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Biomedical subjects

L Reid

Publications and source records attributed to L Reid.

At least 19 recordsLinked to original sources
PubMed1979

Ultrastructural features of the distended pulmonary arteries of the normal rat.

Detailed study has been made of the structure of the normal pulmonary artery of rat by both light (1-micrometer sections) and electron microscopy. After tying the pulmonary veins at the hilum, the lungs were fixed by simultaneous injection of glutaraldehyde into the pulmonary trunk and trachea. Study of distended arteries allows precise measurement and assessment of normal lung structure. Four regions of the pulmonary artery can be identified by wall structure and are described here--muscular, partially muscular, non-muscular and the newly described thick-walled oblique muscular. Electron microscopid examination has demonstrated in the non-muscular regions of the partially muscular arteries, an "intermediate" cell and in the non-muscular arteries, a pericyte. The intermediate cell lies internal to the single elastic lamina but external to the endothelial cell, is surrounded by its own basement membrane and contains filaments mainly along the adluminal region of the cell. The pericyte also lies internal to the single elastic lamina, is within the basement membrane of the adjacent endothelial cell and has previously been reported in the lung only in the walls of alveolar capillaries. The structure of the intermediate cell and its position suggest it is a transitional stage between the pericyte and smooth muscle cell.

Animals↗
PubMed1979

Unusual vascular anomalies causing persistent pulmonary hypertension in a newborn.

A unique case of pulmonary vascular anomalies causing persistent pulmonary hypertension in a newborn is described. The child died 3 days after birth. Necropsy revealed marked hypoplasia of the right and left pulmonary arteries with a normal main pulmonary artery, patent ductus arteriosus, bilateral systemic arteries to the lungs from the abdominal aorta, and partial anomalous pulmonary venous connection. Quantitative morphometric techniques demonstrated slight abnormalities of alveolar development and severe arterial medial hypertrophy with abnormal extension of muscle into small peripheral arteries. Bronchopulmonary development appeared relatively normal in spite of the vascular abnormalities.

Angiocardiography↗
PubMed1979

Bronchopulmonary dysplasia--pathology.

The term bronchopulmonary dysplasia has much to commend it. It does not declare the etiology of this disease, which seems to be an advantage. Another advantage is that it presents the idea of disturbance of growth as well as scarring. The premature lung responds at birth somewhat differently from the mature lung, not just in respect to surfactant but from the point of view of the blood vessels' size and compliance. But treatment must also be considered. The administration of steroids to the mother in the antenatal period probably favors maturation in the fetus, rather than growth of size and cell multiplication, which will also influence the behavior of the lung postnatally. This is probably a critical feature to look for in clinical assessment and follow-up of these patients.

Humans↗
PubMed1979

Children's judgments of utterance appropriateness.

Judgments of utterance appropriateness were examined in 3-, 4-, 5-, and 6-year olds to examine the bases for these judgments in a variety of social contexts. The results indicated that the 4- and 5-year olds based their judgments in part on factors such as the available nonlinguistic evidence supporting the utterance and the types of evaluative terms used in the utterance. The judgments of the 6-year olds more closely resembled those of a group of adults, but their judgments were not yet free of some of the factors operative for the younger children. The findings are discussed in terms of the illocutionary and conversational characteristics of the stimulus utterances.

Adult↗
PubMed1979

The lungs in congenital bilateral renal agenesis and dysplasia.

A detailed quantitative analysis was made of the lungs from 8 infants dying with bilateral renal agenesis or dysplasia. Total lung volume was reduced in all cases, particularly in those with renal agenesis. In both groups there was a reduction in number of airway generations, indicating interference with development at between 12 and 16 weeks' gestation. The alveoli in each acinus were reduced in size and, in some cases, number--although their stage of differentiation was normal for age--pointing to a disturbance of growth during later fetal life also. As liquor is largely non-renal in origin at least up to 16 weeks' gestation, it seems that there are factors other than the oligohydramnios interfering in early lung growth in these cases, such as reduced proline production by the kidney.

Bronchi↗
PubMed1979

Structural alterations to the pulmonary circulation in fulminant hepatic failure.

Like patients with chronic liver disease, those with coma due to fulminant hepatic failure may show arterial hypoxaemia even in the absence of pulmonary complications, and in both it is attributed to increased intrapulmonary arteriovenous admixture. This study is concerned with the structural alterations in the pulmonary circulation of patients who have died from fulminant hepatic failure. Precise quantitative morphometric techniques applied to the injected and inflated lung have shown the major abnormality to be a diffuse dilatation of the pulmonary vascular bed affecting arteries and veins of all structural types. At an intra-acinar level the diameter of arteries accompanying respiratory bronchioles was 232.97 micron (+/-SD 46.35) compared with 177.76 micron (+/-SD 30.43) in controls (P less than 0.01). In two-thirds of the patients pleural spider naevi were seen and, throughout the lung, similar significant dilatation of precapillary vessels; but in only one patient were precapillary anastomoses shown. While intrapulmonary venous admixture undoubtedly contributes to hypoxia in fulminant hepatic failure, its exact relation to the structural changes is not yet determined.

Adolescent↗
PubMed1979

Bronchorrhoea--separation of mucus and serum components in sol and gel phases.

Bronchorrhoea sputum separates into two phases--sol and gel--at low speed centrifugation (5000 g), although higher speed (160 000 g) is required to obtain complete separation. Markers of mucus glycoprotein and serum transudate have been estimated in sputum, sol, and gel in five cases of bronchorrhoea associated with chronic bronchitis, asthma, or alveolar cell carcinoma. In all samples markers of both mucus glycoprotein and serum component were present in each phase. The concentration of serum markers was similar in both phases suggesting that it is to the serum that mucus glycoprotein is added. Since the volume of sol is greater, the total of serum components is higher in the sol than in the gel although, in total, a considerable amount was present in the gel. The fucose/sulphate ratio suggests that the glycoprotein in the sol is relatively more sulphated than is that of the gel, indicating that they may represent secretion from different cell types. The pattern of separation of two serum markers, IgA and transferrin, is different from that of albumin. Whether this is because they are locally produced or because they are selectively bound to mucus glycoprotein in the gel is not clear.

Adult↗
PubMed1979

Thallium-201: quantitation of right ventricular hypertrophy in chronically hypoxic rats.

Sprague Dawley rats were divided into two groups. Ten were kept in room air and 10 in hypobaric hypoxia (air at 380 mm Hg). After two weeks all were injected intravenously with 50 muCi of 201Tl and sacrificed. The right and left ventricles were separated, weighed, and measured for radioactivity in a gamma well counter. Left and right ventricular mass ratios (MR) correlated with 201Tl radioactivity ratios (TAR) in both control and hypoxic rats: r = 0.962 where MR = 0.863 TAR + 0.27. Myocardial 201Tl uptake reflects and quantitates normal and abnormal ventricular mass, the abnormal mass in this model consisting of right ventricular hypertrophy associated with hypoxic pulmonary hypertension.

Animals↗
PubMed1979

Rat pulmonary circulation after chronic hypoxia: hemodynamic and structural features.

In 55 Sprague-Dawley rats (mean wt, 277 +/- 6.2 g) exposed to hypobaric hypoxia (air at 380 mmHg), and 23 weight-matched controls kept in room air, pulmonary and systemic artery pressures were measured daily for 2 wk via indwelling catheters. After each day of exposure, 1 or 2 hypoxic rats, to a total of 20, and 5 control rats were killed during the experiment. In these rats, the pulmonary arterial tree was injected post mortem with barium-gelatin and inflated with formaldehyde solution, and three structural features were quantified microscopically: 1) abnormal extension of muscle into peripheral arteries where it is not normally present (EMPA); 2) increased wall thickness of the normally muscular arteries, expressed as a percentage of external diameter (%WT); and 3) reduction in artery number expressed as an increase in the ratio of alveoli to arteries (A/a). Mean pulmonary artery pressure (Ppa) rose significantly after day 3 of hypoxic exposure (P less than 0.05) and had doubled by day 14; the mean systemic artery pressure (Psa) of hypoxic rats and Ppa and Psa of control rats were unchanged. The level of Ppa correlated with the degree of structural changes; for EMPA, r = 0.84; for %WT, r = 0.64; and for A/a, r = 0.73 (P less than 0.001 in all.

Animals↗
PubMed1979

Development of pulmonary arterial changes in rats fed Crotalaria spectabilis.

The early changes in pulmonary artery structure and the timing and development of right ventricular hypertrophy were examined in rats after ingestion of Crotalaria spectabilis; the arteries were distended with a Micropaque--gelatin mixture. The earliest change, detected at Day 3, is the appearance of new muscle in normally nonmuscular arteries. Increased medial wall thickness of the normally muscular arteries is apparent from Day 7, reaching significance in the smaller arteries from Day 10 and in the larger arteries from Day 14. A reduction in number of small, filled peripheral arteries is apparent at Day 14 and is significant at Day 21 as is the increase in the ratio of alveoli to arteries per unit area of section. Right ventricular hypertrophy is detected and significant at Day 21 and, like all the arterial changes, continues to increase to Day 35. Hypoxia produces similar changes to those described above, although without the inflammation seen after Crotalaria ingestion, but the time table is different. New muscle appears in both models at the same time, but the other changes appear more slowly after ingestion of Crotalaria spectabilis.

Animals↗
PubMed1979

Beta-agonists and secretory cell number and intracellular glycoproteins in airway epithelium. The effect of isoproterenol and salbutamol.

This study describes the effect of systemic administration of the beta-adrenergic agonists isoproterenol and salbutamol on the secretory cell populations in seven regions of rat airway epithelium (three extrapulmonary and four intrapulmonary) and on the size of salivary glands and heart. Isoproterenol (a nonselective beta-adrenergic agonist) significantly increases secretory cell number in all airway regions except the midtrachea; salbutamol (a selective beta 2 agonist) increases secretory cell number only in proximal and peripheral regions. The absolute number of secretory cells is greatest in the most peripheral region after isoproterenol administration and in the most proximal region after salbutamol, although both drugs produce the greatest relative increase at the periphery. In proximal and, particularly, peripheral regions, the increase by isoproterenol (less than 3- and 14-fold, respectively) is greater than by salbutamol (less than 2- and less than 3-fold, respectively). In all airway regions, both drugs modify intracellular glycoprotein in the secretory cell population; within a given region, modification is much the same. In the most proximal region, the population of cells synthesizing only granules of neutral glycoprotein significantly increases while in other regions increase is in cells synthesizing only granules of acid. A significant shift in glycoprotein synthesis occurs whether or not the secretory cell population is increased, which suggests that existing as well as newly appearing cells modify their product. Isoproterenol significantly increases the size of the parotid and submaxillary glands; salbutamol increases the size of the parotid only. Isoproterenol significantly increases the weight of both ventricles of the heart; salbutamol has no such effect.

Adrenergic beta-Agonists↗
PubMed1979

Hypersecretion of mucus glycoproteins in rat airways induced by tobacco smoke.

An animal model of chronic bronchitis has been produced in vivo by exposing rats for 6 weeks to tobacco smoke: the laryngeal and tracheal glands have been studied in vitro by organ culture to analyze glycoprotein precursor incorporation and glycoprotein secretion by individual cells, a feature not previously studied. In the hypertrophied glands produced by tobacco smoke exposure, the cellular rate of glycoprotein secretion was increased. The in vivo administration of phenylmethyloxadiazole (PMO) to rats exposed to tobacco smoke blocked this effect. In vitro analysis of glands from unexposed rats that received PMO showed that it modified cell function directly by reducing the rates both of glycoprotein discharge and or precursor incorporation into intracellular glycoproteins.

Animals↗
PubMed1979

Increased muscularity of the pylmonary circulation in victims of sudden infant death syndrome.

It has recently become apparent that some victims of sudden infant death syndrome (SIDS) are chronically hypoxemic before death. In this study, the structural alterations in the pulmonary circulation of 15 victims of SIDS were examined using precise quantitative morphometric techniques applied to the injected and inflated lung. Increased muscularity of the pulmonary circulation has been demonstrated, as evidenced by the extension of muscle into arteries not usually muscularized during the first year of life, and by an increased thickness of the medial wall in some patients. This confirms the findings of Naeye and further justifies the shift of investigative efforts from the events immediately surrounding death to a search for chronic abnormalities.

Humans↗
PubMed1979

Hypoxia and incorporation of 3H-thymidine by cells of the rat pulmonary arteries and alveolar wall.

In the pulmonary arterial circulation hypoxia produces increase in thickness of the medial muscle coat as well as of the adventitia; in addition muscle appears in smaller arteries than is normal and the number of small arteries that fill on Micropaque-gelatin injection is reduced. To assess the role of hyperplasia in these changes, the uptake of 3H-thymidine by the cells of the pulmonary arterial wall has been studied in rats exposed to hypobaric hypoxia (exposure to 380 torr) after 1, 3, 5, 7, 10, and 14 days. Using autoradiographs of 1-micron sections, the glutaraldehyde-distended intrapulmonary hilar muscular artery, the peripheral, intraacinar arteries less than 100 micron in external diameter, and the alveolar wall had different patterns of uptake. In the hilar pulmonary artery, after 24 hours of exposure, the labeling index for adventitial fibroblasts is increased eightfold over the control value, and for endothelial cells, threefold, while for medial smooth muscle cells, there is a gradual and small increase to Day 14. Newly muscularized intraacinar arteries are first apparent at Day 3, when they comprise 40% of the intraacinar arteries, increasing to 80% at Day 7. No decrease in density of arteries is found. Uptake of 3H-thymidine by new muscle cells is not apparent until Day 5 when labeling is maximum. The endothelial cells of the newly muscularized arteries show an increased labeling index only at Days 7 and 10. The veins and normally muscular arteries do not show these changes. In the alveolar walls, the concentration of labeled cells is significantly above the control value at Days 3, 5, and 7 and significantly below, at Day 14. At this level, the interstitial, epithelial, and endothelial cells contribute to the increase.

Animals↗
PubMed1979

Aorta-pulmonary shunts in growing pigs. Functional and structural assessment of the changes in the pulmonary circulation.

Aorta-pulmonary shunts were produced in growing pigs, 4 to 12 weeks of age, by anastomosing the thoracic descending aorta to the pulmonary trunk, and the animals were followed for periods of 1 to 3 months. Correlation between the hemodynamic findings and the lung structure, analyzed by quantitative methods, showed that the young group (operated upon at 4 weeks of age) developed more severe pulmonary hypertension with increased muscularization of arteries of all sizes and reduction in the size of those running with respiratory bronchioli and beyond. Since this response is similar to that seen in cases of left-to-right shunt associated with congenital heart defects and pulmonary hypertension early in life, it seems that the present experiments reproduce the early response of the growing lung to such hemodynamic disturbance.

Animals↗
PubMed1979

Bronchial mucosal cells.

The eight epithelial cell types and their features are described--the basal, Kultschitzsky, intermediate, brush, ciliated, serous, Clara, and mucous cell. In the irritated airway the separate secretory cell types are able to change, through transitional cell types, from the Clara and the serous to the mucous cell. Each type of epithelial cell may be associated with intraepithelial nerves, including sensory and motor, some adrenergic, some cholinergic. The epithelial surface is covered with a periciliary fluid layer in which the cilia beat. Turnover time of the epithelial cell population is faster in the young animal than old, in male than female, and in extrapulmonary than intrapulmonary airways. The epithelium responds differently to the first single exposure to tobacco smoke--in extrapulmonary airways a 'discharge' effect causes a fall in the apparent number of secretory cells while in intrapulmonary airways secretory cell number increases. Further exposures increase the secretory cell number to its maximum more rapidly in extrapulmonary than intrapulmonary airways. Differences between the response of the secretory cell population to isoproterenol and salbutamol indicate differences in the beta-adrenergic receptors in different airway regions.

Animals↗