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Biomedical subjects

R Penketh

Publications and source records attributed to R Penketh.

14 recordsLinked to original sources
PubMed1999

Laparoscopic management of benign ovarian disease.

There was little controversy in the management of ovarian cysts until 15 years ago when operative endoscopy gained popularity. Before this time, laparotomy was the standard form of treatment for pelvic masses. Simple cysts were treated laproscopically by aspiration and solid or large tumors with any malignant potential by laparotomy. Constantly improving technology and instrumentation has allowed more and more operations to be performed laparoscopically. The gynecological oncologist has been wary of adopting this form of surgery for potential gynecological malignancies because of the safety and efficacy issues. Pelvic pathology, particularly ovarian tumors, pose a difficult problem. Apart from difficulty in screening, it is also difficult to confirm the nature of an ovarian pathology using the currently available investigative modalities. If the nature of an ovarian cyst can be ascertained beyond doubt, then the treatment can be simple, laparoscopy for benign and laparotomy for malignant. Having said that, more enthusiastic operative laparoscopists are using this approach to treat gynecological malignancies. We discuss the role of laparoscopy in the management of ovarian cysts.

Female↗
PubMed1990

The intracardiac neurones of the fetal human heart in culture.

Dissociated cell culture preparations were employed to study intracardiac neurones of the atria from human fetal hearts at 9 to 21 weeks' gestation. Intracardiac neurones were not observed in cultures dissociated from the ventricles. Single neurones, as well as groups, could be identified by phase-contrast microscopy in all of the atrial cultures prepared from 14 to 21 weeks' gestation, and protein gene product 9.5-like immunoreactive neurones were detected in cultures from as early as 10 weeks' gestation. The neurones were mononucleate, with a prominent nucleolus or multiple nucleoli, and often had extensive neurites. Neurones tended to be bigger in cultures from later stages in gestation, and these cells appeared to be more mature with a complex pattern of neurite outgrowth. Many neurones from 15 to 20 weeks' gestation expressed somatostatin-like immunoreactivity in culture. A very low proportion of cultured neurones was immunoreactive for neuropeptide Y and its C-terminal flanking peptide. Neuropeptide Y-like immunoreactive neurones also contained 5-hydroxy-tryptamine-like immunoreactivity in culture, but dopamine beta-hydroxylase-like immunoreactive neurones were not detected. This study is the first description of human intracardiac neurones in culture and forms the essential baseline for further direct investigation of these cells.

Axons↗
PubMed1990

Immunocytochemical studies of cardiac myocytes and other non-neuronal cells of the fetal human heart in culture.

Non-neuronal cell types present in cultures dissociated from the atria and ventricles of human fetal hearts, from 9 to 21 weeks' gestation, were studied using phase-contrast optics and immunocytochemistry. All atrial myocytes and many, if not all, ventricular myocytes observed in culture contained atrial natriuretic peptide-like immunoreactivity. Generally, the atrial natriuretic peptide-like immunoreaction in atrial myocytes was more intense and widespread than in ventricular myocytes. Atrial and ventricular fibroblasts expressed extracellular fibronectin-like immunoreactivity. A population of cells with the appearance and growth properties of endothelial cells was observed in both atrial and ventricular cultures, and was classified as endothelioid since their precise origin was not known. Only a subpopulation of these endothelioid cells contained factor VIII-related antigen immunoreactivity, and some cells that did not display the other growth characteristics of endothelial cells were also factor VIII-related antigen immunoreactive in culture. Glial cells were S-100-like immunoreactive; they were usually more numerous in atrial than ventricular preparations. There was no close association between glial cells and neurones in the atrial cultures.

Atrial Natriuretic Factor↗
PubMed1990

Myocardial localization and isoforms of neural cell adhesion molecule (N-CAM) in the developing and transplanted human heart.

Neural cell adhesion molecule (N-CAM) has been implicated in cellular interactions involved in cardiac morphogenesis and innervation. Immunohistochemical techniques and Western blot analysis were used to determine the localization and isoforms of N-CAM in the developing and extrinsically denervated human heart. Myocardial and conducting cells in the fetal heart (7-24 wk gestation) exhibited sarcolemmal immunoreactivity, the major desialo N-CAM isoforms being 150, 145, 120, 115, and 110 kD. N-CAM expression appeared to be downregulated in the myocardium during adult life, with relatively little sarcolemmal immunoreactivity being detected in normal donor tissues. In contrast to the temporal changes observed in the myocardium, both the developing and mature cardiac innervation displayed N-CAM immunofluorescence staining, localized to neuronal cell bodies, nerve fascicles and fibres. Extrinsically denervated cardiac allografts, obtained 2 d to 91 mo after transplantation, showed extensive sarcolemmal and intercalated disc immunostaining and expression of 125-, 120-, and 115-kD isoforms. Tissues from explanted recipient hearts and atrial appendage samples obtained during coronary bypass graft operations were also examined and displayed varying amounts of N-CAM immunoreactivity. We conclude that the expression of N-CAM immunoreactivity and isoforms in the human heart is developmentally regulated and may be modulated by factors such as cardiac innervation and myocardial hypertrophy.

Adult↗
PubMed1988

Localisation of mRNA and co-expression and molecular forms of GRP gene products in endocrine cells of fetal human lung.

The presence of bombesin (gastrin-releasing peptide, GRP)-like immunoreactivity in mucosal endocrine cells of human fetal lung is well established. In this study we have investigated the localisation of pro-GRP mRNA and GRP gene products and compared the distribution and levels of extractable GRP- and C-terminal flanking peptide of human pro-GRP-like immunoreactivity in order to verify synthesis and to investigate their coexistence and molecular forms. Human fetal lungs (14 to 23 weeks gestation) were immunostained, and extracts were assayed using region-specific antisera to pro-GRP. Additional antisera to chromogranin and protein gene product 9.5 (PGP 9.5) were used for immunostaining by the peroxidase anti-peroxidase technique and for double immunofluorescence staining using antisera raised in two species. Immunoreactivity for both bombesin (GRP) and flanking peptide was seen mainly in the same endocrine cells, but more cells were stained with antisera to flanking peptide than with antiserum to bombesin (GRP). In situ hybridisation showed that pro-GRP mRNA was present and thus synthesis of the peptides was taking place. Endocrine cells and nerve fibres were PGP 9.5-immunoreactive, and a subset of cells was immunoreactive for bombesin gene products. Radioimmunoassay and chromatography show that pro-GRP is present in both the uncleaved and cleaved forms, and, in agreement with immunocytochemistry results, that an excess of C-terminal peptide of pro-GRP is detectable. It is therefore concluded that GRP-like peptides and flanking peptide are co-localised in human pulmonary endocrine cells, but the latter is found in larger concentrations than free GRP. Thus GRP-like peptides may be secreted separately from the flanking peptide(s) of pro-GRP.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromatography, Gel↗
PubMed1987

Prenatal diagnosis in the human pre-implantation period. Meeting held at the Ciba Foundation on the 13th November 1986.

There is a clinical need for prenatal diagnosis before implantation for patients at high genetic risk who are unable to face the uncertainty of a pregnancy associated with conventional diagnostic methods, as well as for IVF patients who are at high risk for genetic or chromosomal anomalies. Research on human pre-embryos is required to establish: biopsy techniques during cleavage and at the blastocyst stage, in-vitro viability after biopsy, the culture potential of cells removed at these stages, cryopreservation of biopsied pre-embryos, and diagnostic procedures on biopsy material. The consensus view was that blastocyst biopsy is the most likely to succeed. The possibility should be considered of obtaining blastocysts by uterine lavage for diagnostic purposes in fertile women at high genetic risk. However it would be unethical to use uterine lavage to obtain blastocysts for research purposes. Rapid methods of typing the embryos the avoid the need for cryostorage, but there was a consensus (among those on the laboratory diagnostic side) that cryostorage would relieve some of the pressure of the ongoing diagnosis, and allow unhurried detailed analysis. All those present agreed that there is a need for further scientific research to establish pre-implantation diagnosis as a clinical reality. Close collaboration between workers in the fields represented will be necessary to achieve this goal.

Animals↗