Transfer and effects of 1,2,3,5,7-pentachloronaphthalene in an experimental food chain.

Polychlorinated naphthalenes are environmentally relevant compounds that are measured in biota at concentrations in the μg/kg lipid range. Despite their widespread occurrence, literature data on the accumulation and effects of these compounds in aquatic ecosystems are sparsely available. The goal of this study was to gain insights into the biomagnification and effects of 1,2,3,5,7-pentachloronaphthalene (PeCN52) in an experimental food chain consisting of benthic worms and juvenile rainbow trout. Worms were contaminated with PeCN52 by passive dosing from polydimethylsiloxane silicone. The contaminated worms were then used to feed the juvenile rainbow trout at 0.12, 0.25 or 0.50 μg/g fish wet weight/day, and the resulting internal whole-body concentrations of the individual fish were linked to biological responses. A possible involvement of the cellular detoxification system was explored by measuring PeCN52-induced expression of the phase I biotransformation enzyme gene cyp1a1 and the ABC transporter gene abcb1a. At the end of the 28-day study, biomagnification factors were similar for all dietary intake levels with values between 0.5 and 0.7 kg lipid(fish)/kg lipid(worm). The average uptake efficiency of 60% indicated that a high amount of PeCN52 was transferred from the worms to the fish. Internal concentrations of up to 175 mg/kg fish lipid in the highest treatment level did not result in effects on survival, behavior, or growth of the juvenile trout, but were associated with the induction of phase I metabolism which was evident from the significant up-regulation of cyp1a1 expression in the liver. In contrast, no changes were seen in abcb1a transcript levels.

Cleavage and activation of calpain and its substrate caspase-7 in prostate cancer cells: Evidence for a role in apoptotic sensitization

Changes in the levels of intracellular calcium mediate multiple biological effects, including apoptosis, in some tumor cells. Early studies demonstrated that prostate cancer cells are highly sensitive to alterations in the levels of their intracellular calcium pools. Furthermore, it has been established that apoptosis in prostate cancer could be initiated through calcium-selective ionophores, or inhibitors of intracellular calcium pumps. High sensitivity to changes in intracellular calcium levels may therefore be exploited as a novel mechanism for controlling prostate cancer apoptotic thresholds; however, the mechanisms associated with this process are poorly understood. To investigate the role of calcium as a mediator of prostate cancer cell death and its effects on caspase activation, LNCaP and PC-3 cell response to the calcium ionophore A23187, were examined. LNCaP cells were highly sensitive to changes in intracellular calcium, and subtoxic concentrations of A23187 facilitated apoptosis initiated by cytokines (TNF or TRAIL). In contrast, PC-3 cell death was not affected by A23187 or cytokines. A23187 caused rapid and concentration-dependent activation of calpain in LNCaP (but not PC-3 cells) which correlated with cleavage of calpain substrates caspase-7 and PTP1B. Cleavage of PTP1B from a 50 kDa to 42 kDa protein correlated with its translocation from the endoplasmic reticulum to the cytosol and with inhibition of tyrosine phosphorylation. Caspase-7 was cleaved from a 35 kDa to 30 kDa protein in response to A23187 in LNCaP (but not PC-3) cells and correlated with activation of both upstream and downstream caspases. Extracts from A23187-treated LNCaP cells, or PC-3 cells transiently transfected with calpain, mediated similar processing of in vitro transcribed and translated (TNT) caspase-7. In vitro processing of caspase-7 correlated with its proteolytic activation, which was inhibited by calpain inhibitor (calpeptin) and to some degree, by caspase inhibitors (zVAD, DEVD). Together, these results suggest that calpain is directly involved in calcium-mediated apoptosis of prostate cancer cells through activation and cleavage of caspase-7 and other substrates. Loss of calpain activation may therefore play a critical role in apoptotic resistance of some prostate cancer cells. ^

An Inexpensive Alternative to CS Photoshop & Bridge: Archival Master Image Capture and Batch Derivative Creation in Canon Scan Gear & Adobe Photoshop Elements 7

This presentation was made at the Connecticut State Library Service Center, Willimantic, CT, April 14, 2009. It focused on digital capture workflows for both archival and derivative image creation using accepted current standards. Tools used were inexpensive by choice and focused towards the needs of small to mid-sized cultural heritage institutions who wish to begin digital capture in their own facilities.

Na 1 Nachlass Max Horkheimer, 7 - Korrespondenzen u.a. mit Familie Cahn (p. I 4, 1-297a)

1 Brief von Max Horkheimer an die Cadillac Motor Division, 05.06.1939; 148 Briefe zwischen Erwin Cahn, Lotte Cahn, Ilse Cahn, Max Cahn, Lilo Cahn, Lina Cahn und Max Horkheimer, 1938-1942; 10 Briefe zwischen dem Transmigration Bureau og the American Jewish Joint Distribution Committee und Friedrich Pollock, 1941-1942; 3 Briefe zwischen dem National Refugee Service und Max Horkheimer, 07.04.1941, 1941; 1 Brief von Julius S. Bach an die National City Bank of New York, 27.06.1940; 1 Brief von Julius S. Bach an den American Consul General Berlin, 15.04.1940; 1 Brief von Max Horkheimer an Julius S. Bach, 15.05.1940; 16 Briefe von Max Horkheimer an den American Consul General Stuttgart, 1938-1941; 2 Briefe zwischen der Auswandererstelle Marx und Max Horkheimer, 02.06.1941; 5 Briefe zwischen dem Reisebüro Anselm Stuttgart und Max Horkheimer, 1941; 9 Briefe zwischen der Sapt A.G und Max Horkheimer, 1940-1941; 3 Briefe zwischen Emanuel Green und Max Horkheimer, 26.09.1940, 1940; 3 Briefe zwischen der Zweigstelle Wüttemberg der Reichsvereinigung der Juden in Deutschland und Max Horkheimer, 1940, 19.09.1940; 2 Briefe zwischen der Auswandererstelle Adler und Max Horkheimer, 25.05.1940; 2 Briefe von Max Horkheimer an den American Consul General Berlin, 1939; 1 Brief von Max Horkheimer an S. Klein, 20.03.1939; 1 Brief von Max Horkheimer an den Collector of Customs, 27.02.1939; 1 Brief von Max Horkheimer an Ludwig Lewisohn,. 03.01.1939; 1 Brief von Friedlaender an Kahn, 15.12.1938; 1 Brief von Erwin Cahn an Max Horkheimer, 07.02.1935;

Na 1 Nachlass Max Horkheimer, 13 - Korrespondenzen u.a. mit Familie Eder (p. I 7, 1-223)

7 Briefe zwischen Edward Mead Earle, American Committee for International Studies, Princeton N. J. und Max Horkheimer, 1940-1941; 3 Briefe zwischen Margaret Ebert und Margot von Mendelssohn, 1941, 28.08.1941; 6 Briefe zwischen C. C. Eckhardt und Max Horkheimer, 1940; 5 Briefe zwischen Kay Eckstein und Max Horkheimer, 1940; 2 Briefe zwischen George Eckstein und Max Horkheimer, 16.05.1939, 35.05.1939; 1 Brief von F. K. Eden an Max Horkheimer, 02.04.1944; 33 Briefe zwischen Leopold Eder, Frieda Eder, Ruth Eder und Max Horkheimer, 1937-1940; 2 Briefe zwischen Dale Edwards und Max Horkheimer, 16.07.1940; 1 Brief von Hedwig Ehrlich an Max Horkheimer; 1 Brief von Max Horkheimer an Albert Einstein, 20.02.1935; 1 Brief von Max Horkheimer an W. Eisemann, 02.11.1939; 1 Brief von Else Eisner an Max Horkheimer, 09.12.1935; 2 Briefe zwischen Edit Elbogen und Max Horkheimer, 24.03.1942, 26.03.1942; 1 Brief von Käte von Hirsch an Max Horkheimer, 03.08.1941; 2 Briefe von Emmy Elbogen an Margot von Mendelssohn, 1945; 2 Briefe zwischen Paul Elbogen und Max Horkheimer, 02.06.1944, 09.06.1944; 4 Briefe zwischen Norbert Elias und Max Horkheimer, 1934-1935; 1 Brief von Werner B. Ellinger an Max Horkheimer, 16.12.1937; 19 Briefe zwischen dem Emergency Committee in Aid of Displaced Foreign Scholars New York und Max Horkheimer, 1938-1944; 2 Briefe zwischen dem Emergency Rescue Committee New York und Max Horkheimer, 12.06.1941, 14.06.1941; 1 Brief von F.L. Neumann an Emhardt, 13.02.1939; 23 Briefe zwischen Alice Engel und Max Horkheimer, 1937-1941; 9 briefe zwischen Paul Doernberg, Sofie Doernberg und Max Horkheimer, 1940-1942; 3 Briefe zwischen der Hebrew Sheltering and Immigrant Aid Society New York und Max Horkheimer, 05.01.1942, 1942; 1 Brief von der Selfhelp of Emigres from Central Europe, New York an Max Horkheimer, 18.08.1941; 2 Briefe zwischen R. Weissmann und Max Horkheimer, 09.01.1941, 03.02.1941; 5 Briefe zwischen Ernst Engelberg und Max Horkheimer, 1939-1940, 07.06.1939; 1 Brief von Fritz Epstein an Max Horkheimer, 10.04.1937; 1 Brief von Erika Ermel an Max Horkheimer, 15.09.1948; 2 Briefe zwischen Max Ernst und Max Horkheimer, 23.01.1936; 4 Briefe zwischen Margot Esser und Max Horkheimer, 1935-1936; 16 Briefe zwischen Rene Etiemble und Max Horkheimer, 1936-1938; 4 Briefe zwischen L.M. Ettlinger und Max Horkheimer, 1937; 8 Briefe zwischen Walter Fabien und Max Horkheimer, 1937-1941; 1 Brief von Max Horkheimer an Henry Pratt Fairchild, 25.03.1941; 2 Briefe zwischen Marvin Farber und Max Horkheimer, 14.03.1940, 17.05.1940; 4 Briefe zwischen Walter Farley udn Max Horkheimer, 1935, 01.10.1935; 8 Briefe zwischen Alexander Farquharson und Max Horkheimer, 1935-1939;

Na 1 Nachlass Max Horkheimer, 14 - Korrespondenzen u.a. mit Hugo Fischer und Karl August Wittfogel (p. I 7, 224-429)

1 Brief von Max Horkheimer an Rosel Favez, 03.12.1935; 5 Briefe zwischen Sidney B. Fay von der Bureau of International Search Cambridge, Massachusetts und Max Horkheimer, 1939-1941; 1 Brief von Max Horkheimer an James Feibleman, 02.03.1942; 5 Briefe von Hans Feibelmann an Max Horkheimer, 1936-1937; 2 Briefe zwischen Babette Feigenbaum und Max Horkheimer, 29.04.1941, 05.05.1941; 1 Brief von Arthur Feiler an Max Horkheimer, 15.10.1939; 1 Brief von Max Horkheimer an Adolf Feitler, 03.01.1935; 3 Briefe zwischen Frederick V. Filed von dem American Council Institute of Pacific Relations und Max Horkheimer, 1937, 05.04.1937; 9 Briefe zwischen Thea Field, Lowell Field und Max Horkheimer, 1935-1941; 1 Brief von Max Horkheimer an Finkelstein, 18.09.1941; 7 Briefe zwischen Harry Finkelstein und Max Horkheimer, 1936-1940; 1 Brief von Louis Finkelstein an Robert MacIver, 29.05.1940; 2 Briefe zwischen Louis Finkelstein und Max Horkheimer, 06.06.1940, 04.06.1940; 15 Briefe zwischen Hugo Fischer und Max Horkheimer, 1937-1938; 1 Brief von Hugo Fischer an P. Tillich; 1 Brief von Hugo Fischer an Karl A. Wittfogel, 17.06.1940; 2 Briefe von Max Horkheimer an Ernest Manheim, April 1942; 1 Brief von Alexander Farquharson an Max Horkheimer, 20.01.1940; 3 Briefe zwischen dem Institute of International Education, New York Edgar J. Fisher und Max Horkheimer, Oktober 1938, 18.10.1938; 10 Briefe zwischen Paul Fischer und Max Horkheimer, 1938-1940; 2 Briefe zwischen der Hessian Hills School New York und Max Horkheimer, 21.02.1938, 28.02.1938; 2 Briefe zwischen Dorothy Canfield Fisher und Max Horkheimer, 24.01.1939, 19.01.1939; 1 Brief von Ossip K. Flechtheim an Max Horkheimer, 04.01.1941; 2 Briefe zwischen der University of Minnesota, Minneapolis und Max Horkheimer, 02.08.1945, 15.09.1945; 3 Briefe zwischen Leo Löwenthal und Max Horkheimer, 1943-1945, 17.08.1945; 2 Briefe zwischen der University of Denver, Colorado und Max Horkheimer, 11.05.1943, 28.05.1943; 1 Brief von dem Institute Universitaire De Hautes Etudes Internationales Genf an Max Horkheimer, 25.01.1939; 1 Brief von Hans Kelsen an Max Horkheimer, 30.01.1939; Lebenslauf und 2 Empfehlungsschreiben von Max Fleischmann für Prof. Edwin Borchard; 1 Brief von der Columbia University in the City of New York an Franz Neumann, 17.04.1940; 3 Briefe zwischen Philipp Flesch und Max Horkheimer, 26.03.1940, 1939-1940; 17 Briefe zwischen Babette Fletcher, Theo Fletcher und Max Horkheimer, 1941-1950; 1 Brief von Max Horkheimer an Abraham Flexner, 07.06.1939; 1 Brief von Robert Fließ an Max Horkheimer, 24.10.1938; 1 Brief von der Foreign Policy Association New York an Max Horkheimer, 03.11.1934; 1 Brief von Max Horkheimer an Rudolf Forster, 10.01.1940; 2 Briefe von der Fortune Time & Life Building New York und Max Horkheimer, 1938-1940; 4 Briefe zwischen Siegmund H. Foulkes (Fuchs) und Max Horkheimer, 1936-1937, 31.12.1936; 5 Briefe zwischen Elsie M. Foulstone und Max Horkheimer, 1941; 1 Brief von Mary Fox an Max Horkheimer, 09.12.1938; 5 Briefe zwischen Ernst Fraenkel und Max Horkheimer, 1936-1938; 1 Heiratsanzeige Liesl Frank; 7 Briefe zwischen Philipp Frank und Max Horkheimer, 1937-1939; 6 Briefe zwischen Lothar G. Frank und Max Horkheimer, 1941; 7 Briefe zwischen Felix Frankfurter und Max Horkheimer, 1937-1941; 2 Briefe zwischen Joseph Freeman und Max Horkheimer, 22.11.1944; 1 Brief von der Free Synagogue New York an Max Horkheimer, 14.11.1938; 2 Briefe zwsichen Benjamin Freilichmann und Max Horkheimer, 07.01.1939, 23.01.1939; 2 Briefe zwischen dem Frenkel Travel Service New York und Max Horkheimer, 21.02.1936, 23.02.1936; 2 Briefe zwischen Hugo Freund und Max Horkheimer, 14.11.1938, 18.11.1938; 2 Briefe zwischen Julius A. Jr. Freynick und Max Horkheimer, 11.09.1939, 18.09.1939;

Na 50 Nachlass Arthur Schopenhauer - 'Schopenhauer-Archiv', 7 - Dankesschreiben anlässlich der Übersendung eines Aufsatzes

u.a.: Immanuel Kant; Georg Christian Weigelt; philosophische Unterscheidung zwischen Wahrnehmung und Empfindung; Kuno Fischer; Jena; Satz vom Grund; Parerga; Georg Carl Rudolph Seydel; Jules Lunteschütz; Schopenhauer-Portrait; Angilbert Göbel;

Na 1 Nachlass Max Horkheimer, 607 - Manuskripte u.a. zur Antrittsvorlesung von Max Horkheimer und verschiedenen Seminaren (p. VIII 3, - VIII 7, 1)

Notizheft, SS 1926, Entwürfe und Notizen für Vorlesung und Seminar, (unter anderem über: Die Aktualität der Philosophie; Philosophie im Verhältnis zu Natur- und Geisteswissenschaften; Neukantianismus; Lebensphilosophie, Manuskript und eigenhändige Notizen, 1 Heft, 30 Blatt, 3 leer, 16 zusätzliche Blatt); Friedrich Pollock: Kollegheft zu einem Colloquium von Max Horkheimer, (unter anderem über die Hegelsche Schule, über Gestalttheorie, SS 1926, eigenhändige Notizen, 1 Heft, 10 Blatt, 5 leer); Einzelne Artikel: "Rudolf Eucken" (1926), Typoskript mit eigenhändigen Korrekturen, 4 Blatt (GS 2, S. 154-7); Einzelne Artikel: "Probleme der modernen Erkenntnistheorie", Typoskript mit eigenhändigen Korrekturen, 5 Blatt; Typoskript mit eigenhändigen Korrekturen, 5 Blatt (GS 11, S. 133-7); "Hans Driesch. Zum 60. Geburtstag" (1927), Typoskript mit eigenhändigen Korrekturen, 5 Blatt, Zeitungsausdruck, Frankfurter Zeitung vom 01.11.1927, 1 Blatt (GS 2, S. 159-161); Übung (WS 1926/27): "Zur Geschichte der Metaphysik seit Hegel", Manuskript, 1 Kollegheft, 14 Blatt, 2 lose Blätter; Antrittsvorlesung: "Kant und Hegel", Vortragsskript, Typoskript mit eigenhändigen Korrekturen, datiert 02.05.1925. 11 Blatt, Manuskript, 1 Heft, 16 Blatt, 1 leer, 2 zusätliche Blätter, datiert 1927 (GS 11, S. 100-118); Vorlesungskonzept (SS 1927): "Geschichte der neueren Philosophie", Verzeichnis der Anmerkungen, Entwürfe, eigenhändige Notizen, 19 Blatt;

Ontogeny and regulation of interleukin-7 expressing thymic epithelial cells

T cell development is a multistage process of differentiation that depends on proper thymocyte-thymic epithelial cell (TEC) interactions. Epithelial cells in the thymus are organized in a three-dimensional network that provides support and signals for thymocyte maturation. Concurrently, proper TEC differentiation in the adult thymus relies on thymocyte-derived signals. TECs produce interleukin-7 (IL-7), a non-redundant cytokine that promotes the survival, differentiation, and proliferation of thymocytes. We have identified IL-7 expressing TECs throughout ontogeny and in the adult thymus by in situ hybridization analysis. IL-7 expression is initiated in the thymic fated domain of the thymic primordium by embryonic day 11.5, in a Foxn1 independent pathway. Marked changes occur in the localization and regulation of IL-7 expressing TECs during development. Whereas IL-7 expressing TECs are present throughout the early thymic rudiment, the majority of IL-7 producing TECs are concentrated in the adult thymic medulla. By analyzing mouse strains that sustain blocks at different stages of thymocyte development, we show that IL-7 expression is initiated independently of hematopoietic-derived signals during thymic organogenesis. However, thymocyte-derived signals play an essential role in regulating IL-7 expression in the adult TEC compartment. Furthermore, distinct thymocyte subsets regulate the expression of IL-7 and keratin 5 in adult cortical epithelium. Intraperitoneal injection of Recombination Activating Gene deficient mice (RAG-2−/−) with anti-CD3ϵ monoclonal antibody (mAb) induces CD4− 8− double negative thymocytes to undergo β-selection and differentiate into CD4+8+ cells. Analysis of the thymic stromal compartment reveals that progression through β-selection renders thymocytes competent to alter the pattern of IL-7 expression in the cortical TEC compartment. RAG-2−/− mice do not generate mature T cells and therefore the RAG-2−/− thymus is devoid of organized medullary regions. Histological examination of RAG-2−/− thymus following anti-CD3ϵ stimulation reveals the emergence of mature thymic medullary regions, as assessed by H & E staining and expression of thymic stromal medullary markers. Stromal medullary reorganization occurs in the absence of T cell receptor αβ expression, suggesting that activation of RAG-2−/− thymocytes by CD3ϵ ligation generates thymocyte-derived signals that induce thymic epithelial reorganization, generating a mature medullary compartment. This model provides a tool to assess the mechanisms underlying thymic medullary development. ^

Genetic epidemiology of gallbladder disease in Mexican Americans and cholesterol 7$\alpha$-hydroxylase gene sequence variation

Among Mexican Americans, the second largest minority group in the United States, the prevalence of gallbladder disease is markedly elevated. Previous data from both genetic admixture and family studies indicate that there is a genetic component to the occurrence of gallbladder disease in Mexican Americans. However, prior to this thesis no formal genetic analysis of gallbladder disease had been carried out nor had any contributing genes been identified.^ The results of complex segregation analysis in a sample of 232 Mexican American pedigrees documented the existence of a major gene having two alleles with age- and gender-specific effects influencing the occurrence of gallbladder disease. The estimated frequency of the allele increasing susceptibility was 0.39. The lifetime probabilities that an individual will be affected by gallbladder disease were 1.0, 0.54, and 0.00 for females of genotypes "AA", "Aa", and "aa", respectively, and 0.68, 0.30, and 0.00 for males, respectively. This analysis provided the first conclusive evidence for the existence of a common single gene having a large effect on the occurrence of gallbladder disease.^ Human cholesterol 7$\alpha$-hydroxylase is the rate-limiting enzyme in bile acid synthesis. The results of an association study in both a random sample and a matched case/control sample showed that there is a significant association between cholesterol 7$\alpha$-hydroxylase gene variation and the occurrence of gallbladder disease in Mexican Americans males but not in females. These data have implicated a specific gene, 7$\alpha$-hydroxylase, in the etiology of gallbladder disease in this population.^ Finally, I asked whether the inferred major gene from complex segregation analysis is genetically linked to the cholesterol 7$\alpha$-hydroxylase gene. Three pedigrees predicted to be informative for linkage analysis by virtue of supporting the major gene hypothesis and having parents with informative genotypes and multiple offspring were selected for this linkage analysis. In each of these pedigrees, the recombination fractions maximized at 0 with a positive, albeit low, LOD score. The results of this linkage analysis provide preliminary and suggestive evidence that the cholesterol 7$\alpha$-hydroxylase gene and the inferred gallbladder disease susceptibility gene are genetically linked. ^

Family Preservation Journal, 2003, Volume 7. (Entire issue)

Entire issue (large pdf file) Articles include: Social Workers' Perceptions of Family Preservation Programs. Elaine M Maccio, David Skiba, Howard J Doueck, Karen A. Randolph, Elisabeth A. Weston, and Lorie E. Anderson Targeting Special Populations for Family Preservation: The Influence of Worker Competence and Organizational Culture. Ramona W: Denby, Keith A. Alford, and Carla M Curtis Understanding and Fostering Family Resilience. Robert G. Blair Walking Our Talk in the Neighborhoods: Building Professional/Natural Helper Partnerships. Jill Kinney and Margaret Trent Intersystem Collaboration: A Statewide Initiative to Support Families. Elizabeth M Tracy, David E. Biegel, Ann C. Rebeck, and Jeffrey A. Johnsen

Characterization of the cholesterol 7$\alpha$-hydroxylase promoter in hypercholesterolemia -resistant rabbits

Our laboratory has developed and partially characterized a strain of New Zealand white rabbits that are resistant to the hypercholesterolemia which typically occurs in normal rabbits when fed a cholesterol-enriched diet. This phenotype is most likely attributed to an increase in bile acid excretion by hypercholesterolemia-resistant (CRT) rabbits as a result of elevated enzyme activity of cholesterol 7$\alpha$-hydroxylase (C7$\alpha$H), the rate-limiting enzyme in bile acid synthesis. Northern analysis revealed that CRT rabbits, in comparison to normal rabbits, have a 7-fold greater steady-state C7$\alpha$H mRNA levels irrespective of dietary regimen. The C7$\alpha$H gene in both phenotypes was determined to be a single copy gene. The hypothesis was that the elevated C7$\alpha$H mRNA levels in CRT rabbits, in comparison to normal animals, was due to an increase in the transcription rate of the C7$\alpha$H gene as a result of a mutation in a cis-acting element and/or a trans-acting factor within the hepatocyte. To isolate the C7$\alpha$H gene from both normal and CRT rabbits, genomic libraries were prepared from both phenotypes into $\lambda$GEM12 vectors using conventional techniques. Three CRT and one normal phage clones that contained the C7$\alpha$H gene were identified by screening the library with a series of probes located within different exons of the C7$\alpha$H cDNA. Sequencing analysis confirmed that approximately 1100 bp of the C7$\alpha$H 5'-flanking region from both normal and CRT phenotypes was identical. The increase in C7$\alpha$H mRNA levels was not attributed to a cis-acting mutation within this region. Liver nuclear extracts were prepared from normal and CRT rabbits maintained either on a basal or 0.25% cholesterol-enriched diet and incubated with several radiolabeled DNA fragments from the C7$\alpha$H gene. A 37 basepair region, located between nucleotides $-$452 to $-$416 was identified that had altered binding patterns between normal and CRT rabbits as a function of diet. Two additional regions, $-$747 to $-$575 and $-$580 to $-$442, produced banding patterns which were identical, irrespective of phenotype or diet. In conclusion, these studies suggested that the increase in C7$\alpha$H mRNA in CRT rabbits was due to differences in binding of a cholesterol-responsive transcription factor to the C7$\alpha$H promoter. ^

Significance of tissue transglutaminase expression in multidrug resistant MCF -7 human breast cancer cells

Tissue transglutaminase (tTGase) is an enzyme that catalyzes the posttranslational modification of proteins via Ca2+-dependent cross-linking reactions. In this study, we extended our earlier observation that tTGase is highly expressed in MCF-7 human breast carcinoma cells selected for the multidrug resistance phenotype (MCF-7/DOX). To directly assess the involvement of tTGase in drug resistance, parental MCF-7 (MCF-7/WT) cells were transfected with cDNAs encoding either a catalytically active (wildtype) or inactive (mutant) tTGase protein. Expression of wildtype tTGase led to spontaneous apoptosis in MCF-7/WT cells, while the mutant tTGase was tolerated by the cells but did not confer resistance to doxorubicin. Analysis of calcium by a spectrofluorometric technique revealed that MCF-7/DOX cells exhibit a defective mechanism in intracellular calcium mobilization, which may play a role in preventing the in situ activation of tTGase and thus allowing the cells to grow despite expressing this enzyme. An elevation in intracellular calcium by treatment with the calcium ionophore A23187 induced rapid and substantial apoptosis in MCF-7/DOX cells as determined by morphological and biochemical criteria. Pretreatment of MCF-7/DOX cells with a tTGase-specific inhibitor (monodansylcadaverine) suppressed A12387-induced apoptosis, suggesting the possible involvement of tTGase-catalyzed protein cross-linking activity. A23187-induced apoptosis in MCF-7/DOX cells was further characterized by PARP cleavage and activation of downstream caspases (-3, -6, and -7). Another interesting aspect of tTGase/A23187-induced apoptosis in MCF-7/DOX cells was that these cells failed to show any prototypic changes associated with the mitochondrial (altered membrane potential, cytochrome c release, caspase-9 activation), receptor-induced (Bid cleavage), or endoplasmic reticulum-stressed (caspase-12 activation) apoptotic pathways. In summary, our data demonstrate that, despite being highly resistant to conventional chemotherapeutic drugs, MCF-7/DOX cells are highly sensitive to apoptosis induced by increased intracellular calcium. We conclude that tTGase does not play a direct role in doxorubicin resistance in MCF-7/DOX cells, but may play a role in enhancing the sensitivity of these cells to undergo apoptosis. ^