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Biomedical subjects

A Payne

Publications and source records attributed to A Payne.

51 records · Page 3Linked to original sources
PubMed1989

Campylobacter pylori in esophagus, antrum, and duodenum. A histological and microbiological study.

Two hundred forty-six patients with a wide range of upper gastrointestinal tract disorders were investigated for the presence of Campylobacter pylori infection in esophagus, gastric antrum, and duodenum. C. pylori was identified in 52% of patients in at least one site, and microbiological and histological techniques were used to exclude the presence of the organism. Esophageal infection was not significant and is probably due to reflux. Antral C. pylori was significantly associated with active gastritis and active duodenitis and is possibly pathogenic.

Adolescent↗
PubMed1988

Milrinone effects in the isolated immature rabbit heart.

Milrinone, a new positive inotropic agent, was evaluated and compared to isoproterenol in an immature isolated isovolumic rabbit heart model. Three age groups were studied: newborns (0-6 days), juveniles (4-6 weeks old) and adults (5-7 months old). Heart rate did not change significantly with milrinone or isoproterenol in adults or juveniles, but increased in newborns from 144 +/- 1 to 162 +/- (SEM) 6 beats/min at peak milrinone effect. Milrinone had a greater effect on the contractility (maximum positive dP/dt) of the mature hearts, with newborns increasing to 134 +/- 6% of baseline, juveniles to 154 +/- 8% and adults to 216 +/- 15%. Results were similar for isoproterenol, although the positive inotropic effect occurred over a wider dosage range for this drug. No additive effects of the two drugs were noted. We conclude, that although milrinone is a positive inotropic drug in all age groups studied, the response of the newborn heart is quantitatively much weaker than that of the adult.

Aging↗
PubMed1987

Characteristics of a novel lentivirus derived from South African sheep with pulmonary adenocarcinoma (jaagsiekte).

A novel lentivirus was isolated from South African sheep with experimentally transmitted lung adenocarcinoma. Similar to visna virus and caprine arthritis encephalitis virus, this new strain induced cytopathic effects on ovine plexus choroid cultures. In contrast to a recent Israeli isolate from sheep with adenocarcinoma, the South African lentivirus could not transform fibroblast cultures. The antigenic relatedness between the new isolate and visna virus was assessed by immunoprecipitation of radiolabeled viral proteins, using monospecific antisera against visna virus proteins. The results indicate that the new virus contains four major structural proteins of sizes similar to those of visna virus (i.e., gp135, p30, p16, and p14) and have some common antigenic determinants (about 90% in the major core antigen p30). However, the nucleotidic sequences of the novel lentivirus were found to be only 16.5 to 27.4% homologous to visna virus and 8.3 to 15% homologous to caprine arthritis encephalitis virus, by means of liquid hybridization under stringent conditions. The genetic divergence indicated by this last result was confirmed by the dissimilar restriction endonuclease cleavage map of the new virus in comparison to those of visna virus and three caprine arthritis encephalitis virus strains. The demonstration of a third type of ovine lentivirus supports the concept of an important genetic variation among the lentiviruses infecting one animal species.

Animals↗
PubMed1987

Global myocardial ischemia in the newborn, juvenile, and adult isolated isovolumic rabbit heart. Age-related differences in systolic function, diastolic stiffness, coronary resistance, myocardial oxygen consumption, and extracellular pH.

Controversy persists over the relative tolerance of the immature myocardium to global ischemia. Thus, we evaluated the physiologic effects of 30, 60, and 180 minutes of global ischemia in an isolated, isovolumic rabbit heart model, at 3 different ages: newborns (less than 1 week of age) (n = 36), juveniles (4 to 6 weeks old) (n = 36), and adults (5 to 7 months old) (n = 36). Following 30 and 60 minutes of ischemia, respectively, adults recovered 87 +/- 4% (mean +/- SEM) and 90 +/- 7% of baseline systolic function, and juveniles recovered 91 +/- 10% and 85 +/- 8%. In contrast, newborns recovered only 27 +/- 6% and 28 +/- 4% of baseline systolic function (p less than 0.05 compared to adults and juveniles). During ischemia, newborn hearts became stiff more rapidly, reaching 361 +/- 46% of baseline stiffness by 60 minutes, whereas adults and juveniles were at 122 +/- 33% and 92 +/- 18% of baseline stiffness (p less than 0.05 newborns compared to adults and juveniles). With reperfusion after 60 minutes of ischemia, the work efficiency of the newborn heart deteriorated to 39 +/- 7% of baseline, compared with 95 +/- 7% and 91 +/- 7% of baseline efficiency in the adult and juvenile hearts (p less than 0.05, newborns compared to adults and juveniles). The ratio of tissue wet-to-dry weights were similar in all age groups after ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1986

Isolation and identification of a South African lentivirus from jaagsiekte lungs.

In the course of attempts to grow the jaagsiekte retrovirus in cell culture, a typical lentivirus was isolated for the first time in South Africa from adenomatous lungs. Morphologically the virus could not be distinguished from other lentiviruses, but serologically it was shown to be more closely related to visna virus than to caprine arthritis-encephalitis virus. However, a preliminary restriction enzyme analysis of the linear proviral DNA of this new lentivirus (SA-DMVV) revealed that it is significantly district from visna virus and CAEV and therefore may represent a third type of lentivirus. Antibodies to the virus were demonstrated in a number of sheep in various parts of the country, but a direct link to a disease condition was not found. Attempts to produce lung lesions by intratracheal injection of the virus have been unsuccessful to date but a transient arthritis was produced by intraarticular inoculation. Viral replication seems to be enhanced in jaagsiekte lungs.

Animals↗
PubMedDate not supplied

A dynamic two-dimensional phantom for ultrasound hyperthermia controller testing.

A new thin layer phantom for testing hyperthermia controllers has been constructed and evaluated using an ultrasound hyperthermia system. The phantom's thermal behaviour agrees with the characteristics of the Pennes' bio-heat transfer equation (BHTE). In particular, the experimental and theoretical results agree in the following ways. First, with respect to the power deposition: for a given power magnitude and scan radius, the shape of the temperature distribution across the phantom corresponds to the shape predicted by the BHTE and the experimental and theoretical temperature values agree closely; when the power magnitude is varied at a fixed scan radius, the average temperature of the phantom varies linearly with the applied power, and as the scan radius is varied at a fixed power magnitude, the average temperature increases with decreasing scan radius size. Secondly, with respect to perfusion: increasing or decreasing the flow rate over the phantom simulates an increase or decrease in the BHTE perfusion term, and the estimated perfusion values are dependent on flow rate only, and are not functions of power or geometry. The combination of these experimental and theoretical results validate the phantom's potential for testing feedback control systems, particularly for future use in the development and verification of model-based controllers. The use of this phantom should improve and accelerate the testing and evaluation of feedback control systems, and reduce the need for animal and human testing.

Animals↗
PubMedDate not supplied

Sleep automatism: clinical study in forensic nursing.

The authors describe sleep automatism as it pertains to forensic nursing. A plea of sane automatism may result in an acquittal and, as a defense, creates a very interesting medical legal circumstance. A case study is presented to illustrate the necessity for nursing to know how to assess for this dissociative state, to understand the legal implications, and to identify nursing issues relevant to sleep automatism defenses. The clinical and personality characteristics on which evaluations should be based are also outlined.

Adult↗
PubMedDate not supplied

Intraoral air pressure discrimination under conditions of partial and complete resistance.

This study assessed a sample of normal-speaking individuals' ability to discriminate differences in their self-generated intraoral air pressures. Two conditions were employed: (1) open tube in which subjects had to sustain an expiratory breath stream to maintain the target pressure, and (2) closed tube in which there was complete resistance to the subjects' breath stream. Analysis of variance revealed no significant difference (p > 0.05) in subjects' ability to discriminate differences in their self-generated intraoral air pressure as a function of open or closed tube conditions. However, subjects' discrimination scores significantly increased (p < 0.05) as the standard pressure was increased.

Adult↗