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B Benoit

Publications and source records attributed to B Benoit.

At least 37 records · Page 2Linked to original sources
PubMed1999

The Drosophila poly(A)-binding protein II is ubiquitous throughout Drosophila development and has the same function in mRNA polyadenylation as its bovine homolog in vitro.

The poly(A)-binding protein II (PABP2) is one of the polyadenylation factors required for proper 3'-end formation of mammalian mRNAs. We have cloned Pabp2, the gene encoding the Drosophila homolog of mammalian PABP2, by using a molecular screen to identify new Drosophila proteins with RNP-type RNA-binding domains. Sequence comparison of PABP2 from Drosophila and mammals indicates that the most conserved domains are the RNA-binding domain and a coiled-coil like domain which could be involved in protein-protein interactions. Pabp2 produces four mRNAs which result from utilization of alternative poly(A) sites and encode the same protein. Using an antibody raised against Drosophila PABP2, we show that the protein accumulates in nuclei of all transcriptionally active cells throughout Drosophila development. This is consistent with a general role of PABP2 in mRNA polyadenylation. Analysis of Drosophila PABP2 function in a reconstituted mammalian polyadenylation system shows that the protein has the same functions as its bovine homolog in vitro : it stimulates poly(A) polymerase and is able to control poly(A) tail length.

Amino Acid Sequence↗
PubMed1999

Lymphohematopoietic stem cell engraftment.

Traditional dogma has stated that space needs to be opened by cytoxic myeloablative therapy in order for marrow stem cells to engraft. Recent work in murine transplant models, however, indicates that engraftment is determined by the ratio of donor to host stem cells, i.e., stem cell competition. One hundred centigray whole body irradiation is stem cell toxic and nonmyelotoxic, thus allowing for higher donor chimerism in a murine syngeneic transplant setting. This nontoxic stem cell transplantation can be applied to allogeneic transplant with the addition of a tolerizing step; in this case presensitization with donor spleen cells and administration of CD40 ligand antibody to block costimulation. The stem cells that engraft in the nonmyeloablated are in G0, but are rapidly induced (by 12 hours) to enter the S phase after in vivo engraftment. Exposure of murine marrow to cytokines (IL-3, IL-6, IL-11 and steel factor) expands progenitor clones, induces stem cells into cell cycle, and causes a fluctuating engraftment phenotype tied to phase of cell cycle. These data indicate that the concepts of stem cell competition and fluctuation of stem cell phenotype with cell cycle transit should underlie any new stem cell engraftment strategy.

Animals↗
PubMed1999

Correlates between hematopoiesis and neuropoiesis: neural stem cells.

There are many parallels between the neuropoietic and lymphohematopoietic systems. The lymphohematopoietic stem/progenitor cell system has been extensively characterized, but there are still major questions relating to the definitive stem cell assay, the structure of the system (i.e., hierarchical versus cell cycle-based), and the nature of differentiation (i.e., stochastic versus deterministic). Recent data have established the existence of an epidermal growth factor (EGF)-responsive neural stem cell in adult mice. We have studied these neural progenitor/stem cells in fetal (day 15) and 2-day postnatal mice and established a single-cell progenitor assay and a variety of putative uni-, bi-, and tripotential stem cells that form in response to EGF. Neurospheres are the EGF-responsive neural units that grow in liquid culture, and we have found that cells derived from these neurospheres express a wide array of cytokines and their receptors. This will provide a window on the hemopoietic progenitor system analogous to that created by the description of in vitro growth of clonal hematopoietic progenitors.

Animals↗
PubMed1999

[Advantages of studying the frontal plane of the uterine cavity in 3D ultrasound].

Recently, computer-assisted treatment of echographic images has permitted '3D' reconstruction in gynecology. This is achieved by scanning a given volume containing the organ of interest. Two practical options exist. Some ultrasound probes are equipped with an automatic scanning device while others use manual scanning, electronically normalized or not. Both approaches make possible of an electronic matrix, i.e., a pile of '2D' echographic images. Secondary cuts are possible through the electronic matrix, including plans not normally accessible to ultrasound scanning because of anatomical limitations. One of the secondary cuts most clinically useful is the frontal plan of the uterus. This enables one to visualize the organ lying flat as it is commonly drawn on medical sketches. Studying the frontal plan of the uterus acquired electronically from a 3D matrix improves the visualization of possible interactions between structures such as uterine fibroids and the endometrium. The frontal plan of the uterus also offers marked improvements for studying uterine malformations.

Endometrium↗
PubMed1998

Prognostic factors derived from recursive partition analysis (RPA) of Radiation Therapy Oncology Group (RTOG) brain metastases trials applied to surgically resected and irradiated brain metastatic cases.

PURPOSE: (a) To identify the prognostic factors that determine survival after surgical resection and irradiation of tumors metastatic to brain. (b) To determine if the prognostic factors used in the recursive partition analysis (RPA) of brain metastases cases from Radiation Therapy Oncology Group (RTOG) studies into three distinct survival classes is applicable to surgically resected and irradiated patients. METHOD: The medical records of 125 patients who had surgical resection and radiotherapy for brain metastases from 1985 to 1997 were reviewed. The patients' disease and treatment related factors were analyzed to identify factors that independently determine survival after diagnosis of brain metastasis. The patients were also grouped into three classes using the RPA-derived prognostic parameters which are: age, performance status, state of the primary disease, and presence or absence of extracranial metastases. Class 1: patients < or = 65 years of age, Karnofsky performance status (KPS) of > or =70, with controlled primary disease and no extracranial metastases; Class 3: patients with KPS < 70. Patients who do not qualify for Class 1 or 3 are grouped as Class 2. The survival of these patients was determined from the time of diagnosis of brain metastases to the time of death. RESULTS: The median survival of the entire group was 9.5 months. The three classes of patients as grouped had median survivals of 14.8, 9.9, and 6.0 months respectively (p=0.0002). Age of < 65 years, KPS of > or = 70, controlled primary disease, absence of extracranial metastases, complete surgical resection of the brain lesion(s) were found to be independent prognostic factors for survival; the total dose of radiation was not. CONCLUSION: Based on the results of this study, the patients and disease characteristics have significant impact on the survival of patients with brain metastases treated with a combination of surgical resection and radiotherapy. These parameters could be used in selecting patients who would benefit most from such treatment.

Adult↗
PubMed1998

In vitro fertilization in women over 40 years of age. A study on retrospective data for eight years.

A retrospective (1987-1995), single-center study was conducted to evaluate the IVF success rate in women who were 40 years and over. Controls were randomly selected patients who were 35 years or younger from the same center. The main evaluation criterion was the number of pregnancies initiated in each group and especially the number of full-term deliveries (take-home baby rate). Differences were considered as statistically significant for P < or = 0.05: A total of 194 IVF attempts in women 40 years or over were compared to 209 attempts in the control group. The mean ages of the two groups was 40.9 vs. 29.3 years (P < 0.001). The duration of follicle stimulation was 12.9 vs. 13.1 days (not significant, NS). The number of ampules was 29.6 vs. 29.2 (NS). Serum estradiol levels were 1435.8 vs. 2020.8 pg/ml (P < 0.001). Oocytes: 4.6 vs. 7.3 (P < 0.001). Embryos: 1.7 vs. 2.8 (P < 0.0001). Full-term deliveries: 3.6 vs. 13.4% (P < 0.05). Better oocyte retrieval was achieved (5.3 vs. 3.3; P = 0.001) in the group that was 40 years or over, but there were no differences in the rate of embryo transfer (1.9 vs. 1.3; NS) and full-term deliveries (4.2 vs. 2.9%) in a long protocol compared to a short one. The results of the study are similar to those found in the literature. Indications for standard IVF without oocyte donation should be carefully thought out and couples should be warned of the low success rate.

Adult↗
PubMed1997

[Medical treatment exclusively for cervical pregnancy with in situ methotrexate].

We present a case report of cervical pregnancy with medical treatment. Medical treatment consisted in injection of methotrexate (50 mg) into the pregnancy, on the first, third and seventh day. Ultrasound and Doppler give important information for follow up. The pregnancy totally resolved and the patient did not need any further treatment.

Adult↗
PubMed1994

Th2 cytokine mRNA expression in skin in cutaneous T-cell lymphoma.

We have previously demonstrated that peripheral blood mononuclear cells from patients with Sézary syndrome, the leukemic form of cutaneous T-cell lymphoma which is accompanied by erythroderma and lymphadenopathy, have a Th2 cell cytokine [interleukin 4 (IL-4) and interleukin 5] production pattern. In this study, we extend these observations to demonstrate a correlation of the presence of a Th2 cytokine pattern with a malignant T-cell clone in different stages of cutaneous involvement among patients with cutaneous T-cell lymphoma (CTCL). Skin biopsies were obtained from 12 CTCL patients with various disease stages (three patch, three plaque, six tumor), three patients with parapsoriasis, four patients with inflammatory dermatoses, including two psoriasis and two lichen planus, and 12 normal controls. Total RNA was extracted, reverse transcribed, and PCR amplified with IL-2, IL-4, IL-5, interferon gamma (IFN-gamma), and beta-actin oligonucleotide primers. Although all skin specimens tested had detectable IL-2 and IFN-gamma mRNA, only specimens from patients with CTCL or parapsoriasis had demonstrable IL-4 and/or IL-5 mRNA. Specifically, IL-5 mRNA was detected in skin biopsies from five of six tumor-stage CTCL, two of three plaque-stage CTCL, one of three patch-stage CTCL, and 1 of 3 parapsoriasis patients, whereas IL-4 mRNA was demonstrated to be present in five of six tumor-stage, one of three plaque stage, none of three patch-stage CTCL, and none of three parapsoriasis patients. These results indicate that in all stages of cutaneous involvement of CTCL, encompassing patch stage through tumor stage, IL-4 and IL-5 mRNA is variably detectable. In tumor-stage skin lesions, typically characterized by a dense dermal infiltrate of malignant T cells, Th2 cytokine mRNA is virtually always detectable. The ability to detect Th2 cytokine mRNA in the skin of patients with CTCL supports our previous findings that the malignant T cells in CTCL possess a Th2-helper cell phenotype.

Base Sequence↗
PubMed1994

[Human articular chondrocyte culture. Value in pharmacotoxicology].

Inflammatory and degenerative joint diseases are a major health problem of today. Research is aimed at understanding the processes that bring about degeneration and at the pharmacotoxicological studies of new compounds. Articular cartilage is a connective tissue consisting of an organized extracellular matrix, composed of collagen and proteoglycan aggregates, in which chondrocytes are embedded. Chondrocyte culture has been developed since 1971. However, the use of human chondrocytes for pharmacotoxicology studies is much more recent. The effect of agents can be studied on a number of aspects of chondrocyte metabolism. The most studied are: cell proliferation, proteoglycan degradation and release of matrix proteolytic enzymes or cytokines in the culture medium. Several types of chondrocyte culture can be used for in vitro studies. Organ culture of cartilage slices permits investigation on intact tissue. Chondrocytes can also be released from the articular tissue by serial enzymatic digestions and cultured in a monolayer or tridimensional system. Monolayer culture is easy to set up and allows the culture of large amounts of cells. However, this type of culture is hindered by the phenotypic instability of the chondrocytes. Culture in suspension or within a gel (agarose, collagen) or alginate beads is more suitable for the maintenance of the differentiated phenotype. Chondrocyte immortalization by transfection with oncogenes has been described, but the immortalizing agent still needs to be improved to permit the maintenance of some differentiative properties. The most studied agents are non-steroidal anti-inflammatory drugs. Chondroprotective drugs should also be mentioned. The type of chondrocyte culture for pharmacotoxicological study should be chosen keeping in mind the expected goals of the research undertaken.

Cartilage, Articular↗
PubMed1993

Development of immortalized human articular cartilage cell lines.

Human articular cartilage cells were transfected with the t.-sensitive polyomavirus large T antigen of SV40. Several immortalized chondrocyte cell lines were obtained. The types of acidic polysaccharides and of collagen synthesized suggest dedifferentiation in the in vitro culture system used afterwards to obtain large numbers of cells.

Antigens, Polyomavirus Transforming↗
PubMed1993

Feasibility study of intraarterial vs intravenous cisplatin, BCNU, and teniposide combined with systemic cisplatin, teniposide, cytosine arabinoside, glycerol and mannitol in the treatment of primary and metastatic brain tumors.

Sixteen patients with intracerebral tumors received intraarterial cisplatin, teniposide, and BCNU combined with intravenous cisplatin, teniposide, and cytosine arabinoside. Oral glycerol and intravenous mannitol were given along with the intravenous chemotherapy in an attempt to increase drug delivery to tumor by augmenting tumor blood flow. Thirteen additional patients were treated with the same regimen, but received all the chemotherapy intravenously. Of the 16 patients receiving intraarterial chemotherapy (median survival, 14 weeks), none responded, 5 (31%) were stable for > 8 weeks, 8 (50%) failed, and 3 (19%) were unevaluable due to early death. Of the 13 patients receiving all their treatment intravenously (median survival, 13 weeks), 3 (23%) responded, 1 (8%) was stable, 7 (54%) failed, and 2 (15%) were unevaluable due to early death. In the patients receiving intraarterial chemotherapy, toxicity included ipsilateral retinal toxicity (2 patients), ocular pain or headache (10), periorbital swelling and flushing (6), increased brain edema with focal neurological deficits and drowsiness (5), and catheter-related carotid artery thrombosis followed by fatal herniation (1). Myelosuppression was worse in patients who received all their treatment intravenously than in those receiving intraarterial chemotherapy (p < 0.05). Neutropenic sepsis developed in 4 patients on the intraarterial arm (1 fatal) and in 5 patients on the intravenous arm (2 fatal). Other toxic effects were similar whether or not patients received intraarterial treatment or only intravenous treatment. Overall, toxicity of this regimen was excessive, and response rates were lower than would have been expected with single agent therapy.

Adult↗
PubMed1992

Caudate nucleus pathology in Parkinson's disease: ultrastructural and biochemical findings in biopsy material.

Ultrastructural and biochemical properties of caudate nucleus (CN) biopsies in two patients with advanced Parkinson's disease (PD) were compared with three CN specimens removed during surgery for intracranial tumors. An additional two specimens from neurologically intact patients (59 and 86 years old) were removed during autopsy (performed 3 and 4 h post mortem, respectively) for electron microscopic studies. Dopamine levels in PD were reduced to less than 15% of control values. Both PD patients showed frequent dystrophic neurites and transsynaptic degeneration of neurons and neuritic processes. These changes were not found in CN from the four control individuals. Only a few dystrophic neurites were noticed in one 67-year-old control patient. The development of neuroaxonal dystrophy in CN is consistent with a dying-back process, probably accompanying abnormalities of axonal transport in PD. Transsynaptic degeneration of neurons in CN very likely represents a morphological marker of disease severity. The occurrence of this change may account for the poor clinical response of patients with advanced PD to intracerebral implantation of dopaminergic tissues.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1992

Differential temperature sensitivity of cultured cells from cartilaginous or bone origin.

The effects of long-term exposure to hyperthermia were studied on several cell cultures of cartilaginous or bone origin after a 4-day treatment at 40 degrees C. Chondrocytes proliferation, as well as mitochondrial activity were not modified by these culture conditions (40 degrees C) but protein content and cell volume were increased. In contrast, the proliferative capacity of osteoblasts, MC3T3.E1 a and ROS 17/2.8 was decreased and their protein content, cell volume and mitochondrial activity were increased. Chondrocytes appeared to be thermoresistant, and osteoblastic cells thermosensitive. Furthermore, temperature sensitivity was greater for the continuous established osteoblastic cell line MC3T3.E1 and for the cancerous established osteoblastic cell line ROS 17/2.8 than for chondrocytes.

Animals↗
PubMed1990

Atypical subependymoma of the spinal cord: ultrastructural and immunohistochemical studies.

A 76-year-old woman with a 2-year history of progressive weakness of the left arm and leg underwent a laminectomy for an intradural, extramedullary, pedunculated subependymoma involving the meninges and spinal nerve roots at C7-T1. Eight months later, another operation was necessary for an intramedullary neoplasm at C3-T4. This latter tumor consisted of small, poorly developed cells, large atypical astrocytes, and ependymal cells. Neither ependymal rosettes nor papillary formations were present. Ultrastructural studies showed some features of ependymal differentiation of the large "astrocytic" cells. This case illustrates an unusual pattern of extramedullary and intramedullary presentations of subependymoma and a spectrum of cellular differentiation of neoplastic subependymal glia.

Aged↗