Search

A 67 year old woman with a permanent pacemaker was admitted with pulmonary oedema and mitral valve incompetence two months after a myocardial infarction. Echocardiograms showed good left ventricular function and a large coil of apparent thrombus in the right atrium prolapsing into the right ventricle. Intermittent loss of pacemaker sensing and capture was noticed on admission and probably caused the supraventricular tachycardia and ventricular fibrillation that occurred before an exploratory bypass operation. At operation rupture of the papillary muscle was found and the mitral valve was replaced. A large piece of thrombus was retrieved from the right pulmonary artery. The right heart contained no clot and the pacemaker wire was not displaced. It is envisaged that the strand of venous thrombus was caught in the permanent pacing wire at the tricuspid valve level resulting in an unusual case of pacemaker malfunction. The eventual poor outcome was almost certainly influenced by the arrhythmias and pulmonary embolism caused by the clot and might have been avoided by early operation.

The effect of bilateral adrenalectomy at 120 d gestation on subsequent maturation of proximal and distal small intestine was investigated in chronically catheterized fetal sheep. Ten adrenalectomized and fourteen controls were examined at 136 d; some following infusion of [3H]thymidine at 3-6 d or 4 h before termination of pregnancy. Mean plasma cortisol levels were 5.3 +/- 0.7 ng/ml in the adrenalectomized group; control values ranged from 14 to 39 ng/ml level during the 2-week experimental period. Fetal body growth was significantly increased following adrenalectomy. In the small intestine, growth of mucosal structures was reduced, especially in distal regions. Villus height was significantly reduced in both regions. External muscle thickness was significantly increased in both regions. Despite these changes there was no alteration in villus enterocyte morphology, nor were there any significant changes in villus or crypt densities. The proportion of crypt cells labelled with [3H]thymidine was unaffected by adrenalectomy. In proximal regions, migration rate of labelled enterocytes declined from 12.0 to 5.83% villus height/d (P less than 0.025) after adrenalectomy; there was no change in migration rate in distal regions. The estimated renewal time was greater in both proximal and distal regions in adrenalectomized compared with control fetuses.

Light microscope peroxidase-antiperoxidase immunohistochemistry has been applied to the pituitary of adult and fetal sheep from 40 to 145 days of gestation. In the adult, immunoreactive ACTH cells were darkly stained and angular with cytoplasmic processes surrounding neighbouring unstained cells. In the fetus, cells which stained for ACTH were observed in the pars distalis at 40 days. From approximately 90 days, two morphologically distinct ACTH-positive cell types were clearly discernible. The predominant type was large and variably stained. These cells usually occurred in clusters and were often arranged in palisades. The other type resembled ACTH-positive cells in the adult. After 130 days the population of large cells declined and completely disappeared before term in most fetuses. The pars intermedia showed a different pattern of staining. In the fetus, ACTH-positive cells were observed in this region after 60 days gestation and by 90 days almost all the pars intermedia cells were strongly stained. By contrast, the cells in the adult pars intermedia were only lightly stained.

In order to evaluate the potential of balloon occlusion during coronary angioplasty as a model of myocardial ischaemia in man we have measured coronary sinus blood flow (CSBF), myocardial oxygen consumption (MVO2), lactate extraction (LER) and electrocardiographic changes in 11 patients undergoing left anterior descending artery (LAD) angioplasty. Baseline measurements were made before balloon crossing and between inflations. Four consecutive inflations each of 60 s duration were made; 5 min return to baseline was allowed between inflations. There was a significant reduction in CSBF and MVO2 (ml min-1) during inflations 2, 3 and 4 (CSBF: 121 +/- 66----94 +/- 53, 113 +/- 49----99 +/- 42, 124 +/- 66----102 +/- 41, P less than 0.02; MVO2: 11.3 +/- 6.6-9.1 +/- 3.9, 10.4 +/- 3.7-8.7 +/- 2.4, 12.2 +/- 4.4----9.4 +/- 2.8, P less than 0.05). However during the first period of balloon occlusion there were inconsistent changes in coronary flow with an overall rise in mean flow (97 +/- 35----128 +/- 80 ml min-1, P = NS) and an overall rise in mean myocardial oxygen consumption (9.6 +/- 3.8----12.5 +/- 7.5 ml min-1, P = NS). There was lactate production during all four inflations but the changes during the first one did not achieve statistical significance. These inconsistent changes during the first inflation were thought to be due to partial obstruction of the stenosis by the deflated balloon before primary dilatation. The changes due to crossing and during the first two inflations were further investigated in another group of 12 patients undergoing LAD angioplasty. Great cardiac vein flow (GCVF), CSBF, MVO2 and LER were recorded at baseline, during crossing and during the first two inflations. With the deflated balloon across the stenosis there were no changes in CSBF or MVO2 but there was a fall in GCVF (103 +/- 28----77 +/- 50, P = NS) and a significant fall in LER (77 +/- 57----16 +/- 37, P less than 0.01). Although there was a fall during the first inflation in CSBF, GCVF, MVO2 and lactate extraction none of these changes were significant. During the second inflation these changes were of greater magnitude and achieved statistical significance. While balloon occlusion during coronary angioplasty has the potential of providing a model of ischaemia in man we have found the first inflation period unreliable, due to the variable degree of occlusion by the deflated balloon. We suggest that only subsequent inflations after the primary dilatation are used for observations.(ABSTRACT TRUNCATED AT 400 WORDS)

The recurrence of angina soon after myocardial infarction is not uncommon and represents areas of viable myocardium at risk from infarct extension and thus a worse prognosis. A better understanding of the pathogenesis of acute ischaemic syndromes and developments in interventional cardiology in the past decade have helped us rationalize our approach to this high-risk subset and achieve maximal myocardial salvage with its short- and long-term benefits.

As part of a nutritional status survey of 691 non-institutionalized men and women aged 60 years and older, supplement use was reported by 45% of the males and 55% of the females. Supplement use was more prevalent in females than males at each age decade. Vitamins C and E were the most commonly used supplements. Mean dietary nutrient intakes were calculated from a 3-day food diary. The percentage of dietary intakes falling below 2/3 1980 Recommended Dietary Allowance (RDA) was comparable for users and non-users of supplements. Use of supplements markedly decreased the proportion of subjects with inadequate nutrient intake (using a 2/3 RDA criterion), particularly for vitamins B6, B12, and D, folic acid, and calcium. However, for both males and females, potentially excessive intake levels (10 times the RDA) of thiamin, vitamin A, and vitamin E supplementation were observed.

Light microscopy of coronal sections of the sheep pars intermedia revealed a compact, incompletely lobulated V-shaped region about 15-20 cells thick, situated between the pars distalis and the pars nervosa. A prominent hypophysial cleft and follicles containing a colloid-like substance were seen. Using electron microscopy, five cell types could be distinguished: pars intermedia glandular cells, pars distalis-like glandular cells, interstitial cells, follicular cells and cleft lining cells. The polyhedral to pear-shaped pars intermedia glandular cells predominated. They contained dense-cored, membrane-bound granules near the Golgi complex, and larger, irregular vesicles with finely granular contents of varying electron density throughout the remaining cytoplasm; exocytotic release of granules was occasionally observed. Smaller numbers of cells resembling those seen in the pars distalis were scattered throughout the pars intermedia. Interstitial cells usually possessed elongated cytoplasmic processes which extended between the glandular cells, and were characterized by deeply indented nuclei, elaborate junctional complexes and an absence of cytoplasmic granules. Cells lining the follicles resembled the interstitial cells. The major cells bordering the hypophysial cleft were triangular in section and bore irregular microvilli on their free surface. The pars intermedia appeared to be less vascular than the remainder of the hypophysis and only occasional fenestrated capillaries were seen. Nerve profiles were rare.

The primary success rate and incidence of major complications have been retrospectively assessed in a consecutive series of 224 patients undergoing percutaneous transluminal coronary angioplasty (PTCA) in one centre. The patients have been divided into three groups; those with angina and no previous myocardial infarction (Group 1; N = 130), those with angina and a previous transmural myocardial infarction (TMI) (Group 2; N = 59), and those with angina and a previous non-transmural myocardial infarction (NTMI) (Group 3; N = 26). The three groups were well matched for age, gender and angiographic severity of stenosis. The primary success rate in Group 1 was 90% compared to 64% in Group 2. The success rate in Group 3 lay in between at 77%. The lower success rates in Groups 2 and 3 were mainly due to an increase in the frequency of major complications. Acute coronary occlusion occurred in seven patients in Group 1, nine patients in Group 2 and four patients in Group 3. In all these patients in Groups 2 and 3 the outcome of acute occlusion was a procedure-related clinical myocardial infarction despite immediate re-angioplasty and/or emergency coronary artery bypass grafting whereas only four patients in Group 1 sustained an acute infarct. In this series of patients undergoing coronary angioplasty for symptom limiting angina, previous myocardial infarction appears to be a risk factor for a lower success rate mainly due to an increase in the frequency and severity of major complications.