Deborah V. Chapman

Epithelial markers in primary skin cancer: an immunoperoxidase study of the distribution of epithelial membrane antigen (EMA) and carcinoembryonic antigen (CEA) in 65 primary skin carcinomas

Sixty‐five primary malignant skin tumours have been stained for carcinoembryonic antigen (CEA) and epithelial membrane antigen (EMA) using rabbit polyclonal affinity‐purified antibodies and an indirect immunoperoxidase technique. The tumours consisted of 15 invasive squamous carcinomas, 23 basal cell carcinomas, 16 malignant eccrine poromas (porocarrinomas), and 11 sebaceous carcinomas. The basal cell carcinomas were negative for CEA and EMA except where there was keratotic or sebaceous differentiation. All the sebaceous and squamous carcinomas and 15/16 porocarcinomas contained EMA. 12/15 squamous carcinomas were positive for CEA. The malignant poromas were negative for CEA except on the ulcerated surface of two. In tumours classified as sebaceous carcinomas there was positive staining for CEA in some cells, cyst contents and/or keratotic foci. These findings have implications for the use of immunoperoxidase localization of epithelial markers in the differential diagnosis of primary and metastatic skin cancer.

The role of the cyst stage in the seasonal growth of the dinoflagellate Ceratium hirundinella within a small productive lake

Large populations of the dinoflagellate Ceratium hirundinella occur regularly in a small productive lake and their decline during September and October is normally associated with mass encystment. Evidence for the major role of benthic cysts in providing the inoculum for subsequent growth is given from morphological and quantitative studies over two contrasting years of cyst production, 1980 and 1981. For both years there were two distinct phases of population increase in the plankton. Low winter densities were followed by rapid rates of increase during February and March at the same time as empty cysts appeared in the sediment. These changes occurred when water temperatures rose from approx. 3 to 5°C. After near-stationary periods in April and May 1980 and April to June 1981 there followed phases of exponential growth but at appreciably slower rates of population increase than during recruitment from excystment. That excystment was the major contributor to the rapid vernal increase of planktonic cells is...

CYST FORMATION IN THE FRESHWATER DINOFLAGELLATE CERATIUM HIRUNDINELLA (DINOPHYCEAE)1

Cyst formation in Ceratium hirundinella (O. F. Müll.) Bergh was studied by light and electron microscopy, using material from several lakes and reservoirs and also laboratory cultures. Cells preparing to encyst build up large quantities of starch and lipid and at the same time reduce their other cell components. The cyst is released from the theca as a naked cell bounded by a double membrane. The most commonly found cyst deposits a layer of electron‐dense granules containing silicon on the outer membrane and lays down a cellulose‐like material between the two membranes. Cysts without the electron‐dense granules are commonly formed in cultures but rarely found in lakes. These cysts appear less resistant to decay and do not show the reorganization of cell contents for dormancy. It is suggested that C. hirundinella has both a resting cyst, forming part of the life cycle, and a temporary cyst stage.

Human chorionic gonadotropin and human placental lactogen in extragonadal tumors an immunoperoxidase study of ten non-germ cell neoplasms

The immunoperoxidase localization of the alpha and beta subunits of human chorionic gonadotropin (hCG) and of human placental lactogen (hPL) was studied in ten extragonadal nontrophoblastic tumors associated with raised serum levels of one or more of these placental proteins. Three of the tumors were bronchial carcinomas, one was a gastric carcinoma, two were malignant carcinoids (one bronchial and one gastric), two were pancreatic islet cell carcinomas, and two were metastatic carcinomas with an unknown primary site. The maximum alpha subunit serum level was 33,000 ng/ml (gastric carcinoid), the maximum hCG/hCG‐beta level was 705,000 ng/ml, and the maximum hPL level was 50 ng/ml (both in the gastric carcinoma). An indirect immunoperoxidase technique and rabbit polyclonal affinity‐purified antibodies and peroxidase conjugates were used on formalin‐fixed, paraffin‐embedded sections. Five blocks (eight cases) or six blocks (two cases) from various sites were obtained from each patient at surgery and/or autopsy. Positive stains for hCG/hCG‐beta were seen in six of seven tumors (25/37 blocks) with raised levels, for the alpha subunit in nine of nine tumors (30/47 blocks), and for hPL in two of five tumors (4/26 blocks). Only a relatively minor number of the cells were positive, and within the same case, there was considerable site‐to‐site variation in the number of positive cells. Large bizarre cells contained hCG/hCG‐beta as well as the alpha subunit, if it was demonstrated in the same tumor as the beta subunit. Otherwise, the alpha subunit was found in small unremarkable cells. Giant cells that were smaller than those positive for hCG/hCG‐beta contained in hPL. In some serial sections, hCG‐alpha, hCG/hCG‐beta, and hPL were segregated in different cell populations, supporting the concepts of their separate genetic control.

An electron microscope study of the excystment and early development of the dinoflagellate Ceratium hirundinella

The excystment and development of cells of Ceratium hirundinella (O. F. Mull.) Bergh. has been studied in the laboratory using transmission and scanning electron microscopy. The occurrence of an exit slit through which excystment takes place has been confirmed. The emergent cell, or gymnoceratium, is shown to lack thecal plates but has thecal vesicles with extensive microtubules lying beneath. Thecal plates rapidly form within the vesicles except in the ventral region adjacent to the chamber. The flagellar apparatus is present at the gymnoceratium stage prior to excystment, but the more extensive chamber develops with cell growth. Starch and lipid reserves are present in the gymnoceratium and throughout the cells development, and they have distinct locations within the cell. The occurrence of a pusule has been confirmed. This opens near the base of the longitudinal flagellum. The ultrastructure of the orange pigmented bodies, observed with the light microscope, is described and these are compared with th...

Immunoperoxidase techniques: the deleterious effect of sodium azide on the activity of peroxidase conjugates.

The effect of including sodium azide as a bacteriostatic agent in solutions used to dilute antibodies conjugated with the enzyme horseradish peroxidase was examined. An enzyme-linked immunosorbent assay (ELISA) and an immunohistochemical method were used and both techniques demonstrated an inhibitory effect of sodium azide on the activity of the peroxidase conjugates. It is concluded that the use of sodium azide in solutions used to dilute peroxidase conjugates is to be avoided.

The distribution of metals in sewage sludge and their fate after dumping at sea

A review of the literature concerning the distribution of toxic metals in sewage sludges suggests that in most sludge types metals are bound to small particles (⩽10 μm) consisting mostly of organic matter. Evidence for the fate of sludge particles and their associated metals after dumping at sea is conflicting. Recent work suggests much of the metal remains associated with the particles and little is lost to solution. Small, low density organic particles may take many hours to settle, although this process may be aided by flocculation. Prior to settling, organic particles are available to planktonic filter-feeding organisms, whereas the larger, denser fraction of the sludge settles more rapidly and is available to benthic organisms. Both filter-feeding groups are potentially at risk from accumulating metals from sludge dumping.

Microbiological assessment of private drinking water supplies in Co. Cork, Ireland

The microbiological quality of 75 private drinking water supply boreholes in Co. Cork, Ireland was assessed in order to determine the incidence of contamination and the potential pathways of such contamination. Microbiological analysis was carried out using the membrane filtration technique for the recovery of thermotolerant (faecal) coliforms. The sanitary protection of the supplies was evaluated by means of systematic inspections and subsequent qualitative sanitary risk assessment. Almost a quarter of all supplies investigated (24%, n = 18) was found positive for thermotolerant coliforms. Weather conditions had a significant impact on microbiological water quality, increasing both contamination incidence and gross contamination frequency. Over half of the supplies had nine or more sanitary hazards and most had rudimentary sanitary protection measures at the head of the borehole. These low sanitary protection measures suggest that boreholes can pose a significant hazard to valuable groundwater resources by providing direct contamination routes.

Interactions between marine crustaceans and digested sewage sludge

Abstract Digested sewage sludge as dumped at sea was labelled with radioactive silver which bound tightly to the particulate fraction of the sludge. Both mysids ( Schistomysis spiritus ) and barnacles ( Elminius modestus ) ingested the sludge. The silver was apparently assimilated by the barnacles. The mysids, with sludge still in their guts, were fed to shrimps ( Crangon crangon ) which subsequently accumulated the silver in the hepatopancreas. When exposed directly to the sludge suspension the shrimps accumulated fine particles in their gills and attached to the limb and body setae. Although the gills could be flushed in clean water the sludge attached to the setae was mainly lost after moulting. Moults may be ingested by the shrimps themselves or by other scavengers. Thus sludge attached to, or within, the bodies of marine organisms may provide an additional means of metal transfer from sewage sludge into marine food chains.

Intercellular canaliculi in eccrine sweat glands: an immunoperoxidase study.

Using an indirect immunoperoxidase technique, both epithelial membrane antigen and carcinoembryonic antigen were identified within the ducts and secretory coils of the eccrine sweat gland. Antibodies to epithelial membrane antigen stained the intercellular canaliculi of the secretory coils, as did those antisera to CEA which showed activity against normal cross‐reacting antigen (CEX, NCA). Those without such activity showed minimal or no staining of intercellular canaliculi. There is a difference in antigenic expression between the acinar cells and their intercellular canaliculi, and the cells of eccrine ducts.