Chest radiograph changes after cardiopulmonary bypass in children

To determine the spectrum of pediatric chest radiograph changes after cardiopulmonary bypass, 98 children (mean age = 5.9 yr, range 4 wk-16 yr) were studied for 3 days postoperatively. Daily A-P radiographs were evaluated for atelectasis, cardiomegaly, pleural effusions, diaphragmatic elevation, mediastinal widening, and pulmonary infiltrates. The overall incidence of atelectasis was 82%, with left lower lobe atelectasis the most common (64%). Right upper lobe atelectasis occurred in 35% of patients, far more common than in the adult. Radiographic changes were then compared with independent variables including patient weight, age, duration of bypass, and fluid balance by multiple linear regression. Pleural effusion correlated with patient weight and duration of bypass. Diaphragmatic elevation correlated with patient weight. Cardiomegaly correlated with patient age. Net fluid balance was a poor predictor of postoperative chest radiograph changes. We conclude that radiographic changes are common after cardiopulmonary bypass in children, that the overall incidence is not markedly different from adults, and that right upper lobe atelectasis occurs more frequently in children.

Preoperative and postoperative "aneurysm" associated with coarctation of the aorta

The reported incidence of aortic aneurysm after surgical repair or balloon angioplasty for aortic coarctation varies widely. To determine the incidence of aneurysm formation after surgery, preoperative and postoperative cineangiograms from 65 patients who underwent operation at age 1.5 +/- 3.4 years were examined. Repair included a prosthetic patch in 14 patients, end to end anastomosis in 28 and subclavian flap in 23. Aneurysm was documented by change in contour or irregularities in contour at the repair site or by abnormal dimensions at the repair site, defined by the ratio of the widest measurement at the repair site to the measurement of the aorta at the diaphragm. An aneurysmal bulge above the ductus diverticulum was identified in 14 (23%) of 60 patients preoperatively; the area showed no change 4.72 +/- 4.07 years after surgery. Significant changes at the repair site were seen in only three patients, all of whom had Dacron patch repair. One patient had a change in contour at the repair site, one had an abnormally high repair site to diaphragmatic aorta ratio and one had a progressive increase in this ratio. Thus, during childhood years, 3 (5%) of 65 patients were diagnosed as having aneurysm at the surgical repair site. In conclusion, 1) comparison with preoperative cineangiograms, especially for aneurysmal bulges above the ductus arteriosus, is essential before an aneurysm can be attributed to coarctation repair by any technique, and 2) aneurysm developed only in patients subjected to Dacron patch repair.

Sequence and expression of potato U2 snRNA genes

Plant UsnRNA multigene families show a high degree of sequence variation among individual gene members. The potato U2snRNA gene family consists of between twenty-five and forty genes. Four potato U2snRNA gene variants have been isolated. Despite the sequence variation in coding and flanking regions, all maintain the conserved U2snRNA secondary structure and all contain the plant UsnRNA promoter elements: the upstream sequence element (USE) and TATA-like box in the -70 and -30 regions respectively. In RNase A/T1 protection analyses, one of the genes, PotU2-22, protected high levels of full length U2snRNA transcripts in potato leaf, stem, root and tuber RNA. Thus, PotU2-22 or genes with identical coding regions, are highly expressed in these potato organs and therefore represent a major subset of functional U2snRNA genes. Similar expression levels of the PotU2-22 sequence variant were also found in four genetically different potato cultivars and also in tobacco, a species closely related to potato, suggesting conservation of the coding regions of expressed U2snRNA genes. A second gene, PotU2-4, protected very low levels of full length transcripts while a third gene, PotU2-11, was not expressed in the potato organs analysed. The relative expression levels of the gene variants may reflect individual gene differences in, for example, the USE and TATA regulatory elements, or variations in gene copy number.

Pericardial drainage: subxiphoid vs. transthoracic approach

The optimal management of effusive pericardial disease remains controversial. Subxiphoid drainage has been criticized for a high recurrence rate while transthoracic procedures (window or pericardiectomy) are more invasive operations with greater potential for morbidity. We compared subxiphoid (SX group) and transthoracic (TT group) drainage in 131 patients (age range from 1 month to 81 years) treated from 1979 to the present. The etiology of effusion included cancer (38), uremia (24), infection (27), radiation (9), and other (33) causes. The two groups had similar age and sex distribution, etiology, and fluid volume. There was no difference in the operative mortality between the two groups (SX 15%, TT 13%, p = NS). Patients undergoing thoracotomy for treatment of effusive pericardial disease had a higher incidence of respiratory complications as defined by the presence of pneumonia, pleural effusion, prolonged ventilation, and need for reintubation (SX 11%, TT 35%, p less than 0.005). This may account, in part, for the longer mean hospital stay in transthoracic group (14.4 vs. 11.4 days). Nine patients were lost to follow-up after hospital discharge. The remaining 104 hospital survivors were followed for between 1 month and 11 years (mean 34 months, cumulative of 297 patient years). Three patients in each group experienced fluid recurrence and all but one were successfully treated by needle aspiration or percutaneous catheter placement. Following discharge, no patient required reoperation for effusive or constrictive pericardial disease or died from tamponade. There were no significant differences in 5-year actuarial survival (SX 54%, TT 49%) or actuarial freedom from recurrence (SX 89%, TT 93%).(ABSTRACT TRUNCATED AT 250 WORDS)

Prenatal development of the human nucleus ambiguus during the embryonic and early fetal periods

The ontogenetic development of the nucleus ambiguus was studied in a series of human embryos and fetuses ranging from 3 to 12.5 weeks of menstrual age (4 to 66 mm crown-rump length). They were prepared by Nissl and silver methods. Nucleus ambiguus neuroblasts, whose neurites extend towards and into the IXth and rostral Xth nerve roots, appear in the medial motor column of 4-6-week-old embryos (4.25-11 mm). These cells then migrate laterally (6.5 weeks, 14 mm) to a position near the dorsal motor nucleus of X. At 7 weeks (15 mm), nucleus ambiguus cells begin their migration, which progresses rostrocaudally, into their definitive ventrolateral position. The basic pattern of organization of the nucleus is established in its rostral region at 8 weeks (22.2-24 mm) and extends into its caudal region by 9 weeks (32 mm), when its nearly adult organization is evident. Cells having the characteristics of mature neurons first appear rostrally in the nucleus during the 8.5-9-week period (24.5-32 mm), gradually increase in number, and constitute the entire nucleus at 12.5 weeks (65.5 mm). Definitive neuronal subgroups first appear at 10 weeks (37.5 mm) in the large rostral nuclear region. These features suggest that the human nucleus ambiguus develops along a rostrocaudal temporospatial gradient. Evidence indicates that function of nucleus ambiguus neurons, manifested by fetal reflex swallowing, occurs after the cells migrate into their definitive position, establish the definitive nuclear pattern, and exhibit mature characteristics.

Effects of hypothermia on short latency somatosensory evoked potentials in humans

Short latency somatosensory evoked potentials (SSEPs) elicited by median nerve stimulation were monitored in 14 adult patients undergoing cardiac surgery under cardiopulmonary bypass and induced hypothermia. SSEPs were recorded at 1-2 degrees C steps as the body temperature was lowered from 37 degrees C to 20 degrees C to determine temperature-dependent changes. Hypothermia produced increased latencies of the peaks of N10, P14 and N19 components, the prolongation was more severe for the later components so that N10-P14 and P14-N19 interpeak latencies were also prolonged. The temperature-latency relationship had a linear correlation. The magnitude of latency prolongation (msec) with 1 degree C decline in temperature was 0.61, 1.15, 1.56 for N10, P14 and N19 components, respectively, and 0.39 and 0.68 for interpeak latencies N10-P14 and P14-N19, respectively. The rise time and duration of the 3 SSEP components increased progressively with cooling. Cortically generated component, N19, was consistently recordable at a temperature above 26 degrees C, usually disappearing between 20 degrees C and 25 degrees C. On the other hand, more peripherally generated components, N10 and P14, were more resistant to the effect of hypothermia; P14 was always elicitable at 21 degrees C or above, whereas N10 persisted even below 20 degrees C. The amplitude of SSEP components had a poor correlation with temperature; there was a slight tendency for N10 and P14 to increase and for N19 to decrease with declining temperature. Because incidental hypothermia is common in comatose and anesthetized patients, temperature-related changes must be taken into consideration during SSEP monitoring under these circumstances.

Psychology of time awareness

Mind transforms the continuance of physical space-time into moments (the absolute Now) and blends these moments into an apparent continuity through an overlapping of unfolding capsules. The flow of psychological time is an illusion based on the rapid replacement of these capsules. Each mind computes the measure of time passing and duration from the decay of the surface present in relation to a core of past events. As each new surface is generated, that surface, the rim of the immediate past, recedes in the wake of rising contents. This recession, an uncovering of phases latent in the original traversal, exposes layers in the past forming the content of the immediate past moment. The surge of the microgeny to a surface that dissolves the instant it appears, the priority of the Self in the unfolding sequence, the feeling of agency, create a Self in a state of becoming, a Self that travels in time like the crest of a wave, always in pursuit of a future just beyond the grasp of the present.

Fear of AIDS and attrition among medical technologists

Attitudes toward AIDS were measured by a survey of 212 attendees at the annual meeting of the New Jersey Society for Medical Technology. Twenty five percent of the respondents were considering leaving the profession because of a fear of AIDS. In addition, almost half would not have chosen the field knowing they would be handling HIV-positive samples. This high degree of concern may be an important factor contributing to the shortage of medical technologists.

Effects of dietary tyrosine on L-dopa- and amphetamine-induced changes in locomotor activity and neurochemistry in mice

Recent findings suggest that intraperitoneal injections of L-tyrosine at high doses (100 mg/kg) alters amphetamine-induced changes in behavior by restoring amphetamine-induced decreases in whole brain norepinephrine (NE). The present study examined the motor effects of L-dihydroxyphenylalanine (L-dopa) and d-amphetamine sulfate in mice after treatment with a basal casein diet supplemented with L-tyrosine. The basal diet supplemented with 1-4% L-tyrosine, or 1-4% L-phenylalanine, produced no changes in motor activity in otherwise untreated mice. Whereas L-dopa (25-100 mg/kg) following inhibition of extracerebral decarboxylase by Ro 4-4602 (25 mg/kg) slightly decreased activity in diet control (casein) animals, this drug treatment enhanced motor activity in a dose-related fashion when L-tyrosine was added to the diet. Increases in motor activity following low doses of amphetamine (0.75-1.5 mg/kg) in casein control mice were antagonized by dietary L-tyrosine, but a higher dose of d-amphetamine (3 mg/kg) interacted with the addition of L-tyrosine producing an increase in motor activity. Neurochemical changes observed in brain concentrations of tyrosine, dopamine (DA), norepinephrine (NE), dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), tryptophan, serotonin (5-HT) and 5-hydroxy-indoleacetic acid (5-HIAA) following drug and diet treatments suggest that 5-HT systems, in addition to catecholamine systems, may be involved in mediating these effects.

Semantic deterioration in Alzheimer's: the patterns to expect

Differentiating language changes between the normal aged and those in the early stages of dementia is never simple. Knowing the differences and what to expect can aid in making this diagnosis.

Cor triatriatum: clinical presentation and surgical results in 12 patients

Twelve patients with cor triatriatum have been seen at our institution since 1979. The clinical presentation, diagnostic evaluation, and surgical results are outlined in this retrospective review. Operation is the treatment of choice for this rare congenital cardiac defect. One patient died 1 day before scheduled operation, and 2 patients died postoperatively, yielding a surgical mortality rate of 17% and an overall mortality rate of 25%. Resection of the obstructing atrial membrane was performed using hypothermic cardiopulmonary bypass in all cases. Left atriotomy was performed in 6 patients, and right atriotomy was performed in 7. The two postoperative deaths occurred in patients who had serious associated cardiac defects. Associated anomalies include atrial septal defect, persistent left superior vena cava, and partial anomalous pulmonary venous return. The postoperative course has been excellent in all 9 surviving patients; all remain asymptomatic. Cor triatriatum is amenable to surgical repair with excellent results when diagnosed early and when not complicated by other severe cardiac anomalies.

Technical considerations and early results of sequential left internal mammary artery bypass grafting to the left anterior descending coronary artery system

The use of the internal mammary artery (IMA) as a coronary artery bypass graft conduit has recently been expanded to include sequential bypass grafting of multiple vessels. This has the theoretical advantage of allowing a greater percentage of myocardium to be revascularized with a conduit that has superior long-term patency rates. This article reviews technical considerations including maximizing IMA graft length and diameter, avoidance of an acute mediastinal or epicardial course, as well as anastomotic techniques for optimizing results of sequential IMA bypass grafting to the left anterior descending coronary artery system.

Symptomatic lower extremity deep venous thrombosis: accuracy, limitations, and role of color duplex flow imaging in diagnosis

Color duplex flow imaging (CDFI) permits pain- and risk-free direct imaging of the deep venous system of the lower extremities. To prospectively ascertain the accuracy and limitations of this technique, CDFI was performed in 75 lower limbs of 69 consecutive patients referred for venographic evaluation of clinically suspected lower extremity deep venous thrombosis (DVT). The CDFI study was obtained within 24 hours of the contrast venogram. Both studies were interpreted without knowledge of the patient's clinical findings or the results of the other test. Contrast venography was regarded as the standard for diagnosis of DVT. Accuracy was 99% for detection of DVT above the knee and 81% below the knee. Sonographic evaluation of the calf veins was technically adequate in 60% of limbs; accuracy was 98% in this group. In the 40% of limbs with technically limited CDFI studies of the calf, accuracy decreased to 57%. Although small nonocclusive thrombi occurred infrequently in this series of symptomatic patients, CDFI missed three of four such thrombi. It is concluded that CDFI, when not technically compromised, is sufficiently accurate to definitively diagnose symptomatic lower extremity DVT.

Genes encoding the 7S RNA and tRNA(Ser) are linked to one of the two rRNA operons in the genome of the extremely thermophilic archaebacterium Methanothermus fervidus

Analysis of gene structure in the extremely thermophilic archaebacterium, Methanothermus fervidus, has revealed the presence of a cluster of stable RNA-encoding genes arranged 5'-7S RNA-tRNA(Ser)-16S rRNA-tRNA(Ala)-23S rRNA-5S rRNA. The genome of M. fervidus contains two rRNA operons but only one operon has the closely linked 7S RNA-encoding gene. The sequences upstream from the two rRNA operons are identical for 206 bp but diverge at the 3' base of the tRNA(Ser) gene. The secondary structures predicted for the M. fervidus 7S, 16S rRNA, tRNA(Ala) and tRNA(Ser) have been compared with those of functionally homologous molecules from moderately thermophilic and mesophilic archaebacteria. A consensus secondary structure for archaebacterial 7S RNAs has been developed which incorporates bases and structural features also conserved in eukaryotic signal-recognition-particle RNAs and eubacterial 4.5S RNAs.

Effect of omental, intercostal, and internal mammary artery pedicle wraps on bronchial healing

Bronchial transection and devascularization is necessary in the course of sleeve resection or lung transplantation, leaving distal bronchial segments ischemic and subject to stricture or dehiscence. Thirty mongrel dogs underwent left lung autotransplantation. The bronchial anastomosis was wrapped with omentum (n = 9), intercostal muscle pedicle (n = 9), or internal mammary artery pedicle grafts (n = 6). Six control animals underwent bronchial anastomosis without an external wrap. Bronchial revascularization by capillary ingrowth from the pedicle to the bronchial submucosal plexus was demonstrated with all three types of vascular pedicle grafts; however, more consistent and confluent vascular ingrowth was provided by internal mammary artery pedicle grafts. Additionally, the bronchial anastomotic cross-sectional area was significantly better in the internal mammary artery group (84.5 +/- 3.3) as compared with that of the omental (68.4 +/- 8.3), intercostal muscle (66.9 +/- 10.9), or control groups (70.2 +/- 7.6). An internal mammary artery pedicle graft and the presence of dense confluent submucosal vascular ingrowth from any pedicle graft were independently predictive (p less than 0.05) of minimizing bronchial anastomotic narrowing. These data are consistent with previous findings suggesting that omental and intercostal muscle pedicle grafts promote early bronchial revascularization; moreover, the data demonstrate the superiority of an internal mammary artery pedicle graft to provide submucosal vascular ingrowth and to minimize anastomotic stenosis.

Congenital aneurysm of the left atrial wall in infancy

A 5-month-old male infant with congenital left atrial aneurysm is reported. The youngest patient previously reported was 2 1/2 years old. This case is unusual because the patient was an infant and because of the degree of mitral insufficiency and acute cardiac decompensation observed in the patient.

The tear resistance of various impression materials with and without modifiers

In this study, we measured the tear resistance of several commonly used impression materials. In the first part, a trouser-leg tear test was used to determine tear energies for 15 impression materials in three major groups (polysulfides, addition-reaction silicones, and polyethers). One brand of polysulfide demonstrated the highest tear resistance. In general, generic types of impression material could not be ranked according to tear energy. In the second part of the study, we measured the effect of the addition of a system modifier (retarder/thinner) on the tear resistance of four addition-reaction silicones and two polyethers. Retarder/thinners significantly reduced the tear resistance of five of the six materials tested.