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Biomedical subjects

D M Barnes

Publications and source records attributed to D M Barnes.

At least 37 records · Page 2Linked to original sources
PubMed2000

Cell cycle proteins do not predict outcome in grade I infiltrating ductal carcinoma of the breast.

Infiltrating ductal mammary carcinomas are histologically graded according to their extent of differentiation. Well-differentiated, grade I, tumours have low proliferative activity, usually form tubules and exhibit little nuclear pleomorphism. Despite an apparently reassuring morphology, 10-15% of grade I ductal carcinomas metastasize, albeit after a prolonged period. Recent evidence supports the view that evolution to higher grade malignancies occurs rarely and that grade I tumours are biologically distinct from grade III tumours. We have examined a series of 148 grade I ductal carcinomas in order to ascertain whether information about the level of expression of cyclin D1, p27, p53, oestrogen receptor status (ER) or proliferative activity could be used to identify those patients with a poor outcome. The majority of tumours expressed high levels of cyclin D1, p27 and ER, low levels of p53 and had low Ki-67 expression and mitotic counts. Cyclin D1, p27 and ER expression were all significantly correlated with each other but not with p53 (cyclin D1 correlation with ER, p = 0.01; cyclin D1 correlation with p27 and ER correlation with p27 both p < 0.0001). Cyclin D1 and ER were also both correlated with Ki-67 (p = 0.01 and p < 0.0001) but not with mitotic count. Our results suggest that cyclin D1, ER and p27 are all markers of well-differentiated tumours and that their detection is related to proliferative activity in a manner reflecting their functional role within the normal cell cycle. However, none of the proteins or markers of proliferative activity were sensitive enough to predict which patients were likely to have a poor outcome.

Adult↗
PubMed2000

Multiple tissue core arrays in histopathology research: a validation study.

The use of multiple tissue arrays allows the examination of large cohorts of tumour tissue with economies of material and technical resources. It also permits the direct comparison of tissues on the same slide. In the present study, a series of 157 breast cancers was labelled with antibodies which recognize oestrogen (ER) and progesterone (PR) receptors and the staining obtained on whole tissue sections was compared with that from a series of multicore arrays. A highly significant association was found between the staining scores (0-7) obtained from the individual tissue sections and from the multicore arrays, although there was some discordance between the receptor status (positive/negative) of the whole section and the tissue core in 5% of cases for ER and in 6.5% of cases for PR. Multiple tissue cores represent an attractive way of dealing with large cohorts of tumours for research studies, because of the significant reduction in reagents and technical time required and the overall speed with which a study can be completed. A proportion of individual tissue cores were not representative of the diagnostic section, which limits the value of multicore arrays as a tool for patient management. However, the technique provides an efficient way of assessing the potential predictive value of novel proteins in different tumour types and in large cohorts.

Biomarkers, Tumor↗
PubMed2000

Improving the detection of p53 mutations in breast cancer by use of the FASAY, a functional assay.

The aim of this investigation was to examine the ability of the yeast-based functional assay, the functional analysis for the separation of alleles in yeast (FASAY), to detect p53 mutations in breast cancers when compared with immunohistochemistry and automated sequencing of the whole p53 gene (exons 1-11). To achieve this, all three methods were carried out on a cohort of aggressive breast tumors. In those tumors, in which the FASAY analysis indicated the presence of a mutation, cDNA was extracted from red yeast colonies and was sequenced to identify the base change in the p53 gene. The FASAY detected all 24 mutations found in the series of 48 tumors, whereas initial automated sequencing of genomic DNA detected 18/24 mutations. A second round of automated sequencing carried out using an independent source of genomic DNA detected mutations in 3 of the 6 tumors that originally appeared to lack a mutation in genomic DNA. All but 1 of the mutations originally missed by sequencing of genomic DNA were point mutations. Five mutations in this series (21%) were outside the commonly investigated exons 5-8, reinforcing the need to extend sequencing beyond this region. Of 24 tumors, 14 had strong immunohistochemical staining, and all 14 had p53 mutations; the majority of mutations missed by immunohistochemistry produced a truncated protein. Strong staining was not seen in tumors lacking a p53 mutation. The FASAY proved to be a rapid, reliable, and effective method for identifying those breast tumors harboring p53 mutations.

Alleles↗
PubMed2000

The value of rapid functional assays of germline p53 status in LFS and LFL families.

We have tested two rapid assays of p53 function, namely the apoptotic assay and the FASAY as means of detecting germline p53 mutations in members of Li-Fraumeni and Li-Fraumeni-like families. Results of the functional assays have been compared with direct sequencing of all 11 exons of the p53 gene. The results show good agreement between the two functional assays and between them and sequencing. No false-positives or negatives were seen with either functional assay although the apoptotic assay gave one borderline result for an individual without a mutation. As an initial screen the apoptotic assay is not only rapid but inexpensive and very simple to perform. It would be expected to detect any germline defect that leads to loss of p53 function. The apoptotic assay could be ideal as a means of prescreening large numbers of samples and identifying those that require further investigation. The FASAY detects mutations in exons 4-10, is rapid and distinguishes between functionally important and silent mutations.

Apoptosis↗
PubMed2000

Reliability of immunohistochemical demonstration of oestrogen receptors in routine practice: interlaboratory variance in the sensitivity of detection and evaluation of scoring systems.

AIMS: To investigate interlaboratory variance in the immunohistochemical (IHC) detection of oestrogen receptors so as to determine the rate of false negatives, which could adversely influence the decision to give adjuvant tamoxifen treatment. METHODS: To ensure that similar results are obtained by different institutions, 200 laboratories from 26 countries have joined the UK national external quality assessment scheme for immunocytochemistry (NEQAS-ICC). Histological sections from breast cancers having low, medium, and high levels of oestrogen receptor expression were sent to each of the laboratories for immunohistochemical staining. The results obtained were evaluated for the sensitivity of detection, first by estimating threshold values of 1% and 10% of stained tumour cells, and second by the Quick score method, by a panel of four assessors judging individual sections independently on a single blind basis. The results were also evaluated using participants' own threshold values. RESULTS: Over 80% of laboratories were able to demonstrate oestrogen receptor positivity on the medium and high expressing tumours, but only 37% of laboratories scored adequately on the low expressing tumour. Approximately one third of laboratories failed to register any positive staining in this tumour, while one third showed only minimal positivity. CONCLUSIONS: There is considerable interlaboratory variability, especially in relation to the detection of breast cancers with low oestrogen receptor positivity, with a false negative rate of between 30% and 60%. This variability appears to be caused by minor differences in methodology that may be rectified by fine adjustment of overall technique.

Biomarkers, Tumor↗
PubMed2000

Frequency of oestrogen and progesterone receptor positivity by immunohistochemical analysis in 7016 breast carcinomas: correlation with patient age, assay sensitivity, threshold value, and mammographic screening.

AIMS: A routine immunohistochemical (IHC) assay is now commonly used for determining the oestrogen receptor (ER) and progesterone receptor (PR) status of women with breast cancer. To date, no large studies have been conducted that report the expected frequency of receptor positivity in relation to patient age and sensitivity of the IHC assay. Data on 7016 breast carcinomas from 71 laboratories were analysed to determine the frequency of receptor positivity and investigate possible causes of the observed variation in detection rates. METHODS: Members of UK NEQAS-ICC (UK National External Quality Assessment Scheme for Immunocytochemistry) provided data on the receptor status of cases routinely assayed in their departments over a period of two to 26 months between June 1996 and September 1998. Data on 7016 breast carcinomas were stratified according to patient age and receptor status. Frequency of receptor positivity was correlated with IHC assay sensitivity, the threshold value used to determine receptor positivity, and the presence or absence of mammographic screening in the hospitals or clinics served by the laboratories. RESULTS: The highest proportion of receptor positive cases occurred in patients in the age ranges > 65 years for ER and 41-50 years for PR. There was a significant positive correlation between frequency of receptor positivity and the sensitivity of the IHC assay, for both ER (rs = 0.346; p = 0.019; two tailed) and PR (rs = 0.561; p = 0.003; two tailed). The mean frequency of receptor positivity for laboratories using the same 10% threshold value was 77% for ER (95% confidence interval (CI), 74% to 80%) in laboratories with high sensitivity and 72% (95% CI, 68% to 76%) for those with low assay sensitivity (p = 0.025). For PR, the mean frequency of receptor positivity for laboratories using the same 10% threshold value and having high assay sensitivity was 63% (95% CI, 57% to 69%), and 51% (95% CI, 38% to 65%) for laboratories with assays of low sensitivity (p = 0.022). The mean frequency of ER positivity for laboratories serving hospitals and clinics where mammographic screening does and does not take place was 73.4% and 75.7%, respectively (p = 0.302; two tailed). CONCLUSIONS: Of the parameters investigated, patient age and IHC assay sensitivity were found to be the main variables influencing the frequency of receptor positivity. We recommend the range of receptor values obtained by laboratories achieving high assay sensitivity as a useful guide against which all laboratories can gauge their own results.

Adult↗
PubMed2000

Ocular pursuit responses to repeated, single-cycle sinusoids reveal behavior compatible with predictive pursuit.

The link between anticipatory smooth eye movements and prediction in sinusoidal pursuit was investigated by presentation of series of identical, single-cycle, sinusoidal target motion stimuli. Stimuli occurred at randomized intervals (1.2-2.8 s) but were preceded by an audio warning cue 480 ms before each presentation. Cycle period (T) varied from 0.64 to 2.56 s and target displacement from 4 to 20 degrees in separate series. For T </= 1.28 s, responses to the first stimulus of each series exhibited a time delay across the whole cycle (mean = 121 ms for T = 0.8 s). But, in the second and subsequent (steady-state) presentations, anticipatory movements, proportional to target velocity, were made and time delay was significantly reduced (mean = 43 ms for T = 0.8 s). Steady-state time delays were comparable to those evoked during continuous sinusoidal pursuit and less than pursuit reaction time. Even when subjects did not follow the target in the first presentation, they responded to the second presentation with reduced time delay. Throughout the experiments, three types of catch trial (A-C) were introduced. In A, the target failed to appear as expected after the warning cue. Anticipatory smooth movements were initiated, reaching a peak velocity proportional to prior target velocity around 200 ms after expected target onset. In B, the target stopped midway through the cycle. Even if the target remained on and was stationary, the eye movement continued to be driven away from the stationary target with a velocity similar to that of prior responses, reaching a peak velocity that was again proportional to expected target velocity after >/=205 ms. In C, the amplitude of the single sinusoid was unexpectedly increased or decreased. When it decreased, eye velocity throughout the first half-cycle of the response was close to that executed in response to prior stimuli of higher velocity and did not return to an appropriate level for 382-549 ms. Conversely, when amplitude increased, eye velocity remained inappropriately low for the first half-cycle. Results of A and C indicate that subjects are able to use velocity information stored from prior presentations to initiate an oculomotor drive that predominates over visual feedback for the first half-cycle. Results of B indicate that the second part of the cycle is also preprogrammed because it continued despite efforts to suppress it by fixation. The results suggest that initial retinal velocity error information can be sampled, stored, and subsequently replayed as a bi-directional anticipatory pattern of movement that reduces temporal delay and could account for predictive control during sinusoidal pursuit.

Adaptation, Physiological↗
PubMed2000

A review of the concept of culture in holistic nursing literature.

Core Value IV of the American Holistic Nurses' Association includes valuing the client's cultural background. The authors reviewed all article abstracts from two major holistic nursing journals for a 3-year period (N = 198). References to concepts of culture or ethnicity were found in only 9.6% of abstracts. Many theorists and researchers did not discuss how the theory or research findings varied between culturally or ethnically diverse samples. When culture is a core value, practitioners and researchers cannot assume that culture has been considered without stating what was the interaction of culture with the phenomenon of concern. The authors recommend that nurses develop cultural competence in caring for clients from differing cultural orientations by (a) committing to improve their knowledge of multiple cultures; (b) exploring their own cultural background; (c) seeking exposure to cultures other than their own; and (d) regularly discussing culture and ethnicity in nursing theory, research, and practice.

Clinical Competence↗
PubMed2000

A clinical evaluation of 10 percent vs. 15 percent carbamide peroxide tooth-whitening agents.

BACKGROUND: Agents with carbamide peroxide, or CP, in various concentrations are widely prescribed for at-home tooth whitening. It is not clear, however, if the more concentrated gels will whitening teeth to a greater extent, as no controlled clinical trials have been reported. The authors conducted a double-blind study of human subjects to evaluate whether a 15 percent CP tooth-whitening system was more effective than a 10 percent CP system, and to determine if tooth sensitivity increased with use of the higher concentration. METHODS: The authors recruited 57 subjects with maxillary anterior teeth of shade A3 or darker (as gauged against a value-oriented shade guide). The subjects were 18 to 65 years of age and in good general and dental health. After matching the subjects by sex and age, the authors randomly assigned them to either a control group, which used a 10 percent CP whitening agent, or an experimental group, which used a 15 percent CP agent. RESULTS: The results indicated that there was no significant difference in shade change between the groups after one week of treatment (t = 1.455, P = .05), but there was a significant difference at the end of the treatment period (t = 2.303, P < .05), as well as two weeks after treatment concluded (t = 2.248, P < .05). There was no significant difference in sensitivity (t = 1.399, P > .05). CONCLUSIONS: There was a significant difference in color change between the 10 percent CP and 15 percent CP groups at the end of the study period. There was no significant difference in level of tooth sensitivity between the two groups, and the incidence was equal; there was, however, a significant difference in variability of tooth sensitivity between the two groups. CLINICAL IMPLICATIONS: If performed under the careful guidance of a dentist, at-home whitening is an effective treatment, regardless of whether 10 percent CP or 15 percent CP is used. There may be added color change and varying sensitivity with the use of 15 percent CP.

Adolescent↗
PubMed2000

Patient and dentist satisfaction with a computerized local anesthetic injection system.

The fear of dental injections is common among dental patients. Many approaches to reducing this fear of injections and improving local dental anesthesia delivery have been tried in the last few decades. One approach is the use of a computerized or electronic local anesthetic system. This study surveyed dentist and patient satisfaction when local dental anesthesia was delivered with a computerized delivery system. The patients and dentists were both satisfied with the effectiveness of the anesthesia. The patients were satisfied with the level of comfort with the injections. This was particularly true when compared to their previous anesthetic injections. Although the dentists were very satisfied with the performance of the anesthetic delivery system and the anesthesia itself, they did not, in general, choose to use the system in everyday practice. Possible reasons for this within the context of this study are discussed.

Anesthesia, Dental↗
PubMed1999

Survival of premenopausal breast carcinoma patients in relation to menstrual cycle timing of surgery and estrogen receptor/progesterone receptor status of the primary tumor.

BACKGROUND: Premenopausal breast carcinoma patients who undergo tumor excision during the follicular phase of their menstrual cycle may have a significantly worse prognosis than those whose tumors are excised in other phases of the menstrual cycle. METHODS: Outcome was determined in a series of 112 premenopausal women with operable breast carcinoma in relation to the timing of surgery within the menstrual cycle and the estrogen receptor (ER) and progesterone receptor (PR) status of their primary tumors as determined by immunohistochemistry. RESULTS: Those patients with ER positive tumors who underwent surgery in the early and luteal phase of the cycle had a significantly better survival than women with ER negative tumors (chi-square test = 15.56; P < 0.001). This also was true for PR status (chi-square test = 18.21; P < 0.001). After follicular phase surgery, tumor receptor status had no effect on overall survival. Patients with the best prognosis had ER/PR positive tumors excised on Days 0-2 and 13-32 but even those women with ER or PR negative tumors removed during the luteal phase of their menstrual cycle fared better than patients whose tumors were removed during the follicular phase. CONCLUSIONS: There was a better survival rate for patients with both ER/PR positive and negative tumors treated during the luteal phase of the menstrual cycle. This could be the result of progesterone acting on the surrounding peritumoral normal tissue, thereby exerting a straitjacket effect and improving cohesion of the primary carcinoma. Unopposed estrogen in the follicular phase of the cycle may enable more tumor emboli to escape and successfully establish micrometastases.

Breast Neoplasms↗
PubMed1999

Effect of c-erbB(2) and estrogen receptor status on survival of women with primary breast cancer treated with adjuvant cyclophosphamide/methotrexate/fluorouracil.

We have investigated the relationship between c-erbB(2) status, estrogen receptor (ER) status and outcome in 274 women with node-positive breast cancer who, following excision and axillary clearance, were randomized to receive either 6 cycles of cyclophosphamide/methotrexate/fluorouracil (CMF) (n = 129) or no such treatment (n = 145). Follow-up data (median 13.3 years) were available on all patients. CMF improved relapse-free and overall survival of all women. The greatest benefit was seen in women with ER-negative tumors; the median overall survival of those given CMF was 11.6 years compared with only 2 years for the control group. For the women with ER-positive tumors the median overall survival of the CMF-treated women was 11.3 years compared with 7.7 years in the control group. When benefit from CMF was examined in relation to c-erbB(2) status, the women with c-erbB(2)-negative tumors who received CMF had a median overall survival of 12.7 years compared with only 7.3 years for the c-erbB(2)-negative women in the control group. The improvement in survival was less marked in the women with c-erbB(2)-positive tumors; median overall survival was 6.1 years for those who received CMF compared with 4.4 years for women in the control group. All women benefited from adjuvant CMF chemotherapy, those with ER-negative tumors benefiting the most. Int. J. Cancer (Pred. Oncol.) 84:354-359, 1999.

Adult↗
PubMed1999

Multiple effects of mercuric chloride on hexose transport in Xenopus oocytes.

HgCl(2) had both stimulatory and inhibitory effects on [(3)H]2-deoxyglucose (DG) uptake in Xenopus laevis oocytes. The Hg dose response was complex, with 0.1-10 microM Hg increasing total DG uptake, 30-50 microM Hg inhibiting, and concentrations >100 microM increasing uptake. Analyses of the effects of Hg on DG transport kinetics and cell membrane permeability indicated that low concentrations of Hg stimulated mediated uptake, intermediate concentrations inhibited mediated uptake, but high Hg concentrations increased non-mediated uptake. 10 microM Hg increased the apparent V(max) for DG uptake, but caused little or no change in apparent K(m). Phenylarsine oxide prevented the increase in DG uptake by 10 microM Hg, suggesting that the increase was due to transporter recruitment. Microinjecting low doses of HgCl(2) into the cell increased mediated DG uptake. Higher intracellular doses of Hg increased both mediated and non-mediated DG uptake. Both insulin and Hg cause cell swelling in isotonic media and, for insulin, this swelling has been linked to the mechanism of hormone action. Osmotically swelling Xenopus oocytes stimulated DG transport 2-5-fold and this increase was due to an increased apparent V(max). Exposing cells to 10 microM Hg or 140 nM insulin both increased cellular water content by 18% and increased hexose transport 2-4-fold. These data indicate that low concentrations of Hg and insulin affect hexose transport in a similar manner and that for both an increase cellular water content could be an early event in signaling the increase in hexose transport.

Animals↗
PubMed1999

Expression of c-erbB2 and p53 protein is similar in breast cancer from British and Japanese women.

In an attempt to explain the difference in outcome between British and Japanese women with breast cancer we have compared histopathological features, expression of c-erbB2 and p53 proteins and clinical outcome of 191 British (Anglo) women with 171 Japanese women treated between 1979 and 1980. The Japanese patients were significantly younger than the Anglo patients, while in premenopausal women the latter had significantly smaller tumors. The proportion of tumors expressing c-erbB2 and p53 proteins was similar in both populations. c-erbB2 positivity was significantly associated with positive lymph node status and with poorly differentiated carcinomas. Duration of relapse-free and overall survival was significantly longer in the Japanese women than in the Anglo women. Women with c-erbB2-negative tumors had a longer overall survival than women with c-erbB2-positive tumors and this difference was accentuated when patients were stratified according to country of origin. Japanese women with c-erbB2-negative tumors had the best outcome, whereas the Anglo women with c-erbB2-positive tumors had the worst. There was no relationship between p53 status and any histopathological features or clinical outcome. Differences in the expression of c-erbB2 and p53 do not explain the better outcome experienced by Japanese breast cancer patients.

Adult↗
PubMed1999

Time-related effects of estrogen withdrawal on proliferation- and cell death-related events in MCF-7 xenografts.

Endocrine treatments for human breast cancer have been based largely upon the removal of estrogenic stimuli. The regression of tumors after estrogen deprivation has generally been characterized as being due to reduced proliferation but more recently has been recognized to also involve increased apoptosis. The aim of our experiments was to define the associated changes in certain proliferation- and cell death-related biological parameters after hormone withdrawal from estrogen-dependent MCF-7 xenografts in athymic nude mice using immunohistochemical techniques. The baseline estrogen receptor (ER) level of this MCF-7 xenograft was relatively low (average H score 23) but it was strongly Bcl-2-, PgR- and pS2-positive, indicating the functional integrity of estrogen signaling. Changes in proliferation (Ki-67), apoptosis, ER, progesterone receptor (PgR), cyclin D1, p27kip1, Bcl-2 and Bax expression were assessed during the 2 weeks after estrogen deprivation. ER levels rose markedly after estrogen ablation, whereas PgR levels fell to about 10% of baseline and pS2 levels halved. The proportion of Ki-67-positive cells was unchanged after 24 hr but by day 14 had reduced by about 80%. The normal levels of cyclin D1 also reduced after estrogen withdrawal in contrast to the rapid increase in levels of cyclin-dependent kinase inhibitor p27kip1. This latter increase appeared to occur in advance of the changes in Ki-67. The proportion of apoptotic cells increased from a mean 1.5% at baseline to 2.9% after 3 days and 4.7% after 14 days. There were reductions in both Bcl-2 and Bax staining but these appeared to be greater for Bcl-2, effectively decreasing the Bcl-2/Bax ratio. Our results provide a framework for the use of these parameters as intermediate markers in comparisons of hormonal agents for human breast cancer treatment.

Animals↗
PubMed1999

Cyclin-dependent kinase inhibitor p27Kip1 expression and interaction with other cell cycle-associated proteins in mammary carcinoma.

p27, cyclin D1, and retinoblastoma (Rb) protein have been demonstrated using immunohistochemistry in 189 cases of primary breast carcinoma with long-term follow-up. There was a statistically significant association between the expression of p27 and both cyclin D1 and the retinoblastoma gene product (pRb), corresponding to their close interactions in regulating the G1/S transition in the cell cycle. Low levels of p27 were seen in high-grade, rapidly proliferating, oestrogen receptor-negative tumours. In univariate analysis, low p27 expression was associated with a reduced relapse-free and overall survival. In multivariate analysis, p27 was not an independent predictor of survival when either histological grade or proliferative activity (S-phase fraction) was included in the model. When the combined expression of p27 and cyclin D1 was related to survival, patients with high levels of p27, regardless of their cyclin D1 status, did well, whilst those with low p27 had a poor outcome. The only exception, in the latter group, was patients with tumours expressing high levels of cyclin D1, who did as well as the high p27 group. We have shown that in clinical material p27 expression is associated with proliferative activity and while univariate analysis shows it to be a significant indicator of prognosis, this significance is lost in multivariate analysis when traditional prognostic factors are included in the model. The interest in p27 expression in mammary carcinoma lies in its behaviour when examined in combination with other G1 cell cycle regulators.

Biomarkers, Tumor↗
PubMed1999

p21(WAF1) expression and endocrine response in breast cancer.

An immunocytochemical assay for the p53-regulated protein product of the WAF1/Cip1 gene, p21(WAF1) (p21), was developed and applied to archival primary breast tumour material from 91 patients whose subsequent recurrent disease was treated with assessable courses of endocrine therapy. Nuclear localization of p21 protein was observed in 76 (82.4 per cent) cases. Status cut-offs were established and 29 (31.9 per cent) were deemed negative, 39 (42.9 per cent) weakly positive, and 23 (25.3 per cent) strongly positive. p21 status was inversely correlated with p53 protein (p=0.047) but did not relate to oestrogen receptor (ER) status, response to endocrine therapy, or time to further disease progression (TTP). Highly p21-positive patients had a significantly improved overall survival time (p=0. 020). Co-assessment of p21 and p53 subgroups revealed p21+/p53- patients to have good survival characteristics, whilst p21-/p53+ patients did poorly (p=0.008). The p21-/p53- patients overall did intermediately well, but Ki67-defined cellular proliferation analysis of these revealed two subclasses: those with high proliferation and poor survival times resembling the p21-/p53+ phenotype, and those with less proliferative tumours with good survival, similar to the p21+/p53- group. The significance of these results is discussed in the light of recent research concerning the role of p21 and p53 in breast cancer aetiology.

Adult↗