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Biomedical subjects

J A Anderson

Publications and source records attributed to J A Anderson.

At least 37 records · Page 2Linked to original sources
PubMed2002

Gardner's syndrome - a case report.

Gardner's syndrome is the association of multiple colonic polyps (familial adenomatous polyposis coli - FAP) with sebaceous cysts and jaw osteomas. The significance of this dominantly inherited condition to the dentist is that the colonic polyps usually undergo malignant change by the fourth decade and the extra-intestinal lesions may be apparent before those in the bowel. As such, early detection of multiple jaw osteomas and/or multiple sebaceous cysts (particularly on the scalp) may lead to appropriate further investigation and treatment which might be life saving. Diagnosis of this condition also has implications for other family members.

Adult↗
PubMed2001

Body water compartment measurements: a comparison of bioelectrical impedance analysis with tritium and sodium bromide dilution techniques.

BACKGROUND AND AIMS: This study was undertaken to assess the comparability of body water compartment estimates in healthy volunteers using single and dual frequency bioelectrical impedance analysis (BIA) with established reference methods of tritium and NaBr dilution. METHODS: Total body water (TBW) was estimated in 10 healthy volunteers using single frequency (50 kHz) BIA (Bodystat 1500), dual frequency (5 and 200 kHz) BIA (Bodystat Dualscan 2005) and tritium dilution. Extracellular water (ECW) was measured with dual frequency BIA and NaBr dilution. BIA was performed using distal tetrapolar electrodes in the supine position. Venous blood was sampled for measurement of background concentrations of tritium and NaBr using a beta counter and high performance liquid chromatography respectively. 10 ml tritiated water (3.7 MBq) and 50 ml 5% NaBr solution were then injected intravenously and blood samples taken from the opposite arm every 45 min for 4.5 h for estimation of concentrations of tritium and NaBr. RESULTS: There was good correlation (r(2)=0.76) between estimates of ECW using dual frequency BIA and NaBr dilution, with the former overestimating ECW by approximately 1 L. However, this difference varied systematically with body weight. Although TBW measurements obtained by single and dual frequency BIA correlated well with estimates using tritium dilution (r(2)=0.96 and 0.95 respectively), single frequency BIA underestimated TBW by approximately 1 L and dual frequency BIA by approximately 5 L compared to tritium dilution. CONCLUSION: TBW measurements obtained using the single frequency BIA device were more accurate than those obtained using the dual frequency BIA device. Dual frequency BIA provided a reasonably accurate estimate of ECW.

Adult↗
PubMed2001

Growth and development in rats given recombinant human epidermal growth factor(1-48) as neonates.

To assess effects of supraphysiologic doses of human recombinant epidermal growth factor(1-48) (rhEGF(1-48)) on neonatal rats, 10 litters of Wistar rats/treatment group were given 0 (formulated vehicle), 10, 100, or 1000 microg/kg daily by subcutaneous injection on postnatal days (PND) 1 through 6. Clinical signs, body weight, acquisition of developmental landmarks and reflexes, and behavior were monitored during treatment and for 5 weeks thereafter (to PND 42). A subset of animals was euthanized weekly from PND 7-28 and necropsied. Selected tissues were examined microscopically. Body weight gain at 1000 microg/kg during treatment was significantly less than control. Precocious incisor eruption, eye opening, vaginal opening, and preputial separation occurred at 100 and/or 1000 microg/kg. Acquisition of reflexes (negative geotaxis, wire maneuver, acoustic startle reflex, and visual placing) was delayed at 1000 microg/kg. Acquisition of adult locomotion was also delayed at 1000 microg/kg. These effects were transient, as locomotor activity at PND 28 and 42 did not differ from control. Effects on acoustic-startle responding persisted in females to final assessment on PND 42. Habituation to repeated acoustic stimuli was impaired, as well as response inhibition following a prepulse acoustic stimulus. rhEGF(1-48) induced structural changes in the skin, retina, kidney, oral and nasal mucosa, lung, and liver. Many of these changes were consistent with the expected mitogenic activity of rhEGF(1-48) and were transient in nature, as severity and incidence diminished with time. An exception was changes observed in the retina at 1000 microg/kg (rosettes/folds and focal defects in the outer nuclear/photoreceptor layers) that were still present 3 weeks after termination of treatment. Acceleration of developmental landmarks; suppression of reflexes, behavior, and somatic growth; and mitogenic responses in epidermal tissues have been reported in rodents treated with epidermal growth factor (EGF) derived from various mammalian species. These results demonstrate that a 48-amino acid fragment of human EGF produced by recombinant technology also induces such effects.

Acoustic Stimulation↗
PubMed2001

Understanding homeless adults by testing the theory of self-care.

This article explicates, within a sample of homeless adults, the relationship between self-care agency, self-care, and well-being, while controlling for select basic conditioning factors. Self-care is found to explain 30% of the variance in current well-being. Self-esteem and affect balance, along with the power components of self-care agency, are found to explain 25% of the variance in self-care and, together with select basic conditioning factors, to explain 54% of its variance. Affect is proposed as an energy disposition, a dimension of self-care agency. Recommendations are made to strengthen the homeless individual's self-care agency.

Adaptation, Psychological↗
PubMed2001

Dilution and redistribution effects of rapid 2-litre infusions of 0.9% (w/v) saline and 5% (w/v) dextrose on haematological parameters and serum biochemistry in normal subjects: a double-blind crossover study.

Although hypoalbuminaemia after injury may result from increased vascular permeability, dilution secondary to crystalloid infusions may contribute significantly. In this double-blind crossover study, the effects of bolus infusions of crystalloids on serum albumin, haematocrit, serum and urinary biochemistry and bioelectrical impedance analysis were measured in healthy subjects. Ten male volunteers received 2-litre infusions of 0.9% (w/v) saline or 5% (w/v) dextrose over 1 h; infusions were carried out on separate occasions, in random order. Weight, haemoglobin, serum albumin, serum and urinary biochemistry and bioelectrical impedance were measured pre-infusion and hourly for 6 h. The serum albumin concentration fell in all subjects (20% after saline; 16% after dextrose) by more than could be explained by dilution alone. This fall lasted more than 6 h after saline infusion, but values had returned to baseline 1 h after the end of the dextrose infusion. Changes in haematocrit and haemoglobin were less pronounced (7.5% after saline; 6.5% after dextrose). Whereas all the water from dextrose was excreted by 2 h after completion of the infusion, only one-third of the sodium and water from the saline had been excreted by 6 h, explaining its persistent diluting effect. Impedances rose after dextrose and fell after saline (P<0.001). Subjects voided more urine (means 1663 and 563 ml respectively) of lower osmolality (means 129 and 630 mOsm/kg respectively) and sodium content (means 26 and 95 mmol respectively) after dextrose than after saline (P<0.001). While an excess water load is excreted rapidly, an excess sodium load is excreted very slowly, even in normal subjects, and causes persistent dilution of haematocrit and serum albumin. The greater than expected change in serum albumin concentration when compared with that of haemoglobin suggests that, while dilution is responsible for the latter, redistribution also has a role in the former. Changes in bioelectrical impedance may reflect the electrolyte content rather than the volume of the infusate, and may be unreliable for clinical purposes.

Adult↗
PubMed2000

Hypersulfated low molecular weight heparin with reduced affinity for antithrombin acts as an anticoagulant by inhibiting intrinsic tenase and prothrombinase.

In buffer systems, heparin and low molecular weight heparin (LMWH) directly inhibit the intrinsic factor X-activating complex (intrinsic tenase) but have no effect on the prothrombin-activating complex (prothrombinase). Although chemical modification of LMWH, to lower its affinity for antithrombin (LA-LMWH) has no effect on its ability to inhibit intrinsic tenase, N-desulfation of LMWH reduces its activity 12-fold. To further explore the role of sulfation, hypersulfated LA-LMWH was synthesized (sLA-LMWH). sLA-LMWH is not only a 32-fold more potent inhibitor of intrinsic tenase than LA-LMWH; it also acquires prothrombinase inhibitory activity. A direct correlation between the extent of sulfation of LA-LMWH and its inhibitory activity against intrinsic tenase and prothrombinase is observed. In plasma-based assays of tenase and prothrombinase, sLA-LMWH produces similar prolongation of clotting times in plasma depleted of antithrombin and/or heparin cofactor II as it does in control plasma. In contrast, heparin has no effect in antithrombin-depleted plasma. When the effect of sLA-LMWH on various components of tenase and prothrombinase was examined, its inhibitory activity was found to be cofactor-dependent (factors Va and VIIIa) and phospholipid-independent. These studies reveal that sLA-LMWH acts as a potent antithrombin-independent inhibitor of coagulation by attenuating intrinsic tenase and prothrombinase.

Anticoagulants↗
PubMed2000

Randomised, double blind, placebo controlled study of fluticasone propionate in patients with moderate to severe chronic obstructive pulmonary disease: the ISOLDE trial.

OBJECTIVES: To determine the effect of long term inhaled corticosteroids on lung function, exacerbations, and health status in patients with moderate to severe chronic obstructive pulmonary disease. DESIGN: Double blind, placebo controlled study. SETTING: Eighteen UK hospitals. PARTICIPANTS: 751 men and women aged between 40 and 75 years with mean forced expiratory volume in one second (FEV(1)) 50% of predicted normal. INTERVENTIONS: Inhaled fluticasone propionate 500 microgram twice daily from a metered dose inhaler or identical placebo. MAIN OUTCOME MEASURES: Efficacy measures: rate of decline in FEV(1) after the bronchodilator and in health status, frequency of exacerbations, respiratory withdrawals. Safety measures: morning serum cortisol concentration, incidence of adverse events. RESULTS: There was no significant difference in the annual rate of decline in FEV(1 )(P=0.16). Mean FEV(1) after bronchodilator remained significantly higher throughout the study with fluticasone propionate compared with placebo (P<0.001). Median exacerbation rate was reduced by 25% from 1.32 a year on placebo to 0.99 a year on with fluticasone propionate (P=0.026). Health status deteriorated by 3.2 units a year on placebo and 2.0 units a year on fluticasone propionate (P=0.0043). Withdrawals because of respiratory disease not related to malignancy were higher in the placebo group (25% v 19%, P=0.034). CONCLUSIONS: Fluticasone propionate 500 microgram twice daily did not affect the rate of decline in FEV(1) but did produce a small increase in FEV(1). Patients on fluticasone propionate had fewer exacerbations and a slower decline in health status. These improvements in clinical outcomes support the use of this treatment in patients with moderate to severe chronic obstructive pulmonary disease.

Administration, Inhalation↗
PubMed2000

Improving dietetics education with interactive communication technology.

Changes occurring in health care, education, and technology are altering dietetics education. A model of learnercentered, cooperative, distance education based on interactive online technology is described for use in a dietetic internship. Evaluation of this model includes review of key-feature exams, results of computer attitudes surveys, use of the technology by interns, exit interviews, and performance on the examination for registered dietitians. In a pilot study of the model with 8 subjects, comfort using the Internet improved significantly. Use of interactive communication technology in dietetics education has the potential to improve competency, technological aptitude, professional partnering skills, and lifelong learning skills.

CD-I↗
PubMed2000

How do the 20 top-rated U.S. Medical schools approach women's health?

A follow-up survey of women's health programs at the 20 top-rated U. S. medical schools in 1998 (as identified by U.S. News & World Report) asked how they addressed women's health issues. Results from the 1998 survey are compared with those from the 20 top-rated schools in 1996.

Curriculum↗
PubMed2000

Effect of the murine leukemia virus extended packaging signal on the rates and locations of retroviral recombination.

Reverse transcriptase (RT) switches templates frequently during DNA synthesis; the acceptor template can be the same RNA (intramolecular) or the copackaged RNA (intermolecular). Previous results indicated that intramolecular template switching occurred far more frequently than intermolecular template switching. We hypothesized that intermolecular template-switching events (recombination) occurred at a lower efficiency because the copackaged RNA was not accessible to the RT. To test our hypothesis, the murine leukemia virus (MLV) extended packaging signal (Psi(+)) containing a dimer linkage structure (DLS) was relocated from the 5' untranslated region (UTR) to between selectable markers, allowing the two viral RNAs to interact closely in this region. It was found that the overall maximum recombination rates of vectors with Psi(+) in the 5' UTR or Psi(+) between selectable markers were not drastically different. However, vectors with Psi(+) located between selectable markers reached a plateau of recombination rate at a shorter distance. This suggested a limited enhancement of recombination by Psi(+). The locations of the recombination events were also examined by using restriction enzyme markers. Recombination occurred in all four regions between the selectable markers; the region containing 5' Psi(+) including DLS did not undergo more recombination than expected from the size of the region. These experiments indicated that although the accessibility of the copackaged RNA was important in recombination, other factors existed to limit the number of viruses that were capable of undergoing intermolecular template switching. In addition, recombinants with multiple template switches were observed at a frequency much higher than expected, indicating the presence of high negative interference in the MLV-based system. This extends our observation with the spleen necrosis virus system and suggests that high negative interference may be a common phenomenon in retroviral recombination.

5' Untranslated Regions↗
PubMed2000

Utilization of nonviral sequences for minus-strand DNA transfer and gene reconstitution during retroviral replication.

Minus-strand DNA transfer, an essential step in retroviral reverse transcription, is mediated by the two repeat (R) regions in the viral genome. It is unclear whether R simply serves as a homologous sequence to mediate the strand transfer or contains specific sequences to promote strand transfer. To test the hypothesis that the molecular mechanism by which R mediates strand transfer is based on homology rather than specific sequences, we examined whether nonviral sequences can be used to facilitate minus-strand DNA transfer. The green fluorescent protein (GFP) gene was divided into GF and FP fragments, containing the 5' and 3' portions of GFP, respectively, with an overlapping F fragment (85 bp). FP and GF were inserted into the 5' and 3' long terminal repeats, respectively, of a murine leukemia virus-based vector. Utilization of the F fragment to mediate minus-strand DNA transfer should reconstitute GFP during reverse transcription. Flow cytometry analyses demonstrated that GFP was expressed in 73 to 92% of the infected cells, depending on the structure of the viral construct. This indicated that GFP was reconstituted at a high frequency; molecular characterization further confirmed the accurate reconstitution of GFP. These data indicated that nonviral sequences could be used to efficiently mediate minus-strand DNA transfer. Therefore, placement and homology, not specific sequence context, are the important elements in R for minus-strand DNA transfer. In addition, these experiments demonstrate that minus-strand DNA transfer can be used to efficiently reconstitute genes for gene therapy applications.

3T3 Cells↗
PubMed1999

Decreased leukotriene C4 synthesis accompanies adherence-dependent nuclear import of 5-lipoxygenase in human blood eosinophils.

The enzyme 5-lipoxygenase (5-LO) catalyzes the synthesis of leukotrienes (LTs) from arachidonic acid (AA). Adherence or recruitment of polymorphonuclear neutrophils (PMN) induces nuclear import of 5-LO from the cytosol, which is associated with enhanced LTB4 synthesis upon subsequent cell stimulation. In this study, we asked whether adherence of human eosinophils (EOS) causes a similar redistribution of 5-LO and an increase in LTC4 synthesis. Purified blood EOS examined either in suspension or after adherence to fibronectin for 5 min contained only cytosolic 5-LO. Cell stimulation resulted in activation of 5-LO, as evidenced by its translocation to membranes and LTC4 synthesis. As with PMN, adherence of EOS to fibronectin for 120 min caused nuclear import of 5-LO. Unexpectedly, however, adherence also caused a time-dependent decrease in LTC4 synthesis: EOS adhered for 120 min produced 90% less LTC4 than did cells adhered for 5 min. Adherence did not diminish the release of [3H]AA from prelabeled EOS or reduce the synthesis of the prostanoids thromboxane and PGE2. Also, inhibition of LTC4 production caused by adherence could not be overcome by the addition of exogenous AA. Adherence increased, rather than decreased, LTC4 synthase activity. However, the stimulation of adherent EOS failed to induce translocation of 5-LO from the nucleoplasm to the nuclear envelope. This resistance to activation of the nuclear pool of 5-LO with diminished LT production represents a novel mode of regulation of the enzyme, distinct from the paradigm of up-regulated LT synthesis associated with intranuclear localization of 5-LO observed in PMN and other cell types.

Arachidonate 5-Lipoxygenase↗
PubMed1999

Detection of intracellular phosphorylated STAT-1 by flow cytometry.

We have applied flow cytometry to the investigation of interferon-gamma activation of human monocytes. This approach uses monoclonal antibodies that distinguish between the native and phosphorylated forms of STAT-1. It enables rapid and quantitative assessment of STAT-1 phosphorylation on a discrete cell basis and is both more sensitive and less time consuming than immunoblotting. Furthermore, it allows for discrimination between a mixture of cells that differ in their response to interferon-gamma. This approach should allow for the evaluation of different intracellular signaling pathways using a combination of monoclonal reagents that are specific for native and activation modified proteins. Application of this form of testing should prove valuable in screening for signaling defects in selected patients with recurrent infections. In addition, this technique should permit dissection of a full range of cellular signaling pathways at the protein level.

DNA-Binding Proteins↗
PubMed1999

What comprises appropriate therapy for children/adolescents with rhabdomyosarcoma arising in the abdominal wall? A report from the Intergroup Rhabdomyosarcoma Study Group.

PURPOSE: The aim of this study was to define clinical features and determine the best therapy for patients with rhabdomyosarcoma (RMS) of the abdominal wall. METHODS: We examined the demographic, clinical features, therapy (especially surgical), and outcome of 34 patients. Patients received combination chemotherapy after complete surgical resection (group I, n = 14; 41%); resection with microscopic residual followed by local irradiation (RT; group II, n = 8; 24%); partial resection or biopsy only plus RT with gross locoregional residual tumor (group III, n = 4; 12%); or biopsy only plus RT with metastatic disease (group IV, n = 8; 24%). Patients with group I or group II tumors had undergone partial abdominal wall resection (ie, involved muscle only with preservation of peritoneum, n = 11) or complete abdominal wall resection (n = 7). Four additional patients had groin lesions. RESULTS: Thirty-four children or adolescents with abdominal wall RMS (about 1% of all patients) were treated on Intergroup Rhabdomyosarcoma Study I (IRS-I) through IRS-IV. Overall, adolescents comprised 14 of 34 eligible patients (41%), and 10 of 14 (71%) adolescents had alveolar or undifferentiated tumors versus 8 of 20 (40%) younger children (P= .07). Failure-free survival (FFS) rate and survival rate at 5 years was 65%. Treatment outcome was poorer for patients with group III-IV tumors (P = .01), adolescents (P = .09) and patients with alveolar or undifferentiated sarcomas (P = .12). CONCLUSION: Patients with localized tumors appear to fare better if they undergo complete abdominal wall resection (long-term survival rate, 100%) versus partial resection (long-term survival rate, 62% [P = .12]).

Abdominal Muscles↗
PubMed1999

Angiotensin converting enzyme inhibitor-induced angioedema more prevalent in transplant patients.

BACKGROUND: Angioedema in association with angiotensin converting enzyme inhibitor (ACEI) use is rare, but serious. Which patients are predisposed to the reaction and whether it involves an immune mechanism remain unclear. OBJECTIVES: To determine the frequency of ACEI angioedema in immunosuppressed cardiac and renal transplant patients. METHODS: This was a retrospective chart review of all adult cardiac (n = 156) and renal (n = 341) transplant patients followed at our hospital (years 1985 to 1995). RESULTS: Of 105 cardiac and 91 renal transplant patients on a combination of immunosuppressive and ACEI therapy, 5 (4.8%) cardiac and 1 (1%) renal patients developed angioedema. This prevalence of ACEI angioedema among cardiac and renal transplant patients is 24 times and 5 times higher, respectively, than that observed in the general population (0.1% to 0.2%). Reactions often appeared after prolonged ACEI use (average 19 months; range 3 days to 6.3 years). African-Americans were significantly more likely to experience ACEI-associated angioedema (P = .034), especially among the cardiac patients where 4 of 5 reactors were African-American. CONCLUSIONS: For unclear reasons, ACEI-induced angioedema (often late-onset) is more prevalent among immunosuppressed cardiac and renal transplant patients. Additionally, African-Americans are over-represented among those developing the reaction.

Adult↗