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N Edwards

Publications and source records attributed to N Edwards.

At least 73 records · Page 4Linked to original sources
PubMed1996

Hypercapnic blood pressure response is greater during the luteal phase of the menstrual cycle.

We investigated the cardiovascular responses to acute hypercapnia during the menstrual cycle. Eleven female subjects with regular menstrual cycles performed hypercapnic rebreathing tests during the follicular and luteal phases of their menstrual cycles. Ventilatory and cardiovascular variables were recorded breath by breath. Serum progesterone and estradiol were measured on each occasion. Serum progesterone was higher during the luteal [50.4 +/- 9.6 (SE) nmol/l] than during the follicular phase (2.1 +/- 0.7 nmol/l; P < 0.001), but serum estradiol did not differ (follicular phase, 324 +/- 101 pmol/l; luteal phase, 162 +/- 71 pmol/l; P = 0.61). The systolic blood pressure responses during hypercapnia were 2.0 +/- 0.3 and 4.0 +/- 0.5 mmHg/Torr (1 Torr = 1 mmHg rise in end-tidal PCO2) during the follicular and luteal phases, respectively, of the menstrual cycle (P < 0.01). The diastolic blood pressure responses were 1.1 +/- 0.2 and 2.1 +/- 0.3 mmHg/Torr during the follicular and luteal phases, respectively (P < 0.002). Heart rate responses did not differ during the luteal (1.7 +/- 0.3 beats.min-1.Torr-1) and follicular phases (1.4 +/- 0.3 beats.min-1.Torr-1; P = 0.59). These data demonstrate a greater pressor response during the luteal phase of the menstrual cycle that may be related to higher serum progesterone concentrations.

Adult↗
PubMed1995

Age-related development of human anti-pig xenoantibody.

Human cytotoxic natural xenoantibodies are believed to be of the immunoglobulin M class in nature. However, a thorough understanding of the development of these natural antixenodonor xenoantibodies remains incomplete. In this study, serum samples were obtained from newborn, infant, and adult human beings. An enzyme-linked immunosorbent assay was used to determine the binding of human natural immunoglobulin M xenoantibodies to pig aortic endothelial cells and pig lymphocytes. A complement-mediated cytotoxicity assay was used to measure the cytotoxicity of newborn, infant, and adult serum to cultured pig aortic endothelial cells and pig lymphocytes. Adult human serum contained both natural immunoglobulin M and immunoglobulin G xenoantibodies to pig endothelial cells and lymphocytes, whereas newborn infant serum contained only immunoglobulin G xenoantibodies. Only adult human serum was cytotoxic to pig endothelial cells and lymphocytes. Human immunoglobulin M xenoantibodies became detectable by age 1 month. By age 2 months these natural anti-pig xenoantibodies reached serum levels equivalent to those in the human adult and resulted in similar cytotoxicity to that of adult human serum. These findings indicate that (1) natural anti-pig immunoglobulin M xenoantibodies are absent from newborn infant human serum, (2) newborn human serum is not cytotoxic to pig endothelial cells and lymphocytes despite the presence of immunoglobulin G xenoantibodies that bind to pig endothelial cells and lymphocytes, and (3) natural anti-pig immunoglobulin M xenoantibodies begin to develop as early as age 1 month and by age 2 months attain a circulating level comparable to that found in the adult.

Adult↗
PubMed1994

The use of a visual aid to check anaesthetic machines. Is performance improved?

We asked 20 anaesthetists and seven operating department assistants to check three anaesthetic machines 'doctored' to contain errors of varying seriousness, and recorded their performances. Two weeks later we asked the same group to repeat the test. On the second occasion they followed a visual aid and filled in a questionnaire about the test. Participants showed a significant improvement in the rate of fault detection when using the aid (p < 0.05). The visual aid was most useful at increasing the detection rate of machine leaks. Of the participants, 60% considered that the visual aid was helpful and 74% thought that such an aid should be available in our theatre complex. Sixty-six percent of those questioned felt that a formal check list would be of use.

Anesthesiology↗
PubMed1994

Difficult intubation following thoracic trauma.

A previously fit 20-year-old man presented with a large haemothorax following a stab wound to the left chest. Pre-operative airway assessment indicated that tracheal intubation would be routine. On induction of anaesthesia, visualisation of the larynx proved impossible because of soft tissue swelling. Successful intubation was eventually achieved with the aid of a gum elastic bougie. At operation, the patient's common carotid artery was found to have been perforated close to its origin on the aorta. The patient made an uneventful recovery.

Adult↗
PubMed1994

In vivo myocardial kinetics of air-filled albumin microbubbles during myocardial contrast echocardiography. Comparison with radiolabeled red blood cells.

Myocardial contrast echocardiography (MCE) is a new technique for assessing myocardial perfusion that uses intracoronary injections of microbubbles of air. Because these microbubbles have a mean diameter of 4.3 +/- 0.3 microns and an intravascular rheology similar to that of red blood cells (RBCs), we hypothesized that their mean myocardial transit rates recorded on echocardiography would provide an estimation of regional myocardial blood flow in the in vivo beating heart. Accordingly, blood flow to the left anterior descending coronary artery (LAD) of 12 open-chest anesthetized dogs (group I) was adjusted to 4 to 6 flows (total of 60 flows), and microbubbles and radiolabeled RBCs were injected into the LAD in a random order at each stage. The mean myocardial RBC transit rates were measured by fitting a gamma-variate function to time-activity plots generated by placing a miniature CsI2 probe over the anterior surface of the heart, and the mean myocardial microbubble transit rates were measured from time-intensity plots derived from off-line analysis of MCE images obtained during the injection of microbubbles. An excellent correlation was noted between flow (measured with an extracorporeal electromagnetic flow probe) and mean myocardial RBC transit rate (y = 2.83 x 10(-3)x + 0.01, r = .96, SEE = 0.02, P < .001). A close correlation was also noted between mean RBC and microbubble myocardial transit rates (y = 1.01x + 0.01, r = .89, SEE = 0.02, P < .001). Despite its theoretical advantages, a lagged normal density function did not provide a better fit to the MCE data than the gamma-variate function.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗
PubMed1994

Refinement of the Medicare diagnosis-related groups to incorporate a measure of severity.

This article presents a system under consideration by the Health Care Financing Administration (HCFA) for incorporating a measure of severity of illness into the Medicare diagnosis-related groups (DRGs). DRG assignment is one of the main factors in determining the payment made for hospital inpatient services furnished to Medicare beneficiaries. Specifically, the formula used to calculate payment for a single Medicare hospital inpatient case takes an average payment rate for a typical case and multiplies it by the relative weight of the DRG to which it is assigned. Thus, it is easy to see that the DRG relative weights have a large impact on the payment a hospital receives. In this article, we describe the Medicare DRG prospective payment system (PPS), evaluate the various classification elements available for assessing severity of illness, describe the analyses used in formulating this proposal, and present the proposed DRG severity system.

Centers for Medicare and Medicaid Services, U.S.↗
PubMed1991

Autoregulation of the immune response in autoimmune disease and cardiac transplantation by photoinactivated autologous lymphocytes.

These studies demonstrate that photochemotherapy can be successfully evaluated in animal models. The therapy mediates specific suppression of immune responses and appears to operate at the level of the effector T cells. Future studies will focus on isolation and characterization of the host response to photochemotherapy. The extention of this form of therapy to conditions mediated by dysfunctional regulation of effector T cells is already in progress in clinical trials of cardiac allograft transplantation and autoimmune disease. The results of these trials will provide more evidence on the role of this form of therapy in autoregulation of the immune response.

Animals↗