PubMed Health⌕ Search

Biomedical subjects

P Lopes

Publications and source records attributed to P Lopes.

At least 19 recordsLinked to original sources
PubMed2006

Ventilatory thresholds assessment from heart rate variability during an incremental exhaustive running test.

The present study examined whether the ventilatory thresholds during an incremental exhaustive running test could be determined using heart rate variability (HRV) analysis. Beat-to-beat RR interval, V(.-)O (2), V(.-)CO (2) and V(.-) (E) of twelve professional soccer players were collected during an incremental test performed on a track until exhaustion. The "smoothed pseudo Wigner-Ville distribution" (SPWVD) time-frequency analysis method was applied to the RR time series to compute the usual HRV components vs. running speed stages. The ventilatory equivalent method was used to assess the ventilatory thresholds (VT1 and VT2) from respiratory components. In addition, ventilatory thresholds were assessed from the instantaneous components of respiratory sinus arrhythmia (RSA) by two different methods: 1) from the high frequency peak of HRV ( FHF), and 2) from the product of the spectral power contained within the high frequency band (0.15 Hz to fmax) by FHF (HF x FHF) giving two thresholds: HFT1 and HFT2. Since the relationship between FHF and running speed was linear for all subjects, the VTs could not be determined from FHF. No significant differences were found between respective running speeds at VT1 vs. HFT1 (9.83 +/- 1.12 vs. 10.08 +/- 1.29 km x h (-1), n.s.) nor between the respective running speeds at VT2 vs. HFT2 (12.55 +/- 1.31 vs. 12.58 +/- 1.33 km x h (-1), n.s.). Linear regression analysis showed a strong correlation between VT1 vs. HFT1 (R (2) = 0.94, p < 0.001) and VT2 vs. HFT2 (R (2) = 0.96, p < 0.001). The Bland-Altman plot analysis reveals that the assessment from RSA gives an accurate estimation of the VTs, with HF x FHF providing a reliable index for the ventilatory thresholds detection. This study has shown that VTs could be assessed during an incremental running test performed on a track using a simple beat-to-beat heart rate monitor, which is less expensive and complex than the classical respiratory measurement devices.

Adult↗
PubMed2006

Assessment of ventilatory thresholds from heart rate variability in well-trained subjects during cycling.

The purpose of this study was to implement a new method for assessing the ventilatory thresholds from heart rate variability (HRV) analysis. ECG, VO2, VCO2, and VE were collected from eleven well-trained subjects during an incremental exhaustive test performed on a cycle ergometer. The "Short-Term Fourier Transform" analysis was applied to RR time series to compute the high frequency HRV energy (HF, frequency range: 0.15 - 2 Hz) and HF frequency peak (fHF) vs. power stages. For all subjects, visual examination of ventilatory equivalents, fHF, and instantaneous HF energy multiplied by fHF (HF.fHF) showed two nonlinear increases. The first nonlinear increase corresponded to the first ventilatory threshold (VT1) and was associated with the first HF threshold (T(RSA1) from fHF and HFT1 from HF.fHF detection). The second nonlinear increase represented the second ventilatory threshold (VT2) and was associated with the second HF threshold (T(RSA2) from fHF and HFT2 from HF.fHF detection). HFT1 , T(RSA1), HFT2, and T(RSA2) were, respectively, not significantly different from VT1 (VT1 = 219 +/- 45 vs. HFT1 = 220 +/- 48 W, p = 0.975; VT1 vs. T(RSA1) = 213 +/- 56 W, p = 0.662) and VT2 (VT2 = 293 +/- 45 vs. HFT2 = 294 +/- - 48 W, p = 0.956; vs. T(RSA2) = 300 +/- 58 W, p = 0.445). In addition, when expressed as a function of power, HFT1, T(RSA1), HFT2, and T(RSA2) were respectively correlated with VT1 (with HFT1 r2 = 0.94, p < 0.001; with T(RSA1) r2 = 0.48, p < 0.05) and VT2 (with HFT2 r2 = 0.97, p < 0.001; with T(RSA2 )r2 = 0.79, p < 0.001). This study confirms that ventilatory thresholds can be determined from RR time series using HRV time-frequency analysis in healthy well-trained subjects. In addition it shows that HF.fHF provides a more reliable and accurate index than fHF alone for this assessment.

Adult↗
PubMed2006

E-cadherin expression during urothelial carcinogenesis induced by N-butyl-N-(4-hydroxybutyl) nitrosamine in rats.

An alteration in the expression of E-cadherin has been observed in many epithelial neoplasms. No data exist, however, for the expression of this protein in an animal model for urinary bladder cancer. The present study investigated the expression of E-cadherin in rat urothelial preneoplastic lesions and tumours induced by oral administration of N-butyl-N-(4-hydroxybutyl) nitrosamine, during 10, 15 and 20 weeks. Simple hyperplasia and squamous metaplasia showed a similar E-cadherin pattern when compared with normal urothelium, with its expression confined to cell membrane. Thirty eight percent of the nodular hyperplasia, 41.4% of the dysplasia and 100% of the papillomas showed a weak E-cadherin expression. All papillary neoplasm of low malignant potential, low-and high-grade papillary carcinoma, and invasive carcinoma revealed an abnormal staining pattern with an increase in cytoplasm reactivity and discontinuous cell membrane positivity. The loss of expression for low-grade papillary carcinoma versus simple hyperplasia, nodular hyperplasia and dysplasia was statistically significant (p = 0.0001, p = 0.007 and p=0.008, respectively). There was a similar decrease in E-cadherin expression for papillary neoplasm of low malignant potential versus simple hyperplasia, nodular hyperplasia and dysplasia (p = 0.0001; p = 0.001 and p=0.0001, respectively). These results suggest that alteration in the expression of this adhesion molecule in rat may be indicative of tumour progression in N-butyl-N-(4-hydroxybutyl) nitrosamine-induced bladder cancer.

Animals↗
PubMed2005

Effect of exercise intensity and repetition on heart rate variability during training in elite trotting horse.

RR intervals of ten elite trotting horses were recorded during an interval training session performed on track. This study examined two hypotheses. Firstly, like in humans, the hyperpnea combined with a decrease in cardiac autonomic control on heart rate during heavy exercise could result in a prevalence of high frequency heart rate variability. Secondly, this prevalence could increase with the heavy exercise repetition. Two exercise intensities were compared: moderate (ME) and heavy (HE). Furthermore, heavy exercise repetitions were compared between the beginning and the end of the interval training session. When comparing ME and HE periods: heart rate was significantly lower (155 +/- 12 vs. 210 +/- 9 ms, p < 0.001), LF spectral energy (0.04 - 0.2 Hz) was significantly higher (ME: 6.94 +/- 4.80 and HE: 0.24 +/- 0.14 ms(2) . Hz (-1), p < 0.001) whereas HF (0.2 - 2 Hz) was significantly lower (ME: 7.09 +/- 2.24 and HE: 10.60 +/- 3.64 ms(2) . Hz (-1), p < 0.05). In relative terms, ME showed similar results in both LFn (LF/LF+HF) and HFn (HF/LF+HF) whereas HE showed a large prevalence of HFn energy compared to LFn (p < 0.001). The difference in LF/HF ratio between the two exercise conditions was significant (1.14 +/- 0.92 vs. 0.09 +/- 0.12, p < 0.001). Exercise repetition induced a significant increase in heart rate between the beginning and the end of the interval training session (207 +/- 10 beats . min (-1) vs. 212 +/- 9 beats . min (-1), p < 0.001) whereas LF energy decreases (1.54 +/- 1.65 vs. 0.32 +/- 0.24 ms(2) . Hz (-1), p < 0.01) and HF energy remained constant (10.79 +/- 4.10 vs. 10.40 +/- 3.35 ms(2) . Hz (-1), NS). This study confirmed the results observed in humans during heavy exercise conditions with a large prevalence of HF in contrast to LF, this prevalence increasing with exercise repetitions. The observed decrease in LF/HF ratio could provide an index of hyperpnea in horses during interval training.

Animals↗
PubMed2004

[A new hysteroscopic method for sterilization: 45 patients].

OBJECTIVES: French study of the feasibility and safety of a new hysteroscopic method for sterilization under local anesthesia. MATERIALS AND METHODS: After information, all candidates for sterilization were invited to choose between the laparoscopic or hysteroscopic methods. Essure performed under local analgesia was used for hysteroscopic sterilization. Operative time, intensity of pain using a visual analog scale and secondary discomfort were recorded. RESULTS: A cohort of 57 women were enrolled in this study and 45 chose hysteroscopy. Two were excluded after discovery of an intrauterine pathology during the hysteroscopic procedure. Placement of a bilateral device was successful in 41 patients (90.3%); under local analgesia only in 29 patients (68.3%). Mean time needed for device placement was 25.6 9 min and hospital stay was 9.8 hours. Pain was scored 56/100 on the visual analog scale. CONCLUSION: Laparoscopy remains the mainstay method used for sterilization but does involve risks. Hysteroscopic device placement seems to be safe, rapid and an effective procedure.

Adult↗
PubMed2004

Effects of prolonged strenuous exercise (marathon running) on biochemical and haematological markers used in the investigation of patients in the emergency department.

OBJECTIVES: To investigate the effects of strenuous exercise on commonly used biochemical and haematological variables in subjects running the 2002 London marathon. METHODS: 34 healthy volunteers (7 female, 27 male) were recruited for the study. Blood was taken before the start (at registration) and immediately after completion of the marathon. Samples were analysed for urea and electrolytes, liver function tests, creatine kinase (CK), CK-MB isoenzyme, myoglobin, troponin I, full blood count, a clotting screen, and D-dimers. The results before and after exercise were compared. Pearson's correlation coefficients were calculated for all variables. RESULTS: Significant increases were found in CK, CK-MB, aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and myoglobin following the marathon. However, there was no significant change in the level of troponin I. There was also evidence of activation of the coagulation and fibrinolytic cascades following the marathon, with a reduction in activated partial thromboplastin time, a reduction in fibrinogen, and an increase in D-dimers. CONCLUSIONS: The results confirm previous individual studies on marathon running and the biochemical and haematological tests routinely carried out in hospital. These are affected by prolonged exercise, and "abnormal" results in these tests may be normal after prolonged exercise and therefore not diagnostic of a disease process. The results of investigations in patients who have been exercising should be interpreted with caution.

Adult↗
PubMed2004

Epidemiology of injuries in adventure racing athletes.

OBJECTIVES: To assess the demographics and training characteristics of adventure racing athletes in the United Kingdom, the prevalence and anatomical distribution of hazardous encounter, and overuse injury in this population, and the effects these injuries have on training. METHODS: A retrospective training and injury questionnaire for the previous 18 months was distributed to 300 adventure racing athletes at two national race meetings. The definition of an injury was "any musculoskeletal problem causing a stop in training for at least one day, reduction in training mileage, taking of medicine, or seeking of medical aid." RESULTS: The data were derived from the responses of 223 athletes. Advanced level athletes did 11 (4) sessions and 17 (8) hours of training a week (mean (SD)). An injury was reported in the previous 18 months by 73% of the respondents. The most common site of acute injury was the ankle (23%) and of chronic/overuse injury, the knee (30%), followed by the lower back, shin, and Achilles tendon (12% each). There were significant correlations (p<0.01) between the hours spent cycling per week and number of acute injuries, and between the number of days off per week and number of chronic/overuse injuries. Injuries resulted in an average of 23 days training cessation or reduction. CONCLUSIONS: Acute injuries were sustained mainly as a result of the nature of the terrain over which athletes train and compete. In overuse injuries lack of adequate rest days was a significant contributing factor. Only a small proportion of training time was spent developing flexibility and core stability.

Acute Disease↗
PubMed2003

[Sterilization for women using a hysteroscopy technique under local anaesthesia].

OBJECTIVES: and methods The July 2001 law allows capable and consenting adult women to be sterilized after a period of reflection of 4 months and signature of an informed consent formula. The first French study on hysteroscopic tubular sterilization under local anaesthesia using expanding titanium, steel and nickel implants, is reported. RESULTS: From February to October 2002, 25 women, with a mean age of 40 years, having conceived 2 or more children, benefited from this technique. The duration of the surgical procedure was a mean of 26 minutes (range: 16 to 57 minutes). In 2 women presenting with uterus retroversion, catheterisation of the fallopian tubes was impossible. Local anaesthesia was only used in 15 women, and led to the reduction in the number of days of hospitalisation. CONCLUSION: This pilot study confirms the feasibility of trans-cervical sterilization of women under local anaesthesia.

Adult↗
PubMed2003

Expression of cell-cycle regulatory proteins and their prognostic value in superficial low-grade urothelial cell carcinoma of the bladder.

AIMS: Cell-cycle regulatory proteins are important indicators in determining progression trough the cell-cycle and progression to invasive cancer in patients presenting with superficial bladder cancer. We performed an immunohistochemical study in order to evaluate the prognostic value of the expression of p16, p27, pRb, p53 and Ki-67 in superficial grade I and II papillary urothelial cell carcinoma of the bladder. METHODS: p16, p27, p53, pRb and Ki-67 immunoexpression was studied in 14 pTa, 35 pT1a and 7 pT1b bladder tumours at presentation and at recurrence of their tumours. The recurrence-free survival and the progression-free survival were analysed according to these regulatory cell-cycle proteins expression. RESULTS: For survival in univariate analysis a high Ki-67 labelling index was a poor prognostic factor for recurrence-free and progression-free survival (P=0.0014 and P=0.012, respectively). Ki-67 labelling index was also an independent recurrence-free survival prognostic factor (P=0.0005). The p16, p27, p53 and pRb immunoreactivity was not significantly associated with recurrence or progression rate in this group of bladder carcinomas. CONCLUSIONS: These data suggest that the Ki-67 labelling index can be a reliable marker in predicting recurrence and/or progression in superficial low-grade bladder carcinomas and may be relevant in planning adjuvant therapy.

Adult↗
PubMed2002

Heart rate variability: response following a single bout of interval training.

We investigated the effect of exercise on heart rate variability by analysing the heart rate power spectrum prior to, and 1 and 72 h following, an interval training session. Subjects initially performed a graded test to exhaustion to determine maximal oxygen uptake (VO(2) max) and the running speed at which VO(2) max was first attained (vVO(2) max). The training session was completed on a separate day and comprised six 800 m runs at 1 km x h (-1) below vVO(2) max. Prior to the training session (pre), 1 h following the training session (+ 1h), and 72 h following the training session (+ 72 h), subjects sat quietly in the laboratory for 20 min whilst breathing frequency was maintained at 12 breath x min (-1). Cardiac cycle R-R interval data were collected over the final 5 min of each 20 min period and analysed by means of autoregressive power spectral analysis to determine the high frequency (HF) and low frequency (LF) components of heart rate variability. Heart rate was higher, and the standard deviation of the R-R intervals was lower, at + 1 h than for pre or + 72 h (p < 0.05). The HF and the LF components of heart rate variability were also lower (p < 0.05) for + 1 h than for pre or + 72 h when the data were expressed in ms(2). However, no changes in the LF:HF ratio were observed, and the changes in the HF and LF components disappeared when the data were expressed as a fraction of the total power. Whilst these findings illustrate the importance of controlling the timing of exercise prior to the determination of heart rate variability, the time course of the post-exercise heart rate variability response remains to be quantified.

Adult↗
PubMed2001

Aerodiol versus the transdermal route: perspectives for patient preference.

OBJECTIVE: to compare the efficacy, tolerability and user preference of Aerodiol intranasal and transdermal patch administration of 17 beta-estradiol for climacteric symptoms. METHODS: an open-label, multicenter, crossover trial in which recently postmenopausal women were randomized to receive either Aerodiol 300 microg daily (n=176), or transdermal 17 beta-estradiol (reservoir patches delivering 50 microg/day), 2 patches per week (n=185), for 12 weeks, followed by 4 weeks of the alternative treatment. Efficacy was assessed primarily by the Kupperman index at the end of each treatment period. User satisfaction was assessed by questionnaire at weeks 12 and 16, and at week 16 the women chose which treatment they preferred to use for a further 40-week period. RESULTS: Aerodiol and transdermal patch therapy produced marked and similar reductions in the Kupperman index and the incidence of hot flushes at weeks 12 and 16. The reduction in the Kupperman index at week 12 was statistically equivalent for the two treatments. The tolerability of both treatments was good, with similar numbers of emergent adverse events reported in both groups. The incidence of moderate or severe mastalgia, however, was significantly lower with Aerodiol (P=0.02). Significantly more women chose to continue treatment with Aerodiol than with the transdermal patch (66 vs. 34%, P<0.001). When all women had experienced both treatments, reported levels of satisfaction were significantly higher with Aerodiol than with transdermal therapy (P<0.001 for all six categories assessed). CONCLUSIONS: Aerodiol and transdermal patch treatments were of similar efficacy and tolerability. Levels of user preference and satisfaction, however, were higher with Aerodiol, which should contribute towards good long-term compliance with this therapy.

Administration, Cutaneous↗
PubMed2001

Apocrine ductal carcinoma in situ of the breast: histologic classification and expression of biologic markers.

Apocrine ductal carcinoma in situ (ADCIS) has been called a special type of ductal carcinoma in situ (DCIS) because the histologic grading is considered difficult using the classification schemes that have been proposed for common DCIS. However, ADCIS encompasses a spectrum of lesions with different morphologic aspects ranging from minimally atypical to overtly malignant. To define a classification scheme for ADCIS, 35 cases (22 pure and 13 associated with invasive carcinoma) were selected on the basis of conventional morphology on hematoxylin and eosin (H&E)-stained sections. Each case was assigned to 1 of 3 histologic grades (low, intermediate, and high) based on nuclear morphology and the presence of necrosis. In addition, the expression of hormone receptors p53, bcl-2, c-erbB-2, and Ki-67 was evaluated by immunohistochemistry, and the DNA ploidy was determined by image cytometry. Fifteen cases were classified as high histologic grade, 10 as low histologic grade, and the other 10 as intermediate grade. All but 4 cases, irrespective of grade, had the same hormonal immunophenotype: androgen receptor positivity (97.1%) and estrogen receptor and progesterone receptor negativity (94.3% and 97.1% respectively). Twenty-one cases (61.8%) showed p53 expression, and 47.1% of the cases were positive for c-erbB-2. The median positivity for Ki-67 was 5.2%. ADCIS has a unique morphologic and hormonal profile, distinct from common DCIS, deserving a specific classification. The proposed classification scheme allows for categorization of ADCIS according to the most important morphologic features already seen in common DCIS, ie, nuclear grade and necrosis. The expression of biologic markers other than hormonal receptors and bcl2 in ADCIS seems in general to be similar to that in common DCIS. Ki-67 and c-erbB-2 are expressed more frequently in intermediate and high histologic grade ADCIS.

Adult↗
PubMed2000

The long-term effectiveness of preventive strategies for osteoporosis in postmenopausal women: a modeling approach.

Based on data from the literature, we have developed a computer-based simulation model to compare the long-term effectiveness of different preventive strategies of osteoporotic fractures. The Markov model comprises 25 states, including states which describe women distributed according to three levels of fracture risk, fractures states, post-fracture states and a death state. We chose eight standard preventive strategies, which we compare with the 'No Treatment' reference strategy. The first two strategies consist in treating all 50-year-old women for 5 or 10 years with hormone replacement therapy (HRT). Strategies 3 and 4 aim at assessing a 5-year course of treatment with bisphosphonates in osteopenic and osteoporotic 65- or 75-year-old women. Strategies 5 and 6 combine 5 years of HRT in all 50-year-old women with 5 years of bisphosphonates in osteopenic and osteoporotic women at 65 or 75 years. The last two strategies simulate 10 years of HRT in all 50-year-old women, followed by strategy 3 or strategy 4. Simulated life expectancy and mean ages of fracture occurrence fit well with the observed data. All the preventive strategies tested reduced the number of fractures. Early 10-year HRT in all women, plus 5 years of bisphosphonates in women at risk of fractures at 65 or 75 years, are the most effective strategies, with an 18.4-19.0% reduction in all fractures, and a 25.6-26.1% reduction in the number of hip fractures. Strategy 2 has a similar outcome, thus demonstrating the value of treatment started early and sustained over a long period. The strategies implemented later, S3 and S4, only concern women at risk (i.e., osteopenic or osteoporotic), and are less effective, with a 1.5-2.1% decrease in all fractures. The combined strategies, S5 and S6, produce intermediate results: a 12.9-13.5% reduction in the number of all fractures and a 17.5-17.9% reduction in hip fractures.

Aged↗
PubMed2000

Randomized comparison of intranasal and transdermal estradiol.

OBJECTIVE: To compare the efficacy and patient acceptability of intranasal versus transdermal 17 beta-estradiol (E2) delivery systems for postmenopausal symptoms. METHODS: Postmenopausal women were randomly assigned to intranasal 17 beta-E2, 300 microg daily (n = 176) or transdermal 17 beta-E2 (delivering 50 microg/day), two patches per week (n = 185) for 12 weeks, followed by a 4-week period with the alternate treatment. Efficacy was compared between groups using the Kupperman Index and vasomotor symptoms at week 12. Patient acceptability was compared by patient choice of administration route and by questionnaire at week 16. RESULTS: Intranasal and transdermal therapy produced significant reductions in the Kupperman Index and in the occurrence of hot flushes and night sweats at week 12. Alleviation of climacteric symptoms was statistically equivalent in the two treatment groups (P <.001). The difference between groups in the Kupperman Index score of -0.5 +/- 0.9 (95% confidence interval -2.3, 1.3) was within the predetermined interval of equivalence. Both therapies were well tolerated with similar adverse event rates, except for moderate and severe mastalgia which was significantly less frequent with intranasal E2 (7.2%) than with the patch (15.5%, P =.02). Sixty-six percent of patients chose to continue the intranasal therapy and 34% the transdermal therapy (P <.001). Satisfaction was greater with intranasal therapy at week 16 (P <.001). CONCLUSION: Intranasal and transdermal estrogen delivery systems had equivalent efficacy and similar safety profiles. Intranasal therapy was the patients' choice for long-term treatment.

Administration, Cutaneous↗