Rectal Perforation by an Intrauterine Device Leading to Fatal Intra-Abdominal Sepsis and Necrotizing Fasciitis.

BACKGROUND: Colorectal injury from an intrauterine device (IUD) is rare but may lead to major complications. CASE: A 55-year-old woman presented to a tertiary care hospital with 4 days of generalized weakness, confusion, dysuria, and lower back pain. She provided a vague history of an unsuccessful attempt to remove an IUD 30 years prior. A computed tomography scan demonstrated an IUD in the rectal lumen, with gluteal and pelvic gas and fluid collections. Emergency surgery found necrotizing fasciitis. Despite multiple debridements, sigmoidoscopic IUD removal, and long-term intravenous antibiotics, the patient died from sepsis and multiorgan failure. CONCLUSION: IUDs require proper monitoring and timely removal to prevent potential complications associated with organ perforation.

Ionic mechanisms underlying tonic and burst firing behavior in subfornical organ neurons: a combined experimental and modeling study.

Subfornical organ (SFO) neurons exhibit heterogeneity in current expression and spiking behavior, where the two major spiking phenotypes appear as tonic and burst firing. Insight into the mechanisms behind this heterogeneity is critical for understanding how the SFO, a sensory circumventricular organ, integrates and selectively influences physiological function. To integrate efficient methods for studying this heterogeneity, we built a single-compartment, Hodgkin-Huxley-type model of an SFO neuron that is parameterized by SFO-specific in vitro patch-clamp data. The model accounts for the membrane potential distribution and spike train variability of both tonic and burst firing SFO neurons. Analysis of model dynamics confirms that a persistent Na+ and Ca2+ currents are required for burst initiation and maintenance and suggests that a slow-activating K+ current may be responsible for burst termination in SFO neurons. Additionally, the model suggests that heterogeneity in current expression and subsequent influence on spike afterpotential underlie the behavioral differences between tonic and burst firing SFO neurons. Future use of this model in coordination with single neuron patch-clamp electrophysiology provides a platform for explaining and predicting the response of SFO neurons to various combinations of circulating signals, thus elucidating the mechanisms underlying physiological signal integration within the SFO. NEW & NOTEWORTHY Our understanding of how the subfornical organ (SFO) selectively influences autonomic nervous system function remains incomplete but theoretically results from the electrical responses of SFO neurons to physiologically important signals. We have built a computational model of SFO neurons, derived from and supported by experimental data, which explains how SFO neurons produce different electrical patterns. The model provides an efficient system to theoretically and experimentally explore how changes in the essential features of SFO neurons affect their electrical activity.

Microscopic identification of novel cell types in the integument of larval lake sturgeon, Acipenser fulvescens.

Osmoregulation, respiration, nutrient/mineral transport, and defense mechanisms are all evident in the integument of fish. The role of the integument in these physiological processes is particularly important during early life history in larval fishes, as functional systems such as the gills and gastrointestinal tract are not fully developed. Using a variety of microscopy techniques, we describe the morphology of keratinocytes, mitochondria rich cells, ciliated cells and mucous cells of the skin, yolk sac, and gills. The cytology we observed was similar to previous studies describing the integument of larval fish, however, we have also identified two novel cell types on the integument of larval Lake Sturgeon, Acipenser fulvescens, between 9 and 34 days post fertilization. Our detailed analysis included a multifaceted microscopy approach using scanning electron, transmission electron, and light microscopy to elucidate the histology of the tissue and cellular morphology in addition to quantification and distribution of these novel cell types. The first cell type had a characteristic ampullary shape with a central cavity and a pore opening at the surface. The second, located on the free surface of the epidermis, had an uneven plasma membrane surface. Based on the abundance of secretory vesicles, organelles necessary for protein synthesis, and the lack of neural connection in both cell types, we propose these cells to be involved in the release of semiochemicals that may act as a pheromone, alarm substance, or chemical defense mechanism.

Regulation of calcium transport in the early life stages of an ancient fish, Acipenser fulvescens.

The freshwater, cartilaginous lake sturgeon (Acipenser fulvescens) encounters its greatest calcium (Ca(2+)) demand in the early life stages. In this study we examined Ca(2+) regulation of lake sturgeon larvae reared at three levels of environmental [Ca(2+)]-0.1, 0.2, and 1.5 mmol L(-1)-from hatch until after the transition to exogenous feeding. Examination of skin, gill, and yolk sac with scanning electron microscopy (SEM) indicated that the density and surface area of mitochondria-rich cells (MRCs) varies over developmental time but that availability of environmental Ca(2+) affected only MRC density. SEM results also demonstrated that Ca(2+) transport is adjusted in localization over the course of development, with the transition to primarily branchial uptake occurring earlier in the highest environmental [Ca(2+)]. Net whole-animal Ca(2+) flux was primarily dependent on influx rate. The increase in whole-body Ca(2+) uptake following the transition to exogenous feeding was greatest in larval lake sturgeon acclimated to low environmental [Ca(2+)], and it suggests that intestinal absorption may supplement enhanced branchial uptake in Ca(2+)-limited fish.