Global H. pylori recurrence, recrudescence, and re-infection status after successful eradication in pediatric patients: a systematic review and meta-analysis.

BACKGROUND: Little information is available regarding global H. pylori recurrence, recrudescence, and re-infection in pediatric patients after successful eradication, nor are their influencing factors clear. We conducted a systematic review and meta-analysis to determine global H. pylori recurrence status and its influencing factors in children and adolescents to improve infection management and disease prevention. METHODS: Published studies on H. pylori recurrence in children and adolescents were collected from major public databases until January 2023. H. pylori recurrences were determined using randomized-effect and fixed-effect models. Stratified analysis was performed based on various regions, countries, publication time, human development indexes (HDIs), and ages. RESULTS: A total of 3310 relevant articles were screened, and 30 articles (1915 participants) were finally enrolled for analysis. The overall H. pylori recurrence rate was 19%, and the annual recurrence rate was 13%. In stratified analysis, H. pylori annual recurrence rate in Asian children was higher than that in Europe (17% vs. 6%) and higher in developing countries than in developed countries (18% vs. 5%). In children aged ≤ 5 years, ≤ 10 years, and 11-18 years, the H. pylori recurrence rates were 30%, 14%, and 8%, respectively. H. pylori recrudescence and re-infection rates were 6% and 10%, respectively, and its recurrence was inversely correlated with HDI. CONCLUSIONS: These results provide insights into global H. pylori recurrence, annual recurrence, recrudescence, and re-infection status in pediatric population. The stratified analysis revealed the pattern and seriousness of infection, which requires further efforts to improve patient care.

Decreased contrast sensitivity of visual cortical cells to visual stimuli accompanies a reduction of intracortical inhibition in old cats.

Psychophysical experiments on human and animal subjects have proven that aged individuals show significantly reduced visual contrast sensitivity compared with young adults. To uncover the possible neural mechanisms, we used extracellular single-unit recording techniques to examine the response of V(1) (primary visual cortex) neurons as a function of visual stimulus contrast in both old and young adult cats (Felis catus). The mean contrast sensitivity of V(1) neurons to visual stimuli in old cats decreased significantly relative to young adult cats, consistent with findings reported in old primates. These results indicate that aging can affect contrast sensitivity of visual cortical cells in both primate and non-primate mammalian animals, and might contribute to the reduction of perceptual visual contrast sensitivity in aged individuals. Further, V(1) cells of old cats exhibited increased responsiveness, decreased signal-to-noise ratio, and enlarged receptive field (RF) size compared with that of young adult cats, which indicated that decreased contrast sensitivity of V(1) neurons accompanied a reduction of intracortical inhibition during senescence.

Effects of urethane on the response properties of visual cortical neurons in young adult and old cats.

Previous studies have shown that visual cortical neurons in old mammals exhibit higher spontaneous activity, higher responsiveness to visual stimuli, and lower selectivity for stimulus orientations and motion directions than did neurons in young adult counterparts. However, whether the responsive difference in cortical neurons between young and old animals resulted from different effects induced by anesthetics has remained unclear. To clarify this issue, we recorded the response properties of individual neurons in the primary visual cortex of old and young adult cats while systematically varying the anesthesia level of urethane, a widely used anesthetic in physiology experiments. Our results showed that cumulatively administrating 50 mg and 100 mg of urethane upon the minimal level of urethane required to anesthetize an old or young adult cat did not significantly alter the degree of neuronal response selectivity for stimulus orientations and motion directions nor significantly change the visually-driven response and spontaneous activity of neurons in old and young adult cats. Cumulatively administrating 150 mg of urethane decreased neuronal responsiveness similarly in both age groups. Therefore, urethane appears to exert similar effects on neuronal response properties of old and young adult animals.

Decline of selectivity of V1 neurons to visual stimulus spatial frequencies in old cats.

OBJECTIVE: To examine whether the selectivity of visual cortical neurons to stimulus spatial frequencies would be affected by aging in cats. METHODS: In vivo extracellular single-unit recording techniques were employed to record the tuning responses of V1 neurons to different stimulus spatial frequencies in old and young adult cats. RESULTS: Statistical analysis showed that the mean optimal spatial frequency of grating stimuli that evoked the maximal response of V1 neurons in old cats was significantly lower than that in young adult cats. Furthermore, the mean high cut-off spatial frequency of grating stimuli that evoked the half amplitude of the maximal response of V1 neurons in old cats was also significantly lower than that in young adult cats. CONCLUSION: These results are consistent with those reported in the V1 of old monkeys, suggesting that the age-related decline in the selectivity of visual cortical cells to spatial frequency could be generalized to all mammalian species and might contribute to visual acuity reduction in senescent individuals.