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Biomedical subjects

M Johnson

Publications and source records attributed to M Johnson.

At least 577 records · Page 32Linked to original sources
PubMed1990

Nurses respond to Hurricane Hugo victims' disaster stress.

Hugo, a class IV hurricane, hit South Carolina September 22, 1989, and left behind a wake of terror and destruction. Sixty-one nursing students and five faculty were involved in disaster relief with families devastated by the hurricane. A review of the literature led these authors to propose a formulation of the concept of disaster stress, a synthesis of theories that explains response to disaster as a crisis response, a stress response, or as posttraumatic stress. With the concept of disaster stress serving as a theoretical foundation, the nurses observed, assessed, and intervened with one population of hurricane Hugo victims, noting their immediate psychosocial reactions and coping mechanisms. Victims' reactions to disaster stress included confusion, irritability, lethargy, withdrawal, and crying. The most frequently observed coping strategy of these hurricane Hugo victims was talking about their experiences; other coping tactics involved humor, religion, and altruism.

Aged↗
PubMed1990

In vivo photosensitizer-enhanced laser angioplasty in atherosclerotic Yucatan miniswine.

Photosensitization of atherosclerotic (Ath) plaque with exogenous chromophores may confine laser irradiation (LI) injury to Ath plaque and allow safer and more efficacious laser angioplasty. Dihematoporphyrin ether (DHE) accumulates preferentially in plaque, and previous in vitro LI studies have shown confinement of LI injury to plaque. To further evaluate DHE enhanced laser angioplasty, 5 Ath Yucatan miniswine with 8 iliofemoral stenoses (Sten) were treated with 2.5 mg/kg of DHE IV. Twenty-four hours later, 632 nm continuous wave LI was delivered to Sten using 200mu core optical fiber with a 582mu x 1cm diffusing tip. Angiograms were performed before, immediately after, and two weeks following LI. 6 of 8 vessels showed improvement. Control mean Sten was 71%, immediate post LI was 55% and 2 weeks post LI was 19% Sten. In 4 of 6 responding vessels, there was 0% Sten at 2 weeks post LI and the previously stenotic segments appeared normal. 2 of 6 responders showed only modest improvement, from control mean Sten of 83% to 55% Sten at 2 weeks. 2 of 8 vessels showed no improvement. There were no perforations or dissections. The excellent results in some vessels demonstrate the potential of photosensitizer enhanced LI as very effective primary therapy of Ath. The time course of improvement indicates that both immediate thermal and delayed photochemical (photodynamic therapy) effects are operative. Further studies are required to identify reasons for failure in some vessels.

Angioplasty, Laser↗
PubMed1990

Willingness of health-professions students to treat patients with AIDS.

This 1988-89 survey of 319 students in the medical, dental, nursing, and allied health-care professions revealed that over one-third had some reservations about treating acquired immunodeficiency syndrome (AIDS) patients. Most were unwilling to perform mouth-to-mouth resuscitation on patients with AIDS, and most also believed that health-care workers had the right to refuse care to AIDS patients. Unwillingness to treat AIDS patients was strongly associated with homophobic attitudes and concerns that patients with AIDS posed a risk to health professionals. AIDS education for health professionals should emphasize methods for the prevention of HIV infection among health workers, and include teaching strategies designed to deal with the irrational feelings that AIDS often engenders.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Does continuous positive airway pressure compensate for loss of glottic function during tracheal intubation?

Adult patients with acute lung injury (ALI) exhibit increased PaO2 when receiving continuous positive airway pressure (CPAP). Some have increased PaO2 after extubation. To determine the role a competent glottis played in improving gas exchange, we anesthetized seven rabbits and inserted central venous and carotid artery catheters. After recovery from anesthesia, ALI was induced with oleic acid (0.08 ml/kg). Twenty-four hours later, the animals were sedated and placed in a sling. The pHa and blood gas tensions were measured. The animals were placed supine and were given inhalation anesthesia to facilitate tracheal intubation. A polyethylene catheter was placed slightly distal to the tracheal tube outlet to measure tracheal pressure (PT). Intubated rabbits were repositioned in the sling and were given either zero end-expiratory pressure (ZEEP) or 5 cm H2O CPAP, alternately. After the animals had breathed room air for 60 min, pHa and blood gas tensions were again measured, and PT was recorded. Animals were extubated, but the PT catheter was left in place. Data were collected again 60 min later, the catheter was removed, and the animals were returned to their cages. Forty-eight hours after onset of ALI, the protocol was repeated.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Natural sociology and moral questions in nursing: can there be a relationship?

This paper argues that the current sources of material for the debate of moral questions in health care in general and nursing in particular, are inadequate. The current bases of nursing's knowledge and values are explored, and the conclusion drawn that reliance upon theory developed by other disciplines has led to theories which are wholly inappropriate to explain either how nursing is practised or even how it ought to be. A case is made that naturalistic sociological methods such as participant observation have the greatest possibilities to describe and explain moral conduct in nursing. Further, these methods can produce a view of reality more consistent with the experiences and feelings of the patients or clients and other health workers. It would seem that data and theory generated using this perspective could better inform the debates of moral philosophers than the currently dominant sources of their case material, the views of the medical and legal professions.

Casuistry↗
PubMed1990

Effects of acute alcohol intake on tolerance to hypotension.

The specific aim of this research was to test the hypothesis that intoxication with alcohol results in poor tolerance to hemorrhage. This was evaluated on the basis of blood pressure, cardiac output respiratory rate, blood flow to organs, and survival for 4 hr after hemorrhage. Four groups of six swine per group were used (control, intoxicated, hemorrhage, and intoxicated-hemorrhage). The results revealed that blood alcohol concentrations near 0.1% greatly reduced tolerance to hemorrhage. Intoxicated animals subjected to hemorrhage were unable to maintain an adequate cardiac output, blood pressure, or respiratory rate to sustain life. Pigs tolerated higher blood alcohol concentrations, up to 0.35%, when not exposed to hemorrhage. Also, unintoxicated pigs were able to compensate for severe hemorrhage. Only one of the six pigs in the intoxicated-hemorrhage group survived for 4 hr after hemorrhage. In conclusion the body's ability to compensate and recover from hemorrhage was greatly reduced during intoxication. It is logical to assume that the ability to overcome numerous other stressors may also be reduced during intoxication.

Alcoholic Intoxication↗
PubMed1990

Immunological features of lung lavage cells from patients with primary biliary cirrhosis may reflect those seen in pulmonary sarcoidosis.

To investigate the basis of subclinical alveolitis in patients with primary biliary cirrhosis, 10 primary biliary cirrhosis patients were studied by bronchoalveolar lavage. Both bronchoalveolar lavage lymphoid and non-lymphoid cell populations were analysed using immunocytological methods to determine their proportions and phenotypic features in an attempt to gain information as to possible immune mechanisms active in the lung of these patients. Six of the 10 patients in our study showed evidence of an alveolitis (raised lymphocyte count: 27.6 (4.3)% of total count) on lavage. The results were compared with control groups of normal volunteers and patients with active pulmonary sarcoidosis. The six primary biliary cirrhosis patients with lymphocytosis had a raised CD4/CD8 T-cell ratio (4.13:1), similar to the sarcoid patients (5.60:1). A proportion of these T-lymphocytes expressed markers of activation (HLA-DR+ 7.5 (2.1)%); CD25 + 2.3 (0.9)%; CD7 + 5.8 (1.5)%. This increased T-cell activation was also seen in the sarcoid groups (HLA-DR+ 10.0 (1.9)%; CD25 + 3.0 (1.1)%; CD7 + 5.0 (0.2)%). This was not seen in the primary biliary cirrhosis patients without lymphocytosis and the normal volunteers. Within the non-lymphoid cell population, an increase in dendritic (RFD1+) cells was seen in primary biliary cirrhosis patients with lymphocytosis (31.2 (1.9)%) and sarcoid patients (46.3 (5.1)%) in contrast with the normal and primary biliary cirrhosis group without lymphocytosis. The primary biliary cirrhosis patients without lymphocytes had a relatively greater proportion of mature phagocytes (RFD7+). We postulate that these observations suggest the emergence in the lung of a granuloma producing mechanism similar to that occurring in the liver. By comparison, the alveolitis found in primary biliary cirrhosis is consistent with that observed in interstitial granulomatous lung disorders such as sarcoidosis.

Bronchoalveolar Lavage Fluid↗
PubMed1990

New initiatives in a district AIDS counselling unit, 1988-89.

This paper describes the workload of the AIDS Counselling Unit in Hampstead District Health Authority during its second year of service. Between April 1988 and March 1989, the average number of patients seen each month by the Unit doubled. It is anticipated that the caseload in the district will continue to increase, both among those with human immunodeficiency virus (HIV) infection and those without. New initiatives were developed within the district during the year. These included a new inpatient facility for patients with the acquired immunodeficiency syndrome (AIDS), the appointment of a designated HIV/AIDS consultant, and counselling services for people attending the antenatal clinic as well as those entering drug trials. Appropriate counselling services will need to be established in other health districts to meet local demand.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Effects of cocaine on extrapyramidal and limbic dynorphin systems.

The principal central nervous system effects of cocaine are a consequence of its ability to inhibit monoaminergic uptake systems. This agent influences dopamine-related behavior in a manner similar to other sympathomimetics, such as methamphetamine; however, the effect of these two agents on neurochemical dopaminergic parameters are distinct. Several peptidergic neurotransmitter systems, such as the dynorphin pathways, have been shown to be distal to and regulated by the postsynaptic activity of dopaminergic pathways; therefore, we evaluated the response of extrapyramidal and limbic dynorphin A1-17 (Dyn) systems to cocaine by measuring Dyn content in associated structures. Extrapyramidal and limbic dynorphin-like immunoreactivity (DLI) content markedly increased after cocaine treatment. This change appeared to be due primarily to the ability of cocaine to block dopamine re-uptake; consequently, the increase in DLI levels was either totally or partially blocked by coadministration of selective D1 (SCH 23390) and D2 (sulpiride) receptor blockers and multiple doses of the selective dopamine uptake blockers, amfonelic acid and GBR 12909, caused cocaine-like enhancement of extrapyramidal DLI content. Serotonin did not appear to play a major role in mediating the cocaine effects on Dyn systems as multiple doses of the selective serotonin uptake blocker, fluoxetine, did not alter extrapyramidal DLI levels, and depletion of serotonin by pretreatment with parachloroamphetamine did not significantly alter the increases in extrapyramidal Dyn content caused by cocaine administration. Because the behavioral effects of cocaine and methamphetamine are similar, the neurochemical response of Dyn systems to both of these agents is compared and discussed.

Animals↗
PubMed1990

Neurochemical basis of neurotoxicity.

The neurotoxic properties of 6-hydroxydopamine and 5,7-dihydroxytryptamine are reviewed. The neurochemical responses of the dopaminergic and serotonergic systems after methamphetamine (METH) are reported. METH decreased activities of tyrosine hydroxylase and tryptophan hydroxylase; concentrations of dopamine (DA) and 5-hydroxytryptamine (5HT) and their respective metabolites were decreased in parallel with the decline in activity of the enzymes. When a variety of pharmacologic or surgical procedures were used to decrease DA content prior to administration of METH, the effects of METH were attenuated. From these data it is inferred that DA is essential for the METH-induced response. 3,4-Methylenedioxymethamphetamine (MDMA) produced similar effects which were also DA-dependent. Evidence for a role of glutamate and oxidative stress in the neurotoxicity of the amphetamines is presented.

3,4-Methylenedioxyamphetamine↗
PubMed1990

Effect of early and delayed difluoromethylornithine pretreatment upon cyclophosphamide chemotherapy.

The Dunning R3327 MAT-LyLu prostatic adenocarcinoma was utilized to study the effectiveness of an early versus delayed difluoromethylornithine (DFMO)-induced polyamine-depleted environment on cyclophosphamide (CTX) chemotherapy. DFMO (2%) was administered either at the time of tumor inoculation (early) or 36 h after tumor implantation (delayed). CTX (50 mg/kg) was administered to both DFMO groups in two doses; the first 36 h after initiation of DFMO therapy, and the second 1 week later. Each protocol (early and delayed) for combined DFMO/CTX chemotherapy significantly reduced tumor sizes with the earlier DFMO protocol appearing slightly more effective (p less than 0.001 and 0.02, respectively). DFMO administered alone was not significantly effective with either protocol.

Adenocarcinoma↗
PubMed1990

Clinical evaluation of an automated chemical inhibition assay for lactate dehydrogenase isoenzyme 1.

We evaluated an automated assay for lactate dehydrogenase (LD; EC 1.1.1.27) isoenzymes, supplied by Boehringer Mannheim Diagnostics (BMD) and based on selective chemical inhibition of non-LD-1 isoenzymes by guanidine thiocyanate. Results were compared with the Roche Isomune LD-1 method. The Hitachi 717 analyzer was used to measure enzyme activity for both procedures in 229 serum samples. One hundred specimens were also analyzed by the Helena rapid electrophoresis (REP) method. We determined the limit of linearity of the BMD method to be about 1200 U of LD-1 per liter. The analytical correlation of BMD (y) with Isomune (x) yielded y = 1.0x + 0.5 U/L, r = 0.997, Sy/x = 16.9 (range 20-1397 U/L). The regression equation for BMD vs REP was y = 1.1x + 7.2% (r = 0.800, Sy/x = 7.4, range 14-83%). Average values for within-run precision for low (38 U/L), medium (180 U/L), and high (865 U/L) controls were 4.1%, 1.0%, and 0.5%, respectively (16 trials of six each). The average values for run-to-run precision were 4.1%, 1.7%, and 1.1%, respectively, for these controls (n = 16). We used receiver-operating characteristic curves to determine optimum decision limits. Using an LD-1 cutoff of 40% of total LD, we obtained a clinical sensitivity of 97-100% and a specificity of 95% when blood was collected during the optimum interval, 24-48 h after the onset of chest pain. We conclude that the BMD LD-1 assay is equivalent to the immunochemical and electrophoretic assays for measuring the LD-1 isoenzyme.

Autoanalysis↗
PubMed1990

Adjunct executive appointment for faculty. An innovation in nursing collaboration.

The need for collaboration has never been greater. The healthcare delivery system faces unprecedented challenges arising from prospective payment, competition in the marketplace, higher patient acuity levels, and a shortage of professional nursing staff. The authors discuss a service-education collaboration model based on adjunct executive appointments of faculty members to healthcare organizations. The authors describe the model, a conceptual framework to guide its development, case studies of its implementation, and a summary of the benefits and risks associated with the initial implementation of the model.

Hospitals, Community↗
PubMed1989

The influence of the estrous cycle on the activity of striatal neurons recorded from freely moving rats.

Recordings from striatal neurons in conscious rats at various stages of the estrous cycle revealed differences in the activity of the neurons. Average firing rate was higher in diestrus than in animals in estrus or proestrus. The increase did not seem to depend on the motor activity of the animals nor was it present in ovariectomized rats. Since application of estrogen to ovariectomized rats did not change the firing rate of the neurons, we conclude that differences during the cycle in conscious rats are not mediated by an action of estrogen unlike those seen in anesthetized rats. Differing electrode sampling bias in the two situations, or an action of anesthetic in revealing the estrogen effect may explain the differences.

Action Potentials↗