Toward a better understanding of how a gyrified brain develops

The size and shape of the cerebral cortex have changed dramatically across evolution. For some species, the cortex remains smooth (lissencephalic) throughout their lifetime, while for other species, including humans and other primates, the cortex increases substantially in size and becomes folded (gyrencephalic). A folded cortex boasts substantially increased surface area, cortical thickness, and neuronal density, and it is therefore associated with higher-order cognitive abilities. The mechanisms that drive gyrification in some species, while others remain lissencephalic despite many shared neurodevelopmental features, have been a topic of investigation for many decades, giving rise to multiple perspectives of how the gyrified cerebral cortex acquires its unique shape. Recently, a structurally unique germinal layer, known as the outer subventricular zone, and the specialized cell type that populates it, called basal radial glial cells, were identified, and these have been shown to be indispensable for cortical expansion and folding. Transcriptional analyses and gene manipulation models have provided an invaluable insight into many of the key cellular and genetic drivers of gyrification. However, the degree to which certain biomechanical, genetic, and cellular processes drive gyrification remains under investigation. This review considers the key aspects of cerebral expansion and folding that have been identified to date and how theories of gyrification have evolved to incorporate this new knowledge.

Spread of activation and interaction between channels with multi-channel optogenetic stimulation in the mouse cochlea

For individuals with severe to profound hearing loss resulting from irreversibly damaged hair cells, cochlear implants can be used to restore hearing by delivering electrical stimulation directly to the spiral ganglion neurons. However, current spread lowers the spatial resolution of neural activation. Since light can be easily confined, optogenetics is a technique that has the potential to improve the precision of neural activation, whereby visible light is used to stimulate neurons that are modified with light-sensitive opsins. This study compares the spread of neural activity across the inferior colliculus of the auditory midbrain during electrical and optical stimulation in the cochlea of acutely deafened mice with opsin-modified spiral ganglion neurons (H134R variant of the channelrhodopsin-2). Monopolar electrical stimulation was delivered via each of four 0.2 mm wide platinum electrode rings at 0.6 mm centre-to-centre spacing, whereas 453 nm wavelength light was delivered via each of five 0.22 × 0.27 mm micro-light emitting diodes (LEDs) at 0.52 mm centre-to-centre spacing. Channel interactions were also quantified by threshold changes during simultaneous stimulation by pairs of electrodes or micro-LEDs at different distances between the electrodes (0.6, 1.2 and 1.8 mm) or micro-LEDs (0.52, 1.04, 1.56 and 2.08 mm). The spread of activation resulting from single channel optical stimulation was approximately half that of monopolar electrical stimulation as measured at two levels of discrimination above threshold (p<0.001), whereas there was no significant difference between optical stimulation in opsin-modified deafened mice and pure tone acoustic stimulation in normal-hearing mice. During simultaneous micro-LED stimulation, there were minimal channel interactions for all micro-LED spacings tested. For neighbouring micro-LEDs/electrodes, the relative influence on threshold was 13-fold less for optical stimulation compared electrical stimulation (p<0.05). The outcomes of this study show that the higher spatial precision of optogenetic stimulation results in reduced channel interaction compared to electrical stimulation, which could increase the number of independent channels in a cochlear implant. Increased spatial resolution and the ability to activate more than one channel simultaneously could lead to better speech perception in cochlear implant recipients.

Layer-by-Layer Analysis of In Vitro Skin Models

In vitro human skin models are evolving into versatile platforms for the study of skin biology and disorders. These models have many potential applications in the fields of drug testing and safety assessment, as well as cosmetic and new treatment development. The development of in vitro skin models that accurately mimic native human skin can reduce reliance on animal models and also allow for more precise, clinically relevant testing. Recent advances in biofabrication techniques and biomaterials have led to the creation of increasingly complex, multilayered skin models that incorporate important functional components of skin, such as the skin barrier, mechanical properties, pigmentation, vasculature, hair follicles, glands, and subcutaneous layer. This improved ability to recapitulate the functional aspects of native skin enhances the ability to model the behavior and response of native human skin, as the complex interplay of cell-to-cell and cell-to-material interactions are incorporated. In this review, we summarize the recent developments in in vitro skin models, with a focus on their applications, limitations, and future directions.

Could it be monkeypox? Use of an AI-based epidemic early warning system to monitor rash and fever illness

OBJECTIVES

The EPIWATCH artificial intelligence (AI) system scans open-source data using automated technology and can be used to detect early warnings of infectious disease outbreaks. In May 2022, a multicountry outbreak of Mpox in non-endemic countries was confirmed by the World Health Organization. This study aimed to identify signals of fever and rash-like illness using EPIWATCH and, if detected, determine if they represented potential Mpox outbreaks.

STUDY DESIGN

The EPIWATCH AI system was used to detect global signals for syndromes of rash and fever that may have represented a missed diagnosis of Mpox from 1 month prior to the initial case confirmation in the United Kingdom (7 May 2022) to 2 months following.

METHODS

Articles were extracted from EPIWATCH and underwent review. A descriptive epidemiologic analysis was conducted to identify reports pertaining to each rash-like illness, locations of each outbreak and report publication dates for the entries from 2022, with 2021 as a control surveillance period.

RESULTS

Reports of rash-like illnesses in 2022 between 1 April and 11 July (n = 656 reports) were higher than in the same period in 2021 (n = 75 reports). The data showed an increase in reports from July 2021 to July 2022, and the Mann-Kendall trend test showed a significant upward trend (P = 0.015). The most frequently reported illness was hand-foot-and-mouth disease, and the country with the most reports was India.

CONCLUSIONS

Vast open-source data can be parsed using AI in systems such as EPIWATCH to assist in the early detection of disease outbreaks and monitor global trends.

954 Sarcoidosis Mimicking Progression of Melanoma: A Case Report

A 78-year-old lady with a history of malignant melanoma on the dorsal aspect of her left foot, presented with a new fluorodeoxyglucose positron emission tomography (FDG-PET) avid lesion in her left fibular head.

The patient had been diagnosed eight months previously with a 5.1mm Breslow thickness invasive melanoma. Following initial diagnosis, she underwent a wide local excision and sentinel lymph node biopsy (SLN). The melanoma was completely excised and SLN was negative for malignancy.

Postoperatively, she underwent radiological staging with computed tomography scans (CT) of her thorax, abdomen, and pelvis. This showed scattered pulmonary nodules, and multiple indeterminate liver lesions. A PET scan was then performed, which showed an expansile, FDG-avid, lytic lesion in the left fibular head, suspicious for bone metastasis. Following discussion at the multidisciplinary team meeting, the patient underwent an open biopsy of the fibular head. Histology revealed non-necrotising epitheloid granulomata without evidence of malignancy. Ziehl-Neelsen and periodic acid Schiff stains were negative. The findings were suggestive of sarcoidosis.

The patient revealed she had a previous diagnosis of pulmonary sarcoidosis 25 years prior, however, had no known extrapulmonary disease and was not attending a specialist. The pulmonary findings on CT were consistent with sarcoidosis.

Sarcoidosis is a systemic inflammatory disease characterised by the development of non-caseating granulomata which typically affect the lungs and lymph nodes but can affect multiple organ systems. This case highlights the diagnostic uncertainty of an FDG-avid lesion on PET, necessitating diagnostic biopsy. Sarcoidosis is an uncommon but possible differential in this setting.

Traction of 3D and 4D Printing in the Healthcare Industry: From Drug Delivery and Analysis to Regenerative Medicine

Three-dimensional (3D) printing and 3D bioprinting are promising technologies for a broad range of healthcare applications from frontier regenerative medicine and tissue engineering therapies to pharmaceutical advancements yet must overcome the challenges of biocompatibility and resolution. Through comparison of traditional biofabrication methods with 3D (bio)printing, this review highlights the promise of 3D printing for the production of on-demand, personalized, and complex products that enhance the accessibility, effectiveness, and safety of drug therapies and delivery systems. In addition, this review describes the capacity of 3D bioprinting to fabricate patient-specific tissues and living cell systems (e.g., vascular networks, organs, muscles, and skeletal systems) as well as its applications in the delivery of cells and genes, microfluidics, and organ-on-chip constructs. This review summarizes how tailoring selected parameters (i.e., accurately selecting the appropriate printing method, materials, and printing parameters based on the desired application and behavior) can better facilitate the development of optimized 3D-printed products and how dynamic 4D-printed strategies (printing materials designed to change with time or stimulus) may be deployed to overcome many of the inherent limitations of conventional 3D-printed technologies. Comprehensive insights into a critical perspective of the future of 4D bioprinting, crucial requirements for 4D printing including the programmability of a material, multimaterial printing methods, and precise designs for meticulous transformations or even clinical applications are also given.

Replace and repair: Biomimetic bioprinting for effective muscle engineering

The debilitating effects of muscle damage, either through ischemic injury or volumetric muscle loss (VML), can have significant impacts on patients, and yet there are few effective treatments. This challenge arises when function is degraded due to significant amounts of skeletal muscle loss, beyond the regenerative ability of endogenous repair mechanisms. Currently available surgical interventions for VML are quite invasive and cannot typically restore function adequately. In response to this, many new bioengineering studies implicate 3D bioprinting as a viable option. Bioprinting for VML repair includes three distinct phases: printing and seeding, growth and maturation, and implantation and application. Although this 3D bioprinting technology has existed for several decades, the advent of more advanced and novel printing techniques has brought us closer to clinical applications. Recent studies have overcome previous limitations in diffusion distance with novel microchannel construct architectures and improved myotubule alignment with highly biomimetic nanostructures. These structures may also enhance angiogenic and nervous ingrowth post-implantation, though further research to improve these parameters has been limited. Inclusion of neural cells has also shown to improve myoblast maturation and development of neuromuscular junctions, bringing us one step closer to functional, implantable skeletal muscle constructs. Given the current state of skeletal muscle 3D bioprinting, the most pressing future avenues of research include furthering our understanding of the physical and biochemical mechanisms of myotube development and expanding our control over macroscopic and microscopic construct structures. Further to this, current investigation needs to be expanded from immunocompromised rodent and murine myoblast models to more clinically applicable human cell lines as we move closer to viable therapeutic implementation.

Enhancing Peptide Biomaterials for Biofabrication

Biofabrication using well-matched cell/materials systems provides unprecedented opportunities for dealing with human health issues where disease or injury overtake the body’s native regenerative abilities. Such opportunities can be enhanced through the development of biomaterials with cues that appropriately influence embedded cells into forming functional tissues and organs. In this context, biomaterials’ reliance on rigid biofabrication techniques needs to support the incorporation of a hierarchical mimicry of local and bulk biological cues that mimic the key functional components of native extracellular matrix. Advances in synthetic self-assembling peptide biomaterials promise to produce reproducible mimics of tissue-specific structures and may go some way in overcoming batch inconsistency issues of naturally sourced materials. Recent work in this area has demonstrated biofabrication with self-assembling peptide biomaterials with unique biofabrication technologies to support structural fidelity upon 3D patterning. The use of synthetic self-assembling peptide biomaterials is a growing field that has demonstrated applicability in dermal, intestinal, muscle, cancer and stem cell tissue engineering.

The One-Stop Gyrification Station - Challenges and New Technologies

The evolution of the folded cortical surface is an iconic feature of the human brain shared by a subset of mammals and considered pivotal for the emergence of higher-order cognitive functions. While our understanding of the neurodevelopmental processes involved in corticogenesis has greatly advanced over the past 70 years of brain research, the fundamental mechanisms that result in gyrification, along with its originating cytoarchitectural location, remain largely unknown. This review brings together numerous approaches to this basic neurodevelopmental problem, constructing a narrative of how various models, techniques and tools have been applied to the study of gyrification thus far. After a brief discussion of core concepts and challenges within the field, we provide an analysis of the significant discoveries derived from the parallel use of model organisms such as the mouse, ferret, sheep and non-human primates, particularly with regard to how they have shaped our understanding of cortical folding. We then focus on the latest developments in the field and the complementary application of newly emerging technologies, such as cerebral organoids, advanced neuroimaging techniques, and atomic force microscopy. Particular emphasis is placed upon the use of novel computational and physical models in regard to the interplay of biological and physical forces in cortical folding.

Abnormalities of mitochondrial dynamics and bioenergetics in neuronal cells from CDKL5 deficiency disorder

CDKL5 deficiency disorder (CDD) is a rare neurodevelopmental disorder caused by pathogenic variants in the Cyclin-dependent kinase-like 5 (CDKL5) gene, resulting in dysfunctional CDKL5 protein. It predominantly affects females and causes seizures in the first few months of life, ultimately resulting in severe intellectual disability. In the absence of targeted therapies, treatment is currently only symptomatic. CDKL5 is a serine/threonine kinase that is highly expressed in the brain, with a critical role in neuronal development. Evidence of mitochondrial dysfunction in CDD is gathering, but has not been studied extensively. We used human patient-derived induced pluripotent stem cells with a pathogenic truncating mutation (p.Arg59*) and CRISPR/Cas9 gene-corrected isogenic controls, differentiated into neurons, to investigate the impact of CDKL5 mutation on cellular function. Quantitative proteomics indicated mitochondrial defects in CDKL5 p.Arg59* neurons, and mitochondrial bioenergetics analysis confirmed decreased activity of mitochondrial respiratory chain complexes. Additionally, mitochondrial trafficking velocity was significantly impaired, and there was a higher percentage of stationary mitochondria. We propose mitochondrial dysfunction is contributing to CDD pathology, and should be a focus for development of targeted treatments for CDD.

Horses are susceptible to natural, but resistant to experimental, infection with the liver fluke, Fasciola hepatica

Fasciola hepatica is a common parasite of livestock in Ireland, causing significant economic losses and affecting animal welfare. A previous abattoir study of 200 horses led to an estimated 9.5 % prevalence of infection in horses slaughtered in Ireland. However, the epidemiology and pathogenic significance of this infection in this species is not well-described. The objectives of this study were to determine the susceptibility of horses to oral challenge infection with F. hepatica metacercariae, and to document the course of the infection along with serological and biochemical response. We attempted an experimental infection of horses (n = 10; 9 geldings and 1 mare) with F. hepatica. Four were given 1000 metacercariae, four 500 metacercariae and two were sham-infected. Blood and faecal samples were taken at intervals up to 18 weeks post-infection (wpi). ELISA assays were used to assess sero-conversion in the experimental horses and also in a panel of sera from horses of known fluke status. No flukes were recovered from any of the livers, and neither were any lesions that could be attributed to F. hepatica infection observed. Coproantigen ELISA was negative throughout for all horses. Three antibody detection ELISAs, useful in diagnosing fasciolosis in other species, had limitations as diagnostic aids as determined using a panel of sera from horses of known F. hepatica infection status. This study is limited by the relatively small number of animals included, and the relatively short duration of the study period. Failure to establish infection after oral challenge raises fundamental questions on the pathophysiology and epidemiology of equine fasciolosis.

The Relationship between Training and the Experience of Aggression in the Workplace in Residential Care Staff Working in Learning Disability Services

The present study used a questionnaire to examine the following in 50 social care staff: the experience of workplace aggression in staff supporting individuals with a learning disability, the extent to which staff had received training in the prevention and management of aggressive behaviour and the relationship between training and staff confidence in dealing with aggression. The majority of staff were found to have experienced assault in the course of their work. Despite this, less than half had received training in the prevention and management of aggression. Such training seemed to impact differently on males and females, with trained males feeling confident in managing aggression, and untrained males feeling anxious. In contrast, the majority of females reported feelings of anxiety regardless of previous training. Staff reported strategies for dealing with aggression which mainly involved withdrawal of themselves and others rather than physical interventions. However, there was a neglect of longer-term strategies for dealing with aggression. Implications for practice are discussed.

Gender Differences in Assault Levels in a Health Service Unit for People with Learning Disabilities and Severely Challenging Behaviour

The present study examines gender differences and levels of threatened, attempted and actual assaults on staff working in a health service in-patient unit for individuals with learning disabilities over a 35-month period. It was found that the staff experienced high levels of assault overall, but that women experienced significantly higher levels of both threatened and total assaults as compared with men. Implications of the findings are discussed.

3D Bioprinting and Differentiation of Primary Skeletal Muscle Progenitor Cells

Volumetric loss of skeletal muscle can occur through sports injuries, surgical ablation, trauma, motor or industrial accident, and war-related injury. Likewise, massive and ultimately catastrophic muscle cell loss occurs over time with progressive degenerative muscle diseases, such as the muscular dystrophies. Repair of volumetric loss of skeletal muscle requires replacement of large volumes of tissue to restore function. Repair of larger lesions cannot be achieved by injection of stem cells or muscle progenitor cells into the lesion in absence of a supportive scaffold that (1) provides trophic support for the cells and the recipient tissue environment, (2) appropriate differentiational cues, and (3) structural geometry for defining critical organ/tissue components/niches necessary or a functional outcome. 3D bioprinting technologies offer the possibility of printing orientated 3D structures that support skeletal muscle regeneration with provision for appropriately compartmentalized components ranging across regenerative to functional niches. This chapter includes protocols that provide for the generation of robust skeletal muscle cell precursors and methods for their inclusion into methacrylated gelatin (GelMa) constructs using 3D bioprinting.

Adhesion and Self-Assembly of Lubricin (PRG4) Brush Layers on Different Substrate Surfaces

Lubricin (LUB, aka PRG4), a mucin-like glycoprotein, is best known for the significant role it plays in the boundary lubrication, wear protection, and adhesion control systems in human joints. However, LUB exhibits a number of diverse and useful properties, including a remarkable ability to self-assemble into a telechelic brush structure onto virtually any substrate. This self-assembly behavior has spawned the emergence of numerous nontraditional applications of LUB coatings in numerous areas such as microfluidics, electrochemical sensors, contact lenses, antifouling surfaces, and bionic neural interfaces. Although LUB will readily self-assemble on most substrates, it has become apparent that the substrate has a significant influence on the LUB layer's demonstrated lubrication, antiadhesion, electrokinetic, and size-selective transport properties; however, investigations into LUB-substrate interactions and how they influence the self-assembled LUB layer structure remain a neglected aspect of LUB research. This study utilizes AFM force spectroscopy to directly assess the adhesion energy of LUB molecules adsorbed to a wide variety of different substrates which include inorganic, polymeric, and metallic materials. An analysis of the steric repulsive forces measured on approach provides a qualitative assessment of the LUB layer's mechanical modulus, related to the chain packing density, across substrates. These modulus measurements, combined with characteristic features and the dwell time dependence of the LUB adhesion forces provide insight into the organization and uniformity of the LUB brush structure. The results of these measurements indicate that LUB interactions with different substrates are highly variable and substrate-specific, resulting in a surprisingly broad spectrum of adhesion energies and layer properties (i.e., chain density, uniformity, etc.) which are not, themselves, correlated or easily predicted by substrate properties. In addition, this study finds exceptionally poor LUB adhesion to both mica and poly(methyl methacrylate) surfaces that remain widely used substrates for constructing model surfaces in fundamental tribology studies which may have significant implications for the findings of a number of foundational studies into LUB tribology and molecular synergies.

Tailoring the mechanical properties of gelatin methacryloyl hydrogels through manipulation of the photocrosslinking conditions

Photo-crosslinkable hydrogels, in particular gelatin methacryloyl (GelMa), are gaining increasing importance in biofabrication and tissue engineering. While GelMa is often described as mechanically 'tunable', clear relationships linking the photocrosslinking conditions to reaction rates, and the resulting mechanical properties, have not been described. Meanwhile the conditions employed in the literature are disparate, and difficult to compare. In this work, in situ rheological measurements were used to quantify the relative rate of reaction of GelMa hydrogels with respect to light intensity, exposure time and photo-initiator concentration. In addition the UV degradation of the photo-initiator Irgacure 2959 was measured by UV-vis spectroscopy, and used to estimate the rate of free radical production as a function of light exposure. Using these data an expression was derived which predicts the mechanical properties of GelMa hydrogels produced across a wide range of crosslinking conditions. The model was validated through fabrication of a GelMa gradient which matched predicted properties. Human mesenchymal stem cells encapsulated in crosslinked GelMa exhibited high (>90%) viability post encapsulation, however metabolic activity over one week was influenced by the intensity of light used during crosslinking. The expressions described may be used to aid rational choices of GelMa photocrosslinking conditions, especially in cell encapsulation experiments where minimising the cytotoxic elements in the reaction is a priority.

Prevalence of liver fluke infection in Irish horses and assessment of a serological test for diagnosis of equine fasciolosis

BACKGROUND

There is little information on the prevalence of Fasciola hepatica infection in the horse population in Ireland or the potential impact of fluke infection on animal health.

OBJECTIVES

To investigate F. hepatica infection in the Irish horse population and to assess the diagnostic potential of an indirect enzyme-linked immunosorbent assay (ELISA) based on the F. hepatica recombinant cathepsin L1 (CL1) antigen.

STUDY DESIGN

Cross-sectional abattoir survey of horses for liver fluke status.

METHODS

Animals (n = 200) were examined at an abattoir between May 2013 and April 2014. Horses were graded ante mortem for body condition score. Blood and faeces were collected and livers were examined post mortem by gross morphology. A cohort (n = 35) of livers were also examined histologically. Haematology and blood biochemistry, including serum liver enzyme activities, were measured and faeces were sedimented for egg counts. Serum was assayed by indirect ELISA using a recombinant CL1.

RESULTS

The prevalence of liver fluke infection was 9.5%. There was no correlation between liver fluke status and time of year, breed classification, age group, sex, body condition score, ante mortem assessment, strongyle infection status, serum liver enzyme activities or CL1 concentration. A comparison of the CL1 ELISA in horse sera compared with a reference standard diagnosis showed high specificity of 95.6% (95% confidence interval [CI] 91.5-98.0%), but low sensitivity of 42.1% (95% CI 20.2-66.5%).

MAIN LIMITATIONS

This study is limited by its nature as an abattoir study, the relatively small number of animals examined (n = 200), and the absence of a known negative group of horses.

CONCLUSIONS

Blood biomarkers are not good indicators of liver fluke infection and the CL1 ELISA is not a sensitive tool for diagnosis of fluke infection in the horse. The prevalence of F. hepatica in horses indicates that further research is required to assess the potential impact of liver fluke on equine liver health.

Pre-differentiation of human neural stem cells into GABAergic neurons prior to transplant results in greater repopulation of the damaged brain and accelerates functional recovery after transient ischemic stroke

Introduction

Despite attempts to prevent brain injury during the hyperacute phase of stroke, most sufferers end up with significant neuronal loss and functional deficits. The use of cell-based therapies to recover the injured brain offers new hope. In the current study, we employed human neural stem cells (hNSCs) isolated from subventricular zone (SVZ), and directed their differentiation into GABAergic neurons followed by transplantation to ischemic brain.

Methods

Pre-differentiated GABAergic neurons, undifferentiated SVZ-hNSCs or media alone were stereotaxically transplanted into the rat brain (n=7/group) 7 days after endothelin-1 induced stroke. Neurological outcome was assessed by neurological deficit scores and the cylinder test. Transplanted cell survival, cellular phenotype and maturation were assessed using immunohistochemistry and confocal microscopy.

Results

Behavioral assessments revealed accelerated improvements in motor function 7 days post-transplant in rats treated with pre-differentiated GABAergic cells in comparison to media alone and undifferentiated hNSC treated groups. Histopathology 28 days-post transplant indicated that pre-differentiated cells maintained their GABAergic neuronal phenotype, showed evidence of synaptogenesis and up-regulated expression of both GABA and calcium signaling proteins associated with neurotransmission. Rats treated with pre-differentiated cells also showed increased neurogenic activity within the SVZ at 28 days, suggesting an additional trophic role of these GABAergic cells. In contrast, undifferentiated SVZ-hNSCs predominantly differentiated into GFAP-positive astrocytes and appeared to be incorporated into the glial scar.

Conclusion

Our study is the first to show enhanced exogenous repopulation of a neuronal phenotype after stroke using techniques aimed at GABAergic cell induction prior to delivery that resulted in accelerated and improved functional recovery.

The second virial coefficient as a predictor of protein aggregation propensity: A self-interaction chromatography study

The second osmotic virial coefficients (b₂) of four proteins – lysozyme, recombinant human lactoferrin, concanavalin A and catalase were measured by self-interaction chromatography (SIC) in solutions of varying salt type, concentration and pH. Protein aggregate sizes based on the initial hydrodynamic radius of the protein solution species present were measured using dynamic light scattering, and the relationship between b₂ and protein aggregate size was studied. A linear correlation was established between b₂ values and protein aggregate hydrodynamic size for all proteins, and for almost all solution conditions. Aggregate sizes of <∼10 nm, indicative of non-aggregated protein systems, were consistently observed to have b₂ values >0. The observed b₂ trends as a function of solution conditions were very much protein dependent, with notable trends including the existence of attractive interactions (negative b₂ values) at low ionic strengths for catalase and concanavalin A, and the highly positive b₂ values observed for lactoferrin over a wide range of solution conditions, reflecting lactoferrin’s innately high stability. It is concluded that the quantification of protein–protein interactions using SIC based b₂ data is a potentially valuable screening tool for predicting protein aggregation propensity.

Chondrogenesis of infrapatellar fat pad derived adipose stem cells in 3D printed chitosan scaffold

Infrapatellar fat pad adipose stem cells (IPFP-ASCs) have been shown to harbor chondrogenic potential. When combined with 3D polymeric structures, the stem cells provide a source of stem cells to engineer 3D tissues for cartilage repair. In this study, we have shown human IPFP-ASCs seeded onto 3D printed chitosan scaffolds can undergo chondrogenesis using TGFβ3 and BMP6. By week 4, a pearlescent, cartilage-like matrix had formed that penetrated the top layers of the chitosan scaffold forming a 'cap' on the scaffold. Chondrocytic morphology showed typical cells encased in extracellular matrix which stained positively with toluidine blue. Immunohistochemistry demonstrated positive staining for collagen type II and cartilage proteoglycans, as well as collagen type I. Real time PCR analysis showed up-regulation of collagen type II, aggrecan and SOX9 genes when IPFP-ASCs were stimulated by TGFβ3 and BMP6. Thus, IPFP-ASCs can successfully undergo chondrogenesis using TGFβ3 and BMP6 and the cartilage-like tissue that forms on the surface of 3D-printed chitosan scaffold may prove useful as an osteochondral graft.

Changes in drug use and HIV/AIDS risk-taking 1989-90

The Australian National AIDS and Injecting Drug Use Study was designed to monitor the risk behaviour of Australian injecting drug users (IDUs) in a number of major cities, and to estimate the seroprevalence of those interviewed. Differences in risk behaviour found across 2 years in Perth are reported. One hundred and ninety-six Perth IDUs were interviewed in 1989, and 150 in 1990 using the same survey questionnaire, with a small cohort of 38 respondents being followed up across the 2 years.Significant injecting differences between 1989 and 1990 in both the cohort and independent samples were found. In general, these amounted to a greater likelihood that a new needle and syringe would be used on each injecting occasion, and a greater use of bleach in 1990 than in 1989. The most common response of respondents who said they had changed their drug use behaviour in 1990 was to report ceasing to share needles, while the most common response in 1989 was reduced sharing. There was an increased use of condoms for vaginal intercourse with all partners in both studies across the 2 years. Seropositivity for all new cases across the 2 years was 1.75%. It is apparent that there has been a significant shift in risky behaviour in the direction of greater safety across the 2 years. There is also objective corroborative evidence in increased demand for sterile injecting equipment sold through pharmacists, although there is no evidence that drug use increased significantly during the same period. It is concluded that the availability of sterile needles and syringes should be maintained and improved and that emphasis should be placed on encouraging safer sexual behaviour among IDUs.

90-Yttrium-DOTA-octreotate for the treatment of advanced neuroendocrine tumors

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Background: The expression of somatostatin receptors (SSTR) on Neuroendocrine Tumors (NETs) has led not only to tumour visualization utilizing SSTR scintigraphy, but also to the development of receptor-targeted radionuclide therapy. Isotopes such as 111-Indium, 90-Yttrium and 177-Lutetium are linked to somatostatin analogues and then internalized by tumour cells. The recent development of the peptide Octreotate has higher affinity for type 2 SSTR than Octreotide. Aim: to estimate efficacy and tolerability of 90-Yttrium-tyr3-DOTA-octreotate in patients with metastatic progressive NETs. Methods: 89 patients (median age: 51.5 years) with metastatic NETs were studied. All patients had shown signs of progression despite previous treatments. In all patients, the tumours had shown good uptake either in the OctreoScan or in the Ga-68 octreotate PET scan. 64 patients received 3 cycles and 25 patients received 2 cycles of 90-Yttrium-tyr3-DOTA-octreotate. The mean i.v. dose/cycle was 3100 MBq. 29/89 patients included a cycle of intra-arterial therapy with mean dose/cycle 2090 MBq for large volume liver disease. Symptomatic response to treatment was defined as the reduction of >50% to the symptom score and radiological response utilized RECIST criteria. Results: In all patients the post treatment scintigraphy demonstrated good uptake and localization by the tumors. In 59/89 (66%) symptomatic response was achieved. Utilizing RECIST criteria, 50/89 (56%) had disease stabilization (SD) of previously progressive disease and 7 (8%) had partial response (PR). 31/89 (35%) had continued tumor progression. The SD/PR (n=57) group had sustained response for median 17.2 months. Bone marrow toxicity (WHO grade II) was noted in 15/89 (16.8%), persistent in 4 patients with significant bone metastases. Four patients developed mild renal failure (WHO grade II), that was irreversible in one of them. Conclusions: 90Y-DOTA-octreotate is a well-tolerated and safe treatment for patients with progressive neuroendocrine tumors. Early results regarding efficacy are promising.

No significant financial relationships to disclose.

Diagnostic screening of mitochondrial DNA mutations in Australian adults 1990-2001

BACKGROUND

Many diverse pathogenic mitochondrial DNA (mtDNA) mutations have been described since 1988. The Melbourne Neuromuscular Research Institute (MNRI) has undertaken diagnostic detection of selected mtDNA mutations since 1990. MtDNA mutations screened have included point mutations associated with Leber's hereditary optic neuropathy (LHON; G3460A, G11778A and T14484C), mitochondrial encephalopathy lactic acidosis and stroke-like episodes (MELAS; A3243G), myoclonus epilepsy and ragged red fibres (MERRF; A8344G) and Leigh's syndrome/neuropathy ataxia retinitis pigmentosa (LS/NARP; T8993C/G). Samples have also been screened for deletions/ rearrangements associated with Kearns-Sayre syndrome (KSS) and chronic progressive external ophthalmoplegia (CPEO).

AIMS

To present an audit of the MNRI mtDNA diagnostic service between 1990 and 2001, encompassing 1725 referred patients.

METHODS

The detection techniques carried out included polymerase chain reaction amplification of mtDNA combined with restriction fragment length polymorphism analysis for mtDNA point mutation detection, supplemented with selected sequence analysis and Southern blots for the detection of deletions/ rearrangements. Tissues tested included blood, hair and skeletal muscle.

RESULTS

Of the 1184 patients screened for MELAS A3243G, 6.17% were positive for the mutation, whereas for MERRF A8344G, 2.21% carried the mutation and for LS/NARP T8993C/G, 0.32% carried the mutation. The outcomes for the LHON mutations were G11778A, 6.60%, T14484C, 5.76% and G3460A, 0.29%. Of the patients referred for KSS and CPEO, 17.72% had deletions/rearrangements.

CONCLUSIONS

Overall, the detection rate of mtDNA point mutations was low. The protean clinical features of mitochondrial disorders and the frequency of partial phenotypes lead to requests for tests in many patients with a relatively low likelihood of mtDNA mutations. An improved algorithm could involve mutation screening appropriate to the phenotype using sequencing of selected mtDNA regions in patients with a high likelihood of mtDNA disease. Features increasing the likelihood of mtDNA mutations include the following: (i) a typical phenotype, (ii) a maternal inheritance pattern and (iii) histochemical evidence of mitochondrial abnormality in the muscle biopsy. Efficient laboratory diagnosis of mtDNA disease involves good communication between the physician and laboratory scientists, coupled with screening of the appropriate tissue.

Effective detection of corrected dystrophin loci in mdx mouse myogenic precursors

Targeted corrective gene conversion (TCGC) holds much promise as a future therapy for many hereditary diseases in humans. Mutation correction frequencies varying between 0.0001% and 40% have been reported using chimeraplasty, oligoplasty, triplex-forming oligonucleotides, and small corrective PCR amplicons (CPA). However, PCR technologies used to detect correction events risk either falsely indicating or greatly exaggerating the presence of corrected loci. This is a problem that is considerably exacerbated by attempted improvement of the TCGC system using high corrective nucleic acid (CNA) to nuclear ratios. Small fragment homologous replacement (SFHR)-mediated correction of the exon 23 dystrophin (DMD) gene mutation in the mdx mouse model of DMD has been used in this study to evaluate the effect of increasing CPA amounts. In these experiments, we detected extremely high levels of apparently corrected loci and determined that at higher CNA to nuclear ratios the extent of locus correction was highly exaggerated by residual CNA species in the nucleic acids extracted from the treated cells. This study describes a generic locus-specific detection protocol designed to eradicate residual CNA species and avoid the artifactual or exaggerated detection of gene correction.

A novel clinical phenotype of myopathy, sensorimotor neuropathy, infertility, and hypogonadism with multiple mitochondrial DNA deletions

We describe a patient with myopathy, sensorimotor neuropathy, hypogonadism, and infertility with abnormal sperm mobility and morphology. Analysis of the deltoid muscle DNA revealed a G to A change at nt 1102 in the twinkle gene and multiple mitochondrial DNA deletions. Histochemistry revealed "ragged-red" fibers and many cytochrome-c oxidase negative fibers (32%) that lacked the mitochondrial encoded respiratory chain subunits I and II and the nuclear encoded subunit VIc. Respiratory chain enzyme analysis showed severe deficiency of complex I, III, and IV. This patient has no documented family history of progressive external ophthalmoplegia, which suggests either a sporadic or autosomal-recessive syndrome. This case is a novel phenotype for twinkle gene mutations and multiple mitochondrial DNA deletion syndromes, as these syndromes generally follow an autosomal-dominant inheritance pattern.

In vivo and in vitro correction of the mdx dystrophin gene nonsense mutation by short-fragment homologous replacement

Targeted genetic correction of mutations in cells is a potential strategy for treating human conditions that involve nonsense, missense, and transcriptional splice junction mutations. One method of targeted gene repair, single-stranded short-fragment homologous replacement (ssSFHR), has been successful in repairing the common deltaF508 3-bp microdeletion at the cystic fibrosis transmembrane conductance regulator (CFTR) locus in 1% of airway epithelial cells in culture. This study investigates in vitro and in vivo application of a double-stranded method variant of SFHR gene repair to the mdx mouse model of Duchenne muscular dystrophy (DMD). A 603-bp wild-type PCR product was used to repair the exon 23 C-to-T mdx nonsense transition at the Xp21.1 dys locus in cultured myoblasts and in tibialis anterior (TA) from male mdx mice. Multiple transfection and variation of lipofection reagent both improved in vitro SFHR efficiency, with successful conversion of mdx to wild-type nucleotide at the dys locus achieved in 15 to 20% of cultured loci and in 0.0005 to 0.1% of TA. The genetic correction of mdx myoblasts was shown to persist for up to 28 days in culture and for at least 3 weeks in TA. While a high frequency of in vitro gene repair was observed, the lipofection used here appeared to have adverse effects on subsequent cell viability and corrected cells did not express dystrophin transcript. With further improvements to in vitro and in vivo gene repair efficiencies, SFHR may find some application in DMD and other genetic neuromuscular disorders in humans.

An evaluation of a primary care psychological therapies clinic

The present study evaluates a primary care psychological therapies clinic providing input one day per week to a GP practice in a rural area of Scotland. Routine data was collected over a 17 month period and a rating scale was used to evaluate treatment outcomes by both GPs and therapist. In addition GP satisfaction with the service was also evaluated. No significant differences were found between counselling and psychology cases on any of the variables examined. Treatment outcome evaluation showed an overall rate of improvement following treatment, with a mean score of 7 on a 1-10 scale, with 10 representing 'much better'. Significant agreement was found between therapist and GP on rating outcome and no significant differences were found between ratings given by psychologist and counsellor. The GPs involved also expressed high levels of satisfaction with the service.

Evidence on the efficacy of insert earphone and sound field VRA with young infants

Visual reinforcement audiometry (VRA) with insert-earphone stimulus delivery provides a means of obtaining early ear-specific information on the auditory status of infants. The aim of this study was to investigate the efficacy of VRA in young infants, and to compare the use of sound field and insert-earphone stimulus presentation. VRA was performed on 41 normally developing infants aged between 20 and 42 weeks. Infants were tested in the sound field (n=22) and with insert earphones (n=19). Results showed significantly more minimum response levels (MRLs) obtained with sound field testing, and with older children. Nevertheless, in the insert-earphone group, 36% of those aged 32 weeks or more gave two or more MRLs, and 25% of the infants aged 25 weeks or less gave one or more MRLs. This study provides data from developmentally normal infants which confirms the efficacy of insert-earphones as well as sound field VRA with 32-42-week-olds, with reasonable expectation of success. The data in this study also suggest that VRA could be usefully employed for younger infants aged approximately 20-26 weeks where information, although less easily obtained, may be of particular value to early diagnosis and habilitation.

Detection of MELAS A3243G point mutation in muscle, blood and hair follicles

Polymerase chain reaction (PCR) based methods for the diagnosis and screening of the mitochondrial disorders have been well established. A number of tissues are routinely used. In this study, we compared the detection rate for MELAS A3243G point mutation in muscle, blood and hair follicles. Ten subjects were studied; mean age was 47 years, (SD 16, range 23-73). All ten subjects had the MELAS A3243G point mutation detected in muscle and hair follicles, but only five had the abnormality in blood samples. The rate of detection of the point mutation in blood samples was age dependent. MtDNA analysis on hair follicles is as sensitive as muscle in detecting this mutation. Analysis using blood samples is not as sensitive, particularly in older subjects. The absence of the mutation in blood samples suggests that there is a preferential selection process for normal (wild type) mtDNA over time. This may be related to the rate of cell division and energy requirements of each tissue.

Mitochondrial DNA in stroke and migraine with aura

Patients presenting with thrombotic stroke of unexplained etiology and or migraine with aura were screened for mitochondrial (mt) DNA mutations associated with cytopathies given that both migraine and stroke-like episodes are recognised with certain mt DNA mutations. Mutations usually associated with either mitochondrial encephalopathy, lactic acidosis and stroke-like episode, myoclonic epilepsy with ragged red fibres, or those strongly linked to Leber's hereditary optic neuropathy (LHON) were not detected in patients or controls. However, increased levels of two of the secondary LHON mutations were found. The T-->C mutation at nucleotide 4216 was more common than expected in patients aged 35 years or less, as was the 13708 G-->A mutation in young stroke patients. This data lends support to the possibility that an accumulation of minor mt DNA mutations may contribute to the pathoaetiology of stroke and migraine with aura in some young patients.

The polymerase chain reaction in the study of mitochondrial genetics

Since its development in the late 1980's, the polymerase chain reaction (PCR) has revolutionised molecular genetic studies. It has provided direct access to genetic material in quantities sufficient for meaningful analyses to be performed. Adaptations to the basic technique have resulted in a wide range of applications from basic gene amplification to the estimation of DNA species quantities within cells. The study of human mitochondrial genetics is but one of the many disciplines to benefit from the rapid ascension of PCR based technology. In this communication we outline several uses of the PCR technique in the detection, quantification and characterisation of human mitochondrial genetic defects. The data presented in this communication highlight the versatility and applicability of PCR not only to mitochondrial research but to other disciplines of medical research.

Distribution of myocardial macrophages in the normal human heart

Macrophages are important in inflammatory processes in heart disease and in transplantation rejection. A resurgence of interest in the macrophage has emanated from recent evidence implicating it as an effector cell in atherosclerosis and transplantation rejection. The detailed distribution of the macrophage within the normal human heart is unknown. We quantified macrophage numbers in the different chambers of the heart. Large tissue blocks (1.5-2.0 cm3) were removed from specific sites in 5 'normal' control hearts (2 males, 3 females, age range 19-46 y). Paraffin-embedded sections were stained with a CD68 pan macrophage marker. Positive cells were enumerated within 20 random fields. Results were analysed using a generalised linear modelling method using the Poisson distribution. Macrophages were identified within septa, and often close to blood vessels, in the myocardium, and in the majority of areas in all hearts. Macrophage numbers varied significantly between areas (range 0-6 cells/high power field; P < 0.001), and between the 5 hearts analysed (P < 0.001). In general, there were significantly more macrophages in the ventricles (RV P < 0.01, LV P < 0.05), but these differences were affected by heart differences. This study provides a baseline for the range of macrophage numbers within normal hearts, thus enabling comparisons with macrophage numbers within diseased and transplanted hearts.

Varied prevalence of age-associated mitochondrial DNA deletions in different species and tissues: a comparison between human and rat

The prevalence in tissues of mtDNA deletions was compared by PCR between humans and rats of similar "biological ages". Pairs of species-specific primers were used which spanned similar portions of the human and rat mtDNA genomes. There were much fewer PCR products amplified from rat mtDNA than from human mtDNA in each of the three tissues initially analysed: heart, liver and skeletal muscle. By contrast, many more PCR products were amplified from rat kidney than from human kidney. Therefore, while there were far more deletions in heart, liver and skeletal muscle of humans than in corresponding rat tissues, the prevalence of mtDNA deletions was markedly less in human kidney than in rat kidney. The data also indicate that human kidney contains less mtDNA deletions than heart, liver and skeletal muscle in humans; whereas in rat kidney there are more mtDNA deletions than in those three tissues of rat. It is further suggested that, when utilising rodents as experimental models for human ageing, the appropriate tissues should be considered, since not all tissues of rats accumulate mtDNA mutations in the same manner as those of humans.