The human Prp8 protein is a component of both U2- and U12-dependent spliceosomes

This study reports the cloning, sequencing, and development of antisera against the human U5 snRNP 220-kDa protein or hPrp8p. Prp8p is the most highly conserved large nuclear protein known to date, but it is not related to any other protein. Southern, Northern, and expressed sequence tag analyses indicate that hPrp8p is encoded by a single gene. Prp8p is a core component of U5 snRNP and the U4/U6.U5 tri-snRNP, and antibodies raised against it immunoprecipitate both the major, U2-dependent and minor, U12-dependent spliceosomes. These spliceosomes, which excise different classes of introns, contain distinct sets of snRNAs overlapping only with U5 snRNA. Other than the core Sm proteins, hPrp8p is the first splicing factor shown to be common to both spliceosomes.

Echocardiographic estimation of critical left ventricular size in infants with isolated aortic valve stenosis

With the current trend to performing surgical valvotomy for infantile aortic stenosis without cardiac catheterization, there is a need to develop echocardiographic criteria for adequacy of left ventricular size. The echocardiograms and catheterization data of all 25 infants less than 3 months of age undergoing aortic valvotomy for isolated aortic valve stenosis from September 1980 through July 1990 were reviewed. Significant differences (p less than 0.05) between the survivors and nonsurvivors were noted for age at operation (30 +/- 28 vs. 3 +/- 1.5 days), mitral valve diameter (10.1 +/- 1.7 vs. 7.7 +/- 1.5 mm), left ventricular end-diastolic dimension (18.4 +/- 6.4 vs. 11.4 +/- 3 mm), left atrial dimensions (15.3 +/- 3.8 vs. 10 +/- 2.4 mm), left ventricular cross-sectional area on the parasternal long-axis echocardiogram (4 +/- 1.9 vs. 2 +/- 1.9 cm2) and angiographically determined left ventricular end-diastolic volume (43 +/- 23 vs. 11 +/- 5 ml/m2). There was no difference with respect to patient weight, body surface area, aortic root dimension or left ventricular ejection fraction. Left ventricular cross-sectional area less than 2 cm2 as measured on the parasternal long-axis echocardiogram was found in 5 of 7 nonsurvivors and 0 of 12 survivors, making this a risk factor for perioperative death (p less than 0.05). Left ventricular end-diastolic dimension less than 13 mm was found in 5 of 6 nonsurvivors and 2 of 17 survivors, making this another risk factor for early mortality (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Absence of left ventricular volume loading in infants with coarctation of the aorta and a large ventricular septal defect

Clinical characteristics and angiographic ventricular volume data were obtained in 25 infants aged 1 to 66 days who presented with coarctation of the aorta, ventricular septal defect and congestive heart failure to determine if left ventricular volume loading was present and if there were hemodynamic or volumetric variables that were predictive of operative mortality in this group. Pulmonary to systemic flow ratio averaged 2.8 +/- 0.8 and right ventricular/left ventricular peak pressure ratio was 0.96 +/- 0.12. Left ventricular end-diastolic volume averaged 116 +/- 49% of normal and was less than the investigators' lower limit of normal in 5 (20%) of 25 patients. In contrast, right ventricular end-diastolic volume, measured in eight patients, averaged 173 +/- 47% of normal and was greater than the investigators' upper limit of normal in seven (88%) of eight. Left ventricular ejection fraction averaged 0.47 +/- 0.17 and was below normal (less than 0.55) in 14 (58%) of 24 patients. Preoperative volume and ejection fraction data did not differ in infants with coarctation plus ventricular septal defect and a similar group of 19 infants with isolated coarctation. Abnormal left ventricular operative volume distensibility was inferred by normal or decreased left ventricular end-diastolic volume and increased left ventricular end-diastolic pressure (greater than 12 mm Hg) in 12 (55%) of 24 patients. Early plus late mortality was related to left ventricular size: 3 of 5 patients with a small left ventricular end-diastolic volume died, compared with only 4 of 20 with a normal or increased volume (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Coloplasty and free intestinal transplants in the treatment of extensive cancers of the pharyngo-oesophageal junction

The authors report their surgical experiences with 55 extensive tumours of the pharyngoesophageal junction. Thirty-three of these cases were managed by circular pharyngolaryngectomy, total oesophagectomy with stripping and left coloplasty, and 22 were treated with circular pharyngolaryngectomy with free intestinal transplants. A comparative study of the post-operative courses of the patients and their oncological and functional outcomes shows the advantages, disadvantages and indications of these two techniques.

Clinical assessment of ventricular function after surgical treatment of congenital heart defects

The assessment of ventricular function has contributed to the current surgical evaluation and surgical treatment of congenital heart defects, but many issues remain unresolved. The challenge of assessing ventricular function after surgical repair of congenital heart defects includes not only the general problem of distinguishing adverse loading conditions from myocardial failure but also more unique problems of right heart function and developmental differences in ventricular function. The possibility and significance of diastolic dysfunction are essentially unexplored and contingent upon our better understanding of the determinants of diastolic indices. Many of the technologies and methods are currently available and there is the beginning of a move toward better designed clinical trials and analysis of results. The assessment of ventricular function will become increasingly important as surgical techniques are improved and we are left with the more difficult choices between competing approaches.

Decreased early diastolic function after indomethacin administration in premature infants

The effect of indomethacin on systolic and diastolic cardiac function was assessed in 15 premature infants. Seven infants (group 1) received indomethacin to treat a clinically significant patent ductus arteriosus (PDA), and eight infants (group 2) received indomethacin prophylactically at 24 hours of age because of their high risk for PDA. Diastolic cardiac function was assessed using instantaneous rates of change of left ventricular (LV) cavity dimension, derived from M-mode echocardiography. The maximum velocity of lengthening of the LV cavity dimension, an index of early diastolic function, fell from 63 +/- 19 mm/sec before indomethacin to 48 +/- 16 mm/sec 1 hour after indomethacin in group 1 (P less than 0.01), with the ductus still patent and the LV chamber still dilated, and also decreased in group 2, from 52 +/- 7 mm/sec to 38 +/- 6 mm/sec (P less than 0.01). This index, when normalized for loading conditions, was decreased 1 hour after indomethacin at 12 +/- 2 sec-1 and 12 +/- 1 sec-1 for groups 1 and 2, respectively, compared with values before indomethacin of 15 +/- 3 sec-1 and 15 +/- 2 sec-1. There was no effect of indomethacin on the indices of systolic function. We conclude that indomethacin decreases early diastolic function in premature infants.

Detection of caval obstruction by magnetic resonance imaging after intraatrial repair of transposition of the great arteries

Vena caval obstruction may cause significant morbidity after intraatrial repair of transposition of the great arteries (TGA). Two noninvasive methods of diagnosing vena caval obstruction were compared with cardiac catheterization. Echocardiographically gated magnetic resonance imaging (MRI) and echocardiographic evaluation (2-dimensional saline contrast echocardiography and pulsed Doppler flow measurement) were performed on 15 patients 0.7 to 13.5 years after intraatrial repair of TGA (8 Mustard, 7 Senning). At catheterization, complete superior vena cava or partial caval obstruction (gradient greater than 5 mm Hg from cava to systemic venous atrium) was present in 7 of 15 patients. Superior vena cava obstruction was directly visualized by MRI in both patients with catheterization-proved complete superior vena cava occlusion. A dilated azygous/hemiazygous venous complex (greater than or equal to 5 mm cross-sectional diameter) was seen by MRI in 5 of 7 patients with complex or partial vena caval obstruction and in no patient without vena caval obstruction. MRI showed superior vena caval dilatation (ratio of superior vena caval diameter to aortic diameter greater than 1.45) in 3 of 5 patients with partial vena caval obstruction and in 0 of 8 without vena caval obstruction. Direct visualization of narrowing within the atrium was unreliable for any MRI plane because of the 3-dimensional nature of the intraatrial baffle. Two-dimensional saline contrast echocardiography, successfully performed in 12 of 15 patients, detected complete superior vena caval obstruction only in the 2 patients with catheterization-proved complete superior vena cava occlusion. Contrast echocardiography failed to identify any of the 5 patients with partial vena caval obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Altered early left ventricular diastolic cardiac function in the premature infant

Developmental changes in diastolic ventricular function were assessed in 31 premature infants and in 10 normal-term infants. They were studied during the first 72 hours of life using instantaneous rates of change of left ventricular (LV) cavity dimension, derived from M-mode echocardiography. Maximal velocity of lengthening of the LV cavity was significantly lower in premature infants (38 +/- 7 mm/s) than in term infants (88 +/- 15 mm/s). This variable increased with increasing maturity over the 4 gestational age groups evaluated (r = 0.87). This index normalized for instantaneous LV dimension was lower in the most immature infants (4.5 +/- 1 s-1) than in term infants (6.8 +/- 2 s-1). Eight of the premature infants were studied serially at 1, 3 and 7 days of age. Maximal velocity of lengthening divided by stroke dimension improved from 12.9 +/- 2 s-1 at 1 day of age to 16.5 +/- 3 s-1 at 7 days. These results suggest depressed early diastolic function in premature infants.