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Biomedical subjects

J Prat

Publications and source records attributed to J Prat.

At least 127 records · Page 7Linked to original sources
PubMed1992

Rhabdomyosarcomas developing in association with mediastinal germ cell tumours.

Two mediastinal rhabdomyosarcomas that arose in association with germ cell tumours are reported. One presented as a small component of a mixed germ cell tumour with yolk sac and immature teratomatous elements. The other appeared as a large mass 4 months after diagnosis of a yolk sac carcinoma that had been treated with chemotherapy. The first patient was alive and free of disease 7 years later, whereas the second died of tumour 3 months post-operatively. The proportion of rhabdomyosarcoma within the germ cell tumours appears to have influenced the prognosis of these patients. This observation emphasizes the necessity of performing a thorough search for sarcomatous elements and quantifying their relative proportion in germ cell tumours of the mediastinum.

Adult↗
PubMed1992

Biomechanical consequences of callus development in Hoffmann, Wagner, Orthofix and Ilizarov external fixators.

A theoretical analysis by a finite elements model (FEM) of some external fixators (Hoffmann, Wagner, Orthofix and Ilizarov) was carried out. This study considered a logarithmic progress of callus elastic characteristics. A standard configuration of each fixator was defined where design and application characteristics were modified. A comparison among standard configurations and influence of every variation was made with regard to displacement and load transmission at the fracture site. An experimental evaluation of standard configurations was performed with a testing machine. After experimental validation of the theoretical model was achieved, an application of physiological loads which act on a fractured limb during normal gait was analysed. A minimal contribution from an external fixator to the total rigidity of the bone-callus-fixator system was assessed when a callus showing minimum elastic characteristics had just been established. Insufficient rigidity from the fixation devices to assure an adequate immobilization during the early stages of fracture healing was verified. However, regardless of the external fixator, callus development was the overriding element for the rigidity of the fixator-bone system.

Biomechanical Phenomena↗
PubMed1992

Endometrial stromal nodule with smooth and skeletal muscle components simulating stromal sarcoma.

A stromal nodule was found in a hysterectomy specimen from a 29-year-old woman with a history of menometrorrhagia. Endometrial curettings had revealed stromal cells admixed with well-defined bundles of smooth muscle cells, a finding that had led to the erroneous diagnosis of stromal sarcoma invading the myometrium. Ultrastructural and immunohistochemical studies demonstrated several components: stromal cells, smooth muscle cells, sex-cord-like structures, and a hitherto undescribed component of skeletal muscle cells.

Adult↗
PubMed1992

Release of peptide leukotriene into nasal secretions after local instillation of aspirin in aspirin-sensitive asthmatic patients.

Although the mechanism of aspirin-induced asthma and rhinitis is unknown, it has been suggested that adverse nasal and bronchial reactions are caused by an increased production of lipoxygenase products. In examining this hypothesis we have measured the release of peptide leukotrienes (PeptLTs), 15-HETE, and prostaglandins in nasal fluids obtained by nasal lavages after instillation of acetylsalycilic acid (ASA) and placebo (saline). Ten ASA-sensitive asthmatics, 10 ASA-insensitive asthmatics, and seven healthy subjects were challenged in a double-blind study with normal saline and 12 mg of ASA. Twelve mg were administered based on the results of a previous study that showed that this dose caused minor to moderate symptoms in ASA-sensitive patients. PeptLTs, LTB4, 15-HETE, PGE2, PGF2 alpha, and PGD2 were measured by radioimmunoassay methods. Significant levels of PeptLTs were detected in sensitive asthmatic patients 60 min after nasal challenge. This change was associated with a significant increase in symptoms. No increase in PeptLTs levels were found, however, in either insensitive patients or healthy subjects. Inhibition of PGE2 and PGF2 alpha release was detected in the three groups after ASA administration. ASA also inhibited PGD2 release in insensitive asthmatic patients but not in both sensitive patients and healthy subjects. These results suggest that an abnormal release of PeptLTs in ASA-sensitive asthmatic patients contributes to nasal and bronchial adverse reactions. The lack of effects on PGD2 release suggests that mast cells from ASA-insensitive patients are more sensitive to ASA than those from sensitive asthmatic patients and healthy subjects.

Administration, Intranasal↗
PubMed1991

Simultaneous carcinoma involving the endometrium and the ovary. A clinicopathologic, immunohistochemical, and DNA flow cytometric study of 18 cases.

Eighteen carcinomas involving both the endometrium and the ovary were studied. Stage, size, bilaterality and pattern of ovarian involvement, histologic types and grades, presence of endometrial hyperplasia or ovarian endometriosis, myometrial, tubal, lymphatic and blood vessel invasion, and follow-up of the patients were all evaluated. Accordingly, the cases were classified as follows: Group A (nine cases), two separate primary tumors; and Group B (nine cases), uterine primaries with ovarian metastasis or ovarian primaries with uterine metastasis. Immunohistochemical stains (CAM 5.2, wide-spectrum keratin, vimentin, carcinoembryonic antigen (CEA), CA 12.5, CA 19.9) were performed in all cases. Flow cytometric determination of nuclear DNA was done in 13 (seven Group A and six Group B tumors). Of the nine cases with independent primary tumors, seven showed different immunohistochemical profiles in the ovarian and uterine tumors, whereas only four of the nine metastatic ones had similar staining characteristics. Five cases with independent primary tumors, but only one of the metastatic group, exhibited different aneuploid stemlines in the endometrial and ovarian tumors. The other seven (two independent and five metastatic) cases had similar DNA indexes in both tumors. Immunohistochemical and DNA flow cytometric study may be of some value for the distinction between metastatic and independent tumors, but differential diagnosis must presently rely largely upon conventional clinicopathologic criteria.

Adenocarcinoma↗
PubMed1991

Immunohistochemical study of sarcoma-like mural nodules in a mucinous cystadenocarcinoma of the ovary.

We describe an ovarian mucinous cystadenocarcinoma with several sarcoma-like mural nodules (SLMN). The distinction between these lesions and foci of anaplastic carcinoma is important because of the poor prognosis of the latter. We have studied the potential value of immunohistochemistry in the differential diagnosis of these two lesions. In contrast to an anaplastic carcinoma, which was largely composed of keratin-positive cells, SLMN were negative or only focally positive. Therefore, in distinguishing SLMN from foci of anaplastic carcinoma, keratin strains may be added to other gross and microscopical differential features, such as size, demarcation, and presence or lack of obvious carcinomatous elements.

Adult↗
PubMed1991

Keratin expression in normal vulva, non-neoplastic epithelial disorders, vulvar intraepithelial neoplasia, and invasive squamous cell carcinoma.

The expression of AE1, AE2, AE3, and CAM 5.2 antikeratin monoclonal antibodies was investigated in 68 vulvar specimens by an avidin-biotin complex (ABC) method. They included normal vulva (NV, 10), non-neoplastic epithelial disorders (NNED, 31), vulvar intraepithelial neoplasia (VIN, 17), and squamous cell carcinoma (SCC, 10). AE1 weakly stained the basal cell layer in NV, exhibited a uniform suprabasal stain in hyperplasia, failed to stain dysplastic areas in VIN I-II, and was patchy and disorganized in VIN III and SCC. AE2 stained the upper third of the epithelium in NV, NNED, and VIN I-II, but it failed to stain VIN III basaloid and SCC; VIN III bowenoid was focally positive. AE3 offered little information, because it stained all lesions; VIN III and SCC, however, exhibited a patchy and disorganized stain. CAM 5.2 was expressed in only half of the cases of VIN III basaloid and in one case each of VIN I-II and SCC. We conclude that keratin expression varies according to the degree of dysplasia; AE1 may serve to separate certain cases of NNED from VIN I-II; AE2 and CAM 5.2 are useful to differentiate both histologic types of VIN III.

Antibodies, Monoclonal↗
PubMed1991

Blood lymphocytes are sensitized to branchial plexus nerves in patients with neuralgic amyotrophy.

The percentage of lymphocytic subsets in the blood of cases with neuralgic amyotrophy (NA), and the proliferative response of blood lymphocytes cultured with different nerve extracts, obtained from normal subjects at postmortem, were examined in 6 patients with NA and in 18 age-matched controls with shoulder pain not related to NA. Most (5/6) NA patients had decreased CD3 values and increased CD4/CD8 ratios due to a decreased of the CD8 subset. Lymphocytes of NA patients increased their blastogenic activity in cultures with nerve extracts from different brachial plexus nerves and its branches, but not in cultures with extracts of sacral plexus nerves. Cultures did not respond to nerve extracts in any of the control cases, although mitogenic activity was similarly elicited in cultured lymphocytes stimulated with phytohemagglutinin in both control cases and NA patients. These results suggest that NA is probably an immune mediated disease.

Adolescent↗
PubMed1991

[Multilocular peritoneal inclusion cysts in puerperium].

We report the case of a 26 year old female with low abdominal pain occurring post-partum. Ultrasonography revealed the existence of pelvic cysts. Laparotomy allowed the resection of the cysts interpreted at that time as hydatic cysts. Four months later the patient was readmitted because of a recurrence of the cysts. Pathological examination made the final diagnosis of multilocular peritoneal inclusion cysts. The literature on this rare condition, previously denominated cystic benign mesothelioma, is reviewed. Recurrence may be prevented by the use of sclerosing agents during the surgical intervention.

Adult↗
PubMed1990

[Peripheral T-cell lymphoma. Morphologic, immunophenotypic and immunogenotypic studies of 10 cases].

We describe the histopathology, immunophenotype and immunogenotype of 10 cases of peripheral T-cell lymphoma. The majority of patients showed disseminated disease at the time of diagnosis. From a histopathological view point the cases were classified into 5 types: T zone lymphoma (4 cases); Lennert lymphoma (2 cases); pleomorphic lymphoma, small all type (2 cases); pleomorphic lymphoma of medium-sized cell type (1 case); pleomorphic lymphoma of large cell type (1 case). In most of them the neoplastic cells demonstrated a mature T-cell phenotype: CD3+, CD4+, CD8-, CD43+, CD45RO+, CD45RA-, CD20- and surface immunoglobulins. All cases studied displayed gene rearrangements for the T-cell receptor beta chain while the immunoglobulins genes remained in germinal configuration. Antibodies against the human T-cell lymphotropic virus type I were not found in the 9 samples studied.

Adult↗
PubMed1990

Ovarian tumors with functioning stroma. An immunohistochemical study of 100 cases with human chorionic gonadotropin monoclonal and polyclonal antibodies.

The frequency of stromal activation and its possible relation to human chorionic gonadotropin (HCG) or HCG-like secretion by tumor cells has been studied in 100 nonselected, consecutive, primary and secondary ovarian neoplasms. Stromal luteinization was present in 13 cases and stromal condensation in 16. The types of tumors most commonly associated with activation of the ovarian stroma were as follows: mucinous tumors (11 cases), endometrioid and clear cell tumors (six cases), and metastasis of gastrointestinal adenocarcinomas (six cases). We used to commercial polyclonal antibodies as well as four more specific monoclonal antibodies (FBT-10, FBT-11, FB-12, and FB-13). Immunohistochemical studies (peroxidase-antiperoxidase [PAP]) yielded the following staining results: polyclonal HCG and/or polyclonal beta-HCG positivity was present in 22 tumors (12 had an activated stroma and ten an inactive one). In addition, 44 tumors were positive for FBT-10, FBT-11, FB-12, and FB-13 monoclonal antibodies (18 showed activation of the stroma, which was inactive in 26). Only 11 of the 56 HCG-negative tumors exhibited activation of the stroma. Thus, positivity for HCG was more frequently found in tumors with morphologically active stroma than in those with an inactive one. However, five HCG polyclonal positive tumors--three of them exhibiting activation of the stroma--were negative for the monoclonal antibodies. It appears that HCG plays a role in the activation of the stroma of some ovarian tumors, yet, HCG-like substances as well as other factors may also be involved.

Adenocarcinoma↗
PubMed1990

[Ocular toxoplasmosis in patients with acquired immunodeficiency syndrome].

Ocular toxoplasmosis is an uncommonly reported complication in patients with acquired immunodeficiency syndrome. Three patients with human immunodeficiency virus (HIV) infection and ocular toxoplasmosis are reported. In two of them, cerebral toxoplasmosis was associated. Ocular involvement presented as exudative chorioretinitis, bilateral in 2 cases and unilateral in 1. The diagnosis was made on the basis of ocular disease associated with lesions consistent with toxoplasmosis of central nervous system (CNS) and response to antitoxoplasma treatment in one case, and ocular disease with rising antitoxoplasma serologic titers in the remaining two. Initial therapy included pyrimethamine plus sulfadiazine in 2 cases and pyrimethamine plus clindamycin in 1. The 2 patients treated with sulfadiazine showed hypersensitivity features, and clindamycin had to be substituted. The response to therapy was favorable, although one patient died few days after the development of CNS lesions. When chorioretinitis develops in a patient with HIV infection, ocular toxoplasmosis should be considered. As CNS involvement is commonly associated and relapse after the withdrawal of therapy is likely, these patients should be treated as those with isolated toxoplasma encephalitis.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Postmenopausal androgen secreting ovarian tumour: pathophysiological implications; a case report.

Hyperandrogenism in women is usually accompanied by a disruption of the hypothalamic-pituitary-ovarian axis; however, the precise effect of chronically elevated androgens on this axis is poorly understood. We report a postmenopausal woman with a virilizing ovarian tumour in whom the effects of chronic testosterone secretion on the hypothalamic-pituitary axis was investigated. A 56-year-old woman was evaluated for hirsutism and hyperandrogenism of recent onset. Peripheral serum testosterone was high (19.4 nmol/l), while gonadotropins were below normal for a postmenopausal woman, FSH (19.7 IU/l) being higher than LH (10.3 IU/l). Four LH and 1 FSH pulse were detected over 4 h. A left intraovarian testosterone secreting tumour, shown by catheterization of the ovarian veins and containing imperfect crystalloids of Reinke, was excised. Postoperatively, peripheral testosterone became undetectable, while gonadotropins rose to normal postmenopausal values. This patient's LH/FSH ratio was less than 1, in contrast with other situations of chronic hyperandrogenism. This could be explained by the concomitant hypoestrogenic state, and/or the theoretical absence of inhibin. The interest of this case resides in that it constitutes an appropriate model for studying the effects of testosterone on LH and FSH secretion in the absence of the other two classically involved modulators, namely oestrogens and inhibin.

Androgens↗