Showing papers by "Tufts University published in 1979"

Post‐Divorce Family Relationships as Mediating Factors in the Consequences of Divorce for Children

Abstract: In this study, the psychological structure of the family after divorce is seen as mediating the impact of divorce upon children. Divorce affects primary bonds with parents, presents challenges to conceptions of social reality, and creates stress which interferes with normal development. The effects of divorce upon child behavior (peer relations, stress, aggression, work effectiveness at school) were examined through two contrasting research strategies: 1) a comparison of the behavior of children in divorced and intact families, and 2) analysis of the association between family processes and child outcomes in intact and divorced families. Family processes examined were: (a) the affective relationships between the father and mother, (b) the affective relationships between the child and each parent separately, and (c) for divorced families, the amount of contact between child and non-custodial parent. For divorced and intact groups combined, the relationships among family members appeared to be more potent influences on child behavior than was marital status. The negative effects of divorce were greatly mitigated when positive relationships with both parents were maintained. The child's relationship with the non-custodial parent (father) was as important as the continuing relationship with the mother. Implications for research and for public policy are discussed.

Carotenoid protection against oxidation

Abstract: Based on experimental observations made in photosynthetic organisms which lacked colored carotenoid pigments, a hypothesis was developed that these pigments could serve as protective agents against photosensitized oxidations. Over the last 20 years, many workers have confirmed this hypothesis and have extended the observations to non-photosynthetic bacteria, plants and animals. It has also been possible to demonstrate carotenoid protection in in vitro systems. This article reviews the major mechanisms whereby carotenoid pigments protect cells against harmful photosensitized oxidations. The mechanisms include: (1) Carotenoid quenching of triplet sensitizers. (2) Carotenoid quenching of O2 (1δg). (3) Carotenoid inhibition of free radical reactions.

On the demystification of mental imagery

Abstract: What might a theory of mental imagery look like, and how might one begin formulating such a theory? These are the central questions addressed in the present paper. The first section outlines the general research direction taken here and provides an overview of the empirical foundations of our theory of image representation and processing. Four issues are considered in succession, and the relevant results of experiments are presented and discussed. The second section begins with a discussion of the proper form for a cognitive theory, and the distinction between a theory and a model is developed. Following this, the present theory and computer simulation model are introduced. This theory specifies the nature of the internal representations (data structures) and the processes that operate on them when one generates, inspects, or transforms mental images. In the third, concluding, section we consider three very different kinds of objections to the present research program, one hinging on the possibility of experimental artifacts in the data, and the others turning on metatheoretical commitments about the form of a cognitive theory. Finally, we discuss how one ought best to evaluate theories and models of the sort developed here.

Differential symptom reduction by drugs and psychotherapy in acute depression.

Abstract: • A randomized, controlled trial compared the combination of amitriptyline hydrochloride and short-term interpersonal psychotherapy, either treatment alone, and a nonscheduled treatment control group in ambulatory acute, nonbipolar, nonpsychotic depressives. Results show the efficacy of both psychotherapy and amitriptyline in overall symptom reduction. Amitriptyline and psychotherapy were about equal, and the effects of both treatments in combination were additive. The additive effect of combined treatment was largely due to the differential effects of the two treatments. Amitriptyline had its effect mainly on the vegetative symptoms of depression such as sleep and appetite disturbance, these occurred early in treatment, often within the first week. Psychotherapy had its effect mainly on mood, suicidal ideation, work, and interests; these effects occurred slightly later, at four to eight weeks.

Left ventricular radius to wall thickness ratio.

Abstract: Left ventricular relative wall thickness, expressed as the ratio of end-diastolic radius to wall thickness (R/Th ratio), has a constant relation with left ventricular systolic pressure in children and adults with a normal heart, subjects with physiologic forms of cardiac hypertrophy (athletes) and patients with compensated chronic left ventricular volume overload (chronic aortic regurgitation). Greatly increased values for the radius/thickness ratio, suggesting inadequate hypertrophy, indicate a poor prognosis in patients with chronic aortic regurgitation and in those with congestive cardiomyopathy; decreased values for this ratio are found in patients with hypertrophic cardiomyopathy (inappropriate hypertrophy) and in patients with compensated aortic stenosis (appropriate hypertrophy). In patients with compensated aortic stenosis, echocardiographic measurement of the left ventricular end-diastolic radius/wall thickness ratio has been used to estimate left ventricular systolic pressure. Measurement of left ventricular relative wall thickness appears to provide diagnostic and prognostic data in patients with a broad variety of cardiac disorders.

Macroscopic parity violating effects: neutrino fluxes from rotating black holes and in rotating thermal radiation

Abstract: Two macroscopic effects of parity nonconservation are considered. (i) Particle emission by rotating black holes is shown to be asymmetric. In particular, neutrinos are emitted preferentially in the direction opposite to the hole's angular momentum. (ii) It is shown that in a rotating thermal radiation there exist equilibrium neutrino and antineutrino currents parallel to the angular velocity vector.

Cytotoxicity Assay in Antibiotic-Associated Colitis

Abstract: Stools were tested for the presence of a cytopathic toxin that is neutralized by gas gangrene antitoxin or Clostridium sordellii antitoxin. The test was positive in specimens from 51 (96070) of 53 patients with antibiotic-associated pseudomembranous colitis and five (2%) of 248 individuals without gastrointestinal complications of antimicrobial usage. Seven types of tissue cultures were tested, and all proved susceptible to this toxin. Those that appeared to be the most susceptible on the basis of titers of toxin in stools were primary human amnion cells, WI-38 cells, baby hamster kidney cells, and mouse fibroblasts. Storage of specimens at -70 C, 6 C, 28 C, and 37 C for five days before testing resulted in decrease in toxin titers that correlated with increasing temperatures. Studies of various C. sordellii antitoxin preparations indicated considerable variation in potency. Recommendations for performing the tissue culture assay for the toxin found in stools of patients with antibiotic-associated colitis are provided on the basis of these observations. Several recent reports indicate that stools from pa

Semantic facilitation across sensory modalities in the processing of individual words and sentences.

Abstract: The effect of semantic priming upon lexical decisions made for words in isolation (Experiment 1) and during sentence comprehension (Experiment 2) was investigated using a cross-modal lexical decision task. In Experiment 1, subjects made lexical decisions to both auditory and visual stimuli. Processing auditorily presented words facilitated subsequent lexical decisions on semantically related visual words. In Experiment 2, subjects comprehended auditorily presented sentences while simultaneously making lexical decisions for visually presented stimuli. Lexical decisions were facilitated when a visual word appeared immediately following a related word in the sentential material. Lexical decisions were also facilitated when the visual word appeared three syllables following closure of the clause containing the related material. Arguments are made for autonomy of semantic priming during sentence comprehension.

Shift automorphisms in the Hénon mapping

Abstract: We investigate the global behavior of the quadratic diffeomorphism of the plane given byH(x,y)=(1+y−Ax2,Bx). Numerical work by Henon, Curry, and Feit indicate that, for certain values of the parameters, this mapping admits a “strange attractor”. Here we show that, forA small enough, all points in the plane eventually move to infinity under iteration ofH. On the other hand, whenA is large enough, the nonwandering set ofH is topologically conjugate to the shift automorphism on two symbols.

Diffusion–collision model for protein folding

Abstract: The basic equations for the elementary step in the diffusion–collision–coalescence model of protein folding are derived for the case of two radially diffusing spherical microdomains. Refinements and biological implications of the mechanism are considered; included are detailed discussions of the parameters of the model, the possibilities of rotational diffusion and surface diffusion in one or two dimensions, the nature of the microdomains, and the application of the model to protein unfolding.

The Adenylate cyclase-cyclic AMP system in islets of langerhans and its role in the control of insulin release

Abstract: The mechanisms by which glucose and other stimulators control the rate of insulin release from the /3-cells of islets of Langerhans is still far from understood. In general terms, it is assumed that a receptor for a glucose metabolite is the initiator of interactions leading to increased insulin release. These interactions may involve cyclic AMP, Ca ++ , cytosol components, microfilaments and microtubules, the insulin containing granule membranes and the Ncell plasma membrane, and lead to fusion of granule membranes with the plasma membrane and the release of insulin from the cell. This short review concentrates on the adenylate cyclase system including the enzyme, its product cyclic AMP, cyclic nucleotide phosphodiesterases which break down cyclic AMP, effector systems for cyclic AMP such as protein kinases and phosphoprotein phosphatases. Inevitably, the interaction with glucose will be an important theme in the discussion because (a) cyclic AMP \"potentiates\" the insulin-releasing capability of glucose and (b) glucose increases the intracellular concentration of cyclic AMP in islets of Langerhans. Knowledge that cyclic AMP enhances the/3-cell response to glucose came from the demonstration that glucagon increased insulin secretion and that the response to glucagon was greater during hyperglycaemia that at normal glucose levels [1-4]. By analogy with the effect of glucagon in stimulating adenylate cyclase in liver, it was suggested that cyclic AMP was involved in the mediation of these effects. Since that time, many reports have confirmed the effects of glucagon on insulin release, and the similarities of action between those agents which raise intracellular cyclic AMP levels, such as glucagon, /3-adrenergic agents, phosphodiesterase inhibitors (papaverine, methylxanthines) and cholera toxin, and the effects of exogenous cyclic AMP or dibutyryl cyclic AMP have been noted [5-14]. It is clear from these reports that when the cyclic AMP concentration of the/3-cell is raised, by whatever means, the insulin response to glucose stimulation is enhanced. It is also clear that the effects of cyclic AMP are greatest at high glucose concentrations, whereas at low, non-stimulatory glucose concentrations the effects of cyclic AMP are usually small.

Caregiving and infant behavior in day care and in homes.

Abstract: Social interaction and play behavior were compared in community-based day care and at home for 2 matched groups of 18-mo-olds (30 Ss). Adult-infant, infant-peer, and infant-toy interaction were time sampled. More adult-infant play, tactile contact, and reciprocal smiling were found in day care. More

Detection of a mediator derived from endotoxin-stimulated macrohpages that induces the acute phase serum amyloid A response in mice.

Abstract: The mechanism by which LPS stimulates an acute phase serum amyloid A (SAA) response in C3H mice has been studied. A factor (SAA inducer) appears in the blood of C3H/HeN (lipopolysaccharide [LPS]-sensitive) mice approximately 1 h after administration of LPS, which, when passively administered, can induce C3H/HeJ mice to produce SAA although they are resistant to the LPS itself. SAA inducer has been detected in the culture medium of LPS treated C3H/HeN macrophages but not spleen cells. Thus, two stages in the induction of the acute phase SAA response are now recognized: a latent period of 2-3 h during which the SAA concentration remains at baseline values and in which SAA inducer appears, and the period of synthesis of SAA which lasts for approoximately 24 h past induction. It is proposed that a macrophage response to LPS is responsible for production of the serum mediator which induces SAA synthesis.

The Underdevelopment of Development Literature: The Case of Dependency Theory

Abstract: As a vehicle for the growing association of southern nationalists and Marxists, dependency theory is an important part of the history of our times, something much more than a school of academic writing. Whatever the varieties of analysis existing within this school (and there are many), a major historiographie shortcoming is common to most of its literature: having grasped the Hegelian insight that the whole is greater than the sum of its parts, dependencistas exaggerate the point, making the mistake of refusing any autonomy, any specificity to the parts (southern countries) independently of their membership in the whole (the imperialist system established by the North). A better approach to the study of the place of the South in the international system is to emphasize the variety of state structures present there with their different abilities to mobilize forces internally and translate this into international rank. Southern advances are more substantial than many realize; the essay concludes that southerners should pay more attention to the real room for initiative and maneuver they have, but which dependency theory systematically overlooks. Most of the illustrative examples concern India, the Ottoman Empire, and Latin America before World War I.

Colitis Induced by Clostridium difficile

Abstract: Clostridium difficile has been implicated as the major cause of antibiotic-associated pseudomembranous colitis. The current laboratory diagnostic test of choice is a tissue culture assay that demonstrates the presence of a cytopathic toxin neutralized by antitoxin to Clostridium sordellii. This toxin was found in stools from 42 of 43 patients with antibiotic-associated pseudomembranous colitis and in stools from 12 of 78 patients with antibiotic-associated diarrhea. Specimens from patients with gastrointestinal conditions unrelated to administration of antibiotics and those from healthy controls were uniformly negative. Neutralization of toxin by antitoxin to C. sordellii appears to represent antigenic cross-reactivity, since broth cultures of C. difficile also contain a cytopathic toxin neutralized by this antitoxin. Strains of C. difficile are susceptible to vancomycin, and the initial clinical experience with oral administration of this agent shows promising results.

A normal cell protein cross-reactive to the major Abelson murine leukaemia virus gene product

Abstract: Abelson murine leukaemia virus (A-MuLV) is a replication-defective retrovirus capable of rapid in vivo and in vitro transformation of bone marrow lymphoid target cells. A-MuLV was isolated from a steroid treated BALB/c mouse inoculated with the replication competent Moloney-MuLV (M-MuLV)1–4. The A-MuLV genome (5.5 kilobases) retains regions of precise homology to M-MuLV at its 5′ end (1,320 bases) and 3′ end (730 bases). The centre of the A-MuLV genome (3,500 bases) is non-homologous to M-MuLV and presumably represents unique sequences derived from the mouse genome by a recombinational event5. The only known protein encoded by the A-MuLV genome is one of MW 120,000, called P120 (refs 6, 7). About one-quarter of this protein is encoded by the 5′-terminal M-MuL V-related sequences and the rest is encoded by the A-MuLV unique sequences. P120 has been found in all cell lines transformed by the strain of A-MuLV that originally derived from ANN-1 cells2, including transformed non-producer cells. P120 can be translated in vitro using A-MuLV genomic RNA as messenger RNA. P120 is a phosphoprotein but there is no evidence for glycosylation6,8,9. We have used an anti-A-MuLV syngeneic tumour regressor serum with defined specificities to search for cross-reacting normal cellular proteins. We have identified a protein of MW 150,000 (NCP150) in metabolically labelled thymus and other lymphoid organs. NCP150 by absorption and competition analysis is closely related to the unique region of the A-MuLV P120 protein.

Synthesis of IgM by Cells of NZB and SWR Mice and Their Crosses

Abstract: Spontaneous and LPS-induced secretion of IgM by cultured spleen cells of NZB and SWR mice were measured after a 4-hr pulse with 3H-leucine. Similar experiments were done with fetal liver cells of NZB, CBA, BALB/c, and C57BL/6 mice. In short-term (4-hr) cultures there was marked hypersecretion of IgM by NZB cells relative to SWR cells. This abnormality was attributed to two factors: an increased number of IgM-containing cells and an increased secretion of IgM per cell. These two factors segregated as independent phenotypes in the progeny of the crosses. Liver cells from 18- to 19- day NZB fetuses matured into IgM hypersecretors in vitro in the absence of T cells. This phenomenon was uninfluenced by addition of thymocytes to cultured fetal liver cells. By contrast with the foregoing, NZB spleen cells maintained in vitro for 5 days, with or without LPS, made as much IgM during a 4-hr pulse with 3H-leucine as identically treated SWR cells. Con A-induced suppressor cells from NZB spleen cells inhibited LPS-stimulated IgM synthesis normally. There appear to be two populations of B cells in NZB mice: abnormal, spontaneously activated hypersecretors of IgM and cells that respond normally to LPS. The former population seems to arise early in life under the influence of two or three different genetic systems and functions independently of T cells.

Effects of radiation on the human gastrointestinal tract.

Abstract: Radiation therapy directed at the abdomen may damage the digestive tract, the type and extent of injury depending on the dose of the radiation and the radiation sensitivity of the gut. Characteristic early changes are manifest in the mucosa of the gut: for later ulceration, changes in the collagen tissues and particularly in the vascular channels occur. This paper describes and characterizes injuries to the esophagus, stomach, small intestine and colon. It emphasizes the importance of recognizing radiation-induced damage to the gut which may occur early or late after radiation.

Selective transsphenoidal adenomectomy in women with galactorrhea-amenorrhea.

Abstract: Thirty women with prolactin (PRL)-secreting adenomas underwent selective adenomectomy via a transsphenoidal route. All had abnormal sella polytomes or visual fields, amenorrhea with low basal serum gonadotropin levels despite decreased serum estradiol concentrations, and elevated basal serum PRL levels with blunted PRL response to neuroendocrine stimulation tests (thyrotropin-releasing hormone, levodopa, chlorpromazine, and hypoglycemia). Of 17 patients with microadenomas, 14 (82.4%) were cured and three (17.6%) improved. None were unchanged or worse. Three (60%) of five patients with larger, but still intrasellar tumors, had normalization of PRL levels, return of menses, and resolution of galactorrhea. The patients with tumors extending out of the sella did not fare as well. Overall, 21 (70%) were cured, six (20%) improved, two (6.7%) were unchanged, and the condition of one (3.3%) became worse. All preoperative neurologic deficits resolved. Postoperative complications were minimal with no neurologic morbidity. When tumors are small, surgical results are excellent with minimal risk. (JAMA242:158-162, 1979)

Hormones and the lung. I. Thyroid hormones and glucocorticoids in lung development

Abstract: It has been proposed that thyroid hormones may have a role in the regulation of lung development and the maturation of the surfactant system. The purpose of this study was to examine the effects of exogenous thyroxine (T4) on rat lung development and to investigate possible interactions of this hormone with the glucocorticoids, other hormones implicated in the regulation of lung development. A number of different experimental protocols were utilized: T4 was administered to day 17 and 18 rat fetuses from untreated animals as well as from animals which had been adrenalectomized or treated with the 11-β-hydroxylase inhibitor, Metopirone; replacement hydrocortisone was administered to some groups. Sham-operated and untreated animals were included as controls. Animals were sacrificed from days 19-22 (term, day 22-23) of gestation and the fetal lungs were examined. Accelerated lung development was observed in all experimental groups receiving T4. Alveolar epithelial cells were more differentiated in comparison to controls. Glycogen deposits were diminished, cell flattening was more advanced, mitochondria, Golgi complexes and rough endoplasmic reticulum were more prominent, and lamellar bodies, storage sites for pulmonary surfactant, were greatly increased in number. Secretion of lamellar bodies into the alveolar space was also stimulated. The results also indicated that T4 and glucocorticoids act together in the acceleration of lung development. Under conditions of decreased glucocorticoids (Metopirone treatment and adrenalectomy), stimulatory effects of T4 were still evident but less pronounced; hydrocortisone replacement increased the observed stimulation. Maximal acceleration of lung development was observed subsequent to T4 and uncontrolled surgical stress. These results demonstrate that T4 can accelerate rat lung development and that this acceleration is maximal in the presence of glucocorticoids.