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Biomedical subjects

G Stamp

Publications and source records attributed to G Stamp.

At least 19 recordsLinked to original sources
PubMed2007

Management and prevention of adverse effects related to treatment of liver tumours with 90Y microspheres.

BACKGROUND AND AIM: Selective internal radiation therapy with 90Y microspheres (SIR spheres) is increasingly used in the treatment of extensive liver tumours. Careful selection and preparation of patients are necessary to avoid possible adverse effects. We aimed to evaluate the incidence and severity of adverse effects resulting from the administration of SIR spheres during therapy. MATERIALS AND METHODS: Between June 2004 and August 2006, 21 patients (11 women and 10 men; age range 40-75 years; mean, 58 years) with a wide range of extensive liver tumours were treated with SIR spheres. The mean administered dose was 1.87 GBq (range 1.2-2.5 GBq). During the follow-up period of 26 months, all adverse effects were monitored and classified according to the National Cancer Institute criteria. RESULTS: Four patients had adverse effects: one case of cholecystitis followed by fibrosis and portal hypertension, one case of peptic ulceration and two cases of radiation hepatitis. All cases responded to appropriate therapy. CONCLUSION: Proper selection of patients and accurate interpretation of pre-treatment investigations are vital for minimizing adverse effects following therapy with SIR spheres. In our experience, all adverse effects were moderate with no life-threatening consequences.

Adult↗
PubMed2006

Intraepidermal animal-type melanoma.

Animal-type melanoma is a rare variant of melanoma in humans.1 Its name is derived from its histological appearance, which is similar to that described in melanomas occurring in white or gray horses.2 All tumors are dermally located, and characterized by a proliferation of deeply pigmented elongated or rounded cells, showing moderate atypia and a low mitotic rate. In some tumors, secondary infiltration of the epidermis has been noted. More than half of the patients are younger than 30 years, and prognosis seems to be much better than that expected for a superficial spreading or nodular melanoma of the same size. We report the first case of animal-type melanoma in situ.

Adult↗
PubMed2003

Changes in endometrial blood vessels in the endometrium of women with hormone replacement therapy-related irregular bleeding.

BACKGROUND: Irregular bleeding affects up to 60% of hormone replacement therapy (HRT) users. The mechanism of this bleeding is not understood. Reduced endometrial microvascular integrity appears to underlie breakthrough bleeding in pre-menopausal women and the aim of this study was to establish whether similar changes are seen in HRT users and hence to elucidate a possible mechanism of irregular bleeding. METHODS: Endometrium from 34 HRT users with amenorrhoea, irregular bleeding or regular bleeding was assessed for endometrial endothelial cell density (anti-CD34), number of blood vessels per mm(2), vascular basal lamina components (laminin, collagen IV and heparan sulphate proteoglycan) and in 32 subjects and 23 controls for perivascular smooth muscle alpha (SMA). Findings were compared with a control population of 29 post-menopausal women not using HRT, other sex steroids or tamoxifen and with no vaginal bleeding. Staining intensity was assessed in a blinded fashion in all immunohistochemical studies. RESULTS: Four significant differences in endometrial blood vessels were observed between HRT users and controls: (i) a significantly lower density of endometrial endothelial cells (EC staining for CD34) per mm(2) was present in HRT users compared with controls (P < 0.001); (ii) endothelial cells (EC) were predominantly organized within blood vessels (83%) in controls but in HRT users EC were dispersed in the tissues with only 29% in organized vessels (P <0.001); (iii) supportive perivascular cell SMA was significantly reduced in 23 post-menopausal HRT users compared with 23 post-menopausal controls (n = 29, P = 0.013) and (iv) an atrophic or inactive histological pattern of endometrium was more frequently seen in the controls (P < 0.001). CONCLUSIONS: These findings support the hypothesis that exposure to HRT profoundly alters endometrial blood vessels, reducing structural integrity thereby predisposing to irregular bleeding in HRT users.

Actins↗
PubMed2001

Epithelial cancer cell migration: a role for chemokine receptors?

We investigated the possibility that chemokine gradients influence migration of human ovarian epithelial tumor cells. Of 14 chemokine receptors investigated, only CXCR4 was expressed on ovarian cancer cells. CXCR4 mRNA localized to a subpopulation of tumor cells in ovarian cancer biopsies. Ovarian cancer cell lines and cells freshly isolated from ascites expressed CXCR4 protein. The CXCR4 ligand, CXCL12, was found in ascites from 63 patients. CXCL12 elicited intracellular calcium flux and directed migration and changes in integrin expression in ovarian cancer cells. CXCR4 may influence cell migration in the peritoneum, a major route for ovarian cancer spread, and could be a therapeutic target.

Ascitic Fluid↗
PubMed2001

Perineal massage in labour and prevention of perineal trauma: randomised controlled trial.

OBJECTIVE: To determine the effects of perineal massage in the second stage of labour on perineal outcomes. DESIGN: Randomised controlled trial. PARTICIPANTS: At 36 weeks' gestation, women expecting normal birth of a singleton were asked to join the study. Women became eligible to be randomised in labour if they progressed to full dilatation of the cervix or 8 cm or more if nulliparous or 5 cm or more if multiparous. 1340 were randomised into the trial. INTERVENTION: Massage and stretching of the perineum during the second stage of labour with a water soluble lubricant. MAIN OUTCOME MEASURES PRIMARY OUTCOMES: rates of intact perineum, episiotomies, and first, second, third, and fourth degree tears. SECONDARY OUTCOMES: pain at three and 10 days postpartum and pain, dyspareunia, resumption of sexual intercourse, and urinary and faecal incontinence and urgency three months postpartum. RESULTS: Rates of intact perineums, first and second degree tears, and episiotomies were similar in the massage and the control groups. There were fewer third degree tears in the massage group (12 (1.7%) v 23 (3.6%); absolute risk 2.11, relative risk 0.45; 95% confidence interval 0.23 to 0.93, P<0.04), though the trial was underpowered to measure this rarer outcome. Groups did not differ in any of the secondary outcomes at the three assessment points. CONCLUSIONS: The practice of perineal massage in labour does not increase the likelihood of an intact perineum or reduce the risk of pain, dyspareunia, or urinary and faecal problems.

Adult↗
PubMed2001

Cyclooxygenase-2: a possible target in schistosoma-associated bladder cancer.

OBJECTIVE: To analyse and compare the expression of cyclooxygenase (COX) enzymes in schistosoma-associated bladder cancer, and to determine any association with tumour grade or stage. MATERIALS AND METHODS: Sixty paired samples of tumour and adjacent nonmalignant urothelium were identified. There were 25 squamous and 28 transitional cell carcinomas, and seven adenocarcinomas. Serial sections were obtained and a standard three-layer immunohistochemistry protocol, using COX-1- and COX-2-specific mouse monoclonal antibodies, applied. RESULTS: COX-1 was expressed mostly in nonvascular smooth muscle with weak reactivity in malignant and nonmalignant urothelium. Nonmalignant urothelium expressed COX-2 weakly, notably in areas of dysplasia and squamous metaplasia whereas there was a significant increase in COX-2 (P < 0.001) with moderate to strong granular cytoplasmic expression in all three malignant histological types. The COX-2 reactivity was higher in transitional and adenocarcinomas than in squamous cell carcinoma (P < 0.001). Areas of carcinoma in situ showed COX-2 reactivity comparable with that in invasive areas and more intense than that detected in dysplastic or metaplastic urothelium (P < 0.001). There was a statistically significant positive correlation between COX-2 expression and tumour grade (P = 0.0052). CONCLUSION: COX-2 is over-expressed in schistosoma-associated bladder cancer, consistent with a potential role for COX-2 inhibitors in the prevention and management of this disease.

Adenocarcinoma↗
PubMed2001

Postpartum positioning and attachment education for increasing breastfeeding: a randomized trial.

BACKGROUND: Although lactation experts suggest that a correct positioning and attachment technique reduces breastfeeding problems and enhances long-term breastfeeding, evidence from randomized trials is lacking. The objective of this study was to evaluate the effect of postpartum positioning and attachment education on breastfeeding outcomes in first-time mothers. METHOD: A randomized trial was performed in a public hospital in Adelaide, South Australia, where 160 first-time mothers were randomly allocated to receive either structured one-to-one education (experimental group) or usual postpartum care (control group) within 24 hours of birth. The primary outcome was breastfeeding at 6 weeks and 3 and 6 months postpartum; other outcomes were nipple pain and trauma in hospital and at 6 weeks and 3 and 6 months, and satisfaction with breastfeeding. RESULTS: No significant differences occurred in breastfeeding rates between the groups at each endpoint, although a trend in the direction of lower rates was seen at each endpoint in the experimental group. This group reported less nipple pain on days 2 (p = 0.004) and 3 (p = 0.04), but this was not sustained on follow-up. No differences were observed in nipple trauma in hospital or in self-reported nipple pain and/or trauma at the three endpoints. Experimental group women were less satisfied with breastfeeding at 3 and 6 months postpartum when using a one-item measure; however, a multiple-item measure showed no significant differences at the three endpoints. CONCLUSIONS: The intervention did not increase breastfeeding duration at any assessment time or demonstrate any differences between the groups on secondary outcomes. The trend toward lower breastfeeding rates in the experimental group suggests a need for a larger trial to evaluate whether or nor postpartum positioning and attachment education may negatively affect breastfeeding.

Adult↗
PubMed2001

Vascular endothelial growth factor transgenic mice exhibit reduced male fertility and placental rejection.

Recent evidence points to the involvement of vascular endothelial growth factor (VEGF) in mammalian reproductive physiology. Transgenic mice expressing VEGF (121 isoform) under the control of the polyepithelial mucin-1 (muc-1) promoter showed a reduction in male fertility due to impaired spermiogenesis, and aberrant placentation leading to preferential rejection of male embryos. A skew in the sex ratio of the litters was seen (three females to two males), independently of whether the transgene was carried by the male or female parent. In-situ hybridization permitted distinction of expression of the human VEGF transgene from endogenous mouse VEGF, and confirmed expression of the transgene in a wide range of epithelial tissues. Expression of the transgene in spermatocytes and in the embryonic portion of placenta is thought to be responsible for the reduced fertility and embryonic resorptions respectively. Males showed either complete sperm maturation arrest or various gradations of partial fertility. Abnormally high or low VEGF in human semen has been reported to be correlated with a lack of pregnancy success following IVF. The muc1-VEGF (121 isoform) transgenic mouse provides an animal model with which to further study this VEGF-induced pathology.

Animals↗
PubMed2000

Disruption of the developmentally regulated Rev3l gene causes embryonic lethality.

The REV3 gene encodes the catalytic subunit of DNA polymerase (pol) zeta, which can replicate past certain types of DNA lesions [1]. Saccharomyces cerevisiae rev3 mutants are viable and have lower rates of spontaneous and DNA-damage-induced mutagenesis [2]. Reduction in the level of Rev31, the presumed catalytic subunit of mammalian pol zeta, decreased damage-induced mutagenesis in human cell lines [3]. To study the function of mammalian Rev31, we inactivated the gene in mice. Two exons containing conserved DNA polymerase motifs were replaced by a cassette encoding G418 resistance and beta-galactosidase, under the control of the Rev3l promoter. Surprisingly, disruption of Rev3l caused mid-gestation embryonic lethality, with the frequency of Rev3l(-/-) embryos declining markedly between 9.5 and 12.5 days post coitum (dpc). Rev3l(-/-) embryos were smaller than their heterozygous littermates and showed retarded development. Tissues in many areas were disorganised, with significantly reduced cell density. Rev3l expression, traced by beta-galactosidase staining, was first detected during early somitogenesis and gradually expanded to other tissues of mesodermal origin, including extraembryonic membranes. Embryonic death coincided with the period of more widely distributed Rev3l expression. The data demonstrate an essential function for murine Rev31 and suggest that bypass of specific types of DNAlesions by pol zeta is essential for cell viability during embryonic development in mammals.

Animals↗
PubMed2000

Phenotypic and genotypic characterization of commonly used human prostatic cell lines.

OBJECTIVE: To investigate and catalogue systematically the phenotypic and genotypic characteristics of the commonly used prostatic cell lines using immunocytochemistry and polymerase chain reaction (PCR) of hypervariable sequences within the genome to provide a 'fingerprint' characteristic of each cell line. Materials and methods Malignant (LNCaP, LNCaP-r, PC-3, DU-145) and benign immortalized prostatic cell lines (PNT-1A, PNT-1B, BPH-1) were grown on four-well slides, fixed and subjected to indirect streptavidin-biotin immunocytochemistry. Twenty-three antibodies were used in the following groups: cytoskeletal elements: cytokeratins (CK)-5, -7, -8, -14 (two), -16, -18, -19 (three), -20, vimentin and desmin; MUC1 (three); cell adhesion molecules (E-cadherin, alpha-beta-and gamma-catenin); and prostatic associated proteins: prostate specific antigen (PSA), prostatic acid phosphatase (PAP) and androgen receptor (AR). For the PCR, genomic DNA was extracted from the cell lines and from SKOV3 and MCF7 (positive controls). PCR was performed on three variable regions which were then sequenced: AR exon 1 (CAG repeat polymorphism), and two areas of microsatellite instability (MSI): AR exon 8 and hypoxanthine-guanine phosphoribosyl transferase (HPRT) exon 3. RESULTS: All cell lines were CK-8/18 positive and most also expressed CK-7 and -19. Heterogeneous CK-20 expression was detected for the first time in prostatic cell lines. All lines were positive for vimentin and negative for desmin. MUC1 was expressed in one malignant (DU-145) and all immortalized cell lines. E-cadherin expression was low or absent in three lines: PNT1A, 1B and PC-3. Only PC-3 failed to express alpha-catenin; beta- and gamma-catenin were expressed by all lines. PSA, PAP and AR were only expressed by LNCaP and LNCaP-r. On PCR, the CAG repeat lengths in exon 1 of the AR ranged from 19 to 27. Three pairs of cell lines had the same exon 1 CAG repeat length: LNCaP/PC-3 (26 repeats), BPH-1/DU-145 (19 repeats) and PNT1 A/1B (20 repeats). Exon 8 sequences were identical except for LNCaP, which showed a single base mutation, and HPRT exon 3 sequences were all identical. There was no evidence of generalized MSI in any of the cell lines examined. CONCLUSIONS: The cell lines studied fell into three broad groups according to their phenotypic characteristics: (i) prostatic marker positive (LNCaP and LNCaP-r); (ii) high expression of most antigens (DU-145, PC-3 and BPH-1); and (iii) low or absent expression of most antigens (PNT1 A and 1B). Each of the cell lines derived from PC could be identified on the basis of exon 1 and 8 AR sequence variability. DU145 and BPH-1 had identical profiles of the three areas studied, but these cell lines are easily distinguished by their different phenotypic characteristics. PNT1A and 1B had identical genetic and similar phenotypic profiles, which is unsurprising given that they are subclones derived from the same parental line. Even so, these were separable on the basis of CK-19 immunostaining. Using a combination of geno- and phenotypic markers it was possible to derive a 'fingerprint' for each of the cell lines assessed, which will allow meaningful comparison between similar cell lines held in other laboratories.

Cadherins↗
PubMed1999

Mice deficient in tumor necrosis factor-alpha are resistant to skin carcinogenesis.

Given the associations between chronic inflammation and epithelial cancer, we studied susceptibility to skin carcinogenesis in mice deficient for the pro-inflammatory cytokine TNF-alpha (refs. 5,6). TNF-alpha(-/-) mice were resistant to development of benign and malignant skin tumors, whether induced by initiation with DMBA and promotion with TPA or by repeated dosing with DMBA. TNF-alpha(-/-) mice developed 5-10% the number of tumors developed by wild-type mice during initiation/promotion and 25% of those in wild-type mice after repeated carcinogen treatment. TNF-alpha could influence tumor and stromal cells during tumor development. The early stages of TPA promotion are characterized by keratinocyte hyperproliferation and inflammation. These were diminished in TNF-alpha(-/-) mice. TNF-alpha was extensively induced in the epidermis, but not the dermis, in TPA-treated wild-type skin, indicating that dermal inflammation is controlled by keratinocyte TNF-alpha production. Deletion of a TNF-alpha inducible chemokine also conferred some resistance to skin tumor development. TNF-alpha has little influence on later stages of carcinogenesis, as tumors in wild-type and TNF-alpha(-/-) mice had similar rates of malignant progression. These data provide evidence that a pro-inflammatory cytokine is required for de novo carcinogenesis and that TNF-alpha is important to the early stages of tumor promotion. Strategies that neutralize TNF-alpha production may be useful in cancer treatment and prevention.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1998

Comparison of three solid phase supports for promoting three-dimensional growth and function of human liver cell lines.

An extracorporeal liver support system will require that liver cells maintain their normal differentiated function. This is more likely to be achieved utilizing a three-dimensional culture configuration rather than a simple monolayer culture. We present data on a human liver cell line attached and maintained on different three-dimensional supports, porous glass (Siran), silicon (Immobasil), and calcium-alginate beads. Albumin, fibrinogen, prothrombin, alpha1-acid glycoprotein and alpha1-antitrypsin secretions were measured. Proliferation was slower on each of the three-dimensional supports than on the monolayer culture. The protein secretion of all 5 proteins was highest in cells encapsulated in alginate; silicon beads supported greater protein secretion than glass. Cells on silicon or within alginate were rounded; those on glass grew in 2 configurations as flattened monolayers and as rounded colonies. Cells in alginate secreted as much protein as the whole liver (e.g., albumin, 14.88 g/10(12) cells/day compared to the whole liver, approximately 12 g/day). Three-dimensional culture of a human liver cell line leads to both proliferation and a high synthetic capacity, an important feature of cells suitable for an extracorporeal liver support system.

Albumins↗
PubMed1997

Fibroblast growth factor receptor signalling has a role in lobuloalveolar development of the mammary gland.

We have used the mouse mammary tumor virus promoter to express two dominant negative (DN) fibroblast growth factor receptor (FGFR) isoforms in the mammary epithelium of transgenic mice. While expression of DN-FGFR1(IIIc) showed no discernible phenotype, a similar kinase negative form of FGFR2(IIIb) caused a marked impairment of lobuloalveolar development. The growth retardation was apparent by mid-pregnancy and persisted in the post-partum glands. Despite the substantial underdevelopment of the mammary gland there was a measurable lactational response, but it was insufficient to properly sustain the new-born pups. These findings demonstrate that fibroblast growth factor signalling is necessary for pregnancy dependent lobuloalveolar development of the mammary gland.

Animals↗
PubMed1995

Mice lacking cyclin D1 are small and show defects in eye and mammary gland development.

Using homologous recombination, mice lacking cyclin D1 were generated by replacing most of the first exon of the Cyl-1 gene with sequences encoding neomycin resistance. Cyl-1(-1-) mice were viable and fertile but consistently smaller than their heterozygous or wild-type littermates. The nullizygous animals also showed two distinctive abnormalities: a severe retinopathy caused by impaired development of all layers of the retina and, in the mammary gland during pregnancy, a marked reduction in acinar development accompanied by a failure to lactate. Approximately 50% of animals also had a malformation of the jaw that manifested itself as a misalignment of the incisor teeth. Mouse embryo fibroblasts isolated from 14 day nullizygous, heterozygous, or wild-type embryos and grown under standard conditions showed similar cell-cycle and growth characteristics. Thus although cyclin D1 kinase activity may facilitate G1 progression, it is not essential for the development of most tissues and organs, and only a few specialized cell lineages are demonstrably sensitive to its absence.

Animals↗
PubMed1995

Expression of integrin subunits in the human infant breast correlates with morphogenesis and differentiation.

Integrins are widely expressed on normal tissues and their function is considered critical directly or indirectly with the control of cell growth and differentiation. Also, they are likely to play a crucial role in cell-matrix interactions during development. As the human breast develops after birth, it provides a rare opportunity in which to study human organogenesis. We have examined the distribution of integrins in the human infant breast with the aim of elucidating the possible role of these molecules in morphogenesis and differentiation. Necropsy breast specimens from six male and eight female infants, ranging in age from 1 day to 9 months, were used in this study. Cryostat sections were stained by the avidin-biotin complex technique, using a panel of monoclonal antibodies (MAbs) which recognize beta 1, alpha 2, alpha 6, beta 4, alpha v, and alpha v beta 3 integrin chains, which are candidate molecules for a role in mammory morphogenesis. MAbs to beta 1 (DH12) and alpha 2 (HAS3) showed positive membrane and cytoplasmic staining of basal cells and luminal epithelial cells. In addition, positive staining for the beta 1 integrin chain was found on fibroblasts. A MAb which recognizes the alpha 6 chain (MP4F10) showed positive staining of the basal cells and heterogeneous staining of the luminal epithelial cells, whilst beta 4 chain (439-9B) showed positive staining in the basement membrane domain of the basal cells with no staining of the luminal epithelial cells. There was a positive correlation between the intensity of expression and the structural development of the ductal system, with integrin expression reduced or absent in the end buds and lateral buds.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗