Increased Asymmetric and Multi-Daughter Cell Division in Mechanically Confined Microenvironments

As the microenvironment of a cell changes, associated mechanical cues may lead to changes in biochemical signaling and inherently mechanical processes such as mitosis. Here we explore the effects of confined mechanical environments on cellular responses during mitosis. Previously, effects of mechanical confinement have been difficult to optically observe in three-dimensional and in vivo systems. To address this challenge, we present a novel microfluidic perfusion culture system that allows controllable variation in the level of confinement in a single axis allowing observation of cell growth and division at the single-cell level. The device is capable of creating precise confinement conditions in the vertical direction varying from high (3 µm) to low (7 µm) confinement while also varying the substrate stiffness (E = 130 kPa and 1 MPa). The Human cervical carcinoma (HeLa) model with a known 3N+ karyotype was used for this study. For this cell line, we observe that mechanically confined cell cycles resulted in stressed cell divisions: (i) delayed mitosis, (ii) multi- daughter mitosis events (from 3 up to 5 daughter cells), (iii) unevenly sized daughter cells, and (iv) induction of cell death. In the highest confined conditions, the frequency of divisions producing more than two progeny was increased an astounding 50-fold from unconfined environments, representing about one half of all successful mitotic events. Notably, the majority of daughter cells resulting from multipolar divisions were viable after cytokinesis and, perhaps suggesting another regulatory checkpoint in the cell cycle, were in some cases observed to re-fuse with neighboring cells post-cytokinesis. The higher instances of abnormal mitosis that we report in confined mechanically stiff spaces, may lead to increased rates of abnormal, viable, cells in the population. This work provides support to a hypothesis that environmental mechanical cues influences structural mechanisms of mitosis such as geometric orientation of the mitotic plane or planes

A mannose-binding lectin-defective haplotype is a risk factor for gastric cancer.

We suggest that the low MBL activity in patients bearing the HYPD haplotype may allow enhanced bacterial colonization of the gastric mucosa and reduce down-regulation of IL-1 beta production, thereby increasing the risk of gastric cancer. Otherwise, MBL2 HYPD haplotype may be in linkage disequilibrium with variants of other genes responsible for the increased risk of gastric cancer. To conclude, the MBL2-defective HYPD haplotype may be a novel genetic marker of risk for gastric cancer in Helicobacter pylori-infected patients

Functional consequences and intracoronary localization of alpha-adrenergic stimulation of the canine coronary circulation

Although alpha-adrenergic stimulation can increase coronary vascular resistance, it remains unknown whether the vasoconstriction can override intrinsic coronary regulatory influences to produce ischemia. Methoxamine, 2 to 4 mg, was infused into the circumflex coronary artery of 23 chloralose-anesthetized open chest dogs, and resulted in a 68% increase in coronary vascular resistance. The functional consequence of this increased coronary vascular resistance was assessed by gated radionuclide ventriculography and ST-T wave changes on the electrocardiogram.In six dogs (Croup 1), aortic pressure changed trivially (<5 mm Hg) to allow distinction between direct effects of the flow reduction and indirect effects of increased aortic pressure. In this group, coronary blood flow decreased 33% from a control value of 44 ± 10 ml/min (p < 0.001) and left ventricular ejection fraction decreased from 0.54 ± 0.12 to 0.46 ± 0.10 (p < 0.025). In eight dogs (Group II) in which aortic pressure increased by more than 5 mm Hg, left ventricular ejection fraction decreased from 0.46 ± 0.07 to 0.39 ± 0.09 (p < 0.002). Pressure gradients were measured between the aorta and a distal coronary artery branch to calculate small and large vessel resistances separately in four other dogs (Group III). The resistance of small coronary arteries accounted for 92% of the total increase in coronary vascular resistance produced by methoxamine. In five other dogs (Group IV), intracoronary methoxamine, 2 mg, produced ST-T wave changes suggestive of ischemia as it increased coronary vascular resistance by 33%.In conclusion, this study demonstrated that methoxamine caused functionally significant vasoconstriction of small coronary arteries as shown by the decreased left ventricular ejection fraction and ST-T wave changes. These findings suggest that alpha-adrenergic vasoconstriction can override coronary regulatory influences to cause ischemia

Pressure injuries in elderly with acute myocardial infarction

OBJECTIVES: To assess pressure injury (PI) incidence among patients hospitalized for acute myocardial infarction (AMI) in an intensive coronary care unit (ICCU) and to detect the impact of specific risk factors on the development of PI in this clinical setting. PATIENTS AND METHODS: Prospective cohort study in ICCU setting. Patients admitted for AMI: patients mean age 67.5±11.5 years (n=165). Norton Scale, Mini Nutritional Assessment (MNA), demographic, clinical and biochemical data collected at the time of ICCU admission have been tested in a logistic model to assess the odds ratios (ORs) of PI risk development. The jackknifed area under the receiver operating characteristic curve (AUC) and the decision curve analysis have been employed to assess the additive predictive value of a factor. RESULTS: Twenty-seven (16.3%) patients developed PIs. An increased PI risk was associated with advanced age (OR =2.5 every 10-year increase; 95% CI =1.1-5.7), while probability of PI development was reduced in patients with higher left ventricular ejection fraction (LVEF) (OR =0.4 every 5% increase; 95% CI =0.24-0.66), MNA score (OR =0.65 every unit change; 95% CI =0.44-0.95) and Norton Scale score (OR =0.7 every unit change; 95% CI =0.57-0.88). The AUC and the decision curve analysis showed that LVEF inclusion improved the discrimination power and the clinical net benefit of the final model. CONCLUSION: Age, LVEF, Norton Scale and MNA scores have a strong and independent clinical value as predictors of in-hospital PI development in patients with AMI. This finding has the potential to improve the clinical management of patients admitted in ICCU

Epidermal innervation morphometry by immunofluorescence and bright-field microscopy

We investigated the agreement between simple indirect immunofluorescence (IF) and bright-field immunohistochemistry (BFI) on free-floating sections for intraepidermal nerve fiber density (IENFD) quantification. Fifty-five healthy subjects and 63 patients with probable small fiber neuropathy (SFN) underwent two adjacent skin biopsies at the distal leg processed by IF and BFI technique. Agreement between IENFD pairs obtained by each method was assessed by Bland-Altman testing. The area under the curve of the receiving operating characteristics (ROC) curves was used to compare the discrimination ability. The diagnostic judgment was based on sex and age-adjusted normative values. IF and BFI showed good correlation (r = 0.81), with a ratio of about 2:1 and a mean difference of 5.5 ± 3.0 IENF per millimeter between paired measures, as demonstrated by linear regression and Bland-Altman test analyses. The square root transformation confirmed a Poisson distribution of the data and a fixed bias between IF and BFI measurements. The ROC curves analysis demonstrated a striking overlap between IF and BFI (0.83 and 0.82; p = 0.72). The diagnosis of SFN disagreed in only 6.7% of cases when the judgment was based on a difference of >1 IENF from 5% cut-off value. IF and BFI showed comparable diagnostic efficiency when referred to appropriate normative reference values