Reversal of CPT-11 resistance of lung cancer cells by adenovirus-mediated gene transfer of the human carboxylesterase cDNA

To evaluate the concept that transfer of the human carboxylesterase (CE) gene will overcome the drug resistance of a solid tumor to CPT-11 (irinotecan), we used an adenovirus vector (AdCMV.CE) carrying human CE cDNA to infect CPT-11-resistant A549 human adenocarcinoma cells (A549/CPT) in vitro and in vivo and evaluated cell growth over time. The A549/CPT cells, selected by stepwise and continuous exposure of parental A549 cells to CPT-11 over 10 months, had a 6-fold resistance to CPT-11 and 42% CE activity in comparison with parental A549 cells. AdCMV.CE infection resulted in an increase in functional CE protein in resistant cells in vitro that was sufficient to convert CPT-11 to its active metabolite, SN-38, and effectively suppressed resistant cell growth in vitro in the presence of CPT-11. When AdCMV.CE was directly injected into established s.c. resistant A549-based tumors in nude mice receiving CPT-11, there was a 1.8-fold reduction in tumor size at day 20 compared to that of controls (P < 0.05). These observations suggest that adenovirus-mediated gene transfer of the human CE gene and concomitant administration of CPT-11 may have potential as a strategy for local control of acquired CPT-11 resistance of solid tumors.     

Treatment outcome with radiation therapy after breast augmentation or reconstruction in patients with primary breast carcinoma

BACKGROUND: Analyses were performed to determine local control and cosmetic outcome of breast carcinoma patients with prosthetically augmented or reconstructed breasts who had received radiation therapy (RT). METHODS: Twenty-one newly diagnosed breast carcinoma patients with prosthetically augmented or reconstructed breasts were treated with external beam RT. All patients received whole breast RT (median dose, 50.4 gray [Gy]) and 19 were boosted to a median dose of 60.4 Gy. A median dose of 50.4 Gy was delivered to the regional lymph nodes in 12 patients. Tissue equivalent bolus material was used in six patients. Seventeen patients received adjuvant systemic therapy. Cosmetic results were evaluated at 3-6-month intervals. RESULTS: With a median follow-up of 32 months, good/excellent cosmetic results were observed in 71% of patients (100% in those with augmented breasts and 54% in those with reconstructed breasts). Four patients (19%) with fair/poor cosmetic outcomes required implant removal and/or revision. Multiple clinical and treatment-related factors were analyzed for their impact on cosmetic outcome. A worsened cosmetic result was observed with increasing stage (P = 0.076), breast reconstruction (vs. augmentation) (P = 0.030), and bolus application (P = 0.016). All patients with fair/poor cosmetic outcomes had time intervals from implant insertion to RT ranging from 53-213 days. Two patients developed an isolated local recurrence within the augmented breast. CONCLUSIONS: Patients with prosthetically augmented breasts can undergo RT and expect good/excellent cosmetic results. Patients with reconstructed breasts are at a significantly greater risk for cosmetic failure. This risk may be related to the higher percentage of patients with advanced disease, those who received bolus application, and those who received earlier delivery of RT (after the cosmetic procedure) in reconstructed breasts.     

Discovery and evaluation of a series of 3-acylindole imidazopyridine platelet-activating factor antagonists

Studies conducted with the goal of discovering a second-generation platelet-activating factor (PAF) antagonist have identified a novel class of potent and orally active antagonists which have high aqueous solubility and long duration of action in animal models. The compounds arose from the combination of the lipophilic indole portion of Abbott's first-generation PAF antagonist ABT-299 (2) with the methylimidazopyridine heterocycle moiety of British Biotechnology's BB-882 (1) and possess the positive attributes of both of these clinical candidates. Structure-activity relationship (SAR) studies indicated that modification of the indole and benzoyl spacer of lead compound 7b gave analogues that were more potent, longer-lived, and bioavailable and resulted in the identification of 1-(N, N-dimethylcarbamoyl)-4-ethynyl-3-[3-fluoro-4-[(1H-2-methylimidazo[4,5-c] pyrid-1-yl)methyl]benzoyl]indole hydrochloride (ABT-491, 22 m.HCl) which has been evaluated extensively and is currently in clinical development.     

Orthotopic heart transplantation in a transgenic pig-to-primate model

BACKGROUND: Previous studies demonstrated that hearts from transgenic pigs expressing human decay-accelerating factor (hDAF) were not hyperacutely rejected when transplanted heterotopically into the abdomen of cynomolgus monkeys. This study examines orthotopic transplantation of hDAF transgenic pig hearts into baboon recipients. METHODS: Orthotopic xenogeneic heart transplantation was performed using piglets, transgenic for hDAF, as donors. Ten baboons were used as recipients and were immunosuppressed with a combination of cyclophosphamide, cyclosporine, and steroids. RESULTS: Five grafts failed within 18 hr without any histological signs of hyperacute rejection. Pulmonary artery thrombosis induced by a size mismatch was observed in two of these animals. The other three recipients died because of failure to produce even a low cardiac output and/or dysrhythmia. The remaining five animals survived between four and nine days. One animal died of bronchopneumonia on day 4. Three xenografts stopped beating on day 5 due to acute vascular rejection. The longest survivor was killed on day 9 with a beating, histologically normal xenograft, because of pancytopenia. CONCLUSIONS: The results reported here demonstrate that hDAF transgenic pig hearts are not hyperacutely rejected when transplanted into baboon recipients. Orthotopically transplanted transgenic pig hearts are capable of maintaining cardiac output in baboons. An optimum immunosuppressive regimen is the subject of ongoing research.     

Topographical organization of inferior olive cells projecting to translation and rotation zones in the vestibulocerebellum of pigeons

Previous electrophysiological studies in pigeons have shown that the vestibulocerebellum can be divided into two parasagittal zones based on responses to optic flow stimuli. The medial zone responds best to optic flow resulting from self-translation, whereas the lateral zone responds best to optic flow resulting from self-rotation. This information arrives from the retina via a projection from the accessory optic system to the medial column of the inferior olive. In this study we investigated inferior olive projections to translational and rotational zones of the vestibulocerebellum using the retrograde tracer cholera toxin subunit B. Extracellular recordings of Purkinje cell activity (complex spikes) in response to large-field visual stimuli were used to identify the injection sites. We found a distinct segregation of inferior olive cells projecting to translational and rotational zones of the vestibulocerebellum. Translation zone injections resulted in retrogradely labeled cells in the ventrolateral area of the medial column, whereas rotation zone injections resulted in retrogradely labeled cells in the dorsomedial region of the medial column. Motion of any object through space, including self-motion of organisms, can be described with reference to translation and rotation in three-dimensional space. Our results show that, in pigeons, the brainstem visual systems responsible for detecting optic flow are segregated into channels responsible for the analysis of translational and rotational optic flow in the inferior olive, which is only two synapses from the retina.     

Melanoma-specific cytotoxicity induced by a tyrosinase promoter-enhancer/herpes simplex virus thymidine kinase adenovirus

BACKGROUND: High blood pressure is a major risk factor for coronary artery disease, kidney disease, and stroke. More people are aware of treating and controlling their blood pressure, but overall control rates are low and the incidence of hypertension-related morbidity and mortality remains high. METHODS: The National Heart, Lung, and Blood Institute released The Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI) as the most recent national guideline to hypertension control for primary care clinicians. RESULTS: JNC VI identifies 10 hypertension-related public health challenges: (1) prevent the rise of blood pressure; (2) decrease prevalence of hypertension; (3) increase awareness and detection of hypertension; (4) improve control of hypertension; (5) reduce cardiovascular risks; (6) increase recognition of importance of isolated systolic hypertension; (7) improve recognition of importance of high-normal blood pressure; (8) reduce ethnic, socioeconomic, and regional variations; (9) improve treatment; and (10) enhance community programs. CONCLUSIONS: The eye is a target organ and retinopathy is a frequent complication--as well as a prognostic indicator--of sustained hypertension. As part of a multidisciplinary team approach, the optometrist assumes a significant role in the prevention, detection, evaluation, and treatment of high blood pressure and its associated morbidities.     

N2- and C8-substituted oligodeoxynucleotides with enhanced thrombin inhibitory activity in vitro and in vivo

2'-Deoxyguanosine (G) analogues carrying various hydrophobic substituents in the N2 and C8 positions were synthesized and introduced through solid-phase synthesis into 15-mer oligodeoxynucleotide, GGTTGGTGTGGTTGG, which forms a chairlike structure consisting of two G-tetrads and is a potent thrombin inhibitor. The effects of the substitutions at N2 and C8 of the G-tetrad-forming G residues on the thrombin inhibitory activity are relatively small, suggesting that these substitutions cause relatively small perturbations on the chairlike structure formed by the oligodeoxynucleotide. Introduction of a benzyl group into N2 of G6 and G11 and naphthylmethyl groups into N2 of G6 increased the thrombin inhibitory activity, whereas other substituents in these positions had almost no effect or decreased the activity. Particularly, the oligodeoxynucleotide carrying a 1-naphthylmethyl group in the N2 position of G6 showed an increase in activity by about 60% both in vitro and in vivo. Substitutions on the N2 position of other G residues had little effect or decreased the activity. Introduction of a relatively small group, such as methyl and propynyl, into the C8 positions of G1, G5, G10, and G14 increased the activity, presumably due to the stabilization of a chairlike structure, whereas introduction of a large substituent group, phenylethynyl, decreased the activity, probably due to the steric hindrance.     

Radiobiologically based assessments of the net costs of fractionated focal radiotherapy

PURPOSE: To assess the potential changes in the net costs of focal radiotherapy techniques at differing doses per fraction and interfraction intervals. METHODS: Linear quadratic radiobiological modeling is used with appropriate variations in the radiosensitivity and tumor cell proliferation parameters. The notional cost of treatment is calculated from the number of fractions, cost per fraction and the cost of treatment failure, which is itself related to (1-TCP) where TCP is the tumor cure probability. Additional Monte Carlo calculations from ranges of radiobiological parameters have been used to simulate the cost of treatment of tumor populations. RESULTS: The optimum dose per fraction (and optimum overall cost) for conventional (nonfocal) radiotherapy is generally at low doses of around 2 Gy per fraction. The use of hyperfractionated and accelerated radiotherapy in addition to focal radiotherapy techniques appear to be indicated for more radioresistant tumors and if tumor proliferation is extremely rapid, but the need for treatment acceleration is much reduced where effective focal techniques are used. CONCLUSIONS: Radiobiological and economic modeling can be used to guide clinical choices of dose fractionation techniques providing the key radiobiological parameters are known or if the ranges of likely parameters in a tumor population are known. Focal radiotherapy, by the introduction of changes in the physical dose distribution, produces an upward shift in the optimum dose per fraction and a reduced dependency on overall treatment time.