These findings demonstrate that both endothelium-dependent and endothelium-independent dilatation of the coronary microvasculature is impaired in syndrome X.

Transcutaneous electrical nerve stimulation can increase resting coronary blood flow velocity. The findings suggest that the site of action is at the microcirculatory level and that the effects may be mediated by neural mechanisms.

To establish the effectiveness of color Doppler ultrasound (US) in identifying flow in the intracranial venous system in newborns, 20 healthy, full-term newborns were scanned. Visualization of the subependymal and internal cerebral veins, superior sagittal sinus, vein of Galen, straight sinus, and left transverse sinus was accomplished in almost every newborn (greater than or equal to 90%). Mean blood flow velocities were as follows: subependymal veins, 3.0 cm/sec; internal cerebral veins, 3.3 cm/sec; inferior sagittal sinus, 3.5 cm/sec; vein of Galen, 4.3 cm/sec; straight sinus, 5.9 cm/sec; and superior sagittal sinus, 9.2 cm/sec. Flow in the subependymal and internal cerebral veins was continuous in all but one newborn (5%), while low-amplitude pulsations were observed with increasing frequency in the more central venous structures such as the vein of Galen (15%), straight sinus (32%), and transverse sinuses (36%). It was concluded that visualization of the intracranial venous system with color Doppler US is possible in the majority of healthy neonates.

Objectives-To assess the effect of hyperventilation and mental stress on coronary blood flow and symptom production in patients with syndrome X. Design-A prospective study. Hyperventilation and mental stress tests were performed on the ward and were repeated in the cardiac catheter laboratory where coronary blood flow velocity was also measured with an intracoronary Doppler catheter in the left anterior descending coronary artery. Oesophageal manometry studies were also performed. Patients-29 patients with syndrome X

This study examined the clearance of gastric acid from the oesophagus in ambulant patients with gastrooesophageal reflux. Eighteen patients with proved reflux disease were studied, nine with (group 1) and nine without (group 2) endoscopic oesophagitis. Oesophageal pressure and pH were recorded over 24 hours. Pressures were measured by a probe with five sensors: a 5 cm long sensor in the lower oesophageal sphincter, three sensors in the body of the oesophagus, and one at the pharynx to detect swallowing. Oesophageal pH was monitored 5 cm above the lower oesophageal sphincter. Manometric activities were classified as either peristaltic or ineffective. The latter included simultaneous, non-transmitted, and low amplitude peristaltic contractions. A reflux episode was defined as starting when pH fell to less than 4 and ending when the pH rose to 5. When the rise to pH 5 took place in three or more discrete steps after motor responses to gastrooesophageal reflux, the pH steps were labelled as initial change (I), middle changes (M), and last change (L). A total of 595 episodes of gastro-oesophageal reflux and 1626 associated motor events were analysed. Of these, 1331 (81-9%) were classed as primary peristaltic activity, 174 (10-7%) as primary ineffective activity, 46 (2.8%) as secondary peristaltic activity, and 75 (4-6%) as secondary ineffective activity. There were no significant differences in initial change (p>O05), middle changes (p>005), and last change (p>005) between group 1 and group 2. In all patients, the successive changes of pH in response to motor activity were significantly different (p=0-0001) between initial, middle, and last changes. Last change was significantly higher when compared with initial (p=0001) and middle changes (p<0001). Primary oesophageal peristalsis was the most frequent motor response to gastrooesophageal reflux. The last motor activity during reflux showed the greatest change in pH.