Relationship of tracheal size to maximal expiratory airflow and density dependence.

Wave-speed theory predicts that maximal expiratory flow (MEF) at high lung volumes depends strongly on size of central airways. We tested this prediction by correlating MEF and tracheal cross-section area (T-XSA) in 15 (11 males, 4 females) healthy never-smoking volunteers. T-XSA was determined by planimetric analysis of contiguous 1-cm computerized tomographic scans of the intrathoracic trachea. We found a significant correlation between T-XSA at total lung capacity (TLC) and flow at 75% of vital capacity (V75) (r = 0.88, P less than 0.001). This contrasted to the correlation found between lung volume at TLC and V75 (r = 0.60). Density dependence of airflow (percent increase in V75 in air) was 35 +/- 17% and showed a significant inverse relationship to T-XSA (r = 0.70). These results confirm predictions of wave-speed theory and demonstrate the importance of cross-sectional area of central airways in determining MEF at high lung volumes. The large variability of MEF in normal individuals partly represents variations in tracheal size. Poor correlation between lung size and airway size suggests only a loose coupling between airways and lung parenchyma consistent with dysanaptic growth. Our findings indicate that changes in density dependence of airflow are not solely determined by the status of small airways and that differences in tracheal size contribute to its variability.

Rapid diagnosis of amniotic fluid embolism.

Acute respiratory failure developed in a 19-year-old primigravida 7 hours after undergoing cesarean section. The diagnosis of amniotic fluid embolism was established by viewing fragments of vernix caseosa in a pulmonary artery blood sample. Forty-eight hours after the cytologic diagnosis had been made, amniotic fluid material was no longer present in pulmonary arterial blood. The patient underwent supportive care in an intensive care setting and recovered completely.

Proteins of Epstein-Barr Virus. II. Electrophoretic analysis of the polypeptides of the nucleocapsid and the glucosamine- and polysaccharide-containing components of enveloped virus.

Two series of experiments were undertaken to identify the topological location of the structural polypeptides of Epstein-Barr virus. In the first series of experiments, nucleocapsids prepared by detergent treatment of enveloped virus with Nonidet P-40 and sodium deoxycholate were found to be composed of seven polypeptides, VP2, 6, 7.5, 24, 27, 31, ANd 33, which ranged in molecular weight from over 200 X 10(3) to 28 X 10(3). Nine other polypeptides, VP 4, 7, 8, 10, 15, 16, 23, 28, and 29, could be identified in preparations of Epstein-Barr virus nucleocapsids, but the relative amount of this second group of polypeptides was less in preparations of nucleocapsids than in preparations of enveloped virus. The incomplete removal of these polypeptides from enveloped virus by detergent treatment suggests that some of these polypeptides may be components of the envelope or tegument that lie in close proximity to the outer surface of the nucleocapsid In the second series of experiments periodic acid-Schiff-staining and glucosamine-containing components were identified with similar electrophoretic mobility to several of the polypeptides of enveloped virus (VP 5, 8, 9, 11, 12, 13, 14, 15, 16, 17, 28, and 29) that were completely or incompletely removed from purified virus preparations by detergent treatment. The similarity between the polypeptide composition of the nucleocapsids of Epstein-Barr virus and herpes simplex virus was in contrast to the dissimilarity between the nonnucleocapsid polypeptides of Epstein-Barr virus and herpes simplex virus.

Proteins of Epstein-Barr virus. I. Analysis of the polypeptides of purified enveloped Epstein-Barr virus.

Epstein-Barr virus (EBV) was purified from the extracellular fluid of HR-1 and B95-8 cell lines. The preparations of purified virus consisted of enveloped particles and had EBV-specific antigneic reactivity. Comparison of the amount of labeled protein in preparations of virus purified from cultures incubated in [35S]methionine with the amount of labeled protein in preparations obtained following a mixture of unlabeled virus with [35S]methionine-labeled cellular proteins indicated that less than 2% of the labeled protein in the purified virus preparation could be attributed to contamination with labeled cellular proteins. No extraneous membranous material was seen in thin sections of the purified virus preparations. Analysis of the polypeptides of purified enveloped EBV indicated the following. (i) Eighteen polypeptides could be resolved in Coomassie brilliant blue-stained electropherograms of extracellular virus purified from HR-1 and B95-8 cultures. (ii) Thirty-three polypeptides could be resolved in fluorograms of labeled EBV purified from B95-8 cultures and subjected to electrophoresis in acrylamide gels cross-linked with diallyltartardiamide. The molecular weight of the EBV polypeptides was estimated by co-electrophoresis with the polypeptides of purified herpes simplex virus and purified polypeptides of known molecular weight to range from 28 x 10(3) to approximately 290 x 10(3) (iii) The polypeptides of EBV could be grouped by their relative molar abundancy into three classes: VP6, 7, and 27 present in high abundance; VP1, 12, 20, 23, and 29 present in moderate abundance; and a third class of less abundant polypeptides, VP4, 5, 8, 9, 10, 11, 15, 16, 21, and 22. The remainder of the polypeptides could not be precisely quantitated. (iv) The polypeptides of purified EBV, although similar in number and in range of molecular weight to the polypeptides of purified herpes simplex virus, differ sufficiently from those of herpes simplex virus so as to preclude comparison of individual polypeptide components.