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Biomedical subjects

M A Haque

Publications and source records attributed to M A Haque.

At least 37 records · Page 2Linked to original sources
PubMed1998

Autoreactive CD4- CD8- alpha beta T cells to vaccinate adjuvant arthritis.

Studies suggested that experimental autoimmune diseases can effectively be prevented and treated by application of normal autoreactive T cells or autoreactive T cells in an attenuated form. In this study, several autoreactive CD4- CD8- T-cell clones (A2, A6, and A13 cells) were isolated for the first time from the draining lymph nodes of Lewis rats with adjuvant arthritis (AA). Surprisingly, intraperitoneal inoculation with A13 cells, but not A2 or A6 cells protected rats from AA both clinically and histologically. It was demonstrated that A13 cells were CD4- CD8- alpha beta T cells, and showed proliferative responses to irradiated syngeneic spleen cells (antigen-presenting cells; APC). Interestingly, A13 cells proliferated against concanavalin A (Con A) and staphylococcal enterotoxin B (SEB), but did not show any proliferation to Mycobacterium tuberculosis (Mt), or its 65 000 MW heat-shock protein (HSP). Rats protected from AA by inoculation with A13 cells showed a specific anti-idiotypic delayed-type hypersensitivity reaction compared with other autoreactive T cells (A2 or A6 cells). These findings demonstrate that AA can be suppressed by autoreactive CD4- CD8- alpha beta T cells, and these cells may be used as therapeutic agents in experimental autoimmunity.

Adoptive Transfer↗
PubMed1997

Clonal anergy is a potent mechanism of oral tolerance in the suppression of acute antigen-induced arthritis in rats by oral administration of the inducing antigen.

The effects of oral administration of ovalbumin (OVA) on acute OVA-induced arthritis (OIA) in rats, which is mediated by Arthus reaction to the antigen in the joint space, were investigated. The oral administration of OVA before immunization with OVA significantly suppressed the development of acute OIA in a dose-dependent manner, in accordance with decreases in both the in vivo anti-OVA IgG antibody production and in vitro lymphocyte proliferative responses to OVA. These results were shown in both the single high-dose (200 mg x 1) or the multiple low-dose (200 microg x 5) feeding protocols. In vitro study showed that rat IL-2 could reverse the reduced OVA-specific lymphocyte proliferative responses. The spleen cells obtained from OVA-feeding, unprimed rats neither adoptively transferred the suppression to naive recipient rats nor suppressed the in vitro lymphocyte proliferation. These results demonstrate that the acute OIA can be suppressed by the induction of oral tolerance (OT) to OVA, and strongly suggest that the OT was due to clonal anergy of antigen-reactive T lymphocytes, not the active suppression by OVA-specific regulatory cells.

Acute Disease↗
PubMed1996

Suppression of adjuvant arthritis in rats by induction of oral tolerance to mycobacterial 65-kDa heat shock protein.

Oral administration of mycobacterial 65-kDa heat shock protein (HSP) given daily for 5 days prior to immunization with Mycobacterium tuberculosis (Mt) suppressed the development of adjuvant arthritis (AA) in rats. AA was significantly suppressed by 30 and 300 micrograms HSP, and variably by 0.3, 3 micrograms or 1 mg. Histological analysis of joint samples obtained from control and test rats confirmed the suppression of AA in the fed group. Feeding Mt or hen egg lysozyme (HEL) failed to affect AA, indicating that the suppression was HSP specific. The oral administration of 30 micrograms HSP decreased both delayed-type hypersensitivity (DTH) reactions and proliferative responses to HSP and Mt. In addition, the proliferation of lymph node cells (LNC) from Mt-sensitized rats was inhibited by the addition of spleen cells (SPC) from HSP-fed animals, possibly by the secretion of transforming growth factor (TGF)-beta. Spleen cells obtained from tolerized donors were capable of transferring the tolerance to naive recipients. These results demonstrate that feeding HSP is an effective way to suppress AA and that the suppression of AA may be mediated by regulatory T cells generated following oral administration of mycobacterial 65-kDa HSP.

Administration, Oral↗
PubMed1996

Developmental patterns of O2 consumption, heart rate and O2 pulse in unturned eggs.

The effects of failure to turn eggs on the developmental patterns of oxygen consumption (MO2), heart rate (fH) and O2 pulse during the second half of incubation of individual chicken eggs were examined. The MO2 of unturned eggs increased at a significantly lower rate than the control toward the end of prenatal incubation, and the plateau MO2 between day 17 and 19 was significantly lower than the control. Lack of turning also resulted in significant changes in the developmental patterns of fH and O2 pulse. It is suggested that the effects of lack of egg-turning on the developmental patterns of MO2 may be attributable to lower embryonic growth rate in addition to impairment of gas exchange through the chorioallantoic gas exchanger.

Agriculture↗
PubMed1996

Effects of pre-incubation egg storage on embryonic functions and growth.

The effect of pre-incubation storage on physiological functions of chick embryos during the last half of incubation and the relationship to embryonic growth were studied. In the first experiment, eggs were stored for 20 or 30 days, respectively, and the developmental patterns of oxygen consumption (MO2), heart rate (fH) and O2 pulse of individual embryos were examined. The MO2 of stored eggs increased at significantly lower rate than the control between day 12 and 17 of incubation, and the stored eggs had a significantly lower plateau MO2 between day 17 and 19. The decrease in MO2 of some stored eggs was correlated with late incubation mortality. Pre-incubation storage also resulted in significant changes in the developmental patterns of fH and O2 pulse. In the second experiment, the eggs were stored for 10 and 20 days, respectively, to also examine the effect of short-term storage on the development of MO2 in relation to embryo growth. Pre-incubation storage for 10 days had no significant effect, but 20 days storage shifted developmental patterns of MO2, wet mass, dry mass and embryo water fraction to the right of the control. Furthermore, MO2 was significantly lower than expected on the basis of embryo mass after day 17 of incubation. Prolonged pre-incubation storage caused not only a rightward shift in MO2 pattern due to retarded growth, but also severe depression of MO2 during the last stages of prenatal development.

Agriculture↗
PubMed1996

Effect of growth condition on in-vitro susceptibility of Shigella dysenteriae type 1 killing by murine peritoneal macrophages.

The intracellular fate of Shigella dysenteriae type 1 strains grown in casamino acid-yeast extract (CYE) broth and nutrient broth (NB) was studied in casein-elicited mouse peritoneal macrophages. Virulent strains 14731 and W30864 cultured in NB and opsonised with normal mouse serum were susceptible to killing by peritoneal macrophages (66 SEM 1.7% killing by 2 h). In contrast, both strains grown in CYE broth and opsonised with normal mouse serum showed resistance to killing by peritoneal macrophages (76 SEM 1.4% survival by 2 h). Electronmicroscopy demonstrated that the bacteria escaped from the phagosome compartment by lysing the phagocytic vacuole and remained within the cytoplasm. Lipopolysaccharide (LPS) stimulated peritoneal macrophages to kill the opsonised strains 14731 and W30864 grown in CYE broth (85.4 SEM 1.6% killing by 2 h). Recombinant murine gamma interferon (rIFN-gamma) also stimulated macrophages to kill CYE-grown bacteria (52.1 SEM 1.3% killing by 2 h). However, an avirulent rough mutant strain W30864-22 grown in either NB or CYE broth showed marked susceptibility to killing by peritoneal macrophages, which was similar to that of NB-grown strain 14731 or W30864. The results of the present study suggest that in-vitro growth conditions may modulate the susceptibility of S. dysenteriae type 1 to killing by phagocytes.

Animals↗
PubMed1996

Acetabular labral tears: evaluation with MR arthrography.

PURPOSE: To determine the usefulness of magnetic resonance (MR) arthrography in the diagnosis of acetabular labral tears. MATERIALS AND METHODS: MR arthrography of the hip was performed in 10 patients who underwent subsequent surgical evaluation. Eight arthrograms were obtained with intraarticular administration of gadolinium solution and two with intraarticular administration of normal saline. T1-weighted spin-echo (intraarticular gadolinium) or T2-weighted gradient-echo (intraarticular normal saline) images were obtained in the axial, sagittal, and coronal planes with use of a surface coil. Criteria for labral tears included labral blunting, absence, displacement, intrasubstance contrast material, and contrast material at the acetabular-labral junction. Labra with enlargement, intrasubstance intermediate signal intensity, or irregular margins were interpreted as degenerative. RESULTS: Labral tears were diagnosed in eight hips. Tears included six labra with contrast material that tracked at the acetabular-labral junction, one of which had associated intrasubstance extension. One tear was confined to the labral substance. The other tear exhibited absent labral tissue and an irregular remnant. One degenerative labrum and one normal labrum were identified. All MR arthrographic findings were confirmed at surgery. Extension of one anterosuperior tear into the posterosuperior labrum was not prospectively appreciated. CONCLUSION: In this preliminary study, MR arthrography appears to be a promising imaging modality for accurate diagnosis of acetabular labral tears.

Acetabulum↗
PubMed1996

Effect of culture conditions on the susceptibility of enteroaggregative Escherichia coli to human serum and polymorphonuclear leucocytes.

Recent work has indicated that the pathogenicity of enteroaggregative Escherichia coli (EAggEC) is strictly regulated by environmental conditions. The growth conditions, susceptibility to the bactericidal activity of serum, and polymorphonuclear leucocytes (PMN) using strains of EAggEC grown in two different culture conditions were examined. Strains of EAggEC grown in casamino acids-yeast extract (CYE) broth at 37 degrees C for 20 h showed resistance to killing by human serum (86.8 +/- 6.9% survival by 2 h) and PMN (67 +/- 5.1% survival by 2 h). In contrast, these strains grown in nutrient broth (NB) showed sensitivity to serum (98.9 +/- 0.5% killing by 2 h) and PMN (98.9 +/- 0.5% killing by 2 h). EAggEC strains cultured in NB became resistant to killing by serum when mixed with extracellular material extracted from the bacteria grown in CYE broth. These results indicate that the growth condition may modulate the sensitivity of EAggEC, and the promotion of extracellular material formation in CYE broth is responsible for the resistance to killing by serum and PMN.

Blood Bactericidal Activity↗
PubMed1995

Surface components of shigellae involved in adhesion and haemagglutination.

Strains of Shigella species were studied for their ability to adhere and agglutinate mammalian erythrocytes. Shigella dysenteriae and Sh. flexneri exhibited haemagglutinating (HA) properties when cultured in Casamino Acids-Yeast Extract (CYE) broth in the presence of 1 mmol 1-1 calcium chloride, but other shigellae did not show this property under the same culture conditions. Repeated subcultivation of Sh. boydii, Sh. sonnei and HA negative strains of Sh. dysenteriae and Sh. flexneri in CYE broth medium induced adhesive and haemagglutinating properties that were inhibited by sodium periodate. HA activities of Shigella spp. were also inhibited by N-acetylneuraminic acid, alpha 1-glycoprotein and fetuin, but not by protease. Electron microscopy of Sh. dysenteriae 1, Sh. flexneri 2a, Sh. boydii 12 and Sh. sonnei 1 grown in CYE broth showed the presence of an extracellular slime layer that promoted agglutination of erythrocytes. The slime layer extracted from the cell surface of Shigella spp. showed HA properties, whereas lipopolysaccharide (LPS) obtained from the same strains, except Sh. dysenteriae 1, did not agglutinate erythrocytes. This evidence suggests that the cell surface haemagglutinin is a loosely bound slime layer which is expressed in CYE broth medium.

Animals↗
PubMed1994

Contact hemolysin production by strains of enteroaggregative Escherichia coli isolated from children with diarrhea.

Forty-five strains of enteroaggregative Escherichia coli were tested for hemolytic activity with different culture media and erythrocytes from different species. Thirty-seven strains showed proteinase K-sensitive contact hemolysin activity with sheep erythrocytes when cultured in Casamino Acids-yeast extract broth supplemented with 1 mM calcium chloride and when cultured in nutrient broth media. The production of contact hemolysin was dependent on temperature, pH, and culture conditions.

Animals↗
PubMed1993

Role of Shigella dysenteriae type 1 slime polysaccharide in resistance to serum killing and phagocytosis.

Shigella dysenteriae type 1 produce a slime polysaccharide when cultivated in vivo in adult rabbit ileal loops or in vitro in casamino acid yeast extract broth medium which promotes hemagglutination of these bacteria. Seven strains of S. dysenteriae 1 grown in vitro and in vivo and possessing slime polysaccharides resisted killing by normal human serum as compared to bacteria grown under conditions which do not stimulate the production of capsular polysaccharide and did not resist serum killing (mean survival 72% for in vitro growth and 73% for in vivo growth conditions favoring capsule production vs < 2% for growth conditions which do not favor capsule production; P < 0.001 for both comparisons). Similar differences were observed when killing was assessed by phagocytosis (62-78% vs < 2%; P < 0.001). We conclude that capsular polysaccharide may be an additional virulence factor of S. dysenteriae 1.

Animals↗
PubMed1977

Mechanical suture methods in thoracic and abdominal surgery.

Mechanical suturing procedures on the bowel, lung, bronchi and pulmonary vessels have been used on 264 occasions in 180 thoracic and abdominal operations. The instruments proved simple to use and produced reliable good quality closures, for the most part without manual reinforcement. There were 2 technical failures, one ending fatally, after colo-colostomy. Two minor postoperative suture leaks were encountered in 122 operations on the alimentary tract, but no leakage or other problem has arisen in 58 pulmonary cases. The staple-suturing methods described are safe and straightforward, and it is believed that they represent a significant advance in the techniques of thoracic and abdominal surgery, which can usefully be applied in many situations.

Abdomen↗