Predicting Non-Suicidal Self-Injury in Young Adults with and without Borderline Personality Disorder: a Multilevel Approach Combining Ecological Momentary Assessment and Self-Report Measures

Psychiatric Quarterly - Non-suicidal self-injury (NSSI) is an increasingly prevalent phenomenon associated with many detrimental outcomes, ranging from poor academic performance to suicide...     

Non-seasonality of births in Tierra del Fuego (Chile)

Tierra del Fuego is situated at the southern tip of the American continent, which conditions its environmental and climatic characteristics. The colonizing population arrived, at the end of the 19th century, from other Chilean regions (particularly from Chiloe) and diverse European countries, especially Britain and Croatia, but also Germany, Spain and Italy. In the present study, the existence of a seasonal pattern in 5430 births registered in the Chilean population of Tierra del Fuego from 1890 to 1995 was analysed. The analysis showed no seasonal distribution of births in the periods 1890-1920 and from 1946 to the present day, a phenomenon rarely reported in the literature. The absence of seasonality in birth distribution could be related to the great diversity in the origins of the population's families, the constant renovation of this and the declining importance of the administrative capital of the province of Tierra del Fuego, Porvenir, in favour of Punta Arenas, capital of the Magellanic region. In the period of maximum development of the capital of the province, a seasonal pattern was detected with a peak in April and a trough in October, which corresponds with a maximum of conceptions in July and, in general, during the early southern winter and a decline in births from late spring to mid-summer, with a trough in January. This birth distribution is interpreted as a subordination of activity and social life to the annual sheep cycle. In addition to temporal trends, the influence on the observed patterns of environmental parameters, father's occupation, seasonality of marriage and the origin of the parents were analysed.     

Does Cyclic Stress Play a Role in Highly Crosslinked Polyethylene Oxidation?

Background

Minimizing the impact of oxidation on ultrahigh-molecular-weight polyethylene components is important for preserving their mechanical integrity while in vivo. Among the strategies to reduce oxidation in modern first-generation highly crosslinked polyethylenes (HXLPEs), postirradiation remelting was considered to afford the greatest stability. However, recent studies have documented measurable oxidation in remelted HXLPE retrievals. Biologic prooxidants and physiologic loading have been proposed as potential mechanisms.

Questions/purposes

In our pilot study, we asked: (1) Does cyclic stress induced by wear or (2) by cyclic compression loading increase oxidation and crystallinity of remelted HXLPE? (3) Does oxidative aging reduce the wear resistance of remelted HXLPE?

Methods

Remelted and annealed HXLPE prisms (n = 1 per test condition) were tested in a wear simulator for 500,000 cycles. After wear testing, some samples were subjected to accelerated aging and then wear-tested again. Wear track volumes were characterized by confocal microscopy. Thin films (200-μm thick) were microtomed from wear prisms and then used for Fourier transform infrared spectroscopy oxidation and crystallinity assessments. Remelted HXLPE compression cylinders (n = 1 per test condition) were subjected to fatigue experiments and similar oxidation characterization.

Results

Remelted HXLPE qualitatively showed low oxidation indices (≤ 1) when subjected either to cyclic loading or aging alone. However, oxidation levels almost doubled in near-surface regions when remelted HXLPE samples underwent consecutive cyclic loading, artificial aging, and cyclic loading steps. The type of loading (wear versus compression fatigue) appeared to not affect the oxidation behavior in the studied conditions. Annealed HXLPE showed higher oxidation (oxidation index > 3) than remelted HXLPE and delamination wear. No delamination wear was observed in remelted HXLPE in agreement with its comparatively low oxidation levels (oxidation index < 3).

Conclusions

With the numbers available in our pilot study, the findings suggest that cyclic stress arising from a wear process or from cyclic compression may trigger the loss of oxidative stability of remelted HXLPE and contribute to synergistically accelerate its progression. Further studies of the effect of cyclic stress on oxidation of remelted HXLPE are needed.

Clinical Relevance

Retrieval studies are warranted to determine the natural history of the in vivo oxidation and wear behavior of first-generation, remelted HXLPE.     

The ordinary light microscope: an appropriate tool for provisional detection and identification of crystals in synovial fluid.

To determine if the ordinary light microscope is a useful tool in the detection and identification of crystals in synovial fluid 63 fluids (13 with monosodium urate (MSU), 14 with calcium pyrophosphate dihydrate (CPPD), one with both types of crystal, and 35 without crystals) were examined blindly by two observers, first with an ordinary light microscope, then with a polarising light microscope. Tentative identification of the crystals by their shape was attempted. The sensitivity of the ordinary light microscope for the detection of crystals was 96.2% and 100%, with specificity of 100% and 97.1% for observers 1 and 2, both with respect to the polarising light microscope. The concordance between observers for the ordinary light microscope was chi = 0.90 (0.897, 0.902) and for the polarising light microscope chi = 0.96 (0.958, 0.961). The specificity for identification of MSU and CPPD crystals by their shape with respect to the polarising light microscope was 92.3% and 85.7% for observers 1 and 2. When a polarising light microscope is not available examination of synovial fluid by an ordinary light microscope may allow a provisional diagnosis; definitive identification of the crystals requires a polarising light microscope.     

Electrocardiographic changes of ST-elevation myocardial infarction in patients with complete occlusion of the left main trunk without collateral circulation: Differential diagnosis and clinical considerations

Acute coronary syndromes due to involvement of the left main trunk usually present with subtotal occlusion and electrocardiographic pattern with predominant ST depression (non-ST-elevation myocardial infarction). The cases with complete occlusion frequently present an ST-elevation myocardial infarction pattern, but these patients usually die before reaching the hospital. We present a series of 7 patients with total left main trunk occlusion without collateral circulation showing ST-elevation myocardial infarction pattern. The electrocardiographic pattern is similar to left anterior descending coronary artery proximal occlusion to first septal and first diagonal but without ST elevation in V(1) and aVR because of left circumflex coronary artery compromise. In 4 (60%) of 7 of cases, there is also advanced right bundle-branch block plus superoanterior hemiblock. Despite severe clinical state at entrance (5/7 presented cardiac arrest/cardiogenic shock), 3 patients (43%) survived after percutaneous coronary intervention.