PubMed Health⌕ Search

Biomedical subjects

Paul Walker

Publications and source records attributed to Paul Walker.

At least 19 recordsLinked to original sources
PubMed2006

Acoustic parameters of snoring sound to assess the effectiveness of sleep nasendoscopy in predicting surgical outcome.

OBJECTIVE: To assess the effectiveness of two grading systems used to predict surgical outcome in nonapneic snorers. STUDY DESIGN: A prospective observational study. Prior to undergoing palatal surgery, 20 patients completed a sleep nasendoscopic examination involving sequential steady-state sedation with intravenous propofol. Using a combination of acoustic parameters of snoring sound as an objective outcome measurement, and the answers to a specifically designed questionnaire as a subjective outcome measurement, the effectiveness of each grading system in predicting surgical outcome was examined. RESULTS: Depending on the outcome measurement used, sensitivity in predicting success of surgery for snoring varied from 16.7% to 50.0% and specificity from 38.5% to 62.5% for the Pringle and Croft system, while sensitivity varied from 91.7% to 100% and specificity from 30.8% to 31.5% for the Camilleri system. CONCLUSION: Sleep nasendoscopy using these classifications cannot be recommended as a reliable predictor of surgical outcome in nonapneic snorers. EBM RATING: C-4.

Acoustics↗
PubMed2005

Management of antenatally detected fetal airway obstruction.

Five cases of antenatally diagnosed fetal airway obstruction have been cared for at the John Hunter Children's Hospital, Newcastle, Australia. A multidisciplinary team manages them during the perinatal period. We present our technique at the time of delivery, which aims to afford us the greatest flexibility in managing both the mother, her child's airway, and the underlying lesion. We begin with an ex utero intrapartum technique (EXIT) and favor routine rigid bronchoscopy to secure the neonate's airway without preliminary attempts at endotracheal intubation.

Adult↗
PubMed2005

Comparison of a static gravity screen-roll press combination separator to a PAM-assisted gravity belt thickener system for swine waste slurry solids separation.

Liquid effluent resulting from solids separation from raw swine slurry (RS) using a static gravity screen-roll press separator (SE) and a polyacrylamide (PAM) flocculant-assisted gravity belt thickener system (BE1 and 2, with BE2 designating an added belt thickening of SE) were compared. Effluent pH was 7.6-7.7. Dissolved oxygen was less than 0.01 mg/l in RS and SE and 0.50 mg/l in BE1 and 2. Solids dry weight and total phosphorus concentrations were reduced significantly (p0.05) in SE (17-27%) and in BE1 and 2 (92-96%), relative to RS. Phosphorus concentration reductions were higher than those previously found. Settleable and suspended solids, total nitrogen and chemical oxygen demand were significantly reduced in BE1 and 2 (63-99%). No significant differences (p>0.05) were found between BE1 and 2. Results indicated that the gravity belt thickener system was more efficient at solids separation than the screen-roll press system.

Acrylic Resins↗
PubMed2005

Subcutaneous administration of cefepime.

Management of symptomatic infections can aid in palliation. We investigated the pharmacokinetics and tolerability of cefepime given as a subcutaneous infusion. This novel route of administration is proposed as an alternative to intravenous and intramuscular administration for patients treated outside an institutional setting, such as home hospice. Ten healthy adult volunteers received a single dose of 1g cefepime infused subcutaneously over 30 minutes. Serial serum samples (0.5, 1, 1.5, 2, 4, 6, 9, and 12 hours) were obtained after the end of infusion, and cefepime concentrations were determined by high performance liquid chromatography (HPLC). All serum concentration profiles were modeled by a population pharmacokinetic analysis using the Non-Parametric Adaptive Grid (NPAG) program. Acceptability of administration was evaluated using subjective sensation grading, observation of the subcutaneous site, and a final global evaluation. The mean (median) Cmax, beta-t1/2, AUC0-oo and total clearance were found to be 36.1 (30.9) mg/L, 2.34 (2.56) hours, 134.8 (125.3) h*mg/L, and 7.42 (7.98) L/h, respectively. All infusions were completed without difficulty or discomfort. No drug side effects occurred. The global acceptability was "strongly agreeable" with all the subjects. Subcutaneous infusion of cefepime appeared to result in a pharmacokinetic profile similar to that of an intramuscular injection. Our evaluations showed excellent tolerability and acceptability. These favorable results warrant further clinical evaluation.

Adult↗
PubMed2005

Administration of high-dose continuous infusion interleukin-2 to patients age 70 or over.

High-dose bolus or continuous infusion interleukin-2-based therapy can cause capillary leak syndrome. Significant cardiovascular/hemodynamic events, including myocardial infarction, hypotension, pulmonary edema, and cardiac arrhythmia, have been described with such therapy. Concern over the toxicity of highdose interleukin-2 (IL-2) therapy has led to some clinicians excluding patients 70 years of age or over. We have treated 15 patients 70 years of age or over having an Eastern Conference Oncology Group (ECOG) performance status of 0 or 1, with therapy based on continuous infusion IL-2 18 MIU/sq m/24 hours for 72 hours. All patients underwent a pretreatment evaluation of cardiac status with a low-level stress or adenosine stress test. Cycles were typically repeated every 3 weeks for 4 cycles, then every 3-4 weeks thereafter. Patients were treated by oncology nurses in either the stem cell transplant (intermediate unit) or the oncology inpatient unit. Patient characteristics were: median age, 72 years (range, 70-83 years); tumor types: melanoma (10), kidney cancer (5); most common sites of disease: lung (11), lymph nodes (6), subcutaneous (3), liver (2); prior therapy included: none (8), outpatient IL-2 (5), other immunotherapy (4). Median number of cycles received: 3 (1-10). Most common toxicities were: fever, rigors, nausea, emesis, hypophosphatemia, and hypomagnesemia. Three patients required the use of dopamine for blood pressure support. Two patients declined further therapy. There were no treatment-related deaths. No patients required endotracheal intubation or transfer to an intensive care unit. One complete and 8 partial responses (60% response rate) have been seen. Responding sites include the lung, lymph node, intact kidney primary, and liver. Median survival has not been reached at over 14 months (range 3+-26+ months). Patients who are 70 years of age and older with an ECOG performance status of 0 or 1 are able to tolerate high-dose continuous infusion IL-2-based therapy and may respond to such treatment.

Adenosine↗
PubMed2005

Correlation between development of pulmonary edema and response of pulmonary metastases of metastatic melanoma and kidney cancer to high-dose continuous-infusion interleukin-2.

The administration of high-dose continuous intravenous infusion interleukin-2 (IL-2) is able to induce the presence of lymphokine-activated killer (LAK) cells. LAK are able to nonspecifically lyse tumor cells. They are also able to lyse endothelial cells, which accounts for, at least in part, the capillary leak syndrome seen as one of the toxicities with this therapy. A pulmonary manifestation of capillary leak syndrome is the presence of pulmonary edema. We postulated that capillary leak may also be a mechanism by which LAK could conceivably reach pulmonary metastases or could be a reflection of damage of endothelial cells in vasculature supplying metastases and that capillary leak syndrome may actually correlate with the response of pulmonary metastases. We examined our database of patients with lung metastases treated with high-dose continuous infusion IL-2 (18 MIU/m(2)/day for 3 days) regimens. Eighteen patients had the following characteristics: melanoma (11), renal cancer (7), median age of 67 years (range, 28-79 years), and males (15). All patients were treated by oncology nurses on either the stem cell transplant unit or oncology ward. Pulmonary edema was defined as the presence of pleural fluid on a chest X-ray, computed tomography (CT) scan, and/or as noted on a physical examination by at least 2 observers. No patients required endotracheal intubation, mechanical ventilation, or an intensive care unit transfer. The median number of cycles received was 6 (range, 1-13). All 8 responding patients (6 patients with melanoma, 2 patients with kidney cancer) manifested pulmonary edema during interleukin-2 therapy. Four patients with pulmonary edema were nonresponders. The presence of pulmonary edema correlated with the response to therapy (p = 0.01). The median duration of response of pulmonary nodules was 5 months (range, 1-16 months). There is a correlation between the development of pulmonary edema and the response of pulmonary metastases in patients with melanoma and kidney cancer treated with high-dose continuous infusion interleukin-2.

Adult↗
PubMed2005

Palliative pain management: when both pain and suffering hurt.

Patients with advanced cancer frequently experience intractable pain without sufficient response to a conventional pharmacological approach. One reason for refractory pain at the end of life can be the bidirectional nature of pain and suffering. Three terminally ill patients were assessed using a multidimensional palliative pain concept, including sensory, affective, cognitive, and existential components. In these patients, resistant pain did not equal insufficient eradication of the nociceptive input, but also suffering. Unrelieved emotions, depressive or anxious symptoms, delirium, difficulties communicating, or chemical coping influenced the expression of pain, illuminating the phenomenon of somatization. Palliative pain treatment integrated analgesic treatments, psychological, rehabilitative, and existential interventions, in consideration of individual expectations and outcomes. With the disciplined assessment and alternative multidisciplinary palliative approach, the quality of life of three terminally ill cancer patients with intractable pain could be enhanced, and unnecessary interventions and escalation of medications avoided.

Adult↗
PubMed2004

Bioavailability of silver and its relationship to ionoregulation and silver speciation across a range of salinities in the gulf toadfish (Opsanus beta).

Silver is taken up as a Na(+) analog (Ag(+)) by freshwater organisms, but little is known about its bioavailability in relation to salinity. Adult Opsanus beta were acclimated to 2.5, 5, 10, 20, 40, 60, 80, and 100% seawater (Cl(-)=545 mM) and exposed for 24 h to 2.18 microg L(-1) silver as (110m)Ag-labelled AgNO(3), a concentration close to the U.S. EPA marine criterion and less than 0.1% of the acute 96-h LC50 in seawater. Plasma osmolality, Na(+), and Cl(-) remained approximately constant from 100% down to 20-40% seawater, thereafter declining to 89% (osmolality) and 82% (Na(+), Cl(-)) of seawater values at the lowest salinity (2.5% seawater), while plasma Mg(2+) was invariant. Ionic measurements in intestinal fluids and urine supported the view that above the isosmotic point (about 32% seawater), toadfish drink the medium, absorb Na(+), Cl(-), and water across the gastrointestinal tract, actively excrete Na(+) and Cl(-) across the gills, and secrete Mg(2+) into the urine. Below this point, toadfish appear to stop drinking, actively take up Na(+) and Cl(-) at the gills, and retain ions at the kidney. Silver accumulation varied greatly with salinity, by nine-fold (whole body), 26-fold (gill tissue), and 18-fold (liver), with the maxima occurring in 2.5% seawater, the minima in 40% seawater (close to the isosmotic point), and slightly greater values at higher salinities. Highest silver concentrations occurred in liver, second highest in gills, intermediate concentrations in kidney, spleen, and gastrointestinal tissues, and lowest in swim bladder and white muscle, though patterns changed with salinity. There were substantial biliary but minimal urinary levels of silver. The salinity-dependent pattern of silver accumulation best correlated with the abundance of the neutral complex AgCl(0), though the presence of small amounts of Ag(+) at the lowest salinities may also have been important. In contrast, silver accumulation in the esophagus-stomach was greatest in 100% seawater and least at the isosmotic salinity (five-fold variation), a pattern probably explained by drinking and silver uptake into the blood through the gills. Models of silver bioavailability across salinity must consider the presence of silver-binding ligands on both gills and gastrointestinal tract, changing silver speciation, and the changing ionoregulatory physiology of the organism.

Animals↗
PubMed2004

Serotonergic regulation of membrane potential in developing rat prefrontal cortex: coordinated expression of 5-hydroxytryptamine (5-HT)1A, 5-HT2A, and 5-HT7 receptors.

The developing prefrontal cortex receives a dense serotonergic innervation, yet little is known about the actions of serotonin [5-Hydroxytryptamine (5-HT)] in this region during development. Here, we examined the developmental regulation of 5-HT receptors controlling the excitability of pyramidal neurons of this region. Using whole-cell recordings in in vitro brain slices, we identified a dramatic shift in the effects of 5-HT on membrane potential during the postnatal developmental period. In slices derived from young animals [postnatal day (P) 6 to P19], administration of 5-HT elicits a robust depolarization of layer V pyramidal neurons, which gradually shifts to a hyperpolarization commencing during the third postnatal week. This progression is the result of coordinated changes in the function of 5-HT7 and 5-HT2A receptors, which mediate different aspects of the depolarization, and of 5-HT1A receptors, which signal the late developing hyperpolarization. The loss of the 5-HT7 receptor-mediated depolarization and the appearance of the 5-HT1A receptor-mediated hyperpolarization appears to reflect changes in receptor expression. In contrast, the decline in the 5-HT2A receptor depolarization with increasing age was associated with changes in the effectiveness with which these receptors could elicit a membrane depolarization, rather than loss of the receptors per se. Together, these results outline coordinated changes in the serotonergic regulation of cortical excitability at a time of extensive synaptic development and thus suggest a key role for these receptor subtypes in the postnatal development of the prefrontal cortex.

Age Factors↗
PubMed2004

Palliative care inpatient service in a comprehensive cancer center: clinical and financial outcomes.

PURPOSE: Inpatient palliative care units are unavailable in most cancer centers and tertiary hospitals. The purpose of this article is to review the outcomes of the first 344 admissions to the Palliative Care Inpatient Service (PCIS) at our comprehensive cancer center. PATIENTS AND METHODS: We retrospectively reviewed our computerized database for clinical and demographic information, length of stay, and hospital billing during the first year of the service's operation. RESULTS: Three hundred twenty patients were admitted during the study period. Their median age was 57 years. The main cancer diagnoses were thoracic or head and neck (44%), gastrointestinal (25%), and hematologic malignancy (8%). The main referral symptoms were pain (44%), nausea (41%), fatigue (39%), and dyspnea (38%). The median length of stay in the PCIS was 7 days (range, 1 to 58 days). Fifty-nine patients died while in the PCIS. However, the overall hospital mortality rate was not increased compared with that in the year before the establishment of the PCIS (3.58% v 3.59%). The mean reimbursement rate for all palliative care charges was approximately 57%, and the mean daily charges in the PCIS were 38% lower than the mean daily charges for the rest of the hospital. Symptom intensity data showed severe distress on admission and significant improvement in the main target symptoms. Most patients were discharged to a hospice. CONCLUSION: The PCIS has been accepted in our tertiary cancer center on the basis of its clinical utility and financial viability.

Adult↗
PubMed2004

Foregut duplication cyst arising in the floor of mouth.

Enteric duplications are uncommon. A rare foregut duplication cyst arising in the floor of mouth is reported. Diagnosis of cystic lesion within the oral cavity was made in utero. Enteric duplications have not yet been attributed to a single embryogenesis but are likely to represent an error in migration of normal cells that rest in an abnormal position. Immediately following delivery of the neonate via an ex-utero intrapartum treatment (EXIT) procedure, the cyst was marsupialised but required definitive surgical excision at 5 weeks of age.

Cysts↗
PubMed2004

Phase II study of low-dose topotecan in myelodysplastic syndromes: a Hoosier Oncology Group (HOG) study.

Topotecan has demonstrable activity in high-risk MDS and CMMoL. However, the significant toxicity of topotecan administered at a dose of 2mg/m2 i.v. daily for 5 days as a continuous infusion limits its use in older patients. Therefore, we studied topotecan 1.5mg/m2 per day i.v. over 2 h for three consecutive days in 20 patients with high-risk MDS (12 RAEB; 4 RAEB-T; 4 CMMoL). Cycles were given every 4-6 weeks. Fifteen patients were evaluable for response. Only one patient achieved a durable complete remission (CR). There were three deaths within the first cycle of therapy. Severe myelosuppression was the most common toxicity. Grades 3-4 infections were documented in four patients. We conclude that topotecan administered at this dose and schedule has no clinically significant activity.

Aged↗
PubMed2003

Chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is a major cause of death and disability worldwide. Recognition that the burden of this disorder will continue to increase over the next 20 years despite medical intervention has stimulated new research into the underlying mechanisms, leading to a rational basis for evaluation of existing therapies, and has suggested novel treatment approaches. Tobacco exposure remains the main but not exclusive cause of COPD. Whether the lung is injured by changes in the balance of proteases and antiproteases, tissue damage by oxidative stress, or a combination of the two is still not known. The genetic basis of susceptibility to COPD is now being studied as is the role of computed tomography in the identification of structural damage in individuals with less symptomatic disease. Clinical diagnosis still relies heavily on an appropriate history confirmed by abnormal spirometry. Smoking cessation is possible in a substantial proportion of individuals with symptoms but is most effective if withdrawal is supported by pharmacological treatment. Treatment with long-acting inhaled bronchodilators and, in more severe disease, inhaled corticosteroids reduces symptoms and exacerbation frequency and improves health status. Rehabilitation can be even more effective, at least for a year after the treatment. Recent guidelines have made practical suggestions about how to optimise these treatments and when to consider addition of oxygen, surgery, and non-invasive ventilation. Regular review of this guidance is important if future management advances are to be implemented effectively.

Humans↗
PubMed2003

Safety of subcutaneous clodronate and efficacy in hypercalcemia of malignancy: a novel route of administration.

Bisphosphonates have become standard treatment in management of malignancy-induced hypercalcemia and malignant bone pain. One obstacle to the routine use of bisphosphonates in palliative patients is that oral bisphosphonates have low bioavailability and a degree of gastrointestinal toxicity that may explain poor compliance. Intravenous administration can be cumbersome in patients admitted to long-term care settings or at home. We have developed and tested a new way of administering clodronate via subcutaneous infusion. This retrospective cohort study evaluated 150 patients admitted to a tertiary palliative care unit from May 1996 to May 2000 who received 254 subcutaneous infusions of clodronate for hypercalcemia or bony complications. Data were collected by chart review and specifically evaluated site toxicity and biochemistry. There was minimal local toxicity and only 2 infusions needed to be discontinued because of pain at the subcutaneous site. Clodronate showed efficacy in normalizing the serum calcium within 5 days post-infusion in 32 of 43 infusions given for hypercalcemia. This study shows that subcutaneous clodronate is safe and can lower serum calcium levels in malignant hypercalcemia.

Analgesics, Non-Narcotic↗