Diaphragm Pacing in Infants and Children

Since 1976 we have implanted bilateral diaphragm pacers in 34 infants and children: 26 with central hypoventilation syndrome (CHS), three with myelomeningocele, and five with quadriplegia. Compared to adults, several modifications have been necessary to achieve effective ventilation in infants and younger children. In all instances, a tracheostomy has been necessary due to impaired neuromuscular control of upper airway patency during pacing. Bilateral pacing has been necessary to achieve adequate ventilation; in the CHS children with normal awake ventilation, bilateral pacing during sleep eliminates the need for positive pressure ventilation. For the remaining children, adequate awake ventilation is achieved with bilateral pacing, thus permitting substantially greater mobility and limiting use of the ventilator to sleep time. Our longest survivor has now been paced for 10.7 years, and in no instance has phrenic nerve damage occurred secondary to electrical stimulation- Our current pacing regime is characterized by moderate respiratory rates (21 breaths/min), long interpulse intervals (95 ms), and short inspiratory times (0.6 sec), resulting in 50%-75% fewer stimuli/min compared to our previous regime. For all infants and children requiring 24-hour ventilatory assistance, our recent successes in maintaining ventilation using significantly fewer stimuli suggest that long-term continuous pacing is a realistic future goal.     

Variants of red cell ǵlucose-6-p-hosphate dehydroǵenase amonǵ Asiatic Indians

Among one hundfed and one unrelated Asiatic Indian males living in the Pacific north-west, five G-6-PD-deficient individuals were identified. The enzyme of three of these individuals was indistinguished elctrophoreticaly and biochemically from the Mediterranean type of deficiency. These individuals originated from the north-western parts of the Indian subcontinent. The enzyme of one individual and that of his subsequently studied beother (G-6-PD Kerala) was found to be simialr to G-6-PD Seattle by k_m G-6-P, k_m TPN, pH optimum, utilization of 2d-g-6P and Gal-6-P and electrophoretic migration rate in Tris buffer, pH 8.8. Electrophoresis on TEB buffer (pH 8.6) however, showed this variant to be different from G-6-PD Seattle, The desirability of using multiple electrophoretic methods in the elucidation of new variants is emphasized by these observations. The third abmormal G-6-PD (G-6-PD West Bengal) was unlike other mutations previously described in having higher-than normal k_m TPN and lower-than-normal k_m G-6-P and a slow electrophoretic mobilty. The identification of the Mediterranean type of G-6-PD deficiency in the north-western part of the Indian subcontinent, together with histrorical and molecular considerations, suggests affiinities of Mediterranean, Near Eastern, and North-west Indian populations.