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1.
Sci Rep ; 14(1): 449, 2024 01 03.
Article in English | MEDLINE | ID: mdl-38172191

ABSTRACT

The coronavirus (COVID-19) pandemic has not only had a severe impact on global health but also poses a threat to the environment. This research aims to explore an innovative approach to address the issue of increased waste generated by the pandemic. Specifically, the study investigates the utilization of discarded face masks in combination with recycled concrete aggregate (RCA) and Silica Fume (SFM) in civil construction projects. The disposable face masks were processed by removing the ear loops and nose strips, and then cutting them into small fibers measuring 20 mm in length, 5 mm in width, and 0.46 mm in thickness, resulting in an aspect ratio of 24. Various proportions of SFM and RCA were incorporated into the concrete mix, with a focus on evaluating the compressive strength, split tensile strength, and durability of the resulting material. The findings indicate that the addition of SFM led to improvements in both compressive and split tensile strength, while no significant impact on durability was observed.


Subject(s)
Waste Management , Waste Management/methods , Silicon Dioxide , Masks , Construction Materials , Industrial Waste/analysis
3.
Protein Pept Lett ; 30(11): 900-912, 2023.
Article in English | MEDLINE | ID: mdl-37953619

ABSTRACT

Alzheimer's disease, a neurodegenerative disease, is a progressive and irreversible disease that has become a global challenge due to its increasing prevalence and absence of available potential therapies. Protein misfolding and aggregation are known to be the root of several protein neurodegenerative diseases, including Alzheimer's disease. Protein aggregation is a phenomenon where misfolded proteins accumulate and clump together intra-or extracellularly. This accumulation of misfolded amyloid proteins leads to the formation of plaquesin the neuronal cells, also known as amyloid ß plaques. The synthesis of amyloid ß plaques and tau protein aggregation are the hallmarks of Alzheimer's disease. Potential therapeutics must be developed in conjunction with an understanding of the possible root cause involving complex mechanisms. The development of therapeutics that can inhibit protein misfolding and aggregation, involved in the pathogenesis of Alzheimer's disease, could be one of the potential solutions to the disease.


Subject(s)
Alzheimer Disease , Neurodegenerative Diseases , Humans , Alzheimer Disease/metabolism , Amyloid beta-Peptides/metabolism , Protein Aggregates , tau Proteins/metabolism
4.
Biodegradation ; 2023 Nov 21.
Article in English | MEDLINE | ID: mdl-37987937

ABSTRACT

Composting is a process of microbial degradation of organic waste and is commonly applied for waste management. This is a slow process and requires a lot of land and human resources. The present study investigated mechanical augmentation with required microbial culture for composting municipal solid waste (MSW). Thirty isolates were subjected to 16S rDNA PCR amplification and gene sequencing. The isolates' sequencing from the compost samples was processed on BLASTn. Fourteen strains were identified for further experiments. The results divulge that Empedobacter (04), Bacillus (02), Proteus (02), Lactiplantibacillus (01), Klebsiella (01), Citrobacter (01), Brevibacillus (01), E. coli (01) and one unidentified strain were growing during composting. Eleven combinations of bacterial consortium and respective additives were applied for the organic waste decomposition in the next stage, resulting in varied completion periods ranging from 3 to 14 days. Two combinations were completed within 3 days, which are considered ideal combinations for composting. The microbial consortium was significantly diverse, which is a reason for rapid biodegradation. The present study reveals that the technology will be highly feasible for municipal solid waste management in tropical/subtropical countries.

5.
Surg Neurol Int ; 14: 55, 2023.
Article in English | MEDLINE | ID: mdl-36895253

ABSTRACT

Background: Gangliogliomas (GGs) are rare tumors of the central nervous system composed of neoplastic neural and glial cells and are typically low-grade. Intramedullary spinal anaplastic GGs (AGG) are rare, poorly understood, and often aggressive tumors that can result in widespread progression along the craniospinal axis. Due to the rarity of these tumors, data are lacking to guide clinical and pathologic diagnosis and standard of care treatment. Here, we present a case of pediatric spinal AGG to provide information on our institutional approach to work-up and to highlight unique molecular pathology. Case Description: A 13-year-old female presented with signs of spinal cord compression including right sided hyperreflexia, weakness, and enuresis. Magnetic resonance imaging (MRI) revealed a C3-C5 cystic and solid mass which was treated surgically with osteoplastic laminoplasty and tumor resection. Histopathologic diagnosis was consistent with AGG, and molecular testing identified mutations in H3F3A (K27M), TP53, and NF1. She received adjuvant radiation therapy and her neurological symptoms improved. However, at 6-month follow-up, she developed new symptoms. MRI revealed metastatic recurrence of tumor with leptomeningeal and intracranial spread. Conclusion: Primary spinal AGGs are rare tumors, but a growing body of literature shows some trends that may improve diagnosis and management. These tumors generally present in adolescence and early adulthood with motor/sensory impairment and other spinal cord symptoms. They are most commonly treated by surgical resection but frequently recur due to their aggressive nature. Further reports of these primary spinal AGGs along with characterization of their molecular profile will be important in developing more effective treatments.

6.
Pediatr Neurosurg ; 58(2): 80-88, 2023.
Article in English | MEDLINE | ID: mdl-36787706

ABSTRACT

INTRODUCTION: Resection of brain lesions associated with refractory epilepsy to achieve seizure control is well accepted. However, concurrent behavioral effects of these lesions such as changes in mood, personality, and cognition and the effects of surgery on behavior have not been well characterized. We describe 5 such children with epileptogenic lesions and significant behavioral abnormalities which improved after surgery. CASE DESCRIPTIONS: Five children (ages 3-14 years) with major behavioral abnormalities and lesional epilepsy were identified and treated at our center. Behavioral problems included academic impairment, impulsivity, self-injurious behavior, and decreased social interaction with diagnoses of ADHD, oppositional defiant disorder, and autism. Pre-operative neuropsychiatric testing was performed in 4/5 patients and revealed low-average cognitive and intellectual abilities for their age, attentional difficulties, and poor memory. Lesions were located in the temporal (2 gangliogliomas, 1 JPA, 1 cavernoma) and parietal (1 DNET) lobes. Gross total resection was achieved in all cases. At mean 1-year follow-up, seizure freedom (Engel 1a in 3 patients, Engel 1c in 2 patients) and significant behavioral improvements (academic performance, attention, socialization, and aggression) were achieved in all. Two patients manifested violence pre-operatively; one had extreme behavior with violence toward teachers and peers despite low seizure burden. Since surgery, his behavior has normalized. CONCLUSION: We identified 5 patients with severe behavioral disorders in the setting of lesional epilepsy, all of whom demonstrated improvement after surgery. The degree of behavioral abnormality was disproportionate to epilepsy severity, suggesting a more complicated mechanism by which lesional epilepsy impacts behavior. We propose a novel paradigm in which lesionectomy may offer behavioral benefit even when seizures are not refractory. Thus, behavioral improvement may be an important novel goal for neurosurgical resection in children with epileptic brain lesions.


Subject(s)
Brain Neoplasms , Epilepsy , Psychosurgery , Child , Humans , Psychosurgery/adverse effects , Treatment Outcome , Retrospective Studies , Epilepsy/surgery , Epilepsy/etiology , Seizures/etiology , Brain Neoplasms/surgery
7.
J Biomol Struct Dyn ; 41(15): 7248-7264, 2023.
Article in English | MEDLINE | ID: mdl-36093938

ABSTRACT

Salmonella infections are continuously growing. Causative serovars have gained enhanced drug resistance and virulence. Current vaccines have fallen short of providing sufficient protection. mRNA vaccines have come up with huge success against SARS-CoV-2; Pfizer-BioNTech and Moderna vaccines have resulted in >90% efficacy with efficient translocation, expression, and presentation of antigen to the host immune system. Herein, based on the same approach a mRNA vaccine construct has been designed and analyzed against Salmonella by joining regions of genes of outer membrane proteins C and F of S. Typhi through a flexible linker. Construct was flanked by regulatory regions that have previously shown better expression and translocation of encoded protein. GC content of the construct was improved to attain structural and thermodynamic stability and smooth translation. Sites of strong binding miRNAs were removed through codon optimization. Protein encoded by this construct is structurally plausible, highly antigenic, non-allergen to humans, and does not cross-react to the human proteome. It is enriched in potent, highly antigenic, and conserved linear and conformational epitopes. Most conserved conformational epitopes of core protein lie on extended beta hairpins exposed to the cellular exterior. Stability and thermodynamic attributes of the final construct were found highly comparable to the Pfizer-BioNTech vaccine construct. Both contain a stable stem-loop structure downstream of the start codon and do not offer destabilizing secondary structures upstream of the start codon. Given structural and thermodynamic stability, effective immune response, and epitope composition the construct is expected to provide broad-spectrum protection against clinically important Salmonella serovars.Communicated by Ramaswamy H. Sarma.

8.
Cells ; 11(21)2022 10 26.
Article in English | MEDLINE | ID: mdl-36359769

ABSTRACT

The present study discusses a biofilm-positive P. aeruginosa isolate that survives at pH levels ranging from 4.0 to 9.0. The biofilm consortia were colonized with different phenotypes i.e., planktonic, slow-growing and metabolically inactive small colony variants (SCVs). The lower base of the consortia was occupied by SCVs. These cells were strongly attached to solid surfaces and interconnected through a network of nanotubes. Nanotubes were observed at the stationary phase of biofilm indwellers and were more prominent after applying weight to the consortia. The scanning electron micrographs indicated that the nanotubes are polar appendages with intraspecies connectivity. The micrographs indicated variations in physical dimensions (length, width, and height) and a considerable reduction in volume due to weight pressure. A total of 35 cells were randomly selected. The mean volume of cells before the application of weight was 0.288 µm3, which was reduced to 0.144 µm3 after the application of weight. It was observed that a single cell may produce as many as six nanotubes, connected simultaneously to six neighbouring cells in different directions. The in-depth analysis confirmed that these structures were the intra-species connecting tools as no free nanotubes were found. Furthermore, after the application of weight, cells incapable of producing nanotubes were wiped out and the surface was covered by nanotube producers. This suggests that the nanotubes give a selective advantage to the cells to resist harsh environmental conditions and weight pressure. After the removal of weight and proper supply of nutrients, these phenotypes reverted to normal planktonic lifestyles. It is concluded that the nanotubes are not merely the phenomenon of dying cells; rather they are a connectivity tool which helps connected cells to tolerate and resist environmental stress.


Subject(s)
Nanotubes , Pseudomonas aeruginosa , Pseudomonas aeruginosa/metabolism , Biofilms , Plankton
9.
Cureus ; 14(2): e22595, 2022 Feb.
Article in English | MEDLINE | ID: mdl-35371720

ABSTRACT

Objectives We did this study intending to compare the efficacy of rosuvastatin 5 mg and 10 mg in patients of type 2 diabetes mellitus with dyslipidemia by validating their effect on lipid profile and the side effects. Methodology This study was carried out at the outpatient department of a tertiary care hospital in Multan. Three hundred patients of both genders were included. The research approach employed a parallel-controlled, randomized study. After taking relevant history and physical examination, each patient's fasting venous blood samples were taken and sent to the institutional laboratory to analyze glycated hemoglobin (HbA1c), baseline lipid levels for cholesterol, triglycerides, low-density lipoprotein (LDL), very-low-density lipoprotein (VLDL), and high-density lipoprotein (HDL). Patients were divided into two groups based on the drug administered. One group was prescribed rosuvastatin 5 mg, and the other group was prescribed rosuvastatin 10 mg. Patients were followed up after six months to record the latest lipid profile. Data analysis was done through SPSS version 24. Results Patients in the two groups had similar lipid levels to start with. After six months of therapy, total serum cholesterol, triglycerides, and LDL-C were reduced to statistically significant levels in group two compared to group one. However, both groups showed a similar increase in serum levels of HDL-C. Patients treated with 10 mg rosuvastatin showed a slight decrease in BMI. Nine patients treated with 10 mg rosuvastatin reported myalgias compared to only one patient treated with a dose of 5 mg (p<0.005). Conclusion Our study concludes that both 5 mg and 10 mg of rosuvastatin exhibit the antihyperlipidemic effect, but high doses are associated with more side effects. Therefore, physicians should be aware of dose titration related to statins as it will ultimately lead to reduced cardiovascular mortality.

10.
Front Neurosci ; 15: 774073, 2021.
Article in English | MEDLINE | ID: mdl-34819837

ABSTRACT

Introduction: Movement disorders can be common, persistent, and debilitating sequelae of severe traumatic brain injury. Post-traumatic movement disorders are usually complex in nature, involving multiple phenomenological manifestations, and can be difficult to control with medical management alone. Deep brain stimulation (DBS) has been used to treat these challenging cases, but distorted brain anatomy secondary to trauma can complicate effective targeting. In such cases, use of diffusion tractography imaging and inpatient testing with externalized DBS leads can be beneficial in optimizing outcomes. Case Description: We present the case of a 42-year-old man with severe, disabling post-traumatic tremor who underwent bilateral, dual target DBS to the globus pallidus internus (GPi) and a combined ventral intermediate nucleus of the thalamus (Vim)/dentato-rubro-thalamic tracts (DRTT) target. DRTT fiber tracts were reconstructed preoperatively to assist in surgical targeting given the patient's distorted anatomy. Externalization and survey of the four leads extra-operatively with inpatient testing allowed for internalization of the leads that demonstrated benefit. Six months after surgery, the patient's tremor and dystonic burden had decreased by 67% in the performance sub-score of The Essential Tremor Rating Scale (TETRAS). Conclusion: A patient-tailored approach including target selection guided by individualized anatomy and tractography as well as extra-operative externalized lead interrogation was shown to be effective in optimizing clinical outcome in a patient with refractory post-traumatic tremor.

11.
Cureus ; 13(12): e20665, 2021 Dec.
Article in English | MEDLINE | ID: mdl-35103215

ABSTRACT

Background In this study, we aimed to determine the association of lipid and body mass index (BMI) profiles among cases having chronic hepatitis C virus (CHCV) infection. Methodology This cross-sectional study was conducted in the outpatient department of a tertiary care hospital. A total of 320 cases of both genders, aged 18 to 60 years, with CHCV infection were enrolled in the study. After obtaining relevant history and conducting a physical examination, the venous blood sample of each patient was taken and sent to the institutional laboratory to analyze serum total cholesterol, serum triglyceride, low-density lipoprotein, and high-density lipoprotein levels. BMI of all the study participants was also noted. Results Of the total 320 cases, there were 152 (47.5%) males and 168 (52.5%) females. The overall mean age was 42.92 ± 11.38 years. Most cases [97 (30.3%)] were in the 41 to 50-year age group. Overall, the mean BMI was 27.75 ± 4.59 kg/m2. Dyslipidemia was noted in 144 (45.0%) cases. Increasing age and increasing BMI were found to have statistical significance with the presence of dyslipidemia (p < 0.05). Conclusions Increasing age and BMI have a significant association with dyslipidemia in patients with CHCV infection. Lipid profile appears to differ among different age and BMI groups.

12.
Iran J Basic Med Sci ; 23(11): 1494-1498, 2020 Nov.
Article in English | MEDLINE | ID: mdl-33235708

ABSTRACT

OBJECTIVES: This study was designed to investigate the effect of AgNPs (10 nm and 30 nm) on different phenotypes of Staphylococcus aureus biofilm consortia. MATERIALS AND METHODS: A total of eighteen biofilm-producing isolates of Methicillin-Resistant S. aureus (MRSA) were used in the present study. Tube methods, Congo-red agar method, and scanning electron microscopy (SEM) were used to study biofilm phenotypes. Population analysis assay on a tryptone soya agar (TSA) plate was applied to study the different phenotypes of biofilm consortia. The effect of AgNPs was evaluated by broth dilution assay. RESULTS: Results showed that biofilm consortia harbour different phenotypes, i.e., planktonic, metabolically inactive cells, and small colony variants (SCVs) or persister cells. The focus of the present study is the effect of AgNPs on biofilm consortia of MRSA, particularly on the SCVs population. Large size AgNPs (30 nm) were unable to diffuse through extracellular matrix material coverings of the biofilm consortia; they were only active against the planktonic population that occupies the outer surface of consortia. The smaller AgNPs (10 nm), on the other hand, were found to diffuse through the matrix material and hence were effective against planktonic as well as metabolically inactive population of consortia. Moreover, 30 nm AgNPs take 6 hr to disperse off and kill planktonic and upper surface indwellers. The 10 nm AgNPs disperse and kill the majority of biofilm indwellers within 20 min. CONCLUSION: The present study showed that 10 nm AgNPs can easily penetrate inside the biofilm and are active against all of the indwellers of consortia.

13.
Clin Anat ; 33(6): 823-832, 2020 Sep.
Article in English | MEDLINE | ID: mdl-31749198

ABSTRACT

The superior frontal gyrus (SFG) is an important region implicated in a variety of tasks including motor movement, working memory, resting-state, and cognitive control. A detailed understanding of the subcortical white matter of the SFG could improve postoperative morbidity related to surgery around this gyrus. Through DSI-based fiber tractography validated by gross anatomical dissection, we characterized the fiber tracts of the SFG based on their relationships to other well-known neuroanatomic structures. Diffusion imaging from the Human Connectome Project from 10 healthy adult subjects was used for fiber tractography. We evaluated the SFG as a whole based on its connectivity with other regions. All tracts were mapped in both hemispheres, and a lateralization index was calculated based on resultant tract volumes. Ten cadaveric dissections were then performed using a modified Klingler technique to delineate the location of major tracts integrated within the SFG. We identified four major SFG connections: the frontal aslant tract connecting to the inferior frontal gyrus; the inferior fronto-occipital fasciculus connecting to the cuneus, lingual gyrus, and superior parietal lobule; the cingulum connecting to the precuneus and parahippocampal gyrus/uncus; and a callosal fiber bundle connecting the SFG bilaterally. The functional networks of the SFG involve a complex series of white matter tracts integrated within the gyrus, including the FAT, IFOF, cingulum, and callosal fibers. Postsurgical outcomes related to this region may be better understood in the context of the fiber-bundle anatomy highlighted in this study. Clin. Anat. 33:823-832, 2020. © 2019 Wiley Periodicals, Inc.


Subject(s)
Neural Pathways/anatomy & histology , Prefrontal Cortex/anatomy & histology , White Matter/anatomy & histology , Cadaver , Humans
14.
World Neurosurg ; 95: 108-116, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27474459

ABSTRACT

BACKGROUND: Intramedullary spinal cord tumors (IMSCT) account for about 2%-4% of tumors of the central nervous system. Surgical resection continues to be the most effective treatment modality for most intramedullary tumors, with gross total resection leading to preserved neurologic function and improved survival. However, surgical treatment is often difficult and carries significant risk of postoperative neurologic complications. Intraoperative neuromonitoring has been shown to be of clinical importance in the surgical resection of IMSCT. The main monitoring modalities include somatosensory evoked potentials, transcranial motor evoked potentials via limb muscles or spinal epidural space (D-waves), and dorsal column mapping. These monitoring modalities have been shown to inform surgeons intraoperatively and in many cases, have led to alterations in operative decision. METHODS: We reviewed the literature on the usefulness of intraoperative neuromonitoring for intramedullary spinal tumor resection and its role in predicting postoperative neurologic deficits. A MEDLINE search was performed (2000-2015) and 13 studies were reviewed. Detailed information and data from the selected articles were assessed and compiled. Data were extracted showing the role of monitoring in outcomes of surgery. CONCLUSIONS: By using intraoperative somatosensory evoked potentials, transcranial motor evoked potentials, D-waves, and dorsal column mapping, spinal injury could be prevented in most cases, thereby improving postoperative neurologic functioning and outcome in patients undergoing surgery for IMSCT.


Subject(s)
Evoked Potentials, Motor , Evoked Potentials, Somatosensory , Intraoperative Neurophysiological Monitoring/methods , Neurosurgical Procedures/methods , Postoperative Complications/prevention & control , Spinal Cord Neoplasms/surgery , Electric Stimulation , Epidural Space , Humans , Muscle, Skeletal
15.
Pak J Pharm Sci ; 27(5 Spec no): 1571-4, 2014 Sep.
Article in English | MEDLINE | ID: mdl-25176252

ABSTRACT

Escherichia coli (E. coli) are normal flora of the intestines of most animals, including humans. Most strains are harmless and beneficial to host by preventing the establishment of pathogenic bacteria within the intestine. However, some E. coli strains can cause a wide variety of intestinal and extra-intestinal diseases, such as diarrhoea, urinary tract infections, septicaemia, neonatal meningitis and renal complications. Several virulence factors including toxins, adhesins, serine proteases, etc. have been reported in these highly adapted clones. The present study was designed to enumerate toxin genotype through PCR assay in local clinical isolates of E. coli. A total of 37 E. coli strains were collected from different clinical laboratories of Karachi and examined for the presence of shiga toxin 1 (stx1) and shiga toxin 2 (stx2) genes of Eenterohemorrhagic E. Coli (EHEC) and heat stable (st) and healt labile (lt) toxin genes of enterotoxigenic E. Coli (ETEC). It was observed that 16 strains out of 37 carried one or more type of toxin genes. The presence of stx1 gene was significantly higher as it was positive in 10 isolates compared to others toxins. Two in above stx1 positive strains were also carrying for stx2 gene. Six out of 37 isolates were positive for lt gene, and none of the strains are carrying st gene. Although, the study was carried out with fewer isolates, yet it demonstrated the trend of dispersion of toxin genes and findings can be used to correlate the gastro-intestinal infections and their complications in Pakistan.


Subject(s)
Bacterial Toxins/genetics , Bacteriological Techniques , DNA, Bacterial/genetics , Diarrhea/microbiology , Enterotoxigenic Escherichia coli/genetics , Enterotoxins/genetics , Escherichia coli Infections/microbiology , Escherichia coli Proteins/genetics , Polymerase Chain Reaction , Shiga-Toxigenic Escherichia coli/genetics , Bacterial Toxins/isolation & purification , DNA, Bacterial/isolation & purification , Diarrhea/diagnosis , Enterotoxigenic Escherichia coli/classification , Enterotoxigenic Escherichia coli/isolation & purification , Enterotoxigenic Escherichia coli/pathogenicity , Enterotoxins/isolation & purification , Escherichia coli Infections/diagnosis , Escherichia coli Proteins/isolation & purification , Feces/microbiology , Genotype , Humans , Shiga Toxin 1/genetics , Shiga Toxin 1/isolation & purification , Shiga Toxin 2/genetics , Shiga Toxin 2/isolation & purification , Shiga-Toxigenic Escherichia coli/classification , Shiga-Toxigenic Escherichia coli/isolation & purification , Shiga-Toxigenic Escherichia coli/pathogenicity
16.
Braz. arch. biol. technol ; 56(4): 645-652, July-Aug. 2013. ilus, graf, tab
Article in English | LILACS | ID: lil-684517

ABSTRACT

In this study, a variety of samples were screened for the presence of PHA synthase gene. Results showed that 16 out of 102 isolated were positive for PHA respective genes. The highest prevalence was observed in Pseudomonas aeruginosa. The capability of PHA production was also shown by growing these strains on the defined medium and subsequent analysis using intracellular granules staining and Fourier transform infrared spectroscopy (FT-IR). The microscopic analysis showed that the positive strains accumulated PHA in the cell. The FT-IR analysis showed the presence of PHA peaks in the dried cells as well as in extraction product. P aeruginosa strain P7 showed higher concentration of PHA compared to the others as demonstrated by the highest respective peaks in FT-IR.

17.
Infect Immun ; 78(10): 4294-301, 2010 Oct.
Article in English | MEDLINE | ID: mdl-20643852

ABSTRACT

Hemolytic-uremic syndrome (HUS) is a life-threatening disorder characterized by hemolytic anemia, thrombocytopenia, and renal insufficiency. It is caused mainly by infections with enterohemorrhagic Escherichia coli (EHEC). Recently, Shiga toxin 2, the best-studied virulence factor of EHEC, was reported to interact with complement, implying that complement may be involved in the pathogenesis of EHEC-induced HUS. The aim of the present study was to investigate whether or not the serine protease EspP, an important virulence factor of EHEC, interacts with complement proteins. EspP did not have any effect on the integrity of factor H or factor I. However, EspP was shown to cleave purified C3/C3b and C5. Cleavage of the respective complement proteins also occurred in normal human serum (NHS) as a source of C3/C3b or C5 or when purified complement proteins were added to the supernatant of an EspP-producing wild-type strain. Edman degradation allowed unequivocal mapping of all three main C3b fragments but not of the three main C5 fragments. Complement activation was significantly downregulated in all three pathways for C5-depleted serum to which C5, preincubated with EspP, was added (whereas C5 preincubated with an EspP mutant was able to fully reconstitute complement activation). This indicates that EspP markedly destroyed the functional activity, as measured by a commercial total complement enzyme-linked immunosorbent assay (Wieslab). Downregulation of complement by EspP in vivo may influence the colonization of EHEC bacteria in the gut or the disease severity of HUS.


Subject(s)
Complement Activation/drug effects , Complement C3/metabolism , Complement C3b/metabolism , Complement C5/metabolism , Enterohemorrhagic Escherichia coli/enzymology , Escherichia coli Proteins/metabolism , Serine Endopeptidases/metabolism , Complement C3/chemistry , Complement C3b/chemistry , Complement C5/chemistry , Escherichia coli Proteins/genetics , Gene Expression Regulation, Enzymologic , Hemolytic-Uremic Syndrome/microbiology , Humans , Serine Endopeptidases/genetics
18.
J Immunol ; 182(10): 6394-400, 2009 May 15.
Article in English | MEDLINE | ID: mdl-19414792

ABSTRACT

Infections with enterohemorrhagic Escherichia coli (EHEC) are a major cause of hemolytic uremic syndrome (HUS). Shiga toxins (Stxs), especially Stx2, are believed to represent major virulence factors of EHEC, contributing to HUS pathogenesis. Beside EHEC-associated HUS, there are hereditary atypical forms of HUS, which are mostly caused by mutations of complement regulators. The aim of the present study was to investigate whether or not complement is also involved in the pathogenesis of EHEC-induced typical HUS, by being activated either directly or indirectly by involvement of its inhibitors. Purified Stx2 markedly activated complement via the alternative pathway and was found to bind to factor H (FH), however, only when it was active. No apparent cleavage or destruction of FH was visible, and cofactor activity in fluid phase was unaffected, but clearly delayed for surface-attached FH, where it is essential for host cell protection. Binding studies using FH constructs revealed that Stx2 binds to short consensus repeats (SCRs) 6-8 and SCRs18-20, but not to SCRs16-17, i.e., to regions involved in the surface recognition function of FH. In conclusion, complement, and in particular FH, not only plays an important role in atypical HUS, but most probably also in EHEC-induced HUS.


Subject(s)
Complement Activation/physiology , Complement Factor H/metabolism , Hemolytic-Uremic Syndrome/metabolism , Shiga Toxin/metabolism , Animals , Blotting, Western , CHO Cells , Cricetinae , Cricetulus , Enterohemorrhagic Escherichia coli , Enzyme-Linked Immunosorbent Assay , Escherichia coli Infections/complications , Hemolytic-Uremic Syndrome/microbiology , Humans , Immunoprecipitation
19.
Int J Med Microbiol ; 299(4): 247-54, 2009 Apr.
Article in English | MEDLINE | ID: mdl-19036636

ABSTRACT

Besides Shiga toxins (Stx), Stx-producing Escherichia coli (STEC) harbour several other putative virulence factors, including the serine protease EspP. We have investigated 214 STEC strains from Austria belonging to 61 different serotypes from humans, animals, and food for the presence of this serine protease gene and have determined the espP subtypes and their association with clinical outcome. espP was detected in 121 (57%) out of 214 strains. Sixty-five of 68 strains (96%) of non-sorbitol-fermenting (NSF) O157:H7/NM (NM, non-motile) were positive for espP, while none of 8 SF E. coli O157:NM isolates contained this gene. All 9 strains of serotype O145:NM and 17 of 21 strains (81%) of serotype O26:H11/NM were positive for espP. Nineteen STEC serogroups including O103 and O111 serogroups--considered to be highly pathogenic--were completely negative for espP. Only 5 of 12 strains isolated from patients suffering from haemolytic uraemic syndrome (HUS) were espP-positive (all serogroup NSF O157) as well as 28 of 39 strains from patients with bloody diarrhoea, 40 of 63 strains from patients with non-bloody diarrhoea, and 15 of 19 strains from asymptomatic patients. In O157:H7/NM, O26:H11/NM, and O145:NM only espP subtype alpha was found, whereas in most of the other non-O157 serogroups, subtypes beta and gamma were found. Subtype delta was not detected in our strain collection. Regarding the espP subtypes, only subtype alpha, but not beta and gamma, were found in HUS patients. Moreover, we could demonstrate that espP, and in particular subtype alpha, is associated with highly pathogenic serogroups.


Subject(s)
Escherichia coli Proteins/genetics , Serine Endopeptidases/genetics , Shiga-Toxigenic Escherichia coli/enzymology , Shiga-Toxigenic Escherichia coli/pathogenicity , Virulence Factors/genetics , Animals , Austria , DNA, Bacterial/genetics , Escherichia coli Infections/microbiology , Escherichia coli Infections/veterinary , Food Microbiology , Genotype , Humans , Polymerase Chain Reaction/methods , Serotyping , Shiga-Toxigenic Escherichia coli/classification , Shiga-Toxigenic Escherichia coli/genetics , Shiga-Toxigenic Escherichia coli/isolation & purification
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