherichia coli.

Cells of Escherichia coli growing on sugars that result in catabolite repression or amino acids that feed into glycolysis undergo a metabolic switch associated with the production and utilization of acetate. As they divide exponentially, these cells excrete acetate via the phosphotransacetylase-acetate kinase pathway. As they begin the transition to stationary phase, they instead resorb acetate, activate it to acetyl coenzyme A (acetyl-CoA) by means of the enzyme acetyl-CoA synthetase (Acs) and utilize it to generate energy and biosynthetic components via the tricarboxylic acid cycle and the glyoxylate shunt, respectively. Here, we present evidence that this switch occurs primarily through the induction of acs and that the timing and magnitude of this induction depend, in part, on the direct action of the carbon regulator cyclic AMP receptor protein (CRP) and the oxygen regulator FNR. It also depends, probably indirectly, upon the glyoxylate shunt repressor IclR, its activator FadR, and many enzymes involved in acetate metabolism. On the basis of these results, we propose that cells induce acs, and thus their ability to assimilate acetate, in response to rising cyclic AMP levels, falling oxygen partial pressure, and the flux of carbon through acetate-associated pathways.

The canalith repositioning procedure for the treatment of benign paroxysmal positional vertigo: a randomized controlled trial.

OBJECTIVE: To compare the canalith repositioning procedure (CRP) with a sham maneuver for the treatment of benign paroxysmal positional vertigo. PATIENTS AND METHODS: We recruited 50 patients with a history of positional vertigo and unilateral positional nystagmus on physical examination (Dix-Hallpike maneuver). Patients were randomized to either the CRP (n = 24) or a sham maneuver (n = 26). Measured outcomes included resolution of vertigo and positional nystagmus at follow-up examination. RESULTS: The mean duration of follow-up was 10 days for both groups. Resolution of symptoms was reported by 12 (50%) of the 24 patients in the CRP group and by 5 (19%) of the 26 patients in the sham group (P = .02). The results of the Dix-Hallpike maneuver were negative for positional nystagmus in 16 (67%) of 24 patients in the CRP group and in 10 (38%) of 26 patients in the sham group (P = .046). CONCLUSION: The CRP is effective treatment of benign paroxysmal positional vertigo, and this procedure can be performed by general internists on outpatients with this disorder.

Audiometric findings in patients with acoustic neuroma.

OBJECTIVE: Hearing loss remains the most common symptom associated with acoustic neuroma. This study documents the audiometric findings from 721 acoustic neuroma procedures. STUDY DESIGN: This was a retrospective study. The preoperative audiometric data were compiled and were analyzed by patient age, gender, tumor size, time of surgery, and neurofibromatosis Type 2 (NF 2). Postoperative audiometric data were arranged and compiled in the same way. The hearing classification proposed by the AAO-HNS was applied to all preoperative and postoperative cases. SETTING: Tertiary referral center. PATIENTS: Surgically confirmed acoustic neuroma patients who had not previously received surgical or radiosurgical therapy. Patients underwent surgery by the retrosigmoid approach. INTERVENTION: Surgical removal of an acoustic neuroma. MAIN OUTCOME RESULT: Provision of pure tone and speech data from a group of acoustic neuroma patients, including application of the recently introduced and accepted AAO-HNS hearing classification system. RESULTS: Preoperative audiometric data were obtained from 694 of 721 patients (96%), of whom 619 had measurable hearing. Postoperative audiometry was performed on 606 patients; 152 had usable data. The combined preoperative audiometric data revealed a high frequency sensorineural hearing loss. Word recognition was servicable. The postoperative pure tones and word recognition scores were worse than preoperative scores. Age, gender, tumor size, and time of surgery had some impact on the preoperative hearing and the postoperative result; NF 2 did not. CONCLUSIONS: The study confirms that hearing alteration is almost universal in acoustic neuroma patients. Hearing preservation is possible in a significant number of cases; however, the postoperative auditory function tends to be worse.

Acute cervical spine injuries: prospective MR imaging assessment at a level 1 trauma center.

PURPOSE: To determine the weighted average sensitivity of magnetic resonance (MR) imaging in the prospective detection of acute neck injury and to compare these findings with those of a comprehensive conventional radiographic assessment. MATERIALS AND METHODS: Conventional radiography and MR imaging were performed in 199 patients presenting to a level 1 trauma center with suspected cervical spine injury. Weighted sensitivities and specificities were calculated, and a weighted average across eight vertebral levels from C1 to T1 was formed. Fourteen parameters indicative of acute injury were tabulated. RESULTS: Fifty-eight patients had 172 acute cervical injuries. MR imaging depicted 136 (79%) acute abnormalities and conventional radiography depicted 39 (23%). For assessment of acute fractures, MR images (weighted average sensitivity, 43%; CI: 21%, 66%) were comparable to conventional radiographs (weighted average sensitivity, 48%; CI: 30%, 65%). MR imaging was superior to conventional radiography in the evaluation of pre- or paravertebral hemorrhage or edema, anterior or posterior longitudinal ligament injury, traumatic disk herniation, cord edema, and cord compression. Cord injuries were associated with cervical spine spondylosis (P < .05), acute fracture (P < .001), and canal stenosis (P < .001). CONCLUSION: MR imaging is more accurate than radiography in the detection of a wide spectrum of neck injuries, and further study is warranted of its potential effect on medical decision making, clinical outcome, and cost-effectiveness.

Assessment of dysequilibrium after acoustic neuroma removal.

OBJECTIVE: Published data evaluating the rate of dysequilibrium after acoustic neuroma removal are inconsistent. The purpose of this investigation was to determine the incidence and severity of dysequilibrium and quality of life in a group of patients after acoustic neuroma surgery. STUDY DESIGN: The study design was a retrospective chart review and survey that included demographic and medical history questions, the Dizziness Handicap Inventory (DHI), the UCLA Dizziness Questionnaire (UCLA-DQ), and the Health Status Questionnaire (HSQ). SETTING: The study was conducted in a multispecialty tertiary care clinic. PATIENTS: Two hundred thirty-seven subjects who underwent initial surgical removal of an acoustic neuroma between January 1990 and June 1997 were studied. MAIN OUTCOME MEASURES: Correlation of dysequilibrium with age, gender, and tumor size was measured. Survey analysis including DHI, UCLA-DQ, and HSQ scores. RESULTS: Sixty-five percent of patients reported persistent dysequilibrium after surgery. A majority of those with dysequilibrium had DHI, UCLA-DQ, and HSQ scores that suggested minimal impact on the quality of life. The HSQ scores were statistically significantly poorer for the patients with dysequilibrium than for those without dysequilibrium. CONCLUSIONS: Sixty-five percent of patients reported dysequilibrium after acoustic neuroma removal. The quality-of-life impact was mild.