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Biomedical subjects

B Gruber

Publications and source records attributed to B Gruber.

70 records · Page 4Linked to original sources
PubMed1983

Dynamics of the cytoskeleton in Amoeba proteus. I. Redistribution of microinjected fluorescein-labeled actin during locomotion, immobilization and phagocytosis.

Fluorescein-labeled muscle actin was microinjected into Amoeba proteus and followed during intracellular redistribution by means of the image-intensification technique. The fully polymerization-competent protein becomes part of the endogenous actomyosin system undergoing dynamic changes over time periods of several hours. Single-frame analysis of long-term sequences enabled the direct demonstration of both the contractile activities and morphological transformations of microfilaments in normally locomoting, immobilized and phagocytozing specimens. In normally locomoting cells the filament layer undergoes continuous changes in spatial distribution depending on the actual pattern of cytoplasmic streaming and cell shape. The highest degree of differentiation is always maintained in the intermediate region between the front and the uroid, thus indicating this segment of the cortex to be the most important site in generating motive force for pseudopodium formation and ameboid movement. In immobilized cells contracted by the application of ruthenium red or relaxed by different anesthetics, the filament layer forms a continuous thick sheath beneath the cell surface or becomes completely disintegrated. In phagocytozing cells the local polymerization of actin at the tip of pseudopodia forming the food-cup and around the nascent phagosome points to a significant participation of the actomyosin system in the process of capturing and constricting prey organisms. Although our results provide clear evidence for the overall importance of motive force generation according to the hydraulic pressure theory, some motile phenomena exist in Amoeba proteus that cannot exclusively be explained by this mechanism.

Actins↗
PubMed1982

Specific cytosol binding of diethylstilbestrol in rat skeletal muscle.

Rat skeletal muscle cytosol proteins bound 3H-diethylstilbestrol (3H-DES). More than 90% of this binding was high capacity and low affinity. Serum albumin accounted for roughly 50-60% of the binding, as evidenced by its precipitation with anti-rat albumin IgG. About half of the binding was distinguishable from albumin and other serum proteins by its precipitation in 40% saturated ammonium sulfate. This material sedimented at 4-5S in high-salt sucrose gradients, and resolved into two components (8S and 4-5S) in low-salt. Following incubation at 23-27 degree C for one hour, 2% of the bound 3H-DES in whole cytosol (approximately 2 fmole/Mg cytosol protein) was retained by DNA cellulose, and was eluted with 0.6 M KCl. This small fraction of the total binding was inhibited by estrogens and DES analogues: estradiol-17 beta, DES, dienestrol, and hexestrol were strong inhibitors; isodienestrol, dimethylstilbestrol, estradiol-17 alpha, estrone, tamoxifen, MER-25, CI-628, and nafoxidine were weak inhibitors; dihydrotestosterone, testosterone, and prednisone did not compete. These observations indicate that specific estrogen-binding sites exist in rat skeletal muscle.

Ammonium Sulfate↗
PubMed1981

Localization of 3H-diethylstilbestrol in skeletal muscle.

The localization of diethylstilbestrol (DES) in skeletal muscle was studied in CF1 mice and perfused rat hindlimbs. There was a slow accumulation of 3H-DES in mouse muscle from 4 to 24 hours following i.p. injection even though plasma DES was decreasing. Twenty-four hours after injection of 50 microCi 3H-DES (714 pmole) mouse gastrocnemius contained 8.9 x 10(-17) mole unaltered 3H-DES per mg muscle. Extrapolating to the entire skeletal muscle mass of the animal, this represents 0.15% of the radioactivity injected. The radioactivity in muscle was completely extracted with 95% ethanol or ether: ethanol (3:1), and both unaltered DES and DES-metabolites were present in the extracts. The fraction of radioactivity due to unaltered DES 4 hours after injection was 0.51 +/- 0.09 in muscle and 0.30 +/- 0.11 in plasma. Significant extrahepatic metabolism of DES was demonstrated in perfused isolated rat hindlimbs by the presence of DES-metabolites in the perfusate. The radioactivity extracted from the perfused muscle itself was unaltered DES. These results indicate that skeletal muscle is an important site of DES localization in rodents.

Animals↗
PubMed1980

Ontogeny of the inflammatory response in the fetal rat.

Fetal rats of 16, 17 and 18 days gestation (dg) were injected with turpentine or Streptococcus faecalis in 1% India ink. Specimens of peritoneal tissues and exudates were collected at 24, 48 and 96 h after injection. Inflammation was present in some of the youngest animals (16 dg) 24 h after injection with bacteria. The response consisted of infiltrates of polymorphonuclear (PMN) and mononuclear (MN) cells in tissues adjacent to the peritoneum. Inflammatory cells were also found within the peritoneal cavity. Phagocytosis of ink particles and bacteria was noted in these cells and in cells of the serosa and adjacent mesenchyme. Free peritoneal cells were not seen in littermate controls. Phagocytosis was also noted in PMNs and MNs in the exudates collected at 48 h. A more marked granulocytic response was seen in animals sacrificed 24 h following bacteria-ink injection at 17 dg. Inflammation was more extensive and consistent by 19 dg. The reaction to turpentine was associated with the variable degree of tissue injury noted in histologic sections. The gestational age at time of injection was a more important determinant of the magnitude and character of response than was the duration of the lesion.

Animals↗
PubMed1979

Providing a less restrictive environment for profoundly retarded persons by teaching independent walking skills.

A basic right of all handicapped persons is to live in the least restrictive environment possible. In this investigation, procedures were evaluated for teaching four institutionalized males with profound retardation necessary skills to increase their individual freedom of movement. Following baseline, a travel training program with a backward chaining format was implemented to teach each person to walk independently from his living area to school. Travel training included instructions, practice, praise, feedback, verbal reprimands, prompts, and edible reinforcers. Each resident began walking the entire distance to school independently during training and also began walking back to the living area, although the latter set of skills was not specifically trained. Following termination of the formal investigation, follow-up measures of 1 to 8 weeks showed the residents continued going to school independently. A survey of residential facilities in 43 states provided social validation for the seriousness of the problems associated with transporting seriously retarded persons to school. Also, time efficiency measures indicated that training independent travel resulted in reductions of staff time required in school transportation. Results were discussed in light of the potential contributions of behavior analysis in providing less restrictive environments for seriously handicapped persons.

Adult↗
PubMed1977

Absence of clinical pneumonia following bronchoscopy with contaminated and clean bronchofiberscopes.

Two hundred forty-nine fiberoptic bronchoscopy procedures were surveyed for the presence of bronchoscopy-related pneumonia. The first 103 procedures were performed during a period when the fiberscope was presemably contaminated with Pseudomonas aeruginosa. Chart review of these 103 procedures and prospective epidemiologic surveillance of the remaining 146 procedures revealed no cases of bronchoscopy-related pneumonia.

Bronchi↗
PubMed1976

Deaths and complications associated with fiberoptic bronchoscopy.

A questionnaire was sent to 1,041 owners of fiberoptic bronchoscopes requesting data about complications of bronchoscopic examination; 323 (31 percent) of the questionnaires were returned. From approximately 48,000 procedures, ten deaths were reported and are described. Information about two additional deaths not obtained from data on the questionnaires is also included. All patients who died had either myocardial disease, severe chronic pulmonary disease, serious pneumonia, or cancer. Two deaths were associated with evidence on necropsy of fresh myocardial infarctions that had been unsuspected prior to the procedure. Two deaths occurred after administration of local anesthesia prior to bronchoscopic examination. Two were patients who previously had slowly hemorrhaging tumors that hemorrhaged massively following, respectively, forceps biopsy and saline lavage. Four brushes broke off in bronchi. Ten cardiac arrests and 41 life-threatening reactions to anesthesia also occurred.

Aged↗
PubMedDate not supplied

[Minimal metastatic and minimal residual disease in patients with Ewing tumors].

At least 95% of Ewing tumors (ET) are characterized by an EWS-gene rearrangement with either FLI-1 or ERG and by extraordinary high MIC2/CD99 expression. Both features can be used for the specific identification of tumor cells, which might also be present in blood and bone marrow in minimal metastatic or minimal residual disease. We report the establishment of sensitive ET cell detection methods based on these characteristics. Preliminary results of 14 patients are given and two cases are reported in detail. 6/14 patients showed RT-PCR positivity in the bone marrow whereas in 8/14 patients ET cells could be detected by immunofluorescence. Only in 2 patients, one at diagnosis and one at relapse, tumor cells were detected in blood samples by RT-PCR. Peripheral blood stem cells of 5 patients showed no contamination with ET cells. The versatility of the immunocytochemical approach as compared to the RT-PCR analysis is discussed in order to explain the discrepancies between the results obtained with the two detection methods.

Adolescent↗
PubMedDate not supplied

The study on adriamycin induced DNA scissions in human cells with different activity of some antioxidant enzymes.

Although the anthracycline antibiotic adriamycin has been widely used in treatment of variety of human malignances, the mechanism of its biological activity is still unknown. One of the proposed mechanisms of action assumes the generation of active oxygen species which may damage DNA of cells. In this study we investigated if the occurrence of DNA breaks induced by adriamycin depends on the intracellular level of antioxidant enzymes. The study was performed with two human cell lines (CRL2088 and CLV102) differing in activity of catalase and superoxide dismutase. The results indicated that the level of DNA breaks in both lines treated with adriamycin was similar despite of differences in the enzymes activity.

Antibiotics, Antineoplastic↗
PubMedDate not supplied

Prevalence of IgE rheumatoid factor (IgE RF) in mixed cryoglobulinemia and rheumatoid arthritis.

IgE RF was measured by ELISA assay using aggregated IgG as a solid phase immunosorbent and alkaline phosphatase-conjugated Fc epsilon-specific monoclonal and polyclonal antibodies as indicators. The presence of IgE RF was defined in this assay as binding of the conjugate greater than 2.33 SD above the mean for control sera (N = 27). Total IgE was elevated in 25% (13/52) of sera of patients with seropositive Rheumatoid Arthritis (RA), yet was normal in the sera of 17/19 Mixed Cryoglobulinemia (MC) patients. IgE RF was present in 33% (21/63; p less than 0.05) RA sera, and none of sera from 19 MC patients tested. It did not correlate with IgM RF titer or total IgE, and was not detected in separated IgM and IgG fractions of 7 purified mixed cryoglobulins from patients with MC. These findings suggest that IgE RF may not be an important pathogenic factor in the clinical manifestations of MC. Its potential significance in RA is discussed.

Arthritis, Rheumatoid↗
PubMedDate not supplied

The in vitro study on genotoxic activity of adriamycin and bleomycin in cells of mice with different catalase and superoxide dismutase activity.

Genotoxic activity of adriamycin and bleomycin in embryo cells from mice differing in anti-oxidant enzymes activity was investigated. The catalase activity in cultured in vitro embryo cells of C3H mice was 2.3-fold and superoxide dismutase 2.5-fold higher than of C57BL/10 mice. For genotoxicity evaluation, the micronucleus test in vitro was used. The results obtained indicated that the frequency of micronucleated cells in untreated C3H cultures was higher than in C57BL/10 cell cultures. The increase in micronuclei formation after treatment with adriamycin and bleomycin was higher in C57BL/10 than in C3H cells as compared with micronuclei in untreated cultures. The higher frequency of micronucleated cells in treated versus untreated C57BL/10 than C3H cell cultures may be caused by lower activity of anti-oxidant enzymes in C57BL/10 cells. It may suggest that DNA damage caused by adriamycin and bleomycin resulted from action of active oxygen species.

Animals↗