Showing papers by "University of Michigan published in 1978"

The lectins : carbohydrate-binding proteins of plants and animals

Abstract: Publisher Summary Lectins play an important role in the development of immunology. Lectins also find application in serological laboratories for typing blood and determining secretor status, separating leucocytes from erythrocytes, and agglutinating cells from blood in the preparation of plasma. They serve as reagents for the detection, isolation, and characterization of carbohydrate-containing macromolecules, including blood-group antigens. In their interaction with saccharides, lectins serve as models for carbohydrate-specific antibodies, with the important advantage to purify lectins in gram quantities. Lectins are classified according to their carbohydrate-binding specificity that includes D-mannose(D-glucose)-binding lectins and 2-acetamido-2-deoxy-D-glucose-binding lectins. The chapter considers only those lectins that have been purified to homogeneity, and studied with regard to their biophysical, biochemical, and carbohydrate-binding specificity. The chapter also describes the cell-binding and biological properties of lectins. The chapter concludes with the description of several glycopeptide structures showing the carbohydrate-binding loci with which various lectins interact.

Spatial autocorrelation in biology: 1. Methodology

Abstract: Spatial autocorrelation analysis tests whether the observed value of a nominal, ordinal, or interval variable at one locality is independent of values of the variable at neighbouring localities. The computation of autocorrelation coefficients for nominal, ordinal, and for interval data is illustrated, together with appropriate significance tests. The method is extended to include the computation of correlograms for spatial autocorrelation. These show the autocorrelation coefficient as a function of distance between pairs of localities being considered, and summarize the patterns of geographic variation exhibited by the response surface of any given variable. Autocorrelation analysis is applied to microgeographic variation of allozyme frequencies in the snail Helix aspersa. Differences in variational patterns in two city blocks are interpreted. The inferences that can be drawn from correlograms are discussed and illustrated with the aid of some artificially generated patterns. Computational formulae, expected values and standard errors are furnished in two appendices.

Spatial autocorrelation in biology: 2. Some biological implications and four applications of evolutionary and ecological interest

Abstract: Spatial autocorrelation analysis tests whether the observed value of a variable at one locality is significantly dependent on values of the variable at neighbouring localities. The method was extended by us in an earlier paper to include the computation of correlograms for spatial autocorrelation. These show the autocorrelation coefficient as a function of distance between pairs of localities, and summarize the patterns of geographic variation exhibited by the response surface of any given variable. Identical variation patterns lead to identical correlograms, but different patterns may or may not yield different correlograms. Similarity in the correlograms of different variation patterns suggests similarity in the generating mechanism of the pattern. The inferences that can be drawn from correlograms are discussed and illustrated. Examination and analysis of variation patterns of several characters or gene frequencies for one population, or of several populations in different places or at different times, permit some conclusions about the nature of the populational processes generating the observed patterns. Autocorrelation analysis is applied to four biological situations differing in the nature of the data (interval or nominal), in the type of grid connecting the localities (regular or irregular), and the field of application (evolution or ecology). The examples comprise genotypes of individual mice, blood group frequencies in humans, gene frequency variation in a perennial herb, and the distribution of species of trees. The implications of our findings are discussed.

Cognitive systems based on adaptive algorithms1

Abstract: The type of cognitive system (CS) studied here has four basic parts: (1) a set of interacting elementary productions, called lassifiers, (2) a performance algorithm that directs the action of the system in the environment, (3) a simple learning algorithm that keeps a record of each classifier's success in bringing about rewards, and (4) a more complex learning algorithm, called the genetic algorithm, that modifies the set of classifiers so that variants of good classifiers persist and new, potentially better ones are created in a provably efficient manner. Two “proof-of-principle” experiments are reported. One experiment shows CS's performance in a maze when it has only the ability to adjust the predictions about ensuing rewards of classifiers (similar to adjusting the “weight” of each classifier) vs. when the power of the genetic algorithm is added. Criterion was achieved an order of magnitude more rapidly when the genetic algorithm was operative. A second experiment examines transfer of learning. Placed in a more difficult maze, CS with experience in the simpler maze reaches criterion an order of magnitude more rapidly than CS without prior experience.

The quality of medical care

Abstract: This article classifies the major approaches to the assessment of the process and outcomes of medical care. The apparent need to safeguard and enhance the quality of care has led to the institution of mechanisms that subject care to constant review so that deficiencies may be found and corrected. The article reviews the developments that led to the involvement of the federal government in this activity through its sponsorship of professional standards review organizations (PSRO's). The major features of the PSRO's are described and their possible effects discussed. It is too early to say how the PSRO's will fare, but should they fail to accomplish their objectives the pressure for more radical solutions will be difficult to resist.

Induced cell aggregation and mating in Streptococcus faecalis: evidence for a bacterial sex pheromone

Abstract: Recipient strains of Streptococcus faecalis produce a trypsin sensitive, heat resistant, nuclease resistant factor, designated clumping-inducing agent (CIA) which causes strains carrying certain conjugative plasmids to aggregate. RNA and protein synthesis but not DNA synthesis are required for aggregation to occur. Recipient filtrates that contain CIA activity also induce donors to mate at high frequencies. Introduction of a transferable plasmid into strains producing CIA dramatically reduces the amount of CIA activity produced by the strain but allows the strain to respond to exogenously added CIA. Our data suggest that CIA represents a bacterial sex hormone (pheromone).

The evolution of mating strategies in bullfrogs, rana catesbeiana.

Abstract: Mating system theory is undergoing considerable revision and elaboration (for example: Fisher, 1958; Brown, 1964; Williams, 1966, 1975; Orians, 1969; Cody, 1971; Trivers, 1972; Alexander, 1975; Emlen and Oring, 1977; Alexander and Borgia, 1978). These theories are based upon Darwin's (1871) concept of how natural selection acts within and between the sexes: intrasexual selection, sexual competition between members of the same sex for mates, and intersexual selection, in which one sex is the selective agent for the other. Unfortunately, adequate data to test these theories are lacking for most organisms (but see Bateman, 1948; Savage, 1961; LeBoeuf, 1974; Chagnon, 1974; Jenni, 1974). In this paper, I present necessary data on how mating success varies within and between the sexes to test existing theories of sexual selection for one species, the bullfrog, Rana catesbeiana, and I extend current theoretical considerations to include how age should influence alternative male mating strategies. Anurans are excellent animals to test theoretical predictions of sexual selection: since males fertilize eggs externally, there is no doubt about male parentage and, thus, relative male mating success. Such high confidence of paternity is lacking for most species with internal fertilization. Additional attributes of bullfrogs which make a study technically possible include (a) a tendency for chorusing males to form relatively dense aggregations thus facili-

Neural Lateralization of Species-Specific Vocalizations by Japanese Macaques (Macaca fuscata)

Abstract: Five Japanese macaques and five other Old World monkeys were trained to discriminate among field-recorded Japanese macaque vocalizations. One task required discrimination of a communicatively relevant acoustic feature ("peak"), and a second required discrimination of an orthogonal feature of the same vocalizations ("pitch"). The Japanese animals more proficiently discriminated the peak feature when stimuli were presented to the right ear (primarily left cerebral hemisphere), as opposed to the left ear (primarily right hemisphere). In discriminating the pitch feature, the Japanese animals either showed (i) a left-ear processing advantage or (ii) no ear advantage. The comparison animals, with one exception, showed no ear advantage in processing either feature of the vocalizations. The results suggest that Japanese macaques engage left-hemisphere processors for the analysis of communicatively significant sounds that are analogous to the lateralized mechanisms used by humans listening to speech.

Counterfactuals and Two Kinds of Expected Utility

Abstract: We begin with a rough theory of rational decision-making In the first place, rational decision-making involves conditional propositions: when a person weighs a major decision, it is rational for him to ask, for each act he considers, what would happen if he performed that act It is rational, then, for him to consider propositions of the form ‘If I were to do a, then c would happen’ Such a proposition we shall call a counterfactual, and we shall form counterfactuals with a connective ‘☐→' on this pattern: ‘If I were to do a, then c would happen’ is to be written ‘I do a ‘☐→' c happens’

Fast-start Performance and Body Form in Seven Species of Teleost Fish

Abstract: Fast-start kinematics and performance were determined for Etheostoma caeruleum, Cottus cognatus, Notropis cornutus, Lepomis macrochirus, Perca flavescens, Salmo gairdneri and a hybrid Esox sp. at an acclimation and test temperature of 15 °C. Normal three-stage kinematic patterns were observed for all species. Fast-start movements were similar in all species, except Lepomis , which had slightly higher amplitudes than expected for its length. The duration of kinematic stages was a major variable among the seven species but was a linear function of length. Acceleration rates were not functions of size. Maximum acceleration rates ranged from 22-7 to 39-5 m. s−2 with mean rates from 6.1 to 12.3 m.s−2 averaged to the completion of kinematic stage 2. Maximum velocity and distance covered in each fast-start stage varied among species but were related to length. Fast-start performance depended primarily on compromise between muscle mass as a percentage of body mass, and lateral body and fin profile. Optimal profiles provide large depth distant from the centre of mass to maximize thrust, and anterior depth enhancement to minimize recoil. The body form of Lepomis is considered optimal for multiple swimming modes.

Bacteriology of human experimental gingivitis: effect of plaque age.

Abstract: Twenty-five subjects with previously excellent hygiene and healthy gingiva developed heavy plaque accumulations and bleeding or nonbleeding gingivitis about certain papilla after 21 days of no oral hygiene. Gingival marginal plaque about a single papilla was collected at 0, 1, 2, and 3 weeks of no oral hygiene in each subject. The plaque was dispersed, serially diluted, and plated on MM10 sucrose agar in an oxygen-free atmosphere. From 50 to 100 colonies from a single high-dilution plate were characterized for each sample. Over 8,500 isolates were partially characterized and placed into one of 29 taxonomic species or groups. The flora was predominantly gram-positive at all time periods. Streptococcal species dominated in the 0- and 1-week-old plaques, i.e. 62 and 43% of the colonyforming units (CFU), but dropped to 26 to 32% of the CFU in the 2- and 3-week-old plaques. Actinomyces species dominated in the older plaques, i.e., 40 to 50% of the CFU. Actinomyces israelii was the most prominent species in the older plaques. Veillonella accounted for 15 to 20% of the CFU at all time periods. Although the other gram-negative species increased with time, collectively they averaged less than 5% of the CFU at week 3. The shift from a Streptococcus-dominated plaque to an Actinomyces-dominated plaque was the most striking microbial change observed as the plaque aged.

Presynaptic alpha-receptor subsensitivity after long-term antidepressant treatment

Abstract: After 3 weeks of twice-daily administration of desipramine to rats, the frequency-response curve for field stimulation of adrenergic neurons in isolated left atrial strips was shifted markedly to the left and the efflux of [3H]norepinephrine was enhanced greatly. After 1 day of treatment, only slight shifts in the frequency-response curve and small increases in [3H]norepinephrine efflux occurred although inhibition of [3H]norepinephrine uptake was already maximal, and phenoxybenzamine caused a further shift to the left in the frequency-response curve similar to that which occurred after 3 weeks of desipramine treatment alone. A gradual decrease in the sensitivity of the presynaptic alpha receptor would explain the delay in the onset of the linical effect of the tricyclic antidepressants.

Phenolic Content of Vegetation in Two African Rain Forests: Ecological Implications

Abstract: Mature leaves of abundant trees in rain-forest vegetation on acid whitesand soils of the Douala-Edea reserve, Cameroon, contain approximately twice the concentration of phenolic compounds found in similar rain-forest vegetation on lateritic soils of the Kibale forest, Uganda. Phenolics are the most widespread class of ecologically important plant secondary compounds. This study provides support for the hypothesis that vegetation on low-nutrient soils contain relatively high concentrations of chemicals deterrent to herbivores and pathogens. Unlike the two species of Colobus monkeys found in Kibale forest, black Colobus monkeys (Colobus satanas) in the Douala-Edea reserve avoid the leaves of almost all abundant tree species in the area, selectively feeding on leaves of almost all relatively rare components of the vegetation (deciduous trees and second-growth vines). Unlike any other colobine studied to date, black Colobus in the Douala-Edea researve feed heavily on seeds, which contain lower concentrations of phenolic compounds than do leaves in this site.

Prediction of metabolic rates for manual materials handling jobs

Abstract: A new approach for estimating metabolic rates for manual materials handling jobs is presented. This approach was applied to 48 different jobs. The model validation showed a correlation coefficient of 0.95 between the measured and predicted metabolic rates. The coefficient of variation (standard error/sample mean) was 10.2 percent.

Morphometric Analysis of Follicular Development In the Rat

Abstract: Ovarian follicular development was examined in she cycling rat using histological techniques The number and size distribution of follicles was determined for each day of the estrous cycle While the number of follicles in the early stages of growth did not appear to vary dramatically throughout the estrous cycle the final stages of growth and differentiation showed great variation throughout she cycle No follicles of 390-500 &m were seen on proestrus bus many appeared the next day suggesting that there was a discontinuous movement of follicle, into she largest size range Follicular atresia was most marked in follicles 200-400Mm in diameter suggesting that there may be a critical stage during follicular development when, unless rescued most follicles become asretic

Who is responsible? Toward a social psychology of responsibility attribution.

Abstract: The currently dominant psychological model of responsibility attribution is criticized and expanded upon from a sociological perspective. It is argued that responsibility judgments entail consideration of both what the actor did and what the actor was supposed to do: i.e., both physical deeds and social roles. Including roles in a responsibility attribution model provides: (I) a coherent account of alternative meanings of responsibility itself; (2) a social psychological approach that is congruent with rules actually followed in adult sanctioning judgments; and (3) an opportunity for social psychologists to study the crucial dichotomy of authoritative versus subordinate roles. Roles are interpreted attributionally as normative contexts within which actions are evaluated, rather than as external or situational constraints on action. In general, it is suggested that accepting a role demand as normative may evoke a purposive attribution process, labeled here as ' 'motive grammar''; rejecting the role demand may be accompanied by a causal attribution process, "consequence grammar." The paper concludes with suggestions for future research possibilities.

The clinical significance of bundle branch block complicating acute myocardial infarction. 1. Clinical characteristics, hospital mortality, and one-year follow-up.

Abstract: To provide an understanding of the clinical characteristics of patients with acute myocardial infarction (MI) and bundle branch block, experience from five centers was accumulated. Patients in whom bundle branch block first appeared after the onset of cardiogenic shock were excluded. In 432 patients, the most common types of block were left (38%) and right with left anterior fascicular block (34%). In 42% of the patients, bundle branch block was new. Progression to high degree (second or third degree) atrioventricular (AV) block via a Type II pattern occurred in 22% of the patients. Hospital and first year follow-up mortality rates were 28% and 28%, respectively. Only 46% of the patients developed pulmonary edema or shock (Killip Class III or IV), and hospital mortality was related to the amount of heart failure (8%, 7%, 27%, 83% for Killip Classes I-IV, respectively). Patients with progression to second degree or third degree AV block via a Type II pattern had increased hospital mortality compared with patients without this complication (47% vs 23%, P less than 0.001). In the absence of pulmonary edema or shock, patients with Type II second degree or third degree AV block still had a higher mortality rate than patients without advanced AV block (31% vs 2%, P less than 0.005), with nearly all the deaths due to abrupt development of AV block. Thus, in many patients MI with bundle branch block is associated with severe heart failure. However, this was not true for a majority of the patients, in whom therapy aimed at preventing morbidity and mortality due to the bradyarrhythmia of advanced AV block might be beneficial.

Toward a general theory of infantile attachment: A comparative review of aspects of the social bond.

Abstract: This critical appraisal of contemporary interpretations in the area of infantile attachment begins with an outline of the principal features of the Bowlby-Ainsworth ethological theory, the instrumental/operant learning theory of Gewirtz, and Hoffman's classical conditioning model. Some attention is also given to Cairns's contiguity learning analysis and the Hoffman-Solomon opponentprocess model Discussion of these theories is followed by a review of representative data from infants at four phyletic levels (precocial birds, dogs, monkeys, and human beings), with an emphasis on three aspects of social bonding: (a) the formation and persistence of social ties in the infant under conditions of maltreatment, (b) the role of the attachment object in the adjustment of the infant to the broader environment (the so-called secure base effect), and (c) the infant's reaction to involuntary separation from the attachment object. An attempt is made to judge how well each of the interpretations accounts for all or part of the data, with the conclusion that current theories do not accord completely with documented attachment phenomena. The following criticisms are highlighted: Ethological theory emphasizes that infants' behavior systems have been shaped by the ordinarily expectable environment and depend on that environment for their functioning, yet infants of many species form bonds to objects not typical in any species' environment, or even to sources of maltreatment. Learning theory is faulted for making predictions contradicted by the maltreatment data and for a lack of formal mechanisms to account for the secure base and separation effects. The contiguity analysis is criticized for its inability to account for the emergence of certain response patterns during separation, and the opponent-process model is called into question because of its failure to fit important affective dynamics of social separation (a central focus of this theory). Recommendations for future theories of attachment are offered.