Spatial dynamics of the invasive defoliator amber-marked birch leafminer across the Anchorage landscape.

The amber-marked birch leafminer (Profenusa thomsoni [Konow]) (Hymenoptera: Tenthredinidae) has caused severe infestations of birch species in Anchorage, AK, since 2002. Its spatial distribution has been monitored since 2006 and summarized using interpolated surfaces based on simple kriging. Results indicate that this insect pest is unevenly distributed, occurring in multineighborhood sized patches that migrate from year to year. Patches showing heavy infestation one year are followed by light infestations the following year. In this study, we developed methods of assessing and describing spatial distributions of P. thomsoni as they vary from year to year, and speculate on potential causes of these trends in landscape patterns.

Resistance to alpha/beta interferons correlates with the epizootic and virulence potential of Venezuelan equine encephalitis viruses and is determined by the 5' noncoding region and glycoproteins.

We compared the alpha/beta interferon (IFN-alpha/beta) sensitivities of the TC-83 vaccine strain and 24 enzootic and epizootic Venezuelan equine encephalitis (VEE) isolates. The IFN-resistant or -sensitive phenotype correlated well with epizootic or enzootic potential. IFN-alpha/beta resistance of Trinidad donkey (TRD) virus correlated with virulence determinants in the 5' noncoding region and glycoproteins. Infection of mice lacking a functional IFN system with the IFN-sensitive TC-83 virus resulted in disease equivalent to that produced by the virulent, IFN-resistant TRD virus, further demonstrating that IFN resistance contributes to VEE virus virulence and is a biological marker of epizootic potential.

Netilmicin sulfate: a comparative evaluation of antimicrobial activity, pharmacokinetics, adverse reactions and clinical efficacy.

Netilmicin, the 1-N-ethyl derivative of sisomicin, is a new aminoglycoside antibiotic that was recently marketed in the United States. Its role in therapeutics is not yet established. The pharmacokinetic profile of netilmicin is very similar to that of gentamicin. Its antimicrobial spectrum and clinical efficacy is similar to that of gentamicin, tobramycin and amikacin. It is less active in vitro against Pseudomonas aeruginosa that gentamicin and tobramycin, but in clinical trials the efficacy of netilmicin against the organism has been similar to other aminoglycosides. Netilmicin is active against some gentamicin and tobramycin-resistant strains of gram-negative bacilli, particularly those harboring adenylating and phosphorylation enzymes. Most of these strains are sensitive to amikacin as well, and amikacin is also active against most netilmicin-resistant strains of these bacteria. Therefore, amikacin remains the aminoglycoside of choice against gentamicin tobramycin and netilmicin-resistant gram-negative bacilli. In comparison to other currently available aminoglycosides, a lower frequency of nephrotoxicity and ototoxicity has been observed in laboratory animals given netilmicin. This has not been unequivocally demonstrated in humans. The frequency of nephrotoxicity in humans has been similar to that of other aminoglycosides. The frequency of ototoxicity associated with netilmicin in humans has been low but not significantly less than in other aminoglycosides, except in one trial. If further studies document a significantly lower frequency of ototoxicity with netilmicin, it may become the aminoglycoside of choice for patients with significant risk factors for ototoxicity, such as advanced age, renal impairment, concomitant ototoxic drug therapy and prolonged aminoglycoside administration.

Infectious mononucleosis in the athlete. Diagnosis, complications, and management.

Although almost always a benign, self-limiting disease, infectious mononucleosis accounts for considerable symptomatic illness in the young athlete and can, on occasion, be truly life-threatening. Recognition of the syndrome "glandular fever," vis-a-vis infectious mononucleosis--fever, pharyngitis, lymphadenopathy, and splenomegaly, with characteristic changes in the peripheral blood leukocytes--dates back over a half a century. However, seroepidemiologic studies have only recently established its viral causation and epidemiology. This acute infection by the Epstein-Barr virus is unique pathophysiologically--an acute, self-limiting, lymphoproliferative disorder with autoimmune features--and may well be the cause or one of the causes of several malignant neoplasms, Burkitt's lymphoma, and nasopharyngeal carcinoma. This review (1) describes infectious mononucleosis, pathophysiologically, clinically, and epidemiologically; and outlines its most frequent and serious complications; (2) discusses how to reliably diagnose infectious mononucleosis and evaluate the heterophile-negative case; and (3) addresses management, especially the thorny issues of the use of corticosteroids and restriction from athletic training and participation.

New instrument for rapid determination of activities of lactate dehydrogenase isoenzymes.

Lactate dehydrogenase isoenzymes can be distinguished kinetically by the fact that isoenzyme H is strongly inhibited a few seconds after the reaction is started if high concentrations of pyruvate are present, in contrast to the M isoenzyme. A new instrument that exploits this fact can measure both the total activity and the proportion of H isoenzyme in serum or plasma in 8 to 10 s. The instrument consists of a simplified stopped-flow apparatus in which the plasma is assayed for lactate dehydrogenase activity, and an electronic device that measures the rate of the reaction at two pre-set time intervals. The first rate is taken between 0.2 and 0.4 s after the reaction is started, a time at which both isoenzymes are fully active, and at which the rate obtained thus reflects total lactate dehydrogenase activity in the plasma sample. The second rate is measured 4 to 6 s after the start of the reaction, at which time the H isoenzyme has become inhibited and the observed rate compared to the initial rate is therefore proportional to the percentage of H isoenzyme activity in the serum. These two rates are electronically displayed on two three-digit voltmeters, the first display being the total activity, the second a number proportional to the inhibited slope. The percentage of M isoenzyme can then be calculated from the initial and final rate. A total of five to six repeat assays may be done within a minute on 1 ml of plasma or serum. This instrument may be of significant value in following the progress of myocardial infarctions and other diseases.