Heterodimerization of AML1/ETO with CBFβ is required for leukemogenesis but not for myeloproliferation

The AML1/Runx1 transcription factor and its heterodimerization partner CBFβ are essential regulators of myeloid differentiation. The chromosomal translocation t(8;21), fusing the DNA binding domain of AML1 to the corepressor eight-twenty-one (ETO), is frequently associated with acute myeloid leukemia and generates the AML1/ETO (AE) fusion protein. AE represses target genes usually activated by AML1 and also affects the endogenous repressive function of ETO at Notch target genes. In order to analyze the contribution of CBFβ in AE-mediated leukemogenesis and deregulation of Notch target genes, we introduced two point mutations in a leukemia-initiating version of AE in mice, called AE9a, that disrupt the AML1/CBFβ interaction (AE9aNT). We report that the AE9a/CBFβ interaction is not required for the AE9a-mediated aberrant expression of AML1 target genes, while upregulation/derepression of Notch target genes does require the interaction with CBFβ. Using retroviral transduction to express AE9a in murine adult bone marrow-derived hematopoietic progenitors, we observed that both AE9a and AE9aNT lead to increased myeloproliferation in vivo. However, both development of leukemia and long-term replating capacity are only observed with AE9a but not with AE9aNT. Thus, deregulation of both AML1 and Notch target genes is required for the development of AE9a-driven leukemia.

One-Year stable perovskite solar cells by 2D/3D interface engineering

Despite the impressive photovoltaic performances with power conversion efficiency beyond 22%, perovskite solar cells are poorly stable under operation, failing by far the market requirements. Various technological approaches have been proposed to overcome the instability problem, which, while delivering appreciable incremental improvements, are still far from a market-proof solution. Here we show one-year stable perovskite devices by engineering an ultra-stable 2D/3D (HOOC(CH₂)₄NH₃)₂PbI₄/CH₃NH₃PbI₃ perovskite junction. The 2D/3D forms an exceptional gradually-organized multi-dimensional interface that yields up to 12.9% efficiency in a carbon-based architecture, and 14.6% in standard mesoporous solar cells. To demonstrate the up-scale potential of our technology, we fabricate 10 × 10 cm² solar modules by a fully printable industrial-scale process, delivering 11.2% efficiency stable for >10,000 h with zero loss in performances measured under controlled standard conditions. This innovative stable and low-cost architecture will enable the timely commercialization of perovskite solar cells.

Up-scaling represents a key challenge for photovoltaics based on metal halide perovskites. Using a composite of 2D and 3D perovskites in combination with a printable carbon black/graphite counter electrode; Grancini et al., report 11.2% efficient modules stable over 10,000 hours.

Über die Bestimmung der optischen Konstanten von Halbleitern des Typus AIII BV im Infraroten

An einer Reihe von halbleitenden Verbindungen der Elemente der 3. und 5. Gruppe des periodischen Systems werden durch Reflexions- und Durchlässigkeitsmessungen im Infraroten (0,8 bis 15,2 μ) die Absorptionskonstante und der Brechungsindex, sowie die Breite der verbotenen Zone bestimmt.

Optische Bestimmung der Temperaturabhängigkeit des Bandabstandes von Halbleitern des Typus AIIIBV

Durch Messungen der Lage der Absorptionskante von Halbleitern bei verschiedenen Temperaturen läßt sich die Temperaturfunktion des Bandabstandes ΔE bestimmen. Vorliegende Untersuchungen an einigen Halbleitern des Typus AIIIBv ergaben im Temperaturbereich 100° K < T < 500° K für ΔE (in eV) folgende Werte:

Optische Untersuchungen an der halbleitenden Mischkristallreihe In (Asy P1-y)

Aus Durchlässigkeits- und Reflexionsmessungen im Spektralbereich von 1 bis 35 μ an n-leitenden Proben des Mischkristallsystems In (Asy P1-y) werden die Absorptionskonstanten und Brechungsindizes bestimmt und graphisch dargestellt.

Für den Bandabstand ΔΕ (in eV) ergibt sich eine lineare Abhängigkeit sowohl vom Arsengehalt y (in Atomanteilen) als auch von der Temperatur T (in°K)

ΔΕ = 1,42 -0,98 y— (4,6 -1,1 y)· 104 T.

Aus der von freien Ladungsträgern hervorgerufenen kontinuierlichen Absorption im mittleren Spektralbereich lassen sich die effektiven Elektronenmassen im Leitungsband abschätzen. Sie fallen monoton von InP über die Mischkristalle zu InAs.

Reststrahlmaxima im langwelligen Bereich der Reflexionsspektrogramme geben die Frequenzlage der Eigenschwingungen des Gitters und ermöglichen eine Aussage über den polaren Anteil der Bindung.

The zinc-finger protein KCMF1 is overexpressed during pancreatic cancer development and downregulation of KCMF1 inhibits pancreatic cancer development in mice

Potassium channel modulatory factor 1 (KCMF1) was found upregulated in a differential screen in the metaplastic epithelium in the pancreas of transforming growth factor (TGF)-alpha transgenic mice. Expression analysis indicated broad overexpression in human cancer tissues. Therefore, we investigated the hypothesis that KCMF1 promotes metaplastic changes and tumor development. KCMF1 represents an evolutionarily highly conserved protein with a 95% identity between human and zebrafish. KCMF1 is expressed during embryonic development and in the majority of adult tissues investigated. Upregulation of nuclear KCMF1 expression is evident in preneoplastic lesions and in several epithelial malignancies, such as pancreatic cancer in mice and humans. In cell culture and in the chicken chorioallantoic membrane model, KCMF1 enhances proliferation, migration and invasion of HEK-293 and Panc1 cells. In crossbreeding experiments, KCMF1-knockdown gene trap mice showed a reduced number and size of premalignant lesions and absence of pancreatic cancer formation in TGF-alpha transgenic mice. This effect is related to the decreased expression of G1 to S cell-cycle regulators such as cyclin D and cyclin-dependent kinase (CDK) 4. Our data support the hypothesis that KCMF1 mediates pro-oncogenic functions in vitro and in vivo and downregulation of KCMF1 results in the inhibition of pancreatic cancer formation in mice. These effects are mediated through downregulation of cell-cycle control genes such as cyclin D and CDK4.

CD147 silencing inhibits lactate transport and reduces malignant potential of pancreatic cancer cells in in vivo and in vitro models

BACKGROUND

CD147 (basigin, EMMPRIN) is a multifunctional, highly conserved glycoprotein enriched in pancreatic ductal adenocarcinomas (PDACs) which is associated with poor prognosis in many malignancies. The role of CD147 in pancreatic cancer, however, remains elusive.

METHODS AND RESULTS

Silencing of CD147 by RNA interference (RNAi) reduced the proliferation rate of MiaPaCa2 and Panc1 cells. CD147 is required for the function and expression of the monocarboxylate transporters MCT1 and MCT4 that are expressed in human PDAC cells as demonstrated by real-time reverse transcription-PCR (RT-PCR) as well as immunohistology. MCT1 and MCT4 are the natural transporters of lactate, and MiaPaCa2 cells exhibited a high rate of lactate production, which is characteristic for the Warburg effect, an early hallmark of cancer that confers a significant growth advantage. Further induction of lactate production by sodium azide in MiaPaCa2 cells increased MCT1 as well as MCT4 expression. CD147 silencing inhibited the expression and function of MCT1 and MCT4 and resulted in an increased intracellular lactate concentration. Addition of exogenous lactate inhibited cancer cell growth in a dose-dependent fashion. In vivo, knock-down of CD147 in MiaPaCa2 cells by inducible short hairpin RNA (shRNA)-mediated CD147 silencing reduced invasiveness through the chorioallantoic membrane of chick embryos (CAM assay) and inhibited tumourigenicity in a xenograft model in nude mice.

CONCLUSION

The function of CD147 as an ancillary protein that is required to sustain the expression and function of MCT1 and MCT4 is involved in the association of CD147 expression with the malignant potential of pancreatic cancer cells exhibiting the Warburg effect.

The Notch signaling pathway: transcriptional regulation at Notch target genes

The Notch gene encodes a transmembrane receptor that gave the name to the evolutionary highly conserved Notch signaling cascade. It plays a pivotal role in the regulation of many fundamental cellular processes such as proliferation, stem cell maintenance and differentiation during embryonic and adult development. After specific ligand binding, the intracellular part of the Notch receptor is cleaved off and translocates to the nucleus, where it binds to the transcription factor RBP-J. In the absence of activated Notch, RBP-J represses Notch target genes by recruiting a corepressor complex. Here, we review Notch signaling with a focus on gene regulatory events at Notch target genes. This is of utmost importance to understand Notch signaling since certain RBP-J associated cofactors and particular epigenetic marks determine the specificity of Notch target gene expression in different cell types. We subsequently summarize the current knowledge about Notch target genes and the physiological significance of Notch signaling in development and cancer.

[The compatibility of housing needs and housing conditions and and its impact on experiencing attachment to a district]

Based on the "complementary-congruence model" of person-environment (p-e) fit, this study focuses on housing in old age as an interaction between housing needs and housing conditions in urban settings. The research aims are: (1) To establish a set of housing-related p-e fit indices based on the relationship between environmental needs and existing conditions in different physical and social domains, and to describe housing among elders aged 51-80 years and in different urban districts with these indices. The study distinguishes between basic, higher-order and social needs relating to housing; (2) To explain outdoor place attachment as an indicator for quality of life in different urban districts with a set of predictors including these person-environment fit indices. Data were drawn from telephone-based interviews with 365 older adults (51-80 years) who were questioned about individual housing needs and housing conditions. Results revealed higher p-e fit scores in the domains of higher-order and social housing needs and conditions in the districts which were considered to be more pleasant but had poor access to the city and to public transportation. In contrast, age was more important in explaining differences in the domain of basic housing needs and conditions with higher p-e fit scores among older participants in all settings. In explaining outdoor place attachment, the fit between basic and social housing needs and conditions was important, but the higher-order fit did not play a role.

[Age as a predictor of everyday environmental demands in old age]

Across the lifespan, different environmental contexts may, in the long term, affect health and well-being. Exactly which contextual demands translate into different aspects of self-reported everyday demands has hardly been examined. In this telephone-based study with 365 adults between 51 and 80 years, we assessed (a) age differences in the existing everyday demands, (b) relations between different measures of everyday demands, and (c) the correlational patterns between measures of everyday contexts and everyday demands. Results demonstrate age effects in all measures of everyday demands, and differences between measures. The findings suggest age-related differences in the correlational patterns between specific everyday contexts and the levels of everyday demands.

p300 acts as a transcriptional coactivator for mammalian Notch-1

Notch-1 belongs to a family of transmembrane receptor proteins that direct the decisions as to various cell fates. After ligand binding, a proteolytic cleavage step occurs and the intracellular part of Notch-1, Notch-1-IC, translocates into the nucleus, where it targets the DNA binding protein RBP-J kappa/CBF1. RBP-J kappa mediates repression through recruitment of a histone deacetylase-containing complex. The Notch-1-IC/RBP-J kappa complex overcomes repression and activates the transcription of Notch target genes. We have identified a novel domain in Notch-1-IC, the EP domain, which is indispensable for full transcriptional activation. This transactivation domain is localized adjacent to the ankyrin repeats of Notch-1-IC. In cotransfection experiments, Notch-1-IC-mediated transcriptional activation was inhibited by E1A12S and p53, two proteins, which interfere with the function of the common coactivator p300. Protein-protein interaction assays demonstrated the association of Notch-1-IC and the CH3 region of p300. In addition, the interaction of mammalian Notch-1-IC with p300 was destabilized after deletion of the EP domain of Notch-1-IC. Based on physical interaction with Notch-1-IC and coactivator functions of p300, we propose a model for Notch-1-mediated gene regulation via p300.

Survival of Chlamydia pneumoniae-infected Mono Mac 6 cells is dependent on NF-kappaB binding activity

The respiratory tract pathogen Chlamydia pneumoniae has been associated with atherosclerosis. Monocytes are supposed to serve as a vehicle for systemic dissemination of intracellular C. pneumoniae from the lung to the artery vessel wall. We were therefore interested in pathogen-induced cellular events associated with NF-kappaB, a crucial transcription factor for both inflammatory cytokines and antiapoptotic molecules. In this study we demonstrate by electrophoretic mobility shift assay that C. pneumoniae infection of the human monocytic cell line Mono Mac 6 induces activation of NF-kappaB over 48 h, with a maximum level at 1 h postinfection. As shown by supershift assay, the activated NF-kappaB complex consists of the subunits RelA (p65) and NF-kappaB1 (p50). Apoptotic host cells were not detected during the early stages of the infection when maximal activation of NF-kappaB was detected. Pretreatment of Mono Mac 6 with the antioxidant and NF-kappaB inhibitor PDTC (pyrrolidine dithiocarbamate) induced activation of caspase-3 and led to apoptotic cell death. The C. pneumoniae-induced activation of the NF-kappaB complex was reduced by PDTC, which in parallel resulted in an increased apoptosis, as quantified by annexin V labeling and terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling reaction. In the complete absence of activated NF-kappaB, when Mono Mac 6 cells were pretreated with the more potent NF-kappaB inhibitors MG-132 and parthenolide a C. pneumoniae-mediated rescue of cells from induced apoptosis could not be achieved. Our results indicate that activation of NF-kappaB in C. pneumoniae-infected Mono Mac 6 cells is associated with protection of Mono Mac 6 cells against apoptosis and might thereby contribute to systemic spread of the pathogen.

[Psychosocial competence of general practitioners in managing psychiatric patients: initial results of a questionnaire study]

OBJECTIVE

Given the frequency of patients with psychosocial problems and mental disorders in primary care our study focuses on the relationship between the psychosocial qualifications of general practitioners and their management of these patients.

METHOD

A questionnaire was sent to all general practitioners in Hessen asking for sociodemographic and profession-related data as well as their psychosocial competence and their procedure during a regular day in practice. Based on 396 questionnaires we compared five groups of general practitioners with different psychosocial qualifications, proportionate incidence of diagnoses, medical procedures and referrals to specialists and hospitals.

RESULTS

The average age of the participants of our study is 45 years, they have been working for 14 years. 163 general practitioners without and 59 with a special interest in psychosocial qualification and 174 psychosocially qualified physicians participated in the study. Of a total of 65 patients seen during the reference day 18 were diagnosed as suffering from mental disorders. Their number increased with greater psychosocial competence of the physicians. Psychosomatic and reactive disorders are the most frequent mental disorders to be seen in primary care with nearly 60%. Verbal therapy is often applied, procedures of the so-called psychosomatic basic care and prescription of psychotropic drugs play only a minor role. Nearly every fourth patient is referred to other specialists, referrals for inpatient treatment occur with 1.3% only.

DISCUSSION

Because of the low response rate our study is not representative. Nevertheless the results permit some conclusions concerning the relationship between psychosocial qualification of general practitioners and their management of patients with mental disorders.

Psychosocial consequences of age-related visual impairment: comparison with mobility-impaired older adults and long-term outcome

Indices of behavioral competence (activities of daily living [ADLs], instrumental activities of daily living [IADLs], use of outdoor resources, leisure activity level) as well as emotional adaptation (subjective well-being, future orientation) were used to investigate the psychosocial consequences of age-related vision impairment in a threefold manner: (a) comparison of visually impaired and unimpaired elders, (b) comparison of visually impaired and mobility-impaired elders, and (c) long-term adaptation across 5 years. The research design used (a) 42 severely visually impaired elders, (b) 42 blind elders, (c) 42 mobility-impaired elders, and (d) 42 unimpaired elders. Compared with the mobility impaired, the visually impaired demonstrated lower IADL competence but no difference in emotional adaptation. The long-term adjustment of the visually impaired remained relatively stable in the behavioral domain, although lower compared with the unimpaired elders. Emotional adaptation decreased over the 5-year longitudinal interval in the visually impaired and the unimpaired group, but the decrease was generally higher in the visually impaired group. Conceptual ideas from environmental gerontology as well as psychological resilience are used to interpret these results.

Everyday competence in visually impaired older adults: a case for person-environment perspectives

In this article, the need for an explicit consideration of the environment in order to address everyday competence (EC) in old age is illustrated based on an analysis of the day-to-day challenges of visually impaired older adults. Data are based on a sample of elderly adults suffering from different degrees of visual impairment (visually severely impaired vs blind, each N = 42) and a control group of visually unimpaired elderly persons (N = 42) with age means between 74.9 and 76.8 years. Findings underscore that: (a) EC, regarded as an outcome, is negatively affected by low person-environment fit in the home environment in visually impaired older adults but not in the visually unimpaired elderly population; (b) EC, understood as daily compensatory processes, is more pronounced in the visually impaired with respect to some compensation modes (e.g., use of latent skills), but not all; and (c) EC, as a predictor variable for outdoor behavior, assumes a particularly critical role when outside environmental press is high.

[Every day life experiences of healthy and mobility impaired elderly patients]

Studies on the everyday life of the elderly often deal with visible behavior. In this study, the subjective experience of the everyday living environment was investigated, paying special consideration to the role of mobility impairment. Two approaches, one oriented toward the subject's experience of the home environment, another oriented toward the environmental specifics of the individual's favorite place, were employed. Is the experience of living at home different for individuals with various levels of competence? Which aspects are perceived to be the most important? 84 men and women aged 62-92 years (M = 77 years) participated in the study. 42 persons were generally healthy; the other 42 subjects suffered from severe mobility impairment. The experience of the everyday environment was assessed in semistructured interviews at home. A content analysis of the data gathered using the person-oriented approach resulted in five experiential categories. Differences between healthy and mobility impaired adults were found in the experience of cognitive, biographical, and spatial dimensions of the living environment. Similarities were found in the experience of emotional, social, and behavioral dimensions of one's home. Competence loss played an important role in how the subjects experienced living at home, yet even the mobility impaired experienced their home as an environment which could be shaped. The environment-oriented approach showed that the favorite place of mobility impaired persons was characterized by higher spatial density. Finally, an examination of four home environment profiles using cluster analysis illustrated the connection between both person- and environment-oriented approaches and offered insights into a transactional perspective of person and environment. Even though the subjective experience of one's home environment is not easily quantifiable in terms of maintaining everyday competence, it nonetheless imparts meaning to the elderly person's daily life.

[Deteriorating vision in the elderly: double stress?]

BACKGROUND

Epidemiologic studies have provided clear evidence that the majority of people affected by severe visual impairment are adults above the age of 60 years. The goal of this psychological research was to analyze the emotional and behavioral consequences of age-related visual impairment in three steps: descriptive data concerned with subjective well-being, depression, everyday competence, and leisure as well as explanations of interindividual variability based on individual and environmental variables are presented (study I). Also, the impact of the time of onset (early versus late in life) is addressed (study II). Finally, the role of the living accomodation (institutional versus private household) was the main target of another study (study III).

MATERIALS AND METHODS

Study I was based on 84 elderly adults who experienced an irreversible visual loss after age 55 years; a control group of unimpaired elderly adults is also included (mean age 75.8, range 59 to 92). In study II, 18 elderly adults who had been blind since their early childhood were compared to nine matched elderly adults who experienced blindness in their later life as well as nine matched unimpaired elderly adults (mean age 71.7, range 63 to 83). The data for study III came from 15 visually impaired institutional residents who were compared to 15 matched unimpaired residents and 15 matched visually impaired and 15 unimpaired older adults living in private households (mean age 87.0, range 78 to 93). All subjects underwent an intensive psychological measurement program.

RESULTS

The findings of study I emphasize that age-related visual impairment is associated with lower subjective well-being, greater depression, reduced everyday competence, and lowered leisure activity level. A significant portion of interindividual variability in these outcomes can be explained by addressing individual variables (e.g., comorbidity) as well as environmental variables (e.g., quality of the dwelling unit). Study II data offer evidence that older adults suffering from blindness since their early childhood are better adapted than older adults who experienced blindness only in their later years. Study III shows that visually impaired institutional residents reveal deficits in everyday competence and social contacts as contrasted with their unimpaired counterparts, whereas no difference is observed in the domain of subjective well-being.

CONCLUSIONS

All three studies point to the negative impact of age-related visual impairment on emotional and behavioral adaptation in later life. This highlights the need for a whole range of rehabilitative efforts, including psychosocial elements, which are described in the final part of this article.

NF-kappaB2 is a putative target gene of activated Notch-1 via RBP-Jkappa

NF-kappaB2 (p100/p52), a member of the NF-kappaB/Rel family of transcription factors, is involved in the regulation of a variety of genes important for immune function. Previously, we have shown that the NF-kappaB2 gene is regulated in a positive and a negative manner. Two kappaB elements within the NF-kappaB2 promoter mediate tumor necrosis factor alpha-inducible transactivation. In addition, we have shown that there exists a transcriptional repression in the absence of NF-kappaB. To identify a DNA binding activity responsible for this transcriptional repression, we have partially purified a nuclear complex, named Rep-kappaB. Here we further analyze this putative repressive binding activity. Detailed examination of Rep-kappaB-DNA interaction revealed the sequence requirements for binding to be almost identical to those of recombination signal binding protein Jkappa (RBP-Jkappa), the mammalian homolog of the protein encoded by Drosophila suppressor of hairless [Su(H)]. In addition, in electromobility shift assays, Rep-kappaB binding activity is recognized by an antibody directed against RBP-Jkappa. By performing transient-transfection assays, we show that human RBP-Jkappa represses basal as well as RelA (p65)-stimulated NF-kappaB2 promoter activity. Studies in Drosophila melanogaster have shown that Su(H) is implicated in the Notch signaling pathway regulating cell fate decisions. In transient-transfection assays we show that truncated Notch-1 strongly induces NF-kappaB2 promoter activity. In summary, our data clearly demonstrate that Rep-kappaB is closely related or identical to RBP-Jkappa. RBP-Jkappa is a strong transcriptional repressor of NF-kappaB2. Moreover, this repression can be overcome by activated Notch-1, suggesting that NF-kappaB2 is a novel putative Notch target gene.

The E2F transcription factor activates a replication-dependent human H2A gene in early S phase of the cell cycle

Histone gene expression is restricted to the S phase of the cell cycle. Control is mediated by a complex network of sequence-specific DNA-binding factors and protein-protein interactions in response to cell cycle progression. To further investigate the regulatory functions that are associated at the transcriptional level, we analyzed the regulation of a replication-dependent human H2A.1-H2B.2 gene pair. We found that transcription factor E2F binds specifically to an E2F recognition motif in the H2A.1 promoter region. Activation of the H2A.1 promoter by E2F-1 was shown by use of luciferase reporter constructs of the intergenic promoter region. Overexpression of the human retinoblastoma suppressor gene product RB suppressed E2F-1 mediated transcriptional activation, indicating an E2F-dependent regulation of promoter activity during the G1-to-S-phase transition. Furthermore, the activity of the H2A.1 promoter was also downregulated by overexpression of the RB-related p107, a protein that has been detected in S-phase-specific protein complexes of cyclin A, E2F, and cdk2. In synchronized HeLa cells, expression of luciferase activity was induced at the beginning of DNA synthesis and was dependent on the presence of an E2F-binding site in the H2A.1 promoter. Together with the finding that E2F-binding motifs are highly conserved in H2A promoters of other species, our results suggest that E2F plays an important role in the coordinate regulation of S-phase-specific histone gene expression.

[The importance of the home for healthy and disabled elderly persons]

The majority of old people live in private households and they want to remain there. Starting from this insight, the study is focused on the interaction between older people and their home environment. Some theoretical assumptions on the role of housing are presented, namely the competence theory perspective, the continuity theory perspective, the perspective of research on leisure time and everyday life activities, the environmental adaptation perspective, and the environmental gerontology perspective. Previous research has shown that there is a strong correlation between environmental-relevant competence loss (e.g., mobility impairment) and objective living arrangements. Little attention has been paid, however, to the subjective meaning of home in old age (e.g., processes like familiarity or stimulation), either with or without competence loss. This paper presents preliminary results of an investigation into that "Aging in Place" issue, based on semi-structured interviews with 84 participants between the age of 62-92 (M = 77 years). Forty-two subjects were in good health status, 42 suffered from severe mobility impairments. The participants were visited at home and all interviews were tape-recorded. On one hand, the general meaning of home, on the other, specific sections of the home environment were analyzed (most favorite place within the home, favorite meaningful things). The results revealed that the two groups of participants are similar as far as the general meaning of home is concerned. In the experience of the most favorite place at home, subjects suffering from mobility impairments are tending more to an environmental "centralization" than healthy subjects do. With respect to personal objects, the most often mentioned meaning was "reminiscence". By and large, the results of this work support the view that knowledge about the meaning of home can be of help to better understand how old people create their meaningful everyday life at home and why they want to "stay put"; in addition, the results can be used in planning living arrangements for people of all ages.

E2F-dependent regulation of human MYC: trans-activation by cyclins D1 and A overrides tumour suppressor protein functions

Transcription of the human proto-oncogene MYC is repressed in quiescent or non-dividing cells. Upon mitogenic stimulation expression of MYC is rapidly and transiently induced, maintained throughout G1, and declines to a basal level throughout further cell cycle transitions. Regulation of MYC promoter activity critically depends on the presence of a binding site for transcription factor E2F. Human E2F has been implicated also in the control of cell cycle progression through it association with the retinoblastoma suppressor gene product RB, and with multimeric protein complexes containing the G1-S- and S-phase cyclins E and A, respectively. Using CAT reporter co-transfection assays we show here that transcription from the MYC P2 promoter is induced efficiently by E2F-1, but repressed by RB. Furthermore, overexpression of cyclin A strongly activates the MYC promoter and this effect is further enhanced by coexpression of E2F-1 and cyclin A. We also find that expression of G1-phase cyclin D1 leads to an E2F binding site-dependent trans-activation of the MYC promoter and that this activation can be abrogated by overexpression of RB. The interaction of D-type G1 cyclins with RB resembles that of the adenovirus E1A protein with RB in that it can disrupt inhibitory E2F-RB complexes. Our results support a model in which intervention of distinct cyclins and their respective associated kinases promotes transcriptional activation of MYC throughout the cell cycle either by conversion of E2F within multimeric complexes into an active transcription factor or by liberation of free functional E2F.

[Report on the aged in the Federal government]

The Department of Youth, Women, Family, and Health called in a commission to prepare the 1st report on the situation of the elderly in the Federal Republic of Germany in 1989. The report is parted into two. The first part, which was finished in May 1990, essentially deals with "competence", "prevention", and "rehabilitation" in old age. It applies to the Germany of the time before October 3rd, 1990. The second part is to be presented until June 1992. The work on the report was influenced by the reunification of Germany. New members of the eastern part of the country joined the commission. Due to this, regional differences will be taken into consideration.

[Aged subjects' personal image of elderly people]

Many findings demonstrate a negative image toward old people in our society. "Being-old" is characterised by many negative stereotypes. The elderly are often seen as victims or targets of discrimination against the aged ("ageism"). We also find self-discrimination in the elderly's image of "being-old"; this could be a result of assimilating the general image of "being-old" in our society to the self-concept of the elderly. We asked 30 persons, 63-96 years old, to give a description of "being-old". Our participants differed in sex, health status, and social housing conditions (number of persons living together). The given aspects of "being-old" had to be semantically described and evaluated. We got 279 aspects of "being-old" which we put into 13 categories. We did not find a generally negative image of "being-old". All participants did not assess themselves as being "old", regardless of their age. The most frequently cited aspects of "being-old" were "physical and mental activity", "achievement-relation" and "autonomy", but not "disease" or "decrease of power". As far as they are concerned, aspects of "having time and calmness" were more often mentioned than aspects of "being-religious" or thinking about "dying and death". Participants living with their partners or family members more often talked about themselves than singles did when they explained a given aspect of "being-old" to the interviewer. Those who live without health problems more often talked about diseases than ill participants did. Women more frequently explained self evaluation of health problems to the interviewer than men.

Evaluation of different 15N-tracer substances for calculation of whole body protein parameters in infants

The validity of using different 15N-tracer substances to measure whole body protein parameters, i.e., protein synthesis, protein breakdown, net protein gain, protein turnover, metabolic pool, and reutilization, was assessed by comparing the results obtained with: [15N]glycine, a mixture of 10 15N-labeled amino acids, and a 15N-labeled chicken egg protein in two infants, 9 and 12 weeks old, who were fed human milk. The tracer substances were fed orally as a single dose corresponding to a 15N-excess quantity of 0.2 mmol X kg-1 body weight. 15N Excretion in the urine was measured cumulatively by emission spectrometry, and the data on the protein metabolism were calculated by means of a three-pool model. All three tests yielded consistent net protein gains. The protein synthesis, protein breakdown, protein turnover, and nitrogen reutilization values produced by the [15N]glycine tracer study were higher than those produced by application of the 15N-amino acid mixture and the 15N-labeled egg protein. However, in our opinion, this discrepancy does not justify the replacement of [15N]glycine by expensive 15N-amino acid mixtures as tracer substances.