Electronic characteristics of BRCA1 mutations in DNA.

The efficient and low-cost way for gene mutation detection and identification are conducive for the detection of disease. Here, we report the electronic characteristics of the gene of breast cancer 1 in four common mutation types: duplication, single nucleotide variant, deletion, and indel. The electronic characteristics are investigated by the combination of density functional theory and non-equilibrium Green's function formulation with decoherence. The magnitude of conductance of these DNA molecules and mutational changes are found to be detectable experimentally. In this study, we also find the significant mutation type dependent on the change of conductance. Hence these mutations are expected to be identifiable. We find deletion type mutation shows the largest change in relative conductance (~97%), whereas the indel mutation shows the smallest change in relative conductance (~27%). Therefore, this work presents a possibility of electronic detection and identification of mutations in DNA, which could be an efficient method as compared to the conventional methods.

Effect of cytosine hydroxymethylation on DNA charge transport.

DNA hydroxymethylation plays a very important role in some biological processes, such as DNA methylation process. In addition, its presence can also cause some diseases. In this paper, the electrical properties of cytosine hydroxymethylated (Chm) DNA sequences are studied. The density functional theory (DFT) and Landauer-Büttiker framework are used to study the decoherence conductance and transmission of the Chm strands in different configurations, which provides a theoretical basis for the detection of Chm. The results show that the conductance of the hydroxymethylated DNA strand is smaller than that of the native and methylated strands. The length dependence of the Chm strands is also studied. With the length increasing, the conductance becomes larger. This study shows that DNA methylation can be detected electrically.

Implications of a conserved region of bluetongue virus protein VP2 in cross-neutralisation of bluetongue virus serotypes.

Bluetongue (BT) is a vector-borne disease of ruminants caused by Bluetongue virus (BTV). Twenty-nine different serotypes of BTV are currently reported throughout the world. The main objective of this study is the development of a subunit vaccine model that could potentially be adapted to provide broad spectrum protection against multiple BTV serotypes, which the conventional vaccines fail to address. To this end, three different BTV proteins (conserved region of viral protein [VP]2, VP5 and NS1) were expressed and purified in an Escherichia coli expression system. The immunogenicity of these proteins was tested in murine models using the MontanideTM ISA 201 VG adjuvant. BALB/c mice were immunised thrice (with individual proteins and a mixture of three proteins) at two-week intervals and were monitored until Day 40 post-infection/vaccination. Protein-specific antibodies directed against the recombinant proteins were detected by indirect enzyme-linked immunosorbent assay. Neutralising antibody (Nab) titres and cross-neutralisation against a range of BTV serotypes (BTV-1, -2, -4, -5, -9, -10, -12, -16, -21, -23 and -24) were determined by serum neutralisation test. The recombinant proteins elicited higher Nab titres compared with the inactivated vaccine group, except for BTV-1, where the inactivated vaccine group elicited higher Nab titres. Additive effect of the three proteins was not observed as the Nab titres generated with a combination of conserved VP2, VP5 and NS1 was similar to those of the individual protein groups. Whilst BTV-12 could only be neutralised by serum raised against the inactivated vaccine group, BTV-5 and -24 could not be neutralised by any of the groups tested. Our cumulative data suggest that the conserved regions of VP2 (cVP2), VP5 and NS1 could play an important part in the novel vaccine design against multiple BTV serotypes. Importantly, given that VP2 was already known to elicit a serotype-specific immune response against BT, we report, for the first time, that the conserved region of VP2 has the ability to induce cross-protective immune response.

Predictors for severe hemorrhage requiring angioembolization post percutaneous nephrolithotomy: A single-center experience over 3 years.

CONTEXT AND AIM: About 1% of the patients undergoing percutaneous nephrolithotomy (PCNL) have bleeding severe enough to require angioembolization. We identified factors which could predict severe bleeding post-PCNL and reviewed patients who underwent angioembolization for the same. SETTINGS AND DESIGN: This is a single-institutional, retrospective study over a period of 3 years. SUBJECTS AND METHODS: We retrospectively studied 583 patients undergoing PCNL at our institute from 2013 to 2016. We analyzed nine patients (three from our institute and six referred patients) who underwent angioembolization for severe bleeding post-PCNL. We analyzed the preoperative characteristics, intraoperative findings, and postoperative course of these patients and compared this with those patients who did not have a severe post-PCNL bleeding. STATISTICAL ANALYSIS USED: Fischer's exact test and Chi-square test were used in univariate analysis. Logistic regression analysis was used in multivariate analysis with a value of P < 0.05 considered statistically significant. RESULTS: Three of the 583 patients (0.51%) who underwent PCNL at our institute required embolization to control bleeding. Preoperative characteristics that were significant risk factors for severe bleeding were a history of ipsilateral renal surgery (P = 0.0025) and increased stone complexity (P = 0.006), while significant intraoperative factors were injury to the pelvicalyceal system (P = 0.0005) and multiple access tracts (P = 0.022). Angiography revealed arteriovenous fistula in two patients and a pseudoaneurysm in seven patients. All patients underwent successful superselective angioembolization with preserved renal perfusion in six patients on control angiography postembolization. CONCLUSIONS: History of ipsilateral renal surgery, increased stone complexity, multiple access tracts, and injury to the pelvicalyceal system are risk factors predicting severe renal hemorrhage post-PCNL. Early angiography followed by angioembolization should be performed in patients with severe post-PCNL bleeding who fail to respond to conservative measures.

Infection kinetics and antibody responses in Deccani sheep during experimental infection and superinfection with bluetongue virus serotypes 4 and 16.

AIM: The current study was designed to understand the infection kinetics and antibody responses of major circulating serotypes of bluetongue virus (BTV) in India, i.e., BTV-4 and BTV-16 through experimental infection and superinfection of Deccani sheep, a popular breed of sheep found in the southern states of India. MATERIALS AND METHODS: Experimental infection with 106 TCID50/ml BTV-4 was followed by superinfection with BTV-16 and vice versa. Along with observing for clinical signs and immunological responses in the experimentally infected sheep, the effect of infection of one specific serotype on the outcome of superinfection with a different serotype was also studied. RESULTS: Certain interesting findings have been made in the course of experimental infection, such as prominent signs of infection in BTV-4 infection, mild or no clinical signs in BTV-16-infected and superinfected animals, and non-seroconversion of one of the BTV-16-superinfected animals. In addition, BTV was isolated from infected sheep in all the experimental conditions except BTV-16 superinfection. Furthermore, it was observed that immune response in the form of type-specific antibodies was slower with BTV-16 superinfection. CONCLUSION: Superinfection of a sheep with more than one serotype of BTV is a common phenomenon in BT endemic countries like India. Such situation was replicated in an experimental infection in the current study, and the findings to our knowledge are first of a kind and are likely to aid in unfolding the newer aspects of BTV pathogenesis and virulence.

Standardization and application of real-time polymerase chain reaction for rapid detection of bluetongue virus.

AIM: The present study was designed to standardize real-time polymerase chain reaction (PCR) for detecting the bluetongue virus from blood samples of sheep collected during outbreaks of bluetongue disease in the year 2014 in Andhra Pradesh and Telangana states of India. MATERIALS AND METHODS: A 10-fold serial dilution of Plasmid PUC59 with bluetongue virus (BTV) NS3 insert was used to plot the standard curve. BHK-21 and KC cells were used for in vitro propagation of virus BTV-9 at a TCID50/ml of 105 ml and RNA was isolated by the Trizol method. Both reverse transcription-PCR and real-time PCR using TaqMan probe were carried out with RNA extracted from virus-spiked culture medium and blood to compare the sensitivity by means of finding out the limit of detection (LoD). The results were verified by inoculating the detected and undetected dilutions onto cell cultures with further cytological (cytopathic effect) and molecular confirmation (by BTV-NS1 group-specific PCR). The standardized technique was then applied to field samples (blood) for detecting BTV. RESULTS: The slope of the standard curve obtained was -3.23, and the efficiency was 103%. The LoD with RT-PCR was 8.269E×103 number of copies of plasmid, whereas it was 13 with real-time PCR for plasmid dilutions. Similarly, LoD was determined for virus-spiked culture medium, and blood with both the types of PCR and the values were 103 TCID 50/ml and 104 TCID 50/ml with RT-PCR and 10° TCID 50/ml and 102 TCID 50/ml with real-time PCR, respectively. The standardized technique was applied to blood samples collected from BTV suspected animals; 10 among 20 samples were found positive with Cq values ranging from 27 to 39. The Cq value exhibiting samples were further processed in cell cultures and were confirmed to be BT positive. Likewise, Cq undetected samples on processing in cell cultures turned out to be BTV negative. CONCLUSION: Real-time PCR was found to be a very sensitive as well as reliable method to detect BTV present in different types of samples, including blood samples collected from BTV-infected sheep, compared to RT-PCR. The LoD of BTV is likely influenced by sample type, possibly by the interference by the other components present in the sample.

Transperitoneal laparoscopic repair of retrocaval ureter: Our experience and review of literature.

CONTEXT AND AIM: Retrocaval ureter (RCU), also known as circumcaval ureter, occurs due to anomalous development of inferior vena cava (IVC) and not ureter. The surgical approach for this entity has shifted from open to laparoscopic and robotic surgery. This is a relatively new line of management with very few case reports. Herein, we describe the etiopathology, our experience with six cases of transperitoneal laparoscopic repair of RCU operated at tertiary care center in India and have reviewed different management options. METHODS: From 2013 to 2016, we operated total six cases of transperitoneal laparoscopic repair of RCU. All were male patients with average age of 29.6 years (14-50). Pain was their only complaint with normal renal function and no complications. After diagnosis with CT Urography, they underwent radionuclide scan and were operated on. Postoperative follow-up was done with ultrasonography every 3 months and repeat radionuclide scan at 6 months. The maximum follow-up was for 2.5 years. RESULTS: All cases were completed laparoscopically. Average operating time was 163.2 min. Blood loss varied from 50 to 100 cc. Ureteroureterostomy was done in all patients. None developed urinary leak or recurrent obstruction postoperatively. Maximum time for the requirement of external drainage was for 4 days (2-4 days). Average postoperative time for hospitalization was 3.8 days. Follow-up ultrasound and renal scan showed unobstructed drainage. CONCLUSIONS: Transperitoneal or retroperitoneal approach can be considered equivalent as parameters like operative time, results are comparable for these two modalities. We preferred transperitoneal approach as it provides good working space for intracorporeal suturing.

Zero-bias photocurrents in highly-disordered networks of Ge and Si nanowires.

Semiconducting nanowire (NW) devices have garnered attention in self-powered electronic and optoelectronic applications. This work explores and exhibits, for the first time for visible light, clear evidence of the zero-biased optoelectronic switching in randomly dispersed Ge and Si NW networks. The test bench, on which the NWs were dispersed for optoelectronic characterization, was fabricated using a standard CMOS fabrication process, and utilized metal contacts with dissimilar work functions-Al and Ni. The randomly dispersed NWs respond to light by exhibiting substantial photocurrents and, most remarkably, demonstrate zero-bias photo-switching. The magnitude of the photocurrent is dependent on the NW material, as well as the channel length. The photocurrent in randomly dispersed GeNWs was found to be higher by orders of magnitude compared to SiNWs. In both of these material systems, when the length of the NWs was comparable to the channel length, the currents in sparse NW networks were found to be higher than those in dense NW networks, which can be explained by considering various possible arrangements of NWs in these devices.

Retention of an endoscopic capsule.

Capsule endoscopy is a highly advanced, newer technology to look for small bowel diseases. But it has certain contraindications such as bowel narrowing, strictures that have to be ruled out on Barium studies or with computed tomography. We present a rare case of retention of endoscopic capsule even after ruling out stricture or bowel thickening on radiological imaging.

Adenocarcinoma of an Ileostomy in a Case of Hirschprung's Disease with Retroviral Disease.

The number of ileostomies created for benign diseases such as familial adenomatous polyposis and ulcerative colitis is increasing. Long-term ileostomies are prone to develop various complications over time. Ileostomy site carcinoma is a well-established complication in ulcerative colitis and familial adenomatous polyposis that have undergone total colectomy. However, no case of ileostomy site carcinoma has been described in a patient with Hirschprung's disease. We present the first case of adenocarcinoma at an ileostomy site in a patient with Hirschprung's disease with retroviral disease.

Higher-order nonlinear electromechanical effects in wurtzite GaN/AlN quantum dots.

As we demonstrated earlier, conventional mathematical models based on linear approximations may be inadequate in the analysis of properties of low-dimensional nanostructures and band structure calculations. In this work, a general three-dimensional axisymmetric coupled electromechanical model accounting for lattice mismatch, spontaneous polarization and higher-order nonlinear electrostriction effects has been applied to analyze properties of GaN/AlN quantum dots coupled with wetting layer. The generalized model that accounts for five independent electrostriction coefficients has been solved numerically via a finite-element implementation. The results, exemplified for truncated conical GaN/AlN quantum dots, demonstrate that the effect of nonlinear electrostriction in GaN/AlN nanoheterostructure quantum dots could be significant. In particular, the influence of nonlinear electromechanical effects on optoelectronic properties is highlighted by the results on band structure calculations based on a multiband effective mass theory.

Thermoelectromechanical effects in quantum dots.

Electromechanical effects are important in semiconductor nanostructures as most of the semiconductors are piezoelectric in nature. These nanostructures find applications in electronic and optoelectronic devices where they may face challenges for thermal management. Low dimensional semiconductor nanostructures, such as quantum dots (QD) and nanowires, are the nanostructures where such challenges must be particularly carefully addressed. In this contribution we report a study on thermoelectromechanical effects in QDs. For the first time a coupled model of thermoelectroelasticity has been applied to the analysis of quantum dots and the influence of thermoelectromechanical effects on bandstructures of low dimensional nanostructures has been quantified. Finite element solutions are obtained for different thermal loadings and their effects on the electromechanical properties and bandstructure of QDs are presented. Our model accounts for a practically important range of internal and external thermoelectromechanical loadings. Results are obtained for typical QD systems based on GaN/AlN and CdSe/CdS (as representatives of III-V and II-VI group semiconductors, respectively), with cylindrical and truncated conical geometries. The wetting layer effect on electromechanical quantities is also accounted for. The energy bandstructure calculations for various thermal loadings are performed. Electromechanical fields are observed to be more sensitive to thermal loadings in GaN/AlN QDs as compared to CdSe/CdS QDs. The results are discussed in the context of the effect of thermal loadings on the performance of QD-based nanosystems.