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Biomedical subjects

A Volant

Publications and source records attributed to A Volant.

At least 19 recordsLinked to original sources
PubMed1999

Loss of heterozygosity at chromosome arm 13q and RB1 status in human prostate cancer.

Aberrations of the long arm of chromosome 13 are common in prostate cancer and were initially attributed to alterations of the RB1 gene in band q14 of the chromosome. However, prostate tumors generally yield normal p110RB1 nuclear staining despite loss of heterozygosity (LOH) at the RB1 locus. Our previous analysis of chromosome arm 13q showed allelic loss in 41% of primary prostate tumors. To refine our knowledge of 13q, we extended our previous LOH study by using more polymorphic markers to analyze more prostate tumors. Sixty human prostate carcinomas were screened for allelic loss on 13q by using 13 13q-specific markers. LOH on the long arm of chromosome 13 was found in 39 (65%) of the 60 tumors. Furthermore, 33 of these 39 tumors had evidence of allelic loss involving a region of 13q14 containing RB1. Because immunohistochemical assessment of pRb expression is controversial in prostate tumors, we used a quantitative reverse transcription polymerase chain reaction (RT-PCR) method to determine whether RB1 is the target tumor suppressor gene in this region. RB1 mRNA steady-state levels were determined in 12 prostate tumors preselected on the basis of presumed deletion at the RB1 locus and four prostate tumors without LOH at the RB1 locus; five normal prostate specimens were used as controls. One of the 12 assessable prostate tumors with presumed LOH at RB1 showed a corresponding decreased in RB1 mRNA expression, whereas none of the four tumors without LOH at RB1 locus showed such a decrease. This study, based on another technical approach, confirms that RB1 is not the main target of the observed LOH at 13q14.3, and raises the possibility that another tumor suppressor gene in this region plays a key role in prostate cancer.

Chromosomes, Human, Pair 13↗
PubMed1998

[Diagnosis of mediastinal neuro-endocrine tumor using endosonography guided transesophageal puncture biopsy].

Histologic diagnosis of tumors of the mediastinum is mandatory for therapeutic management. The location and the variety of tumors are responsible for diagnostic difficulties. Endosonography guided fine-needle biopsy is an efficient and safe procedure for the diagnosis of peridigestive masses. We report the case of a patient with a neuroendocrine tumor of the mediastinum revealed by a mass syndrome. The diagnosis was performed by endosonography guided needle biopsy.

Biopsy, Needle↗
PubMed1997

[Is there a role for Excimer laser in the treatment of keratoconus?].

PURPOSE: In advanced keratoconus, when contact lenses become intolerant or provide insufficient vision, the only current available treatment is penetrating keratoplasty. But getting a graft takes a long time; we evaluated the eventual role of Excimer laser in taking care of those patients. MATERIAL AND METHODS: We present a series of 8 advanced keratoconus, at that time, intolerant to contact lens because of a major ectasia and/or apical opacities. An excimer photoablation, using the therapeutic or rarely the refractive one, was performed in order to flatten or resurface the cornea, allowing a new contact lens fitting. RESULTS: We noted no complication, except a denser and longer postoperative haze. Thanks to a good compliance, 4 patients benefited from a new contact lens fitting, leading to an optimal visual recovery. On the other hand, in 3 cases, a corneal graft had to be performed, without any side effect. An anatomo-pathologic analysis was achieved on the 3 corneal caps, giving some precisions about tissular changes. CONCLUSION: Excimer laser, under its therapeutic approach, might be an efficient treatment for advanced keratoconus, in conditions of cautious indications selection and of an inevitable coupling to contactology. Then, this surgery could delay or even avoid penetrating keratoplasty.

Adult↗
PubMed1996

Preoperative concomitant radiochemotherapy in squamous cell carcinoma of the esophagus: results of a study of 56 patients.

PURPOSE: Today the prognosis for patients with esophageal carcinoma still remains quite poor. In the last few years interesting results have been obtained by associating radio- and chemotherapy with or without surgery with this type of cancer. In this work we report the results of concomitant radio- and chemotherapy in a split-course schedule preceeding surgery for the treatment of squamous cell carcinomas of the esophagus. METHODS AND MATERIALS: Fifty-six patients with squamous cell carcinomas of the esophagus were treated between April 1989 and September 1993 in the Centre Hospitalier Universitaire in Brest, France with two courses of preoperative concomitant radiochemotherapy, separated by a 2-week interval, and followed by surgery (each course 18.5 Gy in five fractions, days 1-5 with continuous infusion 5-fluorouracil (5-FU) 800 mg/m2 days 1-5 and cisplatinum 70 mg/m2 day 2). Patients who had responded well to preoperative treatment (response > 50%) received four more courses of chemotherapy alone. The two patients who were not operated and those with palliative surgery received a third course of radiochemotherapy (radiotherapy 12 Gy in five fractions, days 1-5). RESULTS: Fifty-four patients were operated on. Twenty-one showed histological complete response at surgery (37.5% of the whole group). Actuarial survival for the 56 patients was 55% at 3 years and 30% at 4 years, with a median survival of 37.4 months (40.4 months for complete responders to preoperative treatment). Toxicity of preoperative concomitant radio-chemotherapy was low (5-FU had to be stopped in one patient because of cardiac rythm disturbances and in another patient because of aplasia Grade 4 associated with infection after the first course). Postoperative mortality was 11% (six patients). CONCLUSION: This combination of preoperative radiochemotherapy followed by surgery seems to improve both response rates and survival in patients with esophageal cancer when compared with previous patients treated with surgery alone in our hospital or with results found in literature and it warrants further studies.

Aged↗
PubMed1996

Molecular analysis of the TP53 gene in Barrett's adenocarcinoma.

The TP53 gene is the most frequently mutated gene in human cancers. Barrett's esophagus provides an excellent model by which to understand the genetic events that lead from dysplasia to cancer. We screened for mutations in the TP53 gene by a combination of denaturing gradient gel electrophoresis and DNA sequencing in ten cases of adenocarcinoma arising in Barrett's mucosa. We have identified missense mutations in five of the ten samples, three transitions (R282W, G245S, R248W) and two transversions (E286Q and C176F). In one case we have analyzed biopsy specimens taken from the same site, one year before the patient developed an intra mucosal carcinoma. The mutation that was identified in this high grade dysplastic area was identical to that detected in the cancer. This would suggest TP53 mutations occur as an early genetic event in the development of Barrett's adenocarcinoma.

Adenocarcinoma↗
PubMed1996

Nephrogenic adenoma of the bladder in renal transplant recipients: a report of 9 cases with assessment of deoxyribonucleic acid ploidy and long-term followup.

PURPOSE: We evaluated the outcome of nephrogenic adenoma, a benign tumor rarely encountered in renal transplant recipients. MATERIALS AND METHODS: Between 1985 and 1993, 9 renal transplant recipients with a nephrogenic bladder adenoma removed by endoscopic resection were followed for 24 to 88 months (mean 40). Tumor deoxyribonucleic acid ploidy was assessed by flow cytometry at diagnosis and/or relapse. RESULTS: The relapse rate was 88%. The tumors were diploid and of low proliferating potential, and showed no malignant transformation. CONCLUSIONS: Our study confirms the lack of premalignant potential of nephrogenic adenomas. However, since transplant recipients might be at increased risk for bladder cancer, they should be followed closely.

Adenoma↗
PubMed1995

Gene amplifications in advanced-stage human prostate cancer.

Gene amplification is a model of proto-oncogene alterations occasionally observed in human tumors. This amplification can, in some cases, have prognostic value (N-myc in neuroblastoma, c-erbB2 and int-2 in breast cancer, etc.). Amplifications of the proto-oncogenes c-myc, c-erbB2 and int-2 have not yet been report in prostate adenocarcinoma, which, like breast cancer, is hormone dependent. We sought amplifications of these three proto-oncogenes by means of Southern blotting in 15 human prostate adenocarcinoma specimens, most of which were advanced (7 stage C and 6 stage D1 or D2). We confirmed the lack of c-myc and c-erbB2 amplification, regardless of the stage, in contrast to the case of breast cancer. Int-2 amplification was observed in one advanced tumor with bone metastases, out of a total of six stage D tumors. The precise frequency of int-2 amplification and its role in prostate carcinogenesis remain to be determined.

Adenocarcinoma↗
PubMed1995

p53 protein accumulation in oesophageal squamous cell carcinomas and precancerous lesions.

AIMS: To investigate the immunohistochemical expression of p53 protein in oesophageal squamous cell carcinomas and in dysplastic areas of the oesophageal mucosa surrounding the tumours. METHODS: Biopsy samples were obtained from 20 patients with an oesophageal squamous cell carcinoma. Blocks of the tumours and of the surrounding mucosa were immunostained with the monoclonal antibody DO-7. RESULTS: Fourteen of the 20 carcinomas were positive for p53 (70%). The frequency of p53 overexpression increased with the differentiation of the tumour. Nine out of 13 dysplastic specimens were positive for p53 (69%): eight cases with severe dysplasia and one case with moderate dysplasia. No p53 immunostaining was detected in normal oesophageal epithelium. All p53 positive dysplastic specimens were taken from the mucosa adjacent to tumours that were also immunostained. In moderate dysplastic mucosa the p53 positive cells were located in the proliferative basal zone, whereas in severe dysplasia the immunostained cells increased in number and spread to upper cell layers of the epithelium. CONCLUSION: This study supports the hypothesis that TP53 gene is frequently involved in the development of oesophageal squamous cell carcinoma and that p53 protein accumulation is an early event in human oesophageal carcinogenesis.

Adult↗
PubMed1995

Cytochrome P-450 2E1 in rat liver, kidney and lung microsomes after chronic administration of ethanol either orally or by inhalation.

In this study, microsomal cytochrome P-450 2E1 (CYP2E1) contents and activities were tested in liver, kidney and lung from Wistar rats after the following treatments (1) oral administration of a 10% ethanol solution for 4 weeks; (2) pair fed controls; (3) oral administration of a 5% acetone solution for 1 week; (4) inhalation of ethanol vapour for 4 weeks. CYP2E1 activity was measured using chlorzoxazone as substrate and CYP2E1 content was measured using Western blot analysis. In addition, the cellular distribution of CYP2E1 was studied in liver, lung and kidney by immunohistochemistry. Basal liver CYP2E1 was 10-20 times lower in lung and kidney than in liver. Inhalation was clearly the most efficient way of inducing CYP2E1, probably due to the continuous and high alcohol exposure. Among the organs tested, lung appeared to be the tissue least sensitive to induction even after ethanol inhalation, suggesting the absence of local induction. After ethanol intoxication, immunostaining was increased in the centrilobular region of the liver, in the alveolar cells of the lung and in the proximal convoluted tube of the kidney. The CYP2E1 activities decreased to control values in the three tissues tested, within 24 h after cessation of intoxication.

Administration, Inhalation↗
PubMed1995

[Overexpression of protein p53 and Barrett esophagus. A frequent and early event in the course of carcinogenesis].

OBJECTIVES AND METHODS: In Barrett's oesophagus, the risk of malignancy is evaluated histologically with the presence of dysplasia. The abnormal expression of p53 protein could represent a useful new marker. The aim of this study was evaluate the abnormal expression of p53 protein in a series of 52 oesophagectomy specimens with Barrett's oesophagus, either non-dysplastic (n = 3), dysplastic (n = 8), or malignant (n = 41). The immunohistochemical study was made on deparaffinized sections with the monoclonal anti-p53 antibody DO7. RESULTS: The 3 non-dysplastic cases were p53 negative; 1 case of low-grade dysplasia in 5 was positive, as were the 3 cases of high grade dysplasia and 33 of 41 cancers (80%), including 13 superficial cancers in 14 (93%) and 20 invasive cancers in 27 (74%). A common feature was the presence of rare p53 positive crypts in low grade dysplastic areas and non-dysplastic specialized mucosa that surrounded high grade dysplasia and cancers. CONCLUSIONS: Our results confirm the high frequency of the abnormal expression of p53 protein in cancer developed in Barrett's oesophagus. This expression is a consequence of alterations of the TP53 gene, and has an important role in the carcinogenesis of Barrett's mucosa; it is likely to represent an early event. Prospective studies are needed to evaluate its interest in the surveillance of patients with Barrett's oesophagus.

Barrett Esophagus↗
PubMed1994

[Flow cytometry and digestive pathologies].

Flow cytometry provides rapid evaluation of nuclear DNA content and cell cycle analysis. The major applications of flow cytometry in gastroenterology are the evaluation of DNA content and proliferative indices as prognostic indicators of gastrointestinal malignancies, and the screening of premalignant conditions of the digestive tract.

Digestive System Diseases↗
PubMed1994

[Prenatal diagnosis of congenital cystic adenomatoid malformation of lung: perinatal management. Apropos of 4 cases].

BACKGROUND: Cystic adenomatoid malformation of the lung can be seen by ultrasonography during pregnancy. Surgical excision of the affected lobe is indicated during the first days of life. CASES REPORT: Four neonates were admitted to an intensive care unit from March 1988 to February 1992, due to cystic adenomatoid malformation of the lung, that had been diagnosed by ultrasonography at 19, 22, 34 and 37 weeks of gestational age, respectively. These malformations were not associated with other abnormalities and were type I (three cases) and II (one case) according to Stocker's classification. Only one patient became symptomatic, requiring intubation by 72 hours of age. Surgical excision of the affected lobe was performed in three patients at 4 hours, 2 and 7 days of life, respectively, with a normal long-term survival. A segmental resection was performed at 5 days of life in the remaining symptomatic patient but persistence of cystic lesions required lobectomy at 10 months. CONCLUSIONS: Early perinatal management of cystic adenomatoid malformations of the lung is necessary as surgical excision is indicated as soon as possible, even in asymptomatic patients.

Cystic Adenomatoid Malformation of Lung, Congenita↗
PubMed1994

[Cavernous hemangioma of the spleen: values and limitations of ultrasonic and computed tomographic diagnosis].

A case of a cavernous haemangioma associated with an hepatic haemangioma is reported. It presented in the form of a hyperechogenic mass on ultrasound imaging. On the Computed Tomography scan with contrast, the splenic tumour became progressively hyperdense: this last characteristic is observed in 6 out of 9 cases reported in the literature. MR imaging seems to allow an accurate preoperative diagnosis; nevertheless, splenectomy is often indicated because of the risk of rupture, in which case histological examination removes any doubt concerning an exceptional malignant form.

Female↗