Starling curves and central venous pressure

Recent studies challenge the utility of central venous pressure monitoring as a surrogate for cardiac preload. Starting with Starling’s original studies on the regulation of cardiac output, this review traces the history of the experiments that elucidated the role of central venous pressure in circulatory physiology. Central venous pressure is an important physiologic parameter, but it is not an independent variable that determines cardiac output

Cognitive performance in healthy women during induced hypogonadism and ovarian steroid addback

Background—Gynecology clinic-based studies have consistently demonstrated that induced hypogonadism is accompanied by a decline in cognitive test performance. However, a recent study in healthy asymptomatic controls observed that neither induced hypogonadism nor estradiol replacement influenced cognitive performance. Thus the effects of induced hypogonadism on cognition might not be uniformly experienced across individual women. Moreover, discrepancies in the effects of hypogonadism on cognition also could suggest the existence of specific risk phenotypes that predict a woman’s symptomatic experience during the menopause. In this study, we examined the effects of induced hypogonadism and ovarian steroid replacement on cognitive performance in healthy premenopausal women. Methods—Ovarian suppression was induced with a GnRH agonist (Lupron) and then physiologic levels of estradiol and progesterone were re-introduced in 23 women. Cognitive tests were administered during each hormone condition. To evaluate possible practice effects arising during repeated testing, an identical battery of tests was administered at the same time intervals in 11 untreated women. Results—With the exception of an improved performance on mental rotation during estradiol, we observed no significant effects of estradiol or progesterone on measures of attention, concentration, or memory compared with hypogonadism. Conclusions—In contrast to studies in which a decline in cognitive performance was observed in women receiving ovarian suppression therapy for an underlying gynecologic condition, we confirm a prior report demonstrating that short term changes in gonadal steroids have a limited effect on cognition in young, healthy, women. Differences in the clinical characteristics of the women receiving GnRH agonists could predict a risk for ovarian steroid-related changes in cognitive performance during induced, and possibly, natural menopause

Sex differences in visuospatial abilities persist during induced hypogonadism

Despite well-established sex differences in the performance on tests of several cognitive domains (e.g., visuospatial ability), few studies in humans have evaluated if these sex differences are evident both in the presence of circulating sex hormones and during sex steroid hormonal suppression. Sex differences identified in the relative absence of circulating levels of estradiol and testosterone suggest that differences in brain structure or function exist independent of current hormonal environment and are more likely a reflection of differing developmental exposures and/or genetic substrates

Diabetic neuropathic foot ulcers. The association of wound size, wound duration, and wound grade on healing

WSTĘP. Celem badań była ocena, czy możliwe jest określenie prostych (niezłożonych) czynników ryzyka, na podstawie których można stwierdzić, czy u chorych z owrzodzeniami stopy na tle neuropatii cukrzycowej standardowa terapia będzie skuteczna. MATERIAŁ I METODY. Było to badanie kohortowe, w którym oceniano grupę ponad 31 000 pacjentów z owrzodzeniem stopy w przebiegu neuropatii cukrzycowej, będących pod opieką Curative Health Services System (CHS). Stosując wieloczynnikową logistyczną regresję, oceniano związki pomiędzy wielkością rany, okresem jej trwania, stopniem zaawansowania rany oraz innych zmiennych (i ich wpływu) a wyleczeniem w ciągu 20 tygodni opieki. WYNIKI. Wykazano, że wielkość rany, okres jej trwania i stopień jej zaawansowania istotnie wpływały na prawdopodobieństwo wygojenia się rany w ciągu 20 tygodni leczenia. Dodatkowo zauważono, że leczenie w specjalistycznym ośrodku leczenia ran, niezależnie od tego, czy jednostką analizy była jedna rana pacjenta, czy wszystkie, oraz bez względu na stosowane dodatkowe terapie, nie zmieniało istotnie tej zależności. WNIOSKI. Wykazano, że trzy łatwe do oceny czynniki ryzyka są związane z gojeniem się ran. Uzyskane wyniki powinny pomóc klinicystom w ustaleniu, jakie jest prawdopodobieństwo wyleczenia rany, jak również pomóc w projektowaniu dalszych badań klinicznych.INTRODUCTION. The goal of this study was to evaluate whether simple risk factors can be identified that successfully characterize who will heal and who will not heal among patients who have received standard therapy for diabetic neuropathic foot ulcers. MATERIAL AND METHODS. For this cohort study, we evaluated > 31,000 individuals with a diabetic neuropathic foot ulcer seen in the Curative Health Services System. Using multivariate logistic regression, we evaluated the association between wound size, wound duration, wound grade, and other variables and their effect on whether a patient would heal by the 20th week of care. RESULTS. We demonstrated that wound size, wound duration, and wound grade are all significantly associated with the likelihood of a wound healing by the 20th week of care. In addition, we noted that these associations were not significantly affected by the treating wound care center, whether the unit of analysis was one wound on a patient or all of their wounds, or current adjuvant therapies. CONCLUSIONS. We have shown that three easy-to- -measure risk factors are associated with a wound healing. These results should help clinicians understand the likelihood that a wound will heal and help those conducting clinical investigations to design better trials

Composition of the L5 Mars Trojans: Neighbors, not Siblings

Mars is the only terrestrial planet known to have Tro jan (co-orbiting) asteroids, with a confirmed population of at least 4 objects. The origin of these objects is not known; while several have orbits that are stable on solar-system timescales, work by Rivkin et al. (2003) showed they have compositions that suggest separate origins from one another. We have obtained infrared (0.8-2.5 micron) spectroscopy of the two largest L5 Mars Tro jans, and confirm and extend the results of Rivkin et al. (2003). We suggest that the differentiated angrite meteorites are good spectral analogs for 5261 Eureka, the largest Mars Trojan. Meteorite analogs for 101429 1998 VF31 are more varied and include primitive achondrites and mesosiderites.Comment: 14 manuscript pages, 1 table, 6 figures. To be published in Icarus. See companion paper 0709.1921 by Trilling et a

Comprehensive comparative analysis of RNA sequencing methods for degraded or low input samples

RNA-Seq is an effective method to study the transcriptome, but can be difficult to apply to scarce or degraded RNA from fixed clinical samples, rare cell populations, or cadavers. Recent studies have proposed several methods for RNA-Seq of low quality and/or low quantity samples, but their relative merits have not been systematically analyzed. Here, we compare five such methods using metrics relevant to transcriptome annotation, transcript discovery, and gene expression. Using a single human RNA sample, we constructed and sequenced ten libraries with these methods and two control libraries. We find that the RNase H method performed best for low quality RNA, and confirmed this with actual degraded samples. RNase H can even effectively replace oligo (dT) based methods for standard RNA-Seq. SMART and NuGEN had distinct strengths for low quantity RNA. Our analysis allows biologists to select the most suitable methods and provides a benchmark for future method development

In search of the authentic nation: landscape and national identity in Canada and Switzerland

While the study of nationalism and national identity has flourished in the last decade, little attention has been devoted to the conditions under which natural environments acquire significance in definitions of nationhood. This article examines the identity-forming role of landscape depictions in two polyethnic nation-states: Canada and Switzerland. Two types of geographical national identity are identified. The first – what we call the ‘nationalisation of nature’– portrays zarticular landscapes as expressions of national authenticity. The second pattern – what we refer to as the ‘naturalisation of the nation’– rests upon a notion of geographical determinism that depicts specific landscapes as forces capable of determining national identity. The authors offer two reasons why the second pattern came to prevail in the cases under consideration: (1) the affinity between wild landscape and the Romantic ideal of pure, rugged nature, and (2) a divergence between the nationalist ideal of ethnic homogeneity and the polyethnic composition of the two societies under consideration

Rare Copy Number Variants in \u3cem\u3eNRXN1\u3c/em\u3e and \u3cem\u3eCNTN6\u3c/em\u3e Increase Risk for Tourette Syndrome

Tourette syndrome (TS) is a model neuropsychiatric disorder thought to arise from abnormal development and/or maintenance of cortico-striato-thalamo-cortical circuits. TS is highly heritable, but its underlying genetic causes are still elusive, and no genome-wide significant loci have been discovered to date. We analyzed a European ancestry sample of 2,434 TS cases and 4,093 ancestry-matched controls for rare (\u3c 1% frequency) copy-number variants (CNVs) using SNP microarray data. We observed an enrichment of global CNV burden that was prominent for large (\u3e 1 Mb), singleton events (OR = 2.28, 95% CI [1.39–3.79], p = 1.2 × 10−3) and known, pathogenic CNVs (OR = 3.03 [1.85–5.07], p = 1.5 × 10−5). We also identified two individual, genome-wide significant loci, each conferring a substantial increase in TS risk (NRXN1 deletions, OR = 20.3, 95% CI [2.6–156.2]; CNTN6 duplications, OR = 10.1, 95% CI [2.3–45.4]). Approximately 1% of TS cases carry one of these CNVs, indicating that rare structural variation contributes significantly to the genetic architecture of TS