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Biomedical subjects

M Baroni

Publications and source records attributed to M Baroni.

At least 73 records · Page 4Linked to original sources
PubMed1990

[Pseudoischemic T waves: a possible electrophysiologic mechanism].

An electrophysiologic study has been performed in 7 patients with giant stable inversion of the T waves in the precordial ECG leads and without any organic heart disease. The study was particularly directed to evaluate the specific properties of the conductive system. The main results of the study point out the presence of absolute (prolonged HV interval, delay of ventricular activation time) or relative (RRP of the left bundle branch greater than RRP of the right one) conduction delays already in basic conditions or occurring after ajmaline (1 mg/Kg iv). Moreover, repolarization normalized during repetitive high rate atrial extrastimuli in the beats where ventricular activation time shortened and not during regular pacing. On the other hand, repolarization worsened whenever an impairment of infra or intrahisian conduction occurred. During His bundle pacing an inversion of the T waves preceded a left bundle branch conduction delay. The present data make us to hypothesize that, in these patients with pseudoischemia, a delay of activation of the initial vectors of the QRS in the left side, by amplifying the electrical gradient between the 2 ventricles, can be the underlying mechanism causing the repolarization abnormalities.

Adult↗
PubMed1989

Breast carcinoma and plasma 17-beta-estradiol binding.

The data relating to plasma steroid binding and transport (usually measured with dehydrotestosterone) are controversial. The plasma E2 binding of 79 breast carcinoma patients, 19 premenopausal and 60 postmenopausal, were compared to 46 controls, 21 premenopausal and 25 postmenopausal. In this study the authors removed the endogenous steroids with charcoal, incubated the plasma with 17-beta-E2 in non-saturation conditions, and used ammonium sulfate to precipitate the complex. The authors chose 17-beta-E2 as ligand because the plasma steroid binding system has not been shown to be homogeneous and because this binding function may vary independently for the different steroids. In these patients, the E2 binding was significantly (P less than 0.01) increased (85 +/- 11 pg/ml and 73 +/- 13 pg/ml in premenopausal and postmenopausal) compared to the normal controls (59 +/- 7 pg/ml and 58 +/- 5 pg/ml in premenopausal and postmenopausal women. It is still unclear whether this is a primary increase of the binding capacity or a reaction of the host for sequestering excess circulating E2. However, the small percentage of false-positives and false-negatives suggests that E2 binding could be used as a tumor marker in breast carcinoma.

Breast Neoplasms↗
PubMed1989

Mediastinal malignant carcinoid with Cushing's syndrome: immunohistochemical and ultrastructural study.

A case of thymic atypical carcinoid with Cushing's syndrome and unfavorable clinical course is reported. Immunohistochemical analysis reveals distinct staining of tumor cells for ACTH, neuron-specific enolase, chromogranins (CG) and S-100 protein and with PHE-5 monoclonal antibody. At an ultrastructural level, the cells are undifferentiated with only a few neurosecretory granules. In the present case, immunohistochemical stainings for CG and with PHE-5 antibody seem reliable diagnostic tools, easily demonstrating the neuroendocrine nature of the neoplasm. NSE immunoreactivity can be an additional criterion. S-100-positive cells, which are present throughout the tumor, recall 'sustentacular cells', described in other neuroendocrine tumors.

Adrenocorticotropic Hormone↗
PubMed1989

[Idiopathic restrictive cardiomyopathy: clinical, hemodynamic, histologic and prognostic profile].

Idiopathic restrictive cardiomyopathy is a rare myocardial disease characterized by restrictive physiology without a specific histologic basis. To assess its clinical, hemodynamic, morphologic and prognostic details we retrospectively evaluated all the patients hospitalized in our Institute from 1974 to 1988. Nine patients, aged 42 +/- 16 years, M/F ratio = 0.29, who represent 64% of all the restrictive myocardial diseases biopsied were identified. Severe cardiac heart failure (3-4 NYHA) and arrhythmias (ventricular and supraventricular) were extremely common. The electrocardiogram showed several non specific signs: low voltage of QRS in peripheral leads (4/7), pseudo-infarctional aspects (3/7), mono or biventricular hypertrophy (3/7) disturbance of ventricular conduction (3/7), aspecific abnormalities of ventricular repolarization (3/7). All patients showed a prolonged QTc. M-mode and 2-dimensional echocardiography demonstrated in 6 cases biatrial enlargement, normal or slightly enlarged ventricles, normal or moderately depressed fractional shortening; biventricular concentric hypertrophy was detected in 3 cases, asymmetrical septal hypertrophy in 1. Five patients showed pericardial effusion. Cardiac catheterization disclosed an increase of left and right ventricular end-diastolic pressures (8/8) with a dip-plateau pattern and/or characteristic W waveform in the atrial pressure tracing (9/9). Passive pulmonary hypertension was detected in 6/9 cases. The cardiac index was decreased in 4/8 cases. Left ventricular angiography showed mitral regurgitation in 5/8 patients, tricuspidal in 5/8. Ejection fraction was decreased in 3/8 cases. Endomyocardial biopsy showed interstitial fibrosis (8/9), cellular hypertrophy and/or nuclear alterations (7/9), slight endocardial thickening (2/9). At a mean follow-up of 22 +/- 15 months 3 patients died and 2 underwent heart transplantation. In conclusion idiopathic restrictive cardiomyopathy is one of the most frequent forms of restrictive myocardial diseases in our geographic area. Severe congestive heart failure and arrhythmias are extremely common. The disease can be suspected by clinical, electrocardiographic and echocardiographic features, but the final diagnosis requires cardiac catheterization and endomyocardial biopsy. Prognosis is severe and heart transplantation must be considered in the cases with severe heart failure.

Adolescent↗
PubMed1988

Accumulation of processing intermediates of the RAS2 protein in strain 112 of Saccharomyces cerevisiae.

Strain 112 (RAS1 RAS2) contains a naturally occurring mutation which significantly retards processing of the RAS2 gene product. This mutation, resulting in the accumulation of precursor forms of RAS2 protein, has been assigned by genetic analysis to a single chromosomal locus distinct from the RAS2 locus. In addition to the known precursor molecule of 41000 daltons (p41), 112 cells accumulate within the soluble fraction an intermediate form of RAS2 (p40-1), which migrates, in SDS-polyacrylamide gel, between p41 and the fully processed, membrane-bound 40,000 daltons (p40) product. We propose for RAS2 protein processing the following sequence of events: p41 greater than p40-1 greater than p40 where p40-1 represents a RAS2 intermediate required for the targeting of the protein to the plasma membrane.

Electrophoresis, Polyacrylamide Gel↗
PubMed1988

Lumbar myelography with iopamidol: a methodological approach to the investigation of side effects.

Pathophysiology of adverse reactions occurring during myelography with non-ionic contrast agents, such as iopamidol, seem related to their direct action on the nervous system. The authors try a multivariate approach, involving neurophysiological, neuropsychological and neurochemical parameters on a pilot group of twelve subjects. Any possible change in the above examinations is thoroughly analyzed and correlated to the postulated neurotoxic properties of contrast media.

Central Nervous System Diseases↗
PubMed1987

A phase II trial of 5-fluorouracil and high-dose intravenous leucovorin in gastric carcinoma.

Twenty-eight patients with advanced measurable gastric carcinoma were treated with leucovorin (dl-CF; folinic acid; dl-5-formyltetrahydrofolic acid) 500 mg/m2 administered as a two-hour infusion and 5-fluorouracil (5-FU) 600 mg/m2 intravenous (IV) push midinfusion. Treatment was administered weekly for 6 weeks followed by a 2-week rest. Twenty-five patients were evaluable for response. Twelve of them had received previous combination chemotherapy that included 5-FU. Median age was 59 years, and median Eastern Cooperative Oncology Group (ECOG) performance status was 2. Three patients had partial responses and two of them had been treated previously with 5-FU. Twelve patients had stable disease. Five of these patients had subjective improvement with improved performance status and/or decreased dysphagia. The 95% confidence interval for response is 3% to 32%. Median survival time for all 28 patients enrolled in the study was 22 weeks. Toxicity was moderate and consisted primarily of diarrhea. Myelosuppression, skin rash, and increased lacrimation also occurred. Plasma concentrations of the active reduced folates, I-CF and 5-methyltetrahydrofolic acid (5-CH3FH4), were greater than the 10 mumol/L levels that potentiate 5-FU activity in in vitro models, for more than four hours in all five patients in whom pharmacokinetics were studied. 5-FU and high-dose dl-CF has activity in patients with gastric carcinoma including patients who had previously progressed on 5-FU-containing combinations. Further study in a larger patient population is necessary to determine the usefulness of this regimen in gastric carcinoma.

Adenocarcinoma↗
PubMed1987

Medroxyprogesterone acetate at very high doses in postmenopausal advanced breast cancer patients.

Twenty-six postmenopausal consecutive patients with advanced breast cancer were treated with very high medroxyprogesterone acetate doses (4000 mg/day orally for 30 days and then 3000 mg/day orally until progression or intolerance). The dominant metastatic lesion was bone in 13 patients, soft tissue in 3 patients and viscera in 10 patients (C.I. = V/ST + 0 = 0.62). An objective partial remission was achieved in 16 pts (61%), no change in 8 (31%), progression in 2 (8%). The median duration of objective remission was 7.5+ months with a median survival of 14.5+ months in responders. Toxicity was minor and only two patients discontinued the treatment because of side-effects. These results confirm the utility of medroxyprogesterone acetate at very high doses in these patients and the feasibility of this kind of dose.

Adult↗
PubMed1987

[Ambulatory electrocardiography in patients with angina pectoris].

In the diagnosis of ischemic heart disease, long-term ECG recording has several distinct advantages. It allows one to relate patient symptoms to cardiac disturbances and to detect asymptomatic events, reveals the possible ischemic genesis of arrhythmias, and it is the most suitable method to assess the acute and chronic effectiveness of treatment and the evolution of the disease. In spite of these advantages, Holter monitoring has several limitations: the analysis of a single lead, is responsible in most systems for the low sensitivity in detecting ischemia occurring in unexplored regions; the period of 24-48 hours may not be sufficient for screening patients due to the unpredictable spontaneous variability of the disease; a common standard of analysis is still lacking even if the European Communities concerted action in Ambulatory Monitoring could represent the solution to this problem. Nevertheless the role of Holter monitoring appears essential in the ambulatory screening of patients with suspected ischemia for a better characterization of patients with ascertained myocardial ischemia, and for the evaluation of treatment and of the evolution of the disease.

Angina Pectoris↗
PubMed1986

The immune response to influenza vaccination in diabetic patients.

The immune response of diabetic patients to influenza vaccination was examined in 31 patients, 10 with Type 1 (insulin-dependent) diabetes and 21 with Type 2 (non-insulin-dependent diabetes), and in 19 normal subjects. Each received a single intramuscular injection of the 3 virus strains (A/Chile,A/Philippines,B/USSR) anti-influenza vaccine recommended by WHO. The antibody titre and the cell-mediated immune response to the 3 virus strains, as evaluated by the generation of activated lymphocytes and enumeration of B lymphocytes, were studied before and 18 h, 72 h and 1, 2, 3 and 6 weeks after vaccination. Overall, the humoral and cell-mediated immune responses were normal in both groups of patients. However, patients with Type 1 diabetes showed a statistically significant increase (p less than 0.01) of antibody titre of the A/Chile and an increased percentage of B lymphocytes one week after vaccination compared to age-matched control subjects. Four out of 21 patients with Type 2 diabetes had no antibody response to all 3 virus strains. A significant reduction (p less than 0.01) of the percentage of activated cells possessing receptors for interleukin-2 was observed 72 h after vaccination in patients with Type 2 diabetes compared to age-matched control subjects. None of the patients who received the vaccine developed influenza in the course of the following year. These results suggest that valid protection against the influenza virus can be obtained in patients with Type 1 and Type 2 diabetes.

Adult↗
PubMed1986

Interaction of cAMP with the CDC25-mediated step in the cell cycle of budding yeast.

Addition of exogenous cAMP to cultures of the start mutant cdc25-1 of Saccharomyces cerevisiae shifted to restrictive temperature causes a partial reversion of the mutated phenotype, with a marked increase of the percentage of budded cells. This effect is coupled to a progression in the cell cycle, as demonstrated by DNA histograms obtained by flow cytometry. Moreover cdc25 cells have a high intracellular cAMP content also at restrictive temperature, and no change in the cAMP content was seen during a transition from restrictive to permissive temperature. These data suggest that CDC25 gene product allows cell proliferation by interacting with a cAMP-mediated mechanism.

Cell Cycle↗
PubMed1986

Molecular cloning and regulation of the expression of the MET2 gene of Saccharomyces cerevisiae.

The MET2 gene of Saccharomyces cerevisiae, which codes for homoserine-O-acetyltransferase, a key enzyme in methionine biosynthesis, was isolated by complementation of a met2 mutant strain of S. cerevisiae with a yeast gene bank. A 3.9-kb genomic fragment contains the entire gene, as demonstrated by genetic and molecular analysis of the integrative transformants. A polyadenylated mRNA of 1700 nt is detected by Northern blot hybridization with a MET2 probe. The level of this mRNA decreases by addition of exogenous methionine or of S-adenosylmethionine, suggesting a transcriptional regulation. The level of specific mRNA and the enzyme activity found in transformants that bear the MET2 gene on a multicopy plasmid suggest that also a post-transcriptional regulatory mechanism may be operative in budding yeast.

Acetyltransferases↗
PubMed1986

QT prolongation and torsade de pointes ventricular tachycardia produced by Ketanserin.

A 65-year-old man with arterial hypertension received oral treatment with Ketanserin, a new drug, during a period of five months. He developed marked QT interval prolongation and have several Stokes-Adams attacks. A Holter recording obtained during one of these episodes showed torsade de pointes ventricular tachycardia. The arrhythmias occurred during maximum QT interval prolongation. The correlation between Ketanserin and QT interval prolongation was evaluated by using several Holter studies during administration and withdrawal of the drug. The effect of Ketanserin on the QTc interval was analyzed retrospectively in six patients who had been taking the drug orally. Following a period of four to eight months, the QTc interval was prolonged by the drug (5 to 31%, mean 17%) in five patients. We conclude that torsade de pointes is a potential hazard of long-term treatment with Ketanserin.

Adult↗