Biomedical subjects
A S King
Publications and source records attributed to A S King.
An allometric study of pulmonary morphometric parameters in birds, with mammalian comparisons.
Comprehensive pulmonary morphometric data from 42 species of birds representing ten orders were compared with those of other vertebrates, especially mammals, relating the comparisons to the varying biological needs of these avian taxa. The total lung volume was strongly correlated with body mass. The volume density of the exchange tissue was lowest in the charadriiform and anseriform species and highest in the piciform, cuculiform and passeriform species. The surface area of the blood-gas (tissue) barrier, the volume of the pulmonary capillary blood and the total morphometric pulmonary diffusing capacity were all strongly correlated with body mass. The harmonic mean thickness of both the blood-gas (tissue) barrier and the plasma layer were weakly correlated with body mass. The mass-specific surface area of the blood-gas (tissue) barrier (surface area per gram body mass) and the surface density of the blood-gas (tissue) barrier (i.e. its surface area per unit volume of exchange tissue) were inversely correlated (though weakly) with body mass. The passeriform species exhibited outstanding pulmonary morphometric adaptations leading to a high specific total diffusing capacity per gram body mass, consistent with the comparatively small size and energetic mode of life which typify passeriform birds. The relatively inactive, ground-dwelling domestic fowl (Gallus gallus) had the lowest pulmonary diffusing capacity per gram body mass. The specific total lung volume is about 27% smaller in birds than in mammals but the specific surface area of the blood-gas (tissue) barrier is about 15% greater in birds. The ratio of the surface area of the tissue barrier to the volume of the exchange tissue was also much greater in the birds (170-305%). The harmonic mean thickness of the tissue barrier was 56-67% less in the birds, but that of the plasma layer was about 66% greater in the birds. The pulmonary capillary blood volume was also greater (22%) in the birds. Except for the thickness of the plasma layer, these morphometric parameters all favour the gas exchange capacity of birds. Consequently, the total specific mean morphometric pulmonary diffusing capacity for oxygen was estimated to be about 22% greater in birds than in mammals of similar body mass. This estimate was obtained by employing oxygen permeation constants for mammalian tissue, plasma and erythrocytes, as avian constants were not then available.(ABSTRACT TRUNCATED AT 400 WORDS)
Accidents claim 96,000 lives, but rate declining for some types.
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Not everyone agrees with new mammographic screening guidelines designed to end confusion.
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The lung of the emu, Dromaius novaehollandiae: a microscopic and morphometric study.
Qualitative and quantitative characteristics suggest that the lung of the emu is poorly adapted for gas exchange when compared with that of other birds. The granular epithelial cells extend over the air capillaries, and the squamous epithelial cells have microvilli indicating a poor differentiation of the epithelium of the exchange tissue. The surface area of the blood-gas tissue barrier per unit body mass was only 5.4 cm2/g, the volume of the pulmonary capillary blood per unit body mass was only 0.93 cm3/kg, and the tissue barrier was unusually thick (0.232 micron). These parameters produce a relatively small total morphometric pulmonary diffusing capacity for oxygen of 0.014 ml O2/sec/mbar/kg. The findings conform to the evolution of a very large flightless bird in a warm environment lacking effective predators.
A morphometric study of the lung of a Humboldt penguin (Sphenicus humboldti).
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Deficient anatomical capacity for oxygen uptake of the developing lung of the female domestic fowl when compared with the Red Jungle Fowl.
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The structure and innervation of the saccopleural membrane of the domestic fowl, Gallus gallus: an ultrastructural and immunohistochemical study.
Microscopic studies have shown the saccopleural membrane in the respiratory system of the domestic fowl to consist of a sheet of three dense layers of collagen fibres covered dorsally and ventrally by mainly simple squamous epithelium. On the ventral surface, which faces into the caudal thoracic air sac, there are occasional ridges of pseudostratified ciliated epithelium. Many nerve bundles are present throughout the membrane, the larger bundles of myelinated and unmyelinated axons being confined to the lamina propria under the dorsal epithelium (parietal pleura). In addition to axonal profiles with the ultrastructural appearance of cholinergic or adrenergic axons, peptidergic-type axons were identified. Immunofluorescence studies demonstrated VIP-, substance P-, somatostatin- and enkephalin-immunoreactive fibres in the membrane. Although it has been suggested that receptors may be present in this region of the respiratory system, none of the axons have features suggestive of sensory terminals, although many axonal profiles are closely associated with the epithelia where no obvious effector cells are present.
The abdominal air sac ostium of the domestic fowl: a sphincter regulated by neuro-epithelial cells?
A microscopic study of the ostium of the abdominal air sac of the domestic fowl has shown that the ostium has a sphincter-like ring of well innervated smooth muscle. Three types of neuro-epithelial cell characterised by their content of numerous large granular vesicles are found in the wall of the ostium. Type I cells are present within the submucosal nerve plexus and appear to be morphologically similar to SIF cells. Type II cells occur in the lamina propria, in clusters or cords, are often associated with fenestrated capillaries, and have synaptic contact with axonal terminals containing small agranular vesicles. The cells of Types I and II are not intra-epithelial and therefore differ from the cells which have been found elsewhere in the respiratory tract of the domestic fowl and other vertebrates. Type III cells are intra-epithelial, and some of those in the basal region of the epithelium are associated with axon terminals. Type III cells are similar in ultrastructure and location to neuro-epithelial cells found elsewhere in the major airways of the domestic fowl. They also resemble cells in neuro-epithelial bodies in amphibian, reptilian and mammalian lungs, although neuro-epithelial bodies have not been found in the lung of this species of bird. The morphology of the ostium suggests that it may have a sphincter-like function, possibly regulated by the neuro-epithelial cells. The presence of a mucociliary epithelium and defensive tissue in the lamina propria indicates that the ostium is the site of defence mechanisms.
Aortico-pulmonary bodies in the domestic fowl: ultrastructure, innervation and secretion.
In adult and immature domestic fowl, aggregations of large pale-staining cells were found in the wall of the aorta, and of the pulmonary trunk and arteries, in modified regions typified by interruption or loss of elastic laminae and smooth muscle cells. Encapsulated extramural aggregations of similar cells were identified either on the actual surface or well outside the arterial wall of the aorta, and pulmonary trunk and arteries. The electron microscope revealed that the pale cells in these intramural and extramural structures were granular cells characterised by dense-cored vesicles typically about 60-140 nm in diameter. Supporting cells partly invested the granular cells. These intramural and extramural structures are interpreted as aortico-pulmonary bodies. The extramural and to a lesser extent the intramural cells were associated with many axonal endings and fenestrated blood capillaries. The axonal endings formed presumptive afferent, efferent and reciprocal synapses with the granular cells. Both intra- and extramural granular cells displayed evidence of exocytosis and were also shown by autoradiography to handle amines. It is concluded that the ultrastructural features of these aortico-pulmonary bodies resemble those of the carotid body. It is therefore suggested that the aortico-pulmonary bodies of the domestic fowl have a chemoreceptor function similar to that of the carotid body. It is also suggested that they may have a general secretory function.
The afferent and efferent myelinated fibres of the avian cervical vagus.
The numbers and diamters of the myelinated fibres in the cervical vagus have been studied in normal birds and after midcervical and intracranial vagotomy. The mean total number of myelinated fibres was about 9066 in the right cervical vagus and 8535 in the left. In the right nerve about 4223 of these fibres were afferent and 4843 were efferent; of the afferent fibres about 520 had their cell bodies in the proximal vagal ganglion (or distal glossopharyngeal ganglion) and 3703 in the distal vagal ganglion. In the left cervical vagus, about 4132 afferent fibres had their cell bodies in the distal ganglion, and there were probably about 3883 efferent fibres. The largest fibres in the cervical vagus were usually about 7 micrometer in diameter, fibres of 3 micrometer or less comprising from 72% to 89% of the total.
Afferent and efferent myelinated fibres in branches of the avian vagus.
The numbers of afferent and efferent myelinated fibres in the branches of the vagus nerve in the domestic fowl were studied. The vago-glossopharyngeal anastomosis contained large fibres (up to 14 micrometer), the majority of which were efferent. The right recurrent nerve contained more fibres than the left one; in the right recurrent nerve about one third of the myelinated fibres were afferent. Almost all the myelinated fibres in the right cranial cardiac nerve were afferent. About half of those in the pulmono-oesophageal nerve and in the thoracic vagus were afferent.
The topographical anatomy and blood supply of the carotid body region of the domestic fowl.
The topographical anatomy of the carotid body region was investigated on both sides in 30 adult domestic fowls (Gallus gallus domesticus). On each side of the body the two parathyroid glands always adhered to each other, the caudal gland being the smaller. The right cranial parathyroid usually touched the thyroid gland, but on the left side the two glands were nearly always separate. The ultimobranchial gland was usually attached to the parathyroid glands on the left side, but was always well separated on the right side. The carotid body, the identity of which was checked by light and electron microscopy, was ovoid in shape, whitish in colour, and about 0.8 x 0.6 x 0.5 mm in size. It was almost always in direct contact with the medial surface of one or both parathyroid glands have commonly been portrayed astopographically separate from each other. The oesophagotracheobronchial artery, the artery to the carotid body, and the caudal thyroid artery arose close together, though in variable positions, from the lateral aspect of the common carotid artery. The artery to the carotid body was always the middle of the three. The venous drainage of the carotid body was associated with the veins of the parathyroid and ultimobranchial glands. The carotid body was innervated by a filament from the distal vagal ganglion. The topographical observations on the carotid body region have been compared with those of other authors. The cranial and caudal parathyroid glands have commonly been portrayed as topographically separate from each other. The carotid body has seldom been depicted in direct contact with the parathyroid glands. The size of the carotid body has invariably been shown far too large. These discrepancies are discussed and are attributed largely to the reliance by other authors on serial reconstruction rather than microdissection.
The avian bronchial arteries: species variations.
The bronchial arteries arose from the oesophagotracheobronchial branches of the common carotid arteries. In the goose, duck, Muscovy duck, and turkey several small bronchial arteries supplied the whole length of each primary bronchus, including the orifices of the secondary bronchi. In the guinea-fowl and quail similar bronchial arteries supplied only the extrapulmonary part of the primary bronchus. In the pigeon a single true bronchial artery supplied the extrapulmonary part of each primary bronchus; this pair of bronchial arteries arose asymmetrically from a common bronchial trunk derived from the left oesophagotracheobronchial artery only. In this species, and in the guinea-fowl and quail, the intrapulmonary part of the primary bronchus was supplied by the pulmonary artery. There were no branches to the exchange tissue in any species. In all species the bronchial veins of the extra-pulmonary part of the primary bronchus drained via oesophageal veins, whereas those of the intrapulmonary part emptied into branches of the pulmonary vein.
Pulmonary arteriovenous anastomoses in the avian lung: do they exist?
A search for pulmonary arteriovenous anastomoses was made in 15 adult domestic fowls using Lycopodium spores and microspheres. The diameter of the spores and microspheres ranged from about 10 to 33 mum. To dilate any pulmonary arteriovenous anastomoses, the birds were warmed to induce panting, killed with chloroform, or injected intravenously with papavarine. The spores or microspheres were injected either into the jugular vein under anaesthesia, or into the pulmonary artery after death. After the pulmonary arterial injections, the effluent from the pulmonary vein, and histological sections of the lungs, were examined for spores or microspheres. When injections were made into the jugular vein, blood smears from the pulmonary veins, left atrium, and the aorta, as well as histological sections of the lungs and other organs were inspected. The results of all these experiments showed that no spores or microspheres were ever found on the venous side of the pulmonary circulation, indicating absence of pulmonary arteriovenous anastomoses.
The functional anatomy of the bronchial circulation of the domestic fowl.
The bronchial circulation was studied in 25 adult domestic fowls. The right and left bronchial arteries originated caudal to the syrinx from a bronchoesophageal artery which is a branch of the right common carotid artery. Each bronchial artery ramified on the wall of the extrapulmonary part of the corresponding primary bronchus and finally anastomosed directly with a branch of the pulmonary artery at the hilus of the lung. Thr bronchial artery did not accompany the intrapulmonary part of the primary bronchus. The branches of each bronchial artery formed an anastomosing network on the wall of the extrapulmonary part of the primary bronchus. The calibre of the bronchial artery at its anastomosis with the branch of the pulmonary artery was greater than at its origin from the bronchoesophageal artery. Intravenous injections of Lycopodium spores indicated that the blood flows from the pulmonary artery into the bronchial artery. Small bronchial veins drained the extrapulmonary part of the primary bronchus into the pulmonary vein and the oesophageal veins. The intrapulmonary part of the primary bronchus was supplied by branches of the pulmonary artery and drained by tributaries of the pulmonary vein. The blood supply to the primary bronchus could constitute a shunt capable of passing blood from the pulmonary artery into the pulmonary vein without going through the exchange tissue. The parabronchial (atrial) muscles received a blood supply directly from the exchange tissue via septal venules which formed a network underneath the muscle bundles, without actually penetrating between the muscle cells. These venules drained into atrial veins which were tributaries of the pulmonary vein. The atrial muscles probably also received oxygen by direct diffusion from the parabronchial lumen. The pleura was supplied by the oesophageal branches of the bronchoesophageal artery, and by small twigs from the internal thoracic and intercostal arteries.
Nephrosis and papillary necrosis after pyelonephritis.
We present a case of nephrotic syndrome complicating acute pyelonephritis in a 45-year-old man. His first attack of acute bacterial pyelonephritis had two unusual features: transient nephrotic syndrome and chronic recurrent episodes of papillary necrosis. The former, which lasted for two weeks, was characterized by edema, excretion of 7.7 g of urinary protein per 24 hours and hypoproteinemia (1.8 g per 100 ml). A percutaneous renal biopsy two weeks after the height of the nephrotic state showed normal glomeruli by light and electron microscopy and immunohistologic studies. Interstitial changes were noted. Over two years the patient has passed approximately 50 fragments, characterized as necrotic tissue containing tubular structures. He has no evidence of diabetes mellitus, urinary-tract obstruction or ureteral reflux, analgesic abuse or atypical vasculitis. He is afebrile but has recurrent bacteriuria despite antibiotics. This case demonstrates that acute pyelonephritis must be added to the list of diseases causing the nephrotic state.