PubMed Health⌕ Search

Biomedical subjects

J Bejar

Publications and source records attributed to J Bejar.

At least 19 recordsLinked to original sources
PubMed2005

Do forceps biopsies truthfully reflect the nature of endoscopically uncovered polypoid lesions of the colon?

BACKGROUND: Total excision of colonic polyps is not always attainable and in some patients it is clinically contraindicated. Also, a resected polyp may be lost at any step between its endoscopic removal and its embedding in paraffin. The aim of this study was to compare the histological features of colonic polyps as analysed by the study of biopsy-forceps obtained samples with those assessed on scrutinizing the totally resected growths. PATIENTS AND METHODS: This prospective study included a cohort of 59 patients in whom, in the course of an elective colonoscopy, a total excision of a 6 mm-sized or larger polyp was called for. Sizeable biopsies were obtained by means of an Olympus Multibyte forceps prior to the total polypectomy. Subsequent to the study of the polypectomy specimens, the forceps biopsy samples were submitted for histological examination. The pathologists were blinded as to the source of the tissue they were studying. The diagnoses rendered by evaluating the biopsy samples and polypectomy specimens of each patient were contrasted with each other. RESULTS: Major discrepancies between the histological features of the fragments captured by the biopsy-forceps and the factual nature of the totally removed polyps were uncovered in 11 (18.6%) of 59 cases. Intriguingly, the grade of the tumours was underrated in all the 11 cases, as judged by contrasting the tentative diagnoses of the forceps-biopsies with the decisive diagnoses of the polypectomies. Importantly, 2 adenocarcinomas would have been missed by just looking at the forceps-retrieved sample. CONCLUSIONS: In our experience, a discordance of 18.6% is to be expected between the diagnoses rendered after examining forceps-biopsies of and totally excised colonic polyps. Nevertheless, it is advisable to procure biopsies prior to the excision of the growths, because on those occasions in which patients' growths cannot be removed or have not been retrieved for one reason or another, a small forceps-captured tissue sample correctly reflects the characteristics of the polyp in 81.4% of the cases. Finally, the biopsies may be discarded in the event that total removal was successful.

Adult↗
PubMed2004

Experimentally gained insight - based proposal apropos the treatment of osteonecrosis of the femoral head.

An impeded blood flow through the femoral head is incriminated in the etiopathogenesis of osteonecrosis of the femoral head. The disorder is either primary (idiopathic avascular osteonecrosis) or secondary to one condition or another, say, corticosteroid medication, fracture of the neck, coagulation defects, physical or thermal damage, storage disorders, alcoholism, and infectious, autoimmune as also marrow infiltrating diseases. In the wake of the necrosis, several mediators are released in increased amounts, prime among which is the vascular endothelial growth factor. The intermediates recruit endothelial progenitor cells, macrophages, osteoclasts, fibroblasts, and osteoblasts, which, pervading throughout the necrotic areas, initiate the reparative processes. The dead, soft and hard tissular debris is substituted by fibrous - later on by hematopoietic-fatty tissue - and bone. The newly formed, appositional and intramembranous bone is deficient in its mechanical properties. The ordinary load-carrying functions suffice to deform these weakened femoral heads so that osteoarthritic changes develop. Considering contemporary assumptions of the causes of osteonecrosis, oxygenation, revascularization, and core decompression are the realistic therapeutic interventions. Necrosis of rats' femoral heads is studied as a model of osteonecrosis in both adults and children. In view of rodents' lifelong persisting physeal cartilage, vascular deprivation-induced osteonecrosis in rats mimics children's Perthes disease. The experimental model, which is well suited to test treatment modalities, has been used to investigate the effects of exposure to hyperbaric oxygen with and without non-weight bearing, medication of enoxaparin, and creation of an intraosseous conduit on the remodeling of the avascular necrotic femoral head. Intriguingly, the shape of treated rats' femoral heads is disfigured to a greater degree than that of untreated animals. This is most likely due to the reduced yield strength and elastic modulus as well as the raised strain-to-failure of the recently formed bone making up the post-necrotic femoral heads. It follows that expedited osteogenesis is, counter intuition, detrimental to maintaining the hemispherical shape of the femoral head, and thus to an articulation with congruent load-bearing surfaces. If this is indeed the case, the remodeling of the necrotic femoral head should be delayed, rather than sped up, as the present day paradigm would have it. Bearing in mind that the dead osseous structures keep their mechanical attributes for quite a while, a slowed down new bone formation would favor the gradual replacement of the necrotic by living bone. Therefore, management of the adult patients with osteonecrosis and children with Perthes disease should focus on a slowly progressive substitution so that the decline of the bone's mechanical properties is kept to a minimum. One viable therapeutic mode is a medication of inhibitors of the vascular endothelial growth factor.

Animals↗
PubMed2001

Splenic littoral cell haemangioendothelioma: a new low-grade variant of malignant littoral cell tumour.

AIMS: Littoral cell angioma is a recently described splenic vascular tumour of splenic sinus lining cells. Almost all cases of splenic littoral cell tumours hitherto described were benign. METHODS AND RESULTS: A splenic littoral cell tumour recurred 8 years after splenectomy, with an abdominal mass and multiple liver metastases, resulting in the patient's death. Histologically, the original splenic tumour showed solid areas with small necrotic foci in addition to large areas of typical littoral cell angioma. The recurrent tumours showed increased solid architecture and slightly increased nuclear atypia. The tumours showed an immunohistochemical profile positive for factor VIII, CD31, CD68, cathepsin D, and CD21 and negative for CD34 and CD8, consistent with the immunophenotype of classic littoral cell angioma. Ki67 index in the recurrent tumours was higher than in the primary tumour. CONCLUSIONS: The mildly atypical, but not frankly malignant, histological features as well as the protracted clinical course support definition of the tumour as 'littoral cell haemangioendothelioma'. Low rate of Ki67 staining and diploid DNA histogram with low S-phase fraction of the tumours are in accordance with a low-grade malignancy. Literature review revealed two other cases of littoral cell tumours with disseminated disease that may be other examples of littoral cell haemangioendothelioma. Littoral cell haemangioendothelioma should be distinguished from the overtly malignant splenic angiosarcomas, of which a few may show splenic lining cell differentiation with some immunohistochemical features of littoral cells. Due to difficulties in predicting biological behaviour based on histological features of splenic littoral cell tumours, a long-term follow-up for these patients, especially for those with atypical histology, is recommended.

Antigens, CD↗
PubMed2000

Morphologic and morphometric study of patellar resurfacing with woven carbon filamentous pads.

Analysis of retrieved woven carbon filamentous pads, used for resurfacing of the patellar joint surface, disclosed a 4-zonal organizational pattern. Zone 1, facing the articular cavity, was devoid of carbon filaments and consisted of fibrous tissue. Foreign body granulation tissue and fibrous tissue occupied about one-third and approximately 50%-60% of the interfilamentous space in zones 2 and 3, respectively. Carbon filaments formed 2%-9% of zone 2 and 14%-16% of zone 3. An interfacial membrane-like zone 4 separated the carbon filamentous pads from a trabecular bony shell. The bone volume within the latter was approximately 25%. Given that the purpose of articular resurfacing with implants is repopulation of the defect by chondrocytes producing a cartilaginous matrix, the woven carbon filamentous pads did not fulfill this expectation. In an environment of an ongoing foreign body-induced granulomatous reaction, the stem cells permeating the interstices of the woven carbon filamentous pad are apparently incapable of maturing into highly differentiated cells (chondrocytes) synthesizing a highly complex (cartilaginous) matrix.

Adult↗
PubMed2000

Computer-assisted image analysis can aid the prognostication of advanced-stage neuroblastomas.

PURPOSE: The aim of this work was to detect nuclear parameters related to the prognosis of patients with stage III, IV or DS neuroblastomas. METHODS: Histological sections of 25 operation specimens obtained from children with advanced-stage neuroblastomas were subjected to computer-assisted image analysis. Statistical relationships between nuclear descriptors of the tumor cells and patients' clinical outcome were determined. RESULTS: The coefficient of variability of the mean nuclear area the mean nuclear elongation factor, and the mean nuclear averaged Feret diameter of the neuroblastoma cells were ascertained to be discriminators separating high-grade from low-grade tumors. CONCLUSIONS: The histomorphometrically gauged nuclear parameters may help oncologists to assess the prognosis of patients with advanced-stage neuroblastoma.

Adrenal Gland Neoplasms↗
PubMed2000

Pleomorphic hyalinizing angiectatic tumor of soft parts: immunohistochemical study including the expression of vascular endothelial growth factor.

We report morphologic, flow cytometric, and immunohistochemical findings in two cases of pleomorphic hyalinizing angiectatic tumor of soft parts. Both patients were middle-aged women with subcutaneous lesions located in the lower extremity. The tumors consisted of sheets of spindled and pleomorphic cells with frequent intranuclear pseudoinclusions associated with clusters of ectatic vessels surrounded by prominent perivascular hyaline material. Numerous, nonhyalinized vessels were also present, mostly in the peripheral areas of the lesions. Some of these vessels had their walls permeated by numerous small capillaries. Immunostaining for vascular endothelial growth factor (VEGF), a secreted protein that has been implicated in tumor-associated angiogenesis, demonstrated positive staining in both tumoral and endothelial cells. Tumor cells were also reactive to vimentin and CD34. Focal positivity for CD99 and factor XIIIa was also present. Flow cytometry yielded a diploid DNA histogram with S-phase fraction of 7%. Our findings corroborate those from previously reported cases. They further suggest that angiogenesis and the angiogenic factor VEGF may play a role in the development of this peculiar tumor.

12E7 Antigen↗
PubMed1999

Acute lipase-induced panniculitis in rats with ligated veins of the hindlimb: a contribution to the role of acute panniculitis as a precursor of lipodermatosclerosis of venous disease.

The authors studied the effect of ligation of the femoral and saphenous veins on the evolution of lipase injection-induced subcutaneous fibrosis and inflammation in the rats' hindlimbs. The superficial muscular fascia was thickened and the number of veins was increased 3 days and 3 weeks after vein ligation; both abnormalities disappeared 6 weeks postoperatively. Vein ligation did not quantitatively affect fascial thickening or fibrosing panniculitis in hindlimbs injected with lipase 6 weeks prior to sacrifice. The results contradict the proposition that lipase-induced injury of rats' subcutaneous tissues compromised by venous stasis may lead to a persistent chronic inflammation and fibrosis of the subcutaneous-fascial complex duplicating lipodermatosclerosis in man.

Acute Disease↗
PubMed1998

Comparative study of computer-assisted image analysis and light-microscopically determined estrogen receptor status of breast carcinomas.

BACKGROUND: Efficient tamoxifen treatment of breast cancer patients depends on the degree to which pathologists are consistently able to use the so-called "modified quickscore" method to differentiate between negative and low-grade positive scores based on the current four-grade scale of the estrogen receptor (ER) status of the tumors. OBJECTIVE: To quantitatively test pathologists' ability to adequately render correct readings of the ER status of breast tumors. METHODS: The ER status of breast carcinomas was estimated by two pathologists and measured by computer-supported analysis in sections stained with ER antibody by the immunoperoxidase technique. Levels of agreement between the examiners' semiquantification and histomorphometrically gauged measurements were compared statistically. RESULTS: The kappa coefficients were 0.28 on a case-by-case collation of the grades of nuclear staining, 0.52 on applying binary categories of positively versus negatively stained cell nuclei, and 0.89 using binary categories with a weighted score of 1.2 to separate ER-negative from ER-positive breast carcinomas. CONCLUSIONS: The findings suggest that an optimum rating system is achieved by assigning tumors with a weighted score of 1.2 or less to the ER-negative and those with a weighted score of 1.3 or more to the ER-positive category of breast carcinomas.

Breast Neoplasms↗
PubMed1997

The role of vimentin expression in predicting the long-term outcome of patients with localized renal cell carcinoma.

OBJECTIVE: To evaluate the prognostic significance of vimentin intermediary filament expression by tumour cells in patients with renal cell carcinoma (RCC) localized to the kidney. PATIENTS AND METHODS: Thirty-nine patients with localized RCC (pT1,pT2) were assessed in a retrospective study. Tumour cells were evaluated immunohistochemically for vimentin, epithelial membrane antigen (EMA) and polyclonal cytokeratin expression. The prognosis of cases expressing positive vimentin expression in tumour cells was compared with that of cases with no expression. Additional clinical information and conventional histological grade of the tumours were also included in the survival analysis. RESULTS: Univariate analysis of patient survival and tumour recurrence showed a statistically significant association between vimentin-positive tumours and poor patient outcome; the EMA stain showed borderline significance and histological grade was significantly associated with prognosis. The combination of tumour vimentin expression and histological grade provided a better predictor of prognosis and proved to be the best independent prognosticator of survival by multivariate analysis. CONCLUSIONS: Vimentin expression by tumour cells provides important prognostic information for patients with localized RCC; the combination of vimentin expression and histological grade is a better predictor for survival than grade or vimentin expression alone.

Carcinoma, Renal Cell↗
PubMed1996

Collecting duct carcinoma of kidney: a cytological study and case report.

An intraoperative cytological imprint of a well study case of collecting duct carcinoma of the kidney is reported. Papillary structures, fibrotic desmoplastic stroma, tubular formations, and tumoral cells with high grade cytological atypia were found. Cytological details described help to avoid misinterpretation of collecting duct carcinoma as a metastatic tumor. The peculiar morphology, the immunohistochemical and biological behavior of this rare tumor justifies its classification in a special group.

Humans↗
PubMed1996

A comparison between histological grade and nuclear morphometry for predicting the clinical outcome of localized renal cell carcinoma.

OBJECTIVES: To determine the interrelationship of histological grade and nuclear morphometry and to compare their prognostic significance in patients with localized renal cell carcinoma (RCC). PATIENTS AND METHODS: A retrospective prognostic study of 39 patients with localized (pT1, pT2) RCC was performed. Conventional histological grade and nuclear morphometry were assessed independently and the correlation between these grading systems and their impact on the patients' outcome were evaluated. RESULTS: Histological grade and the nuclear morphometric variables were significantly correlated: the strongest association was that between grade and the nuclear regularity factor. The best predictor of disease-free interval and survival (by univariate analysis) was the combination of nuclear area and nuclear elongation factor, followed by conventional tumour grade, nuclear elongation factor, nuclear regularity factor and nuclear area. However, a multivariate analysis showed that the only independent prognosticator for survival was the combination of nuclear area and nuclear elongation factor. CONCLUSIONS: This study indicates that nuclear morphometry is prognostically superior to histological grade in patients with localized RCC.

Carcinoma, Renal Cell↗
PubMed1996

Schistosomiasis as a cause of rectovaginal fistula: a brief case report.

A high rectovaginal fistula associated with schistosomiasis is reported in a 19-year-old Ethiopian woman. The case history is reviewed for clinical presentation, results of preoperative investigations, and operative and pathologic findings. Operative treatment consisted of a low anterior resection with division of the fistula and primary colorectal anastomosis. Histologic analysis confirmed that this rectovaginal fistula was caused by schistosomal eggs. Schistosomiasis is identified as a cause of high rectovaginal fistula, and may be managed effectively by low anterior resection.

Adult↗
PubMed1995

Brdu replication bands in the anguilliform fish Echelus myrus.

High-resolution replication banding patterns have been obtained in prometaphase and metaphase chromosomes of the anguilliform fish species Echelus myrus by treating kidney cell cultures with 5-bromodeoxyuridine during the mid-late synthesis phase. The results show the superiority of the in vitro technique in obtaining a higher number of bands which permit an accurate identification of all chromosome pairs. Different replication patterns were compared with C-bands and silver-stained nucleolus organizer regions, providing information on the replication order of different chromatin regions.

Animals↗
PubMed1994

Early prenatal diagnosis of polycystic pancreas with narrow thorax and short limb dwarfism.

We describe the ultrasound findings of polycystic pancreas with short rib dwarfism in the early second trimester. Radiologic, morphologic, and histologic examination after pregnancy termination confirmed the findings and also disclosed dysplastic kidneys. The skeletal anomalies are similar to those in Verma Naumoff type of short rib polydactyly, but the extraskeletal malformations have never been reported before in this syndrome.

Abnormalities, Multiple↗
PubMed1993

The difference between septated and nonseptated nuchal cystic hygroma in the early second trimester.

OBJECTIVE: To compare nonseptated and septated cystic hygromas in terms of morphologic appearance and prognosis. METHODS: During a 5-year period, 125 cases of nonseptated cystic hygroma were detected by transvaginal sonography among 7582 sonographic fetal scans (1.6%) in the first and early second trimesters. Twenty-five cases of septated cystic hygroma were detected in the same population. Fetal karyotype abnormalities; sonographic, morphologic, and histologic appearance; and pregnancy outcome were compared between the groups. RESULTS: Whereas 98% of the nonseptated cystic hygromas were transient, only 44% of the 25 septated cystic hygromas were transient. Six of the 106 cases of nonseptated cystic hygroma that underwent karyotyping were dyskaryotic (5.7%), compared with a 72% (18 of 25) aneuploidy rate in the septated cystic hygromas. Only two cases of hydrops fetalis (1.7%) occurred among the nonseptated cystic hygromas, versus 40% (ten of 25) in the septated cystic hygromas. Fifteen percent of the nonseptated cystic hygromas had associated anomalies (17 of 115) versus 52% (13 of 25) in the septated counterpart. As compared with the septated group, the nonseptated cystic hygromas had a different sonographic, morphologic, and histologic appearance. The live-birth rate was 94% (108 of 115) in the nonseptated cystic hygromas, versus only 12% in the septated group. CONCLUSIONS: This study confirms our previous suggestion that nonseptated cystic hygromas differ from septated lesions, not only in location and morphologic appearance, but also in prognosis.

Adult↗