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J Rasmussen

Publications and source records attributed to J Rasmussen.

At least 55 records · Page 3Linked to original sources
PubMed1989

A NADH dehydrogenase subunit gene is co-transcribed with the abnormal Petunia mitochondrial gene associated with cytoplasmic male sterility.

DNA sequence analysis 3' to the Petunia S-pcf coding region has resulted in the identification of an open reading frame similar to mammalian mitochondrial genes for subunit 3 of the NADH dehydrogenase complex (nad3). Both the abnormal fused gene S-pcf and S-nad3 fall within the mitochondrial DNA region previously shown to be associated with cytoplasmic male sterility (CMS). The S-nad3 sequence, co-transcribed with S-pcf, is present in only one copy within the Petunia CMS genome. A homologous transcribed sequence from the mitochondrial genome of a fertile Petunia line has been identified. The coding region of the two genes are identical and they share homology for at least 800 bp downstream. The genes diverge 117 bp upstream of the nad3 start codon. Transcripts of the S-pcf/S-nad3 transcripts are similar in tissues of a fertility-restored line and a CMS line.

Amino Acid Sequence↗
PubMed1989

Correlation of exposure time, concentration and incorporation of IdUrd in V-79 cells with radiation response.

These experiments were designed to find the minimum concentration at which incorporation of and sensitization by IdUrd (Iododeoxyuridine) would occur and the effect of concentrations from .1 to 100 microM for exposures of 8 to 96 hr in cultured V-79 cells exposed to 137Cs gamma rays at 2 Gy per minute. At 0.1 microM thymidine replacement averaged 1% and the SER ranged from 1.1 to 1.28, significant at the 95% level. The maximum thymidine replacement was 49% after 48 hr exposure to 30 microM yielding an SER of 2.7. SER generally peaked after 72 hr of exposure. This cell line has an 8 hr cycle time in our hands and thus optimal sensitization would occur after 9 cell cycles. These ranges need testing in human cells in culture and in Phase I clinical trials.

Animals↗
PubMed1988

Detection of styrene oxide-DNA adducts by 32P-postlabeling.

In vitro reaction of DNA with styrene-7,8-oxide (styrene oxide) produced five adducts, as determined by 32P-postlabeling. When styrene oxide was reacted in vitro with deoxyribonucleotides, five adducts were observed from 2'-deoxyguanosine-3'-monophosphate, two from 2'-deoxyadenosine-3'-monophosphate, none from 2'-deoxythymidine-3-monophosphate or 2'-deoxycytidine-3'-monophosphate. Chromatographic comparison of the adducts formed in DNA with those formed with the deoxyribonucleotides suggests that deoxyguanosine is the primary site of DNA modification. Treatment of 9L cells with 1 mM styrene oxide resulted in the formation of several DNA adducts as detected by the postlabeling procedure. Our results indicate that 32P-postlabeling can be used to investigate DNA adducts formed by styrene oxide.

DNA↗
PubMed1988

Immunohistochemical steroid receptor detection in frozen breast cancer tissue. A multicenter investigation.

Now that monoclonal antibodies against the estrogen receptor (ER) have become available, it is possible to detect the presence of ER immunohistochemically. In order to evaluate the validity of the immunohistochemical (ERICA) method in a routine detection of ER, we have tested the method in a multicenter investigation. As reference is used a conventional biochemical assay, dextran-coated-charcoal assay (DCC). The investigation analyzes the validity of the ERICA-assay, including a semiquantitative estimation of the ER-content, when the method is used in several independent departments of pathology, and the interobserver variation of the analysis. The results show that the qualitative detection of ER, obtained by the ERICA-assay and the DCC-assay has a concordance of about 90% for all the participating departments. The concordance is around 60-70%, when a semiquantitative estimation of the ER-content is used. The interobserver variation is also very low, with full agreement in 58 of 59 cases. The ERICA-assay may, therefore, be a relevant alternative to the DCC-assay. However, its clinical importance still has to be fully elucidated.

Antibodies, Monoclonal↗
PubMed1987

A vesicular intermediate in the transport of hepatoma secretory proteins from the rough endoplasmic reticulum to the Golgi complex.

We have identified a vesicle fraction that contains alpha 1-antitrypsin and other human HepG2 hepatoma secretory proteins en route from the rough endoplasmic reticulum (RER) to the cis face of the Golgi complex. [35S]Methionine pulse-labeled cells were chased for various periods of time, and then a postnuclear supernatant fraction was resolved on a shallow sucrose-D2O gradient. This intermediate fraction has a density lighter than RER or Golgi vesicles. Most alpha 1-antitrypsin in this fraction (P1) bears N-linked oligosaccharides of composition similar to that of alpha 1-antitrypsin within the RER; mainly Man8GlcNac2 with lesser amounts of Man7GlcNac2 and Man9GlcNac2; this suggests that the protein has not yet reacted with alpha-mannosidase-I on the cis face of the Golgi complex. This light vesicle species is the first post-ER fraction to be filled by labeled alpha 1-antitrypsin after a short chase, and newly made secretory proteins enter this compartment in proportion to their rate of exit from the RER and their rate of secretion from the cells: alpha 1-antitrypsin and albumin faster than preC3 and alpha 1-antichymotrypsin, faster, in turn, then transferrin. Deoxynojirimycin, a drug that blocks removal of glucose residues from alpha 1-antitrypsin in the RER and blocks its intracellular maturation, also blocks its appearance in this intermediate compartment. Upon further chase of the cells, we detect sequential maturation of alpha 1-antitrypsin to two other intracellular forms: first, P2, a form that has the same gel mobility as P1 but that bears an endoglycosidase H-resistant oligosaccharide and is found in a compartment--probably the medial Golgi complex--of density higher than that of the intermediate that contains P1; and second, the mature sialylated form of alpha 1-antitrypsin.

1-Deoxynojirimycin↗
PubMed1987

Bone regeneration under the influence of a bone morphogenetic protein (BMP) beta tricalcium phosphate (TCP) composite in skull trephine defects in dogs.

Beta tricalcium phosphate (TCP) was employed as a nonimmunogenic biodegradable delivery system for bovine bone morphogenetic protein (BMP). A BMP/TCP composite was implanted in adult dogs with skull trephine defects of a critical size of 1.4 cm that would otherwise remain unhealed in the lifetime of the individual. BMP/TCP implants induced 91%-100% incorporation by deposits of new bone. In comparison, control implants of TCP impregnated with bovine serum albumin (BSA/TCP) induced 0%-8% incorporation, or only marginal host bed reactive bone formation. The retention of unabsorbed TCP in the host bone four months after implantation suggests that further research should be encouraged to obtain a formulation of sintered calcium phosphate that could be resorbed more rapidly and in the process more completely replaced by bone.

Animals↗
PubMed1986

Interleukin-2-induced chemotaxis of human T-lymphocytes.

Interleukin-2 (IL-2), a growth factor for T-lymphocytes, has been postulated to cause the accumulation of T-lymphocytes at sites of inflammation by inducing proliferation of these cells. We hypothesized that IL-2 might also serve to attract T-lymphocytes to inflammatory sites. To test this hypothesis, human T-lymphocytes were purified from the peripheral blood of normal volunteers by rosetting with neuraminidase-treated sheep red blood cells and tested for chemotactic activity by using a blind-well chamber technique. Purified IL-2 caused a greater than 20-fold attraction of T-lymphocytes compared with medium alone (P less than 0.001). This attraction was shown to be chemotactic rather than chemokinetic by checkerboard analysis. The T-lymphocyte chemotaxis could be completely inhibited by adsorption of the IL-2 with an IL-2-dependent cell line, and could be neutralized by monoclonal anti-IL-2 antibody. Further specificity of IL-2-directed chemotaxis was demonstrated by using species-specific IL-2. Mouse IL-2 was ineffective at promoting human T-lymphocyte chemotaxis. These data suggest that IL-2 may be responsible for the localized accumulation of T-lymphocytes both by causing attraction of these cells and by modulating their proliferation.

Animals↗
PubMed1985

Potentiation of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU)-induced cytotoxicity in 9L cells by pretreatment with 6-thioguanine.

9L Rat brain tumor cells were treated with 0.2 microM 6-thioguanine for 48 hr, which produced a 40% cell kill, a small (15%) inhibition of cell growth, and an accumulation of cells in S-phase. Maximum incorporation of [14C]6-thioguanine into cellular DNA occurred after 24 hr of incubation; 70% of the label was incorporated into DNA as 6-thio-2'-deoxyguanosine. Pretreatment of 9L cells for 48 hr with 0.2 microM 6-thioguanine potentiated the cytotoxicity of 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU) by 50% with a dose enhancement ratio of 1.5, and caused a 30% increase in the number of BCNU-induced sister chromatid exchanges (SCEs) and a 50% increase in DNA crosslinks formed, compared to treatment with BCNU alone. Used as a single agent, 6-thioguanine induced a significant number of SCEs. Results suggest that these effects may be related to the increased formation of DNA crosslinks, possibly as the result of the formation of S6-(2-chloroethyl)-6-thioguanine in cellular DNA.

Animals↗
PubMed1985

Comparison of sister-chromatid exchange induction caused by nitrosoureas that alkylate or alkylate and crosslink DNA.

We have investigated the induction of sister-chromatid exchanges (SCEs) in 9L rat brain tumor cells treated with the alkylating agent 1-ethyl-1-nitrosourea (ENU) and 3-(4-amino-2-methyl-5-pyrimidinyl)methyl-1-(2-chloroethyl)-1-nitrosourea (ACNU), an agent that both alkylates and crosslinks DNA. Induction of SCEs by ACNU was found to be 143-fold greater than for ENU. However, on an equimolar basis, the alkylation of DNA by 14C-ACNU was approximately 3.2-fold higher than for 14C-ENU. After correction for this difference was made, the induction of SCEs by ACNU was calculated to be 45-fold greater than for ENU. While DNA alkylation products formed by ACNU and ENU are similar, the chloroethyl alkylation product(s) of ACNU can form DNA-interstrand crosslinks; the ethyl alkylation product(s) of ENU cannot. Based on these findings, we propose that the increased induction of SCEs caused by ACNU is a result of the formation of DNA interstrand crosslinks.

Alkylating Agents↗
PubMed1985

Recurrent photosensitive dermatitis preceding juvenile dermatomyositis.

The classic features of childhood dermatomyositis include muscle weakness, elevated muscle enzymes, and characteristic abnormal muscle biopsy and electromyography. Paramount to the diagnosis are cutaneous dermatoses that include a heliotrope rash and Gottron's papules. Rarely, a photo-sensitive dermatosis may occur. A recurrent photoexacerbated dermatoses can be an initial sign of occult childhood dermatomyositis.

Adrenal Cortex Hormones↗
PubMed1985

Immunologic evidence of a bone morphogenetic protein in the milieu intérieur.

Eighteen different groups of proteins have been identified in the organic matrix of bone. To date, seven have been identified in circulating blood. Several plasma proteins are found to accumulate in bone matrix. Two bone, carboxyglutamic acid rich proteins (BGP or osteocalcin) and bone morphogenetic protein (BMP) are measured by RIA in serum in the range of ng/ml. Of all matrix groups, the least abundant is BMP. Acting as a paracrine or local hormone, BMP induces perivascular connective tissue cells of bone marrow to differentiate into cartilage and bone. Neither the mechanism of action or target cells, nor the mode of transport of BMP in serum are known, but the immunologic activity demonstrates higher serum BMP RIA levels in growing children and patients with Paget's Disease than in normal adults. Serum BMP is remarkably low in postmenopausal women with severe osteoporosis; serum anti-BMP antibody is correspondingly high. Although these observations are preliminary and based on a relatively small number of patients, the data suggest a working hypothesis that BMP and anti-BMP are bone tissue-specific parameters of normal and pathological bone physiology. The possibility of diagnosis of osteoporosis in the prefracture stage, and the prospects of evidence of an autoimmune response to the products of bone resorption, derived from the serum BMP anti-BMP ratio, warrant special investigation.

Adult↗
PubMed1984

A 32P postlabeling assay for determining the incorporation of bromodeoxyuridine into cellular DNA.

Randerath's procedure for 32P postlabeling of 3'-monophosphate deoxyribonucleotides from digests of cellular DNA has been modified. 3'-Monophosphate deoxyribonucleotides are converted to 3',5'-bis[32P]phosphate deoxyribonucleotides with polynucleotide kinase and [32P]ATP; these products are enzymatically converted by P1 nuclease and polynucleotide kinase into 5'-[32P]monophosphate deoxyribonucleotides, which are separated from [32P]ATP on an anion-exchange column eluted with 0.1 M NaH2PO4, pH 6.5. Labeled mononucleotides in the effluent are separated by high-performance liquid chromatography. Values for the base composition of calf thymus DNA determined with this modified assay compare very favorably with reported values. The assay was used to measure the level of incorporation of the clinically useful agent bromodeoxyuridine into the DNA of 9L rat brain tumor cells. The modified assay appears to be a very accurate method for the determination of levels of base analogs incorporated into DNA.

Animals↗
PubMed1984

Reduced level of DNA cross-links and sister chromatid exchanges in 1,3-bis(2-chloroethyl)-1-nitrosourea-resistant rat brain tumor cells.

We found that 9L-2 cells, a cell line derived from the in vivo 9L rat brain tumor model, are approximately 8-fold more resistant to the cytotoxic effect of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) than are sensitive 9L cells. Treatment with BCNU induces sister chromatid exchanges in both lines, but to produce similar levels of exchanges, 9L-2 cells must be treated with a 14-fold higher concentration of BCNU. The extent of DNA methylation was the same in both cell lines after a 1-hr treatment with 100 microM methylnitrosourea. While the levels of the alkylation products N-7-methylguanine and N-3-methyladenine were similar in both lines, the level of O6-methylguanine was 20% lower in 9L-2 than in 9L cells, which implies that 9L-2 cells repair O6-alkylguanine derivatives more efficiently than do 9L cells. The number of DNA interstrand cross-links formed in 9L-2 cells after treatment with BCNU was approximately 50% of the number formed in 9L cells. These results suggest that the repair of O6-alkylguanine derivatives formed in BCNU-treated 9L-2 cells may be related to the reduced number of DNA interstrand cross-links formed and may have a role in the mechanism of cellular resistance of 9L-2 cells to BCNU. However, our results indicate that, in itself, the reduction in the number of DNA cross-links may not be sufficient to account entirely for the cellular resistance of 9L-2 cells to BCNU and suggest that additional mechanisms may be involved in cellular resistance of 9L-2 cells to BCNU treatment.

Alkylation↗