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.

Risk factors for persistent abnormality on chest radiographs at 12-weeks post hospitalisation with PCR confirmed COVID-19

Background

The long-term consequences of COVID-19 remain unclear. There is concern a proportion of patients will progress to develop pulmonary fibrosis. We aimed to assess the temporal change in CXR infiltrates in a cohort of patients following hospitalisation for COVID-19.

Methods

We conducted a single-centre prospective cohort study of patients admitted to University Hospital Southampton with confirmed SARS-CoV2 infection between 20th March and 3rd June 2020. Patients were approached for standard-of-care follow-up 12-weeks after hospitalisation. Inpatient and follow-up CXRs were scored by the assessing clinician for extent of pulmonary infiltrates; 0–4 per lung (Nil = 0, < 25% = 1, 25–50% = 2, 51–75% = 3, > 75% = 4).

Results

101 patients with paired CXRs were included. Demographics: 53% male with a median (IQR) age 53.0 (45–63) years and length of stay 9 (5–17.5) days. The median CXR follow-up interval was 82 (77–86) days with median baseline and follow-up CXR scores of 4.0 (3–5) and 0.0 (0–1) respectively. 32% of patients had persistent CXR abnormality at 12-weeks. In multivariate analysis length of stay (LOS), smoking-status and obesity were identified as independent risk factors for persistent CXR abnormality. Serum LDH was significantly higher at baseline and at follow-up in patients with CXR abnormalities compared to those with resolution. A 5-point composite risk score (1-point each; LOS ≥ 15 days, Level 2/3 admission, LDH > 750 U/L, obesity and smoking-status) strongly predicted risk of persistent radiograph abnormality (0.81).

Conclusion

Persistent CXR abnormality 12-weeks post COVID-19 was common in this cohort. LOS, obesity, increased serum LDH, and smoking-status were risk factors for radiograph abnormality. These findings require further prospective validation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01750-8.

Who let the dogs out? Therapy dogs in clinical practice

OBJECTIVES

Animal-assisted therapy (AAT) is a growing field in Australia, and therapy dogs are becoming increasingly common in clinical settings. This paper aims to highlight the current issues facing AAT in Australia and to make recommendations on how to progress the field. We acknowledge that there are several ways that therapy dogs may enhance treatment outcomes for clients, such as reductions in stress and acute anxious arousal, and improvements in engagement and rapport. These psychological and physiological advantages, however, may not be sustained once interaction with the dog ceases. Clinicians require adequate training and support to develop and implement interventions that are based on sound theoretical foundations, and take advantage of the adjunctive benefits of animal presence.

CONCLUSIONS

A series of recommendations are made for the professionalisation of AAT, including the development of consensus definitions, clinical governance, accreditation, research and evaluation.

Pharmacology of reflex blinks in the rat: a novel model for headache research

Background

Migraineurs are highly sensitive to the nitric oxide donor glyceryl trinitrate which triggers attacks in many sufferers. In animal studies, glyceryl trinitrate increases neuronal activity in the trigeminovascular pathway and elevates neurotransmitter levels in the brainstem. Many migraineurs also display alterations in blink reflexes, known to involve brainstem circuits. We investigated the effect of GTN on evoked blinks in the anaesthetised rat to determine whether such reflexes may prove useful as the basis for a novel animal model to evaluate potential anti-migraine therapeutic agents.

Method

In anaesthetised rats the electromyogram associated with the reflex blink evoked by corneal airpuff was recorded. Rats were infused with glyceryl trinitrate, sumatriptan plus glyceryl trinitrate or vehicle control. Changes in the magnitude of the reflex blink-associated electromyogram following these treatments were measured.

Results

Glyceryl trinitrate potentiated the evoked reflex blink-associated EMG response from 2 h after infusion. That effect was abolished by simultaneous infusion of sumatriptan with glyceryl trinitrate.

Conclusions

These results show that simple skin surface measurements of evoked electromyographic activity in the rat can reliably detect the evoked blink reflex that can be potentiated by nitric oxide donors. This novel model may be an effective tool for evaluating putative anti-migraine therapeutic agents.

IFN? and CXCR-1 gene polymorphisms in idiopathic bronchiectasis

Idiopathic bronchiectasis is a disease of chronic, bacterial lung infection, unresolving inflammation and progressive lung damage. Bronchiectasis can be associated with autoimmune diseases including ulcerative colitis. Defects of both innate and adaptive immunity have been proposed. The airway inflammation is characterized by interleukin-8 (IL-8) expression and infiltration by neutrophils and T cells. Here we investigated two candidate gene polymorphisms that may contribute to disease susceptibility: a CXCR-1 (+2607 G/C) gene polymorphism that is implicated in IL-8 binding and neutrophil trafficking as well as the interferon-gamma (IFNgamma) (+874 T/A) polymorphism which is linked to levels of IFNgamma production. These polymorphisms were distributed similarly in the idiopathic bronchiectasis group and controls, suggesting that these two candidate gene polymorphisms are not associated with disease susceptibility.

Automated quantitative volumetric breast ultrasound data-acquisition system

This paper describes the development and initial testing of an automated ultrasound imaging technique to acquire quantitative volumetric breast data; the clinical application being breast cancer diagnosis and management. A novel mechanical scanner has been designed and constructed to constrain the breast tissue without compromising the image, to acquire images of the majority of the breast using a conventional B-mode scanner and to maintain patient comfort. An algorithm to improve upon simple depth-dependent amplification by compensating for tissue-dependent attenuation is applied to the images, making the grey-scale values represent local scattering properties more closely. Registration techniques have been developed to correct for geometric errors arising in the data set because of tissue movement and variations in speed of sound in the tissues. The data sets are reconstructed into volumes and viewed interactively. A pilot study of seven patients was performed and selected results are presented to illustrate lesion features. The automated scan reduces operator-dependence, provides clear information on the 3-D tissue boundaries and provides a full record for monitoring or surgical planning.

L-carnitine and exercise tolerance in medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency: a pilot study

Skeletal muscle function may be impaired in patients with medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, but the value of L-carnitine in their long-term management is not clear. This study was designed as a pilot to examine the effects of L-carnitine on exercise tolerance in patients with MCAD deficiency. Four clinically asymoptomatic MCAD-deficient patients, aged 8 to 20 years, were studied. Incremental ramp exercise tests were carried out before and after 4 weeks' treatment with oral L-carnitine (100 mg/kg per day). During exercise without L-carnitine supplementation, plasma carnitine concentrations fell, associated with an increased excretion of urinary acylcarnitines, notably acetylcarnitine, hexanoylcarnitine and octanoylcarnitine. L-carnitine treatment prevented this fall in plasma carnitine and resulted in greater increases in excretion of acylcarnitines. All four patients showed biologically significant improvement in peak oxygen uptake (peak VO2, 18-32% improvement), VO2 at a heart rate of 170 beats/min (15-23% improvement), VO2 at anaerobic threshold (27-42% improvement), and/or oxygen pulse (10-32% improvement). Exercise tolerance in MCAD-deficient patients may be improved by short-term L-carnitine supplementation. This may be the direct result of improved intramitochondrial homeostasis induced by L-carnitine in removing accumulating acyl moieties.

Methylmalonic aciduria: follow-up and enzymology on the original case after 36 years

A 36-year follow-up on the original patient described with methylmalonic aciduria has shown that she has methylmalonyl-CoA apomutase deficiency. The main clinical problem associated with her methylmalonic aciduria is progressive renal impairment requiring commencement of haemodialysis at 42 years of age.

Synthesis of the flavour precursor, alliin, in garlic tissue cultures

The path of synthesis of alkyl cysteine sulphoxides, or flavour precursors, in the Alliums is still speculative. There are two proposed routes for alliin biosynthesis, one is from serine and allyl thiol while the other is from glutathione and an allyl source via gamma glutamyl peptides. The routes have been investigated by exposing undifferentiated callus cultures of garlic and onion to potential pathway intermediates. After a period of incubation of 2 days the callus was extracted, and analysed for flavour precursors and related compounds by HPLC. Standards of alliin, isoallin and propiin were synthesised and their identity confirmed by HPLC and NMR. Putative intermediates selected included the amino acids serine and cysteine, as well as more complex intermediates such as allylthiol, allyl cysteine and glutathione. Both garlic and onion tissue cultures were able to synthesize alliin following incubation with allylthiol, and cysteine conjugates such as allyl cysteine. The ability of the tissue cultures to form alliin from intermediates was compatible with the proposed routes of synthesis of alliin.

Association of HLA-DQ5 and HLA-DR1 with sensitization to organic acid anhydrides

BACKGROUND

Organic acid anhydrides are low molecular weight industrial chemicals, able to cause rhinoconjunctivitis and asthma associated with specific IgE against hapten-carrier protein conjugate. Only a proportion of exposed workers develop IgE-associated allergy to acid anhydrides.

OBJECTIVE

We determined whether genetic susceptibility, in particular, HLA Class II alleles may be a risk factor.

METHODS

We undertook HLA typing in 52 cases who had confirmed specific IgE and in 73 referents matched on site, age and duration of acid anhydride exposure identified in cross-sectional studies of workers exposed to hexahydrophthalic (HHPA), methylhexahydrophthalic (MHHPA) and methyltetrahydrophthalic (MTHPA) anhydrides.

RESULTS

The linked alleles DQ5 (odds ratio [OR]=4.3; 95% confidence interval [95% CI]=1.7, 11) and DR1 (OR 3.0; 95% CI 1.2, 11) were more prevalent in cases than in referents. Within DQ5, DQB1(*)0501 was particularly frequent (OR 3.0; 95% CI 1.2, 7.4).

CONCLUSION

DQB1(*)05 gene confers susceptibility to develop specific IgE antibodies against HHPA, MHHPA and a non-significant trend with MTHPA. DQB1(*)0501 is protective for other low molecular chemical sensitizers (isocyanates and plicatic acid) which may indicate varying affinities for the corresponding specific class II molecules.

Direct gene transfer into plant protoplasts

The techniques of plant molecular biology have advanced rapidly in the last 5 yr, and, for a number of plant species, including some crops, it is now possible to bypass traditional plant breeding techniques and introduce specific genes directly. The earliest reports of the transformation of plants with foreign genes exploited the fact that the soil bacterium Agrobacterium tumefaciens, which induces the formation of crown galls, transfers part of a plasmid (the tumor-inducing, Ti, plasmid) into its host (e.g., ref. 1). The isolation and modification of this plasmid by the insertion of one or more structural genes together with regulatory elements has provided the means of genetically manipulating intact plants, cultured plant tissues, and protoplasts.

Micellar casein gelation at high sucrose content

This article investigates the effect of sucrose addition on the formation of casein gels by acidification and/or renneting of pure micellar casein. Gelation kinetics and gel properties were followed by rheological methods, and microscopy and syneresis measurements were used to obtain a more complete characterization of the structures formed. Sucrose content has been identified as a key parameter for controlling the kinetics of aggregation and the strength of the final gels. Results have shown that the effect of sucrose on gelation can vary such that effects can be completely reversed depending on the gelation route used. During acid gelation, addition of up to 30% (wt/wt) sucrose causes gels to form more rapidly and at higher pH values, and to have higher viscoelastic moduli and a more homogeneous microstructure than those without sucrose. By contrast, gels formed by renneting in the presence of sucrose are weaker and have longer gelation times. It is proposed that sucrose reduces solvent quality and causes the collapse of the "hairy" kappa-casein brush on the surface of the casein micelles. This may explain why sucrose increases the possibility of gel formation during acidification and reduces the degree of kappa-casein hydrolysis during renneting.

Total daily energy expenditure in wasted chronic obstructive pulmonary disease patients

OBJECTIVES

To investigate total daily energy expenditure in chronic obstructive pulmonary disease (COPD) patients during a rehabilitation programme.

DESIGN

Observational study involving a case and a control group.

SUBJECTS

Ten COPD patients (six with body mass index (BMI) <18.5 kg/m(2) and four with BMI >18.5 kg/m(2)) were evaluated for their energy expenditure profile. Four additional healthy age-matched volunteers were also included for methodology evaluation.

INTERVENTIONS

Measurements of total daily energy expenditure (TEE), resting energy expenditure (REE) and diet-induced thermogenesis (DIT) and energy intake were undertaken by indirect calorimetry and bicarbonate-urea methods and dietary records.

RESULTS

REE in COPD patients was not significantly different from that predicted by the Harris-Benedict equation. Before the exercise day the mean TEE was 1508 kcal/day and physical activity level (PAL as calculated by TEE/REE) was 1.52. On the exercise day the TEE increased to 1568 kcal/day and PAL was 1.60, but neither of these changes were significant. The energy cost of increased physical activity during rehabilitation exercise was estimated to be 191 kcal/day. No significant change was found in DIT between the two patient groups. However, overall energy balances were found to be negative (-363 kcal/day).

CONCLUSION

The rehabilitation programme did not cause a significant energy demand in COPD patients. TEE in COPD patients was not greater than in free-living healthy subjects. Patients, who were underweight, did not have a higher TEE than patients with normal weight. This suggested that malnutrition in COPD patients was not due to an increased energy expenditure. On the other hand, a significant negative energy balance due to insufficient energy intake was found in seven out of 10 patients.

Characterization of nitrogen metabolite signalling in Aspergillus via the regulated degradation of areA mRNA

AreA is the principal transcription factor involved in determining nitrogen utilization in Aspergillus nidulans. NH4+ and Gln are utilized preferentially but in their absence, AreA acts to facilitate the expression of genes involved in metabolizing alternative nitrogen sources. It is crucial to the function of AreA that its expression is tightly modulated by the quality and availability of nitrogen sources. One signalling mechanism involves regulated degradation of the areA transcript in response to NH4+ and Gln, which provides the first direct means of monitoring nitrogen signalling in this fungus. Here we assess the specificity of the transcript degradation response, determining that it responds qualitatively to a variety of additional nitrogen sources including Asn. Furthermore, the response to Gln and NH4+ requires the same discrete region of the areA 3'-UTR but both NH4+ and Asn need to be metabolized to Gln before they are effective as a signal. However, NH4+ signalling is independent of AreA activity, unlike Gln and Asn signalling. A mutation in the structural gene for NADP-linked glutamate dehydrogenase, gdhA, which disrupts metabolism of NH4+ to Glu, is additive with mutations in two distinct regions of areA that disrupt the previously identified signalling mechanisms. The triple mutant is both strongly derepressed and expresses very high levels of nitrate reductase activity. These data suggest nitrogen metabolism in A. nidulans is in part regulated in response to the intracellular levels of Gln via the regulated degradation of areA mRNA, but the intracellular Gln level is not the sole determinant of nitrogen metabolite repression.

Nitric oxide potentiates response of trigeminal neurones to dural or facial stimulation in the rat

Infusing glyceryl trinitrate as a donor molecule, we have used electrophysiological and c-fos immunostaining techniques to study the effects of nitric oxide on neurones in the nucleus trigeminalis caudalis. Following infusion of glyceryl trinitrate, responses of neurones to electrical stimulation of periorbital cutaneous afferents were potentiated and threshold for activation of neurones by stimulation of dural afferents was reduced. Expression of c-fos was unchanged by glyceryl trinitrate compared to saline controls. Intradermal injection of capsaicin in the periorbital area increased c-fos expression in nucleus trigeminalis caudalis; this was significantly potentiated by glyceryl trinitrate. These results suggest that, in the anaesthetized rat, glyceryl trinitrate alone may not acutely activate the trigeminovascular system to a significant degree at doses that cause headache and later trigger migraine headache in migraineurs. Nevertheless, it is susceptible to exogenous nitric oxide in that activation of trigeminal neurones through cutaneous or dural pathways is potentiated. This may in some measure underlie the pathogenesis of migraine headache.

Brain-derived neurotrophic factor is released in the dorsal horn by distinctive patterns of afferent fiber stimulation

Brain-derived neurotrophic factor (BDNF) is synthesized by small neuron cell bodies in the dorsal root ganglia (DRG) and is anterogradely transported to primary afferent terminals in the dorsal horn where it is involved in the modulation of painful stimuli. Here we show that BDNF is released in the rat isolated dorsal horn after chemical stimulation by capsaicin or electrical stimulation of dorsal roots. Capsaicin superfusion (1-100 microm) induced a dose-dependent release of BDNF, measured using ELISA. The highest dose of capsaicin also induced a depletion of BDNF protein in the dorsal horn. BDNF release was also seen after electrical stimulation of the dorsal roots at C-fiber strength. This release was encoded by specific patterns of afferent fiber stimulation. Neither continuous low-frequency (480 pulses, 1 Hz) nor tetanic high-frequency (300 pulses in 3 trains, 100 Hz) stimulation evoked release of BDNF, although substance P (SP) release was observed under both of these conditions. However, BDNF was released after short bursts of high-frequency stimulation (300 pulses in 75 trains, 100 Hz) along with SP and glutamate. The NMDA antagonist d-AP-5 inhibited electrically evoked BDNF release. BDNF release was also measured after systemic or intrathecal NGF treatment. This upregulated BDNF content in the DRG and increased the capsaicin-evoked release of BDNF. Similarly, the amount of BDNF released by burst stimulation was increased after NGF treatment. This activity-dependent release continued to be encoded solely by this stimulation pattern. These experiments demonstrate that BDNF release in the dorsal horn is encoded by specific patterns of afferent fiber stimulation and is mediated by NMDA receptor activation.

The Aspergillus nidulans GATA transcription factor gene areB encodes at least three proteins and features three classes of mutation

In Aspergillus nidulans, the principal transcription factor regulating nitrogen metabolism, AREA, belongs to the GATA family of DNA-binding proteins. In seeking additional GATA factors, we have cloned areB, which was originally identified via a genetic screen for suppressors of areA loss-of-function mutations. Based on our analysis, areB is predicted to encode at least three distinct protein products. These arise from the use of two promoters, differential splicing and translation initiating at AUG and non-AUG start codons. All the putative products include a GATA domain and a putative Leu zipper. These regions show strong sequence similarity to regulatory proteins from Saccharomyces cerevisiae (Dal80p and Gzf3p), Penicillium chrysogenum (NREB) and Neurospora crassa (ASD4). We have characterized three classes of mutation in areB; the first are loss-of-function mutations that terminate the polypeptides within or before the GATA domain. The second class truncates the GATA factor either within or upstream of the putative Leu zipper but retains the GATA domain. The third class fuses novel gene sequences to areB with the potential to produce putative chimeric polypeptides. These novel gene fusions transform the putative negative-acting transcription factor into an activator that can partially replace areA.

Artefacts in organic acid analysis: occurrence and origin of partially trimethylsilylated 3-hydroxy-3-methyl carboxylic acids

Previous reports of patients with 3-hydroxy-3-methylglutaric aciduria have described the occurrence of di-trimethylsilyl (TMS) and tri-TMS derivatives of 3-hydroxy-3-methylglutaric acid on analysis using gas chromatography and mass spectrometry, leading to difficulty in quantification and ambiguity in diagnosis. We have extracted organic acids from the urine of patients with 3-hydroxy-3-methylglutaric aciduria using a variety of procedures. Solvent extraction combined with hydrochloric acid/sodium chloride resulted in production of both di-TMS and tri-TMS derivatives of 3-hydroxy-3-methylglutaric acid and also mono-TMS and di-TMS derivatives of 3-hydroxyisovaleric acid. The effects were not abolished by heating. Use of sulphate-based reagents minimised artefact formation and use of DEAE-Sephadex anion exchange extraction resulted in single fully trimethylsilylated derivatives. Artefact formation during use of chloride-based reagents was abolished by pyridine added prior to trimethylsilylation. Chloride ions form adducts with hydroxyl groups in these 3-hydroxy-3-methyl carboxylic acids that prevent complete trimethylsilylation. Chloride-based reagents should be avoided in the solvent extraction of organic acids from physiological fluids or, if used, pre-treatment of the dried extract with pyridine is essential to avoid partial trimethylsilylation of 3-hydroxy-3-methyl carboxylic acids.

A defined sequence within the 3' UTR of the areA transcript is sufficient to mediate nitrogen metabolite signalling via accelerated deadenylation

Nitrogen metabolism in Aspergillus nidulans is regulated by AREA, a member of the GATA family of transcription factors. One mechanism that modulates AREA activity involves the rapid degradation of the areA transcript when sufficient NH4+ or Gln are available. This signalling mechanism has been shown to require a region of 218 nucleotides within the 3' untranslated region of areA mRNA. We demonstrate that this region functions independently in a heterologous transcript and acts to accelerate degradation of the poly(A) tail, which in turn leads to rapid transcript degradation in response to the addition of NH4+ or Gln to the growth medium. areA transcript degradation is inhibited by cycloheximide, but this is not a general consequence of translational inhibition. We believe that this is the first reported example in which specific physiological signals, acting through a defined sequence within a transcript, have been shown to promote accelerated poly(A) degradation, which in turn triggers transcript degradation.

Identification of four novel interleukin-13 gene polymorphisms

The development of allergic asthma is thought to involve environmental and inherited genetic components and has pathophysiological features reflecting in part the activity of T cell cytokines. Interleukin-13, a product primarily of activated lymphocytes, is considered to be a critical effector molecule in allergic airway response and has been found to be overexpressed in the airways of patients with asthma. The IL-13 gene is located on chromosome 5q31, one of the major loci to be linked to asthma susceptibility, and amongst a cluster of genes which dominate the immunopathology of allergic disease. Recently, an IL-13 promoter polymorphism was found to be associated with allergic asthma. In the present study we report the identification of four novel biallelic polymorphisms in the IL-13 gene, two intronic and two exonic, one of which results in a basic to hydrophilic amino acid change. We characterised the frequencies of these four biallelic polymorphisms and the frequencies of the haplotypes, resulting from the combination of these four biallelic polymorphisms, in a population of 196 UK Caucasoid healthy individuals.

Sensitization to oilseed rape is not due to cross-reactivity with grass pollen

BACKGROUND

Oilseed rape is an important crop grown in the UK which can cause specific immunological sensitization with clinical symptoms in a relatively small number of the general population. Individuals with immunoglobulin (Ig) E-mediated allergy to oilseed rape have also been found to be sensitized to other pollen allergens, most frequently being grass pollen. Cross-reactivity between common grass and oilseed rape would have important implications, especially as their flowering period coincides.

OBJECTIVE

We have investigated whether the cosensitization found in individuals sensitized to both oilseed rape and grass pollen is due to cross-reactivity.

METHODS

Cross-reactivity between oilseed rape and grass pollen was determined using RAST, RAST inhibition, Western blotting and inhibition studies with Western blotting.

RESULTS

Competitive RAST inhibition studies between pollen of oilseed rape and grass failed to show any cross-reactivity between the pollen types. Self-inhibition with oilseed rape resulted in 90% inhibition, whereas there was less than 10% inhibition with grass pollen. Western blotting revealed allergens of similar molecular weight in both oilseed rape and grass pollen. Despite allergens of similar molecular weights being present in both pollen types, inhibition immunoblot studies confirmed that the allergens in the two allergens were immunologically distinct.

CONCLUSION

The allergens of oilseed rape and grass pollen, although similar in molecular weights, are immunologically distinct and there is no evidence of cross-reactivity between them. Individuals allergic to grass pollen will not necessarily develop a specific nasal or airway response to inhaled oilseed rape pollens.

Abnormal substance P release from the spinal cord following injury to primary sensory neurons

The neuropeptide substance P (SP) modulates nociceptive transmission within the spinal cord. Normally, SP is uniquely contained in a subpopulation of small-calibre axons (Adelta- and C-fibres) within primary afferent nerve. However, it has been shown that after nerve transection, besides being downregulated in small axons, SP is expressed de novo in large myelinated Abeta-fibres. In this study we investigated whether, following peripheral nerve injury, SP was released de novo from the spinal cord after selective activation of Abeta-fibres. Spinal cords with dorsal roots attached were isolated in vitro from rats 2 weeks following distal sciatic axotomy or proximal spinal nerve lesion (SNL). The ipsilateral dorsal roots were electrically stimulated for two consecutive periods at low- or high-threshold fibre strength, spinal cord superfusates were collected and SP content was determined by radioimmunoassay. SNL, but not axotomized or control rat cords, released significant amounts of SP after selective activation of Abeta-fibres. Not only do these data support the idea that Abeta myelinated fibres contribute to neuropathic pain by releasing SP, they also illustrate the importance of the proximity of the lesion to the cell body.

Tissue-specific galactosyltransferase abnormalities in an experimental model of rheumatoid arthritis

OBJECTIVE

To investigate whether the observed pathophysiological similarities that develop in both the collagen induced experimental model of arthritis (CIA) and rheumatoid arthritis (RA) are associated with similar glycosylation changes, and to evaluate possible differences in the relative activity of the glycosylation enzyme beta, 1-4 galactosyltransferase (GTase) within various tissues, and thus provide a new insight into the potential pathogenic mechanisms controlling glycosylation changes.

METHODS

Lymphocytic membrane-bound GTase activity was examined in 30 mice with CIA, 30 age matched controls and 10 adjuvant treated non-arthritic DBA/1 mice. Tissue-specific changes were assessed by comparison of GTase activity in peripheral (P.GTase) and paired splenic lymphocytes. In addition, we also investigated the effect that these changes may exert on the overall extracellular level of this enzyme, by assaying serum GTase (S.GTase) activity in these and a further group of 27 arthritic and 20 control mice. To analyse this synthetic abnormality in greater depth and to investigate the relevance of these glycosylation changes to the pathogenesis of arthritis, we also examined the humoral regulatory component associated with this system by assaying for both anti-collagen as well as anti-GTase antibodies.

RESULTS

The induction of arthritis in DBA/1 mice results in a marked reduction in P.GTase activity, compared with age-matched unimmunised mice and the adjuvant controls. In contrast to the P.GTase, splenic GTase activity was found to be similar in all the groups examined. Correspondingly, serum GTase activity was also found to be significantly lower in the collagen induced arthritic mice. This overall reduction in beta, 1-4 GTase activity reflects the clinical severity of arthritis and is associated with increased levels of naturally occurring anti-GTase antibodies.

CONCLUSIONS

The GTase defect seen in the peripheral B and T cells in rheumatoid arthritis is also evident in the arthritic DBA/1 mouse model of RA. This may indicate a common pathological process in both rheumatoid disease and CIA, in which changes in glycosylation are dependent on the aberrant modulation of GTase in circulating, but not splenic lymphocytes. The relative expression and activity of glycosyltransferases within various tissues may not only contribute to immunoglobulin G (IgG) glycosylation changes, but perhaps also the aberrant expression of cell surface carbohydrates and thus cell trafficking.

Improvement in exercise tolerance in isovaleric acidaemia with L-carnitine therapy

The effect of 4 weeks' treatment with oral-L-carnitine (100 mg/kg per day) on carnitine status and metabolic parameters during an incremental ramp exercise test in a 12-year-old girl with isovaleric acidaemia was examined to determine its possible therapeutic role. The maximum work rate achieved increased from 110 to 120 watts; oxygen consumption at anaerobic threshold from 600 to 800 L/min; peak oxygen consumption from 1270 to 1450 L/min; and oxygen pulse, a measure of cardiac output, from 7.0 to 8.1 L/beat. These changes were associated with increases in plasma and urinary free and acyl carnitine concentrations but no change in physical activity. This observed effect of L-carnitine on exercise performance may be on cardiac or skeletal muscle function or both. We conclude that, in this single patient with isovaleric acid-aemia, L-carnitine supplementation had objective benefits and further studies on more patients are warranted.

Pleural fluid pseudouridine in malignant and benign pleural effusions

Pseudouridine in urine and plasma has been proved to be a useful tumour marker in many malignant conditions. We studied its usefulness in pleural fluid for distinguishing malignant from non-malignant pleural effusions. Pleural fluid pseudouridine concentrations in different groups of patients with pleural effusion (31 malignant, 29 benign, 16 unknown, 1 double pathology) was measured and compared. Its usefulness in distinguishing malignant from non-malignant pleural effusions was analysed by receiver-operating characteristic (ROC) curve analysis. Pseudouridine concentrations in the malignant group were significantly higher than the non-malignant group (P < 0.017, Bonferroni adjustment) with values overlapping extensively at the lower end. The area-under-the curve (AUC) value in the ROC curve analysis was 0.675 (P < 0.05). We conclude that the pleural fluid pseudouridine is of limited clinical value in distinguishing malignant from non-malignant pleural effusion due to its extensive overlap. However, it is useful when the concentration is higher than 65 mumol/L, which indicates malignancy.

Reduced adenosine uptake accelerates ischaemic block of population spikes in hippocampal slices from streptozotocin-treated diabetic rats

We have used rats with streptozotocin-induced diabetes to investigate the effects of hyperglycaemia-mediated impaired nucleoside uptake on the actions of endogenous adenosine in hippocampal slices. In control tissue under conditions of anoxia and aglycaemia the rise in the extracellular adenosine concentration resulted in complete inhibition of synaptic activity in about 2 min. In slices from previously hyperglycaemic rats the inhibition of synaptically mediated responses occurred significantly faster, although this change could be prevented by insulin treatment. Application of the selective adenosine A1 receptor antagonist [8-cyclopentyl-1,3-dipropylxanthine (DPCPX)] prevented the anoxia/aglycaemia-mediated inhibition and, furthermore, abolished the differences in the electrophysiological responses between control and diabetic tissue. The effects of impaired nucleoside uptake could be mimicked in control slices by applying the nucleoside uptake blocker hydroxynitrobenzylthioinosine (HNBTI). This had the effect of speeding up the rate of anoxia/aglycaemia-induced synaptic inhibition in control tissue to that seen in diabetic tissue. However, such treatment had no effect on the responses in diabetic tissue as expected if the HNBTI-sensitive uptake process was already inhibited by the chronic hyperglycaemia. The impairment of nucleoside uptake by chronic hyperglycaemia results in the potentiation of the modulatory actions of endogenous adenosine in the central nervous system. Such an alteration in adenosine function may be important in explaining behavioural and pathological changes associated with diabetes mellitus.

Enzymatic synthesis of the glycosides of calystegines B1 and B2 and their glycosidase inhibitory activities

Several glycosides of calystegines B1 and B2 were synthesized by use of rice alpha-glucosidase and the whole cells of Rhodotorula lactosa, and their glycosidase inhibitory activities were investigated. Incubation of mixture of calystegine B1 and maltose with rice alpha-glucosidase gave 3-O-alpha-D-glucopyranosylcalystegine B1 (2, 11.3%). An enzymatic beta-transglucosylation reaction of calystegines B1 or B2 with cellobiose using the whole cells of R. lactosa gave 3-O-beta-D-glucopyranosylcalystegine B1 (1) (0.9%) or 4-O-beta-D-glucopyranosylcalystegine B2 (3, 11.2%), respectively, while similar beta-transgalactosylation of calystegine B2 from lactose gave 4-O-beta-D-galactopyranosylcalystegine B2 (4, 10.1%). The glycosylation of calystegines B1 and B2 markedly decreased or abolished their inhibition against beta-glucosidase, alpha- or beta-galactosidase. Compound 4 however retained more or less the potency of calystegine B2 against trehalase. Interestingly, compound 1 was a noncompetitive inhibitor of rice alpha-glucosidase, with a Ki value of 0.9 +/- 0.1 microM.

Telemedicine and the national information infrastructure: are the realities of health care being ignored?

Health care is shifting from a focus on hospital-based acute care toward prevention, promotion of wellness, and maintenance of function in community and home-based facilities. Telemedicine can facilitate this shifted focus, but the bulk of the current projects emphasize academic medical center consultations to rural hospitals. Home-based projects encounter barriers of cost and inadequate infrastructure. The 1996 Telecommunications Act as implemented by the Federal Communications commission holds out significant promise to overcome these barriers, although it has serious limitations in its application to health care providers. Health care advocates must work actively on the federal, state, and local public and private sector levels to address these shortcomings and develop cost effective partnerships with other community-based organizations to build network links to facilitate telemedicine-generated services to the home, where the majority of health care decisions are made.

Identification of the major water/salt insoluble wheat proteins involved in cereal hypersensitivity

BACKGROUND

Several studies have investigated water/salt soluble proteins which comprise 50% of the proteins in wheat. The remaining 50% of wheat proteins, are water/salt insoluble proteins of which there is limited information on their role in cereal hypersensitivity.

OBJECTIVES

To investigate the allergenicity of the water/salt insoluble gliadin and glutenin proteins (prolamins).

METHODS

RAST, electrophoresis and Western blotting were used to identify water/salt insoluble wheat allergens. Competitive RAST inhibition was conducted to investigate cross-reactivity between prolamins and water/salt soluble wheat proteins.

RESULTS

Specific IgE to alpha-gliadin and to total glutenins were detected in all sera. IgE to beta-, gamma-, fast omega-, and slow omega-gliadin were present in lower numbers of sera. Prolamin allergens of 90-11 kDa were identified by immunoblotting. Water/salt soluble proteins crossreacted with alpha-gliadin and total glutenins.

CONCLUSIONS

Individuals who are hypersensitive to water/salt soluble wheat proteins produce specific IgE to water/salt insoluble wheat proteins. Western blotting has shown that gliadins, glutenins and proteins with similar molecular weights as the endogenous water/salt soluble wheat enzyme inhibitors are important allergens. Alpha and fast omega- are the most allergenic gliadins. The water/salt insoluble proteins share cross-reacting epitopes with water/salt soluble proteins. These data show that the numbers of proteins involved in the development of cereal hypersensitivity is greater than previously believed and that the development of specific IgE to alpha-gliadin may in part depend on the presence of cross-reacting antibodies to water/salt soluble flour allergens.

Age-related differences in an ecologically based study of route learning

Spatial learning abilities in younger adults and in healthy elderly adults were examined in 2 tasks. In the first task, participants were tested for their ability to recall relevant route information as well as to recognize and to order temporally landmark information observed along the route. Older participants had relatively greater difficulty retracing the route and temporospatially ordering landmarks but were equally good at recognition of landmarks occurring on the route. In the second task, participants memorized a 2-dimensional representation of a route and subsequently navigated the route from memory. Older participants had greater difficulty memorizing the route and navigating it. Errors of omission, commission, wrong, and forced choice were analyzed. Group differences in the pattern of errors differed by task.

Subtractive hybridization of cDNA from small amounts of plant tissue

A subtractive hybridization method is described that allows the generation of a subtractive gene library from small amounts of plant or other eukaryotic tissues. The method uses paramagnetic oligo-dT beads to capture poly-adenylated mRNA and to synthesize the complementary cDNA on a solid support. The use of magnetic beads facilitates the change of reaction buffers and the removal of primers and minimizes yield losses. Subtracted material obtained from this method can either be cloned directly or used to screen a specific library.

Age-related differences in an ecologically based study of route learning

Spatial learning abilities in younger adults and in healthy elderly adults were examined in 2 tasks. In the first task, participants were tested for their ability to recall relevant route information as well as to recognize and to order temporally landmark information observed along the route. Older participants had relatively greater difficulty retracing the route and temporospatially ordering landmarks but were equally good at recognition of landmarks occurring on the route. In the second task, participants memorized a 2-dimensional representation of a route and subsequently navigated the route from memory. Older participants had greater difficulty memorizing the route and navigating it. Errors of omission, commission, wrong, and forced choice were analyzed. Group differences in the pattern of errors differed by task.

Glucuronidase Expression in Transgenic Tobacco Roots with a Parasponia Promoter on Infection with Meloidogyne javanica

The expression of a g-us reporter gene linked to a Parasponia andersonii hemoglobin promoter has been studied in transgenic tobacco plants after infection by Meloidogyne javanica. Transgenic roots were harvested at different times after nematode inoculation, and stained histochemically for expression of the gus gene. During the early stages of infection (0-2 weeks) there was little expression in giant cells, in contrast to other cells of the root. In later stages of infection (3-6 weeks) there was strong gus expression in giant cells, with virtually no expression in other cells of the root. The Parasponia hemoglobin promoter therefore appears to direct down-regulation of linked genes on induction of giant cells, but up-regulation in mature giant cells. This reflects different metabolic activities in the giant cells depending on their stage of development. The Parasponia hemoglobin promoter may respond to oxygen tension in giant cells. This suggests that oxygen tension may be limited in the metabolically active giant cells that are associated with egg-laying females.

New avenues in 3-D computerised (stereopathological) imaging of breast cancer (review)

Multimodal methods of three-dimensional (3-D) imaging of breast cancer are described. These involve scanning confocal microscopy, using 50 MHz acoustic or near-infrared images, four-view (tetrahedral) radiography and x-ray projection microscopy. Computerised volume data from these techniques can be used to produce three-dimensional images of tissue ranging from 500 microns to approximately 4 mm in thickness. Preliminary findings indicate that stereoscopic images or 3-D computerised reconstructions are capable of advancing the understanding of the structure of ductal carcinoma in situ, lesions simulating microinvasive breast carcinoma, surgical clearance of high-grade calcifying ductal carcinoma in situ, and the 3-D growth patterns of invasive forms of breast carcinoma. In the future computerised image fusion techniques seem likely to be able to take advantage of multimodal imaging of breast cancers, thus correcting primary imaging artefacts, improving robustness, and combining complementary information. In addition, the use of computerised tetrahedral radiography may change the intraoperative assessment of breast cancers, which mostly depend at present upon subsequent laboratory procedures that take days to perform.

Stereoselective effects-of 2,3-benzodiazepines in vivo: electrophysiology and neuroprotection studies

The stereoselectivity and potency of 3N-substituted 2,3-benzodiazepines were examined in vivo against excitation of spinal neurones induced by electrophoretic ejection of N-methyl-D-aspartate (NMDA), alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) and kainate in anaesthetised rats. AMPA receptor antagonist activity resided in the (-) isomers, LY300164 and LY303070, which were effective given electrophoretically, intravenously (2.5-5 mg/kg) or orally (10 mg/kg). The same stereoselectivity was observed in neuroprotection studies. Thus, systemic administration of the (-) isomer, but not the (+) isomer, of these 2,3-benzodiazepines before or immediately after bilateral carotid artery occlusion in the gerbil was neuroprotective. For example, 10 mg/kg of LY300164 intraperitoneally or orally provided survival of up to 25% of hippocampal CA1 neurones.

The role of glycine in anoxia/aglycaemia-induced potentiation of N-methyl-D-aspartate receptor-mediated postsynaptic potentials in the rat hippocampus

During brain ischaemia there is a sustained increase in extracellular glycine levels, and the potential role of these changes in modulating N-methyl-D-aspartate (NMDA) receptor-mediated activity following an anoxic/aglycaemic insult was studied in the rat hippocampal slice. Addition of large saturating concentrations of glycine (100 microM and 1 mM) to the superfusate resulted in increased extracellularly recorded NMDA receptor-mediated components of excitatory postsynaptic potentials (EPSPs) recorded in area CA1. The effects of added glycine were strychnine-insensitive and blocked by a competitive NMDA antagonist. Anoxic/aglycaemic insults to the tissue caused persistent increases in NMDA receptor-mediated EPSPs, but the magnitude of the observed upregulation was unaffected by the presence of added saturating concentrations of glycine. The data suggests that alterations in glycine levels after oxygen deprivation are not responsible for the long term modulation of NMDA receptor activity.

Nucleotide and deduced amino acid sequence of the 3' end of the BYMV-MI genome

We have cloned and sequenced cDNA transcribed from the 3' 1,239 nucleotides of the genomic RNA of a Western Australian isolate (MI) of bean yellow mosaic potyvirus (BYMV). This sequence contains 246 nucleotides of the NIb (replicase) gene and 819 nucleotides representing the entire coding region of the viral coat protein gene, followed by a 3' non-coding region of 174 nucleotides. The coding region of the coat protein gene is identical in length (273 amino acids) to that already reported for other isolates of this virus. The sequence identities obtained for BYMV-MI and published sequences of BYMV isolates range between 85% and 92% for the coding region of the coat protein and 90% to 98% for the 3' non-coding region. Likewise, the region of the NIb gene sequenced shows 99% and 97% sequence identity in the deduced amino acid and the nucleotide sequences, respectively.

Estimating energy expenditure from specific activity of urine urea during lengthy subcutaneous NaH14CO3 infusion

Five healthy male subjects were continuously infused subcutaneously with [14C]bicarbonate (12.3 microCi/day) using a mini pump for 5 days while in a whole body calorimeter. Energy expenditure was varied over a range of 1.35-1.75 times basal metabolic rate. Urine collections were obtained throughout the study and used to measure the specific activity of urea, from which CO2 production was estimated. It was assumed that the recovery of label in gaseous CO2 was 95% of that infused and that the specific activity of urea was 85% that of expired CO2. Continuous daily collections of calorimeter air revealed that 95.6 +/- 1.3% (SD) of infused label was recovered as gaseous CO2, with little daily variation. Another 1.5 +/- 0.4% was recovered as urinary urea. The estimated CO2 production, calculated from the specific activity of urea in 24-h urine samples corrected for the small effects due to changes in the size and specific activity of the urea pool, was found to be 100 +/- 5% of the calorimeter estimate for 1-day periods (20.80 +/- 1.44 mol CO2/day) and 100 +/- 2% for 4-day periods. This study suggests that, in healthy subjects, the labeled [14C]bicarbonate-urea method can provide reasonable estimates of net CO2 production over the range examined.

The binding of synovial tissue-derived human monoclonal immunoglobulin M rheumatoid factor to immunoglobulin G preparations of differing galactose content

There are several sites on IgG Fc that have been reported to be the epitopes for binding rheumatoid factors (RF). It is now established that there are alterations in the oligosaccharides on IgG from patients with rheumatoid arthritis and it has been suggested that these changes may enhance immune complex and cryoglobulin formation. We have used a series of IgG preparations differing in their content of oligosaccharide chains lacking galactose from 18 to 86% to determine whether changes in sugar content affect the binding of rheumatoid factor. Five of 16 monoclonal rheumatoid factors prepared from synovial tissue, from patients with juvenile or adult rheumatoid arthritis, bound better to IgG which was deficient in galactose. Six of the 16 rheumatoid factors from the same patients bound independently of the galactose content. Four of the 16 rheumatoid factors could not be absolutely grouped in this manner but seemed to demonstrate a preference for agalactosyl IgG. One rheumatoid factor bound better to fully galactosylated IgG. There was an association between enhanced binding to galactose-deficient IgG and monoreactivity and a very strong association between the functional affinity of the rheumatoid factors and the dependent binding.

A method based on PCR for the construction of cDNA libraries and probes from small amounts of tissue

A PCR-based method is described for the production of cDNA libraries and total cDNA probes from a few milligrams of tissue. Using a model system, we show how a PCR library and PCR probes can be used to identify genes expressed at different levels in two tissues. Small amounts of tissue derived from two plants, one infected with arabis mosaic virus and the other uninfected, were used to make a library and probes. This library and the probes were used to identify viral genes expressed only in the infected plant.

A novel form of pectinesterase in tomato

The pectinesterases in tomato pericarp were fractionated by cation exchange into four forms (A-D). Form A was the most abundant and C the second most abundant. Forms A-C were further purified by gel filtration, and antibodies were raised against A and C. Comparison of the different forms by dot blots and Western blots showed that although all three forms shared common immunological characteristics, there were also differences in their behaviour, indicative of structural differences. Form A had an N-terminal sequence identical to that published previously for the major pectinesterase in tomato fruit. In contrast, form C had a completely novel N-terminal sequence. Form A was absent from hypocotyls and roots. Forms B and C were present in comparable amounts in hypocotyls, while from C predominated in roots.