Uterine contractility as a cause of amniotic band syndrome.

OBJECTIVE: The objective of this study was to determine whether puncturing the uterine wall and the amnion causes uterine contractions that result in fetal abnormalities. MATERIALS AND METHODS: An experimental study was performed using four groups of three female rabbits. Group A received a puncture of the amniotic membranes of one of the uteri on day 15 of gestation followed by group B on day 16, group C on day 17, and group D on day 18. The duration and force of contractions and fetal abnormalities were determined. RESULTS: There were immediate contractions after the puncture, which lasted 20 to 132 seconds with forces that ranged from 309 to 4,411 mg. All of the experimental fetuses exhibited anomalies of the head and extremities, exencephaly, cleft palates, and an absence of eye-lids. CONCLUSION: Injury to the uterine wall and the aniion can immediately cause uterine contractions, which are associated with different types of fetal abnormalities.

Immunoexpression of matrix metalloproteinases and their inhibitors in different areas of oral squamous cell carcinoma.

BACKGROUND: Several studies have shown the participation of MMPs in oral squamous cell carcinoma, the most frequent malignant neoplasm of the oral cavity. The expression of some MMPs correlates with a more aggressive biological behaviour. The objective of this study was to determine which MMPs and TIMPs were expressed in both neoplastic and peritumoural stromal cells in different histopathology areas. METHODS: Patients who underwent primary tumour neck dissection for oral squamous cell carcinoma were included. Immunoexpression of MMP-1, -2, -3, -7, -9, -11, -13, and TIMP-1 and -2 in different areas of pathologic specimens (in situ carcinoma, primary tumour, invasive front, distant invasion carcinoma, and lymph node metastasis) was evaluated. Enzyme expression on mucosa adjacent to tumour served as control. RESULTS: Thirty cases were included. Only 6 MMPs and 1 TIMP were expressed in the studied areas. Statistically significant differences in the number of cases with positive MMPs or TIMP expression, in both neoplastic and peritumoural cells, between control and the rest of the areas were observed. MMP-2 expression was constant in the areas with a more aggressive biological behaviour. CONCLUSIONS: MMP-2 expression may represent a dynamic interaction between host and tumour that favours the establishment of neoplastic cells at distant sites.

Mutational analysis of K-ras and Ras protein expression in larynx squamous cell carcinoma.

The ras gene family (H, K and N-ras) encodes the Ras protein, a GTPase-activating protein that regulates several signal transduction pathways including cellular proliferation and differentiation. Mutations in codons 12, 13 and 61 of the ras genes constitute one of the most frequent alterations in human cancer. In the Western Hemisphere, a low frequency of mutations in these genes has been observed in head and neck carcinomas; a higher frequency has been found in countries such as India and Taiwan. Increased protein expression is a relatively frequent event in larynx carcinomas. This study was aimed to evaluate the participation of the k-ras gene and Ras expression in 20 Mexican patients with larynx squamous carcinoma, 2 with dysplasia and 4 with normal mucosa. Samples (of 26 patients) were embedded in paraffin and immunohistochemical analysis was performed for the Ras protein, as well as amplification of the k-ras gene exon 1 (108 bp) by laser capture microdissection. Then, DNA extraction, PCR and sequencing were performed looking for possible mutation in codons 12 and 13. All patients with larynx carcinoma were men, median age 62 years. Eighty-five percent of the patients had risk factors such as smoking and/or alcohol consumption, 25% were in clinical stages I and II, and 75% in stages III and IV; 45% of the patients presented tumor recurrence or persistence. In this study, no mutations were found in codons 12 or 13 of the k-ras gene; however, protein expression was observed in 95% of the samples and a higher expression of the protein was associated with tumor recurrence or persistence, although this was not statistically significant. Unexpectedly, well-differentiated carcinomas and dysplasias presented an increase in protein expression. These results suggest that ras may be involved in early stages of larynx carcinogenesis and may be activated by other mechanisms different from mutations, such as epigenetic events.

Tumores odontogénicos malignos. Estudio retrospectivo y colaborativo de 7 casos / Malignant odontogenic tumors. A retrospective and collaborative study of seven cases

Se presenta la frecuencia, características clínico-patológicas y evolución de los tumores odontogénicos malignos diagnosticados en tres servicios de patología de la Ciudad de México, de acuerdo a los criterios vigentes de la O.M.S. En total, se encontraron siete casos (5 en varones y 2 en mujeres), lo que representa menos del 4 por ciento de todos los tumores odontogénicos diagnosticados. Hubo seis carcinomas (dos ameloblastomas malignos, dos carcinomas odontogénicos de células claras, un carcinoma primario intra-óseo y un carcinoma originado del revestimiento de quiste odontogénico) y un fibrosarcoma ameloblástico. El intervalo de edad fue de 25 a 72 años (media: 43.8). Los carcinomas odontogénicos de células claras se presentaron en la región caninopremolar en maxilar y en mandíbula (un hombre y una mujer), mientras que el resto de lesiones se localizaron en la zona posterior de la mandíbula, con predominio por el sexo masculino (4:1), lo que concuerda con lo reportado en la literatura. El tratamiento en todos los carcinomas consistió en la resección quirúrgica, mientras que el fibrosarcoma fue tratado con quimioterapia debido a su gran extensión, sin respuesta favorable. El paciente con carcinoma primario intraóseo presentó metástasis submaxilar y cervical y la neoplasia fue causa de fallecimiento. A pesar de su rareza, los tumores odontogénicos malignos constituyen una causa importante de intervenciones quirúrgicas extensas en la región maxilofacial. (AU)