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J Welsh

Publications and source records attributed to J Welsh.

At least 55 records · Page 3Linked to original sources
PubMed1998

Solitary plasmacytoma of the epiglottis: a case report and review of the literature.

A 59-year-old white male presented with a two-month history of dry cough and shortness of breath. At bronchoscopy, a 1 cm mass on the laryngeal surface of the epiglottis was found. Immunohistochemical stain of the biopsy specimen revealed a monoclonal proliferation of plasma cells. Serological tests revealed normal serum immunoglobulin levels, and a bone marrow aspirate and biopsy was also normal; no abnormalities were found on serum or urine electrophoresis. He received radiotherapy (50 Gy), and was doing well three years following therapy without evidence of disease.

Epiglottis↗
PubMed1998

Estrogen-responsive RING finger mRNA induction in gastrointestinal carcinoma cells following bile acid treatment.

The underlying molecular mechanisms of the tumor-promoting activity of bile acids such as chenodeoxycholic acid (CDCA) and deoxycholic acid (DCA) and the protective effect of ursodeoxycholic acid (UDCA) remain largely unclear. Using RNA arbitrarily primed PCR (RAP-PCR) for differential display, we identified, cloned and sequenced differentially expressed transcripts after treating gastric carcinoma cells (St 23132) with the bile acids CDCA, DCA and UDCA. One of these transcripts was identified to be an estrogen-responsive RING finger protein (efp) mRNA. The differential expression of efp in gastric cancer cells was confirmed by low stringency RT-PCR. efp mRNA levels were induced 3-fold in gastric carcinoma cells after CDCA and DCA treatment, whereas no change in expression was detected after UDCA treatment. Finally, treatment of the colon carcinoma cell line HT 29 with DCA resulted in a 2- to 5-fold induction of efp mRNA levels whereas UDCA did not induce efp. As expected, efp expression was also increased after 24 h of estrogen treatment. In summary, a synergy or a common pathway of tumor enhancement of bile acids and estrogen via efp in gastrointestinal carcinogenesis can be envisioned.

Bile Acids and Salts↗
PubMed1998

Copper efflux from murine microvascular cells requires expression of the menkes disease Cu-ATPase.

Previously, we showed that the transport of Cu by PC12 pheochromocytoma cells and C6 glioma cells correlated with the expression of a Cu-transporting ATPase (Atp7a) that has been linked to Menkes disease. Here, we show that cerebrovascular endothelial (CVE) cells that comprise the blood-brain barrier (BBB) also express the gene for the Cu-ATPase. By using reverse transcription-polymerase chain reaction (RT-PCR) and primers designed from mouse Atp7a cDNA, we amplified a 925-bp and a 760-bp cDNA fragment from two extreme regions of Atp7a mRNA from murine CVE cells; 777 bp of the 925-bp fragment and 677 bp of the 760-bp fragment had a 99.7 and 100% sequence homology, respectively, with mouse Atp7a cDNA. The 777-bp sequences covered the heavy metal binding (Hmb) domain and the 677-bp fragment coded for residues at the -COOH terminus of Atp7a. A functional analysis showed that Cu efflux was blocked by the sulfhydryl reagent p-chloromercuribenzoate (p-CMB), a potential inhibitor of Atp7a function. This study provides strong evidence that a Cu-ATPase in the BBB controls the penetration of Cu into the brain and that lesions to the Cu-ATPase in CVE cells are a primary cause of low brain Cu levels in Menkes disease.

Adenosine Triphosphatases↗
PubMed1998

Apoptotic regression of MCF-7 xenografts in nude mice treated with the vitamin D3 analog, EB1089.

1,25-Dihydroxyvitamin D3 [1,25-(OH)2D3] and its synthetic analog EB1089 induce characteristic morphological features of apoptosis in MCF-7 cells in vitro that coincide with up-regulation of clusterin and cathepsin B, proteins associated with apoptosis in the mammary gland, and with down-regulation of Bcl-2, an antiapoptotic protein. To determine whether vitamin D3 compounds could mediate apoptosis of breast tumors in vivo, we treated nude mice carrying established MCF-7 xenografts with the low calcemic vitamin D3 analog EB1089 via daily injection or sustained release pellets for up to 5 weeks. The volume of tumors from mice treated with 45 pmol/day EB1089 was 4-fold lower than that of tumors from vehicle-treated control mice after 5 weeks. The reduced growth of tumors from EB1089-treated mice was associated with characteristic apoptotic morphology and a marked reduction in the proportion of epithelial cells to stroma. After 5 weeks of treatment with EB1089, MCF-7 tumors exhibited a 6-fold increase in DNA fragmentation (as measured by in situ end labeling) relative to that in control tumors. The enhanced rate of apoptosis in tumors from EB1089-treated mice was coupled to a 2-fold reduction in proliferation (as measured by expression of proliferating cell nuclear antigen) compared with that in tumors from control mice. The antitumor effects of EB1089 were evident at doses that had minimal effects on serum calcium and body weight. EB1089 treatment did not alter the growth of xenografts derived from a vitamin D3-resistant variant of MCF-7 cells (MCF-7(D3Res) cells), which display resistance to EB1089 in vitro, indicating that resistance to EB1089 is maintained in vivo. Tumors derived from both MCF-7 and MCF-7(D3Res) cells underwent apoptotic regression upon estradiol withdrawal, indicating comparable estrogen dependence of tumors with differential sensitivity to vitamin D3 compounds. These are the first studies to demonstrate apoptotic morphology and regression of human breast tumors in response to treatment with a vitamin D3 analog in vivo and support the concept that vitamin D3 compounds can effectively target human breast cancer.

Animals↗
PubMed1998

GeneUp: a program to select short PCR primer pairs that occur in multiple members of sequence lists.

A computer program is presented that selects a small set of short primer pairs for PCR to sample all the sequences in a user-specified list of mRNAs. Such primer pairs could be used to increase the probability of sampling mRNAs of particular interest in differential display and to generate simplified hybridization probes for DNA chips or arrays. The program uses simulated PCR to find pairs of primers that sample more than one sequence in the list. A small set of such primer pairs is selected that give maximal coverage of the sequences in the list. Primer pairs are excluded that: (i) generate simulated PCR products of the same size from a number of sequences in the list, (ii) can easily form primer dimers, (iii) are outside a specified range of G + C content or (iv) occur in another list of undesirable sequences, such as rRNAs and Alu repeats. Five lists consisting of from 48-285 cDNA sequences were used to test the program. A small number of pairs of primers, 8-10 bases in length, were selected that fit the above criteria and that generate one or more simulated PCR products in all or most of the cDNAs in each list.

Base Sequence↗
PubMed1998

Freedom of Expression and the Healthy Society.

The links between freedom of expression and the health and well-being of the individual and of society seem readily apparent even if their full ramifications are not immediately clear. Health and health care are dependent on information, and the free exchange of this information is at the base of effective health protection and promotion. Equally, it is clear that such a widely-based concept as health intersects with, and is dependent on, a range of basic human needs. This article examines the links between provision of health care and the right of freedom of expression as set out in Article 19 of the Universal Declaration of Human Rights. It argues that both freedom of expression and commitment to health care are vital objectives but insufficient in and of themselves to realise a wider goal of human well-being. This article draws on examples from inner urban deprivation, women's health and HIV/AIDS to illustrate some of the factors and issues involved.

Journal Article↗
PubMed1998

Overexpression of Lerk-5/Eplg5 messenger RNA: a novel marker for increased tumorigenicity and metastatic potential in human malignant melanomas.

The Lerks, ligands of eph-related receptor tyrosine kinases, are a rapidly expanding family of genes thought to play an important role in the development and oncogenesis of various tissues. However, very little experimental evidence supports this hypothesis. Using RNA fingerprinting, we detected increased expression of Lerk-5 mRNA in human melanocytes as a response to the tumor-promoting drug 12-O-tetradecanoylphorbol-13-acetate, which suggests a possible role of the Lerks in melanoma tumorigenesis and progression. Therefore, we studied Lerk-5 mRNA expression in various melanoma cell lines and tissues of melanocytic tumors by semiquantitative reverse transcription-PCR. Modest expression of Lerk-5 mRNA was found in two melanoma cell lines derived from early primary tumors (WM35 and WM1645B); two metastatic cell lines tested showed a 3.9-fold increased transcript abundance when compared to the primary cell lines (RPMI-7951 and SK-Mel5). Progeny of a melanoma cell line with very low Lerk-5 mRNA abundance (WM35) showed a 5-fold increase in Lerk-5 mRNA expression when it was selected for higher tumorigenicity and multicytokine resistance by passaging in nude mice or repeated high-dose UVB irradiation. Consistent with these experimental data, we found high levels of Lerk-5 mRNA expression in advanced primary malignant melanomas and metastases (n = 22) but significantly lower or undetectable mRNA expression in benign melanocytic nevi (n = 9; P < 0.001). We conclude that increased Lerk-5 expression possibly reflects or induces an increased potential of growth, tumorigenicity, and metastatic abilities in human melanomas. This makes the yet to be elucidated eph-related receptor tyrosine kinase/Lerk signaling system a potential new source for molecular markers as well as a target for new therapies.

Animals↗
PubMed1998

Dissociation of vitamin D3 and anti-estrogen mediated growth regulation in MCF-7 breast cancer cells.

Our studies have identified 1,25(OH)2D3 as a coordinate regulator of proliferation and apoptosis in breast cancer cells. In MCF-7 cells, 1,25(OH)2D3 down regulates the estrogen receptor (ER), suggesting that the effects of 1,25(OH)2D3 may be linked to disruption of estrogen regulated survival signals. Although studies have demonstrated that 1,25(OH)2D3 inhibits growth of ER negative breast cancer cells, previous data were generated by comparison of cell lines derived from heterogeneous human tumors and harboring diverse genetic alterations. To provide more conclusive evidence for independent growth regulatory pathways mediated by antiestrogens and 1,25(OH)2D3, we examined vitamin D3 sensitivity in MCf-7 cells selected for resistance to ICI 182, 780 (Zeneca, Macclesfield, UK). The clones we selected for resistance to ICI 182,780 retain functional VDR and undergo 1,25(OH)2D3 mediated growth arrest and apoptosis, in vitro and in vivo, despite loss of estrogen dependence. Cell cycle data indicate that treatment of parental or anti-estrogen resistant MCF-7 clones with 1,25(OH)2D3, in the presence or absence of ICI 182,780, increases the percentage of cells in G0/G1 while reducing the number of cells in S phase. In addition, 1,25(OH)2D3 induces characteristic features of apoptosis, including DNA fragmentation, in both parental and anti-estrogen resistant MCF-7 cells. Furthermore, we report that cells selected for vitamin D3 resistance retain sensitivity to ICI 182,780 mediated growth arrest and apoptosis. This work emphasizes that vitamin D3 compounds and anti-estrogens trigger growth arrest and apoptosis in breast cancer cells by distinct mechanisms, and that breast cancer cell sensitivity to 1,25(OH)2D3 is not diminished during the progression to estrogen independence.

Apoptosis↗
PubMed1997

Nurses at risk.

Explore the source record for details and available documents.

Female↗
PubMed1997

RNA fingerprinting displays UVB-specific disruption of transcriptional control in human melanocytes.

In mammalian cells, UV induces a limited set of early transcribed genes, which overlaps with the set of genes induced by tumor promoting drugs such as 12-O-tetradecanoyl phorbol-13-acetate (TPA). Among these are genes for transcription factors, the activation of which leads to complex secondary changes in expression of multiple target genes. How these delayed pleiotropic UV effects on transcription may contribute to initiation of melanoma skin cancer is poorly understood. We analyzed changes in the relative abundances of 1900 transcripts in newborn human melanocytes 8 h after treatment with UVB, TPA, and cycloheximide in all combinations, using RNA arbitrarily primed PCR for differential display. The relative abundances of 205 transcripts (11% of all transcripts surveyed) were altered by one or more of the treatment combinations. Fourteen of the 77 genes up-regulated by TPA were also up-regulated by UVB, but 60 of the TPA up-regulated genes were down-regulated by UVB, indicating both intersecting and independent signal transduction pathways for UVB and TPA. A number of UVB and TPA target genes were identified by cDNA cloning. Consistent with UVB induction of a partly transformed phenotype in mammalian cells, UVB antagonized the TPA-inducible expression of tumor-suppressive tropomyosin 3 mRNA. In addition, UVB may impair mitochondrial functioning and induce oxidative stress by strong down-regulation of mitochondrial transcription. Finally, increased expression of the dihydropteridine reductase gene, a major regulator of the cellular tetrahydrobiopterin pool, was linked to the UV pathway.

Carcinogens↗
PubMed1997

Comparative effects of 1,25(OH)2D3 and EB1089 on cell cycle kinetics and apoptosis in MCF-7 breast cancer cells.

1,25-dihydroxyvitamin D3 [1,25(OH)2D3], the active metabolite of vitamin D2 inhibits breast cancer cell growth both in vivo and in vitro. In addition to its anti-proliferative effects, 1,25(OH)2D3 induces morphological and biochemical markers of apoptosis in MCF-7 cells. In the studies reported here, we compared the effects of 1,25(OH)2D3 and EB1089, a low calcemic vitamin D analog, on cell cycle kinetics and apoptosis in MCF-7 cells. Both vitamin D compounds reduced viable MCF-7 cell number in a time and dose dependent manner, with EB1089 approximately 50 fold more potent than 1,25(OH)2D3. Flow cytometric analysis indicated that both agents induced cell cycle arrest in G, G1 which was associated with accumulation of the hypophosphorylated form of the retinoblastoma (Rb) protein. MCF-7 cells treated with either 1,25(OH)2D3 or EB1089 for 48 h exhibited characteristics of apoptosis, including cytoplasmic condensation, pyknotic nuclei, condensed chromatin and DNA fragmentation. Cells treated with either agent exhibited up regulation of proteins associated with mammary gland regression (clusterin and cathepsin B) and down regulation of the anti-apoptotic protein bcl-2. These studies demonstrate that, despite its lower calcemic activity in vivo, the vitamin D analog EB1089 induces effects that are indistinguishable from those of 1,25(OH)2D3 on cell number, cell cycle and indices of apoptosis in MCF-7 cells in vitro. In addition, since both agents rapidly down regulate estrogen receptor, disruption of estrogen dependent signalling may play a role in the induction of apoptosis by vitamin D compounds in MCF-7 cells.

Antineoplastic Agents↗
PubMed1997

Modulation and phosphorylation of calbindin-D28K correlates with protein kinase C activation1.

Calbindin-D28K is a vitamin D3 dependent calcium-binding protein expressed in renal distal tubules. We previously reported that 24 h treatment with 1 alpha, 25-dihydroxyvitamin D3 (1,25-D3), the active form of vitamin D3, induces calbindin-D28K and activates protein kinase C (PKC) in MDBK (Madin-Darby bovine kidney) cells. In contrast, 24 h treatment with the phorbol ester 12-O-tetradecanoylphorbol-3-acetate (TPA) downregulates calbindin-D28K and PKC activity. In the present studies, we demonstrate that TPA rapidly enhances calbindin-D28K expression in MDBK cells in the absence of 1,25-D3. The enhancement of calbindin-D28K expression is preceded by activation and translocation of PKC alpha. Further, we show that PKC directly phosphorylates calbindin-D28K in a calcium- and phospholipid-dependent manner in vitro. In MDBK cells, the calbindin-D28K antibody immunoprecipitates a 28 kDa protein for which phosphorylation is enhanced after treatment for 1 h with TPA or 24 h with 1,25-D3. Consistent with amino acid sequence analysis of calbindin-D28K indicating two threonine residues that fit the consensus for PKC phosphorylation, TPA-treated MDBK cells exhibit enhanced expression of a phosphothreonine-containing protein that co-migrates with calbindin-D28K. These studies offer the first report that calbindin-D28K is a phosphoprotein and implicate the PKC signal transduction pathway in its regulation.

Animals↗
PubMed1997

Differential effects of 1,25-dihydroxyvitamin D3 and tetradecanoylphorbol acetate on cell cycle and apoptosis of MCF-7 cells and a vitamin D3-resistant variant.

1,25-Dihydroxyvitamin D3 (1,25-(OH)2D3), the active form of vitamin D3, and tetradecanoylphorbol acetate (TPA) are potent negative growth regulators of breast cancer cells. In this study, we compared the mechanism of action of these two compounds in MCF-7 cells and a vitamin D3-resistant variant (MCF-7D3Res). In parental MCF-7 cells, 1,25-(OH)2D3 induced morphological and biochemical markers of apoptosis (chromatin and nuclear matrix condensation and DNA fragmentation), whereas TPA induced growth arrest without apoptosis. Both 1,25-(OH)2D3 and TPA independently up-regulated the vitamin D receptor, p21, and the hypophosphorylated form of retinoblastoma (Rb) protein. The growth regulatory effects of 1,25-(OH)2D3 and TPA did not correlate with induction of p53 protein expression. When both compounds were added simultaneously, synergistic effects on MCF-7 cell number were observed, and cell cycle regulatory proteins were down-regulated. The MCF-7D3Res cells, which are not sensitive to 1,25-(OH)2D3, were growth inhibited by TPA, and TPA partially sensitized MCF-7D3Res cells to the growth inhibitory effects of 1,25-(OH)2D3. In MCF-7D3Res cells, 1,25-(OH)2D3 treatment had minimal effects on p21 or Rb protein expression, whereas TPA down-regulated Rb protein and transiently up-regulated p21. These studies indicate dissociation between the pathways triggered by 1,25-(OH)2D3 and TPA, which mediate growth regulation in MCF-7 cells. Because both compounds induce growth arrest, but only 1,25-(OH)2D3 mediates apoptosis, we conclude that cell cycle arrest is not sufficient to trigger cell death of MCF-7 cells, and that 1,25-(OH)2D3 generates distinct signals which lead to induction of apoptosis in breast cancer cells.

Apoptosis↗