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Biomedical subjects

M De Luca

Publications and source records attributed to M De Luca.

At least 73 records · Page 4Linked to original sources
PubMed1998

Expanded polytetrafluoroethylene and dental rubber dam barrier membranes in the treatment of periodontal intrabony defects. A comparative clinical trial.

As observed in previous case reports, dental rubber dam (DRD) can be utilized as a barrier membrane in the guided tissue regeneration (GTR) technique for the treatment of periodontal intrabony defects. The purpose of the present study was (1) to confirm the validity of DRD as a suitable material in regenerative procedures and (2) to compare, in a split-mouth clinical trial, the effectiveness of DRD-made membranes in the treatment of periodontal intrabony defects versus that of expanded polytetrafluoroethylene (e-PTFE) barriers. 22 systemically healthy non-smoker adult periodontitis patients (7 male, 15 female) aged between 35 to 58 years were selected for the study. In each patient, a couple of 2-3 wall intrabony defects, located in different quadrants, were treated by a GTR technique using DRD (test sites) and e-PTFE (control sites), respectively. Performing a strict control of the oral hygiene level and of the marginal gingival health during the whole period of study, clinical (pocket probing depth, PPD; probing attachment level, PAL; gingival recession, GR) and intrasurgical (depth of the defect's intraosseous component, IOC; level of the alveolar crest, ACL) parameters were recorded at baseline and at the 1-year re-entry procedure in each experimental site. Furthermore, the coronal level of the newly formed tissue from the base of the defect (NFTL) and the vertical bone gain (VBG) were calculated at the time of membrane removal and after the re-entry procedure respectively. Membranes were removed from both test and control sites after 5 weeks; however, exposure of the membrane always occurred in test sites whereas it was observed in only 6 out of 22 control sites, this fact leading to an incomplete coverage of the regenerated tissue by the gingival flap in 18 out of 22 test sites. In both test and control sites, a statistically significant improvement of clinical and intrasurgical parameters occurred at the end of the study period; however, a significantly greater improvement was observed in control sites for PAL (+4.0 mm versus +3.0 mm; p<0.05) and VBG (3.9 mm versus 2.9 mm; p<0.05) although at the time of membrane removal, NFTL was similar between the experimental sites (test: 5.8; control: 5.6; p>0.05). Conversely, test sites exhibited a statistically significant greater increase in gingival recession (+1.9 versus +1.2; p<0.05) and alveolar crest resorption (-1.1 versus -0.3, p<0.01) in comparison to controls. It was concluded that (1) DRD is a suitable material to be used as a barrier membrane in GTR procedures although (2) e-PTFE membranes can provide a greater improvement in PAL and VBG, probably because of the difficulty in completely covering the regenerated tissue due to the fact that the gingival tissues have undergone a consistent recession in DRD-treated sites. Further studies are needed to demonstrate if an adequate coverage of the regenerated tissue in DRD-treated sites can eliminate these differences.

Adult↗
PubMed1998

Two years of practice in adjustable silicone gastric banding (LAP-BAND): evaluation of variations of body mass index, percentage ideal body weight and percentage excess body weight.

BACKGROUND: In the treatment of morbid obesity, surgery had been the only method of obtaining a good and enduring weight loss. Although the procedure of choice is still a matter of debate, among gastric restriction procedures LAP-BAND has become our first choice. METHODS: We report the results from 62 morbidly obese patients operated in the period October 1994-December 1996. Their characteristics were: mean age 35.6 years, mean body weight 130.6 kg, mean height 162.3 cm, mean body mass index (BMI) 49.9 kg/m2, mean percentage ideal body weight (%IBW) 215.7 and mean excess weight (EW) 69.57 kg. RESULTS: Twenty-four months after surgery we found a mean BMI of 39.3, a mean %IBW of 168.6 and a mean % EW loss of 88.5. We removed the band in two patients: one after 9 months because of stoma stenosis and pouch enlargement in a woman who had been lost at follow-up, and the other for gastric slippage occurring after 18 months due to incorrect fixation of the band. CONCLUSION: Our results led us to consider LAP-BAND as the surgical approach for severe obesity among those patients selected for gastric restriction; indeed, it was very safe as well as effective and was rarely followed by complications.

Adolescent↗
PubMed1998

Efficacy of high dose of recombinant alpha 2b interferon on long term response in chronic hepatitis C and cirrhosis: prospective randomized multicentre study.

BACKGROUND/AIMS: The long-term response to alpha-Interferon in HCV-related chronic liver diseases is disappointing. A randomized controlled trial was conducted to investigate: 1) if doubling the standard regimen of 3 MU recombinant alpha 2b-interferon thrice weekly for one year could improve the long-term response, and 2) the efficacy of these two schedules in cirrhotic patients. PATIENTS AND METHODS: A series of 80 anti-HCV positive patients with biopsy proven liver disease (52 chronic hepatitis and 28 cirrhosis) were randomized to receive either 3 MU or 6 MU alpha 2b-interferon. RESULTS: Based on "intention-to-treat analysis", 38% in the 3 MU group and 53% in the 6 MU group had end-of-treatment response. After 24 months, 18% had long-term response: 5% in 3 MU group and 30% in 6 MU group (p < 0.008). HCV genotype had no influence on the response rate. Thirty-eight percent of the cirrhotics treated with 6 MU had long-term response, while none of those treated with 3 MU had long-term response (difference 38%; 95% confidence internal 10%-67%; p = 0.03). At the end of treatment, 38% of patients lost HCV-RNA. After 24 months only 19% remained HCV-RNA negative: 12 patients (31%) in the 6 MU group and 2 (6%) in the 3 MU group (p < 0.05). CONCLUSIONS: 6 MU of alpha 2b-interferon thrice weekly for 12 months is significantly better than 3 MU in inducing a long-term response and permanent loss of HCV-RNA. This result is particularly striking in the subgroup of cirrhotics.

Adult↗
PubMed1998

The effect of food and an antacid on the bioavailability of dexketoprofen trometamol.

This randomized three-way, crossover pharmacokinetic study was performed to determine whether food or an antacid alters the bioavailability of dexketoprofen trometamol. A total of 24 healthy volunteers received three single 25 mg doses of dexketoprofen trometamol administered either in fasting condition, after an antacid (Maalox), or after a high-fat breakfast. Each volunteer received the three treatments in a randomized order, with a 7-day washout period between treatments. Blood samples were taken at regular intervals up to 24 h after dose. Plasma dexketoprofen concentrotions were determined by HPLC and the main outcome measures were area under curve of concentration vs. time (AUC0-infinity), maximal plasma concentration (Cmax), and time to reach maximal concentration (t(max)). Administration of an antacid 10 min before dexketoprofen trometamol had no clinically relevant effect on any of the pharmacokinetic parameters. Food did not alter the extent of absorption of dexketoprofen trometamol, but t(max) was significantly increased and C(max). significantly decreased compared with the fasting state. In conclusion, we can state that neither antacid nor food has a significant effect on the overall bioavailability of dexketoprofen trometamol.

Adolescent↗
PubMed1998

Clinical comparison of dexketoprofen trometamol, ketoprofen, and placebo in postoperative dental pain.

The efficacy and tolerability of single doses of dexketoprofen trometamol 12.5 mg, 25 mg, and 50 mg and ketoprofen 50 mg were compared in this double-blind, randomized, placebo-controlled study of 210 patients with moderate to severe pain after removal of one mandibular impacted third molar tooth. Pain intensity and pain relief were monitored for 6 h after administration of medication using visual analogue and verbal rating scales. All four active treatments were significantly more effective than placebo (P < 0.001). Dexketoprofen 25 mg and 50 mg produced an analgesic effect within 30 min of administration and their effect persisted for 6 h. Ketoprofen 50 mg produced a level of analgesia similar to those of the higher doses of dexketoprofen trometamol, but it had a slower onset. The 12.5-mg dose of dexketoprofen trometamol was significantly superior to placebo but produced a lower level and shorter duration of analgesia compared to the other active treatments. There were no significant differences between 25 and 50 mg of dexketoprofen trometamol in any measure of analgesic efficacy. No serious adverse events were observed and there were no significant differences in the incidence of adverse events among treatment groups. These results demonstrate that dexketoprofen trometamol 25 mg is at least as effective as the racemic ketoprofen 50 mg in the treatment of postsurgical dental pain. The more rapid onset of action compared to ketoprofen suggests that dexketoprofen trometamol is more appropriate for treatment of acute pain.

Adult↗
PubMed1997

Topography and biological role of integrins in human skin.

We report the topography of integrins in the human epidermis and in cultured human keratinocytes. Both in situ and in vitro beta 1 integrins are exposed at the cell-cell adhesion interface while beta 4 is located on the basal membrane in contact with the basal lamina. Such defined sorting identifies discrete cell membrane domains that may be involved in defining, building up, and maintaining epithelial cell polarity. The distribution of integrins is deeply altered in hyperproliferative states like those occurring in several experimental conditions and in epidermal diseases.

Basement Membrane↗
PubMed1997

Developmental surface dyslexia is not associated with deficits in the transient visual system.

Deficits of the transient visual system have been reported in unselected groups of dyslexics. The aim of this study was to examine whether this finding holds when subjects with a specific type of developmental reading disorder (surface dyslexia) are considered. Ten Italian children were examined. They all presented the characteristic markers of surface dyslexia: slow and laborious reading with errors in tasks which cannot be solved with a grapheme-phoneme conversion (i.e., homophones). Contrast sensitivity thresholds to phase-reversal gratings were within normal limits for most subjects both for stimuli presented centrally and in the right parafovea. This indicates that developmental surface dyslexia is not associated with a deficit in the transient system. In contrast, sensitivity to high spatial frequency stationary stimuli was reduced.

Adolescent↗
PubMed1997

Long-term restoration of damaged corneal surfaces with autologous cultivated corneal epithelium.

BACKGROUND: Complete loss of the corneal-limbal epithelium leads to re-epithelialisation by bulbar conjunctival cells. Since conjunctival and corneal-limbal epithelial cells represent two different cell lines, this conjunctival healing of the cornea is followed by stromal scarring, decreased visual acuity, and severe discomfort. Unilateral corneal-limbal epithelial defects can be resolved by the transplantation of limbal grafts taken from the uninjured eye. However, this procedure requires a large limbal graft to be taken from the healthy eye, and is not possible for bilateral lesions. We investigated the possibility of restoring the human corneal surface with autologous corneal epithelial sheets generated by serial cultivation of limbal cells. METHODS: Cells were cultivated from a 1 mm2 biopsy sample taken from the limbus of the healthy eye of two patients with severe alkali burns, and thus complete loss of the corneal-limbal surface, of one eye. Normal corneal differentiation was tested with a specific biochemical marker. Autologous cultured corneal sheets were then grafted onto the damaged eyes of the two patients. The patients were followed up at more than 2 years after grafting. FINDINGS: We have shown that corneal progenitor cells are localised in the limbus, that cultured limbal cells generate cohesive sheets of authentic corneal epithelium, and that autologous cultured corneal epithelium restored the corneal surface of two patients with complete loss of the corneal-limbus epithelium. Long-term follow-up showed the stability of regenerated corneal epithelium and the striking improvement in patients' comfort and visual acuity. INTERPRETATION: The cultivation of corneal epithelium might offer an alternative to patients with unilateral lesions and a therapeutic chance to patients with severe bilateral corneal-limbal epithelial defects. Our findings give a new perspective on the treatment of ocular disorders characterised by stem-cell deficiency.

Burns, Chemical↗
PubMed1997

Clinical significance of Actinobacillus actinomycetemcomitans in young individuals during orthodontic treatment. A 3-year longitudinal study.

The aim of the present study was: (1) to assess longitudinally the occurrence of Actinobacillus actinomycetemcomitans (Aa) in young subjects wearing fixed orthodontic appliances compared to matched appliance-free controls; (2) to determine whether the presence of the micro-organism at baseline could influence the periodontal status assessed 3 years later. 70 subjects, 27 male and 43 female, aged between 12 and 20 years participated in the study: 35 subjects under orthodontic treatment with fixed appliances for at least 6 months, and 35 appliance-free individuals matched for age and gender. All subjects were free of clinically demonstrable loss of attachment. They all received oral hygiene instructions 2x during the 2 months preceding the first clinical and microbiological examination. No subgingival instrumentation was performed between baseline and the 3-year examination. Clinical parameters included gingival bleeding index (GBI), pocket probing depth (PPD) and measurements of attachment level (AL). Statistically significant differences were reported regarding frequency of detection of Aa between both groups at each examination. The %s of orthodontic subjects infected with Aa at the baseline and at the 3-year examination were 86% and 80%, respectively, while the corresponding figures for control subjects were 16.6% and 26.6%. The frequency distribution of %s of Aa in the total anaerobic subgingival flora among control subjects remained fairly stable, whereas the proportion of orthodontic subjects yielding Aa at a concentration > or = 1.0% dropped significantly from 32% at baseline to 19% at the 3-year visit. Calculations of the relative risk for increasing GBI and PPD in both groups when Aa was present at baseline, revealed that the orthodontic subjects positive for Aa had a negligible relative risk of experiencing worse periodontal conditions compared to orthodontic patients where Aa was not detected at baseline. In contrast, control subjects initially infected with Aa presented with a risk for increased GBI 6.6x higher than that for subjects without Aa. In conclusion, the present study confirmed previous cross-sectional findings reporting that young individual with an integer periodontium wearing fixed orthodontic appliances harbor Aa with a statistically significant greater frequency than appliance-free matched controls. However, although orthodontic patients exhibited more inflammation, their deteriorated clinical conditions could not be accounted for by the sole presence of Aa in their sulci. In contrast, appliance-free young subjects initially infected with Aa had a higher risk of experiencing more gingival inflammation than subjects without the bacterium during a 3-year observation period.

Actinobacillus Infections↗
PubMed1997

Laparoscopic adjustable silicone gastric banding (Lap-Band): how to avoid complications.

BACKGROUND: The laparoscopic application of LAP-BAND is gaining widespread acceptance as a gastric restrictive procedure. At the same time the reported morbidities (i.e., gastric perforation, stomach and/or band slippage) are cause for some concern. METHODS: From September 1993 until May 1997, 260 patients underwent LAP-BAND at the Department of Surgery at the University of Padova, Italy. RESULTS: The mortality rate was zero and the morbidity rate requiring reoperation was 3.4% (stomach slippage, gastric perforation, erosion). In order to avoid complications the key points of the technique are reviewed: (1) reference points for dissection (equator of the balloon, left crus); (2) retrogastric tunnel within the layers of the phrenogastric ligament; (3) embedment of the band; (4) proper outlet calibration; and (5) retention sutures. CONCLUSIONS: Attention to technical details is of paramount importance for a safe, standardized and effective operation.

Adolescent↗
PubMed1996

Clonal analysis of stably transduced human epidermal stem cells in culture.

We have transduced normal human keratinocytes with retroviral constructs expressing a bacterial beta-galactosidase (beta-gal) gene or a human interleukin-6 (hIL-6) cDNA under control of a long terminal repeat. Efficiency of gene transfer averaged approximately 50% and 95% of clonogenic keratinocytes for beta-gal and hIL-6, respectively. Both genes were stably integrated and expressed for more than 150 generations. Clonal analysis showed that both holoclones and their transient amplifying progeny expressed the transgene permanently. Southern blot analysis on isolated clones showed that many keratinocyte stem cells integrated multiple proviral copies in their genome and that the synthesis of the exogenous gene product in vitro was proportional to the number of proviral integrations. When cohesive epidermal sheets prepared from stem cells transduced with hIL-6 were grafted on athymic animals, the serum levels of hIL-6 were strictly proportional to the rate of secretion in vitro and therefore to the number of proviral integrations. The possibility of specifying the level of transgene expression and its permanence in a homogeneous clone of stem cell origin opens new perspectives in the long-term treatment of genetic disorders.

3T3 Cells↗
PubMed1996

The ocular albinism type 1 gene product is a membrane glycoprotein localized to melanosomes.

Ocular albinism type 1 (OA1) is an inherited disorder characterized by severe reduction of visual acuity, photophobia, and retinal hypopigmentation. Ultrastructural examination of skin melanocytes and of the retinal pigment epithelium reveals the presence of macromelanosomes, suggesting a defect in melanosome biogenesis. The gene responsible for OA1 is exclusively expressed in pigment cells and encodes a predicted protein of 404 aa displaying several putative transmembrane domains and sharing no similarities with previously identified molecules. Using polyclonal antibodies we have identified the endogenous OA1 protein in retinal pigment epithelial cells, in normal human melanocytes and in various melanoma cell lines. Two forms of the OA1 protein were identified by Western analysis, a 60-kDa glycoprotein and a doublet of 48 and 45 kDa probably corresponding to unglycosylated precursor polypeptides. Upon subcellular fractionation and phase separation with the nonionic detergent Triton X-114, the OA1 protein segregated into the melanosome-rich fraction and behaved as an authentic integral membrane protein. Immunofluorescence and immunogold analyses on normal human melanocytes confirmed the melanosomal membrane localization of the endogenous OA1 protein, consistent with its possible involvement in melanosome biogenesis. The identification of a novel melanosomal membrane protein involved in a human disease will provide insights into the mechanisms that control the cell-specific pathways of subcellular morphogenesis.

Albinism, Ocular↗
PubMed1996

Neglect for low luminance contrast stimuli but not for high colour contrast stimuli: a behavioural and electrophysiological case study.

We describe a patient with a right hemisphere lesion involving the frontal lobe, the post-central gyrus and the superior parietal lobule. Behavioural testing demonstrated severe left unilateral neglect to low luminance contrast stimuli, but not to high colour contrast stimuli. Evoked potentials to low contrast luminance gratings presented in the left hemifield were not reliable. However, equiluminant coloured gratings presented in the same hemifield evoked reliable electrophysiological responses, although longer in latency than those evoked in the right hemifield. These findings suggest that the patient has severe damage of the high contrast sensitivity magnocellular pathway in the right hemisphere, with minor involvement of the parvocellular pathway.

Brain Damage, Chronic↗
PubMed1996

VEP in neglect patients have longer latencies for luminance but not for chromatic patterns.

In patients with unilateral neglect, visual evoked potentials (VEP) to stimuli displayed in the left visual field are delayed compared with responses to right visual field stimuli. In the present study, 10 patients with right brain damage and neglect were tested with contrast-reversed sinusoidal gratings, modulated either in luminance or in chromaticity. For gratings of luminance contrast modulated over relatively high temporal frequencies (4-10.5 Hz), latencies of VEP were about 30 ms longer for stimuli presented to the contralesional (left) visual field than to the field ipsilateral to the lesion. For equiluminant stimuli modulated at relatively low temporal frequencies (1-4 Hz), however, latency was the same for both hemifields. As this condition activates predominately the parvocellular pathway the results are consistent with our previous suggestion that the delay observed with luminance stimuli in neglect patients results from selective disruption of the faster response of the magnocellular pathway.

Cognition Disorders↗
PubMed1996

Early visual processing in neglect patients: a study with steady-state VEPs.

Reliable steady-state visual evoked potentials (VEPs) were recorded in a group of 19 right brain-damaged patients with visuospatial hemineglect (Neglect), and two control groups: 15 left brain-damaged (LBD) patients and 12 right brain-damaged (RBD) patients without neglect. Moreover, VEPs were recorded in two rare cases of left brain damage and right visuospatial hemineglect. Stimuli were gratings phase-reversed at various temporal frequencies presented in the left and right visual field. In the Neglect group, VEPs to stimuli displayed in the left visual field (contralesional stimuli) had longer latencies. The delay was not present for the two control groups. As regards the VEP amplitudes, the Neglect group data showed a less distinctive pattern than in the case of latency. VEPs to stimuli contralateral to the lesion were smaller than those recorded for stimuli ipsilateral to the lesion in both Neglect and RBD groups. On the contrary, the VEP amplitudes for the two hemifields were comparable in the LBD group. In the case of left brain damage and neglect, VEPs to right visual field stimuli had longer latencies and lower amplitudes compared to the ipsilesional responses in both patients. Overall, the data support the view that, in most cases, early visual processing is not intact in the neglected hemifield.

Adult↗
PubMed1996

Eye movement patterns in reading as a function of visual field defects and contrast sensitivity loss.

Saccadic eye movements during reading were examined as a function of the side of visual field cut and the impairment of visual contrast sensitivity Five patients with various visual field defects were compared to five age-matched controls. Patients with right visual field defect showed an increase in the number of rightward saccades and a decrease in their amplitude, and patients with left visual field defects showed a pattern more similar to that of the control subjects. Two patients showed a selective deficit in the range of medium-high spatial frequency; they were the only patients to show a lengthening of mean fixation time during reading. These results indicate selective effects on reading depending on primary sensory defects. The clinical relevance of these findings is briefly discussed.

Adult↗