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Biomedical subjects

C M Hughes

Publications and source records attributed to C M Hughes.

At least 73 records · Page 4Linked to original sources
PubMed1991

Abnormalities of the p53 tumour suppressor gene in human pancreatic cancer.

The tumour suppressor gene p53 has been found to be mutated or inactivated at high frequency in several common human tumours. We have examined a series of exocrine pancreatic carcinomas for over-expression of mutant forms of p53 by immunohistochemistry with a panel of specific antibodies. We found immunodetectable p53 in 13 of 22 (60%) frozen pancreatic cancers and seven of 13 pancreatic cell lines. One of the antibodies, CM1, recognises p53 in formalin-fixed, paraffin-embedded archival material and using this reagent we found immunodetectable p53 in 28 of 124 (23%) pancreatic cancers. We have successfully demonstrated the presence of point mutations by direct sequencing of genomic DNA extracted from archival tissue showing CM1 immunoreactivity. We conclude that p53 activation is an important event in human pancreatic tumorigenesis and that the CM1 antibody can detect a proportion of cases of overexpression of mutant p53 in archival pathological material.

Antibodies, Monoclonal↗
PubMed1990

The c-erb B-2 proto-oncogene in human pancreatic cancer.

The c-erb B-2 oncogene encodes a 190 kD transmembrane growth factor receptor which is closely related to the EGF receptor and has been found to be amplified and overexpressed in a number of human adenocarcinomas, particularly of the breast. We have analysed, by immunocytochemistry using the 21N antibody, expression of c-erb B-2 in a retrospective series of pancreatic adenocarcinoma, chronic pancreatitis, and examples of histologically normal pancreas. In three cases (21 per cent) of chronic pancreatitis, there were focal areas of cytoplasmic immunoreactivity in regenerating epithelium. In 15 cases (17 per cent) of pancreatic adenocarcinoma, cytoplasmic immunoreactivity was seen, while in two cases (2 per cent) strong membrane staining of tumour cells was seen which could be blocked by peptide controls. c-erb B-2 immunoreactivity was also demonstrated using a second antibody, 20N, which recognizes another peptide sequence of the c-erb B-2 protein. There was no relationship between immunoreactivity and histological subtype or grade, but there was absolute concordance between staining in primary and metastatic deposits. Since the rat homologue (neu) of the c-erb B-2 oncogene may be activated by a specific point mutation in its transmembrane region, we have analysed 23 cases from this series for mutations by polymerase chain reaction amplification and sequence-specific oligonucleotide hybridization. We were unable to identify activity mutations in this series. These data suggest that there is abnormal expression of c-erb B-2 oncogene in nearly 20 per cent of cases although mutational activation of this gene is not seen in human pancreatic adenocarcinoma.

Adenocarcinoma↗
PubMed1990

c-erbB-2 oncogene expression in ovarian cancer.

One hundred and four common epithelial malignancies of the ovary were stained for c-erbB-2 using an affinity-purified polyclonal antibody 21N. Twenty-three out of 104 (22.1 per cent) showed cytoplasmic staining alone. Nine out of 104 (8.7 per cent) showed both membrane and cytoplasmic staining. In a multivariate Cox analysis with other known risk factors the relative risk for cytoplasmic staining alone was 1.456 (chi 2 = 1.71, P greater than 0.1) and for membrane and cytoplasmic staining 0.316 (chi 2 = 7.95, P less than 0.005). These results do not support an adverse prognostic effect of c-erbB-2 in our patients.

Aged↗
PubMed1990

Morphological evidence for callosally projecting nonpyramidal neurons in rat visual cortex.

This investigation shows that some of the callosally projecting neurons in rat visual cortex are nonpyramidal cells. Callosally projecting neurons were labeled by injections of horseradish peroxidase (HRP) into the area 17/18a border zone of the contralateral hemisphere. The retrogradely transported HRP was visualized with diaminobenzidine or with tetramethylbenzidine. In some of the labeled neurons the reaction product was diffuse, so that the neurons had a Golgi-like appearance, but in others the reaction product was granular, or punctate. The majority of neurons with a Golgi-like appearance were pyramidal cells, but one callosally projecting neuron from layer V area 18a was confirmed by electron microscopy to be a nonpyramidal neuron. This dearth of well-filled nonpyramidal cells suggested that callosally projecting nonpyramidal neurons may not transport sufficient HRP to show Golgi-like filling, and so punctately labeled neurons from areas 17, 18a and 18b were examined. Reacted sections from areas 17, 18a and 18b of control animals, into which no tracer had been injected, were also examined, but in these control preparations no granules similar to the HRP granules within the neuronal profiles of the experimental animals were encountered. In methylene blue-stained 1-microns sections, neuronal profiles from the control animals possessed only blue staining lysosomes, while neuronal profiles from the experimental animals exhibited both lysosomes and HRP granules. It was determined, from the counts of HRP granules in neurons from the experimental animals, that in selected regions of areas 17, 18a, and 18b similar percentages of the pyramidal and nonpyramidal neuronal populations (ranging from 100% to 34%) contained HRP granules, and so had callosally projecting axons. However, most callosally projecting nonpyramidal neurons had far fewer HRP granules than the pyramidal neurons, again indicating that they transport less HRP. This could account for the fact that callosally projecting nonpyramidal neurons only rarely show a Golgi-like filling, and this could be one reason why such cells have been overlooked in most previous studies.

Animals↗
PubMed1990

Absence of abnormalities of the c-erbB-1 and c-erbB-2 proto-oncogenes in human thyroid neoplasia.

The c-erbB-1 and c-erbB-2 proto-oncogenes are frequently activated by gene amplification and overexpression in a variety of human cancers. In an analysis of a large series of benign and malignant thyroid tumours, no abnormalities of structure or expression of either of c-erbB-1 or c-erbB-2 were found. Activation of these oncogenes is not a necessary event in neoplasia of this epithelial system.

DNA, Neoplasm↗
PubMed1990

Immunocytochemical identification of myoepithelial cells in normal and neoplastic rat mammary glands with the lectins Griffonia simplicifolia-1 and pokeweed mitogen.

Peroxidase-conjugated Griffonia simplicifolia-1 (GS-1) and pokeweed mitogen (PWM) histochemically stain only the myoepithelial cells and not the epithelial or fibroblastic cells of rat mammary glands preserved in methacarn or glutaraldehyde and embedded in paraffin. This pattern of staining occurs in other rat exocrine glands except the pancreas, but is the reverse of that seen in most lining epithelium. The histochemical binding of GS-1 and PWM to myoepithelial cells is inhibited specifically by D-galactose and by polymers of N-acetylglucosamine, respectively. GS-1 and its subcomponent, GS-1-B4, also bind to extracellular structures similar to those stained by anti-laminin serum. At the ultrastructural level, both conjugated GS-1 and PWM bind to the plasma membrane of the myoepithelial cells, as well as to the adjacent basement membrane. Non-metastasizing rat mammary tumors produced by dimethylbenz[a]anthracene, by derivative epithelial stem-cell lines, and by a transplantable tumor all contain more elongated myoepithelium-like cells as well as cuboidal epithelium-like cells; both cell types are neoplastic. The more elongated myoepithelium-like cells are stained by GS-1 and PWM, whereas the cuboidal epithelium-like cells are unstained. Moderately and strongly metastatic rat mammary tumors produced by epithelial cell lines and by transplantable tumors, respectively, contain no such neoplastic cells that bind either lectin. We suggest that the carbohydrate receptors for GS-1 and PWM are consistent markers for the presence of the myoepithelial cell in normal and tumorous rat mammary glands.

Animals↗
PubMed1990

Appearance of myoepithelial cells in developing rat mammary glands identified with the lectins Griffonia simplicifolia-1 and pokeweed mitogen.

The histochemical binding of peroxidase-conjugated Griffonia simplicifolia-1 (GS-1) and pokeweed mitogen (PWM) to methacarn-preserved and paraffin-embedded female rat mammary glands at different developmental stages has been undertaken with a view to investigating the ontogeny of the myoepithelial cell. Conjugated GS-1 fails to stain the outer layer of ductal cells in neonatal rats up to 3 days old, but thereafter the staining increases so that all such cells are intensely stained in rats 5 days old and in mature, pregnant, and lactating rats. Conjugated GS-1 also stains most of the inner epithelial cells that line the ducts in neonatal rats up to about 5 days after birth; thereafter no such cells are stained in mature, pregnant, and lactating rats. Conjugated PWM stains both the inner and outer cell layers of ducts in neonatal rats up to 5 days old; thereafter the fraction of strongly stained cells declines rapidly in both cell layers so that in 6-day-old rats only weak staining is visible. Staining with PWM continues to decline for the inner epithelial cells of the ducts until it ceases when the rats mature; in contrast, that for the outer cell layer of the ducts increases so that all such cells are stained intensely when the rats mature. This pattern of ductal staining with PWM is maintained for pregnant and lactating rats. In terminal end buds of mammary ducts of prepubertal rats, GS-1 binds mainly to the peripheral or cap cells, the staining intensity increasing from cap cells at the distal tip to myoepithelial cells of the subtending duct. PWM binds to many more of the cortical epithelial cells and fewer of the cap cells. At the ultrastructural level, cap cells and adjacent immature myoepithelial cells both bind GS-1 and PWM to their surfaces, but basal clear cells do not. In alveolar buds and in alveoli, both conjugated lectins GS-1 and PWM bind to myoepithelial cells but not to epithelial cells of the rat mammary gland. We suggest that the appearance of carbohydrate receptors for GS-1 and PWM marks specific stages of myoepithelial cell differentiation in developing rat mammary glands.

Animals↗
PubMed1989

Localization of vimentin in myoepithelial cells of the rat mammary gland.

Myoepithelial cells in the virgin rat mammary gland have been shown to contain vimentin, using a polyclonal antiserum to vimentin purified from hamster fibroblasts. This antiserum has been shown to be specific for vimentin by immunoblotting and ELISA techniques. Similar results were obtained with a monoclonal antibody to vimentin. In the mammary glands of pregnant rats, the staining with vimentin antibodies is much weaker in the myoepithelial cells of the developing alveolar buds than in the main ducts. Similarly, in lactating glands, the staining of myoepithelial cells is much weaker in the secretory alveoli than in lactiferous sinuses. In each case, staining with antivimentin co-localizes with staining with polyclonal antisera to callous keratin (which specifically stain myoepithelial cells in the rat mammary gland).

Animals↗
PubMed1989

Characterization of human mammary cell types in primary culture: immunofluorescent and immunocytochemical indicators of cellular heterogeneity.

Parenchymal organoidal structures that were obtained from collagenase digestion of reduction mammoplasty specimens of apparently normal human breasts have been grown in short-term primary cultures, either on plastic or on floating gels of polymerized rat-tail collagen. Three morphologically distinct major cell types are readily observed in both systems: cuboidal cells, which occupy apical positions on collagen gels; larger, epithelioid, or basal cells on gels; and elongated cells which penetrate into the gel. In addition, a fourth cell type, that of large, flat cell, is observed less readily by phase contrast microscopy on the surface of cultures grown on plastic. Immunofluorescent and immunocytochemical staining of cultures on plastic or histologic sections of cultures on gels have been undertaken with antisera and other histochemical reagents that stain the different parenchymal cell types in vivo. Thus antisera to epithelial membrane antigen(s), monoclonal antibodies (MABs) to the defatted mammary milk fat globule membrane, peanut lectin, and keratin MAB LE61, which preferentially stain the epithelial cells of ducts in vivo, also stain the cuboidal/apical cells in vitro. The large, flat cells are stained intensely by the first three reagents but not by the last one. Antisera to collagen IV, laminin, fibronectin, actin, keratin MAB LP34, MABs to the common acute lymphoblastic leukemia antigen, and MAB LICR-LON-23.10, which showed enhanced staining for the ductal myoepithelial cells in vivo, also stain the epithelioid/elongated cells in vitro. However, the effect of the last four reagents is reduced considerably in most elongated cells, and MAB LP34 stains the large, flat cells intensely. Heterogeneous cells of intermediate morphologies and staining patterns between the cuboidal cells and large, flat cells are related to mammary epithelial cells. whereas the large epithelioid/elongated cells have some characteristics of myoepithelial cells, and that intermediate forms may exist in culture between the two parenchymal cell types.

Adult↗
PubMed1989

Immunocytochemical identification of cell types in human mammary gland: variations in cellular markers are dependent on glandular topography and differentiation.

Antiserum to epithelial membrane antigen and three monoclonal antibodies (MAb) to milk-fat globule membranes immunocytochemically stain only epithelial cells, whereas a fourth reacts also with myoepithelial cells in inter- and intralobular ducts of human breast. Staining with peanut lectin shows a gradual increase for epithelial cells, from little or no staining in ducts through variable staining in ductules to intense staining in secretory alveoli. Antisera and MAb to vimentin, smooth-muscle actin, MAb to the common acute lymphoblastic leukemia antigen and to a glycoprotein of 135 KD stain myoepithelial cells in main ducts, but this staining is reduced in inter- and intralobular ducts and ductules. MAb to epithelial-specific keratin 18 stain a minor population of ductal epithelial cells, the major population of epithelial cells in interlobular (ILD) and extralobular terminal ducts (ETD), and epithelial cells in a minority of ductules. In lactating glands most epithelial cells in ductules are stained, but the alveolar and myoepithelial cells are unstained. Keratin MAb PKK2 and LP34 strongly stain myoepithelial cells, but only a minor population of epithelial cells in main ducts. However, these MAb stain principally the epithelial cells in ILD, ETD, and a minority of ductules. In lactating glands most epithelial cells are stained in ductules, but the myoepithelial and not the alveolar cells are stained intensely in secretory lobules. It is suggested that the unusual staining pattern of cells found principally in the ILD, ETD, and some ductules may represent regions of growth and/or subpopulation(s) of cells intermediate between epithelial and myoepithelial cells.

Actins↗
PubMed1989

The effect of a 72-h fast on plasma levels of pituitary, adrenal, thyroid, pancreatic and gastrointestinal hormones in healthy men and women.

Seventeen human subjects fasted without electrolyte replacement for 3 days and hormone levels were measured before, during and after the fast. Immediate consequences of the fasting state in healthy human subjects include a marked increase in plasma cortisol. ACTH, beta-endorphin, beta-lipotrophic hormone, adrenaline, noradrenaline and dopamine. Levels of all these hormones were much greater on the first morning of the fast than in the post-prandial state, even though the plasma glucose level was no lower than that observed on the morning before the fast began. A clear fall in TSH and tri-iodothyronine (T3) levels was observed, but thyroxine levels did not change significantly. Insulin levels fell whereas proinsulin levels did not fall during the fast, though they did rise markedly upon re-feeding. An increase in GH levels was particularly apparent in male subjects, but was also seen in females when evening samples were compared. Pancreatic glucagon showed a modest rise during the fast, but fell again on refeeding; total glucagon also rose as the fast proceeded, but increased markedly upon re-feeding. Levels of gastrin and peptide YY remained low during the fast. Plasma electrolyte levels were unchanged. The following were closely correlated: cortisol with ACTH, T3 with log10 TSH, dopamine with noradrenaline, and (negatively, during the fast) pancreatic glucagon with glucose.

Adrenal Cortex Hormones↗
PubMed1988

Extracellular matrix control of collagen production by rat mammary epithelial and myoepithelial-like cells in vitro.

A rat mammary myoepithelial cell line (Rama 401) grown on plastic produces 5 times more collagen (largely type IV) than a mammary epithelial cell line (Rama 704) grown on the same surface. When the cells are grown on collagen gels, the amount of collagen produced by Rama 704 cells increases 3.3 times, whereas there is no increase in collagen production by Rama 401 cells. Increased production of collagen by Rama 704 cells is due to both an increased rate of synthesis and a decreased rate of degradation. These results indicate that for mammary epithelial cells, unlike myoepithelial cells, the rate of production of collagen can be regulated by the extracellular matrix.

Animals↗