Molecular cloning and sequence analysis of a chondroitin sulfate proteoglycan cDNA.

We report the identification and DNA sequence of a chondroitin sulfate proteoglycan core protein cDNA. A cDNA clone, pPG1, was selected from a rat yolk sac tumor poly(A)+RNA-derived cDNA library by using synthetic oligonucleotides predicted from the NH2-terminal peptide sequence of the mature chondroitin sulfate proteoglycan. The resulting sequence analysis demonstrated that the 874-base-pair pPG1 clone contained the complete coding region of the mature proteoglycan core protein as well as 5' and 3' flanking sequences. The 104 amino acid proteoglycan core protein sequence reveals that the core protein is composed of three regions, the most striking of which is the central 49 amino acid region composed of alternating serine and glycine residues. This region clearly functions as the acceptor site for the attachment of chondroitin sulfate side chains. The serine-glycine repeat region is flanked by a 14 amino acid NH2-terminal region identical to the NH2-terminal sequence of the proteoglycan obtained by amino acid sequencing and a 41 amino acid COOH-terminal region. RNA transfer blot hybridizations of poly(A)+ mRNA from rat yolk sac tumor cells with nick-translated pPG1 reveal a single mRNA of approximately equal to 1300 nucleotides. The possibility of detecting mRNAs and genomic sequences for other proteoglycans with a serine-glycine repeat by using this cDNA clone is discussed.     

Effects of carbohydrate type on postprandial blood pressure,neuroendocrine and gastrointestinal hormone changes in the elderly

Previous studies have demonstrated that blood pressure falls postprandially in fit elderly subjects, the greatest changes occurring after meals with a high carbohydrate content. To evaluate the influence of the type of carbohydrate on postprandial blood pressure, the effects of equivalent energy content (2.4 MJ) high complex (starch) and high simple (monosaccharide) carbohydrate meals were studied in seven healthy elderly subjects. Blood pressure, heart rate, autonomic function, plasma catecholamines, insulin and neurotensin levels were measured pre- and postprandially. Greater falls in supine and erect systolic blood pressure occurred after the high simple than the high complex carbohydrate meal (p < 0.05). No differences were found in supine or erect diastolic blood pressure, heart rate or in any of the biochemical parameters measured between the meal types. It is concluded that a simple carbohydrate meal results in a greater postprandial fall in blood pressure than an equivalent energy complex carbohydrate meal in the elderly, although the mechanisms for these changes are unknown.     

Value of non-invasive continuous blood pressure monitoring in the detection of carotid sinus hypersensitivity

A patient with recurrent episodes of dizziness and blackouts is described. Detailed cardiac and neurological investigations were normal. Autonomic assessment excluded postural hypotension and confirmed normal sympathetic vasoconstrictor function. Cardiac parasympathetic function in response to deep breathing, hyperventilation and ocular pressure was normal. Left carotid sinus massage only reproducibly lowered blood pressure with minimal change in heart rate. This occurred mainly during head-up tilt. The fall in blood pressure was not affected by the muscarinic blocker atropine, or the peptide release inhibitor, octreotide. A diagnosis of left carotid sinus hypersensitivity of the vasodepressor variety was made. Left carotid sinus denervation was performed. This successfully prevented further episodes of dizziness and blackouts. The ability to measure beat-to-beat blood pressure non-invasively was of particular importance in diagnosis, and in the assessment of management options in this patient.     

The antiatherogenic effects of components isolated from pollen Typhae

Based on the results of previous investigations that pollen Typhae, a Traditional Chinese Medicine, Had antiatherogenic effects, several components were isolated successively from the drug and their effects on porcine aortic endothelial cell (EC) and smooth muscle cell (SMC) cultures as well as on platelet aggregation were examined. 12 components isolated from Pollen Typhae have been identified on their chemical structures and biological effects. 4 of them showed different evident antiatherogenic effects. 1) Isorhamnetin-3-O-rhamnosyl-glucoside could stimulate EC to produce tPA and PGI; 2)Quercetin-3-O-neohesperidose could protect EC from injury by fibrin, as well as raise tPA activity; 3)β-Sitosterol palmitate could inhibit SMC proliferation and 4) β-Sitosterol glucoside showed an inhibitory effect on platelet aggregation. These results would provide some information for the search of new drugs in the treatment and prevention of atherosclerosis.