The crystal structures of 2,5-piperazinediones having epipolysulfide bridges between c3 and c6: the structures of n,n'-dimethyl-3,6-epitetrathio-2,5-piperazinedione

The crystal and molecular structure of N,N'-dimethyl-3,6-epitetrathio-2,5-piperazinedione (C(6)H(8)O(2)N(2)S(4)) has been determined from three-dimensional x-ray diffraction data collected by counter techniques. The substance crystallizes in the orthorhombic space group Fdd2, with a = 15.352(5), b = 20.432(7), and c = 6.635(2) A; V = 2081.2(8) A(3), D(meas) = 1.72(2) g/cm(3), and z = 8 molecules per unit cell. The molecule lies on a crystallographic 2-fold axis, the piperazinedione ring is in the boat conformation, and the deviation from planarity is 18 degrees . The bonds of the tetrasulfide chain alternate in length so that the S-S distances are 2.0244(9), 2.076(1), and 2.0244(9) A. The structural data were refined by least-squares methods to an R(F) of 2.5% by use of the 1089 independent reflections (2theta </= 71 degrees ; MoKalpha) for which F(0) (2) >/= 3sigma (F(0) (2)). Since this molecule is chemically identical with the active center of the recently isolated natural product sporidesmin G, our structural study constitutes a description of the epitetrathio-2,5-piperazinedione fragment of that molecule.

Neutron diffraction structure of melampodin: its role in the reclassification of the germacranolides

The precise crystal and molecular structure of melampodin, C(21)H(24)O(9), was determined from three-dimensional neutron diffraction data collected by counter techniques and phases by direct statistical methods. Crystals are orthorhombic, P2(1)2(1)2(1), a = 8,990(9), b = 14.352(14), c = 16.294(16) A, V = 2102 A(3), d(calc.) = 1.328 g.cm(-3), Z = 4 molecules per unit cell. The structural model was refined by full matrix least-squares of 2303 observed independent reflections, with all 54 atoms treated anisotropically, to R(F) = 5.0%. Hydrogen bonds link melampodin molecules together in the solid state. The conformation of the cyclodeca-1,5-diene ring is such that one intraannular hydrogen atom interacts strongly with one double bond, but there is little or no transannular interaction between double bonds. Strain in the ten-membered ring and in the trans-fused lactone ring is discussed, as are chemical implications of the unsymmetric epoxide in the epoxyangelic acid side chain. The previously suggested reclassification of germacranolide sesquiterpene lactones into four subgroups is supported, and a new convention for configurational representations of the four subgroups is proposed.

Infliximab safety profile and long-term applicability in inflammatory bowel disease: 9-year experience in clinical practice

BACKGROUND

Most available data on infliximab therapy come from large, short-term, pivotal RCTs and concerns about long-term safety profile still remain.

AIM

To evaluate the long-term safety profile of infliximab in inflammatory bowel disease (IBD) in a clinical practice setting.

METHODS

Since 1999, all IBD patients treated with infliximab were registered and clinical outcomes prospectively recorded up to March 2008, loss of follow-up or patient's death. Infliximab regimens and preventive measures were in accordance with the prevalent guidelines or with the manufacturer's recommendations.

RESULTS

One hundred fifty-two patients were included (121 Crohn's disease, 24 ulcerative colitis, 7 indeterminate colitis), with a median of 5 infliximab infusions (IQR 3-8) and 87% of patients received at least three infusions. Seventy-nine per cent of them received concomitant immunomodulators and 70% were pre-medicated with hydrocortisone from the first infusion. After a median follow-up of 142 weeks, 13% presented infusion reactions, 13% viral or bacterial infections and two patients developed neoplasia. The mortality rate was 2.6% (four patients).

CONCLUSIONS

Infliximab therapy is safe when the recommended preventive measures are implemented, with a rate of serious adverse events less than 10%. No new safety signals were found.

The structure of Co(NH3)6CuCl5 at 10 K

The structure of the title compound was determined at 10 K using the Fddd diffractometer equipped with a Mo-target rotating anode. The object of the study was to determine the geometrical parameters of the cation and anion at what we assume is their resting state geometry, given the temperature of data collection. The cation is es-sentially unchanged in geometry from 294 K to 10 K. The anion is considerably distorted, having changed from a trigonal bipyramid (site symmetry 32) to a “T-shaped” or “seesaw” structure, sitting at a two-fold axis. During the cooling process, the space group changed from Fd3̅c to F41/adc. The shape of the anion is, interestingly, similar to that of XeO2F2.

Clinical evolution of luminal and perianal Crohn's disease after inducing remission with infliximab: how long should patients be treated?

BACKGROUND

Few data are available regarding the evolution of Crohn's disease after discontinuing a successful course of infliximab.

AIM

To evaluate clinical outcome of Crohn's disease after induction of remission with three infliximab infusions (luminal disease) and after maintenance of remission with 1-year course of infliximab every 8 weeks (luminal and perianal).

METHODS

Twenty-three patients with active luminal Crohn's disease who responded to three infusions of infliximab (0, 2, and 6 weeks), and 23 patients with sustained response to infliximab every 8 weeks during 1 year, were included. Patients were followed-up until relapse or for at least 6 months after infliximab discontinuation. Clinical outcomes and factors associated to relapse were evaluated.

RESULTS

In luminal Crohn's disease, a three-infusion infliximab regimen achieved a sustained response in most patients, especially if a complete response occurred at the time of the third infusion. In patients treated for 1-year, infliximab discontinuation was also successful, with a cumulative probability of being free of relapse of 69% at 12 months. In perianal disease, early relapse was the rule after stopping infliximab treatment, with only 34% of patient maintaining remission at 1 year.

CONCLUSIONS

Short regimens of infliximab might be evaluated in patients with luminal Crohn's disease. However, infliximab discontinuation is not recommended in perianal Crohn's disease, because of a high rate of early relapse.

Increased plasma levels of TNF-α but not of IL1-β in MPTP-treated monkeys one year after the MPTP administration

The cause of Parkinson's disease remains unknown although some evidence suggests that an inflammatory reaction, mediated by cytokines such as TNF-alpha and IL-1beta, is related with dopaminergic degeneration in the brain. In the present work we measured the plasma levels of TNF-alpha and IL-1beta in parkinsonian monkeys one year after MPTP administration. TNF-alpha levels were seen to have increased in parkinsonian monkeys reflecting the clinical symptoms observed, while IL-1beta levels remained unchanged. These results suggest that TNF-alpha plays a role in sustaining of dopaminergic degeneration in chronic parkinsonism.

Anemia hemolítica autoinmune asociada a colitis ulcerosa

The incidence of immunological disorders has been reported to be greater in patients with inflammatory bowel disease than among the general population. The association of ulcerative colitis (UC) and autoimmune hemolytic anemia (AIHA) was first described in the early 1950s but no more than 50 cases have been described in the international literature. Detailed description of the pathogenic mechanisms involved in this association is lacking. The clinical course of AIHA and treatment response in these patients seems to be independent of UC, sometimes requiring immunosuppressive treatment and even surgery. We present 2 cases of AIHA associated with UC with distinct response to conventional treatment. We also review the literature on the subject.

Azatioprina y mesalazina en la prevención de la recurrencia posquirúrgica en la enfermedad de Crohn: estudio retrospectivo

OBJECTIVES

Surgical resection is still a mainstay of the treatment of Crohn's disease (CD). However, recurrence is the rule. The aim of the present study was to evaluate CD recurrence in a series of patients who underwent surgical resection with subsequent treatment with azathioprine (AZA) or mesalazine (5-ASA) and to identify the factors associated with recurrence.

METHODS

The medical records of patients with CD who underwent bowel resection during a 4-year period were reviewed. Only patients who received AZA or 5-ASA as prophylaxis for recurrence were included.

RESULTS

Thirty-three patients treated with AZA and 16 treated with 5-ASA were included. Endoscopic recurrence was found in 8.6% of the AZA group and in 87.5% of the 5-ASA group (p <0.001). Clinical recurrence occurred in 31.2% of patients in the 5-ASA group and in none in the AZA group (p=0.004). The accumulated probability of both clinical and endoscopic recurrence was significantly lower in the AZA group (p=0.0025 and p=0.005, respectively). Factors associated with a greater risk of endoscopic recurrence were termino-terminal anastomosis and 5-ASA treatment. The only factor associated with clinical recurrence was 5-ASA treatment.

CONCLUSION

AZA seems to be more effective than 5-ASA in the prevention of postsurgical endoscopic recurrence of CD. Prospective studies with long-term follow-up are required to establish the true utility of AZA in the prophylaxis of CD recurrence.

[Opportunistic infections in patients with inflammatory bowel disease undergoing immunosuppressive therapy]

Immunosuppressive agents (azathioprine, methotrexate) are increasingly being used in the treatment of inflammatory bowel disease. The use of immunosuppressive agents is associated with a greater risk of opportunistic infections, the most frequent of which are those caused by cytomegalovirus and varicella zoster virus. We present four cases of opportunistic infections due to Herpesviruses in patients undergoing immunosuppressive treatment with azathioprine for Crohn's disease. We also review the literature published on this topic. Two patients presented cutaneous varicella complicated by pneumonia and esophagitis respectively, one patient had cutaneous herpes zoster and the other had fatal pneumonia possibly caused by the Herpesvirus. In the first three the clinical course of the infection was favorable after withdrawing immunosuppressant treatment and initiating treatment with aziclovir. In patients Crohn's disease azathioprine treatment increases the risk of opportunistic infection by Herpesvirus. However, in the absence of other factors that increase immunosuppression, these infections usually have a benign course with specific antiviral therapy.

Azathioprine without oral ciclosporin in the long-term maintenance of remission induced by intravenous ciclosporin in severe, steroid-refractory ulcerative colitis

BACKGROUND

Intravenous ciclosporin is considered to be the only alternative to avoid surgery in severe, steroid-refractory ulcerative colitis. In responders, some authors recommend a switch to oral ciclosporin to act as a 'bridge' until the therapeutic action of azathioprine is achieved for maintenance treatment.

AIM

To report the short- and long-term outcome of intravenous ciclosporin-responsive ulcerative colitis patients treated with oral azathioprine without oral ciclosporin.

METHODS

The records of all patients treated with intravenous ciclosporin for severe, steroid-refractory ulcerative colitis were reviewed. Responders following treatment with azathioprine but without oral ciclosporin as maintenance therapy were included. Patients with colonic cytomegalovirus infection and/or follow-up of less than 1 year were excluded.

RESULTS

Twenty-seven patients were included. Steroids were discontinued in 24 (89%). The median follow-up was 36 months. Eighteen (75%) patients presented mild or moderate relapses, which were easily managed with salicylates or steroids. Cumulative probabilities of relapse were 42%, 72% and 77% at 1, 3 and 5 years, respectively. Eleven (40.7%) patients underwent elective colectomy. Cumulative probabilities of colectomy were 29%, 35% and 42% at 1, 3 and 5 years, respectively. No opportunistic infections were observed.

CONCLUSIONS

Oral azathioprine seems to be enough to maintain long-term remission induced by intravenous ciclosporin in patients with steroid-refractory ulcerative colitis. The 'bridging step' with oral ciclosporin may not be necessary in this subset of patients, although a randomized controlled trial is warranted to confirm this hypothesis.

Triazidocobalt(III) complexes with tridentate amine ligands

The title compounds, [N-(2-aminoethyl)-1, 3-propanediamine-kappa(3)N]triazidocobalt(III), [Co(N(3))(3)(C(5)H(15)N(3))], [N-(2-aminoethyl)-N-methyl-1, 3-propanediamine-kappa(3)N]triazidocobalt(III), [Co(N(3))(3)(C(6)H(17)N(3))], [N-(2-aminopropyl)-1, 3-propanediamine-kappa(3)N]triazidocobalt(III), [Co(N(3))(3)(C(6)H(17)N(3))], and [N-(2-aminopropyl)-N-methyl-1, 3-propanediamine-kappa(3)N]triazidocobalt(III), [Co(N(3))(3)(C(7)H(19)N(3))], each consist of a Co(III) atom, three azide ligands in a meridional configuration and a tridentate amine ligand, namely aepn [N-(2-aminoethyl)-1,3-propanediamine] or dpt [N-(3-aminopropyl)-1,3-propanediamine], or their N-methylated analogs.

Passive immunization with a human immunodeficiency virus type 1-neutralizing monoclonal antibody in Hu-PBL-SCID mice: isolation of a neutralization escape variant

A monoclonal antibody (694/98-D) directed toward the V3 loop of human immunodeficiency virus type 1 (HIV-1) was evaluated for pre- and postexposure prophylaxis in SCID mice reconstituted with human peripheral blood lymphocytes (Hu-PBL-SCID). Fifty percent protection against the HIV-1LAI strain was obtained by preexposure administration of 1.32 mg/kg antibody. However, virus isolated from 1 mouse 3 weeks after passive immunization with 13.2 mg/kg antibody proved resistant to subsequent in vitro neutralization by 694/98-D. V3 loop sequence analysis of cloned virus revealed amino acid changes within the linear core epitope recognized by 694/98-D and in one flanking amino acid. Further evaluation of 694/98-D for postexposure prophylaxis in mice revealed that 694/ 98-D was effective when given 15 min after virus. However, efficacy declined to 50% if treatment was delayed to 1 h after virus inoculation. These studies point out some potential drawbacks of passive immunization with monoclonal antibodies.

The absolute configuration of Λ-[Co(sen)] [(R,R)(+)tart] C1.6H2O and of Δ-[Co(sen)] [(R,R)(+)tart] C1.4. 5H2O (sen is 5-Methyl-5-(4-amino-2-azabutyl)-3,7-diazanonane-1,9-diamine): A comment on the mode of chiral resolutions by (R,R)(+)Tartrate on the antipodal cations of cobalt(III) salts

The X-ray crystal structures of the Λ and ∆ diastereoisomeric pair of [Co(sen)] [(R,R)(+)tart] ClnH2O (sen is 5-methyl-5-(4-amino-2-azabutyl)-3,7-diazanonane-1,9-diamine, tart is tartrate) have been determined. Crystals of the less soluble Λ isomer, (Λ-(1); n = 6), are othorhombic, space group P212121, with a 10.817(8), b 13.626(8), c 17.724(6) �, while those of the non-preferred Λ isomer, (Λ-(1); n = 4.5), are monoclinic, space group P21, with a 9,469(8), b 12.116(9), c 12.132(7) �, β 95.94(6)�. Both structures were solved by the Patterson method, and refined to R 3.8% (Λ-(1)) and 10.8% (Λ-(1)). In ∆-(1) the waters of hydration are partly disordered in the unit cell. Both crystal structures exhibit extensive hydrogen bonding; however, the mode of contact between the cation and the tartrate dianion in the two compounds is slightly different. In Λ-(1) the three amino hydrogens involved each have only one close contact to a tartrate oxygen, whereas in ∆-(1) each hydrogen has two close contacts. The mode of chiral resolution thus seems to depend on the strength of the hydrogen bonding found in this 'local block', and not simply on its ability to form such a block, since both enantiomers do so.