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Biomedical subjects

R Fritz

Publications and source records attributed to R Fritz.

At least 37 records · Page 2Linked to original sources
PubMed1985

Urinary bladder glycoproteins of the rabbit: extraction, biochemical and immunological studies.

The mucin layer of the bladder covering the transitional epithelium is thought to be an anti-adherence substance for bacteria. We have previously demonstrated that removal of this layer results in increased bacterial colonization. In this present communication we report our attempts to isolate and characterize the components of the mucin layer. Bladders were removed from female NZW rabbits and the mucosal layer was extracted with 0.1 M NaCl. Fractional centrifugation and column chromatography on AcA 34 and AcA 22 resulted in the separation of a partially purified glycoprotein, containing 30% carbohydrate, migrating as a single peak (4.5S) in the analytical ultracentrifuge. It was immunogenic in mice and the antisera were used to develop both a radioimmunoassay and an enzyme linked immunosorbent assay (ELISA). The antigenic activity of the glycoprotein was destroyed by protease or extremes of pH, but not by several glycosidases. In addition the murine antisera could not be inhibited by a panel of naturally occurring glycoproteins or glycosaminoglycans.

Animals↗
PubMed1985

Specificity of T lymphocyte lines for peptides of myelin basic protein.

T lymphocyte lines specific for myelin basic protein (BP) can mediate experimental autoimmune encephalomyelitis (EAE), or can protect against the active induction of the disease. To investigate the antigenic fine specificity of guinea pig (GP) BP-specific T cell lines raised from different rat strains, and to determine whether functionally different T lymphocyte lines and clones recognized the same or different regions of the BP molecule, the proliferation responses of line cells were assessed after stimulation with purified peptides of GP-BP. Lewis rat T cell lines and clones selected for responses to whole GP-BP responded selectively to the 68-88 amino acid sequence of GP-BP, but not to the 1-37, 43-67, or 89-169 sequences. The region of GP-BP recognized by Lewis T cells was additionally defined to include the 75-80 amino acid sequence, because a T cell clone responded equally to GP and rat BP which differed by only one amino acid at position 79, but did not respond to human or bovine BP, which had a Gly-His insertion in this region. T lymphocyte lines derived from the F344 and PVG (Weizmann) rat strains shared the same selective response to peptide 68-88, but lines from BN rats responded to an epitope(s) outside of the 68-88 sequence. The functional capacity of the various T cell lines to mediate experimental autoimmune encephalomyelitis (EAE) or to induce resistance against EAE was independent of their specificity for the different GP-BP peptides; lines specific for epitope(s) within or excluded from the 68-88 sequence could be encephalitogenic depending on their strain of origin, and various lines specific for the 68-88 peptide could induce both disease and protection, disease only, or neither activity.

Animals↗
PubMed1983

A DNA recombinant database management system.

A set of computer programs is described which constitutes a clone database management system. Maintenance of the database and the stocks of material is designed to be under the control of one person or group of people, who may insert, delete or modify data entries, and who may interrogate the database as to which stocks are in need of checking. The system is organised in such a way that information is freely and speedily available to all users. Database entries may be accessed by name or key word.

Animals↗
PubMed1980

Antimicrobial sensitivities in urinary tract infections in men.

Six-thousand-seven-hundred and forty-nine positive urine cultures from a large metropolitan Veterans Administration hospital were analyzed with respect to the organisms isolated and their antimicrobial sensitivities. A "predicted therapeutic efficacy index" was calculated for each antimicrobial agent tested. Gram-negative pathogens accounted for 84% of the infections. Proteus infections outnumbered those due to strains of Escherichia coli. Gentamycin was found to be the most effective antimicrobial agent.

Ampicillin↗
PubMed1978

Heparin as antibacterial agent in rabbit bladder.

Previous studies performed in our laboratory indicated that the primary antibacterial defense mechanism of the rabbit bladder is the antiadsorptive action of the surface mucopolysaccharide. The increased bacterial adsorption that occurs when the bladder is denuded of this layer was prevented by the instillation of heparin. Additional studies showed that the protective effect of heparin is inhibited by protamine, a further indication that the bladder's "antiadherence factor" is a mucopolysaccharide. Small amounts of heparin, applied directly to the mucoprotein-deficient bladder or to the surface of the inoculated bacteria, produced a statistically significant reduction in bacterial adsorption.

Adsorption↗
PubMedDate not supplied

T-cell clones specific for myelin basic protein induce chronic relapsing paralysis and demyelination.

Experimental allergic encephalomyelitis (EAE) serves as a model for autoimmune diseases mediated by T lymphocytes. Following sensitization to rat, mouse or guinea pig myelin basic protein (MBP) in complete Freund's adjuvant, inbred mouse strains PL/J (H-2u), SJL/J (H-2s) and (PL/J X SJL/J)F1((PLSJ)F1) develop EAE. Whereas sensitization to the N-terminal 37 amino-acid peptide of rat or guinea pig MBP [MBP(1-37)] induces EAE in PL/J mice, immunization to the C-terminal peptide (89-169) leads to EAE in SJL/J mice. The immune response to MBP in (PLSJ)F1 mice is not co-dominant; sensitization to the N-terminal peptide induces EAE, while sensitization to the C-terminal peptide does not. We have generated MBP-specific T-cell clones restricted to class II (Ia) antigens of the major histocompatibility complex (MHC) from PL/J and (PLSJ)F1 mice following sensitization to rat MBP. Two such I-Au-restricted T-cell clones that proliferate in response to the encephalitogenic N-terminal MBP peptide and recognize a shared determinant with mouse (self) MBP cause paralysis in 100% of (PLSJ)F1 mice tested. Paralysis is induced even when recipients are injected with as few as 1 X 10(5) cloned T cells. Relapsing paralysis followed in two-thirds of the recipients after recovery from acute paralysis, whereas one-third developed chronic persistent paralysis, a form of EAE not usually seen. Histopathology revealed intense perivascular inflammation, demyelination and remyelination within the central nervous system of paralysed mice. The experimental disease induced with these clones shares important features with human demyelinating diseases such as multiple sclerosis. This is the first demonstration that T-cell clones that respond to a defined self-antigen can induce clinical and histological autoimmune disease.

Animals↗
PubMedDate not supplied

How to keep your best people for the '90s.

Getting good people to join us merely sets the stage for achievement. the real payoff depends on how we deal with them and how long they stay. From the CEO's perspective, the most important requirements for the '90s are: Know what you mean by performance in all jobs, in all functions, and at all levels. Hire accountable people. Know what it takes to hire and keep the best people and do it. Invest what it takes to fill at least 70% of your promotions with people from the inside; they will consistently perform better than outsiders. Weed out non-performers promptly and as religiously as you seek outstanding new people. Have a human resource plan in place before you grow beyond your people's capability to deliver. Build a strong, active, useful board of directors to provide an objective perspective on your actions as CEO and on the development of the company. Do not try to clone yourself. Hire people who are better than you and keep them as long as you can. Listen to them; invest in them; and benefit from them, so that when you are ready for retirement, you can sit on their board of directors.

Career Mobility↗