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Biomedical subjects

B Petit

Publications and source records attributed to B Petit.

At least 19 recordsLinked to original sources

Bone formation in hydroxyapatite tricalcium phosphate ceramic implants used in the treatment of the postenucleation socket syndrome.

PURPOSE: To determine the histopathologic changes in coralline hydroxyapatite tricalcium phosphate (HA-TCP) blocks used in the treatment of the postenucleation socket syndrome (PESS). METHODS: Twenty-four patients were treated with HA-TCP blocks placed directly into the orbital fat to correct the PESS. Eight of these patients required partial removal of the material for various reasons between 32 and 371 days after the initial operation. The orbital implants were decalcified and processed for light and electron microscopic examination. RESULTS: Light microscopy demonstrated fibrovascular ingrowth into the pores of the implant in all cases. Osteogenesis was observed in three cases in the periphery of the implant. Ossification occurred in the implants after a mean implantation duration of 276 days versus 67 days in cases without ossification. CONCLUSION: Implants of HA-TCP, a new material used in ophthalmology, demonstrate the presence of fibrovascular ingrowth, reflecting the excellent biointegration of this material.

Adolescent↗

Differential responses of olfactory neurons to axotomy at embryonic and postnatal stages.

In the nervous system, apoptosis is a major process during embryonic and postnatal stages. In chick, experimental cell death can be obtained by axotomy. We have compared the responses of olfactory neurons to axotomy at embryonic stage E17 and postnatal stages.Forty-three chicken embryos and 32 young chickens less than 3 weeks old were used. We combined optic microscopy, electronic microscopy, terminal (TdT)-mediated dUTP-nick end labeling (TUNEL) method and gel electrophoresis of genomic DNA to analyze cell death. Cells in synthetic phase were labeled by bromodeoxyuridine injected i.p. and detected by immunohistochemistry. Apoptotic index and 5-bromo-2'-deoxyuridine (BrdU) labeling index were calculated for each stage. The Wilcoxon test was used for statistical analysis. A P value <0.05 was considered significant. Within 3 days following axotomy in E17 chicken embryos, there was no significant increase of apoptosis on the lesion side analyzed 3, 6, 12, 18, 24, 48 or 56 h later. A slight increase of bromodeoxyuridine incorporation appeared at 3 h, was weakly significant at 24 h (P=0.045) and the return to basal rate took place at 48 h. In postnatal stages, an apoptotic wave appeared 12 h after axotomy, reached a maximum at 24 h, and then decreased between 48 h and 72 h. A significant elevation of bromodeoxyuridine incorporation occurred on 48 h with a 24 h delay after the peak of apoptotic death. This differential response to axotomy in embryos and postnatal chickens might be due to a less complete maturation and higher plasticity of embryonic olfactory neurons corresponding to different requirement for survival and differentiation factors. Thus the embryonic or immature neurons would depend more on local epithelial environment and mature or postnatal neurons would require target-derived survival factors and die from apoptosis after their shortage resulting from axotomy.

Aging↗

Characteristics of secondary acute lymphoblastic leukemia with L3 morphology in adult patients.

Secondary acute lymphoblastic leukemia (sALL) is an uncommon condition and sALL with L3 morphology is still less frequent. Here, we compare the characteristics of available cases of L3 sALL (16 patients, including 12 previously published cases and 4 personal cases) to those of de novo L3 ALL and of non L3 sALL. Two patients with L3 sALL obtained a CR after aggressive treatment of their leukemia. Compared with 24 patients from the literature with de novo L3 ALL, L3 sALL patients were characterized by an older age (median 46 vs. 29.5 years, p = 0.0003) and by a poor prognosis (complete responses: 2/16 vs. 19/24, p = 0.0001, median survival: 0.46 month vs. undetermined, p < 0.0001). In comparison with 19 patients from the literature with non L3 sALL, L3 sALL patients were characterized by a high Male/Female ratio (14/2 vs. 8/11, p = 0.01), a frequent history of Hodgkin's disease (12/16 vs. 7/19, p = 0.04) and, again, by a poor prognosis (complete responses: 2/16 vs. 13/18, p = 0.0001, median survival 0.46 vs. 13 months, p = 0.001). In conclusion, though based on a small group of heterogeneously treated patients, some characteristics of L3 sALL, seem to emerge, compared both with de novo L3 ALL and with non L3 sALL, the most prominent being its extremely poor prognosis.

Adult↗

p53 gene mutations are associated with poor survival in low and low-intermediate risk diffuse large B-cell lymphomas.

BACKGROUND: p53 alterations have been associated with a poor prognosis in aggressive B-cell lymphoma. We investigated the clinical relevance of p53 status in diffuse large B-cell lymphoma (DLBCL), focusing on patients who belong to lower risk groups of the international prognostic index and were uniformly treated. We aimed to determine whether this biological marker could identify among such patients those with a pejorative outcome who could benefit from a distinct therapeutic approach. PATIENTS AND METHODS: We studied 69 patients presenting with no, one (low-risk, n = 40) or two (low-intermediate risk, n = 29) risk factors treated with an anthracyclin-containing induction regimen. p53 exons 5-8 mutations were screened for using denaturing gradient gel electrophoresis and confirmed by direct sequencing. Immunohistochemical detection of p53 protein and of its downstream target p21 were also evaluated in 60 of 69 cases. RESULTS: p53 mutations were detected in 16 of 69 (23%) lymphoma samples. The presence of a p53 gene mutation affected survival (P = 0.01), with a 6-year survival rate estimated to be 44% in mutated patients, compared with 79% in non-mutated ones. Using a stepwise Cox model, p53 mutation constituted the only parameter affecting survival (relative risk = 2.7, P = 0.03). A p53+/p21- immunohistochemical pattern (n = 15), suggestive of a disrupted p53 function, strongly correlated with p53 gene status and was associated with a lower 6-year survival rate when compared with a p53(-) or p53+/p21+ phenotype (47% versus 74%, P = 0.05). CONCLUSIONS: p53 alterations constitute a pejorative biological indicator able to discriminate among clinically defined lower risk patients with DLBCL.

Adult↗

Real-time PCR for quantification of human herpesvirus 6 DNA from lymph nodes and saliva.

A real-time quantitative PCR assay has been developed to measure human herpesvirus 6 (HHV-6) DNA in biological specimens. The assay sensitivity was 10 copies of DNA per well, with a linear dynamic range of 10 to 10(7) copies of HHV-6 DNA. Intra- and interassay variations were, respectively, 0.88 and 0.8% for samples containing 10(2) DNA copies, 0.99 and 0.96% for samples containing 10(4) copies, and 0.76 and 0.9% for samples containing 10(6) copies. Among 34 saliva samples from healthy subjects, 26 were found to contain HHV-6 DNA (76.5%; median, 23,870 copies/ml), and following a single freeze-thaw cycle, 25 of the same samples were found to be positive for HHV-6 DNA, although at a statistically significantly lower concentration (median, 3,497 copies/ml). The assay enabled detection of HHV-6 DNA in lymph node biopsies from patients with Hodgkin's disease (HD) (13 of 37 patients [35.1%]), B-cell neoplasms (8 of 36 patients [22.2%]), and T- or NK-cell neoplasms (3 of 13 patients [23.1%]), with concentrations ranging from 100 to 864,640 HHV-6 copies per microg of DNA (HHV-6B being found in every case except two). All HD patients infected with HHV-6 presented clinically with the nodular sclerosis subtype of HD. The real-time quantitative PCR assay developed here was simple to perform and was sensitive over a wide range of HHV-6 concentrations. It therefore appears to be of potential value in clinical investigation or diagnosis of HHV-6 infection.

Adult↗

[Kikuchi-Fujimato disease].

UNLABELLED: Chronic adenopathies usually reveal lymphoma or infectious disease, particularly tuberculosis. CASE REPORT: We report a case of Kikuchi-Fujimato's disease revealed by cervical adenopathies, associated with fever and inflammatory syndrome. CONCLUSION: The diagnosis of Kikuchi-Fujimato's disease lies on histological examination. Resolution is faster with steroids.

Biopsy↗

[Hodgkin's disease limited to intrathoracic sites. Case report].

UNLABELLED: Hodgkin's disease without peripheral lymphadenopathy or hepatosplenomegaly is exceptional. CASE REPORT: Hodgkin's disease was revealed by lung nodules, one of them cavitating, with mediastinal enlargement. Diagnosis was confirmed on a video-assisted pleuroscopic biopsy. CONCLUSION: Hodgkin's disease should be considered in case of mediastinal enlargement with lung nodules.

Adolescent↗

MLH1 and MSH2 protein immunohistochemistry is useful for detection of hereditary non-polyposis colorectal cancer in young patients.

AIMS: Hereditary non-polyposis colorectal cancer is related to germline mutations of DNA mismatch repair genes MLH1 and MSH2, which result in microsatellite instability and loss of protein expression of the corresponding mutated gene in the tumour tissue. METHODS AND RESULTS: MLH1 and MSH2 protein expression was studied by immunohistochemistry in paraffin-embedded surgical samples of 100 colorectal adenocarcinomas occurring before 50 years of age. Absence of tumour cell nuclear staining with positive internal control (normal mucosa, lymphoid follicles) was considered negative. Loss of MLH1 or MSH2 expression was found in 20 cases with microsatellite instability in 15 cases. Twelve of these patients had a family history of colorectal cancer. Compared with MLH1- and MSH2-positive cases, MLH1- or MSH2-deficient colorectal adenocarcinomas were significantly associated on multivariate analysis with a younger age (38 vs. 43 years, P;0.0224), a larger tumour size (60 +/- 6 vs. 46 +/- 2 mm, P=0.0291), an expanding margin (85% vs. 51%, P=0.0159), a higher number of tumour-infiltrating lymphocytes assessed by CD3 immunostaining (202 +/- 48 vs. 33 +/- 4 CD3+ lymphocytes/10 high-power fields, P=0.0039), and a grade 2 Crohn's like lymphoid reaction (70% vs. 9%, P=0.0037). The two groups were not different for tumour site, differentiation, pTNM stage, vascular and perineural invasion, peripheral adenomatous residue, and 5-year survival rates. CONCLUSIONS: MLH1- or MSH2-deficient colorectal carcinomas of young patients exhibit pathological and molecular features similar to hereditary non-polyposis colorectal cancer. This suggests that MLH1 and MSH2 immunohistochemistry is valuable for detecting hereditary non-polyposis colorectal cancer in young patients.

Adaptor Proteins, Signal Transducing↗

Expression of p53 protein in T- and natural killer-cell lymphomas is associated with some clinicopathologic entities but rarely related to p53 mutations.

To determine if p53 abnormalities could be involved in the pathogenesis of T- or natural killer (NK)-cell lymphomas, we investigated 51 cases of these lymphomas for the expression of p53 and its relationship with p53 gene mutations, the expression of the p21 protein as well as the proliferative and apoptotic indices. Overexpression of p53 was found in 19 cases (37%), whereas mutations of the p53 gene were observed in only 5 of 28 tested cases. The analysis of immunohistochemical data showed some entity-related phenotypic profiles. Anaplastic large cell lymphomas showed a frequent overexpression of p53 (7/8 cases) and p21 (6/8 cases) proteins and rare p53 mutations (1/7 cases), suggesting accumulation of a functional wild type p53 protein able to induce p21 expression. Nodal peripheral T-cell lymphomas unspecified showed relatively frequent overexpression of p53 protein (5/7 cases), infrequent p21 expression (2/7 cases), and rare p53 gene mutations (1/6 cases). In angioimmunoblastic lymphomas, the common phenotype was p53-/p21- (15/17 cases), with only a few scattered p53-positive cells, which, on the basis of double staining results, were mostly Epstein-Barr virus-infected B cells. A p53 gene mutation was only found in 1 case (1/8 cases) of angioimmunoblastic lymphoma, which showed cytologic tumor progression. Mycosis fungoides showed p53 overexpression in 2 of 4 cases, including 1 case with p53 gene mutation and features of cytologic tumor progression. Nasal NK/T lymphomas showed p53 overexpression in 2 of 5 cases, 1 of which had a p53 gene mutation. Finally, all lymphoblastic T-cell lymphomas (5 cases) and gammadelta hepatosplenic T-cell lymphomas (3 cases) were negative for expression of p53 and p21 proteins. We conclude that p53 protein overexpression is a common finding in some entities of T- and T/NK-cell lymphomas, whereas a p53 gene mutation is a rare, sporadic, and rather late event associated with tumor progression in some instances. The p53/p21 expression pattern appears to be variable in T- and T/NK-cell lymphoma entities, reinforcing the concept of distinct, entity-related mechanisms of pathogenesis in these tumors.

Adolescent↗

[Epidural non-Hodgkin's lymphoma presenting as a spinal cord compression].

OBJECTIVE AND METHODS: epidural localization is a rare presenting sign of non Hodgkin's lymphoma. In this study, we describe the clinical, histological and immunohistochemical data in 13 cases (9 men and 4 women) of non-Hodgkin's lymphoma with epidural involvement. RESULTS: the median age was 63 years (range 36-76 years). Clinically, most patients complained of back pain (median duration, 3.4 months) followed by acute neurological deterioration. In 10 out of 13 tumors, a thoracic localization was observed and a decompressive laminectomy was performed in all cases. Histology and immunohistochemistry showed all tumors to be B-cell lymphomas which were classified as: lymphocytic lymphoma (3 cases), prolymphocytic lymphoma (1 case), follicular lymphoma (2 cases), diffuse large cell lymphoma (6 cases) and AIDS associated Burkitt lymphoma (1 case). Post-operative staging revealed bone and/or paravertebral involvement in 11 cases and disseminated disease in 5 cases. Median survival following complementary therapy, radiotherapy and chemotherapy in most cases, was 20 months. CONCLUSION: histological features of epidural lymphomas are similar to other extranodal lymphomas and their prognosis is better than other epidural neoplasms, especially when the tumor is localized.

Adult↗

Influence of light additional arm cranking exercise on the kinetics of VO2 in severe cycling exercise.

This study examined the influence of light additional arm cranking exercise on the VO2 slow component observed during severe cycling exercise. During incremental tests, eleven triathletes exercised to exhaustion cycling with leg, cranking with arm and combined arm and leg cranking and cycling (arm work-rates being set at the third of leg work rates) to determine arm, leg and combined arm and leg lactate threshold and VO2max. After these incremental tests subjects performed in random order severe exercises until exhaustion at work-rates corresponding to the lactate threshold + 50% of the difference to the work rate associated with VO2max and the lactate threshold, i.e., delta50: 1) with legs only (leg delta50) 2) leg delta50 plus a very light arm cranking exercise at 25 % of the arm lactate threshold (Ldelta50 + A25). VO2 slow component was the increase of VO2 (in ml x min(-1)) between the third and the sixth minute of exercise (deltaVO2 63 min). Results showed 1) Nine of the eleven triathletes had a VO2 slow component in arm delta50; 2) a light cycle arm exercise (25% of lactate threshold) added to a severe leg cycle exercise did not decrease time to exhaustion in severe exercise (493 +/- 154s vs 418 +/- 84, P=0.4); 3) For the five subjects who had a VO2 slow component in leg cycling, the addition of a light arm exercise (25% of arm LT) decreased the VO2 slow component significantly (from 457 +/- 173 ml x min(-1) for leg delta50 to 111 +/- 150 ml x min(-1) for Ldelta50 + A25, Z = -2.0, P = 0.04). In conclusion, light additional arm cranking decreases the VO2 slow component in severe cycling. Further studies are needed to confirm the hypothesis that extra work due to an increasing handgrip on the handlebars may contribute to the VO2 slow component in cycling.

Adult↗

Calculation of times to exhaustion at 100 and 120% maximal aerobic speed.

The aim was to compare physiologic responses during exhaustive runs performed on a treadmill at 100 and 120% maximal aerobic speed (MAS: the minimum speed that elicits VO2max). Fourteen subelite male runners (mean +/- SD; age = 27+/-5 years; VO2max = 68.9+/-4.6 ml/kg(-1)/min(-1); MAS = 21.5+/-1 km/h(-1)) participated. Mean time to exhaustion tlim100% at 100% MAS (269+/- 77s) was similar to those reported in other studies. However, there was large variability in individual tlim100% MAS (CV = 29%). MAS was positively correlated with VO2max (r = 0.66, p<0.05) but not with tlim100%) MAS (r = -0.50, p<0.05). tlim100% MAS was correlated with t(lim) at 120% MAS (r = 0.52, p < 0.05) and to blood pH following the rest at 120% MAS (r = -0.68, p<0.05). The data suggest that running time to exhaustion at MAS in subelite male runners is related to time limit at 120% (tlim120%) MAS. Moreover, anaerobic capacity determined by the exercise to exhaustion at 120% MAS can be defined as the variable 'a' in the model of Monod and Scherrer (1954).

Adult↗

Expression of cytotoxic proteins in peripheral T-cell and natural killer-cell (NK) lymphomas: association with extranodal site, NK or Tgammadelta phenotype, anaplastic morphology and CD30 expression.

Most peripheral T-cell lymphomas (PTCL) express the alphabeta T-cell receptor (TCR) whereas rare PTCL express the gammadelta TCR. Most if not all gammadelta PTCL are extranodal lymphomas and among them, hepatosplenic gammadelta PTCL constitute a distinct clinicopathological entity. Besides alphabeta and gammadelta PTCL, there is a recently recognized group of extranodal, mainly nasal tumours, which display, in most instances, phenotypic and genotypic features of Natural-Killer cell non-Hodgkin's lymphomas (NK-NHL). Cytotoxic cells, including NK cells and cytotoxic alphabeta and gammadelta T lymphocytes may induce lysis of the target by using granule-associated cytotoxic proteins such as the T-cell intracellular antigen-1 (TIA-1), perforin and granzyme B. Expression of TIA-1 can be detected in all cytotoxic cells whereas granzyme B and perforin expression can be detected in high levels only in activated cytotoxic cells. Recently, several studies showed that the expression of these cytotoxic proteins in tumour cells of PTCL and NK-NHL is associated with a) extranodal site of clinicopathological presentation b) NK or Tgammadelta-cell phenotype c) CD30 expression in cutaneous T-cell lymphoproliferations and d) anaplastic morphology in nodal PTCL. This latter finding contrasts with the data that only rare Hodgkin lymphomas (HL) express cytotoxic proteins in Hodgkin and Reed-Sternberg cells. Altogether the data of the literature indicate that most extranodal T and NK-NHL are activated cytotoxic lymphomas with the notable exception of hepatosplenic gammadelta PTCL which represent tumours of non-activated cytotoxic cells. On this basis, it is suggested that the expression of cytotoxic proteins may be useful for the identification and classification of extranodal T and NK-cell lymphomas and, to some extent, for the differential diagnosis between HL and CD30+ anaplastic large cell lymphomas. Cytotoxic lymphomas are preferentially localized in extranodal sites such as skin, lung, upper respiratory and gastrointestinal tracts, which are continuously exposed to various antigens. Since cytotoxic T and NK cells are regarded as first line of defense in these sites, and some cytotoxic tumours such as nasal lymphomas and enteropathy-type intestinal lymphomas are associated with EBV and gliadin, respectively, it is likely that chronic antigen exposure may play a role in the pathogenesis of cytotoxic lymphomas occurring in mucosa and/or skin. Besides chronic antigenic stimulation, chronic immunosuppression may also have pathogenetic significance in cytotoxic lymphomas in view of their increased incidence in immunocompromised patients.

Antigens, CD↗

[Pancreatic neuroendocrine tumors and von Hippel-Lindau disease].

Pancreatic neuroendocrine tumors are rare in von Hippel-Lindau disease, most often asymptomatic, nonfunctioning, non secreting, and benign. We report a case of low grade malignant pancreatic, secreting and asymptomatic neuroendocrine tumors, occurring in a 27 year old woman in the setting von Hippel-Lindau disease with recurrent pheochromocytoma, retinal and medullary hemangioblastomas, paraganglioma of the carotid body and ovarian cystadenoma. Neuroendocrine pancreatic tumors of von Hippel-Lindau disease are often constituted by clear cells, in the contrary of other neuroendocrine tumors of the pancreas. Occurrence of a pancreatic neuroendocrine tumor, especially in association with pheochromocytoma, may be misdiagnosed with a type 2 multiple endocrine neoplasia syndrom instead of von Hippel-Lindau disease.

Adrenal Gland Neoplasms↗

[External iliac artery endofibrosis of the cyclist].

Arterial endofibrosis is a rare disease usually affecting the external iliac artery in highly trained athletes. We report a case of bilateral external iliac endofibrosis in a 44-year-old cyclist. Microscopic examination of the resection specimen showed an isolated thickening of the arterial intima, and confirmed the diagnosis of this entity of unknown etiology.

Adult↗