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Biomedical subjects

M Jansen

Publications and source records attributed to M Jansen.

195 records · Page 11Linked to original sources
PubMed1979

A new method for measuring antibody using radiolabeled protein A1 in a solid-phase radioimmunoassay.

A micro solid-phase radioimmunoassay was developed which utilizes radiolabeled staphylococcal Protein A ([125I]Protein A) in place of radiolabeled anti-immunoglobulin ([125I]anti-IgG) for the measurement of antibody. For the assay, antigen is adsorbed to the wells of a microtiter plate followed by dilutions of serum and [125I]-Protein A in subsequent steps. We found that this assay can be used to measure antibody (Ab) against a variety of antigens in human and rabbit but not goat immune serum. Binding of [125I]Protein A and [125I]anti-IgG to human and rabbit IgG was comparable. It was possible to quantify this amount of Ab in human serum by reference to immune rabbit serum. The sensitivity of this assay for rabbit antibody was 1 ng/ml.

Antibodies↗
PubMed1979

Xenobiotica-metabolizing enzymes in Drosophila melanogaster: activities of epoxide hydratase and glutathione S-transferase compared with similar activities in rat liver.

Activities of epoxide hydratase and glutathione (GSH) S-transferase were investigated in subcellular fractions of Drosophila melanogaster, and these activities were compared with analogous enzymic activities in extracts from rat liver. Microsomes of Drosophila were active in the hydratation of styrene oxide catalyzed by epoxide hydratase. The post-microsomal supernatant of Drosophila catalyzed the conjugation of GSH with 1-chloro-2,4-dinitrobenzene. However, GSH S-transferase activity with styrene oxide as the electrophilic substrate was not measurable. The respective specific activities of epoxide hydratase (per mg microsomal protein) and GSH S-transferase (per mg cytosolic protein) were factors of 5- and 10-fold lower than the corresponding activities in rat liver. However, when expressed per gram body weight, activities of both epoxide hydratase and GSH S-transferase were 3 times higher for Drosophila enzymes. The apparent Km values for the two Drosophila enzymes were higher, whereas the apparent Km values were lower, than the values found for the rat-liver enzymes. Among 3 different Drosophila strains (a wild-type, a white eye-color carrying mutant strain and a DDT-resistant strain), preliminary experiments showed no differences as far as these two enzymic activities were concerned. It is concluded that the results obtained in genetic toxicology testing with Drosophila are probably relevant to effects to be expected in mammalian systems with compounds requiring metabolic processes involving the enzymes investigated here.

Animals↗
PubMed1979

A solid-phase radioimmunoassay for the measurement of antibody to Aspergillus in invasive aspergillosis.

A solid-phase radioimmunoassay (SPRIA) to measure antibody responses to Aspergillus fumigatus and Aspergillus flavus antigens in invasive aspergillosis (IA) was developed and compared with immunodiffusion (ID) and counterimmunoelectrophoresis (CIE). SPRIA detected significant elevations in levels of aspergillus antibody in 15 (79)% of 19 patients with IA. Fewer patients with IA were positive by ID (give of 19) or CIE (four of 19). Only seven )8%) of 58 subjects with other fungal or bacterial infections were positive by SPRIA, as was one (5%) of 20 by ID and CIE. Weak cross-reactivity between aspergillus and candida antigens was demonstrated by SPRIA. IgG levels in patients with IA and control subjects were equivalent. Thus, an antibody response to Aspergillus can be detected in a greater percentage of patients with IA by SPRIA than by ID or CIE. Although a few patients without aspergillosis had elevated levels of aspergillus antibody, a rise in antibody level was specific for IA.

Adolescent↗
PubMed1978

Antibody to Tamm-Horsfall protein in patients with urinary tract obstruction and vesicoureteral reflux.

Urinary tract obstruction and vesicoureteral reflux, which are often associated with urinary tract infections, may lead to progressive renal damage. Relatively little is known about the pathophysiology of this process, and a need exists for noninvasive methods of its detection in its early stages. Because urine is refluxed into the venous and lymphatic drainage of the kidney in severe vesicoureteral reflux and urinary tract obstruction, an immune response to urinary tract components might play a role in the pathophysiology of progressive renal damage and serve as a serologic marker for its presence. A solid-phase radioimmunoassay for a protein found only in the urine (Tamm-Horsfall protein [THP]) was developed and used to measure antibody to THP in the serum of 60 subjects. Significant elevations of antibody to THP were observed in five of 15 patients with obstruction and infection of the urinary tract and in one of 10 patients with infection alone, when these patients were compared with 12 healthy control subjects. Similar elevations of antibody to THP were not seen in uninfected patients with urinary tract obstruction or in patients with low-grade vesicoureteral reflux or sepsis of nonrenal origin. These results suggest that the measurement of antibody to THP might be useful in the identification of patients with obstruction and infection of the urinary tract.

Adolescent↗
PubMed1967

Polyamines and the accumulation of ribonucleic acid in some polyauxotrophic strains of Escherichia coli.

The cellular accumulations of polyamines and ribonucleic acid (RNA) were compared in the polyauxotrophic mutants of Escherichia coli strain 15 TAU and E. coli K-12 RC(re1) met(-) leu(-). Putrescine, spermidine, and their monoacetyl derivatives were the main polyamines in both strains, when grown in glucose-mineral medium. No significant degradation of either (14)C-putrescine or (14)C-spermidine was found in growing cultures of strain 15 TAU, which requires thymine, arginine, and uracil for growth. Experiments with this organism showed that in a variety of different incubation conditions, which included normal growth, amino acid starvation, inhibition by chloramphenicol or streptomycin, or thymine deprivation, a close correlation was seen between the intracellular accumulation of unconjugated spermidine and RNA. In the presence of arginine, the antibiotics stimulated the production of putrescine and spermidine per unit of bacterial mass. Deprivation of arginine also resulted in an increase in the production of putrescine per unit of bacterial mass, most of which was excreted into the growth medium. However, in this system the antibiotics reduced the synthesis of putrescine. Furthermore, streptomycin caused a rapid loss of cellular putrescine into the medium. The latter effect was not seen in anaerobic conditions or in a streptomycin-resistant mutant of 15 TAU. Methionine added to the growth medium of growing TAU not only markedly increased the total production of spermidine, but also increased both the intracellular concentration of spermidine and the accumulation of RNA. Exogenous spermidine extensively relaxed RNA synthesis in amino acid-starved cultures of 15 TAU. Analysis in sucrose density gradients showed that the RNA accumulated in the presence of spermidine was ribosomal RNA. Cells of E. coli K-12 RC(rel) met(-) leu(-), grown in a complete medium, had approximately the same ratio of free spermidine to RNA as did strain 15 TAU. However, the relaxed strain showed a much lower ratio of putrescine to spermidine than the stringent 15 TAU. Omission of methionine stopped spermidine synthesis and markedly increased both the intracellular accumulation and the total production of putrescine. It seems that a high intracellular level of spermidine acts as a feedback inhibitor in the biosynthesis of putrescine in this strain. The hypothesis that the intracellular concentration of polyamines may participate in the control of the synthesis of ribosomal RNA in bacteria is discussed.

Amides↗
PubMed1966

Polymer synthesis in killed bacteria: lethality of 2',3'-dideoxyadenosine.

Doering, Alice McGovern (University of Pennsylvania School of Medicine, Philadelphia), Miekie Jansen, and Seymour S. Cohen. Polymer synthesis in killed bacteria: lethality of 2',3'-dideoxyadenosine. J. Bacteriol. 92:565-574. 1966.-We studied the metabolic capabilities of cells that had lost the ability to multiply under a variety of lethal treatments. Cultures of a polyauxotrophic mutant of Escherichia coli strain 15 requiring thymine, arginine, uracil, and adenine for growth were killed to a few per cent survivors by several different methods. These treatments included streptomycin, thymineless death, d-arabinosyladenine (ara-A), and 2',3'-dideoxyadenosine (DDA). The killed cells were washed and supplied with complete media, and were compared with control cells with respect to the ability to incorporate thymine, arginine, and uracil. Cells killed with streptomycin in the absence of thymine were only partially inhibited in deoxyribonucleic acid (DNA) synthesis; they were markedly inhibited in synthesis of ribonucleic acid (RNA) and protein. Cells that had suffered thymineless death were essentially uninhibited in DNA synthesis, partially so in RNA synthesis, but extensively inhibited in protein synthesis. Killing by ara-A did not prevent DNA synthesis, but markedly inhibited RNA and protein synthesis. The lethality of DDA was studied in the presence of exogenous adenosine; lethality was partially prevented by deoxyadenosine. Dideoxyadenosine was similar to ara-A and thymineless death in killing in a pattern in which RNA and protein synthesis continued while DNA synthesis was inhibited. Cells killed by DDA, however, were markedly inhibited in subsequent thymine incorporation, unlike cells killed by the other methods. In addition, at this time, the DDA-killed cells were more inhibited in incorporation of arginine than of uracil. DDA also potentiated thymineless death; when cells were killed rapidly by the combined treatment, only the ability to synthesize DNA was lost irreversibly. This agent (DDA) may permit the detailed study in E. coli of the relation of DNA synthesis to numerous phenomena, such as genetic recombination, sequential transcription, and the number and distribution of chromosome breaks.

Adenine↗
PubMedDate not supplied

Sequence of cDNA encoding human insulin-like growth factor I precursor.

Somatomedins (SM) or insulin-like growth factors (IGF) constitute a heterogeneous group of peptides with important growth-promoting effects in vitro as well as in vivo. Amino acid sequences have been determined for only two of them, IGF-I and IGF-II, which are highly homologous. IGF-I, which is identical with SM-C, is composed of 70 amino acid residues and IGF-II contains 73 amino acids and may be identical with SM-A. Other peptides with different charge properties but with similar SM-like or insulin-like behaviour in biological and receptor assays, have been described but have not yet been fully characterized. The liver is known to be a major site of production of these peptides, but many other tissues--especially in the fetus--may synthesize them as well. We report here the nucleotide sequence of a human liver cDNA encoding the complete amino acid sequence of IGF-I. The IGF-I coding region is flanked by sequences encoding an amino-terminal peptide of at least 25 amino acid residues and a carboxyl-terminal peptide of 35 amino acids. This provides evidence that IGF-I is synthesized as a precursor protein and that formation of IGF-I from this precursor requires proteolytic processing at both ends.

Base Sequence↗
PubMedDate not supplied

Surgical mesh as a scaffold for tissue regeneration in the esophagus.

BACKGROUND: Textiles in the form of surgical meshes are widely used in hernia surgery. Their porous structure allows tissue infiltration to incorporate the fabric for complete healing and device stabilization. This study was aimed to reconstitute the esophageal wall and to investigate the functional and histological consequences of a new, non-absorbable polyvinylidene fluoride (PVDF) mesh and an absorbable polyglactin 910 (Vicryl((R))) mesh. METHODS: Semicircular esophageal defects of 0.5 x 1 cm were created 2 cm proximal of the cardia in 10 rabbits. This gap was bridged using either polyglactin 910 or PVDF and additionally covered by omental wrapping. The clinical outcome was observed by clinical observation, regular esophagoscopies and X-ray contrast medium examinations. Local tissue regeneration was verified by light microscopy and immunohistochemistry. RESULTS: After an observation period of 3 months we found no anastomotic strictures, complete mucosal regeneration, minimal inflammation reaction and initial regeneration of the muscle layer for the PVDF group. Within the polyglactin 910 group, three patch failures with consecutive anastomotic leakage occurred. CONCLUSION: The results indicate that PVDF mesh structure gives the opportunity of local tissue regeneration in the esophagus. Though re-epithelialization and muscle cell ingrowth could be detected for absorbable polyglactin 910 mesh, this implant was accompanied by a high and early rate of anastomotic leakage.

Animals↗
PubMedDate not supplied

Control of glial cell volume in anoxia. In vitro studies on ischemic cell swelling.

Volume regulation of C6 glial cells was studied in anoxia in vitro to improve the understanding of ischemic cell swelling in the brain. Contrary to in vivo conditions, anoxia or anoxia plus iodoacetate for additional inhibition of anaerobic energy metabolism did not induce glial swelling. However, intracellular K+ was markedly decreased while intracellular Na+ increased. Induction of energy failure by anoxia plus iodoacetate was found to prevent the regulatory volume decrease on hyposmotic exposure of the cells, which is regularly observed in normoxic control conditions. Hyposmotic exposure in anoxia plus iodoacetate led only to an initial tendency of cell volume normalization followed by secondary cell swelling. This was associated with a net increase of intracellular Na+ that may explain the failure of volume regulation under these circumstances. Maintenance of a normal glial cell size during complete energy deprivation by anoxia plus iodoacetate in isotonic medium strongly indicates that energy failure per se does not suffice to induce cell swelling. Cell swelling in cerebral ischemia in vivo thus is likely to require additional mechanisms, most likely an increase of membrane permeability to Na+, which may be caused by release and accumulation of excitotoxins such as glutamate or by an extracellular release of K+. Such a mechanism would hardly influence the extracellular homeostasis in vitro due to the large medium-to-cell volume ratio. The findings demonstrate, nonetheless, the significance of a competent energy metabolism to support cell volume regulation. This is concluded from the failure of regulatory volume decrease of hypotonically suspended glial cells in anoxia plus iodoacetate.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Line↗