Application of an electrocardiography device (iECG) for heart rhythm analysis after exercise in Thoroughbred horses

AliveCor is a smartphone electrocardiography device (iECG) providing automated heart rate (HR) and rhythm determination. Atrial fibrillation (AF) in horses often is paroxysmal and rapid ECG acquisition is needed for diagnostic confirmation. iECGs were collected post-race from 15 horses with AF and 64 horses in sinus rhythm (SR). Results of manual assessment were compared to 3 commercial algorithms for HR and rhythm. Agreement between manually derived HR (HR_M ) and HR derived by the AliveECG Vet (HR_VET ) and Kardia version-1 (K_V1 HR) and Kardia advanced (K_ADV HR) algorithms was quantified by the Bland-Altman limits of agreement test. Agreement between manual rhythm classification and K_V1 and K_ADV algorithms for AF and SR was calculated by the Kappa statistical coefficient. The agreement (bias, 95% limits), between HR_M and HR_VET was 7.1 BPM (-29 to 43) in AF and -4.2 BPM (-38 to 30) in SR, between HR_M and K_V1 HR, was -0.3 BPM (-31 to 30) in AF and 0.2 BPM (-3 to 4) in SR, and between HR_M and K_ADV HR was 7.0 BPM (-29 to 43) in AF and 0.2 BPM (-3.9 to 4.2) in SR. Agreement between manual rhythm classification and K_V1 was 0.36 (0.13-0.59), and K_ADV was 0.84 (0.68-0.99). Sensitivity and specificity for identification of AF and SR of the K_V1 algorithm were 60, 100% and 83, 100%, respectively, and of K_ADV was 87, 100% and 93, 100% respectively. The Kardia algorithms improved precision for HR determination in SR but not AF. The advanced algorithm accurately distinguished between AF and SR. The iECG is suitable for recording episodes of AF following exercise.

Development of a theory-based intervention to increase cognitively able frail elders' engagement with advance care planning using the behaviour change wheel

Background

Advance care planning (ACP) conversations support people to think about, discuss and document their beliefs, values and preferences regarding future care. This process means that should the person loose capacity in the future, care can be provided, consistent with their personal values and beliefs. The ACP process is particularly relevant for older people living with frailty (frail elders) as they are vulnerable to sudden deterioration. However, ACP is rarely undertaken by frail elders. The aim of this study was to develop an intervention to increase multidisciplinary health and social care professionals’ (H&SCPs) engagement of cognitively able, domestic-dwelling frail elders with ACP.

Methods

Intervention development was guided by the Medical Research Council framework for complex interventions and the Behaviour Change Wheel. Multiple methods were used to understand ACP barriers and enablers: a systematic integrative review, a survey (n = 73 H&SCPs), and semi-structured interviews (n = 10 frail elders, n = 8 family members). A conceptual model, developed from the integrative review, underpinned data collection for the survey and interviews. Synthesis of this data, including patient and public involvement, was then used to identify H&SCPs behaviours that needed to change for ACP to be implemented and decide content and implementation for the intervention.

Results

Following the Behaviour Change Wheel system, and based on the findings of the review, survey and interviews, the prototype intervention, Conversations on Living and Dying (CLaD), was developed. The CLaD prototype consisted of one 3.5-hour educational skills session for H&SCPs supported by a toolkit. Content focussed on the relevance of ACP for frail elders, experience of ACP by frail elders, and strategies H&SCPs could adopt to encourage frail elders’ engagement with ACP. Strategies include recognising the importance of relationships and living well now, preparing frail elders for ACP conversations and starting ACP early. Participants who took part in initial prototype refinement reported that the intervention helped them think differently about ACP and encouraged them to engage with frail elders.

Conclusions

The use of behavioural theory enabled the development of CLaD, an evidence-based, theory-driven, person-centred intervention to support ACP engagement with frail elders. While feasibility testing is required, initial prototype refinement demonstrated that H&SCPs found the intervention to be acceptable, engaging, and clinically valuable in their practice with frail elders and their families.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-021-06548-4.

How to design efficient cluster randomised trials

Cluster randomised trials have diminishing returns in power and precision as cluster size increases. Making the cluster a lot larger while keeping the number of clusters fixed might yield only a very small increase in power and precision, owing to the intracluster correlation. Identifying the point at which observations start making a negligible contribution to the power or precision of the study—which we call the point of diminishing returns—is important for designing efficient trials. Current methods for identifying this point are potentially useful as rules of thumb but don’t generally work well. We introduce several practical aids to help researchers design cluster randomised trials in which all observations make a material contribution to the study. Power curves enable identification of the point at which observations begin to make a negligible contribution to a study for a given target difference. Under this paradigm, the number needed per arm under individual randomisation gives an upper bound on the cluster size, which should not be exceeded. Corresponding precision curves can be useful for accommodating flexibility in the choice of target difference and show the point at which confidence intervals around the estimated effect size no longer decrease. To design efficient trials, the number of clusters and cluster size should be determined concurrently, not independently. Funders and researchers should be aware of diminishing returns in cluster trials. Researchers should routinely plot power or precision curves when performing sample size calculations so that the implications of cluster sizes can be transparent. Even when data appear to be “free,” in the sense that few resources are needed to obtain the data, excessive cluster sizes can have important ramifications

Plasma HMGB-1 and Nucleosome Concentrations in Horses with Colic and Healthy Horses

Background

Acute gastrointestinal disease occurs commonly in horses. Novel biomarkers might improve the understanding of SIRS and aid diagnosis and determination of prognosis.

Hypotheses

Increased plasma concentrations of the biomarkers HMGB‐1 and nucleosomes are associated with severity of gastrointestinal lesions in horses; concentrations of these biomarkers will be greater in horses with lesions more likely to cause SIRS; and will provide additional information compared with standard biomarkers fibrinogen and SAA.

Animals

Thirty horses with gastrointestinal disease, 22 healthy horses.

Methods

Prospective study. Plasma samples taken on admission were used for measurement of HMGB‐1, nucleosomes, fibrinogen, and SAA. Values were compared between healthy horses and those with gastrointestinal disease, and between horses with gastrointestinal disease grouped by lesion type (inflammatory, strangulating, and nonstrangulating). Correlations between biomarkers were assessed.

Results

Plasma concentrations of all biomarkers were significantly higher in horses with gastrointestinal disease compared to healthy horses (P ≤ .001). HMGB‐1 and nucleosomes were significantly higher in inflammatory and strangulating groups compared to healthy horses (3.5‐fold and 5.4‐fold increases, respectively, for HMGB‐1 (P < .05) and 4.8‐fold and 5.6‐fold increases for nucleosomes (P < .05)), but concentrations in the group with nonstrangulating disease did not differ from healthy horses. There was significant correlation between HMGB‐1 and nucleosomes (Spearman's r = 0.623; P < .001), and fibrinogen and SAA (Spearman's r = 0.801; P < .001) but not between other biomarkers.

Conclusions and Clinical Importance

High mobility group box‐1 and nucleosomes might have use as biomarkers for horses with gastrointestinal disease. Further studies are required to determine kinetics and prognostic value of serial measurements of these biomarkers in horses.

How many cases of chlamydial infection would we miss by not testing partners for infection?

Quality Improvement Scotland standards for sexual health services require that 0.64 contacts per case should be verified as having attended within 90 days of the first partner notification interview. Partner delivered therapy results in more patients being treated than when patients are given information for partners but removes the possibility of further cases of Chlamydia trachomatis being diagnosed through the tracing of secondary contacts. An audit was performed to estimate the impact of removing secondary contacts on the number of chlamydial infections identified in our service. Patients who were not known to be contacts of chlamydial infection were included. One hundred and twenty-seven index cases generated 189 contacts, of which 100 were confirmed as tested and treated. Sixty-four were C. trachomatis positive, who in turn generated 36 new contacts. Fourteen of these were positive. Secondary contact tracing identified 22-28% more cases of chlamydial infection in our service than if all partners were treated without testing.

Virtual colonoscopy: Issues in implementation

The following issues and requirements related to the implementation of a CT colonography (CTC) service are important: (i) policies are needed regarding the indications for CTC. Concomitant with this is the need for education of potential referrers and patients. Expectations of the procedure, particularly by general practitioners, may be unrealistic and indications for referral may otherwise be inappropriate. At present there is not general acceptance of CTC for screening asymptomatic persons; (ii) a flexible approach to CT protocols is useful, dependent on the indication for and clinical context of referral, the age and body habitus of the patient; (iii) attention to the issues related to the special skills required by the reporting radiologist. While there is a temptation to regard CTC interpretation as an extension of skills used in interpreting other cross-sectional images, there is a need to realise that there are skills required specific to CTC and there should be adequate provision for training; (iv) matters related to reporting, such as reporting format, and lesions that will be reported/not reported; and (v) informed consent from the patient. Information should be provided with regard to the limitations of CTC, the implications of a positive finding and radiation dosage.

Stable aggregates of flexible elements give a stronger link between rays and waves

A recently proposed ray-based method for wave propagation is used to provide a meaningful criterion for the validity of rays in wave theory. This method assigns a Gaussian contribution to each ray in order to estimate the field. Such contributions are inherently flexible. By means of a simple example, it is shown that superior field estimates can result when the contributions are no longer forced to evolve like parabasal beamlets.

Calibration of a 300-mm-aperture phase-shifting Fizeau interferometer

A 300-mm-aperture digital phase-shifting Fizeau interferometer has been developed in-house for precision metrology of optical components fabricated by the optical workshop at Telecommunications and Industrial Physics, Commonwealth Scientific and Industrial Research Organization. We describe the procedures used in the calibration of the instrument. A reference data file representing the deviations from flatness of the reference surface is generated, measurement uncertainty estimated, and aberrations in the instrument assessed. Measurements on 250-mm-diameter uncoated optical surfaces have consistently shown short-term repeatability of 0.3-nm rms from measurement to measurement and allowed for absolute characterization of these surfaces to within a few nanometers.

Apical microsurgery for failed endodontics

The operating microscope allows the surgeon unparalleled visualization of the root end structures for periapical surgery. The ultrasonic root end preparation tips enable debridement of the resected root end 2 to 4 mm in the long axis of the root. These advances have allowed periapical surgery to be performed at a new level of excellence with, we believe, more predictable healing.

Characterization of siglec-5, a novel glycoprotein expressed on myeloid cells related to CD33

We describe the characterization of siglec-5 (sialic acid-binding Ig-like lectin-5), a novel transmembrane member of the immunoglobulin superfamily, highly related to the myeloid antigen, CD33. A full-length cDNA encoding siglec-5 was isolated from a human activated monocyte cDNA library. Sequencing predicted that siglec-5 contains four extracellular immunoglobulin-like domains, the N-terminal two of which are 57% identical to the corresponding region of CD33. The cytoplasmic tail is also related to that of CD33, containing two tyrosine residues embodied in immunoreceptor tyrosine-based inhibitory motif-like motifs. The siglec-5 gene was shown to map to chromosome 19q13.41-43, closely linked to the CD33 gene. When siglec-5 was expressed on COS cells or as a recombinant protein fused to the Fc region of human IgG1, it was able to mediate sialic acid-dependent binding to human erythrocytes and soluble glycoconjugates, suggesting that it may be involved in cell-cell interactions. By using specific antibodies, siglec-5 was found to have an expression pattern distinct from that of CD33, being present at relatively high levels on neutrophils but absent from leukemic cell lines representing early stages of myelomonocytic differentiation. Western blot analysis of neutrophil lysates indicated that siglec-5 exists as a disulfide-linked dimer of approximately 140 kD.

Mode characteristics of twisted resonators composed of two cylindrical mirrors

We examine the optical resonator composed of two astigmatic elements, in a twisted configuration. These cavities have mode cross-sections with principal axes that rotate on propagation. Explicit cavity mode equations are derived for the case of identical mirrors. Such a resonator is appropriate for a solid-state laser that is end-pumped with the output of a laser-diode array brought to a line focus. We present a simple analysis of the significance of rotational misalignment, which effects the pump-to-mode power coupling, beam quality, and cavity stability.

Fluids and electrolytes--clinical aspects

Medical practice rests on the foundation of science. Clinicians are constantly making practical decisions and dealing with immediate situations that demand solutions. Time should be taken to focus on those scientific principles that underlie our diagnostic and therapuetic maneuvers. This section of Pediatrics in Review presents selected topics that are relevant to practice from the areas of physiology, pharmacology, biochemistry, and other disciplines; clarification of these will augment the pediatrician's understanding of clinical procedures.

Interobserver variability in angiographic measurement and morphologic characterization of intracranial aneurysms: a report from the International Study of Unruptured Intracranial Aneurysms

PURPOSE

To determine the variability in assessment of the principal inherent characteristics of intracranial aneurysms through the evaluation of interobserver variability for material with uniform quality.

METHODS

Blinded interpretations of a single set of cerebral arteriograms of 55 aneurysms were evaluated by several statistical approaches.

RESULTS

Excellent correlations were found for the detection and measurement of aneurysms after adjusting for geometric distortion caused by magnification. Progressively decreasing correspondence was found for factors that characterized morphology, including, in order, determination of margins, assessment of accessory appendages, and identification of a neck.

DISCUSSION

Correction for geometric distortion was the most critical factor that influenced uniform measurement of size. Standards for measurement and morphologic characteristics were subsequently established for use in the International Study of Unruptured Intracranial Aneurysms.

Utility of creatinine excretion in body-composition studies of healthy men and women older than 60 y

This study evaluated whether aging alters the usefulness of creatinine excretion as an index of lean body mass (LBM) or muscle mass in healthy men and women. Creatinine excretion was determined while 24 young (15 men and 9 women aged < 32 y) and 38 older (23 men and 15 women aged > 60 y) healthy volunteers stayed at a clinical research center for 3 d. Total LBM was determined by 40K counting in all subjects, and cross-sectional areas of upper arm and thigh muscles were determined in some subjects (10 young, 20 old) by magnetic resonance imaging. The slopes and intercepts of the regression equations relating LBM to average daily creatinine excretion were the same in the younger and older groups, and the precision with which LBM could be determined from creatinine excretion was not diminished by aging. Creatinine excretion was closely correlated with cross-sectional areas of upper arm (r = 0.85) and thigh (r = 0.88) muscles, and the slopes and intercepts of the regression equations were not significantly affected by age. The older group had a mean LBM smaller than that of the younger group, which was accounted for entirely by a smaller muscle mass. Mean resting metabolic rate (RMR), whole-body protein turnover rate, and thigh strength were lower in the older group than in the young group. Adjustment of RMR and protein turnover for creatinine excretion or LBM eliminated the age effects. Strength was lower in the older group even after adjustment for creatinine excretion or LBM. This study indicates that creatinine excretion is useful for evaluating body composition in both young and old subjects.

Vascular lesions in the orbit

Vascular lesions in the postbulbar region of the orbit include hemangiomas, lymphangiomas, dural arteriovenous fistulae, aneurysms, varices, and hematic cysts. The heterogeneous nature of the group indicates the diverse origins of the different entities. Cross-sectional imaging, including computed tomography and magnetic resonance imaging, is used for the majority of these lesions, although special computed tomography and magnetic resonance techniques and selective arteriography occasionally are needed for specific indications.

Pilocytic astrocytomas: well-demarcated magnetic resonance appearance despite frequent infiltration histologically

OBJECTIVE

To determine the magnetic resonance imaging (MRI) characteristics of pilocytic astrocytomas and to correlate them with the histopathologic findings.

MATERIAL AND METHODS

MRI examinations and histopathologic findings in 56 patients with pilocytic astrocytomas were retrospectively reviewed. In 38 patients, findings on MRI were compared with those on computed tomography.

RESULTS

The tumors occurred at all levels of the central nervous system, including the spinal cord. The intracranial tumors were periventricular (73%) or periaqueductal (9%). All tumors were typical pilocytic astrocytomas and were grade 1 on the basis of the World Health Organization classification. At operation, they were often circumscribed and cystic. Radiologically, the tumors were well demarcated (96%), had benign morphologic features, and almost always showed enhancement (94%).

CONCLUSION

MRI of pilocytic astrocytomas typically demonstrated a relatively large, sharply demarcated periventricular mass with pronounced contrast enhancement but minimal or no associated edema. Often, the tumors were cystic on MRI. Despite the well-demarcated appearance grossly and on MRI, pathologic review showed that many of these tumors (64%) infiltrated the surrounding parenchyma, particularly the white matter.

Oligodendrocyte injury is an early event in lesions of multiple sclerosis

The ultrastructural features of 11 stereotaxic brain biopsy specimens that demonstrated inflammatory primary demyelination consistent with acute multiple sclerosis were examined. Uniform widening of inner myelin lamellae (biphasic myelinopathy) and degeneration of inner glial loops ("dying-back" oligodendrogliopathy) were early pathologic abnormalities that antedated complete destruction of myelin sheaths. Perivascular inflammatory cells (lymphocytes, macrophages, and occasional plasma cells) were in intimate contact with degenerating myelin sheaths. The response of astrocytes was prominent, even in areas of minimal demyelination. Oligodendrocytes were morphologically preserved in early lesions but proliferated at the periphery of active lesions. Thinly myelinated axons indicative of central nervous system-type remyelination by oligodendrocytes were observed primarily at the edge of plaques. Disturbances of the myelinating function of oligodendrocytes--unaccompanied by death of these cells--may be among the earliest pathologic features in multiple sclerosis.

The differential diagnosis of orbital calcification as detected on computed tomographic scans

We reviewed 350 orbital computed tomographic scans to determine the frequency, significance, and differential diagnosis of calcified lesions. Of 171 suitable scans that fulfilled the study criteria, 37 (22%) showed calcific densities. The most common intraocular lesion that contained calcium was retinoblastoma, and the most frequently calcified extraocular masses were vascular lesions (hemangioma, lymphangioma, and varix). We describe two orbital tumors--metastatic colonic carcinoma and primary orbital malignant melanoma--that previously have not been reported as having calcification. The presence of calcification within lesions of the lacrimal gland fossa usually, but not always, portends malignant disease.

Spontaneous midbrain hemorrhage: report of seven new cases

Spontaneous midbrain hemorrhage is a unique brain-stem vascular lesion. Sixty-six cases have been reported in the literature, to which we add seven. Of the total of 73 patients reviewed, most presented acutely (66%), but subacute (22%) and chronic onsets (12%) also occurred. Neuro-ophthalmologic abnormalities were found in 88% of patients. Some alteration of consciousness and headache occurred in most patients. Hemiparesis, hemisensory loss, and ataxia were less frequent manifestations. Vascular malformations were suspected or proved in 37% of patients, hypertension was present in 21%, and a bleeding diathesis was noted in 5%. No underlying cause was apparent in 37%. Most patients improved with supportive care only. At follow-up, 23% of patients had no neurologic deficits. In 51% of patients, minor neurologic deficits persisted, related chiefly to cranial nerves III and IV. Moderate deficits persisted in 16% of patients, and 5% of patients died.

Effect of testosterone on metabolic rate and body composition in normal men and men with muscular dystrophy

We have examined the effect of testosterone enanthate injections (3 mg/kg.week, im) on the basal metabolic rate (BMR) estimated by indirect calorimetry and on lean body mass (LBM) estimated by 40K counting in four normal men and nine men with muscular dystrophy. Testosterone treatment increased plasma testosterone levels in all subjects (3-fold mean elevation). BMR increased significantly after 3 months of testosterone treatment (mean, 10%; P less than 0.01; 13% mean increase in the men with muscular dystrophy and 7% mean increase in the normal subjects). BMR remained elevated (mean increase, 9%) after 12 months of testosterone treatment in four men with muscular dystrophy. LBM also was significantly higher after 3 months of treatment (mean, 10%; P less than 0.01) and remained elevated at 12 months. The percent increase in LBM was similar in men with muscular dystrophy (+10%) and normal men (+11%). When BMR was adjusted for the increase in LBM by linear regression, the men with muscular dystrophy had an increase in adjusted BMR after 3 months of testosterone treatment (mean increase, 7%), but not after 12 months. The normal men did not have an increase in adjusted BMR. Testosterone treatment for 12 months slightly reduced body fat, whereas there was an increase in body fat in subjects with muscular dystrophy who were treated with placebo for 12 months. We conclude that there is a significant increase in BMR associated with pharmacological testosterone treatment, which for the most part is explained by the increase in LBM. However, in men with muscular dystrophy, there is a small hypermetabolic effect of testosterone beyond that explained by increased LBM.

Diffuse "fibrillary" astrocytomas: correlation of MRI features with histopathologic parameters and tumor grade

MR images in 54 patients with biopsy-proven diffuse or "fibrillary" astrocytomas were analyzed and compared with the histopathologic features in order to determine which histopathologic characteristics underlie the radiographic findings in these gliomas and whether radiographic findings are more closely correlated with individual histopathologic characteristics than with histologically determined tumor grade. The MRI features studies included tumor heterogeneity, edema, mass effect, border sharpness, "anatomic invasion", contrast enhancement, hemorrhage, and the presence of flow voids, calcium and cyst formation. The histopathologic characteristics studied included cellular atypia, mitoses, cellularity, endothelial proliferation, necrosis and tumor grade. Edema (P less than 0.01), flow voids (P = 0.02) and contrast enhancement (P less than 0.01) demonstrated a direct correlation with tumor grade, but edema (P less than 0.01) and contrast enhancement (P less than 0.01) also demonstrated a significant correlation to tumor cellularity. Tumor heterogeneity was associated with the presence of necrosis (P = 0.01). Hemorrhage occurred only in high grade tumors, where it correlated with endothelial proliferation (P = 0.04).

Epidemiology, bacteriology and control of an outbreak of Nocardia asteroides infection on a liver unit

An outbreak of Nocardia asteroides infection affecting seven patients is described. Over a 5-week period, five patients with liver disease admitted to a ward developed clinical and laboratory evidence of nocardiosis, and two further cases were diagnosed 3 and 5 months later. Three out of the five patients who received specific antimicrobial therapy responded to treatment; in three patients nocardia infection was considered to have contributed to death. In six out of the seven patients, nocardiosis followed immunosuppression. A common-source outbreak was considered to be responsible for infection in the first five patients. In two patients, presentation of infection 5 and 7 months after the first case may have been due to prolonged colonization or subclinical infection with Nocardia. Biotyping of the seven isolates using a fluorogenic biochemical method identified three distinct strains of N. asteroides. The most probable source of Nocardia was contaminated brick and plaster dust arising from building work in an area adjacent to the ward. However, samples of air, dust and water failed to yield N. asteroides. Infection control measures included ward closure followed by thorough cleaning, and formaldehyde fumigation.

Optic nerve sheath meningoceles. Clinical and radiographic features in 13 cases with a review of the literature

Thirteen patients with dilated intraorbital optic nerve sheaths with an expanded, patulous cerebrospinal fluid (CSF) space were studied with high-resolution computed tomography (CT) or magnetic resonance imaging (MRI). Eleven patients had bilateral findings. Headache or visual complaints, or both, were present in all patients. Signs of optic nerve dysfunction were present in eight patients. Three patients had visual acuity worse than 20/200. Cerebrospinal fluid pressure was mildly elevated in two patients. Three patients underwent a surgical procedure; visual acuity improved in one. The authors propose the term meningocele for this condition and suggest MRI with fat-suppression techniques and off-axis sagittal views as the radiographic procedure of choice.

Nocardia infection in patients with liver transplants or chronic liver disease: radiologic findings

The radiologic findings in eight patients with nocardiosis were reviewed. Infection followed liver transplantation in six cases and was associated with chronic liver disease in two. Abnormalities of the chest radiograph predominated and included pleural effusions (n = 6), consolidation (n = 5), cavitating lesions (n = 1), and intrapulmonary nodules (n = 3), but there were no diagnostic features. The diagnosis was made on the basis of bronchial washings (n = 3), skin aspiration (n = 3), pleural fluid (n = 1), and aspiration biopsy of a pulmonary nodule (n = 1). Computed tomography (CT) was helpful in evaluating chest disease in three cases and allowed guided biopsy to obtain material for a definitive diagnosis. In three patients skin lesions in disseminated disease were associated with cerebral lesions seen at CT. A definitive tissue diagnosis is especially important in patients who have received transplants because of malignancy, since the radiologic manifestations of this unusual infection may mimic metastatic recurrence. Conventional radiography and CT are nonspecific but will enable determination of disease extent and selection of the most suitable site for tissue sampling, which is required to confirm the diagnosis.