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Biomedical subjects

A Carrassi

Publications and source records attributed to A Carrassi.

At least 19 recordsLinked to original sources
PubMed1992

Prevention of local relapses and new localisations of oral leukoplakias with the synthetic retinoid fenretinide (4-HPR). Preliminary results.

This paper analyses preliminary results of a randomised chemoprevention trial in patients surgically treated for oral leukoplakia started in 1988 at the Istituto Nazionale Tumori of Milan with the synthetic retinoid N-(4-hydroxyphenyl)-retinamide (4-HPR). To date 115 patients have been randomised, after surgical excision of oral leukoplakia, to receive 200 mg 4-HPR daily for 52 weeks versus no intervention. 80 patients completed the 1-year intervention, 41 in the control group and 39 in the 4-HPR group. During this period 12 local relapses or new lesions occurred in the control group and three in the 4-HPR group. Only 5 patients interrupted the intervention because of toxicity. No impaired dark adaptation was observed. It is concluded that 4-HPR is well tolerated and seems efficacious in preventing relapses and new localisations during the treatment period. This promising trend needs further confirmation.

Adult↗
PubMed1991

[An assessment of the proliferative activity in oral lichen planus].

The author's aim was to evaluate the cell proliferation of oral lichen planus, by an in vitro labelling technique using tritiated thymidine (TLI). For this purpose six patients with oral lichen planus and six control volunteers with oral mucosa clinically sound were studied. The cell kinetic parameter was investigated by counting cells from autoradiographs on histological sections of the biopsies. Significant differences were found between the basal TLI of the two group (p = 0.002) but no between the epithelial TLI (Wilcoxon test).

Biopsy↗
PubMed1990

[Study of cellular kinetics in oral leukoplakia].

The Authors aim was to study the Labeling Indices (LI) of 12 subjects with oral leukoplakia, using an in vitro labeling technique with tritiated thymidine (Silvestrini-Kit, Ribbon spa, Milan). Twelve volunteers of our Dental Clinic were enrolled in this study as a control group. The kinetic parameter was investigated by counting cells from autoradiographs on histological selections of the biopsies. By a Wilcoxon test, significant differences were found between the LI of the two groups: p = 0.00003. Finally, a comparison has also been made between LI of these lesions and the LI of oral squamous cell carcinomas.

Adult↗
PubMed1990

A new method of bacterial identification using gold immunolabelling and scanning electron microscopy.

This study sought to develop an immunolabelling technique to identify specific bacteria by scanning electron microscopy. Bacterial suspensions were prepared of Actinobacillus actinomycetemcomitans, Porphyromonas (Bacteroides) gingivalis and mixtures of these species with other genera of common oral microorganisms. This method was also used to examine subgingival plaques from 6 subjects with chronic adult periodontitis. Sample preparation consisted of prefixation of the bacterial suspensions with 0.2% glutaraldehyde, incubation with species-specific rabbit antisera and goat anti-rabbit IgG conjugated with colloidal gold particles, postfixation in 2% glutaraldehyde and dehydration in ethanol. Finally, the samples were dried, coated with evaporated carbon and examined by scanning electron microscopy. Pure cultures and artificial mixtures of A. actinomycetemcomitans and Bact. gingivalis were specifically labelled by gold probes as demonstrated by both secondary and back-scattered imaging. These species were also evident in samples of subgingival plaque. The findings indicate that this new technique can be used to identify specific microorganisms both in plaque samples and on the root surface of extracted teeth.

Actinobacillus↗
PubMed1990

Identification of Actinobacillus actinomycetemcomitans by gold immunolabeling and scanning electron microscopy.

Recent evidence suggests that dental plaque is not a homogeneous bacterial mass but, on the contrary, specific bacterial morphotypes and species may be preferentially located within certain microenvironments. The aim of the present study was to develop combined gold immunolabeling and scanning electron microscopic (SEM) techniques for the identification of periodontal pathogens in subgingival dental plaque and on the root surfaces of extracted teeth. Suspensions of pure A. actinomycetemcomitans cultures or suspensions of A. actinomycetemcomitans mixed together with other oral bacteria were prepared, labeled with goat anti-rabbit IgG conjugated with 5 nm or 40 nm colloidal gold particles, and observed by SEM using both secondary and back-scattered imaging. Scanning electron microscopy demonstrated that the A. actinomycetemcomitans bacterial cell surface was specifically labelled. There was no cross-reaction with any of the other bacterial morphotypes. Only the labeled A. actinomycetemcomitans were visible in mixtures examined by back-scattered imaging scanning electron microscopy. The combined techniques of gold immunolabeling and SEM may, therefore, be useful in identifying A. actinomycetemcomitans in subgingival plaque samples and on the root surfaces of extracted teeth as well as in studies of bacterial ecology in dental plaque, in general.

Actinobacillus↗
PubMed1989

Impacted molars.

Explore the source record for details and available documents.

Humans↗
PubMed1989

Early plaque colonization on human cementum.

We have described the morphology of developing plaque on cementum in an in vivo human model. Slabs of cementum obtained from sound teeth, rendered anorganic with 5% sodium hypochlorite, were glued to orthodontic brackets and positioned on the upper canines, premolars and molars in 8 volunteers. The brackets were removed after 2, 4, 8, 24 h and processed for scanning electron microscopy (SEM). Within 2 h, a thin pellicle covered the cementum surface, with few micro-organisms detectable. At 4 and 8 h, coccoid plaques were present. Filaments inserted perpendicularly to the plaque surface were seen at 24 h. The results indicate that early bacterial colonization of human cementum is a selective process, mediated by an organic pellicle and mainly involves cocci.

Bacteria↗
PubMed1989

Periodontitis in a patient with chronic neutropenia.

The aim of this investigation was to obtain information about the composition and the morphology of the microorganisms that inhabit the root surface of a patient with chronic neutropenia and severe and progressive periodontitis. In addition, gingival biopsies were studied by both scanning and transmission electron microscopy (SEM and TEM) to look for bacteria within the gingiva. Dark field microscopy (DFM) revealed 50% spirochetes, 30% motile rods, and 20% coccoid forms. Fourteen extracted teeth studied by SEM showed that the distribution of different bacterial morphotypes varies along the root surface and spirochetes are the prevailing bacteria on the most apically located plaque. TEM analyses of gingival tissue revealed no bacterial invasion within the gingiva. This study suggests that spirochetes may play an important role in the etiology of periodontitis associated with chronic neutropenia. In spite of neutropenic status, there was no bacterial invasion into the gingiva, suggesting that host reaction to dental plaque has not been abolished in this condition.

Adult↗
PubMed1989

[Amount of mineralized tissue removed by root planing].

The Author's aim was to determine the amount of mineralized tissues removed during root planing conducted by means of a curette, using a profilometer. Records were kept at time 0 and after 4 cycles of 5 strokes each. Mean values of final records show that the average of tissue removal, expressed in microns, was greater than the mean thickness of cementum in the instrumented areas.

Dental Cementum↗
PubMed1989

[Precancerous oral lesions. Diagnostic and therapeutic protocol].

The NRC (National Research Council) task force on head and neck cancer issued this document to help clinicians involved in diagnosing and treating precancerous oral diseases. Chapter 1 includes definition, epidemiology, risk factors (alcohol, smoking, poor oral hygiene), WHO classification, clinical picture of leukoplakias, erythroplasia, lichen planus, as well as their natural history. Chapter 2 points out the clinical signs to be looked for in order to make a proper diagnosis and discusses biopsy techniques. Chapter 3 deals with therapeutic procedures (surgical technique and medical treatment), while Chapter 4 concerns follow-up according to the clinical and histological diagnosis. Finally, some statistical forms are enclosed: Form 1 consists of information regarding educational qualifications, occupation, alcohol consumption, smoking and dietary habits; Form 2 consists of information about previous diseases and the history of the present disease; Form 3 records the signs and symptoms observed for the precancerous lesion; Form 4 records treatment modalities; Form 5 records patient follow-up.

Humans↗
PubMed1988

The role of scanning electron microscopy in periodontal research.

During recent years a great amount of research has led to a better understanding of the etiology, pathogenesis and pattern of progression of periodontal diseases. Scanning electron microscopy (SEM) has contributed to this improvement, mainly with respect to histology of periodontal tissues, the description of the morphology and distribution of bacteria on the exposed root surface, analysis of the host-parasite interactions on the gingival pocket wall, and morphological evaluation of root treatment. This review deals with all these topics. Unusual types of SEM research are also described and discussed. Uncommon sample preparation techniques for SEM in periodontal research are described. SEM in periodontal research should be of great application in the near future. Cathodoluminescence, back-scattered emission and immunolabelling techniques will be formidable tools in this field of dentistry.

Gingiva↗
PubMed1988

Dermochondrocorneal dystrophy (François' syndrome). Report of a case.

Dermochondrocorneal dystrophy (François' syndrome) is an extremely rare disorder characterized by firm, nodular lesions involving the hands and the face; osteochondrodystrophy of the peripheral extremital bones, resulting in limitation of movement; and corneal dystrophy marked by white or brownish opacities. A nonfamilial case of dermochondrocorneal dystrophy was studied in a 45-year-old woman who had severe involvement of the gingival and palatal mucous membranes.

Bone Diseases↗