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Biomedical subjects

J M Garnier

Publications and source records attributed to J M Garnier.

At least 109 records · Page 6Linked to original sources

Evolution of the HLA-DR1 gene family. Structural and functional analysis of the new allele "DR-BON".

The molecules of the MHC are highly polymorphic and involve in Ag presentation; their striking genetic polymorphism allows probable interactions with a large variety of antigenic fragments when these are presented to the TCR. It is therefore of interest to explore the extent of this polymorphism and the mechanisms of its generation. We have studied the class II HLA-DR blank allele DR-BON that has been previously defined by MLR, restriction fragment length polymorphism, and two-dimensional gel electrophoresis. A cDNA library was constructed from a DR-BON homozygous typing cell and cDNA corresponding to DR alpha- and DR beta-chains were sequenced. By comparison with other known alpha- and beta-chain sequences it is shown that the alpha-chain is invariant and the beta-chain differs from DR1 by only six nucleotides, clustered in the third variable region with three amino acid changes at position 67, 70, and 71. The short DNA stretch of sequence encoding the 67-71 region is also present in other DR alleles: DR4/Dw10, DRw13, and some DRw11 specificities. Therefore we propose that a gene conversion-like event has occurred between the DRB1 *0101 (DR1/Dw1) gene and one of these three DRB1 genes. Extensive typing has been performed with a DR-BON-specific 17-mer oligonucleotide. Cross-hybridization with other genes than the ones expected from DNA sequence comparison was not observed. A selected panel of DR-BON reactive T cell clones shows three patterns of reactivity. Some clones are strictly DR-BON specific; some cross-reacted with DRw13 and a few cross-reacted with other haplotypes. The role of different epitopes of the third variable region of HLA-DR beta chain in allo-reaction is discussed.

Alleles↗

Murine isoforms of retinoic acid receptor gamma with specific patterns of expression.

We have characterized seven murine retinoic acid receptor gamma cDNA isoforms (mRAR-gamma 1 to -gamma 7) generated by alternative splicing of at least seven exons. These isoforms differ from one another in their 5' untranslated region and in two cases (mRAR-gamma 1 and -gamma 2) differ in their N-terminal A region, which is known to be important for differential transactivation by other nuclear receptors. mRAR-gamma 1 and -gamma 2, the predominant isoforms, are differentially expressed in adult tissues and during embryogenesis. Most notably, skin contains almost exclusively mRAR-gamma 1 transcripts. The conservation of the RAR-gamma isoforms from mouse to human together with their patterns of expression suggests that they perform specific functions, which may account for the pleiotropic effect of retinoic acid in embryogenesis and development.

Animals↗

[Septicemia, portal thrombosis and congenital protein C deficiency].

The authors report a case of Bacteroides fragilis septicemia with left portal vein thrombosis secondary to a liver abscess discovered by ultrasonography. This thrombosis was in relation with hereditary protein C deficiency. The authors emphasize the importance of assaying for C protein along with the other physiological coagulation inhibitors in the child presenting with venous thrombosis.

Bacteroides Infections↗

The chicken progesterone receptor: sequence, expression and functional analysis.

The complete mRNA sequence of the chicken progesterone receptor (cPR) has been determined. Expression of the cloned cDNA both in vivo and in vitro produces a protein that has the same apparent mol. wt on SDS--polyacrylamide gels as the 'natural' cPR form B (109 kd) as determined by immunoblotting and photoaffinity labelling. When expressed in HeLa or in Cos-1 cells the 'cloned' cPR displays hormone binding characteristics indistinguishable from the 'natural' receptor and, in the presence of progestins, exhibits 'tight nuclear binding'. A protein corresponding in size to the cPR form A (79 kd) could be detected by expressing in vivo and in vitro an N-terminally truncated cPR starting at methionine 128. A protein of the same apparent mol. wt results from internal initiation during in vitro translation. In contrast, such a protein was barely detectable after in vivo expression of the cPR cDNA in Cos-1 cells. These results suggest that form A is generated by an oviduct cell specific process involving either internal initiation of translation and/or proteolysis in the vicinity of methionine-128. The cPR contains two highly conserved regions C and E, a characteristic of the steroid/thyroid hormone receptor supergene family. By expression of a series of cPR deletion mutants, region E could be defined as the hormone binding domain whereas region C is indispensable for the tight nuclear association of the progestin-receptor complex. In the presence of progestins, the cloned cPR efficiently trans-activates transcription from the long terminal repeat region (LTR) of the mouse mammary tumor virus (MMTV). Deletion of the entire N-terminal region A/B or of the hormone binding domain E results in a 100-fold reduction of transcriptional activation. No stimulation of transcription can be detected when the C-terminal deletion extends into region C, indicating that this region is involved in the recognition of the hormone responsive element (HRE) of the MMTV LTR.

Amino Acid Sequence↗

Structure of the human oestrogen-responsive gene pS2.

The human pS2 gene, whose expression is restricted to breast cancer cells, and whose transcription is induced by oestrogen in the human breast cancer cell line MCF-7, has been cloned from both placental and MCF-7 cell DNA. The exon-intron organization has been established by electron microscopy using genomic DNA-cDNA or -mRNA hybrid duplexes and by sequencing the exons and exon-intron junctions. The overall organization within and around the pS2 gene is the same in placental and MCF-7 cell DNA and the exonic sequences are identical to those previously determined from the cDNA. The 5'-flanking region of the pS2 gene is also identical (with the exception of two base transitions) in the two tissues. Thus no gene rearrangement nor sequence modification has occurred in the pS2 gene of the malignant and polyploid MCF-7 cells. A TATA-box, a CAAT-box and a GC-rich motif are present in the 5'-flanking region of the pS2 gene, but the latter motif is unusually located between the TATA-box and the capsite. No significant homology could be detected between the 5' flanking sequences of the pS2 gene and those of other oestrogen-responsive genes from different species.

Amino Acid Sequence↗

Cloning of the saliva-interacting protein gene from Streptococcus mutans.

Genomic libraries from Streptococcus mutans OMZ175 were constructed in bacteriophage vectors. DNA fragments 1 to 2 kilobases in length were cloned in expression vector lambda gt11. S. mutans DNA fragments 15 to 20 kilobases in length were inserted in the BamHI site of phage EMBL3. Rabbit antiserum raised against an S. mutans saliva-interacting protein with a molecular weight of 74,000, designated 74K SR, was used to screen the lambda gt11 library. A recombinant phage carrying an S. mutans DNA sequence of 1.45 kilobases, lambda SmAD2, was detected and isolated. This fragment, named SmAD2, was used to construct the recombinant expression plasmid pSAD2-4 which encoded for the expression of a 60,000-molecular-weight protein controlled by the beta-galactosidase promoter from plasmid pUC8. The SmAD2 fragment and polyclonal anti-74K SR antibodies were used to screen the EMBL3 library. A total coincidence between the screening with antibodies and the DNA probe was observed, and two phages, lambda SmAD9 and lambda SmAD10, were isolated. They contained a common S. mutans DNA sequence of about 11.8 kilobases and coded for a protein with a molecular weight of about 195,000, which comigrated with a protein of an S. mutans cell wall extract. The expressed protein was purified, and a very strong relationship with the S. mutans 74K SR protein was found by competitive enzyme-linked immunosorbent assay. Thus, cloning of the 74K SR gene allowed us to demonstrate that the saliva receptor appears to be a part of an S. mutans precursor molecule with a molecular mass of 195,000 daltons.

Bacterial Proteins↗

Cloning of the chicken progesterone receptor.

Monospecific antibodies directed against the chicken progesterone receptor (PR) form B were used to screen a randomly primed phage lambda gt11 cDNA expression library prepared from size-fractionated chicken oviduct mRNA. Two independent immunoreactive clones, lambda cPR1 and lambda cPR2, were isolated. Antibodies selected from anti-PR form B antiserum on matrices of lambda cPR1 and lambda cPR2 fusion proteins detected two proteins on electrophoretic immunoblots of crude and purified PR preparations. These proteins had the same apparent molecular weights as did PR forms A and B crosslinked with the tritiated progestin R 5020. Thus, lambda cPR1 and lambda cPR2 fusion proteins contain epitopes present in both PR forms A and B. A cDNA clone, lambda cPR3, containing the inserts of both lambda cPR1 and lambda cPR2, was isolated from a randomly primed lambda gt10 oviduct cDNA library, indicating that both cDNA inserts were derived from the same oviduct mRNA. Additional evidence that these cDNAs correspond to PR mRNA was provided by sequencing the lambda cPR3 cDNA insert, since it was found to encode the sequence of three tryptic peptides prepared from purified PR form B. A fourth and a fifth cDNA clone, lambda cPR4 and lambda cPR5, were sequentially isolated from the same lambda gt10 cDNA library beginning with a probe derived from the 3' end of the lambda cPR3 insert. Partial DNA sequencing of lambda cPR4 and lambda cPR5 revealed the presence of a sequence coding for a cysteine-rich domain that is strikingly homologous to the amino acid sequences present in the putative DNA-binding domain of the human and chicken estrogen receptors, human glucocorticoid receptor, and v-erbA gene product of the avian erythroblastosis virus.

Amino Acid Sequence↗

Scedosporium (Monosporium) apiospermum: multiple brain abscesses.

A 32-year-old female with alcoholic cirrhosis attempted to drown herself in a pond. She remained in a coma for 57 days. After a stormy course she developed multiple brain abscesses due to Scedosporium (Monosporium) apiospermum. Despite intravenous and intrathecal amphotericin B (total dose 870 mg) the patient died 71 days after the near drowning.

Adult↗

[Juvenile chronic arthritis. Double-blind study of the efficacy and tolerance of D-penicillamine].

Seventy-four children with juvenile chronic arthritis were admitted to a 6-month multicentric double blind comparative study of the efficiency of D-Penicillamine or placebo. The results evaluated in 55 patients who completed the study, indicated an improvement in the total number of stiff joints and in the total index of severity measuring joint pain and inflammation. A significant reduction of the concurrent use of non steroidal antiinflammatory drugs was also observed. The tolerance was good except in two patients. Some children in the placebo group exhibited a definite improvement.

Arthritis, Juvenile↗

[Mediterranean boutonneuse fever. Apropos of 154 recent cases].

The Mediterranean spotted fever is always present in the south of France. The actual incidence is unknown. The disease appears in summer. The diagnostic is based on the association of fever, "black spot" and exanthema and/or a seroconversion. Indirect immunofluorescence is the most used technique. Some patients have severe complications: neurologic, cardiovascular, renal, thrombopenia. These cases look like Rocky Mountain Spotted Fever. The treatment is based on tetracycline.

Adolescent↗