A temporal extracellular transcriptome atlas of human pre-implantation development

Non-invasively evaluating gene expression products in human pre-implantation embryos remains a significant challenge. Here, we develop a non-invasive method for comprehensive characterization of the extracellular RNAs (exRNAs) in a single droplet of spent media that was used to culture human in vitro fertilization embryos. We generate the temporal extracellular transcriptome atlas (TETA) of human pre-implantation development. TETA consists of 245 exRNA sequencing datasets for five developmental stages. These data reveal approximately 4,000 exRNAs at each stage. The exRNAs of the developmentally arrested embryos are enriched with the genes involved in negative regulation of the cell cycle, revealing an exRNA signature of developmental arrest. Furthermore, a machine-learning model can approximate the morphology-based rating of embryo quality based on the exRNA levels. These data reveal the widespread presence of coding gene-derived exRNAs at every stage of human pre-implantation development, and these exRNAs provide rich information on the physiology of the embryo.

Social Frailty and Executive Function: Association with Geriatric Syndromes, Life Space and Quality of Life in Healthy Community-Dwelling Older Adults

BACKGROUND

Despite emerging evidence about the association between social frailty and cognitive impairment, little is known about the role of executive function in this interplay, and whether the co-existence of social frailty and cognitive impairment predisposes to adverse health outcomes in healthy community-dwelling older adults.

OBJECTIVES

We aim to examine independent associations between social frailty with the MMSE and FAB, and to determine if having both social frailty and cognitive impairment is associated with worse health outcomes than either or neither condition.

METHODS

We studied 229 cognitively intact and functionally independent community-dwelling older adults (mean age= 67.2±7.43). Outcome measures comprise physical activity; physical performance and frailty; geriatric syndromes; life space and quality of life. We compared Chinese Mini Mental State Examination (CMMSE) and Chinese Frontal Assessment Battery (FAB) scores across the socially non-frail, socially pre-frail and socially frail. Participants were further recategorized into three subgroups (neither, either or both) based on presence of social frailty and cognitive impairment. Cognitive impairment was defined as a score below the educational adjusted cut-offs in either CMMSE or FAB. We performed logistic regression adjusted for significant covariates and mood to examine association with outcomes across the three subgroups.

RESULTS

Compared with CMMSE, Chinese FAB scores significantly decreased across the social frailty spectrum (p<0.001), suggesting strong association between executive function with social frailty. We derived three subgroups relative to relationship with socially frailty and executive dysfunction: (i) Neither, N=140(61.1%), (ii) Either, N=79(34.5%), and (iii) Both, N=10(4.4%). Compared with neither or either subgroups, having both social frailty and executive dysfunction was associated with anorexia (OR=4.79, 95% CI= 1.04-22.02), near falls and falls (OR= 5.23, 95% CI= 1.10-24.90), lower life-space mobility (odds ratio, OR=9.80, 95% CI=2.07-46.31) and poorer quality of life (OR= 13.2, 95% CI= 2.38-73.4).

CONCLUSION

Our results explicated the association of executive dysfunction with social frailty, and their synergistic relationship independent of mood with geriatric syndromes, decreased life space and poorer quality of life. In light of the current COVID-19 pandemic, the association between social frailty and executive dysfunction merits further study as a possible target for early intervention in relatively healthy older adults.

Grip Strength Criterion Matters: Impact of Average Versus Maximum Handgrip Strength on Sarcopenia Prevalence and Predictive Validity for Low Physical Performance

IMPORTANCE

Muscle strength has been elevated to the forefront of sarcopenia diagnosis, with handgrip strength the preferred measure. Extant handgrip protocols adopt different handgrip strength (HGS) criteria. Paucity of direct comparison studies assessing the impact of HGS criterion on prevalence of sarcopenia and predictive validity on physical performance contributes to the lack of standardisation of HGS criteria in sarcopenia diagnosis.

OBJECTIVES

Our study aims to compare the effect of average (HGSave) versus maximum (HGSmax) HGS criterion on: (1) prevalence of low HGS and sarcopenia; and (2) association with physical performance at baseline and at 2 years.

METHODS

We recruited 200 community dwelling, cognitively intact, and functionally independent older adults. Muscle strength, physical performance measures, cognitive tests and nutritional assessments were performed. Short Physical Performance Battery (SPPB) was administered at baseline and at 2 years. We compared HGSave and HGSmax to assess the prevalence of low HGS and sarcopenia. Univariate analysis was performed comparing baseline characteristics between low and normal groups for each HGS criterion. Significantly different variables were included in logistic regression analysis to examine association of low HGS and SPPB at baseline. Predictive validity of low HGS for SPPB<10 at 2 years was examined by performing logistic regression analysis for HGSave and HGSmax.

RESULTS

The prevalence of low HGS and sarcopenia incorporating HGSave criterion is 40% and 33% respectively, whereas that of HGSmax criterion is 21% and 19.5% respectively. There is moderate agreement between the 2 HGS criteria for sarcopenia diagnosis (kappa=0.604) and poorer agreement for low HGS (kappa=0.570). There was no significant association with baseline SPPB for both HGS criteria. At 2 years, only low HGSmax was significantly associated with low SPPB (adjusted OR 3.91, 95% CI 1.24 - 12.33).

CONCLUSION

Our study demonstrates that HGS criteria matters in diagnosis of sarcopenia and we support extant HGS protocols using HGSmax criterion in view of better predictive validity for poor physical performance.

Disentangling the Relationship between Frailty and Intrinsic Capacity in Healthy Community-Dwelling Older Adults: A Cluster Analysis

BACKGROUND

Frailty and intrinsic capacity (IC) are distinct but interrelated constructs. Uncertainty remains regarding how they are related and interact to influence health outcomes. We aim to understand the relationship between frailty and IC by identifying subgroups based on frailty criteria and IC domains and studying one-year outcomes.

METHODS

We studied 200 independent community-dwelling older adults (mean age 67.9±7.9 years, Modified Barthel Index (MBI) score 99±2.6). Frailty was defined by modified Fried criteria. Scores (range: 0-2) were assigned to individual IC domains (cognition, psychological, locomotion, and vitality) to yield a total IC score of 8. To identify subgroups, two-step cluster analysis was performed with age, frailty and IC domains. Cluster associations with one-year outcomes (frailty, muscle strength (grip strength, repeated chair stand test), physical performance (gait speed, Short Physical Performance Battery), function (MBI) and quality-of-life (EuroQol (EQ)-5D)) were examined using multiple linear regression adjusted for age, gender and education.

RESULTS

Three distinct clusters were identified - Cluster 1: High IC/Robust (N=74, 37%); Cluster 2: Intermediate IC/Prefrail (N=73, 36.5%); and Cluster 3: Low IC/Prefrail-Frail (53, 26.5%). Comparing between clusters, IC domains, cognition, depressive symptoms, nutrition, strength and physical performance were least impaired in Cluster 1, intermediate in Cluster 2 and most impaired in Cluster 3. At one year, the proportion transitioning to frailty or remaining frail was highest in Cluster 3 compared to Cluster 2 and Cluster 1 (39% vs 6.9% vs 2.8%, P<0.001). Compared to Cluster 1, Cluster 3 experienced greatest declines in grip strength (β=-4.1, P<.001), MBI (β=-1.24, P=0.045) and EQ-5D utility scores (β=-0.053, P=0.005), with Cluster 2 intermediate between Cluster 1 and Cluster 3.

CONCLUSIONS

Amongst independent community-dwelling older adults, IC is complementary to frailty measures through better risk-profiling of one-year outcomes amongst prefrail individuals into intermediate and high-risk groups. The intermediate group merits follow-up to ascertain longer-term prognosis.

Roadmap Out of COVID-19

The recent coronavirus disease (COVID-19) was declared as a public health emergency by the World Health Organisation on 30th January 2020, and has now affected more than 100 countries. Healthcare institutions and governments worldwide have raced to contain the disease, albeit to varying degrees of success. Containment strategies adopted range from complete lockdowns to remaining open with public advisories regarding social distancing. However, general principles adopted by most countries remain the same, mainly to avoid gatherings in large numbers and limit social interactions to curb the spread of disease. In Singapore, this disease had a very different progression. The first wave of the disease started with the confirmation of the first COVID-19 positive patient in Singapore on 23rd January 2020. Initially, the daily number of confirmed cases were low and manageable. With a rise in unlinked cases, the Disease Outbreak Response System Condition (DORSCON) status was raised from yellow to orange. New cluster outbreaks in foreign worker dormitories led to the rampant spread of disease, with daily spikes of COVID-19 cases. As of 7th June 2020, we have a total of 37,910 confirmed cases of COVID-19 infections, the highest in Southeast Asia, 12,999 active cases and a manageable mortality count of 25 deaths. This details our unique method for dealing with a pandemic, including a brief demographic of trauma patients during this period. We were able to conserve sufficient resources to ensure that our essential services can still continue. Moving on, we have to ensure the continued protection of our population, especially the vulnerable groups such as the elderly and the immunocompromised, as we reopen.

Characterization and in vitro evaluation of a vaginal gel containing Lactobacillus crispatus for the prevention of gonorrhea

The increasing resistance of Neisseria gonorrhoeae to any current antibiotic treatment and the difficulties associated with the use of prevention means such as condom urge the need for alternative methods to prevent this sexually transmitted infection. In this work, a prevention strategy based on the use of a vaginal gel containing Lactobacilli was assessed in vitro. A Lactobacillus crispatus strain (ATCC 33197) was selected based on the published data on its ability to inhibit Neisseria gonorrhoeae. Its probiotic properties were first characterized. Then, a thermo-sensitive hydrogel containing 21.5% of poloxamer 407, 1% of sodium alginate and 9log₁₀ CFU of Lactobacillus crispatus per gel sample (5 g) was developed. The gelation temperature and the rheological characteristics of this formulation appeared suitable for a vaginal administration. Lactobacillus crispatus was viable in the gel for six months although a large amount of the bacteria was not culturable. The ability of Lactobacillus crispatus to inhibit Neisseria gonorrhoeae was still observed with the gel. Such system, thus, appeared promising for the prevention of gonorrhea.

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.

THU0410 COMPANION IMMUNOSUPPRESSION WITH AZATHIOPRINE INCREASES THE FREQUENCY OF PERSISTENT RESPONSIVENESS TO PEGLOTICASE IN PATIENTS WITH CHRONIC REFRACTORY GOUT

Background:

Pegloticase is a mammalian recombinant uricase coupled to monomethoxy polyethylene glycol that is approved in the US for treatment of patients with chronic refractory gout and causes profound reductions in serum urate. However, treatment with pegloticase is limited by the induction of anti-drug antibodies and loss of responsiveness in nearly half of treated patients.

Objectives:

The goal of this study was to determine whether co-therapy with azathioprine (AZA) would increase the frequency of chronic refractory gout patients who had persistent urate lowering from pegloticase therapy.

Methods:

This open label multicenter study enrolled subjects with chronic gout who failed to lower serum urate to <6 mg/dL despite medically indicated doses of urate lowering therapy (NCT02598596). Patients were screened for adequate levels of the AZA metabolizing enzyme thiopurine methyl transferase and then started on daily oral AZA 1.25 mg/kg for 1 week and then 2.5 mg/kg for the remainder of the trial. Blood levels of AZA metabolites 6-thioguanine and 6-methylmercaptopurine were measured biweekly. After receiving 2 weeks of AZA, patients were started on pegloticase (8 mg IV) and were treated biweekly for 24 weeks. The primary endpoint was the persistent lowering of serum urate to <6 mg/dL at the last three consecutive study visits. Patients who had an increase in serum urate to >6 mg/dL while on therapy did not receive additional pegloticase. All patients received infusion prophylaxis with hydrocortisone as well as gout flare prophylaxis.

Results:

To date, 12 patients have been enrolled. All patients were male, 75% white and 25% African American. Mean age was 62.4 ± 14.7 years, the mean BMI was 31.1 ± 4.5 and the mean duration of gout was 13.8 ± 9.2 years. At baseline, all patients had visible tophi; 58.3% suffered from gout flares; 81.8% had hypertension; 45.5% had dyslipidemia and 9.0% had coronary artery disease. Of the 12 patients, 6 have completed the full course of treatment with persistent urate lowering and 2 remain on treatment also with persistent urate lowering (figure). 2 patients lost the urate lowering effect, both after 2 doses of pegloticase, and did not receive additional therapy. 1 patient experienced an infusion reaction during the first dose (1 infusion reaction in 90 infusions [1.1%] in the entire trial to date) and 1 subject had subjective symptoms of AZA intolerance with no laboratory abnormalities; these subjects discontinued the study and were not evaluable for the endpoint. No adverse events related to AZA were reported and gout flares were noted in 6 subjects (mean 1.5 flares/patient with flares).

Conclusion:

AZA can be used safely in subjects with chronic refractory gout and appears to increase the frequency of subjects experiencing long term lowering of serum urate.

References:

Disclosure of Interests: :

Hope Rainey: None declared, Herbert S.B. Baraf Grant/research support from: Horizon; Gilead Sciences, Inc.; Pfizer; Janssen; AbbVie, Consultant of: Horizon; Gilead Sciences, Inc.; Merck; AbbVie, Speakers bureau: Horizon, Anthony Yeo Employee of: Horizon, Peter Lipsky Consultant of: Horizon Therapeutics

THU0433 TREATMENT WITH PEGLOTICASE IMPROVES HEPATIC FIBROSIS ESTIMATED BY FIBROSIS-4 INDEX IN SUBJECTS WITH CHRONIC REFRACTORY GOUT

Background:

Hyperuricemia is associated with non-alcoholic fatty liver disease (NAFLD)1,2, but the relationship to fibrosis remains uncertain3. Moreover, it is not known whether lowering serum urate will affect the course of NAFLD. The availability of data from two randomized trials of pegloticase, a pegylated recombinant mammalian uricase, that profoundly decreases serum urate afforded the opportunity to test the hypothesis that lowering urate might improve NAFLD.

Objectives:

To determine whether treatment of chronic refractory gout patients with pegloticase was associated with improvement in NAFLD determined by Fibrosis 4 index (Fib4).

Methods:

Databases from patients with chronic refractory gout who participated in two randomized 6 month clinical trials (RCTs) of pegloticase were analyzed4. Sub-sets who had persistent urate lowering to levels <1 mg/dL in response to biweekly pegloticase (Responders, n=36) were compared to those who received placebo (n=43). Since liver biopsy information was not available on these subjects, we relied on Fib4, a validated non-invasive estimate of liver fibrosis in a variety of liver diseases5,6calculated from measurements of AST, ALT, platelet count and age (Age x AST/platelets x √ALT). A Fib4 value of 1.3 is an indication that further evaluation of liver disease is warranted.

Results:

At baseline, the mean Fib4 values were 1.40 ± 0.86 in pegloticase responders and 1.04 ± 0.53 in subjects receiving placebo. As shown in figure 1, subjects receiving placebo exhibited a change of 0.26 ± 0.41 in the Fib4 score over the six months of the RCTs compared with 0.13 ± 0.62 in the pegloticase responders (p=0.048; by linear regression). When only the subjects with a Fib4 value > 1.3 were considered, a significant difference in the change in the Fib4 values over the 6 months of the trial between pegloticase responders and those receiving placebo was also observed (-0.15 ± 0.67 vs 0.37 ± 0.42, p=0.004, by linear regression). The correlations between serum urate area under the curve (AUC) over the 6 months of the trial and the change in Fib4 value was rs=0.33, p=0.0.0004 (Spearman rank-order correlation coefficient). Finally, multiple linear regression analysis indicated serum urate AUC (as a surrogate measure for group) is the main contributor to the change in Fib4 (p=0.018 by linear regression).

Conclusion:

The data are consistent with the conclusion that persistent lowering of serum urate had a significant impact on Fib4 levels, implying a possible effect on the course of NAFLD. The results support a more complete analysis involving biopsy examination of the impact of urate on liver inflammation and fibrosis.

References:

[1]Yang C et al. PlosOne2017; 12:e0177249

[2]Jaruvongvanich V et al. Eur J Gastroenterol Hepatol 2017; 29:1031

[3]Jaruvongvanich V et al. Eur J Gastroenterol Hepatol 2017; 29:694

[4]Sundy JS, et al. JAMA. 2011; 306 (7):711-20

[5]Sterling RK et al. Hepatol 2006; 43:1317

[6]Shah AG et al. Clin Gastroenterol Hepatol 2009;7:1104

Disclosure of Interests: :

Naomi Schlesinger Grant/research support from: Pfizer, Amgen, Consultant of: Novartis, Horizon Therapeutics, Selecta Biosciences, Olatec, IFM Therapeutics, Mallinckrodt Pharmaceuticals, Anthony Yeo Employee of: Horizon Therapeutics, Peter Lipsky Consultant of: Horizon Therapeutics

Obesity Definitions in Sarcopenic Obesity: Differences in Prevalence, Agreement and Association with Muscle Function

BACKGROUND

Sarcopenic obesity (SO) is associated with poorer physical performance in the elderly and will increase in relevance with population ageing and the obesity epidemic. The lack of a consensus definition for SO has resulted in variability in its reported prevalence, poor inter-definitional agreement, and disagreement on its impact on physical performance, impeding further development in the field. While sarcopenia definitions have been compared, the impact of obesity definitions in SO has been less well-studied.

OBJECTIVES

To compare 3 widely-adopted definitions of obesity in terms of SO prevalence, inter-definitional agreement, and association with muscle function.

DESIGN

Cross-sectional.

SETTING

GERILABS study, Singapore Participants: 200 community-dwelling, functionally-independent older adults.

MEASUREMENTS

We utilized three commonly-used definitions of obesity: body mass index (BMI), waist circumference (WC) and DXA-derived fat mass percentage (FM%). Sarcopenia was defined using Asian Working Group for Sarcopenia criteria. For muscle function, we assessed handgrip strength, gait speed and Short Physical Performance Battery (SPPB). Subjects were classified into 4 body composition phenotypes (normal, obese, sarcopenic and SO), and outcomes were compared between groups.

RESULTS

The prevalence rate for SO was lowest for BMI (0.5%) compared to FM% (10.0%) and WC (10.5%). Inter-definitional agreement was lowest between BMI and WC (κ=0.364), and at best moderate between FM% and WC (κ=0.583). SO performed the worst amongst body composition phenotypes in handgrip strength, gait speed and SPPB (all p<0.01) only when defined using WC. In regression analyses, SO was associated with decreased SPPB scores (β=-0.261, p=0.001) only for the WC definition.

CONCLUSION

There is large variation in the prevalence of SO across different obesity definitions, with low-to-moderate agreement between them. Our results corroborate recent evidence that WC, and thus central obesity, is best associated with poorer muscle function in SO. Thus, WC should be further explored in defining obesity for accurate and early characterization of SO among older adults in Asian populations.

Muscle Strength Definitions Matter: Prevalence of Sarcopenia and Predictive Validity for Adverse Outcomes Using the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) Criteria

BACKGROUND

EWGSOP2 criteria for sarcopenia recommends the use of either handgrip strength (GS) or 5-times repeated chair stand test (RCS) as a muscle strength measure. We aim to compare the impact of different muscle strength definitions on sarcopenia prevalence and predictive validity for 2-year outcomes, using the EWGSOP2 clinical algorithm.

METHODS

We studied 200 community-dwelling older adults, comparing sarcopenia prevalence using three muscle strength definitions: 1) maximum GS (Asian Working Group cutoffs); 2) RCS-1 (standard cutoff >15s); and 3) RCS-2 (ROC-derived cutoff >12.5s). Two-year outcomes include: 1) Incident frailty (modified Fried criteria); 2) Physical performance [Short Physical Performance Battery (SPPB) score <10]; and 3) Quality of life [EuroQol-5 dimension (EQ-5D) <25th percentile]. We performed logistic regression on 2-year outcomes adjusted for age, gender, cognition and mood.

RESULTS

Prevalence of confirmed sarcopenia was 14.5%, 4% and 9% for GS, RCS-1 and RCS-2 respectively. For 2-year outcomes (N=183), RCS-2 predicted incident frailty (OR: 5.7, 95% CI 1.4-22.8, p=0.013), low SPPB (OR: 4.4, 95% CI 1.4-13.1, p=0.009), and trended towards predicting low QOL (OR: 2.1, 95% CI 0.9-4.9, p=0.095). In contrast, GS and RCS-1 did not predict frailty nor low QOL, but predicted low SPPB only (GS: OR 3.8, 95% CI 1.3-10.6, p=0.01; RCS-1: OR: 8.8, 95% CI 2.2-35.0, p=0.002).

CONCLUSIONS

Sarcopenia prevalence varies with muscle strength definitions, with GS being significantly higher vis-à-vis RCS definitions. Our results also support the use of population-specific over standard cutoffs for RCS to obtain intermediate estimates of sarcopenia prevalence and the best predictive validity for two-year outcomes.

The challenge of differentiating vaso-occlusive crises from osteomyelitis in children with sickle cell disease and bone pain: A 15-year retrospective review

PURPOSE

The paediatric sickle cell disease (SCD) osteomyelitis (OM) incidence is 0.3% to 12%. Differentiating vaso-occlusive crises (VOC) from OM is a diagnostic challenge, with limited evidence guiding management. We present a 15-year review of a paediatric sickle cell cohort. We aim to identify OM incidence and provide a management protocol for these children presenting with bone pain.

METHODS

A prospective database of children with haemoglobinopathies (2002 to 2017) was analyzed for temperature, C-reactive protein (CRP) and white cell count (WCC) on admission as well as imaging, treatment and cultures. OM diagnosis was supported by imaging and blood cultures. VOC was defined as bone pain that improved without antibiotics.

RESULTS

Over 15 years, 96 children with SCD presented 358 times to hospital. Empirical antibiotics were given in 308 presentations. There were five cases of OM (1.4%); two acute and three chronic. In all, 50 presentations of VOC were identified. No significant differences in age were noted between the OM and VOC group. Temperature and CRP were significantly elevated in the OM group with no significant difference in WCC. Cultures were only positive in the chronic OM admissions. There were no cases of septic arthritis. No surgical intervention was required.

CONCLUSION

In children with SCD presenting with persistent bone pain, fever, elevated CRP and WCC, OM should be suspected and prompt antibiotic treatment started. Our treatment pathway was successful avoiding OM in 98.6% and septic arthritis in 100%. Further research on novel biological markers distinguishing OM from VOC should be investigated.

LEVEL OF EVIDENCE

III.

Serum Myostatin and IGF-1 as Gender-Specific Biomarkers of Frailty and Low Muscle Mass in Community-Dwelling Older Adults

OBJECTIVES

(i) To investigate serum myostatin (absolute and normalized for total body lean mass (TBLM)) and IGF-1 as biomarkers of frailty and low relative appendicular skeletal muscle mass (RASM) in older adults, and; (ii) to examine gender differences in the association of serum myostatin and IGF-1 levels with frailty and low RASM.

DESIGN

Cross-sectional study.

SETTING

The "Longitudinal Assessment of Biomarkers for characterization of early Sarcopenia and predicting frailty and functional decline in community-dwelling Asian older adults Study" (GERI-LABS) study in Singapore.

PARTICIPANTS

200 subjects aged 50 years and older residing in the community.

MEASUREMENTS

Frailty was assessed using the modified Fried criteria. Low RASM was defined using cutoffs for height-adjusted appendicular skeletal muscle mass measured by dual-energy X-ray absorptiometry as recommended by the Asian Working Group for Sarcopenia. Comorbidities, cognitive and functional performance, physical activity and nutritional status were assessed. Blood samples collected included serum myostatin, insulin-like growth factor 1 (IGF-1) and markers of inflammation (total white cell count, CRP, IL-6 and TNFaR1). Subjects were classified into 4 groups: Frail/Prefrail with low RASM (Frail/Low RASM), Frail/Prefrail with normal RASM (Frail/Normal RASM), Robust with low RASM (Robust/Low RASM) and Robust with normal RASM (Robust/Normal RASM).

RESULTS

63 (32%) subjects were classified as Frail/Low RASM, 53 (27%) Frail/Normal RASM, 28 (14%) Robust/Low RASM and 56 (28%) Robust/Normal RASM respectively. Frail/Low RASM subjects were older and had lower BMI compared to Frail/Normal RASM and robust subjects. Mean (SE) normalized myostatin levels were higher in Frail/Low RASM compared to Frail/Normal RASM subjects (1.0 (0.04) versus 0.84 (0.05) ng/ml/kg, P=0.01). Median (IQR) IGF-1 level was lower amongst Frail/Low RASM subjects compared to Frail/Normal RASM subjects (102.3, (77.7, 102.5) vs 119.7 (82.7, 146.0) ng/ml, P=0.046). No differences in myostatin or IGF-1 were observed among robust individuals with or without low muscle mass. In adjusted multinomial logistic regression models with Robust/Normal RASM as the reference group, myostatin (P=0.05) and IGF-1 (P=0.043) were associated with Frail/Low RASM status in the whole cohort. When stratified by gender, myostatin was significantly associated with Frail/Low RASM status in men only (P=0.03). In women, serum IGF-1 was associated with Frail/Low RASM status (P=0.046), but not myostatin (P=0.53).

CONCLUSION

Serum myostatin, normalized for TBLM in men and IGF-1 in women are potential biomarkers for frail individuals with low RASM, and may identify a target group for intervention.

BOS is associated with decreased HDAC2 from steroid resistant lymphocytes in the small airways

Immunosuppression therapies including corticosteroids fail to prevent bronchiolitis obliterans syndrome (BOS), primarily a disease of the small airways, following lung transplantation. We reported increases in steroid-resistant proinflammatory lymphocytes and their loss of histone deacetylase 2 (HDAC2), an important mediator of steroid action, in the blood of stable lung transplant recipients. We noted similar increases in the steroid-resistant lymphocytes in both the blood and small airways in BOS compared with the large airways. We hypothesized that these small airway cells would also exhibit a loss of HDAC2, and that these changes could be reversed by treatment with theophylline (HDAC2 activator). Blood, bronchoalveolar lavage and large and small airway brushings were collected from lung transplant patients with BOS (n = 12) or stable lung function (n = 18) and healthy aged-matched controls (n = 13). Intracellular proinflammatory cytokines [interferon (IFN-γ) and tumour necrosis factor (TNF)-α and HDAC2 were measured in CD8⁺ T, natural killer (NK) T-like and NK cells from cultured small airway brushings ± 5 mg/l theophylline ± 1 µM prednisolone using flow cytometry. Increased small airway CD8 T, NK T-like and NK cells were identified in BOS versus stable transplant and controls. In BOS, these cells exhibited increased IFN-γ/TNF-α and a loss of HDAC2. HDAC2 expression by small airway CD8⁺ T cells correlated with forced expiratory volume in 1 s (FEV₁ ) (R = 0·880, P = 0·031). Theophylline and prednisolone synergistically up-regulated HDAC2 in CD8⁺ T cells. BOS is associated with loss of HDAC2 from steroid-resistant proinflammatory CD8⁺ T, NK T-like and NK cells in the small airways. Therapeutically increasing HDAC2 in these lymphocytes may reduce steroid resistance and improve graft survival.

Bronchiolitis obliterans syndrome is associated with increased p-glycoprotein expression and loss of glucocorticoid receptor from steroid-resistant proinflammatory CD8+ T cells

Immunosuppressive therapy fails to suppress the production of proinflammatory cytokines, particularly by CD8+ T cells, in stable lung transplant recipients and those undergoing chronic rejection, suggesting that some patients may become relatively resistant to immunosuppressants such as glucocorticoids (GC). We have shown loss of GC receptor (GCR) from the CD8+ cells, and we hypothesized that the drug membrane efflux pump, p-glycoprotein-1 (Pgp), may also be involved in lymphocyte steroid resistance following lung transplant. Pgp/GCR expression and interferon (IFN)-γ/tumour necrosis factor (TNF)-α proinflammatory cytokine production was measured in blood lymphocytes from 15 stable lung transplant patients, 10 patients with bronchiolitis obliterans syndrome (BOS) and 10 healthy aged-matched controls (± prednisolone ± Pgp inhibitor, cyclosporin A ± GCR activator, Compound A) using flow cytometry. Both Pgp+ and Pgp- lymphocyte subsets from all subjects produced IFN-γ/TNF-α proinflammatory cytokines. Pgp expression was increased in CD8+ Pgp+ T cells and correlated with IFN-γ/TNF-α expression and BOS grade. Reduced GCR was observed in CD8+ Pgp- T, natural killer (NK) T-like and NK cells from stable patients compared with controls, and reduced further in CD8+ Pgp- T cells in BOS. The addition of 2·5 ng/ml cyclosporin A and 1 µM prednisolone inhibit IFN-γ/TNF-α production significantly by CD8+ Pgp+ T cells from BOS patients. The addition of 10 µM Compound A and 1 µM prednisolone inhibit IFN-γ/TNF-α production significantly by CD8+ Pgp- T cells from BOS patients. BOS is associated with increased Pgp expression and loss of GCR from steroid-resistant proinflammatory CD8+ T cells. Treatments that inhibit Pgp and up-regulate GCR in CD8+ T cells may improve graft survival.

Clavicle fracture nonunion in the paediatric population: a systematic review of the literature

AIMS

Clavicle fracture nonunions are extremely rare in children. The aim of this systematic review was to assess what factors may predispose children to form clavicle fracture nonunions and evaluate the treatment methods and outcomes.

METHODS

We performed a systematic review according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, aiming to find papers reporting clavicle fracture nonunion in children under the age of 18 years. Data was collected on patient demographics, fracture type, mechanism of injury (MOI), surgical intervention and reported outcome. Two independent reviewers evaluated all the data.

RESULTS

A total of 13 articles reporting 21 cases of clavicle fracture nonunion were identified. The mean age at time of injury was 11.4 years (4 to 17). Falls were the most common MOI. The majority of nonunions occurred after displaced fractures on the right side. Six were refractures. Mean time of presentation following injury was 13.5 months (4 to 60). In all, 16 were treated surgically. Radiographic union was eventually achieved in 12 cases, with functional outcome satisfactory in all cases.

CONCLUSION

Clavicle nonunion is an extremely rare but possible complication in children. The majority occur after displaced right-sided fractures or refractures and present around one year after injury. Surgical fixation provides good radiographic healing and functional outcomes.

LEVEL OF EVIDENCE

IV.

Severely Injured Patients Presenting to the Singapore General Hospital: a one Year Study

Study objectives

To determine the quantity and resource utilisation in management of the severely injured patients presenting at the Singapore General Hospital (SGH).

Method

All patients who were initially triaged to the hospital Emergency Department's (ED) resuscitation room and all trauma related mortality in the year 1998 were studied. All records were traced and the cases were followed up. Important outcomes studied were mortality and length of hospital stay.

Results

Three hundred and forty-seven (0.2%) severely injured patients who were initially treated at the ED's resuscitation room were studied. The median age of the patients was 32 years old. Male patients formed 82.1% of the total. The three main causes of trauma in such patients were fall from height, motor vehicle related accidents and penetrating injuries caused by sharp instruments and firearms. Of all the patients, 62.8% were admitted to the ED between 1601 hours to 0759 hours and 30.5% of all severely injured patients were treated at the ED on weekends. One hundred and twenty three (35.4%) patients had emergency surgery within 24 hours of admission to the ED and 42.4% of the patients had an ISS score of 16 or more; 22.8% of patients had ISS score of 25 or more. The mortality of patients with ISS score of 25 or more was 39.2%.

Conclusion

One percent of all new ED patients with trauma were classified as ‘severely’ injured and these occurred mostly outside “normal working hours”. There was significant mortality in patients with ISS score of 25 or more.

A Clinical Audit to Assess the Efficacy of the Coolsense® Pain Numbing Applicator for Intravenous Cannulation in Children

The Coolsense® device is a topical applicator that is used to anaesthetise the skin before a painful procedure. It is a handheld device with a temperature-controlled head that acts on application, without chemicals, to cool and anaesthetise the site of injection. This prospective observational audit of 100 children and adolescents aged six to 18 years studied the analgesic efficacy and patient and carer satisfaction rating of the device during intravenous cannulation and complications arising from its use. The audit demonstrated effective skin analgesia for intravenous cannulation in children and adolescents. Ninety-four percent of patients rated the pain during cannulation as less than or equal to three on a numerical pain rating scale of zero to ten. Patient and carer satisfaction with the device and cannulation success rates were high; 66% of patients and 82% of carers ‘really liked’ the device and 28% of patients and 12% of carers ‘liked’ it. Ninety-five percent of patients were cannulated on the first attempt. The incidence of complications using the device was low. The Coolsense device appears to be a useful tool that provides effective analgesia for intravenous cannulation in children with minimal complications. Comparative studies with topical local anaesthesia creams are warranted.

Sex-specific differences in risk factors for sarcopenia amongst community-dwelling older adults

With considerable variation including potential sex-specific differential rate of skeletal muscle loss, identifying modifiable factors for sarcopenia will be pivotal to guide targeted interventions. This study seeks to identify clinical and biological correlates of sarcopenia in community-dwelling older adults, with emphasis on the role of anabolic and catabolic stimuli, and special reference to gender specificity. In this cross-sectional study involving 200 community-dwelling and functionally independent older adults aged ≥50 years, sarcopenia was defined using the Asian Working Group for Sarcopenia criteria. Comorbidities, cognitive and functional performance, physical activity and nutritional status were routinely assessed. Biochemical parameters included haematological indices, lipid panel, vitamin D level, anabolic hormones [insulin-like growth factor-1 (IGF-1), free testosterone (males only)] and catabolic markers [inflammatory markers (interleukin-6, C-reactive protein) and myostatin]. Multiple logistic regression was performed to identify independent predictors for sarcopenia. Age was associated with sarcopenia in both genders. Malnutrition conferred significantly higher odds for sarcopenia in women (OR = 5.71, 95% CI 1.13-28.84.44, p = 0.035) while higher but acceptable range serum triglyceride was protective in men (OR = 0.05, 95% CI 0.00-0.52, p = 0.012). Higher serum myostatin independently associated with higher odds for sarcopenia in men (OR = 1.11, 95% CI 1.00-1.24, p = 0.041). Serum IGF-1 was significantly lower amongst female sarcopenic subjects, with demonstrable trend for protective effect against sarcopenia in multiple regression models, such that each 1 ng/ml increase in IGF-1 was associated with 1% decline in odds of sarcopenia in women (p = 0.095). Our findings support differential pathophysiological mechanisms for sarcopenia that, if corroborated, may have clinical utility in guiding sex-specific targeted interventions for community-dwelling older adults.

Activation of HIF-1α (hypoxia inducible factor-1α) prevents dry eye-induced acinar cell death in the lacrimal gland

The pathogenesis of immune-mediated lacrimal gland (LG) dysfunction in Sjögren's syndrome has been thoroughly studied. However, the majority of dry eye (DE) is not related to Sjögren type, and its pathophysiology remains unclear. The purpose of this study was to determine and investigate the protective mechanisms against DE stress in mice. DE induced prominent blood vessel loss without apoptosis or necrosis in the LG. Autophagic vacuoles, distressed mitochondria, and stressed endoplasmic reticulum were observed via electron microscopy. Immunoblotting confirmed the increase in autophagic markers. Glycolytic activities were enhanced with increasing levels of succinate and malate that, in turn, activated hypoxia-inducible factor (HIF)-1α. Interestingly, the areas of stable HIF-1α expression overlapped with COX-2 and MMP-9 upregulation in LGs of DE-induced mice. We generated HIF-1α conditional knockout (CKO) mice in which HIF-1α expression was lost in the LG. Surprisingly, normal LG polarities and morphologies were completely lost with DE induction, and tremendous acinar cell apoptosis was observed. Similar to Sjögren's syndrome, CD3⁺ and CD11b⁺ cells infiltrated HIF-1α CKO LGs. Our results show that DE induced the expression of HIF-1α that activated autophagy signals to prevent further acinar cell damage and to maintain normal LG function.

The degradation profile of novel, bioresorbable PCL-TCP scaffolds: an in vitro and in vivo study

Degradation studies of scaffolds are important in bone tissue engineering. Previously, novel poly(epsilon-caprolactone)-20% tricalcium phosphate (PCL-TCP) based scaffolds were developed and proven useful for bone regeneration. In this study in vitro degradation analyses were carried out with the PCL-TCP scaffolds immersed in standard culture medium for 24 weeks. In vivo degradation was performed with the scaffolds implanted in the abdomen of rats for the same period of time. Results demonstrated greater degradation of PCL-TCP scaffolds in vivo than in vitro. At 24 weeks, the increase of average porosity of the scaffolds in vivo was 29.2% compared to 2.65% in vitro. Gel permeation chromatography (GPC) analysis revealed a decrease of 29% and 20% respectively in the Mn and Mw values after 24 weeks in vitro. However, a significant decrease in Mn and Mw values (79.6% and 88.7% respectively) were recorded in vivo. The mechanical properties however, were relatively similar and closely match those of cancellous bone even at 24 weeks. The results showed that the scaffold can be used for dentoalveolar reconstruction and PCL-TCP scaffolds have shown to possess the potential to degrade within the desired time period of 5-6 months and favorable mechanical properties.

Performance of individual fibers in a submerged hollow fiber bundle

Hollow fiber membranes are popular as they have a high specific membrane area. To take advantage of this, it is necessary to pack the fibers into closely packed bundles. The fibers in different positions in the bundle behave differently as they are exposed to different hydrodynamic conditions. In this paper, a 'model' bundle of 9 fibers was tested in a setup which provides flow measurement from individual fibers and the same suction pressure in each fiber. The parameters studied were packing density, cross flow velocity, feed concentration and bubbling. It was found that a low cross flow velocities, high pressures and high feed concentrations, the surrounded (center) fiber performed very poorly compared to the fibers at the corner and the sides. Under these conditions, the overall performance of the bundle was much worse that of a single fiber.

Association between a functional polymorphism in the serotonin transporter gene and diarrhoea predominant irritable bowel syndrome in women

BACKGROUND AND AIMS

Serotonin (5-hydroxtryptamine, 5-HT) is an important factor in gut function, playing key roles in intestinal peristalsis and secretion, and in sensory signalling in the brain-gut axis. Removal from its sites of action is mediated by a specific protein called the serotonin reuptake transporter (SERT or 5-HTT). Polymorphisms in the promoter region of the SERT gene have effects on transcriptional activity, resulting in altered 5-HT reuptake efficiency. It has been speculated that such functional polymorphisms may underlie disturbance in gut function in individuals suffering with disorders such as irritable bowel syndrome (IBS). The aim of this study was to assess the potential association between SERT polymorphisms and the diarrhoea predominant IBS (dIBS) phenotype.

SUBJECTS

A total of 194 North American Caucasian female dIBS patients and 448 female Caucasian controls were subjected to genotyping.

METHODS

Leucocyte DNA of all subjects was analysed by polymerase chain reaction based technologies for nine SERT polymorphisms, including the insertion/deletion polymorphism in the promoter (SERT-P) and the variable tandem repeat in intron 2. Statistical analysis was performed to assess association of any SERT polymorphism allele with the dIBS phenotype.

RESULTS

A strong genotypic association was observed between the SERT-P deletion/deletion genotype and the dIBS phenotype (p = 3.07x10(-5); n = 194). None of the other polymorphisms analysed was significantly associated with the presence of disease.

CONCLUSIONS

Significant association was observed between dIBS and the SERT-P deletion/deletion genotype, suggesting that the serotonin transporter is a potential candidate gene for dIBS in women.

Helical CT imaging of clinically suspected appendicitis: correlation of CT and histological findings

PURPOSE

The diagnosis of appendicitis is traditionally made on the basis of clinical findings supported by laboratory results. The aim of our study was to determine the accuracy and feasibility of using a relatively new technique of computed tomography (CT) using only colonic contrast medium.

MATERIALS AND METHODS

A total of 50 patients clinically diagnosed as having appendicitis were prospectively examined before surgery with thin-collimation helical CT from the L3 level to the acetabular roof with only rectally administered colon contrast medium. The hard copy CT images were reviewed jointly by two radiologists and a consensus was reached for each patient. The results were then compared with the surgical and histological findings at appendicectomy.

RESULTS

There were 35 true-positives, one false-positive, 12 true-negatives and two false-negatives for CT. This yielded an accuracy of 94%, sensitivity of 95%, specificity of 92%, positive predictive value of 97% and negative predictive value of 86%. The appendix was identified in 45 patients (90%) and obscured by an inflammatory mass in the remaining five. An alternative diagnosis was found in 10 of 12 normal CT examinations (83%).

CONCLUSION

Helical CT with rectal contrast medium is a quick, well tolerated and accurate test to diagnose appendicitis. It can offer alternative, possibly non-surgical diagnosis in patients who would otherwise have undergone laparotomy.

Breast abscess as the initial presentation of squamous cell carcinoma of the breast

Breast abscesses are common and rarely harbour an underlying malignancy. Antibiotics and drainage by aspiration are the mainstays of treatment. We encountered two post-menopausal patients aged 48 and 70 who presented with acute breast abscesses that had an underlying squamous cell carcinoma of the breast. Infective aetiology was considered in each case and pre-operative diagnosis is possible but requires a high level of suspicion to avoid a delay in diagnosis. Aspirate from the abscess should be sent for both culture and cytology and if drainage is done, then biopsy of the abscess cavity is essential. Clinicians should be aware of the association of this rare primary neoplasm of the breast.

Coincident signalling between the Gi/Go-coupled delta-opioid receptor and the Gq-coupled m3 muscarinic receptor at the level of intracellular free calcium in SH-SY5Y cells

In SH-SY5Y cells, activation of delta-opioid receptors with [D-Pen(2,5)]-enkephalin (DPDPE; 1 microM) did not alter the intracellular free Ca(2+) concentration [Ca(2+)](i). However, when DPDPE was applied during concomitant Gq-coupled m3 muscarinic receptor stimulation by carbachol or oxotremorine-M, it produced an elevation of [Ca(2+)](i). The DPDPE-evoked increase in [Ca(2+)](i) was abolished when the carbachol-sensitive intracellular Ca(2+) store was emptied. There was a marked difference between the concentration-response relationship for the elevation of [Ca(2+)](i) by carbachol (EC(50) 13 microM, Hill slope 1) and the concentration-response relationship for carbachol's permissive action in revealing the delta-opioid receptor-mediated elevation of [Ca(2+)] (EC(50) 0.7 mM; Hill slope 1.8). Sequestration of free G protein beta gamma dimers by transient transfection of cells with a beta gamma binding protein (residues 495-689 of the C terminal tail of G protein-coupled receptor kinase 2) reduced the ability of delta opioid receptor activation to elevate [Ca(2+)](i). However, DPDPE did not elevate either basal or oxotremorine-M-evoked inositol phosphate production indicating that delta-opioid receptor activation did not stimulate phospholipase C. Furthermore, delta-opioid receptor activation did not result in the reversal of muscarinic receptor desensitization, membrane hyperpolarization or stimulation of sphingosine kinase. There was no coincident signalling between the delta-opioid receptor and the lysophosphatidic acid receptor which couples to elevation of [Ca(2+)](i) in SH-SY5Y cells by a PLC-independent mechanism. In SH-SY5Y cells the coincident signalling between the endogenously expressed delta-opioid and m3 muscarinic receptors appears to occur in the receptor activation-Ca(2+) release signalling pathway at a step after the activation of phospholipase C.

Focused abdominal sonography for trauma (FAST)

This study aims to examine the feasibility of applying the focused ultrasound examination (FAST) in the initial assessment of the trauma patient. Its advantage over diagnostic peritoneal lavage lies in the speed in which it can be performed, its non-invasiveness and repeatability. Over the period January 1997 to July 1998, the FAST examination (Acuson 128XP/10, 3.5 MHz probe) was used to assess the presence of haemopericardium or haemoperitoneum in 38 multi-trauma patients admitted to the Singapore General Hospital. The sample comprises mainly males (82%) with a mean age of 34 years (range 17 to 77 years). The mechanism of injury was predominantly blunt (95%). Mean Injury Severity Score (ISS) was 22. Eleven patients presented in shock and 16 patients had abdominal tenderness on examination. A single surgeon did the examination, which was performed during the secondary survey phase of resuscitation. Time taken for the FAST examination averaged 2.3 +/- 1.3 minutes. The results of the examination were compared to diagnostic peritoneal lavage, CT scan, operative findings, serial examination and/or post-mortem findings. Overall sensitivity was 67% and specificity 97%. Although the FAST examination missed the small amount of free fluid seen in the CT scan of 2 patients, these patients did not have to undergo laparotomy as their abdominal examination was normal. We conclude that the FAST examination is feasible and should be part of a general surgeon's armamentarium in the initial assessment of trauma.

The gag domains required for avian retroviral RNA encapsidation determined by using two independent assays

The Rous sarcoma virus (RSV) Gag precursor polyprotein is the only viral protein which is necessary for specific packaging of genomic RNA. To map domains within Gag which are important for packaging, we constructed a series of Gag mutations in conjunction with a protease (PR) active-site point mutation in a full-length viral construct. We found that deletion of either the matrix (MA), the capsid (CA), or the protease (PR) domain did not abrogate packaging, although the MA domain is likely to be required for proper assembly. A previously characterized deletion of both Cys-His motifs in RSV nucleocapsid protein (NC) reduced both the efficiency of particle release and specific RNA packaging by 6- to 10-fold, consistent with previous observations that the NC Cys-His motifs played a role in assembly and RNA packaging. Most strikingly, when amino acid changes at Arg 549 and 551 immediately downstream of the distal NC Cys-His box were made, RNA packaging was reduced by more than 25-fold with no defect in particle release, demonstrating the importance of this basic amino acid region in packaging. We also used the yeast three-hybrid system to study avian retroviral RNA-Gag interactions. Using this assay, we found that the interactions of the minimal packaging region (Mpsi) with Gag are of high affinity and specificity. Using a number of Mpsi and Gag mutants, we have found a clear correlation between a reporter gene activation in a yeast three-hybrid binding system and an in vivo packaging assay. Our results showed that the binding assay provides a rapid genetic assay of both RNA and protein components for specific encapsidation.

A study of force and cross-sectional area of adductor pollicis muscle in female hip fracture patients

OBJECTIVES

To determine the extent of muscle weakness in older female hip fracture patients compared with healthy older and young women; to determine the extent to which this weakness is caused by a decline of the force produced per unit area of muscle rather than by a decline in muscle bulk; and to investigate the mechanism of the decline in force per unit area.

DESIGN

This was an open study of three groups of subjects, two age matched older groups and one young group.

SETTING

University College London, Royal Free Hospital, and St. Thomas's Hospital, London.

PARTICIPANTS

Twenty-nine older female hip fracture patients (mean age 85.6 +/- 0.9 SEM), 18 healthy older women (mean age 84.7 +/- 1.2 SEM), and 43 young women (mean age 28.9 +/- 1.2 SEM).

MEASUREMENTS

Adductor pollicis muscle maximum voluntary force (MVF) during isometric and pliometric contractions and cross-sectional area (CSA), body weight, height, and demi-span.

RESULTS

Isometric MVF was lowest in the hip fracture group. In both older groups, isometric MVF and CSA were lower than in the young women. Only part of this weakness in the older groups could be explained by the smaller CSAs. The isometric force per unit area (MVF/CSA) was also lower in both older groups, the hip fracture patients again having the lowest values. Analysis of variance showed a significant difference between groups. The age-related declines in pliometric force were much less than the declines in isometric force. This resulted in an increase in the pliometric/isometric force ratio both for the hip fracture patients and for the healthy older women compared with that for young women.

CONCLUSION

In comparison with the results from young women, the adductor pollicis muscles of female hip fracture patients were even weaker than those of healthy older women when normalized for muscle size. This decline in isometric MVF/CSA accounted for at least half of the overall weakness in the hip fracture patients. Inasmuch as pliometric force is maintained in situations where weakness is caused by a decline in the force produced per muscle cross-bridge, this is the likely mechanism of the declines in isometric MVF/CSA observed in this study.

A minimal avian retroviral packaging sequence has a complex structure

We have defined a 160-nucleotide region, Mpsi, from the 5' leader region of the Rous sarcoma virus genome that is sufficient to direct the packaging of a heterologous RNA. Mpsi contains the putative O3 stem structure that has previously been shown, and that has been confirmed in this study, to be important for the efficient packaging of avian leukosis-sarcoma virus RNA. Analyses of several O3 stem mutants revealed that other regions within Mpsi can interfere with the proper folding of altered sequences which are predicted to form a wild-type O3 stem.

Predictors of fetal mortality in pregnant trauma patients

BACKGROUND

Fetal mortality after trauma is significant. This study was aimed at identifying factors responsible for this high fetal mortality.

METHODS

All pregnant trauma patients admitted to the two major Toronto trauma institutions during the period of November of 1991 to February of 1996 with an Injury Severity Score (ISS) > or = 12 were assessed. Data on age, gestation, hypotension, ISS, hemoglobin, blood transfusion, length of stay, disseminated intravascular coagulation (DIC), and specific maternal injury were analyzed retrospectively to determine predictors of fetal mortality by comparison of patients with and without fetal survival.

RESULTS

Twenty of a total of 68 pregnant trauma patients qualified for entry into the trauma registry by having an ISS > or = 12. Overall fetal mortality was 65% (13 of 20) for ISS > or = 12, and there was one maternal death (age, 29 years; ISS, 66). There were no statistically significant differences between the fetal death and fetal survival groups in age (29.2 +/- 6.2 vs. 30.4 +/- 3.9 years), gestation (25.3 +/- 10.5 vs. 24.1 +/- 9.2 weeks), lowest systolic blood pressure (98.3 +/- 33.8 vs. 112 +/- 18.0 mm Hg), head injury rate (3 of 13 vs. 1 of 7), extremity injury rate (8 of 13 vs. 2 of 7), abdominal injury rate (4 of 13 vs. 0 of 7), pelvic fracture rate (6 of 13 vs. 1 of 7), and chest injury rate (5 of 13 vs. 3 of 7). However, ISS (27.7 +/- 3.5 vs. 14.2 +/- 11.4), lowest hemoglobin level (78.8 +/- 17.0 vs. 101.9 +/- 17.1), blood transfusions (10.8 +/- 6.3 vs. 0.9 +/- 1.6 units), length of stay (20.9 +/- 16.7 vs. 8.2 +/- 4.9 days), and the incidence of DIC (8 of 13 vs. 0 of 7) were statistically significantly different between the two groups (p < 0.05). All eight patients with abruptio placentae had associated fetal mortality.

CONCLUSIONS

Apart from ISS, blood loss, and abruptio placentae; the presence of DIC was the most significant predictor of fetal mortality. This finding may represent stimulation of DIC by placental products entering the maternal circulation after significant intrauterine injury.