Search PubMed⌕ Search

Biomedical subjects

D Royston

Publications and source records attributed to D Royston.

At least 73 records · Page 4Linked to original sources
PubMed1994

Human endocardial innervation and its relationship to the endothelium: an immunohistochemical, histochemical, and quantitative study.

OBJECTIVE: The endocardium contains an extensive neural plexus, the composition and function of which are unclear. The aim of this study was to characterise the innervation of the endocardium in terms of the relative density and distribution of its autonomic and sensory nerve subpopulations and to assess the relationship between these nerves and endocardial endothelial cells. METHODS: Immunohistochemical, histochemical, confocal, and quantitative image processing techniques were applied to whole mount preparations of human postmortem endocardium obtained within 24 h of death. RESULTS: The overall distribution of nerve fibres and fascicles was demonstrated using antisera to the general neural marker protein gene product 9.5 (PGP 9.5). Nerves displaying acetylcholinesterase activity represented the main nerve subpopulation, occupying 9-18% of the quantified field area. Neuropeptide Y immunoreactive nerves formed the most numerous peptide containing nerve subpopulation identified, occupying 5-19% and 2-7% of the field area in the ventricle and atrial endocardium respectively and having similar distribution patterns to tyrosine hydroxylase immunoreactive nerves. Nerves showing immunoreactivity for somatostatin, vasoactive intestinal polypeptide, and substance P were detected at a lower density, occurred more frequently in the ventricular than atrial endocardium, and showed a similar distribution in the right and left sides of the heart. Combined peptide immunofluorescence and acetylcholinesterase staining, of the same preparation, indicated that putative sympathetic and sensory nerve subpopulations could be distinguished from presumed parasympathetic, acetylcholinesterase positive, nerves. The relationship between immunostained nerves and endothelial cells was assessed using confocal microscopy. Varicose nerve fibres were detected within 0.2 micron of overlying endothelial cells in the right ventricle and between 0.4-0.6 micron in the left ventricle. CONCLUSIONS: The heterogeneous population of nerve fibres demonstrated in the human endocardium may influence the known interaction between endocardial endothelial cells and the myocardium.

Adolescent↗
PubMed1994

A comparative analysis of grading systems in renal adenocarcinoma.

While the histological grade of a renal cell carcinoma is of prognostic significance there is poor concordance amongst pathologists in the use of these grading systems. Many grading systems have been described, but none has achieved widespread acceptance. The objective of this study was to assess the degree of interobserver variation amongst four experienced pathologists in their use of four commonly applied grading systems. The pathologists reviewed a series of 88 cases of renal cell carcinoma. Grades were detailed on a proforma which consisted of a breakdown of each grading system. Cohen's kappa was calculated for each pair of observers for each system. The mean kappa scores for each system were compared using the Tukey honestly significant differences method. Mean kappa was highest for the grading system of Syrjanen and Hjelt and this grading system also had a higher mean kappa than two of the other systems tested. The most striking feature of the results was the degree to which the pathologists differed in their assessments. The grading system of Syrjanen and Hjelt was shown to be subject to less interobserver variability than other commonly used classifications and we are of the opinion that it should become the standard method.

Adenocarcinoma↗
PubMed1994

Innervation of the human cardiac conduction system. A quantitative immunohistochemical and histochemical study.

BACKGROUND: Cardiac conduction is influenced by peptidergic mechanisms as well as classic neurotransmitters. The distribution of peptide-containing nerves has not been well defined. METHODS AND RESULTS: Immunofluorescence and histochemical techniques were used to visualize the innervation of the human conduction system and to distinguish nerve subpopulations according to their peptide and enzyme content. Nerve fibers and fascicles displaying immunoreactivity for protein gene product 9.5 (PGP 9.5) were more numerous in the sinus and atrioventricular nodes than in the penetrating bundle, bundle branches, and adjacent myocardium. The relative density of innervation was greater in the central region of the sinus node than in the peripheral regions. Nerve densities were also higher in the transitional region of the atrioventricular node compared with its compact region. Acetylcholinesterase (AChE)-positive nerves were the main subtype identified in the sinus and atrioventricular nodes, representing half to two thirds of the stained area occupied by PGP 9.5-immunoreactive nerves. Neuropeptide Y-immunoreactive nerves represented the main peptide-containing subpopulation and occurred throughout the conduction system, displaying a similar pattern of distribution and relative density to those demonstrating tyrosine hydroxylase immunoreactivity. Nerve fibers showing immunoreactivity for vasoactive intestinal polypeptide, somatostatin, substance P, or calcitonin gene-related peptide exhibited distinct patterns of distribution and comprised a relatively minor component of the innervation, the percentage of stained area being 10- to 40-fold lower than that occupied by neuropeptide Y- and PGP 9.5-immunoreactive nerves, respectively. CONCLUSIONS: The innervation of human conduction tissues exhibits significant regional variation and comprises putative parasympathetic nerves and intrinsic neurons (AChE positive), sympathetic efferent nerves (neuropeptide Y- and tyrosine hydroxylase-immunoreactive nerves), and other peptide-containing nerves, some of which (substance P and calcitonin gene-related peptide containing) are considered to represent afferent nerves. Locally released peptides may be involved in the neural modulation of the human conduction system.

Acetylcholinesterase↗
PubMed1993

Fine needle aspiration biopsy of lymph nodes and subcutaneous masses.

The results of fine needle aspiration biopsy of lymph nodes and subcutaneous masses in 169 patients and the technique used are discussed. Of the 169 cases 76 were classified as cytologically malignant, 52 as benign/inflammatory and 49 as inadequate. Neck masses were most commonly sampled. The overall diagnostic accuracy achieved was 75%. No false positive and 2 false negative cases were seen. The advantages and limitations of the procedure are discussed as well as some of the possible sources of error.

Biopsy, Needle↗
PubMed1993

Aprotinin therapy in cardiac operations: a report on use in 41 cardiac centers in the United Kingdom.

Aprotinin, a serine protease inhibitor, has recently been shown to reduce blood loss in cardiac surgical patients. Data on the safety and efficacy of aprotinin therapy administered to 671 cardiac surgical patients in 41 United Kingdom cardiac surgical units have been submitted to interim analysis. The patients studied were in high-risk categories for excessive bleeding, including 457 redo operations and 79 patients with active infective endocarditis. Overall mortality was 12% in redo cases and 5.1% in first-time operations. Adverse events were reported in only 20 patients (3%). Median blood loss at 24 hours after operation was 400 mL, and median transfusion volume throughout the operative and postoperative period was 2 units. These data confirm that the use of aprotinin therapy in high-risk cardiac surgical patients is associated with a low incidence of adverse events.

Adolescent↗
PubMed1993

A comparison of two systems for assessing cerebral venous oxyhaemoglobin saturation during cardiopulmonary bypass in humans.

The Somanetics Invos 3,100 cerebral oximeter is a new noninvasive device which measures the regional oxygen saturation of haemoglobin within the cerebral microvasculature by infrared spectroscopy. It was used in nine patients undergoing elective cardiac surgery and its results were compared with measurements of jugular venous bulb saturations obtained by the Oximetrix Opticath oximetry system. The index value of jugular venous bulb saturation was obtained by analysis of jugular bulb blood in an Il282 cooximeter. The cerebral oximeter was less accurate and precise (standard deviation of difference 14.1%) than the Oximetrix system (standard deviation of the difference 2.65%) and also demonstrated a systematic error in bias unrelated to cerebral perfusion pressure. The cerebral oximeter may therefore be less useful than jugular venous bulb saturation in the clinical management of patients undergoing cardiopulmonary bypass.

Adult↗
PubMed1993

Comparison of monoclonal antibodies AUA1 and BER EP4 with anti-CEA for detecting carcinoma cells in serous effusions and distinguishing them from mesothelial cells.

Commercially available monoclonal antibodies AUA1, BER EP4 and carcinoembryonic antigen (CEA) were applied to cell blocks from 95 serous effusions. AUA1 and BER EP4 were reactive with 89% of effusions known to contain carcinoma cells, and anti-CEA with 71%. They also reacted with cells in two effusions from patients with malignant disease which were regarded as negative on conventional cytological examination of Papanicolaou-stained smears. They were negative in all but one of the benign effusions. Using all three antibodies, 95% of effusions containing carcinoma cells were detected. Use of these antibodies could improve the cytological diagnosis of serous effusions.

Antibodies, Monoclonal↗
PubMed1992

Aprotinin does not inhibit the release of PGI2 or vWF from cultured human endothelial cells.

The release of prostacyclin (PGI2) and von Willebrand factor (vWF) from human umbilical vein endothelial cells (HUVEC) was examined to determine if aprotinin had any effects on these endothelial cell reactions. These end-points were chosen to indicate if this serine protease inhibitor caused alterations in the control of haemostatic function by endothelium, in the light of the improvement in haemostasis seen in patients given aprotinin therapy at the time of open heart surgery. Stimuli used to promote secretion of prostacyclin and vWF were human alpha-thrombin, histamine, protamine sulphate, poly-L-lysine and phorbol myristate acetate. Aprotinin (30 microMs) had no significant effect on the basal or stimulated release of PGI2 or vWF from HUVEC.

Aprotinin↗
PubMed1992

Aprotinin inhibits platelet adhesion to endothelial cells.

Studies were conducted to assess the effect of the serine protease inhibitor aprotinin on platelet adherence to both thrombin-stimulated and unstimulated human umbilical vein endothelial cells. Aprotinin treatment reduced significantly the adherence of platelets to endothelium pretreated or not with thrombin. In addition, aprotinin similarly reduced the adherence of platelets to plastic or collagen-coated tissue culture wells suggesting that the main site of action of the drug in this system is on the platelets. The role of endothelium-derived relaxing factor (EDRF; nitric oxide) in these platelet-endothelium reactions was investigated by prior incubation of both platelets and endothelial cells with NG-monomethyl-L-arginine (L-NMMA) which prevents the production of nitric oxide. The results demonstrated that nitric oxide was a significant inhibitor of the thrombin-induced platelet adherence in this assay system. Treatment with aprotinin in the presence or absence of L-NMMA reduced adherence of platelets to equivalent levels suggesting that aprotinin acts directly on the platelets via a mechanism that is EDRF-independent, to inhibit adherence.

Aprotinin↗
PubMed1991

Suture technique affects perianastomotic colonic crypt cell production and tumour formation.

Suture line recurrence is an important cause of failure after potentially curative resection for colonic carcinoma. Our aim was to determine whether suture technique affected the incidence of perianastomotic tumours in experimentally induced colonic cancer. Sprague-Dawley rats were randomized into three groups. A 1 cm longitudinal colotomy was repaired with four interrupted 6/0 polypropylene monofilament sutures, using either a transmural technique (n = 18) or a seromuscular technique (n = 18). Control animals (n = 18) had a sham laparotomy. All animals received nine, weekly, subcutaneous injections of azoxymethane (total dose 90 mg/kg) starting 6 weeks after laparotomy. Surviving animals were killed 32 weeks after laparotomy. Five animals from each group were given intraperitoneal bromodeoxyuridine (100 mg/kg) 1 h before being killed. At death, perianastomotic tumours occurred more frequently in animals with transmural sutures than in either controls or those with seromuscular sutures. This difference was associated with a greater mucosal bromodeoxyuridine crypt cell labelling index in the transmural suture group. We conclude that a transmural anastomotic suture technique promotes the development of experimental perianastomotic colonic tumours.

Anastomosis, Surgical↗
PubMed1990

Propofol for long-term sedation in the intensive care unit. A comparison with papaveretum and midazolam.

Thirty-seven patients with a wide range of illnesses were studied during mechanical ventilation of the lungs in an intensive care unit. Fifteen were sedated with a continuous propofol infusion, with analgesia provided by bolus doses of papaveretum. Twelve received a continuous infusion of papaveretum, supplemented by bolus doses of midazolam. The level of sedation was assessed every four hours and measurements were made of haemodynamic and respiratory variables. Levels of sedation were generally satisfactory in both groups. Six patients who received propofol required the use of muscle relaxants, because of their strong respiratory drives, to achieve synchronisation with the ventilator. There was no significant difference in respiratory or haemodynamic variables between the groups, but several patients required inotropic support because of their disease. There was no evidence of inhibition of adrenal steroidogenesis in the propofol group. Propofol can be a useful sedative agent in the intensive care unit, but sedative regimens should be tailored to individual patient requirements.

Adolescent↗