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Biomedical subjects

A Larsson

Publications and source records attributed to A Larsson.

At least 541 records · Page 30Linked to original sources
PubMed1975

In vitro target cell lysis mediated by normal human lymphocytes (K cells) or monocytes.

Guinea pig IgG1 or IgG2 anti-dinitrophenyl (DNP) Antibody preparations were used for induction of target cell lysis by normal human lymphocytes (K cells) or monocytes. Target cells were DNP-coated 51Cr-labeled chicken erythrocytes. Antibody concentrations were assayed by an ammonium sulphate precipitation technique. When antiserum was obtained by immunization with the antigen in Freund's complete adjuvant (FCA), IgG2 antibodies predominated and were significantly more efficient inducers of K-cell-mediated lysis than IgG1 antibodies. The lowest activity in K-cell-mediated lysis was seen with IgG1 from antiserum obtained by immunization with antigen in Freund's incomplete adjuvant. When these antibody fractions were tested in monocyte-mediated erythrolysis, the two IgG1 fractions were as active as the IgG2 antibodies raised with antigen incorporated in FCA. The results suggest that the Fc receptors of mature human blood monocytes are different from those on the effector cells in the K-cell preparations.

Animals↗
PubMed1975

Sequential studies of serum blocking activity in rats bearing chemically induced primary bowel tumors.

Colon and small-bowel tumors were induced in WF rats by treatment with one of three chemical carcinogens. Tumor occurrence and growth were monitored by multiple double-contrast examinations. Roentgenologic diagnoses and histologic examination of tumors were verified at tumor resection or autopsy. Serial serum samples from each of 11 rats were tested in microcytotoxicity assays for their ability to block the cytotoxicity of lymph node cells from rats with isografts of colon carcinoma NG-W1 against NG-W1 target cells. Sera from all tumor-bearing rats demonstrated specific blocking activity. With two exceptions, serum blocking activity preceded roentgenologic evidence of tumor. Sera of the 2 exceptional rats lacked blocking 2 and 8 weeks before tumor detection, respectively. The sera of only one animal specifically inhibited lymphocyte cytotoxicity despite consistently negative double-contrast examinations. At autopsy this rat was found to have an adenocarcinoma of the distal rectum, impossible to visualize by the roentgenologic technique used. In serum samples obtained from animals after successful tumor excision and with no radiologic evidence of recurrence, blocking activity could no longer be demonstrated. Rats that had received carcinogen but developed no tumor and had no abnormalities on double-contrast examination demonstrated no serum blocking activity.

Adenocarcinoma↗
PubMed1974

Glutathione synthetase deficiency, an inborn error of metabolism involving the gamma-glutamyl cycle in patients with 5-oxoprolinuria (pyroglutamic aciduria).

Enzyme studies on placenta, cultured skin fibroblasts, and erythrocytes from two sisters with the inborn error 5-oxoprolinuria (pyroglutamic aciduria) indicate that the metabolic lesion in this disease is at the glutathione synthetase (EC 6.3.2.3) step of the gamma-glutamyl cycle. Excessive urinary excretion of 5-oxoproline by these patients appears to be associated with increased synthesis of gamma-glutamyl-cysteine and formation of 5-oxoproline from this dipeptide. Thus, 5-oxoproline is produced in amounts that exceed the normal capacity of 5-oxoprolinase to convert it to glutamate. The data indicate that it may be possible to identify individuals who are heterozygous for this trait by determinations of erythrocyte glutathione synthetase.

Acyltransferases↗