Search PubMed⌕ Search

Biomedical subjects

D J Laurence

Publications and source records attributed to D J Laurence.

At least 19 recordsLinked to original sources
PubMed1990

The epidermal growth factor. A review of structural and functional relationships in the normal organism and in cancer cells.

The article is a review of recent knowledge of the structural relationships of epidermal growth factor (EGF) with other biological products occurring in a wide range of animal species and some viruses. The place of EGF and related products in the physiology of the whole organism is discussed against this background. Special attention is given to the role of EGF as a tissue growth factor and to the participation of related products in cancer.

Amino Acid Sequence↗
PubMed1985

Automated screening of cervical smears using immunocytochemical staining: a possible approach.

A preliminary analysis was undertaken to ascertain whether a Leitz TAS (Texture Analyse System) video camera system, which is computer controlled, could be used to detect abnormal cells in cervical smears. Immunocytochemical together with haemalum nuclear staining was used for the epithelial membrane antigen. It was possible to detect abnormal cells in routinely prepared smears taken from patients with various degrees of cervical neoplasia, including the earliest stages, but metaplastic cells were not detected by the system. Smears from patients assessed as normal by routine cytology gave a low incidence of positive results due to occasional overlapping of cells or the presence of air bubbles. This system seems to offer a new possibility for rapid automated cytometry of cervical smears.

Antibodies, Monoclonal↗
PubMed1983

The detection and evaluation of human tumor metastases.

Many biochemical indices are purported to have clinical utility in the detection and management of neoplasia. Experience gained during the past decade tends to indicate their having a more important role in the detection and monitoring of metastases than of the primary lesion. From this present review of some of the commoner human tumours, it is concluded that such marker substances are important adjuncts in the management of germ cell and certain endocrine and endocrine-related tumours. The carcinoembryonic antigen (CEA) provides a marker for many gastrointestinal cancers, but there are no presently available substances with clinical usefulness for either breast or lung neoplasms. Alternative approaches to the detection of metastases are also presented. The particular use of antibody probes at an immunohistochemical level has been claimed to be able to detect micrometastastic disease in bone marrow or tumour-related monoclonal antibody probes may have application to other cancers in the future.

Breast Neoplasms↗
PubMed1982

Isolation and characterization of two individual glycoprotein components from human milk-fat-globule membranes.

Two individual glycoprotein components from human milk-fat-globule membranes (MFGM) has been purified by selectively extracting the membrane glycoproteins followed by lectin affinity chromatography and gel filtration on Sephadex G-200 in the presence of protein-disaggregating agents. The purified glycoprotein components, termed 'epithelial-membrane glycoprotein' (EMGP-155 and EMGP-39) have estimated molecular weights of 155 000 and 39 000 respectively, and yield a single band under reducing conditions on sodium dodecyl sulphate/polyacrylamide gel. EMGP-155 and EMGP-39 contain 21.0% and 7.0% carbohydrate by weight, with fucose (13.5%, 12.4%), mannose (3.7%, 6.2%), galactose (28.5%, 22.6%), N-acetylglucosamine (17.8%, 7.4%) and sialic acid (36.4%, 51.4%) of the carbohydrate moiety respectively. For both the glycoprotein components, aspartic and glutamic acid and serine are the major amino acid residues.

Amino Acids↗
PubMed1981

Isolation and characterization of a major glycoprotein from milk-fat-globule membrane of human breast milk.

A major periodate--Schiff-positive component from milk-fat-globule membrane of human breast milk has been purified by selectively extracting the membrane glycoproteins, followed by lectin affinity chromatography and gel filtration on Sephadex G-200 in the presence of protein-dissociating agents. The purified glycoprotein, termed epithelial membrane glycoprotein (EMGP-70), has an estimated mol.wt. of 70 000 and yields a single band under reducing conditions on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The glycoprotein contains 13.5% carbohydrate by weight, with fucose, mannose, galactose, N-acetylglucosamine and sialic acid 17.2, 17.0, 21.1, 7.9 and 36.6% respectively of the carbohydrate moiety. Aspartic and glutamic acid and serine are the major amino acid residues.

Amino Acids↗
PubMed1980

A dose interpolation routine for multiple dilutions in radioimmunoassay.

A method of estimating doses from multiple dilutions of an unknown sample in radioimmunoassay is described. It uses a computer program to minimise the root mean square error about a standard curve. The confidence limits of the estimates were evaluated from the sum of squares error as a function of dose. An attached subroutine reported and suppressed points in the data set that showed unexpectedly large errors of fit. The program agreed well with an alternative point-by-point evaluation for most practical data but also responded robustly to errors at the limits of the assay curve. By studying patterns of point rejection, it is possible to build up information about the relation between the standard curve parameters and those in the unknown sets. The method is illustrated by studies of laboratory-based materials and by an assay of alphafetoprotein in samples of body fluids.

Adrenocorticotropic Hormone↗
PubMed1978

Antibodies to lactalbumin interfere with its radioimmunoassay in human plasma.

Two radioimmunoassays for human lactalbumin have been established using a rabbit antiserum. One assay uses a second antibody to separate bound from free label; the other uses polyethylene glycol to precipitate gamma globulin non-specifically. We have confirmed that about half the normal human population have a substance in their blood which inhibits the binding of lactalbumin to the rabbit antibody. Comparison of the two assays has demonstrated that this material is not lactalbumin but a naturally occurring antibody. We have shown that it is in the IgG fraction of human plasma and is probably a cross-reacting antibody to bovine lactalbumin. None out of fifteen males and fourteen out of fifty eight non-pregnant, non-lactating females had low levels of lactalbumin in the their blood (0.6--2.0 ng/ml). Our assay could not detect a statistically significant difference between normal women and those with either benign breast disease or metastatic mammary carcinoma.

Animals↗
PubMed1978

The monitoring role of plasma CEA alone and in association with other tumor markers in colorectal and mammary carcinoma.

During the past decade, evidence has accumulated to show that most, if not all, human tumors produce a variety of different factors which, if they pass into the blood and/or urine, may serve as tumor index substances (tumor markers).7 Tumor markers may either be: 1) tumor-derived--i.e., produced by the tumor itself, or 2) tumor-associated--i.e., produced by other tissues in response to the presence of the tumor and its local or distant effects on that tissue. Examples of this latter category include the changes in urinary hydroxyproline output in patients with bone metastases or the altered levels of serum acute phase proteins in neoplasia in general.7 Tumor-derived markers may be produced by either the tumor cell population itself, e.g., CEA, alpha-fetoprotein (AFP), and other oncofetal antigens, inappropriate hormones such as ACTH etc., or by their supporting framework (stroma), e.g., the osteolysins of human breast cancer.3

Breast Neoplasms↗
PubMed1977

Biochemical markers in human breast cancer.

Nineteen biochemical parameters, most of which have been individually advocated as tumour-index-substances for breast cancer, were measured in 51 patients with breast disease, 42 of whom had active breast cancer. Seven of these parameters were raised in more than half of the 17 patients of the series with overt metastases; these were serum ferritin (88%), C-reactive protein (87%), carcinoembryonic antigen (81%), acid glycoprotein (75%), total alkaline phosphatase (64%), sialyl transferase (56%), andthe urinary hydroxyproline/creatinine ratio (73%). The incidence of biochemical abnormalities in patients in this group compared favourably with the results of physical methods of detecting metastases. 7 of 16 further patients without evidence of distant metastases, but who had a poor prognosis as judged by histology of the primary tumour and axillary lymph-nodes, had abnormalities of at least one of the seven parameters. 3 of these patients have relapsed within a year of mastectomy. The results suggest that these biochemical tests could assist in monitoring metastatic disease and could indicate at the time of mastectomy, patients who might benefit from immediate systemic therapy in addition to local treatment of their breast carcinomas.

Adenofibroma↗
PubMed1975

First British standard for carcinoembryonic antigen (CEA).

In 1974, the National Institute for Biological Standards and Control (NIBSC) established the first British Standard for carcinoembryonic antigen (CEA) for use in comparative quantitative assays. The Standard, which was prepared for material processed by the Chester Beatty Research Institute, is in the form of a freeze-dried powder, sealed in all glass ampoules code labelled 73/601 and containing pure dry nitrogen. For practical purposes, each ampoule contains 100 units of CEA activity.

Amino Acids↗
PubMed1975

Human tumour-associated and tumour-specific antigens: some concepts in relation to clinical oncology.

The concept of tumour-specific antigens is constantly undergoing reappraisal with the development of more sensitive methods for their detection. This has resulted in the finding that the many 'new' antigens produced by human tumours or materials immunologically closely related to them are also present in non-neoplastic tissues, albeit in small amounts. However, other antigens still appear to exist almost entirely in or on tumour cells so that the antigens of human tumours may be subdivided into either tumour-associated macromolecules or tumour-specific antigens. The elucidation of the chemical nature of the tumour-specific antigens may result in important advances in cancer diagnosis and therapy. As many are organ specific, it should be possible to evolve test systems which will enable tumours to be diagnosed and located before they become apparent clinically. On the other hand the tumour-associated macromolecules, of which the oncofetal antigens are the principal examples, are found in elevated amounts in some non-neoplastic disorders. It is now clear that serial estimation of the levels of these macromolecules is of considerably more diagnostic value than single random measurements. Current work is establishing their value in the detection of recurrent and metastatic tumours before they become apparent by other methods, which is probably their most important role, and also their value as aids to monitor therapeutic efficacy. The future use of both types of antigen may unfold a new era in cancer detection and therapy but many basic chemical and immunological studies are needed before their clinical use can be fully defined.

Antigens, Neoplasm↗
PubMed1974

Role of serial plasma C.E.A. assays in detection of recurrent and metastatic colorectal carcinomas.

Serial estimations of plasma carcinoembryonic antigen (C.E.A.) levels have been carried out in 220 patients with colorectal carcinomas who had potentially and apparently curative surgery. In a two-year follow-up period 53 patients developed recurrences or metastases. In 36 of these patients sustained rises in plasma C.E.A. titres occurred synchronously with or between three and 18 months before the clinical detection of recurrences or metastases. The use of serial plasma C.E.A. assays is therefore recommended as an additional diagnostic aid for the earlier detection of recurrent or metastatic colorectal carcinomas.

Bone Neoplasms↗