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Biomedical subjects

M Hofer

Publications and source records attributed to M Hofer.

At least 55 records · Page 3Linked to original sources
PubMed2001

Combination of drugs elevating extracellular adenosine with granulocyte colony-stimulating factor promotes granulopoietic recovery in the murine bone marrow after 5-fluorouracil treatment.

Combined administration of drugs elevating extracellular adenosine, namely dipyridamole and adenosine monophosphate, together with granulocyte colony-stimulating factor was shown to enhance granulopoietic recovery in the bone marrow of mice treated with 5-fluorouracil. Enhanced regeneration was found both at the level of hematopoietic progenitor cells for granulocytes and macrophages and in the compartment of morphologically recognizable granulocyte precursors. The results might have positive clinical impact. The adjunct use of drugs elevating extracellular adenosine might reduce the cost expenditure of therapy with granulocyte colony-stimulating factor.

Adenosine↗
PubMed2000

Clinical variability and genetic homogeneity of the camptodactyly-arthropathy-coxa vara-pericarditis syndrome.

The camptodactyly-arthropathy-coxa vara-pericarditis syndrome (CACP) is an autosomal recessive condition characterized by the association of congenital or early onset camptodactyly and noninflammatory arthropathy with synovial hyperplasia. Progressive coxa vara deformity and/or noninflammatory pericardial or pleural effusions have been observed in some patients. Recently, the disease gene has been assigned to human chromosome region 1q25-q31, and truncating mutations have been identified in the megakaryocyte stimulating factor gene. Studying 12 patients from 8 unrelated families, we emphasized hip and spine involvement, particularly in the course of the disease as shown in a 58-year-old patient. Despite clinical variability, linkage studies support genetic homogeneity of the disease.

Adolescent↗
PubMed2000

[Innovative course concept for small group teaching in clinical methods. Results of a longitudinal, 2-cohort study in the setting of the medical didactic pilot project in Dusseldorf].

BACKGROUND AND OBJECTIVE: Medical students in Germany often criticize the anonymous and not practice-orientated way they are taught. It was the aim of this study to develop, try out and evaluate cost-effectiveness of practice-oriented interdisciplinary teaching in small groups. PATIENTS AND METHODS: The study was based on ca. 300 medical students/year, a practicable number in relation the average annual total intake by German medical schools. Between 1995 and 1998, 300 medical students annually, chosen by lot, were offered voluntary additional teaching of imaging methods (computed tomography, endoscopy and sonography), from a total of 2485 students (1276 females, 1209 males; mean age 25.8 years), the reminder serving as controls. After lecture-demonstration to all, the selected small groups were separately taught. They performed sonography on each other in small cohorts of 5 or they practised endoscopies on phantom models under supervision of a student tutor. In addition, lecturers circulated among the groups to answer additional questions and provide further help. All participants evaluated the course concept and the instructors on a questionnaire provided by the interdisciplinary centre for tertiary education. The effects of teaching on the participants were tested by a practical test in the form of an objective structured clinical examination (OSCE). RESULTS: Ca. 80% of course participants reached the intended aim and passed the OSCE examination. They gave the instructions in the pilot project highest marks, in all its criteria nearly one mark higher than those of other evaluated teaching sessions. Pre-clinical students judged the programme even more favourably than those in their clinical years. The additional cost incurred was moderately low at ca. DM 67 per year per student. CONCLUSION: Modern practice-oriented small group teaching will provide high quality results even with large numbers of students. The concept has already been taken over by other medical faculties.

Adult↗
PubMed2000

Positive effects of dialyzable leukocyte extract (DLE) on recovery of mouse haemopoiesis suppressed by ionizing radiation and on proliferation of haemopoietic progenitor cells in vitro.

Dialyzed leukocyte extract (DLE) (Immodin SEVAC, Czech Republic) was shown to enhance the recovery of the pools of hemopoietic stem cells (CFUs) and of granulocyte-macrophage hemopoietic progenitor cells (GM-CFC) in the bone marrow in vivo, as well as to increase the numbers of leukocytes and thrombocytes in the peripheral blood of mice exposed to a sublethal dose of gamma-rays, with an ensuing increase in the numbers of mice surviving the lethal radiation dose. In experiments performed in vitro, DLE or sera of mice administered with DLE were added to cultures of intact mouse bone marrow cells containing suboptimal concentrations of hemopoietic stimulatory cytokines, namely recombinant mouse interleukin-3 (rmIL-3) or recombinant mouse granulocyte-macrophage colony-stimulating factor (rmGM-CSF); under these experimental conditions, both DLE and sera of mice administered DLE were found to increase the counts of GM-CFC colonies in the cultures. It can be hypothesized on the basis of the findings obtained in vitro that the described co-stimulating activity (CoSA) of DLE may play a role also under in vivo conditions; the enhancement of the recovery of hemopoiesis suppressed by ionizing radiation may be due to a co-operation of the stimulatory effects of DLE with the action of cytokines endogenously produced in irradiated tissues.

Animals↗
PubMed2000

Adamantylamide dipeptide stimulates hematopoiesis and increases survival in irradiated mice.

It has been demonstrated that the synthetic immunostimulatory compound, adamantylamide dipeptide (AdDP) produces hematopoiesis-stimulating effects in mice exposed to sublethal doses of ionizing radiation and increases survival in experimental animals irradiated with a lethal dose. These findings might suggest contingent extension of clinical indications for the administration of AdDP for the conditions of hematopoietic suppression, especially in oncology.

Adjuvants, Immunologic↗
PubMed2000

Influence of the joint treatment with granulocyte colony-stimulating factor and drugs elevating extracellular adenosine on erythropoietic recovery following 5-fluorouracil-induced haematotoxicity in mice.

The presented data address the problem of pleiotropic effects of granulocyte colony-stimulating factor (G-CSF) and suggest the ability of drugs increasing the level of extracellular adenosine to activate erythropoiesis when given jointly with G-CSF. To demonstrate these interactions, the effects of the drugs on the recovery from erythropoietic damage induced in mice by a single dose of 5-fluorouracil (5-FU) were investigated. Elevation of extracellular adenosine and thus activation of adenosine receptors was induced by joint administration of dipyridamole (DP), a drug inhibiting the cellular uptake of adenosine, and adenosine monophosphate (AMP), an adenosine prodrug. The drugs were injected in a 4-d treatment regimen starting 2 h after 5-FU injection. Both DP+AMP and G-CSF alone induced only weak effects. However, the combination of the three drugs produced significant elevation of erythrocytes in the peripheral blood which pertained in the posttreatment period. Stimulation of proliferation of erythroid progenitor cells (BFU-E) in femoral bone marrow and increased levels of reticulocytes in the peripheral blood were observed in the course of the 4-d treatment regimen. In addition, significantly decreased mean cell haemoglobin accompanying the elevated numbers of erythrocytes in the combination-treated mice was found. This effect could be interpreted as the result of a sublethal 5-FU-induced damage to erythroid progenitor and precursor cells forced to proliferate intensively by the combination therapy. The observed additivity and synergism of G-CSF with elevated extracellular adenosine in terms of erythropoiesis is an interesting finding with potential implications in clinical practice.

Adenosine↗
PubMed2000

Radioprotective action of extracellular adenosine on bone marrow cells in mice exposed to gamma rays as assayed by the micronucleus test.

The frequency of micronucleated polychromatic erythrocytes (PCEs) in mouse bone marrow was assessed after administration of dipyridamole and/or adenosine monophosphate (AMP) to nonirradiated mice or to mice irradiated 15 min later with a sublethal dose of 6.5 Gy gamma rays. In nonirradiated mice, the administration of the drugs increased the frequency of micronucleated PCEs significantly (by 108%). In contrast, in irradiated mice, the number of radiation-induced micronucleated PCEs was significantly decreased if the mice had been pretreated with dipyridamole or AMP alone (by 24% after administration of each of the compounds) and in particular after administration of the drugs in combination (by 36%).

Adenosine Monophosphate↗
PubMed1999

Mechanisms of coal solubilization by the deuteromycetes Trichoderma atroviride and Fusarium oxysporum

Three different mechanisms can be envisaged that are used by fungi to solubilize coal: the production of alkaline substances, the extrusion of chelators and, of special interest in the scope of biotechnology, the action of enzymes. Whether these mechanisms are operating separately or in various combinations has not yet been finally assessed. The two deuteromycetes Fusarium oxysporum and Trichoderma atroviride solubilize coal by synergistic effects of various differnt mechanisms depending on the cell metabolism. F. oxysporum seems to solubilize coal by increasing the pH of the mycelial surroundings and by the action of chelators induced during growth in glutamate-containing media (without involvement of enzymes). T. atroviride, on the other hand, appears to use, in addition to an alkaline pH and a high chelator activity, at least two classes of enzyme activity to attack coal: hydrolytic activity for coal solubilization and ligninolytic activity for degradation of humic acids.

Journal Article↗
PubMed1999

Anxiety, motor activation, and maternal-infant interactions in 5HT1B knockout mice.

This study describes the development of anxiety and motor activation in mice lacking the serotonin (5HT) 1B receptor and in wild type controls and characterizes their early mother-infant interactions. In the isolation-induced ultrasonic vocalization paradigm, 5HT1B knockout pups vocalized less and were hyperactive, rearing, jumping, and rolling more often than wild type pups. One week postpartum, 5HT1B knockout mothers spent 20% more of their time outside the nest and were also hyperactive, rearing and climbing to the edge of the cage more often than the wild type mothers. There were no genotype effects on pup retrieval. Knockout adults were less anxious in the elevated plus-maze, defecated less, and head-dipped more, although none of the standard measures of anxiety (time and entries in the open arms) were different. 5HT1B knockout mice of both sexes were hyperactive during both the light and the dark phases of the 24-hr cycle. Thus, 5HT1B knockout mice show reduced anxiety and are hyperactive throughout their life.

Animals↗
PubMed1999

Adult-onset Still's disease with persistent plaques.

Adult-onset Still's disease (AOSD) is a systemic disorder characterized by intermittent fever, evanescent rash, arthralgias or arthritis and predominantly neutrophilic leucocytosis. We report on a 16-year-old woman with Still's disease who developed, in addition to the typical rash, persistent papular lesions on her face, neck and upper and lower back. Although the presence of fixed skin lesions is not a characteristic feature of AOSD, their appearance at the onset of the disease and their evolution suggest that they represent a specific manifestation of the disease.

Adolescent↗
PubMed1999

Borna disease virus in human brains with a rare form of hippocampal degeneration but not in brains of patients with common neuropsychiatric disorders.

To estimate the frequency of persistent Borna disease virus (BDV) infections of the human central nervous system and to determine which neuropsychiatric disorders might be associated with this viral infection, reverse transcription-nested polymerase chain reaction was used to screen a large collection of autopsy brain samples for the presence of BDV-specific nucleic acids. The presence of BDV RNA was found in 3 brains of persons with psychiatric symptoms and prominent hippocampal degeneration previously reported to be positive by others. However, no BDV RNA was detected in 86 randomly collected brains from persons with various psychiatric disorders, including schizophrenia, affective disorders, and Alzheimer's disease, or from suicide victims or in 52 brains from healthy controls. Furthermore, no BDV-RNA was detected in 16 surgical brain samples from persons with epilepsy-associated hippocampal sclerosis. These results indicate that life-long persistent BDV infections are rare in humans and that such infections may be associated with certain forms of hippocampal degeneration.

Adult↗
PubMed1999

Effects of in vivo administration of adamantylamide dipeptide on bone marrow granulocyte-macrophage hemopoietic progenitor cells (GM-CFC) and on ability of serum of the treated mice to stimulate GM-CFC colony formation in vitro: comparison with muramyl dipeptide and glucan.

Adamantylamide dipeptide (AdDP), muramyl dipeptide (MDP), and glucan were shown to increase significantly the numbers of granulocyte-macrophage hemopoietic progenitor cells (GM-CFC) in the bone marrow of mice. However, whereas the sera of mice given MDP or glucan were found to stimulate the growth of colonies from GM-CFC in vitro, i.e. to produce a colony-stimulating activity (CSA), administration of AdDP did not lead to this effect. Nevertheless, when serum of mice given AdDP was added to the cultures concomitantly with a suboptimal concentration of mouse interleukin-3 (mIL-3), a broad spectrum hemopoietic stimulator, counts of colonies from GM-CFC were significantly increased, and accelerated growth of the colonies was found as well. This property of AdDP, i.e. its ability to exhibit co-stimulating activity (CoSA) without being able to exhibit CSA, suggests that AdDP acts in hemopoietic tissues differently as compared with the two other immunomodulators studied. It can be hypothesized that the action of AdDP is more specific when compared with its natural related compound, MDP, as well as with glucan. Our findings prove the possibility to stimulate by AdDP the granulopoietic compartment of hemopoiesis and are in agreement with previous observations concerning the absence of systemic side effects of AdDP. Both these qualities of AdDP may be advantageous when pondering over contingent clinical utilization of AdDP as hemopoietic stimulator.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1999

Pretreatment with granulocyte colony-stimulating factor reduces myelopoiesis in irradiated mice.

The purpose of this study was to investigate effects of the treatment prior to irradiation with granulocyte colony-stimulating factor (G-CSF) on hematopoiesis in B10CBAF1 mice exposed to a sublethal dose of 6.5 Gy of 60Co gamma radiation. G-CSF was administered in a 4-day regimen (3 microg/day); irradiation followed 3 h after the last injection of G-CSF. Such a treatment was found to stimulate granulopoiesis, as shown by increased counts of granulocyte-macrophage progenitor cells (GM-CFC) and of granulocytic cells in the femoral marrow and spleen at the time of irradiation. However, postirradiation counts of GM-CFC and granulocytic cells in the marrow of mice pretreated with G-CSF were reduced up to day 18 after irradiation. Interestingly, the D0 values for marrow GM-CFC determined 1 h after in vivo irradiation were 1.98 Gy for controls and 2.47 Gy for mice pretreated with G-CSF, indicating a decreased radiosensitivity of these cells after drug treatment. The inhibitory effects of the pretreatment with G-CSF on the postirradiation granulopoiesis could be attributed to the phenomenon of "rebound quiescence" which can occur after cessation of the treatment with growth factors. Postirradiation recovery of erythropoiesis in the spleen of mice pretreated with G-CSF exhibited a dramatic increase and compensated for the decreased erythropoiesis in the marrow at the time of irradiation. This complexity of the hematopoietic response should be taken into account when administering G-CSF in preirradiation regimens.

Animals↗