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Biomedical subjects

Deepti Chaturvedi

Publications and source records attributed to Deepti Chaturvedi.

11 recordsLinked to original sources

Effectiveness of a digi-physical tool and working method for paediatric obesity treatment in Abu Dhabi: a non-inferiority intervention study using an external historical comparator.

BACKGROUND: Effective paediatric obesity treatment requires high intensity, scalable interventions. A digi-physical tool for paediatric obesity treatment has shown positive results in Stockholm, Sweden. This study evaluates whether the same treatment method is effective in a different cultural setting. METHODS: This non-inferiority intervention study, using an external historical comparator, included 60 consecutively recruited children aged 6-15.9 years with obesity who initiated treatment at Sheikh Shakhbout Medical City in Abu Dhabi between June and December 2023. Patients were treated with Evira, a digi-physical tool and working method enabling high intensity individualized care, real-time monitoring, and interactive patient-clinician communication. The primary outcome was BMI z-score change at 26 weeks. Non-inferiority was assessed using a predefined margin of 0.10 BMI z-score, with outcomes compared to a prior published trial in Stockholm (n = 107). RESULTS: A total of 112 children were included in the analysis (Abu Dhabi cohort, n = 35; Stockholm cohort, n = 77). The adjusted mean change in BMI z-score was - 0.20 (95% CI: - 0.28, - 0.12) in the Abu Dhabi cohort and - 0.20 (- 0.26, - 0.14) in the Stockholm cohort (p = 0.88). Non-inferiority was confirmed, (predefined margin 0.10 was not exceeded). A clinically significant BMI z-score reduction (≥ 0.20 units) was achieved by 45.7% of participants in Abu Dhabi and 36.4% in Stockholm (p = 0.35). Non-retention rates at 26 weeks were 41.7% vs. 28.0%, respectively (p = 0.07). CONCLUSIONS: The findings provide promising evidence that treatment outcomes achieved with the digi-physical treatment tool were comparable in the Abu Dhabi and Stockholm cohorts, supporting its feasibility in a second cultural and healthcare setting.

Humans↗

Subcellular localization and biological actions of activated RSK1 are determined by its interactions with subunits of cyclic AMP-dependent protein kinase.

Cyclic AMP (cAMP)-dependent protein kinase (PKA) and ribosomal S6 kinase 1 (RSK1) share several cellular proteins as substrates. However, to date no other similarities between the two kinases or interactions between them have been reported. Here, we describe novel interactions between subunits of PKA and RSK1 that are dependent upon the activation state of RSK1 and determine its subcellular distribution and biological actions. Inactive RSK1 interacts with the type I regulatory subunit (RI) of PKA. Conversely, active RSK1 interacts with the catalytic subunit of PKA (PKAc). Binding of RSK1 to RI decreases the interactions between RI and PKAc, while the binding of active RSK1 to PKAc increases interactions between PKAc and RI and decreases the ability of cAMP to stimulate PKA. The RSK1/PKA subunit interactions ensure the colocalization of RSK1 with A-kinase PKA anchoring proteins (AKAPs). Disruption of the interactions between PKA and AKAPs decreases the nuclear accumulation of active RSK1 and, thus, increases its cytosolic content. This subcellular redistribution of active RSK1 is manifested by increased phosphorylation of its cytosolic substrates tuberous sclerosis complex 2 and BAD by epidermal growth factor along with decreased cellular apoptosis.

A Kinase Anchor Proteins↗

A historical perspective of the EGF receptor and related systems.

Since the isolation of epidermal growth factor (EGF) from mouse submaxillary glands in the early 1950s by Cohen and coworkers, this growth factor has been shown to have various effects on numerous cellular systems. The biological and physiological role that EGF plays during development and in adult animals led to the identification of its receptor (EGFR) as well as the other members of the EGF family of growth factors and their receptors. In this chapter we provide a historical overview of the discovery of EGF, identification of the other members of EGF family, early studies on the actions of EGF, as well as the discovery and structural characterization of its receptor. Further, we have reviewed the transactivation of the EGFR by agonists for G protein-coupled receptors (GPCRs) and other extracellular stimuli unrelated to EGF-like ligands. Finally, an overview of the role of the EGFR family members in various diseases, including different forms of cancer, is provided.

Animals↗

Analysis of EGF receptor interactions with the alpha subunit of the stimulatory GTP binding protein of adenylyl cyclase, Gs.

Besides stimulating the mitogen-activated protein kinase, phospholipase Cgamma, and phosphatidylinositol 3-kinase cascades, in certain tissues and cells such as the heart, partotid gland, and luteal cells, activation of the epidermal growth factor (EGF) receptor also stimulates second-messenger systems that involve the heterotrimeric G proteins. For instance, in the heart EGF increases contractility and heart rate by elevating cellular cyclic adenosine monophosphate (cAMP) levels. This is the result of EGF-elicited activation of adenylyl cyclase via the stimulatory guanosine 5'-triphosphate (GTP)-binding protein Gs. In this context, the single transmembrane EGF receptor acts like a heptahelical G protein-coupled receptor. Here we have described the methods used to study interactions between the EGF receptor and heterotrimeric G proteins. Moreover, we have also described how the stoichiometry of EGF receptor association with the alpha subunit of Gs can be monitored in vitro. Several other single transmembrane receptors and proteins can also activate heterotrimeric G proteins, and, therefore, the methodologies described in this chapter can be adapted to other systems.

Adenylyl Cyclases↗

Regulation of vascular smooth muscle cell proliferation and migration by human sprouty 2.

OBJECTIVE: To determine whether the human sprouty 2 (hSPRY2) protein, an inhibitor of receptor tyrosine kinase actions, regulates vascular smooth muscle cell (VSMC) proliferation, migration, and neointima formation in injured carotid artery. METHODS AND RESULTS: The hSPRY2 protein or green fluorescent protein (GFP; control) was transduced into VSMCs by placing an N-terminal TAT epitope on the proteins. The transduction of TAT-tagged hSPRY2 (TAT-hSPRY2) but not TAT-GFP inhibited the ability of serum and different growth factors to stimulate migration of VSMCs. Likewise, TAT-hSPRY2 also inhibited VSMC proliferation in response to serum. The hSPRY2 microtubule association (amino acids 123-177) and membrane translocation (amino acids 178-194) domains were necessary for the biological actions of hSPRY2. In the rat carotid artery injury model, exposure of the injured vessel for 1 hour to TAT-hSPRY2, but not TAT-GFP, markedly inhibited growth of the neointima over the 28-day postangioplasty period as well as VSMC proliferation. The exogenously applied TAT-hSPRY2 was retained in the carotid arteries for at least 3 days after injury, and endogenous SPRY2 expression was maximized around day 14 after injury. The latter is perhaps a compensatory mechanism to regulate neointima formation. CONCLUSIONS: We conclude that TAT-tagged proteins are efficiently transduced into VSMCs in vitro and in vivo, that hSPRY2 inhibits growth and migration of VSMCs, and that this protein can decrease neointimal growth after blood vessel injury.

Animals↗

Drosophila wnt-1 undergoes a hydrophobic modification and is targeted to lipid rafts, a process that requires porcupine.

Wnt signaling pathways regulate many developmental responses; however, little is known about how Wnt ligands function on a biochemical level. Recent studies have shown that Wnt-3a is palmitoylated before secretion. Here we report that Drosophila Wnt-1 (Wingless) also undergoes a lipid modification. Lipidation occurs in the endoplasmic reticulum and is dependent on Porcupine, a putative O-acyltransferase. After modification, DWnt-1 partitions as a membrane-anchored protein and is sorted into lipid raft detergent-insoluble microdomains. Lipidation, raft targeting, and secretion can be blocked by the addition of 2-bromopalmitate, a competitive inhibitor of O-acyltransferase activity. Based on these results we propose a model whereby lipidation targets Wnt-1 to secretory vesicles that deliver the ligand to specialized microdomains at the cell surface where it can be packaged for secretion.

Animals↗

Comparison of axillary temperature with rectal or oral temperature and determination of optimum placement time in children.

The present study was done to compare axillary temperature (AT) with rectal temperature (RT) in 100 infants and with oral temperature (OT) in 100 children agd 6 to 12 years and also to find out the optimum placement time of the mercury thermometer at the above sites. Simultaneous AT and RT recording was done in infants while sequential AT and OT recording was done in older children by different investigators using calibrated Hick thermometers. The placement time recorded was when 3 consecutive readings at one minute interval remained unchanged. Significant correlation was observed between RT and AT (r=0.95, p <0.01) and between OT & AT (r = 0.97, p 0 <0.01). Equations were derived to calculate RT & AT from AT. The mean placement time for RT, AT and OT was 2.3 minutes, 4.8 minutes and 3.1 minutes respectively. The study showed a high degree of correlation between OT or RT and AT.

Axilla↗

Restriction-modification system in bacteriophage MB78.

Restriction-modification system is present in bacteria to protect the cells against phage infection. Interestingly, the bacteriophage MB78, a virulent phage of Salmonella typhimurium possesses restriction-modification system. Permissive host transformed with plasmid having the genomic fragment of MB78 carrying the putative restriction-modification genes severely restrict the growth of the phage 9NA. Growth of phage MB78 is also restricted to some extent. However, the temperate phage P22 is not restricted at all. Cloning of the the putative restriction-modification genes has been done in both orientations in different vectors. The clones carrying the genes in the same orientation as that of the lacZ in pUC19 are mostly unstable. However, those are stable when cloned in opposite orientation. Viability of the transformants is strain-, orientation-, and medium-dependent. The two genes have also been cloned individually/separately. Hosts carrying only the modification gene do not restrict growth of phages while the hosts carrying only the restriction gene do. The former produces stable transformants while the latter produces very unstable transformants which were viable only upto 36 h or so. The colonies carrying modification gene were normal looking while those carrying the restriction gene were tiny, flat, and looked distressed resembling very much the clones carrying bacterial restriction-modification system. Amplification of the genes and subsequent cloning in expression vector will be carried out for characterization of the enzymes.

Base Sequence↗

Reliability of perception of fever by touch.

OBJECTIVE: To assess the reliability of touch to predict fever in children. METHODS: 200 children who reported with fever formed the study material. Group I consisted of 100 children between 0-1 year of age and Group II consisted of 100 children between 6-12 years of age. Preterm, neonates under warming device, tachypnoeic and hypothermic were excluded from the study. The caregiver (CG) and the medical staffs (MS) response regarding presence or absence of fever by touch was noted in each child. Both were blinded to each other's response. Immediately temperature was recorded by calibrated rectal thermometer in Group I and calibrated axillary thermometer in Group II. RESULTS: The CG's touch had a sensitivity of 70.5% specificity of 40.9%, PPV of 38% NPV of 72.9%, PLR was 1.16 and NLR was 0.75. The MS's touch had a sensitivity of 78.0%, specificity of 63.6%, PPV of 38.0% NPV 84.8%, PLR of 2.08 and NLR of 0.36. There is over and under diagnosis of fever by both, the former being more by the CG reflecting the parental anxiety. The MS's touch is better to affirm or negative fever as compared to CG. The best site to palpate for presence of fever was abdomen, neck and forehead. CONCLUSION: Touch is not a valid screening test for fever. It is recommended that a thermometer must always be used by the MS to record fever and CG must be motivated for the same.

Child↗

Expression of subunits for the cAMP-sensitive 'olfactory' cyclic nucleotide-gated ion channel in the cochlea: implications for signal transduction.

Cyclic nucleotide-gated (CNG) ion channels have been implicated as functioning in sensory transduction and in second-messenger modulation of synaptic neurotransmitter release. The olfactory, cAMP-sensitive CNG ion channel in vivo is considered to comprise the pore-forming CNG2 subunit together with CNG5 and CNG4.3 modulatory subunits. The expression of these 'olfactory' CNG subunit transcripts in microdissected subfractions of the rat cochlea and hair cell libraries has been investigated with RT-PCR. Unmodified transcripts of CNG2 were detected in the organ of Corti, lateral wall and spiral ganglion subfractions. CNG5 message was found in both the sensory organ of Corti and the non-sensory lateral wall subfractions but not in the spiral ganglion subfraction. The CNG5 sequence obtained for the organ of Corti fraction encompassed 78% of the olfactory CNG5 cDNA sequence. CNG5 message has also been detected in an inner hair cell cDNA library. In the lateral wall, unmodified CNG5 sequence was observed as well as truncated versions of CNG5 transcripts, one of which was also found in the rat brain. The truncated versions were characterized by deletions that resulted in a shift in reading frame and the premature appearance of a stop codon. The 'olfactory' CNG4.3 cDNA was amplified from all three subfractions. Within the cochlea, CNG2 immunoreactivity was selectively distributed in a pattern similar to that of adenylyl cyclase type I. Immunoreactivity to CNG2 has been localized to stereocilia of inner hair cells. CNG5 immunoreactivity was associated with stereocilia and lateral plasma membranes of outer hair cells. We conclude that transcripts necessary for a functional cAMP-sensitive CNG ion channel are present in the cochlea resulting from combinations of CNG2 with CNG5 and CNG4.3. Further, the localization of CNG2 and CNG5 immunoreactivity to hair cell stereocilia suggests a role for cAMP-sensitive CNG channels in hair cell signal transduction.

Adenylyl Cyclases↗