Activation of the IGF-IR system contributes to malignant growth of human and mouse medulloblastomas

Insulin-like growth factor I receptor (IGF-IR) has been implicated in the normal and malignant growth of many cell types including cells from the central nervous system. In the cerebellar cortex IGF-IR mRNA is found in granular cells and IGF-I stimulation is mitogenic and protects cells from low-potassium-induced apoptosis. Since primitive neuroectodermal tumors/medulloblastomas (PNETs/medulloblastomas) are suspected to originate from the external cerebellar granular layer, it is reasonable to postulate that IGF-IR and/or its signaling molecules may contribute to the transformation of these poorly differentiated cells. To study activation of the IGF-IR system in medulloblastomas, we have utilized an antibody (anti-pY1316) that specifically recognizes the phosphorylated (active) form of the IGF-IR. Medulloblastoma biopsy specimens were positive when examined immunohistochemically with anti-Y1316 antibody. Further analysis of the IGF-IR system was performed in three human (Daoy, TE-671, D283 Med) and four mouse (BsB8, BsB13, Bs-1b, Bs-1c) medulloblastoma cell lines. All the murine cell lines examined express IGF-IR and PI3-kinase at relatively normal levels, and grossly overexpress IRS-1, when compared with normal mouse cerebellum. Within 15 min following IGF-I stimulation both mouse and human cell lines phosphorylate the beta subunit of the IGF-IR, IRS-1, Akt, and MAP kinases. They respond with cell proliferation when stimulated solely with IGF-I and are strongly inhibited when challenged with a dominant negative mutant of the IGF-IR (486/STOP), or with antisense oligonucleotides against the IGF-IR mRNA.

Surgery of rheumatic mitral stenosis: comparison of different techniques

OBJECTIVE

The breakthrough of percutaneous transvenous mitral commissurotomy (PTMC) has dramatically changed the indications for the surgical treatment of rheumatic mitral stenosis over the last decade. No recent studies comparing long-term results of PTMC, open mitral commissurotomy (OMC) and mitral valve replacement (MVR) with bileaflet prostheses are available in medical literature.

METHODS AND RESULTS

Between January 1991 and December 1997, 313 patients with pure and isolated rheumatic stenosis were treated in our department. One hundred and eleven patients underwent PTMC, 82 OMC and 120 MVR. There was no statistical difference (p>0.05) between the mortality rates of the three groups of patients. No cases of hospital mortality were observed in the patients who underwent PTMC and OMC, whereas two patients (1.6%) died within 30 days after MVR. Seven year actuarial survival results are: 95.41+/-2(SE)% (PTMC), 98.05+/-1% (OMC) and 92.82+/-33% (MVR) (p=NS). Freedom from embolism was 98.78+/-1% in PTMC, 98.78+/-1% in OMC and 92.52+/-2% in MVR (p>0.05); freedom from reoperation was 88.43+/-8% in PTMC, 96.35%+/-2% in OMC and 97.72+/-1% in MVR (p>0.05). The mean NYHA class at the end of follow-up was lower in OMC (1.14+/-0.3) versus PTMC (1.39+/-0.6) and MVR (1.41+/-0.71) (p=0.001).

CONCLUSIONS

Even though conservative techniques are the first option to consider in treating mitral valve stenosis, valve replacement with bileaflet prostheses no longer represents a limiting factor to survival and quality of life.

Associated vascular lesions in patients undergoing coronary artery bypass grafting

Atherosclerotic involvement of extracoronary arteries in patients undergoing myocardial revascularization can cause severe postoperative complications and increase postoperative mortality. Between January and November 1998, routine preoperative echo-Doppler study of carotid vessels, abdominal aorta and iliac-femoral arteries was performed in all patients undergoing coronary artery bypass grafting (CABG) at our institution, in order to assess the prevalence and the degree of associated vascular lesions. Correlations between echo-Doppler findings, angiographic patterns of coronary lesions and atherosclerotic risk factors were analyzed in all cases. Among 302 patients undergoing CABG, 186 (61.6%) had carotid disease, with a haemodynamically significant stenosis (>70%) of internal carotid in 31 (10.2%). Twenty-three patients had asymptomatic severe carotid disease. A significant correlation between severity of coronary disease and prevalence of severe carotid disease was found (p = 0.02). An abdominal aortic dilatation (diameter > 25 mm) was found in 20 cases (6.6%), with a diameter >35 mm in 7 patients (2.3%), 6 with triple-vessel coronary disease, and 1 with double-vessel disease. Atherosclerotic lesions of iliac-femoro-popliteal axis were found in 165 (54.6%) patients, with a strong correlation to the severity of coronary disease (p = 0.02); lesions were haemodynamically significant (> 70%) in 48 (15.8%) cases. Symptoms of carotid and peripheral vascular disease are no reliable predictors of perioperative risk in patients undergoing CABG. Non-invasive complete arterial investigation should be routinely performed in these patients, in order to plan the most suitable operative approach and to prevent perioperative vascular complications.

Efficient in vitro and in vivo gene regulation of a retrovirally delivered pro-apoptotic factor under the control of the Drosophila HSP70 promoter

We have developed a self-inactivating retroviral vector system with an internal, inducible Drosophila HSP70 promoter. This vector system delivers the desired transgene into cells rapidly and efficiently. It generates mixed populations of transduced cells where the transgene is inducible, and does not require the isolation of specific clones. Since the transgene is not expressed (or poorly expressed) at the restrictive condition (34 degrees C), mixed populations can be selected in which tumor suppressors or other inhibitory genes can be strongly induced upon changing the conditions (39 degrees C or the plant amino acid L-canavanine). This retroviral vector should be very useful for the expression of sequences that are poorly tolerated by cells, and is also active in animals.

Evaluation of epidermal growth factor receptor, carcinoembryonic antigen and Lewis carbohydrate antigens in human colorectal and liver neoplasias

The expression of LewisY related carbohydrate antigens and the content of epidermal growth factor receptor (EGF-R), the carcinoembryonic antigen (CEA) and the alpha-fetoprotein (AFP) in colorectal and liver tumors were determined. These included 30 large bowel adenocarcinomas (7 colon, 6 sigma, 5 caecum, 12 rectum), 12 hepatocellular carcinomas and 6 liver metastases. Histologically normal tissue excised along with the tumors were used as controls. All plasma membranes studied showed specific EGF binding, and tumor plasma membranes had an EGF receptor level higher than that of the normal counterpart. However, EGF-R was positive in only a few tumors, and no correlation between clinical stages and grades of differentiation was observed. Cytosol CEA was higher in tumors than in normal counterparts. Tissue AFP and CEA content was different in liver hepatocellular carcinomas and in liver metastases. They are good markers to differentiate between primary and secondary liver neoplasias. The LewisY and related carbohydrate antigens, evaluated by the reactivity of the tissues to monoclonal antibody MAb B3, are expressed in liver metastases from colorectal adenocarcinoma. MAb B3 failed to react with hepatocellular carcinomas and with peritumoral liver tissues obtained from both metastatic and primary tumor lesions. These data suggest that immunoblotting with MAb B3 may be useful to obtain more information on liver carcinomas. Furthermore, MAb B3 or CEA armed with toxin in the form of recombinant immunotoxin or linked to a radionuclide can be useful in new treatments of metastatic lesions, such as immunotherapy, radioimmunotherapy and radioimmunoguided surgery.

[Prevalence of vascular disease in candidates for myocardial revascularization with aortocoronary bypass: review of the literature and practical implications]

BACKGROUND

Cardiovascular disease remains the main cause of death and morbidity in the industrialized world. Atherosclerosis is a slowly progressive disease; coronary artery disease may be the first presentation of a systemic pathology. The association between coronary artery disease and peripheral vascular disease has often been confirmed by multicenter trials; nevertheless it still remains a subject of debate.

METHODS

In order to assess the incidence of coronary artery disease and the degree of associated vascular lesions, between January 1997 and September 1999, in the Department of Cardiothoracic Surgery of the Second University of Naples (Italy), all candidates to coronary artery bypass grafting (CABG) were submitted to routine preoperative echo color Doppler study of the carotid vessels, abdominal aorta and iliac-femoral arteries. The correlation between the echo color Doppler findings, the angiographic patterns of coronary lesions and atherosclerotic risk factors was analyzed in all cases.

RESULTS

Among 540 patients undergoing CABG, 418 (77.4%) had carotid disease, with a stenosis > 70% in 62 (11.3%). Forty-nine (79%) patients had asymptomatic severe carotid disease. A significant correlation between the severity of coronary disease and the incidence of severe carotid disease was found (p = 0.02). An abdominal aortic dilation was found in 37 cases (6.7%). Its diameter exceeded 35 mm in 14 patients (2.5%) and in 8 it was associated with triple vessel coronary disease. Atherosclerotic lesions of the iliac-femoro-popliteal axis were found in 394 (72.9%) patients and strongly correlated with the severity of coronary artery disease (p = 0.02); lesions were hemodynamically significant in 91 (16.8%) cases.

CONCLUSIONS

Our study emphasizes the association between coronary artery disease and vascular disease. Non-invasive complete arterial investigation should be routinely performed in patients undergoing CABG.

Effect of endothelin 1 on proximal reabsorption and tubuloglomerular feedback

Endothelin 1 (ET-1) is a powerful constrictor of the afferent glomerular artery, implicated in the occurrence of both functional and acute renal failure. Besides being produced by the endothelium, ET-1 is also secreted by proximal tubular cells, suggesting that it may act as an endoluminal messenger. The present study is intended to verify whether ET-1 may play a role in the tubuloglomerular feedback system. The experiments were performed in rat superficial glomeruli. In 25 nephrons we measured by the total collection technique the single-nephron glomerular filtration rate (SNGFR; nl/min) and reabsorption rates before (control) and during microinjection (MIJ) of ET-1 10(-7) M into the first proximal convolution or Bowman's space. The SNGFR rose from 27+/-3 to 61+/-11 nl/min (p<0.01), the percent proximal reabsorption rose from 43 to 74%, and the absolute reabsorption rose from 13+/-2 to 46+/-11 nl/min (p<0.01). In additional 23 nephrons the collections were performed at the earliest distal convolution accessible on the renal surface, while MIJ was performed in the last proximal convolution of the same nephrons. The SNGFR rose during MIJ from 22+/-3 to 40+/-6 nl/min (p<0.01), the percent reabsorption rose from 61 to 66% (p>0. 77), and the absolute reabsorption rose from 12+/-2 to 26+/-4 nl/min, (p<0.003). Exposure of the macula densa to intraluminally injected ET-1 causes an abrupt increase in SNGFR of the experimental nephron, in the absence of changes in systemic and renal hemodynamics. During proximal MIJ, ET-1 may have reached the macula densa during the time preceding the beginning of collection and interruption of the delivery of fluid to the distal nephron. ET-1 directly stimulates fractional and absolute volume reabsorption along the proximal tubule. Proximal secretion and/or filtration of ET-1 could represent a physiological mechanism to activate the tubuloglomerular feedback, eliciting a response opposite to that triggered by systemic and intrarenal infusion.

Pressure flow study data in a group of asymptomatic male control patients 45 years old or older

PURPOSE

The role of pressure flow studies in the routine evaluation of patients with benign prostatic hyperplasia remains a controversial issue in urological practice. There are little data on age matched asymptomatic control groups. We evaluated pressure flow findings in such a group.

MATERIALS AND METHODS

A total of 24 male patients 47 to 80 years old (mean age 62.5) attending a general surgical clinic were recruited for study after ethical committee approval. The volunteers had never sought medical attention for urinary symptoms and did not perceive themselves as having a urological problem. Volunteers were assessed by International Prostate Symptom Score (I-PSS) and Madsen symptom score, clinical examination, free uroflowmetry, post-void residual ultrasound, repeat pressure flow studies and transrectal ultrasonography. Pressure flow tracings were manually analyzed for standard urodynamic values and the degree of bladder outflow obstruction according to recognized International Continence Society, Abrams-Griffith nomogram, linear passive urethral resistance relation and urethral resistance factor classifications.

RESULTS

Median I-PSS was 2.0 (interquartile range 1.2 to 5.7). For I-PSS quality of life the median was 1.0 (interquartile range 0.75 to 2.0). On pressure flow studies 3 patients (13%) had unequivocal obstruction, 7 (29%) were in the equivocal area and 14 (58%) had no obstruction, while 15 (63%) had unstable contractions on medium fill cystometry.

CONCLUSIONS

The data show that a surprising number of apparently normal men are obstructed by commonly used criteria. This finding confirms asymptomatic obstruction, suggesting that obstruction may be less important in the development of symptoms than previously thought. Also, until the natural history of obstruction is more clearly defined surgery in obstructed asymptomatic patients is probably unwise.

Mechanisms of regulation of cell adhesion and motility by insulin receptor substrate-1 in prostate cancer cells

LNCaP cells are human prostatic cancer cells that have a frame-shift mutation of the tumor suppressor gene PTEN and do not express the insulin receptor substrate-1 (IRS-1), a major substrate of the type 1 insulin-like growth factor receptor (IGF-IR). Ectopic expression of IRS-1 in LNCaP cells increases cell adhesion and decreases cell motility by an IGF-I-independent mechanism. We show now that these effects of IRS-1 are accompanied by serine phosphorylation of IRS-1 and are inhibited by inhibitors of phosphatidylinositol 3-kinase (PI3K). We have confirmed the requirement for PI3K activity and serine phosphorylation by the use of IRS-1 mutants, expressed in LNCaP cells. Serine phosphorylation inhibits IGF-I-induced tyrosyl phosphorylation of IRS-1, which is restored by the expression of wild-type PTEN or by inhibition of PI3K activity. Finally, IRS-1 in LNCaP cells co-immunoprecipitates with integrin alpha 5 beta 1, and the association is again IGF-I-independent. We conclude that in LNCaP cells, IRS-1 is serine phosphorylated by PI3K, generating effects that are different, and even opposite, from those generated by IGF-I.

Taurine and osmoregulation: platelet taurine content, uptake, and release in type 2 diabetic patients

In this study, plasma and platelet taurine content and fluxes were determined in 38 type 2 diabetic patients and in 26 healthy control subjects. Taurine levels in diabetic patients were significantly lower than in control subjects both in plasma (32.1 v 48.6 micromol/L, P = .000) and platelets (148 v 183 nmol/mg protein, P = .043). Platelet taurine uptake in diabetic patients was significantly reduced (321.2 v 524.9 pmol total taurine 10(8) platelet(-1) min(-20), P = .000), whereas taurine release increased in comparison to healthy controls (38.7 v 29.5% of platelet 3H taurine at the start of incubation, P = .000). These results may reflect modified systems of taurine carriers or a compensatory mechanism in response to an increase of other organic osmolytes.

[Perforated duodenal diverticulum: report of a case]

After the colon, the duodenum is the most common site of diverticula. Duodenal diverticula can be divided into two types: intraluminal or extraluminal. The latter are more frequent, with a prevalence ranging from 0.6 to 27% in relation to the diagnostic methods utilized. Females are more often affected than males. About 70-75% of extraluminal duodenal diverticula are located in a circular area centred around the ampulla of Vater within a radius of 2-3 cm; these are defined as periampullary or juxtapapillary. Perforation is the rarest type of complication and can simulate different clinical conditions. CT plays a fundamental role in diagnosis also in relation to the different diverticular topography. Perforation is an indication for emergency surgery. The authors describe the clinical case of a duodenal diverticulum containing the outlet of the papilla, complicated by perforation; CT showed retroduodenal fluid and free air. Emergency surgery with an external biliary drainage, naso-biliary probe, and a diverticulo-jejunostomy on a Roux-en-Y defunctionalised loop, resolved the condition.

An information-theoretic approach to automatic query expansion

Techniques for automatic query expansion from top retrieved documents have shown promise for improving retrieval effectiveness on large collections; however, they often rely on an empirical ground, and there is a shortage of cross-system comparisons. Using ideas from Information Theory, we present a computationally simple and theoretically justified method for assigning scores to candidate expansion terms. Such scores are used to select and weight expansion terms within Rocchio's framework for query reweigthing. We compare ranking with information-theoretic query expansion versus ranking with other query expansion techniques, showing that the former achieves better retrieval effectiveness on several performance measures. We also discuss the effect on retrieval effectiveness of the main parameters involved in automatic query expansion, such as data sparseness, query difficulty, number of selected documents, and number of selected terms, pointing out interesting relationships.

Androstanolone treatment for congenital penile curvature

OBJECTIVES

To test the etiological hypotheses of congenital penile curvature (CPC) and to infer the possible therapeutic approaches.

MATERIALS AND METHODS

Seventy patients affected by CPC were enlisted for the present study: 37 with left curvature, 21 with ventral curvature, 11 with left ventral-lateral curvature, and 1 with right curvature. All patients under the age of 21 years were encouraged to take local medical therapy with alcohol androstanolone gel in a dosage of 0.15 mg/cm(2) of surface area. Group A (17-43 years of age) consisted of patients who refused medical therapy and decided to solve their problem with surgery. They underwent Nesbit's operation and were given a contralateral biopsy of the tunica albuginea at the same time. Cytoplasmic androgen receptors (CARs) were quantified in the tunica albuginea of both cavernous bodies (CBs). Group B consisted of 26 patients aged between 4 and 21 years who were given local medical therapy with androstanolone in alcohol gel. They underwent a maximum of 3 therapy cycles each lasting 2 months with a 1-month suspension between each. Group C consisted of 9 patients (27-53 years of age) who were fathers of 9 group B patients. These adults were also affected by penile curvature and taken into consideration as a control group because we have observed three spontaneous corrections of penile curvature in puberty.

RESULTS

CARs research in group A and in 6 group B patients under the age of 20 revealed a 2-5 times reduction on the concave part of the cavernous body compared to the contralateral one. This difference progressively decreased in older patients. In group B, 14 patients aged between 4 and 15 years and 1 aged 17 (53.8%) were treated with a local androstanolone therapy and the result was a regression in the curvature between 30 and 100%. Another 9 patients aged between 17 and 21 years did not show any improvement despite androstanolone treatment.

CONCLUSIONS

The results show a 2-5 times reduction in CARs on the hypoplastic cavernous body of young male patients. These differences progressively decreased in older patients. The positive results of the androstanolone therapy in patients under the age of 15 and the negative ones in older patients are certainly related to the quantity of CARs present on the tunica albuginea.

Overexpression of protectin (CD59) down-modulates the susceptibility of human melanoma cells to homologous complement

The clinical efficacy of therapeutic complement (C)-activating monoclonal antibodies (mAb) to melanoma-associated antigens can be impaired by the levels of expression of C-inhibitory molecules on neoplastic cells. Protectin (CD59) is a glycosylphosphatidylinositol (GPI)-anchored cell membrane glycoprotein, acting as terminal regulator of C cascade, which is heterogeneously expressed in melanomas and represents the main restriction factor of C-mediated lysis of melanoma cells. Thus, we investigated whether the overexpression of CD59 could influence the constitutive susceptibility of distinct melanoma cells to homologous C. Infection of CD59-positive Mel 100 and 70-W melanoma cells by a retroviral vector carrying the CD59 cDNA, significantly (P < 0.05) upregulated their constitutive expression of CD59, whereas it did not affect that of additional C-regulatory molecules. Transduced CD59 was entirely GPI-anchored and showed a molecular weight identical to native CD59. Additionally, higher amounts of soluble CD59 were detected in the conditioned media of CD59-transduced melanoma cells compared with parental cells. CD59-transduced melanoma cells, sensitized by the anti-GD3 disialoganglioside mAb R24, were significantly (P < 0.05) less susceptible to homologous C-lysis than were parental cells; this effect was fully reverted by the masking of CD59 with F(ab')(2) fragments of the anti-CD59 mAb YTH53.1. These results provide conclusive evidence demonstrating that absolute levels of CD59 expression regulate the susceptibility to homologous C of specific melanoma cells, and suggest an additional explanation for the poor clinical results obtained with C-activating mAb in the clinical setting.

Effect of insulin and sulfonylurea therapy, at the same level of blood glucose control, on low density lipoprotein subfractions in type 2 diabetic patients

The aim of this study was to evaluate the effect of sc insulin (INS) compared with sulfonylurea (SUL) therapy, at the same level of blood glucose control, on the low density lipoprotein (LDL) subfraction profile in normolipidemic type 2 diabetic patients. Nine normolipidemic type 2 diabetic men (age, 56+/-3 yr; body mass index, 26.5+/-0.9 kg/m2; mean +/- SEM), after a 3-week wash-out period, were assigned to INS or SUL for 2 months in a randomized cross-over design. Doses were adjusted only during the first month and then were kept constant. At the end of the treatments, hemoglobin A1c, plasma lipids, LDL, and very low density lipoprotein (VLDL) subfraction profiles and plasma postheparin lipoprotein lipase and hepatic lipase (HL) activities were evaluated. Despite glucose control was similar at the end of both periods (hemoglobin A1c, 7.4+/-0.3% vs. 7.0+/-0.2%, INS vs. SUL), INS compared with SUL significantly reduced plasma triglyceride (0.9+/-0.1 vs. 1.1+/-0.1 mmol/L; P < 0.05). Although INS did not affect the LDL concentration, it induced a decrease in both the amount (59.0 = 9.8 vs. 76.1+/-16.8 mg/dL; P = NS) and the proportion (31.2+/-3.0% vs. 38.3+/-3.8%; P < 0.03) of small LDL. Moreover, the decrease in small LDL was positively related to the reduction of large VLDL (r = 0.67; P < 0.04) and HL (r = 0.69, P < 0.05) induced by insulin therapy. In conclusion, sc insulin therapy, independently of glucose control and even in the presence of quite low plasma triglyceride levels, is able to reduce small LDL particles in type 2 diabetic patients. This change is related to decreases in both HL activity and large VLDL particles.

Regional differences in signalling transduction pathways among smooth muscle cells from rabbit colon

Smooth muscle cells (SMC) from the circular muscle layer of rabbit colon, taken from the proximal and distal regions that are known to have different physiological and motor activities, were used to highlight distinct regional intrinsic myogenic properties and to investigate the correlations between receptor and signalling transduction pathways. Contractile agonists were shown to be more potent on proximal than on distal SMC in inducing contraction and intracellular Ca(2+) increase. Concentration-response curves of agonists-induced Ca(2+) increase were constantly shifted to the right, though remaining parallel, with respect to contraction curves, independently of the region analysed. Using agents activating different steps of cAMP-or cGMP-mediated intracellular cascades, main regional differences were revealed as far as relaxation was concerned. Relaxation of proximal SMC was found to be essentially cGMP mediated, while that of distal SMC was cAMP mediated. In conclusion, the motor patterns of the two regions appear to be influenced by distinct regional biochemical characteristics that are intrinsic to colonic SMC.

[Description of a particular case of the so-called Schmincke lymphoepithelioma and study of the correlation with Epstein-Barr virus]

For poorly differentiated rhinopharyngeal carcinomas, the clinical presentation (association with the Epstein-Barr virus, paraneoplastic syndromes, onset of lymphoma) and the histopathological features can be polymorphous and they can confound or delay diagnosis and preparation of an adequate treatment plan (radio-chemotherapy). Often these neoplasms arise as clinically primitive laterocervical metastases, masked by clinical findings and a history that can lead to the mistaken diagnosis of systemic lymphoproliferative processes such as Hodgkin's disease. Here an observation of this type is presented in a young patient (19 years old) who came under observation for a laterocervical tumefaction recurrent from a previous exeresis performed at another hospital and symptoms of serotine febricula, dysphagia and serology positive for the Epstein-Barr virus (EBV). The patient underwent surgery and then radiotherapy and has been under close post-operative follow-up for two years. To date the patient's condition--both local and general--is good. The particular histology of the neoformation lies in the abundant infiltration of plasma cell and lymphocyte eosinophils, at times in blastic form. Moreover, elements with a large clear nucleus and evident nucleolus (Hodgkin-like) and scattered multinucleate Langhans-type giant cells can be seen. Immunohistologically the tumor cells markedly express for cytokeratin and the latent membrane protein (LMP1) of the Epstein-Barr virus (EBV) and show a high growth fraction. Under the electron microscope, the plurinucleate giant cells present large nuclei with morphology similar to that of tumor cells. The clear cytokeratin-positivity of the tumor elements and the histological and ultrastructural features mentioned led to the diagnosis of a massive metastasis from lymphoepithelial carcinoma, the Schmincke variant, plus EBV infection of the neoplastic cells. The authors conclude assuming that the particular granulomatous reaction is due to the host's reaction to the tumor cells, but also to the reaction to the viral antigens. In the former case we find an attempt to limit the carcinomatous process; in the latter it is a response caused by the EBV and is not, apparently, aimed at protecting against the neoplasm rather it facilitates the neoplastic process.

Evaluation of 8-hydroxydeoxyguanosine in human oral cells: the importance of tobacco smoke and urban environment

The DNA adduct 8-hydroxydeoxyguanosine (8-OHdG) has been widely used as a sensitive biomarker for oxidative damage. To investigate the role of environmental factors on oxidative DNA damage formation, the level of 8-OHdG was determined in oral cells from 109 healthy volunteers by an immunohistochemical method. A statistically significantly higher content of 8-OHdG was detected in oral cells from smokers (111 +/- 55, n = 38) compared with non smokers (78 +/- 48, n = 71), (p < 0.01). Moreover, subjects living in an urban area showed a higher level of oxidative damage with respect to those living in a countryside-suburban area (99 +/- 53, n = 58 vs. 78 +/- 51, n = 51), (p = 0.03). No significant association was detected between 8-OHdG in oral cells and other variables such as passive smoke, oral infections, alcohol or vitamin intake and grilled food consumption. This work suggests that tobacco smoke and environmental exposure to pollutants lead to a measurable increase of oxidative damage in oral cells and confirms that the immunoperoxidase method is an appropriate approach for epidemiological analyses.

Insulin receptor substrate-1, p70S6K, and cell size in transformation and differentiation of hemopoietic cells

After an initial burst of cell proliferation, the type 1 insulin-like growth factor receptor (IGF-IR) induces granulocytic differentiation of 32D IGF-IR cells, an interleukin-3-dependent murine hemopoietic cell line devoid of insulin receptor substrate-1 (IRS-1). The combined expression of the IGF-IR and IRS-1 (32D IGF-IR/IRS-1 cells) inhibits IGF-I-mediated differentiation, and causes malignant transformation of 32D cells. Because of the role of IRS-1 in changing the fate of 32D IGF-IR cells from differentiation (and subsequent cell death) to malignant transformation, we have looked for differences in IGF-IR signaling between 32D IGF-IR and 32D IGF-IR/IRS-1 cells. In this report, we have focused on p70(S6K), which is activated by the IRS-1 pathway. We find that the ectopic expression of IRS-1 and the inhibition of differentiation correlated with a sustained activation of p70(S6K) and an increase in cell size. Phosphorylation in vivo of threonine 389 and, to a lesser extent, of threonine 421/serine 424 of p70(S6K) seemed to be a requirement for inhibition of differentiation. A role of IRS-1 and p70(S6K) in the alternative between transformation or differentiation of 32D IGF-IR cells was confirmed by findings that inhibition of p70(S6K) activation or IRS-1 signaling, by rapamycin or okadaic acid, induced differentiation of 32D IGF-IR/IRS-1 cells. We have also found that the expression of myeloperoxidase mRNA (a marker of differentiation, which sharply increases in 32D IGF-IR cells), does not increase in 32D IGF-IR/IRS-1 cells, suggesting that the expression of IRS-1 in 32D IGF-IR cells causes the extinction of the differentiation program initiated by the IGF-IR, while leaving intact its proliferation program.

[Biphasic hypopharyngeal synovial sarcoma: ultrastructural, cytofluorometric and immunohistochemical study and brief review of the literature]

Synovial sarcomas account for 7-10% of all soft tissue malignancies and the rare head and neck region location accounts for an average 5% of them. A brief review of the data in the Literature has shown that not more than one hundred cases of cervical-facial synovial sarcoma have been reported. In the head and neck locations this form of tumor is significantly less aggressive, with a higher survival rate and a recurrence rate much lower than the 60-70% shown for other locations in the limbs. After a brief review of the Literature, Authors present a rare clinical case of hypopharyngeal synovial sarcoma which recently came under observation. Despite the accurate diagnostic procedure, after surgical removal of the tumor by CO2 laser microlaryngoscopy, diagnosis required the use of histological and ultrastructural techniques. CT and NMR of the neck using contrast medium showed that the structure of the neoformation was similar to that of the soft tissues, it was 3-4 cm in diameter, located in the hypopharynx and had an extensive surface in contact with the left glossoepiglottic groove. The lesion appeared to involve the free edge of the aryepiglottic fold, coming into contact with the free edge of the epiglottis; it could not be dissociated form the epiglottis and obliterated both the homolateral glossoepiglottic vallecula and the pyriform sinus. Structural analysis after radiography with a contrast medium showed a marked impregnation of the lesion, indicative of high degree of vascolarization. Ultrastructural, cytofluormetric and immunohistochemical analyses were performed on the neoplasm in order to process all these data together with the clinical parameters; in other words a multi-parameter evaluation was performed, as suggested by other Authors, to determine the therapy and arrange more accurate monitoring of this patient, victim of a neoplasm with a high potential for metastases.

Human dbl proto-oncogene in 85 kb of xq26, and determination of the transcription initiation site

The dbl oncogene is generated by substitution of the 5' portion of its normal counterpart with an unrelated human sequence. To analyze the genomic structure and transcriptional regulation of the dbl proto-oncogene, we have isolated human genomic clones containing the entire human proto-dbl gene, localized in Xq26. Restriction mapping of a 600kb YAC clone (yWXD311) placed proto-dbl about 50kb telomeric to the coagulation Factor IX gene. The genomic DNA fragment containing the 5' end of proto-dbl was subcloned into plasmid vectors and the nucleotide sequences of exon 1, the flanking intronic region and genomic DNA 5' of the first codon were determined. Sequence analysis of 85119bp from the region revealed the genomic structure of proto-dbl. It contains 25 exons coding for a 4.7kb transcript including large 5'- and 3'- (1218bp and 701bp, respectively) untranslated regions (UTRs). RNase protection and primer extension assays on RNA from medullary thyroid carcinoma (TT) cells, which normally express dbl, revealed a transcription start site 1218bp upstream of the ATG of the first exon. A 1.6kb genomic 5' of the translation start sites drives the expression of a CAT-reporter in transient transfections in the TT cell line, though lacking TATA or CAAT boxes.

Systemic and intratubular effects of cyclosporin-A and tacrolimus on the rat kidney

Cyclosporin-A and tacrolimus can cause hypertension and renal failure through endothelin receptors. The importance of tubular function was never investigated. The aim of this study was to compare the effects of intratubular injection of cyclosporin-A and tacrolimus with effects observed during systemic infusion. In 20 rats, either cyclosporin-A or tacrolimus was infused, 30 and 1 mg/kg i.v., respectively, in 30 min. Before and after administration, glomerular filtration rate, single nephron filtration rate, proximal and distal absolute reabsorption and percent reabsorption were measured by clearance and micropuncture techniques. In 22 other rats, single nephron filtration rate, absolute reabsorption, percent reabsorption, were measured at the last proximal and early distal tubules before and during intraluminal microinjection of either cyclosporin-A or tacrolimus. During cyclosporin-A and tacrolimus i.v. infusion, glomerular filtration rate fell from 536+/-43 to 448+/-37 microl/min (P<0.026) and from 408+/-33 to 284+/-81 microl/min (P<0. 02), single nephron filtration rate from 26.4+/-2.0 to 20.6+/-1.9 (P<0.002) and from 21.6+/-2.2 to 17.4+/-2.0 nl/min, respectively (P<0.02). The last proximal absolute reabsorption remained unchanged with cyclosporin-A (16.8+/-2.2 vs. 15.1+/-1.7 nl/min, P>0.444), but was slightly reduced by tacrolimus (14.4+/-1.7 vs. 11.3+/-1.7 nl/min, P<0.05). During microinjection, single nephron filtration rate was increased by cyclosporin-A (20+/-1 vs. 63+/-8 nl/min, P<0.0001), and tacrolimus (from 17+/-2 to 49+/-9 nl/min, P<0.0001), and so was reabsorption, independent of the sampling site. Cyclosporin-A and tacrolimus, indeed, raise single nephron filtration rate directly when injected intraluminally. Since this effect occurs in the direction opposite to that recorded during systemic infusion, it must be mediated through different pathways. The i.v. infusion of cyclosporin-A, but not tacrolimus, impairs glomerulo-tubular balance.

8-hydroxy-2'-deoxyguanosine in cervical cells: correlation with grade of dysplasia and human papillomavirus infection

In this study, the 8-hydroxy-2'-deoxyguanosine (8-OHdG) level was assessed in human cervical cells by an immunoperoxidase method and was related to the presence of human papillomavirus (HPV) infection and precancerous lesions. After optimizing the immunohistochemical method of detecting oxidative DNA damage in whole cells, we have used this technique to estimate the oxidative damage in cervical cells collected during a routine PAP test. The analysis of variance (ANOVA) of the data from human samples showed significant differences in the 8-OHdG content among normal, low-grade and high-grade squamous intraepithelial lesion (SIL, HGSIL and LGSIL, respectively; P < 0.001). In the comparison of the three groups, statistically significant differences were detected between normal SIL and HGSIL (P < 0.001) and between LGSIL and HGSIL (P = 0.003), whereas no statistically significant difference was found between normal SIL and LGSIL (P = 0.1). Grouping observations by HPV status, no significant difference was detected in 8-OHdG levels between HPV(+) and HPV(-) subjects (P = 0.8). The polytomous and proportional odds models, extensions of the logistic regression analysis, showed that the effect of 8-OHdG levels in rising the risk of dysplasia was roughly constant through SIL grades. In conclusion, the immunoperoxidase method, applied to single human cervical cells, provides clear evidence that significant differences exist in 8-OHdG content between normal and dysplastic cells and that oxidative DNA damage might play an important role in cervical carcinogenesis.