Biomedical subjects

J Barba

Publications and source records attributed to J Barba.

At least 19 recordsLinked to original sources

PubMed1999

Combined surgical approach for sarcoma lung metastasis with atrial involvement.

A 20-year-old patient, who had been treated for a femur sarcoma with pulmonary metastases 8 years before, arrived at our institution with a new metastatic hilar lung nodule. During the standard lobectomy procedure an unexpected atrial invasion by the tumor was discovered. Intraoperative transesophageal echocardiography (TEE) showed a big pediculated tumor in the atrium. Cardiopulmonary bypass (CPB) was required in order to safely resect the atrial wall with the tumor. The atrial defect was repaired with a pericardial patch. Postoperative course was uneventful. After 14 months, the patient is asymptomatic and free of disease.

Adult↗

PubMed1998

A parametric fitting algorithm for segmentation of cell images.

This paper presents a parametric fitting algorithm for segmentation of cervical and breast cell images from cytology smears. A parametric elliptical model for cells is introduced and the parameters adjusted to fit the cell shapes while minimizing a cost function. Segmentation results of noisy human cervical cell and textured breast cell images demonstrate that the proposed parametric fitting algorithm is very successful in segmentation of images of both nonoverlapped and overlapped elliptically shaped cells.

Algorithms↗

PubMed1998

Long-term cardiac rehabilitation program favorably influences fibrinolysis and lipid concentrations in acute myocardial infarction.

BACKGROUND AND OBJECTIVE: The control of well-known atherosclerotic risk factors represents the optimal strategy in the prevention of acute coronary syndromes. It was the aim of this work to analyze the effects of a long-term cardiac rehabilitation program on the changes of fibrinolysis parameters and plasma lipid profile in coronary patients. DESIGN AND METHODS: The study was carried out in 30 (M/F:22/8, mean age 47 years) survivors of a first acute myocardial infarction (AMI) and in 30 healthy controls who underwent a cardiac rehabilitation program (9 months duration). Samples were taken before, at 3 and 9 months after the beginning of the program to measure: tissue-type plasminogen activator (t-PA) antigen and plasminogen activator inhibitor (PAI-1) activity and antigen. A lipid profile including cholesterol (both HDL and LDL) and lipoprotein(a) was also assessed. The Wilcoxon and Mann-Whitney tests were used for statistical comparisons. RESULTS: There was a marked decrease of functional PAI-1 after 3 and 9 months as compared with baseline in AMI patients (p < 0.01). Results showed a significant increase of HDL-cholesterol (p < 0.01) and decrease of lipoprotein(a) levels after the exercise program (p < 0.01). INTERPRETATION AND CONCLUSIONS: The cardiac rehabilitation program improved fibrinolysis, by reducing the functional levels of PAI-1, and ameliorated the lipid profile by decreasing lipoprotein(a) and increasing HDL-cholesterol in patients with AMI. A long-term cardiac rehabilitation has positive effects on some risk factors for coronary disease.

Acute Disease↗

PubMed1997

[Pericardial hematoma 2 years after coronary surgery].

Cardiac tamponade is a life-threatening complication after cardiac surgery which may develop in the early or late postoperative period. The latest have been defined arbitrarily as the ones occurring after the 7th postoperative day. They are less common than the early ones and most of the cases have been reported up to six months after the operation. They usually determine diagnostic difficulties that can negatively influence the prognosis. Because of its atypical late appearance, a case of a 65 year old man is presented who developed a postpericardiotomy syndrome and subsequently a pericardial clot nearly two years after aortocoronary bypass grafting.

Aged↗

PubMed1996

An iterative algorithm for cell segmentation using short-time Fourier transform.

In this paper, an iterative cell image segmentation algorithm using short-time Fourier transform magnitude vectors as class features is presented. The cluster centroids of the magnitude vectors are obtained by the K-means clustering method and used as representative class features. The initial image segmentation classifies only those image pixels whose surrounding closely matches a class centroid. The subsequent procedure iteratively classifies the remaining image pixels by combining their spatial distance from the regions already segmented and the similarities between their corresponding magnitude vectors and the cluster centroids. Experimental results of the proposed algorithm for segmenting real cell images are provided.

Algorithms↗

PubMed1996

[Myocardiopathies (XI). Restrictive myocardiopathy: concept, classification, and clinical approach].

Currently, cardiomyopathies are defined as "heart muscle diseases of unknown etiology". Restrictive cardiomyopathy is the rarest type of this disease, and the only one with no uniformly accepted diagnostic criteria. Its importance lies primarily in properly distinguishing it from constrictive pericarditis because of the direct consequences of mistakenly treating a case of constrictive pericarditis as if it were inoperable. Restrictive cardiomyopathy must be considered within the broader spectrum of diastolic dysfunction. Diagnostic criteria used show a general consensus for the diagnosis of restrictive cardiomyopathy in patients with clinical signs of heart failure in the presence of a nondilated, nonhypertrophic left ventricle with preserved contractility but abnormal diastolic function. Characteristically, right and left ventricular filling pressures are elevated and a dip and plateau diastolic pressure pattern appears. Restrictive cardiomyopathy may be either idiopathic and thus be a true cardiomyopathy in the strict sense of the term or secondary to an infiltrative disease of the myocardium. In this article we review the clinical and hemodynamic features of this disease and the different imaging techniques used in patients to help differentiate restrictive cardiomyopathy from constrictive pericarditis. Finally we study some types of restrictive cardiomyopathies.

Cardiac Catheterization↗

PubMed1994

Nuclear diffuseness as a measure of texture: definition and application to the computer-assisted diagnosis of parathyroid adenoma and carcinoma.

A measure of texture, the nuclear diffuseness, was formulated for use in biological classification, and specifically to characterize quantitatively chromatin texture. Nuclear diffuseness corresponds to the amount of local intensity variation in the digitized image of a nuclear profile. As a setting in which to test the efficacy of nuclear diffuseness as a diagnostic tool, the identification of parathyroid adenoma and carcinoma was considered. Digitized images of sections of parathyroid chief cell nuclei were obtained from 16 biopsies, and the nuclear diffuseness, as well as other morphometric descriptors, were computed. With just the average nuclear diffuseness and average nuclear profile area, jackknife (leave-one-out) classification using an artificial neural network was able to diagnose correctly and unambiguously the condition (normal, parathyroid adenoma, or parathyroid carcinoma) in 15 of 16 cases. In one case, the neural network assigned a higher weight to the correct diagnosis, but was unable to distinguish between normal and adenoma conclusively.

Adenoma↗

PubMed1994

[Dynamic cardiomyoplasty. Preliminary experience].

INTRODUCTION AND OBJECTIVES: The purpose of this study is to show our experience in clinical dynamic cardiomyoplasty. PATIENTS, MATERIALS AND METHODS: Six patients with end-stage heart failure and 2 patients with left ventricular aneurysm underwent dynamic cardiomyoplasty using the latissimus dorsi muscle. The latissimus dorsi was electrically conditioned before the procedure through a lead placed under local anesthesia and connected to an external cardiac pace-maker. Surgical technique--including dissection of the latissimus dorsi and encircling of the ventricles with the muscle flap--was performed in general terms as described at the Broussais Hospital. In the first 3 patients a bipolar lead connected to a single impulse generator was used. In the other 5 patients a train of impulses cardiomyostimulator was used. Changes in systolic function were studied through Doppler-echocardiography and radionuclide studies. Changes in diastolic function were evaluated through E wave velocity and deceleration time. RESULTS: Mean follow up was 9 +/- 5.7 months. No early deaths were recorded. One patient underwent emergency surgery, one week after the procedure, because of a tear of the patch used to close the wall defect after left ventricular aneurysm resection. In 2 patients a subcutaneous serous collection secondary to muscle dissection was evacuated. One patient died due to a stroke 4 months after the procedure. Another patient died after an unsuccessful coronary transluminal percutaneous angioplasty 11 months after the procedure. An improved functional class was observed in all patients. No changes in systolic function were observed after surgery when the cardiomyoestimulator was turned-off either with echocardiography (26.7 +/- 8.6 vs 24.8 +/- 5.8% [NS]) or radionuclides (24.5 +/- 9.5 vs 20.2 +/- 8.3% [NS]). When the cardiomyostimulator was turned-on a statistically significant increase of the left ventricular ejection fraction was observed either with echocardiography (24.8 +/- 5.8 vs 37 +/- 10.3%; p < 0.05) or radionuclides (20.2 +/- 8.3 vs 33.3 +/- 12.2%; p < 0.05). This significant increase of the ejection fraction has been observed in subsequent studies. Nevertheless the differences when the cardiomyostimulator is turned-on and turned-off have decreased several months after the procedure. A significant increase of the left ventricular outflow velocity (cm/seg) was observed when the generator was turned-on (57.7 +/- 20.4 vs 75.1 +/- 17.8%; p < 0.01). A significant increase of the dP/dt (mmHg/seg) was observed when the generator was turned-on (706.3 +/- 291.5 vs 592.6 +/- 181.6%; [NS]). No significant changes were observed on E wave velocity. A significant decrease of the deceleration time was observed several months after the procedure (p < 0.05). CONCLUSIONS: We believe that dynamic cardiomyoplasty is a safe and valid surgical procedure for some patients with end stage cardiomyopathies as well as in association with Jatene's technique for the management of left ventricular aneurysms. An improvement in functional class is present and a significant increase of the left ventricular systolic function. Nevertheless it is necessary to find new systolic parameters, independent of volumetric calculations, to evaluate the mechanical support of the muscle as well as to determine the long-term pattern of electrical stimulation.

Adult↗

PubMed1993

Ovarian dysplasia: nuclear texture analysis.

BACKGROUND: Ovarian dysplasia has been defined by histologic and morphometric studies focusing on architectural and nuclear profile changes. A new technique is used to enhance the accuracy of this diagnosis by a quantitative evaluation of the nuclear texture that represents the nuclear chromatin pattern on which conventional diagnoses of malignancy are usually made. METHODS: Histologic sections from 35 ovaries classified as malignant (12), dysplastic (12), and normal (11) were evaluated by tracing boundaries of nuclear profiles and measuring "textons" (texture primitives) with a histogram analysis of three zones of gray level densities (called for simplification white, gray, and dark). The average combined area was tabulated for specimens with the same diagnosis, and linear regression plots compared the texton area with total nuclear area. RESULTS: The dimensions of textons originally hidden inside the chromatin and revealed by histograms were found to be closely clustered in normal epithelium, and increasingly dissociated from the containing nucleus as the lesion progressed from dysplastic to malignant. The statistical multivariate analysis including nine parameters correctly classified the three diagnostic categories as normal, dysplastic, and malignant. CONCLUSIONS: Computerized image analysis of nuclear texture adds accuracy to the recently elaborated morphometric methods to define ovarian dysplasia, a potential precursor of ovarian carcinoma.

Cell Nucleus↗

PubMed1993

[Correction of transposition of great vessels with and without associated congenital defects. Description of two clinical cases].

We describe two cases of corrected transposition of great vessel (L Transposition). The first case was diagnosed in a man of 70 years old and was not associated with other congenital defects. The second case regards a young man of 16 years old and congenital cardiopathy was associated with interventricular defect and left Ebstein disease. We discuss the different evolution of L Transposition according to the presence or not of other congenital defects and we analyse right ventricle behaviour when it is submitted systemic pressure. In the literature only 26 cases of L Transposition were described in patients over 40 years old. The first case represents a rarity and it shows how in the absence of associated congenital defects, the right ventricle is able to adapt to systemic pressure. Bidimensional echocardiography in the method of choice to diagnose and evaluate congenital cardiopathy in adult age.

Abnormalities, Multiple↗

PubMed1993

Morphometric analysis of benign and malignant adrenal pheochromocytomas.

At present, there are no reliable histologic features that can predict malignancy in adrenal pheochromocytomas other than the documentation of metastases. With the use of computerized interactive morphometry, our aim was to assess nuclei from tissue sections of confirmed cases of benign and malignant pheochromocytomas to determine whether consistent quantitative differences existed between the two. Eight benign cases with at least a 5-year follow-up and nine malignant cases with documented metastases were evaluated. Size distribution plots of the maximum nuclear cord length and of the nuclear area showed a narrow peak for the malignant cases, whereas benign cases showed a right-shifted curve with a wider peak. We concluded that nuclear morphometric analysis of benign and malignant pheochromocytomas yields two distinctive patterns and may be of utility in the assessment of future cases.

Adrenal Gland Neoplasms↗

PubMed1992

Quantitative perimeter and area measurements of digital images.

Quantitative estimations of perimeter and area from digitized video images, and the application of these features in morphometry, are discussed. Estimations from manual tracings via interactive peripherals and from chain codes are addressed. Topics discussed are calibration, determination of vertical and horizontal pixel resolution, effects of tracing jitter, and for chain codes, the spatial quantization scheme representation of the digital contour. Finally, new perimeter estimators for 4-connected and 8-connected chain codes for non-unity pixel aspect ratio are presented with simulation results.

Animals↗

PubMed1992

Breast cancer. Importance of adequate surgical excision prior to radiotherapy in the local control of breast cancer in patients treated conservatively.

The extent of excision performed for mammary carcinoma prior to radiotherapy as a risk factor for local recurrence was studied in 503 patients. Three hundred twenty-three tumors (62%) were excised with a minimal rim of tissue (tumorectomy). One hundred forty-two patients (27%) had wide excision and 56 (11%) had quadrantectomy. Tumor stage, size, and radiation treatment were similar for all groups. Forty-one percent of tumorectomies had involved margins, and only 14% and 7% were involved in the wide excision and quadrantectomy groups, respectively. Local failure was 15% for tumorectomy, 7% for wide excision, and 5% for quadrantectomy. In T1 ductal carcinoma, only 4% of those with excisions greater than 5 cm had recurrences. Lesser excision had 20% recurrence. Extent of excision before radiotherapy is an important risk factor for recurrence. Failure was inversely proportional to the amount of breast tissue resected. Narrow excision should be discouraged since a larger tumor burden remains that may not be sterilized by radiation.

Adult↗

PubMed1992

Cell contour extraction on multi-threshold images.

A procedure for the extraction of cell and nuclear contours from digital images is presented. The procedure is simple and suitable for efficient implementation in an interactive environment where the user selects a region of interest containing the cell to be segmented. Segmentation is facilitated by multi-thresholding where the threshold values are determined by an iterative algorithm using the mean square error criteria to cluster the image pixel values. Edges are detected on the threshold images by employing a binary morphological filter and the desired contours are selected by considering closed contours in the edge image. The cell region is first extracted by performing segmentation, edge detection and contour extraction on the region of interest. The nuclear region is subsequently extracted by reapplication of the algorithms within the extracted cell region. Segmentation examples are presented.

Algorithms↗

PubMed1992

Echocardiographic follow-up of right atrial tumoral invasion by hepatocarcinoma: a case report.

Hepatocellular carcinoma is known for its tendency to grow in the venous system. We describe a patient suffering from hepatocellular carcinoma with right atrial metastatic tumor. Echocardiography demonstrated a right atrial mass as a result of invasion of the inferior vena cava and next extension into right atrium. The autopsy showed an irregular polypoid mass that occupied the entire right and left atrium, hepatocarcinoma was confirmed by histologic studies. We advocate performing echocardiographic examination in patients with hepatocarcinoma who have cardiac symptoms and signs.

Adult↗

PubMed1992

Dynamic cardiomyoplasty in a patient with end-stage cardiomyopathy.

Dynamic cardiomyoplasty is a relatively new surgical procedure by which a transformed fatigue-resistant skeletal muscle wrapped around the heart is stimulated to contract in synchrony with it, thereby augmenting the ventricular functions of a failing heart. We performed a cardiomyoplasty with latissimus dorsii (LD) in a patient who was refused the heart transplant programme because of pulmonary hypertension and psychosocial contraindications. The patient was 34 years old, functional class grade IV of the New York Heart Association (NYHA), with a three-month history, due to ischemic cardiomyopathy with multiple vessels affected, 10% ejection fraction, arteriolar pulmonary resistance of 7.5 U Wood. Cardiomyoplasty was performed after training the LD muscle for four weeks. One week later the pacemaker was programmed in a DDD mode: amplitude 3.75 V, pulse duration 0.50 ms, AV delay 175 ms. The patient reached functional class grade I-II (NYHA). Inotrope support was discontinued and great clinical improvement was noted. The ejection fraction rose from 10% to 30%. Echocardiographic left ventricular outflow tract velocity increased from 0.33 m/s to 0.60 m/s. These values were compared with radionuclide angiocardiography and echocardiography evaluations. The great clinical improvement and positive changes in left ventricular parameters suggest that cardiomyoplasty is useful in the treatment of some cases of dilated or ischemic cardiomyopathy as an alternative to heart transplantation. Long term follow-up is necessary to evaluate this procedure.

Adult↗

PubMed1992

[Changes in diastolic function in heart rejection: role of Doppler echocardiography].

In acute cardiac rejection, left ventricular diastolic function is altered. To study these abnormalities and their utility in cardiac allograft rejection, we studied 56 cardiac transplant recipients. All patients were assessed with endomyocardial biopsy and Doppler echocardiography done in the same day. A total of 163 Doppler studies were recollected. Cardiac transplant recipients were excluded during the early 6 weeks postoperative period. Totally, 100 biopsies were normal, 48 positive for mild rejection (Billingham Gde I-II) and 15 positive for moderate or severe rejection (Billingham Gde III-IV). Compared to negative biopsies, during acute rejection left ventricular wald thickness significantly increased (p < 0.05); isovolumic relaxation period and pressure half-time significantly decreased (p < 0.05, p < 0.001 respectively). Nevertheless, increase in peak early mitral flow velocity was only significantly associated with severe rejection (p < 0.001). Correlating only progressive shortening of isovolumic relaxation period parameter in the diagnosis of graft rejection, we forward a high sensibility (85%) and low specificity (57%). Thus, Doppler echocardiographic evaluation of left ventricular diastolic function provides a non-invasive tool for early detection of acute rejection monitoring after the early postoperative period.

Adult↗

PubMed1992

Use of computerized interactive morphometry in the diagnosis of mammary adenoma and adenocarcinoma in dogs.

We attempted to define quantitative objective criteria for diagnosis of mammary adenoma and adenocarcinoma in dogs. To that end, correlation between diagnosis made by conventional histologic examination and morphometric descriptors, obtained by computerized histologic analysis, was assessed in biopsy specimens of mammary tissue from 63 dogs. We used 2 interactive computer procedures: one assessed mean nuclear perimeter, mean nuclear area, and circularity factor; and the other evaluated nuclear stratification and cell crowding. A data base was generated with 11 specimens from normal mammary tissue, 17 specimens from mammary adenoma, 18 specimens from low-grade mammary adenocarcinoma, and 15 specimens from mammary adenocarcinoma. The mean values of nuclear perimeter, nuclear area, nuclei per millimeter of basement membrane, and minimal distances from cells to basement membrane gradually increased from normal to high-grade malignancy. Distributions of nuclear areas and of minimal distances from cells to basement membrane were shifted in specimens from malignant tumors. Multivariate analysis confirmed the homogeneity of the diagnostic groups.

Adenocarcinoma↗