Discovery of a pathway for terminal-alkyne amino acid biosynthesis.

Living systems can generate an enormous range of cellular functions, from mechanical infrastructure and signalling networks to enzymatic catalysis and information storage, using a notably limited set of chemical functional groups. This observation is especially notable when compared to the breadth of functional groups used as the basis for similar functions in synthetically derived small molecules and materials. The relatively small cross-section between biological and synthetic reactivity space forms the foundation for the development of bioorthogonal chemistry, in which the absence of a pair of reactive functional groups within the cell allows for a selective in situ reaction1-4. However, biologically 'rare' functional groups, such as the fluoro5, chloro6,7, bromo7,8, phosphonate9, enediyne10,11, cyano12, diazo13, alkene14 and alkyne15-17 groups, continue to be discovered in natural products made by plants, fungi and microorganisms, which offers a potential route to genetically encode the endogenous biosynthesis of bioorthogonal reagents within living organisms. In particular, the terminal alkyne has found broad utility via the Cu(I)-catalysed azide-alkyne cycloaddition 'click' reaction18. Here we report the discovery and characterization of a unique pathway to produce a terminal alkyne-containing amino acid in the bacterium Streptomyces cattleya. We found that L-lysine undergoes an unexpected reaction sequence that includes halogenation, oxidative C-C bond cleavage and triple bond formation through a putative allene intermediate. This pathway offers the potential for de novo cellular production of halo-, alkene- and alkyne-labelled proteins and natural products from glucose for a variety of downstream applications.

Telepathology for intraoperative consultations and expert opinions: the experience of the Eastern Québec Telepathology Network.

CONTEXT: The Eastern Québec Telepathology Network was created to provide uniform diagnostic telepathology services in a huge territory with a low population density. OBJECTIVES: To evaluate the diagnostic concordance and turnaround times of intraoperative consultations (IOCs) and the turnaround time of expert opinions by telepathology. DESIGN: For the IOC part of the study, the first 104 IOC diagnoses from a single hospital were compared with those in the final pathology report. The turnaround time of the IOC was calculated from the arrival of the specimen at the pathology laboratory until the time of the call to the surgeon. For the expert opinion part of this study, the first 94 expert opinions from 5 hospitals were reviewed by comparing the time of the initial request until the time of the final report. RESULTS: Of the 104 cases in the IOC study, 8 diagnoses (7.7%) were slightly discrepant because of differences in terminology but remained in the same category of interpretation. Two cases (1.9%) were significantly discordant. Therefore, 102 cases (98.1%) were either concordant or had no clinically significant discrepancies. The average turnaround time for IOCs was 20 minutes (range, 8-43). For the expert opinion part of the study, reports were signed out within 24 hours in 64 cases (68%) and within 72 hours in 80 cases (85.1%). CONCLUSIONS: The Eastern Québec Telepathology Network allows a rapid, high-quality IOC service to be maintained for a hospital where no pathologist was available on site. It also provides a fast, expert opinion service to pathologists working alone.

Development of a multiplex microsphere immunoassay for the quantitation of salivary antibody responses to selected waterborne pathogens.

Saliva has an important advantage over serum as a medium for antibody detection due to non-invasive sampling, which is critical for community-based epidemiological surveys. The development of a Luminex multiplex immunoassay for measurement of salivary IgG and IgA responses to potentially waterborne pathogens, Helicobacter pylori, Toxoplasma gondii, Cryptosporidium, and four noroviruses, involved selection of antigens and optimization of antigen coupling to Luminex microspheres. Coupling confirmation was conducted using antigen specific antibody or control sera at serial dilutions. Dose-response curves corresponding to different coupling conditions were compared using statistical tests. Control proteins in the specific antibody assay and a separate duplex assay for total immunoglobulins G and A were employed to assess antibody cross-reactivity and variability in saliva composition. 200 saliva samples prospectively collected from 20 adult volunteers and 10 paired sera from a subset of these volunteers were used to test this method. For chronic infections, H. pylori and T. gondii, individuals who tested IgG seropositive using commercial diagnostic ELISA also had the strongest salivary antibody responses in salivary antibody tests. A steep increase in anti-norovirus salivary antibody response (immunoconversion) was observed after an episode of acute diarrhea and vomiting in a volunteer. The Luminex assay also detected seroconversions to Cryptosporidium using control sera from infected children. Ongoing efforts involve further verification of salivary antibody tests and their application in larger pilot community studies.

[Results of measuring neutron dose inside the Russian segment of the International Space Station using bubble detectors in experiment Matreshka-R].

Distribution of neutron equivalent dose both inside and outside the spherical phantom (experiment Matryeshka-R) was determined with the help of dedicated research equipment "Bubble-dosimeter". Equipment is built up from an automatic bubbles counter and 8 bubble detectors of neutrons with energy ranging from approximately 200 keV to 15 MeV. Measurements inside the ISS were made in several 7-day sessions in the period from April 2006 till October 2007 (ISS increments 13-15). According to the bubble detectors on the outside of the phantom, ambient neutron dose H*(10) was equal to 0.1 mSv/d or approximately 20% of the dose from charged particles inside the ISS. In the tissue-equivalent phantom, neutron dose was 1.2 +/- 0.2 times less as compared with the phantom surface which characterized the degree of dose attenuation in cosmonaut's body.

Rhodococcus equi infections in immunocompetent hosts: case report and review.

Rhodococcus equi is an unusual cause of infection in humans. Infection in immunocompetent patients is extremely rare-only 19 cases in immunocompetent hosts have been reported. Localized infections represent nearly 50% of reported cases. Pulmonary infections account for only 42% of infections in immunocompetent hosts, compared with 84% of infections in immunocompromised hosts. The mortality rate among immunocompetent patients is approximately 11%, compared with rates of 50%-55% among human immunodeficiency virus (HIV)-infected patients and 20%-25% among non-HIV-infected immunocompromised patients. Treatment of infections in immunocompetent hosts depends on the site of infection. Serious infections need to be treated with combinations of parenteral antibiotics, followed by combinations of oral antibiotics. Surgical treatment is necessary for certain types of local infections. We report a pulmonary infection due to R. equi in an immunocompetent patient, and we review all reported cases of R. equi infection in immunocompetent hosts.

The timing of surgical alignment for congenital (infantile) esotropia.

At this time, the beneficial effect of accurate alignment by age 2 in congenital esotropia has been well established by clinical and laboratory studies. There is, however, only scanty clinical evidence that alignment before age 1, much less before 6 months of age, may yield a better quality of binocularity (i.e., refined stereoacuity) than alignment by age 2. Pitfalls of very early alignment are present. In addition, the ophthalmologist must be vigilant in following the initially aligned patient and be ready to treat vertical motor defects, amblyopia, and acquired refractive errors. The need for additional horizontal surgery after initial alignment is also common. The optimum result in the surgical treatment of congenital esotropia generally shows binocularity that is within the confines of a monofixation syndrome, and refined stereoacuity remains an elusive target and a rare outcome, no matter at what age the alignment is achieved.

Outcome study of bilateral lateral rectus recession for intermittent exotropia in children.

BACKGROUND AND OBJECTIVE: The purpose of this paper is to report a statistical analysis of the surgical results in a consecutive series of 52 children treated by bilateral lateral rectus recession for intermittent exotropia when the operating surgeon was confronted by an increase in manifestation of the strabismus. PATIENTS AND METHODS: The charts were abstracted for age at initial surgery, quantity of initial deviation, initial refraction, motor alignment at one week, six months, and at the end of the study. The incidence and result of secondary surgery and the incidence of the monofixation syndrome result was also determined. RESULTS: Thirty-two (62%) of the patients were successfully aligned at six months by the initial surgery performed for a mean of 25 prism diopters (PD) of preoperative deviation at a mean age of 4 years 8 months. Eleven patients (21%) were undercorrected and 9 patients (17%) were overcorrected at the six month exam. The patients were followed for a mean of 4 years, 4 months. Alignment at 6 months postoperatively was predictive of success by the end of the study, but the age at initial surgery, the size of the deviation, esotropia at 1 week, and initial refraction were not predictive of success. Secondary surgery was performed in 11 patients and the monofixation syndrome result was found in 5 patients. CONCLUSION: Successful alignment was achieved in the majority of children treated by an initial bilateral lateral rectus recession utilizing a currently popular surgical dosage table. Long term alignment success was not predicted by esotropia during the first postoperative week or the age at initial surgery but was correlated with the 6-month data. Secondary surgery was performed in 20% and the incidence of the monofixation syndrome was approximately 10% at the end of the study.

Surfing-related ocular injuries.

PURPOSE: This report evaluates the clinical characteristics of surfing-related ocular trauma to learn the nature of such injuries and propose possible preventive measures. METHODS: The authors reviewed 11 cases of surfing-related eye injuries caused by direct trauma from the surfboard, studying their mechanism of injury, the associated ocular complications, and the anatomic and visual outcomes of surgical repair. RESULTS: Surfing-related ocular injuries occurred exclusively in young males (mean age, 24.8 years; range, 14-37 years). The mechanism of injury most frequently responsible was impact with the sharp nose of the surfboard following a fall. Serious posterior segment complications were observed in all 11 patients, with nine patients suffering ruptured globes. Despite immediate medical attention, five patients did not recover ambulatory levels of visual acuity (>5/200). CONCLUSIONS: Surfing-related ocular trauma presenting to the retinal specialist typically leaves the patient with a permanent visual disability. Important factors contributing to these high-velocity injuries include the sharply pointed nose of the surfboard and the leash keeping the surfer in close proximity to the board following a fall. A simple modification in surfboard design such as blunting the sharp nose of the surfboard, or appropriate protective guards fitted over the surfboard nose, should lessen the severity of such injuries.

Human coenurosis in North America: case reports and review.

Coenurosis is a zoonotic disease of humans caused by the larval stage of Taenia (Multiceps) species. In North America, the adult tapeworm of Taenia (Multiceps) serialis is found in canids. The cystic larval forms (coenuri) are found in hares, rabbits, squirrels, and, rarely, in humans. We review in clinical detail the fifth case reported from North America, involving a child with extensive central nervous system involvement. We also report a sixth case, involving an adult with an intramuscular coenurus. The latter case was diagnosed by needle aspiration of the cyst. Although praziquantel administration may have been effective in killing the parasite in both patients, we are concerned about the production of marked inflammation as a result of treatment. The four other North American cases are reviewed, and the epidemiology of the infection in animals is discussed.

Efficacy of trovafloxacin, a new quinolone antibiotic, in experimental staphylococcal endocarditis due to oxacillin-resistant strains.

Therapeutic options for severe infections caused by strains of oxacillin-resistant Staphylococcus aureus (ORSA) and coagulase-negative staphylococci (ORSE) are very limited. With the increasing resistance of such strains to aminoglycosides, rifampin, and currently available quinolone agents, as well as the recent documentation of increasing resistance of ORSA to vancomycin (VANCO), new treatment alternatives are imperative. The in vivo efficacy of trovafloxacin (TROVA), a new quinolone agent with excellent antistaphylococcal activity in vitro, against experimental endocarditis (IE) due to beta-lactamase-producing ORSA and ORSE strains (ORSA and ORSE IE) was evaluated. TROVA (25 mg/kg of body weight intravenously [i.v.] twice daily [b.i.d]) was compared to VANCO (20 mg/kg i.v. b.i.d.) and two regimens of ampicillin-sulbactam (AMP-SUL; 200 mg/kg intramuscularly [i.m.] three times a day [t.i.d.] and 20 mg/kg i.m. b.i.d.), with all agents given for 3 or 6 days. AMP-SUL was included as a comparative treatment regimen because of its proven efficacy against experimental ORSA and ORSE IE. For both ORSA and ORSE IE, TROVA, AMP-SUL, and VANCO each reduced staphylococcal densities in vegetations compared to untreated controls (P < 0.01). For ORSA IE, TROVA was the most rapidly bactericidal agent--although not to a statistically significant degree--correlating with its superior bactericidal effect in vitro compared to those of VANCO and AMP-SUL.

Outcome study of bilateral lateral rectus recession for intermittent exotropia in children.

PURPOSE: This paper reports an outcome study of 52 consecutive children treated by bilateral lateral rectus recession for intermittent exotropia over a 9 year period (1981-90) with a minimum follow up of 6 months. METHODS: Successful alignment was defined as the absence of any postoperative intermittent or constant tropia in any position of gaze. The study examined the variables that might be predictive of successful alignment. The charts were abstracted for age at initial surgery, quantity of initial deviation, initial refraction, motor alignment at 1 week and 6 months, final alignment, secondary surgery results and the incidence of a monofixation syndrome result. RESULTS: Motor tests demonstrated that 32 (62%) of the patients were successfully aligned by the initial procedure performed for a mean of 25 prism diopters of preoperative deviation while viewing distant targets at a mean age of 4 years 8 months, followed for a mean of 4 years, 4 months. The incidence of undercorrections and overcorrections were approximately equal in quantity suggesting that the current surgical dosage was adequate, but the age at initial surgery, initial deviation, initial refraction and 1 week postoperative alignment results were not predictive of success. Alignment at 6 months, however, was highly correlated with successful alignment by the end of the study (p = 0.002). Secondary surgery was performed for 11 patients and 5 patients were found to have a monofixation syndrome result. CONCLUSION: Successful alignment was achieved in the majority of children treated for intermittent exotropia by an initial bilateral lateral rectus recession. However, 20% of the patients received secondary surgery for a residual deviation, and the study confirmed a previously reported 10% incidence of monofixation syndrome result in children surgically treated for this type of strabismus.