CT coronary angiography as an alternative imaging method to ascertain cardiac output and its correlation with echocardiography

AIM

To assess the feasibility and accuracy of cardiac output (CO) obtained using a test bolus in patients scanned with single-source prospective-gated cardiac computed tomography (CT), and comparing it with CO obtained from unenhanced two-dimensional (2D) echocardiography using biplane Simpson's method.

MATERIALS AND METHODS

In the present study, 100 patients with a mean age of 55 ± 12 years who underwent coronary CT angiography with prospective electrocardiogram (ECG)-gated CT in which the scan delay was evaluated using a test bolus. The time-attenuation curves obtained from the test bolus were used to calculate the CO of the patients. The CO obtained was then compared with that obtained after follow-up 2D echocardiography using biplane modified Simpson method.

RESULTS

Linear regression was calculated between the CO and contrast enhancement: CO = -0.16(HUmax) + 7.65. The study showed good correlation between the two methods with r=0.77, p<0.001. On Bland-Altman analysis, no significant difference was noted between the two methods.

CONCLUSION

This less researched method for CO estimation appears feasible; however, the clinical usefulness of this parameter is uncertain in absence of further clinical and reference standard validation.

Turbulence suppression by cardiac-cycle-inspired driving of pipe flow

Flows through pipes and channels are, in practice, almost always turbulent, and the multiscale eddying motion is responsible for a major part of the encountered friction losses and pumping costs1. Conversely, for pulsatile flows, in particular for aortic blood flow, turbulence levels remain low despite relatively large peak velocities. For aortic blood flow, high turbulence levels are intolerable as they would damage the shear-sensitive endothelial cell layer2-5. Here we show that turbulence in ordinary pipe flow is diminished if the flow is driven in a pulsatile mode that incorporates all the key features of the cardiac waveform. At Reynolds numbers comparable to those of aortic blood flow, turbulence is largely inhibited, whereas at much higher speeds, the turbulent drag is reduced by more than 25%. This specific operation mode is more efficient when compared with steady driving, which is the present situation for virtually all fluid transport processes ranging from heating circuits to water, gas and oil pipelines.

Identification of miRNAs associated with dendritic cell dysfunction during acute and chronic hepatitis B virus infection

The uptake or expression of hepatitis B virus (HBV) proteins by dendritic cells (DCs) is considered important for disease outcome. Differential expression of microRNA (miRNA) may have a role in viral persistence and hepatocellular injury. The miRNA expression was investigated by microarray in DCs from different stages of HBV infection and liver disease namely, immune active (IA; n = 20); low replicative (LR; n = 20); HBeAg negative (n = 20); acute viral hepatitis (AVH, n = 20) and healthy controls (n = 20). miRNA levels were analyzed by unsupervised hierarchical clustering and principal component analyses and validated by quantitative polymerase Chain Reaction (qPCR). The miRNA-messenger RNA (mRNA)regulatory networks identified 19 miRNAs and 12 target gene interactions in major histocompatibility complex and other immune pathways. miR-2278, miR-615-3p, and miR-3681-3p were downregulated in the IA group compared to healthy control, miR-152-3p and miR-3613-3p in the LR group compared to IA group and miR-152-3p and miR-503-3p in HBe negative compared to LR group. However, miR-7-1-1-3p, miR-192-5p, miR-195-5p, and miR-32-5p in LR, miR-342-3p, and miR-940 in HBe negative, and miR-34a-5p, miR-130b-3p, miR-221-3p, miR-320a, miR-324-5p, and miR-484 in AVH were upregulated. Further, qPCR confirmed changes in miRNA levels and their target genes associated with antigen processing and presentation. Thus, a deregulated network of miRNAs-mRNAs in DCs seems responsible for an impaired immune response during HBV pathogenesis.

Challenges in Sensors Technology for Industry 4.0 for Futuristic Metrological Applications

The current advances and innovations in sensor technologies attributed to Industry 4.0 serve as the backbone for the inclusive growth of industry and ramping up the economy of any country. Industry 4.0 was basically conceptualized by introducing the Internet of Things (IoT) and Information and Communication technologies (ICT) that serve as an interface between digital and physical world through the fusion of smart sensors. The role of smart sensors and IoT-enabled industrial infrastructure is pivotal for adapting to the advanced technologies based on fusion of smart sensors. Digital meteorological traceability and uses of intelligent sensors, instrumentation and machinery in Industry 4.0, Smart Cities, Digital India and AtmaNirbhar Bharat missions of the government of India, are not only highly important but also in huge demand, which is going to increase manifolds in the years to come. The present paper is an attempt to provide a terse review and perspectives related to the advanced technological developments in this field and the challenges therein.

BA3338, a surface layer homology domain possessing protein augments immune response and protection efficacy of protective antigen against Bacillus anthracis in mouse model

AIM

Category A classified Bacillus anthracis is highly fatal pathogen that causes anthrax and creates challenges for global security and public health. In this study, development of a safe and ideal next-generation subunit anthrax vaccine has been evaluated in mouse model.

METHOD AND RESULTS

Protective antigen (PA) and BA3338, a surface layer homology (SLH) domain possessing protein were cloned, expressed in heterologous system and purified by IMAC. Recombinant PA and BA3338 with alum were administered in mouse alone or in combination. The humoral and cell-mediated immune response was measured by ELISA and vaccinated animals were challenged with B. anthracis spores via intraperitoneal route. The circulating IgG antibody titre of anti-PA and anti-BA3338 was found significantly high in the first and second booster sera. A significant enhanced level of IL-4, IFN-γ and IL-12 was observed in antigens stimulated supernatant of splenocytes of PA + BA3338 vaccinated animals. A combination of PA and BA3338 provided 80% protection against 20 LD₅₀ lethal dose of B. anthracis spores.

CONCLUSION

Both antigens induced admirable humoral and cellular immune response as well as protective efficacy against B. anthracis spores.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study has been evaluated for the first time using BA3338 as a vaccine candidate alone or in combination with well-known anthrax vaccine candidate PA. The findings of this study demonstrated that BA3338 could be a co-vaccine candidate for development of dual subunit vaccine against anthrax.

Characterization of liver specific promoters in a foamy viral vector pMD09

Foamy viruses (FVs) or spumaviruses are retroviruses that are explored as vectors for gene therapy. The good feature of foamy viruses is its broad tropism; however, their infections result in non-targeted gene expression. Here, we attempted to design the liver targeted viral gene delivery by employing liver specific gene promoters like albumin (ALB), transthyretin (TTR) and hepatitis B virus (HBV) promoters. We compared the relative gene expression of liver specific promoters versus the U3 promoter in liver cell line (HepG2) and non-liver cell lines: human fibrosarcoma cell line (HT1080), baby hamster kidney cell line (BHK), human embryonic kidney cell line (HEK 293T) and cervical cancer cell line (HeLa). We have found that the promoter exchange didn't affect viral assembly. The ability to drive gene expression was best with TTR promoter which was followed by HBV and ALB promoter. The use of TTR, HBV and ALB promoters are helpful in achieving liver specific gene expression. Keywords: foamy virus; gene therapy; liver; albumin; transthyretin promoter; HBV promoter.

Global microRNA expression profiling in the liver biopsies of hepatitis B virus-infected patients suggests specific microRNA signatures for viral persistence and hepatocellular injury

Hepatitis B virus (HBV) can manipulate the microRNA (miRNA) regulatory networks in infected cells to create a permissive environment for viral replication, cellular injury, disease onset, and its progression. The aim of the present study was to understand the miRNA networks and their target genes in the liver of hepatitis B patients involved in HBV replication, liver injury, and liver fibrosis. We investigated differentially expressed miRNAs by microarray in liver biopsy samples from different stages of HBV infection and liver disease (immune-tolerant [n = 8], acute viral hepatitis [n = 8], no fibrosis [n = 16], early [F1+F2, n = 19] or late [F3+F4, n = 14] fibrosis, and healthy controls [n = 7]). miRNA expression levels were analyzed by unsupervised principal component analysis and hierarchical clustering. Analysis of miRNA-mRNA regulatory networks identified 17 miRNAs and 18 target gene interactions with four distinct nodes, each representing a stage-specific gene regulation during disease progression. The immune-tolerant group showed elevated miR-199a-5p, miR-221-3p, and Let-7a-3p levels, which could target genes involved in innate immune response and viral replication. In the acute viral hepatitis group, miR-125b-5p and miR-3613-3p were up, whereas miR-940 was down, which might affect cell proliferation through the signal transducer and activator of transcription 3 pathway. In early fibrosis, miR-34b-3p, miR-1224-3p, and miR-1227-3p were up, while miR-499a-5p was down, which together possibly mediate chronic inflammation. In advanced fibrosis, miR-1, miR-10b-5p, miR-96-5p, miR-133b, and miR-671-5p were up, while miR-20b-5p and miR-455-3p were down, possibly allowing chronic disease progression. Interestingly, only 8 of 17 liver-specific miRNAs exhibited a similar expression pattern in patient sera.

CONCLUSION

miRNA signatures identified in this study corroborate previous findings and provide fresh insight into the understanding of HBV-associated liver diseases which may be helpful in developing early-stage disease diagnostics and targeted therapeutics. (Hepatology 2018;67:1695-1709).

Targeted delivery of microRNA-199a-3p using self-assembled dipeptide nanoparticles efficiently reduces hepatocellular carcinoma in mice

Hepatocellular carcinoma (HCC) is an aggressive tumor with limited systemic and locoregional modalities of treatment. Although microRNA (miRNA) based therapies have significant potential, their targeted delivery remains a major challenge. miR-199a-3p functions as an important tumor suppressor in HCC, which regulates various cellular processes. Recently, peptide-based nanoparticles (NPs) have been developed to deliver oligonucleotides including miRNA. Here, we describe the synthesis and characterization of arginine α,β-dehydrophenylalanine (RΔF) nanoparticles for the selective delivery of miR-199a-3p to restore dysregulated gene expression in HCC. Targeted delivery was achieved by conjugating lactobionic acid (LA) with RΔF NPs (RΔF-LA NPs), a ligand for the asialoglycoprotein receptor known to be overexpressed in HCC cell lines. RΔF-LA NPs condensed miR-199a-3p had an average size of ∼60nm and a zeta potential of ∼+2.54 mV. RΔF-LA/miR NPs were found to be stable in serum as well as against RNase attack. RΔF-LA/miR NPs showed an enhanced cellular uptake and an efficient delivery of miR-199a-3p leading to a significant increase in miR-199a-3p levels (over 500 fold). The increased miR-199a-3p levels remarkably suppressed cell proliferation and migration as well as induced cellular apoptosis and downregulation of the specific target gene (mTOR) in vitro. RΔF-LA/miR NPs showed high tumor/ low organ ratios after intravenous injection into HCC tumor bearing nude mice. RΔF-LA/miR NPs treated mice demonstrated>50% decline in tumor growth, which also corresponded well with suppression of mTOR protein expression, tumor cell proliferation and increased survival rate (P < 0.05).

CONCLUSION

RΔF-LA/miR NPs showed significantly enhanced delivery of the miRNA which underscores their potential for further development as a therapeutic approach for HCC. (Hepatology 2018;67:1392-1407).

An RNAi-based high-throughput screening assay to identify small molecule inhibitors of hepatitis B virus replication

Persistent or chronic infection with the hepatitis B virus (HBV) represents one of the most common viral diseases in humans. The hepatitis B virus deploys the hepatitis B virus X protein (HBx) as a suppressor of host defenses consisting of RNAi-based silencing of viral genes. Because of its critical role in countering host defenses, HBx represents an attractive target for antiviral drugs. Here, we developed and optimized a loss-of-function screening procedure, which identified a potential pharmacophore that abrogated HBx RNAi suppression activity. In a survey of 14,400 compounds in the Maybridge Screening Collection, we prioritized candidate compounds via high-throughput screening based on reversal of green fluorescent protein (GFP)-reported, RNAi-mediated silencing in a HepG2/GFP-shRNA RNAi sensor line. The screening yielded a pharmacologically active compound, N-(2,4-difluorophenyl)-N'-[3-(1H-imidazol-1-yl) propyl] thiourea (IR415), which blocked HBx-mediated RNAi suppression indicated by the GFP reporter assay. We also found that IR415 reversed the inhibitory effect of HBx protein on activity of the Dicer endoribonuclease. We further confirmed the results of the primary screen in IR415-treated, HBV-infected HepG2 cells, which exhibited a marked depletion of HBV core protein synthesis and down-regulation of pre-genomic HBV RNA. Using a molecular interaction analysis system, we confirmed that IR415 selectively targets HBx in a concentration-dependent manner. The screening assay presented here allows rapid and improved detection of small-molecule inhibitors of HBx and related viral proteins. The assay may therefore potentiate the development of next-generation RNAi pathway-based therapeutics and promises to accelerate our search for novel and effective drugs in antiviral research.

Analysis of hepatitis B virus genotype changes in patients with chronic hepatitis B infection on tenofovir therapy

Antiviral therapy for chronic hepatitis B (CHB) is often required for prolonged periods. We investigated the instance of one HBV genotype switching to another during tenofovir therapy. Of the 67 patients, genotype A was present in 6 (8.9%), D in 43 (65.6%), C in 1 (1.5%), and mixed in 17 (23.8%) patients. Genotype changes were detected in 51 (76.1%) patients on therapy during a follow-up of 192 (range 52-312) weeks. Inter-genotype changes were seen in 17 (33.3%) and intra-genotype in 28 (55%) and both inter- and intra-genotype in 6 of 51 (11.7%) patients. The distribution of genotypes in patients achieving complete virological response was genotype D, 32/43 (74.4%); genotype A, 6/6 (100%); and mixed genotypes, 13/17 (76.47%). The cumulative time of genotype switch among genotype A was 12 months (range 6-18), in genotype D, 12 months (range 6-48), and mixed genotype, 18 months (range 6-24). The type of inter-genotype switch most frequently detected among genotype A1 was from A1 to D1 5/6 (83.3%), followed by mixed to genotype D3 7/13 (54%) and among intra-genotype changes, from D1 to D3 in 14/20 (70%). Pretreatment HBV genotype was the only factor predicting inter-genotype switches with genotype A or mixed genotypes more likely to undergo inter-genotype switches as compared to genotype D patients (OR 66.6 [13.6-327.0, P < 0.001]). Compared to genotype D, genotype A, and mixed genotypes are more inclined to switch while on tenofovir therapy. Genotypes tend to switch and select to a particular type possibly due to constant antiviral drug pressure. J. Med. Virol. 88:1364-1375, 2016. © 2016 Wiley Periodicals, Inc.

Key elements of the RNAi pathway are regulated by hepatitis B virus replication and HBx acts as a viral suppressor of RNA silencing

The host-mediated RNAi pathways restrict replication of viruses in plant, invertebrate and vertebrate systems. However, comparatively little is known about the interplay between RNAi and various viral infections in mammalian hosts. We show in the present study that the siRNA-mediated silencing of Drosha, Dicer and Ago2 [argonaute RISC (RNA-induced silencing complex) catalytic component 2] transcripts in Huh7 cells resulted in elevated levels of HBV (hepatitis B virus)-specific RNAs and, conversely, we observed a decrease in mRNA and protein levels of same RNAi components in HepG2 cells infected with HBV. Similar reductions were also detectable in CHB (chronic hepatitis B) patients. Analysis of CHB liver biopsy samples, with high serum HBV DNA load (>log108 IU/ml), revealed a reduced mRNA and protein levels of Drosha, Dicer and Ago2. The low expression levels of key RNAi pathway components in CHB patient samples as well as hepatic cells established a link between HBV replication and RNAi components. The HBV proteins were also examined for RSS (RNA-silencing suppressor) properties. Using GFP-based reversion of silencing assays, in the present study we found that HBx is an RSS protein. Through a series of deletions and substitution mutants, we found that the full-length HBx protein is required for optimum RSS activity. The in vitro dicing assays revealed that the HBx protein inhibited the human Dicer-mediated processing of dsRNAs into siRNAs. Together, our results suggest that the HBx protein might function as RSS to manipulate host RNAi defence, in particular by abrogating the function of Dicer. The present study may have implications in the development of newer strategies to combat HBV infection.

School eye survey in rural population in UP, India

OBJECTIVE

To find out the prevalence of refractive errors and pattern of ocular morbidity amongst the school children of a rural village.

MATERIALS AND METHODS

A cross sectional study was carried out in children of age group 3 - 12 years in a rural village of Hathras, Uttar Pradesh, India. All the children were examined including visual acuity measurement using Snellen's E chart, retinoscopy and refraction under cycloplegia. Examination of the anterior segment, media, and fundii was also done. Myopia was defined as spherical/cylindrical equivalent refractive error of at least -0.50 D and hypermetropia as +0.50 D or more (Dandona et al 2002).

RESULTS

In the survey 220 eyes of 110 children were examined, majority of them were in 5-10 year age group. The prevalence of uncorrected visual acuity of 6/6 was 85.40%. Refractive error was the cause in 6.81% of eyes with vision impairment, out of which myopia and hypermetropia were present in 26.67% of eyes. Blepharo-conjunctivitis was present in 15.45% of children and Bitot's spots were present in 0.90% of them. Colour blindness was found in one child.

CONCLUSION

The prevalence of refractive error in rural school is 6.81 %. Blepharitis is the commonest cause of ocular morbidity.

Hierarchical Exploration of Volumes Using Multilevel Segmentation of the Intensity-Gradient Histograms

Visual exploration of volumetric datasets to discover the embedded features and spatial structures is a challenging and tedious task. In this paper we present a semi-automatic approach to this problem that works by visually segmenting the intensity-gradient 2D histogram of a volumetric dataset into an exploration hierarchy. Our approach mimics user exploration behavior by analyzing the histogram with the normalized-cut multilevel segmentation technique. Unlike previous work in this area, our technique segments the histogram into a reasonable set of intuitive components that are mutually exclusive and collectively exhaustive. We use information-theoretic measures of the volumetric data segments to guide the exploration. This provides a data-driven coarse-to-fine hierarchy for a user to interactively navigate the volume in a meaningful manner.

Phosphorous magnetic resonance spectroscopy-based skeletal muscle bioenergetic studies in subclinical hypothyroidism

BACKGROUND

Subclinical hypothyroidism (sHT) is considered to be a milder form of thyroid dysfunction. Few earlier studies have reported neuromuscular symptoms as well as impaired muscle metabolism in sHT patients.

AIM/OBJECTIVE

In this study we report our findings on muscle bioenergetics in sHT patients using phosphorous magnetic resonance spectroscopy (31P MRS) and look upon the possibility to use 31P MRS technique as a clinical marker for monitoring muscle function in subclinical thyroid dysfunction.

SUBJECTS AND METHODS

Seventeen normal subjects, 15 patients with sHT, and 9 patients with hypothyroidism performed plantar flexion exercise while lying supine in 1.5 T magnetic resonance scanner using custom built exercise device. MR Spectroscopy measurements of inorganic phosphate (Pi), phosphocreatine (PCr), and ATP of the calf muscle were taken during rest, at the end of exercise and in the recovery phase. PCr recovery rate constant (kPCr) and oxidative capacity were calculated by monoexponential fit of PCr vs time (t) at the beginning of recovery.

RESULTS

We observed that changes in some of the phosphometabolites (increased phosphodiester levels and Pi concentration) in sHT patients which were similar to those detected in patients with hypothyroidism. However, our results do not demonstrate impaired muscle oxidative metabolism in sHT patients based upon PCr dynamics as observed in hypothyroid patients.

CONCLUSIONS

31P MRS-based PCr recovery rate could be used as a marker for monitoring muscle oxidative metabolism in sub clinical thyroid dysfunction.

Social snapshot: a system for temporally coupled social photography

Social Snapshot actively acquires and reconstructs temporally dynamic data. The system enables spatiotemporal 3D photography using commodity devices, assisted by their auxiliary sensors and network functionality. It engages users, making them active rather than passive participants in data acquisition.

pH-Dependent urea-induced unfolding of stem bromelain: unusual stability against urea at neutral pH

Equilibrium unfolding of stem bromelain (SB) with urea as a denaturant has been monitored as a function of pH using circular dichroism and fluorescence emission spectroscopy. Urea-induced denaturation studies at pH 4.5 showed that SB unfolds through a two-state mechanism and yields DeltaG (free energy difference between the fully folded and unfolded forms) of approximately 5.0 kcal/mol and C(m) (midpoint of the unfolding transition) of approximately 6.5 M at 25 degrees C. Very high concentration of urea (9.5 M) provides unusual stability to the protein with no more structural loss and transition to a completely unfolded state.

Development and validation of CAPS and AFLP markers for white rust resistance gene in Brassica juncea

White rust, caused by Albugo candida, is a very serious disease in crucifers. In Indian mustard (Brassica juncea), it can cause a yield loss to the extent of 89.9%. The locus Ac2(t) controlling resistance to white rust in BEC-144, an exotic accession of mustard, was mapped using RAPD markers. In the present study, we developed: (1) a more tightly linked marker for the white rust resistance gene, using AFLP in conjunction with bulk segregant analysis, and (2) a PCR-based cleaved amplified polymorphic sequence (CAPS) marker for the closely linked RAPD marker, OPB06(1000). The data obtained on 94 RILs revealed that the CAPS marker for OPB06(1000) and the AFLP marker E-ACC/M-CAA(350) flank the Ac2(t) gene at 3.8 cM and 6.7 cM, respectively. Validation of the CAPS marker in two different F(2) populations of crosses Varuna x BEC-144 and Varuna x BEC-286 was also undertaken, which established its utility in marker-assisted selection (MAS) for white rust resistance. The use of both flanking markers in MAS would allow only 0.25% misclassification and thus provide greater efficiency to selection.

Symptomatic small non-obstructing lower ureteric calculi: comparison of ureteroscopy and extra corporeal shock wave lithotripsy

OBJECTIVE

To compare the success, efficacy and complications of ureteroscopy (URS) and extra corporeal shock wave lithotripsy (ESWL) for the treatment of symptomatic small non obstructing lower ureteric calculi.

SUBJECTS AND METHODS

This prospective non-randomised study was conducted simultaneously at two urological referral centres, included 280 patients with symptomatic small (4-10 mm) lower ureteric calculi (situated below the sacroiliac joint), with good renal function on intravenous urography. Patients were offered both the treatment options. One hundred and sixty patients chose ureteroscopy, whereas 120 patients were treated by ESWL. Standard techniques of ureteroscopy and ESWL were employed. Patients were followed-up to assess the success rates and complications of the two procedures.

RESULTS

Ureteroscopy achieved complete stone clearance in one session in 95% of patients. In six patients ureteroscopy had failed initially and was later accomplished in second session improving the success rate to 98.7%. Two patients had a proximal migration of calculus that needed ESWL. Of the 120 patients treated by ESWL, 90% achieved stone free status at three months. Ureteroscopy was needed for twelve patients (10%) where ESWL failed to achieve stone clearance. There were no significant ESWL related complications. ESWL was administered on outpatient basis, while patients needed hospitalisation and anaesthesia for ureteroscopy.

CONCLUSION

ESWL can be the primary mode of treatment for symptomatic small non-obstructing lower ureteric calculi as it is minimally invasive and safe. Ureteroscopy can be offered to patients who demand immediate relief or when ESWL fails.

Resting membrane potential as a marker of apoptosis: studies on Xenopus oocytes microinjected with cytochrome c

Observation of the electrical potential difference across the cell membrane is described as a new method for monitoring apoptosis of a single cell. The resting membrane potential (DeltaPsi) of Xenopus oocytes has been recorded in real time following microinjection of cytochrome c. Soon after microinjection, DeltaPsi becomes less negative and attains a new constant value with a half time, t(m), of about 35 (+ /- 5) min at all cytochrome c concentrations greater than 1 microM. The cytosol extract of cytochrome c-injected oocytes shows DEVD proteolytic activity characteristic of aspartate specific proteases, implicating an apoptotic death pathway. In response to the delivery of cytochrome c into the cytosol, caspases are activated within 7 min while the changes in DeltaPsi begin to occur after about 30 min. The method described here will be potentially useful to assess the effectiveness of cell death regulators and modulators of synthetic and biological origin, and the results presented shed light on the currently debated issue of the importance of the redox state of cytochrome c in the initiation of apoptosis.

Cytoplasmic residues influence the voltage-dependence of the gating of human K+ channels

Shaker type potassium channels are strongly voltage dependent and potassium selective. Kv1.4 channels from a variety of sources exhibit a much shallower voltage-dependence of activation than other members of the family. We have made a chimeric construct consisting of the N-terminal chain of hKv1.1 spliced onto the transmembrane portion of hKv1.4 (IN/4). When expressed in Xenopus oocytes, the chimeric channel exhibits a voltage dependence that is similar to hKv1.1 although the voltage sensing and transduction machinery presumably reside in the transmembrane portion of the channel. Loss of the N-terminal ball and chain from hKv1.4 is not responsible for this as a truncation construct, starting close to the splice junction, has the same voltage-dependence as full length hKv1.4. We suggest that residues from the N-terminal chain of hKv1.1 interact with the machinery that transduces movement of the voltage sensor into channel opening. If so, this chimeric construct could provide a handle to the identification of elements of this transduction machinery.

Exploring the architecture of potassium channels using chimaeras to reveal signal transduction

The chimeric channel, 4N/1, generated from two outwardly rectifying K+ channels by linking the N-terminal cytoplasmic domain of hKv1.4 with the transmembrane body of hKv1.1, functions as an inward rectifier. The operating range of the channel is shifted to hyperpolarizing potentials and it is inactivated at resting membrane potentials. Co-expression of a truncated form of hKv1.1 with the N-terminal domain of hKv1.4 results in the same physiology as the chimaera implying specific interactions between the two segments.

Transplanting the N-terminus from Kv1.4 to Kv1.1 generates an inwardly rectifying K+ channel

A chimeric channel, 4N/1, was generated from two outwardly rectifying K+ channels by linking the N-terminal cytoplasmic domain of hKv1.4 (N terminus ball and chain of hKv1.4) with the transmembrane body of hKv1.1 (delta78N1 construct of hKv1.1). The recombinant channel has properties similar to the six transmembrane inward rectifiers and opens on hyperpolarization with a threshold of activation at -90 mV. Outward currents are seen on depolarization provided the channel is first exposed to a hyperpolarizing pulse of -100 mV or more. Hyperpolarization at and beyond -130 mV provides evidence of channel deactivation. Delta78N1 does not show inward currents on hyperpolarization but does open on depolarizing from -80 mV with characteristics similar to native hKv1.1. The outward currents seen in both delta78N1 and 4N/1 inactivate slowly at rates consistent with C-type inactivation. The inward rectification of the 4N/1 chimera is consistent with the inactivation gating mechanism. This implies that the addition of the N-terminus from hKv1.4 to hKv1.1 shifts channel activation to hyperpolarizing potentials. These results suggest a mechanism involving the N-terminal cytoplasmic domain for conversion of outward rectifiers to inward rectifiers.

Electroacupuncture, morphine and clonidine: a comparative study of analgesic effects

This is a comparative study of the analgesic effects of the modified traditional method of analgesia, electroacupuncture (EA), a standard analgesic drug, morphine, a potential analgesic drug, clonidine and the combination of EA + morphine and EA + clonidine. In each case, the index of analgesia (IA) was determined by recording the tail flick latency (TFL) in 60 rats divided into 6 groups of 10 rats each. Group I rats served as control group while Group II-VI were subjected to EA for 20 min (at Zusanli and Kunlun points), morphine (5 mg/kg bw i.p.), clonidine (150 micrograms/kg bw i.p.), EA + morphine and EA + clonidine respectively. TFLs were recorded after the procedure and at 10 min intervals for 150 min or til the TFL returned to¿ the baseline. The IA, analyzed using the Kruskal-Wallis test and its significance determined by multiple comparison test (at 5% level), was found to be significantly different, at various time intervals, in the 6 groups studied.

Comparison of developmental stages of inflorescence for high frequency plant regeneration in Triticum aestivum L. and T. durum Desf

Whole immature inflorescences at 4 different developmental stages (0.5, 1.0, 1.5, 2.0 cm in size) of different genotypes of Triticum aestivum and T. durum were cultured to see the morphogenetic responses on Murashige and Skoog's (MS) medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) (2.5 mg/l). Very young inflorescences 0.5 and 1.0cm long formed embryogenic callus from their entire surface while 1.5 and 2.0 cm long inflorescences formed embryogenic callus from the basal spikelets and rachis only. This embryogenic callus was maintained by regular subcultures on MS medium with 2,4-D (2.5 mg/l) for more than a year. Plantlets were regenerated by transferring the embryogenic callus on hormone-free MS medium. Inflorescences (0.5 and 1.0 cm long) responded best in forming callus as well as plantlets at a very high frequency. Variation in response was observed amongst the genotypes but the qualitative response of formation of embryogenic callus and later regeneration of plantlets was observed from all the genotypes. Immature young inflorescence explants could provide a suitable material for particle gun mediated genetic transformation in wheat.

Effect of hypoxia and acidosis on the cytotoxicity of mitoxantrone, bisantrene and amsacrine and their platinum complexes at normal and hyperthermic temperatures

In an effort to synthesize drugs which would become much more cytotoxic at clinically achievable hyperthermic temperatures, complexes of the tetrachloro-platinum(II) dianion were made with two anthracene dye derivatives, MITOX and BISANT, and the acridine dye derivative m-AMSA. As compared with the parent drug, PtCl4(MITOX)2 was less cytotoxic at 37 degrees C and more cytotoxic at 42 degrees C and 43 degrees C especially at pH 6.45. In contrast, the PtCl4(BISANT)2 was more cytotoxic than BISANT under all conditions. M-AMSA was again shown to be less cytotoxic at elevated temperatures but PtCl4(m-AMSA)2 was more cytotoxic especially at 43 degrees C and pH 6.45. Platinum levels in cells treated for 1 hr with 25 microM at 37 degrees C, 42 degrees C and at pH 7.40 versus pH 6.45 demonstrated no significant differences depending on temperature or pH except for PtCl4(MITOX)2 where approximately 4 times higher intracellular platinum levels were present at pH 6.45 versus pH 7.40, although this finding did not correlate with cytotoxicity. These results suggest that PtCl4(MITOX)2 and PtCl4(m-AMSA)2 may be highly interactive drugs with local hyperthermia.

Multiple modality treatment of carcinoma cells with Pt(Rh-123)2 plus x-ray plus light

A complex of platinum tetrachloride with two molecules of rhodamine-123 (Rh-123), Pt(Rh-123)2, has been reported to act as hypoxic cell radiosensitizer of carcinoma cells in vitro and in vivo. In the present paper we report that Pt(Rh-123)2 photosensitizes human mammary carcinoma (MCF-7) cells and cis-platinum resistant human mammary carcinoma (MCF-7/CP) cells to 400-800 nm light in vitro. The efficiency of photosensitization by Pt(Rh-123)2 was 10 times greater than for Rh-123. Combination therapy using Pt(Rh-123)2 plus x-ray plus light was also much more effective compared to the combination therapy using Rh-123 plus x-ray plus light. After 15 microM of Rh-123 plus x-ray (0-8 Gy) plus light (5 J/cm2) treatment, cell survival curve was parallel to the x-ray cell survival curve with an initial decrease in the surviving fraction corresponding to the drug plus light mediated killing. Cell killing caused by Rh-123 (15 microM) plus x-ray (0-8 Gy) plus light (5 J/cm2) was additive as determined by the product of the surviving fraction after Rh-123 plus light and x-ray. In contrast, for 15 microM of Pt(Rh-123)2 plus x-ray (8 Gy) plus light (5 J/cm2) treatment, whereas additive killing predicts a survival fraction of approximately 0.024, in reality, the combination therapy caused the survival fraction to decrease to 0.0012, implying that the cell killing was enhanced by a factor of 20. Using Pt(Rh-123)2 plus x-ray plus light, supra-additive cell killing was also observed under hypoxic conditions, although compared to normally oxygenated conditions the degree of cytotoxicity was significantly reduced.(ABSTRACT TRUNCATED AT 250 WORDS)

Interaction of D,L- and D-tetraplatin with hyperthermia in vitro and in vivo

The cytotoxicities of D,L-tetraplatin and D-tetraplatin were evaluated at 37 degrees C, 42 degrees C and 43 degrees C at normal pH, at pH 6.45 and under normally oxygenated and hypoxic conditions in EMT-6 cells in vitro. The D-isomer was also tested in FSaIIC cells in vitro. Under these various conditions the pure D-isomer was very similar in cytotoxicity with the racemic mixture. Like cisplatin, both D,L- and D-tetraplatin were selectively cytotoxic toward normally oxygenated cells under acidic pH (6.45) conditions at 37 degrees C. In both cell lines the cytotoxicity of D,L- and D-tetraplatin was markedly increased at hyperthermic temperatures. Under the same conditions platinum levels in EMT-6 cells exposed to D,L- or D-tetraplatin were higher than in cells exposed to cisplatin, and unlike cisplatin there was an increase in intracellular platinum levels when the cells were exposed to D,L- or D-tetraplatin at 42 degrees C compared with 37 degrees C. The tumour growth delay of the FSaIIC fibrosarcoma was the same for D,L- and D-tetraplatin. A dose of 10 mg/kg intraperitoneally of tetraplatin produced a tumour growth delay of about 4.3 days which was increased to about 6 days with the addition of local hyperthermia (43 degrees C, 30 min) to the drug treatment. The tumour cell survival assay also showed no difference between D,L- and D-tetraplatin and a log-linear increase in tumour cell killing with increasing drug dose which was increased 1.5-3-fold with local hyperthermia. D,L- and D-tetraplatin were relatively much more cytotoxic toward bone marrow colony forming units of granulocyte-macrophage progenitors (CFU-GM) than was cisplatin and this cytotoxicity was increased about 5-10-fold under hyperthermic conditions. There was an increase in DNA crosslink formation in tumours when hyperthermia accompanied tetraplatin treatment. Overall, D,L- and D-tetraplatin produced very similar responses under hyperthermic conditions in both tumour and normal tissues, and may be a useful agent in combination with local hyperthermia.

Effect of hypoxia and acidosis on the cytotoxicity of six metal(ligand)4(rhodamine-123)2 complexes at normal and hyperthermic temperatures

Several analogues of PtCl4(Rh-123)2 in which the metal may be Pt or Pd and the coordinated ligand may be -Cl, -CN or -NO2 were prepared and tested in cell culture with EMT-6 cells at normal (37 degrees C) and hyperthermic (42 degrees C and 43 degrees C) temperatures and various environmental conditions (normally oxygenated vs. hypoxic and pH 7.40 vs. pH 6.45). Pd is a much more reactive metal than Pt, while -CN and -NO2 are more tightly bound ligands than is -Cl. The goal of these studies was to define the complex with the least cytotoxicity at 37 degrees C and the greatest enhancement in cytotoxicity under hyperthermic conditions. The Pt complexes Pt(CN)4(Rh-123)2 and Pt(NO2)4(Rh-123)2 were much less cytotoxic than PtCl4(Rh-123)2 under both normothermic and hyperthermic conditions. The Pd complexes were, in general, more cytotoxic than the corresponding Pt complexes. The level of metal (Pt or Pd) in the cells did not appear to be a major factor in the level of cytotoxicity obtained. Complexes which were not cytotoxic at 37 degrees C regardless of oxygenation level or pH did not become cytotoxic at hyperthermic temperatures. In conclusion, the optimal members of this series were the complexes with chloro ligands, indicating that aquation is probably a necessary step in the cytotoxic mechanism and cytotoxicity at 37 degrees C was necessary to obtain cytotoxicity at higher temperatures.

A report on a rare case of Kearns Sayre-like syndrome

Purpose: To report the presentation of a rare case of Kearns-Sayre-like syndrome (KSS) Case: A 14-year-old boy presented with progressive drooping of both upper eyelids for 10 years. Past history of right sided hemi-plegia and left facial nerve palsy was present. Examination (OU) showed total external ophthalmoplegia, ptosis and pigmentary retinopathy. The patient also had a short stature (height 121.9 cm) for his age. Keywords: Kearns Sayre syndrome; total external ophthalmoplegia; ptosis DOI: 10.3126/nepjoph.v2i2.3725 Nep J Oph 2010;2(2) 160-163