Design and engineering of water-soluble light-harvesting protein maquettes.

Natural selection in photosynthesis has engineered tetrapyrrole based, nanometer scale, light harvesting and energy capture in light-induced charge separation. By designing and creating nanometer scale artificial light harvesting and charge separating proteins, we have the opportunity to reengineer and overcome the limitations of natural selection to extend energy capture to new wavelengths and to tailor efficient systems that better meet human as opposed to cellular energetic needs. While tetrapyrrole cofactor incorporation in natural proteins is complex and often assisted by accessory proteins for cofactor transport and insertion, artificial protein functionalization relies on a practical understanding of the basic physical chemistry of protein and cofactors that drive nanometer scale self-assembly. Patterning and balancing of hydrophobic and hydrophilic tetrapyrrole substituents is critical to avoid natural or synthetic porphyrin and chlorin aggregation in aqueous media and speed cofactor partitioning into the non-polar core of a man-made water soluble protein designed according to elementary first principles of protein folding. This partitioning is followed by site-specific anchoring of tetrapyrroles to histidine ligands strategically placed for design control of rates and efficiencies of light energy and electron transfer while orienting at least one polar group towards the aqueous phase.

Anal signs of child sexual abuse: a case-control study.

BACKGROUND: There is uncertainty about the nature and specificity of physical signs following anal child sexual abuse. The study investigates the extent to which physical findings discriminate between children with and without a history of anal abuse. METHODS: Retrospective case note review in a paediatric forensic unit. CASES: all eligible cases from 1990 to 2007 alleging anal abuse. CONTROLS: all children examined anally from 1998 to 2007 with possible physical abuse or neglect with no identified concern regarding sexual abuse. Fisher's exact test (two-tailed) was performed to ascertain the significance of differences for individual signs between cases and controls. To explore the potential role of confounding, logistic regression was used to produce odds ratios adjusted for age and gender. RESULTS: A total of 184 cases (105 boys, 79 girls), average age 98.5 months (range 26 to 179) were compared with 179 controls (94 boys, 85 girls) average age 83.7 months (range 35-193). Of the cases 136 (74%) had one or more signs described in anal abuse, compared to 29 (16%) controls. 79 (43%) cases and 2 (1.1%) controls had >1 sign. Reflex anal dilatation (RAD) and venous congestion were seen in 22% and 36% of cases but <1% of controls (likelihood ratios (LR) 40, 60 respectively), anal fissure in 14% cases and 1.1% controls (LR 13), anal laxity in 27% cases and 3% controls (LR 10).Novel signs seen significantly more commonly in cases were anal fold changes, swelling and twitching. Erythema, swelling and fold changes were seen most commonly within 7 days of last reported contact; RAD, laxity, venous congestion, fissure and twitching were observed up to 6 months after the alleged assault. CONCLUSIONS: Anal findings are more common in children alleging anal abuse than in those presenting with physical abuse or neglect with no concern about sexual abuse. Multiple signs are rare in controls and support disclosed anal abuse.

Design, synthesis and biological evaluation of peptide derivatives of L-dopa as anti-parkinsonian agents.

A series of dipeptide derivatives of L-dopa were synthesized and investigated for their pharmacological activity using the unilaterally 6-hydroxydopamine (6-OHDA)-lesioned rat as an experimental model of Parkinson's disease. Among them, (S)-isopropyl 2-(2-amino-2-methylpropanamido)-3-(3,4-dihydroxyphenyl)propanoate (4 g) was found to be the most active compound, with 106% AUC activity and 149% peak activity of L-dopa after oral administration.

Physical evidence of child sexual abuse.

UNLABELLED: Child sexual abuse is increasingly recognised in all societies, affecting boys and girls alike in all age groups and often involving oral, anal and vaginal penetration. The presence of physical evidence following suspected child sexual abuse is important in confirming the diagnosis and providing legal corroboration that abuse has occurred. Whilst many children have no physical evidence, its presence should be carefully sought and documented by skilled examination, regardless of the time interval between any suspected abuse and the examination. When examination is close to the time of the abuse, forensic sampling may be required. Although many children have no physical findings, understanding the significance of physical findings has increased with both experience and research, although certainty and agreement is lacking in some areas. There are few case control studies of abused and non-abused children where standard terminology, examination method and description allow for meaningful comparison. CONCLUSIONS: Physical findings rarely provide conclusive evidence of sexual abuse in isolation but may offer important pieces of the diagnostic "jigsaw picture".

Design, synthesis and biological evaluation of L-dopa amide derivatives as potential prodrugs for the treatment of Parkinson's disease.

A range of amide derivatives of L-dopa were synthesized and investigated for their pharmacological activity and their ability to be converted to L-dopa using the unilaterally 6-hydroxydopamine (6-OHDA)-lesioned rat, as an experimental model of Parkinson's disease. The diacetyl derivative of L-dopa amide (11b) was found to be more active than L-dopa after its oral administration and generated plasma levels of L-dopa in the therapeutic range for an antiparkinsonian effect in man.

Nonaccidental trauma: clinical aspects and epidemiology of child abuse.

Radiologists play a key role in the recognition of child abuse. In the last century, radiologists pioneered the identification of nonaccidental injuries, including fractures and brain injury, and together with colleagues in paediatrics advocated the protection of children from abuse. Prevalence studies in many countries have revealed the widespread and hidden nature of child maltreatment. New and complex forms of abuse, e.g. fabricated or induced illness, have been recognized. Physical abuse affects 7-9% of children in the UK, although fewer suffer the severe or life-threatening injuries seen by radiologists. A high index of suspicion of nonaccidental trauma is required where known patterns of injury or inconsistencies of presentation and history are detected. In many cases the diagnosis is readily made, although some cases remain contentious or controversial and consume much clinical time and energy. Differences of view between doctors are tested in the courts. Adverse publicity has made this work unpopular in the UK. Knowledge of the differential diagnosis of unexplained or apparent injury is essential for accurate diagnosis, vital where errors in either direction can be disastrous. New UK radiological guidelines will assist radiologists in achieving best evidence-based practice.

Structure, dynamics, and binding thermodynamics of the v-Src SH2 domain: implications for drug design.

SH2 domains provide fundamental recognition sites in tyrosine kinase-mediated signaling pathways which, when aberrant, give rise to disease states such as cancer, diabetes, and immune deficiency. Designing specific inhibitors that target the SH2 domain-binding site, however, have presented a major challenge. Despite well over a decade of intensive research, clinically useful SH2 domain inhibitors have yet to become available. A better understanding of the structural, dynamic, and thermodynamic contributions to ligand binding of individual SH2 domains will provide some insight as to whether inhibitor development is possible. We report the first high resolution solution structure of the apo-v-Src SH2 domain. This is accompanied by the analysis of backbone dynamics and pK(a) values within the apo- and peptide-bound states. Our results indicate that the phosphotyrosine (pY) pocket is tightly structured and hence not adaptable to exogenous ligands. On the other hand, the pocket which accommodates residues proximal and C-terminal of the pY (pY + 3) or so-called specificity determining region, is a large dynamic-binding surface. This appears to allow a high level of promiscuity in binding. Binding of a series of synthetic, phosphotyrosyl, peptidomimetic compounds designed to explore interactions in the pY + 3 pocket further demonstrates the ability of the SH2 domain to accommodate diverse ligands. The thermodynamic parameters of these interactions show dramatic enthalpy/entropy compensation. These data suggest that the v-Src SH2 domain does not have a highly specific secondary-binding site, which clearly presents a major hurdle to design selective inhibitors.

Design, synthesis, and antiviral properties of 4'-substituted ribonucleosides as inhibitors of hepatitis C virus replication: the discovery of R1479.

A series of 4'-substituted ribonucleoside derivatives has been prepared and evaluated for inhibition of hepatitis C virus (HCV) RNA replication in cell culture. The most potent and non-cytotoxic derivative was compound 28 (4'-azidocytidine, R1479) with an IC(50) of 1.28 microM in the HCV replicon system. The triphosphate of compound 28 was prepared and shown to be an inhibitor of RNA synthesis mediated by NS5B (IC(50)=320 nM), the RNA polymerase encoded by HCV. Data on related analogues have been used to generate some preliminary requirements for activity within this series of nucleosides.

Synthesis and SAR of novel 2-arylthiazolidinones as selective analgesic N-type calcium channel blockers.

A series of new N-type (Ca(v)2.2) calcium channel blockers derived from the 'hit' structures 2-(3-bromo-4-fluorophenyl)-3-(2-pyridin-2-ylethyl)thiazolidin-4-one 9 and its 2-[4-(4-bromophenyl)pyridin-3-yl]-3-isobutyl analogue 10 is described. Extensive SAR studies using a range of synthetic approaches resulted in novel, patented compounds with IC50 values of up to 0.2 microM in an in vitro IMR32 assay, and selectivities for N/L of up to 30-fold. The new compounds described have potential in treatment of neuropathic pain.

Structure-based design of peptidomimetic antagonists of p56(lck) SH2 domain.

Starting from the tetrapeptide Ac-pYEEI-NHMe and using a structure-based approach, we have designed and synthesised a peptidomimetic ligand for p56(lck) SH2 domain containing a conformationally restricted replacement for the two glutamate residues. We have explored replacments for the isoleucine residue in the pY+3 pocket and thus identified 1-(R)-amino-3-(S)-indaneacetic acid as the most potent replacement. We also report the X-ray crystal structures of two of the antagonists.