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Biomedical subjects

A Livingstone

Publications and source records attributed to A Livingstone.

At least 19 recordsLinked to original sources
PubMed2005

Assessment in vitro of a novel therapeutic strategy for glioma, combining herpes simplex virus HSV1716-mediated oncolysis with gene transfer and targeted radiotherapy.

Genetically engineered herpes simplex virus ICP34.5 null mutants replicate only in dividing cells and have shown potential for the treatment of malignant disease, including glioma. Phase I trials have demonstrated the safety of these viruses in various clinical settings but it is envisaged that for full efficacy they will be used in combination with other therapeutic modalities. To enhance virus-induced tumour cytotoxicity, we have engineered an ICP34.5 null mutant (HSV1716) of HSV1 which expresses the noradrenaline transporter gene (NAT). This virus is designated HSV1716/NAT. We have shown previously that introduction of the NAT gene into a range of tumour cells, via plasmid-mediated transfection, conferred the capacity for active uptake of the radiopharmaceutical [131I]MIBG and resulted in dose-dependent toxicity. In this study, combination therapy utilising HSV1716/NAT and [131I]MIBG was assessed in vitro by the MTT assay. We demonstrate that the NAT gene, introduced by HSV1716/NAT into cultured glioma cells, was expressed 1 h after viral infection, enabling active uptake of [131I]MIBG. The combination of viral oncolysis and induced radiopharmaceutical uptake resulted in significantly enhanced cytotoxicity compared to either agent alone and the response was dose- and time-dependent. These studies show that the combination of oncolytic HSV therapy with targeted radiotherapy has the potential for effective tumour cell kill and warrants further investigation as a treatment for malignant glioma.

3-Iodobenzylguanidine↗
PubMed2004

Combining a targeted radiotherapy and gene therapy approach for adenocarcinoma of prostate.

A targeted radiotherapy/gene therapy approach for prostate cancer, using the radiopharmaceutical [(131)I]meta-iodobenzylguanidine ([(131)I]MIBG), would restrict the effects of radiotherapy to malignant cells, thereby increasing efficacy and decreasing morbidity of radiotherapy. Prostate cancer cells were transfected with a transgene encoding the noradrenaline transporter (NAT) under the control of tumour-specific telomerase promoters, enabling them to actively take up [(131)I]MIBG. This led to tumour-specific cell kill. This strategy has the advantage of generating a radiological bystander effect, leading to the destruction of neighbouring tumour cells that have escaped transfection. This targeted approach could be a promising tumour-specific treatment option for prostate cancer.

3-Iodobenzylguanidine↗
PubMed2004

Esophageal carcinoma: current controversial topics.

Worldwide, esophageal carcinoma is a common gastrointestinal cancer with a high mortality. The incidence of adenocarcinoma of the esophagus is increasing in the western world, but squamous cell carcinoma remains dominant in the underdeveloped parts of the world. Both types of esophageal carcinoma remain equally virulent. Currently, there are no optimal preventative screening programs available and most patients present with advanced or metastatic disease. Although many options are available for improving diagnostic accuracy, a single method has not displayed significant advantages over the others. In addition, selecting a superior treatment regimen has not surfaced. Preferred resection techniques exist, but one method has not illustrated improvements in survival over the others. A lack of improved survival rates with single modality therapies has led to a multi modality approach. However, developments in neoadjuvant and adjuvant therapies have led to mixed conclusions. Collectively, past studies have not shown an optimal neoadjuvant or adjuvant regimen in terms of survival benefit. This review highlights existing staging modalities and treatment regimens for esophageal carcinoma, in an effort to illustrate the controversial nature surrounding its management.

Antineoplastic Agents↗
PubMed2003

Virus replication in engineered human cells that do not respond to interferons.

The V protein of the paramyxovirus simian virus 5 blocks interferon (IFN) signaling by targeting STAT1 for proteasome-mediated degradation. Here we report on the isolation of human cell lines that express the V protein and can no longer respond to IFN. A variety of viruses, particularly slow-growing wild-type viruses and vaccine candidate viruses (which are attenuated due to mutations that affect virus replication, virus spread, or ability to circumvent the IFN response), form bigger plaques and grow to titers that are increased as much as 10- to 4,000-fold in these IFN-nonresponsive cells. We discuss the practical applications of using such cells in vaccine development and manufacture, virus diagnostics and isolation of newly emerging viruses, and studies on host cell tropism and pathogenesis.

Animals↗
PubMed2001

Expression in UVW glioma cells of the noradrenaline transporter gene, driven by the telomerase RNA promoter, induces active uptake of [131I]MIBG and clonogenic cell kill.

One of the most effective ways to kill cancer cells is by treatment of tumours with radiation. However, the administered dose of radiation to the tumour is limited by normal tissue toxicity. Strategies which decrease normal tissue exposure relative to tumour dose are urgently sought. One such promising scheme involves gene transfer, leading to the introduction of transporters specific for pharmaceuticals which can be labelled with radionuclides. We have previously demonstrated in vitro, that transfer of the noradrenaline transporter (NAT) gene, under viral promoter control, induces in host cells the active accumulation of the radiopharmaceutical [131I]meta-iodobenzylguanidine ([131I]MIBG) which results in kill of clonogens. We now report 17-fold enhancement of [131I]MIBG uptake by UVW glioma cells transfected with the NAT gene whose expression is driven by the human telomerase RNA (hTR) promoter (70% the uptake achieved by the strong viral promoter). Multicellular spheroids composed of hTR-NAT-transfected UVW cells exhibited dose-dependent susceptibility to treatment with [131I]MIBG. This was demonstrated by decreased survival of clonogens and complete sterilization of clonogens derived from spheroids and also failure of spheroids to regrow after administration of 7 MBq/ml [131I]MIBG. These data suggest hTR regulated expression of NAT may be an effective gene therapy strategy.

3-Iodobenzylguanidine↗
PubMed2001

Benign and solid tumors of the liver: relationship to sex, age, size of tumors, and outcome.

From 1983 through 1997, our center diagnosed 130 cases of benign neoplasms: 27 with focal nodular hyperplasia (FNH), 25 with hepatic adenoma, 71 with cavernous hemangioma, and seven with mixed tumors of different diagnoses. Most often these lesions were seen in females [female-to-male ratio (f/m): 5.5/1]. Hepatic adenomas and mixed tumors were seen exclusively in females and FNH predominantly in females (f/m: 26/1). Hemangiomas, however, were not uncommon in men (f/m: 52/19) relative to the other tumors (P < 0.001). Furthermore patients with hemangioma were older (mean age: 49 years) whereas patients with hepatic adenoma, FNH, and mixed tumors were often younger (mean age: 33, 35, and 44 years respectively; P < 0.004). Oral contraceptive steroid use was related by 21 of 25 patients (84%) with hepatic adenoma, 22 of 26 (85%) females with FNH, five of seven (71%) females with mixed tumors, and 10 of 52 (19%) patients with hemangioma. Ninety-five of the 130 patients (73%) had one or more symptoms. There was no statistically significant correlation between symptoms and the size of the lesion, the final diagnosis, and whether there were solitary or multiple masses. Three of 25 (12%) with hepatic adenoma presented with rupture, and one of 27 (4%) with FNH had such a consequence. None of the hemangiomas presented with rupture or progressed to such a state. One patient with hepatic adenoma (4%) had a focus of malignancy. Surgical removal of benign tumors was performed in 82 of 130 patients (63%), and there was one operative mortality (1.2%) in a patient who had a caudate lobe FNH. The types of surgical procedures included segmentectomy (62%), lobectomy (34%), and trisegmentectomy (4%). In two of 84 patients who had undergone laparotomy resection was not technically possible. Resection is recommended in all cases of hepatic adenoma because of fear of rupture or associated focus of malignancy. FNH was not observed to undergo a malignant transformation and will rarely rupture. Surgery is only recommended for symptomatic hemangioma, and size of the lesion is not a criterion for excision.

Adenoma, Liver Cell↗
PubMed2000

A gene therapy approach to enhance the targeted radiotherapy of neuroblastoma.

BACKGROUND: The aims of this study were to determine whether the introduction and expression of the noradrenaline transporter (NAT) gene into NAT-negative neuroblastoma cell lines would make them amenable to targeted radiotherapy using [(131)I]MIBG. PROCEDURE: Neuroblastoma cell lines were transfected with a eukaryotic expression vector containing the bovine noradrenaline transporter cDNA under the expression of the CMV promoter. Stable transfectants were created by selection in geneticin (G418) and were characterised for their MIBG uptake ability and susceptibility to [(131)I]MIBG therapy. RESULTS: The cell line SK-N-MC, which normally shows no ability to take up MIBG, was successfully transfected with bNAT. SK-N-MC.bNAT transfectants exhibited uptake and release kinetics similar to those of the natural NAT-expressing cell line SK-N-BE(2c). Levels of [(131)I]MIBG uptake were 33% of those of the highest naturally NAT-expressing cell line SK-N-BE(2c). Growth delay assays using multicellular spheroids indicated that this degree of [(131)I]MIBG uptake was sufficient to inhibit growth at radioactive concentrations of 4 Mbq/ml. CONCLUSIONS: These results demonstrate the feasibility of combining gene therapy with targeted radiotherapy to enhance uptake, and hence radiation dose, to neuroblastoma tumours using [(131)I]MIBG. With the appropriate delivery vehicle and tumour-specific control of expression, the introduction of noradrenaline transporter molecules may be a viable means of enhancing the response of neuroblastoma tumours to [(131)I]MIBG therapy.

Carrier Proteins↗
PubMed2000

Dose-response relationship for radiation-induced mutations at micro- and minisatellite loci in human somatic cells in culture.

PURPOSE: The study was designed to determine the dose-response relationship for radiation induction of mutations at mini- and microsatellite loci in human somatic cells. Mutations induced by graded doses of gamma-irradiation were quantified by screening clones derived from single irradiated cells for micro- and minisatellite alterations following irradiation with 1, 2 or 3 Gy. MATERIALS AND METHODS: After irradiation, the moderately radioresistant glioma cell line UVW was seeded at low density into Petri dishes to allow formation of discrete colonies, 100 of which were examined at each dose. All the cells within a colony were presumed to have arisen from a single irradiated cell. Radiation-induced microsatellite alterations were determined at 16 different loci, by PCR amplification and visualization on polyacrylamide gels. Minisatellite alterations were identified at four different minisatellite loci by restriction enzyme digestion and Southern blotting. RESULTS: A dose-response curve for mutation frequency was obtained by analysis of 100 clones, yielding a minisatellite mutation rate of 5.5x10(-3) mutations/locus/Gy/cell and a microsatellite mutation rate of 8.75x10(-4) mutations/locus/ Gy/cell. At microsatellite loci, alterations were predominantly simple loss or gain of repeat units and loss of heterozygosity (LOH). The mutations in minisatellite loci resulted predominantly in LOH and variation in repeat number. The background instability at each locus was determined by analysis of non-irradiated clones. Only 2% and 1% of the micro-and minisatellite loci respectively showed altered bands. CONCLUSIONS: This is the first report of a dose-response relationship for radiation-induced micro- and minisatellite mutations in human somatic cells. Described is a sensitive method for analysis of low-dose radiation mutagenesis in somatic cells that may prove to be a useful tool for radiation protection and dosimetry.

Dose-Response Relationship, Radiation↗
PubMed1999

Experience with staging laparoscopy in pancreatic malignancy.

BACKGROUND: The role of diagnostic laparoscopy in the staging of abdominal malignancies is not well defined. METHODS: We retrospectively reviewed the usefulness of diagnostic laparoscopy as a staging procedure in pancreatic malignancy. This experience between February 1988 and May 1997 involves 109 cases of suspected or proven pancreatic malignancy. All laparoscopies were performed with the patient under conscious sedation and local anesthesia in an endoscopy suite. RESULTS: Of the 109 patients with pancreatic cancer, 45 (42%) had metastatic disease. The use of computed tomography (CT) alone revealed the existence of liver metastases in 10 of 109 (9%) patients, which were confirmed laparoscopically. The further use of laparoscopy identified metastases in 29 more cases: hepatic, 23; hepatic and peritoneal, 3; peritoneal and mesenteric, 1; and mesenteric, 2. CT in conjunction with laparoscopy therefore revealed metastatic liver, peritoneal, or mesenteric lesions in 39 of 109 (36%) patients with pancreatic cancer. After staging laparoscopy, 67 of 69 patients underwent laparotomy. Metastatic disease was identified at laparotomy in 6 more patients; however, only 4 of these patients had metastases to the liver whereas 2 had metastases to the peripancreatic lymph nodes. Therefore, in patients with pancreatic malignancy, the negative predictive value for the diagnosis of metastases to the liver, peritoneum or mesentery was 94% (61 of 65 patients). The positive predictive value of laparoscopy alone for the detection of metastatic disease to the liver, peritoneum, or mesentery was 88% (29 of 33 patients). Laparoscopy was successfully performed without complications in all patients with pancreatic cancer; however, one had a technically unsatisfactory examination. The overall rate of resectability after staging by imaging studies and laparoscopy was 57% (35 of 61 patients). CONCLUSIONS: In patients with a negative CT for metastases, laparoscopic identification of metastases avoided unnecessary laparotomy in 29 of 99 (29%) patients with pancreatic cancer. Staging laparoscopy is indicated in all cases of pancreatic malignancy before an attempt at a surgical cure.

Aged↗
PubMed1999

Feasibility of spirometry and reversibility testing for the identification of patients with chronic obstructive pulmonary disease on asthma registers in general practice.

There is renewed interest in the diagnosis of chronic obstructive pulmonary disease (COPD) within primary care. Primary care physicians have difficulty distinguishing asthma from COPD. We tested the feasibility of using spirometry and if appropriate, reversibility testing, to identify patients with COPD on asthma registers in primary care. We carried out a cross-sectional study in three inner-city group practices in east London. Three hundred and twenty-eight patients aged 50 years and over on practice asthma registers were invited to attend for spirometry and, if appropriate, a trial of oral corticosteroids. The main outcome measures were: feasibility of carrying out spirometry; lung function; severity of COPD; prior diagnosis of COPD; response to a corticosteroid trial; quality of life. One hundred and sixty-eight of 328 (51%) patients attended for spirometry. According to British Thoracic Society criteria, 58 (34%) patients had normal spirometry at the time of assessment; 40 (24%) had active asthma and 57 (34%) had COPD. Thirteen patients (8%) were unable to perform spirometry. Of 57 patients with COPD 30 (53%) had mild, 15 (26%) had moderate and 12 (21%) had severe disease. Twenty-three of 57 (40%) patients with COPD on spirometry had this diagnosis recorded prior to the study. New diagnoses of COPD were more likely in those with mild or moderate disease (P<0.05). Twenty-three of 57 (40%) patients with COPD completed a corticosteroid trial: one showed significant reversibility of lung function. Spirometry was feasible and helped identify patients with COPD on asthma registers in these inner-city practices. Patients aged 50 years and over on asthma registers had a wide spectrum of lung function with considerable diagnostic misclassification. Some patients with normal lung function when tested may have had well controlled asthma. New diagnoses of COPD were mainly in those with mild or moderate disease.

Aged↗
PubMed1998

Laparoscopic cholecystectomy in cirrhotic patients.

BACKGROUND: Reported mortality for open cholecystectomy in patients with cirrhosis ranges from 10% to 80%. Laparoscopic cholecystectomy has gained acceptance in the general population and has become the procedure of choice for symptomatic cholelithiasis. We reviewed our experience with the use of laparoscopic cholecystectomy in this group. STUDY DESIGN: We did a retrospective review of the records of 25 consecutive laparoscopic choleoystectomy procedures performed on cirrhotic patients from May 1992 to July 1996. RESULTS: There were no mortalities in our group. All procedures were completed laparoscopically. Mean length of stay was 1.7 days (range, 1 to 8 days). Morbidity consisted of wound hematomas, pneumonia, and ascites for a rate of 32%. Only patients with Child's Class A and Class B cirrhosis were operated on. CONCLUSIONS: Laparoscopic cholecystectomy can be performed safely in cirrhotic patients with well compensated liver function.

Adult↗
PubMed1998

Translational control: a general mechanism for gene regulation during T cell activation.

Distributional changes of individual mRNAs between free ribonucleoprotein particles (mRNP) and ribosome-bound transcripts are used to assess translational control. Simultaneous analysis of many mRNA species is required to estimate the overall contribution of translation to the regulation of gene expression. To this purpose, total cytoplasmic RNA was fractionated in sucrose step gradients and poly(A)+ RNA was prepared from mRNP and ribosome-bound fractions. Since direct, simultaneous analysis of a profusion of mRNAs is not feasible, distribution of their in vitro translation products was examined after separation in 2-dimensional gels, followed by computer-based analysis of autoradiographs. When this analysis was applied to antigenically stimulated T cells, 36% of in vitro translation products showed a greater than 10-fold increase in intensity, suggesting transcriptional activation of the corresponding mRNAs. In comparison, 7.9% of individual mRNAs (54 of 685 species) were translationally activated. They were redistributed from free mRNP to ribosome-associated fractions; 4.7% (32 species) were translationally repressed, as indicated by the opposite pattern. The differential recruitment of 12.6% of mRNA species demonstrates specificity and the general significance of translational control during T cell activation, which implies that translation may play a similar role in regulating gene expression in a variety of physiological processes.

Animals↗
PubMed1998

The role of liver transplantation in the subacute trauma patients.

Two case reports are presented involving complex liver traumas requiring the need for liver transplantation. Both of these patients were designated unsalvageable until the transplant team was consulted. It is imperative that surgeons involved with complex hepatic trauma not give up hope and include these patients as potential liver recipients when irreversible liver failure occurs.

Adult↗
PubMed1997

N-myc amplification and its relationship to experimental therapy.

N-myc amplification correlates with poor prognosis in neuroblastoma patients. Although the reason for this is unclear, it is possible that amplified N-myc confers resistance to certain agents used in the therapy of the disease. The acquisition of resistance to cytotoxic drugs in human tumor cells is multifactorial. One mechanism involved in the development of drug resistance is an increased efficiency of DNA repair. This could reduce the effectiveness of both cisplatin and etoposide (VP-16). Previous studies on human neuroblastoma cells have shown a relationship between N-myc copy number and cisplatin sensitivity. We now report the response to VP-16 treatment of five human neuroblastoma cell lines with a range of N-myc gene copy numbers. After exposure of cells to drug for 24 hours, survival curves were constructed from clonogenic assay data and the iso-effective dose (the dose required to produce 1 log cell kill) was derived. The relationship between N-myc copy number or expression and response to VP-16 was assessed. A significant correlation was established between VP-16 resistance and copy number (r = 0.82; P < 0.05). However, no association was found between N-myc expression and isoeffective dose of VP-16. These results indicate that N-myc amplification may be responsible for treatment failure in those patients receiving cisplatin or VP-16.

Antineoplastic Agents, Phytogenic↗
PubMed1996

Isolation of CD4+ and CD8+ T-Cell Clones from Mice Immunized with Synthetic Peptides on Splenic Dendritic Cells

Splenic dendritic cells (DC) express high levels of MHC, co-stimulator, and adhesion molecules and have been shown to be extremely potent antigen-presenting cells for both CD4(+) and CD8(+) T-cell responses. Previous studies have shown that murine DC can be loaded with exogenous antigens and used to prime CD4(+), Class II-restricted T-cell responses in vivo. This article describes protocols for immunization using DC loaded with peptides bound to Class I or Class II molecules and for the derivation and characterization of CD4(+) and CD8(+) antigen-specific T-cell lines and clones. The rationale for using DC as antigen-presenting cells is discussed, together with the advantages and disadvantages of these cells compared with more conventional methods of immunization.

Journal Article↗
PubMed1994

N-myc gene copy number in neuroblastoma cell lines and resistance to experimental treatment.

The N-myc oncogene is amplified in approximately 30% of neuroblastomas. It is well established that cases of neuroblastoma with amplified N-myc have markedly poorer prognosis than those in which N-myc copy number is not elevated. The mechanism for this association is not known but may be related to cellular resistance to radiation or cytotoxic drugs. Seven human neuroblastoma cell lines were used to investigate the relationship between N-myc copy number or expression and sensitivity to ionising radiation and to cisplatin. N-myc copy number was assessed by Southern blotting and hybridisation using the p-Nb1 probe. The signal produced by DNA from the cell lines was compared with that of single copy N-myc from normal human placental DNA. A range of N-myc copy numbers from 1 to 800 was found. Expression levels of N-myc mRNA were compared by "dot blotting" and subsequent hybridisation to the p-Nb1 probe. Radiosensitivity was assessed by surviving fraction at 2 Gy (SF2) following 60Co gamma irradiation. Values ranged from 0.13 to 0.52. Sensitivity to cisplatin was indicated by comparison of isoeffective concentrations (concentration required to produce 1 log cell kill). These ranged from 7.5 to 13 microM. Cisplatin studies showed a correlation between N-myc copy number (though not expression) and resistance to this drug. If this relationship is causal it may explain why treatment fails in those patients with an elevated N-myc copy number. However, no correlation was found between N-myc copy number or expression and sensitivity to radiation. It is possible that N-myc amplification confers resistance to some but not all treatments used in the therapy of neuroblastoma. Further investigations along these lines may lead to the identification of agents which are most appropriate for the treatment of neuroblastoma with amplified N-myc gene.

Blotting, Southern↗