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Biomedical subjects

C Martens

Publications and source records attributed to C Martens.

35 records · Page 2Linked to original sources
PubMed1990

In vivo cytokine gene expression in T cell subsets of the autoimmune MRL/Mp-lpr/lpr mouse.

Expression of cytokine genes in freshly isolated T cell subsets in the autoimmune lpr mouse has been studied to determine what factors may be produced by these cells in vivo. RNA prepared from T cell subsets from diseased lpr mice and from the normal congenic strain, MRL/n, was tested for the presence of cytokine-specific message using the polymerase chain reaction. Cells of the expanded abnormal T cell subset were shown to express genes encoding interferon (IFN)-gamma, tumor necrosis factor (TNF)-beta, TNF-alpha and interleukin (IL)6, cytokines which are associated with inflammatory immune responses. These cells may thus play an important role in exacerbation of the pathological symptoms of the systemic autoimmune disease. These cells expressed no detectable IL1, IL2, IL3, IL4 or IL5. Phenotypically normal CD4+ and CD8+ T cells from both lpr and MRL/n also contained transcripts for IFN-gamma, TNF-alpha, TNF-beta and IL6. IL2 mRNA was found almost exclusively in the CD4+ subset, indicating that the CD8+ T cells in the lpr mouse are not highly activated through their class I major histocompatibility complex molecules to produce IL2, as could occur if a virus infection was inducing autoimmunity in these mice. Similar levels of IL2 mRNA were present in the CD4+ T cells of lpr and MRL/n mice, demonstrating that these cells are not defective in IL2 production in vivo.

Animals↗
PubMed1989

The abnormal T lymphocytes in lpr mice transcribe interferon-gamma and tumor necrosis factor-alpha genes spontaneously in vivo.

The autoimmune mouse strain MRL/MPJ/lpr/lpr is characterized by accumulation of an abnormal T cell population which does not express CD4 or CD8 surface antigens. These cells were thought to be immunologically inert based on their inability to proliferate in response to a variety of T cell mitogens. We investigated the capacity of these cells to express lymphokine genes using a sensitive RNase protection assay. RNA was isolated from abnormal T cells which were purified directly from diseased animals, either as CD4-/CD8- or as fluorescence-activated cell sorter-isolated B220+/Thy-1+ cells. These RNA preparations contained no detectable interleukin (IL) 2, IL 4, IL 5 or IL 6 transcripts, but did contain transcripts of genes for interferon-gamma and tumor necrosis factor-alpha. Thus, this expanded population of abnormal cells spontaneously expresses these two lymphokines which have many interacting effects on the immune system, and may have important roles in the pathogenesis of autoimmune disease in lpr mice.

Animals↗
PubMed1989

Expression of lymphokine genes in splenic lymphocytes of autoimmune mice.

Lymphocytes of autoimmune mice have been reported to have defective IL-2 production and proliferation in response to the mitogen concanavalin A. We have examined transcription of lymphokine genes in Con A stimulated spleen cells from both autoimmune and normal mice and found that IL-2, IL-4 and gamma-interferon (IFN gamma) were induced in all mice tested. Spleen cells were taken from young (pre-disease) or old (clinically active) MRL/lpr (lpr) and male BXSB autoimmune mice and from their normal counterparts (MRL/n, BXSB females, BALB/c and DBA/2) and stimulated with Con A. Con A induced production of IL-2, IL-4 and IFN gamma message and protein, and kinetics of induction did not vary significantly among the strains. However, in old lpr mice, levels of IL-2 protein and mRNA were about 10-fold lower than in other strains; IL-4 protein and mRNA were decreased approximately three-fold; and IFN gamma mRNA was readily detected in unstimulated cells and low but detectable levels of protein were produced constitutively. In contrast, little or no defect in IL-2 or IL-4 transcription or secretion were seen in male BXSB mice and no constitutive IFN gamma transcription was seen in this strain. These data indicate that all three lymphokine genes are activated by Con A in autoimmune mice, even though Con A-induced proliferation is defective in these mice. Furthermore, autoimmune mouse strains vary in terms of lymphokine expression: male BXSB mice display a normal lymphokine profile, whereas lpr mice show a marked imbalance of lymphokines compared to normal controls.

Animals↗
PubMed1985

Relationship among IgE-binding factors with various molecular weights.

The rat-mouse T cell hybridoma 23B6 forms IgE-binding factors on incubation with IgE. The hybridoma cells incubated with IgE contained intracellular IgE-binding factors of 60K, 30K, 14K, and 10K daltons, and secreted the 60K, 30K, and 14K IgE-binding factors. Both intracellular and extracellular IgE-binding factors of 60K and 14K daltons selectively suppressed the IgE response, whereas the 30K and 10K factors failed to do so. Reduction and alkylation of the extracellular 60K IgE-binding factors yielded fragments of 30K, 14K, and 10K daltons with IgE-binding activity, and the same treatment of the 30K "inactive" IgE-binding factor yielded the 14K and 10K fragments. Among the fragments obtained by reduction and alkylation, only the 14K IgE-binding factors selectively suppressed the IgE response. Monoclonal antibody OX 3, which recognizes an Ia determinant, bound the 60K and 30K IgE-binding factor, and the 30K fragment obtained by reduction and alkylation. None of the 14K and 10K IgE-binding factors and fragments of comparable size obtained by reduction and alkylation contained the antigenic determinant. The results indicate that 30K, 14K, and 10K IgE-binding factors are derived from the 60K precursor molecules. Transfection of COS 7 monkey kidney cells with a single cloned cDNA, 8.3, which encodes rodent IgE-binding factor, resulted in the formation of IgE-binding factors of 60K and 11K daltons. Both species of the factors had affinity for lentil lectin and selectively potentiated the IgE response, but only the 60K IgE-binding factor bound to the monoclonal anti-Ia antibody. Reduction and alkylation of the 60K IgE-binding factors from the cDNA clone yielded an 11K fragment having the same properties as the 11K IgE-binding factor, with respect to the affinity for lentil lectin, and the biologic activities. Because the cDNA clone was constructed from mRNA of 23B6 cells, it appears that the 60K IgE-binding factor molecule from 23B6 cells is composed of a single peptide chain, and that the naturally formed 30K, 14K, and 10K IgE-binding factors are formed by post-translational modification of the 60K peptide.

Animals↗
PubMed1979

[Clinical experience with Knappwost's galvanic pin element].

Having dealt with the manufacture, application and mode of action of the pin element, the authors report of clinical and radiological findings (after six and twelve months) which they compare with corresponding results from the literature and experience gained with the treatment of apical periodontitis with iodoform paste. The paper ends with recommendations for practice.

Calcium Hydroxide↗
PubMed1977

Effectiveness of extra-ovular injection of prostaglandin E2 in tylose gel to ripen the cervix prior to elective induction of labor at term.

Ripening of the unfavorable cervix (Bishop score less than or equal to 4) was obtained in 92 clinically normal gravidae at term (68 nulliparae and 24 parous women), not in labor and with intact membranes, by injecting one or two doses (250 to 500 mug each) of prostaglandin (PG)E2 suspended in a viscous gel (5% Tylose) into the extra-ovular space. On average 7 to 8 hours after the injection the mean increase of the cervical score was 3.7 and 4.1 in the nulliparous and parous women, respectively. Complications associated with placement of the catheter were few. The method is simple, well tolerated and no untoward maternal or perinatal effects could be directly attributed to it. However, suitable criteria for predicting both the effect of the procedure and the optimal PG dose to be administered are still needed.

Catheterization↗
PubMed1977

Droperidol in acutely agitated patients. A double-blind placebo-controlled study.

Forty-one acutely agitated patients received an i.v. injection of 4 ml of a double blind solution containing either 10 mg of droperidol or placebo. The need for further medication (5 mg of haloperidol after 3 minutes or individually adapted psychotropics after 30 minutes) was used as a parameter for the evaluation of the results. Three minutes after the injection, haloperidol was needed by only six out of 19 patients of the droperidol group, but by 19 patients of the control group. Thirty minutes after the first injection, further medication was needed by only four droperidol patients and 10 placebo patients. No side effects could be attributed to the double blind medication.

Acute Disease↗
PubMedDate not supplied

Aluminum induces neurite elongation and sprouting in cultured hippocampal neurons.

It has been reported that the aluminum content in the human brain increases with age, and it is particularly high in those with Alzheimer's disease. In this study, we found that a low aluminum concentration (100 mumol/L) in the culture media of opossum hippocampal neurons can induce extensive neurite outgrowth (ie, elongation and branching of neurites) and sprouting (ie, outgrowth of filiform processes from neurite varicosities) within 48 hours. Such changes in neurite morphology were remarkably similar to those described in the aged or Alzheimer's disease brain. Neurites that responded to aluminum varied greatly in length, thickness, and branching pattern. Many neurites appeared to have no clear directional growth pattern because they frequently changed their course and formed a meshwork of neurites with others originating from the same cell body. Sprouting neurites varied in length, thickness, and branching pattern, but they always originated from a globular enlargement of neurites along the neurite shaft or at the terminal end. Such growth pattern and extensive sprouting of neurites did not fit the growth pattern displayed by the control neurons. Our findings suggest that aluminum may be involved in the neuronal remodeling characteristic of aging and Alzheimer's disease.

Aluminum Compounds↗
PubMedDate not supplied

[Centronuclear myopathy (author's transl)].

Three cases of centronuclear myopathy are reported in a sibship. The disease starts during the late childhood and has a very slow progressive course. Clinical examination reveals a ptosis of the eyelids, a weakness of the facial muscles, a high-arched palate and a diffuse involvement of the lower extremities. The respiratory muscles are involved in the two oldest siblings. Combined morphological studies of the tibialis anterior muscle in one patient demonstrate the following features: 1. the presence of small type I fibres and of large type I or type II fibres; 2. a predominance of type I fibers which represent 86% of the total amount of muscle fibres; 3. central nuclei in about 98% of the muscle fibres; 4. moderate ultrastructural changes. All these features are compared with the relevant data of the literature.

Adenosine Triphosphatases↗
PubMedDate not supplied

The invasive pit-and-fissure sealing technique in pediatric dentistry: an SEM study of a preventive restoration.

From the dental literature, it is clear that the clinical application of pit-and-fissure sealants is a necessity in pedodontics. The choice between the non-invasive and the invasive techniques remains a matter of debate. In this SEM study, a comparison is made between different types of burs in order to obtain the best fissure preparation before the application of a sealant. The results of this study clearly show that, by applying the invasive sealing technique, the choice of an adequate bur is important to obtain a caries-free fissure, with a minimal loss of tooth substance. Two types of burs were found to perform best, according to the amount of tooth substance removed. Moreover, from a clinical point of view they were also found to be the most efficient ones. A detailed review is given concerning the choice of the actual preventive restorations for use in pedodontics.

Dental Bonding↗
PubMedDate not supplied

Hyaline bodies in skeletal muscle of a patient with a mild chronic nonprogressive congenital myopathy.

Subsarcolemmal hyaline bodies were found in a skeletal muscle biopsy of a 10-year-old boy manifesting mild non-evolutive motor disturbances with frequent falls since early childhood. The hyaline bodies occurred in type I fibers and stained intensely with the myosin ATP-ase reaction at pH 4.2. They immunostained intensely with polyclonal anti-skeletal myosin and monoclonal anti-skeletal fast myosin. Additionally, immunoreactive deposits to anti-desmin were observed at the border of some bodies. At the ultrastructural level, these bodies were not surrounded by a limiting membrane and were only localized in subsarcolemmal areas. They contained moderately dense and disorganized filaments which appeared to be in continuity with thick myosin filaments of intact adjacent myofibrils. They stained negatively for polysaccharides according to the periodic acid-thiosemicarbazide silver proteinate method of Thiéry (1967). Analogies and differences with reported cases in the literature with similar subsarcolemmal deposits and other ultrastructural findings in congenital myopathies are discussed.

Biopsy↗