Biomedical subjects
Publications and source records attributed to R Hanson.
The diagnosis of Lyme neuroborreliosis requires a high index of suspicion and chronological correlation of the clinical findings and laboratory data. The limitations of serologic tests must be understood. Cerebrospinal fluid anti-Borrelia burgdorferi antibody index is currently the best indicator of Lyme neuroborreliosis.
Translocations involving the mixed lineage leukemia gene (MLL), the human homolog of the Drosophila gene trithorax, are one of the most common genetic alterations in human acute leukemias. Each translocation involving MLL results in loss of one functional copy of MLL and the generation of a chimeric fusion protein with potential dominant negative or neomorphic activity. Mll is a positive regulator of Hox genes, which have been implicated in both axial skeleton patterning and hematopoietic development. Previous studies indicated that Hox gene expression is altered in Mll heterozygous (+/-) and homozygous (-/-) deficient mice. To study the role of Mll in hematopoiesis and to obtain insights into leukemogenesis, we have examined the effects of haplo-insufficiency or absence of Mll by in vitro differentiation of Mll +/+, +/-, and -/- yolk sac progenitor cells. Mll -/- colonies were fewer in number, took longer to develop, and contained fewer cells than their wild-type and heterozygous counterparts. Formation of colony-forming unit-granulocyte, erythroid, macrophage, megakaryocyte (CFU-GEMM), colony-forming unit-macrophage (CFU-M), and burst-forming unit-erythroid (BFU-E) was markedly decreased in Mll -/- cultures, while numbers of colony-forming unit-erythroid (CFU-E), colony-forming unit-granulocyte (CFU-G), and colony-forming unit-granulocyte macrophage (CFU-GM) were essentially unaffected. Despite the decreased numbers of colonies present, Mll -/- cultures showed all cell types without morphologic evidence of maturation arrest. These studies indicate that Mll is required for normal numbers of hematopoietic progenitors and their proper differentiation, especially along the myeloid and macrophage pathways.
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OBJECTIVE: Our purpose was to evaluate cardiac variables, including right and left end-diastolic and end-systolic dimensions by use of M-mode echocardiography during fetal, neonatal (transitional), and infancy periods to understand hemodynamic adaptation during these periods. STUDY DESIGN: Fifty-three fetuses were enrolled in this study. Echocardiography evaluations were started as early as the sixteenth week of gestation and were repeated every 4 to 6 weeks until term, on postnatal days 1 and 2, and at 6 weeks, 6 months, and 12 months of age. End-diastolic and end-systolic measurements were made according to published standards. Mean and SEM for each of the end-diastolic and end-systolic measurements were calculated for each of 11 study periods. Data were analyzed by one-way analysis of variance, corrected for repeated measures, and in the case of right and left ventricular differences paired t tests were used for significance. RESULTS: Left ventricular end-diastolic and end-systolic correlated positively with advancing age (R2 = 0.93, p < 0.0001), right ventricular end-diastolic also correlated with advancing age (R2 = = 0.361, p < 0.05), and right ventricular end-diastolic was significantly larger than left ventricular end-diastolic in utero (p < 0.01), whereas the opposite was true after birth (p < 0.0001). Heart rate significantly decreased with advancing age (p < 0.001), whereas ejection fraction for either the right or the left ventricle did not change significantly with advancing age. CONCLUSION: This suggests that under basal conditions the ventricles can meet the increased demands in cardiac output by increasing ventricular dimensions without having to increase contractility reserve.
OBJECTIVE: To trial and evaluate a system of "on the spot' vaccination for children up to the age of 15 years in the Early Childhood Centres of the Central Sydney Area Health Service, at the Royal Alexandra Hospital for Children and in a number of general practices in the area. METHODOLOGY: A brief questionnaire was used to collect data from parents and health care professionals about the child's vaccination status and vaccines given "on the spot'. RESULTS: Over an 8 week period in August-September 1993, 5162 questionnaires were completed; 71% of children were up to date with their vaccination. If Haemophilus influenzae type b vaccine, which had been introduced only 2 months before commencement of the study, was excluded, 84% of the children were up to date. A total of 441 children were given 663 vaccinations "on the spot'. Very few children were too ill to be vaccinated (6%). However, only 30% of those who needed vaccination "on the spot' actually received it (441 of 1480), and only 41% (24 of 58) of a subset of those who were not vaccinated were known to have complied 1 month later. Children attending Early Childhood Centres were younger than children attending general practices or the hospital. CONCLUSIONS: A high proportion of children who attended for routine or acute health care had vaccinations overdue (30%). If this scheme could be continued and expanded it would have an important impact on vaccination coverage, and hence on the incidence of vaccine-preventable diseases.
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We studied the effect of 123I-labeled estrogen (123I-E) in estrogen receptor (ER)-rich cells in culture and in cell free model systems in vitro to elucidate the nature of the radiotoxicity for ER + cells of estrogens containing nuclides which emit Auger electrons. In cells the 123I-E caused a dose-dependent, unlabeled estrogen-inhibitable induction of chromosome aberrations. A dose of about 1000 decays per cell, which is approximately the mean lethal dose for these cells, resulted in an average of 1 chromosome break per cell. This supports the hypothesis that the lethal lesion induced by 123I-E is a chromosome break. Incubation of 123I-E/ER complex, but not 123I-E alone, with 27-mer duplex estrogen response element (ERE) DNA produced a dose-dependent cleavage of the ERE. However, we were unable to detect any fragmentation of either the 66 kDa full length ER in cell extracts or a purified 31 kDa hormone binding domain when incubated with excess 123I-E. Thus it appears that 123I-E effects its radiotoxicity by binding to ER, associating with ERE DNA and, by directing high LET radiation to DNA, inducing lethal chromosome breaks.
OBJECTIVE: To improve documentation for children presenting to the Emergency Department (ED) of The Children's Hospital with acute asthma. METHODOLOGY: In phase I, the documentation process was analysed using a standard total quality management (TQM) approach to identify specific problems leading to poor documentation. Fifty-two medical records of children presenting over a 3 week period were reviewed for nursing and medical documentation. A set of minimum criteria, consistent with the Paediatric Asthma Management Plan, were established for documentation by both medical and nursing staff. Following dissemination and education, compliance with documentation was evaluated and compared to an asthma survey performed in the ED in 1991. In phase II, a specific proforma for medical assessment was developed and 80 medical records of children presenting over a 3 week period were reviewed. Fifty-two (65%) with completed proformas were evaluated. The outcome measure was the documentation rate for minimum criteria established by TQM process. RESULTS: In phase I, nursing compliance with documentation ranged from 46% for signs of respiratory distress to 83% for a past history of asthma and 100% for pulse rate. Doctors were similarly poor at documenting essential elements such as severity (31%), palpable pulsus paradoxus (29%), the child's usual doctor (46%) and follow-up arrangements (21-56%). In phase II, the documentation of the severity of acute asthma (42%) and of the child's usual doctor (42%) remained poor but there were statistically significant improvements in documentation of interval medications, palpable pulsus paradoxus, respiratory rate, pre-treatment oximetry, education, follow-up arrangements and communication letters. CONCLUSION: The process of TQM has proved valuable in improving some aspects of documentation of children presenting to ED with acute asthma. It remains to be shown whether improved documentation will result in improved outcome.
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Several studies have reported favorable psychological reactions to predictive testing for Huntington's disease (HD). However, few at-risk persons have been tested, and there is evidence that some at-risk people avoid testing because they fear being unable to cope with the information. Favorable psychological reactions may result from self-selection of persons who believe they are better-equipped to handle "bad news." We surveyed 32 at-risk persons who had considered, but not chosen, testing and 66 persons who had been previously tested. Twelve persons decided not to be tested (No group); 20 persons postponed testing until some later date (Maybe group). Of the two untested groups, a significantly greater number of the No group had not been tested because they anticipated problems associated with their emotional reactions. The persons in the Tested group had less often anticipated problems with their emotional reactions; and among the minority who had anticipated some problems, most did not question their ability to cope. We conclude that the Tested persons are psychologically selected for favorable responses to genetic testing. Surveys of health professionals suggest that a sizable minority would disclose genetic disease risk whether or not people want it. Thus, people who would not choose to be tested might be persuaded to do so, or have results thrust upon them. We should be wary about assuming that the generally favorable reactions to HD testing will continue when testing becomes more widespread, as is likely to happen with simplification of the technology and acceptance of these tests by the medical community.
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OBJECTIVE: Our purpose was to determine left ventricular size and function in obese pregnant patients during the third trimester. STUDY DESIGN: Eight morbidly obese pregnant patients had M-mode echocardiography. None were hypertensive or diabetic at the time of study. A group of 36 normal patients were used as controls. RESULTS: Left ventricular end-diastolic dimension, fractional shortening, and cardiac index were not significantly different between the two groups. Left atrial size, left ventricular wall thickness, interventricular septal thickness, and left ventricular mass were greater in the obese group. The radius-to-wall thickness ratio was significantly smaller in the obese group. CONCLUSIONS: (1) Left ventricular dimension and function in obese patients was similar to that of nonobese patients. (2) The left ventricle was found to be significantly hypertrophied in obese patients. Left ventricular reconfiguration appears to be important in preserving left ventricular function. Whether these changes are specific to pregnancy or secondary to maternal obesity remains to be determined.
OBJECTIVE: Our purpose was to document noninvasively the effect of sickle cell disease on left ventricular systolic and diastolic function during the third trimester of pregnancy. STUDY DESIGN: Fifteen patients with sickle cell disease underwent a two-dimensional M-mode echocardiography obtained using the long axis with the cursor placed at the level of the tip of the mitral valve. All studies were performed with the patient in the left lateral decubitus. A group of 40 normal pregnant patients served as controls. None of the patients had evidence of cardiovascular disease. Left atrial and ventricular dimensions and mass were calculated and averaged. Left ventricular systolic and diastolic function were assessed. RESULTS: Pregnant patients with sickle cell disease had a significant enlargement of the left ventricular end-diastolic dimension, posterior wall, interventricular septum, and ventricular mass than the control group. Although heart rate and fractional shortening were not different between the two groups, stroke volume and cardiac output were higher in patients with sickle cell disease. This was mostly because of enlargement of left end-diastolic dimension. Ventricular diastolic function was different in patients with sickle cell disease, resulting in an increase in the duration of the rapid filling. CONCLUSION: Left ventricular systolic function in patients with sickle cell disease was not affected in spite of a marked ventricular hypertrophy and ventricular enlargement. Diastolic function, however, was lower in the sickle cell group, which indicates a decrease in ventricular compliance. These patients had a higher cardiac output than did a normal pregnant group in the third trimester. This was accomplished by increasing ventricular size without increasing heart rate or fractional shortening.
Children aged 1 month to 14 years admitted to the Royal Alexandria Hospital for Children during a 10 month period with suspected meningitis were studied prospectively. The aims were to determine how often lumbar puncture (LP) was delayed or never done, in relation to the outcome of all children, in order to determine the risks of LP and the risks of not doing LP. Of 218 children with suspected meningitis, LP was performed immediately in 195 (89.4%). Meningitis was diagnosed in 49 of these (bacterial 18, viral 31). No child developed cerebral herniation due to immediate LP. There were 11 traumatic taps and two children required repeated attempts. Lumbar puncture was delayed, but performed at a later time in 17 children, of whom three had proven bacterial meningitis, 1 had presumed bacterial meningitis but no organism was detected and 13 had alternative diagnoses. Six children never had an LP, although ventricular cerebrospinal fluid was obtained from two. Four of these six children had presumptive bacterial meningitis, one had tuberculous meningitis presenting with acute hydrocephalus and diagnosed post-mortem, and one had a very poor neurological outcome and no final diagnosis was reached. Of the 27 children with bacterial meningitis, LP was performed immediately in 18, or two-thirds. There were only minor adverse effects of immediate LP. Delayed LP probably resulted in failure to identify the organism in one child with bacterial meningitis, but did not adversely affect outcome in any child. Of the six children in whom LP was never performed, in only one was no final diagnosis reached.(ABSTRACT TRUNCATED AT 250 WORDS)
This paper presents a review of the patient complaints and those who walked out prior to receiving care in the Accident and Emergency (A&E) Department of the Children's Hospital, Camperdown. The walkout rate was 1.7% (424/27,082) in 1992. Walkouts were greatest in winter when the department was busiest, peak period being between 2000 and 0200 hours. The waiting time was presented as the main reason for walking out. Most parents were prepared to wait the advertised waiting time before leaving. The presenting complaints of children who were not seen covered a spectrum of illnesses with the potential for significant morbidity. The majority, however, were triaged as non-urgent cases. Despite attempts to follow up on walkouts, the outcome for 53% of patients was unknown. Written complaints were fewer in number and tended to focus more on the quality of care (66.6%). There were few recorded compliments. With the increasing customer focus on health, greater attention needs to be given to system failures.
OBJECTIVES: We attempted to quantify noninvasively blood flow of the middle cerebral artery in human fetuses during five distinct periods. STUDY DESIGN: Twenty normal fetuses had color pulsed Doppler ultrasonography of the middle cerebral artery. A total of 68 studies were successfully done and are reported. The Doppler sample was placed as parallel to the direction of the vessel flow as possible. All waveforms were recorded on a strip chart at a preset speed of 100 mm/sec. Six Doppler waveforms were digitized for the time velocity integral (area under the curve is equal to time velocity integral) and averaged. Middle cerebral blood flow was obtained by multiplying the time velocity integral of the Doppler curve by the cross-sectional area of the vessel. The combined cardiac output was obtained by adding the right and left ventricular outputs, which were obtained by multiplying the time velocity integrals by the area of the corresponding annuli. Analysis of variance for repeated measurements was used to determine significance. RESULTS: The diameter of the middle cerebral artery, the time velocity integral, and the peak flow velocity of the Doppler waveform increased significantly with advancing gestational age. Blood flow to the middle cerebral artery ranged from 23 ml/min at 19 weeks to 133 ml/min at term. Resistivity index values were not correlated with advancing gestational age. The percent of the cardiac output to one of the two middle cerebral arteries remained constant throughout gestation with a range between 3% and 7%. CONCLUSIONS: (1) Time velocity integral, peak flow velocity, diameter, and blood flow of the middle cerebral artery increased significantly with gestational age; (2) the percent of the total cardiac output to the middle cerebral artery does not significantly change with gestational age.
OBJECTIVE: Our purpose was to assess fetal central and regional hemodynamics in normal fetuses using two-dimensional, range-gated pulsed Doppler echocardiography in pregnant women on chronic baby aspirin regimen (87 mg). STUDY DESIGN: Fifteen fetuses exposed to maternal chronic ingestion of baby aspirin were compared with 26 control fetuses. Longitudinal studies of the umbilical artery waveform and blood flow through the fetal right and left ventricles were obtained every 4 weeks during gestation in a group of fetuses exposed to daily maternal intake of 87 mg of aspirin. Pulsed Doppler waveforms were obtained below the tricuspid and mitral valves, at the level of the descending aorta (below the ductus), and at the level of the fetal renal artery as it enters the kidney. All tracings were recorded on a strip chart and analyzed with a digital light-pen and graphic overlay system. Peak systolic velocity and minimal diastolic velocity were obtained for the umbilical and fetal renal artery. Peak flow velocity and velocity time integral of the pulsed Doppler waveforms of the atrioventricular valves were calculated. Acceleration time/ejection time ratio was obtained for the descending aorta. RESULTS: No significant differences were found among the two groups in either central or regional circulation. CONCLUSION: Chronic daily maternal ingestion of baby aspirin does not significantly affect the central and regional circulation of the fetus.