Positional preferences in flavonoids for inhibition of ribonuclease A: Where "OH" where?

Flavonoids are a class of polyphenols that possess diverse properties. The structure-activity relationship of certain flavonoids and resveratrol with ribonuclease A (RNase A) has been investigated. The selected flavonoids have a similar skeleton and the positional preferences of the phenolic moieties toward inhibition of the catalytic activity of RNase A have been studied. The results obtained for RNase A inhibition by flavonoids suggest that the planarity of the molecules is necessary for effective inhibitory potency. Agarose gel electrophoresis and precipitation assay experiments along with kinetic studies reveal Ki values for the various flavonoids in the micromolar range. Minor secondary structural changes of RNase A were observed after interaction with the flavonoids. An insight into the specific amino acid involvement in the binding of the substrate using docking studies is also presented. The dipole moment of the flavonoids that depends on the orientation of the hydroxyl groups in the molecule bears direct correlation with the inhibitory potency against RNase A. The direct association of this molecular property with enzyme inhibition can be exploited for the design and development of inhibitors of proteins.

Evaluation of the Graft Kidney in the Early Postoperative Period: Performance of Contrast-Enhanced Ultrasound and Additional Ultrasound Parameters.

OBJECTIVES: To evaluate the various quantitative parameters of Doppler ultrasound, contrast-enhanced ultrasound (CEUS), and shear wave elastography (SWE) of graft kidneys in the early postoperative period and to explore their utility in the diagnosis of parenchymal causes of graft dysfunction. METHODS: In this ethically approved study, consecutive patients who underwent renal transplantation from March 2017 to August 2018 were recruited, and those with urologic or vascular complications and those who denied consent were excluded. All patients underwent ultrasound with Doppler, SWE, CEUS (using sulfur hexafluoride), and renal scintigraphic examinations 3 to 10 days after transplantation. A composite reference standard was used, including the clinical course, renal function test results, urine output, and histopathologic results for graft dysfunction. Cortical SWE values, quantitative CEUS parameters (generated from a time-intensity curve), and their ratios were analyzed to identify graft dysfunction and differentiate acute tubular necrosis (ATN) from acute rejection (AR). RESULTS: Of the 105 patients included, 19 developed graft dysfunction (18.1%; 12 ATN, 5 AR, and 2 drug toxicity) in the early postoperative period. The peak systolic velocity in the interpolar artery showed a significant difference between control and graft dysfunction groups (P < .001) as well as between ATN and AR (P = .019). Resistive indices and SWE did not show significant differences. Ratios of the time to peak showed a significant difference between control and graft dysfunction groups (P < .05). The rise time and fall time of the large subcapsular region of interest and the rise time ratio were significantly different between ATN and AR (P = .03). CONCLUSIONS: Contrast-enhanced ultrasound can be used to diagnose parenchymal causes of early graft dysfunction with reasonable diagnostic accuracy.

Role of miRNA-182 and miRNA-187 as potential biomarkers in prostate cancer and its correlation with the staging of prostate cancer.

PURPOSE: The microRNAs expression has emerged as a potential biomarker for the diagnosis and prognosis of prostate cancer. This study investigated the expression of miRNA-182 and miRNA-187 in prostate cancer patients and established a correlation between miRNA expression and staging of prostate cancer. MATERIALS AND METHODS: This prospective observational study involved patients undergoing transrectal ultrasound-guided biopsy for suspicion of prostate cancer. Pre-biopsy urine samples and prostatic core tissue samples of the patients were preserved and the miRNA-182 and miRNA-187 were studied. RESULTS: Sixty-three patients were included in this study, thirty-three patients were diagnosed with prostate cancer and thirty patients having benign histopathology were considered as controls. The expression of miRNA-182 was significantly increased (p=0.002) and miRNA-187 significantly decreased (p<0.001) in prostate cancer tissue specimens. However, the expression of these miRNAs did not significantly differ in the urine of prostate cancer patients as compared to controls. Serum Prostatic Specific Antigen (PSA) inversely correlated with the median expression of miR-187 in prostatic tissue (p=0.002). Further, the expression of miRNA-187 in prostate cancer tissue was significantly decreased in metastatic prostate cancer (p=0.037). Using ROC analysis, miRNA-187 expression was able to distinguish the presence or absence of bone metastasis [area under ROC (AUROC) (±SD) was 0.873±0.061, p<0.001]. CONCLUSION: The miRNA-182 and miRNA-187 appear to be promising biomarkers in prostate cancer and miRNA-187 can serve as an important diagnostic marker of metastatic prostate cancer.

Mangiferin attenuates cisplatin-induced acute kidney injury in rats mediating modulation of MAPK pathway.

Cisplatin has been confined due to the reported cases of nephrotoxicity. In the present study, an active xanthone, Mangiferin (from Mangifera indica) was investigated for its defensive role in cisplatin-induced nephrotoxicity. Male wistar albino rats were divided into six groups i.e., group 1 (normal); group 2 (cisplatin control); group 3, 4, and 5 (mangiferin 10, 20, and 40 mg/kg, i.p.); and per se (40 mg/kg; i.p.). The treatment was given for 10 days. On day 7, single dose of cisplatin 8 mg/kg i.p. was administered to induce nephrotoxicity in all groups except normal and per se. On day 11, animals were anesthetized, blood was taken from heart and serum was separated. Thereafter, rats were sacrificed and kidneys were isolated and preserved for histopathological, ultrastructural, immunohistochemical, and western blot analysis. Cisplatin control group showed significant impairment in renal function due to increased inflammation and oxidative stress which was also confirmed by histopathology and MAPK pathway proteins expression. However, pretreatment with mangiferin 20 and 40 mg/kg significantly reversed the renal function along with the structural changes and the levels of antioxidants. Mangiferin treatment attenuated DNA damage and apoptotic pathway.

Biosafety of unmodified ultrafine gold particles (AuPs) upon interacting with human blood components before systemic use.

Ultrafine gold particles (AuPs) can be emerged as a good candidate in the field of drug delivery as well as in imaging applications. However, little attention has been paid to detailed study of nanoparticle's interaction with blood components before systemic use. An investigation into the interaction of ultrafine AuPs with blood components is must for its clinical application. In present study, the interaction of ultrafine sized AuPs (2 ±â€¯0.5 nm, 5 ±â€¯1 nm, and 10 ±â€¯2 nm) with blood components and its immunogenic property (pro-inflammatory reaction) was investigated. All three sized AuPs did not cause any significant hemolysis. Plasma coagulation study showed significant increase in Prothrombin time (PT) with International Normalized Ratio (INR) value raised to 1.53 with 10 nm AuPs. Maximum prolongation of activated partial thromboplastin time (APTT) (3.2 s) was seen with 5 &10 nm sized AuPs. Maximum thrombin time (TT) prolongation was seen with 2 nm (18.3s) with the difference of 1.4 s as compared to control. Platelet aggregation was faster in case of 5 & 10 nm sized AuPs. All three sized AuPs exhibited in-vitro C3 complement activation whereas they did not stimulate significant proliferation of peripheral blood mononuclear cells (PBMC). These findings further validate the utility of ultrafine AuPs for in-vivo applications.

Leishmania donovani reduces the levels of retinoic acid-synthesizing enzymes in infected macrophages and favoring its own survival.

People suffering from malnutrition become susceptible to the infection like Leishmania sp., as it results in a compromised immune response. Retinoic acid (RA), an important constituent of nutrition, shows an immune-modulatory activity. However, its role in the containment of infection is not yet ascertained, particularly in case of visceral leishmaniasis (VL). VL patients (n = 10) and healthy endemic controls (n = 9) were recruited to measure the serum levels of RA. An in vitro model of Leishmania infection using the murine mφ cell line J774.1 was used to investigate the RA-synthesizing enzymes (RALDH-1 and RALDH-2). Parasite loads among infected mφ were measured by quantitative expression of kDNA in the presence of an inhibitor of the RALDH-2 enzyme. We found a significant decrease in the serum levels of RA in VL cases. Importantly, we observed decreased levels of RALDH-1 and RALDH-2 among L. donovani-infected mφ along with simultaneous decrease as well as increase in the Th-1 and Th-2-associated factors, respectively. Furthermore, the pretreatment of mφ with an RALDH-2 inhibitor improved parasite in vitro infection. Our findings show impaired RA pathway among infected mφ and indicate that an intact RA pathway is critical for anti-Leishmania immune response. Graphical abstract ᅟ.

BK polyomavirus and urothelial carcinoma: Experience at a tertiary care centre in India with review of literature.

INTRODUCTION: BK polyomavirus is ubiquitous and remains dormant in the urothelial tract, reactivating and replicating in the immunocompromised state especially in the setting of post-renal transplantation where it is believed to be directly oncogenic based on recent reports. Its oncogenic role in the immunocompetent host is controversial. This study aimed to investigate the association of BK polyomavirus in Urothelial Carcinoma. MATERIAL AND METHODS: Patients with suspected urothelial carcinoma (UC) admitted under Department of Urology over a period of one year were recruited and transuretheral bladder tumor (TURBT) resection was performed, along with sampling of cystoscopically normal-appearing urothelium away from the tumor. In addition, cystectomy specimens with UC were included, with sampling of grossly normal-appearing urothelium away from the tumor. Immunohistochemistry (IHC) for SV40 T-Antigen and chromogenic in situ hybridization (CISH) using BK polyomavirus specific probe was performed on the paired samples (tumor and normal). RESULTS: Twenty-three TURBT and 14 cystectomy specimens were assessed. None of the cases showed evidence of BK polyomavirus infection in tumor or in surrounding mucosa by IHC. CISH performed in ten cases were also found to be negative. In comparison, one post-renal transplant urothelial carcinoma in our experience showed diffuse SV40 staining. CONCLUSIONS: This study suggests that BK polyomavirus infection is not associated with urothelial malignancy in the immunocompetent setting unlike in the immunocompromised setting where it should always be investigated for.

ß-cyclodextrin encapsulated polyphenols as effective antioxidants.

Formation of dityrosine (DT) cross-linkages in proteins is one of the most widely used markers of oxidative stress. Ribonuclease A (RNase A) has 6 Tyr residues and shows a characteristic DT fluorescence peak upon oxidation in addition to major changes in its secondary structure. DT formation can be prevented by using polyphenols (GA, ECG, and EGCG) which are known to have strong antioxidant activity. However, it has been observed that ECG and EGCG initiate protein oligomerization due to protein-polyphenol cross-linkages. To prevent the formation of such cross-linkages we have used ß-cyclodextrin (ß-CD) to encapsulate the polyphenols and studied its antioxidant properties along with that of free polyphenols. The polyphenol/ß-cyclodextrin (ß-CD) inclusion complexes not only prevent DT formation but also reduce protein oligomerization. This may be attributed to the fact that the quinone forming rings of ECG and EGCG become encapsulated in the cavity of ß-CD and are no longer available for protein cross-linking.

Iron oxide labeling does not affect differentiation potential of human bone marrow mesenchymal stem cells exhibited by their differentiation into cardiac and neuronal cells.

Mesenchymal stem cells (MSCs) have shown promising outcomes in cardiac and neuronal diseases. Efficient and noninvasive tracking of MSCs is essential to harness their therapeutic potential. Iron oxide nanoparticles (IONPs) have emerged as effective means to label stem cells and visualize them using magnetic resonance imaging (MRI). It is known that IONPs do not affect viability and cell proliferation of stem cells. However, very few studies have demonstrated differentiation potential of iron oxide-labeled MSCs and their differentiation into specific lineages that can contribute to cellular therapies. The differentiation of IONP-labeled human bone marrow mesenchymal stem cells (hBM-MSCs) into cardiac and neuronal lineages has never been studied. In this study, we have shown that IONP-labeled hBM-MSCs retain their differentiation potential to cardiac and neuronal cell lineages. We also confirmed that labeling hBM-MSCs with IONP does not affect their characteristic properties such as viability, cellular proliferation rate, surface marker profiling, and trilineage differentiation capacity. This study shows that IONP can be efficiently tracked, and its labeling does not alter stemness and differentiation potential of hBM-MSCs. Thus, the labeled hBM-MSCs can be used in clinical therapies and regenerative medicine.

Apigenin ameliorates streptozotocin-induced diabetic nephropathy in rats via MAPK-NF-κB-TNF-α and TGF-ß1-MAPK-fibronectin pathways.

Diabetic nephropathy (DN), a microvascular complication of diabetes, has emerged as an important health problem worldwide. There is strong evidence to suggest that oxidative stress, inflammation, and fibrosis play a pivotal role in the progression of DN. Apigenin has been shown to possess antioxidant, anti-inflammatory, antiapoptotic, antifibrotic, as well as antidiabetic properties. Hence, we evaluated whether apigenin halts the development and progression of DN in streptozotocin (STZ)-induced diabetic rats. Male albino Wistar rats were divided into control, diabetic control, and apigenin treatment groups (5-20 mg/kg po, respectively), apigenin per se (20 mg/kg po), and ramipril treatment group (2 mg/kg po). A single injection of STZ (55 mg/kg ip) was administered to all of the groups except control and per se groups to induce type 1 diabetes mellitus. Rats with fasting blood glucose >250 mg/dl were included in the study and randomized to different groups. Thereafter, the protocol was continued for 8 mo in all of the groups. Apigenin (20 mg/kg) treatment attenuated renal dysfunction, oxidative stress, and fibrosis (decreased transforming growth factor-ß1, fibronectin, and type IV collagen) in the diabetic rats. It also significantly prevented MAPK activation, which inhibited inflammation (reduced TNF-α, IL-6, and NF-κB expression) and apoptosis (increased expression of Bcl-2 and decreased Bax and caspase-3). Furthermore, histopathological examination demonstrated reduced inflammation, collagen deposition, and glomerulosclerosis in the renal tissue. In addition, all of these changes were comparable with those produced by ramipril. Hence, apigenin ameliorated renal damage due to DN by suppressing oxidative stress and fibrosis and by inhibiting MAPK pathway.

Diagnosis of Inherited Epidermolysis Bullosa in Resource-Limited Settings: Immunohistochemistry Revisited.

BACKGROUND: Immunofluorescence (IFM) antigen mapping is the most commonly used technique to diagnose and differentiate epidermolysis bullosa (EB). In India, IFM is limited to few research laboratories and is not readily available, making the diagnosis largely clinical and often inaccurate. Ob jective of the Study: To examine the diagnostic usefulness of immunohistochemistry (IHC) as compared to IFM in resource-limited settings. METHODS: Forty-four consecutive EB patients were included in this study. IHC and IFM were performed on 7-µm frozen tissue sections using standard laboratory protocols with a limited panel of antibodies. The kappa coefficient of agreement was calculated with genetic analysis as the gold standard. RESULTS: IFM and IHC accurately identified the subtype of EB in 80.9% (p < 0.001) of the cases, when a clear blister cavity was evident on biopsy. The sensitivities and specificities of IHC and IFM for diagnosing EB simplex, junctional EB, and dystrophic EB were 100, 100, and 60% and 82.4, 100, and 100%, respectively. IHC was equally effective (p < 0.001) in establishing the type of EB as IFM. CONCLUSIONS: IHC staining and its interpretation were simple and comparable to IFM. IHC had an advantage of showing subtle changes in the epidermal architecture that could not be appreciated on IFM and hence can be considered useful in resource-limited settings.

Molecular mechanisms underlying attenuation of cisplatin-induced acute kidney injury by epicatechin gallate.

Cisplatin, a platinum compound, is used as a first-line agent against various forms of solid cancers. Nephrotoxicity is an important adverse effect of cisplatin therapy, which involves increased oxidative stress, inflammation, apoptosis, and activation of the mitogen-activated protein kinase (MAPK) pathway. It is well known that the bioactive compounds present in green tea are used to treat various disorders due to their biological activities. With this background, the present study was aimed to investigate the effect of epicatechin gallate (ECG), a green tea polyphenol, in cisplatin-induced nephrotoxicity in rats. To achieve this, ECG (1.25, 2.5, and 5 mg/kg; intraperitoneal (i.p.)) was administered to male albino Wistar rats for the period of 10 days. On the 7th day, a single i.p. injection of cisplatin (8 mg/kg) was injected into rats to produce kidney injury and the animals were then killed on the 10th day. Cisplatin toxicity was associated with enhanced oxidative stress, impaired renal function along with marked tubular necrosis in Histopathology. Furthermore, cisplatin activated the MAPK pathway, which contributed to inflammation and apoptosis in the kidney of treated rats. In contrast, ECG (5 mg/kg) pretreatment normalized cisplatin-induced oxidative stress, renal function, and histopathological changes. ECG also prevented the activation of the MAPK pathway, and attenuated inflammation and apoptosis in rats. These findings suggest that ECG prevented cisplatin-induced oxidative stress, inflammation, and apoptosis by downregulating the MAPK pathway and resulted in improved renal function.

Prognostic significance of cytoplasmic p27 in oral squamous cell carcinoma.

OBJECTIVE: p27 is a cell cycle-dependent kinase inhibitor whose presence in nucleus is associated with good prognosis. Recent studies propose that when localized to cytoplasm, it functions as an oncogene and confers a poorer prognosis. This study aimed at analysing the subcellular localization of p27 and its prognostic significance in oral squamous cell carcinomas (OSCCs). METHODS: Immunohistochemistry for p27 was carried out on 60 cases of OSCC (30 cases each of those with lymph node metastasis [LN+ve SCC] and without lymph node metastasis [LN-ve SCC]) and 30 normal mucosa. The relationship between p27 localization and prognosis was analysed statistically. RESULTS: Nuclear immunopositivity was seen in 15%, 23%, 7% and 60%, while cytoplasmic immunopositivity was seen in 80%, 63%, 97% and 43% of all SCC, LN+ve OSCC, LN-ve SCC cases and normal mucosa, respectively. There was a significant inverse correlation between nuclear and cytoplasmic p27 immunopositivity (P = 0.001). Nodal status and tumour stage were the only two parameters that correlated with disease-free survival (DFS) in OSCC cases. However, in LN+ve SCC, a significantly shortened DFS was seen in cases with cytoplasmic p27 expression compared to those without (P = 0.02). Conversely, LN+ve SCC with nuclear p27 had longer DFS on comparison with those without (P = 0.04). CONCLUSIONS: To the best of our knowledge, this is the first study to analyse cytoplasmic localization of p27 in OSCC and correlate with prognosis. Cytoplasmic localization is associated with poor prognosis in OSCC with lymph node metastasis allowing the consideration of cytoplasmic p27 in predicting prognosis and targeted therapeutic approaches.

Monoclonal gammopathy of renal significance with light-chain deposition disease diagnosed postrenal transplant: a diagnostic and therapeutic challenge.

Patients with light-chain deposition disease (LCDD) frequently do not meet criteria for myeloma. In such cases, despite low tumor burden, the circulating monoclonal immunoglobulins cause renal damage, are responsible for post-transplant recurrence, and are rightly categorized as monoclonal gammopathy of renal significance (MGRS) requiring chemotherapy. A 65-year male with uncharacterized nodular glomerulopathy presented with proteinuria 3 years postrenal transplant. His allograft biopsies were diagnostic of light-chain deposition disease (likely recurrent), and in the absence of myeloma, he was labeled as MGRS. Based on the limited literature available, he was treated with bortezomib which resulted in normalization of serum-free light-chain ratios and resolution of proteinuria. He, however, later succumbed to complications of chemotherapy. This case highlights the diagnostic difficulties in LCDD, the importance of an accurate pretransplant diagnosis, and treatment of the malignant clone, in the absence of which post-transplant management of recurrence is challenging with poor outcomes.

Magnetic resonance spectroscopy imaging-directed transrectal ultrasound biopsy increases prostate cancer detection in men with prostate-specific antigen between 4-10 ng/mL and normal digital rectal examination.

OBJECTIVES: To evaluate the ability of magnetic resonance spectroscopic imaging to improve prostate cancer detection rate. METHODS: A retrospective analysis was carried out of 278 men with prostate-specific antigen in the range of 4-10 ng/mL and normal digital rectal examination who underwent transrectal ultrasound-guided prostate biopsy. Outcomes were compared between men who had a standard biopsy versus those who also underwent a prebiopsy magnetic resonance spectroscopic imaging. Men with an abnormal voxel on magnetic resonance spectroscopic imaging had standard transrectal ultrasound biopsies plus biopsies directed to the abnormal voxels. RESULTS: The study group (n = 140) and control group (n = 138) were similar in baseline parameters, such as mean age, prostate size and mean prostate-specific antigen. The overall cancer detection in the magnetic resonance spectroscopic imaging positive group (24.4%) was more than double that of the control group (10.1%). On comparing the magnetic resonance spectroscopic imaging results with the transrectal ultrasound biopsy findings, magnetic resonance spectroscopic imaging had 95.6% sensitivity, 41.9% specificity, a positive predictive value of 24.4%, a negative predictive value of 98% and an accuracy of 51.4%. CONCLUSIONS: Magnetic resonance spectroscopic imaging-directed transrectal ultrasound biopsy increases the cancer detection rate compared with standard transrectal ultrasound biopsy in patients with normal digital rectal examination and elevated prostate-specific antigen in the range of 4-10 ng/mL.

A simple assay for the ribonuclease activity of ribonucleases in the presence of ethidium bromide.

The ribonuclease (RNase) activity of ribonucleases has been assayed by observing the change in fluorescence intensity of ethidium bromide on binding with yeast RNA. The binding of EtBr with RNA was monitored via UV-vis and fluorimetric methods. The degradation of RNA by RNase A was monitored by the change in fluorescence emission intensity of ethidium bromide at 600nm on excitation at 510nm. The ribonucleolytic activity of RNase A and angiogenin at various pH values was determined by this method. From this technique we have also determined the macroscopic pKa values of active site residues of these enzymes. This assay permits the evaluation of the catalytic efficiency of enzymatic proteins ranging from high ribonucleolytic activity to low ribonucleolytic activity toward the natural substrate RNA.

Thrombotic microangiopathy and acute kidney injury following vivax malaria.

BACKGROUND: Infection with Plasmodium vivax, a common human parasite, is occasionally recognized to cause severe organ dysfunction similar to P. falciparum infection. Acute kidney injury (AKI) in malaria is attributed to acute tubular necrosis; thrombotic microangiopathy is not described. METHODS: This observational study includes patients referred to a tertiary care center in North India during June to September 2011 with severe AKI, anemia, and thrombocytopenia following vivax malaria. Renal biopsies were processed by light, immunofluorescence, and electron microscopy. RESULTS: Nine patients (including 5 children) had persistent AKI with thrombocytopenia and variable anemia following the diagnosis of malaria. Based on peripheral smear, eight patients were diagnosed with vivax malaria and had received antimalarial therapy prior to referral; a laboratory diagnosis of P. vivax infection was made for one patient at this center. Renal histology in all cases showed features of thrombotic microangiopathy, including fibrin thrombi, subendothelial widening, and mesangiolysis, along with variable tubulointerstitial nephritis and acute tubular or cortical necrosis. Ultrastructural examination confirmed endothelial injury and subendothelial widening. All patients required hemodialysis, and six were dialysis dependent at four weeks. Delayed presentation to the hospital (P = 0.019), hemolysis on peripheral smear (P = 0.083), and prolonged oligoanuria (P = 0.036) were associated with dialysis dependence. CONCLUSION: The association of anemia, thrombocytopenia, and renal histological evidence of thrombotic microangiopathy with vivax malaria is novel, and suggests the presence of severe endothelial injury. Further studies are necessary to confirm the association and examine the factors associated with its occurrence.