Beneficial effect of recombinant human growth hormone on the intestinal mucosa barrier of septic rats

The objective of the present study was to investigate the effects of recombinant human growth hormone (rhGH) on the intestinal mucosa barrier of septic rats and explore its possible mechanism. Female Sprague-Dawley rats were randomized into three groups: control, Escherichia coli-induced sepsis (S) and treatment (T) groups. Groups S and T were subdivided into subgroups 1d and 3d, respectively. Expression of liver insulin-like growth factor-1 (IGF-1) mRNA, Bcl-2 and Bax protein levels and the intestinal Bax/Bcl-2 ratio, and plasma GH and IGF-1 levels were determined. Histological examination of the intestine was performed and bacterial translocation was determined. rhGH significantly attenuated intestinal mucosal injuries and bacterial translocation in septic rats, markedly decreased Bax protein levels, inhibited the decrease of Bcl-2 protein expression and maintained the Bax/Bcl-2 ratio in the intestine. rhGH given after sepsis significantly improved levels of plasma GH (T1d: 1.28 ± 0.24; T3d: 2.14 ± 0.48 æg/L vs S1d: 0.74 ± 0.12; S3d: 0.60 ± 0.18 æg/L; P < 0.05) and IGF-1 (T1d: 168.94 ± 65.67; T3d: 201.56 ± 64.98 æg/L vs S1d: 116.72 ± 13.96; S3d: 107.50 ± 23.53 æg/L; P < 0.05) and expression of liver IGF-1 mRNA (T1d: 0.98 ± 0.20; T3d: 1.76 ± 0.17 vs S1d: 0.38 ± 0.09; S3d: 0.46 ± 0.10; P < 0.05). These findings indicate that treatment with rhGH had beneficial effects on the maintenance of the integrity of the intestinal mucosa barrier in septic rats.

Bronchial responsiveness of aged asthmatic patients to bronchodilator and methacholine.

Geriatric asthma is characterized by prolonged illness, lower remission rate, poor response to therapy and higher mortality rate. We studied bronchodilator response and methacholine challenge in 25 aged non-smoking asthmatic patients; thirty-two young asthmatic patients were included as control. The elderly patients had poorer baseline pulmonary function and were more responsive to a bronchodilator than the younger patients. The response to bronchoprovocation did not show any difference between the two groups. Our findings suggested that the airways of elderly asthmatics are as sensitive as those of younger patients and should not be under-treated.

The modulatory effect of antigen- and PAF-induced asthmatic reaction by aerosol administration of OKY-046 in guinea pigs.

The therapeutic effect of a thromboxane A2 (TXA2) synthetase inhibitor on asthma is still controversial. This study was aimed at clarifying its effect on asthmatic reactions in guinea pigs. Both ovalbumin (OVA)- and platelet activating factor (PAF)-induced dual phase airway spasm and hyperreactivity in guinea pigs were used as the asthma model. Our results demonstrated that aerosol administration of OKY-046 could inhibit both OVA- and PAF-induced late phase bronchoconstriction and airway hyperreactivity to methacholine in OVA sensitized guinea pigs. PAF administration could also induced dual phase bronchoconstriction in normal guinea pigs. Similarly, late phase airway spasm and airway hyperreactivity after PAF exposure was also blocked by OKY-046. In conclusion, aerosol administration of OKY-046 is a safe and effective way to modulate OVA- and PAF-induced asthmatic reactions. The protective effect of OKY-046 on OVA- and PAF-induced late phase bronchoconstriction and airway hyperreactivity indicates that TXA2 might play an important role in the late phase asthmatic reaction and airway hyperreactivity. The normalization of PAF-induced airway hyperreactivity by OKY-046 also indicates that PAF induced airway inflammation might be through the generation of TXA2.

The inhibitory effect of methotrexate on PAF-induced neutrophil and eosinophil locomotion in asthmatic patients.

We have tested the effect of methotrexate (MTX) on platelet activating factor (PAF)-induced neutrophil and eosinophil locomotion, neutrophil leukotriene B4 (LTB4) generation and mononuclear cell DNA synthesis. Neutrophils from patients treated with low dose methotrexate showed reduced PAF-induced chemotactic responses (727.8 +/- 72.2/10 HPF vs 481.9 +/- 87.3/10 HPF, p < 0.05). Both MTX and the specific PAF antagonist BN-52021 significantly inhibited PAF-induced eosinophil and neutrophil locomotion in a dose-dependent manner. MTX also reduced calcium ionophore-driven LTB4 generation from the neutrophils of asthmatics (358.9 +/- 39.5 pg/10(6) cells vs 240.1 +/- 29.1 pg/10(6) cells, p < 0.05) and attenuated PHA-induced mononuclear DNA synthesis as shown by a reduction in 3H-thymidine uptake and propidium iodide staining. These findings support the view that the beneficial effects of MTX in asthma may be due not only to its anti-mitotic effects on the proliferation of mononuclear cells but also to direct effects on granulocyte locomotion and production of LTB4.

The modulatory effect of immunoglobulin G on the CD23 and HLA-DR expression and cytokine production in different groups of asthmatic patients.

The therapeutic effect and mechanism of action of immunoglobulin G (IgG) on bronchial asthma are not defined. Recently, it has been proposed that mononuclear cell (MNC) infiltration in the airway plays a role in the pathogenesis of asthma. In this study, we evaluated the effect of IgG on the cell receptor expression and cytokine production of MNC from two groups (young atopic and old non-atopic) of stable asthmatic patients. MNCs from both asthmatic patients and normal healthy individuals were obtained after Ficoll-Hypaque separation. Cells were cultured in serum free AIM-V medium, with or without phytohemagglutinin (PHA, 5 micrograms/ml) and IgG (100 micrograms/ml). After culture, MNCs were harvested and stained with monoclonal antibodies for HLA-DR (Ia), CD23 and CD3. MNC supernatants were collected for IL-2 and IL-4 measurement. The results showed an enhancing effect of IgG on young atopic MNC proliferation when stimulated with PHA. The production of IL-2 and IL-4 from MNCs were significantly higher in old non-atopic asthmatics after PHA stimulation. The CD23, but not HLA-DR, expression on CD3 positive T cells and cytokines (IL-2 and IL-4) production were increased by IgG when stimulated with PHA in young atopic asthmatics. To the contrary, the effect of IgG on PHA stimulated MNC proliferation, CD23 and HLA-DR expression on CD23 positive T cells in old non-atopic asthmatics were trivial. Only IL-4 production can be significantly inhibited by IgG. These results suggested that the therapeutic effect of IgG on asthmatics might be variable in different groups of asthmatics.(ABSTRACT TRUNCATED AT 250 WORDS)

Enhanced eosinophil luminol-dependent chemiluminescence and complement receptor expression by platelet-activating factor and interleukin-5.

The cytokine interleukin-5 (IL-5) and the lipid mediator platelet-activating factor (PAF) have both been shown to be involved in eosinophil differentiation and activation. We have measured and compared the effect of PAF and IL-5 on human eosinophils in terms of their luminol-dependent chemiluminescence (CL) response and their expression of complement receptors, CR1 and CR3. Both IL-5 and PAF enhanced the eosinophil CL response. The optimal concentrations were 40 U/ml for IL-5, and 10(-6) M for PAF. The priming effect of IL-5 was slow and reached a maximal response after 90 minutes incubation. In contrast, the effect of PAF peaked early and declined during incubation. In the complement receptor study, only PAF was able to enhance CR3 expression (p < 0.05) while the effect of IL-5 on eosinophil complement receptor expression was negligible. These results provide evidence that both inflammatory mediator (PAF) and cytokine (IL-5) can activate eosinophils but the effects of IL-5 and PAF on eosinophil CL response appear to be distinct. The activation of eosinophils by PAF and IL-5 may occur through different mechanisms.

The influence of microtiter plates from different suppliers on lymphocyte proliferation.

Microtiter plates have been popularly used for lymphocyte culture, but the influence of culture plates from different sources has not been investigated. In this study, the degree of mitogen-induced cell proliferation was investigated using six different brands of flat-bottomed plates. Lymphocytes from twelve normal donors were cultured for 96 hours with several mitogens including PHA, Con A and PWM. Spontaneous cell proliferation was slow and it did not differ significantly among the different plates. However, mitogen-induced cell proliferation showed a wide variation among the six types of plates used. The importance of selecting certain kinds of plates for specific purposes is emphasized.

Effects of gastric cancer cells on lymphocyte proliferation.

Lack of lymphocyte infiltration into gastric cancer tissue appears to be an ominous prognostic indicator. The effects of gastric cancer cells on PHA-induced lymphocyte proliferation were studied. Peripheral lymphocytes were co-cultured for 72 hours with either gastric cancer cells or normal mucosal cells. Pairs of cancerous and normal mucosal cells from stomachs of eight patients, were separately co-cultured with peripheral lymphocytes either from patients or from normal volunteers. The degree of PHA-induced lymphocyte proliferation was measured by 3H-thymidine incorporation. The lymphocyte proliferation was inhibited by the presence of either gastric cancerous or normal mucosal cells in a dose-related manner. The lymphocytes from the normals proliferated twice as much as did the lymphocytes from the patients. The isotope incorporation occurred in lymphocytes rather than in gastric cells since the later incorporated insignificant amounts of isotope. There was no difference between gastric cancerous or normal mucosal cells inhibiting the proliferation of either normal or patients' lymphocytes (p greater than 0.05). In conclusion, gastric cancerous cells (up to 10(6)/ml) have no enhanced inhibition on lymphocyte proliferation when compared with normal gastric mucosal cells.

Alterations of humoral immunity in patients with gastric cancer.

For better understanding of the alterations of humoral immunity in gastric cancer patients, IgG, IgA, IgM, complement C3, C4, CH50, natural antibody (isohemagglutinin-IgM class), ESR, CRP, albumin and globulin were quantitated in sera taken preoperatively from 81 patients with gastric cancer and from 29 control patients with hernia. The results from patients with gastric cancer were grouped according to pTNM staging (including stage I + II, III, and IV). Serum globulin and IgG levels in all stages of cancer patients were significantly lower than that of the controls (p less than 0.05). The CRP and ESR levels in stage III and IV cancer patients were significantly higher (p less than 0.05). There was no difference between cancer and hernia patient groups in IgA, IgM, isohemagglutinin-IgM class, C3, C4, CH50, albumin, WBC and total lymphocyte counts. In conclusion, the significant changes in humoral immunity in patients with gastric cancer include: (1) decrease in serum IgG and globulin levels, and (2) increased levels of acute phase reactants (ESR, CRP). These results imply that patients with gastric cancer have lower acquired humoral immunity and have acute phase reactions.

Modulation of lymphocyte proliferation by murine liver extract.

Murine liver extract (LEx) purified by ammonium sulfate (45-70% saturation) possesses a strong inhibitory effect on human lymphocyte proliferation. We have shown that the inhibitory effect of LEx is not via a cytotoxic effect and that it is proportional to the length of incubation with LEx. Mitogen-prestimulated lymphocytes are more resistant to LEx inhibition than cells not prestimulated. B cells stimulated by PWM are more susceptible to LEx-induced inhibition than PHA- or Con A-stimulated T cells. In Con A cultures, there may be a population of cells more resistant to LEx inhibition. This population is not yet identified. The degree of reversibility of LEx inhibition was different in cells prestimulated by different mitogens. The inhibitory activity of LEx decreased in the presence of an increasing number of cells in the culture.