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Biomedical subjects

J MacKay

Publications and source records attributed to J MacKay.

17 recordsLinked to original sources
PubMed2004

Gene expression during formation of earlywood and latewood in loblolly pine: expression profiles of 350 genes.

The natural variability of wood formation in trees affords opportunities to correlate transcript profiles with the resulting wood properties. We have used cDNA microarrays to study transcript abundance in developing secondary xylem of loblolly pine (Pinus taeda) over a growing season. The cDNAs were selected from a collection of 75 000 ESTs that have been sequenced and annotated (http://web.ahc.umn.edu/biodata/nsfpine/). Cell wall thickness and climatic data were related to earlywood and latewood formation at different time points during the growing season. Seventy-one ESTs showed preferential expression in earlywood or latewood, including 23 genes with no significant similarity to genes in GenBank. Seven genes involved in lignin synthesis were preferentially expressed in latewood. The studies have provided initial insights into the variation of expression patterns of some of the genes related to the wood formation process.

Expressed Sequence Tags↗
PubMed2001

Screening with breast ultrasound in a population at moderate risk due to family history.

OBJECTIVE: To perform a pilot study to compare ultrasound and mammographic screening with particular respect to specificity, in a cohort of women at moderate family history risk of breast cancer. MATERIAL AND METHODS: High resolution ultrasound of both breasts was undertaken in 149 women at moderate risk of breast cancer who were referred for mammographic screening. The two tests were read blind to the other. Core biopsy was undertaken for solid lesions found on ultrasound. RESULTS: 149 Patients, mean age 42.15 years, were screened with bilateral ultrasound. 90 Examinations were normal. 46 Women had cysts, two had lesions previously biopsied and found to be benign, and one had a lymph node. 10 Focal solid lesions were biopsied on account of their ultrasound findings, 6.7% (95% confidence intervals (95% CIs) 2.7% to 10.7%). All but one of the 149 mammograms were normal. In this case both mammography and ultrasound showed a focal solid lesion that at core biopsy was found to be a fibroadenoma. Histology showed seven fibroadenomata, two areas of fibrocystic change, and one adenoid cystic carcinoma. Positive predictive value for biopsy was 10%. Mean follow up was 13.7 months. There was one interval cancer. CONCLUSION: Screening with breast ultrasound, in a cohort of women at moderate risk of breast cancer due to family history, has an acceptable biopsy rate. Screening with ultrasound and mammography in patients with an increased risk of breast cancer may be beneficial and a randomised study to examine issues of acceptability, reproducibility, and cost effectiveness is apt.

Adult↗
PubMed1996

High-dose chemotherapy supported by peripheral blood progenitor cells in poor prognosis metastatic breast cancer--phase I/II study. Edinburgh Breast Group.

Current treatments for metastatic breast cancer are not associated with significant survival benefits despite response rates of over 50%. High-dose therapy with autologous bone marrow transplantation (ABMT) has been investigated, particularly in North America, and prolonged survival in up to 25% of women has been reported, but with a significant treatment-related mortality. However, in patients with haematological malignancies undergoing autologous transplantation, haematopoietic reconstruction is significantly quicker and mortality lower than with ABMT, when peripheral blood progenitor cells (PBPCs) are used. In 32 women with metastatic breast cancer, we investigated the feasibility of PBPC mobilisation with high-dose cyclophosphamide and granulocyte colony-stimulating factor (G-CSF) after 12 weeks' infusional induction chemotherapy and the subsequent efficacy of the haematopoietic reconstitution after conditioning with melphalan and either etoposide or thiotepa. PBPC mobilisation was successful in 28/32 (88%) patients, and there was a rapid post-transplantation haematopoietic recovery: median time to neutrophils > 0.5 x 10(9) l-1 was 14 days and to platelets > 20 x 10(9) l-1 was 10 days. There was no procedure-related mortality, and the major morbidity was mucositis (WHO grade 3-4) in 18/32 patients (56%). In a patient group of which the majority had very poor prognostic features, the median survival from start of induction chemotherapy was 15 months. Thus, PBPC mobilisation and support of high-dose chemotherapy is feasible after infusional induction chemotherapy for patients with metastatic breast cancer, although the optimum drug combination has not yet been determined.

Adult↗
PubMed1995

The effects of antihypertensive therapy on carotid vascular structure in man.

OBJECTIVE: An increased carotid intima-media thickness (IMT) has been found to be associated with a number of cardiovascular risk factors such as age, hypertension, cigarette smoking, hypercholesterolaemia and left ventricular hypertrophy. Our objective was to assess whether carotid intima-media thickness in hypertensive patients could be reduced by antihypertensive therapy. METHODS: 13 hypertensive patients, 10 previously untreated, were examined using carotid ultrasonography and echocardiography at baseline and then at 8 weeks and 39 weeks after commencement of antihypertensive therapy with ramipril and the second-line addition of felodipine. RESULTS: By the end of the study significant regression of IMT (0.1(0.05-0.16) mm, F-value 10.2, P < 0.01) and left ventricular mass index had occurred (25(10.7-39.3) g/m2, F-value 9.7, P < 0.01). The reduction in IMT was significantly related to the reduction in mean arterial pressure, r = 0.55, P = 0.05). CONCLUSION: Antihypertensive therapy with ramipril and felodipine causes regression of IMT in hypertensive patients, probably chiefly through blood pressure reduction. Large prospective studies are required to assess whether a reduction in IMT results in a reduction in morbidity and mortality.

Adult↗
PubMed1995

Home care for the postoperative cataract patient.

The traditional collaborative practice model sustained a negative impact when cataract surgery became an outpatient procedure. Discharging postoperative cataract patients to self care a few hours after surgery, allows limited time to appropriately plan for rehabilitative needs. Home ophthalmic nursing care restores the collaborative practice model while addressing ophthalmic conditions. Complications of cataract surgery are a reality and range from minor to catastrophic. The nurse is able to assess the postoperative patient, to collaborate with the ophthalmologist and to intervene expeditiously. The ophthalmic registered home care nurse acts as the vital link between the ophthalmologist and the patient.

Cataract Extraction↗
PubMed1994

A parametric model for cluster correlated categorical data.

A fully parametric copula model for symmetric dependent clustered categorical data is discussed. The model accommodates any marginal regression models of interest and admits a broad range of within-cluster association. The form of the distribution is independent of cluster size and may be used to model data with varying cluster sizes. The model contains an association parameter that is estimated from the data to give a measure of strength of the within-cluster association and also a test of independence. Two examples are given to illustrate methods.

Analysis of Variance↗
PubMed1989

Variations in fluoroscopic and spot film techniques during extracorporeal shock wave lithotripsy.

The radiation techniques of different operators who performed extracorporeal shock wave lithotripsy of the kidney were evaluated retrospectively. The study was limited to 9 operators who each performed more than 100 procedures on the Dornier lithotriptor. The average fluoroscopic time and number of video spot films per procedure for all operators were 4.1 minutes and 6.5, respectively. However, the average fluoroscopic time per operator varied from 1.4 to 7.6 minutes and the average number of video spot films per operator varied from 3 to 13. The results illustrate the need for some operators to reduce fluoroscopic time and video spot filming.

Fluoroscopy↗
PubMed1981

Bacterial fouling of a hospital closed-loop cooling system by Pseudomonas sp.

During the summer of 1979 the air-conditioning system at a hospital in Boston deteriorated, and this led to total failure of some chilling units. Patient care and operating-room areas were affected. Investigation of the problem ruled out mechanical and electrical causes, but revealed a strain of Pseudomonas sp. biofouling heat transfer tubes of the closed chilled water system. The pseudomonads apparently were stimulated to grow by low concentrations of ethylene glycol antifreeze. The proximate source of these organisms was an expansion tank located in a 33 degrees C environment. The organisms probably originated from the potable water supply of the hospital. Fouling was eventually cleaned by prolonged and expensive treatments of the closed chilled water system. Pseudomonas sp. is frequently isolated from hospital-acquired infections at our institution (Beth Israel Hospital, Boston, Mass.); however, our studies with fluorescent dye tracers indicated that organisms were prohibited from entering patient areas via contaminated water from the chillers. Microbiologists must become cognizant of seemingly unimportant microbial environments within hospitals that may indirectly contribute to hospital-acquired infections.

Air Conditioning↗
PubMedDate not supplied

BRCA1 gene testing for breast and ovarian cancer in one family.

Most breast cancer is multifactorial in origin, but dominantly inherited genes are implicated in the development of approximately 5-10% of breast cancer as a whole. The identification of the BRCA1 gene, thought to account for 2% of all breast cancer and be present in almost all families affected by breast and ovarian cancer, makes testing for susceptibility to breast and ovarian cancer possible for the few families in which researchers have identified a gene mutation. Genetic counselling, by medically qualified geneticists, is available for people with rare genetic conditions caused by gene mutations. In this article, the authors describe their first experience of BRCA1 gene testing in 23 family members. They identify a unique role within a new specialty, cancer genetics, for specialist nurse practitioners in genetic testing and counselling.

Adolescent↗