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Biomedical subjects

P White

Publications and source records attributed to P White.

At least 109 records · Page 6Linked to original sources
PubMed1998

Symptom control in patients with hay fever in UK general practice: how well are we doing and is there a need for allergen immunotherapy?

BACKGROUND: Seasonal allergic rhinitis is often regarded as a trivial condition which patients should treat themselves. However, a significant proportion of sufferers are not fully controlled on standard hay fever medication, either because they do not use it properly or because their symptoms are resistant to standard therapy. The latter group may be suitable for allergen immunotherapy, which was once widely available in UK general practice but is now only available through specialist centres. AIMS: To describe the symptom control of patients with hay fever, to assess concordance with prescribed medication, and to estimate the number of patients who may benefit from referral for allergen immunotherapy. SETTING: General practices in Hampshire and Dorset, UK. METHOD: Survey of adult hay fever sufferers prescribed a non-sedating antihistamine and nasal steroid spray by their general practitioner. A postal questionnaire was sent to all eligible patients aged 16-64 registered with 16 general practices. Self-assessment of symptom control and reported compliance with medication were used to identify those patients who were suboptimally controlled and might therefore benefit from immunotherapy. RESULTS: Eight hundred and forty-six out of 62500 registered patients aged 16-64 (1.4%) were receiving both drugs, and responses were received from 627 (74.1%); 526 of these met the full entry criteria. One hundred and forty-two patients (27.0%) were using both types of drug regularly. Of the 142 patients using optimum pharmacotherapy, 54 (38.0%) reported good control of their hay fever symptoms. The remaining 62.0% experienced troublesome residual symptoms and described symptom control as partial or poor. Among those using suboptimal pharmacotherapy, 181/376 (48.1%) reported good control. CONCLUSION: Many patients are using treatment inappropriately. Current guidelines need to be applied better but there is also a significant burden of residual symptoms, even among those receiving current optimal therapy. This indicates a need for patients with severe summer hay fever to receive specialist assessment.

Adolescent↗
PubMed1998

Multicenter outcome study of cancer patients admitted to the intensive care unit: a probability of mortality model.

PURPOSE: To develop prospectively and validate a model for probability of hospital survival at admission to the intensive care unit (ICU) of patients with malignancy. PATIENTS AND METHODS: This was an inception cohort study in the setting of four ICUs of academic medical centers in the United States. Defined continuous and categorical variables were collected on consecutive patients with cancer admitted to the ICU. A preliminary model was developed from 1,483 patients and then validated on an additional 230 patients. Multiple logistic regression modeling was used to develop the models and subsequently evaluated by goodness-of-fit and receiver operating characteristic (ROC) analysis. The main outcome measure was hospital survival after ICU admission. RESULTS: The observed hospital mortality rate was 42%. Continuous variables used in the ICU admission model are PaO2/FiO2 ratio, platelet count, respiratory rate, systolic blood pressure, and days of hospitalization pre-ICU. Categorical entries include presence of intracranial mass effect, allogeneic bone marrow transplantation, recurrent or progressive cancer, albumin less than 2.5 g/dL, bilirubin > or = 2 mg/dL, Glasgow Coma Score less than 6, prothrombin time greater than 15 seconds, blood urea nitrogen (BUN) greater than 50 mg/dL, intubation, performance status before hospitalization, and cardiopulmonary resuscitation (CPR). The P values for the fit of the preliminary and validation models are .939 and .314, respectively, and the areas under the ROC curves are .812 and .802. CONCLUSION: We report a disease-specific multivariable logistic regression model to estimate the probability of hospital mortality in a cohort of critically ill cancer patients admitted to the ICU. The model consists of 16 unambiguous and readily available variables. This model should move the discussion regarding appropriate use of ICU resources forward. Additional validation in a community hospital setting is warranted.

Academic Medical Centers↗
PubMed1998

Integrated exposure uptake biokinetic model for lead in children: empirical comparisons with epidemiologic data.

The concept of model validation is evolving in the scientific community. This paper addresses the comparison of observed and predicted estimates as one component of model validation as applied to the integrated exposure uptake biokinetic (IEUBK) model for lead in children. The IEUBK model is an exposure (dose)-response model that uses children's environmental lead exposures to estimate risk of elevated blood lead (typically > 10 micrograms/dl) through estimation of lead body burdens in a mass balance framework. We used residence-specific environmental lead measurements from three epidemiologic datasets as inputs for the IEUBK model to predict blood lead levels, and compared these predictions with blood lead levels of children living at these residences. When the IEUBK modeling focused on children with representative exposure measurements, that is, children who spent the bulk of their time near the locations sampled, there was reasonably close agreement between observed and predicted blood lead distributions in the three studies considered. Geometric mean observed and predicted blood lead levels were within 0.7 microgram/dl, and proportions of study populations expected to be above 10 micrograms/dl were within 4% of those observed.

Age Factors↗
PubMed1998

Real-time bronchoscope tip localization enables three-dimensional CT image guidance for transbronchial needle aspiration in swine.

STUDY OBJECTIVE: To determine the feasibility of using real-time bronchoscope position technology coupled with previously acquired three-dimensional CT data to enhance transbronchial needle aspiration (TBNA). DESIGN: Eight swine were given percutaneously created target lesions for TBNA. A miniature position sensor was placed at the tip of a bronchoscope, and real-time position information during bronchoscopy was presented on a monitor simultaneously displaying previously acquired three-dimensional CT data. INTERVENTIONS: TBNA of target lesions and submucosal ink-spot injection of computer-generated targets. MEASUREMENTS AND RESULTS: TBNA specimens revealed successful aspiration of target material. Distances between ink marks made at computer-generated tracheal targets varied, on average (+/- SD), 4.2 mm +/- 2.6 mm from predetermined computer-distance coordinates. CONCLUSION: Real-time bronchoscope position technology coupled with previously acquired CT images may aid with TBNA of nonvisible extrabronchial lesions.

Animals↗
PubMed1998

Quality assessment through patient self-report of symptoms prefiberoptic and postfiberoptic bronchoscopy.

STUDY OBJECTIVE: To apply the principles of quality improvement to measure the frequency and severity of symptoms that result from fiberoptic bronchoscopy (FOB), and to identify opportunities to improve FOB practice by identifying factors about patients and the process of care that predict these symptoms. DESIGN: Concurrent longitudinal cohort study. PATIENTS: Four hundred ninety-three adult patients who underwent FOB. MEASUREMENTS AND RESULTS: Patients completed questionnaires just prior to FOB and again at 48 h postprocedure. Patients were asked to rate the severity of nose pain, throat pain, swallowing pain, and chest pain, and the frequency of coughing, hemoptysis, phlegm, shortness of breath, wheezing, difficulty swallowing, fever, and chills. Symptom severity was reported on a four-point ordinal scale. FINDINGS: Significant worsening was found for nose pain, throat pain, swallowing pain, and hemoptysis. Shorter patients experienced more throat pain and hemoptysis, and longer procedure time predicted nose pain and hemoptysis. CONCLUSIONS: Bronchoscopy causes nose pain, throat pain, swallowing pain, and hemoptysis to a larger extent than previously has been recognized. There are opportunities to improve the patient experience with bronchoscopy by using smaller bronchoscopes in shorter patients, shortening the procedure length, and reanesthetizing the nares in longer procedures.

Adult↗
PubMed1998

Enhanced antitumour effect of liposomal daunorubicin using antibody-phospholipase C conjugates or fusion protein.

We have developed a new two-step method for targeting cytotoxic drugs to tumour cells. The method firstly involves the binding to tumour cells of antibody-phospholipase C immunoconjugates or fusion proteins. Further to washing or clearance of the immunoconjugates, liposomes are introduced which are specifically lysed at the tumour site by PLC to release their cytotoxic contents in the vicinity of the tumour cells. For two alternative human cell lines, a synergistic inhibition of cell proliferation was seen for combined treatment with a specific immunoconjugate and daunorubicin encapsulated liposomes. For tumour xenografts in mice, the combined treatment resulted in an inhibition of tumour growth although with no eradication of tumours at the doses used. The two-step antibody-PLC/liposome approach offers broad possibilities for the precise delivery of payloads of cytotoxic drugs to tumour sites.

Animals↗
PubMed1998

Learners' experience of continuing medical education events: a qualitative study of GP principals in Dorset.

BACKGROUND: General practitioners' (GPs') attendance at continuing medical education (CME) events has increased since the introduction of the Post Graduate Educational Allowance (PGEA) in 1990. However, few studies have examined doctors' perceptions about their continuing education, and explored their views in depth. AIM: To investigate general practitioners' experience of CME events, what personal impact they had, and how the GPs perceived the influence of CME in their professional practice and patient care. METHOD: A qualitative study, with in-depth semi-structured interviews, of a purposive sample of 25 general practitioners in Dorset was conducted. Content analysis was used to identify major themes from the transcripts. RESULTS: GPs perceived CME events as beneficial. Confidence levels rose, and the events provided a break from practice that refreshed and relaxed, thus indirectly benefiting patients. The opportunities provided by formal events for informal learning and exchange of ideas, with both peers in general practice and consultant colleagues, were highly valued. The relevance of the subject to general practice, and the appropriateness of the educational format, were considered of paramount importance. Few responders identified major changes in their practice as a result of formal CME events, and information was seldom disseminated among practice colleagues. CONCLUSION: The results of this study challenge GP educators to provide CME that is relevant, to recognize the value of peer contact, and to facilitate the incorporation of new information into practice.

Data Collection↗
PubMed1997

Steroid 21-hydroxylase expression and activity in human lymphocytes.

Steroid 21-hydroxylase encoded by CYP21 is expressed in adrenal cortex. Mutations in CYP21 cause potentially lethal congenital adrenal hyperplasia (CAH). Earlier observations suggested alternative sources of 21-hydroxylase activity, although its genetic source remains unclear. We found a novel source of CYP21 expression in normal human cultured B lymphocytes. The quantity of 21-hydroxylase transcript was reduced in B cell lines of CAH subjects compared with that in normal B-lymphoblastoid cells. No CYP21 transcript was detected in lymphocytes from a CAH patient with homozygous CYP21 deletion. Cultured lymphoid cells, including those carrying homozygous CYP21 deletion, and peripheral blood leukocytes converted both 17-hydroxyprogesterone to 11-deoxycortisol and progesterone to deoxycorticosterone. We conclude that lymphocytes express CYP21, but also possess a 21-hydroxylase distinct from CYP21. Activity of this isozyme may partially compensate for severe adrenal 21-hydroxylase deficiency.

Adrenal Hyperplasia, Congenital↗
PubMed1997

Postoperative reparalysis after rocuronium following nebulized epinephrine.

PURPOSE: We report a case of postoperative reparalysis in the recovery room, following nebulized epinephrine. The patient was pharmacologically reversed with edrophonium after paralysis with rocuronium. CLINICAL FINDINGS: A 12-yr-old girl developed postoperative reparalysis following the intraoperative administration of rocuronium. A total of 0.92 mg.kg-1 rocuronium was administered. After surgery, pharmacological reversal was achieved with 20 mg edrophonium with 0.15 mg atropine sulfate iv 35 min after the last administration of rocuronium. Muscular relaxation was monitored using an ulnar peripheral nerve stimulator (PNS). After reversal, a full train-of-four and sustained tetanus at 50 Hz were present. In the recovery room, following nebulized epinephrine, the patient became apneic. The patient was paralyzed and an ulnar PNS demonstrated only one faint twitch. The paralysis was reversed with 1.5 mg neostigmine with 0.3 mg glycopyrrolate. CONCLUSION: Postoperative reparalysis following rocuronium may be a cause of postoperative respiratory distress. The definitive diagnosis is made using PNS and observing the response to pharmacological reversal. Nebulized epinephrine may have a previously undescribed role in the development of postoperative reparalysis.

Administration, Inhalation↗
PubMed1997

Laparoscopic salvage of malfunctioning peritoneal catheters.

BACKGROUND: Malfunction of peritoneal catheters due to mechanical outflow problems is an annoying complication in patients undergoing chronic peritoneal dialysis (PD). Correction often involves catheter replacement or revision via laparotomy. METHODS: Twenty-five patients undergoing PD who developed mechanical catheter flow restriction underwent 28 laparoscopic procedures. Preoperative diagnoses were made by contrast catheter radiography and were: catheter sequestration (36%), omental wrap (64%). Pneumoperitoneum was induced after general anesthesia and laparoscopy was performed using a Storz laparoscope. The catheter was then identified and manipulation was attempted using instruments placed percutaneously. RESULTS: In 26 cases (93%), the catheter was freed and function restored. In two cases (7%), adhesions were so numerous and dense that the distal catheter could not be visualized. Four episodes of peritonitis developed subcutaneous leakage of peritoneal fluid which responded to cessation of PD for 2 weeks. Four patients had recurrent occlusions; three of these were managed laparoscopically. Two patients developed late hernias at the site of insertion of the laparoscope. Catheter patency averaged 9.2 months postoperatively. CONCLUSIONS: Laparoscopic revision is a successful technique for salvage of occluded peritoneal catheters.

Adult↗
PubMed1997

Resting right ventricular function in patients with coronary artery disease: pressure volume analysis using conductance catheters.

Right ventricular pressure volume cycles from patients with coronary artery disease were created in order to assess their characteristics and the effects of peak ventricular pressure and right and left artery coronary disease. Thirty-three patients undergoing diagnostic catheterisation for ischaemic heart disease underwent right ventricular catheterisation with a micromanometer and a conductance catheter. Simultaneous pressure and volume signals were recorded and analysed as functions of time, and of each other, forming pressure volume cycles. A total of 19/33 (58%) patients had an abnormal pressure volume loop with a clear end systolic shoulder, and an isovolumic relaxation phase. The mean peak ventricular pressure for all patients was raised (35.2 S.D. 11.8 mmHg), but there was no correlation between indices of shape and peak systolic pressure. Values of dP/dtmax were also raised, but there was no significant difference in this or any other index between patients with left or right coronary artery disease. Thus, in patients with coronary artery disease, the right ventricular pressure volume loop is frequently abnormal in a pattern that is recognised as a feature of an increased ventricular afterload.

Angina Pectoris↗
PubMed1997

Clinical application of the conductance catheter technique in the adult human right ventricle.

This study examines the use of conductance catheters to assess human right ventricular volume. Ten patients undergoing diagnostic cardiac catheterisation underwent right heart catheterisation with a conductance catheter and micromanometer, and a thermodilution catheter before and after fluid loading. Parallel wall conductance (Vc), and the multiplication factor relating conductance and thermodilution derived stroke volumes (å) were derived at each steady state. Pressure-volume cycles were analyzed at steady state and during fluid loading. Fluid loading resulted in a significant increase in cardiac output, and change in maximum and minimum cycle volume. There was no significant change in å (mean 0.40 S.D. 0.20) or Vc (mean 126.4 S.D. 59.6 ml) at higher cardiac outputs or ventricular volumes. Right ventricular pressure-volume cycles were formed demonstrating characteristic lack of clear isovolumic contraction and relaxation phases, and low cycle efficiencies (mean 0.62 S.D. 0.16). Serial cycles recorded during volume loading defined an end systolic pressure-volume relation more reliably than a stroke work end diastolic volume relation. Thus, a conductance derived volume signal can be obtained in the human right ventricle which can be interpreted as a continuous and instantaneous index of right ventricular volume, allowing the construction of real time pressure-volume cycles.

Adult↗
PubMed1997

Utility of fiberoptic bronchoscopy in bone marrow transplant patients.

Fiberoptic bronchoscopy (FOB) has been reported to have a high diagnostic yield and to be safe in BMT patients with pulmonary infiltrates. At our institution, BMT patients with respiratory symptoms and/or pulmonary infiltrates had a thoracic CT and bronchoalveolar lavage (BAL). Transbronchial biopsy (TBBx) was considered if the platelet count could be raised to >30 x 10(9)/l. From March 1993 to August 1995, 52 patients had 68 FOBs (42 BAL + TBBx, 26 BAL only) for 60 episodes of clinical pneumonia. Patients' characteristics were: 38 males, mean age 42 years, and 39 allogeneic BMTs. Of the 68 FOBs, 47 were performed to evaluate diffuse infiltrates, 10 were done on mechanically ventilated patients, and 50 of the FOBs were preceded by a platelet transfusion. Thirty-one percent of FOBs (21 FOBs, 19 patients) were diagnostic. Twenty-four percent of FOBs (11 diagnostic FOBs, six nondiagnostic FOBs) changed therapy. Ten complications (15%) occurred in 10 FOBs (five acute respiratory failure, three pneumothoraces, one nose bleed, one death). Hospital and 6-month survival based on episodes of clinical pneumonia were 47 and 32%, respectively. Patients who had a diagnostic FOB or a FOB that changed treatment did not have better hospital or 6-month survival compared to patients who had FOBs that were nondiagnostic or did not change treatment. FOB in our BMT patient population, had a low diagnostic yield (31%), infrequently changed treatment (24%), a significant complication rate (15%) and was not associated with improved patient survival. The role of routine diagnostic FOB in BMT patients with pulmonary infiltrates and/or respiratory symptoms should be reevaluated.

Adolescent↗
PubMed1997

A humanized antibody against human cytomegalovirus (CMV) gpUL75 (gH) for prophylaxis or treatment of CMV infections.

A humanized monoclonal antibody that binds to the 86-kDa glycoprotein, gpUL75 (gH), of human cytomegalovirus (CMV) has been developed. The six complementarity determining regions of the heavy and light chains of the mouse antibody HCMV16 were transferred to human antibody framework sequences and combined with human antibody constant regions to produce a complete antibody. The reshaped antibody recognized cells infected with a variety of virus strains and neutralized clinical isolates of CMV as efficiently as laboratory strains in a conventional plaque reduction assay. This antibody provides a potential agent for the prevention or treatment of CMV infections in humans.

Amino Acid Sequence↗