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Biomedical subjects

S Calderon

Publications and source records attributed to S Calderon.

At least 19 recordsLinked to original sources
PubMed2004

Ectomesenchymal chondromyxoid tumour of the anterior tongue.

Ectomesenchymal chondromyxoid tumour (ECT) of the anterior tongue was first described in 1995. To date, only 23 cases have been reported in the literature. Two new cases of ECT have been described, with immunohistochemical analysis including cytokeratin (CK) profile, GFAP, S-100 protein, SMA, CD-57, EMA, desmin and Ki67. Tumour cells showed intense and diffuse staining for GFAP and diffuse staining for S-100 protein. Pan-keratin, high- and low-molecular-weight CK, CK 7, 8, 18, 19 and 20 were negative. Tumour cells were also negative for desmin, SMA, CD-57 and EMA. Ki67 was positive in only scattered cells. The findings of the present study support the suggested ectomesenchymal origin for ECT, rather than myoepithelial salivary gland origin. The low Ki67 expression is in agreement with the low growth rate, small size and lack of mitotic activity in the present cases, as well as in those previously described.

Adult↗
PubMed2003

Radiological features of glandular odontogenic cyst.

OBJECTIVES: To present five new cases of glandular odontogenic cyst (GOC) and to review the radiological features at presentation as reported in the English literature. METHODS: From 1993 to 2002, five patients in our department were diagnosed with GOC based on histopathological findings and supported by radiography and CT. The radiographic features of the new GOC cases were analysed in addition to 51 literature cases. RESULTS: There were 31 male and 25 female patients, aged 14-90 years (mean 50 years). The mandible was involved in 80% and the maxilla in 20%; most of the lesions were located in the anterior jaw. Radiographically, 52% of the lesions were unilocular and 48% were multilocular; 94.5% showed well defined borders, which were sclerotic in 7.7% and scalloped in 13%. Information on cortical plate integrity was available in only 24 cases: 50% showed perforation, 8.3% erosion of the cortical plates and 8.3% thinning of the cortical plates. Root resorption was reported in 22% of patients and tooth displacement in 24.4%. CONCLUSIONS: Data collected indicate that GOC has potentially aggressive behaviour, with expansion and perforation in a significant number of cases. We recommend the use of multiple plane radiographs, with CT reserved for large lesions, especially those that are multilocular or involve extragnathic structures.

Adolescent↗
PubMed2002

[Update review on prevention and early diagnosis in oral cancer].

Oral cancer is a major health problem in some parts of the world, especially in developing countries. Worldwide, the annual incidence exceeds 3,000,000 new cases. The main risk factors are tobacco and alcohol. However, dietary factors, viruses and possibly genetic predisposition have also been associated with oral cancer. Several oral lesions such as leukoplakia, erythroplakia and lichen planus carry an increased risk for malignant transformation in the oral cavity. Prognosis of oral cancer differs significantly between specific oral locations, with cancer of the lip for example having a much better prognosis than at the base of tongue or on the gingiva. Prognosis of intra-oral cancer is generally poor, with a five-year survival less than 50 percent. Local recurrences as well as lymph node metastases occur in a significant percentage of patients, while distant metastases are less frequent. Prognosis correlates mainly with the size of the lesion and the nodal status at the time of diagnosis, therefore early detection of small, stage-1 oral cancer can reduce mortality and morbidity. Oral lesions can be easily observed by direct visualization, however, knowledge of the differential diagnosis of oral lesions is mandatory for early diagnosis of malignant and pre-malignant lesions in the oral cavity. Use of screening and detection aids such as vital stains and Oral CDX can increase the number of cases diagnosed at an early stage, or even in the pre-malignant stage. Development of molecular markers can improve the early diagnosis and can help in predicting treatment response. New treatment modalities including tumor specific antibodies and gene therapy are emerging, giving more hope for patients with oral cancer. There is an important role for the dentist in both early diagnosis of pre-malignant and malignant lesions, and in prevention by educating the patients of the risks associated with tobacco, alcohol and dietary factors.

Alcohol Drinking↗
PubMed2001

Effect of facial pressure garments for burn injury in adult patients after orthodontic treatment.

Pressure garments are commonly used to prevent and control hypertrophic scar tissue. Complications are unusual, though in children with facial burns, pressure garments may lead to skeletal and dental deformities. Studies in adolescents and adults are sparse. We describe a 24-year-old woman who sustained facial burns. Prior to injury, the patient had undergone premolar extraction in preparation for orthodontic treatment. Her post-burn care consisted of application of a Jobst pressure garment. After 2 months treatment, severe deformation of the dental-alveolar structure was observed. This reports suggests that adults after dental extraction are at a high risk of dental-alveolar deformities from pressure garments and might benefit from the use of occlusal wafers.

Adult↗
PubMed2001

Radiological and clinical features of calcifying epithelial odontogenic tumour.

OBJECTIVES: To analyse systematically the radiographic features of the calcifying epithelial odontogenic tumour (CEOT). METHOD: Clinical and radiological features of 67 cases of CEOT (four new and 63 from the literature) were analysed. RESULTS: There were 27 (41%) males and 39 (59%) females with a male-to-female ratio of 1 : 1.5. Age ranged from 13 - 77 years (mean 43.5 years), with a peak in the fourth and fifth decades. The mandible was involved in 74% of the cases and 69% of all lesions were in the posterior area. The mixed radiolucent-radiopaque pattern was the most frequent (65%), with 32% radiolucent and 3% radiopaque. Coronal clustering of the radiopaque material was found in 12% and in one case, a 'driven snow' pattern of the radiopaque material was clearly recognizable. Lesions were unilocular in 58%, multilocular in 27% and not loculated in 15%. The unilocular type was more frequent in the maxilla than in the mandible. Borders were well defined and corticated in 20%, defined but not corticated in 59% and diffuse in 21%. Sixty per cent were associated with impacted teeth. Lesions larger than 3 cm tended to be more frequent in the mandible, mixed radiolucent-radiopaque and to have a higher proportion of diffuse borders than the smaller lesions. CONCLUSION: Radiographic features which have been considered characteristic of CEOT, coronal clustering and 'driven snow' patterns, are seen in only a small percentage of cases.

Adult↗
PubMed2000

Maxillomandibular brown tumor--a rare complication of chronic renal failure.

We report a 17-year-old hemodialysis patient with a rapidly growing maxillary mass diagnosed as a brown tumor. Although successful control of the parathyroid hormone (PTH) levels was achieved by treatment with vitamin D pulse therapy, the lesion progressed, invaded the maxillary sinus, and caused severe eating and speech disabilities. No recurrence was observed following surgical excision. The differential diagnosis and considerations regarding the causes of the disease in a child, therapy options, and review of the literature are presented.

Adolescent↗
PubMed2000

Effect of luteinising-hormone in vivo on ovarian cell subpopulations of newly-hatched chicks.

1. We analysed the number and size of different ovarian cell subpopulations of newly-hatched chicks by ovarian cell suspension count and morphometric/stereological methods as well as delta5-3beta-hydroxysteroid dehydrogenase (delta5-3beta HSD) activity in these cells treated in vivo with LH during embryonic development. 2. Fertile White Leghorn eggs received 1 microg LH applied to the chorioallantoic membrane on days 13, 15, and 17 of incubation. All animals were killed within 24 h after hatching, the left ovary was dissected and processed. 3. The results indicate that the number of germ, pregranulosa, interstitial and undifferentiated cells was not affected by LH treatment. However, we observed an increase in the size of individual interstitial cells of the ovarian medulla. In these cells, delta5-3beta HSD activity was increased in response to LH. 4. These findings suggest that LH does not exert a proliferative effect on the cells of the prefollicular ovary of the chick and that interstitial cells can be target cells for LH, increasing their steroidogenic activity due to LH treatment.

3-Hydroxysteroid Dehydrogenases↗
PubMed1999

Radiological and clinical features of aneurysmal bone cyst of the jaws.

PURPOSE: To evaluate the clinical and radiological features of aneurysmal bone cyst (ABC) of the jaws. MATERIALS AND METHODS: A total of 64 cases (60 from the English-language literature and four new cases) were studied and critically evaluated with emphasis on the radiological features. RESULTS: Age at time of initial diagnosis ranged from 4-78 years, with a mean age of 21.5 years and median age of 17 years. There were no differences in gender distribution. The ratio between the mandible and maxilla was 2.4:1. Ninety-two per cent of the lesions were located in the posterior region of the jaws. Lesions were radiolucent in 87% of cases, radiopaque in 2% and mixed in 11%. Fifty-three per cent were multilocular, 43% unilocular and 3% not loculated. The border of the lesions was defined but not corticated in 39%, well defined in 33% and diffuse in 28%. CONCLUSIONS: ABC has a variable radiological appearance and should be considered in the differential diagnosis of any unilocular or multilocular radiolucent lesion of the jaws as well as any mixed radiolucent-radiopaque lesion.

Adolescent↗
PubMed1999

Abuse liability assessment of neuroprotectants.

There has been considerable interest in the potential of N-methyl-D-aspartate (NMDA) receptor antagonists in the treatment of a diverse group of neurological disorders including cerebral ischemia and neurodegeneration. The amino acids L-glutamate and L-aspartate have been shown to possibly mediate excitatory synaptic transmission in the central nervous system (CNS) via selective excitatory amino acid receptors. Competitive and noncompetitive antagonists acting at the NMDA receptors have been shown to possess relevant activity. However, NMDA antagonists can produce a variety of adverse neurobehavioral effects in both animals and humans. These adverse events are particularly pronounced with NMDA antagonists (phencyclidine (PCP), ketamine, and MK-801) that have dissociative anesthetic properties and block NMDA receptor-mediated responses by binding to the cation channel of the NMDA receptor complex. When a new pharmaceutical product demonstrates structural similarity and/or a similar pharmacological profile with a known drug of abuse, the characterization of its abuse potential is needed by the FDA for scientific review. The abuse liability assessment is based upon an evaluation of data on the chemistry, pharmacology (preclinical and clinical), pharmacokinetics, and pharmacodynamic profiles of the drug, and the adverse events/effects reported in clinical trials. The evaluation of the drug's abuse potential is determined relative to pharmacologically similar drugs. This includes determination of the drug's receptor binding efficacy, preclinical pharmacology, reinforcing efficacy, discriminative stimulus effects, dependence-producing potential, pharmacokinetics, and assessment of the clinical efficacy-safety database relative to abuse and clinical abuse liability studies. It has been well established that high-affinity noncompetitive NMDA antagonists have reinforcing efficacy and can serve as discriminative stimuli in operant procedures. In a variety of species in drug discrimination studies, each antagonist is capable of generalizing to the others, and it is believed that these effects may be mediated through the NMDA blockade. The generalization of each substance for another suggests production of common subjective effects in humans.

Animals↗
PubMed1997

The coronoid process as a cause of mandibular hypomobility--case reports.

In an attempt to draw the clinician's attention to the coronoid process site while evaluating the aetiology of the restriction of mandibular opening, four cases are illustrated. These cases represent a diversity of causes hampering the free rotational movement of the coronoid process in space during jaw function. Case 1 is an example of unilateral hyperplastic coronoid process and osteochondroma; case 2 shows unusually shaped short and divergent coronoid processes combined with a bucally displaced maxillary third molar on one side; cases 3 and 4 represent an anatomical variation of an extremely narrow vestibular space due to the close proximity of the medial aspect of the coronoid process to the distal molar. It is suggested that each clinical examination include the width of the buccal vestibular space while performing mandibular movements.

Adult↗
PubMed1996

Human delta opioid receptor: functional studies on stably transfected Chinese hamster ovary cells after acute and chronic treatment with the selective nonpeptidic agonist SNC-80.

The SNC-80 series of nonpeptidic agonists for the delta-opioid receptor are being developed as potential analgesic drugs. It is important to understand their acute and chronic effects at human delta-opioid receptors. Thus, we measured the ability of SNC-80 and [D-Pen2,4'-Cl-Phe4,D-Pen5]enkephalin to inhibit forskolin-stimulated adenylyl cyclase activity in recombinant Chinese hamster ovary cells stably expressing the cloned human delta-opioid receptor. The calculated EC50 values for [D-Pen2,4'-Cl-Phe4,D-Pen5]enkephalin and SNC-80 were 0.6 +/- 0.1 nM and 6.3 +/- 0.1 nM, respectively. Pretreatment of these cells with SNC-80 (100 nM) for 24 hr produced 1) a time-dependent reduction of delta receptor density, as measured by radioligand binding studies with [3H]naltrindole; 2) a shift in the EC50 value of SNC-80 from 7.7 +/- 4.2 nM to 44.1 +/- 12 nM, as measured by the cyclic AMP assay; 3) a reduction in the maximum inhibition of adenylyl cyclase activity from 86% to 48%; 4) a marked increase in the forskolin stimulation of basal cyclic AMP accumulation by nearly 100% (from 442 pmol/mg of protein to 824 pmol/mg of protein); and 5) a 5-fold increase in forskolin-stimulated cyclic AMP accumulation after addition of naltrindole. These studies showed that SNC-80 produced desensitization and down-regulation of human delta-opioid receptors in recombinant Chinese hamster ovary cells after chronic treatment and that this effect was associated with an increase in adenylyl cyclase activity.

Animals↗
PubMed1995

Disturbed lower denture stability due to lipoma in the floor of the mouth.

An unusual case of lipoma arising in the floor of the mouth of a 70-year-old man is presented. The unusual appearance suggests that the tumour be included as a rare possibility in the differential diagnosis of swellings in the floor of the mouth that can also adversely affect lower denture stability.

Aged↗