[Respiratory physiotherapy in private practice: Interest and prescription modalities]

INTRODUCTION

Respiratory diseases represent a major public health issue and impact both quality of life and life expectancy of the patients.

STATE OF ART

Several interventions used in respiratory physiotherapy have been shown to reduce dyspnoea, improve quality of life and reduce hospitalisation in many respiratory diseases. However, respiratory physiotherapy remains poorly known to the medical community and may be under-prescribed.

PERSPECTIVES

In order to improve the interdisciplinarity around the patient with respiratory impairment, we describe the interests and prescription modalities of liberal respiratory physiotherapy. In the context of respiratory physiotherapy acts, the precision of drafting prescription directly conditions the means implemented by the physiotherapist regarding care provided to the patient.

CONCLUSION

The increased knowledge of prescribers, both concerning the prescription methods and the precise content of the rehabilitation sessions is one of the keys to their success.

Prognostic impact of pretreatment cell-free DNA concentration in newly diagnosed peripheral T-cell lymphomas

Peripheral T-cell lymphomas (PTCLs) have a poor prognosis and, to date, there are no reliable predictive biomarkers of response. In this work we explored the prognostic impact of cell-free DNA (cfDNA) concentration in 75 newly diagnosed patients enrolled in a prospective multicenter study. Pre-treatment cfDNA was strongly associated with clinical risk factors and was identified as a superior predictor for shorter progression-free survival in multivariable analysis, outweighing canonical risk parameters. Furthermore, we identified a cfDNA value above which survival worsens. In conclusion, pre-treatment cfDNA concentration represents an easily usable predictive biomarker that is highly associated with survival of PTCL patients.

SARS-CoV-2 hampers dopamine production in iPSC-derived dopaminergic neurons

An increasing number of patients experiences prolonged symptoms, whose profile and timeline remain uncertain, a condition that has been defined as post COVID. The majority of recovered hospitalized patients manifests at least one persistent symptom even sixty days after the first clinical manifestation's onset. Particularly, in light of the COVID-19-related symptomatology, it has been hypothesized that SARS-CoV-2 might affect the dopamine pathway. However, no scientific evidence has been produced so far. To this end, human iPSC-derived dopaminergic neurons were infected with EU, Delta and Omicron SARS-CoV-2 variants. The infection with EU and Delta variants, but not with Omicron, results in a reduced intracellular content and extracellular release of dopamine. Indeed, the tyrosine hydroxylase was found to be significantly upregulated at the mRNA level, while being greatly reduced at the protein level. The major downstream synthetic enzyme DOPA-decarboxylase and the dopamine transporter were significantly downregulated both at the mRNA and protein level. Notably, in vitro SARS-CoV-2 infection was also associated with an altered MAP2 and TAU expression and with an increased presence of neuronal stress markers. These preliminary observations suggest that the dopamine metabolism and production are affected by SARS-CoV-2, partially explaining some of the neurological symptoms manifested.

β-Glucocerebrosidase Deficiency Activates an Aberrant Lysosome-Plasma Membrane Axis Responsible for the Onset of Neurodegeneration

β-glucocerebrosidase is a lysosomal hydrolase involved in the catabolism of the sphingolipid glucosylceramide. Biallelic loss of function mutations in this enzyme are responsible for the onset of Gaucher disease, while monoallelic β-glucocerebrosidase mutations represent the first genetic risk factor for Parkinson’s disease. Despite this evidence, the molecular mechanism linking the impairment in β-glucocerebrosidase activity with the onset of neurodegeneration in still unknown. In this frame, we developed two in vitro neuronal models of β-glucocerebrosidase deficiency, represented by mouse cerebellar granule neurons and human-induced pluripotent stem cells-derived dopaminergic neurons treated with the specific β-glucocerebrosidase inhibitor conduritol B epoxide. Neurons deficient for β-glucocerebrosidase activity showed a lysosomal accumulation of glucosylceramide and the onset of neuronal damage. Moreover, we found that neurons react to the lysosomal impairment by the induction of their biogenesis and exocytosis. This latter event was responsible for glucosylceramide accumulation also at the plasma membrane level, with an alteration in lipid and protein composition of specific signaling microdomains. Collectively, our data suggest that β-glucocerebrosidase loss of function impairs the lysosomal compartment, establishing a lysosome–plasma membrane axis responsible for modifications in the plasma membrane architecture and possible alterations of intracellular signaling pathways, leading to neuronal damage.

Quantization of CD34+ Peripheral Blood Hematopoietic Progenitors for Autografting in Cancer Patients

After myeloablative regimens, combined reinfusion of peripheral blood hematopoietic circulating progenitor cells (CPC) and bone marrow, yields a very rapid hematopoietic recovery. Therefore, based on the knowledge that CPC express the CD34 and CD33 differentiation antigen, we have developed a direct immunofluorescence flow cytometry assay to detect the peak of CPC in the peripheral blood of patients treated with high dose chemotherapy and growth factors. This assay, compared to CFU-GM assay, has the following advantages: 1) easy to do 2) standardized method 3) real time information on CPC number. This work illustrates the practical aspects of this assay and substantiate the widespread use of the CD34/33 flow cytometry assay to guide harvesting of circulating hematopoietic progenitors for autologous transplantation.

High-dose sequential chemotherapy (HDS) versus PEB chemotherapy as first-line treatment of patients with poor prognosis germ-cell tumors: mature results of an Italian randomized phase II study

BACKGROUND

In the late 1990s, the use of high-dose chemotherapy (HDCT) and stem-cell rescue held promise for patients with advanced and poor prognosis germ-cell tumors (GCT). We started a randomized phase II trial to assess the efficacy of sequential HDCT compared with cisplatin, etoposide, and bleomycin (PEB).

PATIENTS AND METHODS

Patients were randomly assigned to receive four cycles of PEB every 3 weeks or two cycles of PEB followed by a high-dose sequence (HDS) comprising HD-cyclophosphamide (7.0 g/m(2)), 2 courses of cisplatin and HD-etoposide (2.4 g/m(2)) with stem-cell support, and a single course of HD-carboplatin [area under the curve (AUC) 27 mg/ml × min] with autologous stem-cell transplant. Postchemotherapy surgery was planned on responding residual disease in both arms. The primary end point was progression-free survival (PFS). The study was designed to detect a 30% improvement of 5-year PFS (from 40% to 70%), with 80% power and two-sided α at 5%.

RESULTS

From December 1996 to March 2007, 85 patients were randomized: 43 in PEB and 42 in HDS arm. Median follow-up was 114.2 months [interquartile range (IQR): 87.7-165.8]. Complete or partial response with normal markers (PRm-) were obtained in 28 (65.1%) and 29 (69.1%) patients, respectively. Five-year PFS was 55.8% [95% confidence interval (CI) 42.8-72.8] and 54.8% (95% CI 41.6%-72.1%) in PEB and HDS arm, respectively (log-rank test P = 0.726). Five-year overall survival was 62.8% (95% CI 49.9-79.0) and 59.3% (95% CI 46.1-76.3). One toxic death (PEB arm) was recorded.

CONCLUSIONS

The study failed to meet the primary end point. Furthermore, survival estimates of conventional-dose chemotherapy higher than expected should be accounted for and will likely limit further improvements in the first-line setting. CLINICALTRIALS.GOV: NCT02161692.

Immunization of indolent non-Hodgkin’s lymphoma patients with autologous monocyte-derived dendritic cells loaded with heat shocked and killed autologous tumor cells: A phase I study

3006

Background: To evaluate the safety and tolerability of vaccination with DCs loaded with killed tumor cells, 18 patients with measurable relapse/refractory follicular (12) and lymphoplasmocytoid (6) lymphoma have been enrolled in a phase I study. Methods: Each patient received at 2-weekly intervals 4 SC injections of 50x10e6 tumor-loaded DCs. Immature DCs were generated by 5-days culture of autologous monocytes in the presence of IL-4 and GM-CSF. Autologous CD19+ tumor cells, harvested from lymph nodes (12) and/or peripheral blood (6), were heat shocked and then irradiated by UVC. DCs were loaded for 48 hrs with killed tumor cells and then were cultured for 12 hrs in the presence of TNF-a. Median prior number of treatment regimens was 2 (range 1–5) comprising 4 patients treated with high-dose chemotherapy. The vaccination was started at least 6-months after the last chemotherapy treatment. Results: All patients were evaluable for toxicity and for efficacy with a median follow-up of 30.5 months (range 18–45 months). Overall, vaccinations were well tolerated and no autoimmune reactions were observed. Mild erythema in the site of injection developed in the majority of patients (12/18), but only in 2 cases induration and extended erythema was observed. Six of 18 patients had objective responses. Three patients had partial responses (PR). One is still in PR and the others have a PR lasting 7 and 15 months, respectively. Three patients had complete remission (CR) and are are still in CR with a mean CR duration of 17 months. The remaining 12 patients had stable disease (8) or progressive disease (4). In the patients in PR, a significant increase of anti autologous tumor-specific T cells, evaluated by ELISPOT assay for IFN-γ, was observed in the post-vaccination lymph nodes, compared to the tissue sample taken before vaccination. In addition, in the responding patients a significant reduction in peripheral blood of FoxP3+ regulatory T cells was observed. Conclusion: The injection of DCs loaded with killed tumor cells is a well-tolerated procedure achieving clinical and immunological responses also in the presence of significant tumor burden.

No significant financial relationships to disclose.

Prolonged survival in poor-risk diffuse large B-cell lymphoma following front-line treatment with rituximab-supplemented, early-intensified chemotherapy with multiple autologous hematopoietic stem cell support: a multicenter study by GITIL (Gruppo Italiano Terapie Innovative nei Linfomi)

A prospective multicenter program was performed to evaluate the combination of rituximab and high-dose (hd) sequential chemotherapy delivered with multiple autologous peripheral blood progenitor cell (PBPC) support (R-HDS-maps regimen) in previously untreated patients with diffuse large B-cell lymphoma (DLB-CL) and age-adjusted International Prognostic Score (aaIPI) score 2-3. R-HDS-maps includes: (i) three APO courses; (ii) sequential administration of hd-cyclophosphamide (CY), hd-Ara-C, both supplemented with rituximab, hd-etoposide/cisplatin, PBPC harvests, following hd-CY and hd-Ara-C; (iii) hd-mitoxantrone (hd-Mito)/L-Pam + 2 further rituximab doses; (iv) involved-field radiotherapy. PBPC rescue was scheduled following Ara-C, etoposide/cisplatin and Mito/L-Pam. Between 1999 and 2004, 112 consecutive patients aged <65 years (74 score 2, 38 score 3) entered the study protocol. There were five early and two late toxic deaths. Overall 90 patients (80%) reached clinical remission (CR); at a median 48 months follow-up, 87 (78%) patients are alive, 82 (73%) in continuous CR, with 4 year overall survival (OS) and event-free survival (EFS) projections of 76% (CI 68-85%) and 73% (CI 64-81%), respectively. There were no significant differences in OS and EFS between subgroups with Germinal-Center and Activated B-cell phenotype. Thus, life expectancy of younger patients with aaIPI 2-3 DLB-CL is improved with the early administration of rituximab-supplemented intensive chemotherapy compared with the poor outcome following conventional chemotherapy.

[Primary lymphoma of the uterus. A case report]

Primary uterine lymphoma is a rare gynecologic cancer. Usually it involves rather the cervix than the uterine corpus and most of them are B-cell lymphomas. We describe a case of a 43-year old, asymptomatic patient, arrived observed for ureter dilatation due to a pelvic mass diagnosed by urography. The history of the patient, the presurgical clinical and radiological findings did not reveal any sign of uterine lymphoma. These difficulties show that at present it is not possible to make any prevention for this kind of cancer. The diagnosis of lymphoma was done at frozen section during surgery, but the final diagnosis is reached after two weeks. The patient underwent a debulking surgery of the mass, ureter cleaning with introduction of ureteral stent and a node sampling was done. The correct staging and the surgical and/or medical management of this cancer (not yet standardized) are the most important factors to improve the survival of these patients.

High-dose ara-C with autologous peripheral blood progenitor cell support induces a marked progenitor cell mobilization: an indication for patients at risk for low mobilization

A high-dose (HD) chemotherapy scheme was designed for the collection of large numbers of peripheral blood progenitor cells (PBPC) in lymphoma patients who were candidates for myeloablative therapy with autograft. The scheme included the sequential administration of HD cyclophosphamide (CY) (7 g/m(2)) and HD ara-C (2 g/m(2) twice a day for 6 consecutive days), followed by final consolidation with PBPC autograft. PBPC harvests were scheduled following both HD CY and HD ara-C. To minimize hematologic toxicity, small aliquots of PBPC (<or=3 x 10(6) CD34(+) cells/kg) collected following HD CY were reinfused following HD ara-C. The treatment was delivered to 112 patients (median age: 43 years) with lymphoid malignancies (107 non-Hodgkin's lymphoma, four Hodgkin's lymphoma, one amyloidosis); 75 patients were at disease onset, whereas 37 had relapsed or were refractory after first-line conventional therapy. PBPC mobilization was assessed in terms of peak values of circulating CD34(+) cells/microl, as well as total CD34(+) cells/kg collected. In a few patients CFU-GM/kg were also evaluated. At the time of maximal mobilization following HD CY, 93 'high-mobilizer' patients had >20 circulating CD34(+) cells/microl, whereas the remaining 19 'low-mobilizer' patients did not reach this cut-off value. In spite of poor mobilization after HD CY, 16 out of 19 low mobilizers provided good harvests following HD ara-C; overall, median collected CD34(+) cells x 10(6)/kg were 1.4 (0-3.1) and 10.2 (0-37) after HD CY and HD ara-C, respectively (P = 0.00007). Similar patterns were observed when PBPC were evaluated by CFU-GM/kg. Complete and durable hemopoietic reconstitution followed autograft with post HD ara-C PBPC. Within the high-mobilizer group, 88 patients received HD ara-C and 79 (90%) still showed high mobilization; overall, median collected CD34(+)cells x 10(6)/kg were 17.8 (range 3-94) and 19 (range 0-107) after HD CY and HD ara-C respectively (P = NS). Thus, the scheme allowed sufficient PBPC collections for autografting in low mobilizer patients; in addition, the scheme could be considered whenever extensive chemotherapy debulking is needed prior to PBPC collection.

Rituximab: enhancing stem cell transplantation in mantle cell lymphoma

Mantle cell lymphoma (MCL) responds poorly to standard chemotherapy regimens used in non-Hodgkin's lymphoma. As a result, a combination of high-dose chemotherapy (HDT) with autologous stem cell transplantation (ASCT) is being investigated in patients with MCL. So far, however, there is no evidence for long-term remission -- believed, in part, to be due to contamination of the transfusion product with residual cancer cells. Many ex-vivo purging methods have been developed to remove tumour cells, but these are complicated, time-consuming and expensive. This study describes an in vivo purging method using rituximab to produce a tumour-free stem cell product for re-infusion following HDT. The regimen is split into a purging phase and a myeloablative phase, which together consist of four-step high-dose sequential chemotherapy (sHDT) and six infusions of rituximab immunotherapy. The sHDT comprises cyclophosphamide, cytosine arabinoside, melphalan and mitoxantrone plus melphalan. There are two separate stem cell harvests and three reinfusions. In a pilot study 28 patients with untreated MCL received standard chemotherapy followed by sHDT with rituximab in vivo purging. Preliminary results indicate that in PCR analyses of leukaphereses from 20 assessable patients, 100% lymphoma-negative harvests were achieved following in vivo purging. PCR analyses of the bone marrow following the four-step high-dose regimen with purging and transplantation showed that all patients achieved molecular remission. After a median follow-up of 22 months (range 10-42 months), two patients had died while 26 were alive and disease free. This method allows efficient in vivo purging in the context of an effective chemotherapy regimen and may have a role as first-line therapy in MCL patients who respond poorly to standard treatment.

High-dose ifosfamide and vinorelbine as salvage therapy for relapsed or refractory Hodgkin's disease

In an effort to improve results in patients with relapsed or refractory Hodgkin's disease (HD), an intensive regimen combining vinorelbine (25 mg/m2 i.v. days 1 and 5) and high-doses of ifosfamide (3000 mg/m2/d, days 1-4 by continuous infusion) with mesna uroprotection and G-CSF support was designed. Forty-seven patients were treated; 14 had failure to initial induction therapy and 33 had disease relapsed from an initial response. The response rate was 83%, with 21 complete (45%, CR) and 18 partial remissions (38%, PR). Partial response was achieved after a median of two cycles (range 1-3) and CR after a median of six cycles (range 2-10). At the end of ifosfamide and vinorelbine, 10 patients in CR, one in PR, and one with stable disease also received radiotherapy to nodal sites of relapse. Eleven patients who had undergone peripheral blood stem cell (PBSC) harvesting following ifosfamide-vinorelbine proceeded to receive high-dose chemotherapy (HDCT) and PBSC transplantation. The main toxic effect was grade III-IV neutropenia, documented in 65% of cycles with a median duration of 4 days, and non-haematological toxicity was mild. The combination of high-doses of ifosfamide and vinorelbine was well tolerated and an active regimen in treatment of patients with relapsed and refractory HD. It was not only useful as salvage therapy with or without consolidative radiotherapy but it also was a valuable induction regimen before high-dose intensification therapy followed by PBSC reinfusion in patients eligible for this approach.

Large-scale feasibility of gene transduction into human CD34+ cell-derived dendritic cells by adenoviral/polycation complex

With a view to using multiple injections of anti-cancer dendritic cell (DC)-based vaccines, we evaluated the feasibility of the adenoviral transduction of large amounts of human CD34+ cell-derived DCs, and analysed the persistence of the transgene expression and the integrity of DC functional activity after the transduction/cryopreservation procedures. Mature DCs generated from highly enriched human CD34+ cells were transduced by a recombinant adenovirus (rAd-MFG) that carried a modified, membrane-exposed, alkaline phosphatase (AP) sequence as the reporter gene. Cationic lipids such as LipofectAmine or poly-L-lysine were mixed with the viral particles before the transduction of the target cells. The highest transduction efficiency was obtained at a multiplicity of infection (MOI) rate of 500 (AP + DCs: 50 +/- 2%, viability =95%) under both small- and large-scale conditions. The addition of poly-L-lysine or LipofectAmine increased the percentage of transduced cells at an MOI of 500 (CD1a+/AP+ cells = 85 +/- 3% and 80 +/- 2% respectively). Polycations made it possible to reduce the amounts of viral particles, with high efficiency of transduction being achieved at a MOI of 100 with 10 microg/ml poly-L-lysine (CD1a+/AP+: 68 +/- 9%) or 30 microg/ml LipofectAmine (CD1a+/AP+: 60 +/- 7%). Evaluation of the immunophenotype of the transduced DCs showed that the lack of a DC subpopulation was more susceptible to adenoviral transduction. Cryopreservation of transduced DCs did not modify the viability or percentage of AP+ cells that maintain antigen-presenting cell (APC) functions. These findings indicate the efficacy of this method for the transduction of large amounts of CD34+ cell-derived DCs using small quantities of adenoviral vector mixed with polycations. Cryopreservation of transduced DCs did not damage their viability or APC functions, thus making it possible to plan multiple injections of engineered DC-based vaccines.

Nitrate-enhanced gated technetium 99m sestamibi SPECT for evaluating regional wall motion at baseline and during low-dose dobutamine infusion in patients with chronic coronary artery disease and left ventricular dysfunction: comparison with two-dimensional echocardiography

BACKGROUND

The value of gated single photon emission computed tomography (SPECT) in the assessment of wall motion (WM) in patients with severe perfusion defects and in the evaluation of low-dose dobutamine (LDD)-induced changes is not yet established. In patients with chronic coronary artery disease who have left ventricular (LV) dysfunction, the results of nitrate-enhanced technetium 99m sestamibi (sestamibi) gated SPECT for the evaluation of resting and LDD WM were compared with those of baseline and LDD echocardiography (LDDE).

METHODS AND RESULTS

Thirty-seven patients underwent echocardiography and nitrate-enhanced sestamibi gated SPECT within 1 week at rest and during LDD infusion. WM was scored from 1 (normal) to 4 (dyskinetic) by using a 16-segment model. Segments with sestamibi uptake less than 30% were considered unsuitable for WM analysis (36 of 592 segments). Echocardiography was technically unreliable in 10 of 592 segments. The precise agreement between echocardiography and gated SPECT for baseline regional WM was 68.4% (kappa = 0.54), without significant differences for the involved coronary artery territory. The agreement for +/- 1 WM scoring was 96.5% (kappa = 0.94). Contractile reserve during LDD was detected by means of echocardiography in 36% and by means of sestamibi gated SPECT in 33% of baseline asynergic segments. Agreement for detection of WM improvement in response to LDD was 74% (kappa = 0.41). The overall and +/-1 WM score agreement for LDD WM was 67.5% (kappa = 0.50) and 94.7% (kappa = 0.91), respectively. A significant correlation between echocardiography and gated SPECT was observed for both baseline (p = 0.78) and LDD (p = 0.74) WM score index.

CONCLUSIONS

In patients with coronary artery disease who have LV dysfunction, nitrate-enhanced sestamibi gated SPECT allows a reliable WM evaluation, both at rest and during LDD infusion, in almost all segments and provides results in agreement with LDDE.

Successful in vivo purging of CD34-containing peripheral blood harvests in mantle cell and indolent lymphoma: evidence for a role of both chemotherapy and rituximab infusion

Elimination of tumor cells ("purging") from hematopoietic stem cell products is a major goal of bone marrow-supported high-dose cancer chemotherapy. We developed an in vivo purging method capable of providing tumor-free stem cell products from most patients with mantle cell or follicular lymphoma and bone marrow involvement. In a prospective study, 15 patients with CD20(+) mantle cell or follicular lymphoma, bone marrow involvement, and polymerase chain reaction (PCR)-detectable molecular rearrangement received 2 cycles of intensive chemotherapy, each of which was followed by infusion of a growth factor and 2 doses of the anti-CD20 monoclonal antibody rituximab. The role of rituximab was established by comparison with 10 control patients prospectively treated with an identical chemotherapy regimen but no rituximab. The CD34(+) cells harvested from the patients who received both chemotherapy and rituximab were PCR-negative in 93% of cases (versus 40% of controls; P =.007). Aside from providing PCR-negative harvests, the chemoimmunotherapy treatment produced complete clinical and molecular remission in all 14 evaluable patients, including all 6 with mantle cell lymphoma (versus 70% of controls). In vivo purging of hematopoietic progenitor cells can be successfully accomplished in most patients with CD20(+) lymphoma, including mantle cell lymphoma. The results depended on the activity of both chemotherapy and rituximab infusion and provide the proof of principle that in vivo purging is feasible and possibly superior to currently available ex vivo techniques. The high short-term complete-response rate observed suggests the presence of a more-than-additive antilymphoma effect of the chemoimmunotherapy combination used.

Comparison of baseline and low-dose dobutamine technetium-99m sestamibi scintigraphy with low-dose dobutamine echocardiography for predicting functional recovery after revascularization

Injection of sestamibi during low-dose dobutamine (LDD) infusion might improve tracer ability to detect viable myocardium. This study investigated the potential value of LDD technetium-99m sestamibi (sestamibi) single-photon emission computed tomography (SPECT) in predicting functional recovery after revascularization by comparing its results with those of sestamibi SPECT at rest and of LDD echocardiography. Before revascularization, 23 patients with chronic coronary artery disease and regional left ventricular dysfunction underwent sestamibi SPECT at rest and, on a separate day, LDD echocardiography and sestamibi SPECT with tracer injection during LDD infusion. Echocardiography at rest was repeated after revascularization. Semiquantitative sestamibi uptake results (grading from 0 = normal to 4 = absent) and wall motion (grading from 1 = normal to 4 = dyskinesia) were evaluated with a 16-segment model. The ventricular wall was divided into 3 vascular territories. At follow-up, 20 of 32 asynergic vascular territories showed functional recovery, whereas 12 showed no changes. For prediction of functional recovery, LDD SPECT achieved better accuracy than SPECT at rest (87% vs 65%, p <0.05); positive and negative predictive values of LDD SPECT were 90% and 83%, respectively, which was not significantly different from the related LDD echocardiographic values (84% and 69%). Thus, LDD sestamibi SPECT appears to be a promising method for detecting myocardial viability, which provides better accuracy than sestamibi SPECT at rest, and achieves predictive values comparable to those of LDD echocardiography.

Recombinant adenoviral vector-lipofectAMINE complex for gene transduction into human T lymphocytes

We have evaluated, as a vector for gene transfer into human T lymphocytes, a recombinant adenovirus (rAd-MFG-AP) carrying a modified, membrane-exposed, alkaline phosphatase (AP) as reporter gene. CD3+ cells were selected from the buffy coat of healthy donors by the immunomagnetic technique. The positive cell population, comprising 96+/-2% CD3+ cells, was cultured with clinical-grade cytokine(s) for 3-7 days prior to rAd-MFG-AP transduction and the transgene expression was evaluated 48 hr later by indirect immunofluorescence flow cytometry assay with an anti-alkaline phosphatase antibody. The best efficiency of transduction was achieved on incubation of CD3+ cells with IL-2 plus either IL-12 (AP+ cells, 12+/-3%) or IL-7 (AP+ cells, 11+/-3%). To increase further the efficiency of transduction, we have combined LipofectAMINE and rAd-MFG-AP with the aim to enhance the uptake of viral particles into the target cells. The percentage of CD3+ cells transduced by rAd-MFG-AP-LipofectAMINE complex was 24+/-4% (range, 20-35%) after incubation with IL-2 plus IL-7 and 22+/-4% (range, 18-32%) after incubation with II-2 plus IL-12. Forty-eight hours after the incubation with rAd-MFG-AP, the transduced T lymphocytes were subjected to fluorescence-activated cell sorting and fractionated into AP+ and AP- cell subpopulations. The AP+ cell fraction, comprising 96.8% of AP+ cells, was evaluated by FACScan analysis for T lymphocyte surface antigens. The immunophenotyping of the transduced T lymphocytes has shown that there was not a particular subtype of T lymphocytes more susceptible to rAd-MFG-AP transduction. In addition, the transgene expression did not modify T lymphocyte functions, as demonstrated by results obtained by cytotoxicity assay before and after rAd-MFG-AP-LipofectAMINE complex transduction. In conclusion, human T lymphocytes can be efficiently transduced, under clinically applicable conditions, by adenovirus-LipofectAMINE complex after 7 days of culture with IL-2 and IL-12 or IL-7.

Cells with clonal light chains are present in peripheral blood at diagnosis and in apheretic stem cell harvests of primary amyloidosis

In primary systemic amyloidosis, small numbers of bone marrow plasma cells secrete monoclonal light chains that form extracellular fibrils (amyloid) in various organs. Evidence limited to a few cases suggests that rare clonal elements can also be found in the peripheral blood (PB), and this may be relevant in PB stem cell autotransplantation. Since up to 40% of amyloid clones do not synthesize heavy chains, in order to detect tumor cells with high specificity and sensitivity we developed a seminested allele-specific oligonucleotide polymerase chain reaction for tumor light chains. Clone-related sequences were detected in DNA and/or cDNA from the PB cells of eight of 10 patients at diagnosis and from apheretic collections of three of four cases undergoing PB progenitor autotransplantation. Since there are experimental data suggesting that circulating tumor cells may be involved in the growth of the amyloidogenic clone and may be chemoresistant, these findings are relevant to the use of leukapheresis purging strategies for PB progenitor autotransplantation in amyloidosis.

Gene transfer into human dendritic antigen-presenting cells by vaccinia virus and adenovirus vectors

In a search for means to deliver exogenous gene(s) into human dendritic cells (DCs) from the perspective of tumor-specific vaccination, we have evaluated two recombinant viruses, both of which carry a reporter gene which is namely a modified vaccinia virus Ankara (MVA) and an adenovirus, as possible expression vectors. The recombinant MVA-P11 LZ vector carries the Escherichia coli lacZ gene coding for the enzyme beta-galactosidase, and the recombinant Ad-MFG-AP vector carries a modified membrane-exposed alkaline phosphatase (AP) gene. DCs were generated ex vivo in the presence of tumor necrosis factor-alpha, granulocyte macrophage colony-stimulating factor, stem cell factor, and flk-2/flt-3 ligand taken from CD34+ hematopoietic progenitors that were mobilized into the peripheral blood of cancer patients treated with high-dose cyclophosphamide and filgrastim. The target cells used for gene delivery were either CD34+ cells that had been subsequently induced to differentiate into mature DCs or DCs transduced after ex vivo generation from CD34+ cells. The results showed that: (a) infection of CD34+ cell derived-DCs (mature DCs) with either viral vector resulted in the efficient synthesis of recombinant protein, and (b) CD34+ cells were permissive for the expression of the recombinant reporter gene after infection with Ad-MFG-AP but not after infection with MVA-P11 LZ. In conclusion, these results suggest that vaccinia and adenovirus vectors are candidate to act as vehicles in genetically engineering human DCs.

Adenovirus vectors for gene transduction into mobilized blood CD34+ cells

Mobilized blood CD34+ cells from cancer patients were ex vivo infected by a recombinant adenovirus vector carrying an alkaline phosphatase gene, whose expression is evaluable by flow cytometry. A mean of 40% CD34+ cells were infected by the vector, with high levels of expression of the transgene. Among attempts to improve infection efficiency by manipulating culture conditions, only reinfection by the same vector achieved a 10% increase of transgene expression. Transduced CD34+ cells were induced to differentiate along the myeloid and the dendritic lineage, and in either case AP+ cells were detectable among the differentiated cell population. We conclude that adenovirus vectors may be useful tools for gene transduction into mobilized blood CD34+ cells, particularly for those applications in which high transgene expression for limited periods of time is required.

[Controlled clinical study of doxophylline versus aminophylline in the treatment of acute cardiorespiratory insufficiency syndromes]

Twenty patients of both sexes, hospitalized because they were suffering from acute cardiorespiratory syndromes, have been studied in a clinical blind test on unbalanced groups of patients. This research aims to evaluate the therapeutic efficiency and intravenous tolerance of doxophylline. Patients were observed for 24 hours. Signs and symptoms were recorded on a semi-quantitative scale, and the clinical situation, haemogasanalysis, blood pressure, cardiac frequency, and other analytic controls were performed in order to verify the systemic tolerability. We can conclude, in agreement with the literature, that the group treated with doxophylline showed a better reduction in cardiac frequency, while maintaining the same effects on the respiratory apparatus.

Elimination of bcl-2-IgH-positive follicular lymphoma cells from blood transplants with high recovery of hematopoietic progenitors by the miltenyi CD34+ cell sorting system

Contamination of autologous blood cell transplants with cells of follicular non-Hodgkin's lymphoma (F-NHL) may contribute to relapse of the malignancy after potentially curative high doses of chemotherapy and radiotherapy. In an attempt to circumvent this limitation, we have evaluated various techniques of selection of CD34+ cells to eliminate malignant cells from blood cell transplants of five patients with F-NHL undergoing high-dose sequential therapy. The contamination of F-NHL cells was evaluated using a nested PCR assay for the detection of bcl-2-IgH rearrangement with a sensitivity of one F-NHL cell in 10(5) normal cells. In two experiments with blood cell transplant fractions of 0.5 x 10(9) nucleated cells, negative selection of CD34+ cells by removal of B cells and other mature cells that naturally adhere to nylon wool fibers decreased the number of CD19+ B cells detectable by flow cytometry but failed to eliminate bcl-2-IgH-positive F-NHL cells detectable by PCR. In contrast, positive selection of CD34+ cells by the Miltenyi MiniMACS high gradient magnetic cell sorting system in five separate experiments resulted in: (1) the elimination of F-NHL cells in four out of five cases as detected both flow cytometry and bclk-2-IgH PCR; (2) a highly purified population of hematopoietic progenitors comprising 90.8% +/- 2.3% CD34+ cells; and (3) the recovery of 77.9% +/- 3.2% CD34+ cells. These favorable results were confirmed on a large-scale with a blood cell transplant comprising 5.8 x 10(9) nucleated cells in which positive selection of CD34+ cells by the Miltenyi SuperMACS system resulted in: (1) the elimination of F-NHL cells as detected both by flow cytometry and bcl-2-IgH PCR; (2) a highly purified population of hematopoietic progenitors comprising 94.6% CD34+ cells; and (3) the recovery of 62.7% CD34+ cells. These results, attained with the newly available Super MACS system, compare favorable with previous techniques because they show the feasibility of eliminating F-NHL cells from blood cell transplants without relevant nonspecific loss of hematopoietic progenitors.

[Changes in myocardial Tc-99m-sestamibi uptake in asynergic territories during low-dose echo-dobutamine test]

BACKGROUND

Recent data suggest that contractile reserve in dysfunctional but viable myocardium during low-dose dobutamine infusion might be elicited not only by a direct inotropic stimulation but also by an increase in coronary blood flow. Aim of the study was to evaluate the effects of low-dose dobutamine on myocardial perfusion and function in asynergic but viable myocardium.

METHODS

Nineteen patients with coronary artery disease and severe regional dysfunction were studied. Both regional ventricular function and myocardial perfusion were assessed at rest (PRE), during low-dose dobutamine (DOB) and, in twelve patients, after revascularization (POST). Regional ventricular function was evaluated with two-dimensional echocardiography using a score index ranging from 1 to 4. Myocardial perfusion was studied using Tc-99m-sestamibi Single Photon Emission Tomography (SPET); uptake defects were graded from 0 (normal) to 4 (absent uptake). For both evaluations the left ventricle was divided in 16 segments and two vascular territories were considered.

RESULTS

Low-dose dobutamine elicited contractile reserve in 12 of 24 asynergic vascular territories (DOB+). Compared with PRE scintigraphy, DOB SPET showed perfusion improvement in 10/12 DOB+ and in 3/12 DOB- asynergic territories (p = 0.006). Mean uptake score decrease significantly in DOB+ (from PRE SPET 21.0 +/- 7.2 to DOB SPET 17.6 +/- 7.1; p = 0.0005) but not in DOB- (from SPET PRE 19.0 +/- 5.3 to SPET DOB 19.5 +/- 6.8, p = NS) abnormal territories. Fourteen asynergic territories underwent revascularization. Among them, 9 showed functional recovery after intervention (viable myocardium) and 5 showed no changes (fibrotic myocardium). A functional improvement under dobutamine was observed in 7 viable and in 1 fibrotic territories. Conversely, perfusion improved under dobutamine in 8 viable and in one fibrotic territory. After revascularization the perfusion defect score decreased significantly in viable territories (from PRE SPET 22.1 +/- 7.9 to POST SPET 13.3 +/- 6.6; p = 0.00001) but not in fibrotic regions (from PRE SPET 17.8 +/- 6.0 to POST SPET 15.6 +/- 4.9).

CONCLUSIONS

In asynergic myocardium contractile reserve elicited by low-dose dobutamine is associated in most cases with an improvement in Tc-99m-sestamibi uptake. This suggests a possible link between increased blood flow and functional improvement during dobutamine in viable myocardium.

[Long-term hematopoietic reconstitution after myeloablative antitumor therapy and circulating hematopoietic stem cell transplantation]

BACKGROUND

It remains unknown if hematopoiesis reconstituted by autografting with the sole peripheral blood hematopoietic progenitors (CPCs) after myeloablative high dose radiotherapy and/or chemotherapy is durable and capable of coping with increased demand due to boost radiotherapy, surgery, or infection.

PATIENTS AND METHODS

Durability of hematopoiesis was evaluated in 34 consecutive cancer patients treated with myeloablative total body irradiation (n = 17, median follow-up 3 years, range 3-49 months) and/or alkylating agent chemotherapy (n = 17, median follow-up 8 months, range 6-41 months) and autografted with CPCs because bone marrow autografting was contraindicated. CPCs (> or = 8 x 10(8) CD34+ cells/kg) had been collected during mobilization into the circulation in response to previous anticancer therapy and hematopoietic growth factor(s).

RESULTS

Following brief temporary pancytopenia, all patients achieved normal and durable hematopoiesis. The newly reconstituted hematopoietic system was capable of reacting favorably to stressful and noxious events such as surgery, radiotherapy, or varicella-zoster infection. No secondary irreversible failure of blood cell production occurred.

CONCLUSIONS

The documentation of the durability of normal hematopoiesis following myeloablative cancer therapy and autografting with mobilized CPCs implies that the latter procedure, rather than solely an alternative to bone marrow autografting, represents an advantageous tool of choice permitting substantial amelioration of the therapeutic index of high-dose cancer therapy.

Induction of cyclophosphamide-resistance by aldehyde-dehydrogenase gene transfer

The identification of genes inducing resistance to anticancer chemotherapeutic agents and their introduction into hematopoietic cells represents a promising approach to overcome bone marrow toxicity, the limiting factor for most high-dose chemotherapy regimens. Because resistance to cyclophosphamide has been correlated with increased levels of expression of the aldehyde-dehydrogenase (ALDH1) gene in tumor cell lines in vitro, we tested whether ALDH1 overexpression could directly induce cyclophosphamide resistance. We have cloned a full-length human ALDH1 cDNA and used retroviral vectors to transduce it into human (U937) and murine (L1210) hematopoietic cell lines that were then tested for resistance to maphosphamide, an active analogue of cyclophosphamide. Overexpression of the ALDH1 gene resulted in a significant increases in cyclophosphamide resistance in transduced L1210 and U937 cells (50% inhibition concentration [IC50], approximately 13 mumol/L). The resistant phenotype was specifically caused by ALDH1 overexpression as shown by its reversion by disulfiram, a specific ALDH1 inhibitor. ALDH1 transduction into peripheral blood human hematopoietic progenitor cells also led to significant increases (4- to 10-fold; IC50, approximately 3 to 4 mumol/L) in cyclophosphamide resistance in an in vitro colony-forming assay. These findings indicate that ALDH1 overexpression is sufficient to induce cyclophosphamide resistance in vitro and provide a basis for testing the efficacy of ALDH1 gene transduction to protect bone marrow cells from high-dose cyclophosphamide in vivo.

[Cardiac effects of carbamazepine therapy]

The authors describe the case of an epileptic patient in chronic therapy with carbamazepine, and with plasma concentration of the drug in therapeutical range, who suffers from persistent sinus tachycardia. At the present time the observations available in the literature on cardiac toxicity of carbamazepina concern the appearance of sinus tachycardia as consequence of overdose and of blocks of conduction in elderly with carbamazepine in therapeutical range.

[Mitral valve prolapse: the clinical and echocardiographic characteristics in a hospital outpatient population]

BACKGROUND

Mitral valve prolapse (MVP) is generally regarded as a benign condition, but serious complications (including severe mitral insufficiency, cerebral ischemia, infective endocarditis, complex arrhythmias and sudden death) have been described in a minority of patients and have been correlated to demographic, clinical and echocardiographic characteristics. Both a lack of standardized definition of MVP in earlier studies and the different ways of recruitment of MVP patients may explain the variability in reported complication rates.

METHODS

As an offspring of a larger prospective study this paper focuses on the profile of patients who were found to have MVP by M-Mode and two-dimensional echocardiography in several outpatient hospital departments. A total of 8252 consecutive subjects, examined since March 1990 to February 1991 in the Echo laboratories of the Florence area are considered; according to the presence or absence of structural changes (anterior mitral leaflet thickness > 5 mm, leaflet redundancy and/or anulus dilatation) two groups of patients with MVP (A and B) were identified.

RESULTS

A MVP was diagnosed in 288 subjects (3.5%), 170 females (59%) and 118 males (41%), mean age 41 +/- 18 years (range 7-84). 110 (38%) were in Group A, 178 (62%) in Group B. The following parameters differed significantly in the two groups: age (45 +/- 17 vs 39 +/- 17 years; p < 0.003); male gender (50% vs 35%; p < 0.01); auscultatory findings (midsystolic click: 31% vs 68%; p < 0.00001; holosystolic murmur: 22% vs 3%; p < 0.00001); left ventricular diameter (53 +/- 7 vs 48 +/- 5 mm; p < 0.00001) and left atrial diameter (38 +/- 8 vs 33 +/- 5 mm; p < 0.00001). Among patients with mitral regurgitation detected by Color Doppler Echocardiography 65% were in Group A (p < 0.00001).

CONCLUSIONS

These patients with MVP are obviously selected by the modality of recruitment; hence there is a higher prevalence of subjects with morphologic abnormalities and mitral regurgitation who are older and more likely to be male if compared to individuals with MVP who are found in the general population. A long-term follow-up of these patients is ongoing: owing to the data of the literature about prognostic predictors, a higher incidence of complications with a different prognosis between the two groups (with or without structural changes of the mitral valve) is expected.

Large-scale enrichment of mobilized CD34+ peripheral blood hematopoietic progenitors by removal of nylon wool-adherent mature cells

With the aim of facilitating the ex vivo manipulation of peripheral blood hematopoietic progenitors (CPCs = circulating progenitor cells) collected by leukapheresis, we removed polymorphonuclear cells and monocytes that naturally adhere to nylon wool fibers. Leukapheresed cells harvested at the time of hematopoietic recovery after cancer therapy with high-dose cyclophosphamide plus hematopoietic growth factors were incubated with nylon wool fibers for 1 h at 37 degrees C. Evaluation of the cells non-adherent to the nylon wool in all experiments (n = 14) showed that the median recovery of nucleated cells and CPCs detected as CD34+ cells, CFU-GM and BFU-E was 16.4% (range 4.8%-34.0%), 60.0% (range 30.8-80.8%), 60.9% (range 33.4-74.5%) and 65.5% (range 30.8-69.2%), respectively. Therefore exposure to the nylon wool determined a selective removal of mature cells and a complementary enrichment of CPCs. The wide range of results depended on the significantly different cell compositions of the unmanipulated leukaphereses. The latter from patients receiving rhG-CSF (n = 10) comprised a median of 88.5% (range 77.8-93.8%) and 11.5% (range 6.2-22.2%) polymorphonuclear and mononuclear cells, respectively. In contrast, leukaphereses from patients receiving rhGM-CSF or PIXY321 (n = 4) comprised a median of 71.1% (range 55.4-85.0%) and 28.9% (range 15.0-44.6%) polymorphonuclear and mononuclear cells, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantization of CD34+ peripheral blood hematopoietic progenitors for autografting in cancer patients

After myeloablative regimens, combined reinfusion of peripheral blood hematopoietic circulating progenitor cells (CPC) and bone marrow, yields a very rapid hematopoietic recovery. Therefore, based on the knowledge that CPC express the CD34 and CD33 differentiation antigen, we have developed a direct immunofluorescence flow cytometry assay to detect the peak of CPC in the peripheral blood of patients treated with high dose chemotherapy and growth factors. This assay, compared to CFU-GM assay, has the following advantages: 1) easy to do 2) standardized method 3) real time information on CPC number. This work illustrates the practical aspects of this assay and substantiate the widespread use of the CD34/33 flow cytometry assay to guide harvesting of circulating hematopoietic progenitors for autologous transplantation.

High-dose sequential chemo-radiotherapy with peripheral blood progenitor cell support for relapsed or refractory Hodgkin's disease--a 6-year update

BACKGROUND

Very few studies using high-dose therapy and autologous bone marrow transplantation have a long (i.e., > 3 years) follow-up. We report here the 6-year update of a study employing high-dose sequential chemo-radiotherapy in 25 patients with poor-risk Hodgkin's disease.

PATIENTS AND METHODS

All patients were either refractory (7 patients) or partial responders (9 patients) or early relapses (9 patients) following induction chemotherapy consisting of MOPP/ABVD in 20 patients and MOPP/ABVD followed by salvage CEP for the remaining 5 patients. The high-dose chemo-radiotherapy regimen employed consisted in the rapid sequential administration of high-doses of cyclophosphamide, methotrexate, etoposide and total body irradiation plus melphalan.

RESULTS

As compared to 4-year results, the 6-year probabilities of relapse-free survival, freedom from progression and overall survival were almost superimposable. In fact, during the two additional years elapsed since prior survey, only one event occurred (fatal cerebral hemorrhage) that was unrelated to Hodgkin's disease. In particular, the proportion of patients remaining event-free was 78% for those with short initial complete response and 31% for patients who had failed initial MOPP/ABVD. According to previous experience, both groups have a very low or no chance of long-term event-free survival when treated with standard-dose salvage chemotherapy.

CONCLUSIONS

The very favorable long-term results of the high-dose sequential regimen together with its excellent tolerability and lack of early or late fatal toxicities, will assist clinicians in defining optimal timing for high-dose therapy in the management of Hodgkin's disease. According to a revised cost/benefit analysis, it would appear that, at present, the best timing of high-dose sequential therapy in patients failing MOPP/ABVD is at first early relapse.

Recombinant human interleukin-3 hastens trilineage hematopoietic recovery following high-dose (7 g/m2) cyclophosphamide cancer therapy

BACKGROUND

Interleukin-3, a recombinant cytokine with multilineage stimulatory effect on hematopoietic cells, was administered to 22 previously untreated breast cancer patients following high-dose therapy with cyclophosphamide (7 g/m2).

PATIENTS AND METHODS

The growth factor, administered through continuous intravenous infusion at 1 (3 patients), 2.5 (3 patients), 5 (10 patients) and 10 micrograms/kg/day (6 patients), was well tolerated up to 5 micrograms/kg/day.

RESULTS

Nausea, vomiting, fever and headache prevented administration of the intended dose to all 6 patients in the 10 micrograms/kg/day cohort. At the maximal tolerable dose (5 micrograms/kg/day) the growth factor significantly accelerated granulocyte, platelet and reticulocyte recovery as compared to matched historical controls who received high-dose cyclophosphamide without cytokine infusion. Moreover, no platelet transfusions and fewer erythrocyte transfusions were required in interleukin 3-treated patients. In contrast to GM-CSF and G-CSF, interleukin 3 showed no effect on the mobilization of hematopoietic progenitor cells in the peripheral blood.

CONCLUSIONS

Interleukin-3 represents a well-tolerated cytokine, clinically useful for accelerating trilineage hematopoietic recovery following severely myelotoxic treatments such as high-dose cyclophosphamide.

Clinical implications of the heterogeneity of hematopoietic progenitors elicited in peripheral blood by anticancer therapy with cyclophosphamide and cytokine(s)

Clinical investigators have found that the hematopoietic system irreversibly damaged by cancer therapy with myeloablative high doses of chemoradiotherapy can be reconstituted by transplantation of autologous hematopoietic progenitors retrieved from peripheral blood. In comparison with patients transplanted with bone marrow, those who receive peripheral blood progenitors undergo shorter periods of neutropenia and thrombocytopenia, require less platelet and erythrocyte transfusions and, most importantly, experience overall reduced treatment-related morbidity. In this article, we speculate that an explantation for this clinical achievement may be that committed hematopoietic progenitors as well as ancestral uncommitted pluripotent stem cells are retrieved from circulation and transplanted after myeloablative cancer therapy. As indicated by studies in rodents, transplantation of hematopoietic progenitors is followed by two phases of engraftment associated with progenitors at different stages of maturation. An initial phase corresponding to early hematopoietic recovery is produced by committed progenitors, and a second sustained engraftment phase is produced by the pluripotent stem cell. Should this multiphase engraftment model be true of humans also, the exceptionally prompt and sustained blood cell count recovery achieved by transplanting blood progenitor cells may reflect transplantation of heterogeneous progenitors such as committed progenitors and pluripotent stem cells producing an early engraftment phase and then sustained hematopoiesis, respectively.

Granulocyte-macrophage colony-stimulating factor or granulocyte colony-stimulating factor infusion makes high-dose etoposide a safe outpatient regimen that is effective in lymphoma and myeloma patients

PURPOSE

This study assessed the efficacy of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) or recombinant human granulocyte colony-stimulating factor (rhG-CSF) in ameliorating the extent and duration of hematologic toxicity after high-dose etoposide cancer therapy.

PATIENTS AND METHODS

Thirty-two non-Hodgkin's lymphoma and myeloma patients were treated with 2 to 2.4 g/m2 etoposide infused intravenously (IV) during a 10- to 12-hour period, followed 72 hours later by subcutaneous administration of rhGM-CSF or rhG-CSF. Hematologic toxicity was compared with that observed in 29 patients who were treated with high-dose etoposide without growth factors.

RESULTS

The median duration of grade 4 neutropenia in growth factor-treated patients was 3 days, and granulocyte counts never decreased to less than 100/microL in approximately half of the patients. The corresponding figures in the control patients were 8 and 3 days, respectively (P < .0001). No effect was observed in platelet and RBC recovery. Growth factor-treated patients became eligible to receive additional myelotoxic chemotherapy a median of 5 days earlier than controls. Nonhematologic toxicity was minimal. Grade 1 mucositis was observed in two of 61 patients (3%). Antitumor activity assessed within 1 month after etoposide administration was documented in 58% of 38 assessable patients. Finally, high-dose etoposide expanded and mobilized the pool of peripheral-blood hematopoietic progenitors.

CONCLUSION

The use of rhGM-CSF or rhG-CSF makes high-dose etoposide a safe outpatient regimen and should encourage the inclusion of this highly effective and well-tolerated drug in novel treatment strategies that use high-dose therapy early in the clinical course of chemosensitive tumors.

Human peripheral blood hematopoietic progenitors are optimal targets of retroviral-mediated gene transfer

Hematopoietic progenitor cells circulate in the peripheral blood (PB) of cancer patients during the recovery phase that follows treatment with high-dose cyclophosphamide followed by hematopoietic growth factor infusion. We report that when PB progenitors were exposed in vitro to filtered supernatant from cell line PA317-N2, producing amphotropic helper-free N2 vector at conventional titers, successful retroviral-mediated transfer of neomycin resistance gene was documented by polymerase chain reaction in 93% of day 14 myelomonocytic colonies. Under the same conditions, gene transfer was achieved in 22% of steady-state bone marrow-derived myelomonocytic colonies. Neo-resistance gene transfer was documented also in a CD34+/cyclophosphamide-resistant precursor to granulocyte-macrophage colonies, an undifferentiated progenitor close to the hematopoietic stem cell. Neither cocultivation with vector-producing cells nor high vector titer were stringent requisites for efficient gene transfer. The large-scale availability of PB hematopoietic progenitors in cancer patients, together with the high gene transfer rate achieved under safe and clinically feasible conditions, support an optimal approach for gene transfer procedures into the human hematopoietic system.

Intracellular calcium regulates the tyrosine kinase receptor encoded by the MET oncogene

Previous work (Gandino, L., Di Renzo, M. F., Giordano, S., Bussolino, F., and Comoglio, P.M. (1990) Oncogene 5, 721-725) has shown that the tyrosine kinase activity of the receptor encoded by the MET protooncogene is negatively modulated by protein kinase C (PKC). We now show that an increase of intracellular Ca2+ has a similar inhibitory effect in vivo, via a PKC-independent mechanism. In GTL-16 cells the p145MET kinase is overexpressed and constitutively phosphorylated on tyrosine. A rapid and reversible decrease of p145MET tyrosine phosphorylation was induced by treatment with the calcium ionophores A23187 or ionomycin. Experiments performed with the ionophores in absence of extracellular calcium showed that a rise in cytoplasmic Ca2+ concentration to 450 nM (due to release from intracellular stores) resulted in a similar effect. These Ca2+ concentrations had no effect on p145MET autophosphorylation in an in vitro kinase assay. This suggests that the effect of Ca2+ on p145MET tyrosine phosphorylation is not direct but may be mediated by Ca(2+)-activated proteins(s). Involvement of Ca(2+)-dependent tyrosine phosphatases was ruled out by experiments carried out in presence of Na2VO4. In vivo labeling with [32P]orthophosphate showed that the rise of intracellular Ca2+ induces serine phosphorylation of p145MET on a specific phosphopeptide. This suggests that Ca2+ negatively modulates p145MET kinase through the phosphorylation of a critical serine residue by a Ca(2+)-activated serine kinase distinct from PKC.

Transmembrane signalling at the epidermal growth factor receptor. Positive regulation by the C-terminal phosphotyrosine residues

Mutant epidermal growth factor (EGF) receptors (obtained by substitution of one, two or three C-terminal autophosphorylable tyrosine residues with phenylalanine residues or by deletion of the C-terminal 19 amino acids, including the distal tyrosine) were expressed in mouse NIH-3T3 fibroblast clones at densities comparable (less than 25% difference) with those in control clones expressing the wild-type receptor. Total EGF-induced phosphorylation of the mutated receptors was not appreciably changed with respect to controls, whereas autophosphorylation at tyrosine residues was decreased, especially in the double and the triple mutants. In the latter mutant, expression of the EGF-receptor-activated lipolytic enzyme phospholipase C gamma was unchanged, whereas its tyrosine phosphorylation induced by the growth factor was lowered to approx. 25% of that in the controls. In all of the cell clones employed, the accumulation of inositol phosphates induced by treatment with fetal calf serum varied only slightly, whereas the same effect induced by EGF was consistently lowered in those lines expressing mutated receptors. This decrease was moderate for those receptors missing only the distal tyrosine (point and deletion mutants), intermediate in the dual mutants and almost complete in the triple mutants. Likewise, increases in intracellular Ca2+ concentrations [( Ca2+]i) induced by fibroblast growth factor were approximately the same in all of the clones, whereas those induced by EGF were decreased in the mutants, again in proportion to the loss of the phosphorylable C-terminal tyrosine residues. The same trend occurred with membrane hyperpolarization, an effect secondary to the increase in [Ca2+]i via the activation of Ca2(+)-dependent K+ channels. We conclude that C-terminal autophosphorylable tyrosine residues play a positive role in the regulation of transmembrane signalling at the EGF receptor. The stepwise decrease in signal generation observed in single, double and triple point mutants suggest that the role of phosphotyrosine residues is not in the participation in specific amino acid sequences, but rather in the introduction of strong negative charges at strategic sites of the receptor tail. As a consequence of autophosphorylation, the receptor could become competent for specific association with phospholipase C gamma, with ensuing activation by tyrosine phosphorylation followed by the chains of intracellular responses ultimately leading to DNA synthesis and cell duplication.

Ionic events induced by epidermal growth factor. Evidence that hyperpolarization and stimulated cation influx play a role in the stimulation of cell growth

Charybdotoxin, a blocker of K+ channels, and the imidazole drug SC38249, a blocker of both voltage- and second messenger-operated Ca2+ channels, were employed in mouse NIH-3T3 fibroblasts overexpressing the epidermal growth factor (EGF) receptor 1) to characterize the ionic events activated by EGF; and 2) to establish the role of those events in cell growth. The [Ca2+]i response by EGF was little changed by charybdotoxin while the parallel hyperpolarization was inhibited in a dose-dependent manner. At high toxin concentrations (greater than 3 x 10(-8) M), the effect of EGF on membrane potential was turned into a persistent depolarization sustained by both Na+ and Ca2+. Pretreatment with 10 microM SC38249 induced only minor changes of the intracellular Ca2+ release by EGF (the process responsible for the initial phase of the [Ca2+]i and membrane potential responses) and blocked the persistent, second phase [Ca2+]i and the hyperpolarization responses, both dependent on Ca2+ influx, as well as the depolarization in the charybdotoxin-pretreated cells. Long term (up to 2-day) treatment with either charybdotoxin or SC38249 failed to affect the viability and growth of unstimulated EGFR-T17 cells. Moreover, in these cells, the ionic responses to EGF were restored after a 30-min incubation in fresh medium. In contrast, growth stimulated by EGF was inhibited, moderately (-20%) by charybdotoxin and markedly (-60%) by SC38249. These results indicate for the first time that both hyperpolarization and, especially, the persistent increase of [Ca2+]i sustained by Ca2+ influx play a role in the activity of EGF, ultimately cooperating with other intracellular events in mitogenesis.

Differential coupling of dopaminergic D2 receptors expressed in different cell types. Stimulation of phosphatidylinositol 4,5-bisphosphate hydrolysis in LtK- fibroblasts, hyperpolarization, and cytosolic-free Ca2+ concentration decrease in GH4C1 cells

Dopaminergic D2 receptors are widely regarded as typical inhibitory receptors, as they both inhibit adenylyl cyclase and decrease the cytosolic free Ca2+ concentration ([Ca2+]i) by activating K+ channels. A D2 receptor has recently been cloned (Bunzow, J. R., Van Tol, H. H. M., Grandy, D. K., Albert, P., Salon, J., Christie, M. D., Machida, C. A., Neve, K. A., and Civelli, O. (1988) Nature 336, 783-787) and expressed in two different cell lines, pituitary GH4C1 cells and Ltk- fibroblasts, where it has been shown to induce inhibition of adenylyl cyclase. We have investigated the additional effector systems coupled to this receptor. The responses observed in the two cells lines, which express similar levels of receptors (0.5-1 x 10(5)/cell), were surprisingly different. In GH4C1 cells D2 receptors failed to affect phosphoinositide hydrolysis and induced a decrease of [Ca2+]i. This latter effect appears to be mediated by hyperpolarization, most likely due to the activation of K+ channels. In striking contrast, in Ltk- fibroblasts the D2 receptor induced a rapid stimulation of inositol(1,4,5)-trisphosphate (+73% at 15 s) followed by the other inositol phosphates, and an immediate increase of [Ca2+]i due to both Ca2+ mobilization from internal stores and influx from the extracellular medium. In both GH4C1 and Ltk- cells, the D2 receptor response was mediated by G protein(s) sensitive to pertussis toxin. The increases of inositol trisphosphate and [Ca2+]i observed in Ltk- cells required dopamine concentrations only slightly higher than those inhibiting adenylyl cyclase (EG50 = 25, 29, and 11 nM, respectively) and were comparable in magnitude to the responses induced by the endogenous stimulatory receptor agonists, thrombin and ATP. The results demonstrate that in certain cells D2 receptors are efficiently coupled to the stimulation of phosphoinositide hydrolysis. The nature of receptor responses appears therefore to depend on the specific properties not only of the receptor molecule but also of the cell type in which it is expressed.