Search PubMed⌕ Search

Biomedical subjects

S G Rockson

Publications and source records attributed to S G Rockson.

29 records · Page 2Linked to original sources
PubMed1997

Lymphedema: anatomy, physiology and pathogenesis.

The authors review the current understanding of lymphatic anatomy and physiology, and the pathophysiology of lymphedema. The skin lymphatic system consists of the initial lymphatics, which converge into lymphatic precollectors, collectors and lymphatic ducts; these in turn convey the lymph to the regional lymph nodes. Interstitial fluid and particles enter the initial lymphatics through interendothelial openings and by vesicular transport. Lymphatic uptake is enhanced by external compression. Lymphatic transport depends greatly on contraction of lymphangions, which generate the suction force that promotes absorption of interstitial fluid and expels lymph to collecting ducts. In lymphedema, various types of congenital and acquired abnormalities of lymphatic vessels and lymph nodes have been observed. These often lead to lymphatic hypertension, valvular insufficiency and lymphostasis. Accumulation of interstitial and lymphatic fluid within the skin and subcutaneous tissue stimulates fibroblasts, keratinocytes and adipocytes eventuating in the deposition of collagen and glycosaminoglycans within the skin and subcutaneous tissue together with skin hypertrophy and destruction of elastic fibers.

Collagen↗
PubMed1996

A novel therapy for lymphedema complicated by lymphorrhea.

Lymphorrhea is a rarely described complication of chronic lymphedema, in which the disrupted flow through diseased lymphatic channels gives rise to the external drainage of lymph, often heralded by the presence of an enlarging lymphocele. This report documents the applicability of the Reid sleeve, a novel, conservative form of therapy, in an unusually severe and protracted example of lymphorrhea.

Bandages↗
PubMed1985

Pregnancy-associated group B streptococcal endocarditis: a report of two fatal cases.

Group B streptococci commonly colonize parturient women, yet pregnancy-associated endocarditis due to this organism is rare. Most reports of group B streptococcal endocarditis are from the preantibiotic era and occurred in women with rheumatic mitral valve disease. Reported herein are two cases of fatal group B streptococcal endocarditis involving the aortic valve of women with no preexisting heart disease. One had undergone a second-trimester abortion and the other had a normal pregnancy and uncomplicated vaginal delivery.

Abortion, Induced↗
PubMed1982

An antiidiotypic antibody that recognizes the beta-adrenergic receptor.

Antialprenolol rabbit antibodies were fractionated on an acebutolol affinity resin, followed by L-propranolol elution so as to separate a class of binding sites that mimic the beta-adrenergic receptor. Allotype-identicaL rabbits were immunized with this fraction. After 6 mo, antisera exhibited antiidiotypic activity inhibiting [3H]alprenolol binding to the original antibody and to rabbit antiacebutolol antibodies, which had a spectrum of ligand-binding properties identical to the original idiotype. Those antisera demonstrating the original idiotype. Those antisera demonstrating the most potent antiidiotypic activity also blocked [3H]alprenolol binding to the beta-adrenergic receptor of turkey membrane, canine pulmonary membrane, and rat reticulocyte. An idiotype affinity-purified fraction showed similar activity, inhibiting beta-receptor binding with a calculated dissociation constant (KD) of 53 nM. Isoproterenol-mediated adenylate cyclase activity was also inhibited in a competitive manner. The universality of recognition of these antiidiotypic antisera indicate that the three-dimensional structure of a receptor's binding site can be modeled by a subset of an elicited antibody population.

Acebutolol↗
PubMed1981

Cellular mechanisms of impaired adrenergic responsiveness in neonatal dogs.

The myocardial responsiveness of conscious, instrumental dogs to exogenously administered isoproterenol and norepinephrine was investigated in neonatal, 6-wk-old, and adult animals. Comparable base-line values for peak left ventricular derivative of pressure with respect to time were observed in all age categories. However, when compared with adult responses, the sympathomimetic amine-induced increases in neonatal left ventricular dP/dt were significantly blunted at each concentration of adrenergic agonist examined, whereas the 6-wk-old puppies displayed an intermediate inotropic response. To investigate the cellular mechanisms of this blunted neonatal response, we correlated physiologic and biochemical measurements of the myocardial responses to catecholamines in each age category. When compared with adult myocardial membrane preparations, neonatal cardiac membranes were characterized in vitro by an increased density of beta-adrenergic binding sites, comparable affinity for adrenergic agonists and antagonists, and an enhanced coupling of adenylate cyclase activation to receptor occupancy. Simultaneous changes in either the serum catecholamine concentration or the membrane content of other intrinsic proteins failed to account for the observed neonatal increase in beta-adrenergic receptor density. These findings are most consistent with a compensatory mechanism of the cardiac cell membrane, whereby an inherent depression in the adrenergic responsiveness of the immature myocardium appears to induce the increase in receptor density and activation of adenylate cyclase.

Adenylyl Cyclases↗
PubMed1980

Anti-alprenolol antibodies in the rabbit. A new probe for the study of beta-adrenergic receptor interaction.

We immunized rabbits with an antigen prepared by covalent linkage of alprenolol, a beta-adrenergic receptor antagonist, to bovine serum albumin. Competitive inhibition of [3H]dihydroalprenolol binding to antisera with a variety of unlabeled ligands revealed broad antibody specificity for beta-adrenergic antagonists and agonists. The antiserum was subjected to affintiy fractionation on hydroxybenzylpindolol-Sepharose 4B. Successive elution with 100 mM Tris HCl, 1M NaCl, 4 M LiBr, and 5 M guanidine yielded fractions with increasing affintiy for hydroxybenzylpindolol. The ligand-binding properties of these affinity-fractionated antibodies suggest that certain of these fractions recognize structural aspects of individual beta-adrenergic ligands which are irrelevant to their biological activity, whereas others can be used to distinguish shared functional properties, such as the ethanolamine side chain, within the structural heterogeneity of beta-adrenergic drugs. In particular, elution of hydroxybenzylpindolol-adsorbed antibody with (-)-propranolol allowed identification of an antibody fraction specific for the (-)-stereoisomer. Thus, affinity fractionation of antibodies raised against beta-adrenergic ligands can provide useful analogues for the further study of the recognition properties of the beta-adrenergic receptor.

Alprenolol↗
PubMed1976

Plasma dopamine-beta-hydroxylase in the diagnosis of neuroblastoma.

An atypical case of neuroblastoma is described, in which the diagnosis was facilitated by the application of a new biochemical procedure, the assay of plasma dopamine-beta-hydroxylase activity. This laboratory tool is proposed as a useful adjunct to established techniques in the diagnosis of neural crest tumors.

Adolescent↗
PubMed1975

Plasma dopamine-beta-hydroxylase activity in oral contraceptive hypertension.

A prospective study was undertaken to evaluate the relative contribution of changes in sympathetic nervous system activity, as reflected by changes in dopamine-beta-hydroxylase (DBH) activity, to the pathogenesis of oral contraceptive-induced hypertension. Precontraceptive and serial post contraceptive determinations of blood pressure, plasma renin activity (PRA), DBH activity, and changes in body weight were obtained in twelve control patients and forty-one oral contraceptive users. Forty-four percent of oral contraceptive users had increases in blood pressure but remained normotensive and 17% became frankly hypertensive. The precontraceptive and average post contraceptive levels of mean arterial pressure (MAP), PRA and DBH activity in each patient were compared using paired group analysis. Control patients (group I) exhibited no significant changes in these variables, while the patients with contraceptive-induced increases in MAP (groups III and IV) underwent significant, parallel increases in DBH activity. Finally, the linear regression of changes in MAP on the percent change in DBH activity was examined. The positive slopes in groups III and IV differed significantly from the negative slope of the controls (group I). The data have been interpreted to reflect an inappropriate oral contraceptive-induced stimulus to sympathetic nervous system activity, leading to increases in MAP in susceptible individuals.

Adult↗