Endothelin (ET), recently isolated from culture supernatant of porcine aortic endothelial cells, is a novel potent vasoconstrictive substance. In this paper a highly specific rabbit antisera against endothelin was used to study the localization of ET in the isolated endothelial cells, from human umbilical veins and porcine arota, and that of ET in the cryostat cross sections of porcine aorta by using ABC immunohistochemical technique. The results demonstrate that a varied amounts of specific ET-like immunoreactive substance exist in the endothelial cytoplasm of human umbilical veins and porcine aorta which provides the mor- phological evidence for elucidating the endocrine function of vascular endothelial cells.

Brain natriuretic peptide(BNP) is a recently discovered novel neuropeptide of 26 amino acid residues, isolated from porcine brain, that is of similar potency to atrial natriuretic factor(ANF) in natriuretic, diuretic, hypotensive and smooth muscle relaxant activities. we used a highly selective antisera against BNP raised in rabbit to observe its distribution and localization in some brain areas and some other peripheral tissues by utili zing high sensitive avidin-biotin-peroxidase complex technique. Positive brain natriuretic peptide immunoreactive (BNPir) fibers and cell bodies were observed in the lateral hypothalamic area, caudate-putamen, hippocampus, amygdala, and supraoptic and paraventricular nuclei. A lot of BNPir granules were also found in rat atria. They were of similar localization to that of ANF. Most of the specific granules were accumulated in cytoplasm at both nuclear poles of atrial myocytes. The BNP immunoreactivity is less intense than that of the ANF. Some of scanty, diffuse and fine BNPir granules could also be observed in ventricular myocytes.The coexistence of both BNP and ANF in the brain and heart indicates that BNP may function as a neuropeptide and circulating hormone, and suggests the possibility that the physiological effects such as diuretic natriuretic, hypotensive and smooth muscle relaxant activities so far thought to be mediated by ANF may be regulated through a dual mechanism involving both BNP and ANF. In addition, some BNPir positive cells were also present in the anterior and intermediate lobes of rat pituitary gland. The significance of BNP in hypophysis would be elucidated in the further studies.

Background Coal workers' pneumoconiosis is a serious occupational disease in China. Exhaled volatile organic compounds (VOCs) can serve as the "breath fingerprint" of internal pathological processes, which provides a theoretical basis for exhaled VOCs to be used as potential non-invasive biomarkers for early diagnosis of coal workers' pneumoconiosis. Objective To screen out the characteristic VOCs and important characteristic VOCs of exhaled air in patients with coal workers' pneumoconiosis, and to explore the potential of these VOCs as biomarkers for early non-invasive diagnosis of the disease. Methods In this study, 27 VOCs in the exhaled breath of 22 patients with stage I coal workers' pneumoconiosis, 77 workers exposed to dust, and 92 healthy controls were quantitatively detected by thermal desorption gas chromatography-mass spectrometry (TD-GC-MS). Substances with P<0.05 in univariate analysis and variable importance projection (VIP) >1 in supervised orthogonal partial least squares discriminant analysis (OPLS-DA) model were selected as the characteristic VOCs for early diagnosis of coal workers' pneumoconiosis. Age was included in the LASSO regression model as a covariate to screen out important characteristic VOCs, and the diagnostic performance was evaluated by receiver operating characteristic (ROC) curve. Spearman correlation was further used to explore the correlation between important characteristic VOCs and clinical lung function indicators. Results Through univariate analysis and OPLS-DA modeling, 8 VOCs were selected, including 2-methylpentane, 3-methylpentane, n-hexane, methylcyclopentane, n-heptane, methylcyclohexane, 4-methyl-2-pentanone, and 2-hexanone, in exhaled breath of patients with coal workers' pneumoconiosis. The concentrations of 4 VOCs, including 3-methylpentane, n-hexane, 4-methyl-2-pentanone, and 2-hexanone, showed a decreasing trend with the increase of dust exposure years. By LASSO regression, the important characteristic VOCs of the coal workers' pneumoconiosis group and the dust exposure group were n-hexane, methylcyclohexane and 4-methyl-2-pentanone, and the important characteristic VOCs of the coal workers' pneumoconiosis group and the healthy group were 2-methyl-pentane and 4-methyl-2-pentanone. The ROC analysis showed that the area under the curve (AUC) of n-hexane, methylcyclohexane, and 4-methyl-2-pentanone were 0.969, 0.909, and 0.956, respectively, and the AUC of combined diagnosis was 0.988 and its Youden index was 0.961, suggesting that these results can serve as a valuable reference for further research on early diagnosis. The Correlation analysis found that there was a positive correlation between n-hexane and lung function indicators in the important characteristic VOCs, indicating that it could indirectly reflect the obstruction of lung function ventilation, further proving that important characteristic VOCs have the potential to monitor lung function decline. Conclusion Three important characteristic VOCs selected in this study have the potential to be used as non-invasive biomarkers for early diagnosis and disease monitoring of coal workers' pneumoconiosis, and are worthy of further study and verification.