The baroreceptor reflex and the cardiovascular changes associated with sustained muscular contraction in the cat

Summary In decerebrate unanaesthetised cats the cardiovascular effects of raising the pressure in a blind sac preparation of a carotid sinus on one side were examined at rest and during sustained contractions of hind-limb muscles. During a tetanic contraction the absolute value of the blood pressure and heart-rate components of the baroreceptor reflex response were not significantly changed from those at rest. The curve relating heart-rate and mean blood pressure, during carotid sinus distension, was similar at rest and when the muscles of the hind-limb were contracting tetanically, although each value of heart-rate was greater, suggesting a resetting of the baroreceptor reflex. By contrast, in the same experiments, suppression of the baroreceptor reflex changes in heart-rate and blood pressure could be demonstrated during the increases of blood pressure and heart-rate elicited by electrical stimulation of limb nerve. It was concluded that the increases in blood pressure and heart-rate elicited by the afferent discharge from muscles during sustained contraction are buffered to some extent by the baroreceptors, though their inhibitory effect is incomplete under these conditions.     

The pontomedullary area integrating the defence reaction in the cat and its influence on muscle blood flow

1. In anaesthetized cats the effects were investigated of electrical stimulation of regions in the caudal mesencephalon, pons and medulla on muscle blood flow, skin blood flow and arterial blood pressure.2. It was found that within the dorsal part of the well known pressor area there is a narrow strip, 2.5 mm lateral from the mid line, starting ventral to the inferior colliculus and ending in the medulla close to the floor of the IV ventricle, from which vasodilatation in skeletal muscles is selectively obtained. This strip is quite separate from the more ventral, efferent pathway for active vasodilatation running from the hypothalamic and rostral mesencephalic ;defence centre'.3. As in the case of the hypothalamic and rostral mesencephalic ;defence centre', the muscle vasodilatation obtained from the caudal strip is accompanied not only by a rise of arterial blood pressure, but also by tachycardia, vasoconstriction in the skin, pupillary dilatation and piloerection.4. Stimulation, restricted to the caudal strip, via implanted electrodes in unanaesthetized animals, produced a behavioural response resembling the defence reaction. The strip, therefore, is probably a caudal extension of the ;defence centre'.5. Unlike the vasodilatation elicited from the more rostral part of the ;defence centre' in the hypothalamus and mesencephalon, the muscle vasodilatation obtained on stimulation of the caudal strip was resistant to atropine, but was blocked by guanethidine.6. It is suggested that during naturally occurring defence reactions in the normal animal the ponto-medullary area is activated together with the hypothalamo-mesencephalic area, inhibition of vasoconstrictor tone then accompanying activation of the vasodilator nerve fibres in skeletal muscle.     

Social–Emotional Profiles of PTSD,Complex PTSD,and Borderline Personality Disorder Among Racially and Ethnically Diverse Young Adults: A Latent Class Analysis

The debate around the construct validity of complex posttraumatic stress disorder (CPTSD) has begun to examine whether CPTSD diverges from posttraumatic stress disorder (PTSD) when it co‐occurs with the diagnosis of borderline personality disorder (BPD). The present study (a) examined the construct validity of CPTSD through a latent class analysis of a non–treatment‐seeking sample of young trauma‐exposed adults and (b) characterized each class in terms of trauma characteristics, social emotions (e.g., shame, guilt, blame), and interpersonal functioning. A total of 23 dichotomized survey items were chosen to represent the symptoms of PTSD, CPTSD, and BPD and administered to 197 trauma‐exposed participants. Fit statistics compared models with 2–4 latent classes. The four‐class model showed the best fit statistics and clinical interpretability. Classes included a “high PTSD+CPTSD+BPD” class, characterized by high‐level endorsement of all symptoms for the three diagnoses; a “moderate PTSD+CPTSD+BPD” class, characterized by endorsement of some symptoms across all three diagnoses; a “PTSD” class, characterized by endorsement of the ICD‐11 PTSD criteria; and a “healthy” class, characterized by low symptom endorsement overall. Pairwise comparisons showed individuals in the high PTSD+CPTSD+BPD class to have the highest levels of psychological distress, traumatic event history, adverse childhood experiences, and PTSD symptoms. Shame was the only social emotion to significantly differ between the classes, p = .002, η² = .16. The findings diverge from the literature, indicating an overlap of PTSD, CPTSD, and BPD symptoms in a non–treatment‐seeking community sample. Further, shame may be a central emotion that differentiates between presentation severities following trauma exposure.     

ASO Author Reflections: Geographic Disparities in Referral and Oncologic Outcomes in Intrahepatic Cholangiocarcinoma

Annals of Surgical Oncology -     

Measurement of voltage-gated potassium currents in identified spinally-projecting sympathetic neurones of the paraventricular nucleus

The paraventricular nucleus (PVN) of the hypothalamus modulates cardiovascular function via a sub-population of neurones which project directly to sympathetic centres of the spinal cord. Identification and patch-clamp recording from these neurones is difficult, however, because of the complex organisation and neuronal heterogeneity of the PVN. We report here on methods for the in vitro recording of voltage-gated potassium channel (K(V)) currents from those neurones within the PVN which project to the intermediolateral column of the rat spinal cord, and are believed to directly modulate cardiovascular function. We show K(V) channel currents of spinally projecting neurones to be slowly inactivating (tau > 100 ms) and weakly sensitive to TEA (K(d)>10 mM). These methods will be useful for the study of K(V) and other ion channel modulation in spinally projecting neurones of the PVN.     

Burnout and well‐being in otolaryngology trainees: A systematic review

ObjectiveTo comprehensively review the recent published literature to characterize current trends of burnout and well‐being among otolaryngology trainees.MethodsStudy design: systematic review and meta‐analysis. A comprehensive literature review from 2000 to 2021 of studies related to otolaryngology resident burnout and well‐being, as well as the general topic of well‐being among surgical residents was completed. All included studies were summarized qualitatively. For the quantitative analysis, only articles reporting a Maslach burnout inventory (MBI), modified MBI or Mini‐Z‐ Burnout assessment were included.ResultsTwenty‐five articles were included in the qualitative summary and nine articles in the quantitative analysis. In the qualitative summary, trainees were reported to have increased levels of distress and emotional hardening compared to attending otolaryngologists. Total hours worked per week and female gender were associated with worsened well‐being. Residency program strategies to improve trainee well‐being include program‐sponsored wellness activities, dedicated wellness champions, and assistance with clerical burden. Implementation of protected nonclinical time has been shown to decrease burnout and increase well‐being among trainees. Moreover, formal trainee mentorship programs have also been shown to reduce trainee burnout and stress. In the quantitative analysis, rates of trainee burnout ranged from 29.7% to 86% with an overall trend towards reduced rates of burnout from 2006 to 2021. Utilizing a weighted average, the overall burnout among otolaryngology residents was 58.6%.ConclusionsRates of burnout remain high among otolaryngology trainees. Implementing formal mentorship programs and providing protected time during regular work hours appear to be effective tools to improve resident well‐being.     

Central pathways of some autonomic reflex discharges

1. Electrical stimulation of spinal sensory nerves evoked discharges in inferior cardiac and renal nerves. In the anaesthetized cat both an early and a late response could be recorded in each nerve.2. For any one afferent input the central delay of the late cardiac nerve response was significantly less than that of the late renal nerve response. The central delay of the early responses was similar for both nerves. In the spinal cat only the early response was present.3. Cooling the floor of the 4th ventricle abolished the late responses in renal nerves, but left reflex volleys in white rami and intercostal nerves unchanged.4. Stimulation in the brain stem evoked responses in both cardiac and renal nerves which had a shorter latency than the reflexes evoked in these nerves by stimulating dorsal roots.5. The late responses could be abolished by lesions in the cervical spinal cord.6. Such evidence led to the conclusion that there are two pathways for reflex discharge into inferior cardiac and renal nerves, one involving a supraspinal relay and the other confined to the spinal cord.     

Changing Physical Activity Behavior in People With Multiple Sclerosis: A Systematic Review and Meta-Analysis

Objectives

To (1) systematically review the literature on behavioral interventions for people with multiple sclerosis (MS) that aim to change physical activity (PA) behavior; and (2) explore whether these interventions are clinically effective in improving PA, are theory based, and use established behavior change techniques (BCTs).

Automatic facial responses to briefly presented emotional stimuli in autism spectrum disorder

Emotion processing, including automatic facial mimicry, plays an important role in social reciprocity. Disruptions in these processes have implications for individuals with impaired social functioning, such as autism spectrum disorders (ASDs). Past research has demonstrated that ASDs are impaired in the recognition of briefly presented emotions and display atypical mimicry of emotions presented for protracted duration. Mimicry (electromyography; EMG) of briefly presented emotions was investigated in adults with ASDs. Concurrent measures of skin conductance and cardiac responses were used as markers of orientation and stimulus detection, respectively. A backward masking task was employed whereby the emotional face (happy, angry) was presented for 30 ms followed by a neutral face “mask”. An implicit comparison task required rapid gender identification. The ASD group failed to differentiate by valence in their EMG (zygomaticus, corrugator) and demonstrated atypical pre- and post-stimulus arousal. These findings may provide a potential mechanism for marked deficits in social reciprocity.