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Biomedical subjects

D Heath

Publications and source records attributed to D Heath.

At least 91 records · Page 5Linked to original sources

Plexiform lesion in bronchopulmonary anastomosis.

A cellular lesion developed in the bronchial component of a bronchopulmonary anastomosis in a girl of 6 years with primary pulmonary hypertension. Its histological features were consistent with those of a plexiform lesion.

Arterio-Arterial Fistula↗

Pulmonary endocrine cells in various species in the Himalaya.

The numbers, morphology and distribution of pulmonary endocrine cells in goats, sheep and the yak and its interbreeds with cattle, dzos and stols, were studied after their demonstration by means of the peroxidase-antiperoxidase technique with a polyclonal antiserum raised in the rabbit to human neuron-specific enolase, a marker for neuroendocrine cells. The numbers, morphology and distribution were related to species and not to residence at high altitude. Pulmonary endocrine cells were common and mainly distributed as solitary cells in the epithelium of the bronchial tree in sheep. They were much less common and found mainly as clusters in the alveolar capillary walls in goats and in the yak and its interbreeds with cattle.

Altitude↗

Ultrastructure of early plexogenic pulmonary arteriopathy.

A lung biopsy specimen from a young woman with the clinical features of primary pulmonary hypertension showed grade 2 plexogenic pulmonary arteriopathy. Electron microscopy revealed 'dark', electron-dense smooth muscle cells in the inner part of the media of muscular pulmonary arteries. Many of these transformed myocytes had migrated into the lumens of pulmonary arteries and arterioles which they occluded. This migration of smooth muscle cells was associated with a substantial increase in the number of pulmonary endocrine cells in the bronchioles containing bombesin and calcitonin.

Adult↗

Anatomical variations in human carotid bodies.

The variations in anatomical structure and position of both carotid bodies were noted in 100 consecutive subjects who came to necropsy. Considerable variations in form were found. Although most carotid bodies (83% on the right and 86% on the left) were of the classic ovoid type, an appreciable minority was bilobed (9% on the right and 7% on the left) or double (7% on the right and 6% on the left); 1% were leaf shaped. All these anatomical variants have to be distinguished from the pathologically enlarged carotid body that may have a smooth or finely nodular surface. Anatomical variants (such as the bilobed) may themselves enlarge as a consequence of carotid body hyperplasia.

Aged↗

A pathophysiological study of 10 cases of hypoxic cor pulmonale.

A pathophysiological study of the pulmonary vasculature in 10 patients with hypoxic cor pulmonale and severe airways obstruction (five treated and five untreated with long-term oxygen) is presented. The media of muscular pulmonary arteries was normal or atrophic but, in the intima, there was active deposition of longitudinal muscle, fibrosis and elastosis. In the arterioles a medical coat of circular smooth muscle bounded by a new internal elastic lamina had developed, while there was deposition of longitudinal muscle and fibrosis in the intima. In five cases the lumen was subdivided into parallel tubes, found by serial section to lead into alveolar capillaries. These features are distinctive of hypoxaemia and obstructive airways disease. Changes continued until death. The conspicuous longitudinal muscle may be attributable to stretching of vessels round distorted terminal airways; further exploration into mechanisms is required. The hypothesis that vascular changes follow hypoxic vasoconstriction is no longer tenable. No correlations were found between quantitative pathological findings and arterial blood gas tensions, pulmonary artery pressure or haematocrit. There were no differences between patients treated or not treated with oxygen which might suggest that it arrests pathological changes. Thus, once a patient is given oxygen, survival probably depends as much on progressive mechanical changes in the lung as on continuing hypoxaemia.

Airway Obstruction↗

Immunoreactivity to various peptides in the human carotid body.

Human carotid bodies, removed at routine necropsies, have been subjected to radioimmunoassay for various peptides. Average levels of immunoreactivity, expressed in pm/g, were: met-enkephalin 612, leu-enkephalin 162, bombesin 73, neurotensin 67, VIP 9 and substance P 16. No alpha-hANP immunoreactivity could be detected.

Carotid Body↗

Multicentre clinical trial of low volume fresh frozen plasma therapy in acute pancreatitis.

Fresh frozen plasma (FFP) has been proposed as a specific therapy for acute pancreatitis. Reduced mortality encountered in an uncontrolled clinical study and a controlled experimental study may be attributable to replenishment by FFP of the naturally occurring antiprotease system. To investigate this potential therapy further, 202 patients presenting with acute pancreatitis were randomized to receive FFP (2 units daily for 3 days) or a similar volume of colloid control as part of their intravenous fluid therapy. Clinical progress was monitored and the major serum antiproteases (alpha 1-antiprotease and alpha 2-macroglobulin) were measured on days 1, 3 and 7. There was no significant difference between the two groups in terms of clinical outcome. alpha 1-Antiprotease levels rose significantly from day 1 to day 3 in both groups (P less than 0.0001) and remained elevated at day 7. alpha 1-Antiprotease is an acute phase protein in man and raised serum levels would be anticipated. FFP appears to have no effect on the magnitude of this rise. Serum alpha 2-macroglobulin levels were reduced in both groups on day 1 and continued to fall significantly from day 1 to day 3 in the colloid control group (P less than 0.005) whilst remaining substantially unaltered in patients receiving FFP (P = 0.6527). alpha 2-Macroglobulin plays a central role in the elimination of proteases during acute pancreatitis and the ability of relatively low volumes of FFP to reduce the fall in serum alpha 2-macroglobulin levels seen during the early stages of this disease may have therapeutic implications.

Acute Disease↗

Relation between histological age-changes in the carotid body and atherosclerosis in the carotid arteries.

Histological changes in the human carotid body associated with increasing age are accompanied by occlusive atherosclerotic lesions in the arteries of the carotid bifurcation, and are probably ischaemic in origin. The carotid sinus, however, is unusually susceptible to the development of atheroma and its occlusion appears to have little influence in compromising blood flow through the glomic arteries.

Adult↗

The pathology of the early and late stages of primary pulmonary hypertension.

During the course of a case of primary pulmonary hypertension occurring in a 24 year old man lung tissue became available at heart-lung transplantation in 1986 and from a lung biopsy carried out in 1981. In 1986 the sections showed classic plexogenic pulmonary arteriopathy. In 1981 they revealed migration of myofibroblasts into the intima and lumen of pulmonary arteries and arterioles, the identification of the cells being confirmed by electron microscopy. During the five years that the pulmonary vascular pathology progressed to the formation of plexiform lesions there was an increase in the number of bronchiolar endocrine cells that were immunoreactive to bombesin and calcitonin. This study demonstrates that the classic pathogenesis of primary plexogenic pulmonary arteriopathy originates years earlier as a migration of cells of muscular pedigree from the media into the intima of the pulmonary arteries and arterioles.

Adult↗

Mast cells in the human carotid body.

Mast cell counts were carried out on sections of human carotid bodies from 39 subjects showing one of four stages of histological change associated with aging, and in five subjects showing different forms of histopathology in the carotid body associated with disease. There was no relation between mast cell density and age or the histological changes associated with aging of glomic tissue. The normal range of mast cell density calculated in terms of the 80% confidence limits was 18.5 to 67.5/mm2. In three middle aged subjects with carotid bodies of normal histological appearance there was an abnormally high density of 83 to 96/mm2. In two elderly subjects showing age changes of fibrosis and accumulation of lymphocytes there was an abnormally low density of 12/mm2 or less. Mast cell density was not related to different types of carotid body hyperplasia. The mast cells were essentially stromal in location, usually closely applied to the walls of small glomic blood vessels, and were rarely found in intimate association with glomic chief cells. This suggests that mast cells are not directly concerned with the functions of glomic cells but does not preclude the possibility that they may have some effect on regulating glomic blood vessels and thus participate in the distribution of blood supply within the carotid body.

Adolescent↗

Effects of glucocorticoids on the rabbit carotid body.

Weekly intramuscular injections of slow-release, depot methyl prednisolone to 15 adult Dutch rabbits did not bring about an increase in the volume of their carotid bodies. However, they caused swelling of chief cells with discrete areas of pallor in the cytoplasm. Factors responsible for these changes appear to be increased storage of catecholamines and an increased number of swollen mitochondria.

Adrenal Glands↗

Effects on the rabbit carotid body of stimulation by almitrine, natural high altitude, and experimental normobaric hypoxia.

Rabbits were given intraperitoneal injections of almitrine in ascending doses for 5 weeks. They were compared with a control group and with a group of rabbits which had been exposed from birth to the natural hypobaric hypoxia found at Cerro de Pasco (433 m) in the Peruvian Andes. A further group of animals was placed in an experimental normobaric chamber for either 3 or 6 months to subject them to the same degree of hypoxia as that occurring in Cerro. The carotid bodies of the rabbits in all these groups were processed for light and electron microscopy, and examined both qualitatively and quantitatively. The carotid bodies in the group given almitrine showed no changes in their size or in the population of their glomic cells when compared with controls. In contrast, the carotid bodies of Peruvian rabbits were greatly enlarged with a disproportionate increase in the population of the light variant of chief cell. Rabbits from the hypoxic chamber also had enlarged carotid bodies but those killed after 3 months showed an increase in the dark variant of chief cell, whereas after 6 months this cell was reduced in number. There was also intense cytoplasmic vacuolation. Election microscopy confirmed these changes and revealed that dark cells had larger, more pleomorphic granules than the light variant. Vacuolation of the granules in light cells was most pronounced in Peruvian rabbits, but was uncommon in animals exposed to hypoxia for 3 months. We suggest that the dark cell responds to the early stages of hypoxia but later matures into the light variant of chief cell.

Almitrine↗

The thickness of the alveolar capillary wall in the human lung at high and low altitude.

An ultrastructural study of lung biopsy specimens from an adult mestizo highlander from La Paz (3800 m) and three lowlanders from London showed no significant difference in the thickness of the alveolar capillary wall, the thickness in the highlander being 0.65 micron and the range in the lowlanders being 0.57-0.69 micron. The thickness of the blood-air barrier in a mestizo girl of 4 years born and living in La Paz was 0.47 micron. These findings suggest that the alveolar capillary wall in the acclimatized highlander does not differ in thickness from the lowlander. This contrasts with our previous findings in native high altitude guinea pigs which indicate that the alveolar capillary wall is thinner in such indigenous mountain species which are adapted genetically rather than acclimatized to hypobaric hypoxia.

Adult↗

The carotid bodies in coarctation of the aorta.

The carotid bodies were found to be enlarged at the necropsy of a 61-year-old man with congenital coarctation of the aorta. The enlargement was found to be due to hyperplasia of the sustentacular (type II) cells and considered to be a response to systemic hypertension. The proliferation of these cells had compressed the small remaining cores of chief (type I) cells which contain catecholamines and peptides. This case is illustrative of the fact that the carotid bodies may enlarge in some forms of congenital heart disease. The histological changes in the glomic tissue in any one type of congenital cardiac anomaly appear to be related to the nature of the underlying physiological disturbance. Thus the raised intravascular pressure in the upper part of the body in coarctation of the aorta appears to lead to hyperplasia of sustentacular cells.

Adult↗