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PubMed1983

o-Phthaldialdehyde precolumn derivatization and reversed-phase high-performance liquid chromatography of polypeptide hydrolysates and physiological fluids.

A rapid and ultrasensitive fluorescence amino acid analysis system has been developed which utilizes omicron-phthaldialdehyde as a precolumn derivatizing agent. omicron-Phthaldialdehyde in the presence of mercaptan reacts rapidly with primary amino acids to form intensely fluorescent derivatives. These derivatives are analyzed with good selectivity by high-performance liquid chromatography employing 3-microns particle size reversed-phase columns. Resolution of the amino acid derivatives is accomplished with a methanol gradient in 0.1 M aqueous sodium acetate, pH 7.2. The quantitation of the individual amino acid derivatives is reproducible within an average relative deviation of +/- 1.5% and has a detection limit of less than 100 fmoles. Amino acid mixtures obtained by either enzymatic or acid hydrolysis of polypeptides are efficiently resolved with an analysis time of less than 18 min. Methods for the amino acid analysis of physiological fluids such as serum, urine and cerebrospinal fluid were also developed which employ the above separation procedure for the identification and quantitation of amino acids and other biological amines. Mixtures which contained as many as 48 components were resolved with an analysis time of less than 50 min.

Aldehydes↗
PubMed2000

Effects of hemoglobin-based oxygen-carrying solutions in anesthetized rats with acute ischemic renal failure.

The effects of three hemoglobin solutions were compared with those of iso-oncotic human serum albumin in rats with ischemic renal failure and sham-operated controls. Unmodified and alpha-alpha cross-linked hemoglobins both increase mean arterial pressure and systemic vascular resistance and reduce cardiac output substantially and to a comparable extent. In contrast, omicron-raffinose cross-linked hemoglobin has no deleterious effect on any of these parameters. In sham-operated rats unmodified hemoglobin reduces the glomerular filtration rate (GFR) by approximately 30%, whereas neither of the two cross-linked hemoglobins has any adverse effect on GFR in this group. None of the three hemoglobin solutions exacerbated the degree to which GFR was reduced by ischemia-reperfusion injury. Also, the degree of tubular necrosis induced by ischemia-reperfusion injury was also comparable in all groups. We conclude the following: (1) omicron-raffinose cross-linking, but not alpha-alpha cross-linking, ameliorates the effects of unmodified hemoglobin on vascular resistance and cardiac output; (2) both forms of cross-linking reduce the nephrotoxicity exhibited by unmodified hemoglobin in sham-operated rats; and (3) none of the hemoglobin solutions exacerbate renal injury induced by ischemia-reperfusion.

Acute Kidney Injury↗
PubMed1996

Triterpenoid saponins from Herniaria fontanesii.

Two new saponins have been isolated from the aerial parts of Herniaria fontanesii. Their structures were established as 28-O-[alpha-L-rhamnopyranosyl-(1-->2-[(alpha-L- rhamnopyranosyl)-(1-->3)-]-(beta-D-4-acetoxyfucopyranosyl] ester of 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl uronic]-2 beta-3 beta-16-alpha-trihydroxy-olean-12-ene-23, 28-dioic acid and 28-omicron-[alpha-L-rhamnopyranosyl-(1-->2-[alpha-L-rhamnopyranosyl (1-->3)]-(beta-D-fucopyranosyl] ester of 3-omicron-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl uronic]-2 beta-3 beta-16-alpha-trihydroxy-olean-12-ene-23, 28 dioic acid.

Carbohydrate Sequence↗
PubMed1996

Two flavonol triglycosides from flowers of Indigofera hebepetala.

Two new flavonol triglycosides, kaempferol 3-omicron-alpha-L-rhamnopyranosyl(1->2)-beta-D-galactopyranoside-7-O- alpha-L-arabinofuranoside and kaempferol 3-O-alpha-rhamnopyranosyl(1-->6)-beta-D-galactopyranoside-7-O- alpha-L-arabinofuranoside were isolated from the flowers of Indigofera hepepetala, together with three known glycosides, kaempferol 3-omicron-alpha-L-arabinopyranoside-7-O-alpha-L-rhamnopyranoside, kaempferol 3-O-alpha-L-rhamnopyranoside-7-O-alpha-L-arabinopyranoside and kaempferol 7-rhamnoside. The structures were determined by means of Rf values, UV, EI-mass spectrometry, FAB-mass spectrometry, 1H NMR, 13C (B.B and DEPT) NMR, NOE difference measurement and 1H-1H COSY spectral data.

Flavonoids↗
PubMed1975

A new approach to the study of phospholipid-protein interactions in biological membranes. Synthesis of fatty acids and phospholipids containing photosensitive groups.

In a general approach to the study, in vivo and in vitro, of the interactions between phospholipids and proteins in biological membranes, a variety of fatty acids containing photosensitive groups in different positions in the alkyl chains has been synthesized. The fatty acids synthesized include: 16-azidopalmitelaidic acid, 12-azidooleic acid, 6-, 9-, 11-, and 12-azidostearic acid, 12-omicron-(ethyl-2-diazomalonyl)stearic and -oleic acids, 12-omicron-(4-azido-2-nitrophenyl)stearic and -oleic acids, and 12-oxo-10-octadecenoic acid. Some of the above synthetic fatty acids were also prepared in the radioactively labeled form. For in vitro studies, many of the above fatty acids were used to acylate the 2 position in the preparation of a number of mixed acylphosphatidylcholines and mixed acylphosphatidylethanolamines. On sonication, the synthetic phospholipids formed sealed vesicles. Intermolecular cross-linking of the fatty acyl chains in phospholipids was demonstrated on photolysis of the vesicles.

Fatty Acids↗
PubMed2002

Charge transfer of iron(III) monomeric and oligomeric aqua hydroxo complexes: semiempirical investigation into photoactivity.

Aqueous hydrolyses of iron(III) solutions were studied using electronic spectroscopy. Complete spectra from 200 to 800 nm were obtained for the four ferric aqua hydroxo complexes: Fe(H(2)O)(6)(3+), Fe(OH)(H(2)O)(5)(2+), Fe(OH)(2)(H(2)O)(4)(+), and the dimer Fe(2)(mu-Omicron Eta)(2)(H(2)O)(8)(4+). Semiempirical Zindo/s calculations were employed to assign which types of electronic transfers are involved so that the photoactivity as regards the photoreduction dissociation Fe(III)(aq) Fe(II)(aq) + OH* can be discussed. Fe(3+) exhibits two LMCT from non-bonding p orbitals (nLp) located at 190 and 240 nm. Fe(OH)(2+) shows two major nLp(OH) --> d transitions at 205 and 295 nm. As regards its geometry, computed investigations using an Fe-OH distance of 2.05 A better fit than using a shorter distance ( approximately 1.8 A); the same conclusion remains constant for all hydroxo complexes. The dihydroxo form's spectrum was confronted to its common cis and trans expectable isomers plus an unusual pentacoordinate one. Even if the trans isomer is supposed to be the lowest Gibbs free energy species in solution, there is some evidence of the presence of the cis form; hence, both species must be close in energy. Other isolated nLp(OH) --> d transfer wavelengths are 235, 245, and 335 nm. As for the dimer, this study provides some clue in favor of the bis(mu-hydroxo)) description. Both water and hydroxo ligands are involved along the electronic transitions toward only d(1) metal-centered orbitals at 220 and 260 nm for H(2)O, 335 and 470 nm for OH(-), and 205 nm for both. Charge transfers for the hydrogen oxide bridge form Fe(2)(mu-Eta(3)Omicron(2))(H(2)O)(8)(5+) were also computed. Finally predictions about the two bis(mu-hydroxo) bridge trimer Fe(3)(OH)(4)(H(2)O)(10)(5+) enable one to foresee a huge and broad charge transfer in the UV region (approximately 240 nm) followed by a multi nLp(OH) --> d(1) transfer extending up to approximately 650 nm.

Journal Article↗
PubMed2003

New vanadium phosphate ([(phen)VIVO]2(VV2O5)(HPO4))n with chiral layer architecture.

A new layered vanadium phosphate ([(phen)V(IV)O](2)(V(V)(2)O(5))(HPO(4))n has been hydrothermally synthesized and structurally characterized by elemental analysis, IR, and single-crystal X-ray diffraction. This compound crystallized in the monoclinic space group P2/c with a = 9.979(2) A, b = 9.886(2) A, c = 15.298(3) A, beta = 102.86(3) degrees, V = 1471.3(5) A(3), and Z = 4. In the structure of this compound, two nitrogen atoms of 1,10-phen are directly coordinated to the vanadium skeleton. Interestingly, the crystal structure consists of two types of chiral layers, one left-handed and the other right-handed, which lead to a racemic solid-state compound. In each layer, there coexist three distinct rings, described as a 8-membered ring [V(2)(oct)P(2)O(4)], 12-membered ring [V(2)(omicron)(ct)V(2)(tet)P(2)O(6)], and 16-membered ring [V(2)(omicron)(ct)V(4)(tet)P(2)O(8)].

Journal Article↗
PubMed2002

How does internal motion influence the relaxation of the water protons in Ln(III)DOTA-like complexes?

Taking advantage of the Curie contribution to the relaxation of the protons in the Tb(III) complex, and the quadrupolar relaxation of the 17O and 2H nuclei on the Eu(III) complex, the effect of the internal motion of the water molecule bound to [Ln(DOTAM)(H2O)]3+ complexes was quantified. The determination of the quadrupolar coupling constant of the bound water oxygen chi(Omicron)(1 + eta(Omicron)2/3)1/2 = 5.2 +/- 0.5 MHz allows a new analysis of the 17O and 1H NMR data of the [Gd(DOTA)(H2O)]- complex with different rotational correlation times for the Gd(III)-O(water) and Gd(III)-H(water) vectors. The ratio of the rotational correlation times for the Ln(III)-H(water) vector and the overall rotational correlation time is calculated tau(RH)/tau(RO) = 0.65 +/- 0.2. This could have negative consequences on the water proton relaxivity, which we discuss in particular for macromolecular systems. It appears that the final effect is actually attenuated and should be around 10% for such large systems undergoing local motion of the chelating groups.

Journal Article↗
PubMed1975

Structure-activity correlations among rifamycin B amides and hydrazides.

Structure-antibacterial activity correlation equations have been developed for aseries of 44 amides and 25 hydrazides of rifamycin B in five bacterial systems. The best amide equations show that activity is a parabolic function of log P. A wide variation in log Po was found for the various bacterial systems. The most important correlation parameter in the hydrazide equations is omicron*. The significance of this finding is somewhat obscured by the high degree of collinearity among the parameters evaluated (omicron*, E-s, log P). Two rifamycin B amides were prepared and evaluated as a result of this study. The correlation equations quantitatively predicted their activity in five of six tests.

Amides↗
PubMed2026

Clinical and genomic characterization of Influenza A co-infection with SARS-CoV-2 and Influenza B: a respiratory surveillance study in Assam, India.

Influenza and SARS-CoV-2 are the primary contributors to seasonal respiratory infections and frequently co-circulate, creating significant health challenges. The present respiratory surveillance study was conducted in Dibrugarh, Assam, India from January 2025 to August 2025 to investigate the genomic characteristics of circulating viruses and identify potential co-infections. Overall, 4,948 respiratory samples were screened using multiplex real-time PCR, followed by subtyping of Influenza A and Influenza B. Next-generation sequencing (NGS) was performed in selected positives of SARS-CoV-2 and Influenza A. Genomic analysis included mutational profiling, phylogenetic analysis and N-glycosylation site prediction using bioinformatics tools. Two co-infection cases were detected: one involving Influenza A (H3N2) with SARS-CoV-2 (Omicron XFG lineage) and another involving Influenza A (H3N2) with Influenza B (Victoria lineage). Both patients experienced mild illness without hospitalisation. NGS revealed that the Influenza A (H3N2) viruses belonged to clade 3C.2a1b.2a.2a.3a.1 while SARS-CoV-2 sequence was classified under the Omicron XFG lineage. Mutational analysis of the HA gene showed several amino acid differences compared to the reference vaccine strain A/Darwin/6/2021. N-glycosylation analysis predicted conserved sites at positions 79, 181, 262, and 301 in all strains along with an additional predicted site at position 110 in both co-infection cases. Although the co-infection cases presented with mild clinical manifestations, the observed genomic variations indicate a potential role of co-infecting viruses in shaping viral evolution. Given the limited genomic data available from Northeast India, the study underscores the need for sustained large scale follow up and genomic surveillance to monitor emerging mutations and target future vaccine strategies.

Humans↗
PubMed1975

Multiple effects of calcium antagonists on plateau currents in cardiac Purkinje fibers.

We studied the influence of Mn, La, and D600 on action potentials and plateau currents in cardiac Purkinje fibers. The Ca antagonists each abolished the second inward current, but they failed to act selectively. Voltage clamp experiments revealed two additional effects: decrease of slow outward current (iotachi) activation, and increase of net outward time-independent plateau current. These effects occurred at inhibitor concentrations used in earlier studies, and were essential to the reconstruction of observed Ca antagonist effects on electrical activity. The inhibitory influence of Mn, La, and D600 on iotachi suggested that iotachi activation might depend upon prior Ca entry. This hypothesis was not supported, however, when [Ca]omicron was varied: elevating [Ca]omicron enhanced Ca entry, but iotachi was nevertheless depressed. Thus, the results suggested instead that Ca antagonists and Ca ions have rather similar effects on iotachi, possibly mediated by changes in membrane surface charge.

Action Potentials↗
PubMed2005

An efficient algorithm for sorting by block-interchanges and its application to the evolution of vibrio species.

In the study of genome rearrangement, the block-interchanges have been proposed recently as a new kind of global rearrangement events affecting a genome by swapping two nonintersecting segments of any length. The so-called block-interchange distance problem, which is equivalent to the sorting-by-block-interchange problem, is to find a minimum series of block-interchanges for transforming one chromosome into another. In this paper, we study this problem by considering the circular chromosomes and propose a Omicron(deltan) time algorithm for solving it by making use of permutation groups in algebra, where n is the length of the circular chromosome and delta is the minimum number of block-interchanges required for the transformation, which can be calculated in Omicron(n) time in advance. Moreover, we obtain analogous results by extending our algorithm to linear chromosomes. Finally, we have implemented our algorithm and applied it to the circular genomic sequences of three human vibrio pathogens for predicting their evolutionary relationships. Consequently, our experimental results coincide with the previous ones obtained by others using a different comparative genomics approach, which implies that the block-interchange events seem to play a significant role in the evolution of vibrio species.

Algorithms↗
PubMed1986

A Zn2+-dependent and histone H1-specific protease in sea urchin sperm.

Protease activity was extracted from sea urchin sperm with 1% Triton X-100 and partially purified by DEAE-cellulose and Sephadex G-100 chromatography. The enzyme preferentially degraded histone H1, while showing only a weak activity toward other histones. Heat-denatured casein and bovine serum albumin were not digested by this enzyme under the present experimental conditions. This protease hydrolyzed only Boc-Val-Leu-Lys-MCA among various peptidyl-MCAs. The optimal pH ranged from 7 to 11. Its molecular weight was about 41,000. Among various known inhibitors of proteases, only omicron-phenanthroline effectively inhibited the activity. The enzyme was stimulated by Zn2+ or Co2+. It was inactivated by omicron-phenanthroline but could be reactivated by the addition of Zn2+ or Co2+. Therefore, this protease seems to be a metalloprotease dependent on Zn2+ or Co2+. The insensitivity of this enzyme to phosphoramidon and its very restricted substrate specificity suggest that this enzyme is very different from other metalloproteases described hitherto.

Animals↗
PubMed1985

Cytochrome P450: substrate and prosthetic-group free radicals generated during the enzymatic cycle.

During the enzymatic cycle of the cytochromes P450, dioxygen binds to the ferrous haemprotein when the resting ferric haemprotein has undergone a one-electron oxidation after substrate binding. A further one-electron reduction generates an intermediate that is isoelectronic with a peroxide dianion coordinated to a ferric iron. Heterolytic cleavage of the omicron--omicron bond generates water and a species which is formally an oxene (oxygen atom) coordinated by iron(III). However, on the basis of model reactions and by analogy to the catalases and peroxidases, this active oxidizing intermediate is formulated as an oxo-FeIV porphyrin pi-cation radical. The radical is stabilized by delocalization on the porphyrin macrocycle and the high oxidation state is achieved by oxidizing both the metal and the porphyrin ring of the haemprotein. Hydrogen atom abstraction from a saturated hydrocarbon substrate generates a substrate free radical, constrained by the protein binding site, and the equivalent of a hydroxyl radical bound to iron(III). Coupling of the 'hydroxy' and substrate radicals generates hydroxylated product and resting protein. For olefins an initial electron transfer to oxidized haemprotein gives a substrate cation radical. Further reaction of this radical can give the epoxide, the principal product; an aldehyde or ketone by rearrangement; or an alkylated haemprotein resulting in suicide inhibition.

Catalase↗
PubMed2006

Displacement- and timing-noise-free gravitational-wave detection.

Motivated by a recently invented scheme of displacement-noise-free gravitational-wave detection, we demonstrate the existence of gravitational-wave detection schemes insusceptible to both displacement and timing (laser) noises and are thus realizable by shot-noise-limited laser interferometry. This is possible due to two reasons: first, gravitational waves and displacement disturbances contribute to light propagation times in different manners; second, for an N-detector system, the number of signal channels is of the order Omicron(N(2)), while the total number of timing- and displacement-noise channels is of the order Omicron(N).

Journal Article↗
PubMed1976

Alterations in resting membrane properties during neural plate stages of development of the nervous system.

1. The mean resting membrane potential of cells in the neural plate of axolotl embryos increases from -25 to -45 mV (maximum values from -35 to -60 mV) when the embryos move from early to mid-neural plate stages of development. 2. Increasing the extracellular [K] to 20 mM shortly before the spontaneous increase in resting potential occurs causes neural plate cells to hyperpolarize. 3. A moderate increase in [K]omicron does not hyperpolarize the membrane of neural plate cells at earlier stages or at late neural fold stages. 4. Both the hyperpolarization produced by K and the normal increase in resting potential are blocked by cardiac glycosides. 5. Cells of the ventral ectoderm do not display an increase in resting potential during the neural fold stages of development and do not hyperpolarize in response to a moderate increase in [K]omicron. 6. The results suggest that activation of the Na pump may be an early consequence of neural induction. They are discussed in the light of this suggestion.

Ambystoma↗
PubMed1975

"Killer" character does not influence the transmission of mitochondrial genes in Saccharomyces cerevisiae.

Three cytoplasmic genetic elements have been shown to be separate from mitochondrial deoxyribonucleic acid (DNA), [rho], in Saccharomyces cerevisiae: the killer character [k], omicron-DNA, and psi [psi]. Griffiths has suggested genetic interactions between [VENR] and [TETR] mutants possibly located on omicron-DNA and mitochondrial genetic markers, but possible interactions between the best characterized of the three, the killer character, and mitochondrial DNA have not been investigated. To test this we isolated cycloheximide-induced nonkiller segregants (NKS) of killer cells with suitable genetic markers and mated them in [k] x [k], [k] x [k], and (NKS) x (NKS) combinations. No differences in quantitative mitochondrial marker transmission between these groups were found in crosses illustrating the mitochondrial phenomena of bias, polarity, and suppressiveness. Our studies show that no intercellular interactions between [k] and (NKS) cells influence mitochondrial transmission genetics. Intracellular interactions between the smaller double-stranded ribonucleic acid of [k] and mitochondrial DNA also were not detected.

Chloramphenicol↗
PubMed1997

Diseases in the Byzantine world with special emphasis on the nephropathies.

Using medical manuscripts and texts from the Byzantine period (330-1453), this article describes various, to date little discussed, aspects of Byzantine nosology, public health and therapeutics. Many diseases in the Byzantine era were widespread and had a high morbidity such as respiratory disease, various kinds of anaemia, pestilential diseases (e.g. quartan fever, plague, dysentery and cholera), parasitic diseases, orthopaedic, rheumatic and psychiatric disorders, trachoma and alcoholism. Other very serious and relatively frequent conditions included leprosy, mania, gout, cancerous tumours and ulcers. Important elements of nephrology and various renal diseases were described and investigated, such as acute and chronic renal failure, acute and chronic nephritis, pyelonephritis, necrotic renal diseases, crush syndrome, and ulcers of the kidneys, i.e. tuberculosis or renal tumours. The microhistology and physiology of the kidneys were first studied by Oribasius, who discerned the existence of the capillaries--tau rho iota chi omicron epsilon iota delta eta--some centuries before Malpighi. He also correctly described the blood circulation, general and pulmonary, as a precursor to Harvey. The first hospitals were organised during the Byzantine period, and the practice of Byzantine medical science and its social applications were regulated by a special medical legislation and deontology. Byzantine medicine was fruitfully connected with the Christian faith and developed the supreme model of the saints unmercenary--alpha nu alpha rho gamma epsilon rho omicron iota--physicians such as Cosmas and Damian (3rd century), Panteleemon (3rd-4th centuries) and the women physicians and miracle-worker saints, Zenais and Philonilla (1st century), the 'friends of peace', and Hermione (1st-2nd centuries).

Byzantium↗