Optimizing the Bioavailability of Subcutaneously Administered Biotherapeutics Through Mechanochemical Drivers.

The subcutaneous route offers myriad benefits for the administration of biotherapeutics in both acute and chronic diseases, including convenience, cost effectiveness and the potential for automation through closed-loop systems. Recent advances in parenteral administration devices and the use of additives which enhance drug dispersion have generated substantial additional interest in IV to SQ switching studies. Designing pre-clinical and clinical studies using SQ mediated delivery however requires deep understanding of complex inter-related physiologies and transport pathways governing the interstitial matrix, vascular system and lymphatic channels. This expert review will highlight key structural features which contribute to transport and biodistribution in the subcutaneous space and also assess the impact of drug formulations. Based on the rapidly growing interest in the SQ delivery route, a number of potential areas for future development are highlighted, which are likely to allow continued evolution and innovation in this important area.

Immune focusing and enhanced neutralization induced by HIV-1 gp140 chemical cross-linking.

Experimental vaccine antigens based upon the HIV-1 envelope glycoproteins (Env) have failed to induce neutralizing antibodies (NAbs) against the majority of circulating viral strains as a result of antibody evasion mechanisms, including amino acid variability and conformational instability. A potential vaccine design strategy is to stabilize Env, thereby focusing antibody responses on constitutively exposed, conserved surfaces, such as the CD4 binding site (CD4bs). Here, we show that a largely trimeric form of soluble Env can be stably cross-linked with glutaraldehyde (GLA) without global modification of antigenicity. Cross-linking largely conserved binding of all potent broadly neutralizing antibodies (bNAbs) tested, including CD4bs-specific VRC01 and HJ16, but reduced binding of several non- or weakly neutralizing antibodies and soluble CD4 (sCD4). Adjuvanted administration of cross-linked or unmodified gp140 to rabbits generated indistinguishable total gp140-specific serum IgG binding titers. However, sera from animals receiving cross-linked gp140 showed significantly increased CD4bs-specific antibody binding compared to animals receiving unmodified gp140. Moreover, peptide mapping of sera from animals receiving cross-linked gp140 revealed increased binding to gp120 C1 and V1V2 regions. Finally, neutralization titers were significantly elevated in sera from animals receiving cross-linked gp140 rather than unmodified gp140. We conclude that cross-linking favors antigen stability, imparts antigenic modifications that selectively refocus antibody specificity and improves induction of NAbs, and might be a useful strategy for future vaccine design.

Designed enediyne antitumor agents.

The enediynes remain among the most potent antitumoral agents to have been discovered in the past decade. Following prodrug activation, the enediynes undergo cycloaromatization reactions resulting in formation of highly reactive diradical intermediates. The diradical species engage in atom-transfer chemistry to produce neutral arene products, in the process inducing damage to key macromolecules. Several of the naturally occurring members of the enediyne family of antibiotics have entered clinical trials, and this has prompted the design of synthetic enediynes, where the enediyne lquo;warheadrquo; is conjugated to a targeted delivery vehicle. This review will describe ecent efforts using chemical synthesis to identify and improve the target specificity of designed enediynes, and to establish efficient methods to achieve prodrug activation. Finally, new horizons will be examined, including the use of post-cycloaromatized enediyne templates as recognition elements for unique DNA and RNA microenvironments.

Electronic control of the Bergman cycloaromatization: synthesis and chemistry of chloroenediynes.

[reaction: see text] A series of cyclic mono- and dichloroenediynes have been prepared using an intramolecular carbenoid coupling reaction. The halogen atom had a retardative effect on Bergman cycloaromatization in every case examined, and atom transfer chemistry was demonstrated, resulting in formation of adducts.

Understanding enediyne-protein interactions: diyl atom transfer results in generation of aminoacyl radicals.

[formula: see text] The origin of the protein modulating capacity of enediynes has been probed. A series of synthetic enediyne-derived diyls participated in atom transfer chemistry with a labeled amino acid. Subsequent experiments suggest that diyl radicals may modulate protein architecture via formation of captodatively stabilized radicals.

Protein-degrading enediynes: library screening of Bergman cycloaromatization products.

[structure: see text] A screening method based on Bergman cycloaromatization products was applied to a compact library of estrogenic-enediyne hybrids. An enediyne candidate identified from the screen was subsequently synthesized, and it induced temperature- and concentration-dependent degradation of human estrogen receptor alpha upon cycloaromatization.

Synthesis and DNA binding of spirocyclic model compounds related to the neocarzinostatin chromophore.

[formula: see text] Spirocyclic model compounds which mimic the molecular architecture of one of the decomposition products of the antitumor agent NCS-chrom have been synthesized. These readily accessible molecules bind with remarkable efficiency to bulged DNA oligonucleotides, offering potential for the design of therapeutic agents.

Precision stereotaxic procedure for the mouse (Mus musculus): method and instrumentation.

A precision stereotaxic procedure for mouse brain research is described accompanied by a new design in mouse stereotaxic head holder and a new device used to guarantee accurate alignment of the skull in the stereotaxic device. This method and instrumentation when applied in forthcoming research will contribute to the development of investigations of structure/function relationship in mouse brain.

New approaches to pyrrolo[2,1-c][1,4]benzodiazepines: synthesis, DNA-binding and cytotoxicity of DC-81.

Two routes to the naturally occurring DNA-binding antitumour antibiotic DC-81 are described, one of which involves a novel cyclization process based on acid resin. The second route involves the synthesis of a new compound, 6-nitrovanillic acid, a key A-ring component of many naturally occurring PBDs. These routes have provided a sufficient quantity of DC-81 to allow complete characterization and evaluation in DNA-binding and in vitro cytotoxicity studies.

Stressful events among pregnant Salvadoran women: a cross-cultural comparison.

OBJECTIVE: To compare stressful events, including violent episodes, experienced by pregnant Salvadoran women with those experienced by two other groups of low-income, pregnant women living in the United States (non-Salvadoran Hispanics and non-Hispanics) and to examine the association between episodes of violence and drug or alcohol use among the three groups. DESIGN: Comparative, descriptive study. SETTING: Public health prenatal clinics. PARTICIPANTS: One hundred four Salvadoran, 69 non-Salvadoran Hispanic, and 187 non-Hispanic pregnant women. MAIN OUTCOME MEASURES: Difficult Life Circumstances (DLC) scale and psychosocial history assessment. RESULTS: Statistically significant differences were found among the three groups in total DLC scores, F(2, 357) = 14.98, p < .001; reported episodes of violence, F(2, 357 = 17.82, p < .001; and drug or alcohol use, F(2, 357) = 6.33, p < .001. A significant difference was found to the extent that alcohol or drug use accounted for the variance in violence among the three groups, F(3, 360) = 6.28, p < .001. CONCLUSIONS: Cross-cultural comparisons revealed group differences in the number of stressful events, including episodes of violence and alcohol or drug use.

PIP: A comparative, descriptive study was conducted among 104 Salvadoran, 69 non-Salvadoran Hispanic, and 187 non-Hispanic pregnant women concerning the stressful events including episodes of violence experienced. Furthermore, it also compared the relationship between episodes of violence and drug or alcohol use among the three groups. The measures used are the Difficult Life Circumstances scale and psychosocial history assessment. Results showed that stressful events were found to occur more frequently among the non-Hispanic mothers than among either Hispanic subgroups. However, cultural distinctions between Salvadoran and non-Salvadoran Hispanic mothers did not emerge. Alcohol and drug use differed significantly among the groups in this study. In conclusion, cross-cultural comparisons revealed group differences in the number of stressful events, including episodes of violence and alcohol or drug use.

ENCORE: the effect of nutrient enrichment on coral reefs. Synthesis of results and conclusions.

Coral reef degradation resulting from nutrient enrichment of coastal waters is of increasing global concern. Although effects of nutrients on coral reef organisms have been demonstrated in the laboratory, there is little direct evidence of nutrient effects on coral reef biota in situ. The ENCORE experiment investigated responses of coral reef organisms and processes to controlled additions of dissolved inorganic nitrogen (N) and/or phosphorus (P) on an offshore reef (One Tree Island) at the southern end of the Great Barrier Reef, Australia. A multi-disciplinary team assessed a variety of factors focusing on nutrient dynamics and biotic responses. A controlled and replicated experiment was conducted over two years using twelve small patch reefs ponded at low tide by a coral rim. Treatments included three control reefs (no nutrient addition) and three + N reefs (NH4Cl added), three + P reefs (KH2PO4 added), and three + N + P reefs. Nutrients were added as pulses at each low tide (ca twice per day) by remotely operated units. There were two phases of nutrient additions. During the initial, low-loading phase of the experiment nutrient pulses (mean dose = 11.5 microM NH4+; 2.3 microM PO4(-3)) rapidly declined, reaching near-background levels (mean = 0.9 microM NH4+; 0.5 microM PO4(-3)) within 2-3 h. A variety of biotic processes, assessed over a year during this initial nutrient loading phase, were not significantly affected, with the exception of coral reproduction, which was affected in all nutrient treatments. In Acropora longicyathus and A. aspera, fewer successfully developed embryos were formed, and in A. longicyathus fertilization rates and lipid levels decreased. In the second, high-loading, phase of ENCORE an increased nutrient dosage (mean dose = 36.2 microM NH4+; 5.1 microM PO4(-3)) declining to means of 11.3 microM NH4+ and 2.4 microM PO4(-3) at the end of low tide) was used for a further year, and a variety of significant biotic responses occurred. Encrusting algae incorporated virtually none of the added nutrients. Organisms containing endosymbiotic zooxanthellae (corals and giant clams) assimilated dissolved nutrients rapidly and were responsive to added nutrients. Coral mortality, not detected during the initial low-loading phase, became evident with increased nutrient dosage, particularly in Pocillopora damicornis. Nitrogen additions stunted coral growth, and phosphorus additions had a variable effect. Coral calcification rate and linear extension increased in the presence of added phosphorus but skeletal density was reduced, making corals more susceptible to breakage. Settlement of all coral larvae was reduced in nitrogen treatments, yet settlement of larvae from brooded species was enhanced in phosphorus treatments. Recruitment of stomatopods, benthic crustaceans living in coral rubble, was reduced in nitrogen and nitrogen plus phosphorus treatments. Grazing rates and reproductive effort of various fish species were not affected by the nutrient treatments. Microbial nitrogen transformations in sediments were responsive to nutrient loading with nitrogen fixation significantly increased in phosphorus treatments and denitrification increased in all treatments to which nitrogen had been added. Rates of bioerosion and grazing showed no significant effects of added nutrients. ENCORE has shown that reef organisms and processes investigated in situ were impacted by elevated nutrients. Impacts were dependent on dose level, whether nitrogen and/or phosphorus were elevated and were often species-specific. The impacts were generally sub-lethal and subtle and the treated reefs at the end of the experiment were visually similar to control reefs. Rapid nutrient uptake indicates that nutrient concentrations alone are not adequate to assess nutrient condition of reefs. Sensitive and quantifiable biological indicators need to be developed for coral reef ecosystems. The potential bioindicators identified in ENCORE should be tested in future research on coral reef/nutrient interactions. Synergistic and cumulative effects of elevated nutrients and other environmental parameters, comparative studies of intact vs. disturbed reefs, offshore vs. inshore reefs, or the ability of a nutrient-stressed reef to respond to natural disturbances require elucidation. An expanded understanding of coral reef responses to anthropogenic impacts is necessary, particularly regarding the subtle, sub-lethal effects detected in the ENCORE studies.

Assessing infant health promotion: a cross-cultural comparison.

The purpose of this cross-cultural, correlational study was to evaluate two popular clinical/research assessment tools, the NCAST Teaching Scale and the Home Observation Measurement of the Environment (HOME) Inventory, as measures of infant health promotion behaviors for low-income, foreign-born Hispanic mothers in the United States. Based on the assumption that both measures tap universal attributes of the mother-infant relationship, it was hypothesized that maternal performance for the study group and a comparison group of U.S.-born, low-income mothers would be similar. Comparable performance on the NCAST Teaching Scale included a full range of scores, including the capacity to identify mothers most in need of clinical intervention. Study fundings supported the clinical use of this assessment scale with mothers represented by the study sample. Consistently lower scores by the foreign-born Hispanic mothers on the HOME Inventory led to the conclusion that the instrument may not tap cultural universals in the mother-infant relationship.

Towards next generation adenosine A(2A) receptor antagonists.

The Adenosine A2A receptor is a member of the G-protein coupled receptor superfamily. It plays a key role in numerous physiological processes through the central nervous system and in peripheral tissues. Functional interactions between the A2A and dopamine D2 receptor has spurred interest in the use of antagonists as anti-Parkinson drugs. Additionally, oncology drugs are now being designed based on the potential for A2A antagonists to function as immunotherapeutics. From early studies based on classical xanthine type A2A antagonists through second generation agents, this mini review will cover aspects of the discovery, development, chemical synthesis and medicinal evaluation of this important class of drugs.

Microwave accelerated synthesis of PET image contrast agents for AD research.

Positron emission tomography (PET) imaging of Alzheimer's Disease (AD) offers the potential to provide early onset diagnosis and subsequent intervention, including guided treatment regimens. One of the restricting factors in clinical application of PET technology is the limited availability of radioligands with affinity to specific targets of interest. Given the short half-life of the most popular positron emitter currently used ((18)F; approximately 120 min.) extremely rapid and efficient radiochemistry methods are needed to ensure required compounds are prepared and purified for administration within the 2-3 half life practical limit. Recent efforts to combine microwave mediated synthesis with advanced catalysis in the synthesis of specific categories of AD imaging agents will be presented.