[Efficacy of selective bronchial occlusion in the treatment of biliary bronchial fistula]

Objective: To analyze the effect of selective bronchial occlusion (SBO) in the treatment of biliary bronchial fistula (BBF). Methods: Eight patients with BBF that without biliary obstruction admitted to the Department of Respiratory and Critical Care Medicine, the First Affiliated Hospital of Naval Medical University from January 1, 2015 to December 31, 2021 were included in this study. Bronchial silicone plug (6 cases) and autologous blood+thrombin (2 cases) were used as sealing materials for SBO treatment for the first time. Among the 7 patients who underwent subsequent closure treatment, 5 cases were blocked by bronchial silicone plug, 1 case was blocked by "bronchial silicone plug+bullet-covered stent" and 1 case was blocked by "bronchial silicone plug+bronchial one-way valve". The clinical data related to SBO treatment were collected and patients were followed up, and the therapeutic effect of SBO on BBF was analyzed. Results: The age of BBF onset was (58±9) years old, including 6 males. Among the 6 patients who used bronchial silicone plug as plugging material in the first SBO treatment, 1 case was successfully plugged, 2 cases did not achieve symptoms relief after plugging, 2 cases coughed up the plugging device immediately after surgery, and 1 case developed a new fistula. Autologous blood and thrombin were used as sealing materials in 2 patients, and both failed. Among the 7 patients who received subsequent closure treatment, bronchial silicone plug+bullet-covered stent (1 case) and bronchial silicone plug+bronchial unidirectional valve (1 case) were successful. After 2-6 times of bronchial silicone plug (5 cases), fistula were successfully blocked in 3 cases, and the frequency and volume of bile-like sputum decreased by 50% or more in 2 cases. The main postoperative complications were fever and cough (expectoration) in 7 and 6 cases, respectively. During the follow-up period, 2 patients were lost to follow-up, and the remaining 6 patients were followed up for 2-31 months. During the follow-up period, the effect of closure treatment was basically stable, and there was no death case. Conclusion: SBO therapy provides a safe and feasible palliative treatment for BBF.

Comparison of the cardiometabolic profiles of adolescents conceived through ART with those of a non-ART cohort

STUDY QUESTION

Is the cardiometabolic health of adolescents conceived through ART worse than that of their counterparts conceived without ART?

SUMMARY ANSWER

The majority of cardiometabolic and vascular health parameters of adolescents conceived through ART are similar or more favourable, than those of their counterparts of similar age and conceived without ART.

WHAT IS KNOWN ALREADY

It has been proposed that the cardiometabolic health of offspring conceived with ART may be unfavourable compared to that of their counterparts conceived without ART. The literature pertaining to cardiometabolic health of offspring conceived after ART is contradictory, but generally suggests unfavourable cardiometabolic health parameters, such as an increase in blood pressure (BP), vascular dysfunction and adiposity, as well as unfavourable glucose and lipid profiles. With over 8 million children and adults born through ART worldwide, it is important to investigate whether these early signs of adverse cardiometabolic differences persist into adolescence and beyond.

STUDY DESIGN, SIZE, DURATION

The Growing Up Healthy Study (GUHS) is a prospective cohort study that recruited 303 adolescents and young adults conceived after ART (aged 13-21 years) and born between 1991 and 2001 in Western Australia. Their health parameters, including cardiometabolic factors, were assessed and compared with counterparts from the Raine Study Generation 2 (Gen2). The 2868 Gen2 participants were born 1989-1992 and are representative of the Western Australian adolescent population. At ∼17 years of age (2013-2017), 163 GUHS participants replicated assessments previously completed by Gen2 at a similar age.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Cardiometabolic parameters were compared between a total of 163 GUHS and 1457 Gen2 adolescents. Separate male (GUHS n = 81, Gen2 n = 735) and female (GUHS n = 82, Gen2 n = 722) analyses were conducted. Assessments consisted of a detailed questionnaire including health, lifestyle and demographic parameters, anthropometric assessments (height, weight, BMI, waist circumference and skinfold thickness), fasting serum biochemistry, arterial stiffness and BP (assessed using applanation tonometry). Abdominal ultrasonography was used to assess the presence and severity of hepatic steatosis, and thickness of abdominal fat compartments. Non-alcoholic fatty liver disease (NAFLD) was diagnosed if there was sonographic fatty liver in the absence of significant alcohol consumption. Chi2, Fisher's exact and Mann-Whitney U tests, performed in SPSS V25, examined cohort differences and generalized estimating equations adjusted for the following covariates: singleton vs non-singleton pregnancy, birthweight (z-score), gestational age, BMI, smoking, alcohol consumption in the past 6 months and parent cardiovascular status. Arterial stiffness measures and waist circumference were additionally adjusted for height, and female analyses were additionally adjusted for use of oral contraceptives in the preceding 6 months.

MAIN RESULTS AND THE ROLE OF CHANCE

In adjusted analyses, GUHS females had a lower BMI (22.1 vs 23.3 kg/m2, P = 0.014), and thinner skinfolds (triceps, subscapular, mid-abdominal; 16.9 vs 18.7 mm, P = 0.021, 13.4 vs 15.0 mm, P = 0.027, 19.7 vs 23.2 mm, P < 0.001, respectively), whereas males were not significantly different. Waist circumference was lower in GUHS adolescents (males: 78.1 vs 81.3 cm, P = 0.008, females: 76.7 vs 83.3 cm, P = 0.007). There were no significant differences between the two groups in glucose, insulin, homeostatic model assessment for insulin resistance, low-density lipoprotein cholesterol, non-high-density lipoprotein cholesterol (non-HDL-C), total cholesterol (TC), alanine aminotransferase and high-sensitivity C-reactive protein in both sexes. In females, serum triglycerides were lower in GUHS adolescents (1.0 vs 1.2 mmol/l, P = 0.029). GUHS males had higher serum HDL-C (1.1 vs 1.0 mmol/l, P = 0.004) and a lower TC/HDL-C ratio (3.2 vs 3.6, P = 0.036). There were no significant differences in the prevalence of NAFLD or steatosis severity scores between the cohorts in males and females. GUHS females had less subcutaneous adipose tissue (9.4 vs 17.9 mm, P < 0.001), whereas GUHS males had greater visceral adipose thickness (44.7 vs 36.3 mm, P < 0.001). There was no significant difference in pre-peritoneal adipose thickness. Pulse wave velocity was lower in GUHS males (5.8 vs 6.3 m/s, P < 0.001) and heart rate corrected augmentation index was lower in GUHS females (-8.4 vs -2.7%, P = 0.048). There were no significant differences in BP or heart rate in males or females between the two groups.

LIMITATIONS, REASONS FOR CAUTION

Despite the substantial study size and the unique study design of the ART cohort, we were unable to differentiate between different types of ART, due to the low number of ICSI cycles (e.g. IVF vs ICSI), draw definite conclusions, or relate the outcomes to the cause of infertility. Considering the differences in time points when both cohorts were studied, external factors could have changed, which could not be accounted for. Given the observational nature of this study, causation cannot be proven.

WIDER IMPLICATIONS OF THE FINDINGS

Contrary to our hypothesis and previous findings focussing mainly on childhood, this study reports mostly similar or favourable cardiometabolic markers in adolescents conceived with ART compared to those conceived without ART. The greater visceral adipose thickness, particularly present in males, requires further investigation. While these findings are generally reassuring, future well-designed and appropriately powered studies are required to definitively address the issue of cardiometabolic health in ART adults.

STUDY FUNDING/COMPETING INTEREST(S)

This project was supported by NHMRC project grant number 1042269 and R.J.H. received education grant funding support from Ferring Pharmaceuticals. R.J.H. is the Medical Director of Fertility Specialists of Western Australia and a shareholder in Western IVF. He has received educational sponsorship from MSD, Merck-Serono and Ferring Pharmaceuticals. P.B. is the Scientific Director of Concept Fertility Centre, Subiaco, Western Australia. J.L.Y. is the Medical Director of PIVET Medical Centre, Perth, Western Australia.

TRIAL REGISTRATION NUMBER

N/A.

O-072 Markers of cardiometabolic health of adolescents conceived through assisted reproductive technologies (ART) appear reassuring

Study question

Is the cardiometabolic health of adolescents conceived through ART worse than that of their spontaneously-conceived counterparts?

Summary answer

The majority of cardiometabolic and vascular health parameters of ART-conceived adolescents are more favourable than those of their spontaneously-conceived counterparts of similar age.

What is known already

It has been proposed that ART induces epigenetic alterations during embryonic development which could lead to cardiometabolic disease later in life. However, individuals requiring ART may themselves be metabolically less healthy than the general population, which could lead to a genetically increased risk of cardiometabolic disorders in the offspring, rather than the ART procedure. The literature pertaining to cardiometabolic health of ART-conceived offspring is contradictory, but generally suggests unfavourable cardiometabolic health parameters. With over 8 million children and adults born through ART worldwide, it is imperative to investigate whether early signs of adverse cardiometabolic differences persist into adolescence and beyond.

Study design, size, duration

The Growing Up Healthy Study (GUHS) is a prospective study that recruited 303 ART-conceived adolescents, born 1991-2001 in Western Australia. Their health parameters, including cardiometabolic factors, were assessed and compared with spontaneously conceived counterparts of similar socioeconomic background and age from the Raine Study Generation 2 (Gen2). The 2868 Gen2 participants were born 1989-1992 and are representative of the Western Australian adolescent population. At age 16-17 (2013-2017), GUHS participants replicated assessments previously completed by Gen2.

Participants/materials, setting, methods

Cardiometabolic parameters were compared between 165 GUHS (male = 50.9%) and 1690 Gen2 (male = 49.8%) adolescents. Assessments consisted of a detailed questionnaire; health and demographic parameters, anthropometric assessments; height, weight, body-mass index (BMI), waist circumference and skinfold thickness, fasting serum biochemistry, arterial stiffness and blood pressure assessment using applanation tonometry, assessment of non-alcoholic fatty liver (NAFLD) and thickness of abdominal fat compartments using ultrasonography. Chi2, Fisher’s Exact and Mann-Whitney U tests, performed in SPSS V25, examined cohort differences.

Main results and the role of chance

GUHS adolescents appeared to be healthier from a cardiometabolic perspective than their Gen2 counterparts. They were leaner, with lower BMI (median: 21.23 vs. 22.06, P = 0.004), lower waist circumference (median: 74.10 vs. 76.75 cm, P = 0.031), and thinner skinfolds (triceps median: 12.1 vs. 14.0 mm, P = 0.019, subscapular median: 10.6 vs. 11.9 mm, P &lt; .001, mid-abdominal median: 16.0 vs. 19.9 mm, P &lt; 0.001, supraspinal median: 10.7 vs. 13.5 mm, P &lt; 0.001). No significant differences were detected in the following serum fasting parameters: glucose, insulin, HOMA-IR, LDL cholesterol, total cholesterol, cholesterol/HDL-ratio, triglycerides, CRP and ALT. HDL cholesterol levels were more favourable in GUHS (P &lt; 0.001). NAFLD was present in 10.9% of GUHS vs. 15.2% of Gen2 adolescents (P = 0.174), with no difference in steatosis severity score (P = 0.309). ART offspring had less subcutaneous adipose tissue (median: 8.0 vs. 14.0 mm, P &lt; .001), more visceral adipose tissue (median: 40.0 vs. 32.0 mm, P &lt; 0.001), with no difference in pre-peritoneal adipose tissue (P = 0.087). Measures of arterial stiffness were lower in GUHS. Pulse wave velocity: median 6.1 vs. 6.4 m/s, P &lt; 0.001 and heart rate corrected augmentation index: median -10.25 vs. -8.00, P = 0.006. No significant differences in blood pressure or heart rate were detected. Stratification by sex did not greatly alter the results.

Limitations, reasons for caution

Despite the substantial study size and the unique study design, we were unable to differentiate between different types of ART (e.g. IVF vs. ICSI), draw definite conclusions or relate outcomes to cause of infertility. Given the observational character of this study, causation cannot be proven.

Wider implications of the findings

In this study we did not detect any adverse effect of ART on cardiometabolic health at adolescence, in contrast to some studies. Given the lack of consensus, future well-designed and appropriately-powered studies are necessary to investigate cardiometabolic health in ART adults.

Trial registration number

not applicable

Retrieval Analysis of Polyethylene Components in Rotating Hinge Knee Arthroplasty Implants

BACKGROUND

This study examined a cohort of retrieved rotating hinge (RH) total knee arthroplasty implants of four different designs with emphasis on the surface damage observed on the polyethylene components. Our purpose was to determine if differences in polyethylene damage existed among the designs, and if those differences could be explained by differences in design characteristics.

MATERIALS AND METHODS

Seventy-two RH implants from four manufacturers (DePuy LPS/SROM, Zimmer NexGen, Stryker Howmedica MRH, and Biomet Finn-OSS) removed at the time of revision performed between 2002 and 2017 were identified in our institutional retrieval registry. Damage to the surfaces of the polyethylene was assessed using a subjective grading system and evaluated in multiple zones. Design characteristics that were evaluated included the following: location of the dwell point on the polyethylene component, posterior position of the axle, and amount of hyperextension and rotation allowed by the implant.

RESULTS

There were no differences in total damage scores between the four implant groups (P = .45). The Stryker Howmedica MRH group showed the least backside wear of all implants but significantly more articular-sided wear compared with two of the other three groups. All implants except NexGen showed increased total damage scores in implants revised for mechanical (vs nonmechanical) reasons and in implants with a longer duration of implantation.

CONCLUSION

No single implant design emerged as superior in terms of minimizing polyethylene wear damage. Polyethylene damage existed in various locations but was not different in severity across designs, suggesting that there is no clear superior RH design that minimizes overall articular surface wear compared with other designs.

DNA methylation patterns within whole blood of adolescents born from assisted reproductive technology are not different from adolescents born from natural conception

STUDY QUESTION

Do the epigenome-wide DNA methylation profiles of adolescents born from ART differ from the epigenome of naturally conceived counterparts?

SUMMARY ANSWER

No significant differences in the DNA methylation profiles of adolescents born from ART [IVF or ICSI] were observed when compared to their naturally conceived, similar aged counterparts.

WHAT IS KNOWN ALREADY

Short-term and longer-term studies have investigated the general health outcomes of children born from IVF treatment, albeit without common agreement as to the cause and underlying mechanisms of these adverse health findings. Growing evidence suggests that the reported adverse health outcomes in IVF-born offspring might have underlying epigenetic mechanisms.

STUDY DESIGN, SIZE, DURATION

The Growing Up Healthy Study (GUHS) is a prospective study that recruited 303 adolescents and young adults, conceived through ART, to compare various long-term health outcomes and DNA methylation profiles with similar aged counterparts from Generation 2 from the Raine Study. GUHS assessments were conducted between 2013 and 2017. The effect of ART on DNA methylation levels of 231 adolescents mean age 15.96 ± 1.59 years (52.8% male) was compared to 1188 naturally conceived counterparts, 17.25 ± 0.58 years (50.9% male) from the Raine Study.

PARTICIPANTS/MATERIALS, SETTING, METHODS

DNA methylation profiles from a subset of 231 adolescents (13-19.9 years) from the GUHS, generated using the Infinium Methylation Epic Bead Chip (EPIC) array were compared to 1188 profiles from the Raine Study previously measured using the Illumina 450K array. We conducted epigenome-wide association approach (EWAS) and tested for an association between the cohorts applying Firth's bias reduced logistic regression against the outcome of ART versus naturally conceived offspring. Additionally, within the GUHS cohort, we investigated differences in methylation status in fresh versus frozen embryo transfers, cause of infertility as well as IVF versus ICSI conceived offspring. Following the EWAS analysis we investigated nominally significant probes using Gene Set Enrichment Analysis (GSEA) to identify enriched biological pathways. Finally, within GUHS we compared four estimates (Horvath, Hanuum, PhenoAge [Levine], and skin Horvath) of epigenetic age and their correlation with chronological age.

MAIN RESULTS AND THE ROLE OF CHANCE

Between the two cohorts, we did not identify any DNA methylation probes that reached a Bonferroni corrected P-value < 1.24E-0.7. When comparing IVF versus ICSI conceived adolescents within the GUHS cohort, after adjustment for participant age, sex, maternal smoking, multiple births, and batch effect, three methylation probes (cg15016734, cg26744878 and cg20233073) reached a Bonferroni correction of 6.31E-08. After correcting for cell count heterogeneity, two of the aforementioned probes remained significant and an additional two probes (cg 0331628 and cg 20235051) were identified. A general trend towards hypomethylation in the ICSI offspring was observed. All four measures of epigenetic age were highly correlated with chronological age and showed no evidence of accelerated epigenetic aging within their whole blood.

LIMITATIONS, REASONS FOR CAUTION

The small sample size coupled with the use of whole blood, where epigenetic differences may occur in other tissue. This was corrected by the utilized statistical method that accounts for imbalanced sample size between groups and adjusting for cell count heterogeneity. Only a small portion of the methylome was analysed and rare individual differences may be missed.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings provide further reassurance that the effects of the ART manipulations occurring during early embryogenesis, existing in the neonatal period are indeed of a transient nature and do not persist into adolescence. However, we have not excluded that alternative epigenetic mechanisms may be at play.

STUDY FUNDING/COMPETING INTEREST(S)

This project was supported by NHMRC project Grant no. 1042269 and R.J.H. received funding support from Ferring Pharmaceuticals Pty Ltd. R.J.H. is the Medical Director of Fertility Specialists of Western Australia and a shareholder in Western IVF. He has received educational sponsorship from Merck Sharp & Dohme Corp.- Australia, Merck-Serono Australia Pty Ltd and Ferring Pharmaceuticals Pty Ltd. P.B. is the Scientific Director of Concept Fertility Centre, Subiaco, Western Australia. J.L.Y. is the Medical Director of PIVET Medical Centre, Perth, Western Australia. The remaining authors have no conflicts of interest.

Five-Year Follow-Up of Clinical Outcomes with an Anatomic Dual-Mobility Acetabular System: A Multicenter Study

Background

The dual-mobility implant system has been shown to increase impingement-free range of motion and decrease dislocation risk by increasing the effective head size. In addition, the anatomic dual-mobility (ADM) cup offers relief between the acetabular shell rim and the iliopsoas tendon. This study was designed to review a series of hips implanted with the ADM acetabular cup to examine clinical outcomes after 5 years of implantation at multiple orthopaedic centers.

Methods

We retrospectively queried our prospectively collected total joint arthroplasty registry for patients who underwent total hip arthroplasty with an ADM cup from January 2008 to December 2012 at 4 different orthopaedic institutions and who had minimum 5-year follow-up. Harris Hip Scores and visual analog scale scores were evaluated. Postoperative complications, dislocations, and revisions for any reason were recorded.

Results

A total of 142 patients had a mean follow-up of 5.7 years (range: 5.0 to 8.0 years). Radiographic analysis showed no radiolucent lines, osteolysis, or acetabular loosening. There were no dislocations in this patient series. Two (1.2%) hips required a revision because of adverse local tissue reactions related to corrosion from a recalled modular neck stem, but this was unrelated to the ADM cup. The mean Harris Hip pain scores increased from 17 points preoperatively to 39 points at the most recent follow-up (P < .001). The mean Harris Hip function score increased from an average of 29 points preoperatively to 38 points at the most recent follow-up (P < .001). The mean visual analog scale score showed patient improvement from 6.5 preoperatively to 1.2 postoperatively (P < .001).

Conclusions

ADM prostheses were designed to reduce the risk of dislocation by increasing the size of the effective femoral head. In this multicenter study of ADM cups used in primary total hip arthroplasty, we demonstrated good clinical and radiographic outcomes, no dislocations, and no revisions at midterm 5-year minimum follow-up. Patient-reported outcome measures were also improved, supporting the use of this implant.

Machine learning and clinical epigenetics: a review of challenges for diagnosis and classification

BACKGROUND

Machine learning is a sub-field of artificial intelligence, which utilises large data sets to make predictions for future events. Although most algorithms used in machine learning were developed as far back as the 1950s, the advent of big data in combination with dramatically increased computing power has spurred renewed interest in this technology over the last two decades.

MAIN BODY

Within the medical field, machine learning is promising in the development of assistive clinical tools for detection of e.g. cancers and prediction of disease. Recent advances in deep learning technologies, a sub-discipline of machine learning that requires less user input but more data and processing power, has provided even greater promise in assisting physicians to achieve accurate diagnoses. Within the fields of genetics and its sub-field epigenetics, both prime examples of complex data, machine learning methods are on the rise, as the field of personalised medicine is aiming for treatment of the individual based on their genetic and epigenetic profiles.

CONCLUSION

We now have an ever-growing number of reported epigenetic alterations in disease, and this offers a chance to increase sensitivity and specificity of future diagnostics and therapies. Currently, there are limited studies using machine learning applied to epigenetics. They pertain to a wide variety of disease states and have used mostly supervised machine learning methods.

[Application of meticulous anatomy skills with straight bipolar electric coagulation forceps in thyroid surgery]

Objective: To compare the efficacies of the two techniques of "micro-hemostasis and micro-cutting" with straight bipolar electrocoagulation forceps and traditional clamp-ligation for hemostasia in thyroid surgery. Methods: A total of 228 patients who underwent surgical treatment for thyroid neoplasms in our hospital between January 2015 and December 2018 were retrospectively analyzed, including 50 males and 178 females, aged 23-68 years old. Of those, 150 cases as electric knife group received traditional thyroid surgery between January 2015 and December 2018 and 78 cases as bipolar electrocoagulation group received thyroid surgery by using the technique of bipolar electrocoagulation with meticulous anatomy between January 2018 and December 2018. The total operation time, single operation time, intraoperative hemorrhage, postoperative drainage volume on the first day, postoperative hoarseness and hypocalcemia were compared between the two groups. SPSS 16.0 was used to analyze the data. Results: The total operation time and intraoperative hemorrhage in the bipolar electrocoagulation group were significantly lower than those in the electric knife group ((59.33±18.29)min vs (77.21±25.39)min, (14.83±9.22)ml vs (36.86±11.80)ml, all P<0.01). The single operation time of the bipolar electrocoagulation group was shorter than that of the electric knife group((10.25±6.16) min vs (20.34±7.24)min, (16.25±7.15)min vs (35.68±8.25)min, (12.12±5.25)min vs (20.68±7.26)min, t value was 3.948,16.262,8.238, all P<0.01).There was no significant difference between the two groups in postoperative drainage volume on the first day (P>0.05) and the incidence of postoperative hoarseness (P>0.05), while the incidence of hypocalcemia in the bipolar electrocoagulation group(10.26%) was lower than that in the electric knife group(21.33%,χ(2)=4.353, P<0.05). Conclusions: The fine dissection for thyroid operation can be achieved by using straight bipolar electrocoagulation tweezers. The use of "micro-hemostasis" and "micro-cutting" technique with bipolar electrocoagulation tweezers can greatly reduce intraoperative bleeding, operation time and postoperative complication.

Multicenter Evaluation of a Modular Dual Mobility Construct for Revision Total Hip Arthroplasty

INTRODUCTION

Modular Dual Mobility (MDM) constructs in total hip arthroplasty (THA) offer increased hip stability compared with constrained liners, without compromising hip range of motion. The purpose of this study was to evaluate outcomes of revision THA using MDM.

METHODS

The study was a multiinstitutional retrospective cohort study of 315 hips that underwent revision THA using MDM between 2011 and 2017. Clinical outcomes and reasons for failure were collected.

RESULTS

Three hundred fifteen patients met 1-year minimum follow-up (mean 3.3 years). Nine hips had instability postoperatively (2.9%), and 30 hips required reoperation (9.5%). Seven had recurrent instability (6.5%) which was associated with liner-only exchange (P = .021) and liner outer diameter of ≤ 38 mm (P = .016).

CONCLUSION

Revision THA with MDM provided a low rate of instability and reoperation in a revision cohort. Recurrent instability following use of MDM in revision THA was associated with retention of the acetabular component and polyethylene outer diameter ≤ 38 mm.

LEVEL OF EVIDENCE

Therapeutic Level III.

The Use of Aspirin for Prophylaxis Against Venous Thromboembolism Decreases Mortality Following Primary Total Joint Arthroplasty

BACKGROUND

The use of aspirin as prophylaxis against venous thromboembolism (VTE) following total joint arthroplasty (TJA) has increased in popularity; however, the potential cardioprotective effects of aspirin when administered as VTE prophylaxis remain unknown. The present study investigated the influence of VTE prophylaxis, including aspirin, on mortality following TJA.

METHODS

We retrospectively reviewed 31,133 patients who underwent primary TJA from 2000 to 2017. Patient demographics, body mass index, and comorbidities were obtained from an electronic chart query. Patients were allocated into 2 cohorts on the basis of the VTE prophylaxis administered: aspirin (25.9%, 8,061 patients) and non-aspirin (74.1%, 23,072 patients). Mortality was assessed with use of an institutional mortality database that is updated biannually. Univariate and multivariate regression analyses were performed.

RESULTS

The overall mortality rate was 0.2% and 0.6% at 30 days and 1 year after TJA, respectively. The use of aspirin was independently associated with lower risk of death at both 30 days (odds ratio [OR], 0.39; p = 0.020) and 1 year (OR, 0.51; p = 0.004). Patients in the non-aspirin cohort showed 3 times the risk of death at 30 days compared with the aspirin cohort (0.3% compared with 0.1%; p = 0.004), and twice the risk of death at 1 year (0.7% compared with 0.3%; p < 0.001). At 1 year, the primary cause of death in the non-aspirin group was cardiac-related (46 of 23,072, 0.20%). In the aspirin group, the rate of cardiac-related death was almost 5 times lower (3 of 8,061, 0.04%; p = 0.005). Risk factors for mortality at 1 year included higher age (p < 0.001), male sex (p = 0.020), history of congestive heart failure (p = 0.003), cerebrovascular disease (p < 0.001), malignancy (p < 0.001), and history of prior myocardial infarction (p < 0.001).

CONCLUSIONS

The present study demonstrates that the use of aspirin as prophylaxis against VTE following TJA may reduce the risk of mortality. Given the numerous options available and permitted by the current guidelines, orthopaedic surgeons should be aware of the potential added benefits of aspirin when selecting a VTE-prophylactic agent.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Effects of postnatal omega-3 fatty acid supplementation on offspring pro-resolving mediators of inflammation at 6 months and 5 years of age: A double blind, randomized controlled clinical trial

BACKGROUND

Resolution of inflammation is an active process involving specialised pro-resolving mediators (SPMs) generated from the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Omega-3 fatty acid supplementation during infancy may provide an intervention strategy to modify SPMs and reduce oxidative stress. This study evaluates the effect of omega-3 fatty acid supplementation in infancy on SPMs and F₂-isoprostanes from 6 months to 5 years of age.

METHODS

In a double-blind, placebo-controlled, parallel-group study design, 420 infants were randomized to a daily supplement of omega-3 fatty acids (280mg DHA and 110mg EPA) or olive oil (control), from birth to age 6 months. Blood was collected at birth (cord blood), 6 months, 12 months and 5 years. Plasma SPMs included 18-HEPE, E-series resolvins, 17-HDHA, D-series resolvins, 14-HDHA, 10S,17S-DiHDoHE, MaR1 and PD1. F₂-isoprostanes were measured in plasma and urine, as markers of oxidative stress in vivo.

RESULTS

The change in the concentration of 18-HEPE from birth to 6 months was greater in the omega-3 fatty acid group (P_{timepoint*group}=0.04) with levels at 6 months significantly higher than controls (P=0.02). Other SPMs were not different between the groups at any time point. Plasma 18-HEPE concentration were associated with erythrocyte EPA concentrations after age and group adjustments (P<0.001), but not with allergic outcomes at 12 months. There were no between-group differences in plasma and urinary F₂-isoprostanes at any time point.

CONCLUSION

Omega-3 fatty acid supplementation from birth to 6 months of age increased SPM at 6 months but the effects were not sustained after supplementation ceased. Given that 18-HEPE is a biologically active metabolite, future studies should examine how the increase in 18-HEPE relates to potential health benefits of omega-3 fatty acid supplementation in infancy.

[Value of evaluating the coronary collateral circulation by transluminal attenuation gradient in patients with chronic total occlusion and related influencing factors]

Objective: To observe the value of evaluating the coronary collateral circulation of chronic total occlusion (CTO) by transluminal attenuation gradient (TAG) and Rentrop grading, and analyze the influencing factors for coronary collateral circulation. Methods: A total of 179 CTO patients admitted to Beijing Anzhen hospital during June 2013 to August 2016 were included in this study.All patients received coronary computed tomographic angiography (CCTA) examination before coronary angiography.Finally, 75 patients (79 vessels) were enrolled.Patients were divided into two groups on the basis of Rentrop classification.The Rentrop 3 was defined as a well-developed coronary collateral circulation group, including 50 CTO vessels, Rentrop 2 or below was defined as poorly-developed collateral circulation group, including 29 vessels.TAG values in patients with various Rentrop grades were analyzed.Univariate and multivariate analysis were used to determine the predictors of collateral circulation. Results: TAG increased consistently in proportion to the angiographic extent of collateral flow (TAG was (-33.6±24.4), (-16.5±15.7) and (-12.8±15.8) HU/10 mm in patients with Rentrop grade 0 or 1, 2 and 3, respectively, P=0.007). Number of good collateral circulation vessels predicted by TAG≥15.6 HU/10 mm was 45(57.0%, 45/79), and 50 (63.3%, 50/79) by Rentrop grade (P=0.383). Prevalence of diabetes was significantly lower (20.8%(10/48) vs. 48.1%(13/27), P=0.01), while history of previous myocardial infarction (MI) was significantly higher (35.4%(17/48) vs. 11.1%(3/27), P=0.02) in patients with good collateral circulation than in patients with poor collateral circulation.The TAG of the good collateral circulation group was significantly higher than in poorly collateral circulation group ((-12.8±15.8) HU/10 mm vs. (-21.2±19.6) HU/10mm, P=0.041). Multiple logistic regression analysis revealed that history of MI (OR=0.196, 95%CI 0.041-0.936, P=0.041) and diabetes(OR=6.604, 95%CI 1.726-25.274, P=0.006) were independent predictors of coronary collateral circulation. Conclusions: TAG could be used to evaluate status of coronary collateral circulation.Presence of MI history and absence of diabetes history are the two independent predictors of well-developed coronary collateral circulation in CTO patients.

[The relationship between myocardial bridge in mural coronary artery segment and coronary atherosclerosis]

Objective: The myocardial bridging (MB) prevalence, anatomic characteristics of MB, and the relationship between characteristics of MB in mural coronary artery segment and coronary atherosclerosis were analyzed. Methods: In this perspective nonrandomized controlled study, a total of 1 132 patients who admitted to our hospital for suspected or known coronary artery disease from January 2012 to June 2013 were enrolled. All patients underwent dual-source 64-slice spiral CT coronary angiography. The general patient characteristics including gender, age, history of hypertension, diabetes, hyperlipidemia and smoking, serum level of total cholesterol (TC) and LDL-C were recorded. The length, depth and the degree of compression of myocardial bridge in systolic or diastolic phase were also analyzed in patients with MB. The relationship between MB and coronary atherosclerosis, the characteristics of MB and coronary atherosclerosis were analyzed by Spearman correlation analysis, univariate logistic regression analysis, variate logistic regression analysis and linear regression analysis. Results: Myocardial bridging was detected in 330 out of 1 132 patients, and MB was mostly located in the mural coronary artery (329/330) and at the mid-distal segment of the left anterior descending artery (LAD). Average MB length was 20.1 mm (3.3-95.5 mm) and the average depth was 2.13 mm (0.24-12.40 mm). There were 140 patients with intramyocardial MB (42.6%) and 189 patients with superficial MB (57.4%). Myocardial bridging was an independent protective factor of coronary atherosclerosis (OR=0.361, P=0.000) and the proximal segment of MB was more susceptible to atherosclerosis compared to the distal segment of MB (P=0.000). Multivariate analysis revealed that age, hypertension and the degree of compression of myocardial bridge in diastolic phase were independent factors related to the atherosclerosis (odds ratio: 1.064, 2.186 and 1.049 respectively, P value: 0.000, 0.002 and 0.000). The depth of MB was significantly correlated with systolic or diastolic narrowing(OR: 4.227, 3.398 and P value: 0.000, 0.001). Conclusions: The prevalence of myocardial bridging is 29% in this patient cohort. The proximal segment of myocardial bridging in mural coronary artery is more susceptible to atherosclerosis. In addition, the depth of myocardial bridging and the degree of compression of myocardial bridge in diastolic phase are the independent factors related to atherosclerosis.

[Impact of different antithrombotic therapy strategy on prognosis in coronary heart disease patients combining with atrial fibrillation: a meta analysis]

Objective: To evaluate the impact of various anticoagulation antiplatelet therapy strategies on the prognosis of patients with coronary heart disease combining with atrial fibrillation. Methods: Present meta analysis was performed according to search results on English EMBASE database by computer retrieval, Pubmed, the Cochrane Central Register of Controlled Trials, Medline, Chinese CBM database, CNKI database, Wan Fang database, China science and technology papers online electronic databases, manual retrieval for important international conference proceedings up to April 30 2016. Trials published in English and Chinese language, which met the Cochrane system evaluation requirements were included and the inclusion and exclusion criteria were made based on Cochrane system evaluation requirements. The end point is the incident of major adverse cardiac events (MACE), ischemic stroke and major bleeding events. The patients were randomly assigned into triple antithrombotic therapy (aspirin+ clopidogrel+ warfarin) group and dual antiplatelet therapy (aspirin+ clopidogrel) group.The collected full-text literatures underwent further quality assessment of the risks of bias using RevMan 5.3 software. Impact of various antithrombotic therapeutic strategies on the outcome of coronary heart disease patients combining with atrial fibrillation were evaluated. Results: In this meta analysis, 12 randomized controlled trials with 11 353 patients were included. Among these patients, 3 486 patients received triple antithrombotic therapy and 7 867 patients received dual anti-platelet therapy. There was no significant difference in incidence rate of MACE (OR=0.93, 95%CI 0.74-1.18, P>0.05) and the incidence rate of ischemic stroke (OR=0.88, 95%CI 0.70-1.10, P=0.27) between the two patients groups. However, the incidence rate of major bleeding events in triple antithrombotic therapy group was twice higher than that in dual anti-platelet therapy (OR=1.94, 95%CI 1.33-2.82, P=0.000 6). Conclusion: Compared with dual anti-platelet therapy strategy, coronary heart disease patients combining with atrial fibrillation who were treated by triple antithrombotic therapy strategy have the similar outcome on risk of ischemic stroke, but higher risk of major bleeding events.

[The clinical efficacy analysis of the surgery of the posterior approach parotid gland region resection preserving retinal ganglion and parotid fascia]

Objective:To explore the clinical efficacy analysis the surgery of the posterior approach parotid gland resection preserving retinal ganglion and parotid fascia for the treatment of benign parotid tumour.Method:One hundred and twelve cases were randomly divided into control group and treatment group. The control group was treated by anterior approach parotid gland region resection preserving retinal ganglion and parotid fascia. The treatment group was treated by posterior approach parotid gland region resection preserving retinal ganglion and parotid fascia. The data of operation time, postoperative local numbness, Frey syndrome, facial paralysis and postoperative recurrence case were analyzed. Result:There was no postoperative recurrence case in both two groups, and there was no significant difference between two the groups in operation time and the percent of facial paralysis（all P>0.05）.However, the percent of postoperative local numbness and Frey syndrome in control group were significantly higher than those in treatment group（all P<0.05）. Conclusion:The treatment group had similar clinical efficacy with the traditional surgical operation. In addition, the operation of treatment group contributed to decreased postoperative complications.

Genome-wide methylation analysis identifies differentially methylated CpG loci associated with severe obesity in childhood

Childhood obesity is a major public health issue. Here we investigated whether differential DNA methylation was associated with childhood obesity. We studied DNA methylation profiles in whole blood from 78 obese children (mean BMI Z-score: 2.6) and 71 age- and sex-matched controls (mean BMI Z-score: 0.1). DNA samples from obese and control groups were pooled and analyzed using the Infinium HumanMethylation450 BeadChip array. Comparison of the methylation profiles between obese and control subjects revealed 129 differentially methylated CpG (DMCpG) loci associated with 80 unique genes that had a greater than 10% difference in methylation (P-value < 0.05). The top pathways enriched among the DMCpGs included developmental processes, immune system regulation, regulation of cell signaling, and small GTPase-mediated signal transduction. The associations between the methylation of selected DMCpGs with childhood obesity were validated using sodium bisulfite pyrosequencing across loci within the FYN, PIWIL4, and TAOK3 genes in individual subjects. Three CpG loci within FYN were hypermethylated in obese individuals (all P < 0.01), while obesity was associated with lower methylation of CpG loci within PIWIL4 (P = 0.003) and TAOK3 (P = 0.001). After building logistic regression models, we determined that a 1% increase in methylation in TAOK3, multiplicatively decreased the odds of being obese by 0.91 (95% CI: 0.86 – 0.97), and an increase of 1% methylation in FYN CpG3, multiplicatively increased the odds of being obese by 1.03 (95% CI: 0.99 – 1.07). In conclusion, these findings provide evidence that childhood obesity is associated with specific DNA methylation changes in whole blood, which may have utility as biomarkers of obesity risk.

Prenatal omega-3 fatty acid supplementation does not affect offspring telomere length and F2-isoprostanes at 12 years: A double blind, randomized controlled trial

BACKGROUND

Oxidative stress and nutritional deficiency may influence the excessive shortening of the telomeric ends of chromosomes. It is known that stress exposure in intrauterine life can produce variations in telomere length (TL), thereby potentially setting up a long-term trajectory for disease susceptibility.

OBJECTIVE

To assess the effect of omega-3 long chain polyunsaturated fatty acid (n-3 LCPUFA) supplementation during pregnancy on telomere length and oxidative stress in offspring at birth and 12 years of age (12y).

DESIGN

In a double-blind, placebo-controlled, parallel-group study, 98 pregnant atopic women were randomised to 4g/day of n-3 LCPUFA or control (olive oil [OO]), from 20 weeks gestation until delivery. Telomere length as a marker of cell senescence and plasma and urinary F2-isoprostanes as a marker of oxidative stress were measured in the offspring at birth and 12y.

RESULTS

Maternal n-3 LCPUFA supplementation did not influence offspring telomere length at birth or at 12y with no changes over time. Telomere length was not associated with F2-isoprostanes or erythrocyte total n-3 fatty acids. Supplementation significantly reduced cord plasma F2-isoprostanes (P<0.001), with a difference in the change over time between groups (P=0.05). However, the differences were no longer apparent at 12y. Between-group differences for urinary F2-isoprostanes at birth and at 12y were non-significant with no changes over time.

CONCLUSIONS

This study does not support the hypothesis that n-3 LCPUFA during pregnancy provides sustained effects on postnatal oxidative stress and telomere length as observed in the offspring.

[Impact of adherence to statins on cardiovascular adverse events in patients with coronary artery disease: a meta-analysis]

OBJECTIVE

To evaluate the impact of different adherence mode to statins on cardiovascular adverse events in patients with coronary artery disease (CAD).

METHODS

Electronic searches, including PubMed, Scopus, Ovid MEDLINE, Ovid EMBASE, Ovid EBM Reviews CENTRAL, CINAHL, The Cochrane Library, Ovid PsycInfo, Wanfang data, CNKI and Science & Technology Magazine Online, were performed and all related literatures of all languages were retrieval till to March 1, 2015. The full text was obtained through manual retrieval, inter-library loan and document delivery service, or by contacting the author directly. According to inclusion and exclusion criteria, data was extracted dependently by two raters. The high adherence to statin was use defined by the ratio of statins cover time and the total time (proportion of days covered, PDC≥80%). Data were analyzed quantitatively using RevMan 5.1. Then implement subgroup analysis was made according to different statin adherence and classification of clinical outcomes. The impact of adherence to statin on cardiovascular events (all-cause mortality, non-fatal myocardial infarction, hospitalization due to unstable angina pectoris, heart insufficiency attack) in CAD patients was evaluated.

RESULTS

Present analysis enrolled eight relevant retrospective and observational studies. Because there were only few literatures describing the impact of statin adherence on clinical outcomes, we also included literatures with low adherence group (4 studies in PDC<80%, 2 studies in PDC<40% and 2 studies in PDC<20%). High adherence group includes 189 556 cases; low adherence group includes 11 384 cases. Compare with low adherence group, cardiovascular events rate reduced by 32% in high adherence group (OR=0.68, 95%CI 0.58-0.80, P<0.001). Subgroup analysis with 4 literatures with PDC≥80% or<80% showed that the cardiovascular events prominently decreased in high adherence group compared to low adherence group (OR=0.63, 95%CI 0.53-0.76, P<0.001). According to 5 literatures with all-cause mortality parameter, we also found a borderline decrease in all-cause mortality in high adherence group compared to low adherence group ( OR=0.67, 95%CI 0.44-1.02, P=0.06), while non-fatal cardiovascular events were significantly reduced by 18% in high adherence group (OR=0.82, 95%CI 0.77-0.87, P<0.001).

CONCLUSIONS

High adherence to statins is related to significantly lower cardiovascular events in CAD patients.

Staged Bilateral Total Knee Arthroplasty: Time of the Second Side

The purpose of this study was to determine if there was a safe time frame for performing the second total knee arthroplasty (TKA) in staged bilateral TKAs. Retrospectively, 589 TKAs were studied at a single institution from January 2000 to June 2012. Patients were excluded if they underwent simultaneous or staggered bilateral TKA during the same hospitalization. Patients were included if they underwent bilateral staged TKA during a different hospitalization within 21 to 90, 91 to 180, 181 to 270, and 271 to 360 days after the first TKA. In-hospital complications were determined using International Classification of Diseases, Ninth Revision codes for cardiac, pulmonary, urinary, deep vein thrombosis, wound complications, mechanical complications, and wound infections. Periprosthetic joint infection (PJI) was determined by hospital readmission records. There were 29 postoperative complication events (4.9%) and there was no difference between time groups and complications. The highest rates of PJI occurred when the second TKA was performed after 271 to 360 days (3.6%), followed by the early postoperative period after 21 to 90 days (2.7%). We could not identify a time frame for performing the second TKA in staged bilateral TKAs to reduce complications. A signal from the study suggests that complications, particularly PJI, may be lower if the second TKA is performed more than 90 days and less than 270 days after the first TKA, although this finding was not significant.

Identification of a dietary pattern associated with greater cardiometabolic risk in adolescence

BACKGROUND AND AIMS

Energy dense, high fat, low fibre diets may contribute to obesity in young people, however their relationships with other cardiometabolic risk factors are unclear. We examined associations between an 'energy-dense, high-fat and low-fibre' dietary pattern (DP) and cardiometabolic risk factors, and the tracking of this DP in adolescence.

METHODS AND RESULTS

Data was sourced from participants in the Western Australian Pregnancy (Raine) Cohort Study. At 14 and 17 y, dietary intake, anthropometric and biochemical data were measured and z-scores for an 'energy dense, high fat and low fibre' DP were estimated using reduced rank regression (RRR). Associations between DP z-scores and cardiometabolic risk factors were examined using regression models. Tracking of DP z-scores was assessed using Pearson's correlation coefficient. A 1 SD unit increase in DP z-score between 14 and 17 y was associated with a 20% greater odds of high metabolic risk (95% CI: 1.01, 1.41) and a 0.04 mmol/L higher fasting glucose in boys (95% CI: 0.01, 0.08); a 28% greater odds of a high-waist circumference (95% CI: 1.00, 1.63) in girls. An increase of 3% and 4% was observed for insulin and HOMA (95% CI: 1%, 7%), respectively, in boys and girls, for every 1 SD increase in DP z-score and independently of BMI. The DP showed moderate tracking between 14 and 17 y of age (r = 0.51 for boys, r = 0.45 for girls).

CONCLUSION

An 'energy dense, high fat, low fibre' DP is positively associated with cardiometabolic risk factors and tends to persist throughout adolescence.

Total joint arthroplasty in cancer patients

Increasing numbers of total joint arthroplasty (TJA) patients have a history, or an active diagnosis, of cancer. We aimed to evaluate the risk of early postoperative complications in these patients. In our series, a history of malignancy was associated with an elevated risk of ischemic cardiac events and postoperative deep vein thrombosis (DVT), while active malignancy was associated with increased respiratory and renal complications, hematoma/seroma formation and early postoperative mortality. Both groups presented increased rates of overall in-hospital complications. Patients with bone metastasis to the hip demonstrated increased DVT and 90-day mortality rates. Cancer patients have increased morbidity and mortality after TJA and should undergo comprehensive medical optimization and adapted thromboprophylaxis.

Total joint arthroplasty: should patients have preoperative dental clearance?

Obtaining dental clearance prior to elective total joint arthroplasty is a common practice; however, little published data exist to justify this requirement. Dental clearance data for 365 elective total knee and total hip arthroplasty patients were gathered prospectively. Of these patients, 358 (average age of 62.4 years; 157 men and 201 women; 152 primary total knee arthroplasties (TKAs), 16 revision TKA arthroplasties, one conversion TKA, 168 primary total hip (THAs) arthroplasties and 21 revision THA arthroplasties) proceeded to surgery and follow-up data were available for 355. A comparison group of 218 hip fracture patients (average age of 78.7 years; 52 men and 109 women; 137 THA and 81 hemiarthroplasties) with no preoperative dental clearance who were treated with hip arthroplasty was extracted retrospectively from an institutional database. Follow-up data were available for 161 of these patients. The incidence of dental pathology in the elective arthroplasty group was 8.8%. Early postoperative infection requiring surgical treatment occurred in six patients (1.7%) in the dental clearance elective arthroplasty group and in four patients (2.5%) in the hip fracture arthroplasty group. No statistical difference was found between the two groups. This suggests that the perceived need for routine preoperative dental screening for all hip and knee arthroplasty patients should be reassessed.

Polyunsaturated fatty acid intake and blood pressure in adolescents

Evidence that intake of polyunsaturated fatty acids (PUFAs) may modify blood pressure (BP) is generally limited to middle-aged or hypertensive populations. This study examined cross-sectional associations between BP and dietary intake of PUFAs in 814 adolescents aged 13-15 years participating in the Western Australian Pregnancy Cohort (Raine) Study. Fatty acid intakes were assessed using 3-day diet records and resting BP was determined using multiple oscillometric readings. In multivariate regression models, systolic BP was inversely associated with intakes of polyunsaturated (b=-0.436, P<0.01), omega-3 (b=-2.47, P=0.02), omega-6 (b=-0.362, P=0.04) and long chain omega-3 fatty acids (b=-4.37, P=0.04) in boys. Diastolic BP and mean arterial pressure were inversely associated with intakes of long chain omega-3 fatty acids in boys (b=-3.93, P=0.01, b=-4.05, P=0.01, respectively). For specific long-chain omega-3s, significant inverse associations were observed between eicosapentaenoic acid (EPA) and docosahexaenoic acid, such as systolic BP decreasing by 4.7 mm Hg (95% CI -9.3 to -0.1) for a quarter gram increase in EPA, but no significant associations were observed with docosapentaenoic acid. No significant associations were observed in girls, or with the omega-6 to omega-3 ratio. Our results suggest that gender may moderate relationships between fatty acid intake and BP in adolescence.

The Biology of Isolated Chromatin: Chromosomes, biologically active in the test tube, provide a powerful tool for the study of gene action

The isolated chromatin of higher organisms possesses several properties characteristic of the same chromatin in life. These include the presence of histone bound to DNA, the state of repression of the genetic material, and the ability to serve as template for the readout of the derepressed portion of the genome by RNA polymerase. The important respect in which isolated chromatin differs from the material in vivo, fragmentation of DNA into pieces shorter (5 x 10(6) to 20 x 10(6) molecular weight) than the original, does not appear to importantly alter such transcription. The study of isolated chromatin has already revealed the material basis of the restriction of template activity; it is the formation of a complex between histone and DNA. Chromatin isolated by the methods now available, together with the basis provided by our present knowledge of chromatin biochemistry and biophysics, should make possible and indeed assure rapid increase in our knowledge of chromosomal structure and of all aspects of the control of gene activity and hence of developmental processes.

Dietary glycaemic carbohydrate in relation to the metabolic syndrome in adolescents: comparison of different metabolic syndrome definitions

AIMS

High dietary glycaemic carbohydrate, as measured by the dietary glycaemic index and glycaemic load has been associated with increased risk of the metabolic syndrome in adults, but limited research exists for younger populations. We aimed to evaluate associations between dietary glycaemic carbohydrate and insulin resistance or the prevalence of the metabolic syndrome defined by three different criteria in a population-based adolescent cohort.

METHODS

Diet was assessed using 3 day food records in 769 adolescents aged 13-15 years participating in the Western Australian Pregnancy Cohort (Raine) Study. The metabolic syndrome was identified using age-specific adolescent definitions from the International Diabetes Federation, the National Cholesterol Education Program Adult Treatment Panel III and a population-derived 'high-risk' metabolic cluster algorithm. Presence of a high waist circumference was mandatory only in the International Diabetes Federation definition. Insulin resistance was measured using homeostasis model assessment (HOMA-IR).

RESULTS

The prevalence of the metabolic syndrome as defined by the International Diabetes Federation and the Adult Treatment Panel III was 3.6 and 4.0%, respectively; 25.9% of subjects were classified into the high-risk cluster. Significantly increased odds of International Diabetes Federation-defined metabolic syndrome were independently associated with a 20 unit glycaemic load increase (odds ratio 2.18; 95% confidence interval 1.26-3.78) and a 30 g carbohydrate increase (odds ratio 3.86; 95% confidence interval 1.80-8.28). No significant associations were observed when using the Adult Treatment Panel III, or the cluster-defined metabolic syndrome, or with HOMA-IR.

CONCLUSIONS

This study supports the concept that high dietary glycaemic carbohydrate is associated with a higher prevalence of the metabolic syndrome in adolescents. However, relationships vary according to the definition of the metabolic syndrome used, with waist circumference a potentially relevant factor.

Perinatal and childhood origins of cardiovascular disease

BACKGROUND

Features of the metabolic syndrome comprise a major risk for cardiovascular disease and will increase in prevalence with rising childhood obesity. We sought to identify early life influences on development of obesity, hypertension and dyslipidemia in children.

METHODS AND RESULTS

Cluster analysis was used on a subset of a longitudinal Australian birth cohort who had blood samples at age 8 (n=406). A quarter of these 8-year-olds fell into a cluster with higher body mass index, blood pressure (BP), more adverse lipid profile and a trend to higher serum glucose resembling adult metabolic syndrome. There was a U-shaped relationship between percentage of expected birth weight (PEBW) and likelihood of being in the high-risk cluster. The high-risk cluster had elevated BP and weight as early as 1 and 3 years old. Increased likelihood of the high-risk cluster group occurred with greatest weight gain from 1 to 8 years old (odds ratio (OR)=1.4, 95% confidence interval (CI)=1.3-1.5/kg) and if mothers smoked during pregnancy (OR=1.82, CI=1.05-3.2). Risk was lower if children were breast fed for >/=4 months (OR=0.6, 95% CI=0.37-0.97). Newborns in the upper two quintiles for PEBW born to mothers who smoked throughout pregnancy were at greatest risk (OR=14.0, 95% CI=3.8-51.1) compared to the nadir PEBW quintile of non-smokers.

CONCLUSION

A U-shaped relationship between birth weight and several components of the metabolic syndrome was confirmed in a contemporary, well-nourished Western population of full-term newborns, but post-natal weight gain was the dominant factor associated with the high-risk cluster. There was a prominence of higher as well as lowest birth weights in those at risk. Future health programs should focus on both pre- and post-natal factors (reducing excess childhood weight gain and smoking during pregnancy), and possibly the greatest benefits may arise from targeting the heaviest, as well as lightest newborns, especially with a history of maternal smoking during pregnancy.

The treatment of large (>70 degrees) thoracic idiopathic scoliosis curves with posterior instrumentation and arthrodesis: when is anterior release indicated?

STUDY DESIGN

Retrospective clinical study from 2 centers.

OBJECTIVE

To analyze the efficacy of posterior instrumentation and arthrodesis for thoracic idiopathic scoliosis curves more than 70 degrees.

SUMMARY OF BACKGROUND INFORMATION

The increasing use of thoracoscopic techniques in deformity surgery has led several investigators to advocate anterior release followed by posterior instrumentation when treating "stiff" thoracic curves 60 degrees-70 degrees. To our knowledge, no study has been published to define indications for anterior surgery in thoracic idiopathic scoliosis.

METHODS

This is a retrospective review of patients 20 years and younger, with idiopathic scoliosis and thoracic curves more than 70 degrees treated with isolated posterior instrumentation and arthrodesis at 2 institutions from 1989 to 1999. A total of 50 patients were identified, and 46 were available for minimum 2-year radiographic follow-up. Of the 50 patients, 44 had bend films taken before surgery. All patients were treated with third-generation segmental spinal instrumentation using a varied combination of hooks, wires, and screws.

RESULTS

Average patient age at surgery was 14.4 years (range 10-20), and average radiographic follow-up was 4.4 years (range 2-11.5). Average preoperative thoracic curve was 75 degrees (range 70 degrees-88 degrees), and average bend was 47 degrees (range 28 degrees-60 degrees), a flexibility of 37%. Average postoperative curve was 25 degrees (range 10 degrees-46 degrees), and it was 27 degrees (range 11 degrees-46 degrees) at latest follow-up, a correction of 64%. The average length of surgery was 6.15 hours, mean hospital stay was 8 days, and average blood loss was 1100 cc. The Scoliosis Research Society 22 or 24 was available at a minimum of 2 years in 46 of 50 patients. Mean domain scores were: pain 4.4, self-image 4.3, function 4.3, mental health 4.3, satisfaction 4.7, and total 4.4. Complications included 1 pseudarthrosis, 1 implant removal for prominence, and 1 implant removal for late operative site pain.

CONCLUSION

Using posterior surgery only, we have been able to at least equal the results reported in the literature by investigators using combined approaches. Isolated posterior instrumentation and arthrodesis achieve satisfactory cosmetic, radiographic, and patient-based outcomes in adolescents with idiopathic scoliosis with thoracic curves 70 degrees-90 degrees, without the added expense and morbidity of anterior release.

Using a finite element model to evaluate human injuries application to the HUMOS model in whiplash situation

STUDY DESIGN

In the field of numerical simulation, the finite element method provides a virtual tool to study human tolerance and postulate on potential trauma under crash situations, particularly in case of whiplash trauma.

OBJECTIVES

To show how medical and biomechanical interpretations of numerical simulation can be used to postulate on human injuries during crash situations. This methodology was applied to whiplash trauma analysis. A detailed analysis of kinematics of joints, stress level in hard tissues, and strain level in soft tissues was used to postulate on chronology and patterns of injury. Data were compared with published biomechanical and clinical studies of whiplash.

SUMMARY OF BACKGROUND DATA

Although many in vitro and in vivo studies have been conducted to investigate whiplash cervical injury, and despite the number of finite element models developed to simulate the biomechanical behavior of the cervical spine, to date, there are only limited finite element models reported in the literature on the biomechanical response of the whole cervical spine in these respects.

METHODS

A complete finite element model of the human body (HUMOS) build in a sitting position in a car environment was created to investigate injury mechanisms and to provide data for automotive safety improvements. It includes approximately 50,000 elements, including descriptions of all bones, ligaments, tendons, skin, muscles, and internal organs. A 15-g whiplash injury was simulated with the HUMOS model. The model predicted cervical motion segment kinematics, deformations of disks and ligaments, and stresses in bone. Model output was then compared with experimental and clinical whiplash literature.

RESULTS

In term of kinematics during the chronology of whiplash, two injury phases were identified: the first was hyperextension of the lower cervical spine (C6-C7 and C5-C6) and mild flexion of the upper cervical spine(C0-C4). The amount of upper cervical flexion was 15 degrees from C0 to C4. The second phase was hyperextension of the entire cervical spine. Potential patterns of ligamentous injuries were observed; the anterior longitudinal ligament experienced the most strain (30%) at the lower cervical spine at the time of lower cervical extension and the interspinous ligament experienced the most strain (60%) at the time of upper cervical flexion. Von Mises stresses in bone do not exceed 15 Mpa, which is largely under injury levels reported in the literature. CONCLUSIONS.: This study reports a methodology to describe and postulate on human injuries based on finite element model analysis. The output of the HUMOS model in the context of whiplash shows a strong correlation with clinical and experimental reported data. HUMOS shows promise for the modeling of other types of trauma as well.

Feed thickener for newborn infants with gastro-oesophageal reflux

BACKGROUND

Gastro-oesophageal reflux (GOR) is common in newborn infants. A common first line management is the use of feed thickeners.

OBJECTIVES

In newborn infants with GOR, to evaluate the use of feed thickeners in reducing signs and symptoms of GOR, acid episodes on pH monitoring and histological evidence of oesophagitis.

SEARCH STRATEGY

We searched MEDLINE from 1966 to December 2001, the Cochrane Controlled Trials Register, The Cochrane Library, Issue 1, 2002. CINAHL from 1982 to December 2001, and conference and symposia proceedings published in Pediatric Research 1990 to 1994. We also searched conference proceedings for the European Society for Paediatric Gastroenterology and Nutrition (ESPGAN) and the North American Society for Pediatric Gastroenterology and Nutrition (NASPGAN) from 1994 to December 2001. We did not restrict the searches to the English language.

SELECTION CRITERIA

All randomised controlled trials that examine the effects of thickening formulas on treating gastro-oesophageal reflux in neonates. The eligible studies were to compare thickened feeds to no intervention (unthickened feeds).

DATA COLLECTION AND ANALYSIS

Two independent reviewers identified potential studies from the literature search. Quality was independently assessed by two independent reviewers.

MAIN RESULTS

No studies fulfilled the requirements for inclusion in the systematic review.

REVIEWER'S CONCLUSIONS

There is no evidence from randomised controlled trials to support or refute the efficacy of feed thickeners in newborn infants with GOR. Given the absence of evidence, we cannot recommend using thickening agents for management of GOR in newborn infants.

Tetra-O-methyl nordihydroguaiaretic acid induces G2 arrest in mammalian cells and exhibits tumoricidal activity in vivo

The transcription inhibitor tetra-O-methyl nordihydroguaiaretic acid (M4N) was found to arrest the proliferation of C3, C33a, CEM-T4, and TC-1 cells in culture at the G2 stage of the cell cycle. Investigation into the mechanism of arrest revealed that M4N reduces mRNA levels and subsequent protein production of the cyclin-dependent kinase CDC2, resulting in the inactivation of the CDC2/cyclin B complex (maturation promoting factor). When injected intratumorally in a C3-cell induced C57bl/6 mouse tumor model system, M4N demonstrated substantial tumoricidal activity that correlated with a reduction in tumor cell CDC2 protein levels. These findings suggest that M4N may be a useful chemotherapeutic agent for the control of unregulated cellular proliferation.

Cluster of genes encoding the major egg envelope protein of zebrafish

The proteins of fish egg envelopes are encoded by genes that are closely related to the genes for human zona pellucida proteins. A cluster of three genes coding for an egg envelope protein was isolated from the zebrafish, Danio rerio. The three genes, zp2a, zp2b, and zp2c, are located within an 11 kb region and are each comprised of eight exons spanning 1.85 kb. The exon-intron structures of the genes are nearly identical; however, their deduced amino acid sequences diverge at exon 7 (zp2b and zp2c from zp2a) and exon 8 (zp2c from zp2b). Exons 2-7 have a structural organization similar to exons in the carboxy-terminal half of the human zona pellucida ZP1, ZP2, and ZPB genes, suggesting they arose from a common ancestral gene. Sequence comparisons indicate that the deduced zebrafish proteins are most closely related to human ZPB. Zebrafish mRNAs coding for each of the three ZP2 variants have been found either as full-length cDNAs or expressed sequence tags. Distinct from the wf(female) gene of winter flounder which we first reported (Lyons et al., 1993: J Biol Chem 268:21351-21358), expression of the zebrafish zp2 genes was found to be ovary-specific, instead of liver-specific, and the promoter regions of zp2a and zp2b, while different, both contained E-box sequences (CANNTG) that have been demonstrated to be essential for coordination of zona pellucida gene expression in mammalian oocytes. Mixed peptide sequence analysis was used to identify the major polypeptide component of isolated zebrafish egg envelopes as the zp2 gene product.

Equivalence of single and incremental subfailure stretches of rabbit anterior cruciate ligament

Experimental models are often used in the laboratory to produce incomplete soft-tissue injuries simulating those observed clinically. Single and incremental stretch protocols have been utilized. The latter has many advantages over the former. This study was designed to determine if incremental and single ligamentous stretches are biomechanically equivalent. Eleven paired fresh rabbit bone-anterior cruciate ligament-bone preparations were used. One of each pair (single-stretch protocol) was stretched to 88% of the average failure deformation and then stretched to failure. The other ligament (incremental-stretch protocol) was stretched to 55, 66, 77, and 88% of the average failure deformation and then stretched to failure. All stretches were performed at 1.2 m/sec. Stress-relaxation tests were performed before and after the 88% stretch for both stretch protocols. Relaxation curves were parameterized as forces at six time points and were also fitted to a three-element model. Load-deformation curves recorded during stretch to failure were characterized by eight parameters. Each incremental stretch step produced a significant increase in deformation, indicating alteration in the mechanical properties of the ligament. Both groups of ligaments, when intact, exhibited no differences in relaxation curves (p > 0.2). The 88% stretches, produced by each of the two stretch protocols, significantly altered the viscoelastic behavior of the ligaments (p < 0.002). However, after the 88% stretch, there were no differences in either viscoelastic (p > 0.1) or load-deformation (p > 0.1) parameters of the two stretch protocols. In conclusion, the 88% subfailure stretch significantly altered the mechanical properties of ligament, and the incremental and single stretches were biomechanically equivalent.

Prevalence and pattern of childhood abdominal pain in an Australian general practice

OBJECTIVE

Abdominal pain is a common problem in childhood and accounts for a significant workload in general practice. The aim of this study was assess the nature of abdominal pain in a sample of Australian children attending a Western Australian general practice for any reason, and to determine factors associated with the reporting of such pain.

METHODOLOGY

A prospective study of children and their families attending a rural general practice was undertaken using a parental survey to assess the frequency and nature of abdominal pain, demographic features, physical and behavioural characteristics.

RESULTS

Abdominal pain was common in this population; 44% (70 of 164) of parents reported that the index child had experienced abdominal pain in the past 12 months. The average age of children who experienced recent abdominal pain was 9 years and 9 months. Multivariate analysis suggested that children experiencing abdominal pain in the preceding 12 months were more likely to be anxious (odds ratio (OR) = 3.74, P = 0.01), to have a family history of similar problems in siblings (OR = 4.26, P = 0.01) and to experience sleep disturbance (OR = 3.90, P = 0.02) than children without abdominal pain. Consumption of three or more serves of wholemeal bread or cereals per day had a significant protective effect on reported abdominal pain in children (OR = 0.12, P = 0.03). The majority of families (66%) dealt with the pain without resorting to medical care.

CONCLUSIONS

Abdominal pain remains a common problem of children attending an Australian general practice, and was associated with features suggesting that it is related to anxiety and coping ability. Abdominal pain is not usually associated with disease; most families recognize this and cope with abdominal pain without medical consultation.

Inhibition of human papillomavirus type 16 gene expression by nordihydroguaiaretic acid plant lignan derivatives

Several methylated derivatives of a plant lignan, nordihydroguaiaretic acid (NDGA) were found to be potent anti-viral agents by suppressing Sp1 regulated transcription within the sexually transmitted viruses human immunodeficiency virus (HIV) and herpes simplex virus (HSV). A prominent Sp1 DNA binding site within many human papillomavirus (HPV) promoters has been noted to play an active role in HPV gene expression. In this report it is shown that the three NDGA derivatives, Mal.4, M(4)N, and tetra-acetyl NDGA can also inhibit gene expression from the early promoter P(97) of HPV16. The drug activity on gene expression was measured after DNA transfection of recombinant vector constructs linking the viral promoter and enhancer elements to the luciferase reporter gene. Using the specific luciferase activity as the indicator of gene expression, Mal.4 and M(4)N were found to be active in a dose dependent manner that is in the same range of concentrations reported for the promoters of HIV, HSV, and simian virus 40 (SV40) while tetra-acetyl NDGA was much more active in suppression of the HPV P(97) promoter activity than Mal.4 and M(4)N. The drugs showed limited to no effect on gene expression driven by the adenovirus major late promoter and the cytomegalovirus (CMV) promoter. Hence, such drug derivatives may be significant in the therapy of papillomavirus infections and their associated induced human cancers.

Cost-benefit analysis potential in feeding behavior of a predatory snail by integration of hunger, taste, and pain

Hunger/satiation state interacts with appetitive and noxious stimuli to determine feeding and avoidance responses. In the predatory marine snail Pleurobranchaea californica, food chemostimuli induced proboscis extension and biting at concentration thresholds that varied directly with satiation state. However, food stimuli also tended to elicit avoidance behavior (withdrawal and avoidance turns) at concentration thresholds that were relatively low and fixed. When the feeding threshold for active feeding (proboscis extension with biting) was exceeded, ongoing avoidance and locomotion were interrupted and suppressed. Noxious chemostimuli usually stimulated avoidance, but, in animals with lower feeding thresholds for food stimuli, they often elicited feeding behavior. Thus, sensory pathways mediating appetitive and noxious stimuli may have dual access to neural networks of feeding and avoidance behavior, but their final effects are regulated by satiation state. These observations suggest that a simple cost-benefit computation regulates behavioral switching in the animal's foraging behavior, where food stimuli above or below the incentive level for feeding tend to induce feeding or avoidance, respectively. This decision mechanism can weigh the animal's need for nutrients against the potential risk from other predators and the cost of relative energy outlay in an attack on prey. Stimulation of orienting and attack by low-level noxious stimuli in the hungriest animals may reflect risk-taking that can enhance prey capture success. A simple, hedonically structured neural network model captures this computation.

Inhibition of Na(+) current by diphenhydramine and other diphenyl compounds: molecular determinants of selective binding to the inactivated channels

Diphenhydramine is an H1 histamine receptor antagonist, yet it also has a clinically useful local anesthetic effect. We found that diphenhydramine inhibits the neuronal Na(+) current, and the inhibition is stronger with more positive holding potentials. The dissociation constant between diphenhydramine and the inactivated Na(+) channel is approximately 10 microM, whereas the dissociation constant between diphenhydramine and the resting channel is more than 300 microM. The local anesthetic effect of diphenhydramine thus is ascribable to inhibition of Na(+) current by selective binding of the drug to the inactivated channels. Most interestingly, many other compounds, such as the anti-inflammatory drug diclofenac, the anticonvulsant drug phenytoin, the antidepressant drug imipramine, and the anticholinergic drug benztropine, have similar effects on neuronal Na(+) current. There is no apparent common motif in the chemical structure of these compounds, except that they all contain two phenyl groups. Molecular modeling further shows that the two benzene rings in all these drugs have very similar spatial orientations (stem bond angle, approximately 110 degrees; center-center distance, approximately 5 A). In contrast, the two phenyl groups in phenylbutazone, a drug that has only a slight effect on Na(+) current, are oriented in quite a different way. These findings strongly suggest that the two phenyl groups are the key ligands interacting with the channel. Because the binding counterpart of a benzene ring usually is also a benzene ring, some aromatic side chain groups of the Na(+) channel presumably are realigned during the gating process to make the very different affinity to the aforementioned drugs between the inactivated and the resting channels.

Isolation and characterization of IPP, a novel human gene encoding an actin-binding, kelch-like protein

The kelch family of proteins is defined by a 50 amino-acid repeat that has been shown to associate with actin. Here we describe the cloning and initial characterization of IPP, a novel human gene that predicts a kelch family protein homologous to the mouse Ipp gene, a previously described kelch family member. A 3kb IPP cDNA clone was isolated from a human placenta library using a probe derived from Ipp. Restriction mapping and Southern blot analysis show that IPP comprises eight exons spanning more than 47kb of genomic DNA. Fluorescence in situ hybridization maps the gene to chromosome 1p32-1p34. Northern blot analysis reveals transcripts of 1.4, 2.2, 5. 0, and 7.3kb. The 1.4 and 2.2kb messages are found exclusively in testis, while the 5.0 and 7.3kb messages are expressed at varying levels in ovary, placenta, small intestine, spleen, testis, and thymus. The IPP cDNA clone contains a 1752bp open reading frame that predicts a 584 amino-acid, 66kDa protein. Sequence analysis indicates an N-terminal POZ protein-protein interaction domain and a C-terminal kelch repeat domain consisting of six tandemly arranged repeats. Cosedimentation assays performed with these domains expressed as glutathione S-transferase fusion proteins demonstrate an actin-binding activity mediated specifically by the kelch repeat domain of IPP.

Voltage- and use-dependent inhibition by amphetamine of field potentials and Na+ current in rat nucleus accumbens neurons

The psychostimulant amphetamine (AMPH) is known to act as an indirect dopamine agonist by promoting dopamine release. Here we demonstrate direct AMPH inhibition of field potentials and Na+ currents in rat nucleus accumbens (NAc) neurons. The experiments were done with field potential recordings from NAc slices and whole-cell recordings from isolated NAc neurons. In NAc slices, AMPH inhibited the field potentials. The inhibition increased when the NAc neurons were depolarized with higher extracellular K+ or when the field potentials were evoked at a higher rate. In isolated NAc neurons, AMPH inhibited the Na+ currents. The inhibition increased when Na+ currents were activated from more depolarized holding potentials or were activated more frequently. The voltage- and use-dependent inhibition of field potentials and Na+ currents by AMPH suggests a similar mechanism of AMPH action with local anesthetics and antiarrhythmic drugs.

Antiviral activities of methylated nordihydroguaiaretic acids. 2. Targeting herpes simplex virus replication by the mutation insensitive transcription inhibitor tetra-O-methyl-NDGA

We had previously reported that tetramethyl-O-NGDA (M4N), a synthetic derivative of the naturally occurring nordihydroguaiaretic acid (NDGA), is able to inhibit HIV Tat transactivation by blocking host Sp1 protein at the Sp1 cognate binding site on the HIV LTR promoter. The present studies were undertaken to examine whether M4N is able to inhibit the replication of herpes simplex virus (HSV), another Sp1-regulated virus. The results showed that in Vero cells, M4N inhibits at micromolar levels (IC50 = 43.5 microM) the expression of the herpes immediate early gene (alpha-ICP4), which is essential for HSV replication. An electrophoretic mobility shift assay, examining Sp1 binding to the alpha-ICP4 promoter, showed a significant inhibition of the control bands: 88% inhibition of the fast moving band (FMB) and 45% of the slow moving band (SMB), at 100 microM of drug concentration. Comparative studies between M4N and acycloguanosine (acyclovir, ACV) in cultured Vero cells revealed an interesting pattern in the drug sensitivity (IC50) and cytotoxicity (TC50) parameters. For M4N, the IC50 varied between 11.7 and 4 microM in 10 passages of HSV-1 and 4 passages of HSV-2 with no indication for a requirement of higher drug concentration. In contrast, for acyclovir, the IC50 increased from 7 microM in the first passage to 444 microM in the tenth passage of HSV-1, and >88 microM for the fourth passage of HSV-2, indicating a rapid build-up of drug resistance against acyclovir. While the selective index (SI), defined as the ratio: TC50/IC50, remained relatively constant for M4N; it dropped 60-fold for acyclovir in the endpoints of viral passages. Drug sensitivity for M4N toward the acyclovir-sensitive strain (sm44) and the acyclovir-resistant strain (ACV-10) of HSV-1 was similar, indicating no cross-resistance between M4N and acyclovir in their anti-HSV effects. These results may have an important clinical relevance since HSV has been shown to be a factor for spreading of HIV.

Antiviral activities of methylated nordihydroguaiaretic acids. 1. Synthesis, structure identification, and inhibition of tat-regulated HIV transactivation

Nordihydroguaiaretic acid (NDGA, meso-1) possesses four phenolic hydroxyl groups. Treatment of NDGA with 0.50-4.1 equiv of dimethyl sulfate and 3.0-6.0 equiv of potassium carbonate in acetone at 56 degrees C gave nine methylated products. Eight of those mono-, di-, tri-, and tetra-O-methylated NDGAs were isolated in pure form, and their structures were identified unambiguously by spectroscopic methods. A preparative amount of tetramethyl NDGA M4N (10) was obtained in 99% yield from NDGA by use of 4.1 equiv of dimethyl sulfate for the methylation. Among the eight different methylated NDGAs (2-6 and 8-10), tetra-O-methyl-NDGA (10) showed the strongest anti-HIV activity (IC50 11 microM). Chemically synthesized 3'-O-methyl-NDGA ((+/-)-2) showed identical anti-HIV activity (IC50 25 microM) to the lignan isolated from Creosote Bush. Lignans with methylated catecholic hydroxyl groups can be produced in large quantities with low cost. At drug concentrations below 30 microM tetramethyl NDGA (10) was a stronger anti-HIV agent than mono- and dimethylated NDGAs.

L-myc, GST M1 genetic polymorphism and hepatocellular carcinoma risk among chronic hepatitis B carriers

In order to assess associations between the genetic polymorphism of L-myc and glutathione S-transferase M1 (GST M1) and the risk of hepatocellular carcinoma (HCC), a total of 46 surgically treated HCC patients who were seropositive in hepatitis B surface antigen (HBsAg) and 88 HBs-Ag positive controls were recruited for this study. L-myc and GST M1 genetic polymorphism was examined using a polymerase chain reaction-based restriction fragment length polymorphism assay on DNA extracted from liver and peripheral blood samples. There was no significant difference in GST M1 genotypes between HCC patients and matched controls. A gene dosage trend of association with HCC risk was observed for L-myc genotype. The dose-response relationship remained statistically significant in the multiple logistic regression analysis.

Isolation of anti-HIV-1 lignans from Larrea tridentata by counter-current chromatography

Several lignans, mostly new, were isolated from Larrea tridentata by assay-guided counter-current chromatography (CCC). Using the secreted alkaline phosphatase bioassay of HIV Tat transactivation and the two-phase hexane-ethyl acetate-methanol-water solvent system, two major components (Gr and Lo) were identified as anti-HIV active principles. The chemical structures of the constituents of Gr (G1-G4) and Lo (L1-L4) were determined by GC-MS and NMR. After optimization of isolation conditions, a large-scale isolation with the chloroform-methanol-water system yielded five constituents (FB1-FB5). The most predominant anti-HIV compound FB2 (denoted Malachi 4:5-6 or mal.4), which occurs in 0.23% yield, was separated from its FB1 isomer (0.13% yield). Compound FB4 and two tricyclic lignans (FB3 and FB5) were also isolated in a substantial amount for further testing of their anti-HIV activities. These compounds may represent a new class of anti-HIV agents with important clinical relevance.

Inhibition of human immunodeficiency virus type 1 transcription and replication by DNA sequence-selective plant lignans

A plant lignan, 3'-O-methyl nordihydroguaiaretic acid (3'-O-methyl NDGA, denoted Malachi 4:5-6 or Mal.4; molecular weigth 316), was isolated from Larrea tridentata and found to be able to inhibit human immunodeficiency virus (HIV) Tat-regulated transactivation in vivo, induce protection of lymphoblastoid CEM-SS cells from HIV (strain IIIB) killing, and suppress the replication of five HIV-1 strains (WM, MN, VS, JR-CSF, and IIIB) in mitogen-stimulated peripheral blood mononuclear cells, all in a dose-dependent manner. Mal.4 inhibits both basal transcription and Tat-regulated transactivation in vitro. The target of Mal.4 has been localized to nucleotides -87 to -40 of the HIV long terminal repeat. Mal.4 directly and specifically interferes with the binding of Sp1 to Sp1 sites in the HIV long terminal repeat. By inhibiting proviral expression, Mal.4 may be able to interrupt the life cycles of both wild-type and reverse transcriptase or protease mutant viruses in HIV-infected patients.

Novel pharmacological properties of transient potassium currents in central neurons revealed by N-bromoacetamide and other chemical modifiers

The chemical modifiers N-bromoacetamide (NBA), N-bromosuccinimide (NBS), and chloramine-T (ChT) are commonly used to remove fast inactivation of sodium currents and transient potassium currents (IA). In the present study, I examined the effects of these chemical modifiers as well as of others on IA in neurons dissociated from several brain regions. External application of NBA irreversibly inhibited IA, with higher NBA concentrations increasing the rate of inhibition. The current kinetics, however, were not altered by external NBA at any concentration. IA was also inhibited by internal NBA but only at high concentrations, and the rate of inhibition was much slower. The current kinetics were not altered by internal NBA at any concentration. NBA is a nonspecific chemical reagent that can modify a protein at several target amino acids. The NBA-induced irreversible inhibition of IA was reproduced by external diethylpyrocarbonate, a reagent that specifically modifies histidine residues, and by ChT and cyanogen bromide, reagents that modify methionine residues through distinct mechanisms. However, NBS, a reagent that cleaves the peptide bond at tryptophan residues, had no effect on IA, nor did chemical modifiers specific for cysteine and tyrosine residues. Taken together, these results suggest that the conserved, functionally important methionine and/or histidine residues are the likely targets for NBA modifications. These novel pharmacological properties are in sharp contrast to those known previously, despite their similarity in both kinetics and 4-AP sensitivities. Therefore, the pharmacological treatments presented in the present study should be useful for characterizing other IA.

Mutational analysis of neurokinin receptor function

The interactions of the NK1 receptor with peptide agonists or nonpeptide antagonists have been investigated by site-directed mutagenesis and computer modeling. At least 10 residues in the extracellular and transmembrane regions of the receptor are required for the binding of many peptide agonists. The C-terminal amide of peptide agonists is likely to be bound near Asn-85. Residues likely to be involved in the subsequent receptor activation include Glu-78 and Tyr-205. The binding site for nonpeptide antagonists can be defined by at least five residues in transmembrane helices 4-7, and primary contacts between key residues and quinuclidine antagonists have been assigned based on CP-96,345 and its analogs. Analyses of the wild-type and mutant NK1 and NK2 receptors, intact and truncated peptides, and various antagonists suggest that the agonist and antagonist binding sites overlap spatially, even though agonists and antagonists do not interact with the same set of residues on the receptor. Mapping the ligand binding site not only allows us to better understand the ligand--receptor interaction and antagonism but also leads to a refined three-dimensional model of the NK1 receptor.

Inhibition of replication of human respiratory syncytial virus by 6-diazo-5-oxo-L-norleucine

The effect of 6-diazo-5-oxo-L-norleucine (L-DON), a glutamine analog, on RSV replication was studied. At a concentration of 0.01 mM L-DON, 99% of RSV replication in treated CV-1 cells was inhibited. At this concentration of L-DON, the level of cellular protein synthesis was identical to untreated control cells. Trypan blue staining revealed that all the cells remained viable even at concentrations of L-DON as high as 10 mM. In addition, L-DON added as late as 24 h post infection can effectively suppress viral replication. Analysis of viral mRNA levels by Northern blot revealed that secondary transcription and subsequent steps in the virus life cycle were inhibited. Immunoprecipitation of viral proteins from drug treated or untreated cultures showed that synthesis of all viral proteins was drastically reduced by L-DON, with a slightly greater inhibition of viral glycoproteins. Furthermore, immunofluorescent staining showed that drug treated cells expressed both F and N proteins and that F was inserted into the membrane as the native F protein.