Venulo-arteriolar communication and propagated response

The effect of microinjection of norepinephrine (10^–5 M) into precapillary microvessels of the rat mesentery was studied using intravital microscopy. Upon application, in 29 out of 40 cases (73%) flow ceased at the site of drug application, although in most cases the precapillary microvessels themselves did not show a diameter change due to a lack of smooth muscle cells as confirmed by transmission electron microscopy. In 17 out of the 29 cases with flow cessation (59%), an intimate contact between the venule draining the site of application and the supplying arteriole was found. Initial constriction was seen at the site where the venule crossed the arteriole. Constriction propagated both up- and downstream along the arteriole, and also across arteriolo-arteriolar arcades. Arteriolar constriction could be abolished by intentionally occluding the venule draining the norepinephrine solution. It is proposed that venuloarteriolar contacts and propagated vasomotor response may contribute to local blood flow regulation by providing a feedback loop between tissue capillaries and resistance arterioles. In three complete mesenteric microvessel networks, the arterioles (n=34) supplying 273 out of 401 capillaries (68%) were in close proximity to venules draining these same capillaries. Each of these arterioles served, on average, 43 capillaries, showing a bimodal distribution with peaks at 4 to 16 and at 64 to 256 capillaries. On average, 62% of all capillaries drained by a given venule crossing an arteriole originated from this very arteriole, indicating a reasonably effective feedback.     

Treatment of mixed bipolar states

Mixed bipolar states are associated with more severe symptoms and outcome. Our aim is to review the literature examining their treatment. We conducted a literature search of randomized clinical studies and post-hoc analyses on mixed bipolar states' treatment. Remarkably, there is only one double-blind, placebo-controlled trial, recruiting a mixed episode cohort, and one post-hoc analysis of this trial, while most data come from post-hoc analyses of trials including both manic and mixed patients. Improvement of manic symptoms in mixed episodes is similar to that seen in pure manic episodes and independent of baseline depressive features. The magnitude of response to manic symptoms' treatment probably exceeds that of depressive symptoms, which appear to resolve later. Valproate and carbamazepine are effective in acute mixed episodes, but the efficacy of lithium appears questionable. Atypical antipsychotic monotherapy improves both manic and depressive symptoms. Mood-stabilizer-atypical antipsychotic combination increases this effect. Atypical antipsychotic-antidepressant combination against acute mixed depression does not increase the risk for mania, although its superior efficacy vs. atypical antipsychotic monotherapy cannot be supported by current data. As regards prophylaxis, atypical antipsychotic monotherapy is associated with a lower incidence of and a longer time to relapse of any kind. The augmentation of lithium or divalproex with atypical antipsychotics increases prophylactic efficacy. Lithium or divalproex monotherapy have not been associated with significant prophylactic benefits following mixed mania. New, randomized prospective trials involving homogeneous cohorts of mixed bipolar patients are needed in order to delineate the appropriate pharmacological treatment of mixed states.     

Duration of the A(H)–A(Md) interval predicts occurrence of AV-block after radiofrequency ablation of the slow pathway

Purpose  

Modification of the slow pathway (SP) of the atrio-ventricular node by radiofrequency ablation is the most effective treatment to cure AV nodal reentry tachycardia (AVNRT). However, this therapy may be complicated by AV-block (AVB). We sought to evaluate the predictive value of the A(H)–A(Md) interval—the electrical delay between atrial signals on the His- and the ablation-catheter—upon development of AVB during SP ablation.     

Increased brainstem volume in panic disorder: a voxel-based morphometric study

Neurocircuitry models of panic disorder have hypothesized that the panic attack itself stems from loci in the brainstem including the ascending reticular system and respiratory and cardiovascular control centers. Voxel-based morphometry with acobian modulation was used to examine gray matter volume changes in 10 panic disorder patients and 23 healthy controls. The panic disorder patients had a relatively increased gray matter volume in the midbrain and rostral pons of the brainstem. Increased ventral hippocampal and decreased regional prefrontal cortex volumes were also noted at a lower significance threshold. This finding has implications for pathophysiologic models of panic disorder, and provides structural evidence for the role of the brainstem in neurocircuitry models of panic disorder.     

Assessment without action; a randomised evaluation of the interRAI home care compared to a national assessment tool on identification of needs and service provision for older people in New Zealand

Comprehensive geriatric assessment (CGA) is considered the cornerstone of good practice, as it identifies need across multiple domains such as social, physical and psychological. The interRAI home care (interRAI‐HC), probably the most well‐researched and supported community‐based CGA has been implemented globally, often at considerable expense. Policy‐makers, managers and clinicians anticipate significant gains in health outcomes following such investment; however, the implementation of CGA is often undertaken in the absence of community service development. This study sought to compare the interRAI‐HC with an existing CGA [the Support Needs Assessment (SNA)] in community‐dwelling older people. A randomised controlled trial was undertaken from January 2006 to January 2007 comparing the interRAI‐HC and the SNA in 316 people (65+) referred for assessment of needs with follow‐up at 1 and 4 months. Outcomes included health‐related quality of life, physical function, social support, cognitive status, mood and health service usage as well as identified need. The study found that significantly more support needs were identified using the interRAI‐HC compared to the SNA. More social and carer support were recommended by SNA and more rehabilitation and preventive health screens were recommended by interRAI‐HC. Despite these differences, the mean healthcare use was similar at 4 months, although interRAI‐HC participants had more Emergency Department presentations and hospital admissions. No statistically significant differences between groups were reported in terms of outcomes. In conclusion, the interRAI‐HC was found to identify more unmet support needs than the SNA though resulted in no favourable outcomes for the older person or their carer. The study highlights the need to invest attention around the service context to maximise outcomes based on identified needs.