At what age do normal weight Canadian children become overweight adults? Differences according to sex and metric.

BACKGROUND: The prevalence of overweight and obesity doubles between adolescence and young adulthood; however, the exact age, and appropriate metric to use to identify when overweight develops is still debated. AIM: To examine the age of onset of overweight by sex and four metrics: body mass index (BMI), fat mass (%FM), waist circumference (WC) and waist-to-height ratio (WHtR). SUBJECTS AND METHODS: Between 1991 and 2017, serial measures of body composition were taken on 237 (108 males) individuals (aged 8-40 years of age). Hierarchical random effects models were used to develop growth curves. Curves were compared to BMI, %FM and WC overweight age- and sex-specific cut-points. RESULTS: In males, the BMI growth curve crossed the cut-point at 22.0 years, compared to 23.5 and 26.5 years for WHtR and %FM, respectively; WC cut-off was not reached until 36 years. In females, the BMI growth curve crossed the overweight cut-point at 21.5 years, compared to 14.2 years for %FM and 21.9 and 27.5 years for WC and WHtR, respectively. CONCLUSION: In summary, overweight onset occurs during young adulthood with the exception of WC in males. BMI in males and %FM in females were the metrics identifying overweight the earliest.

Infection of the chalcid parasitoid Pteromalus venustus Walker (Hymenoptera: Pteromalidae) with the male-killing symbiont Arsenophonus nasoniae (Gamma-Proteobacteria: Enterobacteriaceae).

The male-killing symbiont Arsenophonus nasoniae is a gamma-proteobacterium that infects parasitic wasps; the male progeny of infected females exhibit increased embryonic death. In this study, we examined methods to horizontally infect Pteromalus venustus (a parasitoid infesting populations of the alfalfa leafcutting bee Megachile rotundata) with A. nasoniae. We then tested the success of these methods via semi-quantitative PCR and quantitative digital PCR, using a molecular marker specific to A. nasoniae. Controlled parasitoid mating experiments were then undertaken to determine whether infections of A. nasoniae in P. venustus induce the male-killing phenotype as has been reported for other host species; evidence of this male-killing phenotype was observed in the current study. Over the course of the eight parasitoid generations following introduction of A. nasoniae infection in P. venustus, the male component of the parasitoid sex ratio was substantially reduced in the infected population (1.05 ♂: 1.00 ♀) compared to the control population (2.46 ♂: 1.00 ♀). Establishment of stable A. nasoniae infections in P. venustus populations could lower the proportion of male progeny, thus negatively impacting the mating success of females, and reducing overall populations of the parasitoid in alfalfa leafcutting bee populations.

Upper and lower limb loading during weight-bearing activity in children: reaction forces and influence of body weight.

Weight bearing (WB) activity is important for healthy skeletal development. The magnitude of loading during WB activities, especially upper limb impacts, has yet to be quantified in children. This study quantifies ground reaction forces (GRF) experienced by children performing WB activities and examines the contribution of body weight (BW) to GRF. Fifty children, aged 8-12 were recruited (34 males). GRF were measured using force plates during 20 upper and lower limb activities (such as landing on the feet and hands). Sex differences in GRF and associations between peak force and BW were examined using independent sample t-tests and linear regressions (p < 0.05), respectively. Lower limb GRF varied from 2-6x BW with no significant sex differences. GRF during upper limb activities varied from 1/3-1.7x BW with males experiencing significantly greater GRF for 25% of activities. BW was significantly associated with peak force in almost all activities; however, GRF variation explained by BW was wide-ranging across activities and not dependent on limb or activity type (static vs dynamic). Therefore, factors other than BW, such as technique, may be important in determining forces experienced by children performing WB activity and should be considered when choosing activities for WB activity interventions.

Muscle and Myotendinous Tissue Properties at the Distal Tibia as Assessed by High-Resolution Peripheral Quantitative Computed Tomography.

High-resolution peripheral quantitative computed tomography (HR-pQCT) quantifies bone microstructure and density at the distal tibia where there is also a sizable amount of myotendinous (muscle and tendon) tissue (MT); however, there is no method for the quantification of MT. This study aimed (1) to assess the feasibility of using HR-pQCT distal tibia scans to estimate MT properties using a custom algorithm, and (2) to determine the relationship between MT properties at the distal tibia and mid-leg muscle density (MD) obtained from pQCT. Postmenopausal women from the Hamilton cohort of the Canadian Multicenter Osteoporosis Study had a single-slice (2.3 ± 0.5 mm) 66% site pQCT scan measuring muscle cross-sectional area (MCSA) and MD. A standard HR-pQCT scan was acquired at the distal tibia. HR-pQCT-derived MT cross-sectional area (MTCSA) and MT density (MTD) were calculated using a custom algorithm in which thresholds (34.22-194.32 mg HA/cm3) identified muscle seed volumes and were iteratively expanded. Pearson and Bland-Altman plots were used to assess correlations and systematic differences between pQCT- and HR-pQCT-derived muscle properties. Among 45 women (mean age: 74.6 ± 8.5 years, body mass index: 25.9 ± 4.3 kg/m2), MTD was moderately correlated with mid-leg MD across the 2 modalities (r = 0.69-0.70, p < 0.01). Bland-Altman analyses revealed no evidence of directional bias for MTD-MD. HR-pQCT and pQCT measures of MTCSA and MCSA were moderately correlated (r = 0.44, p < 0.01). Bland-Altman plots for MTCSA revealed that larger MCSAs related to larger discrepancy between the distal and the mid-leg locations. This is the first study to assess the ability of HR-pQCT to measure MT size, density, and morphometry. HR-pQCT-derived MTD was moderately correlated with mid-leg MD from pQCT. This relationship suggests that distal MT may share common properties with muscle throughout the length of the leg. Future studies will assess the value of HR-pQCT-derived MT properties in the context of falls, mobility, and balance.

Muscle analysis using pQCT, DXA and MRI.

Skeletal muscle is one of the larger organs of the body and is integrally involved in metabolic processes in both health and disease. The ability to accurately and precisely measure skeletal muscle structure is essential for understanding the changes that occur naturally over the lifespan as well as those observed in chronic disease, and in response to targeted interventions. Musculoskeletal imaging allows for the quantification of skeletal muscle mass and select modalities are also able to determine muscle quality. The purpose of this paper is to review peripheral quantitative computed tomography (pQCT), dual X-ray energy absorptiometry (DXA) and magnetic resonance imaging (MRI) techniques used to assess skeletal muscle size and quality in-vivo. Each modality is briefly described and the strengths and limitations are provided. No single imaging technique will be able to best address every clinical and research question of interest. Selecting the most appropriate imaging device for measuring skeletal muscle depends on access to technology, availability of expertise required for image acquisition and analysis, characteristics of the population, anatomical site of interest, and the level of structural detail required.

A longitudinal study of bone area, content, density, and strength development at the radius and tibia in children 4-12 years of age exposed to recreational gymnastics.

UNLABELLED: This study investigated the long-term relationship between the exposure to childhood recreational gymnastics and bone measures and bone strength parameters at the radius and tibia. It was observed that individuals exposed to recreational gymnastics had significantly greater total bone content and area at the distal radius. No differences were observed at the tibia. INTRODUCTION: This study investigated the relationship between exposure to early childhood recreational gymnastics with bone measures and bone strength development at the radius and tibia. METHODS: One hundred twenty seven children (59 male, 68 female) involved in either recreational gymnastics (gymnasts) or other recreational sports (non-gymnasts) between 4 and 6 years of age were recruited. Peripheral quantitative computed tomography (pQCT) scans of their distal and shaft sites of the forearm and leg were obtained over 3 years, covering the ages of 4-12 years at study completion. Multilevel random effects models were constructed to assess differences in the development of bone measures and bone strength measures between those exposed and not exposed to gymnastics while controlling for age, limb length, weight, physical activity, muscle area, sex, and hours of training. RESULTS: Once age, limb length, weight, muscle area, physical activity, sex, and hours of training effects were controlled, it was observed that individuals exposed to recreational gymnastics had significantly greater total bone area (18.0 ± 7.5 mm(2)) and total bone content (6.0 ± 3.0 mg/mm) at the distal radius (p < 0.05). This represents an 8-21 % benefit in ToA and 8-15 % benefit to ToC from 4 to 12 years of age. Exposure to recreational gymnastics had no significant effect on bone measures at the radius shaft or at the tibia (p > 0.05). CONCLUSIONS: Exposure to early life recreational gymnastics provides skeletal benefits to distal radius bone content and area. Thus, childhood recreational gymnastics exposure may be advantageous to bone development at the wrist.

Characterization of Melanoplus sanguinipes oviposition stimulating protein expression and re-examination of its potential role in stimulating oviposition.

Melanoplussanguinipes oviposition stimulating protein (MsOSP) was characterized and its role in stimulating oviposition in virgin females was examined. A 967nt MsOSP mRNA sequence with homology to previously characterized N-terminal amino acid sequence data for MsOSP was identified in a RNAseq library generated from an mRNA pool from the long hyaline tubule (LHT) of the male accessory gland complex. This transcript contained a predicted 729nt open reading frame encoding the 242aa putative MsOSP protein and had the second highest read abundance in the library. The MsOSP transcript was detected exclusively in the LHT tissue of adult males and its abundance increased with time until 7 days post-eclosion. Western blot analysis using an anti-MsOSP antibody showed high levels of MsOSP protein in the LHT luminal secretions of virgin males and to a lesser degree was associated with the aedeagus and ejaculatory duct. MsOSP was shown to be a major protein component of the spermatophore packet transferred from the male to female during copulation. However, only minor amounts of MsOSP could be detected in the female bursa, spermatheca and oviduct. Intrahemocoelic injection of LHT luminal protein into mature virgin females stimulated oviposition in ∼ 65% of females. A similar but non-significant trend was observed upon injection of purified recombinant MsOSP protein, and immunoprecipitation of LHT protein with anti-MsOSP antibody led to abrogation of oviposition stimulation upon injection of mature virgin females. Despite the demonstration of stimulation of oviposition upon intrahemocoelic injection of LHT-derived-MsOSP into mature virgin females, the potential mode of action of MsOSP in this process remains to be determined. MsOSP cannot be detected in the tissues other than the bursa, spermatheca and oviduct of female grasshoppers and relatively large quantities of MsOSP are required to stimulate oviposition upon injection.

Precompetitive and recreational gymnasts have greater bone density, mass, and estimated strength at the distal radius in young childhood.

UNLABELLED: Young recreational and precompetitive gymnasts had, on average, 23% greater bone strength at the wrist compared to children participating in other recreational sports. Recreational gymnastics involves learning basic movement patterns and general skill development and as such can easily be implemented into school physical education programs potentially impacting skeletal health. INTRODUCTION: Competitive gymnasts have greater bone mass, density, and estimated strength. The purpose of this study was to investigate whether the differences reported in the skeleton of competitive gymnasts are also apparent in young recreational and precompetitive gymnasts. METHODS: One hundred twenty children (29 gymnasts, 46 ex-gymnasts, and 45 non-gymnasts) between 4 and 9 years of age (mean = 6.8 ± 1.3) were measured. Bone mass, density, structure, and estimated strength were determined using peripheral quantitative computed tomography at the distal (4%) and shaft (65%, 66%) sites in the radius and tibia. Total body, hip, and spine bone mineral content (BMC) was assessed using dual energy X-ray absorptiometry. Analysis of covariance (covariates of sex, age and height) was used to investigate differences in total bone content (ToC), total bone density (ToD), total bone area (ToA), and estimated strength (BSI) at the distal sites and ToA, cortical content (CoC), cortical density (CoD), cortical area (CoA), cortical thickness, medullary area, and estimated strength (SSIp) at the shaft sites. RESULTS: Gymnasts and ex-gymnasts had 5% greater adjusted total body BMC and 6-25% greater adjusted ToC, ToD, and BSI at the distal radius compared to non-gymnasts (p < 0.05). Ex-gymnasts had 7-11% greater CoC and CoA at the radial shaft and 5-8% greater CoC and SSIp at the tibial shaft than gymnasts and non-gymnasts. Ex-gymnasts also had 12-22% greater ToC and BSI at the distal tibia compared to non-gymnasts (p < 0.05). CONCLUSION: This data suggests that recreational and precompetitive gymnastics participation is associated with greater bone strength.

Insect intestinal mucins and serine proteases associated with the peritrophic matrix from feeding, starved and moulting Mamestra configurata larvae.

Insect intestinal mucins (McIIM2-4) expressed in the midgut of feeding, starved and moulting Mamestra configurata larvae were identified. McIIM2 and McIIM4 were associated with the peritrophic matrix (PM). PMs from feeding and starved larvae were translucent and contained organized chitin bundles perpendicular to their long axis, whereas PM from moulting larvae consisted of an inner opaque mass surrounded by an outer translucent sleeve. Serine protease genes (McSP1, McSP2, McSP25 and McSP29) were also expressed in these larvae and several serine proteases were associated with the PM. Serine protease activity was also detected in the midgut of feeding, starved and moulting larvae.

A chitin deacetylase and putative insect intestinal lipases are components of the Mamestra configurata (Lepidoptera: Noctuidae) peritrophic matrix.

One- and two-dimensional gel electrophoresis coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to identify cDNA encoding a chitin deacetylase (McCDA1) and three insect intestinal lipases (McIIL1, McIIL2 and McIIL3) associated with the Mamestra configurata (bertha armyworm) peritrophic matrix. Recombinant McCDA1 was active and chitin deacetylase activities were detected in the midgut. McCDA1 and the McIIL genes were expressed exclusively in the midgut; however, McCDA1 and McIIL2 were expressed in all larval stages, whereas McIIL1 was expressed mainly in feeding larvae and McIIL3 primarily during the moult.

Does host plant influence parasitism and parasitoid species composition in Lygus rugulipennis? A molecular approach.

Lygus Hahn plant bugs (Hemiptera: Miridae) are serious pests of a wide variety of economically important crops in North America. European Peristenus digoneutis Loan and P. relictus Ruthe (Hymenoptera: Braconidae) are being considered for release in Canada as part of a classical biological control program for Lygus. The attractiveness of different host plants to European Peristenus has not been addressed, but may be an important consideration prior to parasitoid release. Lygus rugulipennis Poppius nymphs were collected in the Northern Temperate Atlantic (NTA) ecoregion on red clover (Trifolium pratense L.; Fabaceae) and chamomile (Matricaria recutita L.; Asteraceae), and in the Western European Broadleaf Forest (WEBF) ecoregion on red clover and alfalfa (Medicago sativa L.; Fabaceae). Parasitism levels and parasitoid species were determined using a multiplex PCR assay for P. digoneutis, P. relictus, and P. pallipes Curtis. Mean parasitism levels in L. rugulipennis were 45-49% in the NTA ecoregion and 25-32% in the WEBF ecoregion. However, in neither ecoregion were parasitism levels and parasitoid species compositions significantly different in nymphs from different host plant species. Furthermore, multiparasitism was low despite the fact that P. digoneutis and P. relictus share the same host species.

Changes in cysteine protease activity and localization during midgut metamorphosis in the crucifer root maggot (Delia radicum).

We show that differential localization and/or activation of two cysteine protease activities occur at the onset of dipteran midgut metamorphosis. A 26 kDa cysteine protease activity was associated specifically with midgut tissues of late third instar larvae. Starvation of mid third instar larvae simulated the onset of prepupation and resulted in loss of the 26 kDa protease activity. A cDNA clone encoding a cysteine protease, termed DrCP1, was isolated and shown to be highly similar to those from Sarcophaga peregrina and Drosophila melanogaster (DmCP1). DrCP1 mRNA was present in all developmental stages including eggs, larvae, pupae and adults, but was highly induced at the onset of the larval-pupal transition and thereafter. The DrCP1 protein is localized to the exterior of the midgut tissues during the onset of the prepupal transition period, possibly in response to ecdysone. Analysis of transcription factor binding sites associated with the DmCP1 promoter indicated that elements exist that allow for both ecdysone-mediated as well as tissue-specific regulation. Based upon these and other studies we propose: (1) that the expression, activity and localization of the DrCP1-like cysteine proteases are highly regulated throughout development; and, (2) that cysteine protease activities are involved in aspects of tissue reconstruction at the onset of and during metamorphosis.

A holistic approach for determining the entomopathogenic potential of Bacillus thuringiensis strains.

The cry gene content of Bacillus thuringiensis subsp. aizawai HD-133 was analyzed by a combination of high-pressure liquid chromatography (HPLC) and exclusive PCR. A total of six cry genes were detected in genomic DNA purified from HD-133, four from the cry1 family (cry1Aa, cry1Ab, cry1C, and cry1D) as well as a gene each from the cry2 (cry2B) and the cry1I families. To directly determine which genes were expressed and crystallized in the purified parasporal inclusions, solubilized and trypsinized HD-133 crystals were subjected to chromatographic separation by HPLC. Only three proteins, Cry1Ab, Cry1C, and Cry1D, were found, in a 60/37/3 ratio. Dot blot analysis of total mRNA purified from HD-133 showed that both the cry2B and cry1I genes, but not the cry1Aa gene, were transcribed. Cloning and sequencing of the cry1Aa gene revealed an inserted DNA sequence within the cry coding sequence, resulting in a disrupted reading frame. Taken together, our results show that combining crystal protein analysis with a genetic approach is a highly complementary and powerful way to assess the potential of B. thuringiensis isolates for new insecticidal genes and specificities. Furthermore, based on the number of cryptic genes found in HD-133, the total cry gene content of B. thuringiensis strains may be higher than previously thought.

A physical map of the Mamestra configurata nucleopolyhedrovirus genome and sequence analysis of the polyhedrin gene.

The genome structure of a nucleopolyhedrovirus (NPV) isolated from the bertha armyworm, Mamestra configurata Walker (Lepidoptera: Noctuidae) (MacoNPV) was analysed with six restriction endonucleases (REN): BamHI, EcoRI, HindIII, PstI, SmaI and Xhol. More than 70 MacoNPV REN fragments were cloned into plasmids pUC18 and pBluescript SK(+). The physical map with 112 restriction sites for the above REN was constructed using double digests and Southern blot hybridization analysis of the MacoNPV DNA clones. The size of the DNA genome of the MacoNPV-90/2 isolate used for this study was estimated at 156 kbp based on REN fragment sizes. The position of the polyhedrin gene, which has by convention been used as the zero point of the REN maps of NPV, was determined by hybridizing the Autographa californica multicapsid nucleopolyhedrovirus HindIII-V fragment clone, which contains most of the polyhedrin gene, with genomic blots of MacoNPV. The cloned MacoNPV fragments identified as containing the polyhedrin gene were sequenced and an ORF coding for a 246 amino acid polypeptide with 98.7% sequence identity with Panolis flammea nucleopolyhedrovirus (PaflNPV) polyhedrin protein was identified. The putative polyhedrin gene sequence had 97.2% and 91.2% identity with the PaflNPV and Mamestra brassicae multicapsid nucleopolyhedrovirus polyhedrin gene sequences, respectively, and also contained an upstream region identical to the highly conserved 12 bp consensus sequence TGTAAGT-AATTT typical of NPV very late genes.

Cricothyrotomy in the emergency department revisited.

Thirty-nine emergency cricothyrotomies were reviewed from the emergency department of Hennepin County Medical Center during the 4-year period ending December 1985. Due to technical changes in airway management and a desire to assess their impact, this experience was compared with a previously reported series of 38 emergency cricothyrotomies from the same department. Technical changes include the use of paralyzing agents, transtracheal needle ventilation, and the use of only vertical skin incisions and #4 Shiley tubes when cricothyrotomy is performed. The presenting problem, indications for cricothyrotomy and complications of the procedure were compared between the two series. Fewer cricothyrotomies were done as a fraction of total surgical and nonsurgical tracheal intubations in the present series (1.7%) compared to the previous series (2.7%). The complication rate decreased from 40% in the previous series to 23% in the present series. Incorrect site of tube placement (10%) and hemorrhage (8%) remain the two leading complications. However, the tube was in the trachea in all cases, and acceptable ventilation was achieved. No patient developed a clinically significant hematoma or hemorrhage from cricothyrotomy. It is concluded that our technical changes in airway management have helped to decrease both the relative frequency of cricothyrotomy and the complication rate.

Iopamidol arteriography: discomfort and pain.

A double-blind, randomized study was performed to compare discomfort and pain associated with the use of iopamidol and Hypaque (diatrizoate sodium and diatrizoate meglumine) during iliofemoral runoff arteriography in 33 patients. Iopamidol caused substantially less discomfort and pain. The evaluation was helped by audiotaping the study and comparing patients' vocal responses to injections of these materials.

Size and map locations of early transcription products on the Autographa californica nuclear polyhedrosis virus genome.

The size classes and map locations of early transcripts of Autographa californica nuclear polyhedrosis virus were identified by probing Northern blots with cloned viral DNA fragments. Twelve abundant and 30 minor transcripts were detected by 4 hr postinfection. There was an increase in the abundancy and number of virus-specific transcripts between 6 and 8 hr postinfection, coincident with the onset of DNA replication. The change in transcription pattern did not occur in cells infected at the nonpermissive temperature with a DNA-negative mutant indicating that these early transcripts were synthesized prior to the initiation of viral DNA replication. Two early transcripts, 4.6 and 1.1 kb, mapped to the genomic region of the temperature-sensitive lesion, between 60.1 and 62.0%.

Mapping early transcription products of Autographa californica nuclear polyhedrosis virus.

The regions of the AcMNPV genome represented as cytoplasmic transcripts early after infection of Spodoptera frugiperda cells prior to and encompassing the initiation of DNA replication were mapped. In vivo(32)P pulse-labeled cytoplasmic RNA from infected cells at various times postinfection was used to probe Southern blots of cloned EcoRI AcMNPV DNA fragments. At the earliest time point studied (0.5 - 2.5 hr p.i.) transcripts represented a large proportion of the genome although specific regions were predominantly transcribed (EcoRI A, C, F, J, O, Q, S, and T). After the onset of viral DNA synthesis predominant cytoplasmic transcripts represented more dispersed areas of the genome, particularly those regions which were only weakly transcribed earlier after infection. Genomic regions containing major late genes were not predominantly transcribed by 7.5 hr p.i.