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J V Anderson

Publications and source records attributed to J V Anderson.

At least 73 records · Page 4Linked to original sources
PubMed1986

The plasma release of atrial natriuretic peptide in man.

We studied plasma atrial natriuretic peptide (ANP) concentrations in seven normal subjects after the acute intravenous infusion of sodium chloride/potassium chloride solution (saline). Three separate infusions of 6, 12 and 18 ml of saline/kg body weight each significantly increased the circulating concentration of ANP without changes of plasma osmolality or electrolyte concentrations. The mean maximal rise of the plasma ANP concentration after the three saline infusions was significantly correlated (r = 0.74, P less than 0.001) with, but occurred 10-30 min later than, the maximal atrial pressure rise. These observations are in accord with the hypotheses that: (a) ANP is a circulating natriuretic factor; (b) atrial distension is an important stimulus to ANP release in man.

Adolescent↗
PubMed1986

Atrial natriuretic peptide: physiological release associated with natriuresis during water immersion in man.

Thermoneutral water immersion produces a physiological increase of thoracic blood volume, raises central venous pressure and increases urinary sodium excretion by a hitherto ill-understood mechanism. We have investigated whether this enhanced sodium excretion could be mediated by the recently discovered natriuretic factor, atrial natriuretic peptide (ANP). During water immersion there was a highly significant (P less than 0.001) twofold increase of the mean plasma ANP concentration and a doubling of the mean urinary sodium excretion. Both were unchanged during the control experiments. These results are consistent with the hypotheses that ANP is released into plasma in response to central blood volume expansion and that it functions as a natriuretic hormone in normal man under physiological conditions.

Adult↗
PubMed1986

Plasma release of atrial natriuretic peptide in response to blood volume expansion.

The response of plasma atrial natriuretic peptide (ANP) concentration to acute intravascular volume expansion was measured in ten male Wistar rats. An infusion of 3 ml polygelene colloidal solution at 37 degrees C over 45 s produced peak venous pressure rises of 1.5 cm water. A highly significant (P less than 0.001) rise of immunoreactive plasma ANP from 24.4 +/- 2.2 (mean +/- S.E.M.) pmol/l to a peak of 70.0 +/- 10.5 pmol/l occurred within 2.5 min. Plasma ANP concentrations had virtually returned to basal levels (32.7 +/- 2.7 pmol/l) 30 min after this acute volume load. A further infusion of 10 ml polygelene colloidal solution in 2 min produced peak venous pressure rises of 10 cm water and caused a dramatic and significant (P less than 0.001) increase of plasma ANP concentration to a peak of 534.8 +/- 38.5 pmol/l, occurring 7.5 min after infusion. The plasma ANP concentration had fallen but remained above basal levels 30 min later (137.2 +/- 26.4 pmol/l). Similar results were obtained using an identical protocol but with whole rat blood instead of polygelene solution as the volume-expanding agent. Gel column chromatography suggested that the majority of the immunoreactive ANP in rat plasma was of similar molecular size to rat alpha-ANP (1-28). These results support the hypothesis that blood volume expansion is a potent stimulus for the release of ANP into plasma.

Animals↗
PubMed1986

Effect of haemodialysis on plasma concentrations of atrial natriuretic peptide in adult patients with chronic renal failure.

Twenty patients with chronic renal failure were studied before and after haemodialysis. Plasma atrial natriuretic peptide (ANP) concentrations were markedly elevated (P less than 0.01) before dialysis in comparison with healthy control subjects. After haemodialysis the plasma ANP concentration was lower in 19 patients (P less than 0.01) but remained above the normal range in all but three cases. Systolic and diastolic blood pressure and body weight fell during dialysis but none of these changes correlated with the reduction of the plasma ANP concentration. Chromatographic analysis of plasma extracts indicated that alpha-ANP is the predominant circulating molecular form. The increase in concentration of ANP in plasma between dialyses, at a time when many patients are susceptible to sodium and water overload, and its return towards normal after dialysis supports the putative role of ANP as a circulating factor released in response to sodium and water accumulation.

Adolescent↗
PubMed1986

Neuroendocrine tumours of the gut: long-term therapy with the somatostatin analogue SMS 201-995.

Nine patients with metastatic neuroendocrine tumours of the gut were treated for over 100 days with the long-acting octapeptide of somatostatin, SMS 201-995. Two patients had unusually aggressive tumours (neuroendocrine tumours are typically slow-growing) with only modest elevation of tumour secretory products. SMS 201-995 was given in an attempt to slow tumour growth, but tumour size continued to increase. Three patients had glucagonomas and uncontrolled skin rashes, and four patients had VIPomas, which caused uncontrolled watery diarrhoea. SMS 201-995 was given principally to reduce hypersecretion of hormones from their tumours and to relieve symptoms. All the patients experienced rapid relief of their symptoms when SMS 201-995 treatment was introduced, and symptomatic control was maintained throughout treatment except in one patient, who required a supplementary procedure (pancreatic primary tumour embolization). Circulating peptide levels were initially suppressed, but continued suppression did not occur in every case despite good clinical control. It seems likely that SMS 201-995 has beneficial effects on target organs as well as suppressing the release of peptides from tumour tissue. The tumours did not grow during treatment. The analogue was well tolerated, most adverse effects being minor. Somatostatin inhibited insulin release, but in only one patient was there a slight deterioration of glucose tolerance. SMS 201-995 is therefore a useful therapeutic tool in the long-term management of patients with symptoms due to uncontrolled hormone secretion from neuroendocrine tumours.

Adult↗
PubMed1986

The plasma atrial natriuretic peptide response to treatment of acute cardiac failure, spontaneous supraventricular tachycardia and induced re-entrant tachycardia in man.

Patients with acute congestive cardiac failure had elevated plasma concentrations of atrial natriuretic peptide (ANP) which fell towards normal levels with successful diuretic therapy. The plasma ANP concentration was closely correlated with the clinical condition of the patients as assessed by serial clinical measurement of the jugular venous pressure and body weight. Plasma ANP concentrations were also raised in patients with a spontaneous acute onset of supraventricular tachycardia but to a lesser extent in patients with chronic tachycardia. Again, successful treatment with d.c. cardioversion returned plasma ANP concentrations towards normal. Induction of atrioventricular re-entrant tachycardia produced an acute and marked rise in plasma ANP concentrations, which rapidly returned to normal when the sinus rhythm was restored. This acute ANP rise probably mediates the known acute natriuretic effect of paroxysmal tachycardia. All the data are consistent with the hypothesis that atrial distension, whatever the cause, releases ANP into plasma.

Adult↗
PubMed1985

The effect of human atrial natriuretic peptide on urinary sodium and urinary dopamine excretion in man.

Atrial extracts have long been known to produce natriuresis but it is only recently that atrial natriuretic peptide (ANP) itself has been isolated, purified and sequenced. We have now developed a specific radio-immunoassay for ANP and assessed its biological activity by infusing ANP in normal volunteers. Low dose ANP infusion (1.5 pmol/kg per min) produced no haemodynamic or natriuretic effects. High dose ANP infusion (15 pmol/kg per min) produced an increase in plasma immunoreactive ANP levels of 203 +/- 78 pmol/l and caused the urinary sodium excretion to increase from 3.5 +/- 1.6 to 11.0 +/- 7.4 mmol/30 min period (P < 0.05). No haemodynamic effects were seen with this high dose infusion. No changes in urinary dopamine were seen with either ANP infusion. This study shows that ANP is capable of producing a natriuresis in man in the absence of any generalized haemodynamic effects and that ANP may be an important modulator of salt and water balance in man.

Adult↗
PubMed1984

Decrease in airway pressure during high-frequency jet ventilation in infants with respiratory distress syndrome.

Using a crossover study design, we compared a system of high-frequency jet ventilation with appropriate humidification to pressure-limited conventional ventilation in 12 preterm infants with a birth weight of 1.9 +/- 0.6 kg and gestational age of 32 +/- 2 weeks who had severe respiratory distress syndrome. After a control period of conventional ventilation, high-frequency jet ventilation was administered for 1 to 3 hours at a constant rate (250/min) and inspiratory to expiratory time (1:3 or 1:4) in the same fraction of inspired oxygen as during conventional ventilation. Average peak inspiratory pressure decreased from 29 +/- 3 cm H2O during conventional ventilation to 20 +/- 4 cm H2O during high-frequency jet ventilation (P less than 0.001), whereas positive end expiratory pressure was unchanged, resulting in a reduction in mean airway pressure from 14 +/- 3 to 10 +/- 2 cm H2O (P less than 0.001). There was a simultaneous decrease in PaCO2 (39 +/- 4 to 34 +/- 4 mm Hg, P less than 0.01), but PaO2 did not change. These data indicate that short-term high-frequency jet ventilation maintains gas exchange in infants with respiratory distress syndrome despite a lower PIP and Paw, and results in smaller airway pressure swings than during conventional ventilation. Thus, high-frequency jet ventilation may offer hope for reducing barotrauma in this population.

Blood Gas Analysis↗
PubMed1983

Transient ventilatory response to CO2 as a function of sleep state in full-term infants.

The influence of sleep state on the transient (i.e., initial 60 s) and steady-state ventilatory responses to 2% CO2 inhalation was studied in 19 healthy full-term infants. A nasal mask pneumotachometer was used to measure ventilation and end-tidal CO2 partial pressure (PCO2) and enabled abrupt changes in the inspired gas concentration to be made. The magnitude of the change in minute ventilation for both the transient and steady-state responses to CO2 was not statistically different between active (AS) and quiet (QS) sleep. Nonetheless the greater variability in minute ventilation during AS compared with QS continued throughout the period of CO2 inhalation and was associated with a more variable change in ventilation in the individual infants during AS. There was a greater increase in end-tidal PCO2 over the first 60 s during AS (3.3 +/- 0.3 vs. 2.6 +/- 0.2 Torr, in AS and QS, respectively, P less than 0.03). This may indicate a smaller initial increase in alveolar ventilation, relative to CO2 delivery to the lungs, in response to CO2 inhalation during AS. Asynchronous chest wall movements were more common during AS than QS (P less than 0.005) and did not change with CO2. The inconsistent transient ventilatory response to CO2 during AS compared with QS may be important in the behavior of infants to spontaneous episodes of hypercapnia occurring during AS.

Carbon Dioxide↗
PubMed1983

Optimal position for a spinal tap in preterm infants.

Inasmuch as spinal taps in preterm infants are frequently accompanied by clinical deterioration, the optimal position for this procedure was investigated. Three positions were each randomly assigned for five minutes to 17 healthy preterm infants without a spinal tap actually being performed: (1) lateral recumbent with full flexion (flexed position), (2) lateral recumbent with partial neck extension (extended position), and (3) sitting with head support and spine flexion (upright position). Transcutaneous PO2 and PCO2 were monitored in all infants, minute ventilation (VI) in seven, and heart rate and blood pressure in ten infants. Mean transcutaneous PO2 decreased in each of the three positions. This decrease was significantly greater in the flexed (28 +/- 8 mm Hg) as compared with the extended (18 +/- 8 mm Hg, P less than .001) and upright (15 +/- 11 mm Hg, P less than .001) positions. Mean transcutaneous PCO2 increased only in the flexed position (3 +/- 4 mm Hg, P less than .005) and levels were still elevated five minutes after that position had been discontinued. The consistent decrease in transcutaneous PO2 was accompanied by a variable effect of positioning on VI and there were no episodes of airway obstruction or apnea greater than 10 seconds. Heart rate increased in each position whereas blood pressure remained unchanged. These data suggest that although hypoventilation may contribute to the observed decrease in transcutaneous PO2, ventilation/perfusion imbalance appears to be the major mechanism. As spinal taps performed in the widely accepted flexed position carry the greatest risk of potential morbidity, it is recommended that this position be modified with neck extension or that spinal taps be performed in the upright position.

Carbon Dioxide↗
PubMed1976

Outcome following therapeutic abortion.

Psychological outcome of abortion was studied in 102 patients, measuring multiple variables over four time intervals. Five measured affects--anxiety, depression, anger, guilt, and shame-were significantly lower six months after the preabortion period. The following variables describe subgroups of patients with significant variations in patterns of responses as indicated by changes in affects: marital status, personality diagnosis, character of object relations, past psychopathologic factors, relationship to husband or lover, relationship to mother, ambivalence about abortion, religion, and previous parity. A complex multivariate model, based on conflict and conflict resolution, is appropriate to conceptualize, the unwanted pregnancy and abortion experience. Data suggest that women most vulnerable to conflict are those who are single and nulliparous, those with previous history of serious emotional problems, conflictual relationships to lovers, past negative relationships to mother, strong ambivalence toward abortion, or negative religious or cultural attitudes about abortion.

Abortion, Therapeutic↗
PubMedDate not supplied

Radioimmunoassay of alpha rat atrial natriuretic peptide.

Specific antibodies to alpha 1-28 atrial natriuretic peptide have been raised and used for radioimmunoassay of tissue extracts and for light and electron microscopic immunocytochemistry. The radioimmunoassay has been used to quantitate ANP-immunoreactivity in normal rat heart and hypothalamus and immunocytochemistry to demonstrate its localisation in specific tissue structures. Gel chromatography and high pressure liquid chromatography confirm that the majority of ANP-like immunoreactivity in the atria exists as high molecular weight forms. Rat hypothalamus contains immunoreactive ANP; the concentration per gram of tissue being 2-4 thousand fold less than that of the cardiac atria. The supraoptic region of the hypothalamus did not have a significantly different concentration of ANP-like immunoreactivity from the hypothalamic region as a whole. Immunocytochemical staining with ANP antiserum revealed the cardiac ANP-immunoreactivity to be concentrated around the nuclear poles within the cytoplasm of atrial muscle cells. Electron microscopic study of atrial cells stained with the immunogold technique confirmed the localisation of the ANP immunoreactivity to electron-dense secretory granules. The highest density of regional immunoreactive staining was in the subepicardial area, the lowest in the interatrial septum. The finding that the highest quantities of ANP immunoreactivity occur in areas subjected to the greatest distensional forces supports the hypothesis that atrial stretch is a stimulus to the release of this peptide from cells.

Animals↗