Search PubMed⌕ Search

Biomedical subjects

C Frampton

Publications and source records attributed to C Frampton.

At least 37 records · Page 2Linked to original sources
PubMed1999

Neuroendocrine prediction of left ventricular function and heart failure after acute myocardial infarction. The Christchurch Cardioendocrine Research Group.

OBJECTIVE: To determine the relations of plasma levels of brain natriuretic peptide (BNP), atrial natriuretic factor (ANF), N-terminal ANF (N-ANF), cyclic guanosine monophosphate (cGMP; the cardiac peptide second messenger), and plasma catecholamines to left ventricular function and to prognosis in patients admitted with acute myocardial infarction. DESIGN: Plasma hormones and ventricular function (radionuclide ventriculography) were measured 1-4 days after myocardial infarction in 220 patients admitted to a single coronary care unit. Radionuclide scanning was repeated 3-5 months after infarction. Clinical events were recorded over a mean period of 14 months. RESULTS: Both early and late left ventricular ejection fraction (LVEF) were most closely related to plasma BNP (r = -0.60, n = 220, p < 0.001; and r = -0.53, n = 192, p < 0.001, respectively), followed by ANF, N-ANF, cGMP, and the plasma catecholamines. Early plasma BNP concentrations less than twofold the upper limit of normal (20 pmol/l) had 100% negative predictive value for LVEF < 40% at 3-5 months after infarction. In multivariate analysis incorporating all the neurohormonal factors, only BNP remained independently predictive of LVEF < 40% (p < 0.005). Survival analysis by median levels of candidate predictors identified BNP as the most powerful discriminator for death (p < 0.0001). No early deaths (within 4 months) occurred in patients with plasma BNP concentrations below the group median (27 pmol/l), and over follow up only three of 26 deaths occurred in this subgroup. Of all episodes of left ventricular failure, 85% occurred in patients with plasma BNP above the median (p < 0.001). In multivariate analyses, BNP alone gave additional predictive information beyond sex, age, clinical history, LVEF, and plasma noradrenaline for both subsequent onset of LVF and death. CONCLUSIONS: Plasma BNP measured within 1-4 days of acute myocardial infarction is a powerful independent predictor of left ventricular function, heart failure, or death over the subsequent 14 months, and superior to ANF, N-ANF, cGMP, and plasma catecholamines.

Atrial Natriuretic Factor↗
PubMed1998

Plasma N-terminal pro-brain natriuretic peptide and adrenomedullin: new neurohormonal predictors of left ventricular function and prognosis after myocardial infarction.

BACKGROUND: Newly discovered circulating peptides, N-terminal pro-brain natriuretic peptide (N-BNP) and adrenomedullin (ADM), were examined for prediction of cardiac function and prognosis and compared with previously reported markers in 121 patients with myocardial infarction. METHODS AND RESULTS: The association between radionuclide left ventricular ejection fraction (LVEF) and N-BNP at 2 to 4 days (r=-.63, P<.0001) and 3 to 5 months (r=-.58, P<.0001) after infarction was comparable to that for C-terminal BNP and far stronger than for ADM (r=-.26, P<.01), N-terminal atrial natriuretic peptide (N-ANP), C-terminal ANP, cGMP, or plasma catecholamine concentrations. For prediction of death over 24 months of follow-up, an early postinfarction N-BNP level > or = 160 pmol/L had sensitivity, specificity, positive predictive value, and negative predictive values of 91%, 72%, 39%, and 97%, respectively, and was superior to any other neurohormone measured and to LVEF. Only 1 of 21 deaths occurred in a patient with an N-BNP level below the group median (Kaplan-Meier survival analysis, P<.00001). For prediction of heart failure (left ventricular failure), plasma N-BNP > or = 145 pmol/L had sensitivity (85%) and negative predictive value (91%) comparable to the other cardiac peptides and was superior to ADM, plasma catecholamines, and LVEF. By multivariate analysis, N-BNP but not ADM provided predictive information for death and left ventricular failure independent of patient age, sex, LVEF, levels of other hormones, and previous history of heart failure, myocardial infarction, hypertension, or diabetes. CONCLUSIONS: Plasma N-BNP measured 2 to 4 days after myocardial infarction independently predicted left ventricular function and 2-year survival. Stratification of patients into low- and high-risk groups can be facilitated by plasma N-BNP or BNP measurements, and one of these could reasonably be included in the routine clinical workup of patients after myocardial infarction.

Adrenomedullin↗
PubMed1998

A diet rich in walnuts favourably influences plasma fatty acid profile in moderately hyperlipidaemic subjects.

OBJECTIVE: To compare two low fat diets one rich in walnuts on parameters of lipid metabolism in a group of hyperlipidaemic subjects. DESIGN: A randomised cross over study. SETTING: Department of Human Nutrition, University of Otago, Dunedin, New Zealand SUBJECTS: Twenty one men with mean (s.d.) levels of total and LDL cholesterol of 6.58 (0.60) and 4.63 (0.58) respectively. INTERVENTIONS: For two periods of four weeks subjects were asked to consume two low fat diets (fat 30% total energy), one containing, on average, 78 g/d walnuts. Walnuts obtained through Lincoln University and the Walnut Growers Group (South Canterbury). RESULTS: Participants reported a higher total fat intake on the walnut diet (38% compared with 30% on the low fat diet P < 0.01) The most consistent change in fatty acid profile of triacylglycerol, phospholipid and cholesterol ester on the walnut diet was a significant (P < 0.01) increase in linoleic acid. Triacylglycerol linolenate also increased significantly (P < 0.01). Total and LDL cholesterol were lower on both experimental diets than at baseline, 0.25 mmol/l and 0.36 mmol/l respectively on the walnut diet and 0.13 mmol/l and 0.20 mmol/l respectively on the low fat diet. High density lipoprotein cholesterol was higher on both the walnut and low fat diets when compared to baseline (0.15 mmol/l and 0.12 mmol/l, respectively). When comparing the walnut and low fat diets only apo B was significantly lower (P < 0.05) on the walnut diet. CONCLUSIONS: Despite an unintended increase in the total fat intake on the walnut diet, fatty acid profile of the major lipid fractions showed changes which might be expected to reduce risk of cardiovascular disease. The reduction of apolipoprotein B suggests a reduction in lipoprotein mediated risk, the relatively low myristic acid content of both diets perhaps explaining the absence of more extensive differences in lipoprotein levels on the two diets.

Adult↗
PubMed1998

Hormone responses to stress in patients with major burns.

The responses of the plasma stress hormones corticotrophin (ACTH), vasopressin (AVP), cortisol and corticotrophin releasing hormone (CRH) have been studied in seven consecutive patients aged between 15 and 65 years who suffered from burns of 15-95% total body surface area. There was a distinct peak in AVP (up to 100 pmol/l) and ACTH levels well above the upper limit of normal in all except one patient within 24 h of burn injury. Following the initial rise, AVP and ACTH tended to fall. Plasma CRH with one exception remained within the normal range. Concurrent measurement of plasma renin activity (PRA), haemoglobin (Hb), haematocrit (Hct) and plasma sodium (Na), to assess hydration, showed that PRA was increased in all except one patient during the first 4 days of hospital admission. The correlation between ACTH and cortisol was highly significant (P < 0.001), as was the correlation between ACTH and AVP, AVP and Na, PRA and Hb, and Hct and Na. Other significant correlations were ACTH and Hct (P = 0.023), ACTH and Na (P = 0.017), AVP and Hct (P = 0.029), CRH (P = 0.018), CRH and Hb (P = 0.001). No significant correlation could be demonstrated between CRH and ACTH or AVP. Our findings suggest that AVP plays a role in the hypercortisolaemia which accompanies major burns. The possible detrimental effect of very high levels of AVP leading to progression of burn depth and reduction of skin graft take by its potent vasoconstrictive action and water retention effect (resulting in oedema) deserves further study. As AVP has the potential to reduce tissue perfusion, the possible use of antagonists in major burns merits further consideration. Persistently raised PRA levels, despite normal biochemical and haematological parameters, may indicate that volume expansion therapy may not be adequate, and that both hypovolaemia and stress may contribute to the AVP response. Stress hormone monitoring may lead to better treatment and a reduction in burn stress.

Adolescent↗
PubMed1996

Effect on lipoprotein profile of replacing butter with margarine in a low fat diet: randomised crossover study with hypercholesterolaemic subjects.

OBJECTIVE: To examine the effect on lipid and lipoprotein concentrations when butter or an unsaturated margarine is used for cooking or spreading in a reduced fat diet. DESIGN: Randomised crossover study with two intervention periods of six weeks' duration separated by a five week washout. SETTING: Community setting in New Zealand. SUBJECTS: 49 volunteers with polygenic hypercholesterolaemia and baseline total cholesterol concentration in the range 5.5-7.9 mmol/l. MAIN OUTCOME MEASURES: Concentrations of total and low density lipoprotein, Lp(a) lipoprotein, high density lipoprotein, apolipoprotein B 100, and apolipoprotein A I. RESULTS: Concentrations of low density lipoprotein cholesterol and apolipoprotein B were about 10% lower with margarine than with butter. Lp(a) lipoprotein and high density lipoprotein cholesterol concentrations were similar with the two diets. CONCLUSION: Despite concerns about adverse effects on lipoproteins of trans fatty acids in margarines, the use of unsaturated margarine rather than butter by hypercholesterolaemic people is associated with a lipoprotein profile that would be expected to reduce cardiovascular risk.

Apolipoprotein A-I↗
PubMed1996

Community acquired pneumonia: aetiology and usefulness of severity criteria on admission.

BACKGROUND: Community acquired pneumonia remains an important cause of hospital admission and carries an appreciable mortality. Criteria for the assessment of severity during admission have been developed by the British Thoracic Society (BTS). A study was performed to determine the sensitivity and specificity of a severity rule based on a modification of the BTS prognostic rules applied on admission, to compare severity as assessed by medical staff with the modified rule, and to determine the microbiological cause of community acquired pneumonia in Christchurch. METHODS: A 12 month study of all adults admitted to Christchurch Hospital with community acquired pneumonia was undertaken. Three hundred and sixteen consecutive patients with suspected community acquired pneumonia were screened for inclusion. Variables obtained from the history, examination, investigations, and initial treatment were examined for association with mortality. RESULTS: Two hundred and fifty five patients met the inclusion criteria. Their mean age was 58 years (range 18-97). A microbiological diagnosis was made in 181 cases (71%), Streptococcus pneumonia (39%), Mycoplasma pneumoniae (16%), Legionella species (11%), and Haemophilus influenzae (11%) being the most commonly identified organisms. Patients had a 36-fold increased risk of death if any two of the following were present on admission: respiratory rate > or = 30/min, diastolic BP < or = 60 mm Hg, urea > 7 mmol/l, or confusion. The severity rule identified 19 of the 20 patients who died and six of eight patients admitted to the intensive care unit as having life threatening community acquired pneumonia. The sensitivity of the modified rule for predicting death was 0.95 and the specificity 0.71. In 47 cases (21%) the clinical team appeared to underestimate the severity of the illness. CONCLUSIONS: The organisms responsible for community acquired pneumonia in Christchurch are similar to those reported from other centres except for Legionella species which were more common than in most studies. The modification of the BTS prognostic rules applied as a severity indicator at admission performed well and could be incorporated into management guidelines.

Adolescent↗
PubMed1996

Differing metabolism and bioactivity of atrial and brain natriuretic peptides in essential hypertension.

Plasma concentrations of both atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are elevated in severe hypertension, acute myocardial infarction, and heart failure. In the current study of individuals with essential hypertension, we have documented the hemodynamic, hormonal, and endocrine effects of infusions of these two peptides given alone or in combination in equimolar doses calculated to induce increments in plasma peptides to concentrations (30 to 60 pmol/L) observed in these disease states. The metabolic clearance rate of ANP (4.56 +/- 0.62 L/min) was greater than that for BNP (3.4 +/- 0.23 L/min, P <.001). Infusions of each cardiac hormone impaired the clearance of coinfused peptide. All peptide infusions enhanced natriuresis (17% to 70% above preinfusion levels versus placebo, 6%; P <.001), lowered blood pressure (10 to 18 mm Hg fall in mean arterial pressure below placebo levels; P <.001), increased hematocrit, suppressed the renin-angiotensin-aldosterone system, and enhanced plasma norepinephrine concentrations. The natriuretic and blood pressure-lowering effects of BNP were twofold to threefold those of ANP. In contrast, ANP-induced increments in plasma and urinary second messenger (cGMP) levels were greater than those for BNP. Both peptides suppressed the renin-angiotensin-aldosterone system (approximately one-third fall in renin activity and plasma aldosterone) and enhanced plasma norepinephrine concentrations (+30%) to a similar degree. Increments in plasma ANP and BNP that occur simultaneously in cardiovascular disease states appear capable of causing hemodynamic, endocrine, and renal effects that would tend to ameliorate conditions such as hypertension or heart failure.

Atrial Natriuretic Factor↗
PubMed1995

Interactions of atrial and brain natriuretic peptides at pathophysiological levels in normal men.

Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are both circulating plasma hormones that are secreted by the heart and have similar physiological effects. We have shown previously that abrupt increases in plasma BNP in normal humans impair the clearance of ANP from plasma and result in additive physiological effects. Because large increases in plasma ANP are reported to have no effect on plasma BNP levels in patients with heart failure, we have studied ANP-BNP interactions in eight normal male subjects receiving background infusions of BNP (2 pmol.kg-1.min-1 for 5 h). Each subject also received a coinfusion of ANP ("active" day, 2 pmol.kg-1.min-1 for 2 h) or vehicle ("placebo" day) using a balanced random order, single-blind design. Metabolic clearance rate of ANP (mean 4.1 +/- 0.6 l/min) and disappearance rate from the plasma (t1/2 3.4 +/- 0.3 min) were similar to values measured previously in the absence of exogenous BNP. In contrast, steady-state plasma BNP levels were reversibly increased (mean BNP increment 10 pmol/l) during the administration of ANP (P = 0.038). Associated with these changes were significant (additive) physiological effects. Thus the addition of ANP increased plasma and urine guanosine 3',5'-cyclic monophosphate (P < 0.001 for both) and lowered systolic blood pressure (P = 0.049). When ANP was coinfused, significant differences were also observed in urine volume (P = 0.001) and sodium excretion (P = 0.043) between the infusion period (when urine volume and sodium excretion were enhanced) and postinfusion period (when values decreased). Taken together, our findings of similar interactions between ANP-BNP and BNP-ANP infusions occurring at pathophysiological concentrations of these two peptides, suggest that the interactions result from dissociation of prebound hormone, presumably from biological or clearance receptors.

Adult↗
PubMed1994

Renal, endocrine, and hemodynamic interactions of atrial and brain natriuretic peptides in normal men.

Brain natriuretic peptide (BNP) is a recently identified hormone that is secreted by the human heart and circulates in plasma with natriuretic, endocrine, and hemodynamic effects similar to those of atrial natriuretic peptide (ANP). To examine the interaction of human BNP with ANP, we studied eight normal men receiving constant infusions of ANP (2.0 pmol.kg-1.min-1 for 5 h), with and without superimposed infusions of BNP (2.0 pmol.kg-1.min-1 for 2 h), using a balanced random-order design. BNP infusions achieved plasma levels of 30-35 pmol/l at 90-120 min and were similar to levels observed in mild heart failure. Metabolic clearance rate of BNP (mean 4.6 +/- 0.4 l/min) and disappearance rate from plasma (t1/2 18.9 min) were similar to values determined previously in the absence of exogenous ANP. In contrast, the addition of BNP induced a progressive and reversible increase (50%) in steady-state plasma ANP. Compared with ANP alone, BNP induced an additional (50%) increase in sodium excretion (P < 0.05) and significant increases in both plasma (P < 0.001) and urine guanosine 3',5'-cyclic monophosphate (P < 0.01). Systolic blood pressure was lowered by the addition of BNP (P < 0.01) and continued to fall after cessation of BNP infusions. Despite this, the response of the renin-aldosterone and sympathetic nervous systems (heart rate and plasma catecholamines) was not significantly different on the two study days. As well as showing additive effects of the two natriuretic peptides, these studies point to important interactions of BNP on ANP metabolism at plasma levels observed in mild heart failure.

Adult↗
PubMed1994

Persistence of sodium monofluoroacetate in livestock animals and risk to humans.

1. Sodium monofluoroacetate (1080), a vertebrate pesticide widely used in New Zealand, was administered orally to sheep and goats at a dose level of 0.1 mg kg-1 body weight to assess risk to humans of secondary poisoning from meat. Blood, muscle, liver, and kidney were analysed for 1080 residues. 2. The plasma elimination half-life was 10.8 h in sheep and 5.4 h in goats. Concentrations of 1080 in muscle (0.042 microgram g-1), kidney (0.057 microgram g-1), and liver (0.021 microgram g-1) were substantially lower than those in plasma (0.098 microgram ml-1) at 2.5 h after dosing. 3. Only traces of 1080 (< 0.002 to 0.008 microgram g-1) were found in sheep tissues after 96 hours. 4. Livestock are normally excluded from areas where 1080 is being used for pest control, reducing the risk of secondary poisoning. Even with accidental exposure to a sublethal dose 1080 would not persist in tissues for more than a few days because it is cleared rapidly from the body. Therefore the occurrence of 1080 in meat intended for human consumption is highly unlikely.

Animals↗
PubMed1993

Brain natriuretic peptide: natriuretic and endocrine effects in essential hypertension.

OBJECTIVE: Documentation of the renal, hormonal and haemodynamic effects and plasma clearance of human brain natriuretic peptide (BNP) given (in a dose inducing increases in plasma BNP concentrations to pathophysiological levels) to patients with essential hypertension. DESIGN: Six male patients with untreated, uncomplicated, mild-to-moderate essential hypertension underwent placebo-controlled single-blind studies in balanced random order. Human BNP (2 pmol/kg per min) and vehicle were given as constant intravenous infusions in a volume of 15 ml/h for 2 h. Continuous recording of intra-arterial blood pressure and heart rate, together with serial blood samples (for hormone assays) and 30-min urine collections, were obtained throughout the studies from 90 min before commencement of infusions to 90 min after completion of infusions. RESULTS: Achieved intra-infusion plasma BNP immunoreactivity (20-30 pmol/l) was similar to levels previously observed in heart failure. Plasma cyclic GMP was increased. Sodium excretion rose to 2.5-fold placebo values. Plasma aldosterone fell to 50% of placebo values. Blood pressure and heart rate were unchanged. The metabolic clearance rate (5.0 +/- 0.4 l/min) and plasma half-life (19.5 min) indicated that BNP has a large volume of distribution (141 +/- 16 litre). CONCLUSIONS: In essential hypertension pathophysiological plasma concentrations of human BNP have significant acute effects promoting natriuresis and suppressing plasma aldosterone. These effects are similar to those of ANP, but the plasma half-life and volume of distribution of BNP are considerably greater than those of atrial natriuretic peptide. These two hormones may play separate complementary roles in fluid volume and blood pressure homeostasis.

Aldosterone↗
PubMed1993

Chronic inhibition of endopeptidase 24.11 in essential hypertension: evidence for enhanced atrial natriuretic peptide and angiotensin II.

AIM: To determine the renal, endocrine and haemodynamic effects of an orally active inhibitor of the neutral endopeptidase EC 3.4.24.11 in essential hypertension. METHODS: Two groups of 12 white male patients with essential hypertension were treated with candoxatril at 25 mg every 12 h (group 1) or at 200 mg every 12 h (group 2) for 5 days in double-blind, placebo-controlled, crossover studies. RESULTS: Candoxatril enhanced natriuresis over the initial 48 h of treatment. Twenty-four-hour diurnal hormone profiles (day 4) showed modest elevations in plasma atrial natriuretic factor (ANF) concentrations and more clear-cut increases in plasma and urinary cyclic GMP. Plasma angiotensin II and aldosterone concentrations were also significantly increased. Plasma catecholamine concentrations were significantly increased by the higher dose of candoxatril. Blood pressure (day 4, 24-h intra-arterial recordings) fell significantly with both doses. The infusions of exogenous ANF and angiotensin II on day 5 showed that candoxatril impaired the metabolic clearance of both ANF and angiotensin II with consequent enhancement of the biological effects of both effector peptides. CONCLUSIONS: Candoxatril augments the effects of ANF and lowers blood pressure in patients with hypertension. However, the antihypertensive effects may be offset by increased angiotensin-aldosterone and sympathetic nervous system activity. The blood pressure response to endopeptidase inhibition in hypertensive patients may depend on the relative effects on humoral vasodilator (including ANF) and vasoconstrictor (including the angiotensin-aldosterone and sympathetic) systems.

Adult↗
PubMed1993

Lipid, lipoprotein and apolipoprotein distributions in an elderly New Zealand population.

The aim of this study was to determine the lipid, lipoprotein and apolipoprotein distribution in an ambulant elderly New Zealand population, and to consider the association between these and other variables (including body mass index, diabetes mellitus, and smoking history) with the prevalence of manifest macrovascular disease in a cross-section analysis. The population sample was randomly selected from the age/sex register of a large urban medical centre in Christchurch, New Zealand. A total of 369 subjects (participation rate 69%) aged 65 years and older were screened for manifest macrovascular disease, diabetes mellitus, smoking status, height and body weight. Levels of plasma total cholesterol, triglycerides, HDL cholesterol, apolipoproteins AI and B, glucose, glycated haemoglobin and fibrinogen were measured. Three way analysis of variance (ANOVA) was used to compare continuous variables across age/sex/macrovascular disease groups. Females had significantly higher levels of total and HDL cholesterol, apolipoproteins AI and B than males. Body mass index showed a significant decrease with increasing age. Macrovascular disease was manifest in 24% of males, and in 26% of females. No direct correlation was seen between any of the measured continuous variables and the presence of macrovascular disease, except for fibrinogen (P < 0.05). No significant association was seen between macrovascular disease and smoking status, nor with a diagnosis of diabetes. In females, the frequency of macrovascular disease was significantly higher amongst those with low (< 1.00 mmol/L) levels of HDL.

Age Factors↗
PubMed1993

Endopeptidase 24.11 inhibition by SCH 42495 in essential hypertension.

The detailed integrated renal, hormonal, and hemodynamic effects of acute (first dose) and established (4 days) inhibition of endopeptidase 24.11 by SCH 42495 (200 mg, every 12 hours) were documented in eight patients with essential hypertension in a double-blind, balanced random-order, crossover study. SCH 42495 suppressed plasma endopeptidase activity (> 90%, P < .001) for the duration of the dosing period. Initially, plasma atrial natriuretic factor levels increased markedly (+123%, P < .01) and remained elevated, although to a lesser extent (+34%, P < .01), with established enzyme inhibition. Cyclic guanosine monophosphate in both plasma and urine remained elevated throughout the treatment period. Significant augmentation of sodium excretion in excess of placebo values (96 +/- 27 mmol sodium, P < .001) was established in the initial 24 hours of dosing but later became attenuated, with a mild antinatriuresis (P < .01) in the latter 3 days of treatment. Blood pressure, heart rate, the renin-angiotensin-aldosterone system, and plasma norepinephrine levels were all initially (first dose) unchanged. With established enzyme inhibition (day 4), however, blood pressure was significantly lower (mean 24-hour values, 9.3 +/- 3/-3.8 +/- 1 mm Hg, P < .05 for both systolic and diastolic pressures) than matched placebo values, whereas heart rate was higher (2.7 +/- 1 beats per minute, P < .01). Mean 24-hour values of plasma renin activity (+33%, P < .05), aldosterone (+36%, P < .05), and norepinephrine (+40%, P < .001) were all clearly increased above placebo values with established enzyme inhibition.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Renal, endocrine, and hemodynamic effects of human brain natriuretic peptide in normal man.

Brain Natriuretic Peptide (BNP) is a recently identified hormone which is secreted by the human heart and circulates in plasma. To determine the effects of pathophysiological levels of human BNP (hBNP), we have studied the integrated renal, hormonal, and hemodynamic response in six normal men receiving 2-h infusions of synthetic hBNP (2.0 pmol/kg.min) or placebo in random order. Steady state levels of hBNP (20-30 pmol/L), achieved at 90-120 min, were similar to levels observed in mild heart failure. Compared to placebo infusions, hBNP induced a greater than 2-fold increase in sodium excretion (P = 0.014) and suppressed plasma aldosterone (P < 0.004) to levels less than 50% of placebo values. These changes were associated with an increase in both plasma (P = 0.028) and urine excretion (P < 0.004) of cGMP. Effects on blood pressure were not statistically significant but increases in both heart rate (P < 0.0001) and plasma albumin (P = 0.007) after cessation of hBNP infusions indicate significant hemodynamic effects of hBNP. High MCR (5.8 +/- 0.7 L/min) yet slow disappearance rate (mean t1/2 22.6 min) indicate that hBNP has a large volume of distribution in humans. These studies show that hBNP, at plasma levels observed in patients with mild heart failure, has potentially important natriuretic, endocrine, and hemodynamic effects which are similar to those observed with comparable infusion rates of ANF.

Adult↗
PubMed1993

Atrial natriuretic factor and changes in the aldosterone response to angiotensin II in sodium depleted dogs.

The effects of physiological shifts in plasma atrial natriuretic factor (ANF) concentrations on angiotensin II/aldosterone relationships during changes in sodium status were assessed in 6 conscious beagle dogs. Incremental infusions of angiotensin II (3, 9 and 27ng/kg/min) were administered on three occasions. The animals were studied in sodium replete and deplete states and on a third occasion, again while sodium deplete, with a background constant low-dose infusion of ANF (1.5pmol/kg/min) sufficient to enhance the low endogenous plasma ANF values observed in sodium depletion to match those observed in the sodium replete state. Sodium depletion caused a leftward shift and steepened the slope of the relationship between achieved arterial angiotensin II concentrations and the plasma aldosterone response. This effect was significantly attenuated (approximately 50%) by the low dose ANF infusions which tended to flatten the slope of the angiotensin II/aldosterone curve (ns) and shifted it significantly to the right (p < 0.05). These data suggest subtle shifts in endogenous levels of plasma ANF, accompanying changes in sodium status, are a major contributor to the associated alterations in angiotensin II/aldosterone relationships. Low dose ANF also significantly reduced the effect of angiotensin II on arterial pressures but did not alter natriuresis.

Aldosterone↗
PubMed1992

A comparison of elderly patients with proximal femoral fractures and a normal elderly population: a case control study.

AIM: To assess the importance of bone density and other risk factors in elderly subjects with hip fractures. METHOD: Thirty-six subjects with femoral neck fracture were compared with 72 community controls in this case control study. Variables compared included: history of falls, previous fracture, body mass index, hand grip strength, blood pressure, medication use, cigarette smoking, alcohol intake, visual acuity, age at menopause, mental status quotient, mobility index and mid thigh circumference. Bone mineral density was measured at the hip (DPA absorptiometer) in the 36 subjects with hip fracture and 36 community controls. RESULTS: Fracture patients had significantly (p < 0.01) reduced bone mineral density at femoral neck (0.64 vs 0.74 g/cm2) and trochanteric regions (0.55 vs 0.66 g/cm2). They also had significantly (p < 0.05) lower body mass index, weaker hand grip strength, smaller mid thigh circumference, reduced mobility and more previous fractures. After controlling for age and sex stepwise logistic regression identified handgrip strength, mobility status and falls in that ranking as risk factors for fracture. Bone mineral density was correlated with mobility status and grip strength. CONCLUSION: Patients with hip fracture have lower bone mineral density than controls. Mobility, grip strength and muscle bulk appear to be important in fracture aetiology and could operate either through bone density or risk of falling.

Accidental Falls↗