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Biomedical subjects

L Nelson

Publications and source records attributed to L Nelson.

At least 19 recordsLinked to original sources
PubMed2003

The interpretation of symptoms of severe dietary restraint.

A recent cognitive-behavioural theory of eating disorders proposes that people with eating disorders interpret symptoms of dietary restraint in terms of control. The primary aim of the present study was to test this hypothesis. A second aim was to test the hypothesis derived from clinical observation that people with eating disorders view these symptoms positively. Forty-four participants meeting DSM-IV criteria for a clinical eating disorder and 80 control participants with no history of an eating disorder completed an ambiguous scenario paradigm and self-report measures of eating disorder features and depression. Patients with eating disorders were significantly more likely to interpret symptoms of dietary control in terms of control, providing support for the cognitive-behavioural theory. There was only partial support for the second hypothesis. The implications for the new cognitive-behavioural theory and therapy are discussed.

Adult↗
PubMed2001

Photochemical and pharmacological evaluation of 7-nitroindolinyl-and 4-methoxy-7-nitroindolinyl-amino acids as novel, fast caged neurotransmitters.

Reagents capable of rapid and efficient release of neuroactive amino acids (L-glutamate, GABA and glycine) upon flash photolysis of thermally stable, inert precursors have been elusive. 7-Nitroindolinyl (NI)-caged and 4-methoxy-7-nitroindolinyl (MNI)-caged compounds that fulfil these criteria are evaluated here. These caged precursors are highly resistant to hydrolysis. Photolysis is fast (half time< or =0.26 ms) and the conversion achieved with a xenon flashlamp is about 15% for the NI-caged L-glutamate and about 35% for the MNI-caged L-glutamate. A procedure is described for calibration of photolysis in a microscope-based experimental apparatus. NI-caged L-glutamate itself showed no agonist or antagonist effects on AMPA and NMDA receptors in cultured neurones, and had no effect on climbing fibre activation of Purkinje neurones. A control compound with identical photochemistry that generated an inert phosphate upon photolysis was used to confirm that the intermediates and by-products of photolysis have no deleterious effects. MNI-caged L-glutamate is as stable and fast as NI-caged L-glutamate and similarly inert at glutamate receptors, but about 2.5 times more efficient. However, NI-caged GABA is an antagonist at GABA(A) receptors and NI-glycine an antagonist at glycine receptors. The results show the utility and limitations of these fast and stable caged neurotransmitters in the investigation of synaptic processes.

Animals↗
PubMed2001

Correlation of impedance minute ventilation with measured minute ventilation in a rate responsive pacemaker.

Although rate responsive pacing based on impedance minute ventilation (IMV) is now standard, there is almost no data confirming the relationship between IMV from an implanted pacemaker and measured minute ventilation (VE) during exercise. Nineteen completely paced adults implanted with Medtronic Kappa 400 pacemakers underwent symptom-limited maximal metabolic treadmill testing using a modified Minnesota Pacemaker Response Protocol. Minute ventilation (VE, L/min) was simultaneously measured using the flowmeter of a respiratory metabolic gas analysis system and the transthoracic impedance minute ventilation circuitry of the pacemaker. Correlation coefficients (r) were used to find the best fit line to describe the relationship between the two measurements. Mean (+/- SD) r values for the first, second, and third order polynomial equations and for log and exponential equations were: 0.92 +/- 0.08, 0.94 +/- 0.04, 0.95 +/- 0.04, 0.91 +/- 0.06, and 0.91 +/- 0.07, respectively. None of the r values were statistically different from the first order equation. Transthoracic IMV as measured by the Medtronic Kappa 400 is closely correlated to measured minute ventilation and is represented well by a first order (linear) equation.

Adult↗
PubMed2001

Is surgical decontamination definitive treatment of "body-packers"?

The current recommendations for body-packers are based on packet content, the presence of drug toxicity, or of bowel obstruction. Asymptomatic patients are usually treated with activated charcoal and whole bowel irrigation (WBI). Surgical removal of packets is advocated in symptomatic cocaine body-packers and in those with bowel obstruction. Currently, surgery is regarded as definitive. However, we report 2 body-packers who show the limitations of this technique. These cases show the importance of confirming the absence of drug packets in the gastrointestinal (GI) tract as the definitive end-point in the treatment of body-packers.

Adult↗
PubMed2001

A multi-institutional study of radiofrequency volumetric tissue reduction for OSAS.

OBJECTIVES: Radiofrequency volume reduction (RFTVR) is a minor procedure directed at reducing the tongue base volume to treat obstructive sleep apnea. Subjective and objective treatment effectiveness was evaluated. STUDY DESIGN AND SETTING: Two separate prospective, matched, nonrandomized, open enrollment treatment groups (RFTVR, n = 73 and nasal continuous positive airway pressure (CPAP, n = 99) were concurrently enrolled in a multicenter study. RESULTS: Fifty-six (76.7%) RFTVR completed PSG with a mean 5.4 +/- 1.8 treatments (13,394 +/- 5459 joules). Perioperatively, acute pain was mild to moderate; edema, mucosal erosion, paresthesia, tinnitus were infrequent; and speech, swallowing taste, or throat irritation were unchanged. Self-reported outcomes did not differ between RFTVR and CPAP groups. Mean apnea/hypopnea index decreased (40.5 +/- 21.5 to 32.8 +/- 22.6 events/hr, P < 0.01). Electrolyte solution injected predicted results (r = 0.43, P < 0.001). The most severe complication was abscess (1.1%). CONCLUSION: RFTVR improves apnea/hypopnea index. Improvement may be related to solution injected with treatment. RFTVR and CPAP clinical outcomes improvement were similar. CLINICAL SIGNIFICANCE: In mild obstructive sleep apnea, treatment of symptomatic outcomes with RFTVR may be an alternative to CPAP.

Adult↗
PubMed2001

Temperature-controlled radiofrequency tissue volume reduction in the human soft palate.

OBJECTIVE: To validate the use of temperature-controlled radiofrequency energy applied to the soft palate in a multicenter setting for reduction of snoring in a minimally morbid manner. METHODS: Prospective, nonrandomized multicenter study of 113 patients who had a respiratory disturbance index less than 15 and minimum oxygen saturation not less than 85% and who were seeking treatment for habitual disruptive snoring. Patients were given either single or multiple lesions to the soft palate during each treatment session. RESULTS: Patients received 1978 J on average with an overall average of 2.4 treatments. Snoring scores went from an average of 7.8 (visual analog scale (VAS), 0-10) pretreatment to 3.2 posttreatment. Pain was minimal, averaging 1.7 (VAS 0-10) on days 1 to 6. Complications were few and transient, and mild. CONCLUSIONS: The multiple lesion protocol was the most successful; reducing snoring from 7.6 to 2.7, on a VAS with an average of 1232 J delivered over 1.6 treatments. Temperature-controlled radiofrequency was found to be a minimally invasive, well-tolerated procedure that was safe and efficacious in this study group.

Adult↗
PubMed2001

Rational use of toxicology testing in children.

The majority of all patients with poison exposures in the United States are children. The evaluation and management of poisoned patients may be aided by the use of laboratory assays, ranging from basic assessments not uniquely indicated for the poisoned patient to highly sophisticated laboratory tests with very specific indications. Literature concerning poisoning in pregnant patients is evaluated and recommendations regarding the utility of pregnancy testing in poisoned females are discussed. Recent studies evaluating the use of toxicology testing in pediatrics have concluded that the use of comprehensive toxicology screening in pediatric patients is costly and does not affect the medical management of most poisoned patients. The utility of focused quantitative serum assays to determine serum levels of particular poisons is reviewed. Toxicology tests used for detection of drugs of abuse, with a particular focus on the capabilities and limitations of such tests, are discussed. The potential pitfalls that occur when toxicology tests are obtained indiscriminately, are misapplied, or are misunderstood are analyzed. Hair sampling as nonemergent toxicology testing for drugs of abuse is discussed.

Child↗
PubMed2000

Clinical manifestations in a large hereditary hemorrhagic telangiectasia (HHT) type 2 kindred.

HHT type 2 (HHT 2) is a multi-system vascular dysplasia caused by a mutation in the ALK-1 gene, but the phenotype has not been well defined. We report on 51 members of an HHT 2 kindred with an ALK-1 gene mutation shown to be associated with the disorder. This ALK-1 mutation was detected in 38 kindred members who were evaluated systematically for associated vascular abnormalities. Pulmonary arteriovenous malformations (AVMs) were found in 6% of those screened, cerebral AVM in 7%, hepatic AVM in 17%, and spinal AVM in 3%. We discuss these and other findings in the 38 affected kindred members, as well as findings in the 13 kindred members in whom the mutation was not detected. This study shows that pulmonary, cerebral, spinal, and hepatic AVMs can all occur in HHT 2. It also adds to the evidence suggesting that pulmonary AVMs are more common in HHT 1 than in HHT 2. We identify a higher prevalence of hepatic AVMs than previously reported in either HHT 1 or 2. This may be specific to the mutation in this kindred, but probably reflects the lack of routine screening for this manifestation. Even in this family in which all affected individuals have the same mutation, the clinical manifestations of HHT and their severity varied tremendously. Intrafamilial variation in expression of HHT is clearly significant, emphasizing the difficulty in establishing the diagnosis in individuals and in sub-typing families when DNA testing is not available.

Adolescent↗
PubMed2000

Herbal and alternative medicine.

An extensive range of herbal and dietary supplements is now available, and use of these products by ED patients is fairly common. Emergency physicians should be familiar with some of the products used more frequently for common complaints. Emergency personnel also should be vigilant for toxic syndromes resulting from ingestion of certain of these products and be wary of possible toxicity from any of these supplements owing to their minimal quality control and absence of FDA regulation.

Antioxidants↗
PubMed2000

Influence of posture, breathing pattern, and type of exercise on minute ventilation estimation by a pacemaker transthoracic impedance sensor.

Previous studies have shown a high correlation between transthoracic impedance minute ventilation (IMV) determined by a pacemaker sensor and actual minute ventilation (VE) measured by standard methods. We hypothesized that several factors (e.g., posture, breathing pattern, and exercise type) could potentially affect the calibration between IMV and VE. In patients with Medtronic Kappa 400 pacemakers, VE (L/min) was monitored using a standard cardiopulmonary metabolic gas analysis system with simultaneous recording of IMV (ohms/min) using DR-180 extended telemetry monitors. Effects of posture and of breathing pattern at rest (19 patients; age 60 +/- 13 years) were evaluated by monitoring each patient under three conditions: (a) slow breathing, supine, (b) slow breathing, sitting, and (c) shallow breathing, supine. Calibration at rest was defined as the ratio of IMV to VE. Effect of type of exercise on calibration compared treadmill versus graded bicycle ergometer exercise (18 patients; age 62 +/- 14 years). Calibration during exercise was defined as: (a) "Begin" (the IMV to VE ratio at VE = 10 L/min, the typical VE value at beginning of exercise), and (b) slope of the IMV/VE regression line. Calibration of IMV/VE was significantly smaller for sitting versus supine position (0.7130.177, P < 0.001) and for shallow versus slow breathing (0.7210.373, P < 0.001), and larger for treadmill versus bicycle exercise (Begin: 1.240.43, P = 0.018; Slope: 1.260.42, P = 0.013). In conclusion, posture, breathing pattern, and type of exercise affect the IMV estimation of the actual VE, possibly by altering the static or dynamic geometry (thus, the impedance) of the intrathoracic viscera.

Arrhythmias, Cardiac↗
PubMed2000

Surgical drainage devices. Improved securement = improved outcomes.

The use of securement devices to prevent the risks, discomfort and expense of accidental dislodgment of surgical drains was investigated by the Royal Columbian Hospital after nursing staff began reporting a previously unrecognized post-operative pain syndrome. Nursing staff discovered the cause and eliminated the recurring syndrome by taking two preventative measures: securing urinary catheters with a Statlock securement device, and hanging the catheter bags to the OR stable. Both practice changes eliminated traction on the catheter, preventing its migration into the patient's bladder neck that caused the syndrome's symptoms of bladder pain and spasm when the patient woke up. There were modifications to the chest tube securement protocol that also included a Statlock securement device that improved the skin integrity of patients and increased nursing application efficiencies by 100%.

Bandages↗
PubMed1999

Ingested interferon alpha induces Mx mRNA.

We have demonstrated that ingested murine interferon alpha (IFN-alpha) suppressed clinical relapse in chronic relapsing experimental autoimmune encephalomyelitis (CR-EAE), decreased inflammation and suppressed the adoptive transfer of EAE, and is a biological response modifier in patients with multiple sclerosis. We examined the relative levels of the Mx mRNA signal using semiquantitative reverse transcription-polymerase chain reaction analysis on splenocytes from mice and peripheral blood mononuclear cells from man after IFN-alpha ingestion. Both mice and man demonstrated inducible levels of Mx mRNA after ingesting IFN-alpha. Murine spleen T cells and CD8(+)T cells also demonstrated upregulation of Mx mRNA. Murine whole splenocytes demonstrated upregulation of Mx mRNA after IFN-alpha ingestion of 10 and 100 U, but not after 0, 1000, 5000 U. Ingested IFN-alpha acts via established pathways of type 1 IFN signalling.

Administration, Oral↗
PubMed1999

Ovarian cancer in young women in Sweden, 1989-1991.

The present study is an evaluation of the symptoms and gynecological status, at the time of seeking medical advice, among women of reproductive age diagnosed with ovarian malignancies. The study was based on the medical records of all women in Sweden between 15 and 40 years of age who were diagnosed with ovarian malignancies during a 3-year period (1989-1991). The study focused on the diagnosis and panorama of symptoms. These data were compared to the records of more than 10,000 women in this age group during the same period of time who underwent surgery for ovarian changes that resulted in benign diagnoses. The 152 cases of ovarian cancer included only 1 patient who was without symptoms, had normal pelvic status upon manual examination, and a sonographically diagnosed simple cyst. These data support the conclusion that the majority of young women with ovarian cancer have symptoms and/or clinically detectable adnexal masses at the time when medical advice is sought. These studies suggest that diagnosis of ovarian cancer is unlikely in young healthy women lacking subjective symptoms and an adnexal mass upon pelvic examination. In conclusion, programs for the management of simple cysts and development of noninvasive diagnostic methods for ovarian changes found in patients in the reproductive age group are needed in order to reduce the number of patients subjected to operative intervention.

Adolescent↗
PubMed1999

Liposomal prostaglandin E1 (TLC C-53) in acute respiratory distress syndrome: a controlled, randomized, double-blind, multicenter clinical trial. TLC C-53 ARDS Study Group.

OBJECTIVE: To evaluate the safety and efficacy of an intravenous liposomal dispersion of prostaglandin E1 as TLC C-53 in the treatment of patients with acute respiratory distress syndrome (ARDS). DESIGN: Randomized, prospective, multicenter, double-blind, placebo-controlled, phase III clinical trial. SETTING: Forty-seven community and university-affiliated hospitals in the United States. PATIENTS: A total of 350 patients with ARDS were enrolled in this clinical trial. INTERVENTION: Patients were prospectively randomized in a 1:1 ratio to receive either liposomal prostaglandin E1 or placebo. The study drug was infused intravenously for 60 mins every 6 hrs for 7 days starting with a dosage of 0.15 microg/kg/hr. The dose was increased every 12 hrs until the maximal dose (3.6 microg/kg/hr) was attained or intolerance to further increases developed. Patients received standard aggressive medical/surgical care during the infusion period. OUTCOME MEASURES: The primary outcome measure was the time it took to wean the patient from the ventilator. Secondary end points included time to improvement of the PaO2/FIO2 ratio (defined as first PaO2/FIO2 > 300 mm Hg), day 28 mortality, ventilator dependence at day 8, changes in PaO2/FIO2, incidence of and time to development/resolution of organ failure other than ARDS. RESULTS: A total of 348 patients could be evaluated for efficacy. The distribution of variables at baseline describing gender, lung injury scores, Acute Physiology and Chronic Health Evaluation II scores, PaO2/FIO2, pulmonary compliance, and time from onset of ARDS or from institution of mechanical ventilation to the first dose of study drug was similar among patients in the liposomal prostaglandin E1 (n = 177) and the placebo (n = 171) treatment arms. There was no significant difference in the number of days to the discontinuation of ventilation in the liposomal prostaglandin E1 group compared with the placebo group (median number of days to off mechanical ventilation, 16.9 in patients receiving liposomal prostaglandin E1 and 19.6 in those administered placebo; p = .94). Similarly, mortality at day 28 was not significantly different in the two groups (day 28 mortality, 57 of 176 (32%) in the liposomal prostaglandin E1 group and 50 of 170 (29%) in patients receiving placebo; p = .55). In contrast, treatment with liposomal prostaglandin E1 was associated with a significantly shorter time to reach a PaO2/FIO2 ratio of >300 mm Hg (median number of days to reaching a PaO2/FIO2 ratio >300 mm Hg: 9.8 days in the liposomal prostaglandin E1 group and 13.7 days in patients receiving the placebo; p = .02). Among the subgroups examined, time to off mechanical ventilation was significantly reduced in patients who received at least 85% of a full dose (i.e., > 45.9 microg/kg) of liposomal prostaglandin E1 (median number of days to discontinuation of ventilation, 10.3 in the liposomal prostaglandin E1 group and 16.3 days in patients receiving placebo; p = .05). The overall incidence of serious adverse events was not significantly different in the liposomal prostaglandin E1 (40%) or placebo-treated (37%) groups. Drug-related adverse events of all kinds were reported in 69% of the patients receiving liposomal prostaglandin E1 compared with 33% of the placebo group, with hypotension and hypoxia (occurring in 52% and 24% of the liposomal prostaglandin E1-treated patients, respectively, and 17% and 5% of the placebo-treated patients, respectively) being noted most frequently. CONCLUSIONS: In the intent-to-treat population of patients with ARDS, treatment with liposomal prostaglandin E1 accelerated improvement in indexes of oxygenation but did not decrease the duration of mechanical ventilation and did not improve day 28 survival.

Adult↗