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Biomedical subjects

F Consolo

Publications and source records attributed to F Consolo.

At least 37 records · Page 2Linked to original sources
PubMed1988

"Irregular" ventricular parasystole: the influence of sinus rhythm on a parasystolic focus.

Fifteen cases of ventricular parasystole were analyzed to determine whether the interectopic intervals were regular, as expressed by long intervals being exact multiples of the short ones, or not. The regularity of the interectopic intervals was assessed by means of the variation index: the ratio of the maximal difference between various measurements of the parasystolic cycle length and the mean parasystolic cycle length. Three out of 15 cases had a variation index less than 5, and were classified as "regular parasystole." Twelve cases were associated with a variation index greater than 7.5, and were classified as "irregular parasystole." The cases of irregular parasystole were then analyzed to determine whether the variability of the interectopic intervals was casual or dependent on action of the sinus beats. A parasystolic resetting by critically timed sinus impulses (a form of intermittent parasystole) was evident in three cases. The irregularity in the remaining nine cases was due to modulation (viz., due to electrotonic influence exerted by the sinus beats on the parasystolic focus). In every case of modulated parasystole a phase-response curve was constructed, which enabled an analysis of all the interectopic intervals on the basis of a time-dependent effect exerted by the sinus impulses on an otherwise rhythmic parasystolic focus.

Adolescent↗
PubMed1987

Abnormal daily periodicity of serum thyrotropin (TSH) and evidence for defective TSH suppression in a case of non-neoplastic syndrome of inappropriate TSH secretion.

A non-neoplastic syndrome of inappropriate secretion of TSH (ITSHS) was diagnosed in a hemithyroidectomized and clinically euthyroid 44-yr-old man, who also exhibited limping (Perthes' disease), genu valgum, pes supinatus and lateral nystagmus. Computed tomography demonstrated an enlarged sella turcica due to empty sella. Baseline serum T3, T4, free T3, free T4 and TSH fluctuated between 179 and 274 ng/dl, 6.0 and 13.2 micrograms/dl, 4.2 and 6.0 pg/ml, 7.6 and 15.3 pg/ml, and 4.3 and 33.0 microU/ml, respectively. Serum alpha-TSH subunit was repeatedly normal (0.36-0.69 ng/ml) over the follow-up period (greater than 3 yr). No changes in serum liver enzymes and lipids were observed after thyroid hormone administration, whereas red blood cell glucose-6-phosphate dehydrogenase (G-6-PD) and urinary OH-proline were slightly enhanced during 120 micrograms/day L-T3 regimen. This also resulted in an inappropriately normal glucagon-stimulated cAMP levels. Tachycardia was experienced only during L-T3 and very high L-T4 dose treatments. Therefore, the patient showed some evidence for thyroid hormone peripheral refractoriness. Patient's TSH was physiologically responsive to agents (thyrotropin releasing hormone, methimazole, the dopamine antagonists domperidone and sulpiride) known to elicit its release into circulation, while it responded paradoxically to those which normally inhibit TSH secretion. In fact, the infusion of somatostatin (320 micrograms/h) or dopamine (4 micrograms/Kg/min), and the oral administration of bromocriptine or nomifensine (two dopamine agonists) or corticosteroids (dexamethasone) provoked an unexpected elevation of both unstimulated and TRH-stimulated TSH levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Abnormalities in pituitary thyroid axis function tests in patients with paroxysmal supraventricular arrhythmias.

The study was carried out on 60 consecutive patients (23 males and 37 females) aged between 20 and 83 years (means +/- SD, 40.7 +/- 16) who arrived at our Cardiologic Unit with paroxysmal supraventricular arrhythmias (PSVA) including junctional paroxysmal tachycardia (n = 32), atrial fibrillation (n = 13), atrial flutter (n = 1), premature beats (n = 13) and with no obvious cardiovascular causes. Serum thyroxine and triiodothyronine were normal in all patients and thyroid scintiscan revealed normal shape and size thyroids without autonomously functioning nodule(s). Thyrotropin (TSH) response to thyrotropin releasing hormone (TRH) was normal in 44 subjects in whom normal serum free T4 (FT4) and free T3 (FT3) levels were measured. Six patients with normal FT4 and FT3 levels did not respond to TRH. Abnormalities in thyrotropin response to TRH were observed in 10 patients all exhibiting increased FT4 or also FT3 levels. Among these, 5 patients did not respond to TRH, whereas the remaining 5 exhibited a blunted TSH response to TRH. These results suggest that only in a small proportion (5/60) of consecutive patients with PSVA it is possible to recognize a status of "occult thyrotoxicosis" on the basis of the combined evaluation of free thyroid hormones and TSH response to TRH.

Adult↗
PubMed1986

Supernormal modulation of ventricular parasystole: the triphasic phase-response curve.

Modulation of ventricular parasystole by sinus beats has been shown both in vitro and in vivo to result in a classic biphasic phase-response curve. The first clinical presentation of 3 cases of supernormal modulation of ventricular parasystole resulting in a triphasic phase response curve is reported. Supernormal modulation reflects an unexpected early enhancement expedition of the ectopic ventricular impulses. An alternative explantation for the triphasic phase-response curve is the discharge and resetting of the parasystolic focus by critically timed sinus impulses.

Adult↗
PubMed1986

Increased serum thyroglobulin concentrations and impaired thyrotropin response to thyrotropin-releasing hormone in euthyroid subjects with endemic goiter in Sicily: their relation to goiter size and nodularity.

Serum thyroglobulin (Tg), T4, T3, FT4, FT3, TSH concentrations and TSH response to iv TRH (delta TSH) were measured in 56 consecutive patients with (multi) nodular goiter from a severely iodine-deficient endemic goiter area in Northeastern Sicily and in 11 non goitrous euthyroid individuals living in the same area. Serum Tg concentrations were sharply increased in goitrous subjects (453 +/- 476 ng/ml) and related to thyroid size and the presence of nodules (chi 2 = 43.5, p less than 0.0005). Serum TSH levels measured in goitrous patients (2.1 +/- 0.9 microU/ml) were significantly lower than those measured in nongoitrous iodine deficient subjects (3.1 +/- 0.9 microU/ml, p less than 0.001) and decreased with increasing goiter size and nodularity (chi 2 = 27.3, p less than 0.05). A similar pattern was shown by the analysis of the delta TSH (chi 2 = 43.1, p less than 0.0005). These results suggest that at least a part of the largest and multinodular goiters become autonomously functioning with duration and growing in size. In 13 goitrous patients with absent or impaired response to TRH, a significant direct relation was apparent between log-Tg and goiter size and nodularity (r = 0.64) with an inverse relationship between serum FT3 and delta TSH (r = 0.73). A computed program analysis based on the combination of different independent variables (x) including age, thyroid size and nodularity, serum TSH, log-Tg and FT3, indicated the existence of a significant negative relationship between these variables and the TSH response to TRH (r = 0.75, p = 0).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Insulin receptors and insulin sensitivity in normo and hyperinsulinemic obese patients.

The authors have studied insulin receptors on peripheral blood monocytes and insulin sensitivity, evaluated by simultaneous infusion of glucose, insulin and somatostatin in 10 control subjects and in 20 obese patients with normal glucose tolerance. The obese patients have been divided into two groups, normo (NO) and hyperinsulinemic (HO), according to the total insulin response during OGTT. We considered HO patients with insulin response higher than M + 2DS of controls. Obese patients showed, in comparison to the controls, a lower specific binding and higher degree of insulin resistance. The subdivision of obese patients allowed us to distinguish two groups. The first was characterized by basal hyperinsulinemia, normal insulin response to the stimulus, reduced number of insulin receptors and normal or slightly reduced sensitivity. The second group showed high basal and after stimulus insulinemic values, reduced number of insulin receptors and high level of insulin resistance. When we compared the two groups of obeses we found that the first has a shorter duration of obesity and lower blood glucose values after OGTT. However both groups show the same reduction of insulin bound and the same degree of basal hyperinsulinemia. These data suggest that a reduction of insulin receptors is not the main factor responsible for insulin resistance in obesity. Furthermore, the presence of basal hyperinsulinemia and normal insulin sensitivity in our first group suggests that the modification of basal insulin concentrations is not dependent on the presence of insulin resistance.

Adult↗
PubMed1984

Circulating immunoglobulin E (IgE) antibodies to L-thyroxine in a euthyroid patient with multinodular goiter and allergic rhinitis.

A 30-yr-old woman with allergic rhinitis and multinodular goiter developed atopic manifestations on different desiccated thyroid extract treatment. Urticaria was observed when the patient was on L-T4 treatment; no atopy was experienced during L-T3 regimen. Serum total immunoglobulin E (IgE) concentration was 390 +/- 7kU/liter (mean +/- SD) prior to any treatment and rose to 850 +/- 7.5 kU/liter when the patient developed urticaria, but declined to baseline figures while she was on L-T3. Intracutaneous testing was positive for desiccated pork thyroid powder, L-T4 and D-T4, but negative for L-T3, DIT and L-tyrosine. Immunoradioligand analyses of mixtures of patient's serum or precipitated immunoglobulin fraction and of 125I-T4 or of 125I-T3 revealed binding of radiolabeled thyroxine to the patient's serum IgE, in turn bound to anti-human-IgE serum covalently coupled to paper discs. This binding was completely inhibited by the preincubation of immunoglobulin fraction with excess unlabeled L-T4 and D-T4, but not with excess nonradioactive L-T3, thus proving the specificity of the binding. Preadsorption experiments performed with desiccated pork thyroid powder solution mixed with the patient's immunoglobulin fraction suggested binding of some unknown component(s) of desiccated thyroid which was apparently not thyroglobulin. This study provides evidence of IgE antibodies to L-T4 cross reacting with D-T4 and capable of binding 125I-T4 in serum. It also suggests a model for the detection of circulating IgE antibodies to thyroid hormones.

Adult↗
PubMed1983

Correlation between increased serum and tissue L-carnitine levels and improved muscle symptoms in hemodialyzed patients.

A group of 14 uremic patients on intermittent hemodialysis was admitted to a cross-over double-blind trial in order to evaluate serum and muscle carnitine levels before and after 60 days of L-carnitine oral (2 g/day) treatment. The morphology of muscle fragments was studied by light and electron microscopy. Symptoms (asthenia, cramps) occurring during hemodialysis were also recorded. After L-carnitine treatment the blood and muscle levels of the metabolite increased simultaneously to reduced asthenia and cramps. Morphological examination of the muscle of 13 of 14 patients did not reveal any pre- or posttreatment pathological alterations. The presence of nemaline rods was morphologically diagnosed in only one case and was no longer observed at the second biopsy at 2 months of L-carnitine treatment.

Adult↗
PubMed1983

Suppression of demand pacemakers due to spurious signals generated by inactive endocardial electrodes.

We report a case of oversensing observed in a patient with a VVI pacemaker. This phenomenon was provoked by an inactive lead whose tip was in close apposition with the tip of the stimulating electrode. Potentials of large amplitude arose from the contact between these two catheters, causing pacer suppression. These false signals have been revealed both by intracavitary recordings and by standard ECG. In the latter they assumed a P-like shape. Withdrawal of the temporary lead restored normal pacing.

Aged↗
PubMed1983

Plasma and muscle carnitine levels in haemodialysis patients with morphological-ultrastructural examination of muscle samples.

The present study investigates 14 patients on intermittent haemodialysis. Pre-dialysis blood and muscle samples taken for determining plasma free- and acetylcarnitine levels. The tissue fragments were used for light and electron microscopy studies. Our results support the findings of other investigators that patients on haemodialysis generally display decreased free- and acetylcarnitine levels both in plasma and skeletal muscle when compared with control values. Muscle carnitine deficiency was apparently more severe in the longer-term haemodialysis patients. Moreover, a significant correlation (p less than 0.05) between plasma and muscle free-carnitine values was found. Morphologically no pathological alterations were observed in the muscle fibres in 13 of the patients. Light and electron microscopic studies of the muscle fibre of the 14th patient showed a typical nemaline myopathy with rod bodies in the cytoplasm. The muscle free-carnitine concentration in this patient was among the lowest of the group.

Adult↗
PubMed1983

[Erythrocyte filtration in acute myocardial infarction].

In 12 patients with acute myocardial infarction we have studied the behavior of the red blood cell filterability using polycarbonate membranes of 13 mm diameter with pores of 5 mu diameter according to the Reid's method. The samples were drawn soon afterwards the admission and successively every 48 h for a period of about 12 days. In the meantime, erythrocyte sedimentation rate (ESR), fibrinogen, leukocyte, platelet and alpha 2-macroglobulin changes have been determined. The average initial filterability values in patients with infarction were 0.84 +/- 0.20, while in control subjects were 0.58 +/- 0.15. During the observation period, a statistically significant increase of filterability after 48 h (1.06 +/- 0.24) and after 96 h (0.88 +/- 0.21) was observed. Using the statistical analysis we have noticed a strong correlation among filterability and leukocytes and ESR. The effect of leukocytes is due to the reduction of membrane pores through which red blood cells filter. The correlation with the ESR shows the presence of a plasma factor different from fibrinogen and capable of transforming the red blood cell aggregation by reducing their filterability.

Blood Sedimentation↗
PubMed1982

Parasystolic ventricular tachycardia with variable exit block.

This case is an example of ventricular parasystolic tachycardia associated with variable expressions of ectopic-ventricular (E-V) exit block. The exit block manifested with 2:1, 3:2, 4:3 and higher ratios of E-V conductions, interspaced with periods of 1:1 conduction. Concealed E-V conduction of the ectopic impulse could also be deduced.

Aged↗
PubMed1982

Immunoglobulin binding of thyroid hormones in a case of Waldenstrom's macroglobulinemia.

This paper describes a case of hypothyroidism in a patient with Waldenström's disease in which the evidence of thyroid failure was accompanied by an abnormal binding of thyroid hormones in the gamma-globulin fraction. A 68-yr-old patient with Waldenström's disease appeared to be hypothyroid by clinical and laboratory criteria. Serum TSH was elevated; serum T3 (measured by RIA) was low, while T4 levels were undetectable or very high according to the method used. Serum free thyroid hormones were in the hypothyroid range, and both antithyroglobulin and antimicrosomal thyroid antibodies were undetectable. The thyroid gland was normal at autopsy. Elevated binding of radiolabeled thyroid hormones by the patient's serum gamma-globulins was demonstrated by reverse flow electrophoresis and cellulose acetate electrophoresis. This binding could be inhibited by preincubation of serum samples with unlabeled T4 and T3, but not with human thyroglobulin, rT3, DIT, or MIT. Immunoprecipitation of the patient's serum incubated with [125I]T4 or [125I]T3 showed that 56% of T4 and 30% of T3, respectively, were precipitated using an antihuman immunoglobulin M(IGM) serum; only [125I]T4 was precipitable (22%) by the addition of an antihuman immunoglobulin G(IgG) serum. The binding of the thyroid hormones by IgM and IgG, which reduced T4 and T3 availability for their metabolic action at the tissue level, could have contributed to the clinical picture.

Aged↗