Clonidine therapy for comorbid attention deficit hyperactivity disorder and conduct disorder: preliminary findings in a children's inpatient unit

This retrospective study examined the clinical course of 18 prepubertal boys (aged 6 to 12) who had dual diagnoses of attention deficit hyperactivity disorder and conduct disorder and who received clonidine on an inpatient basis after failed trials of conventional drug therapy, consisting predominantly of psychostimulants. The effects of clonidine were assessed during inpatient treatment and after discharge at intervals of 1 to 2 months. Eleven (61%) of the children had marked improvement as measured by clinical impression. Transient sedation lasting 2 to 3 days occurred after initial administration or dosage increase; otherwise, clonidine was well tolerated. Our findings suggest that clonidine may prove to be an alternative treatment of comorbid attention deficit hyperactivity disorder and conduct disorder.     

Structure of d(GT)n.d(GA)n sequences: formation of parallel stranded duplex DNA

Alternating polypurine sequences exhibit remarkable polymorphism. In this study, we report that dGA.dGT sequences form parallel stranded duplex DNA at neutral pH. Using two model hairpins, 3'-d(GT)3-5'5'-T4(AG)3-3' (I) and 3'-d(GT)4-5'5'-T4(AG)4-3' (II), containing 5'5' linkages which direct parallel strand formation, we systematically explored the spectroscopic and thermodynamic properties of parallel stranded d(GA)n.d(GT)n. The parallel stranded hairpins are remarkably stable structures with TM's of 41.5 and 47.5 degreesC (in 0.4 M NaCl) for the shorter and longer hairpins, respectively. The van't Hoff enthalpies of 80.7 and 114 kJ mol-1 are relatively low but are comparable to a parallel stranded d(GA)n duplex. On the basis of the spectroscopic and electrophoretic characteristics, we conclude that parallel strand formation is not restricted to hairpin systems, but also readily occurs in unconstrained dimeric duplexes with the appropriate sequence homologies. Both melting curves and electrophoretic analyses of parallel stranded heteroduplexes in which the sequence enforces specific base pairing demonstrate that G-G and A-T base pairs are formed in d(GA)n.d(GT)n segments.     

Pulmonary function test outcomes in healthy Navajo Native American adolescents

Prediction equations for estimating lung volumes have been determined for Caucasians, African-Americans, and Mexican-Americans. These separate equations were determined because of differences in thoracic morphology between people of various racial groups, making it impossible to use one prediction formula to accurately estimate lung volumes for all individuals. One hundred ninety-one adolescent Navajo children (males, n = 110; females, n = 81) between 11 and 18 yr of age volunteered for the study and underwent a series of pulmonary function tests (PFT). New pulmonary function prediction equations for Navajo youth were generated for estimating pulmonary volumes and capacities that more accurately predict expected PFT outcomes than formulas in common use for Caucasian, Mexican-American, or African-American youth.     

Open-heart correction of tetralogy of Fallot in an acyanotic dog

Tetralogy of Fallot was diagnosed in an acyanotic 11-month-old dog. Predicted pressure gradient across the pulmonic valve, as assessed by use of continuous wave Doppler echocardiography, was 94.5 mm Hg. Bidirectional shunting was identified by means of selective angiography. Open-heart correction was performed, using a transatrial approach with limited ventriculotomy and cardiopulmonary bypass. The hypertrophied infundibulum was resected, the ventricular septal defect was closed primarily, and a transannular pericardial patch graft was applied. Pressure gradients across the pulmonic valve were 52.9 and 22.8 mm Hg 2 weeks and 4 months after surgery, respectively. Advances in cardiopulmonary bypass, anesthetic management, and use of the transatrial approach may improve the success of open-heart correction of tetralogy of Fallot in dogs.     

Methionine transport by pig colonic mucosa measured during early post-natal development

New-born pig proximal colon, incubated in vitro, transports methionine with a Km of 0-33 mM and a Vmax of 0-62 mumole cm-2h-1. There is still a net transport of methionine on day 4, but the Km now increases to 10 mM and the Vmax falls to 0-15 mumole cm-2h-1. There is no net transport of methionine across proximal colons taken from 10-day-old pigs. 2. The mean intramucosal concentration of methionine, following incubation in medium containing 1 mM methionine, is 7-18+/-0-8 mM for the new-born, 0-55+/-0-05 mM for the 4-day-old and 0-31+/-0-06 mM for the 10-day-old pig. 3. Both methionine and glucose cause an immediate increase in the short-circuit current of new-born and 1-day-old pig colons. The kinetics for this interaction with methionine gives a Km for methionine of 0-24 mM and a maximum effect of 27 muA cm-2. This effect is not seen in 4- or 10-day-old pigs. 4. Net Na+ transport across the new-born pig proximal colon, measured in the absence of methionine, is about three times that calculated from the measured short-circuit current. Methionine increases the mucosal to serosal flux of Na+ by an amount roughly equal to that predicted from the increase in short-circuit current. The ability of glucose and methionine to affect short-circuit current is lost by day 4. 5. Short-circuit current, measured in the absence of methionine or glucose, increases between day 1 and 2 of post-natal life. This increased electrogenicity is maintained for up to at least 10 days after birth. 6. The pig proximal colon has many of the properties of a small intestine at birth. It actively transports methionine and the presence of methionine stimulates the absorption of Na+. These effects could be physiologically important in the pig, where the normal absorptive function of the intestine is temporarily inhibited at birth by the intestinal transmission of immune globulins.