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J C Le Riche

Publications and source records attributed to J C Le Riche.

8 recordsLinked to original sources
PubMed1999

The comet assay in clinical practice.

The comet assay is a single-cell gel electrophoresis technique that measures DNA damage in individual cells. Since radiation produces 3-4 times more DNA damage in well-oxygenated cells compared with hypoxic cells, this assay can quantify the fraction of radiation-resistant hypoxic cells found in many solid tumours. This paper summarizes our results with 73 accessible metastatic tumours irradiated with palliative intent. Hypoxic fractions ranged from 0.0 to 0.67 with a mean of 0.15; 62% of these advanced tumours showed a hypoxic fraction > 0.05. Comparisons between two sequential aspirates in 33 tumours gave a slope of 0.92 (r2 = 0.88), suggesting that a single aspirate is generally representative of the tumour. A limitation, however, is that the hypoxic fraction could not be measured in clinical samples given a conventional dose of 2 Gy.

Animals↗
PubMed1992

Invasive cancer of the cervix in British Columbia: a review of the demography and screening histories of 437 cases seen from 1985-1988.

The charts of 437 patients with newly diagnosed invasive cervical cancer seen in British Columbia during 1985-1988 were reviewed to determine the age at diagnosis, stage of disease, and histology of the lesions. The patient's immigration status and country of birth were also examined. Two hundred forty-two patients (55%) were age 50 or over and 149 (34%) had preclinical stage IB disease. One hundred seventy of these patients (39%) had never had a cytologic examination before presenting with clinical symptoms, and 45 additional patients had not had cytology for 5 or more years before presenting with invasive disease; thus, a total of 215 cases (49%) fell into the category of "no cytology or cytology longer than 5 years ago." All negative smears were reviewed and in 39 patients (15%) having previous cytology, abnormal cells had been missed or undercalled. Native Indian women made up 10% of the cases of invasive carcinoma, a disproportionately large number as they represent only 2% of the British Columbian population. Of the 27 Native Indian patients in this series, 16 (59%) had never had a cytologic examination. Eighty-five (30%) of 276 women born in Canada had never had a cytologic examination, compared with 34 (71%) of 48 immigrants resident in the country for fewer than 10 years. Twenty-four patients were over the age of 60 with a history of negative Papanicolaou smears. We conclude that, if further gains are to be made in the reduction of death rates from invasive cervical carcinoma, new means must be found to encourage women to participate in Papanicolaou smear screening programs. In particular, special efforts must be made to attract specific groups, such as the Native Indian population and older recent immigrants.

British Columbia↗
PubMed1992

The use of sequential fine-needle aspiration biopsy with flow cytometry to monitor radiation induced changes in breast carcinoma.

Thirteen patients with locally advanced or recurrent breast carcinoma were monitored during radiation therapy by multiple, sequential, fine-needle aspiration biopsies (FNAB) with flow cytometry. The material was analyzed for qualitative cytomorphological evidence of radiation effect and for DNA content and cell cycle alterations. DNA ploidy was not affected by the radiation therapy, although the aneuploid tumors showed an increased frequency of cell cycle alterations. The most common change seen was an increase in S-G2M (58%). Other changes included a decrease in the proliferative/growth fraction (17%) and no significant redistribution of cells (25%). There was a relationship between the initial proliferative activity of the tumors and the type of cell cycle change which occurred. Flow cytometric analysis was a better predictor of early clinical response than was cytomorphological assessment. Sequential FNAB with flow cytometry is an effective method of monitoring the response of breast cancer to radiation therapy.

Biopsy, Needle↗
PubMed1992

Determination of DNA ploidy in archival tissue from non-Hodgkin's lymphoma using flow and image cytometry.

Paraffin-embedded tissue from a series of 40 cases of diffuse, large cell lymphoma was analyzed by both flow and image cytometry to compare the ability of these techniques to detect DNA aneuploid populations. Image cytometry (ICM) was performed both on nuclear suspensions and tissue sections. Twenty cases (50%) were non-diploid by at least one method of analysis. Twenty-five percent of the cases were aneuploid by flow cytometry (FCM) alone. The majority of these cases were near-diploid tumors which could not be resolved by ICM. Peri-tetraploid peaks were identified by ICM of tissue sections alone in 15% of the cases. There was an apparent loss of these peri-tetraploid cells during the preparation of the nuclear suspensions. The remaining cases showed a good correlation between all three methods in the determination of DNA ploidy. Flow and image cytometry are complimentary techniques when applied to archival tissue, however aneuploid populations may be missed if ICM is not performed on tissue sections.

Aneuploidy↗
PubMed1988

Organisation and results of the cervical cytology screening programme in British Columbia, 1955-85.

A screening programme to detect preinvasive carcinoma of the cervix was started in British Columbia in 1949. Since 1970 the number of women who have been screened at least once has been maintained at about 85% of the population at risk. More than 500,000 cervical smears are being examined each year in the central laboratory. There has been an appreciable increase in the number of cases and rates of carcinoma in situ seen since 1970, particularly in women between 20 and 30 years of age. Since the programme started over 26,000 cases of squamous carcinoma in situ have been detected and treated. The incidence of clinically invasive squamous carcinoma of the cervix has fallen by 78% during the period under review, and mortality from squamous carcinoma of the cervix has fallen by 72%. A colposcopy programme, introduced throughout British Columbia over the past 12 years, has been important in reducing the problems of managing preinvasive lesions, particularly in younger women. It is concluded that the reduction in morbidity and mortality from invasive squamous cancer of the cervix in British Columbia over the past 30 years is directly attributable to the province wide screening programme and that a large potential increase in invasive cervical cancer rates among younger women is being prevented.

Adolescent↗
PubMed1987

Multiple gingival metastases from angiosarcoma of the breast.

Metastases to the jaws and oral soft tissue occur rarely. Such metastases may result in the presenting symptoms and signs of malignant disease or may develop during the course of a previously diagnosed malignant condition. A case of multiple gingival metastases in a patient with angiosarcoma of the breast is reported.

Adult↗
PubMedDate not supplied

A comprehensive internal quality control system for a large cytology laboratory.

The British Columbia Cervical Cytology Program is operated through the Central Laboratory at the Cancer Control Agency in Vancouver and processes all of the gynecologic Papanicolaou smears collected by 3,200 physicians throughout the province of British Columbia. The laboratory receives approximately 2,400 smears per day, and the program currently processes in excess of 500,000 smears annually. This article describes the methods that have been developed for ensuring that adequate quality control is present in the screening and interpretation of half a million smears per year, both at the cytotechnologist and at the cytopathologist level. The results of the quality control program, which was considerably modified in 1985, are also presented. The modified program shows a significant improvement in the number of undercalled and overcalled cases detected in two comparable six-month periods.

British Columbia↗