OR07-5 PARP1 Contributes to the Glucocorticoid Receptor Transcriptional Response And Influences the Skeletal Muscle Phenotype

Background

NAD+-dependent PARP1 (Poly-(ADP-ribosyl)polymerase 1) generates the post-translational modification ADP-Ribosylation (ADPR). Given PARP1-ADPR determines cellular NAD+ availability, which in turn impacts a range of hormonally governed actions, we sought to identify the molecular roles of PARP1 in relation to glucocorticoids in the endocrine sensitive tissue skeletal muscle.

Importance: Activity of the glucocorticoid receptor (GR) is dictated by molecular partners whose actions skew the frequency with which GR produces meaningful transcriptional outcomes. As a result, our molecular understanding of this steroid hormone receptor remains incomplete.

Hypothesis

PARP1 through ADPR actions impacts skeletal muscle phenotype and co-regulates glucocorticoid-mediated transcriptional responses.

Experimental Design: Murine muscle myoblasts (C2C12) or primary murine muscle cultures were treated with PARP inhibitors (PJ34(10uM) or BYK204165(1uM)) or transfected with silencing RNA targeting PARP1. Cells were treated with ± dexamethasone (1uM).

Major Results

Analysis of differentiating muscle revealed PARP1 and ADPR are dynamic at days 0-5 (measured by Western immunoblot. p<0.001; n=6). Chemical inhibition of PARP1 significantly decreased ADPR (Western immunoblot. p<0.001; n=9) but did not prevent myotube formation. To identify if initial ADPR dynamics held consequence for fully differentiated myotubes, cells were treated with a single dose of the PARP1 inhibitor BYK204165 at induction of differentiation. Myotube lysates were collected 5 days later and were subjected to unlabelled SWATH-MS. This measured the abundance of 180 proteins as significantly different in PARP inhibitor-treated cells (n=7). Analyses of these proteins revealed over-representation of pathways governing muscle development (FDR 8.99-08), contraction (FDR 9.47-08, myofiber assembly (FDR 8.06-05), and energy metabolism (FDR 2.93-06). Indicating PARP1-ADPR regulates myogenesis and plays a role in the striated muscle contractile response.

ChIP assays for PARP1 binding in cells showed a (30-fold enrichment ±3.2SEM) at GR response elements and detectable ADPR was reduced when exposed to dexamethasone (Western immunoblot n=5). These data support ADPR as responsive to glucocorticoid exposure and PARP1 influences GR recruitment to the genome.

RNAseq of siPARP1 (n=4) versus scrambled myoblasts (n=5) identified differential expression of 165 genes. Gene ontology revealed over-representation in siPARP1 cells of those pathways regulating muscle differentiation, including actin-binding, cytoskeletal structure, and NAD+ binding genes. SiRNA of PARP1 had no influence over the ability of glucocorticoids to activate archetype target genes (DUSP1, MURF1, ATROGIN1 & GILZ), but differentially impacted the expression of 434 other genes.

Conclusions

PARP1 mediated ADPR is critical to the 'early phase' events of muscle cell differentiation. PARP1 influences short-term transcriptional behaviors of the glucocorticoid receptor; in turn, glucocorticoids themselves impact PARP1-genome interaction events. These findings are important for the understanding of general GR mechanisms and have relevance for the widespread functional decline observed during tissue glucocorticoid excess.

Presentation: Saturday, June 11, 2022 12:30 p.m. - 12:45 p.m.

Hypoxia-induced carbonic anhydrase mediated dorsal horn neuron activation and induction of neuropathic pain

ABSTRACT

Neuropathic pain, such as that seen in diabetes mellitus, results in part from central sensitisation in the dorsal horn. However, the mechanisms responsible for such sensitisation remain unclear. There is evidence that disturbances in the integrity of the spinal vascular network can be causative factors in the development of neuropathic pain. Here we show that reduced blood flow and vascularity of the dorsal horn leads to the onset of neuropathic pain. Using rodent models (type 1 diabetes and an inducible endothelial-specific vascular endothelial growth factor receptor 2 knockout mouse) that result in degeneration of the endothelium in the dorsal horn, we show that spinal cord vasculopathy results in nociceptive behavioural hypersensitivity. This also results in increased hypoxia in dorsal horn neurons, depicted by increased expression of hypoxia markers such as hypoxia inducible factor 1α, glucose transporter 3, and carbonic anhydrase 7. Furthermore, inducing hypoxia through intrathecal delivery of dimethyloxalylglycine leads to the activation of dorsal horn neurons as well as mechanical and thermal hypersensitivity. This shows that hypoxic signalling induced by reduced vascularity results in increased hypersensitivity and pain. Inhibition of carbonic anhydrase activity, through intraperitoneal injection of acetazolamide, inhibited hypoxia-induced pain behaviours. This investigation demonstrates that induction of a hypoxic microenvironment in the dorsal horn, as occurs in diabetes, is an integral process by which neurons are activated to initiate neuropathic pain states. This leads to the conjecture that reversing hypoxia by improving spinal cord microvascular blood flow could reverse or prevent neuropathic pain.

18F-GP1 Positron Emission Tomography and Bioprosthetic Aortic Valve Thrombus

BACKGROUND

Bioprosthetic valve thrombosis may have implications for valve function and durability.

OBJECTIVES

Using a novel glycoprotein IIb/IIIa receptor radiotracer 18F-GP1, we investigated whether positron emission tomography (PET)-computed tomography (CT) could detect thrombus formation on bioprosthetic aortic valves.

METHODS

Ex vivo experiments were performed on human platelets and explanted bioprosthetic aortic valves. In a prospective cross-sectional study, patients with either bioprosthetic or normal native aortic valves underwent echocardiography, CT angiography, and 18F-GP1 PET-CT.

RESULTS

Flow cytometric analysis, histology, immunohistochemistry, and autoradiography demonstrated selective binding of 18F-GP1 to activated platelet glycoprotein IIb/IIIa receptors and thrombus adherent to prosthetic valves. In total, 75 participants were recruited: 53 with bioprosthetic valves (median time from implantation 37 months [IQR: 12-80 months]) and 22 with normal native aortic valves. Three participants had obstructive valve thrombosis, and a further 3 participants had asymptomatic hypoattenuated leaflet thickening on CT angiography. All bioprosthetic valves, but none of the native aortic valves, demonstrated focal 18F-GP1 uptake on the valve leaflets: median maximum target-to-background ratio 2.81 (IQR: 2.29-3.48) vs 1.43 (IQR: 1.28-1.53) (P < 0.001). Higher 18F-GP1 uptake was independently associated with duration of valve implantation and hypoattenuated leaflet thickening. All 3 participants with obstructive valve thrombosis were anticoagulated for 3 months, leading to resolution of their symptoms, improvement in mean valve gradients, and a reduction in 18F-GP1 uptake.

CONCLUSIONS

Adherence of activated platelets is a common and sustained finding on bioprosthetic aortic valves. 18F-GP1 uptake is higher in the presence of thrombus, regresses with anticoagulation, and has potential use as an adjunctive clinical tool. (18F-GP1 PET-CT to Detect Bioprosthetic Aortic Valve Thrombosis; NCT04073875).

Aligned Poly-l-lactic Acid Nanofibers Induce Self-Assembly of Primary Cortical Neurons into 3D Cell Clusters

Relative to two-dimensional (2D) culture, three-dimensional (3D) culture of primary neurons has yielded increasingly physiological responses from cells. Electrospun nanofiber scaffolds are frequently used as a 3D biomaterial support for primary neurons in neural tissue engineering, while hydrophobic surfaces typically induce aggregation of cells. Poly-l-lactic acid (PLLA) was electrospun as aligned PLLA nanofiber scaffolds to generate a structure with both qualities. Primary cortical neurons from E18 Sprague-Dawley rats cultured on aligned PLLA nanofibers generated 3D clusters of cells that extended highly aligned, fasciculated neurite bundles within 10 days. These clusters were viable for 28 days and responsive to AMPA and GABA. Relative to the 2D culture, the 3D cultures exhibited a more developed profile; mass spectrometry demonstrated an upregulation of proteins involved in cortical lamination, polarization, and axon fasciculation and a downregulation of immature neuronal markers. The use of artificial neural network inference suggests that the increased formation of synapses may drive the increase in development that is observed for the 3D cell clusters. This research suggests that aligned PLLA nanofibers may be highly useful for generating advanced 3D cell cultures for high-throughput systems.

Prostaglandin E2 Dilates Intracerebral Arterioles When Applied to Capillaries: Implications for Small Vessel Diseases

Prostaglandin E2 (PGE2) has been widely proposed to mediate neurovascular coupling by dilating brain parenchymal arterioles through activation of prostanoid EP4 receptors. However, our previous report that direct application of PGE2 induces an EP1-mediated constriction strongly argues against its direct action on arterioles during neurovascular coupling, the mechanisms sustaining functional hyperemia. Recent advances have highlighted the role of capillaries in sensing neuronal activity and propagating vasodilatory signals to the upstream penetrating parenchymal arteriole. Here, we examined the effect of capillary stimulation with PGE2 on upstream arteriolar diameter using an ex vivo capillary-parenchymal arteriole preparation and in vivo cerebral blood flow measurements with two-photon laser-scanning microscopy. We found that PGE2 caused upstream arteriolar dilation when applied onto capillaries with an EC50 of 70 nM. The response was inhibited by EP1 receptor antagonist and was greatly reduced, but not abolished, by blocking the strong inward-rectifier K+ channel. We further observed a blunted dilatory response to capillary stimulation with PGE2 in a genetic mouse model of cerebral small vessel disease with impaired functional hyperemia. This evidence casts previous findings in a different light, indicating that capillaries are the locus of PGE2 action to induce upstream arteriolar dilation in the control of brain blood flow, thereby providing a paradigm-shifting view that nonetheless remains coherent with the broad contours of a substantial body of existing literature.

The Ion Channel and GPCR Toolkit of Brain Capillary Pericytes

Brain pericytes reside on the abluminal surface of capillaries, and their processes cover ~90% of the length of the capillary bed. These cells were first described almost 150 years ago (Eberth, 1871; Rouget, 1873) and have been the subject of intense experimental scrutiny in recent years, but their physiological roles remain uncertain and little is known of the complement of signaling elements that they employ to carry out their functions. In this review, we synthesize functional data with single-cell RNAseq screens to explore the ion channel and G protein-coupled receptor (GPCR) toolkit of mesh and thin-strand pericytes of the brain, with the aim of providing a framework for deeper explorations of the molecular mechanisms that govern pericyte physiology. We argue that their complement of channels and receptors ideally positions capillary pericytes to play a central role in adapting blood flow to meet the challenge of satisfying neuronal energy requirements from deep within the capillary bed, by enabling dynamic regulation of their membrane potential to influence the electrical output of the cell. In particular, we outline how genetic and functional evidence suggest an important role for G_s-coupled GPCRs and ATP-sensitive potassium (K_ATP) channels in this context. We put forth a predictive model for long-range hyperpolarizing electrical signaling from pericytes to upstream arterioles, and detail the TRP and Ca²⁺ channels and G_q, G_i/o, and G_12/13 signaling processes that counterbalance this. We underscore critical questions that need to be addressed to further advance our understanding of the signaling topology of capillary pericytes, and how this contributes to their physiological roles and their dysfunction in disease.

Coronary 18F-Fluoride Uptake and Progression of Coronary Artery Calcification

Supplemental Digital Content is available in the text.

Background

Positron emission tomography (PET) using ¹⁸F-sodium fluoride (¹⁸F-fluoride) to detect microcalcification may provide insight into disease activity in coronary atherosclerosis. This study aimed to investigate the relationship between ¹⁸F-fluoride uptake and progression of coronary calcification in patients with clinically stable coronary artery disease.

Methods

Patients with established multivessel coronary atherosclerosis underwent ¹⁸F-fluoride PET-computed tomography angiography and computed tomography calcium scoring, with repeat computed tomography angiography and calcium scoring at one year. Coronary PET uptake was analyzed qualitatively and semiquantitatively in diseased vessels by measuring maximum tissue-to-background ratio. Coronary calcification was quantified by measuring calcium score, mass, and volume.

Results

In a total of 183 participants (median age 66 years, 80% male), 116 (63%) patients had increased ¹⁸F-fluoride uptake in at least one vessel. Individuals with increased ¹⁸F-fluoride uptake demonstrated more rapid progression of calcification compared with those without uptake (change in calcium score, 97 [39–166] versus 35 [7–93] AU; P<0.0001). Indeed, the calcium score only increased in coronary segments with ¹⁸F-fluoride uptake (from 95 [30–209] to 148 [61–289] AU; P<0.001) and remained unchanged in segments without ¹⁸F-fluoride uptake (from 46 [16–113] to 49 [20–115] AU; P=0.329). Baseline coronary ¹⁸F-fluoride maximum tissue-to-background ratio correlated with 1-year change in calcium score, calcium volume, and calcium mass (Spearman ρ=0.37, 0.38, and 0.46, respectively; P<0.0001 for all). At the segmental level, baseline ¹⁸F-fluoride activity was an independent predictor of calcium score at 12 months (P<0.001). However, at the patient level, this was not independent of age, sex, and baseline calcium score (P=0.50).

Conclusions

Coronary ¹⁸F-fluoride uptake identifies both patients and individual coronary segments with more rapid progression of coronary calcification, providing important insights into disease activity within the coronary circulation. At the individual patient level, total calcium score remains an important marker of disease burden and progression.

Registration:

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02110303.

Substantial Metabolic Activity of Human Brown Adipose Tissue during Warm Conditions and Cold-Induced Lipolysis of Local Triglycerides

Current understanding of in vivo human brown adipose tissue (BAT) physiology is limited by a reliance on positron emission tomography (PET)/computed tomography (CT) scanning, which has measured exogenous glucose and fatty acid uptake but not quantified endogenous substrate utilization by BAT. Six lean, healthy men underwent ¹⁸fluorodeoxyglucose-PET/CT scanning to localize BAT so microdialysis catheters could be inserted in supraclavicular BAT under CT guidance and in abdominal subcutaneous white adipose tissue (WAT). Arterial and dialysate samples were collected during warm (∼25°C) and cold exposure (∼17°C), and blood flow was measured by ¹³³xenon washout. During warm conditions, there was increased glucose uptake and lactate release and decreased glycerol release by BAT compared with WAT. Cold exposure increased blood flow, glycerol release, and glucose and glutamate uptake only by BAT. This novel use of microdialysis reveals that human BAT is metabolically active during warm conditions. BAT activation substantially increases local lipolysis but also utilization of other substrates such as glutamate.

Multimodality quantitative assessments of myocardial perfusion using dynamic contrast enhanced magnetic resonance and 15O-labelled water positron emission tomography imaging

Kinetic modelling of myocardial perfusion imaging data allows the absolute quantification of myocardial blood flow (MBF) and can improve the diagnosis and clinical assessment of coronary artery disease (CAD). Positron emission tomography (PET) imaging is considered the reference standard technique for absolute quantification, whilst oxygen-15 (¹⁵O)-water has been extensively implemented for MBF quantification. Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) has also been used for MBF quantification and showed comparable diagnostic performance against (¹⁵O)-water PET studies. We investigated for the first time the diagnostic performance of two different PET MBF analysis softwares PMOD and Carimas, for obstructive CAD detection against invasive clinical standard methods in 20 patients with known or suspected CAD. Fermi and distributed parameter modelling-derived MBF quantification from DCE-MRI was also compared against (¹⁵O)-water PET, in a subgroup of 6 patients. The sensitivity and specificity for PMOD was significantly superior for obstructive CAD detection in both per vessel (0.83, 0.90) and per patient (0.86, 0.75) analysis, against Carimas (0.75, 0.65), (0.81, 0.70), respectively. We showed strong, significant correlations between MR and PET MBF quantifications (r=0.83-0.92). However, DP and PMOD analysis demonstrated comparable and higher haemodynamic differences between obstructive versus (no, minor or non)-obstructive CAD, against Fermi and Carimas analysis. Our MR method assessments against the optimum PET reference standard technique for perfusion analysis showed promising results in per segment level and can support further multi-modality assessments in larger patient cohorts. Further MR against PET assessments may help to determine their comparative diagnostic performance for obstructive CAD detection.

Quality control within the multicentre perfusion CT study of primary colorectal cancer (PROSPeCT): results of an iodine density phantom study

OBJECTIVES

To assess the cross-centre consistency of iodine enhancement, contrast-to-noise ratio and radiation dose in a multicentre perfusion CT trial of colorectal cancer.

MATERIALS AND METHODS

A cylindrical water phantom containing different iodine inserts was examined on seven CT models in 13 hospitals. The relationship between CT number (Hounsfield units, HU) and iodine concentration (milligrams per millilitre) was established and contrast-to-noise ratios (CNRs) calculated. Radiation doses (CTDIvol, DLP) were compared across all sites.

RESULTS

There was a linear relationship between CT number and iodine density. Iodine enhancement varied by a factor of at most 1.10, and image noise by at most 1.5 across the study sites. At an iodine concentration of 1 mg ml(-1) and 100 kV, CNRs ranged from 3.6 to 4.8 in the 220-mm phantom and from 1.4 to 1.9 in the 300-mm phantom. Doses varied by a factor of at most 2.4, but remained within study dose constraints. Iterative reconstruction algorithms did not alter iodine enhancement but resulted in reduced image noise by a factor of at most 2.2, allowing a potential dose decrease of at most 80% compared to filtered back projection (FBP).

CONCLUSIONS

Quality control of CT performance across centres indicates that CNR values remain relatively consistent across all sites, giving acceptable image quality within the agreed dose constraints.

KEY POINTS

Quality control is essential in a multicentre setting to enable CT quantification. CNRs in a body-sized phantom had the recommended value of at least 1.5. CTDIs and DLPs varied by factors of 1.8 and 2.4 respectively.

History of myringotomy and grommets

The first recorded myringotomy was in 1649. Astley Cooper presented two papers to the Royal Society in 1801, based on his observation that myringotomy could improve hearing. Widespread inappropriate use of the procedure followed, with no benefit to patients; this led to it falling from favour for many decades. Hermann Schwartze reintroduced myringotomy later in the nineteenth century. It had been realised earlier that the tympanic membrane heals spontaneously, and much experimentation took place in attempting to keep the perforation open. The first described grommet was made of gold foil. Other materials were tried, including Politzer's attempts with rubber. Armstrong's vinyl tube effectively reintroduced grommets into current practice last century. There have been many eponymous variants, but the underlying principle of creating a perforation and maintaining it with a ventilation tube has remained unchanged. Recent studies have cast doubt over the long-term benefits of grommet insertion; is this the end of the third era?

A historical review of head and neck cancer in celebrities

Introduction: The illnesses of celebrity patients always receive more attention from the general public than those of ordinary patients. With regard to cancer, this fact has helped to spread information about the four major malignancies: breast cancer, prostatic cancer, lung cancer and colorectal cancer. Head and neck cancer, on the other hand, is still not well recognised by the lay public, although the risk factors are similar to those of lung cancer. It was the objective of this analysis to identify cases of celebrity patients, the description of which could help to increase awareness of head and neck cancer, its symptoms and risk factors.

Methods: The Internet and medical literature databases were searched for celebrity patients who had suffered from head and neck cancer.

Results: The search revealed numerous famous head and neck cancer patients. However, only seven cases were documented well in the medical literature. Among the identified persons were one emperor, two United States presidents, a legendary composer, a world-renowned medical doctor, an outstanding athlete and an extraordinary entertainer. In spite of their exclusive position in society, these patients did not have a better prognosis compared with ordinary patients of their time. Only two of the group experienced long term survival and only one was cured. None of these influential figures used their influence to fund research or to promote knowledge about their respective diseases.

Conclusion: The identified cases could help increase public awareness of head and neck cancer. Similar to activities in other oncologic fields, current celebrity head and neck cancer patients should be encouraged to discuss their diseases openly, which could have a positive effect on public health.

Tumour targeting of humanised cross-linked divalent-Fab' antibody fragments: a clinical phase I/II study

Antibody engineering has made it possible to design antibodies with optimal characteristics for delivery of radionuclides for tumour imaging and therapy. A humanised divalent-Fab' cross-linked with a bis-maleimide linker referred to as humanised divalent-Fab' maleimide was produced as a result of this design process. It is a humanised divalent antibody with no Fc, which can be produced in bacteria and has enhanced stability compared with F(ab')(2). Here we describe a clinical study in patients with colorectal cancer using humanised divalent-Fab' maleimide generated from the anti-carcinoembryonic antigen antibody A5B7 radiolabelled with iodine-131. Ten patients received an i.v. injection of iodine-131-labelled A5B7 humanised divalent-Fab' maleimide, and positive tumour images were obtained by gamma camera imaging in eight patients with known lesions, and one previously undetected lesion was identified. True negative results were obtained in two patients without tumour. Area under the curve analysis of serial blood gamma counting and gamma camera images showed a higher tumour to blood ratio compared to A5B7 mF(ab')(2) used previously in the clinic, implying this new molecule may be superior for radioimmunotherapy. MIRD dose calculations showed a relatively high radiation dose to the kidney, which may limit the amount of activity that could be administered in radioimmunotherapy. However the reduction in immunogenicity was also a major advantage for A5B7 humanised divalent-Fab' maleimide over murine versions of this antibody suggesting that humanised divalent-Fab' maleimide should be a useful vehicle for repeated therapies.

Community ear care delivery by community ear assistants and volunteers: a pilot programme

Hearing impairment is a major public health problem in Nepal. The present service delivery, however, is mainly hospital based and is limited to large towns. Those people residing in rural areas lack many basic needs including ear care services. The collaborative community volunteer-based ear care pilot programme implemented in Banke, Nepal aims to reach out to those rural areas by establishing sustainable primary ear care services, empowering and utilizing local resources. The focus of the programme is to promote multi-sector improvement in sanitation, nutrition, immunization, breast-feeding and timely care and support to ear patients to help prevent hearing impairment mainly from the sequelae of otitis media.

Towards a national system for monitoring the quality of hospital-based stroke services

BACKGROUND AND PURPOSE

We sought to evaluate a system for monitoring the quality of hospital-based stroke services that uses routinely collected case fatality data, adjusted for case mix, as well as simple measures of the process of stroke care.

METHODS

We compared the process of care and case fatality after stroke between 5 Scottish hospitals (A through E) during 1995-1997. We retrospectively identified 2724 patients with acute stroke using routine discharge data and obtained case mix and process of care data from the medical record. We ascertained case fatality by record linkage and adjusted for case mix using a simple, externally validated regression model.

RESULTS

Crude case fatality varied by 21 deaths per 100 admissions between the 5 hospitals. After adjustment, case fatality still differed significantly (P=0.047), with 5 to 7 more deaths per 100 admissions at Hospital A than at Hospitals B through E. There were major shortcomings in the specialization and organization of care, the use of CT scanning, and the completeness of documentation at Hospital A compared with the other hospitals. There were smaller, but clinically important, differences in care between Hospitals B through E but no significant differences in adjusted case fatality.

CONCLUSIONS

Once adjusted for important prognostic variables, routinely collected case fatality data might identify hospitals with major shortcomings in the processes of stroke care. More moderate, but still clinically important, variations in stroke care can only be identified by monitoring the process of care directly.

Otorhinolaryngology

Otorhinolaryngology, a product of the early 20th century, developed from the joining together of the separate departments of otology, whose practitioners were surgeons, and laryngology which was managed by physicians who also treated diseases of the nose and chest. The 20th century opened with brave attempts to perform skilful surgery under conditions of primitive anaesthesia and no antibiotics. The stimulus of two world wars led to significant advances in technology and greater opportunities to explore new and resurrect old surgical procedures. The discovery of antibiotics saw an end to acute mastoiditis and the complications of otitis media and sinusitis, as well as a decline in the number of tonsillectomy and adenoidectomy operations. Over the last 30 years the specialty has undergone dramatic development and has taken advantage of new advances in endoscopy, microsurgery, the use of lasers, cytotoxic drugs, flap reconstruction and microchip technology. During the same period, although still calling themselves otorinolaryngologists, individual surgeons have subspecialised in otology, otoneurosurgery and skull-base surgery, head and neck surgery, phonosurgery, rhinology and facioplastic surgery, and paediatric otothinolaryngology. Each of these subspecialties has its own societies and specialist journals.

Highlights of the development of ENT in the 20th century

This paper heralds a series entitled The Future of ORL-HNS and Associated Specialties which the Journal will run through each issue of the year 2000.

The distribution and latency of the auditory P300 in schizophrenia and depression

In a study of 19 right-handed patients with positive symptoms of schizophrenia, fulfilling DSM-III-R criteria, a deficit in the left central-temporal distribution of the auditory P300 was shown compared to a group of 31 controls, who showed a symmetrical distribution. In contrast, 14 right-handed patients fulfilling DSM-III-R criteria for major depressive illness without any psychotic features showed a deficit in the right auditory P300 distribution. These changes did not appear to depend on either age, gender or amount of medication. There was an increase in the P300 latency of 22 and 10 ms over that of the controls in schizophrenia and depressive patients, respectively. Only for those with schizophrenia was the increased latency statistically significant. This increased latency in the schizophrenic group did not appear to be related to medication.

Measuring the quality of life of older persons: a model with implications for community and public health nursing

Measuring the quality of life (QOL) of older persons can assist health professionals in achieving a number of important objectives. These include assessing the effects of illness and treatment, identifying need for support services, and developing health enhancing environments. Most QOL models focus unduly on illness and disability, define QOL too narrowly, and do not consider aspects of personal control and potential opportunities for change. A new model of QOL with associated instrumentation, the Quality of Life Profile: Seniors Version (QOLPSV), is described. Administration of the QOLPSV to 205 older persons in Ontario, Canada found it to be reliable and valid. Limitations of the instrument are presented and potential uses explored.

Vocal fold palsy after use of the laryngeal mask airway

We report two cases of left vocal fold palsy following use of the laryngeal mask airway. In both cases anaesthesia was uneventful with a duration of about 60 minutes. It is proposed that high intra-cuff pressures induced during anaesthesia resulted in distension of the hypopharynx and subsequent neuropraxia of the motor branches of the recurrent laryngeal nerve and the external branch of the superior laryngeal nerve.

Co-expression of human protein disulphide isomerase (PDI) can increase the yield of an antibody Fab' fragment expressed in Escherichia coli

Secretion to the periplasm of Escherichia coli enables production of many eukaryotic extracellular proteins in a soluble form. The complex disulphide bond arrangement of such proteins is probably a major factor in determining the low yield of correctly folded product observed in many cases. Here we show that co-expression of human protein disulphide isomerase increased the yield of a monoclonal antibody Fab' fragment in the periplasm of E. coli.

Human protein disulfide isomerase functionally complements a dsbA mutation and enhances the yield of pectate lyase C in Escherichia coli

Human PDI was expressed to the Escherichia coli periplasm, by using a plasmid encoded ompA-PDI fusion under the control of the trp promoter. Periplasmic extracts were shown to contain active PDI using the scrambled ribonuclease assay. PDI activity was also demonstrated by complementation of two phenotypes associated with a dsbA mutation. Alkaline phosphatase activity, which is reduced in dsbA cells, was restored to wild type levels by PDI. PelC, a pectate lyase from Erwinia carotovora, was shown to be DsbA dependent in E. coli. PDI was able to restore its activity to that seen in wild type cells. Increased expression of PDI was found to increase the yield of active PelC above that seen in wild type cells. PDI also enhanced the yield of PelC in DsbA- cells but only in the presence of exogenous oxidized glutathione. PDI is thus able to functionally substitute for DsbA in the folding of disulfide-bonded proteins in the bacterial periplasm and to enhance the yield of highly expressed protein when the ability of the E. coli periplasm to fold protein may be saturated. However, our results suggest that the activities of DsbA and PDI in vivo may be different.

Frailty: a public health perspective

Traditionally, frailty has been conceptualized as reflecting an inevitable decline in abilities usually associated with physical aspects of aging. More recent thinking now sees frailty as reflecting an interaction among individual factors and a range of environmental elements. These emerging models, however, continue to consider frailty as a condition that resides within the individual rather than a situation that exists for the individual. We present a new model that defines frailty as occurring when there is diminished ability to carry out the important practical and social activities of daily living. Factors related to the occurrence of frailty are considered, as are the theoretical and practice implications of viewing frailty as a social construction.

The quality of life of seniors living in the community: a conceptualization with implications for public health practice

Maintaining and improving the quality of life (QOL) of seniors in the community is an increasingly important goal of public health planning and programming. To provide authentic assessments of seniors' quality of life, a partnership of public health workers and university researchers, working closely with seniors in the community, developed the Quality of Life Profile: Seniors Version (QOLPSV). Administration of the QOLPSV to a wide range of North York, Ontario seniors (n = 205) participating in community-based healthful living programs provided evidence of the instrument's psychometric integrity. Additionally, results indicated specific areas of need among seniors, suggesting shifts in emphasis in program delivery. Additional public health applications of a quality of life perspective are outlined.

Canadian approaches to the promotion of health in small workplaces

The promotion of health in small workplaces is particularly challenging. Research was conducted to identify the types of agencies offering prevention and promotion services to small workplaces, and to describe the activities and strategies used to engage this "hard-to-reach" population. This paper reports on a survey of 58 agencies located across Canada. Agencies were mostly of recent origin, many having arisen in response to legislative and other government initiatives, and of two essential types: those that used the workplace as a site for addressing general lifestyle health behaviours, and those addressing the occupational determinants of health. Their location, staffing and program focus reflected their orientation. Factors believed by respondents to influence program effectiveness are summarized. The paper notes the top-down origins of many prevention/promotion efforts, their inherent management bias, and the differing perspectives that underlie the lifestyle and occupational approaches to workplace health. A call for integration of the two approaches is made.

Hearing impairment and ear pathology in Nepal

A stratified random cluster sample of 15,845 subjects was performed in two regions of Nepal to determine the prevalence and main causes of hearing impairment (the most common disability) and the prevalence of ear disease. Subjects reporting current ear pain, or ear discharge, or hearing impairment on direct questioning by a Nepali health worker (primary screening failed), had otoscopy and audiometry (using the Liverpool Field Audiometer) performed, and a questionnaire administered relating to past history. In every fifth house subjects who passed the primary screening (1,716 subjects) were examined to assess the false negative rate of screening. An estimated 16.6 per cent of the study population have hearing impairment (either ear worse than 30 dB hearing threshold level (HTL) 1.0-4.0 kHz, or 50 dB HTL 0.5 kHz), and 7.4 per cent ear drum pathology, equivalent to respectively 2.71 and 1.48 million people extrapolated to the whole of Nepal. Most hearing impairment in the school age group (55.2 per cent) is associated with otitis media or its sequelae. Probably at least 14 per cent of sensorineural deafness is preventable (7 per cent infectious disease, 3.9 per cent trauma, 0.8 per cent noise exposure, 1 per cent cretinism, and 1 per cent abnormal pregnancy or labour). Most individuals reporting current ear pathology (61 per cent) had never attended a health post, and of those receiving ear drop treatment, 84 per cent still had serious pathology. Of subjects who reported ear drop treatment at any time, 31 per cent still had serious pathology. The use of traditional remedies was prevalent.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression, purification and characterization of B72.3 Fv fragments

The Fv fragment of the antibody B72.3 has been produced by expression in both a mammalian and microbial system, namely Chinese hamster ovary (CHO) cells and Escherichia coli. In both cases secretion of the Fv into the culture medium was achieved, with equivalent amounts of Vh and Vl produced. The yield of Fv from CHO cells was 4 mg/l in roller-bottle culture. E. coli proved to be a more productive system with yields of 40 mg/l in shake flasks rising to 450 mg/l in fermentations. B72.3 Fv from both sources was capable of binding to antigen with similar binding ability to the Fab' fragment. A detailed sedimentation analysis, both by velocity and equilibrium techniques, revealed that the two domains of Fv are associated at high concentrations at pH values close to neutral, but dissociate at concentrations lower than approx. 0.5 mg/ml. Individual Vh or Vl polypeptides are not able to bind to the antigen and thus these results suggest that the antigen promotes assembly of Fv at the low concentrations used in the antigen-binding assays. At a pH value of 1.9, Vh and Vl are completely dissociated even at very high concentrations and are apparently unfolded at low solute concentrations. Small-angle X-ray scattering was used to measure a radius of gyration of 1.75 +/- 0.2 nm (17.5 +/- 2 A) for Fv.

Ear surgery camps in Nepal and the work of the Britain Nepal Otology Service (BRINOS)

The Britain Nepal Otology Service (BRINOS), founded as a registered charity in 1988, has so far held four ear surgery camps in Nepal, sponsored and organised a nationwide survey of the prevalence and causes of ear disease and deafness and is sponsoring a pilot scheme of primary care for ear disease. Seven thousand outpatients have been seen, 270 major and 170 minor ear operations have been performed in the four ear surgery camps.

Outpatient Fibreoptic Nasolaryngoscopy and Videostroboscopy

A description of the uses and advantages of fibreoptic nasolaryngoscopy is given together with the applications of videostroboscopy.

Prolonged endotracheal intubation in neonates with hyaline membrane disease

It is well documented that prolonged endotracheal intubation can lead to subglottic trauma and stenosis. Newborn infants with hyaline membrane disease often require assisted ventilation for prolonged periods of time. We examined 11 such children ranging in age from four months to 4.25 years by endoscopy. Some abnormality was found in every child, and in nine there was minor narrowing of the airway.

Sensorineural deafness associated with recessive hypophosphataemic rickets

Two pairs of siblings suffering from recessive hypophosphataemic rickets are presented, three members of which have some degree of sensorineural deafness and all of which have bilateral marked narrowing of the internal auditory canals. The biochemical explanation of the condition is discussed.