A Brief Cognitive Analytic Therapy-Informed Approach for Young People That Have Self-Injured (CATCH-Y): A Case Series

BACKGROUND

Non-suicidal self-injury (NSSI) presents an increasingly prevalent problem for young people; however, there remains a scarce evidence base for effective, scalable treatments for adolescents. This study aimed to assess the feasibility and acceptability of a brief, cognitive analytic therapy (CAT)-informed intervention for young people who engage in NSSI (CATCH-Y).

METHODS

A case series design recruited 13 young people who met the inclusion and exclusion criteria to participate in the five-session intervention. Eligible participants were aged 13-17 years (M = 15.15, SD = 1.28) and had engaged in NSSI at least once in the previous 6 months. Feasibility and acceptability were measured via recruitment, retention, qualitative feedback and missing data. The secondary outcome measures of personal recovery and motivation were administered pre- and post-assessment, with measures of depressive symptoms and urges to self-injure.

RESULTS

The intervention was found to be largely feasible and acceptable with high rates of recruitment, retention and pre-/post-assessment data completeness. Measures showed preliminary support for positive change in rates of NSSI, urges to self-harm, low mood and personal recovery, although results were mixed. Completion rates for remote assessments were low.

CONCLUSIONS

The findings of this study support further evaluation of the CATCH-Y intervention on a larger scale. In-person assessments may be preferable to remote to ensure good completion rates.

Occult tension pneumothorax discovered following imaging for adult trauma patients in the modern major trauma system: a multicentre observational study

BACKGROUND

Tension pneumothorax following trauma is a life-threatening emergency and radiological investigation is normally discouraged prior to treatment in traditional trauma doctrines such as ATLS. Some trauma patients may be physiologically stable enough for diagnostic imaging and occult tension pneumothorax is discovered radiologically. We assessed the outcomes of these patients and compared them with those with clinical diagnosis of tension pneumothorax prior to imaging.

METHODS

A multicentre civilian-military collaborative network of six major trauma centres in the UK collected observational data from adult patients who had a diagnosis of traumatic tension pneumothorax during a 33-month period. Patients were divided into 'radiological' (diagnosis following CT/CXR) or 'clinical' (no prior CT/CXR) groups. The effect of radiological diagnosis on survival was analysed using multivariable logistic regression that included the covariates of age, gender, comorbidities and Injury Severity Score.

RESULTS

There were 133 patients, with a median age of 41 (IQR 24-61); 108 (81%) were male. Survivors included 49 of 59 (83%) in the radiological group and 59 of 74 (80%) in the clinical group (p=0.487). Multivariable logistic regression showed no significant association between radiological diagnosis and survival (OR 2.40, 95% CI 0.80 to 7.95; p=0.130). There was no significant difference in mortality between the groups.

CONCLUSION

Radiological imaging may be appropriate for selected trauma patients at risk of tension pneumothorax if they are considered haemodynamically stable. Trauma patients may be physiologically stable enough for radiological imaging but have occult tension pneumothorax because they did not have the typical clinical presentation. The historical dogma of the 'forbidden scan' no longer applies to such patients.

IFITM3 restricts virus-induced inflammatory cytokine production by limiting Nogo-B mediated TLR responses

Interferon-induced transmembrane protein 3 (IFITM3) is a restriction factor that limits viral pathogenesis and exerts poorly understood immunoregulatory functions. Here, using human and mouse models, we demonstrate that IFITM3 promotes MyD88-dependent, TLR-mediated IL-6 production following exposure to cytomegalovirus (CMV). IFITM3 also restricts IL-6 production in response to influenza and SARS-CoV-2. In dendritic cells, IFITM3 binds to the reticulon 4 isoform Nogo-B and promotes its proteasomal degradation. We reveal that Nogo-B mediates TLR-dependent pro-inflammatory cytokine production and promotes viral pathogenesis in vivo, and in the case of TLR2 responses, this process involves alteration of TLR2 cellular localization. Nogo-B deletion abrogates inflammatory cytokine responses and associated disease in virus-infected IFITM3-deficient mice. Thus, we uncover Nogo-B as a driver of viral pathogenesis and highlight an immunoregulatory pathway in which IFITM3 fine-tunes the responsiveness of myeloid cells to viral stimulation.

92 Evaluation of an Artificial Intelligence (AI) System to Augment Clinical Risk Prediction of Trauma Induced Coagulopathy: A Prospective Observational Study

Introduction

The potential of AI systems to support pre-hospital clinical decision-making is significant. However, whilst such algorithms are increasingly available, far less attention has been paid to understanding the impact of such systems on clinical performance. This study had two aims; first, to compare the performance of expert clinicians against an AI system in a real-world clinical setting and second, to assess the impact of augmenting expert clinical prediction with an AI system.

Method

We performed a prospective study at two UK Air Ambulances services over a six-month period. Expert pre-hospital clinicians’ judgement of the risk of Trauma Induced Coagulopathy (TIC) in injured patients was assessed and compared to the performance of an AI system. Two TIC risk predictions were generated for every patient: an AI prediction and a human prediction.

Results

Overall, 51 expert clinicians were enrolled in the study providing 184 patient interactions for analysis.

Aim 1

The AI system performed better than clinicians; higher discrimination [AUROC 0.87 (0.79, 0.95) versus 0.83 (0.74, 0.92)] better calibration [0.37 (-0.14, 0.89) versus -1.19 (-1.73, -0.65)] and more accurate [Brier Skill Score 0.34 (0.19, 0.48) versus 0.00 (-0.41, 0.30)].

Aim 2

Risk prediction was better in all performance metrics when clinicians were assisted with the AI system [AUROC 0.88 (0.80, 0.95) versus 0.83 (0.74, 0.92)]

Conclusions

AI systems can improve human risk prediction in the pre-hospital setting. In settings of low resources where a lack of senior clinical expertise may affect outcomes, the benefit of implementing predictive AI is substantial.

Suspected appendicitis and COVID-19, a change in investigation and management-a multicentre cohort study

Purpose

The COVID-19 pandemic has reformed global healthcare delivery. On 25 March 2020, Intercollegiate guidelines were published in the UK to promote safe surgical provision during the COVID-19 outbreak advocating non-operative management or avoidance of laparoscopy when surgery is essential. The effects of this on the investigation and management of appendicitis remain unknown.

Methods

We performed a multicentre, prospective, observational study from the start of the new guidelines to the 6th of May 2020. We included all patients referred to surgical teams with suspected appendicitis. A recent historical cohort was identified for comparison. The primary outcome was the impact of the COVID-19 pandemic on the use of non-operative management in appendicitis. Secondary outcomes included imaging, negative appendicectomy rate (NAR), length of stay (LOS) and 30-day complications.

Results

A total of 63/164 (38%) patients compared to 79/191 (41%) were diagnosed with appendicitis before and after the guidelines were introduced (p = 0.589). CT scanning increased (71/164 vs 105/191; p = 0.033) while ultrasound scanning decreased (71/164 vs 62/191; p = 0.037). Appendicitis was more likely to be managed non-operatively (11/63 vs 51/79; p < 0.001) and, of those managed surgically, with an open approach (3/52 vs 26/28 p < 0.001). The NAR also reduced (5/52 vs 0/28; p = 0.157). LOS was shorter in non-operatively managed patients (1 day vs 3 days; p < 0.001) without a difference in complications (10/51 vs 4/28; p = 0.760).

Conclusion

Introduction of the guidelines was associated with changes in practice. Despite these changes, short-term complications did not increase and LOS decreased. Questions remain on the longer-term complication rates in non-operatively managed patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00423-020-02023-6.

Torso body armour coverage defined according to feasibility of haemorrhage control within the prehospital environment: a new paradigm for combat trauma protection

Developments in military personal armour have aimed to achieve a balance between anatomical coverage, protection and mobility. When death is likely to occur within 60 min of injury to anatomical structures without damage control surgery, then these anatomical structures are defined as 'essential'. However, the medical terminology used to describe coverage is challenging to convey in a Systems Requirements Document (SRD) for acquisition of new armour and to ultimately translate to the correct sizing and fitting of personal armour. Many of those with Ministry of Defence responsible for the procurement of personal armour and thereby using SRDs will likely have limited medical knowledge; therefore, the potentially complex medical terminology used to describe the anatomical boundaries must be translated into easily recognisable and measurable external landmarks. We now propose a complementary classification for ballistic protection coverage, termed threshold and objective, based on the feasibility of haemorrhage control within the prehospital environment.

Killed in action (KIA): an analysis of military personnel who died of their injuries before reaching a definitive medical treatment facility in Afghanistan (2004-2014)

INTRODUCTION

The majority of combat deaths occur before arrival at a medical treatment facility but no previous studies have comprehensively examined this phase of care.

METHODS

The UK Joint Theatre Trauma Registry was used to identify all UK military personnel who died in Afghanistan (2004-2014). These data were linked to non-medical tactical and operational records to provide an accurate timeline of events. Cause of death was determined from records taken at postmortem review. The primary objective was to report time between injury and death in those killed in action (KIA); secondary objectives included: reporting mortality at key North Atlantic Treaty Organisation timelines (0, 10, 60, 120 min), comparison of temporal lethality for different anatomical injuries and analysing trends in the case fatality rate (CFR).

RESULTS

2413 UK personnel were injured in Afghanistan from 2004 to 2014; 448 died, with a CFR of 18.6%. 390 (87.1%) of these died prehospital (n=348 KIA, n=42 killed non-enemy action). Complete data were available for n=303 (87.1%) KIA: median Injury Severity Score 75.0 (IQR 55.5-75.0). The predominant mechanisms were improvised explosive device (n=166, 54.8%) and gunshot wound (n=96, 31.7%).In the KIA cohort, the median time to death was 0.0 (IQR 0.0-21.8) min; 173 (57.1%) died immediately (0 min). At 10, 60 and 120 min post injury, 205 (67.7%), 277 (91.4%) and 300 (99.0%) casualties were dead, respectively. Whole body primary injury had the fastest mortality. Overall prehospital CFR improved throughout the period while in-hospital CFR remained constant.

CONCLUSION

Over two-thirds of KIA deaths occurred within 10 min of injury. Improvement in the CFR in Afghanistan was predominantly in the prehospital phase.

Trends in admission timing and mechanism of injury can be used to improve general surgical trauma training

INTRODUCTION

The temporal patterns and unit-based distributions of trauma patients requiring surgical intervention are poorly described in the UK. We describe the distribution of trauma patients in the UK and assess whether changes in working patterns could provide greater exposure for operative trauma training.

METHODS

We searched the Trauma Audit and Research Network database to identify all patients between 1 January 2014 to 31 December 2016. Operative cases were defined as all patients who underwent laparotomy, thoracotomy or open vascular intervention. We assessed time of arrival, correlations between mechanism of injury and surgery, and the effect of changing shift patterns on exposure to trauma patients by reference to a standard 10-hour shift assuming a dedicated trauma rotation or fellowship.

RESULTS

There were 159,719 patients from 194 hospitals submitted to the Network between 2014 and 2016. The busiest 20 centres accounted for 57,568 (36.0%) of cases in total. Of these 2147/57,568 patients (3.7%) required a general surgical operation; 43% of penetrating admissions (925 cases) and 2.2% of blunt admissions (1222 cases). The number of operations correlated more closely with the number of penetrating rather than blunt admissions (r = 0.89 vs r = 0.51). A diurnal pattern in trauma admissions enabled significant increases in trauma exposure with later start times.

CONCLUSIONS

Centres with high volume and high penetrating rates are likely to require more general surgical input and should be identified as locations for operative trauma training. It is possible to improve the number of trauma patients seen in a shift by optimising shift start time.

Interferon-Induced Transmembrane Protein 1 Restricts Replication of Viruses That Enter Cells via the Plasma Membrane

The acute antiviral response is mediated by a family of interferon-stimulated genes (ISGs), providing cell-intrinsic immunity. Mutations in genes encoding these proteins are often associated with increased susceptibility to viral infections. One family of ISGs with antiviral function is the interferon-inducible transmembrane proteins (IFITMs), of which IFITM3 has been studied extensively. In contrast, IFITM1 has not been studied in detail. Since IFITM1 can localize to the plasma membrane, we investigated its function with a range of enveloped viruses thought to infect cells by fusion with the plasma membrane. Overexpression of IFITM1 prevented infection by a number of Paramyxoviridae and Pneumoviridae, including respiratory syncytial virus (RSV), mumps virus, and human metapneumovirus (HMPV). IFITM1 also restricted infection with an enveloped DNA virus that can enter via the plasma membrane, herpes simplex virus 1 (HSV-1). To test the importance of plasma membrane localization for IFITM1 function, we identified blocks of amino acids in the conserved intracellular loop (CIL) domain that altered the subcellular localization of the protein and reduced antiviral activity. By screening reported data sets, 12 rare nonsynonymous single nucleotide polymorphisms (SNPs) were identified in human IFITM1, some of which are in the CIL domain. Using an Ifitm1-/- mouse, we show that RSV infection was more severe, thereby extending the range of viruses restricted in vivo by IFITM proteins and suggesting overall that IFITM1 is broadly antiviral and that this antiviral function is associated with cell surface localization.IMPORTANCE Host susceptibility to viral infection is multifactorial, but early control of viruses not previously encountered is predominantly mediated by the interferon-stimulated gene (ISG) family. There are upwards of 300 of these genes, the majority of which do not have a clearly defined function or mechanism of action. The cellular location of these proteins may have an important effect on their function. One ISG located at the plasma membrane is interferon-inducible transmembrane protein 1 (IFITM1). Here we demonstrate that IFITM1 can inhibit infection with a range of viruses that enter via the plasma membrane. Mutant IFITM1 proteins that were unable to localize to the plasma membrane did not restrict viral infection. We also observed for the first time that IFITM1 plays a role in vivo, and Ifitm1-/- mice were more susceptible to viral lung infection. These data contribute to our understanding of how ISGs prevent viral infections.

Combined ultrasound and Sestamibi scintigraphy provides accurate preoperative localisation for patients with primary hyperparathyroidism

INTRODUCTION

Minimally invasive parathyroidectomy has advantages over the traditional bilateral neck exploration for the surgical treatment of primary hyperparathyroidism. It requires accurate localisation of the parathyroid pathology prior to surgery. The best method of preoperative localisation in a district general hospital setting is not well understood.

METHODS

All patients who underwent parathyroidectomy for primary hyperparathyroidism from 2008 to 2016 were identified from a prospectively maintained database. Operative findings were correlated with radiological and histological results. Sensitivity and specificity of ultrasound, sestamibi scintigraphy and the two together were calculated for diagnostic precision and compared.

RESULTS

One hundred and eighty-four patients met the inclusion criteria, of whom 81.5% had a histological diagnosis of a parathyroid adenoma. Ultrasound had higher sensitivity than sestamibi scintigraphy. Used together, ultrasound and sestamibi scintigraphy performed better than either ultrasound or sestamibi scintigraphy alone (P< 0.001). Twenty-two of 184 cases had no lesion located by either ultrasound or sestamibi scintigraphy preoperatively. Where neither ultrasound nor sestamibi scintigraphy located the lesion, additional computed tomography led to the excision of parathyroid pathology in one in ten patients.

CONCLUSION

The combination of ultrasound and sestamibi scintigraphy provides the highest sensitivity of preoperative localisation. This approach led to a high success rate of minimally invasive parathyroidectomy. Where preoperative localisation is not achieved with ultrasound or sestamibi scintigraphy, computed tomography adds little additional benefit. In this setting other modalities of localisation such a selective venous sampling, intraoperative methylene blue or intraoperative parathyroid hormone levels could be considered.

Critical care usage after major gastrointestinal and liver surgery: a prospective, multicentre observational study

BACKGROUND

Patient selection for critical care admission must balance patient safety with optimal resource allocation. This study aimed to determine the relationship between critical care admission, and postoperative mortality after abdominal surgery.

METHODS

This prespecified secondary analysis of a multicentre, prospective, observational study included consecutive patients enrolled in the DISCOVER study from UK and Republic of Ireland undergoing major gastrointestinal and liver surgery between October and December 2014. The primary outcome was 30-day mortality. Multivariate logistic regression was used to explore associations between critical care admission (planned and unplanned) and mortality, and inter-centre variation in critical care admission after emergency laparotomy.

RESULTS

Of 4529 patients included, 37.8% (n=1713) underwent planned critical care admissions from theatre. Some 3.1% (n=86/2816) admitted to ward-level care subsequently underwent unplanned critical care admission. Overall 30-day mortality was 2.9% (n=133/4519), and the risk-adjusted association between 30-day mortality and critical care admission was higher in unplanned [odds ratio (OR): 8.65, 95% confidence interval (CI): 3.51-19.97) than planned admissions (OR: 2.32, 95% CI: 1.43-3.85). Some 26.7% of patients (n=1210/4529) underwent emergency laparotomies. After adjustment, 49.3% (95% CI: 46.8-51.9%, P<0.001) were predicted to have planned critical care admissions, with 7% (n=10/145) of centres outside the 95% CI.

CONCLUSIONS

After risk adjustment, no 30-day survival benefit was identified for either planned or unplanned postoperative admissions to critical care within this cohort. This likely represents appropriate admission of the highest-risk patients. Planned admissions in selected, intermediate-risk patients may present a strategy to mitigate the risk of unplanned admission. Substantial inter-centre variation exists in planned critical care admissions after emergency laparotomies.

Cost-effectiveness of routine imaging of suspected appendicitis

Introduction The misdiagnosis of appendicitis and consequent removal of a normal appendix occurs in one in five patients in the UK. On the contrary, in healthcare systems with routine cross-sectional imaging of suspected appendicitis, the negative appendicectomy rate is around 5%. If we could reduce the rate in the UK to similar numbers, would this be cost effective? This study aimed to calculate the financial impact of negative appendicectomy at the Queen Alexandra Hospital and to explore whether a policy of routine imaging of such patients could reduce hospital costs. Materials and methods We performed a retrospective analysis of all appendicectomies over a 1-year period at our institution. Data were extracted on outcomes including appendix histology, operative time and length of stay to calculate the negative appendicectomy rate and to analyse costs. Results A total of 531 patients over 5 years of age had an appendicectomy. The negative appendicectomy rate was 22% (115/531). The additional financial costs of negative appendicectomy to the hospital during this period were £270,861. Universal imaging of all patients with right iliac fossa pain that could result in a 5% negative appendicectomy rate would cost between £67,200 and £165,600 per year but could save £33,896 (magnetic resonance imaging), £105,896 (computed tomography) or £132,296 (ultrasound) depending on imaging modality used. Conclusions Negative appendicectomy is still too frequent and results in additional financial burden to the health service. Routine imaging of patients with suspected appendicitis would not only reduce the negative appendicectomy rate but could lead to cost savings and a better service for our patients.

Defining our destiny: trainee working group consensus statement on the future of emergency surgery training in the United Kingdom

The United Kingdom National Health Service treats both elective and emergency patients and seeks to provide high quality care, free at the point of delivery. Equal numbers of emergency and elective general surgical procedures are performed, yet surgical training prioritisation and organisation of NHS institutions is predicated upon elective care. The increasing ratio of emergency general surgery consultant posts compared to traditional sub-specialities has yet to be addressed. How should the capability gap be bridged to equip motivated, skilled surgeons of the future to deliver a high standard of emergency surgical care? The aim was to address both training requirements for the acquisition of necessary emergency general surgery skills, and the formation of job plans for trainee and consultant posts to meet the current and future requirements of the NHS. Twenty nine trainees and a consultant emergency general surgeon convened as a Working Group at The Association of Surgeons in Training Conference, 2015, to generate a united consensus statement to the training requirement and delivery of emergency general surgery provision by future general surgeons. Unscheduled general surgical care provision, emergency general surgery, trauma competence, training to meet NHS requirements, consultant job planning and future training challenges arose as key themes. Recommendations have been made from these themes in light of published evidence. Careful workforce planning, education, training and fellowship opportunities will provide well-trained enthusiastic individuals to meet public and societal need.

An immune control model for viral replication in the CNS during presymptomatic HIV infection

The brain is targeted by human immunodeficiency virus type 1 (HIV-1) during the course of untreated infection, leading to cognitive impairment, neurological damage and HIV encephalitis (HIVE). To study early dynamics of HIV entry into the brain, we examined a unique autopsy series of samples obtained from 15 untreated individuals who died in the presymptomatic stages of infection from non-HIV causes. HIV was detected and quantified by limiting dilution PCR and genetically characterized in the V3 region of env. Limiting dilution was shown to be essential for correct estimation of genetic partitioning between brain- and lymphoid-associated HIV populations. While no actively expressing HIV-infected cells were detected by immunohistochemistry, variable and generally extremely low levels of proviral DNA were detected in presymptomatic brain samples. V3 region sequences were frequently genetically distinct from lymphoid-associated HIV variants, with association index (AI) values similar to those observed in cases of HIVE. Infiltration of CD8 lymphocytes in the brain was strongly associated with expression of activation markers (MHCII; R = 0.619; P < 0.05), the presence of HIV-infected cells (proviral load; R = 0.608; P < 0.05) and genetic segregation of brain variants from populations in lymphoid tissue (AI value, R = -0.528; P approximately 0.05). CD8 lymphocytes may thus limit replication of HIV seeded into the brain in early stages of infection. Neurological complications in AIDS occur when this control breaks down, due to systemic immunosuppression from HIV that destroys CD8 lymphocyte function and/or through the evolution of more aggressive neuropathogenic variants.

Regulation of cell polarity, radial intercalation and epiboly inXenopus: novel roles for integrin and fibronectin

Fibronectin (FN) is reported to be important for early morphogenetic movements in a variety of vertebrate embryos, but the cellular basis for this requirement is unclear. We have used confocal and digital time-lapse microscopy to analyze cell behaviors in Xenopus gastrulae injected with monoclonal antibodies directed against the central cell-binding domain of fibronectin. Among the defects observed is a disruption of fibronectin matrix assembly, resulting in a failure of radial intercalation movements, which are required for blastocoel roof thinning and epiboly. We identified two phases of FN-dependent cellular rearrangements in the blastocoel roof. The first involves maintenance of early roof thinning in the animal cap, and the second is required for the initiation of radial intercalation movements in the marginal zone. A novel explant system was used to establish that radial intercalation in the blastocoel roof requires integrin-dependent contact of deep cells with fibronectin. Deep cell adhesion to fibronectin is sufficient to initiate intercalation behavior in cell layers some distance from the substrate. Expression of a dominant-negative β1 integrin construct in embryos results in localized depletion of the fibronectin matrix and thickening of the blastocoel roof. Lack of fibronectin fibrils in vivo is correlated with blastocoel roof thickening and a loss of deep cell polarity. The integrin-dependent binding of deep cells to fibronectin is sufficient to drive membrane localization of Dishevelled-GFP, suggesting that a convergence of integrin and Wnt signaling pathways acts to regulate radial intercalation in Xenopus embryos.

The alphaBbetaC integrin is expressed on the surface of the sea urchin egg and removed at fertilization

Integrins are expressed on the surface of some vertebrate eggs where they are thought to have a role in fertilization. The objective of this study is to determine if integrins are expressed on sea urchin eggs. The alphaB and betaC subunits were cloned using the homology polymerase chain reaction. Monoclonal and polyclonal antibodies were developed against bacterially expressed fragments of the extracellular domains of the betaC subunit and the alphaB subunit. As well, a monoclonal antibody was developed against a synthesized peptide corresponding to part of the cytoplasmic domain of betaC. Analysis of biotinylated egg cortex extracts immunoprecipitated with either anti-betaC or anti-alphaB yields bands of 130 and 225 kDa. Immunoblots confirm that betaC is part of the complex immunoprecipitated with anti-alphaB. Confocal immunofluorescence and immunogold electron microscopy show that betaC is present on the surface of the unfertilized egg at the tips of microvilli and in cortical granules. During the cortical reaction, immunoreactivity with antibodies to the extracellular domains of betaC and alphaB disappears from the egg surface, and microvillar casts on the fertilization envelope become immunoreactive. With antibodies to the cytoplasmic domain of betaC, immunoreactivity is lost from the surface of the egg, but the fertilization envelope does not immediately become immunoreactive. In immunoblots of egg cortex there are immunoreactive bands of the predicted sizes for alphaB and betaC. However, in fertilization envelopes, a second band that is slightly lower in molecular weight is also present. Eggs fertilized in the presence of soybean trypsin inhibitor have elongated microvilli that remain bound to the elevating fertilization envelope and immunoreactive to anti-betaC antibodies. Eggs fertilized in the presence of an ovoperoxidase inhibitor, 3-amino-1,2,4-triazole, have a patchy distribution of betaC immunoreactivity in fertilization envelopes. Together, these data suggest that alphaBbetaC integrins are expressed on the surface of unfertilized eggs and, during the cortical reaction, the extracellular domains are cleaved by proteases and cross-linked into the fertilization envelope by ovoperoxidase. The alphaBbetaC integrin receptors may have several potential functions prior to their removal at fertilization, including attachment of the vitelline envelope to the egg surface and anchoring the cortical cytoskeleton.

Mosaic structure of the human immunodeficiency virus type 1 genome infecting lymphoid cells and the brain: evidence for frequent in vivo recombination events in the evolution of regional populations

In addition to immunodeficiency, human immunodeficiency virus type 1 (HIV-1) can cause cognitive impairment and dementia through direct infection of the brain. To investigate the adaptive process and timing of HIV-1 entry into the central nervous system, we carried out an extensive genetic characterization of variants amplified from different regions of the brain and determined their relatedness to those in lymphoid tissue. HIV-1 genomes infecting different regions of the brain of one study subject with HIV encephalitis (HIVE) had a mosaic structure, being assembled from different combinations of evolutionarily distinct lineages in p17(gag), pol, individual hypervariable regions of gp120 (V1/V2, V3, V4, and V5), and gp41/nef. Similar discordant phylogenetic relationships were observed between p17(gag) and V3 sequences of brain and lymphoid tissue from three other individuals with HIVE. The observation that different parts of the genome of HIV infecting a particular tissue can have different evolutionary histories necessarily limits the conclusions that can be drawn from previous studies of the compartmentalization of distinct HIV populations in different tissues, as these have been generally restricted to sequence comparisons of single subgenomic regions. The complexity of viral populations in the brain produced by recombination could provide a powerful adaptive mechanism for the spread of virus with new phenotypes, such as antiviral resistance or escape from cytotoxic T-cell recognition into existing tissue-adapted virus populations.

The betaL integrin subunit is necessary for gastrulation in sea urchin embryos

Integrins are a family of cell adhesion molecules reported to mediate cellular interactions essential for normal embryonic morphogenesis. Here we describe a beta integrin subunit that is expressed during early embryogenesis in the sea urchin embryo and appears to be necessary for normal development. The deduced amino acid sequence of betaL is similar to vertebrate beta integrin subunits, but is most closely related to the sea urchin betaG subunit. Northern blots show that betaL is expressed at all stages with maximum expression beginning during gastrulation. Immunolocalization and in situ RNA hybridization show that in blastulae betaL is expressed in the blastoderm and by the ring of bottle cells in the vegetal plate during the initial phase of gastrulation. Presumptive secondary mesenchyme cells express high levels of betaL throughout elongation of the archenteron and in the pluteus betaL is expressed by blastocoelar cells, skeletal mesenchyme, and pigment cells. Antibodies and Fab fragments against betaL block spreading of dissociated embryonic cells on RGD (arginine-glycine-aspartate)-containing substrates. Treating embryos with anti-betaL antibodies blocks the initial phase of gastrulation and interferes with the organization of actin filaments. Prior to gastrulation, the antibodies cause thickening of the blastoderm and later in development defects in skeletal patterning result. Probing for antibody in treated embryos indicates that it penetrates the ectoderm to cells within the blastocoel and is actively endocytosed. We propose that betaL forms receptors that bind to RGD-containing ligands and anchors actin filaments. These receptors appear to be essential in several aspects of morphogenesis.

Cloning and characterization of novel beta integrin subunits from a sea urchin

Cell surface molecules that mediate adhesion in sea urchin embryos have been implicated in morphogenesis, and yet the molecules remain largely uncharacterized. Here we report evidence from PCR amplification for three novel beta integrin subunits that are expressed during early development of Strongylocentrotus purpuratus. The full cDNA sequence for one of these, betaG, bears a 59% similarity to Drosophila betaPS and a 58% similarity to vertebrate integrins. betaG closely resembles the beta1 subunit of vertebrates, particularly in the cytoplasmic domain where amino acids of the human beta1 subunit implicated in cell adhesion and signaling are conserved. The betaG subunit is detectable as a maternal, 7.5-kb transcript in eggs and expression peaks during gastrulation. Immunoblots with antiserum raised against a bacterially expressed fragment of the betaG subunit have bands with apparent molecular weights of about 130 kDa under reducing conditions and 110 kDa under nonreducing conditions. Immunoprecipitations suggest that betaG associates with at least two alpha subunits in gastrula stage embryos. In situ RNA hybridization of the betaG subunit indicates that all cells of the embryo express this molecule prior to gastrulation. In gastrulae, hybridization of the probe is highest in primary mesenchyme, secondary mesenchyme, the developing gut, and pigment cells. In immunolocalizations all cells of the blastulae express the protein at low levels and primary mesenchyme cells express betaG after they enter the blastocoel. Expression of the protein appears to be downregulated in the archenteron throughout gastrulation. betaG protein expression is also evident on secondary mesenchyme as they ingress and migrate in the blastocoel. We conclude that sea urchin embryos express integrins that are structurally similar to those characterized in other animals. Because betaG is expressed by migrating mesenchyme and yet is downregulated by rearranging epithelia, we suggest that this subunit has several functions during early development.

Effect of N-acetyl cysteine on the concentrations of thiols in plasma, bronchoalveolar lavage fluid, and lung tissue

BACKGROUND

Oxidant/antioxidant imbalance may occur in the lungs of patients with chronic obstructive pulmonary disease (COPD). Glutathione is an important extracellular and intracellular thiol oxidant in the lungs. These studies were carried out to determine the effect of N-acetyl cysteine on thiol concentrations in plasma, bronchoalveolar lavage fluid, and lung tissue.

METHODS

Studies were carried out on normal subjects, patients with COPD, and those undergoing lung resection. In the first study N-acetyl cysteine was given to three groups; healthy subjects (600 mg once daily by mouth) and two groups of patients with COPD. In the first group of patients with COPD the dose was 600 mg once daily and in the second 600 mg thrice daily, all for five days. The latter dosage regimen was also given to six patients before bronchoscopy and to 11 patients before lung resection. Lung glutathione (GSH) levels in bronchoalveolar lavage fluid or lung tissue were compared with the same numbers of patients who did not receive N-acetyl cysteine.

RESULTS

N-acetyl cysteine was detected in plasma after a single 600 mg dose in normal subjects and patients with COPD up to 1.5 hours after the drug was given. Plasma cysteine concentrations increased in normal subjects on both days 1 and 5, and in patients with COPD on day 5. Glutathione concentrations in plasma increased on day 1 in normal subjects but not in patients with COPD given 600 mg N-acetyl cysteine daily. With the higher dose of 600 mg thrice daily, however, there was a sustained elevation of GSH concentrations in plasma in patients with COPD. In patients undergoing routine diagnostic bronchoscopy and bronchoalveolar lavage those who were given N-acetyl cysteine (600 mg) thrice daily for five days had higher concentrations of cysteine in the plasma, but no significant differences in cysteine concentrations in bronchoalveolar lavage or epithelial lining fluid compared with a control group; nor were there any differences in reduced glutathione concentrations in plasma, bronchoalveolar lavage or epithelial lining fluids between the control and treated groups. Moreover, in patients undergoing lung resection those treated with N-acetyl cysteine (600 mg thrice daily for five days) had similar concentrations of cysteine and glutathione in both plasma and lung tissue when compared with a control untreated group.

CONCLUSIONS

These data suggest that, even when given in high oral doses, N-acetyl cysteine does not produce a sustained increase in glutathione levels sufficient to increase the antioxidant capacity of the lungs.

The induction of pyruvate kinase synthesis by heat shock in Xenopus laevis embryos

Heat-shocked Xenopus embryos have an unusually complex heat shock response. The dominant heat shock protein (Hsp) has a relative molecular mass (M(r)) of 62,000 D (Hsp62). Affinity-purified IgGs against the glycolytic enzyme pyruvate kinase (PK; EC 2.7.1.40) specifically immunoprecipitated Hsp62 from extracts of embryos that had been heat-shocked at 37 degrees C for 30 min. Thus, Hsp62 and pyruvate kinase are immunologically cross-reacting. Electrophoretic separation of PK isoforms suggests that heat-shocked Xenopus embryos increase synthesis of an isoform of PK. Thermal denaturation studies suggest that this isoform has enhanced thermal stability. The identification of PK as an Hsp is discussed within the context of a physiological requirement for elevated levels of anaerobic glycolysis in heat-stressed cells as a vital component of the acquisition of thermotolerance.

The effects of N-acetylcysteine and glutathione on smoke-induced changes in lung phagocytes and epithelial cells

We studied the mechanism of the delay in neutrophil traffic in pulmonary microvasculature previously observed during cigarette smoking, the effect of cigarette smoke on lung phagocytes and epithelial cell function, and augmentation of the glutathione (GSH) antioxidant system using the thiol drug N-acetylcysteine. Using a micropore membrane system to mimic the dimensions of the average pulmonary capillary, we showed that cigarette smoke reduces cell deformability, increasing the difficulty experienced by the larger neutrophils in negotiating the smaller capillary segments, so delaying their passage during smoking. This effect is both diminished and recoverable by the addition of plasma, and by GSH in concentrations found in plasma. Cigarette smoke induces oxidative changes in both the cell membrane and the cell cytoskeleton, and diminishes the ability of neutrophils to release reactive oxygen intermediates. The injurious effect of oxidants can be measured in vitro by the detachment of 51Cr-radiolabeled alveolar epithelial cells grown in monolayers, an effect also diminished by the addition of GSH. Such epithelial cell detachment in vitro may be reflected as the epithelial permeability that occurs at an early stage in asymptomatic smokers. N-Acetylcysteine given orally (600 mg/day) increases both plasma and bronchoalveolar lavage GSH in normal subjects, but a sustained increase in plasma GSH requires higher dosage regimens in patients with chronic obstructive pulmonary disease (600 mg three times daily). Thus, the potential exists to enhance the antioxidant status of both plasma and the airspaces of the lungs against oxidant-induced injury.

Cysteine and glutathione concentrations in plasma and bronchoalveolar lavage fluid after treatment with N-acetylcysteine

N-acetylcysteine (600 mg/day) was given to patients by mouth for five days before bronchoscopy and bronchoalveolar lavage to determine whether N-acetylcysteine could increase the concentrations of the antioxidant reduced glutathione in plasma and bronchoalveolar lavage fluid. Bronchoalveolar lavage was performed 1-3 hours (group 2, n = 9) and 16-20 hours (group 3, n = 10) after the last dose of N-acetylcysteine and the values were compared with those in a control group receiving no N-acetylcysteine (group 1, n = 8). N-acetylcysteine was not detected in plasma or lavage fluid. Plasma concentrations of cysteine, the main metabolite of N-acetylcysteine and a precursor of reduced glutathione, were greater in the groups receiving treatment (groups 2 and 3) than in group 1. Cysteine concentrations in lavage fluid were similar in the three groups. Concentrations of reduced glutathione were greater in both plasma and lavage fluid in group 2 than in group 1. These data suggest that N-acetylcysteine given by mouth is rapidly deacetylated to cysteine, with resulting increases in the concentrations of cysteine in plasma and of reduced glutathione in plasma and the airways, which thus temporarily increase the antioxidant capacity of the lung.

Initial studies on leucine metabolism in the rumen of sheep

1. [3H]leucine infused directly into the rumen of sheep labelled microbial protein and, when compared with the specific activity of the rumen free-leucine pool, indicated that 50% of the bacterial protein leucine originated from the rumen free-leucine pool. 2. The lower limit for bacterial protein turnover in the rumen was 0.37/d when calculated as the difference between the specific rate of disappearances of labelled bacteria from the rumen and the liquid-phase dilution rate. 3. Intravenously infused leucine also labelled the rumen bacteria. The build-up of specific activity in the rumen bacteria was sigmoidal and did not resemble that of the salivary protein which suggested that the rumen epithelium was a major endogenous protein input to the rumen. Additionally, bacteria isolated from the rumen epithelium had high radioactivity indicating that they were ingesting the rumen epithelial cells.

In vitro differentiation of teratomas and the distribution of creatine phosphokinase and plasminogen activator in teratocarcinoma-derived cells

Mouse teratocarcinoma cells from embryoid bodies were cultured in vitro to permit their differentiation into a number of cell types. Two enzyme activities, creatine phosphokinase (CPK) and the protease plasminogen activator, were studied to follow the developmental sequence of events in these embryoid body-derived cell cultures. CPK activity increased with time in culture, indicating the appearance of new cell types with brain- or muscle-specific enzyme activities. Plasminogen activator was detectable in extracts of embryoid bodies. This protease activity first increased and then decreased to a low level as the embryoid bodies in culture developed into differentiated cell types. These cell cultures also showed a decreased potential for tumor formation in syngeneic mice as a function of time in culture. This decrease in tumorigenic potential was correlated with the appearance of differentiated cells in vitro. Simian virus 40 (SV40) was used to infect and transform cells derived from embryoid bodies in culture. This was done to permit the establishment of cloned teratocarcinoma-derived cell lines. Twenty-nine distinct cloned permanent cell lines (called SVTER) containing the SV40-specific tumor antigen were obtained. None of these cell lines was capable of producing tumors in syngeneic mice. An analysis of the levels of creatine phosphokinase and plasminogen activator in these SVTER cell lines indicated that : (a) some cell lines had high CPK activity and little or no plasminogen activator activity, (b) some cell lines contained high levels of plasminogen activator activity with little or no CPK activity, and (c) some cell lines contained neither of these enzyme activities. No example of a cell line with high levels of both enzyme activities was observed, indicating that these two enzymes may participate in mutually exclusive developmental pathways. The SVTER cell lines may therefore be useful in reconstructing these developmental pathways in vitro.