An estimate of the minimal frequency of cytolytic T lymphocyte effector cells generated in allogeneic reactions.

A 'micro' modification of the standard 51Cr release assay was developed. With this assay, significant cytolysis was obtained employing 100--200 51Cr-labeled target cells and fewer than 100 lymphocytes obtained from mixed leukocyte cultures. A minimal estimate as to the actual frequency of effector cells was determined for both primary (1 cell in 30) and secondary (1 cells in 8) cytolytic T lymphocyte populations.     

Axonal trajectory of single group Ia and Ib fibers in the cat spinal cord

Intracellular staining with HRP of physiologically identified group Ia and Ib afferent fibers in the adult cat lumbosacral cord revealed that group Ia and Ib fibers take a similar course in the dorsal funiculus, but the collaterals emerging from them show a different topographical distribution and a different mode of branching in the gray matter. Ia collaterals terminate in laminae VI, VII, IX, and sometimes VIII, whereas Ib collaterals terminate only in lamina VI, or both VI and IX. In lamina IX, two large motor-type neurons received terminations of both Ia and Ib fibers at the same time.     

Quantitative assays of pharmacologic aerosols used in studying asthma

To more nearly accurately quantitate the dose of pharmacologic agents delivered to human and animal airways via aerosols, we have developed a monodisperse aerosol containing either methacholine or histamine that permits a light scattering device (tyndallometry) to measure accurately the quantity of inspired and expired particles. These aerosols (described in previous studies) are simultaneously tagged with a radioactive label (technetium 99m) to permit the use of external gamma camera imaging. Present work focuses on the development of assay techniques to measure the quantity of methacholine delivered in these aerosols. The lack of specific radioimmune or radioenzyme assays coupled with the cross-reaction of organic contaminants with conventional chemical reagents for measuring methacholine required the development of separative techniques to isolate the methacholine from the organic aerosol contaminants. With aqueous extraction and column separation we have been able to completely isolate the methacholine from these contaminants. This allows the application of standard spectrophotometric assays for methacholine to quantitate the methacholine in the resulting solution. These separative techniques will permit the use of these aerosols in quantitative studies of airway reactivity.     

Characteristic features of actinomycin D-induced paw inflammation of the rat.

Features of paw edema induced by subplantar injection of actinomycin D (act D) were investigated in rats. The paw edema was produced as early as the 1st day and reached a maximal level on the 3rd or the 4th day. Thereafter, it began to subside progressively and was considerably reduced by the 16th day following act D (20 μgm) injection. A direct dose response relationship between the amount of act D injected and the intensity of the paw edema was obtained. No difference in β-glucuronidase and acid phosphatase activity was found between saline and act D-injected paws on the 2nd day. This was followed by an increase in the activity of both enzymes on the 4th, 8th, and 16th days after injection. The histamine content of the saline and act D-injected paws remained unchanged during the early phase of inflammation. A marked increase in the histamine content was noted during the late phase in the drug-injected paw. The effects of act D treatment on capillary permeability to Evans blue dye (EBD) and the edema formation of the paw revealed that a maximal increase in vascular permeability to EBD occurred on the 1st day and was maintained until the 8th day. In contrast to permeability, the paw edema on the 1st day was minimal and increased progressively until the 3rd or 4th day. Thereafter, both the permeability and the paw edema began to diminish and were considerably reduced on the 16th day. Aspirin and hydrocortisone treatment were ineffective in suppressing the act D-induced paw inflammation. Indomethacin produced a somewhat dose-related anti-inflammatory effect against the inflammation caused by this drug.     

Histologic,ultrastructural, and enzymatic measurements of infarct size following coronary artery stenosis and occlusion

Coronary artery narrowing (CAN), which reduced resting coronary blood flow (BF) by 50%, was induced in 10 conscious dogs and was maintained for 4 hours. Five additional dogs (group 1) with complete coronary artery occlusion were compared to the dogs with CAN. serum isoenzymes of creatine phosphokinase (CK) and latate dehydrogenase (LD) were monitored hourly in all groups. After 36 hours, samples were obtained for regional myocardial BF, quantitative histology, and quantitative ultrastructural (EM) morphology. Six dogs with CAN had small infarcts (MI) of less than 1 gm and persistent myocardial cell injury (group 2). The other four dogs with CAN had only persistent myocardial cell injury by ultrastructural criteria (group 3). Peak serum CK activities in groups 2 and 3 were similar, as were MI sizes calculated from serum CK and myocardial depletion. MB CK was of diagnostic value in group 1 but not in groups 2 and 3. The ratio of $\text{LD}\text{1}\text{LD 2}$ had diagnostic value in all three groups. MI size by enzyme estimates was consistently higher than planimetered MI size at autopsy in both groups 1 and 2. All three groups had significant amounts of ultrastructural damage outside of histologically demonstrated MI. These findings suggest that (1) gross and histologic MI size determination of 36 hours after ischemia underestimate extent of damage, and (2) ultrastructural cell changes cause significant release of CK and LD in coronary disease (CAD).     

Academic nursing leadership in a rural setting: Different game,same standards

The call for transformation of nursing education and practice continues to be a national priority. The American Association of Colleges of Nursing recommends enhanced partnerships between academic nursing and academic health centers to advance nursing and healthcare. For academic leaders in rural settings, the context of health and healthcare means that these partnerships are vastly different from academic health centers. The purpose of this article is to describe the context of nursing education and practice in regions that are predominantly rural. The challenges and opportunities for rural academic leaders as they respond to calls for transforming the education of the future nursing workforce are described from the perspective of resources, recruitment and retention of faculty, clinical education and faculty practice, scholarship, and fundraising. Meeting rural health workforce needs is a national imperative and a priority of academic nursing leaders in rural settings.     

A note on the "Brody-effect"

The effect of a perfectly conducting sphere simulating the intracavitary blood mass on a dipole source located at the interface with the outer tissue (myocardium) is studied, utilizing image theory. The resulting enhancement factor is found to be a function of the field point location and is not a constant, as previously reported by Brody and by Rush and Nelson.     

Treatment of a case of lanatoside C intoxication with digoxin-specific F(ab')2 antibody fragments.

In animal experiments arrhythmias induced by cardiac glycosides which prove fatal if untreated can be terminated by administration of glycoside-specific antibodies. Immunotherapy with digoxin-specific antibody fragments had hitherto only been employed on one occasion, namely in a person who had taken a massive overdose of digoxin with suicidal intent and who had failed to respond to symptomatic treatment. The present paper describes the use of F(ab')2 fragments of digoxin-specific antibodies in a female patient with lanatoside C intoxication to treat the associated life-threatening cardiac arrhythmia. The arrhythmia was rapidly terminated and normal sinus rhythm was restored. Treatment with the heterologous antibodies did not cause any side-effects.     

Decreased contractility and compliance of the left ventricle as complications of thermal trauma

To test the hypothesis that systemic complications of dermal burns encompass dysfunction of myocardial contractile mechanisms, we studied contraction-relaxation properties of isovolumic left ventricular (LV) preparations isolated from guinea pigs 24 hours after full-thickness burn to approximately 47% total body surface area. Compared to control hearts, hearts from burned subjects consistently generated significantly lower values for LV systolic pressure (94 +/- 2 vs 66 +/- 2 mm Hg; p less than 0.001) and maximal rates of LV pressure rise (+ dP/dtmax; 1296 +/-71 vs 1091 +/- 46 mm Hg X sec-1; p less than 0.05) and fall (-dP/dtmax; 1214 +/- 45 vs 856 +/- 34 mm Hg X sec-1; p less than 0.001). The LV contractile deficit of burn hearts was not correlated with changes in tissue water content, and it was not surmountable by excess glucose, insulin, increased coronary flow, or maximal preload elevation. In addition, end-diastolic pressure-volume relationships in burn hearts were shifted upward and to the left of controls in the direction of decreased compliance (p less than 0.05 to p less than 0.01). Thus, LV sequelae of thermal trauma manifest in isolated hearts as decreased contractility, slowed isovolumic relaxation, and decreased diastolic compliance; in the intact animal this combination would reduce ejection and impede filling of the ventricle, with diastolic pressures reflecting changes in compliance as well as in contractile function.