COVID-19 vaccine reactogenicity among participants enrolled in the GENCOV study

BACKGROUND

GENCOV is a prospective, observational cohort study of COVID-19-positive adults. Here, we characterize and compare side effects between COVID-19 vaccines and determine whether reactogenicity is exacerbated by prior SARS-CoV-2 infection.

METHODS

Participants were recruited across Ontario, Canada. Participant-reported demographic and COVID-19 vaccination data were collected using a questionnaire. Multivariable logistic regression was performed to assess whether vaccine manufacturer, type, and previous SARS-CoV-2 infection are associated with reactogenicity.

RESULTS

Responses were obtained from n = 554 participants. Tiredness and localized side effects were the most common reactions across vaccine doses. For most participants, side effects occurred and subsided within 1-2 days. Recipients of Moderna mRNA and AstraZeneca vector vaccines reported reactions more frequently compared to recipients of a Pfizer-BioNTech mRNA vaccine. Previous SARS-CoV-2 infection was independently associated with developing side effects.

CONCLUSIONS

We provide evidence of relatively mild and short-lived reactions reported by participants who have received approved COVID-19 vaccines.

Characterizing Risk Factors for Hospitalization and Clinical Characteristics in a Cohort of COVID-19 Patients Enrolled in the GENCOV Study

The GENCOV study aims to identify patient factors which affect COVID-19 severity and outcomes. Here, we aimed to evaluate patient characteristics, acute symptoms and their persistence, and associations with hospitalization. Participants were recruited at hospital sites across the Greater Toronto Area in Ontario, Canada. Patient-reported demographics, medical history, and COVID-19 symptoms and complications were collected through an intake survey. Regression analyses were performed to identify associations with outcomes including hospitalization and COVID-19 symptoms. In total, 966 responses were obtained from 1106 eligible participants (87% response rate) between November 2020 and May 2022. Increasing continuous age (aOR: 1.05 [95%CI: 1.01-1.08]) and BMI (aOR: 1.17 [95%CI: 1.10-1.24]), non-White/European ethnicity (aOR: 2.72 [95%CI: 1.22-6.05]), hypertension (aOR: 2.78 [95%CI: 1.22-6.34]), and infection by viral variants (aOR: 5.43 [95%CI: 1.45-20.34]) were identified as risk factors for hospitalization. Several symptoms including shortness of breath and fever were found to be more common among inpatients and tended to persist for longer durations following acute illness. Sex, age, ethnicity, BMI, vaccination status, viral strain, and underlying health conditions were associated with developing and having persistent symptoms. By improving our understanding of risk factors for severe COVID-19, our findings may guide COVID-19 patient management strategies by enabling more efficient clinical decision making.

Public knowledge of SARS-CoV-2 serological and viral lineage laboratory testing and result interpretation: A GENCOV study cross-sectional survey

OBJECTIVES

Concepts related to SARS-CoV-2 laboratory testing and result interpretation can be challenging to understand. A cross-sectional survey of COVID-19 positive adults residing in Ontario, Canada was conducted to explore how well people understand SARS-CoV-2 laboratory tests and their associated results.

DESIGN AND METHODS

Participants were recruited through fliers or by prospective recruitment of outpatients and hospitalized inpatients with COVID-19. Enrolled participants included consenting adults with a positive SARS-CoV-2 polymerase chain reaction test result. An 11-item questionnaire was developed by researchers, nurses, and physicians in the study team and was administered online between April 2021 to May 2022 upon enrolment into the study.

RESULTS

Responses were obtained from 940 of 1106 eligible participants (85% participation rate). Most respondents understood 1) that antibody results should not influence adherence to social distancing measures (n=602/888, 68%), 2) asymptomatic SARS-CoV-2 infection following test positivity (n=698/888, 79%), 3) serological test sensitivity in relation to post-infection timeline (n=540/891, 61%), and 4) limitations of experts' knowledge related to SARS-CoV-2 serology (n=693/887, 78%). Conversely, respondents demonstrated challenges understanding 1) conflicting molecular and serological test results and their relationship with immune protection (n=162/893, 18%) and 2) the impact of SARS-CoV-2 variants on vaccine effectiveness (n=235/891, 26%). Analysis of responses stratified by sociodemographic variables identified that respondents who were either: 1) female, 2) more educated, 3) aged 18-44, 4) from a high-income household, or 5) healthcare workers responded expectedly more often.

CONCLUSIONS

We have highlighted concepts related to SARS-CoV-2 laboratory tests and associated results which may be challenging to understand. The findings of this study enable us to identify 1) misconceptions related to various SARS-CoV-2 test results, 2) groups of individuals at risk, and 3) strategies to improve people's understanding of their test results.

Genome Reporting for Healthy Populations-Pipeline for Genomic Screening from the GENCOV COVID-19 Study

Genome sequencing holds the promise for great public health benefits. It is currently being used in the context of rare disease diagnosis and novel gene identification, but also has the potential to identify genetic disease risk factors in healthy individuals. Genome sequencing technologies are currently being used to identify genetic factors that may influence variability in symptom severity and immune response among patients infected by SARS-CoV-2. The GENCOV study aims to look at the relationship between genetic, serological, and biochemical factors and variability of SARS-CoV-2 symptom severity, and to evaluate the utility of returning genome screening results to study participants. Study participants select which results they wish to receive with a decision aid. Medically actionable information for diagnosis, disease risk estimation, disease prevention, and patient management are provided in a comprehensive genome report. Using a combination of bioinformatics software and custom tools, this article describes a pipeline for the analysis and reporting of genetic results to individuals with COVID-19, including HLA genotyping, large-scale continental ancestry estimation, and pharmacogenomic analysis to determine metabolizer status and drug response. In addition, this pipeline includes reporting of medically actionable conditions from comprehensive gene panels for Cardiology, Neurology, Metabolism, Hereditary Cancer, and Hereditary Kidney, and carrier screening for reproductive planning. Incorporated into the genome report are polygenic risk scores for six diseases-coronary artery disease; atrial fibrillation; type-2 diabetes; and breast, prostate, and colon cancer-as well as blood group genotyping analysis for ABO and Rh blood types and genotyping for other antigens of clinical relevance. The genome report summarizes the findings of these analyses in a way that extensively communicates clinically relevant results to patients and their physicians. © 2022 Wiley Periodicals LLC. Basic Protocol 1: HLA genotyping and disease association Basic Protocol 2: Large-scale continental ancestry estimation Basic Protocol 3: Dosage recommendations for pharmacogenomic gene variants associated with drug response Support Protocol: System setup.

Effect of low dose intracoronary alteplase on global circumferential strain (myocardial strain CMR substudy from the T-TIME trial)

Background

Microvascular obstruction affects half of patients with ST-segment elevation myocardial infarction (STEMI) and confers an adverse prognosis. Feature-tracking (FT) cardiac magnetic resonance (CMR) allows myocardial strain assessment from standard cine images without the need for specialist sequences. Myocardial strain reflects both systolic and diastolic function allowing the assessment of both global and regional myocardial deformation. Strain recovery is impaired in patients with microvascular obstruction. There is growing evidence to suggest that global circumferential strain may offer incremental value beyond traditional CMR endpoints.

Purpose

We aimed to determine whether a therapeutic strategy involving low-dose intracoronary alteplase improves global circumferential strain in STEMI.

Methods

Between March 17, 2016, and December 21, 2017, 440 patients presenting at 11 hospitals in the United Kingdom within 6 hours of STEMI were randomised in a 1:1:1 dose-ranging trial design. Participants were randomly assigned to treatment with placebo (n=151), alteplase 10mg (n=144), or alteplase 20mg (n=145). The primary outcome was the amount of microvascular obstruction (%left ventricular mass) quantified by CMR at 2–7 days. Global circumferential strain was a prespecified secondary endpoint measured at 2–7 days and 3 months. Troponin T AUC was measured at 0, 2, and 24 hours post reperfusion. Patients were followed up to 1 year with all events adjudicated by an independent committee.

Results

Among the 440 patients who were randomised (mean age 60.5 years; 85% male), the primary endpoint was achieved in 396 (90%), all patients were followed up to 1 year for clinical events. The amount (mean, standard deviation) of microvascular obstruction was not different between the groups (2.3% vs. 2.6% vs. 3.5% left ventricular mass); p=0.28. Global circumferential strain was worse in patients receiving alteplase. −23.1% (placebo) vs −20.6 (10mg alteplase) vs −22.0% (20mg alteplase); mean difference for both doses combined vs placebo: 1.8% (95% CI 0.5, 3.2), p=0.009. There were no differences between groups in the other CMR endpoints including LV ejection fraction (LVEF). The area-under-the-curve for troponin T measured in 317 (72%) patients was increased in both treatment groups compared to placebo, mean difference 1.53 (95% CI: 1.16, 2.01), p=0.002. There were no differences in MACE at 1 year; placebo n=16 (10.6%), 10mg alteplase n=22 (15.3%), 20mg alteplase group n=15 (10.3%).

Conclusion

In patients presenting within 6 hours of STEMI, low-dose intracoronary alteplase compared with placebo did not reduce microvascular obstruction. There was a reduction in global circumferential strain and an increase in Troponin T AUC supporting an increase in myocardial injury early after reperfusion in patients receiving alteplase. There was no differences in MACE at one year suggesting no long-term clinical sequelae.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): T-TIME was supported by grant 12/170/4 from the Efficacy and Mechanism Evaluation (EME) programme of the National Institute for Health Research (NIHR-EME). Boehringer-Ingelheim U.K. Ltd. provided the study drugs (alteplase 10mg, 20mg), matched placebo, and sterile water for injection. Study recruitment flowchartTable- Study endpoints

Implementation of serological and molecular tools to inform COVID-19 patient management: protocol for the GENCOV prospective cohort study

INTRODUCTION

There is considerable variability in symptoms and severity of COVID-19 among patients infected by the SARS-CoV-2 virus. Linking host and virus genome sequence information to antibody response and biological information may identify patient or viral characteristics associated with poor and favourable outcomes. This study aims to (1) identify characteristics of the antibody response that result in maintained immune response and better outcomes, (2) determine the impact of genetic differences on infection severity and immune response, (3) determine the impact of viral lineage on antibody response and patient outcomes and (4) evaluate patient-reported outcomes of receiving host genome, antibody and viral lineage results.

METHODS AND ANALYSIS

A prospective, observational cohort study is being conducted among adult patients with COVID-19 in the Greater Toronto Area. Blood samples are collected at baseline (during infection) and 1, 6 and 12 months after diagnosis. Serial antibody titres, isotype, antigen target and viral neutralisation will be assessed. Clinical data will be collected from chart reviews and patient surveys. Host genomes and T-cell and B-cell receptors will be sequenced. Viral genomes will be sequenced to identify viral lineage. Regression models will be used to test associations between antibody response, physiological response, genetic markers and patient outcomes. Pathogenic genomic variants related to disease severity, or negative outcomes will be identified and genome wide association will be conducted. Immune repertoire diversity during infection will be correlated with severity of COVID-19 symptoms and human leucocyte antigen-type associated with SARS-CoV-2 infection. Participants can learn their genome sequencing, antibody and viral sequencing results; patient-reported outcomes of receiving this information will be assessed through surveys and qualitative interviews.

ETHICS AND DISSEMINATION

This study was approved by Clinical Trials Ontario Streamlined Ethics Review System (CTO Project ID: 3302) and the research ethics boards at participating hospitals. Study findings will be disseminated through peer-reviewed publications, conference presentations and end-users.

Quantification of biomaterial dispersion during otologic procedures and role of barrier drapes in Covid 2019 era - a laboratory model

BACKGROUND

Aerosol generation during temporal bone surgery caries the risk of viral transmission. Steps to mitigate this problem are of particular importance during the coronavirus disease 2019 pandemic.

OBJECTIVE

To quantify the effect of barrier draping on particulate material dispersion during temporal bone surgery.

METHODS

The study involved a cadaveric model in a simulated operating theatre environment. Particle density and particle count for particles sized 1-10 μ were measured in a simulated operating theatre environment while drilling on a cadaveric temporal bone. The effect of barrier draping to decrease dispersion was recorded and analysed.

RESULTS

Barrier draping decreased counts of particles smaller than 5 μ by a factor of 80 in the operating theatre environment. Both particle density and particle count showed a statistically significant reduction with barrier draping (p = 0.027).

CONCLUSION

Simple barrier drapes were effective in decreasing particle density and particle count in the operating theatre model and can prevent infection in operating theatre personnel.

Permanent pacemaker insertion after CoreValve transcatheter aortic valve implantation: incidence and contributing factors (the UK CoreValve Collaborative)

BACKGROUND

Permanent pacemaker (PPM) requirement is a recognized complication of transcatheter aortic valve implantation. We assessed the UK incidence of permanent pacing within 30 days of CoreValve implantation and formulated an anatomic and electrophysiological model.

METHODS AND RESULTS

Data from 270 patients at 10 centers in the United Kingdom were examined. Twenty-five patients (8%) had preexisting PPMs; 2 patients had incomplete data. The remaining 243 were 81.3±6.7 years of age; 50.6% were male. QRS duration increased from 105±23 to 135±29 milliseconds (P<0.01). Left bundle-branch block incidence was 13% at baseline and 61% after the procedure (P<0.001). Eighty-one patients (33.3%) required a PPM within 30 days. Rates of pacing according to preexisting ECG abnormalities were as follows: right bundle-branch block, 65.2%; left bundle-branch block, 43.75%; normal QRS, 27.6%. Among patients who required PPM implantation, the median time to insertion was 4.0 days (interquartile range, 2.0 to 7.75 days). Multivariable analysis revealed that periprocedural atrioventricular block (odds ratio, 6.29; 95% confidence interval, 3.55 to 11.15), balloon predilatation (odds ratio, 2.68; 95% confidence interval, 2.00 to 3.47), use of the larger (29 mm) CoreValve prosthesis (odds ratio, 2.50; 95% confidence interval, 1.22 to 5.11), interventricular septum diameter (odds ratio, 1.18; 95% confidence interval, 1.10 to 3.06), and prolonged QRS duration (odds ratio, 3.45; 95% confidence interval, 1.61 to 7.40) were independently associated with the need for PPM.

CONCLUSION

One third of patients undergoing a CoreValve transcatheter aortic valve implantation procedure require a PPM within 30 days. Periprocedural atrioventricular block, balloon predilatation, use of the larger CoreValve prosthesis, increased interventricular septum diameter and prolonged QRS duration were associated with the need for PPM.

Radiation therapy with implanted cardiac pacemaker devices: a clinical and dosimetric analysis of patients and proposed precautions

AIMS

To report the radiation planning dosimetric aspects and clinical outcomes of patients with implanted cardiac pacemakers.

MATERIALS AND METHODS

Between 2005 and 2009, eight patients with in situ cardiac pacemakers of varied primary site were treated at our hospital. All patients underwent computed tomography-based treatment planning. The target volumes, organs at risk and pacemaker device were all contoured. A treatment plan optimally covering the target area and maximally sparing the pacemaker was generated. All patients were evaluated at baseline, during radiotherapy and after radiotherapy conclusion by a cardiologist as well as pacemaker company personnel.

RESULTS

The median age at presentation was 67 (range 53-77) years. There were three men with head and neck primaries, two men with lung primaries and three women with breast primaries. The prescribed dose ranged from 45 to 70 Gy in 25-35 fractions with a daily dose of 1.8-2.0 Gy. Four patients had the pacemaker implanted on the same side as the radiotherapy target. The dose ranges for the minimum, mean and maximum doses to the pacemaker were 0.06-2.0, 0.07-20.6 and 0.14-60.0 Gy, respectively. Radiation therapy was safely delivered in all patients without any untoward effects. At 5 months of median follow-up, all patients were well with no malfunction of the pacemaker.

CONCLUSION

A series of eight patients with in situ pacemakers treated with radiotherapy is reported. Radiotherapy can be safely delivered in patients with implanted cardiac pacemakers. However, it mandates a cautious approach in planning and treatment delivery to ensure the least possible dose to the pacemaker. Close liaison with the cardiologist and a pacemaker clinic before, during and after the course of treatment is essential to ensure patient safety.

The infiltrative, diffuse pattern of recurrence in patients with malignant gliomas treated with bevacizumab

2057

Background: There is no standard of care for recurrent gliomas; however, bevacizumab is often used as a salvage chemotherapy regimen. A diffuse, infiltrative pattern of recurrence, as evidenced by MR imaging, was seen manifesting as multifocal disease or presumed CSF dissemination with subependymal spread. Methods: We conducted a retrospective analysis of 40 recurrent glioma patients followed at Moffitt Cancer Center from September 2006 through December 2008 treated with bevacizumab alone or in combination with irinotecan. Histologies included glioblastoma (GB), anaplastic astrocytomas (AA), anaplastic oligodendrogliomas (AO), anaplastic oligoastrocytomas (AOA), and low-grade astrocytomas. Rate of diffuse, infiltrative recurrence, progression free survival (PFS) and overall survival (OS) were analyzed and correlated with respect to specific prognostic variables. Results: 38% (15) of the patients were female and 63% (25) were male. The median (range) age was 51 (20–72) years. The median (range) KPS was 80 (50–100). Twenty-six (65%) patients had GB, 8 (20%) AA, 2 (5%) AO, and 3 (8%) AOA and 1 (3%) had LGA. Five (13%) patients had a gross total resection (GTR), 23 (58%) a subtotal resection (STR) and 12 (30%) had biopsy only. The median (range) number of prior therapies was 2 (1–7). At time of analysis 28 (70%) patients had died. Incidence of diffuse, infiltrative recurrence was seen in 8 (20%) of patients (95% CI: [9%, 36%]). This recurrence seems to be negatively associated with age: rate for age<=50: 6/18 (33%); (95% CI: [13%, 59%]) while rate for age>50: 2/22 (9%); (95% CI: [1%, 29%]), with an odds ratio (OR) of 5.0. Conclusions: There appears to be an increase in a diffuse, infiltrative pattern of recurrence among recurrent glioma patients treated with bevacizumab as a salvage regimen. In our experience, this appears most prevalent in patients less than 50 years of age. It is unclear why the disparity among this subset of patients occurs, however, we hypothesize that this may once again highlight the distinct tumor biology among young glioma patients. The impact of this observation on clinical decision making on whether to utilize bevacizumab in young recurrent glioma patients warrants further investigation.

[Table: see text]

Feasibility and phase I trial of tandutinib in patients with recurrent glioblastoma

2039

Background: Platelet-derived growth factor signaling is important in gliomagenesis and PDGFR-β is expressed on >90% of endothelial cells in glioblastoma specimens. Methods: We report the results of a feasibility and phase I study of tandutinib (MLN518), an orally bioavailable, quinazoline-based inhibitor of type III receptor tyrosine kinases including PDGFR-β, FLT-3, and c-Kit, in patients with recurrent glioblastoma (GBM) conducted in the New Approaches to Brain Tumor Therapy (NABTT) consortium. Results: A feasibility study was conducted in 6 recurrent GBM patients in whom resection was clinically indicated. These patients received tandutinib 500-mg BID for 7 days prior to resection. In these patients, the drug was measured in tumor tissue and plasma samples obtained shortly before and after the resection by LC/MS. The mean ± SD concentration of tandutinib in tumor tissue was 7.2 ± 3.2 μg/mL and the mean ratio of its concentration in brain tumor-to-plasma was 9.6 ± 7.7. A phase I study was conducted in 19 patients to determine the MTD in this recurrent GBM population with sequential assessment of the following dose levels: 500-, 600-, and 700-mg BID. Four patients were replaced due to early withdrawal unrelated to toxicity. Dose limiting toxicities were observed in 1/6 patients at 500-mg BID (grade 3 phosphorous, grade 3 fatigue, grade 3 somnolence in 1 patient); 1/6 patients at 600-mg BID (grade 3 phosphorous); 2/3 patients at 700-mg BID (grade 3 fatigue, grade 3 weakness). 600-mg BID was declared the MTD and a phase II study has been initiated at this dose level. Conclusions: The mean brain tumor tissue-to-plasma ratio of tandutinib in GBM patients receiving 500-mg BID exceeded the estimated threshold ratio of 0.33 that was considered as being necessary to achieve local cytotoxic concentrations in brain tumors. The MTD of tandutinib in the recurrent GBM population is 600-mg BID. A phase II trial has been initiated at this dose level.

[Table: see text]

The influence of small fibre muscle mechanoreceptors on the cardiac vagus in humans

We have previously shown that activation of muscle receptors by passive stretch (PS) increases heart rate (HR) with little change in blood pressure (BP). We proposed that PS selectively inhibits cardiac vagal activity. We attempted to test this by performing PS during experimental alterations in vagal tone. Large decreases in vagal tone were induced using either glycopyrrolate or mild rhythmic exercise. Milder alterations in vagal tone were achieved by altering carotid baroreceptor input: neck pressure (NP) or neck suction (NS). PS of the triceps surae was tested in 14 healthy human volunteers. BP, ECG and respiration were recorded. PS alone caused a significant decrease (P < 0.05) in R-R interval (962 +/- 76 ms at baseline compared to 846 +/- 151 ms with PS), and showed a reduction in HR variability, which was not significant. The decrease in R-R interval with PS was significantly less (P < 0.05, n = 3) following administration of glycopyrrolate (-8.1 +/- 4.5 ms) compared to PS alone (-54 +/- 11 ms), and also with PS during handgrip (+10 +/- 10 ms) compared with PS alone (-74 +/- 15 ms) (P < 0.05, n = 5). Milder reductions in vagal activity (NP) resulted in a small but insignificant further decrease in R-R interval in response to PS (-107 +/- 17 ms compared to PS alone -96 +/- 13 ms, n = 5). Mild increases in vagal activity (NS) during PS resulted in smaller decreases in R-R interval (-39 +/- 5.5 ms) compared to PS alone (-86 +/- 17 ms) (P < 0.05, n = 8). BP was not significantly changed by stretch in any tests. The results indicate that amongst muscle receptors there is a specific group activated by stretch that selectively inhibit cardiac vagal tone to produce tachycardia.

Cutaneous tuberculosis in Indian children: the importance of screening for involvement of internal organs

AIMS AND OBJECTIVES

Resurgence of skin tuberculosis especially with drug-resistant strains has been well documented in recent years, but this problem has not received much attention in the paediatric age group. Hence, we carried out the present study to analyse the clinical and therapeutic aspects of cutaneous tuberculosis in children.

MATERIALS AND METHODS

A detailed clinical examination, investigations, such as haemogram, serology for HIV, Mantoux test, chest X-ray, cytology, culture and histopathology were carried out in all children. They were treated with antitubercular therapy (WHO regimen), and the clinical response was followed up.

RESULTS

Of 142 patients with cutaneous tuberculosis, 68 were children (40 females, 28 males). These children were aged from 9 months to 14 years. The duration of the disease varied from 1 month to 6 years. Family history of tuberculosis was present in 28 (41.2%) of the patients. Scrofuloderma was the most common presentation encountered in 30 (44.1%) patients with preferential involvement of the cervical (56.2%) and inguinal (20%) regions. Fifteen (22.1%) patients had lupus vulgaris, of which the keratotic type was the most common (46.7%), 16 had lichen scrofulosorum, three had tuberculosis verrucosa cutis, and four had more than one type of tuberculosis. Involvement of the lung in 14 (20.6%), bone in seven (10.2%), and both in four (5.9%) was found. Histopathology corroborated the clinical diagnosis in 54 (80.6%), culture was positive in six (8.8%). Fifty (73.5%) patients completed the treatment with an excellent response, no multidrug resistant cases were seen.

CONCLUSIONS

Cutaneous tuberculosis in children continues to be an important cause of morbidity, there is a high likelihood of internal involvement, especially in patients with scrofuloderma. A search is required for more sensitive, economic diagnostic tools. Response to treatment at 4 weeks often helps in substantiating the diagnosis of tuberculosis in doubtful cases.

Cysts of the ejaculatory system--a treatable cause of recurrent epididymo-orchitis in children

The commonest causes of acutely painful scrotum are torsion (of appendix of the testis or the testis itself) and epididymo-orchitis. Exploration is the only way to prove the diagnosis and multiple such procedures are performed in patients with recurrent epididymo-orchitis. The purpose of our study was to investigate the cause of recurrent epididymo-orchitis in pre-pubertal children. Four children, aged three years or less, were investigated for recurrent left epididymo-orchitis. All four had cystic dilatation of the ejaculatory duct in the region of the prostatic utriculus, associated in two children with ectopic opening of the vas in the bladder. Initial ultrasound appeared to be normal in all four patients, a retrospective review of the sonographic films, however, revealed a retrovesical cyst in three of them. The diagnosis was established by a combination of urethroscopy with retrograde contrast study via the utriculus and open vasography. All four cases were treated operatively by a transtrigonal approach. The cyst was excised in each case. In one, a vasovasostomy was performed between the left and the normal right vas; in the other three the left vas was anastomosed to the blind end of the contralateral seminal vesicle. All four are symptom-free at one year follow-up. Cysts of the ejaculatory duct are a treatable cause of recurrent epididymo-orchitis. Pre-pubertal children with recurrent epididymo-orchitis and no obvious underlying cause should have a thorough sonographic examination of the retrovesical region for cystic lesions.

Chronotropic effects of nitric oxide in the denervated human heart

Nitric oxide synthase is expressed in the sino-atrial node and animal data suggests a direct role for nitric oxide on pacemaker activity. Study of this mechanism in intact humans is complicated by both reflex and direct effects of nitric oxide on cardiac autonomic control. Thus, we have studied the direct effects of nitric oxide on heart rate in human cardiac transplant recipients who possess a denervated donor heart. In nine patients, the chronotropic effects of systemic injection of the nitric oxide synthase inhibitor N(G)-monomethyl-L-arginine (L-NMMA) (3 mg kg(-1)) or increasing bolus doses of the nitric oxide donor, sodium nitroprusside (SNP), were studied. Injection of L-NMMA increased mean arterial pressure by 17 +/- 2 mmHg (mean +/- S.E.M.; P < 0.001) and also had a significant negative chronotropic effect, lengthening the R-R interval by 54 +/- 8 ms (P < 0.001). This bradycardia was not reflex in origin since injection of the non-NO-dependent vasoconstrictor, phenylephrine (100 microg) achieved a similar rise in mean arterial pressure (18 +/- 3 mmHg; P < 0.001) but failed to change R-R interval duration (Delta R-R = -3 +/- 4 ms). Furthermore, no change in levels of circulating adrenaline was observed with L-NMMA. Conversely, injection of sodium nitroprusside resulted in a positive chronotropic effect with a dose-dependent shortening of R-R interval duration, peak Delta R-R = -25 +/- 8 ms with 130 microg (P < 0.01). These findings indicate that nitric oxide exerts a tonic, direct, positive chronotropic influence on the denervated human heart. This is consistent with the results of animal experiments showing that nitric oxide exerts a facilitatory influence on pacemaking currents in the sino-atrial node.

Heart rate variability--a therapeutic target?

Reduced heart rate variability (HRV) is a powerful and independent predictor of an adverse prognosis in patients with heart disease and in the general population. The HRV is largely determined by vagally mediated beat to beat variability, conventionally known as respiratory sinus arrhythmia. Thus, HRV is primarily an indicator of cardiac vagal control. It is still unclear whether the relationship between measures of cardiac vagal control and mortality is causative or mere association. Possible mechanisms by which cardiac vagal activity might beneficially influence prognosis include a decrease in myocardial oxygen demand, a reduction in sympathetic activity and a decreased susceptibility of the ventricular myocardium to lethal arrhythmia. In animals, augmentation of cardiac vagal control by nerve stimulation or by drugs is associated with a reduction in sudden death in susceptible models. In humans a number of drugs which have been shown to reduce mortality and sudden death in large randomised trials can also be demonstrated to increase HRV. As a result of this evidence, it has been suggested that the effect of drugs or other therapeutic manoeuvres on HRV might be used to predict clinical efficacy. The use of HRV as a therapeutic target is discussed in this review.

Effects of angiotensin II (AT1) receptor blockade on cardiac vagal control in heart failure

The objective of the present study was to determine the autonomic effects of angiotensin II (AT(1)) receptor blocker therapy in heart failure. In a randomized double-blind cross-over study, we compared the effects of candesartan and placebo on baroreflex sensitivity and on heart rate variability at rest, during stress and during 24 h monitoring. Acute effects were assessed 4 h after oral candesartan (8 mg) and chronic effects after 4 weeks of treatment (dose titrated to 16 mg daily). The study group comprised 21 patients with heart failure [mean (S.E.M.) ejection fraction 33% (1%)], in the absence of angiotensin-converting enzyme (ACE) inhibitor therapy. We found that acute candesartan was not different from placebo in its effects on blood pressure or mean RR interval. Chronic candesartan significantly reduced blood pressure [placebo, 137 (3)/82 (3) mmHg; candesartan, 121 (4)/75 (2) mmHg; P<0.001; values are mean (S.E.M.)], but had no effect on mean RR interval [placebo, 857 (25) ms; candesartan, 857 (21) ms]. Compared with placebo there were no significant effects of acute or chronic candesartan on heart rate variability in the time domain and no consistent effects in the frequency domain. Baroreflex sensitivity assessed by the phenylephrine bolus method was significantly increased after chronic candesartan [placebo, 3.5 (0.5) ms/mmHg; candesartan, 4.8 (0.7) ms/mmHg; P<0.05], although there were no changes in cross-spectral baroreflex sensitivity. Thus, in contrast with previous results with ACE inhibitors, angiotensin II receptor blockade in heart failure did not increase heart rate variability, and there was no consistent effect on baroreflex sensitivity.

Application of the Malone antegrade continence enema principle in degenerative leiomyopathy

An 1-year-old boy with degenerative leiomyopathy (DL) presented with a volvulus of the transverse colon. After derotating the volvulus, we constructed a tube colostomy (TC) from the transverse colon. This TC has been used for the past 2 years by the patient for regular deflation of the colon and antegrade colonic enemas (ACE). We present this as a preliminary report of the use of the Malone ACE procedure in a patient with DL and review the relevant literature.

Nitric oxide and hypertension: not just an endothelium derived relaxing factor!

The importance of endothelial nitric oxide (NO) generation in sustaining a tonic systemic vasodilatation is well established. Inhibiting NO production produces hypertension in animals and in humans and not surprisingly there has been considerable interest in establishing whether deficiencies of endothelial NO pathway activity are implicated in the aetiology of essential hypertension. The results of these investigations have been inconsistent with some suggestion that observed deficiencies of both basal and stimulated endothelial NO generation in hypertensive subjects may be an effect rather than the cause of raised arterial pressure. It is increasingly recognised that neuronal production of NO also influences cardiovascular homeostasis through its action as a neuromodulator within the autonomic nervous system. Overall NO has been shown to have sympatho-inhibitory and vagotonic effects, acting by both central and peripheral mechanisms. Sympathetic overactivity, coupled with the permissive role of a depressed level of baroreflex mediated cardiac vagal control, may play a significant role in the genesis of human hypertension. Early work in hypertensive rats suggests that neuronal NO production is impaired at a number of key central sites concerned with autonomic cardiovascular regulation. This data is consistent with the pattern of autonomic dysfunction observed in human hypertension. The possibility that neuronal rather than endothelial production of NO might play a significant role in the aetiology of essential hypertension is a promising area for future human research.

Renal pathological findings in infective endocarditis

BACKGROUND

Accounts of renal pathological findings in infective endocarditis are mostly based on studies from many years ago. We reviewed a group of patients with infective endocarditis in the light of modern concepts of renal pathology, including the largest reported series of renal biopsies in this condition.

METHODS

Renal tissue was available for retrospective study from 62 patients with confirmed infective endocarditis out of 354 diagnosed with the disease between 1981 and 1998 inclusive. Twenty patients had a renal biopsy and 42 a necropsy.

RESULTS

Common renal lesions noted were localized infarcts in 31%, noted only in necropsy material, and acute glomerulonephritis in 26%, noted in biopsy and necropsy material. The commonest type of glomerulonephritis was vasculitic, without deposition of immunoproteins in glomeruli. Of the renal infarcts over half were due to septic emboli, mostly in patients infected with Staphylococcus aureus. Acute interstitial nephritis was found in 10% but was more common in biopsy material and seemed attributable to antibiotics. Renal cortical necrosis found in 10% was apparent only at necropsy. There were various other findings in the kidney.

CONCLUSIONS

The kidneys are commonly affected in infective endocarditis by a variety of complications of clinical significance. The commonest type of glomerulonephritis does not appear to be attributable to deposition of immune complexes. A renal biopsy may be helpful in the investigation of renal impairment in a patient with infective endocarditis.

Nitric oxide and cardiac autonomic control in humans

Cardiac autonomic control is of prognostic significance in cardiac disease, yet the control mechanisms of this system remain poorly defined. Animal data suggest that nitric oxide (NO) modulates cardiac autonomic control. We investigated the influence of NO on the baroreflex control of heart rate in healthy human subjects. In 26 healthy male volunteers (mean age, 23+/-5 years), we measured heart rate variability and baroreflex sensitivity during inhibition of endogenous NO production with N(G)-monomethyl-L-arginine (L-NMMA) (3 mg/kg per hour) and during exogenous NO donation with sodium nitroprusside (1 to 3 mg/h). Increases from baseline (Delta) in high-frequency (HF) indexes of heart rate variability were smaller with L-NMMA in comparison to an equipressor dose of the control vasoconstrictor phenylephrine (12 to 42 microg/kg per hour): Deltaroot mean square of successive RR interval differences (DeltaRMSSD)=23+/-32 versus 51+/-48 ms (P<0.002); Deltapercentage of successive RR interval differences >50 ms (DeltapNN50)=5+/-15% versus 14+/-12% (P<0.05); and DeltaHF normalized power=-2+/-7 versus 9+/-8 normalized units (P<0.01), respectively. Relative preservation of these indexes was observed during unloading of the baroreflex with sodium nitroprusside compared with a matched fall in blood pressure produced by a control vasodilator, hydralazine (9 to 18 mg/h): DeltaRMSSD=-8+/-8 versus -24+/-15 ms (P<0.001); DeltapNN50=-6+/-11% versus -15+/-19% (P<0.01); DeltaHF normalized power=-7+/-13 versus -13+/-11 normalized units (P<0.05), respectively. The change in cross-spectral alpha-index calculated as the square root of the ratio of RR interval power to systolic spectral power in the HF band (although not alpha-index calculated in the same way for the low-frequency bands or baroreflex sensitivity assessed by the phenylephrine bolus method) was attenuated with L-NMMA compared with phenylephrine (Delta=4+/-8 versus 14+/-15 ms/mm Hg, respectively; P<0.02) and with sodium nitroprusside compared with hydralazine (Delta=-7+/-6 and -9+/-7 ms/mm Hg, respectively; P<0.05). In conclusion, these data demonstrate that NO augments cardiac vagal control in humans.

Role of nitric oxide in the regulation of cardiovascular autonomic control

Alteration in function of the cardiac autonomic nervous system has proved to be a powerful predictor of cardiac death or serious arrhythmia in patients with cardiac disease, yet little is known about the mechanisms by which this system is regulated. Recent evidence suggests that the gaseous molecule nitric oxide (NO) may act as an important mediator in this pathway. Histochemical staining techniques have identified neuronal populations that contain NO synthase within medullary cardio-regulatory sites and their peripheral autonomic pathways. Drugs that modulate the NO pathway (administered both systemically and into the central nervous system) cause changes in pre- and post-ganglionic sympathetic nerve activity that imply that NO serves to inhibit central sympathetic outflow. There is also evidence that NO may attenuate cardiovascular end-organ responses to sympathetic stimulation. Studies suggest that NO modulates cardiac vagal control, increasing the activity of central vagal motoneurons and, more contentiously, contributing to the bradycardic effects of vagal stimulation. NO also modulates so-called 'indirect' vagal inhibition of sympathetic cardiac responses. Additionally, central attenuation of baroreflex-mediated vagal control has been described. There is relatively little information available on the importance of NO in the regulation of human cardiovascular autonomic control. Further well-controlled studies are required.

Internal mammary artery grafts: the shortest route to the coronary arteries

Inadequate length can limit the use of the internal mammary artery (IMA) for coronary revascularization. By following the shortest route from its origin to the recipient coronary artery, IMA use can be maximized. Seven cadavers were studied to determine that shortest route for the left and right IMAs. The shortest route for the left IMA to the left anterior descending coronary, diagonal, and circumflex coronary arteries was through the pericardium (p less than or equal to 0.01). For the right IMA, the significantly shortest routes were across the anterior heart for the left anterior descending and diagonal arteries, through the right pericardium for the right coronary artery or posterior descending artery, and through the pericardium and transverse sinus for the circumflex artery. Thus, any coronary artery can be reached with an in situ IMA, and the route through the pericardium is markedly shorter to ipsilateral coronary arteries.

Lengthening of rectus muscles in strabismus surgery: with a description of a new muscle clamp

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