Surgical margin in hepatic resection for colorectal metastasis: a critical and improvable determinant of outcome

OBJECTIVE

To update the analysis of technical and biologic factors related to hepatic resection for colorectal metastasis in a large single-institution series to identify important prognostic indicators and patterns of failure.

SUMMARY BACKGROUND DATA

Surgical therapy for colorectal carcinoma metastatic to the liver is the only potentially curable treatment. Careful patient selection of those with resectable liver-only metastatic disease is crucial to the success of surgical therapy.

METHODS

Two hundred forty-four consecutive patients undergoing curative hepatic resection for metastatic colorectal carcinoma were analyzed retrospectively. Variables examined included sex, stage of primary lesion, size of liver lesion(s), number of lesions, disease-free interval, ploidy, differentiation, preoperative carcinoembryonic antigen level, and operative factors such as resection margin, use of cryotherapy, intraoperative ultrasound, and blood loss.

RESULTS

Surgical margin, number of lesions, and carcinoembryonic antigen (CEA) levels significantly control prognosis. Patients with only one or two liver lesions, a 1-cm surgical margin, and low CEA levels have a 5-year disease-free survival rate of more than 30%. Disease-free interval, original stage, bilobar involvement, size of metastasis, differentiation, and ploidy were not significant predictors of recurrence. The pattern of failure correlates with surgical margin. Routine use of intraoperative ultrasound resulted in an increased incidence of negative surgical margin during the period examined.

CONCLUSIONS

Surgical resection or cryotherapy of hepatic metastasis from colorectal cancer is safe and curable in appropriately selected patients. Biologic factors, such as number of lesions and carcinoembryonic antigen levels, determine potential curability, and surgical margin governs the patterns of failure and outcome in potentially curable patients. Optimization of selection criteria and surgical resection margins will improve outcome.

B lymphocytes express and lose syndecan at specific stages of differentiation

Lymphopoietic cells require interactions with bone marrow stroma for normal maturation and show changes in adhesion to matrix during their differentiation. Syndecan, a heparan sulfate-rich integral membrane proteoglycan, functions as a matrix receptor by binding cells to interstitial collagens, fibronectin, and thrombospondin. Therefore, we asked whether syndecan was present on the surface of lymphopoietic cells. In bone marrow, we find syndecan only on precursor B cells. Expression changes with pre-B cell maturation in the marrow and with B-lymphocyte differentiation to plasma cells in interstitial matrices. Syndecan on B cell precursors is more heterogeneous and slightly larger than on plasma cells. Syndecan 1) is lost immediately before maturation and release of B lymphocytes into the circulation, 2) is absent on circulating and peripheral B lymphocytes, and 3) is reexpressed upon their differentiation into immobilized plasma cells. Thus, syndecan is expressed only when and where B lymphocytes associate with extracellular matrix. These results indicate that B cells differentiating in vivo alter their matrix receptor expression and suggest a role for syndecan in B cell stage-specific adhesion.

The synovial membrane in osteoarthritis: a histological study including the characterisation of the cellular infiltrate present in inflammatory osteoarthritis using monoclonal antibodies

Inflammatory infiltration of the synovial membrane has been described in a proportion of cases of osteoarthritis (OA). Using conventional histology, lymphoid follicles, diffuse fibrosis, and perivascular fibrosis were shown to be present to a significantly greater extent and in more synovial membranes in osteoarthritis than in those cases where there was a mechanical or traumatic background to the joint disease. Calcium pyrophosphate dihydrate crystals (five patients) and detritus fragments of bone and cartilage (seven patients) were present in small numbers of the total cases of OA (38) studied. Neither of these features was related to the presence of an inflammatory infiltrate. Examination of 20 osteoarthritic synovial membranes using monoclonal antibodies showed the presence of lymphoid follicles containing T helper and T suppressor lymphocytes, B lymphocytes, and macrophages expressing HLA-DR in five cases. The T helper:suppressor ratio varied between 1:1 and 2.5:1 in these follicles. In addition, half of the OA samples, including these five cases, showed the presence of a diffuse cellular infiltrate containing T and B lymphocytes and macrophages, which were HLA-DR positive. Granulocytes were present in this diffuse infiltrate in those cases containing lymphoid follicles. The results confirm the presence of an inflammatory form of osteoarthritis but also show that the proportions of lymphoid cells are not the same as those considered to be typical of rheumatoid arthritis.

A cationic lipid-formulated plasmid DNA vaccine confers sustained antibody-mediated protection against aerosolized anthrax spores

DNA vaccines provide an attractive technology platform against bioterrorism agents due to their safety record in humans and ease of construction, testing, and manufacture. We have designed monovalent and bivalent anthrax plasmid DNA (pDNA) vaccines encoding genetically detoxified protective antigen (PA) and lethal factor (LF) proteins and tested their immunogenicity and ability to protect rabbits from an aerosolized inhalation spore challenge. Immune responses after two or three injections of cationic lipid-formulated PA, PA plus LF, or LF pDNAs were at least equivalent to two doses of anthrax vaccine adsorbed (AVA). High titers of anti-PA, anti-LF, and neutralizing antibody to lethal toxin (Letx) were achieved in all rabbits. Eight or nine animals in each group were challenged with 100x LD(50) of aerosolized anthrax spores 5 or 9 weeks after vaccination. An additional 10 animals vaccinated with PA pDNA were challenged >7 months postvaccination. All animals receiving PA or PA plus LF pDNA vaccines were protected. In addition, 5 of 9 animals receiving LF pDNA survived, and the time to death was significantly delayed in the others. Groups receiving three immunizations with PA or PA plus LF pDNA showed no increase in anti-PA, anti-LF, or Letx neutralizing antibody titers postchallenge, suggesting little or no spore germination. In contrast, titer increases were seen in AVA animals, and in surviving animals vaccinated with LF pDNA alone. Preclinical evaluation of this cationic lipid-formulated bivalent PA and LF vaccine is complete, and the vaccine has received U.S. Food and Drug Administration Investigational New Drug allowance.

Multicentre prospective cohort study of body mass index and postoperative complications following gastrointestinal surgery

BACKGROUND

There is currently conflicting evidence surrounding the effects of obesity on postoperative outcomes. Previous studies have found obesity to be associated with adverse events, but others have found no association. The aim of this study was to determine whether increasing body mass index (BMI) is an independent risk factor for development of major postoperative complications.

METHODS

This was a multicentre prospective cohort study across the UK and Republic of Ireland. Consecutive patients undergoing elective or emergency gastrointestinal surgery over a 4-month interval (October-December 2014) were eligible for inclusion. The primary outcome was the 30-day major complication rate (Clavien-Dindo grade III-V). BMI was grouped according to the World Health Organization classification. Multilevel logistic regression models were used to adjust for patient, operative and hospital-level effects, creating odds ratios (ORs) and 95 per cent confidence intervals (c.i.).

RESULTS

Of 7965 patients, 2545 (32·0 per cent) were of normal weight, 2673 (33·6 per cent) were overweight and 2747 (34·5 per cent) were obese. Overall, 4925 (61·8 per cent) underwent elective and 3038 (38·1 per cent) emergency operations. The 30-day major complication rate was 11·4 per cent (908 of 7965). In adjusted models, a significant interaction was found between BMI and diagnosis, with an association seen between BMI and major complications for patients with malignancy (overweight: OR 1·59, 95 per cent c.i. 1·12 to 2·29, P = 0·008; obese: OR 1·91, 1·31 to 2·83, P = 0·002; compared with normal weight) but not benign disease (overweight: OR 0·89, 0·71 to 1·12, P = 0·329; obese: OR 0·84, 0·66 to 1·06, P = 0·147).

CONCLUSION

Overweight and obese patients undergoing surgery for gastrointestinal malignancy are at increased risk of major postoperative complications compared with those of normal weight.

Type IV collagen and laminin in the synovial intimal layer: an immunohistochemical study

The distribution of type IV collagen and laminin in the intimal layer of rheumatoid, osteoarthritic, traumatic and normal human synovium was determined by immunohistochemistry using polyclonal and monoclonal antibodies. All samples showed a similar pattern of labelling with type IV collagen and laminin present around the synovial intimal cells. Type IV collagen has previously only been identified in association with basement membranes which are not found at this site. Two major basement membrane components around synovial cells suggest the formation of a modified basement membrane-like structure.

Adhesion of flowing leucocytes to immobilized platelets

Adhesion of neutrophils, lymphocytes and promyelocytic HL60 cells was compared in a flow-based model in which a monolayer of activated platelets formed the adhesive substrate. Each type of leucocyte formed P-selectin-mediated rolling attachments on the platelet surface under physiologically relevant flow conditions. Lymphocytes adhered less, and HL60 in similar numbers, compared to neutrophils, whereas the lymphocytes and HL60 cells rolled much more rapidly. Sulphated, sialylated saccharide(s) were implicated as ligand(s) for P-selectin for all leucocytes, but L-selectin (borne by neutrophils and lymphocytes, but not HL60 cells) appears to be a major presenter of ligand for neutrophils alone. T cells enriched from peripheral blood lymphocytes adhered in greater numbers than B cells. Differentiation of HL60 cells to neutrophil-like cells (induced by DMSO) caused cell volume to decrease and surface expression of integrin adhesion molecules to increase, but only a small percentage of cells were converted to an L-selectin-bearing phenotype. Differentiated cells showed evidence of stabilization of adhesion with increasing stress and a marked reduction in rolling velocity. These studies indicate that cell differentiation may be accompanied by alteration of adhesive behaviour, resulting from changes in physical characteristics as well as surface properties. Moreover, results suggest that P-selectin could promote lymphocyte attachment to endothelium in acute inflammatory conditions and possibly mediate lymphocyte-platelet interaction during thrombosis.

Heparin therapy for ulcerative colitis? Effects and mechanisms

Despite intensive medical treatment with steroids and immunosuppressants, acute colitis is still associated with a colectomy rate of up to 15%. Following the observation that a patient with severe steroid-resistant colitis went into remission when treated with heparin for a deep vein thrombosis, there have been a number of reports on the use of heparin in acute ulcerative colitis. Although small and uncontrolled, these studies consistently demonstrate the beneficial effects of heparin, with surprisingly few side-effects in a disease characterized by mucosal haemorrhage. The mechanisms by which heparin may ameliorate ulcerative colitis remain unclear. A simple anticoagulant effect may be responsible, but similar effects are not seen with warfarin. As a result of their intense negative charge, the glycosaminoglycans that constitute heparin have diverse biological effects. These include potent anti-inflammatory actions, in vitro and in vivo, and the potentiation of the activity of the peptide growth factors necessary for mucosal regeneration and repair. This review summarizes the clinical reports on heparin treatment for ulcerative colitis and explores the mechanisms by which this novel form of treatment may exert its effects.

Endothelial interactions of neutrophils under flow in chronic obstructive pulmonary disease

It is generally accepted that the neutrophil is central to the pathogenesis of chronic obstructive pulmonary disease (COPD). Enhanced endothelial interactions of this cell may contribute to the susceptibility of smokers who develop the disease; however, these interactions have not previously been studied in COPD. The aim of the current study was to determine whether enhanced endothelial interactions of neutrophils from smokers are a predisposing factor for the development of COPD. Endothelial interactions under flow and adhesion molecule expression of peripheral blood neutrophils were compared between seven never-smokers (NS), seven healthy smokers (HS), 11 COPD patients with severe alpha1-antitrypsin deficiency (PiZ) and neutrophils from 11 COPD patients without the deficiency (PiM). Total adhesive and migratory responses (per mm2 endothelium per 10(6) neutrophils) were significantly greater in the PiM group (mean+/-se 704.2+/-57.9 versus 509.3+/-48.8 in the PiZ group, 499.3+/-40.1 in the HS and 491.2+/-33.7 in the NS). This corresponded with increased macrophage antigen-1 (CD11b) expression on stimulated neutrophils in the PiM group compared with the PiZ group (mean+/-se relative fluorescence intensity 1.4+/-0.1 versus 1.1+/-0.1). In conclusion, the enhanced endothelial interaction of neutrophils from smokers who have developed chronic obstructive pulmonary disease in the presence of normal levels of alpha1-antitrypsin deficiency, but not in those with severe alpha(1)-antitrypsin deficiency, suggests that this is a predisposing factor for the development of the disease, and upregulation of macrophage antigen-1 may be responsible.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Pre and Post-exposure Prophylaxis Awareness and Acceptability Among Sex Workers in Jamaica: A Cross-Sectional Study

The HIV prevention cascade is understudied among sex workers in Jamaica, where sex work and same sex practices are criminalized. We implemented a cross-sectional survey with cisgender women, transgender women, and cisgender men sex workers in Jamaica. We conducted multivariable logistic regression analyses to identify factors associated with PrEP and PEP awareness and acceptability. Participants (n = 340) included cisgender men (n = 124), transgender women (n = 101), and cisgender women (n = 115). PEP awareness was low (33.2%), yet acceptability was high (70.8%). In multivariable analyses, recent sexual violence, recent client violence, and sex work social cohesion were associated with PEP awareness and acceptability. One-third (32.7%) reported PrEP awareness, with high acceptability (80.2%). Relationship status and recent physical violence were associated with PrEP awareness and acceptability. In multivariable analyses, gender identity was not associated with differences in PEP/PrEP awareness/acceptability. Findings highlight the need to increase PEP and PrEP awareness and access among sex workers in Jamaica.

Salmonella enterica biofilm formation and density in the Centers for Disease Control and Prevention's biofilm reactor model is related to serovar and substratum

Foodborne pathogens can attach to, and survive on, food contact surfaces for long periods by forming a biofilm. Salmonella enterica is the second most common cause of foodborne illness in Ireland. The ability of S. enterica to form a biofilm could contribute to its persistence in food production areas, leading to cross-contamination of products and surfaces. Arising from a large foodborne outbreak of S. enterica serovar Agona associated with a food manufacturing environment, a hypothesis was formulated that the associated Salmonella Agona strain had an enhanced ability to form a biofilm relative to other S. enterica. To investigate this hypothesis, 12 strains of S. enterica, encompassing three S. enterica serovars, were assessed for the ability to form a biofilm on multiple food contact surfaces. All isolates formed a biofilm on the contact surfaces, and there was no consistent trend for the Salmonella Agona outbreak strain to produce a denser biofilm compared with other strains of Salmonella Agona or Salmonella Typhimurium. However, Salmonella Enteritidis biofilm was considerably less dense than Salmonella Typhimurium and Salmonella Agona biofilms. Biofilm density was greater on tile than on concrete, polycarbonate, stainless steel, or glass.

Pathways from Police, Intimate Partner, and Client Violence to Condom Use Outcomes among Sex Workers in Jamaica

BACKGROUND

Violence reduces sex workers' ability to enforce consistent condom use. Less is known of violence and condom use among gender diverse sex workers in Jamaica, where both sex work and same-sex practices are criminalized. We examined pathways from violence to consistent condom use among sex workers in Jamaica.

METHODS

We conducted a cross-sectional survey with a peer-driven sample of sex workers (n = 340: n = 124 cisgender men, n = 115 cisgender women, n = 101 transgender women) in Kingston, Ocho Rios, and Montego Bay, Jamaica. We conducted structural equation modeling using weighted least square estimation methods to test the direct effects of police harassment (ever), intimate partner violence (IPV) (ever), and recent (past 6-month) client violence on consistent condom use, and indirect effects via condom use self-efficacy, adjusting for socio-demographic factors. Moderation analysis was conducted to estimate the effect of binge drinking on condom use self-efficacy. We conducted a second SEM taking into consideration measurement invariance to test gender differences.

RESULTS

Over half of participants reported police harassment, half intimate partner violence, and one-third client violence. Overall, the direct path from police harassment to consistent condom use was significant. Condom use self-efficacy mediated associations between client violence and IPV with consistent condom use. Binge drinking moderated the association between client violence and condom use self-efficacy. There were gender differences in these pathways.

CONCLUSIONS

Violence has direct and indirect effects on condom use outcomes among sex workers in Jamaica. Multilevel, gender-tailored interventions at policy, police, and community levels can promote sex workers' health and human rights.

Exploring associations between place of sex work and HIV vulnerabilities among sex workers in Jamaica

Sex workers' work environment shapes HIV transmission dynamics. We applied the Structural HIV Determinants Framework to examine associations between the work environment of public spaces and HIV infection risks among sex workers in Jamaica, considering macro-structural (police harassment) and intrapersonal (depression) pathways. We implemented a cross-sectional survey with sex workers in Kingston, Ocho Rios, Montego Bay, and nearby towns in Jamaica. We conducted structural equation modeling to examine direct and indirect associations between place of sex work on HIV serostatus via mediators of police harassment and depression. Results indicate that public place of sex work had a significant indirect effect on self-reported HIV-positive serostatus; depression and police harassment mediated this relationship. Findings suggest that in contexts of criminalization, the sex work environment can elevate exposure to police violence and depression, in turn increasing HIV vulnerabilities.

Impact of postoperative acute kidney injury in patients undergoing major gastrointestinal surgery on 1-year survival and renal outcomes: a national multicentre cohort study

BACKGROUND

The intermediate-term impact of acute kidney injury (AKI) in patients after major gastrointestinal and liver surgery has not been well characterized. This study aimed to evaluate the 1-year mortality rate and renal outcomes associated with postoperative AKI in a national prospective cohort.

METHODS

This prospective multicentre, observational cohort with 1-year postoperative follow-up included adults undergoing major gastrointestinal and liver surgery across the UK and Ireland between 23 September and 18 November 2015. AKI was defined according to Kidney Disease Improving Global Outcomes (KDIGO) criteria. The primary outcome was death at 1-year after surgery, and the secondary outcome was Major Adverse Kidney Events (MAKE-365). Cox proportionate and multilevel logistic regression were used to account for case mix.

RESULTS

Of 5745 patients across 173 centres, 1-year follow-up data was completed for 3504 patients (62.2 per cent, 126 centres), with attrition largely explained by centre non-participation (63.1 per cent). Some 13.6 per cent (475 of 3504) patients developed AKI by 7 days after surgery (stage 1: 9.2 per cent; stage 2/3: 4.3 per cent). At 1 year, 10.8 per cent (378 patients) experienced a MAKE-365 endpoint (303 patients had died, 61 had renal replacement therapy and 78 had renal dysfunction). Patients who experienced AKI by 7 days after surgery had a higher hazard of death at 1 year for KDIGO stage 1 (hazard ratio 1.50 (95 per cent c.i. 1.08 to 2.08), P = 0.016) and KDIGO stage 2/3 (hazard ratio 2.96 (95 per cent c.i. 2.02 to 4.33), P < 0.001). Both KDIGO stage 1 (odds ratio 2.09 (95 per cent c.i. 1.50 to 2.92), P < 0.001) and stage 2/3 (odds ratio 9.26 (95 per cent c.i. 6.31 to 13.59), P < 0.001) AKI were independently associated with MAKE-365.

CONCLUSION

AKI events within 7 days after gastrointestinal or liver surgery are associated with significantly worse survival and renal outcomes at 1 year.

Abstract P6-04-01: Engineering mesenchymal stem cells(MSCs) to secrete tumour-suppressing exosomes for breast cancer therapy

Introduction: Mesenchymal Stem Cells(MSCs) are multipotent stromal cells that are known to engraft into tumours, raising their potential as tumour-targeted delivery vehicles. MSCs secrete tiny vesicles known as exosomes, which contain genetic material including microRNAs, and are effectively taken up by recipient cells. This study aimed to characterise a tumour-suppressing microRNA, miR-379, and engineer MSCs to secrete exosomes enriched with the microRNA.

Methods: The mechanism of action of miR-379 In Vivo was determined through lentivirus-mediated upregulation of miR-379 in breast tumours, and analysis of changes in tumour angiogenesis, proliferation and progression. Subsequently, MSCs were engineered with lenti-379 and any impact on MSC migration, proliferation and morphology was assessed. MSC-secreted exosomes were isolated and characterised using Transmission Electron Microscopy(TEM) and Western Blot. The exosomal microRNA content was analysed by RQ-PCR, and transfer between cell populations visualised using confocal microscopy.

Results: While elevated miR-379 expression did not impact tumour size In Vivo, an increase in tumour necrosis and decrease in invasion was observed. MSCs were successfully transduced with miR-379, resulting in a distinct change in cell morphology. Despite this, MSC-379 cells maintained inherent tumour-targeted migratory capacity, with no impact on proliferation observed. MSC-379 derived exosomes were 30-120nm in size and expressed the exosome-associated protein CD63. A 5-fold increase in miR-379 was observed in engineered exosomes. Successful transfer of RFP-labelled MSC-derived exosomes to breast cancer cells was visualised using confocal microscopy.

Conclusion: Engineering tumour-targeted MSCs to secrete exosomes enriched with miR-379 holds exciting potential as a novel therapy for breast cancer.

Citation Format: O'Brien KP, Khan S, Thompson K, Joyce D, Lalor P, Dockery P, Ingoldsby H, Kerin MJ, Dwyer RM. Engineering mesenchymal stem cells(MSCs) to secrete tumour-suppressing exosomes for breast cancer therapy [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-04-01.

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.

Molecular cloning, reconstruction and expression of the gene encoding the alpha-chain of the bovine CD8--definition of three peptide regions conserved across species

We report the cloning of a cDNA encoding the alpha-chain of the bovine CD8 (BoCD8 alpha). A bovine thymus cDNA library was hybridized at low stringency with a human CD8 alpha cDNA clone. The first round of screening of 5 x 10(4) independent colonies yielded 12 clones containing incomplete BoCD8 alpha genes. Two further rounds of colony hybridization were conducted, each using as a probe the 5' fragment from the longest BoCD8 alpha clone previously isolated. The final screening yielded a clone containing a 2 kilobase (kb) insert. We mapped and sequenced the 2 kb BoCD8 alpha clone and compared it with the published sequences of the genes encoding the human, mouse and rat CD8 alpha. Sequence analysis confirmed that the clone under study encoded the BoCD8 alpha. The overall similarity of the BoCD8 alpha coding region with the human CD8 alpha coding sequence is 74.7% at the nucleotide level and 62.1% at the protein level. Lower levels of similarity are found with the mouse and rat CD8 alpha. Interestingly, three separate highly homologous regions are clearly defined at the peptide level in bovine versus human and mouse versus rat comparisons. Two of the regions are highly conserved among all species analysed, while the most 5' region is not. We speculate that the latter region may contain the binding site of CD8 alpha to the alpha 3 domain of major histocompatibility complex (MHC) class I molecules. Sequence analysis showed that the 2 kb BoCD8 alpha clone contains an incomplete coding region, i.e. lacks six bases corresponding to the first two amino acids of the leader region. To allow efficient translation and processing of the BoCD8 alpha gene, we constructed a chimeric gene containing the coding sequence of the BoCD8 alpha clone and synthetic sequences corresponding to the first two amino acids of the human CD8 alpha leader sequence. The chimeric gene was subcloned in the pKSV10 expression vector. The pKSV10-BoCD8 alpha construct is efficiently expressed both transiently in COS cells and stably in L cells, as determined by Northern blot and by FACS analysis, using the ILA-51 monoclonal antibody to BoCD8 alpha. The latter result formally proves that the ILA-51 antibody does indeed recognize the product of the BoCD8 alpha gene, as previously suggested on serological grounds.

In vivo effects of hyperdiploid Ly-1+ B cells of NZB origin

Cells with increased chromosome number and DNA content have been found in the spleens of old NZB mice. These hyperdiploid cells are of clonal origin and demonstrate discrete IgH chain gene rearrangements by Southern blot analysis. In this report, hyperdiploid cells were analyzed by three-color flow cytometric techniques and found to be Ly-1+ B cells which were dull for Ly-1 and bright for surface IgM. These cells, unlike typical diploid Ly-1+ B cells, were negative for B220/6B2 and surface IgD. Hyperdiploid Ly-1+ B cells were found to be the predominant splenic subpopulation in animals receiving a spleen cell transfer from donors which possessed hyperdiploid Ly-1+ B cells. (NZB x DBA/2)F1 recipients of NZB spleen cells demonstrated a 10- to 1000-fold increase in Ly-1+ B cells in the spleen but showed no increased levels of Ly-1+ B cells in the peritoneum. Nearly all the splenic Ly-1+ B cells were hyperdiploid with the phenotype of the NZB parent. Cytogenetic analysis revealed that all the hyperdiploid cells were NZB donor cells. These findings suggest that the increase in splenic Ly-1+ B cells in the F1 recipients was due to expansion of injected splenic hyperdiploid Ly-1+ B cells of NZB origin. All of the F1 recipients of NZB hyperdiploid Ly-1+ B cells demonstrated a significant decrease in endogenous B cells as well as decreased serum IgM and anti-ssDNA autoantibodies. These studies suggest that hyperdiploid Ly-1+ B cells are different from typical peritoneal Ly-1+ B cells both in the lymphoid organs to which they home and in their proliferative capacity. NZB hyperdiploid Ly-1+ B cells, which may arise as a natural consequence of hyperactive Ly-1+ B cells, may play an immunoregulatory role in the spleen.

Intersecting Stigma and the HIV Care Cascade: Qualitative Insights from Sex Workers, Men who have Sex with Men, and Transgender Women Living with HIV in Jamaica

In Jamaica, stigma experiences of sex workers (SW), gay men and other men who have sex with men (MSM), and transgender women living with HIV remain understudied. To address this gap, we explored experiences of stigma and linkages with the HIV care cascade among key populations living with HIV in Jamaica, including cisgender women SW, MSM, and transgender women. This qualitative study involved n = 9 focus groups (FG), n = 1 FG per population living with HIV (SW, MSM, transgender women) in each of three sites (Kingston, St. Ann, Montego Bay). We also conducted key informant (KI) interviews. We applied thematic analysis informed by the Health Stigma and Discrimination (HSD) Framework. FG participants (n = 67) included SW (n = 18), MSM (n = 28), and trans women (n = 21); we interviewed n = 10 KI (n = 5 cisgender women, n = 5 cisgender men). Participant discussions revealed that stigma drivers included low HIV treatment literacy, notably misinformation about antiretroviral therapy (ART) benefits and HIV acquisition risks, and a lack of legal protection from discrimination. Stigma targets health (HIV) and intersecting social identities (sex work, LGBTQ identities, gender non-conformity, low socio-economic status). Stigma manifestations included enacted stigma in communities and families, and internalized stigma-including lateral violence. HIV care cascade impacts included reduced and/or delayed HIV care engagement and ART adherence challenges/disruptions. Participants discussed strategies to live positively with HIV, including ART adherence as stigma resistance; social support and solidarity; and accessing affirming institutional support. In addition to addressing intersecting stigma, future research and programing should bolster multi-level stigma-resistance strategies to live positively with HIV.

343 RIGHT CARE, RIGHT PLACE, RIGHT TIME? WHAT PROPORTION OF ACUTELY-UNWELL OLDER PATIENTS UNDERGO EVIDENCE-BASED COMPREHENSIVE GERIATRIC ASSESSMENT?

Background

There is robust evidence that Comprehensive Geriatric Assessment (CGA) improves outcomes for acutely unwell older people. Relatively little research has examined how this translates to real life clinical settings, however. The aim of this study therefore was to ascertain how many older people admitted to hospital underwent CGA and how this impacted on readmission rates.

Methods

The study site is a large teaching hospital with 150 specialist geriatric medicine beds and ‘specialty-take’ of frail, older people by the geriatric medicine service. Data pertaining to contact with a geriatric medicine service were collected for 400 consecutive ED presentations of patients aged ≥70 years from 1/1/21, as well as Clinical Frailty Scale (CFS) and readmission within 30 days.

Results

Over one-third (139/400, mean CFS 3.7) of patients were discharged home directly from the ED, with the remainder (261/400, mean CFS 4.5) admitted to hospital. Almost-half overall (122/261, mean CFS 4.7) and 58% of those ≥80 years, were admitted under the care of a geriatrician, with 73% (89/122) cared for on a specialist geriatric medicine ward. Of those not admitted under a geriatrician, 10% (13/139) subsequently underwent CGA on a consultation basis. In total, 48% (126/261, mean CFS 3.7) of patients ≥70 years, including one-third of those ≥80 years with a CFS≥5 (36/99), completed their admission without undergoing CGA. Of those ≥80 years with a CFS≥5 who did not receive CGA, readmission within 30 days was 24% compared to 13% for those who underwent CGA.

Conclusion

Patients who underwent CGA were older, with higher levels of frailty. However, one-third of those aged ≥80 years with CFS ≥5 did not undergo CGA and early readmission was higher in this cohort. CGA in the acute setting is a finite resource and it is imperative it is delivered to those who require it most.