Showing papers by "University of Alabama at Birmingham published in 1982"

Contrast sensitivity throughout adulthood

Abstract: Previous studies of spatial contrast sensitivity in adulthood have produced conflicting results. To clarify the situation, we measured contrast sensitivity functions on a large sample of adults (n = 91), ranging in age from 19 to 87. All observers were free from significant ocular pathology and were individually refracted for the test distance. Sensitivity for stationary gratings of low spatial frequency remained the same throughout adulthood. At higher spatial frequencies, sensitivity decreased with age beginning around 40 to 50 years. When a low spatial frequency grating was drifted, young adults' sensitivity improved by a factor of 4-5 over sensitivity to a static grating; this motion enhancement was markedly diminished in adults over 60 years, implying an impairment of temporal processing in the elderly. Reduced retinal illuminance characteristic of the aged eye could account for a large part of older adults' deficit in spatial vision, but appeared to play little role in their deficit in temporal vision.

Left-handed Z-DNA is induced by supercoiling in physiological ionic conditions

Abstract: In physiological ionic conditions (200mM NaCl), the (dC–dG)16 and (dC–dG)13 blocks in plasmid pRW751 are in a left-handed state when the negative superhelical density of the plasmid is greater than 0.072. As the salt concentration decreases or when (dmC–dG) sequences are present, less negative supercoiling is required to induce the right- to left-handed DNA transition. Furthermore, the single strand-specific nuclease, S1, recognizes and cleaves aberrant structural features at the junction between neighbouring right- and left-handed DNA regions.

Coronary vascular reactivity after acute myocardial ischemia.

Abstract: Exogenous thrombin produced a biphasic response (a potent dose-related vasodilatation followed by vasoconstriction) in nonischemic canine coronary arteries. The vasodilatation was not blocked by propranolol, atropine, or indomethacin, but was completely blocked by heparin or denudation of the intimal endothelial cells. A similar loss of vasodilating response to thrombin occurred in ischemic coronary arteries with a concomitant enhancement of vasoconstriction. This study indicates that altered responses to thrombin in coronary arteries with damaged endothelium may play an important role in the pathogenesis of coronary vasospasm.

A comparison of prognostic factors and surgical results in 1,786 patients with localized (stage I) melanoma treated in Alabama, USA, and New South Wales, Australia.

Abstract: Twelve clinical and pathologic parameters were compared in two series of Stage I melanoma patients treated at the University of Alabama in Birmingham, USA (676 patients) and at the University of Sydney in New South Wales, Australia (1,110 patients). Actuarial survival rates were virtually the same at the two institutions over a 25-year follow-up period. The incidence of thin melanomas (less than 0.76 mm) was also similar at both geographic locations (25% vs. 26%). Other similarities of these two patient populations included the following: 1) tumor thickness (Breslow Microstaging). 2) level of invasion (Clark Microstaging), 3) surgical results, 4) sex distribution, and 5) age distribution. The greatest differences between the two patient populations were their 1) anatomic distribution, 2) growth pattern, and 3) incidence of ulceration. The trunk was the most common site of melanoma, and occurred more frequently among Australian patients (37% vs. 28%). A multifactorial analysis (Cox's regression model) was then performed that included a comparison of the two institutions as a variable (Alabama vs. Australia). The dominant prognostic factors (p less than 0.0001) were 1) ulceration, 2) tumor thickness, 3) initial surgical management (wide excision +/- node dissection), 4) anatomic location, 5) pathologic stage (I vs. II), and 6) level of invasion. The benefit of elective lymph node dissection was demonstrated in both series for patients with intermediate thickness melanoma (0.76 to 3.99 mm.) For melanomas ranging from 0.76 to 1.5 mm in thickness, the benefit of node dissection was primarily in male patients. Survival rates for melanoma at the two institutions were not significantly different in the multifactorial analysis, even after adjusting for all other variable. Thus, the biologic behavior of melanoma in these two different parts of the world was virtually the same, with only minor differences that did not significantly influence survival rates. Long-term follow-up exceeding eight to ten years after surgery is critical in the interpretation of these prognostic factors and the surgical results.

The Effect of Treatment on Mortality in Mild Hypertension: Results of the Hypertension Detection and Follow-up Program

Abstract: In the Hypertension Detection and Follow-up Program, 7825 (71.5 per cent) of the 10,940 participants had diastolic blood pressures averaging between 90 and 104 mm Hg on entry into the study and were designated Stratum 1. Half were referred to their usual source of care in the community (the referred-care group), and half were treated intensively in special clinics (the stepped-care group). Five-year mortality in the Stratum 1 patients given stepped care was 20.3 per cent lower than in those given referred care (P less than 0.01). Particularly noteworthy was the beneficial effect of stepped-care treatment on persons with diastolic pressures of 90 to 104 mm Hg who had no evidence of end-organ damage and were not receiving antihypertensive medication when they entered the study. This subgroup had 28.6 per cent fewer deaths at five years among those treated with stepped care than among those treated with referred care (P less than 0.01). These findings support a recommendation that in patients with mild hypertension, treatment should be considered early, before damage to end organs occurs.

Characterization of HNK-1+ (Leu-7) human lymphocytes. I. Two distinct phenotypes of human NK cells with different cytotoxic capability.

Abstract: Human lymphocytes with NK and K cell activities can be identified by the HNK-1 (Leu-7) monoclonal antibody. In these experiments, subsets of HNK-1+ cells from blood and bone marrow were distinguished by their expression of other cell surface antigens, their morphology, and their NK functional capability. Two-color immunofluorescence analysis revealed that subpopulations of HNK-1+ cells in blood expressed antigens found on mature T cells (e.g., T1, T3, T4, T8), but none expressed antigens characteristic of immature T cells (T6, T9). The majority of HNK-1+ cells (greater than 60%) also expressed a myeloid antigen (M1), whereas a minority (less than 25%) expressed HLA-DR. HNK-1+ cells were separated into T3- and T3+ subsets with the fluorescence-activated cell sorter and analyzed for their morphology and NK cell function. HNK+T3- cells exhibited a high level of NK activity against K562 target cells and contained many cytoplasmic granules. On the other hand, HNK+T3+ cells had low NK activity and a paucity of cytoplasmic granules. The cell sizes of HNK+T3- and HNK+T3+ cells were indistinguishable by light-scatter analysis. When these cell fractions were analyzed further, a reciprocal relationship between T3 and M1 antigen expression was observed. These results thus delineate two distinct subsets of human HNK-1+ cells in blood with different cytotoxic capability: HNK+T3-M1+ and HNK+T3+M1- cells. Analysis of bone marrow cells demonstrated that only 0.7% of the nucleated cells expressed the HNK-1 antigen; virtually all of these cells expressed both the T3 and T8 antigens but lacked the M1 antigen. Thus, a majority of HNK-1+ cell population in blood were T3-M1+, whereas almost all bone marrow HNK-1+ cells were T3+M1-. We propose that these subsets of cells represent different stages in NK cells differentiation.

Complement activation by c-reactive protein complexes*

Abstract: The serum complement system represents a major element of host defense mechanisms against invading pathogens. As such, it functions in concert with other elements of host defense mechanisms both of an immune or a nonimmune nature to preserve and/or restore normal function and health. The initial observations leading to the discovery of complement were made in the late 1800~’-~ when it was found that killing of bacteria by specific antibodies required an additional, nonspecific, thermolabile factor present in all normal sera. This discovery led to the concept that this nonspecific factor assisted the antibodies to carry out their bacteriolytic function. Hence, the term complement which literally means “that which completes or brings to perfection.” As a result of active research in the area during the last 25 years, the original concept of immune bacteriolysis has been completely revised. It is now well established that complement proteins are actually responsible for the formation of lethal cell lesions, whereas the role of antibody is to identify the invading cells and to initiate complement activation. Further, it is also well established that complement can kill bacteria and other pathogens such as protozoa, fungi, and viruses as well as cells of higher organisms even in the absence of antibody. More importantly, it is now well accepted that the contributions of complement to host defense are much broader than killing of cells. The system mediates a number of other functions essential to host defense such as release of histamine from mast cells, chemotactic attraction of phagocytic cells, and opsonization of cells and particles. Complement is a highly organized and tightly regulated system which like other mediator systems in the blood, such as the coagulation system, the fibrinolytic system, and the kinin-generating system, is activated in. a sequential, “cascade-like’’ fashion. Fourteen distinct proteins participate in the activation sequence and at least six other proteins are responsible for the regulation and control of the system (recently reviewed in 4-7). This apparent complexity is contrasted by the functibnal simplicity of the complement system, which becomes evident when its participation in host defense is considered. With few possible exceptions, all the complement-derived biological activities that are relevant to host-defense are derived from two proteins, C3 and C5. These two complement components are structurally very similar. They both have a molecular weight of approximately 185,000.8~’0 Each has two disulfide-linked polypeptide chains termed (Y (110,000) and /3 (75,000). Their biosynthetic precursors are singlepolypeptide chain molecules.yl*lz Finally, available limited amino acid sequence data indicate extensive sequence homologies between C3 and C5.13 The structural similarities between the two proteins make it likely that they represent gene

Bactericidal Activity of Human Lactoferrin: Differentiation from the Stasis of Iron Deprivation

Abstract: Previous studies have demonstrated a direct iron-irreversible inhibition of a variety of microorganisms by human apolactoferrin. The present study compared the bactericidal effects of lactoferrin on Streptococcus mutans with the bacteriostatic effects of iron deprivation. Growth (as determined by change in optical density) and macromolecular synthesis, as determined by incorporation of 14C-labeled uracil, thymidine, and lysine, were inhibited by incubation of washed exponential-phase S. mutans NCTC 10449 with purified human apolactoferrin. Similarly, apolactoferrin inhibited glucose uptake and metabolism. Iron-saturated lactoferrin had no effect on bacterial growth or metabolism and was capable of serving as a source of iron in iron-depleted medium. S. mutans failed to grow, and there was no indication of macromolecular synthesis in iron-depleted partially defined medium; however, glucose metabolism continued, though at a reduced rate, and viability was retained for 72 h. There was no detectable metabolism of glucose by cells maintained for 18 h in iron-free medium. Metabolism was restored by transfer of iron-depleted S. mutans to iron-complete medium. This was in contrast to the irreversible inhibition by lactoferrin after 1 h of incubation. Inhibition could not be reversed by removal of cell surface-associated lactoferrin as detected by rhodamine isothiocyanate-labeled antilactoferrin. This inhibition of metabolism and rapid loss in viability observed with lactoferrin treatment suggest that lactoferrin has a direct bactericidal effect on S. mutans that cannot be attributed to simple iron deprivation.

Anorectal and Vaginal Carriage of Group B Streptococci During Pregnancy

Abstract: A longitudinal prospective study of carriage of group B streptococci during pregnancy was conducted in 2,540 women over a three-year period. Carriage was documented in 18% of the women by anorectal culture, in 4% by vaginal culture, and in 13% by simultaneously obtained anorectal and vaginal cultures (overall carriage rate, 35%). The rate and pattern of carriage were nearly identical from year to year. In sequential cultures in the second and third trimesters of 754 women, carriage rates were 31% and 28%, respectively; only 17% of the women were carriers in both trimesters. (1) Persistence of carriage was most common when the initial anorectal swabs were positive, (2) spread from the intestinal tract to the vagina occurred, and (3) the intestinal tract was commonly the primary site of acquisition in patients with previously negative cultures. The intestinal tract appears to be a primary reservoir for group B streptococci and the likely source of vaginal or urogenital colonization in pregnant women.

Late survival and symptoms after repair of tetralogy of Fallot.

Abstract: The long-term results of 414 patients who underwent repair of tetralogy of Fallot between 1967 and 1977 were studied and correlated with the results of others. There were nine late deaths (8-year actuarial survival 95.8%). Six of the deaths wee directly related to the malformation or its treatment. Eight patients (2.4%) required reoperation. Ten patients (4.8%) had arrhythmic symptoms. Eight (3.1%) had congestive heart failure that required treatment. The risk factors associated with late events of all types, including death, were: older age at repair, a high mean ratio of peak systolic right-to-left ventricular pressures (PLV/RV) immediately after repair, and the presence of a Potts anastomosis. Neither a transannular patch nor a previous Blalock-Taussig or Waterson anastomosis was an incremental risk factor. Bacterial endocarditis was not observed. Three hundred seven patients underwent repair primarily or after a single Blalock-Taussig or Waterston shunt and had a PRV/LV of 0.85 or less after repair. Among these selected patients, the actuarial survival was 98.1%, which is still lower than that for the general population (p = 0.12), and freedom from events was 95.9%. Late after repair, PRV/LV was lower by 6 +/- 28% (+/- SD) than PRV/LV immediately after repair (p = 0.03) in the 33 restudied patients with such data. The higher the PRV/LV immediately after repair, the greater the percent reduction.

.beta.-Carbolines: synthesis and neurochemical and pharmacological actions on brain benzodiazepine receptors

Abstract: We have prepared a series of tetrahydro-beta-carbolines (TH beta C), beta-carbolines (beta-C), and other nitrogen heterocycles and evaluated them in vitro with respect to their ability to bind to benzodiazepine receptors. The fully aromatic beta-C's were more potent than their corresponding TH beta C derivatives. When substituents possessing a carbonyl (CO2Me, COCH3, CHO) were introduced at the beta-C 3-position the in vitro potency was augmented. Alcohol substituents (CH2OH, CHOHCH3) demonstrated decreased in vitro potency. The importance of the carbonyl moiety was further demonstrated when beta-carboline-3-carboxylic acid was shown to bind tighter to benzodiazepine receptors at lower pH. A lower pH increases the concentration of the acid and decreases the concentration of the anion. 3-(Hydroxymethyl)-beta-carboline (24), 3-formyl-beta-carboline (25) and 3-acetyl-beta-carboline (27) were benzodiazepine antagonists in vivo. Methyl isoquinoline-3-carboxylate (31a) also had in vitro activity. The same structure-activity relationships seen in beta-C's were also observed for isoquinolines.

Assessing pain behavior: the UAB Pain Behavior Scale.

Abstract: Review of the chronic pain literature reveals that there have been few systematic attempts to devise rating scales which reliably and/or validly quantify pain behavior. The UAB Pain Behavior Scale was designed so that it could be administered rapidly by a variety of pain team personnel without sacrificing interrater reliability. The scale is described along with initial reliability and validity data. A summary of its use with chronic pain patients is presented.

Intraoperative electrophysiologic mapping of the ventricles during sinus rhythm in patients with a previous myocardial infarction. Identification of the electrophysiologic substrate of ventricular arrhythmias.

Abstract: To determine why only some patients with a previous myocardial infarction develop serious or life-threatening ventricular arrhythmias, we performed electrophysiologic ventricular mapping during sinus rhythm in 38 patients (31 men and seven women, mean age 51 years) during open heart surgery for coronary artery disease. Twenty-nine patients had a left ventricular aneurysm or dyskinetic area, eight had an akinetic area, and one had a severe hypokinetic area. Of 21 patients who had documented ventricular arrhythmias, 16 had recurrent, sustained ventricular tachycardia, two had ventricular tachycardia during exercise testing, and three had frequent premature ventricular complexes only. Seventeen patients were free of ventricular arrhythmias.Epicardial mapping was performed in all 38 patients. The endocardium was also mapped in 10 patients. In 20 patients with ventricular arrhythmias, an area of delayed activation (more than 100 msec after onset of the QRS complex) was found. This type of delay was present in only two of the 17 patients without arrhythmias. The mean latest epicardial activation in patients with arrhythmias was 137 ± 21 msec, whereas in patients without arrhythmias, the mean latest epicardial activation was 74 ± 21 msec (p < 0.001). Twenty of the 21 patients with arrhythmias had fractionated electrograms (three exclusively on the endocardium) and 13 patients had double potentials. Fractionation and double potentials were found in only one of the 17 patients without arrhythmias. The area where abnormal electrograms were recorded (i.e., the number of abnormal recording sites) was significantly larger in patients with recurrent sustained ventricular tachycardia than in patients who had premature ventricular complexes only or had no documented arrhythmias. We conclude that in patients with a previous myocardial infarction associated with serious or life-threatening ventricular arrhythmias, areas of significantly delayed epicardial activation, fractionation and double potentials are characteristic findings of ventricular mapping during sinus rhythm, and presumably constitute the substrate for development of these arrhythmias.

Postnatal expansion of the natural killer and keller cell population in humans identified by the monoclonal HNK-1 antibody.

Abstract: Human natural killer (NK) and killer (K) cells were directly enumerated using a monoclonal antibody (HNK-1) and an immunofluorescence assay. The frequency of cells bearing surface HNK-1 antigen was very low in the newborn (less than 1.0%) and increased progressively through childhood and into adult life. This was correlated with an age-related increase in functional NK and K cell activities. Males had a slightly higher proportion of HNK-1+ cells than females. In addition to HNK-1 expression on the surface membrane, a prominent cytoplasmic expression of HNK-1 antigen was found in some but not all surface HNK-1+ cells. The cytoplasmic accumulation of HNK-1 molecules appeared to occur in more mature cells of this lineage.

Effect of the Degree of Prior Cold Work on the Grain Volume Distribution and the Rate of Grain Growth of Recrystallized Aluminum

Abstract: The grain volume distribution of recrystallized aluminum, determined by separating and weighing the individual grains, has been found to be log normal, its spread in size being expressed by the standard deviation of the distribution (In σv), which remains constant during steady state grain growth. The value of In σv is established by the degree of cold working that precedes annealing, being smaller the greater the degree of cold work. Grain growth proceeds the more rapidly the larger the value of In σv that is, the smaller the degree of prior cold work. The distributions of the numbers of faces per grain and of edges per face are also log normal and are proportional to the grain volume distribution. Thus, the relative number of three-edged faces increases with In σv and accounts for the observed increase in the rate of grain growth.

Humor in Management: Prospects for Administrative Practice and Research

Abstract: Humor has been suggested as an effecive management tool. Reviewed in this paper is the existing research on humor appreciation or what is funny to whom; the influence of humor on group characteristics such as cohesiveness, communications, power, and status; and the linkage, if any, between group dynamic variables and human performance. A list of guidelines for management in matching humor with the situation is given, and some priorities are suggested for research.

Protection of mice from infection with streptococcus pneumoniae by anti-phosphocholine antibody.

Abstract: Anti-phosphocholine (PC) antibody mediated protection against many strains of Streptococcus pneumoniae, and hybridoma anti-PC antibodies protected mice from fatal infections with types 1 and 3 S. pneumoniae. Live types 1, 3, 5, 6A, and 19F S. pneumoniae had similar amounts of surface PC accessible to antibody. Furthermore, mice expressing the X-linked immunodeficiency (xid) of the CBA/N strain were found to be more susceptible to infection with S. pneumoniae of types 3, 6A, and 19F than were immunologically normal mice. The only exception to these results was with the type 5 strain, which was highly virulent for both xid and normal mice. In addition, we were unable to protect mice against infection with the type 5 strain by using anti-PC antibody.