Cross-sectional study on rotavirus A (RVA) infection and assessment of risk factors in pre- and post-weaning piglets in India.

Rotavirus A (RVA) infections are known to retard the piglets' growth and minimize the profit to the pig farming community. Between August 2014 and July 2017, in a cross-sectional study, we surveyed 13 organized pig farms located in the eight states of India representing northern, north-eastern and southern regions, to identify the risk factors associated with RVA infection in pre- and post-weaning piglets. Faecal samples (n = 411) comprising of non-diarrhoeic (n = 320) and diarrhoeic (n = 91) were collected and screened for RVA infection using VP6 gene-based RT-PCR. RVA positivity of 52.5% (168/320) in non-diarrhoeic and 59.3% (54/91) in diarrhoeic piglets was noticed. Further, 53.3% (120/225) and 54.8% (102/186) of the samples from pre- and post-weaned samples were positive for RVA, respectively. To note, no statistically significant association was noticed between RVA infection, health and weaning status. Additionally, a questionnaire-based survey was conducted to identify the risk factors for RVA infections in piglets. The analysis revealed that good ventilation (OR 0.2, 95% CI 0.15-0.39), use of deep well water (OR 0.2, 95% CI 0.13-0.43) and feeding of commercial feed (OR 0.3, 95% CI 0.18-0.41) were associated with reduced risk of RVA infection compared with poor ventilation, use of shallow well water and feeding of own milled feed, respectively. Contrarily, mixed farms (OR 2.1, 95% CI 1.26-3.37), use of heater or cooler (OR 5.9, 95% CI 3.74-9.30), sheds in different elevation (OR 2.5, 95% CI 1.20-5.01) and weekly and occasional use of disinfectant for surface cleaning (OR 1.8, 95% CI 1.12-2.96) were associated with higher RVA infection. Mitigating the risk factors might help in better health management of piglets and increase the economic return to pig farming community in the country.

Determining equilibrium osmolarity in poly(ethylene glycol)/chondrotin sulfate gels mimicking articular cartilage.

We present an experimentally guided, multi-phase, multi-species polyelectrolyte gel model to make qualitative predictions on the equilibrium electro-chemical properties of articular cartilage. The mixture theory consists of two different types of polymers: poly(ethylene gylcol) (PEG), chondrotin sulfate (ChS), water (acting as solvent) and several different ions: H(+), Na(+), Cl(-). The polymer chains have covalent cross-links whose effect on the swelling kinetics is modeled via Doi rubber elasticity theory. Numerical studies on equilibrium polymer volume fraction and net osmolarity (difference in the solute concentration across the gel) show a complex interplay between ionic bath concentrations, pH, cross-link fraction and the average charge per monomer. Generally speaking, swelling is aided due to a higher average charge per monomer (or a higher particle fraction of ChS, the charged component of the polymer), low solute concentration in the bath, a high pH or a low cross-link fraction. A peculiar case arises at higher values of cross-link fraction, where it is observed that increasing the average charge per monomer leads to gel deswelling.

The effect of divalent vs. monovalent ions on the swelling of mucin-like polyelectrolyte gels: governing equations and equilibrium analysis.

We introduce a comprehensive model of a mucin-like polyelectrolyte gel swelling-deswelling which includes the ion-mediated crosslinking of polymer strands and the exchange of divalent and monovalent ions in the gel. The gel is modeled as a multi-phase mixture which accounts for the polymer and solvent volume fractions and velocities as well as ionic species concentrations. Motion is determined by force balances involving viscous, drag, and chemical forces. The chemical forces are derived from a free energy which includes entropic contributions as well as the chemical and electrostatic interactions among the crosslinked polymer, uncrosslinked polymer, and the ionic solvent. The unified derivation produces all the classical effects (van't Hoff osmotic pressure, Donnan equilibrium potential, Nernst-Planck motion of ions) as well as expressions for Flory interaction parameter and the standard free energy parameters that explicitly depend on the gel chemistry and crosslink structure. For this model, we show how the interplay between ionic bath concentrations, ionic binding, and transient divalent crosslinking leads to a variety of swelled and deswelled phases/phase transitions. In particular, we show how the absorption of divalent ions can lead to a massive deswelling of the gel. We conclude that the unique properties of mucin-like gels can be explained by their ionic binding affinities and transient divalent crosslinking.

Nonlinearity exponent of ac conductivity in disordered systems.

We measured the real part of ac conductance Σ(x,f) or Σ(T,f) of iron-doped mixed-valent polycrystalline manganite oxides LaMn(1-x)Fe(x)O(3) as a function of frequency f by varying initial conductance Σ(0) by quenched disorder x at a fixed temperature T (room) and by temperature T at a fixed quenched disorder x. At a fixed temperature T, Σ(x,f) of a sample with fixed x remains almost constant at its zero-frequency dc value Σ(0) at lower frequency. With increase in f, Σ(x,f) increases slowly from Σ(0) and finally increases rapidly following a power law with an exponent s at high frequency. Scaled appropriately, the data for Σ(T,f) and Σ(x,f) fall on the same universal curve, indicating the existence of a general scaling formalism for the ac conductivity in disordered systems. The characteristic frequency f(c) at which Σ(x,f) or Σ(T,f) increases for the first time from Σ(0) scales with initial conductance Σ(0) as f(c) ~ Σ(0)(x(f)), where x(f) is the onset exponent. The value of x(f) is nearly equal to one and is found to be independent of x and T. Further, an inverse relationship between x(f) and s provides a self-consistency check of the systematic description of Σ(x,f) or Σ(T,f). This apparent universal value of x(f) is discussed within the framework of existing theoretical models and scaling theories. The relevance to other similar disordered systems is also highlighted.

Relationship of possible stress-related biochemical markers to oxidative/antioxidative status in obsessive-compulsive disorder.

Free radicals have been found to play an important role in obsessive-compulsive disorder (OCD). So, we measured the oxidative/antioxidative status of OCD patients, and assessed its use as a biological marker. The study was carried out on 20 healthy and 20 OCD subjects, aged between 20 and 40 years. Biochemical parameters of all subjects were assessed and compared. A significant difference in superoxide dismutase (SOD) levels was observed between the OCD and control groups (p < 0.05); malondialdehyde (MDA) levels were also significantly higher in OCD subjects (p < 0.05). Our study found an overall oxidative imbalance in OCD, leaning towards the antioxidant side in sufferers (specifically towards SOD). SOD has a protective role in overcoming oxidative stress; therefore, oxidative stress could have a pathophysiological role in OCD. Therapy specifically targeting MDA production will have a beneficial effect in overcoming the oxidative stress, anxiety and affective disorder which may be associated with OCD.

Chemisorption of carbon dioxide on potassium-carbonate-promoted hydrotalcite.

New equilibrium and column dynamic data for chemisorption of carbon dioxide from inert nitrogen at 400 and 520 degrees C were measured on a sample of potassium-carbonate-promoted hydrotalcite, which was a reversible chemisorbent for CO(2). The equilibrium chemisorption isotherms were Langmuirian in the low-pressure region (p(CO(2)) < 0.2 atm) with a large gas-solid interaction parameter. The isotherms deviated from Langmuirian behavior in the higher pressure region. A new analytical model that simultaneously accounted for Langmuirian chemisorption of CO(2) on the adsorbent surface and additional reaction between the gaseous and sorbed CO(2) molecules was proposed to describe the measured equilibrium data. The model was also capable of describing the unique loading dependence of the isosteric heat of chemisorption of CO(2) reported in the literature. The column breakthrough curves for CO(2) sorption from inert N(2) on the chemisorbent could be described by the linear driving force (LDF) model in conjunction with the new sorption isotherm. The CO(2) mass-transfer coefficients were (i) independent of feed gas CO(2) concentration in the range of the data at a given temperature and (ii) a weak function of temperature. The ratio of the mass-transfer zone length to the column length was very low due to highly favorable CO(2) sorption equilibrium.

Correlation of autonomic indices with thyroid status.

The autonomic status in female thyroid patients was compared with healthy, age matched normal females taken as controls. The patients (29 +/- 7 years) were categorised into two groups: hyperthyroid and hypothyroid. The valsalva manoeuvre, standing to lying ratio (S/L ratio) and immediate heart rate response to standing (30:15 ratio) to assess the parasympathetic status while the galvanic skin response (GSR) was recorded to assess the sympathetic status. Statistical analysis was done using Student's t-test for comparing between the different groups and regression analysis were performed between autonomic indices and thyroid hormone levels. Although the mean values were not significantly different in hypothyroid and hyperthyroid patients, yet the correlation between autonomic function and thyroid hormone levels indicates a statistically significant difference (P-value<0.05), with the S/L ratio. The correlation was negative for log [T3] and log [T4], while it was positive for log [TSH]. This indicates that there is decreased parasympathetic activity with increased T3 and T4, which is in agreement earlier reports. The GSR, which is one of the measures of sympathetic activity, was found to be unaffected.

Task related changes in ERP auditory vs visual tasks.

P3 component of event related potentials have been studied in relaxed state of mind. Changes in P3 latency and amplitude are expected if measured after a rigorous mental exercise. The event related potentials (ERP) were measured in 20 normal male subjects aged between 18 and 22 years. ERP was recorded twice in each subject before and after the administration of a mental task. The auditory mental task comprised of repeating in reverse order string of random digits read out to the subject at a uniform speed of 1 per second. The visual task comprised reading laterally inverted type written text. Each subject had to undergo 2 sessions in separate sittings. The latency and amplitude of P300 recorded before and after the task were compared statistically using Students' unpaired t-test. There was significant increase in P3 latency following both visual and auditory tasks (auditory task: before 330 +/- 24.43 msec and after 342.9 +/- 27.66 msec, similarly visual task: before 333.2 +/- 26.66 msec and after 345.65 +/- 26.56 msec). All other ERP waves latency and amplitude changes were insignificant.

Shifts in information processing level: the speed theory of intelligence revisited.

A hypothesis is proposed here to reconcile the inconsistencies observed in the IQ-P3 latency relation. The hypothesis stems from the observation that task-induced increase in P3 latency correlates positively with IQ scores. It is hypothesised that: (a) there are several parallel information processing pathways of varying complexity which are associated with the generation of P3 waves of varying latencies; (b) with increasing workload, there is a shift in the 'information processing level' through progressive recruitment of more complex polysynaptic pathways with greater processing power and inhibition of the oligosynaptic pathways; (c) high-IQ subjects have a greater reserve of higher level processing pathways; (d) a given 'task-load' imposes a greater 'mental workload' in subjects with lower IQ than in those with higher IQ. According to this hypothesis, a meaningful comparison of the P3 correlates of IQ is possible only when the information processing level is pushed to its limits.

The effect of mutant peptide cofactors on adenovirus protease activity and virus infection.

Adenoviruses encode a cysteine protease, adenain, required for uncoating and virion maturation. Adenain activity is regulated by an 11-amino-acid peptide cofactor thiol-bonded distal to the active site. Structural and experimental data suggest that the peptide might stabilize adenain in an optimal conformation for enzyme activity by bridging two noncontiguous regions of the molecule. The sequence requirements for this mechanism were examined both in vitro and ex vivo by means of mutant peptides and databank analysis. The results of in vitro experiments suggested that activation is not an all or nothing mechanism. With the exception of the smallest peptide, the mutant peptides bound to adenain, activated it, and competed with the wild-type peptide, but all of this occurred with reduced efficiency. When added to the medium of infected cells, most of the peptides inhibited infectious virus production to varying degrees in a dose-dependent manner and in accordance with their in vitro activity on adenain. We interpret this inhibition to be due to unscheduled adenain activation. Examination of the activation peptide sequences from 19 adenovirus serotypes revealed a limited number of conserved sequence features. These features were in agreement with the experimental data. We conclude that binding and activation of adenain by pVIc may be reversible and this reversibility may be an integral aspect of the in vivo regulation of enzyme activity in the course of virus assembly. The peptide cofactor binding domain is therefore a potential target for the development of anti-adenoviral agents.

Adenovirus endopeptidase hydrolyses human squamous cell carcinoma antigens in vitro but not ex vivo.

The serpins SCCA1 and SCCA2 are highly expressed in the epithelium of the conducting airways, a common site of infection by group C adenoviruses, such as human adenovirus type 2 (Ad2). Based on the common location we examined a possible interaction between them. In vitro experiments with recombinant proteins showed that SCCA1 inhibited the viral protease in a dose-dependent manner. Both serpins were cleaved in a manner consistent with hydrolysis within their reactive site loop, without the formation of an SDS-resistant complex, as in the case of papain. Infection of SCCA1-expressing cells did not result in the cleavage of SCCA1, nor was the yield of infectious virus affected as compared to SCCA1-negative parental cells. This may be due to differential localization, the serpin being cytoplasmic and viral protease being nuclear. Surprisingly, however, virus infection, which tends to inhibit host protein synthesis, caused a significant increase in SCCA1 expression well into the late phase of infection.

Cytohistological study of urinary bladder neoplasms.

Eighty patients presenting with painless hematuria and 24 patients of transitional cell carcinoma bladder coming for follow up were included in this study to assess the role of exfoliative (voided urine) and lavage (saline lavage) cytology in initial diagnosis and follow up of the patient with carcinoma bladder. Freshly voided urine samples and saline lavage bladder washing samples were collected. A thorough cystoscopic examination was done and biopsy was taken from any apparent growth. Cytological smears were stained with hematoxylene and eosin and PAP's stain, histology sections were stained with hematoxylene and eosin. A statistically significant correlation (p < 0.001) was observed between the increasing grade of malignancy and cytopositivity. A good association was observed between histology and two methods of cytology (p < 0.01). The sensitivity, specificity and overall diagnostic accuracy of lavage cytology was more as compared to exfoliative cytology (71.05%, 56.0%, 78.85% Vs 47.37%, 41.18% and 61.54%). Cystopositivity was more with single large sessile tumour as compared to multiple small pedunculated tumours. Cytohistological discrepancy was observed in patients of transitional cell carcinoma with recurrence. It is concluded that cytology may act as a good adjuvant to histology in picking up early flat lesions and/or follow up of patients with transitional cell carcinoma.

Isosteric Heat of Adsorption: Theory and Experiment.

The isosteric heats of adsorption of the components of a gas mixture are critical variables for design of adsorbers for gas separation. They can be unambiguously defined by the Gibbsian Surface Excess (GSE) model of multicomponent adsorption. These variables can be experimentally measured by multicomponent differential calorimetry (MDC) and directly used to describe nonisothermal behavior of practical adsorbers. There is no need to make simplified assumptions about the nature and size of the adsorbed phase, as required by conventional adsorption thermodynamic models, to define the isosteric heats. Pure gas isosteric heats of adsorption of N2 and CO2 on a pelletized silicalite sample were measured using a MDC and a data analysis algorithm based on the GSE model. The silicalite sample behaved like a homogeneous adsorbent for weakly polar N2 adsorption. The presence of polar alumina binder in the silicalite sample introduced significant heterogeneity for more polar CO2 adsorption.

Involving students in question writing: a unique feedback with fringe benefits.

A contest on question writing was organized during the undergraduate medical physiology teaching program. Students were asked to write and submit multiple-choice questions of the assertion-reasoning type (type E) in physiology. The winners were decided after the questions submitted were graded on a six-point scale (0-5) that considered both thematic novelty and construct correctness. Of the 100 students in the class, 37 participated in the contest, and a total of 912 questions was received. The contest encouraged the students to go through their subjects critically. The questions provided the instructor with insight into the learning habits and misconceptions of the students and provided the grist for animated discussions in tutorial classes. Although several types of errors were deciphered in these questions, with suitable modifications the questions helped the faculty build up a sizable question bank.

POST-TASK EVENT-RELATED-POTENTIAL (ERP) CORRELATES OF PSYCHOMETRIC INTELLIGENCE.

The standard psychometric scores show a fair degree of correlation with event-related evoked potential (ERP) latencies and amplitude. Since, both latency and amplitude are known to change during mental activity, it becomes important to consider both pre- and post-task ERP parameters is such correlative studies. In the present study, we have compared the psychometric scores obtained through WAIS-PR with evoked potential latencies and amplitude recorded at 2 sessions, one before, and the other immediately after a brief period of rigorous mental task. A negative corrrelation (-0.4) was found between the IQ of a subject and his P300 latency. Moreover, there was a positive correlation (+0.4) between the IQ of a subject and the latency changes of his P300 following mental exercise (post-task P300 latency minus pre-task P300 latency). Hence, there appears to be a reserve in 'latency increase' proportional to the IQ, which is manifest only following a mental task.

Adenovirus endopeptidase and papain are inhibited by the same agents.

Adenoviruses encode a cysteine protease (AVP) which carries out highly specific cleavages on at least seven viral proteins and two cellular proteins. Virus infectivity is dependent on this function. The three-dimensional positions of the amino acids involved in catalysis display a striking similarity to those of papain, suggesting a similar catalytic mechanism. This similarity has prompted us to compare the effect of papain inhibitors on the two enzymes. AVP and papain activity was tested on a fluorescent peptide substrate as well as on metabolically labeled adenovirus (Ad2) precursor proteins. Hep2 cells infected with Ad2 were exposed to inhibitors and assayed for, (a) infectious virus, (b) in situ Ad2 protease activity, (c) physical particle production and their polypeptide composition. We found that in both substrate systems AVP was sensitive to the papain inhibitors benzamidoacetonitrile, acetamidoacetonitrile and N-methoxyphenylalanine glycylnitrile, and that the degree of sensitivity was influenced by the substrate. Unlike papain, AVP was relatively insensitive to E64. In ex vivo tests, Hep2 cells infected with Ad2 were exposed to inhibitors and assayed for, (a) infectious virus, (b) in situ Ad2 protease activity, (c) physical particle production and their polypeptide composition. A 4-fold reduction in virus titer was obtained when the inhibitors were added between 17 and 25 h after infection. Processing of precursor proteins was also inhibited yet the production of physical particles was only reduced 2-fold. These experiments show that papain inhibitors are also capable of inhibiting the adenovirus protease both in vitro and ex vivo, thus forging a possible link between structural similarity and functionality.

Using simple animations in physiology teaching: ventilatory patterns. A case in point.

Constructing diagrams to explain certain physiological concepts can be challenging. There is a whole class of physiological topics, represented here by the neural generation of respiratory rhythm, that are best taught using "dynamic diagrams," a series of diagrams generated through simple animations and based on user-provided inputs. The theory of neural generation of respiratory rhythm discussed here is not necessarily correct or widely read accepted. It continues to find a place, however, in some of the most widely read textbooks of physiology, which obligates the teacher to devise effective methods of putting it across to the students. Selected criteria can be defined for identifying areas in which dynamic diagrams would be effective as a teaching tool. Unlike those animations that are used to provide a debatable alternative to wet laboratory, dynamic diagrams explaining certain theoretical concepts should have few rivals.