Clinical research stakeholders' experiences of clinical research during COVID-19: a qualitative study

BACKGROUND

The COVID-19 pandemic created a complex high-risk clinical research environment with clinical research activities significantly impacted. Clinical research stakeholders adapted rapidly to new clinical practices; PPE, infection control policies, all while engaging with a more unwell patient demographic. The aim of this study is to explore the experiences of conducting clinical research during COVID-19 with clinical research stakeholders.

METHODS

This qualitative study of semi-structured interviews conducted with clinical research stakeholders in an acute Hospital setting across a variety of disciplines; Consultant Geriatrician, Clinical Research Nurse, Occupational Therapy, Physiotherapy. Interviews were fully transcribed prior to reflexive thematic analysis. NVivo software was used to support data management and analysis.

RESULTS

Three main themes were produced; (1) The challenging COVID-19 clinical research landscape, (2) COVID-19 clinical research communication barriers, and (3) Adaptations and learnings from clinical research during COVID-19.

CONCLUSIONS

This study explored the experiences of conducting clinical research during COVID-19 with clinical research stakeholders examining challenges faced and adaptations required. The findings inform, equip and support clinical research stakeholders in the event of future adverse public health events.

A blood biomarker and clinical correlation cohort study protocol to diagnose sports-related concussion and monitor recovery in elite rugby

Introduction

In professional rugby, sports-related concussion (SRC) remains the most frequent time loss injury. Therefore, accurately diagnosing SRC and monitoring player recovery, through a multi-modal assessment process, is critical to SRC management. In this protocol study, we aim to assess SRC over multiple time points post-injury to determine the value of multi-modal assessments to monitor player recovery. This is of significance to minimise premature return-to-play and, ultimately, to reduce the long-term effects associated with SRC. The study will also establish the logistics of implementing such a study in a professional setting to monitor a player's SRC recovery.

Methods and analysis

All players from the participating professional rugby club within the Irish Rugby Football Union are invited to participate in the current study. Player assessment includes head injury assessment (HIA), neuropsychometric assessment (ImPACT), targeted biomarker analysis and untargeted biomarker analysis. Baseline HIA, ImPACT, and blood draws are performed prior to the start of playing season. During the baseline tests, player's complete consent forms and an SRC history questionnaire. Subsequently, any participant that enters the HIA process over the playing season due to a suspected SRC will be clinically assessed (HIA and ImPACT) and their blood will be drawn within 3 days of injury, 6 days post-injury, and 13 days post-injury.

Ethics and dissemination

Ethical approval was attained from the Science and Engineering Research Ethics Committee, University of Limerick (Approval Code: 2018_06_11_S&E). On completion of the study, further manuscripts will be published to present the results of the tests and their ability to measure player recovery from SRC.

Trial registration number

NCT04485494.

'Everything was just getting worse and worse': deteriorating job quality as a driver of doctor emigration from Ireland

BACKGROUND

Medicine is a high-status, high-skill occupation which has traditionally provided access to good quality jobs and relatively high salaries. In Ireland, historic underfunding combined with austerity-related cutbacks has negatively impacted job quality to the extent that hospital medical jobs have begun to resemble extreme jobs. Extreme jobs combine components of a good quality job-high pay, high job control, challenging demands, with those of a low-quality job-long working hours, heavy workloads. Deteriorating job quality and the normalisation of extreme working is driving doctor emigration from Ireland and deterring return.

METHODS

Semi-structured qualitative interviews were conducted with 40 Irish emigrant doctors in Australia who had emigrated from Ireland since 2008. Interviews were held in July-August 2018.

RESULTS

Respondents reflected on their experiences of working in the Irish health system, describing hospital workplaces that were understaffed, overstretched and within which extreme working had become normalised, particularly in relation to long working hours, fast working pace, doing more with less and fighting a climate of negativity. Drawing on Hirschman's work on exit, voice and loyalty (1970), the authors consider doctor emigration as exit and present respondent experiences of voice prior to emigration. Only 14/40 respondent emigrant doctors intend to return to work in Ireland.

DISCUSSION

The deterioration in medical job quality and the normalisation of extreme working is a key driver of doctor emigration from Ireland, and deterring return. Irish trained hospital doctors emigrate to access good quality jobs in Australia and are increasingly likely to remain abroad once they have secured them. To improve doctor retention, health systems and employers must mitigate a gainst the emergence of extreme work in healthcare. Employee voice (about working conditions, about patient safety, etc.) should be encouraged and used to inform health system improvement and to mitigate exit.

Making sense of bodily sensations: Do shared cancer narratives influence symptom appraisal?

Though new or altered bodily sensations are a common occurrence they rarely transition to biomedically defined symptoms. When they do, sensations are subject to an appraisal process that can culminate in help-seeking. The transition has particular relevance for cancer diagnoses. Studies of 'symptom appraisal' in cancer patients typically conclude that failure to regard sensations as serious or 'symptom misattribution' results in lengthier help-seeking intervals. Though multiple influences on appraisal processes are acknowledged, including the socio-cultural context, detailed description and analyses of how socio-cultural factors shape appraisal is lacking. In this paper we explore one substantial component of the sociocultural context, namely, publicly recognised shared cancer narratives, and their impact on appraisal. We undertook a secondary analysis of 24 interviews with Scottish colorectal cancer patients originally completed in 2006-2007. Our analysis showed that fear, death and severity dominated cancer narratives and were frequently restated throughout interviews. Yet, early bodily changes were often mild and vague, were commonly experienced in the context of 'feeling well' and failed to match preconceived ideas of what cancer 'feels like'. Moreover, few perceived themselves to be 'at risk' of cancer and diagnoses were characterised as 'shocking' events. Participants engaged in self-monitoring strategies and severe or painful changes prompted help-seeking. Far from misattributing symptoms, responses to bodily changes were sensible and measured; responses are particularly apt in relation to current policy rhetoric, which urges measured use of services. Our findings have resonance across healthcare settings as patients are required to negotiate a narrow and challenging space when making decisions to seek help. There is a pressing need for a more realistic approach to symptom appraisal in order to reduce help-seeking intervals. Future awareness campaigns should emphasise the importance of vague/minor bodily changes although this will necessitate discussions with health professionals on referral thresholds to achieve earlier detection.

A Single-arm, Practical Application Assessment of User Experience and Peristomal Skin Condition Among Persons With an Ileostomy Using a New Barrier Seal With Assisted Flow

Peristomal skin complications are a common problem for persons with an ileostomy.

PURPOSE

The purpose of this pilot study was to solicit user feedback and perform an initial assessment of the performance of a new barrier seal designed to decrease the risk of chemical-induced dermatitis.

METHODS

Seven (7) potential participants who were at least 18 years of age, >6 months post surgery, with an end or loop ileostomy and unbroken peristomal skin, and who were capable of changing their appliance themselves or had the availability of care assistance were identified and recruited by the stoma care nurse at the University Hospital, Limerick, Ireland. At the initial visit and after 1 and 2 weeks, participants were asked to rate device comfort, security, and handling; skin condition was assessed by the research nurse using the Ostomy Skin Tool. Descriptive statistics were used to tabulate the results.

RESULTS

Five (5) participants completed the study. Discoloration, erosion, and tissue overgrowth scores improved in 3 of 5 patients, and the mean Ostomy Skin Tool score decreased from 5.4 ± 2.19 at the initial assessment to 4 ± 1.87 at the week 2 visit. Comfort, handling, and security ratings increased from a median of 8 at the beginning of the study to 10 at week 2.

CONCLUSION

Initial patient feedback regarding the new product was positive, and skin assessment results suggest the new seal may help improve peristomal skin condition. Larger studies with longer patient follow-up are needed to confirm the results of this pilot evaluation.

The evolution of methods for urinary steroid metabolomics in clinical investigations particularly in childhood

The metabolites of cortisol, and the intermediates in the pathways from cholesterol to cortisol and the adrenal sex steroids can be analysed in a single separation of steroids by gas chromatography (GC) coupled to MS to give a urinary steroid profile (USP). Steroids individually and in profile are now commonly measured in plasma by liquid chromatography (LC) coupled with MS/MS. The steroid conjugates in urine can be determined after hydrolysis and derivative formation and for the first time without hydrolysis using GC-MS, GC-MS/MS and liquid chromatography with mass spectrometry (LC-MS/MS). The evolution of the technology, practicalities and clinical applications are examined in this review. The patterns and quantities of steroids changes through childhood. Information can be obtained on production rates, from which children with steroid excess and deficiency states can be recognised when presenting with obesity, adrenarche, adrenal suppression, hypertension, adrenal tumours, intersex condition and early puberty, as examples. Genetic defects in steroid production and action can be detected by abnormalities from the GC-MS of steroids in urine. New mechanisms of steroid synthesis and metabolism have been recognised through steroid profiling. GC with tandem mass spectrometry (GC-MS/MS) has been used for the tentative identification of unknown steroids in urine from newborn infants with congenital adrenal hyperplasia. Suggestions are made as to areas for future research and for future applications of steroid profiling. As routine hospital laboratories become more familiar with the problems of chromatographic and MS analysis they can consider steroid profiling in their test repertoire although with LC-MS/MS of urinary steroids this is unlikely to become a routine test because of the availability, cost and purity of the internal standards and the complexity of data interpretation. Steroid profiling with quantitative analysis by mass spectrometry (MS) after chromatography now provides the most versatile of tests of adrenal function in childhood.

A Direct Oral Anticoagulant as a Cost Effective Alternative to Warfarin for Treatment of Provoked Venous Thrombosis

In Ireland, Warfarin is the primary anticoagulant prescribed in the secondary prevention of provoked DVT. We completed a comprehensive cost analysis of a trial group of 24 patients treated with Rivaroxaban (between November 2013 and December 2014), versus a control group treated with Warfarin (between January 2008 and November 2013). The groups were matched for gender (3/7 M/F ratio), DVT type (5 proximal, 19 distal DVTs), provoking factor (20 traumatic, 4 atraumatc), and age. We calculated the cost for each group based on drug administration and clinic costs (labour, sample analysis, and additional costs). Warfarin patients attended clinic 14.58 times; Rivaroxaban patients attended 2.92 times. Overall, the cost per patient on Rivaroxaban is €273.30 versus €260.68 with warfarin. This excludes patient costs which would further increase cost of Warfarin therapy.

Predictors of therapy resistant asthma: outcome of a systematic evaluation protocol

BACKGROUND

It has been suggested that asthmatic subjects with persisting symptoms despite adequate maintenance therapy should be systematically evaluated to identify factors contributing to poor control. The aims of this study were to examine the prevalence of these factors in a cohort of sequentially referred poorly controlled asthmatics, and to determine if any factor or combination of factors predicted true therapy resistant asthma (TRA).

METHODS

Patients were evaluated using a systematic evaluation protocol including induced sputum analysis, psychiatric assessment, ear, nose and throat examination, pulmonary function testing, high resolution CT scan of the thorax, and 24 hour dual probe ambulatory oesophageal pH monitoring; any identified provoking factor was treated. Asthma was managed according to BTS guidelines.

RESULTS

Of 73 subjects who completed the assessment, 39 responded to intervention and 34 had TRA. Subjects with TRA had a greater period of instability, a higher dose of inhaled steroids at referral, more rescue steroid use, and a lower best percentage forced expiratory volume in 1 second (FEV(1)%). Oesophageal reflux, upper airway disease, and psychiatric morbidity were common (57%, 95%, 49%, respectively) but were not more prevalent in either group. Using multivariate logistic regression analysis, inhaled steroid dose >2000 micro g BDP, previous assessment by a respiratory specialist, and initial FEV(1)% of <70% at referral predicted a final diagnosis of TRA.

CONCLUSIONS

In poorly controlled asthmatics there is a high prevalence of co-morbidity, identified by detailed systematic assessment, but no difference in prevalence between those who respond to intervention and those with TRA. Targeted treatment of identified co-morbidities has minimal impact on asthma related quality of life in those with therapy resistant disease.

The design and synthesis of potent inhibitors of hepatitis C virus NS3-4A proteinase

Hepatitis C virus (HCV) is the cause of the majority of transfusion-associated hepatitis and a significant proportion of community-acquired hepatitis worldwide. Infection by HCV frequently leads to persistent infections that result in a range of clinical conditions including an asymptomatic carrier state, severe chronic active hepatitis, cirrhosis and, in some cases, hepatocellular carcinoma. The HCV genome consists of a single-stranded, positive sense RNA containing an open reading frame of approximately 9060 nucleotides. This is translated into a single polyprotein of approximately 3020 amino acids (C-E1-E2-p7-NS2-NS3-NS4A-NS4B-NS5A-NS5B), which in turn is processed by a series of host and viral proteinases into at least 10 cleavage products. The N-terminal portion of the NS3 protein encodes a serine proteinase that is responsible for the cleavage at the NS3-4A, NS4A-4B, NS4B-5A and NS5A-5B junctions. The 54 amino acid NS4A protein is a cofactor that binds to the NS3 protein and enhances its proteolytic activity. This report describes the expression of a recombinant NS3-4A proteinase fusion protein in Escherichia coli and the in vitro characterization of the enzyme activity using synthetic peptide substrates. It then demonstrates how these results were employed to guide the design of potent inhibitors of this enzyme.

Mutation screening and isoform prevalence of the follicle stimulating hormone receptor gene in women with premature ovarian failure, resistant ovary syndrome and polycystic ovary syndrome

OBJECTIVE

To determine whether mutations in the FSH receptor gene are associated with premature ovarian failure (POF) or resistant ovary syndrome (ROS) in women in the UK. To determine whether an allelic variant of the FSH receptor gene affects fertility parameters in women with polycystic ovary syndrome (PCOS).

DESIGN

A mutation screen using DNA from women with POF and ROS. Restriction digest of amplified DNA from women with POF, ROS, PCOS and controls to determine allelic variant status. Fertility parameters were compared between allelic variant subgroups of women with PCOS.

PATIENTS

The study population comprised 49 women with POF, 5 with ROS, 93 with PCOS and 51 controls.

MEASUREMENTS

In women with PCOS, fertility and menstrual status was recorded and serum FSH and ovarian volume were measured.

RESULTS

No mutation of the FSH receptor gene was found in women with POF or ROS. The allelic variant Thr307/Ser680 was found to be similarly prevalent in all study groups. The Thr307/Ser680 variant was found to have no phenotype in terms of fertility parameters in women with PCOS.

CONCLUSIONS

Mutations of the FSH receptor gene are rare in women with premature ovarian failure or resistant ovary syndrome in the UK. Polymorphisms of the FSH receptor gene do not appear to have pathophysiological significance with regard to ovarian function.

Abnormal development of biceps brachii phasic stretch reflex and persistence of short latency heteronymous reflexes from biceps to triceps brachii in spastic cerebral palsy

Co-contraction of antagonist muscles is characteristic of spasticity arising from perinatal brain damage but not in spasticity occurring after brain damage in adulthood. Such co-contraction is a normal feature of early post-natal motor development. Heteronymous, monosynaptic Group Ia projections from biceps brachii to both the antagonist triceps brachii and to other synergist and non-synergist muscles of the upper limb occur in the newborn baby and become restricted during the first 4 years to motor neurons of primarily synergistic muscles. Longitudinal and cross-sectional studies have been performed to test the hypothesis that inappropriate heteronymous excitatory projections persist in children with perinatal brain damage who develop spasticity. Subjects with spasticity, from brain damage acquired in adulthood were also studied to determine if these projections simply become unmasked as part of spasticity, independent of the age of occurrence of the brain damage. Twenty-nine healthy newborn babies and 29 at high risk for cerebral palsy, 12 of whom developed spastic quadriparesis, were studied longitudinally for 4 years. Thirty-eight subjects, aged 8-30 years, with spasticity of perinatal origin (11 hemiplegic, 11 quadriplegic, 16 with Rett syndrome) and 11 subjects with stroke in adulthood and spastic hemiplegia were also studied. The results were compared with those obtained in 372 normal subjects aged from birth to 55 years. Small taps were delivered to the tendon of biceps brachii using an electromechanical tapper. Surface EMG was recorded from biceps and triceps brachii, pectoralis major and deltoid. In the longitudinal study, those developing spastic quadriparesis showed persistent low thresholds for the homonymous phasic stretch reflex, which had abnormally short onset latencies. There was persistence of short onset heteronymous excitatory responses in triceps brachii, while a normal pattern of restriction of heteronymous responses to pectoralis major and deltoid occurred. The same pattern was observed in older subject groups with spasticity of perinatal origin. In adults with hemiplegia following stroke the threshold of the homonymous phasic stretch reflex was low, but it had a normal onset latency. There was no evidence of abnormal heteronymous excitatory responses. In conclusion, exaggerated excitatory responses to primary muscle afferent input were observed in the homonymous (biceps brachii) and antagonist (triceps brachii) motor neurons in subjects with spasticity arising from perinatal brain damage. They are likely to play an important role in the predominant co-contraction of agonist/antagonist muscles during voluntary movement observed in subjects with spastic cerebral palsy.

Rn Delegation: the New Jersey Task Force recommendations

Because licensure and delegation clauses are determined state by state, all statewide home care associations need to begin a dialogue concerning delegation and how it impacts the nurse's practice and the way agencies deliver care in the community. State organizations need to communicate with each other and share concerns and experiences with other state home care organizations. Nursing boards, nursing and home health aide associations, advocates for long-term care patients, and the older population also need to be involved in the discussion. This open dialogue between many different organizations concerning delegation will ensure that patients receive safe, quality care that is also cost effective.

Adrenal function and high dose inhaled corticosteroids for asthma

OBJECTIVE

To investigate effects on adrenal function of fluticasone, a recently released inhaled steroid preparation with lower systemic bioavailability than beclomethasone dipropionate.

METHODS

34 children on high doses (400-909 micrograms/m2/d) of inhaled beclomethasone dipropionate or budesonide were recruited into a double blind, crossover study investigating the effects on adrenal function of beclomethasone and fluticasone propionate, given using a standard spacer (Volumatic). The 24 hour excretion rates of total cortisol and cortisol metabolites were determined at baseline (after a two week run in), after six weeks treatment with an equal dose of beclomethasone, and after six weeks of treatment with half the dose of fluticasone, both given through a spacer device.

RESULTS

The comparison of effects between fluticasone and beclomethasone during treatment periods, although favouring fluticasone in all measured variables, reached significance only after correction for urinary creatinine excretion (tetrahydrocortisol and 5 alpha-tetrahydrocortisol geometric means: 424 v 341 micrograms/m2/d). The baseline data showed adrenal suppression in the children taking beclomethasone (total cortisol geometric means: 975 v 1542 micrograms/d) and a dose related suppression in the children taking budesonide. Suppressed adrenal function in the children who were taking beclomethasone at baseline subsequently improved with fluticasone and beclomethasone during treatment periods.

CONCLUSIONS

Fluticasone is less likely to suppress adrenal function than beclomethasone at therapeutically equivalent doses. The baseline data also support the claim that spacer devices should be used for the administration of high doses of inhaled topical steroids.

Identification of transglutaminase substrates in HT29 colon cancer cells: use of 5-(biotinamido)pentylamine as a transglutaminase-specific probe

A biotinamine probe, 5-(biotinamido)pentylamine, was used for biotin-labeling of proteins in HT29 colon cancer cell extracts by endogenous transglutaminase activity. The biotin-labeled protein substrates were isolated and recovered by avidin-affinity chromatography. The proteins were separated using SDS-polyacrylamide gel electrophoresis, electroblotted onto a polyvinylidene difluoride membrane, visualized using Coomassie blue, cut out, and sequenced. Amino acid sequence data identified human fructose-1,6-bisphosphate aldolase A, an intracellular protein, as a substrate for cellular transglutaminase.

Localization of cellular transglutaminase on the extracellular matrix after wounding: characteristics of the matrix bound enzyme

Extending our previous observation that tissue transglutaminase (TGase) binds to extracellular matrix (ECM) fibronectin, we report here that endogenous tissue TGase is localized on the adjacent ECM after puncture wounding embryonic human lung fibroblasts (WI-38). The bound TGase persisted at the wound site for many hours, demonstrated by immunofluorescence and by catalytic activity using an overlay assay. The binding characteristics of TGase with ECM were studied further by the addition of exogenous TGase to cell monolayers and monitoring by immunofluorescence or overlay catalytic activity assays. Binding occurred equally well at 4 degrees C or 37 degrees C. Prior incubation of exogenous TGase with guanosine 5'-triphosphate (GTP), guanosine 5'-diphosphate (GDP), or adenosine triphosphate (ATP) had little effect on the amount bound to matrix, but prior treatment with calcium, magnesium, strontium, or manganese ions enhanced binding 2- to 3-fold. The Ca(++)-dependent change was a concentration-dependent effect on soluble exogenous TGase, rather than an effect on ECM. Immunofluorescent techniques showed that binding of exogenous TGase to ECM was prevented by prior mixing with fibronectin or collagen, but not with several other ECM components, including laminin, elastin, chondroitin sulfate, heparan sulfate, and hyaluronic acid. ECM-bound TGase was released by 2 M potassium thiocyanate (KSCN) treatment but was not released by treatment with a variety of amino acids, salts, reducing agents, glycerol, or other chaotropic agents.

Differential expression of transglutaminase in human erythroleukemia cells in response to retinoic acid

Two human erythroleukemia cell lines, HEL and K562, express transglutaminase activity. The enzyme was identified as a tissue transglutaminase following chromatographic purification. All-trans-retinoic acid (10 microM) stimulated differentiation in HEL cells as judged by a 4-fold increase in hemoglobin content and a reduction in cell proliferation. The transglutaminase activity increased 9-fold. This increase in transglutaminase was the result of a pretranslational regulation of the gene as revealed by Northern blot analysis of mRNA. These changes were not a result of cell apoptosis, since parallel DNA degradation catalyzed by a Ca2(+)-dependent endonuclease could not be demonstrated. The K562 cells, in contrast, showed no transglutaminase induction following exposure to retinoic acid and displayed no changes in maturation markers or cell growth.

Adrenal function in asthma

A dose dependent suppression of daily cortisol excretion was shown in 25 children with asthma being treated with beclomethasone dipropionate. Cortisol metabolites tended to occur below the normal range when doses of beclomethasone of more than 400 micrograms/m2/day were given. Androgen excretion below the normal range was apparent in asthmatic children aged 8-13 years regardless of whether they were receiving inhaled steroids. This may be the reason for growth delay often seen in asthmatic children. These side effects of beclomethasone are not enough reason to discourage its prescription for the treatment of asthma, but endocrine assessment is desirable when the dose exceeds 400 micrograms/m2/day.

Colorimetric assay for cellular transglutaminase

A colorimetric assay for cellular transglutaminase using 5-(biotinamido)pentylamine and polyvinylidine difluoride membranes for crude cellular preparations and purified enzyme has been developed. The biotinpentylamine substrate was incorporated into N,N-dimethylcasein by transglutaminase, the biotinylated products were adsorbed onto the membrane disks and conjugated with streptavidin-beta-galactosidase, and the absorbance resulting from the formation of p-nitrophenol from hydrolysis of p-nitrophenyl-beta-D-galactopyranoside was measured at 405 nm. The validity of the assay was established by showing a good correlation, gamma = 0.922, between the colorimetric procedure and the commonly used radiometric filter paper method for the enzyme. The procedure offers a rapid, sensitive, and nonisotopic method for the estimation of cellular transglutaminase activity in as low as 20 ng of purified guinea pig liver transglutaminase and 10 micrograms of crude fibroblast cytosol protein.

Cellular transglutaminase has affinity for extracellular matrix

Cellular transglutaminase (TGase) was demonstrated as an intracellular enzyme by immunofluorescence in WI-38 cells. Following cell membrane perturbation by Triton X-100 treatment, TGase was bound to the extracellular matrix and was found to coexist with fibronectin as visualized by immunofluorescence microscopy. The binding of TGase to the cell matrix was blocked by anti-fibronectin antibody. Exogenous sources of soluble TGase were transferred to the extracellular matrix of an untreated or methanol fixed cell. The experimental data indicated that "particulate bound" TGase is a consequence of soluble TGase binding to the extracellular matrix following cell rupture.

Induction of cellular transglutaminase biosynthesis by sodium butyrate

Cellular transglutaminase activity was induced in simian virus-transformed human embryonic lung fibroblasts (WI-38 VA13A) by sodium butyrate. The level of enzyme activity approached a maximum by 6 days; 9-11-fold higher in the presence of sodium butyrate (1 mM) than in its absence. The observed increases in cellular transglutaminase activity could be entirely accounted for by equivalent increases in the levels of enzyme protein measured by inhibition enzyme-linked immunosorbent assay. Sodium butyrate also increased the rate of enzyme synthesis, but had no effect on the rate of cellular transglutaminase degradation. The increase in the rate of enzyme synthesis was matched by an increased level of translatable transglutaminase mRNA as measured in a cell-free translation system. Our results suggest that sodium butyrate regulates cellular transglutaminase at the pretranslational level.

Variable transglutaminase activity in human diploid fibroblasts during in vitro senescence

The specific activity of transglutaminase (TGase) was followed in human diploid fibroblasts (HDF) as a function of in vitro age. It was determined that at least 90% of the TGase activity was found in a soluble fraction at all in vitro ages; but the activity was variable with age. It was high in cells that had completed less than 50% of their lifespan (%LSC), declined to a minimum between 60 and 85% LSC, and again became elevated at more than 90% LSC. These age related variations in TGase activity could not be attributed to cellular growth characteristics, enzyme amount, or clonal selection processes. It is postulated that the variable TGase activity observed during in vitro senescence of HDF may reflect a change in affinity of the enzyme for a particular molecule; possibly fibronectin.

A monoclonal antibody to cellular transglutaminase

A cellular enzyme-linked immunosorbent assay was developed for estimating cellular transglutaminase in situ using a monoclonal antibody produced to tissue transglutaminase. The minimum level of detection of TGase was 2-5 ng. The enzyme was present in greater amounts in WI-38 and IMR90 cells than in their simian virus-transformed counterparts. The levels of TGase in the virus-transformed cells increased significantly when the cells were grown in the presence of sodium butyrate to induce enzyme activity. Staining of confluent WI-38 cells by indirect immunofluorescence using the monoclonal antibody showed microscopic fibers suggesting that the enzyme may be associated with detergent-insoluble components.

Effects of methyldopa metabolites on amine transmitters and adrenergic receptors in rat brain

Studies of catecholamine concentrations in defined nuclei from the anterior hypothalamic-preoptic regions and the medulla oblongata, known to contribute to cardiovascular control, were measured following acute or chronic methyldopa administration. These studies indicated that methyldopa was enzymatically converted to methyldopamine and methylnorepinephrine, and in some areas to methylepinephrine which replaced endogenous epinephrine. The predominant metabolite was methylnorepinephrine, which accumulated in concentrations higher than endogenous norepinephrine levels. (-)Methylnorepinephrine was found to be 6 times more potent and 75 times more selective for alpha 2-adrenergic receptors than (-) norepinephrine, and it is suggested that this alpha 2-adrenergic receptor action, particularly in the nucleus tractus solitarius, contributes to a major part of the antihypertensive effect of methyldopa.

Enhanced transglutaminase activity in transformed human lung fibroblast cells after exposure to sodium butyrate

The low level of transglutaminase activity in virus-transformed human embryonic lung fibroblasts (WI-38 VA13A) increased markedly when cells were exposed to sodium butyrate. The effect of sodium butyrate was time- and concentration-dependent and fully reversible. Transformed cells exposed for 5 days to 1 mM sodium butyrate had fewer cells, showed an 8-10 fold higher transglutaminase activity, and stained more abundantly for transglutaminase and pericellular fibronectin than control cells when examined by indirect immunofluorescence. Non-transformed cells (WI-38) showed only a 2-4-fold increase in transglutaminase activity when treated in a similar manner. Studies with metabolic inhibitors revealed the increase in activity was the result of synthesis of new protein. Kinetic studies showed the affinity of putrescine for the enzyme was essentially unchanged but the number of active sites increased 9-fold following exposure to sodium butyrate. Enhanced transglutaminase activity returned to control levels within 7 days after subculture and sodium butyrate removal. These findings suggest that sodium butyrate offers a potential model system to understand better the role of transglutaminase in cells in culture; particularly growth control in transformed cells.

The definitive identification of the lignans trans-2,3-bis(3-hydroxybenzyl)-gamma-butyrolactone and 2,3-bis(3-hydroxybenzyl)butane-1,4-diol in human and animal urine

The definitive identification of the first lignans to be found in humans and animals is described. Gas chromatography--mass spectrometry, n.m.r. spectroscopy, i.r. spectroscopy and chemical techniques were employed to establish the structures of two lignans as trans-2,3-bis(3-hydroxybenzyl)-gamma-butyrolactone and 2,3-bis(3-hydroxybenzyl)butane-1,4-diol. Both compounds are essetially racemic. Evidence was also found for several methoxy analogues of these lignans in the vervet monkey.

Increase in proliferative markers after inhibition of transglutaminase

Cystamine inhibited transglutaminase activity (R-glutaminyl-peptide:amine gamma-glutamyltransferase, EC 2.3.2.13) of proliferating WI-38 cells in a dose-dependent manner over the concentration range 0.005-0.25 mM when added to the culture medium. The epsilon-(gamma-glutamyl)lysine content in the cells was decreased and several proliferation markers were enhanced. "Non-mitotic" cells were stimulated by cystamine (about 25% of that observed with 10% fetal bovine serum) to undergo DNA synthesis with subsequent increases in nuclei number. Numerous other disulfides, thiols, and amines were ineffective when added to culture medium. The findings are supportive of the concept that growth control involves a relationship between isopeptide crosslinks and proliferation.

Transglutaminase activity in normal and transformed cells

Transglutaminase activity was determined in normal and transformed paired cell systems. Reduced enzyme activity was found in virus-transformed human and hamster cells and in chemically transformed mouse cells relative to normal counterparts. Most of the enzyme activity was localized in the particulate fraction sedimenting at 105,000 X g. Enzyme activity was highest when normal cell populations were in an essentially nonmitotic state. Protein capable of incorporating putrescine was present in normal and transformed human cells, although the rate of incorporation was lower in the latter. The putrescine acceptor in the normal cell paralleled enzyme activity and enzyme distribution. Trypsin (5 microng/ml) treatment of the normal cell resulted in a 3-fold increase in enzyme activity, which occurred independently of protein synthesis.

Amino acid and hexose transport of normal and simian virus 40-transformed human cells

Studies on amino acid and hexose transport were performed on human WI-38 cells and WI-38 SV40-transformed cells (VA13A and VA13-2RA). Depending upon cell line or conditions, either no difference or a relative decrease in initial uptake by transformed cells was found. Under similar growth conditions, transformed hamster cells (PyBHK-21/C13) had increased uptake, compared with the normal hamster cells (BHK-21/C13). The normal and transformed human cells were also similar in sialic acid content and agglutinated when treated with concanavalin A.