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Biomedical subjects

J Grace

Publications and source records attributed to J Grace.

At least 73 records · Page 4Linked to original sources
PubMed1990

Comparison of flow cytometry and retrospectively applied static cytometry on lymphoid tissue.

Twenty cases of non-Hodgkin's malignant lymphoma were examined using both flow cytometry (FCM) and static cytometry (SCM) DNA analysis to detect aneuploidic cell populations. FCM was performed on fresh cell suspensions whilst SCM was performed retrospectively on formalin-fixed, paraffin-embedded samples of the same tissue. A total of 34 aneuploidic cell lines were detected by FCM compared to a total of 41 detected by SCM. Of the 20 cases 14 showed DNA indexes within 10% of each other for each method, indicating a reasonable degree of comparability between the two methods. Of the 6 cases which did not show comparable DNA indexes, 2 displayed similar cell lines for both methods, but the major abnormal cell populations were of different ploidy by SCM as compared to FCM. A qualitative comparison is thus possible between these two cases. The results suggest that retrospectively applied SCM ploidy analysis of lymphoid tissue is comparable to FCM on fresh tissue samples and can thus be used in retrospective studies of both prognostic and diagnostic significance.

Cytological Techniques↗
PubMed1989

Cytogenetic abnormalities in benign lymphoid hyperplasia: a dual-parameter study using chromosome analysis and flow cytometry.

This is a prospective study of lymphoid tissue showing benign reactive hyperplasia (18 lymph nodes and 2 tonsils), using cytogenetic analysis of cells stimulated with T- or B-cell mitogens. The reason for this study was the detection of an abnormal chromosomal population in cells from an enlarged lymph node excised from a 7-year-old female who on further investigation was found to be clinically well and after one year's close follow-up had not developed any further signs or symptoms of malignancy. In addition, DNA content was measured by flow cytometry (FCM) on fresh cell suspensions in 17 cases and fixed cell suspensions in 3 cases. Structural and numerical clonal chromosome abnormalities were found in 9 of the 20 samples, but no common specific defect was identified. FCM showed an abnormal DNA content in 10 of the 20 samples studied; 3 of these showed clonal chromosome abnormalities. Surface membrane immunoglobulin studies were carried out on 15 of the 20 samples using cell suspensions and frozen tissue sections. In 5 of the 15 cases, monoclonal surface immunoglobulin was detected. There was no direct correlation between the surface membrane immunoglobulin studies and the chromosome and FCM analyses. We conclude that aneuploidy is a common feature in reactive lymphoid tissue, but both cytogenetics and FCM are needed to identify it.

Aneuploidy↗
PubMed1989

Ultrasound emission after cycles of water stress in Picea abies.

The relationships among rate of ultrasound acoustic emission (AE), xylem water potential and transpiration rate were investigated in 5-year-old potted saplings of Picea abies Karst. after cycles of water stress. Water-stressed plants displayed minimum xylem water potentials of -3.9 MPa, near-zero transpiration rates and up to 45 AE counts per minute. After rewatering, water-stressed plants no longer produced AEs. Well-watered control plants produced only a small number of ultrasonic AEs. After three cycles of water stress (lasting 24 days in total), it was estimated that about two-thirds of the functional tracheids were embolized. The concomitant reduction in hydraulic conductance was about 70%.

Journal Article↗
PubMed1989

Comparison of flow cytometric data obtained using fresh and paraffin-embedded lymphoid tissue.

Flow cytometric (FCM) DNA analysis was carried out on 24 lymph nodes: 13 from benign reactive hyperplasias and 11 from non-Hodgkin's lymphomas. FCM was performed on two types of samples: (1) fresh cell suspensions and (2) suspensions prepared from formalin-fixed, paraffin-embedded sections. FCM of fresh samples detected aneuploidy in 23 of the 24 cases while FCM of paraffin-embedded samples detected aneuploidy in only 6 of the 24 cases. Those six cases were lymphomas considered histologically as having a poor prognosis. Only one case, a lymphoma, was euploid with both methods. The coefficients of variance determined in each case for both methods were found to be within "normal ranges," but were greater in the paraffin-embedded specimens. The results suggest that FCM DNA analysis of formalin-fixed, paraffin-embedded sections does not have as great a resolution capacity as does analysis of fresh cell suspensions, since the former failed to detect cell populations that had a small degree of aneuploidy (close to the 2n population).

DNA↗
PubMed1988

DNA ploidy in thin melanoma.

DNA ploidy in benign nevi (BN), thin non-metastasizing melanomas (TNM) and thin metastasizing melanomas (TMM) was investigated using an image analyser to determine whether characteristics such as nuclear area (NA) and nuclear integrated optical density (IOD) could be used to distinguish between these lesions. NA measurements showed significant differences between samples of nevus cells and melanoma cells and nuclear IOD differences were significant between TNM and TMM samples. Differences in NA and nuclear IOD were detected across the three groups (BN, TNM and TMM) but the large variability within samples and within groups indicate further studies would be necessary to determine the usefulness of these results in terms of the rate of correct group classification of a single sample for diagnostic purposes.

Adolescent↗
PubMed1988

Measuring general practitioner referrals: patient, workload and list size effects.

Individual general practitioners are known to vary widely in the number of patients they refer to hospital outpatient departments; indeed there is increasing concern that the 'high' referrers use a disproportionate quantity of National Health Service resources. Data from a one-week survey of referrals by 122 general practitioners in one health district showed that a different age-sex mix of patients consulting individual general practitioners might account for about one quarter of his or her referrals. The results also showed that different referral rates, calculated by using either workload or list size denominators, identified markedly different groups of high referrers. These different methods of measurement are discussed, and on practical grounds a referral rate based on actual referrals divided by mean practice list size is suggested for future comparisons.

Data Collection↗
PubMed1988

Temperature as a determinant of plant productivity.

Quite small variations in temperature such as those that exist between the north and south of Britain, or on a local scale between north and south aspects of a hill, may cause large variations in plant productivity. An attempt is made to assess the effect of a 1 degree C increase in the mean temperature of the growing season by using published data from various sources. The conclusion reached is that a 1 degree C increase in a north temperate climate may be expected to increase plant productivity by about 10%, providing that other factors like water or nutrients do not become limiting. But, for annual crops, a negative effect of temperature has sometimes been observed. This may be because temperature speeds up the development of the crop and thus reduces the duration of photosynthesis. In the natural environment variations in solar radiation and wind speed may often exert an effect on growth because they influence the energy balance, altering the temperature of meristems and other plant tissues in subtle ways which have a significant impact on the pattern of carbon utilization. A more precise understanding of the relationship between growth and weather variables is unlikely to be achieved unless models are developed which enable integration of component processes of growth with what is known about the spatial and temporal variation in the weather variables.

Environment↗
PubMed1987

Micropropagation of mature Calabrian pine (Pinus brutia Ten.) from fascicular buds.

Dormant meristems of fascicles explanted from 10-year-old, field-grown trees of Pinus brutia Ten. were cultured in vitro. Browning of cultured fascicles was reduced by including 150 mg l(-1) sodium diethyldithiocarbamate (SDD) in a cytokinin-containing medium. The stage of development of fascicles when placed in culture affected both shoot-bud production and the degree of browning. Only fascicles at an advanced stage of development had a high rate of shoot-bud production. Fascicles cultured for 6 weeks in initiation medium containing 150 mg l(-1) SDD and then for 4 weeks in initiation medium containing 1 mg l(-1) insoluble polyvinylpolypyrrolidone showed the highest rate (23%) of shoot-bud development and the lowest rate (15%) of browning. Elongation of activated shoot buds was considerably enhanced by reducing the concentration of cytokinin in the culture medium. Only shoots >/= 20 mm in height were capable of producing further crops of buds and shoots. When treated with a combination of auxin and cytokinin, only 16% of the elongated shoots produced roots.

Journal Article↗
PubMed1987

Immunohistological evaluation of MHC class I and II antigen expression on nevi and melanoma: relation to biology of melanoma.

MHC antigen expression on 20 nevi, and 35 primary and 95 metastatic melanomas was studied by immunoperoxidase techniques using monoclonal antibodies to identify the antigens on frozen tissue sections. DR antigens were not detected on nevi but were detected on 71% of primary melanomas and 56% of metastases, suggesting that this antigen may be a useful marker of malignant transformation of nevi. Expression of class II antigen could not be related to other prognostic histological features of primary melanoma such as tumour thickness, but comparison of the common phenotypes of primary and metastatic melanoma suggested that expression of DR antigens alone in the absence of DP, DQ and ABC antigens may be an indicator of metastatic potential. Class I (HLA-A,B,C) antigens were also expressed infrequently on nevi but were detected on 43% of primary melanomas and 34% of metastases. HLA-A,B,C expression was inversely related to thickness of the primary melanoma. This as well as the lower expression of class I antigens on metastases, may indicate that growth and spread of melanoma may be inhibited by MHC (class I) dependent cytotoxic T cell responses. Expression of class I MHC antigens was unrelated to class II antigens. Expression of DR was more common than DP or DQ, but the latter with one exception, were not expressed in the absence of DR antigens. Significant differences were not found in MHC antigen expression on metastases in lymph nodes compared to those in subcutaneous sites, but further studies are needed to determine whether such differences may exist between metastases in other visceral sites.

Antibodies, Monoclonal↗
PubMed1986

A preliminary report on the suitability of sheep epidermal squamous cell carcinoma as a solid tumor model in the evaluation of intra-arterial methotrexate administration.

A preliminary study was undertaken to assess the sensitivity of sheep epidermal squamous cell carcinoma, in the head and neck region, to intra-arterial (IA) methotrexate (MTX) infusion. There was an objective tumor response (40-56% regression) in all three IA-infused sheep, whereas tumor progression was observed in all three animals treated intravenously (IV). Regional and systemic side effects were negligible in all cases. Technically, IA drug infusion in the sheep was an improvement on previous small animal models, with no problems related to arterial catheter insertion, blockage, or dislodgement, and tolerable infusion times being of markedly longer duration. The histological differentiation of moderately differentiated stage II lesions improved during therapy irrespective of clinical response, whilst the histology of well-differentiated stage III and IV tumors remained unchanged. Tumor cell cycle stage and ploidy characteristics, as determined by flow cytometric DNA analysis, were little affected by either mode of drug administration. It is concluded that sheep epidermal carcinoma is responsive to IA MTX, and that this animal model is the most appropriate yet utilised to study the comparative effects of IA and IV chemotherapy in the head and neck region.

Animals↗
PubMed1986

Ploidy and proliferative characteristics of sheep epidermal squamous cell carcinoma determined by flow cytometric DNA analysis.

Multiple biopsies from each of 22 primary sheep epidermal squamous cell carcinomas were analysed by flow cytometry to determine the G0/G1 modal DNA content ("ploidy") and cell cycle characteristics within each tumour. Ten of 12 tumours where aneuploidy was present demonstrated uniform intra-tumour aneuploid populations regardless of the site of biopsy. Increasing tumour volume (from stage I/II to stage III/IV lesions) was associated with increased histological variability and ultimate heterogeneity of G0/G1 DNA content, whilst the mean numbers of S phase cells decreased. These features were consistent with the effects of variable tissue hypoxia seen with changes in effective vascularity in developing tumours. Decreasing histological differentiation was associated with an increase in numbers of cells synthesising DNA within 44 biopsies with measurable S phase, and, in stage I/II biopsies, correlated with an increased incidence of aneuploidy.

Animals↗
PubMed1986

Harvey-ras oncogene restriction fragment alleles in familial melanoma kindreds.

Unique and uncommon BamHI allelic restriction fragments of the Ha-ras locus have been reported in the genomes of patients with cancer and of three affected members of a familial melanoma kindred (Krontiris et al., 1986). Analysis of the BamHI and Msp/HpaII restriction fragments of peripheral blood leucocyte DNA from the members of two families with hereditary melanoma (HM)/familial dysplastic naevus syndrome (DNS) revealed that the only Ha-ras allele common to four affected members of one kindred and two from a second kindred, was the 6.7kb allele which is found in 66% of the normal population. This allele was found equally in affected and non-affected family members, and in one affected case was inherited from an unaffected homozygous parent. It was absent in two affected sisters in a third kindred. In the first kindred the karyotype of all three melanoma sufferers was 46XX 9qh+, while six unaffected members had a normal karyotype. BamHI polymorphism of the Ha-ras gene does not identify the affected members in the HM/DNS families studied.

Alleles↗
PubMed1985

Current research on immunopathology of melanoma: analysis of lymphocyte populations in relation to antigen expression and histological features of melanoma.

Immunoperoxidase localization of monoclonal antibodies in sections of melanoma has been used to identify histological features which may be of prognostic importance in melanoma, in particular whether certain structures on melanoma cells may determine the degree and nature of lymphoid infiltrates and whether these may be related to prognosis. Monoclonal antibodies to lymphocyte subpopulations were used to identify and quantitate lymphoid infiltrates in 15 primary melanomas and 8 cutaneous metastases. These were correlated with histological features identified in routine sections. There was a wide variation in the numbers of mononuclear cells associated with both primary and metastatic melanoma. T cells and to a lesser extent macrophages accounted for the majority of the cells, B cells and natural killer (NK) cells for only 2% of the infiltrates. The Leu 3a (helper) T cell subpopulation predominated in primary tumours, OKT8 positive (suppressor/cytotoxic) cells in metastases. Infiltrates in which OKT8 cells predominated were associated with ulceration, a high mitotic rate and thick primary tumours. The converse applied to Leu 3a infiltrates. Infiltrates with a high proportion of Leu 3a positive cells tended to be associated with Thy-1 positive, DR antigen negative tumours. Thy-1 antigens were predominantly expressed on primary tumours and rarely on metastases whereas the converse applied to expression of the acute lymphoblastic leukemia antigen (CALLA) on melanoma cells. These findings suggest that certain melanoma antigens may be related to the nature of the lymphoid infiltrate associated with melanoma and possibly with the behaviour of the tumour in the host. They further suggest that identification of cell surface structures and lymphoid infiltrates by these techniques may be a valuable extension of routine histopathological assessment of prognosis in melanoma.

Antibodies, Monoclonal↗
PubMed1983

Expression of Thy-1 antigen on human melanoma cells.

The expression of Thy-1 was examined on fresh frozen sections of melanoma and control skin lesions using a monoclonal antibody to Thy-1 and immunoperoxidase-labelled second antibodies. Thy-1 was detected on 12 of 19 primary melanomas but on only 1 of 23 melanoma metastases in lymph nodes, skin or brain. Expression of Thy-1 did not appear related to other known histological features of primary melanoma. Thy-1 was also expressed on 2 of 7 naevi but not on normal melanocytes or carcinoma of squamous cells, basal cells and sweat glands of the skin. Some lymphocytes below primary melanomas were Thy-1 positive. These results suggest that Thy-1 may be a marker of melanocytes at certain stages of differentiation analogous to its expression on cell lineages in the haemopoietic system. The relative paucity of Thy-1 on metastases may indicate that its expression on melanoma cells has prognostic significance for behaviour of the tumour in its host.

Adult↗