Search PubMed⌕ Search

Biomedical subjects

M Esposito

Publications and source records attributed to M Esposito.

At least 91 records · Page 5Linked to original sources
PubMed1998

Integration of press-fit implants in cortical bone: a study on interface kinetics.

The early healing phase of hard tissue implants is important to their long-term success. Problems during this phase can result in a so-called primary biological failure. In 24 New Zealand white rabbits, the healing in cortical bone of noncoated TiAlV and cpTi cylinders and of TiAlV cylinders plasma-spray-coated with hydroxyapatite (HA) of fluorapatite (FA) was investigated histologically and histomorphometrically after 3, 7, 14, and 28 days. Histomorphometry consisted of bone contact measurements and the use of a new semi quantitative scoring system that discriminated various tissues in contact with the implant. The results demonstrated that the most important parameter in initial implant healing is the bone itself and not the characteristics of the implanted material. For all implants, healing was characterized by a sequence of hematoma formation, bone resorption, and new bone formation where the initial press-fit situation revealed more bone-implant contact than after 7 and 14 days. There were only minor differences between the implant types: the new bone formation directly on the implant surface was qualitatively histologically superior to the CaP-coated implants, but this could be confirmed with the scoring method only for the HA-coated implants. It is concluded that initial press-fit fixation in cortical bones is not an end situation; rather, what happens is that as a result of interface remodeling, early postoperatively implant integration in the bone will decrease temporarily prior to a subsequent phase of new bone formation.

Animals↗
PubMed1998

A possible role of the plasmalemmal cytoskeleton, nitric oxide synthase, and innervation in infantile hypertrophic pyloric stenosis. A confocal laser scanning microscopic study.

In reference to a possible neuropathy in the pathogenesis of infantile hypertrophic pyloric stenosis (IHPS), previous studies have described alterations in peptidergic transmission while others have recently attributed an important role to nitrinergic activity. Little attention has been given to the organization of the extracellular matrix (ECM) and the constituent cytoskeleton and subsarcolemma of the pyloric smooth-muscle cell. To study a possible relationship between neuronal and muscular elements in IHPS, 9 biopsies from patients with IHPS and 5 biopsies of normal pylorus were examined using immunohistochemical techniques with regard to the distribution of nerve cells and fibers (bNOS and PGP 9.5) and the ECM (laminin) and cytoskeleton (talin, vinculin, dystrophin, alpha-smooth iso-actin, desmin) components of the pyloric muscle. Our results showed anti-protein gene product 9.5 and b-nitric oxide synthase immunoreaction respectively reduced or absent in nerve fibers with a positive reaction inside the ganglion cells. An uneven distribution of the ECM component laminin was evident, together with a negative immunoreaction to talin and dystrophin. The imunolocalization of vinculin, alpha-smooth iso-actin, and desmin was similar to the controls. Our findings suggest that there is a close relationship between the nerve and muscle elements in the pathophysiology of IHPS and that non-alteration of some elements of cytoskeleton organization can play an important role in regaining pyloric function after pyloromyotomy.

Cytoskeletal Proteins↗
PubMed1998

Use of automated solid-phase extraction equipment for the determination of ivermectin residues in animal liver by HPLC.

An improvement of the method commonly used for the determination of ivermectin is proposed. An automatic system is used for the solid-phase extraction column purification stage in order to provide more efficient and fast sample preparation, prior to separation and quantification by HPLC. Some tests were performed to obtain recovery and repeatability data. The mean recovery for spiked samples (five replicates twice at three concentration levels) was more than 90% in the concentration range 7.5-30 ng g-1. The tests for accuracy (five replicates at three concentration levels) gave a standard error of -2.0% at the highest and -19.2% at the lowest concentration. Concerning repeatability data (five replicates twice at three concentration levels), in the concentration range 7.5-30 ng g-1 the RSD varied from 9.29 to 2.15%. The described method was used in a survey on the presence of ivermectin in food-producing animals in two regions of southern Italy; no positives out of 250 liver samples were found.

Animals↗
PubMed1998

Biological factors contributing to failures of osseointegrated oral implants. (I). Success criteria and epidemiology.

The aim of this review was to offer a critical evaluation of the literature and to provide the clinician with scientifically-based diagnostic criteria for monitoring the implant condition. The review presents the current opinions on definitions of osseointegration and implant failure. Further, distinctions between failed and failing implants are discussed together with the presently used parameters to assess the implant status. Radiographic examinations together with implant mobility tests seem to be the most reliable parameters in the assessment of the prognosis for osseointegrated implants. On the basis of 73 published articles, the rates of early and late failures of Brånemark implants, used in various anatomical locations and clinical situations, were analyzed using a metanalytic approach. Biologically related implant failures calculated on a sample of 2,812 implants were relatively rare: 7.7% over a 5-year period (bone graft excluded). The predictability of implant treatment was remarkable, particularly for partially edentulous patients, who showed failure rates about half those of totally edentulous subjects. Our analysis also confirmed (for both early and late failures) the general trend of maxillas, having almost 3 times more implant losses than mandibles, with the exception of the partially edentulous situation which displayed similar failure rates both in upper and lower jaws. Surgical trauma together with anatomical conditions are believed to be the most important etiological factors for early implant losses (3.60% of 16,935 implants). The low prevalence of failures attributable to peri-implantitis found in the literature together with the fact that, in general, partially edentulous patients have less resorbed jaws, speak in favour of jaw volume, bone quality, and overload as the three major determinants for late implant failures in the Brånemark system. Conversely, the ITI system seemed to be characterized by a higher prevalence of losses due to peri-implantitis. These differences may be attributed to the different implant designs and surface characteristics. On the basis of the published literature, there appears to be a number of scientific issues which are yet not fully understood. Therefore, it is concluded that further clinical follow-up and retrieval studies are required in order to achieve a better understanding of the mechanisms for failure of osseointegrated implants.

Alveolar Bone Loss↗
PubMed1998

Biological factors contributing to failures of osseointegrated oral implants. (II). Etiopathogenesis.

The aim of the present review is to evaluate the English language literature regarding factors associated with the loss of oral implants. An evidence-based format in conjunction, when possible, with a meta-analytic approach is used. The review identifies the following factors to be associated with biological failures of oral implants: medical status of the patient, smoking, bone quality, bone grafting, irradiation therapy, parafunctions, operator experience, degree of surgical trauma, bacterial contamination, lack of preoperative antibiotics, immediate loading, nonsubmerged procedure, number of implants supporting a prosthesis, implant surface characteristics and design. Excessive surgical trauma together with an impaired healing ability, premature loading and infection are likely to be the most common causes of early implant losses. Whereas progressive chronic marginal infection (peri-implantitis) and overload in conjunction with the host characteristics are the major etiological agents causing late failures. Furthermore, it appears that implant surface properties (roughness and type of coating) may influence the failure pattern. Various surface properties may therefore be indicated for different anatomical and host conditions. Finally, the histopathology of implant losses is described and discussed in relation to the clinical findings.

Animals↗
PubMed1998

Combination of cisplatin-procaine complex DPR with anticancer drugs increases cytotoxicity against ovarian cancer cell lines.

DPR, cis-diamminechloro-[2-(diethylamino)ethyl 4-amino-benzoate, N4]-chlorideplatinum(II) monohydrochloride monohydrate, is a newly developed water-soluble platinum compound which possess minimal cross-resistance to cisplatin and shows relatively less side effects. In an attempt to establish whether the combination of DPR with other conventional anticancer drugs would be of any benefit we assessed in vitro the cytotoxic effects of combinations of DPR with the antimetabolites 5-fluorouracil (5-FU) and methotrexate (MTX), the alkylating agents mitomycin C (MMC) and cisplatin, the antimicrotubule agent taxol (TAX), and the intercalating agent of the anthracycline group doxorubicin (DOX) on murine M5076 ovarian reticulosarcoma and human A2780 ovarian carcinoma cells. These agents were selected because of their common use in the clinic and because they represent four distinct categories of antineoplastic mechanisms. Cells were incubated for 72 h in the presence of single or combined drugs, and the cytotoxic effect was determined by the MTT assay. The analysis of combination treatment was made by the isobole method. In human A2780 cells, an overall synergy was found for DPR combined with 5-FU, DOX and cisplatin. Synergistic effects were also observed for most combinations with MTX or MMC. A DPR concentration-dependent additivity and antagonism was seen at the highest MTX concentration (1 microM), while additive effects were observed for the combined treatments of DPR and low concentrations of MMC (0.008 and 0.0016 microM). Additive effects were also observed for the association of DPR and TAX over most combinations tested. In murine M5076 cells, synergism was the prevailing result observed when DPR was combined with 5-FU, DOX, MMC or cisplatin. When administered together with MTX we observed additivity over most combinations tested. These findings suggest that DPR, when simultaneously administered with standard anticancer agents, may be advantagious for cytokilling.

Antibiotics, Antineoplastic↗
PubMed1998

Neurotoxic effect of cisplatin and the cisplatin-procaine complex DPR studied in organotypic cultures of chick embryonic dorsal root ganglia.

Neurotoxic effects of cisplatin and the cisplatin-procaine complex cis-diaminechloro-[2-(diethylamino)ethyl 4-aminobenzoate, N4]-chlorideplatinum(II) monohydrochloride monohydrate (DPR) were compared in organotypic cultures of chick embryonic dorsal root ganglia maintained in a semi-solid (soft agar) culture medium. The changes of two characteristics of the neurite outgrowth, the mean radial length of neuritic processes growing out from the ganglia and the area of neurite outgrowth around the ganglion, were used as parameters to evaluate the toxic effect of both compounds. The drugs were administered to the cultures at concentrations ranging from 13 to 120 microM. The half-maximum inhibition concentration (IC50) was determined from the concentration-response curves for both the mean radial length of neurites and the area of neurite outgrowth. An analysis of these parameters revealed that DPR was significantly less neurotoxic than cisplatin. In fact, considering the mean radial length of neurite processes, the IC50s of cisplatin were 56, 65 and 66 microM after 24, 48 and 72 h of exposure, respectively. By contrast, for DPR the IC50s were 116 microM after 24 h, and greater than 120 microM after 48 and 72 h of exposure. When we considered the area index (i.e. the area of neurite outgrowth normalized for the area of the ganglia), the IC50s for cisplatin were 41, 52 and 55 microM after 24, 48 and 72 h of exposure, respectively, whereas for DPR the IC50s were 59 microM after 24 h, and greater than 120 microM after 48 and 72 h of exposure. Our results support previous findings of lower toxicity of DPR to non-neoplastic tissues, as compared to cisplatin.

Animals↗
PubMed1998

Clenbuterol residues in non-liver containing meat as a cause of collective food poisoning.

beta 2-adrenergic agonists, particularly clenbuterol, are illegally used as growth promoters to obtain lean in meat. Their administration in feedlots can constitute a severe risk for animal welfare and exposes consumers to involuntary drug consumption at pharmacological active concentrations. Reported poisoning episodes have been associated with the consumption of beef liver where clenbuterol residues concentrate. In August 1996, 62 persons asked for medical help at the emergency rooms of 2 hospitals near the city of Caserta (Italy). Their clinical profile was characteristic of previously occurring clenbuterol intoxication, which reported superventricular extrasystoles and atrial fibrillation. All patients had non-liver beef meat consumption 10-30 min to 2-3 h before symptoms developed. An ELISA screening test specific for clenbuterol confirmed the drug's presence. Definitive confirmation of clenbuterol and determination of the drug content in meat samples were obtained by GC-MS, using 2 different derivatization. Concentrations in the meats ranged from 0.8 to 7.4 mg/kg. These analytical data provided evidence of the seriousness of the poisoning and helped the National Health System identify other possible misinterpreted cases. This case demonstrates that clenbuterol poisoning can also occur after consumption of beef meat other than liver.

Adolescent↗
PubMed1998

[The correlation between Doppler echography with a contrast medium and CT in the study of a hepatocarcinoma submitted to chemoembolization].

PURPOSE: We report our preliminary experience concerning Doppler studies with the intravenous injection of a galactose-based echo contrast agent (SHU 508 A) in hepatocellular carcinomas (HCCs) treated with transcatheter arterial chemoembolization. We correlated US findings with those of iodized-oil helical CT. MATERIAL AND METHODS: In 1997 we examined 18 patients with cirrhosis and HCC (31 nodules in all) submitted to hepatic oily chemoembolization 15-30 days earlier. The lesions were studied with color and power Doppler US before and after echo contrast agent infusion (300 mg/mL, injection/nodule, constant rate in 60-90 s) and with Lipiodol CT (0-7 days after US). In the retrospective analysis, special care was paid to Doppler signals from pulsatile intra- and perinodular flow and to the detection of new small vessels on enhanced images. The signal was graded as absent (0), weak (1), medium (2) and strong (3). The oily agent uptake on CT images was graded as absent (0), grade I (< 10%), II (< 50%), III (> 50%) and homogeneous (IV). All scores were given on a blind basis. RESULTS: Liver enhancement was found in all cases and always lasted long enough to allow the accurate depiction of parenchymal lesions (at least 8 minutes). Signal intensity could be evaluated in 27 of 31 HCCs (2 were too deeply seated and two were too affected by cardiac activity). We had the following scores: basal color Doppler: grade 0 = 15 lesions, grade 1 = 8 lesions, grade 2 = 4 lesions; contrast-enhanced color Doppler: grade 0 = 11 lesions, grade 1 = 7 lesions, grade 2 = 8 lesions, grade 3 = 1 lesion; basal power Doppler: grade 0 = 12 lesions, grade 1 = 8 lesions, grade 2 = 6 lesions, grade 3 = 1 lesion; contrast-enhanced power Doppler: grade 0 = 10 lesions, grade 1 = 7 lesions, grade 2 = 8 lesions, grade 3 = 2 lesions; Lipiodol-CT: grade 0 = 1 lesion, grade I = 1 lesion, grade II = 7 lesions, grade III = 8 lesions, grade IV = 10 lesions. The difference between color and power Doppler scores, both compared to each other and between basal and enhanced images, never exceeded one. CONCLUSIONS: Contrast-enhanced Doppler US is a simple and fast technique allowing strong, constant and long-lasting enhancement. Doppler US techniques permit the effective and realistic study of HCC nodules treated with chemoembolization and show a better correlation with Lipiodol CT than basal studies. Power Doppler is slightly more sensitive and accurate than color Doppler and shows a better correlation with Lipiodol CT.

Adult↗
PubMed1998

[The role of imaging diagnosis in the study of intestinal infarct].

Acute mesenteric insufficiency is a surgical emergency with a difficult methodological approach. Its high mortality is mainly due to delay in the correct diagnosis. In turn, this is due to the lack of specificity, specially in the early-middle phase, of the clinical presentation, laboratory data, and plain abdominal radiographic findings. In front of this uncertainty, some authors advocated an "aggressive" approach with early use of angiography (nevertheless at risk of a high rate of negative examinations), other remained on more wait-and-see or fatalist positions, and other evaluated the possible diagnostic impact of noninvasive methods alternative to angiography. With the purpose of a correct employment from the surgeon of the various diagnostic tools actually available, we illustrated in this review the possibilities and limitations of the methods proposed in the evaluation of bowel infarction: plain abdominal radiography, gastrointestinal tract contrast studies, angiography, sonography, computed tomography (CT), magnetic resonance imaging (MRI).

Angiography↗
PubMed1997

Suramin/epidoxorubicin association in hormone-refractory prostate cancer: preliminary results of a pilot phase II study.

PURPOSE: Previous studies indicate that suramin may be an active agent for treating hormone-refractory prostate cancer. However, antitumour responses were observed in initial experiments only when plasma suramin concentrations were maintained in excess of 250 micrograms/ml. Dose-limiting toxicity, especially neurological toxicity, is directly related to the duration of exposure and sustained plasma drug concentrations of 300 micrograms/ml or more. Combination with other agents such as epidoxorubicin, a drug with demonstrable activity in metastatic prostatic carcinoma, could be more effective and allow reduced suramin doses, while maintaining the suramin antitumor effect; this could make suramin therapy more feasible. On the basis of preclinical synergistic activity for combined suramin/doxorubicin in prostate cancer cell lines, a pilot study in patients with metastatic hormone refractory prostate cancer was performed. MATERIALS AND METHODS: Ten patients with hormone-refractory prostate cancer received a fixed dosing scheme of suramin infusion in combination with weekly epidoxorubicin at 25 mg/m2. Therapy was discontinued for dose-limiting toxicity or progressive disease. RESULTS: None of the ten patients achieved a prostate-specific antigen reduction of more than 50% and no objective responses were observed in any patient. Dose-limiting toxicity was observed in four patients: grade 3 neurotoxicity was observed in three patients and grade 3 nephrotoxicity in one patient. CONCLUSIONS: Suramin/epidoxorubicin association, despite the encouraging preclinical results, was not able to improve the antitumour activity of suramin and showed significant toxicity. The results achieved in our study, although in a small number of patients, seem to suggest that this regimen cannot be recommended for use in the treatment of metastatic hormone-refractory prostate cancer.

Adenocarcinoma↗
PubMed1997

Carboplatin and cisplatin pharmacokinetics after intrapleural combination treatment in patients with malignant pleural effusion.

BACKGROUND: Cisplatin (DDP) and carboplatin (CBDCA) are two of the most effective drugs in a locoregional approach. Since simultaneous combined treatment with intrapleural DDP and CBDCA has not been reported in humans, we investigated its use in patients with malignant effusions, focusing on pharmacokinetics. PATIENTS AND METHODS: The pharmacokinetics of DDP and CBDCA were studied in 10 patients with malignant pleural effusion treated intrapleurally with a combination of DDP (60 mg/m2) and CBDCA (270 mg/m2) and in additional patients who received the same doses of drugs administered intravenously as single agents or in combination. Platinum (Pt) species originating from DDP (metabolites plus unchanged DDP) and intact CBDCA in plasma and pleural fluid ultrafiltrates were measured by means of high performance liquid chromatography and atomic absorption spectrometry. RESULTS: Both in the plasma and pleural fluid, the total levels of free Pt represented the additive result of the individual concentrations of CBDCA and Pt-species derived from DDP. After intrapleural combination, high pleural-plasma ratios of the peak concentrations and AUCs were observed both for CBDCA and DDP-derived Pt species, highlighting a distinct local pharmacological advantage. However, the Pt species originating from DDP were absorbed more rapidly from the pleural cavity than CBDCA (Ka = 86 x 10(-3) vs. 37 x 10(-3) min-1, P < 0.05). Intrapleural combination of CBDCA and DDP produced therapeutic plasma levels of reactive (free) DDP species and increased the extent of their residence time (MRT) compared with single intravenous DDP treatment [peak concentration: 1.1 +/- 0.1 (SD) vs. 1.6 +/- 0.2 microgram/ml; MRT: 5.2 +/- 1.9 vs. 0.5 +/- 0.06 h]. Furthermore, the plasma AUC of free CBDCA after intrapleural combined treatment (2.1 +/- 0.5 mg/ ml x min) was similar to that after intravenous administration of CBDCA alone (2.1 +/- 0.2 mg/ml x min). The intrapleural treatment was well tolerated by all patients. Toxicity consisted of mild nausea and vomiting (grade 1-2 according to the WHO scale) in four patients. Myelosuppression (grade 1-2) was remarkable only in two heavily pretreated patients. No evidence of recurrence of the pleural effusion was observed in six patients (complete response), while an asymptomatic minimal fluid reaccumulation not requiring drainage (partial response) was observed in four patients. CONCLUSIONS: The pharmacologic results seem to exclude a pharmacokinetic interaction between CBDCA and DDP and suggest that a dose of CBDCA 2-fold higher than that used in this study associated intrapleurally with 60 mg/m2 DDP could induce an acceptable and predictable myelosuppression.

Aged↗
PubMed1997

Failure patterns of four osseointegrated oral implant systems.

The aim of this metanalysis was to investigate possible differences in failure patterns among four different osseointegrated oral implant systems. Only systems with a supposed scientific validation, based on long-term follow-up studies, were selected for this analysis, i.e. the Brånemark system, the Calcitek Integral system, the Interpore IMZ system and the Straumann ITI system. While several prospective reports could be found on the Brånemark system, only a few retrospective investigations concerning the ITI and the IMZ systems were available. No data on the Integral system could be employed. Despite these limitations, a substantial difference in failure patterns among various implant systems was observed. The Brånemark implants showed a higher incidence of early failures, though sharply decreasing over time. On the contrary, IMZ implant characterized by rougher surfaces displayed a lower incidence of early failures, but showed constant or increased failure rates over time. For the ITI implants, for example, a higher prevalence of late failures, attributable to chronic bacterial infection (peri-implantitis), was observed when compared to the Brånemark system. With the exception of the latter implant system, prospective long-term follow-up studies, using similar and well-defined success criteria, are needed for the others to confirm the current preliminary findings.

Journal Article↗
PubMed1997

Immunohistochemistry of soft tissues surrounding late failures of Brånemark implants.

The objective of the present investigation was to characterize the cellular composition of the soft tissues surrounding consecutively retrieved late failures of Brånemark implants. Criteria for implant failure were signs of loss of osseointegration (radiographic peri-fixtural radiolucency and mobility). The clinical history of the implants did not include adverse symptoms. At the time of retrieval, percussion-induced pain was experienced at 4/8 implants, but no macroscopical signs of inflammation or infection or infection was observed. Immunohistochemistry was applied on 6 marginal peri-implant specimens and on specimens of deeper tissues associated with the previously load-bearing implant surface from 8 failed implants, whereas 6 clinically healthy mucosal specimens and 4 hyperplastic biopsies from stable implants served as controls. The immunohistochemical evaluation showed that the soft tissues surrounding failed implants contained a large number of macrophages (CD68), HLA-DR positive cells, lymphocytes and plasma cells preferentially accumulated towards the removed implant surface. PMNs were a rare finding. Downgrowth of epithelium, in some cases encapsulating the whole fixture, was observed in sections where an intact implant/soft tissue interface was preserved. Healthy control mucosal specimens always contained labelled cells, albeit in a low amount, whereas hyperplastic control samples displayed an intense inflammatory and immunological response with numerous positive cells and PMNs scattered throughout the biopsy. In conclusion, failed implants were characterized by a chronic inflammatory response of the surrounding tissues with macrophages as the predominant labelled cell type, while hyperplastic tissues around stable implants were distinguished by an acute inflammatory process. These findings suggest that an on-going infection is unlikely to be the etiological factor for the late failures of dental implants examined in this study.

Aged↗
PubMed1997

High-dose mitoxantrone with peripheral blood progenitor cell rescue: toxicity, pharmacokinetics and implications for dosage and schedule.

The optimal use of mitoxantrone (NOV) in the high-dose range requires elucidation of its maximum tolerated dose with peripheral blood progenitor cell (PBPC) support and the time interval needed between drug administration and PBPC reinfusion in order to avoid graft toxicity. The aims of this study were: (1) to verify the feasibility and haematological toxicity of escalating NOV up to 90 mg m(-2) with PBPC support; and (2) to verify the safeness of a short (96 h) interval between NOV administration and PBPC reinfusion. Three cohorts of ten patients with breast cancer (BC) or non-Hodgkin's lymphoma (NHL) received escalating doses of NOV, 60, 75 and 90 mg m(-2) plus melphalan (L-PAM), 140-180 mg m(-2), with PBPC rescue 96 h after NOV. Haematological toxicity was evaluated daily (WHO criteria). NOV plasma pharmacokinetics was also evaluated, as well as NOV cytotoxicity against PBPCs. Haematological recovery was rapid and complete at each NOV dose level without statistically significant differences, and there were no major toxicities. NOV plasma concentrations at the time of PBPC reinfusion were below the toxicity threshold against haemopoietic progenitors. It is concluded that, when adequately supported with PBPCs, NOV can be escalated up to 90 mg m(-2) with acceptable haematological toxicity. PBPCs can be safely reinfused as early as 96 h after NOV administration.

Antineoplastic Agents↗