Influence of machine-based puffing parameters on aerosol and smoke emissions from next generation nicotine inhalation products.

There is increasing diversity of nicotine inhalation products worldwide. Next Generation Products (NGP) such as e-cigarettes, have gained mass popularity, and there is increasing use of electrical and carbon-based Tobacco-Heating Products (e-THP and c-THP respectively). Recently, emission levels from these products have been compared to conventional cigarettes (CC); however, few formal laboratory testing standards exist, and inconsistent puffing parameters have been used. We investigated the impact of how a number of NGPs, including two e-cigarettes, a carbon-heated THP, and both pulse- and continuously-heated e-THPs, are puffed on the magnitude of their emissions, examining the influence of puff profile, volume, frequency and duration, in comparison to standard CCs. Our findings demonstrated that for each NGP choice of puffing parameters has a substantial impact on the magnitude of aerosol and smoke emissions, and that significant differences exist between different types of NGP. With e-cigarettes and pulse-heated e-THPs puff duration is the most important puffing parameter influencing yields. In contrast, for CCs, c-THPs and continuously-heated e-THPs, puff volume and puff frequency were the critical parameters. For e-cigarettes, there was no significant difference in emissions between rectangular and bell-shaped profiles. Our study has also shown that these different behaviours are a result of how heat-management within different NGPs, from heat-source to the nicotine- and aerosol-releasing substrates, is a vital mechanistic factor impacting aerosol generation. These findings point the need for detailed real-world e-cigarette and THP puffing topography data in order to identify the most appropriate puffing parameters for laboratory testing; our findings will help focus these studies on the most important parameters and can thereby support the future development of robust standardised NGP testing regimes.

Perimortem caesarean deliveries.

Although cardiac arrest in pregnancy is rare, it is important that all individuals involved in the acute care of pregnant women are suitably trained, because the outcome for both mother and fetus can be affected by the management of the arrest. Perimortem caesarean delivery was first described in 715 BC. Initially the procedure was performed principally for religious or political reasons. Although the potential for fetal survival was proposed, it was rarely successful, probably because the delivery was delayed until maternal death was established. However, in recent decades, case reports have suggested improved maternal as well as fetal survival if perimortem caesarean section was performed rapidly once maternal arrest has occurred. While evidence for this is largely based on case reports, the physiological advantages including removing inferior caval obstruction, and hence improving venous return to the heart, reducing oxygen requirement and improving chest compliance appear compelling. Factors that reduce errors and minimise the delay in performance of caesarean delivery are discussed, in particular the importance of training, organizational factors within a hospital and the use of prompts during an arrest. While evidence is limited, it is probable that both maternal and fetal survival are improved with early delivery by perimortem caesarean delivery. More importantly, no evidence was found from case report reviews that either maternal or fetal survival was worsened. Perimortem caesarean delivery therefore remains a key consideration in the management of maternal arrest from the mid second trimester.

Variation in tobacco and mainstream smoke toxicant yields from selected commercial cigarette products.

There is a drive toward the mandated lowering and reporting of selected toxicants in tobacco smoke. Several studies have quantified the mainstream cigarette emissions of toxicants, providing benchmark levels. Few, however, have examined how measured toxicant levels within a single product vary over time due to natural variation in the tobacco, manufacturing and measurement. In a single centre analysis, key toxicants were measured in the tobacco blend and smoke of 3R4F reference cigarette and three commercial products, each sampled monthly for 10 months. For most analytes, monthly variation was low (coefficient of variation <15%); but higher (⩾ 20%) for some compounds present at low (ppb) levels. Reporting toxicant emissions as a ratio to nicotine increased the monthly variation of the 9 analytes proposed for mandated lowering, by 1-2 percentage points. Variation in toxicant levels was generally 1.5-1.7-fold higher in commercial cigarettes compared with 3R4F over the 10-month period, but increased up to 3.5-fold for analytes measured at ppb level. The potential error (2CV) associated with single-point-in-time sampling averaged ∼ 20%. Together, these data demonstrate that measurement of emissions from commercial cigarettes is associated with considerable variation for low-level toxicants. This variation would increase if the analyses were conducted in more than one laboratory.

Therapeutic strategies within the ubiquitin proteasome system.

The ubiquitin-dependent proteolysis system (UPS) is the main driver of regulated protein degradation in all eukaryotic cells, and it is becoming increasingly clear that defects within this pathway drive a large number of human pathologies. Recent success in the use of proteasome inhibitors in the treatment of hematological malignancies validates the UPS as a viable therapeutic pathway, and substantial effort is now focused on the development of both second-generation proteasome inhibitors as well as novel strategies for the inhibition of upstream UPS enzymes. In this review we discuss the potential 'druggability' of key nodes within the UPS and summarize recent advances within the field.

High intake of palatable food predicts binge-eating independent of susceptibility to obesity: an animal model of lean vs obese binge-eating and obesity with and without binge-eating.

OBJECTIVE: To determine the stability of individual differences in non-nutritive 'junk' palatable food (PF) intake in rats; assess the relationship of these differences to binge-eating characteristics and susceptibility to obesity; and evaluate the practicality of using these differences to model binge-eating and obesity. DESIGN: Binge-eating prone (BEP) and resistant (BER) groups were identified. Differential responses to stress, hunger, macronutrient-varied PFs, a diet-induced obesity (DIO) regimen and daily vs intermittent access to a PF+chow diet, were assessed. SUBJECTS: One hundred and twenty female Sprague-Dawley rats. MEASUREMENTS: Reliability of intake patterns within rats; food intake and body weight after various challenges over acute (1, 2, 4 h), 24-h and 2-week periods. RESULTS: Although BEP and BER rats did not differ in amount of chow consumed, BEPs consumed >50% more intermittent PF than BERs (P<0.001) and consistently so (alpha=0.86). BEPs suppressed chow but not PF intake when stressed, and ate as much when sated as when hungry. Conversely, BERs were more affected by stress and ate less PF, not chow, when stressed and were normally hyperphagic to energy deficit. BEP overeating generalized to other PFs varying in sucrose, fat and nutrition content. Half the rats in each group proved to be obesity prone after a no-choice high fat diet (DIO diet) but a continuous diet of PF+chow normalized the BEPs high drive for PF. CONCLUSION: Greater intermittent intake of PF predicts binge-eating independent of susceptibility to weight gain. Daily fat consumption in a nutritious source (DIO-diet; analogous to a fatty meal) promoted overeating and weight gain but limiting fat to daily non-nutritive food (PF+chow; analogous to a snack with a low fat meal), did not. The data offer an animal model of lean and obese binge-eating, and obesity with and without binge-eating that can be used to identify the unique physiology of these groups and henceforth suggest more specifically targeted treatments for binge-eating and obesity.

Bladder neck mobility is a heritable trait.

OBJECTIVE: Congenital connective tissue dysfunction may partly be responsible for female pelvic organ prolapse and urinary incontinence. We undertook a heritability study to determine whether mobility of the bladder neck, one of the main determinants of stress urinary incontinence, is genetically influenced. DESIGN: Heritability study using a twin model and structural equation modelling. SETTING: Queensland Institute of Medical Research, Brisbane, Australia. POPULATION: One hundred and seventy-eight nulliparous Caucasian female twins and their sisters (46 monozygotic pairs, 24 dizygotic pairs and 38 sisters) aged 18-24 years. METHODS: We performed translabial ultrasound, supine and after bladder emptying, for pelvic organ mobility. Urethral rotation and bladder neck descent were calculated using the best of three effective Valsalva manoeuvres. MAIN OUTCOME MEASURES: Bladder and urethral mobility on Valsalva assessed by urethral rotation, vertical and oblique bladder neck descent. RESULTS: Genetic modelling indicated that additive genes accounted for up to 59% of the variance for bladder neck descent. All remaining variance appeared due to environmental influences unique to the individual, including measurement error. CONCLUSION: A significant genetic contribution to the phenotype of bladder neck mobility appears likely.

Pelvic organ descent in young nulligravid women.

OBJECTIVE: There is little information available on what constitutes "normal" pelvic organ mobility. This study presents normal values for urethral, bladder, cervical, and rectal descent on Valsalva. STUDY DESIGN: One hundred eighteen nulligravid white women aged 18 to 24 years were recruited for a prospective observational study. Translabial ultrasound was undertaken supine and after voiding, with the most effective of at least 3 Valsalva maneuvers used for evaluation. RESULTS: Urethral rotation on Valsalva varied from 0 to +90 degrees (mean 32 degrees), bladder neck descent from 1.2 to 40.2 mm (mean 17.4 mm). The cervix descended to between 59 and 0 mm above the symphysis pubis (mean 30.8 mm); the rectal ampulla descended to between 54 mm above and 22 mm below the symphyseal margin (mean 7.8 mm). In a test-retest series, intraclass correlations were between 0.64 and 0.89, implying good-to-excellent repeatability of the ultrasound assessment. CONCLUSION: A wide range of values was obtained for all parameters. A significant congenital contribution to the phenotype of female pelvic organ prolapse appears likely.

Consumption of a controlled low-fat diet containing olestra for 9 months improves health risk factors in conjunction with weight loss in obese men: the Ole' Study.

OBJECTIVE: To compare the effects of a standard American diet, a traditional low-fat diet, and a low-fat diet containing the fat substitute olestra on risk factors for heart disease and diabetes. DESIGN: A 9-month, double-blind, randomized, parallel-arm, feeding study comparing three diets: (1). control (33% fat), (2). fat-reduced (FR; 25% fat), and (3). fat-substituted (FS) where olestra replaced 1/3 of dietary fat (33% lipid and 25% digestible fat). Subjects were allowed to adjust their total energy intake as desired, allowing weight to fluctuate. SUBJECTS: A total of 37 healthy, obese men (age 36.7+/-1.3 y; body mass index 30.8+/-0.4 kg/m(2)). MEASUREMENTS: Body weight and composition by dual-energy X-ray absorptiometry, blood pressure, serum lipids, lipoproteins, hemostatic factors, glucose, insulin, and leptin at baseline and every 3 months. RESULTS: The FS group lost 6.27 kg of body weight by 9 months vs 4.0 kg in the control and 1.79 kg in the FR groups. There was a significant diet main effect on cholesterol (P=0.002), low-density lipoprotein cholesterol (P=0.003), and triglycerides (P=0.01), all of which decreased in the FS group but not the other groups by 9 months. Apolipoprotein B (ApoB) increased in the FR and control groups but was unchanged in the FS group (diet main effect P=0.04). High-density lipoprotein (HDL) cholesterol increased in all groups over 9 months (time main effect P=0.0001). Time main effects were also observed for cholesterol, ApoA1, ApoB, Factor VII, diastolic blood pressure, and glucose. After adjustment for % fat loss at 9 months, the effects of diet on change in risk factors remained significant only for triglycerides. DISCUSSION: Consumption of a low-fat diet containing olestra for 9 months produced significant improvement in cardiovascular risk factors, an effect largely explained by weight loss. Long-term low-fat diet consumption with or without olestra does not decrease HDL cholesterol.

Increased clearance of von Willebrand factor antigen post-DDAVP in Type 1 von Willebrand disease: is it a potential pathogenic process?

The mechanism of von Willebrand factor (VWF) clearance is not fully understood. The factors that affect VWF clearance, and the normal in vivo mechanism of clearance, may be relevant to the pathogenesis of Type 1 von Willebrand disease (VWD), in which there is a partial deficiency of VWF. In order to investigate the clearance of VWF in Type 1 VWD, the current study assessed the half-life of VWF antigen (t(1/2) VWF:Ag) in Type 1 VWD patients and individuals with mild hemophilia A following the administration of 1-deamino-8-d-arginine vasopressin (DDAVP; desmopressin). To date 20 individuals have been assessed, 13 with Type 1 VWD and seven with mild hemophilia A. The median t(1/2) VWF:Ag in the Type 1 VWD and mild hemophilia A groups were 4.6 h and 9.5 h, respectively. The difference between the t(1/2) VWF:Ag for the two groups was significant, P < 0.02. Analysis of the data showed a correlation between the t(1/2) VWF:Ag and the baseline VWF:Ag level prior to administration of DDAVP: lower baseline VWF:Ag levels were associated with a shorter t(1/2) VWF:Ag. These data suggest that increased clearance of VWF may be the pathogenic mechanism in some cases of Type 1 VWD.

A role for olestra in body weight management.

Olestra is a fat substitute made from fatty acids esterified to sucrose and can be used in the preparation of virtually any food made with fat. Foods made with olestra retain the mouthfeel, palatability and satiating effects of their full-fat counterparts without providing any digestible energy. Because olestra provides no energy, it has the potential to be a useful tool in weight loss and weight maintenance. Short-term studies of olestra replacement in foods demonstrate that fat replacement leads to a net reduction in fat intake. When excess total energy is available, fat replacement also reduces total energy intake in lean and obese men and women. In longer-term studies in which olestra is incorporated into the daily diet, there is an incomplete compensation for the fat energy replaced by olestra. When overweight men consumed olestra as part of a varied diet over nine months, weight loss continued for the duration of the study, whereas individuals receiving a typical low-fat diet regained most of the initial weight lost. Other studies are underway to examine the usefulness of olestra in long-term weight maintenance following weight loss. Post-marketing surveillance of olestra foods in the United States indicates that substitution of olestra for only 1-2 g of fat d-1 may be sufficient to prevent the average weight gain reported in adults of 0.5-1.0 kg year-1.

Heritability and gene-environment interactions for melanocytic nevus density examined in a U.K. adolescent twin study.

Risk factors for melanoma include environmental (particularly ultraviolet exposure) and genetic factors. In rare families, susceptibility to melanoma is determined by high penetrance mutations in the genes CDKN2A or CDK4, with more common, less penetrant genes also postulated. A further, potent risk factor for melanoma is the presence of large numbers of melanocytic nevi so that genes controlling nevus phenotype could be such melanoma susceptibility genes. A large Australian study involving twins aged 12 y of predominantly U.K. ancestry showed strong evidence for genetic influence on nevus number and density. We carried out essentially the same study in the U.K. to gain insight into gene-environment interactions for nevi. One hundred and three monozygous (MZ) and 118 dizygous (DZ) twin pairs aged 10-18 y were examined in Yorkshire and Surrey, U.K. Nevus counts were, on average, higher in boys (mean = 98.6) than girls (83.8) (p = 0.009) and higher in Australia (110.4) than in the U.K. (79.2, adjusted to age 12 y, p < 0.0001), and nevus densities were higher on sun-exposed sites (92 per m2) than sun-protected sites (58 per m2) (p < 0.0001). Correlations in sex and age adjusted nevus density were higher in MZ pairs (0.94, 95%CI 0.92-0.96) than in DZ pairs (0.61, 95%CI 0.49-0.72), were notably similar to those of the Australian study (MZ = 0.94, DZ = 0.60), and were consistent with high heritability (65% in the U.K., 68% in Australia). We conclude that emergence of nevi in adolescents is under strong genetic control, whereas environmental exposures affect the mean number of nevi.

Triggering ubiquitination of a CDK inhibitor at origins of DNA replication.

To ensure proper timing of the G1-S transition in the cell cycle, the cyclin E-Cdk2 complex, which is responsible for the initiation of DNA replication, is restrained by the p21(Cip1)/p27(Kip1)/p57(Kip2) family of CDK (cyclin-dependent kinase) inhibitors in humans and by the related p27(Xic1) protein in Xenopus. Activation of cyclin E-Cdk2 is linked to the ubiquitination of human p27(Kip1) or Xenopus p27(Xic1) by SCF (for Skp1-Cullin-F-box protein) ubiquitin ligases. For human p27(Kip1), ubiquitination requires direct phosphorylation by cyclin E-Cdk2. We show here that Xic1 ubiquitination does not require phosphorylation by cyclin E-Cdk2, but it does require nuclear accumulation of the Xic1-cyclin E-Cdk2 complex and recruitment of this complex to chromatin by the origin-recognition complex together with Cdc6 replication preinitiation factors; it also requires an activation step necessitating cyclin E-Cdk2-kinase and SCF ubiquitin-ligase activity, and additional factors associated with mini-chromosome maintenance proteins, including the inactivation of geminin. Components of the SCF ubiquitin-ligase complex, including Skp1 and Cul1, are also recruited to chromatin through cyclin E-Cdk2 and the preinitiation complex. Thus, activation of the cyclin E-Cdk2 kinase and ubiquitin-dependent destruction of its inhibitor are spatially constrained to the site of a properly assembled preinitiation complex.

Serum concentrations of retinol, alpha-tocopherol and the carotenoids are influenced by diet, race and obesity in a sample of healthy adolescents.

An important part of understanding the functions of vitamin A, vitamin E and the carotenoids in nutritional status assessment, health promotion and disease prevention is knowledge of factors that influence their distribution in human tissues. Our objective was to examine serum concentrations of these nutrients and compounds in a sample of 285 healthy participants, 12-17 y old, from three U. S. cities. Pearson correlations between diet measured with a food frequency questionnaire and serum nutrient concentrations among these adolescents (adjusted for total serum cholesterol, age, sex, race and body mass index) were as follows: retinol, 0.23; alpha-tocopherol, 0.16; alpha-carotene, 0.31; beta-carotene, 0.15; beta-cryptoxanthin, 0.38; lycopene, 0.08; and lutein + zeaxanthin, 0.25. Multivariate linear regression modeled associations of demographic, dietary and physiologic variables with serum concentrations of these nutrients. African-American participants had significantly lower concentrations of serum retinol (P < 0.001), alpha-tocopherol (P < 0.01) and alpha-carotene (P < 0.02), but higher concentrations of lutein + zeaxanthin (P = 0.001) compared with Caucasians. Obese participants had serum nutrient concentrations that were 2-10% (P < 0.05) lower than normal weight participants. Dietary intake was a significant predictor of all serum analytes (P < 0.01) except lycopene. These models explained 20% of the variability in serum retinol, 28% of the variability in serum alpha-tocopherol, and 14-24% of the variability in serum carotenoids.

Positive-negative selection for homologous recombination in Arabidopsis.

In plants gene knock-outs and targeted mutational analyses are hampered by the inefficiency of homologous recombination. We have developed a strategy to enrich for rare events of homologous recombination in Arabidopsis using combined positive and negative selection. The T-DNA targeting construct contained two flanking regions of the target alcohol dehydrogenase gene as homologous sequences, and neomycin phosphotransferase and cytosine deaminase as positive and negative markers, respectively. A root explant transformation procedure was used to obtain transgenic calli. Among 6250 transformants isolated by positive selection, 39 were found to be resistant to negative selection as well. Of these 39, at least one had undergone homologous recombination correlated with a unidirectional transfer of information. Although the ADH locus was not changed, our data demonstrate that a homologous recombination event can be selected by positive negative selection in plants.

A brief dietary assessment instrument for assessing target foods, nutrients and eating patterns.

OBJECTIVE: To develop and validate a new dietary assessment tool, the focused recall, and to use this to measure co-consumption of carotenoid-containing fruits and vegetables with savory snacks. DESIGN: Participants completed a telephone-administered focused recall and a 24-hour recall on the same day. We compared mean estimates of fruit, vegetable, savory snack and carotenoid consumption from both instruments. We also assessed the ability of each method to measure co-consumption of carotenoids with full-fat, reduced/non-fat and olestra-containing savory snacks. SETTING AND SUBJECTS: Data are from 245 male and 244 female adult participants in the Olestra Post-Marketing Surveillance Study (OPMSS). RESULTS: The mean (=/- SD) intake of fruit was 1.8(1.1) servings day(-1) from the focused recall and 1.6 (1.4) servings day(-1) from the 24-hour recall (r=0.56). The mean vegetable intake was 2.1 (1.3) and 2.2 (1.7) servings day(-1) (r=0.42), respectively, from each instrument. Estimates of total carotenoid and beta-carotene intake were within 5% of each other (r= 0.63 for total carotenoids and r= 0.70 for beta-carotene). Both instruments estimated that approximately 14% of total daily carotenoids were co-consumed with savory snacks (r= 0.63). CONCLUSIONS: The focused recall provides valid information about fruit, vegetable and savory snack consumption and allows researchers to examine associated eating patterns more easily.

Recombinant factor IX (BeneFix) by adjusted continuous infusion: a study of stability, sterility and clinical experience.

The safety and efficacy of adjusted continuous infusion (CI) of recombinant factor IX (FIX; BeneFix) was assessed in vitro and in a clinical study. BeneFix was reconstituted at 100 IU mL-1 with or without unfractionated heparin (4 U mL-1) and stored at either 4 degrees C or room temperature. Reconstituted BeneFix retained at least 90% activity over 14 days if stored at 4 degrees C but stability was reduced at room temperature. BeneFix reconstituted in a sterile pharmacy was free of bacterial contamination. Six patients with haemophilia B received seven CIs of BeneFix to cover routine surgery and severe bleeding episodes. The CIs lasted between 3 and 10 days. In all cases, haemostasis was excellent and the desired therapeutic FIX level was easily maintained. No thrombotic episodes or inhibitor development occurred but two patients developed thrombophlebitis at the infusion site when heparin was not added to the infusion. BeneFix is not currently licensed for CI and we suggest that studies to enable licensing should be established as soon as possible.

The lore of the RINGs: substrate recognition and catalysis by ubiquitin ligases.

Recently, many new examples of E3 ubiquitin ligases or E3 enzymes have been found to regulate a host of cellular processes. These E3 enzymes direct the formation of multiubiquitin chains on specific protein substrates, and - typically - the subsequent destruction of those proteins. We discuss how the modular architecture of E3 enzymes connects one of two distinct classes of catalytic domains to a wide range of substrate-binding domains. In one catalytic class, a HECT domain transfers ubiquitin directly to substrate bound to a non-catalytic domain. Members of the other catalytic class, found in the SCF, VBC and APC complexes, use a RING finger domain to facilitate ubiquitylation. The separable substrate-recognition domains of E3 enzymes provides a flexible means of linking a conserved ubiquitylation function to potentially thousands of ubiquitylated substrates in eukaryotic cells.

The SRm160/300 splicing coactivator subunits.

The SRm160/300 splicing coactivator, which consists of the serine/arginine (SR)-related nuclear matrix protein of 160 kDa and a 300-kDa nuclear matrix antigen, functions in splicing by promoting critical interactions between splicing factors bound to pre-mRNA, including snRNPs and SR family proteins. In this article we report the isolation of a cDNA encoding the 300-kDa antigen and investigate the activity of it and SRm160 in splicing. Like SRm160, the 300-kDa antigen contains domains rich in alternating S and R residues but lacks an RNA recognition motif; the protein is accordingly named "SRm300." SRm300 also contains a novel and highly conserved N-terminal domain, several unique repeated motifs rich in S, R, and proline residues, and two very long polyserine tracts. Surprisingly, specific depletion of SRm300 does not prevent the splicing of pre-mRNAs shown previously to require SRm160/300. Addition of recombinant SRm160 alone to SRm160/300-depleted reactions specifically activates splicing. The results indicate that SRm160 may be the more critical component of the SRm160/300 coactivator in the splicing of SRm160/300-dependent pre-mRNAs.

Dietary carotenoids and certain cancers, heart disease, and age-related macular degeneration: a review of recent research.

Key epidemiologic studies show associations between high dietary intakes of certain carotenoid-containing fruits and vegetables and reduced risk of prostate cancer, breast cancer, head and neck cancers, cardiovascular disease, and age-related macular degeneration, although overall the evidence is inconsistent. Little is known about the potential biochemical mechanisms whereby carotenoids might protect against disease, and human intervention trials are limited to high dose beta-carotene, which is not protective against lung cancer or cardiovascular disease. Authoritative scientific organizations continue to emphasize increased consumption of fruits and vegetables but do not make specific recommendations for carotenoids because of a lack of data that directly link them to disease reduction.