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Biomedical subjects

R Rudolph

Publications and source records attributed to R Rudolph.

At least 73 records · Page 4Linked to original sources
PubMed1994

Splenic interleukin 1 gene expression is associated with accumulation of macrophages and oxygen radical production in Plasmodium vinckei malaria.

High levels of interleukin 1 alpha (IL-1 alpha) were detected in vitro, in murine peritoneal macrophages stimulated with Plasmodium vinckei exogenous antigens, and in vivo, in sera of P. vinckei-parasitized mice. Moreover, high production of IL-1 alpha mRNA could be detected by in situ hybridization analysis in spleen sections of mice during the course of P. vinckei malaria. The observed IL-1 alpha gene expression in the spleen was associated with the accumulation of F4/80+ macrophages in the red pulp and in the marginal zone of follicles, as well as with the relative proportions of Mac-1+ cells in the spleen and the capacity of spleen cells to produce reactive oxygen intermediates during murine malaria.

Animals↗
PubMed1994

Biocompatibility of silver-coated polyurethane catheters and silver-coated Dacron material.

The local effects of silver-coated polyurethane catheters and Dacron material were compared to uncoated polyurethane catheters and Dacron material in a long-term implantation test using rabbits. The tissue-implant interaction was analysed by investigating the type and number of inflammatory cells, capillaries, fat tissue, the extent of fibrosis, thickness of the fibrous capsule, number and distribution of silver particles, and the size of giant cells. Silver-coated and uncoated materials displayed comparable signs of inflammation and tissue reaction.

Animals↗
PubMed1994

Increase of motion between lumbar vertebrae after excision of the capsule and cartilage of the facets. A cadaver study.

Seventeen fresh segments of cadaveric lumbar spines were tested in flexion, extension, and axial rotation. The resulting angular rotations were measured with the use of a goniometer and a three-dimensional system of video analysis. Measurements of flexibility were made, in order, in the intact spine; after decompression (bilateral total laminectomies, partial medial facetectomies, and foraminotomies); after excision of the capsule and cartilage of the facets; and after cancellous bone had been packed into the facet defects. Decompression resulted in a slight increase in the sagittal and axial ranges of motion. Subsequent excision of the capsule and cartilage of the facets, as in preparation for an arthrodesis of the facets, resulted in a significant increase in both the sagittal (5.7 +/- 2.9 degrees, mean and standard deviation) (p < 0.001) and the axial (1.4 +/- 0.9 degrees) (p < 0.01) ranges of motion compared with the motion in the intact specimen and with the motion in the specimen after only decompression had been done (p < 0.01 and p < 0.05, respectively). Packing of bone in the facets did not significantly reduce motion. It was calculated that the increase in the sagittal range of motion after excision of the capsule and cartilage of the facets would increase the tensile strain in a graft between the transverse processes of the fourth and fifth lumbar vertebrae (18 +/- 1 per cent tensile strain [mean and 95 per cent confidence interval] for the intact vertebrae and 25 +/- 1 per cent for the vertebrae in which the facets had been excised).

Biomechanical Phenomena↗
PubMed1994

Venlafaxine for treatment-resistant unipolar depression.

The purpose of this study is to evaluate the novel antidepressant venlafaxine for the management of treatment-resistant unipolar depression. We gave unblinded venlafaxine to 84 consecutive outpatients and inpatients who met DSM-III-R criteria for major depression and who had failed to respond to at least three adequate trials of antidepressants from at least two different antidepressant classes or electroconvulsive therapy, plus at least one attempt at augmentation. Patients were evaluated after a drug free period at baseline and regular intervals with the 21-item Hamilton Rating Scale for Depression (HAM-D-21), Montgomery-Asberg Depression Rating Scale (MADRS), and the Clinical Global Impressions Scale Improvement item (CGI). Full response for each scale was defined as follows: HAM-D-21 score of 8 or lower, a MADRS score of 12 or lower, and CGI score of 1; partial responses was defined as a 50% decrease in the HAM-D and MADRS, with final scores greater than 8 and 12, respectively, and for the CGI, a score equal to 2. About a third of patients were considered to be either full or partial responders (32.9% by HAM-D-21, 30.0% by MADRS, and 40% by CGI) after 12 weeks of venlafaxine treatment. To date, about 46% of responders have sustained their response for at least 3 months after the acute response. Venlafaxine is effective for a significant, but small, minority of patients with rigorously defined triple-resistant depression; the improvement was maintained for about half of the responders for the first 3 months of maintenance therapy.

Adult↗
PubMed1993

Recombinant soluble human interleukin-6 receptor. Expression in Escherichia coli, renaturation and purification.

The recombinant soluble human interleukin-6 receptor (srhIL-6R) was expressed in Escherichia coli as a non-glycosylated protein comprising the first 339 amino acids after the signal peptide. The protein accumulated within the cells as insoluble protein aggregates (inclusion bodies). After solubilization, 10% of the denatured srhIL-6R could be renaturated by an in vitro folding procedure using L-arginine and the glutathione-redox system. The native receptors were purified to near homogeneity by affinity chromatography on an IL-6-Sepharose column. The functional features of the recombinant soluble receptor were further analysed. A part of the extracellular domain (amino acids 145-345) of the human interleukin-6 receptor (IL-6R) was expressed in E. coli and the purified protein was used to raise antibodies in rabbits. Characterization of the antiserum obtained indicated that an epitope of 13 amino acids close to the transmembrane region is needed for recognition by the antibodies. Since the antiserum obtained did not interfere with IL-6 binding, it could be used to establish a cell-free IL-6-binding assay, In this assay, the srhIL-6R bound IL-6 with an affinity of Kd = 1.5 nM as measured by Scatchard-plot analysis. When 125I-IL-6 was chemically cross-linked to the purified srhIL-6R and analyzed by SDS/PAGE, several 125I-IL-6-containing bands were detected, indicating the possible existence of a multimeric structure of the natural IL-6/IL-6R complex. The srhIL-6R was shown to exhibit biological activity, i.e. it stimulated acute-phase protein synthesis in the recently established human hepatoma cell line HepG2-IL-6 which does not express the IL-6-binding subunit of the IL-6R complex on the cell surface.

Antibodies↗
PubMed1993

Prolyl isomerases catalyze antibody folding in vitro.

Some slow-folding phases in the in vitro refolding of proteins originate from the isomerization of prolyl-peptide bonds, which can be accelerated by a class of enzymes called prolyl isomerases (PPIs). We used the in vitro folding of an antibody Fab fragment as a model system to study the effect of PPI on a folding reaction that is only partially reversible. We show here that members of both subclasses of PPIs, cyclophilin and FK 506 binding protein (FKBP), accelerate the refolding process and increase the yield of correctly folded molecules. An acceleration of folding was not observed in the presence of the specific inhibitor cyclosporin A, but still the yield of correctly folded molecules was increased. Bovine serum albumin (BSA) increased the yield comparable to cyclophilin but, in contrast, did not influence the rate of reactivation. These effects were observed only when cyclophilin or BSA were present during the first few seconds of refolding. However, the rate-limiting reactivation reaction is still accelerated when PPI is added several minutes after starting refolding. In contrast, the prokaryotic chaperone GroEL influences the refolding yield when added several minutes after initiating refolding. The results show that PPIs influence the folding of Fab in two different ways. (1) They act as true catalysts of protein folding by accelerating the rate-limiting isomerization of Xaa-Pro peptide bonds. Proline isomerization is obviously a late folding step and has no influence on the formation of aggregates within the first seconds of the refolding reaction.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Isomerases↗
PubMed1993

Stabilization of creatinase from Pseudomonas putida by random mutagenesis.

Creatinase (creatine amidinohydrolase, EC 3.5.3.3) from Pseudomonas putida is a homodimer of 45 kDa subunit molecular mass, the three-dimensional structure of which is known at 1.9 A resolution. Three point mutants, A109V, V355M, and V182I, as well as one double mutant combining A109V and V355M, and the triple mutant with all three replacements, were compared with wild-type creatinase regarding their physical and enzymological properties. High-resolution crystal data for wild-type creatinase and the first two mutants suggest isomorphism at least for these three proteins (R. Huber, pers. comm.). Physicochemical measurements confirm this prediction, showing that the mutations have no effect either on the quaternary structure and gross conformation or the catalytic properties as compared to wild-type creatinase. The replacement of V182 (at the solvent-exposed end of the first helix of the C-terminal domain) does not cause significant differences in comparison with the wild-type enzyme. The other point mutations stabilize the first step in the biphasic denaturation transition without affecting the second one. In sum, the enhanced stability seems to reflect slight improvements in the local packing without creating new well-defined bonds. The increase in hydrophobicity generated by the introduction of additional methyl groups (A109V, V182I) must be compensated by minor readjustments of the global structure. Secondary or quaternary interactions are not affected. In going from single to double and triple mutants, to a first approximation, the increments of stabilization are additive.

Cloning, Molecular↗
PubMed1993

Personality characteristics and serum IgE level in patients with atopic dermatitis.

On the basis of clinical observations it was predicted that patients with atopic dermatitis (AD) differ from patients with chronic obstructive bronchitis (OB) in three personality variables; excitability (EX), inadequate stress coping (CO), and paranoidity (PA). Sixty-one patients with AD and 15 with OB were assessed using standard scales. Systematic comparisons between groups strongly confirmed these hypotheses. It was further assumed that AD patients with clinically relevant serum IgE levels (IgE > 100 IU/ml) score significantly higher on EX and CO than those with normal serum IgE levels (IgE < 100 IU/ml). In contrast, no significant differences between these subgroups were expected regarding paranoidity (which may be a consequence of the AD patients' cosmetic problems). These assumptions again were supported by the findings of the present study. The results underline the potential importance of assessing personality variables and serum IgE levels in the diagnosis of AD patients.

Adaptation, Psychological↗
PubMed1993

Familial multiple glomangiomas.

A 17-year-old patient had painful multiple glomangiomas, with an exceptionally strong family history extending back five generations. The mode of genetic transmission appeared to be autosomal dominant with complete gene penetrance. Simple excision provided symptom relief.

Adolescent↗
PubMed1993

Immunohistochemistry of fibronectin and actin in ungrafted wounds and wounds covered with full- and split-thickness skin grafts.

Fibronectin and actin content were measured with immunochemistry in excised wounds in 18 rats. In six rats, wounds were allowed to granulate and contract. Wounds were grafted with full-thickness skin in six rats and with split-thickness skin grafts in the remaining six. Multiple biopsies were taken for immunochemistry and electron microscopy. Actin and fibronectin content was greatest in ungrafted wounds. This content was reduced in wounds by skin grafting, with full-thickness grafts having a generally more inhibitory effect than split. In grafted wounds, actin was observed primarily in the wound bed, whereas fibronectin was present in both the wound bed and graft. Fibronectin appeared coincidently with actin in split-thickness skin grafts and their wounds. In contrast, full-thickness skin grafts had fibronectin staining before actin. The degree of wound contraction inhibition by different types of skin grafts appears to correlate with the fibronectin and actin staining patterns.

Actins↗
PubMed1993

Reconstruction after Mohs cancer excision.

At our institution, 363 skin defects following Mohs excision for carcinoma were repaired in a two-year period. The majority of the patients were women (62%). Most repairs were to the nose (42%), and almost all followed basal cell carcinoma excision (91% of tumor types). Flaps were preferable to skin grafts for facial repair, with forehead and nasolabial flaps particularly useful for the nose. Injection of Kenalog (triamcinolone acetonide, 5-20 mg/mL) speeds the maturation of scars and flaps.

Adult↗
PubMed1993

Seroprevalence of human immunodeficiency virus in admitted trauma patients at a southeastern metropolitan/rural trauma center.

Human Immunodeficiency Virus (HIV) seropositivity was prospectively evaluated for trauma patients admitted to Memorial Medical Center between September 1989 and August 1990. Epidemiologic data, HIV risk factors, and opportunity for body fluid exposure were compiled for 520 admitted trauma patients 15 years of age or older who met inclusion criteria. Serum samples were obtained from initial laboratory tests. Patient identifiers were removed, and matching blinded numbers were placed on patient serum and data forms. Centers for Disease Control laboratories tested for HIV with the enzyme-linked immunosorbent assay method. The Epi-Info (Version 5.01, 1990) software package was used for statistical analysis of epidemiologic data. Results showed HIV seropositivity of admitted trauma patients to be 0.96 per cent (5/520). HIV seroprevalence among young black males from our urban area who were injured during violent aggression was 3.5 per cent. Management of 80 per cent of patients resulted in opportunity for body fluid exposure. Illicit drug use was reported by 15 per cent; 7.5 per cent gave a history of transfusion since 1977; 3 per cent identified high risk sexual partners; three patients reported homosexual activity. Two patients denied risk factors, but were HIV-seropositive. The results indicate that HIV exposure is a potential hazard to health care workers and that HIV risk factors alone are not reliable in identifying the HIV-positive patient.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Secondary structure of human granulocyte colony-stimulating factor derived from NMR spectroscopy.

Recombinant 15N-, 13C-labeled human granulocyte colony-stimulating factor (rh-metG-CSF) has been studied by 2D and 3D NMR using uniformly labeled protein as well as residue-specific 15N-labeled samples. Assignment of the 1H, 15N backbone, and 60% 1H sidechain resonances has enabled the determination of the secondary structure of the protein. The secondary structure is dominated by alpha-helical regions with four stretches of helices between residues 11-41, 71-95, 102-124 and 144-170.

Amino Acid Sequence↗
PubMed1992

Binding of recombinant variants of human tissue-type plasminogen activator (t-PA) to human umbilical vein endothelial cells.

Endothelial cells synthesize and secrete hemostatic components like tissue-type plasminogen activator (t-PA) which is thought to be the major determinant of fibrinolytic activity in the blood. Most recently, a receptor protein for t-PA on human umbilical vein endothelial cells (HUVEC) in culture has been described (1); there are, however, in addition low affinity binding sites for t-PA on HUVEC. The sites of binding are of particular interest, because they are potential regulators of t-PA activity and clearance. We analysed the low affinity binding of recombinant t-PA (rt-PA) to normal diploid HUVEC and to the permanent human cell lines Jurkat, Daudi, HL 60 and K562 by flow cytometry applying t-PA specific monoclonal antibodies. Using this test system binding of both recombinant glycosylated human t-PA produced in Chinese hamster ovary cells (CHO-t-PA) and of nonglycosylated t-PA, produced in E. coli (BM 06.021) was investigated. Analysis of the binding pattern to HUVEC and other cell lines revealed that deglycosylation of full length rt-PA increases non-specific binding. Additionally, we investigated the binding properties of an unglycosylated t-PA deletion variant which comprises the kringle 2 and the protease domains (BM 06.022). Data obtained show that deletion of these domains most drastically reduces non-specific binding to HUVEC and other human cell lines.

Antibodies, Monoclonal↗
PubMed1992

[Clinical chemistry in leukosis of horses (review)].

Clinicopathological aspects of equine leukosis are discussed in a review. Among various other findings, only hypercalcaemia accompanied by paraneoplastic syndrome in the course of equine leukosis, increased values of alkaline phosphatase as usual in tumorous diseases, and hypalbuminaemia and hypergammaglobulinaemia in mesentric and intestinal forms of equine leukosis seem to have some diagnostic and pathogenetic significance. Changed values of further parameters are more or less non-specific concomitant signs, indicating that other organs or organ systems have been affected. However, in case of suspicion of equine leukosis furthermore clinicopathological investigations are recommended particularly for differential-diagnostic reasons.

Animals↗
PubMed1992

Interferon-gamma induced lethality in the late phase of Plasmodium vinckei malaria despite effective parasite clearance by chloroquine.

A combination therapy was tested consisting of chloroquine and interferon-gamma (IFN-gamma) in the late phase of blood-stage Plasmodium vinckei malaria in BALB/c mice. When mice were treated with three times 300 micrograms chloroquine at 24-h intervals starting at a parasitemia of 30%-50%, only 5 of 14 mice (36%) died 2-4 days after initiation of therapy. However, when infected mice received chloroquine plus 1 microgram IFN-gamma at the same time, 14 of 18 mice (78%) died 0.5-3 days after start of therapy (p < 0.05) despite clearance of parasitemia. The histopathology from mice dying after combination therapy revealed interstitial leukocyte infiltration of lung tissue, severe liver cell necrosis and kidney tubular necrosis. Pretreatment of P. vinckei-infected mice with pentoxifylline, a phosphodiesterase inhibitor, led to a significant decrease of IFN-gamma-induced lethality (p < 0.05). In contrast, pretreatment with neutralizing antibodies to tumor necrosis factor or with L-N-monomethyl arginine, the latter an inhibitor of the nitric oxide synthase, significantly increased lethality (p < 0.05).

Animals↗
PubMed1992

Reversible unfolding and refolding behavior of a monomeric aldolase from Staphylococcus aureus.

Thermal and GdmCl-induced unfolding transitions of aldolase from Staphylococcus aureus are reversible under a variety of solvent conditions. Analysis of the transitions reveals that no partially folded intermediates can be detected under equilibrium conditions. The stability of the enzyme is very low with a delta G0 value of -9 +/- 2 kJ/mol at 20 degrees C. The kinetics of unfolding and refolding of aldolase are complex and comprise at least one fast and two slow reactions. This complexity arises from prolyl isomerization reactions in the unfolded chain, which are kinetically coupled to the actual folding reaction. Comparison with model calculations shows that at least two prolyl peptide bonds give rise to the observed slow folding reactions of aldolase and that all of the involved bonds are presumably in the trans conformation in the native state. The rate constant of the actual folding reaction is fast with a relaxation time of about 15 s at the midpoint of the folding transition at 15 degrees C. The data presented on the folding and stability of aldolase are comparable to the properties of much smaller proteins. This might be connected with the simple and highly repetitive tertiary structure pattern of the enzyme, which belongs to the group of alpha/beta barrel proteins.

Enzyme Reactivators↗