Biomedical subjects

K Genovese

Publications and source records attributed to K Genovese.

5 recordsLinked to original sources

PubMed2004

Finite element analysis of a new customized composite post system for endodontically treated teeth.

This paper investigated the mechanical behavior of a new customized post system built up with a composite framework presently utilized for crowns, bridges, veneers and inlay/onlay dental restorations. The material has been shaped so to follow perfectly the profile of the root canal in order to take advantage of the better mechanical properties of composites with respect to metallic alloys commonly used for cast posts. The analysis has been carried out with 3D finite element models previously validated on the basis of experimental work. The new post system has been compared to a variety of restorations using either prefabricated or cast posts. The structural efficiency of the new restoration has been evaluated for an upper incisor under different loading conditions (mastication, bruxism, impact). Results prove that maximum stress values in restored teeth are rather insensitive to post types and materials. However, the new customized composite restoration allows to reduce significantly the stresses inside the dentinal regions where conservative clinical interventions are not possible.

Bite Force↗

PubMed1998

Lymphokine-augmented activation of avian heterophils.

Heterophils are important mediators of innate resistance in poultry, especially in young birds that have not yet developed an acquired immune response. Invasion of the intestinal mucosa by Salmonella spp. initiates the recruitment of large numbers of heterophils to the lamina propria. Thus, the heterophilic response can control, but not eliminate, bacterial numbers in the bird until development of acquired immunity. Unfortunately, chicks and turkey poults are highly susceptible to Salmonella infections during the first 4 d posthatch due to the functional immaturity of both the innate and acquired immune systems. We have previously shown that the administration of Salmonella enteritidis (SE)-immune lymphokines (ILK) into either 18-d-old developing embryos or day-of-hatch chicks and poults conferred increased resistance to SE organ invasion. In this review, we present evidence that the protection induced by ILK is mediated by vigorous recruitment and activation of heterophils. These activated heterophils migrate rapidly to the site of bacterial invasion where they phagocytize and kill the SE. Specifically, in vitro studies demonstrate an enhancement of functional activities of the heterophils including chemotaxis, adherence, phagocytosis, and bacterial killing. In addition, during the activation process, membrane expression of adhesion molecules rapidly changes from L-selectins to beta2 integrins (CB11b/CD18) on the cells that become activated. These results further demonstrate the validity of preventive activation in poultry to induce the migration of large numbers of activated phagocytic cells to the site of infection by a pathogenic organism. Importantly, this immunopotentiation of the inflammatory response by ILK, as described here, induces the functional maturation of heterophils during the first 4 d posthatch.

Animals↗

PubMed1998

Evaluation of oral, subcutaneous, and nasal administration of Salmonella enteritidis-immune lymphokines on the potentiation of a protective heterophilic inflammatory response to Salmonella enteritidis in day-old chickens.

We have previously reported that the prophylactic administration of factor(s) from T-cell supernatants derived from Salmonella enteritidis-immune chickens (ILK) have a favorable effect in controlling or eliminating salmonellosis in neonatal poultry. Experimentally, we have used the intraperitoneal injection as the standard method of administering ILK to neonatal poultry. However, this method is neither easy, practical, nor economical for the poultry industry. In the present study, we evaluated the effectiveness of oral (p.o.), intranasal (i.n.), and subcutaneous (s.c.) administration of ILK for ease of delivery, induction of protective resistance against Salmonella enteritidis (Se) organ invasion, and the ability to activate peripheral blood heterophils in day-old chickens. In the first experiments, delivery of ILK p.o., i.n., and s.c. significantly (P < 0.01) increased the resistance of day-old chickens to Se organ invasion. The level of protection was equivalent to that induced by the i.p. route. Administration of a comparable protein control (bovine serum albumin, BSA) by the 3 routes induced no protective effect against Se organ invasion. Likewise, a significant increase was found in the number of circulating heterophils within 4 h of administration of the ILK by all routes. In the 2nd experiment, the function of the heterophils from ILK-treated birds was compared with that of the control cells in adherence, chemotaxis, and phagocytosis assays. The heterophils from birds given ILK i.p., s.c., p.o., or i.n. had significantly (P < 0.01) increased functional activities when compared to the activities of the heterophils from the control birds. These studies indicate that the delivery of ILK either orally or parenterally, routes which can be used by the poultry industry, can confer protection to chickens against a localized enteric Se organ invasion by potentiating the systemic heterophilic innate response.

Administration, Intranasal↗

PubMed1998

Functional responses of neonatal chicken and turkey heterophils following stimulation by inflammatory agonists.

OBJECTIVE: To determine functional responses of neonatal chicken and turkey heterophils to various inflammatory agonists. ANIMALS: 100 one-day-old chickens and turkeys. PROCEDURE: Blood heterophils were isolated and stimulated for 30 minutes at 39 C with ionomycin, phorbol myristate acetate (PMA), opsonized zymosan (OZ), or formyl-methionyl-leucyl-phenylalanine (FMLP). Functional responses (shape change, adherence, phagocytosis, influx of intracellular calcium, and oxidative burst) of stimulated heterophils were measured and compared with responses of unstimulated (control) heterophils. RESULTS: Turkey and chicken heterophils did not respond to FMLP stimulation. Stimulation of chicken and turkey heterophils with ionomycin resulted in significant increases in adherence, percentage of cells with a shape change, phagocytosis, intracellular calcium concentration, and oxidative burst. Turkey heterophils did not respond to PMA stimulation, whereas stimulation of chicken heterophils with PMA resulted in significant increases in adherence, percentage of cells with a shape change, phagocytosis, and oxidative burst but not intracellular calcium concentration. Stimulation of chicken and turkey heterophils with OZ resulted in significant increases in oxidative burst. CONCLUSIONS: Mechanisms regulating initiation of heterophil activation in neonatal chicken and turkey heterophils are consistent with those described for heterophils isolated from mature birds. The biochemical and cytoskeletal systems of neonatal avian heterophils undergo functional alterations following stimulation with inflammatory agonists. CLINICAL RELEVANCE: Understanding heterophil activation and regulation should eventually lead to methods for controlling bacterial diseases in poultry.

Animals↗

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