Publications

CONTEXT

Heterozygous mutations in the melanocortin-4 receptor (MC4R) gene are the most common monogenic form of severe obesity in children. There are conflicting reports regarding the prevalence, nature, and pathogenic effects of MC4R mutations in adults with severe late-onset obesity.

OBJECTIVE

Our objective was to determine the prevalence of MC4R mutations in a cohort of severely obese adults and to determine the clinical phenotype and the phenotype-genotype relationship within adult MC4R mutation carriers.

DESIGN AND SETTING

We conducted an observational study at a referral center.

PATIENTS OR OTHER PARTICIPANTS

Participants included 769 adult patients with body mass index of at least 35 kg/m(2) and 444 nonobese control individuals.

INTERVENTIONS

There were no interventions.

MAIN OUTCOME MEASURES

We assessed the prevalence of pathogenic MC4R mutations, functional characteristics of the detected mutations, phenotype, and phenotype-genotype relationship within mutation carriers.

RESULTS

The global prevalence of obesity-specific MC4R mutations was 2.6%, and the 95% confidence interval (CI(95)) was 1.5-3.7. The prevalence of MC4R mutations was similar in patients developing obesity in childhood (2.83%; CI(95), 0.9-4.8) and in patients with a later onset of the disease (2.35%; CI(95), 0.9-3.8). Adult obese MC4R mutation carriers did not present with binge eating or with any specific clinical phenotype. The severity of the functional alterations of the mutated MC4Rs and in particular the intracellular retention of the receptor correlates both with the severity and the onset of the obesity in the mutation carriers.

CONCLUSIONS

Obese adult carriers of functionally relevant MC4R mutations do not specifically present with binge-eating disorder or a history of early-onset obesity. The onset and severity of the obesity in the carriers is related to the functional severity of the MC4R mutations.

The aim of the study was to investigate the impact of ischemia/reperfusion injury on the proteome of Kupffer cells. Lean Zucker rats (n = 6 each group) were randomized to 75 min of warm ischemia or sham operation. After reperfusion for 8 h, Kupffer cells were isolated by enzymatic perfusion and density gradient centrifugation. Proteins were tryptically digested into peptides and differentially labeled with iTRAQ (isobaric tags for relative and absolute quantitation) reagent. After fractionation by cation exchange chromatography, peptides were identified by mass spectrometry (ESI-LC-MS/MS). Spectra were interrogated against the Swiss-Prot database and quantified using ProteinProspector. The results for heat shock protein 70 and myeloperoxidase were validated by ELISA. Quantitative information for more than 1559 proteins was obtained. In the ischemia group proteins involved in inflammation were significantly up-regulated. The ratio for calgranulin B in the ischemia/sham group was 1.81 +/- 0.97 (p < 0.0001), for complement C3 the ratio was 1.81 +/- 0.49 (p < 0.0001), and for myeloperoxidase the ratio was 1.30 +/- 0.32. Myeloperoxidase was only recently documented in Kupffer cells. The antioxidative proteins Cu,Zn-superoxide dismutase (1.34 +/- 0.19; p < 0.001) and catalase (1.23 +/- 0.43; p < 0.001) were also elevated. In conclusion, ischemia/reperfusion injury induces alterations in the Kupffer cell proteome. Isotope ratio mass spectrometry is a powerful tool to investigate these reactions. The ability to simultaneously monitor several pathways involved in reperfusion stress may result in important mechanistic insight and possibly new treatment options.

BACKGROUND

Cyclooxygenase-2 (COX-2) inhibitors were widely prescribed in the years following their introduction, but little is known about the frequency and context of their use across different age groups.

OBJECTIVE

To determine patterns and context of COX-2 inhibitor use in younger and older adults.

DESIGN

Cross-sectional surveys conducted each year from 1998 to 2002.

PARTICIPANTS

National Ambulatory Medical Care survey, a nationally representative sample of patient visits to community-based outpatient practices.

MEASUREMENTS

New or preexisting medication use recorded at the patient visit.

RESULTS

Cyclooxygenase-2 inhibitor use rose rapidly in all age groups, particularly in elders. By 2002, COX-2 inhibitors accounted for 67% of recorded nonsteroidal anti-inflammatory drug (NSAID) uses in visits by patients age 65 and older, compared with 33% of NSAID uses in adults age 18 to 44 and 54% in adults age 45 to 64 (P<.001). Coadministration of proton pump inhibitors or misoprostol with NSAIDs was low throughout the study period in all age groups, ranging from 6.7% of all NSAID users in 1998 (the year before COX-2 inhibitors were introduced) to 8.2% in 2002 (P=.68). For both older and younger adults, use of these gastroprotective agents occurred at similar rates among persons taking COX-2 inhibitors compared with those taking nonselective NSAIDs. Among elderly NSAID users in 2001 to 2002, elders with cardiovascular disease were more likely to receive COX-2 inhibitors than those without cardiovascular disease (86% vs 66%, P<.001).

CONCLUSIONS

Cyclooxygenase-2 inhibitors were rapidly adopted among all age groups, but particularly among the elderly, where use in patients with cardiovascular disease was especially high. Use of these agents largely supplemented, rather than replaced, older forms of gastroprotective therapy. The rapid and widespread use of COX-2 inhibitors in spite of their higher cost and potential for complications provides important lessons for physicians' approach to new and highly promoted drugs.

The critical regulator of polarity, Par6, is a key member of a multi-component polarity complex that controls a variety of cellular processes such as asymmetric cell division, establishment of epithelial apico-basal polarity, and polarized cell migration. Recently, we have come to understand how regulation of the Par6 interactome by extracellular cues such as integrin and transforming growth factor beta signalling regulates cell motility and tight junction dissolution. These studies have begun to elucidate how signalling to the polarity complex might regulate pathological processes such as tumour cell invasion and metastasis.

BACKGROUND

Chromosome four of Drosophila melanogaster, known as the dot chromosome, is largely heterochromatic, as shown by immunofluorescent staining with antibodies to heterochromatin protein 1 (HP1) and histone H3K9me. In contrast, the absence of HP1 and H3K9me from the dot chromosome in D. virilis suggests that this region is euchromatic. D. virilis diverged from D. melanogaster 40 to 60 million years ago.

RESULTS

Here we describe finished sequencing and analysis of 11 fosmids hybridizing to the dot chromosome of D. virilis (372,650 base-pairs) and seven fosmids from major euchromatic chromosome arms (273,110 base-pairs). Most genes from the dot chromosome of D. melanogaster remain on the dot chromosome in D. virilis, but many inversions have occurred. The dot chromosomes of both species are similar to the major chromosome arms in gene density and coding density, but the dot chromosome genes of both species have larger introns. The D. virilis dot chromosome fosmids have a high repeat density (22.8%), similar to homologous regions of D. melanogaster (26.5%). There are, however, major differences in the representation of repetitive elements. Remnants of DNA transposons make up only 6.3% of the D. virilis dot chromosome fosmids, but 18.4% of the homologous regions from D. melanogaster; DINE-1 and 1360 elements are particularly enriched in D. melanogaster. Euchromatic domains on the major chromosomes in both species have very few DNA transposons (less than 0.4 %).

CONCLUSION

Combining these results with recent findings about RNAi, we suggest that specific repetitive elements, as well as density, play a role in determining higher-order chromatin packaging.