Background & AimsThe gastrointestinal syndrome is an illness of the intestine caused by high levels of radiation. It is characterized by extensive loss of epithelial tissue integrity, which initiates a regenerative response by intestinal stem and precursor cells. The intestine has 24-hour rhythms in many physiological functions that are believed to be outputs of the circadian clock: a molecular system that produces 24-hour rhythms in transcription/translation. Certain gastrointestinal illnesses are worsened when the circadian rhythms are disrupted, but the role of the circadian clock in gastrointestinal regeneration has not been studied.MethodsWe tested the timing of regeneration in the mouse intestine during the gastrointestinal syndrome. The role of the circadian clock was tested genetically using the BMAL1 loss of function mouse mutant in vivo, and in vitro using intestinal organoid culture.ResultsThe proliferation of the intestinal epithelium follows a 24-hour rhythm during the gastrointestinal syndrome. The circadian clock runs in the intestinal epithelium during this pathologic state, and the loss of the core clock gene, BMAL1, disrupts both the circadian clock and rhythmic proliferation. Circadian activity in the intestine involves a rhythmic production of inflammatory cytokines and subsequent rhythmic activation of the JNK stress response pathway.ConclusionsOur results show that a circadian rhythm in inflammation and regeneration occurs during the gastrointestinal syndrome. The study and treatment of radiation-induced illnesses, and other gastrointestinal illnesses, should consider 24-hour timing in physiology and pathology.

Sinus lifting with simultaneous implant placement could be used to treat atrophic maxilla in patients with minimal RABH when initial stability could be obtained by using taper designed implants with surgical techniques. Smoking is a possible factor for implant failure. Membrane perforation did not have an adverse effect on implant success if the membrane was repaired with absorbable membrane and fibrin glue.

SummaryThe circadian clock is a molecular pacemaker that produces 24-hr physiological cycles known as circadian rhythms. How the clock regulates stem cells is an emerging area of research with many outstanding questions. We tested clock function in vivo at the single cell resolution in the Drosophila intestine, a tissue that is exquisitely sensitive to environmental cues and has circadian rhythms in regeneration. Our results indicate that circadian clocks function in intestinal stem cells and enterocytes but are downregulated during enteroendocrine cell differentiation. Drosophila intestinal cells are principally synchronized by the photoperiod, but intestinal stem cell clocks are highly responsive to signaling pathways that comprise their niche, and we find that the Wnt and Hippo signaling pathways positively regulate stem cell circadian clock function. These data reveal that intestinal stem cell circadian rhythms are regulated by cellular signaling and provide insight as to how clocks may be altered during physiological changes such as regeneration and aging.

Despite the small sample size and the short follow-up period, our results indicate that SVPTC may not be as aggressive a subtype as previously thought.

BackgroundThis study was to evaluate the association of lumbar spine facet joint osteoarthritis (LSFJOA) identified by multi-detector computed tomography (MDCT) with age and low back pain (LBP) in an adult community-based population in Korea.MethodsA sample of 472 participants (age range, 20 to 84 years) who underwent MDCT imaging for abdominal or urological lesions, not for chief complaints of LBP, were included in this study. LSFJOA based on MDCT findings was characterized using four grades of osteoarthritis of the facet joints. The prevalence of LSFJOA according to age group (below 40 years, 40-49 years, 50-59 years, 60-69 years, and above 70 years), gender, and spinal level was analyzed using chi-square tests and the association between LBP and LSFJOA adjusting for age, gender, and spine level was analyzed using multiple binary logistic regression test.ResultsEighty-three study subjects (17.58%) had LSFJOA (grade ≥ 2). The prevalence of LSFJOA was not associated with gender (p = 0.092). The prevalence of LSFJOA increased with age (p = 0.015). The highest prevalence of LSFJOA was observed at L4-5 in men (p = 0.001) and at L5-S1 in women (p = 0.003), and at L5-S1 in the overall population (p = 0.000). LSFJOA was not associated with LBP in men (p = 0.093) but was associated with LBP in women (p = 0.003), especially at L3-4 (p = 0.018) and L5-S1 (p = 0.026).ConclusionsThe prevalence of LSFJOA based on the computed tomography imaging was 17.58% in the adult community Korean population. The prevalence of LSFJOA increased with age, and the highest prevalence was noted at L5-S1. LSFJOA was not associated with LBP at any spinal level and age except at L3-4 and L5-S1 in women.