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Biomedical subjects

J Maldonado

Publications and source records attributed to J Maldonado.

At least 19 recordsLinked to original sources
PubMed1992

Endobronchial metastases in colorectal adenocarcinoma.

Between 1982 and 1990, 2388 bronchoscopic examinations were carried out in patients with cancer in our hospital. A diagnosis of endobronchial metastasis was established in 30 patients (2.09%), with the following primary tumors in descending order of frequency: breast, large bowel, melanoma, neuroblastoma, leiomyosarcoma and endometrial. Despite the rarity of endobronchial metastases secondary to colon adenocarcinoma, we were able to study 3 cases from our Center. In one case the diagnosis of endobronchial metastasis was simultaneous with that of the primary tumor, and in the other 2 this metastatic complication occurred 16 and 42 months, after the original diagnosis. When this complication occurred, the stage of the disease was advanced in all 3 cases: 2 were Dukes' stage C and one stage D. Although this metastatic location usually implies a very negative prognosis as regards life expectancy, it did not seem to significantly reduce the latter in our patients.

Adenocarcinoma↗
PubMed1992

Evaluation of the mutagenic and genotoxic activities of 48 nitroimidazoles and related imidazole derivatives by the Ames test and the SOS chromotest.

The mutagenic and genotoxic activities of 48 nitroimidazoles and related imidazole derivatives have been evaluated by using modified versions of the Ames test and the SOS Chromotest. Salmonella typhimurium tester strain TA 100 was used with and without metabolic activation in the Ames test and Escherichia coli tester Strain PQ 37 was used with and without metabolic activation in the SOS Chromotest. Including metronidazole and dimetridazole, 45 derivatives were mutagenic and genotoxic. The mutagenic potencies (MP) ranged from 0.127 to 53,717 revertants/nmol while the SOS induction powers (SOSIP) ranged from 0.00131 to 107 IF/nmol. The overall correlation between MP and SOSIP was r = 0.845 (n = 84) as calculated by linear regression analysis. A higher correlation was observed between MP and SOSIP without the S9 mix than with it. Among the imidazole derivatives, the 5-nitroimidazoles with a lactam ring at the 2-position showed the highest MP and SOSIP. The presence of a nitro group at the 5-position was critical for the mutagenicity and the genotoxicity of the derivatives. Substituents at the 1- and 2-positions were also found to modulate these activities.

Animals↗
PubMed1992

[Pulse wave velocity as expression of arterial compliance and its importance in the evaluation of arterial hypertension].

STUDY OBJECTIVE: To determine the arterial compliance through the evaluation of pulse wave velocity. DESIGN: Open study with direct comparison of different groups within a 12 week evaluation period. PATIENTS: 69 patients, 49 with hypertension and 20 normals individuals. INTERVENTIONS: Different groups with the following treatments: Isradipine, Lisinopril, Dilevalol and no therapy. MEASUREMENTS AND MAIN RESULTS: There is marked differences in the pulse wave velocity when hypertensive patients are compared with normal individuals (p < 0.001). In a 12 week therapeutic evaluation there is an improvement in the pulse wave velocity particularly when the arterial pressure was lowered to normal values in the hypertensive patients: Lisinopril (p < 0.005), Isradipine (p < 0.005), Dilevalol (p < 0.025). CONCLUSIONS: It is very easy to evaluate the pulse wave velocity. Arterial compliance, which may be evaluated using the pulse wave velocity, is significantly reduced in hypertensive patients, compared with age-matched control subjects. The use of antihypertensive drugs is associated with changes in arterial compliance. There is a significant decrease in the pulse wave velocity after the administration of ACE inhibitors, calcium channel blockers and beta blockers for an equivalent fall in blood pressure. These observations emphasizes the potential importance of the changes in the large arteries, considered as either an associated factor or a consequence of elevated blood pressure, in the evaluation of the cardiovascular morbidity, and mortality of patients treated for hypertension.

Adult↗
PubMed1992

[Relations between the levels of lipoprotein (a) and results of coronarography in patients with ischemic heart disease. Preliminary results].

The authors make a short revision about Lipoprotein(a) [Lp(a)], which has been referred as an independent risk factor for coronary disease. To confirm this results in a portuguese population, we studied serum Apo(a) [method IRMA.Kit Pharmacia.1 U/L Apo(a) = 1 mg/L Lp(a)], Apo A, Apo B, total cholesterol, HDL-cholesterol, triglycerides, calcium, uric acid, glucose, fibrinogen and ESR in 37 patients who were submitted to postmyocardial infarction coronarography (Judkins technic--Seldinger. Classic incidences. Significative lesions: greater than or equal to 75% in coronary vessels or greater than or equal to 50% in common main nk). The purpose was to search for changes on the plasmatic levels according to the results of the coronarography. The only change observed was in the Lp(a) levels, with important variations (p less than 0.05) between the defined groups: patients without significant coronary disease or disease on just one vessel [media (mean) = 30.1 mg/dl. Standard error (SE) = 7.9 mg/dl.n = 11] and another group of patients with coronary disease of two or three vessels [mean = 50.5 mg/dl.SE = 7.0 mg/dl.n = 26]; among the patients with two vessels disease were found significant changes (p less than 0.02) on Lp(a) levels according to the descending anterior coronary being [mean = 79.5 mg/dl.SE = 4.3 mg/dl.n = 8] or not [mean = 38.5 mg/dl.SE = 14.3 mg/dl.n = 7] implicated. These observations make the suggestion of Lp(a) as a risk factor for coronary disease, and a predictor for the gravity of the coronary disease in myocardial infarction.

Adult↗
PubMed1992

Selectivity of a CaCl2 continuous infusion screening method in rats.

In albino rats the combined use of two methods based on a continuous perfusion of aconitine nitrate (0.15 mg/ml) or calcium chloride (0.4 M) demonstrated the selectivity of the calcium chloride-induced dysrhythmias model. This rapid screening was carried out with antidysrhythmic agents according to the Vaughan-Williams's classification (1): quinidine (class I) 5 mg/kg; atenolol (class II) 2 mg/kg; amiodarone (class III) 10 mg/kg and verapamil (class IV) 2 mg/kg. A compound synthesized in our laboratory was used to verify model selectivity.

Aconitine↗
PubMed1991

Evaluation of in-vitro leishmanicidal activity of hydrazones of thiophene carboxaldehydes against promastigotes of Leishmania infantum and Leishmania tropica.

The lack of leishmanicidal drugs has prompted the synthesis and testing of new hydrazones of thiophene carboxaldehydes against three Leishmania strains. The compounds were obtained by condensation of appropriate hydrazines with thiophene 2-carboxaldehyde (series 1), thiophene 3-carboxaldehyde (series 2), and 5-nitrothiophene-2-carboxaldehyde (series 3). Leishmanicidal activity was assessed against promastigotes of Leishmania strains, grown in-vitro in nutrient broth medium complemented with fresh rabbit blood. The minimal inhibitory concentrations were evaluated against pentamidine, as a reference drug. Several compounds exhibited significant leishmanicidal activity, the best being ten times more active than pentamidine.

Animals↗
PubMed1991

[Primary heart tumors. Report of a clinical case].

The authors describe the case of a 52-year-old patient with several hospitalizations due to acute pulmonary edema, clarified only during the performance of cardiac surgery for the correction of presumable mitral valvular pathology. A leiomiossarcome of the left auricle was concerned, which involved the posterior ring of the mitral valve, the interauricular septum and the orifices of the pulmonary veins. Due to the impossibility of proceeding with the complete resection of the tumor, the tumoral mass was wasted away in order to liberate the involved structures, this followed by chemotherapy. Two years since, the patient shows a generally deteriorated state, submitted to various hospitalizations due to cardiac insufficiency, having been objectivated hepatic metastization and recurrence of the primary neoplasm.

Female↗
PubMed1990

A randomized multicentric study comparing alternating combination chemotherapy (VCMP/VBAP) and melphalan-prednisone in multiple myeloma.

Between January 1985 and December 1988, 386 patients with multiple myeloma were randomized to receive either MP or combination chemotherapy based on alternating cycles of VCMP and VBAP. The major prognostic parameters did not differ significantly between both treatment groups. A significantly higher proportion of objective responses was observed with combination chemotherapy as compared to MP (47.8 vs 32.2, P = 0.01). The median survival for all patients was 33.5 months. So far no significant differences were found when comparing the survival curves from both groups of patients. However, the median survival of MP-treated patients is 26.8 months, whereas the median survival of patients receiving VCMP/VBAP has not yet been reached. The definitive analysis must await the evaluation of all patients entered into the study and a longer follow-up time.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

Significance of intraoperative venographic patterns on the postoperative recurrence and surgical incision placement of pediatric varicoceles.

Intraoperative post-ligation spermatic venography has proved to be a reliable adjunct in pediatric varicocele surgery. In a previous study we described the technique and initial results. In this series of 60 consecutive patients with pediatric varicoceles having intraoperative venography, we specifically studied the collateral venous circulation and crossover veins to characterize the venographic patterns associated with varicocelectomy failure. The relationship of incision site and number of venograms necessary to ensure complete interruption of the internal spermatic system was evaluated to determine if an optimum incision placement exists, minimizing the number of venograms necessary. Our data indicate that the most common etiology of recurrent varicocele in children seems to be residual proximal (central) collateral veins, pelvic collateral veins (that is cremasteric, deferential and crossover veins) rarely seem to contribute to varicocelectomy failure and there is an inherent but low risk of varicocelectomy failure despite radiological evidence of complete internal spermatic vein interruption.

Adolescent↗
PubMed1990

[Embryonal fatty tumors. Lipoblastoma-lipoblastomatosis].

The authors present four cases. The first case is a diaphragmatic-mediastinal, the second one is a cervical-mediastinal one, the third case has a buttock, the last one is a case of hip-thigh. Their ages are one, eight and three years old and the fourth case is seven days old. They appear in axilla, neck, thoracic wall and fat prevertebral tissue, in below three year old children. Despite their benignity, the tumors grow very fast. The complete extirpation is fundamental to avoid relapses, which are presented approximately in a 15 for 100 of the cases. Mutilations are not necessary, since it is a benign tumor. Finally, the authors amply review the literature. They differentiate the concepts of lipoma, hibernoma and lipoblastoma.

Buttocks↗
PubMed1990

[Surgical treatment in tumors of the anterior mediastinum].

Anterior mediastinal tumours (A.M.T.) suppose a diagnostic problem owing to nonspecific clinical signs and symptoms. In the last twenty years, we have seen ten patients with A.M.T., 50 per 100 of which were fortuitous radiologic findings and the remaining 50 per 100 were diagnosed from nonspecific symptoms. Diagnostic imaging techniques were used to classify the anterior location of the tumours. Posterolateral thoracotomy was performed in the first six patients and sternotomy in the remaining four. In conclusion, sternotomy provides a wider surgical field and is to be recommended in A.M.T. surgery. Low morbidity and mortality support an early decision for thoracic surgery.

Adolescent↗
PubMed1989

Nicotine replacement: effects of postcessation weight gain.

The present study examined nicotine replacement effects on postcessation weight gain in smoking cessation clinic volunteers using objective indices of cigarette smoking, gum use, and body weight. After they achieved abstinence, subjects were randomly assigned to either active nicotine or placebo gum conditions for 10 weeks, during which smoking status was carefully monitored. Analyses revealed strong evidence for a gum effect on weight gain, with active gum users gaining a mean total of 3.8 lb compared with 7.8 lb for placebo gum users at the end of the 10-week trial. Evidence for a dose-response relation was found, suggesting that more gum use (greater than or equal to 6.5 pieces/day) resulted in greater weight suppression. Placebo gum subjects reported greater postcessation increases in eating and hunger compared with active gum subjects. The implications of the weight suppression effect of nicotine gum for smoking cessation treatments are discussed.

Adult↗
PubMed1989

Post-remission therapy in acute myeloblastic leukemia. A randomized trial comparing early consolidation plus maintenance versus maintenance therapy alone.

During a 5-year period 203 previously untreated patients with acute myeloblastic leukemia entered an intensive induction chemotherapy regimen with daunorubicin, cytosine arabinoside, 6-thioguanine, vincristine and prednisone (DATOP). The complete remission rate was 64%. Patients in complete remission were randomly assigned to 3 courses of early consolidation with DATOP at lower dosage followed by maintenance chemotherapy, or to the same maintenance regimen in the absence of any consolidation courses. No significant differences were found between these options concerning disease-free survival (median 7.0 vs. 9.8 months; p greater than 0.10) or survival (median 15.8 vs. 19.4 months; p greater than 0.10). This study, in addition to the few previously reported randomized trials, suggests that early low-dose consolidation adds no benefit to maintenance chemotherapy in acute myeloblastic leukemia once complete remission has been achieved.

Adolescent↗
PubMed1989

[Lipomeningocele: review of 44 cases].

On a review of 500 spina bifidas, the authors presents 44 lypomeningoceles (8.8%). During de first two years of age a clinical follow-up with a T.A.C. and myelography is performed. Depending on the symptoms the surgical intervention is performed after two years of age. The authors described the surgical technique. Urological, gastroenterological and orthopedics sequelae are presented and reviewed.

Female↗