Effects of ouabain on respiratory rhythm generation in brainstem-spinal cord preparation from newborn rats and in decerebrate and arterially perfused in situ preparation from juvenile rats.

The significance of Na/K-ATPase on respiratory rhythm generation is not well understood. We investigated the effects of the Na/K-ATPase blocker, ouabain, on respiratory rhythm. Experiments were performed with brainstem-spinal cord preparation from 0 to 3-day-old Wistar rats and with decerebrate and arterially perfused in situ preparation from juvenile rats (postnatal day 11-13). Newborn rat preparations were superfused at a rate of 3.0 ml/min with artificial cerebrospinal fluid, equilibrated with 95% O2 and 5% CO2, pH 7.4, at 26-27 °C. Inspiratory activity was monitored from the fourth cervical ventral root (C4). Application of ouabain (15-20 min) resulted in a dose-dependent increase in the burst rate of C4 inspiratory activity. After washout, the burst rate further increased to reach quasi-maximum values under each condition (e.g. 183% of control in 1 µM, 253% in 10 µM, and 303% in 20 µM at 30 min washout). Inspiratory or pre-inspiratory neurons in the rostral ventrolateral medulla were depolarized. We obtained similar results (i.e. increased phrenic burst rate) in an in situ perfused preparation of juvenile rats. Genes encoding the Na/K-ATPase α subunit were expressed in the region of the parafacial respiratory group (pFRG) in neonatal rats, suggesting that cells (neurons and/or glias) in the pFRG were one of the targets of ouabain. We concluded that Na/K-ATPase activity could be an important factor in respiratory rhythm modulation.

Food residue at endoscopy in patients who have previously undergone distal gastrectomy: risk factors and patient preparation.

BACKGROUND AND STUDY AIMS: Food residue is often seen in the gastric remnant after partial gastrectomy, making it difficult to diagnose early cancer in the residual stomach. The aims of this study were to clarify the risk factors for the accumulation of food residue, and to study methods of preparation for endoscopy in patients who had undergone distal gastrectomy. PATIENTS AND METHODS: 374 endoscopic examinations of patients who had undergone distal gastrectomy for gastric cancer were compared with 2168 endoscopic examinations in patients without a history of gastrectomy. Relationships between the presence of food residue and a number of clinical factors, including patient preparation, were evaluated by univariate and multivariate analyses. RESULTS: Food residue in the gastric remnant was observed in 70 examinations (18.7 %), a significantly higher proportion than that found in control patients (0.3 %). From multivariate analysis, underlying diseases (endocrine, metabolic, or connective tissue disease), Billroth type I reconstruction, and postoperative gastric retention were found to be independent risk factors for the accumulation of food residue. Diet preparation (a liquid diet plus aclatonium napadisilate) significantly decreased the incidence of food residue. CONCLUSIONS: Our diet preparation method can be recommended as a preparation for upper gastrointestinal endoscopy in patients who have undergone distal gastrectomy, especially in patients with additional risk factors.