M. Wells

Sensitive in situ hybridisation technique using biotin-streptavidin-polyalkaline phosphatase complex.

A sensitive in situ hybridisation technique, using a biotin-streptavidin-polyalkaline phosphatase complex detection system, was successfully applied to smears of fresh cultured cells, frozen sections, and formalin fixed paraffin processed tissue: the procedure was successful for DNA-DNA hybridizations using a variety of DNA probes. The detection method is rapid, reliable, and economical producing a purplish-blue precipitate at the site of hybridisation and clearly visible by low power light microscopy.

Maternal and fetal cellular relationships in the human placental basal plate

Maternal and fetal cellular relationships in the normal human term placental basal plate were investigated by single and double immunohistochemical labelling techniques. Extravillous fetal trophoblast in the basal plate was uniformly reactive with markers of low-molecular-weight cytokeratins. The predominant maternal leucocyte population in the basal plate consisted of leucocyte-common-antigen-positive, class II MHC-positive macrophages, which exhibited acid phosphatase activity. Double-labelling methods highlighted the close association of these macrophages with extravillous trophoblast: they often extended processes around the fetal cells and were also observed within islands of cytotrophoblast. Other leucocytes were uncommon, although aggregates of T cells were apparent in some tissues.

The human placental bed: histology, immunohistochemistry and pathology

There has been much interest recently on local intra‐uterine materno‐fetal interactions particularly in the placental bed where cellular relationships between mother and fetus are at their most intimate. While few histopathologists are expected to interpret formal placental bed biopsy specimens, confrontation with tissue from this site is common following abortion, post‐partum haemorrhage or molar gestation. This review gives an account of recent advances in our knowledge of the histology, immunohistochemistry and pathology of the placental bed. It focuses particularly on extravillous trophoblast populations and their relationship to maternal cells and emphasizes the importance of vascular changes.

Human papilloma viruses: a study of their prevalence in the normal larynx

The association of human papilloma viruses (HPV) with laryngopharyngeal squamous cell carcinoma is under investigation. The suitability of control tissue in the reported series, invariably obtained from histologically normal tissue adjacent to a squamous cell carcinoma or from patients with benign laryngopharyngeal disease, is questionable. The present study determined the prevalence of HPV in a series of normal larynges. Twelve autopsy larynges were collected. DNA was obtained by SDS proteinase K digestion. Evidence of HPV infection was documented by the polymerase chain reaction using oligonucleotide primers complementary to sequences in the E6 region of HPV types 11, 16 and 18. Four female and eight male larynges, mean age 65 years (SD = 16 years) were collected 72 hours postmortem (median value). HPV type 11 was isolated from three specimens. A 25 per cent prevalence rate for HPV 11 was found. No other HPV types were isolated.

Complement component deposition in utero-placental (spiral) arteries in normal human pregnancy

There is conflicting evidence for the deposition of complement in spiral arteries in normal and abnormal human pregnancies. The immunogold silver staining (IGSS) technique was used to investigate the distribution of C1q, C3d, C4, C6 and C9 within the spiral arteries of formalin-fixed normal pregnancy hysterectomy specimens ranging in gestational age from 4 to 40 weeks. Deposition of complement components studied was observed in all cases suggesting classical pathway activation. Reactivity was not confined to vessels showing endovascular trophoblast though the latter showed a characteristic linear deposition subjacent to the trophoblast. Reactivity was most intense for C3d and C9. An appreciation of complement deposition as a feature of normal pregnancy is essential before significant immunopathology can be recognised in placental bed vessels in abnormal pregnancy.

Diagnosis of molar pregnancy and persistent trophoblastic disease by flow cytometry.

Histopathological assessment and flow cytometric analyses were carried out on 32 placentas (representative of each trimester) and 88 molar pregnancies. Three first trimester placentas were triploid, and the remaining 29 placentas were diploid. Of the 88 cases originally diagnosed as molar pregnancies, 26 were triploid (two complete moles, 20 partial moles, and four hydropic abortions); 59 were diploid (46 complete moles, 10 partial moles, three hydropic abortions); one was tetraploid (partial mole); and two were DNA aneuploid (one partial mole, one complete mole). A significantly increased hyperdiploid fraction (a measure of cell proliferation) was detected in diploid complete moles (p less than 0.0001) and cases of persistent trophoblastic disease (p less than 0.001) when compared with diploid placentas and diploid partial moles. All seven cases of established persistent trophoblastic disease, for which follow up was available, were diploid and showed high hyperdiploid fractions within the range for diploid complete moles. These findings suggest that flow cytometric DNA measurements may be an important aid in the diagnosis of molar pregnancy. The high degree of cell proliferation found in this study may explain the premalignant potential of complete hydatidiform moles.

Subinvolution of the uteroplacental arteries in the human placental bed

Subinvolution of the uteroplacental arteries of the placental bed is a recognized cause of post partum haemorrhage causing significant morbidity. Whilst the physiological changes in these arteries during pregnancy and the part played by endovascular trophoblast migration are well documented, the sequence of events during involution and the pathophysiology of subinvolution are unknown. Using immunohistochemical techniques we have studied uteroplacental arteries in the placental bed in 25 cases of post partum haemorrhage and compared the subinvoluted vessels with normally involuted vessels. Non‐involuted vessels were present in 22 test cases; these abnormal vessels were filled with thrombus and no endothelial lining was detected. Extravillous perivascular trophoblast was usually present in the walls of these abnormal vessels and in some cases was seen in an endovascular position. Subinvolution of placental site vessels may represent an abnormal interaction between maternal uterine cells and fetal trophoblast.

Demonstration of multiple HPV types in normal cervix and in cervical squamous cell carcinoma using the polymerase chain reaction on paraffin wax embedded material.

The prevalence of human papilloma virus (HPV) types 6, 11, 16 and 18 was investigated using the polymerase chain reaction on formalin fixed, paraffin wax embedded material in 19 cases of cervical squamous cell carcinoma and in 10 normal cervices. HPV DNA was detected in 16 of 19 carcinomas, with multiple types present in 11 of these. HPV 16 or 18, or both, were present in all cases in which HPV was shown. Six of 10 cases of normal cervix contained HPV; five of these contained two or more HPV types, including HPV 16 or 18, or both. This study shows the feasibility of using the PCR on paraffin wax embedded material and indicates a high rate of carriage of multiple HPV types in both normal and neoplastic cervix.

Class I Antigens of the Major Histocompatibility Complex on Cytotrophoblast of the Human Placental Basal Plate

ABSTRACT: The lack of class I antigens of the major histocompatibility complex (MHC) on syncytiotropho‐blast has been proposed as an explanation for the survival of the allogeneic fetus. These antigens, however, have recently been detected on nonvillous trophoblastic columns of the early human placenta. By using a combination of immunofluorescence techniques to identify trophoblast, we have studied transplantation antigens of the cytotrophoblastic shell present in the basal plate of normal full‐term human placentae. With the use of two different monoclonal antibodies to a common determinant of HLA (clones W6/32 and 61D2), it was shown that this subset of trophoblast does express class 1 MHC antigens. However, while these cells reacted uniformly with W6/32, only rare reactivity with 61D2 was found. Reactivity of polyclonal antisera to β‐mi croglobulin correlated with that seen using W6/32. These results are similar to those recently observed in a subset of trophoblast of the amniochorion to which the term “metatrophoblast” has been given.

Immunohistological characterization of endometrial gland epithelium and extravillous fetal trophoblast in third trimester human placental bed tissues

Summary. The distribution, morphology and antigen expression of endometrial glands, uterine vessels and fetal trophoblast have been studied in third trimester placental bed tissues with a panel of monoclonal antibodies in immunohistochemical techniques. Residual endometrial glands were numerous but often were attenuated or compressed and could only be identified clearly with epithelial cell markers. These glands must be clearly distinguished from vessels and trophoblast in immunological studies of cells in the placental bed. The changing pattern of antigen expression of both maternal glands and fetal trophoblast in placental bed tissues may indicate a form of local regulation of gene expression.