Rectal prolapse is typically a benign idiopathic condition. Rarely, rectal prolapse can be due to or associated with colorectal carcinoma. Here we present a middle‐aged gentleman with no previous ...medical or surgical history, who presented with rectal prolapse secondary to sigmoid adenocarcinoma.
Rectal prolapse secondary to sigmoid adenocarcinoma.
Drosophila mushroom body (MB) gamma neurons undergo axon pruning during metamorphosis through a process of localized degeneration of specific axon branches. Developmental axon degeneration is ...initiated by the steroid hormone ecdysone, acting through a nuclear receptor complex composed of USP (ultraspiracle) and EcRB1 (ecdysone receptor B1) to regulate gene expression in MB gamma neurons. To identify ecdysone-dependent gene expression changes in MB gamma neurons at the onset of axon pruning, we use laser capture microdissection to isolate wild-type and mutant MB neurons in which EcR (ecdysone receptor) activity is genetically blocked, and analyze expression changes by microarray. We identify several molecular pathways that are regulated in MB neurons by ecdysone. The most striking observation is the upregulation of genes involved in the UPS (ubiquitin-proteasome system), which is cell autonomously required for gamma neuron pruning. In addition, we characterize the function of Boule, an evolutionarily conserved RNA-binding protein previously implicated in spermatogenesis in flies and vertebrates. boule expression is downregulated by ecdysone in MB neurons at the onset of pruning, and forced expression of Boule in MB gamma neurons is sufficient to inhibit axon pruning. This activity is dependent on the RNA-binding domain of Boule and a conserved DAZ (deleted in azoospermia) domain implicated in interactions with other RNA-binding proteins. However, loss of Boule does not result in obvious defects in axon pruning or morphogenesis of MB neurons, suggesting that it acts redundantly with other ecdyonse-regulated genes. We propose a novel function for Boule in the CNS as a negative regulator of developmental axon pruning.
Departments of 1 Physiology, 2 Pathology, 3 Microbiology, and 4 Pediatrics, College of Medicine, University of South Alabama, Mobile, Alabama 36688
Submitted 25 March 2004
; accepted in final form 13 ...July 2004
To determine the influence of experimental model and strain differences on the relationship of vascular permeability to inflammatory cytokine production after high peak inflation pressure (PIP) ventilation, we used isolated perfused mouse lung and intact mouse preparations of Balb/c and B6/129 mice ventilated at high and low PIP. Filtration coefficients in isolated lungs and bronchoalveolar lavage (BAL) albumin in intact mice increased within 2030 min after initiation of high PIP in isolated Balb/c lungs and intact Balb/c, B6/129 wild-type, and p55 and p75 tumor necrosis factor (TNF) dual-receptor null mice. In contrast, the cytokine response was delayed and variable compared with the permeability response. In isolated Balb/c lungs ventilated with 2527 cmH 2 O PIP, TNF- , interleukin (IL)-1 , IL-1 , macrophage inflammatory protein (MIP)-2, and IL-6 concentrations in perfusate were markedly increased in perfusate at 2 and 4 h, but only MIP-2 was detectable in intact Balb/c mice using the same PIP. In intact wild-type and TNF dual-receptor null mice with ventilation at 45 cmH 2 O PIP, the MIP-2 and IL-6 levels in BAL were significantly increased after 2 h in both groups, but there were no differences between groups in the BAL albumin and cytokine concentrations or in lung wet-to-dry weight ratios. TNF- was not be detected in BAL fluids in any group of intact mice. These results suggest that the alveolar hyperpermeability induced by high PIP ventilation occurs very rapidly and is initially independent of TNF- participation and unlikely to depend on MIP-2 or IL-6.
ventilator induced lung injury; tumor necrosis factor- ; major intrinsic protein-2; interleukin-6; knockout mice
Address for reprint requests and other correspondence: J. C. Parker, Dept. of Physiology, MSB 3024, College of Medicine, Univ. of South Alabama, Mobile, AL 36688 (E-mail: Jparker{at}usouthal.edu )
BACKGROUND AND PURPOSE:Enlarged perivascular spaces (EPVS) are considered subclinical markers of small vessel disease, associated with increased risk of stroke and dementia. Increasing evidence links ...chronic kidney disease (CKD) to small vessel disease. We explored the relationship between CKD and EPVS burden and the influence of racial group in this relation.
METHODS:Consecutive patients with stroke who underwent brain magnetic resonance imaging were included (n=894). Racial group was categorized as White, Black, or other (other racial groups). CKD was defined by glomerular filtration rate <60 mL/minute per 1.73 m for >3 months. EPVS were rated following a standardized method, dichotomized for analyses (mild <20 versus severe ≥20), and stratified by brain region (basal ganglia and centrum semiovale).
RESULTS:In multivariable-adjusted analysis, the association of CKD with severe EPVS varied across racial groups. Comparing patients with and without CKD within racial groups, we found that Whites with CKD had higher odds of severe centrum semiovale EPVS (odds ratio OR, 2.41 95% CI, 0.98–5.88). Among patients with CKD, Black patients had higher odds of severe EPVS in the basal ganglia and centrum semiovale compared with Whites (OR, 1.93 95% CI, 1.18–3.16 and OR, 1.90 95% CI, 1.16–3.11, respectively) and other racial groups (OR, 2.03 95% CI, 1.23–3.36 and OR, 2.02 95% CI, 1.22–3.34, respectively).
CONCLUSIONS:CKD was more prevalent in our sample of patients with stroke with severe EPVS in the centrum semiovale. The relation differed when stratified by racial group and brain topography. Further studies are needed to confirm that CKD may relate differently to subclinical measures of small vessel disease according to race.
Predators can have consequences on prey populations and communities that extend well beyond direct predator-induced mortality. Predator-prey interactions often affect prey feeding rates, growth ...rates, or fecundities, thereby significantly affecting reproductive success of prey adults. Thus, investigation of the sublethal fitness consequences of behavioral responses of prey to predators is essential to our understanding of the total impact of predators on prey populations and communities. Feeding (algal grazing) rates, growth rates, and fecundities of Baetis bicaudatus (Baetidae) larvae were measured in replicated circular flow-through stream channels to determine the sublethal consequences on fitness correlates of the presence of predatory stoneflies (Perlodidae). Gut fullness of 24-h starved Baetis larvae was measured using fluorometry after 24 h (short-term experiments) in four treatments: (1) ambient resource rocks and no predators, (2) low resource rocks and no predators, (3) ambient resource rocks and one female perlodid stonefly (Megarcys signata), or (4) Kogotus modestus whose mouthparts were glued to prevent lethal effects of predation. Mid-instar male and female Baetis larvae were reared for 3 wk until wing pad maturation (long-term experiments) and subjected to all but the Kogotus treatment. Predator avoidance significantly reduced levels of Baetis gut fullness, over the short term, to levels intermediate between the high and low resource treatments. Longer term residence with predatory stoneflies caused larvae of both male and female Baetis to mature at significantly smaller sizes than in the treatment with ambient food but no predators. Mayflies with predators matured at sizes similar to those held with low food levels over the long term. Interestingly, both starved larvae and those avoiding predators did not grow during the experimental period in contrast to about a 50% growth rate of larvae experiencing ambient food levels, but no predators. Similarly, egg biomass per mature female larva was significantly reduced in both starved and predator treatments. The proportion of total body mass allocated to eggs was only reduced in starved mayflies indicating that the females avoiding predators accrued less total mass, but allocated a similar proportion to eggs as did well-fed Baetis. These data convincingly demonstrate that predator avoidance can have dramatic consequences on mayfly fitness. The mechanism explaining those fitness consequences is probably a disruptive drift/swim response by Baetis to encounters with stoneflies, which reduces Baetis' feeding rates. If we accept the assumption that natural selection has shaped the foraging behavior of organisms to maximize fitness, foragers need to make decisions that maximize both survivorship (minimizing risk of predation) and fecundity. In mayflies fecundity is entirely a function of resource acquisition by the larvae, which makes them particularly vulnerable to such sublethal effects of predation. Nonetheless, we suspect that the types of sublethal costs of predator avoidance documented by this and other recent studies are nearly universal consequences or organisms foraging under predation risk.
During eye development in Drosophila, cell cycle progression is coordinated with differentiation. Prior to differentiation, cells arrest in G1 phase anterior to and within the morphogenetic furrow. ...We show that Decapentaplegic (Dpp), a TGF-β family member, is required to establish this G1 arrest, since Dpp-unresponsive cells located in the anterior half of the morphogenetic furrow show ectopic S phases and ectopic expression of the cell cycle regulators Cyclins A, E and B. Conversely, ubiquitous over-expression of Dpp in the eye imaginal disc transiently inhibits S phase without affecting Cyclin E or Cyclin A abundance. This Dpp-mediated inhibition of S phase occurs independently of the Cyclin A inhibitor Roughex and of the expression of Dacapo, a Cyclin E-Cdk2 inhibitor. Furthermore, Dpp-signaling genes interact genetically with a hypomorphic cyclin E allele. Taken together our results suggest that Dpp acts to induce G1 arrest in the anterior part of the morphogenetic furrow by a novel inhibitory mechanism. In addition, our results provide evidence for a Dpp-independent mechanism that acts in the posterior part of the morphogenetic furrow to maintain G1 arrest.
The classical model of independent random single deformation faults and twin faulting in face‐centered‐cubic and hexagonal close packing is revisited. The model is extended to account for the whole ...range of faulting probabilities. The faulting process resulting in the final stacking sequences is described by several equivalent computational models. The probability sequence tree is established. Random faulting is described as a finite‐state automaton machine. An expression giving the percent of hexagonality from the faulting probabilities is derived. The average sizes of the cubic and hexagonal domains are given as a function of single deformation and twinning fault probabilities. An expression for the probability of finding a given sequence within the complete stacking arrangement is also derived. The probability P0(Δ) of finding two layers of the same type Δ layers apart is derived. It is shown that previous generalizations did not account for all terms in the final probability expressions. The different behaviors of the P0(Δ) functions are discussed.
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