A Porphyrin-Based 3D Metal-Organic Framework Featuring [Cu8Cl6]10+ Cluster Secondary Building Units: Synthesis, Structure Elucidation, Anion Exchange, and Peroxidase-Like Activity

Herein, we report a rare example of cationic three-dimensional (3D) metal-organic framework (MOF) of [Cu5Cl3(TMPP)]Cl5 ⋅ xSol (denoted as Cu-TMPP; H2TMPP=meso-tetrakis (6-methylpyridin-3-yl) porphyrin; xSol=encapsulated solvates) supported by [Cu8Cl6]10+ cluster secondary building units (SBUs) wherein the eight faces of the Cl--based octahedron are capped by eight Cu2+. Surface-area analysis indicated that Cu-TMPP features a mesoporous structure and its solvate-like Cl- counterions can be exchanged by BF4 -, PF6 -, and NO3 -. The polyvinylpyrrolidone (PVP) coated Cu-TMPP (denoted as Cu-TMPP-PVP) demonstrated good ROS generating ability, producing ⋅OH in the absence of light (peroxidase-like activity) and 1O2 on light irradiation (650 nm; 25 mW cm-2). This work highlights the potential of Cu-TMPP as a functional carrier of anionic guests such as drugs, for the combination therapy of cancer and other diseases.

Benzopyrone-mediated quinolones as potential multitargeting antibacterial agents

A new type of benzopyrone-mediated quinolones (BMQs) was rationally designed and efficiently synthesized as novel potential antibacterial molecules to overcome the global increasingly serious drug resistance. Some synthesized BMQs effectively suppressed the growth of the tested strains, outperforming clinical drugs. Notably, ethylidene-derived BMQ 17a exhibited superior antibacterial potential with low MICs of 0.5-2 μg/mL to clinical drugs norfloxacin, it not only displayed rapid bactericidal performance and inhibited bacterial biofilm formation, but also showed low toxicity toward human red blood cells and normal MDA-kb2 cells. Mechanistic investigation demonstrated that BMQ 17a could effectually induce bacterial metabolic disorders and promote the enhancement of reactive oxygen species to disrupt the bacterial antioxidant defense system. It was found that the active molecule BMQ 17a could not only form supramolecular complex with lactate dehydrogenase, which disturbed the biological functions, but also effectively embed into calf thymus DNA, thus affecting the normal function of DNA and achieving cell death. This work would provide an insight into developing new molecules to reduce drug resistance and expand antibacterial spectrum.

The effects of rate pressure product at admission on cardiopulmonary function during hospitalization in patients with acute myocardial infarction

OBJECTIVE

This study aimed to analyze the correlation between the rate pressure product (RPP) and cardiopulmonary function during hospitalization in patients with acute myocardial infarction (AMI).

METHODS

A total of 362 patients with AMI were selected for the study, and the median admission RPP was used as the cutoff point to divide the patients into a low-RPP group (n = 181) and a high-RPP group (n = 181). The relationship between the RPP at admission and the cardiopulmonary function during hospitalization was analyzed.

RESULTS

The patients in the high-RPP group had a higher body mass index (BMI) (p = 0.014), a higher prevalence of combined hypertension and diabetes mellitus (p < 0.001), a lower incidence of smoking (p = 0.044), and a higher incidence of oscillatory ventilation (6.1% vs. 1.7%, p = 0.029). The differences in RPP at rest, during warm-up, and within 1 and 4 minutes of recovery were statistically significant between the two groups (p < 0.01 on each occasion), while the differences in anaerobic threshold (AT) and watt max (Max) were not statistically significant (p > 0.05 for both). The patients in the low-RPP group had higher oxygen uptake (VO2 [AT]: 14.9 ± 3.4 vs. 14.2 ± 3.6, p = 0.048) and (VO2peak [Max]:18.2 ± 3.8 vs. 17.3 ± 3.8, p = 0.020). The RPP at admission was negatively correlated with VO2 (AT) and VO2peak (p < 0.05) using the regression Equation VO2peak = 33.682 + (-0.012 * RPP at admission/100) + (-0.105 * Age) + (-0.350 * BMI), while there was no correlation between the RPP at admission and VO2 (AT) (p = 0.149).

CONCLUSION

The RPP at admission was negatively correlated with cardiopulmonary function during hospitalization in patients with AMI. Patients with a high RPP were more likely to have a combination of obesity, hypertension, diabetes mellitus, and reduced oxygen uptake during exercise, while a high RPP at admission appeared to affect their cardiovascular response indicators during exercise.

The relationship between homocysteine and cardiopulmonary exercise testing in patients with acute coronary syndrome after percutaneous coronary intervention

OBJECTIVE

The purpose of this study was to investigate the relationship between homocysteine (Hcy) levels and cardiopulmonary exercise testing (CPET) in patients with acute coronary syndrome (ACS) after percutaneous coronary intervention (PCI). We also explored the relationship between Hcy levels and cardiac ultrasonography.

METHODS

This study comprised 261 patients with ACS who underwent coronary angiography and PCI at Yulin First Hospital from January 2020 to June 2021. All subjects completed basic data collection, laboratory examination, CPET and cardiac ultrasonography. The CPET includes the peak oxygen uptake (peak VO₂), anaerobic threshold (AT), metabolic equivalents (METs), exercise load (load), oxygen pulse (O₂ pulse), end-tidal CO₂ partial pressure (PETCO₂), ventilatory equivalents for carbon dioxide (VE/VCO₂) and Oxygen uptake efficiency (OUES). Cardiac ultrasonography was used to evaluate the left ventricular end diastolic diameter (LVEDD), interventricular septal thickness (IVST), left ventricular posterior wall thickness (LVPWT) and left ventricular ejection fraction (LVEF). A serum Hcy level ≥ 15 µmol/L was defined as hyperhomocysteinemia (HHcy). The patients were divided into the Hcy < 15 µmol/L group (n = 189) and the Hcy ≥ 15 µmol/L group (n = 72).

RESULTS

The average age of the participating patients was 58.9 ± 10.1 years. The majority of participants were male (86.6%). The CPET indices of METs, load, VO₂/kg, and PETCO₂ were significantly decreased in the Hcy ≥ 15 µmol/L group compared with the Hcy < 15 µmol/L group. Additionally, the CPET index of the VE/VCO₂ slope and the cardiac ultrasonography indices of IVST and LVPWT were significantly increased in the Hcy ≥ 15 µmol/L group compared with the Hcy < 15 µmol/L group. These differences were statistically significant (P < 0.05). Correlation analysis showed that Hcy levels were negatively correlated with METs, VO₂/kg and PETCO₂ and positively correlated with the VE/VCO₂ slope (P < 0.05). Partial correlation analysis showed that Hcy levels were negatively correlated with METs and VO₂/kg in the AT state. The correlation coefficients were - 0.172 and - 0.172, respectively (P < 0.05). Hcy levels were negatively correlated with METs, VO₂/kg and PETCO₂ in the peak state. The correlation coefficients were - 0.177, -0.153 and - 0.129, respectively (P < 0.05). After further adjustment for confounders, multiple linear regression analysis showed that Hcy levels were negatively correlated with METs and VO₂/kg in the AT state and peak state. The standardized regression coefficients were - 0.035, -0.122, -0.048 and - 0.128, respectively (P < 0.05). Correlation analysis showed that Hcy levels were positively correlated with the IVST and LVPWT (P < 0.05), but after adjusting for confounding factors, partial correlation analysis showed that there was no correlation between them.

CONCLUSION

A high Hcy level is associated with lower METs and VO₂/kg and worse cardiopulmonary function in patients with ACS after PCI.

Living near greenness is associated with higher bone strength: A large cross-sectional epidemiological study in China

BACKGROUND

Living near green spaces may benefit various health outcomes. However, no studies have investigated the greenness-bone linkage in the general population. Moreover, to which extent ambient air pollution (AAP), physical activity (PA), and body mass index (BMI) mediate this relationship remains unclear. We aimed to explore the association between greenness and bone strength and the potential mediating roles of AAP, PA, and BMI in Chinese adults.

METHODS

This cross-sectional analysis enrolled 66,053 adults from the China Multi-Ethnic Cohort in 2018-2019. The normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) were employed to define residential greenness. The calcaneus quantitative ultrasound index (QUI) was used to indicate bone strength. Multiple linear regression models and mediation analyses were used to estimate the residential greenness-bone strength association and potential pathways operating through AAP (represented by PM_2.5 [particulate matter <2.5 μm in diameter]), PA, and BMI. Stratification analyses were performed to identify susceptible populations.

RESULTS

Higher residential exposure to greenness was significantly associated with an increase in QUI, with changes (95% confidence interval) of 3.28 (3.05, 3.50), 3.57 (3.34, 3.80), 2.68 (2.46, 2.90), and 2.93 (2.71, 3.15) for every interquartile range increase in NDVI_500m, NDVI_1000m, EVI_500m, and EVI_1000m, respectively. Sex, urbanicity, annual family income, smoking, and drinking significantly modified the association of greenness-bone strength, with more remarkable associations in males, urban residents, subjects from wealthier families, smokers, and drinkers. For the NDVI_500m/EVI_500m-QUI relationship, the positive mediating roles of PM_2.5 and PA were 6.70%/8.50 and 2.43%/2.69%, respectively, whereas those negative for BMI and PA-BMI were 0.88%/1.06% and 0.05%/0.05%, respectively.

CONCLUSION

Living in a greener area may predict higher bone strength, particularly among males, urban residents, wealthier people, smokers, and drinkers. AAP, PA, BMI, and other factors may partially mediate the positive association. Our findings underscore the importance of optimizing greenness planning and management policies.

Cardiopulmonary exercise test-based assessment of the effects of sacubitril/valsartan on the blood pressure response to exercise in patients with acute myocardial infarction during hospitalization

OBJECTIVE

To investigate the effects of sacubitril/valsartan (S/V) on cardiopulmonary function and blood pressure response to exercise during hospitalization in patients with acute myocardial infarction (AMI) based on the cardiopulmonary exercise test (CPET).

METHODS

A total of 265 AMI patients were treated with either perindopril or S/V within 24 hours of admission. CPET was completed for all patients before discharge. There were 182 cases in the perindopril group and 83 cases in the S/V group.

RESULTS

The proportion of exercise oscillatory ventilation (EOV) was higher in the S/V group than in the perindopril group (10.8% vs 1.6%, X² = 11.148, P = .001). The resting heart rate (HR), resting diastolic blood pressure (DBP), and warm-up DBP were lower in the S/V group than in the perindopril group (P < .05). The resting systolic blood pressure (SBP) was 9.0 mmHg lower (115.7 ± 17.5 vs 106.7 ± 15.0, P < .001), the SBP during warm-up was 9.5 mmHg lower (124.8 ± 23.7 vs 115.3 ± 22.5,P = .002), the SBP at the anaerobic threshold (AT) was 10.5 mmHg lower (135.3 ± 24.8 vs 127.1 ± 25.1,P = .021),the SBP at max watts was 11.5 mmHg lower (148.9 ± 26.4 vs 137.4 ± 26.4,P = .001), and the SBP during one-minute recovery was 12.3 mmHg lower (146.5 ± 27.1 vs 134.2 ± 24.4, P = .001)in the S/V group than in the perindopril group. The S/V group had a higher oxygen ventilation equivalent and carbon dioxide ventilation equivalent (VE/VCO₂) at AT and a lower oxygen uptake-work rate relationship during max watts (P < .05). The differences in the oxygen pulse, stroke volume, peak oxygen uptake (VO_{2 peak}), and VE/VCO₂ slope were not statistically significant between the two groups.

CONCLUSION

Treatment with S/V was able to reduce the exercise blood pressure in patients with AMI during hospitalization, but did not significantly improve the VO_{2 peak}, VE/VCO₂ slope, or exercise tolerance.

Reduction in risk of contrast-induced nephropathy in patients with chronic kidney disease and diabetes mellitus by enhanced external counterpulsation

OBJECTIVE

To evaluate the efficacy of enhanced external counterpulsation (EECP) in the prevention of contrast-induced nephropathy (CIN) in patients with combined chronic kidney disease (CKD) and diabetes mellitus (DM) by comparing the changes in renal function-related indicators in patients before and after coronary angiography (CAG) or percutaneous coronary intervention (PCI).

METHODS

There were 230 subjects consecutively included in the study. Of these, 30 cases with DM underwent rehydration therapy, and 200 cases underwent EECP therapy in addition to rehydration therapy, comprising 53 patients with DM and 147 patients without. All the patients were tested to measure the renal function indicators before and after CAG/PCI.

RESULTS

The postoperative results of blood urea nitrogen (BUN), serum creatinine (Scr), estimated glomerular filtration rate (eGFR), B2 microglobulin, and high-sensitivity C-reactive protein in the three groups showed a statistically significant difference (P < 0.05). After EECP therapy, patients with DM showed a significant decrease in BUN (9.1 ± 4.2 vs. 7.2 ± 3.0, t = 3.899, P < 0.001) and a significant increase in eGFR (41.5 ± 12.7 vs. 44.0 ± 15.6, t = -2.031, P = 0.047), while the patients without DM showed a more significant difference (P < 0.001). Patients with DM showed a lower percentage of elevated Scr (66.7% vs. 43.4%, P = 0.042), a higher percentage of elevated eGFR (30.0% vs. 52.8%, P = 0.044), and a lower incidence of CIN (16.7% vs. 3.8%, P = 0.042) after EECP therapy.

CONCLUSION

Treatment with EECP can reduce Scr in patients with combined CKD and DM post CAG/PCI, increase eGFR, and decrease the incidence of CIN.

Effects on gamma-aminobutyric acid (GABA)(A) receptors of a neuroactive steroid that negatively modulates glutamate neurotransmission and augments GABA neurotransmission

Neurosteroids positively and negatively modulate gamma-aminobutyric acid (GABA)(A) receptors and glutamate receptors, which underlie most fast inhibition and excitation in the central nervous system. We report the identification of a neuroactive steroid, (3 alpha,5 beta)-20-oxo-pregnane-3-carboxylic acid (3 alpha 5 beta PC), with unique cellular actions. 3 alpha 5 beta PC positively modulates GABA(A) receptor function and negatively modulates N-methyl-D-aspartate (NMDA) receptor function, a combination that may be of particular clinical benefit. 3 alpha 5 beta PC promotes net GABA(A) potentiation at low steroid concentrations (<10 microM) and at negative membrane potentials. At higher concentrations, the steroid also blocks GABA receptors. Because this block would presumably counteract the NMDA receptor blocking actions of 3 alpha 5 beta PC, we characterize the GABA receptor block in some detail. Agonist concentration, depolarization, and high extracellular pH increase the block. The apparent pK for both potentiation and block was 6.4 to 6.9, substantially higher than expected from carboxylated steroid in an aqueous environment. Block is not dependent on the stereochemistry of the carboxylic acid at carbon 3 and is relatively insensitive to placement of the carboxylic acid at the opposite end of the steroid (carbon 24). Potentiation is critically dependent on the stereochemistry of the carboxylic acid group at carbon 3. Consistent with the pH dependence of potentiation, effects of the amide derivative (3 alpha,5 beta)-20-oxo-pregnane-3-carboxamide, suggest that the un-ionized form of 3 alpha 5 beta PC is important for potentiation, whereas the ionized form is probably responsible for block. Further refinement of the neuroactive steroid to promote GABA potentiation and NMDA receptor block and diminish GABA receptor block may lead to a clinically useful neuroactive steroid.

Conversion between two cytochalasin B-binding states of the human GLUT1 glucose transporter

Two cytochalasin B-binding states of the human red blood cell facilitative glucose transporter GLUT1 were studied, one exhibiting one cytochalasin B-binding site on every second GLUT1 monomer (state 1) and the other showing one site per monomer (state 2). Quantitative affinity chromatography of cytochalasin B was performed on (a) biotinylated red blood cells, (b) cytoskeleton-depleted red blood cell membrane vesicles, and (c) GLUT1 proteoliposomes. The cells were adsorbed on streptavidin-derivatized gel beads, and the vesicles and proteoliposomes entrapped in dextran-grafted agarose gel beads. Cytochalasin B binding to free vesicles and proteoliposomes was analyzed by Hummel and Dreyer size-exclusion chromatography and ultracentrifugation. Analysis of the biotinylated cells indicated an equilibrium between the two GLUT1 states. GLUT1 in free membrane vesicles attained state 2, but was converted into state 1 on entrapment of the vesicles. Purification of GLUT1 in the presence of non-ionic detergent followed by reconstitution produced GLUT1 in state 1. This state was maintained after entrapment of the proteoliposomes. Finally, GLUT1 showed slightly higher affinity for cytochalasin B in state 1 than in state 2. In summary, the cytochalasin B-binding state of GLUT1 seemed to be affected by (a) biotinylation of the cell surface, (b) removal of the cytoskeleton at high pH and low ionic strength, (c) interaction between the dextran-grafted agarose gel matrix and the membrane vesicles, and (d) reconstitution to form proteoliposomes.

Increased detectability of alpha brain glutamate/glutamine in neonatal hypoxic-ischemic encephalopathy

BACKGROUND AND PURPOSE

Proton MR spectroscopy (MRS) detectability of brain glutamate/glutamine (Glx) is increased in hypoxic-ischemic insults and is implicated in the neuronal injury and death that follows. Our aim was to correlate the proton MRS detectability of alpha-CH protons of Glx (alpha-Glx) with the Sarnat stage of neonatal hypoxic-ischemic encephalopathy (HIE).

METHODS

Initial and follow-up proton MRS studies at 1.9 T were performed in 28 neonates aged 1 to 7 days (seven healthy control subjects and 21 with HIE: 10 mild, nine moderate, and two severe) and in 12 neonates aged 13 to 17 days (12 with HIE: eight mild, three moderate, and one severe), respectively. Both point-resolved spectroscopy (PRESS) and stimulated-echo acquisition mode (STEAM) sequences were used. The spectral volume of interest was in the basal ganglia, thalami, and adjoining regions. The detectability of alpha-Glx was assessed by two different parameters: the detection rate of the alpha-Glx peak and the peak-area ratio of alpha-Glx to creatine and phosphocreatine.

RESULTS

On both the initial and follow-up PRESS studies, all the neonates with moderate and severe HIE showed an alpha-Glx peak, compared with one healthy control subject in the initial study and one neonate with mild HIE in both the studies. They also demonstrated a significantly higher peak-area ratio of alpha-Glx/(creatine and phosphocreatine) on both the initial and follow-up studies. The peak-area ratios in neonates with HIE positively correlated with the Sarnat stage of HIE on both the initial and follow-up studies. Neonates with moderate and severe HIE also showed a consistently higher alpha-Glx peak on both the initial and follow-up studies with the STEAM sequence.

CONCLUSION

Proton MRS detectability of alpha-Glx is increased in moderate and severe HIE and correlates with the Sarnat stage of HIE.

Chromatographic approaches to liposomes, proteoliposomes and biomembrane vesicles

Size-exclusion chromatography has been used for fractionation of liposomes, proteoliposomes and biomembrane vesicles of up to approximately 500 nm in size and for separation of these entities from smaller components. Liposome sizes, encapsulation stability, and solute affinities for membrane proteins have been determined. Counter-current distribution in aqueous two-phase systems has widened the range of applications to larger structures. Immobilized biomembrane vesicles and (proteo)liposomes provide stationary phases for chromatographic analysis of specific or nonspecific membrane-solute interactions.

Biomembrane affinity chromatographic analysis of inhibitor binding to the human red cell nucleoside transporter in immobilized cells, vesicles and proteoliposomes

The affinity of the human red cell nucleoside transporter for the transport inhibitor nitrobenzylthioinosine decreases upon protein purification. The affinity was highest for the whole cells (Kd, 0.04 nM), lowered upon cytoskeleton depletion (Kd, 0.2 nM) and lowest after partial purification and reconstitution (Kd, 0.3 nM), as determined by frontal affinity chromatography.

D-Glucose, forskolin and cytochalasin B affinities for the glucose transporter Glut1. Study of pH and reconstitution effects by biomembrane affinity chromatography

The affinities of D-glucose and the transport inhibitors, forskolin and cytochalasin B (CB), for Glut1 were studied by frontal affinity chromatography at pH 5-10 on sterically immobilized proteoliposomes with reconstituted human red cell glucose transporter Glut1. The affinity of D-glucose for Glut1 became slightly weaker as the pH was increased. The inhibitor affinities decreased and became immeasurably weak above pH 9. At pH 7.4, the dissociation constants were 44 mM for glucose, 1.8 microM for forskolin and 72 nM for CB. The affinities of these solutes for Glut1 in red cell membrane vesicles and particularly for Glut1 in red cells were higher, as shown by chromatographic analyses.

Immobilization of human red cells in gel particles for chromatographic activity studies of the glucose transporter Glut1

Chromatography on a novel stationary phase, human red cells immobilized in a gel bed, was introduced for analysis of activities of the glucose transporter Glut1 in the cell membrane. A gel containing positively charged ligands was synthesized from derivatized acrylamide monomers. Red cells were immobilized in gel particles which were packed into a column tube for chromatographic analyses over periods of 10-15 days. D-Glucose was separated from L-glucose on a 1.1-ml bed with a retention volume difference of 0.23 ml, approximately equal to the total inner volume of immobilized intact cells and of ghosts probably formed from lysed cells during the immobilization. The separation was suppressed by the glucose-transport inhibitor cytochalasin B. The interactions between D-glucose, the transport inhibitor forskolin and Glut1 were analyzed by quantitative frontal affinity chromatography. The dissociation constants at room temperature were 6.8 mM for D-glucose binding and 1.8 microM for glucose-displaceable binding of forskolin, in good agreement with published values. The results suggest that chromatography on immobilized cells is a potentially useful tool for studies on cellular membrane functions.

Immobilized liposome chromatography of drugs on capillary continuous beds for model analysis of drug-membrane interactions

Liposomes were immobilized in capillary continuous beds with covalently linked C4 or C8 alkyl ligands for chromatographic analysis of drug interaction with phospholipid bilayers, as reflected by drug retention volumes and calculated differences in interaction free energies. This procedure is a high-resolution micro-scale version of immobilized liposome chromatography for prediction of diffusion of drugs across biological membranes. The logarithm of the specific capacity factors of several structurally unrelated drugs showed a linear correlation with the logarithm of known apparent drug permeabilities through Caco-2 epithelial cell monolayers. The latter values are used for prediction of absorption of orally administered drug doses.

Continuous beds for microchromatography: detection of proteins by a blotting membrane technique

Continuous beds have been used as matrices for cation- and anion-exchange chromatography of proteins on columns with an i.d. in the range of 0.005-0.015 mm. On-tube uv detection is not feasible at low protein concentrations with these narrow-bore columns. Therefore, a more sensitive detection system has been developed based on blotting technique: as the protein zones leave the microcolumn chromatographically they become adsorbed onto a rotating polyvinylidene difluoride blotting membrane. The protein spots can then be visualized by means of Coomassie brilliant blue, immunomethods, and other standard techniques. By using an immunomethod 0.015 ng of human transferrin can easily be detected. The blotting membrane can be washed with water without loss of adsorbed protein. This is an attractive feature because the presence of salts, etc., diminishes the accuracy in the determination of molecular weights of proteins by mass spectrometry. The microcolumns are easy to prepare. A solution of appropriate monomers is sucked into a piece of fused silica tubing. The rod formed upon polymerization contains channels through which the eluent can pass. No supporting frit is required because the polymer rod is anchored by covalent bonds to the tubing wall.

Biemnasterol, a new cytotoxic sterol with the rare 22,25-diene side chain, isolated from the marine sponge Biemna sp

Biemnasterol [2], a new sterol with a 22,25-diene side chain possessing cytotoxic activity, has been isolated from the Okinawan marine sponge Biemna sp. and the structure elucidated on the basis of spectroscopic data and chemical means.