Search PubMed⌕ Search

Biomedical subjects

B Piura

Publications and source records attributed to B Piura.

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

Myasthenia gravis associated with malignant mixed Mullerian tumor of the uterus.

Myasthenia gravis is a neurologic disorder characterized by intermittent muscle weakness which improves after anticholinesterase medication. The pathogenesis of myasthenia gravis is associated with production of autoantibodies to nicotinic acetylcholine receptor in the motor end plate. Most patients do not have an underlying neoplasm, but in 10-15% of the cases, a thymoma may be detected. Apart from thymoma, no other tumor type or organ has consistently been associated with myasthenia gravis. We describe an unusual case of myasthenia gravis in a patient with malignant mixed Mullerian tumor of the uterine corpus. Initial histology revealed malignant mixed Mullerian tumor of a predominant carcinomatous element. At that time, there were no symptoms of muscle weakness. Intraabdominal metastases were detected later, concommitantly with symptoms of muscle weakness and the diagnosis of myasthenia gravis. Histology of the metastases disclosed an exclusive mesenchymal element with striated muscle differentiation. To the best of our knowledge this case is the first report of myasthenia gravis in a patient with malignant mixed Mullerian tumor of the uterine corpus. We propose that the mechanism contributing to myasthenia gravis in this patient was closely associated with the evolving histology and with the nature of the tumor, so that antibodies produced to muscle-like epitopes exposed by malignant cells could have cross-reacted with acetylcholine nicotinic receptors and caused myasthenia gravis.

Female↗
PubMed1997

Distinct patterns of expression of interleukin-1 alpha and beta by normal and cancerous human ovarian tissues.

Immunohistochemical staining of normal and cancerous ovarian tissues has demonstrated that both IL-1 alpha and IL-1 beta are more strongly expressed in cancerous than in normal tissues and are secreted mainly by epithelial cells. We have shown by bioassay and immunoassay that cancerous, but not normal ovarian tissues constitutively secrete IL-1 in vitro. Activation of cancerous ovarian tissues by lipopolysaccharide (LPS) increased its capacity to secrete IL-1. Normal ovarian tissues secreted low amounts of IL-1 only after prolonged stimulation (72-96 h) by high doses of LPS (10-100 micrograms/ml). On the other hand, constitutive IL-1 was detected in homogenates of normal ovarian tissues and stimulation by LPS increased its capacity to produce IL-1. IL-1 beta was the main type of IL-1 secreted by cancerous ovarian tissues. IL-1 alpha was detected at lower levels. In contrast, in normal tissues similar amounts of both IL-1 alpha and IL-1 beta were detected in the supernatants. The levels of both types of IL-1, and also the bioactivity of IL-1 were significantly higher in cancerous than in normal ovarian tissues. Established primary cell lines from normal ovarian tissues did not secrete IL-1 into supernatants but did express it at very low levels. Stimulation with LPS did not affect the capacity of these cell lines to secrete IL-1 but it increased their capacity to express it. In contrast, primary established epithelial cell lines from cancerous ovarian tissues did secrete and express high levels of IL-1 and these levels were increased under stimulation with LPS. Cancerous ovarian tissues did not only secrete higher levels of both IL-1 alpha and beta than normal ovarian tissues, but also the mechanism controlling the secretion of these factors in cancerous ovarian tissues seemed to be different from that found in normal ovarian tissues. Our results suggest that paracrine/autocrine factors may be involved in the regulation of both types of IL-1 secreted by ovarian tissues. These cytokines may play a role in regulating the physiological, pathophysiological and oncogenic processes of the ovary.

Cell Line↗
PubMed1996

Adenocarcinoma of the uterine cervix: a study of 37 cases.

In a study of 37 patients diagnosed with cervical adenocarcinoma between 1961 and 1994, clinical and pathologic findings were evaluated. Of the 37 patients, 27 (73%) had a pure adenocarcinoma, five (13.5%) had a collision tumor and five (13.5%) had an adenosquamous carcinoma. Twenty-six patients (70.3%) were diagnosed in Stage I, and 11 (29.7%) patients in Stage II, III, and IV. Two patients (5.4%) were treated with simple hysterectomy alone, nine (24.3%) with simple hysterectomy followed by radiotherapy, eight (21.6%) with radical hysterectomy alone, five (13.5%) with radical hysterectomy followed by radiotherapy, nine (24.3%) with radiotherapy alone, one (2.7%) with radiotherapy followed by simple hysterectomy, and three (8.1%) received no treatment. The actuarial 5-year survival rate was 69%. It is suggested that for patients with small early-stage disease, radical hysterectomy should be primary treatment and postoperative adjuvant radiotherapy would be advocated if high-risk features are histologically demonstrated. For all other patients, radiotherapy should be primary treatment.

Adenocarcinoma↗
PubMed1996

Diagnosis and management of malignant germ cell ovarian tumors in young females.

Germ cell tumors (GCT) compose most of the preadolescent malignant ovarian tumors; dysgerminoma being the most common (48%), followed by endodermal sinus tumor, immature teratoma, mixed GCT and embryonal carcinoma. The percentage of malignant epithelial ovarian tumors rises with increasing age, while that of the GCT tumors declines. Of all tumor markers discussed, only AFP and hCG are being routinely monitored. Their most effective use is in monitoring response to therapy and detecting recurrences early. The current therapeutic regimens are presented, among them bleomycin, etoposide and platinol (BEP) and other new regimens; their influence on the patients' fertility is discussed. Further improvement in the prognosis of these young patients will hopefully follow development of new surgical and chemotherapeutic approaches.

Adolescent↗
PubMed1995

Malignant germ cell tumors of the ovary: a study of 20 cases.

In a study of 20 patients diagnosed with malignant ovarian germ cell tumors between 1961 and 1993, clinical and pathologic findings were evaluated. Of the 20 patients, seven (35%) had dysgerminoma, two (10%) endodermal sinus tumor, three (15%) malignant teratoma, one (5%) malignant struma ovarii, one (5%) primary ovarian carcinoid, two (10%) benign teratoma with malignant transformation, and four (20%) combination germ cell tumor. Twelve patients (60%) had stage IA, five (25%) stage IC, and three (15%) stage IIIC. Twelve patients (60%) underwent conservative surgery and eight (40%) had at least bilateral salpingo-oophorectomy. At follow-up, 18 patients (90%) were alive free of disease, one (5%) had died of disease, and one (5%) had died of intercurrent disease. The actuarial 5-year survival rate was 93.3%. It is concluded that for young women who wish to preserve child-bearing capacity, regardless of the stage of the tumor, fertility-preserving surgery with complete surgical staging followed, if necessary by cisplatin-based combination chemotherapy is an appropriate and definitive treatment in the absence of involvement of the contralateral ovary and uterus. For patients in whom child-bearing capacity is not an issue, surgery should include total abdominal hysterectomy and bilateral salpingo-oophorectomy with complete staging, followed if necessary by chemotherapy.

Adolescent↗
PubMed1995

Current concepts in management of epithelial ovarian tumors of low malignant potential.

Approximately 15 percent of epithelial ovarian tumors are tumors of LMP. Epithelial stratification, cellular atypia, mitotic activity, and abscence of ovarian stromal invasion set the histopathological criteria for diagnosis. Serous and mucinous tumors of LMP represent 80 to 95% of all cases. These tumors occur in patients at a younger age than those with invasive cancer and many times in fertile women who have not accomplished their family planning yet. Ovarian tumors of low malignant potential carry a favorable prognosis in comparison to invasive epithelial ovarian cancer. The recurrence rate after surgery for these tumors ranges from 10 percent to 30 percent, occurring as late as 10 or more years after presentation. The majority of patients (80-92 percent) with ovarian tumors of LMP present with stage I disease. Peritoneal implants display a range of histologic appearances, ranging from benign glands to those with features of invasive disease. Tumor markers such as CA-125 are not as useful in tumors of LMP as in invasive ovarian carcinoma. Elevated CA-125 are found only in patients with advanced serous tumors of LMP; thus, other markers such as transvaginal Doppler measurements of vascular resistant index has been suggested for possible differentiation between a benign and LMP ovarian tumors before surgery. Primary conservative surgery consisting of unilateral salpingo-oophorectomy is considered to be an appropriate treatment for young women with stage Ia ovarian tumors of LMP who wish to retain their fertility potential. Up to 70 percent of women who underwent conservative surgery subsequently conceive.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomarkers, Tumor↗
PubMed1995

Dose intensity of cisplatin-based chemotherapy in epithelial ovarian carcinoma. An important factor affecting survival.

Forty-three patients with epithelial ovarian carcinoma, were treated by cyclophosphamide and cisplatin (CP) following initial laparotomy. The mean dose intensity (DI) and mean relative dose intensity (RDI) respectively were for cyclophosphamide: 166.69 mg/sqm/week and 0.67, and for cisplatin: 16.29 mg/sqm/week and 0.65. The mean average relative dose intensity (ARDI) was 0.66. The three-year survival for all patients was 44.3%. The three-year survival for patients receiving cyclophosphamide with a RDI of more than median value was 63.82%, while for patients receiving cyclophosphamide with a RDI of less than median value three-year survival was 26.3% (p < 0.02). The three-year survival for patients receiving cisplatin with an RDI of more than median value was 62.01%, as compared to 24.17% for patients receiving cisplatin with a RDI of less than median value (p < 0.02). The three-year survival for patients receiving the CP regimen with an ARDI of more than median value was significantly higher than that for patients receiving the CP regimen with an ARDI of less than median value (63.82% versus 26.03%, p < 0.02). Dose intensity of cisplatin-based chemotherapy in epithelial ovarian carcinoma is an important factor affecting survival.

Adult↗
PubMed1994

[CA 125 in diagnosis and prognosis of epithelial ovarian cancer].

In 59 women with epithelial ovarian cancer serum CA 125 was determined and they were then followed for 3 years. In those with active disease, mean serum CA 125 (289 units/ml) and positivity rate (85%) were significantly higher than in those without evidence of disease (44 units/ml and 17%, p = 0.001 and p < 0.001, respectively). Actuarial 3-year survival curves were calculated according to CA 125 serum level. 91% of those with CA 125 lower than 35 units/ml survived 3 years, as compared to 40% of those with CA 125 levels higher than 35 units/ml (p < 0.01). In ovarian cancer CA 125 serum level correlates with the state of the disease and can be used in the prediction of 3-year survival.

Actuarial Analysis↗
PubMed1994

Granulosa cell tumor of the ovary: a study of 18 cases.

In a study of 18 patients diagnosed with ovarian granulosa cell tumor between 1961 and 1992, clinical and pathologic findings were evaluated. Of the 18 patients, 15 (83.3%) were diagnosed in Stage I and three (16.7%) in Stage III or IV. Six patients (33.3%) underwent conservative surgery and in 12 (66.7%) total abdominal hysterectomy and bilateral salpingo-oophorectomy was performed. At follow-up three patients (16.6%) had died of disease, three, 16 and 288 months, respectively, after initial surgery. The actuarial 5-year survival rate for Stage I was 100%, while that for Stages III and IV combined was 33.3% (P < 0.05). It is concluded that for patients with Stage IA, unilateral oophorectomy seems to be adequate treatment and for those with more than Stage IA, surgery should include total abdominal hysterectomy and bilateral salpingo-oophorectomy. Postoperative adjuvant chemotherapy is advocated for patients in whom spread of tumor beyond the ovaries has occurred.

Adolescent↗
PubMed1994

Metastasis-associated mts1 gene expression correlates with increased p53 detection in the B16 murine melanoma.

MTS1 is a metastasis-associated gene highly expressed in high-metastasis tumors. Here we show that the expression of the suppressor gene p53 protein correlates with mts1 expression. In murine melanoma B16-F1 cells, alpha-melanocyte-stimulating hormone up-regulated mts1 and increased p53 positivity in immunohistochemical tests. In B16-ML8 cells, retinoic acid reduced mts1 expression together with a reduction of p53 positivity. The variation of p53 in association with mts1 gene expression suggests that the mts1 product might interact with and stabilize p53. Taxol-induced aneuploidy increased the proportion of G0G1 phase cells, increased p53 positivity, and down-regulated mts1. This suggests that mts1 transcription may have been negatively regulated, possibly on account of the stabilization of microtubules by taxol. We postulate that the control of G1-S transition by p53 could be due to p53 sequestration by mts1, leading to microtubule depolymerization and signaling entry, into the S phase. Thus, a coordinated function of mts1 and p53 may be involved not only in uncontrolled growth but also in cytoskeletal depolymerization that could lead to cancer invasion.

Calcium-Binding Proteins↗