Biomedical subjects
Publications and source records attributed to G Buzzigoli.
We report the case of a woman with severe hypothyroidism and without concomitant myocardial damage, in whom elevated CK-MB values were measured by radioimmunological and enzymatic methods before and after thyroid replacement therapy. The patient's CK-MB activity was shown to be actually due to an atypical CK band between CK-MM and CK-MB (also termed "macro CK" or "idiopathic serum CK-BB").
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The cardiovascular effects of dilazep, a new antianginal drug, were investigated in 18 patients, who underwent cardiac catheterization and coronary angiography for the evaluation of chest pain. Dilazep, 0.2 mg/kg, was injected intravenously over 1 to 2 minutes. The changes induced by dilazep in coronary tone were assessed by quantitative angiography in four patients, changes in systemic and coronary hemodynamics and blood gases in eight patients, and changes in systemic and pulmonary hemodynamics and blood gases in six. In 6 of the 18 patients the effects on hemoglobin-O2 oxygen binding were also investigated. Following dilazep administration, we observed a marked reduction of coronary resistance (six patients) (0.5 vs 1.0 mm Hg X min X ml-1, p less than 0.01) and of aortic-coronary sinus oxygen difference (seven patients) (4.6 vs 12.3 vol%, p less than 0.01), and a 23% increase in coronary diameter (four patients) (p less than 0.001). Total systemic resistance was also reduced by dilazep (six patients). Conversely, only minimal or insignificant changes were observed in heart rate (14 patients), aortic pressure (14 patients), total pulmonary resistance (six patients), myocardial oxygen consumption (six patients), double product (14 patients), blood gases (seven patients), and hemoglobin-oxygen affinity (six patients). We conclude that dilazep exerts a powerful dilating action on coronary vasculature without appreciable increase of myocardial oxygen consumption and cardiac work simultaneously with a reduction of peripheral resistance.
An accurate and close follow-up of serum levels of thyroid hormones and various muscle markers (myoglobin, creatine kinase and its isoenzymes CK-MB and CK-BB, lactic dehydrogenase, alpha-hydroxybutyric dehydrogenase, etc.) was carried out in 10 hypothyroid patients on replacement therapy. The main muscle markers, creatine kinase and myoglobin, were elevated respectively in 9 and 6 subjects. In 1 male significant CK-MB traces were measured, while in 1 woman significant CK-BB amounts were assayed. Significant correlations between patients' thyroid hormones and the levels of the muscle parameters were found. The rate of normalization of thyroid hormones and muscle markers in relation to replacement therapy was also studied. Myoglobin and creatine kinase have proved to be the best indicators of the hypothyroid myopathy, since they are sensitive for the early detection of muscle involvement due to the metabolic disorder and are closely correlated to the metabolic conditions of patients.
The acute effects of hemodialysis on the serum inorganic phosphorus levels (sPi) with relation to the predialysis plasma volume (PV) and the hematocrit (Ht) values were studied in a group of chronic uremic patients on regular hemodialysis. The results obtained confirmed the close direct correlation between predialysis sPi and fall in sPi induced by hemodialysis. Furthermore, the present fall in sPi induced by hemodialysis was found to be directly correlated to the PV values, and inversely to the HT values. An equation was derived from these data to predict in the individual patients the postdialysis sPi levels, utilizing both the predialysis sPi and the Ht values; this equation showed a better predictive capability than similar expression based on the use of the predialysis sPi value alone.
Glucose was measured by the ferricyanide, the Beckman glucose oxidase, and the hexokinase procedures in 228 plasma samples taken during standard oral glucose-tolerance tests in 17 normal subjects and in 21 chemical diabetics. The neocuproine method was also used to measure glucose concentration in 156 samples (78 before and 78 after dialysis) collected from six diabetic and uremic patients who were on maintenance hemodialysis. Ferricyanide in all conditions and neocuproine in uremic patients overestimated glucose concentrations over the entire experimental range as compared with either enzymic method. This bias or systematic error of the reducing vs the enzymic procedures, due to nonglucose reducing substances ("saccharoids"), becomes considerably greater when their concentration is increased as in chronic uremia. Also, the inverse relation between glucose concentration and overestimation of glucose by the reducing methods has been detected. With respect to the hexokinase method, a mild but significant underestimate of glucose oxidase readings has been observed for higher glucose concentrations. We find neocuproine to be the most imprecise of these procedures.
The Mg, Ca and immunoreactive parathyroid hormone (PTH) serum levels were determined in 22 uremic patients on chronic hemodialysis with different Mg concentrations in the dialysate. Baseline levels of PTH, Ca and Mg were obtained over a 4-month-period whilst on Mg dialysis of 1.5 mEq/l. Patients were then divided into three groups: 10 patients were dialyzed for 6 months with 0.5 mEq/l of Mg, 7 patients with 1.5 mEq/l, and 5 patients wih 2.5 mEq/l Mg. At the end of the 6-month period with differentiated Mg dialysis the three groups were characterized by significantly different Mg serum levels. On the contrary, no significant changes were observed in the PTH or the Ca serum levels. The results of this study indicate that PTH secretion in uremic patients on regular hemodialysis is not appreciably influenced by the Mg serum levels.
The correlation between whole blood potassium (K) concentration and hematocrit (Ht) was investigated in chronically dialyzed uremics with a broad range of Ht. This correlation was found to be represented by a curve and its form was derived by the manipulation of the formula concerning the inverse relationship between erythrocyte K concentration and Ht. These findings show that in dialyzed patients the whole blood K concentration can be correctly predicted from any Ht value, despite their wide range of plasma K concentration.
The determination of whole blood magnesium concentration (MgT) was investigated in uremics on chronic dialysis with a broad range of hematocrit (Ht) and of plasma magnesium concentration (MgP). In view of the inverse correlation between erythrocyte magnesium concentration (MgC) and Ht in dialyzed uremics, as shown in our previous paper, it was possible to derive a formula which expressed MgT in terms of MgP and Ht. By exploring the predictive power of this formula, it can be concluded that MgT can be calculated directly from MgP and Ht.
A hereditary defect in the outward ouabain-resistant, furosemide-sensitive (ORFS) Na+/K+ cotransport has recently been reported by Garay and Meyer in erythrocytes of essential hypertensive patients and some of their normotensive offsprings. Since Na+/K+ cotransport in erythrocytes operates bidirectionally, the same defect might be detectable in the ORFS component of K+ influx rate. To test this hypothesis outward and inward Na+/K+ cotransport measurements were performed in erythrocytes of hypertensives and normotensive controls. Our preliminary results confirm the observation of a reduced outward cotransport in essential hypertension and also suggest that inward cotransport may be reduced in essential hypertension.
Plasma and erythrocyte potassium (K) concentrations were measured in uremics of chronic dialysis and in a control group composed of healthy persons and of patients with anemia due to causes other than renal failure. The behavior of the erythrocyte K content in uremics did not differ from that of the control group and in both cases a close inverse relationship was present between hematocrit and erythrocyte K concentration, irrespective of its plasma level. These findings suggest that the red blood cell count, rather than renal failure, may affect the erythrocyte K content.
The correlation between whole blood potassium concentration (Kt) and hematocrit (Ht) was investigated in subjects with a broad range ofHt. This relationship was found to be represented by a curve, and its form was derived by the manipulation of the formula concerning the inverse correlation between Ht and erythrocyte potassium concentration (Kc).
The serum levels of PTH, Mg, Ca, inorganic phosphate (Pi) and alkaline phosphatases (AlkPase) were determined in 22 uraemic patients on chronic haemodialysis with different Mg levels in th dialysate, in an attempt to clarify the pathogenesis of uraemic osteodystrophy. Baseline levels of all the considered parameters were obtained over a four month period whilst on standard Mg concentration in the dialysis solution (1.5 mEq/L). Patients were then divided into three groups: 10 patients were dialysed for six months with 0.5mEq/L of Mg, seven patients with 1.5mEq/L and five patients with 2.5mEq/L in the dialysate. At the end of the six months with differentiated Mg dialysis, the three groups had significantly different Mg serum levels, whereas no significant changes were observed in the PTH and Ca serum levels. All the patients on high-Mg dialysis showed a significant reduction of the Pi serum levels, whereas a significant increase of AlkPase was observed in the low-Mg dialysis group. The overall results obtained in the present study indicate a possible beneficial effect of low-Mg dialysis on the progression of uraemic osteodystrophy of patients on maintenance haemodialysis.
We measured glucose concentrations with the Beckman Glucose Analyzer, before and after storage at -20 degrees C for various intervals, in 228 plasma samples from oral glucose tolerance tests on 17 normal subjects and 21 patients with impaired carbohydrate tolerance, and also in 82 control samples collected daily, after overnight fast, from seven insulin-dependent diabetics. We found a significantly (p < 0.001) positive relation between storage interval and percentage decrease in glucose concentration. Evidently, the longer plasma is stored, the greater the decrease in glucose.
Plasma and erythrocyte magnesium (Mg) concentrations were measured in uremics on regular hemodialysis, in healthy persons and in patients with anemia due to causes other than renal failure. The mean plasma Mg concentration was found to be significantly higher in the uremic patients than in other subjects. The erythrocyte Mg concentration in anemic uremics and in nonuremic anemics was found to be higher than in normal subjects and a close inverse relationship was found between this figure and the hematocrit. It seems reasonable to argue that anemia, rather than renal failure, is related to the high concentration of Mg in erythrocytes.
A study was carried out to evaluate the effectiveness of glipizide in insulin-dependent diabetic patients. An intravenous glipizide (2 mg) test was carried out in 7 patients before and after a period of associated insulin-glipizide treatment (mean daily dose of 80.7 i.v. lente insulin and 14.3 mg glipizide for 9.1 months) to assess the capacity of the sulphonylurea to reduce acutely the plasma glucose and lactate levels. Glipizide did not produce glucose variations in either test but did result in a significant decrease, in the first test only, in mean plasma baseline levels of lactate, which were higher than normal in these patients. There was no reduction in daily insulin requirements after the period of associated glipizide-insulin treatment. It is concluded that, in the dosage used, intravenous glipizide probably has no hypoglycaemic effects in insulin-dependent diabetics. Moreover, it did not prove useful in combination with insulin. However, the reduction in plasma lactate may be related to an acute enhancement of the exogenously administered insulin. This improvement in the insulin effect may be an acute one among the so called "extra-pancreatic" actions which have been demonstrated for glipizide and other sulphonylureas.
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