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Biomedical subjects

J M Paterson

Publications and source records attributed to J M Paterson.

At least 19 recordsLinked to original sources
PubMed2004

Future possibilities of the Linac Coherent Light Source.

A study of the potential for the development of the Linac Coherent Light Source (LCLS) beyond the specifications of the baseline design is presented. These future developments include delivery of X-ray pulses in the 1 fs regime, extension of the spectral range, increase of the FEL power, exploitation of the spontaneous emission, and a more flexible time structure. As this potential is exploited, the LCLS can maintain its role as a world-leading instrument for many years beyond its commissioning in 2008 and initial operation as the world's first X-ray free-electron laser.

Journal Article↗
PubMed2001

Role of family physicians in hospitals. Did it change between 1977 and 1997?

OBJECTIVE: To investigate whether hospital activities and attitudes toward hospitals of members of an urban family medicine department changed between 1977 and 1997. To explore whether these activities and attitudes are different among fee-for-service (FFS) and non-FFS physicians in 1997. DESIGN: Cross-sectional surveys by interview (1977) and self-administered questionnaire (1997). SETTING: Community-based family practices in Hamilton, Ont. PARTICIPANTS: In 1977, 88 of 89 (98.9%) and, in 1997, 66 of 88 (75.0%) members of the Department of Family Medicine at St Joseph's Hospital in Hamilton. MAIN OUTCOME MEASURES: Perceived reasons for involvement in hospital work; time spent and main activities in hospital; use of hospital privileges; attitudes toward family physicians' role in hospital, hospital work, and the Department of Family Medicine; perceptions of patients', consultants', and hospital administrators' attitudes toward family physicians' role in hospitals. RESULTS: In 1977 and 1997, patient care and continuing education remained key reasons for doing hospital work. In 1997, however, respondents spent a mean of 3 hours less per week in hospital; used the hospital less often for procedures, meetings, and teaching; and assumed less responsibility for their patients' in-hospital care. While perceptions of hospital work changed over the years, most physicians continued to see a need and have a desire to remain involved in hospitals. Fee-for-service and non-FFS physicians held different opinions on the needs of both hospitalized patients and family physicians. CONCLUSION: Although physicians' hospital activities and attitudes changed between 1997 and 1997, most continued to see a need and have a desire to remain involved in hospitals.

Attitude of Health Personnel↗
PubMed2000

Characterisation of human adenylyl cyclase IX reveals inhibition by Ca(2+)/Calcineurin and differential mRNA plyadenylation.

The functional diversity of adenylyl cyclases provides for different modes of cyclic AMP signalling in mammals. This study reports the cloning and functional characterisation of a cDNA encoding human adenylyl cyclase IX (ACIX). The data show that human ACIX is a Ca(2+)/calcineurin-inhibited adenylyl cyclase prominently expressed in vital organs, including brain, heart, and pancreas. ACIX mRNA was detected in several brain regions, including neocortex, hippocampus, striatum, and cerebellum. By in situ hybridisation, ACIX mRNA was localised to pyramidal and granule cells of the hippocampus, indicating that it is expressed predominantly in nerve cells. Further analysis of ACIX mRNA expression revealed two major forms of ACIX mRNA that arose through tissue-specific differential mRNA polyadenylation. Taken together, the data show that (a) human ACIX is under inhibitory control by Ca(2+) through calcineurin, (b) ACIX may be involved in higher brain functions, and (c) post-transcriptional regulation of ACIX gene expression is a species-specific control mechanism that may enhance the versatility of cyclic AMP signalling in humans.

3' Untranslated Regions↗
PubMed1999

Altered surface and cyst epithelium of ovaries removed prophylactically from women with a family history of ovarian cancer.

Despite intensive investigation, the nature of epithelial ovarian cancer precursors remains controversial. Because women with a strong family history of ovarian cancer have a high probability of developing ovarian cancer themselves, ovaries removed prophylactically from such patients provide an opportunity to identify early neoplastic changes. Ovaries removed from 64 consecutive patients undergoing prophylactic oophorectomy and from 30 women with normal ovaries and no known family history of ovarian cancer were examined by light microscopy for a number of histopathologic features and by image cytometry for abnormalities of the cyst and surface epithelium. All analyses were performed without knowledge of the family history. Seven benign, but no tumors of low malignant potential or malignant epithelial tumors were found in the prophylactic oophorectomy group. There were more cortical inclusion cysts in the prophylactically removed than controls ovaries (P = .016), but no other architectural features differed between the two groups. No abnormalities were found in the surface or cyst epithelium in either group by light microscopy. In contrast, image analysis identified differences in the nuclei between the two groups, indicating that those from the surface epithelium of prophylactically removed ovaries were larger and contained more heterogeneously dense chromatin than those of controls, and that nuclei of the cyst epithelium had more irregular outlines. Ovarian epithelium from prophylactically removed ovaries exhibit abnormalities that are only identified by image analysis, and which might represent early preneoplastic changes. Such ovaries may be useful for identifying early molecular changes in ovarian cancer.

Adult↗
PubMed1999

p53, c-erbB, and Ki-67 expression in ovaries removed prophylactically from women with a family history of ovarian cancer.

Prophylactically removed ovaries from 64 women were compared with those from 30 women with no known family history of ovarian cancer for expression of the p53 tumor suppressor protein, the c-erbB-2 oncoprotein, and for the proliferation antigen Ki-67. All analyses were performed without knowledge of the family history. Ki-67 was expressed in rare nuclei in both the surface and cyst epithelial cells, whereas p53 was expressed in rare nuclei only in cyst epithelial cells. Neither the proportion of positive cases nor the intensity of staining differed between groups. c-erbB2 was not expressed in surface or cyst epithelium in any case from either group. Nuclei of granulosa and granulosa lutein cells expressed both Ki-67 and p53. In conclusion, increased expression of p53, c-erbB2, and Ki-67 was not found in the epithelium of prophylactically removed ovaries, suggesting that increased expression occurs later in the development of carcinoma or invasive tumor evolves too quickly to identify expression of these proteins in preinvasive epithelium.

Adult↗
PubMed1999

Preventing neural tube defects. Survey of preconceptional use of folic acid.

OBJECTIVE: To determine the proportion of women who take daily folic acid supplements in the month before conception and to identify factors associated with supplement use. DESIGN: Cross-sectional survey by self-administered questionnaire. SETTING: Tertiary care teaching hospital in Hamilton, Ont. PARTICIPANTS: Four hundred eighty-four (43%) of 1132 women who delivered normal babies between November 1997 and March 1998. MAIN OUTCOME MEASURES: Reports of daily vitamin supplement use in the month before pregnancy and after pregnancy, and having heard or read about the need to take folic acid before pregnancy; sources of information about folic acid; factors associated with preconceptional vitamin use. RESULTS: Thirty-four percent of respondents reported taking vitamins before conception (use ranged from 21% for those with unplanned pregnancies to 40% for those with planned pregnancies); 80% after conception. Of all respondents, 63% were aware of the need for preconceptional folic acid. Key information sources were family doctors and the mass media: the media were more important before conception, doctors after. Being older (30 years or more), having post-secondary education, and having a planned pregnancy were associated with knowing about the benefits of folic acid; knowledge, regular exercise, perceived good health, and planned pregnancy were associated with preconceptional use of vitamins. CONCLUSIONS: Even in this sample of well educated, English-speaking women, only one third took vitamin supplements before conception, which indicates that current educational efforts do not reach most women early enough. A coordinated, multi-pronged strategy that targets and involves physicians and capitalizes on opportunities to work with schools, public health outlets, and the media is needed.

Adolescent↗
PubMed1999

Improving communication between hospital and community physicians. Feasibility study of a handwritten, faxed hospital discharge summary. Discharge Summary Study Group.

OBJECTIVE: To assess the timing, legibility, and completeness of handwritten, faxed hospital discharge summaries as judged by family physicians and to obtain their opinion on the information categories on a standardized discharge summary form. DESIGN: Fax survey of physicians for consecutive patients discharged from hospital over 8 weeks. SETTING: Three wards in a tertiary care teaching hospital. PARTICIPANTS: One hundred two family physicians and general practitioners practising in Hamilton, Ont. MAIN OUTCOME MEASURES: Proportions of summaries that were received, received within 48 hours of discharge, legible, and complete; types of information missing from incomplete summaries; proportion of physicians satisfied with the information categories. RESULTS: Of 271 consecutive patient discharges, 195 (72%) were eligible for study. Among those ineligible, 22 patients (8%) did not have a family doctor identified on their hospital records. Among records that did have a family physician identified, fax numbers were unavailable or unknown for 54 physicians (20%). One hundred two physicians completed 166 discharge summary assessments for a response rate of 85% (166/195). By 3 weeks after discharge, 138 discharge summaries (83%) had been received by patients' family doctors. Among those received, 86% were received within 48 hours of discharge; 92% were legible; and 88% were complete. Hospital doctors' signatures, patients' diagnoses, and follow-up plans were most frequently missing. Ninety-five percent of physicians were satisfied with the information categories included on the standardized form. CONCLUSIONS: Handwritten, faxed hospital discharge summaries were acceptable to family physicians for most patients. Criteria are needed for determining which patients require both handwritten and dictated discharge summaries.

Attitude of Health Personnel↗
PubMed1999

Hypertrophic osteitis of the medial end of the clavicle.

A 9-year-old boy had a spontaneous onset of enlargement of the medial end of the clavicle due to extensive sclerosis and periosteal reaction. There was no clinical or laboratory evidence of infection. Biopsy revealed an inflammatory exudate, and histochemical staining for Langerhans'-cell histiocytosis was negative. Hypertrophic sclerosis causing painful enlargement of the medial end of the clavicle in isolation should be distinguished from condensing osteitis and chronic recurrent multifocal osteomyelitis. An early biopsy to exclude neoplasia is recommended.

Biopsy, Needle↗
PubMed1998

Ca2+/calcineurin-inhibited adenylyl cyclase, highly abundant in forebrain regions, is important for learning and memory.

Activation of cAMP synthesis by intracellular Ca2+ is thought to be the main mode of cAMP generation in the brain. Accordingly, the Ca2+-activated adenylyl cyclases I and VIII are expressed prominently in forebrain neurons. The present study shows that the novel adenylyl cyclase type IX is inhibited by Ca2+ and that this effect is blocked selectively by inhibitors of calcineurin such as FK506 and cyclosporin A. Moreover, adenylyl cyclase IX is inhibited by the same range of intracellular free Ca2+ concentrations that stimulate adenylyl cyclase I. Adenylyl cyclase IX is expressed prominently in the forebrain. Substantial arrays of neurons positive for AC9 mRNA were found in the olfactory lobe, in limbic and neocortical areas, in the striatum, and in the cerebellar system. These data show that the initiation of the cAMP signal by adenylyl cyclase may be controlled by Ca2+/calcineurin and thus provide evidence for a novel mode of tuning the cAMP signal by protein phosphorylation/dephosphorylation cascades.

Adenylyl Cyclase Inhibitors↗
PubMed1998

Ontario hospitals' purchasing practices for hip and knee prostheses: a survey.

OBJECTIVES: To determine the makes, models and prices of the implants provided by Ontario hospitals for hip and knee replacements and the policies and procedures governing purchases. DESIGN: A questionnaire survey of hospitals with telephone follow-up. STUDY POPULATION: Seventy-nine public hospitals in Ontario in which 10 or more hip or knee replacements were carried out in the fiscal year 1993/94. SURVEY RESPONSE: Seventy-six hospitals returned questionnaires (96% response rate), reporting on 4950 primary hip and 5107 primary knee implants. Sixty-two hospitals reported volumes and prices for 19 models used in 2961 hip implants. Information on price but not makes and models was available for 1989 hip implants. Model and price information was missing for 340 hip prostheses. Fifty-seven hospitals identified the models and prices for 3460 knee implants. Twenty-five hospitals provided prices but not specific models names for 1647 knee implants and hybrids. OUTCOME MEASURE: The prices paid for prostheses. RESULTS: The average price of hip implants was Can$2141 (range from Can$650 to Can$3559). The average price for knee implants was Can$2412 (range from Can$1178 to Can$3777). The averages and ranges were about the same for specified and unspecified models and hybrids. The variations were unrelated to hospital policies about the numbers of procedures to be provided or the procedures for making purchases from suppliers. CONCLUSIONS: Savings of Can$13.7 million could have been made in Ontario during the fiscal year 1993/94 had the lowest prices been paid for the implants. Although it may be neither desirable nor possible to use the least expensive model and price in every hospital, the potential for cost reductions in the purchase of implants is substantial.

Cost Savings↗
PubMed1996

Appropriateness of primary total hip and knee replacements in regions of Ontario with high and low utilization rates.

OBJECTIVE: To compare the appropriateness of case selection for primary hip and knee replacements between two regions in Ontario: one with a high population-based utilization rate and one with a low rate. DESIGN: Random audit of medical records sampled from hospital discharge abstracts, with subsequent implicit and explicit criteria-based assessments of the appropriateness of surgery. STUDY POPULATION: People aged 60 years or over who underwent elective, single-joint, non-fracture-related, primary hip or knee replacement between Apr. 1, 1992, and Mar. 31, 1993, at one of seven hospitals in a high-rate region (comprising Brant, Huron and Oxford countries) or one of eight hospitals in a low-rate region (comprising the cities of Scarborough and Toronto). INTERVENTIONS: Structured review of hospital medical records, with additional review of information from surgeons and family physicians' office charts if necessary. Three physicians reviewed patient data and rated the preoperative pain level and functional status of patients, with agreement among at least two reviewers. The proportion of inappropriate cases was then assessed according to explicit criteria defined by a multidisciplinary panel using the delphi process. Profiles of each case were also subjected to independent implicit review by two rheumatologists and two orthopedic surgeons. OUTCOME MEASURES: Proportion of joint replacements deemed inappropriate in the high- and low-rate regions according to either the explicit criteria or the implicit review, as well as preoperative pain levels and functional status of patients in the high- and low-rate regions. RESULTS: Hip replacements were more common among patients sampled in the low-rate region than among those in the high-rate region (57.3% v. 39.3%; p < 0.002), although the patients' baseline characteristics, including severity of preoperative pain and dysfunction, were otherwise similar between the regions. Inappropriate surgery, determined by explicit criteria, was equally uncommon in the two regions (6.4% and 6.1%). On implicit review, the two rheumatologists rated fewer cases as appropriate than did the two orthopedic surgeons (63.0% v. 80.0%; p < 0.001); however, the proportion of cases rated as inappropriate by the subspecialists was similar in the high- and low-rate regions (11.4% and 11.0%, respectively, by the rheumatologists, and 6.3% and 10.4%, respectively, by the orthopedic surgeons). CONCLUSIONS: Patients selected for primary hip or knee replacement are similar in the high- and low-rate regions of Ontario. Inappropriate use of this procedure does not account for the high rate of surgery in some areas. Further studies will be required to determine which other factors account for the regional variations in the utilization rates and whether there is underservicing in low-rate areas.

Chi-Square Distribution↗
PubMed1996

Cholesterol policy and the primary prevention of coronary disease: reflections on clinical and population strategies.

Despite billions of dollars spent on targeted and population-wide strategies aimed at reducing human consumption of saturated fat and cholesterol, aspects of the diet-heart connection remain a source of debate. At least part of the uncertainty arises from a growing appreciation that the relationship between dietary habits, serum lipids, and atherosclerosis is more complex than was previously thought. While we wait for answers from clinical and basic research, what is to be done? This review examines evidence about clinical policies and population strategies for the primary prevention of coronary disease, with specific reference to diet and dyslipidemias. It also summarizes some current policies and offers conclusions about broad directions for further policy development.

Attitude to Health↗