Congenital anomalies of the gastrointestinal tract are a significant cause of morbidity in children and, less frequently, in adults. These abnormalities include developmental obstructive defects of the small intestine, anomalies of the colon, anomalies of rotation and fixation, anorectal anomalies, and intestinal duplications. Neonates with complete high intestinal obstruction do not usually require further radiologic evaluation following radiography, whereas those with complete low obstruction should undergo a contrast material enema examination. An upper gastrointestinal series must be performed in all patients with incomplete intestinal obstruction because management is different in each case. In low intestinal obstruction, ultrasonography (US) may help differentiate between small bowel obstruction and colonic obstruction. In addition, US can help correctly identify meconium ileus and meconium peritonitis and is useful in the diagnosis of enteric duplication cysts. In malrotation and anorectal anomalies, computed tomography (CT) and magnetic resonance (MR) imaging can provide superb anatomic detail and added diagnostic specificity. Intestinal duplications manifest as an abdominal mass at radiography, contrast enema examination, or US. At CT, most duplications manifest as smoothly rounded, fluid-filled cysts or tubular structures with thin, slightly enhancing walls. At MR imaging, the intracystic fluid has heterogeneous signal intensity on T1-weighted images and homogeneous high signal intensity on T2-weighted images. Familiarity with these gastrointestinal abnormalities is essential for correct diagnosis and appropriate management.
A wide spectrum of congenital anomalies may affect the upper gastrointestinal tract, including anomalies of the esophagus (e.g., atresia, fistulas, webs, duplications, vascular rings), stomach (e.g., congenital gastric outlet obstruction, duplications), and duodenum (e.g., atresia, annular pancreas, duplications, malrotation). The evaluation of affected patients can require multiple imaging modalities for diagnosis and surgical planning. Radiography is often diagnostic and specific and can usually provide important clues to help determine the optimal diagnostic procedure. Neonates with complete gastric or upper intestinal obstruction do not usually require further radiologic evaluation after radiography: Barium studies are usually contraindicated, and complementary procedures (e.g., ultrasound [US], computed tomography [CT]) are not usually helpful and may even delay surgery, resulting in death. Nevertheless, US has become important in the evaluation of the pediatric gastrointestinal tract and is being used in an increasing number of applications. CT and magnetic resonance imaging are unsuitable for general screening but provide superb anatomic detail and added diagnostic specificity. They are especially useful in demonstrating esophageal duplications and vascular rings as well as associated abnormalities. However, the decision to perform a given imaging examination should be considered carefully to avoid inconvenience or unnecessary radiation exposure to the patient or delays in surgical correction. Quality control programs should be in place to ensure safe, effective radiologic practice through use of up-to-date equipment and good imaging technique.
These data suggest that glutamatergic transmission could be involved in the maintenance of cocaine self-administration and in the early phases of abstinence.
Marijuana consumption during adolescence has been proposed to be a stepping-stone for adult cocaine addiction. However, experimental evidence for this hypothesis is missing. In this work we chronically injected male and female Wistar rats with either the cannabinoid agonist CP 55,940 (CP; 0.4 mg/kg) or its corresponding vehicle. Adult acquisition (seven 30 min daily sessions) and maintenance (fourteen 2 h daily sessions) of cocaine self-administration (1 mg/kg), food-reinforced operant learning under conditions of normal (ad libitum access to food), and high motivation (food-restriction schedule) were measured. Additionally, brain metabolic activity was analyzed by means of [ 18 F]-fluorodeoxyglucose positron emission tomography. During the acquisition phase, female CP-treated rats showed a higher rate of cocaine self-administration as compared to vehicle-treated females and males; no differences were found between both male groups. This effect disappeared in the maintenance phase. Moreover, no differences among groups were evident in the food-reinforced operant task, pointing to the cocaine-specific nature of the effect seen in self-administration rather than a general change in reward processing. Basal brain metabolic activity also changed in CP-treated females when compared to their vehicle-treated counterparts with no differences being found in the males; more specifically we observed a hyper activation of the frontal cortex and a hypo activation of the amygdalo-entorhinal cortex. Our results suggest that a chronic exposure to cannabinoids during adolescence alters the susceptibility to acquire cocaine self-administration, in a sex-specific fashion. This increased susceptibility could be related to the changes in brain metabolic activity induced by cannabinoids during adolescence.
The formulation and use of lime mortars with ceramic particles has, in the past, been a very common technique. Knowledge of such used techniques and materials is fundamental for the successful rehabilitation and conservation of the built heritage. The durability that these mortars have shown encourages the study of the involved mechanisms, so that they may be adapted to the current reality. The considerable amount of waste from old ceramics factories which is sent for disposal might present an opportunity for the production of reliable improved lime mortars. In this paper a number of studies that characterize old building mortars containing ceramic fragments are reviewed. The most important research undertaken on laboratory prepared mortars with several heat treated clays types is presented, specifically with incorporated ceramic waste.Some studies on the pozzolanicity of heat treated clays are examined and the heating temperatures that seem most likely to achieve pozzolanicity are presented. It was verified that some heating temperatures currently used by ceramic industries might correspond to the temperatures that will achieve pozzolanicity. Highlights: The use of air lime mortars with ceramics is well known from the past. Fine particles of heat treated clays have proven to be potentially pozzolanic. Repair mortars must have a behaviour similar to the ones already in place. Knowledge of old mortars is fundamental for the conservation of the built heritage. The use of ceramic waste in mortars has technical and environmental advantages.
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