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1.
Iran J Microbiol ; 16(2): 201-207, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38854975

RESUMO

Background and Objectives: Needle stick injury (NSI) is the most dreaded occupational health hazard affecting a healthcare worker (HCW) psychologically and physically. The risk of infection post needle stick injury ranges between 1.9% to greater than 40% for HBV infections, 2.7-10% for HCV and 0.2-0.44% for HIV infections. As per National AIDS Control Organisation (NACO) records, nursing staff is at highest risk (43%) followed by physicians (28%). The main objective of this study was to evaluate knowledge of nursing staff about needle stick injuries and to study factors leading to such incidents in their working areas, impart them knowledge regarding the same and fill gaps in knowledge. Materials and Methods: This is a cross-sectional retrospective analysis involving nursing staff and students. p values were calculated using SPSS software. Results: Overall NSI prevalence among nursing staff and students was 51.6% whereas in more exposed and less exposed group was 47.45% and 10.16% respectively (p=0.2056). The most common cause of NSI incident was recapping of needle (38.5%) followed by transferring needle to sharp container (35%). Conclusion: Consequences of NSI are serious and this study has tried to emphasize on the need to study the factors leading to NSI.

2.
JCO Glob Oncol ; 10: e2300292, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38301183

RESUMO

PURPOSE: Febrile neutropenia (FN) is a serious complication in hematologic malignancies, and lung infiltrates (LIs) remain a significant concern. An accurate microbiological diagnosis is crucial but difficult to establish. To address this, we analyzed the utility of a standardized method for performing bronchoalveolar lavage (BAL) along with a two-step strategy for the analysis of BAL fluid. PATIENTS AND METHODS: This prospective observational study was conducted at a tertiary cancer center from November 2018 to June 2020. Patients age 15 years and older with confirmed leukemia or lymphomas undergoing chemotherapy, with presence of FN, and LIs observed on imaging were enrolled. RESULTS: Among the 122 enrolled patients, successful BAL was performed in 83.6% of cases. The study used a two-step analysis of BAL fluid, resulting in a diagnostic yield of 74.5%. Furthermore, antimicrobial therapy was modified in 63.9% of patients on the basis of BAL reports, and this population demonstrated a higher response rate (63% v 45%; P = .063). CONCLUSION: Our study demonstrates that a two-step BAL fluid analysis is safe and clinically beneficial to establish an accurate microbiological diagnosis. Given the crucial impact of diagnostic delays on mortality in hematologic malignancy patients with FN, early BAL studies should be performed to enable prompt and specific diagnosis, allowing for appropriate treatment modifications.


Assuntos
Neutropenia Febril , Neoplasias Hematológicas , Leucemia , Linfoma , Adolescente , Humanos , Líquido da Lavagem Broncoalveolar/microbiologia , Neutropenia Febril/diagnóstico , Neutropenia Febril/tratamento farmacológico , Neutropenia Febril/etiologia , Neoplasias Hematológicas/complicações , Neoplasias Hematológicas/microbiologia , Neoplasias Hematológicas/patologia , Leucemia/complicações , Leucemia/patologia , Pulmão/microbiologia , Pulmão/patologia , Linfoma/complicações , Linfoma/diagnóstico , Linfoma/tratamento farmacológico , Estudos Prospectivos
3.
J Glob Infect Dis ; 15(3): 121-123, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37800087

RESUMO

Delftia acidovorans (D. acidovorans) is an aerobic, nonfermentative Gram-negative bacillus infrequently isolated from clinical specimens. The pathogenicity and clinical significance of the organism has not been ascertained due to uncommon clinical isolation and suspected low virulence. The organism has been reported to be inherently resistant to aminoglycoside group of drugs which remain as a widely used first-line drug of choice for febrile neutropenic patients. Hereby, we report a case of D. acidovorans-associated pleural effusion in a patient of metastatic adenocarcinoma diagnosed and treated timely and successfully with appropriate antibiotics.

4.
J Surg Oncol ; 128(4): 692-700, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37232552

RESUMO

INTRODUCTION: Unplanned hospital readmission (UHR) is an important indicator of the quality of the healthcare system in place. It has various implications for the patients and the healthcare system at large. In this article, we have attempted to understand the various factors influencing UHR and the start of adjuvant treatment following cancer surgery. PATIENTS & METHODS: In this study adult patients above 18 years of age with upper aerodigestive tract squamous cell carcinoma who underwent surgery at our center between July 2019 to December 2019 were included in the study. Various factors influencing UHR and delay in receiving adjuvant treatment were analyzed. RESULTS: A total of 245 patients satisfied the inclusion criteria. Surgical site infection (SSI) was the factor that had the maximum influence on the UHR (p < 0.002, OR: 5.6, 95% CI: [1.911-16.4]) and delaying the start of adjuvant treatment (p = 0.008, OR: 3.786, 95% CI: [1.421-10.086]) on multivariate analysis. Surgery lasting for >4 h and patients who had received prior treatment tended to develop SSI postoperatively. The presence of SSI also seemed to have had a negative influence on disease-free survival (DFS) as well. CONCLUSIONS: SSI is an important postoperative complication having major implications in terms of increased UHR and delays in starting adjuvant treatment which in turn is reflected as a poorer DFS among patients who develop SSI postoperatively.


Assuntos
Carcinoma de Células Escamosas , Infecção da Ferida Cirúrgica , Adulto , Humanos , Infecção da Ferida Cirúrgica/epidemiologia , Infecção da Ferida Cirúrgica/etiologia , Intervalo Livre de Doença , Readmissão do Paciente , Carcinoma de Células Escamosas/cirurgia , Carcinoma de Células Escamosas/patologia , Fatores de Risco , Estudos Retrospectivos
5.
Infect Control Hosp Epidemiol ; 44(8): 1261-1266, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-36278508

RESUMO

OBJECTIVE: To identify risk factors for mortality in intensive care units (ICUs) in Asia. DESIGN: Prospective cohort study. SETTING: The study included 317 ICUs of 96 hospitals in 44 cities in 9 countries of Asia: China, India, Malaysia, Mongolia, Nepal, Pakistan, Philippines, Sri Lanka, Thailand, and Vietnam. PARTICIPANTS: Patients aged >18 years admitted to ICUs. RESULTS: In total, 157,667 patients were followed during 957,517 patient days, and 8,157 HAIs occurred. In multiple logistic regression, the following variables were associated with an increased mortality risk: central-line-associated bloodstream infection (CLABSI; aOR, 2.36; P < .0001), ventilator-associated event (VAE; aOR, 1.51; P < .0001), catheter-associated urinary tract infection (CAUTI; aOR, 1.04; P < .0001), and female sex (aOR, 1.06; P < .0001). Older age increased mortality risk by 1% per year (aOR, 1.01; P < .0001). Length of stay (LOS) increased mortality risk by 1% per bed day (aOR, 1.01; P < .0001). Central-line days increased mortality risk by 2% per central-line day (aOR, 1.02; P < .0001). Urinary catheter days increased mortality risk by 4% per urinary catheter day (aOR, 1.04; P < .0001). The highest mortality risks were associated with mechanical ventilation utilization ratio (aOR, 12.48; P < .0001), upper middle-income country (aOR, 1.09; P = .033), surgical hospitalization (aOR, 2.17; P < .0001), pediatric oncology ICU (aOR, 9.90; P < .0001), and adult oncology ICU (aOR, 4.52; P < .0001). Patients at university hospitals had the lowest mortality risk (aOR, 0.61; P < .0001). CONCLUSIONS: Some variables associated with an increased mortality risk are unlikely to change, such as age, sex, national economy, hospitalization type, and ICU type. Some other variables can be modified, such as LOS, central-line use, urinary catheter use, and mechanical ventilation as well as and acquisition of CLABSI, VAE, or CAUTI. To reduce mortality risk, we shall focus on strategies to reduce LOS; strategies to reduce central-line, urinary catheter, and mechanical ventilation use; and HAI prevention recommendations.


Assuntos
Infecções Relacionadas a Cateter , Infecção Hospitalar , Pneumonia Associada à Ventilação Mecânica , Infecções Urinárias , Adulto , Criança , Humanos , Feminino , Infecções Relacionadas a Cateter/epidemiologia , Estudos Prospectivos , Infecção Hospitalar/epidemiologia , Unidades de Terapia Intensiva , Fatores de Risco , Hospitais Universitários , Atenção à Saúde , Paquistão/epidemiologia
7.
Nat Cancer ; 3(5): 547-551, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35379984

RESUMO

Patients with cancer are at higher risk for adverse coronavirus disease 2019 (COVID-19) outcomes. Here, we studied 1,253 patients with cancer, who were diagnosed with severe acute respiratory syndrome coronavirus 2 at a tertiary referral cancer center in India. Most patients had mild disease; in our settings, recent cancer therapies did not impact COVID-19 outcomes. Advancing age, smoking history, concurrent comorbidities and palliative intent of treatment were independently associated with severe COVID-19 or death. Thus, our study provides useful insights into cancer management during the COVID-19 pandemic.


Assuntos
COVID-19 , Neoplasias , COVID-19/epidemiologia , Humanos , Neoplasias/epidemiologia , Pandemias , Fatores de Risco , SARS-CoV-2
8.
J Surg Oncol ; 125(4): 564-569, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34783365

RESUMO

BACKGROUND AND OBJECTIVES: The COVID-19 pandemic, with high rate of asymptomatic infections and increased perioperative complications, prompted widespread adoption of screening methods. We analyzed the incidence of asymptomatic infection and perioperative outcomes in patients undergoing cancer surgery. We also studied the impact on subsequent cancer treatment in those with COVID-19. METHODS: All patients who underwent elective and emergency cancer surgery from April to September 2020 were included. After screening for symptoms, a preoperative test was performed from nasopharyngeal and oropharyngeal swabs before the procedure. Patients were followed up for 30 days postoperatively and complications were noted. RESULTS: 2108 asymptomatic patients were tested, of which 200 (9.5%) tested positive. Of those who tested positive, 140 (70%) underwent the planned surgery at a median of 30 days from testing positive, and 20 (14.3%) had ≥ Grade III complications. Forty (20%) patients did not receive the intended treatment; 110 patients were retested in the Postoperative period, and 41 (37.3%) tested positive and 9(22%) patients died of COVID-related complications. CONCLUSION: Routine preoperative testing for COVID-19 helps to segregate patients with asymptomatic infection. Higher complications occur in those who develop COVID-19 in postoperative period. Prolonged delay in surgery after COVID infection may influence planned treatment.


Assuntos
Infecções Assintomáticas/epidemiologia , Teste para COVID-19 , COVID-19/epidemiologia , Neoplasias/cirurgia , Complicações Pós-Operatórias/etiologia , Cuidados Pré-Operatórios , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , COVID-19/complicações , COVID-19/diagnóstico , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Incidência , Índia/epidemiologia , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Neoplasias/complicações , Complicações Pós-Operatórias/diagnóstico , Complicações Pós-Operatórias/epidemiologia , Estudos Retrospectivos , Fatores de Risco , Adulto Jovem
9.
Indian J Crit Care Med ; 25(4): 421-428, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34045810

RESUMO

BACKGROUND: Ventilator-associated pneumonia (VAP) is an important cause of healthcare-associated infections, resulting in prolonged hospitalization with increased morbidity and mortality. Knowledge of predominant local pathogens and their antimicrobial susceptibility patterns helps in selection of appropriate initial antibiotic therapy in these critical cases. AIM AND OBJECTIVE: The aim and objective of this study is to characterize the microbiology and antimicrobial susceptibility patterns of VAP isolates in a tertiary cancer center. MATERIALS AND METHODS: This is a 4-year qualitative observational study carried out at a tertiary care cancer hospital in Mumbai. All nondirect bronchoalveolar lavage specimens from patients with a clinical suspicion of VAP sent from the critical care unit to the department of microbiology were processed as per standard laboratory procedures. All isolates were identified to species level and an antimicrobial susceptibility testing was performed by the Kirby-Bauer disk diffusion method and/or the VITEK 2 automated identification and susceptibility system, according to Clinical and Laboratory Standards Institute guidelines. RESULTS: The study comprised 1,074 patients: 710 (66.10%) men and 364 (33.90%) women. A total of 827 bacterial isolates were obtained with 780 (94.32%) gram-negative organisms and 47 (5.68%) gram-positive organisms; of which Acinetobacter baumannii (38.7%), Pseudomonas aeruginosa (17.5%), and Klebsiella pneumoniae (16.6%) were the commonest. Of gram-negative bacilli, multidrug-resistant organisms constituted 87.50% and were susceptible to colistin. CONCLUSIONS: VAP is associated with pathogens, such as A. baumannii, P. aeruginosa, and K. pneumoniae in our setting. High rates of resistance to aminoglycosides, ß-lactam-ß-lactamase inhibitor combinations, and carbapenems were noted. HOW TO CITE THIS ARTICLE: Sangale A, Bhat V, Kelkar R, Biswas S. Microbiology of Ventilator-associated Pneumonia in a Tertiary Care Cancer Hospital. Indian J Crit Care Med 2021;25(4):421-428.

10.
JCO Glob Oncol ; 6: 1684-1695, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33156719

RESUMO

PURPOSE: Infections remain a major challenge in the treatment of acute myeloid leukemia (AML). Induction-related mortality reported in the literature is approximately < 5% in clinical trials. However, the real-world scenario is different, especially in developing countries, given the high incidence of multidrug-resistant (MDR) organisms, high incidence of fungal pneumonia at baseline, and significant delay before initiation of chemotherapy. We aimed to look at contemporary infections and infection-related mortality and analyze the patterns of infections. MATERIALS AND METHODS: This retrospective study was conducted at a large tertiary care oncology center in India. Patients with newly diagnosed AML who were older than age 15 years, considered fit for intensive therapy, and treated in the general wards of the adult hematolymphoid unit from March 1, 2014, until December 31, 2015, were included. RESULTS: One hundred twenty-one patients were treated during the study period. The most common presenting complaint was fever (85%). The focus of infection at presentation was found in 63% of patients, with respiratory infection being the most common (47%). MDR organisms were isolated in 55% of patients during induction from various foci. Klebsiella pneumoniae was the most common blood culture isolate (42.9%). Fungal pneumonia was diagnosed in 55% of patients during induction despite antifungal prophylaxis. Treatment-related mortality was 10.7% in all phases, with an induction mortality rate of 7.4%. Complete remission was attained in 69% of patients. Of all patients who received induction chemotherapy, 74% completed all three consolidation cycles. The 121 patients were followed up for a median period of 53 months. Four-year event-free survival was 35.8%, and 4-year overall survival was 41.5%. CONCLUSION: Infections and infection-related mortality are major challenges during AML induction. Gram-negative MDR and fungal infections are particularly common in our region.


Assuntos
Leucemia Mieloide Aguda , Adolescente , Adulto , Humanos , Índia/epidemiologia , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/epidemiologia , Prevalência , Estudos Retrospectivos , Centros de Atenção Terciária
11.
J Pediatr Hematol Oncol ; 42(4): e202-e206, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-31815886

RESUMO

BACKGROUND: Outcomes of childhood hematolymphoid malignancies have improved several fold because of immunosuppressive chemotherapy and broad-spectrum antibiotics for managing febrile neutropenia. An apparent trade-off has been an increase in invasive fungal disease (IFD), affecting multiple organs. We report the diagnostic and therapeutic challenges in 8 children with lymphoid cancers who developed intracranial (IC) fungal abscesses between 2010 and 2017. METHODS: Children below 15 years of age undergoing treatment for leukemia/lymphoma with clinicoradiologic and microbiologic evidence of IC fungal abscess were included. Demographic details, clinical profile, and management were retrospectively audited. Treatment was guided by European Organization for Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG) definitions for IFD with therapeutic drug monitoring (TDM)-directed azole dosing, and surgical intervention. RESULTS: Eight patients (4 B-cell acute lymphoblastic leukemia, 2 relapsed B-cell acute lymphoblastic leukemia, and 2 non-Hodgkin lymphoma) were eligible for analysis. Proven, probable, and possible IFDs were seen in 2 (25%), 4 (50%), and 2 (25%) patients, respectively. Proven IFDs were invasive mucormycosis with remaining having mold infections. Cerebrospinal fluid galactomannan was positive in all 4 patients in whom it was tested. TDM was possible in 5/8 (63%) patients. Antifungal therapy was given for a median period of 4.2 months with 5 (63%) patients having complete resolution. Three (37%) patients expired, of which 2 were attributable to IFDs. CONCLUSIONS: IC fungal abscesses in children can cause significant morbidity and mortality in children with hematolymphoid cancers. Evaluation of cerebrospinal fluid galactomannan may help in early diagnosis and therapy. Prolonged antifungal therapy steered by TDM can help achieve resolution in some cases.


Assuntos
Antifúngicos/administração & dosagem , Infecções Fúngicas do Sistema Nervoso Central/tratamento farmacológico , Linfoma não Hodgkin/tratamento farmacológico , Mucormicose/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/tratamento farmacológico , Adolescente , Antifúngicos/farmacocinética , Infecções Fúngicas do Sistema Nervoso Central/líquido cefalorraquidiano , Criança , Pré-Escolar , Feminino , Galactose/análogos & derivados , Humanos , Linfoma não Hodgkin/líquido cefalorraquidiano , Linfoma não Hodgkin/mortalidade , Masculino , Mananas/líquido cefalorraquidiano , Mucormicose/líquido cefalorraquidiano , Leucemia-Linfoma Linfoblástico de Células Precursoras B/líquido cefalorraquidiano , Leucemia-Linfoma Linfoblástico de Células Precursoras B/mortalidade , Estudos Retrospectivos
12.
Biol Blood Marrow Transplant ; 25(9): 1832-1836, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31054984

RESUMO

Cytomegalovirus (CMV) reactivations are common after allogeneic stem cell transplants, and pre-emptive therapy has been found to be effective. However, in India, treatment options are limited because of high cost and toxicity of ganciclovir and unavailability of cidofovir and foscarnet. Leflunomide is a cheap and easily available anti-rheumatoid arthritis drug that has been shown to have anti-CMV properties both in vitro and in vivo. It also has been used effectively for CMV reactivation after renal transplants. In this retrospective analysis, we analyzed 70 allogeneic stem cell transplants that were conducted between April 2015 and February 2017. There were 49 episodes of CMV reactivations in 43 patients in this period. Leflunomide was used in 24 episodes. It was effective in CMV clearance in 9 of the 24 episodes (38%). When the CMV copy number was <2 × 103 copies/mL, leflunomide was effective in 9 of 17 (53%) episodes, but when the copy number was >2 × 103, leflunomide was ineffective in all of the 7 episodes. This difference was statistically significant (P= .022 by Fisher exact test), suggesting that leflunomide may be more effective in clearance of CMV when copy numbers are low.


Assuntos
Infecções por Citomegalovirus/tratamento farmacológico , Citomegalovirus , Leflunomida/administração & dosagem , Transplante de Células-Tronco , Adulto , Aloenxertos , Infecções por Citomegalovirus/sangue , Infecções por Citomegalovirus/etiologia , DNA Viral/sangue , Feminino , Humanos , Masculino , Estudos Retrospectivos
13.
Indian J Med Paediatr Oncol ; 37(1): 20-4, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27051152

RESUMO

INTRODUCTION: This increased risk of bacterial infections in the cancer patient is further compounded by the rising trends of antibiotic resistance in commonly implicated organisms. In the Indian setting this is particularly true in case of Gram negative bacilli such as Escherichia coli, Klebsiella pneumoniae and Acinetobacter spp. Increasing resistance among Gram positive organisms is also a matter of concern. The aim of this study was to document the common organisms isolated from bacterial infections in cancer patients and describe their antibiotic susceptibilities. METHODS: We conducted a 6 month study of all isolates from blood, urine, skin/soft tissue and respiratory samples of patients received from medical and surgical oncology units in our hospital. All samples were processed as per standard microbiology laboratory operating procedures. Isolates were identified to species level and susceptibility tests were performed as per Clinical Laboratory Standards Institute (CLSI) guidelines -2012. RESULTS: A total of 285 specimens from medical oncology (114) and surgical oncology services (171) were cultured. Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Acinetobacter spp. were most commonly encountered. More than half of the Acinetobacter strains were resistant to carbapenems. Resistance in Klebsiella pneumoniae to cephalosporins, fluoroquinolones and carbapenems was >50%. Of the Staphylococcus aureus isolates 41.67% were methicillin resistant. CONCLUSION: There is, in general, a high level of antibiotic resistance among gram negative bacilli, particularly E. coli, Klebsiella pneumoniae and Acinetobacter spp. Resistance among Gram positives is not as acute, although the MRSA incidence is increasing.

14.
Int Health ; 7(5): 354-9, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25487724

RESUMO

BACKGROUND: Surgical site infections are a threat to patient safety. However, in India, data on their rates stratified by surgical procedure are not available. METHODS: From January 2005 to December 2011, the International Nosocomial Infection Control Consortium (INICC) conducted a cohort prospective surveillance study on surgical site infections in 10 hospitals in 6 Indian cities. CDC National Healthcare Safety Network (CDC-NHSN) methods were applied and surgical procedures were classified into 11 types, according to the ninth edition of the International Classification of Diseases. RESULTS: We documented 1189 surgical site infections, associated with 28 340 surgical procedures (4.2%; 95% CI: 4.0-4.4). Surgical site infections rates were compared with INICC and CDC-NHSN reports, respectively: 4.3% for coronary bypass with chest and donor incision (4.5% vs 2.9%); 8.3% for breast surgery (1.7% vs 2.3%); 6.5% for cardiac surgery (5.6% vs 1.3%); 6.0% for exploratory abdominal surgery (4.1% vs 2.0%), among others. CONCLUSIONS: In most types of surgical procedures, surgical site infections rates were higher than those reported by the CDC-NHSN, but similar to INICC. This study is an important advancement towards the knowledge of surgical site infections epidemiology in the participating Indian hospitals that will allow us to introduce targeted interventions.


Assuntos
Infecção Hospitalar/epidemiologia , Hospitais , Infecção da Ferida Cirúrgica/epidemiologia , População Urbana , Feminino , Humanos , Índia/epidemiologia , Controle de Infecções , Estudos Prospectivos
15.
Hum Immunol ; 75(8): 880-6, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24984237

RESUMO

Infection with Mycobacteriumtuberculosis possibly depends on host genetic factors and is thought to be the major cause of differential susceptibility to the disease. In the present study, 205 pulmonary tuberculosis cases and 127 healthy controls were studied for the association of Toll-like Receptor (TLR) variants (TLR1 variants 743A>G and 1805T>G, and TLR6 variant 745 C>T) in north Indian population. The frequency of heterozygous genotypes (AG) in TB cases (0.47) and HCs (0.61), differed significantly (p value = 0.02). The association of AG genotypes in HCs was adjusted for gender as gender was observed to be a confounder and M-H OR was found to be 0.62 (p = 0.044). On categorizing the cases basing on AFB smear positivity, the heterozygous genotypes (AG) was found to be associated with low bacillary load (scanty and 1+) (P = 0.002). No association was observed for either TLR1 1805 T>G or TLR6 745 C>T polymorphism. Level of serum IL6 was found to be significantly higher among healthy controls with TLR1 GG genotype compared to healthy controls with AA (p = 0.035) and AG (p = 0.005) genotypes. Thus, it may be suggested that the heterozygous condition for TLR1 743 A>G provide resistance from the disease. However, in depth study is required to understand the mechanism for possible protective responses.


Assuntos
Polimorfismo Genético , Receptor 1 Toll-Like/genética , Receptor 6 Toll-Like/genética , Tuberculose Pulmonar/genética , Adolescente , Adulto , Idoso , Alelos , Carga Bacteriana , Estudos de Casos e Controles , Criança , Feminino , Frequência do Gene , Predisposição Genética para Doença , Haplótipos , Heterozigoto , Humanos , Índia , Interleucina-6/genética , Interleucina-6/imunologia , Masculino , Pessoa de Meia-Idade , Mycobacterium tuberculosis/imunologia , Receptor 1 Toll-Like/imunologia , Receptor 6 Toll-Like/imunologia , Tuberculose Pulmonar/imunologia , Tuberculose Pulmonar/patologia
19.
ACS Appl Mater Interfaces ; 3(7): 2512-21, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21682303

RESUMO

In lubricated sliding contacts, components wear out and the lubricating oil ages with time. The present work explores the interactive influence between lubricant aging and component wear. The flat face of a steel pin is slid against a rotating steel disk under near isothermal conditions while the contact is immersed in a reservoir of lubricant (hexadecane). The chemical changes in the oil with time are measured by vibrational spectroscopy and gas chromatography. The corresponding chemistry of the pin surface is recorded using X-ray photoelectron spectroscopy while the morphology of the worn pins; surface and subsurface, are observed using a combination of focused ion beam milling and scanning electron microscopy. When compared to thermal auto-oxidation of the lubricant alone, steel on steel friction and wear are found to accentuate the decomposition of oil and to reduce the beneficial impact of antioxidants. The catalytic action of nascent iron, an outcome of pin wear and disk wear, is shown to contribute to this detrimental effect. Over long periods of sliding, the decomposition products of lubricant aging on their own, as well as in conjunction with their products of reaction with iron, generate a thick tribofilm that is highly protective in terms of friction and wear.

20.
J Colloid Interface Sci ; 348(1): 255-64, 2010 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-20447645

RESUMO

With an objective to understand the nature of forces which contribute to the disjoining pressure of a thin water film on a steel substrate being pressed by an oil droplet, two independent sets of experiments were done. (i) A spherical silica probe approaches the three substrates; mica, PTFE and steel, in a 10mM electrolyte solution at two different pHs (3 and 10). (ii) The silica probe with and without a smeared oil film approaches the same three substrates in water (pH=6). The surface potential of the oil film/water was measured using a dynamic light scattering experiment. Assuming the capacity of a substrate for ion exchange the total interaction force for each experiment was estimated to include the Derjaguin-Landau-Verwey-Overbeek (DLVO) force, hydration repulsion, hydrophobic attraction and oil-capillary attraction. The best fit of these estimates to the force-displacement characteristics obtained from the two sets of experiment gives the appropriate surface potentials of the substrates. The procedure allows an assessment of the relevance of a specific physical interaction to an experimental configuration. Two of the principal observations of this work are: (i) The presence of a surface at constant charge, as in the presence of an oil film on the probe, significantly enhances the counterion density over what is achieved when both the surfaces allow ion exchange. This raises the corresponding repulsion barrier greatly. (ii) When the substrate surface is wettable by oil, oil-capillary attraction contributes substantially to the total interaction. If it is not wettable the oil film is deformed and squeezed out.

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