PLASMA VASOPRESSIN AND ATRIAL NATRIURETIC FACTOR DURING HAEMORRHAGE: INFLUENCE OF CARDIAC AND AORTIC RECEPTORS

1. The changes in plasma concentrations of immunoreactive vasopressin (iVP) and atrial natriuretic factor (iANF) in response to haemorrhage (10-30% blood volume) were measured in 10 anaesthetized rabbits before and after cardiac receptor denervation (vagal nerve section). Carotid sinus pressure was maintained constant (60 mmHg) to eliminate any changing input from carotid baroreceptors. 2. Haemorrhage increased iVP before and after vagal nerve section indicating that withdrawal of input from aortic baroreceptors may have contributed to the increase in iVP. 3. Section of the vagus nerves attenuated the iVP response to haemorrhage. 4. There was no correlation between release of iVP and iANF. 5. Haemorrhage decreased iAF before and after vagal nerve section. Section of the vagus nerves increased iANF. Plasma iANF was highly correlated with atrial pressure and mean arterial pressure suggesting iANF release was secondary to changes in cardiac haemodynamics.     

Staphylococcus epidermidis as a cause of postoperative wound infection after cardiac surgery: assessment of pathogenicity by a wound-scoring method

Wound infection after clean surgery prolongs hospital stay but the organism most commonly isolated from wound discharge, Staphylococcus epidermidis, is often dismissed as a contaminant or commensal. The wounds of 517 patients were assessed, after cardiac surgery, by a wound-scoring method ('ASEPSIS') and a close comparison was made of the appearance and clinical outcome of 89 wounds, from which bacteria were isolated. There was no significant difference in the scores of 49 wounds, where S. epidermidis was the sole isolate (9.5 per cent of all wounds, 95 per cent CI 6.9-12.0 per cent), and 13 wounds infected with Staphylococcus aureus (2.5 per cent, 95 per cent CI 1.2-3.9 per cent). Repeat cultures were obtained from 21 of the 49 wounds and, in 16 of these, the second isolate showed the same biochemical reactions and antibiotic resistance pattern as the first. Infection of sternal wounds is commoner with coagulase-negative staphylococci than with S. aureus and, clinically, is just as severe.     

Acute diverticulitis: safety and value of contrast studies in predicting need for operation

Results of treatment of 70 patients hospitalized with acute diverticulitis were analysed to determine the value of early contrast enema in management. A water-soluble enema done during the first week of hospitalization in 48 patients showed diverticulosis with spasm (30), a leak or peridiverticulitis (16) and a normal study (two). No complications were caused by the study. Forty patients improved on medical therapy, but four relapsed after discharge. Thirty-four (49%) patients had urgent operation during hospitalization for the acute episode of diverticulitis. Findings on contrast enema correlated with the need for surgery during the acute phase: 13 of 16 with peridiverticulitis or a leak compared with three of 30 with diverticulosis/spasm (P less than 0.001). Operations performed were: sigmoid resection and primary anastomosis (17) with covering colostomy (five). Hartmann's operation (eight), colostomy and/or drainage (seven), right hemicolectomy (two). Findings at surgery were: abscess (15), phlegmon (12), peritonitis (five) and colovesical fistula (two). It is concluded that early contrast enemas of the distal colon done with appropriate precautions are useful in confirming the diagnosis of diverticular disease: only two of 48 studies were falsely negative. A pericolic extravasation (as opposed to a small sinus tract) or abscess usually indicates need for operation, whereas the finding of diverticulosis/spasm suggests a favourable outcome of conservative management.     

Estimating cardiovascular disease risk and the metabolic syndrome: a Framingham view.

The metabolic syndrome as currently defined by the Adult Treatment Panel III includes multiple components. This article describes the background for these components' inclusion in the syndrome,measurement of these factors, and the appropriate interventions.The factors are highly interrelated and the true utility of this diagnostic entity is under critical evaluation as new and existing data are evaluated concerning the role of the syndrome in the development of vascular disease and other clinical outcomes.     

On the dual structure of the auditory brainstem response in dogs.

OBJECTIVE: To use the over-complete discrete wavelet transform (OCDWT) to further examine the dual structure of auditory brainstem response (ABR) in the dog. METHODS: ABR waveforms recorded from 20 adult dogs at supra-threshold (90 and 70dBnHL) and threshold (0-15dBSL) levels were decomposed using a six level OCDWT and reconstructed at individual scales (frequency ranges) A6 (0-391Hz), D6 (391-781Hz), and D5 (781-1563Hz). RESULTS: At supra-threshold stimulus levels, the A6 scale (0-391Hz) showed a large amplitude waveform with its prominent wave corresponding in latency with ABR waves II/III; the D6 scale (391-781Hz) showed a small amplitude waveform with its first four waves corresponding in latency to ABR waves I, II/III, V, and VI; and the D5 scale (781-1563Hz) showed a large amplitude, multiple peaked waveform with its first six waves corresponding in latency to ABR waves I, II, III, IV, V, and VI. At threshold stimulus levels (0-15dBSL), the A6 scale (0-391Hz) continued to show a relatively large amplitude waveform, but both the D6 and D5 scales (391-781 and 781-1563Hz, respectively) now showed relatively small amplitude waveforms. CONCLUSIONS: A dual structure exists within the ABR of the dog, but its relative structure changes with stimulus level. SIGNIFICANCE: The ABR in the dog differs from that in the human both in the relative contributions made by its different frequency components, and the way these components change with stimulus level.