What is the best management for abdominal aortic aneurysm in patients at high surgical risk? A single-center review

AIM

To determine the best treatment for high-risk patients with abdominal aortic aneurysms (AAA).

METHODS

We reviewed a prospective database of all patients who underwent conventional (OPEN) or endovascular aneurysm repair (EVAR) between January 1998 and December 2002. Patients were preoperatively classified according to the American Society of Anesthesiology (ASA). Comorbidities and medical risk factors were categorized according to the Ad Hoc Committee on Reporting Standards. Perioperative mortality and morbidity rates were analyzed according to the type of surgical procedure (OPEN vs EVAR) and ASA class. Patients in ASA classes I and II were excluded. Continuous data were expressed as mean +/- standard deviation. All data were calculated using the cumulated actuarial method of event outcome probability. Kaplan-Meier curves were constructed and the log-rank statistic and chi squared test were used for comparative data. P values less than 0.05 were considered to indicate statistical significance.

RESULTS

Of the total 375 patients who underwent AAA repair, 168 (45%) belonged in ASA classes III and IV (85 submitted OPEN and 83 EVAR to repair). Among general risk factors only coronary artery disease differed significantly between the 4 groups (P = 0.04). The Bonferroni correction identified a statistically significant difference between ASA classes III and IV for the OPEN technique and for EVAR (P = 0.007 and P = 0.012). Neither 30-day morbidity or mortality differed significantly according to ASA class and surgical technique. The median follow-up was 19 months (range 5-60 months). The overall survival was 78% at 60 months. Survival rates during follow-up differed significantly in the 2 risk classes (ASA III 5/123, 4% vs ASA IV 9/38, 24%), (P = 0.0001). The deaths in the ASA class 4 patients (12/14; 86%) were caused by preexisting medical comorbidities (in 9 patients cardiovascular, in 1 cancer and in 2 cirrhosis).

CONCLUSIONS

Except patients with small aneurysms (< 6 cm), in whom the risk of death at 1-year due to comorbidities exceeds the risk of a ruptured aneurysm, all patients at high surgical risk (ASA class IV) benefit from AAA repair. Patients with small aneurysms must undergo strict surveillance to assess growth and aneurysmal wall changes to prevent unexpected rupture.

[Monitoring of canine leishmaniasis in northern Italy: an update from a scientific network]

Canine leishmaniasis (CanL) due to Leishmania infantum is a disease of great veterinary importance and a serious public health problem. In humans, L. infantum causes visceral (VL) and cutaneous leishmaniasis (CL) and the distribution of VL overlaps that of CanL. Currently, VL is considered by WHO as an emerging zoonosis in southern Europe. The dog is the only domestic reservoir of the infection and phlebotomine sandflies are the only proven vectors of leishmaniasis for dogs and humans. CanL is endemic in Italy, particularly in central and southern regions, including islands. Until 1983, all regions of northern Italy but Liguria and some territories of Emilia Romagna were considered free from CanL. From early '90s new stable foci of CanL have appeared, most of them located within classical endemic areas including territories of Emilia Romagna, Tuscany, Umbria, Marche, and Abruzzi regions. But the most relevant aspect, from an epidemiological point of view, has been the appearance of stable CanL foci in northern Italy, namely in Veneto and Piedmont regions. In these two foci, entomological surveys showed the presence of P. perniciosus and of a second phlebotomine vector, P. neglectus, which may have played a role in the CanL diffusion in some parts of northern Italy. Furthermore, in these areas, autochthonous human VL cases have occurred. There is therefore a realistic risk that CanL infection could rapidly spread through northern latitudes and a surveillance activity is strongly needed. For this reason, in October 2002, thanks to the collaboration and support of Intervet Italia, the network "LeishMap" was created, with the main purpose of monitoring the spread of CanL and vectors in northern Italy. LeishMap consists of scientific and sanitary institutions with proven experience both in field surveys and diagnostic methodologies on CanL and phlebotomine vector. It is organised in 4 Operational Units (OU), represented by researchers of the Veterinary Faculties of the University of Bologna, Padua, Milan and Turin, under the scientific coordination of the MIPI Department, ISS of Rome and with the collaboration of private and public veterinarians operating in the regions under study. During the first year of activity, each OU was involved in the serological and entomological surveillance of several territories in the respective regions, where recent autochthonous CanL cases were registered. The studies have involved five regions, namely Valle D'Aosta, Piedmont, Lombardia, Veneto, Trentino-Alto Adige and Emilia Romagna. In the Symposium 6 of this Congress we report detailed results of a retrospective analysis of data concerning CanL and vectors in northern Italy till 2002 and the preliminary results of 2003 on the seroprevalence rates observed in foci studied and on the entomological surveys carried out. In summary, the results outlined that already known foci of CanL are expanding from the original sites. Several new foci have been identified and many others are at high risk of evolving toward a stable endemicity. P. perniciosus has been found in all but one the suspected new foci. In Emilia Romagna region P. perfiliewi was identified in 2 areas and in one was the only species present. The occurrence of P. neglectus was confirmed in three regions, Veneto, Lombardia and Piedmont. In conclusion, from the 2002-2003 LeishMap activities it appears that further monitoring activities are necessary to identify new endemic foci of CanL, this representing the prerequisite for the implementation of programs for leishmaniasis control in northern Italy.

Modification of plasma glycosaminoglycans in long distance runners

BACKGROUND

It is well documented that exercise reduces the risk of thromboembolic disease, possibly by increasing the plasma concentration of anticoagulant-antithrombotic compounds.

OBJECTIVES

As plasma glycosaminoglycans (GAGs) play a role in the anticoagulant-antithrombotic potential of plasma, to examine the concentration and profile of these compounds in well trained, long distance runners and sedentary subjects.

METHODS

Plasma GAGs were measured in 10 male, long distance runners and 10 sedentary counterparts before and after ergometric tests. GAGs were extracted, purified, and identified by electrophoretic and enzymatic methods, and measured as hexosamine.

RESULTS

Plasma GAGs found in sedentary subjects were slow migrating heparan sulphates I and II, keratan sulphate I, and chondroitin 4-6-sulphate. Those found in trained athletes were slow migrating heparan sulphate I, chondroitin 4-6-sulphate (or keratan sulphate I), and fast migrating heparan sulphate. Total plasma concentrations of GAGs were higher in athletes than in sedentary subjects at rest. In sedentary subjects, plasma GAGs did not change after cycle ergometric exercise at 80% of their anaerobic threshold. However, the appearance of a novel band of heparan sulphate migrating faster than fast migrating heparan sulphate was observed in athletes after exercise.

CONCLUSIONS

Exercise changes the amount and profile of plasma GAGs; these changes may play a role in protecting subjects who practise aerobic sports against developing cardiovascular disease.

The importance of suspecting superficial siderosis of the central nervous system in clinical practice

Once the central nervous system surface is greatly encrusted with haemosiderin, even removing the source of bleeding will have little effect on the progression of clinical deterioration. Superficial siderosis of the central nervous system is rare and insidious, but magnetic resonance imaging has turned a previously late, mainly autoptical diagnosis into an easy, specific, in vivo, and possibly early one. Avoiding long diagnostic delay will be very important in those cases susceptible of causal treatment.

Molecular polarity in endothelial cells and tumor-induced angiogenesis

Endothelial cells expose receptors for vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) at the abluminal, basal surface that work as basic regulators of tumor-induced angiogenesis. Their specific localization makes them susceptible to the activity of tumor-released stimulatory factors, like VEGF/VPF, which induce proliferation of the endothelial cell toward the extracellular matrix. At the same time, VEGF/VPF stimulates endothelial cells to expose tissue factor (TF), the high-affinity transmembrane receptor and cofactor for cellular initiation of the plasma coagulation protease cascades through the extrinsic pathway, so generating thrombin. Thrombin exerts a number of activities: it forms an extracellular fibrin barrier from the VEGF/VPF-dependent fibrinogen extravasation; it activates progelatinase-A (pro-MMP-2), which destroys the basal membrane, allowing proliferation of endothelial cells (ECs) in the novel tumoral fibrin matrix; finally, it induces EC proliferation, potentiating the VEGF effect. Another important factor exposed at the abluminal endothelial cell surface is membrane type 1 matrix metalloproteinase (MT1-MMP), a membrane-bound metalloproteinase, which also activates progelatinase-A, allowing an alternative pathway to that of thrombin to destroy the basal membrane. In addition, we will see that MT1-MMP is also engaged in a direct, cell-associated fibrinolytic activity, essential for tubulogenesis of the novel outsprouting capillary.

A method for separation of heparin species from biological samples by ethanol precipitation of compounds solubilized in guanidine hydrochloride

In this paper we describe a procedure to determine glycosaminoglycan and oligosaccharide composition of biological samples such as cell cultures or tissue explants. We demonstrate that heparin species of different molecular mass can be easily fractionated by sequential ethanol precipitation in 4.0 M guanidine hydrochloride. We studied by gradient polyacrylamide gel electrophoresis fractionation of standard heparin and heparin-derived oligosaccharides by anion-exchange chromatography on DEAE-Sephacel resin eluted by increasing concentration of guanidine hydrochloride. The use of guanidine salts followed by sequential precipitation by increasing ethanol concentration allowed recovery of heparin and heparin-derived oligosaccharides.

Influence of static magnetic field on the antiproliferative effects of vitamin D on human breast cancer cells

We describe the effect of a 0.2 tesla (T) static magnetic field generated by a magnetic resonance tomograph and of vitamin D treatment on a human breast cancer cell line (MCF-7). Cell damage and proliferation were monitored by measuring the incorporation of [3H]thymidine in duplicating DNA and by the clonogenic assay. [3H]Thymidine incorporation in MCF-7 was stimulated by vitamin D at low doses (10(-12)-10(-10) M), whereas it was inhibited at higher concentrations (10(-9)-10(-6) M). Magnetic field treatment (0.2 T) decreased [3H]thymidine incorporation in human breast cancer cells, eliminating the proproliferative effect of low doses of vitamin D, and enhanced the vitamin D antiproliferative effect, further reducing [3H]thymidine incorporation, from -12.5% (P < 0.05) to -66.7% (P < 0.001), over the range of 10(-9) to 10(-6) M. In the clonogenic assay, ability of MCF-7 to form colonies was inhibited by vitamin D 10(-9) M and above, whereas 3-h exposure to 0.2 T magnetic field had no effect on the number of cell colonies formed. In conclusion, vitamin D treatment yields a permanent antiproliferative effect, while magnetic field exposure only temporarily slows down cellular growth. These findings suggest that therapy with vitamin D may prove beneficial for chemoprevention or treatment of breast cancer. Static magnetic field, alone or in combination, does not appear to represent an effective candidate for breast cancer therapy, at least at the intensity used in the present study.

Heparin binding peptides co-purify with glycosaminoglycans from human plasma

Glycosaminoglycans (GAGs) are complexed with plasma proteins and proteolysis of plasma reduced the protein-GAG ratio about 140-fold. After dialysis, analysis by gradient PAGE revealed heparinase-1-sensitive GAGs, thus suggesting that heparin could be among the plasma GAGs. However, after dialysis most of the plasma GAGs were still not 'free'. PAGE of peptides resistant to proteolysis showed high molecular weight bands on the two sides of the dialysis membrane despite the 3.5 kDa molecular weight cut-off. Progressive dilution of the sample allowed passage of peptides appearing as high molecular weight bands in the diffusate. We interpret this phenomenon as the presence of low molecular weight peptides that aggregate when concentrated. Peptides on both sides of the membranes bound heparin.

Bone mineral density and anthropometric measures in normal and osteoporotic men

In an ethnically homogeneous men population living in Tuscany, Italy, the relationship between age, height, body weight and bone mineral density were studied. In 50 men bone mineral density was measured by Dual Energy X ray Absorptiometry (DEXA). 13 subjects (26%) were osteoporotic. Age and bone mineral density were not related (R2 = 0.052). Bone mineral density was associated with body weight (R2 = 0.303), and height (R2 = 0.155). In osteoporotic men, mean (+/- SD) body weight was Kg. 65.8 +/- 11.2, lower than that recorded in non osteoporotic men, Kg. 77.3 +/- 10.2, (p = 0.0013). Age in osteoporotic and non-osteoporotic men did not differ (53.8 +/- 13.6 yrs and 60.9 +/- 11.8 yrs, respectively; p = 0.077). In conclusion, anthropometric factors, as predictors of bone disease, behave differently in women and men.

Effect of 0.2 T static magnetic field on human neurons: remodeling and inhibition of signal transduction without genome instability

We describe the effect of the static magnetic field generated by a 0.2 T magnetic resonance tomograph on a normal human neuronal cell culture (FNC-B4). After 15 min exposure cells showed dramatic changes of morphology: they formed vortexes of cells and exposed branched neurites featuring synaptic buttons. At the same time, thymidine incorporation and inositol lipid signaling were significantly reduced. Control (sham exposed) or non-neuronal cells (mouse leukemia, and human breast carcinoma cells) did not show any alteration following exposure. Endothelin-1 release from FNC-B4 cells was also dramatically reduced after 5 min exposure. However, PCR analysis of 12 DNA microsatellites selected as gauges of genome instability, did not reveal any alteration following exposure, thus ruling out a direct effect of the magnetic field on DNA stability. These data can be interpreted as a specific effect of the static magnetic field on human neuronal cells and are consistent with the induction of remodeling and differentiation; they demonstrate that fields below 0.5 T have significant biological effects on human neurons.

Association between vitamin D receptor gene polymorphism and nephrolithiasis

AIMS

To study the distribution of vitamin D receptor (VDR) gene alleles in hypercalciuric and nonhypercalciuric nephrolithiasis patients, hypothesizing that distinct biochemical parameters would be associated with different VDR genotypes.

METHODS

12 hypercalciuric, 15 normocalciuric nephrolithiasis patients, and 150 healthy subjects were recruited. The individual genetic pattern for VDR was evaluated by DNA extraction followed by polymerase chain reaction amplification of the VDR gene and digestion with the restriction enzyme BsmI.

RESULTS

In the hypercalciuric group, Bb patients represented 50% (6/12); bb patients 33% (4/12), and BB cases were 16% (2/12). The VDR frequency distribution was not statistically different in hypercalciuric patients and controls (Bb 72%; bb 16%; BB 12%). In the nonhypercalciuric group, the prevalence of the bb genotype (7/15; 47%) was thrice the percentage of control subjects, while the percentage of BB patients was similar to that of the control group (2/15; 13%). Patients with the bb haplotype exhibited a higher daily urinary calcium excretion. Among hypercalciuric patients, after a calcium-restricted diet, bb patients showed a 39% reduction in daily urinary calcium excretion in comparison with a nonsignificant 13% reduction observed in BB subjects (p = 0.004).

CONCLUSIONS

The effects of VDR gene polymorphism on calcium metabolism contribute to the understanding of the pathogenesis of urinary calculi.

Lack of association between body weight, bone mineral density and vitamin D receptor gene polymorphism in normal and osteoporotic women

In an ethnically homogeneous population of women living in Tuscany, Italy, the relationships between age, body weight, bone mineral density and the vitamin D receptor (VDR) gene polymorphism were studied, with the objective of recognizing patients at risk for osteoporosis. In 275 women bone mineral density was measured by Dual Energy X-rays Absorptiometry (DEXA). In 50 of them the individual genetic pattern for VDR was evaluated by DNA extraction followed by PCR amplification of the VDR gene, and digestion with the restriction enzyme BsmI. Age and bone mineral density were inversely related (R2 = 0.298). Body weight was associated with bone mineral density (R2 = 0.059), but not with age. In osteoporotic women, mean (+/- SD) body weight was 59.9 +/- 6.5 Kg, lower than that recorded in non osteoporotic women (64.2 +/- 9.4 Kg), even though not significantly different (p = 0.18). No association was found between VDR gene polymorphism, bone density or body weight. The performance of anthropometric and genetic components appear to be poor, and, at least for the time being, bone mineral density measurement by means of MOC-DEXA represents the optimal method to detect women at risk for postmenopausal osteoporosis.

Distribution and characteristics of synoviocytes in the rabbit knee joint: a scanning/transmission electron microscopic study

The distribution and the characteristics of A and B synoviocytes were investigated using scanning and transmission electron microscopy in the study of the three types of synovial membranes (fibrous, areolar, adipose) of the rabbit knee joint. The scanning electron microscope showed that the B-synoviocytes had dendritic processes and were separated by wide spaces in the fibrous synovium. The areolar synovium was covered by numerous B-synoviocytes of fibroblastoid-shape. The B-synoviocytes of the adipose synovium were characterized by short cytoplasmic processes. The transmission electron microscope revealed that the B-cells showed signs of intense synthetic activity such as the presence of an evident rough endoplasmic reticulum, the Golgi apparatus and many peripheric vesicles. Our study also revealed that cells with morphological and ultrastructural characteristics of macrophages, the so-called A-synoviocytes, were present in the areolar membrane. We concluded that B-synoviocytes can show variable shape under normal conditions: in particular, dendritic morphology seems to be a normal characteristic of the synoviocytes of the fibrous membrane. Moreover, our results demonstrate that A and B synoviocytes are ultrastructurally and morphologically distinct cells and that each type has different functions.

Cardiac magnetic resonance imaging: technique and anatomy

Recent advances achieved in Magnetic Resonance Imaging equipment and procedures allow a thorough study of the heart, yielding anatomic, functional and angiographic information. Spin-echo sequences are specific for heart morphology while gradient-echo sequences are fundamental to the functional study. Fast sequences reduce the examination times with the possibility of single breath-hold images. Coronary arteries can be directly visualized and cardiac perfusion can be assessed. Velocity encoded images allow flow quantification and with myocardial tagging, cardiac mechanics is accurately defined.

Vitamin D receptor gene polymorphism is associated with metastatic breast cancer

The vitamin D receptor (VDR) has been detected in breast tumor cells. We tested the hypothesis that VDR gene polymorphism might influence the outcome of women affected by breast cancer. A total of 88 breast cancer patients were recruited: 50 women were affected by newly diagnosed breast cancer whereas 38 women suffered from relapsing disease. The individual genetic pattern for VDR was evaluated by DNA extraction followed by PCR amplification of the VDR gene, and digestion with the restriction enzyme BsmI. In 167 healthy women, participating in the osteoporosis prevention trial and being used as a control, we detected 121 Bb heterozygotes (72%), 26 homozygotes for the bb alleles (16%), and 20 homozygotes for the BB alleles (12%). In the newly diagnosed breast cancer group the occurrence of Bb patients was 58% (29/50); bb patients represented 22% (11/50), and BB cases were 20% (10/50). The VDR frequency distribution in the control and primary disease patient groups was not statistically different. In the metastatic cancer group, the prevalence of the bb genotype (14/38; 37%) was double the percentage of control subjects, whereas the percentage of BB women with metastases was half the control group (2/38; 5%). Women who were homozygous bb appeared to have almost a four times higher risk of developing metastases than BB women. Whatever the molecular mechanisms underlying the VDR effects in cancer cells, we believe that the VDR gene polymorphism may represent an important determinant in the evaluation of women affected by breast cancer and might help design targeted therapy.

The old and the new in p53 functional regulation

The gene termed p53 is one of the most extensively studied for the past 18 years and the amount of literature published on this gene reflects its relevance in the field of molecular oncology; thus, loss or mutation of this oncosuppressor gene is probably the molecular lesion most frequently observed in human tumors. The aim of this minireview is to report, discuss, and interpret some recent observations on this topic: (I) The relationship with the Ataxia-Telangectasia gene and with the signaling enzyme phosphatidylinositol 3-kinase (PI3K). (II) The relationship between DNA damage, p53, and sensitivity to anticancer therapies. (III) The gain of function caused by mutations that transform the oncosuppressor p53 gene into a dominant transforming oncogene and (IV) The phosphorylative regulation of p53 and its relationship with the mitogenic signaling cascade involving protein kinase C and tumor promoters.

Cellular proliferation and second messenger formation altered by dialysis membranes

BACKGROUND

In this study we investigated the effect of different dialysis membranes on the clonal murine haematopoietic cell line 32D cells transmembrane signalling machinary, monitored by 1,2-diacylglycerol (DAG) formation, and on their ability to respond to the physiological growth factor interleukin-3 (IL-3).

METHODS

Cells were exposed to dialysers (cuprophane, CU; polysulphone, PS; cellulose diacetate, CA; polyacrylonitrile, AN69; polymethylmethacrylate, PMMA; cellulose triacetate, CT; polyamide, PA; and polycarbonate, PC); they were collected, counted, and treated with physiological amount of IL-3. Cell proliferation was monitored as incorporation of radioactivity in duplicating DNA. DAG was measured by thin-layer chromatography in cell labelled with tritiated glycerol overnight.

RESULTS

CU and PA stimulated cell proliferation in comparison with resting cells. PS and TC did not significantly affect thymidine incorporation either in IL-3-stimulated, or in resting cells. Cells exposed to AN69, PC, and CA showed depressed basal incorporation of thymidine (70, 54 and 56% of controls respectively) but retained the ability to respond to IL-3 in a manner not statistically different from controls. PMMA reduced thymidine incorporation both in basal condition and after IL-3 stimulation CU and PC activated early cell signalling (1.95 x and 1.31 x respectively, DAG increase over control), while PA and TC depressed DAG generation (0.38 x and 0.47 x respectively, DAG increase over control). PS, CA, AN69, and PMMA did not stimulate DAG generation.

CONCLUSIONS

Alternations of intracellular mitogenic signalling appear to correlate with the ability to make a cell competent for function. These results might help to elucidate the effect of different dialysers, at the molecular level, on the blood cell behaviour in vivo.

[The determination of BB genotype of vitamin D receptors identifies patients at risk for osteoporosis]

The gene responsible for peak bone mass has been recently identified as the gene coding for the Vitamin D Receptor (VDR); there exist two alleles, termed "B" and "b", determining a typical allelic polymorphism. We determined the VDR genotype of 50 young post-menopausal women (mean age: 56 years), and measured bone density by Dual Energy X ray Absorptiometry (DEXA) twice: at the beginning of the study and after one year. VDR genotype was determined using the DNA extracted from hair cells, thus avoiding the use of blood samples. The frequency of VDR genotypes (BB or bb homozygous; Bb heterozygous) was approximately the same in the two groups of subjects (i.e., normal controls and osteoporotic women). The bone density of normal subjects (36) was measured for the second time one year after the first measurement. All BB homozygous subjects showed significantly decreased bone density values; 50% of them showed values below 0.750 g/cm2 at the second measurement, thus being classified as osteoporotic. However, neither bb homozygous nor Bb heterozygous subjects showed any significant decrease in bone density values (about 4% of the initial value). Therefore, determining the VDR genotype was critical for identifying the subjects who were normal at the first measurement, but had markedly decreased bone density values later, thus being at risk of developing osteoporosis.

Intracellular diacylglycerol: a mitogenic second messenger proposable as marker of transformation in squamous cell carcinoma of the lung

In this study, we examined 50 patients with documented lung cancer projecting in the bronchial lumen unilaterally. Bronchial lavage from the affected and unaffected sides provided neoplastic and normal cells in which we studied an intracellular mitogenic second messenger, diacylglycerol, associated with transformation. The levels of diacylglycerol in cells from the affected side were compared with that from the healthy side, thus providing an internal control for each patient. Our data show that the levels of diacylglycerol in lavage fluid relative to affected bronchus are elevated in 56% of all the patients examined. This elevation reaches 77% in patients with squamous cell carcinoma, a value of sensitivity higher than 'traditional' markers for cancer of the lung. Thus, these findings may have significant implications for the use of diacylglycerol measurement as a novel biomarker for early detection of lung cancer, and for monitoring recurrences after treatment.

In vitro effects of some differentiation inductors in metaplastic epithelium of the human nasal cavity

The alterations in the mucociliary unit in the course of chronic inflammation of the upper respiratory tract correspond to morphologic anomalies of the respiratory epithelium and induce cuboidal and squamous metaplasia. While the squamous pattern is most probably irreversible, it is still not clear whether it is possible to restore ciliogenesis in cuboidal metaplasia. In the present study, the action of different inductors of differentiation was evaluated in vitro in isolated cells and explants from human nasal metaplastic epithelium. Polar/apolar compounds induced secretory activity, whereas retinoic acid was able to induce ciliogenesis in some cases. Therefore, the cuboidal metaplastic condition appears to be reversible, and two distinct pathways of differentiation, secretory and ciliogenetic, are identifiable.

Role of three cancer "master genes" p53, bcl2 and c-myc on the apoptotic process

We review some of the most recent developments concerning three genes involved in human cancer: p53, bcl2 and c-myc. Recent data have demonstrated that the bcl2 gene protects tumor cells from apoptosis induced by a variety of agents, including ionizing radiation, and is thus related to resistance to DNA-damaging therapeutic agents. The p53 tumor suppressor gene, however, has been related with growth arrest, apoptosis and thus with selective sensitivity to the killing effects of ionizing radiation and DNA-damaging drugs. This functional antagonism between the two genes was recently substantiated in molecular terms by demonstration of reciprocal down-regulation due to the presence of a p53-dependent transcription silencer in the untranslated region of the bcl2 gene. Growth arrest in the G1 phase of the cell cycle and induction of apoptosis are two distinct and dissectable functions of p53: bcl2 is able to antagonize the induction of apoptosis by p53, but not the growth arrest in G1. However, coexpression of bcl2 and of the oncogene c-myc efficiently antagonizes effects of p53 on G1 arrest and apoptosis, thus suggesting a cooperation between the two oncogenes. In addition, c-myc disrupts other functions of genetic control in the early G1 phase of the cell cycle including the expression of D1 cyclin. We believe that knowledge of the functional/molecular interactions between these three genes involved in human cancer is a fundamental prerequisite to improve the knowledge on prognosis and to design innovative therapeutic approaches.

Conferring drug resistance by MDR1 gene transfection increases susceptibility to irradiation and lipid peroxidation in 3T3 cell line

This study was performed to test the hypothesis that conferring multiple drug resistance reduces cell susceptibility to irradiation and iron-stimulated lipid peroxidation. Multidrug resistant (PN1A) and parental drug sensitive (PSI-2) cell lines were exposed to ADP-Fe or Ascorbate-Fe complexes at 37 degrees C and to irradiation. Lipid peroxidation was estimated by the TBA test, whereas x-ray effect was estimated by clonogenic assay. Cell glutathione-S-transferase (GST), total and Se-dependent glutathione peroxidase (GSH-Px) activities, and glutathione and vitamin E were measured. PN1A produced more peroxides than PSI-2 after exposure to iron complexes and formed fewer colonies after irradiation. Higher activities of GST and total and Se-GSH-Px were observed in PN1A. Vitamin E and total glutathione did not differ in the two cell subclones. These data show that the induction of the mdr1 phenotype by transfection of mdr1 gene in 3T3 cells increases susceptibility to irradiation and iron stimulated lipid peroxidation.

Study of second messenger levels and of sugar catabolism enzyme activities in transformed cells resistant to ionizing radiations

We measured the level of second messengers, the activity of carbohydrate metabolism enzymes, and the resistance to ionizing radiations in normal 32D hematopoietic cells, in v-erbB transformants and in spontaneous transformants. v-erbB and spontaneous transformants were resistant to radiations as compared with their normal counterpart. The second messenger diacylglycerol was elevated in radioresistant clones. Only v-erbB transformants showed increase of the activities of enolase and glucose-6-phosphate dehydrogenase. v-erbB-transformed NIH/3T3 cells, selected as control, showed identical correlation between radioresistance, increase of diacylglycerol, and of enolase and glucose-6-phosphate dehydrogenase activity. These results indicate that increase of diacylglycerol is correlated with resistance to the killing effect of ionizing radiations and could be proposed as a marker of radioresponse.

Second messenger formation altered by different dialysis membranes in human leukocytes

A number of agents stimulate transmembrane cell-signaling in different cell types through the formation of the second messenger diacylglycerol (DAG) which activates protein kinase C (PKC). The aim of this study was to investigate phospholipase C activation, DAG formation, and cellular adhesion to dialysis membranes after simulated dialytic treatment of either human leukocytes or clonal hematopoietic cells. Cells were circulated for 60 minutes in a closed-loop dialysis system using three different dialyzers: cuprophan (CU), polysulphone (PS), and AN69 (PAN). Another cell aliquot was left within the dialyzers without circulation. Samples were taken at different time intervals and cells counted. Cells were labeled with tritiated glycerol overnight, and DAG was measured by thin-layer chromatography. Our data showed that cells tended to adhere with more efficiency to CU than to the synthetic dialyzers. Circulation in the in vitro dialysis circuit resulted in the rapid (5 min) formation of [3H]DAG (CU 1.95-; PS 1.34-; PAN 1.24-fold increase over untreated cells). The DAG level peaked at 15 to 30 minutes and remained constant thereafter (CU 1.70; PS 1.96; PAN 1.66). When we measured DAG formation in cells that had been kept in the dialyzers without circulation, we found that cells exposed to CU showed a much higher and rapid activation than those exposed to PS or PAN, as if CU per se was able to activate early cell signaling (CU 1.95-; PS 0.97-; PAN 1.09-; DAG, -fold increase over control).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of phosphotyrosine phosphatase over-expression on glutathione metabolism in normal and oncogene-transformed cells

We measured the level of reduced glutathione (GSH) and oxidized glutathione (GSSG) in normal and oncogene-transformed NIH/3T3 fibroblasts and 32D hematopoietic cells. NIH/3T3 cells transformed by the activated oncogenes erbB, src, and raf, showed increased levels of GSH with concomitant alterations in the levels of GSH-related enzymes. Transfection and over-expression of a synthetic gene coding for a phosphotyrosine protein phosphatase (PTPase), which inhibited the proliferation of normal and transformed NIH/3T3 cells, was accompanied by a decrease in GSH levels in normal and erbB-transformed fibroblasts, and by an increase in src and raf transformants. Among GSH-related enzymes, only gamma-glutamylcysteine synthetase was altered in normal and erbB-transformed NIH/3T3 fibroblasts following PTPase transfection. Therefore, tyrosine phosphorylation could be selectively involved in the regulation of GSH metabolism in normal and oncogene-transformed NIH/3T3 fibroblasts, possibly by a dual-type effect on receptor/oncoprotein-mediated mitogenic signal transduction. However, no relationship was observed between the GSH and PTPase effect on cell growth, either after oncogene transfection or PTPase transfection. Moreover, the changes in GSH metabolism were specifically related to cell lineage. In fact GSH and related enzymes did not change in 32D hematopoietic cells transformed by the same activated erbB oncogene and in those--normal or transformed--over-expressing the PTPase: in these cells also, over-expression of the PTPase gene was not accompanied by growth inhibition.

Correction of neutropenia with rHuG-CSF after loss of response to rHuGM-CSF following autologous bone marrow transplant

We describe a patient who presented with graft failure following autologous BMT, with an initial response of the neutrophil count to rHuGM-CSF but eventual loss of this response. Subsequently, this patient responded to rHuG-CSF. This could be explained by the fact that rHuG-CSF stimulates both early and late myeloid progenitor cells whereas rHuGM-CSF stimulates mainly the intermediate myeloid progenitor cells. This finding suggests that rHuG-CSF should be investigated for the treatment of patients with graft failure following ABMT.

Antiproliferative effects of heparin on normal and transformed NIH/3T3 fibroblasts

We studied the effect of heparin on proliferation and signalling in normal NIH/3T3 fibroblasts, and in cells transformed by different oncogenes. Heparin inhibited the proliferation of normal as well as of v-sis and v-erbB transformed fibroblasts in the presence of serum, but failed to inhibit v-erbB-driven proliferation in serum-starved cultures; under these conditions, heparin inhibited by approximately 50% the proliferation of normal and v-sis- transformed cells. Heparin also inhibited PDGF-induced cell proliferation and inositol lipid turnover in v-sis transformants, but it did not affect PDGF mitogenic signalling in NIH/3T3 fibroblasts.

Negative growth control by a novel low M(r) phosphotyrosine protein phosphatase in normal and transformed cells

Having determined the complete amino acid sequence of a cytosolic phosphatase purified from bovine liver, we studied the role of this enzyme (referred to as 'PTPase') in the control of cell proliferation. We used NIH/3T3 fibroblasts, both normal and transformed by the oncogenes v-erbB, v-src, and v-raf: a synthetic gene coding for PTPase was transfected into, and overexpressed in, normal and transformed NIH/3T3 cells with resulting inhibition of cell growth. Inhibition of proliferation correlated with the level of foreign PTPase; growth in soft agar was also inhibited in transformants overexpressing the enzyme. However, PTPase overexpression did not inhibit the rapid turnover of inositol lipids stimulated by platelet-derived growth factor. We conclude that this novel PTPase is active on cell type-specific signalling substrates that control normal and transformed fibroblast proliferation.

Defective signal transduction in platelets from cirrhotics is associated with increased cyclic nucleotides

BACKGROUND

Patients with advanced cirrhosis show defective platelet aggregation, which is dependent, at least in part, on intrinsic platelet abnormalities. The aim of this study was to evaluate the activating and inhibitory pathways of platelet signal transduction in cirrhotic patients.

METHODS

Twelve cirrhotic patients and 12 control subjects participated in this study. Measurements were performed on washed platelets.

RESULTS

Thrombin-stimulated inositol 1,4,5-trisphosphate production was reduced fivefold, and the increase in cytosolic calcium concentration was significantly lower in platelets from cirrhotic patients following stimulation with thrombin, platelet activating factor, or U-46619. In addition, the activity of the platelet Na+/H+ antiporter, evaluated after an acid load, was significantly lower in platelets from cirrhotic patients (0.90 +/- 0.19 vs. 1.37 +/- 0.16 delta pHi/min, P = 0.07). Cirrhotic patients also showed a significantly increased basal intraplatelet content of both 5'-cyclic adenosine monophosphate (cAMP) (2724 +/- 330 vs. 1561 +/- 258 fmol/10(8) platelets, P < 0.05) and 5'-cyclic guanosine monophosphate (cGMP) (217 +/- 18 vs. 159 +/- 29 fmol/10(8) platelets, P < 0.05).

CONCLUSIONS

Our results indicate that in platelets from cirrhotic patients, defective early signal transduction is associated with an increase in platelet cAMP and cGMP, thus revealing new mechanisms contributing to the defective platelet function in this disease.

Altered metabolism of glutathione in cells transformed by oncogenes which cause resistance to ionizing radiations

We measured glutathione (GSH) metabolism in normal NIH/3T3 fibroblasts, and in cells transformed by the oncogenes sis, erbB, src, ras, dbl, and raf.erbB,src,ras and raf, but not sis and dbl transformants, showed increased level of total and reduced GSH as compared with normal NIH/3T3 fibroblasts; oxidized GSH was elevated only in src- and ras-transformed cells. Increased total GSH content was associated with decreased activity of the synthetic enzyme gamma-glutamylcysteine synthetase, and oxidized GSH level with increased activity of GSH reductase. These data suggest that GSH synthesis was selectively enhanced in cells transformed by specific oncogenes, with resulting down-regulation of its synthetic enzyme; alterations of GSH metabolism appeared to be peculiar of transformation by specific oncogenes, and not trivial epiphenomena of neoplastic transformation. Oncogenic transformants that presented elevated level of GSH were also those reported to be resistant to antineoplastic drugs and ionizing radiations, thus confirming a possible link between altered GSH metabolism and resistance to antineoplastic treatment.

Urokinase-urokinase receptor interaction: non-mitogenic signal transduction in human epidermal cells

We studied non-mitogenic signal transduction in a human cell line of epidermal origin which is induced to chemotaxis following stimulation with human urokinase-type plasminogen activator (u-PA) or with the amino-terminal fragment (ATF) of u-PA A chain, which specifically interacts with the cellular receptor. U-PA and ATF stimulated the formation of diacylglycerol (DAG) independently of inositol lipid and phosphatidylcholine turnover, but concomitantly with de novo synthesis from glucose, thus resembling the DAG neosynthesis activated by insulin. DAG was measured in normal epidermal cells and in cells transfected with the human u-PA receptor (u-PAR) gene and stimulated with u-PA or ATF. Transfected clones showed an increase of cell motility under an ATF gradient in vitro as well as an increase of DAG production. These findings identify a novel mechanism of second messenger formation that conveys chemotactic signals upon stimulation of the u-PAR.

Overexpression of a synthetic phosphotyrosine protein phosphatase gene inhibits normal and transformed cell growth

We studied the level of the cytosolic phosphotyrosine protein phosphatase (PTPase) (originally termed low-M(r) acid phosphatase) in normal NIH/3T3 and in v-erbB-transformed fibroblasts. The level of the enzyme, assayed by ELISA, was inversely related to cell proliferation, normally growing cells had less enzyme than their contact-inhibited counterparts and v-erbB transformants had less enzyme than normal NIH/3T3. In order to overexpress the enzyme and study its effects in normal and transformed cells, we transfected a synthetic gene coding for the PTPase in control NIH/3T3 and v-erbB transformants. The overexpressed enzyme was recognized by antibodies raised against the native enzyme and, in cells overexpressing the PTPase, we observed a marked dephosphorylation of tyrosyl residues of cellular proteins. Cell proliferation, in both normal and v-erbB transformants overexpressing the PTPase, was measured. We observed that PTPase overexpression was accompanied by significantly reduced thymidine incorporation in both cell types, either serum-starved or serum-stimulated. The ability of transformed v-erbB cells to grow in soft agar was also markedly decreased by overexpression of the enzyme. Taken together, our results indicate that overexpression of PTPase might interfere with mitogenic signalling pathways in both normal and transformed cells, and propose a role for PTPase in the control of cell proliferation.

Mitogenic signal transduction: a common target for oncogenes that induce resistance to ionizing radiations

We hypothesized that resistance to ionizing radiations accompanying neoplastic transformation caused by some oncogenes was due to common biochemical pathways affecting the mechanism of mitogenic signal transduction. In order to verify this hypothesis, we studied the formation of mitogenic second messengers in cells transformed by oncogenes that induce radioresistance. We observed an increase of diacylglycerol which activates protein kinase C, an increase of phosphatidylcholine metabolism, with a concomitant decrease of inositol lipid metabolism. Our data show that sensitivity to ionizing radiations was inversely related to the intracellular level of diacylglycerol; study of signalling alterations in spontaneous tumors could provide predictive indications about the responsiveness of neoplasia to radiation therapy.

Marrow transplantation from human leukocyte antigen-identical or haploidentical donors for correction of Wiskott-Aldrich syndrome

Since 1979, a total of 17 patients with Wiskott-Aldrich syndrome have undergone allogeneic bone marrow transplantation at Memorial Sloan-Kettering Cancer Center. Eleven patients received marrow from either human leukocyte antigen (HLA) genotypically identical siblings (nine patients) or an HLA phenotypically identical parent (two patients). Six patients received marrow grafts from HLA-disparate parents. Cytoreduction was accomplished with busulfan and cyclophosphamide for the HLA-identical recipients and total-body irradiation followed by high-dose cytarabine therapy in the mismatched recipients. All 11 recipients of HLA-identical marrow had successful grafts, and 10 of 11 are alive and well 28 to 145 months after transplantation. One patient died 10 months after transplantation of chronic graft-versus-host disease and interstitial pneumonitis caused by cytomegalovirus. Only one of the six mismatched graft recipients survives, 52+ months after transplantation; the other patients have died of extensive chronic graft-versus-host disease (one patient), lymphoma (three patients), or progressive pancytopenia accompanying Candida sepsis (one patient). Thus bone marrow transplantation represents the treatment of choice in patients with Wiskott-Aldrich syndrome who have an HLA-identical donor. However, our approach for patients lacking a histocompatible family donor requires modifications to overcome allogeneic resistance and decrease the posttransplantation immunoincompetence in these patients.

Mitogenic signal transduction in normal and transformed 32D hematopoietic cells

We studied mitogenic signal transduction in normal and oncogene-transformed 32D cells, a murine hematopoietic cell line that is normally dependent on interleukin-3 (IL3) for proliferation and survival. The formation of second messengers was measured in normal cells stimulated with IL3, and in cells transfected with foreign growth factor receptor genes and stimulated with appropriate growth factors. We also measured the steady-state level of second messengers in 32D cells transformed by erbB, abl, and src oncogenes which abrogate growth factor requirement. We found that IL3 stimulated the formation of diacylglycerol independently of inositol lipid turnover, but concomitantly with increased turnover of phosphatidylcholine. Epidermal growth factor (EGF), and platelet-derived growth factor (PDGF) stimulated the 'classical' turnover of inositol lipids with formation of diacylglycerol and calcium-mobilizing inositol phosphates. Colony stimulating factor-1 triggered inositol lipid turnover, although to a much lower extent than EGF and PDGF. Transformed cells showed elevated levels of diacylglycerol together with increased turnover of phosphoinositides and phosphatidylcholine. Taken together these results indicate that different growth factors and oncoproteins associate with multiple signalling pathways in 32D cells.

Tyrosine mutations within the alpha platelet-derived growth factor receptor kinase insert domain abrogate receptor-associated phosphatidylinositol-3 kinase activity without affecting mitogenic or chemotactic signal transduction

A phosphatidylinositol-3 (PI-3) kinase activity of unknown biological function associates with tyrosine kinase-containing proteins, including a number of growth factor receptors after ligand stimulation. In the beta platelet-derived growth factor (beta PDGF) receptor, phosphorylation of a specific tyrosine residue within the kinase insert domain was required for its interaction with this enzyme. We show that substitutions of phenylalanine for tyrosine residue 731 or 742 within the kinase insert domain of the alpha PDGF receptor do not impair PDGF-induced tyrosine phosphorylation of the receptor or of an in vivo substrate, phospholipase C-gamma. Moreover, phosphatidylinositol turnover in response to ligand stimulation is unaffected. However, both lesions markedly impair receptor association with PI-3 kinase. Antiphosphotyrosine antibody-recoverable PI-3 kinase was also dramatically reduced in PDGF-stimulated cells expressing either mutant receptor. Since neither mutation abolished PDGF-induced mitogenesis or chemotaxis, we conclude that alpha PDGF receptor-associated PI-3 kinase activity is not required for either of these major PDGF signalling functions.