Precise radiometric age establishes Yarrabubba, Western Australia, as Earth's oldest recognised meteorite impact structure.

The ~70 km-diameter Yarrabubba impact structure in Western Australia is regarded as among Earth's oldest, but has hitherto lacked precise age constraints. Here we present U-Pb ages for impact-driven shock-recrystallised accessory minerals. Shock-recrystallised monazite yields a precise impact age of 2229 ± 5 Ma, coeval with shock-reset zircon. This result establishes Yarrabubba as the oldest recognised meteorite impact structure on Earth, extending the terrestrial cratering record back >200 million years. The age of Yarrabubba coincides, within uncertainty, with temporal constraint for the youngest Palaeoproterozoic glacial deposits, the Rietfontein diamictite in South Africa. Numerical impact simulations indicate that a 70 km-diameter crater into a continental glacier could release between 8.7 × 1013 to 5.0 × 1015 kg of H2O vapour instantaneously into the atmosphere. These results provide new estimates of impact-produced H2O vapour abundances for models investigating termination of the Paleoproterozoic glaciations, and highlight the possible role of impact cratering in modifying Earth's climate.

Techniques used by United Kingdom consultant plastic surgeons to select implant size for primary breast augmentation.

BACKGROUND: Techniques used to estimate implant size for primary breast augmentation have evolved since the 1970s. Currently no consensus exists on the optimal method to select implant size for primary breast augmentation. METHODS: In 2013 we asked United Kingdom consultant plastic surgeons who were full members of BAPRAS or BAAPS what was their technique for implant size selection for primary aesthetic breast augmentation. We also asked what was the range of implant sizes they commonly used. The answers to question one were grouped into four categories: experience, measurements, pre-operative external sizers and intra-operative sizers. RESULTS: The response rate was 46% (164/358). Overall, 95% (153/159) of all respondents performed some form of pre-operative assessment, the others relied on "experience" only. The most common technique for pre-operative assessment was by external sizers (74%). Measurements were used by 57% of respondents and 3% used intra-operative sizers only. A combination of measurements and sizers was used by 34% of respondents. The most common measurements were breast base (68%), breast tissue compliance (19%), breast height (15%), and chest diameter (9%). The median implant size commonly used in primary breast augmentation was 300cc. SUMMARY: Pre-operative external sizers are the most common technique used by UK consultant plastic surgeons to select implant size for primary breast augmentation. We discuss the above findings in relation to the evolution of pre-operative planning techniques for breast augmentation.

RPE angle effects in young and middle-aged adults.

The purpose of this study was to examine contraction intensity and arm abduction angle effects on perceived exertion between healthy young (n=14) and middle-aged (n=13) adults. Subjects participated in three separate experimental sessions during which, maximal (MVC) and sub-maximal (10-90% MVC, 10% increments, random order) arm abduction contractions were performed at one of the following randomly assigned angles: 30, 60 and 90 degrees Perceived exertion was sampled with a modified Borg category-ratio scale following each sub-maximal contraction. Voluntary arm abduction torque was significantly (p<0.05) greatest at 30 degrees , as compared to 60 degrees and 90 degrees , while no significant differences were observed between the young and middle-aged adults. Perceived exertion was significantly (p<0.05) greatest at 90 degrees abduction, as compared to 30 degrees and 60 degrees , and was not different between the two age groups. Power function modeling revealed that perceived exertion was significantly (p<0.05) fit to negatively accelerating non-linear trends for the middle-aged adults at all arm angles and at 90 degrees for the young adults. The findings demonstrated greater ratings of perceived exertion at elevated arm positions, while middle-aged adults displayed a non-linear contraction intensity dependency at the lower arm elevation angles.

The UK primary hypospadias surgery audit 2006-2007.

AIM: To find out what primary hypospadias surgery is being done in the United Kingdom and at what ages patients have surgery. METHODS: On behalf of the British Associations of Paediatric Urologists, Paediatric Surgeons and Plastic, Reconstructive and Aesthetic Surgeons, paediatric surgeons/urologists, plastic surgeons and urologists were asked to record prospectively their data for 12 months, October 2006-September 2007. RESULTS: There were 50 replies (response rate 50%, 79% of plastic surgeons and 40% of paediatric surgeons/urologists). Most patients had distal hypospadias. The total numbers of operations were 814 (paediatric surgeons/urologists), 436 (plastic surgeons) and 5 (one urologist). More than 20 operations a year were performed by 79% of paediatric surgeons/urologists and 35% of plastic surgeons. Both groups used a similar range of single-stage and two-stage operations. Patients' ages at surgery were less than two years for 68% of paediatric surgeons/urologists and two to four years for 60% of plastic surgeons. CONCLUSIONS: In the UK most primary hypospadias surgery in children is performed by paediatric surgeons/urologists and plastic surgeons. Both groups of surgeons use a range of procedures. Many plastic surgeons are low volume operators. Most plastic surgeons operate on children two or more years old. Plastic surgeons should change their hypospadias service. All hypospadias surgeons should contribute to future prospective outcome studies of hypospadias surgery.

Enrichment and immunoprecipitation of 22 kDa human growth hormone spiked into human urine.

Approaches to detect whether an athlete has used growth hormone have been intensely investigated by sport organizations for 20 years. This effort has led to a human growth hormone (hGH) isoform ratio test in serum that has been approved by WADA and deployed at three Olympic Games, although a positive case has yet to be reported. We set out to determine whether the ratio test could be applied to urine. First we investigated various ways to extract hGH from spiked urine. We were able to recover 95% using selective centrifugal concentration. This fraction was then subjected to four different commercially available immunoprecipitation kits. The highest yield was obtained with the Invitrogen Dynabeads Protein G kit. Nevertheless it is apparent that these methods do not recover enough hGH for subsequent analysis by mass spectrometry. With further effort greater recovery of the 22 kDa isoform might be achieved, however it is very unlikely that the 20 kDa isoform could be detected. This method may be significantly improved by the application of both nanoparticle and aptamer technology.

Cerebellar leukoencephalopathy: most likely histiocytosis-related.

BACKGROUND: Histiocytosis, both Langerhans and non-Langerhans cell type, can be associated with cerebellar white matter abnormalities, thought to be paraneoplastic. The associated clinical picture consists of ataxia, spasticity, and cognitive decline. Hormonal dysfunction is frequent. MRI shows cerebellar white matter abnormalities, as well as brainstem and basal ganglia abnormalities. This so-called "neurodegenerative syndrome" may occur years before or during manifest histiocytosis and also years after cure. We discovered similar MRI abnormalities in 13 patients and wondered whether they could have the same syndrome. METHODS: We reviewed the clinical and laboratory information of these 13 patients and evaluated their brain MRIs. Seven patients underwent spinal cord MRI. RESULTS: All patients were isolated cases; 10 were male. They had signs of cerebellar and pyramidal dysfunction, behavioral problems, and cognitive decline. MRI showed abnormalities of the cerebellar white matter, brainstem, basal ganglia, and, to a lesser extent, cerebral white matter. Three patients had spinal cord lesions. Three patients had laboratory evidence of hormonal dysfunction. No evidence was found of an underlying metabolic defect. In two patients biopsy of nodular brain lesions revealed histiocytic infiltrates. CONCLUSIONS: Considering the striking clinical and MRI similarities between our patients and the patients with this neurodegenerative syndrome in the context of proven histiocytosis, it is likely that they share the same paraneoplastic syndrome, although we cannot exclude a genetic disorder with certainty. The fact that we found histiocytic lesions in two patients substantiates our conclusion. Patients with cerebellar white matter abnormalities should be monitored for histiocytosis.

Sensitivity and specificity of decreased CSF asialotransferrin for eIF2B-related disorder.

OBJECTIVE: This is a study estimating diagnostic accuracy of CSF asialotransferrin to transferrin ratio measurement in eIF2B related disorders by using clinical evaluation and EIF2B mutation analysis as the reference standard. eIF2B-related disorder is a relatively common leukodystrophy with broad phenotypic variation that is caused by mutations in any of the five EIF2B genes. There is a need for a simple and clinically valid screening tool for physicians evaluating patients with an unclassified leukodystrophy. METHODS: CSF two-dimensional gel (2DG) electrophoresis analyses to measure asialotransferrin to transferrin ratios were performed in 60 subjects including 6 patients with documented EIF2B gene mutations, patients with other types of leukodystrophy, and patients with no leukodystrophy. RESULTS: All six patients with mutation proven eIF2B-related disease showed low to nearly undetectable amounts of asialotransferrin in their CSF when compared to 54 unaffected controls by CSF 2DG analyses in this study. eIF2B-like patients, with clinically similar presentations but no mutations in EIF2B1-5, were distinguished from patients with mutations in EIF2B1-5 by this biomarker. Patients with mutations in EIF2B1-5 had asialotransferrin/transferrin ratio levels significantly different from the group as a whole (p < 0.001). Using 8% asialotransferrin/transferrin ratio as a cutoff, this biomarker has a 100% sensitivity (95% CI = 52-100%) and 94% specificity (95% CI = 84-99%). CONCLUSION: Decreased asialotransferrin/transferrin ratio in the CSF of patients with eIF2B-related disorder is highly sensitive and specific. This rapid (<48 hours) and inexpensive diagnostic tool for eIF2B-related disorders has the potential to identify patients with likely eIF2B-related disorder for mutation analysis.

Peripheral and central hypomyelination with hypogonadotropic hypogonadism and hypodontia.

We identified four unrelated patients (three female, one male) aged 20 to 30 years with hypomyelination, pituitary hypogonadotropic hypogonadism, and hypodontia. Electron microscopy and myelin protein immunohistochemistry of sural nerves showed granular debris-lined clefts, expanded abaxonal space, outpocketing with vacuolar disruption, and loss of normal myelin periodicity. Reduced galactocerebroside, sphingomyelin, and GM1-N-acetylglucosamine and increased esterified cholesterol were found. This is a clinically homogeneous progressive hypomyelinating disorder. The term 4H syndrome is suggested.

The bacteriology of children before primary cleft lip and palate surgery.

OBJECTIVE: Bacterial infections can complicate any surgery. Knowledge of potentially pathogenic bacterial flora in children with cleft lip and palate allows appropriate risk management, including the need for prophylactic antibiotics. This project reviewed the bacteriology of children before primary cleft lip and palate surgery. DESIGN: A retrospective study of the results of nose, throat, and ear microbiological swabs taken from children, aged 1 to 26 months, before repair of primary cleft lip, cleft palate, or both was carried out. Swabs with Staphylococcus aureus and beta-hemolytic streptococcus were considered positive. RESULTS: From October 1987 to May 2002, 321 primary cleft lip or palate operations were performed in 250 patients. Results from 326 sets of preoperative swabs were available, including five repeat sets from patients whose operations were postponed. There were 235 (72.1%) negative sets and 91 (27.9%) positive sets. Of the positive swabs, 86 sets grew S. aureus, and 10 sets grew beta-hemolytic streptococcus. CONCLUSIONS: Children with unrepaired cleft lip and palate have a significant risk of carrying S. aureus and a small risk of carrying beta-hemolytic streptococci. These risks need to be considered when deciding on protocols for preoperative bacteriology tests and prophylactic antibiotics.

Cellular neurothekeoma in the arm of a child.

Soft tissue tumours of the limb in children are uncommon. We report a cellular neurothekeoma, which presented as a hard, irregular tumour in the upper arm of a 7-year-old child. The differential diagnosis of soft tissue tumours in the upper limbs of children is discussed.

The impact of violent injuries on an NHS plastic surgery unit.

BACKGROUND: Violence and injuries caused by violence appear to be increasing. PATIENTS AND METHODS: A prospective study of violent injuries treated in our unit. RESULTS: Over a 5-month period, 148 (21%) of 704 acute admission patients aged 14 years or more and 11 children had injuries due to violence. The head, neck and hands were the commonest sites of injury. Of the 148 patients, 144 (91%) underwent surgery for their injuries. CONCLUSIONS: Injuries due to violence have a significant effect on the resources of our NHS hospital and probably of all NHS hospitals with acute surgical services.

Speech after repair of isolated cleft palate and cleft lip and palate.

The speech of children with isolated cleft palate (CP) repaired by one surgeon has been compared with the speech of children with some form of unilateral cleft lip and palate (CLP) repaired by the same surgeon. All palate repairs included an intravelar veloplasty. We identified 57 children (5--12 years old) with cleft palates repaired in infancy, of which three patients with other medical problems were excluded. Of the 54 patients, 44 (81%) attended for review (27 CP, 17 CLP). Video recordings were analysed by two speech and language therapists, using the Cleft Audit Protocol for Speech. The CP patients had no evidence of permanent fistulas. Final speech outcomes were similar for CP and CLP patients. Intelligibility was normal in 10 (37%) CP and nine (53%) CLP patients. Mild consistent hypernasality was present in five (18.5%) CP and four (23.5%) CLP patients. No patients had moderate or severe hypernasality or nasal emission. Mild consistent hyponasality was present in five (18.5%) CP and five (29%) CLP patients. Moderate consistent hyponasality was present in one (4%) CP patient. Dysphonia was present in eight (30%) CP and seven (41%) CLP patients. Cleft-type characteristics were noted in 11 (41%) CP and nine (53%) CLP patients. No CLP patients but 10 (37%) CP patients had required a pharyngoplasty (P=0.004, Fisher's exact test). Possible reasons for this (age, cleft type, surgeon and surgery) are discussed.

A survey of the ways master's level nursing students learn the research process.

Because of the need for advanced practice nurses to perform more outcome measurement, a survey was conducted in the fall of 1997 to determine how master's level students learned the research process. Three hundred four surveys were mailed to schools with master's programs, and 222 were returned for a return rate of 73%. Sixty-six percent of the programs surveyed required a thesis and/or a research project. However, there was great variation in the research projects. A comprehensive examination was used to measure research ability by 36 programs (16%), either in conjunction with a thesis or research project or alone. One hundred forty-six programs (66%) offered only one option, be it a thesis, research project, comprehensive examination, or the many other alternative activities described by respondents. Seventy-six programs (34%) offered a variety of options from which students could select. The major differences between the thesis and the research project were related to three issues: a) the nature of the supervision; b) whether the activity was an individual or group project; and c) the amount of participation of the students. Because of the variability of expectations and the ways students are taught research, it was recommended nurse educators determine whether master's level nurse graduates were prepared to conduct outcome measurement and whether the means used to teach the research process were effective considering that endeavor.

Estrogen-androgen for hormone replacement. A review.

OBJECTIVE: To critically examine the role of androgens as part of postmenopausal hormone replacement therapy. STUDY DESIGN: Examination of original reports and reviews obtained by electronic database searches and supplemented by manual search of bibliographies. RESULTS: As compared to estrogens alone, estrogen-androgen therapy may better protect against osteoporosis and increase libido, energy levels and general sense of well-being. However, estrogen-androgen replacement also reduces the beneficial increases in high-density lipoprotein induced by estrogens alone, although this effect may be offset at least partially by decreases in atherogenic triglycerides. The long-term net effect of estrogen-androgen replacement on cardiovascular disease remains unknown. CONCLUSION: Although the literature includes relatively few clinical trials or well-controlled studies and is further limited by the subjective nature of outcomes, such as sexual and psychological function, the available data suggest that for many postmenopausal women, estrogen-androgen replacement may provide benefits beyond those provided by estrogen-only replacement therapy.