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Biomedical subjects

C Jarvis

Publications and source records attributed to C Jarvis.

At least 19 recordsLinked to original sources
PubMed2004

Increased risk of malignant progression in benign proliferating breast lesions defined by expression of heat shock protein 27.

Heat shock protein 27 (hsp-27) is a regulator of oestrogen receptor (ER) expression and a modulator of intracellular homeostasis. In this laboratory, Shaaban et al demonstrated the importance of ER-alpha, together with Ki67, in enhancing the progression of benign breast lesions of defined morphological types. To better understand the mechanisms by which ER-alpha promotes breast neoplasia, this study was performed to test the hypothesis that the roles of ER-alpha and hsp-27 may be defined by their quantitative expression in proliferative breast lesions of varying histological risk. The expression of hsp-27 was identified using a specific monoclonal antibody and analysed to assess the proportion of positive epithelial cells using digitised morphometric image analysis. The expression of ER-alpha was analysed by immunohistochemistry and Western blotting in a variety of benign (HUMA121) and malignant mammary cell lines, including ER-alpha(+) (MCF7, ZR-75, T47D) and ER-alpha(-) (MDA-MB 231) breast cancer cell lines. The data confirm that, during progression from normal through proliferative breast lesions to in situ cancer, there was a significant increase in both the proportion and the optical density of the epithelial cells expressing hsp-27. The mean levels of expression ranged from 7.4% of the total number of epithelial cells in normal lobules to 25.17% of epithelial cells in hyperplasias of usual type (HUT) to 61.1% of epithelial cells in ductal carcinoma in situ (P<0.001). The study has confirmed the expression of hsp-27 to be closely associated with ER-alpha(+) expression, and that its regulated expression occurs early along the mammary oncogenic pathway, supporting the initial hypothesis. It is our proposal that the differential expression of hsp-27 modulates the phenotypic behaviour of morphologically benign epithelial cells and hence may be an important determinant in initiating, or promoting, a population of human mammary cancers.

Biomarkers, Tumor↗
PubMed2003

Angiogenesis and invasive recurrence in ductal carcinoma in situ of the breast.

The development of an invasive recurrence following treatment for ductal carcinoma in situ (DCIS) converts a non-fatal disease to one associated with mortality. To date, no pathological or molecular features have been found to predict for the type of recurrence. Previous studies have suggested that in DCIS angiogenesis may be an important factor in determining the transformation from in situ to invasive carcinoma. We looked at 355 cases of DCIS and found that 32 had subsequently developed recurrent disease. In these 32 cases and in matched controls, periductal vascular density was determined using morphometry and anti-endothelial antibodies, von Willebrand factor (vWF) and CD34. Vascular density was related to the risk of both invasive and in situ recurrence. Normal lobules at least 2 mm away were used as controls. Differences in the phenotype of individual blood vessels was detected by performing dual staining immunofluorescence on selected cases. The microvessel density (MVD), as detected with the CD34 antibody, was higher around foci of DCIS than around normal breast lobules (P=0.001). Furthermore, it was significantly higher in cases of DCIS that recurred (P<0.0001). The findings with the vWF antibody were less clear cut and suggested a trend in decreasing MVD with increasingly aggressive disease. Dual immunofluorescence staining shows that the increase in MVD seen around DCIS is due to an increase in CD34+/vWF-blood vessels. An increase in CD34+/vWF-of blood vessels may be able to predict cases of DCIS that are at a high risk of developing a recurrence.

Aged↗
PubMed2003

Thymidine phosphorylase expression and stromal vascularity in ductal carcinoma in situ of the breast.

AIMS: Periductal angiogenesis in ductal carcinoma in situ is associated with an increased risk of subsequently developing a recurrence. This study aimed to (1) identify the relation between periductal and stromal vascularity and recurrence and (2) determine whether thymidine phosphorylase (TP) is associated with angiogenesis or recurrence in ductal carcinoma in situ (DCIS). METHODS: Twenty cases of DCIS that did not subsequently recur, 20 that developed a subsequent in situ recurrence, and 12 that developed a subsequent invasive recurrence were investigated. Periductal and stromal (hotspot) microvessel density were determined quantitatively using antibodies to CD34 and von Willebrandt factor (vWF). TP expression by DCIS was assessed semiquantitatively using the H score method. RESULTS: Stromal and periductal microvessel density assessed by anti-vWF gave similar mean values, and showed a strong positive correlation. When angiogenesis was assessed with anti-CD34 this association was lost. Not only were the mean values for both types of microvessel density higher than those obtained with anti-vWF, but the periductal microvessel density was significantly greater than the stromal microvessel density. TP expression was associated with stromal microvessel density assessed with anti-vWF, but not with anti-CD34. TP expression was not related to recurrence. No significant difference was identified in TP expression or stromal vascularity in DCIS between cases that recurred as DCIS and those that recurred as invasive carcinoma. CONCLUSIONS: Recurrent in situ or invasive disease after excision of DCIS does not appear to be related to stromal microvessel density or to TP expression by DCIS cells.

Adult↗
PubMed2002

Vascular density and phenotype around ductal carcinoma in situ (DCIS) of the breast.

Up to 50% of recurrences of ductal carcinoma in situ of the breast are associated with invasive carcinoma but no pathological or molecular features have yet been found to predict for the development of invasive disease. For a tumour to invade, it requires the formation of new blood vessels. Previous studies have described a vascular rim around ducts involved by ductal carcinoma in situ, raising the possibility that the characteristics of periductal vascularisation may be important in determining transformation from in situ to invasive disease. Periductal vascular density and phenotype were determined using morphometry and a panel of anti-endothelial antibodies (von Willebrand factor, CD31, CD141 and CD34) and related to the presence of invasive carcinoma and other histological features. Compared to normal lobules, pure ductal carcinoma in situ exhibited a greater density of CD34+ and CD31+ vessels but a decrease in those that were immunopositive for vWF, indicating a difference in phenotype and in density. Ductal carcinoma in situ associated with invasive carcinoma showed a profile of vascular immunostaining similar to that of pure ductal carcinoma in situ but there were significantly greater numbers of CD34+ and CD141+ vessels and fewer staining for vWF. There was a significant negative correlation between vascular density and both the cross-sectional areas of the ducts involved and the extent of the necrosis of the tumour they contained. A correlation between vascular density and nuclear grade was also noted, being highest in the intermediate grade. The greater density of CD34+ and CD141+ vessels around ductal carcinoma in situ associated with invasive carcinoma could reflect a greater predisposition to invade but a direct effect of co-existent invasive carcinoma cannot entirely be ruled out in the present study. The relationship between vascular density, grade, duct size and nuclear grade suggests that periductal angiogenesis increases with tumour growth rate but is unable to keep pace with the most rapidly growing lesions.

Antigens, CD34↗
PubMed2002

Histopathologic types of benign breast lesions and the risk of breast cancer: case-control study.

The hypothetical multistep model of carcinogenesis indicates that breast cancer develops via a series of intermediate hyperplastic lesions through in situ to invasive carcinoma. To identify the risk inherent within the different morphologic lesions, we have analyzed the data from 674 benign biopsy specimens comprising 120 cases who subsequently developed breast cancer and 382 controls (matched for age and date of biopsy) spanning a period up to 20 years of follow-up (mean 66.95 months). In this series we have confirmed an increased risk associated with certain types of benign breast lesions. Atypical lobular hyperplasia was the most significant risk factor for breast cancer with more unfavorable outcome in patients <50 years of age (p = 0.003) and a relative risk (RR) of 4.55 (confidence interval [CI] 1.77-11.69). Hyperplasia of usual type showed an RR of 1.53 (CL 1.10-2.13) with a statistically worse probability of survival (cancer-free time) for patients >50 years. For atypical ductal hyperplasia the RR was 2.03 (CI 0.80-1.39). Blunt duct adenosis was significantly more common in cases progressing to breast cancer compared with controls, showing an RR of 2.08 (CI 1.12-2.85). We describe in detail the criteria of morphologic changes observed in blunt duct adenosis and define, for the first time, the level of risk associated with each of its six subtypes. Improved knowledge of breast carcinogenesis will provide insight for defining high-risk groups thus resulting in improved screening and management regimens.

Age Factors↗
PubMed2001

Modulation of the binding affinity of myelopoietins for the interleukin-3 receptor by the granulocyte colony-stimulating factor receptor agonist.

Myelopoietins (MPOs) are a family of recombinant chimeric proteins that are both interleukin-3 (IL-3) receptor and granulocyte colony-stimulating factor (G-CSF) receptor agonists. In this study, MPO molecules containing one of three different IL-3 receptor agonists linked with a common G-CSF receptor agonist have been examined for their IL-3 receptor binding characteristics. Binding to the alpha-subunit of the IL-3 receptor revealed that the affinity of the MPO molecules was 1.7-3.4-fold less potent than those of their individual cognate IL-3 receptor agonists. The affinity decrease was reflected in the MPO chimeras having approximately 2-fold slower dissociation rates and 2.7-5.5-fold slower association rates than the corresponding specific IL-3 receptor agonists alone. The affinity of binding of the MPO molecules to the heteromultimeric alphabeta IL-3 receptor expressed on TF-1 cells was either 3-, 10-, or 42-fold less potent than that of the individual cognate IL-3 receptor agonist. Biophysical data from nuclear magnetic resonance, near-UV circular dichroism, dynamic light scattering, analytical ultracentrifugation, and size exclusion chromatography experiments determined that there were significant tertiary structural differences between the MPO molecules. These structural differences suggested that the IL-3 and G-CSF receptor agonist domains within the MPO chimera may perturb one another to varying degrees. Thus, the differential modulation of affinity observed in IL-3 receptor binding may be a direct result of the magnitude of these interdomain interactions.

Binding, Competitive↗
PubMed2001

Immunodetectable cyclin D(1)is associated with oestrogen receptor but not Ki67 in normal, cancerous and precancerous breast lesions.

Cyclin D1 is associated with cell cycle regulation and has more recently been shown to stimulate the transcriptional functions of the oestrogen receptor (ER). Furthermore, in normal breast there is a negative association between expression of ER and the proliferation marker Ki67 indicating that either ER positive cells are non-dividing or that the receptor is down-regulated as cells enter cycle. This important relationship breaks down in many ER-positive cancers and precancerous breast lesions where the receptor is often detected on proliferating cells. The aims of the present study were to determine the interplay between ER, Ki67 and cyclin D(1)in individual cells within the spectrum of human breast lesions ranging from normal to invasive carcinoma by using dual staining immunofluorescence. We found that in normal breast there was a strong positive association between ER and cyclin D(1)expression. In contrast there was a strong negative association between cyclin D(1)and Ki67 expression. Similar findings were seen for the other precancerous and cancerous breast lesions. Thus immunodetectable cyclin D(1)within individual cells does not appear to be associated with cell cycle progression in the benign or malignant breast but instead may have important interactions with ER.

Antibodies, Monoclonal↗
PubMed2001

Subgroups of non-atypical hyperplasia of breast defined by proliferation of oestrogen receptor-positive cells.

In normal breast, there is a negative association between expression of oestrogen receptor (ER) and the proliferation marker Ki67, indicating that ER-positive (ER+) cells do not divide, or that the receptor is down-regulated when they do so. However, dual staining has been found in carcinomas and precancerous lesions, indicating that abnormal regulation of ER could be important in breast tumourigenesis. ER expression in relationship to cell proliferation was studied in 241 foci of hyperplasia of usual type (HUT), a lesion associated with a 1.5 to 2-fold increase in risk of developing breast cancer. Dual label immunofluorescence was employed, using the antibodies 1D5 and Ki67. Two hundred and thirteen foci of HUT contained ER+ cells, which were distributed singly or contiguously and increased with age. Most foci resembled normal breast, but 51 contained dual labelled cells, which did not increase with age. Some of these foci exhibited few, scattered ER+ cells with greater proliferation rates than the ER-negative (ER-) cells, whereas others contained many, contiguous ER+ cells, whose rate of proliferation was less than that of the ER- cells. The latter picture is similar to that which has previously been reported in atypical ductal hyperplasia and ductal carcinoma in situ. The first type of HUT may evolve into the second. The proportion of Ki67+ cells that was ER+ was similar in both types, suggesting a homeostatic mechanism that slows the proliferation of ER+ cells as they become confluent. Overriding this inhibition may be crucial in further progression. Non-atypical hyperplasia is thus heterogeneous in ER expression and proliferation and a significant proportion exhibit abnormal regulation of ER. These findings could have implications for pathological diagnosis, risk assessment, and prophylactic hormonal therapy.

Adult↗
PubMed2001

Furano pyrimidines as novel potent and selective anti-VZV agents.

Bicyclic furano pyrimidine nucleosides have been found to be highly potent and selective inhibitors of varicella zoster virus (VZV). They are inactive against herpes simplex virus and have been known for several decades as (unwanted) synthetic by-products in the Pd-catalysed coupling of acetylenes to 5-iodo nucleosides. These fluorescent bicyclic nucleosides are now established as a new family of potent antivirals. They are unusual in that they exhibit complete specificity for VZV and require an alkyl (or alkylaryl) side-chain for biological activity. The latter requirement confers extremely high lipophilicities on these compounds, unknown amongst chemotherapeutic nucleosides, which may be of considerable importance in formulation, dosing and tissue distribution. The most potent compounds reported are p-alkylaryl compounds, with EC50 values below 1 nM versus VZV and selectivity index values of around 1,000,000. Here, we review the discovery, synthesis, characterization, antiviral profile, SAR, mechanism of action and development prospects for this new family of antivirals.

Antiviral Agents↗
PubMed2000

Cellular events linked to cardiac remodeling in heart failure: targets for pharmacologic intervention.

Over the past decade, there has been a paradigm shift in the understanding of heart failure pathophysiology. Heart failure is no longer conceptualized as a hemodynamic disorder resulting from changes in renal and hormonal function. Rather, the syndrome of heart failure is more complex and is characterized by abnormal myocyte growth, proliferation of cells in the extracellular matrix, and myocyte cell loss (apoptosis)--all of which culminate in significant structural remodeling of the heart and loss of ventricular function. The loss of ventricle function is preceded by an initiating event such as myocardial infarction, which leads to changes in cell function, activation of specific neurohormones and peptides, which in turn are linked to the remodeling of the ventricle, and progression of heart failure. This article discusses how changes in myocyte and nonmyocyte structure may contribute to the progression of heart failure. Insight into these mechanisms will provide a better understanding of newer pharmacologic approaches in the treatment of heart failure.

Apoptosis↗
PubMed2000

Abnormal regulation of the oestrogen receptor in benign breast lesions.

BACKGROUND: In normal breast tissue the oestrogen receptor (ER) and the proliferation associated antigen Ki67 are negatively associated, indicating that ER+ cells are non-dividing, or that the receptor is downregulated as cells enter cycle. This relation is completely or partially lost in many ER+ breast cancers and in in situ proliferations associated with an increased cancer risk, where coexpression of the two markers is often found. AIMS: To determine whether similar changes can be identified in other risk associated breast lesions. PATIENTS/METHODS: Paraffin wax blocks from 12 cases of lactational change, 21 apocrine metaplasias, 22 duct ectasias, 20 sclerosing adenosis, 20 fibroadenomas, 19 phyllodes tumours, 20 radial scars, 21 papillomas (15 solitary and six multiple), 15 gynaecomastias, and nine postmortem male breast tissues were retrieved. Immunohistochemistry was used to determine the expression of ER and dual labelling immunofluorescence was used to detect cells expressing both ER and Ki67. RESULTS: Increased numbers of ER+ cells were seen in sclerosing adenosis, radial scars, papillomas, fibroadenomas, and phyllodes tumours but not in apocrine cysts (where no ER+ cells were detected) or duct ectasia (where normal numbers were found). As in the normal breast, the proportion of ER+ cells increased with age in all lesions with the exception of fibroadenomas. Coexpression of ER and Ki67 was found in an increased proportion of cells of all risk associated lesions studied. ER+ cells were less likely to be dividing than ER- cells in all cases, although this was significant only for sclerosing adenosis. The data on sclerosing adenosis, radial scars, papillomas, and fibroadenomas are comparable with those reported previously in hyperplasia of usual type, whereas those in duct ectasia are similar to those of the normal breast. The findings in all lesions, however, differed from those in ductal carcinoma in situ, where proportions of ER+ and ER+/Ki67+ cells are higher and the relation between ER+ cell numbers and age is lost. Thus, the nature and degree of dysregulation of ER in benign breast lesions is broadly in accordance with the degree of risk of developing breast cancer with which they are associated. In gynaecomastia, the proportions of ER+ and ER+/Ki67+ cells were comparable with those seen in benign female breast lesions, but changes with age were not observed. However, the changes in gynaecomastia were similar to those seen in normal male breast. CONCLUSION: These findings are in keeping with the contention that the dissociation of ER and Ki67 expression is a very early change in the pathway to many breast cancers. However, this change might only have preneoplastic importance in the hormonal milieu of the female breast.

Adult↗
PubMed1999

Oestrogen receptor expression in the normal and pre-cancerous breast.

As oestrogen is associated with most of the epidemiological risk factors for breast cancer, the number and distribution of oestrogen receptor positive (ER+) cells could have a bearing on the development of the disease. ER+ cells were thus studied in the normal breast and in the spectrum of in situ proliferations which range from non-atypical hyperplasia to in situ carcinoma and are associated with different levels of risk for developing breast cancer. In the normal pre-menopausal breast, ER+ cells comprised the minority and were distributed singly, being surrounded by oestrogen receptor negative (ER-) cells. ER+ cells showed a statistically significant increase with age, reaching a plateau after the menopause, and the increase was associated with a tendency for positive cells to become contiguous in patches of variable size. A small proportion of lobules showing involutional change comprised over 90 per cent ER+ cells. The significance of this feature is not clear but no evidence was found that it was pre-cancerous. The percentage of ER+ cells was slightly increased in hyperplasia of usual type (non-atypical hyperplasia, HUT) and the relationship to age was maintained. The staining pattern was variable; in some lesions ER+ cells were surrounded by ER- cells whereas in others there were contiguous groups of positive cells sometimes accounting for more than 90 per cent of cells in the lesion. In contrast, all cases of atypical ductal hyperplasia (ADH), lobular in situ neoplasia (LIN) and ductal carcinoma in situ (DCIS) exhibited positivity of contiguous cells accounting for the majority in the lesions. Furthermore, the relationship between ER+ cell numbers and age was lost in these lesions, indicating autonomy of ER expression or of proliferation of cells expressing the receptor. It is hypothesized that this dysregulation of receptor expression or of ER+ cell numbers at the ADH stage may be the precursor of abnormal expression of cyclins and other cell cycle control proteins which have been shown first to appear in DCIS.

Adult↗
PubMed1999

Estrogen receptor-positive proliferating cells in the normal and precancerous breast.

Recently it has been shown that epithelial cell expression of the estrogen receptor (ER) and that of the proliferation-associated marker Ki-67 are almost mutually exclusive in the normal premenopausal human breast but that coexpression frequently occurs in estrogen receptor-positive (ER+) breast cancers. This coexpression may indicate disordered expression of ER in the cell cycle or failure to suppress division of ER+ cells and could be important in neoplastic transformation. The purpose of this study was to determine whether in situ proliferations known to be associated with different levels of risk for developing breast cancer contain these coexpressing cells and, if so, the stage at which they occur. We found that ER+ proliferating cells were rare in premenopausal lobules but increased with age in the normal breast. There was no difference in nonlesional tissue between cancerous and noncancerous breasts. The percentage of dual-expressing cells was significantly increased, however, in all of the in situ proliferations and correlated positively with the level of risk of developing breast cancer. We suggest that development of at least some human breast cancers is associated with increasing failure to down-regulate ER as cells enter the cycle or to suppress division of ER+ cells. The mechanism may involve the loss of a tumor suppressor gene.

Breast↗
PubMed1999

Total parenteral nutrition and cholestasis.

Hepatobiliary dysfunction is recognized as a major adverse effect of total parenteral nutrition (TPN). It is unknown if this is caused by a deficiency or toxicity of the TPN solution or the underlying pathophysiology of disease processes that require TPN therapy. This article presents algorithms for evaluating abnormal liver tests in patients on TPN and discusses treatment options and the current status of intestinal transplantation.

Cholestasis↗
PubMed1996

Evaluation of elite British cyclists: the role of the squad medical.

OBJECTIVE: To describe and report results from the procedures and protocols used by the British Cycling Federation during the squad medicals of its elite cyclists. METHODS: Screening of over 500 elite riders has been done by doctors, dentists, physiotherapists, opticians, and dietitians since 1990. A questionnaire provided additional information on musculoskeletal problems. RESULTS: 523 riders have been examined and 92 (17.5%) have been referred for further assessment or treatment. Most of these riders were sent either to their own general practitioner or to the British Olympic Medical Centre. The questionnaire was completed by 81% of riders. Low back pain was the most common problem that riders encountered (60%), and knee pain the second most common (33%). Four riders failed the eye examination, and a further 11 were classed as borderline. Twenty one per cent of riders undergoing dental examination needed further dental treatment. CONCLUSIONS: The squad medical is an important and useful strategy for evaluating elite British cyclists. It shows that a structured system can help early diagnosis and treatment to provide injury-free cyclists at the start of a competitive season. The results from the questionnaire confirm previously unsubstantiated opinions about the incidence of musculoskeletal injuries in cyclists.

Athletic Injuries↗
PubMed1994

Ntk: a Csk-related protein-tyrosine kinase expressed in brain and T lymphocytes.

The activity of Src-related protein-tyrosine kinases is repressed by the phosphorylation of a conserved carboxyl-terminal tyrosine by another cytoplasmic protein-tyrosine kinase termed p50csk. In this study, we characterize Ntk, a protein-tyrosine kinase bearing striking similarities to p50csk. Like p50csk, Ntk possesses Src homology 3 and Src homology 2 domains and lacks the consensus tyrosine phosphorylation and myristoylation sites found in members of the Src family. Expression of ntk transcripts was maximal in brain, and was observed at significant levels in thymus and spleen. ntk RNA levels were dramatically reduced upon mitogenic stimulation of normal T lymphocytes and were minimal in transformed T-cell populations. Firm evidence that Ntk is a Csk-related enzyme was provided by the observation that it phosphorylated a Src-related polypeptide on the inhibitory carboxyl-terminal tyrosine. These findings indicate that Ntk is a Csk-related enzyme that may play an inhibitory role in the control of T-cell proliferation.

Amino Acid Sequence↗
PubMed1994

Differential susceptibilities of enterococcal species to elfamycin antibiotics.

The elfamycins are a class of naturally occurring antibiotics not currently used in the therapy of human disease. Enterococcus faecium and closely related species (Enterococcus durans and Enterococcus hirae) are susceptible to these antibiotics, while isolates of Enterococcus faecalis and other enterococcal species are highly resistant. Among enterococci, susceptibility or resistance to elfamycins appears to be determined by the bacterial protein synthesis elongation factor EF-Tu. Elfamycin susceptibility may be a useful adjunct for rapidly distinguishing E. faecalis and E. faecium in the clinical microbiology laboratory and/or as a supplementary test for use in determining the species of enterococci.

Anti-Bacterial Agents↗