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Biomedical subjects

S Fremont

Publications and source records attributed to S Fremont.

At least 19 recordsLinked to original sources
PubMed2004

[Delayed diagnosis of homocystinuria by major deficiency in cystathionine beta synthase].

INTRODUCTION: Homocystinuria due to cystathionine beta synthase (CBS) deficiency is a special type of hyperhomocysteinemia because of its clinical expression (thrombotic events, ectopic lens and mental retardation). It's a rare, hereditary recessive autosomic disease generally diagnosed during childhood. EXEGESIS: Thrombophilia examination in a 50-year-old man found a dramatically increase homocysteinemia. Homocystinuria, profile of plasmatic amino acids and reduced CBS activity, (0.05 microkat/kg protein; N = 1.5 +/- 0.8) confirmed homocystinuria's diagnosis. Family study demonstrates that three siblings suffer from homocystinuria. Vitamin enriched diet with pyridoxin, vitamin B12 and folates induced reducing hyperhomocysteinemia and homocystinuria. CONCLUSION: This case report, original because of the diagnosis age, suggests a hyperhomocysteinemia's screening in patients with recurrent thrombotic events.

Cystathionine beta-Synthase↗
PubMed2002

Allergenicity of some isoforms of white sesame proteins.

BACKGROUND: Allergy to sesame seeds is often associated with particularly severe reactions, with a high risk of anaphylaxis. The increase in reports of allergic reactions to sesame is probably due to the growing use of sesame seeds or sesame oil in food. OBJECTIVE: To determine the molecular weights of the proteins in three variety of sesame seeds and to study the isoelectric points and the allergenicity of white sesame proteins. METHODS: Extracts of white, brown and black sesame seeds were prepared. The white sesame extract, mostly used in bakery, was run on SDS-PAGE and two dimensional electrophoresis. Six sera from patients sensitized or symptomatic to sesame seed were used for Western blotting. RESULTS: The protein patterns of the white, brown and black sesame extracts showed major quantitative differences. The white extract had the higher protein concentration and contained 15 proteins of 12-79 kDa, some of them having several acidic isoelectric points. The lowest isoelectric point was 4.9 and the highest was 6.4, giving 35 isoforms. Ten of the 15 proteins (12-57.5 kDa) were recognized by specific IgE. The 12-13 kDa and 22-33 kDa proteins could correspond to the main allergens. CONCLUSION: White sesame seeds contain at least 10 allergenic proteins with acidic isoelectric points. In accordance with previous results, two of them seem to contain the major allergens.

Adolescent↗
PubMed2001

Latex hypersensitivity in spinal cord injured adult patients.

Latex hypersensitivity is a major cause of anaphylaxis during anaesthesia. Patients with spina bifida, health care or rubber industry workers have been considered at risk for latex sensitization. By analogy, the existence of other at-risk subsets of patients with latex exposure due to frequent surgical procedures has been suggested. The aim of this study was to evaluate the prevalence of latex sensitization in a cohort of adult patients with spinal cord injury and repeated latex exposure. Forty-two adult patients with spinal cord injury were studied and retrospectively compared to a group of 30 children with spina bifida evaluated using a similar protocol. Patients were administered a questionnaire concerning history of latex hypersensitivity, atopy, and surgical procedures. Latex sensitivity was investigated by skin prick-tests and latex-specific IgE assay. The search for atopy was based on in vivo and in vitro tests against a panel of environmental allergens. No chronic spinal cord injured patient had a history of latex allergy. When compared with spina bifida, the number of surgical procedures was not statistically different. Although not significantly different, the prevalence of atopy was higher in spina bifida patients. The high level of latex sensitization in spina bifida patients contrasted sharply with the absence of sensitization observed on both skin and in vitro tests in patients with spinal cord injury (P<0.0001). This study confirms that adult patients with chronic neurologic defects resulting from spinal cord injury exhibit a low risk of latex sensitization. These results suggest that considering adult patients with repeated surgical procedures as a group at risk for latex sensitization because of a high degree of latex exposure should be re-examined.

Adolescent↗
PubMed2000

Influence of refining steps on trace allergenic protein content in sunflower oil.

BACKGROUND: Although allergy to sunflower seed and oil is a relatively rare occurrence, several cases of sunflower seed allergy have been observed, and we have already described one case of anaphylaxis after eating sunflower oil and margarine. OBJECTIVE: The aim of our study was to determine and characterize the allergens from sunflower oil at the different steps of the refining process: crude pressed oil (step A), acidification and neutralization (step B), pregumming by centrifugation (step C), washing (step D), bleaching (step E), gumming by filtration (step F), and deodorization (step G). METHODS: A sample of oil from each step of the process (steps A to G) was heat extracted with PBS. The protein concentration of each extract was evaluated by using the micro-Bradford assay. Samples were run on SDS-PAGE. The immunoblot was performed with the serum of a patient sensitized to sunflower seed and oil. RESULTS: The extracts obtained after each step reveal a decrease in total protein concentration from 13.6 microg/mL to 0. 22 microg/mL. The result of SDS-PAGE shows 5 bands, from 67 kd to 145 kd, with the most abundant being the 67-kd protein. The amount of this protein decreases after each step of the process. It is, however, still present in trace amounts in the refined oil. The 67-kd protein, which is mainly present in the crude oil and slightly in the refined oil, has been shown to be allergenic. CONCLUSION: Because of the presence of allergenic proteins, refined sunflower oil may pose a threat to people highly sensitized to sunflower seeds.

2S Albumins, Plant↗
PubMed1999

Human haptocorrin in hepatocellular carcinoma.

This study aimed to determine whether haptocorrin (HC), a vitamin B12 binder, is stored in hepatic cells and whether this storage is modified by hepatic carcinogenesis. It was carried out using immunohistochemistry on different liver tissues (normal liver and steatosis, N = 22; cirrhosis, N = 13; and hepatocellular carcinoma, N = 31). No significant immunostaining of HC was detected in noncancerous biopsies with the exception of in one case of cirrhosis. Hepatocellular carcinoma (HCC) sections showed a weak to moderate cytoplasmic staining of cancerous cells (93% of cases) and of noncancerous hepatocytes surrounding the tumor (95%) of cases. Sections with pseudoglandular structures showed a moderate to strong staining of their secretion products. These results and previous studies would seem to confirm the hypothesis that the raised HC serum level observed in HCC is due both to the increased hepatic synthesis of HC and to a decreased uptake by the liver of the particular isoform of this glycoprotein present in the serum of HCC patients.

Biomarkers↗
PubMed1997

Combination of high-performance liquid chromatography and thin-layer chromatography separation of five adducted nucleotides isolated from liver resulting from intraperitoneal administration with 7H-dibenzo[c,g]carbazole to mice.

7H-Dibenzo[c,g]carbazole, DBC, is a potent environmental liver carcinogen. Liver DNA from mice treated with DBC exhibited seven distinct DBC-DNA adducts as detected by 32P-postlabeling using multidimensional TLC. To improve quantitation and chemically characterize the adducts, DNA samples were hydrolyzed, 32P-postlabeled and the adducts were separated from the unadducted normal nucleotides on TLC using a D1 solvent, 0.65 M sodium phosphate (pH 6.8). Adducts were eluted from the TLC plates with 4.0 M pyridinium formate, concentrated, resuspended in 50% aqueous methanol and injected onto the HPLC; five individual adduct peaks were resolved and collected by this method. This approach will prove useful to decrease analysis time and improve chemical characterization of tightly clustered DNA adducts generated in vivo.

Animals↗
PubMed1997

Transfer of atopy following bone marrow transplantation.

BACKGROUND: Bone marrow transplantation is an optimal treatment of acute leukemia and aplastic anemia. Allergic manifestations in recipients long after bone marrow transplantation have been reported. A case involving transfer of atopy manifested as food allergy-induced-atopic dermatitis is reported. METHODS: The donor and the patient were investigated by prick tests and RAST to the same food allergens. Single blind, oral challenge to egg documented food allergy in the recipient. RESULTS: A 5-year-old boy without history of atopy developed severe atopic dermatitis after bone marrow transplantation from his HLA-identical sister for acute lymphoblastic leukemia. The patient's course had been marked previously by acute graft versus host disease and cytomegalovirus infection. Immunoallergic evaluation showed an exquisite sensitization to egg, peanut, and soybean. Total IgE was 6400 KIU/L. Concomitantly, the donor showed the same sensitizations. Absolute avoidance resulted in the regression of atopic dermatitis. Subsequently, new sensitization to wheat flour, Dermatophagoides pteronyssinus, birch, and plantain pollens was detected. The donor developed asthma. CONCLUSIONS: This case gives evidence of the transfer of sensitization from donor to recipient. The passive transfer of memory cells within the bone marrow inoculum is a possible mechanism. The current concept of allergy supports down regulation of Th1 cells to the benefit of Th2 cells. Additional deregulation induced by acute graft versus host disease, cytomegalovirus infection, and immunosuppression is possible.

Bone Marrow Transplantation↗
PubMed1997

Low-density lipoprotein ability to generate lipoperoxides in healthy subjects: variations according to age.

Oxidized low-density lipoproteins (LDLs) are recognized to be involved in atherosclerosis development. Since the plasma oxidized LDL assay is inadequate because of the short half-lives of LDLs, measurement of the in vitro ability of LDLs to generate lipoperoxides (LDL-GLs) has been preferred. The present study displays a profile of LDL-GLs in a group of 175 healthy subjects, using a method to measure thiobarbituric acid-reactive substances. We have observed an increased LDL-GL level according to age.

Adolescent↗
PubMed1995

Food anaphylaxis following ingestion of carmine.

BACKGROUND: The risk of sensitization to reactive dyes is well established. The clinical situation is caused most often by synthetic azo dyes and triphenylmethane derivatives but natural dyes such as carmine extracted from dried female insects, Coccus cacti (cochineal), have been incriminated. OBJECTIVE: Study of a case of anaphylaxis after ingestion of yogurt to establish the responsibility of carmine. METHOD: Case report of a patient who received skin prick test and leukocyte histamine release test with carmine and yogurt. CONCLUSIONS: This case provided evidence of an IgE-dependent mechanism and draws attention to the triggering dose of carmine (1 mg) although the acceptable daily intake is up to 5.0 mg per kg of body weight.

Adult↗
PubMed1995

Anaphylaxis to mustard as a masked allergen in "chicken dips".

BACKGROUND: Masked allergens in processed foods are sometimes responsible for "idiopathic" anaphylaxis because of the lack of full ingredient labeling. Patients, even if they are aware of a specific hypersensitivity, may be unaware of trace amounts of the offending allergen(s) that are present in these products. METHODS: We report a case of severe anaphylaxis to mustard masked in "chicken dips." A 38-year-old woman had an anaphylactic reaction beginning 20 minutes after eating "chicken dips" in a fast food restaurant. She was treated successfully in an emergency room and then referred to us for evaluation. We performed skin prick tests, IgE antibody, and inhibition assays to identify allergens in foods eaten just prior to the anaphylactic reaction. RESULTS: She had a history of allergy to mustard. Skin prick tests revealed sensitivity to mustard, coriander, and curry powder, which contains mustard. She had 56.3 KU/L mustard-specific serum IgE antibody in a Phadebas CAP RAST assay (Pharmacia, Sweden). The mustard RAST was inhibited with an extract of "chicken dips," confirming the presence of mustard in "chicken dips." CONCLUSIONS: This case points out the risk of masked allergens in modern food products and the value of the RAST inhibition assay for the identification of such hidden allergens.

Adult↗
PubMed1992

The plasma membrane of epididymal epithelial cells has a specific receptor which binds to androgen-binding protein and sex steroid-binding protein.

The binding of [3H] delta 6-testosterone photoaffinity-labelled rat androgen-binding protein (rABP) has been studied in an enriched fraction of plasma membranes of epithelial epididymal cells in immature (15 days) and adult rats (40 days). The binding was maximal in less than 30 min and more rapid at 4 degrees C than at 34 degrees C. It was calcium and pH dependent. Scatchard plots of the binding data gave curvilinear plots with two types of binding sites corresponding to a K(ass1) of 18.2 nM-1 and K(ass2) of 1.6 nM-1 (2.2 x 10(11) sites/mg protein and 5.4 x 10(11) sites/mg protein, respectively). In adult rats, only one type of binding site was found, with a K(ass) of 3.7 nM-1 (4.5 x 10(11) sites/mg protein). The number of receptors was 5-fold lower in the cauda than in the caput of the epididymis. The pretreatment of the isolated intact cells with streptozotocin induced a 45% reduction of the binding. Only unlabelled rABP and hSBP (human sex steroid-binding protein) but not other proteins (lactotransferrin, serotransferrin, asialofetuine, fetuine and bovine serum albumin) competed with the labelled ligand to bind plasma membranes. The membrane fraction was solubilized by triton X-100. Its incubation with labelled rABP and hSBP provoked the elution of the tracer as an aggregate into the void volume fraction of superose 6B mini-gel filtration columns. Structural homology between hSBP and rABP could be responsible for the common behaviour of the steroid-carrier molecules for the ABP receptor of rat epididymal epithelial cells.

Age Factors↗
PubMed1991

Evidence that androgen-binding protein endocytosis in vitro is receptor mediated in principal cells of the rat epididymis.

We have studied the binding of [125I-iodo]androgen-binding protein (ABP) and of [3H]delta 6-testosterone photoaffinity-labelled ABP to receptors in the plasma membrane of rat epididymal cells in three ways: ABP binding to a Triton X-100-solubilized membrane extract, ABP binding to isolated epithelial cells in suspension and autoradiography of segments of dissected epididymides after in-vitro intraluminal injection of labelled ABP. The binding of iodinated ABP to the receptor was similar to that of photoaffinity-labelled ABP in gel filtration. The ABP-receptor complex was eluted from Superose 6 gels as an aggregate, with a molecular mass of 2000 kDa. It was separated into two peaks by sucrose gradient ultracentrifugation, with respective sedimentation coefficients of 18.4 and 9.0 s. The activity of the receptor (ABP-binding capacity/mg protein) was tenfold higher in the caput than in the cauda. The binding of ABP to the receptor was pH dependent, being almost abolished at pH less than 4. The binding at 4 degrees C of photoaffinity-labelled ABP to epithelial cells corresponded to two types of binding sites. The numbers of high-affinity and low-affinity sites per cell were 1600 and 7700 respectively; the association constants of these sites were 67.9 and 2.8 litres/nM respectively. The binding was decreased by treatment of the cells with trypsin or incubation in the presence of EDTA. The binding in vitro of labelled ABP to the epididymis epithelium reached a maximum after about 20 min at 4 degrees C. In the autoradiographic study the tracer was found to be closely associated with coated pits, coated vesicles, endosomes and pale multivesicular bodies. Treatment of rats with cycloheximide significantly reduced the uptake of the tracer. Perfusion in vitro of epididymides with chloroquine produced a fourfold increase of the tracer in endosomes and multivesicular bodies.

Androgen-Binding Protein↗