Estandarización de la cuantificación de la concentración de hierro en el hígado por resonancia magnética / Standardization of the quantification of iron concentration in the liver by magnetic resonance imaging

Objetivo. Calibrar máquinas de RM de 1,5 teslas para la cuantificación de la concentración de hierro en el hígado. Material y métodos. En 28 RM de 1,5 teslas se ha analizado un fantoma con cuatro tubos con diferentes concentraciones de cloruro de hierro III y uno sin hierro, que reproduce a dos pacientes promedio con sobrecarga férrica moderada y alta con las secuencias de un modelo de cuantificación. Se midió para cada tubo la ratio de intensidad de señal con el tubo sin hierro y se calcularon los niveles de concentración teóricos en cada máquina según el modelo para los dos niveles de sobrecarga. Se compararon los resultados con los de la máquina de referencia en la que se habían diseñado el modelo y el fantoma, calculando la diferencia porcentual. Resultados. La diferencia porcentual media de las ratios con respecto a los del centro de referencia fue 11% (0,3-39). La media de los valores de concentración de hierro fue de 71μmol Fe/g para la sobrecarga media, y de 193μmol Fe/g para la sobrecarga alta. La diferencia porcentual media fue del 6% (1,2-37%) y 3,4% (0-16%) respectivamente. En dos máquinas se aplicó un factor de corrección de forma que la diferencia porcentual fue inferior al 25% en todos los casos. Conclusión. Se han calibrado 28 máquinas de 1,5 teslas para la cuantificación de la concentración de hierro en el hígado con una variabilidad menor del 25% (AU)

Objective. To calibrate 1.5 tesla magnetic resonance scanners for the quantification of the concentration of iron in the liver. Material and methods. We analyzed twenty-eight 1.5 tesla magnetic resonance scanners using a phantom with four tubes containing different concentrations of iron (III) chloride and one tube without iron. The phantom represented two typical patients: one with moderate iron overload and one with high iron overload. We measured the signal intensity ratio between each iron-containing tube and the tube without iron; then we calculated the theoretical levels of iron concentration in each scanner according to the model for the two levels of overload. We compared the results of each scanner with those of the reference scanner in which the model and the phantom had been designed, and we calculated the percentage of difference between the two scanners. Results. The mean difference in the ratios compared to the reference center was 11% (0.3-39). The mean concentration of iron was 71μmol Fe/g for moderate overload and 193μmol Fe/g for high overload. The mean difference was 6% (1.2- 7%) and 3.4% (0-16%). respectively. In two scanners, we applied a correction factor so that the difference was below 25% in all cases. Conclusion. We calibrated twenty-eight 1.5 tesla scanners for the concentration of iron in the liver and achieved variability less than 25% (AU)

[Standardization of the quantification of iron concentration in the liver by magnetic resonance imaging]. / Estandarización de la cuantificación de la concentración de hierro en el hígado por resonancia magnética.

OBJECTIVE: To calibrate 1.5 tesla magnetic resonance scanners for the quantification of the concentration of iron in the liver. MATERIAL AND METHODS: We analyzed twenty-eight 1.5 tesla magnetic resonance scanners using a phantom with four tubes containing different concentrations of iron (III) chloride and one tube without iron. The phantom represented two typical patients: one with moderate iron overload and one with high iron overload. We measured the signal intensity ratio between each iron-containing tube and the tube without iron; then we calculated the theoretical levels of iron concentration in each scanner according to the model for the two levels of overload. We compared the results of each scanner with those of the reference scanner in which the model and the phantom had been designed, and we calculated the percentage of difference between the two scanners. RESULTS: The mean difference in the ratios compared to the reference center was 11% (0.3-39). The mean concentration of iron was 71 µmol Fe/g for moderate overload and 193 µmol Fe/g for high overload. The mean difference was 6% (1.2- 7%) and 3.4% (0-16%). respectively. In two scanners, we applied a correction factor so that the difference was below 25% in all cases. CONCLUSION: We calibrated twenty-eight 1.5 tesla scanners for the concentration of iron in the liver and achieved variability less than 25%.

[Peutz-Jeghers syndrome associated with multiple epithelial tumors]. / Síndrome de Peutz-Jeghers asociado a múltiples tumores epiteliales.

The association between Peutz-Jeghers syndrome and multiple epithelial neoplasias is infrequent. Tumors of the gastrointestinal tract, genitals and breast are common in this syndrome and tumors of the kidney and biliary tract are exceptional. We present the case of a 68-year-old woman with Peutz-Jeghers syndrome who presented with right kidney carcinoma and numerous small, bilateral tumors of the sex cords with annular tubules of the ovary. Right nephrectomy, double annexectomy and total hysterectomy were performed. The patient died two years later following the development of rectal carcinoma diagnosed by sigmoidoscopy and biopsy and an episode of obstructive jaundice compatible with cholangiocarcinoma.

[Bleeding of the upper digestive tract due to gastric metastasis of squamous lung carcinoma]. / Hemorragia digestiva alta por metástasis gástrica de un carcinoma escamoso de pulmón.

Bronchogenic lung carcinoma, melanoma and breast cancer are the neoplasms which have most frequently been reported to metastasize to the stomach. These lesions are usually located on the fundus and on the upper part of the gastric body. They are usually asymptomatic with the diagnosis being made at necropsy. We present a patient who developed gastrointestinal bleeding as the first symptom of squamous lung cancer secondary to a gastric metastasis.

[Saliva in experimental gastroesophageal reflux]. / La saliva en el reflujo gastro-esofágico experimental.

Saliva, with a neutral pH, mucous content and inhibitory factors of the stomach acid secretion, can be considered a protecting element of the esophageal mucosa in the gastroesophageal reflux. 39 Wistar rats 175-225 g were used divided in seven groups: "C" control, "E-A" esophago-gastrostomy. "E-M" esophago-myectomy, "S-C" only sialoadenectomy, "S-EA" sialoadenectomy plus esophagogastrostomy, "S-EM" sialoadenectomy plus esophago-myectomy. 15 days later the rats were sacrificed, the esophagus was taken out for its histological examination and blood samples were drawn. The comparison between the control and treated groups, showed a significant deterioration of the EA, SEA and SEM groups regarding the final weight, and the SC group in the white series and ions. Many of the animals with esophagus operations showed vomit signs and general affectation. None of the groups showed esophageal lesions in the histology, from which it can be deduced that, in the rat, a 90% saliva absence doesn't produce negative effects on the esophageal mucosa either in acid presence or not.

[The experimental production of abdominal wall defects in the chick embryo]. / Producción experimental de defectos de la pared abdominal en el embrión de pollo.

We have developed experimental models of gastroschisis and celosomias (omphalocele and Cantrell's pentalogy) in the chick embryo. They were obtained by operation "in ovo" and early aspiration of 5 ml of egg albumin respectively. We have observed 42 gastroschisis out of 184 operated embryos and 12 exomphalos and 20 pentalogies out of 528 aspirated embryos. These models enable us to study the biology of malformed fetuses.

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.

[Primary surgical pathology of the epiploon]. / Patologia quirurgica primaria de epiplon.

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).

[Experimental malformations of the body wall in the chick embryo]. / Malformations expérimentales de la paroi du tronc chez l'embryon de poulet.

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.

[Experimental gastro-esophageal reflux in rats]. / Reflux gastro-oesophagien expérimental chez le rat.

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)