Showing papers by "University of Pennsylvania published in 1970"

EBV DNA in biopsies of Burkitt tumours and anaplastic carcinomas of the nasopharynx.

Abstract: Epstein–Barr Virus in Burkitt's Lymphoma and Nasopharyngeal Carcinoma: EBV DNA in Biopsies of Burkitt Tumours and Anaplastic Carcinomas of the Nasopharynx

Cell Communication, Calcium Ion, and Cyclic Adenosine Monophosphate

Abstract: The hypothesis advanced in this article requires further validation. Undoubtedly it will require modification as our knowledge of biochemical control increases. Nevertheless, it should prove useful in focusing attention on the apparent similarity in the response of a large number of specific cell types to particular stimuli. Emphasis has been placed on a few common and apparently key elements in these responses. It is recognized that other factors are undoubtedly involved. Specifically, the changes in membrane potentials indicate the likelihood of widespread changes in the properties of the cell membrane, for example, changes in Na(+) and K(+) transport and distribution. These aspects of cellular responses may eventually prove to be of equal or greater importance than those common aspects of the system already identified.

The study of language in its social context

Abstract: The work which is reported in this study is an investigation of language within the social context of the community in which it is spoken It is a study of a linguistic structure which is unusually complex, but no more so than the social structure of the city in which it functionsWithin the linguistic structure, change has occurred on a large scale, and at a rapid pace which is even more characteristic of the changing structure of the city itself Variability is an integral part of the linguistic system, and no less a part of the behavior of the city To assess the relative complexity of the linguistic problem presented by New York City, it may be useful to compare this investigation to an earlier study of a sound change in progress that I carried out on the island of Martha's Vineyard (Labov 1963) This earlier work traced the distribution of a particular sound feature as it varied through several occupational, ethnic, and geographic sub-groups of the population, and through three generations of native islanders The objective pattern of language behavior was seen to be correlated with the overall social pattern of differential reaction to specific economic strains and social pressures; it was then possible to assign a single social meaning to the linguistic feature in question It was thus demonstrated that social pressures are continually acting upon the structure of a language, as it develops through the mechanism of imitation and hypercorrection

Estimating the Reliability, Systematic Error and Random Error of Interval Data

Abstract: IN content analysis as in all situations in which unstructured observations play an important role, the reliability with which data are generated is of crucial importance. Low data reliability limits the confidence in the validity of subsequent inferences and the reliability of a population of data must be estimated from the agreement among many observers regarding a sample. The way reliability of data is assessed is not different in principle from the way the reliability of psychological tests is measured. However, in the process of developing recording instructions, defining units of analysis and operationalizing scales, the researcher requires more detailed information about the sources and kind of unreliability. Over-all measures of agreement do not provide such information readily. More specifically, the analyst of a recording instrument may wish to obtain:

A Concept Of Corporate Planning

Abstract: In this article, Professor Ackoff develops a new concept of planning, Adaptive Planning—in a systematic way and attempts to exploit the management and behavioural sciences to the fullest. He discusses the nature of planning, the parts of the planning system, and the different philosophies of planning—which he calls satisficing, optimizing, and adaptivizing. He concludes that “at the present time satisficing planning is the only one of the three approaches to which we can normally adhere completely.”

On the magnetic field generated outside an inhomogeneous volume conductor by internal current sources

Abstract: The magnetocardiogram results from the detection of magnetic fields generated outside the body by electric current sources in the heart. Let the source current dipole moment per unit volume be Ji, the conductivity g , the electric potential V , and the electric field intensity E . Then it may be shown that the magnetic field H is given by either H = (1/4\pi) \int J^{i} \times abla(1/r) dv + \sum_{i} \int (g' - g")(E \times dS_{i}/r) , or H = (1/4\pi) \int J^{i} \times abla(1/r) dv + \sum_{i} \int (g' - g")V abla(1/r) \times dS_{i} , where the surface integral is over all surfaces S i separating regions of different conductivity, i.e., g ' and g ", and r is the distance from the point of measurement to the element of volume or surface. The magnetic dipole moment m is given by m = \frac{1}{2} \int r_{1} \times J^{i}dv - \frac{1}{2} \sum_{i} \int (g'-g")Vr_{1} \times dS_{i} , where r 1 is a radius vector from an arbitrary origin.

Free States of the Canonical Anticommutation Relations

Abstract: Each gauge invariant generalized free state ω A of the anticommutation relation algebra over a complex Hilbert spaceK is characterized by an operatorA onK. It is shown that the cyclic representations induced by two gauge invariant generalized free states ω A and ω B are quasi-equivalent if and only if the operatorsA 1/2−B 1/2 and (I−A)1/2−(I−B)1/2 are of Hilbert-Schmidt class. The combination of this result with results from the theory of isomorphisms of von Neumann algebras yield necessary and sufficient conditions for the unitary equivalence of the cyclic representations induced by gauge invariant generalized free states.

Inhibition of myoblast fusion after one round of dna synthesis in 5-bromodeoxyuridine

Abstract: The thymidine analogue 5-bromodeoxyuridine (BUdR) has a differential effect on the synthesis of tissue-specific products and molecules required for growth and division. Proliferating myogenic cells cultured in BUdR fail to fuse and fail to initiate the synthesis of contractile protein filaments. Conversely, BUdR has but a minor effect on cell viability and reproductive integrity. Low concentrations of BUdR result in an enhancement of cell number relative to the controls; higher concentrations are cytotoxic. Suppression of myogenesis is reversible after at least 10 cell generations of growth in the analogue. Cells that do not synthesize DNA, such as postmitotic myoblasts and myotubes, are not affected by BUdR. Incorporation of BUdR for one round of DNA synthesis was accomplished by first incubating myogenic cells, prior to fusion, in 5-fluorodeoxyuridine (FUdR) to block DNA synthesis and collect cells in the presynthetic phase. The cells were then allowed to synthesize either normal DNA or BU-DNA for one S period by circumventing the FUdR block with BUdR or BUdR plus thymidine (TdR). The cultures were continued in FUdR to prevent dilution of the incorporated analogue by further division. After 3 days, the cultures from the FUdR-BUdR series showed the typical BUdR effect; the cells were excessively flattened and few multinucleated myotubes formed. Cells in the control cultures were of normal morphology, and multinucleated myotubes were present. These results were confirmed in another experiment in which BUdR-3H was added to 2-day cultures in which myotubes were forming. Fusion of thymidine-3H-labeled cells begins at 8 hr after the preceding S phase. In contrast, cells which incorporate BUdR-3H for one S period do not fuse with normal myotubes.

The increasing incidence of central nervous system leukemia in children. (Children's cancer study group a)

Abstract: The incidence of symptomatic CNS leukemia was studied in 209 children, all of whom were entered in a cooperative study during 1963-1964, and received the same chemotherapeutic agents. The overall incidence was 51%, and the median time for occurrence of the first episode was 9 months. The incidence was 56% in patients with acute lymphocytic leukemia (A. L. L.) and 25% in those with other forms of leukemia. CNS symptoms developed at a steady monthly rate of 3.8% for the first 24 months and then decreased to 2%. The rate for the first year was the same for all forms of leukemia; it was 4% in A. L. L. and 3.7% in the other forms combined. The overall median survival was 18 months—it was 21 months for patients with A. L. L. and 9 months for the other cell types. Life-table analysis showed a median survival of 8 months for patients who had developed CNS leukemia and 24 months for those free of the complication. Age, sex, hematologic status, and chemotherapy regimen did not influence the incidence. We conclude that the increasing survival of children with leukemia is the chief cause for the increased incidence of CNS leukemia noted by many investigators.

Distributional Structure

Abstract: For the purposes of the present discussion, the term structure will be used in the following non-rigorous sense: A set of phonemes or a set of data is structured in respect to some feature, to the extent that we can form in terms of that feature some organized system of statements which describes the members of the set and their interrelations (at least up to some limit of complexity). In this sense, language can be structured in respect to various independent features. And whether it is structured (to more than a trivial extent) in respect to, say, regular historical change, social intercourse, meaning, or distribution - or to what extent it is structured in any of these respects - is a matter decidable by investigation. Here we will discuss how each language can be described in terms of a distributional structure, i.e. in terms of the occurrence of parts (ultimately sounds) relative to other parts, and how this description is complete without intrusion of other features such as history or meaning. It goes without saying that other studies of language - historical, psychological, etc.-are also possible, both in relation to distributional structure and independently of it.

Rating Scales and Information Recovery—How Many Scales and Response Categories to Use?:

Abstract: Managers and researchers concerned with marketing and attitudinal research frequently encounter the problem of determining the number of rating scales to use and the number of response categories t...

In Vitro Development of Mouse Oocytes

Abstract: Several aspects of the early in vitro development of the laboratory mouse were examined: oocyte nuclear maturation, fertilization, fertilization of oocytes matured in vitro, and fetal development of oocytes matured and fertilized ii, vitro. Initially, optimum conditions for both oocyte nuclear maturation and fertilization were established. Oocyte nuclear maturation was greatest (91.7%) when oocytes were cultured with cumulus cells. The reduction in maturation when oocytes were cultured without cumulus cells (to 59.2%) was significant (p < 0.02) only when serum was not present in the medium. Fertilization i,i vitro of oviducal oocytes, measured by the number of two-cell ova formed, was greatest (90.1%) when the medium contained 30 mg/ml protein and the oocytes were fertilized with adhering cumulus cells. The removal of the cumulus cells from the oocytes prior to fertilization reduced (p < 0.001) the number of two-cell ova formed (90.1% to 46.3%). Using the optimum conditions which produced 91.7% nuclear maturation and 90.1% fertilization, 37.5% of oocytes matured in vitro were fertilized In vitro. When serum was omitted from the maturation medium a significant drop (p < 0.01) to 22.5% fertilization occurred. When oocytes matured and fertilizedin vitro were transferred into foster mothers, 3.2% developed into 15-day-old fetuses, thus demonstrating that normal oocyte maturation processes can occur in vitro.

Empirical Evidence on the Formation of Price Expectations

Abstract: This article investigates empirical evidence on the structure of price expectations in the United States during the post-Korean War period. The study utilizes semiannual data which describe price expectations for six months and twelve months ahead. The objective is to use these two sets of data to test some of the well-known expectational hypotheses. Incidental to this we determine whether expectations satisfy the rationality hypothesis, and we briefly consider the accuracy of the predictions.

Induction of Intestinal Brush Border Alkaline Phosphatase by Vitamin D and Identity with Ca-ATPase

Abstract: VITAMIN D may increase the rate of intestinal transport of calcium through a primary action on nucleic acid and protein synthesis1,2. Wasserman and Taylor have detected a calcium binding protein in chick intestine which is induced by vitamin D3. Harmeyer and DeLuca, however, reported a discrepancy between the time course of change in calcium transport and of the increase in calcium binding protein4. In addition, calcium binding protein appears in the soluble portion of the cell3, whereas the major site of vitamin D action may be at the level of microvillar membrane5,6. Thus, a comparison of isolated intestinal microvilli from vitamin D deficient and repleted animals might reveal other specific alterations which could be related to the action of vitamin D.

Mitochondrial responses to carbon monoxide toxicity

Abstract: CO not only bonds hematin iron in blood hemoglobin but also ligands hematin iron atoms of cytochrome a/sub 3/. Nonuniform distribution of CO means that rapidly metabolizing tissue are more susceptible to CO toxicity. Mitochondria are protected by branching and cushioning mechanism so CO toxicity response is not linear as in COHb formation. O/sub 2/ flux in respiratory change is not altered by CO. In these in vitro experiments, as little as 100 ppM CO transiently disrupted cytochrome system in transition from anoxia to nonmoxia, slowing the oxidaton of the chain. Pigeon mitochondria were extremely sensitive to CO when in metabolically-active (uncoupled) state. Increased binding of CO to cytochrome a/sub 3/ during anoxia was observed.

Requirement of Adenosine 3′, 5′-Cyclic Phosphate for Flagella Formation in Escherichia coli and Salmonella typhimurium

Abstract: Adenosine-3′,5′-cyclic phosphate (cyclic AMP) is absolutely required for flagella formation and, hence, motility in cyclic AMP-deficient mutants of Escherichia coli and Salmonella typhimurium.

The Intracellular Site of Calcium Activation of Contraction in Frog Skeletal Muscle

Abstract: Radioautography has been used to localize 45Ca in isotopically labeled frog skeletal muscle fibers which had been quickly frozen during a maintained tetanus, a declining tetanus, or during the period immediately following a tetanus or a contracture. During a tetanus almost all of the myofibrillar 45Ca is localized in the region of the sarcomere occupied by the thin filaments. The amount varies with the tension being developed by the muscle. The movement of calcium within the reticulum from the tubular portion to the terminal cisternae during the posttetanic period has a half-time of about 9 sec at room temperature and a Q10 of about 1.7. Repolarization is not necessary for this movement. Evidence is given to support the notion that most calcium efflux from the cell occurs from the terminal cisternae into the transverse tubules.

Quantitative studies on the mixed lymphocyte interaction in rats iv. immunologic potentiality of the responding cells

Abstract: Studies were designed to provide some explanation for the unexpectedly large proportion (2%) of parental rat strain peripheral blood lymphocytes that are reactive in the mixed lymphocyte interaction (MLI) to a strong homologous transplantation isoantigen(s) present on cells from an F(1) donor. The possibilities considered involve nonspecific activation and multispecific reactivity on the part of the responding cells. The essential findings of this study were: (a) In 3-way mixed cultures, lymphocytes obtained from tolerant animals were not "recruited" to proliferate in the presence of cells from normal, isologous donors which were in the process of responding to F(1) cells bearing the tolerance-inducing antigens. With the use of chromosome markers and normal and tolerant parental strain donors of different sexes, the responsive cells were identified and proved to be derived from the normal and not the tolerant donor. (b) The magnitude of the proliferative response is increased additively when potentially reactive cells are exposed to two antigen systems simultaneously. On the other hand, doubling the "gene-dosage" of the genetic determinants of the H isoantigens employed had no effect on the responding cells. (c) A state of induced immunologic tolerance to one H isoantigen system did not alter the response capacity of cells from such a donor to an alternative antigen system. (d) Mixed cultures of heterologous cells from human and rat donors displayed a proliferative response which was less than that of homologous mixed cultures from human or rat donors. Prior sensitization of rat donors with human cells, however, greatly increased the mitotic activity of rat lymphocytes stimulated with human cells. These results suggest that the large number of responsive cells in the MLI do not include a significant number recruited or activated in some nonspecific manner. Rather, they appear to be fully specific in their response capacities so that a given lymphocyte does not react to a multiplicity of different antigens. The degree of proliferation depends on the number of different antigen systems presented to the responding population and not on the number of genetic determinants or "gene dosage" of a given isoantigen system. Finally, on a cell-for-cell basis, the peripheral blood lymphocyte population contains more cells reactive to histocompatibility isoantigens within the species than to heterologous antigens of a different species.