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R Modica

Publications and source records attributed to R Modica.

14 recordsLinked to original sources
PubMed1992

Non-innervated Merkel cells and Merkel-neurite complexes in human oral mucosa revealed using antiserum to protein gene product 9.5.

Merkel cells are non-keratinized cells present in many different epithelia, but whose origin and functional role are still controversial. They were here investigated by means of antisera to the neural and neuroendocrine markers protein gene product 9.5 (PGP 9.5), and neurone-specific enolase. The expression of both markers in Merkel cells of human gingival and palatal mucosa was confirmed. Merkel cell-neurite complexes and isolated non-innervated Merkel cells had a similar morphology when stained by either antiserum. Merkel-neurite complexes were clustered in relatively large numbers in the lingual gingiva, thus constituting structures closely similar to the 'touch domes' in the skin. Clusters of non-innervated cells showing the same immunohistochemical features as Merkel cells were also demonstrated. In other areas of the oral mucosa, the innervated and non-innervated elements were only occasionally seen but there were many encapsulated Meissner-like receptors. When comparing the two different antisera, anti-PGP 9.5 appeared to provide a more consistent labelling of small fibres inside the epithelium and of bulb-like terminals on Merkel cells.

Adolescent↗
PubMed1991

Inactivation of endothelin by polymorphonuclear leukocyte-derived lytic enzymes.

Cultured bovine aortic endothelial cells (BAEC) released endothelin-1 (ET-1) in the culture medium in a time-dependent fashion. Coincubation of fMLP-activated human polymorphonuclear leukocytes (PMN) with BAEC caused a fast (maximal activity was reached within 15 minutes) and cell number-dependent disappearance of ET-1 from the medium. This effect was direct to ET-1, because it was also present when PMN were incubated with the synthetic peptide in the absence of BAEC. PMN-dependent disappearance of ET-1 was associated with loss of constrictor activity on isolated rabbit aorta. PMN-released products were responsible for ET-1 degrading activity, because supernatants of activated PMN were equally effective as the intact cells. Resting PMN, in the same time frame, were uneffective. Eglin C, a potent blocker of PMN-derived elastase and cathepsin G, reversed the ET-1 inhibitory activity of fMLP-stimulated PMN and of their supernatant. Direct addition of elastase and cathepsin G to synthetic ET-1 destroyed its immunoreactivity and this effect was blocked by eglin C. High-performance liquid chromatography (HPLC) analysis supported the hypothesis that ET-1 degradation by PMN was due to enzymatic proteolysis. These data provide evidence that activated PMN are able to degrade ET-1 through the release of proteases. Because physiologic concentrations of PMN can destroy high amounts (up to 100 nmol/L) of ET-1 within a few minutes, we propose that this mechanism of ET-1 inactivation has biologic relevance.

Animals↗
PubMed1991

Accuracy and response time of a portable pulse oximeter. The Pulsox-7 with a finger probe.

We studied the performance of a portable pulse oximeter in 123 consecutive adult patients by spot-checking with a finger probe and by spectrophotometry of oxygen saturation on a simultaneous arterial blood sample. 88 patients were overtly hypoxemic (HbO2 less than 90%) and 26 showed severe hypoxemia (HbO2 36-70%). The differences between the two methods showed a skewed distribution with a positive tail due to the over-estimation of lower saturation values by the pulse oximeter. Overall, the 95% confidence interval for the median difference ranged from -0.6 to +0.5%. The limits of agreement (distribution-free 95% confidence interval for the sample) were -5.8 to +11.6%. Pulse oximetry can be recommended as a first assessment of the respiratory balance only if a cut-off value of HbO2 equal to 90% in nonsmoking, air-breathing subjects is acceptable. The finger probe implies a response delay of approximately 30 s, making the instrument rather insensitive to short hypoxemic transients. With a predictive value around 90%, the pulse oximeter may be a useful portable screening tool.

Adolescent↗
PubMed1990

The innervation of human teeth and gingival epithelium as revealed by means of an antiserum for protein gene product 9.5 (PGP 9.5).

The innervation of human teeth and oral mucosa has been studied in the past by different methods, none of which offered a clear description of the precise morphology of nerve fibers and terminals and of nerve organization as a whole. Recently, interesting findings have been obtained by means of immunohistochemical investigations for neurofilaments and S-100 proteins. A new brain-specific molecule, protein gene product 9.5 (PGP 9.5), has been used for the first time in the present research to investigate the distribution of nerves in human oral mucosa and decalcified teeth, about which there is a paucity of information. The data provided in this study, confirming previous work in other species, may be of value for understanding the anatomy of human oral innervation. In the oral mucosa, the antiserum labels nerve fibers, corpuscles, and neuroendocrine (Merkel) cells. In sections of decalcified teeth, numerous PGP 9.5 positive fibers are demonstrated in the pulp and in the inner 100 microns of dentin. The novel nerve tissue protein used, PGP 9.5, thus appears to be a reliable marker for studies of nerve fibers in human tissues and not to be affected by decalcification procedures. It could then be used for investigations on the innervation of normal and pathological calcified human tissues.

Dentin↗
PubMed1990

[Prevalence of cancer of the oral cavity and oropharynx].

A study was made to determine how prevalent oral and oropharyngeal cancer proved to be in 600 E.N.T. out-patients upon their initial examination. The aim was to ascertain which population was at high risk for thys type cancer through the use of computerized analysis of the risk factors. By scoring risk factors for oral and oropharyngeal cancer, subjects were classified into 3 risk classes: low, medium and high. Endoscopy proved positive in 22 cases only in the high risk class. Further diagnostic procedures, performed for all subjects, revealed 16 cases of squamous cell carcinoma, 1 'in situ' carcinoma, and 5 precancerous lesions of the oral cavity and oropharynx. This data is then discussed and the suggestion made that scoring such risk factors as tobacco and alcohol consumption could also be effective in identifying the high risk groups for this disease in a selective screening program.

Adult↗
PubMed1989

Erythrocyte adducin differential properties in the normotensive and hypertensive rats of the Milan strain. Characterization of spleen adducin m-RNA.

Previous studies have shown that erythrocytes from the Milan hypertensive strain of rats (MHS) differ from erythrocytes from the control normotensive strain (MNS). These differences are determined within the stem cells, are genetically associated with the development of hypertension, and are similar to those found between the tubular cells of the two strains. Moreover they seem to be dependent upon the presence of the membrane skeleton proteins. In this paper we describe our studies aimed at identifying some precise protein difference between the membrane skeletons of the two strains, which may cause the cellular differences described above. Milan hypertensive strain and MNS rats were immunized with ghost or membrane skeleton extracts prepared from the other or their own strains. Only MHS rats immunized with MNS ghost or membrane skeleton extracts produced an antibody against a 105 KD protein in about 95% of the animals. This protein has been identified with the recently described cytoskeletal protein adducin on the following bases: the protein binds calmodulin (CaM) and protein kinase C (PKc) in a Ca2+ dependent way. It also binds phosphatidylserine, is the substrate of exogenous PKc, and finally it is purified by high salt extraction of Triton-X100 insoluble erythrocyte cytoskeletons followed by affinity chromatography on CaM-sepharose. Using this antibody the isolation from a mouse spleen library, the characterization and sequencing of a partial cDNA clone coding for this protein has been carried out. In conclusion adducin may be considered a very useful tool to test the hypothesis that the cellular differences between MHS and MNS may be caused by a difference in a membrane skeleton protein.

Amino Acid Sequence↗
PubMed1989

[Polyamines in tumors of the oral cavity].

The polyamines putrescine, spermidine and spermine are essential for normal growth and differentiation and the activity of the enzymes participating in their synthesis and catabolism are markedly modified in actively proliferating cells in vitro and in vivo. In some neoplastic cells a good correlation is observed between polyamine concentration and histology, so that a potential usefulness as diagnostic and prognostic markers has been suggested. In the study of ornithine decarboxylase, S-adenosylmethionine decarboxylase and spermidine acetyltransferase activities and of polyamine concentration in tumors of the oral cavity we have shown a marked increase in the tumor cells. In the epulis the ratio spermidine/spermine is inverted, so that it could be useful in differentiating benign from malign tumors.

Adenosylmethionine Decarboxylase↗
PubMed1976

Importance of pharmacokinetic studies on cyclophosphamide (NSC-26271) in understanding its cytotoxic effect.

Pharmacokinetic studies on cyclophosphamide (CP) and its alkylating metabolites produced by hepatic biotransformation have been performed in vivo in animals and in vitro in the perfused liver. CP levels were determined by a gas-chromatographic method combined with mass-spectrometry, and production of alkylating metabolites was assayed by the 4-(4-nitrobenzyl)pyridine reaction for alkylating compounds. Differenes in serum drug levels between normal rats and rats bearing Walker 256 carcinosarcoma were observed in vivo and were confirmed by the liver-perfusion technique. Pharmacokinetic parameters and enzyme kinetic data both in normal and in tumor-bearing animals will be presented. The disappearance of CP and the corresponding formation of CP metabolites was significantly modified when (a) CP was given after previous treatment with a compound which alters its biotransformation (ie, phenobarbital, an inducer of microsomal metabolism), (b) CP was given after previous treatment with CP (which inhibits microsomal metablism), or (c) CP was given with competitive substrates of aldehyde oxidase or dehydrogenase (glyceraldehyde, chloral hydrate, and disulfiram). Results obtained in animals or in the perfused liver will be discussed. The significance of this modified CP metabolism in influencing its cytotoxic effect will be discussed and correlations between drug levels and activity will be presented.

Animals↗
PubMedDate not supplied

[Limitations in the opening of the mouth of an arthrogenic nature].

Mouth opening limitations of arthrogenous nature are subdivided according to a personal schedule into indirect and direct types. The former are brought on by occlusal alterations: these affect articular remodelling and may cause anatomical and functional changes of varying gravity in the temporo-mandibular joint with consequent limitations on opening movements. The latter are the consequence of various pathogenic agents (traumatic, neoplastic, inflammatory, degenerative) originating within the articular structures and developing therein, progressively limiting their function. Some significant personal cases are reported and on the basis of the series the aetiopathogenetic problems of the various forms are discussed, with emphasis on those which represent the basic criteria for therapy.

Adolescent↗
PubMedDate not supplied

[An evaluation of the postoperative stability of the dental arches following interventions for segmental osteotomy].

The study evaluates the long-term postsurgical stability of segmentary osteotomy and compares it to the orthodontic expansion of the jaw which is well known for its tendency to relapse following contraction. The study of the postsurgical changes of the transversal and longitudinal diameters of the dental arches and of the area covered was carried out in a group of 15 patients using rigorously standardised methods. Heterogeneous variations were observed and although there was a prevalent tendency towards contractions these were small in size and of minor clinical importance. Even if only major postsurgical changes were taken into account, usually following considerable expansion of the jaw, especially if associated with the jaw's advance, it is clear that there is a greater clinical stability in comparison to orthodontic expansions. This confirms the therapeutic value of segmentary osteotomy.

Adolescent↗
PubMedDate not supplied

[Reimplantation of a mandibular segment resected for the removal of a voluminous osteoma].

Total resection of the host bone for compact voluminous osteoma of the angle and ascending branch of the mandible was followed by immediate reinsertion of the unimpaired segment in its original site. Radiographical check-up 2 yrs later showed that the segment was notably atrophic and flattened, and looked like a long-standing iliac crest graft.

Aged↗
PubMedDate not supplied

[Treatment of follicular cysts of the mandible with reduction cystostomy].

A surgical technique is described for the treatment of a voluminous mandibular cyst whereby the contrasting need to preserve the vitality of the teeth whose apex was near the cyst wall and that of preventing marsupialisation due to the difficulty of providing continuous and effective postoperative care were met by cystotomy with reduction of the primary cyst to a small, periapical cyst. The operation was planned to take place in two stages, the idea being to secure radical removal of the remains of the cyst at a later date. An exploratory inspection after 14 months showed that a bone cavity of negligible size and with no sign of a wall was left. Two objectives were thus achieved: maintenance of the vitality of the teeth around the cyst; improved and spontaneous alignment of the teeth to facilitate and simplify complementary orthodontic management.

Child↗