Local-scale Arctic tundra heterogeneity affects regional-scale carbon dynamics.

In northern Alaska nearly 65% of the terrestrial surface is composed of polygonal ground, where geomorphic tundra landforms disproportionately influence carbon and nutrient cycling over fine spatial scales. Process-based biogeochemical models used for local to Pan-Arctic projections of ecological responses to climate change typically operate at coarse-scales (1km2-0.5°) at which fine-scale (<1km2) tundra heterogeneity is often aggregated to the dominant land cover unit. Here, we evaluate the importance of tundra heterogeneity for representing soil carbon dynamics at fine to coarse spatial scales. We leveraged the legacy of data collected near Utqiagvik, Alaska between 1973 and 2016 for model initiation, parameterization, and validation. Simulation uncertainty increased with a reduced representation of tundra heterogeneity and coarsening of spatial scale. Hierarchical cluster analysis of an ensemble of 21st-century simulations reveals that a minimum of two tundra landforms (dry and wet) and a maximum of 4km2 spatial scale is necessary for minimizing uncertainties (<10%) in regional to Pan-Arctic modeling applications.

Efficacy of lumiracoxib in osteoarthritis: a review of nine studies.

Lumiracoxib is a cyclooxygenase-2 selective inhibitor in development for the treatment of osteoarthritis (OA), rheumatoid arthritis and acute pain. We reviewed nine clinical studies of 1-52 weeks' duration demonstrating the efficacy of lumiracoxib in OA. Male and female patients aged > or = 18 years with primary OA of the hand, hip or knee received lumiracoxib, placebo or active comparators (diclofenac, celecoxib or rofecoxib). Lumiracoxib provided consistent reductions in OA pain intensity and improvements in the patient's global assessment of disease activity and functional status (assessed using the Western Ontario and McMaster Universities Osteoarthritis Index questionnaire or the Australian/Canadian OA Hand Index). These results were superior to placebo and similar to the active comparators tested. In addition, lumiracoxib was consistently superior to placebo and generally similar to active comparators in terms of the new Outcome Measures in Clinical Trials and Osteoarthritis Research Society International criteria. These were used to provide a single measure of response to treatment, taking into account pain, the patient's global assessment of disease activity and functional status.

Zidovudine therapy in an inner city population.

To determine the compliance and tolerance with zidovudine (azidothymidine or AZT) therapy among poor, minority, and intravenous drug-using patients, data were collected on all AIDS and ARC patients followed for at least 4 weeks in a New York City Human Immunodeficiency Virus clinic. Ninety-nine patients received zidovudine, of whom 75% were males, 92% were minorities, and 59% had a history of intravenous drug use. Of the 99 patients, 72 had AIDS and 27 had ARC with T-helper (CD4) lymphocytes less than or equal to 500 mm3. Eighty-seven of the 99 patients (88%) were compliant with zidovudine therapy. Fifty-seven percent of these had at least one adverse drug reaction requiring dose reduction (44%) or cessation (13%). Adverse reactions were similar to those reported in other populations with HIV-related illness, although headache and nausea were less common. Twenty opportunistic infections (OIs) or HIV-related malignancies occurred in 15 of 82 (18%) patients who were on zidovudine for at least 4 weeks (7.6 OIs/1,000 patient weeks). Seven of the 82 died (9%), compared to 9 of the 17 patients (53%) who did not complete 4 weeks of zidovudine therapy (p less than 0.05). There were no significant differences in any of these measures when intravenous drug users were compared with other risk groups. We conclude that zidovudine can be administered to intravenous drug users and others in an inner city clinic with acceptable compliance and tolerance.

Secondary structure composition and pH-dependent conformational changes of soluble recombinant HLA-DM.

HLA-DM catalyzes the release of invariant chain fragments from newly synthesized major histocompatibility complex (MHC) class II molecules, stabilizes empty class II molecules, and edits class II-associated peptides by preferentially releasing those that are loosely bound. The ability of HLA-DM to carry out these functions in vitro is pH dependent, with an optimum at pH 4.5-5.5 and poor activity at pH 7. The structural basis for these properties of HLA-DM is unknown. Sequence homology suggests that HLA-DM resembles classical, peptide-binding MHC class II molecules. In this study, we examined whether HLA-DM has a secondary structure composition consistent with an MHC fold and whether HLA-DM changes conformation between pH 5 and pH 7. Far-UV circular dichroism (CD) spectra of recombinant soluble HLA-DM (sDM) indicate that HLA-DM belongs to the alpha/beta class of proteins and structurally resembles both MHC class I and class II molecules. The CD peak around 198 nm increases upon going from neutral to endosomal pH and drops sharply upon denaturation below pH 3.5, distinguishing at least three states of sDM: the denatured state and two highly similar folded states. Fluorescence emission spectra show a slight blue-shift and a approximately 20% drop in intensity at pH 5 compared with pH 7. Unfolding experiments using guanidinium chloride show that the stability of sDM is somewhat reduced but not lost at pH 5. These results indicate that sDM undergoes a pH-dependent conformational change between neutral and endosomal pH. The change seems to involve both hydrogen bonding patterns and the hydrophobic core of sDM and may contribute to the pH dependence of DM activity.

Efficacy, safety and tolerability of lumiracoxib in patients with rheumatoid arthritis.

A randomised, double-blind study was performed to assess the efficacy and tolerability of lumiracoxib in patients with rheumatoid arthritis (RA). Patients received lumiracoxib 200mg once daily (o.d.) (n= 280), lumiracoxib 400mg o.d. (n= 281), naproxen 500 mg twice daily (n= 279) or placebo (n= 284) for 26 weeks. The primary efficacy variable was response to treatment according to ACR20 criteria (adjusted for prohibited concomitant or excessive rescue medication use and discontinuations due to unsatisfactory therapeutic response) at week 13. Safety and tolerability was also assessed. Significantly more patients receiving lumiracoxib than placebo were responders according to ACR20 criteria at week 13 (41.1 and 42.7% for lumiracoxib 200 and 400 mg o.d., respectively; 32.4% for placebo; both p < 0.05). The proportion responding to naproxen (39.1%) was not significantly different from placebo. Prespecified gastrointestinal adverse events were more frequent with naproxen than with either lumiracoxib dose or placebo. Lumiracoxib is therefore an effective and well-tolerated therapy for RA.

Mediation by HLA-DM of dissociation of peptides from HLA-DR.

Human leukocyte antigen (HLA)-DM is an unconventional major histocompatibility complex (MHC) class II heterodimer that is important for B-cell-mediated antigen processing and presentation to MHC class II-restricted T cells. HLA-DM is encoded by two genes, DMA and DMB, which map to the MHC class II region, and shares some homology with MHC class I and class II proteins. Here we define the biochemical role of HLA-DM. Recombinant soluble HLA-DM heterodimers have been purified from culture supernatants of insect cell transformants. At pH 5.0, they induce the dissociation of a subset of peptides bound to HLA-DR, including a nested set of class-II-associated invariant chain peptides (CLIP). This process liberates HLA-DR and leads to the enhanced binding of exogenous peptides.

The longitudinal use of the Global Assessment Scale in multiple-rater situations.

The Global Assessment Scale was used by multiple clinicians to rate 108 chronically mentally ill outpatients for 18 months. With prior training, high interrater reliability was obtained. Analysis suggests that fluctuations in patients' scores were not attributable to measurement error due to the sequential ratings of multiple clinicians. Moreover, GAS means were inversely correlated with decompensations over the study period. Results indicate that the DMS-III-R recommended use of the GAS in multiple-rater outpatient facilities can be both reliable and clinically useful when supported by thorough staff training.