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J Prat

Publications and source records attributed to J Prat.

At least 91 records · Page 5Linked to original sources
PubMed1995

Chromatographic evidence for Amadori product formation in rat liver aminophospholipids.

This work presents data which indicates the presence of Amadori product derived from Maillard reaction in aminophospholipids. The presence of 5-HMF, a stable derivative of acid-treated Amadori product, in the phospholipidic fraction from cell membranes was established by HPLC-UV and subsequent GC/MS analysis. The assay for 5-HMF in rat liver phospholipid revealed the presence of this molecule in membrane phospholipids of euglycemic rats, and showed increased glycation levels in membrane phospholipids from streptozotocin-induced diabetic rats (p < 0.001). This gives a new insight to cell membrane physiology and physiopathology.

Animals↗
PubMed1995

[Pleural empyema caused by Corynebacterium sp].

Until recently Corynebacterium sp. had been considered an infrequent cause of infection in humans. In the last few years, however, it has proven its ability to produce severe pulmonary and extrapulmonary infections, generally in immunodeficient hosts. We present a rare case of an immunocompetent man 68 years-old who developed community-acquired pneumonia and left pleural empyema, with Corynebacterium sp. isolated in pleural liquid. Response to thoracic drainage and antibiotic therapy (imipenem and clindamycin) was good.

Aged↗
PubMed1995

Proliferative activity in C-cell hyperplasia and medullary thyroid carcinoma. Evaluation by PCNA immunohistochemistry and AgNORs staining.

C cell hyperplasia (CCH) is a preneoplastic lesion that precedes the development of medullary thyroid carcinoma (MTC) in familial cases. It has been hypothesized that CCH progressively acquires the neoplastic phenotype after presenting some genetic changes that involve oncogenes and tumor suppressor genes. The proliferative activity of nodular C cell hyperplasia (NCCH) and early MTC has been assessed by PCNA (Proliferating Cell Nuclear Antigen) immunohistochemistry and nucleolar organizer regions silver staining (AgNOR) in surgical specimens of seven patients with familial MTC. The ratios of PCNA-positive nuclei in NCCH (mean 1.2, range 0.2-4) were lower than in MTC (mean 2, range 1-7%). The AgNOR scores for NCCH (mean 1.53, range 1.10-1.90) were also lower than for MTC (mean 2.10, range 1.90-2.64). The results suggest that C cells progressively acquire a higher proliferative activity in agreement with the severity of the morphologic changes in the process of hyperplasia-neoplasia that leads to widely invasive MTC.

Adolescent↗
PubMed1995

Mixed strumal and mucinous carcinoid tumor of the ovary.

The first example of mixed strumal and mucinous carcinoid tumor of the ovary is reported. The vast majority of the tumor was composed of carcinoid cells arranged in a trabecular-insular configuration admixed with obvious thyroid follicles. In addition, glands lined by mucin-producing cells were seen in some areas. A transition from the strumal carcinoid component to the mucinous glands was seen. Immunohistochemical studies showed that the strumal and mucinous carcinoid components were positive for chromogranin A, serotonin, and vasoactive intestinal polypeptide, clearly demonstrating that both were neuroendocrine in nature.

Adenocarcinoma, Mucinous↗
PubMed1995

A gonadotrophin dependent stromal luteoma: a rare cause of post-menopausal virilization.

A stromal luteoma is an uncommon ovarian tumour in post-menopausal women, which presents rarely with hyperandrogenism and virilization. We present the case of a 64-year-old woman referred for evaluation of virilization which had developed over 5 years. Testosterone, FSH and LH were markedly inhibited following the administration of a GnRH analogue, suggesting a gonadotrophin dependent, testosterone secreting ovarian tumour, which could not be localized with imaging techniques. Surgery revealed normal sized ovaries with no apparent lesions, but microscopic examination showed a small stromal luteoma in the right ovary and severe stromal hyperthecosis in the adjacent and contralateral ovarian stroma. We conclude that stromal luteoma is an uncommon cause of virilization in post-menopausal women. This case illustrates, to our knowledge for the first time, that a stromal luteoma is not autonomous but is gonadotrophin dependent.

Depression, Chemical↗
PubMed1995

In vitro release of arachidonic acid metabolites, glutathione peroxidase, and oxygen-free radicals from platelets of asthmatic patients with and without aspirin intolerance.

BACKGROUND: An abnormal platelet release of oxygen-free radicals has been described in acetylsalicylic acid (aspirin)-induced asthma, a finding which might suggest the existence of an intrinsic, specific platelet abnormality of arachidonic acid metabolism in these patients. The objective of this study was to evaluate platelet arachidonic acid metabolism in asthmatic patients with or without intolerance to aspirin. METHODS: Thirty subjects distributed into three groups were studied: group 1, 10 healthy subjects; group 2, 10 asthmatic patients with aspirin tolerance; and group 3, 10 aspirin-intolerant asthmatics. Platelets were isolated from blood, preincubated with 3H-arachidonic acid for 30 minutes and then incubated for 10 minutes with platelet activating factor (PAF) and aspirin. Cyclo-oxygenase (thromboxane, PGE2, PGF2 alpha, and HHT) and lipoxygenase (12-HETE) arachidonic acid metabolites were measured by high pressure liquid chromatography. Release of oxygen free radicals after incubation with PAF and aspirin was measured by chemiluminescence. Platelet levels of glutathione peroxidase (GSH-Px) were also measured using spectrophotometry. RESULTS: Platelets from aspirin-intolerant asthmatic patients produced higher quantities of arachidonic acid metabolites than the control group at baseline conditions. This increase was significant only for lipoxygenase products. No differences were found amongst the three groups in the response of arachidonic acid metabolism to PAF and aspirin. Incubation with aspirin but not with PAF caused an increase in oxygen-free radical production in aspirin-intolerant patients whereas in aspirin-tolerant patients PAF, rather than aspirin, was the more potent stimulus for oxygen-free radical production. No differences in GSH-Px levels were found amongst the three groups. CONCLUSIONS: These results suggest that the platelet lipoxygenase pathway is activated in aspirin-intolerant patients and that the production of oxygen-free radicals may differentiate aspirin-tolerant from aspirin-intolerant asthmatic subjects. Our study, however, does not support the hypothesis that an increase in lipoxygenase products may be responsible for oxygen-free radical production. Moreover, a lowered platelet GSH-Px activity does not seem to be involved in this phenomenon.

Adult↗
PubMed1995

Elastofibrolipoma of the mediastinum. A previously undescribed benign tumor containing abnormal elastic fibers.

We report the case of a 57-year-old woman who was found to have a mass in the anterior mediastinum. Surgical excision of the mass revealed a well-delimited lesion 10 cm in largest diameter. Histologically, the mass was composed of mature fat alternating with sclerotic connective tissue, which also contained extensive eosinophilic deposits, similar to the abnormal elastic fibers seen in elastofibroma dorsi. The elastic nature of these deposits was confirmed by elastic staining and electron microscopy. We consider this lesion, which we named elastofibrolipoma, a true benign neoplasm that is characterized by tumoral elastogenesis.

Elastic Tissue↗
PubMed1994

Uterine papillary serous adenocarcinoma. A 10-case study of p53 and c-erbB-2 expression and DNA content.

BACKGROUND: Uterine papillary serous adenocarcinoma (UPSA) is a highly aggressive neoplasm with a great tendency for dissemination. p53 and c-erbB-2 immunoreactivity and DNA ploidy are considered to be indicators of prognosis for endometrial carcinomas. METHODS: Ten cases of patients with UPSA are reported. An attempt to relate pathologic findings with immunohistochemical stains for p53- and c-erbB-2-associated proteins, ploidy, and survival was made. RESULTS: Three patients were classified as having Stage I; three, Stage II; two, Stage III; and two, Stage IV. Myometrial invasion was present with nine tumors and involved over 50% of the myometrial thickness in five. Uterine lymph vessel invasion was detected in seven cases. Peritoneal spread occurred in six patients. Overexpression of p53 was observed in six tumors, immunoreactivity for c-erbB-2 in four, and aneuploidy in seven. However, only peritoneal spread correlated significantly with survival (P < 0.005). CONCLUSIONS: UPSA is a tumor with a high metastatic potential that exhibits immunoreactivity for p53 and c-erbB-2 and aneuploidy more often than that reported for conventional endometrioid adenocarcinomas.

Adult↗
PubMed1994

Human parathyroid hormone-related protein in ovarian small cell carcinoma. An immunohistochemical study.

BACKGROUND: Small cell carcinomas (SCC) are the most common ovarian tumors associated with hypercalcemia. Parathyroid hormone-related protein (PTHrp) is the most frequent cause of hypercalcemia of malignancy. METHODS: The presence of PTHrp in SCC has been studied by immunohistochemistry in formalin fixed, paraffin embedded tissues. A polyclonal antibody against a synthetic peptide corresponding to the first 36-N terminal amino acid residues of PTHrp was used. Normal dog skin, which is rich in PTHrp, was used as a positive control. Absorption tests using the synthetic peptide as antigen were done in all the cases. RESULTS: Immunoreactivity for PTHrp was found in five of seven cases of SCC. The serum calcium levels were elevated in two of these cases, normal in two, and unknown in one. The two negative cases were associated with high serum calcium levels. CONCLUSION: The lack of correlation between immunoreactivity and serum calcium levels can be explained on the basis that immunohistochemistry is dependent on the peptide content of cells rather than on the capability for hormone production and/or release. The results suggest that PTHrp plays a role in the development of hypercalcemia in patients with SCC of the ovary.

Adult↗
PubMed1994

Stromal tumours of the gastrointestinal tract: a clinicopathological and ploidy analysis of 33 cases.

The clinicopathological and DNA flow cytometric data of 33 patients with stromal tumours of the gastrointestinal tract (STGIT) were analysed to select pathological features of prognostic value. Tumours had been previously classified as benign (21 cases) or malignant (12 cases). Data relating to poor prognosis statistically were local invasion, pathological grade, size greater than 10 cm, mitotic index (MI) and necrosis. Pathological grade was related to local invasion. Aneuploidy did not correlate with poor survival although a common trend was detected between both. DNA content may help to predict prognosis of STGIT, but its real value has not yet been clearly established. Currently, stage (invasion), size, MI and pathological grade remain the most useful prognostic factors.

Adolescent↗
PubMed1994

Load transmission through the callus site with external fixation systems: theoretical and experimental analysis.

The fracture callus contribution to the total rigidity of external fixator-fractured bone element was analysed. This study was achieved from both theoretical and experimental perspectives. The theoretical study was done using the finite element method with a three-dimensional model. In this model, both the callus and the development of its elastic characteristics were considered. A series of 38 New Zealand-California white rabbits with tibial fractures treated with some external fixation system was used in this study. Such devices could reproduce either rigid or elastic features. The frame dynamization can be obtained at different fracture healing stages. Animals were classified into four series: (1) rigid fixators, (2) dynamized fixators two weeks after surgery, (3) three weeks after surgery and (4) four weeks after surgery. Tension tests were performed to evaluate callus strength. Theoretical results showed significant levels of callus load transmission (85.5%) when the callus elastic modulus is 1/100 of the elastic modulus of intact bone in an external fixator with rigid features. Experimental analysis of the callus obtained with different external fixator systems did not show differences among them. This fact implies that the immature callus theoretically modelled (E = 100 N mm-2) appears early in the rabbit fracture model (before two weeks, when first dynamization was made), for this reason no differences were found between the two types of treatment (rigid and dynamized systems). This fact questions the reliability of the dynamization process in external fixation of fractures and it implies accurate investigations in the clinical field.

Animals↗
PubMed1994

Stability of carboplatin in 5% glucose solution in glass, polyethylene and polypropylene containers.

The degradation of carboplatin (3.2 mg ml-1) in 5% glucose infusion solution at 25 degrees C and protected from light was investigated. The effects of the material of the container and temperature were also studied. Solutions were prepared in 5% glucose solution and stored in glass bottles, polyethylene (PE) and polypropylene (PP) containers at 40, 50 and 60 degrees C and at 25 degrees C +/- 1 degrees C. Samples were assayed by an HPLC method to determine the residual carboplatin concentration at each time of sampling. Carboplatin degradation followed pseudo-first-order kinetics and no dependence on the nature of the container was found. After 1 month at 25 degrees (+/- 1 degrees)C the change in carboplatin concentration was < 2% of the initial concentration in 5% glucose. These results are in agreement with those predicted by the application of the Arrhenius equation.

Carboplatin↗
PubMed1994

Dietary vitamin C decreases endogenous protein oxidative damage, malondialdehyde, and lipid peroxidation and maintains fatty acid unsaturation in the guinea pig liver.

Guinea pigs were fed during 5 weeks with three different levels of vitamin C in the diet: 33 (marginal deficiency), 660, or 13,200 mg of vitamin C per kg of diet. The group fed 660 mg of vitamin C/kg of diet showed strongly reduced levels of protein carbonyls (46% decrease), malondialdehyde (HPLC; 72% decrease), and in vitro production of TBARS (both stimulated with ascorbate-Fe2+ and with NADPH-ADP-Fe2+; 68% and 71% decrease), increased glutathione reductase activity, and increased vitamin C content (48 times higher) in the liver in relation to the group fed 33 mg/kg. The treatment with 660 mg of vitamin C/kg did not decrease any of the antioxidant defenses studied: superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, GSH, vitamin E, or uric acid. Further supplementation with 13,200 mg vitamin C/kg also reduced protein and lipid peroxidation, but decreased hepatic glutathione reductase and uric acid and resulted in a lower body weight of the animals. Both low (33 mg/kg) and very high (13,200 mg/kg) levels of vitamin C decreased body weight, glutathione reductase, and unsaturation of fatty acids in membrane lipids. The results show that a diet supplying an amount of vitamin C 40 times higher than the minimum daily requirement to avoid scurvy increases the global antioxidant capacity and is of protective value against endogenous lipid and protein oxidation in the liver under normal nonstressful conditions.

Animals↗
PubMed1994

Benign, borderline, and well-differentiated malignant intestinal mucinous tumors of the ovary: a clinicopathologic, histochemical, immunohistochemical, and nuclear quantitative study of 57 cases.

Mucinous ovarian tumors are still a subject of controversy because they can show either intestinal or endocervical differentiation. Morphologic distinction between borderline and malignant tumors is sometimes difficult, and their clinical behavior has not been definitively ascertained. We selected 10 mucinous cystadenomas (MCAs), 32 intestinal mucinous borderline tumors (IMBTs), and 15 well-differentiated mucinous carcinomas (MCCs), all with goblet cells, at least focally. In all cases, we studied the clinicopathologic features, mucin content, intermediate filament expression, and some nuclear quantitative features, namely, the volume-corrected mitotic index (M/Vi), percentage of nucleolated nuclei, mean number of nucleoli per nucleus, percentage of nucleoli touching the nuclear membrane, and mean nuclear area. The quantitative nuclear study included cytometric DNA analysis and the results were expressed as relative mean ploidy value (RMPV) and as diploid-tetraploid or aneuploid histograms. The results of the quantitative study were evaluated statistically. All patients had stage IA tumors, had received surgical therapy only, and were alive and well after a follow-up of more than 5 years. Light microscopic examination revealed that destructive stromal invasion was not present in any MCCs and that IMBTs and MCCs were easily recognizable using the Hart and Norris criteria, later expanded by Hart. Mucin histochemistry and intermediate filament immunohistochemistry failed to detect substantial differences between the diagnostic categories. DNA analysis demonstrated an increase in aneuploid tumors going from IMBTs to MCCs, but these differences were not statistically significant. On the other hand, nuclear quantitative morphology showed significant differences among the three groups of tumors for all features considered. Forward stepwise discriminant analysis highlighted that MCAs, IMBTs, and MCCs were contiguous but different categories. These data support the separation of IMBTs and MCCs into morphologically different categories as underlined by the results of quantitative nuclear morphologic analysis. The favorable outcome of all patients confirms the excellent prognosis of stage I IMBTs and suggests that well-differentiated MCCs without destructive stromal invasion at stage IA could be assimilated, in terms of prognosis and therapy, into stage I IMBTs.

Adenocarcinoma, Mucinous↗
PubMed1994

Aggressive natural killer cell leukaemia/lymphoma in two patients with lethal midline granuloma.

We report two patients with leukaemic proliferations of large granular lymphocytes. The immunophenotype study showed that the leukaemic cells were positive for CD2, CD38, CD56 and anti-HLA-DR monoclonal antibodies and negative for other T-cell (CD3, CD4, CD8) and B-cell markers (CD19, CD20 and surface immunoglobulins). The clinical course was acute and a diagnosis of aggressive natural killer cell leukaemia/lymphoma was made. No clonal rearrangements of either C beta T-cell receptor or JH immunoglobulin genes were found. Functional studies done in one patient demonstrated non-restricted cytotoxic activity after activation with IL-2. Lethal midline granuloma had been previously diagnosed in both patients. A possible relationship between this entity and the natural killer cell leukaemia is discussed.

Antigens, CD↗