Condensation of the chromatin at the membrane of an apoptotic nucleus is not associated with activation of an endonuclease

1993 ◽  
Vol 104 (2) ◽  
pp. 317-326 ◽  
Author(s):  
F. Oberhammer ◽  
G. Fritsch ◽  
M. Schmied ◽  
M. Pavelka ◽  
D. Printz ◽  
...  
Keyword(s):  
Dna Fragmentation ◽  
Early Event ◽  
Tgf Beta ◽  
Hoechst 33258 ◽  
Nucleolar Structure ◽  
Nuclear Changes ◽  
Rigorous Test ◽  
A Current ◽  
Mouse Lymphoma

A current hypothesis holds that chromatin fragmentation into oligonucleosomal patterns is an early event during apoptosis. In contrast, induction of apoptosis in cultured hepatocytes by TGF-beta 1 was not associated with DNA fragmentation into oligonucleosomes in hepatocyte monolayers and apoptotic fragments. For a more rigorous test of the hypothesis we performed a number of experiments. We compared nuclear changes resulting from TGF-beta 1 with those induced by Ca2+, a known activator of endonuclease. The morphology of apoptotic and Ca(2+)-treated nuclei was different as judged by DNA staining with Hoechst 33258. Likewise, electron microscopy of apoptotic nuclei showed characteristic condensation of the chromatin as well as dissolution of the nucleolar structure and nuclear fragmentation, changes not seen after Ca2+ treatment, after three hours of incubation. Analysis of DNA fluorescence of nuclei by FACS revealed that treatment with Ca2+ reduced the signal by 20%. In contrast, nuclei from TGF-beta 1-treated hepatocytes did not exhibit a reduced signal and after sorting by FACS, apoptotic nuclei remained in the 2N and 4N fractions. The absence of detectable DNA fragmentation in apoptotic nuclei was further verified by in situ nick translation, not only in hepatocytes but also in a mouse lymphoma cell line. From these findings we conclude that activation of an endonuclease is not an early event on the pathway to morphologically recognizable apoptosis.

Structure of Palladium Single-Crystal Films Prepared by Flash Evaporation onto (001) NaCl Substrates

1970 ◽  
Vol 28 ◽  
pp. 456-457
Author(s):  
L. E. Murr ◽  
G. Wong
Keyword(s):  
Single Crystal ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
High Rate ◽  
Flash Evaporation ◽  
Optimum Load ◽  
Single Crystal Films ◽  
Crystal Films ◽  
A Current

Palladium single-crystal films have been prepared by Matthews in ultra-high vacuum by evaporation onto (001) NaCl substrates cleaved in-situ, and maintained at ∼ 350° C. Murr has also produced large-grained and single-crystal Pd films by high-rate evaporation onto (001) NaCl air-cleaved substrates at 350°C. In the present work, very large (∼ 3cm2), continuous single-crystal films of Pd have been prepared by flash evaporation onto air-cleaved (001) NaCl substrates at temperatures at or below 250°C. Evaporation rates estimated to be ≧ 2000 Å/sec, were obtained by effectively short-circuiting 1 mil tungsten evaporation boats in a self-regulating system which maintained an optimum load current of approximately 90 amperes; corresponding to a current density through the boat of ∼ 4 × 104 amperes/cm2.

Sample Preparation of Aluminum Bridge Test Vehicles for Tem In-Situ Crystallographic Studies of Electromigration

1987 ◽  
Vol 115 ◽  
Author(s):  
W. E. Rhoden ◽  
J. V. Maskowitz ◽  
D. R. Kitchen ◽  
R. E. Omlor ◽  
P. F. Lloyd
Keyword(s):  
High Temperature ◽  
Sample Preparation ◽  
Integrated Circuit ◽  
Circuit Reliability ◽  
Test Vehicle ◽  
Aluminum Films ◽  
Current Densities ◽  
Integrated Circuit Reliability ◽  
A Current

IntroductionElectromigration in aluminum films has been identified as an increasing concern for integrated circuit reliability. Electromigration is the mass transport of atoms in a conductor under a current stress. Electromigration occurs in conductors experiencing current densities greater than 105 A/cm2 and is accelerated by high temperature. The damage to aluminum films manifests itself in the formation of voids, hillocks and whiskers along the conductor. This paper presents a test vehicle preparation procedure which can be used to investigate electromigration.

The initiation of basal disc formation in Dictyostelium discoideum is an early event in culmination

Development ◽  
1996 ◽  
Vol 122 (3) ◽  
pp. 753-760 ◽  
Author(s):  
K. Jermyn ◽  
D. Traynor ◽  
J. Williams
Keyword(s):  
Early Event ◽  
Double Staining ◽  
Forward Movement ◽  
Basal Disc ◽  
Stage Of Development ◽  
Glucuronidase Reporter ◽  
Tip Formation ◽  
Beta Galactosidase ◽  
Disc Formation

We have analysed expression of the ecmA and ecmB genes of Dictyostelium by enzymatic double staining using beta-galactosidase and beta-glucuronidase reporter gene constructs. Cells expressing the ecmA gene first appear as scattered cells at the mound stage of development and we show that this is also true for cells expressing the ecmB gene. During tip formation the ecmA-expressing cells move to the apex of the mound, while the ecmB-expressing cells accumulate in the base. The ecmB-expressing cells constitute part of the basal disc if the culminant is formed in situ but are discarded if a migratory slug is formed. During slug migration they are replaced by a band of ecmB-expressing cells, situated in the front half of the prespore zone and tightly apposed to the substratum. When culmination is triggered these cells rapidly move to the back half of the prestalk zone, possibly acting as a point of attachment to the substratum. Ultimately, they are joined by cells at the back of the slug, the rearguard cells, to form the basal disc. Thus, contrary to previous belief, basal disc formation is initiated very early during culmination and occurs by the forward movement of cells located in the anterior of the prespore zone.

scholarly journals Expression of mRNA for IL1 beta, IL6 and TGF beta 1 in developing human bone and cartilage.

1994 ◽  
Vol 42 (6) ◽  
pp. 733-744 ◽  
Author(s):  
R A Dodds ◽  
K Merry ◽  
A Littlewood ◽  
M Gowen
Keyword(s):  
Mrna Expression ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Close Association ◽  
Interleukin 1 ◽  
Cell Types ◽  
Tgf Beta ◽  
Specific Stage ◽  
Growth Factor Beta

Using in situ hybridization, we investigated the expression of mRNA for interleukin-1 beta (IL1 beta), interleukin-6 (IL6), and transforming growth factor-beta-1 (TGF beta 1) in sections of developing bone in human osteophytes. The expression was related to the cellular activity of alkaline phosphatase to aid in the identification of pre-osteoblast populations. IL1 beta mRNA was localized in active osteoblasts within distinct areas of intramembranous ossification. However, the expression was sporadic and appeared to occur at a specific stage of the osteoblast life cycle. There was no IL1 beta mRNA expression in any cell types during endochondral ossification. IL6 mRNA expression was located within pre-osteoblasts and in newly differentiated and matrix-secreting osteoblasts; expression was absent or reduced in flattened, inactive osteoblasts. Weak or no IL6 expression was observed in chondroblasts and chondrocytes, respectively. However, there was a close association between IL6 mRNA expression and the differentiation of mesenchymal cells into osteoblasts. TGF beta 1 expression was localized to osteoblasts apposed to bone or cartilage matrix; the intensity of expression correlated with matrix secretion. Chondroblasts and chondrocytes expressed lower but significant levels of TGF beta 1 mRNA; the expression was lost with the progression to calcifying cartilage. The three cytokines studied were differentially expressed both temporally and spatially, suggesting different roles for each in osteoblast and chondrocyte function.

scholarly journals Synthesis of transforming growth factor-beta 1 by megakaryocytes and its localization to megakaryocyte and platelet alpha-granules

Blood ◽  
1990 ◽  
Vol 76 (10) ◽  
pp. 1946-1955 ◽  
Author(s):  
RA Fava ◽  
TT Casey ◽  
J Wilcox ◽  
RW Pelton ◽  
HL Moses ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Messenger Rna ◽  
Transforming Growth Factor ◽  
Immunoperoxidase Technique ◽  
Storage Site ◽  
Tgf Beta ◽  
Growth Factor Beta

We have directly demonstrated that megakaryocytes are a major site of synthesis and storage of transforming growth factor-beta 1 (TGF/beta 1) by combined immunohistochemical, immunocytochemical, and in situ hybridization methods. The presence of TGF/beta 1 messenger RNA (mRNA) in mature megakaryocytes in adult rat spleen and bone marrow (BM) was established by in situ hybridization. Localization of TGF/beta 1 protein to intact alpha-granules of megakaryocytes, its putative storage site, was accomplished in glycol-methacrylate embedded porcine BM with an immunoperoxidase technique and light microscopy. The TGF/beta 1 was sequestered in intracytoplasmic granules in a pattern virtually identical to that of another alpha-granule marker protein, fibrinogen. This observation strongly suggests packaging of TGF/beta 1 into this organelle within megakaryocytes. That TGF/beta 1 mRNA was localized to megakaryocytes suggests that the TGF/beta 1 found in the alpha-granules in platelets originates with megakaryocyte synthesis. The alpha-granule localization of TGF/beta 1, as well as fibrinogen, was also demonstrated in isolated platelets at the ultrastructural level by electronmicroscopy (EM) and postembedding colloidal-gold immunocytochemistry, thus directly demonstrating that alpha-granules are the final storage site for TGF/beta 1 in mature platelets.

In-situ measurement of the current transformer burden in a current transformer testing system using a shunt resistor

Measurement ◽  
2007 ◽  
Vol 40 (9-10) ◽  
pp. 876-882 ◽  
Author(s):  
Jae Kap Jung ◽  
Jeon Hong Kang ◽  
Sang Hwa Lee ◽  
Myungsoo Kim
Keyword(s):  
Current Transformer ◽  
In Situ Measurement ◽  
Testing System ◽  
A Current

Electromigration of Electroplated Gold Interconnects

2005 ◽  
Vol 863 ◽  
Author(s):  
Steve Kilgore ◽  
Craig Gaw ◽  
Haldane Henry ◽  
Darrell Hill ◽  
Dieter Schroder
Keyword(s):  
Activation Energy ◽  
Diffusion Mechanism ◽  
Time To Failure ◽  
Ambient Temperatures ◽  
Temperature Coefficients ◽  
Current Stressing ◽  
Monitoring Technique ◽  
The Times ◽  
A Current

AbstractElectromigration tests were performed on passivated electroplated Au four terminal Kelvin line structures using the conventional in situ resistance monitoring technique. The stress conditions were a current density of 2.0 MA/cm2 with ambient temperatures ranging from 325°C to 375°C. The temperature coefficients of resistance (TCR) values were measured prior to current stressing to calculate the Joule heated film temperatures. The times to failure (lifetimes) for the Au line structures were considered as a 50% ΔR/R0 change. The median time to failure (t50%) was plotted against the inverse film temperature to determine the activation energy value as 0.59 ± 0.09 eV. Failure analysis of void location and suggested diffusion mechanism will be discussed.

Developmental expression of transforming growth factors alpha and beta in mouse fetus

1988 ◽  
Vol 8 (8) ◽  
pp. 3415-3422
Author(s):  
J N Wilcox ◽  
R Derynck
Keyword(s):  
Transforming Growth Factor ◽  
Developmental Expression ◽  
Otic Vesicle ◽  
Tgf Beta ◽  
Hematopoietic Organ ◽  
Mouse Fetus ◽  
Branchial Arches ◽  
Factor Alpha ◽  
And Function

Expression of mRNA for transforming growth factor alpha (TGF-alpha) and TGF-beta 1 during the fetal development of mice was evaluated by in situ hybridization. TGF-alpha mRNA was detected in 9- and 10-day fetuses but was absent in older fetuses. TGF-alpha mRNA-containing cells were found in the placenta, otic vesicle, oral cavity, pharyngeal pouch, first and second branchial arches, and developing kidneys. mRNA for TGF-beta 1 was present in hematopoietic cells of blood islands and capillaries and in the liver as it began to bud off on day 10 and function as a hematopoietic organ.

In situ hybridization analysis of TGF beta 3 RNA expression during mouse development: comparative studies with TGF beta 1 and beta 2

Development ◽  
1990 ◽  
Vol 110 (2) ◽  
pp. 609-620 ◽  
Author(s):  
R.W. Pelton ◽  
M.E. Dickinson ◽  
H.L. Moses ◽  
B.L. Hogan
Keyword(s):  
Intervertebral Discs ◽  
The Other ◽  
Rna Expression ◽  
Tgf Beta ◽  
Mouse Development ◽  
Olfactory Bulbs ◽  
Embryonic Tissues ◽  
Organ Systems ◽  
Beta 2

To date, three closely-related TGF beta genes have been found in the mouse; TGF beta 1, TGF beta 2 and TGF beta 3. Previous experiments have indicated that TGF beta 1 and TGF beta 2 may play important roles during mouse embryogenesis. The present study now reports the distribution of transcripts of TGF beta 3 in comparison to the other two genes and reveals overlapping but distinct patterns of RNA expression. TGF beta 3 RNA is expressed in a diverse array of tissues including perichondrium, bone, intervertebral discs, mesenteries, pleura, heart, lung, palate, and amnion, as well as in central nervous system (CNS) structures such as the meninges, choroid plexus and the olfactory bulbs. Furthermore, in several organ systems, TGF beta 3 transcripts are expressed during periods of active morphogenesis suggesting that the protein may be an important factor for the growth and differentiation of many embryonic tissues.

Regulated expression and growth inhibitory effects of transforming growth factor-beta isoforms in mouse mammary gland development

Development ◽  
1991 ◽  
Vol 113 (3) ◽  
pp. 867-878 ◽  
Author(s):  
S.D. Robinson ◽  
G.B. Silberstein ◽  
A.B. Roberts ◽  
K.C. Flanders ◽  
C.W. Daniel
Keyword(s):  
Gene Expression ◽  
Mammary Gland ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Slow Release ◽  
Mouse Mammary Gland ◽  
Tgf Beta ◽  
Growth Factor Beta ◽  
Beta 2

Transforming Growth Factor-beta 1 (TGF-beta 1) was previously shown to inhibit reversibly the growth of mouse mammary ducts when administered in vivo by miniature slow-release plastic implants. We now report a comparative analysis of three TGF-beta isoforms with respect to gene expression and localization of protein products within the mouse mammary gland. Our studies revealed overlapping expression patterns of TGF-beta 1, TGF-beta 2 and TGF-beta 3 within the epithelium of the actively-growing mammary end buds during branching morphogenesis, as well as within the epithelium of growth-quiescent ducts. However, TGF-beta 3 was the only isoform detected in myoepithelial progenitor cells (cap cells) of the growing end buds and myoepithelial cells of the mature ducts. During pregnancy, TGF-beta 2 and TGF-beta 3 transcripts increased to high levels, in contrast to TGF-beta 1 transcripts which were moderately abundant; TGF-beta 2 was significantly transcribed only during pregnancy. Molecular hybridization in situ revealed overlapping patterns of expression for the three TGF-beta isoforms during alveolar morphogenesis, but showed that, in contrast to the patterns of TGF-beta 1 and TGF-beta 2 expression, TGF-beta 3 is expressed more heavily in ducts than in alveoli during pregnancy. Developing alveolar tissue and its associated ducts displayed striking TGF-beta 3 immunoreactivity which was greatly reduced during lactation. All three isoforms showed dramatically reduced expression in lactating tissue. The biological effects of active, exogenous TGF-beta 2 and TGF-beta 3 were tested with slow-release plastic implants. These isoforms, like TGF-beta 1, inhibited mammary ductal elongation in situ by causing the disappearance of the proliferating stem cell layer (cap cells) and rapid involution of ductal end buds. None of the isoforms were active in inhibiting alveolar morphogenesis. We conclude that under the limited conditions of these tests, the three mammalian isoforms are functionally equivalent. However, striking differences in patterns of gene expression and in the distribution of immunoreactive peptides suggest that TGF-beta isoforms may have distinct roles in mammary growth regulation, morphogenesis and functional differentiation.

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