Biomedical subjects

Ignacio Alonso

Publications and source records attributed to Ignacio Alonso.

8 recordsLinked to original sources

PubMed2006

Role of sonography in the diagnosis of axillary lymph node metastases in breast cancer: a systematic review.

OBJECTIVE: The purpose of our study was to evaluate the accuracy of sonography and sonographically guided biopsy in the preoperative diagnosis of metastatic invasion of the axilla in patients with breast carcinoma. MATERIALS AND METHODS: We performed a MEDLINE search (keywords, "sonography" OR "ultrasound" AND "axillary") and a manual search of the references of relevant studies and reviews of preoperative diagnosis on sonography of possible axillary metastases. The gold standard required was axillary lymph node dissection; we accepted sentinel node biopsy as an alternative gold standard. Considering the sonographic findings and the results of the sonographically guided biopsy, the sensitivity and specificity were calculated using metaanalysis. We also checked the existence of heterogeneity of the summary results. RESULTS: Sixteen articles were selected. In sonography of axillae without palpable nodes, and using lymph node size as the criterion for positivity, sensitivity varied between 48.8% (95% confidence interval, 39.6-58%) and 87.1% (76.1-94.3%) and specificity, between 55.6% (44.7-66.3%) and 97.3% (86.1-99.9%). When lymph node morphology was used as the criterion for positivity, sensitivity ranged from 26.4% (15.3-40.3%) to 75.9% (56.4-89.7%) and specificity, from 88.4% (82.1-93.1%) to 98.1% (90.1-99.9%). The results are different if axillae with palpable nodes are included. The sonographically guided biopsy shows a sensitivity that varies between 30.6% (22.5-39.6%) and 62.9% (49.7-74.8%) and a specificity of 100% (94.8-100%). Many of the summary results obtained after meta-analysis show a heterogeneity that disappears, on occasion, on excluding the studies that use a double gold standard. CONCLUSION: Axillary sonography is moderately sensitive and fairly specific in the diagnosis of axillary metastatic involvement. Sonographically guided biopsy of the sonographically suspicious nodes somewhat increases the specificity, which reaches 100%. Negative sonographic results do not exclude axillary lymph node metastases.

Axilla↗

PubMed2004

Circadian time-qualified tolerance intervals for ambulatory blood pressure monitoring in the diagnosis of hypertension.

The large-amplitude circadian pattern in blood pressure of healthy subjects of both genders suggests that the constant threshold currently used to diagnose hypertension should be replaced by a time-specified reference limit reflecting the mostly predictable blood pressure variability during the 24 h. Accordingly, we derived circadian time-specified reference standards for blood pressure as a function of gender. We studied 743 normotensive Caucasian volunteers (400 men and 343 women), 45.7 +/- 16.5 (mean +/- SD) years of age. Blood pressure was measured by ambulatory monitoring at 20-min intervals during the day and at 30-min intervals at night for 48 consecutive hours. Data from each blood pressure series were synchronized according to the rest-activity cycle of each individual in order to avoid differences among subjects in actual times of daily activity. Data were then used to compute 90% circadian tolerance intervals for each gender separately. The method, derived on the basis of bootstrap techniques, does not need to assume normality or symmetry in the data and, therefore, it is highly appropriate to describe the circadian pattern of blood pressure variability. Results reflect expected changes in the tolerance limits as a function of gender and circadian sampling time, as well as upper blood pressure limits below the thresholds currently used for diagnosing hypertension, especially for women. The use of these time-dependent tolerance limits for the computation of a hyperbaric index as a measure of blood pressure excess has already been shown to provide a reproducible and high-sensitivity test for the diagnosis of hypertension, which can also be used to evaluate treatment efficacy.

Adult↗

PubMed2003

[Circadian blood pressure variation in normal pregnancy, gestational hypertension, and preeclampsia].

BACKGROUND AND OBJECTIVE: Changes in circadian variation of blood pressure could be used either to predict preeclampsia or to assess its severity. With the objective of identifying potential differences in blood pressure at the early stages of pregnancy, we examined and compared the characteristics of circadian variability in blood pressure in healthy and complicated pregnant women who were systematically monitored throughout gestation. SUBJECTS AND METHOD: We analyzed 2,014 blood pressure series sampled through ambulatory monitoring for 48 hours once every 4 weeks from the first obstetric visit until delivery. The study included 205 women with uncomplicated pregnancy, 92 with gestational hypertension and 31 with preeclampsia. The circadian pattern of blood pressure variation for each group and trimester of gestation was established by means of a population multiple-components analysis. RESULTS: Differences in the 24-hour mean between healthy and complicated pregnancies were highly significant in all trimesters (p < 0.001), with values of 15.1 and 9.1 mmHg for systolic and diastolic blood presure, respectively, in the third trimester of pregnancy. The 24-hour mean of systolic/diastolic blood pressure for complicated pregnancies was always below 120/72 mmHg. Results further indicated similar circadian characteristics between gestational hypertension and preeclampsia in the first trimester of pregnancy. The difference between these two groups in the 24-hour mean was significant in the second trimester for systolic (3 mmHg; p = 0.002) but not diastolic blood pressure (0.9 mmHg; p = 0.230). In the third trimester, the difference between gestational hypertension and preeclampsia was significant for both variables (5.4 and 3.7 mmHg for systolic and diastolic blood pressure, respectively; p < 0.001). CONCLUSIONS: The differences in blood pressure between healthy and complicated pregnancies, which are observed as early as the first trimester of pregnancy, are detected when both systolic and diastolic blood pressure measurements in women with a late diagnosis of gestational hypertension or preeclampsia fall within accepted ranges of normotension. These differences offer new end points that may lead to an early identification of hypertensive complications in pregnancy as well as to the establishment of prophylactic interventions.

Adult↗

PubMed2003

Differences in circadian blood pressure variability during gestation between healthy and complicated pregnancies.

BACKGROUND: Changes in circadian variation of blood pressure (BP) could be used either to predict preeclampsia or to assess its severity. We examined and compared characteristics of circadian variability in BP in women with both healthy and complicated pregnancies who were systematically monitored throughout gestation. METHODS: We analyzed 2430 BP series sampled by ambulatory monitoring for 48 h once every 4 weeks from the first obstetric visit until delivery in 235 women with uncomplicated pregnancies, 128 with gestational hypertension, and 40 with preeclampsia. The circadian pattern of BP variation for each group and trimester of gestation was established by population multiple-components analysis. RESULTS: The differences in 24-h mean and amplitude between healthy and complicated pregnancies were highly significant in all trimesters (P < 0.001). Results further indicated similar circadian characteristics between gestational hypertension and preeclampsia in the first trimester of pregnancy. The difference between these two groups in 24-h mean was statistically significant for systolic (P =.002) and diastolic BP (P =.038) in the second trimester and, to a larger extent, in the third trimester (P < 0.001). CONCLUSIONS: The differences in BP between healthy and complicated pregnancies that can be observed as early as in the first trimester of pregnancy are found when both systolic and diastolic BP for women with a later diagnosis of gestational hypertension or preeclampsia are well within the accepted range of normotension. These differences offer new end points that may lead to an early identification of hypertensive complications in pregnancy as well as to the establishment of prophylactic intervention.

Adult↗

PubMed2003

Methods for comparison of parameters from longitudinal rhythmometric models with multiple components.

Multiple components linear least-squares methods have been proposed for the detection of periodic components in nonsinusoidal longitudinal time series. However, a proper test for comparison of parameters obtained from this method for two or more time series is not yet available. Accordingly, we propose two methods, one parametric and one nonparametric, to compare parameters from rhythmometric models with multiple components. The parametric method is based on techniques commonly and generally employed in linear regression analysis. The comparison of parameters among two or more time series is accomplished by the use of so-called dummy variables. The nonparametric method is based on bootstrap techniques. This approach basically tests if the difference in any given parameter obtained by fitting a model with the same periods to two different longitudinal time series differs from zero. This method calculates a confidence interval for the difference in the tested parameter. If this interval does not contain zero, it can be concluded that the parameters obtained from the two time series are different with high probability. An estimation of the p-value for the corresponding test can also be calculated. By the use of similar bootstrap techniques, confidence intervals can also be obtained for any parameter derived from the multiple component fit of several periods to nonsinusoidal longitudinal time series, including the orthophase (peak time), bathyphase (trough time), and global amplitude (difference between the maximum and the minimum) of the fitted model waveform. These methods represent a valuable tool for the comparison of rhythm parameters obtained by multiple component analysis, and they render this approach as a generally applicable one for waveform representation and detection of periodicities in nonsinusoidal, sparse, and noisy longitudinal time series sampled with either equidistant or unequidistant observations.

Blood Pressure↗

PubMed2002

Modeling the circadian variability of ambulatorily monitored blood pressure by multiple-component analysis.

The use of a set of new end points derived from ambulatory blood pressure monitoring (ABPM), in addition to the blood pressure (BP) values themselves, has been advocated to improve the sensitivity and specificity in diagnosing hypertension and to evaluate a person's response to treatment. An adequate estimation of rhythmic parameters depends, however, on the ability to describe properly the circadian pattern of BP variability. The purpose of this study was to identify a simple model that could characterize sufficiently well the circadian pattern of BP in normotensive healthy volunteers sampled by ambulatory monitoring. We studied 278 clinically healthy Spanish adults (184 men), 22.7 +/- 3.3 yr of age, without medical history of hypertension and mean BP from ambulatory profiles always below 135/85 mmHg for systolic/diastolic BP, who underwent sequential ABPM providing a total of 1115 series of BPs and heart rates (HRs), sampled on each occasion at 0.5h intervals for 48 h. Subjects were assessed while adhering to their usual diurnal activity and nocturnal sleep routine, without restrictions but avoiding the use of medication. The circadian rhythm in BP and HR for each subject was established by multiple-component analysis. A statistically significant 24h component is documented for 97% of the BP profiles, with a significant second (12h) harmonic documented in 65% of the profiles. Other ultradian harmonic components were significant in less than 20% of the profiles. A statistically significant increase in the coefficient of determination (percent of overall variability explained by the function fitted to the data) was only obtained after including the periods of 24 and 12 h for BP, and periods of 24, 12, and 6 h for HR in the model components. Although other ultradian components can be demonstrated as statistically significant in a small percent of subjects, a rather simple model including only the two first harmonics of the 24h period describes sufficiently well, at the specified sampling rate, the circadian pattern of BP in normotensive subjects. Departure from this model could characterize overt pathology, as recently demonstrated in the diagnosis of preeclampsia.

Adult↗

PubMed2002

The tolerance-hyperbaric test: a chronobiologic approach for improved diagnosis of hypertension.

Blood pressure (BP) displays predictable large-amplitude circadian variability. Thus, the identification and the proper definition of hypertension are highly ambiguous when based on single time-unspecified measurements. One way to deal with such variability in the diagnosis of hypertension is to replace the commonly used constant limits of BP by a time-specified reference interval based on the normal circadian BP rhythm assessed by ambulatory BP monitoring (ABPM). A proper reference limit can be constructed, for instance, as a tolerance interval computed for every specific time interval throughout the 24 h. Once such a threshold (given by the upper limit of the tolerance interval) is constructed, a hyperbaric index (HBI) can be computed by numerical integration of the total area of any given patient's BP profile above threshold. The HBI plus the duration of excess within the 24h day serves as nonparametric endpoints for assessing hypertension. Both retrospective and prospective evaluation of this tolerance-hyperbaric test validate its high sensitivity and specificity in the diagnosis of hypertension. We describe the theory of the HBI as well as a newly created dedicated software program that automatically derives the tolerance intervals from a reference database of normotensive subjects and calculates the HBI and other potentially valuable parameters based on data obtained by ABPM. The establishment of time-qualified tolerance limits and the assessment of the extent and timing of BP elevation represents a valuable tool for the more accurate diagnosis of hypertension as well as means of gauging response to treatment.

Adult↗

PubMedDate not supplied

[Sarcoidosis as an uncommon cause of articular pathology in pediatric patients].

We present two cases of sarcoidosis with chronic arthropathy presenting clinical and imaging findings compatible with chronic juvenile arthritis. One patient suffered from chronic nephropathy, with anomalous US pattern and sarcoid granulomas demonstrated at renal biopsy. Throughout the illness, the patient suffered from cutaneous lesions that proved to be sarcoid granulomas after biopsy. US and color-Doppler US were useful in detecting the lesions and in the follow-up of the chronic articular pathology in these children. Although sarcoidosis is uncommon, it is important to consider this disease in the diagnosis of chronic arthropathy in children. We analyze these two cases and comment on the clinical and imaging characteristics of pediatric articular sarcoidosis.

Arthritis, Juvenile↗