Acute sarcoidosis: 3 cases in an acute medical clinic.

Sarcoidosis is a cryptogenic multisystem granulomatous disorder. We present three patients who presented acutely with erythema nodosum in our Medical Assessment Unit (MAU) or attended our clinic, subsequently diagnosed with acute sarcoidosis. In doing so, we aim to demonstrate that this presentation can easily be seen on the acute medical take, focussing on the management of acute sarcoidosis in association with erythema nodosum. Although patients will often not display florid systemic upset on presentation, we recommend follow-up after initial presentation, to ensure good resolution of symptoms.

Furanoid sugar amino acids as dipeptide mimics in design of analogs of vasoactive intestinal peptide receptor binding inhibitor.

In this study we describe the development of peptidomimetic analogs of the potent vasoactive intestinal peptide receptor binding inhibitor, Leu(1) -Met(2) -Tyr(3) -Pro(4) -Thr(5) -Tyr(6) -Leu(7) -Lys(8) -OH 1, by incorporating furanoid sugar amino acids (SAAs) 2-4 into the molecule. The furanoid SAAs 2-4 were used as dipeptide isosteres to replace Tyr(3) -Pro(4) or Pro(4) -Thr(5) in sequence 1. The resulting analogs 5-9 were tested for their anti-cancer activities in vitro, following the standard MTT assay on a panel of human cancer cell lines. One of the potent analogs, 6a was tested in vivo for tumor regression on primary colon tumor xenografted nude mice. Our experimental results suggest that many of these analogs show either retention or enhancement of biological activity.

Conformational studies of peptides containing cis-3-hydroxy-D-proline.

Conformational analysis of peptides containing cis-3-hydroxy-d-proline (d-cis-3-Hyp) by NMR studies revealed that the 3-hydroxyl group in this amino acid plays a significant role in the overall three-dimensional structures of the peptides. When the d-cis-3-Hyp had its 3-hydroxyl group protected as the benzyl (Bn) ether, the peptide displayed a beta-hairpin structure in both CDCl(3) and DMSO-d(6). Even after the removal of the Bn group, the resulting deprotected compound retained the same structure as in the protected version in CDCl(3). However, in polar solvent DMSO-d(6), the C-terminal strand of the hydroxyl-deprotected peptide flipped to the side of the hydroxyl group, breaking the hairpin to form a pseudo beta-turn-like nine-membered ring structure involving an intramolecular hydrogen bond between LeuNH --> HypC3-OH.

Cyclic homooligomers of furanoid sugar amino acids.

Cyclic homooligomers of mannose-derived furanoid sugar amino acid 1 [H-Maa(Bn(2))-OH] were synthesized by using BOP reagent in the presence of DIPEA under dilute conditions that converted the sugar amino acid monomer directly into its cyclic homooligomers 3a and 4a. The glucose-based sugar amino acid 2 [H-Gaa(Bn(2))-OH] under the same reaction conditions gave a bicyclic lactam 5a as the major product. Cyclic homooligomers of 2 were prepared by cyclizing their linear precursors 6 and 7 leading to the formation of cyclic peptides 8a and 9a, respectively. Conformational analysis by NMR and constrained MD studies revealed that all the cyclic products, 3, 4, 8, and 9, had symmetrical structures. The deprotected cyclic trimer of Maa 3b displayed a conformation in which all the C=O and the N-H bonds of the molecule point in opposite directions. In the deprotected cyclic tetramer of Maa 4b, the COs and NHs were in the plane of the ring with the former pointing to outside and the latter inside the ring. The structure of the cyclic Gaa dimer 8b displayed an unusual six-membered intramolecular hydrogen bond between NH(i)() --> C3-O(i)()(-)(1) and a syn orientation between the C2-H and CO. In this molecule, the C2-hydrogens and the COs can be seen on one side of the ring while the NHs point to the other side. Addition of the bicyclic lactam 5b resulted in the influx of Na(+) ions across the lipid bilayer leading to the dissipation of valinomycin-mediated K(+) diffusion potential.

Studies on novel peptidomimetics having bi-directional dispositions of hydroxylated D-Pro-Gly motifs anchored on a C(2)-symmetric iminosugar-based foundation.

A rigid pyrrolidine based scaffold comprising of 2,5-dideoxy-2,5-imino-D-idaric acid (1) is developed. Attachment of peptide strands to the carboxylic groups at both ends of this novel template led to the peptidomimetics 2 and 3. Conformational analysis by NMR studies revealed that compounds 2b, 3b and 2c, 3c take interesting turn structures (C(2) symmetric for 2c and 3c) in DMSO-d(6) consisting of identical intramolecular hydrogen bonds at two ends between LeuNH --> sugar-OH as depicted in structure A, whereas 2a and 3a display structures with regular beta-turns with hydrogen bonds between LeuNH --> Boc-C=O in one-half of their molecular frameworks (structure B), characteristic of the turn structures commonly observed in "D-Pro-Gly"-containing peptides. These results suggest that a cis hydroxyl group at the 3-position of the proline residue favors a pseudo beta-turn-like nine-membered ring structure in hydroxyproline-containing peptides involving an intramolecular hydrogen bond between the hydroxyl and the i + 2 backbone amide.

Purification and characterization of a growth-regulating laccase from Pleurotus florida.

Pleurotus florida produces two laccase enzymes (L1 and L2) within which L2 is associated with the vegetative growth of the fungus. In the present investigation the L2 has been purified to homogeneity and characterized. The molecular mass of the enzyme has been determined to be 73 kDa and 70 kDa by gel filtration chromatography and SDS-PAGE, respectively. The purified enzyme shows a pI value of 4.2. The optimum reaction temperature is 50 degrees C. Spectroscopic analysis reveals that L2 has two copper atoms, a type I copper and a type II copper. The Km and some other kinetic parameters of L2 has been determined.

Chemistry of potent anti-cancer compounds, amphidinolides.

Amphidinolides A-V represent a family of cytotoxic marine natural products with diverse structural features and pronounced biological activities. Kobayashi and his research group have been reporting over the years the discoveries of these remarkable molecules, one after another, since 1986 when the first report of the series appeared. Thanks to their perseverance and painstaking research, the family is still expanding. The unique structural features and biological activity profiles of these macrolides have obviously attracted the attention of organic chemists worldwide. The total syntheses of three members of the family, amphidinolides J, K and P, have already been achieved. This review tries to chronicle the fascinating chemistries of amphidinolides, studies on the syntheses of some of these molecules and their biological activity profiles.

Synthesis and conformational studies of peptidomimetics containing furanoid sugar amino acids and a sugar diacid.

Furanoid sugar amino acids (1) were synthesized and used as dipeptide isosteres to induce interesting turn structures in small linear peptides. They belong to a new variety of designed hybrid structures that carry both amino and carboxyl groups on rigid furanose sugar rings. Four such molecules, 6-amino-2,5-anhydro-6-deoxy-D-gluconic acid (3, Gaa) and its mannonic (4, Maa), idonic (5, Iaa), and a 3,4-dideoxyidonic (6, ddIaa) congeners were synthesized. The synthesis followed a novel reaction path in which an intramolecular 5-exo S(N)2 opening of the hexose-derived terminal aziridine ring in 2 by the gamma-benzyloxy oxygen with concomitant debenzylation occurred during pyridinium dichromate oxidation of the primary delta-hydroxyl group to carboxyl function, leading to the formation of furanoid sugar amino acid frameworks in a single step. Incorporation of these furanoid sugar amino acids into Leu-enkephalin replacing its Gly-Gly portion gave analogues 8-11. Detailed structural analysis of these molecules by circular dichroism (CD) and various NMR techniques in combination with constrained molecular dynamics (MD) simulations revealed that two of these analogues, 8a and 10a, have folded conformations composed of an unusual nine-membered pseudo beta-turn-like structure with a strong intramolecular H-bond between LeuNH --> sugarC3-OH. This, in turn, brings the two aromatic rings of Tyr and Phe in close proximity, a prerequisite for biological activities of opioid peptides. The analgesic activities of 8a,b determined by mouse hot-plate and tail-clip methods were similar to that of Leu-enkephalin methyl ester. The syn disposition of the beta-hydroxycarboxyl motif on the sugar rings appears to be the driving force to nucleate the observed turn structures in some of these molecules (8 and 10). Repetition of the motif on both sides of a furanose ring resulted in a novel molecular design of sugar diacid, 2,5-anhydro-D-idaric acid (7, Idac). Bidirectional elongation of the diacid moieties of 7 with identical peptide strands led to the formation of a C2-symmetric reverse-turn mimetic 12 which displayed a very ordered structure consisting of identical intramolecular H-bonds at two ends between LeuNH --> sugar-OH, the same as in 8 and 10.

Accumulation of a natural substrate of laccase in gills of Pleurotus florida during sporulation.

During sporulation, laccase activity of Pleurotus florida decreased to a minimum level in spite of increase in the number of isozymes. An endogenous laccase substrate was detected especially in the gill structure of the sporophore, which competitively inhibited oxidation of guaiacol by the enzyme during in vitro assay. Appearance of the laccase substrate in the gill structure may be linked with the sporulation phenomenon.

2,5-Anhydro sugar diacid and 2,5-anhydro sugar diamine based C 2 symmetric peptidomimetics as potential HIV-1 protease inhibitors.

Conformationally constrained molecular frameworks of the 2,5-anhydro sugar diacid (9) and 2,5-anhydro sugar diamines (10, 11) were used to construct architecturally beautiful novel C 2 symmetric peptidomimetics 1-8. Although none of these compounds showed any significant HIV-1 protease inhibitory activity, further refinements in design may lead to protease inhibitors based on these rigid carbohydrate-derived scaffolds.

Purification and characterization of laccase-1 from Pleurotus florida.

Pleurotus florida (ITCC 3308) produces two laccase enzymes (L1 and L2) in potato-dextrose media containing 0.5% yeast extract. Concentrated culture filtrate was separated on DEAE-Sephadex (A-50) column into two enzyme peaks, subsequently named L1 and L2. The L1 enzyme has been purified to homogeneity by ion-exchange and gel-permeation chromatography. L1 is a monomeric glycoprotein with a molar mass of 77 and 82 kDa as determined by SDS-PAGE and gel-filtration chromatography, respectively. The pI value of L1 has been determined to be 4.1. The optimum reaction temperature of the enzyme is 50 degrees C. The Km and some other kinetic parameters of L1 have been determined. Cyanide and azide completely inhibit the enzyme activity. The enzyme was fully active in 1:1 (V/V) buffer-chloroform for at least 2 h. Spectroscopic analysis revealed that the enzyme has four copper atoms, a type 1 copper, a type 2 copper and a type 3 binuclear copper.

A comparative study of balloon mitral valvuloplasty and closed mitral commissurotomy in patients with rheumatic mitral stenosis.

Rheumatic mitral stenosis is frequently encountered in our country. It affects younger population and is a major cause of morbidity Mitral valvotomy is the definitive therapy for this disease and can be achieved by closed mitral commissurotomy (CMC), open mitral commissurotomy (OMC) or by percutaneous transluminal mitral valvuloplasty (PTMV). Compared to CMC, PTMV is less invasive but more expensive at this moment. With the reduction of cost, PTMV may become the procedure of choice for the treatment of rheumatic mitral stenosis in future.

Activation of parietal cell by mercaptomethylimidazole: a novel inducer of gastric acid secretion.

Mercaptomethylimidazole (2-Mercapto-1-methylimidazole, MMI), an antithyroid drug of thionamide group, significantly activated the parietal cell for acid secretion, as evidenced by increased O2 consumption by more than 2.5-fold over the basal level. When compared, MMI-induced activation was similar to that of histamine but significantly higher than that of isobutylmethylxanthine or carbachol. Activation by MMI was not prevented by receptor blockers of the parietal cell, indicating that its effect was not mediated through the cell surface histamine-H2 receptor or the muscarinic receptor. However, the activation was almost completely blocked only by omeprazole, an established inhibitor of the terminal proton-pumping H+-K+-ATPase of the parietal cell. That MMI-induced activation was coupled with the H+ transport was further confirmed by significant increase in [14C]-aminopyrine uptake by MMI in rabbit gastric gland preparation. MMI-dependent activation of the parietal cell correlated well with the inhibition of the endogenous peroxidase activity. In vitro studies indicated that MMI irreversibly inactivated both peroxidase and catalase activity of the parietal cell in presence of H2O2. As inactivation of these H2O2-scavenging enzymes should increase accumulation of intracellular H2O2, the effect of latter was studied on acid secretion. H2O2 at a low concentration, stimulated acid secretion by sevenfold in isolated gastric mucosa, which was sensitive to omeprazole. It also significantly stimulated [14C]-aminopyrine uptake in gastric gland preparation. We suggest that MMI activated parietal cells to stimulate acid secretion by endogenous accumulation of H2O2 through inactivation of the peroxidase-catalase system.

Design and synthesis of a rapamycin-based high affinity binding FKBP12 ligand.

BACKGROUND: The immunosuppressants rapamycin, ascomycin, FK506, and cyclosporin act by binding to a class of cytosolic proteins, the immunophilins. In the case of FK506, ascomycin and cyclosporin, the target of the immunophilin-immunosuppressant complex is calcineurin; in the case of rapamycin, the target is FRAP (TOR/RAFT1). Rapamycin, ascomycin and FK506 have a common domain responsible for binding to FKBP12, their cellular receptor, and different effector domains that determine the target of the complex. Both domains are necessary for signal transduction and biological activity. RESULTS: A hybrid molecule containing the rapamycin-FK506-ascomycin binding domain and a peptide tether has been designed, synthesized and biologically evaluated. The designed compound binds to FKBP12 with high affinity but has no biological activity, as expected from its lack of an effector domain. CONCLUSIONS: The designed rapamycin-based FKBP12 ligand exhibits powerful binding properties but, unlike rapamycin, shows no activity in IL-6 dependent B-cell proliferation and, in contrast to FK506, shows no activity in the IL-2 reporter assay. The modular nature of this designed molecule should make it possible to generate a series of compounds with effector domains for targeting either calcineurin or FRAP (TOR/RAFT1) or both, as potential biological tools and immunosuppressive agents.

Application of filter paper method for collection of blood for MLPA test.

The results of MLPA test using serum and filter paper eluate have been compared in this paper. Testing 64 patient samples at 1:32 dilution, 31 were negative by both serum and eluate, 20 were positive by both, six were positive only by serum and one was positive only eluate. In six other cases eluate gave equivocal results while serum result was clearly positive. Some eluates negative at 1:32 dilution gave weak positive agglutination at 1:16 dilution.

Abnormal cardiovascular reflexes in patients with gastro-oesophageal reflux.

Using five non-invasive tests, abnormalities of cardiovascular reflex function were found in 20 of 50 patients with gastro-oesophageal reflux. Abnormalities of pupil cycle time, an index of non-vagal parasympathetic function, were found in only a few patients, implying that the cardiovascular abnormalities observed were not part of a generalised parasympathetic defect. The findings are consistent with the hypothesis that an abnormality of vagal function may contribute to the pathogenesis of gastro-oesophageal reflux.

Effect of omeprazole on lower oesophageal function in normal subjects.

In a double-blind crossover study, lower oesophageal sphincter pressure (LOSP) and distal oesophageal motility were studied in eight healthy volunteers following a single intravenous dose of omeprazole or placebo. Lower oesophageal sphincter pressure was determined before and at intervals up to 120 min after intravenous administration of 40 mg omeprazole or placebo. No effects on LOSP or distal oesophageal motility were observed.

Methaemoglobinaemia produced by phenazopyridine (Pyridium) in a man with chronic obstructive airways disease.

Life threatening methaemoglobinaemia developed after prolonged therapeutic use of phenazopyridine (Pyridium) in a patient with chronic obstructive airways disease. The combination of chronic obstructive airways disease and oxidant drugs (methaemoglobinaemia) may be lethal. The use of phenazopyridine should be abandoned. Certainly there is no indication to use it for more than a few days in any patient.

Salicylate induced exacerbation of ulcerative colitis.

The oral administration of mesalazine (5-aminosalicylic acid) resulted in the exacerbation of ulcerative colitis in two patients intolerant to sulphasalazine whose colitis had previously been quiescent. Although sulphasalazine intolerance is usually attributable to the sulphapyridine moiety, the possibility of salicylate sensitivity should be considered in colitic patients who fail to respond appropriately to sulphasalazine or who experience abdominal pain or diarrhoea while taking the drug.