Search PubMed⌕ Search

Biomedical subjects

D J Anderson

Publications and source records attributed to D J Anderson.

At least 415 records · Page 23Linked to original sources
PubMed1983

Transmembrane orientation of an early biosynthetic form of acetylcholine receptor delta subunit determined by proteolytic dissection in conjunction with monoclonal antibodies.

The transmembrane topology of acetylcholine receptor (AChR) delta subunit, synthesized in vitro and co-translationally integrated into dog pancreas rough microsomal membranes, was studied using limited proteolysis and domain-specific immunoprecipitation. Forty-four kilodaltons (kd) of the 65-kd delta subunit comprise a single fragment that is inaccessible to exhaustive proteolytic digestion from the cytoplasmic surface of the membrane by trypsin, chymotrypsin, thermolysin, and pronase. Previously, we have shown that this 44-kd "protected" fragment contains the amino terminus of the intact molecule and all of the core oligosaccharides (Anderson, D.J., P. Walter, and G. Blobel (1982) J. Cell Biol. 93: 501-506). Here we demonstrate that this domain can be further dissected into a 26-kd fragment, together with low molecular weight material, when the membranes are rendered permeable to trypsin by low concentrations of deoxycholate (Kreibich, G., P. Debey, and D. D. Sabatini (1973) J. Cell Biol. 58: 436-462). This 26-kd fragment contains all of the core oligosaccharides present on the intact subunit and therefore constitutes at least part, if not all, of the extracellular domain. The remaining low molecular weight material may derive from the membrane-embedded domain; our data imply that as much as 18 kd may be internal to the lipid bilayer. On the other hand, part of the cytoplasmic pole of AChR-delta can be recovered as a discrete, 12-kd fragment upon mild trypsinization of intact vesicles. We have used this 12-kd fragment to identify anti-AChR-delta monoclonal antibodies (mAbs) that react with the cytoplasmic domain of this subunit. Partial proteolytic fragmentation of the AChR in vitro translation products, in topologically well defined rough microsomes, may be used as a general assay to characterize the domain specificity of anti-AChR mAbs. For example, in the case of AChR-beta, we were able to identify two mAbs that recognize extracellular and cytoplasmic fragments, respectively.

Animals↗
PubMed1983

Spontaneous tumors in long-term--vasectomized mice. Increased incidence and association with antisperm immunity.

In two independent studies the authors have observed a significantly higher incidence of spontaneous tumors in vasectomized BDF1 mice over the long term than in age-matched sham-vasectomized control mice. In the first study, necropsies were performed on the animals at 30 months of age (27 months after surgery), and 15 of 24 vasectomized versus 2 of 14 sham-vasectomized mice (P less than or equal to 0.025) had detectable tumors in various tissues. In a second study, necropsies were performed on the animals at a younger age (18 months, 15 months after surgery), and liver tumors predominated: 82 of 171 vasectomized versus 33 of 97 controls (48% versus 34%, P less than or equal to 0.037) had at least one hepatic tumor, and a significantly higher percentage of vasectomized animals had large (greater than or equal to 31 sq mm) hepatic tumor burdens (80% versus 49%; P less than or equal to 0.002) and multiple hepatic tumors (19% versus 5%; P less than or equal to 0.002). In combined data from both studies, the vasectomy group had a higher incidence of (1) at least one tumor (P less than or equal to 0.025), (2) multiple tumors (P less than or equal to 0.005), and (3) more than one type of tumor (P less than or equal to 0.05. Furthermore, in both studies tumor number and size were significantly associated with antisperm immunity detected by antibody or aspermatogenesis evaluation. It is speculated that sperm degradation products and/or the autoimmune response to sperm that commonly accompanies vasectomy may affect tumor induction or growth directly or indirectly by interfering with immunosurveillance mechanisms.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1983

Retinoblastoma. HLA expression induced by retinoic acid.

The full expression of Class 1 antigens of the major histocompatibility complex (HLA A,B,C,) on ocular cell surfaces appears to be developmentally regulated; HLA is undetectable in retina from 16-week-old fetal eyes but is present in adult retina. Cultured retinoblastoma (RB) may serve as a useful model of retinal cell development. SF81 is an undifferentiated subculture of in vitro retinoblastoma with little evidence of spontaneous differentiation and lack of expression of HLA, attesting to the "undifferentiated" character of this cell line. RB SF81 cells were treated with retinoic acid, a known stimulator of differentiation (optimal concentration 5 X 10(-8) M). HLA expression was evaluated with immunofluorescence, immunoperoxidase, and radioimmunoassay, using monoclonal antibodies. RB SF81 treated with retinoic acid showed a significant, persistent increase in HLA levels by 24 hours compared with controls. Thus, retinoic acid has been documented to induce the surface expression of HLA in undifferentiated retinoblastoma. Developmental parallels between embryonic retina and in vitro retinoblastoma treated with retinoic acid exist.

Antibodies, Monoclonal↗
PubMed1983

Antisperm antibodies in mouse vasectomy sera react with embryonal teratocarcinoma.

Sera from vasectomized BDF1 mice were tested by immunofluorescence and radioimmunoassay for antibodies reacting with sperm and the mouse teratocarcinoma cell lines F9 and PYS. Antibody titers to both sperm and F9 cells increased with time after vasectomy and were highest in long-term (15 to 30 mo) vasectomized animals. By immunofluorescence assay, 35% of long-term vs 10% of age-matched control mice had antisperm antibodies (p less than or equal to 0.01), 54% of vasectomized vs 21% of controls had antibodies reacting with F9 teratocarcinoma (p less than or equal to 0.01), and 5% of vasectomized vs no controls reacted to the PYS teratocarcinoma cell line. No sera from either group reacted with thymocytes or cultured fibroblasts from male 129/Sv mice (negative somatic cell controls). Kendall's rank order statistical correlation test showed a significant association (p less than or equal to 0.01) between individual responses to sperm and F9 cells. Absorption of positive sera with sperm removed both sperm and F9 reactivity, indicating that the F9 cell-reactive antibodies in vasectomy sera are directed against identical or immunologically cross-reactive antigens present on the surface of sperm and F9 embryonal teratocarcinoma. A combination of electrophoresis and nitrocellulose blotting techniques (Western blot analysis) revealed that sera from some vasectomized mice contain IgG antibodies that react with 50,000 and 150,000 dalton (approximately) antigen bands present in sperm and F9 extracts, but not in PYS or thymocyte extracts. It remains to be determined whether the teratocarcinoma antigens detected in this study are true embryonic antigens or germinal antigens (the F9 cell line may have originated from primordial germ cells in transplanted embryonic tissue). In either case, teratocarcinoma cell lines provide an abundant source of material for the further characterization of these autoantigenic molecules.

Absorption↗
PubMed1982

Percutaneous central venous catheterization performed by medical house officers: a prospective study.

We prospectively determined the complications of percutaneous central venous catheterizations performed by medical house officers in 302 patients. We also analyzed the factors affecting the success and complication rates of such invasive procedures. The central vein was successfully catheterized in 363 (77%) of 470 attempts. The internal jugular and subclavian vein approaches were significantly more successful (86%) than the external jugular vein approach (61%, P less than 0.001 by chi 2). The success rate improved significantly when catheterization was attempted under elective circumstances (P less than 0.003) and also after the vein was initially located with a small-gauge needle (P less than 0.001). Our results suggest that efforts should be abandoned after the third unsuccessful pass with a large-gauge needle in the same site. Complications of catheter insertion included bleeding (ten patients), hematoma (15 patients), inadvertent arterial punctures (14 patients), iatrogenic pleural effusions (four patients), and pneumothoraces (eight patients). No complications appeared to have a major adverse effect on a patient's clinical course. The inexperienced operator (fewer than 25 prior catheterizations) has a success rate equal to that of the more experienced operator (more than 25 prior catheterizations), but he may be more likely to produce a complication. Medical house officers can perform percutaneous central venous catheterizations with a high rate of success and a low risk to the patient.

Arteries↗
PubMed1982

Intraocular penetration of topically applied [14C]fosfonet sodium in rabbits.

The intraocular penetration of [14C]fosfonet was studied following topical application of 25 mg of an ointment containing 5% [14C]fosfonet sodium onto the intact and abraded eyes of New Zealand white rabbits. Radioactivity penetrated rapidly through the abraded cornea and entered the anterior chamber. The concentration of fosfonet in the aqueous humor peaked at 7.2 microgram/ml by 90 min. Assuming an aqueous humor volume of 300 microliter, this level would correspond to approximately 0.2% of the applied dose. The highest concentration of fosfonet found in the abraded cornea was 0.3 microgram/mg, or 0.4% of the applied dose. The half-lives for the elimination of fosfonet from the aqueous humor and cornea were about 2.5 and 2.7 hr, respectively. The fosfonet levels in the iris were extremely low throughout the 6-hr period. The penetration of [14C]fosfonet through the intact cornea was considerably less than that found in the abraded eye. The peak concentrations of fosfonet in the aqueous humor and cornea of the intact eye were 0.26 microgram/ml and 0.02 microgram/mg, respectively, and occurred within 10 min of application of ointment.

Administration, Topical↗
PubMed1982

A specific estrogen receptor in the mouse spleen. Characterization and evidence of physiological regulation.

We have used the synthetic estrogen [3H]-R2858 (11 beta-methoxy-17-ethnyl-1,3,5(10)-estratriene-3,17-diol) to characterize a cytoplasmic estrogen receptor in the mouse spleen. This receptor is specific for estrogens and binds to the steroids with high affinity. The binding is abolished by pronase or 37 C treatment, and the 8S peak is shifted to the 4S region on sucrose gradients under conditions of high salt. The concentration of spleen receptor increased significantly during pregnancy, and decreased after immunization with foreign protein. Estrogen receptors may be confined to certain subpopulations of spleen cells that change in numbers during pregnancy or after immunization.

Animals↗
PubMed1982

Comparative analysis of the major polypeptides from liver gap junctions and lens fiber junctions.

Gap junctions from rat liver and fiber junctions from bovine lens have similar septilaminar profiles when examined by thin-section electron microscopy and differ only slightly with respect to the packing of intramembrane particles in freeze-fracture images. These similarities have often led to lens fiber junctions being referred to as gap junctions. Junctions from both sources were isolated as enriched subcellular fractions and their major polypeptide components compared biochemically and immunochemically. The major liver gap junction polypeptide has an apparent molecular weight of 27,000, while a 25,000-dalton polypeptide is the major component of lens fiber junctions. The two polypeptides are not homologous when compared by partial peptide mapping in SDS. In addition, there is not detectable antigenic similarity between the two polypeptides by immunochemical criteria using antibodies to the 25,000-dalton lens fiber junction polypeptide. Thus, in spite of the ultrastructural similarities, the gap junction and the lens fiber junction are comprised of distinctly different polypeptides, suggesting that the lens fiber junction contains a unique gene product and potentially different physiological properties.

Animals↗
PubMed1982

Signal recognition protein is required for the integration of acetylcholine receptor delta subunit, a transmembrane glycoprotein, into the endoplasmic reticulum membrane.

Purified Signal Recognition Protein (SRP) has previously been shown to be required for the translocation of secretory proteins across the microsomal membrane (Walter and Blobel, 1980. Proc. Natl. Acad. Sci. U. S. A. 77:7, 112-7, 116) and to function in the early events of this process (Walter and Blobel, 1981. J. Cell Biol. 91:557-561). We demonstrate here that the delta subunit of acetylcholine receptor (AChR-delta), a transmembrane glycoprotein, likewise requires SRP for its asymmetric integration into microsomal membranes. We further demonstrate by partial sequence analysis that AChR-delta is synthesized with a transient NH2-terminal signal sequence of 21 residues that is cleaved off during integration into microsomal membranes. Integration of AChR-delta into the microsomal membrane vesicles proceeded asymmetrically, yielding a large (44 kdalton) core-glycosylated domain, inaccessible to externally added proteolytic enzymes and a smaller (approximately 16 kdalton) domain exposed on the outside of the vesicles and accessible to externally added proteolytic enzymes. The NH2 terminus of the molecule is contained in the 44-kdalton domain.

Amino Acid Sequence↗
PubMed1982

Urinary tract infection due to coagulase-negative staphylococcus.

One hundred and fifty-six urine specimens with a pure culture of coagulase-negative Staphylococcus were studied. One hundred and eighteen charts were reviewed for clinical evidence of urinary tract infections. Twenty-four cases of urinary tract infection were found. The younger females in the study tended to have infection due to novobiocin resistant Staphylococcus in contrast to males and older females.

Adolescent↗
PubMed1982

Antibodies to antigens on teratocarcinoma cells are associated with parity in mice.

Previous studies have demonstrated that the maternal host responds immunologically to antigens of the fetus, including oncofetal antigens (OFA). However, until now, the OFA that have been studied are those associated with the postimplantation embryo. In this paper we provide evidence that the maternal host also responds immunologically to antigens associated with the mouse teratocarcinoma (TC) cell lines F9 and PYS-2, which have been established as models for the preimplantation embryo. In a solid-phase radioimmunoassay using cell membrane extracts as antigen and 125I-protein A to detect binding antibodies, sera from parous C57BL/6 mice had a significantly greater reactivity than sera from age-matched virgin animals to F9 but not PYS-2, splenocyte or fibroblast antigen extracts. This finding was confirmed by surface immunofluorescence (IF) with fluorescein-labeled anti-mouse IgG. IF also detected a small number of multiparous mice with antibodies to PSY-2. Positive serum reactivity did not correlate directly with the number of previous litters. These TC cell lines express at least 2 OFA, F9 and Endo, which are found on preimplantation embryos and sperm, and preimmunization of female mice with F9 cells has been shown to reduce fertility. The parity-induced antibodies detected in this study could react with embryos at early stages of development and contribute to the natural decrease in litter size which occurs in mice after the second litter.

Animals↗
PubMed1982

Immunity to tumor-associated antigens in vasectomized men.

Leukocytes from 49 vasectomized and 57 age-matched nonvasectomized men were tested in the leukocyte adherence inhibition (LAI) assay for reactivity to sperm and various 3-M KCl human tumor extracts. Forty-four percent of the vasectomized men and 15% of the control group were reactive to the sperm antigen preparation (P less than or equal to 0.03). Similarly, a significantly higher percentage of vasectomized men responded to 3 of 5 tumor extracts tested: melanoma I (34.7 vs. 15.8%, P less than or equal to 0.04), squamous cell carcinoma (48.8 vs. 26.0%, P less than or equal to 0.04), and breast carcinoma (19.5 vs. 4%, P less than or equal to 0.04). Thirty percent of vasectomized versus 4% of the control group responded to more than two tumor antigens (P less than or equal to 0.03). The degree of LAI reactivity to each tumor extract was highly correlated with degree of antisperm LAI reactivity, and the degree of LAI responsiveness to one of the melanoma extracts was significantly correlated with antisperm antibody titer as measured by the sperm-immobilization assay. Furthermore, nonresponsive leukocytes from the control population converted to tumor antigen-responsive when incubated with sera from vasectomized LaI-positive men. Data from this study indicated that a large percentage of vasectomized men with sperm immunity were responsive to tumor-associated antigens in the LAI test and that antisperm antibodies or other serum factors played a role in this response. These results and the evidence that most tumor antigen-responsive cancer patients also have serum antibodies that reacted with sperm suggested that vasectomized men and cancer patients frequently responded to immunologically cross-reactive antigenic determinants present on both sperm and tumor cells.

Antibodies↗