Therapeutic efficacy of proton transport inhibitors alone or in combination with cisplatin in triple negative and hormone sensitive breast cancer models

Triple negative breast cancers (TNBCs) are very aggressive and have a poor prognosis due to lack of efficacious therapies. The only effective treatment is chemotherapy that however is frequently hindered by the occurrence of drug resistance. We approached this problem in vitro and in vivo on a triple negative and a hormone sensitive breast cancer cell lines: 4T1 and TS/A. A main defense mechanism of tumors is the extrusion of intracellular protons derived from the metabolic shift to glycolysis, and necessary to maintain an intracellular pH compatible with life. The resulting acidic extracellular milieu bursts the malignant behavior of tumors and impairs chemotherapy. Therefore, we investigated the efficacy of combined therapies that associate cisplatin (Cis) with proton exchanger inhibitors, such as esomeprazole (ESO) and 5-(N-ethyl-N-isopropyl)amiloride (EIPA). Our results demonstrate that in the 4T1 triple negative model the combined therapy Cis plus EIPA is significantly more effective than the other treatments. Instead, in the TS/A tumor the best therapeutic result is obtained with ESO alone. Remarkably, in both 4T1 and TS/A tumors these treatments correlate with increase of CD8+  T lymphocytes and dendritic cells, and a dramatic reduction of M2 macrophages and other suppressor myeloid cells (MDSC) in the tumor infiltrates.

Mechanisms underlying the predictive power of high skeletal muscle uptake of FDG in amyotrophic lateral sclerosis

Background

We recently reported that enhanced [18F]-fluorodeoxyglucose (FDG) uptake in skeletal muscles predicts disease aggressiveness in patients with amyotrophic lateral sclerosis (ALS). The present experimental study aimed to assess whether this predictive potential reflects the link between FDG uptake and redox stress that has been previously reported in different tissues and disease models.

Methods

The study included 15 SOD1^G93A mice (as experimental ALS model) and 15 wildtype mice (around 120 days old). Mice were submitted to micro-PET imaging. Enzymatic pathways and response to oxidative stress were evaluated in harvested quadriceps and hearts by biochemical, immunohistochemical, and immunofluorescence analysis. Colocalization between the endoplasmic reticulum (ER) and the fluorescent FDG analog 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxyglucose (2-NBDG) was performed in fresh skeletal muscle sections. Finally, mitochondrial ultrastructure and bioenergetics were evaluated in harvested quadriceps and hearts.

Results

FDG retention was significantly higher in hindlimb skeletal muscles of symptomatic SOD1^G93A mice with respect to control ones. This difference was not explained by any acceleration in glucose degradation through glycolysis or cytosolic pentose phosphate pathway (PPP). Similarly, it was independent of inflammatory infiltration. Rather, the high FDG retention in SOD1^G93A skeletal muscle was associated with an accelerated generation of reactive oxygen species. This redox stress selectively involved the ER and the local PPP triggered by hexose-6P-dehydrogenase. ER involvement was confirmed by the colocalization of the 2-NBDG with a vital ER tracker. The oxidative damage in transgenic skeletal muscle was associated with a severe impairment in the crosstalk between ER and mitochondria combined with alterations in mitochondrial ultrastructure and fusion/fission balance. The expected respiratory damage was confirmed by a deceleration in ATP synthesis and oxygen consumption rate. These same abnormalities were represented to a markedly lower degree in the myocardium, as a sample of non-voluntary striated muscle.

Conclusion

Skeletal muscle of SOD1^G93A mice reproduces the increased FDG uptake observed in ALS patients. This finding reflects the selective activation of the ER-PPP in response to significant redox stress associated with alterations of mitochondrial ultrastructure, networking, and connection with the ER itself. This scenario is less severe in cardiomyocytes suggesting a relevant role for either communication with synaptic plaque or contraction dynamics.

The Elusive Link Between Cancer FDG Uptake and Glycolytic Flux Explains the Preserved Diagnostic Accuracy of PET/CT in Diabetes

This study aims to verify in experimental models of hyperglycemia induced by streptozotocin (STZ-DM) to what degree the high competition between unlabeled glucose and metformin (MET) treatment might affect the accuracy of cancer FDG imaging. The study included 36 “control” and 36 “STZ-DM” Balb/c mice, undergoing intraperitoneal injection of saline or streptozotocin, respectively. Two-weeks later, mice were subcutaneously implanted with breast (4 T1) or colon (CT26) cancer cells and subdivided in three subgroups for treatment with water or with MET at 10 or 750 mg/Kg/day. Two weeks after, mice were submitted to micro-PET imaging. Enzymatic pathways and response to oxidative stress were evaluated in harvested tumors. Finally, competition by glucose, 2-deoxyglucose (2DG) and the fluorescent analog 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxyglucose (2-NBDG) on FDG uptake was studied in 4 T1 and CT26 cultured cells. STZ-DM slightly decreased cancer volume and FDG uptake rate (MRF). More importantly, it also abolished MET capability to decelerate lesion growth and MRF. This metabolic reprogramming closely agreed with the activity of hexose-6-phosphate dehydrogenase within the endoplasmic reticulum. Finally, co-incubation with 2DG virtually abolished FDG and 2-NBDG uptake within the endoplasmic reticulum in cultured cells. These data challenge the current dogma linking FDG uptake to glycolytic flux and introduce a new model to explain the relation between glucose analogue uptake and hexoses reticular metabolism. This selective fate of FDG contributes to the preserved sensitivity of PET imaging in oncology even in chronic moderate hyperglycemic conditions.

Evaluation of Glycosylated PTGS2 in Colorectal Cancer for NSAIDS-Based Adjuvant Therapy

Observational/retrospective studies indicate that prostaglandin-endoperoxide synthase-2 (PTGS2) inhibitors could positively affect colorectal cancer (CRC) patients' survival after diagnosis. To obtain an acceptable cost/benefit balance, the inclusion of PTGS2 inhibitors in the adjuvant setting needs a selective criterion. We quantified the 72 kDa, CRC-associated, glycosylated form of PTGS2 in 100 frozen CRC specimens and evaluated PTGS2 localization by IHC in the same tumors, scoring tumor epithelial-derived and stroma-derived fractions. We also investigated the involvement of interleukin-1 beta (IL1β) in PTGS2 induction, both in vitro and in CRC lysates. Finally, we used overall survival (OS) as a criterion for patient selection. Glycosylated PTGS2 can be quantified with high sensibility in tissue lysates, but the expression in both tumor and stromal cells limits its use for predictive purposes. Immunohistochemistry (IHC) analysis indicates that stromal PTGS2 expression could exert a protective role on patient OS. Stromal PTGS2 was prevalently expressed by cancer-associated fibroblasts exerting a barrier function near the gut lumen, and it apparently favored the antitumor M1 macrophage population. IL1β was directly linked to gPTGS2 expression both in vitro and in tumors, but its activity was apparently prevalent on the stromal cell population. We suggest that stromal PTGS2 could exert a positive effect on patients OS when expressed in the luminal area of the tumor.

High Chemotactic Motility and Growth in Hard Agar of a Variant of RSV-Transformed Fibroblasts are Lost in Late Passages

Cloning efficiency in hard agar (0.6%) and high chemotactic migration toward fibroblast conditioned medium have been shown to characterize metastatic tumor cells. We studied growth in 0.6% agar and chemotaxis of two lines of Rous Sarcoma virus-transformed Balb/ c3T3 cells, B77/3T3 (low metastatic) and AA12 (high metastatic), and compared them to their non-transformed counterpart, in order to verify whether these properties were maintained during several subcultivations. Cells were cryopreserved at early passages and thawed for experiments. Both assays were performed on freshly thawed cells (4-6 weeks in culture) and on cells which had been cultured 15-20 weeks after thawing. B77/3T3, which are tumorigenic but low metastatic and which have a very low cloning efficiency in hard agar (0.1-1%), showed a chemotactic response to Balb/c3T3 conditioned medium about two-fold higher than control Balb/c3T3. This response did not change with time in culture. AA12 cells, a genetic unstable variant of B77/3T3 selected for its growth in hard agar (0.6%), had a high cloning efficiency in hard agar and showed a high chemotactic motility (three-fold the controls). High growth in 0.6 % agar and high chemotaxis of AA12 were lost in late passages, where cells behaved as the controls. It seems that besides the already reported variation in anchorage-independent growth, genetically unstable tumor cells can also have important variations in chemotactic motility during subcultivations.

Impact of CXCL1 overexpression on growth and invasion of prostate cancer cell

BACKGROUND

The role of CXCL1 in prostate cancer (PCa) progression has been poorly investigated. A limitation of previous studies is linked to the use of human PCa cell lines PC3 and DU145, producing CXCL8 at levels strongly exceeding CXCL1 levels. Moreover, in mouse models the sharing of CXCR2 receptor by both ligands makes the phenotype induced by CXCL8 and CXCL1 almost indistinguishable. To overcome this problem we used the murine TRAMP-C2 cell line, not expressing CXCL8 and expressing CXCL1 at low levels.

METHODS

The effect of CXCL1 overexpression was examined by in vivo subcutaneous tumor studies and in vitro functional assays of invasion and adhesion. Biochemical modifications were evaluated by Western blotting and antibody arrays.

RESULTS

Our data show that the overexpression of CXCL1 in TRAMP-C2 cells represses tumor establishment and in situ invasion. In vitro, the main action of CXCL1 expression in TRAMP cells is associated with the perturbation of molecules linked to cell adhesion and migration thus explaining in vivo data. Other in vitro findings also suggest that signaling by CXCL1 might activate a secretory network limiting in vivo tumor growth by reinforcing senescence. Immunohistochemical staining of human PCa, BPH, and normal prostate biopsies strengthen our observations on the mouse model: when expressed, CXCL1 is limited to small areas with faint staining and PCa progression does not rely on CXCL1 expression.

CONCLUSION

We could speculate that CXCL1 overexpression acts as a suppressor of malignancy limiting the escape of tumor cells from the primary tumor and reinforcing growth arrest.

Amniotic liquid derived stem cells as reservoir of secreted angiogenic factors capable of stimulating neo-arteriogenesis in an ischemic model

Most urgent health problems are related to a blood vessel formation failure. The use of stem cells from different sources or species for both in vitro and in vivo engineering of endothelium does not necessarily imply their direct commitment towards a vascular phenotype. In the present study, we used human amniotic fluid stem cells (AFSC) to evoke a strong angiogenic response in murine recipients, in terms of host guided-regeneration of new vessels, and we demonstrated that the AFSC secretome is responsible for the vascularising properties of these cells. We indentified in AFSC conditioned media (ACM) pro-angiogenic soluble factors, such as MCP-1, IL-8, SDF-1, VEGF. Our in vitro results suggest that ACM are cytoprotective, pro-differentiative and chemoattractive for endothelial cells. We also tested ACM on a pre-clinical model of hind-limb ischemic mouse, concluding that ACM contain mediators that promote the neo-arteriogenesis, as remodelling of pre-existing collateral arteries to conductance vessels, thus preventing the capillary loss and the tissue necrosis of distal muscles. In line with the current regenerative medicine trend, in the present study we assert the concept that stem cell-secreted mediators can guide the tissue repair by stimulating or recruiting host reparative cells.

Unsaturated fatty acids promote hepatoma proliferation and progression through downregulation of the tumor suppressor PTEN

BACKGROUND/AIMS

The impact of dietary fatty acids on the development of cancers is highly controversial. We recently demonstrated that unsaturated fatty acids trigger the downregulation of the tumor suppressor PTEN through an mTOR/NF-kappaB-dependent mechanism in hepatocytes. In this study, we investigated whether unsaturated fatty acids promote hepatoma progression by downregulating PTEN expression.

METHODS

The effects of fatty acids and PTEN-specific siRNAs on proliferation, invasiveness and gene expression were assessed using HepG2 hepatoma cells. The tumor promoting activity of unsaturated fatty acids was evaluated in vivo using HepG2 xenografts in nude mice.

RESULTS

Incubation of HepG2 cells with unsaturated fatty acids, or PTEN-specific siRNAs, increased cell proliferation, cell migration and invasiveness, and altered the expression of genes involved in inflammation, epithelial-to-mesenchymal transition and carcinogenesis. These effects were dependent on PTEN expression levels and were prevented by mTOR and NF-kappaB inhibitors. Consistent with these data, the development and size of subcutaneous HepG2-derived tumors in nude mice xenografts were dramatically increased when mice were fed with an oleic acid-enriched diet, even in the absence of weight gain.

CONCLUSIONS

These data demonstrate that dietary unsaturated fatty acids promote hepatoma progression by reducing the expression of the tumor suppressor PTEN.

Pulmonary masses in a patient with blue-gray cutaneous hyperpigmentation

Authors describe a case of pulmonary masses and estensive skin pigmentation: "blue-gray syndrome" occurred in a patient in amiodarone therapy who presented with progressive dyspnea, cough, and fever. The diagnosis was suspected by detection of a high attenuation of the pulmonary masses on the nonenhanced chest computed tomography (CT) and lots of foamy macrophages in the bronchoalveolar lavage fluid. Relief of respiratory symptoms and radiological improvement was achieved when amiodarone treatment was stopped.

Marine sponge-derived polymeric alkylpyridinium salts as a novel tumor chemotherapeutic targeting the cholinergic system in lung tumors

Previous studies have shown that the cholinergic system plays a pivotal rule in small cell lung cancer (SCLC) cell growth through an autocrine loop that activates the nicotinic cholinergic receptor, which together with the activation of this receptor by nicotine links SCLC evolution with tobacco use. Non-small cell lung cancer (NSCLC) is the most common form of lung cancer and is also linked to tobacco use. Here we describe the presence of molecules of the cholinergic system in NSCLC samples and cell lines and investigate the implications of the cholinergic system in cell growth regulation. Cholino-acetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT) and acetylcholinesterase (AChE) were observed in NSCLC tumor biopsies and in NSCLC cell lines. Polymeric alkylpyridinium salts (poly-APS) are AChE inhibitors isolated from the crude extract of the marine sponge, Reniera sarai. These metabolites were characterized as a mixture of two polymers of 3-octylpyridinium, including 29 and 99 monomeric units. Exposure of normal lung fibroblast and NSCLC cell lines to poly-APS revealed a selective cytotoxicity for cancer cells as compared to the normal fibroblast cell lines. FACS analysis indicated poly-APS induced apoptosis in NSCLC cells but not in normal lymphocytes. Non-toxic doses of poly-APS also potently reduced NSCLC cell-cell adhesion in suspension cultures. The limited toxicity of poly-APS on normal cells was confirmed by injection in the caudal vein of mice. No overt effects on health parameters, such as weight gain and physical behavior, were observed, and histological analysis of major organs did not reveal differences between the treated animals as compared to controls. These data demonstrate that NSCLC cells express cholinergic molecules that may be involved in cell growth regulation and that the cholinesterase inhibitor, poly-APS, shows selective toxicity toward NSCLC cells while having no apparent toxicity towards normal cells and tissue in vitro and in vivo.

Kaposi's sarcoma and human chorionic gonadotropin: mechanisms, moieties and mysteries

Kaposi's Sarcoma (KS) is a highly angiogenic neoplasm associated with infection by the human gamma-herpesvirus, HHV-8 or Kaposi's sarcoma herpes virus (KSHV). When in 1872 the Hungarian scientist Moritz Kaposi described the sarcoma, which was later named after him, he was dealing with a rare dermatologic disease. Today, KS is a more common pathology due to its high incidence in AIDS, in immuno-suppressed transplantation patients and, in its endemic form, in Africa. The introduction of highly active antiretroviral therapy (HAART) has led to a drastic reduction of KS incidence in HIV-infected patients, but in some cases KS resists the treatment. KS is more common in men than in women. The observation of spontaneous remissions during pregnancy stimulated investigations into the potential anti-KS activity of the pregnancy hormone human chorionic gonadotropin (hCG). The variable effect in clinical trials using urinary preparations of the hormone (u-hCG) has led to the hypothesis that contaminating moieties present in these preparations may account for the anti-KS effect observed in vitro. While the discrepancy between laboratory tests and clinical trials remains a mystery, little is known about potential anti-KS mechanisms of the hormone itself and/or other active moieties present in u-hCG.

HIV type 1 Tat protein is a survival factor for Kaposi's sarcoma and endothelial cells

The HIV-1 Tat protein has been directly implicated in the pathogenesis of AIDS-related Kaposi's sarcoma (KS); however, its effects on KS spindle-shaped and endothelial cell apoptosis are largely unexplored. Since susceptibility to apoptosis is relevant for tumor development and response to therapy, we investigated the effects of Tat on KS and endothelial cell survival from apoptosis. The effect of Tat was evaluated in three KS cell lines (KS-imm, KS-C1, and KS-L3) exposed to the chemotherapy agent vincristine, currently used for the treatment of this tumor, and in human umbilical vein-derived endothelial cells (HUVECs) induced to undergo apoptosis by serum withdrawal. Apoptosis was assessed by enzymatic assays, microscopic examination of chromatin and cytoskeleton, evaluation of plasma membrane integrity and subdiploid DNA content, TUNEL assays, and measurement of caspase-3 activity. Tat, in a dose-dependent manner, protected the three KS cell lines and HUVECs from apoptosis induced by vincristine or serum starvation, respectively. This effect appeared to be independent of modulation of Fas, Bcl-2, or Bax expression. In contrast, Tat upregulated Bcl-X(L) expression and induced a relevant decrease in caspase-3 activity in vincristine-treated KS cells. Taken together, these results suggest that the HIV-1 Tat protein may factor KS development and progression by sustaining endothelial and transformed cell survival.

N-Acetylcysteine counteracts erythrocyte alterations occurring in chronic obstructive pulmonary disease

A key role has been proposed for reactive oxygen species (ROS) in chronic obstructive pulmonary disease (COPD). Aim of the present work was to evaluate possible implications of ROS in the integrity and function of the cell type mainly involved in oxygen uptake and delivery to the peripheral tissues: the erythrocyte. Red blood cells (RBCs) were thus collected from blood samples from COPD patients. Furthermore, blood samples from the same patients treated with the antioxidizing drug of widespread use in such disease i.e., N-acetylcysteine (NAC), were also considered. Morphometric and analytical cytology studies were then conducted. We report herein that: (i) alterations of RBC ultrastructure were detectable in RBCs from COPD patients, that (ii) relevant changes of spectrin cytoskeleton and glycophorin expression were also found and that (iii) NAC treatment was capable of significantly counteracting these changes. These results are consistent with a reappraisal of the role of RBCs in this disease.

Kaposi's sarcoma cells of different etiologic origins respond to HIV-Tat through the Flk-1/KDR (VEGFR-2): relevance in AIDS-KS pathology

Kaposi's sarcoma (KS) is an hyperplastic lesion whose main histological features are typical spindle shaped cells with a mixed endothelial-mesenchymal-macrophage phenotype, an intense vascularization and an inflammatory infiltrate. The etiology of KS appears to be linked to activation of a latent HHV8 infection. Sporadic and iatrogenic KS are slow progressing lesions that can undergo spontaneous regression. In contrast, KS, which is frequently associated with HIV infection, is found in a highly aggressive form in AIDS patients. The HIV-1 Tat has been shown to activate the VEGF receptor KDR in endothelial and KS spindle cells, suggesting this HIV protein could contribute to KS pathogenesis. We used primary 'reactive' KS cell culture from sporadic and epidemic KS, and an immortal KS-line (KS-Imm) isolated in our laboratory from a iatrogenic KS lesion, to verify if Tat-induced cell signaling is able to mediate cellular responses. We demonstrate that KS cells migrated in response to Tat and that VEGF is able to compete with the Tat chemotactic activity towards these cells. A function-blocking anti-KDR antibody was able to abrogate both VEGF and Tat-induced KS chemotactic response, indicating a direct involvement of this receptor. Our data show that HIV-Tat can also activate KS cells derived from sporadic or iatrogenic lesions, suggesting that in AIDS patients Tat could cooperate with VEGF in activation of KDS on KS precursor spindle and endothelial cells, and contribute to the aggressiveness of AIDS-KS lesions.

Ventilatory and metabolic adaptations to walking and cycling in patients with COPD

To test the hypothesis that in chronic obstructive pulmonary disease (COPD) patients the ventilatory and metabolic requirements during cycling and walking exercise are different, paralleling the level of breathlessness, we studied nine patients with moderate to severe, stable COPD. Each subject underwent two exercise protocols: a 1-min incremental cycle ergometer exercise (C) and a "shuttle" walking test (W). Oxygen uptake (VO(2)), CO(2) output (VCO(2)), minute ventilation (VE), and heart rate (HR) were measured with a portable telemetric system. Venous blood lactates were monitored. Measurements of arterial blood gases and pH were obtained in seven patients. Physiological dead space-tidal volume ratio (VD/VT) was computed. At peak exercise, W vs. C VO(2), VE, and HR values were similar, whereas VCO(2) (848 +/- 69 vs. 1,225 +/- 45 ml/min; P < 0. 001) and lactate (1.5 +/- 0.2 vs. 4.1 +/- 0.2 meq/l; P < 0.001) were lower, DeltaVE/DeltaVCO(2) (35.7 +/- 1.7 vs. 25.9 +/- 1.3; P < 0. 001) and DeltaHR/DeltaVO(2) values (51 +/- 3 vs. 40 +/- 4; P < 0.05) were significantly higher. Analyses of arterial blood gases at peak exercise revealed higher VD/VT and lower arterial partial pressure of oxygen values for W compared with C. In COPD, reduced walking capacity is associated with an excessively high ventilatory demand. Decreased pulmonary gas exchange efficiency and arterial hypoxemia are likely to be responsible for the observed findings.

Pulmonary gas exchange and exercise capacity in patients with systemic lupus erythematosus

OBJECTIVE

Exercise tolerance is often reduced in patients with systemic lupus erythematosus (SLE). Mechanisms have been proposed but the underlying causes have not yet been elucidated. The study of pulmonary gas exchange during exercise may be helpful in revealing circulatory, ventilatory, and metabolic abnormalities. We hypothesized that in SLE, exercise aerobic capacity would be reduced due to chronic inactivity and poor muscle energetics.

METHODS

Thirteen women with SLE and low disease activity were studied; 5 age matched subjects served as controls. Clinical examination, chest radiography, electrocardiogram, and pulmonary function test were all normal. Subjects underwent 1 min incremental cycle ergometer exercise to exhaustion. Oxygen uptake (VO2), CO2 output (VCO2), minute ventilation (VE), heart rate (HR), and arterial O2 saturation were monitored. Anaerobic threshold (AT), VO2/HR, deltaVO2/deltaWatt, respiratory rate (RR), Ti/Ttot, VE/VCO2, and breathing reserve (BR) were computed.

RESULTS

At rest, patients exhibited high VE, respiratory alkalosis, and a wide alveolar-arterial O2 gradient [(A - a)O2] during 50% O2 breathing. Other indexes of respiratory function were within the normal range. In the 6 patients with SLE where pulmonary artery systolic pressure at Doppler echocardiography was measurable, mean level was in the upper limits of normal. During exercise, maximal aerobic capacity was reduced in all patients (VO2 peak, 1098+/-74 vs. 2150+/-160 ml/min, p<0.01; AT, 36 +/-3 vs. 48+/-3% predicted VO2 max, p<0.05). Ventilation adjusted for the metabolic demand (VE/VCO2 at AT) was increased (31+/-1 vs. 24+/-1; p<0.05). A normal breathing pattern was observed during all tests. No patient stopped exercising because of ventilatory limitation (i.e., they had normal breathing reserve).

CONCLUSION

Reduced muscle aerobic capacity is common in SLE and is most likely because of peripheral muscle deconditioning. Increased ventilatory demand, secondary to diffuse interstitial lung disease, is not a significant contributor to the reduction in exercise tolerance.

Somatostatin controls Kaposi's sarcoma tumor growth through inhibition of angiogenesis

Somatostatin and its analogs are active in the inhibition of SST receptor-positive endocrine neoplasms, but their activity and mechanism in nonendocrine tumors is not clear. Somatostatin potently inhibited growth of a Kaposi's sarcoma xenograft in nude mice, yet in vitro the tumor cells did not express any known somatostatin receptors and were not growth inhibited by somatostatin. Histological examination revealed limited vascularization in the somatostatin-treated tumors as compared with the controls. Somatostatin was a potent inhibitor of angiogenesis in an in vivo assay. In vitro, somatostatin inhibited endothelial cell growth and invasion. Migration of monocytes, important mediators of the angiogenic cascade, was also inhibited by somatostatin. Both cells types expressed somatostatin receptor mRNAs. These data demonstrate that somatostatin is a potent antitumor angiogenesis compound directly affecting both endothelial and monocytic cells. The debated function of somatostatin in tumor treatment and the design of therapeutic protocols should be reexamined considering these data.

Effect of reduced body weight on muscle aerobic capacity in patients with COPD

BACKGROUND

Reduced muscle aerobic capacity in COPD patients has been demonstrated in several laboratories by phosphorus magnetic resonance spectroscopy and by analysis of oxygen uptake (VO2) kinetics. COPD patients are usually elderly, hypoxemic, poorly active with muscle atrophy, and often malnourished. Under these conditions there is usually reduction of O2 delivery to the tissues (bulk O2 flow), redistribution of fiber type within the muscle, capillary rarefaction, and decreased mitochondrial function, alterations all capable of reducing muscle aerobic capacity. In COPD, the effect of reduced body mass on muscle aerobic capacity has not been investigated (to our knowledge).

METHODS

We studied 24 patients with stable COPD with moderate-to-severe airway obstruction (68+/-5 [SD] years; FEV1, 39+/-12% predicted; PaO2, 66+/-8 mm Hg; PaCO2, 41+/-3 mm Hg) with poor to normal nutritional status, as indicated by a low-normal percent of ideal body weight (IBW). Each subject first underwent 1-min maximal incremental cycle ergometer exercise for determination of VO2 peak and lactate threshold (LT). Subsequently, they performed a 10-min moderate (80% of LT-VO2) constant load exercise for determination of oxygen deficit (O2DEF) and mean response time VO2 (MRT). VO2, CO2 output (VCO2), and minute ventilation were measured breath by breath.

RESULTS

Patients displayed low VO2 peak (1,094+/-47 [SE] mL/min), LT-VO2 (35+/-3% predicted O2 max), and higher MRT-VO2 (67+/-4 s). Univariate regression analysis showed that percent of IBW correlated with indexes of maximal and submaximal aerobic capacity: vs VO2 peak, R=0.53 (p<0.01); vs MRT R=-0.77 (p<0.001). Using stepwise regression analysis, MRT correlated (R2=-0.70) with percent of IBW (p<0.01) and with PaO2 (p<0.05).

CONCLUSIONS

Reduced body mass has an independent negative effect on muscle aerobic capacity in COPD patients: this effect may explain the variability in exercise tolerance among patients with comparable ventilatory limitation.

Suppression of invasive behavior of melanoma cells by stable expression of anti-sense perlecan cDNA

BACKGROUND

Heparan sulfate proteoglycans are one of the major components of extracellular matrix and are secreted at different levels by several normal and tumoral cells. Perlecan, the basement membrane proteoglycan, has structural domains involved in cell/matrix interactions and growth factor storage. Metastatic melanoma cells show an increase in perlecan expression as compared to low metastatic ones. We examined whether reduction of perlecan expression could down-modulate the malignant phenotype in melanoma clones.

MATERIALS AND METHODS

We transfected B16-F10 murine malignant melanoma cells with a perlecan antisense cDNA construct and tested the in vitro behavior of the selected clones.

RESULTS

The expression of antisense mRNA corresponded to a reduction of perlecan synthesis. The clones with reduced perlecan synthesis showed a down-regulation of proliferation and invasion.

CONCLUSIONS

These results further indicate the importance of perlecan as a regulator of growth factor activity affecting the biological properties of metastatic cells, and suggest the potential use of antisense perlecan DNA in anti-melanoma gene therapy approaches.

The beta-core fragment of human chorionic gonadotrophin inhibits growth of Kaposi's sarcoma-derived cells and a new immortalized Kaposi's sarcoma cell line

OBJECTIVE

Kaposi's sarcoma (KS), a condition often associated with HIV infection, is more common in men than in women; pregnancy and sex hormones could be involved. Urinary human chorionic gonadotrophin (hCG) has been reported to inhibit the growth of KS cell lines, with great variability among preparations. Urinary hCG often contains free forms of the hCG subunits and a fragment of the free beta-subunit, the beta-core, which may have biological activity. We compared the effect of the beta-core fragment, the beta-subunit, recombinant and urinary hCG on KS immortal and spindle cells.

DESIGN AND METHODS

A new immortal KS cell line was phenotypically and karyotypically characterized. The effects on growth of this cell line and of primary KS spindle cells by hCG and its purified derivatives were tested. Induction of apoptosis was demonstrated using acridine orange/ethidium bromide staining.

RESULTS

The beta-core fragment harboured the most potent growth inhibitory activity on a molar basis. After 72 h of treatment with the beta-core, 60-70% of KS cells show apoptotic nuclei. No effects were observed on endothelial cells.

CONCLUSIONS

The beta-core fragment of hCG proved to be the most effective part of the hCG molecule, inducing growth inhibition and apoptosis of KS cells. Thus, the beta-core could be the most appropriate hCG derivative for the therapy of KS.

KSHV sequences in biopsies and cultured spindle cells of epidemic, iatrogenic and Mediterranean forms of Kaposi's sarcoma

The pathogenesis of Kaposi's sarcoma (KS) is still unclear, and several factors appear to be involved in the onset of the Kaposi's lesion. Epidemiological studies suggest that a common infective agent may contribute to KS. Sequences which appear to represent a new gammaherpesvirus, currently termed KSHV/HHV8, have recently been identified in KS. To further examine the relationship between this virus and KS, we obtained biopsy samples of KS lesions; these samples, the spindle cells cultured from these lesions and the PBMC of the same patients were tested for the presence of KSHV sequences by PCR. In addition, we tested several "late passage" KS spindle cell lines as well as control samples. The biopsy samples were from lesions of the following forms of KS: one sporadic KS, two epidemic KS and three iatrogenic KS, one of which was in the process of regressing after reduction of immunosuppressive therapy, and two that were at different stages (patch and nodular) from a single patient. The sporadic KS specimen was positive, as were the PBMCs from this patient, and cells grown from this biopsy appeared to contain KSHV viral sequences up to the fifth passage. Both epidemic KS biopsies were positive, but in these cases KSHV sequences were not detected in the cultured cells. The biopsy from the regressing iatrogenic KS lesion was negative, as were the cells cultured from this lesion. However, the PBMCs of this patient were weakly positive for KSHV at the time of biopsy, and PBMCs collected from this patient one month later were completely negative. The samples of both the patch and the nodular KS lesions obtained from another immunosuppressed patient showed amplifiable sequences of KSHV, but both the PBMCs of this patient and primary KS cell cultures from these biopsies were negative. Of the late-passage KS lines tested, only one, IST AIDS KS 12, was positive for KSHV. This line is derived from an early angiomatous-macula lesion. Taken together, these data suggest that an active KSHV infection is associated with KS and that elimination of KSHV from the lesion precedes regression of the lesion, strongly correlating KSHV with KS. In addition, early KS lesions may have a higher KSHV burden, or contain cells more susceptible to KSHV infection, further linking KSHV to KS.

Isolation of spindle-shaped cell populations from primary cultures of Kaposi's sarcoma of different stage

Cell lines derived both from sporadic and epidemic KS biopsies show similar characteristics: a mixture of mesenchymal and vascular markers as well as production of factors which recruit endothelial cells in vitro and induce neoangiogenesis in vivo. Most established KS spindle cell strains are derived from patch or plaque stage KS lesions, which are easily collected during routine biopsies. Here we have characterized KS-derived spindle cell lines obtained from the four different stages typical of KS progression: angiomatous macula, patch, plaque and nodular KS to show if the similar features of our KS cell lines are linked to a particular stage of progression or to an in vitro selection/differentiation during KS cell culture. These four KS cell lines have shown the same pattern of characterization as the previous established KS cell lines, apart from an early selection of the spindle cell population we have also observed an easy inducible phenotypic differentiation through a myofibroblastic spindle cell type simply plating cells on gelatin-coated flasks. These data confirm the hypothesis of spindle cell selection in culture and the possible differentiation of these mesenchymal cells.

The alpha 3 beta 1 integrin is involved in melanoma cell migration and invasion

The VLA3 (alpha 3 beta 1) integrin receptor recognizes several ligands; however, the function of this integrin is still debated. Expression of VLA3 appears to be increased in malignant melanoma and correlates with the degree of dermal invasiveness. Here we have studied the role the alpha 3 integrin subunit in malignant melanoma cell migration and invasion into extracellular matrices. The 2/14 clone of the Me665/2 human melanoma cell line, which expresses high levels of VLA integrins, was highly migratory and invasive, while the low integrin expressing 2/56 clone showed limited migration and was not invasive. Antibodies to the beta 1 subunit inhibited adhesion, migration, and invasion of two different malignant melanoma cell lines, the 2/14 clone and A2058 cells, indicating a crucial role for VLA integrins in these phenomena. While anti-alpha 6 antibodies inhibited adhesion to laminin and anti-alpha 5 antibodies inhibited adhesion to fibronectin, antibodies to the alpha 3 subunit did not inhibit adhesion of these cells to laminin, fibronectin, or collagen i.v. In contrast, the P1B5 anti-alpha 3 antibodies were good inhibitors of the migration of these cells toward laminin, fibronectin, and collagen IV and also blocked invasion of these cells through a reconstituted basement membrane matrix (Matrigel). Another anti-alpha 3 antibody, F4, did not effect migration, while both the P1B5 and F4 antibodies induced cellular aggregation on Matrigel. Our data suggest a specific role for alpha 3 beta 1 in the migration and invasion of melanoma cells.

Oxygen effect on O2 deficit and VO2 kinetics during exercise in obstructive pulmonary disease

We evaluated the effect of supplemental O2 on energy metabolism of hypoxemic humans by measuring O2 uptake (VO2) kinetics and other cardiorespiratory parameters in nine male chronic obstructive pulmonary disease (COPD) patients and seven age-matched control subjects (on air and on 30% O2) at rest and during moderate cycle ergometer exercise. Heart rate, ventilation, VO2, CO2 output, respiratory exchange ratio, O2 cost of work, and work efficiency were measured with a computerized metabolic cart; O2 deficit and VO2 time courses were calculated. In COPD patients, 30% O2 breathing resulted in 1) reduction of O2 deficit (from 488 +/- 34 ml in air to 398 +/- 27 ml in O2; P < 0.05) and phase 2 VO2 time constant (from 116 +/- 13 s in air to 74 +/- 12 s in O2; P < 0.05); 2) a smaller steady-state increment in CO2 output than in room air (315 +/- 17 ml/min in O2 vs. 358 +/- 27 ml/min in air; P < 0.02), which resulted in a lower exercise respiratory exchange ratio (0.75 +/- 0.02 in O2 vs. 0.80 +/- 0.02 in air; P < 0.02); and 3) reduced steady-state ventilation (22.6 +/- 1.0 l/min in O2 vs. 25.4 +/- 1.1 l/min in air; P < 0.05). In conclusion, 30% O2 breathing accelerated exercise VO2 kinetics in mildly hypoxemic COPD patients. The observed VO2 kinetics improvement with O2 supplementation is consistent with an enhancement of aerobic metabolism in skeletal muscles during moderate exercise.

Nutritional state and exercise tolerance in patients with COPD

We hypothesized that in patients with COPD, poor nutritional status adversely influences exercise tolerance by limiting aerobic capacity of exercising muscles. In 28 patients with stable COPD, we correlated nutritional status with gas exchange indexes obtained during maximal incremental cycle ergometer exercise and with respiratory function parameters. On the basis of percent of ideal body weight (%IBW), patients were divided into three groups (GP): GP1 (n = 8, %IBW < 90); GP2 (n = 13, %IBW > or = 90 < 110); and GP3 (n = 7, %IBW > or = 110). When compared with normally nourished individuals (GPs 2 and 3), malnourished GP1 patients showed greater reduction in maximal workload and in peak O2 uptake (VO2 peak), with earlier onset of metabolic acidosis (anaerobic threshold [AT]); in addition, indexes reflecting O2 cost of ventilation were higher in GP1. Nutritional status could be correlated with exercise tolerance (VO2 peak, r = 0.82, p < 0.0001), with onset of metabolic acidosis (AT, r = 0.69, p < 0.0001) and with dead space/tidal volume ratio (VD/VT, r = -0.59, p < 0.001). Body weight was inversely correlated with indexes that are likely to reflect the increase in O2 cost of ventilation. We conclude that in patients with stable COPD, (1) malnutrition significantly affects muscle aerobic capacity and exercise tolerance, and (2) high wasted ventilation and O2 cost of ventilation may be responsible for the weight loss.

Establishment and characterization of two new Kaposi's sarcoma cell cultures from an AIDS and a non-AIDS patient

We have established and characterized two new Kaposi's sarcoma (KS) cell lines derived from skin biopsies: AIDS-KSISTIV (from an AIDS-associated KS) and KSISTVIII (from a sporadic KS). AIDS-KSISTIV and KSISTVIII are composed mostly of spindle-shaped cells. They show similar patterns of immunohistochemical staining and are positive for smooth muscle (smooth muscle alpha-actin) and fibroblastoid (TE7) markers. Neither of these lines express the endothelial marker von Willebrand factor VIII. These immunohistochemical patterns are similar to numerous other KS lines that we and others have established. When seeded on a reconstituted basement membrane ("Matrigel"), AIDS-KSISTIV and KSISTVIII cells form branching colonies and invade into the Matrigel, as do other KS cultures that we have previously examined. This behaviour on Matrigel is similar to that of malignant sarcoma cells of different origin. The expression of vimentin and the morphology of the invasive colonies on Matrigel suggest that KS-derived cells are poorly differentiated mesenchymal cells. KS lesions are characterized by a conspicuous neovascularization, which appears to be derived from host cell recruitment. We tested the capability of the KS-cell supernatants to induce an angiogenic response in vitro. The new lines are able to stimulate human endothelial cell chemotaxis and invasion through Matrigel-coated filters. No differences in angiogenic potential in vitro were observed between the AIDS and the non-AIDS case, as we previously noted for other established cultures. Our new lines have the properties of true KS cells and confirm that KS spindle cells from HIV-positive or -negative patients have identical phenotypic and behavioural characteristics in vitro.

Cardiopulmonary exercise testing in the evaluation of patients with ventilatory vs circulatory causes of reduced exercise tolerance

INTRODUCTION

Cardiopulmonary exercise testing (CPX) is considered a useful procedure in the evaluation of circulatory, ventilatory, or mixed origin of reduced exercise tolerance. Our study was designed to compare CPX and a standard clinical-instrumental approach in the evaluation of patients with cardiopulmonary disorders.

METHODS

Fifty-seven patients (31 male, 26 female; mean [+/- SE] age, 60 +/- 2 years) were studied. Each patient was evaluated by two different observers: one used standard clinical criteria, the other used gas exchange indexes, monitored during a maximal incremental CPX, performed on a cycle ergometer. Cardiac output (CO), at rest and at submaximal work level, was also obtained.

RESULTS

In 46 patients (80.7 percent), a concordant evaluation was reached by the two observers (24 were found to have a predominant ventilatory disorder, 22 to have a circulatory disorder); among these, in subjects considered to have circulatory impairment, the maximal CO/maximal workload ratio was significantly lower than in the ventilatory group; in those with ventilatory impairment, the reduced exercise tolerance correlated with the resting spirometric values. In the remaining 11 patients (19.3 percent), CPX better defined the underlying pathophysiology of exercise limitation: in 10 of them, clinically classified as having a mixed or predominantly ventilatory disorder, a greater importance of the circulatory component was detected; 4 had evidence of pulmonary vascular impairment (high VE/VCO2 at anaerobic threshold).

CONCLUSIONS

Our study confirmed the sensitivity of CPX in the evaluation of a reduced exercise tolerance in dyspneic patients with cardiopulmonary conditions; when compared with a clinical-laboratory approach, in some patients it allowed the detection of an underestimated circulatory component causing exercise limitation.

Characterization of kaposis sarcoma-derived cell-cultures from an epidemic and a classic case

Cells derived from skin biopsies from two Kaposi's sarcoma patients, an elderly female with a sporadic non-AIDS form, and an AIDS-affected homosexual male, were established in culture. The classic patient had a few small lesions, while the epidemic case presented-large, disseminated, cutaneous and oral mucosa lesions. The cells obtained from both patients, termed IST-KS2 and AIDS-IST-KS3 respectively, had the characteristic spindle shape reported for Kaposi's sarcoma-derived cells. By immunocytochemistry they were both found to express the smooth muscle specific isoform of alpha actin. The KS cells expressed the fibroblastic antigen TE-7, which is not expressed in endothelial cells. Furthermore both KS cultures were negative for the endothelium associated markers Factor VIII, EN4 and PAL-E. They were also negative for the leukocyte antigen CD45, but were positive for vimentin. Immunocytochemistry studies were therefore suggestive of a primitive mesenchymal cell. When the KS-derived cells were grown on a gel of reconstituted basement membrane, both cultures formed large branching colonies characteristic of malignant cells of mesenchymal origin. No differences were observed between HIV-related and the sporadic KS-derived cultures studied. Fibroblasts and smooth muscle cells did not form branching colonies, while endothelial cells on matrigel differentiated forming tube-like structures. Supernatants from both sporadic and AIDS-related KS cell cultures had similar effects on endothelial cell growth in vitro and were also found to stimulate chemotaxis and chemoinvasion of normal vascular endothelial cells in the Boyden chamber assay, showing angiogenic potential in vitro. Our results demonstrate that long term cultures of spindle shaped cells derived from either HIV-associated and classic KS show the same histocytochemical phenotype, have invasiveness in matrigel similar to that of malignant sarcomas, and share in vitro angiogenic properties. Therefore, factors from the host are likely to be responsible for the divergent clinical picture of the classic and epidemic Kaposi's patients studied here.

Regulation of atrial natriuretic peptide release in normal humans

Atrial volume, pressure, and heart rate are considered the most important modulators of atrial natriuretic peptide (ANP) release, although their relative role is unknown. Continuous positive-pressure breathing in normal humans may cause atrial pressure and atrial volume to go in opposite directions (increase and decrease, respectively). We utilized this maneuver to differentially manipulate atrial volume and atrial pressure and evaluate the effect on ANP release. Effective filling pressure (atrial pressure minus pericardial pressure) was also monitored, because this variable has been proposed as another modulator of ANP secretion. We measured right atrial (RA) pressure, RA area, esophageal pressure (reflection of pericardial pressure), and RA and peripheral venous ANP in seven healthy adult males at rest and during continuous positive-pressure breathing (19 mmHg for 15 min). Continuous positive-pressure breathing decreased RA area (mean +/- SE, *P less than 0.05) 13.6 +/- 1.1 to 10.5 +/- 0.8* cm2, increased RA pressure 4 +/- 1 to 16 +/- 1* mmHg, increased esophageal pressure 2 +/- 1 to 12 +/- 1* mmHg, and increased effective filling pressure 2 +/- 0 to 4 +/- 1* mmHg. RA ANP increased from 67 +/- 17 to 91 +/- 18* pmol/l and peripheral venous ANP from 43 +/- 4 to 58 +/- 6* pmol/l.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacologic elevation of blood inorganic phosphate in hypoxemic patients with COPD

We have shown that in patients with COPD, myocardial efficiency during exercise is enhanced following acute elevations of plasma phosphate (Pi). A decrease in Hb-O2 affinity (increase in P50) was not responsible for the improvement. We postulated that the physiologic benefit was due to the acute reversal of a subclinical myocardial Pi depletion. To further test this hypothesis in a chronic state, we studied nine stable hypoxemic (PaO2 = 64 +/- 2 mm Hg [+/- SEM]) patients with COPD over five weeks: two weeks at normal plasma Pi; and three weeks at elevated plasma Pi, induced by etidronate disodium (Didronel; 750 mg orally daily). Administration of etidronate disodium increased (p less than 0.05) plasma level of Pi (4.4 +/- 0.2 to 5.8 +/- 0.1 mg/dl), RBC level of Pi (3.1 +/- 0.2 to 4.1 +/- 0.2 mg/dl), RBC level of 2,3-DPG (16.2 +/- 1.1 to 21.3 g+/- 1.3 mumol/g of Hb) and P50 (23.7 +/- 0.5 to 26.0 +/- 0.8 mm Hg). At the end of the treatment, the widening of the C(a-v)O2 with exercise (7.1 +/- 0.8 to 8.9 +/- 0.6 ml/dl) was less pronounced than under control conditions (6.9 +/- 0.4 to 10.1 +/- 0.6 ml/dl; p less than 0.02); concomitantly, the crossover point (COP; the PaO2 below which a rightward-shifted Hb-O2 curve causes the C(a-v)O2 to become narrower rather than wider) increased (37 +/- 2 to 49 +/- 1 mm Hg). Indicators of myocardial work efficiency were not affected by etidronate disodium at rest or during exercise. We postulate that during exercise the potential beneficial effect of the rightward shift of the Hb-O2 curve upon cardiac function was negated by the fall of PaO2 to or below the COP level, a situation which would limit increases in tissue O2 extraction.

Alveolar cell population in HIV infected patients

Alveolar lymphocytosis, in the face of blood lymphopenia, is a common finding among patients with AIDS. We studied by bronchoalveolar lavage (BAL), the alveolar cell profile of 43 human immuno deficiency virus (HIV) seropositive patients divided into three groups involving the advanced stages of the disease: group A (n = 9; CDC III), ambulatory individuals without systemic or respiratory symptoms; group B (n = 15; CDC IV) patients admitted for evaluation of fever of unknown origin (FUO) without pulmonary involvement; group C (n = 19; CDC IV), patients admitted for evaluation of an acute pulmonary condition. Sex, age and risk factor were comparable among the groups. Alveolar lymphocytosis was found in no group A patients, in 2 out of 15 group B patients (both with P. carinii lung infection) and in all group C patients, where pulmonary involvement was due to opportunistic infection or to nonspecific interstitial pneumonitis. Our findings suggest that in patients with advanced HIV infection alveolar lymphocytosis may be an expression of a concomitant process within the lungs either clinically manifest or inapparent, or possibly related to HIV primary lung involvement.

Alveolar cell population in HIV infected patients

Alveolar lymphocytosis, in the face of blood lymphopenia, is a common finding among patients with AIDS. We studied by bronchoalveolar lavage (BAL), the alveolar cell profile of 43 human immuno deficiency virus (HIV) seropositive patients divided into three groups involving the advanced stages of the disease: group A (n = 9; CDC III), ambulatory individuals without systemic or respiratory symptoms; group B (n = 15; CDC IV) patients admitted for evaluation of fever of unknown origin (FUO) without pulmonary involvement; group C (n = 19; CDC IV), patients admitted for evaluation of an acute pulmonary condition. Sex, age and risk factor were comparable among the groups. Alveolar lymphocytosis was found in no group A patients, in 2 out of 15 group B patients (both with P. carinii lung infection) and in all group C patients, where pulmonary involvement was due to opportunistic infection or to nonspecific interstitial pneumonitis. Our findings suggest that in patients with advanced HIV infection alveolar lymphocytosis may be an expression of a concomitant process within the lungs either clinically manifest or inapparent, or possibly related to HIV primary lung involvement.

Incidence of acid-base and electrolyte disturbances in a general hospital: a study of 110 consecutive admissions

To establish the overall frequency distribution and combination of acid-base and electrolyte disturbances as they occur in a general population requiring hospital care, we studied arterial blood gases and plasma electrolytes (sodium, potassium and chloride) in 110 consecutive patients (age = 68 +/- 8 SE; 64 M, 46 F) at the time of admission to a general medical ward. Disturbances were defined on the basis of the standard pH/pCO2 plot and the normal (mean +/- 2 SD) electrolyte range for our laboratory. Sixty-two patients (56%) showed a disturbance in acid base equilibrium: acidosis: respiratory 16, metabolic 6; alkalosis: respiratory 26, metabolic 10; in 4/62 the acid base disturbance was mixed. In 47 of the 62 patients, the acid base imbalance were associated with electrolyte derangements (low PNa+, 12; high PNa+, 1; low PK+, 10; high pK+, 7; increased anion gap, 17). Electrolyte disturbances with a normal acid base status were detected in only 2 patients. Of significance, in 7 of the 58 individuals considered to have a "pure" acid base disturbance on the basis of the pH/pCO2 plot (5 respiratory alkalosis; 1 respiratory acidosis; 1 metabolic alkalosis), a widened anion gap revealed that the acid-base change was mixed, i.e. there was a concomitant component of metabolic acidosis. Thus, the total number of mixed acid base equilibrium disorders were eleven. This study emphasizes the frequent incidence of acid base and electrolyte disorders, very often in combination, among unselected adult patients admitted to a general medical ward. In addition it reinforces that a high prevalence of hidden cases of mixed acid base disturbances can be recognized by concomitant analysis of acid base and electrolyte parameters, including anion gap calculation.

Effect of positive and negative pressure breathing on sodium and water excretion

Positive and negative pressure breathing purportedly alter renal sodium and water excretion by modifying hemodynamics and/or hormonal regulators of sodium and water homeostasis. To test this hypothesis we monitored hemodynamic and hormonal responses in seven normal men to (1) continuous positive pressure breathing (19 +/- 1 mm Hg for 30 minutes) after water loading (urine volume = 15 +/- 1 ml/min); and (2) continuous negative pressure breathing (11 +/- 1 mm Hg for 30 minutes) after maintenance water ingestion (urine volume = 4 +/- 1 ml/min), in random order. Each study was repeated on a control day without pressure breathing. Results were as follows (mean +/- SE, p less than 0.05): (1) continuous positive pressure breathing decreased urinary sodium from 0.28 +/- 0.07 to 0.17 +/- 0.04 mEq/min, increased atrial natriuretic peptide from 34.2 +/- 4.9 to 48.5 +/- 6.9 pg/ml, and had no effect on osmolar and free water clearances, cardiac output, plasma renin activity, or plasma aldosterone and plasma arginine vasopressin levels; and (2) continuous negative pressure breathing increased free water clearance from 0.6 +/- 0.7 to 4.5 +/- 1.2 ml/min, urine volume from 4.0 +/- 0.8 to 8.9 +/- 1.3 ml/min, and cardiac output from 5.1 +/- 0.4 to 7.0 +/- 0.6 L/min in a proportional manner (r = 0.40, p less than 0.01) and had no effect on osmolar clearance, urinary volumes of sodium and potassium, plasma renin activity, plasma aldosterone, atrial natriuretic peptide, and arginine vasopressin.(ABSTRACT TRUNCATED AT 250 WORDS)

[Use of reconstituted basal membranes for the study of invasion of human tumor cells: current status and future prospects]

Tumor metastasis is the major cause of death of oncology patients. One of the characteristic properties acquired by the metastatic cell is the ability to cross basement membranes. These are compartments of extracellular matrix composed largely by collagen type IV, laminin and a heparan sulphate proteoglycan. Here we review the use of a reconstituted basement membrane (Matrigel) in the Boyden chamber assay (Chemoinvasion Assay) for the assessment of the invasiveness of tumor cells of human origin. The possibility of using this test for the rapid evaluation of human tumor specimens from operated patients is discussed.

Effect of vitamin A on chemotactic and chemoinvasive behaviour of an osteosarcoma cell line

Vitamin A is known to be able to modulate cell growth and differentiation and to act as an inhibitor of the process of carcinogenesis in some experimental models. Here we have studied the effect of different concentrations of vitamin A on chemotactic and chemoinvasive behaviour of a metastatic osteosarcoma cell line. The cell proliferation was partially inhibited in the presence of 10(-5) M retinol after 4 days of incubation. Retinol effect on chemotactic and chemoinvasive activity of osteosarcoma cells seemed to be dose-dependent. The highest retinol concentration used (10(-5) M) had an inhibitory effect on migratory and invasive cell response. Lower retinol concentrations seemed to be able to enhance (10(-8) M) both chemotactic and chemoinvasive activity of osteosarcoma cells. Chemotaxis and chemoinvasion assays provide rapid and quantitative tools to study the "in vitro" behaviour of metastatic cells. Furthermore, they represent a mean to screen for drugs, hormones and other substances able to alter the metastatic phenotype.

The effect of oxygen on sodium excretion in hypoxemic patients with chronic obstructive lung disease

In advanced chronic obstructive lung disease (COLD), sodium retention is common, associated with reduction in renal plasma flow (RPF) and stimulation of the renin-aldosterone (PRA-PA) system, two abnormalities due to or influenced by hypercapnia: the independent role of hypoxemia in perturbing sodium homeostasis is unknown. In five stable patients with COLD (FEV1 = 0.9 +/- 0.21, mean +/- SE) with mild edema, during two weeks of a low sodium diet (one week on room air: pH = 7.39 +/- 0.02; PaO2 = 55 +/- 4 mm Hg; PaCO2 = 49 +/- 4 mm Hg; and one week on O2: pH = 7.38 +/- 0.01; PaO2 = 72 +/- 6 mm Hg; PaCO2 = 52 +/- 4 mm Hg) we monitored sodium balance, systemic and renal hemodynamics, plasma sodium and potassium, PRA, PA, and atrial natriuretic hormone (ANH). During air breathing, patients uniformly showed a depression of RPF despite normal cardiac output; plasma hormone levels did not differ from controls but there was elevation (greater than 2 SD above the normal mean) of PRA in four patients, PA in two patients, and ANH in two of five patients. During O2 breathing, urinary sodium increased significantly from 67 +/- 7 to 102 +/- 10 mEq/24 h. Surprisingly, the patients experienced a small but significant weight gain (0.6 +/- 0.1 kg). None of the other variables was affected by O2 therapy. The following conclusions were reached: in advanced COLD, correction of hypoxemia results in sodium diuresis, indicating that hypoxemia (in the presence of hypercapnia) contributes to sodium retention. The mechanism for this beneficial effect of O2 will require further investigation.

Invasiveness and chemotactic activity of oncogene transformed NIH/3T3 cells

The role of oncogenes in the acquisition of invasive and metastatic capabilities is controversial. Interactions with basement membranes are critical in the process of tumor invasion and metastasis. We compared the ability of 3T3 cells transformed by oncogenes involved in various stages of signal transduction to invade a reconstituted basement membrane in vitro and to grow in a three dimensional basement membrane gel (matrigel). Cell lines transformed by various oncogenes and oncoviruses: v-sis (a growth factor), v-erb-B (a truncated EGF receptor), Moloney sarcoma virus (v-mos: a protein kinase homologue), mutated c-ras oncogenes (G protein homologues), FBJ virus (v-fos: a nuclear protein) were investigated. All transformed cell lines were able to invade in the chemoinvasion assay, where a layer of matrigel is coated onto chemotaxis filters. FBJ/3T3 were the least invasive and SSV/3T3 the most invasive. Control 3T3 cells could not cross the matrigel barrier. All transformed cells grew on matrigel forming invasive, branching colonies, whereas control 3T3 were unable to grow in matrigel. Cells transfected with the v-erb-B gene grew as multilayers inside matrigel. Invasiveness and growth on matrigel were accompanied by a high chemotactic response to laminin (LN) in all transformed lines. These results suggest that invasion and growth on matrigel, together with migration to LN, are induced by a large spectrum of oncogenes. When 3T3 cells were transfected with v-sis oncogene under the transcriptional control of the metallothionein (MMT) promoter and exposed to Zn++, their in vitro invasiveness was specifically increased by around 3 fold. These findings provide further evidence supporting a direct role of the v-sis oncogene in the invasive phenotype.

Atrial natriuretic peptide, renin and aldosterone in obstructive lung disease and heart failure

Elevations of atrial natriuretic peptide (ANP) in congestive heart failure (CHF) and chronic obstructive lung disease (COLD) are presumably due to atrial hypertension, while secondary hyperaldosteronism in these patients is thought to result from diminished renal perfusion. The responsiveness of the ANP and renin (PRA)-aldosterone (PA) systems to acute increases in right atrial pressure has not been studied in these patients, but in normals a reciprocal relationship between ANP with PRA and PA has been shown. The authors monitored venous pressure (VP, reflective of right atrial pressure), ANP, PRA and PA in 15 stable COLD patients, seven stable CHF patients and three normal controls at baseline and after elevation of VP by antishock trousers. Inflation of the trousers resulted in increased VP and ANP (p less than 0.05): control ANP, 84 +/- 17 to 108 +/- 23 pg/ml; COLD ANP, 176 +/- 5 to 200 +/- 7; and CHF ANP, 388 +/- 20 to 499 +/- 37. PRA and PA were not suppressed by increasing ANP levels and the delta ANP/delta VP ratio was similar among groups. No intergroup differences in resting PRA and PA were noted, but PRA was higher (p = 0.007) and PA tended to be higher (p = 0.08) in a sub-group of six edematous patients, as compared with non-edematous patients and controls. These findings: (1) confirm previously reported ANP differences between COLD and CHF; (2) indicate that the ANP system remains responsive to physiologic manipulations in COLD and CHF; and (3) demonstrate that ANP and the PRA-PA axis are not reciprocally related in either group.

Growth of cells from esophageal squamous cell carcinoma biopsies in a reconstituted basement membrane

Cells from esophageal carcinoma biopsies were cultured on or inside a three-dimensional basement membrane matrix (matrigel). Their growth was compared to cells derived from control esophageal biopsies. Cells from both normal and neoplastic tissue attached poorly to tissue culture plastic. Matrigel coating improved adhesion and growth. When cells were grown inside a matrigel matrix, a striking difference was noticed between carcinoma cells and controls. Carcinoma cells grew invasively in the three-dimensional substrate and digested the matrix after a few weeks; control cells did not grow and only a few necrotic cells were visible with time. Matrigel provided a better growth substrate than plastic for esophageal derived cells and discriminated between carcinoma-derived and control cells when used as a three-dimensional growth substrate. Our studies suggest a possible use of matrigel for the selective growth of tumor cells derived directly from tissue biopsies.

Effects of fenoterol on oxygen transport in patients with chronic airflow obstruction

A rise in cardiac output and a fall in arterial oxygen tension are well known side effects of bronchodilator drugs, particularly beta-adrenergic agonists. In recent years, fenoterol (Berotec), an effective beta-adrenergic agonist, has been used at increasing rates in asthmatic subjects, as well as in patients with chronic obstructive pulmonary disease (COPD). The effects of fenoterol on systemic hemodynamics or arterial oxygenation (or both) in patients with COPD have not been investigated; in these individuals, who often have increased sympathetic tone and hypoxemia even at rest, cardiovascular stimulation and a fall in arterial oxygen tension would be particularly undesirable side effects. In 14 patients with COPD (seven without a reversible component of airflow obstruction [group 1]; and seven with a reversible component of airflow obstruction [group 2]), we studied all of the important parameters of oxygen transport before and 60 minutes after administration of fenoterol. Studies were performed at rest and after exercise. At baseline, group 1 showed a faster heart rate, a lower cardiac output, a lower arterial oxygen flow, a wider arteriovenous oxygen content difference (C[a-v]O2), and a higher fraction of oxygen extracted by the tissues from a given arterial oxygen flow. In both groups, all measured parameters, including cardiac output and arterial oxygen pressure (PaO2) remained statistically unchanged one hour after administration of fenoterol; with exercise, the heart rate, blood pressure, minute ventilation, oxygen consumption, C(a-v)O2, and the percentage of oxygen extracted from arterial oxygen flow, as well as cardiac output and PaO2, increased in all instances; the exercise responses were not affected by the drug. These results suggest that at the time of its maximal effect on the airways (60 minutes), fenoterol has no untoward effect on the oxygen transport system, at rest or during exercise, in patients with COPD with or without a reversible component.

Effect of inorganic phosphate in hypoxemic chronic obstructive lung disease patients during exercise

We have shown that normal subjects exercise more efficiently with increased plasma phosphate, presumably due to decreased hemoglobin-oxygen affinity and thus enhanced tissue O2 extraction. We subjected nine stable hypoxemic COLD patients to exercise at 0 (control), 24 (experimental) and 48 hrs (recovery) after phosphate infusion. Baseline variables were identical for each time period. Exercise responses at 0 and 48 hours were also indistinguishable. Exercise response at 24 hrs differed from those at 0 and 48 hours as follows: widening of A-V O2 content difference was more pronounced (28 +/- 6 vs 15 +/- 6 ml/L, p less than 0.03) and the increment in tissue O2 extraction was larger (14 +/- 3 vs 8 +/- 3 percent, p less than 0.03). P50 and related variables did not change during the course of the study. Thus, like normal subjects, hypoxemic patients stimulated with phosphate administration can exercise perhaps more efficiently; but, in contrast to normal subjects, this effect cannot be attributed to changes in hemoglobin-oxygen affinity. These data suggest that phosphate administration may be beneficial in hypoxemic states where adequate tissue oxygenation cannot be achieved by other more conventional methods. The mechanism of this effect remains to be elucidated.

Characterization of the effects induced on DNA in mouse and hamster cells by lithocholic acid

Lithocholic acid (LCA) is a promoting agent in colon carcinogenesis. In this work we have tried to characterize the DNA alteration induced by LCA in cells grown in vitro and in nuclei. Confirming previous findings, a clear increase in elution rate was observed at both alkaline and neutral pH. The extent of the increase was very similar at the two pHs. However, an increased elution rate could be observed only when lysing the nuclei at high ionic strength and low detergent concentration (2 M NaCl + 0.2% N-lauroylsarcosine sodium salt). No effect could be observed when the nuclei were lysed with a high detergent concentration (2% sodium dodecyl sulfate). In addition, a slight effect could be observed using a method for the evaluation of DNA unwinding in alkali. After termination of the incubation with LCA, the DNA alteration observed with DNA elution disappeared very rapidly both in intact cells and nuclei, even when the incubation buffer was totally unsuitable for the repair of the type of DNA damage induced by typical genotoxic agents. The effect of LCA on DNA was apparently not mediated through an inhibition of topoisomerase II. Only the intact chromatin of nuclei was responsive, not the quasinaked DNA of nuclei lysed at high ionic strength. We advance the hypothesis that the increased alkaline and neutral elution rate observed with LCA could be independent of DNA fragmentation and related to changes in chromatin structure.

Tolerance to inhaled Duovent. A long-term study

Fenoterol with ipratropium bromide (Duovent) is a recently used combination between an anticholinergic and a beta-adrenergic drug useful in obtaining a more effective bronchodilatation and/or reducing the single drug doses. It has been suggested that, as in the case of beta-agonists, its clinical efficacy may be limited by the development of tolerance. We studied the effects of inhaled Duovent in 15 asthmatic patients for 3 months, using a rigidly controlled protocol. Appropriate serial physiological measurements were made at regular intervals during the 90-day study. In all instances the day-one bronchodilator response was significant, prompt and sustained: at 1, 4, 8 and 12 weeks the response was statistically the same as on day 1. It is concluded that, when the important variables are properly controlled, no evidence of tolerance to long-term therapy with Duovent is demonstrable.