STUDIES ON MOUSE LEUKEMIA : VII. THE RELATION OF CELL DEATH TO THE POTENCY OF INOCULATED CELL SUSPENSIONS

The effect of heat, hypo- and hypertonic salt solutions, glycerin, desiccation, and mechanical injury was studied on leukemic lymphoid cells of the mouse, and the leukemia-transmitting property of cell suspensions (hypothetical transmitting agent) in vitro. The results indicate that leukemia has not been transmitted by inoculation without the introduction of living cells. The interval between inoculation and death bears an inverse relationship to the number of living cells inoculated

STUDIES ON MOUSE LEUKEMIA : III. A COMPARISON OF FOUR LINES OF LEUKEMIA TRANSMITTED BY INOCULATION

Several lines of lymphatic leukemia in mice, experimentally transmitted by inoculation into hosts of a closely inbred strain, have been established and carried on simultaneously. Among the inoculated mice there were found different types of response, according to the line of leukemia inoculated. The differences consisted mainly in the extent or distribution of lesions. Although the same line did not always show the same distribution of lesions, there was a distinct tendency for the cases in a line to present the same characteristics on successive transfers over a considerable period. A comparison of the frequency of the occurrence of certain lesions in four lines of transmission shows that: 1. Increases in the total leucocyte counts were less common and less marked in Lines A and E than in Lines H and I. In the lines first mentioned, normal counts were relatively frequent. In Line H normal counts were uncommon, and in Line I were not observed. The highest counts were found in Line I. 2. Peritoneal effusion was characteristic of Line A for 43 transfers. It was found in Line E, but for a considerably shorter period and in a smaller proportion of cases; it was rare in Lines H and I. 3. Pleural effusion was frequently found in Lines A and E but rarely in Lines H and I. 4. Infiltration in the liver occurred to a marked degree in all the mice of Lines H and I, but in fewer mice and to a variable degree in Lines A and E. 5. Infiltration in the kidney in Line I was present in 90 per cent of the mice, and was of marked grade. In line H it was present in 67 per cent of the mice (24 per cent of marked grade) but in Lines A and E it was rare. 6. A considerable amount of variability in results occurred in Lines A and E, whereas Lines H and I remained remarkably constant. The lesions characteristic of a line were not necessarily those present in the spontaneous case from which the first transfer of the line was made. As the mice used for inoculation were genetically uniform, the differences between the lines are not due to genetic differences in the hosts, but to differences in the materials inoculated

STUDIES ON LEUKEMIA IN MICE : I. THE EXPERIMENTAL TRANSMISSION OF LEUKEMIA

Lymphatic leukemia has occurred with great frequency in a particular strain of mice which have been inbred by brother-sister matings since 1921. In addition to typical cases of leukemia are others which, because of the absence of leukemic changes in the blood, correspond to "pseudoleukemia" and others which, by the presence of unusually great enlargement of certain lymph node groups resemble the "leukosarcomatoses" as observed in man. Examinations of the blood of leukemic mice have shown that leukemic blood pictures are not necessarily early in their appearance, nor are they constant. The blood picture may not, therefore, be used as a criterion for the separation of the two diseases (leukemia and pseudoleukemia) but merely indicates different phases of the same condition. Likewise, cases with lesions intermediate between the local growths of "leukosarcomatosis" and the more general lymphatic enlargements of leukemia suggest that these conditions differ only in the distribution of lesions but not in their nature. Lymphatic leukemia occurring spontaneously in this strain may be transmitted to other mice of the same strain, and carried, apparently, for an unlimited number of transfers in animals at an earlier age than that at which leukemia occurs spontaneously. In each of 10 such experiments transmissions were obtained. The lesions produced by inoculation correspond to those of spontaneous cases, in that they consist of growths of abnormal lymphoid cells which infiltrate tissues and organs and often appear in the circulating blood. Only minor differences have occurred, some of which are characteristic of certain experimental lines. After repeated transfers, the disease tends to run a more acute course. Among the cases in which transmissions occurred, are some without leukemic changes in the blood, and many with local growths at the site of inoculation or in certain node groups. The differences in the blood pictures and distribution of lesions (which latter may be influenced to some extent by the method of inoculation) correspond to similar differences which are sometimes observed in the spontaneous cases

Connect Me! Antecedents and Impact of Social Connectedness in Enterprise Social Software

Companies are increasingly adopting social software to support collaboration and networking. Although increasing their employees’ connectedness is a major driver for organizations to deploy enterprise social software (ESS), the social connectedness concept itself is still not sufficiently defined and conceptualized. The study therefore provides a richer perspective on social connectedness’s role in an ESS context. The authors thus investigate (1) social connectedness’s antecedents and (2) its impact on employees’ individual performance. With a survey-based investigation among 174 employees of an international business software provider headquartered in Germany, the authors show that both reputation and a critical mass significantly influence employees’ social connectedness. The authors further find that reputation’s effect is significantly stronger than critical mass’s effect and that social connectedness influences employees’ individual performance positively. The findings are discussed in the light of psychological studies and deduce implications for theory and practice

Understanding young people's transitions in university halls through space and time

This article contributes to the theoretical discussion about young people's transitions through space and time. Space and time are complex overarching concepts that have creative potential in deepening understanding of transition. The focus of this research is young people's experiences of communal living in university halls. It is argued that particular space-time concepts draw attention to different facets of experience and in combination deepen the understanding of young people's individual and collective transitions. The focus of the article is the uses of the space-time concepts 'routine', 'representation', 'rhythm' and 'ritual' to research young people's experiences. The article draws on research findings from two studies in the North of England. © 2010 SAGE Publications

Ursinus College Alumni Journal, March 1965

Contributors • From the President • Chemathphy: The integrated science course • The changing face of history • Kirkridge • Candidates • Bargains in life income contracts and annuities with Ursinus College • Mid-year report of 1965 Loyalty Fund campaign • Alumni are nearing capital funds goal • Seeds of hope in Latin America • Campus clippings: Financial support; Soph at age 49; Women\u27s Club; On the air; TW3 was there; Devotions booklet; On treasurer\u27s staff; New reserve book room; The international tone; Bus link; ACLU board member; Farewell & welcome • Track prospects for 1965 • Indoor track • Cross country • Soccer success • New coaches • Wrestling • Alumnae hockey stars • Undefeated in hockey • Football finale • Husband and wife lead small-town church to union • Advertising executive sets fast pace in Baltimore • Class notebook • Weddings • Births • In memoriam • Regionals • At your service • End quotes: The alumnus as patron of learninghttps://digitalcommons.ursinus.edu/alumnijournal/1082/thumbnail.jp

Nuclear Shell Model Calculations of Neutralino-Nucleus Cross Sections for Silicon 29 and Germanium 73

We present the results of detailed nuclear shell model calculations of the spin-dependent elastic cross section for neutralinos scattering from \si29 and \ge73. The calculations were performed in large model spaces which adequately describe the configuration mixing in these two nuclei. As tests of the computed nuclear wave functions, we have calculated several nuclear observables and compared them with the measured values and found good agreement. In the limit of zero momentum transfer, we find scattering matrix elements in agreement with previous estimates for \si29 but significantly different than previous work for \ge73. A modest quenching, in accord with shell model studies of other heavy nuclei, has been included to bring agreement between the measured and calculated values of the magnetic moment for \ge73. Even with this quenching, the calculated scattering rate is roughly a factor of 2 higher than the best previous estimates; without quenching, the rate is a factor of 4 higher. This implies a higher sensitivity for germanium dark matter detectors. We also investigate the role of finite momentum transfer upon the scattering response for both nuclei and find that this can significantly change the expected rates. We close with a brief discussion of the effects of some of the non-nuclear uncertainties upon the matrix elements.Comment: 31 pages, figures avaiable on request, UCRL-JC-11408

Cyclic Nucleotide Phosphodiesterases and Compartmentation in Normal and Diseased Heart

International audienceCyclic nucleotide phosphodiesterases (PDEs) degrade the second messengers cAMP and cGMP, thereby regulating multiple aspects of cardiac function. This highly diverse class of enzymes encoded by 21 genes encompasses 11 families which are not only responsible for the termination of cyclic nucleotide signalling, but are also involved in the generation of dynamic microdomains of cAMP and cGMP controlling specific cell functions in response to various neurohormonal stimuli. In myocardium, the PDE3 and PDE4 families are predominant to degrade cAMP and thereby regulate cardiac excitation-contraction coupling. PDE3 inhibitors are positive inotropes and vasodilators in human, but their use is limited to acute heart failure and intermittent claudication. PDE5 is particularly important to degrade cGMP in vascular smooth muscle, and PDE5 inhibitors are used to treat erectile dysfunction and pulmonary hypertension. However, these drugs do not seem efficient in heart failure with preserved ejection fraction. There is experimental evidence that these PDEs as well as other PDE families including PDE1, PDE2 and PDE9 may play important roles in cardiac diseases such as hypertrophy and heart failure. After a brief presentation of the cyclic nucleotide pathways in cardiac cells and the major characteristics of the PDE superfamily, this chapter will present their role in cyclic nucleotide compartmentation and the current use of PDE inhibitors in cardiac diseases together with the recent research progresses that could lead to a better exploitation of the therapeutic potential of these enzymes in the future

A Biphasic and Brain-Region Selective Down-Regulation of Cyclic Adenosine Monophosphate Concentrations Supports Object Recognition in the Rat

Background: We aimed to further understand the relationship between cAMP concentration and mnesic performance. Methods and Findings: Rats were injected with milrinone (PDE3 inhibitor, 0.3 mg/kg, i.p.), rolipram (PDE4 inhibitor, 0.3 mg/ kg, i.p.) and/or the selective 5-HT4R agonist RS 67333 (1 mg/kg, i.p.) before testing in the object recognition paradigm. Cyclic AMP concentrations were measured in brain structures linked to episodic-like memory (i.e. hippocampus, prefrontal and perirhinal cortices) before or after either the sample or the testing phase. Except in the hippocampus of rolipram treated-rats, all treatment increased cAMP levels in each brain sub-region studied before the sample phase. After the sample phase, cAMP levels were significantly increased in hippocampus (1.8 fold), prefrontal (1.3 fold) and perirhinal (1.3 fold) cortices from controls rat while decreased in prefrontal cortex (,0.83 to 0.62 fold) from drug-treated rats (except for milrinone+RS 67333 treatment). After the testing phase, cAMP concentrations were still increased in both the hippocampus (2.76 fold) and the perirhinal cortex (2.1 fold) from controls animals. Minor increase were reported in hippocampus and perirhinal cortex from both rolipram (respectively, 1.44 fold and 1.70 fold) and milrinone (respectively 1.46 fold and 1.56 fold)-treated rat. Following the paradigm, cAMP levels were significantly lower in the hippocampus, prefrontal and perirhinal cortices from drug-treated rat when compared to controls animals, however, only drug-treated rats spent longer time exploring the novel object during the testing phase (inter-phase interval of 4 h)