COVERT HYPOTHYROIDISM WITH WEIGHT LOSS AND ATRIAL FIBRILLATION

SUMMARY Hypothyroidism may present with weight gain and/or cardiovascular manifestations such as bradycardia or cardiac failure, but has not previously been documented as presenting with atrial fibrillation and weight loss. Our case highlights the importance of thyroid function tests in heart failure and emphasises the importance of regular follow-up after irradiation to the thyroid.     

Detection of myocardial ischemia in vitro by computed tomography

The applicability of CT in the delineation of ischemic myocardium is defined. Twenty-six dogs had their left anterior descending coronary artery occluded, and radiolabeled microspheres were injected into the left atrium to measure myocardial blood flow. From 30 minutes to 7 weeks after coronary occlusion the hearts were excised and scanned in a CT head scanner. An unbiased observer divided selected CT scans slices into normal, abnormal, and borderline areas of attenuation coefficients; these were correlated with blood flow measurements and a progressive decrease in flow from normal to borderline and borderline to abnormal segments was found. As early as 2 hours after coronary arterial occlusion, areas of reduced attenuation coefficient, corresponding to regions of reduced blood flow, were seen. Areas of increased attenuation were seen in regions containing microcalcifications and fibrosis in several longer term experiments. Areas of reduced blood flow were visible immediately after coronary arterial occlusion with intravenous iodinated contrast material (1 ml/kg). CT detection of regions of reduced blood flow defined by radiolabeled microsphere is a promising means of detecting and sizing myocardial infarcts.     

Degranulation and abnormal bactericidal function of granulocytes procured by reversible adhesion to nylon wool

Granylocyte bactericidal capacity, chemotaxis, hexose monophosphate shung activity (before and after phagocytic stimulus), and quantitative nitroblue tetrazolium reduction and enzyme content were examined in cells obtained by filtration leukaphresis (FL) and continuous-flow centrifugation (CFC). A decrease in the bactericidal efficiency of FL- produced cells compared to that of both normal and CFC-procured granulocytes was found; the decrease was 17% with a cell-to-bacteria ratio of 5:1, and 55% with a 1:1 ratio. Moreover, FL-acquired cells were often vacuolated and consistently contained less acid phosphatase and beta-glucuronidase than did normal granulocytes. When normal cells were incubated for 1-2 hr with nylon wool, 30% of the total acid phosphatase and beta-glucuronidase was released, with no evidence of cell death, thus suggesting degranulation. Similar results were obtained with glass, cotton, or polysulfone plastic fibers. Electron microscopic and peroxidase cytochemical studies of the adherence of normal granulocytes to nylon fibers were also carried out. After 30 min of incubation, cell-to-fiber attachment and cellular aggregation had occurred, although the cells per se appeared normal. After 60 and 120 min, other changes became apparent: (1) a decrease in the amount of cytoplasmic granules; (2) large, intracytoplasmic vaculoles; and (3) extracellular peroxidase on fiber surfaces. We conclude that granulocytes obtained by adherence to nylon fibers show both morphological and biochemical evidence of degranulation and diminished bactericidal capacity, and that these abnormalities may be causally related to decreased granulocyte survival in transfusion recipients.     

Greater hypertrophy in right than left ventricles is associated with pulmonary vasculopathy in sinoaortic-denervated Wistar-Kyoto rats

1. Biventricular hypertrophy has been described in a high blood pressure variability (BPV) model of sinoaortic-denervated (SAD) rats without systemic hypertension. To explore the possible involvement of the lung in SAD-induced right ventricular hypertrophy (RVH), we examined lung morphology, in addition to systemic haemodynamics and ventricle morphology, in Wistar-Kyoto rats 32 weeks after SAD. 2. In Wistar-Kyoto rats 32 weeks after SAD, there existed a substantial elevation in BPV, with no change in the average level of arterial pressure. Biventricular hypertrophy following SAD was characterized by a greater hypertrophy in right than left ventricles; both absolute and normalized right ventricular weights were significantly increased by 22 and 27％, respectively, and only normalized left ventricular weight was significantly increased by 12％. No infarcts were found in any ventricles examined. 3. In the lung, the most prominent change following SAD was pulmonary vasculopathy, including wall thickening, perivascular fibrosis and cell infiltration. In pulmonary arteries with an internal diameter of 70-130 microm, the external diameter, wall thickness and wall thickness to internal diameter ratio were increased in SAD compared with control rats. 4. There was no correlation between right and left ventricular weights. In contrast with BPV-correlated left ventricular weight, right ventricular weight was correlated with the wall thickness of the pulmonary artery, but not with BPV. 5. These findings suggest that greater RVH following SAD is associated with pulmonary vasculopathy, but is not secondary to the left ventricular problems or high BPV.