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Biomedical subjects

A Wallace

Publications and source records attributed to A Wallace.

At least 109 records · Page 6Linked to original sources
PubMed1976

Duration of hospitalization in "uncomplicated completed acute myocardial infarction". An Ad Hoc Committee review.

The clinical and laboratory findings diagnostic of acute myocardial infarction include at least two of the following: (1) a history of pain consistent with myocardial ischemia, (2) electorcardiographic findings consistent with infarction, and (3) a rise in the serum level of specific cardiac enzymes. By the 4th or 5th day of illness, specific criteria can be applied to assign certain patients to a subset with "uncomplicated completed acute myocardial infarction." These criteria include the absence of evidence of (1) continuing cardiac ischemia, (2) left ventricular failure, (3) shock, (4) important cardiac arrhythmias, (5) conduction disturbances, and (6) other serious illnesses in patients with an established acute myocardial infarction. In terms of prognosis and management, patients in this subset should be regarded as substantively different from patients in other subsets. They should respond favorably to short periods of immobilization and hospitalization than those generally used. They may remain at bed rest (modified in regard to sitting and the use of a commode) for 4 days. Subsequently, mobilization with a program of progressive activity over the ensuing 5 to 10 days should reduce the duration of hospitalization to less than the current average of 17.5 to 20.8 days for patients with acute myocardial infarction. Nine to 14 days should suffice in most instances. Current and future trials may indicate that still earlier mobilization and shorter hospitalization periods can be applied to certain patient groups, but the evidence on this point is incomplete. For the individual patient, many factors will determine the optimal duration of bed rest and hospital stay. The patient's physician must consider the therapeutic benefits that may attend earlier mobilization and shorter hospitalization while weighing potential disadvantages. When the responsible physician does not regularly care for the patient, consultation with an experienced cardiologist is desirable. Patients whose condition is classified as "uncomplicated" may manifest deterioration during their illness and require assignment to a subset with a different prognosis and requiring different forms of treatment. For patients with uncomplicated acute myocardial infarction, as well as those in other subsets, absolute rules for therapy are unwise and application of broader principles by the alert physician is more likely to be beneficial.

Arrhythmias, Cardiac↗
PubMed1976

The effect of desert conditions on the reactivity of Libyan schoolchildren to a range of new tuberculins.

This study was carried out to investigate the effect of desert conditions on the pattern of delayed hypersensitivity to mycobacteria in school children aged 6-10 and 11-18 years. A new range of tuberculins prepared from ultrasonic lysates of living mycobacteria belonging to 12 different species was employed. Three centres were chosen for study, a sea port and two desert towns differing greatly from each other. The results obtained were compared with those of a previous study using the same reagents in Kenya. As expected both the range of mycobacterial species to which the children reacted, the rate of acquisition of specific hypersensitivity with age and the total percentage of children reacting to individual reagents differed from centre to centre. The harsh desert conditions of Ajdabia produced the least, and the proximity of the people's dwellings to those of their farm animals in Kufra produced the most positive reactors to essentially environmental species. The greatest number of reactions to our Tuberculin were found in Benghazi where the cosmopolitan urban conditions probably lead to a high contact with open cases of tuberculosis. As assessed by skin test reactivity, immunization with BCG in Libya was much less effective than in Kenya. The interpretation of the differences between the results from the different test centres and between those for Libya and Kenya are discussed.

Adolescent↗
PubMed1976

The Edinburgh spleen: source of a validated Kveim-Siltzbach test material.

Although it is true that some Kveim-Siltzbach test suspension may for reasons unknown behave in a totally nonspecific way and so be useless in the confirmation of active sarcoidosis, the experience with the Edinburgh spleen has shown that it is also true that a preparation can be made which acts specifically in the sarcoid context and fulfils all the Siltzbach criteria. The active principle probably resides in the membrane components of sarcoid tissue cells.

Antigens↗
PubMed1972

Transport of sodium into the xylem exudate of tobacco.

When tobacco (Nicotiana tabacum L. var. Virginia Gold) plants were pretreated with Na ((22)Na) several days before detopping, from 2.3 to 4.9% of Na previously accumulated in roots appeared in the xylem exudate in 7 days after detopping. Na from the external medium, however, was readily transported to the exudate. Moreover, the amount of the pretreatment Na that was transported to the exudate was not influenced by the presence of Na in the external medium. When Na was present in the external medium after detopping, about 4% (with an NaNO(3) post treatment) to 10% (with an NaCl post treatment) of the Na transported to the xylem in the 7 days following detopping originated in the vacuoles. Nitrate salts of K or Na in the external medium after detopping resulted in transport of large quantities of the respective cation to the exudate, but not in increased transport of the pretreatment Na. A much larger percentage of the K that was accumulated after detopping than of the Na similarly accumulated was transferred to the xylem exudate.

Journal Article↗
PubMed1970

Effect of cycloheximide, gamma irradiation, and phosphorus deficiency on root pressure exudation in tobacco.

Cycloheximide drastically reduced the rate of root pressure exudation in detopped tobacco (Nicotiana tabacum L.), and the effect was more pronounced for nitrate salts in the external solution than for some other salts or when the roots were in water. Diurnal periodicity was greatly decreased, and its phase was changed. Effects began within an hour. Cation uptake was reduced by relatively low levels of cycloheximide. The effects of cycloheximide seemed to be reversible. Mild phosphorus deficiency resulted in decreased exudation rates from detopped tobacco and in no response to nitrate. Periodicity of exudation was not greatly affected by phosphorus deficiency, however. Gamma ray irradiation with a (60)Co source at levels (up to 40-50 kiloroentgens) which are considered disruptive of moderately large molecules had relatively little effect on the exudation rate. Higher levels of irradiation, which disrupt most protein molecules, decreased exudation and obscured periodicity. The results indicate either that new protein (or peptide) synthesis is needed for the rapid nitrate transport or that the deficiency and inhibitor disrupt cellular membranes. Phosphorus deficiency increased the sensitivity of the plants to inhibition by irradiation of the exudation process.

Journal Article↗