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Human mesencephalic neurons from the second trimester have been cultured and characterised. Fresh, non-cultured cells were rounded and without processes post-dispersion but in culture differentiated with neurite outgrowth when treated with 2 mMdibutyryl cyclic AMP in the absence of serum. This morphological differentiation could be reversed by the addition of the serine protease, prothrombin. Immunocytochemical staining for dopamine, tyrosine hydroxylase, neuron-specific enolase and glial fibrillary acid protein, demonstrated that dopaminergic, non-dopaminergic and glial elements responded similarly. The conditioned medium contained quantifiable levels of catecholamines as measured by HPLC. These findings are relevant to both developmental neurobiology and clinical neural transplantation, evidencing the considerable plasticity and functional integrity of mesencephalic cells in the second trimester as well as the influence of environmental factors.

Novel polymeric micro-nanostructure meshes as blood vessels substitute have been developed and investigated as a potential solution to the lack of functional synthetic small diameter vascular prosthesis. A commercial elastomeric polyurethane (Tecoflex EG-80A) and a natural biopolymer (gelatin) were successfully co-electrospun from different spinnerets on a rotating mandrel to obtain composite meshes benefiting from the mechanical characteristics of the polyurethane and the natural biopolymer cytocompatibility. Morphological analysis showed a uniform integration of micrometric (Tecoflex) and nanometric (gelatin) fibers. Exposure of the composite meshes to vapors of aqueous glutaraldehyde solution was carried out, to stabilize the gelatin fibers in an aqueous environment. Uniaxial tensile testing in wet conditions demonstrated that the analyzed Tecoflex-Gelatin specimens possessed higher extensibility and lower elastic modulus than conventional synthetic grafts, providing a closer matching to native vessels. Biological evaluation highlighted that, as compared with meshes spun from Tecoflex alone, the electrospun composite constructs enhanced endothelial cells adhesion and proliferation, both in terms of cell number and morphology. Results suggest that composite Tecoflex-Gelatin meshes could be promising alternatives to conventional vascular grafts, deserving of further studies on both their mechanical behaviour and smooth muscle cell compatibility.

Doctors are taking their frustrations about the costs of medical malpractice insurance premiums to the street; striking and even leaving certain states where premiums are higher have been staples of the news in the last year. Politicians are responding by shifting the blame to the “tort” system, which they characterize as dominated by “greedy” trial lawyers (with the implicit accusation that the lawyers are bringing unfounded claims against “good” doctors) and “runaway” juries (with the implicit assertion that juries render plaintiffs’ verdicts in unfounded cases and give away the insurer’s money with abandon through unjustifiably generous damages awards). The “bad actor” in the shared visions of many doctors and politicians is the civil legal system itself—and the “reforms” that are being touted (such as damages caps) are blunt instruments designed, it seems, to disable the ability of the legal system to adjudicate medical malpractice claims. To the extent that the civil legal system is a contributing factor to medical malpractice insurance premiums (an important topic beyond our ken here), the problem cannot be addressed in so sweeping a fashion. There are other key interests involved—principles of law, in the sense described by Ronald Dworkin, upon which the rules of medical malpractice litigation are based. Those principles of law, including the principle of corrective justice, will be sacrificed if such heavy handed measures are adopted. The real problem, however, can be viewed as a much more subtle one, requiring finer tools of analysis to diagnose and repair. The level of subtlety is deep—as deep as the elements of the traditional prima facie case of medical malpractice, and the standard of care in particular—and requires more sophisticated analytic constructs to understand, analyze, and ultimately reform. I hope to develop some of those analytic tools in this article.

Poly(lactic-co-glycolic acid) (PLGA) meshes loaded with retinoic acid (RA) were prepared by applying the electrospinning technique. The purpose of the present work was to combine the biological effects of RA and the advantages of electrospun meshes to enhancing the mass transfer features of controlled release systems and cell interaction with polymeric scaffolds. The processing conditions for the fabrication of three-dimensional meshes were optimized by studying their influence on mesh morphology. Tensile testing showed that RA loading influenced the meshes' mechanical properties by increasing their strength and rigidity. Moreover, the drug release and degradation profiles of the electrospun systems were compared to analogous RA-loaded PLGA films prepared by solvent casting. The results of this study highlight that the electrospun meshes preserved their fibrous structure after 4 months under in vitro physiological conditions and showed a sustained controlled release of the loaded agent in comparison to that observed for cast films. The bioactivity of the loaded RA was investigated on murine preosteoblasts cells by evaluating its influence on cell proliferation and morphology.

It is shown that a non-degenerate curve in ℝ n satisfies a convergent Groshev theorem with a non-monotonic error function. In other words it is shown that if a volume sum converges the set of points lying on the curve which satisfy a Diophantine condition has Lebesgue measure zero.

There is no abstract available for this article.

Foetal tissue from cortex, striatum, cerebellum and mesencephalon of human foetuses of gestational age 18 weeks have been examined for cell viability pre- and postpassage through needles of varying dimensions. Fully dispersed cells have less viability than cell clumps, but needle lumenar sizes employed in this study do not appear to have any significant influence on viability as measured by the vital staining method. There is a tendency of narrower needles to adversely affect viability of both dispersed and clumped cells; the vulnerability of component cells, i.e. neurones or glia has not been determined.

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BACKGROUND: Chemotherapy for brain tumours has been limited because of difficulty in achieving exposure to the tumour without systemic toxicity. Parenteral Irinotecan despite activity against glioma has an uncertain entry into the brain that has questioned its actual efficacy against glioma and a poor profile of enhanced systemic toxicity. In this study we have injected irinotecan sulphonated to PVA beads (1-1000 ) into the brain around tumour following resection of recurrent GBM to assess vehicle and drug safety from disease and procedure related problems. METHODS:10 patients who have failed available therapy for proven recurrent GBM with single focal recurrences as determined by gadolinium enhanced MRI with good performance and ages from 34 -76 were consented for this Phase I study. At operation tumour was removed and the cavity wall injected up to 5mm depth with up to 60 injections of beads suspended in alginate solution delivered using a 24 gauge flexible catheter to a total volume of 3mls and a drug dose of 100mg. Clinical assessments and blood samples were assessed for CTC criteria over 5/7 and imaging and clinical a assessment performed post operation at two and four and eight weekly to 6 months post surgery. RESULTS: To date one (6/15) patient has died at 4/12post treatment of progressive disease and there have been no CTC >2 or procedure related falls in performance despite these patients previous treatment and condition. We have no evidence from this study to suggest any local chemical meningitis or untoward swelling from the injection process. Follow-up is ongoing for survival comparison with other depot therapies. CONCLUSIONS: This novel form of depot therapy offers a stable safe drug loading platform and an accessible generic approach to ensuring local delivery of new agents or those with an uncertain access profile.

The abstract is included in the text.

This paper concerns perturbations of smooth vector fields on $\mathbb{T}^n$ (constant if $n\geq3$) with zeroth-order $C^\infty$ and Gevrey $G^\sigma$, $\sigma\geq1$, pseudodifferential operators. Simultaneous resonance is introduced and simultaneous resonant normal forms are exhibited (via conjugation with an elliptic pseudodifferential operator) under optimal simultaneous Diophantine conditions outside the resonances. In the $C^\infty$ category the results are complete, while in the Gevrey category the effect of the loss of the Gevrey regularity of the conjugating operators due to Diophantine conditions is encountered. The normal forms are used to study global hypoellipticity in $C^\infty$ and Gevrey $G^\sigma$. Finally, the exceptional sets associated with the simultaneous Diophantine conditions are studied. A generalized Hausdorff dimension is used to give precise estimates of the ‘size’ of different exceptional sets, including some inhomogeneous examples.AMS 2000 Mathematics subject classification: Primary 37C15; 11J13. Secondary 58J40; 11J20; 35H05

This paper will review progress on two aspects of the Birmingham BNCT project. Firstly on evaluation of the effects of high and low LET radiations when delivered simultaneously, and secondly on attempts to optimise delivery of the boron carrier compound BPA through pharmacokinetic studies. Simultaneous or non-simultaneous irradiations of V79 cells with alpha-particle and X-ray irradiations were performed. Alpha doses of 2 and 2.5 Gy were chosen and the impact on survival when delivered separately or simultaneously with variable doses of X-rays was evaluated. The pharmacokinetics of the delivery of a new formulation of BPA (BPA-mannitol) are being investigated in brain tumour patients through a study with 2 × 2 design featuring intravenous and intracarotid artery infusion of BPA, with or without a mannitol bolus. On the combined effect of low and high LET radiations, a synergistic effect was observed when alpha and X-ray doses are delivered simultaneously. The effect is only present at the 2.5 Gy alpha dose and is a very substantial effect on both the shape of the survival curve and the level of cell killing. This indicates that the alpha component may have the effect of inhibiting the repair of damage from the low LET radiation dose delivered simultaneously. On the pharmacokinetics of BPA, data on the first three cohorts indicate that bioavailability of BPA in brain ECF is increased substantially through the addition of a mannitol bolus, as well as by the use of intracarotid artery route of infusion. In both cases, for some patients the levels after infusion approach those seen in blood, whereas the ECF levels for intravenous infusion without mannitol are typically less than 10% of the blood values.

BNCT is a biologically targeted radiotherapy where preferential boron uptake interacts with a neutron beam in cancerous cells causing irreparable alpha DNA damage. This requires the delivery of at least 30 parts per million (ppm) of 10B into tumour tissue and 30ppm boron) indicates potential BNCT targeting after surgery. Tumour boron uptake is governed by LAT-1 behaviour rather than BBB penetration and explains previous variable clinical results, whilst supporting the LAT1 determined selection of patients for BNCT

INTRODUCTION: The interaction between an epithermal neutron beam, now deliverable with LINAC technology, and tumour cell accumulated Boron from borono-phenylalanine (BPA), releases an intracellular alpha particle and Li ion causing irrecoverable double strand DNA breaks, insensitive to hypoxia and cell cycle state. Augmented uptake of BPA in GBM cells due to LAT1 upregulation allows targeting of tumour cells, but optimisation of BPA delivery, and neutron exposure time, need clarification before a Phase I trial. METHOD: A pharmacokinetic (Pk)study of newly formulated BPA delivered by iv or close arterial infusion with preinfusion barrier opening, has been carried out in 10 new GBM patients. Plasma, ECF microdialysis, LAT1 activity, Tumour and brain around tumour (BAT) boron10 concentrations of have been used to model the optimum period for neutron beam therapy. RESULTS: 75% of GBM cells are LAT 1 positive, many more than the proliferative index PCNA. Pk studies indicate a three compartment model of BPA cell uptake rate limited by LAT1 exchange kinetics plateauing at four hours. LAT 1 density determines cell Boron dose. LAT1 uptake activity varies between core tumour cells and BAT tumour cells. LAT1 expression maybe particularly elevated in patients with unmethylated MGMT promoter. CONCLUSION: Patients with >50% LAT1 expression are likely to benefit from BNCT with non-LAT1 cells best treated with reduced fraction RT. The BPA uptake pattern favours BAT region tumour cells: those left after surgery regardless of -oxic or cell cycle status. BNCT offers a way of RT dose escalation to discontiguous GBM cells avoiding normal brain, exploits the biology of LAT1 and may offer benefit to patients unresponsive to Temozolomide.

BNCT is a biologically targeted form of enhanced cellular radiotherapy where preferential accumulation of boron in the cancerous as opposed to adjacent normal cells is able to interact with incident neutrons to cause irreversible alpha particle DNA damage. The key to the implementation of this potentially powerful and selective therapy is the delivery of at least 30ppm 10B within the tumour tissue while minimising superfluous 10B in healthy tissue. It is thus an elegant technique for treating infiltrating tumours such as diffuse gliomas. In order to assess its clinical potential we carried out a pharmacokinetic study in glioblastoma patients where we sought to determine the optimal route of delivering a new formulation of the boronated drug (p-boronophenylalanine, BPA), its pharmacokinetic behaviour, toxicity profile, and cellular uptake. Using a number of analytical techniques, including inductively-coupled plasma mass spectrometry, secondary ion mass spectrometry (SIMS) and immunohistochemistry (IHC), boron was measured at various times in blood, urine, cerebrospinal fluid, extracellular fluid (ECF), and tumour-related solid tissue spanning 0.5 h pre- and up to 48 h post-BPA infusion in newly-diagnosed patients (n = 10). Blood was sampled through a central catheter whilst the ECF was sampled by parenchymal microdialysis catheters, placed remotely from the tumour site. Urine was collected over the same time period. Tumour and brain-around tumour (BAT) tissue was sampled stereotactically at 2.5 h and 3.5 h post-infusion. IHC expression levels of the BPA transporter molecule, L-amino acid transporter 1 (LAT-1), were recorded as % LAT-1 positive cells, and cellular boron levels were estimated as spatially resolved pixels in normalised-to-C+ isotopic SIMS images of the biopsies. There were no toxicity-related issues with this new formulation of BPA given at 375 mg/kg as a 2 h intravenous or intracarotid infusion with or without pre-infusion mannitol-induced BBB disruption. The pharmacokinetic profile indicates a high plasma-to-brain concentration gradient from intracarotid infusion and BBB manipulation and reliably places boron in high concentrations in the brain compartment. However, tumour and BAT uptake varied, but a continuing uptake in BAT over time to >30 ppm boron suggests a more favourable capacity to concentrate boron for BNCT after debulking surgery. At the cellular level, the ratio of boron uptake as measured by SIMS in tumour vs BAT was 0.96, 1.85 and 2.40 in the intravenous, intravenous plus mannitol BBB-D, and intracarotid cohorts respectively. Thus improved specific and targeted delivery of boron is possible. These observations conform to a three compartment model where tumoural uptake of boron is governed solely by the abundance and two-way kinetics of tumour LAT-1 activity rather than BBB penetration and may explain some of the variation in clinical results of others.