Australian Nurse Engagement in Eye Care: A National Survey.

Purpose: An estimated 13 million Australians live with one or more chronic eye conditions, with prevalence increasing. Eye care services today and in the future rely on effective workforces, in which nurses play a pivotal role. Despite nurse involvement in eye care, there is no information describing their engagement, deployment, training, and opinion. This paper offers the first review of nurse engagement in eye care in Australia. Methods: We conducted an e-survey on Australian nurse engagement in eye care. Quantitative questions were analysed by descriptive, chi-square and bivariate correlation coefficients with assumed power of 0.80, and significance of p=0.05. Grounded theory, sentiment and saturation analysis extracted key themes, meaning and opinion from the qualitative questions. Results: There were n=238 Australian nurse participants. Results indicated they were satisfied with their role, engaged in a wide range of healthcare and eye care setting and organisations, and adapted to their employer. Task-shifting "to" and "from" nurses was not universally supported but recognised by participants as necessary. Of concern, the results suggested that 68.6% of our participants would exit eye care over the next ten years, with insufficient entry pathways into the field for graduate and early-career nurses. Conclusion: For Australia to meet and sustain eye care services for its population, steps must be taken to improve exposure and entry to the field for students, graduates, and early-career nurses. Strategies to train and prepare nurses for task-shifting are urgently required and the eye care nursing sector must professionalise to achieve positive change.

Midbrain organoids for Parkinson's disease (PD) - A powerful tool to understand the disease pathogenesis.

Brain Organiods (BOs) are a promising technique for researching disease progression in the human brain. These organoids, which are produced from human induced pluripotent stem cells (HiPSCs), can construct themselves into structured frameworks. In the context of Parkinson's disease (PD), recent advancements have been made in the development of Midbrain organoids (MBOs) models that consider key pathophysiological mechanisms such as alpha-synuclein (α-Syn), Lewy bodies, dopamine loss, and microglia activation. However, there are limitations to the current use of BOs in disease modelling and drug discovery, such as the lack of vascularization, long-term differentiation, and absence of glial cells. To address these limitations, researchers have proposed the use of spinning bioreactors to improve oxygen and nutrient perfusion. Modelling PD utilising modern experimental in vitro models is a valuable tool for studying disease mechanisms and elucidating previously unknown features of PD. In this paper, we exclusively review the unique methods available for cultivating MBOs using a pumping system that mimics the circulatory system. This mechanism may aid in delivering the required amount of oxygen and nutrients to all areas of the organoids, preventing cell death, and allowing for long-term culture and using co-culturing techniques for developing glial cell in BOs. Furthermore, we emphasise some of the significant discoveries about the BOs and the potential challenges of using BOs will be discussed.

In vitro biomechanics of divot use, and their placement, in orthodontic aligner therapy.

INTRODUCTION: To evaluate biomechanics of an aligner utilizing divots and the effect of their vertical placement on the right maxillary central incisor. METHODS: An in vitro Orthodontic SIMulator (OSIM) was used to test forces and moments generated by aligners incorporating divots. The OSIM arch was scanned to generate a. STL version that was modified to create four models by placing divots on different positions of the right central maxillary incisor: GI - divots on gingival-third of lingual surface and incisal-third of labial surface; GM - divots on gingival-third of lingual surface and middle-third of labial surface; MI - divots on middle-third of lingual surface and incisal-third of labial surface; MM - divots on middle-third of lingual surface and middle-third of labial surface. Aligners (n = 30/model) were fabricated using a 0.75 mm thick polyethylene terephthalate material and Biostar® machine following the manufacturer's recommendations. A one-way MANOVA followed by one-way ANOVA (α = 0.05) was utilized to test effect of models on buccolingual force (Fy) and mesiodistal moment (Mx) at 0.20 mm of lingual displacement of the right maxillary central incisor. RESULTS: Mean Mx for GI (-5.68 ± 7.38 Nmm), GM (3.75 ± 5.54 Nmm), MI (-4.27 ± 1.48 Nmm) and MM (1.96 ± 0.99 Nmm) models showed statistical differences between GI and GM, GI and MM, GM and MI and MI and MM. GI exerted the largest Fy (1.87 ± 0.75 N) followed by GM (1.10 ± 0.47 N), MI (0.70 ± 0.23 N) and MM (0.28 ± 0.08 N) with significant differences between GI and GM, GI and MI, GI and MM and GM and MM models. CONCLUSIONS: Vertical divot placement on a right central incisor had a significant effect on aligner biomechanics. Buccolingual forces exerted by models GI, GM and MI were within the range suggested by literature for bodily tooth movement without major root tipping for GM and MI models.

A Scoping Review on Determining Australian Nurse Engagement in Eye Care Settings.

Purpose: As the Australian population grows and ages, the demand for eye care services, and nurses to provide the services, is expected to increase. This will impact nurses, who are Australia's largest health-care provider group. Understanding and mapping the current role and use of nurses in eye care is an essential first step for future health workforce planning and development. To map their engagement, we undertook a scoping review to gain an understanding of the current Australian nurse eye care workforce landscape, to help guide and support future workforce development activities. Secondly, we evaluated if publications in this field incorporated or mentioned the Australian Ophthalmic Nursing Association's National Standards (Practice standards) in their publication. This review also offers other nations and eye care providers the opportunity to evaluate their own health workforce plan and nurse utility. Study Design and Methods: We conducted a review of academic and grey literature, via various search engines, and an inclusion and exclusion criteria. Results: We uncovered 11 publications. Of those, five were academic papers examining extended and advanced nursing practice, one was a letter to the editor, two were industry feature reviews, two were industry reports and the final was the Practice Standards. Key themes throughout indicated the benefit of nurse training and nurse involvement in eye care. Overall, there was insufficient information or data to describe nurse deployment, practice and utility. Finally, the Practice Standards were not referenced in any publication. Conclusion: There is insufficient published information to calculate the level and involvement of nurses, or describe their existing role, advancement or future deployment in eye care in Australia. Without clear information, Australia is unable to develop effective health workforce strategies to attract, train, retain, and appropriately deploy nurses to meet future eye care needs.

Investigating the role of aligner material and tooth position on orthodontic aligner biomechanics.

The primary objective of this work was to investigate the effect of material selection and tooth position on orthodontic aligner biomechanics. Additionally, material property changes with thermoforming were studied to elucidate its role in material performance in-vitro. An orthodontic simulator (OSIM) was used to evaluate forces and moments at 0.20 mm of lingual displacement for central incisor, canine and second premolar using Polyethylene terephthalate (PET), Polyurethane (PU) and Glycol-modified polyethylene terephthalate (PET-G) materials. The OSIM was scanned to generate a model used to fabricate aligners using manufacturer-specified thermoforming procedures. Repeated measures of MANOVA was used to analyze the effect of teeth and material on forces/moments. The role of thermoforming was evaluated by flexural modulus estimated by 3-point bend tests. Pre-thermoformed and post-thermoformed samples were prepared using as-received sheets and those thermoformed over a simplified arch using rectangular geometry, respectively. Groups were compared using Two-way ANOVA. The PET, PU, and PET-G materials exerted maximum buccal force and corresponding moments on the canine. PU exerted more buccal force than PET-G on the canine and second premolar, and more than PET on the second premolar. The impact of thermoforming varied according to the specific polymer: PET-G remained stable, there was a slight change for PET, and a significant increase was noted for PU from pre-thermoformed to post-thermoforming. The results of this study elucidate the influence of material and arch position on the exerted forces and moments. Further, the mechanical properties of thermoplastic materials should be evaluated after thermoforming to characterize their properties for clinical application.

A Comparative Study of Treatment With External Fixator Versus Antibiotic Coated Intramedullary Nail in Infected Non-union Long Bones.

INTRODUCTION: Infected non-union of bones shows problems in providing stability and controlling the infection. The treatment comprises debridement with or without the use of antibiotic cement and achieving stability by either external or internal fixation with or without bone grafting. The use of antibiotic-impregnated cement-coated intramedullary nailing gives stability and treats the infection, thereby permitting early mobilization. External fixation is a definitive mode of fracture stabilization indicated in cases of infected non-unions of the humerus, tibia, and juxta-articular bone. The present study was conducted to compare the results of management of infected non-union long bones treated with an external fixator (Ilizarov and Limb Reconstruction System (LRS)) and vancomycin-coated intramedullary nail. MATERIALS AND METHOD: The present prospective study was conducted on 40 study subjects aged >18 years, and were randomly divided using the alternative method into two groups. Group A: 20 Patients were treated with antibiotic-coated intramedullary interlocking nail (ACIIN). Group B: 20 patients were treated with the external fixator (LRS/Ilizarov). All patients were then evaluated post-operatively using laboratory investigations, and for any sign of inflammation or infection. Results were evaluated using association for the study and application of methods of Ilizarov (ASAMI) scoring system. Data were analyzed using the Statistical Package for Social Sciences (SPSS) version 20 (IBM Corp., Armonk, NY, USA). RESULTS: It was observed that 80.0% of patients in Group A, and 70% of subjects in Group B showed bony union, revealing a statistically significant (p-value<0.05) difference. Infection control, limb length discrepancy, and deformity were also assessed in both groups. Bone and functional outcomes were assessed using the ASAMI score in both groups. In LRS/Ilizarov, it was observed that 55% of subjects had no infection, 15% showed loosening, and 30% had an infection. CONCLUSION: The ACIIN should not be used for bone defects more than 4 cm as it does not achieve stability and for these cases, procedures like external fixators (Ilizarov and LRS) should be used. Antibiotic-coated nail eliminated the complications of the external fixators like pin loosening, and pin infections and was technically less demanding. In our study, stiffness of adjacent joints was more in external fixators (LRS/Ilizarov) than ACIIN.

Design, synthesis and anticancer activity of 2-arylimidazo[1,2-a]pyridinyl-3-amines.

A series of imido-heterocycle compounds were designed, synthesized, characterized, and evaluated for the anticancer potential using breast (MCF-7 and MDA-MB-231), pancreatic (PANC-1), and colon (HCT-116 and HT-29) cancer cell lines and normal cells, while normal cells showed no toxicity. Among the screened compounds, 4h exhibited the best anticancer potential with IC50 values ranging from 1 to 5.5 µM. Compound 4h caused G2/M phase arrest and apoptosis in all the cell lines except MDA-MB-231 mammosphere formation was inhibited. In-vitro enzyme assay showed selective topoisomerase IIα inhibition by compound 4h, leading to DNA damage as observed by fluorescent staining. Cell signalling studies showed decreased expression of cell cycle promoting related proteins while apoptotic proteins were upregulated. Interestingly MDA-MB-231 cells showed only cytostatic effects upon treatment with compound 4h due to defective p53 status. Toxicity study using overexpression of dominant-negative mutant p53 in MCF-7 cells (which have wild type functional p53) showed that anticancer potential of compound 4h is positively correlated with p53 expression.

A Retrospective Observational Study to Compare the Outcome of Various Treatment Modalities of Idiopathic Avascular Necrosis of Hip.

Background: Avascular necrosis (AVN) of hip of the femoral head is increasingly seen in young age, disabling them in their productive years of life. Available treatment options need to be evaluated. Aim: The aim was to compare the outcome of various treatments at different stages of AVN hip. Materials and Methods: A retrospective observational study was done in patients with idiopathic AVN hip, who had undergone different treatment modalities. The data of the included patients at different time intervals were compared. All patients were graded with the help of Harris Hip Score (HHS), and their outcome was evaluated. Results: The age distribution of patients showed that nearly 80% of them were below the age of 50 years. The patients were presenting more often in Ficat and Arlet stage 4 compared to earlier stages. The patients in stage 1 were treated by core decompression alone, which produced good-to-excellent results in 4 of 7 (57.1%) patients. Patients in stage 2 and 3 were treated by core decompression with fibular bone grafting and had good-to-excellent results in 6 of 8 (75%) patients. In stage 4 of disease, cemented total hip replacement (THR) was done, and it produced good-to-excellent results in 13 of 15 (86.6%) patients. Conclusion: In the early stage of disease, core decompression with and without bone grafting produced satisfactory results. In an advanced stage of AVN, THR is an excellent treatment option.

An in vitro evaluation of orthodontic aligner biomechanics around the maxillary arch.

INTRODUCTION: The objective of this study was to evaluate the forces and moments exerted by orthodontic aligners on 3 different displaced maxillary teeth and their adjacent supporting teeth. METHODS: An in vitro orthodontic simulator was used to measure the forces and moments of a 0.75-mm thick glycol-modified polyethylene terephthalate material for 3 maxillary teeth: central incisor, canine, and second premolar. Forces and moments were recorded for tested teeth displaced lingually one by one for 0.20 mm. Repeated measures of multivariate analysis of variance was used to assess the outcome. RESULTS: The mean buccolingual force applied on a displaced canine (2.25 ± 0.38 N) was significantly (P <0.001) more than the central incisor (1.49 ± 0.18 N) and second premolar (1.50 ± 0.16 N). The mean moment (that tends to tip the teeth buccally) exerted on a canine (-20.11 ± 5.27 Nmm) was significantly more (P <0.001) than the central incisor (-8.42 ± 1.67 Nmm) and second premolar (-11.45 ± 1.29 Nmm). The forces and moments acting on teeth adjacent to the displaced tooth were clinically significant and acted in opposing directions to those on the displaced tooth. CONCLUSIONS: The results of this study highlighted that for the same amount of displacement on a given tooth, the forces and moments imposed by the orthodontic aligner depend on location around the arch. These findings highlight the need to further study aligner mechanics around the dental arch and optimize aligner design to impose desired mechanical loads to avoid detrimental effects during orthodontic tooth movement.

The biomechanics of posterior maxillary arch expansion using fixed labial and lingual appliances.

OBJECTIVE: To compare the biomechanics of straight labial, straight lingual, and mushroom lingual archwire systems when used in posterior arch expansion. MATERIALS AND METHODS: An electro-mechanical orthodontic simulator allowing for buccal-lingual and vertical displacements of individual teeth and three-dimensional force/moment measurements was instrumented with anatomically shaped teeth for the maxillary arch. In-Ovation L brackets were bonded to lingual surfaces, and Carriere SLX brackets were bonded to labial surfaces to ensure consistency of slot dimensions. Titanium molybdenum archwires were bent to an ideal arch form, and the teeth on the orthodontic simulator were set to a passive position. Posterior teeth from the canine to second molar were moved lingually to replicate a constricted arch. From the constricted position, the posterior teeth were simultaneously moved until the expansive force decreased below 0.2 N. Initial force/moment systems and the amount of predicted expansion were compared for posterior teeth at a significance level of α = 0.05. RESULTS: Archwire type affected both the expected expansion and initial force/moment systems produced in the constricted position. In general, the lingual systems produced the most expansion. The archwire systems were not able to return the teeth to their ideal position, with the closest system reaching 41% of the intended expansion. CONCLUSIONS: In general, lingual systems were able to produce greater expansion in the posterior regions when compared with labial systems. However, less than half of the intended arch expansion was achieved with all systems tested.

Metabolic Adaptations in Cancer Stem Cells.

Cancer stem cells (CSCs) are a small and elusive subpopulation of self-renewing cancer cells with remarkable ability to initiate, propagate, and spread the malignant disease. In addition, they exhibit increased resistance to anticancer therapies, thereby contributing to disease relapse. CSCs are reported to be present in many tumor types such as melanoma, sarcoma, mammary tumors, colon cancer and other solid tumors. These cells from different tumors show unique energetic and metabolic pathways. For example, CSCs from one type of tumor may predominantly use aerobic glycolysis, while from another tumor type may utilize oxidative phosphorylation. Most commonly these cells use fatty acid oxidation and ketone bodies as the main source of energy production. CSCs have a remarkable ability to reprogram their metabolism in order to survive under adverse conditions such as hypoxia, acidosis, and starvation. There is increasing interest to identify molecular targets that can be utilized to kill CSCs and to control their growth. In this review, we discuss how an understanding of the unique metabolism of CSCs from different tumors can offer promising strategies for targeting CSCs and hence to prevent disease relapse and to treat the metastatic disease.

Anticancer potential of some imidazole and fused imidazole derivatives: exploring the mechanism via epidermal growth factor receptor (EGFR) inhibition.

Imidazole-based epidermal growth factor receptor (EGFR) inhibitors were computationally designed and synthesized. All the compounds were assessed for their anti-proliferative activity against five cancer cell lines, viz., MDA-MB-231 (breast), T47D (breast) and MCF-7 (breast), A549 (lung) and HT-29 (colorectal). Compounds 2c and 2d emerged as better anticancer molecules with no toxicity towards normal cells. 2c and 2d inhibited EGFR enzymatic activity in vitro with IC50 values of 617.33 ± 0.04 nM and 710 ± 0.05 nM, respectively. In order to further improve the potency, we explored an unoccupied area of the ATP binding domain of EGFR and analysed an in silico interaction model of 2c and 2d-EGFR complexes that guided and allowed substitution of the 4-fluorophenyl ring (2c and 2d) with 4-(4-methylpiperazinyl)-3-nitrophenyl at the N-9 position, resulting in compound 3c with a better binding score and potent EGFR inhibitory activity (IC50: 236.38 ± 0.04 nM), which was comparable to the positive control erlotinib (239.91 ± 0.05 nM). 3c exhibited a great improvement in anticancer potency with inhibition of cell growth of all cancer cell lines at very low micromolar concentrations (IC50 = 1.98 to 4.07 µM). Further investigation revealed that 3c also induced an increase in ROS levels in cancer cells in a mitochondrial-independent manner and halted the cell cycle at the sub-G1 phase.

Effectiveness of clear aligner therapy for orthodontic treatment: A systematic review.

OBJECTIVE: To analyse through a systematic review the effectiveness of clear aligners by assessing: (a) predictability of clear aligners and (b) treatment outcome comparison of clear aligner therapy with fixed appliance therapy. METHODS: An electronic search was made from January 2014 to April 2019 using MEDLINE, Embase, Web of Science and LILACS databases without any limitations on language. Three reviewers independently assessed the articles. Quality assessment of observational studies and randomized control trial was done by using the ROBINS tool and Cochrane risk of bias tool, respectively. GRADE instrument was used to assess certainty level for each identified outcome. RESULTS: Seven eligible articles (one randomized controlled trial and six retrospective cohort) were included in our systematic review. Most of the studies (six out of seven) had a moderate risk of bias and one had a high risk of bias. CONCLUSIONS: 'Low to moderate level' of certainty in regard to specific clear aligner therapy tooth movements' efficiency was identified. Clear aligners may produce clinically acceptable outcomes that could be comparable to fixed appliance therapy for buccolingual inclination of upper and lower incisors in mild to moderate malocclusions. However, not all potential clinical scenarios have been assessed in the included studies. Most of the tooth movements may not be predictable enough to be accomplished with only one set of trays with clear aligners despite the recent advances in technology.

A randomized, single-blind, placebo-controlled trial to evaluate the effectiveness of verbal behavior modification and acetaminophen on orthodontic pain.

OBJECTIVES: To evaluate the effectiveness of verbal behavior modification, acetaminophen, and the combined effectiveness of verbal behavior modification along with acetaminophen on orthodontic pain. MATERIALS AND METHODS: One hundred and forty orthodontic fixed appliance patients were randomly assigned to four groups. Group A was administered acetaminophen, group B was given verbal behavior modification, group C was administered acetaminophen as well as verbal behavior modification, and group D was placebo-controlled. A visual analog scale was used to assess pain intensity after 1 week of separator placement. RESULTS: Group A had less mean pain intensity when compared to group B at 6 hours (P < .001) and at 1 (P < .001) and 2 (P = .002) days. Group C patients encountered less mean pain intensity when compared to group B patients at 6 hours (P < .001) and at 1 (P < .001), 2 (P < .001), and 4 (P = .001) days. There was a statistically significant difference between groups A and C (group C experienced less pain intensity) after 6 hours (P = .004) and at day 4 (P = .009) after separator placement. CONCLUSIONS: Acetaminophen is the main agent of orthodontic pain reduction after separator placement, with verbal behavior serving as an adjunct to it.

Role of osteopontin in bone remodeling and orthodontic tooth movement: a review.

In this review, most of the known and postulated mechanisms of osteopontin (OPN) and its role in bone remodeling and orthodontic tooth movement are discussed based on available literature. OPN, a multifunctional protein, is considered crucial for bone remodeling, biomineralization, and periodontal remodeling during mechanical tension and stress (orthodontic tooth movement). It contributes to bone remodeling by promoting osteoclastogenesis and osteoclast activity through CD44- and αvß3-mediated cell signaling. Further, it has a definitive role in bone remodeling by the formation of podosomes, osteoclast survival, and osteoclast motility. OPN has been shown to have a regulatory effect on hydroxyapatite crystal (HAP) growth and potently inhibits the mineralization of osteoblast cultures in a phosphate-dependent manner. Bone remodeling is vital for orthodontic tooth movement. Significant compressive and tensional forces on the periodontium induce the signaling pathways mediated by various osteogenic genes including OPN, bone sialoprotein, Osterix, and osteocalcin. The signaling pathways involved in the regulation of OPN and its effect on the periodontal tissues during orthodontic tooth movement are further discussed in this review. A limited number of studies have suggested the use of OPN as a biomarker to assess orthodontic treatment. Furthermore, the association of single nucleotide polymorphisms (SNPs) in OPN coding gene Spp1 with orthodontically induced root resorption remains largely unexplored. Accordingly, future research directions for OPN are outlined in this review.

Reporting quality of randomized controlled trials in orthodontics--what affects it and did it improve over the last 10 years?

INTRODUCTION: Objectives were to investigate the factors affecting the overall reporting quality and the reporting quality trend of each item over the last 10 years for orthodontic randomized controlled trials (RCTs). MATERIAL AND METHODS: MEDLINE, The Cochrane Library, and EMBASE databases were searched (2003-12) to retrieve studies. Four major orthodontic journals and reference list of included articles were hand searched to identify additional RCTs. The overall reporting quality for all included RCTs (2003-12) was assessed using CONSORT, 2001 (ORQs 2001, score 0-20). In addition, CONSORT, 2010 (ORQs 2010, score 0-27), was used for RCTs published after 2010. Generalized estimated equations (GEEs) model was used for analysis (ORQs 2001 and ORQs 2010). Cochran-Armitage trend test was used to evaluate the reporting quality trend of each individual item based on the CONSORT, 2001. RESULTS: Totally 309 relevant studies were identified, out of which 86 were published after 2010. The median for total ORQs 2001 and ORQs 2010 was 9 (interquartile range 7-12) and 12 (interquartile range 9-15), respectively. Year and journal of publication were significant predictors for both ORQs 2001 and ORQs 2010. Location, sample size, and multicentre trials were significant predictors only for ORQs 2001, and not for ORQs 2010. Trend test showed that reporting quality of four items, namely identification of trial as randomized, sample size, blinding, and randomization has improved significantly with time. CONCLUSION: There is an improvement in the reporting quality. However, it is still suboptimal. To improve the reporting quality, the CONSORT guidelines should be followed strictly.

Treatment planning considerations for molar uprighting.

Molar uprighting cases require individualized treatment planning depending upon condition of ridge, growth pattern of patient, periodontal condition, lower facial height, position of third molar and anchorage. Uprighting of molar was done in two cases--effectively using simple tip back spring in one case and implant in another.

Comparison of the efficacy of chemicomechanical caries removal with conventional methods - a clinical study.

BACKGROUND: There has been considerable interest in developing alternative methods of cavity preparation and caries removal due to disadvantages of using traditional rotating instruments which can result in heat, pressure ,dentin dessication, vibration and pain. Hence, the aim of this study was to compare different methods of caries removal in terms of efficacy, time taken and pain during caries removal. MATERIALS & METHODS: A total of 150 carious teeth were selected among 80 children of 6-10 years of age, following Radiovisiography (RVG) according to specific inclusion criteria and caries removal was done by hand instruments ,air rotor and carisolv respectively. The efficacy, time taken and pain threshold were evaluated during caries removal by Ericson D et al scale, Time scale (Raber H et al), visual analogue scale (Nayak R et al) and verbal pain scale (Cinzia Brunelli et al) respectively. Data was collected and statistically analysed. RESULTS: Mean value of time taken for removal of caries by carisolv group (580.26 sec) was found to be significantly higher as compared to conventional hand excavation and air rotor. Air rotor was found to be the most efficient method (mean value 1.20). Mean value of pain perception was significantly less with carisolv (0.82) as compared to air rotor and hand instrument. CONCLUSION: It was concluded that chemicomechanical removal of caries with Carisolv was found to be effective measure of caries removal and could be considered as viable alternatives to painful procedures like airotor in management of dental caries especially in children. How to cite this article: Goomer P, Jain R L, Kaur H, Sood R. Comparison of the Efficacy of Chemicomechanical Caries Removal with Conventional Methods - A Clinical Study. J Int Oral Health 2013; 5(3):42-47.

Induction of colony-stimulating factors by a 30-kDa secretory protein of Mycobacterium tuberculosis H37Rv.

Colony-stimulating factors (CSFs)-induced increased hematopoietic activity is known to occur in various microbial diseases; however, not much is known during tuberculosis (TB). We investigated the CSF-inducing capability of a Mycobacterium tuberculosis H37Rv component. Swiss mice intravenously injected with purified 30-kDa secretory protein of M. tuberculosis H37Rv (Mtb30; 0.1-10 mg/kg) showed enhanced levels of serum CSFs; maximum response (142 +/- 16 colonies) occurred at 1 mg/kg. In vitro, Mtb30 (1-50 mug/mL) induced mouse peritoneal macrophages (PMs) to elaborate CSFs in the conditioned medium (CM); 25 mug/mL appeared optimal (97 +/- 11 colonies). Both in vivo and in vitro, peak CSF production occurred 24 h after stimulation which levelled-off to background levels by 72 h. Rabbit anti-Mtb30 antibody significantly (p<0.05) reduced CSF production by both Mtb30-stimulated and M. tuberculosis-infected PMs, in vitro. The induced CSFs, both in the serum and CM, appeared to be functionally similar, as they supported the formation of granulocyte (G), monocyte (M) and GM colonies, in similar proportions; the GM colonies were maximum (>79 %). Neutralizing (100%) rabbit anti-mouse interleukin-1 (IL-1) polyclonal antibody did not affect the Mtb30-induced CSF production, indicating it to be IL-1-independent; whereas, CSF production was partly dependent on tumour necrosis factor-alpha (TNF-alpha), as goat anti-mouse TNF-alpha immunoglobulin G only partly inhibited it. Mtb30-induced PM production of CSFs was de novo as it was completely blocked by cycloheximide (50 mug/mL). The CSF-inducing capability of Mtb30 appeared to be proteinaceous in nature as it was heat (70 degrees C; 1 h)-labile, was destroyed by proteases (pronase E and trypsin) and was unaffected by sodium periodate treatment. Further, compared to the controls, Mtb30 induced significantly (p<0.05) high levels of immunoreactive GM-CSF (9+/-1 and 7.5+/-0.8 ng/mL) and M-CSF (4.3+/-0.5 and 3.9+/-0.4 ng/mL) in serum and CM, respectively; G-CSF levels did not increase significantly (p>0.05). Mtb30-treated mice showed a maximum of 2.23- and 2.36-fold increase, in the splenic and femur colony forming unit-GM counts, respectively, as compared to the controls. This is the first report which demonstrates Mtb30-induced production of CSFs that is up-regulated both posttranscriptionally and functionally, and thus adds to our understanding of the molecular pathogenetic mechanisms of TB.