Use of saliva in home monitoring of carbamazepine levels

Total carbamazepine (CBZ) levels in serum of 61 epileptic children were compared with saliva levels. Both resting and stimulated saliva was analyzed. The salivary levels were 38.6% of serum CBZ levels. A highly significant correlation was noted (r = 0.89, p < 0.001). Stimulation had no effect on saliva CBZ levels (r = 0.97). Salivary and serum CBZ levels were not affected by storing the samples for 7 days at room temperature. The data indicate that salivary CBZ may provide a reliable alternative monitoring method to Tegretol therapy, especially in children, in whom blood sampling is difficult. Furthermore, the samples may be collected at home and delivered to the laboratory by mail.

Parasympathetic autonomic neuropathy in diabetes mellitus: the heart is denervated more often than the pupil

In one hundred subjects with diabetes mellitus assessed by the techniques of power spectral analysis of heart rate variability and heart rate variability during deep breathing, parasympathetic (vagal) cardiac denervation was shown to occur approximately twice as commonly as parasympathetic pupillary denervation measured by the maximal velocity of pupillary constriction. The pupillary dysfunction was detectable only when both tests of cardiac innervation were abnormal as well. No correlation was found between any of the autonomic measures and duration of known diabetes or degree of metabolic control.

Vagal cardiovascular reflexes in young persons with syncope

OBJECTIVE

To study the neurocardiologic reflexes in young persons who have fainted under conditions of emotional stress.

DESIGN

Case-control study.

SETTING

Clinical neurophysiology laboratory in Haifa, Israel.

PATIENTS

Sixty persons (41 women and 19 men), 15 to 17 years old, who were referred for study because of syncope related to an emotionally distressing event. Forty aged-matched, healthy volunteers drawn from the same population served as controls.

MEASUREMENTS

Resting electrocardiogram, inspiratory-expiratory difference in heart rate during deep breathing, heart rate response to the Valsalva maneuver, and blood pressure during motionless standing for 5 minutes.

RESULTS

Although individual results were within widely accepted limits of normal, patients with syncope as a group had higher vagal autonomic tone than did controls. This manifested as a slower heart rate at rest (mean, 67.8 beats/min compared with 73.2 beats/min; P = 0.005), a higher inspiratory-expiratory difference in heart rate (mean, 44.1 beats/min compared with 37.9 beats/min; P = 0.001), and a higher Valsalva ratio (1.91 compared with 1.72; P < 0.0001). No significant difference was found in the PR and QTc (QT interval corrected for rate) intervals of the electrocardiogram or in the blood pressure response to standing.

CONCLUSION

Many young persons who faint under conditions of emotional distress do so because a relatively high vagal tone predisposes them to the cardioinhibitory component of the syncope. Age-related physiologic reduction in vagal cardiac responses may explain the lower incidence of this type of syncope with increasing age.