Biomedical subjects

R Whittington

Publications and source records attributed to R Whittington.

At least 91 records · Page 5Linked to original sources

PubMed1994

Locally advanced renal cell carcinoma: low complication rate and efficacy of postnephrectomy radiation therapy planned with CT.

PURPOSE: To determine the usefulness of computed tomography (CT) in planning radiation therapy for locally advanced renal cell carcinoma after nephrectomy. MATERIALS AND METHODS: The authors retrospectively analyzed the treatment records and follow-up status of 12 consecutive patients who underwent radical nephrectomy and postoperative radiation therapy for locally advanced renal cell carcinoma. Records' of 12 consecutive patients who underwent only radical nephrectomy were also analyzed. RESULTS: None of the patients who received radiation therapy after nephrectomy had local-regional recurrence, despite disease at the surgical margins in six patients; the actuarial disease-free survival at 5 years was 75%. In contrast, the 5-year actuarial local failure rate in the surgery-only group was 30% (significant difference at P < .01) and the disease-free survival rate was 62% (mean and median follow-up was 4.6 and 5.1 years, respectively). CONCLUSION: With CT, radiation can be delivered to the renal bed safely and without undue morbidity. Given the lack of chronic complications associated with the side effects of radiation therapy and uniform local control of cancer in these patients, the role of radiation therapy in patients at high risk for local failure may be reconsidered.

Carcinoma, Renal Cell↗

PubMed1994

Hormone replacement therapy: I. A pharmacoeconomic appraisal of its therapeutic use in menopausal symptoms and urogenital estrogen deficiency.

Menopause and the accompanying reduction in estrogen production may cause a number of symptoms in women which include hot flushes, sweating, mood and sleep disturbances, fatigue and urogenital dysfunction. The effectiveness of estrogen-based hormone replacement therapy (HRT) in ameliorating these symptoms, and in preventing long term sequelae such as osteoporosis, is well established. Comparative trials indicate that oral conjugated estrogens 0.625mg, oral ethinyl estradiol 0.02mg and transdermal estradiol 0.05mg have equivalent efficacy in relief of mild to moderate menopausal symptoms and prevention of bone mineral loss. Concomitant progestogen therapy is usually prescribed for women with intact uteri to protect against endometrial hyperplasia and carcinoma. The addition of progestogen maintains and may even enhance the bone-conserving effects of estrogen, and continuous regimens appear to reduce the incidence of irregular menses. Adverse reactions are predominantly local skin irritation with transdermal preparations (14% of patients) and systemic effects common to most forms of HRT including breast tenderness, flushing, headache and irregular bleeding, occurring in less than or equal to 2% of patients. Data concerning the effect of HRT on quality of life are limited, but most analyses have assigned utility values of 0.99 for mild and 0.95 for severe menopausal symptoms. However, recent clinical data suggest that these utility values may underestimate the impact of menopausal symptoms on quality of life. The cost benefit and cost effectiveness of HRT in the treatment of menopausal symptoms have not been fully researched, although preliminary results suggest that conjugated estrogens and transdermal estradiol compare well with alternative therapies such as veralipride and Chinese medicines. A Swedish study using a prevalence-based approach estimated that estriol treatment in all women with urinary incontinence aged greater than or equal to 65 years resulted in monetary savings compared with treating 20% of women. Cost-utility data indicated that the change in quality-adjusted life years (QALYs) with HRT was always positive, but the degree of change was determined by the baseline assumptions. Estimated changes in QALYs with HRT ranged from 0.006 for 5 years of treatment with unopposed estrogen in women with intact uteri, to 0.5 for 10 years of the same treatment in women with severe menopausal symptoms following hysterectomy. Compliance with HRT is suboptimal as 5 to 50% of women withdraw from therapy, thereby increasing costs per year of life saved.(ABSTRACT TRUNCATED AT 400 WORDS)

Climacteric↗

PubMed1994

Hormone replacement therapy: II. A pharmacoeconomic appraisal of its role in the prevention of postmenopausal osteoporosis and ischaemic heart disease.

The reduction in estrogen production that occurs at menopause is associated with several long term sequelae. There is an accelerated decrease in bone mineral density leading to an increased risk of osteoporotic fracture. Furthermore, changes in plasma lipid profiles and other cardiovascular parameters increase the risk of cardiovascular and cerebrovascular pathology. These effects are additional to the menopausal symptoms experienced by many women. The effectiveness of estrogen-based hormone replacement therapy (HRT) is well established in preventing bone mineral loss and also in ameliorating menopausal symptoms, with the addition of progestogen maintaining or possibly enhancing the bone-conserving effects. However, prolonged therapy appears to be necessary to conserve bone mineral density and prevent osteoporotic fracture, particularly in women aged greater than or equal to 75 years, and compliance with long term therapy is likely to be poor. Estrogen favourably alters plasma lipid profiles, improves coronary blood flow and inhibits the central distribution of body fat. Effects on haemostatic mechanisms and coronary vasomotor response to acetylcholine have also been suggested as mechanisms for the beneficial effects of estrogen on ischaemic heart disease. The effects of concomitant progestogens on plasma lipids are variable, and may depend on the type, dosage regimen and duration of therapy. Pharmacoeconomic analyses of HRT have used a variety of risk assumptions. Relative risk rates of osteoporotic fracture and mortality from myocardial infarction are assumed to reduce to 0.5 after greater than 5 years' therapy. Long term HRT is associated with a relative risk of approximately 1.3 for breast cancer, whereas the relative risk of endometrial cancer is 4.0 to 8.0 in women with intact uteri receiving prolonged unopposed estrogen therapy. HRT that includes progestogens is assumed to incur no added risk of endometrial cancer, and this treatment is generally recommended for women with intact uteri. Data concerning the effect of HRT on quality of life are limited and utility values for hip fracture of 0.95 to 0.36 have been assigned, depending on assumptions of disability. Cost-benefit, cost-effectiveness and cost-utility studies evaluating HRT in the prevention of osteoporotic fracture have differed widely in methodology, making comparison of results difficult. HRT appears to be most economically useful in the prevention of fracture if used in women who have undergone hysterectomy, in women with high risk of osteoporotic fracture or ischaemic heart disease, and/or in women with menopausal symptoms.(ABSTRACT TRUNCATED AT 400 WORDS)

Breast Neoplasms↗

PubMed1994

Colfosceril palmitate. A pharmacoeconomic evaluation of a synthetic surfactant preparation (Exosurf Neonatal) in infants with respiratory distress syndrome.

Comprehensive clinical data provide strong evidence of the efficacy of the synthetic lung surfactant colfosceril palmitate (Exosurf Neonatal) administered as prophylaxis or rescue therapy in infants with respiratory distress syndrome (RDS). The use of rescue therapy with colfosceril palmitate is further supported by cost-effectiveness analyses which report a 9 to 48% reduction in the cost per survivor compared with placebo or historical controls, despite divergent study methodology and location. Importantly, the savings were evident in both larger (> or = 1250g) and smaller (700 to 1350g) infants. All studies considered costs or charges accrued during initial hospitalisation through to 1 year; measurement of long term resource use data and all resulting costs are required for a more complete pharmacoeconomic evaluation. The optimal timing of surfactant administration is likely to be an important economic issue given that efficacy data from a large international trial support earlier administration of colfosceril palmitate versus delayed therapy in high risk patients. Further economic benefits may be realised by the sequential use of antenatal corticosteroids and surfactant therapy, although this has yet to be prospectively investigated. In conclusion, clinical and pharmacoeconomic data strongly support the use of rescue therapy with colfosceril palmitate. Additionally, recent clinical data indicating that even better results may be achieved with earlier administration and/or combined use with antenatal corticosteroids should be assessed from an economic standpoint to determine the optimal prescribing strategy for this agent.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed1993

Anatomy of the celiac axis and superior mesenteric artery and its significance in radiation therapy.

PURPOSE: In the radiation therapy of upper gastrointestinal malignancies, treatment of lymph nodes in the region of the celiac axis and superior mesenteric axis is often mandated. This study was undertaken to determine the relationship of the celiac axis and superior mesenteric arteries to the vertebral bodies--the radiographically visualized reference structures during simulation. METHODS AND MATERIALS: Twenty-three celiac angiograms and 24 superior mesenteric angiograms performed preoperatively in 24 patients treated at the University of Pennsylvania from 1984 to 1989 for pancreatic carcinoma were examined. The location of the origin of the celiac and superior mesenteric arteries was determined in each case. RESULTS: In 48% of the celiac angiograms, the celiac axis arose from the aorta high at the pedicle of the T-12 vertebral body, contrary to the common belief that the celiac axis arises near the T12-L1 interspace. The superior mesenteric artery arose at the level of L-1 in 83% of the 24 angiograms and below the pedicle of L-1 in 5 (21%). However, none arose below the L1-2 interspace. CONCLUSION: The variability demonstrated in the levels from which these vessels arise strongly suggests individualized treatment planning, including angiographic, CT or MRI data should be performed if tight margins are used. These studies would additionally optimize treatment of the tumor bed. Consideration for dose at field edges (i.e., "buildup") and day to day variation in set-up is required in determining the field borders. Treatment volumes tightly encompassing T12 and L1 could risk undertreating regional lymph nodes associated with these vessels.

Angiography↗

PubMed1993

Rapid identification of some Leptospira isolates from cattle by random amplified polymorphic DNA fingerprinting.

We compared random amplified polymorphic DNA (RAPD) fingerprinting with cross-absorption agglutination and restriction enzyme analysis for typing bovine leptospires. Using RAPD fingerprinting, we examined a number of Leptospira serovars, namely, hardjo genotypes bovis and prajitno, pomona, balcanica, tarassovi, swajizak, kremastos, australis, and zanoni, which are likely to be isolated from Australian cattle. Each serovar and genotype had a unique RAPD profile. Of 26 field isolates of Leptospira, 23 were identified as hardjo genotype bovis subtype A, 2 were identified as zanoni, and 1 was identified as pomona by RAPD fingerprinting, and their types were confirmed by cross-absorption agglutination and restriction enzyme analysis.

Animals↗

PubMed1993

Current role of MR imaging in the staging of adenocarcinoma of the prostate.

Surgical cure of adenocarcinoma of the prostate (ACP) is possible in over 80% of cases when the disease is confined to the gland capsule. The endorectal probe for magnetic resonance (MR) imaging has increased resolution of the prostate gland and capsule, which has improved the sensitivity and specificity for staging ACP (.65 sensitivity, .69 specificity for body coil; .87 sensitivity, .85 specificity for the endorectal coil). Normal glandular regions in the peripheral zone and central zone have significantly higher citrate levels than ACP and fibromuscular and fibrous benign prostatic hyperplasia at proton spectroscopy. ACP has a higher phosphomonoester-phosphocreatine ratio than normal glandular tissue at phosphorus spectroscopy. The combination of endorectal coil MR imaging for local spread, and body coil MR imaging for advanced disease, makes MR imaging the premier imaging modality for the preoperative staging of ACP.

Adenocarcinoma↗

PubMed1993

Epoetin: a pharmacoeconomic review of its use in chronic renal failure and its effects on quality of life.

Epoetin (recombinant human erythropoietin) is an effective treatment for the anaemia of patients with chronic renal failure. It is well tolerated, and the risk of adverse effects that are caused by too rapid a correction of anaemia, for example hypertension, can be reduced in most cases by lower starting dosage regimens. Epoetin improves the quality of life of anaemic patients with end-stage renal disease (ESRD), and significant improvements in most parameters of the Kidney Disease Questionnaire, the Sickness Impact Profile and the Nottingham Health Profile have been reported by patients. However, acquisition costs of epoetin are high, thereby adding a considerable cost to ESRD therapy despite a reduction in blood transfusion requirements. Notwithstanding, although cost-effectiveness studies have indicated that epoetin is associated with higher costs of therapy, cost-benefit analysis indicates that these costs can be reduced markedly with low-dose regimens and may be completely recovered if patients regain employment.

Adolescent↗

PubMed1993

Misoprostol: pharmacoeconomics of its use as prophylaxis against gastroduodenal damage induced by nonsteroidal anti-inflammatory drugs.

Misoprostol effectively prevents nonsteroidal anti-inflammatory drugs (NSAID)-induced gastric ulcer and is the only agent currently indicated for this purpose. In addition, misoprostol is effective as prophylaxis against NSAID-induced duodenal ulcer. Because of the widespread use of NSAIDs, the cost of routine misoprostol prophylaxis would be high, and thus its pharmacoeconomic evaluation is an important factor in assessing the most appropriate role of misoprostol in this group of patients. Current cost-benefit analyses undertaken in major European centres and the US have generally indicated that, depending on initial assumptions, misoprostol prophylaxis over a 3-month period is cost-saving in patients with osteoarthritis taking NSAIDs. The net savings (costs) realised were dependent on several variables, including the acquisition cost of misoprostol, silent ulcer rate and patients' compliance. Importantly, misoprostol prophylaxis was consistently more cost-beneficial in elderly patients aged greater than 60 to 65 years than in their younger counterparts. In contrast, in one study misoprostol was found to reduce patients' quality of life and, although misoprostol therapy is potentially cost-saving to society, patients generally preferred no therapy. A single study assessing the cost-effectiveness of misoprostol prophylaxis in preventing ulcerative complications concluded that primary treatment was not an economically viable option for all NSAID users. Misoprostol was most cost-effective in the prevention of recurrent or secondary gastric ulcer complications in 'high-risk' patients, for example patients aged over 60 years and patients with rheumatoid arthritis. Thus, although there are areas of interest awaiting further pharmacoeconomic investigation, misoprostol prophylaxis appears to be cost-effective in elderly and high risk patients receiving NSAIDs. Additionally, misoprostol prophylaxis is cost-saving in elderly patients with osteoarthritis requiring NSAID therapy.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1993

Idarubicin: a pharmacoeconomic evaluation of its use in adult patients with acute myeloid leukaemia.

Idarubicin is an effective agent in the treatment of acute myeloid leukaemia (AML), inducing complete remission in 39 to 80% of newly diagnosed patients. Although it also demonstrates efficacy as monotherapy, and is of use in relapsed or refractory disease, most comparative clinical trials have administered idarubicin intravenously in combination with cytarabine in newly diagnosed patients. These trials indicate that improved survival and response rates, and rapid achievement of remission, are more likely with idarubicin than with daunorubicin, when both agents are given in combination with cytarabine. In elderly patients, however, response rates are lower than in younger patients, and there is less disparity in efficacy between idarubicin and daunorubicin induction therapy. Although AML is an expensive disease to treat, the majority of costs are associated with the length of hospitalisation, with the acquisition cost of the chemotherapy agents contributing less than 10% to overall expenditure. Idarubicin combined with cytarabine therapy achieved higher response rates with the first cycle of therapy than daunorubicin, thereby reducing the requirements for a second cycle of therapy and further hospitalisation. Compared with daunorubicin plus cytarabine induction treatment, idarubicin plus cytarabine reduced the costs of achieving a complete response by between 22 and 39% in patients with a median age less than 60 years. In patients with a median age of 62 years, who are more representative of the AML population, costs of achieving a complete response were reduced by 3 to 6%. Thus, idarubicin is more cost effective than daunorubicin as induction therapy in combination with cytarabine, in adult patients with AML. The pharmacoeconomic position of idarubicin in postinduction therapy remains to be established.

Adult↗

PubMed1992

Clinical implications of learned food aversions in patients with cancer treated with chemotherapy or radiation therapy.

BACKGROUND: The nutritional implications of learned food aversions were evaluated in patients with newly diagnosed cancer receiving either chemotherapy (n = 53) or radiation therapy (n = 49). METHODS: Aversion incidence was determined by questionnaires and a food challenge. Measures of dietary and nutritional status included ratings of appetite and chemosensory function; reported shifts of food selection and measured body weight; lymphocyte count; hematocrit; and plasma albumin, transferrin, and hemoglobin levels. Quality of life was assessed by self-ratings of mood and well-being. RESULTS: Subsequent to the initiation of treatments, aversions formed in 56% and 62% of patients receiving chemotherapy and radiation therapy, respectively. The aversions were specific (two to four items per afflicted patient) and transient (mean duration, 0.25-2 months). All types of foods and beverages were targeted. No significant association was observed between food aversion incidence and any measure of dietary complications, nutritional status, or quality of life. CONCLUSIONS: Although food aversions are a common sequela of chemotherapy and radiation therapy, they generally have limited clinical significance.

Adult↗

PubMed1992

Secondary malignant neoplasms in patients with bladder carcinoma.

At the University of Pennsylvania and its affiliates, 292 patients with bladder carcinoma treated with a variety of definitive regimens were observed for the incidence of secondary malignancies. The cumulative incidence at fifty-four months, including synchronous primary neoplasms, was 24 percent. Hazard function analysis reveals a relatively constant risk of new neoplasms to be approximately 1.5 percent per year over a period of forty-eight months after diagnosis.

Humans↗

PubMed1992

Serological responses and immunity produced in salmonids by vaccination with Australian strains of Vibrio anguillarum.

The Australian populations of rainbow trout (Onchorhynchus mykiss) and Atlantic salmon (Salmo salar) were found to have similar immunological responses to local strains of Vibrio anguillarum as those reported for the more genetically diverse populations of these fish and strains of V. anguillarum found in the Northern Hemisphere. In addition, our studies more precisely defined the respective responses of rainbow trout and Atlantic salmon to immersion vaccination by the bath and dip methods.

Animals↗

PubMed1992

Staff strain and social support in a psychiatric hospital following assault by a patient.

Attacks by patients are acknowledged as an important source of stress for psychiatric staff which has ramifications for patients and the nurses' employers as well. Twenty-three psychiatric nurses and one doctor who had been assaulted by a patient at work were interviewed within 72 hours of the incident and twice more within 2 weeks. The levels of strain they experienced and the amount of support provided for them in the time between interviews were measured and correlated. Some subjects reported high levels of strain which persisted well beyond the incident. Support was usually provided on an informal basis and was concentrated in the period immediately after the incident.

Burnout, Professional↗

PubMed1992

Alglucerase. A review of its therapeutic use in Gaucher's disease.

Alglucerase is a mannose-terminated form of human placental glucocerebrosidase, developed to treat patients with Gaucher's disease. Functional glucocerebrosidase is deficient in Gaucher's disease, an autosomal recessive lipid storage disorder that affects people of all ethnic backgrounds, but has a higher incidence among East European Jews (Ashkenazim). Gaucher's disease manifests with hepatosplenomegaly, bleeding disorders and bone disease, with the more rare subtypes (types 2 and 3) featuring neurological dysfunction. Prior to the development of enzyme replacement therapy, treatment for Gaucher's disease was mainly symptomatic relief. Primary treatment with glucocerebrosidase focuses on removal of the lipid metabolite that causes the pathology. Because of the rarity of Gaucher's disease clinical trials are small, and much of the data investigating alglucerase therapy have been obtained from studies of patients with type 1 disease, the prevalent subtype. Nonetheless, after intravenous administration of alglucerase, improvements are evident within 6 months of therapy. Patients have increased haemoglobin levels and platelet counts, and decreased incidences of epistaxis and bruising. Spleen and liver size are reduced, and skeletal parameters improve. Children gain height and most patients receiving alglucerase therapy are able to resume work and daily activities. Alglucerase is well tolerated, with few mild adverse reactions reported. Although the pharmacokinetic and pharmacodynamic information for alglucerase is limited, its unequivocal efficacy justifies enzyme replacement therapy with this compound as first-line treatment for patients with Gaucher's disease, for whom treatment options are limited.

Bone and Bones↗

PubMed1992

Zalcitabine. A review of its pharmacology and clinical potential in acquired immunodeficiency syndrome (AIDS).

Zalcitabine is an analogue of the nucleoside deoxycytidine which, when intracellularly converted to an active triphosphate metabolite, inhibits replication of human immunodeficiency virus (HIV). Zalcitabine is thought to act in the early phase of HIV replication by inhibiting reverse transcriptase and terminating the viral DNA chain. In vitro, zalcitabine is one of the more effective nucleoside analogues currently in clinical use for HIV infection, with 0.5 mumol/L concentrations completely inhibiting HIV replication in human T lymphocyte cell lines. In clinical trials, p24 antigen levels decreased and CD4 cell counts increased in patients with acquired immunodeficiency syndrome (AIDS) receiving zalcitabine > or = 0.03 mg/kg/day as monotherapy. Dose-dependent adverse effects that include peripheral neuropathy, stomatitis and rash, restrict long term use at higher dosages, and it is unclear whether zalcitabine monotherapy is as effective as zidovudine in extending survival in HIV-infected patients. Alternating or concomitant therapy with zalcitabine and zidovudine provides effective inhibition of viral replication and disease progression (as measured by improvements in CD4 cell counts) with lower and less toxic dosage regimens. At present, therefore, zalcitabine has a place in AIDS therapy both in combination with zidovudine, and as monotherapy for patients unable to tolerate zidovudine.

Acquired Immunodeficiency Syndrome↗

PubMed1992

Sparganosis in the monotremes Tachyglossus aculeatus and Ornithorhynchus anatinus in Australia.

Sparganosis in the echidna, Tachyglossus aculeatus, is characterized by large subcutaneous masses that may be confused with neoplasms. Plerocercoids, believed to be Spirometra erinacei, were found in the ventral or lateral subcutaneous tissues of three echidnas. In each case there was a prominent fibrous mass < or = 12 cm in diameter enclosing plerocercoids, which were surrounded by an intense inflammatory infiltrate dominated by plasma cells and lymphocytes, with focal suppuration. Multiple, small (< or = 2 mm) plerocercoids were present in the lungs and pleural cavity of a fourth echidna that died due to severe pneumonitis. Several plerocercoids also were found in the lung of a platypus (Ornithorhynchus anatinus) associated with parenchymal compression and focal pneumonia.

Animals↗

PubMed1992

Right ventricular support after implantation of a Novacor Left Ventricular Assist Device.

The objective was to determine which factors might help to predict the need for mechanical right ventricular support following insertion of a left ventricular assist device (LVAD). A retrospective analysis was performed on 24 patients with cardiomyopathies who had insertion of a LVAD as a bridge to heart transplantation at Presbyterian University Hospital during the period 1987 to 1991. Group 1 consisted of 18 patients who could be adequately supported with the LVAD alone, while Group 2 consisted of 6 patients who required additional support with a right ventricular assist device. Group 2 exhibited longer periods of hypotension on cardiopulmonary bypass, increased inotropic support and decreased right ventricular ejection fraction at time of chest closure post-LVAD.

Adolescent↗