The Association Between Breast Density and Gut Microbiota Composition at 2 Years Post-Menarche: A Cross-Sectional Study of Adolescents in Santiago, Chile

The gut microbiome has been linked to breast cancer via immune, inflammatory, and hormonal mechanisms. We examined the relation between adolescent breast density and gut microbial composition and function in a cohort of Chilean girls. This cross-sectional study included 218 female participants in the Growth and Obesity Cohort Study who were 2 years post-menarche. We measured absolute breast fibroglandular volume (aFGV) and derived percent FGV (%FGV) using dual energy X-ray absorptiometry. All participants provided a fecal sample. The gut microbiome was characterized using 16S ribosomal RNA sequencing of the V3-V4 hypervariable region. We examined alpha diversity and beta diversity across terciles of %FGV and aFGV. We used MaAsLin2 for multivariable general linear modeling to assess differential taxa and predicted metabolic pathway abundance (MetaCyc) between %FGV and aFGV terciles. All models were adjusted for potential confounding variables and corrected for multiple comparisons. The mean %FGV and aFGV was 49.5% and 217.0 cm³, respectively, among study participants. Similar median alpha diversity levels were found across %FGV and aFGV terciles when measured by the Shannon diversity index (%FGV T1: 4.0, T2: 3.9, T3: 4.1; aFGV T1: 4.0, T2: 4.0, T3: 4.1). %FGV was associated with differences in beta diversity (R^{2 =}0.012, p=0.02). No genera were differentially abundant when comparing %FGV nor aFGV terciles after adjusting for potential confounders (q > 0.56 for all genera). We found no associations between predicted MetaCyc pathway abundance and %FGV and aFGV. Overall, breast density measured at 2 years post-menarche was not associated with composition and predicted function of the gut microbiome among adolescent Chilean girls.

Differential expression of striatal proteins in a mouse model of DOPA-responsive dystonia reveals shared mechanisms among dystonic disorders

Dystonia is characterized by involuntary muscle contractions that cause debilitating twisting movements and postures. Although dysfunction of the basal ganglia, a brain region that mediates movement, is implicated in many forms of dystonia, the underlying mechanisms are unclear. The inherited metabolic disorder DOPA-responsive dystonia is considered a prototype for understanding basal ganglia dysfunction in dystonia because it is caused by mutations in genes necessary for the synthesis of the neurotransmitter dopamine, which mediates the activity of the basal ganglia. Therefore, to reveal abnormal striatal cellular processes and pathways implicated in dystonia, we used an unbiased proteomic approach in a knockin mouse model of DOPA-responsive dystonia, a model in which the striatum is known to play a central role in the expression of dystonia. Fifty-seven of the 1805 proteins identified were differentially regulated in DOPA-responsive dystonia mice compared to control mice. Most differentially regulated proteins were associated with gene ontology terms that implicated either mitochondrial or synaptic dysfunction whereby proteins associated with mitochondrial function were generally over-represented and proteins associated with synaptic function were largely under-represented. Remarkably, nearly 20% of the differentially regulated striatal proteins identified in our screen are associated with pathogenic variants that cause inherited disorders with dystonia as a sign in humans suggesting shared mechanisms across many different forms of dystonia.

Near-total intestinal aganglionosis: long-term follow-up of a morbid condition

PURPOSE

The aim of this study was to understand the long-term outcome of near-total intestinal aganglionosis (NTIA).

METHODS

The study was an institutional review of all patients with NTIA between 1974 and 1999, inc!usive. Seven full-term babies were identified (4 boys, 3 girls). Mean birth weight was 3.2 kg (range, 2.7 to 4.1). Patients included 1 pair of siblings and 1 Down's syndrome baby. All 7 had obstruction within 5 days of life. One patient experienced bowel perforation. All 7 had NTIA diagnosed within the first 2 months of life. In 2 of 7, aganglionosis began 10 cm distal to the ligament of Treitz (LOT). The longest segment of normal small bowel was 130 cm from the LOT. Five of 7 babies underwent a stoma between day of life (DOL) 1 and 15.

RESULTS

Two of three "long-term" survivors (>2 years) had corrective surgery by 13 months. The first received extended jejuno-ileal myotomy and myectomy with multiple postoperative problems. She died at 8 years of age of complications of total parenteral nutrition (TPN). The second underwent myotomy, resection and patch graft to jejunum, and several jejunostomy revisions. All of the involved bowel eventually was resected. The 3 of 7 who lived more than 1 year all took some nutrition orally. Three died, between 3 months and 8 years of age, of complications of TPN. There are 2 survivors at 3 and 7 years of age. Survival has not correlated with the length of aganglionic bowel.

CONCLUSIONS

Aganglionosis involving most of the bowel has a high morbidity and mortality rate. Since 1990 a more aggressive surgical approach has resulted in improved survival rates but with significant morbidity. For children surviving beyond 3 months of age, outcome was less dismal. Some patients may benefit from extended jejunal myotomy or myectomy. However, postoperative complications are the rule, not the exception.

Identification of nucleoside transport binding sites in the human myocardium

The role of nucleoside transport in ischemia-reperfusion injury and arrhythmias has been well documented in various animal models using selective blockers. However, clinical application of nucleoside transport inhibitors remains to be demonstrated in humans. It is not known whether human heart has nucleoside transport similar to that of animals. The aim of this study is to pharmacologically identify the presence of nucleoside transport binding sites in the human myocardium compared to animals. Myocardial tissue was obtained from guinea pig left and right ventricle, canine left ventricle, human intraoperative right atrium and human cadaveric right atrium and right and left ventricles. Myocardial preparations were obtained from tissue samples after homogenized and a differential centrifugation. Equilibrium binding assays were performed using [3H]-p-nitrobenzylthioinosine (NBMPR) at room temperature in the presence or absence of non-radioactive NBMPR or other nucleoside transport blockers such as p-nitrobenzylthioguanosine dipyridamole, lidoflazine, papaverin, adenosine and doxorubcine. From saturation curves and inhibition kinetics, we determined the relative maximal binding (Bmax) and dissociation constant (Kd) of [3H]-NBMPR binding of human myocardial preparations. Results demonstrated that the fresh human myocardial preparations have a specific binding site for NBMPR with a Bmax of 283+/-32 fmol/mg protein and Kd of 0.56+/-0.12 nM. These values are lower than those obtained from guinea pigs (Bmax = 1440+/-187 fmol/mg protein and Kd = 0.21+/-0.03 nM) and canine atrium (Bmax 594+/-73 fmol/mg protein, and Kd = 1.12+/-0.22 nM). Displacement kinetics studies revealed the relative potencies (of certain unrelated drugs as follow: p-nitrobenzylthioguanosine > dipyridamole > lidoflazine > pavaverine > Diltazam > adenosine > doxyrubicin. It is concluded that human myocardium contains an active nucleoside transport site which may play a crucial role in post-ischemic reperfusion-mediated injury in a wide spectrum of ischemic syndromes.

Rehbein's anterior resection in Hirschsprung's disease, using a circular stapler

The results of 30 patients with Hirschsprung's disease, operated by Rehbein's anterior resection, have been evaluated. In 26 children the anastomosis was constructed with a circular stapler (Ethicon Proximate ILS) and in 4 it was handsutured. When a stapler was used, technical problems in 4, with a defect in the rings of bowel after firing the instrument, necessitated reinforcing sutures. The level of the anastomosis was significantly lower in the children in which a stapler was used. Eight children were operated by dorsal myectomy (DRM) prior to and 4 after anterior resection. The children with DRM prior to anterior resection had a significantly lower requirement for postoperative dilations. Early postoperative complications included 3.3% mortality, 6.7% enterocolitis, 3.3% anastomotic insufficiency, 3.3% early ileus and 10.0% wound infection. Three patients (10.0%) were operated for postoperative anastomotic stricture, one requiring anastomotic revision and two requiring DRM. At follow-up two children (7.4%) reported constipation with regular requirement for enemas and two (7.4%) reported daily encopresis. Twenty-three patients had 1-5 bowel movements per day and 4 patients had more than 5. In our experience the use of a circular stapler makes it possible to perform a lower anastomosis. We believe that this technique gives a wider and more elastic anastomosis and is technically less difficult to handle than a handsutured anastomosis.