Biomedical subjects

M McClanahan

Publications and source records attributed to M McClanahan.

6 recordsLinked to original sources

PubMed1996

Advanced practice nurses: change agents for clinical practice.

The article presents the role of advanced practice nurses as change agents in the clinical setting. Research utilization is needed to shape and form the basis of nursing practice. As change agents, the advanced practice nurses in one institution established a research-based minimal stimulation protocol for the very low-birth weight infant and implemented it using a video presentation. Knowledge of change theory, research utilization, and video production was necessary in making this project a success.

Clinical Nursing Research↗

PubMed1985

Dopaminergic regulation of natriuretic response to acute volume expansion in dogs.

Effects of carbidopa, a dopa (3,4-dihydroxyphenylamine) decarboxylase inhibitor, on the renal, haemodynamic and hormonal responses to acute volume expansion were examined in six healthy mongrel dogs which were infused intravenously with 0.9% sodium chloride solution (saline; 30 ml h-1 kg-1) over 2 h. Saline infusion studies were performed in the absence (control) and in the presence of carbidopa given by nasogastric tube in a dose of 1 mg/kg every 8 h beginning 24 h before the infusion. Saline infusion resulted in an increase in renal excretion of dopamine (3,4-dihydroxyphenylethylamine) and a decrease in renal excretion of noradrenaline. Carbidopa treatment decreased urinary sodium excretion and eliminated the increase in renal production of dopamine in response to saline infusion without affecting renal or haemodynamic response to acute vascular volume expansion with saline. Carbidopa treatment obliterated the suppression of aldosterone produced by saline infusion. Thus, dopamine appears to play a significant role in mediating both the natriuretic and aldosterone response to acute volume expansion.

Aldosterone↗

PubMed1984

Relationship between urinary dopamine production and natriuresis after acute intravascular volume expansion with sodium chloride in dogs.

The role of renal production of dopamine in mediating the natriuretic response to acute vascular volume expansion was investigated. The effect of infusion of 0.9% saline (30 ml/kg X h) over 2 h on urine excretion of sodium and catecholamines, as well as other hemodynamic and renal function parameters, was examined in seven dogs during control and carbidopa (1 mg/kg every 8 h for 24 h before saline infusion) treatment periods. Acute vascular volume expansion with saline resulted in a rise (P less than 0.01) in the renal excretion of dopamine and a depression (P less than 0.01) in renal excretion of norepinephrine which paralleled the natriuretic response to saline infusion. Epinephrine excretion was not altered by saline infusion. Carbidopa treatment was not associated with changes in left ventricular filling pressure, arterial blood pressure, glomerular filtration rate, renal blood flow, renal excretion of norepinephrine or epinephrine. However, carbidopa eliminated the increase in renal production of dopamine and markedly attenuated the natriuretic response to saline infusion. Since carbidopa blocks tissue conversion of dopa to dopamine, it appears that renal production of dopamine is an important mechanism mediating the natriuretic response to acute volume expansion.

Animals↗

PubMed1984

Effect of clonidine therapy on renal hemodynamics in renal transplant hypertension.

Antihypertensive medications have a variable effect on renal hemodynamics and may contribute to renal insufficiency in some patients. Since clonidine has actually been found to improve renal hemodynamics in patients with essential hypertension, we studied the effects of clonidine therapy in patients with renal transplant hypertension. Baseline measurements of BP and renal hemodynamics were made in six patients after two weeks of therapy with furosemide. Clonidine was then added and titrated until BP was controlled. Repeated measurements of renal hemodynamics were made four and 16 weeks after clonidine therapy was begun. Glomerular filtration and effective renal plasma flow as assessed by inulin and aminohippurate sodium clearances were preserved during prolonged clonidine therapy.

Adult↗

PubMed1978

Patterns of RNA synthesis in early meiotic prophase oocytes from fetal mouse ovaries.

In a study of the early meiotic prophase stages of mouse oogenesis from d12 of gestation to 10d post-partum the patterns of RNA synthesis during these stages of oogenesis using H3-uridine incorporation as visualized by light microscope autoradiography are reported. We find that chromosomal RNA synthesis occurs in all stages except early to mid-pachytene, the time of maximum chromosome condensation. Diplotene and dictyate nuclei are the most heavily labelled stages. Nucleolar labelling ceases before leptotene and reappears in late pachytene or early diplotene, even though nucleoli can be identified in all stages except early to mid-pachytene.

Animals↗

PubMedDate not supplied

Catecholamine, renin, aldosterone, and arginine vasopressin responses to lower body negative pressure and tilt in normal humans: effects of bromocriptine.

We have examined the effects of the dopamine agonist bromocriptine (BEC) on the hormonal and hemodynamic response to graded lower body negative pressure (LBNP) and tilting in five normal volunteers. BEC blunted the plasma norepinephrine (NE), plasma renin activity (PRA), and aldosterone responses to both LBNP and tilting. The inhibitory effects of BEC on the plasma NE response to these maneuvers are likely mediated through presynaptic inhibition of peripheral neuronal release of NE as well as central nervous system effects of the drug. Since the PRA responses to LBNP and tilting are likely mediated through beta-adrenoreceptor stimulation, BEC probably indirectly blunts the PRA and aldosterone responses to those maneuvers through its inhibitory effects on NE secretion. BEC treatment resulted in a hypotensive response to tilting that was accompanied by a rise in plasma potassium and arginine vasopressin (AVP). No such rises in plasma potassium and AVP are observed, in the absence of BEC treatment, following graded LBNP and tilting. The rise in plasma potassium with tilting (BEC treatment) probably resulted from blunting of the NE rise. Thus, the rise in plasma NE may play an important role in preventing a rise in plasma potassium in association with LBNP and orthostatic stress. AVP levels in normal men are not responsive to unloading of cardiopulmonary and sinoaortic baroreceptors. It is only after overt hypotension is produced--as after BEC treatment--that plasma levels of AVP rise.

Adult↗