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Biomedical subjects

M A Qureshi

Publications and source records attributed to M A Qureshi.

At least 19 recordsLinked to original sources
PubMed2006

Effects of carbenoxolone on heart rhythm, contractility and intracellular calcium in streptozotocin-induced diabetic rat.

Cardiac dysfunction is a frequently reported complication of clinical and experimental diabetes mellitus. Streptozotocin (STZ)-induced diabetes in rat is associated with a variety of cardiac defects including disturbances to heart rhythm and prolonged time-course of cardiac muscle contraction and/or relaxation. The effects of carbenoxolone (CBX), a selective gap junction inhibitor, on heart rhythm and contractility in STZ-induced diabetic rat have been investigated. Heart rate was significantly (P < 0.05) reduced in Langendorff perfused spontaneously beating diabetic rat heart (171+/-12 BPM) compared to age-matched controls (229+/- 9 BPM) and further reduced by 10(-5) M CBX in diabetic (20%) and in control (17%) hearts. Action potential durations (APDs), recorded on the epicardial surface of the left ventricle, were prolonged in paced (6 Hz) diabetic compared to control hearts. Perfusion of hearts with CBX caused further prolongation of APDs and to a greater extent in control compared to diabetic heart. Percentage prolongation at 70% from the peak of the action potential amplitude after CBX was 18% in diabetic compared to 48% in control heart. CBX had no significant effect on resting cell length or amplitude of ventricular myocyte shortening in diabetic or control rats. However, resting fura-2 ratio (indicator for intracellular Ca(2+) concentration) and amplitude of the Ca(2+) transient were significantly (P < 0.05) reduced by CBX in diabetic rats but not in controls. In conclusion the larger effects of CBX on APD in control ventricle and the normalizing effects of CBX on intracellular Ca(2+) in ventricular myocytes from diabetic rat suggest that there may be alterations in gap junction electrophysiology in STZ-induced diabetic rat heart.

Action Potentials↗
PubMed2005

The progressive effects of a fat enriched diet on ventricular myocyte contraction and intracellular Ca2+ in the C57BL/6J mouse.

The C57BL/6J mouse has a genetic susceptibility to develop diabetes when fed with a high-fat, high-sucrose diet. The general characteristics of diet-induced diabetes in this model include progressive development of hyperinsulinaemia, hyperglycaemia, insulin resistance and obesity, features that are frequently observed in the clinical setting. This study investigated the progressive effects of a fat enriched (FE) diet on contraction and intracellular Ca2+ in ventricular myocytes from the C57BL/6J mouse. The characteristics of the mice fed with the FE diet compared to mice receiving control diet included progressive increase in the rate of body weight gain, increased fasting blood glucose and time-dependent differences in the disposal of blood glucose after a glucose challenge. The ultrastructure of cardiac myocytes and associated capillaries did not show any gross morphological alteration after 27 weeks of FE diet compared to controls. At 5 months the resting cell length (RCL) and the kinetics of shortening were not significantly altered in ventricular myocytes from mice receiving the FE diet compared to age-matched controls. At 5 and at 7 months the amplitude of shortening was increased in myocytes receiving the FED diet compared to controls. At 7 months the time to half (THALF) relaxation of myocyte contraction was shortened in myocytes from mice receiving the FE diet compared to controls. Mean THALF relaxation in myocytes from mice fed the FE diet was 32.0 +/- 1.4 ms (n = 23) compared to 40.2 +/- 2.0 ms (n = 27) in controls. Neither resting intracellular Ca+ nor the kinetics or amplitude of the Ca2+ transient were altered by FE diet. Differences in myofilament sensitivity to Ca2+ might underlie the changes in contractility.

Animals↗
PubMed2005

Anorectal anomalies in adult females corrected by posterior sagittal anorectoplasty.

Posterior sagittal anorectoplasty (PSARP) is preferred by most pediatric surgeon and intermediate types of anorectal anomalies (ARA) in infants. In this report, we describe two girls who presented in their late teens with ARA and were treated by PSARP. Prior to this report, only two adult females with congenital rectovaginal fistulae treated by PSARP have been reported. Megarectum is a feature in late presentation of ARA and requires rectal tapering during PSARP. The functional outcome in late presentation of ARA is discussed.

Adolescent↗
PubMed2004

Effects of halothane on contraction and intracellular calcium in ventricular myocytes from streptozotocin-induced diabetic rats.

BACKGROUND: Some of the cellular targets affected by volatile anaesthetics (e.g. halothane) which contribute to the negative inotropic effects of these agents are also affected during the progression of diabetic cardiomyopathy. A previous report suggested that halothane inhibited contraction to a lesser extent in papillary muscle from diabetic animals and so the aim of this study was to investigate possible mechanisms underlying this effect. METHODS: Contractility and cytosolic calcium ion (Ca(2+)) transients were measured (fura-2) in ventricular myocytes isolated from control and streptozotocin (STZ)-induced diabetic rats in the absence and presence of halothane 0.6 mmol litre(-1) at 1 Hz stimulation. Sarcoplasmic reticulum (SR) Ca(2+) content was assessed by rapid application of caffeine. All experiments were carried out at 36-37 degrees C. RESULTS: The amplitude of shortening, the electrically evoked Ca(2+) transient, SR Ca(2+) content and myofilament Ca(2+) sensitivity, though not altered by STZ treatment, were significantly reduced by halothane to a similar extent in control and STZ myocytes. The time course of contraction and Ca(2+) transient were prolonged in myocytes from STZ-treated rats compared with controls but this was not altered further by halothane. STZ treatment appeared to reduce Ca(2+) efflux from the cell, an effect reversed by halothane. CONCLUSIONS: In contrast to a previous report, we could find no evidence of amelioration of the negative inotropic effect of halothane in myocytes from the STZ-induced diabetic rat. Contractility, the cytosolic Ca(2+) transient, SR Ca(2+) content and myofilament Ca(2+) sensitivity were qualitatively similar in control and STZ myocytes and were all depressed to the same extent by halothane.

Anesthetics, Inhalation↗
PubMed2004

Glucose and electrolyte supplementation of drinking water improve the immune responses of poults with inanition.

Enteric disorders predispose poultry to malnutrition. The objectives of this paper were 1) to simulate the inanition of poult enteritis mortality syndrome by restricting feed intake and 2) to develop a drinking water supplement that supports the immune functions of poults with inanition. Poults were restricted to 14 g of feed/d for 7 d beginning at 14 d of age then fed ad libitum until 36 d (recovery). The control was fed ad libitum. During the feed-restriction period, duplicate groups of 6 poults received 1 of 5 drinking water treatments: 1) restricted feed, unsupplemented water; 2) restricted feed + electrolytes (RE); 3) RE + glucose + citric acid (REGC); 4) REGC + betaine (REGCB); or 5) REGCB + zinc-methionine (REGCBZ). Immunological functions were assessed by inoculating poults with SRBC and B. abortus (BA) antigen at 15, 22, and 29 d of age. Antibody (Ab) titers were determined 7 d later for primary, secondary, and recovery responses. The primary and secondary total Ab titers to SRBC for restricted feed were 4.71 and 6.16 log3, which where lower (P < 0.05) than for controls (8.00 and 9.66 log3) and the other treatments. The recovery Ab titer for controls was 10.7, significantly higher than restricted feed (8.71) and RE (8.10) groups but not different from other treatments. The primary total Ab responses to BA were significantly lower in the restricted feed and RE groups as compared with the control and other treatments. Although feed restriction of poults to maintenance reduces the humoral immune responses, these responses can be significantly improved by drinking water containing electrolytes and especially sources of energy such as glucose and citric acid.

Animals↗
PubMed2004

Response of turkey poults to soybean lectin levels typically encountered in commercial diets. 1. Effect on growth and nutrient digestibility.

Lectins are known to bind to the intestinal brush border membrane and induce antinutritional effects such as disruption of the brush border membrane (BBM) and reduced nutrient digestibility in laboratory rodents. Because soybean lectin (SBL) is usually present in poult starter diets, 2 similar experiments with starting turkey poults were conducted to investigate the effects of purified SBL on growth performance and nutrient digestibility. Experimental diets were a corn starch-casein based control (lectin-free) semipurified diet (PD), semipurified diets containing 0.024 or 0.048% soybean lectin (PDL, PDH), and a corn-soybean meal diet (SBD). Experimental diets were fed from hatch to 14 d. Antibodies specific for soybean lectin were detected in the serum of poults fed the PDL and PDH diets, implying that the SBL in these diets remained active in the digestive tract. Poults fed the control PD or SBD grew equally well. The 0.024% SBL level in PDL had no significant detrimental effect on any parameters assessed in the 2 experiments. In contrast, the 0.048% SBL level in the PDH gave inconsistent results for feed efficiency (FE) and brush border enzyme levels. For instance, on d 6 in experiment 2, poults fed the PDH had poorer FE (P < 0.05) compared with the control PD treatment, but had similar FE to poults fed the PD in experiment 1. In conclusion, SBL present at levels up to 0.024% of the diet would not cause antinutritional effect in turkey poults up to 2 wk of age.

Animals↗
PubMed2003

Growth, livability, and feed conversion of 1957 versus 2001 broilers when fed representative 1957 and 2001 broiler diets.

Body weight, feed consumption, and mortality were measured in the 1957 Athens-Canadian Randombred Control (ACRBC) strain and in the 2001 Ross 308 strain of broilers when fed representative 1957 and 2001 diets. The dietary regimens were chosen to be representative of those used in the industry in 1957 vs. 2001. The 1957 diets were fed as mash, the 2001 starter was as crumbles, and the grower and finisher diets were pellets. Feed consumption and BW were recorded at 21, 42, 56, 70, and 84 d of age to cover the two broiler strains normal span of marketing ages. Mortality was low, and the mortality of the ACRBC was approximately half that of the modem strain. Average BW for the ACRBC on the 1957 diets were 176, 539,809, 1,117, and 1,430 g vs. 743, 2,672, 3,946, 4,808, and 5,520 g for the Ross 308 on the 2001 diets at 21, 42, 56, 70, and 84 d of age, respectively. The 42-d feed conversion (FC) on the 2001 and 1957 feeds for the Ross 308 were 1.62 and 1.92 with average BW of 2,672 and 2,126 g and for the ACRBC were 2.14 and 2.34 with average BW of 578 and 539 g, respectively. The Ross 308 broiler on the 2001 feed was estimated to have reached 1,815 g BW at 32 d of age with a FC of 1.47, whereas the ACRBC on the 1957 feed would not have reached that BW until 101 d of age with a FC of 4.42.

Aging↗
PubMed2003

Carcass composition and yield of 1957 versus 2001 broilers when fed representative 1957 and 2001 broiler diets.

The yield of carcass parts as well as levels of carcass fat, moisture, and ash were measured in the 1957 Athens-Canadian Randombred Control (ACRBC) and in the Ross 308 commercial broiler, when fed diets that were representative of those being fed during 1957 and 2001. The Ross 308 was used to represent 2001 commercial broilers. Comparisons of carcass weights of the Ross 308 on the 2001 diet versus the ACRBC on the 1957 diet showed they were 6.0, 5.9, 5.2, and 4.6 times heavier than the ACRBC at 43, 57, 71, and 85 d of age, respectively. Yields of hot carcass without giblets (fat pad included) were 12.3, 13.6, 12.2, and 11.1 percentage points higher for the Ross 308 than for the ACRBC at those ages. The yields of total breast meat for the Ross 308 were 20.0, 21.3, 21.9, and 22.2% and were 8.4, 9.9, 10.3, and 9.8 percentage points higher than for the ACRBC at those ages. Yields of saddle and legs for the Ross 308 broiler were approximately 31 to 32% over the four ages and were about 1.5 to 2% higher than for the ACRBC at the different ages. The Ross 308 averaged 13.7, 15.0, 18.6, and 18.5% whole carcass fat versus 8.5, 10.6, 12.7, and 14.0% for the ACRBC at the four ages. In conjunction with previous studies, the current data show that yield of broiler carcass parts has continued to increase over time and that genetics has been the major contributor to changes in yield.

Adipose Tissue↗
PubMed2003

A comparison of the immune response of a 2001 commercial broiler with a 1957 randombred broiler strain when fed representative 1957 and 2001 broiler diets.

Immunocompetence of the 2001 Ross 308 broiler strain and the 1957 Athens Canadian Randombred Control (ACRBC) strain was compared when they were given diets representative of those that were being used in 1957 and 2001. Antibody response against SRBC, in vivo lymphoproliferation against Phytohemagglutinin-P (PHA-P), and inflammatory and phagocytic responses of the macrophages were measured. The Ross 308 strain on the 2001 diet had higher BW at 24 d of age (P = 0.0001), whereas the ACRBC had greater lymphoid organ weights (except thymus) relative to BW (P < or = 0.003). The ACRBC strain showed greater antibody responses against SRBC than the 2001 Ross 308 birds for much of the trial (P < or = 0.0362). However, the Ross 308 broilers had greater PHA-P-induced toe-web swelling response (P < or = 0.0129). Inflammatory exudate cell numbers were higher in the Ross 308 broilers than in the ACRBC birds (P = 0.0261). The percentage of macrophages that phagocytized SRBC was comparable between the two strains, but the number of SRBC phagocytized by individual macrophages was higher (P = 0.0122) in the Ross 308 broiler than in the ACRBC chickens. Nitrite production by macrophages following lipopolysacharide stimulation was comparable between the two strains. Interactions of diet, strain, and sex were inconsistent among all parameters tested. In conclusion, the current study suggested that genetic selection for improved broiler performance has resulted in a decrease in the adaptive arm of the immune response but an increase in the cell-mediated and inflammatory responses.

Animal Feed↗
PubMed2003

Avian macrophage and immune response: an overview.

Macrophages belong to the mononuclear phagocytic system lineage. This cell type is unique in that it is a crucial player in both the innate and adaptive immune responses. The material described in this overview is a brief description of what I presented as a World's Poultry Science Association-sponsored lecture at the annual meetings of the Poultry Science Association in 2002. Therefore, I have not attempted to present an up-to-date review of literature on this topic. Rather, I have summarized some salient research accomplishments made by our research group over the years in the area of avian macrophage biology and function.

Animal Nutritional Physiological Phenomena↗
PubMed2003

Effects of organic forms of zinc on growth performance, tissue zinc distribution, and immune response of weanling pigs.

This study was conducted to determine the effect of zinc level and source on growth performance, tissue Zn concentrations, intracellular distribution of Zn, and immune response in weanling pigs. Ninety-six 3-wk-old crossbred weanling pigs (BW = 6.45 +/- 0.17 kg) were assigned to one of six dietary treatments (four pigs per pen, four replicates per treatment) based on weight and litter origin. Treatments consisted of the following: 1) a corn-soybean meal-whey diet (1.2% lysine) with a basal level of 80 ppm of supplemental Zn from ZnSO4 (control; contained 104 ppm total Zn); 2) control + 80 ppm added Zn from ZnSO4; 3) control + 80 ppm added Zn from Zn methionine (ZnMet); 4) control + 80 ppm added Zn from Zn lysine (ZnLys); 5) control + 40 ppm added Zn from ZnMet and 40 ppm added Zn from ZnLys (ZnML); and 6) control + 160 ppm added Zn from ZnSO4. Zinc supplementation of the control diet had no effect on ADG or ADFI. Gain efficiency was less (P < 0.05) for pigs fed 80 ppm of Zn from ZnSO4 than for control pigs and pigs fed 160 ppm of Zn from ZnSO4. Organ weights, Zn concentration, and intracellular distribution of Zn in the liver, pancreas, and spleen were not affected (P = 0.12) by Zn level or source. Skin thickness response to phytohemagglutinin (PHA) was not affected (P = 0.53) by dietary treatment. Lymphocyte proliferation in response to PHA was greater (P < 0.05) in pigs fed ZnLys than in pigs fed the control diet or the ZnML diet; however, when pokeweed mitogen was used, lymphocyte proliferation was greatest (P < 0.05) in pigs fed the ZnMet diet than pigs fed the control, ZnLys, ZnML, or 160 ppm ZnSO4 diets. Antibody response to sheep red blood cells was not affected by dietary treatments. Supplementation of 80 ppm of Zn from ZnSO4 or ZnMet and 160 ppm of Zn from ZnSO4 decreased (P < 0.05) the antibody response to ovalbumin on d 7 compared with control pigs, but not on d 14. Phagocytic capability of peritoneal exudate cells was increased (P < 0.05) when 160 ppm of Zn from ZnSO4 was supplemented to the diet. The number of red blood cells ingested per phagocytic cell was increased (P < 0.05) in pigs fed the diet supplemented with a combination of ZnMet and ZnLys and the diet with 160 ppm of Zn from ZnSO4. Results suggest that the level of Zn recommended by NRC for weanling pigs was sufficient for optimal growth performance and immune responses, although macrophage function may be enhanced at greater levels of Zn. Source of Zn did not alter these measurements.

Animal Nutritional Physiological Phenomena↗
PubMed2002

Involvement of lipopolysaccharide related receptors and nuclear factor kappa B in differential expression of inducible nitric oxide synthase in chicken macrophages from different genetic backgrounds.

Macrophages from Cornell K-strain chickens (B(15)B(15)) are hyper and from GB2 chickens (B(6)B(6)) are hypo-responders to LPS-mediated inducible NOS (iNOS) expression and activity. The molecular mechanism(s) responsible for this differential expression is not yet fully understood. We have previously reported that macrophages from K (iNOS hyper-responder) and GB2 (iNOS hypo-responder) chickens differ in constitutive expression of TLR4 but not in CD14 molecules. The objectives of the current study was to determine if the iNOS differences between K and GB2 macrophages are possibly due to differential expression of LPS-induced TLR4, CD14 and/or nuclear factor kappa B (NF kappa B). The results showed that Sephadex-elicited, adherence purified K macrophages expressed more inducible TLR4 and CD14 receptors (P<0.05) at 6 and 12h post-LPS stimulation than GB2 macrophages as measured by flow cytometry. In addition, pre-incubation of macrophages from a transformed chicken macrophage cell line, MQ-NCSU, with 50 microg/ml anti-CD14 and anti-TLR4 antibodies significantly reduced where as pre-incubation with 100 microg/ml completely blocked LPS-mediated iNOS activity as measured by nitrite levels. Furthermore, the amount of nuclear bound NF kappa B was found to be significantly greater in K than in GB2 macrophages at 3 min post-LPS stimulation. This nuclear localization of NF kappa B as well as iNOS activity was completely inhibited by pretreatment of macrophages with 50 micro M MG132, a proteosome inhibitor, both in K and GB2 macrophages. Taken together, these findings suggest that a differential and perhaps more stronger LPS-mediated signaling via CD14, TLR4 and NF kappa B is responsible for the heightened iNOS gene induction in K-strain (hyper-responder) macrophages than in GB2 (hypo-responder) chickens.

Animals↗
PubMed2002

Effects of hyperosmotic shrinking on ventricular myocyte shortening and intracellular Ca(2+) in streptozotocin-induced diabetic rats.

Evidence exists for a specific diabetic cardiomyopathy independent of concurrent vascular disease. We tested the hypothesis that chronic hyperglycaemia found in streptozotocin- (STZ) induced diabetic rats leads to an altered response to and contractile effects of hyperosmotic shrinkage in ventricular myocytes. Analysis confirmed significant hyperglycaemia and revealed significant blood hyperosmolarity in STZ-treated rats. Myocyte volume changes, shortening and intracellular Ca(2+) ([Ca(2+)](i)) transients were measured in cells superfused with normal Tyrode (NT, 300 mmol/kg) and then hyperosmotic Tyrode (HT, 440 mmol/kg) at 35-36 degrees C. Shrinking significantly reduced the amplitude of shortening, whilst the [Ca(2+)](i) transient was significantly increased. The time course of both shortening and the [Ca(2+)](i) transient were prolonged in myocytes from STZ-treated compared to control rats. Time to peak shortening was 130.3 ms in STZ compared to 100.2 ms in control myocytes. Time to peak [Ca(2+)](i) transient was 70.8 ms in STZ compared to 44.6 ms in control myocytes and the time from peak to half recovery was 191.0 ms in STZ compared to 169.1 ms in control myocytes. Fractional SR Ca(2+) release, assessed by the application of caffeine, was increased by shrinking. However, the effects of raised extracellular osmolarity on volume changes, contractility and [Ca(2+)](i) were not altered by the chronic hyperglycaemia found in STZ-treated rats.

Animals↗
PubMed2002

Cardiac microtubules are more resistant to chemical depolymerisation in streptozotocin-induced diabetes in the rat.

Evidence exists for a specific diabetic cardiomyopathy independent of concurrent vascular disease. Our aim was to test the hypothesis that a change in the microtubular cytoskeleton may contribute to cardiac dysfunction in type-1 diabetes. Resting sarcomere length and characteristics of unloaded shortening were measured in ventricular myocytes from rats 2 months after injection of streptozotocin (STZ). Microtubular density and organisation were assessed using immunofluorescence confocal microscopy and the effects of microtubule disruption by colchicine on shortening and microtubules were examined. Diabetic myocytes showed a significant reduction in resting sarcomere length and a 30% increase in time to peak shortening. The microtubule disruptor colchicine (10 micromol/l) had no effect on the amplitude or kinetics of shortening in myocytes from control or diabetic rats. Cardiac microtubular density and organisation were similar in control and diabetic animals, yet although colchicine significantly reduced microtubule density in control myocytes, microtubules in diabetic myocytes were resistant to its effects. These observations of an increase in microtubular stability in STZ-diabetes of 2 months duration imply a disruption to the normal balance between populations of dynamic and drug-stable microtubules. Such disruption has been observed in other pathological conditions and may contribute to diabetic cardiomyopathy.

Animals↗
PubMed2002

Calsequestrin expression and calcium binding is increased in streptozotocin-induced diabetic rat skeletal muscle though not in cardiac muscle.

Altered mechanisms of Ca2+ transport may underlie the contractile dysfunctions that have been frequently reported to occur in diabetic cardiac and skeletal muscle tissues. Calsequestrin, a high-capacity Ca2+-binding protein, is involved in the regulation of the excitation-contraction-relaxation cycle of both skeletal and cardiac muscle fibres. We have investigated the expression of calsequestrin and Ca2+ binding in cardiac and skeletal muscle from streptozotocin-induced diabetic rat. Immunoblotting of microsomal membranes from normal and streptozotocin-induced diabetic muscle revealed no significant changes in heart, but an increase in the relative abundance of calsequestrin and calsequestrin-like proteins in skeletal muscle. In analogy, the overall Ca2+-binding capacity of sarcoplasmic reticulum vesicles from diabetic skeletal muscle was drastically increased. The expression of fast muscle marker proteins was not affected, indicating that no relevant fibre transformation occurred in streptozotocin-treated rat muscles. The up-regulation of the high-capacity Ca2+-binding element calsequestrin might represent a compensatory mechanism of diabetic skeletal muscle. An increased Ca2+-buffering capacity of the sarcoplasmic reticulum lumen might counteract elevated cytosolic Ca2+ levels in diabetes thereby preventing Ca2+-dependent myo-necrosis.

Animals↗
PubMed2002

Differential expression of inducible nitric oxide synthase is associated with differential Toll-like receptor-4 expression in chicken macrophages from different genetic backgrounds.

The purpose of this study was to examine iNOS gene expression and activity in macrophages from different chicken genetic lines against various bacterial LPS. Furthermore, the possible involvement of surface LPS receptors as candidates for differential iNOS gene induction in these genetic lines of chicken was also examined. Sephadex-elicited abdominal macrophages (1 x 10(6)) as well as iNOS hyper-responder macrophages from a transformed chicken macrophage cell line, MQ-NCSU, were exposed to 5 microg/ml LPS from E. coli, Shigella flexneri, Serratia marcensces, and Salmonella typhimurium. Nitrite levels were quantitated in the culture supernatant fractions of macrophages after 24h by the Griess method. The results showed that macrophages from K-strain (B(15)B(15)) (range from two separate trials: 31-89 microM) and MQ-NCSU (22-81 microM) were high responders whereas macrophages from both GB1 (B(13)B(13)) (15-38 microM) and GB2 (B(6)B(6)) (7-15 microM) chickens were low responders against all LPSs used. Northern blot analysis revealed that K-strain macrophages expressed higher intensity of 4.5Kb iNOS mRNA (iNOS/beta-actin ratio) than macrophages from GB2 regardless of the LPS source. To elucidate possible molecular mechanism(s) involved in iNOS gene expression in these two strains of chickens, the constitutive expression of LPS-related macrophage cell surface receptors, CD14, Toll-like receptor-2 (TLR2), and Toll-like receptor-4 (TLR4), was examined via flow cytometry using anti-human CD14, TLR2 and TLR4 antibodies. CD14 surface expression and intensity was not different between macrophages from K-strain or GB2 chickens. In contrast, while the overall percentage of TLR4-positive macrophages was the same (K-strain, trial 1=92%, trial 2=62%; GB2, trial 1=91%, trial 2=64%), the mean fluorescence intensity (MFI), an indicator of receptor number, was significantly higher (P=0.05) in K-strain macrophages (MFI: trial 1=145; trial 2=131) than GB2 macrophages (MFI: trial 1=101; trial 2=98). Furthermore, TLR2 (a previously thought candidate as LPS signaling molecule) positive cell numbers were higher in K-strain than the GB2 macrophages in one of the two trials with no difference in the intensity of TLR2 expression in either trial. These findings suggest that the observed differences in iNOS expression and activity among the K-strain (hyper-responder) and GB2 (hypo-responder) chickens are, at least in part, due to differential expression of TLR4 (an LPS signaling molecule), leading to more intense LPS-mediated activation of K-macrophages.

Animals↗