Vascular rings and slings: long-term follow-up of pulmonary function.

Between 1968 and 1983, 54 patients underwent surgery for symptomatic aortic arch and pulmonary artery anomalies at St Christopher's Hospital for Children. Presenting symptoms included stridor, wheeze, apnea, recurrent pulmonary infections, or dysphagia. Diagnosis was established with chest roentgenogram, bronchoscopy, barium esophagram, and arteriography. Four types of vascular anomalies were encountered; double aortic arch (24 patients), right aortic arch with left ligamentum arteriosum (17 patients), anomalous innominate artery (10 patients), and pulmonary artery sling (three patients). There were no intraoperative deaths and only one postoperative death. All surviving patients had immediate relief of their severe respiratory or swallowing symptoms. Mild respiratory symptoms persisted postoperatively from 3 months to 4 years and included frequent or severe upper respiratory infections, persistent cough, stridor and pneumonia. Five of the 53 surviving patients were lost to follow up. The remaining 48 patients were followed from 6 months to 14 years and all but one patient noted complete resolution of all respiratory symptoms. Twenty-nine patients at follow up were old enough to undergo pulmonary function testing including vital capacity, functional residual capacity, and inspiratory and expiratory flow volume loops. Seventeen of these 29 asymptomatic patients consented to these studies, and nine of these patients had abnormal flow volume loops indicative of significant central airway obstruction; the other eight studies were normal. We conclude that surgical repair for vascular rings and slings is safe and symptomatically efficacious. However, anatomic tracheal or bronchial distortion persists in a significant number of these patients as evaluated by pulmonary function studies.

Improved extraction procedure for the assay of isosorbide-5-mononitrate in serum.

A procedure is described for the extraction of isosorbide-5-mononitrate from serum with diethyl ether-n-butyl acetate (15:1, v/v). After extraction, the diethyl ether is evaporated at room temperature and the nitrate remains dissolved in the relatively non-volatile n-butyl acetate phase. Glassware must be used throughout as the recovery of isosorbide-5-mononitrate is not reproducible when plastic tubes or plastic pipettes are used. The extraction recovery of isosorbide-5-mononitrate from serum is 67 +/- 7%, measured relative to external standards.

Isolation and physicochemical characterization of mitochondrial DNA from cultured cells ofPetunia hybrida.

Mitochondrial DNA ofPetunia hybrida was purified from cell suspension cultures. Up to 50% of the DNA could be isolated as supercoiled DNA molecules by CsCl-ethidium bromide density gradient centrifugation. The DNA purified from DNase-treated mitochondria bands at a single buoyant density of 1.760 gcm(-3) in neutral density gradients and runs on agarose gels as a single band with an apparent molecular weight exceeding 30 megadaltons (Md). Summing of the restriction endonuclease fragment lengths indicates a mitochondrial genome size of at least 190 Md. Electron microscopic analysis reveals the presence of a heterogeneous population of circular DNA molecules, up to 60 Md in size. Small circular DNA molecules, ranging in size from 2-30 Md are present, but unlike in cultured cells of other plant species they do not form discrete size classes and furthermore, they constitute less than 5% of the total DNA content of the mitochondria. The restriction endonuclease patterns of mitochondrial DNA do not qualitatively alter upon prolonged culture periods (up to at least two years).

Hemodynamic assessment of the Ionescu-Shiley pericardial xenograft in the mitral position.

While the very low thrombogenicity without anticoagulant therapy and generally good durability of the lonescu-Shiley bioprosthesis has been demonstrated, further hemodynamic assessment is necessary. The present study assessed cardiac function and heterograft performance during right and left heart catheterization at rest and exercise (three to six months postoperation) of eight patients with severe mitral stenosis and/or regurgitation prior to surgery. We found, comparing pre- and postoperative resting values, that mean pulmonary artery pressure decreased (32 +/- 2.7 to 22 +/- 3.5 mm Hg; P < 0.02), cardiac index increased (2.1 +/- 0.09 to 2.5 +/- 0.13 liters/min/m2; P < 0.01), pulmonary wedge pressure decreased (21 +/- 2.3 to 13 +/- 1.8 mm Hg; P < 0.01), and the clinical status (NYHA) improved markedly. Mean diastolic gradient across the pericardial xenograft was 6.1 +/- 1.1 mm Hg at rest and 14.6 +/- 2.3 mm Hg on exercise. The calculated xenograft surface area was 1.7 cm2 at rest and 2.0 cm2 during exercise. No regurgitation was detected in seven of eight patients. Thus, mitral lonescu-Shiley bioprosthesis provide excellent heterograft function.

A simple analytical test and a formula to predict the potential for dermal carcinogenicity from petroleum oils.

A correlation for predicting dermal carcinogenicity of petroleum oils in laboratory animals has been developed using two simple analytical tests. The tests are the Food and Drug Administration test (FDA) commonly used to measure white oil purity, and a viscosity test. In the correlation, FDA is a measure of aromaticity, and viscosity is used to account for molecular weight. The FDA test alone appears to be comparable to other predictors now in use, but incorporating viscosity significantly increases the accuracy of predicting dermal carcinogenicity. A formula is proposed, using both the FDA test results and viscosity, that predicts the percentage of mice which will develop neoplastic skin tumors.

Two potential Petunia hybrida mitochondrial DNA replication origins show structural and in vitro functional homology with the animal mitochondrial DNA heavy and light strand replication origins.

Four Petunia hybrida mitochondrial (mt) DNA fragments have been isolated, sequenced, localized on the physical map and analyzed for their ability to initiate specific DNA synthesis. When all four mtDNA fragments were tested as templates in an in vitro DNA synthesizing lysate system, developed from purified P. hybrida mitochondria, specific initiation of DNA synthesis could only be observed starting within two fragments, oriA and oriB. When DNA synthesis incubations were performed with DNA templates consisting of both the A and B origins in the same plasmid in complementary strands, DNA synthesis first initiates in the A-origin, proceeds in the direction of the B-origin after which replication is also initiated in the B-origin. Based on these observations, a replication model for the P. hybrida mitochondrial genome is presented.