Towards virtual histology with X-ray grating interferometry

Breast cancer is the most common type of cancer worldwide. Diagnosing breast cancer relies on clinical examination, imaging and biopsy. A core-needle biopsy enables a morphological and biochemical characterization of the cancer and is considered the gold standard for breast cancer diagnosis. A histopathological examination uses high-resolution microscopes with outstanding contrast in the 2D plane, but the spatial resolution in the third, Z-direction, is reduced. In the present paper, we propose two high-resolution table-top systems for phase-contrast X-ray tomography of soft-tissue samples. The first system implements a classical Talbot-Lau interferometer and allows to perform ex-vivo imaging of human breast samples with a voxel size of 5.57 μm. The second system with a comparable voxel size relies on a Sigray MAAST X-ray source with structured anode. For the first time, we demonstrate the applicability of the latter to perform X-ray imaging of human breast specimens with ductal carcinoma in-situ. We assessed image quality of both setups and compared it to histology. We showed that both setups made it possible to target internal features of breast specimens with better resolution and contrast than previously achieved, demonstrating that grating-based phase-contrast X-ray CT could be a complementary tool for clinical histopathology.

Changes in phosphorus mobilization and community assembly of bacterial and fungal communities in rice rhizosphere under phosphate deficiency

Rhizosphere microorganisms are closely associated with phosphorus (P) uptake in plants and are considered potential agents to mitigate P shortage. However, the mechanisms of rhizospheric microbial community assembly under P deficiency have yet to be elucidated. In this study, bacterial and fungal communities in rice rhizosphere and their P mobilization potential under high (+P) and low (−P) concentrations of P were investigated. Bacterial and fungal community structures were significantly different between −P and +P treatments. And both bacterial and fungal P-mobilizing taxa were enriched in-P treatment; however, the proportion of P-mobilizing agents in the fungal community was markedly greater than that in the bacterial community. A culture experiment confirmed that microbial phosphate solubilizing capacity was significantly higher in −P treatment compared with that in +P treatment. −P treatment lowered bacterial diversity in rice rhizosphere but increased fungal diversity. Further analysis demonstrated that the contribution of deterministic processes in governing bacterial community assembly was strengthened under P deficiency but was largely weakened in shaping the fungal community. These results highlighted that enriching P-mobilizing microbes in the rhizosphere is a vital way for rice to cope with P deficiency, and that fungi contribute considerably to P mobilization in rice rhizosphere. Findings from the study provide novel insights into the assembly of the rhizosphere microbiome under P deficiency and this will facilitate the development of rhizosphere microbial regulation strategies to increase nutrient uptake in plants.

Camellia sinensis Chloroplast Fluoride Efflux Gene CsABCB9 Is Involved in the Fluoride Tolerance Mechanism

Soil is a main source of fluoride for plants. The tea plants (Camellia sinensis) accumulate excessive amounts of fluoride in their leaves compared to other plants, but their fluoride tolerance mechanism is poorly understood. A chloroplast fluoride efflux gene (CsABCB9) was newly discovered by using transcriptome analysis, cloned from Camellia sinensis, and its function was demonstrated in the fluoride detoxication mechanism in Escherichia coli/Xenopus laevis oocytes and Arabidopsis thaliana. CsABCB9 is expressed in tea leaves upon F− treatment. The growth of tea, E. coli, and Arabidopsis were inhibited by F− treatment. However, growth of CsABCB9-overexpression in E. coli was shown to increase with lower fluoride content under F− treatment compared to the control. Furthermore, chlorophyll, xanthophyll and soluble sugar contents of CsABCB9-overexpression in Arabidopsis were improved under F− treatment compared to the wild type. CsABCB9 functions in fluoride transport, and the mechanism by which CsABCB9 improves fluoride resistance in tea is mainly chloroplast protection through fluoride efflux.

Effect of carvacrol essential oils on growth performance and intestinal barrier function in broilers with lipopolysaccharide challenge

The purpose of this study was to evaluate the effects of orally administrated carvacrol essential oils (CEOs) on the function of the intestinal barrier in broilers challenged by lipopolysaccharide (LPS). Eighty 28-day-old Ross 308 broilers were assigned to a 2 × 2 factorial arrangement of treatments (20 pens of 1 chick/treatment). Factors were CEOs (with or without orally administered) and LPS (challenged or non-challenged). Individually housed broilers were randomly assigned to four treatments (n = 20 broilers per treatment: 10 males and 10 females): no CEOs and no LPS challenge (NCEOs + NLPS); CEOs and no LPS challenge (CEOs + NLPS); no CEOs and LPS challenge (NCEOs + LPS); CEOs and LPS challenge (CEOs + LPS); all birds were fed the same diet. The broilers were administered 200 μL CEOs daily for 15 days. Orally administered CEOs significantly (P < 0.05) increased the gene expressions of occludin, claudin-1, claudin-5, zonula occludens-1 (ZO-1) and ZO-2 in the small intestinal mucosa, and increased (P < 0.05) the counts of goblet cell in the small intestinal epithelium; LPS-challenge damaged the intestinal barrier, and significantly (P < 0.05) reduced the gene expression of the aforementioned genes and increased the Escherichia coli (P < 0.05) and Salmonella enumeration (P < 0.05) in the intestine of broilers compared with the NCEOs + NLPS group. Injecting LPS reduced (P < 0.05) the gene expression of sIgA compared with the NCEOs + NLPS group. In summary, the CEOs improved the development of the intestinal barrier, to a certain extent, and repaired the intestinal damage caused by LPS.

Effects of oral administration of essential oils on anti-immune stress, antimicrobial properties, and repairing the intestinal damage in broilers challenged by lipopolysaccharide

The aim of the present study was to evaluate the effects of oral administration of essential oils (carvacrol, thyme, and oregano) on anti-immune stress, antimicrobial properties, and repairing the intestinal damage caused by Salmonella enterica lipopolysaccharides (LPS) in broilers. A total of 100 Ross 308 broilers (21-d-old; 1.10 ± 0.11 kg) were randomly allocated to five groups: T1, basal diet + saline; T2, basal diet + LPS; T3, basal diet + 200 μL carvacrol oils + LPS; T4, basal diet + 200 μL thyme oils + LPS; T5, basal diet + 200 μL oregano oils + LPS, with 20 replicates each, and one chicken per replicate per cage. Those challenged by LPS resulted in an immune stress, which manifests as the abnormal growth (P < 0.05) in immune organs, and the content of immunoglobulin G (P < 0.05), tumor necrosis factor-α (P < 0.05), and the rectum temperature (P < 0.05) increased compared with other groups. The oral administration of essential oils controlled the immune stress to a certain extent. The essential oils could reduce harmful bacteria, such as Escherichia coli (P < 0.05) and Salmonella enumeration (P < 0.05), in vivo of broilers. Meanwhile, the essential oils repaired the intestinal damage, which showed a reduction in the villi height (P < 0.05) and goblet cell (P < 0.05) caused by LPS. In conclusion, the essential oils (carvacrol, thyme, and oregano essential oils) controlled the stress reaction and maintained intestinal health to a certain extent.

Effect of carvacrol essential oils on immune response and inflammation-related genes expression in broilers challenged by lipopolysaccharide

This experiment was conducted to study the effects of orally administered carvacrol essential oils on immune response and inflammation-related genes expression in broilers challenged by lipopolysaccharide (LPS). Eighty 28-day-old (1.28 ± 0.15 kg) ROSS 308 broilers were assigned to a 2 × 2 factorial arrangement of treatments (20 pens of 1 chick/trt). Factors were carvacrol essential oil (orally administered or non-orally administered) and LPS (challenged or non-challenged). Individually housed broilers were randomly assigned (n = 20 broilers per treatment: 10 males and 10 females) to four treatments: (1) basic diet (CTR), (2) basic diet + carvacrol (CAR), (3) basic diet + LPS-challenge (LPS), (4) basic diet + carvacrol + LPS-challenge (CAR+LPS). All were fed with the same diet. The experimental period was for 15 d, after which injecting LPS significantly up-regulated the gene expression levels of TNF-α (P < 0.05), IL-1β (P < 0.05), IL-6 (P < 0.05), IL-8 (P < 0.05), TLR2 (P < 0.05), TLR4 (P < 0.05), NF-κB p65 (P < 0.05), AVBD-9 (P < 0.05), and SIgA(P < 0.05) compared with the CTR group; the broilers were challenged by LPS after oral administration of carvacrol, they had significant lower on the gene expression levels of TNF-α (P < 0.05), IL-1β (P < 0.05), IL-6 (P < 0.05), TLR4 (P < 0.05), NF-κB p65 (P < 0.05), and AVBD-9 (P < 0.05) than the LPS group. In conclusion, the broilers orally administrated carvacrol essential oils inhibited the secretion of inflammatory cytokines caused by LPS, affected the pathway of TLRs/NF-κB, and showed an anti-inflammatory function.

[Efficacy and safety of nalbuphine on analgesia of patients in intensive care unit]

OBJECTIVE

To analyze the efficacy and safety of nalbuphine in patients with sedative analgesia in intensive care unit (ICU).

METHODS

A prospective observation was conducted. The adult patients with mild and moderate analgesia in general ICU of the First Affiliated Hospital of Zhengzhou University from January to November in 2017 were enrolled, and they were divided into nalbuphine group and sufentanil group in proper order. The nabobrown group was given 40 mg nabobrown, the sufentanil group was given 0.1 mg sufentanil, both of which were injected with 50 mL normal saline for continuous intravenous infusion in micro-pump. Infusion speed was checked according to pain level. The analgesic target was critical-care pain observation tool (CPOT) score < 2. The change in hemodynamics of patients in both groups were observed, and CPOT score and Richmond agitation-sedation scale (RASS) score were recorded before and l, 3, 5, 12, 24 hours after administration. The analgesic and sedative effects of two drugs were evaluated.

RESULTS

A total of 141 patients were enrolled, including 71 patients in nalbuphine group and 70 in sufentanil group. There was no significant difference in general data including gender, age, body weight, acute physiology and chronic health evaluation II (APACHE II) or pain source, as well as baseline hemodynamics parameter between the two groups. At 1 hour and 3 hours after administration, nalbuphine had no effect on blood pressure, but the heart rate was decreased slightly, while the heart rate and blood pressure of the sufentanil group were decreased obviously. The two drugs could make the heart rate and blood pressure fluctuate obviously with the time of medication, but there was no statistical difference between the two drugs. The two drugs had no significant effect on pulse oxygen saturation (SpO₂) during analgesia. The average dosage of nalbuphine was 0.03 (0.02, 0.05) mg×kg^-1×h^-1 in the nalbuphine group, and the patient was satisfied with the analgesic effect until 3 hours after the use of the drug, and CPOT score was significantly decreased as compared with that before administration [1.0 (1.0, 2.0) vs. 3.0 (2.0, 4.0), P < 0.01], and the sedative effect was increased, RASS score was significantly lower than that before administration [0 (0, 1.0) vs. 1.0 (1.0, 2.0), P < 0.01]. No patients in naporphine group were treated with sufentanil due to unsatisfactory analgesia. The average dosage was 0.11 (0.06, 0.14) μg×kg^-1×h^-1 in the sufentanil group, the patient was satisfied with the analgesic effect until 5 hours after administration, and the CPOT score was significantly lower than that before administration [1.0 (1.0, 2.0) vs. 4.0 (3.0, 6.0), P < 0.01], and the sedative effect was significantly increased, RASS score was significantly lower than that before administration [0 (-1.0, 0) vs. 2.0 (1.0, 2.0), P < 0.01]. The scores of CPOT and RASS in the sufentanil group were significantly higher than those of the naporphine group before use, so the decrease in the CPOT and RASS scores of the two drugs was further analyzed, which indicated the decrease in CPOT score of naporphine group was significantly lower than that in sufentanil group from 3 hours on [1.0 (0, 2.0) vs. 2.0 (1.0, 3.0), P < 0.05], and the decrease in RASS score of naporphine group was significantly lower than that in sufentanil group from 1 hour on [0 (0, 1.0) vs. 1.0 (0, 2.0), P < 0.01]. It suggested that naporphine could achieve sustained and stable analgesic effect and avoid excessive sedation caused by sufentanil.

CONCLUSIONS

Naporphine had a sustained and stable analgesic effect on patients with mild and moderate ICU analgesia. The onset time of naporphine was equivalent to sufentanil, and it had a certain sedative effect and less influence on hemodynamics.

Inhibition of prostate cancer RM1 cell growth in vitro by hydroxyapatite nanoparticle‑delivered short hairpin RNAs against Stat3

The present study investigated the effect of signal transducer and activator of transcription 3 (Stat3) interference on RM1 prostate cancer cell viability in vitro, using plasmid‑based Stat3 specific short hairpin RNA (sh‑Stat3) delivered by hydroxyapatite nanoparticles (HAP). HAP carrying sh‑Stat3 plasmids were transfected into tumor cells. MTT assays were used to measure RM1 cell viability 24 and 48 h following transfection, and the apoptosis rate and cell cycle phase distribution were determined by flow cytometry. Stat3 mRNA expression levels were measured by reverse transcription‑quantitative polymerase chain reaction and Stat3, Cyclin D1, B cell lymphoma 2 apoptosis regulator (Bcl‑2), vascular endothelial growth factor (VEGF), Bcl‑2 associated X apoptosis regulator (Bax) and cleaved‑caspase‑3 protein expression levels were detected using western blot analysis. The results demonstrated that HAP‑delivered sh‑Stat3 significantly decreased RM1 cell viability through the promotion of cell cycle arrest and apoptosis. Stat3 mRNA and protein expression levels were significantly downregulated in RM1 cells. Bcl‑2, VEGF and Cyclin D1 were also significantly downregulated, but cleaved‑caspase‑3 and Bax mRNA and protein expression levels were significantly upregulated. HAP‑delivered sh‑Stat3 decreased RM1 cell viability in vitro, and HAP assisted plasmid‑based delivery of shRNA into tumor cells. The present results suggest that HAP may be a useful method for successful shRNA delivery into tumors.

Effects of essential oil (blended and single essential oils) on anti-biofilm formation of Salmonella and Escherichia coli

Background

Biofilms were the third-dimensional structure in the solid surface of bacteria. Bacterial biofilms were difficult to control by host defenses and antibiotic therapies. Escherichia coli (E. coli) and Salmonella were popular pathogenic bacteria that live in human and animal intestines. Essential oils are aromatic oily liquids from plant materials and well known for their antibacterial activities.

Method

This study was conducted to determine effect of essential oil on anti-biological biofilm formation of E. coli and Salmonella strains in in vitro experiment. Two kinds of bacterial strains were separated from 0.2 g pig feces. Bacterial strains were distributed in 24 plates per treatment and each plates as a replication. The sample was coated with a Bacterial biofilm formation was.

Result

Photographic result, Escherichia coli (E. coli) and Salmonella bacteria colony surface were thick smooth surface in control. However, colony surface in blended and single essential oil treatment has shown crack surface layer compared with colony surfaces in control.

Conclusion

In conclusion, this study could confirm that essential oils have some interesting effect on anti-biofilm formation of E. coli and Salmonella strains from pig feces.

An amphiphilic non-viral gene vector prepared by a combination of enzymatic atom transfer radical polymerization and enzymatic ring-opening polymerization

An amphiphilic non-viral gene vector (PCL-b-PGEA) was prepared by a combination of enzymatic ring-opening polymerization and enzymatic atom transfer radical polymerization for the first time and the kinetic features and gene delivery properties were investigated.

Advantages of a synchrotron bending magnet as the sample illuminator for a wide-field X-ray microscope

In this paper the choice between bending magnets and insertion devices as sample illuminators for a hard X-ray full-field microscope is investigated. An optimized bending-magnet beamline design is presented. Its imaging speed is very competitive with the performance of similar microscopes installed currently at insertion-device beamlines. The fact that imaging X-ray microscopes can accept a large phase space makes them very well suited to the output characteristics of bending magnets which are often a plentiful and paid-for resource. There exist opportunities at all synchrotron light sources to take advantage of this finding to build bending-magnet beamlines that are dedicated to transmission X-ray microscope facilities. It is expected that demand for such facilities will increase as three-dimensional tomography becomes routine and advanced techniques such as mosaic tomography and XANES tomography (taking three-dimensional tomograms at different energies to highlight elemental and chemical differences) become more widespread.

Full-field transmission x-ray microscopy for bio-imaging

A full-field hard-x-ray microscope at SSRL has successfully imaged samples of biological and environmental origin at 40 nm resolution. Phase contrast imaging of trabeculae from a female mouse tibia, loaded in vivo to study the effects of weight-bearing on bone structure, revealed a complex network of osteocytes and canaliculi. Imaging of cordgrass roots exposed to mercury revealed nanoparticles with strong absorption contrast. 3D tomography of yeast cells grown in selenium rich media showed internal structure.

Primary lymphoma of the uterine corpus: an unusual location for a common disease--case report

A case of a primary uterine corpus lymphoma in a 75-year-old woman is described. Immunohistochemical studies showed diffuse large B-cell type one. Primary lymphoma of the uterine corpus is considered to be an unusual location for a common disease.

Extrahepatic portal vein tear with intraperitoneal hemorrhage during TIPS

Temporary occlusion with an angioplasty balloon can stop intraperitoneal bleeding.

Inhibition of the tissue factor-thrombin pathway limits infarct size after myocardial ischemia-reperfusion injury by reducing inflammation

Functional inhibition of tissue factor (TF) has been shown to improve coronary blood flow after myocardial ischemia/reperfusion (I/R) injury. TF initiates the coagulation protease cascade, resulting in the generation of the serine protease thrombin and fibrin deposition. Thrombin can also contribute to an inflammatory response by activating various cell types, including vascular endothelial cells. We used a rabbit coronary ligation model to investigate the role of TF in acute myocardial I/R injury. At-risk areas of myocardium showed increased TF expression in the sarcolemma of cardiomyocytes, which was associated with a low level of extravascular fibrin deposition. Functional inhibition of TF activity with an anti-rabbit TF monoclonal antibody administered either 15 minutes before or 30 minutes after coronary ligation reduced infarct size by 61% (P = 0.004) and 44% (P = 0.014), respectively. Similarly, we found that inhibition of thrombin with hirudin reduced infarct size by 59% (P = 0.014). In contrast, defibrinogenating the rabbits with ancrod had no effect on infarct size, suggesting that fibrin deposition does not significantly contribute to infarct size. Functional inhibition of thrombin reduced chemokine expression and inhibition of either TF or thrombin reduced leukocyte infiltration. We propose that cardiomyocyte TF initiates extravascular thrombin generation, which enhances inflammation and injury during myocardial I/R.

Platelet-activating factor acetylhydrolase prevents myocardial ischemia-reperfusion injury

BACKGROUND

Platelet-activating factor (PAF) is one of the most potent biological mediators of tissue injury. PAF acetylhydrolase (PAF-AH) is a recently isolated naturally occurring enzyme that hydrolyzes PAF and renders it inactive. We hypothesize that inhibition of PAF with PAF-AH will reduce myocardial ischemia-reperfusion (I/R) injury in vivo.

METHODS AND RESULTS

The coronary ligation model was used in New Zealand white rabbits. The large branch of the marginal coronary artery was occluded for 45 minutes, followed by 2 hours of reperfusion. Fifteen minutes before reperfusion, animals were given either 2 mg/kg of vehicle or of PAF-AH. At the completion of 120 minutes of reperfusion, percentage of necrosis, degree of neutrophil infiltration, and measurements of regional contractility were assessed. Data are expressed as the mean+/-SEM and compared by Student's t test or Mann-Whitney ANOVA. Both groups of animals showed an equivalent area at risk; however, 46.7+/-11% was necrotic in the animal treated with vehicle. In contrast, 20.9+/-7.0% was necrotic in the animals treated with PAF-AH (P<0.05). Systolic shortening and wall thickness were significantly greater in those animals treated with PAF-AH at 15, 30, 60, and 120 minutes of reperfusion (P<0.05). Quantification of neutrophil infiltration showed a 62% reduction in the PAF-AH treated animals compared with those treated with vehicle alone.

CONCLUSIONS

PAF-AH is a potent cardioprotective agent in an in vivo model of I/R injury.

Treating myocardial ischemia-reperfusion injury by targeting endothelial cell transcription

Exacerbation of, rather than improvement in, a hypoxic injury after reperfusion of ischemic tissues is recognized as the specific clinicopathologic entity referred to as ischemia/reperfusion (I/R) injury. Arguably, one of the most common forms of I/R injury occurs during cardiac surgery, which has a mandatory period of myocardial ischemia required to allow surgery in a bloodless, motionless field, followed by coronary artery reperfusion after removal of the aortic cross-clamp. In this review, we examine the endothelial cell activation phenotype that initiates and propagates myocardial I/R injury. Emphasis is given to the biology of one transcription factor, NF-kappaB, that has the principal role in the regulation of many endothelial cell genes expressed in activated endothelium. NF-kappaB-dependent transcription of endothelial cell genes that are transcribed in response to I/R injury may be a favorable approach to preventing tissue injury in the setting of I/R. Elucidating safe and effective therapy to inhibit transcription of endothelial cell genes involved in promoting injury after I/R injury may have wide applicability to the patients with heart disease and other forms of I/R injury.

An essential role for NF-kappaB in the cardioadaptive response to ischemia

BACKGROUND

Ischemic preconditioning (IP) is the phenomenon whereby brief episodes of ischemia protect the heart against a subsequent ischemic stress. We hypothesize that activation of the transcription factor NF-kappaB mediates IP.

METHODS

Rabbits were randomly allocated to one of three groups: (1) 45 minutes of myocardial ischemia followed by 2 hours of reperfusion (I/R); (2) three cycles of 5-minute ischemia and 5 minutes of reperfusion followed by I/R (IP + I/R); or (3) IP in the presence of ProDTC, a specific NF-kappaB inhibitor, followed by I/R (IPProDTC + I/R). Infarct size, indices of regional contractility, and NF-kappaB activation were determined.

RESULTS

In preconditioned rabbits (IP + I/R), infarct size was reduced 83% compared with both I/R alone and IPProDTC + I/R groups (p < 0.05). Throughout reperfusion, preconditioned myocardium showed enhanced regional contractile function compared with I/R and IPProDTC + I/R groups (p < 0.05). Gel shift analysis showed NF-kappaB activation with IP that was blocked by ProDTC. I/R and IPProDTC + I/R groups showed NF-kappaB activation with I/R that was absent in preconditioned animals.

CONCLUSIONS

The cytoprotective effects induced by IP require activation of NF-kappaB.

X-ray imaging and microspectroscopy of plants and fungi

X-ray fluorescence microscopy and microspectroscopy with micrometre spatial resolution and unprecedented capabilities for the study of biological and environmental samples are reported. These new capabilities are a result of both the combination of high-brilliance synchrotron radiation and high-performance X-ray microfocusing optics and the intrinsic advantages of X-rays for elemental mapping and chemical-state imaging. In this paper, these capabilities are illustrated by experimental results on hard X-ray phase-contrast imaging, X-ray fluorescence (XRF) imaging and microspectroscopy of mycorrhizal plant roots and fungi in their natural hydrated state. The XRF microprobe is demonstrated by the simultaneous mapping of the elemental distributions of P, S, K, Ca, Mn, Fe, Ni, Cu and Zn with a spatial resolution of approximately 1 x 3 micron and with an elemental sensitivity of approximately 500 p.p.b. Microspectroscopy with the same spatial resolution is demonstrated by recording near-edge X-ray absorption (XANES) spectra of Mn at a concentration of approximately 3 p.p.m.

Solid-phase synthesis of N-substituted amidinophenoxy pyridines as factor XA inhibitors

An arylamidine linker has been employed for the solid-phase synthesis of N-substituted amidinoaryloxypyridine analogs 2 via nucleophilic substitution on a fluoropyridyl template. Two novel N-substituted amidinoaryloxypyridine derivatives 2a and 2b were discovered via this approach.

Measurements of emittance and absolute spectral flux of the PETRA undulator at DESY Hamburg

The first synchrotron radiation beamline using a 4 m-long undulator at the 12 GeV storage ring PETRA delivers hard X-ray photons usable up to 300 keV. The photon intensity is measured on an absolute scale in the energy range between 16 and 60 keV and compared with calculated intensities. The experimental set-up described is also used to measure the horizontal and vertical emittance of the source.

1,2,9,9a-Tetrahydrocyclopropa[c]benz[e]indol-4-one (CBI) analogs of CC-1065 and the duocarmycins: synthesis and evaluation

An extensive study of analogs of the potent antitumor antibiotics CC-1065 and the duocarmycins which incorporate the 1,2,9,9a-tetrahydrocyclopropa[c]benz[e]indol-4-one (CBI) alkylation subunit are detailed. In contrast to early speculation, deep-seated modifications in the CC-1065 and duocarmycin alkylation subunits are well tolerated and the CBI-based analogs proved to be potent cytotoxic agents and efficacious antitumor compounds. Full details of studies defining a direct relationship between functional stability and in vitro cytotoxic potency are described. As such, the readily accessible CBI-based analogs were found to be four times more stable and four times more potent than the corresponding analogs containing the authentic CPI alkylation subunit of CC-1065 and comparable in potency to agents containing the authentic alkylation subunit of duocarmycin SA. Similarly, the CBI-based agents alkylate DNA with an unaltered sequence selectivity at an enhanced rate and with a greater efficiency than the corresponding CPI analog and were comparable to the corresponding analog incorporating the duocarmycin SA alkylation subunit. Systematic and extensive modifications and simplifications in the DNA binding subunits attached to CBI were explored with the comparisons of both enantiomers of CC-1065 and the duocarmycins 2 and 3 with enantiomers of 18-24, 25-29, 57-61, 62-65, 66-68, 72, 73, 78 and 79.

CBI-CDPBO1 and CBI-CDPBI1: CC-1065 analogs containing deep-seated modifications in the DNA binding subunit

The synthesis and preliminary examination of CBI-CDPBO1 (2) and CBI-CDPBI1 (3), CBI analogs of CC-1065 (1) and the duocarmycins incorporating the 3-carbamoyl-1,2-dihydro-3H-pyrrolo[3,2-e]benzoxazole-7-carboxylate (CDPBO) and 3-carbamoyl-1,2-dihydro-3H-pyrrolo[3,2-e]benzimidazole-7-carboxylate (CDPBI) DNA binding subunits, are detailed. The agents contain deep-seated modifications in the DNA binding subunits of the natural products with incorporation of a nitrogen capable of functioning as a hydrogen bond acceptor (CDPBO, CDPBI) or hydrogen bond donor (CDPBI) on their inside concave face which is in intimate contact with the minor groove floor. The CDPBO subunit was prepared through use of a novel and effective MnO2-mediated oxidative coupling of 2-(benzyloxy)ethylamine with 5-hydroxyindole (4) to directly provide 2-[(benzyloxy)methyl]pyrrolo[3,2-e]benzoxazole (6, 48%) in a reaction cascade that initially proceeds with amine regioselective C4 nucleophilic addition to the in situ generated p-quinone monoimine 13. Subsequent conversion of 6 to 8 (debenzylation; MnO2-NaCN, CH3OH) and selective reduction of the fused pyrrole (Et3SiH-CF3CO2H) completed the synthesis of the 1,2-dihydro-3H-pyrrolo[3,2-e]benzoxazole-7-carboxylate ring system. The CDPBI subunit was prepared through selective C4 nitration of 22 followed by reduction of the nitro group and acid-catalyzed closure to the corresponding 2-[(benzyloxy)methyl]pyrrolo[3,2-e]benzimidazole 25. The final conversion of 25 to the 1,2-dihydro-3H-pyrrolo[3,2-e]benzimidazole-7-carboxylate ring system (CDPBI) followed the same protocols introduced for CDPBO. The DNA alkylation efficiencies of 2 and 3 were identical and both were substantially diminished relative to that of CBI-CDPI1 (40). Thus, the introduction of a single nitrogen atom in the DNA binding subunit of 40 has a pronounced and detrimental effect on the relative efficiency (100 x) of DNA alkylation. Consistent with these observations, the in vitro cytotoxic activity of (+)-2 and (+)-3 were comparable (IC50 = 200 pM, L1210) and 40 x less potent than (+)-40 (IC50 = 5 pM, L1210). In contrast to the large impact these small structural changes had on the efficiency of DNA alkylation, the selectivity of DNA alkylation by 2 and 3 was unperturbed and both agents were found to alkylate the same major sites as CBI-CDPI1 (40). The potential origin of these effects is discussed.

CC-1065 CBI analogs: an example of enhancement of DNA alkylation efficiency through introduction of stabilizing electrostatic interactions

The three trimethylammonium salts 3-5 proved to be 100 times more efficient at alkylating DNA than 2 and exhibited DNA alkylation efficiencies identical to that of (+)-CC-1065 (1). In addition, the agents 3 and 4 exhibited DNA alkylation selectivities identical to that of 2. This may be attributed to spatially well-defined stabilizing electrostatic interactions between the positively charged trimethylammonium salt lying on the peripheral face of the agents and the bracketing, negatively charged phosphates located in the DNA backbone that enhance the DNA noncovalent binding affinity without affecting DNA binding or alkylation selectivity. The agent 5 exhibited an altered and more discriminating AT-rich adenine N3 alkylation selectivity than 2-4 that may be attributed to the groove placement of the large trimethylammonium salt.

Soft x-ray instrumentation and its applications at the advanced photon source

Knowledge of the intermediate energy range from 0.5-4 keV, bridging the "soft" and "hard" x-ray regions, is relatively underdeveloped. However, recent developments in the techniques of microscopy and magnetic circular dichroism have emphasized the need to operate in this energy range for microelectronic, biological, and materials science related experiments. The strong dipole-allowed 3d to 4f transitions in rare-earth magnetic materials fall in this region, as do the K-shells of many of the second and third row elements of the periodic table. Two beamlines to be constructed at the Advanced Photon Source (APS) have been designed to cover this energy region. The proposed undulator source, the beamline layout, and the experimental programs for these beamlines are described.

Molecular basis for sequence selective DNA alkylation by (+)- and ent-(-)-CC-1065 and related agents: alkylation site models that accommodate the offset AT-rich adenine N3 alkylation selectivity

A detailed evaluation of the DNA alkylation selectivity of (+)-CC-1065, ent-(-)-CC-1065 and a series of aborted and extended analogs possessing the CPI alkylation subunit is detailed and the refinement of a model that accommodates the offset AT-rich adenine N3 alkylation selectivity of the enantiomeric agents is presented. The natural enantiomers bind in the minor groove in the 3'-->5' direction starting from the adenine N3 alkylation site across a 2 base (N-BOC-CPI; i.e. 5'-AA), 3.5 base (CPI-CDPI1/CPI-PDE-I1; i.e. 5'-AAA), 5 base (CC-1065/CPI-CDPI2; i.e. 5'-AAAAA) or 6.5 base (CPI-CDPI3; i.e. 5'-AAAAAA) AT-rich site. In contrast, the unnatural enantiomers bind in the reverse 5'-->3' direction in the minor groove and the binding site necessarily starts at the first 5' base preceding the adenine N3 alkylation site and extends across the alkylation site to the adjacent 3' bases covering an AT-rich site of 2 bases (N-BOC-CPI; e.g., 5'-AA), 5 bases (CC-1065/CPI-CDPI2; eg. 5'-AAAAA), or 6.5 bases (CPI-CDPI3; e.g. 5'-AAAAAA). Notably, the model accommodates the unusual observation that both enantiomers of N-BOC-CPI alkylate the same sites within duplex DNA (5'-AA > 5'-TA) and the required reversed binding orientation of the enantiomeric agents. The reversed binding orientation is required to permit access to the electrophilic cyclopropane and the resulting offset AT-rich alkylation selectivity is the natural consequence of the diastereomeric relationship of the adducts. Three dimensional models of the natural and unnatural enantiomer alkylations are presented which clearly illustrate the offset binding sites. A fundamentally simple model for the CC-1065 DNA alkylation reaction, that accommodates the behavior of both enantiomers, is provided in which the sequence selectivity is derived from the noncovalent binding selectivity of the agents preferentially in the narrower, sterically more accessible AT-rich minor groove, the inherent steric accessibility to the adenine N3 alkylation site that accompanies deep penetration of the agent into the minor groove within an AT-rich site, and the 2 base-pair (N-BOC-CPI), 3.5 base-pair (CPI-PDE-I1/CPI-CDPI1), 5 base-pair (CC-1065/CPI-CDPI2), or 6.5 base-pair (CPI-CDPI3) site size required to permit agent binding in the minor groove at the alkylation site.(ABSTRACT TRUNCATED AT 400 WORDS)