Biomedical subjects

M San Vicente

Publications and source records attributed to M San Vicente.

4 recordsLinked to original sources

PubMed1990

Spina bifida: a chick embryo experimental model.

Neural Tube Defects (NTD) can be induced in the chick embryo with relative ease in order to provide an experimental tool for investigation of such disabling malformations. Domestic hen (Gallus gallus) eggs were incubated at 37.5 degrees C and 80% humidity for 24 h. At that moment, 5 ml of albumen were aspirated by sterile puncture of the shell, and the incubation was resumed. The embryos were recovered and studied at the 8th, 10th and 14th days. Almost half (45%) of the 602 treated embryos survived and 73 of them (12%) had various malformations. Thirty-six (6%) suffered NTD of which 30 were open myelomeningocele, 2 meningocele and 4 encephalocele. The anatomy of the defects was astonishingly similar to that of the human malformation. Whether these experimental NTD are induced by mechanical or nutritional modifications of the internal environment of the egg is unknown, but the similarity of the lesion with those in humans make them suitable for further investigation of these issues. We believe that this relatively simple and inexpensive model is a suitable tool for research on spina bifida.

Animals↗

PubMed1990

[Experimental gastro-esophageal reflux in rats].

Aiming at developing a model of experimental gastro-esophageal reflux (GER) in the rodent we have tested three surgical procedures (distal esophageal myectomy (EM), esophago-gastrostomy (EG) and end-to-side esophago-jejunostomy (EJ) in three groups of 12 Wistar rats weighting 175 to 225 g. We have used for comparison a control group of unoperated rats. We have checked radiologically and by lower esophageal pH-monitoring that all three procedures induced GER and that this was absent in control animals. Six individuals in each group were sacrificed at the 7th day and the remaining six at the 14th day. At that time blood was drawn and esophageal tissue was collected for histological studies. Animals in the EM group were healthy after operation, had little vomiting and conserved their initial weight. Those in the EG and EJ groups had frequent vomiting, and lost weight. These symptoms were particularly severe in the EJ group. Animals in the control, EM and EG groups had histologically normal esophageal mucosa at the 7th and at the 14th days whereas those in the EJ group had grade 2-3 esophagitis at the 7th and grade 3 esophagitis at the 14th days. Esophageal epithelium in the rat is keratinized and therefore highly resistant to acid GER as attested by its excellent tolerance to reflux in the EM and EG groups. On the contrary, the presence of gastric and pancreatic juices and bile in the refluxate, like in the EJ group, digests the superficial layers of the epithelium and induces severe esophagitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗

PubMed1990

[Primary surgical pathology of the epiploon].

In the last nine years we have operated upon six children (eight males and two females) with primary omental pathology. The age of our patients ranged from five to eleven years with the exception of a newborn prenatally diagnosed of lymphangioma. All the remaining children had abdominal pain and right iliac tenderness for an average of two days. All had leukocytosis and left shift. Vomiting and fever were present only in one instance. In no case the mass was palpated preoperatively. The initial diagnosis was acute appendicitis in all cases. A patient suffered, one year after operation, a second acute clinical picture and the omental mass could be revealed [correction of decealed] preoperatively. At operation there was free intraperitoneal fluid in six instances (three times bloody, two times clear and one purulent). Surgical findings (nine operations) were: three omental segmental infarctions (primary in two cases and secondary to torsion in one), three segmental epiploitis in two patients (one acute, one chronic, one secondary to foreign body), two cystic lesions (one lymphangioma, one hydatic cyst) and one benign tumor (fibromatosis).

Child↗

PubMed1990

[Experimental malformations of the body wall in the chick embryo].

The rapidly growing possibilities of prenatal diagnosis and intrauterine manipulation of the malformed fetus have created the need for animal experimental models as simple and easy to handle as possible. We report on our experience with the induction of body wall defects in the chick embryo. Laparoschisis was produced by evisceration of the bowel through the umbilical stalk and its exposition to the allantoic fluid at the 14th day of incubation. Exomphalos, Cantrell's Pentalogy and Spina Bifida were induced by sterile aspiration of 5 ml of egg albumen at the 24th hour of incubation. All embryos were recovered and studied at the 19th day of incubation. The results can be summarized as follows: ninety-four (51%) of the 184 embryos operated for bowel exteriorization survived and 42 (45%) had intestinal lesions identical to those found in human laparoschisis. Two-hundred ans seventy (45%) of the 602 embryos treated by albumen extraction survived and 197 (73%) had no visible malformations, whereas either exomphalos or Cantrell's pentalogy were found in 37 (14%) and spina bifida was observed in the remaining 36 (13%). All lesions were strikingly similar to the human ones. These models could facilitate research on the above-mentioned malformations without the major difficulties and expenses inherent to fetal research in mammals. The chick embryo, for many decades a favorite model for embryologists, is a tool for fetal research as well and opens some perspectives in this field even for relatively modest laboratories.

Abdominal Muscles↗