Optimal diagnostic tool for surveillance of oesophageal varices during COVID-19 pandemic.

AIM: To study the diagnostic accuracy and utility of triphasic abdominal computed tomography (CT) in the diagnosis and grading of oesophageal varices (OVs) as an alternative to endoscopy during the COVID-19 pandemic. MATERIALS AND METHODS: A prospective analysis was undertaken of retrospective data from cirrhotic patients who underwent oesophago-gastro-duodenoscopy (OGD) and a triphasic abdominal CT from January to December 2019. Endoscopists and radiologists provided their respective independent assessment of OV grading after being blinded to the clinical details. Performance of CT grading of OVs was compared with the reference standard endoscopic grading using weighted kappa (k). Non-invasive scores such, as aspartate transaminase (AST)-to-platelet ratio index (APRI), Fibrosis-4 (FIB-4) Index, platelet: spleen (PS) ratio were correlated between the two techniques. RESULTS: OV grading between endoscopists and radiologists showed 81.73% agreement (85 out of 104 patients) in the comparative analysis of 104 cirrhotic patients, of which no varices (57.1%, n=4), small (85.1%, n=23), medium (72.2%%, n=26), and large varices (94.1%, n=32) with a weighted k score of 0.88 (95% confidence interval 0.82-0.94). Overall, the sensitivity of CT in the diagnosis of no, small, medium, and large OVs was 66.6%, 79.3%, 89.6%, and 94.1%, respectively, with an area under the receiver operating curve (AUROC) score of 0.775, 0.887, 0.839, and 0.914. Performance of APRI, FIB-4, and PS ratio correlated well with the severity of OVs with no difference between OGD and CT grading. CONCLUSION: Triphasic abdominal CT can be an invaluable tool in the diagnosis and grading of OVs during the COVID-19 pandemic.

Spiking Elementary Motion Detector in Neuromorphic Systems.

Apparent motion of the surroundings on an agent's retina can be used to navigate through cluttered environments, avoid collisions with obstacles, or track targets of interest. The pattern of apparent motion of objects, (i.e., the optic flow), contains spatial information about the surrounding environment. For a small, fast-moving agent, as used in search and rescue missions, it is crucial to estimate the distance to close-by objects to avoid collisions quickly. This estimation cannot be done by conventional methods, such as frame-based optic flow estimation, given the size, power, and latency constraints of the necessary hardware. A practical alternative makes use of event-based vision sensors. Contrary to the frame-based approach, they produce so-called events only when there are changes in the visual scene. We propose a novel asynchronous circuit, the spiking elementary motion detector (sEMD), composed of a single silicon neuron and synapse, to detect elementary motion from an event-based vision sensor. The sEMD encodes the time an object's image needs to travel across the retina into a burst of spikes. The number of spikes within the burst is proportional to the speed of events across the retina. A fast but imprecise estimate of the time-to-travel can already be obtained from the first two spikes of a burst and refined by subsequent interspike intervals. The latter encoding scheme is possible due to an adaptive nonlinear synaptic efficacy scaling. We show that the sEMD can be used to compute a collision avoidance direction in the context of robotic navigation in a cluttered outdoor environment and compared the collision avoidance direction to a frame-based algorithm. The proposed computational principle constitutes a generic spiking temporal correlation detector that can be applied to other sensory modalities (e.g., sound localization), and it provides a novel perspective to gating information in spiking neural networks.

Modulatory effect of dietary factors on iron-induced in vivo lipid peroxidation in liver and serum of albino rats.

Effect of a computed diet based on cereals and spices incorporated with either crude palm oil (CPO)/soybean oil (SBO)/cod liver oil (CLO) at 10% level in the diet in modulating iron-induced in vivo lipid peroxidation was carried out during a 12 week study in albino rats. Three groups of rats, each divided into three sets were fed diets based on casein/ragi/jowar incorporated with CPO or SBO or CLO. The casein group of rats did not receive any spice mixture, while the ragi and jowar groups received spice mixture at 2.5% level. Serum lipid analysis showed significant increase in cholesterol, LDL-c + VLDL-c and decrease in HDL-c levels in all the iron treated group of animals. In liver, non-significant increase in total cholesterol triglyceride and decrease in phospholipid levels were noted. Fatty acid profile of liver tissue exhibited low 18:2 levels in various experimental groups due to peroxidation of membrane lipids. Histopathological examination of liver tissue in particular showed mild cytoplasmic vacuolation in control group of rats fed ragi/jowar and moderate vacuolation in all the iron-treated groups. The results demonstrate that different dietary components can beneficially modulate free radical mediated oxidative stress induced by lipid peroxidation.

The Schistosoma mansoni epidermal growth factor receptor homologue, SER, has tyrosine kinase activity and is localized in adult muscle.

DNA encoding the full-length Schistosoma mansoni epidermal growth factor receptor, SER, was obtained by combining partial cDNA clones. Three different anti-SER antibody preparations, specific either to the SER amino-terminus or the predicted ligand binding domain were generated with recombinant or synthetic peptides and purified by antigen affinity. Recombinant SER was expressed within insect cells using the baculovirus expression system and detected by each of the anti-SER antibodies as well as anti-phosphotyrosine antibodies. By in vitro phosphorylation of immunoprecipitated recombinant SER, the protein has been shown to be capable of tyrosine autophosphorylation but this activity is not affected by human epidermal growth factor. Native SER is detected as a 170 kDa protein in Western blots of S. mansoni adult worm membrane preparations. Adult worm sections, labeled with anti-SER antibodies, localize SER predominantly to the muscle of adult male and female worms. These results confirm a place for SER in the EGFR family of tyrosine kinases and strongly suggest that it participates in schistosome signal transduction, perhaps related to muscle development or function.

Alternative splicing of the Schistosoma mansoni gene encoding a homologue of epidermal growth factor receptor.

The complete coding DNA for a Schistosoma mansoni homologue of the epidermal growth factor receptor (SER) was characterized from cDNA clones obtained by homology to the tyrosine kinase domain of erbB. The DNA sequence predicts a 200-kDa translation product that contains a secretory leader, a cysteine-rich extracellular domain, a hydrophobic transmembrane sequence, and an intracellular tyrosine kinase domain. The SER transcript is present in cercariae and adult schistosomes. In addition to SER transcripts, schistosomes produce at least 3 variant transcripts encoding truncated SER products that include the secretory leader and a small portion of the extracellular domain followed by short sequences of unrelated, C-terminal amino acids. Based on these sequences, 2 of the variant mRNAs (class 2 and 5) appear to encode soluble, secreted proteins while one (class 4) encodes an SER variant protein with a hydrophobic C-terminus that may serve as a membrane anchor. Class 2 SER variant transcripts are present at levels comparable to SER transcripts in adult worms but are not detected in cercariae. Class 4 and 5 SER variant transcripts are also found within adult worms but at lower levels. Genomic cloning and characterization demonstrate that the variant SER transcripts arise through alternative splicing of the SER gene.

Movement for medical treatment. A study in contact patterns of a rural population.

This paper deals with the patterns of movement of rural population for purposes of medical treatment. The following hypothesis are empirically tested with the data on 245 randomly selected sample villages containing about 30,000 households in Tumkur District of Karnataka (India). (a) There are significant differences in the incidence of sickness between various socio-economic groups. (b) The poorer sections of the rural society tend to get treated by informal/traditional systems of medicine. (c) Since the available medical facilities are few, no significant differences are observable in the distance travelled by different socio-economic groups. (d) The actual places of visit for treatment may be different for different socio-economic groups, since the society consists of 'status-conscious' population. (e) The long distance movement is not a matter of travel costs but essentially of overhead costs at the places of treatment. The analysis reveals that hypothesis (c), (d) and (e) are valid. Invalidation of hypothesis (a) raises the question of perception of sickness among the various strata of the society, whereas invalidation of hypothesis (b) indicates the use of allopathic system by all sections of rural population. In terms of location planning of medical services, the study indicates that two levels may be thought of--neighbourhood facilities and higher order facilities--rather than a hierarchy of medical centres involving a number of intermediary levels. Middle level centres are found to be under utilised since the patients tend to bypass them to avail of medical services of higher order centres.

Structure of a source-driven magnetized oblique presheath.

A source-driven magnetized presheath is analyzed in an obliquely incident magnetic field. The conventional fluid treatments of the collisionless and collisional magnetized presheath use standard fluid equations to recover the velocity profiles that satisfy the Bohm sheath criterion at the electrostatic sheath edge. In a purely source-driven collisionless presheath, however, there is no mechanism to redistribute the change in parallel energy in the perpendicular direction and therefore the boundary values of flow velocities are strong functions of angle of incidence. In the present treatment, numerical solutions are obtained for a set of fluid equations derived from the moment description of a generalized gyrokinetic equation. The density, velocity, and temperature profiles in a source-driven presheath are computed, which show a dependence on the angle of incidence of the magnetic field on a perfectly absorbing solid surface.

Effect of oxidative stress on serum and antioxidant enzymes in liver and kidney of rats and their modulation through dietary factors.

Modulatory effect of a formulated diet based on cereals, pulses and spices incorporated with crude palm oil (CPO), soybean oil (SBO) or cod liver oil (CLO) at 10% dietary level on oxidative stress and antioxidant enzymes was studied in liver and kidney tissues. Activity of alkaline phosphatase (ALP) and acid phosphatase (ACP) increased significantly in serum in various experimental groups. Significant increase in hepatic antioxidant enzymes, catalase, glutathione peroxidase (GPx) was also seen in the experimental groups. SOD activity showed a mixed response. Further, kidney antioxidant enzymes did not show much change compared to those in liver. The results indicated dietary lipid as the key players in determining cellular susceptibility to oxidative stress, which could be modulated by cereals, pulses and spices in the diet.

UNUSUAL BILIARY FISTULA.

Agenesis of gall bladder is a clinical rarity, as most of the diagnoses are made at autopsy. Preoperative diagnosis of this anomaly is fraught with follies. External biliary fistulae are usually result of complications of trauma or biliary surgery. Internal fistulae on the other hand may result from erosion of wall by a stone, cancerous growth or peptic ulcer. Sites of opening of internal fistulae are stomach, duodenum, jejunum, ileum or colon. These should be suspected if gas shadows are seen in biliary tree.

Use of a graded gain random amplifier as an optical diode.

The spectral characteristics of liquid amplifying media have been used to design and experimentally realize an optical device that prevents the propagation of a band of wavelengths in one direction and permits it in the opposite direction, thus acting as an optical diode. The addition of random scattering centers is shown to narrow the width of the forbidden band. A model is proposed to explain the observations and is verified by Monte Carlo simulations.

Lasing in active, sub-mean-free path-sized systems with dense, random, weak scatterers.

We report enhanced emission and gain narrowing in Rhodamine 590 perchlorate dye in an aqueous suspension of polystyrene microspheres. A systematic experimental study of the threshold condition for and the gain narrowing of the stimulated emission over a wide range of dye concentrations and scatterer number densities showed several interesting features, even though the transport mean free path far exceeded the system size. The conventional diffusive-reactive approximation to radiative transfer in an inhomogeneously illuminated random amplifying medium, which is valid for a transport mean-free path much smaller than the system size, is clearly inapplicable here. We propose a new probabilistic approach for the present case of dense, random, weak scatterers involving the otherwise rare and ignorable sub-mean-free-path scatterings, now made effective by the high gain in the medium, which is consistent with experimentally observed features.

Long-term feeding effects of heated and fried oils on hepatic antioxidant enzymes, absorption and excretion of fat in rats.

Long-term feeding effect of heated and fried peanut (PNO), rice bran (RBO) and palm oil (PO) in the diet on the hepatic antioxidant enzyme status and absorption and excretion of fats were studied in laboratory rats. The rats were fed oils heated to 180 degrees C continuously for a period of 72 h or laboratory fried at 20% level in the diet for 18 weeks. The results of the study indicated a significant increase in the catalase activity in HO groups and decrease in the FRO groups. The GPx activity while significantly low in HO groups was high in FRO groups, whereas, significant decrease in GST activity was observed in both PNO-HO/FRO groups. Increased activity was noted in RBO-FRO and PO-HO/FRO groups. The SOD activity showed a mixed response in different heated/fried oils and a marginal increase in the levels of fecal fat excretion was observed in some of the heated/fried oil groups. The results indicated no appreciable damage with respect to these antioxidant enzymes. Also, feeding heated fats as high as 20% in the diet for long duration does not result either in reduced food intake or excess fecal fat excretion.

Substitution of murine for human CD4 residues identifies amino acids critical for HIV-gp120 binding.

Human CD4 is the receptor for the gp120 envelope glycoprotein of human immunodeficiency virus and is essential for virus entry into the host cell. Sequence analysis of CD4 has suggested an evolutionary origin from a structure with four immunoglobulin-related domains. Only the two NH2-terminal domains are required to mediate gp120 binding. The extracellular segment of murine CD4 has an overall 50% identity with its human counterpart at the amino-acid level, but fails to bind gp120. To define those residues of human CD4 critical for gp120 binding, we have taken advantage of this species difference and substituted all non-conserved murine for human CD4 residues between amino-acid positions 27-167. We used oligonucleotide-directed mutagenesis to create each of 16 individual mutant human CD4 molecules containing from 1-4 amino-acid substitutions. Introduction of as few as three amino acids into corresponding positions of human CD4 abrogates gp120 binding. Furthermore, these critical residues are located in domain I with a contribution from domain II. Modelling studies using the three-dimensional coordinates of the V kappa Bence-Jones REI homodimer localize the site in domain I to the C" beta strand within CDR2 but projecting away from the homologues of principle antigen-binding regions CDR 1 and 3.

A short isoform of Col9a1 supports alveolar bone repair.

Bone wound created in intramembranous alveolar bone heals without the formation of cartilage precursor tissue. However, the expression of cartilage collagen mRNAs has been suggested. In this report, we examined the expression and the potential role of type IX collagen in bone restoration and remodeling. The sequence specific polymerase chain reaction demonstrated the exclusive expression of short transcriptional isoform of alpha1(IX) collagen (Col9a1) in alveolar bone wound healing, while the long isoform of Col9a1 transcript was absent. Type IX collagen was immunolocalized in the preliminary matrix organized in granulation tissue before trabecular bone formation in tooth extraction socket. In Col9a1-null mutant mice, there were considerable variations in alveolar bone wound healing with the absence of or abnormally organized trabecular bone. Occasionally, unusual apposition of cortical-bone-like layers in bone marrow space was observed. The Col9a1-null mice indicated no growth retardation, and their facial and long bones maintained the normal size and shape. However, the primary spongiosa region of adult Col9a1 mutant mice showed an abnormal trabecular bone structure associated with abnormal immunostaining with the hypertrophic cartilage specific type X collagen antibody. These data suggest that type IX collagen short transcriptional variant is involved in the restoration and remodeling processes of trabecular bone.

The gene for T11 (CD2) maps to chromosome 1 in humans and to chromosome 3 in mice.

The chromosomal locations of the human and murine T11 (CD2) gene have been determined. Using recently cloned cDNA to probe Southern blots of mouse X human and Chinese hamster X mouse somatic cell hybrids, we have localized the human T11 gene to chromosome 1 and the murine T11 gene to chromosome 3. Based on previously determined blocks of homology between human chromosome 1 and mouse chromosome 3, it is suggested that the human T11 gene may lie on the short arm of chromosome 1 proximal to p221. Thus, the T11 gene is not linked to any other genes for T cell markers that have been mapped to date.