Nuclear transcription factors that bind to elements of the IL-2 promoter. Induction requirements in primary human T cells

Prior studies have identified several elements that contribute to the activity of the IL-2 promoter in the stimulated T cell line, Jurkat. The sites and their corresponding nuclear binding factors include: NF-kappa B, AP-1, AP-3, OCT-1, and NF-AT. The latter "nuclear factor for activated T cells" likely contributes to the tissue specificity of IL-2 gene expression. Using electrophoretic mobility shift assays, we have studied these transcription factors in primary T cells from human blood to verify their presence in a physiologic setting and to identify the signals that stimulate factor activity. All factors are induced in the nuclei of T cells upon activation with mitogens but not with exogenous IL-2 growth factor. However, the signaling requirements and sensitivity to protein synthesis inhibitors differ considerably. Only the activities for NF-AT and AP-1 sites require two signals for optimal induction, i.e., PMA plus either lectin or antibody to the CD3 or CD28 surface molecules. Other factors are induced by lectin, antibody, and/or PMA alone. After appropriate stimulation, both NF-AT and AP-1 are peculiarly sensitive to the protein synthesis inhibitor anisomycin. Our data correlate the activity of NF-AT and AP-1 in gel shift assays with the two signals requirements for IL-2 gene expression.

Nuclear transcription factors that bind to elements of the IL-2 promoter. Induction requirements in primary human T cells

Prior studies have identified several elements that contribute to the activity of the IL-2 promoter in the stimulated T cell line, Jurkat. The sites and their corresponding nuclear binding factors include: NF-kappa B, AP-1, AP-3, OCT-1, and NF-AT. The latter "nuclear factor for activated T cells" likely contributes to the tissue specificity of IL-2 gene expression. Using electrophoretic mobility shift assays, we have studied these transcription factors in primary T cells from human blood to verify their presence in a physiologic setting and to identify the signals that stimulate factor activity. All factors are induced in the nuclei of T cells upon activation with mitogens but not with exogenous IL-2 growth factor. However, the signaling requirements and sensitivity to protein synthesis inhibitors differ considerably. Only the activities for NF-AT and AP-1 sites require two signals for optimal induction, i.e., PMA plus either lectin or antibody to the CD3 or CD28 surface molecules. Other factors are induced by lectin, antibody, and/or PMA alone. After appropriate stimulation, both NF-AT and AP-1 are peculiarly sensitive to the protein synthesis inhibitor anisomycin. Our data correlate the activity of NF-AT and AP-1 in gel shift assays with the two signals requirements for IL-2 gene expression.

Admission to child health surveillance lists: the views of FHSA general managers and general practitioners

OBJECTIVES

To find out the sources of advice that were helpful to managers of family health services authorities in drawing up the criteria for admission of general practitioners to the child health surveillance lists; to determine the criteria used for admission of general practitioners to the family health services authorities' child health surveillance lists; to find out the changes general practitioners have made in child health surveillance in their practices; to determine the experiences of general practitioners relating to admission to the child health surveillance lists and to training in child health surveillance.

DESIGN

Survey by postal questionnaire.

SUBJECTS

General managers of all family health services authorities in England and Wales; all general practitioners in Yorkshire and Humberside.

RESULTS

Managers of 80 of 93 family health services authorities replied (86%). A total of 62 (78%) found local community paediatricians helpful in compiling criteria for admission to child health surveillance lists, and 46 (57%) found national guidelines helpful. Fifty seven (71%) accepted general practitioners who had completed an approved course, and 45 (56%) accepted those with three or more years' experience of child health surveillance. Of the 1966 questionnaires sent to general practitioners, 1233 were satisfactorily completed (63%). Of the 919 respondents who had applied to be put on child health surveillance lists, 673 (73%) had been permanently accepted; of these, 441 (65%) had done an approved course and 375 (56%) had had three or more years' experience of child health surveillance. Of the 145 (16%) not accepted, 57 (39%) had done an approved course and 71 (49%) had three or more years' experience. Respondents reported variable quality and availability of courses in child health.

CONCLUSIONS

Acceptance of general practitioners on to child surveillance lists has not been carried out consistently despite national guidelines setting out criteria for acceptance.

Signs of cellular immunosuppression correlate with HLA-DR phenotypes in healthy HIV-negative homosexuals: preliminary findings

Twelve healthy, anal-receptive, homosexual Caucasian males who were seronegative for HIV antibody were typed for HLA-DR antigens. Flow cytometry was used to immunophenotype peripheral blood lymphocytes bearing the CD4, CD8, LEU7, and combined CD8 and LEU7 antigens. These individuals had reported a large number of sexual partners within a five-year period preceding this study. Each individual was assigned a score based on the Hardy-Weinberg frequency of their HLA-DR phenotype in the Caucasian population. The larger the value of this score, the more common the HLA-DR phenotype, the smaller the score, the rarer the phenotype in the population at large. A significant inverse correlation was observed between this score and the proportion of lymphocytes with CD8 and LEU7 antigens. Lymphocytes bearing these two antigens have in vitro suppressor activity and are elevated in patients with human immunodeficiency virus (HIV) infection. The inverse association between CD8+/LEU7+ cells and frequency of HLA-DR phenotypes is consistent with the hypothesis that individuals with rarer phenotypes whose partners are drawn from the population at large are more likely to be challenged during anal insemination, which results in immunosuppression (alloantigenic challenge hypothesis). On the other hand, it is possible that an association exists between certain HLA-DR phenotypes and immune status. Although these observations were made in a very small sample, we believe that the strength of this association provides justification for further investigation into the possibility that alloantigenic challenge may increase the risk for infection, if exposed to HIV, and augment the immunosuppressive action of HIV once significant infection has occurred.

Osteoinductive potential of human demineralised bone and a bioceramic in abdominal musculature of the rat

Human demineralised cortical bone chips ('bank' bone) and a particulate bioceramic (20% hydroxyapatite: 80% tricalcium phosphate) were implanted into muscle pouches in the rat abdominal wall. Combined implants of both bone and bioceramic were also made. The implants were examined histologically at thirty day intervals over a three month period. The results showed that the hydroxyapatite: tricalcium phosphate bioceramic was not resorbed and did not induce bone formation when implanted alone or in combination with human demineralised bone. In contrast the bank bone was osteogenic but, even at three months, bone formation was sparse. These results are in accord with recent findings that the use of xenogeneic model systems to evaluate the osteogenic potential of human bone is limited.

The effect of immunosuppressive agents on the induction of nuclear factors that bind to sites on the interleukin 2 promoter

Cyclosporin A (CSA), FK506, and glucocorticosteroids all inhibit the production of lymphokines by decreasing lymphokine gene expression. Previous experiments have defined six different sites that may contribute to the transcriptional control of the interleukin 2 (IL-2) promoter, and for each, active nuclear binding factors are induced upon mitogenic stimulation. While dexamethasone markedly blocks the increase in IL-2 mRNA in stimulated human blood T cells, we found that the drug does not block the appearance of factors that bind to the transcriptional control sites termed AP-1, AP-3, NF-kB, OCT-1, B site, and NF-AT. In contrast, both CSA and FK506 have similar effects: the drugs cause modest decreases in AP-3 and NF-kB, and markedly decreases in the activity of AP-1 and NF-AT. Therefore, CSA and FK506, while chemically different, seem to act upon a similar pathway that leads to IL-2 gene expression, whereas glucocorticoids do not affect this pathway.

The responses of superior laryngeal nerve afferent fibres to laryngeal airway CO2 concentration in the anaesthetized cat

In anaesthetized cats, the isolated, in situ, larynx was subjected to a simulated respiratory cycle and the responses of fifty-six superior laryngeal nerve (SLN) afferent fibres to respiration-related stimuli were examined during changes in the fractional CO2 concentration of the laryngeal airway (Faw, CO2). Sensory SLN fibres which displayed low rates of discharge when the larynx was unventilated (quiescent fibres) and which responded to negative laryngeal airway pressure were excited by elevations in Faw, CO2 whereas quiescent fibres responsive to positive laryngeal pressure were inhibited by the same procedure. We propose that changes in airway CO2 levels may play a role in maintaining upper airway patency, especially during sleep.

The effects of changes in laryngeal airway CO2 concentration on genioglossus muscle activity in the anaesthetized cat

In the anaesthetized cat the larynx was isolated in situ, artificially ventilated and used to assess reflex effects exerted by respiration-related laryngeal stimuli on genioglossus electromyographic activity (Gg EMG) and respiratory frequency (RF). Phasic Gg EMG was not observed when the larynx was unventilated but was evoked, with a concurrent decrease in RF, when negative pressures or oscillatory pressures similar to those of normal ventilation were applied to the larynx. Increases in laryngeal airway CO2 concentration also enhanced Gg EMG and reduced RF. All reflex effects were abolished by bilateral section of the superior laryngeal nerves. We propose that negative intralaryngeal pressure and CO2 may act together to restore pharyngeal patency during obstructive apnoea.

Folylpolyglutamates in Leishmania major

The intracellular folates of the protozoan parasite Leishmania major have been examined. About 95% of the exogenous [3H]folate accumulated by the protozoan is metabolized to polyglutamate conjugates within 65 hr, and the intracellular folates are about forty-fold concentrated over the folate in the medium. The predominant metabolite of folic acid is the pentaglutamate conjugate (85%), with lessor amounts of the tetraglutamate (approximately 9%) and hexaglutamate (approximately 3%), and trace (less than 2.5%) amounts of di-, tri- and hepta-glutamate conjugates. Chromatographic properties of the products indicate that the conjugates are linked through the gamma-carboxyl groups. The folylpolyglutamate distribution in Leishmania is similar to that found in mammalian tissues.

Intraarticular iliotibial band reconstruction for anterior cruciate ligament insufficiency

Intraarticular reconstruction of the anterior cruciate ligament by transferring the distal aspect and insertion of the iliotibial band has been clinically successful. Our surgical technique theoretically retains normal neurovascular supply, and thus, the potential for dynamic repair exists. Thirty-five patients, 28 men and 7 women, underwent this reconstruction. The average age was 24 years, with a range from 18 to 46. There were 27 chronic and 8 acute injuries. Pathological findings included an absent anterior cruciate (14 knees), severe stretching (13), failed reconstruction or repair (4), midportion tears (3), and avulsion (1). Postoperative patients were evaluated according to the Kennedy criteria. An anterior drawer of 2+ was not observed in any patient. There were no cases of 2+ rotary instability, and no pivot shifts. The possibility of a dynamic or proprioceptive repair was assessed by electromyography. While no evidence of electrical activity was recorded on the gluteus maximus on 60 normal knee examinations, all 10 tested postoperative iliotibial band patients had electrical activity. The failed results of the series showed no evidence of activity.

A swine stress ulcer model

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