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Biomedical subjects

V Valentín

Publications and source records attributed to V Valentín.

10 recordsLinked to original sources
PubMed2001

High-dose mitoxantrone and cyclophosphamide without stem cell support in patients with high-risk and advanced breast carcinoma: a Phase II multicentric trial.

BACKGROUND: Currently employed high-dose regimens for patients with breast carcinoma consist mainly of single-cycle combinations of alkylating agents. In a previous Phase I trial, the authors developed a tandem high-dose combination of two cycles of mitoxantrone and cyclophosphamide for the treatment of patients with metastatic breast carcinoma (MBC) and high-risk breast carcinoma (HRBC). Treatment was delivered with granulocyte-colony stimulating factor (G-CSF) but without stem cell support to avoid potential tumor cell reinfusion. The objective was to validate the safety and obtain preliminary efficacy assessment of this combination in a Phase II trial. METHODS: Fifty-three patients were included: 27 patients with MBC and 26 patients with HRBC. After standard induction treatment, patients received two cycles of mitoxantrone 25 mg/m2 and cyclophosphamide 4000 mg/m2 separated by a 4-week interval. Patients received G-CSF and ciprofloxacin until hematologic recovery. Follow-up was performed in an outpatient setting. RESULTS: One hundred one of 106 projected cycles (95%) were delivered. The mean dose intensities achieved were mitoxantrone 5.8 mg/m2 per week and cyclophosphamide 933 mg/m2 per week. Infection developed in 46% of the cycles, and platelet transfusions were required in 42%. Nonhematologic toxicity was mainly Grade 3 emesis. There were no toxic deaths. In 17 evaluable patients with MBC, 13 patients (77%) had response improvements, including 7 complete responses (41%). CONCLUSIONS: Treatment with two cycles of mitoxantrone 25 mg/m2 and cyclophosphamide 4000 mg/m2 with G-CSF but without stem cell support was well tolerated. The dose intensities achieved approach those obtained with conventional high-dose therapy. This combination warrants further investigation as an alternative to conventional high-dose regimens.

Adult↗
PubMed2001

[Clopidogrel in acute coronary syndromes with non-ST elevation. Clinical implications of the CURE trial].

The pivotal role of the platelets in the genesis of acute coronary syndromes emphasises the importance of an early and sustained antiplatelet therapy. The CURE trial shows that clopidogrel in addition to aspirin achieves this double goal, with a 20% relative risk reduction in the primary composite endpoint of cardiovascular death, myocardial infarction or stroke in the first 30 days. The benefits are apparent as early as the first 24 hours of starting the treatment. There is also a consistent benefit of clopidogrel across all groups, including both high-risk and low-risk patients, which overrides an excess of 6 out of a thousand cases treated per year of bleeds, which require transfusion. Several clinical implications of the CURE trial are analyzed: the kind of patients who benefit more on clopidogrel, how long should treatment with clopidogrel continue, cost-benefit consideration, the impact of the findings on the benefit of the use of clopidogrel, on the use of glycoprotein IIb/IIIa receptor antagonists, clopidogrel pretreatment and long term therapy in patients undergoing percutaneous coronary intervention and bleeding risk with surgery.

Angina, Unstable↗
PubMed1992

The effects of selective stellate ganglion manipulation on ventricular refractoriness and excitability.

The effects of selective stellate ganglion stimulation or stellectomy on ventricular excitability were studied in 30 open chest mongrel dogs anesthetized with alpha-chloralose. The effective refractory period (ERP) and strength interval curves (stimulus intensity [S2] = twice the diastolic threshold [ERP], and 2, 3, 5, 7, and 14 mA) were determined using bipolar epicardial electrodes placed in the mid-anterior wall of the right ventricle (RV) and the mid-posterolateral wall of the left ventricle (LV) during left stellate ganglion stimulation (LSGSt, n = 8) or right stellate ganglion stimulation (RSGSt, n = 8), or after left stellectomy (LSGEx, n = 7) or right stellectomy (RSGEx, n = 7). LSGEx prolonged ERP-LV (172 +/- 9 vs 167 +/- 8 msec, P < 0.05) and ERP-RV (163 +/- 10 vs 158 +/- 14 msec, P < 0.05). RSGEx prolonged ERP-LV (168 +/- 17 vs 162 +/- 15 msec, P < 0.01) and ERP-RV (166 +/- 14 vs 160 +/- 13 msec, P < 0.01), and the times of the strength interval curves obtained for each S2 intensity in both ventricles. LSGSt decreased ERP-LV (157 +/- 11 vs 163 +/- 12 msec, P < 0.01) and ERP-RV (147 +/- 18 vs 157 +/- 17 msec, P < 0.05), and the times of the strength interval curves obtained for each S2 intensity in both ventricles. RSGSt did not significantly decreased ERP-LV (152 +/- 11 vs 156 +/- 9 msec); however, it significantly shortened the times of the strength interval curves obtained for S2 intensities of 2 and 7 mA in the LV, and shortened ERP-RV (139 +/- 10 vs 145 +/- 7 msec, P < 0.01) and the times of the strength interval curve for S2 intensities of 2, 3, and 5 mA in the RV. A significant interaction (MANOVA test) was observed between the ventricle studied and the ganglion stimulated for S2 intensities of 2 and 3 mA, and between the effect of stimulation and the ganglion stimulated for S2 intensities of 3 and 14 mA. To conclude, selective stellectomy prolonged epicardial ventricular refractoriness in both the mid-anterior wall of the RV and the mid-posterolateral wall of the LV; the magnitude of the epicardial excitability variations in both areas was different during selective stellate ganglion stimulation.

Analysis of Variance↗
PubMed1989

[Experimental study of the effects of ATP on sinus automatism and atrioventricular node conduction].

A study was made of 14 thoracotomized dogs under i.v. sodium thiopental anesthesia; the effects of 1.5 mg/kg intravenous ATP on sinus node automatism and atrio-ventricular conduction were investigated. In 7 dogs (group A) ATP was administered under control conditions and following successive intravenous administrations of atropine (1 mg/kg), aminophylline (5 mg/kg) and propranolol (0.6 mg/kg). The remaining 7 dogs (group B) received ATP following atropine (1 mg/kg), isoproterenol (0.4 microgram/kg/min.), and aminophylline (5 mg/kg). An analysis was made of the percentage variations in cardiac cycle length during spontaneous rhythm and of the AH interval during atrial pacing at a fixed rate. In group A the negative dromotropic and chronotropic effects of ATP under control conditions decreased in 5 cases following atropine, although the average decrease was not statistically significant. On adding aminophylline, a statistically significant decrease was observed in the effects of ATP, and following propranolol the drop in negative chronotropic effect of ATP provoked by aminophylline was maintained. In group B, and following prior atropinization, the negative chronotropic and dromotropic effects of ATP were maintained in the presence of isoproterenol. As in group A, aminophylline significantly reduced the effects of ATP. To conclude: in the thoracotomized dog under sodium thiopental anesthesia, 1) atropine does not prevent the negative chronotropic and dromotropic actions of ATP, although the effect of the latter is decreased in a large percentage of cases; 2) sympathetic beta stimulation following prior atropinization does not prevent ATP action; 3) aminophylline in the atropinized dog noticeably reduces the effects of ATP, and 4) this action of aminophylline is effective in the presence of sympathetic beta stimulation.

Adenosine Triphosphate↗
PubMed1985

[Quantification of concealed conduction in the atrioventricular node].

Twenty-eight anaesthetized open-chest mongrel dogs were used. Programmed atrial pacing was used and Hisian electrograms recorded through endocavitary electro-catheters to study and quantify the concealed conduction of non-transmitted atrial impulses in the A-V node. An exponential model was used in three situations to quantify the nodal conduction during incremental atrial pacing: a) during 1:1 conduction, b) during 2:1 nodal block, and c) during pacing, coupling an atrial impulse delivered at fixed intervals and blocked in the A-V node to each transmitted impulse. The relation between intranodal conduction times was analyzed both with and without the presence of blocked impulses, and the quotient between the obtained functions in situations b, c and situation a was determined. In a subgroup of 13 dogs the study was repeated following pharmacological block of the autonomic nervous system. In dogs with autonomic block, this relation always tended to decrease when the atrial pacing rate increased. The variations in the group of dogs with intact autonomic nervous systems were not homogeneous. During pacing with coupled block impulses, the progressive removal of conduction curves obtained for each coupling interval with respect to those obtained during 1:1 transmission, expresses the interval with respect ot those obtained during 1:1 transmission, expresses the lesser influence of the blocked impulses on decreasing their coupling interval.

Animals↗