Multiorgan MRI findings after hospitalisation with COVID-19 in the UK (C-MORE): a prospective, multicentre, observational cohort study

INTRODUCTION

The multiorgan impact of moderate to severe coronavirus infections in the post-acute phase is still poorly understood. We aimed to evaluate the excess burden of multiorgan abnormalities after hospitalisation with COVID-19, evaluate their determinants, and explore associations with patient-related outcome measures.

METHODS

In a prospective, UK-wide, multicentre MRI follow-up study (C-MORE), adults (aged ≥18 years) discharged from hospital following COVID-19 who were included in Tier 2 of the Post-hospitalisation COVID-19 study (PHOSP-COVID) and contemporary controls with no evidence of previous COVID-19 (SARS-CoV-2 nucleocapsid antibody negative) underwent multiorgan MRI (lungs, heart, brain, liver, and kidneys) with quantitative and qualitative assessment of images and clinical adjudication when relevant. Individuals with end-stage renal failure or contraindications to MRI were excluded. Participants also underwent detailed recording of symptoms, and physiological and biochemical tests. The primary outcome was the excess burden of multiorgan abnormalities (two or more organs) relative to controls, with further adjustments for potential confounders. The C-MORE study is ongoing and is registered with ClinicalTrials.gov, NCT04510025.

FINDINGS

Of 2710 participants in Tier 2 of PHOSP-COVID, 531 were recruited across 13 UK-wide C-MORE sites. After exclusions, 259 C-MORE patients (mean age 57 years [SD 12]; 158 [61%] male and 101 [39%] female) who were discharged from hospital with PCR-confirmed or clinically diagnosed COVID-19 between March 1, 2020, and Nov 1, 2021, and 52 non-COVID-19 controls from the community (mean age 49 years [SD 14]; 30 [58%] male and 22 [42%] female) were included in the analysis. Patients were assessed at a median of 5·0 months (IQR 4·2-6·3) after hospital discharge. Compared with non-COVID-19 controls, patients were older, living with more obesity, and had more comorbidities. Multiorgan abnormalities on MRI were more frequent in patients than in controls (157 [61%] of 259 vs 14 [27%] of 52; p<0·0001) and independently associated with COVID-19 status (odds ratio [OR] 2·9 [95% CI 1·5-5·8]; padjusted=0·0023) after adjusting for relevant confounders. Compared with controls, patients were more likely to have MRI evidence of lung abnormalities (p=0·0001; parenchymal abnormalities), brain abnormalities (p<0·0001; more white matter hyperintensities and regional brain volume reduction), and kidney abnormalities (p=0·014; lower medullary T1 and loss of corticomedullary differentiation), whereas cardiac and liver MRI abnormalities were similar between patients and controls. Patients with multiorgan abnormalities were older (difference in mean age 7 years [95% CI 4-10]; mean age of 59·8 years [SD 11·7] with multiorgan abnormalities vs mean age of 52·8 years [11·9] without multiorgan abnormalities; p<0·0001), more likely to have three or more comorbidities (OR 2·47 [1·32-4·82]; padjusted=0·0059), and more likely to have a more severe acute infection (acute CRP >5mg/L, OR 3·55 [1·23-11·88]; padjusted=0·025) than those without multiorgan abnormalities. Presence of lung MRI abnormalities was associated with a two-fold higher risk of chest tightness, and multiorgan MRI abnormalities were associated with severe and very severe persistent physical and mental health impairment (PHOSP-COVID symptom clusters) after hospitalisation.

INTERPRETATION

After hospitalisation for COVID-19, people are at risk of multiorgan abnormalities in the medium term. Our findings emphasise the need for proactive multidisciplinary care pathways, with the potential for imaging to guide surveillance frequency and therapeutic stratification.

FUNDING

UK Research and Innovation and National Institute for Health Research.

HostSeq: a Canadian whole genome sequencing and clinical data resource

HostSeq was launched in April 2020 as a national initiative to integrate whole genome sequencing data from 10,000 Canadians infected with SARS-CoV-2 with clinical information related to their disease experience. The mandate of HostSeq is to support the Canadian and international research communities in their efforts to understand the risk factors for disease and associated health outcomes and support the development of interventions such as vaccines and therapeutics. HostSeq is a collaboration among 13 independent epidemiological studies of SARS-CoV-2 across five provinces in Canada. Aggregated data collected by HostSeq are made available to the public through two data portals: a phenotype portal showing summaries of major variables and their distributions, and a variant search portal enabling queries in a genomic region. Individual-level data is available to the global research community for health research through a Data Access Agreement and Data Access Compliance Office approval. Here we provide an overview of the collective project design along with summary level information for HostSeq. We highlight several statistical considerations for researchers using the HostSeq platform regarding data aggregation, sampling mechanism, covariate adjustment, and X chromosome analysis. In addition to serving as a rich data source, the diversity of study designs, sample sizes, and research objectives among the participating studies provides unique opportunities for the research community.

Skimming for barcodes: rapid production of mitochondrial genome and nuclear ribosomal repeat reference markers through shallow shotgun sequencing

DNA barcoding is critical to conservation and biodiversity research, yet public reference databases are incomplete. Existing barcode databases are biased toward cytochrome oxidase subunit I (COI) and frequently lack associated voucher specimens or geospatial metadata, which can hinder reliable species assignments. The emergence of metabarcoding approaches such as environmental DNA (eDNA) has necessitated multiple marker techniques combined with barcode reference databases backed by voucher specimens. Reference barcodes have traditionally been generated by Sanger sequencing, however sequencing multiple markers is costly for large numbers of specimens, requires multiple separate PCR reactions, and limits resulting sequences to targeted regions. High-throughput sequencing techniques such as genome skimming enable assembly of complete mitogenomes, which contain the most commonly used barcoding loci (e.g., COI, 12S, 16S), as well as nuclear ribosomal repeat regions (e.g., ITS1&2, 18S). We evaluated the feasibility of genome skimming to generate barcode references databases for marine fishes by assembling complete mitogenomes and nuclear ribosomal repeats. We tested genome skimming across a taxonomically diverse selection of 12 marine fish species from the collections of the National Museum of Natural History, Smithsonian Institution. We generated two sequencing libraries per species to test the impact of shearing method (enzymatic or mechanical), extraction method (kit-based or automated), and input DNA concentration. We produced complete mitogenomes for all non-chondrichthyans (11/12 species) and assembled nuclear ribosomal repeats (18S-ITS1-5.8S-ITS2-28S) for all taxa. The quality and completeness of mitogenome assemblies was not impacted by shearing method, extraction method or input DNA concentration. Our results reaffirm that genome skimming is an efficient and (at scale) cost-effective method to generate all mitochondrial and common nuclear DNA barcoding loci for multiple species simultaneously, which has great potential to scale for future projects and facilitate completing barcode reference databases for marine fishes.

Clinical characteristics with inflammation profiling of long COVID and association with 1-year recovery following hospitalisation in the UK: a prospective observational study

BACKGROUND

No effective pharmacological or non-pharmacological interventions exist for patients with long COVID. We aimed to describe recovery 1 year after hospital discharge for COVID-19, identify factors associated with patient-perceived recovery, and identify potential therapeutic targets by describing the underlying inflammatory profiles of the previously described recovery clusters at 5 months after hospital discharge.

METHODS

The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a prospective, longitudinal cohort study recruiting adults (aged ≥18 years) discharged from hospital with COVID-19 across the UK. Recovery was assessed using patient-reported outcome measures, physical performance, and organ function at 5 months and 1 year after hospital discharge, and stratified by both patient-perceived recovery and recovery cluster. Hierarchical logistic regression modelling was performed for patient-perceived recovery at 1 year. Cluster analysis was done using the clustering large applications k-medoids approach using clinical outcomes at 5 months. Inflammatory protein profiling was analysed from plasma at the 5-month visit. This study is registered on the ISRCTN Registry, ISRCTN10980107, and recruitment is ongoing.

FINDINGS

2320 participants discharged from hospital between March 7, 2020, and April 18, 2021, were assessed at 5 months after discharge and 807 (32·7%) participants completed both the 5-month and 1-year visits. 279 (35·6%) of these 807 patients were women and 505 (64·4%) were men, with a mean age of 58·7 (SD 12·5) years, and 224 (27·8%) had received invasive mechanical ventilation (WHO class 7-9). The proportion of patients reporting full recovery was unchanged between 5 months (501 [25·5%] of 1965) and 1 year (232 [28·9%] of 804). Factors associated with being less likely to report full recovery at 1 year were female sex (odds ratio 0·68 [95% CI 0·46-0·99]), obesity (0·50 [0·34-0·74]) and invasive mechanical ventilation (0·42 [0·23-0·76]). Cluster analysis (n=1636) corroborated the previously reported four clusters: very severe, severe, moderate with cognitive impairment, and mild, relating to the severity of physical health, mental health, and cognitive impairment at 5 months. We found increased inflammatory mediators of tissue damage and repair in both the very severe and the moderate with cognitive impairment clusters compared with the mild cluster, including IL-6 concentration, which was increased in both comparisons (n=626 participants). We found a substantial deficit in median EQ-5D-5L utility index from before COVID-19 (retrospective assessment; 0·88 [IQR 0·74-1·00]), at 5 months (0·74 [0·64-0·88]) to 1 year (0·75 [0·62-0·88]), with minimal improvements across all outcome measures at 1 year after discharge in the whole cohort and within each of the four clusters.

INTERPRETATION

The sequelae of a hospital admission with COVID-19 were substantial 1 year after discharge across a range of health domains, with the minority in our cohort feeling fully recovered. Patient-perceived health-related quality of life was reduced at 1 year compared with before hospital admission. Systematic inflammation and obesity are potential treatable traits that warrant further investigation in clinical trials.

FUNDING

UK Research and Innovation and National Institute for Health Research.

12 Exploring Hospital Discharge as An Opportunity for Falls Prevention Exercise Referral

Topic

Proactive prevention is at the core of the NHS Long Term plan and falls prevention is an important public health priority. National guidance recommends that all health professionals have competence in falls assessment and prevention and advise that older adults at risk of falls are considered for strength and balance exercise.

With rising numbers of older adults occupying inpatient beds, some clinicians may not have the skills to identify these opportunities to prevent falls. Previously, physiotherapy staff on a respiratory medicine ward were not delivering best practice in falls prevention.

Aim

Within 3 months, to achieve a 30% increase in older adults at risk of falls, being offered exercise referral at hospital discharge.

Intervention

Quality improvement methodology including stakeholder engagement and Plan-Do-Study-Act cycles were used to influence behaviour change amongst physiotherapy staff on a respiratory ward. Interventions included training and a documentation sticker. For evaluation, the weekly number of older adults at risk of falls with evidence of offer for falls prevention exercise was collected over 13 weeks and evaluated on a Statistical Process Control chart. Staff confidence scores and cohort data were also recorded and described using descriptive statistics. The NHS Improvement Sustainability Model was used to measure project sustainability.

Improvement

At baseline, 0/18 (0%) older adults had an offer for fall prevention exercise. Over the intervention period, this increased to 22/37 (59.5%) and demonstrated special cause variation that was confidently assigned to the interventions. There was a 44.5% improvement in staff confidence in offering fall prevention exercise. The project scored 53.7% using the NHS sustainability model.

Discussion

This project demonstrated favourable behaviour change in falls prevention practice amongst physiotherapy staff on a respiratory ward. There was variability in the improvement possibly as a result of contextual influences of staffing and seasonality. Hospital discharge is a good opportunity to assess falls risk in older adults and offer information and referral for exercise. Wider implementation may be useful to help older adults optimise health outcomes but will depend on organisational stakeholder support to improve sustainability.

Genetic polymorphisms in toll-like receptors 1, 2, and 4 in feline upper respiratory tract aspergillosis

Fungal species in the genus Aspergillus are environmental saprophytes that can act as opportunistic pathogens of the nasal cavity and paranasal sinuses in humans, cats and other species. Upper respiratory tract aspergillosis (URTA) presents as non-invasive and invasive forms with the latter occurring almost exclusively in immunocompromised hosts. However, in domestic cats, invasive URTA affects apparently immunocompetent patients. A defect in innate immunity has been proposed as a predisposing factor in invasive feline URTA. Single nucleotide polymorphisms (SNPs) in pattern recognition receptor genes have been implicated in the pathogenesis of aspergillosis in humans. The aims of this study were to identify non-synonymous SNPs in the coding regions of toll-like receptors involved in the immune response to Aspergillus spp. and to compare the frequency of these SNPs between affected and control cats. The coding and flanking regions of TLR1, TLR2 and TLR4 were sequenced in 14 cats with URTA and the sequences were compared with those in 20 control cats without aspergillosis. In total, 23 non-synonymous SNPs were identified in TLR1 (n = 11), TLR2 (n = 3) and TLR4 (n = 10). Differences in allelic frequency of non-synonymous SNPs between affected and controls were not identified either within breeds or overall or between non-invasive and invasive disease phenotypes. Although allelic frequency differed between cat breeds that are overrepresented for URTA and underrepresented breeds there was no association differences identified between affected cats and underrepresented breeds. The difference in allelic frequency of an INDEL point mutation identified in intron 1 of TLR4, between cats with non-invasive versus invasive aspergillosis approached significance (p = 0.054). While results from this study do not support a role for non-synonymous SNPs in the pathogenesis of feline URTA they do provide evidence that investigation for polymorphisms in non-coding regions of these genes and in other pattern recognition receptors are warranted.

Breed-specific variations in the coding region of toll-like receptor 4 in the domestic cat

Specific point mutations in the human toll-like receptor 4 (TLR4) confer altered risk for diverse diseases including sepsis, aspergillosis and inflammatory bowel disease. Some of these TLR4 polymorphisms are racially specific. We hypothesised that feline TLR4 polymorphisms might underlie an observed increased risk to infectious and inflammatory diseases in some cat breeds. The aim of this study was to identify breed-specific variations in the coding region of feline TLR4 and to model the effect of mutations on protein structure and function in silico. The entire coding region of TLR4 was sequenced in 8 groups (7 pure-bred, 1 crossbred) of domestic cats (Felis catus) comprising 158 individuals. Twenty-two single nucleotide polymorphisms (SNPs) were identified in TLR4, with 16 located in the coding region (11 non-synonymous) and four in the 3′UTR. Comparison of breed specific allelic frequencies indicated that Burmese and British shorthairs most commonly differed from other breeds. In silico analyses to predict the impact of the 11 non-synonymous variants indicated a deleterious effect on protein structure for one SNP (c.869 G > A), which was not associated with a specific breed. Overall, findings from this study do not support a role of TLR4 dysfunction in breed-predispositions to infectious diseases in domestic cats in Australia.

Abstract P4-09-12: Quantitative image features of nuclear and tubule architecture distinguish high and low oncotype DX risk categories of ductal carcinoma in situ from H&E tissue images

Background: Ductal Carcinoma in Situ (DCIS) is a pre-invasive stage of breast cancer, where malignant cells line the duct but have not spread into other parts of the breast. Oncotype DX (ODX) is a genomic test, which divide patients into three risk of recurrence categories (Low, Intermediate, and High) to help physicians determine if patients require adjuvant therapy. However, ODX is expensive, tissue destructive, and has a turnaround time of 7-10 days. There has been an interest in the use of image analysis of routine H&E histopathology slides to predict the course of the disease; the rationale being that the analytics are able to unearth subtle sub-visual cues regarding disease morphology that may escape visual examination. In this work, we evaluate the role of computer extracted features of nuclear morphology and the necrotic regions from surgically resected specimens to predict ODX categories in patients with DCIS.

Methods: H&E slides from breast tissue of 37 patients who were diagnosed with DCIS and underwent a lumpectomy were acquired. Nine of the 37 had high ODX score (higher than 54), while the rest had a low score (lower than 39). All the slides were digitized on a Philips slide scanner. For each image, a watershed algorithm segmented the individual nuclei, which were used to generate 230 nuclei features including nuclear architecture, nuclear shape and nuclear texture features within each candidate breast duct. In addition, we captured the area of necrosis and empty lumen region inside breast ducts to generate features pertaining to tubule packing.

The average feature values for each patient were calculated across all the breast ducts in each slide. A 3-fold cross validation scheme with 50 repetitions was used with the Support Vector Machine (SVM) classifier to predict the ODX risk category for each patient. We used a covariance algorithm to select the top 4 features that were independent of each other but relevant to the ODX class label.

Results: The top ranked features included features from three categories: nuclei architectural features (standard deviation of triangle area in Delaunay graph, skewness of edge length in Cell Cluster Graph), nuclear texture (standard deviation of Haralick matrix intensity) possibly reflecting chromatin patterns in the cell, and the Tubule Packing Ratio, a measure of the ratio of necrosis area and empty lumen area inside the breast ducts compared to the whole breast duct area. The SVM in conjunction with these 4 features yielded a mean area under receive operator characteristic curve (AUC) of 0.95 in correctly predicting high and low ODX risk categories.

Conclusion: We found that our histomorphometry features pertaining to nuclear arrangement, nuclear texture and necrosis could differentiate between DCIS patients with high and low ODX risk categories. Additional independent validation of the approach is needed to confirm the preliminary findings presented here.

Citation Format: Li H, Whitney J, Thawani R, Gilmore H, Badve S, Madabhushi A. Quantitative image features of nuclear and tubule architecture distinguish high and low oncotype DX risk categories of ductal carcinoma in situ from H&E tissue images [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-09-12.

Evaluation of Serum Aspergillus-Specific Immunoglobulin A by Indirect ELISA for Diagnosis of Feline Upper Respiratory Tract Aspergillosis

Background

Serological tests for diagnosis of aspergillosis in immunocompetent humans and animals are based on Aspergillus‐specific IgG (As‐IgG). In humans with chronic pulmonary aspergillosis, As‐IgA may be detectable even if IgG titers are negative. Cats with upper respiratory tract aspergillosis (URTA) have detectable As‐IgG, but their ability to mount an IgA response and its diagnostic utility are unknown.

Objectives

To determine whether serum As‐IgA can be detected in cats with URTA and evaluate its diagnostic utility alone or combined with As‐IgG.

Animals

Twenty‐three cats with URTA (Group 1), 32 cats with other respiratory diseases (Group 2), and 84 nonrespiratory controls (Group 3).

Methods

Serum As‐IgA and As‐IgG was measured by indirect ELISA. Optimal cutoff values were determined by receiver‐operating curve analysis. Sensitivity (Se) and specificity (Sp) for URTA diagnosis were determined.

Results

Serum IgA was detected in 91.3% of Group 1 cats. The Se of IgA detection was 78.3% and Sp was 96.9% for Group 2, 85.7% for Group 3 and 88.8% for Group 2 and 3 combined. Assay Se for IgG was 100% and Sp was 92.2%. Using combined IgA and IgG results at cutoffs optimized for Sp for IgA and Se for IgG and combined controls (Groups 2 and 3), Se for diagnosis was 100% and Sp was 91.4%.

Conclusion and Clinical Importance

Most cats with URTA have serum As‐IgA antibodies that can be detected by ELISA. Paired measurement of serum As‐IgA and IgG shows no benefit for diagnosis of feline URTA over IgG alone.

Microsatellites for next-generation ecologists: a post-sequencing bioinformatics pipeline

Microsatellites are the markers of choice for a variety of population genetic studies. The recent advent of next-generation pyrosequencing has drastically accelerated microsatellite locus discovery by providing a greater amount of DNA sequencing reads at lower costs compared to other techniques. However, laboratory testing of PCR primers targeting potential microsatellite markers remains time consuming and costly. Here we show how to reduce this workload by screening microsatellite loci via bioinformatic analyses prior to primer design. Our method emphasizes the importance of sequence quality, and we avoid loci associated with repetitive elements by screening with repetitive sequence databases available for a growing number of taxa. Testing with the Yellowstripe Goatfish Mulloidichthys flavolineatus and the marine planktonic copepod Pleuromamma xiphias we show higher success rate of primers selected by our pipeline in comparison to previous in silico microsatellite detection methodologies. Following the same pipeline, we discover and select microsatellite loci in nine additional species including fishes, sea stars, copepods and octopuses.

Amphibia, Plethodontidae, Pseudoeurycea maxima: distribution extension

None.

Collaborative care between professionals and non-professionals in the management of eating disorders: a description of workshops focussed on interpersonal maintaining factors

The aim of this paper is to describe the content and processes involved in a series of workshops for carers of people with an eating disorder. These workshops were designed to equip carers with the skills and knowledge needed to be a 'coach' and help the person with an eating disorder break free from the traps that block recovery. The first hurdle is to overcome the unhelpful patterns of interpersonal processes between the person with an eating disorder and their carers. In both naturalistic studies and randomised controlled trials (RCT), family factors have been implicated either as moderators or mediators of outcome. High levels of expressed emotion (EE), misattributions about the illness or unhelpful methods of engaging with the eating disorder symptoms contribute to this effect. These workshops aim to reduce EE such as over protection. Carers are introduced to the transtheoretical model of change and the principles of motivational interviewing so that they can help rather than hinder change. They learn how to use reflective listening to reduce confrontation and how to sidestep resistance. Carers learn what is needed to help their daughter change by reflecting on the processes involved in changing their own behaviours in relationship with the person with eating disorders. Once they recognise that they may need to change then they can use their skills, information and insight to help change eating disorder symptoms.

Can cognitive exercises help treat anorexia nervosa?

Cognitive remediation therapy (CRT) is used as an intervention for people with brain lesions and psychosis. This case report demonstrates the possible benefits of introducing CRT into treatment packages for anorexia nervosa (AN). In our previous work, we reported that people with AN demonstrate inflexibility in cognitive set-shifting tasks. Weight gain alone does not improve the neuropsychological profile in set-shifting tasks. This case report illustrates how training programmes can address problems in cognitive rigidity. We acknowledge the limitations of case studies, however, this is a starting point in exploring the possibilities of introducing CRT as part of the treatment of AN.

Synthesis and evaluation of GGPP geometric isomers: divergent substrate specificities of FTase and GGTase I

A stereocontrolled synthetic route has been used to prepare two of the geometric isomers of all-trans-GGPP. Neither of these isomers is effective substrates for mammalian GGTase I, but 3 is a potent inhibitor of this enzyme (IC(50)=100 nM). Surprisingly, both compounds are effective substrates for mammalian FTase.

Tandem mass spectrometry studies of green tea catechins. Identification of three minor components in the polyphenolic extract of green tea

Liquid chromatography/electrospray ionization mass and tandem mass spectrometry (MS/MS) techniques were used to identify two minor components and one new compound in the polyphenolic extract of green tea (Camellia sinensis). Identification and structure assignments were based on previously reported sub-structural features in the MS/MS product, precursor and neutral loss scans of reference samples. The structures of two minor components, related to the known green tea components epicatechin gallate (ECG, 5) and epigallocatechin gallate (EGCG, 6), are formed by methylation at the 3"-O-position of the gallic acid moiety. The new compound contained a gallic acid ester group, but had only one phenolic group in either the A- or B-ring, relative to the structure of 5. High-resolution mass measurements supported the empirical formula assigned to the new compounds. An important fragmentation for defining the position of methylation of the ester function involves ionization of the phenolic group at the 4"-position of the gallic acid, followed by elimination of the ester function as a neutral with concomitant formation of the m/z 169 ion. If the 4"-position is blocked by methylation, the formation of m/z 169 incorporating the gallic acid group would be blocked. Thus, the presence of an ion representing the ester group indicates a free 4"-phenol and the absence of this ion would signify the 4"-position as a site of methylation. The operation of this mechanism should be general and useful in assigning the site of methylation of any polyphenolic ester group in natural products. A similar conclusion can be drawn concerning alkylation or esterification of the 4'-position of the catechins, i. e. blocking the 4'-phenol would prevent formation of the m/z 125 ion common to all of the catechin compounds thus far examined. Therefore, mass spectral data are of considerable importance in deducing the sites of alkylation or esterification in the structures of the components of green tea.

Mass spectrometry of 3,5- and 4,5-dicaffeoylquinic acids and selected derivatives

The mass spectral properties of 3,5- and 4,5-dicaffeoylquinic acids (DCQAs) and selected derivatives were examined using electron ionization (EI), fast atom bombardment (FAB) and electrospray ionization (ESI). EI analysis of the trimethylsilyl derivatives provides molecular mass (M(r)) information, but the spectrum is dominated by fragment ions of the caffeic acid group; isomers cannot be differentiated using EI. FAB analysis, in both the positive and negative ion detection modes, provides M(r) information on the free compounds, but little fragmentation is observed using normal scan conditions. The FAB mass-analyzed ion kinetic energy spectroscopic analysis of the free compounds does, however, permit differentiation of the isomers, with 3,5-DCQA showing selective loss of water, a process not observed with the 4,5-isomer. Both EI and FAB provide M(r) and some structural information when applied to the peracetate derivatives of the DCQAs. ESI of the DCQAs provides considerably more structural information, especially in the negative ion detection mode, and is the recommended method of analysis of the quinic acid esters. M(r) information, identity of the ester groups and differentiation of isomers are possible using ESI. Copyright 1999 John Wiley & Sons, Ltd.

Relationship between joint motion and flexor tendon force in the canine forelimb

To increase in vivo tendon force and gliding after flexor tendon repair, a variety of modifications to the methods by which protective passive motion is administered have been advocated. To determine the relationship between the prime variables, wrist and digital position, muscle activation, and in vivo tendon force, a clinically relevant canine model was developed. Force was measured in the flexor tendon during several joint manipulation paradigms: single-finger flexion-extension with the wrist flexed (group 1F), single-finger flexion-extension with the wrist extended (group 1E), four-finger flexion-extension with the wrist flexed (group 4F), four-finger flexion-extension with the wrist extended (group 4E), and synergistic wrist and finger motion where wrist extension and finger flexion were performed simultaneously, followed by wrist flexion and finger extension (group SYN). In addition, tendon force was measured during electric stimulation of the proximal flexor muscle mass. Passive tendon force with the wrist extended (groups 1E and 4E) was two to three times greater than that measured with the wrist flexed, independent of the number of digits moved. With the wrist extended, peak tendon force reached 1,997 g +/- 194 g during single-digit manipulation (group 1E), compared to only 853 g +/- 104 g with the wrist flexed during the same maneuver (group 1F). Statistical comparison between means revealed that groups 1E and 4E were significantly different from groups 1F, 4F, and SYN (p < .005). There were no significant differences between groups 1E and 4E or between groups 1F, 4F, and SYN (p > .200). Active muscle force elicited by electrical stimulation and passive force varied dramatically as the wrist was flexed from full extension 3460 g +/- 766 g to full flexion 427 g +/- 239 g (p < .001). Simultaneously, passive tension decreased from 940 g +/- 143 g with wrist extended to 76 g +/- 37 g with the wrist flexed. These data indicate that wrist position has the greatest effect on flexor tendon force during motions that are commonly used to rehabilitate flexor tendon repairs. Thus, if force is to be controlled during passive motion, wrist-joint angle will have the dominant effect, while the number of digits manipulated will have much less of an effect. If the clinical goal is to minimize tendon force, rehabilitation could be carried out with the wrist flexed, whereas if the goal is to increase tendon force, rehabilitation could include exercise programs that use a greater degree of wrist extension.

Temperature cycler evaluation: what do you need to know?

Which of the 20 different, commercially available, temperature cyclers adequately fulfill all functional requirements? How can an investigator analyze instrument function? This report describes in detail, for the first time, the characteristics of Ericomp temperature cyclers. The data show that the temperature uniformity, accuracy and maximum overshoot is +/- 0.34 degree C, less than 0.5 degree C and 0.17 degree C, respectively. Cycling temperature reproducibility is 0.1%, and cycling time reproducibility is 0.4%. These data compare very favourably to published data describing other temperature cyclers. The techniques used to obtain these data serve as a model for evaluating instruments for well-to-well uniformity, temperature accuracy and within-run reproducibility.

Vanillin, a potential agent for the treatment of sickle cell anemia

Vanillin, a food additive, has been evaluated as a potential agent to treat sickle cell anemia. Earlier studies indicated that vanillin had moderate antisickling activity when compared with other aldehydes. We have determined by high performance liquid chromatography that vanillin reacts covalently with sickle hemoglobin (HbS) both in solution and in intact red blood cells. Hemoscan oxygen equilibrium curves show a dose-dependent left shift, particularly at low oxygen tensions. Rheologic evaluation (pO2 scan Ektacytometry) of vanillin-reacted HbS erythrocytes shows a dose-dependent inhibition of deoxygenation-induced cell sickling. Ektacytometry also suggests that vanillin may have a direct inhibitory effect on HbS polymer formation. Vanillin has no adverse effects on cell ion or water content. X-ray crystallographic studies with deoxyhemoglobin (HbA)-vanillin demonstrate that vanillin binds near His 103 alpha, Cys 104 alpha, and Gln 131 beta in the central water cavity. A secondary binding site is located between His 116 beta and His 117 beta. His 116 beta has been implicated as a polymer contact residue. Oxygen equilibrium, ektacytometry, and x-ray studies indicate that vanillin may be acting to decrease HbS polymerization by a dual mechanism of action; allosteric modulation to a high-affinity HbS molecule and by stereospecific inhibition of T state HbS polymerization. Because vanillin is a food additive on the GRAS (generally regarded as safe) list, and because it has little or no adverse effects at high dosages in animals, vanillin is a candidate for further evaluation as an agent for the treatment of sickle cell disease.

Surface electrical stimulation versus brace in treatment of idiopathic scoliosis

Surface electrical stimulation using the ScoliTron device was applied to 40 adolescent patients for treatment of idiopathic scoliosis. Adequate follow-up was available for 30 of these patients. The overall failure rate was 15 of 30 or 50%. Due to curve progression while using the ScoliTron, these patients either went on to a fusion (9 of 15) or were changed to a brace (6 of 15). The remaining 15 patients were considered successes with no curve progression (10 of 30 or 33%) or successful/failures with slight curve progression not requiring a change in treatment (5 of 30 or 17%). None of the various parameters analyzed were found to be useful indicators of successful treatment using the ScoliTron device. Electrical stimulation was found to be ineffective in preventing curve progression for idiopathic scoliosis.

Fast atom bombardment combined with tandem mass spectrometry for determination of bile salts and their conjugates

Fast atom bombardment desorption of bile salts produces negative ions which show little fragmentation. The lack of fragmentation limits the utility of the method for resolving questions regarding specific structural features. This paper is a report of negative ion fast atom bombardment mass spectra and collision-activated decomposition spectra of cholate, chenodeoxycholate, lithocholate, taurocholate, taurochenodeoxycholate, taurolithocholate, 3 beta-ol-5-cholenate, taurolithocholate-3-sulfate and glycolithocholate-3-sulfate. The collision-activated decomposition spectra are useful for distinguishing bile salt structural features and for quantifying relative amounts of isomeric ions in a mixture. The negative ion mode is well suited for generating anions of bile salts and, when coupled with collisional activation, provides complementary information to the positive ion mode. The collision-activated fragmentation is also unusual as it appears to be an example of reactions occurring remote from the charge site. Furthermore, on the basis of the fragmentations, the charge site can be located in the amphiprotic form of some gas-phase diprotic bile acids such as taurolithocholate-3-sulfate and glycolithocholate-3-sulfate.

In vitro synthesis of vitamin D-3 by cultured human keratinocytes and fibroblasts: action spectrum and effect of AY-9944

With delineation of the photochemical events occurring in the skin after ultraviolet exposure, there has been increased interest in the skin's role in the vitamin D-3-endocrine system. We provide here in vitro conditions for the generation of both labelled (from [3H]acetate) and unlabelled vitamin D-3 in cultures of human keratinocytes and fibroblasts. Sterol precursors and photoproducts in irradiated and non-irradiated cultures are identified by co-chromatography, ultraviolet absorbance spectra, thermal conversion characteristics of previtamin D-3 and mass spectrometry. Because the conversion of 7-dehydrocholesterol to cholesterol is more efficient in vitro than in vivo, the specific delta 7 inhibitor, AY-9944, was added in non-toxic doses to modulate 7-dehydrocholesterol content. Both cell types were equally capable of generating photoproducts, depending on the amount of 7-dehydrocholesterol present. The 290 +/- 5 and 295 nm filters were much more efficient than the 305 nm filter for generating previtamin D-3 and vitamin D-3 in fibroblasts. In contrast, the 305 nm filter was as efficient as the 290 +/- 5 and 295 nm filters in keratinocytes, where it yielded previtamin D-3, with much less lumisterol and tachysterol than appeared with the shorter-wavelength filters. The amount of lumisterol and tachysterol versus previtamin D-3 formed in both cell types was dependent on the total energy applied, with lower energies (less then 1 J/cm2) favoring previtamin D-3 over the other photoproducts. The use of cultured cells provides a system whereby the regulation of vitamin D-3 synthesis by extracutaneous factors can be studied in a homogeneous setting.

The relationship of membrane fluidity to calcium flux in chick intestinal brush border membranes

To evaluate whether membrane fluidity plays a role in regulating calcium flux across the intestinal brush border, we purified brush border membranes from different regions of the chick intestine and determined the relationship of their ability to transport calcium and their fluidity parameters, as determined by diphenylhexatriene fluorescence polarization. Raising the temperature from 4 to 37 C resulted in a 3-fold increase in calcium accumulation by duodenal brush border membrane vesicles (BBMV; 2.85 to 8.70 nmol/mg protein X 12 min). This rise in temperature was associated with a decrease in degree of polarization from 0.395 to 0.290. The methyl esters of cis- and trans-vaccenic acid markedly increased calcium uptake at all temperatures studied (4, 25, and 37 C); the trans isomer was more effective. Both cis- and trans-vaccenic acid lowered the degree of polarization of the BBMV from 0.340 to 0.311 and 0.293, respectively, at 25 C. cis- and trans-vaccenic acid were effective whether BBMV were prepared from vitamin D-deficient chicks or their hatchmates given 1,25-dihydroxyvitamin D [1,25-(OH)2D]. The ability to accumulate calcium correlated to the degree of polarization when calcium uptake by and degree of polarization of BBMV prepared from duodenum, jejunum, and ileum were compared at 25 C. The duodenal BBMV had the greatest calcium accumulation (9.4 nmol Ca/mg protein X 10 min) and the lowest degree of polarization (0.336); the ileal BBMV had the least calcium accumulation (3.5 nmol Ca/mg protein X 10 min) and the greatest degree of polarization (0.375); and the jejunal BBMV were intermediate (8.2 nmol Ca/mg protein X 10 min; 0.344). This rank order was the same whether the intestine was from vitamin D-deficient chicks or their hatchmates given 1,25-(OH)2D before they were killed. 1,25-(OH)2D stimulated calcium uptake by duodenal and jejunal BBMV, reaching a maximal effect at 4 h, but no changes in degree of polarization were observed during this period. A plot of the degree of polarization as a function of the reciprocal of absolute temperature showed an inflection point at approximately 25 C. Neither the slope of the plot nor the point of the inflection was altered by 1,25-(OH)2D. We conclude that chick intestinal BBMV membrane fluidity and calcium uptake correlate in relation to the effects of temperature, changes in membrane lipids, and regional differences in the intestine. However, 1,25-(OH)2D stimulates calcium uptake by BBMV without a detectable change in membrane fluidity.

Vitamin D3 production by cultured human keratinocytes and fibroblasts

We have demonstrated that monolayers of human cultured newborn foreskin keratinocytes and fibroblasts elaborate vitamin D3 following exposure to UV-B. This in vitro system provides a new means to study those factors (hormones, ions, vitamin D3 metabolites, etc.) that regulate the production of vitamin D3 by human skin cells. Vitamin D3 production was enhanced greatly by using cells that were pre-treated with AY-9944, a non-toxic drug that inhibits cholesterologenesis while elevating cellular levels of 7-dehydrocholesterol, the sterol precursor of vitamin D3. The pre-D3 formed within viable, irradiated cells is transformed to D3 within a matter of hours at 37 degrees C, and keratinocytes proved to be more proficient sources of the vitamin and its metabolites than corresponding skin fibroblasts.

The role of conjugation reactions in enhancing biliary secretion of bile acids

Shortening the five-carbon carboxylic acid side chain of cholic acid by one methylene group gave rise to a bile acid (norcholate) that was not a substrate for the bile acid-conjugating enzymes. The metabolism and biliary secretion of norcholate in intact liver was examined in the isolated perfused rat liver system. When rat livers were perfused with 14-20 microM solutions of norcholate for 10 min, norcholate was found in the unconjugated form in liver, venous effluent and bile. Neither tauronorcholate nor glyconorcholate was detectable by high-pressure liquid chromatography or fast-atom-bombardment mass spectrometry. The kinetics of hepatic uptake and biliary secretion of norcholate was compared with that for cholate, taurocholate and chemically synthesized tauronorcholate. The latter three bile acids were completely cleared from the perfusate and efficiently secreted into the bile. However, norcholate was incompletely extracted from the perfusate, and this was shown to be at least partially due to its relatively lower rate of hepatic uptake. Furthermore, the rate of norcholate secretion into bile was greatly reduced relative to the secretion of cholate or chemically synthesized tauronorcholate, even though the concentration of norcholate in the liver was comparatively high. These data demonstrate that the conjugation of bile acids greatly facilitates their secretion into bile.

Human stratum corneum lipids: characterization and regional variations

The lipids of mammalian stratum corneum are known to be important regulators of skin permeability. Since the human stratum corneum displays remarkable regional variations in skin permeability, we assessed the total lipid concentration, the distribution of all major lipid species, and the fatty acid composition in Bligh-Dyer extracts from four skin sites (abdomen, leg, face, and sole) that are known to display widely disparate permeability. Statistically significant differences in lipid weight were found at the four sites that were inversely proportional to their known permeability. In all four sites, among the polar lipids, the stratum corneum contained negligible phospholipids, but substantially more cholesterol sulfate (1-7%) than previously appreciated. As in the stratum corneum from other mammals, the bulk of the lipids consisted of neutral (60-80%) and sphingolipids (15-35%). Of the neutral lipids, free sterols (4- to 5-times greater than esterified sterols), free fatty acids, triglycerides, and highly nonpolar species (n-alkanes and squalene) predominated. n-Alkanes, which were present in greater quantities than previously appreciated, comprised a homologous series of odd- and even-chained compounds ranging from C19 to C34. The sphingolipids comprised over 80% ceramides vs. lesser quantities of glycosphingolipids. In all four sites, the sphingolipids were the major repository of long-chain, saturated fatty acids. The neutral lipid:sphingolipid ratio generally was proportional to the known permeability of each site: higher neutral lipids and lower sphingolipids generally were associated with superior barrier properties. These studies provide: 1) the first detailed, quantitative analysis of human stratum corneum lipids and 2) information about the variability in lipid composition at four skin sites with known differences in permeability. The latter results suggest that variations in neutral lipids, rather than sphingolipids, may underlie local variations in skin permeability.

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