Posterior Reversible Encephalopathy Syndrome in late postpartum eclampsia.

Posterior Reversible Encephalopathy Syndrome (PRES) is a neurological complication associated with several medical conditions and it has been described in clinical findings of seizures, headache, vomiting, altered mental status, and visual changes and focal neurologic deficit, in conjunction with radiological findings of primarily posterior cerebral white matter edema of both cerebral hemispheres. PRES can develop in a wide array situations including pregnancy and postpartum in patients with or without symptoms and signs of eclampsia. A prompt diagnosis of PRES by magnetic resonance imaging and an immediate antihypertensive and anticonvulsant therapy can help to prevent serious complications. The clinical case presented deals with a 35 year-old pregnant woman whose history of eclampsia was observed after a cesarean section.

Laccase isoforms with unusual properties from the basidiomycete Steccherinum ochraceum strain 1833.

AIMS: To isolate and characterize the laccase isoforms from S. ochraceum 1833 - a new active producer of high extracellular laccase activity. METHODS AND RESULTS: Three laccase isoforms (laccases I, II and III) with 57.5, 59.5 and 63 kDa molecular masses respectively were purified from S. ochraceum 1833 and in contrast to the known laccases had strongly pronounced absorption at 611 nm with molar extinction coefficients ranging from 7170 to 7830 mol(-1) l cm(-1). All isoforms showed maximal activity with ABTS at low pH (

Protease inhibitors, part 13: Specific, weakly basic thrombin inhibitors incorporating sulfonyl dicyandiamide moieties in their structure.

A series of compounds has been prepared by reaction of dicyandiamide with alkyl/arylsulfonyl halides as well as arylsulfonylisocyanates to locate a lead for obtaining weakly basic thrombin inhibitors with sulfonyldicyandiamide moieties as the S1 anchoring group. The detected lead was sulfanilyl-dicyandiamide (K1 of 3 microM against thrombin, and 15 microM against trypsin), which has been further derivatized at the 4-amino group by incorporating arylsulfonylureido as well as amino acyl/dipeptidyl groups protected at the amino terminal moiety with benzyloxycarbonyl or tosylureido moieties. The best compound obtained (ts-D-Phe-Pro-sulfanilyl-dicyandiamide) showed inhibition constants of 9 nM against thrombin and 1400 nM against trypsin. pKa measurements showed that the new derivatives reported here do indeed possess a reduced basicity, with the pKa of the modified guanidine moieties in the range 7.9-8.3 pKa units. Molecular mechanics calculations showed that the preferred tautomeric form of these compounds is of the type ArSO2N=C(NH2) NH-CN, probably allowing for the formation of favorable interaction between this new anchoring group and the active site amino acid residue Asp 189, critical for substrate/inhibitor binding to this type of serine protease. Thus, the main finding of the present paper is that the sulfonyldicyandiamide group may constitute an interesting alternative for obtaining weakly basic, potent thrombin inhibitors, which bind with less affinity to trypsin.

Arylsulfonyl-N,N-dialkyl-dithiocarbamates as tumor cell growth inhibitors: novel agents targeting beta-tubulin?

Reaction of sodium N,N-dimethyldithiocarbamate or N,N-diethyldithiocarbamate with arylsulfonyl halides afforded a series of arylsulfonyl-N,N-dialkyl-dithiocarbamates. The reactivity of these new derivatives with cysteine and glutathione has been investigated in order to identify derivatives that might label a cysteine residue of the heterodimeric protein tubulin which plays a critical physiological function in cell division and also possesses enzymatic activity as a GTP-ase. Since many antitumor drugs exert their action by binding to tubulin, inhibiting in this way microtubule association and provoking cell death, some of the most reactive compounds against the thiol reagents found in this work have been assayed for their antitumor activity. Indeed strong tumor cell growth inhibitory properties against several leukemia, non-small cell lung, ovarian, melanoma, colon, CNS, renal, prostate and breast cancer has been found in vitro for some of the 4-halogeno-, 4-methyl- or 4-carboxyphenyl-substituted arylsulfonyl-N,N-dialkyl-dithiocarbamates. Furthermore, some of these derivative were shown to act as in vitro tubulin polymerization inhibitors using a turbidimetric assay.

Prognostic significance of endothelial dysfunction in hypertensive patients.

BACKGROUND: Forearm endothelial dysfunction, characterized by an impaired vasodilating response to acetylcholine (ACh), may be associated with several cardiovascular risk factors, including essential hypertension. Although the prognostic value of coronary endothelial dysfunction has been demonstrated, that of forearm endothelial dysfunction is still unknown. Methods and Results-- Endothelium-dependent and -independent vasodilation was investigated in 225 never-treated hypertensive patients (age, 35 to 54 years) by intra-arterial infusion of increasing doses of ACh and sodium nitroprusside. Patients were divided into tertiles on the basis of their increase in ACh-stimulated forearm blood flow (FBF) from basal: group 1, from 30% to 184%; group 2, from 185% to 333%; and group 3, from 339% to 760% increase from basal. During a mean follow-up of 31.5 of months (range, 4 to 84 months), there were 29 major adverse events at the cardiac (n=19), cerebrovascular (n=9), or peripheral vascular (n=1) level. Events included myocardial infarction, angina, coronary revascularization procedures, stroke, transient cerebral ischemic attack, and aortoiliac occlusive disease. Event rate per 100 patient-years was 8.17, 4.34, and 2.02 in the first, second, and third tertiles of peak percent increase in FBF during ACh infusion. The excess risk associated with an FBF increase in the first tertile was significant (relative risk, 2.084; 95% CI, 1.25 to 3.48; P=0.0049) after controlling for individual risk markers, including 24-hour ambulatory blood pressure. CONCLUSIONS: Our data suggest that forearm endothelial dysfunction is a marker of future cardiovascular events in patients with essential hypertension.

Gel sequestration of heavy metals by Klebsiella oxytoca isolated from iron mat.

The enterobacterium Klebsiella oxytoca strain BAS-10 was isolated from sediments under an iron mat formed in a stream receiving leached waters from pyrite mine tailings. Under anaerobic laboratory conditions, BAS-10 fermented Fe(III)-citrate and Na-citrate giving CH(3)COOH and CO(2). In the presence of ferric citrate, BAS-10 secreted quantities of a thick gel containing glucose and/or mannose, if not other sugars. Sugar residues were observed in microbial aggregates using the sugar-specific concanavalin A lectin conjugated with fluorescein and imaged by a scanning confocal laser microscope. The gel bound Fe(III) which quickly precipitated. During fermentation, however, half the initial Fe(III) concentration was reduced to Fe(II) which did not bind to the gel and remained in solution. BAS-10 showed a high tolerance to heavy metals. Its growth was not inhibited by 1 mM Zn-, Pb- or Cd-acetate. These cations also co-precipitated with the iron gel, suggesting a possible application of this strain for abatement of toxic metals under anaerobic conditions.

Antimycobacterial activity of 9-sulfonylated/sulfenylated-6-mercaptopurine derivatives.

A series of 9-sulfonylated/sulfenylated-6-mercaptopurines has been prepared by reaction of 6-mercaptopurine with sulfonyl/sulfenyl halides. These compounds constitute a new class of potent antimycobacterial agents, possessing MIC values against Mycobacterium tuberculosis H37Rv in the range of 0.39-3.39 microg/mL, as well as appreciable activity against Mycobacterium avium. Furthermore, a compound of this small series exhibited good activity (MIC under 1 microg/mL) against several drug resistant strains of M. tuberculosis.

Carbonic anhydrase inhibitors: 4-sulfamoyl-benzenecarboxamides and 4-chloro-3-sulfamoyl-benzenecarboxamides with strong topical antiglaucoma properties.

Reaction of 4-carboxy-benzenesulfonamide or 4-chloro-3-sulfamoyl benzoic acid with carboxy-protected amino acids/dipeptides, or aromatic/heterocyclic sulfonamides/mercaptans afforded the corresponding benzene-carboxamide derivatives. These were tested as inhibitors of three carbonic anhydrase (CA) isozymes, CA I, II and IV. Some of the new derivatives showed affinity in the low nanomolar range for isozymes CA II and IV, involved in aqueous humor secretion within the eye, and were tested as topically acting anti-glaucoma agents, in normotensive and glaucomatous rabbits. Good in vivo activity and prolonged duration of action has been observed for some of these derivatives, as compared to the clinically used drugs dorzolamide and brinzolamide. Some of the 4-chloro-3-sulfamoyl benzenecarboxamides reported here showed higher affinity for CA I than for the sulfonamide avid isozyme CA II.

Efficient polycyclic aromatic hydrocarbons dihydroxylation in direct micellar systems.

Optimization of whole-cell bioconversion of the polycyclic aromatic hydrocarbons (PAHs) anthracene, phenanthrene, and naphthalene to the enantiomerically pure corresponding cis-dihydroxydihydro derivatives by the Escherichia coli JM109 (pPS1778) recombinant strain, carrying the naphthalene dioxygenase and corresponding regulatory genes cloned from Pseudomonas fluorescens N3, in micellar systems, is presented. We show that direct microemulsion systems, where a nonionic surfactant such as 1.5% (v/v) Triton X-100 plus 0.6% to 1.0% (v/v) selected oils are able to solubilize the PAHs tested at relatively high concentrations (initial concentrations in the reaction medium > or =10 mM for naphthalene and phenanthrene and > or =2 mM for anthracene), and allow for more efficient substrate bioconversion. These media, while not affecting bacteria viability and performance, provide increased efficiency and final product yields (100% for naphthalene, >30% for anthracene, >60% for phenanthrene). The phase behavior of the direct microemulsion systems for the different substrates and oils utilized was monitored as a function of their volume fraction by light scattering experiments, and related to the bioconversion results. For anthracene and phenanthrene, the dihydroxylated products have an inhibitory effect on the conversion reactions, thus hindering complete turnover of the substrates. We ascertain that such inhibition is reversible because removal of the products formed allowed the process to start over at rates comparable to initial rates. To allow for complete conversion of the PAHs tested a stepwise or continuous separation of the product formed from the micellar reaction environment is being developed.

Protease inhibitors: synthesis of a series of bacterial collagenase inhibitors of the sulfonyl amino acyl hydroxamate type.

A series of sulfonyl amino acyl hydroxamates incorporating alkyl/arylsulfonyl-N-2-nitrobenzyl-L-alanine was prepared. Related compounds were obtained by reaction of N-2-nitrobenzyl-L-Ala with aryl isocyanates, arylsulfonyl isocyanates, or benzoyl isothiocyanate, followed by the conversion of the COOH into the CONHOH moiety. The new compounds were assayed as inhibitors of the Clostridium histolyticum collagenase (ChC), a bacterial protease involved in the degradation of extracellular matrix. Many of the obtained hydroxamates proved to be effective bacterial collagenase inhibitors, the main contributor to activity being the substitution pattern at the sulfonamido moiety. The best ChC inhibitors were those containing pentafluorophenylsulfonyl and 3- and 4-protected-aminophenylsulfonyl P(1)(') groups among others, with affinities in the low nanomolar range. This study also proves that the 2-nitrobenzyl- moiety, similarly to the 4-nitrobenyl one previously investigated (Scozzafava, A.; Supuran, C. T. J. Med. Chem. 2000, 43, 1858-1865) is an efficient P(2)(') anchoring moiety for obtaining potent bacterial collagenase inhibitors.

Carbonic anhydrase inhibitors, interaction of boron derivatives with isozymes I and II: a new binding site for hydrophobic inhibitors at the entrance of the active site as shown by docking studies.

The interaction of human carbonic anhydrase (hCA) isozymes I and II with boron derivatives was investigated by kinetic and spectroscopic studies. These derivatives, tested as new inhibitors of carbonic anhydrase, are sulfonamide and non-sulfonamide boron derivatives and some of them proved to be moderately efficient inhibitors of hCA I and hCA II, their activities being comparable to those of the unsubstituted sulfonamides, the classical inhibitors of these zinc enzymes. Ph(2) BOH, one of the compounds with the highest affinity for hCA II in the present study, has been docked within the active site. After minimisation it was found situated at 7.9 A from zinc, within the hydrophobic half of the active site, in Van der Waals contacts with the amino acid residues: Val 121, Phe 130, Val 135, Leu 141, Val 143, Val 207 and Pro 201. This is the first time that a CA inhibitor has been found to bind at the edge of the active site cavity, similarly to the CA activator histamine, which binds on the hydrophilic half. This finding may be of importance also for the design of novel types of inhibitors with increased affinity for the different CA isozymes.

Carbonic anhydrase inhibitors: synthesis and inhibition against isozymes I, II and IV of topically acting antiglaucoma sulfonamides incorporating cis-5-norbornene-endo-3-carboxy-2-carboxamido moieties.

Sulfonamides incorporating cis-5-norbornene-endo-3-carboxy-2-carboxamido moieties in their molecules were prepared by reaction of cis-5-norbornene-endo-2,3-dicarboxylic anhydride with aromatic/heterocyclic sulfonamides possessing free amino, hydrazino, or imino groups. Some of these compounds showed very good CA II and CA IV inhibitory properties, with affinities for the enzymes in the low nanomolar range. Some of the most active CA II inhibitors reported here have been formulated as aqueous solutions for topical administration as antiglaucoma agents in normotensive rabbits. Some of the derivatives incorporating cis-5-norbornene-endo-3-carboxy-2-carboxamido and aromatic sulfonamide moieties (as sodium salts) showed effective and longer lasting intraocular pressure (IOP) lowering as compared to dorzolamide, a widely used topical antiglaucoma drug. Compounds incorporating cis-5-norbornene-endo-2,3-carboximido moieties, although stronger in vitro CA inhibitors as compared to the corresponding cis-5-norbornene-endo-3-carboxy-2-carboxamido-;derivatives, showed no topical IOP lowering properties, probably due to their very poor water solubility.

Carbonic anhydrase inhibitors: sulfonamides as antitumor agents?

Novel sulfonamide inhibitors of the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1) were prepared by reaction of aromatic or heterocyclic sulfonamides containing amino, imino, or hydrazino moieties with N,N-dialkyldithiocarbamates in the presence of oxidizing agents (sodium hypochlorite or iodine). The N,N-dialkylthiocarbamylsulfenamido-sulfonamides synthesized in this way behaved as strong inhibitors of human CA I and CA II (hCA I and hCA II) and bovine CA IV (bCA IV). For the most active compounds, inhibition constants ranged from 10(-8) to 10(-9) M (for isozymes II and IV). Three of the derivatives belonging to this new class of CA inhibitors were also tested as inhibitors of tumor cell growth in vitro. These sulfonamides showed potent inhibition of growth against several leukemia, non-small cell lung, ovarian, melanoma, colon, CNS, renal, prostate and breast cancer cell lines. With several cell lines. GI50 values of 10-75 nM were observed. The mechanism of antitumor action with the new sulfonamides reported here remains obscure, but may involve inhibition of CA isozymes which predominate in tumor cell membranes (CA IX and CA XII), perhaps causing acidification of the intercellular milieu, or inhibition of intracellular isozymes which provide bicarbonate for the synthesis of nucleotides and other essential cell components (CA II and CA V). Optimization of these derivatives from the SAR point of view, might lead to the development of effective novel types of anticancer agents.

Carbonic anhydrase inhibitors: synthesis of sulfonamides incorporating dtpa tails and of their zinc complexes with powerful topical antiglaucoma properties.

Reaction of diethylenetriamino pentaacetic acid (dtpa) dianhydride with aromatic/heterocyclic sulfonamides possessing a free amino/imino/hydrazino/hydroxy group afforded bis-sulfonamides containing metal-complexing, polyamino-polycarboxylic acid moieties in their molecule. The corresponding mono-sulfonamide derivatives of dtpa were also obtained by an alternative method, from the free acid. Zn(II) complexes of these new sulfonamides were then prepared. Many of these derivatives showed nanomolar affinity towards isozymes I, II and IV of carbonic anhydrase (CA). Some of the best inhibitors were applied as 2% water solutions/suspensions into the eye of normotensive or glaucomatous albino rabbits, when strong and long-lasting intraocular pressure (IOP) lowering was observed.

Carbonic anhydrase activity modulators: synthesis of inhibitors and activators incorporating 2-substituted-thiazol-4-yl-methyl scaffolds.

A small series of 2-[4-(4-substituted-phenylsulfonyl)phenyl]-4-chloromethylthiazoles has been used as a scaffold for the preparation of carbonic anhydrase (CA) inhibitors and activators. For obtaining CA inhibitors, zinc-binding functions of the sulfamide and sulfamate type have been introduced into the molecules of these compounds, by reaction of the chloromethyl derivatives with sodium sulfamide/sodium sulfamate. For obtaining CA activators, the primary amino function has been introduced in these molecules by means of the Gabriel syntheses. The new sulfamide/sulfamates were effective CA II and CA IV inhibitors, but showed no inhibitory activity against isozyme I. The new amines on the other hand were much more effective CA I, II and IV activators compared to histamine, the lead compound used for their synthesis.

Antimycobacterial activity of 3,4-dichlorophenyl-ureas, N,N-diphenyl-ureas and related derivatives.

Substituted urea derivatives were prepared by reacting 3,4-dichlorophenyl isocyanate with amino acids, dipeptides, histamine or dicyandiamide among others, or from N,N-diphenyl-carbamoyl chloride and amino acids, dipeptides, or histamine. Other derivatives were obtained by reaction of PABA or PAS with arylsulfonyl halides. Some of the new compounds showed appreciable activity as antimycobacterial agents against Mycobacterium tuberculosis H37Rv, producing an inhibition of growth in the range of 80-89%, at a concentration of 6.25 microM. Some derivatives of this series might constitute interesting lead molecules for designing novel types of drugs effective against M. tuberculosis, a re-emerging pathogen both in the developed and under-developed countries.

Carbonic anhydrase inhibitors: allylsulfonamide, styrene sulfonamide, N-allyl sulfonamides and some of their Si, Ge, and B derivatives.

Unsubstituted aromatic, heterocyclic and perfluoroalkylic sulfonamides possessing the general formula RSO2NH2 act as powerful inhibitors of the zinc enzyme carbonic anhydrase (CA). Unsaturated primary/substituted sulfonamides have never been investigated for their interaction with the enzyme. Here it is shown that such compounds, and more precisely allyl-sulfonamide and trans-styrene sulfonamide possessing the above general formula (with R=CH2=CH-CH2- and C6H5-CH=CH-, respectively) behave as nanomolar inhibitors of the physiologically relevant isozymes CAI and CAII. Some other derivatives of these two leads (incorporating Si(IV), Ge(IV) and B(III) moieties among others) were also synthesized and investigated for their interaction with CA, but showed decreased affinity for both isozymes. The structure-activity relationship for this class of CA inhibitors is discussed. Furthermore, it was observed that allylsulfonyl chloride is a strong CA inactivator, probably by reacting with amino acid residues critical for the catalytic cycle.

Carbonic anhydrase inhibitors: metal complexes of a sulfanilamide derived Schiff base and their interaction with isozymes I, II and IV.

Metal complexes of aromatic/heterocyclic sulfonamides act as stronger inhibitors of the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1) as compared to the uncomplexed sulfonamides from which they are derived. Here we report the synthesis and inhibition studies against the physiologically relevant isozymes CA I, CA II and CA IV, of a series of metal complexes (Co(II), Ni(II) and Cu(II) derivatives) of a Schiff-base ligand, obtained from sulfanilamide and salicylaldehyde. The best activity was observed for the Cu(II) and Co(II) complexes, against CA II and CA IV, for which inhibition constants in the range of 15-39 and 72-108nM, respectively, were seen. The enhanced efficacy in inhibiting the enzyme may be due to a dual mechanism of action of the metal complexes, which interact with CA both by means of the sulfonamide moieties as well as the metal ions present in their molecule.

Carbonic anhydrase inhibitors: topically acting antiglaucoma sulfonamides incorporating phthaloyl and phthalimido moieties.

Sulfonamides incorporating 2-carboxy-benzenecarboxamido (phthaloyl) moieties in their molecules were prepared by reaction of phthalic anhydride with aromatic/heterocyclic sulfonamides in mild conditions. Another closely related series of derivatives was prepared by reaction of the same reagents in more energetic conditions, when the corresponding phthalimides were obtained. Some of these compounds showed very good in vitro carbonic anhydrase (CA) isozymes I, II and IV inhibitory properties, with affinities for the enzymes in the low nanomolar range for the best inhibitors. Some of the potent CA inhibitors reported here have been formulated as sodium salts, in aqueous solutions for topical administration as antiglaucoma agents, in normotensive/glaucomatous rabbits. Only the derivatives possessing good water solubility, showed effective and longer lasting topical intraocular pressure (IOP) lowering than dorzolamide and brinzolamide, two clinically used topical antiglaucoma drugs. All the in vivo effective new compounds belonged to the first series of derivatives, whereas the corresponding phthalimides, although stronger in vitro CA inhibitors were devoid of topical IOP lowering properties, probably due to their unproper physico-chemical properties.

Carbonic anhydrase inhibitors: water-soluble 4-sulfamoylphenylthioureas as topical intraocular pressure-lowering agents with long-lasting effects.

A series of sulfonamides has been obtained by reaction of 4-isothiocyanatobenzenesulfonamide with amines, amino acids, and oligopeptides. The new thiourea derivatives showed strong affinities toward isozymes I, II, and IV of carbonic anhydrase (CA, EC 4.2.1.1). In vitro inhibitory power was good (in the low-nanomolar range) for the derivatives of beta-phenylserine and alpha-phenylglycine, for those incorporating hydroxy and mercapto amino acids (Ser, Thr, Cys, Met), hydrophobic amino acids (Val, Leu, Ile), aromatic amino acids (Phe, His, Trp, Tyr, DOPA), and dicarboxylic amino acids as well as di/tri/tetrapeptides among others. Such CA inhibitors displayed very good water solubility (in the range of 2-3%) mainly as sodium (carboxylate) salts, with pH values of the obtained solutions being 6.5-7.0. Some of these preparations (such as the derivatives of Ser, beta-Ph-Ser, Leu, Asn, etc.) strongly lowered intraocular pressure (IOP) when applied topically, directly into the normotensive/glaucomatous rabbit eye, as 2% water solutions. It is interesting to note that not all the powerful CA inhibitors designed in the present study showed topical IOP-lowering effects (such as, for instance, the Cys and Lys derivatives, devoid of such properties) whereas the Pro, Arg, and oligopeptidyl thiourea derivatives showed reduced efficacy when administered topically. This may be due to the very hydrophilic nature of some of these compounds, whereas inhibitors with balanced hydro- and liposolubility also showed optimal in vivo effects. The interesting pharmacological properties of this new type of CA inhibitors, correlated with the neutral pH of their solutions used in ophthalmologic applications, make them attractive candidates for developing novel antiglaucoma drugs devoid of major ocular side effects.