Persistent intermittent fever and productive cough in a young adult.
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Adult↗
Biomedical subjects
S Morrison
Publications and source records attributed to S Morrison.
Plasmacytoma development in mice injected with silicone gels.
Silicone gels derived from commercially obtained implants induce plasmacytomas in 60-70% of highly susceptible BALB/cAn.DBA/2-Idh1-Pep3 congenic mice. In contrast, dimethylpolysiloxane (DMPS) silicone oils with viscosities of 5, 1000 and 12,500 cs fail to elicit these tumors. 1000 cs vinylmethylpolysiloxane is also inactive. Silicone gels, in contrast to the oils, induce a highly inflammatory silicone granuloma. Silicone gels contain chemical components not found in the oils. The chemical component responsible for inducing the permissive environment for plasmacytoma formation has not yet been identified. Silicone gels are well tolerated for long periods of time in mice without adverse effects other than plasmacytoma formation. The response to different gel preparations varies; some are associated with relatively rapid formation of plasmacytomas resembling that seen with pristane, while in others the plasmacytoma formation is extended nearly over a two year period.
Animals↗
Inter- and intra-limb coordination in arm tremor.
Inter- and intra-limb coordination in arm tremor was examined in adult subjects under vision and no vision conditions using accelerometery techniques. The accelerometer data were analyzed using standard time and frequency domain analyses and the regularity of the acceleration time series was determined using an approximate entropy (Ap En) measure. The data analysis was structured to examine the hypothesis that there is a functional compensatory relation between the motion (tremor) of the limb segments in the arm coordination postural pointing task. The results showed that the level of acceleration increased in a proximal to distal direction within a single arm and was symmetrical across homologous arm segments. The frequency analysis showed the established power spectral profiles for each limb segment in postural tremor tasks, but the finger motion included (beyond the normal 8-12 Hz and 20 Hz tremor) a third slower peak at around 2-3 Hz, due possibly to the reactive forces of the other arm links. There was no effect of vision on the level or frequency patterns of accleration in the limb segments. The coordination analysis showed that there was no linkage between the arms in either the time or frequency domain in the execution of this postural task. This result would tend to suggest that the neuronal commands underlying normal tremor are not derived from a common central oscillator within the central nervous system but are organized in a parallel fashion. The strength of the coupling of intra-limb coordination varied according to the particular adjacent limb links. There were significant correlations in the time domain and coherence in the frequency domain in the acceleration signals between upper arm and forearm, and between hand and finger. The phase lag of the arm units within each of these respective segment pairs was close to in phase or 0 deg. Significant coherence in the frequency domain was also evident between upper arm and hand motion, with the phase lag between these segments being close to 180 deg out of phase. The Ap En analysis of the acceleration signals revealed that there was more regularity to the upper arm and hand accelerometer signals than the forearm and finger signals. The findings show that the intra-limb coordination of the arm links in a two-limb postural pointing task is effected by a compensatory synergy organized about the action of the wrist and shoulder joints. This compensatory synergy reduces the coordination of the 4 within-limb degrees of freedom (arm links) to, in effect, a single degree of freedom arm control task that is not coupled in organization to the motion of the other limb or the torso. It is proposed that this coordination solution reduces the degrees of freedom independently regulated for realization of the task goal but preserves independent body segment control in critical degrees of freedom for potential adaptation to postural perturbations.
Adaptation, Physiological↗
Anaesthetic management of labour and delivery in the parturient with mitochondrial myopathy.
PURPOSE: We describe the anaesthetic management for Caesarean section in a parturient with a defect in complex III of the respiratory chain who had increased lactate concentrations at rest and with exercise. CLINICAL FEATURES: We administered effective epidural anaesthesia with lidocaine for Caesarean delivery. The serum lactate concentration was less than the preoperative value both during and after surgery. Shivering during the perioperative period was avoided by administering warm i.v. fluids, warm local anaesthetic solution and epidural meperidine. Pain relief after surgery was provided with i.v. PCA morphine augmented by local infiltration with bupivacaine to fascia and skin edges and epidural injection with meperidine. CONCLUSION: Mitochondrial myopathies are an uncommon group of disorders in which mitochondrial dysfunction leads to clinical disease of muscle and sometimes of other organs with high energy requirements. The management of labour and delivery in women with mitochondrial myopathies should be individualized according to severity of disease and formulated by consultation between attending physicians and the anaesthetist. Epidural analgesia reduces stress and work associated with labour and reduces oxygen demand during labour. However, parturients with defects of the respiratory chain with documented increased lactate concentrations at rest and with exercise are best managed with elective Caesarean delivery with regional anaesthesia to prevent life-threatening lactic acidosis during labour. The association between malignant hyperthermia and these disorders has not been proved, but it appears prudent to consider these women as MH susceptible until definitive data regarding this possible relationship are available.
Adult↗
Determinants of exercise capacity in patients with coronary artery disease and mild to moderate systolic dysfunction. Role of heart rate and diastolic filling abnormalities.
BACKGROUND: To test the hypothesis that diastolic filling abnormalities are an important cause of exercise limitation in some patients with coronary artery disease we assessed the factors limiting exercise capacity in a group of patients with coronary artery disease in whom exercise limitation was greater than expected from the degree of resting left ventricular systolic dysfunction. METHODS AND RESULTS: We assessed the relationship between exercise capacity (maximal oxygen consumption) during erect cycle ergometry, heart rate, radionuclide indices of left ventricular systolic function (ejection fraction) and diastolic filling (peak filling rate, and time to peak filling) during semi-erect cycle ergometry in 20 patients (15 male, five female) who were aged 42-72 years (mean 61 years) and had angiographically proven coronary artery disease and evidence of reversible myocardial ischaemia on thallium scintigraphy. All patients exhibited marked exercise limitation (maximal oxygen consumption 8.7- 22.4 ml.min-1.kg-1--mean 15.9 ml.kg-1.min-1, which was 61.1 +/- 16% of age and gender predicted maximum) due to breathlessness or fatigue rather than angina, in spite of a mean ejection fraction for the group of 46.5% (range 30-67%). We also compared the diastolic filling characteristics of these patients during exercise with 10 healthy controls (age 38-66, mean 58 years; eight male, two female). Comparing diastolic filling characteristics, peak filling rate was higher and time to peak filling shorter both at rest and at peak exercise in controls than patients (peak filling rate 3.1 +/- 0.5 vs 2.2 +/- 0.9 EDV.s-1, P = 0.01 at rest and 8.3 +/- 0.8 vs 5.2 +/- 1.9 EDV.s-1, P < 0.0001 on exercise; time to peak filling 115.2 +/- 29.8 vs 228.9 +/- 71.7 ms, P < 0.0001 at rest and 52.8 +/- 16.2 vs 139.6 +/- 44.8 ms, P < 0.0001 on exercise respectively). On univariate analysis in the patients studied, maximal oxygen consumption was correlated with peak heart rate (r = 0.45 P = 0.04), peak exercise time to peak filling (r = -0.85 P < 0.0001), peak exercise peak filling time rate (r = 0.51 P = 0.019), and the relative increase in cardiac output i.e. cardiac output peak/cardiac output rest (r = 0.58, P = 0.008). There was no correlation between maximal oxygen consumption and resting indices of diastolic filling (peak filling rate and time to peak filling) or with resting or peak exercise ejection fraction. On multiple regression analysis, only peak exercise time to peak filling was significantly related to maximal oxygen consumption. CONCLUSION: We have observed a strong correlation between exercise capacity and indices of exercise left ventricular diastolic filling, and have confirmed previous studies showing a poor correlation with resting and exercise indices of systolic function and resting diastolic filling, in patients with coronary artery disease.
Adult↗
Custodial suicide in Australia: a comparative study of different populations.
Research on custodial suicide has run into immense difficulties in its attempt to identify common characteristics of the suicide-prone inmate. In 1993, Haycock recognized these difficulties and called for comparative research to delineate the different risks posed by different sorts of confined populations. This paper contrasts the characteristics of different categories of confined inmates based on data collected by the Australian Institute of Criminology on deaths in custody within Australia between the years 1980 and 1993, inclusive. This form of research will lead to a greater understanding of the phenomenon of custodial suicide and the establishment of better preventive strategies tailored to the needs of specific groups and organizations.
Adolescent↗
Radiation exposure from diagnostic radiographs in extremely low birth weight infants.
OBJECTIVE: We sought to examine radiation doses received by infants of less than 750 g birth weight from radiographs. METHODS: We examined the radiology records, including radiograph films, of all 25 surviving infants with birth weight less than 750 g admitted to our center during 1991. The standard method of neonatal radiation dose calculation was modified to consider the body size, postnatal growth, and extramedullary hematopoiesis of the extremely low birth weight infant. To determine overall radiation exposure, we calculated an effective dose equivalent, which is the sum of weighed organ dose equivalents. RESULTS: The infants had a mean of 31 radiographys performed, including 17 chest radiographs, 5 babygrams, and 9 abdominal radiographs. The majority of chest radiographs and babygrams were performed in the first month, whereas abdominal radiographs increased during the second month of life. Total-body radiation dose and total effective dose equivalent by the standard and modified methods, respectively, for single exposures ranged from 0.01 to 0.02 millisieverts (mSv) for a chest radiograph, from 0.02 to 0.04 mSv for a babygram, and from 0.02 to 0.03 mSv for an abdominal radiograph. Surface organs icluding the skin, breast, and thyroid received the largest radiation doses. The effective dose equivalent per infant for all radiographs was 0.72 mSv according to the modified method, compared to a total-body dose of 0.40 mSv using the standard method. However, infants with chronic lung disease or necrotizing enterocolitis received up to 1.5 mSv total-body dose, including 3.3 mSv to the breast, 2.5 mSv to the thyroid, and 2.3 mSv to the testes. CONCLUSIONS: Radiation doses received by infants of less than 750 g birth weight are small in comparison with the range of doses that form the basis of risk estimates for cancer.
Body Constitution↗
Wilms' tumor with pulmonary nodules persisting after chemotherapy and radiation.
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Antineoplastic Combined Chemotherapy Protocols↗
Induction of plasmacytomas in genetically susceptible mice with silicone gels.
Silicone gels injected intraperitoneally into strains of mice related to BALB/c develop plasmacytomas in approximately the same numbers and with similar phenotypes as previously obtained with pristane. Silicone gels produce few side effects and are well tolerated for long periods. Silicone gels contain several components that are potentially biologically active: residual vinyl groups and platinum. Microscopic and histological evidence suggests the silicone gel is degraded over a long period of time. Preliminary studies with long chain liquid dimethylpolysiloxanes with viscosities of 1000 cSt and 12,500 cSt have not produced plasmacytomas as yet. The plasmacytomagenic action of the gel appears to be due to the release of liquids from the gel matrix.
Animals↗
Induction of plasmacytomas with silicone gel in genetically susceptible strains of mice.
BACKGROUND: Plasmacytomas can be induced in high frequency in susceptible strains of mice by the intraperitoneal introduction of plastics or paraffin oils, including the chemically defined oil pristane (2,6,10,14-tetramethylpentadecane). These materials persist in the peritoneal cavity, where they induce chronic inflammation during the long periods before plasmacytomas develop. Such plasmacytomas appear to arise from B cells carrying chromosomal translocations that affect c-myc transcription. PURPOSE: Because silicone gels are in widespread medical use and share many of the characteristics of other materials known to be inducers of plasmacytomas, we wished to determine their capacity to induce plasmacytomas in mice. METHODS: In a series of parallel experiments, corn oil, pristane, silicone oil (dimethylpolysiloxane), or silicone gel from commercially obtained mammary implants was injected intraperitoneally into plasmacytoma-susceptible BALB/cAnPt-A and congenic BALB/cAnPt.DBA/2-Idh1-Pep3 mice, as well as into plasmacytoma-resistant C57BL/6N, C3H/HeJ, DBA/2N, and (BALB/c x DBA/2)F1 mice. Mice were examined at least once every 2 weeks for signs of abdominal tumor or weight loss and screened every 4-6 weeks for peritoneal plasmacytoma cells by peritoneal lavage. Tissues were examined by histologic and immunohistochemical techniques. Metaphase chromosome spreads were made from ascitic plasmacytomas without Colcemid treatment, and metaphase plates were G-banded according to standard techniques. The t(12;15) or t(6;15) translocation chromosomes were identified under the microscope in at least five metaphase plates of high banding quality. Mice were autopsied 125-400 days after the injection of test material. Gas chromatography and mass spectrometry were utilized to determine the composition of the silicone oil and silicone gel used in the injections. RESULTS: The silicone gels tested induced plasmacytomas in BALB/cAnPt-A and BALB/cAnPt.DBA/2-Idh1-Pep3 mice. Neither corn oil used as a control nor 1000-centistoke or 12,500-centistoke dimethylpolysiloxane induced plasmacytomas in these mice. The plasmacytomas were transplantable in syngeneic hosts. Cytogenetic studies of 41 silicone-induced plasmacytomas showed that 30 had t(12;15) translocations, eight had t(6;15) translocations, and three had no translocations. CONCLUSIONS: The silicone gels used in mammary implants, which contain a complex mixture of different siloxanes, induced peritoneal plasmacytomas in genetically susceptible mice. Silicone gels provide new chemically defined materials that are effective inducers of plasmacytomas in BALB/cAnPt-A and BALB/cAnPt.DBA/2-Idh1-Pep3 mice. Further studies will be required to determine which of the components of these gels are the active materials.
Animals↗
Radiological case of the month. Neonatal alloimmune thrombocytopenia.
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Cerebral Hemorrhage↗
Immunomorphologic studies of macrophages and MHC class II-positive dendritic cells in the iris and ciliary body of the rat, mouse, and human eye.
PURPOSE: To establish the presence of distinct populations of macrophages and MHC class II (Ia)-positive dendritic cells (DC) in the iris and ciliary body of the rat, mouse, and human eye. METHODS: Iris-ciliary body wholemounts from a variety of rat strains, balb/c mice, and human eyes were investigated by single and double immunohistochemistry, immunoelectron microscopy, and confocal microscopy to determine the phenotype, density, distribution, and location of macrophage and DC populations. RESULTS: Dendritiform and pleiomorphic macrophages were distributed in a regular array within the rat iris and ciliary body stroma (600 to 700 cells/mm2 or 7000 cells per iris). Ia+ DC were distributed in a similar regular network (400 cells/mm2 or 5500 cells per iris) within the iris stroma and ciliary epithelium. In the rat, a strain-dependent variation in the numbers of DC was noted, F344 rats displaying highest numbers of DC (962 +/- 398 cells/mm2) and WAG strain the lowest numbers (285 +/- 218 cells/mm2). Double color immunoperoxidase staining using anti-Ia and anti-pan specific macrophage monoclonal antibodies revealed that macrophages and Ia+ DC are distinct populations with only 5% to 15% overlap. Single immunoperoxidase of mouse iris and ciliary body using anti-pan macrophage and anti-Ia antibodies produced findings identical to those in rat. Preliminary studies of human tissue using confocal microscopy of immunostained whole irides also revealed a regular array of macrophages and MHC class II (HLA-DR)+ dendritiform cells. CONCLUSIONS: The mammalian iris contains rich networks of dendritiform-pleiomorphic macrophages and MHC class II+ DC. These findings suggest that the DC in the tissues lining the anterior chamber represent a rich network of putative antigen presenting cells and are the most likely candidates for transmitting antigen-specific signals from the anterior chamber in vivo and in experimental models such as ACAID: These observations have wide implications for the understanding of the pathogenesis of anterior and posterior uveitis.
Animals↗
Reproducibility of fluorine-18-6-fluorodopa positron emission tomography in normal human subjects.
UNLABELLED: Fluorine-18-6-fluorodopa (FD) positron emission tomography (PET) is established for measuring nigrostriatal dopaminergic function. This is despite the absence of data on the reproducibility of results. METHODS: With an ECAT 953B/31 tomograph, we performed two or three repeated FD PET scans in 10 normal subjects to measure the scan-to-scan variation in the total striatal uptake rate constant (Ki). RESULTS: We found a scan-to-scan standard deviation (s.d.) of 8.7% of the mean. The between-subject s.d. was 26% of the mean, resulting in a reliability coefficient of 90%. Analysis of the variation in the components contributing to Ki showed a reliability varying from 77% to 86% (depending on the different time points analyzed) for emission data measured by the PET camera. The reliability of the blood radioactivity time course, as reflected by the stretch time, varied from 43% to 81%. The overall reliability for the correction of the blood time course for metabolites of FD was 71%. Variation in the blood radioactivity contributed to the variability of Ki by 50% more than the metabolite correction and by 200% more than the emission data. CONCLUSION: The striatal Ki is a reliable measurement; it has a 95% chance of lying within +/- 18% of its value for an individual normal subject.
Adult↗
Concurrent validity of the Cognitive Levels Test with measures of achievement for a sample of referred children and youth.
The present investigation compared the Cognitive Levels Test (CLT) with the Woodcock Reading Mastery Test (WRMT) and Wide Range Achievement Test-Revised (WRAT-R) for 55 children and youth who were referred for remedial/special education services. A comparison of the correlations for the criterion measures for the WRMT and WRAT-R showed a consistent significant positive relationship with the CLT. A repeated measures analysis of variance that compared standard scores of the CLT with those of the WRMT and WRAT-R indicated that significant differences existed between the test scores. Implications with respect to the concurrent validity of the CLT are discussed.
Adolescent↗
Parametric imaging of the rate constant Ki using [18Fluoro]-L-dopa positron emission tomography in progressive supranuclear palsy.
Positron emission tomography (PET) studies using [18F]-L-dopa were carried out in 9 patients with supranuclear palsy and 13 controls. For quantification of PET data a rate constant Ki was calculated for the radiotracer using a graphical method. Corrections for nonspecific activity were performed in both arterial plasma and brain tissue. The purpose of this study was to test the hypothesis that parametric images of the rate constant K mapping can be obtained on a pixel-by-pixel basis using an appropriate mathematical algorithm. Ki values from these parametric images and the graphical approach were compared. Both correlated closely, with y = 0.013 + 0.947*x, r = 0.992 and y = -0.052 + 1.018*x, r = 0.965 in patients and controls, respectively. Contrast measurements were also performed and showed a striking increase in contrast on parametric images. K mapping offers several advantages over the graphical approach, since parametric images are time-independent, i.e. one image represents the quantitative result of the study. In addition, parametric images of the rate constant are normalized to arterial plasma radioactivity and corrected for tissue metabolites. Thus, parametric images of Ki in different individuals can be compared directly without further processing in order to assess the nigrostriatal integrity.
Aged↗
Safety, tolerance, and pharmacokinetics of systemic ribavirin in children with human immunodeficiency virus infection.
Eleven pediatric patients, aged 1 to 10 years and with symptomatic human immunodeficiency virus infection, were treated with 6 or 10 mg of oral ribavirin per kg of body weight daily for 60 days. Safety and pharmacokinetic parameters were monitored; five children had comprehensive pharmacokinetic evaluations. The children tolerated the drug well, and treatment was not associated with any clinically significant adverse effects. Peak concentrations in plasma of 2.5 and 3.0 microM were reached at 90 min after single oral doses of 6 and 10 mg/kg, respectively. The mean systemic availability of oral ribavirin was 42.3%. After 60 days of ribavirin administration, mean trough concentrations in plasma of 2.6 and 4.1 microM were obtained. Ribavirin penetrated well into the cerebrospinal fluid, achieving 70% of the concentration in plasma at steady state.
Acquired Immunodeficiency Syndrome↗
Contribution of water condensation in endotracheal tubes to contamination of the lungs.
We postulated that water condensate in endotracheal tubes (ETTs) transports bacteria in the ETTs into the lungs during mechanical ventilation. Thirty-two ETTs obtained from freshly extubated patients were studied under wet and dry conditions using a physiologic lung model. All bacteria expelled from the ETTs were collected on culture plates positioned beneath the ETT. The lung model was ventilated with saturated air at 37 degrees C over two time periods (60 min each), one in which condensation formation was prevented and the second in which condensation formed within the ETT. A mean of 457.6 colony-forming units (CFU)/h were expelled with condensation compared to a mean of 2.4 CFU/h without condensation. We concluded that bacteria were continuously transported from the ETT into the lungs during mechanical ventilation in water droplets. Prevention of water condensation abolishes this constant bacterial inoculation in a lung model.
Air Microbiology↗
Frontal, temporal, and striatal proton relaxation times in schizophrenic patients and normal comparison subjects.
Spin-lattice (T1) and spin-spin (T2) magnetic resonance relaxation times were examined in frontal, temporal, and striatal regions of 24 patients with schizophrenia and 10 normal comparison subjects. The schizophrenic patients had more prolonged T2 values than did the comparison subjects, particularly in the left temporal cortex and white matter, suggesting tissue pathology.
Adult↗