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Biomedical subjects

A U Haq

Publications and source records attributed to A U Haq.

31 records · Page 2Linked to original sources
PubMed1988

Failure of hydrocortisone to suppress the interferon-gamma-induced augmentation of interleukin 1 secretion of aged human monocytes.

The combined effect of hydrocortisone (HC) and interferon-gamma and -alpha (IFN-gamma and -alpha) on human blood monocytes (Mo) interleukin 1 (IL 1) secretion was investigated. IL 1 was generated by treating the fresh or aged Mo with lipopolysaccharide (LPS), and quantitated by radioimmunoassay (RIA). Hydrocortisone, at the pharmacological attainable concentration of 10(-5) molar (M), markedly suppressed fresh Mo IL 1 secretion but had no effect at lower tested doses. Addition of IFN-gamma enhanced the IL 1 secretion of fresh Mo; however, the simultaneous addition of 10(-5) M HC and IFN-gamma resulted in marked suppression of the monokine release. Monocytes, when cultured in vitro for three days, lost the capacity to secrete IL 1. The loss of IL 1 secretory potential of aged Mo was prevented by preincubating them with IFN-gamma prior to LPS stimulation. IFN-alpha was ineffective in this regard. Aged Mo, pretreated with the combination of IFN-gamma and HC were still able to secrete abundant quantities of IL 1, demonstrating the failure of HC to suppress the IFN-gamma-induced augmentation of IL 1 secretory potential. Even suprapharmacologic doses of HC (10(-4) M) did not inhibit this enhancement and actually further augmented it. Thus, therapeutic concentrations of HC suppress IL 1 secretion of fresh Mo even in the presence of IFN-gamma; however, therapeutic or suprapharmacologic concentrations of HC do not inhibit the IL 1 secretory capacity of IFN-gamma-treated aged Mo.

Cell Survival↗
PubMed1987

Local peritoneal factors: their role in infertility associated with endometriosis.

In order to detect peritoneal abnormalities that could account for infertility associated with endometriosis, 122 infertile individuals were studied at the time of laparoscopy for diagnostic purposes or for in vitro fertilization. Four groups were defined: group 1, laparoscopy without endometriosis; group 2, laparoscopy with endometriosis; group 3, in vitro fertilization without endometriosis; and group 4, in vitro fertilization with endometriosis. Mean peritoneal fluid volume was greater, although not significantly so, in group 4 (29.0 +/- 6.6 ml, mean +/- SEM) than in group 3 (18.2 +/- 2 ml). The concentration and total number of pelvic macrophages were similar for groups 1 and 2. The total number of pelvic macrophages was increased in group 4 (16.9 +/- 4.2 x 10(6)) versus group 3 (10.0 +/- 1.8 x 10(6)) (p = 0.08). The mean sperm phagocytosis in vitro did not differ among the four groups studied. Interleukin 1 activity within the peritoneal fluid and the in vitro interleukin 1 production rate did not differ between individuals with and without endometriosis. Peritoneal fluid and macrophage supernatants from individuals with endometriosis were not embryotoxic when studied in an in vitro mouse embryo system.

Adult↗
PubMed1986

Invasion of paranasal sinuses by Aspergillus oryzae.

A 24-year-old male patient receiving chemotherapy for acute promyelocytic leukemia developed fever, right periorbital swelling and mild right proptosis. A head scan showed opacification of the right maxillary and ethmoid sinuses with adjacent soft tissue swelling. Biopsy of the nasal mucosa demonstrated the typical septate hyphae of Aspergillus species which was later shown on culture to be Aspergillus oryzae. A. oryzae has only rarely been reported in human disease and there is confusion as to its precise identification and role. We would like to confirm the pathogenicity of A. oryzae with this uncommon presentation of aspergillosis and also emphasize the need to take adequate and multiple cultures in suspected cases so that the possibility of species identification will be maximized.

Adult↗
PubMed1986

Role of IFN-gamma and alpha in IL 1 synthesis and secretion of in vitro differentiated human macrophages: a comparative study.

Human blood monocytes (Mo) cultured in vitro differentiate to macrophages (Mx) and lose the capacity to secrete interleukin 1 (IL 1) in response to endotoxin (LPS). Incubation of Mo with interferon gamma or alpha (IFN-gamma or IFN-alpha) prevented this loss of IL 1 secretory potential during the first 24 h of culture. However, there were marked differences between the two interferons if culture period was extended beyond 24 h. Incubation of Mo with IFN-gamma for 48 or 72 h induced IL 1 release in response to LPS in all the donors without exception. In contrast, 48-h incubation of Mo with IFN-alpha alpha caused IL 1 secretion (in response to LPS) in only a minority of donors, while 72-h incubation resulted in very little or no IL 1 release in all the individuals tested. Moreover, only IFN-gamma had the capacity to reinduce IL 1 secretory potential in Mx which had lost the capacity to secrete IL 1 during previous culture. These and other results suggest that IFN-alpha differs from IFN-gamma in being: a less potent IL 1 inducer, ineffective in maintaining IL 1 secretory capacity of fresh Mo for more than 48-72 h, completely unable to reinduce IL 1 secretory potential in culture-derived Mx. Thus, the two species of IFN appear to have a markedly different role in IL 1 synthesis and secretion.

Cell Differentiation↗
PubMed1986

The effect of IFN-gamma and alpha on Con-A stimulated T-cell proliferation: role of monocytes.

Interferon gamma (IFN-gamma) and alpha (IFN-alpha) have been shown to influence T-cell proliferation in several systems. Since both species of IFN affect monocyte (Mo) functions, it is conceivable that these effects are mediated through Mo. In the present study, the effect of IFN-gamma and alpha on concanavalin A (Con A)-driven T-cell proliferation was investigated under suboptimal culture conditions. T-cell proliferation was augmented by IFN-gamma. The stimulatory effect of IFN-gamma was Mo mediated and required the pretreatment of Mo with IFN-gamma prior to co-culture with T-cells. Addition of IFN-gamma during co-culture or pretreatment of T-cells with IFN-gamma was ineffective in achieving augmentation. IFN-gamma induced enhanced T-cell proliferation was not due to increased interleukin-I (IL-I) production by Mo pretreated with IFN-gamma, because addition of IL-I to control Mo-T-cells co-culture failed to increase T-cell proliferation. In contrast, IFN-alpha suppressed T-cell proliferation. The inhibitory effect of IFN-alpha was not mediated through Mo and could be achieved by preincubating the T-cells with IFN-alpha. These results demonstrate opposing effects of the two species of IFN on Con A-driven T-cell proliferation. In addition, Mo play an obligatory role in IFN-gamma induced stimulation, whereas Mo-IFN-alpha interaction is not required for IFN-alpha mediated suppression of T-cell proliferation.

Cells, Cultured↗
PubMed1986

1,25-Dihydroxyvitamin D3 (calcitriol) suppresses IL-2 induced murine thymocyte proliferation.

1,25-dihydroxyvitamin D3 (Calcitriol) inhibits mitogen stimulated T cell proliferation by blocking the production of Interleukin-2 (IL-2). The present study was initiated to determine whether the action of calcitriol was limited only to inhibition of IL-2 production, or if it influenced other events as well. To avoid the use of lectins, thymocytes from CD-I Swiss mice were chosen, which proliferate in response to Interleukin-I (IL-I) or IL-2 without the addition of lectins. Calcitriol inhibited (80-90%) IL-I induced CD-I mouse thymocyte proliferation, whereas 25-OH-D3 was ineffective. Further addition of IL-I failed to overcome this suppression. Surprisingly, calcitriol also inhibited IL-2 induced thymocyte proliferation (60-80%). Further addition of IL-2, in the presence of calcitriol, was ineffective in enhancing thymocyte proliferation. Similar results were obtained with C57BL/10 mouse thymocytes. Additional studies excluded the possibilities that calcitriol mediated inhibition was due to calcitriol IL-2 binding or damage to thymocytes by calcitriol. Thus, calcitriol not only blocks IL-2 production, but these results strongly suggest, that it also interferes with IL-2-thymocyte interaction, which in turn results in inhibition of thymocyte proliferation.

Animals↗
PubMed1985

The effect of gamma interferon on IL-1 secretion of in vitro differentiated human macrophages.

After being cultured overnight, human monocytes lose their ability to secrete interleukin-1 (IL-1) when stimulated by lipopolysaccharide (LPS). However, when these monocytes were cultured for up to 9 days with various concentrations of interferon-gamma (IFN-gamma), these cells were found to retain their ability to secrete appreciable amounts of IL-1 on LPS stimulation. However, the effect was observed only if the monocytes were exposed to the IFN before LPS stimulation and simultaneous addition of IFN and LPS to macrophages was ineffective. This effect of IFN-gamma was related to the concentration of IFN added to the cultures and was completely neutralized by a monoclonal antibody to IFN-gamma. In addition to inducing IL-1 secretion, IFN-gamma also appeared to increase the overall production of IL-1, since reinduction of IL-1 secretion was not associated with a decrease in intracellular IL-1 content. When these macrophages were initially cultured with IFN-gamma, washed, and further cultured with IFN free medium, these macrophages were found to progressively lose their capacity to secrete IL-1 in response to LPS. Conversely, when monocytes were initially cultured in medium free of IFN, washed, and then further cultured in new medium, but now containing IFN-gamma, these macrophages were found to regain their capacity to secrete IL-1. However, the amount of reinduced IL-1 secretion decreased as the length of the initial culture period without IFN increased, with less than optimal IL-1 secretion occurring if monocytes were allowed to mature for 6 days before IFN-gamma pretreatment. In summary, these studies suggest that IFN-gamma may be important in enhancing IL-1 production and secretion by maturing macrophages and tissue macrophages and consequently may play a role in regulating the accessory cell activity of these cells for a variety of immune responses in vivo.

Antibodies, Monoclonal↗
PubMed1984

Interleukin 1 secretion is not required for human macrophage support of T-cell proliferation.

Interleukin 1 (IL-1) is a soluble factor secreted by stimulated monocytes (Mo) and animal macrophages (Mx). We have previously demonstrated that human Mo cultured in vitro for 1-6 days transform to Mx, and retain their ability to support concanavalin A (Con A)-driven T-cell proliferation. We have also shown that, paradoxically, these Mx do not secrete IL-1, when stimulated by endotoxin (LPS). In this study we examined two alternative hypotheses: T cells plus mitogen induce Mx IL-1 production, and human Mx deliver a second signal to T cells via a non-IL-1 mechanism. IL-1 was assayed in a mouse CD-1 thymocyte system without concanavalin A. Mo/Mx were cultured with T cells at low (2 X 10(4)/200 microliters) or high (1 X 10(5)/200 microliters) concentrations for 2 or 4 days, in the presence of Con A. Six hours prior to quantitation of proliferation, 50 microliters of supernatant was removed and assayed for IL-1. As expected both Mo and Mx enhanced T-cell proliferation eight- to tenfold. Mo secreted large amounts of IL-1; there was no demonstrable IL-1 activity present in supernatants from cultures containing either T cells and Mx, or Mx alone. Similar results were obtained by preincubating the cells (Mo, Mx, and T cells) with Con A for 12 hr and removing Con A prior to a 36-hr coculture. We examined the possibility that a small amount of IL-1 may be able to support Con A-stimulated T-cell proliferation and yet may not induce thymocyte proliferation. The highest dilutions of Mo supernatant (1:125) which supported T-cell proliferation also caused a fivefold increase in thymocyte proliferation. Supernatants from Mx failed to stimulate thymocyte proliferation or support Con A-driven T-cell proliferation. However, Mo and Mx lysates contain Il-1 activity. We conclude that human Mx support Con A-induced T-cell proliferation in the absence of IL-1 secretion. Mx may support T-cell proliferation by cell-bound IL-1 or by a non-IL-1 mechanism.

Cells, Cultured↗
PubMed1984

Immunization of guinea pigs against Entamoeba histolytica using glucan as an adjuvant.

Beta 1-3 polyglucose or glucan, an extract of cell wall of Saccharomyces cerevisiae, has been successfully employed in this laboratory as an effective immunopotentiator in experimental studies on amoebiasis. An antigen extract from Entamoeba histolytica was combined with beta, 1-3 glucan for immunizing guinea pigs. In order to study the effectiveness of such vaccine preparations, several batches of guinea pigs were immunized with amoeba antigen alone, and in combination with various immunoadjuvants. Antigen inoculations were carried out via intraperitoneal route. Protective immune responses were obtained against amoeba antigen by using glucan as an adjuvant partner. The study showed that glucan can be safely used as an effective immune enhancer.

Adjuvants, Immunologic↗
PubMed1984

Detection of amoebic antibodies using fractionated antigen in TIA and IHA tests.

Thin layer immunoassay (TIA) test was used to detect anti-amoebic antibodies in the sera obtained from immunized guinea pigs. A few human sera samples were also used for antibody detection. The TIA and IHA results with whole amoeba antigen and fractionated antigen preparations were compared. Both test procedures gave better results with fractionated antigen. The results in TIA were better than in IHA tests. Thin layer immunoassay technique can be conveniently used as an alternative to IHA test for the detection of anti-amoebic antibodies.

Animals↗
PubMed1983

T-cell subset modulation of blood erythroid burst-forming unit proliferation.

Peripheral blood BFU-E are primitive erythroid progenitor cells that have been reported to exhibit an absolute dependence on T-cells for proliferation in the plasma clot system. The study reported here was undertaken to define the differential effects of TS and TH lymphocytes on proliferation of BFU-E. We investigated the effect of unfractionated T-cells, TS, and TH on in vitro growth of peripheral blood BFU-E. Cell populations were negatively selected by treatment with murine monoclonal antibodies (OKT-3, OKT-4, OKT-8) and C'. Our experiments suggest that proliferation of peripheral blood BFU-E exhibits an absolute requirement for T-cells. The capacity to enhance growth of BFU-E is approximately equal between normal unfractionated T-cells and TS and TH cells. The data suggest that the TH and TS cells defined by the OKT antibodies are not critical in the modulation of erythroid proliferation.

Colony-Forming Units Assay↗