PubMed Health⌕ Search

Biomedical subjects

G Constantopoulos

Publications and source records attributed to G Constantopoulos.

At least 37 records · Page 2Linked to original sources
PubMed1977

Effects of reserpine on water, cation, and norepinephrine contents of cardiovascular tissues of normotensive dogs.

Six adult male mongrel dogs were treated orally with reserpine (0.03 mg/kg) for 6 weeks, after which time the arterial tissue content of water, cations (sodium, potassium, magnesium, and calcium), and norepinephrine was determined and compared with those of six untreated dogs. Reserpine administration resulted in sustained decreases in the mean arterial blood pressure and heart rate, and the arterial tissues of the treated dogs contained less potassium, calcium, and magnesium, the last-named being affected most, but the sodium remained the same. Arterial norepinephrine content was significantly decreased. There was a slight but significant increase in plasma magnesium, without any noticeable changes in other plasma cations. The reduction in the arterial magnesium by reserpine may help to regulate vascular tone and (or) vascular reactivity.

Animals↗
PubMed1976

Mucopolysaccharidosis type V. (Scheie syndrome). A postmortem study by multidisciplinary techniques with emphasis on the brain.

Multidisciplinary studies were conducted on the brain and other tissues of patients who died with the antemortem diagnosis of mucopolysaccharidosis (MPS) of one of the following types; type V, Scheie disease (MPS-V); type I, Hurler disease (MPS-I): and type II, Hunter disease (MPS-II). The principal new finding in the brain of the patient with MPS-V is the presence of lesions in the periadventitial mesenchymal tissue of the white matter, similar to those of MPS-I, while the nerve cells in MPS-V are histologically normal, in contradistinction to MPS-I, in which the neuronal abnormality is severe. Electron microscopical studies of the brain in MPS-I demonstrated numerous complex membranous inclusions in the neurons, whereas the neurons in MPS-V contained only a small number of lipofuscin-like inclusions and typical lipofuscin granules. There was a threefold increase of glycosaminoglycans (GAG) in the brain of MPS-I, but only a slight increase in the MPS-V; GAG in the liver and spleen of all patients was noticeably increased. alpha-L-iduronidase activity was not detectable in the brain and liver of patients with MPS-I and MPS-V, thus suggesting a similar enzymatic defect.

Adult↗
PubMed1975

Chemical definition of the mucopolysaccharidoses.

Glycosaminoglycans were isolated from the urines of 46 patients with mucopolysaccharidosis; 11 with Type I (Hurler), 8 with Type II (Hunter), 16 with Type III (Sanfilippo A and B), 9 with Type V (Scheie), one with Type VI (Marateaux-Lamy), and one unclassified. All 46 patients excreted in their urine excessive amounts of dermatan sulfate, heparan sulfate or both. In addition, patients of certain types excreted excessive amounts of chondroitin sulfates A and/or C. There is a trend in each type of the disease towards the same carbazole/orcinol ratio, glucosamine/galactosamine ratio and glycosaminoglycan composition. Molecular weight distribution of the urinary glycosaminoglycans by gel filtration from Sephadex G-200 is characteristic for each different type of mucopolysaccharidosis and is distinguished from normal controls and patients without mucopolysaccharidosis. Preparation of elution diagrams from Sephadex G-200 allows an estimation of the composition of the glycosamino-glycans. Practically all heparan sulfate and a sizable part of dermatan sulfate from the urinary glycosaminoglycans of all these patients have been highly degraded. In all the patients in which the specific enzyme defect was demonstrated, the assignment of the type of mucopolysaccharidosis, on the basis of the elution diagrams, was correct. Patients with mucopolysaccharidosis Type V displayed two conspicuously different types of elution patterns, suggesting heterogeneity. Indeed, only a portion of these patients showed alpha-L- iduronidase deficiency. Carriers had normal urinary glycosaminoglycan output and composition and exhibited normal elution diagrams.

Adolescent↗
PubMed1975

Water, cations, and norepinephrine content of cardiovascular tissues of unilaterally nephrectomized dogs treated with deoxycorticosterone and NaCl.

Deoxycorticosterone pivalate (2.5 mg/kg) given intramuscularly on four occasions 10-15 days apart over a period of 45 days to unilaterally nephrectomized adult male mongrel dogs, receiving as drinking solution 0.9% NaCl in 5% dextrose, resulted in an average sustained rise in the mean arterial blood pressure of 30 mm Hg (1 mm Hg - 133 N/m2) in 60% of the animals. Hypertensive dogs had in their arterial tissues generally more sodium, potassium, magnesium, and calcium than the similarly treated but non-hypertensive dogs, but compared to the tissues of operated untreated or unoperated normotensive dogs, only sodium and calcium were significantly higher. The dogs who were similarly treated but did not develop hypertension had in their arterial tissues less sodium, potassium, and magnesium than operated untreated or unoperated normotensive dogs. Norepinephrine content in the branches of mesenteric arteries of all deoxycorticosterone- and NaCl-treated animals, irrespective of their blood pressure, was significantly lower, and in the myocardium significantly higher, than either the unoperated normotensive or operated but not further treated dogs. It is concluded, therefore, that in deoxycorticosterone + NaCl treatment the dogs which developed hypertension had more arterial sodium, potassium, magnesium, and calcium than those who were similarly treated but remained within the limits of normal blood pressure, and that there was no difference between hypertensive and non-hypertensive dogs in regard to their cardiovascular norepinephrine content.

Animals↗
PubMed1975

Arterial water, cations, and norepinephrine in early and late renovascular hypertension.

In dogs made hypertensive renal artery stenosis and contralateral nephrectomy, the arterial and myocardial tissue content of water, cations (sodium, potassium, magnesium, calcium), and norepinephrine was measured 20 and 60 days after the operation. Hypertensive animals autopsied at the earlier stage of hypertension had significantly lower (-25 to-50%, P smaller than 0.01) arterial norepinephrine than either the sham or nonhypertensive animals. The water and cation content of arteries was unchanged, but aortic tissue contained significantly more water, sodium, potassium, and magnesium than the nonhypertensives. Hypertensives autopsied at 60 days also had lower arterial norepinephrine content than sham and nonhypertensive animals, but this refuction was not significant. Their arterial and aortic tissue contained more water and cations than the nonhypertensive, sham, unoperated, and unilaterally nephrectomized dogs. It is suggested that in the initial stage of renovascular hypertension the arterial norepinephrine content is reduced significantly, whereas at a later stage the arterial water and cations may be involved in the maintenance of an elevated blood pressure.

Animals↗