PubMed Health⌕ Search

Biomedical subjects

S M Fitzgerald

Publications and source records attributed to S M Fitzgerald.

25 records · Page 2Linked to original sources
PubMed1997

Systemic hemodynamic responses to chronic angiotensin II infusion into the renal artery of dogs.

Chronic intrarenal infusion of angiotensin II (0.5 ng.kg-1.min-1) in dogs increases arterial pressure. In the present study we determined whether this was associated with changes in cardiac output or in total peripheral resistance. Mean arterial pressure did not change initially but was significantly increased over days 14-28 of the infusion period (+6 +/- 2 mmHg), as was total peripheral resistance (+4 +/- 2 mmHg.min.l-1). Neither cardiac output, renal blood flow, nor glomerular filtration rate was significantly changed over this period. To determine the influence of the autonomic nervous system on the developing hypertension, periodic acute autonomic ganglion blockade was performed. Before angiotensin II infusion ganglion blockade reduced total peripheral resistance and increased cardiac output, and this effect was similar across the 4 wk of angiotensin II infusion. Systemic hemodynamics were not affected by intravenous angiotensin II infusion (0.5 ng.kg-1.min-1). Thus intrarenal infusion of low-dose angiotensin II produced a chronic increase in arterial pressure due to an action within the kidney. The hypertension was associated with increased total peripheral resistance but not with marked changes in cardiac output or renal function or in the influence of the autonomic nervous system on systemic hemodynamics.

Angiotensin II↗
PubMed1997

Low dose angiotensin II infusions into the renal artery induce chronic hypertension in conscious dogs.

Angiotensin II was infused at 0.5 ng/kg/min either directly into the left renal artery (n = 5) or intravenously (n = 4) for 28 days in conscious dogs. Renal artery infusion of angiotensin II had no significant effect on mean arterial pressure after 1 and 24 h, but pressure had increased by 12 +/- 2, 12 +/- 4, 8 +/- 3 and 13 +/- 3 mmHg on days 7, 14, 21 and 28, respectively, during infusion. Renal blood flow decreased significantly at 24 hours (p = 0.02) but was not significantly reduced subsequently. Over days 7-28, central venous pressure and haematocrit rose significantly but body weight did not change significantly. During intravenous infusion of angiotensin II, arterial pressure increased (5 +/- 4, 7 +/- 5 and 5 +/- 3 mmHg on days 7, 14 and 21, respectively), body weight rose and haematocrit fell significantly, but central venous pressure did not change. Thus, angiotensin II infused into the renal artery, at a dose which had no initial pressor effect, produced chronic, stable hypertension, with equivocal evidence of renal fluid retention. We conclude that elevated levels of angiotensin II in the kidney alone can cause chronic hypertension.

Angiotensin II↗
PubMed1995

Nitric oxide synthase blockade and renal vascular responses to norepinephrine and endothelin-1 in conscious dogs.

The effects of inhibiting nitric oxide (NO) synthase with NG-nitro-L-arginine (L-NNA) on renal vasoconstrictor responses to intrarenally administered norepinephrine (NE) and endothelin-1 (ET-1) were studied in conscious dogs. NE was infused into the renal artery at 0.02, 0.05, 0.1, and 0.2 micrograms/kg/min (15 min at each rate), with the dogs (n = 5) pretreated with either L-NNA 10 mg/kg intravenously (i.v.) or vehicle (250 mM NaHCO3 solution at 2 ml/kg i.v.) NE produced dose-related decreases in renal blood flow (RBF) and renal vascular conductance that were significantly greater after L-NNA pretreatment than after vehicle. ET-1 was infused intrarenally at 2.7 ng/kg/min for 45 min with the dogs (n = 5) pretreated with either L-NNA 10 mg/kg i.v. or vehicle. ET-1 caused a progressive decrease in RBF and renal vascular conductance. In contrast to the results with NE, RBF and renal vascular conductance decreased significantly less in response to ET when the dogs were pretreated with L-NNA as compared with pretreatment with vehicle. Therefore, blockade of NO synthase augmented NE-induced but not ET-induced renal vasoconstriction. The results therefore suggest that NO may act to lessen the renal vascular effects of NE, but this effect does not appear to be generalised to all vasoconstrictors.

Animals↗
PubMed1990

The educational value of clinical electives.

One hundred and eighty-four medical students at the University of Queensland were surveyed after they returned from their clinical elective. Approximately half stayed in Australia, and the other half travelled overseas. The United Kingdom was the most popular overseas destination, but there was a wide geographic distribution. The most popular clinical specialties were surgery, medicine, orthopaedics and emergency medicine, while the least popular were geriatrics and psychiatry. They were given a reasonable work schedule, but students remaining in Australia had a heavier work-load. While students on overseas electives received more formal instruction, students remaining in Australian placements received greater responsibility and better acceptance, but the majority in both groups received adequate supervision. Students gained experience in a large number of practical procedures, especially those in Australian placements. More problems were encountered by students in overseas placements, particularly with regard to organizing the elective, finances and personal-social difficulties. The vast majority of students found their clinical elective to be moderately or extremely worthwhile, and cited a number of perceived benefits. These results suggest that the clinical elective can have significant educational value.

Attitude of Health Personnel↗
PubMedDate not supplied

Effects of long-term intrarenal angiotensin II infusion on renal vascular responsiveness to vasoactive agents.

1. We tested whether chronic intrarenal angiotensin II (AngII) infusion altered renal vascular responsiveness to vasoactive agents, which would provide evidence of vascular structural changes. 2. The renal blood flow (RBF) responses to renal arterial administration of bolus doses of acetylcholine, glyceryl trinitrate, AngII and noradrenaline were measured before commencement of and 1 day after cessation of 28 days intrarenal AngII infusion (0.5 ng/kg per min) in chronically instrumented conscious dogs. 3. The RBF responses to these vasoactive agents were unaltered by chronic intrarenal AngII infusion in conscious dogs. 4. These functional studies provide no evidence for renal vascular hypertrophy in response to chronic intrarenal AngII infusion in conscious dogs.

Acetylcholine↗
PubMedDate not supplied

Advanced practice nursing: back to the future.

Advanced practice nursing has evolved during the last 25 years in important ways to become a central component of the new health care system. The quality of care and cost effectiveness of practice for various advanced practice roles has been well documented. New roles are being created as the demand-driven health care system presents opportunities for innovative practice models. It is incumbent on nursing to prove its ability to assume full accountability and responsibility so that full freedom to practice may be achieved.

Forecasting↗