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Biomedical subjects

D Heath

Publications and source records attributed to D Heath.

246 records · Page 14Linked to original sources
PubMedDate not supplied

[Pulmonary arterial hypertension and systemic lupus erythematosus. Apropos of 2 cases. Review of the literature].

Pulmonary arterial hypertension may develop in patients with systemic lupus erythematosus (SLE) in the absence of lung tissue lesion or embolism in the pulmonary circulation. Its mechanisms and prognosis are imperfectly known, although various suggestions have been made concerning the possible role of pulmonary arterial spasm, immune complex arteritis or arterial wall fibrosis. We report two cases of SLE in female patients who presented with clinical signs of pulmonary arterial hypertension. The fact that pulmonary arterial hypertension regressed completely in one patient and resulted in death in the other points to different pathogenic mechanisms. In the first patient the dramatic therapeutic effectiveness of a calcium inhibitor suggests that an arterial spasm was involved, whereas the anatomical lesions found in the second patient are in favour of a fibrotic inflammatory arteritis. This pathogenic heterogeneity of pulmonary arterial hypertension in SLE, which may correspond to different evolutive stages of the disease, is documented by a review of the literature with special attention to the frequency and to the clinical biochemical, haemodynamic and histological aspects of this complication of SLE.

Adult↗
PubMedDate not supplied

Three-dimensional helical CT of intrahepatic venous structures: comparison of three rendering techniques.

OBJECTIVE: To define the advantages and disadvantages of various rendering techniques to obtain three-dimensional (3D) displays of intrahepatic venous structures with helical CT data. MATERIALS AND METHODS: After rapid preprocessing segmentation of the liver, helical CT data (8 mm slice thickness overlapped every 4 mm) from 10 patients were reconstructed using maximum intensity projection (MIP), volume rendering, and surface rendering algorithms. Three-dimensional imaging was evaluated blindly and independently by three observers for presence of artifacts and overall quality. RESULTS: Three-dimensional displays showed the hepatic veins and fifth order portal branches with the volume and MIP rendering techniques. Best overall quality in the 3D representation of the liver was achieved with the MIP technique (p < 0.05). Small details in venous anatomy and portal involvement by tumor were better imaged with the MIP technique. "Stair-step" artifacts markedly degraded the 3D displays obtained with the surface rendering technique, making it inappropriate for imaging the intrahepatic venous structures. CONCLUSION: Maximum intensity projection appears to be an adequate technique to perform 3D imaging of intrahepatic venous structures with helical CT data when 8 mm slice thicknesses overlapping every 4 mm are used. However, optimization of imaging protocols needs to be done and compared in a larger series.

Aged↗
PubMedDate not supplied

Glomic cells and their peptides in the carotid body of the human fetus.

Carotid bodies from 15 human fetuses of gestational ages 13-19 weeks were examined by light and electron microscopy. They were also labeled with antisera to methionine- and leucine-enkephalins, substance P, and bombesin. At 13 weeks of gestation most fetal glomic cells formed a homogeneous population but a few could be distinguished by light microscopy as rounded, pale fetal chief cells or elongated, darker fetal sustentacular cells, a distinction that became more certain with increasing gestational age. Electron microscopy confirmed this distinction, in which fetal chief cells contained dense-core vesicles and were partially enfolded by cytoplasmic extensions of fetal sustentacular cells. Immunoreactivity to methionine- and leucine-enkephalins was found at all gestational ages and was confined largely to fetal chief cells. Immunoreactivity to substance P was less specific, and there was no reaction for bombesin. Thus, by as early as the 13th week of gestation the two principal types of cell of the mature human carotid body begin to become recognizable on paraffin-embedded sections stained with hematoxylin and eosin. Furthermore, fetal chief cells can synthesize the peptides found in the adult.

Carotid Body↗
PubMedDate not supplied

The lung at high altitude.

Men and mammals (excluding the indigenous mountain species) who are born at high altitude, or who ascend to live there for a long period, have to undergo acclimatization which affects virtually every system in the body. Since chronic hypoxia is the most important adverse factor in the mountain environment, the lung plays a major part in the process and shows many alterations in structure and function. However, we remain ignorant about many aspects of acclimatization of the lung to hypoxia especially at the ultrastructural level with respect to those cells whose normal function is not yet established. An account of what is known is given in this paper.

Acclimatization↗
PubMedDate not supplied

Pulmonary capillary haemangiomatosis.

A Cypriot male of 22 years died after suffering recurrent daily haemoptyses of varying severity and slowly increasing effort intolerance for a period of four and a half years. Examination of a lung biopsy specimen revealed dilated vascular channels suggestive of a congenital anomaly of the pulmonary vasculature. Histological examination of the lung following necropsy revealed the diagnosis of pulmonary capillary haemangiomatosis. In this condition sheets of thin-walled blood vessels infiltrate the lung parenchyma, the walls of pulmonary arteries and veins, the bronchi and the pleura. The infiltration of pulmonary veins and venules induces secondary pulmonary veno-occlusive disease. This appears to be the second example of this disease which has been reported. It is open to clinical and histological mis-diagnosis and clinicians and pathologists should be aware of the existence of this entity.

Adult↗
PubMedDate not supplied

A financial planning model for estimating hospital debt capacity.

A computer-based financial planning model was formulated to measure the impact of a major capital improvement project on the fiscal health of Stanford University Hospital. The model had to be responsive to many variables and easy to use, so as to allow for the testing of numerous alternatives. Special efforts were made to identify the key variables that needed to be presented in the model and to include all known links between capital investment, debt, and hospital operating expenses. Growth in the number of patient days of care was singled out as a major source of uncertainty that would have profound effects on the hospital's finances. Therefore this variable was subjected to special scrutiny in terms of efforts to gauge expected demographic trends and market forces. In addition, alternative base runs of the model were made under three distinct patient-demand assumptions. Use of the model enabled planners at the Stanford University Hospital (a) to determine that a proposed modernization plan was financially feasible under a reasonable (that is, not unduly optimistic) set of assumptions and (b) to examine the major sources of risk. Other than patient demand, these sources were found to be gross revenues per patient, operating costs, and future limitations on government reimbursement programs. When the likely financial consequences of these risks were estimated, both separately and in combination, it was determined that even if two or more assumptions took a somewhat more negative turn than was expected, the hospital would be able to offset adverse consequences by a relatively minor reduction in operating costs.

California↗
PubMedDate not supplied

The influence of hypoxia on the population density of alveolar macrophages in the lungs of rats.

The population density of alveolar macrophages was measured in the lungs of hypoxic rats, in rats which had recovered from a period of hypoxia, and in untreated controls. Alveolar macrophages were most numerous in hypoxic animals. The recovery group contained fewer macrophages than the hypoxic group but more than the controls. In the hypoxic animals the distribution of alveolar macrophages was not homogeneous either within an individual rat or amongst the group as a whole. This suggests that the increase in their number may be stimulated by the secondary effects of hypoxia rather than by its direct interference with their metabolism.

Animals↗