Breast-to-brain metastasis is exacerbated with chemotherapy through blood-cerebrospinal fluid barrier and induces Alzheimer's-like pathology.

Control of breast-to-brain metastasis remains an urgent unmet clinical need. While chemotherapies are essential in reducing systemic tumor burden, they have been shown to promote non-brain metastatic invasiveness and drug-driven neurocognitive deficits through the formation of neurofibrillary tangles (NFT), independently. Now, in this study, we investigated the effect of chemotherapy on brain metastatic progression and promoting tumor-mediated NFT. Results show chemotherapies increase brain-barrier permeability and facilitate enhanced tumor infiltration, particularly through the blood-cerebrospinal fluid barrier (BCSFB). This is attributed to increased expression of matrix metalloproteinase 9 (MMP9) which, in turn, mediates loss of Claudin-6 within the choroid plexus cells of the BCSFB. Importantly, increased MMP9 activity in the choroid epithelium following chemotherapy results in cleavage and release of Tau from breast cancer cells. This cleaved Tau forms tumor-derived NFT that further destabilize the BCSFB. Our results underline for the first time the importance of the BCSFB as a vulnerable point of entry for brain-seeking tumor cells post-chemotherapy and indicate that tumor cells themselves contribute to Alzheimer's-like tauopathy.

Radio-Pathomic Maps of Cell Density Identify Brain Tumor Invasion beyond Traditional MRI-Defined Margins.

BACKGROUND AND PURPOSE: Currently, contrast-enhancing margins on T1WI are used to guide treatment of gliomas, yet tumor invasion beyond the contrast-enhancing region is a known confounding factor. Therefore, this study used postmortem tissue samples aligned with clinically acquired MRIs to quantify the relationship between intensity values and cellularity as well as to develop a radio-pathomic model to predict cellularity using MR imaging data. MATERIALS AND METHODS: This single-institution study used 93 samples collected at postmortem examination from 44 patients with brain cancer. Tissue samples were processed, stained with H&E, and digitized for nuclei segmentation and cell density calculation. Pre- and postgadolinium contrast T1WI, T2 FLAIR, and ADC images were collected from each patient's final acquisition before death. In-house software was used to align tissue samples to the FLAIR image via manually defined control points. Mixed-effects models were used to assess the relationship between single-image intensity and cellularity for each image. An ensemble learner was trained to predict cellularity using 5 × 5 voxel tiles from each image, with a two-thirds to one-third train-test split for validation. RESULTS: Single-image analyses found subtle associations between image intensity and cellularity, with a less pronounced relationship in patients with glioblastoma. The radio-pathomic model accurately predicted cellularity in the test set (root mean squared error = 1015 cells/mm2) and identified regions of hypercellularity beyond the contrast-enhancing region. CONCLUSIONS: A radio-pathomic model for cellularity trained with tissue samples acquired at postmortem examination is able to identify regions of hypercellular tumor beyond traditional imaging signatures.

Diagnosing variant Creutzfeldt-Jakob disease: a retrospective analysis of the first 150 cases in the UK.

INTRODUCTION: Establishing an early clinical diagnosis in variant Creutzfeldt-Jakob disease (vCJD) can be difficult, resulting in extended periods of uncertainty for many families and sometimes a view that patients have been subjected to unnecessary investigations. This issue is accentuated by the progressive nature of vCJD and by the difficulty in achieving a confident clinical diagnosis before an advanced stage of illness. Although diagnostic delay may be a result of the non-specific early clinical features, a systematic analysis of the process of diagnosis was undertaken, with the aim of trying to achieve earlier diagnosis of vCJD. METHODS: Retrospective case file analysis was undertaken of the first 150 definite and clinically probable cases of vCJD identified by the UK surveillance system. RESULTS: There is a significant interval between illness onset and presentation to a primary care physician, which is influenced by the nature of the initial clinical features. Neurological review is invariably sought following the development of clinical signs and a diagnosis is then established relatively quickly. Despite the progressive clinical course, a confident clinical diagnosis is not usually achieved until a relatively advanced stage of illness (mean time to diagnosis 10.5 months) with a more rapid clinical progression accounting for those cases diagnosed earlier after symptom onset. CONCLUSIONS: Early clinical diagnosis in vCJD is not possible in the great majority of cases because of non-specific initial symptoms. Once neurological signs develop, a diagnosis is usually made promptly but this is often at a relatively advanced stage of illness. The inherent delays in the diagnosis of vCJD have implications for those involved in both public health and therapeutics.

Synthesis and characterization of injectable bioadhesive hydrogels for nucleus pulposus replacement and repair of the damaged intervertebral disc.

Bioadhesive polymers are natural or synthetic materials that can be used for soft tissue repair. The aim of this investigation was to develop an injectable, bioadhesive hydrogel with the potential to serve as a synthetic replacement for the nucleus pulposus of the intervertebral disc or as an annulus closure material. Branched copolymers of poly(N-isopropylacrylamide) (PNIPAAm) and poly(ethylene glycol) (PEG) were blended with poly(ethylene imine) (PEI). This three component injectable system can form a precipitated gel at physiological temperature due to the phase transition of PNIPAAm. The injection of glutaraldehyde into the gel core will adhere the implant to the surrounding tissues. (1)H NMR results indicated the successful physical incorporation of PEI into the PNIPAAm-PEG network by blending. In addition, the covalent crosslinking between the amine functionalities on the PEI and the aldehyde functionalities on the glutaraldehyde was verified using FTIR difference spectroscopy. Mechanical characterization of these blends showed a significant increase (p < 0.05) in compressive modulus following glutaraldehyde injection. The in vitro bioadhesive force studies with porcine skin showed a significant increase (p < 0.05) in the mean maximum force of detachment for PNIPAAm-PEG/PEI gels when glutaraldehyde was injected into the gel core. The results of this study indicate that the reactivity between amines and aldehyde functionalities can be exploited to impart bioadhesive properties to PNIPAAm-PEG/PEI copolymers.

Management training in Vietnam's National Tuberculosis Program: an impact evaluation.

SETTING: National Tuberculosis Program (NTP), Vietnam. OBJECTIVES: To show how the Sustainable Management Development Program (SMDP) of the US Centers for Disease Control and Prevention created capacity within Vietnam's NTP to organize a management training program, and to assess the influence of the NTP's in-country training program on individual and team management practices and the performance of provincial TB control programs. DESIGN: Eight case studies of participating provincial TB organizations, including cross-case and content analysis. RESULTS: Participants and their back-home learning project teams demonstrated a solid understanding of the concepts taught, particularly evidence-based decision making, problem diagnosis and problem solving, and using teamwork to improve results. They gave multiple examples of how they use these concepts in their daily work. Project teams exceeded, attained or very nearly attained their target objectives, including improved DOTS implementation. Process improvements had become a routine part of their practice and were often diffused to other districts. Several teams said they now took more initiative in identifying problems and devising solutions. Others said that increased teamwork was improving the commitment of the NTP staff. CONCLUSION: Management training, including applied projects with coaching, can improve managerial and program performance of NTPs.

Impact of odor from industrial hog operations on daily living activities.

Intensive industrial animal production systems worldwide require confinement of large numbers of animals in small spaces and concentration of enormous quantities of waste. Industrial hog operations, in particular, have raised public concerns about their adverse impact on public health and sustainable development. Using a community-based participatory research approach and qualitative interviews, we explored people's perception of the impact of odor from these industries on daily living activities as they relate to the beneficial use of property and enjoyment of life. Our research indicates that hog odor limits several leisure time activities and social interactions which could have adverse public health consequences. The results of this study can assist the communities and other stakeholders in public policy development that addresses these concerns.

Evaluation of novel injectable hydrogels for nucleus pulposus replacement.

Branched copolymers composed of poly(N-isopropylacrylamide) (PNIPAAm) and poly(ethylene glycol) (PEG) are being investigated as an in situ forming replacement for the nucleus pulposus of the intervertebral disc. A family of copolymers was synthesized by varying the molecular weight of the PEG blocks and molar ratio of NIPAAm monomer units to PEG branches. Gel swelling, dissolution, and compressive mechanical properties were characterized over 90 days and stress relaxation behavior over 30 days immersion in vitro. It was found that the NIPAAm to PEG molar ratio did not affect the equilibrium swelling and compressive mechanical properties. However, gel elasticity exhibited a dependency on both the PEG block molecular weight and content. The equilibrium gel water content increased and compressive modulus decreased with increasing PEG block size. While all of the branched copolymers showed significant increases in stress relaxation time constant compared to the homopolymer (p < 0.05), the high PEG content PNIPAAm-PEG (4600 and 8000 g/mol) exhibited the maximum elasticity. Because of its high water content, requisite stiffness and high elastic response, PNIPAAm-PEG (4600 g/mol) will be further evaluated as a candidate material for nucleus pulposus replacement.

Nondegradable hydrogels for the treatment of focal cartilage defects.

Nondegradable materials have long been suggested for the treatment of articular cartilage defects; however, the mechanics of the implant/tissue system necessary to ensure long-term function are unknown. The objective of this study was to explore the performance of nondegradable hydrogel implants in cartilage defects. Our hypothesis was that the structural integrity of the implant and surrounding tissue would be influenced by the compressive modulus of the material used, and that superior results would be obtained with the implantation of a more compliant material. Poly(vinyl alcohol)-poly(vinyl pyrrolidone) hydrogel implants of two different moduli were implanted into osteochondral defects in a rabbit model. Six-month postoperative histological and mechanical data were used to assess the wear and fixation of the implants. The compliant implants remained well fixed and a thin layer of soft tissue grew over the surface of the implants. However, gross deformation of the compliant implants occurred and debris was evident in surrounding bone. The stiffer implants were dislocated from their implantation site, but with no accompanying evidence of debris or implant deformation. Our hypothesis that superior results would be obtained with implantation of a more compliant material was rejected; a compromise between the wear and fixation properties dependent on modulus was found.

Presentation of a case of variant CJD in general dental practice.

This case report describes the initial presentation of variant CJD to a general dental practitioner. The case highlights the importance of prompt referral of patients presenting with a history of atypical facial symptoms.

Vascularization of PEG-grafted macroporous hydrogel sponges: a three-dimensional in vitro angiogenesis model using human microvascular endothelial cells.

Vascular tissue can penetrate implants that have an interconnected porous structure. The extent of vascularization is heavily dependent on a number of factors, including the nature of the material as well as the size and porosity of the implant's pore morphology. Currently, it is still not clear what mechanisms are controlling this response. In this work, in vitro human microvascular endothelial cell (HMVEC) experiments employed in angiogenesis research have been adapted as a screening technique for biomaterial vascularization. Hydrogels composed of poly(2-hydroxy ethyl methacrylate) (PHEMA) containing poly(ethylene glycol) (PEG) grafts were capable of supporting in vitro tubule formation. The sizes and lengths of tubules were dependent upon the porosity of the polymer network and pore sizes. When compared to the pure PHEMA sponges, PEG-grafted networks possessed a more lattice-type structure, with greater pore interconnection. As a result, these polymers were better suited to supporting tubule formation.

The neuropsychological profile associated with variant Creutzfeldt-Jakob disease.

We report the neuropsychological profile associated with variant Creutzfeldt-Jakob disease (vCJD). A retrospective study was carried out of data from neuropsychological reports prepared on 24 patients with vCJD. While there was some variability in neuropsychological profiles, the overall pattern was one of a combined cortical and subcortical dementia, with impaired performance being particularly prominent on tests of memory, executive function, speed of attention, and visuoperceptual reasoning. Across 16 cases where Wechsler Adult Intelligence Scale-Revised intelligence quotient (IQ) scores were available, this profile was in part reflected by an invariably low performance IQ (<90 in all patients). All patients who received tests of verbal fluency, digit-symbol substitution and faces recognition memory showed deficits on these tests. Basic vocabulary, digit span and verbal reasoning skills were relatively preserved in most patients. In four cases who underwent more detailed cognitive testing, additional observations were made of relatively intact long-term autobiographical memory and faces perception. Cognitive impairment may represent one of the earliest features of vCJD and it is possible that, at least in some cases, neuropsychological deficits precede the onset of psychiatric or neurological symptoms. Our findings may help in the early detection and management of patients with vCJD.

Evaluation of porous networks of poly(2-hydroxyethyl methacrylate) as interfacial drug delivery devices.

Long-term implantable drug delivery devices are desirable to achieve rapid and reliable delivery of bioactive substances to the body. The limitation of most implantable devices is the resulting chronic inflammatory response and fibrous encapsulation of the implant, which prevents effective drug delivery for prolonged periods. One method of overcoming this problem is the addition of an intermediary that could prevent capsule formation. Biocompatible materials with interconnected pore structures greater than 8-10 microm have been shown to support the ingrowth and maintenance of vascularized tissue. In this investigation, we evaluate the efficacy of using porous hydrogel sponges for the tissue interface in an implantable drug delivery device. Porous networks of poly(2-hydroxyethyl methacrylate) (PHEMA) were synthesized using a thermally initiated free-radical solution polymerization. To characterize the microstructure of the PHEMA networks, scanning electron microscopy and mercury porosimetry were used. By altering the solvent fraction in the reaction mixture, PHEMA sponges were synthesized with interconnected pores ranging in size from from 6 to 15 microm with porosities of 55% to 87%. Following the in vitro evaluation, sponges were attached to the distal end of a 20-gauge catheter tubing, and implanted subcutaneously and intraperitoneally. After 5 months implantation, insulin was infused into the devices from external pumps and rapid insulin absorption was observed in conjunction with dramatic lowering of blood glucose levels. From histological evaluation of explanted devices, we observed highly vascularized tissue surrounding the mesenteric implants. These results indicate that it may be possible to use PHEMA sponges for a tissue intermediary for long-term implantable drug delivery devices.

Duplication of the Brassica oleracea APETALA1 floral homeotic gene and the evolution of domesticated cauliflower.

Development of the cauliflower phenotype in Arabidopsis thaliana requires mutations at both the CAULIFLOWER and APETALA1 loci. BoAP1 is the Brassica oleracea orthologue to the Arabidopsis AP1 gene, and is present in two copies in Brassica genomes. The BoAP1-A gene appears to encode a full-length protein, but BoAP1-B alleles in B. oleracea contain insertions that lead to premature translation termination. The BoAP1-B allele found in most B. oleracea subspecies, including B. oleracea ssp. botrytis (domesticated cauliflower) contains a 9 bp insertion in exon 4. This insertion leads to the formation of an in-frame translation termination codon, and these alleles can encode a protein that is truncated at the K domain of this MADS-box transcriptional activator. The allele in B. oleracea ssp. oleracea (wild cabbage) lacks this insertion and instead contains a downstream 4 bp frameshift mutation resulting in the formation of a nonsense mutation. The structure of the BoAP1-B alleles suggests that they are impaired in their ability to perform their floral meristem identity function. These mutations, in conjunction with mutations at the BoCAULIFLOWER (BoCAL) locus, may be associated with the evolution of domesticated cauliflower.

Solute transport analysis in pH-responsive, complexing hydrogels of poly(methacrylic acid-g-ethylene glycol).

We report on the preparation and properties of hydrogels of poly(methacrylic acid-g-ethylene glycol) that exhibit pH-responsive swelling behavior due to the reversible formation/dissociation of interpolymer complexes. Because of their nature, these materials may be useful in drug delivery applications. In this work, we studied the diffusional behavior of three solutes of varying molecular size in the complexing hydrogels as a function of solution pH. The ability of these gels to control the solute diffusion rates was strongly dependent on the molecular size of the solute and the environmental pH. The diffusion coefficients for solutes were calculated as a function of pH and were lower in acidic than neutral or basic media due to the formation of interpolymer complexes in the gels. However, the ratio of the solute radius to the network mesh size also was a significant factor in the overall behavior of these gels. The diffusion coefficient of the smallest solute, proxyphylline, studied only changed by a factor of five between the complexed and uncomplexed state. However, for the largest solute, FITC-dextran, which has a molecular radius ten times greater than proxyphylline, the diffusion coefficients of the drugs in complexed and uncomplexed gels varied by almost two orders of magnitude. These results are explained in terms of mesh size characteristics of the gels.

Poly(ethylene glycol)-containing hydrogels in drug delivery.

The use of hydrogels as carriers for protein delivery has been a subject of significant recent research. In our recent work, we have shown that diffusion controlled delivery of proteins from hydrogels containing poly(ethylene glycol) (PEG) can be possible and controlled by the three-dimensional structure. In addition, a number of these hydrogel carriers are mucoadhesive and can be used for protein delivery. PEG star polymer gels have also been prepared by gamma-irradiation and have been used for protein delivery with and without molecular imprinting. The presence of a large number of functional groups in a small volume makes these polymers important for use in biological and pharmaceutical applications. PEG star polymer hydrogels were synthesized using gamma-irradiation and were characterized using swelling techniques. Equilibrium swelling studies were conducted to investigate the effects of molecular weight, number of star arms, concentration, and radiation dose.

Oral delivery of insulin using pH-responsive complexation gels.

The goal of oral insulin delivery devices is to protect the sensitive drug from proteolytic degradation in the stomach and upper portion of the small intestine. In this work, we investigate the use of pH-responsive, poly(methacrylic-g-ethylene glycol) hydrogels as oral delivery vehicles for insulin. Insulin was loaded into polymeric microspheres and administered orally to healthy and diabetic Wistar rats. In the acidic environment of the stomach, the gels were unswollen due to the formation of intermolecular polymer complexes. The insulin remained in the gel and was protected from proteolytic degradation. In the basic and neutral environments of the intestine, the complexes dissociated which resulted in rapid gel swelling and insulin release. Within 2 h of administration of the insulin-containing polymers, strong dose-dependent hypoglycemic effects were observed in both healthy and diabetic rats. These effects lasted for up to 8 h following administration.

Uptake and release of budesonide from mucoadhesive, pH-sensitive copolymers and their application to nasal delivery.

Microparticles of novel, bioadhesive graft copolymers of polymethacrylic acid and polyethylene glycol (P(MAA-g-EG)) were prepared. The aims of this study were to investigate the uptake and release kinetics of budesonide from P(MAA-g-EG) in vitro as well as the pharmacokinetics following nasal administration of the polymer contained budesonide. The loading of budesonide into the pH-sensitive polymers was examined using various ethanol solutions. Ethanol was required for drug solubilization but hindered hydrogel swelling at pH 7.2. Maximum loading of the drug in the polymer was obtained using 25% ethanol solutions. The release of budesonide from the polymer swollen in 25% ethanol solutions obeyed classical Fickian release behavior after an initial rapid drug burst. For nasal administration of budesonide-containing P(MAA-g-EG) the plasma concentration of budesonide was kept constant following a peak concentration of the drug approximately 45 min after administration.

Comparison of three videokeratoscopes in measurement of toric test surfaces.

PURPOSE: We compared the accuracy of the Computed Anatomy TMS-1 (1.41), the EyeSys Laboratories Corneal Analysis System (2.1), and the Visioptic EH-270 (3.0) videokeratoscopes in measuring toric surfaces. These non-rotationally symmetric aspheric surfaces served as models of corneal astigmatism. METHODS: Precision diamond-turned toric surfaces modeling 0.00 diopter (D) to 7.00 D of astigmatism were fabricated. A three-dimensional contact profiler was developed to calibrate the aspheric surfaces. Videokeratoscopic data taken at "best focus" were compared to the theoretical shape to quantify device measurement errors. RESULTS: The Computed Anatomy system measurement accuracy shows no statistically significant correlation between measurement error and surface toricity (r2 < 0.13). Measurement error increased linearly with surface astigmatism for the EyeSys Laboratories system (0.12 D rms error per D of astigmatism, r2 > 0.96, p < 0.001 and the Visioptic system (0.03 D error per D of astigmatism, r2 = 0.88, p < 0.001). CONCLUSIONS: This study found systematic performance differences among the three machines. Under ideal alignment conditions, the Computed Anatomy TMS-1 is more accurate at detecting astigmatism. The EyeSys Laboratories Corneal Analysis System apparently underestimates the amount of surface astigmatism because of excessive data smoothing. The Visioptic EH-270 errors are primarily in the central zones and may be due to ring localization errors.

Interferometer errors due to the presence of fringes.

Phase-shifting interferometry permits analysis of complex interferograms. However, the measurement accuracy is reduced as the number of fringes is increased. The wave-front from a defocused spherical surface is used to demonstrate this degradation for several different transmission reference objectives.