A molecular genetic approach to the study of catecholamines.
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Biomedical subjects
Publications and source records attributed to C Boni.
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The clinical recognition of perioperative myocardial necrosis represents one of the clue factors in the management of cardiac surgical patients (pts). This study was performed to determine whether there is any relationship between reperfusion ventricular fibrillation and/or ST-segment elevation and postoperative enzymatic release. Serum enzyme levels and ECG were monitored during and after cardiac operations in 23 pts (15 for valvular replacement and 8 for aortocoronary bypass graft). After aortic unclamping only 6 pts showed stable rhythm. Of the 17 pts who developed ventricular fibrillation 10 showed ST-segment elevation (83% of the 12 pts with ST-segment elevation). Although no significant difference was observed, pts with ST-segment elevation showed higher average enzyme (CK, CKMB) levels. Pts who had valvular replacement showed significantly higher serum CK and CKMB levels. Of the 4 pts who showed a second enzymatic peak, one died and another one presented complex ventricular arrhythmias. No correlation was observed between electrocardiographic data and post-operative enzymatic release. New theories concerning oxygen free radical generation during and after cardiopulmonary by-pass, with the related therapeutic perspectives, are discussed.
Tyrosine hydroxylase is the rate-limiting enzyme in catecholamine synthesis; the gene has previously been cloned and localised to the short arm of chromosome 11. Because of the interest in tyrosine hydroxylase as a candidate gene for manic-depressive psychosis and other affective disorders, we carried out family studies to determine the linkage of tyrosine hydroxylase with insulin, beta-globin, D11S12 and Harvey-ras 1, members of a linkage group which has previously been localised to 11p. Using DNA from the Centre d'Etude du Polymorphisme Humain (CEPH) and from two large British pedigrees, we show that tyrosine hydroxylase is closely linked to these four loci (z = 7.36, theta = 0.04 for linkage to insulin) and suggest a gene order based on multipoint mapping.
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").
Using a panel of human-mouse somatic cell hydrids and a cDNA probe for human tyrosine hydroxylase, we have assigned the structural gene for tyrosine hydroxylase to chromosome 11 by Southern blotting techniques.
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.
Individual cloned HindIII fragments of vaccinia virus DNA were introduced into cells by DNA-mediated gene transfer. The presence of individual fragments in the different transformants was confirmed by Southern blot hybridization analysis. Several of the transformants were found to express viral sequences at various levels. The sizes of the transcripts containing vaccinia virus sequences were highly heterogeneous, with no discrete species of RNA. Positive clones contained vaccinia virus sequences in both the poly(A)+ and poly(A)- RNA fractions, although the prevalence of these sequences was variable in the two fractions. The S1 nuclease map of the 5' end of the transcripts from transformants containing the HindIII-J fragment revealed a unique 5' end, similar to RNA from virus-infected cells. In contrast, analysis of the 3' end of RNAs from these transformants showed a high degree of heterogeneity, which might explain the heterogeneity found in Northern blot patterns. In this report, it is shown for the first time that in cells transformed with vaccinia virus DNA there is proper initiation for, at least, the viral thymidine kinase gene.
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.
One hundred-forty-five postmenopausal women with metastatic breast cancer entered a prospective randomized trial comparing treatment A (cyclophosphamide, methotrexate, and 5-fluorouracil; CMF) with treatment B (the same chemotherapy plus tamoxifen; CMF plus T). Patients on treatment A had T added to CMF at the time of progression or relapse (second-line CMF plus T). One hundred thirty-three cases were evaluable. Considering response rate to first-line treatment, CMF plus T appeared to be significantly superior to CMF alone (74 versus 51%, respectively; P less than 0.01). Median time to failure to first-line treatments, considering all patients, was longer in CMF plus T than in CMF arm (48 and 24 weeks, respectively; P = 0.06). Considering patients showing objective remission, median duration of response to CMF was similar to that of CMF plus T (47 and 51 weeks, respectively). Twelve of 39 evaluable women treated with second-line CMF plus T showed objective responses (31%). Median time to failure to treatment procedures scheduled in arm A (CMF leads to CMF + T) was longer than that to treatment in arm B (CMF plus T) (56 and 48 weeks, respectively; P = 0.08). Median survival was longer in patients randomized to treatment A (111 weeks) than in patients randomized to treatment B (78 weeks), but this difference was not statistically significant (P = 0.25). It can be concluded from this study that a combination of endocrine therapy and chemotherapy is significantly more active than chemotherapy alone in inducing an objective remission. This strategy of treatment is advisable in situations urgently requiring a clinical response. However, as a sequence of chemical and endocrine therapy induced a longer time to development of progressive disease and a better survival, sequential therapy is advisable for common clinical use.
A patient who had received irradiation for inoperable invasive thymoma was treated with cis-platinum after mediastinal and endothoracic recurrence two years from diagnosis. A quick and long-lasting response was observed, which is still present. Systematic phase II trials with cis-platinum in invasive thymoma are suggested.
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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.
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.
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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Catecholaminergic systems in discrete regions of the brain are thought to be important in affective psychoses, learning and memory, reinforcement and sleep-wake cycle regulation. Tyrosine hydroxylase (TH) is the first enzyme in the pathway of catecholamine synthesis. Its importance is reflected in the diversity of the mechanisms that have been described which control its activity; TH levels vary both during development and as a function of the activity of the nervous system. Recently, we deduced the complete amino-acid sequence of rat TH from a complementary DNA clone encoding a functional enzyme. Here we demonstrate that, in man, TH molecules are encoded by at least three distinct messenger RNAs. The expression of these mRNAs varies in different parts of the nervous system. The sequence differences observed are confined to the 5' termini of the messengers and involve alternative splicing events. This variation has clear functional consequences for each putative form of the enzyme and could represent a novel means of regulating catecholamine levels in normal and pathological neurons.
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