Search PubMed⌕ Search

Biomedical subjects

M G Lee

Publications and source records attributed to M G Lee.

At least 19 recordsLinked to original sources

Mitochondrial dysfunction by gamma-irradiation accompanies the induction of cytochrome P450 2E1 (CYP2E1) in rat liver.

Multiple biological effects are induced by ionizing radiation through dysfunction of cellular organelles, direct interaction with nucleic acids and production of free radical species. The expression of cytochrome P450s was assessed in the livers of 60Co gamma-irradiated rats. Three gray (G) of gamma-irradiation caused CYP2E1 induction with a 3.6-fold increase in the mRNA at 24 h, whereas the expression of CYP1A2 and CYP3A was not changed. Pharmacokinetics of chlorzoxazone, a specific substrate of CYP2E1, was studied in 3 G-irradiated rats. The area under the plasma concentration-time curve from time zero to infinity of 6-hydroxychlorzoxazone and the amount of 6-hydroxychlorzoxazone excreted in 8 h urine were both significantly greater than those in control rats. Hepatic CYP2E1 was not induced in rats exposed to 0.5-1 G of gamma-rays. Rats irradiated at 6-9 G accumulated doses of gamma-rays exhibited smaller increases in the mRNA due to liver injury than those irradiated at a single dose of 3 G gamma-rays. The plasma glucose and insulin levels were not altered in rats with 3 G of gamma-irradiation. As the exposure level of gamma-irradiation increased, the activity of hepatic aconitase, a key enzyme in energy metabolism in mitochondria, was 30-90% decreased. The amount of mitochondrial DNA per gram of wet liver was 50% decreased in rats exposed to 3 G of gamma-rays. These results demonstrated that gamma-ray irradiation at the exposure level inducing organelle dysfunction induced CYP2E1 in the liver, which might be associated with mitochondrial damage, but not with alterations in glucose or insulin levels.

Aconitate Hydratase↗

Aberrant CFTR-dependent HCO3- transport in mutations associated with cystic fibrosis.

Cystic fibrosis (CF) is a disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR). Initially, Cl- conductance in the sweat duct was discovered to be impaired in CF, a finding that has been extended to all CFTR-expressing cells. Subsequent cloning of the gene showed that CFTR functions as a cyclic-AMP-regulated Cl- channel; and some CF-causing mutations inhibit CFTR Cl- channel activity. The identification of additional CF-causing mutants with normal Cl- channel activity indicates, however, that other CFTR-dependent processes contribute to the disease. Indeed, CFTR regulates other transporters, including Cl(-)-coupled HCO3- transport. Alkaline fluids are secreted by normal tissues, whereas acidic fluids are secreted by mutant CFTR-expressing tissues, indicating the importance of this activity. HCO3- and pH affect mucin viscosity and bacterial binding. We have examined Cl(-)-coupled HCO3- transport by CFTR mutants that retain substantial or normal Cl- channel activity. Here we show that mutants reported to be associated with CF with pancreatic insufficiency do not support HCO3- transport, and those associated with pancreatic sufficiency show reduced HCO3- transport. Our findings demonstrate the importance of HCO3- transport in the function of secretory epithelia and in CF.

Bicarbonates↗

Regulatory interaction between the cystic fibrosis transmembrane conductance regulator and HCO3- salvage mechanisms in model systems and the mouse pancreatic duct.

The pancreatic duct expresses cystic fibrosis transmembrane conductance regulator (CFTR) and HCO3- secretory and salvage mechanisms in the luminal membrane. Although CFTR plays a prominent role in HCO3- secretion, the role of CFTR in HCO3- salvage is not known. In the present work, we used molecular, biochemical, and functional approaches to study the regulatory interaction between CFTR and the HCO3- salvage mechanism Na+/H+ exchanger isoform 3 (NHE3) in heterologous expression systems and in the native pancreatic duct. We found that CFTR regulates NHE3 activity by both acute and chronic mechanisms. In the pancreatic duct, CFTR increases expression of NHE3 in the luminal membrane. Thus, luminal expression of NHE3 was reduced by 53% in ducts of homozygote DeltaF508 mice. Accordingly, luminal Na+-dependent and HOE694- sensitive recovery from an acid load was reduced by 60% in ducts of DeltaF508 mice. CFTR and NHE3 were co-immunoprecipitated from PS120 cells expressing both proteins and the pancreatic duct of wild type mice but not from PS120 cells lacking CFTR or the pancreas of DeltaF508 mice. The interaction between CFTR and NHE3 required the COOH-terminal PDZ binding motif of CFTR, and mutant CFTR proteins lacking the C terminus were not co-immunoprecipitated with NHE3. Furthermore, when expressed in PS120 cells, wild type CFTR, but not CFTR mutants lacking the C-terminal PDZ binding motif, augmented cAMP-dependent inhibition of NHE3 activity by 31%. These findings reveal that CFTR controls overall HCO3- homeostasis by regulating both pancreatic ductal HCO3- secretory and salvage mechanisms.

Animals↗

HCO3- salvage mechanisms in the submandibular gland acinar and duct cells.

In the present work, we characterized H(+) and HCO3- transport mechanisms in the submandibular salivary gland (SMG) ducts of wild type, NHE2-/-, NHE3-/-, and NHE2-/-;NHE3-/- double knock-out mice. The bulk of recovery from an acid load across the luminal membrane (LM) of the duct was mediated by a Na(+)-dependent HOE and ethyl-isopropyl-amiloride (EIPA)-inhibitable and 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS)-insensitive mechanism. HCO3- increased the rate of luminal Na(+)-dependent pH(i) recovery but did not change inhibition by HOE and EIPA or the insensitivity to DIDS. Despite expression of NHE2 and NHE3 in the LM of the duct, the same activity was observed in ducts from wild type and all mutant mice. Measurements of Na(+)-dependent OH(-) and/or HCO3- cotransport (NBC) activities in SMG acinar and duct cells showed separate DIDS-sensitive/EIPA-insensitive and DIDS-insensitive/EIPA-sensitive NBC activities in both cell types. Functional and immunocytochemical localization of these activities in the perfused duct indicated that pNBC1 probably mediates the DIDS-sensitive/EIPA-insensitive transport in the basolateral membrane, and splice variants of NBC3 probably mediate the DIDS-insensitive/EIPA-sensitive NBC activity in the LM of duct and acinar cells. Notably, the acinar cell NBC3 variants transported HCO3- but not OH(-). By contrast, duct cell NBC3 transported both OH(-) and HCO3-. Accordingly, reverse transcription-polymerase chain reaction analysis revealed that both cell types expressed mRNA for pNBC1. However, the acini expressed mRNA for the NBC3 splice variants NBCn1C and NBCn1D, whereas the ducts expressed mRNA for NCBn1B. Based on these findings we propose that the luminal NBCs in the HCO3- secreting SMG acinar and duct cells function as HCO3- salvage mechanisms at the resting state. These studies emphasize the complexity but also begin to clarify the mechanism of HCO3- homeostasis in secretory epithelia.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

Prevention of c-Jun/activator protein-1 activation and microsomal epoxide hydrolase induction in the rat liver by cysteine during protein-calorie malnutrition.

Protein-calorie malnutrition (PCM), a major global health problem, arises during protein and/or energy deficit due to disease and nutritional inadequacy. To date, cellular adaptive responses and gene expression associated with PCM remain poorly understood. In view of the primary role of the liver in energy conversion, the present study was designed to investigate changes in hepatic morphology and molecular alterations during PCM. PCM caused marked decreases in the cytoplasmic eosinophilic content and nuclear shrinkage in the hepatocytes with a decrease in glutathione content. The nuclear activator protein-1 (AP-1) complex was activated in the liver of PCM rats. AP-1-binding activity of nuclear extracts produced from PCM rats was reduced by the presence of anti-c-Jun antibody. Microsomal epoxide hydrolase (mEH), a phase II detoxifying enzyme, was 4-fold induced, with a 20-fold increase in the mRNA level during PCM. In contrast to the PCM-induced changes in hepatic morphology, PCM rats supplemented with cysteine showed an increase in the GSH level and well-preserved hepatic structures with mild fat degeneration. Cysteine supplementation inhibited the activation of AP-1 and the induction of mEH in PCM rats. These results provided evidence: (i) that PCM alters liver morphology with a decrease in the glutathione level; (ii) that cysteine may serve as a key element responsible for preserving hepatic morphology and maintaining the glutathione level; and (iii) that cysteine was active in preventing the activation of AP-1 and mEH induction in the liver during PCM.

Animals↗

Characteristics of Helicobacter pylori infection in Jamaican adults with gastrointestinal symptoms.

Helicobacter pylori infection is common in Jamaica. Describing its epidemiology in a population-based study depends largely on serology, but serologic assays have not been validated in this population. To address this issue, we examined the presence of H. pylori infection in 30 sequential adult patients with gastroduodenal symptoms by three biopsy-based methods (rapid urease test, histology, and culture) as well as by one research and two commercial enzyme-linked immunosorbent assays (ELISAs). A patient was considered H. pylori positive if the organism was detected by at least one biopsy-based method. Eighteen (60%) of the 30 patients were H. pylori positive by these criteria, whereas 21 (70%) were seropositive for H. pylori immunoglobulin G by our research ELISA. The presence of H. pylori infection in patients with gastric cancer and those with chronic gastritis was missed by biopsy-based methods but was detected by serologic assays. This observation indicates that serologic assays may be better suited for the detection of this infection in a population in which H. pylori-associated pathology is prevalent. The performance of our research ELISA in detecting biopsy-based H. pylori-positive cases was excellent, with a sensitivity and specificity of 100% and 75%, respectively. Molecular genotyping of the isolates revealed that the predominant H. pylori genotypes in this cohort of Jamaicans were cagA(+) vacA slb-m1, and iceA2. The validated serologic assay enables us to interpret epidemiologic data from population-based studies in Jamaica by comparison to those from other populations.

Adult↗

Costunolide induces apoptosis by ROS-mediated mitochondrial permeability transition and cytochrome C release.

Costunolide is an active compound isolated from the root of Saussurea lappa Clarks, a Chinese medicinal herb, and is considered a therapeutic candidate for various types of cancers. Nevertheless, the pharmacological pathways of costunolide are still unknown. In this study, we investigate the effects of costunolide on the induction of apoptosis in HL-60 human leukemia cells and its putative pathways of action. Using apoptosis analysis, measurement of reactive oxygen species (ROS), and assessment of mitochondrial membrane potentials, we show that costunolide is a potent inducer of apoptosis, and facilitates its activity via ROS generation, thereby inducing mitochondrial permeability transition (MPT) and cytochrome c release to the cytosol. ROS production, mitochondrial alteration, and subsequent apoptotic cell death in costunolide-treated cells were blocked by the antioxidant N-acetylcystein (NAC). Cyclosporin A, a permeability transition inhibitor, also inhibited mitochondrial permeability transition and apoptosis. Our data indicate that costunolide induces the ROS-mediated mitochondrial permeability transition and resultant cytochrome c release. This is the first report on the mechanism of the anticancer effect of costunolide.

Animals↗

Bioequivalence of two aceclofenac tablet formulations after a single oral dose to healthy male Korean volunteers.

A bioequivalence study of aceclofenac tablets (test formulation: Dong-A, reference formulation: Airtal) was conducted in 16 healthy male Korean volunteers who received each medicine at a dose of 100 mg in a 2 x 2 crossover study. There was a one-week washout period between the doses. Plasma concentrations of aceclofenac were monitored by high-performance liquid chromatography over a period of 24 hours after the administration. AUCinf (the area under the plasma concentration-time curve from time zero to time infinity) was calculated by the linear-log trapezoidal method. Cmax (maximum plasma drug concentration) and tmax (time to reach Cmax) were compiled from the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed AUCinf and Cmax, and non-transformed tmax. There were no significant differences between the medications in AUCinf and Cmax. The point estimates and 90% confidence intervals for AUCinf (parametric) and Cmax (parametric) were 1.04 (0.93 to approximately 1.17) and 0.99 (0.91 to approximately 1.08), respectively, satisfying the bioequivalence criteria of the European Committee for Proprietary Medicinal Products and the US Food and Drug Administration Guidelines. The corresponding value for tmax was 0.75 (0.00 to approximately 1.00). Moreover, the modified Pitman-Morgan's adjusted F-test indicated that the bioavailabilities of aceclofenac in the 2 medications were comparable regarding intra- and interindividual variability. Therefore, these results indicate that the 2 medications of aceclofenac are bioequivalent and, thus, may be prescribed interchangeably.

Administration, Oral↗

Characterization of geranium (Pelargonium graveolens) chloroplast EF-Tu cDNA.

A geranium (Pelargonium graveolens) chloroplast translational elongation factor EF-Tu (tufA) cDNA was isolated. The geranium tufA cDNA is 1,584 bp long with 20 bp of 5' untranslated region (UTR) and 139 bp of 3' UTR. It encodes 474 amino acids including a putative chloroplast transit peptide of 65 amino acids. The deduced polypeptides of the geranium tufA cDNA contains four GTP binding sequences in its N-terminal region and two chloroplast EF-Tu signature regions in the C-terminal region. The predicted molecular weight of the mature geranium chloroplast EF-Tu protein was about 45,000 and its amino acid sequence identity with the chloroplast EF-Tu proteins of tobacco, pea, Arabidopsis, rice, and soybean ranges from 85% to 91%. The geranium tufA appears to exist as a single copy gene like Arabidopsis and rice, whereas other known dicot plants have more than one copy in their nuclear genomes.

Amino Acid Sequence↗

Intracellular calcium mobilization induces immediate early gene pip92 via Src and mitogen-activated protein kinase in immortalized hippocampal cells.

Regulation of intracellular calcium levels plays a central role in cell survival, proliferation, and differentiation. A cell-permeable, tumor-promoting thapsigargin elevates the intracellular calcium levels by inhibiting endoplasmic reticulum Ca(2+)-ATPase. The Src-tyrosine kinase family is involved in a broad range of cellular responses ranging from cell growth and cytoskeletal rearrangement to differentiation. The immediate early gene pip92 is induced in neuronal cell death as well as cell growth and differentiation. To resolve the molecular mechanism of cell growth by intracellular calcium mobilization, we have examined the effect of thapsigargin and subsequent intracellular calcium influx on pip92 expression in immortalized rat hippocampal H19-7 cells. An increase of intracellular calcium ion levels induced by thapsigargin stimulated the expression of pip92 in H19-7 cells. Transient transfection of the cells with kinase-inactive mitogen-activated protein kinase kinase (MEK) and Src kinase or pretreatment with the chemical MEK inhibitor PD98059 significantly inhibited pip92 expression induced by thapsigargin. When constitutively active v-Src or MEK was overexpressed, the transcriptional activity of the pip92 gene was markedly increased. Dominant inhibitory Raf-1 blocked the transcriptional activity of pip92 induced by thapsigargin. The transcription factor Elk1 is activated during thapsigargin-induced pip92 expression. Taken together, these results suggest that an increase of intracellular calcium ion levels by thapsigargin stimulates the pip92 expression via Raf-MEK-extracellular signal-regulated protein kinase- as well as Src kinase-dependent signaling pathways.

Animals↗

The effect of cysteine on the altered expression of class alpha and mu glutathione S-transferase genes in the rat liver during protein-calorie malnutrition.

Protein-calorie malnutrition (PCM) represents a global health problem. The breakdown rate of glutathione S-transferase (GST) subunits determines their differential contents during protein depletion. Hepatic GST expression and the underlying mechanistic basis were investigated in PCM rats. PCM caused no change in rGSTA1/2 subunit. In contrast, rGSTA3/5 subunit was 2.4-fold induced during PCM, while the levels for rGSTM1 and M2 subunits were 30% and 70% suppressed. Increased GSTA3/5 expression was significantly prevented by cysteine or methionine treatment, although such treatment failed to restore the rGSTM2 level. In contrast to differential GST protein expression, PCM caused a 5-10-fold increase in rGSTA2/A3/A5 and M1 mRNAs, whereas rGSTM2 mRNA was 70% decreased. The elevations in rGSTA2/A3/A5 and M1 mRNAs were completely abolished by cysteine or methionine treatment during PCM, although the rGSTM2 mRNA level was not restored. PCM induced oxidative stress in the liver, as evidenced by protein carbonylation. Antioxidant response element (ARE)-binding activity of nuclear extracts from PCM rats was increased, which was immunodepleted with anti-Nrf-1/2 antibodies. Activation of nuclear ARE-binding proteins was inhibited by cysteine. Data showed that hepatic GSTs were differentially expressed during PCM, that certain GST mRNAs were increased with the ARE activation, and that cysteine was active in preventing increases in GST mRNAs and ARE activation.

Animals↗

Crystal structure of Escherichia coli CyaY protein reveals a previously unidentified fold for the evolutionarily conserved frataxin family.

Friedreich ataxia is an autosomal recessive neurodegenerative disease caused by defects in the FRDA gene, which encodes a mitochondrial protein called frataxin. Frataxin is evolutionarily conserved, with homologs identified in mammals, worms, yeast, and bacteria. The CyaY proteins of gamma-purple bacteria are believed to be closely related to the ancestor of frataxin. In this study, we have determined the crystal structure of the CyaY protein from Escherichia coli at 1.4-A resolution. It reveals a protein fold consisting of a six-stranded antiparallel beta-sheet flanked on one side by two alpha-helices. This fold is likely to be shared by all members of the conserved frataxin family. This study also provides a framework for the interpretation of disease-associated mutations in frataxin and for understanding the possible functions of this protein family.

Amino Acid Sequence↗

Receptor-mediated endocytosis in the procyclic form of Trypanosoma brucei.

In Trypanosomatids, endocytosis and exocytosis occur exclusively at the flagellar pocket, a deep invagination of the plasma membrane where the flagellum extends from the cell. Both bloodstream and procyclic trypanosomes are capable of internalizing macromolecules. However, structures resembling coated vesicles were only identified in bloodstream form and not in procyclic form trypanosomes. Due to the apparent absence of coated vesicles in procyclics, the significance of receptor-mediated endocytosis in procyclic trypanosomes has been considered of minimal importance. We show that the flagellar pocket associated cysteine-rich acidic transmembrane protein (CRAM) may function as an high density lipoprotein receptor in the procyclic form trypanosome. Using anti-CRAM IgG we have characterized the process of CRAM-mediated endocytosis in procyclic form trypanosomes. The wild type procyclic trypanosome binds and internalizes anti-CRAM IgG but not the non-immune IgG in a saturable and time-dependent manner; the binding and uptake of (125)I-labeled anti-CRAM IgG are inhibited by excess unlabeled anti-CRAM IgG. Uptake and degradation of anti-CRAM IgG do not occur at 4 degrees C. At 28 degrees C, the internalized anti-CRAM IgG were efficiently degraded through a process that is inhibited by incubation at 4 degrees C and sensitive to the presence of chloroquine. The uptake and degradation of anti-CRAM IgG does not occur in the CRAM null mutant cell line. These results suggested that the uptake of anti-CRAM IgG in the wild type procyclics occurs via receptor-mediated endocytosis of the CRAM protein. Deletion of the cytoplasmic extension of CRAM drastically reduced the degradation but not the binding of anti-CRAM IgG. This result indicated that potential internalization signals may be present in the cytoplasmic extension of CRAM. This is the first time that the importance of receptor-mediated endocytosis in procyclic form trypanosomes has been demonstrated.

Amino Acid Sequence↗

Intestinal first-pass effect of bumetanide in rats.

The intestinal first-pass effect of bumetanide was investigated after intravenous and intraportal infusion, and intragastric and intraduodenal instillation of the drug to rats. The AUC(0-->8 h) values of bumetanide after intragastric and intraduodenal instillation of the drug, 10 and 20 mg/kg, were significantly smaller than AUC values after intraportal administration, suggesting that the gastrointestinal first-pass effect of bumetanide was considerable in rats. However, the AUC(0-->8 h) values of bumetanide between intragastric and intraduodenal instillation were comparable, suggesting that the gastric first-pass effect of bumetanide was almost negligible in rats. The AUC(0-->8 h) values of bumetanide after intraduodenal instillation were significantly smaller than AUC values after intraportal infusion at 10 (89.8 vs 569 microg min per ml) and 20 (304 vs 1230 microg min per ml) mg/kg, indicating that the first-pass organ(s) of bumetanide was intestine. The F values were 15.8 and 24.7% after intraduodenal instillation of bumetanide, 10 and 20 mg/kg, respectively. Approximately 76.1 and 76.5% of intraduodenally instilled bumetanide disappeared (as a result of absorption and first-pass effect) after 10 and 20 mg/kg, respectively. Therefore, it could be concluded that approximately 60. 3 and 51.8% of the oral dose of bumetanide disappeared by intestinal first-pass effect at 10 and 20 mg/kg, respectively.

Animals↗

A novel effect of rebamipide: generation of [Ca(2+)](i) oscillations through activation of CCK(1) receptors in rat pancreatic acinar cells.

The protective effect of 2-(4-chlorobenzoylamino)-3-[2(1H)-quinolinon-4-yl]-propionic acid (rebamipide) on gastric mucosa is well established. Here we demonstrate that rebamipide acts on pancreatic acinar cells to generate oscillations of intracellular Ca(2+) concentration ([Ca(2+)](i)) through the activation of cholecystokinin subtype 1 (CCK(1)) receptors. At concentrations higher than 5 microM, rebamipide induced [Ca(2+)](i) oscillations in individual fura-2-loaded pancreatic acinar cells. The frequency of oscillations increased with increasing concentrations of rebamipide, while the latency between stimulation of cells and initiation of [Ca(2+)](i) oscillations decreased with increasing concentration. The [Ca(2+)](i) oscillations evoked by rebamipide were inhibited by the CCK(1) receptor antagonist L-364,718 but not by atropine or the CCK(2) receptor antagonist L-365,260 indicating that rebamipide is a nonpeptide CCK(1) receptor agonist.

Alanine↗

Pharmacokinetics, skin absorption, stability, blood partition, and protein binding of AS 2-006A, a new wound healing agent.

After intravenous administration of AS 2-006A, 20, 50, and 90 mg/kg, to rats, the pharmacokinetic parameters, terminal half-life (69.8-86. 6 min), mean residence time (56.2-75.2 min), apparent volume of distribution at steady state (809-1040 mL/kg), and total body clearance (11.4-11.9 mL/min/kg), were dose-independent. After topical application of 0.5 or 1% AS 2-006A ointment, 300 mg, to abraded rat skin, the absorbed amounts were dose (0.5 and 1%) and time (30, 60, 120, 240, 360 and 480 min)-independent; the value was approximately 20%. The tissue-to-plasma ratios of AS 2-006A were greater than unity in all rat tissues studied, except in the muscle and large intestine. AS 2-006A was stable for up to 24 h incubation in rat plasma, and human plasma and urine; however, it seemed not to be stable in rat urine; the disappearance rate constant was 0.0218/h. AS 2-006A reached equilibrium fast between plasma and blood cells, and the equilibrium plasma/blood cells partition ratios were independent of the initial rabbit blood concentrations of AS 2-006A, 10, 20, and 50 microg/mL; the mean values were in the range of 2.38-2.75 for three rabbit blood. The protein binding of AS 2-006A to rat plasma was high, as the drug was under detection limit in the filtrate at the plasma concentrations of the drug, ranging from 7.21 to 228 microg/mL.

Animals↗

Treatment of Bowen's disease with a specially designed radioactive skin patch.

Bowen's disease can be treated by various methods, including surgical excision, cryosurgery, laser ablation, curettage, Mohs' microsurgery and ionizing radiation. Radiotherapy has been a useful therapeutic modality in the treatment of Bowen's disease and other skin cancers in areas which are difficult to excise, especially the central areas of the face, including eyelids, nose and lips. To overcome some of the disadvantages of external radiotherapy, a specially designed skin patch coated with high-energy beta-emitter holmium-166 was made for topical application at our institute. Twenty-nine sites of Bowen's disease in eight patients, confirmed by skin biopsy, were treated with 166Ho patches. The patches were applied to the surface of skin cancers for 30-60 min for a total radiation dose of 35 Gy (3500 rads). One to two weeks after application of the 166Ho patch, desquamation, erythema or erosion developed in treated sites, but these acute radiation reactions healed gradually with epithelial regeneration, and they showed good functional and cosmetic results without any complications. Follow-up biopsies were performed 1-5 months after 166Ho patch therapy, and they did not show any signs of Bowen's disease. One to two years after treatment with 166Ho skin patches, there were no recurrences of Bowen's diseases and no late complications. The 166Ho patch is an effective and convenient alternative method for the treatment of Bowen's disease that yields good cosmetic and functional results.

Aged↗