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Biomedical subjects

D Anderson

Publications and source records attributed to D Anderson.

At least 73 records · Page 4Linked to original sources
PubMed2001

A comparison of three rapid D-dimer methods for the diagnosis of venous thromboembolism.

We compared three rapid D-dimer methods for the diagnosis of venous thromboembolism. Patients presenting to four teaching hospitals with the possible diagnosis of deep vein thrombosis or pulmonary embolism were investigated with a combination of clinical likelihood, D-dimer (SimpliRED) and initial non-invasive testing. Patients were assigned as being positive or negative for deep vein thrombosis or pulmonary embolism based on their three-month outcome and initial test results. The three D-dimer methods compared were: (a) Accuclot D-dimer (b) IL-Test D-dimer (c) SimpliRED D-dimer. Of 993 patients, 141 had objectively confirmed deep vein thrombosis or pulmonary embolism. The sensitivity of SimpliRED, Accuclot and IL-Test were 79, 90 and 87% respectively. All three D-dimer tests gave similar negative predictive values. The SimpliRED D-dimer was found to be less sensitive than the Accuclot or IL-Test. When combined with pre-test probability all three methods are probably acceptable for use in the diagnosis of venous thromboembolism.

Fibrin Fibrinogen Degradation Products↗
PubMed2001

Prevention and management of cerebrospinal fluid fistula after transtemporal skull base surgery.

The incidence of cerebrospinal fluid (CSF) fistula after transtemporal skull base surgery can range from 4% to 19%. The risk of CSF leak may be related to tumor size and location, the extent of the dural defect, and the technical aspects of the wound reconstruction. Prevention of meningitis depends on the early detection and management of CSF leakage. Five hundred eighty-nine patients underwent a variety of transtemporal surgical approaches for the extirpation of skull base tumors at our institution from July 1988 to October 1999. The medical records were reviewed retrospectively to identify the tumor histology, size, and location, as well as the surgical approach, defect reconstruction technique, and the incidence of postoperative CSF leak. The risk of CSF fistulae was greatest in using the retrosigmoid approach (8%) and lowest in those who underwent a translabyrinthine approach (4%). Tumor size had no bearing on the incidence of the CSF leak and the overall incidence of meningitis was 1.0%. This article outlines our institutional objective for the prevention and management of CSF fistula after transtemporal skull base surgery. Illustrative cases will be presented.

Journal Article↗
PubMed2001

Cerebrospinal fluid fistula after transtemporal skull base surgery.

OBJECTIVES: The purpose of this article is to outline our methods for the prevention and management of cerebrospinal fluid (CSF) leak after transtemporal skull base surgery. METHODS: A total of 589 patients underwent a variety of transtemporal surgical approaches for the extirpation of skull base tumors at our institution from July 1988 to October 1999. The medical records were retrospectively reviewed to identify the tumor histology, size, and location as well as the surgical approach, defect reconstruction technique, and the incidence of postoperative CSF leak. RESULTS: The risk of CSF fistulae was greatest in utilizing the restrosigmoid approach (8%) and least in those who underwent a translabyrinthine approach (4%). Tumor size had no bearing on the incidence of the CSF leak and the overall incidence of meningitis was 1.0%. CONCLUSION: The proper surgical technique will minimize the risk of CSF leak after transtemporal skull base surgery. Immediate management of CSF fistulae helped prevent meningitis in the majority of these patients.

Adolescent↗
PubMed2001

Expression of ras (p21) protein in plasma from exposed workers and from patients with lung disease.

Oncogenes are involved with the regulation of cellular proliferation and thus could be important in the development of many cancers. Cells transformed in culture by ras genes can be activated either by the introduction of specific point mutations or by overexpression of the normal proto-oncogene. The ras genes encode a protein of 189 amino acids (molecular mass 21 kDa) designated as p21. ras p21 proteins are contained in all eukaryotic cells on the inner surface of the plasma membrane. We measured ras p21 proteins in lung cancer patients, patients with chronic obstructive pulmonary disease (COPD) and workers exposed to emissions from petrochemical plants and 1,3-butadiene and 1,3-butadiene/styrene. Proteins were separated by gel electrophoresis, transferred to a nitrocellulose membrane by Western blotting and detected by chemiluminescence. A monoclonal pan-ras antibody was used as the primary antibody. Optical densities of the peak area of the protein bands were calculated and values which were two standard deviations above negative control means were considered positive. Many of the cancer patients and some of the COPD patients gave positive responses, whilst exposed worker groups did not show statistically significant increases by comparison with the controls. Thus, an increase in ras oncoproteins could be a biomarker for cancer or the disease state in general, but it cannot be ruled out that it is a biomarker for exposure since many of the individuals examined were smokers exposed to cigarette smoke.

Adult↗
PubMed2001

Using standardized patients to teach end-of-life skills to clinical clerks.

BACKGROUND: This study examines the use of standardized patients to teach end-of-life skills to clinical clerks. METHODS: Forty-four third-year clinical medical students participated in a half-day standardized patient workshop that was precepted by faculty members. The students were asked to report on their perceived abilities prior to the workshop and these were compared with post-workshop responses. The students were also asked to provide an overall evaluation of the standardized patient workshop as a learning experience. RESULTS: The students uniformly found the workshop to be realistic, found the faculty facilitators to be helpful, and found the workshop effective in enhancing their end-of-life skills. Following participation in the workshop, students reported significant improvements in their perceived abilities to deal with pain, to appreciate cultural differences in the dying process, to deliver bad news, and to understand the legalities of do-not-resuscitate orders. CONCLUSIONS: Standardized patient workshops are useful for teaching end-of-life skills.

Clinical Clerkship↗
PubMed2001

A pilot investigation to subjectively measure treatment effect and side-effect profile of non-ablative skin remodeling using a 532 nm, 2 ms pulse-duration laser.

BACKGROUND AND OBJECTIVE: Carbon dioxide laser skin resurfacing has become a standard treatment for wrinkles and sun-damaged skin. This ablative treatment, however, is associated with undesirable complications and long recovery times. A growing body of evidence suggests that dermal inflammation and subsequent collagen formation can be stimulated without removal of the epidermis, raising the possibility of effective non-ablative skin remodeling for mild to moderately photodamaged skin. MATERIALS AND METHODS: This preliminary study was performed to evaluate the safety and subject satisfaction of non-ablative skin remodeling using a 532 nm, 2 ms pulse-duration, frequency-doubled Nd:YAG laser. Subjects with mild-to-deep lip wrinkles and mild-moderate acne scarring were treated one half of their lip (wrinkles) or cheek (acne scarring), leaving the other side as an untreated control. Subjects were treated at 3-6 week intervals for an average of three treatments. Subjective assessment of improvement was estimated by subject self-evaluation of the percentage improvement over baseline, and a blinded observer attempted to identify the treated side on physical examination. RESULTS: Subjective assessment revealed an average improvement of 51.4% and 53.6% for upper lip wrinkles and facial acne scarring, respectively. Side effects were limited to transient erythema that resolved over 0.25-2 hours following treatment. CONCLUSIONS: These results demonstrate that non-ablative treatment with the 532 nm, 2 ms pulse-duration Nd:YAG laser results in subjective improvement of rhytides and acne scarring, with a high safety profile.

Acne Vulgaris↗
PubMed2001

Randomized placebo controlled trial of lofexidine hydrochloride for chronic pelvic pain in women.

BACKGROUND: We hypothesised that the orally-active alpha(2)-adrenoceptor agonist lofexidine hydrochloride would ameliorate chronic pelvic pain in women. METHODS: A randomized placebo-controlled parallel group trial was undertaken in the University Hospital Gynaecology Clinic. Women with pelvic pain of at least 6 months duration were eligible, and were randomized using a sealed envelope system to receive up to 600 mg lofexidine hydrochloride twice daily over 8 weeks or placebo. Outcome measures were summary and daily diary visual analog scales for pain (VAS) and a 5 point self rating scale. RESULTS: 9/19 women randomized to lofexidine completed the study compared to 14/20 of those randomized to placebo. Intention-to-treat analysis showed that 4/19 in the lofexidine group achieved 50% or greater reduction in VAS compared with 8/20 in the placebo group (OR 2.5, 95% CI 0.6--10.3). Summary and diary VAS were closely correlated. CONCLUSIONS: Within the limits of a small study with power to detect only a substantial effect, we conclude that lofexidine hydrochloride is not effective for the treatment of chronic pelvic pain.

Acetaminophen↗
PubMed2001

Effect of hydroxyethyl starch on coagulopathy in a swine model of hemorrhagic shock resuscitation.

BACKGROUND: Hydroxyethyl starch (HES) has a known dose-dependant effect on coagulopathy. The purpose of this study was to determine the effect of HES on coagulopathy after a period of hemorrhagic shock. METHODS: Anesthetized swine underwent a 15-minute, 40% blood volume hemorrhage (28 mL/kg) and a 1-hour shock period, followed by resuscitation with sham resuscitation (group I); 6% HES, 15 mL/kg (group II); 5% albumin, 15 mL/kg (group III); lactated Ringer's solution, 39 mL/kg, and 6% HES, 15 mL/kg (group IV); and lactated Ringer's solution, 39 mL/kg, and 5% albumin, 15 mL/kg (group V). Coagulation function was measured by bleeding time, prothrombin time, partial thromboplastin time, fibrinogen, platelet count, and thromboelastography. RESULTS: Platelet counts decreased significantly (p < 0.05) in all resuscitation groups except the sham resuscitation group. A significant decrease in platelets, fibrinogen levels, and maximum amplitude on thromboelastography was related to a dilutional effect of the fluid given and not a result of HES at the dose tested. CONCLUSION: The linear dose-related coagulopathic effects of HES when given at moderate doses does not seem to be worsened by prolonged periods of hemorrhagic shock. The coagulopathy seen during resuscitation from hemorrhagic shock seems to be a dilutional effect.

Analysis of Variance↗
PubMed2001

The impact of a worksite health promotion program on short-term disability usage.

This study examined the impact of a worksite health promotion program on short-term disability (STD) days in a large telecommunications company. The evaluation used a quasi-experimental, multiple time-series design with between-group comparison of workdays lost due to STD to determine impact. The study period was 3 years and included 1628 employees on STD leave. Self-selected program participants were compared with non-participants on net days lost at three assessment points: the year before the launch of the program, and each of 2 years post-launch. A comprehensive health promotion program was developed to reduce health care costs, improve employee satisfaction, and enhance the employer's image. Key features of the program included reimbursement for employees participating in the Health Risk Assessment and in wellness or fitness activities. Other features included occupational health services, targeted interventions for high-risk employees, self-care materials, and a nurse advice line. Results revealed no significant differences at baseline between participants and non-participants for net days lost while on STD leave. At the post-program launch, non-participants' net days lost significantly increased from 33.2 to 38.1 when controlled for age, gender, job type, tenure, and STD category, whereas the participant group average net days lost decreased from 29.2 to 27.8. After adjusting for baseline differences, we found a 6-day difference between groups, which represented a 20% program impact. This study found that participation in a health promotion reimbursement program had a significant impact on average net days lost for employee STD absence. These findings represented potential savings in excess of $1,371,600 over a 2-year period. Future program evaluation efforts will address the impact on medical care costs related to program participation.

Absenteeism↗
PubMed2001

Characterization of a maternal-fetal HIV transmission model using pregnant macaques infected with HIV-2(287).

To study mechanisms involved in mother-to-fetus transmission of human immunodeficiency virus (HIV) in utero, we have developed a chronically catheterized pregnant macaque model that permits simultaneous and sequential determination of virus in maternal and fetal blood and amniotic fluid during pregnancy. In this report, we have characterized this model using three groups of pregnant macaques designed to sample: (1) maternal blood, fetal blood, and amniotic fluid (n = 6); (2) maternal blood and amniotic fluid (n = 6); or (3) maternal blood only (n = 2). After inoculation with the highly pathogenic HIV-2(287), all pregnant macaques developed brief but intense viremias followed by precipitous CD4+ T-cell declines within 2-3 weeks. While all the infants born to dams of the three groups were HIV positive, the degree of infection and outcome of HIV infection varied. All infants were shown to be HIV-RNA-positive by reverse transcriptase-polymerase chain reaction (RT-PCR). However, HIV-infected cells were detected only in the blood of those born to dams enrolled in groups 1 and 2: most of these infants progressed to CD4+ T-cell depletion. The infants in group 3 exhibited HIV-RNA in plasma, although neither HIV-infected cells nor CD4+ T-cell depletion was detectable. However, all infants developed HIV-2-specific antibody at various levels by 2 months of age. Together, the data suggest that, while the degree of instrumentation may modulate intensity of virus transmission to fetus, the highly pathogenic HIV-2(287) exhibited a high frequency of virus transmission from the mother to fetus.

Amniotic Fluid↗
PubMed2001

Outcome of staged reconstructive surgery for hypoplastic left heart syndrome following antenatal diagnosis.

BACKGROUND AND AIMS: Staged reconstructive surgery has radically altered the prognosis of hypoplastic left heart syndrome (HLHS). Antenatal diagnosis allows for appropriate counselling, and time to consider treatment options. We report outcome from a centre where most cases are antenatally diagnosed and delivered on site. METHODS: Information was collated on 188 consecutive cases of HLHS between 1995 and 2000, including timing of diagnosis, outcome of pregnancy, and age and outcome at each stage of surgery. At Guy's Hospital, 174 cases were diagnosed antenatally, of whom 50 underwent surgery. Fourteen others (five diagnosed antenatally at other centres, and nine diagnosed postnatally) also underwent surgery. RESULTS: Survival after stage I (the Norwood operation) was 52% (33/64). Postoperative survival after stage II (the hemi-Fontan operation, performed in 29), and stage III (the Fontan operation, performed in 10), was 100%. Two late deaths occurred 3 and 10 months after stage II, giving overall survival of 48% (31/64). At follow up, three children have neurological impairment, and one had poor right ventricular function necessitating cardiac transplantation. CONCLUSIONS: Antenatal diagnosis allows informed decisions about treatment options, and facilitates preoperative care. Mortality following stage I is high, irrespective of timing of diagnosis, but medium term outcome for survivors is good.

Cardiac Surgical Procedures↗
PubMed2001

Memory for symptoms in COPD patients: how accurate are their reports?

The purpose of this study was to examine the accuracy of self-reports of symptom intensity in patients with chronic obstructive pulmonary disease (COPD) and factors that might influence recall of that intensity. Thirty COPD (forced expiratory volume in one second (FEV1) 36 +/- 17% predicted) subjects recorded their dyspnoea and fatigue intensity scores on a 0-10 scale for 14 consecutive days. On the fourteenth day, subjects recalled their average, greatest and least symptom intensity for the previous 14 days. General cognitive function, spirometry, and oxygenation were also measured. No significant differences were found between actual and recalled scores for dyspnoea or fatigue. General cognitive function, measured by the Mini Mental State Exam, correlated with the greatest and least dyspnoea and average fatigue difference scores (recall-actual) and contributed to the variance in the average and least dyspnoea recalled scores. The greatest contributor to the variance in the recall scores of both symptoms was the symptom intensity level on the day of recall. These results highlight the importance of current levels of symptom intensity and cognitive function when appraising symptoms in chronic obstructive pulmonary disease patients.

Aged↗
PubMed2001

Prevalence of mental retardation and developmental disabilities: estimates from the 1994/1995 national health interview survey disability supplements.

In 1994 and 1995, the National Health Interview Survey included a Disability Supplement (NHIS-D) to collect extensive information about disabilities among individuals sampled as part of annual census-based household interview surveys. Here we describe the development and application of operational definitions of mental retardation and developmental disabilities to items in the NHIS-D to estimate prevalence. In our analyses, we estimate the prevalence of mental retardation in the noninstitutionalized population of the United States to be 7.8 people per thousand (.78%); of developmental disabilities, 11.3 people per thousand (1.13%); and the combined prevalence of mental retardation and/or developmental disabilities to be 14.9 per thousand (1.49%). Differences in prevalence estimates for mental retardation and developmental disabilities and among people of various ages are explored.

Journal Article↗
PubMed2001

Evaluation and survey of intravenous vitamin K1 for treatment of coagulopathy in critically ill patients.

STUDY OBJECTIVES: To determine patient factors associated with coagulopathy, to assess variables affecting response to vitamin K1, to describe vitamin K1-associated adverse reactions, and to survey Canadian tertiary care hospitals about vitamin K1 practice patterns in their intensive care units (ICUs). DESIGN: Retrospective chart audit and prospective survey. SETTING: Medical-surgical ICU with a 23-bed complement in a tertiary care, university-affiliated hospital, and 47 Canadian tertiary care hospitals. PATIENTS: Forty-eight critically ill patients with nonconsumptive coagulopathies. INTERVENTION: Intravenous vitamin K1 utilization over 4 months. MEASUREMENTS AND MAIN RESULTS: The only independent risk factor for elevated baseline international normalized ratios (INRs) was Acute Physiologic and Chronic Health Evaluation (APACHE) II score (r2 = 0.51, p<0.05). The INR values decreased after two doses of vitamin K1 10 mg for patients grouped as a whole (2.14 +/- 0.96 to 1.61 +/- 0.62, p<0.0001) and when patients were stratified according to APACHE II scores below 23 (1.83 +/- 0.44 to 1.34 +/- 0.18, p<0.05). The INRs were not significantly reduced for patients with APACHE II scores of 23 or greater (2.44 +/- 1.23 to 1.82 +/- 0.66). No variables were associated with response, and adverse events were not observed. Of 47 Canadian tertiary care hospitals surveyed, 27 (55%) responded. Twenty-four (89%) indicated that vitamin K1 was administered intravenously, and no adverse events resembling anaphylaxis were reported. CONCLUSION: Administration of two doses of intravenous vitamin K1 10 mg was associated with reversal of coagulopathies, but variable responses may be expected for patients with high APACHE II scores. Randomized, placebo-controlled studies are necessary to confirm the effectiveness of vitamin K1.

APACHE↗
PubMed2001

Effect of antioxidant flavonoids and a food mutagen on lymphocytes of a thalassemia patient without chelation therapy in the Comet assay.

Thalassemia remains a significant health problem in Europe, the Middle East, and Asia. In such patients, generally high iron levels make free oxygen radicals accessible, for example, through Fenton-type chemistry, and generate superoxide and hydroxyl radicals. Increased oxygen radical capacity is known to be associated with cancer and ageing. It was shown in previous studies that peripheral blood lymphocytes from a sickle/beta thal double heterozygote-sickle phenotype, thalassemia patient, not yet on chelation therapy, were more sensitive to the effects of oxygen radicals and iron salts than lymphocytes from normal controls. Iron overload in thalassemia patients can result from dietary absorption. It was considered that with other dietary agents, such as food mutagens and flavonoids, the thalassemia patient might also show increased sensitivity to the effects of these agents. The present study, therefore, compared the effects of the food mutagen/carcinogen, 3-amino-1-methyl-5H-pyrido(4,3-b)indole (Trp-P-2), in fresh or frozen normal human peripheral lymphocytes with frozen lymphocytes from the same thalassemia patient. The lymphocytes from the thalassemia patient showed an approximately two-fold increase in sensitivity. When a combination of Tryp-P-2, with either quercitin or kaempferol, was compared in frozen lymphocytes and lymphocytes from the thalassemia patient, a two-fold increase in sensitivity was also maintained. Responses to Trp-P-2 were reduced to untreated control levels at the highest doses of quercitin and kaempferol, and were highly significantly different by comparison with Trp-P-2 alone (P<0.001). The flavonoids acted in an antigenotoxic/antioxidant manner. Sensitivity was slightly increased with kaempferol by comparison with quercitin. At low concentrations of the flavonoids there was some evidence of an exacerbation of response, perhaps due to a switch to pro-oxidant status. This exacerbation of response at low doses of flavonoids has been seen in earlier studies with normal lymphocytes. Teratogenesis Carcinog. Mutagen. 21:165-174, 2001.

Carbolines↗