Biomedical subjects
Publications and source records attributed to P Romano.
The Molecular Probe Data Base (MPDB) is designed to collect and make available on-line information on synthetic oligonucleotides. This paper briefly describes the purpose of MPDB, its content and structure, forms and mode of data distribution, and a series of additional services available to scientists using MPDB.
The floc-forming ability of flocculent strains of Zygosaccharomyces bailii and Z. fermentati, isolated from musts, was tested for susceptibility to proteinase and sugar treatments. Z. fermentati was found highly resistant to the proteolytic enzymes tested, whereas Z. baili was only trypsin-resistant. The inhibition of flocculation by sugars distinguished two types: in Z. fermentati flocculation was completely inhibited by mannose, in Z. bailli by various sugars. By SEM observation, the cell surface of Zygosaccharomyces revealed the presence of a column structure, resulting from fusion of vesicles present on the cell surface.
The choice of the esophageal substitute after surgical resection for peptic stricture lies between the colon and jejunum. The current study was designed to compare long-term resistance of the colonic and jejunal mucosa to gastric or mixed duodenogastric secretions. The following preparations were performed in Wistar rats: transposition of a colonic or jejunal patch (a) to the gastric body, with or without truncal vagotomy, or (b) to the gastric antrum and proximal duodenum, with or without truncal vagotomy. Jejunal and colonic patches were removed 4, 8, and 12 months after surgery. The only damage to the transposed mucosae was the alteration of microvilli. The alteration was more severe in colonic than in jejunal patches and was prevented by truncal vagotomy. Long-term resistance of the transposed mucosae to the environmental challenge may depend on their adaptation potentiality, involving both specific and nonspecific mechanisms. Nonspecific mechanisms include the increased production of mucus and the gastric-like transformation of the superficial epithelial layer. Specific mechanisms include the reduction of the mucosal surface size for jejunal segments and the shifting in mucin secretion patterns for colonic segments.
In this report we have raised the question whether genotoxic carcinogens are more potent than nongenotoxic carcinogens when studied in long-term carcinogenicity assays in rodents. To build a large database of compounds for which both carcinogenicity and genotoxicity had been investigated, we have used a database produced by Gold and co-workers for carcinogenic potency data (975 chemicals) and a database produced by Würgler for genotoxicity data (2834 chemicals). Considering compounds positive or negative in at least three short-term tests and in at least 75% of available tests, we could define 67 genotoxic carcinogens and 46 nongenotoxic carcinogens. Carcinogenic potency of genotoxic carcinogens was about 50 times higher than carcinogenic potency of nongenotoxic carcinogens. Our results are different from the results of Tennant et al.; their database (24 genotoxic carcinogens and 12 nongenotoxic carcinogens compatible with our definition) seems to suggest that there is practically no difference in potency between genotoxic and nongenotoxic carcinogens. The two databases have only four compounds in common and are also different in terms of number of elements for different chemical classes. Nitrosocompounds, nitrogen mustards, hydrazine derivatives, and polycyclic aromatic hydrocarbons are not represented in the database of Tennant. The overall impression from our analysis is that the usefulness of short-term tests of genotoxicity could be significantly better than what has been suggested by the previous work of Tennant et al. because these tests tend to detect, at least for many important chemical classes, the most potent carcinogens. This consideration may not be valid for certain classes of chemicals.
The Interlab Project is a university-industry joint project recently funded by the Italian government as part of the improvement of the Italian research infrastructure; among its short-term goals are the implementation of data banks of biomedical interest and the spread of informatic tools for biomedical research. Results of both long-term assays of carcinogenicity in rodents and short-term in vitro and in vivo tests of genotoxicity are relevant for a wide body of users, ranging from carcinogenesis research laboratories to industries and governmental agencies. To evaluate the most appropriate ways of spreading information on these experiments, a detailed analysis on information recorded in available databases has been carried out. Furthermore, the contents of the most known databases have been compared, with respect to a specific compound, to evaluate both the overall reliability of these systems, compared to longer and more complex assessments carried out manually starting from bibliographic searches, and the level of concordance among them.
In this study we have compared the results of Scanning Electron Microscopy (SEM) with Light- and Stereomicroscopy in a series of small bowel biopsies in children. In 9 cases displaying features of partial or subtotal atrophy, Light and Dissecting-Microscopy yielded similar results. The distinction between coeliac and non-coeliac chronic diarrhoea was only possible on clinical grounds, and by the immunological detection of specific antibodies. On SEM however coeliac patients showed characteristic alterations consisting of: absence of villi; prominent crypt outlets resulting in a mosaic appearance; concentric furrows running all around the openings; and downy brush feature at high power. The microvilli were loosely distributed and had an irregular pleomorphic outline; they often displayed a drumstick swelling of the tip and were bent. In contrast, non-coeliac chronic diarrhoea cases were characterized by a thick mucous layer on the mucosal surface, that made it impossible to visualize further changes. Peculiar vascular changes in lymphangiectasia and in sickle beta thalassemia could be detected only by Light Microscopy. In addition, in the lymphangiectasia case SEM allowed the detection of enteroadherent bacteria; and in the lambliasis case, of pseudomembranes. Absence of glycocalyx was noted both in controls and in patients. The results of this study point to a diagnostic utility of SEM particularly in the differential diagnosis of chronic diarrhoea; moreover they suggest that enteroadherent bacteria may not be pathogenic and that the absence of glycocalyx is not specific for allergic enteropathy as previously claimed.
The present study was performed to evaluate the potential of glutaraldehyde-tanned mandril-grown grafts as caval substitutes. Short-term experiments consisted of 30 tubular grafts (35 x 8 mm), either of tanned collagen or polytetrafluoroethylene, that were sutured in the infrarenal inferior vena cava of pigs and removed 1 hour after implantation. There was no significant difference between the extent of the thrombus-lined graft surface in the biologic group and that in the polytetrafluoroethylene group. The amount of inner thrombus on tanned collagen grafts was significantly correlated to platelet activity. Long-term experiments involved 30 similar segments of both materials, which were sutured in the inferior vena cava and harvested 7, 14, 28, 56, and 112 days after operation. The 112-day patency rate of collagen grafts was 67%. The 56-day patency rate of polytetrafluoroethylene grafts was 16%. The difference was statistically significant (p less than 0.01). Collagen grafts were lined by a thin neointima (200 micron) in all but two cases. The neointima was completely endothelialized within 4 weeks from implantation. In conclusion, tanned collagen grafts may represent a suitable material for venous replacement.
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We have analyzed a significant number of studies existing in the literature, in which the ability of different short-term tests for predicting carcinogenicity in rodents was investigated. We have separated these studies into two groups. In the better known group of studies, qualitative predictivity was investigated (sensitivity and specificity). In the second group of studies (analyzed in greater detail), positive results were examined for the correlation between carcinogenic potency and potency of response in a given short-term test. There is substantial agreement between qualitative and quantitative predictivity; both appear to be situated between a low and moderate level. We have analyzed the interesting possibility of using the quantitative approach not only for positive data but for combined positive and negative data as well. We have stressed that short-term tests of genotoxicity should be asked to predict only initiation and irreversible alterations in the genome and not to predict a combination of these events, including promotion and modulation of differentiation. Even with regard to only initiation, genotoxicity data should be related to comparative metabolism, as well as to considerations of the significance of different end points and structure-activity relationship data. In conclusion, the information coming from short-term tests of genotoxicity is probably useful but should be used in conjunction with other types of information and only for predicting one particular class of events in the entire process of carcinogenesis.
A hundred strains of Saccharomyces cerevisiae were examined for the ability to produce higher alcohols. In the strains tested the production of higher alcohols was found to be an individual strain characteristic and, as such, was statistically significant. The characteristics of the strains used (flocculation ability, foaming ability, killer character, and non-H2S production) were found to be uncorrelated to isobutanol and isoamyl alcohol production, whereas the production of high levels of n-propanol was found to be related to inability to produce H2S. This, in turn, suggests a link to methionine biosynthesis.
Infectious complications are the highest risk in hematology. In this study, subclavian approach and tunnellization are reviewed. Four hundred (400) catheters were evaluated by the Isolator Culture method. Catheters are left in place a long time (mean time 30 days). Colonization occurs rarely (about 10.5%). In hematology, subclavian tunnelized catheter occurs to be a safe and reliable central venous catheter.
Organs' procurement oblige to take care of a great number of brain death patients. This study concerns the psychological influence of such a situation on teams, nurses and physicians of this specific activity of harvesting. It took place in three organs' procurement intensive care units and interested sixty three men and women. These teams reveal the difficulty to live "the brain death", according to brain death patients themselves and their families, but also to transplantation: to work on brain death patients for the life of other patients. So it seem necessary to give a place at a psychologist in this specific intensive care units not for the patients, they are dead, but for the teams.
With regard for the principles that govern the correct application of intramedullary osteosynthesis in the long bones of the lower limb, the authors also support its use in the humerus. After an exhaustive survey of the specific problems at this site, a critical review of 130 cases observed over the last 15 years is reported. Extremely favourable results emerged in the treatment of the humerus with this means of synthesis, thanks to its surgical, mechanical and biological advantages.
Intramedullary osteosynthesis with Küntscher nailing is an appropriate and extremely effective operation in the treatment of diaphyseal fractures of the ulna. Like the other long bones of the limbs (femur, humerus, tibia), in the ulna, as well, the advantages of the method, particularly when performed in closed surgery, are undeniable, so much so that this bone has a shape which is particularly favourable to nailing. The authors present and discuss their personal series of cases reporting results which are excellent. Thus, once again, the great reliability of this simple means of synthesis, in use for more than 20 years, is emphasised, and the subject is completed with a series of previous technical suggestions on how to obtain the best results.
PTA represents a slightly invasive method for treatment of iliac arteries stenoses. The Authors present their experience about this topic and discuss current indications in the use of this technique. They believe that beyond the already defined indications, such as treatment of short stenoses, transluminal angioplasty can be employed for long stenoses too, eventually combined with limited surgical procedures. They stress the importance of combining traditional PTA with new percutaneous or intraoperative Argon Laser technology, that surely will contribute to broad its indications and to improve its results.
Based on more than 20 years experience, the authors support the effectiveness of intramedullary nailing in the treatment of diaphyseal fractures of the femur. They review the history and advantages of this method and discuss the biomechanical principles on which it is based. Recent advances in technique have made it possible to secure proximal and distal anchorage in cancellous bone. This allows the method to be extended to more proximal and distal fractures than in the traditional method which is applicable only to the middle third. It also facilitates progressive axial compression, early loading and early mobilisation of the limb, thus creating the optimum biological conditions for consolidation and joint function. The closed method also reduces blood loss and the risk of infection. The techniques adopted to deal with more complex situations are described. These include moderately comminuted oblique and spiral fractures and certain bifocal fractures. Finally, the results of treating 450 cases are reviewed, with a longterm analysis of 198 patients.
The authors propose the association of two or more surgical methods in the treatment of aseptic pseudarthrosis of the tibia with the object of increasing the probability of union and reducing the period of disability. Based on the anatomo-pathological features of the pseudarthrosis, methods aimed at obtaining mechanical stability (fibula pro tibia, Küntscher) and methods which stimulate biological repair (decortication, transplants) are associated. The results obtained confirm the theoretical presuppositions, revealing a relatively short amount of time required for healing.