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Biomedical subjects

S M de Sousa

Publications and source records attributed to S M de Sousa.

7 recordsLinked to original sources
PubMed2001

Bilateral talon cusp: case report.

Talon cusp is an uncommon condition often present in the maxillary incisors and mandibular premolars. Morphologically, this anomaly has a well-delineated cusp that extends at least half the distance from the cementoenamel junction or cingulum area to the incisal edge. The alteration can cause clinical problems such as caries or occlusal interference. Management of the talon cusp varies according to the circumstances of the individual case and should be as conservative as possible. Presented is a case of bilateral bifid talon cusp in maxillary central incisors that was successfully managed with conservative therapy.

Acid Etching, Dental↗
PubMed1999

Unusual case of bilateral talon cusp associated with dens invaginatus.

CASE REPORT: This paper presents a rare case of bilateral talon cusp in permanent maxillary central incisors, one on the labial and another on the lingual surface of each tooth. The condition was associated with dens invaginatus in a maxillary permanent lateral incisor, but no developmental syndrome was identified. The left central incisor required no treatment because the aesthetic appearance was satisfactory and neither occlusal interferences nor caries were present. After careful investigation of the right lateral incisor, a sealant was applied. Root canal treatment was indicated for the right central incisor that had a wide open apex with thin, weak, divergent walls, and an apical radiolucency.

Adult↗
PubMed1998

Dens invaginatus: treatment choices.

Dens invaginatus is a well-known and well-established anomaly of development. Because it appears in various and complex forms, its diagnosis and treatment may be difficult. This paper presents different options based on anomaly variations, taking into consideration clinical and radiographic aspects as well as other criteria for treatment planning.

Apicoectomy↗
PubMed1994

Dens invaginatus in first mandibular premolar.

A case of dens invaginatus in a mandibular first premolar with periapical lesion is presented in which it was possible to perform non-surgical endodontic therapy. Dens invaginatus is a developmental malformation of teeth which results from abnormal morphodifferentiation. Due to their abnormal anatomical configuration, invaginated teeth present technical difficulties in their clinical management. The treatment modalities available to the clinician include: endodontic therapy, endodontic surgery, combined treatment, or extraction. In this case the treatment of choice, selected according to clinical and radiographic considerations, was endodontic therapy of the main root canal.

Adolescent↗
PubMed1993

Pertussis toxin expression in Drosophila alters the visual response and blocks eating behaviour.

Pertussis toxin inactivates certain G-proteins by introducing an ADP-ribose group near the carboxyl-terminus of the alpha-subunit. The major pertussis toxin substrate in Drosophila tissues is Go alpha. We introduced a pertussis toxin gene under control of the hsp70 heat-shock promoter into the Drosophila genome. When heat-shocked, transformed flies produce active pertussis toxin which ADP-ribosylates endogenous Go alpha. Pertussis toxin is expressed in photoreceptors, in the lamina of the eye and in epithelial cells lining the gut. As expected from the absence of Go alpha in photoreceptors, pertussis toxin does not affect the photoreceptor component of the Drosophila visual response. However, it abolishes light on- and off-transients in the electroretinogram. These transients normally arise from the lamina, a tissue where Go alpha transcripts have been detected. Pertussis toxin expression also blocks embryonic development and shortens the lifetime of adult Drosophila. Following heat-shock, transformed adults are active, but they fail to take up nutrients because they stop eating. High energy metabolites are significantly depleted shortly after pertussis toxin expression is induced and the flies die within 48 h.

Adenosine Diphosphate Ribose↗
PubMed1989

The Drosophila Go alpha-like G protein gene produces multiple transcripts and is expressed in the nervous system and in ovaries.

Drosophila melanogaster cDNA clones coding for the alpha subunit of a Go-like G protein have been isolated. The sequence of two cDNA clones shows there is alternative splicing in the 5'-coding region which, on conceptual translation, would give rise to two proteins with slightly different amino termini. A partial genomic clone indicates there are four introns in the carboxyl-terminal half of the clone. Two transcripts, 3.8 and 5.3 kilobases long, are expressed at a high level in the heads of adult flies and also in larvae, pupae, and embryos. Hybridization of the cDNA probes to sections of adult flies indicates the RNA is present predominantly in nervous tissue (in the cortex of the brain and the thoracic ganglion); it is also expressed in the ovaries. Transcripts corresponding to both cDNAs are present in the central nervous system, but only one of them is found in detectable levels in the ovaries. The gene maps to 47A on the Drosophila second chromosome.

Amino Acid Sequence↗