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S J Hall

Publications and source records attributed to S J Hall.

At least 37 records · Page 2Linked to original sources
PubMed2000

Direct exposure of mouse spermatogenic cells to high doses of adenovirus gene therapy vector does not result in germ cell transduction.

The potential for adenovirus gene therapy vectors to gain access to male germ cells was rigorously tested in the mouse by injecting high titers of the vector directly into the testis and epididymis, or by exposing sperm to the vector immediately prior to or during in vitro fertilization. The adenovirus vector carried the bacterial lacZ gene (Adbeta-Gal) driven by the Rous sarcoma virus (RSV) promoter, and infection was assessed by testing for lacZ expression, either with antibodies to LacZ protein or by staining for LacZ enzymatic activity. A total of 109 plaque-forming units (PFU) was inserted into the testis or epididymis, and in vitro fertilization was performed after sperm were exposed either to 10 or 100 PFU per sperm cell. lacZ expression was examined within testes for several weeks after injection, and in preimplantation embryos produced by in vitro fertilization with sperm exposed to the gene therapy vector. Direct injection of Adbeta-Gal into either the testis or epididymis resulted in lacZ expression only within the interstitium of the testis and not within seminiferous tubules. Despite direct exposure of spermatogenic cells or mature sperm to high titers of virus, lacZ expression was likewise not detected in embryos. These findings are consistent with the conclusion that the risk is minimal for germ line integration of adenovirus vectors exposed to male reproductive cells.

Adenoviridae↗
PubMed2000

Prospects for herpes-simplex-virus thymidine-kinase and cytokine gene transduction as immunomodulatory gene therapy for prostate cancer.

In completed and ongoing clinical trials, adenovirus-mediated (Ad.) expression of herpes-simplex-virus thymidine-kinase (HSV-tk) gene transduction followed by ganciclovir (GCV) therapy has produced limited toxicity and evidence of antitumor activity following injection of the prostate. Furthermore, this system has been shown to direct systemic antitumor activity in several experimental cancer models, including that of prostate cancer, which may serve as the basis for in-situ immunomodulatory gene therapy. In a mouse model of prostate cancer, natural killer (NK) cells have been identified as the mediator of antimetastatic activity following Ad.HSV-tk + GCV, resulting in the combination of Ad.HSV-tk and adenovirus-mediated expression of interleukin 12 (Ad.IL-12) to exploit this cytokine's ability to enhance NK proliferation and cytotoxicity. Combination therapy demonstrated superior local and systemic growth suppression over that obtained with either therapy alone. Importantly, when the metastatic tumor burden was increased to an extent that negated the growth-suppressive activity directed by Ad.HSV-tk + GCV or Ad.IL-12 alone, combination therapy continued to demonstrate significant growth suppression. Examination of tumor-infiltrating lymphocytes documented enhanced NK lytic activity following combination therapy. Therefore, it appears that the combination of Ad.HSV-tk and Ad.IL-12 should be validated in a clinical trial for the treatment of prostate cancer.

Adenoviridae↗
PubMed2000

Adenovirus mediated cytosine deaminase gene transduction and 5-fluorocytosine therapy sensitizes mouse prostate cancer cells to irradiation.

PURPOSE: We assess the ability of adenovirus mediated expression of the Escherichia coli cytosine deaminase gene in conjunction with the prodrug 5-fluorocytosine to result in radiation sensitization in the mouse prostate cancer cell line RM-1 in vitro. MATERIALS AND METHODS: To document cytotoxicity of gene therapy, RM-1 cells were exposed to escalating doses of adenovirus mediated cytosine deaminase and a fixed dose of 5-fluorocytosine or phosphate buffered saline. Viable cells as determined by exclusion of trypan blue were counted the following day. Cytosine deaminase expressing RM-1 cells were then irradiated as single cell suspensions at various doses of radiation in a cesium source (4.4 Gy. per minute) and randomized to receive 5-fluorocytosine therapy at different times in relation to the external radiation therapy. End points were determined in a clonogenic assay by counting colonies with greater than 50 cells 7 days after replating. RESULTS: Use of adenovirus mediated cytosine deaminase plus 5-fluorocytosine demonstrated viral dose dependent killing of RM-1 cells to a maximum of 85%, while either therapy alone was nontoxic. Neither adenovirus mediated cytosine deaminase infection nor 5-fluorocytosine alone influenced external radiation therapy killing. However, after controlling for death due to gene therapy alone, the combination of adenovirus mediated cytosine deaminase plus 5-fluorocytosine and external radiation therapy resulted in synergistic activity to approximately 2 logs of cell kill at low doses of radiation (p = 0.001). While altering the chronology of prodrug exposure in relation to external radiation therapy maintained synergy in all scenarios tested, starting 5-fluorocytosine 24 hours before external radiation therapy resulted in the most profound killing (p = 0.04), which indicates the importance of maintaining prodrug therapy during external radiation therapy. CONCLUSIONS: The combination of adenovirus mediated cytosine deaminase plus 5-fluorocytosine and radiation therapy resulted in radiation sensitization with clinically relevant doses of radiation suggesting a potential usefulness of this treatment in patients with prostate cancer.

Adenoviridae↗
PubMed1999

Prodrug activation gene therapy and external beam irradiation in the treatment of prostate cancer.

OBJECTIVES: Gene therapy may represent a new avenue for the development of multimodal treatment for men with locally advanced prostate cancer. This study explores the potential benefits of combining adenovirus-mediated (ADV) herpes simplex virus thymidine kinase gene (HSV-tk) transduction and ganciclovir (GCV) therapy with external beam radiation therapy (XRT) to enhance the therapeutic efficacy of each treatment alone. METHODS: ADV/HSV-tk-transduced mouse prostate cancer cells, RM-1, were irradiated as single-cell suspensions at escalating doses in a cesium source (4.4 Gy/min). HSV-tk-expressing cells were randomized to receive varying doses and varying chronologies of GCV therapy in relation to XRT to fully evaluate potential cooperative activities. End points were determined in a clonogenic assay by counting colonies with greater than 50 cells 7 days after replating. The potential role of apoptosis as a mediator of enhanced cell killing was addressed by a TUNEL assay 12 and 24 hours after therapy. RESULTS: Neither ADV infection nor GCV alone affected XRT killing. However, the combination of ADV/HSV-tk+GCV plus XRT maintained the 1 log of cell kill from gene therapy alone through escalating doses of radiation. Radiation sensitization was noted at higher doses of radiation (8.8 Gy or more). Although decreasing the GCV dose had a profound negative influence on HSV-tk+GCV-mediated killing, combination therapy continued to maintain the degree of HSV-tk+GCV killing through escalating doses of XRT in an additive fashion but did not result in radiosensitization. Changing the chronology of GCV exposure in relation to XRT did not significantly alter the additive activities of combination therapy. Studies of apoptosis noted a doubling of apoptotic activity with HSV-tk+GCV compared with HSV-tk+PBS with or without XRT. However, there was no significant change in apoptotic activity in combination therapy over HSV-tk+GCV alone within the 24-hour period after GCV exposure. CONCLUSIONS: The combination of ADV/HSV-tk+GCV and XRT appears to result in at least additive, and with higher doses of radiation, synergistic killing activities, indicating a potential usefulness of this treatment strategy for patients with prostate cancer.

Animals↗
PubMed1998

Induction of potent antitumor natural killer cell activity by herpes simplex virus-thymidine kinase and ganciclovir therapy in an orthotopic mouse model of prostate cancer.

Adenovirus-mediated transduction of the herpes simplex virus-thymidine kinase (HSV-tk) gene followed by ganciclovir is suspected to induce immune-mediated, systemic antitumor activities in the RM-1 mouse prostate cancer model (S. J. Hall et al., Int. J. Cancer, 70: 183-187, 1997). Although numerous investigators have also implied a role for the immune system in both local and systemic effects resulting from HSV-tk treatment, the candidate effector cell(s) mediating these activities are unknown. Fresh lymphocytes harvested from treated tumors (tumor-infiltrating lymphocytes) generated significant in vitro lytic activity against the parental cell line, RM-1, and an unrelated prostate cancer cell line. In vitro antibody and complement depletion of CD3+ T cells and natural killer (NK) cells from tumor-infiltrating lymphocytes indicated that NK cells were the dominant mediator of the observed tumor cell lysis. Concurrently, no cytotoxic T-cell activity was ascertained within splenocytes of treated mice. In vivo depletion of NK cells resulted in a 20% reduction in growth suppression within the primary tumor and complete abrogation of the inhibition of preestablished lung metastases. Depletion of T cells had no effect on either response. Here, we identify the presence of NK cells within adenovirus/HSV-tk- and ganciclovir-treated tumors, which serve to mediate both local and systemic antitumor activities in this model, and lay the mechanistic groundwork for further improvements in this gene therapy strategy.

Adenoviridae↗
PubMed1998

Traditional livestock in semi-arid north eastern Zimbabwe: Mashona cattle.

Productivity data were gathered from Mashona cows (n = 187) in 28 traditionally managed herds in two areas, separated by a corridor 20-30 km wide of almost uninhabited bush in NE Zimbabwe. Cattle are kept primarily to provide oxen for work. Cows in the southern area, which had been more affected by drought in 1991-92, were younger (7.2 vs. 9.1 years) and had a longer median calving interval (548 vs. 406 days). Metrical data (n = 105 cows) showed these cattle to be larger-bodied than those in the northern area (heart girth 146 vs. 144 cm). Market prices, estimated by respondents, were higher for oxen and herds were smaller in the south, and calf survival was believed by owners to be more influenced by season of birth in this area. Data were obtained on 531 calves. Before the age of 12 months 6.2% died, a low proportion compared with other studies. Most were retained in herds but 11.5% were slaughtered, sold or given away. All owners practised castration, selecting fast growing, strong bull calves for breeding.

Animal Husbandry↗
PubMed1998

Welfare aspects of the transport by road of sheep and pigs.

That transport can be stressful to pigs and sheep has been inferred from behavioral and physiological measurements. Duration of journey is more likely to cause stress in pigs than in sheep, but loading and the start of travel are stressful to both. Vibration, related to vehicle design, and the jolting, shocks, and sudden impacts caused by road conditions and manner of driving, are probably of more importance than noise. Ventilation and stocking density can modulate the effects of ambient temperature, which may influence meat quality in pigs. Deprivation of food and water does not appear to stress sheep unduly, but this can become a serious welfare concern in the case of pigs. However, most journeys undertaken by pigs in the European Union are relatively short. In sheep, transport may follow soon after other stressful experiences such as weaning, shearing, handling, or marketing; the interaction of these factors in causing cumulative stress has not been studied. In pigs, fighting after the mixing of previously unacquainted animals is well known to be a welfare issue that can compromise meat quality. Considering the public interest in livestock transport and the large amounts of money involved, surprisingly little research has been done in the area, and more is urgently needed for legislation and welfare codes to be soundly based on scientific knowledge.

Journal Article↗
PubMed1997

Cloning and characterization of the 5' flanking region of the stem cell factor gene in rat Sertoli cells.

In order to elucidate the molecular basis of stem cell factor (SCF, or steel factor/kit ligand) expression in Sertoli cells of rat testis, 1.5 kb of the 5' flanking region of the SCF gene was isolated and characterized. The transcriptional start point (tsp) was identified by primer extension assay and a rapid amplification of cDNA ends (RACE) assay. A TATA box was found 29 base pairs (bp) upstream from the tsp, and a number of transcription factor consensus sequences, including several AP2 and Spl sites, were identified. The transcriptional activity of the 1.5 kb 5' flanking region was analyzed by deletion constructs using a firefly luciferase-encoding gene (luc) expression vector transiently transfected into primary rat Sertoli cells and other SCF positive and negative cell lines. For all the cells and cell lines examined, a -119 bp to +43 bp fragment including the tsp was sufficient for SCF promoter activity, and the core promoter activity was not significantly changed by inclusion of upstream sequences as far as -1461 bp. These results indicate that additional sites outside of this promoter region are needed to define the cell-specific regulatory elements of SCF expression. The transcriptional activities of all SCF deletion constructs treated with cyclic adenosine 3',5'-monophosphate (cAMP) and forskolin were increased two- to threefold, indicating that SCF transcription in Sertoli cells is regulated by a cAMP-dependent pathway in the proximal promoter region.

3T3 Cells↗
PubMed1997

Adenovirus-mediated herpes simplex virus thymidine kinase gene and ganciclovir therapy leads to systemic activity against spontaneous and induced metastasis in an orthotopic mouse model of prostate cancer.

It is critical to develop new therapies, such as gene therapy, which can impact on both local and metastatic prostate cancer progression. We have developed an orthotopic mouse model of metastatic prostate cancer using a cell line (RM-1) derived from the mouse prostate reconstitution (MPR) model system. This mouse model closely simulates the anatomical and biological milieu of the prostate and allows for realistic testing of experimental gene therapy protocols. Adenovirus (ADV)-mediated transduction of the herpes simplex virus thymidine kinase (HSV-tk) gene in conjunction with ganciclovir (GCV) in this model led to significant suppression of growth and of spontaneous metastasis at 14 days post-tumor inoculation. Longer-term studies produced a significant survival advantage and a continued suppression of metastatic activity for treatment animals despite regrowth of the primary tumor. Challenge by injection of tumor cells into the tail vein following excision of treated and control s.c. primary tumors resulted in 40% reduction in lung colonization in the treatment group, indicating the possible production of systemic anti-metastatic activity following a single in situ treatment with ADV/HSV-tk + GCV in this model system.

Adenoviridae↗
PubMed1997

Identification of a P-glycoprotein-deficient subpopulation in the CF-1 mouse strain using a restriction fragment length polymorphism.

There is a subpopulation of the CF-1 mouse strain that is very sensitive to the neurotoxicity induced by the avermectins, a class of natural products widely used in veterinary and human medicine as anti-parasitic agents. This sensitivity results from a lack of P-glycoprotein in the intestine and brain of sensitive animals, allowing increased penetration of these compounds in the blood and brain, respectively. We describe a restriction fragment length polymorphism that is able to predict which animals will be deficient in this protein, confirming at the genetic level a heterogeneous population of this mouse strain. Breeding studies demonstrated that the inheritance of the markers follows a normal Mendelian autosomal pattern. Sensitive "-/-" animals are deficient in P-glycoprotein in those tissues known to express primarily mdr1a, but have normal P-glycoprotein levels in tissues known to express primarily mdr1b or mdr2, suggesting that the defect in the sensitive animals is limited to the mdr1a gene. The P-glycoprotein expression in the brain is dependent on the genotype, which also determines the susceptibility to the avermectin-induced neurotoxicity, with the "-/-" animals being most sensitive, and the "+/-" animals having less P-glycoprotein and therefore increased CNS sensitivity compared to the "+/+" animals. The ability to segregate this strain into -/- and +/+ animals may prove useful for examining the physiological role of P-glycoprotein in drug absorption and distribution and related toxicity. These data also provide a warning that experiments carried out with P-glycoprotein substrates in the heterogeneous population of the CF-1 mouse must be interpreted with caution.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Spontaneous but not experimental metastatic activities differentiate primary tumor-derived vs metastasis-derived mouse prostate cancer cell lines.

We previously developed an in vivo mouse prostate reconstitution (MPR) model of metastatic prostate cancer using p53 'knockout' mouse urogenital sinus tissue for retroviral transduction of ras and myc oncogenes (Thompson et al., Oncogene, 10, 869, 1995). We further demonstrated contrasting responses to transforming growth factor beta-1 (TGF-beta1) in three matched pairs of early passage cell lines derived from primary prostate tumors and lung metastases generated by this model system (Sehgal et al., Cancer Res, 56, 3359, 1996). In this study we tested these cell lines for growth potential in subcutaneous and orthotopic (dorso-lateral prostate) locations and metastatic activities in both spontaneous and experimental assays. Subcutaneous and orthotopic tumors produced by cell lines derived from metastatic lesions tended to grow less rapidly but demonstrated greater spontaneous metastatic potential than the cell lines derived from primary tumors. In contrast all cell lines produced lung colonies in an experimental metastasis assay (tail vein inoculation) with the primary tumor-derived cell lines yielding higher activities in two of three matched pair analyses. The ability of all cell lines to produce lung metastases in the experimental assay, while only the metastasis-derived cell lines retain the ability to initiate and complete the entire metastatic pathway in the spontaneous assay, suggests that intravasation may be the rate-limiting step in metastasis in this model system.

Animals↗
PubMed1997

A thalamic contribution to arousal-induced, non-photic entrainment of the circadian clock of the Syrian hamster.

It is well established that the circadian clock of the suprachiasmatic nuclei (SCN) is entrained by light. More recently, the potent effects of arousing, non-photic cues on the clock have been recognized. The neural mediators of non-photic entrainment are yet to be identified. To examine the contribution of the thalamic intergeniculate leaflet (IGL) and its NPY-immunopositive projection, the geniculo-hypothalamic tract to non-photic entrainment by arousal, male Syrian hamsters received lesions of the IGL (IGLX) which ablated NPY-immunoreactivity in the SCN. Their circadian responses to both photic and non-photic cues were then tested. Lesions resulted in a delay in the timing of activity onset following lights out, but had no effect on the behavioural or cellular circadian responses to phase-advancing light pulses presented at circadian time (CT) CT19 (where CT12 represents the time of activity onset). Injection with a benzodiazepine (chlordiazepoxide, 100 mg/kg) at CT6 suppressed wheel-running, increased general locomotion of intact controls and induced large phase advances of the circadian rhythm of wheel-running. Chlordiazepoxide also inhibited wheel-running in lesioned animals, but there was no significant increase in general locomotion and the lesioned animals did not phase advance. Serial arousal by injection of saline at intervals of 23.5 h for 6 days entrained the circadian rhythm of wheel-running of intact hamsters and was associated with an increase in general locomotor activity. Entrainment by serial arousal was abolished by IGLX. However, the lesioned animals did show a clear behavioural response to every presentation of the non-photic cue. These results show that the IGL is a necessary component of the neural pathways mediating both arousal- and benzodiazepine-induced non-photic entrainment.

Animals↗
PubMed1996

Canine epilepsy: a genetic counselling programme for keeshonds.

The predisposition of keeshonds (Dutch barge dogs) to an idiopathic epilepsy appears to be determined by a single autosomal recessive gene. The pedigrees of 15 litters which included animals diagnosed as epileptic ('fitters') were compared with those of 34 contemporary, normal animals. The pedigrees of all the fitters traced back, on both the paternal and maternal sides, to a common ancestor. Subsequently, further pedigrees and details of litters were gathered. If both parents of a fitter were heterozygous ('carriers'), the progeny (120 in number) of all known carrier x carrier matings would be expected to have a ratio of three phenotypically normal animals to one fitter, that is, 90:30. The ratio observed (91:29) was not significantly different. The Keeshond Club has published a list from which the identities of carriers can be inferred, with the intention that known carriers should be excluded from breeding. A genetic counselling programme has been in operation since 1989, which is based on advising breeders on the probability that the offspring of proposed matings would be fitters or carriers; advice has been given on 77 proposed matings. The mean probability that the proposed matings would result in carriers has declined significantly, and this is consistent with a decline in the frequency of the gene for this form of epilepsy in the breed.

Animals↗