Effect of general anesthesia in infancy on long-term recognition memory in humans and rats

Anesthesia in infancy impairs performance in recognition memory tasks in mammalian animals, but it is unknown if this occurs in humans. Successful recognition can be based on stimulus familiarity or recollection of event details. Several brain structures involved in recollection are affected by anesthesia-induced neurodegeneration in animals. Therefore, we hypothesized that anesthesia in infancy impairs recollection later in life in humans and rats. Twenty eight children ages 6-11 who had undergone a procedure requiring general anesthesia before age 1 were compared with 28 age- and gender-matched children who had not undergone anesthesia. Recollection and familiarity were assessed in an object recognition memory test using receiver operator characteristic analysis. In addition, IQ and Child Behavior Checklist scores were assessed. In parallel, thirty three 7-day-old rats were randomized to receive anesthesia or sham anesthesia. Over 10 months, recollection and familiarity were assessed using an odor recognition test. We found that anesthetized children had significantly lower recollection scores and were impaired at recollecting associative information compared with controls. Familiarity, IQ, and Child Behavior Checklist scores were not different between groups. In rats, anesthetized subjects had significantly lower recollection scores than controls while familiarity was unaffected. Rats that had undergone tissue injury during anesthesia had similar recollection indices as rats that had been anesthetized without tissue injury. These findings suggest that general anesthesia in infancy impairs recollection later in life in humans and rats. In rats, this effect is independent of underlying disease or tissue injury.

Monosodium glutamate stimulates secretion of glucagon-like peptide-1 and reduces postprandial glucose after a lipid-containing meal

BACKGROUND

Monosodium l-glutamate (MSG) is known to influence the endocrine system and gastrointestinal (GI) motility. The mechanism of postprandial glycemic control by food in the GI tract is mostly unknown and of great interest.

AIM

To investigate the effect of MSG on glucose homeostasis, incretin secretion and gastric emptying in humans after a lipid-containing meal.

METHODS

Thirteen healthy male volunteers (mean age, 25.5 years) and with no Helicobcter pylori infection were enrolled. A 400 mL (520 kcal) liquid meal with MSG (2 g, 0.5% wt:vol) or NaCl (control) was ingested in a single-blind placebo-controlled cross-over study. Blood glucose, serum insulin, plasma glucagon, plasma glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide were measured. Gastric emptying was monitored by a 13C acetate breath test. Postprandial symptoms were assessed on a visual analogue scale.

RESULTS

The 30-min postprandial glucose concentration was significantly reduced by adding MSG to the test meal. The area under the glucose concentration vs. time curve (0-60 min) was also significantly reduced by adding MSG (40.6 ± 3.51 mg·1 hr/dL with MSG vs. 49.2 ± 3.86 mg·1 hr/dL with NaCl, P = 0.047), whereas, the 30-min postprandial plasma GLP-1 level was significantly increased (58.1 ± 15.8 pmol/L with MSG vs. 13.4 ± 15.8 pmol/L with NaCl, P = 0.035). MSG did not affect the half gastric emptying time or postprandial symptoms.

CONCLUSIONS

Monosodium l-glutamate improved early postprandial glycaemia after a lipid-containing liquid meal. This effect was not associated with a change in gastric emptying, but was possibly related to stimulation of glucagon-like peptide-1 secretion.

Increase of weakly acidic gas esophagopharyngeal reflux (EPR) and swallowing-induced acidic/weakly acidic EPR in patients with chronic cough responding to proton pump inhibitors

BACKGROUND

Gastro-esophageal reflux disease (GERD)-related chronic cough (CC) may have multifactorial causes. To clarify the characteristics of esophagopharyngeal reflux (EPR) events in CC patients whose cough was apparently influenced by gastro-esophageal reflux (GER), we studied patients with CC clearly responding to full-dose proton pump inhibitor (PPI) therapy (CC patients).

METHODS

Ten CC patients, 10 GERD patients, and 10 healthy controls underwent 24-h ambulatory pharyngo-esophageal impedance and pH monitoring. Weakly acidic reflux was defined as a decrease of pH by >1 unit with a nadir pH >4. In six CC patients, monitoring was repeated after 8 weeks of PPI therapy. The number of each EPR event and the symptom association probability (SAP) were calculated. Symptoms were evaluated by a validated GERD symptom questionnaire.

KEY RESULTS

Weakly acidic gas EPR and swallowing-induced acidic/weakly acidic EPR only occurred in CC patients, and the numbers of such events was significantly higher in the CC group than in the other two groups (P < 0.05, respectively). Symptom association probability analysis revealed a positive association between GER and cough in three CC patients. Proton pump inhibitor therapy abolished swallowing-induced acidic/weakly acidic EPR, reduced weakly acidic gas EPR, and improved symptoms (all P < 0.05).

CONCLUSIONS & INFERENCES

Most patients with CC responding to PPI therapy had weakly acidic gas EPR and swallowing-induced acidic/weakly acidic EPR. A direct effect of acidic mist or liquid refluxing into the pharynx may contribute to chronic cough, while cough may also arise indirectly from reflux via a vago-vagal reflex in some patients.

High-viscosity liquid meal accelerates gastric emptying

Adding pectin to an elemental formula increases its viscosity through gelatinization, thus presumably preventing gastro-oesophageal reflux and aspiration pneumonia. We investigated the influence of the viscosity of an elemental formula on gastric emptying. Eleven healthy volunteers underwent three tests at intervals of >1 week. After fasting for >8 h, each subject received a test meal (enteral nutrition solution, enteral solution plus pectin, or water). Then gastric emptying (continuous (13)C breath test), gastro-oesophageal intraluminal pressures, oesophageal pH, and blood levels of glucose, insulin and gastrin were all measured simultaneously. The gastric emptying coefficient was significantly increased by adding pectin to enteral nutrition (3.01 +/- 0.10 vs 2.78 +/- 0.10, mean +/- SE, P < 0.05). The antral motility index was also significantly higher with pectin than without at 45-60 min and 60-75 min after the test meal (526 +/- 237 vs 6.5 +/- 4.6 mmHg s(-1) and 448 +/- 173 vs 2.3 +/- 2.3 mmHg s(-1) respectively; P < 0.05). Plasma glucose was significantly higher with pectin than without it at 60 min after ingestion (141.5 +/- 6.03 vs 125.8 +/- 4.69 microM mL(-1), P < 0.05). In healthy individuals, pectin increased the viscosity of enteral nutrition and accelerated gastric emptying.

Changes of in vivo gastrointestinal motor pattern in pacemaker-deficient (WsRC-Ws/Ws) rats

In vitro studies on pacemaker-deficient W-mutants have revealed a disappearance of rhythmic contraction in their gastrointestinal tracts. Their contractile force has not been diminished, however. In contrast, W-mutants often present dysmoility-like symptoms with distension of the gastrointestinal tract in vivo. Gastrointestinal motility of W-mutant rats was examined in vivo by an extraluminal strain-gauge force transducer method. We examined a normal gastrointestinal motor pattern in the rats with two distinct motor phases, digestive and interdigestive. Moreover, we detected a failure to form an interdigestive contractile complex in pacemaker-deficient rats. The interdigestive motor activity of the gastrointestinal tract is important for cleaning gastrointestinal tract in preparation for the next meal. The impairment of the interdigestive contractile complex may be related to the dysmoility-like symptoms of W-mutant rats in vivo.

The septal chondromucosal island pedicle flap: anatomic study and clinical application

A study was made of the facial regions of 10 fresh cadavers. The vascular anatomy of the perinasal region and the septum consistently confirmed the existence of a nasal alar basal artery and a nasal alar basal nerve to the septum. A new septal chondromucosal flap, supplied by the nasal alar basal artery and nerve, is proposed in this article. The composite flap can be used safely to restore partial or entire tarsoconjunctival defects of the upper or lower eyelid or combined defects of the upper and lower eyelid.

Effect of peptide YY on gastric motor and secretory activity in vagally innervated and denervated corpus pouch dogs

In this study, we examined the mechanism by which constant intravenous infusion of physiological doses of PYY affects gastric secretion and motility in the vagally innervated (Pavlov) and denervated (Heidenhain) corpus pouch. As a result, only in the Heidenhain pouch, PYY at a dose of 100 pmol/kg-h significantly inhibited gastric secretion in the interdigestive and postprandial states. A dose of 300 pmol/kg-h inhibited the gastric secretion in both types of pouch, but inhibition in the Pavlov pouch was less than in the Heidenhain pouch. The inhibitory effect of PYY on phase III contractile activity was dose-dependent and significant, except in the Heidenhain pouch, and no dose of PYY had any effect on postprandial gastric motility. After all, vagal denervation enhanced the inhibitory effect of PYY on gastric secretion, but abolished the inhibitory effect on phase III contractile activity. Our findings strongly suggest that the inhibitory effect of PYY on gastric secretion is in part mediated by a non-vagal pathway and the inhibitory effect of PYY on gastric motor activities is completely dependent on vagal innervation, but the vagus nerve acts as an inhibitory modulator of the inhibitory effect of PYY on gastric secretion.