The effects of messaging on long COVID expectations: An online experiment

OBJECTIVE

We examined whether varying information about long COVID would affect expectations about the illness.

METHOD

In October 2021, we conducted a 2 (Illness Description: long COVID vs. ongoing COVID-19 recovery) × 2 (Symptom Uncertainty: uncertainty emphasized vs. not emphasized) × 2 (Efficacy of Support: enhanced vs. basic support) between-subjects randomized online experimental study. Participants (N = 1,110) were presented with a scenario describing a positive COVID-19 test result, followed by one of eight scenarios describing a long COVID diagnosis and then completed outcome measures of illness expectations including: symptom severity, symptom duration, quality of life, personal control, treatment control, and illness coherence.

RESULTS

We ran a series of 2 × 2 × 2 ANOVAs on the outcome variables. We found a main effect of illness description: individuals reported longer symptom duration and less illness coherence when the illness was described as long COVID (compared to ongoing COVID-19 recovery). There was a main effect of symptom uncertainty: when uncertainty was emphasized, participants reported longer expected symptom duration (p < .001), less treatment control (p = .031), and less illness coherence (p < .001) than when uncertainty was not emphasized. There was a main effect of efficacy of support: participants reported higher personal control (p = .004) and higher treatment control (p = .037) when support was enhanced (compared to basic support).

CONCLUSIONS

Communications around long COVID should avoid emphasizing symptom uncertainty and aim to provide people with access to additional support and information on how they can facilitate their recovery. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Attitudes towards coronavirus (COVID-19) vaccine and sources of information across diverse ethnic groups in the UK: a qualitative study from June to October 2020

OBJECTIVES

Across diverse ethnic groups in the UK, explore attitudes and intentions towards COVID-19 vaccination and sources of COVID-19 information.

DESIGN

Remote qualitative interviews and focus groups (FGs) conducted June-October 2020 before UK COVID-19 vaccine approval. Data were transcribed and analysed through inductive thematic analysis and mapped to the Theoretical Domains Framework.

SETTING

England and Wales.

PARTICIPANTS

100 participants from 19 self-identified ethnic groups.

RESULTS

Mistrust and doubt were reported across ethnic groups. Many participants shared concerns about perceived lack of information about COVID-19 vaccine safety and efficacy. There were differences within each ethnic group, with factors such as occupation and perceived health status influencing intention to accept a vaccine once made available. Across ethnic groups, participants believed that public contact occupations, older adults and vulnerable groups should be prioritised for vaccination. Perceived risk, social influences, occupation, age, comorbidities and engagement with healthcare influenced participants' intentions to accept vaccination once available. All Jewish FG participants intended to accept, while all Traveller FG participants indicated they probably would not.Facilitators to COVID-19 vaccine uptake across ethnic groups included: desire to return to normality and protect health and well-being; perceived higher risk of infection; evidence of vaccine safety and efficacy; vaccine availability and accessibility.COVID-19 information sources were influenced by social factors and included: friends and family; media and news outlets; research literature; and culture and religion. Participants across most different ethnic groups were concerned about misinformation or had negative attitudes towards the media.

CONCLUSIONS

During vaccination rollout, including boosters, commissioners and providers should provide accurate information, authentic community outreach and use appropriate channels to disseminate information and counter misinformation. Adopting a context-specific approach to vaccine resources, interventions and policies and empowering communities has potential to increase trust in the programme.

Public views of and reactions to the COVID-19 pandemic in England: a qualitative study with diverse ethnicities

OBJECTIVES

To explore public reactions to the COVID-19 pandemic across diverse ethnic groups.

DESIGN

Remote qualitative interviews and focus groups in English or Punjabi. Data were transcribed and analysed through inductive thematic analysis.

SETTING

England and Wales, June to October 2020.

PARTICIPANTS

100 participants from 19 diverse 'self-identified' ethnic groups.

RESULTS

Dismay, frustration and altruism were reported across all ethnic groups during the first 6-9 months of the COVID-19 pandemic. Dismay was caused by participants' reported individual, family and community risks, and loss of support networks. Frustration was caused by reported lack of recognition of the efforts of ethnic minority groups (EMGs), inaction by government to address COVID-19 and inequalities, rule breaking by government advisors, changing government rules around: border controls, personal protective equipment, social distancing, eating out, and perceived poor communication around COVID-19 and the Public Health England COVID-19 disparities report (leading to reported increased racism and social isolation). Altruism was felt by all, in the resilience of National Health Service (NHS) staff and their communities and families pulling together. Data, participants' suggested actions and the behaviour change wheel informed suggested interventions and policies to help control COVID-19.

CONCLUSION

To improve trust and compliance future reports or guidance should clearly explain any stated differences in health outcomes by ethnicity or other risk group, including specific messages for these groups and concrete actions to minimise any risks. Messaging should reflect the uncertainty in data or advice and how guidance may change going forward as new evidence becomes available. A contingency plan is needed to mitigate the impact of COVID-19 across all communities including EMGs, the vulnerable and socially disadvantaged individuals, in preparation for any rise in cases and for future pandemics. Equality across ethnicities for healthcare is essential, and the NHS and local communities will need to be supported to attain this.

Exploring vaccine hesitancy in care home employees in North West England: a qualitative study

OBJECTIVES

Care homes have experienced a high number of COVID-19 outbreaks, and it is therefore important for care home employees to receive the COVID-19 vaccine. However, there is high vaccine hesitancy among this group. We aimed to understand barriers and facilitators to getting the COVID-19 vaccine, as well as views on potential mandatory vaccination policies.

DESIGN

Semi-structured interviews.

SETTING

Care home employees in North West England. Interviews conducted in April 2021.

PARTICIPANTS

10 care home employees (aged 25-61 years) in the North West, who had been invited to have, but not received the COVID-19 vaccine.

RESULTS

We analysed the interviews using a framework analysis. Our analysis identified eight themes: perceived risk of COVID-19, effectiveness of the vaccine, concerns about the vaccine, mistrust in authorities, facilitators to getting the vaccine, views on mandatory vaccinations, negative experiences of care work during the COVID-19 pandemic, and communication challenges.

CONCLUSIONS

Making COVID-19 vaccination a condition of deployment may not result in increased willingness to get the COVID-19 vaccination, with most care home employees in this study favouring leaving their job rather than getting vaccinated. At a time when many care workers already had negative experiences during the pandemic due to perceived negative judgement from others and a perceived lack of support facing care home employees, policies that require vaccination as a condition of deployment were not positively received.

Impact of residual risk messaging to reduce false reassurance following test-negative results from asymptomatic coronavirus (SARS-CoV-2) testing: an online experimental study of a hypothetical test

OBJECTIVES

Individuals who receive a negative lateral flow coronavirus test result may misunderstand it as meaning 'no risk of infectiousness', giving false reassurance. This experiment tested the impact of adding information to negative test result messages about residual risk and the need to continue protective behaviours.

DESIGN

4 (residual risk) × 2 (post-test result behaviours) between-subjects design.

SETTING

Online.

PARTICIPANTS

1200 adults from a representative UK sample recruited via Prolific (12-15 March 2021).

INTERVENTIONS

Participants were randomly allocated to one of eight messages. Residual risk messages were: (1) 'Your coronavirus test result is negative' (control); (2) message 1 plus 'It's likely you were not infectious when the test was done' (current NHS Test & Trace (T&T); (3) message 2 plus 'But there is still a chance you may be infectious' (elaborated NHS T&T); and (4) message 3 plus infographic depicting residual risk (elaborated NHS T&T+infographic). Each message contained either no additional information or information about the need to continue following guidelines and protective behaviours.

OUTCOME MEASURES

(1) Proportion understanding residual risk of infectiousness and (2) likelihood of engaging in protective behaviours (scales 1-7).

RESULTS

The control message decreased understanding relative to the current NHS T&T message: 54% versus 71% (Adjusted Odds Ratio (AOR)=0.56 95% CI 0.34 to 0.95, p=0.030). Understanding increased with the elaborated NHS T&T (89%; AOR=3.25 95% CI 1.64 to 6.42, p=0.001) and elaborated NHS T&T+infographic (91%; AOR=5.16 95% CI 2.47 to 10.82, p<0.001) compared with current NHS T&T message. Likelihood of engaging in protective behaviours was unaffected by information (AOR=1.11 95% CI 0.69 to 1.80, χ²(1)=0.18, p=0.669), being high (M=6.4, SD=0.9) across the sample.

CONCLUSIONS

A considerable proportion of participants misunderstood the residual risk following a negative test result. The addition of a single sentence ('But there is still a chance you may be infectious') to current NHS T&T wording increased understanding of residual risk.

TRIAL REGISTRATION NUMBER

OSF: https://osf.io/byfz3/.

Impact of residual risk messaging to reduce false reassurance following test-negative results from asymptomatic coronavirus (SARS-CoV-2) testing: an online experimental study of a hypothetical test

OBJECTIVES

Individuals who receive a negative lateral flow coronavirus test result may misunderstand it as meaning 'no risk of infectiousness', giving false reassurance. This experiment tested the impact of adding information to negative test result messages about residual risk and the need to continue protective behaviours.

DESIGN

4 (residual risk) × 2 (post-test result behaviours) between-subjects design.

SETTING

Online.

PARTICIPANTS

1200 adults from a representative UK sample recruited via Prolific (12-15 March 2021).

INTERVENTIONS

Participants were randomly allocated to one of eight messages. Residual risk messages were: (1) 'Your coronavirus test result is negative' (control); (2) message 1 plus 'It's likely you were not infectious when the test was done' (current NHS Test & Trace (T&T); (3) message 2 plus 'But there is still a chance you may be infectious' (elaborated NHS T&T); and (4) message 3 plus infographic depicting residual risk (elaborated NHS T&T+infographic). Each message contained either no additional information or information about the need to continue following guidelines and protective behaviours.

OUTCOME MEASURES

(1) Proportion understanding residual risk of infectiousness and (2) likelihood of engaging in protective behaviours (scales 1-7).

RESULTS

The control message decreased understanding relative to the current NHS T&T message: 54% versus 71% (Adjusted Odds Ratio (AOR)=0.56 95% CI 0.34 to 0.95, p=0.030). Understanding increased with the elaborated NHS T&T (89%; AOR=3.25 95% CI 1.64 to 6.42, p=0.001) and elaborated NHS T&T+infographic (91%; AOR=5.16 95% CI 2.47 to 10.82, p<0.001) compared with current NHS T&T message. Likelihood of engaging in protective behaviours was unaffected by information (AOR=1.11 95% CI 0.69 to 1.80, χ²(1)=0.18, p=0.669), being high (M=6.4, SD=0.9) across the sample.

CONCLUSIONS

A considerable proportion of participants misunderstood the residual risk following a negative test result. The addition of a single sentence ('But there is still a chance you may be infectious') to current NHS T&T wording increased understanding of residual risk.

TRIAL REGISTRATION NUMBER

OSF: https://osf.io/byfz3/.

Self-Reported Antimicrobial Stewardship Practices in Primary Care Using the TARGET Antibiotics Self-Assessment Tool

The self-assessment tool (SAT) is a 16-question self-report of antimicrobial stewardship practices in primary care, available in the TARGET (Treat Antibiotics Responsibly, Guidance Education and Tools) Antibiotics Toolkit. This study analysed responses to the SAT and compared them to previous SAT data (2014-2016). Data from June 2016 to September 2019 were anonymised and analysed using Microsoft Excel and STATA 15. Clinicians reported engaging in positive antimicrobial stewardship (AMS) practices including using antibiotic guidance to inform treatment decisions (98%, 98% 2014-2016), discussing antibiotic prescribing within the practice (73%, 67% 2014-2016), using patient-facing resources (94%, 71% 2014-2016), conducting antibiotic audits in the last two years (98%, 45% 2014-2016), keeping written records and action plans (81%, 62% 2014-2016), using back-up prescribing (99%, 94% 2014-2016) and using clinical coding (80%, 75% 2014-2016). Areas for improvement include developing strategies to avoid patients reconsulting to obtain antibiotics (45%, 33% 2014-2016), undertaking infection-related learning (37%, 29% 2014-2016), ensuring all temporary prescribers have access to antibiotic guidance (55%, 63% 2014-2016) and making patient information leaflets easily available during consultations (31%). The findings offer a unique insight into AMS in primary care over time. The SAT gives primary care clinicians and commissioners an opportunity to reflect on their AMS and learning.

Qualitative study using interviews and focus groups to explore the current and potential for antimicrobial stewardship in community pharmacy informed by the Theoretical Domains Framework

OBJECTIVES

Community pharmacists and their staff have the potential to contribute to antimicrobial stewardship (AMS). However, their barriers and opportunities are not well understood. The aim was to investigate the experiences and perceptions of community pharmacists and their teams around AMS to inform intervention development.

DESIGN

Interviews and focus groups were used to explore the views of pharmacists, pharmacy staff, general practitioners (GPs), members of pharmacy organisations and commissioners. The questioning schedule was developed using the Theoretical Domains Framework which helped inform recommendations to facilitate AMS in community pharmacy.

RESULTS

8 GPs, 28 pharmacists, 13 pharmacy staff, 6 representatives from pharmacy organisations in England and Wales, and 2 local stakeholders participated.Knowledge and skills both facilitated or hindered provision of self-care and compliance advice by different grades of pharmacy staff. Some staff were not aware of the impact of giving self-care and compliance advice to help control antimicrobial resistance (AMR). The pharmacy environment created barriers to AMS; this included lack of time of well-qualified staff leading to misinformation from underskilled staff to patients about the need for antibiotics or the need to visit the GP, this was exacerbated by lack of space. AMS activities were limited by absent diagnoses on antibiotic prescriptions.Several pharmacy staff felt that undertaking patient examinations, questioning the rationale for antibiotic prescriptions and performing audits would allow them to provide more tailored AMS advice.

CONCLUSIONS

Interventions are required to overcome a lack of qualified staff, time and space to give patients AMS advice. Staff need to understand how self-care and antibiotic compliance advice can help control AMR. A multifaceted educational intervention including information for staff with feedback about the advice given may help. Indication for a prescription would enable pharmacists to provide more targeted antibiotic advice. Commissioners should consider the pharmacists' role in examining patients, and giving advice about antibiotic prescriptions.

An evaluation of the TARGET (Treat Antibiotics Responsibly; Guidance, Education, Tools) Antibiotics Toolkit to improve antimicrobial stewardship in primary care-is it fit for purpose?

BACKGROUND

The TARGET (Treat Antibiotics Responsibly; Guidance, Education, Tools) Antibiotics Toolkit aims to improve antimicrobial prescribing in primary care through guidance, interactive workshops with action planning, patient facing educational and audit materials.

OBJECTIVE

To explore GPs', nurses' and other stakeholders' views of TARGET.

DESIGN

Mixed methods.

METHOD

In 2014, 40 UK GP staff and 13 stakeholders participated in interviews or focus groups. We analysed data using a thematic framework and normalization process theory (NPT).

RESULTS

Two hundred and sixty-nine workshop participants completed evaluation forms, and 40 GP staff, 4 trainers and 9 relevant stakeholders participated in interviews (29) or focus groups (24). GP staffs were aware of the issues around antimicrobial resistance (AMR) and how it related to their prescribing. Most participants stated that TARGET as a whole was useful. Participants suggested the workshop needed less background on AMR, be centred around clinical cases and allow more action planning time. Participants particularly valued comparison of their practice antibiotic prescribing with others and the TARGET Treating Your Infection leaflet. The leaflet needed greater accessibility via GP computer systems. Due to time, cost, accessibility and competing priorities, many GP staff had not fully utilized all resources, especially the audit and educational materials.

CONCLUSIONS

We found evidence that the workshop is likely to be more acceptable and engaging if based around clinical scenarios, with less on AMR and more time on action planning. Greater promotion of TARGET, through Clinical Commissioning Group's (CCG's) and professional bodies, may improve uptake. Patient facing resources should be made accessible through computer shortcuts built into general practice software.

Self-Assessment of Antimicrobial Stewardship in Primary Care: Self-Reported Practice Using the TARGET Primary Care Self-Assessment Tool

Multifaceted antimicrobial stewardship (AMS) interventions including: antibiotic guidance, reviews of antibiotic use using audits, education, patient facing materials, and self-assessment, are successful in improving antimicrobial use. We aimed to measure the self-reported AMS activity of staff completing a self-assessment tool (SAT). The Royal College of General Practitioners (RCGP)/Public Health England (PHE) SAT enables participants considering an AMS eLearning course to answer 12 short questions about their AMS activities. Questions cover guidance, audit, and reflection about antibiotic use, patient facing materials, and education. Responses are recorded digitally. Data were collated, anonymised, and exported into Microsoft Excel. Between November 2014 and June 2016, 1415 users completed the SAT. Ninety eight percent reported that they used antibiotic guidance for treating common infections and 63% knew this was available to all prescribers. Ninety four percent of GP respondents reported having used delayed prescribing when appropriate, 25% were not using Read codes, and 62% reported undertaking a practice-wide antibiotic audit in the last two years, of which, 77% developed an audit action plan. Twenty nine percent had undertaken other antibiotic-related clinical courses. Fifty six percent reported sharing patient leaflets covering infection. Many prescribers reported undertaking a range of AMS activities. GP practice managers should ensure that all clinicians have access to prescribing guidance. Antibiotic audits should be encouraged to enable GP staff to understand their prescribing behaviour and address gaps in good practice. Prescribers are not making full use of antibiotic prescribing-related training opportunities. Read coding facilitates more accurate auditing and its use by all clinicians should be encouraged.

Muscular torque generation during imposed joint rotation: torque-angle relationships when subjects' only goal is to make a constant effort

It is a reasonable expectation that voluntarily activated spinal motoneurons will be further excited by increases in spindle afferent activity produced by muscle stretch. Human motor behavior attributed to tonic stretch reflexes and to reflexes recruited by relatively slow joint rotation has been reported from several laboratories. We reinvestigated this issue by rotating the elbow joint over the central portion of its range while subjects focused on keeping their elbow flexion effort constant at one of three different levels and made no attempt to control the position, speed or direction of movement of their forearm. There is evidence that subjects' voluntary motor status is constant under these conditions so that any change in torque would be of involuntary origin. On average, torques rose somewhat and then fell as the elbow was flexed through a range of 80 degrees at 10, 20 and 60 degrees/s and a similar pattern occurred during elbow extension; i.e., both concentric and eccentric torque-angle profiles had roughly similar shapes and neither produced consistent stabilizing cross-range stiffness. The negative stiffness (rising torque) during the early part of a concentric movement and the negative stiffness (falling torque) during the later part of an eccentric movement would not have occurred if a stabilizing stretch reflex had been present. Positive stiffness rarely gave rise to torque changes greater than 20% in either individual or cross-subject averaged data. When angular regions of negative stiffness are combined with regions of low positive stiffness (torque change 10% or less), much of the range of motion was not well stabilized, especially during eccentric movements. The sum of the EMGs from biceps brachii, brachioradialis and brachialis showed a pattern opposite to that expected for a stretch reflex; there was an upward trend in the EMG as the elbow was flexed and a downward trend as the elbow was extended. There was little change in the shape of this EMG-angle relationship with either direction or velocity. The individual EMG-angle relationships were distinctive for each of these three elbow flexor muscles in four of the six subjects; in the remaining two, biceps was distinctive, but brachioradialis and brachialis appeared to be coupled. Although the EMGs of individual muscles were modulated over the angular range, no consistent stretch reflexes could be seen in the individual records. Thus, we could find no clear evidence for stretch reflex stabilization of human subjects maintaining a constant effort. Rather, muscle torque appears to be reflexly modulated across a much used portion of the elbow's angular range so that any appreciable stabilizing stiffness that is sustained for more than fractions of a second is associated with a change in effort.

Neural gain changes subserving perceptual acuity

When small and large objects of equal weight are lifted, the small object feels heavier than the large one (the size-weight illusion) and requires more effort to lift (the size-effort illusion). It has been suggested that these illusions result from neural gain changes designed to maintain acuity under different working conditions. If this suggestion is correct, a given mass should produce a larger increase in perceived weight or effort when added to the small object. This was found to be the case.

Perceptions of effort and heaviness during fatigue and during the size-weight illusion

Previous work has shown that force perception and the sense of motor effort are different attributes of sensorimotor function. This study explores the hypothesis that one reason force and effort perceptions are distinct is to inform an individual of impaired motor function when muscular force lags effort. This hypothesis predicts that effort and force perceptions will dissociate when motor function is impaired by fatigue but not during the size-weight illusion. All subjects reported a distinct increase in effort when lifting a standard test weight as fatigue developed. When fatigue was sufficiently marked so that they could barely lift the test weight, they rated their effort as similar to that required to lift a maximal weight in the unfatigued state. The perceived heaviness of the test weight also increased as fatigue developed, but this fatigue-weight illusion was smaller than the increase in effort for all subjects and displayed greater variability. In contrast, both the perceived weight of a small object and the effort required to lift it increased in parallel when small and large objects were lifted sequentially. The size-weight and size-effort illusions appear to be examples of a common phenomenon in which perceptual experience is rescaled to maintain acuity under different working conditions. The fatigue-weight illusion also has the effect of increasing perceptual acuity as the subject's weight lifting range decreases due to fatigue.

Association between eye dominance and training for rifle marksmanship: a pilot study

BACKGROUND

This pilot study was performed to determine the effect, if any, exerted by crossed dominance (contralateral hand and eye dominance) on the ability of novice riflemen to learn how to accurately shoot a rifle.

METHODS

Sighting dominance was used to determine the dominant eye. Hand dominance was determined by the arm used to shoulder the rifle in the shooting position. Subjects were 308 military recruits at the Fort Benning Army Base in Columbus, Georgia, who had undergone basic training in rifle marksmanship. Qualification scores obtained at the base rifle range were used to measure the subjects' ability to learn marksmanship skills.

RESULTS

The subjects with right-hand/right-eye and left-hand/left-eye (uncrossed) dominance had qualification scores that were significantly higher (p = .009) than the subjects with right hand/left-eye and left-hand/right-eye (crossed) dominance. A significantly higher percentage of subjects with uncrossed dominance achieved rifle qualification (86.1 percent) than subjects with crossed dominance (56.5 percent) (p = .000).

CONCLUSIONS

The learning of rifle marksmanship is influenced by eye dominance. Individuals who shoot right handed and are left-eye dominant or who shoot left handed and are right-eye dominant do not learn marksmanship skills as readily as individuals who have matched eye and hand dominance. Since crossed hand and eye dominance can be easily determined, it should be possible to identify cross dominant individuals and provide them with special training so that they can perform at a higher level of skill.

Measurement of coronary blood flow velocity in conscious rats

This study describes a technique for the continuous recording of coronary blood flow velocity (CBV) in conscious unrestrained rats. A pulsed Doppler flow probe consisting of a 1-mm2 crystal mounted in a 4-mm suction cup was positioned over the left coronary artery of pentobarbital sodium-anesthetized rats. The probe was held in place with mild suction and sutured to the surface of the myocardium. Probes were connected to a pulsed Doppler flowmeter, which measures Doppler shift and provides an index of blood flow velocity. While rats were still anesthetized, the measurement of CBV was validated by determining that CBV peaked during diastole and increased in parallel with arterial pressure. Phasic CBV signals obtained in conscious rats were similar to those observed in anesthetized animals. Intravenous infusion of dipyridamole (0.5-3 mg.kg-1 x mg-1) produced a dose-dependent increase in CBV and decrease in coronary vascular resistance in conscious unrestrained rats 7 days after placement of the probe. Light microscopic review of cardiac tissue from instrumented rats revealed minimal epicardial reaction (fibrin deposition) restricted to the immediate area of the probe without distortion of the coronary architecture, edema, inflammation, or necrosis compared with controls. Heart weight-to-body weight ratios of instrumented rats were also not different from those of control rats. This study describes the first technique by which CBV can be measured continuously in chronically instrumented rats.

Characterization of coronary vasoconstriction produced by rostral ventrolateral medulla stimulation in rats

Previous studies have demonstrated that coronary vasoconstriction can be produced by activation of specific central nervous system sites in the cat. The present study was undertaken 1) to develop a rat model for studying central influences on coronary circulation and 2) to utilize this model for characterization of the changes in coronary blood flow (CBF) produced by stimulation of rostral ventrolateral medulla (RVLM). Electrical stimulation of right RVLM in chloralose-anesthetized rats with bilateral vagotomy produced a transient decrease in CBF followed by an increase in CBF concomitant with a decrease in hindquarter blood flow, a pressor response, and tachycardia. After atenolol the tachycardia and increase in CBF were abolished, whereas the decrease in CBF was enhanced and prolonged. Phentolamine (1 mg/kg iv) or removal of the stellate ganglia inhibited the decrease in CBF but did not totally abolish the increase in coronary vascular resistance. Inhibition of nitric oxide synthesis with N-nitro-L-arginine (10 microM/kg iv) enhanced the decrease in CBF produced by stimulation in RVLM. These results indicate that, in rat model, the centrally induced decrease in CBF is 1) mediated by cardiac sympathetic innervation but only partially through alpha-adrenoceptors and 2) enhanced by removal of the inhibitory effect of the endothelium.

Patterns of hemodynamic responses associated with central activation of coronary vasoconstriction

Previous studies in our laboratory have identified several central sites from which coronary vasoconstriction can be elicited by electrical stimulation. The present study was conducted to determine if specific patterns of hemodynamic responses are associated with activation of the coronary vasoconstrictor pathway in the hypothalamus, pons, and medulla. Cats anesthetized with chloralose were instrumented for recording arterial pressure, heart rate, and coronary, femoral, renal, and mesenteric blood flow velocities. After vagotomy and atenolol (1 mg/kg iv), anterior hypothalamus (AHA), parabrachial nucleus (PBN), a site very close to the ventral surface of the pons lateral to the pyramidal tract, and rostral ventrolateral medulla (RVLM) were stimulated electrically. Stimulation produced a decrease in coronary blood flow that was associated with all of the cardiovascular components of the defense reaction, an integrated response that included a decrease in hindquarter vascular resistance (blocked by methyl atropine), increases in renal and mesenteric vascular resistances, and a pressor response, except no change in renal vascular resistance from RVLM. Different patterns of hemodynamic responses were obtained from sites outside the coronary vasoconstrictor areas. From these results we conclude that coronary vasoconstriction is a frequent component of the defense reaction.

Coronary blood flow in rats is dependent on the release of vascular nitric oxide

The present study evaluated the role of nitric oxide (NO) in determining basal coronary vascular tone and the mechanism by which NO regulates coronary blood flow. Sprague-Dawley rats were anesthetized and instrumented for recording arterial pressure (AP), heart rate (HR) and coronary blood flow (CBF; Doppler). In rats without ventricular pacing, N-nitro-L-arginine methyl ester (LNAME) (10 mumol/kg, i.v.), an inhibitor of NO synthesis, produced an increase in AP and a decrease in HR. The LNAME-induced bradycardia was inhibited by sinoaortic denervation. LNAME also produced a reduction in left anterior descending (LAD) CBF. When the same dose of LNAME was administered to a separate group of rats measuring CBF in the right coronary artery (RCA), the decrease in CBF was found to be more prominent in the LAD compared to the RCA. Removal of the sympathetic innervation to the heart and adrenal demedullation did not alter the decrease in CBF, indicating that the effects of LNAME were not centrally mediated. To determine if the effect of LNAME on CBF was due to a direct action on the coronary vasculature or was secondary to the change in HR, dose-response curves were performed for LNAME (0.3-300 mumol/kg, i.v.) in rats with ventricular pacing. Under these conditions, LNAME still produced an increase in AP and a decrease in CBF, resulting in an increase in coronary vascular resistance. Administration of L-arginine (100-300 mg/kg, i.v.) resulted in a reversal of the cardiovascular effects of LNAME with the reversal being sustained for 1 to 5 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential routes of cocaine administration indicate a peripheral cardiotoxic action

The present study utilized different routes of administration in unanesthetized Wistar Kyoto (WKY) rats to determine whether cocaine-induced death was mediated through a peripheral or central site of action. Administration of cocaine via a route that resulted in high concentrations of cocaine reaching the heart produced arrhythmias, convulsions, a decrease in heart rate and mean arterial pressure, and death. However, administration of the same dose via a route that resulted in passage of cocaine through the liver before reaching the heart produced only a pressor response. Additionally, administration of the same dose via a route that resulted in high levels of cocaine reaching the brain did produce a pressor response that was followed by a decrease in blood pressure and heart rate, arrhythmias, convulsions and death. However, these effects were delayed in comparison to the response when high concentrations of cocaine reached the heart immediately. These results support a peripheral site of action for cocaine-induced death.

Chronic cocaine treatment enhances the responsiveness of the left anterior descending coronary artery and the femoral artery to vasoactive substances

The mechanism by which cocaine produces sudden cardiac death has not been elucidated, but clinical evidence indicates that it may be due to a direct or indirect action on coronary vessels. The present study was designed to compare the responses of the isolated left anterior descending (LAD) coronary artery and femoral artery taken from untreated dogs with the response of these vessels taken from dogs administered cocaine (1 mg/kg i.v.) daily for 4 weeks. The actions of norepinephrine, U-46619 (a thromboxane A2 analog) and serotonin (5-HT) were evaluated. The direct vascular action of cocaine was also determined. Morphology of the blood vessels was evaluated by scanning electron microscopy. Chronic cocaine treatment significantly increased the sensitivity and maximum response of the femoral artery to norepinephrine, U-46619 and 5-HT. The sensitivity of the LAD coronary artery to U-46619 and 5-HT and the maximum response to U-46619 and 5-HT were also enhanced. Vasoconstriction produced by cocaine was not dose dependent and only occurred at high concentrations (10(-5)-10(-4) M). Morphology of the vessels was evaluated by scanning electron microscopy. Femoral arteries from cocaine-treated dogs exhibited loss of endothelial integrity, areas of excessive endothelial cell sloughing and thrombus formation. LAD coronary arteries exhibited only areas of enhanced endothelial cell sloughing. The results of this study indicate that the femoral artery and the LAD coronary artery are more sensitive to endogenous vasoactive substances after chronic cocaine use, which may result in enhanced peripheral vasoconstriction and cardiac ischemia. Morphological results demonstrate femoral arterial thrombosis associated with cocaine use.

Central mechanisms of action involved in cocaine-induced tachycardia

The present study was designed to determine the central effects of cocaine on heart rate and blood pressure in Wistar Kyoto rats (WKY) and to evaluate mechanisms involved in the response. Cocaine (0.025-4 mg/kg) was administered to unanesthetized, unrestrained rats via a cannula placed into the lateral ventricle. Procaine (0.1 and 4 mg/kg) was also administered centrally. Cocaine did not significantly alter blood pressure at doses of 0.025, 0.1, or 0.5 mg/kg, icv. Only the highest dose, 4 mg/kg, icv produced a significant pressor response. Cocaine produced significant dose-dependent tachycardia, with the maximum increase in heart rate occurring within 5 min. Procaine (4 mg/kg, icv) produced tachycardia, but the effect was significantly less than that produced by cocaine (4 mg/kg, icv). Cocaine also produced tachycardia at a dose of 0.1 mg/kg, but procaine did not significantly alter heart rate at the same dose. Central phentolamine pretreatment (0.1 mg/kg, icv) significantly attenuated the increase in heart rate produced by cocaine. These results indicate that the centrally mediated tachycardia produced by cocaine is partly due to its local anesthetic activity and to indirect stimulation of alpha receptors.

Catecholaminergic and opioidergic mechanisms involved in the hypotensive response of pindolol

The present study evaluated the involvement of opioidergic and catecholaminergic mechanisms in the hypotensive action of pindolol. Pindolol (1 mg/kg i.a.) was administered to unanesthetized spontaneously hypertensive rats (SHR) and Wistar Kyoto (WKY) rats instrumented for direct arterial pressure monitoring. Peripheral administration of pindolol produced a significant decrease in blood pressure in both SHR and WKY rats with SHR animals having a greater response. Heart rate was reduced in SHR; however, a tachycardia was observed in WKY rats. Pretreatment with naloxone (100 micrograms/kg i.a.) 10 min prior to pindolol administration prevented the hypotensive response. Similar pretreatment with yohimbine, an alpha 2-receptor antagonist, also prevented the pindolol-induced hypotensive response in both SHR and WKY rats. Neither naloxone nor yohimbine alone significantly affected blood pressure or heart rate. These results suggest that opioidergic and catecholaminergic mechanisms are involved in the hypotensive action of pindolol.

Naloxone pretreatment blocks the hypotensive effects of atenolol in SHR and WKY rats

The present study examined the interaction of opioidergic systems in the hypotensive action of atenolol. Anesthetized, adult spontaneously hypertensive (SHR) and Wistar Kyoto (WKY) rats were instrumented to monitor blood pressure and heart rate. Atenolol (100 micrograms/kg, i.v.) produced a decrease in blood pressure of similar magnitude in both SHR and WKY rats. However, the bradycardia was greater in SHR. Pretreatment with naloxone (0.1 mg/kg, i.v.) 15 min prior to the administration of atenolol completely prevented the hypotensive response in SHR and decreased the maximum hypotensive response by approximately 50% in WKY rats. The atenolol-induced bradycardia was unaffected in both groups of animals. Additionally, pretreatment with yohimbine, an alpha 2-receptor antagonist, inhibited the hypotensive response of atenolol in SHR. Collectively, these results suggest an interaction between opioidergic and catecholaminergic systems as a possible site of action of antihypertensive drugs.

Interaction of propranolol with central serotonergic neurons

Central monoaminergic mechanisms are believed to be involved in cardiovascular regulation. The present study was designed to evaluate the involvement of central serotonergic pathways in the antihypertensive action of propranolol in pentobarbital anesthetized mongrel dogs. Ventriculocisternal perfusion of propranolol (25 ug/kg/min for 30 min) decreased serotonin turnover as indicated by a significant decrease in cerebrospinal fluid levels of 5-hydroxyindoleacetic acid (5-HIAA). This effect was accompanied by a significant reduction in mean arterial pressure and heart rate. These results indicate that propranolol decreases central serotonergic activity and suggests a possible role for central serotonergic pathways in the antihypertensive action of propranolol. Several studies have indicated that central serotonergic pathways participate in the regulation of blood pressure. Brainstem regions including the nucleus tractus solitarius, the raphe nucleus and the anterior hypothalamic preoptic region are involved in cardiovascular control and contain a dense population of serotonergic neurons. A centrally-mediated hypotensive effect of propranolol has been demonstrated. Centrally administered propranolol increases cerebrospinal fluid (CSF) levels of norepinephrine and reduces blood pressure possibly due to decreased peripheral sympathetic nerve activity. Central serotonergic pathways may also be involved in the antihypertensive action of some beta-adrenoceptor antagonists. Destruction of central serotonergic neurons with 5,7-dihydroxytryptamine and desipramine abolished the antihypertensive effect of intracisternal propranolol in sinoaortic denervated dogs. Acute administrations of (-)-propranolol and (-)-pindolol decreased the synthesis rate of serotonin, while acute administration of salbutamol, a beta 2-adrenoceptor agonist, increased 5-HIAA levels in rat brain structures. The present study was designed to evaluate the involvement of central serotonergic pathways in the antihypertensive action of propranolol.

Deafness and biochemical imbalance after burns treatment with topical antibiotics in young children. Report of 6 cases

Six children are described in whom deafness followed treatment of full thickness burns with topical antibiotic spray containing neomycin. 3 children developed hypocalcaemic tetany, and were shown to have a metabolic disorder involving hypocalcaemia, hypomagnesaemia, and hypokalaemia. The dangers of treating burns with topical ototoxic and nephrotoxic antibiotics are emphasised.

Measles inclusion-body encephalitis in a child with treated acute lymphoblastic leukaemia

A child with acute lymphoblastic leukaemia, being treated in the UKALL II Trial, had while in remission an attack of measles and made a normal recovery. Four months later she developed an acute encephalopathy and died within two weeks. The brain showed mild inflammatory features and widespread inclusion bodies in neurones and glial cells. Immunofluorescence proved an infection with measles virus. Similar cases have been called SSPE; reasons are given for preferring the term "measles inclusion-body encephalitis".

Epidemiology of Pseudomonas aeruginosa in a general hospital: a four-year study

A retrospective study was done to determine the epidemiology of infection and/or colonization due to Pseudomonas aeruginosa in a Brazilian general hospital. In 1966, 1968, and 1969, there were only two instances where probable cross-contamination was shown; the remaining isolates were unrelated. In late 1971 the hospital experienced a marked increase in P. aeruginosa isolation. Contaminated dextrose solutions used in the infant feeding were the apparent cause of the problem which occurred in the premature and special care nurseries. A contaminated oxygen humidifying bottle was the source of a different outbreak in surgery. There was also evidence in four instances that cross-infection and/or contamination had occurred. Pyocin and serological typing revealed that many strains were involved and led to a clear understanding of the complex epidemiological relationships among all the strains.

Pyocin typing of Pseudomonas aeruginosa: a simplified method

A simplified method has been devised for typing Pseudomonas aeruginosa by pyocin production. Pyocins are produced as strains grow overnight in Trypticase soy broth (without glucose) plus 1% potassium nitrate. Because P. aeruginosa can use nitrate instead of oxygen as a terminal electron acceptor, mechanical shaking is not necessary, nor is induction by mitomycin C. Pyocins can now be produced in screw-cap tubes in a water bath or incubator. A total of 250 strains were tested as possible pyocin indicators, which included 60 strains already used in pyocin-typing systems. The final set contained 18 indicators which were chosen because (i) they had clear positive or clear negative reactions, thus eliminating reactions difficult to read, (ii) they had few zones due to bacteriophage lysis, and (iii) they were most sensitive in differentiating clinical isolates of P. aeruginosa. The final typing method was tested in several studies and the results were clear; thus definitive epidemiological conclusions could be made. Because it is simple to perform and easily automated, the new method should have application in many hospitals; however, it should be used only in carefully planned epidemiological studies. The method and its application are described in detail, and some pitfalls are discussed.

Pyocin sensitivity of Pseudomonas species

Only the fluorescent pseudomonads, Pseudomonas aeruginosa, P. putida, and P. fluorescens, were sensitive to pyocins produced from P. aeruginosa.

Simplified method for producing pyocins from Pseudomonas aeruginosa

Good yields of pyocin are obtained when Pseudomonas aeruginosa is grown in Trypticase soy broth (without glucose) (BBL) plus 1% potassium nitrate. As a result, pyocin production for routine epidemiological typing can be done in screw-cap tubes, without mechanical agitation or mitomycin C induction.

Nursery outbreak of Pseudomonas aeruginosa: epidemiological conclusions from five different typing methods

In April 1971, nine cases of Pseudomonas aeruginosa septicemia occurred in a high-risk nursery. The epidemiology of the outbreak was studied by pyocin production, pyocin sensitivity, serological typing, antibiotic susceptibility, and phenotypic properties such as colonial morphology, pigment, and hemolysis. Ten isolates of P. aeruginosa were recovered from 9 newborn infants and from 13 environmental sources. Twenty-one of the 23 isolates had identical pyocin production patterns against 60 different indicator strains and were of the same serotype. These 21 isolates were designated as the "outbreak strain"; the other 2 isolates had no epidemiological significance. The results of pyocin sensitivity, antibiotic susceptibility tests, and phenotypic properties were dissimilar. They would yield incorrect epidemiological conclusions if used alone. The outbreak strain dissociated in vitro and these phenotypic changes accounted for the variable results by the latter three typing methods. Although the precise mode of introduction of the organism into the nursery could not be determined in retrospect, the epidemiological data strongly suggested that one infant contracted a P. aeruginosa infection, and this strain spread throughout the nursery by means of contaminated resuscitation equipment.