Fatty bone marrow (BM) and defective hematopoiesis are a pathologic hallmark of aplastic anemia (AA). We have investigated adipogenic and osteogenic potential of BM mesenchymal stem cells (BM-MSC) in 10 AA patients (08 males and 02 females) with median age of 37 years (range: 06 to 79 years) and in the same number of age and sex matched controls. It was observed that BM-MSC of AA patients had a morphology, phenotype, and osteogenic differentiation potential similar to control subjects but adipocytes differentiated from AA BM-MSC had a higher density and larger size of lipid droplets and they expressed significantly higher levels of adiponectin and FABP4 genes and proteins as compared to control BM-MSC (P < 0.01 for both). Thus our data shows that AA BM-MSC have enhanced adipogenicity, which may have an important implication in the pathogenesis of the disease.
Poiseuille's equation describes the relationship between fluid viscosity, pressure, tubing diameter, and flow, yet it is not known if cold organ perfusion systems follow this equation. We investigated these relationships in an ex vivo model and aimed to offer some rationale for equipment selection. Increasing the cannula size from 14 to 20 Fr increased flow rate by a mean (SD) of 13 (12)%. Marshall's hyperosmolar citrate was three times less viscous than UW solution, but flows were only 45% faster. Doubling the bag pressure led to a mean (SD) flow rate increase of only 19 (13)%, not twice the rate. When external pressure devices were used, 100 mmHg of continuous pressure increased flow by a mean (SD) of 43 (17)% when compared to the same pressure applied initially only. Poiseuille's equation was not followed; this is most likely due to “slipping” of preservation fluid within the plastic tubing. Cannula size made little difference over the ranges examined; flows are primarily determined by bag pressure and fluid viscosity. External infusor devices require continuous pressurisation to deliver high flow. Future studies examining the impact of perfusion variables on graft outcomes should include detailed equipment descriptions.
In addition to the S-adenosylmethionine decarboxylase (AD) present in all organisms, trypanosomatids including Leishmania spp. possess an additional copy, annotated as the putative S-adenosylmethionine decarboxylase-like proenzyme (ADL). Phylogenetic analysis confirms that ADL is unique to trypanosomatids and has several unique features such as lack of autocatalytic cleavage and a distinct evolutionary lineage, even from trypanosomatid ADs. In Trypanosoma ADL was found to be enzymaticaly dead but plays an essential regulatory role by forming a heterodimer complex with AD. However, no structural or functional information is available about ADL from Leishmania spp. Here, in this study, we report the cloning, expression, purification, structural and functional characterization of Leishmania donovani (L. donovani) ADL using biophysical, biochemical and computational techniques. Biophysical studies show that, L. donovani ADL binds S-adenosylmethionine (SAM) and putrescine which are natural substrates of AD. Computational modeling and docking studies showed that in comparison to the ADs of other organisms including human, residues involved in putrescine binding are partially conserved while the SAM binding residues are significantly different. In silico protein-protein interaction study reveals that L. donovani ADL can interact with AD. These results indicate that L. donovani ADL posses a novel substrate binding property and may play an essential role in polyamine biosynthesis with a different mode of function from known proteins of the S-adenosylmethionine decarboxylase super family.
Luminescent microspheres encapsulating glucose oxidase have recently been developed as implantable glucose sensors. Previous work has shown that the response range and sensitivity can be tuned by varying the thickness and composition of transport-controlling nanofilm coatings. Nevertheless, the linear response range of these sensors falls significantly below the desired clinical range for in vivo monitoring. We report here an alternative means of tuning the response range by adjusting microsphere porosity. A reaction-diffusion model was first used to evaluate whether increased porosity would be expected to extend the response range by decreasing the flux of glucose relative to oxygen. Sensors exhibiting linear response (R2>0.90) up to 600 mg/dL were then experimentally demonstrated by using amine-functionalized mesoporous silica microspheres and polyelectrolyte nanofilm coatings. The model was then used for sensor design, which led to the prediction that sensors constructed from ~12 μm microspheres having an effective porosity between 0.005 and 0.01 and ~65 nm transport-limiting coatings would respond over the entire physiological glucose range (up to 600 mg/dL) with maximized sensitivity.
Glucose; biosensors; luminescence; microparticles; layer-by-layer self assembly; reaction-diffusion system
AIM: To compare the phenotypic and neural differentiation potential of human bone marrow derived multipotent adult progenitor cells (MAPC) and mesenchymal stem cells (MSC).
METHODS: Cultures of MAPC and MSC were established in parallel from same samples of human bone marrow (n = 5). Both stem cell types were evaluated for expression of pluripotency markers including Oct-4 and Nanog by immunocytochemistry and reverse-transcription polymerase chain reaction (RT-PCR) and expression of standard mesenchymal markers including CD14, CD34, CD44, CD45, CD73, CD90, CD105 and human leukocyte antigen (HLA)-ABC by flow cytometry. After treatment with neural induction medium both MAPC and MSC were evaluated for expression of neural proteins [neuronal filament-200 (NF-200) and glial fibrillar acidic protein (GFAP)] by immunocytochemistry and Western blotting and neural genes [NF-200, GFAP, Tau, microtubule-associated protein (MAP)-1B, MAP-2, neuron-specific enolase (NSE) and oligodendrocyte-1 (Olig-1)] by quantitative real-time-PCR.
RESULTS: MAPC had small trigonal shaped while MSC had elongated spindle-shaped morphology. The MAPC expressed Oct-4 and Nanog both at gene and protein levels, whereas MSC were negative for these pluripotent markers. MAPC were negative for HLA-ABC while MSC had high expression of HLA-ABC. In addition, MAPC as compared to MSC had significantly lower expression of CD44 (36.56% ± 1.92% vs 98.23% ± 0.51%), CD73 (15.11% ± 2.24% vs 98.53% ± 2.22%) and CD105 (13.81% ± 3.82% vs 95.12% ± 5.65%) (P < 0.001, for all) MAPC cultures compared to MSC cultures treated with neural induction medium had significantly higher fold change expression of NF-200 (0.64), GFAP (0.52), Tau (0.59), MAP-2 (0.72), Olig-1 (0.18) and NSE (0.29) proteins (P < 0.01 for Olig-1 and P < 0.001 for rest) as well as higher fold change expression of genes of NF-200 (1.34), GFAP (1.12), Tau (1.08), MAP-1B (0.92), MAP-2 (1.14) and NSE (0.4) (P < 0.001 for all).
CONCLUSION: MAPC can be differentially characterized from MSC as Oct-4 and Nanog positive stem cells with no expression of HLA-ABC and low expression of mesenchymal markers CD44, CD73 and CD105 and when compared to MSC they possess greater predilection for differentiation into neuro-ectodermal lineage.
Bone marrow; Human multipotent adult progenitor cells; Human mesenchymal; Stem cells; Phenotypic markers; Neural differentiation
The aim of the proposed research work was to develop a novel dual-compartment capsule (NDCC) with polymeric disc for gastroretentive dosage form, which will ultimately result in better solubility and bioavailability of Ofloxacin. Floating ring caps were formulated by using different natural polymers, separating ring band and swellable polymer located at the bottom of capsule. Formulated ring caps were assessed for coating thickness, In vitro buoyancy, In vitro drug release, release kinetics and stability studies. Coating attained by the capsule shell was found to be 0.0643 mm. Depending on nature of natural polymer used, most of the formulations showed buoyancy for more than 9 hrs. Developed formulation demonstrated considerably higher drug release up to 9 hrs. The developed formulation FE2 depicted the drug release according to Korsmeyer-Peppas model. There was not any significant change in performance characteristics of developed ring caps after subjecting them to stability studies. The present study suggests that the use of NDCC for oral delivery of Ofloxacin could be an alternative to improve its systemic availability which could be regulated by the floating approach. The designed dosage system can have futuristic applications over payloads which require stomach-specific delivery.
Triplex-forming oligonucleotides (TFOs) represent an antigene approach for gene regulation through direct interaction with genomic DNA. While this strategy holds great promise owing to the fact that only two alleles need silencing to impact gene regulation, delivering TFOs to target cells in vivo is still a challenge. Our recent efforts have focused on conjugating TFOs to carrier molecules like cholesterol to enhance their cellular uptake and mannose-6-phosphate-bovine serum albumin (M6P-BSA) to target TFO delivery to hepatic stellate cells (HSCs) for treating liver fibrosis. These approaches however are rendered less effective owing to a lack of targeted delivery, as seen with lipid-conjugates, and the potential immune reactions due to repeated dosing with high molecular weight BSA conjugated TFO. In this review, we discuss our latest efforts to enhance the effectiveness of TFO for treating liver fibrosis. We have shown that conjugation of TFOs to M6P-HPMA can enhance TFO delivery to HSCs and has the potential to treat liver fibrosis by inhibiting collagen synthesis. This TFO conjugate shows negligible immunogenicity owing to the use of HPMA, one of the least immunogenic copolymers, thereby making it a suitable and more effective candidate for antifibrotic therapy.
Bioconjugation; HPMA; TFO; liver fibrosis
Prospective study with simple randomization.
To evaluate the results of anterior spinal instrumentation, debridement and decompression of cord and compare it with results of a similar procedure done without the use of anterior instrumentation.
Overview of Literature
Use of anterior spinal instrumentation in treatment of tubercular spondylitis is still an infrequently followed modality of treatment and data regarding its usefulness are still emerging.
Thirty-two patients of tubercular paraplegia with involvement of dorsal and dorso-lumbar vertebrae were operated with anterior spinal cord decompression, autofibular strut grafting with anterior instrumentation in 18 patients and no implant in 14 patients. Results were compared on the basis of improvement in Frankel grade, correction of local kyphosis, decrease in canal compromise and further progression of kyphosis.
The mean local kyphosis correction in the immediate postoperative period was 24.1° in the instrumented group and was 6.1° in the non instrumented group. The mean late loss of correction of local kyphosis at 3 years follow-up was 1.7° in the instrumented and 6.7° in the non instrumented group. The mean improvement in canal compression was 39.5% in the instrumented group and 34.8% in the non instrumented group.
In treatment of tubercular spondylitis by anterior debridement and decompression of the spinal cord and autofibular strut grafting, the use of instrumentation has no relation with the improvement in neurological status, however the correction of local kyphosis and prevention of further progression of local kyphosis was better with the use anterior spinal instrumentation.
Tuberculosis; Instrumentation; Kyphosis; Paraplegia
Many prostate cancers relapse due to the generation of chemoresistance rendering first-line treatment drugs like paclitaxel (PTX) ineffective. The present study aims to determine the role of miRNAs and Hedgehog (Hh) pathway in chemoresistant prostate cancer and to evaluate the combination therapy using Hh inhibitor cyclopamine (CYA). Studies were conducted on PTX resistant DU145-TXR and PC3-TXR cell lines and clinical prostate tissues. Drug sensitivity and apoptosis assays showed significantly improved cytotoxicity with combination of PTX and CYA. To distinguish the presence of cancer stem cell like side populations (SP), Hoechst 33342 flow cytometry method was used. PTX resistant DU145 and PC3 cells, as well as human prostate cancer tissue possess a distinct SP fraction. Nearly 75% of the SP cells are in the G0/G1 phase compared to 62% for non-SP cells and have higher expression of stem cell markers as well. SP cell fraction was increased following PTX monotherapy and treatment with CYA or CYA plus PTX effectively reduced their numbers suggesting the effectiveness of combination therapy. SP fraction cells were allowed to differentiate and reanalyzed by Hoechst staining and gene expression analysis. Post differentiation, SP cells constitute 15.8% of total viable cells which decreases to 0.6% on treatment with CYA. The expression levels of P-gp efflux protein were also significantly decreased on treatment with PTX and CYA combination. MicroRNA profiling of DU145-TXR and PC3-TXR cells and prostate cancer tissue from the patients showed decreased expression of tumor suppressor miRNAs such as miR34a and miR200c. Treatment with PTX and CYA combination restored the expression of miR200c and 34a, confirming their role in modulating chemoresistance. We have shown that supplementing mitotic stabilizer drugs such as PTX with Hh-inhibitor CYA can reverse PTX chemoresistance and eliminate SP fraction in androgen independent, metastatic prostate cancer cell lines.
Injudicious reaming of the tibial shaft can lead to extreme local hyperthermia, which in turn can result in the rare but catastrophic complication of segmental bone and soft tissue necrosis (osteocutaneous thermal necrosis). This is a retrospective study showing osteocutaneous thermal necrosis occurring after tibial intramedullary reaming salvaged by Ilizarov reconstruction in seven patients from the collective experience of four limb reconstruction centres. All patients were males, with an average age of 51.8 years (range, 30–70 years), who had undergone intramedullary reaming during the treatment of closed tibial fractures. In all patients, circumferential bone and variable contiguous soft tissue necrosis developed a few days after reaming. Bone and soft tissue reconstruction was subsequently performed using a circular external fixator (Ilizarov apparatus or Taylor spatial frame) a mean of four months after injury in six patients; in one case, reconstruction was undertaken four years after the original injury. Two complications (secondary tissue breakdown at a bone transport site; premature consolidation) necessitated cessation of bone transport at one of two bone transport levels in two patients. All patients eventually healed with a good functional result after an average of 11.5 months in the fixator (range, 10–13 months).
There is inconsistency in accepting waist circumference (WC) as mandatory and also regarding its significance for diagnosis of metabolic syndrome (MetS) for different populations.
To study the association of individual parameters of MetS with WC cutoffs suitable for South Asian Indians.
Materials and Methods:
From an ongoing hospital-based study on MetS as per the criteria of diagnosis of modified NCEP ATP III, 713 subjects having a minimum three of the four parameters, i.e., dyslipidemia [low high density lipoprotein (HDL), high triglycerides], dysglycemia and hypertension, without regard to cutoffs of WC, were included in the present study.
Receiver operator characteristic curve analysis of WC cut-off points for males was 90 cm with a sensitivity and specificity of 71% and 96%, respectively, and for females was 85 cm with a sensitivity and specificity of 86% and 93%, respectively, associated with the risk factors of MetS. Multiple logistic regression analysis for low density lipoprotein (LDL) cholesterol concentration of ≥3.38 mmol/l showed an odds ratio of 5.03 (95% CI = 1.29–19.5) in males and 3.17 (95% CI = 1.14–8.76) in females which was statistically significant (P < 0.02); in addition to higher WC, higher level of triglyceride (P ≤ 0.0001) and lower level of high density lipoprotein cholesterol (P ≤ 0.02) were observed.
This study suggests that WC of 90 cm in males and 85 cm in females should be a mandatory criterion of MetS in our subset of population. LDL may be considered one of the components of MetS along with the currently defined WC cutoffs.
Asian Indians; low density lipoprotein cholesterol; metabolic syndrome; receiver operator characteristic curve; waist circumference
1–naphthol (1N), 2–naphthol (2N) and 8–quinolinol (8H) are general water pollutants. 1N and 2N are the configurational enantiomers and 8H is isoelectronic to 1N and 2N. These pollutants when ingested are transported in the blood by proteins like human serum albumin (HSA). Binding of these pollutants to HSA has been explored to elucidate the specific selectivity of molecular recognition by this multiligand binding protein. The association constants (Kb) of these pollutants to HSA were moderate (104–105 M−1). The proximity of the ligands to HSA is also revealed by their average binding distance, r, which is estimated to be in the range of 4.39–5.37 nm. The binding free energy (ΔG) in each case remains effectively the same for each site because of enthalpy–entropy compensation (EEC). The difference observed between ΔCpexp and ΔCpcalc are suggested to be caused by binding–induced flexibility changes in the HSA. Efforts are also made to elaborate the differences observed in binding isotherms obtained through multiple approaches of calorimetry, spectroscopy and bioinformatics. We suggest that difference in dissociation constants of pollutants by calorimetry, spectroscopic and computational approaches could correspond to occurrence of different set of populations of pollutants having different molecular characteristics in ground state and excited state. Furthermore, our observation of enhanced binding of pollutants (2N and 8H) in the presence of hemin signifies that ligands like hemin may enhance the storage period of these pollutants in blood that may even facilitate the ill effects of these pollutants.
The bipolar hip prostheses after some time functions as a unipolar device. There is a need to change the design of bipolar hip prostheses to make it function as a bipolar device over a prolonged period of time. A bicentric bipolar hip prosthesis was used as an implant for various conditions of the hip. We evaluated the movement of this newly developed prosthesis at the interprosthetic joint radiologically at periodic intervals.
Materials and Methods:
Fifty two cases were operarted with the Bicentric bipolar prosthesis for indications like fracture neck of femur and various other diseases of the hip and were followed up with serial radiographs at periodic intervals to evaluate, what fraction of the total abduction at the hip was occurring at the interprosthetic joint.
In cases of intracapsular fracture neck of femur, the percentage of total abduction occurring at the interprosthetic joint at 3 months follow-up was 33.74% (mean value of all the patients), which fell to 25.66% at 1.5 years. In indications for bipolar hemireplacement other than fracture neck of femur, the percentage of total abduction occurring at the interprosthetic joint at 3 months follow-up was 71.71% (mean value) and at 1.5 years it was 67.52%.
This study shows the relative preservation of inner bearing movement in the bipolar hip prosthesis with time probably due its refined design. Further refinements are needed to make the prosthesis work better in patients of intracapsular fracture neck femur.
Bicentric bipolar prosthesis; inner bearing; interprosthetic joint
The case of a 20-year-old female who presented with refractory coccydynia and sternal pain is described. She was immunocompetent, and had no systemic features. She was diagnosed with tuberculosis of the sternal and coccygeal regions based on magnetic resonance imaging and histopathology of biopsy specimens. Conservative management with oral multidrug antituberculous therapy completely cured the patient, and she had not suffered any recurrence after three years of follow-up. This case highlights the possibility of the multicentric presentation of tuberculosis at two rare sites in the same immunocompetent patient, even though the differential diagnosis was coccydynia.
Tuberculosis; Immunocompetent; Coccyx; Sternum
A facile synthesis of azabicycloadducts is described by 1,3-dipolar cycloaddition reactions of thioisatin with thiazolidine-2-carboxylic acid in the presence of various electron rich and electron deficient dipolarophiles. Theoritical calculations have been performed to study the regioselectivity of products. The geometrical and energetic properties have been analyzed for the different reactants, transition states and cycloadducts formed.
Azabicycloadducts; 1,3-Dipolar cycloaddition reactions; AM1 Calculations; Thioisatin; Thiazolidine-2-carboxylic Acid
A retrospective cohort study.
To analyze differences in between the unipedicular vs. bipedicular balloon kyphoplasty for the treatment of multiple myeloma lesions.
Overview of Literature
Both vertebroplasty and kyphoplasty are reported to be effective for the treatment of vertebral compression fractures in multiple myeloma patients. Kyphoplasty is often performed with a bipedicular approach while vertebroplasty with a monopedicular approach. Monopedicular kyphoplasty is investigated as a viable surgical technique alternatively in comparison with the bipedicular method.
We performed 37 vertebral body augmentation procedures, 18 vertebroplasty (group A) and 19 kyphoplasty, 9 unipedicular approaches (group B1) and 10 bipedicular approaches (group B2), on 14 patients affected by multiple myeloma with a mean clinical and radiographic follow up of more than 12 months.
Both kyphoplasty techniques lead to a better postoperative improvement of the vertebral height and kyphotic deformity if compared with the vertebroplasty, with a statistical significance for the body height restoration only (p = 0.0066). The unipedicular and the bipedicular kyphoplasty have similar results in term of kyphotic deformity correction and height restoration. The 85.7% (12/14) of the patients had an immediate improvement of the pain and no difference between the vertebroplasty and kyphoplasty groups were observed regarding the pain. We observed a 24.3% of cement leakage in all groups with no clinical symptoms and noticed that the risk of extravasations was higher in multilevel treatment, in bipedicular kyphoplasty procedures and in patients not treated previously with a bone marrow transplant.
Both vertebroplasty and kyphoplasty are effective in treating vertebral compression fracture due to multiple myeloma. Unipedicular kyphoplasty could give equivalent results as with bipedicular kyphoplasty in multilevel disease, aiming only to restore the sagittal alignment of the spine and the height of the vertebral body especially at the thoracolumbar spinal segment.
Unipedicular; Kyphoplasty; Vertebroplasty; Multiple myeloma
This case report describes a rare and unusual lesion found in a 33-year-old male, which was diagnosed as pleomorphic adenoma of the minor salivary glands in the upper lip. The tumor was a circumscribed, large firm mass, about 3 cm in diameter, almost obstructing the nares and characterized by slow growth. Complete excision was performed and the histopathologic analysis showed pleomorphic adenoma. The tumor did not recur. A brief review of the relevant literature is also presented.
Minor salivary gland tumors; pleomorphic adenoma; upper lip
Formation of the mammalian orofacial region involves multiple signaling pathways regulating sequential expression of and interaction between molecular signals during embryogenesis. The present study examined the expression patterns of members of the MAPK family in developing murine orofacial tissue.
Total RNA was extracted from developing embryonic orofacial tissue during gestational days (GDs) 12–14 and used to prepare biotinylated cDNA probes, which were then denatured and hybridized to murine MAP kinase signaling pathways gene arrays.
Expression of a number of genes involved in the (ERK1/2) cascade transiently increased in the embryonic orofacial tissue over the developmental period examined. Numerous members of the SAPK/JNK cascade were constitutively expressed in the tissue. Genes known to play a role in p38 MAPK signaling exhibited constitutive expression during orofacial development. Western blot analysis demonstrated that ERK2/1, p38 and SAPK/JNK kinases are present in embryonic orofacial tissue on each of GD 12, 13 and 14. By using phospho-specific antibodies, active ERK was shown to be temporally regulated during orofacial development. Minimal amounts of active p38 and active SAPK/JNK were detected in orofacial tissue during GDs 12–14.
Our study documents specific expression patterns of genes coding for proteins belonging to the ERK1/2, p38 and SAPK/JNK MAP kinase families in embryonic orofacial tissue. We also demonstrate that active, phosphorylated forms of ERK1/2 only, were detected in the embryonic tissue investigated, suggesting a more central role for members of this family in embryonic orofacial development.
embryonic; palate; MAP kinase; orofacial; ERK
A 23-year-old woman presented with large exophytic genital wart arising from perineum, vulva, introitus of the vagina, and inner aspect of thighs. Patient developed severe itching and formication (insect-crawling sensation) in the lesions for past 1 week, though careful examination did not reveal any insects. Considering that the disease was causing psychological stress and physical symptoms, radiofrequency excision was planned. However, during the procedure, several maggots appeared from the crypts. The procedure was abandoned and maggots were removed manually. Subsequently external giant warts were removed using radiofrequency device. There was no recurrence of excised warts during 3 month follow-up. To our knowledge, this is the second reported case of maggots in genital warts.
Genital warts; myiasis; radiofrequency excision
Standardization is essentially a measure for ensuring the quality control of herbal drugs. But the gender of the plant affecting the quality of crude drugs does not appear to have been taken care of so far. Today, sophisticated modern research tools for the evaluation of the plant drugs are available but the microscopic method is one of the simplest and cheapest methods.
Methods and Materials:
The pharmacognostic investigation of the fresh, powdered, and anatomical sections of the female leaves of Trichosanthes dioica Roxb. was carried out to determine its bioprospective constants.
Results and Discussion:
Externally, the leaves possess a cordate base, a sinuate and dentate margin, an acute to acuminate apex, and both surfaces are very rough with rigid hair surface. Internally, it shows the presence of anomocytic stomata, unicellular, and both glandular and simple covering trichomes scattered as such throughout or attached with the cells of the epidermis. Majority of the glandular trichomes are with a four-to-five-celled uniseriate stalk and unicellular head; very few are short and with uni- to bicellular stalk and uni- to multicellular head especially from that of the petiole region. Simple covering, multicellular, uniseriate thick-walled trichomes are of various sizes. Usually cells of both simple and glandular trichomes are often embedded with cystolith. Phytochemical studies of the powdered leaves revealed the presence of alkaloids, resins, glycosides, flavonoids and some carbohydrates. The pharmacognostic profile of the leaves will assist in the standardization for quality, purity, and sample identification.
Female leaf morphology; pharmacognostic standardization; Trichosanthes dioica
Luminescent microspheres encapsulating glucose oxidase have recently been reported as potential implantable sensors, but the operational lifetime of these systems has been limited by enzyme degradation. We report here that the longevity of these enzymatic microparticle-based sensors has been extended by the coimmobilization of glucose oxidase (GOx) and catalase (CAT) into the sensor matrix. A mathematical model was used to compare the response and longevity of the sensors with and without catalase. To experimentally test the longevity, sensors were continuously operated under normoglycemic dermal substrate concentrations and physiological conditions (5.5 mM glucose and 140 µM O2, 37°C and pH 7.4). The sensors incorporating CAT were experimentally shown to be ~5 times more stable than those without CAT; nevertheless, the response of sensors with CAT still changed by approximately 20%, when operated continuously for seven days. The experimentally-determined trends obtained for the variation in sensor response due to enzyme deactivation were in close agreement with modeling predictions, which also revealed a significant apparent loss in enzyme activity upon immobilization. It was further predicted via modeling that by incorporating 0.1 mM each of active GOx and CAT, the sensors will exhibit less than 2% variation in response over one month of continuous operation.
Glucose; biosensors; luminescence; microparticles; finite element modeling; layer-by-layer self assembly
Arsenic is a ubiquitous element that is a potential carcinogen and teratogen and can cause adverse developmental outcomes. Arsenic exerts its toxic effects through the generation of reactive oxygen species (ROS) that include hydrogen peroxide (H2O2), superoxide-derived hydroxyl ion, and peroxyl radicals. However, the molecular mechanisms by which arsenic induces cytotoxicity in murine embryonic maxillary mesenchymal (MEMM) cells are undefined.
MEMM cells in culture were treated with different concentrations of pentavalent sodium arsenate [As (V)] for 24 or 48 hours and various end points measured.
We show that treatment of MEMM cells with the pentavalent form of inorganic arsenic resulted in caspase-mediated apoptosis, accompanied by generation of ROS and disruption of mitochondrial membrane potential. Treatment with caspase inhibitors markedly blocked apoptosis. In addition, the free radical scavenger N-acetylcysteine dramatically attenuated arsenic-mediated ROS production and apoptosis, and exposure to arsenate increased Bax and decreased Bcl protein levels in MEMM cells.
Taken together, these findings suggest that in MEMM cells, arsenate-mediated oxidative injury acts as an early and upstream initiator of the cell death cascade, triggering cytotoxicity, mitochondrial dysfunction, altered Bcl/Bax protein ratios, and activation of caspase-9.
Reactive oxygen species; arsenate; mitochondria; apoptosis; caspases