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Biomedical subjects

P Babin

Publications and source records attributed to P Babin.

At least 19 recordsLinked to original sources
PubMed2001

[Primary thyroid lymphoma: report of 8 cases].

PURPOSE: Primary thyroid lymphoma (PTL) is a rare disease. Few patients are reported in the literature. We report eight new cases of PTL with long-term follow-up. RESULTS: The clinical presentation was usually an enlarging neck mass squeezing surrounding structures. The diagnosis was established after thyroidectomy with histopathologic and immunohistochemical studies. Histology showed infiltrates of chronic lymphocytic thyroiditis in all cases. Three patients had thyroid lymphoma arising from mucosa-associated lymphoid tissue. One patient died postoperatively. The other seven were treated with combined chemotherapy and radiotherapy. They were still in remission after a 6-year follow-up. CONCLUSION: Diagnosis of PTL should be suspected when there is a recent thyroid enlargement. Surgery associated with chemotherapy and radiation gave good results in our study with long-term follow-up, though surgery was not always recommended in previous reports.

Adult↗
PubMed2001

Ultrastructural study of rat hippocampus after chronic administration of aluminum L-glutamate: an acceleration of the aging process.

An ultrastructural study of rat hippocampus was performed on young (group 1) and old (group 4) rats receiving daily subcutaneous injections of aluminum L-glutamate and on old untreated rats (group 5). Young controls were treated with sodium L-glutamate (group 2) and physiological saline (group 3). Group 1 showed vacuolated astrocytes with numerous lipofuscin deposits, mitochondrial swelling, a thinning of the myelin sheath, and many multivesicular bodies invading the cytoplasm. Cellular structure did not appear to be affected in groups 2 and 3. Group 4 showed swollen mitochondria, a demyelination process in axonal regions, sizable perivascular oedema with vessel retraction and gliofilament bundles. In this group, lipofuscin deposits in astrocytes were associated with multivesicular bodies that thinned the myelin sheath to the breaking point; however, no excitotoxic glutamate-induced effects were observed. In group 5, extreme cytoplasmic vacuolation was observed, with massive mitochondrial swelling, considerable thinning of the myelin sheath (at times to the breaking point), sizable vacuolar degeneration and gliofilament bundles. These results indicate that ultrastructural alterations in the hippocampus, such as cell vacuolization, massive mitochondrial swelling and the demyelination process, occur with aging and independently of aluminum intoxication. Similar alterations were observed in aluminum L-glutamate-intoxicated young rats, but not in controls. These results are consistent with aluminum-induced acceleration of the aging process.

Aging↗
PubMed2001

Construction and analysis of base-paired regions of the 16S rRNA in the 30S ribosomal subunit determined by constraint satisfaction molecular modelling.

Structure models for each of the secondary structure regions from the Escherichia coli 16S rRNA (58 separate elements) were constructed using a constraint satisfaction modelling program to determine which helices deviated from classic A-form geometry. Constraints for each rRNA element included the comparative secondary structure, H-bonding conformations predicted from patterns of base-pair covariation, tertiary interactions predicted from covariation analysis, chemical probing data, rRNA-rRNA crosslinking information, and coordinates from solved structures. Models for each element were built using the MC-SYM modelling algorithm and subsequently were subjected to energy minimization to correct unfavorable geometry. Approximately two-thirds of the structures that result from the input data are very similar to A-form geometry. In the remaining instances, the presence of internal loops and bulges, some sequences (and sequence covariants) and accessory information require deviation from A-form geometry. The structures of regions containing more complex base-pairing arrangements including the central pseudoknot, the 530 region, and the pseudoknot involving base-pairing between G570-U571/A865-C866 and G861-C862/G867-C868 were predicted by this approach. These molecular models provide insight into the connection between patterns of H-bonding, the presence of unpaired nucleotides, and the overall geometry of each element.

Base Pairing↗
PubMed2001

Cadmium-containing granules in kidney tissue of the Atlantic white-sided dolphin (Lagenorhyncus acutus) off the Faroe Islands.

Top predators from the northern sub-polar and polar areas exhibit high cadmium concentrations in their tissues. In the aim to reveal possible adverse effects, samples of five Atlantic white-sided dolphins Lagenorhyncus acutus have been collected on the occasion of the drive fishery in the Faroe Islands, for ultrastructural investigations and energy dispersive X-ray microanalyses. Cadmium concentrations were less than the limit of detection in both immature individuals and ranged from 22.7 to 31.1 microg x g(-1) wet weight in the mature individuals. Two individuals with the highest cadmium concentrations exhibited electron dense mineral concretions in the basal membranes of the proximal tubules. They are spherocrystals made up of numerous strata mineral deposit of calcium and phosphorus together with cadmium. Cadmium has been detected with a molar ratio of Ca:Cd of 10:1 in the middle of these concretions. To our knowledge, this is the first report of such granules in a wild vertebrate. The role of these granules in the detoxification of the metal and the possible pathological effects are considered.

Animals↗
PubMed2001

[Pigmented Paget's disease of the male nipple].

BACKGROUND: Mammary Paget's disease unfrequently occurs in males, and may be pigmented in rare instances. Differential diagnosis with malignant melanoma relies on immunohistochemical studies. CASE REPORT: A case of Paget's disease of the nipple in a 76 year-old male is reported, clinically mimicking a malignant melanoma because of massive pigmentation. Histologically, large Paget's clear cells were intermingled with numerous melanin-rich dendritic melanocytes. An underlying ductal carcinoma was found. After differential immunohistochemical staining, diagnosis of Paget's disease could be unequivocally substantiated since Paget's cells stained for epithelial markers, c-erbB-2 and hormonal receptors, whereas protein S100 and HMB45 were negative. DISCUSSION: Pigmentation in mammary Paget's disease occurs preferentially in males. Pigmentation results from numerous melanocytes with abundant melanin in close contact with Paget's cells. An increased number of melanocytes may also be observed in cutaneous metastatic breast carcinomas. It could result from a chemotactic factor produced by neoplastic cells.

Aged↗
PubMed2001

[Mixed type amyloidomas, beta2 microglobulin and AL lambda, in a long term hemodialysis patient].

A frequent complication of hemodialysis is deposition of beta 2-microglobulin amyloid in tendons and joints. Soft tissues involvement is exceptional. A 74 year-old woman on hemodialysis for 21 years developed two bilateral and symmetric tumours in gluteal regions causing discomfort when sitting. Histology, immunohistochemistry and electron microscopy showed that deposit consisted of predominant beta 2-microglobulin and lambda light chain. This is an unusual localisation of amyloidosis developing late in the course of hemodialysis. It may be perhaps initiated by chronic traumatism and be promoted by the light chain lambda of immunoglobulin.

Adipose Tissue↗
PubMed2000

Initiation factor 3-induced structural changes in the 30 S ribosomal subunit and in complexes containing tRNA(f)(Met) and mRNA.

Initiation factor 3 (IF3) acts to switch the decoding preference of the small ribosomal subunit from elongator to initiator tRNA. The effects of IF3 on the 30 S ribosomal subunit and on the 30 S.mRNA. tRNA(f)(Met) complex were determined by UV-induced RNA crosslinking. Three intramolecular crosslinks in the 16 S rRNA (of the 14 that were monitored by gel electrophoresis) are affected by IF3. These are the crosslinks between C1402 and C1501 within the decoding region, between C967xC1400 joining the end loop of a helix of 16 S rRNA domain III and the decoding region, and between U793 and G1517 joining the 790 end loop of 16 S rRNA domain II and the end loop of the terminal helix. These changes occur even in the 30 S.IF3 complex, indicating they are not mediated through tRNA(f)(Met) or mRNA. UV-induced crosslinks occur between 16 S rRNA position C1400 and tRNA(f)(Met) position U34, in tRNA(f)(Met) the nucleotide adjacent to the 5' anticodon nucleotide, and between 16 S rRNA position C1397 and the mRNA at positions +9 and +10 (where A of the initiator AUG codon is +1). The presence of IF3 reduces both of these crosslinks by twofold and fourfold, respectively. The binding site for IF3 involves the 790 region, some other parts of the 16 S rRNA domain II and the terminal stem/loop region. These are located in the front bottom part of the platform structure in the 30 S subunit, a short distance from the decoding region. The changes that occur in the decoding region, even in the absence of mRNA and tRNA, may be induced by IF3 from a short distance or could be caused by the second IF3 structural domain.

Alkalies↗
PubMed2000

Synthesis of haptens and conjugates for ELISAs of phytoestrogens. Development of the immunological tests.

Seven carboxylic acid haptens of isoflavonoids were synthesized, with the spacer arm on the oxygen atom at the C7 position for one series, with formononetin, daidzein, equol, biochanin A, and genistein, and at the C8 position for a second series, with only formononetin and daidzein. The different haptens were coupled to bovine serum albumin (BSA) and to swine thyroglobulin (Thyr). Polyclonal antibodies were generated against the BSA conjugates. Enzyme-linked immunosorbent assays (ELISAs) were developed based on competition between free phytoestrogens and the Thyr-hapten conjugates for specific antibodies. IC(50) values of the standard curves ranged between 0.8 and 20 ng/mL that is, 0.3 and 9.2 pmol/well. The antibodies obtained should be useful for assays in vegetable matter as well as in biological fluids after a separation step. These ELISAs should be valuable also in the food industry to control phytoestrogen concentrations prior to and after processing.

Animals↗
PubMed1999

Effects of tetracycline and spectinomycin on the tertiary structure of ribosomal RNA in the Escherichia coli 30 S ribosomal subunit.

Structural analysis of the 16 S rRNA in the 30 S subunit and 70 S ribosome in the presence of ribosome-specific antibiotics was performed to determine whether they produced rRNA structural changes that might provide further insight to their action. An UV cross-linking procedure that determines the pattern and frequency of intramolecular 16 S RNA cross-links was used to detect differences reflecting structural changes. Tetracycline and spectinomycin have specific effects detected by this assay. The presence of tetracycline inhibits the cross-link C967xC1400 completely, increases the frequency of cross-link C1402x1501 twofold, and decreases the cross-link G894xU244 by one-half without affecting other cross-links. Spectinomycin reduces the frequency of the cross-link C934xU1345 by 60% without affecting cross-linking at other sites. The structural changes occur at concentrations at which the antibiotics exert their inhibitory effects. For spectinomycin, the apparent binding site and the affected cross-linking site are distant in the secondary structure but are close in tertiary structure in several recent models, indicating a localized effect. For tetracycline, the apparent binding sites are significantly separated in both the secondary and the three-dimensional structures, suggesting a more regional effect.

Anti-Bacterial Agents↗
PubMed1999

Chronic administration of aluminium L-glutamate in young mature rats: effects on iron levels and lipid peroxidation in selected brain areas.

Clinical and experimental studies have demonstrated the neurotoxicity of aluminium (Al), notably as a result of lipid peroxidation in vitro. We previously showed that Al is able to cross the blood-brain barrier as an L-glutamate complex and be deposited in rat brain. The present work in young mature rats investigated the in vivo effects of chronic Al-L-glutamate treatment on Al and iron movement in plasma and selected brain regions. Brain lipid peroxidation was determined by evaluating the production of thiobarbituric acid reactive substances (TBARS) and analysing polyunsaturated fatty acids (PUFAs) such as C20:4n-6 and C22:6n-3. Our results indicate that iron concentration was decreased in plasma and that Al accumulated especially in striatum where iron levels were decreased and in the hippocampus where TBARS were increased without PUFA modifications. These data show that Al administered chronically as an L-glutamate complex is neurotoxic in vivo and thus provides a good model for studying Al toxic mechanisms.

Aluminum↗
PubMed1999

Histological evaluation of proximal tubule cell injury in isolated perfused pig kidneys exposed to cold ischemia.

BACKGROUND: Ischemic injury of the renal allograft before transplantation is a major cause of impaired graft function. Proton nuclear spectroscopy provides a useful technique for evaluating proximal tubular activity. In addition to this technique, we proposed a histological grading system for quantifying proximal tubule alterations. METHODS: The aim of this study was to evaluate the histological lesions of tubule epithelial cells in the model of isolated perfused pig kidneys following 48 to 72 h of cold storage in Euro-Collins solution. Normothermic isolated perfused pig kidneys were randomized in three experimental groups : Group 1, control group; cold flush with cold heparinized solution followed by immediate reperfusion (n = 6); Group 2, 48 h of cold storage in Euro-Collins followed by reperfusion (n = 6); Group 3, 72 h of cold storage in Euro-Collins followed by reperfusion (n = 6). Proton nuclear spectroscopy of urine and biochemical studies were performed for whole renal functional evaluation during reperfusion. Optical and electron microscopy analyses of the reperfused kidneys were performed by four investigators and the degree of cell injury was assessed using 8 different criteria in a 5-scale numerical score. RESULTS: Numerical scores corroborate the results from NMR spectroscopy and differed significantly between the three groups studied. The degree of proximal tubule cell damage was increased with prolonged cold ischemia as shown particularly in Group 3. CONCLUSION: The results from this study showed that analysis of cell injury based on an histological grading system in the model of isolated perfused kidney allows the quantification of the degree of proximal tubule injury. Thus, such morphological system analysis could be a useful method for quantifying tubule cell injuries observed under various physiopathological conditions.

Animals↗
PubMed1999

Identity and geometry of a base triple in 16S rRNA determined by comparative sequence analysis and molecular modeling.

Comparative sequence analysis complements experimental methods for the determination of RNA three-dimensional structure. This approach is based on the concept that different sequences within the same gene family form similar higher-order structures. The large number of rRNA sequences with sufficient variation, along with improved covariation algorithms, are providing us with the opportunity to identify new base triples in 16S rRNA. The three-dimensional conformations for one of our strongest candidates involving U121 (C124:G237) and/or U121 (U125:A236) (Escherichia coli sequence and numbering) are analyzed here with different molecular modeling tools. Molecular modeling shows that U121 interacts with C124 in the U121 (C124:G237) base triple. This arrangement maintains isomorphic structures for the three most frequent sequence motifs (approximately 93% of known bacterial and archaeal sequences), is consistent with chemical reactivity of U121 in E. coli ribosomes, and is geometrically favorable. Further, the restricted set of observed canonical (GU, AU, GC) base-pair types at positions 124:237 and 125:236 is consistent with the fact that the canonical base-pair sets (for both base pairs) that are not observed in nature prevent the formation of the 121 (124:237) base triple. The analysis described here serves as a general scheme for the prediction of specific secondary and tertiary structure base pairing where there is a network of correlated base changes.

Base Pairing↗
PubMed1999

High-dose chemotherapy with hematopoietic stem cell transplantation in adults with bone marrow relapse of medulloblastoma: report of two cases.

Extraneural relapses of medulloblastoma are associated with a very poor outcome. We present two cases of young adults who developed bone marrow metastases after treatment of medulloblastoma. A very good response to a sequentially scheduled combination of carboplatin and etoposide was observed. Then, high-dose chemotherapy was delivered consisting of busulfan and thiotepa followed by infusion of autologous hematopoietic stem cells. Toxicity of the conditioning regimen was acceptable. The patients remained free of disease 20 and 27 months from the time of relapse, respectively. Further studies are needed to evaluate the impact of high-dose chemotherapy in terms of survival of such patients.

Adult↗
PubMed1999

[Alveolar adenoma: a rare peripheral pulmonary tumor].

Alveolar adenoma was first described in 1986. It is a benign peripheral lung neoplasm present more frequently in middle-aged woman. We report a new case occurring in 52 year-old woman. We describe histopathological and immunohistochemical characteristics. Then, this observation is compared with the 11 cases previously published. Finally, we try to understand its origin.

Adenoma↗
PubMed1999

[Multiple vulvar cystic and papillary fibroadenomas].

We report a new case of multiple vulvar fibroadenoma arising in a 47-year-old woman. This papillary and cystic lesion shares similarities with papilliferum hidradenoma and mammary fibroadenomas. After describing clinical and pathological characteristics, we try to detail its origin according to the literature and particularly its relationship with anogenital sweat glands and ectopic mammary glands.

Female↗
PubMed1998

The naevoid basal-cell carcinoma syndrome (Gorlin syndrome) is a chromosomal instability syndrome.

The Gorlin syndrome, or naevoid basal-cell carcinoma syndrome (NBCS) is an autosomal dominant cancer prone disease (at risk of multiple basal cell carcinomas, and other malignant or benign proliferations). We have previously reported data from peripheral blood lymphocytes of patients with this condition, showing a significant level of spontaneous chromatid and chromosome rearrangements and an overall lengthening of the cell cycle. In this paper, we confirm this disease to be a chromosome instability syndrome from studies on fibroblasts of 5 patients. Spontaneous chromosomal rearrangements, an increased frequency of sister chromatid exchanges and a slowing of the cell cycle were found, compared to age-matched control material. There was also an increased sensitivity to aberration production by mechlorethamine in patient fibroblasts. The chromosome instability we found was not restricted to a given cell lineage, but appears to be part of the general condition of this syndrome. The recently discovered gene responsible for Gorlin syndrome, PTC (or PTCH), encodes a transmembrane protein with yet poorly known functions. However, the demonstration of Gorlin syndrome as a chromosome instability syndrome suggests that this protein has a role in DNA maintenance, repair and/or replication.

Basal Cell Nevus Syndrome↗
PubMed1998

[Papillary fibroelastoma. A rare etiology of strokes in young patients].

BACKGROUND: The papillary fibroelastomas are cardiac lesions, which typically occur on the cardiac valves, but rarely on the endocardium. The incidence of these benign primitive tumors varies from 0.002 to 0.33% and increases with advancing age. METHODS: We report two cases of stroke, one in a 31-year-old man and the other in a 48-year-old woman, both admitted to the same stroke center. RESULTS: The diagnostic studies were normal in these two patients, except for the echocardiography. The first showed an echogenic mass on the mitral valve on transthoracic echocardiography (TTE), confirmed by the transesophageal echocardiography (TEE). The second demonstrated a mass on the sigmoid aortic valve on TEE, but the TTE was normal. For these two patients, a surgical excision was carried out and pathologic examination concluded to a papillary fibroelastoma. After surgery, no recurrence was observed. CONCLUSIONS: The papillary fibroelastomas are usually asymptomatic and easily detected by TEE. However, it can be revealed by stroke, myocardial infarction and lower limbs ischemia. These cardiac tumors should be surgically removed, since their complete excision remains the only means of avoiding a recurrence of embolism.

Adult↗