Lentiviral vectors for gene therapy of cystic fibrosis

A replication-defective vector based on human immunodeficiency virus (HIV) was evaluated for gene transfer directed to the lung. The tropism of this vector has been expanded through the incorporation of the vesticular stomatitis virus G protein into its envelope. The HIV vector effectively transduced nondividing airway epithelial cells in vitro whereas a murine-based retroviral vector did not. Experiments in a human bronchial xenograft model demonstrated high-level gene transduction with a cystic fibrosis transmembrane conductance regulator (CFTR) HIV vector into undifferentiated, cystic fibrosis (CF)-derived cells of the xenograft. CFTR expression was stable and capable of functional correction of the CF defect after the graft matured. The HIV vector did not effectively transduce cells of the xenograft when instilled after the epithelium had differentiated. This block to transduction appears to be at the level of entry, although post entry restrictions cannot be ruled out. Further development of this vector system for CF gene therapy should focus on a better understanding of potential entry and post entry blocks.     

Double-blind, placebo-controlled evaluation of sublingual immunotherapy with standardized olive pollen extract in pediatric patients with allergic rhinoconjunctivitis and mild asthma due to olive pollen sensitization

For evaluation of the efficacy and the safety of specific sublingual immunotherapy with high allergen dose, 66 children with seasonal asthma, rhinitis, and conjunctivitis due to sensitization to olive pollen were enrolled in a double-blind, randomized, placebo-controlled study between October 1994 and October 1996 in Greece. Thirty-four patients were randomly allocated to the active group, and 32 received placebo. Immunotherapy consisted of olive-allergen extracts (Stallergènes SA) administered sublingually pre- and coseasonally from January to July for 2 consecutive years. Serial concentrations from 1 to 300 IR. were used up to the maintenance dose of 20 drops of 300 IR daily. The cumulative dose for each patient was 300 times higher than in parenteral immunotherapy, and the cumulative dose of the major allergen Ole e 1 was 8.1 mg/2 years. The patients were assessed by clinical parameters (symptom and medication scores from patients' daily diaries) and immunologic measurements (specific IgE, IgG4, eosinophil cationic protein [ECP]) were performed. The actively treated patients had a significantly lower score for dyspnea (P<0.04 during the first season; P<0.03 during the second season). At the pollinic peak during the second year, a lower score of conjunctivitis was recorded (P<0.05) in the actively treated patients. The analysis of intragroup evolution showed that the total score of rhinitis increased significantly during the pollinic peak in the group under placebo, whereas there was no symptomatic peak for the same period in the group under active treatment. However, the difference between the groups was not significant. The medication score did not differ significantly between the groups. Oral steroids were the only variables with a P value near the significance level (P=0.06) in favor of the actively treated group. A significant decrease in skin reactivity was recorded in the active group after 2 years of treatment. No significant variation in specific IgE and IgG4 was detected. A significantly lower level of serum ECP was observed at the pollinic peak in the actively treated patients during the first pollen season (P=0.01), but this was not confirmed the second year when the ECP levels doubled in both groups without correlation to the clinical findings. Tolerance was excellent with only a few minor side-effects reported. In conclusion, high-dose specific sublingual immunotherapy appears to be safe and effective in improving mild seasonal asthma and conjunctivitis linked to olive-pollen sensitization.     

Plasma lipids, lipoproteins, and triglyceride turnover in eu- and hypo-thyroid rats and rats on a hypocaloric diet

Lipid and lipoprotein concentration, and triglyceride turnover were studied in control, thyroidectomized, and pair-fed control rats (pair-fed to match the food intake of the thyroidectomized rats). Thyroidectomy induced a significant increase in plasma cholesterol (and low density lipoprotein) concentrations and a decrease in plasma triglyceride (and very low density lipoprotein) concentrations. Changes in similar direction but of smaller magnitude were observed in the plasma of the pair-fed control rats. To further investigate triglyceride metabolism in these three groups of animals, triglyceride turnover was studied in fasted, unrestrained, and unanesthetized rats, following injection of [2-3H]glycerol. Peak incorporation of [2-3H]glycerol into plasma triglyceride occurred in all three groups of animals at 25 min after precursor administration, although the maximal incorporation was substantially lower in the thyroidectomized group than in either of the control groups. Thereafter, plasma triglyceride radioactivity decayed monoexponentially with a half-life of 24 +/- 1 min for both normal and pair-fed control rats, compared with the half-life of 41 +/- 3 min observed in the thyroidectomized rats. The calculated apparent fractional catabolic rates were thus 0.029 min-1 for both control groups and only 0.017 min-1 for the thyroidectomized animals. The apparent total catabolic rates of plasma triglyceride were 299 +/- 11, 138 +/- 11, and 48 +/- 4 micrograms triglyceride . min-1 for the normal controls, pair-fed controls, and thyroidectomized rats, respectively. These data further emphasize the importance of thyroid hormones in regulating plasma lipid and lipoprotein metabolism and, specifically, indicate that hypothyroidism results in a reduction of triglyceride secretion into, and the removal from, circulation. Furthermore, evidence was presented that the decreased caloric intake of the hypothyroid animals cannot, in itself, account for this observation.     

Behavior of N-acylated daunorubicins in MDR1 gene transfected and parental cells

The substrate specificity of the P-glycoprotein (P-170), a multidrug transporter, was studied using N-acylated daunorubicin derivatives and four MDR1 cDNA transfected cell lines. Results showed that N-acetyl-daunorubicin is a substrate, but the longer fatty acid derivatives, N-octanoyl and N-dodecanoyl daunorubicins, are not. This conclusion was reached by flow cytometric drug uptake assay, cell proliferation assays, and confocal microscopy. It was concluded that the longer fatty acid derivatives interact with plasma membranes in a way that affected P-glycoprotein function.     

Radiation-induced enhanced proliferation of human squamous cancer cells in vitro: a release from inhibition by epidermal growth factor

Ionizing radiation is believed to stimulate the repopulation of squamous carcinoma cells that survive the early portion of a fractionated course of radiotherapy. To characterize any intrinsic radiation-induced adaptive response and to examine whether epidermal growth factor (EGF) influences this response, A431 and 183A cells were irradiated with repeated daily exposures of 0.5-0.75 Gy and then grown in monolayer culture for 7 days with or without EGF at a 1 ng/ml concentration. Cell numbers were quantified using a microtiter dye-reduction assay. EGF alone caused approximately 70% and 30% growth inhibition of human SC A431 and 183A cells, respectively. Although radiation alone did not affect proliferative rates in these conditions, radiation eliminated the EGF-related growth inhibition in both cell lines. This effect was dose dependent in single radiation exposure experiments. Cell cycle analyses indicated that EGF initially promoted entry into S-phase 3 days after treatment but caused a G1-S block after 7 days. Treatment with radiation recruited cells into S-phase and G2-M, an effect which was sustained 7 days after treatment, overriding the influence of EGF. Radiation-induced modulation of the response of human squamous carcinoma cells to EGF in vitro after single and repeated radiation exposures suggests a proliferation response that may underlie enhanced repopulation of tumor clonogens in vivo.     

Clinical experience with fludarabine and its immunosuppressive effects in pretreated chronic lymphocytic leukemias and low-grade lymphomas

Fludarabine monophosphate (FAMP) is a new adenine nucleoside analogue with a promising efficacy in B-cell chronic lymphocytic leukemia (B-CLL) and low-grade non-Hodgkin lymphomas (NHLs). Here, the clinical experience and side effects with FAMP are reported in 77 patients with pretreated CLL (59 B-CLL, 2 T-CLL) and low-grade NHLs (9 immunocytic lymphomas including 5 Waldenstr?m's macroglobulinaemia, 2 centrocytic (cc) and 5 centroblastic-centrocytic (cb-cc) NHLs). 70/77 patients are evaluable for response. All except 8 patients were pretreated with one to four different regimens and had progressive disease. FAMP was administered at a dosage of 25 mg/m2 daily for 5 days as 30 minute infusion every fifth week. Partial (PR) or complete remission (CR) was achieved in 38/56 (68%) and 3/56 (5%) of evaluable patients with CLL, respectively. In 7/8 (1 x CR, 6 x PR) evaluable patients with immunocytic lymphoma and in 3/6 (3 x PR) patients with cc or cb-cc lymphoma remissions were obtained. The probability of progression-free survival was 66% and the event-free survival was 25% and 22% at 12 and 18 months. The median progression-free survival until relapse or death, however, was only 7 months (2-20+). Major toxic effects included infections in 22 patients (grade 3 and 4 WHO), granulocytopenia (mainly grade 3) and nausea in 8 patients (mainly grade 1). 19/22 patients were in PR at the time of occurrence of infectious complications. Meanwhile, 14 patients died due to septicaemia, pneumonia or other infections. Nine patients developed severe septicaemia, 4 patients had pneumocystis carinii or aspergillus pneumonias. The high infection rate may not only be due to hypogammaglobulinaemia and granulocytopenia induced by FAMP but also to a remarkable decrease of CD4+ cells from a median of 2479 to 241 CD4+ cells/microliters after 6 cycles of FAMP. In one case a tumor lysis syndrome was observed. No CNS toxicity was noted. It is concluded that FAMP is effective even in patients with advanced CLL and low-grade NHLs refractory to multiple chemotherapy regimens. However, FAMP has a marked suppressive effect on granulocytes and T-lymphocytes, predominantly CD4+ lymphocytes.