Biomedical subjects
J Swanson
Publications and source records attributed to J Swanson.
Collagen synthesis by human fibroblasts. Regulation by transforming growth factor-beta in the presence of other inflammatory mediators.
We have examined the combined effects of transforming growth factor-beta (TGF-beta), serum and gamma-interferon (gamma-IFN) on collagen synthesis by fibroblasts and compared the response of fibroblast subpopulations to TGF-beta. Human diploid fibroblasts were treated with TGF-beta alone and with serum of gamma-IFN. Cells were labelled with radioactive amino acids, and collagen production was measured as collagenase-digestible radioactivity. Collagen mRNA was determined by a solution-hybridization assay using procollagen-alpha 1[I] cDNA clone HF 677. The results showed that either serum or TGF-beta increased incorporation, collagen production and mRNA by fibroblasts approx. 2-fold; however, collagen synthesis relative to total protein synthesis and collagen mRNA relative to total polyadenylated [poly(A)+] RNA were not affected. Only serum activated cell growth. Collagen production increased approx. 4-fold in cells exposed to both TGF-beta and serum, and this increase was equal to that expected for an additive effect by both components. Treatment with gamma-IFN decreased collagen production and collagen mRNA to 44 and 40% respectively, whereas total incorporation and poly(A)+ RNA were affected only marginally. Cells exposed simultaneously to both gamma-IFN and TGF-beta produced less collagen and contained less mRNA than did those treated with TGF-beta alone. The gamma-IFN decreased collagen synthesis in control and TGF-beta-treated cultures to a similar extent, and TGF-beta increased collagen synthesis 2-fold in cells pre-treated with gamma-IFN. Fibroblast strains obtained in medium containing plasma-derived serum synthesized approximately half as much collagen as did cells derived from the same explant in the presence of fresh human serum, and TGF-beta stimulated collagen production and mRNA in both cell strains. We conclude that TGF-beta, serum and gamma-IFN regulate collagen synthesis by independent mechanisms, and that the combined action of these components plays a significant role in regulating collagen synthesis during wound healing and tissue repair.
Adverse effects of methylene blue on human sperm motility, components of human reproductive tract fluids, and mouse embryo cleavage.
Because methylene blue exhibits germicidal, oxidation, and reduction properties, the authors asked whether this agent causes adverse effects on gametes, embryos, and/or secretions of the reproductive tract. Time- and dose-dependent inhibition of human sperm motility by methylene blue was observed, as was growth inhibition of 2-cell mouse embryos. Furthermore, the presence of methylene blue in uterine, fallopian tube, and peritoneal fluids altered protein mobility in polyacrylamide gels, and yielded apparent values of follicle-stimulating hormone and estradiol up to 260% of actual values (P less than 0.05). These data suggest that the presence of methylene blue in reproductive tract fluids may provide a false impression of their biochemical and biophysical compositions, and that the use of methylene blue as a chromopertubation agent be conducted with appropriate awareness.
Fluorescent labeling of endocytic compartments.
Explore the source record for details and available documents.
Expression and phase variation of gonococcal P.II genes in Escherichia coli involves ribosomal frameshifting and slipped-strand mispairing.
Expression and phase variation of Neisseria gonorrhoeae P.II genes in Escherichia coli were studied using TnphoA fusions. Fusions were created in the P.IIc gene of N. gonorrhoeae JS3 using lambda TnphoA-1 and were characterized by restriction digestion and dideoxy sequencing. Three fusions were chosen for further study; Tnp7 (fusion junction at mature amino acid 7), Tnp57 (amino acid 57), Tnp66 (amino acid 66). All fusions were in frame with the P.IIc coding sequence but were out of frame with the purported initiation codon. All fusion constructions were shown to phase vary in E. coli in an analogous fashion to that seen in N. gonorrhoeae, i.e. phase changes (in a recA background) at a frequency of c. 10(-3) accompanied by an alteration at the DNA level of the number of coding repeats (CRs). In vitro mutagenesis of the fusion constructions indicated that expression of out of frame P.II genes in E. coli was probably the result of ribosomal frameshifting within the run of 'A' residues immediately preceding the CR region and not due to low-level false initiation at codons other than the ATG initiation codon (as had previously been suggested). The mechanism for P.IIc::phoA phase variation appears to be related to the 'slipped-strand mispairing' mechanism responsible for frameshift mutations in a number of other bacterial genes containing short, direct, tandem repeats.
Expression of outer membrane protein II by gonococci in experimental gonorrhea.
Gonorrheal urethritis was induced in three males by intraurethral instillation of predominantly pilus+ protein II- gonococci. Virtually all gonococci reisolated from the infected men exhibited protein II+ phenotype. The reisolated gonococci expressed five distinct outer membrane protein II species. Protein IIc+ organisms predominated in urines of all three subjects, but variants expressing this particular protein II were rarely spawned in vitro by input organisms. Protein IIc+ gonococci appeared early in one man's infection; they were joined later by variants that displayed eight other protein II phenotypes, including protein II-. These results show that input protein II- gonococci are supplanted by protein IIc+ variants during incipient gonorrheal urethritis. As infection progresses, a broader variety of protein II+ variants appears.
Non-Hodgkin's lymphoma: a case involving four third molar extraction sites.
Explore the source record for details and available documents.
The use of calcium channel blockade for the prevention of postoperative adhesion formation.
Prevention of postoperative adhesion formation is an issue of fundamental concern to the reproductive surgeon. The disappointing results of current adjunctive regimens have prompted a search for more potent antiadhesion therapies. Administration of nifedipine hydrochloride, a prototypical calcium channel blocking agent, to hamsters receiving a standardized traumatic lesion of the left uterine horn significantly inhibited primary adhesion formation as compared to control animals. These preliminary results suggest that calcium channel blockade may have the potential to favorably influence events related to peritoneal repair; further study of these agents as surgical adjuvants in the treatment of chronic pelvic adhesive disease is indicated.
Liver dysfunction in ovarian hyperstimulation syndrome. A case report.
Ovarian hyperstimulation syndrome (OHS) is one of the potential complications associated with the use of human menopausal gonadotropin therapy. We recently dealt with a case of severe OHS presenting features of liver dysfunction; such a case has not been reported on before.
Gonococcal pilin variants in experimental gonorrhea.
When pilus+ Gc were introduced into a male subject's urethra, they gave rise to pilus+ variants whose pilin mRNAs differed from that of input Gc. The differences stemmed from the Gc genome's single complete pilin gene having undergone gene conversion by different partial pilin genes' sequences and by different length stretches of a single partial pilin gene. In some instances, the variant's pilin mRNA appeared to reflect two independent gene-conversion events that used sequences from two different partial pilin genes. The resulting variants' pilins exhibited antigenic differences compared with the pilin polypeptide of input Gc; these differences were discernible by immunoblotting with mAbs. Amino acid and antigenic changes occurred in a segment of the variants' pilin polypeptides that previously was thought to be conserved or constant in sequence.
Gene conversion variations generate structurally distinct pilin polypeptides in Neisseria gonorrhoeae.
Pilus+ to pilus- phenotype change occurs in Neisseria gonorrhoeae through gene conversion of the gonococcus' complete, expressed pilin gene by nucleotides homologous to the pilS1 copy 5 partial pilin gene; assembly missense pilin is synthesized but pili are not. Reversion to pilus+ occurs by a subsequent recombinational event that replaces the complete pilin gene's pilS1 copy 5-like sequence with nucleotides from a different partial gene to effect expression of an orthodox (i.e., pilus producing) pilin. Sibling pilus+ revertants of common parentage can carry different sequences in their expressed pilin genes because they have undergone nonidentical gene conversion events such as recombinations with sequences from different partial genes, or recombinations with different length nucleotide stretches of the same partial gene; either can yield structurally and antigenically variant pilin polypeptides.
Gene conversion accounts for pilin structural changes and for reversible piliation "phase" changes in gonococci.
Pilus+ "wild-type" gonococci (Gc) frequently display gene conversion of their expressed complete pilin gene (CPG); a copy of DNA derived from one of the Gc genome's multiple silent partial pilin genes (PPG) is recombinationally-inserted into the CPG's central and 3' portions with formation of a new, chimeric CPG. Expression of that new CPG leads to either 1) retention of pilus+ phenotype but change in pilin primary structure/antigenicity, or 2) phase change to pilus- phenotype capable of reverting. This study utilizes pilus revertants of P-rp +/- Gc and P+ colony morphotype variants spawned by P++ Gc to examine pilin gene conversion in strain MS11mk Gc in greater detail. Each revertant's and variant's expressed pilin gene's sequence (as pilin mRNA) was defined to learn whether their differences are due to gene conversion by different PPGs, or by varying stretches from the same PPG, or both. Gene conversion by PPG pilS1 copy 2 has been documented in Gc recovered from a human volunteer's urethra previously inoculated with pilus Gc (strain MS11). The pilus+ Gc isolated expressed structurally/antigenically distinct pilins.
The effect of peritoneal fluid from patients with endometriosis on murine sperm-oocyte interaction.
It has been demonstrated that PF contains some factor or factors that interfere with effective gamete interaction as determined by an in vitro animal assay. PF from patients with mild endometriosis has an increased activity of this substance and/or additional inhibitory factors. In endometriosis, this peritoneal fluid factor or factors appear to be filterable and to a significant degree heat-labile. This observation may be of importance in explaining subfertility associated with early stages of endometriosis.
Tubular lysosome morphology and distribution within macrophages depend on the integrity of cytoplasmic microtubules.
Pinocytosis of the fluorescent dye lucifer yellow labels elongated, membrane-bound tubular organelles in several cell types, including cultured human monocytes, thioglycolate-elicited mouse peritoneal macrophages, and the macrophage-like cell line J774.2. These tubular structures can be identified as lysosomes by acid phosphatase histochemistry and immunofluorescence localization of cathepsin L. The abundance of tubular lysosomes is markedly increased by treatment with phorbol 12-myristate 13-acetate (10 ng/ml). When labeled by pinocytosis of microperoxidase and examined by electron microscopic histochemistry, the tubular lysosomes have an outside diameter of approximately 75 nm and a length of several micrometers; they radiate from the cell's centrosphere in alignment with cytoplasmic microtubules and intermediate filaments. Incubation of phorbol myristate acetate-treated macrophages at 4 degrees C or in medium containing 5 microM colchicine or nocodazole at 37 degrees C leads to disassembly of microtubules and fragmentation of the tubular lysosomes. Return of the cultures to 37 degrees C or removal of nocodazole from the medium leads to reassembly of microtubules and the reappearance of tubular lysosomes within 10-20 min. We conclude that microtubules are essential for the maintenance of tubular lysosome morphology and that, in macrophages, a significant proportion of the lysosomal compartment is contained within these tubular structures.
Tubular lysosomes accompany stimulated pinocytosis in macrophages.
A network of tubular lysosomes extends through the cytoplasm of J774.2 macrophages and phorbol ester-treated mouse peritoneal macrophages. The presence of this network is dependent upon the integrity of cytoplasmic microtubules and correlates with high cellular rates of accumulation of Lucifer Yellow (LY), a marker of fluid phase pinocytosis. We tested the hypothesis that the efficiency of LY transfer between the pinosomal and lysosomal compartments is increased in the presence of tubular lysosomes by asking how conditions that deplete the tubular lysosome network affect pinocytic accumulation of LY. Tubular lysosomes were disassembled in cells treated with microtubule-depolymerizing drugs or in cells that had phagocytosed latex beads. In unstimulated peritoneal macrophages, which normally contain few tubular lysosomes and which exhibit relatively inefficient transfer of pinocytosed LY to lysosomes, such treatments had little effect on pinocytosis. However, in J774 macrophages and phorbol ester-stimulated peritoneal macrophages, these treatments markedly reduced the efficiency of pinocytic accumulation of LY. We conclude that a basal level of solute accumulation via pinocytosis proceeds independently of the tubular lysosomes, and that an extended tubular lysosomal network contributes to the elevated rates of solute accumulation that accompany macrophage stimulation. Moreover, we suggest that the transformed mouse macrophage cell line J774 exhibits this stimulated pinocytosis constitutively.
Effects of recA mutations on pilus antigenic variation and phase transitions in Neisseria gonorrhoeae.
Intragenic recombination between the single complete pilin gene (expression locus) and multiple, distinct, partial pilin gene copies (silent, storage loci) is thought to account for the generation of pilus antigenic diversity and piliation phase (on-off) changes exhibited by Neisseria gonorrhoeae. The mechanisms operating in the genomic rearrangements associated with these forms of pilus variation were investigated through the study of isogenic strains of gonococci bearing either wild-type or altered recA alleles. Examination of the rates of pilus phase variation and the genetic basis for changes in piliation status displayed by these strains show that recA mediated homologous recombination is required for these high frequency events and confirm that the nonpiliated state results from mutations in the expressed pilin gene. In a strain that is deficient in recA mediated homologous recombination, pilus phase variation occurs at a 100-1000-fold reduced rate and results predominantly from one class of spontaneous frameshift mutations within the pilin structural gene.
Gm allotyping to determine the origin of the anti-D causing hemolytic anemia in a kidney transplant recipient.
Anti-D causing mild hemolytic anemia was found in the serum and on the red cells of a D-positive patient who had received a kidney transplant from his D-negative mother. Anti-D had been detected in the donor's serum before transplantation. Gm allotyping of the patient's serum, donor's serum, donor's anti-D, and the unexpected anti-D in the posttransplantation serum showed the antibody to be of maternal origin. The patient was Gm(fb), the donor Gm(agfb), the maternal anti-D Gm (afb), and the anti-D in the posttransplantation serum was Gm(a).
Antigens that are similar in apparent molecular weight to gonococcal outer membrane protein III.
Two immunoglobulin G monoclonal antibodies (MAbs) were produced by using purified outer membranes and whole gonococci as immunogens. These MAbs recognized antigens with similar apparent sizes (30 to 31.5 kilodaltons [kDa]) in several pathogenic and nonpathogenic neisseriae. In gonococci, these 30- to 31.5-kDa components, although similar in subunit size to outer membrane protein III (P.III), are distinct due to their differences in electrophoretic migration-modification by 2-mercaptoethanol and their cellular location. The two 30- to 31.5-kDa moieties are denoted by MAb2 and MAb3, respectively, by which they are identified. The differentiating characteristic of these three antigens (P.III, MAb2, MAb3) is their change or lack of change in electrophoretic mobility in the presence versus absence of 2-mercaptoethanol; P.III migrates less rapidly, MAb2 does not change, and MAb3 migrates more rapidly. Both the epitopes that were reactive with MAb2 and MAb3 were resistant to proteolytic treatment of intact gonococci; neither epitope was detected on whole, unfixed gonococci by immunofluorescence. Both MAb2 and MAb3 epitopes were represented uniformly among pathogenic neisseriae (except group Z meningococci) and less regularly among nonpathogenic neisseriae.