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Biomedical subjects

J Pardo

Publications and source records attributed to J Pardo.

At least 55 records · Page 3Linked to original sources
PubMed2000

Metabolic and neuromuscular adaptations to endurance training in professional cyclists: a longitudinal study.

The aim of this longitudinal study was to analyze the changes in several metabolic and neuromuscular variables in response to endurance training during three defined periods of a full sports season (rest, precompetition and competition). The study population was formed by thirteen professional cyclists (age +/- SEM: 24+/-1 years; mean V(O2 max) approximately 74 ml kg(-1) min(-1)). In each testing session, subjects performed a ramp test until exhaustion on a cycle ergometer (workload increases of 25 W min(-1)). The following variables were recorded every 100 W until the tests: oxygen consumption (V(O2) in l min(-1)), respiratory exchange ratio (RER in V(CO2) V(O2)(-1)) and blood lactate, pH and bicarbonate concentration [HCO3(-)]. Surface electromyography (EMG) recordings were also obtained from the vastus lateralis to determine the variables: root mean square voltage (rms-EMG) and mean power frequency (MPF). RER and lactate values both showed a decrease (p<0.05) throughout the season at exercise intensities corresponding to submaximal workloads. In contrast, no significant differences were found in mean pH or [HCO(3-)]. Finally, rms-EMG tended to increase during the season, with significant differences (p<0.05) observed mainly between the competition and rest periods at most workloads. In contrast, precompetition MPF values increased (p<0.05) with respect to resting values at most submaximal workloads but fell (p<0.05) during the competition period. Our findings suggest that endurance conditioning induces the following general adaptations in elite athletes: (1) lower circulating lactate and increased reliance on aerobic metabolism at a given submaximal intensity, and possibly (2) an enhanced recruitment of motor units in active muscles, as suggested by rms-EMG data.

Adaptation, Physiological↗
PubMed2000

Metastatic osteosarcoma presenting as a small-bowel polyp. A case report and review of the literature.

Gastrointestinal metastases of osteosarcoma are an extraordinarily rare event and, as far as we can determine, have been reported previously only 5 times; these cases represent an unusual pattern of progression. We describe a 21-year-old man with an osteosarcoma of the right tibia that was removed 4 years previously. Two years later, the patient showed lung metastases. At his most recent presentation, he complained of abdominal pain, nausea, vomiting, and anorexia. Radiologic examination revealed an abdominal mass close to the jejunum and 3 nodules in the liver. One metastasis was an ulcerated and pedunculated polypoid mass located in the mucosa of the bowel, and the other involved the entire thickness of the jejunum. This unusual phenomenon represents an alteration in the natural history of osteosarcoma as a result of increased long-term survival.

Adult↗
PubMed1999

Fetal middle-cerebral and umbilical artery flow assessments after glucose challenge test.

OBJECTIVE: To determine whether a change occurs in fetal middle-cerebral and umbilical artery flow after glucose challenge testing. METHOD: Fetal middle-cerebral and umbilical artery flow was assessed by Color Dopppler technology in 21 pregnant patients before and after the 50-g glucose challenge test. The resistance index (IR) was evaluated separately for each vessel. Statistical significance was determined by Chi-square test and repeated measurement analysis with two co-variates. RESULTS: After glucose ingestion the RI was significantly decreased in the middle-cerebral artery, but not in the umbilical artery. A significant increase in RI was recorded in the umbilical artery when maternal plasma glucose level exceeded 102 mg%. CONCLUSION: Maternal ingestion of glucose significantly alters blood flow velocimetry in the fetal middle-cerebral and umbilical arteries. These changes may lead to the misinterpretation of normal results. It is therefore recommended that sonographic flow velocimetry assessment not be performed early after concentrated glucose ingestion.

Adult↗
PubMed1999

An association between viral genes and human oncogenic alterations: the adenovirus E1A induces the Ewing tumor fusion transcript EWS-FLI1.

Malignant transformation of human cells requires the accumulation of multiple genetic alterations, such as the activation of oncogenes and loss of function of tumor suppressor genes or those related to genomic instability. Among the genetic alterations most frequently found in human tumors are chromosomal translocations that may result in the expression of chimeric products with transforming capability or are able to change the expression of oncogenes. We show here that the adenovirus early region 1A (E1A) gene can induce a specific human fusion transcript (EWS-FLI1) that is characteristic of Ewing tumors. This fusion transcript was detected by RT-PCR in normal human fibroblasts and keratinocytes after expression of the adenovirus E1A gene, as well as in human cell lines immortalized by adenoviruses. Cloning and sequencing of the RT-PCR product showed fusion points between EWS and FLI1 cDNA identical to those detected in Ewing tumors. In addition, we detected a chimeric protein by western blot analysis and immunoprecipitation and a t(11,22) by fluorescent in situ hybridization. This association between a single viral gene and a specific human fusion transcript indicates a direct link between viral genes and chromosome translocations, one of the hallmarks of many human tumors.

Adenovirus E1A Proteins↗
PubMed1999

Short-term effects of marathon running: no evidence of cardiac dysfunction.

PURPOSE: The purpose of this study was to analyze the short-term effects of a marathon race (Madrid Marathon) on both markers of cardiac damage and echocardiographic parameters in a group of 22 runners (17 male and 5 female; 34 +/- 5 yr; VO2max: 55.7 +/- 9.1 mL x kg(-1) x min(-1) with a wide range of fitness levels. METHODS: Venous blood samples were collected from each subject 48 h before the race, at race finish, and 6, 24, and 48 h postexercise for the determination of myoglobin, total creatine kinase catalytic activity (total CK), mass concentration of creatine kinase isoenzyme MB (CK-MB mass), and cardiac isoforms of troponin T and I (TnT-c and TnI-c, respectively). In addition, echocardiographic parameters (M-mode two-dimensional and Doppler analysis) indicative of both left ventricular (LV) systolic and diastolic function were obtained three times from each runner: 2-5 d before the race, at race finish, and 24-36 h after exercise. RESULTS: Except in one subject, levels of TnT-c and TnI-c were within normal limits (<0.1 ng x mL(-1)) in all the samples collected before or after the race. Overall LV systolic function was not altered by marathon running. Finally, LV diastolic function was transiently altered after the race since the ratio between peak early and late transmitral filling velocities (E/A) was significantly reduced at race finish (P < 0.01) and returned to resting levels after 24-36 h. CONCLUSIONS: Our findings suggest that marathon running does not adversely affect the hearts of healthy individuals independently from their training status.

Adult↗
PubMed1999

Determination of the maximum steady state of lactate (MLSS) in saliva: an alternative to blood lactate determination.

Based on previous research which shows parallelism between the saliva and blood lactate response during incremental exercise, we hypothesized that a "maximum salivary lactate steady state" (saliva-MLSS) might exist. Thus, the aim of the present investigation was to establish 1) which lower limit for the increase in salivary lactate concentration during a constant workload (i.e., from the 10th to the 20th min) test could be used to determine the saliva-MLSS and 2) if the exercise intensity corresponding to the saliva-MLSS is identical to that evoking the (blood) MLSS. Twelve male amateur athletes of mean ( +/- SD) age 24 +/- 5 year were selected for the study. Based on the results of a previous maximal cycle ergometer test for lactate threshold (LT) determination, each subject performed consecutive constant workload tests of 20-min duration on separate days for MLSS determination. Blood and saliva (25 microl) samples were collected at 0, 10, and 20 min during the tests for lactate determination. A Student's t-test for paired data demonstrated that a salivary lactate increase of 0.8 mM corresponded to the saliva-MLSS. At this value, indeed, no significant differences were observed between the mean V(.)O(2) and W values corresponding to the MLSS and the saliva-MLSS. In conclusion, the present findings indicate that 0.8 mM is the lower limit for the increase in saliva lactate concentration during a constant load test and thus is that which might be used as a reference to determine saliva-MLSS. Furthermore, saliva-MLSS might be used as an alternative to MLSS determination in blood samples.

Adult↗
PubMed1999

Physiological parameters determined at OBLA vs. a fixed heart rate of 175 beats x min-1 in an incremental test performed by amateur and professional cyclists.

A blood lactate concentration of 4 mmol x l-1 (OBLA) is frequently used as an indicator of the maximal steady state of lactate (MLSS) for workload planning in training programs. The aim of the present investigation was to compare several metabolic parameters determined at OBLA and at a fixed heart rate of 175 beats x min-1 (HR175) in amateur cyclists (AC) and professional cyclists (PC). Sixteen AC and 22 PC performed an exercise test on a cycle ergometer following a ramp protocol (25 W x min-1, 70-80 rpm) to exhaustion. Gaseous exchange was monitored throughout the test. VO2, %VO2 max, and power output (W) corresponding to OBLA and HR175 were determined and mean values compared using a Student's t-test. Findings indicated higher VO2 max and W in general in PC (p<0.01), and higher VO2 and W at OBLA and HR175 in PC (p<0.01). No significant difference was found between values determined at OBLA and HR175 in the AC group, while in the PC group, VO2, %VO2 max, and W were higher at OBLA. These observations suggest the possible use of a fixed, reference HR of 175 beats x min-1 to determine the exercise intensity corresponding to OBLA in amateur cyclists. This was not the case for the professional cyclists.

Exercise↗
PubMed1999

[Wegener's granulomatosis: localization in the subglottic space].

In the paper is presented a localized form of Wegener's granulomatosis. This entity being considered as incipient stage of the disease. Its better knowledge and consequent early diagnosis has contributed to increase the clinic pictures. We report one of these cases sitting on the subglottic space, in a 40-years-old woman, beginning with a serious dyspnea. Several clinic aspects of the disease are emphasized as well the immunologic procedures helping to the diagnosis and to day's classifications. Finally, the better prognosis of localized forms, because its excellent response to immunosuppresants, is stressed.

Adult↗
PubMed1999

Pelvic abnormalities in hysterectomized patients-role of early postoperative ultrasonographic evaluation.

OBJECTIVE: To assess the incidence of post-hysterectomy pelvic fluid collection in the early postoperative period and to study its natural history. STUDY DESIGN: Cross-sectional, prospective, observational study. PATIENTS AND METHODS: The study sample comprised 36 consecutive patients undergoing hysterectomy for benign conditions in our department. All patients underwent two pelvic ultrasonographic examinations, the first on the third postoperative day and the second one year later. All postoperative complications were thoroughly evaluated. RESULTS: Thirty-two patients completed the study evaluations. Abnormal ultrasonographic findings were detected in 4 of them on the early postoperative scan. Three (9.4% of the sample) had pelvic fluid collections which persisted on the follow-up scan. The fourth patient had a simple ovarian cyst 4 cm in diameter which disappeared on follow-up. None of the patients with pelvic fluid collections had a febrile morbidity during the postoperative course. CONCLUSIONS: Transvaginal ultrasonography can detect asymptomatic early postoperative pelvic fluid collections and enables conservative management, thereby reducing patients stress, medical costs, and the need for unnecessary interventions.

Ascitic Fluid↗
PubMed1999

[Chronic atrial flutter: an infrequent manifestation of sick sinus syndrome. Clinical case].

We report a 41 years old female, previously operated of an atrial septal defect, presenting with a persisting atrial flutter. Sinus node dysfunction became evident during an electrophysiological study at the moment of interrupting the flutter with electrical stimulation. The patient was treated with his bundle ablation and implantation of a definitive pacemaker. After one year of follow up, she is devoid of symptoms.

Adult↗
PubMed1998

Synthesis and potent antifolate activity and cytotoxicity of B-ring deaza analogues of the nonpolyglutamatable dihydrofolate reductase inhibitor Nalpha-(4-amino-4-deoxypteroyl)-Ndelta-hemiphthaloyl- L-ornithine (PT523).

Six new B-ring analogues of the nonpolyglutamatable antifolate Nalpha-(4-amino-4-deoxypteroyl)-Ndelta-hemiphthaloy l-L-ornithine (PT523, 3) were synthesized with a view to determining the effect of modifications at the 5- and/or 8-position on dihydrofolate reductase (DHFR) binding and tumor cell growth inhibition. The 5- and 8-deaza analogues were prepared from methyl 2-L-amino-5-phthalimidopentanoate and 4-amino-4-deoxy-N10-formyl-5-deaza- and -8-deazapteroic acid, respectively. The 5,8-dideaza analogues were prepared from methyl 2-L-[(4-aminobenzoyl)amino]-5-phthalimidopentanoate and 2, 4-diaminoquinazoline-6-carbonitriles. The Ki for inhibition of human DHFR by the 5-deaza and 5-methyl-5-deaza analogues was about the same as that of 3 (0.35 pM), 11-fold lower than that of aminopterin (AMT, 1), and 15-fold lower than that of methotrexate (MTX, 2). However the Ki of the 8-deaza analogue was 27-fold lower than that of 1, and that of the 5,8-dideaza, 5-methyl-5,8-dideaza, and 5-chloro-5,8-dideaza analogues was approximately 50-fold lower. This trend was consistent with the published literature on the corresponding DHFR inhibitors with a glutamate side chain. In colony formation assays against the human head and neck squamous carcinoma cell line SCC25 after 72 h of treatment, the 5- and 8-deaza analogues were approximately as potent as 3, whereas the 5,8-dideaza analogue was 3 times more potent. 5-Methyl and 5-chloro substitution was also favorable, with the 5-methyl-5-deaza analogue being 2. 5-fold more potent than the 5-deaza analogue. However the effect of 5-methyl substitution was less pronounced in the 5,8-dideaza analogues than in the 5-deaza analogues. The 5-chloro-5,8-dideaza analogue of 3 was the most active member of the series, with an IC50 = 0.33 nM versus 1.8 nM for 3 and 15 nM for MTX. The 5-methyl-5-deaza analogue of 3 was also tested at the National Cancer Institute against a panel of 50 human tumor cell lines in culture and was consistently more potent than 3, with IC50 values in the low-nanomolar to subnanomolar range against most of the tumors. Leukemia and colorectal carcinoma cell lines were generally most sensitive, though good activity was also observed against CNS tumors and carcinomas of the breast and prostate. The results of this study demonstrate that B-ring analogues of 3 inhibit DHFR activity and tumor cell colony formation as well as, or better than, the parent compound. In view of the fact that 3 and its B-ring analogues cannot form polyglutamates, their high cytotoxicity relative to the corresponding B-ring analogues of AMT is noteworthy.

Antineoplastic Agents↗
PubMed1998

Physiological differences between professional and elite road cyclists.

The purpose of this study was to compare the physiological responses of professional and elite road cyclists during an incremental cycle ergometer test. Twenty-five elite cyclists (EC; 23+/-1 yr) and 25 professional cyclists (PC; 25+/-2yr) performed a ramp protocol (increases of 25 W x min(-1)) during which the following parameters were measured: oxygen consumption (VO2), pulmonary ventilation (VE), ventilatory equivalents for oxygen and carbon dioxide (VE x VO2(-1) and VE x VCO2(-1), respectively), respiratory exchange ratio (RER), ventilatory thresholds 1 and 2 (VT1 and VT2, respectively), blood lactate, and electromyographic activity (EMG) of the vastus lateralis. Significant differences existed between the two groups mainly at submaximal intensities, since both VT1 and VT2 occurred at a higher exercise intensity (p<0.001) in PC than in EC (VT2: 80.4+/-6.6 vs 87.0+/- 5.9% VO2max in EC and PC, respectively). Lactate levels showed a similar response in both groups at low-to-moderate intensities (< 300 W), and thereafter blood lactate was significantly higher in EC. Finally, the "electromyographic threshold" (EMGT) occurred at a significantly higher intensity (p < 0.05) in PC when compared to EC (64.7+/-14.2 vs 56.0+/-14.9% VO2max, respectively). It was concluded that, in comparison with EC, PC exhibit some remarkable physiological characteristics such as a high VT2, an important reliance on fat metabolism even at high power outputs, and several neuromuscular adaptations.

Adaptation, Physiological↗
PubMed1998

[Torsade de Pointes and demand endocavitary pacemaker. A case report].

We report a 81 years old female with a severe aortic insufficiency, treated with diuretics and antidepressants admitted due to recurrent syncopal episodes. During the first syncopal episode, an atrioventricular block was detected and an endocavitary demand pacemaker implanted. Two years later, she had a new syncope without evidences of pacemaker failure. The EKG during pacemaker rhythm showed a prolonged QT interval. During hospital monitoring, she presented a self limited polymorphic ventricular tachycardia (Torsade de Pointes). Consequently, the pacemaker was programmed at a greater frequency, and the QT interval shortened from 0.73 to 0.56 sec. Thereafter, the patient no longer had tachycardia or syncopal episodes, after one year of follow up.

Aged↗
PubMed1998

Abnormal sonographic endometrial findings in asymptomatic postmenopausal women: possible role of antihypertensive drugs.

OBJECTIVE: The purpose of this study was to evaluate the possible effect of the antihypertensive agent nifedipine (a calcium channel antagonist) on the endometrium of asymptomatic menopausal women by using transvaginal sonography, hysteroscopy, and endometrial sampling. DESIGN: Eighty-five asymptomatic postmenopausal women with an ultrasonographically detected endometrial thickness of more than 7 mm were examined. The study group comprised 43 women treated with nifedipine (30-60 mg/day) for mild to moderate hypertension for at least 1 year, and the control group comprised 42 normotensive women. All participants underwent transvaginal sonography, hysteroscopy, and, if necessary, endometrial biopsy. RESULTS: Of the 85 patients, 53 were found to have atrophic endometrium, 36 (83.7%) in the study group and 17 (40.5%) in the control group. The difference between the groups was statistically significant (p < 0.05). There were three cases of hyperplasia and three cases of carcinoma of the endometrium, with similar rates in the two groups. CONCLUSIONS: Among asymptomatic postmenopausal patients with sonographically thickened endometrium, atrophic endometrium was found to be significantly more prevalent in those using calcium channel antagonists to control hypertension than in those who were normotensive controls. The presence of endometrial hyperplasia and malignancy in the study group underscores the importance of meticulous endometrial evaluation whenever sonographically thickened endometrium is encountered.

Aged↗
PubMed1998

Ultrasonographic evaluation of hysterectomized patients with and without concomitant adnexectomy?

OBJECTIVE: To present our experience with the use of ultrasonography in the evaluation of hysterectomized patients. METHODS: The study group was comprised of 100 consecutive women referred to our ambulatory unit for pelvic sonographic evaluation between April 1, 1996 and March 31, 1997. Inclusion criteria were previous hysterectomy for a benign condition with or without concomitant bilateral salpingo-oophorectomy and available medical and gynecological histories. RESULTS: No significant difference was observed in the rate of abnormal ultrasonographic findings among the patients who had had bilateral salpingo-oophorectomy 5/50 and those who had not (8/50). There was also no significant difference in pelvic mass rate between the patients who were receiving hormone replacement therapy and those who were not. The sensitivity of sonography in our study was 100% and the positive predictive value, 84.5%. CONCLUSIONS: Sonography is a useful diagnostic tool in the follow-up and management of post-hysterectomy patients.

Aged↗