Showing papers by "Tulane University published in 1989"

Effects of Procedural and Distributive Justice on Reactions to Pay Raise Decisions

Abstract: We conducted a survey to examine the impact of distributive and procedural justice on the reactions of 217 employees to decisions about pay raises. Distributive justice accounted for more unique va...

An African primate lentivirus (SIVsm) closely related to HIV-2

Abstract: THE ancestors of the human immunodeficiency viruses (HIV-1 and HIV-2) may have evolved from a reservoir of African non-human primate lentiviruses, termed simian immunodeficiency viruses (SIV)1. None of the SIV strains characterized so far are closely related to HIV-12–6. HIV-2, however, is closely related to SIV (SIVmac) isolated from captive rhesus macaques (Macaca mulatta)7. SIV infection of feral Asian macaques has not been demonstrated by serological surveys8,9. Thus, macaques may have acquired SIV in captivity by cross-species transmission from an SIV-infected African primate. Sooty mangabeys (Cercocebm atys), an African primate species indigenous to West Africa, however, are infected with SIV (SIVsm) both in captivity9–11and in the wild (P. Fultz, personal communication). We have molecularly cloned and sequenced SIVsm and report here that it is closely related to SIVmac and HIV-2. These results suggest that SIVsm has infected macaques in captivity and humans in West Africa and evolved as SIVmac and HIV-2, respectively.

A Prospective Study of Human Immunodeficiency Virus Type 1 Infection and the Development of AIDS in Subjects with Hemophilia

Abstract: We evaluated a multicenter cohort of 1219 subjects with hemophilia or related disorders prospectively, focusing on 319 subjects with documented dates of seroconversion to human immunodeficiency virus type 1 (HIV-1). The incidence rate of the acquired immunodeficiency syndrome (AIDS) after seroconversion was 2.67 per 100 person-years and was directly related to age (from 0.83 in persons 1 to 11 years old up to 5.66 in persons 35 to 70 years old; Ptrend = 0.00003). The annual incidence of AIDS ranged from zero during the first year after seroconversion to 7 percent during the eighth year, with eight-year cumulative rates (±SE) of 13.3±5.3 percent for ages 1 to 17, 26.8±6.4 percent for ages 18 to 34, and 43.7±16.4 percent for ages 35 to 70. Serial immunologic and virologic markers (total numbers of CD4 lymphocytes, presence of serum interferon or HIV-1 p24 antigen, and low or absent serum levels of anti-p24 or anti-gp120) predicted a high risk for the subsequent development of AIDS. Adults 35 to 70 ...

Identification of an AUUUA-specific messenger RNA binding protein

Abstract: An important control point in gene expression is at the level of messenger RNA (mRNA) stability. The mRNAs of certain regulatory cellular proteins such as oncogenes, cytokines, lymphokines, and transcriptional activators are extremely labile. These messages share a common AUUUA pentamer in their 3' untranslated region, which confers cytoplasmic instability. A cytosolic protein was identified that binds specifically to RNA molecules containing four reiterations of the AUUUA structural element. This protein consists of three subunits and binds rapidly to AUUUA-containing RNA. Such protein-RNA complexes are resistant to the actions of denaturing and reducing agents, demonstrating very stable binding. The time course, stability, and specificity of the protein-AUUUA interaction suggests the possibility that the formation of this complex may target susceptible mRNA for rapid cytoplasmic degradation.

Perinatal transmission of the human immunodeficiency virus type 1 to infants of seropositive women in Zaire.

Abstract: To examine perinatal transmission of the human immunodeficiency virus type 1 (HIV-1) in Zaire, we screened 8108 women who gave birth at one of two Kinshasa hospitals that serve populations of markedly different socioeconomic status. For up to one year, we followed the 475 infants of the 466 seropositive women (5.8 percent of those screened) and the 616 infants of 606 seronegative women matched for age, parity, and hospital. On the basis of clinical criteria, 85 of the seropositive women (18 percent) had the acquired immunodeficiency syndrome (AIDS). The infants of seropositive mothers, as compared with those of seronegative mothers, were more frequently premature, had lower birth weights, and had a higher death rate in the first 28 days (6.2 vs. 1.2 percent; P less than 0.0001). The patterns were similar at the two hospitals. Twenty-one percent of the cultures for HIV-1 of 92 randomly selected cord-blood samples from infants of seropositive women were positive. T4-cell counts were performed in 37 seropositive women, and cord blood from their infants was cultured. The cultures were positive in the infants of 6 of the 18 women with antepartum T4 counts of 400 or fewer cells per cubic millimeter, as compared with none of the infants of the 19 women with more than 400 T4 cells per cubic millimeter (P = 0.02). One year later, 21 percent of the infants of the seropositive mothers had died as compared with 3.8 percent of the control infants (P less than 0.001), and 7.9 percent of their surviving infants had AIDS. We conclude that the mortality rates among children of seropositive mothers are high regardless of socioeconomic status, and that perinatal transmission of HIV-1 has a major adverse effect on infant survival in Kinshasa.

A formalin-inactivated whole SIV vaccine confers protection in macaques

Abstract: A vaccine against human immunodeficiency virus (HIV) would be highly effective in stopping the acquired immunodeficiency syndrome (AIDS) epidemic. A comprehensive evaluation of potential vaccine methodologies can be made by means of the simian model for AIDS, which takes advantage of the similarities in viral composition and disease potential between simian immunodeficiency virus (SIV) infection of rhesus macaques and HIV infection in humans. Immunization with a formalin-inactivated whole SIV vaccine potentiated with either alum and the Syntex adjuvant threonyl muramyl dipeptide (MDP) or MDP alone resulted in the protection of eight of nine rhesus monkeys challenged with ten animal-infectious doses of pathogenic virus. These results demonstrate that a whole virus vaccine is highly effective in inducing immune responses that can protect against lentivirus infection and AIDS-like disease.

Role Overload, Role Conflict, and Stress: Addressing Consequences of Multiple Role Demands

Abstract: Previous studies provide contradictory evidence regarding the relationship between multiple role demands and psychological well-being Some of the inconsistency in this research may stem from the conceptual confusion surrounding the concepts of role overload and role conflict This study clarifies these concepts in order to examine their effects on stress-related outcomes A model is tested which specifies that role overload (eg, domestic and paid work time expenditures) and role conflict (eg, perceptions of work-family interference) affect satisfaction with various role domains (eg, job satisfaction and marital satisfaction) which in turn influences stress (eg, psychophysical symptoms and well-being) Covariance structure models are estimated for employed, currently married women and men As expected, marital and job satisfaction strongly affect both psychophysical symptoms and well-being Findings also suggest that role conflict decreases both sexes' job satisfaction and men's marital satisfaction and increases zvomen's psychophysical symptoms Role overload does not affect role satisfaction or stress for either sex It is concluded that perceived role conflict decreases wvomen's psychological health, but role overload does not

Stress and coping among parents of handicapped children: a multidimensional approach.

Abstract: The relations of child characteristics, family social network, parent belief systems, and coping styles to parent outcome were examined with parents of 48 young handicapped children. Child characteristics predicted mothers' and fathers' parenting stress and fathers' psychological distress. Parental belief systems predicted all three parent outcomes for mothers and fathers. Coping styles predicted psychological distress and fathers' family adjustment. Social network predicted family adjustment and fathers' psychological distress. Psychological distress was low in mothers who had either a positive belief system or a noncritical family network. Findings support the value of a multidimensional examination of family characteristics that mediate the impact of a child's handicap.

Managerial responsibilities and procedural justice

Abstract: This article identifies managerial responsibilities associated with ensuring fairness in the implementation of decision-making procedures in organizations. These responsibilities include giving adequate consideration to employees' viewpoints, suppressing biases, applying decision-making criteria consistently, providing timely feedback, giving justification, being truthful in communication, and treating employees with courtesy and civility. The article concludes with a discussion of the theoretical and practical implications of this analysis for procedural justice in organizations

Job Attitude Organization: An Exploratory Study1

Abstract: An exploratory study was conducted to examine the organization of three often used measures of job satisfaction. Employing a convenient sample of 144 workers, who also were enrolled in evening graduate school courses, relationships between these job satisfaction measures and affective (positive and negative) and cognitive attitudinal components were assessed. The job satisfaction measures were found to vary considerably in terms of their affective and cognitive content. These results were discussed in terms of their relevance to the study of job attitudes.

Characteristics and distribution of receptors for [D-TRP6]-luteinizing hormone-releasing hormone, somatostatin, epidermal growth factor, and sex steroids in 500 biopsy samples of human breast cancer.

Abstract: Binding capacities and apparent dissociation constants of receptors for [D-Trp6]-luteinizing hormone-releasing hormone [( D-Trp6]-LH-RH), somatostatin (SS-14), epidermal growth factor (EGF), and estrogen and progesterone were determined in 500 breast cancer specimens using multipoint assays. Specific binding sites greater than 10 fmol/mg cytosol protein for estrogen were found in 408 carcinomas (81.6%), and for progesterone in 340 specimens (68%). High affinity EGF receptors were present in membrane preparations from 335 samples (67%). In 260 of 500 samples (52%), two classes of [D-Trp6]-LH-RH membrane receptor sites were also detected, one class showing high affinity and low capacity, and the other class showing low affinity and high capacity; 178 biopsy samples (35.6%) exhibited binding sites for SS-14. Statistically significant inverse correlations were found between the binding capacities of estrogen and EGF receptors as well as between Bmax of progesterone and EGF receptors. Significant positive correlations were demonstrated between binding capacities of estrogen and progesterone and between Bmax of high affinity and low affinity binding sites of [D-Trp6]-LH-RH receptors. However, no correlation was found between the dissociation constants of different receptor sites in human breast cancer specimens. These results demonstrate that numerous human breast cancers, in addition to receptors for estrogen and progesterone, also show binding sites for EGF, [D-Trp6]-LH-RH and SS-14. The methods described herein permit a routine quantification of receptor sites for [D-Trp6]-LH-RH, SS-14, and EGF in membrane preparations of biopsy samples of breast cancer and can be used in conjunction with the determination of estrogen and progesterone receptors in nuclear-cytosolic extracts. The simultaneous measurements using a microanalytic approach allow the determination of peptide and steroid hormone receptors that might be involved in the response mechanisms of human breast cancer. It should be possible to correlate the levels of these receptors with clinical parameters to better identify endocrine-responsive neoplasms. This approach might be useful to guide a rational hormonal therapy in women with breast cancer.

Interleukin-1 beta increases prostaglandin E2 in rat astrocyte cultures: modulatory effect of neuropeptides.

Abstract: Recombinant human interleukin-1 beta (IL-1β) significantly increased prostaglandin E2 (PGE2) in a dose-dependent manner in rat astrocyte culture. The minimum effective dose of IL-Iβ was 10-10M. IL-1 α also increased PGE2, but at a higher concentration. The minimum effective dose of IL-lα was 10-8M, indicating it to be 100-fold less effective than IL-Iβ. On the other hand neither IL-Iβ nor IL-1 α increased PGE2 production by neuron cultures at any concentration tested. PGE2 response to IL-Iβ was suppressed by simultaneous addition of CRH, somatostatin-14 and LHRH, while these neuropeptides alone did not alter the basal PGE2 levels. Substance P, vasoactive intestinal polypeptide and ±-MSH altered neither basal nor IL-1β-induced increase in PGE2 levels. Angiotensin II (All) alone also increased PGE2 in cultured astrocytes. Combined addition of All and IL-Iβ induced a synergistic effect in increasing PGE2 levels. The direct action of IL-Iβ on astrocyte culture suggests that astrocytes may be the target cells ...

Generation of human EEG by a combination of long and short range neocortical interactions.

Abstract: A theory of neocortical interactions is developed involving both local delays (PSP rise and decay times) and global delays due to finite velocity of action potentials in corticocortical fibers. The theory is based on plausible assumptions regarding input/output relations in neocortical columns and realistic neural parameters. The simultaneous existence of short wavelength waves propagating away from multiple epicenters and long wavelength standing waves due to global boundary conditions is predicted. Both phenomena appear to have dominant oscillation frequencies in the general range of observed EEG phenomena in humans. A mechanism by which removal of diffuse input from the reticular formation may cause an abrupt drop in EEG frequency (as in the transition from the awake to sleeping state) is postulated.

Covalent DNA Damage in Tissues of Cigarette Smokers as Determined by 32P-Postlabeling Assay

Abstract: Covalent DNA addition products (adducts) formed by the reaction of chemical carcinogens or their metabolites with DNA are critically involved in the initiation of chemical carcinogenesis and may serve as molecular markers and dosimeters for environmental carcinogen exposures. Using a highly sensitive 32P-postlabeling assay for DNA adduct analysis, we studied DNA damage elicited by cigarette smoke in tissues of smokers. A multitude of characteristic smoking-induced, presumably aromatic DNA adducts were found to occur in a dose- and time-dependent manner in the lung, bronchus, and larynx of smokers with cancer of these organs and to decline only slowly after cessation of smoking. Low levels of adducts appeared to persist for up to 14 years in the lungs of exsmokers with high previous exposures. These results corroborate data of epidemiological studies showing that the lung cancer risk and mortality of smokers increase with the intensity and duration of smoking and decline only slowly after cessation of smoking. Tissue distribution studies in autopsy samples revealed the presence of smoking-associated DNA lesions also in the kidney, bladder, esophagus, heart, ascending aorta, and liver. The most extensive DNA damage was found in lung and heart, i.e., 1 aromatic adduct in about 10(7) DNA nucleotides. Our results suggest that cigarette smoking-induced DNA adduct formation is causally related to cancer in the target organs.

Misalliances in the Barrow Alcohol Study.

Abstract: The Center for Research on the Acts of Man conducted a survey of the use of alcohol among the Inupiat of Barrow, Alaska, in 1979. The study resulted in grievances among many individuals and institutions associated with the community. In a retrospective analysis of the factors contributing to these misalliances, the author raises important ethical and procedural questions to be considered carefully in future projects of this nature.

How Investment Bankers Determine the Offer Price and Allocation of New Issues

Abstract: Investigates how investment bankers use indications of interest from client investors to price and allocate new issues. Investors who buy initial public offerings (IPOs) can achieve sizable early returns. Recent research rationalizes this apparent contradiction to market efficiency as a response to asymmetric information; but this research ignores how information frictions bear on IPO marketing. This work analyzes underwriters' IPO marketing and shows how the information it yields is used in IPO pricing and allocation. By means of this access to investors, underwriters can reduce IPO underpricing. Develops a model of the premarket as an auction constructed to induce asymmetrically informed investors to reveal what they know to the underwriter. The model consists of a private firm offering a fixed fraction of its future cash flows and a population of investors, each of whom has a single piece of information, and market that proceeds in two stages. Two types of information frictions and two sets of rules for auctions are identified. Underpricing is a natural consequence of the premarket auction. IPO prices must be set low to provide compensatory profit to investors for revealing information. By selling repeatedly to the same investors, the underwriter can reduce required underpricing and change the rules of the auction in favor of the issuing firm. The analysis yields a number of empirical implications: that new issues will be underpriced and that priority in distribution will be given to the underwriter's regular investors. Also finds that the type of underwriting contract is affected by the tension between an underwriter's likeliness to pre-sell an issue and an issuing firm's desire to obtain the greatest proceeds. The decision to use a firm-commitment or best-efforts underwriting contract reflects the desire to control the choice of rules. The former promotes underpricing; the latter reduces underpricing for firms facing high price uncertainty.

Yield behavior of bovine cancellous bone.

Abstract: The compressive yield strain was measured for 61 specimens of bovine cancellous bone from three distal femora. There was no significant relationship (p = 0.08, R2 = 0.051) between yield strain and the degree of trabecular orientation. There was a significant positive correlation (p less than 0.00001, R2 = 0.319) between yield strain and structural (apparent) density and significant negative correlation (p less than 0.0025, R2 = 0.145) between yield strain and bone density. Yield strain correlated best with bone solid volume fraction Vv (epsilon y = 0.592 +2- 1.446vv, R2 = 0.337). The quantity, yield strain, is highly dependent on specific definitions of the yield point and the point of zero strain. For this study the yield point was defined by a 0.0003 offset criterion, and the point of zero strain was defined as the point where the tangent at 15 percent of yield crosses zero. The results using these definitions were compared with results using yield strain values determined by other definitions of the yield point and zero strain. The correlations between yield strain and trabecular orientation, structural density and bone density changed very little for differing definitions of yield. The results suggest that yield strain in cancellous bone is isotropic or independent of textural anisotropy, so the yield behaviour may be characterized by a maximum strain yield criterion. The results also suggest that the primary mode of yield in cancellous bone is buckling of the trabeculae.

Antibiotic Prophylaxis in Surgery

Abstract: Scientific studies conducted during the last 10 years have resulted in a great improvement of our approach to the appropriate use of prophylactic antibiotics in the surgical patient. Errors of the past including faulty timing of the initial dosage as well as prolonged duration of prophylaxis have largely been remedied. Present studies are designed to define the patients within the various subsets of diseases or surgical procedures who are at greatest risk of infection. It is these patients who can be expected to benefit most from the efficacious use of prophylactic antibiotics as well as other preventative measures.

Complications with the variable spinal plating system.

Abstract: From January 1986 to June of 1987, 40 patients underwent transpedicle fixation and fusion using the variable spinal plate system. Nineteen patients had undergone surgery at the same level or levels, and 21 patients had undergone no previous surgery. Diagnostic categories include spondylolisthesis, t

Receptors for luteinizing hormone-releasing hormone, somatostatin, prolactin, and epidermal growth factor in rat and human prostate cancers and in benign prostate hyperplasia.

Abstract: Using sensitive multipoint micromethods, we estimated membrane receptors for [D-Trp6]-luteinizing hormone-releasing hormone ([ D-Trp6]-LH-RH), somatostatin (SS-14), human prolactin (hPRL), and epidermal growth factor (EGF) in experimental Dunning rat prostate cancers and in samples of normal human prostate, benign prostatic hyperplasia (BPH), and human prostate cancer (PC) obtained from biopsy, after prostatectomy, or at autopsy. In the Dunning R-3327 rat prostate adenocarcinoma specimens, the receptors were characterized in untreated animals and following in vivo treatment with microcapsules of the agonist [D-Trp6]-LH-RH and the somatostatin analog RC-160. Two populations of binding sites were found for [D-Trp6]-LH-RH, one with high affinity and low capacity and another with low affinity and high capacity. Treatment with [D-Trp6]-LH-RH and RC-160 alone or with the combination of these analogs increased the binding capacity (Bmax) of the low-affinity binding sites for [D-Trp6]-LH-RH and decreased Bmax for hPRL and EGF. Therapy with [D-Trp6]-LH-RH also reduced Bmax of SS-14 binding and dissociation binding constant of high-affinity binding sites for [D-Trp6]-LH-RH, whereas administration of RC-160 or the combination treatment with both analogs increased Bmax of SS-14 binding. These findings are compatible with the view that analogs of LH-RH and SS-14 might exert some direct inhibitory effects on the Dunning prostate cancer. Among 13 human BPH samples examined, only one had receptors for [D-Trp6]-LH-RH, and seven specimens exhibited binding for prolactin. [D-Trp6]-LH-RH receptors were found in all seven samples of human PC but not in any of the eight specimens of normal human prostate. All samples of normal human prostate, BPH, and human PC exhibited binding sites for EGF but not for SS-14. Our findings on the membrane receptors in the human and rat prostate cancers raise the intriguing possibility that LH-RH, acting as a growth factor, along with EGF and prolactin, might be involved in complex interactions that contribute to the promotion of prostate cancer in man.