IHS Climate in Context: “Oil, Water, and Climate: Environmental Histories of Texas” – Panel

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IHS Climate in Context – Texas Deregulation and the 2021 Ice Storm

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α_1L-adrenoceptors mediate contraction of human erectile tissue

α1-adrenoceptor antagonists can impact upon sexual function and have potential in the treatment of erectile dysfunction. Human erectile tissue contains predominantly α1A-adrenoceptors, and here we examined whether contractions of this tissue are mediated by the functional phenotype, the α1L-adrenoceptor. Functional experiments using subtype selective agonists and antagonists, along with radioligand ([3H]tamsulosin) binding assays, were used to determine the α1-adrenoceptor population. A61603, a α1A-adrenoceptor agonist, was a full agonist with a potency 21-fold greater than that of noradrenaline. The α1A- and α1D-adrenoceptor antagonist tamsulosin antagonized noradrenaline responses with high affinity (pKD = 9.7 ± 0.3), whilst BMY7378 (100 nM) (α1D-adrenoceptor antagonist) failed to antagonize responses. In contrast, relatively low affinity estimates were obtained for both prazosin (pKD = 8.2 ± 0.1) and RS17053 (pKD = 6.9 ± 0.2), antagonists which discriminate between the α1A- and α1L-adrenoceptors. [3H]Tamsulosin bound with high affinity to the receptors of human erectile tissue (pKD = 10.3 ± 0.1) with a receptor density of 28.1 ± 1.4 fmol mg−1 protein. Prazosin displacement of [3H]tamsulosin binding revealed a single homogenous population of binding sites with a relatively low affinity for prazosin (pKi = 8.9). Taken together these data confirm that the receptor mediating contraction in human erectile tissue has the pharmacological properties of the α1L-adrenoceptor. Keywords: Erectile tissue, α1-adrenoceptor subtypes, α1L-adrenoceptor, Tamsulosin, Prazosi

To understand muscle you must take it apartle

Striated muscle is an elegant system for study at many levels. Much has been learned about the mechanism of contraction from studying the mechanical properties of intact and permeabilized (or skinned) muscle fibers. Structural studies using electron microscopy, X-ray diffraction or spectroscopic probes attached to various contractile proteins were possible because of the highly ordered sarcomeric arrangement of actin and myosin. However, to understand the mechanism of force generation at a molecular level, it is necessary to take the system apart and study the interaction of myosin with actin using in vitro assays. This reductionist approach has lead to many fundamental insights into how myosin powers muscle contraction. In addition, nature has provided scientists with an array of muscles with different mechanical properties and with a superfamily of myosin molecules. Taking advantage of this diversity in myosin structure and function has lead to additional insights into common properties of force generation. This review will highlight the development of the major assays and methods that have allowed this combined reductionist and comparative approach to be so fruitful. This review highlights the history of biochemical and biophysical studies of myosin and demonstrates how a broad comparative approach combined with reductionist studies have led to a detailed understanding of how myosin interacts with actin and uses chemical energy to generate force and movement in muscle contraction and motility in general

Antiretroviral Therapy

In this article, the scientific evidence and professional guidelines regarding the timing of antiretroviral therapy initiation are reviewed, with discussion of the increasingly persuasive evidence in favor of starting treatment early in the course of human immunodeficiency virus disease

Response Rate and Stakeholder Attitude towards Use of Interactive Electronic Audience Response (Clickers) in Beef Extension Programming

Effectively measuring short-term impact, particularly a change in knowledge resulting from extension programming can prove to be challenging. Clicker-based technology, when used properly, is one alternative that may allow educators to better evaluate this aspect of the logic model. While the potential interface between clicker technology and extension programming has been regularly hypothesized about, the success of use and stakeholder attitude towards such technology in an extension setting has not been well defined to date. Based on data collected during Iowa Beef Center winter extension programming, clicker-based technology yielded increased participant response rates when compared to hand-written program evaluations. Moreover, the technology effectively monitored change in knowledge and was viewed in an overwhelmingly positive manner by stakeholders. Thus, when used properly, clicker technology is well suited to extension as a program evaluation tool, and in particular an effective means by which to track short-term outcomes

The HIV treatment cascade in acutely infected people: informing global guidelines

Acute and early HIV (AHI) is a pivotal time during HIV infection, yet there remain major shortfalls in diagnosis, linkage to care, and antiretroviral therapy (ART) initiation during AHI. We introduce an AHI-specific cascade, review recent evidence pertaining to the unique challenges of AHI, and discuss strategies for improving individual and public health outcomes

Monomeric PcrA helicase processively unwinds plasmid lengths of DNA in the presence of the initiator protein RepD

The helicase PcrA unwinds DNA during asymmetric replication of plasmids, acting with an initiator protein, in our case RepD. Detailed kinetics of PcrA activity were measured using bulk solution and a single-molecule imaging technique to investigate the oligomeric state of the active helicase complex, its processivity and the mechanism of unwinding. By tethering either DNA or PcrA to a microscope coverslip surface, unwinding of both linear and natural circular plasmid DNA by PcrA/RepD was followed in real-time using total internal reflection fluorescence microscopy. Visualization was achieved using a fluorescent single-stranded DNA-binding protein. The single-molecule data show that PcrA, in combination with RepD, can unwind plasmid lengths of DNA in a single run, and that PcrA is active as a monomer. Although the average rate of unwinding was similar in single-molecule and bulk solution assays, the single-molecule experiments revealed a wide distribution of unwinding speeds by different molecules. The average rate of unwinding was several-fold slower than the PcrA translocation rate on single-stranded DNA, suggesting that DNA unwinding may proceed via a partially passive mechanism. However, the fastest dsDNA unwinding rates measured in the single-molecule unwinding assays approached the PcrA translocation speed measured on ssDNA

Evaluating the benefits of incorporating traditional birth attendants in HIV Prevention of Mother to Child Transmission service delivery in Lilongwe, Malawi

The objective of our intervention was to examine the benefits of incorporating traditional birth attendants (TBA) in HIV Prevention of Mother to Child Transmission (PMTCT) service delivery. We developed a training curriculum for TBAs related to PMTCT and current TBA roles in Malawi. Fourteen TBAs and seven TBA assistants serving 4 urban health centre catchment areas were assessed, trained and supervised. Focus group discussions with the TBAs were conducted after implementation of the program. From March 2008 to August 2009, a total of 4017 pregnant women visited TBAs, out of which 2133 (53.1%) were directly referred to health facilities and 1,884 (46.9%) women delivered at TBAs and subsequently referred. 168 HIV positive women were identified by TBAs. Of these, 86/168 (51.2%) women received nevirapine and 46/168 (27.4%) HIV exposed infants received nevirapine. The challenges in providing PMTCT services included lack of transportation for referrals and absence of a reporting system to confirm the woman’s arrival at the health center. Non-disclosure of HIV status by patients to the TBAs resulted in inability to assist nevirapine uptake. TBAs, when trained and well-supervised, can supplement efforts to provide PMTCT services in communities