To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Hypotension is an adverse event that may be related to systemic exposure of milrinone; however, the true exposure–safety relationship is unknown.
Using the Pediatric Trials Network multicentre repository, we identified children ≤17 years treated with milrinone. Hypotension was defined according to age, using the Pediatric Advanced Life Support guidelines. Clinically significant hypotension was defined as hypotension with concomitant lactate >3 mg/dl. A prior population pharmacokinetic model was used to simulate milrinone exposures to evaluate exposure–safety relationships.
We included 399 children with a median (quarter 1, quarter 3) age of 1 year (0,5) who received 428 intravenous doses of milrinone (median infusion rate 0.31 mcg/kg/min [0.29,0.5]). Median maximum plasma milrinone concentration was 110.7 ng/ml (48.4,206.2). Median lowest systolic and diastolic blood pressures were 74 mmHg (60,85) and 35 mmHg (25,42), respectively. At least 1 episode of hypotension occurred in 178 (45%) subjects; clinically significant hypotension occurred in 10 (2%). The maximum simulated milrinone plasma concentrations were higher in subjects with clinically significant hypotension (251 ng/ml [129,329]) versus with hypotension alone (86 ng/ml [44, 173]) versus without hypotension (122 ng/ml [57, 208], p = 0.002); however, this relationship was not retained on multivariable analysis (odds ratio 1.01; 95% confidence interval 0.998, 1.01).
We successfully leveraged a population pharmacokinetic model and electronic health record data to evaluate the relationship between simulated plasma concentration of milrinone and systemic hypotension occurrence, respectively, supporting the broader applicability of our novel, efficient, and cost-effective study design for examining drug exposure–response and –safety relationships.
Gender is a highly salient and important social group that shapes how children interact with others and how they are treated by others. In this Element, we offer an overview and review of the research on gender development in childhood from a developmental science perspective. We first define gender and the related concepts of sex and gender identity. Second, we discuss how variations in cultural context shape gender development around the world and how variations within gender groups add to the complexity of gender identity development. Third, we discuss major theoretical perspectives in developmental science for studying child gender. Fourth, we examine differences and similarities between girls and boys using the latest meta-analytic evidence. Fifth, we discuss the development of gender, gender identity, and gender socialization throughout infancy, early childhood, and middle childhood. We conclude with a discussion of future directions for the study of gender development in childhood.
Background: High volumes, ill patients, and steep learning curves can make neurosurgical rotations challenging for medical students. Furthermore, existing rotations often lack neurosurgery-specific orientation materials and level-appropriate pre-reading resources reducing the educational yield of short rotations. This is compounded by the lack of mandatory neurosurgical rotations across medical schools. We hypothesized that a “Neurosurgery Clerkship Manual” covering key orientation, knowledge, and practical topics would enhance educational experiences and generate sustained knowledge retention. Methods: Students rotating through neurosurgery at three hospitals were randomized to receive(intervention) or not receive(control) free access to the manual before their rotation. Participants completed surveys before, immediately after, and 4-weeks after the rotation assessing expectations, experiences, and clinically-relevant knowledge. Results: 61 participants were randomized between 2014 and 2017 with 43(70.5%) completing all three questionnaires. Baseline demographics, characteristics, and experiences were not significantly different. Those receiving the manual reported increased rotation enjoyment(p=0.02), decreased stress levels (p=0.05), and a greater feeling of being “part of the team”(p=0.01). There were also reductions in feeling like they were “not learning” (p=0.01). Finally, those receiving the manual demonstrated significantly better knowledge after the rotation (91.6%vs80.9%;p=0.04) which was sustained at 4-weeks post-rotation (89.2%vs79.0%;p=0.05). Conclusions: A simple and inexpensive clerkship manual can improve the neurosurgery rotation experience and knowledge retention for medical students.
The goal of this research was to identify, summarize, and evaluate pediatric disaster preparedness resources in the United States and to identify areas that need improvement or further development. Using standard literature, gray literature and website reviews, relevant resources were identified and the 50 most relevant resources were studied in depth. Each resource was given a grade of A, B, or C based on content, format, quality, and thoroughness. These resources were divided into 3 categories: (1) hospital resources, (2) school resources, and (3) training/education resources. Half of the 50 resources (25) were given a grade of A, indicating the highest level of quality and thoroughness, with pertinent information presented in a clear format. Sixteen of the resources were given a rating of B, while 9 of the resources were given a rating of C. Over 60% of the resources did not contain culturally sensitive information and more than 60% of the resources did not contain preparedness information for children with disabilities. Resources specific to hospitals and schools were limited in number and quality available, while training/education resources were widely available. In addition, 60% of resources were not specific to schools, children’s hospitals, or to certain occupations (ie, nurses, doctors, teachers, principals). Based on these results, gaps in cultural sensitivity were identified and limitations in resources for children with disabilities and for schools and hospitals currently exist. All these areas require further development in the field of pediatric disaster preparedness (Disaster Med Public Health Preparedness. 2019;13:330–337)
Background: CAS is reported to have higher complication rates in elderly compared to younger patients. This effect may be a surrogate for unfavourable anatomy (tortuosity, arch/access vessel atheroma burden) for endovascular treatment. We report our experience with 42 highly selected patients with favourable anatomy in spite of age. Methods: From a cohort of 217 consecutive patients undergoing CAS at St Michael’s Hospital from 2010-2016, stroke and a composite outcome of stroke, MI or death at 30 days post procedure was recorded. We compared outcomes in patients below and above the age of 75. Results: In 217 patients, 175 (80.7%) were below and 42 (19.3%) were above age 75 years. The stroke rate was 1.7% (n=3) and 2.4% (n=1), for patients below and above age 75 years respectively (p=0.58). The composite outcome rate was 4.0% (n=7) and 4.8% (n=2) for patients below and above age 75 years respectively (p=0.69). Conclusions: Patients without high-risk anatomic features were selected for CAS treatment. In this selected group, outcomes for those older than 75 years are comparable to the younger age category. Complication rates were comparable to the results in major randomized symptomatic carotid trials.
Background: On imaging, thrombosed aneurysms can be mistaken for tumor with potentially disastrous consequences. Methods: We present two cases of aneurysms mimicking tumor. Results:Patient 1 (6 months of left-sided facial weakness): MRI demonstrated a 3.3 cm, T1-isotense, T2-hypertense heterogeneous enhancing mass favored to represent a CPA schwannoma. Biopsy revealed a thrombosed aneurysm. DSA subsequently revealed an area of contrast penetration, treated by parent artery (AICA) obliteration. Two-year follow-up revealed stable occlusion with reduced mass effect. Patient 2 (1 year of headaches): Imaging demonstrated an extra-axial T1-mixed, T2-hyperintense heterogeneously enhancing mass in the left CPA adjacent to the vertebral artery, enlarging from 1.7 cm to 3.2 cm over 2 years. DSA revealed slow, crescentic filling with suggestion of arborisation distally. Patient deteriorated due to mass effect requiring a VP shunt and passed away from SAH 3 months later. Imaging review revealed crescentic filling of the remnant lumen on CE-MRA and signal voids on T2 in both cases, which may suggest the aneurysm diagnosis. However our cases did not have other features such as lamellated thrombus or pulsation artifact. Conclusions: Central contrast enhancement does not necessarily preclude the diagnosis of thrombosed aneurysm. The possibility of revascularization or penetration of contrast through the thrombus in giant aneurysms needs to be considered.
Background: The CREST trial remains the most influential study regarding choice of treatment modality for carotid revascularization in the modern era. The effect of the CREST trial on patient outcomes and changes to clinical practice are yet to be fully elucidated. Methods: We report a cohort of 217 consecutive symptomatic average risk patients undergoing CAS at St. Michael’s Hospital, between 2010 and 2016. Outcome measures were stroke, MI and death at 30 days post procedure. Of the 217 patients, 42 were above the age of 75 (19%). Results: The 30-day combined stroke, MI and death outcome for all patients was 4.1%. One death occurred (0.46%) in a patient who suffered an MI. One disabling stroke (0.46%) and 3 mild strokes (1.38%) with full recovery by 6 months occurred. Overall 4 patients suffered an MI (1.84%). Conclusions: As a result of the CREST trial in our single institutional experience there has been a clear migration to treating average risk patients using CAS, a treatment previously reserved for high risk patients. In this average risk cohort we report favourable outcomes when compared to the CREST trial as well as the firmly established benchmarks for CEA complications derived from the NASCET trial.
Growth and propagation of fish-infecting microsporidians within cell culture has been more difficult to achieve than for insect- and human-infecting microsporidians. Fish microsporidia tend to elicit xenoma development rather than diffuse growth in vivo, and this process likely increases host specificity. We present evidence that the fish microsporidian, Loma salmonae, has the capacity to develop xenomas within a rainbow trout gill epithelial cell line (RTG-1). Spore numbers increased over a 4 weeks period within cell culture flasks. Xenoma-like structures were observed using phase contrast microscopy, and then confirmed using transmission electron microscopy. Optimization of the L. salmonae-RTG-1 cell model has important implications in elucidating the process of xenoma development induced by microsporidian parasites.
In the management of subarachnoid hemorrhage (SAH), the potential for early complications and the centralization of limited resources often challenge the delivery of timely neurosurgical care. We sought to determine the impact of proximity to the accepting neurosurgical centre on outcomes following aneurysmal SAH.
Using administrative data, we analyzed patients undergoing treatment for aneurysmal subarachnoid hemorrhage at neurosurgical centres in Ontario between 1995 and 2004. We compared mortality for patients receiving treatment at a centre in their county (in-county) versus those treated from outside counties (out-of-county). We also examined the impact of distance from the patient's residence to the treating centre.
The mortality rates were significantly lower for in-county versus out-of-county patients (23.5% vs. 27.6%, p=0.009). This advantage remained significant after adjusting for potential confounders (HR=0.84, p=0.01). The relationship between distance from the treating centre and mortality was biphasic. Under 300km, mortality increased with increasing distance. Over 300km, a survival benefit was observed.
Proximity to the treating neurosurgical centre impacts survival after aneurysmal SAH. These results have significant implications for the triage of these critically ill patients.
Investigations to determine the electrical contact
performance under repeated cycles at low force conditions for
carbon-nanotube (CNT) coated surfaces were performed. The surfaces under
investigation consisted of multi-walled CNT synthesized on a silicon
substrate and coated with a gold film. These planar surfaces were mounted on
the tip of a PZT actuator and contacted with a plated Au hemispherical
probe. The dynamic applied force used was 1 mN. The contact resistance
(Rc) of these surfaces was investigated with the applied force and with
repeated loading cycles performed for stability testing. The surfaces were
compared with a reference Au–Au contact under the same experimental
conditions. This initial study shows the potential for the application of
gold coated CNT surfaces as an interface in low force electrical contact
A survey of microfilaraemia among the population of Vanua Levu, Taveuni and Koro islands in northern Fiji was conducted in 1968 and 1969 as a prelude to a campaign of mass treatment with diethylcarbamazine.
The prevalences of microfilaraemia were found in the more moist conditions of Taveuni and Koro and on the windward southern side of Vanua Levu to be higher than on the drier northern side of Vanua Levu. On both sides of Vanua Levu prevalences were lower inland than near the coast.
Under apparently similar environmental conditions those of Fijian ethnic origin exhibited a higher prevalence of microfilaraemia than that shown by Indians. This ethnic difference and a difference between the prevalences in male and female Fijians are considered to be due more to higher rates of recovery from microfilaraemia in Indians and Fijian women than to diminished exposure to mosquitoes. Mathematical models have been used as an aid to the interpretation of the data, and, where appropriate, comparison has been made with the prevalence of antibodies to dengue, an arbovirus having the same vectors.
Household infections were analysed by computer techniques. Infections in large households were not proportionately higher than in small households, indicating that transmission was not intrafamilial. The clustering of infections within households, though present, was not marked. Among the occupants of outlying settlements the prevalence of microfilaraemia was relatively low indicating a lower risk of infection due to isolation.
Surveys of arbovirus activity in Fiji were conducted over a 10-year period from December 1959 to December 1969. No arboviruses were isolated from over 200,000 mosquitoes, 9000 ticks, or 575 serum samples. Eight thousand human and 1117 bird, bat and animal sera were tested for haemagglutination-inhibiting arbovirus antibody using a variety of group A, group B and Bunyamwera group antigens. Only a small number of low-titre reactions were found among the non-human sera, but 14% of all human sera were found to contain Group B antibody. The antibody prevalence increased with increasing age, from less than 1 % for persons born since 1950, to 70% for persons born before 1900. The age differences in prevalence could be used to estimate the time and size of previous epidemics. Differences were found in antibody prevalence between the sexes, between ethnic groups and between persons from different regions. These differences could be explained in terms of climate, location and custom.
Historical and serological evidence both suggest that all the antibody detected was due to past exposure to dengue virus. The very high proportion of the population with no dengue antibody makes Fiji a high-risk area for a further dengue epidemic. Dengue virus is known to be active in the Pacific and South-East Asia.
During a filariasis survey conducted in northern Fiji in 1968–9 examinations were made for microfilaraemia, enlarged lymph nodes and elephantiasis. Analysis of the microfilarial densities at different ages and the number of anatomical sites showing lymph gland enlargement or elephantiasis have been used to provide evidence on the clustering of infections and pathogenesis.
Although there is no evidence of clustering of risk of infection, there is evidence favouring the clustering of adult filariae in individuals. Nevertheless the number of sites of lymph node enlargement do not correspond with this finding and statistical evidence suggests that lymph-node enlargement is not necessarily associated with the near presence in the body of adult filariae, whether dead or alive.
Males of Indian ethnic origin showed a higher prevalence of elephantiasis than males of Fijian ethnic origin, but women of either ethnic race showed prevalences lower than those of men.
The onset of elephantiasis at a site does not directly reflect the number of infections sustained in the local area, but it appears that filariasis first induces for a limited period a proneness to elephantiasis. During this period a random and discrete event may induce the onset of elephantiasis. The nature of the event is unknown, but it probably is not trauma.
The microstructure and residual stress of sputter-deposited yttria-stabilized zirconia (YSZ) films are presented as a function of thickness (5–1000 nm), deposition pressure (5–100 mTorr), and post-deposition temperature. The as-deposited residual stress of YSZ ranges from −1.4 GPa to 100 MPa with variations in sputtering conditions. Transitions from compressive to tensile stress are identified with variations in working pressure and film thickness. The origins and variations in as-deposited stress are determined to be from tensile stress due to grain coalescence/growth, and compressive stresses are due to forward sputtering/“atomic peening” of target atoms. The evolution of residual stress with post-deposition annealing shows a tensile stress hysteresis of up to 1 GPa for films deposited at low working pressures. This hysteresis is believed to be due to crystallization and the diffusive relief of compressive stresses initially generated by atomic peening during deposition. Discussion and evaluation of other common residual stress mechanisms are presented throughout.