Showing papers by "Temple University published in 1972"

Microtubule Formation in vitro in Solutions Containing Low Calcium Concentrations

Abstract: Isolated rat brain tubulin can be repolymerized in vitro in solutions containing adenosine triphosphate or guanosine triphosphate, magnesium ions, and a good calcium chelator. The extreme sensitivity of tubulin to calcium ions explains the failure of previous efforts to obtain polymerization and suggests a possible mechanism for regulation of microtubule polymerization in vivo.

Learning from Las Vegas

Abstract: Manifeste sur les theories architecturales et urbaines, marquant la naissance du postmodernisme en architecture, ayant fait l'objet d'une controverse pendant les vingt annees suivant sa parution. - Initialement publ. dans la revue americaine "The Architectural forum", puis repris en monographie en 1972. 2e ed. revisee en 1977 sous le titre "Learning from Las Vegas : the forgotten symbolism of architectural form"

The synthesis of acidic chromosomal proteins during the cell cycle of HeLa S-3 cells. I. The accelerated accumulation of acidic residual nuclear protein before the initiation of DNA replication.

Abstract: The synthesis and accumulation of acidic proteins in the tightly bound residual nuclear fraction goes on throughout the cell cycle of continuously dividing populations of HeLa S-3 cells; however, during late G1 there is an increased rate of synthesis and accumulation of these proteins which precedes the onset of DNA synthesis. Unlike that of the histones, whose synthesis is tightly coupled to DNA replication, the synthesis of acidic residual nuclear proteins is insensitive to inhibitors of DNA synthesis. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of acidic residual nuclear proteins shows different profiles during the G1, S, and G2 phases of the cell cycle. These results suggest that, in contrast to histones whose synthesis appears to be highly regulated, the acidic residual proteins may have a regulatory function in the control of cell proliferation in continuously dividing mammalian cells.

Time sequence of nuclear pore formation in phytohemagglutinin-stimulated lymphocytes and in hela cells during the cell cycle

Abstract: The time sequence of nuclear pore frequency changes was determined for phytohemagglutinin (PHA)-stimulated human lymphocytes and for HeLa S-3 cells during the cell cycle. The number of nuclear pores/nucleus was calculated from the experimentally determined values of nuclear pores/µ2 and the nuclear surface. In the lymphocyte system the number of pores/nucleus approximately doubles during the 48 hr after PHA stimulation. The increase in pore frequency is biphasic and the first increase seems to be related to an increase in the rate of protein synthesis. The second increase in pores/nucleus appears to be correlated with the onset of DNA synthesis. In the HeLa cell system, we could also observe a biphasic change in pore formation. Nuclear pores are formed at the highest rate during the first hour after mitosis. A second increase in the rate of pore formation corresponds in time with an increase in the rate of nuclear acidic protein synthesis shortly before S phase. The total number of nuclear pores in HeLa cells doubles from ∼2000 in G1 to ∼4000 at the end of the cell cycle. The doubling of the nuclear volume and the number of nuclear pores might be correlated to the doubling of DNA content. Another correspondence with the nuclear pore number in S phase is found in the number of simultaneously replicating replication sites. This number may be fortuitous but leads to the rather speculative possibility that the nuclear pore might be the site of initiation and/or replication of DNA as well as the site of nucleocytoplasmic exchange. That is, the nuclear pore complex may have multiple functions.

Teacher Attitudes Associated with the Integration of Handicapped Children

Abstract: A questionnaire was administered to elementary school regular class teachers to determine the effect of an integrative resource room program on the teachers' attitudes toward handicapped children. The questionnaire was designed to elicit teachers' attitudes toward handicapped children with respect to their integration into the regular program, their potential for academic and social adjustment, the teachers' competencies for teaching the children, and the need for special methods and materials in teaching handicapped children. The experimental group consisted of teachers in schools participating in an integrative resource room program, and the control group consisted of teachers in schools with self contained special classes. The results indicated the resource room program had slight to moderate effects on teachers' attitudes and raised questions concerning the feasibility of integrating educable mentally retarded children into regular classes in schools utilizing the conventional grade organizational pat...

Intelligence and Personality

Abstract: Chalke and Ertl (1965) were the first to report evoked-potential correlates of intelligence They compared the latencies of visually-evoked responses, recorded from bipolar leads placed over the left motor area, in three groups of subjects: 33 students with superior IQ’s; 11 subjects with IQ’s in the “low-average” range; and 4 mental retardates with IQ’s ranging from 50 to 65 Three of the five latencies measured (peaks at 142 to 374 msec) yielded significant differences between the groups; the less intelligent subjects had longer latencies Although their findings are of great interest, they are subject to criticism on several grounds The retardate group was small Age was poorly controlled and sex not stated The averaging technique was somewhat unorthodox, as was lead placement However, Chalke and Ertl noted that the latency measurements obtained with their technique agreed well with those obtained with a digital averager, and they selected their lead placement with the idea of “maximizing the input—output delay and thus to enhance the possibility of actually measuring central processing time”

The psychological reaction of patients to legalized abortion

Abstract: Available research concerning psychological effects of abortion is reviewed, and background and psychological data from patients attending a legalized abortion program in New York State are presented. Patients demographically reflected the community at large, and, consistent with the literature, experienced few psychological difficulties. Scientific and ethical implications are discussed.

Nuclear Proteins And The Cell Cycle

Abstract: Publisher Summary This chapter discusses the biochemistry of the cell cycle in continuously dividing cells and the biochemical events that are described in G0 cells stimulated to proliferate. It also focuses on the proteins of the mammalian nucleus and the role that they may play in the control of cellular proliferation. The cell cycle is defined as the interval between the midpoint of mitosis in the parent cell and the midpoint of the subsequent mitosis in one or both daughter cells. The cell cycle is divided into four phases—namely, (1) G1, the period between completion of mitosis and the onset of DNA synthesis; (2) S, the period during which DNA is replicated; (3) G2, the period between the completion of DNA synthesis and the onset of mitosis; and (4) mitosis, the period during which the chromosomes condense, segregate, and are equally distributed to the two daughter cells. Some of the biochemical events that occur during the G0 to S transition in the isoproterenol-stimulated mouse salivary gland and in serum stimulated WI-38 cells are summarized in the chapter. It demonstrates that in continuously dividing cells, as well as in G0 cells that are stimulated to proliferate, a complex and interdependent series of biochemical events precedes the onset of DNA synthesis and mitosis, and a substantial amount of data supports the hypothesis that gene activation is intimately involved in the process.

State-Dependent Learning Produced by Alcohol and Its Relevance to Alcoholism

Abstract: A behavior learned while an animal is drugged sometimes fails to appear during subsequent nondrug test trials, although it appears reliably whenever the drug is readministered. Conversely, if the same behavior is learned when the animal is not drugged, it may then be performed only as long as the animal remains undrugged. For some reason, the ability to perform appears to be conditional upon the drug conditions present during initial acquisition (Overton, 1964). Experimental workers generally refer to this surprising phenomenon as “dissociated” learning or as “state dependent” learning. Clinically trained readers may find it convenient to think of the drug as inducing a sort of temporary “fugue” state separated from the nondrug state by a partial or complete amnesic barrier.

Ultrastructural contributions to the identification of cell types in the lizard epidermal generation.

Abstract: The ultrastructure of the epidermis at different stages of the shedding cycle has been studied in Anolis carolinensis. Cells of the germinal layer are morphologically similar at all stages in the cycle. Immediately after leaving the germinal layer all daughter cells resemble one another closely. However, they later acquire specific ultrastructural features that enable them to be classified into six distinct fully differentiated types corresponding to the grouping previously set forth by light microscopy. A comparison of cytoplasmic filament size with the known X-ray diffraction data suggests that the Oberhautchen and β-layer contain a protein similar to that of avian feather; the protein in the α-layer and lacunar tissue is similar to that in mammalian hair, and the mesos layer cells probably contain a mixture of feather and hair-like proteins. The nature of the amorphous cytoplasmic material in the mature clear layer is as yet unknown.

Carcinoembryonic Antigen Present in Human Colonic Neoplasms Serially Propagated in Hamsters

Abstract: Carcinoembryonic antigen, as measured by radioimmunoassay, is present in two different human colonic tumors that have been serially transplanted and maintained in the cheek pouches of unconditioned, adult golden hamsters. This finding shows that a human tumor-associated antigen can be produced in an animal host.

Hypothalamic norepinephrine: circadian rhythms and the control of feeding behavior.

Abstract: The time of day is a decisive determinant of the effects of l-norepinephrine on feeding behavior. During the dark, direct application of l-norepinephrine to the hypothalamus of rats suppressed feeding behavior. During the light, treatment with the same dose of l-norepinephrine facilitated feeding behavior. Thus, l-norepinephrine has dual and opposite effects on feeding behavior. A hypothalamic substrate that fluctuates in a circadian rhythm could account for both actions of l-norepinephrine.

The initial synthesis of proteins during development. Phosphoenolpyruvate carboxylase in rat liver at birth.

Abstract: 1. A specific antibody, prepared by immunizing rabbits with phosphoenolpyruvate carboxylase (EC 4.1.1.32) purified from adult rat liver, was used to study the appearance of this enzyme in livers from developing rats. 2. Although some inactive precursor of the enzyme may be present in foetal liver, the amount is not sufficient to account for the enzyme appearance at birth. 3. The rate of phosphoenolpyruvate carboxylase synthesis relative to other cytosol proteins increases 20-fold from the foetus to the 1-day-old rat. The high rate of synthesis was maintained at least until 3 days after birth. 4. There was no measurable degradation of phosphoenolpyruvate carboxylase during the first day after birth. During this period the hepatic enzyme content increased 12-fold. 5. When phosphoenolpyruvate carboxylase attained a constant activity in the liver of rats 2 days after birth the half-time of degradation was approx. 13h. 6. We suggest that the pattern of changes occurring during appearance of phosphoenolpyruvate carboxylase is similar to substrate-induced enzyme induction in bacteria.

Secretory mechanisms. Behaviour of adenine nucleotides during the platelet release reaction induced by adenosine diphosphate and adrenaline.

Abstract: 1 Platelets containing adenine nucleotides labelled with (3)H and (14)C in vitro were aggregated biphasically with ADP and adrenaline Amounts of ATP and ADP as well as the radioactivity of ATP, ADP, AMP, IMP, hypoxanthine and adenine were determined in platelets and plasma at different stages of aggregation 2 ATP and ADP were released during the second aggregation phase and had a low specific radioactivity compared with the ATP and ADP retained by the cells The specific radioactivity of intracellular nucleotides increased during release The parameters observed with ADP and adrenaline as release inducers were the same as for collagen and thrombin 3 Release induced by all four inducers was accompanied by conversion of cellular [(3)H]ATP into extracellular [(3)H]-hypoxanthine By variation of temperature, inducer concentration, time after blood withdrawal and use of acetylsalicylic acid, the aggregation pattern caused by adrenaline and ADP could be made mono- or bi-phasic Release or second-phase aggregation was intimately connected with the ATP-hypoxanthine conversion, whereas first phase aggregation was not 4 The [(3)H]ATP-hypoxanthine conversion started immediately after ADP addition With adrenaline it usually started with the appearance of the second aggregation phase The conversion was present during first phase of ADP-induced aggregation only if a second phase were to follow 5 When secondary aggregation took place while radioactive adenine was being taken up by the platelets, increased formation of labelled hypoxanthine still occurred, but there was either no change or an increase in the concentration of labelled ATP 6 Biphasically aggregated platelets converted [(3)H]adenine more rapidly into [(3)H]-ATP and -hypoxanthine than non-aggregated platelets Addition of [(3)H]adenine at different stages of biphasic aggregation showed that more [(3)H]hypoxanthine was formed during than after the release step 7 We conclude that ADP and adrenaline, like thrombin and collagen, cause extrusion of non-metabolic granula-located platelet adenine nucleotides During release metabolic ATP breaks down to hypoxanthine, and this process might reflect an ATP-requiring part of the release reaction

THE SYNTHESIS OF ACIDIC CHROMOSOMAL PROTEINS DURING THE CELL CYCLE OF HELA S-3 CELLS : II. The Kinetics of Residual Protein Synthesis and Transport

Abstract: The kinetics of acidic residual chromosomal protein synthesis and transport were studied throughout the cell cycle in HeLa S-3 cells synchronized by 2 mM thymidine block and selective detachment of mitotic cells. Pulse labeling the cells with leucine-3H for 2 min and then "chasing" the radioactive proteins for up to 3 hr showed that the amount of protein synthesized, transported, and retained in the acidic residual chromosomal protein fraction is greater immediately after mitosis and later in G1 than in the S or G2 phases of the cell cycle. During S, only 20–25% of the proteins synthesized and transported to the acidic residual chromosomal protein fraction are chased during the first 2 hr after pulse labeling, whereas up to 40% of the material entering the residual nuclear fraction in mitosis, G1, and G2 leaves during a 2 hr chase. Polyacrylamide gel electrophoretic profiles of these proteins, at various times after pulse labeling, reveal that the turnover of individual polypeptides within this fraction has kinetics of synthesis and turnover which are markedly different from one another and undergo stage-specific changes.