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Biomedical subjects

J Easton

Publications and source records attributed to J Easton.

At least 37 records · Page 2Linked to original sources
PubMed1989

Secretion of antidiuretic hormone in neurosurgical patients: appropriate or inappropriate?

In neurosurgical patients with hyponatraemia (plasma sodium less than 130 mmol/l) and natriuresis, increased antidiuretic hormone (ADH) secretion may be appropriate rather than inappropriate. Ten such patients were studied prospectively to assess circulating ADH concentration and body fluid volumes. Compared with a control group, the mean plasma ADH level was significantly elevated (0.9 pmol/l (s.e.m. = 0.2) versus 0.2 pmol/l (s.e.m. = 0.1], the total body water was normal (101% (s.e.m. = 3) versus 100% (s.e.m. = 6], while the blood volume was significantly reduced (89% (s.e.m. = 3) versus 104% (s.e.m. = 5]. The elevated ADH level was therefore appropriate to a reduced blood volume. This suggests that, in neurosurgical patients with hyponatraemia, fluid restriction could be dangerous. Serial observations in this small group of patients showed that salt replacement and normal fluid intake resulted in a fall in the elevated ADH levels.

Acute Disease↗
PubMed1988

A method for the preparation of mononuclear cells devoid of platelet contamination and its application to the evaluation of putative alpha-receptors in normal and asthmatic subjects.

Receptor studies of human mononuclear leukocytes (MNLs) are complicated by the presence of contaminating platelets which have common receptors. A method was devised to produce MNLs free of platelets (less than 1%) and consists of sequential Ficoll-Hypaque gradients, a BSA gradient and a washing step. Lack of platelet contamination was confirmed by the following criteria: (a) microscopic evaluation using fluorescent dyes showed less than 1% platelets; (b) PGE1 stimulation of the leukocyte membrane adenylate cyclase required addition of exogenous GTP while the platelet cyclase did not; (c) immunoblots of the cells and membranes using antibodies strongly reactive against platelet membranes showed no reactivity against MNL membranes; (d) [3H]yohimbine showed no binding in MNL membranes under conditions where substantial binding to platelets was detected. MNLs were viable as judged by dye exclusion. PHA stimulation of lymphocytes was unimpaired. Plasma membranes of MNLs were prepared by brief sonication and fractionation on a sucrose step gradient. Binding studies using 3H-DHE, an alpha-receptor ligand, revealed no binding in MNLs from normal subjects (n = 6). By contrast, studies on cells from subjects with mild asthma with medication appropriately withheld (n = 8) showed low levels of binding (60-300 fmol/10(6) cells). The subtype and functionality of the putative alpha-receptors are being further evaluated.

Adenylyl Cyclases↗
PubMed1988

Communication aids.

Explore the source record for details and available documents.

Communication Devices for People with Disabilities↗
PubMed1988

Macroglossia and posterior fossa disease.

We describe five cases of macroglossia in patients with posterior fossa disease and suggest that the primary mechanism is neurogenically determined rather than one of vascular obstruction or local trauma.

Adult↗
PubMed1988

Epstein-Barr virus serology in the control of nasopharyngeal carcinoma.

Epstein-Barr virus (EBV) is suspected as being etiologically related to nasopharyngeal carcinoma (NPC). Antibodies to EBV antigens have been used in the early detection of NPC and serologic assays are being utilized in the mass screening of high risk populations. While areas of potential application to disease control, such as therapy, are still in the developmental phase, EBV serology has been reported to be of value in the detection of early relapse. Since the data from a series of studies provide conflicting results, however, in this report we review the current information regarding detection of early relapse and describe specific areas that require particular attention if the role of EBV serology in this aspect of NPC control is to be well defined.

Antigens, Viral↗
PubMed1983

The distribution of thoracic glomus tissue (aortic bodies) in the rat.

An inventory of the distribution of thoracic glomus tissue (thoracic chemoreceptor tissue, aortic bodies) has been derived from serial sections in foetal, newborn and adult rats. In contrast to other common experimental species, such as the cat and dog, aortic bodies are an inconstant feature and, on the whole, are scarce in the rat. These morphological findings correlate well with experimental studies, indicating an absence or paucity of thoracic chemoreceptor activity in the rat. The results are discussed in terms of their physiological and pathophysiological implications and a revised model of the peripheral arterial chemoreceptor system is presented.

Animals↗
PubMed1981

The reliability of IgA antibody to Epstein-Barr virus (EBV) capsid antigen as a test for the diagnosis of nasopharyngeal carcinoma (NPC).

Since patients with nasopharyngeal carcinoma were first reported to have elevated levels of IgA antibody to Epstein-Barr virus (EBV) in their sera, workers in a number of countries have studied the possibility that this assay could be used in the diagnosis and monitoring of patients with this disease. In the United States, a collaborative project involving seven centers has been established to investigate the potential value of IgA antibody to EBV viral capsid antigen (VCA) as a clinical tool. In this report, we will summarize the results obtained from three studies: a comparison of EBV serology in three laboratories; a retrospective study of 37 nasopharyngeal carcinoma (NPC) patients and controls, and a prospective study of 126 NPC patients and 683 controls, including 149 patients with other malignancies involving the head and neck. The study of testing comparability in three laboratories demonstrated the feasibility of using this assay in a number of laboratories. The retrospective study confirmed the difference in IgA antibody titers between NPC patients and matched controls. The prospective study showed a relationship between IgA antibody titers and histopathology but not disease stage. IgA antibody titers were elevated more frequently in patients with nonkeratinizing or poorly differentiated types of NPC than for the well-differentiated squamous cell carcinomas. While IgA antibodies to EBV VCA appear to be of value in the early detection and diagnosis of NPC, it is possible that additional serologic tests for immunity to EBV, such as IgG antibody to VCA or early antigen (EA), will improve even further the clinical value of EBV serology in the management of NPC.

Antibodies, Viral↗
PubMed1978

Experimental infection of Callithrix Jacchus marmosets with Herpesvirus ateles, Herpesvirus saimiri, and Epstein Barr virus.

We inoculated common marmosets (Callithrix Jacchus) with Herpesvirus ateles (HVA), Herpesvirus saimiri (HVS), and Epstein-Barr virus (EBV). HVA-induced tumors contained several cell types, including giant cells reminiscent of the Sternberg-Reed cells observed in human Hodgkin's disease. HVS and EBV did not induce tumors, although HVS was present in lymphocytes and elicited a strong antibody response. EBV elicited only a variable antibody response. We feel that more common marmosets should be used to determine if the pathologic and immunologic lesions caused by HVA would be a suitable animal model for Hodgkin's disease and/or other malignant lymphomas of man. Inconsistency in the induction of tumors by EBV and HVS in common marmosets suggets that this species may be a different type of model for human cancer research than the cottontop marmoset, which is the most susceptible animal host for EBV and HVS oncogenesis.

Animals↗
PubMed1978

Clinical evaluation of EBV serology in American patients with nasopharyngeal carcinoma.

There is now extensive immunological, biological and biochemical evidence to support a possible etiological relationship between EBV and NPC in patients from different geographical locations. Besides providing information on the question of etiology, the results from immunological investigations suggest that antibodies to some of the EBV-associated antigens might also be of clinical importance in the diagnosis and prognosis of NPC. To determine the possible clinical application of EBV serology to American NPC, sera from patients seen at the Mayo Clinic and the National Institutes of Health were examined for antibodies to EBV-associated antigens in an effort to identify those parameters which most reliably distinguish NPC from other types of cancer. The results show that high antibody titres to EBV-induced EA and the presence of antibody to EBV antigens in the IgA immunoglobulin fraction were the two most specific discriminating parameters, although neither was infallible. These findings are discussed in relation to future studies that are needed in order to determine the potential clinical value of EBV serology to the diagnosis and prognosis of NPC.

Antibodies, Viral↗
PubMed1977

Enhanced oncogenic behavior of human and mouse cells after cellular hybridization with Burkitt tumor cells.

Studies were made of the expression of the Epstein-Barr virus (EBV) in somatic hybrids of Burkitt tumor cells and human or mouse cells to determine whether EBV genetic information associated with the capacity to transform leukocytes of human and non-human primates could be maintained and expressed in nonlymphoblastoid cells. Data obtained thus far suggest that at least one characteristic associated with cellular transformation (loss of contact inhibition) is expressed only in nonlymphoblastoid cells in which the EBV genome is maintained. In addition, we have demonstrated that human epithelial/Burkitt hybrid cells (D98/HR-1 and D98/Raji) are more oncogenic in nude (athymic) mice than are cells of the human epithelial parental line, D98, or one of the Burkitt lymphoblastoid parent cell lines (Raji); the HR-1 Burkitt parent cell line was as oncogenic as the hybrid cell lines but the time required to induce tumors was much longer. Thus, human epithelial cells show alteration of growth properties in vitro and in vivo after cellular hybridization with Burkitt tumor cells.

Animals↗