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Biomedical subjects

J Prat

Publications and source records attributed to J Prat.

At least 73 records · Page 4Linked to original sources
PubMed1997

Primary angiosarcoma of the ovary: a report of seven cases and review of the literature.

Seven primary ovarian angiosarcomas were diagnosed in 7 patients 20 to 32 (mean 26) years of age. The most common clinical presentation was abdominal pain and distention. Three tumors were in the right ovary and 3 in the left; one was bilateral. Four tumors were Stage I and 3 Stage III. The tumors were brown and hemorrhagic, ranging in maximum dimension from 6 to 13 (average 10) cm. Microscopically, 5 tumors were pure angiosarcomas and 2 were associated with a dermoid cyst. Follow-up information ranging from 2 months to 9 (average 3.6) years was available for 5 patients. Three patients, all with Stage III disease, died of tumor (1 with a pure angiosarcoma, 2 with tumors arising in a dermoid cyst) 2, 15, and 30 months postoperatively. Two patients with Stage I disease and follow-up data were alive and healthy 5.5 and 9 years postoperatively. The differential diagnosis of these tumors is discussed and the literature reviewed.

Adult↗
PubMed1997

Stability study of epirubicin in NaCl 0.9% injection.

OBJECTIVE: To determine the stability of epirubicin in NaCl 0.9% injection under hospital storage conditions. METHODS: NaCl 0.9% solution was added to epirubicin lyophilized powder to make a final concentration of 1 mg/mL to study the degradation kinetics and 2 mg/mL to study the stability in polypropylene syringes under hospital conditions. SETTING: Physical chemistry laboratory, Unitat de Fisicoquímica, Universitat de Barcelona. MAIN OUTCOME MEASURES: Solutions of epirubicin at 2 mg/mL in NaCl 0.9% solutions stored in plastic syringes were studied under hospital conditions at room temperature (25 +/- 1 degrees C) and under refrigeration (4 +/- 1 degrees C) both protected from light and exposed to room light (approximately 50 lumens/m2). All samples were studied in triplicate and epirubicin concentrations were obtained periodically throughout each storage/time condition via a specific stability-indicating HPLC method. To determine the degradation kinetics, solutions of epirubicin in NaCl 0.9% at 1 mg/mL were stored at different temperatures (40, 50, and 60 degrees C) to obtain the rate degradation constant and the shelf life at room temperature and under refrigeration. RESULTS: The degradation of epirubicin in NaCl 0.9% solutions follows first-order kinetics. The shelf life was defined as the time by which the epirubicin concentration had decreased by 10% from the initial concentration. In this study, epirubicin was stable in NaCl 0.9% injection stored in polypropylene containers for all time periods and all conditions. That results in a shelf life of at least 14 and 180 days at 25 and 4 degrees C, respectively. The maximum decrease in epirubicin concentration observed at 25 degrees C and 14 days was 4%, and at 4 degrees C and 180 days was 8%. The predicted shelf life obtained from the Arrhenius equation was 72.9 +/- 0.2 and 3070 +/- 15 days at 25 and 4 degrees C, respectively, in both dark and illuminated conditions. CONCLUSIONS: Solutions of epirubicin in NaCl 0.9% at 2 mg/mL are chemically stable when they are stored in polypropylene syringes under hospital storage conditions. No special precaution is necessary to protect epirubicin solutions (2 mg/mL) from light.

Antibiotics, Antineoplastic↗
PubMed1997

Optimisation of the prescription for trans-tibial (TT) amputees.

The great diversity of prosthetic mechanisms available nowadays leads to the question of which type of artificial foot would be the most advisable for a particular person. To answer correctly, it is necessary to establish, in an objective way, the performance of each type of prosthetic mechanism. This knowledge is obtained by means of the study of the subject-prosthesis interaction, both in static and dynamic conditions. This paper, based on the analysis of 8 trans-tibial (TT) amputees, presents a quantitative method for the study of human gait which allows the determination of the influence of four different prosthetic ankle-foot mechanisms (SACH, Single-axis, Greissinger and Dynamic) on gait. To do this, 1341 gait trials at different cadences were analysed (383 with normal subjects and 958 with amputees, using the four prosthetic feet under study). From all the variables available for study only those which offered interpretable clinical information were chosen for analysis. A total of 18 variables (kinetic, kinematic and time-related) were selected. A covariance analysis (ANOVA) of these variables was made, which showed that the factors influencing TT amputee gait were, in order of importance, cadence and leg studied (sound or prosthetic), inter-individual variability and, finally, the prosthetic mechanism used. When looking at the performance during gait of the 4 prosthetic mechanisms studied it can be observed that there are similarities in the kinetic study between SACH and Dynamic feet on one hand and Single-axis and Greissinger feet on the other. These results seem to support the classification criteria of articulated and non-articulated prosthetic mechanisms.

Adult↗
PubMed1997

Serous borderline tumors of the ovary.

The distinction of borderline tumors from invasive carcinomas is one of the commonest problems in ovarian tumor pathology. The borderline tumors are characterized by absence of destructive stromal invasion although they can implant on peritoneal surfaces. The implants may in turn invade the underlying tissue. Serous borderline tumors (SBTs) account for one-quarter to one-third of malignant serous tumors. Mostly, they are confined to the ovary (Stage 1), whereas in some cases they spread within the pelvis (Stage 2) or upper abdomen (Stage 3). As recently shown, typical SBTs may contain foci of microinvasion, a finding that does not appear to influence the prognosis. SBTs are associated with peritoneal implants in about 30% of cases. Peritoneal implants most often appear similar to the primary ovarian tumor, although they could show more or less atypia than the primary tumor. The peritoneal implants of SBTs have been classified into non-invasive and invasive categories. Recently, some studies showed that in SBTs associated with peritoneal implants, separation of the implants into invasive and non-invasive categories has important prognostic implications. Furthermore, severe nuclear atypia and mitotic activity in the implants are independently related with a poor prognosis. In addition, these studies suggest that chemotherapy is appropriate only for patients with invasive implants without taking into account lymph node status. Finally, it has recently been established that tumors with a morphology identical to that of SBTs may arise as primary tumors of the peritoneum with absent or minimal involvement of ovarian surfaces.

Journal Article↗
PubMed1997

Prognostic value of S-phase fraction in lymph-node-negative breast cancer by image and flow cytometric analysis.

Cellular DNA content and proliferation rates have been suggested as prognostic factors in breast carcinomas. A series of 271 lymph-node negative breast carcinoma patients without adjuvant therapy was reviewed (mean follow-up, 108 mo). Tumor cells from the same paraffin-embedded block tissue (Hedley's method) were analyzed by image analysis (IA) in Feulgen-stained smears and by flow cytometric analysis (FC). Clinicopathologic features, ploidy, S-phase fraction, and percentage of tumor cells with more than 5n DNA content (in diploid tumors, by IA) were related to outcome. The results of IA and FC were compared in 115 cases. Tumor size, histologic grade, desmoplasia and S-phase fraction were significant predictors of survival in multivariate analysis (Cox proportionate regression) (P < or = 0.03). Ploidy by the two methods showed agreement in 100 carcinomas (87%). Of the 15 discordant cases, FC detected 6 multiploid and 4 aneuploid-peridiploid. In contrast, IA detected more tetraploid carcinomas. Tumor size, histologic grade, desmoplasia, and S-phase fraction were independent predictors of long-term prognosis in our patients. Ploidy and percentage of tumor cells with more than 5n DNA content were not prognostic indicators. FC detected aneuploidy more frequently than did IA.

Adult↗
PubMed1997

Clear cell tumors of the female genital tract.

Clear cell adenocarcinomas of the vagina, cervix, endometrium, and ovaries show very similar histological features. Several other tumors and tumor-like lesions of the female genital tract may also contain clear cells and may occasionally be misinterpreted as clear cell adenocarcinomas. These conditions include microglandular hyperplasia, mesonephric hyperplasia, Arias-Stella change, smooth muscle tumors containing clear cells, dysgerminoma, yolk sac tumor, metastatic renal cell carcinoma, steroid cell tumors, hepatoid carcinomas, signet-ring-cell stromal tumors, and trophoblastic tumors. This review discusses the histological features of all of these lesions, emphasizing the morphological aspects that are essential to accurate differential diagnosis.

Adenocarcinoma, Clear Cell↗
PubMed1996

Low fatty acid unsaturation protects against lipid peroxidation in liver mitochondria from long-lived species: the pigeon and human case.

Birds have a much higher maximum longevity (MLSP) than mammals of similar metabolic rate. Recent data showed that pigeon mitochondria produce oxygen radicals at a rate much slower than rat mitochondria, in spite of showing similar levels of oxygen consumption (Free Rad. Res., 21 (1994) 317-328). Since oxidative damage from and to mitochondria seems important in relation to aging and longevity, and mitochondrial membranes are situated at the place where oxygen radicals are generated, we studied protein and lipid peroxidation and fatty acid composition of the three main membrane phospholipids of liver mitochondria from rats (MLSP = 4 years) and pigeons (MLSP = 35 years). It was found that pigeon mitochondria show lower levels of fatty acid unsaturation than rat mitochondria in the three lipid fractions, mainly due to a substitution of highly unsaturated fatty acids (20:4 and 22:6) by linoleic acid (18:2), and that these mitochondria are more resistant to lipid peroxidation. Previous research has also obtained exactly the same major difference in fatty acid composition in human mitochondria when compared to those of rat. Thus, present information suggests that the liver mitochondrial membranes of especially long-lived species show both a low level of free radical production and a low degree of fatty acid unsaturation as important constitutive protective traits to slow down aging.

Animals↗
PubMed1996

Epithelioid haemangioma of the heart.

The authors report a case of epithelioid haemangioma (EH) of the right atrium, the first description of this tumour originating in the heart. The lesion was found incidentally during a cardiac echocardiogram and diagnosed pre-operatively as cardiac myxoma. The tumour must be differentiated from the exceptionally rare epithelioid haemangioendothelioma (EHE) of the heart and from a cardiac myxoma. A correct pathological diagnosis is clinically important since EH is a benign tumour, whereas EHE and cardiac myxoma can recur and metastasize. The uneventful follow-up of this patient confirms the benign nature of EH.

Diagnosis, Differential↗
PubMed1996

Effect of dietary vitamin E levels on fatty acid profiles and nonenzymatic lipid peroxidation in the guinea pig liver.

Guinea pigs were fed for five weeks with three diets containing different levels of vitamin E: LOW (but nondeficient, 15 mg of vitamin E/kg diet), MEDIUM (150 mg/kg diet), and HIGH (1,500 mg/kg diet). Dietary vitamin E supplementation did not change oxidative stress indicators in the hydrophilic compartment but increased liver alpha-tocopherol in a dose-dependent way and strongly decreased sensitivity to nonenzymatic in vitro liver lipid peroxidation. This last effect was already observed in group MEDIUM, and no further decrease in in vitro lipid peroxidation occurred from group MEDIUM to group HIGH. The protective effect of vitamin E against in vitro lipid peroxidation was observed even though an optimum dietary concentration of vitamin C for this animal model was present in the three different vitamin E diets. Both HIGH and LOW vitamin E decreased percentage fatty acid unsaturation in all phospholipid fractions from membrane origin in relation to group MEDIUM. The results, together with previous information, show that both vitamin E and vitamin C at intermediate concentrations are needed for optimal protection against lipid peroxidation and loss of fatty acid unsaturation even in normal nonstressful conditions. These protective concentrations are higher than those needed to avoid deficiency syndromes.

Animals↗
PubMed1996

p53 in a thyroid follicular carcinoma with foci of poorly differentiated and anaplastic carcinoma.

The clinical and pathologic features of a rare case of follicular carcinoma with small foci of poorly differentiated and anaplastic carcinoma are presented. Eight years after the removal of the primary neoplasm, the patient developed pulmonary and brain metastases that were predominantly composed of the poorly differentiated and anaplastic components. A comparative immunohistochemical and molecular analysis of p53 status in the follicular, poorly differentiated and anaplastic components of the tumor was performed. p53 immunostaining was restricted to the poorly differentiated and anaplastic areas. Single strand conformation polymorphism analysis (SSCP-PCR) from DNA obtained by microdissection demonstrated the presence of a mutation (TAT-->TGT; Tyr-->Cys) in codon 220, exon six of the p53 gene in the anaplastic component, that was absent in the well-differentiated follicular areas. The results of that study in this rare tumor support that p53 has a tumor progression role in thyroid tumorigenesis.

Adenocarcinoma, Follicular↗
PubMed1996

Synchronous mucinous tumors of the appendix and the ovary associated with pseudomyxoma peritonei. A clinicopathologic study of six cases with comparative analysis of c-Ki-ras mutations.

Mucinous tumors of the ovary are often associated with mucinous tumors of the appendix. It has not been clearly determined whether they are independent or metastatic neoplasms. A clinicopathologic study and a comparative analysis of c-Ki-ras mutations were done in six cases of synchronous ovarian and appendiceal tumors. The clinicopathologic features (simultaneous presentation, bilaterality or right-sided predominance, similar histopathologic findings, presence of pseudomyxoma peritonei) suggested that they were primary appendiceal tumors metastatic to the ovaries. DNA was extracted from formalin-fixed, paraffin-embedded tissue, and target sequences were amplified in vitro by the polymerase chain reaction. Mutations were detected by the presence of restriction fragment length polymorphism, artificially introduced by the use of mutant amplimers. The pattern of c-Ki-ras mutations was identical in the ovarian and appendiceal tumors of all patients. Four patients had a GGT --> GAT (Gly --> Asp) transition and one a GGT --> GTT (Gly --> Val) transversion, all detected in codon 12. No mutation was found in the sixth patient in either the ovarian or the appendiceal tumor. Because c-Ki-ras mutations are considered to represent an early event in tumorigenesis, our results support a clonal nature for both tumors and suggest that they are not independent tumors but rather originate one from another.

Adenocarcinoma, Mucinous↗
PubMed1996

72-kilodalton type IV collagenase, type IV collagen, and Ki 67 antigen in serous tumors or the ovary: a clinicopathologic, immunohistochemical, and Serological study.

The immunohistochemical expression of 72-kDa type IV collagenase [matrix-metalloproteinase (MMP)-21], basement membrane component type IV collagen and proliferation-related antigen Ki 67 were investigated in 43 benign, borderline, and malignant serous tumors of the ovary. The results were compared with the histotypes of ovarian serous tumors and with their clinical behavior. Serum evaluation of MMP-2 was performed in 14 patients with cystadenocarcinoma and the data compared with that of a control group. The basement membrane (BM) was continuous in benign cystadenomas and in some borderline tumors, whereas it was discontinuous or absent in other borderline tumors, in borderline tumors with microinvasion, and cystadenocarcinomas. The percentage of MMP-2- and Ki 67-expressing cells increased from cystadenomas to borderline tumors, being the highest in malignant tumors; a frequent basal disposition of the MMP-2 cytoplasmic granules also was observed in cystadenocarcinomas. Statistical analysis demonstrated that MMP-2 expression was inversely related to BM integrity. Serum MMP-2 values did not differ from that of the control group. Cox regression analysis showed that tumor stage and grade were significant prognostic factors, whereas MMP-2 and Ki 67 immunohistochemical expression added no further significant information to the prognosis. The investigators conclude that the correlation between increasing MMP-2 expression and BM alteration gives support to the hypothesis of a direct role of the metalloproteinase in the process of destructive stromal invasion. MMP-2, type IV collagen, and Ki 67 immunodetection varied according to the histologic classification of ovarian serous tumors. However, neither these factors nor the serum evaluation of MMP-2 appear useful as prognostic predictors in this series.

Antibodies, Monoclonal↗
PubMed1996

Ras oncogene mutations in thyroid tumors: polymerase chain reaction-restriction-fragment-length polymorphism analysis from paraffin-embedded tissues.

Ras mutations have been found in thyroid lesions. Different studies have shown different frequencies of mutations among benign and malignant lesions. The presence of point mutations in codons 12 and 13 of the c-K-ras, c-H-ras, and N-ras genes was studied in 58 thyroid lesions (10 nodular goiters, 10 follicular adenomas, and 15 papillary, 10 follicular, and 13 anaplastic carcinomas). DNA was extracted from formalin-fixed paraffin-embedded tissue, and target sequences were amplified in vitro by the polymerase chain reaction. Mutations were detected by the presence of restriction-fragment-length polymorphisms either occurring naturally or introduced artificially by the use of mutant primers. No characterization of the mutations was performed. Results were correlated with clinicopathologic features and patient follow-up. One goiter showed a mutation at codon 13, c-K-ras. All follicular adenomas, including three hyalinizing trabecular adenomas, were negative. Four papillary carcinomas presented mutations (one at codon 13, c-K-ras; three at codon 12, N-ras). Two follicular carcinomas showed mutations at codon 12, N-ras. Five anaplastic carcinomas showed mutations (two at codon 12 and two at codon 13, c-K-ras; one at codon 12, N-ras). In summary, the results confirm that ras oncogenes play a role in thyroid tumorigenesis, probably at an early step. Ras mutations appear not to be related to prognosis.

Adenoma↗
PubMed1996

Sex-steroid hormone receptors in human medullary thyroid carcinoma.

Three complementary techniques were used to detect sex-steroid hormone receptors in tumor tissues from seven patients with medullary thyroid carcinoma: steroid binding analysis, enzyme immune assay, and immunohistochemistry. The presence of estrogen receptors was detected by steroid binding analysis in one of seven patients, although in very low concentrations (3.17 to 5.06 fmol/mg protein). These results were confirmed by enzyme immune assay (6.35 to 9.32 fmol/mg protein). Progesterone receptors were found in five of seven patients by steroid binding analysis (11.1 to 47.9 fmol/mg protein), and progesterone receptor results were confirmed by enzyme immune assay (8.1 to 34.1 fmol/mg protein). By immunohistochemistry, progesterone receptors were focally detected in all cases, whereas all tumors were negative for estrogen receptors. In summary, our results confirm the presence of sex-steroid hormone receptors, particularly progesterone receptors in medullary thyroid carcinoma. The presence of progesterone receptors in medullary thyroid carcinoma apparently does not require the continuous presence of estrogen receptors.

Adolescent↗
PubMed1995

Evidence for the Maillard reaction in rat lung collagen and its relationship with solubility and age.

This study investigated age-related changes in collagen solubility and collagen-linked fluorescence, and their relationship with the Maillard reaction. As a result of the collagen purification of rat lung samples, we obtained two pools of collagen with different degrees of solubility. The relative distribution of collagen between these two fractions was time-dependent, and the proportion of the smaller and less soluble fraction increased with time (r = 0.73, P < 0.0001). In this fraction, the intensity of fluorescence at Exc 335 nm/Em 385 nm, and the total amount of pentosidine increased with age (r = 0.66, P < 0.002, and r = 0.69, P < 0.01, respectively). The mean values for fluorescence and pentosidine per milligram of collagen were, respectively, six and ten times greater in the less soluble fraction. In this fraction the pentosidine per milligram of collagen increased with age (r = 0.59, P < 0.03). Our results demonstrated the presence of pentosidine in rat lung collagen. Moreover, its accumulation in the less soluble fraction suggested a relationship between Maillard reaction products, physico-chemical changes in collagen solubility, and the ageing process in rat lungs.

Aging↗
PubMed1995

Expression of the ret proto-oncogene in phaeochromocytoma. An in situ hybridization and northern blot study.

The expression and distribution of ret proto-oncogene mRNA were investigated in five phaeochromocytomas of both familial and sporadic types by in situ hybridization (ISH) using digoxigenin-labelled cRNA probes and Northern blot (NB) analysis with random priming labelled cDNA probes. The probes corresponded to the tyrosine kinase domain of the gene. An excellent correlation was found between the ISH and NB results. By both techniques, the expression of the ret proto-oncogene was detected in three of the five cases, two of four familial tumours, and the only sporadic tumour that was studied. The results confirm that ret is frequently expressed in phaeochromocytomas and suggest that it might be an important event in their development and/or progression.

Adrenal Gland Neoplasms↗
PubMed1995

Age-related fluorescence in rat lung collagen.

Mechanical lung properties are impaired with age. In other organs an age-related increase in collagen-linked fluorescence, attributable to advanced glycation endproducts (AGE), or other nonenzymatic reactions such as those related to lipid peroxidation derivatives has been described. Moreover, oxidative processes accelerate some of these reactions. In several tissues, these AGE products have been found to be responsible for protein cross-linking and lack of elasticity. We have evaluated the fluorescence levels of lung collagen in rats aged from 1 to 25 months at two distinct wavelengths: the standard AGE fluorescence (Exc 370 nm/Em 440 nm) and the pentosidine fluorescence (Exc 335 nm/Em 395 nm). In pulmonary tissue fluorescence at both 370/440 nm (p < 0.05) and 335/395 nm (p < 0.001) increases with age. However, a relative stabilization of values is seen in the 25 months group that could be related to the kinetics of fluorescent products in vivo. So, as observed in other tissues, AGE products may increase in pulmonary tissues with time. This may explain the age-associated decline in pulmonary compliance.

Aging↗