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H M Hassan

Publications and source records attributed to H M Hassan.

At least 19 recordsLinked to original sources
PubMed2006

Molecular identity of the electrophoretic pattern and the major cross-reacting immunogens of Toxoplasma gondii (RH strain) and Neospora caninum.

The complex electrophoretic profile of the antigenic components of Toxoplasma gondii and Neospora caninum was studied. T. gondii (RH strain) trophozoite's antigens were resolved by gel electrophoresis under denaturating condition. Resolved polypeptides were tested by immunoblotting against hyper-immune serum prepared in Boscat rabbits. Immunoblot analysis revealed 6 reactive bands, which are 158, 111, 102, 86, 55 and 33 kDa, out of 10 antigenic bands of the parasite. Concerning N. caninum trophozoite's antigens, immunoblot analysis revealed 5 reactive bands, which are 159, 119, 106, 97 & 39 kDa, out of 8 antigenic bands of the parasite. Cross reactivity trials between the 2 parasites explore 3 cross-reactive bands, indicating high antigenic similarity in between.

Animals↗
PubMed2003

Effect of malic acid on the growth kinetics of Lactobacillus plantarum.

The fermentation kinetics of Lactobacillus plantarum were studied in a specially designed broth formulated from commercially available, dehydrated components (yeast extract, trypticase, ammonium sulfate) in batch and continuous culture. During batch growth in the absence of malic acid, the specific growth rate was 0.20 h(-1). Malic acid in the medium, at 2 mM or 10 mM, increased the specific growth rate of L. plantarum to 0.34 h(-1). An increase in the maximum cell yield due to malic acid also was observed. Malic acid in the medium (12 mM) reduced the non-growth-associated (maintenance energy) coefficient and increased the biomass yield in continuous culture, based on calculations from the Luedeking and Piret model. The biomass yield coefficient was estimated as 27.4 mg or 34.3 mg cells mmol(-1) hexose in the absence or presence of malic acid, respectively. The maintenance coefficient was estimated as 3.5 mmol or 1.5 mmol hexose mg(-1) cell h(-1) in the absence or presence of malic acid. These results clearly demonstrate the energy-sparing effect of malic acid on the growth- and non-growth-associated energy requirements for L. plantarum. The quantitative energy-sparing effect of malic acid on L. plantarum has heretofore not been reported, to our knowledge.

Cucumis sativus↗
PubMed2003

RpoS-dependent stress response and exoenzyme production in Vibrio vulnificus.

Vibrio vulnificus is an estuarine bacterium capable of causing rapidly fatal infections through both ingestion and wound infection. Like other opportunistic pathogens, V. vulnificus must adapt to potentially stressful environmental changes while living freely in seawater, upon colonization of the oyster gut, and upon infection of such diverse hosts as humans and eels. In order to begin to understand the ability of V. vulnificus to respond to such stresses, we examined the role of the alternate sigma factor RpoS, which is important in stress response and virulence in many pathogens. An rpoS mutant of V. vulnificus strain C7184o was constructed by homologous recombination. The mutant strain exhibited a decreased ability to survive diverse environmental stresses, including exposure to hydrogen peroxide, hyperosmolarity, and acidic conditions. The most striking difference was a high sensitivity of the mutant to hydrogen peroxide. Albuminase, caseinase, and elastase activity were detected in the wild type but not in the mutant strain, and an additional two hydrolytic activities (collagenase and gelatinase) were reduced in the mutant strain compared to the wild type. Additionally, the motility of the rpoS mutant was severely diminished. Overall, these studies suggest that rpoS in V. vulnificus is important for adaptation to environmental changes and may have a role in virulence.

Culture Media↗
PubMed2001

Effects of beta-carotene, selenium and vitamin A on in vitro polymorphonuclear leukocytic activity in peripartal buffalo (Bubalus bubalus).

The effect of different concentrations of three antioxidans on phagocytic and kill activities of blood polymorphonuclear leukocytes (PMN) isolated from buffaloes during the peripartum period (4 weeks before to 7 weeks after parturition) was investigated in this study. Two concentrations of beta-carotene and vitamin A (10(-6) and 10(-5) M) and one concentration of Se (10(-9) M) were used. Phagocytic activity of PMN treated with beta-carotene (10(-6)M) significantly enhanced (P < 0.05) after parturition (Week 0 until Week 3), whereas the kill activity of the same cells significantly (P < 0.05) increased before and after parturition (at Weeks -4, -3, -2, 0, 1, 2 and 3). The concentration of beta-carotene (10(-5) M) enhanced phagocytosis of PMN only at Weeks 0 and 1 and kill activity at Weeks -4, -3, -2, 0, and 1. Selenium (10(-9)M) significantly (P < 0.05) enhanced phagocytic activity of PMN starting from parturition (Week 0) until Week 3 postpartum. Kill activity increased significantly both before (Weeks -4, -3 and -2) and after (Weeks 0, 1, 2, 3 and 4) parturition. Vitamin A (10(-6) M) significantly enhanced phagocytic activity of PMN at Weeks 0, 1, and 2, whereas, the concentration of beta-carotene (10(-5) M) increased phagocytic activity only at Week 0. Kill activity of PMN increased significantly (P < 0.05) at Weeks -1 and 0 (10(-6)M). These results demonstrate that beta-carotene and selenium significantly enhanced phagocytic and kill activities of PMN isolated from buffaloes around parturition in vitro. Vitamin A enhanced phagocytosis and kill activities but not to the same extent as beta-carotene and selenium. Apparently, the in vitro killing activity of PMN is a distinctive function from phagocytosis and both activities may be enhanced by the use of essential nutrients, especially during the peripartum period. Moreover, beta-carotene is more effective as an antioxidant than vitamin A in enhancing the activities of phagocytic cells.

Animals↗
PubMed2001

Immune regulation of ovarian function in buffaloes (Bubalus bubalus).

We studied the infiltration of different subsets of immune system cells in the ovarian parenchyma of Egyptian buffaloes during follicular and luteal phases of the estrous cycle. All subsets of leukocytes infiltrated significantly more into corpora lutea (CL) than into Graafian follicles (GF) (P < 0.01) except for plasma cells that were abundant in the GF but not observed in the CL. The number of macrophages, lymphocytes, neutrophils and eosinophils were significantly greater in mature CL than in corpora hemorrhagica (CH) or regressing CL. Moreover, the regressing CL showed significantly more macrophages, lymphocytes and neutrophils than the CH. Large antral follicles were infiltrated with larger number of leukocytes than growing preantral atretic follicles. Macrophages and neutrophils observed in large antral follicles were significantly more abundant in the theca externa than the theca interna (P < 0.01). Only plasma cells were significantly greater in number in the theca intema (P < 0.01). Leukocytes infiltrated significantly more into large mature follicles than large, growing, preantral atretic follicles (P < 0.01). Results of this study reveal the calling of leukocytes in a significant numbers inside the ovarian tissue of buffaloes around the time of ovulation and at luteolysis. It is possible that leukocytes with their powerful bioactive cytokines (IL-1, TNFalpha, GM-CSF, and INF-gamma) may assist in ovarian functions such as ovulation and luteolysis.

Animals↗
PubMed2001

Characterization of the iron superoxide dismutase gene of Azotobacter vinelandii: sodB may be essential for viability.

Azotobacter vinelandii contains two superoxide dismutases (SODs), a cytoplasmic iron-containing enzyme (FeSOD), and a periplasmic copper/zinc-containing enzyme (CuZnSOD). In this study, the FeSOD was found to be constitutive, while the activity of CuZnSOD increased as the culture entered the stationary phase. Total SOD (units/mg protein) in stationary phase cells grown under nitrogen-fixing conditions was not significantly different from those grown under non-nitrogen-fixing conditions. The gene encoding FeSOD (sodB) was isolated from an A. vinelandii cosmid library. A 1-kb fragment containing the coding region and 400 base pairs of upstream sequence was cloned and sequenced. The nucleotide sequence and the deduced amino acid sequence had a high degree of homology with other bacterial FeSODs, particularly with P. aeruginosa. Attempts to construct a sodB mutant by recombination of a sodB::kan insertion mutation into the multicopy chromosome of A. vinelandii were unsuccessful even in the presence of SOD mimics or nutritional supplements. These results suggest that FeSOD may be essential for the growth and survival of A. vinelandii, and that the periplasmic CuZnSOD cannot replace the function of FeSOD.

Amino Acid Sequence↗
PubMed2001

An epidemiological study of neonatal necrotizing enterocolitis.

OBJECTIVE: To study epidemiology including various risk factors incorporated in neonatal necrotizing enterocolitis in Kashmir. METHODS: A retrospective hospital based study on 3235 neonates admitted in Neonatal Intensive Care Unit of Sheri-Kashmir Institute, were evaluated. Forty two were diagnosed as cases of Neonatal Necrotizing Enterocolitis on the basis of various clinical and radiological parameters and grouped in 3 stages as per modified Bell's classification. The case records of these 42 babies and 303 of the control group were reviewed for the purported risk factors and recorded on pretested proforma and finally statistically analyzed. RESULTS: Over a period of 10 years, we documented necrotizing enterocolitis in 42 neonates, with an incidence of 1% of all Neonatal Intensive Care Unit admissions and 1% of all live births. Eighty one percent were less than 2000 gms and 76% less than 36 weeks of gestation. Twenty four percent had stage I disease, 33% had stage II, and 43% babies had stage III disease. Multiple risk factors were present in these babies, with significant differences among Necrotizing Enterocolitis and the control group of patients, particularly hypothermia (P < 0.001), respiratory distress (P < 0.05), polycythemia (P < 0.001) acidosis (P < 0.01), sepsis (P < 0.001), enteral feeding and asphyxia (P < 0.001). Of the 59 babies (< 2000 gms) with hypothermia (< 35 degrees C), 39% developed Necrotizing Enterocolitis, compared to 4% babies (11/278), who did not have hypothermia, statistically a significant finding. Mean birth weight and gestational age were lower than in control group (P < 0.05). The age of presentation was 5.2 +/- 4.0 days and majority (81%) presented during first week of life, most severe cases presenting earlier than the mild cases. Severity of Necrotizing Enterocolitis as per modified Bell's classification and mortality was inversely related to birth weight and gestational age. One hundred percent mortality was noted in the babies, with birth weight less than 1000 gms and gestational age less than 28 weeks. The overall mortality was 45%, for stage I, 20%; for stage II, 36% and 67% for stage III. Necrotizing Enterocolitis cases accounted for maximum mortality in Neonatal Intensive Care Unit than in control group (P < 0.001). CONCLUSION: Recognition of factors such as prematurity, low birth weight, hypothermia, asphyxia and their timely prevention would help in reducing morbidity and mortality due to Necrotizing Enterocolitis.

Birth Weight↗
PubMed1999

Isolation of immunologically active uterine luminal proteins associated with follicular and luteal phases of the ovary in buffalo (Bubalus bubalus).

Uterine luminal proteins (ULP) collected from the genital tract of buffalo during the follicular (Group F) and luteal (Group L) phases of the estrous cycle were chromatographed using sephacryl S-200 gel. Five peaks were detected in each group. Different protein concentrations (10 to 200 microg) from Peaks I and V in each group were examined for immunological activity on polymorph nuclear leukocytic cells (PMNL) in vitro. All concentrations except 10 microg of ULP Peak I (< or = 250 kDa) in Group F enhanced phagocytic activity of PMNL. Peak V (56 kDa) in the same group enhanced phagocytic activity of PMNL only at low protein concentrations (10, 20 and 40 microg protein), while at greater concentrations (80, 150 and 200 microg protein) PMNL activity was suppressed. On the other hand, all protein concentrations from Peak 1 (> or = 250 kDa) in Group L suppressed PMNL activity in a dose-dependent manner. Proteins from Peak V (31 kDa) in Group L suppressed PMNL phagocytic activity at all concentrations but not to the same extent as in Peak I. Electrophoretic analysis of Peaks I and V in both groups revealed only 3 detectable protein bands (subunits) in Peak I and 1 detectable subunit in Peak V. Several additional proteins were probably not detected. The molecular weights of the detected subunits in Peaks I and V in Group F were greater than those in Group L as indicated by SDS-PAGE analysis. The results of this study show that ULP collected from buffalo possessed proteins that modulated phagocytic activity of PMNL in vitro. Proteins collected during the follicular phase, especially Peak I, enhanced phagocytic activity of the PMNL, whereas those collected during the luteal phase (Peaks I and V) suppressed activity. Changes in the molecular weights of ULP detected in this experiment may be related to the changes in phagocytic activity of PMNL tested in vitro.

Animals↗
PubMed1999

The effect of nitric oxide on platelets when delivered to the cardiopulmonary bypass circuit.

UNLABELLED: Nitric oxide (NO) decreases platelet adhesion to foreign surfaces in the in vitro models of cardiopulmonary bypass (CPB). We hypothesized that NO, delivered into the membrane oxygenator (MO), would exert a platelet-sparing effect after CPB. Forty-seven patients scheduled for coronary artery surgery were randomized to either a NO group, in which NO (100 ppm) was delivered into the MO, or a control group, in which CPB was conducted without NO. Platelet numbers, platelet aggregation response to 2.5-20 microM adenosine diphosphate, and beta-thromboglobulin levels were measured after induction of anesthesia, after 1 h on CPB and 2 h after the end of CPB. Met-hemoglobin levels were measured during CPB. The amount of blood products administered and chest tube drainage were measured in the first postoperative 18 h. NO delivered into the MO for up to 180 min did not increase met-hemoglobin levels above 4%. NO inhibited the platelet aggregation response to 2.5 microM ADP during CPB, otherwise NO had no other detectable effect on the aggregation responses or the levels of beta-thromboglobulin. Platelet numbers were not significantly altered by NO. NO did not alter the use of blood products or chest tube drainage. In conclusion, this study suggests that NO delivered into the MO of the CPB circuit does not significantly alter platelet aggregation and numbers, and does not affect bleeding. IMPLICATIONS: Nitric oxide affects platelet function. We demonstrated that nitric oxide delivered into the gas inflow of the cardiopulmonary bypass circuit membrane oxygenator does not significantly alter platelet numbers or function.

Adenosine Diphosphate↗
PubMed1999

Long-term effect of growth hormone (GH) treatment on body composition in children with GH deficiency.

OBJECTIVE: It is important for GH-deficient children to treat abnormal body composition associated with a metabolic consequence, not only short stature. In this study we evaluated long-term effects of GH therapy on body composition in GH-deficient boys and girls. SUBJECTS AND METHODS: Forty-nine subjects with GH deficiency, 35 boys and 14 girls, 6 to 14 years of age, were studied. All the subjects were treated for three years with recombinant human GH at a weekly dosage of 0.5 IU/kg by subcutaneous daily injection. Body composition was measured by bioelectrical impedance analysis (BIA 101, Spectrum II 287, RJL Systems, Detroit, Mich). RESULTS: Body fat (%) decreased significantly during the first three months of GH treatment. These values were maintained low thereafter in boys, in contrast to those which continued to tend upward in girls from the second year of the treatment. Lean body mass (kg) increased significantly with increasing extracellular water (kg) and body cell mass (kg) in both sexes during GH treatment. CONCLUSION: Our data demonstrate that GH can reduce body fat mass in GH-deficient boys and girls. The gender difference in changes in body fat with age during the course of this study is compatible with that observed in normal children. The rapid increase in extracellular water and the gradual increase in body cell mass both contributed to the steady increase in LBM during GH treatment.

Adipose Tissue↗
PubMed1998

Mechanism of regulation of 8-hydroxyguanine endonuclease by oxidative stress: roles of FNR, ArcA, and Fur.

We found previously that 8-hydroxyguanine (oh8Gua) endonuclease in E. coli is induced in response to oxidative stress in a fashion similar to the oxidative response of the Mn-superoxide dismutase (MnSOD). In this study, attempts were made to identify the genes involved in the co-regulation of E. coli endonuclease and MnSOD (sodA). oh8Gua nuclease is induced by molecular oxygen and a superoxide radical generator (paraquat) but not by H2O2, suggesting that the regulation of this endonuclease is dependent on SoxRS but independent of OxyR. This enzyme was induced by paraquat in all of the soxRS mutant strains used (soxR-, soxS- and soxRc), whereas glucose-6-phosphate dehydrogenase (a member of the soxRS regulon) showed the expected responses; therefore, this possibility was excluded. The presence of metal chelators in the growth medium caused the induction of this enzyme, and this induction was suppressed by the addition of Fe++. Consistent with this finding, this enzyme was expressed under anaerobiosis in all of the mutant strains of fnr in particular, as well as fur, arcA, and combinations thereof. These findings suggest that the oxidative regulation of oh8Gua endonuclease is under control of fnr, fur, and arcA, where fnr plays a predominant role. The multiple involvement of regulatory genes as well as co-regulation with antioxidant enzyme will enhance the efficiency of cellular growth and survival in the aerobic environment.

Bacterial Outer Membrane Proteins↗
PubMed1998

Long-term prospective study of body composition and lipid profiles during and after growth hormone (GH) treatment in children with GH deficiency: gender-specific metabolic effects.

GH has many effects on metabolism in addition to promoting growth. We studied changes in body composition and lipid profiles during and after GH treatment in 94 children with GH deficiency. Sixty-two subjects (46 boys and 16 girls) were evaluated at the beginning and during 36 months of GH treatment. The other 32 (21 boys and 11 girls) who had already been treated with GH were examined after the discontinuation of GH for a 6-month period. The height SD scores at the beginning and the discontinuation of GH treatment were -2.81 and -1.34 in boys and -3.14 and -1.38 in girls, respectively. The percent body fat (BF) significantly decreased from 16.5% to 11.7% in boys and from 16.7% to 11.6% in girls during the first 6 months of GH treatment (P < 0.01). BF subsequently remained constant in boys, but started to increase in girls from the 18th month of treatment. Lean body mass (kilograms) increased linearly throughout the treatment in both sexes (P < 0.01). Mean total cholesterol (TC) values decreased as a result of marked declines in low density lipoprotein cholesterol in both sexes, although statistical significance was detected only in boys (P < 0.01). High density lipoprotein cholesterol (HDLC) and apolipoprotein AI (Apo-AI) rapidly increased only in boys (P < 0.01). Triglyceride, Apo-AII, Apo-B, Apo-CII, Apo-CIII, Apo-E, and lipoprotein(a) showed no significant changes compared with baseline levels. Mean TC/HDLC and Apo-B/Apo-AI ratios decreased during treatment in both sexes, but the difference from baseline was significant only in boys (P < 0.01). After discontinuation of GH treatment, BF increased, and lean body mass decreased in boys (P < 0.01), whereas these variables did not change in girls. TC and low density lipoprotein cholesterol increased in boys within 6 months of discontinuing GH (P < 0.05). Other lipoproteins did not change in either sex, except for lipoprotein(a), which decreased significantly 6 months after the cessation of GH treatment in boys (P < 0.01). The mean TC/HDLC and Apo-B/Apo-AI ratios increased in boys slightly, but insignificantly. We concluded that GH treatment has beneficial effects on body composition and lipid profiles in both boys and girls with GH deficiency, although there are considerable gender differences. These beneficial effects of GH were reversed after the discontinuation of GH treatment, suggesting an important role of GH for GH-deficient children in the maintenance of normal metabolism even after the completion of linear growth.

Adolescent↗
PubMed1997

Characterization of superoxide dismutase in Streptococcus thermophilus.

Streptococcus thermophilus AO54 possesses a single manganese-containing superoxide dismutase (MnSOD). The enzyme was found to be insensitive to cyanide or to a modified H2O2 treatment. The enzyme is expressed in a growth-phase-dependent fashion, increasing three- to fourfold upon entry into stationary phase. The specific activity for MnSOD was the same under anaerobic or aerobic conditions and was not induced by the presence of paraquat under aerobic conditions.

Aerobiosis↗
PubMed1996

Body composition, atherogenic risk factors and apolipoproteins following growth hormone treatment.

We studied the change in atherogenic risk factors in 27 children, 21 boys and 6 girls, 6 to 14 years of age, with growth hormone deficiency during 12 months of growth hormone replacement therapy. Changes in body composition and lipid profile during growth hormone treatment were evaluated. The atherogenic index was calculated using the equation [(total cholesterol- high-density lipoprotein cholesterol)(apolipoprotein B)]/[(apolipoprotein AI)(high-density lipoprotein cholesterol)]. Body fat decreased (p < 0.01), associated with an increase in lean body mass (p < 0.01). Total cholesterol and high-density lipoprotein cholesterol showed no significant changes. The atherogenic index significantly decreased from 1.44 +/- 0.60 to 1.09 +/- 0.52 (p < 0.01) after 12 months. Apolipoproteins CII and CIII increased throughout the study period (p < 0.01). Lipoprotein(a) and apolipoproteins AI, B and B/AI ratio did not change significantly. In conclusion, growth hormone treatment improved body composition and reduced atherogenic risk factors in children with growth hormone deficiency.

Adolescent↗
PubMed1995

Binding of integration host factor (IHF) to the Escherichia coli sodA gene and its role in the regulation of a sodA-lacZ fusion gene.

We used the electrophoretic mobility-shift assay to reveal specific DNA-protein interactions between DNA fragments containing the sodA promoter and proteins present in Escherichia coli cell-free extracts. We have shown specific binding of several E. coli proteins to sodA promoter sequences and identified one of these proteins as the integration host factor (IHF). Mobility-shift experiments with cell-free extracts prepared from himA (IHF-negative) mutant strains lacked a specific DNA-protein band relative to shifts made with wild-type extracts. Several potential IHF-binding sites were identified in the sodA promoter region. Purified IHF was found to bind specifically to DNA fragments containing the sodA promoter. Further evidence presented suggests that IHF binds to multiple sites in the sodA promoter. We have also investigated the transcriptional regulation of sodA by monitoring the expression of a sodA-lacZ fusion gene in an IHF-negative E. coli strain under different growth conditions. Under aerobic conditions, a deletion in himA (IHF subunit alpha) resulted in a 60% increase in sodA expression, while having no effect on induction by paraquat. The same deletion in himA did not cause derepression of sodA-lacZ during anaerobic growth, but resulted in an increased response (about twofold) to the presence of 2,2'-dipyridyl compared to the isogenic wild-type strain.

2,2'-Dipyridyl↗
PubMed1994

The effects of fur on the transcriptional and post-transcriptional regulation of MnSOD gene (sodA) in Escherichia coli.

Earlier studies have shown that the Fur (ferric uptake regulation) protein acts as an anaerobic/aerobic repressor of MnSOD (sodA) expression. We found that the aerobic expression of sodA::lacZ fusion in a Fur- background to be threefold higher than in a Fur+ background. This effect of fur mutation was not seen in a strain harboring the sodA+ gene instead of the sodA::lacZ fusion. However, we observed a proportionate increase in the concentrations of sodA::lacZ and sodA+ mRNAs in response to a mutation in the fur gene. These data suggest that the formation of active MnSOD is dependent on a functional fur gene. Indeed, we found that in a fur mutant iron was incorporated into SodA in place of manganese, thus creating inactive and/or partially active forms of the enzyme (i.e., Fe2SodA and/or Mn,FeSodA, respectively), resulting in little or no increase in total MnSOD activity. Thus, Fur plays the role of a repressor at the transcriptional level, but it also plays an indirect role at the post-transcriptional level where it affects the maturation of SodA into a fully active enzyme, Mn2SodA (MnSOD).

Aerobiosis↗
PubMed1994

Stability of Escherichia coli sodA mRNA and identification of the transcriptional start site(s) under different environmental and oxidative stresses.

Manganese-containing superoxide dismutase (MnSOD-sodA) in Escherichia coli (E. coli) is regulated at the transcriptional level as observed in studies using both operon and gene fusions. In this paper we examine the regulation of sodA gene at the level of mRNA. We examine the effects of several aerobic inducing conditions (i.e., nalidixic acid, paraquat, or 2,2'-dipyridyl) on mRNA stability, transcription initiation, and translation. The half-life of sodA mRNA was found to be approximately 3-4 min, showing no differences in mRNA stability between induced and uninduced cells. We also found, by reverse transcriptase, that the second putative promoter is not functional under normal or stress conditions, and the amount of mRNA was found to be proportional to active MnSOD. Thus, these results indicate that under oxidative stress/inducing conditions, the increase in aerobic transcription of sodA occurs from only one transcription start site without affecting the stability of sodA mRNA. In addition, the 1:1 ratio found between increases in sodA mRNA and active MnSOD suggests that no translational regulation occurs aerobically.

2,2'-Dipyridyl↗