Optimization of Flow Imaging Microscopy Setting Using Spherical Beads with Optical Properties Similar to Those of Biopharmaceuticals.

Flow imaging microscopy (FIM) is widely used to characterize biopharmaceutical subvisible particles (SVPs). The segmentation threshold, which defines the boundary between the particle and the background based on pixel intensity, should be properly set for accurate SVP quantification. However, segmentation thresholds are often subjectively and empirically set, potentially leading to variations in measurements across instruments and operators. In the present study, we developed an objective method to optimize the FIM segmentation threshold using poly(methyl methacrylate) (PMMA) beads with a refractive index similar to that of biomolecules. Among several candidate particles that were evaluated, 2.5-µm PMMA beads were the most reliable in size and number, suggesting that the PMMA bead size analyzed by FIM could objectively be used to determine the segmentation threshold for SVP measurements. The PMMA bead concentrations measured by FIM were highly consistent with the indicative concentrations, whereas the PMMA bead size analyzed by FIM decreased with increasing segmentation threshold. The optimal segmentation threshold where the analyzed size was closest to the indicative size differed between an instrument with a black-and-white camera and that with a color camera. Inter-instrument differences in SVP concentrations in acid-stressed recombinant adeno-associated virus (AAV) and protein aggregates were successfully minimized by setting an optimized segmentation threshold specific to the instrument. These results reveal that PMMA beads can aid in determining a more appropriate segmentation threshold to evaluate biopharmaceutical SVPs using FIM.

Air exchange rates and advection-diffusion of CO2 and aerosols in a route bus for evaluation of infection risk.

As COVID-19 continues to spread, infection risk on public transport is concerning. Air exchange rates (ACH) and advection-diffusion of CO2 and particles were determined in a route bus to evaluate the infection risk. ACH increased with bus speed whether windows were open or closed, and ACH were greater when more windows were open. With two open windows, ACH was greater when a front and rear window were open than when two rear windows were open. With both front and rear ventilation fans set to exhaust, ACH was more than double that when both were set to supply. With air conditioning (AC) off, CO2 and particles spread proportionally at the same rate from a source, whereas with the AC on, the spread rate of particles was about half that of CO2 , because particles might be trapped by a prefilter on the AC unit. Infection risk can be reduced by equipping AC unit with an appropriate filter. Calculations with a modified Wells-Riley equation showed that average infection risk was reduced by 92% in the moving bus with windows open comparing to with windows closed. When the bus was moving with windows closed, exhaust fan operation reduced the average risk by 35%.

Determination of the Rayleigh Ratio with an Uncertainty Analysis by Static Light-Scattering Measurements of Certified Reference Materials for Molecular Weight.

The most important parameter for light-scattering measurements in the Rayleigh scattering region is the Rayleigh ratio, which is necessary to obtain the absolute scattered light intensity from the relative scattered light intensity. The absolute scattered light intensity is directly related to the molar masses of polymers, colloids, biomolecules, and the like. A new Rayleigh ratio was determined by measuring static light scattering from certified reference materials with highly accurate certified values of the molecular weight determined by several other techniques, such as MALDI-TOF mass spectrometry or size-exclusion chromatography. The new Rayleigh ratio can be used for evaluating the uncertainty of the molecular weight of polymers and macromolecules, as measured by light scattering.

Simultaneous determination of the size and concentration of fine bubbles in water by laser-light scattering.

The preparation of nanoscale fine bubbles in water is an innovative technology, but no precise method for simultaneously measuring the size and concentration of such bubbles had previously been developed. We have developed a method for simultaneously determining the size and concentration of fine bubbles in water by a light-scattering technique. Dynamic light scattering gives the diffusion constant and particle size of fine bubbles, whereas static light scattering provides their concentration or molar mass. Static light scattering also provides the radius of gyration of the bubbles, thereby providing a means for validating measurements of the sizes of the fine bubbles.

Direct analysis of ultra-trace semiconductor gas by inductively coupled plasma mass spectrometry coupled with gas to particle conversion-gas exchange technique.

An inductively coupled plasma mass spectrometry (ICPMS) coupled with gas to particle conversion-gas exchange technique was applied to the direct analysis of ultra-trace semiconductor gas in ambient air. The ultra-trace semiconductor gases such as arsine (AsH3) and phosphine (PH3) were converted to particles by reaction with ozone (O3) and ammonia (NH3) gases within a gas to particle conversion device (GPD). The converted particles were directly introduced and measured by ICPMS through a gas exchange device (GED), which could penetrate the particles as well as exchange to Ar from either non-reacted gases such as an air or remaining gases of O3 and NH3. The particle size distribution of converted particles was measured by scanning mobility particle sizer (SMPS) and the results supported the elucidation of particle agglomeration between the particle converted from semiconductor gas and the particle of ammonium nitrate (NH4NO3) which was produced as major particle in GPD. Stable time-resolved signals from AsH3 and PH3 in air were obtained by GPD-GED-ICPMS with continuous gas introduction; however, the slightly larger fluctuation, which could be due to the ionization fluctuation of particles in ICP, was observed compared to that of metal carbonyl gas in Ar introduced directly into ICPMS. The linear regression lines were obtained and the limits of detection (LODs) of 1.5 pL L(-1) and 2.4 nL L(-1) for AsH3 and PH3, respectively, were estimated. Since these LODs revealed sufficiently lower values than the measurement concentrations required from semiconductor industry such as 0.5 nL L(-1) and 30 nL L(-1) for AsH3 and PH3, respectively, the GPD-GED-ICPMS could be useful for direct and high sensitive analysis of ultra-trace semiconductor gas in air.

Structural and redox requirements for the action of anti-diabetic vanadium compounds.

This study presents the first systematic investigation of the anti-diabetic properties of non-oxido V(IV) complexes. In particular, the insulin-mimetic activity of [V(IV)(taci)2](4+), [V(IV)(inoH-3)2](2-), [V(IV)(dhab)2], [V(IV)(hyph(Ph))2], [V(IV)(cat)3](2-) and [V(IV)(pdbh)2]--where taci is 1,3,5-triamino-1,3,5-trideoxy-cis-inositol, ino is cis-inositol, H2dhab is 2,2'-dihydroxyazobenzene, H2hyph(Ph) is 3,5-bis(2-hydroxyphenyl)-1H-1,2,4-triazole, H2cat is catechol and H2pdbh is pentan-2,4-dione benzoylhydrazone--was evaluated in terms of free fatty acid (FFA) release. Among the six compounds examined, only [V(IV)(pdbh)2], [V(IV)(cat)3](2-) and [V(IV)(hyph(Ph))2], which at the physiological pH convert to the corresponding V(IV)O complexes, were found to exhibit a significant insulin-mimetic activity compared to VOSO4. In contrast, [V(taci)2](4+), [V(inoH-3)2](2-) and [V(dhab)2], which at pH 7.4 keep their 'bare' non-oxido structure, did not cause any inhibition of FFA. The results, therefore, suggest that a V(IV)O functionality is necessary for vanadium complexes to exhibit anti-diabetic effects. This agrees with the notion that the biotransformations of V compounds in the organism are more important than the nature of the species.

[Copper compounds ameliorate cardiovasclur dysfunction and diabetes in animals].

Copper (Cu) is essential for our daily life and it is found at approximately 110 mg in human adults with the body weight of 70 kg, in which this metal occurs at 46 mg in the bone and 26 mg in the muscle. Although Cu exists in the brain (approximately 5 mg/kg), liver (6 mg/kg), kidney (13 mg/kg), erythrocytes (90 mg/L), bile (6 mg/L) and serum (120 mg/L), its organ-specific distribution is not yet known. In metalloenzymes such as oxidoreductases, Cu is abundantly found and greatly contributes in life functions. In addition, intracellular Cu transport system has been revealed in connection with iron (Fe) and zinc (Zn) intracellular transport systems. In spite of such great contribution of Cu in life, no Cu-containing pharmaceutics have yet been known. Under such background, the author and his research group have tried to examine a possibility of Cu compounds as potential pharmaceutics. In the review, the following topics are concerned; (1) improvement of cardiovascular dysfunction in animals by di-nuclear Cu-asprinate complex on the basis of the results on its reactive oxygen scavenging (ROS) effect, (2) blood glucose-lowering effect of mono-nuclear Cu-picolinate complex in streptozotocin (STZ)-induced type 1-like diabetic animals, based on the results on in vitro insulinomimetic activity, and (3) anti-diabetic effect of copper sulfate in animals with regard to the inhibition of α-glucosidase activity. These results suggest that copper ion and its complexes are possible seeds for developing Cu-containing pharmaceutics in the future.

Investigation of the insulin-like properties of zinc(II) complexes of 3-hydroxy-4-pyridinones: identification of a compound with glucose lowering effect in STZ-induced type I diabetic animals.

Results from an investigation in an in vivo model of STZ-induced diabetic rats demonstrate that compound bis(1,2-dimethyl-3-hydroxy-4(1H)-pyridinonate)zinc(II), Zn(dmpp)(2), significantly lowers the blood glucose levels of individuals, thus showing evidence of glucose lowering activity. The compound was selected from a set of eight zinc(II) complexes of 3-hydroxy-4-pyridinones with diverse lipophilicity that were prepared and characterized in our laboratory. Assessment of insulin-like activity of the complexes was firstly performed in vitro by measuring the inhibition of FFA release in isolated rat adipocytes. The results indicate that compounds bis(2-methyl-3-hydroxy-4-pyridinonate)zinc(II), Zn(mpp)(2) and Zn(dmpp)(2) display significantly higher activity than that of the respective positive control thus suggesting its selection for in vivo tests. Safety evaluation of the active zinc(II) compounds was performed in freshly isolated rat hepatocytes. The results support that cell viability is not significantly different from the control set after 1 and 2h of incubation with both zinc(II) complexes.

Oral administration of Bis(aspirinato)zinc(II) complex ameliorates hyperglycemia and metabolic syndrome-like disorders in spontaneously diabetic KK-A(y) mice: structure-activity relationship on zinc-salicylate complexes.

In recent years, the number of patients suffering from diseases, such as cancer, apoplexy, osteoporosis, hypertension, and type 2 diabetes mellitus is increasing worldwide. Type 2 diabetes, a lifestyle-related disease, is recognized as a serious disease. Various types of pharmaceutics for diabetes have been used. Since the relationship between diabetes and biometals such as vanadium, copper, and zinc ions has been recognized for many years, we have been developing the anti-diabetic metal complexes as new candidates. We found that several zinc(II) (Zn) complexes exhibit glucose-lowering activity for treating type 2 diabetes. High doses of salicylates have been known to reverse hyperglycemia and hyperinsulinemia in type 2 diabetic patients. These findings strongly suggest that the combined use of Zn and salicylates achieves the synergism in treating type 2 diabetes. Because aspirin, acetyl salicylic acid, has a chelating ability, we used it as a ligand to Zn. Several Zn-salicylate complexes were prepared and their biological activities were examined in this study. The complexes with an electron-withdrawing group in the ligand exhibited higher in vitro insulinomimetic activity than those of Zn complexes with an electron-donating group in the ligand. When bis(aspirinato)Zn (Zn(asp)2) complex was orally administered on KK-A(y) mice with hereditary type 2 diabetes, the diabetic state was improved. In addition, this complex exhibited normalizing effects on serum adiponectin level and high blood pressure in metabolic syndrome. In conclusion, Zn(asp)2 complex is newly proposed as a potent anti-diabetic and anti-metabolic syndrome agent.

[Improved spectrophotometric determination of total iron and iron(III) with o-hydroxyhydroquinonephthalein and their characterization].

Simultaneous and fractional determination of iron(II) and iron(III) was accomplished with o-hydroxyhydroquinonephthalein (QP) in the presence of poly (N-vinyl pyrrolidone). In the determination of total iron (iron(II)+iron(III)), Beer's law was obeyed in the range of 0.02-0.67 µg·ml(-1), with an effective molar absorptivity (at 570 nm) and a relative standard deviation of 1.30×10(5)·l·mol(-1)·cm(-1) and 0.77% (n = 8), respectively. This method was about 10-15 times and more than the methods using 1,10-phenanthroline and 2,2'-bipyridine. In addition, the iron-QP complex was characterized using spectrophotometry and the electron spin resonance. This method was successfully applied to assays of total iron and iron(III) in pharmaceutical preparations.

[Challenge of studies on the development of new Zn complexes to treat diabetes mellitus].

In recent years, people all over the world have suffered from various diseases such as cancer, myocardial infarction, osteoporosis, hypertension, and diabetes mellitus (DM). Especially, DM, well-known as one of lifestyle-related diseases, has been regarded as a serious problem, because it is difficult to fully recover. The number of patients suffering from DM in 2007 was reported to be approximately 200 million people worldwide. However, insulin preparations and synthetic therapeutics, which are clinically used treatment of DM, have been associated with problems such as physical and mental pain due to daily injections and certain severe side effects, respectively. Zn, which is an essential trace element in animals and humans and plays an important role in maintenance of their lives, has been indicated to exhibit insulin-like activity. Since the finding of insulin-like effects of Zn, several Zn complexes have been proposed as a new type of anti-diabetic therapeutics which is differ from existing medicines. In this symposium, we introduce the anti-diabetic effect, complication relieving effect, and action mechanism of bis(2-mercaptopyridine-N-oxidato)Zn complex with Zn(S(2)O(2)) coordination mode.

Challenge of studies on the development of new Zn complexes (Zn(opt)2) to treat diabetes mellitus.

The number of worldwide patients suffering from diabetes mellitus (DM) is forecasted to increase over time. The development of compounds without severe side effects for type 2 DM is required not only to treat DM but also to improve the quality of life (QOL) of patients. In this paper, we have described the synthesis of novel first transition metal complexes with S2O2 coordination mode and discussed their anti-diabetic activities. Di(1-oxy-2-pyridinethiolato)Zn complex (Zn(opt)2) with Zn(S2O2) coordination mode displayed higher insulin mimetic with anti-diabetic activity, compared to the ZnCl2 or clinically used medicine (pioglitazone). In addition, Zn(opt)2 improved the insulin and adiponectine levels in the plasma. The gastrointestinal absorption of the Zn complex was found to be higher than that of ZnCl(2). Based on these results, we propose that the Zn(opt)2 complex with Zn(S2O2) coordination mode is a novel candidate for the treatment of type 2 DM; through oral administration.

Metallo-allixinate complexes with anti-diabetic and anti-metabolic syndrome activities.

Metabolic syndrome and the accompanied diabetes mellitus are both important diseases worldwide due to changes of lifestyle and eating habits. The number of patients with diabetes worldwide is estimated to increase to 300 million by 2025 from 150-220 million in 2010. There are two main types of diabetes. In type 1 diabetes, caused by destruction of pancreatic ß-cells resulting in absolute deficiency of intrinsic insulin secretion, the patients require exogenous insulin injections several times a day. In type 2 diabetes, characterized by insulin resistance and abnormal insulin secretion, the patients need exercise, diet control and/or several types of hypoglycemics. The idea of using metal ions for the treatment of diabetes originates from the report in 1899. The research on the role of metal ions that may contribute to the improvement of diabetes began. The orally active metal complexes containing vanadyl (oxidovanadium(iv)) ion and cysteine or other ligands were first proposed in 1990, and a wide class of vanadium, copper and zinc complexes was found to be effective for treating diabetes in experimental animals. We noticed a characteristic compound, allixin, which is a non-sulfur component in dry garlic. Its vanadyl and zinc complexes improved both types of diabetes following oral administration in diabetic animals. We then developed a new zinc complex with thioxoallixin-N-methyl (tanm), which is both a sulfur and N-methyl derivative of allixin, and found that this complex improves not only diabetes but also metabolic syndrome. Furthermore, new zinc complexes inspired from the zinc-tanm were prepared; one of them exceeded the activity of zinc-tanm. The mechanism of such complexes was studied in adipocytes. We describe here the usefulness of the development of metal-based complexes in the context of potential therapeutic application for diabetes and metabolic syndrome.

Inhibitory effect of CuSO4 on α-glucosidase activity in ddY mice.

We investigated the effects of divalent alkaline earth and first-row transition metal and zinc ions on α-glucosidase activity in vitro and in vivo. CuSO4 and ZnSO4 exhibited a high α-glucosidase inhibitory effect in vitro. The IC(50) values of CuSO4 were 0.77 ± 0.01 (substrate; maltose) and 0.78 ± 0.01 (substrate; sucrose), and those of ZnSO4 were 5.49 ± 0.14 (substrate; maltose) and 4.70 ± 0.06 (substrate; sucrose) for yeast α-glucosidase. On the basis of Lineweaver-Burk plots, both CuSO4 and ZnSO4 exhibited different modes of inhibition against α-glucosidase. Subsequently, oral glucose and sucrose tolerance tests (OGTT and OSTT) were performed on non-diabetic ddY mice to examine the effect of the metal ions on their blood glucose levels. As a result of single oral administration of CuSO4 in non-diabetic ddY mice, a significant and potent lowering of the blood glycemic response toward disaccharide, sucrose, ingestion was observed at 45 min after doses of 0.08 and 0.24 mmol kg(-1) body weight. In contrast, the CuSO4 administration showed no suppression of the elevation of blood glucose levels in mice after a monosaccharide, glucose, administration. These results indicate that CuSO4 suppresses disaccharide digestion by inhibiting α-glucosidase activity in the epithelium of the small intestine, suggesting that antidiabetic Cu complexes with some ligands have a similar action mechanism to that of α-glucosidase inhibitor, acarbose, currently used for clinical purposes.

Complexes of hydroxy(thio)pyrone and hydroxy(thio)pyridinone with Zn(II) and Mo(VI). Thermodynamic stability and insulin-mimetic activity.

The development of metal-containing pharmaceuticals as insulin-mimetics has been the object of recent worldwide research. We have examined a series of zinc(II) and molybdenum(VI) complexes with model O,S-donor ligands (thiomaltol and 1,2-dimethyl-3-hydroxypyridine-4-thione (DMHTP)) and the corresponding O,O-analogues (maltol and DMHP) for their insulin-mimetic activity. Aimed at getting structure-activity relationships, some physical-chemical properties were also studied, such as metal-complex formation, speciation at different pH conditions and ligand lipophilicity. The Zn-complexes exhibit considerably higher insulin-mimetic activity than the corresponding Mo-analogues. Particularly, the bis(thiomaltolato)zinc(II) complex reveals a very high activity, ascribed to the effect of the thione π character and to the soft nature of the sulfur donor atom enhancing the Zn(II)-ligand affinity and the ligand/complex lipophilicity, two determinant parameters for delivering the metal-drug into the cells. Hence, these preliminary studies indicate that the Zn(thiomaltol)2 complex can be considered a potential drug candidate for treatment of diabetes mellitus, upon in vivo evaluations.

Bis- and tris(pyridyl)amine-oxidovanadium complexes: characteristics and insulin-mimetic potential.

Two novel vanadium complexes, [V(IV)O(bp-O)(HSO4)] (1) and [V(IV)O(bp-OH)Cl2] x CH3OH (2 x CH3OH), where bp-OH is 2-{[bis(pyrid-2-yl)methyl]amine}methylphenol, were prepared and structurally characterised. EPR spectra of methanol solutions of 2 suggest exchange of Cl- for CH3OH and partial conversion to [VO(bp-OH)(CH3OH)3]2+. Speciation studies on the VO2+-bpOH system in a water/dmso mixture (4:1 v/v) revealed [VO(bp-O)(H2O)n]+ as the dominating species in the pH range 2-7. The insulin-mimetic properties of 1 and 2, [V(IV)O(SO4)tpa] (3), [V(IV)O(pic-trpMe)2] (5) and the new mixed-ligand complexes [V(V)O(pic-trpH)tpa]Cl2 (4Cl2) and [V(V)O(pic-OEt)tpa]Cl2 (6Cl2), tpa = tris(pyrid-2-yl)methylamine, picH-trpH = 2-carboxypyridine-5-(L-tryptophan)carboxamide (picH-trpMe is the respective tryptophanmethyl ester), pic-OEt = 5-carboethoxypyridine-2-carboxylic acid, were evaluated with rat adipocytes, employing two lipolysis assays (release of glycerol and free fatty acids (FFA)), respectively and a lipogenesis assay (incorporation of glucose into lipids). The IC50 values for the inhibition of lipolysis in the FFA assay vary between 0.41 (+/-0.03) (5) and 21.2 (+/-0.6) mM (2), as compared to 0.81 (+/-0.2) mM for VOSO4.

Sampling nanoparticles for chemical analysis by low resolution electrical mobility classification.

The use of electrostatic classification to collect samples of aerosol nanoparticles for chemical analysis is discussed. Our technique exposes the aerosol to negative ions in a unipolar charger with subsequent mobility classification at low resolution and high sampling rate. The negative unipolar charger produces high charged fractions. The low-resolution mobility classifier enables the delivery of high mass concentrations in a well-defined mobility range. The mobility-classified particles are collected by electrostatic precipitation. We summarize experimental and computational work on the performance of the unipolar charger, and we describe the performance of the overall system when used to sample atmospheric particles. For a size distribution measured in Atlanta during a new particle formation event, calculated mass sampling rates of approximately 8 nm particles were about 150 pg/h.