The role of dopamine synthesis in the renal actions of human α-atrial natriuretic peptide (αANP) was investigated in six dehydrated volunteers using the DOPA decarboxylase inhibitor carbidopa.

Coronary arterial reperfusion is commonly associated, in anaesthetized animals, with severe arrhythmias, but the clinical relevance of this model remains uncertain. Continuous electrocardiographic ST-segment recording was performed immediately from admission in 38 patients who presented within six (mean 2.5) hours of the onset of acute myocardial infarction and had emergency coronary arteriography and thrombolysis with intracoronary streptokinase. All patients received high doses of isosorbide dinitrate but no prophylactic anti-arrhythmic drugs. In 19 patients, 36 occurrences of intermittent reperfusion were observed. Stable reperfusion was achieved in 32 patients. Only 14 episodes of arrhythmia (11 ventricular) were observed in 6 patients within five minutes of transient or stable reperfusion. No episodes of arrhythmia were documented within five minutes of the other 57 occurrences of reperfusion. In contrast, 215 episodes of arrhythmia (198 ventricular) not associated with reperfusion were recorded in 32 patients. Arrhythmias are commonly observed in patients during evolving acute myocardial infarction and thrombolysis but are an insensitive and rarely specific marker of reperfusion at the time when this occurs.

Thirty-three acromegalic patients were treated with radiotherapy and followed up for at least 3 years (mean 6 years, range 3 to 12). Seventeen had not had previous pituitary ablative therapy and 16 had. The mean GH level for these two groups before radiotherapy was comparable at 98 and 119 mIU/l. The observed frequency of reaching less than 10 mIU/l was 53% and 75% of patients in the two groups, respectively, the mean observed falls in growth hormone level were 81 and 85% of the initial level, and the calculated exponential decline rate of GH level was 72 and 52% per year. Considering all 35 patients, requirement for pituitary hormone replacement therapy increased from 15 patients before radiotherapy to 20 after radiotherapy, being mostly those who had had prior ablative therapies. There were no complications attributable to the radiotherapy treatment. It appears that radiotherapy is equally efficacious whether a prior unsuccessful ablative procedure had been used or not.

Twenty two boys with Duchenne muscular dystrophy were entered into a randomised double blind crossover trial to compare respiratory muscle training with a Triflow II inspirometer and 'placebo' training with a mini peak flow meter. Supine posture was associated with significantly impaired lung function, but respiratory muscle training showed no benefit.

Desmosine has been quantitated in the normally grown fetal and early infant lung by radioimmunoassay. Desmosine could first be detected at 22 weeks gestation: the concentration of desmosine expressed per milligram lung DNA increased in approximately linear form up to about 55 weeks postconceptional age. The concentration in peripheral lung was approximately half that in whole lung homogenates. Lungs of infants dying with acute HMD and lungs of growth retarded infants showed no significant differences from the normals, although there was a tendency for higher desmosine concentrations in prematurely born growth retarded infants.

Vibration perception threshold was measured with a biothesiometer by a single observer at both medial malleoli and both big toes in 110 diabetic patients aged 15-65 selected at random and in 64 non-diabetic subjects aged 20-65. The vibration perception threshold showed appreciable individual variation both between contralateral sites and between ipsilateral sites, differing by at least 30% between the big toes in 26 (24%) of the diabetic patients and 16 (25%) of the non-diabetic group. Variability between sites was significantly greater in the diabetics than the normal subjects. The vibration perception threshold exceeded published normal values at one or more sites in 22 of the diabetic patients but at all four sites in only four. The wide variability in vibration perception threshold among sites may be due to the tissue characteristics locally and, in diabetic patients, possibly to asymmetric neuropathy. Biothesiometer readings at single or unilateral sites may be unrepresentative or misleading.

Six normal male subjects, ages 28-40 years, were studied on separate days during increasing infusions with adenosine, 40-120 micrograms kg-1 min-1, before and during infusions of two xanthine derivatives, theophylline (mean plasma concentration 9 mg l-1) and enprofylline (mean plasma concentration 3 mg l-1). The study was double-blind, randomized, placebo controlled. Cardio-respiratory variables were measured non-invasively. Adenosine by itself increased heart rate (P less than 0.05), skin temperature (P less than 0.05), resting minute ventilation (P less than 0.01) and decreased estimated Pa, CO2 (P less than 0.01). Compared with placebo enprofylline increased heart rate (P less than 0.05) and shifted the heart rate and ventilation dose-response curves of adenosine upwards (P less than 0.05 and P less than 0.02, respectively). Theophylline did not by itself affect heart rate but significantly (P less than 0.05) reduced the heart rate response to adenosine. Compared with placebo theophylline caused a small increase in minute ventilation (P less than 0.05) and flattened the dose-response curves of the effects of adenosine on ventilation (P less than 0.01) and Pa, CO2 (P less than 0.01). Theophylline also reduced abdominal and chest discomfort caused by adenosine permitting significantly (P less than 0.05) higher infusion rates of adenosine. These findings suggest that, with equipotent bronchodilating plasma concentrations, theophylline can inhibit while enprofylline augments some cardio-respiratory stimulant effects of infused adenosine in man.

The effects of preterm birth and mechanical ventilation on growth of the alveolar region of the lung were assessed by morphometric and/or quantitative biochemical methods in the lungs from 104 perinatal and infant autopsies. The lungs of 4 preterm infants who died at 4–16 weeks age without having received mechanical ventilation were large relative to body weight but showed normal alveolar number and alveolar surface area. Infants treated by mechanical ventilation for hyaline membrane disease (HMD) and who died at ages from 1 week up to 14 months showed impairment in alveolar development evidenced by low alveolar number and a low alveolar surface area. Lung volume and total lung DNA values were relatively normal. Dilated alveolar ducts were a feature at all ages with emphysematous changes apparent in the longest surviving infants. Biochemical features included a high concentration of hydroxyproline, reflecting collagen, and a high desmosine concentration, reflecting elastin, in infants dying at less than 60 weeks postconceptional age. Changes in the lungs of infants ventilated at low pressures for conditions other than HMD were of a similar nature but less severe than those seen in the HMD group. These findings indicate that preterm birth alone may have little adverse influence on lung development but that conditions necessitating mechanical ventilation may lead to permanent impairment in alveolar development. We postulate that the standard technique of applying positive pressure ventilation may itself lead to impaired alveolar growth, although the effect is enhanced by concomitant HMD and BPD.

Weight, DNA, protein, hydroxyproline and disaturated phosphatidylcholine (DSPC) content were investigated in lungs of 97 normally formed infants over an age range from 22 to 75 postconceptional weeks, including 25 cases of hyaline membrane disease (HMD) and 13 small-for-dates infants (SFD). Lung weight and lung DNA relative to body weight were markedly lower in infants who died at 37–41 weeks than in those who died at shorter gestations or in early infancy. Total lung DSPC and DSPC concentration had a narrow peak at 36–41 weeks. The DSPC concentration per milligram of lung DNA in the first few months of infant life was similar to that in infants at 24 weeks gestation. Lung protein concentrations increased steadily but were variable at all ages. SFD infants had significantly higher concentrations of hydroxyproline and showed a peak DSPC concentration at an earlier gestation than the normals. Lungs of HMD infants showed some increase in hydroxyproline concentration but little other quantitative evidence of difference from the normals.

We have compared the acute ventilatory changes during induction of anaesthesia with equipotent doses of thiopentone and propofol in 12 premedicated female patients. Using ventilatory inductance plethysmography we have shown that both agents depress respiration to a similar and significant degree (P less than 0.001). However, although the functional residual capacity was reduced in patients receiving propofol, it increased slightly after induction with thiopentone (P less than 0.05).