Interauterine Transfusion: 101 Consecutive Cases treated at Queen Charlotte's Maternity Hospital

Intrauterine transfusion was performed or attempted in 101 cases during a period of four and a half years. After exclusion of six cases, for reasons detailed in the text, 95 cases are considered in detail. Intrauterine transfusion was successfully performed in 93 of these, with a mean of 2·8 transfusions each. Forty-four babies (46·3%) survived and all but one are so far developing normally.     

Heterocyclic analogues of L-citrulline as inhibitors of the isoforms of nitric oxide synthase (NOS) and identification of N(delta)-(4,5-dihydrothiazol-2-yl)ornithine as a potent inhibitor.

L-Thiocitrulline is a known potent inhibitor of several isoforms of nitric oxide synthase (NOS). To explore the structure-activity relationships (SARs) for this molecule in more depth than has previously been reported, three analogues substituted at the sulphur of the isothioureas have been synthesised. In two of these, the S-substituent was 'tied back' sterically by cyclisation to the nitrogen remote from the amino-acid unit. N(delta)-(4,5-Dihydrothiazol-2-yl)ornithine was identified as an inhibitor of rat inducible and constitutive isoforms of NOS and of a constitutive NOS derived from a human tumour xenograft. Analogous N(delta)-(thiazol-2-yl)ornithines were less active, whereas the corresponding N(delta)-(oxazol-2-yl)ornithine and N(delta)-(pyrimidin-2-yl)ornithine failed completely to inhibit NOS. A new efficient preparation of the critical synthetic intermediate, N(alpha)-Boc-thiocitrulline t-butyl ester, has been developed. Further exploration of the SAR with 2-amino-5-(heterocyclylthio)pentanoic acids (synthesised from 2-(Boc-amino)-5-bromopentanoic acid t-butyl ester), with N-(4-aminobutyl)thiourea and with 2-(4-aminobutylamino)-4,5-dihydrothiazole enabled refinement of our previous model for binding of the substrate, L-arginine, and the inhibitors to NOS.     

Adsorption of ethylenediaminetetraacetic dianhydride modified oxalate decarboxylase on calcium oxalate

We used ethylenediaminetetraacetic acid dianhydride (EDTAD) to modify oxalate decarboxylase (OXDC) to improve its adsorption on calcium oxalate stones. The modified sites were identified by Ultra performance liquid chromatography-mass spectrometry (UPLC-MS) and the adsorption mechanism of the EDTAD-modified OXDC on calcium oxalate (CaOx) was investigated. We investigated adsorption time, initial enzyme concentration, temperature and solution pH on the adsorption process. Data were analyzed using kinetics, thermodynamics and isotherm adsorption models. UPLC-MS showed that EDTAD was attached to OXDC covalently and suggested that the chemical modification occurred at both the free amino of the side chain and the α-NH₂ of the peptide. The adsorption capacity of the EDTAD-OXDC on calcium oxalate was 53.37% greater than that of OXDC at the initial enzyme concentration of 5 mg/ml, pH = 7.0, at 37° C. The modified enzyme (EDTAD-OXDC) demonstrated improved oxalate degradation activity at pH 4.5?6.0. Kinetic data fitting analysis suggested a pseudo second order kinetic model. Estimates of the thermodynamic parameters including ΔG⁰, ΔH⁰ and ΔS⁰ of the adsorption process showed it to be feasible, spontaneous and endothermic. Isotherm data fitting analysis indicated that the adsorption process is reduced to monolayer adsorption at a low enzyme concentration and to multilayer adsorption at a high enzyme concentration. It may be possible to apply OXDC to degradation of calcium oxalate stones.     

Discovery of super soft-drug modulators of sphingosine-1-phosphate receptor 1

The oral S1PR1 agonist ponesimod demonstrated substantial efficacy in a phase II clinical trial of psoriasis. Unfortunately, systemic side effects were observed, which included lymphopenia and transient bradycardia. We sought to develop a topical soft-drug S1PR1 agonist with an improved therapeutic index. By modifying ponesimod, we discovered an ester series of S1PR agonists. To increase metabolic instability in plasma we synthesised esters described as specific substrates for paraoxonase and butyrylcholinesterases, esterases present in human plasma.