Publications

The bacterium Helicobacter pylori is remarkable for its ability to persist in the human stomach for decades without provoking sterilizing immunity. Since repetitive DNA can facilitate adaptive genomic flexibility via increased recombination, insertion, and deletion, we searched the genomes of two H. pylori strains for nucleotide repeats. We discovered a family of genes with extensive repetitive DNA that we have termed the H. pylori RD gene family. Each gene of this family is composed of a conserved 3' region, a variable mid-region encoding 7 and 11 amino acid repeats, and a 5' region containing one of two possible alleles. Analysis of five complete genome sequences and PCR genotyping of 42 H. pylori strains revealed extensive variation between strains in the number, location, and arrangement of RD genes. Furthermore, examination of multiple strains isolated from a single subject's stomach revealed intrahost variation in repeat number and composition. Despite prior evidence that the protein products of this gene family are expressed at the bacterial cell surface, enzyme-linked immunosorbent assay and immunoblot studies revealed no consistent seroreactivity to a recombinant RD protein by H. pylori-positive hosts. The pattern of repeats uncovered in the RD gene family appears to reflect slipped-strand mispairing or domain duplication, allowing for redundancy and subsequent diversity in genotype and phenotype. This novel family of hypervariable genes with conserved, repetitive, and allelic domains may represent an important locus for understanding H. pylori persistence in its natural host.

BACKGROUND

Cardiovascular disease (CVD) is an increasing cause of morbidity and mortality in HIV-infected patients. However, it is controversial whether HIV infection contributes to accelerated atherosclerosis independent of traditional CVD risk factors.

METHODS

Cross-sectional study of HIV-infected participants and controls without pre-existing CVD from the study of Fat Redistribution and Metabolic Change in HIV Infection (FRAM) and the Multi-Ethnic Study of Atherosclerosis (MESA). Preclinical atherosclerosis was assessed by carotid intima-medial thickness (cIMT) measurements in the internal/bulb and common regions in HIV-infected participants and controls after adjusting for traditional CVD risk factors.

RESULTS

For internal carotid, mean IMT was 1.17 +/- 0.50 mm for HIV-infected participants and 1.06 +/- 0.58 mm for controls (P < 0.0001). After multivariable adjustment for demographic characteristics, the mean difference of HIV-infected participants vs. controls was 0.188 mm [95% confidence interval (CI) 0.113-0.263, P < 0.0001]. Further adjustment for traditional CVD risk factors modestly attenuated the HIV association (0.148 mm, 95% CI 0.072-0.224, P = 0.0001). For the common carotid, HIV infection was independently associated with greater IMT (0.033 mm, 95% CI 0.010-0.056, P = 0.005). The association of HIV infection with IMT was similar to that of smoking, which was also associated with greater IMT (internal 0.173 mm, common 0.020 mm).

CONCLUSION

Even after adjustment for traditional CVD risk factors, HIV infection was accompanied by more extensive atherosclerosis measured by IMT. The stronger association of HIV infection with IMT in the internal/bulb region compared with the common carotid may explain previous discrepancies in the literature. The association of HIV infection with IMT was similar to that of traditional CVD risk factors, such as smoking.

OBJECTIVE

In randomized trials, the most common way to measure the effect of treatment on the frequency and severity of menopausal hot flashes is a 7-day self-reported diary. However, adherence with completing the hot flash diary in real time may be poor, and completing a diary is cumbersome for study participants. Our objective was to determine if a shorter diary for recording self-reported hot flashes is as accurate and precise as the traditional 7-day diary.

METHODS

Using cross-sectional data from a multicenter randomized clinical trial of an herbal preparation (MF101, an estrogen receptor beta-selective agonist for treatment of menopausal hot flashes), we compared findings based on shorter diaries with findings based on a 7-day diary.

RESULTS

With 3 days of diary keeping, the mean number of hot flashes per day and mean severity were almost identical to the means based on the 7-day diary, the SDs of the means were almost identical, and the intraclass correlations were almost perfect. The difference in the mean number of hot flashes per day compared with the 7-day diary was only 12% of one hot flash. Data from a different clinical trial revealed similar correspondence between the findings of a 3- and 7-day diary.

CONCLUSIONS

In our study, the optimal duration of diary keeping to record menopausal hot flashes seems to be 3 days. In addition to being as good as a 7-day diary, a 3-day diary would be less burden on study participants and research staff and less expensive.