[Reflexes from vascular receptors of the rabbit ear under the influence of sodium nitrate and platyphyllin and modes of their mechanism].
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The diversity of tissue and cell organization in the leaves of dicots is explained as the mutual effect of light and water fluxes distribution. Equally with certain data about the role of light distribution, the same influence of water flux distribution on the leaf structure is recognized. Dorsiventral leaves of woody plants have an adequate to structure dorsiventral ring of water circulation. Rising flux from the xylem allocates via leaf apoplast with intermediate accumulation in upper epiderma. Descending flux starts and returns to bundle moving from cell to cell along the symplast (ER) of spongy parenchyma, bundle sheath and terminal complexes of the phloem. Isolateral leaves of herbs have a concentric pathway of solute circulation corresponding to the structure. Xylem flux allocates via symplast with water and nitrogen accumulation in paraveinal parenchyma. Water returns to phloem by transit via the apoplast in parallels with phloem exudate formation. Structural features correlated with the model of water circulation in the leaf are described. Numerous lines of leaf evolution well-known for dicots collect to two main topics which are typical for woody and herbaceous forms of dicots. The mechanisms of cell and tissue differentiation under the control of transport fluxes are discussed with special attention to ontogenetic and phylogenetic trends.
Vascular corrosion casting was used to search for angiogenesis in the blood vessels of the lungs of rats given monocrotaline. Animals treated with monocrotaline had new well-differentiated arteries and veins on their pleural surfaces. Animals not treated had no large vessel on their pleural surfaces. Animals receiving monocrotaline had capillaries around major arteries that were more dense, widened, and less tubular than normal. These capillaries occasionally occurred in sheets and had blind endings. The control animals had delicate, uniform, tubular capillaries. Alveolar capillaries in both groups showed no evidence of increase in size or number or change in shape. Light microscopy confirmed the finding of new vessels found with the casts. The finding of angiogenesis on the pleural surface and in the bronchovascular bundle, but not in the alveolar capillaries, suggests a basic difference in how these capillary beds respond to angiogenic stimuli. If alveolar capillaries are unable to undergo angiogenesis, concepts of lung development and tumor growth may be significantly altered. The lung may be a unique organ to study angiogenesis because of the different angiogenic potential of its two circulations. Study of these differences may lead to better understanding of inhibition of angiogenesis.
The adverse drug reaction (ADR) of traditional Chinese medicine (TCM) has been concerned nowadays. Some bans were published to limit their use abroad. There wasn't a feasible criterion to reply to the ADR of TCM yet in China. The ADR of 6 kinds of typical TCM which state attached importance to was chosen to discuss. Based on the retrospect investigation, the objectivity of ADR was explored in this study.
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Of 41 equids referred to a veterinary teaching hospital in the Pacific northwest because of dyspnea and inspiratory noise, 3 ponies were diagnosed as having liver failure, most likely attributable to pyrrolizidine alkaloid toxicosis. Dyspnea appeared to be caused by laryngeal and/or pharyngeal paralysis. It is proposed that this paralysis was a manifestation of hepatic encephalopathy. Although these clinical signs are not common for pyrrolizidine toxicosis, practitioners should be aware of the possibility so that misdiagnosis of other causes of inspiratory dyspnea may not be made.
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Hypertension is one of the most important risk factors for atherosclerosis, yet no morphologic evidence exists to explain it. This study is an attempt to identify lesions in the main pulmonary artery of rats in which pulmonary hypertension was induced by a single dose of monocrotaline. Pulmonary artery pressure was measured directly by catheterization or indirectly by measuring right ventricular thickness. Lesions were studied by both light and electron microscopy. As in previous studies in which monocrotaline was given chronically, we found thickening of the main pulmonary artery. We also found widening of subendothelial space, change in smooth-muscle cell polarity, shape, and organelle content (indicating change from contractile to secretory), focal areas of muscle necrosis and elastolysis. Interestingly, cardiac muscle was observed in adventitia of both controls and treated animals.
Changes in elastin and collagen synthesis in the pulmonary artery wall, assessed both biochemically and ultrastructurally, were related to the development of progressive pulmonary hypertension induced by the toxin monocrotaline. Male Sprague-Dawley rats (200 to 225 gm) were injected subcutaneously in the hind flank with either monocrotaline (60 mg/kg) or an equivalent volume of saline and studied 8, 16 and 28 days later. At each time point, the right ventricle and left ventricle with septum were separated and weighed to follow the development of right ventricular hypertrophy. The hilar pulmonary artery was assessed by light microscopy for medial hypertrophy and by electron microscopy for changes in the endothelium, subendothelium and media. The mainstem pulmonary artery was used to determine synthesis of elastin and collagen by in vitro incorporation of [14C]proline into nonelastin, [14C]hydroxyproline into collagen, and [3H]valine into cyanogen bromide-insoluble elastin. In addition, total content of insoluble elastin was determined by weight of the residue after cyanogen bromide digestion and of collagen by total hydroxyproline content in sodium dodecyl sulfate and cyanogen bromide extracts. Eight days after monocrotaline injection, there was pulmonary artery endothelial swelling and a significant decrease in the number of myoendothelial junctions (p less than 0.05) associated with a decreased proportion of amorphous elastin in the media (p less than 0.01). Sixteen days after monocrotaline injection, a decrease in the proportion of elastin in the media was still evident (p less than 0.01) despite an apparent increase in insoluble elastin synthesis. Moreover, the amorphous elastin was distributed preferentially in small islands rather than in laminae (p less than 0.05). Twenty-eight days after monocrotaline injection, medial and right ventricular hypertrophy had developed (p less than 0.05 and p less than 0.01, respectively). At the same time, there was a striking increase in both insoluble elastin synthesis and total insoluble elastin content (p less than 0.01 for both) and an increase in collagen synthesis and total collagen content (p less than 0.05 for both). In addition, the ratio of insoluble elastin synthesis to collagen synthesis was greater than in controls (p less than 0.01), whereas the ratio of total insoluble elastin to total collagen did not change. On ultrastructural analysis, the proportion of amorphous elastin in the vessel wall relative to other elements remained low (p less than 0.01) and was distributed throughout the media as increased numbers of small islands (p less than 0.01).(ABSTRACT TRUNCATED AT 400 WORDS)
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