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PubMed1996

Identification of an autoinhibitory region in the activation loop of the Mos protein kinase.

The Mos protein is a serine/threonine protein kinase which acts to regulate progression through meiosis in vertebrate oocytes. Although Mos function is dependent on its ability to act as a protein kinase, little is known about the factors which regulate Mos kinase activity. To understand the mechanism by which Mos kinase activity is regulated, we have used molecular modeling to construct a three-dimensional model of Mos based on the crystallographic coordinates of cyclic AMP-dependent kinase (PKA). This model identified a loop in Mos which is positioned near the active site and appears capable of blocking substrate access to the active site. Mutagenesis was used to construct altered forms of the Mos protein with deletions of parts or all of the loop. In vitro kinase assays showed that Mos proteins with the loop removed had up to a fourfold increase in kinase activity compared with the wild-type protein, indicating that the loop acts in an autoinhibitory manner for Mos kinase activity. Point mutations were also made on individual residues of the loop which were determined from the molecular model to be capable of reaching the active site. Determination of the kinase activities of these mutants showed that individual mutations in the loop region are capable of either increasing or decreasing kinase activity with regard to the wild-type protein. These data suggest that the loop identified in Mos acts as an autoinhibitor of kinase activity.

Amino Acid Sequence↗

PubMed1999

Conserved loop I of U5 small nuclear RNA is dispensable for both catalytic steps of pre-mRNA splicing in HeLa nuclear extracts.

The function of conserved regions of the metazoan U5 snRNA was investigated by reconstituting U5 small nuclear ribonucleoprotein particles (snRNPs) from purified snRNP proteins and HeLa or Xenopus U5 snRNA mutants and testing their ability to restore splicing to U5-depleted nuclear extracts. Substitution of conserved nucleotides comprising internal loop 2 or deletion of internal loop 1 had no significant effect on the ability of reconstituted U5 snRNPs to complement splicing. However, deletion of internal loop 2 abolished U5 activity in splicing and spliceosome formation. Surprisingly, substitution of the invariant loop 1 nucleotides with a GAGA tetraloop had no effect on U5 activity. Furthermore, U5 snRNPs reconstituted from an RNA formed by annealing the 5' and 3' halves of the U5 snRNA, which lacked all loop 1 nucleotides, complemented both steps of splicing. Thus, in contrast to yeast, loop 1 of the human U5 snRNA is dispensable for both steps of splicing in HeLa nuclear extracts. This suggests that its function can be compensated for in vitro by other spliceosomal components: for example, by proteins associated with the U5 snRNP. Consistent with this idea, immunoprecipitation studies indicated that several functionally important U5 proteins associate stably with U5 snRNPs containing a GAGA loop 1 substitution.

Animals↗

PubMed2001

Reciprocal activation by cyclin-dependent kinases 2 and 7 is directed by substrate specificity determinants outside the T loop.

Cyclin-dependent kinase 7 (CDK7) is the catalytic subunit of the metazoan CDK-activating kinase (CAK), which activates CDKs, such as CDC2 and CDK2, through phosphorylation of a conserved threonine residue in the T loop. Full activation of CDK7 requires association with a positive regulatory subunit, cyclin H, and phosphorylation of a conserved threonine residue at position 170 in its own T loop. We show that threonine-170 of CDK7 is phosphorylated in vitro by its targets, CDC2 and CDK2, which also phosphorylate serine-164 in the CDK7 T loop, a site that perfectly matches their consensus phosphorylation site. In contrast, neither CDK4 nor CDK7 itself can phosphorylate the CDK7 T loop in vitro. The ability of CDC2 or CDK2 and CDK7 to phosphorylate each other but not themselves implies that each kinase can discriminate among closely related sequences and can recognize a substrate site that diverges from its usual preferred site. To understand the basis for this paradoxical substrate specificity, we constructed a chimeric CDK with the T loop of CDK7 grafted onto the body of CDK2. Surprisingly, the hybrid enzyme, CDK2-7, was efficiently activated in cyclin A-dependent fashion by CDK7 but not at all by CDK2. CDK2-7, moreover, phosphorylated wild-type CDK7 but not CDK2. Our results suggest that the primary amino acid sequence of the T loop plays only a minor role, if any, in determining the specificity of cyclin-dependent CAKs for their CDK substrates and that protein-protein interactions involving sequences outside the T loop can influence substrate specificity both positively and negatively.

Amino Acid Motifs↗

PubMed2002

The histone 3'-terminal stem-loop-binding protein enhances translation through a functional and physical interaction with eukaryotic initiation factor 4G (eIF4G) and eIF3.

Metazoan cell cycle-regulated histone mRNAs are unique cellular mRNAs in that they terminate in a highly conserved stem-loop structure instead of a poly(A) tail. Not only is the stem-loop structure necessary for 3'-end formation but it regulates the stability and translational efficiency of histone mRNAs. The histone stem-loop structure is recognized by the stem-loop-binding protein (SLBP), which is required for the regulation of mRNA processing and turnover. In this study, we show that SLBP is required for the translation of mRNAs containing the histone stem-loop structure. Moreover, we show that the translation of mRNAs ending in the histone stem-loop is stimulated in Saccharomyces cerevisiae cells expressing mammalian SLBP. The translational function of SLBP genetically required eukaryotic initiation factor 4E (eIF4E), eIF4G, and eIF3, and expressed SLBP coisolated with S. cerevisiae initiation factor complexes that bound the 5' cap in a manner dependent on eIF4G and eIF3. Furthermore, eIF4G coimmunoprecipitated with endogenous SLBP in mammalian cell extracts and recombinant SLBP and eIF4G coisolated. These data indicate that SLBP stimulates the translation of histone mRNAs through a functional interaction with both the mRNA stem-loop and the 5' cap that is mediated by eIF4G and eIF3.

Cell Line↗

PubMedDate not supplied

A proposal for the conformation of loop E in Escherichia coli 5S rRNA.

A proposal is advanced for the conformation of the loop E region of prokaryotic 5S rRNAs based on spectroscopic data obtained from pAD3 RNA, a construct that includes helix IV, helix V, and loops D and E from Escherichia coli 5S rRNA. Even though loop E juxtaposes bases that cannot form Watson-Crick base pairs, it resembles an A-form double helix; its nucleotides relate to each other spectroscopically in a helix-like way and are in the anti conformation. The ends of loop E, which is palindromic, have the same conformation. Working in from either end towards the center of the loop, a closing GC is followed by a side-by-side GA and then by a reversed Hoogsteen AU, a pattern resembling that found at one end of eukaryotic loop E. The center of the loop consists of three nucleotide pairs, which appear to be an asymmetric GG pair, a Watson-Crick-like AG, and a GU stabilized by a single hydrogen bond.

Base Sequence↗

PubMed1990

Loop diuretic and anion modification of NEM-induced K transport in human red blood cells.

The thioalkylating agent N-ethylmaleimide (NEM) causes ouabain-insensitive K loss from human red blood cells. This K loss is inhibited when intracellular Cl is replaced by another permeant anion or when loop diuretics are placed in the incubation medium after NEM exposure. In this report, we have tested the possibility that Cl replacement or loop diuretics not only influence the transport of K induced by NEM but also the interaction of NEM with its target sulfhydryl group. This possibility was examined by replacing intracellular Cl or exposing the cells to loop diuretics before NEM exposure, then measuring K loss in a Cl medium free of loop diuretics. We found that such pretreatment with either Cl substitution or loop diuretics stimulated, rather than inhibited, NEM-induced K loss. This enhancement was not additive in that the increase in K loss induced by anion substitution was not increased further when loop diuretics were also present. These data suggest that anion substitution and loop diuretics enhance the interaction of NEM with its cellular target but inhibit the K loss induced by NEM.

Anions↗

PubMed1980

Local disorganization of interdigestive migrating complex by perfusion of a Thiry-Vella loop.

In dogs, a 50-cm Thiry-Vella loop was perfused with different glucose solutions (10-60%) and the effect on the interdigestive migrating myoelectric complex was studied. The perfusions did not disrupt the interdigestive pattern outside the loop, but produced a progressive "fall-out" of phase III, related to the concentration of the glucose solution. Quantitative analysis of the spike activity in the loop showed that the interdigestive pattern was partially disrupted by the 10% glucose solutions and that the 50 and 60% glucose perfusions induced a typical fed pattern characterized by short periods of spike activity alternating with short periods of quiescence. It was concluded that 1) perfusion of a Thiry-Vella loop with glucose solutions changes the myoelectrical activity of the loop from an interdigestive to a digestive pattern without interfering with the migrating myopelectric complex outside the loop; and 2) this local disorganization must be mediated by factors interfering with the effector mechanism in the loop.

Action Potentials↗

PubMedDate not supplied

Phylogenetic assessment of the mitochondrial DNA displacement loop haplotype in Japanese patients with Leber's hereditary optic neuropathy harboring the mitochondrial DNA G11778A mutation.

To investigate the anthropological background and the association of mitochondrial DNA (mtDNA) haplotype with the disease phenotype, the nucleotide sequence in the hypervariable segment of the displacement loop (D-loop) region of mtDNA was determined in Japanese patients with Leber's hereditary optic neuropathy (LHON) harboring the G11778A mutation. Genetic polymorphism of mtDNA was examined in 36 unrelated Japanese LHON patients who presented with bilateral optic nerve disease and had the mtDNA G11778A mutation. DNA was extracted from the peripheral blood after having obtained informed consent. The nucleotide sequence of the D-loop region (np 16,002-16,490) was directly determined. The intergenic deletion of the COII/tRNA(Lys) gene of mtDNA was also examined. From the data set of nucleotide alignments, the phylogeny of the mtDNA sequence and phenotypic diversity within the examined population were evaluated. One-base polymorphism was present at 37 different sites. The estimated value of nucleotide diversity was 0.69%. D-loop sequences were classified into 13 monophyletic clusters (CA to CM). There was not any definite ancestral haplotype of the D-loop sequence in the examined LHON population. Thus, the mutational event of G11778A appears to be independent of the evolutionary course in the D-loop haplotype. Patients with a CD plus CH cluster had a significantly older age at onset (p = 0.006), and had a family history being significantly lower as compared with patients with other clusters (p = 0.05). The mtDNA D-loop haplotype characterized by the presence of T16362C or C16290T, lacking G16129A and G16390A, may be a risk for older age at onset and other unusual clinical features in Japanese LHON patients with the G11778A mutation.

Base Sequence↗

PubMed1988

Scanning electron microscopic study of the capillary loops in the dermal papillae. Skin of the hand of the Japanese monkey (Macaca fuscata).

The microvasculature of the skin of the hand of Japanese monkeys was examined by means of scanning electron microscopy of corrosion casts. The vasculature of all areas of the skin of the hand was examined and divided into three structures excluding the nail bed: (1) In the ball of the finger, the typical structure of the capillary loops was studied. Capillary loops were formed out of not just one capillary vessel, but two or three vessels. Each capillary vessel arose and divided into several branches at the papilla, and they became descending limbs. After the loop passed a hairpin turn, the descending limbs were 1.5 times larger than the ascending limbs in the intrapapillary portion, and they became extrapapillary venules. The descending limbs connected with the postcapillary venules in the postpapillary portion and with the horizontal network. The postcapillary venules fused with each other (1-5 loops) to form the primary and secondary venous arcades. (2) In the thenar eminence, the capillary loops were a little lower, and their grooves were wider than in the ball of the finger. The characteristic structure in this area was the interpapillar capillary network. (3) In the lateral side of the finger, the number of capillary loops formed by the arterial capillary network of the subepidermal layer was smaller. The capillary loops here had the lowest height and a simple structure.

Animals↗

PubMed2005

The functional significance of the autolysis loop in protein C and activated protein C.

The autolysis loop of activated protein C (APC) is five residues longer than the autolysis loop of other vitamin K-dependent coagulation proteases. To investigate the role of this loop in the zymogenic and anticoagulant properties of the molecule, a protein C mutant was constructed in which the autolysis loop of the protein was replaced with the corresponding loop of factor X. The protein C mutant was activated by thrombin with approximately 5-fold higher rate in the presence of Ca2+. Both kinetics and direct binding studies revealed that the Ca2+ affinity of the mutant has been impaired approximately 3-fold. The result of a factor Va degradation assay revealed that the anticoagulant function of the mutant has been improved 4-5-fold in the absence but not in the presence of protein S. The improvement was due to a better recognition of both the P1-Arg506 and P1-Arg306 cleavage sites by the mutant protease. However, the plasma half-life of the mutant was markedly shortened due to faster inactivation by plasma serpins. These results suggest that the autolysis loop of protein C is critical for the Ca(2+)-dependence of activation by thrombin. Moreover, a longer autolysis loop in APC is not optimal for interaction with factor Va in the absence of protein S, but it contributes to the lack of serpin reactivity and longer half-life of the protease in plasma.

Anticoagulants↗

PubMed2005

Full cyclic coordinate descent: solving the protein loop closure problem in Calpha space.

BACKGROUND: Various forms of the so-called loop closure problem are crucial to protein structure prediction methods. Given an N- and a C-terminal end, the problem consists of finding a suitable segment of a certain length that bridges the ends seamlessly. In homology modelling, the problem arises in predicting loop regions. In de novo protein structure prediction, the problem is encountered when implementing local moves for Markov Chain Monte Carlo simulations. Most loop closure algorithms keep the bond angles fixed or semi-fixed, and only vary the dihedral angles. This is appropriate for a full-atom protein backbone, since the bond angles can be considered as fixed, while the (phi, psi) dihedral angles are variable. However, many de novo structure prediction methods use protein models that only consist of Calpha atoms, or otherwise do not make use of all backbone atoms. These methods require a method that alters both bond and dihedral angles, since the pseudo bond angle between three consecutive Calpha atoms also varies considerably. RESULTS: Here we present a method that solves the loop closure problem for Calpha only protein models. We developed a variant of Cyclic Coordinate Descent (CCD), an inverse kinematics method from the field of robotics, which was recently applied to the loop closure problem. Since the method alters both bond and dihedral angles, which is equivalent to applying a full rotation matrix, we call our method Full CCD (FCDD). FCCD replaces CCD's vector-based optimization of a rotation around an axis with a singular value decomposition-based optimization of a general rotation matrix. The method is easy to implement and numerically stable. CONCLUSION: We tested the method's performance on sets of random protein Calpha segments between 5 and 30 amino acids long, and a number of loops of length 4, 8 and 12. FCCD is fast, has a high success rate and readily generates conformations close to those of real loops. The presence of constraints on the angles only has a small effect on the performance. A reference implementation of FCCD in Python is available as supplementary information.

Algorithms↗

PubMed2006

Modification of the mycobacteriophage Ms6 attP core allows the integration of multiple vectors into different tRNAala T-loops in slow- and fast-growing mycobacteria.

BACKGROUND: Mycobacteriophage Ms6 integrates into Mycobacterium smegmatis and M. bovis BCG chromosome at the 3' end of tRNAala genes. Homologous recombination occurs between the phage attP core and the attB site located in the T-loop. Integration-proficient vectors derived from Ms6 are useful genetic tools, but their insertion sites in the BCG chromosome remain poorly defined. The primary objective of this study was to identify Ms6 target genes in M. smegmatis and BCG. We then aimed to modify the attP site in Ms6-derived vectors, to switch integration to other tRNAala loci. This provided the basis for the development of recombinant M. bovis BCG strains expressing several reporter genes inserted into different tRNAala genes. RESULTS: The three tRNAala genes are highly conserved in M. smegmatis and BCG. However, in the T-loop of tRNAalaU and tRNAalaV containing the attB site, a single base difference was observed between the two species. We observed that the tRNAalaU gene was the only site into which Ms6-derived integration-proficient vectors integrated in M. smegmatis, whereas in BCG, the tRNAalaV gene was used as the target. No integration occurred in the BCG tRNAalaU T-loop, despite a difference of only one base from the 26-base Ms6 attP core. We mutated the attP core to give a perfect match with the other tRNAala T-loops from M. smegmatis and BCG. Modification of the seven-base T-loop decreased integration efficiency, identifying this site as a possible site of strand exchange. Finally, two Ms6 vectors were constructed to integrate two reporter genes into the tRNAalaU and tRNAalaV T-loops of the same BCG chromosome. CONCLUSION: Small changes in the 7 bp T-loop attP site of Ms6 made it possible to use another attB site, albeit with a lower integration efficiency. These molecular studies on BCG tRNAala genes made it possible to create valuable tools for the site-directed insertion of several genes in the same BCG strain. These tools will be useful for the development of novel multivalent vaccines and genetic studies.

Attachment Sites, Microbiological↗

PubMed2007

Mutations in the TPsiC loop of E. coli tRNALys,3 have varied effects on in trans complementation of HIV-1 replication.

BACKGROUND: Human immunodeficiency virus (HIV-1) exclusively selects and utilizes tRNALys,3 as the primer for initiation of reverse transcription. Several elements within the TPsiC stem loop of tRNALys,3 are postulated to be important for selection and use in reverse transcription. The post-transcriptional modification at nucleotide 58 could play a role during plus-strand synthesis to stop reverse transcriptase from re-copying the tRNA primer. Nucleotides 53 and 54 within the TPsiC stem loop of the tRNA have been shown to be important to form the complex between tRNA and the HIV-1 viral genome during initiation of reverse transcription. RESULTS: To further delineate the features of the TPsiC stem loop of tRNALys,3 in reverse transcription, we have developed a complementation system in which E. coli tRNALys,3 is provided in trans to an HIV-1 genome in which the PBS is complementary to this tRNA. Successful selection and use of E. coli tRNALys,3 results in the production of infectious virus. We have used this single round infectious system to ascertain the effects that different mutants in the TPsiC stem loop of tRNALys,3 have on complementation. Mutants were designed within the TPsiC loop (nucleotide 58) and within the stem and loop of the TPsiC loop (nucleotides 53 and 54). Analysis of the expression of E. coli tRNALys,3 mutants revealed differences in the capacity for aminoacylation, which is an indication of intracellular stability of the tRNA. Alteration of nucleotide 58 from A to U (A58U), T54G and TG5453CC all resulted in tRNALys,3 that was aminoacylated when expressed in cells, while a T54C mutation resulted in a tRNALys,3 that was not aminoacylated. Both the A58U and T54G mutated tRNALys,3 complemented HIV-1 replication similar to wild type E. coli tRNALys,3. In contrast, the TG5453CC tRNALys,3 mutant did not complement replication. CONCLUSION: The results demonstrate that post-transcriptional modification of nucleotide 58 in tRNALys,3 is not essential for HIV-1 reverse transcription. In contrast, nucleotides 53 and 54 of tRNALys,3 are important for aminoacylation and selection and use of the tRNALys,3 in reverse transcription.

Base Sequence↗

PubMed2026

UnionLoops: a workflow for calling chromatin loops across related Hi-C datasets with improved specificity, precision, and sensitivity.

Chromatin loop calling from chromatin interaction data often exhibits substantial variability across related samples. We present UnionLoops, a computational workflow for chromatin loop calling across multiple related samples. UnionLoops integrates information across datasets to determine positions and dataset-specificity of looping interactions. It constructs a unified candidate loop set, applies consistent filtering and aggregation, and evaluates loop support across samples. We demonstrate that UnionLoops increases sensitivity for detecting shared chromatin loops, reduces spurious sample-specific calls, and improves concordance with independent genomic features, including CTCF and cohesin occupancy. UnionLoops enables improved biological interpretation of chromatin loop organization and dynamics across related conditions.

Chromatin↗

PubMed2005

Analysis of proteome bound to D-loop region of mitochondrial DNA by DNA-linked affinity chromatography and reverse-phase liquid chromatography/tandem mass spectrometry.

Mitochondrial dysfunction has been suggested as a causal factor for insulin resistance and diabetes. Previously we have shown a decrease of mitochondrial DNA (mtDNA) content in tissues of diabetic patients. The mitochondrial proteins, which regulate the mitochondrial biogensis, including transcription and replication of mtDNA, are encoded by nuclear DNA. Despite the potential function of the proteins bound to the D-loop region of mtDNA in regulating mtDNA transcription/replication, only a few proteins are known to bind the D-loop region of mtDNA. The functional association of these known proteins with insulin resistance is weak. In this study, we applied proteomic analysis to identify a group of proteins (proteome) that physically bind to D-loop DNA of mtDNA. We amplified D-loop DNA (1.1 kb) by PCR and conjugated the PCR fragments to CNBr-activated sepharose. Mitochondria fractions were isolated by both differential centrifugation and Optiprep-gradient ultracentrifugation. The D-loop DNA binding proteome fractions were enriched via this affinity chromatography and analyzed by SDS-PAGE. The proteins on the gel were transferred onto PVDF membrane and the peptide sequences of each band were subsequently analyzed by capillary reverse-phase liquid chromatography/tandem mass spectrometry (RPLC/MS/MS). We identified many D-loop DNA binding proteins, including mitochondrial transcription factor A (mtTFA, Tfam) and mitochondrial single-stranded DNA binding protein (mtSSBP) which were known to bind to mtDNA. We also report the possibility of novel D-loop binding proteins such as histone family proteins and high-mobility group proteins.

Amino Acid Sequence↗

PubMed2005

Pulsatile tinnitus and the intrameatal vascular loop: why do we not hear our carotids?

OBJECTIVE: Pulsatile tinnitus is characterized by hearing the heart beat or respiration in one or both ears. In 15% of patients with pulsatile tinnitus, no cause can be found. Other investigators have suggested that a vascular loop entering the internal auditory meatus can be another cause of arterial, pulse synchronous tinnitus. If so, we should constantly hear the arterial pulsations of the carotid arteries passing through the petrous bone. METHODS: Using magnetic resonance imaging, 17 patients with unilateral pulsatile tinnitus and 46 with non-pulsatile tinnitus were analyzed for the presence of a vascular loop entering into the internal acoustic meatus. Four temporal bones were sectioned to find structural differences between the internal acoustic meatus and the pericarotid area. Four patients with intrameatal vascular loops and ipsilateral pulsatile tinnitus underwent surgery by Teflon interpositioning between the loop and the cochlea. RESULTS: In unilateral pulsatile tinnitus, a statistically highly significant amount of intrameatal vascular loops was noted in comparison to non-pulsatile tinnitus. A well-developed pericarotid venous plexus was found histologically. Three of the four patients who underwent surgery were initially tinnitus free, but pulsations recurred after 3 months in one patient. CONCLUSION: Vascular loops in the internal auditory canal may generate pulsatile tinnitus. It may be treated by placing Teflon between the cochlea and the intrameatal vascular loop. One then does not hear the pulsation of the carotids due to a dampening effect of a pericarotid venous plexus.

Adolescent↗

PubMed2000

The large intracytoplasmic loop of the glucose transporter GLUT2 is involved in glucose signaling in hepatic cells.

The hypothesis that the glucose transporter GLUT2 can function as a protein mediating transcriptional glucose signaling was addressed. To divert the putative interacting proteins from a glucose signaling pathway, two intracytoplasmic domains of GLUT2, the C terminus and the large loop located between transmembrane domains 6 and 7, were transfected into mhAT3F hepatoma cells. Glucose-induced accumulation of two hepatic gene mRNAs (GLUT2 and L-pyruvate kinase) was specifically inhibited in cells transfected with the GLUT2 loop and not with the GLUT2 C terminus. The dual effects of glucose were dissociated in cells expressing the GLUT2 loop; in fact a normal glucose metabolism into glycogen occurred concomitantly with the inhibition of the glucose-induced transcription. This inhibition by the GLUT2 loop could be due to competitive binding of a protein that normally interacts with endogenous GLUT2. In addition, the GLUT2 loop, tagged with green fluorescent protein (GFP), was located within the nucleus, whereas the GFP and GFP-GLUT2 C-terminal proteins remained in the cytoplasm. In living cells, a fraction (50%) of the expressed GFP-GLUT2 loop translocated rapidly from the cytoplasm to the nucleus in response to high glucose concentration and conversely in the absence of glucose. We conclude that, via protein interactions with its large loop, GLUT2 may transduce a glucose signal from the plasma membrane to the nucleus.

Animals↗

PubMed2004

Open-loop feedback increases physical activity of youth.

PURPOSE: The number of youth that meet activity guidelines is decreasing and easy access to reinforcing sedentary behaviors competes with increasing physical activity. In the laboratory, open-loop feedback that used pedometer activity counts to gain access to sedentary alternatives doubled physical activity. This study evaluated the influence of open-loop feedback and reinforcement on physical activity and television (TV) time in a small clinical trial. METHODS: Children (8-12 yr old) were randomized to an open-loop feedback plus reinforcement intervention (N = 11) or no feedback, no reinforcement control (N = 7). Subjects wore an accelerometer for 6 wk and attended meetings to download the accelerometer. Accumulating physical activity counts gave subjects in the open-loop group access to TV time, controlled by a TV Allowance device, with 400 counts = 1 h of TV. The control group had no feedback for activity and free access to TV. RESULTS: The open-loop group had a 24% increase in physical activity, which was greater (P = 0.02) than the control group. TV time of the open-loop group was reduced by 18% or 20 min x d(-1) whereas the control group increased by 13 min x d(-1), but these were not significant changes. The change in time spent watching television was directly related to the change in BMI z-score (r = 0.69, P = 0.002). CONCLUSION: Open-loop feedback increases physical activity in children, thus helping children to achieve physical activity recommendations. Reductions in TV watching may reduce or minimize gains in body weight.

Biofeedback, Psychology↗