Restoration of photosystem II photochemistry and carbon assimilation and related changes in chlorophyll and protein contents during the rehydration of desiccated Xerophyta scabrida leaves.

Recovery of photosynthesis in rehydrating desiccated leaves of the poikilochlorophyllous desiccation-tolerant plant Xerophyta scabrida was investigated. Detached leaves were remoistened under 12 h light/dark cycles for 96 h. Water, chlorophyll (Chl), and protein contents, Chl fluorescence, photosynthesis-CO(2) concentration response, and the amount and activity of Rubisco were measured at intervals during the rehydration period. Leaf relative water contents reached 87% in 12 h and full turgor in 96 h. Chl synthesis was slower before than after 24 h, and Chla:Chlb ratios changed from 0.13 to 2.6 in 48 h. The maximum quantum efficiency recovered faster during rehydration than the photosystem II operating efficiency and the efficiency factor, which is known to depend mainly on the use of the electron transport chain products. From 24 h to 96 h of rehydration, net carbon fixation was Rubisco limited, rather than electron transport limited. Total Rubisco activity increased during rehydration more than the Rubisco protein content. Desiccated leaves contained, in a close to functional state, more than half the amount of the Rubisco protein present in rehydrated leaves. The results suggest that in X. scabrida leaves Rubisco adopts a special, protective conformation and recovers its activity during rehydration through modifications in redox status.

Atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) in mosses (Hypnum cupressiforme) in Hungary.

The atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) was investigated in Hungary by analyzing a moss (Hypnum cupressiforme) species as a bioindicator. In the autumn of 1997, samples were collected at 29 sites distributed across Hungary. The concentrations of total PAH at these sites were in the range of 0.1567-10.45 x 10(4) microg kg(-1) with a mean value of 1.87 x 10(4) microg kg(-1). More than 99% of the total PAHs atmospheric deposition were low molecular weight PAHs (up to 3 ring compounds). The total PAH values showed no correlation with metal concentrations. However, most of the sites in this region showed a positive linear relationship between PAHs levels and traffic volume (r2 = 0.83; P < 0.001) while no relationship existed between PAH levels and population (r2 = 0.01; P > 0.1). Atmospheric deposition of PAHs at different regions in Hungary may be due to incomplete combustion of fuel. The total concentrations of PAHs were compared to the PAH levels in vegetation samples collected from different regions around the world. The highest PAHs concentrations accumulated were found in Hypnum cupressiforme than other vegetation species. A greater affinity for PAH compounds by Hypnum cupressiforme than other moss species probably caused larger amounts of accumulation. A relationship between accumulations of PAH compounds in Hypnum cupressiforme and octanol-air partition coefficients was obtained and is briefly discussed.

First national survey of atmospheric heavy metal deposition in Hungary by the analysis of mosses.

The atmospheric deposition of Cd, Cr, Cu, Fe, Ni, Pb, V and Zn in Hungary was investigated by using moss species as bioindicators. Our research was part of an international mapping project (Atmospheric Heavy Metal Deposition in Europe) [NORD 21 (1987) 1-44; NORD 9 (1994)] carried out in the most European countries in the 1990s to determine and to compare atmospheric heavy metal background pollution by standardized methods. Sampling was performed at 116 sites distributed over Hungary in the autumn of 1997. Moss species of Hypnum cupressiforme (72.4%) were preferred. But where it could not be collected, other species were taken. Unwashed, dried samples were digested with H(2)O(2)/HNO(3), and the concentrations of heavy metals were determined by ICP-AES. The results reflect local emission points. Background mean levels of Cd, Fe and Ni were mildly elevated in comparison to European means [NORD 9 (1994)]. Probably, that was due not only to pollution, but to the use of Hypnum cupressiforme, which can accumulate higher concentrations of heavy metals compared to other species. The results are presented on colored contour maps obtained with the SURFER program (Golden Software Inc. Co).

A new short-acting non-depolarizing muscle relaxant (SZ1677) without cardiovascular side-effects.

BACKGROUND: In order to facilitate rapid tracheal intubation, the development of a rapid onset, short duration, non-depolarizing muscle relaxant without cardiovascular side-effects would be a significant accomplishment in the field of anesthesiology. The aim of the present study was to test the action of a new non-depolarizing muscle relaxant (SZ1677) on neuromuscular transmission, muscarinic (M2, M3) receptors and cardiovascular reactions and to compare it with clinically used muscle relaxants. METHODS: Neuromuscular transmission was studied by recording muscle contractions elicited by indirect electrical stimulation, using (i). in vitro isolated phrenic nerve-hemidiaphragm preparation of mice, rats and guinea pigs and (ii). in vivo sciatic nerve-anterior tibial muscle preparation of anesthetized rats, guinea pigs and cats. Cardiovascular effects of muscle relaxants were evaluated on the grounds of their effects on changes of blood pressure and heart rate induced by electrical stimulation of the right vagal nerve in anesthetized cats. To study postsynaptic antimuscarinic affinity of muscle relaxants on M3 receptors, oxotremorine-induced contractions of longitudinal muscle strip of guinea pig ileum were registered in their presence and absence. RESULTS: One of more than 120 newly synthesized non-depolarizing muscle relaxants compounds, 1-3[alpha-hydroxy-17beta-acetyloxy-2beta-(1,4-dioxa-8-azaspiro[4,5]dec-8-yl)-5alpha-androstane-16beta-il] -1-(2-propenyl)pyrrolidinium bromide (SZ1677), excelled with its advantageous pharmacological properties: relatively short duration of action, no accumulation and lack of unwanted side-effects. Pharmacodynamic studies show that SZ1677 is a non-depolarizing neuromuscular blocking agent with a relatively short duration and rapid onset of action in a variety of laboratory animal species. It is without cumulative effect, does not reduce blood pressure, and fails to produce tachycardia. Significant cardiac vagal blocking effects were not observed even at concentrations or dosages of 8 times the ED90. This compound, unlike many other muscle relaxants, does not have atropine-like effects on human atrial tissue; it does not increase the release of NA from sympathetic innervation in the heart. In all practical ways, at least from the vantage point of the preclinical study, SZ1677 compares favorably with all presently available short-acting muscle relaxants, including rapacuronium. CONCLUSION: In experiments, SZ1677 proved to be a short-acting neuromuscular blocking compound having a large safety margin between the doses required to produce neuromuscular block and those likely to lead to cardiovascular side-effects.

Synthesis and biological activity of a new progestogen, 16-methylene-17alpha-hydroxy-18-methyl-19-norpregn-4-ene-3, 20-dione acetate.

The progestational activity of second- and third-generation progestins in oral contraceptives were markedly increased by addition of an 18-methyl group. A new progestin, the 18-methyl analog of Nestorone, 16-methylene-17alpha-hydroxy-18-methyl-19-norpregn-4-ene-3,2 0-dione acetate (10), was synthesized. The relative binding affinity and biologic activity of 10 was compared with Nestorone, levonorgestrel, and progesterone using a binding assay for rat progesterone receptors, the Clauberg assay in the rabbit, and by assessing pregnancy maintenance in the rat. These studies, as summarized in Table 4, show that 10 is three to ten times more potent than Nestorone. The addition of the 18-methyl group to Nestorone markedly increased its potency as noted above, but is unlikely to change its rate of delivery from sustained release systems. 10 should be ideally suited for administration by implants or small skin patches.

[Tandem MS/MS combined with different ionization techniques in the study of steroid structures]. / Szteroidok tömegspektrometriás szerkezetvizsgálata különbözó ionizációs módszerek és MS/MS technikák kombinált alkalmazásával.

The various mass spectrometric ionisation techniques involve different ionisation energy. Their parallel application may provide complementary information for the structure. By the use of soft ionisation methods, especially when combined with tandem mass spectrometric techniques, stereospecific dissociation can also be detected, as the fragmentation processes of low energy differences result in significant abundance differences. The EI spectra of the stereoisomer compounds 1 and 2 are compared to their FAB-daughter ion spectra. This latter method leads to higher differences in the water elimination, indicating that the beta-hydroxi-isomer is more stable. ESI studies, using the "in-source CID" technique and also combined with MS/MS investigation have provided direct information about the position of substituents for the bis-quaternary salts of amino androstane derivatives, pipecuromium bromide [ARDUAN (3)] and its related compound 4. Due to the complementary information of the different ionisation methods used in mass spectrometry, the exact and detailed structural study requires the combined application of the various ionisation techniques together with MS/MS methods.

Heck reactions of steroidal alkenyl iodides.

Heck reactions of some steroid derivatives possessing iodo-alkenyl moiety (17-iodo-androst-16-ene, 1, 17-iodo-4-aza-4-methyl-androst-16-en-3-one, 2, 17-iodo-4-aza-androst-16-en-3-one, 3) were carried out in the presence of palladium catalysts using various olefins (methyl acrylate, ethyl methacrylate, allyl alcohol and allyl acetate) as coupling partners. With methyl acrylate, a side reaction was observed: the coupling product underwent a Diels-Alder reaction with the excess of methyl acrylate resulting in a six-membered carbocyclic E-ring. Reaction conditions of the synthesis of the Heck-product were optimized. Although the coupling with allyl alcohol led to the formation of 21-formyl-16-pregnene derivatives, the synthesis of the corresponding steroidal unsaturated alcohol could be achieved only via hydrolysis of the coupling product of the alkenyl iodide with allyl acetate.

Estimation of impurity profiles of drugs and related materials Part 18. Impurities and degradation products of mazipredone.

Reversed-phase HPLC methods using C-18 and C-8 columns as well as various isocratic and gradient systems with aqueous ammonium acetate, methanol and acetonitrile are described for the separation of the impurities of mazipredone (11beta,17-dihydroxy-21-(4-methyl-1-piperazinyl)-pregna-1,4-diene- 3,20-dione hydrochloride). These methods were used also for the estimation of the hydrolytic and oxidative degradation pathways of mazipredone in 0.1 M hydrochloric acid and sodium hydroxide at 80 degrees C. With the aid of HPLC-(APCI)-MS and HPLC-diode-array UV techniques 15 impurities and degradation products have been identified.

Thermoluminescence studies on the function of Photosystem II in the desiccation tolerant lichen Cladonia convoluta.

The effect of desiccation and rehydration on the function of Photosystem II has been studied in the desiccation tolerant lichen Cladonia convoluta by thermoluminescence. We have shown that in functional fully hydrated thalli thermoluminescence signals can be observed from the recombination of the S2(3)QB (-) (B band), S2QA (-) (Q band), Tyr-D(+)QA (-) (C band) and Tyr-Z(+)(His(+))QA (-) (A band) charge stabilization states. These thermoluminescence signals are completely absent in desiccated thalli, but rapidly reappear on rehydration. Flash-induced oscillation in the amplitude of the thermoluminescence band from the S2(3)QB (-) recombination shows the usual pattern with maxima after 2 and 6 flashes when rehydration takes place in light. However, after rehydration in complete darkness, there is no thermoluminescence emission after the 1 st flash, and the maxima of the subsequent oscillation are shifted to the 3rd and 7th flashes. It is concluded that desiccation of Cladonia convoluta converts PS II into a nonfunctional state. This state is characterized by the lack of stable charge separation and recombination, as well as by a one-electron reduction of the water-oxidizing complex. Restoration of PS II function during rehydration can proceed both in the light and in darkness. After rehydration in the dark, the first charge separation act is utilized in restoring the usual oxidation state of the water-oxidizing comples.

Homogeneous catalytic dehalodimerization of 17-iodo-delta 16 steroids.

17-Iodo-delta 16 steroids undergo selective dimerization and carbonylative dimerization in the presence of palladium catalysts in dimethylformamide which result in 16-17'-coupled dienes and 17-carboxylic anhydrides, respectively. Moderate to good yields have been obtained for both types of dimers.

Steroidal alkenylphosphonates via palladium-catalyzed coupling reactions.

The palladium-catalyzed coupling of various 17-iodo-delta 16 steroids (17-iodo-androst-16-ene, 17-iodo-4-methyl-4-aza-androst-16-en-3-one, and 17-iodo-4-aza-androst-16-en-3-one) with dialkyl phosphites (dimethyl phosphite, diethyl phosphite, and diisopropyl phosphite) was examined in detail. The only successful condition for homogeneous coupling involved carrying out the reaction in the absence of any solvents. A large excess of dialkyl phosphite was used, which means that the phosphite itself acted as a solvent. Eight new androst-16-ene derivatives with phosphonate groups at C-17 were synthesized and characterized. These steroids are of pharmacological interest as potential 5 alpha-reductase inhibitors. Under the same conditions, methylation of lactam NH was observed using dimethyl phosphite.

Palladium-catalyzed homogeneous coupling reactions of steroids with organostannanes.

Direct and carbonylative coupling reactions of various steroid derivatives possessing iodo- and bromo-alkenyl moiety (17-iodo-androst-16-ene, 1, 17-bromoandrost-2,16-diene, 2, 17-iodo-4-aza-4-methylandrost-16-en-3-one, 3, 17-iodo-4-azaandrost-16-en-3-one, 4) with vinyltributylstannane and ethynyltributylstannane were carried out in the presence of various palladium catalysts. While carbonylation took place only with vinyltributylstannane, 17-vinyl-, and 17-ethynyl-delta 16 steroids were produced via direct coupling with vinyltributylstannane and ethynyltributylstannane, respectively. Activities of some catalysts based on Pd(0) and Pd(II) precursors were compared, and Pd(PPh3)4 was found to be superior to other complexes in most cases. In the coupling of 17-iodoandrost-16-ene with organostannanes Pd2(dba)3 + 8 AsPh3 in situ catalyst was found to be even more effective.

[Mass spectrometry of pipecuronium bromide and some related compounds]. / Tömegspektrometriás vizsgálatok a pipecuronium bromid és rokon vegyületei körében.

The mass spectral behaviour of the bis-quaternary salt pipecuronium bromide and some related Cn+ A-n type ammonium salts (n = 1, 2, 3) has been studied and compared. Under EI-MS conditions the evaporation of the samples preceded by in situ dealkylation led to formation of alkyl bromide and amine bases. It has been demonstrated that this technique, completed with quantitation of the relative amount of the decomposition products is applicable to get structure information about the basis part as well as the number and positions of the quaternary centres and the substituents at these centres. The FAB mass spectra of these mono-, bis- and this quaternary ammonium salts were found to be very interesting and provide direct structural information about the salt. They exhibit primary Cn+ intact cations and (Cn+ A-n + 1)+ single charged cluster ions and also fragments characteristic of partial structures at the quaternary centres.

[Synthesis of a new neuromuscular blocking agent, pipecuronium bromide (Arduan)]. / Egy új neuromuszkuláris blokkoló, a pipecuronium bromid (ARDUAN) szintézise.

A series of bisquaternary ammonio steroids having androstane skeleton have been prepared some of which possessed high neuromuscular blocking activity. One of the series 3 alpha, 17 beta-diacetoxy-2 beta, 16 beta-bis (4,4-dimethyl-1-piperazinyl)-5 alpha-androstane dibromide (19, pipecuronium bromide, ARDUAN) has proved to be a clinically useful agent of long duration of action without side effects. The preparation of pipecuronium bromide and its metabolites and the impurities are also described. The structure of 19 and related compounds was elucidated by spectrometric methods IR, NMR and MS.

[Excerpts from the investigations of pipecuronium bromide with NMR spectroscopy]. / Szemelvények a pipecuronium bromiddal kapcsolatos NMR spektroszkópiai vizsgálatokból.

The synthesis of Pipecuronium bromide together with the investigation of its impurity profile required the solution of a number of analytical and structural problems. NMR spectroscopical methods received a major role in the structure elucidation of the synthesized compounds. The quantitative assessment of contaminations was also realized by 1H NMR spectroscopy. Out of the large amount of undertaken investigations, here we provide the structural characterization of the contaminating regiosimers of an important intermediate (5 alpha-androst-2-en-17-on) formed in the course of the synthesis, together with the NMR signal assignments of the end-product (Pipecuronium bromide) as measured in D2O and a mixture of CDCl3/DMSO-d6. The structure of a minor contamination of the end-product is also given.

[Analysis of steroids. Part 40. Isolation and identification of unusual impurities in ethynodiol diacetate]. / Adatok a szteránvázas vegyületek analitikájához 40. Etinodiol-diacetát szokatlan szennyezéseinek izolálása és szerkezetük felderítése.

In the course of the estimation of the impurity profile of ethynodiol diacetate, in addition to common impurities such as norethisterone acetate, ethynodiol-3-acetate and alpha-ethynodiol diacetate, two unknown impurities were detected by analytical reversed phase HPLC (C-18 silica and 80% aq. methanol as the eluent) and isolated by normal phase preparative HPLC (silica and 98:2 mixture of hexane and 2-propanol as the eluent). The 1H- and 13C-NMR spectra of the isolated impurities revealed that their structures could be characterized as the E and Z isomers of an analogue of EDDA containing "trimerised acetyl" group at the 17-hydroxy group (structures 4 and 4a). These structures were in good agreement with the extended UV spectra of the impurities and the mass spectra with the m/z 438 peak which can be derived from 4 and 4a by the loss of ketene.

Rearrangement of Photosynthetic Pigment Composition in C(4), C(3) and CAM Species During Drought and Recovery.

The response of C(4), C(3) and CAM species to naturally induced drought and their subsequent recovery are similar. However, there are differences in the degree of the pigment responses, which are related to the differences in the pigment composition of the species. During drought the decrease of the lutein, neoxanthin and chl b content indicates the reduction of the LHC-xanthophyll-proteins, while the considerably increased level of ß-carotene, together with the elevated chl a/b ratio, reflect the increased amounts of chl a/ß-carotene-pigment-proteins. Moreover, from the pigment data it is concluded that the species seem to possess during drought a higher proportion of pigment-proteins of PSI than pigment-proteins of PS II. These reactions to drought decrease gradually in the direction of C(4)-C(3)-CAM (succulence). The C(4)Festuca vaginata responds with a considerable change in its pigment composition, while this is moderate in CAM Sedum, and C(3)Achillea occupies an intermediate position.

Changes of chloroplast ultrastructure and carbohydrate level in festuca, achillea and sedum during drought and after recovery.

The changes of chloroplast ultrastructure and carbohydrate level in C(4) sclerophyllous Festuca vaginata, C(3) malacophyllous Achillea ochroleuca and CAM succulent Sedum sexangulare were investigated during naturally induced drought and after subsequent recovery. Chloroplasts of the species show some characteristic changes due to drought: decreased volume, permanent adhesions within the grana, partitions become thinner, lipid droplets increase in number and size. Contraction of the stroma, swelling and blistering of thylakoids are characteristic of Sedum chloroplast and mesophyll chloroplasts of Festuca. Structure of bundle sheath chloroplasts of C(4) Festuca scarcely shows changes during drought and after recovery. During drought and subsequent recovery in the chloroplasts onf Achillea the slightest changes of the stromal and grana lamellae region can be observed. During drought starch grains are characteristic of chloroplasts of Achillea and Sedum; they disappear after recovery. Achillea and Sedum leaves contain more starch during drought than after recovery, while the starch content in Festuca is unchanged. There is more soluble sugar in Festuca and Sedum during drought than after recovery, although the amount of soluble sugar in Achillea is decreased during drought.

Synthesis of 2 beta,16 beta-bis-(4'-dimethyl-1'-piperazino)-3 alpha,17 beta-diacetoxy-5 alpha-androstane dibromide and related compounds.

A series of bisquaternary ammonio steroids having androstane skeletons have been prepared some of which possessed high neuromuscular blocking activity. One of the series 2 beta,16 beta-bis-(4'-dimethyl-1'-piperazino)-3 alpha, 17 beta-diacetoxy-5 alpha-androstane-dibromide (9, pipercurium bromide, Arduan) has proved to be a clinically useful agent of medium duration of action without side effects. The preparation of these ammonio steroids and structure-activity relationships within the series are described. The structure of 9 and related compounds was elucidated by spectrometric methods IR, NMR and MS.

The effect of the steroid muscle relaxant pipecurium bromide on the acetylcholinesterase activity of red blood cells in vitro.

The acetylcholinesterase (AchE) inhibitory effect of a muscle relaxant 2 beta,16 beta-bis-(4'-dimethyl-1'-piperazino)-3 alpha,17 beta-diacetoxy-5 alpha-androstane dibromide (pipecurium bromide, RGH-1106, Arduan), was studied in vitro. The inhibition of AchE activity of human red blood cells, expressed as pI50, was 3.99, whereas that of serum cholinesterase (ChE) was 4.33. The AchE inhibitor action was reversible. The inhibition was not influenced by the combined administration of promethazine or atropine. The combined effect of pipecurium bromide and of some other diamino-azasteroid agent proved to be additive. Pipecurium bromide showed mixed-type inhibitory effect both on AchE and ChE.