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Biomedical subjects

R Scotti

Publications and source records attributed to R Scotti.

At least 19 recordsLinked to original sources
PubMed1992

Synthesis and antibacterial activity of a series of basic amides of teicoplanin and deglucoteicoplanin with polyamines.

Basic carboxamides of teicoplanin A2 (CTA) and its aglycon (TD) are prepared by condensation of the 63-carboxyl function of these antibiotics with linear or branched polyamines. The antimicrobial activities of some of the resulting compounds were better than those of the unmodified antibiotics. The presence of more than one basic group in the amidic chain enhanced the in vitro activity of some TD-amides against Gram-negative bacteria; two of these derivatives were also effective in vivo against Escherichia coli septicemia in the mouse. Among the CTA derivatives, the amide with spermine showed some unexpected in vitro activity against Gram-negatives. Both CTA- and TD-amides with polyamines are very soluble in water over a wide range of pH and are very hydrophilic.

Amides↗
PubMed1992

Antimicrobial activity of MDL 62,873, a semisynthetic derivative of teicoplanin, in vitro and in experimental infections.

MDL 62,873 is an amide derivative of teicoplanin A2-2. Like those of natural glycopeptides, its antibacterial activity is mediated by inhibition of cell wall peptidoglycan synthesis. Against streptococci and enterococci, the in vitro activity of MDL 62,873 was similar to that of teicoplanin and greater than that of vancomycin. Against staphylococci, it has activity similar to that of vancomycin, and it was significantly more active than teicoplanin against coagulase-negative isolates. Like teicoplanin and vancomycin, MDL 62,873 had slow but significant bactericidal activity (99 to 99.9% killing in 24 h) against staphylococci at concentrations near the MIC. In murine septicemia studies with Staphylococcus aureus, Streptococcus pyogenes, and Streptococcus pneumoniae, the 50% effective doses were lower than those of vancomycin. In staphylococcal endocarditis in rats, MDL 62,873 at 20 mg/kg of body weight and vancomycin at 40 mg/kg, both doses given intravenously twice daily, had similar efficacies in reducing the heart bacterial load. These results probably reflect the longer half-life of MDL 62,873, which has a pharmacokinetic profile in rats similar to that of teicoplanin.

Animals↗
PubMed1992

Synthesis and biological activity of O56-substituted carboxyesters and carboxamides of teicoplanin aglycone.

A series of O56-substituted carboxyester or carboxyamide derivatives of deglucoteicoplanin (TD) was prepared by condensation of the 56-hydroxyl function with various alkylating agents of general formula RBr, where R represents functional groups with different physico-chemical properties. The modifications at position 56 influenced the antimicrobial activity of the new derivatives; activity depended on the structure of various R groups, their ionic properties, and their steric hindrance. The activity of the new compounds did not show any significant improvement when compared with TD. The physico-chemical and antibacterial properties of the synthesized compounds are reported.

Anti-Bacterial Agents↗
PubMed1991

Clinical applicability of the radiographic method for determining the thickness of calcified crown tissues.

A previously developed radiologic method for determining the thickness of the mineralized crown tissues was applied clinically to 10 teeth diagnosed for extraction. The thickness of the mineralized crown tissues as measured radiographically was compared with that measured directly on the extracted tooth. A statistical analysis indicated accuracy of 4.46%, equivalent to an error of 0.12 mm.

Dental Cementum↗
PubMed1991

Ciprofloxacin monotherapy for acute pelvic infections: a comparison with clindamycin plus gentamicin.

This prospective, randomized controlled study compared the efficacy and safety of ciprofloxacin alone versus a conventional two-drug regimen, clindamycin with gentamicin. The study group included 71 patients hospitalized for pelvic infections such as acute (N = 33) and chronic (N = 8) salpingitis, tubo-ovarian abscesses (N = 11), endometritis (N = 9), septic abortion (N = 3), and other categories (N = 7). Twenty-two of 35 patients on ciprofloxacin and 20 of 36 on clindamycin plus gentamicin had culturable pathogens: gonococci in 28, anaerobes in six, chlamydia in four, and associated pathogens in 19. Complete clinical and bacteriologic cure was achieved in 21 of 22 (95%) in the ciprofloxacin group and 19 of 20 (95%) in the clindamycin plus gentamicin group. The mean duration of intravenous/oral ciprofloxacin therapy was 3.7/7.2 days, and it was 3/6.6 days for clindamycin plus gentamicin. Ciprofloxacin, a new quinolone, appears to be safe as a single-drug therapy and was as effective as the combination of clindamycin plus gentamicin for the treatment of severe pelvic infections requiring hospitalization.

Acute Disease↗
PubMed1990

Generation of chromosome size polymorphism during in vivo mitotic multiplication of Plasmodium berghei involves both loss and addition of subtelomeric repeat sequences.

Extensive chromosome size polymorphism arises in Plasmodium berghei during in vivo mitotic multiplication. Size differences between homologous chromosomes involve rearrangements occurring in the subtelomeric portions while internal chromosomal regions do not contribute significantly to chromosome size polymorphism. Differences in the copy number of a 2.3-kb subtelomeric repeated unit are shown to correlate with size variations, and in at least one case to account completely for the size difference between two variants of the same chromosome.

Animals↗
PubMed1990

Synthesis and biological activity of some derivatives of rifamycin P.

A series of derivatives of rifamycin P, an antibiotic produced by fermentation of a mutant strain of Nocardia mediterranea or by chemical modification of rifamycin S, have been prepared. The structures of these compounds were determined by 1H NMR, IR, UV, and LC/MS. Their in vitro and in vivo antibacterial activities in comparison with rifampicin and two other rifamycins under investigation were evaluated. The derivatives were more active than rifamycin P against Mycobacterium avium complex and other slowly and rapidly growing nontuberculous mycobacteria which frequently cause systemic infection in patients with AIDS. 2'-(Diethylamino)rifamycin P (P/DEA) appears suitable for further investigation.

Animals↗
PubMed1990

The unreliability of facial measurements in the determination of the vertical dimension of occlusion in edentulous patients.

The aim of this research was to test the reliability of skin markers in the determination of the V.D.O. in edentulous patients during prosthetic rehabilitation. Two resin baseplates were constructed: on the upper one a modified pin of the Central Bearing Point registration device was fixed with impression compound. The height of the pin could be altered by rotating the pin directly in the patient's mouth with a probe. Two lead spheres were inserted on the resin base-plate as bone markers, and two others were fixed to the skin as markers, one above (end of nose) and one below (point of chin) the oral commissure. Five lateral cephalometric radiographs were exposed for each patient, raising the V.D.O. by 1.2 mm on each occasion. Statistical analysis of measurements made on the resulting radiographs showed a very strong correlation between bone markers and pin position, whereas great variation and considerable differences were found between skin markers and bone as well as measurements.

Adult↗
PubMed1990

[Direct rebasing of temporary crowns in the fixed denture. An experimental assessment of the increase in heat at the pulp cavity level].

Self-curing resins are generally used to directly temporary prostheses on the crown abutments. This technique enables the operator to obtain a better marginal adaptation of the temporary prosthesis. The risk of such a procedure is the inflammation of the pulp due to the exothermic polymerization reaction of self-curing resins. The authors suggest experimentally evaluating the rate of thermic increase within the pulp cavity of an extracted tooth while directly relining a temporary crown.

Composite Resins↗
PubMed1990

[A comparative evaluation of the increase in heat during the polymerization reaction of resins for temporary fixed dentures].

Self-curing resins enable the operator to prepare directly temporary prosthesis on single crown abutments. However such a technique may involve the danger of an inflammation of the pulp, due to the exothermic polymerization reaction of self-curing resins. The Authors suggest experimentally assessing the thermic increase during the polymerization reaction of seven different resins. Moreover they want to estimate the influence of the ratio monomer-polymer on the thermic curve of such reactions.

Composite Resins↗
PubMed1989

A radiologic method for determining the thickness of the hard crown tissues.

This study describes a radiologic method that provides a reliable evaluation of the thickness of the hard crown tissues of the tooth scheduled for prosthetic and conservative preparation. The first stage consisted of calculating the discrepancy between the actual dimensions of the specimen under examination and the dimensions of the same specimen as measured and radiographed. Some coefficients of distortion were calculated for the distance(s) more usually involved clinically. Radiographs were made by using the "paralleling" technique. In the second stage, radiographs were made of 83 extracted teeth (22 incisors, 12 canines, and 51 premolars). On the resulting radiographs some prefixed distances were measured. Finally, to gain an anatomic comparison of the values obtained radiologically, 24 of the previously radiographed teeth were sectioned along the sagittal plane at the diameter, and measurements were made and compared with the radiologic data to which the correction coefficients had been applied.

Data Interpretation, Statistical↗
PubMed1989

Presence of contaminating mitochondrial DNA from host reticulocytes in experimental infections of Plasmodium berghei.

Superposition of two unrelated processes, namely terminal reticulocyte differentiation and synchronous plasmodial development, takes place in experimental infections of Plasmodium berghei. The first process is shown to be responsible for the appearance of some discrete restriction bands of host origin when DNA is extracted from leucocyte-free blood containing synchronous parasites at early stages of infection. These discrete DNA fragments cross-hybridize with host cell mitochondrial DNA. Purification steps are suggested to reduce this effect, which might be relevant also in the case of other plasmodial species exhibiting preference for reticulocytes as host cell.

Animals↗
PubMed1989

[Mounting posterior teeth in complete dentures].

The more common techniques for analysing the alveolar ridge in full dentures were examined. Both the linear analysis and the two-dimensional one, proposed by Pound, were described. The ridge-transfer method was found to be three-dimensional, thus allowing the construction of full dentures which are more stable during each phase of mastication.

Alveolar Process↗
PubMed1989

[Evaluation of the clinical effectiveness of biofeedback EMG on muscular relaxation and painful symptomatology].

The therapeutic effectiveness of EMG biofeedback on muscular relaxation and pain symptomatology has been analysed in a group of 24 dysfunctional patients presenting consecutively at the Prosthesis Department of the Odontostomatological Clinic. A good level of muscular relaxation was achieved in 22 cases; pain symptomatology disappeared totally in 19 and reduced considerably in 3 of 24 patients examined. Therapy failed in 2 cases. The method thus presents unquestionable therapeutic value in dysfunctional patients, particularly in cases with symptomatology that is mainly due to muscular hyperactivity.

Adult↗
PubMed1989

[Electromyographic evaluation of muscular tension in dysfunctional subjects in relation to normal subjects].

Electromyography has been used to analyse the myoelectric activity of the masticatory muscles in 130 dysfunctional patients in comparison with normal subjects. Of the muscles examined, those presenting greater basal tension were also identified. Myoelectric activity proved greater, at postural values, in dysfunctional patients; by contrast, subjects without craniomandibular symptomatology presented normally low initial values. As for the analysis of the muscular group presenting greater tension, analysis of the results did not produce statistically significant percentages pointing to the prevalence of one muscular group over another.

Adolescent↗