Protein kinases in vascular smooth muscle tone--role in the pulmonary vasculature and hypoxic pulmonary vasoconstriction

Hypoxic pulmonary vasoconstriction (HPV) is an adaptive mechanism that in the normal animal diverts blood away from poorly ventilated areas of the lung, thereby maintaining optimal ventilation-perfusion matching. In global hypoxia however, such as in respiratory disease or at altitude, it causes detrimental increases in pulmonary vascular resistance and pulmonary artery (PA) pressure. The precise intracellular pathways and mechanisms underlying HPV remain unclear, although it is now recognised that both an elevation in smooth muscle intracellular [Ca2+] and a concomitant increase in Ca2+ sensitivity are involved. Several key intracellular protein kinases have been proposed as components of the signal transduction pathways leading to development of HPV, specifically Rho kinase, non-receptor tyrosine kinases (NRTK), p38 mitogen activated protein (MAP) kinase, and protein kinase C (PKC). All of these have been implicated to a greater or lesser extent in pathways leading to Ca2+ sensitisation, and in some cases regulation of intracellular [Ca2+] as well. In this article, we review the role of these key protein kinases in the regulation of vascular smooth muscle (VSM) constriction, applying what is known in the systemic circulation to the pulmonary circulation and HPV. We conclude that the strongest evidence for direct involvement of protein kinases in the mechanisms of HPV concerns a central role for Rho kinase in Ca2+ sensitisation, and a potential role for Src-family kinases in both modulation of Ca2+ entry via capacitative Ca2+ entry (CCE) and activation of Rho kinase, though others are likely to have indirect or modulatory influences. In addition, we speculate that Src family kinases may provide a central interface between the proposed hypoxia-induced generation of reactive oxygen species by mitochondria and both the elevation in intracellular [Ca2+] and Rho kinase mediated Ca2+ sensitisation.     

Development of a sensitive PCR-dot blot assay to supplement serological tests for diagnosing Lyme disease

Laboratory diagnosis of Lyme disease is difficult and presently dependent on detecting Borrelia burgdorferi-specific antibodies in patient serum with the disadvantage that the immune response to B. burgdorferi can be weak or variable, or alternatively, the slow and inefficient culture confirmation of B. burgdorferi. PCR tests have previously shown poor sensitivity and are not routinely used for diagnosis. We developed a sensitive and specific Lyme Multiplex PCR-dot blot assay (LM-PCR assay) applicable to blood and urine samples to supplement western blot (WB) serological tests for detecting B. burgdorferi infection. The LM-PCR assay utilizes specific DNA hybridization to purify B. burgdorferi DNA followed by PCR amplification of flagellin and OspA gene fragments and their detection by southern dot blots. Results of the assay on 107 and 402 clinical samples from patients with suspected Lyme disease from Houston, Texas or received at the IGeneX laboratory in Palo Alto, California, respectively, were analyzed together with WB findings. The LM-PCR assay was highly specific for B. burgdorferi. In the Texas samples, 23 (21.5%) patients antibody-negative in WB assays by current US Centers for Disease Control (CDC) recommended criteria were positive by LM-PCR performed on urine, serum or whole blood samples. With IGeneX samples, of the 402 LM-PCR positive blood samples, only 70 met the CDC criteria for positive WBs, while 236 met IGeneX criteria for positive WB. Use of the LM-PCR assay and optimization of current CDC serological criteria can improve the diagnosis of Lyme disease.     

How many cases of disease in a pedigree imply familial disease?

The ability to perform whole‐exome and, increasingly, whole‐genome sequencing on large numbers of individuals has led to increased efforts to identify rare genetic variants that affect the risk of both common and rare diseases. In such applications, it is important to identify families that are segregating the rare variants of interest. For rare diseases or rare familial forms of common diseases, pedigrees with multiple affected members are clearly harbouring risk variants. For more common diseases, however, it may be unclear whether a family with a few affected members is segregating a familial disease, is the result of multiple sporadic cases, or is a mixture of familial cases and phenocopies. We provide calculations for the probability that a family is harbouring familial disease, presented in general terms that admit working guidelines for selecting families for current sequencing studies. Using examples motivated by our own studies of thyroid cancer and published studies of colorectal cancer, we show that for common diseases, families with exactly two affected first‐degree relatives have only a moderate probability of segregating familial disease, but this probability is higher for families with three or more affected relatives, and those families should therefore be prioritised in sequencing studies.     

Human mast cells present antigen to autologous CD4+ T cells

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Comparison of a new mineral based hemostatic agent to a commercially available granular zeolite agent for hemostasis in a swine model of lethal extremity arterial hemorrhage

BACKGROUND: Gaining hemostatic control of vascular injuries sustained in combat using topical agents remains a challenge. We previously developed a new hemostatic agent consisting of a granular combination of a smectite mineral and a superabsorbent polymer (WoundStattrade mark; WS) which demonstrated the ability to stop high pressure bleeding. We have since modified WS to contain only the smectite mineral and compared the performance of WS to QuikClot'strade mark zeolite granules (QCG) in a lethal vascular injury model. METHODS: Fourteen (seven per group) anesthetized swine (35-44kg) had a lethal femoral artery injury produced by creating a 6mm arteriotomy in the vessel. After 45s of hemorrhage, animals were randomized to be treated with either WS or QCG for 3min. A second application was provided if hemostasis failed. Fluid resuscitation was begun at the time of application to achieve a mean arterial blood pressure of 65mmHg. Animals were observed for 120min or until death. Primary endpoints were survival, survival time, post-treatment blood loss, and resuscitation fluid volume. RESULTS: WS resulted in 100% survival to 120min. No animal in the QCG group survived (p=0.0005). Survival times for WS animals were significantly greater compared to QCG (p=0.0001). Post-treatment blood loss (p=0.0043) and post-resuscitation fluid volume (p=0.0043) was significantly less for animals treated with WS compared to QCG. CONCLUSION: WS consisting of just the smectite mineral was superior to QCG tested in this model. Additional study is warranted to determine its potential for use in combat and civilian trauma.     

Defining Resilience in Families Living with Neurodevelopmental Disorder: A Preliminary Examination of Walsh’s Framework

Family interaction and support play a critical role in raising a child with a neurodevelopmental disorder (NDD) of brain function and growth. Although the negative effects of NDD on the family, including parental distress, have been widely studied less is known about the structure of resilience in these families, or their capacity to cope. The current study attempts to quantitatively define this complex construct, with reference to Walsh’s (2003) Family Resilience Framework. Results from an online survey of 155 female caregivers of children diagnosed with an autism spectrum disorder, intellectual disability, specific learning or communication difficulty highlighted the individual and combined contribution of three family processes—belief systems, organisational patterns and communication skills—to resilience. Regression analysis revealed that parental distress, directly associated with problematic communication patterns, was a significant (p?<?.01) impediment to family resilience. Facilitators of resilience included positive belief systems (i.e. positive perceptions of a child’s disability and general outlook) along with a parental organisational style characterised by high nurturing. However, the combined contribution of these variables accounted for only 35 % of the variance in resilience scores, suggesting that further work is needed to operationalise the resilience process. Large-scale and longitudinal data will also help to determine resilience trajectories over time and in different family contexts.