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Biomedical subjects

A Samuelsson

Publications and source records attributed to A Samuelsson.

46 records · Page 3Linked to original sources
PubMed1993

Identification of four antibody-binding sites in the envelope proteins of simian immunodeficiency virus, SIVsm.

OBJECTIVE: To identify antigenic regions in the envelope glycoproteins of the simian immunodeficiency virus isolate, SIVsm. METHODS: Thirty-eight peptides were synthesized and used in site-directed enzyme-linked immunosorbent assays with sera from experimentally infected macaques. RESULTS: Four antibody-binding regions were identified, corresponding to the second variable region [V2; amino acids (aa) 170-196], the region homologous to V3 in HIV-1 (aa 313-346), the carboxy terminus of gp120 (aa 514-537) and the amino terminus of the transmembrane protein (aa 608-638). Serum reactivity to the V2 region was higher in surviving monkeys than in animals with an early development of simian AIDS. The antigenicity of the peptide appears to be conformationally dependent. CONCLUSIONS: The majority of antigenic sites identified in the envelope proteins of SIV correspond to sites identified in HIV-1 and HIV-2, which further supports the use of the simian model in vaccine development. The pattern of reactivity to the V2 region suggests that absence of antibodies directed to this site might correlate with disease progression.

Amino Acid Sequence↗
PubMed1993

Two highly antigenic sites in the human immunodeficiency virus type 1 reverse transcriptase.

Antibodies to human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) are found in the serum of the majority of infected individuals, and inhibition of RT polymerase activity by HIV-1-positive sera can be demonstrated in vitro. The binding sites of human antibodies on the protein have not yet been identified. We synthesized overlapping peptides covering the entire RT protein of HIV-1 and used them in an enzyme-linked immunosorbent assay system to map the reactivities of HIV-1 and HIV-2 antibody-positive sera. Two highly antigenic regions were identified by both HIV serotypes. One region was found in the central part of the RT protein (amino acids 261 to 280) and another was found at the carboxy terminus in the RNase H portion of RT (amino acids 517 to 536). Comparison of the serological results with the crystal structure of the RT revealed that the antigenic region in the RNase H portion is located at the surface of the protein. The other antibody-binding site (amino acids 261 to 280) was located in the "thumb" region of the polymerase domain of RT. Polyclonal antibodies to either of the antibody-binding sites do not affect the polymerase activity of the RT protein.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Successful pregnancy in a 28-year-old patient autografted for acute lymphoblastic leukemia following myeloablative treatment including total body irradiation.

We report a successful pregnancy in a woman who at the age of 28 years received total body irradiation (TBI; 7.5 Gy) and high-dose chemotherapy prior to autografting of purged bone marrow for acute lymphoblastic leukemia. Four years after transplantation she delivered a healthy girl. Only five previous cases of successful pregnancies are described in the literature after conditioning regimens including TBI. This case shows that restored ovarian function is possible after TBI in spite of prolonged exposure to chemotherapeutic agents during induction and consolidation therapy and relatively high age at the time of transplantation.

Adult↗
PubMed1991

Intrathecal antibody production against viruses of the herpesvirus family in acute retinal necrosis syndrome.

Viruses of the herpesvirus family cause acute retinal necrosis syndrome, a devastating necrotic retinitis in immunocompetent individuals. Direct proof of the viral origin of this disease may be obtained by demonstration of the virus, viral antigens, or viral DNA in biopsy specimens of retinas. In search of alternative diagnostic methods, we analyzed cerebrospinal fluid and serum with enzyme-linked immunosorbent assays for virus-specific antibody activity. Intrathecally produced viral antibodies were found in three consecutive patients with acute retinal necrosis syndrome: herpes simplex type 2 in a 30-year-old woman with a history of suspected neonatal herpes encephalitis, herpes simplex type 1 in a 35-year-old man, and varicella-zoster virus activity in a 62-year-old woman. None of the patients had clinical signs indicating an acute disorder in the central nervous system. This serologic approach seems to be of value for the diagnosis of an associated intracerebral viral infection in cases of acute retinal necrosis syndrome.

Adult↗
PubMedDate not supplied

Gene expression of cyclooxygenase-2, group II and cytosolic phospholipase A2 in human colorectal cancer.

The development of intestinal tumours in the Min mouse is influenced by Moml locus, where the group II phospholipase A2 (PLA2-II) gene has been suggested as the candidate gene. Since no causative genetic alterations have been identified in PLA2-II in human colorectal tumours, we tested whether PLA2-II or the cytosolic isoform cPLA2, are dysregulated in human colorectal carcinogenesis. By means of RT-PCR, the expression of these genes and cyclooxygenase-2 (COX-2), which is upregulated in colorectal tumours, were examined. No changes in gene expression of PLA2-II were found in 44 tumours compared to normal mucosa. cPLA2 and COX-2 were upregulated; however, no correlation in expression was found between these genes. Thus, the supply of arachidonic acid provided by PLA2-II/cPLA2 seems not to be the rate limiting step in PGE2 (a prostaglandin/mitogen) formation via COX-2 and PLA2-II plays a minor or no role in human colorectal carcinogenesis.

Adult↗