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B Allison

Publications and source records attributed to B Allison.

7 recordsLinked to original sources
PubMed1999

Transforming growth factor-beta differentially inhibits epithelial ovarian carcinoma cells from primary and metastatic isolates without up-regulation of p21WAF1.

BACKGROUND: Transforming growth factor-beta (TGF-beta) is known to inhibit primary epithelial ovarian carcinoma cells. The mechanism by which this inhibitory response is achieved is poorly understood. Furthermore, whether this response is consistent in cells from metastatic sites compared with the primary site cells is unknown. The authors wanted to determine whether TGF-beta differentially inhibited ovarian carcinoma cells from primary tumor sites compared with metastatic sites and to establish whether this response was associated with up-regulation of p21WAF1 or overexpression of p53. METHODS: Tumor cells were purified from primary and metastatic sites in five patients with advanced epithelial ovarian carcinoma. TGF-beta effect at concentrations of 10, 1, and 0.1 ng/mL was determined by tritiated thymidine incorporation assay. Expression of p21WAF1 was determined by Northern and slot blot analysis. p53 was detected by immunocytochemistry. RESULTS: Metastatic tumor isolates were more responsive to the inhibitory effect of TGF-beta compared with their corresponding primary tumor isolates at 0.1 ng/mL. Increasing TGF-beta concentration conferred no additional inhibitory effect on the metastatic isolates; however, a dose-related phenomenon was observed in primary tumor isolates. p21WAF1 mRNA was up-regulated in only 2 of 10 primary and metastatic isolates. There was no correlation between TGF-beta responsiveness, p21WAF1 up-regulation, and p53 overexpression. CONCLUSIONS: Differential inhibition was observed between primary and metastatic tumor isolates. p21WAF1 up-regulation and p53 overexpression were not major modulators in TGF-beta regulation of primary and metastatic tumor growth in early passaged ovarian carcinoma cells.

Carcinoma↗
PubMed1997

Collagenase expression in ovarian cancer cell lines.

BACKGROUND: There are several distinct forms of the matrix metalloproteinases (MMP) that degrade collagen in the extracellular matrix. Most involved in the metastatic process are collagenases exhibiting specificity for type IV collagen, the collagen that makes up the backbone of the basement membrane. We chose to examine the expression of one type IV collagenase, MMP-9, in several ovarian cancer cell lines. METHODS: Under the influence of phorbol esters such as TPA, the fibrosarcoma cell line HT1080 is known to express MMP-9. We examined the effect of TPA on MMP-9 expression with Northern analysis, and on MMP-9 collagenase activity with polyacrylamide gel electrophoresis-zymography, in HT1080 cells (positive control) and in six ovarian cancer cell lines: Hey, HeyA8, CAOV3, PA-1, SKOV3, and OVCAR3. Cells were grown to 70% confluence and the growth medium was changed to a serum-free medium for 24 hr. Cells were then treated with 12 ng/mL TPA or its vehicle for an additional 24 hr. Medium was collected for PAGE-zymographic analysis. The cells were lysed and their RNA collected for Northern analysis. RESULTS: PA-1, a teratocarcinoma, expressed more than 10-fold the amount of RNA for MMP-9 than the other lines following TPA treatment. Both Northern analysis and zymography showed that four of the six ovarian cell lines responded to TPA with increased collagenase expression and activity. The other two cell lines showed no MMP-9 activity either before or after TPA treatment. CONCLUSIONS: These results suggest that ovarian cancer cell lines express collagenase and that this expression may be regulated by phorbol esters which activate the protein kinase C pathway.

Base Sequence↗
PubMed1991

Photosensitising potency of structural analogues of benzoporphyrin derivative (BPD) in a mouse tumour model.

The in vivo characteristics of four analogues of benzoporphyrin derivative (BPD) have been investigated. Biodistribution data obtained in DBA/2J mice with BPD-MA (monoacid ring A analogue) which had been tritiated or internally labelled with 14C showed that both labelled materials acted in an essentially identical manner during the period of study. Biodistribution and clearance studies showed that relative distribution in a variety of mouse tissues was similar for all BPD analogues. M1 tumour cells (rhabdomyosarcoma in DBA/2J mice) taken from tumours excised from animals treated 3 h earlier with BPD, and tested in vitro for photosensitivity provided evidence that significant levels of photosensitiser detected in tumour was both active and associated with tumour cells. The monoacid forms of BPD were found to be much more photodynamically active in this test than were the diacid analogues. The ability of the analogues to ablate tumours in mice by photodynamic therapy was also tested. Again, BPD-MA and BPD-MB proved to be measurably better than the diacid analogues. These findings are discussed in reference to structural and physical differences between the analogues.

Animals↗
PubMed1983

Giardiasis: a common, sexually transmissible parasitic diarrhea with pitfalls in diagnosis.

Giardia lamblia is the number one intestinal parasite in the United States. Symptoms of giardiasis include upper abdominal pain and distress, flatulence, nervousness, and diarrhea. Multiple stool specimens examined for ova and parasites by nonexpert parasitologists will frequently not provide the diagnosis, and special studies must then be done. Antibiotics, antidiarrheals, certain enema preparations, and oily laxatives can cause a temporary disappearance of parasites from the stool. Treatment of choice is a five-day course of quinacrine hydrochloride. Recently, attention has been brought to the fact that oral sex may be responsible for transmission in a significant number of cases of giardiasis.

Child↗
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