Managing Medications During "Sick Days" in Patients With Diabetes, Kidney, and Cardiovascular Conditions: A Theory-informed Approach to Intervention Design and Implementation

OBJECTIVES

Our aim in this work was to: 1) explore barriers and enablers to patient and health-care provider (HCP) behaviours related to sick-day medication guidance (SDMG), 2) identify theory-informed strategies to advise SDMG intervention design, and 3) obtain perspectives on an eHealth tool for this purpose.

METHODS

A qualitative descriptive study using qualitative conventional content analysis was undertaken. Interviews and focus groups were held with patients and HCPs from January 2021 to April 2022. Data were analyzed using the Behaviour Change Wheel and Theoretical Domains Framework to inform intervention design.

RESULTS

Forty-eight people (20 patients, 13 pharmacists, 12 family physicians, and 3 nurse practitioners) participated in this study. Three interventions were designed to address the identified barriers and enablers: 1) prescriptions provided by a community-based care provider, 2) pharmacists adding a label to at-risk medications, and 3) built-in prompts for prescribing and dispensing software. Most participants accepted the concept of an eHealth tool and identified pharmacists as the ideal point-of-care provider. Challenges for an eHealth tool were raised, including credibility, privacy of data, medical liability, clinician remuneration and workload impact, and equitable access to use of the tool.

CONCLUSIONS

Patients and HCPs endorsed non-technology and eHealth innovations as strategies to aid in the delivery of SDMG. These findings can guide the design of future theory-informed SDMG interventions.

Consensus Recommendations for Sick Day Medication Guidance for People With Diabetes, Kidney, or Cardiovascular Disease: A Modified Delphi Process

RATIONALE & OBJECTIVE

Sick day medication guidance (SDMG) involves withholding or adjusting specific medications in the setting of acute illnesses that could contribute to complications such as hypotension, acute kidney injury (AKI), or hypoglycemia. We sought to achieve consensus among clinical experts on recommendations for SDMG that could be studied in future intervention studies.

STUDY DESIGN

A modified Delphi process following guidelines for conducting and reporting Delphi studies.

SETTING & PARTICIPANTS

An international group of clinicians with expertise relevant to SDMG was recruited through purposive and snowball sampling. A scoping review of the literature was presented, followed by 3 sequential rounds of development, refinement, and voting on recommendations. Meetings were held virtually and structured to allow the participants to provide their input and rapidly prioritize and refine ideas.

OUTCOME

Opinions of participants were measured as the percentage who agreed with each recommendation, whereas consensus was defined as >75% agreement.

ANALYTICAL APPROACH

Quantitative data were summarized using counts and percentages. A qualitative content analysis was performed to capture the context of the discussion around recommendations and any additional considerations brought forward by participants.

RESULTS

The final panel included 26 clinician participants from 4 countries and 10 clinical disciplines. Participants reached a consensus on 42 specific recommendations: 5 regarding the signs and symptoms accompanying volume depletion that should trigger SDMG; 6 regarding signs that should prompt urgent contact with a health care provider (including a reduced level of consciousness, severe vomiting, low blood pressure, presence of ketones, tachycardia, and fever); and 14 related to scenarios and strategies for patient self-management (including frequent glucose monitoring, checking ketones, fluid intake, and consumption of food to prevent hypoglycemia). There was consensus that renin-angiotensin system inhibitors, diuretics, nonsteroidal anti-inflammatory drugs, sodium/glucose cotransporter 2 inhibitors, and metformin should be temporarily stopped. Participants recommended that insulin, sulfonylureas, and meglitinides be held only if blood glucose was low and that basal and bolus insulin be increased by 10%-20% if blood glucose was elevated. There was consensus on 6 recommendations related to the resumption of medications within 24-48 hours of the resolution of symptoms and the presence of normal patterns of eating and drinking.

LIMITATIONS

Participants were from high-income countries, predominantly Canada. Findings may not be generalizable to implementation in other settings.

CONCLUSIONS

A multidisciplinary panel of clinicians reached a consensus on recommendations for SDMG in the presence of signs and symptoms of volume depletion, as well as self-management strategies and medication instructions in this setting. These recommendations may inform the design of future trials of SDMG strategies.

High resolution TCSPC imaging of diffuse light with a one-dimensional SPAD array scanning system

We report a time-correlated single-photon counting (TCSPC) imaging system based on a line-scanning architecture. The system benefits from the high fill-factor, active area, and large dimension of an advanced CMOS single-photon avalanche diode (SPAD) array line-sensor. A two-dimensional image is constructed using a moving mirror to scan the line-sensor field-of-view (FOV) across the target, to enable the efficient acquisition of a two-dimensional 0.26 Mpixel TCSPC image. We demonstrate the capabilities of the system for TCSPC imaging and locating objects obscured in scattering media - specifically to locate a series of discrete point sources of light along an optical fibre submerged in a highly scattering solution. We demonstrate that by selectively imaging using early arriving photons which have undergone less scattering than later arriving photons, our TCSPC imaging system is able to locate the position of discrete point sources of light than a non-time-resolved imaging system.

Sick Day Medication Guidance for People With Diabetes, Kidney, or Cardiovascular Disease: A Systematic Scoping Review

Rationale & Objective

Sick day medication guidance has been promoted to prevent adverse events for people with chronic conditions. Our aim was to summarize the existing sick day medication guidance and the evidence base for the effectiveness of interventions for implementing this guidance.

Study Design

Scoping review of quantitative and qualitative studies.

Setting & Population

Sick day medication guidance for people with chronic conditions including diabetes mellitus, kidney diseases, and cardiovascular diseases.

Selection Criteria for Studies

A search of 6 bibliographic databases (Ovid MEDLINE, Ovid Embase, CINAHL, Scopus, Web of Science Core Collection, and Cochrane Library [via Wiley]) and a comprehensive gray literature search were completed in June 2021.

Data Extraction

Intervention and study characteristics were extracted using standardized tools.

Analytical Approach

Data were summarized descriptively, and our approach observed the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for scoping reviews.

Results

The literature search identified 2,308 documents, which were screened against the eligibility criteria, leading to 74 documents that were included. The majority of the identified documents (n = 55) were guidelines or educational resources. Of the 19 primary research studies identified, 10 studies described an intervention, with only 2 examining the effect of sick day medication guidance interventions within clinical care and no studies reporting beneficial effects on clinical outcomes. Most documents (n = 58) included guidance specific to patients with diabetes mellitus, with fewer including guidance for patients with chronic kidney disease (n = 9) or heart failure (n = 2).

Limitations

Risk of bias was not assessed.

Conclusions

Many resources promoting sick day medication guidance have been developed; however, there is very little empirical evidence for the effectiveness of current approaches in implementing sick day medication guidance into practice. Recommendations for the use of sick day medication guidance will require further research to develop consistent, understandable, and usable approaches for its implementation within self-management strategies as well as empirical studies to demonstrate the effectiveness of these interventions.

Diagnosing ventilator-associated pneumonia (VAP) in UK NHS ICUs: the perceived value and role of a novel optical technology

BACKGROUND

Diagnosing ventilator-associated pneumonia (VAP) in an intensive care unit (ICU) is a complex process. Our aim was to collect, evaluate and represent the information relating to current clinical practice for the diagnosis of VAP in UK NHS ICUs, and to explore the potential value and role of a novel diagnostic for VAP, which uses optical molecular alveoscopy to visualise the alveolar space.

METHODS

Qualitative study performing semi-structured interviews with clinical experts. Interviews were recorded, transcribed, and thematically analysed. A flow diagram of the VAP patient pathway was elicited and validated with the expert interviewees. Fourteen clinicians were interviewed from a range of UK NHS hospitals: 12 ICU consultants, 1 professor of respiratory medicine and 1 professor of critical care.

RESULTS

Five themes were identified, relating to [1] current practice for the diagnosis of VAP, [2] current clinical need in VAP diagnostics, [3] the potential value and role of the technology, [4] the barriers to adoption and [5] the evidence requirements for the technology, to help facilitate a successful adoption. These themes indicated that diagnosis of VAP is extremely difficult, as is the decision to stop antibiotic treatment. The analysis revealed that there is a clinical need for a diagnostic that provides an accurate and timely diagnosis of the causative pathogen, without the long delays associated with return of culture results, and which is not dangerous to the patient. It was determined that the technology would satisfy important aspects of this clinical need for diagnosing VAP (and pneumonia, more generally), but would require further evidence on safety and efficacy in the patient population to facilitate adoption.

CONCLUSIONS

Care pathway analysis performed in this study was deemed accurate and representative of current practice for diagnosing VAP in a UK ICU as determined by relevant clinical experts, and explored the value and role of a novel diagnostic, which uses optical technology, and could streamline the diagnostic pathway for VAP and other pneumonias.

Evaluation of intranasal nafamostat or camostat for SARS-CoV-2 chemoprophylaxis in Syrian golden hamsters

Successful development of a chemoprophylaxis against SARS-CoV-2 could provide a tool for infection prevention implementable alongside vaccination programmes. Camostat and nafamostat are serine protease inhibitors that inhibit SARS-CoV-2 viral entry in vitro but have not been characterised for chemoprophylaxis in animal models. Clinically, nafamostat is limited to intravenous delivery and while camostat is orally available, both drugs have extremely short plasma half-lives. This study sought to determine whether intranasal dosing at 5 mg/kg twice daily was able to prevent airborne transmission of SARS-CoV-2 from infected to uninfected Syrian golden hamsters. SARS-CoV-2 viral RNA was above the limits of quantification in both saline- and camostat-treated hamsters 5 days after cohabitation with a SARS-CoV-2 inoculated hamster. However, intranasal nafamostat-treated hamsters remained RNA negative for the full 7 days of cohabitation. Changes in body weight over the course of the experiment were supportive of a lack of clinical symptomology in nafamostat-treated but not saline- or camostat-treated animals. These data are strongly supportive of the utility of intranasally delivered nafamostat for prevention of SARS-CoV-2 infection and further studies are underway to confirm absence of pulmonary infection and pathological changes.

59 Should The ‘Normal’ And ‘Ideal’ Nipple Position in A Male Influence the Surgeon When Planning Severe Gynaecomastia Correction?

Background

The ideal nipple position of the male chest following gynecomastia surgery is well documented however with increased development of the chest muscles, the NAC placement can change, leading to the medial displacement of the nipple giving a poor aesthetic outcome. Therefore, we feel these measurements need to be applied to the patients build and take into consideration the patient's future fitness goals.

Method

We have analysed photographs of 3 groups of men: super- athletes, athletes and severe gynaecomastia. We assessed the proportions of the chest in relation to the NAC and the degree of ptosis.

Results

There is wide variation in the position of the nipple to the chest wall between each group with minor variation within each group. Based on this research we believe that surgeons should be circumspect when considering breast reduction with a Wise pattern in patients with severe gynaecomastia.

In patient with increased development of the pectoralis major muscles, the NAC placement can change, leading to medial displacement of the nipple and ptosis and poor aesthetic result.

Conclusions

We suggest a two-stage procedure, carried out on two separate occasions wound be more ideal than a single stage as this allows better long-term better positioning of the nipple.

Surgical margins for borderline and malignant phyllodes tumours

BACKGROUND

Phyllodes tumours represent less than 1% of all UK breast neoplasms. Histological features allow classification into benign, borderline or malignant, which has a significant impact on prognosis and recurrence. Currently, there is no consensus for the optimal surgical excision margin. This systematic review aims to provide a comparative summary of outcomes (local recurrence, metastasis and survival) for borderline and malignant phyllodes tumours resected with either ≥1cm or <1cm margins.

METHODS

MEDLINE and Embase were systematically searched (1990 to July 2019), in line with PRISMA guidelines. Study quality was assessed using the Newcastle-Ottawa scale.

RESULTS

Ten retrospective studies were included (Newcastle-Ottawa scale mean score: 5.6, range: 8-4). Nine reported local recurrence rates, four reported distant metastasis and four reported survival. Meta-analysis pooling demonstrated no statistically significant difference between <1cm and ≥1cm margins in terms of local recurrence rates (relative risk [RR] 1.43, 95% confidence interval [95% CI] 0.70 - 2.93; p=0.33, n=456), distant metastasis (RR 1.93, 95% CI 0.35 - 10.63; p=0.45, n=72) or mortality (RR 1.93, 95% CI 0.42 - 8.77; p=0.40, n=58) for borderline and malignant tumours. Additionally, two studies demonstrated no significant difference in local recurrence for borderline tumours excised with <0.1cm margins compared to ≥1cm.

CONCLUSION

Current evidence suggests that margins <1cm may provide adequate tumour excision. This could enable breast conservation in patients with smaller breast-to-tumour volume ratios, with improved cosmetic outcomes and patient satisfaction. A prospective, multi-institutional trial would be appropriate to further elucidate the safety of smaller margins.

The Suitability of Grounded Theory Research for Correctional Nursing

The tension between custody and caring is particular to correctional nursing practice, including issues such as the correctional priorities of safety and security that often dominate nursing practice. The evidence that should underlie correctional nursing practice is regrettably sparse. There are two reasons a grounded theory (GT) approach is paramount for building foundational knowledge to advance correctional nursing practice. First, the development of theories regarding correctional nursing practice will provide an in-depth understanding of this subspecialty of nursing and lead to further research endeavors. Second, correctional nursing practice is a process carried out in correctional institutions. The GT approach is "process oriented" and thus is appropriate for exploring the implementation of correctional nursing practice. Two GT approaches have evolved since first described by Glaser and Strauss. We contend that the approach offered by Strauss and Corbin may be more beneficial for studying how correctional nurses implement their practice.

pH sensing through a single optical fibre using SERS and CMOS SPAD line arrays

Full exploitation of fibre Raman probes has been limited by the obstruction of weak Raman signals by background fluorescence of the sample and the intrinsic Raman signal of the delivery fibre. Here we utilised functionalised gold nanoshells (NS) to take advantage of the surface-enhanced Raman spectroscopy (SERS) effect to enhance the pH responsive spectrum of 4-mercaptobenzoic acid (MBA). However, the fibre background is still dominant. Using the photon arrival time-resolving capability of a CMOS single-photon avalanche diode (SPAD) based line sensor, we recover the SERS spectrum without a fibre background in a 10 s measurement. In this manner, pH sensing through a multimode fibre at a low excitation power that is safe for future in vivo applications, with short acquisition times (10 or 60 s), is demonstrated. A measurement precision of ± 0.07 pH units is thus achieved.

Ballistic and snake photon imaging for locating optical endomicroscopy fibres

We demonstrate determination of the location of the distal-end of a fibre-optic device deep in tissue through the imaging of ballistic and snake photons using a time resolved single-photon detector array. The fibre was imaged with centimetre resolution, within clinically relevant settings and models. This technique can overcome the limitations imposed by tissue scattering in optically determining the in vivo location of fibre-optic medical instruments.

Time-resolved spectroscopy at 19,000 lines per second using a CMOS SPAD line array enables advanced biophotonics applications

A SPAD-based line sensor fabricated in 130 nm CMOS technology capable of acquiring time-resolved fluorescence spectra (TRFS) in 8.3 milliseconds is presented. To the best of our knowledge, this is the fastest time correlated single photon counting (TCSPC) TRFS acquisition reported to date. The line sensor is an upgrade to our prior work and incorporates: i) parallelized interface from sensor to surrounding circuitry enabling high line rate to the PC (19,000 lines/s) and ii) novel time-gating architecture where detected photons in the OFF region are rejected digitally after the output stage of the SPAD. The time-gating architecture was chosen to avoid electrical transients on the SPAD high voltage supplies when gating is achieved by excess bias modulation. The time-gate has an adjustable location and time window width allowing the user to focus on time-events of interest. On-chip integrated center-of-mass (CMM) calculations provide efficient acquisition of photon arrivals and direct lifetime estimation of fluorescence decays. Furthermore, any of the SPC, TCSPC and on-chip CMM modes can be used in conjunction with the time-gating. The higher readout rate and versatile architecture greatly empower the user and will allow widespread applications across many techniques and disciplines. Here we focused on 3 examples of TRFS and time-gated Raman spectroscopy: i) kinetics of chlorophyll A fluorescence from an intact leaf; ii) kinetics of a thrombin biosensor FRET probe from quenched to fluorescence states; iii) ex vivo mouse lung tissue autofluorescence TRFS; iv) time-gated Raman spectroscopy of toluene at 3056 cm^-1 peak. To the best of our knowledge, we detect spectrally for the first time the fast rise in fluorescence lifetime of chlorophyll A in a measurement over single fluorescent transient.

Follistatin is essential for normal postnatal development and function of mouse oviduct and uterus

Female mice lacking the follistatin gene but expressing a human follistatin-315 transgene (tghFST315) have reproductive abnormalities (reduced follicles, no corpora lutea and ovarian-uterine inflammation). We hypothesised that the absence of follistatin-288 causes the abnormal reproductive tract via both developmental abnormalities and abnormal ovarian activity. We characterised the morphology of oviducts and uteri in wild type (WT), tghFST315 and follistatin-knockout mice expressing human follistatin-288 (tghFST288). The oviducts and uteri were examined in postnatal Day-0 and adult mice (WT and tghFST315 only) using histology and immunohistochemistry. Adult WT and tghFST315 mice were ovariectomised and treated with vehicle, oestradiol-17β (100ng injection, dissection 24h later) or progesterone (1mg×three daily injections, dissection 24h later). No differences were observed in the oviducts or uteri at birth, but abnormalities developed by adulthood. Oviducts of tghFST315 mice failed to coil, the myometrium was disorganised, endometrial gland number was reduced and oviducts and uteri contained abundant leukocytes. After ovariectomy, tghFST315 mice had altered uterine cell proliferation, and inflammation was maintained and exacerbated by oestrogen. These studies show that follistatin is crucial to postnatal oviductal-uterine development and function. Further studies differentiating the role of ovarian versus oviductal-uterine follistatin in reproductive tract function at different developmental stages are warranted.

Endoscopic sensing of alveolar pH

Previously unobtainable measurements of alveolar pH were obtained using an endoscope-deployable optrode. The pH sensing was achieved using functionalized gold nanoshell sensors and surface enhanced Raman spectroscopy (SERS). The optrode consisted of an asymmetric dual-core optical fiber designed for spatially separating the optical pump delivery and signal collection, in order to circumvent the unwanted Raman signal generated within the fiber. Using this approach, we demonstrate a ~100-fold increase in SERS signal-to-fiber background ratio, and demonstrate multiple site pH sensing with a measurement accuracy of ± 0.07 pH units in the respiratory acini of an ex vivo ovine lung model. We also demonstrate that alveolar pH changes in response to ventilation.

Caring in Correctional Nursing: A Systematic Search and Narrative Synthesis

Registered nurses are the primary healthcare providers for offenders in correctional facilities. The way in which correctional nurses care for offenders can be difficult in this context. Following a systematic review and narrative synthesis of literature regarding how correctional nurses show caring for offenders three themes emerged: the struggle of custody and caring (conflicting ethical and philosophical ideologies, correctional priorities that override nursing priorities, safety and security), the need to be nonjudgmental (judgmental attitudes can impact care; focus on health not the crime), and the importance of boundaries. Implications for practice focus on recommendations to promote caring in correctional nursing; the outcome of which will potentially enhance quality of care for offenders and improve working environments for nurses.

Review of the cellular and biological principles of distraction osteogenesis: An in vivo bioreactor tissue engineering model

Distraction osteogenesis (DO) is a widely used technique in plastic and orthopaedic surgery. During the process, mechanical force is applied to fractured bone to enhance the regenerative processes and induce new bone formation. Although there is an abundance of literature on the clinical process of DO, there is a distinct lack of focus on the underlying biological principles governing this process. DO follows the basic premises of tissue engineering. The mechanical stress stimulates mesenchymal stem cell differentiation down an osteoblastic lineage on a matrix background. The aim of this review is to give an overview of the current knowledge of the molecular mechanism governing this process.

A prospective study of the use of botulinum toxin injections in the treatment of Raynaud's syndrome associated with scleroderma

Raynaud's syndrome contributes to the pain, paraesthesia, ulceration, and gangrene of scleroderma. Botulinum toxin has been shown to improve digital perfusion in patients with Raynaud's. This is the first study to objectively assess hand function following this treatment in patients with scleroderma. Twenty patients were treated with 100 units of botulinum toxin injected into the hand. An assessment of hand function and symptoms was performed prior to injection and then 8-12 weeks later. The outcomes assessed were change in pain, appearance, cold intolerance, pinch and power grip, ranges of movement, and Disabilities of the Arm, Shoulder and Hand (DASH) score. In total, 80% of patients reported an overall improvement in their symptoms, reduction in pain, and improved DASH score and 65% reported improvement in cold intolerance. Overall, 90% showed an improvement in pinch grip and 65% an improvement in power grip. Objective parameters were statistically significantly improved; however, subjective outcomes only showed a trend. We have found botulinum toxin to be an effective treatment for Raynaud's syndrome secondary to scleroderma.

Combined dysfunctions of immune cells predict nosocomial infection in critically ill patients

BACKGROUND

Nosocomial infection occurs commonly in intensive care units (ICUs). Although critical illness is associated with immune activation, the prevalence of nosocomial infections suggests concomitant immune suppression. This study examined the temporal occurrence of immune dysfunction across three immune cell types, and their relationship with the development of nosocomial infection.

METHODS

A prospective observational cohort study was undertaken in a teaching hospital general ICU. Critically ill patients were recruited and underwent serial examination of immune status, namely percentage regulatory T-cells (Tregs), monocyte deactivation (by expression) and neutrophil dysfunction (by CD88 expression). The occurrence of nosocomial infection was determined using pre-defined, objective criteria.

RESULTS

Ninety-six patients were recruited, of whom 95 had data available for analysis. Relative to healthy controls, percentage Tregs were elevated 6-10 days after admission, while monocyte HLA-DR and neutrophil CD88 showed broader depression across time points measured. Thirty-three patients (35%) developed nosocomial infection, and patients developing nosocomial infection showed significantly greater immune dysfunction by the measures used. Tregs and neutrophil dysfunction remained significantly predictive of infection in a Cox hazards model correcting for time effects and clinical confounders {hazard ratio (HR) 2.4 [95% confidence interval (CI) 1.1-5.4] and 6.9 (95% CI 1.6-30), respectively, P=0.001}. Cumulative immune dysfunction resulted in a progressive risk of infection, rising from no cases in patients with no dysfunction to 75% of patients with dysfunction of all three cell types (P=0.0004).

CONCLUSIONS

Dysfunctions of T-cells, monocytes, and neutrophils predict acquisition of nosocomial infection, and combine additively to stratify risk of nosocomial infection in the critically ill.

Imaging inflammation: molecular strategies to visualize key components of the inflammatory cascade, from initiation to resolution

Dysregulation of inflammation is central to the pathogenesis of innumerable human diseases. Understanding and tracking the critical events in inflammation are crucial for disease monitoring and pharmacological drug discovery and development. Recent progress in molecular imaging has provided novel insights into spatial associations, molecular events and temporal sequelae in the inflammatory process. While remaining a burgeoning field in pre-clinical research, increasing application in man affords researchers the opportunity to study disease pathogenesis in humans in situ thereby revolutionizing conventional understanding of pathophysiology and potential therapeutic targets. This review provides a description of commonly used molecular imaging modalities, including optical, radionuclide and magnetic resonance imaging, and details key advances and translational opportunities in imaging inflammation from initiation to resolution.

Pain in neonates during screening for retinopathy of prematurity using binocular indirect ophthalmoscopy and wide-field digital retinal imaging: a randomised comparison

OBJECTIVE

To compare the pain experienced by premature infants undergoing wide-field digital retinal imaging (WFDRI) and binocular indirect ophthalmoscopy (BIO) for retinopathy of prematurity (ROP) screening.

METHODS

Infants were recruited at Edinburgh Royal Infirmary Neonatal Unit, Edinburgh, UK. Eyes were examined by WFDRI and BIO with eyelid speculum by two experienced paediatric ophthalmologists in random order. A pain score (Premature Infant Pain Profile (PIPP)) for WFDRI and BIO was generated.

RESULTS

A total of 76 infants were recruited. The (mean, SD) PIPP score for WFDRI was 15.0, 2.1 and for BIO was 15.2, 2.4 (paired t test p=0.47). The authors observed that infants started crying with corresponding physiological changes as soon as the eyelid speculum was inserted and crying stopped on speculum removal.

CONCLUSION

WFDRI and BIO with eyelid speculum are similarly painful for infants. The authors speculate that the eyelid speculum rather than the examination method may contribute most to the pain experienced.

Stabilisation of Salmonella vaccine vectors by the induction of trehalose biosynthesis

The growth of an aroA mutant of Salmonella typhimurium (SL3261) in minimal medium containing 0.5 M NaCl resulted in the intracellular accumulation of 2.2 micromol trehalose/mg total protein. The vacuum drying of these bacteria in the presence of trehalose allowed the recovery of 35% of the viable cells that were present before drying. In contrast, bacteria cultured in control medium accumulated 0.4 micromol trehalose/mg total protein and only 5% of the viable cells were recovered after vacuum drying with trehalose. Similar results were obtained when S. typhimurium SL3261, expressing the vaccine antigen (F1-antigen) of Yersinia pestis, was cultured in minimal medium with or without 0.5 M NaCl and dried in the presence of trehalose. Although these results indicate the potential for trehalose stabilisation of vaccine strains of S. typhimiurium, growth in minimal medium containing 0.5 M NaCl resulted in the loss of invasion competence of the bacteria.

Liver tryptophan pyrrolase. A major determinant of the lower brain 5-hydroxytryptamine concentration in alcohol-preferring C57BL mice

The lower brain 5-hydroxytryptamine concentration in alcohol-preferring C57BL, compared with -non-preferring CBA, mice is caused by a decrease in circulating tryptophan availability to the brain secondarily to a higher liver tryptophan pyrrolase activity associated with a higher circulating corticosterone concentration. Activity or expression of liver tryptophan pyrrolase and/or their induction by glucocorticoids may be important biological determinants of predisposition to alcohol consumption.

The effects of chronic lead treatment and hypertension on the severity of cardiac arrhythmias induced by coronary artery occlusion or by noradrenaline in anaesthetised rats

The aim of this study was to investigate whether chronic (3 months) lead (250 or 1000 ppm), administered as lead acetate in the drinking water, commencing either after weaning (in normotensive or spontaneously hypertensive male rats) or from conception (normotensive rats only) altered the susceptibility of the heart to arrhythmias induced either by coronary artery occlusion or by noradrenaline. Treatment with lead alone had no marked effect on the arrhythmias elicited by either method. Spontaneously hypertensive rats treated with either dose of lead exhibited more ectopic beats following coronary artery occlusion than normotensive rats but not more than those observed in control spontaneously hypertensive rats. An enhanced arrhythmogenic effect of noradrenaline was observed only in hypertensive rats administered 250 ppm lead. Both doses of lead accelerated the development of high blood pressure and in normotensive rats the higher dose also resulted in an elevated pressure. Following administration of lead, blood lead concentrations were elevated to 0.96 and 2.11 mumol l-1 after 250 and 1000 ppm, respectively. Accumulation of lead in heart and bone was also observed. We conclude that chronic exposure to these concentrations of lead, when combined with high blood pressure, slightly enhances the susceptibility of the heart to arrhythmias induced by myocardial ischaemia.