Biomedical subjects

M Ernst

Publications and source records attributed to M Ernst.

At least 19 recordsLinked to original sources

PubMed1992

Cytokines involved in monocyte mediated tumor cell death and growth inhibition in serum-free medium.

In a serum-free culture system, the release of TNF, lI-1, lI-6, IFN-alpha, and IFN-beta during interaction of elutriated human monocytes (MO) with human tumor cells (TC) was studied by ELISA-technique. Contributions of these cytokines to inhibition of TC-growth and to induction of TC-death by supernatants (SU) gained from such MO/TC-interaction cultures were investigated using affinity chromatography for removal of individual cytokines. Although the TC used are relatively insensitive to recombinant human TNF, withdrawal of TNF causes 50% to 75% reduction of SU-induced TC-death rates, suggesting that susceptibility to TNF is raised during MO/TC-interaction by the other cytokines. Individual removal of other cytokines does not cause reduction of SU-mediated TC-death. However, combined withdrawal of lI-1 and IFN-alpha/beta causes in 2 of 4 TC-lines significant reduction of TC-death. Combined removal of TNF, IFN-alpha/beta, lI-1, and lI-6 leads to complete prevention of SU-mediated growth inhibitory and lytic effects, suggesting that besides these cytokines other signals are not involved significantly. SU-effects can be mimicked by appropriate combinations of authentic cytokines. The response of TC to SU- or cytokine-exposure is strikingly dependent on TC-density, leading at subconfluent TC-density exclusively to inhibition of growth and at postconfluent TC-density to induction of cell death. The principal effect of SU or cytokine combinations in this context seems to be the activation of growth inhibitory signal transduction pathways leading to TC-death in postconfluent TC-populations exclusively if growth stimulatory pathways are activated at the same time. Mouse L cells do not follow this reaction pattern: Their death is exclusively dependent on the presence of TNF in SU and they die upon SU-exposure at postconfluent as well as at subconfluent cell density.

Animals↗

PubMed1992

Cognitive abilities of patients with Lesch-Nyhan disease.

Parents of 42 patients with Lesch-Nyhan disease completed a questionnaire systematizing caregiver observations of the subject's behavior during a wide variety of daily events. Responses were grouped in nine categories reflecting different aspects of cognitive skills. Only 1 boy appears to have any significant generalized cognitive impairment. The patients' memory for both recent and past events is excellent, their emotional life has a normal range of reactions and is appropriate; they have good concentration, are capable of abstract reasoning, have good self-awareness, and are highly social. However, they are behind in academic ability, with only 15% at grade level for math and reading. Implications for designing educational activities, parenting or caregiver strategies, and research methodology are discussed.

Achievement↗

PubMed1992

Human monoclonal antibodies for the differentiation of Rh-D categories.

With the introduction of human monoclonal antibodies against antigens of the Rh-system it was possible to solve a series of problems, as, for instance, the permanent availability of reagents. Another problem, the classification of D-categories with a panel of specific monoclonal antibodies, also might be solved by the production of such antibodies. Especially the classification of Cat. VI-cells is of great importance. We present a panel of five human monoclonal antibodies useful for the definition of Rh-D categories. The antibodies are designated as BS221, BS227, BS228, BS230 and BS231. By positive or negative reactions with expected category cells it is possible to determine the corresponding category. All Cat. VI-cells of a defined panel could be identified. Of particular interest is the antibody BS221 due to its reactivity with Cat. VI-cells. The fact, however, that BS221 is missing the detection of some Cat. VI-cells indicates a further subdivision of Cat. VI.

Antibodies, Monoclonal↗

PubMed1992

Results of the DGTI workshop on the evaluation of the reactivity of monoclonal anti-D.

All D+ samples were detected by all monoclonal antibodies without problems. Very few of the 3000 D- samples showed a +/- to ++ reaction with some of the IgG type mabs using the Coombs technique. It is still open whether these are specific reactions with weak positive samples, which were negative with polyclonal sera. IgM type mabs detected up to 100% of the Du samples dependent on the Rh-phenotype and the technique used (CCDuee greater than CcDuee greater than ccDuEe). Most of the CCDuee samples reacted very strong and should no longer be regarded as Du.

Antibodies, Monoclonal↗

PubMed1992

Results of the DGTI workshop on the evaluation of the reactivity of monoclonal anti-D.

All D+ samples were detected by all monoclonal antibodies (mabs) without any problem. Very few of the 3,000 D- samples showed a +/- to ++ reaction with some of the IgG type mabs using the Coombs technique. It is still open whether these are specific reactions with weakly positive samples, which were negative with polyclonal sera. IgM type mabs detected up to 100% of the Du samples dependent on the Rh phenotype and the technique used (CCDuee > CcDuee > ccDuEe). Most of the CCDuee samples reacted very strongly and should no longer be regarded as Du.

Antibodies, Monoclonal↗

PubMed1992

Human monoclonal antibodies for the differentiation of RhD categories.

With the introduction of human monoclonal antibodies against antigens of the Rh system it was possible to solve a series of problems as, for instance, the permanent availability of reagents. Another problem, the classification of D categories with a panel of specific monoclonal antibodies, also might be solved by the production of such antibodies. Especially the classification of cat. VI cells is of great importance. Here we are presenting a panel of 5 human monoclonal antibodies useful for the definition of Rh-D categories. The antibodies are designated as BS221, BS227, BS228, BS230 and BS231. By positive or negative reactions with expected category cells it is possible to determine the corresponding category. All cat. VI cells of a defined panel could be identified. Of particular interest is the antibody BS221 due to its reactivity with cat. VI cells. The fact, however, that BS221 misses the detection of some cat. VI cells indicates a further subdivision of cat. VI.

Antibodies, Monoclonal↗

PubMed1992

Pimozide in autistic children.

This open pilot study explored the efficacy and safety of pimozide, over a 3-week period, in hospitalized autistic children. Eight males, ages 4.2 to 8.3 years, completed the study. Intellectual functioning ranged from moderate to profound mental retardation. Symptoms included severe withdrawal, stereotypies, hyperactivity and/or hypoactivity, aggressiveness, and temper tantrums. Therapeutic daily doses of pimozide ranged from 3.0 mg to 6.0 mg with a mean of 4.9 mg (0.12-0.32 mg/kg; mean, 0.22). Laboratory studies including electrocardiogram and liver function tests remained within normal limits. Untoward effects were minimal and transient. Decreases of behavioral symptoms were evidenced on all measures including the Children's Psychiatric Rating Scale, Clinical Global Impressions, and Global Clinical Judgments Scale (consensus rating). Of the 5 hypoactive children, 4 showed a decrease in hypoactivity, whereas 1 child showed worsening. These findings are promising and indicate the need for further study.

Autistic Disorder↗

PubMed1992

FcR+ and FcR- monocytes differentially secrete monokines during pokeweed mitogen-induced T-cell-monocyte interactions.

Monocyte subpopulations which differ in the expression of Fc receptor for human IgG (FcRI) differentially regulate the T-cell-dependent, pokeweed mitogen (PWM)-induced, polyclonal B-cell response. We, thus, studied the cytokine production in human peripheral blood monocyte and T-lymphocyte cultures activated with this lectin. Monocytes or their FcR+ and FcR- subpopulations stimulated with PWM were cultured with or without T lymphocytes or their CD4+ and CD8+ subsets. Both monocyte subpopulations cultured alone produced similar amounts of tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6), but FcR- monocytes showed significantly enhanced ability to secrete interleukin-1 (IL-1). T cells, especially CD4+, added to monocyte cultures enhanced IL-1 production. This enhancement was presumably due to interferon-gamma (IFN-gamma) release by T lymphocytes, since this lymphokine enhanced IL-1 secretion when added to PWM-stimulated cultures of monocytes. Addition of monocytes, in particular the FcR+ subpopulation, greatly enhanced production of IFN-gamma by T lymphocytes. Although both T-cell subsets produced IFN-gamma, the CD4+ cells were more efficient. These results indicate that in PWM-stimulated cultures subpopulations of monocytes differ in secretion of cytokines, which might explain their differential effect on T-cell-dependent immune responses in vitro.

Antigens, Differentiation↗

PubMed1992

Species-specific assessment of Mycobacterium leprae in skin biopsies by in situ hybridization and polymerase chain reaction.

Conventional histopathologic diagnosis of mycobacterial infections are limited to the determination of "acid-fast bacilli". A species-specific diagnosis is thus far impossible. In addition, routine microbiologic assessments of mycobacteria suffer from the major drawback that a species-specific diagnosis is extremely time-consuming and in several cases even impossible. As Mycobacterium leprae cannot be cultured in vitro, we tried to specifically target this obligate intracellular parasite by in situ hybridization and polymerase chain reaction (PCR) techniques. For this purpose we used a 22 mer oligonucleotide probe recognizing a species-specific sequence of the 16S rRNA of Mycobacterium leprae. Using an immunoenzymatic detection method for in situ hybridization we were able to specifically assess Mycobacterium leprae (a) in long-term cultured macrophages in vitro infected with different mycobacteria species and (b) in frozen sections of skin biopsies obtained from patients suffering from lepromatous leprosy. These results could be confirmed and extended by PCR experiments in which we used conserved oligonucleotide primers for 16S rRNA to amplify bacterial DNA isolated from different eubacterial species and from fresh-frozen as well as from formalin-fixed, paraffin-embedded and routinely processed mycobacteria-infected tissues. Upon Southern blot analysis, the Mycobacterium leprae-specific oligonucleotide probe exclusively hybridized with PCR products obtained from Mycobacterium leprae-containing samples (including paraffin sections), but not with PCR products obtained from samples containing other mycobacterial species. As species-specific oligonucleotide probes targeted at rRNA are described for a variety of mycobacterial species, these methods may be generally applied for a rapid species-specific assessment of mycobacteria in histologic material.

Base Sequence↗

PubMed1991

Augmentation of interleukin 2-activated cytotoxicity after treatment of cells with inhibitors of interferon production.

Low-density human lymphocytes cultured with recombinant interleukin 2 (rIL-2) generated a high level of interferon(s) (IFN). Consistently more IFN including IFN-tau was produced during the first 3 days of culture with rIL-2 than during the subsequent 4 days. That ability was mainly associated with mepacrine+ cells and was decreased by low concentrations of leucine methyl ester (Leu-O-Me) or ammonium chloride. Leu-O-Me was employed either for the pretreatment of cells before the culture or as the additive to culture medium. The decrease in IFN production after pretreatment was associated with enhanced rIL-2-activated cytotoxicity. Similarly, 1 mM of ammonium chloride or 1 mM of Leu-O-Me added to rIL-2 supplemented cultures for 3 days showed an association between inhibition of IFN-tau generation and increased activation of cytotoxic activity. Thus NK cells appear to regulate their own response to rIL-2 activation and the control mechanism seems to be associated with the ability of the cells to produce IFN(s) and possibly other cytokines.

Cells, Cultured↗

PubMed1991

Isolation of normal human follicular dendritic cells and CD4-independent in vitro infection by human immunodeficiency virus (HIV-1).

Immunohistological and electron microscopy studies of lymph nodes from patients infected with the human immunodeficiency virus 1 (HIV-1) demonstrated that follicular dendritic cells (FDC), the antigen-presenting cells of the B cell system, contain and may produce the virus. To elucidate the mode of infection of FDC with HIV-1 in vitro we developed an improved method for the preparation of single-cell suspensions of viable FDC with high purity (greater than 90% FDC). These isolated FDC were subjected to human T cell leukemia virus IIIB infection, which was monitored after 4 days in culture using the polymerase chain reaction. We were able to demonstrate that normal human FDC are highly susceptible to infection by HIV-1. Inhibition experiments with the monoclonal antibody OKT4a demonstrate that this infection is independent of the CD4 molecule.

Antibodies, Monoclonal↗

PubMed1991

Enhancement of monocyte antimycobacterial activity by diethyldithiocarbamate (DTC).

Diethyldithiocarbamate (DTC) has been recently reported to significantly reduce the incidence of opportunistic infections in HIV-infected patients. The present study addresses the question whether DTC is capable of stimulating antimycobacterial activity of mononuclear phagocytes. We found that peripheral blood mononuclear cells (PBMC) of healthy subjects preincubated in vitro with 100-1000 ng/ml of DTC and thereafter infected with Mycobacterium tuberculosis H37Rv or Mycobacterium avium-intracellulare complex exhibited an enhanced antimycobacterial activity compared with control-incubated cells as assessed by the determination of mycobacterial colony-forming units. In subsequent experiments monocytes from healthy volunteers injected with 5 mg/kg body weight of DTC were tested ex vivo for antimycobacterial activity at various periods of time after injection. Injection of DTC resulted in a significant enhancement of antimycobacterial activity which was most evident 24 h after DTC injection. We conclude that DTC stimulates the antimicrobial function of mononuclear phagocytes both in vitro and in vivo. These results may explain the favourable clinical course observed in HIV-infected patients treated with DTC and may serve as a basis for treatment with DTC in patients with drug-resistant atypical mycobacteriosis.

Blood Bactericidal Activity↗

PubMed1991

Expression of transferrin- and interleukin-2-receptors, and HLA-DR in human lung carcinoma.

The expression of HLA-DR and of the receptors for transferrin and interleukin-2 was histochemically analyzed for 27 human lung carcinomas, 3 mesotheliomas, and 3 thymomas by use of the monoclonal antibodies CLONAB Tf-R, Il-2R, and LN3. In addition, a pan B-cell antibody (CD-19) and a pan T-cell antibody (CD3) were applied. The transferrin receptor was found to be expressed in all cases of adenocarcinoma, in 12/17 cases of epidermoid carcinoma, and in a similar percentage of the thymoma cases (2/3). The interleukin-2 receptor specific antibody stained positively only for 3 cases (1 mesothelioma, 1 adenocarcinoma, and 1 epidermoid carcinoma). The expression of HLA-DR could be demonstrated in a similar small percentage of adenocarcinoma and of epidermoid carcinoma, however in 2/3 cases of mesothelioma and thymoma, respectively. The CD-19 antibody stained negatively for all tumor cases, the pan T-antibody positive in 2/10 adenocarcinoma and in 1/3 thymoma. The data suggest that the transferrin receptor may play an important role in human lung tumor growth. In addition, it may be used as diagnostic aid for distinguishing mesothelioma from metastatic adenocarcinoma of lung into the pleura.

Adenocarcinoma↗

PubMed1991

Child psychiatrists' views of DSM-III-R: a survey of usage and opinions.

The DSM-IV Child Psychiatry Work Group surveyed 460 child psychiatrists about their use of DSM-III-R and their reactions to specific proposed nosological revisions for DSM-IV. This paper presents the responses of the sample as a whole and of respondent subgroups with different theoretical, practice, and training characteristics. The survey indicates that DSM-III and DSM-III-R are widely used and generally accepted by child psychiatrists. Ninety-eight percent of respondents believe a criterion-based diagnostic system is useful, and 65% consider DSM-III-R to be an improvement over DSM-III. Depending on the diagnosis 47% to 66% of the respondents reported that they generally assess all applicable criteria and 28% to 49% often refer to the manual before assigning a diagnosis. A majority of respondents supported proposals for several new diagnostic subtypes. Ninety-three percent of respondents indicated that "adequacy of family support" was very valuable for treatment planning or estimating prognosis. Fifty-five percent of respondents admitted to diagnosing adjustment disorders in order to avoid the stigma associated with other disorders. Child psychiatrists who are psychodynamically oriented or practicing in an office-based setting or out of training for more than 10 years tend to use the DSM-III-R less rigorously.

Adolescent↗

PubMed1991

Retinoic acid increases zif268 early gene expression in rat preosteoblastic cells.

In this study we demonstrate that retinoic acid (RA) increases the expression of transcription factor zif268 mRNA in primary cultures of fetal rat calvarial cells and in simian virus 40-immortalized clonal rat calvarial preosteoblastic cells (RCT-1), which differentiate in response to RA, but not in the more differentiated RCT-3 and ROS 17/2.8 cells. The increased expression of zif268 mRNA is rapid (maximal within 1 h), transient (returns to basal levels by 3 h), detectable at RA doses of 10(-12)M, and independent of protein synthesis. The relative stimulation of zif268 mRNA by RA was much larger than that of other early genes, including c-fos, c-jun, and junB. The rate of transcription of RA-stimulated RCT-1 cells, estimated by nuclear run-on assays, was elevated, suggesting that RA regulation of zif268 gene transcription was at least in part transcriptional. Moreover, RA stimulated the transcriptional activity of a Zif268CAT (chloramphenicol acetyltransferase) plasmid containing 632 bp of zif268 5' regulatory sequences in RCT-1 cells but not in the more differentiated RCT-3 cells. These in vitro data support the in vivo observations which localize zif268 and RA receptor-gamma transcripts to bone and cartilage during development, suggesting that both RA and zif268 may play a role in osteoblast differentiation.

Animals↗

PubMed1991

Ber-MAC3: new monoclonal antibody that defines human monocyte/macrophage differentiation antigen.

A new monoclonal antibody Ber-MAC3 is reported. It recognises a formol sensitive epitope of a not yet clustered monocyte/macrophage specific 140 kilodalton glycoprotein that is expressed on the cell surface and in the cytoplasm. In 30 cases of acute and chronic leukaemia, Ber-MAC3 staining was restricted to 15 myeloid leukaemias of M4 and M5 types. The tumour cells of two cases of true histiocytic malignancies were Ber-MAC3 positive, whereas those of all 280 malignancies of lymphocytic origin were negative. The latter included 52 cases of Hodgkin's disease and 41 cases of Ki-1 positive anaplastic large cell lymphomas which had previously been classified as true histiocytic lymphomas. Ber-MAC3 therefore seems to be of considerable value for selective identification of monocytes and macrophages at a certain stage of differentiation and seems to be suitable for diagnosing myelomonocytic or monocytic leukaemia and neoplasms of true histiocytic origin.

Antibodies, Monoclonal↗

PubMed1991

Functional estrogen receptors in osteoblastic cells demonstrated by transfection with a reporter gene containing an estrogen response element.

Although a small number of estrogen receptors (ER) were visualized in osteoblastic cells, and estradiol (E2) has some effects on osteoblasts in vitro, the direct action of E2 on osteoblasts has not been fully established. To determine the presence of functional ER in osteoblasts, we transfected cells with a plasmid containing the chloramphenicol acetyl transferase (CAT) reporter gene and the estrogen-responsive element (ERE) from the vitellogenin A2 gene. E2-dependent induction of CAT activity was determined 48 h after transient transfection and subsequent treatment with 10-100 nM 17 beta-E2. 17 beta-E2, but not 17 alpha-E2, dihydrotestosterone, or progesterone, induced CAT activity in a dose-dependent manner (up to 6-fold) in rat calvarial fraction-3, RCT-3, PyMS, and UMR-106 cells as well as in the human osteosarcoma cell line SaOS-2/B-10. In contrast, E2 had no effect on the induction of CAT activity in the preosteoblastic cell lines RCT-1 and TRAB-11, in the rat osteosarcoma cell line ROS 17/2.8, and in the fibroblastic cell lines BALB-c/3T3 and NRK. Over-expression of ER using a simian virus-40-based expression vector not only conferred or enhanced E2-dependent induction of CAT in all cell types, but augmented E2-dependent expression of insulin-like growth factor-I and E2-stimulated DNA synthesis in primary calvarial and PyMS osteoblastic cells, respectively. These data show the presence of low levels of functional endogenous ER in some, but not all, osteoblastic cells and suggest that the abundance of ER may be rate limiting in the action of E2 on these cells.

3T3 Cells↗

PubMed1991

Estradiol regulation of insulin-like growth factor-I expression in osteoblastic cells: evidence for transcriptional control.

Insulin-like growth factor-I (IGF-I) has anabolic effects on skeletal tissues, acting as both a systemic hormone and an autocrine/paracrine regulator of cellular function. We have previously reported that estradiol (E2) stimulation of rat osteoblast proliferation in vitro was inhibited by IGF-I antibodies. We show here that E2, similar to IGF-I, also increases alpha 1(I) procollagen mRNA levels in primary cultures of rat calvarial osteoblasts. The E2 effect on collagen mRNA lags behind that produced by recombinant IGF-I by about 12 h and was also abolished in the presence of cycloheximide or by the addition of antibodies against IGF-I. Furthermore, 17 beta E2 induced a 2- to 2.5-fold elevation of the level of IGF-I mRNA within 2-4 h, which persisted thereafter. The E2 stimulation of IGF-I mRNA was not blocked by cycloheximide, suggesting that de novo protein synthesis of an intermediate protein was not required. The IGF-I mRNA half-life, estimated by treating the cells with the RNA polymerase inhibitor 5,6-dichloro-1 beta-D-ribofuranosylbenzimidazole, was about 7 h and was not altered by E2 treatment. On the other hand, nuclear run-on assays indicated that E2 increased the transcriptional activity of the IGF-I gene, and this effect was further enhanced in cells overexpressing E2 receptors after transient transfection. These findings suggest that IGF-I may serve as a mediator for the anabolic effects of E2 on bone, and that E2 stimulates IGF-I gene expression at least in part through transcriptional control.

Animals↗