Fibrinogen adsorption and platelet lysis characterization of fluorinated surface-modified polyetherurethanes.

A polyetherurethane (PU) was modified using fluorinated surface-modifying macromolecules (SMMs). A double radiolabel method was used simultaneously to measure the number of adhered platelets ((51)Cr) and the quantity of adsorbed Fg ((125)I), in a cone-and-plate instrument. The objectives were to determine if adsorbed Fg levels correlated to platelet adhesion on the surfaces, and to assess if any reductions in platelet adhesion for the SMM-treated surfaces resulted from surface-induced platelet lysis, rather than changes directly related to lower platelet activation and attachment on the novel surfaces. Platelet lysis was determined from lactate dehydrogenase (LDH) and unbound (51)Cr released into plasma isolated from whole blood exposed to test materials. The corresponding Fg adsorption, evaluated under the same platelet adhesion conditions, did not account for the reduced platelet adhesion on the treated surfaces. LDH and (51)Cr platelet release were very low and indicated no statistically significant differences between the materials. It was therefore concluded that platelet lysis did not contribute to the reduction in platelet adhesion characteristic observed on the SMM-treated surfaces. More importantly, the work emphasizes that the platelet activation cannot be inferred to by assessing the quantity of fibrinogen as is commonly done in the literature. The finding suggests a much more complex mechanism of action for the SMM surface modifiers. On-going work is investigating other Fg parameters such as protein binding affinity and protein conformational state in order to establish the mechanism by which the fluorinated surface modifiers may be reducing platelet adhesion via intermediary changes in initial protein adsorption.

Fibrinogen surface distribution correlates to platelet adhesion pattern on fluorinated surface-modified polyetherurethane.

In previous work, it had been shown that platelet adhesion could be reduced by fluorinating surfaces with oligomeric fluoropolymers, referred to as surface-modifying macromolecules (SMMs). In the current study, two in vitro blood-contacting experiments were carried out on a polyetherurethane modified with three different SMMs in order to determine if altered platelet adhesion levels could be related to the pattern of adsorbed protein and more specifically to the manner in which fibrinogen (Fg) distribution occurs at the surface. In the first experiment, the materials were placed in whole human blood and the adherent platelets were viewed with high-resolution scanning electron microscopy (SEM). In a second experiment, the materials were incubated with human plasma with the absence of platelets. The plasma contained 5% fluorescent-Fg. The materials were then viewed with a fluorescence microscope and images were collected to define the distribution of high-density fluorescent-Fg areas. The SEM and fluorescent-Fg images were imported to Image Pro Plus imaging software to measure the area, length and circularity and a bivariate correlation test was conducted between the two sets of data. For area and length morphology parameters, there were high and significant correlations (r > 0.9, p < 0.05) between the platelets and Fg aggregates. The data suggest that the Fg distribution may serve as a predictor of platelet morphology/activation and provides insight into the non-thrombogenic character of biomaterials containing the fluorinated SMMs.

Antiinflammatory activity of a series of substituted 2,3-dihydro-6-hydroxypyrimido[2,1-f]purine-4,8(1H,9H)-diones.

A series of substituted analogues based on the novel 2,3-dihydro-6-hydroxypyrimido[2,1-f]purine-4,8(1H,9H)-dione ring system have been synthesized and shown to exhibit antiinflammatory activity in the adjuvant-induced arthritis rat model (AAR). The activity exhibited by the pyrimidopurinediones in this model of chronic inflammation is comparable to that of their previously studied 2-oxo congeners, the 6-hydroxypyrimido[2,1-f]purine-2,4,8-(1H,3H,9H)-triones, the best of which show potency levels approximately equal to that of naproxen. On the basis of its potency in the AAR assay, 9-benzyl-2,3-dihydro-1,3-dimethyl-6-hydroxy-7-(3-methyl-2-butenyl) pyrimido-[2,1-f]purine-4,8(1H,9H)-dione was selected for further evaluation and found to exhibit cyclooxygenase inhibitory activity in the in vitro rat neutrophil model. With respect to side-effect liability, this prenylated derivative has been shown to be devoid of gastric ulcer inducing potential, as well as the ocular toxicity observed previously with the 2-oxo series.

A host-mediated in vivo/in vitro assay with peritoneal murine macrophages for the detection of carcinogenic chemicals.

We have developed a host-mediated assay system for the detection of the transforming action of chemical carcinogens on peritoneal macrophages. Directly as well as indirectly acting carcinogenic substances administered intraperitoneally to NMRI mice could be examined in this way. Resident macrophages were recovered by peritoneal lavage from treated and untreated mice and were cultured in soft agar. After 5-6 days normal and transformed cells could be distinguished. Statistical analysis comparing cells, for example, from alpha-naphthylamine or diphenylhydantoin-treated animals with those from control mice proved that the test is positive at least on a significance level of 5% using the t-test. Further substances revealing a cell-transformation potential were benzene, benz(a)pyrene, 2,3,7,8-tetrachlorodibenzodioxin, N-nitrosodimethylamine, ethidium bromide, aflatoxin B1,N-methyl-N-nitrosourea, 1-methyl-3-nitro-1-nitrosoguanidine, 2-naphthylamine, dieldrin, suramin and trichloroethylene. A weak transforming potential was found for chlorambucil as well as for tetrachloroethylene. With toluene or azidothymidine no cell transformation could be observed. Several immortal cell lines could be established form NMRI mice treated with alpha-naphthylamine or N-methyl-N-nitrosourea. Athymic nu/nu mice injected subcutaneously with these cells developed tumors, establishing the oncogenic potential of these cell lines.

Pre-operative localization of non-palpable lesions in breast cancer by charcoal suspension.

The use of preoperative localization procedures for non-palpable breast lesions (NPBL) is becoming more and more widespread, increasing the detection of early breast cancers. From October 1987 to July 1992, at our Institution, 253 patients (pts) with clinically non-palpable lesions underwent surgical treatment. Of the 253 pts, the lesions have been localized in 95 cases by a needle system, and in the other 158 cases by a dye injection of a 3% sterile charcoal suspension using stereotactic method (118 cases) or sonography (40 cases). The patients' mean age was 53 years (range 30-75). Mammography revealed regular opacities in 133 cases, clustered microcalcification in 75, diffuse microcalcification in 24, opacities with irregular borders in nine and opacities with internal microcalcifications in 12. The histological findings showed benign breast disease in 175 cases (69.2%), borderline breast disease in 23 (9.1%) and malignancy in 55 (21.7%). The benign/malignant/borderline lesions ratio was 3.2:1. The majority (70%) of these malignant lesions were small cancers (less than 1 cm in diameter) and without lymph-node involvement. The biopsy cost (benign/malignant/borderline ratio, patients discomfort and cosmetic result) has been acceptable.

Cell transforming and oncogenic activity of 2,3,7,8--tetrachloro--and 2,3,7,8 tetrabromodibenzo-p-dioxin.

We have developed a host-mediated assay system for detection of the transforming activity of chemical carcinogens on peritoneal macrophages, directly, as well as indirectly acting carcinogenic substances administered intraperitoneally to NMRI mice could be examined in this way. Resident macrophages were recovered by peritoneal lavage from treated and untreated mice and cultured in soft agar. After 5-6 days normal and transformed cells could be distinguished. Statistical analysis comparing cells from 2, 3, 7, 8-tetrachlorodibenzo-dioxin (TCDD)-treated animals with those from control mice proved that the test is positive at least on a significance level of 5%, using the t-test. TCDD revealed a cell-transforming potential that showed a dose-dependent response in this host-mediated assay. The co-carcinogenic activity of TCDD was established in experiments with diphenylhydantoin. Low doses of diphenylhydantoin which did not exhibit any transforming potential in our system gained a high oncogenic potential by the simultaneous administration of low doses of TCDD, which also had no transforming activity. We have compared the cell transforming potential of TCDD with its bromo analog TBrDD. The cell transforming potential of TCDD is 7 times that of TBrDD. We have succeeded in establishing a permanent cell lined from mice treated with TBrDD. The oncogenicity of this cell line was tested in athymic nu/nu mice. Animals treated subcutaneously with these cells (1 x 10(6) cells) developed tumors at the injection site. Using monospecific antibodies to tumor necrosis factor alpha (TNF-alpha), we have found that TCDD stimulates the secretion of TNF-alpha. The experimental data reported here lead to the conclusion that TCDD has a carcinogenic as well as a co-carcinogenic activity and has the property to induce TNF-alpha.

Feasibility of thymidine labelling index on fine needle aspirates from breast cancer: comparison with surgical samples.

Fine-needle aspiration (FNA) provides a suitable diagnostic tool in the management of patients with breast cancer lesions. The current study reports on tumor proliferative activity, by 3H-Thymidine Labelling Index (TLI), assessed on 59 FNA (TLI1) and 28 surgical specimens (TLI2) from the same breast cancer patients. Median TLI values from FNA and surgical material were 1.0% and 0.7%, respectively. In the 28 patients, evaluable for the comparison between TLI1 and TLI2, the association was found to be highly significant (p = 0.000). Moreover, no change in tumor proliferative activity was observed in the majority (79%) of cases when evaluated preoperatively and at surgery. This study confirms the feasibility of TLI analysis on FNA from breast cancer and provides results superimposable on those obtained in a tissue sample from the same patient.

Correlation between mammographic and thermographic patterns. Use of thermography as a possible pre-screening procedure in patients at risk for breast cancer.

The purpose of this study is to investigate the relationship between mammographic patterns according to Wolfe's classification and thermographic vascular patterns. The Authors report the results of their experience in 154 cases.

[Treatment of upper limb lymphedema after mastectomy with escine and levo-thyroxine]. / Trattamento del linfedema dell'aorto superiore conseguente a mastectomia con escina e levo-tiroxina.

Lymphoedema of the upper limb is the most serious and most crippling complication of mastectomy. An account is given of the factors possibly responsible, and a classification of the different forms is proposed. When fibrosis has set in, treatment is followed by very disappointing results, being at best able to bring about a partial, but transitory reduction in limb volume and consistency. Reference is also made to results obtained in 70 cases with two substances, 1-thyroxine and escine (somatoline), applied by massotherapy in postural drainage, ionophoresis, and pressotherapy, according to the requirements of each case. The results were distinctly satisfactory, though the outstanding fact was the maintenance of the response throughout many follow-up controls. It is felt, therefore, that somatoline can be usefully given in cyclic form, both in cases treated in an early stage, and also in all patients were lymphoedema is a likely risk after mastectomy.

[Cigarette smoking. A pilot project of dehabituation and experimental research]. / Fumo di sigaretta. Un progetto pilota di disassuefazione e una ricerca sperimentale.

An interdisciplinary approach was adopted in a pilot programme research project as the most effective way to obtain concrete results in curing tobacco-addiction. The various stages and effects of the treatment are analysed as a means of identifying the most appropriate techniques. The early results are reported under separate headings according to treatment type (psychological, neurophysiological, dietary, clinical, chemical).

Non palpable breast lesions: preoperative sonographic localization.

From 1987 to 1992 at our Institute, 253 patients with non palpable breast lesions (NBPL) underwent a surgical excision. Fifty-one lesions (19.7%) were localized by an injection of a sterile 3% charcoal suspension under sonographic guide. The sonographic features of NBPL were classified as follows: positive in one case (2%), doubtful in 31 cases (60%) and negative in 19 cases (38%). According to our data the preoperative sonographic localization is a useful alternative procedure to stereotactis mammography in case of breast masses and/or areas of increased tissue density or distorted breast architecture.

Sentinel lymph node biopsy for sparing axillary dissection in selected patients with breast cancer.

Axillary lymph nodal status in breast cancer remains one of the more important prognostic factors. In early breast cancer axillary lymph node metastasis are found only in 10-18%. It can be deduced that in all these patients a complete axillary dissection is an overtreatment. The concept of sentinel lymph node (SN) was applied to breast cancer. Of course if SN examination gives negative findings, the patient will avoid axillary lymphadenectomy. 134 patients with localized breast cancer were evaluated for enrollment into the study. In 40 (29.8%) patients lymphoscintigraphy was performed together with an injection of vital dye to identify the SN, in 94 (70.1%) only vital dye was utilized. The mapping procedure was successful in 129 cases (96.2%). In our study there was concordance between SNs and axillary nodes in 120 out off 124 cases (96.7%). The false-negative rate was 4.8% (4/83). The overall sensitivity of the SN biopsy was 91.1% (41/45), with a negative predictive value of 95.1% (79/83). Five patients had SN negative and they decided do not undergo axillary lymphadenectomy. This study demonstrates that accurate SN identification was obtained combining lymphoscintigraphy and blue dye. Moreover, each method requires a suitable learning curve. After an accurate training, complete axillary lymphadenectomy can be avoided in selected patients.

Concanavalin-A binding to acetylcholine receptors: identification of two forms of receptor in denervated rat muscle.

The interaction of the nicotinic acetylcholine receptor from denervated rat muscle (AChR, solubilized in Triton X-100) and Concanavalin-A (Con-A) was studied by soluble Con-A competing with the binding of AChR to agarose immobilized Con-A, by immuno-precipitation of Con-A-AChR complexes and by inhibition of alpha-bungarotoxin binding to AChR. Results showed that Con-A bound to 85% of all AChR molecules at multiple cooperative binding sites. Con-A caused a partial inhibition of toxin binding to a maximum of 41% of receptors, but only when AChR was first incubated with Con-A before toxin labeling and not when the order was reversed. The blockade of toxin labeling was reversed when the Con-A-AChR complexes were treated with mannose (0.75 M). Receptor-Con-A complexes in which toxin binding was not inhibited showed saturation binding of toxin with a decreased apparent affinity. A sub-population of AChR prepared by affinity purification on Lens Culinaris lectin-agarose columns was 100% inhibited from toxin binding when preincubated with Con-A. We conclude that receptors from denervated rat muscle which bind Con-A (85% of the total AChR) contain two major subpopulations of AChR in the approximate proportions 6:4 that can be distinguished by interactions with lectins having specificity for mannose.

Heterogeneity of acetylcholine receptors: different forms of receptor distinguished by alpha-bungarotoxin kinetics and by antibody binding properties.

The interactions of the nicotinic acetylcholine receptor (AChR), extracted from denervated rat hindlimb muscle, with alpha-bungarotoxin, Concanavalin-A (Con-A) and immunoglobulins isolated from the sera of specific patients with Myasthenia Gravis (MG) have been studied. The association and dissociation of toxin to unfractionated receptors [hydroxylapatite (HTP)-AChR] were best described in terms of two classes of kinetically distinct toxin binding sites present in approximately equal amounts. Incubation of these receptors with soluble Con-A decreased the total toxin-binding capacity by a maximum of 42%. Kinetic studies indicate that the Con-A-induced inhibition of toxin binding is restricted to those toxin binding sites having the fast rate of association with alpha-bungarotoxin. Incubation of HTP receptors with toxin blocking antibodies (MG-B) from MG patient sera decreased the toxin binding capacity by a maximum of 30%. By contrast, receptors fractionated by elution from Lens-Culinaris agarose affinity columns exhibited only fast rates of association and dissociation with alpha-bungarotoxin and represented 40% of the total HTP-AChR population. Con-A totally prevented toxin binding whereas MG-B antibodies had no blocking effect on this subpopulation of receptors. Another MG antibody type which interferes with lectin binding to AChR (MG-C antibody) gave a 50% maximum inhibition of both HTP- and Lens culinaris agarose-AChR. This suggests that both types of toxin binding sites (fast and slow) may be further divided into two separable subclasses based on their carbohydrate moieties. These results show that multiple forms of AChR occur in denervated muscle. At least two different forms of receptors are present which show distinctive differences in ligand-binding properties and some antigenic determinants.

Abscesses of the breast. US-guided serial percutaneous aspiration and local antibiotic therapy after unsuccessful systemic antibiotic therapy.

PURPOSE: The usual therapeutic approach to acute breast abscesses (ABAs) not responsive to systemic antibiotics is surgical incision and drainage. Our purpose was to assess the efficacy of treating ABAs with serial US-guided percutaneous aspiration and local injection of antibiotics. MATERIAL AND METHODS: Twenty-six patients with 28 ABAs, in whom systemic antibiotic therapy had failed, underwent serial US-guided aspiration with local injection a of large-spectrum antibiotic. The treatment was repeated weekly until complete resolution was observed at clinical and US examination. The volume of the ABAs was calculated before each US-guided aspiration. Follow-up US examinations were performed at 1, 4, and 12 weeks after clinical and US resolution. A comparison betweeen costs of surgical and US-guided treatment of ABAs in our institution was done. RESULTS: In 27 ABAs the treatment was successful: a progressive volume reduction and a complete resolution at clinical and US examination was observed within 1 to 7 weeks. In 1 case only, with a large ABA markedly increased in volume at the second examination, surgical drainage was performed. CONCLUSION: US-guided aspiration with local antibiotic injection is a safe and effective approach to ABAs, cheaper than surgical drainage of these lesions.

Multiple forms of anti-acetylcholine receptor antibody in myasthenia gravis.

Sera of patients with myasthenia gravis (MG) contain anti-acetylcholine receptor (AChR) IgG antibodies (Ab) which have different antigenic specificities. Three Ab types were detected: (1) MG-I, which forms immune complexes with AChR; (2) MG-C, which decreases binding of AChR to concanavalin A; and MG-B, which blocks alpha-bungarotoxin binding to AChR. Sera from 152 MG patients were screened for the Ab types. Sixty-one percent contained MG-I, 26% contained MG-C, 10% contained MG-B, and 5% contained both MG-C and MG-B. The latter Ab types were associated with more severe forms of MG but showed no other clinical correlations. IgG antibodies of defined type were purified, and their interaction with unlabeled and toxin-prelabeled AChR from denervated rat muscle was studied in detail. Receptors are homogeneous with respect to determinants recognized by MG-I, but heterogeneous with respect to determinants recognized by MG-C (3 subpopulations, 22%, 28%, and 50% of AChR) and by MG-B (2 subpopulations, 30% and 70% of AChR). The stoichiometry of AChR interaction with the antibodies indicates that for each toxin-binding site, the receptor is divalent as an antigen for MG-I and MG-C but is tetravalent for MG-B. Denervated muscle AChR appears to be a mixture of at least 3 molecular forms of AChR, each of which has distinct immunological features as well as components common to all the receptor subpopulations.

Tapetal changes in beagle dogs. II. Ocular changes after intravenous administration of a macrolide antibiotic--rosaramicin.

Two studies were conducted to assess the toxicity of rosaramicin (a macrolide antibiotic) when given intravenously for 30 consecutive days to beagle dogs with and without a tapetum lucidum (a light reflecting structure within the choroid of the eye). In the initial study, groups of three tapetal dogs/sex were given 20, 40, or 80 mg of rosaramicin/kg, twice daily. Ophthalmoscopic examination during Week 4 revealed dose-related, bilateral ocular changes characterized by a brown-tan discoloration and general pallor or loss of reflectivity of the normally blue-purple or yellow-green, highly reflective tapetum lucidum. These findings were restricted to the tapetal fundus; recovery occurred between Weeks 4 and 10 of the postdose period. To further investigate these changes, a second study was conducted in which groups of three tapetal dogs were given rosaramicin or erythromycin lactobionate (comparative macrolide antibiotic) at 80 mg/kg, twice daily. A third group of atapetal dogs was given 80 mg of rosaramicin/kg, twice daily. A similar change was observed in tapetal dogs given 80 mg of rosaramicin/kg, twice daily, in the follow-up study, but not in the other two groups. No other compound-related changes were observed in either study. The ocular changes observed in dogs given rosaramicin were reversible and structure-specific, occurring only in animals possessing a tapetum lucidum.

Dynamic helical CT of breast tumors.

PURPOSE: The purpose of our study was to test dynamic helical CT (hCT) in the evaluation of breast tumors. METHOD: Thirty-six patients with 39 suspected lesions underwent breast hCT before and 1, 3, and 8 min after intravenous contrast medium administration. A marked enhancement (> or = 100%) at 1 or 3 min without increase at 8 minutes was considered as the primary indicator for malignancy. Twenty carcinomas, one metastatic non-Hodgkin lymphoma, six fibroadenomas, and six other benign findings were histologically assessed. Six cases had negative fine needle aspiration cytology and at least a 2 year negative follow-up. RESULTS: hCT showed a 100% sensitivity and 83.3% specificity. Considering carcinomas and fibroadenomas, significant differences were found for the percent enhancement at 1 min (p = 0.002) as well as for the density increase or decrease at 3 versus 1 min (p = 0.0035), at 8 versus 1 min (p = 0.0027), and at 8 versus 3 min (p = 0.0180). CONCLUSION: hCT proved to have a high diagnostic efficacy in evaluating breast tumors. Even though it involves some exposure to radiation, it should be considered in patients in whom MR is contraindicated.

Randomized trial comparing two devices: the Palmaz-Schatz stent and the Strecker stent in bail-out situations.

UNLABELLED: To assess whether differences in design (geometry, flexibility) and material (electrostatic behavior) may influence the acute and late outcome following intracoronary stent implantation in the treatment of acute or threatened closure after prolonged balloon inflations, 50 patients were randomized to receive either a Palmaz-Schatz stent (n = 25) or a Strecker stent (n = 25). RESULTS: [table: see text] CONCLUSION: Both Palmaz-Schatz and Strecker stents are equally effective in restoring vessel patency in bail-out situations. The incidence of complications is high and similar for both stents if they were used after failed prolonged balloon inflations. Differences in design and material do not seem to influence the results.