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Biomedical subjects

R Wagner

Publications and source records attributed to R Wagner.

At least 37 records · Page 2Linked to original sources
PubMed1991

Organ-specific cardiac antibodies: serological markers for systemic hypertension in autoimmune polyendocrinopathy.

Circulating organ-specific autoantibodies are serological markers of destruction or impairment of the relevant endocrine tissue cells and may be associated with abnormal hormone levels with or without clinical evidence of overt disease. We sought organ-specific cardiac antibodies in patients with autoimmune polyendocrinopathy because of increasing evidence that the heart has endocrine characteristics (secretion of atrial natriuretic peptide [ANP] and other peptide hormones). Serum samples from 166 patients with polyendocrinopathy, 80 with autoimmunity confined to one gland, and 200 healthy blood donors were tested for these antibodies by means of immunofluorescence on human heart. Skeletal muscle was used to identify cross-reacting antibodies. Organ-specific cardiac antibodies were detected in significantly more of the patients with autoimmune polyendocrinopathy (28 [17%]) than of those with autoimmunity confined to one gland (1 [1%]) or of normal subjects (7 [3.5%]; p = 0.0001). Among the patients with autoimmune polyendocrinopathy, the prevalence of systemic hypertension was higher in those with cardiac autoantibodies than in those without (5/28 [18%] vs 2/80 [3%]; p = 0.01); the same was true for a family history of hypertension (11 [42%] vs 5 [7%]; p = 0.0001). There were no significant differences in mean basal or stimulated ANP concentrations between patients with or without antibodies or between patients and controls. 5 of the 22 antibody-positive patients had ANP concentrations outside the normal range, but these disturbances were not associated with systemic hypertension or a family history of the disorder. Patients with autoimmune polyendocrinopathy can have organ-specific cardiac antibodies, which may represent novel serological markers for an autoimmune form of systemic hypertension in the absence of overt cardiac disease.

Adult↗
PubMed1991

The effect of postoperative radiation therapy on pharyngoesophageal reconstruction with free jejunal interposition.

Free tissue transfer of a jejunal segment was undertaken for laryngopharyngoesophageal reconstruction in 20 patients who received postoperative irradiation therapy. Treatment consisted of 1.8- to 2-Gy-fractions, the average total dose was 55.57 Gy (range, 40 to 66 Gy). Anastomotic strictures (six) were encountered early in the series and associated with stapled anastomoses. Hand-sewing the jejunoesophagostomy eliminated the problem. Enteric cutaneous fistula, bowel necrosis, and hemorrhagic enteritis were not observed. We conclude that the application of postoperative irradiation therapy to patients requiring jejunal interposition grafts is feasible.

Adolescent↗
PubMed1991

Enzyme sensor-FIA-system for on-line monitoring of glucose, lactate and glutamine in animal cell cultures.

Enzyme sensors for glucose, lactate and glutamine were connected via flow-injection analysis (FIA) devices to two different bioprocesses. They were used for on-line process control of perfused bioreactor systems containing mammalian cell lines producing a monoclonal antibody and recombinant interleukin-2. The biosensor system gives direct access to important process data which can be used as control parameters for long term cell cultivation systems.

Animals↗
PubMed1990

A quantitative assessment for transcriptional pausing of DNA-dependent RNA polymerases in vitro.

A simple definition for pause strength (tau i) has been given, quantitatively describing transcriptional pausing of RNA polymerases. It permits derivation of practical assessments, based on single-round transcription reactions, which measure the average time a polymerase stops in vitro at certain sites during transcription elongation. We demonstrate that pause strengths can be determined with high accuracy when transcription elongation is started simultaneously from radioactively labeled and purified ternary complexes and transcripts are separated on sequencing gels. Our concept is exemplified by measuring pause strengths on supercoiled templates in the leader region of the Escherichia coli rrnB operon in the presence and the absence of the transcription factor NusA.

Bacterial Proteins↗
PubMed1990

Watching G proteins at work.

It has been known for over a century that rod photoreceptors in the living retina contract and swell in response to light. Although it is still not known whether this structural light-response is of any functional significance, it has recently been possible to correlate the underlying molecular processes with the activation and deactivation of the photoreceptor G protein, transducin. The technique of light-scattering allows the monitoring of minute changes in cell dimensions, and using this non-invasive experimental approach it can be shown that certain properties of the coupling between transducin and rhodopsin are different in a structurally well-preserved system as compared with rod material used for conventional biochemical studies. Thus, not unlike a psychiatrist, who often learns more about a patient's 'interiors' by observing the body language than by direct interrogation, a biochemist, studying the 'body language' of a cell, may extract information about delicate 'cell interior processes' that would be perturbed by more direct experimental approaches.

Animals↗
PubMed1990

Production of recombinant human interleukin-2 with BHK cells in a hollow fibre and a stirred tank reactor with protein-free medium.

For the production of recombinant human interleukin-2 (IL-2) two different culture processes, a 1-2 liter homogeneous stirred bubble-free aerated system and a dense cell hollow fibre bioreactor were compared. Cultivations were carried out with serum- or protein-free medium formulations. In the stirred culture 0.75 mg IL-2 were produced with 1 l of perfused medium at a maximum cell number of 3 X 10(10). The product yield in the hollow fibre module was only 0.23 mg l-1 at a maximum cell number of 6 X 10(10). In contrast to results with hybridoma or EBV-transformed cell lines, in which hollow fibre bioreactors showed comparable efficiency to perfused stirred tank reactors, the tissue-like cell density is disadvantageous as adherent cells tend to stick together leaving insufficient intercellular space for removal of product.

Animals↗
PubMed1990

Mechanism of protection afforded by polyaspartic acid against gentamicin-induced phospholipidosis. II. Comparative in vitro and in vivo studies with poly-L-aspartic, poly-L-glutamic and poly-D-glutamic acids.

Poly-L-aspartic acid (poly-L-Asp) protects rats against gentamicin (GM)-induced nephrotoxicity (functional and pathological changes) and early cortical alterations (phospholipidosis and increase in cell turnover) without decreasing, but actually increasing, the renal accumulation of the drug. We suggested that this protection occurs through the complexation of GM by poly-L-Asp, after their pinocytosis and accumulation in the lysosomes of the renal cortex (Kishore et al., J. Pharmacol. Exp. Ther. 867-874, 1990). Here we examine further our proposal by comparatively assessing poly-L-Asp (as provided by the Sigma Chemical Co., St. Louis, MO; MW 9-11,000), with two other polyanionic peptides, viz, poly-L-glutamic (poly-L-Glu; MW 14,300) and poly-D-glutamic (poly-D-Glu; MW 20,000) acids obtained from the same supplier. In vitro, all three polyanions showed a similar capacity to bind GM, to displace it from anionic phospholipids at acid pH and thereby to decrease the inhibitory potency of GM toward lysosomal phospholipase A1. In vivo, however, only poly-L-Asp and poly-D-Glu were able to prevent the development of GM-induced renal lysosomal phospholipidosis as assessed by key biochemical criteria (increase in lipid phosphorus and decrease of acid sphingomyelinase activity) and by examination of the lysosomal content in the electron microscope (accumulation of myeloid bodies). Based on these criteria, poly-L-Glu completely failed to protect. In vitro, poly-L-Glu was 13- to 17-fold more susceptible to hydrolysis by liver lysosomal extracts at pH 5.4 after 48 hr incubation, as compared to poly-L-Asp and poly-D-Glu, respectively. Assuming that all three polyanions tested are transported and accumulated in lysosomes of renal cortex to the same extent and that their respective rates of hydrolysis therein compare to that measured in vitro, these results suggest that stability of polyanions in lysosomes is an essential requisite for protection against GM-induced phospholipidosis and thus strengthens our earlier proposal that the site of action of poly-L-Asp must be in lysosomes. Although protecting from phospholipidosis, poly-D-Glu, however, caused a so far undescribed lysosomal storage disorder consisting of the accumulation of osmiophilic, nonlamellar material. This study, therefore, also demonstrates that not all polyanions resistant to lysosomal enzymes can be used as nephroprotectants, inasmuch as these, as is the case for poly-D-Glu, may cause renal alterations on their own.

Animals↗
PubMed1979

Phase transition characteristics of diphosphatidyl-glycerol (cardiolipin) and stereoisomeric phosphatidyldiacylglycerol bilayers. Mono- and divalent metal ion effects.

Synthesis and phase transition chaaracteristics of aqueous dispersions of the homologous (12 : 0, 14 : 0, 16 : 0) diphosphatidylglycerols (cardiolipins) and phosphatidyldiacylglycerols are reported. Electron microscopy of the negatively stained aqueous dispersions reveals a characteristic lamellar structure suggesting that these phospholipid molecules are organized as bilayers in the aqueous dispersions. The phase transition temperature (Tm) and the enthalpy of transition (delta H) increase monotonically with chain length in the cardiolipin and phosphatidyldiacylglycerol series; Tm for phosphatidyldiacylglycerol is higher than that for cardiolipin of the same chain-length. The transition temperatures for the enantiomeric sn-3,3- and sn-1,1-phosphatidyldiacylglycerol and for the diastereomeric, meso-sn-1,3-phosphatidyldiacylglycerol are approximately the same. The molar enthalpy for the transition of cardiolipin-NH+4 bilayers is approximately twice the value for the phosphatidylcholines of the same chain length, i.e., the molar enthalpy per acyl chain is approximately the same in the two systems. The transition temperatures for metal ion salts of C16-cardiolipin exhibit a biphasic dependence upon the unhydrated ionic radii, i.e., the highest Tm is observed for Ca2+-cardiolipin and decreases for the salts of ions with smaller and larger ionic radii than that of Ca2+. The lowest Tm is observed for Rb+-cardiolipin. Monovalent metal salts of cardiolipin exhibit two phase transitions. This effect may result from different conformational packing of the four acyl chains due to differences in metal-phosphate binding.

Cardiolipins↗
PubMed1979

A ribonuclease-resistant region of 5S RNA and its relation to the RNA binding sites of proteins L18 and L25.

An RNA fragment, constituting three subfragments of nucleotide sequences 1-11, 69-87 and 89-120, is the most ribonuclease-resistant part of the native 5S RNA of Escherichia coli, at 0 degrees C. A smaller fragment of nucleotide sequence 69-87 and 90-110 is ribonuclease-resistant at 25 degrees. Degradation of the L25-5S RNA complex with ribonuclease A or T2 yielded RNA fragments similar to those of the free 5S RNA at 0 degrees C and 25 degrees C; moreover L25 remained strongly bound to both RNA fragments and also produced some opening of the RNA structure in at least two positions. Protein L18 initially protected most of the 5S RNA against ribonuclease digestion, at 0 degrees C, but was then gradually released prior to the formation of the larger RNA fragment. It cannot be concluded, therefore, as it was earlier (Gray et al., 1973), that this RNA fragment contains the primary binding site of L18.

Base Sequence↗
PubMed1979

The mechanism of epithelial shedding after ischemic damage to the small intestinal mucosa. A light and electron microscopic investigation.

The intestinal mucosa of the rat was examined by light and electron microscopy 15, 30, 60 and 120 min after complete ligation of the vessel arcades of the proximal jejunum. The characteristic sign of ischemic damage to the small intestinal mucosa and the reason for epithelial shedding is the appearance of membrane enclosed cytoplasmic blebs which arise at the cell base of the enterocytes and detach the epithelium from the basement membrane. This process begins at the tip of the villi before the enterocytes display signs of irreversible damage and progress to the base of the villi with continuation of the ischemia.

Animals↗
PubMed1979

Selenium requirement for active xanthine dehydrogenase from Clostridium acidiurici and Clostridium cylindrosporum.

The xanthine dehydrogenase of Clostridium acidiurici and C. cylindrosporum was assayed with methyl viologen as acceptor. In C. acidiurici the basal activity level was about 0.3 mumol/min x mg of protein. Cells grown on uric acid in the presence of 10(-7) M selenite showed a 14-fold increase in xanthine dehydrogenase activity, which decreased with higher selenite concentrations (10(-5) M). The supplementation with 10(-7) M molybdate or tungstate was without effect. High concentrations of tungstate decreased the xanthine dehydrogenase if selenite was also present. In comparison, high concentrations of molybdate affected only a small decrease in activity level at the optimal concentration for selenite and relieved to some degree the inhibitory effect of 10(-5) M selenite. With hypoxanthine and xanthine as substrates for growth again only the addition of selenite was necessary to show a similar increase in xanthine dehydrogenase activity. C. acidiurici could be grown in a mineral medium. Both xanthine dehydrogenase and formate dehydrogenase exhibited the highest level of activity if selenite and tungstate were present in that medium. In C. cyclindrosporum the basal activity level of xanthine dehydrogenase was about 0.95 mumol/min x mg of protein. The addition of 10(-7) M selenite to the growth medium increased the activity level about 3-fold, but the highest level (3.7 U/mg) was reached if 10(-7) M molybdate was also added. The presence of tungstate resulted in a decreased enzyme activity.

Cell-Free System↗
PubMed1979

Carcinoma of the oral cavity: on the prognostic significance of the primary tumour site (by levels and areas).

The prognostic significance of primary tumour site in carcinomas of the oral cavity was investigated in a series of 585 cases. For the subsamples (levels and areas of oral cavity) studied, the numerical distribution of TNM categories, life tables and life table comparisons were computed. This produced the following results: Given an identical extension and analogous metastazising rate, there is no computationally demonstrable difference in prognosis between primary tumours sited at different levels and areas of the oral cavity. The exception are the T1Nx categories, for which a difference exists between precanine and retromolar sites. These results should be re-examined on the basis of a larger series.

Actuarial Analysis↗
PubMed1979

Chemical evidence for a codon-induced allosteric change in tRNALys involving the 7-methylguanosine residue 46.

[32P]TRNALys, from Escherichia coli, was modified with kethoxal, in the presence and absence of the oligonucleotide codon (A)4. The presence of the codon resulted in a faster modification rate of the tRNA at three guanine sites which were identified by a diagonal fingerprint method. A large increase in the modification rate occurred at the 7-methylguanosine residue 46 (m7G-46) in the presence of the codon: weakly enhanced modification was observed at G-15 and G-57. It is concluded that the formation of a codon-anticodon complex induces, primarily, a conformational change involving disruption of the m7G-46 from the m7G-46 . G-22 . C-13 base triple. Subsequently, the guanines of G-15 and G-57, in the D and T loops, respectively, become slightly more reactive, suggesting a weak tendency for these two interacting arms to unfold. The results are interpreted in terms of an equilibrium between two main conformers, and a third minor one; the possible significance of these conformers in protein biosynthesis, is considered.

Base Sequence↗
PubMed1979

[On the influence of thiocyanates on the delayed immune response in intact and epinephrectomised guinea pigs (author's transl)].

Daily application of 32 mg/kg sodium thiocynate from 1--11th respectively 12th--21st experimental day causes in epinephrectomised guinea pigs at the 26th experimental day an inhibition of cell-mediated immune response (sensitization was induced by intraperitoneal injection of horse serum at the 5th and 7th experimental day). The inhibition of cell-mediated immune response could be demonstrated by means of migration inhibition of spleen cells. Epinephrectomy was performed by operation procedures twice a week. Gluco- and mineralocorticoids were applied supplementary. -- Also other proved thiocyanates respectively compounds with thiocyanate groups such as potassium thiocyanate, ammonium thiocyanate and d,1-2-imino-3.4-dimethyl-5-phenyl-thiacolidinhydrothiocyanate showed the same effect. The results are only pointed out in intact animals, but distinct in epinephrectomised guinea pigs. Finally a significant weaker effect, but of the same kind was observed by potassium- and sodium iodate. Every used dose of prednisolone and cyclophosphamide suppress the migration inhibition. The influence of 2-iminothiacolidin-4-carbon acid and desoxycorticosteronacetat on the migration inhibition is different and depends on the antigen dose applied for sensitization. -- Simulated daily injections undertaken in form of stitches and application of aqua destillata are inefficacious.

Adrenal Glands↗
PubMed1979

Ultrasonic evaluation of the gallbladder in sickle cell disease.

The gallbladder is frequently diseased in sickle cell anemia. The distinction between cholecystitis and the abdominal crisis of sickle cell disease is difficult to make. Ultrasonography permits a rapid evaluation of the gallbladder in sickle cell disease.

Adult↗
PubMed1978

[Hormone dependent, functional gynecologic morphology in infancy and adolescence presented on the example of the cervix uteri].

Signs of different activities in the dynamic morphology of the epithelium and mucus of the cervix uteri are demonstrated in the female fetus, newborn, child and adolescent. Besides the morphological description of the ectropium, transitional zone, s.c. "reserve-cells", squamous cell nodes and production and secretion of mucus other investigations were done by allometry, caryometry and histochemistry. The examinations allow insight into the hormonal activities specially of the estrogenes in different periods of female life.

Adolescent↗