First EMBO Young Investigators announced.
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Awards and Prizes↗
Biomedical subjects
D Stephens
Publications and source records attributed to D Stephens.
More noise in the Public Library of Science.
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Data Collection↗
African American single mothers and children in context: a review of studies on risk and resilience.
This paper presents a comprehensive review of research linking single-parent family structure to parenting processes, maternal well-being, and child developmental outcomes among African Americans. The approaches used to study these families, related methodological and conceptual concerns, and the factors linked to maternal well-being, effective parenting processes, family functioning, and child outcomes are addressed. Much work remains to be done on conceptualizing and assessing parenting processes among African Americans in general and single African American mothers in particular. Researchers must examine more carefully the circumstances that foster or impede successful parenting among these mothers. Studies also are needed to disentangle the interactions between economic stress and parenting behavior and to determine the extent to which the findings can be applied to middle-income single African American parents.
Adolescent↗
Pharmacological modulation of human gastric volumes demonstrated noninvasively using SPECT imaging.
Three-dimensional single-photon emission computed tomography (SPECT) imaging allows noninvasive measurement of human postprandial gastric accommodation. The aim of this study was to determine whether 99mTCO4-SPECT demonstrates effects on pre- and postprandial gastric volumes of intravenous (i.v.) erythromycin lactobionate and sublingual isosorbide dinitrate, as predicted from previous literature. Twenty volunteers received no medication (controls), while 12 were randomized to either i.v. erythromycin 2 mg kg-1 over 20 min, or 10 mg sublingual isosorbide. After a 10-min preprandial SPECT measurement, a standard 300-mL, 300-kcal liquid meal was ingested, followed by a 20-min postprandial measurement. Gastric images were reconstructed from transaxial images and total volume was measured using the Analyseeth software system. Fasting gastric volume was greater with isosorbide [223 +/- 14 (SE) mL vs. 174 +/- 9 mL, control; P < 0.05], and postprandial volume was lower with erythromycin [393 +/- 27 mL vs. 582 +/- 17 mL, control; P < 0.05]. The ratio of postprandial over fasting volume and mean difference between pre- and postprandial volumes were significantly lower in both drug groups compared to controls. We conclude that 99mTCO4-SPECT imaging is able to semiquantitatively demonstrate pharmacological modulation of fasting gastric volume and postprandial accommodation in humans.
Administration, Sublingual↗
Validation of a stable isotope gastric emptying test for normal, accelerated or delayed gastric emptying.
To validate a 13C-Spirulina platensis breath test for measurement of accelerated or delayed gastric emptying, we measured gastric emptying of egg containing 13C-S. platensis and 99mTc-sulphur colloid by breath 13 CO2 every 15 min over 3 h and scintigraphy every 15-30 min over 5 h in 57 healthy volunteers. Thirty-three received no treatment, 10 received erythromycin, and 14 atropine. A generalized linear regression model predicted half-emptying time by scintigraphy (t1/2S) from breath 13CO2 (t1/2B) data. Accuracy was assessed by standard deviation (SD) of differences between t1/2S and t1/2B and by receiver operating characteristic (ROC) curves. Regression models using breath samples at baseline, and 45, 90, 105 and 120 min, predicted t1/2B (mean +/- SD) at 118 +/- 59 min, similar to t1/2S (118 +/- 67 min). Correlation between t1/2B and t1/2S was significant (r=0.88; P < 0.0001). Differences between t1/2S and t1/2B were: 18-19.2 min for t1/2 < 70-150 min, and 68.3 min for t1/2 > 150 min. Breath test detected abnormal emptying with a sensitivity of 86% and specificity of 80%. Thus, the 13C-S. platensis test measures gastric emptying t1/2 for solids, which is accelerated or delayed to mimic a range of conditions from dumping syndrome to severe gastroparesis, with high sensitivity and specificity. Additional breath samples are needed to increase sensitivity in detecting accelerated gastric emptying.
Adolescent↗
Children with hypoalbuminemia on continuous peritoneal dialysis are at risk for technique failure.
BACKGROUND: Few data are available on the clinical significance of hypoalbuminemia [serum albumin (SA) <35 g/L] in children with end-stage renal disease (ESRD) on continuous peritoneal dialysis (CPD). This study was conducted to analyze the prevalence of hypoalbuminemia, its predictive factors, and its clinical impact in these children. METHODS: A retrospective analysis was done of 180 patients on CPD over the last 22 years. Patients were excluded from the study if they were on CPD for less than four months or had nephrotic syndrome. Demographic, clinical, and biochemical variables were studied. Children continued on CPD until they received a transplant or were transferred to an adult unit or to hemodialysis as a result of technique failure. The subjects were divided into two groups based on SA levels at last follow-up. RESULTS: A total of 135 children was included. After a mean duration of CPD of 573 +/- 437 (120 to 2960) days, 54 children (40%) were observed to have hypoalbuminemia. Four patients (2.9%) died, 7 (5.2%) continued on continuous cyclic peritoneal dialysis, and 13 (9.6%) were transferred to an adult unit for continuation of CPD. Ninety-five (70.3%) were transplanted, and 16 (11.8%) were transferred to hemodialysis because of technique failure. Children in group I (N = 54, SA <35 g/L), compared with group II (N = 81, SA > or =35 g/L), were younger at initiation of PD, more likely to have hypoalbuminemia at one month and six months after initiation of PD, and have more episodes of peritonitis. No differences were seen between the groups in gender, modality of CPD, body surface area, initial body mass index, and presence of hypertension or acidosis. The only factors predictive of hypoalbuminemia on follow-up were low SA at one month after PD and recurrent peritonitis using multiple logistic regression analysis. Evaluating the clinical impact of hypoalbuminemia, we observed a higher incidence of failed PD in children who had hypoalbuminemia. CONCLUSION: Low SA at one month after PD and recurrent peritonitis are predictive of hypoalbuminemia in children on CPD, which is associated with an increased incidence of CPD failure.
Adolescent↗
Predictors of hospitalization in children with acute asthma.
OBJECTIVE: To identify predictors of long duration of bronchodilator therapy in children with acute asthma. STUDY DESIGN: An emergency department prospective cohort study of 278 children > or =12 months of age, with clinical and socioeconomic parameters collected at baseline and 4 hours after administration of corticosteroids. Patients were classified into short and long therapy groups, with interval from first albuterol dose to initiation of administration every 4 hours < or =12 or >12 hours, respectively. Predictors significant by univariate analysis were examined by multiple logistic regression. RESULTS: Five variables were associated with long therapy (n = 85) versus short therapy (n = 193): previous intensive care unit admission (odds ratio [OR] 7.2, 95% CI = 1.85, 27.7); baseline oxygen saturation < or =92% (OR 2.6, 95% CI = 0.89, 7.4), asthma score > or =6/9 (OR 2.9, 95% CI = 1.9, 4.37), oxygen saturation < or =92% (OR 6.6, 95% CI = 1.34, 32.0), and hourly albuterol dosing interval (OR 4.3, 95% CI = 0.82, 22.12) 4 hours after administration of corticosteroids. Probability of long therapy was 91.8% to 99% for > or =3 predictors, but only 40.6% to 61.8% for individual factors. CONCLUSION: A combination of 3 or more factors predicts long bronchodilator therapy and signals the need for hospitalization. Children with only one predictor can be safely treated in the emergency department or observation unit and reevaluated.
Acute Disease↗
The relationship between structures and in vitro properties of a polyanhydride implant containing gentamicin sulfate.
Laboratory scale injection-molding equipment was utilized to fabricate an implant consisting of poly(FAD:SA 1:1) and 20% (w/w) gentamicin sulfate. Characterizations were performed to determine the molecular weight and glass transition temperature of poly(FAD:SA 1:1). A study was carried out to investigate the relationships between the in vitro performance, morphology, and micro-structures of the molded implants. It was found that implants produced with different structures exhibited different physical integrities in water, i.e., cracking or non-cracking. For the non-cracking implants, a skin-core structure formed by an oriented skin layer was observed under a polarized light microscope. The same morphology was not seen in the cracking implants. The crystal orientation in the skin layer of the non-cracking implants was further identified using a wide-angle x-ray diffraction method (WAXD). No crystal orientation could be found in the cracking implants by WAXD. Furthermore, studies were carried out to evaluate the in vitro drug release for implants showing different degrees of integrity in water. The in vitro drug release of the cracking implants was markedly faster than that of the non-cracking implants due to the pronounced initial drug-burst effect as a result of crack formation in the implants.
Absorbable Implants↗
Severe falciparum malaria in five soldiers from East Timor: a case series and literature review.
Despite chemoprophylaxis, malaria remains a serious threat for large numbers of non-immune soldiers deployed in endemic areas. Five adult cases of severe falciparum malaria are reported. Three cases were complicated by multiorgan failure and one of these patients died from cerebral malaria. These cases serve to highlight issues, in an Australian intensive care unit, associated with the management of severe malaria, an uncommon disease in our country. The need for rapid diagnosis and commencement of appropriate treatment is paramount in preventing further morbidity and mortality. Understanding and management of malaria continues to evolve rapidly. The pathophysiology of acute lung injury, shock and brain injury associated with malaria are examined in light of recent research. This article discusses the current controversies of exchange blood transfusion and the use of the new artemisinin derivatives.
Adolescent↗
EU research guidelines under spotlight.
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News↗
High prevalence of genotypic zidovudine resistance among HIV-infected Canadian children.
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Adolescent↗
Levamisole vs. cyclophosphamide for frequently-relapsing steroid-dependent nephrotic syndrome.
A retrospective analysis comparing the first-time use of levamisole (L) or cyclophosphamide (C) as second-line therapy for children with frequently relapsing, steroid-dependent (FR/SD) nephrotic syndrome, was conducted at our center. The relapse rate and the total cumulative dose of prednisone during the year prior to L/C therapy was compared to that during the year following the institution of therapy with L or C in 51 patients, between July 1992 and June 1997. An analysis of covariance was used to adjust the outcome for differences between the 2 groups of treatment in the year prior to second-line drug initiation. In the L group the mean relapse rate was lowered by 0.28 relapses/patient/month and the mean cumulative dose of prednisone was reduced by 336 mg/m2/month versus 0.32 relapses/patient/month and 387 mg/m2/month in the C group (p = 0.395. p = 0.577). No significant difference in the effectiveness of L vs. C for therapy of FR/SD nephrotic syndrome could be identified in our patients. We conclude that L may be considered an alternative for C as a first second-line agent for these patients.
Adjuvants, Immunologic↗
Patient factors affecting autologous and allogeneic blood transfusion rates in total hip arthroplasty.
Factors that place patients undergoing total hip arthroplasty (THA) at increased risk of receiving an allogeneic or autologous blood transfusion may aid in determining which patients should predonate blood. The records of 354 consecutive patients undergoing THA were retrospectively reviewed to determine patient factors related to transfusion requirement. The risk of transfusion requirement was most strongly correlated with low preoperative hemoglobin level, but also with older age, higher American Society of Anesthesiologists physical status rating, female sex, cemented arthroplasty, and revision surgery. These patients were also least likely to predonate blood, likely because of their comorbid status.
Age Factors↗
Investigation of the in vitro release of gentamicin from a polyanhydride matrix.
Septacin¿trade mark omitted¿ is a sustained release formulation consisting of gentamicin sulfate dispersed in a biodegradable polyanhydride matrix. The polyanhydride matrix is a copolymer of erucic acid dimer (EAD) and sebacic acid in a 1:1 weight ratio. In vitro drug release was performed in both water and pH 7.4 phosphate buffer. The drug release in water was faster than that in the buffer, which was the opposite of what would be expected based upon a faster polymer hydrolysis rate in the buffer. Theoretical treatment of the data using the Peppas model revealed that release in water was anomalous, while the release in pH 7.4 phosphate buffer was diffusion-controlled. Profound bead morphology differences were observed between beads in these two in vitro release media. Cracking was observed in beads in water and swelling with no apparent cracking was seen in beads in buffer. Concurrent monitoring of drug and sebacic acid release indicated that drug release is not via surface erosion. Osmotic effects were found to play little role in the in vitro drug release. There was no spectroscopic evidence of amide formation between the drug and copolymer. Sulfate release was monitored along with drug release and the results indicate that there is ion-exchange occurring during the pH 7.4 in vitro release. It was subsequently demonstrated that gentamicin can form an insoluble salt with EAD. This salt formation explains the slower drug release in pH 7.4 phosphate buffer.
Decanoic Acids↗
Early predictors of poor functional outcome in systemic-onset juvenile rheumatoid arthritis: a multicenter cohort study.
OBJECTIVE: To examine the ability of a previously described set of criteria to predict poor functional outcome in a large, multicenter cohort of children with systemic-onset juvenile rheumatoid arthritis (JRA). METHODS: All children who were diagnosed with systemic-onset JRA since 1980 at the Hospital for Sick Children (Toronto), since 1983 at the Isaac Walton Killam Hospital for Children (Halifax), and since 1981 at the Children's Hospital of Eastern Ontario (Ottawa) were evaluated. Patients were included in the study if they had been evaluated clinically within 6 months of diagnosis and had been followed up for at least 2 years. Patients were divided into 4 cohorts according to their length of followup: 2-4 years, 4-7 years, 7-10 years, and >10 years. Using previously described criteria for destructive arthritis in children with systemic-onset JRA, the patients were classified as either high risk or low risk for poor functional outcome based on the data from their 6-month visit. High-risk patients had active systemic disease (persistent fever or corticosteroid requirement for control of systemic disease) and a platelet count > or =600 x 10(9)/liter. Poor outcome was defined as moderate or severe disability (defined as a score of > or =0.75 on the Childhood Health Assessment Questionnaire) or disease-associated death. RESULTS: Among 122 eligible patients with systemic-onset JRA, we were able to contact 111 (91%) for outcome data. The mean followup period was 7.7 years (SD 3.7). The mean age at outcome assessment was 13.5 years (SD 5.3). There were 51 boys and 60 girls. Twenty-four patients (22%) had moderate-to-severe disability and 2 patients died; these 26 patients were considered to have had a poor outcome. We could determine risk classification for 104 patients. Twenty-four patients (23%) met the criteria for high risk at the 6-month visit. Overall, the risk of a poor functional outcome was significantly higher in the high-risk group (relative risk 3.3, 95% confidence interval [95% CI] 1.73-6.43, P = 0.0004). This risk was most marked in the cohort with > 10 years of followup (relative risk 4.3, 95% CI 1.82-10.29, P = 0.006). CONCLUSION: The presence of active systemic disease at 6 months, as characterized by fever or the need for corticosteroids, and thrombocytosis strongly predicted the development of a poor functional outcome in these patients. This was especially apparent with longterm followup. Our study validates the previously developed prognostic criteria for systemic-onset JRA.
Activities of Daily Living↗
Ambulatory blood pressure monitoring in children: a large center's experience.
Ambulatory blood pressure monitoring (ABPM) is well established in adults and is becoming common in children. We reviewed 190 ABPM studies retrospectively (since 1990) to assess the failure rate, and analyzed the data from 97 patients 5-19 years old (1992-1996) to review the experience gained from the use of this technique in children and adolescents. Seventeen percent (32/190) of studies failed. Most children accepted ABPM, provided it was clearly explained in advance. There were differences between day and night readings of systolic blood pressure (BP), diastolic BP, and heart rate. BP did not correlate with height or weight. "White coat" effect apparently exists in children: clinic systolic BPs were higher than daytime systolic ABPM (no difference in diastolic). Eighty-nine percent (86/97) had an elevated BP load (>30% of readings >95th percentile). The antihypertensive medications of 16% (16/97) of patients were changed after ABPM. The nocturnal fall in BP (expressed as a percentage of the individual mean daytime values) was approximately normally distributed and was independent of age and height. Nocturnal systolic and diastolic dipping were closely correlated. Attenuation of nighttime dipping was observed in children with kidney disease and those with organ transplants. There is a need for normative data for ABPM for North American children. In our study, the technique was useful in selected cases, such as borderline or secondary hypertension, and for therapeutic monitoring when BP control is difficult.
Adolescent↗
Canadian Acute Respiratory Illness and Flu Scale (CARIFS): development of a valid measure for childhood respiratory infections.
Although acute respiratory infection (ARI) is the most frequent clinical syndrome in childhood, there is no validated measure of its severity. Therefore a parental questionnaire was developed: the Canadian Acute Respiratory Illness Flu Scale (CARIFS). A process of item generation, item reduction, and scale construction resulted in a scale composed of 18 items covering three domains; symptoms (e.g., cough); function (e.g., play), and parental impact (e.g., clinginess). The validity of the scale was evaluated in a study of 220 children with ARI. Construct validity was assessed by comparing the CARIFS score with physician, nurse, and parental assessment of the child's health. Data were available from 206 children (94%). The CARIFS correlated well with measures of the construct (Spearman's correlations between 0.36 and 0.52). Responsiveness was shown, with 90% of children having a CARIFS score less than a quarter of its initial value, by the tenth day.
Acute Disease↗