Application of an in silico approach identifies a genetic locus within ITGB2, and its interactions with HSPG2 and FGF9, to be associated with anterior cruciate ligament rupture risk

We developed a Biomedical Knowledge Graph model that is phenotype and biological function-aware through integrating knowledge from multiple domains in a Neo4j, graph database. All known human genes were assessed through the model to identify potential new risk genes for anterior cruciate ligament (ACL) ruptures and Achilles tendinopathy (AT). Genes were prioritised and explored in a case-control study comparing participants with ACL ruptures (ACL-R), including a sub-group with non-contact mechanism injuries (ACL-NON), to uninjured control individuals (CON). After gene filtering, 3376 genes, including 411 genes identified through previous whole exome sequencing, were found to be potentially linked to AT and ACL ruptures. Four variants were prioritised: HSPG2:rs2291826A/G, HSPG2:rs2291827G/A, ITGB2:rs2230528C/T and FGF9:rs2274296C/T. The rs2230528 CC genotype was over-represented in the CON group compared to ACL-R (p < 0.001) and ACL-NON (p < 0.001) and the TT genotype and T allele were over-represented in the ACL-R group and ACL-NON compared to CON (p < 0.001) group. Several significant differences in distributions were noted for the gene-gene interactions: (HSPG2:rs2291826, rs2291827 and ITGB2:rs2230528) and (ITGB2:rs2230528 and FGF9:rs2297429). This study substantiates the efficiency of using a prior knowledge-driven in silico approach to identify candidate genes linked to tendon and ACL injuries. Our biomedical knowledge graph identified and, with further testing, highlighted novel associations of the ITGB2 gene which has not been explored in a genetic case control association study, with ACL rupture risk. We thus recommend a multistep approach including bioinformatics in conjunction with next generation sequencing technology to improve the discovery potential of genomics technologies in musculoskeletal soft tissue injuries.HighlightsA biomedical knowledge graph was modelled for musculoskeletal soft tissue injuries to efficiently identify candidate genes for genetic susceptibility analyses.The biomedical knowledge graph and sequencing data identified potential biologically relevant variants to explore susceptibility to common tendon and ligament injuries. Specifically genetic variants within the ITGB2 and FGF9 genes were associated with ACL risk.Novel allele combinations (HSPG2-ITGB2 and ITGB2-FGF9) showcase the potential effect of ITGB2 in influencing risk of ACL rupture.

Exploring Flood Response Challenges, Training Needs, and the Impact of Online Flood Training for Lifeguards and Water Safety Professionals in South Africa

Flooding is a significant cause of human and economic loss in the African region, including in South Africa. Flood mitigation and response in South Africa is challenging due to a range of environmental, infrastructure, and policy constraints. Lifeguards represent a potential additional workforce to bolster flood mitigation and response. This study aimed to explore the feasibility and acceptability of online flood safety training for water safety professionals in South Africa, as well as assess the current flood response capacity and future needs of this group. Online surveys were completed by a convenience sample of South African water safety professionals (including lifeguards) pre-and post a series of four online flood training workshops. Free text responses were thematically coded and flood knowledge was compared between the pre-and post-workshop survey respondents. Sixty-eight responses were analysed (64.7% pre-workshop phase; 63.2% male, 29.4% aged 50-59 years). A range of challenges in flood mitigation and response were identified including equipment, training, and a lack of government support. However, positives were also identified including respondents' willingness to assist in flood emergencies and good cooperation with neighbouring countries and across the region. Opportunities for better cross-municipal and government communication were discussed. In times of crisis, or in resource poor settings, water safety professionals can bolster traditional flood mitigation and response capacity. Opportunities exist to harness this willingness, but also improve cross-governmental and municipal knowledge sharing to improve future flood mitigation and response efforts in South Africa.

Factors which affect the application and implementation of a spinal motion restriction protocol by prehospital providers in a low resource setting: A scoping review

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There is a need for a patient-centred approach to the prehospital spinal management approach, which considers the associated risks, available personnel and limited resources.

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There is limited evidence supporting the use of the NEXUS and CCR decision tools in the prehospital setting.

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Prehospital spinal motion restriction decision tools should focus on reducing unnecessary spinal motion restriction and its associated adverse effects

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Developing a decision tool with more context-specific prehospital instructions for selective spinal motion restriction is of value.

Introduction

The safety and effectiveness of prehospital clinical c-spine clearance or spinal motion restriction (SMR) decision support tools are unclear. The present study aimed to examine the available literature on clinical cervical spine clearance and selective SMR decision support tools to identify possible barriers to implementation, safety, and effectiveness when used by emergency medical service (EMS) practitioners.

Method

We performed a focused scoping review of published literature on the prehospital use of clinical c-spine clearance and SMR decision tools in adult blunt trauma patients. The Medline, Embase, Cochrane Library, Cumulative Index of Nursing and Allied Health Literature, Web of Science, Turning Research into Practice and EBSCOhost online databases were searched (February 2021). The type of decision support tool and facilitators and barriers to its use were extracted from each included publication in accordance with a modified descriptive-analytical framework. Extracted data were subjected to thematic analysis.

Results

Following screening, forty-two articles were included in this scoping review. No studies conducted specifically in low resource settings were found. The majority of articles (57%) evaluated the use of specific SMR decision support tools, such as the National Emergency X-Radiography Utilization Study (NEXUS) and the Canadian C-spine Rule (CCR). Potential facilitators of safe and effective use were identified in 60%, and potential barriers to safe and effective use in 55% of included articles. Only one study evaluated the CCR when used by EMS practitioners, making it difficult to determine its appropriateness for implementation in the prehospital setting.

Conclusion

This is the first scoping review, to our knowledge, that has attempted to identify the possible barriers and facilitators to their implementation, safety, and effectiveness when used by EMS practitioners. Key issues identified included terminology, guideline compliance and implementation, and a lack of context-specific evidence. These may provide important considerations for future guideline development.

Exploring new genetic variants within COL5A1 intron 4-exon 5 region and TGF-β family with risk of anterior cruciate ligament ruptures

Variants within genes encoding structural and regulatory elements of ligaments have been associated with musculoskeletal soft tissue injury risk. The role of intron 4-exon 5 variants within the α1 chain of type V collagen (COL5A1) gene and genes of the transforming growth factor-β (TGF-β) family, TGFBR3 and TGFBI, was investigated on the risk of anterior cruciate ligament (ACL) ruptures. A case-control genetic association study was performed on 210 control (CON) and 249 participants with surgically diagnosed ruptures (ACL), of which 147 reported a noncontact mechanism of injury (NON). Whole-exome sequencing data were used to prioritize variants of potential functional relevance. Genotyping for COL5A1 (rs3922912 G>A, rs4841926 C>T, and rs3124299 C>T), TGFBR3 (rs1805113 G>A and rs1805117 T>C), and TGFBI (rs1442 G>C) was performed using Taqman SNP genotyping assays. Significant overrepresentation of the G allele of TGFBR3 rs1805113 was observed in CON vs ACL (P = .014) and NON groups (P = .021). Similar results were obtained in a female with the G allele (CON vs ACL: P = .029; CON vs NON: P = .016). The TGFBI rs1442 CC genotype was overrepresented in the female ACL vs CON (P = .013). Associations of inferred allele combinations were observed in line with the above results. COL5A1 intron 4-exon 5 genomic interval was not associated with the risk of ACL ruptures. Instead, this novel study is the first to use this approach to identify variants within the TGF-β signaling pathway to be implicated in the risk of ACL ruptures. A genetic susceptibility interval was identified to be explored in the context of extracellular matrix remodeling.

Defining the molecular signatures of Achilles tendinopathy and anterior cruciate ligament ruptures: A whole-exome sequencing approach

Musculoskeletal soft tissue injuries are complex phenotypes with genetics being one of many proposed risk factors. Case-control association studies using the candidate gene approach have predominately been used to identify risk loci for these injuries. However, the ability to identify all risk conferring variants using this approach alone is unlikely. Therefore, this study aimed to further define the genetic profile of these injuries using an integrated omics approach involving whole exome sequencing and a customised analyses pipeline. The exomes of ten exemplar asymptomatic controls and ten exemplar cases with Achilles tendinopathy were individually sequenced using a platform that included the coverage of the untranslated regions and miRBase miRNA genes. Approximately 200 000 variants were identified in the sequenced samples. Previous research was used to guide a targeted analysis of the genes encoding the tenascin-C (TNC) glycoprotein and the α1 chain of type XXVII collagen (COL27A1) located on chromosome 9. Selection of variants within these genes were; however, not predetermined but based on a tiered filtering strategy. Four variants in TNC (rs1061494, rs1138545, rs2104772 and rs1061495) and three variants in the upstream COL27A1 gene (rs2567706, rs2241671 and rs2567705) were genotyped in larger Achilles tendinopathy and anterior cruciate ligament (ACL) rupture sample groups. The CC genotype of TNC rs1061494 (C/T) was associated with the risk of Achilles tendinopathy (p = 0.018, OR: 2.5 95% CI: 1.2-5.1). Furthermore, the AA genotype of the TNC rs2104772 (A/T) variant was significantly associated with ACL ruptures in the female subgroup (p = 0.035, OR: 2.3 95% CI: 1.1-5.5). An inferred haplotype in the TNC gene was also associated with the risk of Achilles tendinopathy. These results provide a proof of concept for the use of a customised pipeline for the exploration of a larger genomic dataset. This approach, using previous research to guide a targeted analysis of the data has generated new genetic signatures in the biology of musculoskeletal soft tissue injuries.

Incidental diagnosis of tuberous sclerosis complex by exome sequencing in three families with subclinical findings

Tuberous sclerosis complex (TSC) is an autosomal-dominant neurocutaneous disorder characterized by lesions and benign tumors in multiple organ systems including the brain, skin, heart, eyes, kidneys, and lungs. The phenotype is highly variable, although penetrance is reportedly complete. We report the molecular diagnosis of TSC in individuals exhibiting extreme intra-familial variability, including the incidental diagnosis of asymptomatic family members. Exome sequencing was performed in three families, with probands referred for epilepsy, autism, and absent speech (Family 1); epileptic spasms (Family 2); and connective tissue disorders (Family 3.) Pathogenic variants in TSC1 or TSC2 were identified in nine individuals, including relatives with limited or no medical concerns at the time of testing. Of the nine individuals reported here, six had post-diagnosis examinations and three met clinical diagnostic criteria for TSC. One did not meet clinical criteria for a possible or definite diagnosis of TSC, and two had only a possible clinical diagnosis following post-diagnosis workup. These individuals as well as their mothers demonstrated limited features that would not raise concern for TSC in the absence of molecular results. In addition, three individuals exhibited epilepsy with normal brain MRIs, and two without seizures or intellectual disability had MRI findings fulfilling major criteria for TSC highlighting the difficulty providers face when relying on clinical criteria to guide genetic testing. Given the importance of a timely TSC diagnosis for clinical management, such cases demonstrate a potential benefit for clinical criteria to include seizures and an unbiased molecular approach to genetic testing.

The interaction of polymorphisms in extracellular matrix genes and underlying miRNA motifs that modulate susceptibility to anterior cruciate ligament rupture

OBJECTIVES

Variants within genes that encode proteins regulating fibrillogenesis such as BGN (rs1126499 C>T, rs1042103 C>T), COL5A1 (rs12722 C>T) and DCN (rs516115 C>T) have been associated with susceptibility to anterior cruciate ligament (ACL) ruptures. A miRNA mediated transcript instability was proposed for the COL5A1 association. The study aims were: (i) to investigate the association of inferred allele combinations across the COL5A1 3'-UTR, BGN and DCN genes with susceptibility to ACL rupture; and (ii) to use an in silico approach to identify miRNA binding sites common to these risk associated allele combinations.

DESIGN

Case-control association study METHODS: Allele combinations were generated from the genotype data of the BGN (rs1126499, rs1042103), COL5A1 (rs12722) and DCN (rs516115) loci for 227 participants with surgically diagnosed ACL ruptures and 234 asymptomatic controls. Statistical analyses between the CON and ACL groups as well as sex-specific interactions were investigated. Significance was accepted at p<0.05. miRNA binding sites within these genes were identified using DIANA tools.

RESULTS

Several sex-specific inferred allele combinations were associated with altered susceptibility and miRNA (miR-22, miR-27b, miR-140, miR-199a, miR-199b, miR-299, miR-338 and miR-484) recognition motifs were identified in range of these susceptibility loci.

CONCLUSIONS

In conclusion, this study has implicated inferred allele combinations across BGN (rs1126499, rs1042103), COL5A1 (rs12722) and DCN (rs516115) as well as eight miRNA recognition sequences in susceptibility to ACL rupture. The biological significance of these genomic signatures needs to be explored to understand their effect on the ligaments functional capacity.

Extracellular matrix proteins interact with cell-signaling pathways in modifying risk of achilles tendinopathy

The aim of this study was to investigate interactions between variants within genes encoding components of the collagen fibril and components of cell-signaling pathways within the extracellular matrix, and determine the relative contribution of these variants to Achilles tendinopathy risk in a polygenic model. A total of 339 asymptomatic control participants and 179 participants clinically diagnosed with Achilles tendinopathy were genotyped for variants within six genes encoding components of the collagen fibril and three genes encoding components of cell-signaling pathways. Logistic regression, stepwise selection, and receiver operating characteristic curve (ROC) analysis was used to select and evaluate genetic interactions and determine the relative contribution of these variants to overall genetic risk. The strongest, best fit polygenic risk model included the variables sex, three COL27A1 variants (rs4143245; rs1249744; rs946053), COL5A1 rs12722, CASP8 rs1045485, and CASP8 rs2824129 with an area under the ROC curve of 0.737 and the maximum sum of sensitivity and specificity indicators equal to 134%. Significant interactions between genes encoding components of the collagen fibril and genes encoding components of the cell-signaling pathways modify risk of Achilles tendinopathy.

A variant within the AQP1 3'-untranslated region is associated with running performance, but not weight changes, during an Ironman Triathlon

The objective of this study was to test the association of the rs1049305 (G > C) variant within the 3'-untranslated region of the aquaporin 1 gene, AQP1, with changes in body weight, post-race serum sodium concentration and performance in Ironman triathletes. Five hundred and four male Ironman triathletes were genotyped for the rs1049305 variant within the AQP1 gene. Change in pre- and post-race body weight was calculated for 470 triathletes and used as a proxy for changes in body fluid during the race, as well as to divide triathletes into biologically relevant weight-loss groups (0-3%, 3-5% and >5%). There were no rs1049305 genotype effects on post-race serum sodium concentrations (P = 0.647), pre-race weight (P = 0.610) nor relative weight change during the Ironman Triathlons (P = 0.705). In addition, there were no significant differences in genotype (P = 0.640) nor allele (P = 0.643) distributions between the weight loss groups. However, triathletes who carry a C-allele were found to complete the 42.2-km run stage faster (mean 286, s = 49 min) than triathletes with a GG genotype (mean 296, s = 47 min; P = 0.032). The AQP1 rs1049305 variant is associated with running performance, but not relative body weight change, during the 2000, 2001 and 2006 South African Ironman Triathlons.

Investigation of variants within the COL27A1 and TNC genes and Achilles tendinopathy in two populations

The TNC gene has previously been associated with Achilles tendinopathy (AT) in a South African population. The aims of this study were (i) to investigate the association of single nucleotide polymorphisms within the TNC gene, and the additional candidate gene, COL27A1, with AT in two populations, and (ii) to identify if there is a risk haplotype for AT in both populations. Three hundred and thirty nine healthy control participants (CON) and 179 participants clinically diagnosed with AT (TEN) from South Africa and Australia, were genotyped for variants: rs4143245, rs1249744, rs753085, rs946053 (COL27A1) and rs13321, rs2104772, rs1330363 (TNC). Haplotypes were inferred using the genotype data. The rs2104772 (p = 0.017) and rs1330363 (p = 0.020) variants within TNC showed a significant allele association with AT. The GCA haplotype (rs946053-rs13321-rs2104772) occurred significantly more frequently in TEN participants compared to CON (27% vs. 18%; p = 0.019). This study further implicates the genomic region containing the TNC and COL27A1 genes in influencing risk of AT, and maps the potential risk allele to a genetic interval flanked by rs946053 and rs2104772. This region may have functional effects on the transcription, structure and properties of tenascin-C and the alpha-1 chain of type XXVII collagen.

Dissecting the role of TRPV1 in detecting multiple trigeminal irritants in three behavioral assays for sensory irritation

Polymodal neurons of the trigeminal nerve innervate the nasal cavity, nasopharynx, oral cavity and cornea. Trigeminal nociceptive fibers express a diverse collection of receptors and are stimulated by a wide variety of chemicals. However, the mechanism of stimulation is known only for relatively few of these compounds. Capsaicin, for example, activates transient receptor potential vanilloid 1 (TRPV1) channels. In the present study, wildtype (C57Bl/6J) and TRPV1 knockout mice were tested in three behavioral assays for irritation to determine if TRPV1 is necessary to detect trigeminal irritants in addition to capsaicin. In one assay mice were presented with a chemical via a cotton swab and their response scored on a 5 level scale. In another assay, a modified two bottle preference test, which avoids the confound of mixing irritants with the animal’s drinking water, was used to assess aversion. In the final assay, an air dilution olfactometer was used to administer volatile compounds to mice restrained in a double-chambered plethysmograph where respiratory reflexes were monitored. TRPV1 knockouts showed deficiencies in the detection of benzaldehyde, cyclohexanone and eugenol in at least one assay. However, cyclohexanone was the only substance tested that appears to act solely through TRPV1.

Flammable gas cloud build up in a ventilated enclosure

Ventilation is frequently used as a means for preventing the build up of flammable or toxic gases in enclosed spaces. The effectiveness of the ventilation often has to be considered as part of a safety case or risk assessment. In this paper methods for assessing ventilation effectiveness for hazardous area classification are examined. The analysis uses data produced from Computational Fluid Dynamics (CFD) simulations of low-pressure jet releases of flammable gas in a ventilated enclosure. The CFD model is validated against experimental measurements of gas releases in a ventilation-controlled test chamber. Good agreement is found between the model predictions and the experimental data. Analysis of the CFD results shows that the flammable gas cloud volume resulting from a leak is largely dependent on the mass release rate of flammable gas and the ventilation rate of the enclosure. The effectiveness of the ventilation for preventing the build up of flammable gas can therefore be assessed by considering the average gas concentration at the enclosure outlet(s). It is found that the ventilation rate of the enclosure provides a more useful measure of ventilation effectiveness than considering the enclosure air change rate.

Training volume and injury incidence in a professional rugby union team

Objective. To describe the incidence of injuries in a professional rugby team, and to identify any associations between injury rates and training volume.Methods. This retrospective, descriptive study included all injuries diagnosed as grade 1 and above in a South African Super 12 rugby team. Injury incidence and injury rates were calculated and compared with training volume and hours of match play.Results. Thirty-eight male rugby players were injured during the study period. The total number of annual injuries decreased from 50 (2002) to 38 (2004) (χ2=0.84, p=0.36). The number of new injuries showed a similar trend (χ2=2.81, p=0.09), while the number of recurring injuries increased over the 3-year period. There was a tendency for total in-season injury rates to decrease over the 3 years (χ2=2.89, p=0.09). The pre-season injury rate increased significantly over the 3 years (χ2=12.7, pConclusions. One has to be cognisant of the balance between performance improvement and injury risk when designing training programmes for elite rugby players. Although the reduction in training volume was associated with a slight reduction in the number of acute injuries and in-season injury rates over the three seasons, the performance of the team changed from 3rd to 7th (2002 and 2004, respectively). Further studies are required to determine the optimal training necessary to improve rugby performancewhile reducing injury rates.

No association of the ACTN3 gene R577X polymorphism with endurance performance in Ironman Triathlons

Alpha-actinins are major structural components of the Z-discs in skeletal muscle. Alpha-actinin 3 is encoded by the ACTN3 gene and is expressed only in type II muscle fibres. Homozygosity for the nonsense mutation, 577X, within ACTN3 results in deficiency of alpha-actinin-3 but does not result in an abnormal muscular phenotype. Previous research has found an association of the 577R allele with sprinting and/or power performance. It has also been suggested that the 577X allele may confer an advantage during endurance events. Four hundred and fifty seven Caucasian male triathletes who completed either the 2000 and/or 2001 226 km South African Ironman Triathlons, and 143 Caucasian controls, were genotyped for the R577X mutation within the ACTN3 gene. There were no significant differences in either the genotype (P = 0.486) or allele (P = 0.375) frequencies within the fastest, middle of the field or slowest Caucasian male finishers and the control population. In conclusion, the R577X polymorphism within the ACTN3 gene was not associated with ultra-endurance performance in the 2000 and 2001 South African Ironman Triathlons.

Characteristics of pesticide pyrotechnic smoke devices

Pesticide smoke generating products are widely used by amateurs and professionals but there is little published information available about their burn and deposition characteristics to enable the risks associated with using these devices to be assessed. This paper investigates their burn characteristics, deposition patterns, pesticide air concentrations and potential exposure to operators. Thirteen firings were carried out in different spaces with different ventilation conditions. Three types of devices were investigated: dicloran, permethrin and red dye. Pesticide air concentrations increased after firing, reaching a maximum determined by the room volume in approximately 10 min and decreasing exponentially as a result of ventilation and deposition. Ejected pesticide was present in the aerosol phase but there were only occasional traces of vapour. Settlement of pesticide was affected by surface orientation, height, sampling material and the pesticide-to-space volume ratio. The manufacturer's recommended treatment period for dicloran of 4 h followed by half an hour of ventilation may be insufficient to reduce pesticide to safe levels for re-entry under very calm conditions.

Dipsogenic genes associated with weight changes during Ironman Triathlons

Thirst is regulated by a complex interaction of signalling pathways within the central nervous system, including components of the renin-angiotensin and kalikrein kinin systems, as well as the serotonergic pathways. The aim of this study was to determine whether there were any associations between polymorphisms within the ACE, BDKRB2, NOS3 and/or 5-HTT genes with weight changes during the 2000 and 2001 226 km South African Ironman Triathlons. Pre- and post-race serum [Na(+)] and body weights, as well as genotype data, were collected from 428 (61.1%) Caucasian male triathletes who were divided into three groups according to their relative weight loss during the triathlon (0-3, 3-5 and >5%). There was a significant linear trend for the distribution of both the BDKRB2 +9/+9 genotype and the 5-HTT SS genotype between the three weight loss groups, with the >5% group having the highest percentage of athletes with the +9/+9 genotype (chi(2)=5.3, P=0.021) and the highest percentage of athletes with the SS genotype (chi(2)=5.8, P=0.016). Likewise, the >5% group had the highest percentage of athletes with the combined SS 5-HTT and/or +9/+9 BDKRB2 genotypes (chi(2)=7.4, P=0.007). In conclusion, the functional SS genotype of the serotonin transporter-linked polymorphic region (5-HTTLPR) within the 5-HTT gene and the functional +9/+9 genotype of the BDKBR2 gene were associated with larger weight losses during the Ironman Triathlons. These findings suggest the involvement of the serotonergic pathways in the control of thirst and drinking behaviour and provide further evidence for the dipsogenic effect of circulating bradykinin.

The bradykinin beta 2 receptor (BDKRB2) and endothelial nitric oxide synthase 3 (NOS3) genes and endurance performance during Ironman Triathlons

We have previously shown that the insertion allele of the angiotensin-converting enzyme (ACE) gene was over-represented in the fastest South-African-born finishers of the South African Ironman Triathlons. As ACE is a component of the skeletal muscle kallikrein-kinin system (KKS), the aim of this study is to determine if there are any further associations between polymorphisms within the BDKRB2 and NOS3 genes, which encode for the KKS components, bradykinin beta(2) receptor and nitric oxide synthase, respectively, and ultra-endurance performance during the Ironman Triathlons. Four-hundred and forty-three male Caucasian triathletes who completed the 2000 and/or 2001 South African Ironman Triathlons and 203 healthy Caucasian male control subjects were genotyped for the functional -9/+9 polymorphism within exon 1 of the BDKRB2 gene and the G894T NOS3 gene polymorphisms. The BDKRB2 -9/-9 genotype occurred at a significantly higher frequency when the triathlete group (27.0%) was compared with the control group (19.3%, P=0.035). When divided into tertiles, there was also a significant linear trend for the NOS3 GG genotype distribution among the fastest (35.0%), middle (40.4%) and slowest (46.9%) finishers (P=0.039). The overall finishing times of the triathletes with an NOS3 GG genotype together with a BDKRB2 +9 allele were significantly slower than those with other genotype combinations (P=0.001). The NOS3/BDKRB2 genotype (beta=-0.150, B=-31.48, P=0.002), together with body mass index and age, accounted for 14.6% of the variance in the overall race time for the triathlon. In conclusion, both the NOS3 and BDKRB2 genes are associated with the actual performance during the Ironman Triathlons.

Functional analysis of the human galactose-1-phosphate uridyltransferase promoter in Duarte and LA variant galactosemia

Human galactose-1-phosphate uridyltransferase (hGALT) is an evolutionarily conserved enzyme central to D-galactose metabolism. The impairment of hGALT causes galactosemia. One missense mutation, an aspartate to asparagine substitution at amino acid 314 (N314D), impairs 50% activity in the homozygous state in some patients but gives near normal activity in others. The former condition is called Duarte (D) and the latter, Los Angeles (LA). The D allele is linked to hGALT polymorphisms including a deletion 5'to the translation start site (-119 to -116delGTCA), g1391G --> A and g1105G --> C. The LA allele is linked to a g1721C --> T transition. To investigate possible mechanisms for differences in hGALT activity between the D and LA alleles, we sequenced 3951 nucleotides of genomic DNA 5' to the hGALT translation start site. Using a dual-luciferase reporter system to express deletion constructs of the hGALT promoter, we noted both positive and negative regulatory regions. Two putative positive regulatory domains overlap with the naturally occurring -119 to -116delGTCA linked to Duarte. One is an E-box motif (CACGTG) at -117 to -112 bp. The second is an AP-1 motif (TCAGTCAG) at -124 to -119 bp. The delGTCA mutation confers reduced luciferase activity to transfected cell lines derived from human ovarian and liver neoplasms. Additionally, human lymphoblasts derived from patients with the Duarte allele have reduced GALT mRNA. We conclude that the human GALT gene is regulated in the first -165 bp of its promoter region by positive regulators of GALT gene expression. The -119 to -116delGTCA reduces hGALT transcription resulting in reduced GALT activity in the Duarte allele.

Endoscopically assisted facial suspension for treatment of facial palsy

Static suspension remains an option for certain patients with facial paralysis. Endoscopically assisted facial suspension obviates the need for a counter-incision at the oral commissure to distally inset the fascia lata graft as described in the standard technique. The endoscopic technique is simple, allows secure placement of perioral fascial strips, and can be performed as an outpatient.

Arterial vascular anatomy of the umbilicus

The rare occurrence of umbilical necrosis after performance of a transverse rectus abdominis muscle (TRAM) flap prompted this investigation into the specific arterial anatomy of the umbilicus using multiple anatomic techniques. Sixteen fresh cadavers were studied by using dissection of blue latex-injected specimens, radiography of barium latex-injected specimens, and selective ink injection of individual perforators. It was discovered that the umbilicus receives arterial inflow by means of three distinct deep sources in addition to the subdermal plexus. These deep sources are (1) the right and left deep inferior epigastric arteries that each give off several small branches, and a large ascending branch, which courses between the muscle and the posterior rectus sheath passing directly to the umbilicus; (2) the ligamentum teres hepaticum; and (3) the median umbilical ligament. The clinical implications of this study are that the umbilicus should have robust arterial inflow if only one rectus muscle is removed, such as during a unilateral TRAM flap, because the contralateral side should still provide large direct vessels from the deep inferior epigastric arteries to the umbilicus. During bilateral TRAM elevation, all of the large arterial sources are removed from the umbilical inflow and circulation must depend on small vessels from the ligamentum teres and median umbilical ligament. Care should be taken in this latter clinical situation to preserve these sources of blood flow during umbilical flap creation.

Percutaneous diagnostic peritoneal lavage using a Veress needle versus an open technique: a prospective randomized trial

OBJECTIVE

To prospectively compare the speed, sensitivity, complications, and technical failures of percutaneous diagnostic peritoneal lavage (DPL) using a Veress needle versus open DPL.

METHODS

One hundred seventy-six blunt trauma patients requiring DPL were prospectively randomized to undergo either open DPL using a standard technique or percutaneous DPL using an 18-gauge Veress needle to penetrate the peritoneal cavity, with the lavage catheter then being inserted over a guide wire.

RESULTS

Mean time to successful placement of the lavage catheter for the percutaneous Veress needle technique was 2.73 minutes versus 7.28 minutes for the open DPL technique (p < 0.001). Sixteen percent of open lavage procedures took more than 11 minutes; the majority (60%) of Veress needle lavage procedures took less than 2 minutes. There were no false-negative findings in either group, and there was one false-positive result in each group. A wound infection after an open DPL was the only complication. Poor return of lavage fluid (<200 mL) accounted for most technical failures; this was more prevalent with the percutaneous method (11.2%) than with the open technique (3.8%) (p < 0.05).

CONCLUSION

The percutaneous DPL method using a Veress needle is significantly faster than the open DPL method. The Veress needle lavage was as safe and as sensitive as the open lavage; however, technical failure occurred more frequently with the Veress needle lavage than with the open DPL.

Reconstruction of the toddler diaphragm in severe anterolateral congenital diaphragmatic hernia with the reverse latissimus dorsi flap

The management of infants with severe congenital diaphragmatic hernia (CDH) continues to evolve. When a prosthetic patch is placed in the neonatal period for pleuroperitoneal separation, it ultimately will require a subsequent reconstruction for progressive pulmonary or abdominal symptomatology. The reverse latissimus dorsi (RLD) flap has been used for reconstruction in only several reports in the last 12 years. In this paper, a patient with severe anterolateral CDH is reconstructed with the RLD flap on an elective basis at 2 years of age. Elective repair was performed for the particular indication of chest wall restriction imposed by the nonpliable Gore-Tex patch. In this case, use of the RLD flap alone without the use of synthetic mesh has resulted in satisfactory results with 17 months of follow up.

Transantral endoscopic orbital floor exploration: a cadaver and clinical study

A cadaver and clinical study was performed to determine the value of transantral endoscopy in diagnosis and treatment of orbital floor fractures. Six fresh cadaver heads were dissected using a 30 degree, 4-mm endoscope through a 1 cm2 antrotomy. In the cadaver, the orbital floor and the course of the infraorbital nerve were easily identified. The infraorbital nerve serves as a reference point for evaluation of fracture size; three zones of the floor are described that are oriented relative to the infraorbital nerve. In the clinical study, nine patients with orbital floor fracture initially underwent endoscopy at the time of fracture repair: three patients had comminuted zygomatico-orbital fractures, five had monofragmented tetrapod fractures, and one had an isolated orbital blowout fracture. Endoscopic dissection of the orbital fractures revealed seven fractures with an area > 2 cm2 and two fractures with an area of < 2 cm2. The isolated orbital floor blowout fracture had entrapped periorbital tissue, which was completely reduced endoscopically. A separate patient with a < 2 cm2 displaced fracture also had stable endoscopic reduction. In the remaining seven patients, the endoscopic technique assisted with the floor reconstruction by identifying the precise fracture configuration as well as identifying the stable posterior ledge of the orbital floor fracture. There have been no complications in any of our patients to date. We conclude: (1) Transantral orbital floor exploration allows precise determination of orbital floor fracture size, location, and the presence of entrapped periorbita. The information obtained through endoscopic techniques may be used to select patients who would not benefit from lid approaches to the orbital floor and may possibly eliminate nontherapeutic exploration. (2) Transantral endoscopic orbital floor exploration assists the reduction of complex orbital floor fractures and allows precise identification of the posterior shelf for implant placement. (3) Transantral endoscopic techniques can completely reduce entrapped periorbital tissue caught in a trapdoor type of fracture.

Arterial anatomy of the oral cavity: an analysis of vascular territories

Knowledge of the specific cutaneous or surface regions supplied by constant named arterial sources has allowed for increasing clinical application of flap transfers of tissue. Despite the routine use of intraoral flaps for reconstruction of congenital or acquired defects of the oral cavity and pharynx, no previous investigation has centered on understanding the surface or mucosal arterial territories of the oral cavity. In a cadaver study, six mucosal territories of the intraoral cavity were defined using selective ink and lead oxide injections through named arteries. The anatomical boundaries of these territories are predictable and constant in location for different cadavers. The six contiguous territories are based on the buccal, labial, inferior alveolar, ascending palatine, ascending pharyngeal, and lingual arteries. This study supports the safe vascular basis of existing clinical procedures of the intraoral cavity and may have implications for the design of new intraoral reconstructive procedures.

Bregmatic masses in children

Bregmatic masses often present a challenging diagnostic dilemma. We present two illustrative cases to demonstrate this clinical problem and present our recommendations for evaluation and treatment.

Bregmatic epidermoid inclusion cyst eroding both calvarial tables

Dermoid and epidermoid cysts are uncommon masses in the head and neck region of children. Although the most common location of inclusion cysts in the head and neck is the bregma, masses in this region must be differentiated from midline hemangiomas, lipomas, hematomas, or encephaloceles. Inclusion cysts should be considered in the differential diagnosis of all midline cystic lesions in infants, because, if left untreated, it may lead to devastating complications. We present the case of a slowly enlarging midline mass in a female infant to illustrate the potential for serious sequelae from inclusion cysts.

Air movement around a worker in a low-speed flow field

A knowledge of the air movement around a worker in a low-speed airflow is important in a number of areas: containment testing of fume cupboards; testing of personal dust samplers; testing of LEV effectiveness; and measurement of worker exposure. Measurements of velocity vectors around the upper torsos of manikins and a human in low-speed airflows have been made using a laser Doppler anemometer. Both heated and unheated manikins, as well as a 'breathing' manikin were used. The results show that quite distinctive flow patterns develop with heated and unheated bodies. Comparison of the flows around two- and three-dimensional manikins with that around a human shows that only a three-dimensional heated manikin gives good results. The unheated breathing manikin gave results which were unrepresentative of the real situation. A suitable manikin for use in sampling or testing in low-speed airflows would have a heated, rounded, three-dimensional body of reasonably human dimensions and would be non-breathing and clothed.

Is outpatient laparoscopic cholecystectomy wise?

The authors report a prospective analysis of their experience with 506 consecutive laparoscopic cholecystectomies to examine the appropriateness of outpatient or same-day laparoscopic cholecystectomy. Thirty-eight patients experienced at least one postoperative complication. The complication was clinically evident or suspected in only 4 of these 38 patients within 8 h following surgery. Thirty-nine percent and 76% of complications were clinically detected at 24 and 48 h, respectively. Nausea and vomiting occurred among 32% of all patients on the day of operation and extended into the 1st postoperative day in 10%. Compared to predicted values, forced vital capacity was 61 +/- 5% 1 h postoperatively in 32 patients studied. At 6 and 24 h postoperatively, forced vital capacity was 63 +/- 7% and 66% respectively. Postoperative analgesic medication requirement was determined in 220 patients who were provided with a patient-controlled intravenous morphine analgesia machine with no basal rate. Consumption of morphine was highly variable but substantial on the day of operation: 17 +/- 16 mg. Most complications of laparoscopic cholecystectomy, including life-threatening complications, are not apparent by 8 h postoperatively and may not be apparent at 24 h. The potential for delay in the diagnosis and treatment of complications, variable but substantial analgesic requirements, impaired postoperative ventilation, and postoperative gastrointestinal dysfunction argue for the need to use great caution in selecting patients for outpatient laparoscopic cholecystectomy. Criteria are proposed to identify patients who are safest for outpatient laparoscopic cholecystectomy.

Effector of hemodynamics during laparoscopy: CO2 absorption or intra-abdominal pressure?

Controversy has been raised about the effects of systemic carbon dioxide accumulation versus the intra-abdominal pressure on hemodynamics during laparoscopy. We compared the acid-base and hemodynamic changes during pneumoperitoneum in a randomized cross-over study between CO2 and nitrogen gases to test the hypothesis that the CO2 absorbed during laparoscopy, rather than the 15 mmHg intra-abdominal pressure created, accounted for these changes. Eight adult pigs were anesthetized and ventilated with a fixed minute ventilation. Metabolic function was measured from analysis of expired flow by a metabolic measurement cart. After baseline periods, animals were randomized into two groups, for 2 hr of either CO2 or nitrogen pneumoperitoneum at 15 mmHg intra-abdominal pressure, followed by 1 hr of recovery. After at least a 48-hr recovery period, the experiment was repeated with the other gas. Metabolic data revealed that there was a significant absorption of CO2 gas across the peritoneal epithelium during CO2 pneumoperitoneum. Animals insufflated with CO2 gas experienced a 75% increase in pulmonary CO2 excretion, with significant acidemia and hypercapnia, whereas there were no acid-base disturbances in those with nitrogen insufflation. Oxygen consumption remained essentially unchanged in both groups, even during pneumoperitoneum. CO2 pneumoperitoneum was also associated with systemic and pulmonary arterial hypertension and a reduction in stroke volume of up to 15%. Pneumoperitoneum alone did not compromise hemodynamics. Pneumoperitoneum using CO2 gas during laparoscopy resulted in systemic CO2 absorption across the peritoneum. This led to acidemia, hypercapnea, and depressed hemodynamics. The intra-abdominal pressure routinely used during laparoscopic surgery did not affect metabolic function, acid-base balance, or hemodynamics in the experimental model.

Investigating a single case of Legionnaires' disease: guidance for consultants in communicable disease control

When a single case of legionnaires' disease is reported, it should be investigated to check whether or not it is linked to other cases or part of an outbreak. The investigation includes confirmation of the diagnosis, tracing the patient's movements during the incubation period, and reporting the case to the National Surveillance Scheme for Legionnaires' Disease at the PHLS Communicable Disease Surveillance Centre. If no common factors are identified between the cases and other cases reported previously, no further action is usually required, unless it is suspected that the infection was acquired in hospital. In these circumstances, the individual case and the hospital's water maintenance programme should be reviewed, and a search made for associated cases, because hospital patients are particularly susceptible to infection. Further steps may be necessary if the link with the hospital is confirmed.

Hemodynamic effects of argon pneumoperitoneum

The hemodynamic effects of argon pneumoperitoneum were studied to define its possible role as an alternative gas for intraperitoneal insufflation during minimally invasive surgery. Adult pigs were anesthetized and placed on mechanical ventilation. Parameters measured or determined included mean arterial (MAP), pulmonary arterial (PAP), pulmonary arterial wedge (PAWP), right atrial (CVP), and inferior vena cava venous (IVC) pressures, total excretion of CO2 (VCO2), oxygen consumption (VO2), minute ventilation, and arterial blood gases. Also determined were cardiac output, stroke volume, and systemic vascular resistance all indexed to weight (CI, SVI, SVRI). Data were recorded during a 1-h baseline, 2 h of insufflation with argon gas at a constant pressure of 15 mmHg, and 1 h recovery after desufflation. There was no significant change from baseline in VCO2, VO2, MAP, PAP, PAWP, CVP, PaCO2, or arterial pH. Argon pneumoperitoneum significantly increased systemic vascular resistance index and exerted a depressant effect on stroke volume index and cardiac index by 25% and 30% from baseline values, respectively (P < 0.05). Inferior vena cava pressure increased as a reflection of the intraabdominal pressure. Argon insufflation had no effect on respiratory function. Argon gas may not be physiologically inert, and in patients with cardiovascular disease its effects may be clinically important.

The effects of CO2 pneumoperitoneum on hemodynamics in hemorrhaged animals

BACKGROUND

Carbon dioxide (CO2), the primary gas currently used for pneumoperitoneum, has been known to cause systemic effects on acid-base balance and hemodynamic stability. We studied the hemodynamic effects of CO2 pneumoperitoneum in a hemorrhagic shock model to assess the safety of laparoscopic procedures in acute trauma patients.

METHODS

After 1 hour of baseline, 32 anesthetized adult pigs were randomized into four groups. Group 1 animals had no hemorrhage, serving as a control group. Group 2 animals had a mild hemorrhage of 10 ml/kg/hr. Group 3 animals had a moderate hemorrhage of 20 ml/kg/hr. Group 4 animals had a moderate hemorrhage but were resuscitated with 40 ml/kg of lactated Ringer's solution. All animals were then insufflated to an intraabdominal pressure of 15 mm Hg with CO2 gas for 1 hour. The abdomen was then decompressed, and the animals were observed for another hour. All animals survived hemorrhage. One death each occurred in moderate hemorrhage groups, both near the end of CO2 pneumoperitoneum. These animals were not included in statistical analysis.

RESULTS

In euvolemic animals, CO2 pneumoperitoneum induced hypercapnia (from 34 +/- 1 mm Hg to 48 +/- 1 mm Hg), acidemia (from 7.45 +/- 0.02 to 7.36 +/- 0.02), and a 20% reduction in stroke volume. Mild hemorrhage and CO2 insufflation resulted in a similar degree of acidemia (7.35 +/- 0.01), but moderate hemorrhage and CO2 insufflation led to more severe acidemia (7.26 +/- 0.02). Fluid resuscitation failed to prevent this severe fall in pH (7.30 +/- 0.03) for group 4. PaCO2 was not affected by hemorrhage, but CO2 pneumoperitoneum induced significant hypercapnia in all groups, ranging from 48 +/- 1 mm Hg for euvolemic animals to 52 +/- 1 mm Hg for moderate hemorrhage animals. Stroke volume declined as a function of blood loss, and it was further depressed by CO2 insufflation, to as low as 75% of baseline in mild hemorrhage and 55% of baseline in moderate hemorrhage. Both stroke volume and cardiac index initially responded to large-volume fluid replacement after moderate hemorrhage but quickly decreased to levels comparable to those of unresuscitated animals when CO2 pneumoperitoneum was created.

CONCLUSIONS

Intraperitoneal insufflation with CO2 for diagnostic laparoscopy may be hazardous in acute hypovolemic trauma patients.