Self-expanding plastic stents for inoperable malignant strictures of the cervical esophagus.

Dysphagia and respiratory complications are the major problems in patients suffering from malignant strictures of the cervical esophagus. In inoperable cases, interventional palliation is the cornerstone of treatment. The aim of this study was to evaluate the use of self-expanding plastic stents (SEPS) in this group of patients. In a retrospective study, 23 patients suffering from various malignant obstructive diseases of the cervical esophagus, including squamous cell carcinoma (n = 10), laryngeal cancer (n = 7), lung cancer with esophageal invasion (n = 5), and metastatic breast cancer (n = 1), underwent SEPS placement, under endoscopic and fluoroscopic guidance. Tracheoesophageal fistula was documented in five patients. Technical success rate, improvement of dysphagia grade, and stent-related complications were evaluated after stent placement. Stent insertion was successfully achieved in all cases, namely in 20 patients at the first stent placement attempt and in three patients after a second attempt. Dysphagia grade was notably improved after 24 h. In two cases, major complications occurred. These were successfully treated without the need of stent extraction. Barium swallowing studies demonstrated complete sealing of all fistulas. Foreign-body sensation that gradually disappeared within the first week after stent placement was observed in eight patients. Recurrence of dysphagia occurred in three patients, due to hyperplastic tissue proliferation (n = 2) and tumor overgrowth (n = 1). Late migration of the stent was detected in one case after 67 days. SEPS placement is an effective and safe palliative treatment for malignant strictures of the cervical esophagus. Main advantages include easy retrievability and reduced rates of reinterventions.

Pelvic lymphocysts after radical hysterectomy and lymphadenectomy.

Five cases (5.5%) of lymphocysts were diagnosed and treated, among 80 type III modified radical hysterectomies performed for cervical cancer St. Ia2-IIa, in the last 6 years. Identification was initially made by palpation and confirmed by CT or US, in 4/5 cases in the first 2 postoperative months. Pelvic pain, fever and pressure symptoms were the most common clinical findings. A conservative approach was successful in 4/5 cases. Spontaneous regression was observed in one, while needle aspiration under radiologic guidance with (1/3) or without (2/3) tube insertion was applied in the rest. Conservative treatment failed in the last case presenting with a 12 cm cyst. An intestinal fistula developed, necessitating partial resection of the ileus and marsipulization. The complicated course of this patient's disease may indicate that a more aggressive treatment is warranted for large persisting cysts located in the irradiated field.

Acquisition and maintenance of autoshaped key pecking as a function of food stimulus and key stimulus similarity.

The results of a number of recent studies suggest that acquisitions of autoshaped key pecking in pigeons is affected by the similarity of the grain-hopper stimulus and response-key stimulus. In Experiment 1 this hypothesis was tested by training independent groups of pigeons to key peck under six different hopper-stimulus and key-stimulus similarity conditions, and three procedures containing either immediate reinforcement, variable delay of reinforcement, or omission of reinforcement for key pecking. Number of trials to acquisition was found to be related to the similarity variable. Maintained responding was affected by the response-reinforcer contingency. This effect was found both within and between subjects. Under two of the contingencies (automaintenance and omission), maintained responding continued to be affected by the similarity of the hopper stimulus and key stimulus. In Experiment 2 pigeons were given omission training with a hopper light on or off. Both acquisition and maintenance of key pecking were facilitated by the presence of the hopper light. The present findings suggest that much of the responding reported in various automatic shaping and training procedures may reflect the effects of key stimulus/food stimulus similarity.

The role of preliminary magazine training in acquisition of the autoshaped key peck.

A series of experiments tested the hypothesis that initial key pecks in the autoshaping procedure are generalized pecks at the illuminated grain hopper. Experiment I found that autoshaping readily occurred when the chamber was continuously illuminated by a house-light. In Experiment II, pigeons given magazine training and autoshaping with an unlighted grain hopper failed to autoshape in 200 trials. Acquisition of autoshaped key pecking was retarded in Experiment III when stimulus control by the magazine light was reduced. In the fourth study, pigeons were given magazine training with either a red or white magazine light and then given autoshaping with concurrently presented red and white keys. For all pigeons in this experiment, the first key peck occurred on the key of the same color as that pigeon's magazine light. The results of these experiments were interpreted as supporting an account of autoshaping that identifies initial key pecks as arising due to generalization of pecking at the lighted grain hopper to pecking at the lighted key.

Acquisition of the autoshaped key peck as a function of amount of preliminary magazine training.

Three experiments evaluated the effect of magazine training on acquisition of the pigeon's key peck during autoshaping. In Experiment I, pigeons were exposed to two days of extended magazine training, followed on the third day by keylight-only presentations. All pigeons pecked the keylight early in the keylight-only session. Experiment II examined the relationship between the number of magazine-training trials and trials to the first peck. Pigeons were given either 0, 3, 10, or 25 magazine-training trials followed by the standard autoshaping procedure. The number of trials to the first peck was related to the number of magazine-training trials. In Experiment III, pigeons were exposed to the standard autoshaping procedure without prior magazine training. The data from Experiment III suggested that key pecking will occur only after the response of eating from the lighted hopper has occurred. Taken together, these results suggest that initial magazine training is an important variable in autoshaping. Key pecking is discussed as a generalized consummatory response.