Given an abstract, indicate which of the provided candidate titles (Option1 and Option2) best describes it (respond with the text of the title, not option1/2).

[Q]: Abstract: To test the hypothesis that occlusive apneas result from sleep-induced periodic breathing in association with some degree of upper airway compromise, periodic breathing was induced during non-rapid-eye-movement (NREM) sleep by administering hypoxic gas mixtures with and without applied external inspiratory resistance (9 cmH2O X l-1 X s) in five normal male volunteers. In addition to standard polysomnography for sleep staging and respiratory pattern monitoring, esophageal pressure, tidal volume (VT), and airflow were measured via an esophageal catheter and pneumotachograph, respectively, with the latter attached to a tight-fitting face mask, allowing calculation of total pulmonary system resistance (Rp). During stage I/II NREM sleep minimal period breathing was evident in two of the subjects; however, in four subjects during hypoxia and/or relief from hypoxia, with and without added resistance, pronounced periodic breathing developed with waxing and waning of VT, sometimes with apneic phases. Resistive loading without hypoxia did not cause periodicity. At the nadir of periodic changes in VT, Rp was usually at its highest and there was a significant linear relationship between Rp and 1/VT, indicating the development of obstructive hypopneas. In one subject without added resistance and in the same subject and in another during resistive loading, upper airway obstruction at the nadir of the periodic fluctuations in VT was observed. We conclude that periodic breathing resulting in periodic diminution of upper airway muscle activity is associated with increased upper airway resistance that predisposes upper airways to collapse.
Which is the apt title for the abstract? option1: Induction of periodic breathing during sleep causes upper airway obstruction in humans. option2: Standards for monitoring during anesthesia at Harvard [letter]
[A]: Induction of periodic breathing during sleep causes upper airway obstruction in humans.

[Q]: Abstract: A patient with severe chronic gastritis and duodenitis that clinically and endoscopically disappeared after an intestinal revascularization procedure is reported. Chronic intestinal ischemia appears to be a cause of gastritis as seen in this patient.
Which is the apt title for the abstract? option1: Chronic ischemic gastritis reversed after revascularization operation. option2: The long-term results of carotid endarterectomy for transient ischemic attacks.
[A]: Chronic ischemic gastritis reversed after revascularization operation.

[Q]: Abstract: The effects of electrical stimulation of the vagi on gas transport mediated by high-frequency, low tidal volume ventilation (HFV) was examined in 10 anesthetized, paralyzed, propranolol-treated dogs. Gas transport efficiency was estimated by measuring the rate of CO2 removed from the lungs (Vco2) achieved during 45-s bursts of HFV applied before (control 1), during, and after (control 2) electrical stimulation of the transected vagi. During vagal stimulation the heart rate was maintained by electrical pacing. During the 15-s phase of vagal stimulation pulmonary impedance increased from 3.6 +/- 0.7 to 6.2 +/- 2.2 cmH2O X l-1 X s, and Vco2 increased. When the electrical stimulation of the vagi was stopped, impedance and Vco2 returned to prestimulation values. Vco2 was always higher during electrical stimulation of the vagi when HFV of a fixed volume was applied over a range of frequencies or when a fixed oscillation frequency was used over a range of tidal volumes. The effects of vagal stimulation on HFV-mediated gas transport were quite similar to the effects of moving the locations of the bias flow inlet and outlet into the lung such that tracheal volume was decreased by 20 ml, an amount equivalent to estimated change in control airway volume thought to occur during vagal stimulation. We simulated the effects of vagal stimulation and decreased tracheal volume on Vco2 by using a previously described model of HFV-mediated gas transport.(ABSTRACT TRUNCATED AT 250 WORDS)
Which is the apt title for the abstract? option1: CO2 elimination by high-frequency oscillation: effects of vagosympathetic stimulation. option2: Trace elements in serum, packed cells, and dialysate of CAPD patients.
[A]:
CO2 elimination by high-frequency oscillation: effects of vagosympathetic stimulation.