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Biomedical subjects

P Hall

Publications and source records attributed to P Hall.

At least 37 records · Page 2Linked to original sources
PubMed2002

Spectrophotometric intracutaneous analysis: a new technique for imaging pigmented skin lesions.

BACKGROUND: Spectrophotometric intracutaneous analysis (SIA) is a new technique for imaging pigmented skin lesions and for diagnosing melanoma. The SIAscope produces eight narrow-band spectrally filtered images of the skin over an area of 24 x 24 mm with radiation ranging from 400 to 1000 nm. OBJECTIVES: To present the early results of a clinical trial with SIA. METHODS: Spectrophotometric inputs from the skin were analysed using complex algorithms to return high-resolution information regarding total melanin content of the epidermis and papillary dermis, collagen and haemoglobin content as well as the presence of melanin in the papillary dermis. RESULTS: Simple, highly reproducible and reliable features were identified, e.g. the presence of dermal melanin, collagen holes and 'erythematous blush' with blood displacement. These simple features were found to be highly specific (80.1%) and sensitive (82.7%) for melanoma in a dataset of 348 pigmented lesions (52 melanomas) and compared very favourably with dermatoscopy when analysed using receiver-operator characteristic curves. CONCLUSIONS: This first clinical trial with SIAscopy has yielded very promising results and delivers new, useful information to the clinician diagnosing pigmented skin lesions.

Collagen↗
PubMed2001

The effect of TBT on the structure of a marine sediment comunity--a Boxcosm study.

The effect of tri-n-butyl tin (TBT) on an intact marine sediment community after five months exposure was investigated. Changes in the structure of macro- and meiofauna communities were determined, as well as the functional diversity of the microbial community using BIOLOG microplates for Gram negative bacteria. Development of tolerance in the microbial community was investigated using Pollution Induced Community Tolerance (PICT) experiments with fluxes of nutrients as effect indicators. TBT affected the structure and recruitment of the macro- and meiofauna at nominal additions of 30-137 micromol TBT/m2 sediment. Number of species, diversity, biomass and community similarity was reduced at these concentrations compared to control. Species that molt seemed to be the most tolerant since they were predominant in boxes that had received the highest TBT addition and echinoderms were the most sensitive species. Renewed addition of TBT in PICT experiments with sediment from each boxcosm showed that TBT had an effect on individual nutrient fluxes from all sediments. Analyses of the flux patterns revealed a memory of previous TBT exposure, either due to induced tolerance or other community conditioning.

Adaptation, Physiological↗
PubMed2001

Breast cancer risk in women with a primary ovarian cancer--a case-control study.

Register-based studies show that women with ovarian cancer are at increased risk of developing breast cancer. Primary suggested explanations are heredity factors and a common hormonal aetiology. However, clinical surveillance that is provided for cancer patients during, and after, treatment of their primary malignancies together with possible mistakes in the registering procedures could affect the risk estimates. In order to examine these factors in women registered with ovarian cancer who develop subsequent breast cancer, a case-control study was performed. Using a regional Swedish cancer registry including 5060 women registered with ovarian cancer, 89 cases of breast cancer were found. After corrections for discrepancies in the registered and recorded information, 75 cases remained, of which 72 cases were included in the study. Information concerning possible risk factors were extracted from hospital records and compared with 177 matched controls. Suggested risk factors such as parity (relative risk (RR)=1.41), late age at menopause (52-61 years; RR=1.61) and heredity for breast and/or ovarian cancer (RR=1.50) were all connected with a non-significant increased risk of subsequent breast cancer. In all, 43% of the breast cancer cases were revealed without preceding symptoms at clinical follow-up, indicating that increased clinical surveillance is a factor of importance when explaining the increased risk. The fact that only 75 (missing records included) out of the 89 registered breast cancer cases could be linked to the preceding ovarian cancer indicates that the actual risk of developing breast cancer is smaller than previously described. The clinical implications from these findings could be that, beside general screening programmes and health controls offered to women in cancer-prone families, additional mammography examinations based on the assumption of an increased risk of breast cancer are not warranted in ovarian cancer patients.

Adult↗
PubMed2001

Role of macrophage migration inhibitory factor (MIF) in murine antigen-induced arthritis: interaction with glucocorticoids.

(MIF) is a broad-spectrum proinflammatory cytokine implicated in human rheumatoid arthritis. The synthesis of MIF by synovial cells is stimulated by glucocorticoids, and previous studies suggest that MIF antagonizes the anti-inflammatory effects of glucocorticoids. This has not been established in a model of arthritis. We wished to test the hypothesis that MIF can act to reverse the anti-inflammatory effects of glucocorticoids in murine antigen-induced arthritis (AIA). Cutaneous DTH reactions and AIA were induced by intradermal injection and intra-articular injection, respectively, of methylated bovine serum albumin in presensitized mice. Animals were treated with anti-MIF MoAbs, recombinant MIF, and/or dexamethasone (DEX). Skin thickness of DTH reactions was measured with callipers and arthritis severity was measured by blinded quantitative histological assessment of synovial cellularity. Cutaneous DTH to the disease-initiating antigen was significantly inhibited by anti-MIF MoAb treatment (P < 0.001). AIA was also significantly inhibited by anti-MIF MoAb (P < 0.02). DEX treatment induced a dose-dependent inhibition of AIA, which was significant at 0.2 mg/kg (P < 0.05). MIF treatment reversed the effect of therapeutic DEX on AIA (P < 0.001). DEX also significantly inhibited DTH reactions (P < 0.05) but rMIF had no effect on this effect of DEX. DTH and AIA are MIF-dependent models of inflammation and arthritis. The reversal of glucocorticoid suppression of AIA by MIF supports the concept that MIF is a counter-regulator of glucocorticoid control of synovial inflammation. Although DTH was observed to be MIF-dependent and glucocorticoid-sensitive, rMIF had no reversing effect on the suppression of DTH by glucocorticoids. This suggests that inflammatory processes in specific tissues may respond differently to MIF in the presence of glucocorticoids.

Animals↗
PubMed2001

Interdisciplinary education and teamwork: a long and winding road.

PURPOSE: This article examines literature on interdisciplinary education and teamwork in health care, to discover the major issues and best practices. METHODS: A literature review of mainly North American articles using search terms such as interdisciplinary, interprofessional, multidisciplinary with medical education. MAIN FINDINGS: Two issues are emerging in health care as clinicians face the complexities of current patient care: the need for specialized health professionals, and the need for these professionals to collaborate. Interdisciplinary health care teams with members from many professions answer the call by working together, collaborating and communicating closely to optimize patient care. Education on how to function within a team is essential if the endeavour is to succeed. Two main categories of issues emerged: those related to the medical education system and those related to the content of the education. CONCLUSIONS: Much of the literature pertained to programme evaluations of academic activities, and did not compare interdisciplinary education with traditional methods. Many questions about when to educate, who to educate and how to educate remain unanswered and open to future research.

Communication↗
PubMed2001

Serendipitous ripples: unexpected outcomes of a palliative care educational project.

The Institute of Palliative Care in Ottawa, Canada, began its continuing education programs in 1994. Since 1997, the Institute has been developing and delivering a community-based, interdisciplinary palliative care educational program in each of the three regions of its jurisdiction. Members of the local communities work in active partnership with the faculty in the planning, implementation, and delivery of the programs. The comprehensive evaluation strategy includes a component referred to as "serendipitous ripples." These are outcomes that resulted directly from the programs, but were not anticipated. These outcomes reflect impacts on individuals and groups across the three regions and represent some significant impacts in the communities that should improve care of the terminally ill.

Education, Medical, Continuing↗
PubMed2001

Comparison of the ex vivo chemosensitivity of uveal and cutaneous melanoma.

Cutaneous and uveal melanoma both have a poor prognosis and chemotherapy is usually unsuccessful. We have previously reported the activity of a number of cytotoxic agents against metastatic cutaneous and primary choroidal uveal melanoma using an ex vivo adenosine triphosphate (ATP)-based chemosensitivity assay (ATP-TCA). In this study we compare the results obtained with the two types of melanoma. Cutaneous melanoma deposits in skin and lymph nodes (n = 58) and choroidal melanomas (n = 77) were tested using the ATP-TCA. Analysis of the data based on an arbitrary threshold for sensitivity shows that both types of melanoma exhibit heterogeneity of sensitivity to all the agents and combinations tested. With all the single agents except gemcitabine, cutaneous melanomas showed greater sensitivity in the assay, though this did not achieve statistical significance. This was also true with the drug combinations, with the exception of treosulfan + gemcitabine, which had similar activity in each type of melanoma. Of all the single agents tested, doxorubicin (47% of specimens classed as sensitive), vinorelbine (43%), treosulfan (41%) and paclitaxel (33%) showed the greatest activity with cutaneous melanoma. In the uveal melanoma samples, mitoxantrone (33%), gemcitabine (22%) and treosulfan (21%) showed the greatest activity. In contrast to the cutaneous melanomas, 13% of the uveal melanomas were sensitive to paclitaxel, 4% were sensitive to doxorubicin and 11% were found to be sensitive to vinorelbine. Both tumour types showed greater sensitivity to combinations of cytotoxic agents. The combination of treosulfan + gemcitabine was universally effective, with 72% of cutaneous melanomas and 80% of uveal melanomas exhibiting activity at the level selected to indicate sensitivity in the assay, though this will not necessarily indicate a similar level of clinical sensitivity.

Adenosine Triphosphate↗
PubMed2001

Mortality after cerebral angiography with or without radioactive Thorotrast: an international cohort of 3,143 two-year survivors.

There are few studies on the long-term sequelae of radionuclides ingested or injected into the human body. Patients exposed to radioactive Thorotrast in the 1930s through the early 1950s provide a singular opportunity, since the administration of this radiographic contrast agent resulted in continuous exposure to alpha particles throughout life at a low dose rate. We evaluated cause-specific mortality among an international cohort of 3,143 patients injected during cerebral angiography with either Thorotrast (n = 1,736) or a similar but nonradioactive agent (n = 1,407) and who survived 2 or more years. Standardized mortality ratios (SMRs) for Thorotrast and comparison patients were calculated, and relative risks (RR), adjusted for population, age and sex, were obtained by multivariate statistical modeling. Most patients were followed until death, with only 94 (5.4%) of the Thorotrast patients known to be alive at the closure of the study. All-cause mortality (n = 1,599 deaths) was significantly elevated among Thorotrast subjects [RR 1.7; 95% confidence interval (CI) 1.5-1.8]. Significantly increased relative risks were found for several categories, including cancer (RR 2.8), benign and unspecified tumors (RR 1.5), benign blood diseases (RR 7.1), and benign liver disorders (RR 6.5). Nonsignificant increases were seen for respiratory disease (RR 1.4) and other types of digestive disease (RR 1.6). The relative risk due to all causes increased steadily after angiography to reach a threefold RR at 40 or more years (P < 0.001). Excess cancer deaths were observed for each decade after Thorotrast injection, even after 50 years (SMR 8.6; P < 0.05). Increasing cumulative dose of radiation was directly associated with death due to all causes combined, cancer, respiratory disease, benign liver disease, and other types of digestive disease. Our study confirms the relationship between Thorotrast and increased mortality due to cancer, benign liver disease, and benign hematological disease, and suggests a possible relationship with respiratory disorders and other types of digestive disease. The cumulative excess risk of cancer death remained high up to 50 years after injection with >20 ml Thorotrast and approached 50%.

Adult↗
PubMed2001

Intrauterine exposure to diagnostic X rays and risk of childhood leukemia subtypes.

The relationship between childhood leukemia and prenatal exposure to low-dose ionizing radiation remains debatable. This population-based case-control study investigated the association between prenatal exposure to diagnostic X-ray examinations (for different types of examinations and at different stages of pregnancy) and the risk of childhood lymphatic and myeloid leukemia. All children born and diagnosed with leukemia between 1973-1989 in Sweden (578 lymphatic and 74 myeloid) were selected as cases, and each was matched (by sex and year of birth) to a healthy control child (excluding Down's syndrome). Exposure data were abstracted blindly from all available medical records. Odds ratios (OR) and 95% confidence intervals (CI) were calculated by conditional logistic regression. It was found that prenatal X-ray examinations resulting in direct fetal exposure were not associated with a significant overall increased risk for childhood leukemia (OR = 1.11, 95% CI 0.83-1.47), for lymphatic leukemia (OR = 1.04, 95% CI 0.77-1.40), or for myeloid leukemia (OR = 1.49, 95% CI 0.48-4.72). There was little evidence of a dose response or variation in risk by trimester of exposure or age at diagnosis. Thus X-ray examinations performed during pregnancy in the 1970s and 1980s in Sweden did not affect the risk of childhood leukemia discernibly.

Adolescent↗
PubMed2001

Discussing end-of-life issues with patients: reflections on developing an interviewing template to assist first-year medical students.

First-year medical students at the University of Ottawa currently use an interview template to work with patients who have chronic illnesses. A second-year medical student (JJ) modified the template to facilitate the discussion of death and end-of-life care by students who may have had little previous experience with such sensitive topics. The modification was accomplished using the following strategies: a systematic literature review on long-term care or nursing home residents' end-of-life needs; participation in a support group for families of dying patients; volunteering in a day hospice program for two months; piloting the template with two palliative care patients, one resident of a long-term care facility, and one family member. The paper summarizes and reflects on the process.

Aged↗
PubMed2000

Treatment-associated leukemia following testicular cancer.

BACKGROUND: Men with testicular cancer are at an increased risk of leukemia, but the relationship to prior treatments is not well characterized. The purpose of our study was to describe the risk of leukemia following radiotherapy and chemotherapy for testicular cancer. METHODS: Within a population-based cohort of 18 567 patients diagnosed with testicular cancer (from 1970 through 1993), a case-control study of leukemia was undertaken. Radiation dose to active bone marrow and type and cumulative amount of cytotoxic drugs were compared between 36 men who developed leukemia and 106 matched control patients without leukemia. Conditional logistic regression was used to estimate the relative risk of leukemia associated with specific treatments. All P values are two-sided. RESULTS: Radiotherapy (mean dose to active bone marrow, 12.6 Gy) without chemotherapy was associated with a threefold elevated risk of leukemia. Risk increased with increasing dose of radiation to active bone marrow (P for trend =.02), with patients receiving radiotherapy to the chest as well as to the abdominal/pelvic fields accounting for much of the risk at higher doses. Radiation dose to active bone marrow and the cumulative dose of cisplatin (P for trend =.001) were both predictive of excess leukemia risk in a model adjusted for all treatment variables. The estimated relative risk of leukemia at a cumulative dose of 650 mg cisplatin, which is commonly administered in current testicular cancer treatment regimens, was 3.2 (95% confidence interval = 1.5-8.4); larger doses (1000 mg) were linked with statistically significant sixfold increased risks. CONCLUSIONS: Past treatments for testicular cancer are associated with an increased risk of leukemia, with evidence for dose-response relationships for both radiotherapy and cisplatin-based chemotherapy. Statistically nonsignificant excesses are estimated for current radiotherapy regimens limited to the abdomen and pelvis: Among 10 000 patients given a treatment dose of 25 Gy and followed for 15 years, an excess of nine leukemias is predicted; cisplatin-based chemotherapy (dose, 650 mg) might result in 16 cases of leukemia. The survival advantage provided by current radiotherapy and chemotherapy regimens for testicular cancer far exceeds the small absolute risk of leukemia.

Adult↗
PubMed2000

Mortality in the offspring of individuals living along the radioactively contaminated Techa River: a descriptive analysis.

From 1949 onwards, radioactive waste was released into the Techa River in the southern Urals and the population living along the river was exposed to ionising radiation. Relocation of these people did not start until several years later, causing many individuals to be exposed to substantial doses from internal and external radiation. The identification and follow-up of the exposed individuals started more than 40 years ago and is still continuing. The Techa River offspring cohort (TROC) that has recently been established, comprises 10,459 children born to at least one parent living along the Techa River during the period 1950-1992. Of these children, 3,897 were born during the period of highest release, i.e. between 1950 and 1956 and might thus have been exposed in utero. A total of 1,103 individuals have since died mainly due to infectious and respiratory diseases, injury and poisoning. Only 25 cases were identified as having died of a malignant condition. The radioactive contamination of the Techa River in the southern Urals gives a unique possibility to study the adverse effects of protracted exposure to ionising radiation in a large well-described cohort. The Techa River offspring cohort will make it possible to study the effects on those exposed in utero or early in life and the follow-up of the cohort in the future is, therefore, of great importance. Comparisons with other cohorts of humans exposed early in life, will increase our knowledge in this field of research.

Cohort Studies↗
PubMed2000

Overestimated risk of second primary malignancies in ovarian cancer patients.

Registry-based cohort studies have established an increased risk of developing second primary malignancies (SPM) in patients with a primary ovarian cancer. In order to examine the accuracy of cancer registration with emphasis on registration of SPM, 344 women with ovarian cancer and 379 subsequent SPM, registered between 1958 and 1992 in the Stockholm-Gotland Cancer Registry (SGCR), a division of the Swedish Cancer Registry (SCR), were investigated. Complete records including pathology reports were examined and an additional histopathological evaluation was conducted for a sample of the group. The results revealed that 28 diagnoses of SPM were incorrectly registered (14 cases were misdiagnosed SPM of the gastrointestinal tract, mainly colon and rectum) and 34 women (with 38 SPM) were incorrectly registered with ovarian cancer. Recalculations of the risk of a subsequent cancer were performed on the basis of these findings and the results suggest an overestimation of the risk of developing SPM. Inferences of these findings to other primary sites of multiple malignancies should be made with caution and further studies are needed.

Cohort Studies↗