Organosilica nanoparticles containing sodium borocaptate (BSH) provide new prospects for boron neutron capture therapy (BNCT): efficient cellular uptake and enhanced BNCT efficacy

Boron neutron capture therapy (BNCT), a method based on the fission of boron-10 upon neutron irradiation, has emerged as an attractive option for radiation therapy. To date, the main drugs used in BNCT are 4-boronophenylalanine (BPA) and sodium borocaptate (BSH). While BPA has been extensively tested in clinical trials, the use of BSH has been limited, mainly due to its poor cellular uptake. Here, we describe a novel type of mesoporous silica-based nanoparticle containing BSH covalently attached to a nanocarrier. Synthesis and characterization of these nanoparticles (BSH-BPMO) are presented. The synthetic strategy involves a click thiol-ene reaction with the boron cluster, providing hydrolytically stable linkage with the BSH in four steps. The BSH-BPMO nanoparticles were efficiently taken up into cancer cells and accumulated in the perinuclear region. Inductively coupled plasma (ICP) measurements of boron uptake in cells highlight the important role of the nanocarrier in the enhancement of boron internalization. BSH-BPMO nanoparticles were also taken up and distributed throughout tumour spheroids. BNCT efficacy was examined by the neutron exposure of the tumour spheroids. BSH-BPMO loaded spheroids were completely destroyed upon neutron irradiation. In contrast, neutron irradiation of tumour spheroids loaded with BSH or BPA resulted in significantly less spheroid shrinkage. The significant difference in BNCT efficacy of the BSH-BPMO was correlated with the improved boron uptake via the nanocarrier. Overall, these results demonstrate the critical role of the nanocarrier in BSH internalization and the enhanced BNCT efficacy of the BSH-BPMO compared with BSH and BPA, two drugs used in BNCT clinical trials.

Mesoporous organosilicas with thiol functionalised pores: multifunctional dendrimers as sacrificial building block and template

The synthesis of multifunctional poly(amidoamine) (PAMAM)-based dendrimers containing a cleavable disulfide linker within each arm of the dendrimer, together with condensable triethoxysilyl groups on the periphery of the dendrimer, is described. The dendrimers were mixed with 1,4-bis(triethoxysilyl)benzene and subsequently transformed into silsesquioxane gels or periodic mesoporous organosilicas (PMOs) to generate materials with dendrimers covalently embedded within the interior of the silsesquioxane networks. Subsequent treatment of the gels with dithiothreitol enabled the core of the dendrimers to be selectively cleaved at the disulfide site, thus generating thiol functions localised within the pores. The effect of different dendrimer generations on the reactivity of the pendant thiol functions was probed by impregnation with gold salts, which were reduced to obtain gold nanoparticles within the pore networks of the gels and PMOs. The gels yielded polydisperse gold nanoparticles (2 to 70 nm) with dimensions modulated by the generation of the dendrimer, together with well-defined gold/thiolate clusters with Au⋯S distances of 2.3 Å. Such clusters were also observed in the PMO system, together with monodispersed gold nanoparticles with diameters comparable to that of the organised pores in the PMO. The role of surface functionalisation in controlling the formation of gold clusters and/or nanoparticles is discussed.

Construction of Boronophenylalanine-Loaded Biodegradable Periodic Mesoporous Organosilica Nanoparticles for BNCT Cancer Therapy

Biodegradable periodic mesoporous organosilica (BPMO) has recently emerged as a promising type of mesoporous silica-based nanoparticle for biomedical applications. Like mesoporous silica nanoparticles (MSN), BPMO possesses a large surface area where various compounds can be attached. In this work, we attached boronophenylalanine (¹⁰BPA) to the surface and explored the potential of this nanomaterial for delivering boron-10 for use in boron neutron capture therapy (BNCT). This cancer therapy is based on the principle that the exposure of boron-10 to thermal neutron results in the release of α-particles that kill cancer cells. To attach ¹⁰BPA, the surface of BPMO was modified with diol groups which facilitated the efficient binding of ¹⁰BPA, yielding ¹⁰BPA-loaded BPMO (¹⁰BPA-BPMO). Surface modification with phosphonate was also carried out to increase the dispersibility of the nanoparticles. To investigate this nanomaterial’s potential for BNCT, we first used human cancer cells and found that ¹⁰BPA-BPMO nanoparticles were efficiently taken up into the cancer cells and were localized in perinuclear regions. We then used a chicken egg tumor model, a versatile and convenient tumor model used to characterize nanomaterials. After observing significant tumor accumulation, ¹⁰BPA-BPMO injected chicken eggs were evaluated by irradiating with neutron beams. Dramatic inhibition of the tumor growth was observed. These results suggest the potential of ¹⁰BPA-BPMO as a novel boron agent for BNCT.

Large Polyhedral Oligomeric Silsesquioxane Cages: The Isolation of Functionalized POSS with an Unprecedented Si18 O27 Core

The synthesis of organo-functionalized polyhedral oligomeric silsesquioxanes (POSS, (R-SiO_1.5 )_n , T_n ) is an area of significant activity. To date, T₁₄ is the largest such cage synthesized and isolated as a single isomer. Herein, we report an unprecedented, single-isomer styryl-functionalized T₁₈ POSS. Unambiguously identified among nine possible isomers by multinuclear solution NMR (¹ H, ¹³ C, and ²⁹ Si), MALDI-MS, FTIR, and computational studies, this is the largest single-isomer functionalized T_n compound isolated to date. A ring-strain model was developed to correlate the ²⁹ Si resonances with the number of 6-, 5-, and/or 4-Si-atom rings that each non-equivalent Si atom is part of. The model successfully predicts the speciation of non-equivalent Si atoms in other families of T_n compounds, demonstrating its general applicability for assigning ²⁹ Si resonances to Si atoms in cage silsesquioxanes and providing a useful tool for predicting Si-atom environments.

Functionalised polyhedral oligomeric silsesquioxane with encapsulated fluoride - first observation of fluxional SiF interactions in POSS

The synthesis of a styryl functionalised POSS incorporating an encapsulated fluoride ion within a (SiO_1.5)₈ cage (T₈-F) is reported. It was characterised by single crystal XRD, MALDI-MS, FTIR, solution (²⁹Si, ¹⁹F, ¹³C, ¹H) and solid state (²⁹Si, ¹⁹F) NMR. In the absence of ¹H decoupling, the ²⁹Si solution NMR spectrum exhibited a triplet of doublets. In contrast, ¹H, ¹⁹F and ¹H/¹⁹F double-decoupling resulted in two, three and one signal, respectively, being consistent with a single Si site whose ²⁹Si NMR signal is modulated by both the proximal aromatic-ring protons and fluoride. The associated SiF coupling constant (2.5 Hz) is substantially lower than expected for a covalent Si-F bond and arises from a fluxional SiF covalent effect in which the F^- interacts equivalently with all eight Si atoms. Additional variable temperature NMR studies demonstrated a threshold at -5 °C below which no SiF interactions are observed, and above which an increasing SiF covalent character occurs.

Post-synthesis modification of functionalised polyhedral oligomeric silsesquioxanes with encapsulated fluoride – enhancing reactivity of T8-F POSS for materials synthesis

The first successful approach for modifying poorly reactive POSS containing F⁻ (T₈-F) and incorporating intact T₈-F within a nanohybrid material is described.

Modulatory effects of TGF-β1 and BMP6 on thecal angiogenesis and steroidogenesis in the bovine ovary

Angiogenesis plays an integral role in follicular and luteal development and is positively regulated by several intra-ovarian factors including vascular endothelial growth factor A (VEGFA) and fibroblast growth factor 2 (FGF2). Various transforming growth factor-β (TGF-β) superfamily members function as intra-ovarian regulators of follicle and luteal function, but their potential roles in modulating ovarian angiogenesis have received little attention. In this study, we used a bovine theca interna culture model (exhibiting characteristics of luteinization) to examine the effects of TGF-β1 and bone morphogenetic protein 6 (BMP6) on angiogenesis and steroidogenesis. VEGFA/FGF2 treatment promoted endothelial cell network formation but had little or no effect on progesterone and androstenedione secretion or expression of key steroidogenesis-related genes. TGF-β1 suppressed basal and VEGFA/FGF2-induced endothelial cell network formation and progesterone secretion, effects that were reversed by an activin receptor-like kinase 5 (ALK5) inhibitor (SB-431542). The ALK5 inhibitor alone raised androstenedione secretion and expression of several transcripts including CYP17A1. BMP6 also suppressed endothelial cell network formation under VEGFA/FGF2-stimulated conditions and inhibited progesterone secretion and expression of several steroidogenesis-related genes under basal and VEGFA/FGF2-stimulated conditions. These effects were reversed by an ALK1/2 inhibitor (K02288). Moreover, the ALK1/2 inhibitor alone augmented endothelial network formation, progesterone secretion, androstenedione secretion and expression of several steroidogenesis-related genes. The results indicate dual suppressive actions of both TGF-β1 and BMP6 on follicular angiogenesis and steroidogenesis. Further experiments are needed to unravel the complex interactions between TGF-β superfamily signalling and other regulatory factors controlling ovarian angiogenesis and steroidogenesis.

Tabanomyces milkoi (Dudka and Koval) emended, genus novum, a fungal pathogen of horseflies

A fungus originally described as a new species of Coelomomyces (C. milkoi) from larval Tabanidae in the Ukraine, USSR, is transferred to a new genus, Tabanomyces, and described in detail. The zygospores germinate to form a linear four-celled conidiophore, each cell producing a spherical conidium ejected as in Conidiobolus, thus confirming that the organism belongs in the Entomophthorales. The resemblance between the conidiophore of Tabanomyces milkoi and the basidium of the rusts supports the old concept that the rust fungi may be related to the Entomophthorales.

Angiogenesis and vascular function in the ovary

Ovarian function is dependent on the establishment and continual remodelling of a complex vascular system. This enables the follicle and/or corpus luteum (CL) to receive the required supply of nutrients, oxygen and hormonal support as well as facilitating the release of steroids. Moreover, the inhibition of angiogenesis results in the attenuation of follicular growth, disruption of ovulation and drastic effects on the development and function of the CL. It appears that the production and action of vascular endothelial growth factor A (VEGFA) is necessary at all these stages of development. However, the expression of fibroblast growth factor 2 (FGF2) in the cow is more dynamic than that of VEGFA with a dramatic upregulation during the follicular–luteal transition. This upregulation is then likely to initiate intense angiogenesis in the presence of high VEGFA levels. Recently, we have developed a novel ovarian physiological angiogenesis culture system in which highly organised and intricate endothelial cell networks are formed. This system will enable us to elucidate the complex inter-play between FGF2 and VEGFA as well as other angiogenic factors in the regulation of luteal angiogenesis. Furthermore, recent evidence indicates that pericytes might play an active role in driving angiogenesis and highlights the importance of pericyte–endothelial interactions in this process. Finally, the targeted promotion of angiogenesis may lead to the development of novel strategies to alleviate luteal inadequacy and infertility.

Telemedicine diagnosis of eye disorders by direct ophthalmoscopy. A pilot study

OBJECTIVE

To report a pilot study of telemedical direct ophthalmoscopy in the diagnosis of acquired immune deficiency syndrome (AIDS)-related retinopathy in a human immunodeficiency virus (HIV)-positive population and in the diagnosis of glaucoma, cataract, and retinopathy in a diabetic population.

DESIGN

Prospective comparative case series.

PARTICIPANTS

Seventeen HIV-positive and 20 diabetic patients.

METHODS

A direct ophthalmoscope custom-fitted with a digital microcamera capable of transmitting images from any of 61 sites within the Georgia Statewide Telemedicine Program was used by a nonophthalmologist to examine 34 eyes of 17 HIV-positive patients and 39 eyes of 20 patients with diabetes. Fundus images were transmitted in real-time to a reviewing ophthalmologist. An in-person, comprehensive examination including indirect ophthalmoscopy, was performed by a second ophthalmologist. Telemedical examination was compared to the in-person comprehensive examination.

RESULTS

For the HIV study, 21 eyes did not show HIV retinopathy (noninfectious retinopathy with cotton-wool spots) by in-person examination. Telemedical examination correctly identified 20 of these eyes as disease-free (specificity = 95%). HIV retinopathy was present in 12 of the 34 eyes by in-person evaluation with telemedical examination correctly diagnosing 10 of these eyes (sensitivity = 83%). One eye with dense cataract and retinal detachment was unable to be evaluated ophthalmoscopically by either in-person or telemedical examination. Telemedical and in-person assessments for HIV retinopathy were identical in 100% of eyes without cataract. Disagreement in diagnosis between telemedical and in-person examination was associated with cataract (P < 0.0007). For the diabetes study, because of an inadequate image, telemedical examination was unable to classify 46% and 36% of eyes for glaucoma and diabetic retinopathy, respectively. Inability to make a telemedical determination for glaucoma (P < 0.011), nonproliferative (P < 0.064) and proliferative (P < 0.064) diabetic retinopathy was associated with cataract. Of the eyes that were able to be assessed by telemedical examination for diabetic retinopathy (n = 25), glaucoma (n = 21), and cataract (n = 39), the accuracy was poor (sensitivity = 29%, 50%, and 41%, respectively). Telemedical examination for diabetic retinopathy and glaucoma was more likely to agree with in-person examination in eyes without cataract as compared to eyes with cataract (not statistically significant).

CONCLUSION

Telemedical direct ophthalmoscopic, real-time fundus imaging may provide a valuable means for providing ophthalmic consultation to the primary care physician in younger patients without lens or media opacity, but is inadequate for eyes with any degree of lens or media opacity.

Predicting and preventing pressure ulcers in adults

Advanced practice nurses and staff nurse skin-care team members provided the necessary expertise and information to integrate AHCPR recommendations in a protocol for patients at risk for skin impairment. Regular practice monitoring and education regarding skin management have proven to be successful strategies. A skin-impairment management protocol is provided.

Modulations in lipid A and phospholipid biosynthesis pathways influence outer membrane protein assembly in Escherichia coli K-12

The assembly defect of a mutant outer membrane protein, OmpF315, can be corrected by suppressor mutations that lower lipopolysaccharide (LPS) levels and indirectly elevate phospholipid levels. One such assembly suppressor mutation, asmB1, is an allele of lpxC (envA) whose product catalyses the first rate-limiting step in the lipid A (LPS) biosynthesis pathway. Besides reducing LPS levels, asmB1 confers sensitivity to MacConkey medium. A mutation, sabA1, that reverses the MacConkey sensitivity phenotype of asmB1 maps within fabZ (whose product is needed for phospholipid synthesis from a precursor) is also required for lipid A synthesis. In addition to reversing MacConkey sensitivity, the sabA1 mutation reverses the OmpF315 assembly suppression phenotype of asmB1. These results show that OmpF315 assembly suppression by asmB1, which is achieved by lowering LPS levels, can be averted by a subsequent aberration in phospholipid synthesis at a point where the biosynthetic pathways for these two lipid molecules split. OmpF315 assembly suppression can also be achieved in an asmB+ background where FabZ expression is increased. The data obtained in this study provide genetic evidence that elevated phospholipid levels and/or phospholipid to LPS ratios are necessary for assembly suppression.

Mobility as a mediator of the effects of child maltreatment on academic performance

This study examined the role of residential and school mobility as a mediator between child maltreatment and academic outcomes. Using a sample of 711 maltreated and nonmaltreated children ranging from 5 to 15 years old matched on gender, grade, school, and socioeconomic status, path analytic techniques were employed to assess direct and indirect effects of maltreatment on recent achievement test scores, current grades, and grade repetitions. The results indicated that mobility did help account for the effects of maltreatment on each of the outcomes. For grades in English/reading, 32.7% of the effect of maltreatment was accounted for by amount of mobility, while for test scores and grade repetitions the numbers were 14.6% and 19.1%, respectively.

Japanese Aedes albopictus among four mosquito species reaching New Zealand in used tires

Since a 1988-89 survey of northern New Zealand revealed no additions to the known mosquito fauna, this country's used tire importations have much increased. Relevant entomological quarantine was thus monitored in a November 1992-January 1993 Auckland project, during which almost 1/3 of 8,549 casings from Japan proved wet on inspection. In this study and at 2 South Island ports afterwards, 5 vessels from Japan and one from Australia were found to have brought in mosquito-infested used tires. Live Aedes albopictus (all larval instars, pupae, and adults) and Aedes japonicus, and dead Tripteroides bambusa were discovered in shipments from Japan (3 interceptions each in the first 2 cases, and one in the 3rd). Live Tripteroides tasmaniensis were recorded from the Australian cargo. One of the Ae. albopictus arrivals was followed by an apprehended introduction at an Auckland importer's premises.

Improving knowledge of emergency physicians about child physical and sexual abuse

The purpose of this project was to study the effect of self-instructional programs regarding physical and sexual abuse on the knowledge and case recognition of physicians. Data from a total of 191 emergency physicians revealed significant improvements from pre- to posttests, as well as increases in case recognition skills. More than 90% of physicians using each kit reported that the information had been valuable and that they would recommend the program to a colleague. The finding that knowledge mastery was high, combined with the recommendations of participating physicians, suggests that the programs tested are promising tools for educating emergency physicians about child physical and sexual abuse.

[Integrated vector control methods and the threat of dengue hemorrhagic fever in the tropical zone of the Pacific Ocean]

Together with a story of the author's earliest visit to Leningrad and first meeting with the late Academician E. N. Pavlovsky , this contribution outlines subsequent developments concerning innovative approaches to the control of Culicidae of medical importance, with particular attention to a major field trial on the atoll of Funafuti , Tuvalu .

Un cas Algérien de parasitisme de Phlebotomus (Paraphlebotomus) sergenti Parrot 1917 par Entomophthorale

The objects of the present note are to describe the case of a sandfly, collected in Algeria, parasitized by organisms that we believe to be assignable to the Entomophthorales; and to suggest that "Coelomomyces" ciferrii Leão and Pedroso is really entomophthoracean too.

Plasmodium durae Herman from the introduced common peafowl in northern Nigeria

Plasmodium (Giovannolaia) durae Herman was originally described from Kenya, the type host being the common turkey, Meleagris gallopavo Linnaeus. There are no field records of this association outside of Africa, where the parasite, herein reported from another introduced and domesticated bird (the common peafowl, Pavo cristatus Linnaeus), was recently listed from 2 native Phasianidae of the genus Francolinus. The justification for the present identification is submitted against background data concerning malaria parasites from turkeys and other Galliformes in Africa and elsewhere, and restraint is urged in describing yet more "new species" of avian Plasmodium belonging to morphologically close taxa within Novyella and Giovannolaia. A near relative of P. durae, Plasmodium dissanaikei de Jong, is transferred from the former subgenus to the latter one.

Tables of critical values for examining compositional non-randomness in proteins and nucleic acids

A binomially distributed statistic pchi2i is defined which in conjunction with a set of critical tables permits, for peptides or proteins of arbitrary lengths, a well-defined answer to the question: Does the proportion of a particular amino acid iota present in that protein deviate significantly from random expectation? An analogous statistic is defined for nucleic acids. This statistic is simply related to the classical chi-squared test. The classical chi2 and the pchi2i are supplementary in that the former permits one to determine that a non-randomness in amino acid composition exists in a protein, while the latter permits one to localize that non-randomness to particular amino acids. The pchi2i statistic takes into account explicity the compositional fluctuations imposed by the finite length of proteins. The tables are more exact than any hitherto existing, and require no intermediate calculations for their use: from the direct experimental measurement of the number of residues of amino acid iota, one immediately reads from the tables whether the number observed is within random expectation or not. These statistics are used to analyze eight proteins of diverse length, function, and origin in an accompanying paper.

Vector ecology and integrated control procedures

The elucidation of population regulatory mechanisms calls for exhaustive biological and ecological studies of whole ecosystems. Until lately, little effort was made to relate insect control activities to such a background, and the use of non-selective pesticides has often resulted in biotic equilibria being disrupted to the ultimate advantage of the organism under attack or of some other undesirable species. However, there is a growing realization in the field of economic entomology at large that biotic control agents usually constitute the major portion of the environmental resistance to increases in pest numbers and that insecticides should be fitted into the ecosystem, and not imposed upon it-in fact, that integrated control procedures are called for.The author considers such integrated procedures from the standpoint of vector control. His paper points out their potentialities in helping to solve resistance problems and in increasing the selectivity of control operations. It further suggests that they offer the means of achieving economical and lasting reductions of vector populations to levels at which human disease transmission is interrupted and pest problems lose much of their importance.