Visualizing cancer-originating acetate uptake through monocarboxylate transporter 1 in reactive astrocytes in the glioblastoma tumor microenvironment

BACKGROUND

Reactive astrogliosis is a hallmark of various brain pathologies, including neurodegenerative diseases and glioblastomas. However, the specific intermediate metabolites contributing to reactive astrogliosis remain unknown. This study investigated how glioblastomas induce reactive astrogliosis in the neighboring microenvironment and explore 11C-acetate PET as an imaging technique for detecting reactive astrogliosis.

METHODS

Through in vitro, mouse models, and human tissue experiments, we examined the association between elevated 11C-acetate uptake and reactive astrogliosis in gliomas. We explored acetate from glioblastoma cells, which triggers reactive astrogliosis in neighboring astrocytes by upregulating MAO-B and monocarboxylate transporter 1 (MCT1) expression. We evaluated the presence of cancer stem cells in the reactive astrogliosis region of glioblastomas and assessed the correlation between the volume of 11C-acetate uptake beyond MRI and prognosis.

RESULTS

Elevated 11C-acetate uptake is associated with reactive astrogliosis and astrocytic MCT1 in the periphery of glioblastomas in human tissues and mouse models. Glioblastoma cells exhibit increased acetate production as a result of glucose metabolism, with subsequent secretion of acetate. Acetate derived from glioblastoma cells induces reactive astrogliosis in neighboring astrocytes by increasing the expression of MAO-B and MCT1. We found cancer stem cells within the reactive astrogliosis at the tumor periphery. Consequently, a larger volume of 11C-acetate uptake beyond contrast-enhanced MRI was associated with a worse prognosis.

CONCLUSIONS

Our results highlight the role of acetate derived from glioblastoma cells in inducing reactive astrogliosis and underscore the potential value of 11C-acetate PET as an imaging technique for detecting reactive astrogliosis, offering important implications for the diagnosis and treatment of glioblastomas.

Iterative SuFEx approach for sequence-regulated oligosulfates and its extension to periodic copolymers

The synthesis of sequence-regulated oligosulfates has not yet been established due to the difficulties in precise reactivity control. In this work, we report an example of a multi-directional divergent iterative method to furnish oligosulfates based on a chain homologation approach, in which the fluorosulfate unit is regenerated. The oligosulfate sequences are determined by high resolution mass spectrometry of the hydrolyzed fragments, and polysulfate periodic copolymers are synthesized by using oligomeric bisfluorosulfates in a bi-directional fashion. The synthetic utility of this iterative ligation is demonstrated by preparing crosslinked network polymers as synthetic adhesive materials.

11 C-Acetate PET/CT for Reactive Astrogliosis Outperforms 11 C-Methionine PET/CT in Glioma Classification and Survival Prediction

PURPOSE

11 C-acetate (ACE) PET/CT visualizes reactive astrogliosis in tumor microenvironment. This study compared 11 C-ACE and 11 C-methionine (MET) PET/CT for glioma classification and predicting patient survival.

PATIENTS AND METHODS

In this prospective study, a total of 142 patients with cerebral gliomas underwent preoperative MRI, 11 C-MET PET/CT, and 11 C-ACE PET/CT. Tumor-to-contralateral cortex (TNR MET ) and tumor-to-choroid plexus ratios (TNR ACE ) were calculated for 11 C-MET and 11 C-ACE. The Kruskal-Wallis test and Bonferroni post hoc analysis were used to compare the differences in 11 C-TNR MET and 11 C-TNR ACE . The Cox proportional hazards regression analysis and classification and regression tree models were used to assess progression-free survival (PFS) and overall survival (OS).

RESULTS

The median 11 C-TNR MET and 11 C-TNR ACE for oligodendrogliomas (ODs), IDH1 -mutant astrocytomas, IDH1 -wildtype astrocytomas, and glioblastomas were 2.75, 1.40, 2.30, and 3.70, respectively, and 1.40, 1.20, 1.77, and 2.87, respectively. The median 11 C-TNR MET was significantly different among the groups, except between ODs and IDH1 -wildtype astrocytomas, whereas the median 11 C-TNR ACE was significantly different among all groups. The classification and regression tree model identified 4 risk groups ( IDH1 -mutant with 11 C-TNR ACE ≤ 1.4, IDH1 -mutant with 11 C-TNR ACE > 1.4, IDH1 -wildtype with 11 C-TNR ACE ≤ 1.8, and IDH1 -wildtype with 11 C-TNR ACE > 1.8), with median PFS of 52.7, 44.5, 25.9, and 8.9 months, respectively. Using a 11 C-TNR ACE cutoff of 1.4 for IDH1 -mutant gliomas and a 11 C-TNR ACE cutoff of 2.0 for IDH1 -wildtype gliomas, all gliomas were divided into 4 groups with median OS of 52.7, 46.8, 27.6, and 12.0 months, respectively. Significant differences in PFS and OS were observed among the 4 groups after correcting for multiple comparisons.

CONCLUSIONS

11 C-ACE PET/CT is better for glioma classification and survival prediction than 11 C-MET PET/CT, highlighting its potential role in cerebral glioma patients.

Association of Basal Forebrain Volume with Amyloid, Tau, and Cognition in Alzheimer's Disease

Background

Degeneration of cholinergic basal forebrain (BF) neurons characterizes Alzheimer's disease (AD). However, what role the BF plays in the dynamics of AD pathophysiology has not been investigated precisely.

Objective

To investigate the baseline and longitudinal roles of BF along with core neuropathologies in AD.

Methods

In this retrospective cohort study, we enrolled 113 subjects (38 amyloid [Aβ]-negative cognitively unimpaired, 6 Aβ-positive cognitively unimpaired, 39 with prodromal AD, and 30 with AD dementia) who performed brain MRI for BF volume and cortical thickness, 18F-florbetaben PET for Aβ, 18F-flortaucipir PET for tau, and detailed cognitive testing longitudinally. We investigated the baseline and longitudinal association of BF volume with Aβ and tau standardized uptake value ratio and cognition.

Results

Cross-sectionally, lower BF volume was not independently associated with higher cortical Aβ, but it was associated with tau burden. Tau burden in the orbitofrontal, insular, lateral temporal, inferior temporo-occipital, and anterior cingulate cortices were associated with progressive BF atrophy. Lower BF volume was associated with faster Aβ accumulation, mainly in the prefrontal, anterior temporal, cingulate, and medial occipital cortices. BF volume was associated with progressive decline in language and memory functions regardless of baseline Aβ and tau burden.

Conclusions

Tau deposition affected progressive BF atrophy, which in turn accelerated amyloid deposition, leading to a vicious cycle. Also, lower baseline BF volume independently predicted deterioration in cognitive function.

Association of Sleep Disturbances With Brain Amyloid and Tau Burden, Cortical Atrophy, and Cognitive Dysfunction Across the AD Continuum

BACKGROUND AND OBJECTIVES

Patients with Alzheimer disease (AD) frequently suffer from various sleep disturbances. However, how sleep disturbance is associated with AD and its progression remains poorly investigated. We investigated the association of total sleep time with brain amyloid and tau burden, cortical atrophy, cognitive dysfunction, and their longitudinal changes in the AD spectrum.

METHODS

In this retrospective cohort study, we enrolled participants on the AD spectrum who were positive on 18F-florbetaben (FBB) PET. All participants underwent the Pittsburgh Sleep Quality Index, brain MRI, FBB PET, 18F-flortaucipir (FTP) PET, and detailed neuropsychological testing. In addition, a subset of participants completed follow-up assessments. We analyzed the association of total sleep time with the baseline and longitudinal FBB-standardized uptake value ratio (SUVR), FTP-SUVR, cortical thickness, and cognitive domain composite scores.

RESULTS

We examined 138 participants on the AD spectrum (15 with preclinical AD, 62 with prodromal AD, and 61 with AD dementia; mean age 73.4 ± 8.0 years; female 58.7%). Total sleep time was longer in the AD dementia group (7.4 ± 1.6 hours) compared with the preclinical (6.5 ± 1.4 hours; p = 0.026) and prodromal groups (6.6 ± 1.4 hours; p = 0.001), whereas other sleep parameters did not differ between groups. Longer total sleep time was not associated with amyloid accumulation but rather with tau accumulation, especially in the amygdala, hippocampus, basal forebrain, insular, cingulate, occipital, inferior temporal cortices, and precuneus. Longer total sleep time predicted faster tau accumulation in Braak regions V-VI (β = 0.016, p = 0.007) and disease progression to mild cognitive impairment or dementia (hazard ratio = 1.554, p = 0.024). Longer total sleep time was also associated with memory deficit (β = -0.19, p = 0.008).

DISCUSSION

Prolonged total sleep time was associated with tau accumulation in sleep-related cortical and subcortical areas as well as memory dysfunction. It also predicted faster disease progression with tau accumulation. Our study highlights the clinical importance of assessing total sleep time as a marker for disease severity and prognosis in the AD spectrum.

Visualizing reactive astrocyte-neuron interaction in Alzheimer's disease using 11C-acetate and 18F-FDG

Reactive astrogliosis is a hallmark of Alzheimer's disease (AD). However, a clinically validated neuroimaging probe to visualize the reactive astrogliosis is yet to be discovered. Here, we show that PET imaging with 11C-acetate and 18F-fluorodeoxyglucose (18F-FDG) functionally visualizes the reactive astrocyte-mediated neuronal hypometabolism in the brains with neuroinflammation and AD. To investigate the alterations of acetate and glucose metabolism in the diseased brains and their impact on the AD pathology, we adopted multifaceted approaches including microPET imaging, autoradiography, immunohistochemistry, metabolomics, and electrophysiology. Two AD rodent models, APP/PS1 and 5xFAD transgenic mice, one adenovirus-induced rat model of reactive astrogliosis, and post-mortem human brain tissues were used in this study. We further curated a proof-of-concept human study that included 11C-acetate and 18F-FDG PET imaging analyses along with neuropsychological assessments from 11 AD patients and 10 healthy control subjects. We demonstrate that reactive astrocytes excessively absorb acetate through elevated monocarboxylate transporter-1 (MCT1) in rodent models of both reactive astrogliosis and AD. The elevated acetate uptake is associated with reactive astrogliosis and boosts the aberrant astrocytic GABA synthesis when amyloid-β is present. The excessive astrocytic GABA subsequently suppresses neuronal activity, which could lead to glucose uptake through decreased glucose transporter-3 in the diseased brains. We further demonstrate that 11C-acetate uptake was significantly increased in the entorhinal cortex, hippocampus and temporo-parietal neocortex of the AD patients compared to the healthy controls, while 18F-FDG uptake was significantly reduced in the same regions. Additionally, we discover a strong correlation between the patients' cognitive function and the PET signals of both 11C-acetate and 18F-FDG. We demonstrate the potential value of PET imaging with 11C-acetate and 18F-FDG by visualizing reactive astrogliosis and the associated neuronal glucose hypometablosim for AD patients. Our findings further suggest that the acetate-boosted reactive astrocyte-neuron interaction could contribute to the cognitive decline in AD.

Direct 18F-Fluorosulfurylation of Phenols and Amines Using an [18F]FSO2+ Transfer Agent Generated In Situ

We report the direct radiofluorosulfurylation method for the synthesis of ¹⁸F-labeled fluorosulfuryl derivatives from phenols and amines using an [¹⁸F]FSO₂⁺ transfer agent generated in situ. Nucleophilic radiofluorination is achieved even in a hydrous organic medium, obviating the need for azeotropic drying and the use of cryptands. This unprecedented, operationally simple isotopic functionalization facilitates the reliable production of potential radiotracers for positron emission tomography, rendering facile access to SuFEx radiochemistry.

Preclinical Evaluation of a Companion Diagnostic Radiopharmaceutical, [18F]PSMA-1007, in a Subcutaneous Prostate Cancer Xenograft Mouse Model

Several radiolabeled prostate-specific membrane antigen (PSMA)-targeted agents have been developed for detecting prostate cancer, using positron emission tomography imaging and targeted radionuclide therapy. Among them, [¹⁸F]PSMA-1007 has several advantages, including a comparatively long half-life, delayed renal excretion, and compatible structure with α-/β-particle emitter-labeled therapeutics. This study aimed to characterize the preclinical pharmacokinetics and internal radiation dosimetry of [¹⁸F]PSMA-1007, as well as its repeatability and specificity for target binding using prostate tumor-bearing mice. In PSMA-positive tumor-bearing mice, the kidney showed the greatest accumulation of [¹⁸F]PSMA-1007. The distribution in the tumor attained its peak concentration of 2.8%ID/g at 112 min after intravenous injection. The absorbed doses in the tumor and salivary glands were 0.079 ± 0.010 Gy/MBq and 0.036 ± 0.006 Gy/MBq, respectively. The variance of the net influx (K_i) of [¹⁸F]PSMA-1007 to the tumor was minimal between scans performed in the same animals (within-subject coefficient of variation = 7.57%). [¹⁸F]PSMA-1007 uptake in the tumor was specifically decreased by 32% in K_i after treatment with a PSMA inhibitor 2-(phosphonomethyl)-pentanedioic acid (2-PMPA). In the present study, we investigated the in vivo preclinical characteristics of [¹⁸F]PSMA-1007. Our data from [¹⁸F]PSMA-1007 PET/computed tomography (CT) studies in a subcutaneous prostate cancer xenograft mouse model supports clinical therapeutic strategies that use paired therapeutic radiopharmaceuticals (such as [¹⁷⁷Lu]Lu-PSMA-617), especially strategies with a quantitative radiation dose estimate for target lesions while minimizing radiation-induced toxicity to off-target tissues.

Rapid access to polycyclic N-heteroarenes from unactivated, simple azines via a base-promoted Minisci-type annulation

Conventional synthetic methods to yield polycyclic heteroarenes have largely relied on metal-mediated arylation reactions requiring pre-functionalised substrates. However, the functionalisation of unactivated azines has been restricted because of their intrinsic low reactivity. Herein, we report a transition-metal-free, radical relay π-extension approach to produce N-doped polycyclic aromatic compounds directly from simple azines and cyclic iodonium salts. Mechanistic and electron paramagnetic resonance studies provide evidence for the in situ generation of organic electron donors, while chemical trapping and electrochemical experiments implicate an iodanyl radical intermediate serving as a formal biaryl radical equivalent. This intermediate, formed by one-electron reduction of the cyclic iodonium salt, acts as the key intermediate driving the Minisci-type arylation reaction. The synthetic utility of this radical-based annulative π-extension method is highlighted by the preparation of an N-doped heptacyclic nanographene fragment through fourfold C–H arylation.

The functionalisation of unactivated azines has been restricted because of their intrinsic low reactivity. Here the authors show a transition-metal-free, radical relay π-extension approach to produce N-doped polycyclic aromatic compounds directly from simple azines and cyclic iodonium salts.

Late-Stage 18F/19F Isotopic Exchange for the Synthesis of 18F-Labeled Sulfamoyl Fluorides

Synthesis of sulfamoyl [¹⁸F]fluorides has been a challenging topic owing to the inefficient nucleophilic radiofluorination of sulfamoyl derivatives. Herein, we report an ¹⁸F/¹⁹F isotopic exchange approach to synthesize various sulfamoyl [¹⁸F]fluorides, otherwise inaccessible via direct synthesis from amines, with high radiochemical yields up to 97% (30 examples). This late-stage labeling protocol offers an efficient route to yield functionalized molecules by diversifying the chemical library possessing sulfamoyl functionalities through nucleophilic ¹⁸F incorporation within nitrogen-containing sulfur(VI) frameworks.

Synthesis of 18F-Labeled Aryl Fluorosulfates via Nucleophilic Radiofluorination

Sulfuryl fluoride gas is a key reagent for SO₂F transfer. However, conventional SO₂F transfer reactions have limited ¹⁸F-radiochemistry translation, due to the inaccessibility of gaseous [¹⁸F]SO₂F₂. Herein, we report the first SO₂F₂-free synthesis of aryl [¹⁸F]fluorosulfates from both phenolic and isolated aryl imidazylate precursors with cyclotron-produced ¹⁸F^-. The radiochemical yields ranged from moderate to good with excellent functional group tolerance. The reliability of our approach was validated by the automated radiosynthesis of 4-acetamidophenyl [¹⁸F]fluorosulfate.

Re-evaluation of the diagnostic performance of 11C-methionine PET/CT according to the 2016 WHO classification of cerebral gliomas

PURPOSE

We evaluated the usefulness of ¹¹C-methionine (MET) positron emission tomography/computed tomography (PET/CT) for grading cerebral gliomas according to the 2016 WHO classification with special emphasis on the presence of the isocitrate dehydrogenase 1 (IDH1) gene mutation and 1p/19q codeletion.

METHODS

In total, 144 patients underwent MET PET/CT before surgery. The ratios of the maximum standardized uptake value (SUV) of the gliomas to the mean SUV of the contralateral cortex on MET PET/CT (MET TNR) were calculated.

RESULTS

The median MET TNRs in IDH1-mutant and IDH1-wildtype tumours were 1.95 and 3.35, respectively. From among 74 IDH1-mutant tumours, the oligodendrogliomas showed a higher median MET TNR than the astrocytic tumours (2.90 vs. 1.40, P < 0.001). In grade II, III and IV IDH1-mutant astrocytic tumours, the median MET TNRs were 1.20, 2.05 and 2.20, respectively (grade II vs. grade III, P < 0.0001; grade II vs. grade IV, P = 0.023). In oligodendrogliomas, the MET TNR was lower fin grade II tumours than in grade III tumours (2.30 vs. 3.30 P = 0.008). In differentiating low-grade (grade II) from high-grade (grade III and IV) gliomas, receiver operating characteristic analysis showed a higher area under the curve for wildtype tumours (0.976) than for all tumours (0.852; P < 0.001) and IDH1-mutant tumours (0.817; P = 0.004).

CONCLUSION

IDH1-mutant tumours showed lower MET uptake than IDH1-wildtype tumours. Regardless of IDH1 mutation status, oligodendrogliomas with 1p/19q codeletion showed MET uptake as high as that in high-grade IDH1-wildtype tumours. Therefore, MET uptake for glioma grading was more consistent for IDH1-wildtype tumours than for IDH1-mutant tumours.

Catalyst-Free Aromatic Radiofluorination via Oxidized Iodoarene Precursors

Oxidized iodoarenes (OIAs), prepared via mCPBA-mediated oxidation, have been demonstrated as versatile precursors for the synthesis of [¹⁸F]fluoroarenes in the absence of catalysts. OIAs have been identified as intermediates in single-pot syntheses of iodonium salts and ylides but have never been recognized as radiofluorination precursors. Here, the isolated OIAs were used without any catalysts to produce functionalized [¹⁸F]fluoroarenes, regardless of the electronic nature of the arenes. This method was also applied to the production of radiolabeling synthons for use as aromatic ¹⁸F-labeled building blocks.

Automated cGMP-compliant radiosynthesis of [18 F]-(E)-PSS232 for brain PET imaging of metabotropic glutamate receptor subtype 5

(E)-3-(Pyridin-2-yl ethynyl)cyclohex-2-enone O-(3-(2-[¹⁸ F]-fluoroethoxy)propyl) oxime ([¹⁸ F]-(E)-PSS232, [¹⁸ F]2a) is a recently developed radiotracer that can be used to visualize metabotropic glutamate receptor subtype 5 (mGlu₅ ) in vivo. The mGlu₅ has become an attractive therapeutic and diagnostic target owing to its role in many neuropsychiatric disorders. Several carbon-11-labeled and fluorine-18-labeled radiotracers have been developed to measure mGlu₅ receptor occupancy in the human brain. The radiotracer [¹⁸ F]2a, which is used as an analogue for [¹¹ C]ABP688 ([¹¹ C]1) and has a longer physical half-life, is a selective radiotracer that exhibits high binding affinity for mGlu₅ . Herein, we report the fully automated radiosynthesis of [¹⁸ F]2a using a commercial GE TRACERlab™ FX-_FN synthesizer for routine production and distribution to nearby satellite clinics. Nucleophilic substitution of the corresponding mesylate precursor with cyclotron-produced [¹⁸ F]fluoride ion at 100°C in dimethyl sulfoxide (DMSO), followed by high-performance liquid chromatography (HPLC) purification and formulation, readily provided [¹⁸ F]2a with a radiochemical yield of 40 ± 2% (decay corrected, n = 5) at the end of synthesis. Radiochemical purity for the [¹⁸ F]-(E)-conformer was greater than 95%. Molar activity was determined to be 63.6 ± 9.6 GBq/μmol (n = 5), and the overall synthesis time was 70 minutes.

Crystal Structures of Diaryliodonium Fluorides and Their Implications for Fluorination Mechanisms

The radiofluorination of diaryliodonium salts is of value for producing radiotracers for positron emission tomography. We report crystal structures for two diaryliodonium fluorides. Whereas diphenyliodonium fluoride (1 a) exists as a tetramer bridged by four fluoride ions, 2-methylphenyl(phenyl)iodonium fluoride (2 a) forms a fluoride-bridged dimer that is further halogen bonded to two other monomers. We discuss the topological relationships between the two and their implications for fluorination in solution. Both radiofluorination and NMR spectroscopy show that thermolysis of 2 a gives 2-fluorotoluene and fluorobenzene in a 2 to 1 ratio that is in good agreement with the ratio observed from the radiofluorination of 2-methylphenyl(phenyl)iodonium chloride (2 b). The constancy of the product ratio affirms that the fluorinations occur via the same two rapidly interconverting transition states whose energy difference dictates chemoselectivity. From quantum chemical studies with density functional theory we attribute the "ortho-effect" to the favorable electrostatic interaction between the incoming fluoride and the o-methyl in the transition state. By utilizing the crystal structures of 1 a and 2 a, the mechanisms of fluoroarene formation from diaryliodonium fluorides in their monomeric, homodimeric, heterodimeric, and tetrameric states were also investigated. We propose that oligomerization energy dictates whether the fluorination occurs through a monomeric or an oligomeric pathway.

The Effect of 3-Isocyanato-1-Propene on Adhesive Properties of UV-Curing Urethane/Siloxane Acrylate Resin

We synthesized the urethane/siloxane acrylate oligomer from isophorone diisocyanate (IPDI), hydroxyl alkyl terminated polydimethylsiloxane and 2-hydroxyethyl acrylate (2-HEA). UV-curable resins were formulated from the synthesized oligomer, ethylene glycol phenyl ether acrylate (PHEA), 1,6-hexanediol diacrylate (HDDA), trimethylolpropane triacrylate (TMPTA) as a reactive diluent, 3-isocyanato-1-propene as an adhesion promoter and photoinitiators. The PET film was treated with plasma in order to introduce the functional group on the PET surface and the functional group was observed through X-ray photoelectron spectroscopy (XPS) and the Fourier transform infrared (FT-IR). The adhesion strength between the PET film and the UV-cured resin were increased by using the adhesion promoter. Also, the thermal stability, the modulus and surface hardness were increased, as the adhesion promoter was added.

Single-step syntheses of no-carrier-added functionalized [18F]fluoroarenes as labeling synthons from diaryliodonium salts

Radiotracers labelled with short-lived fluorine-18 (t(1/2) = 109.7 min) are keenly sought for biomedical imaging with positron emission tomography (PET). The radiotracers are mostly required at high specific radioactivities, necessitating their radiosyntheses from cyclotron-produced no-carrier-added [(18)F]fluoride ion. PET radiotracers encompass wide structural diversity and molecular weight. Hence, diverse (18)F-labeling methodology is needed to accomplish the required radiosyntheses in a simple and rapid manner. A useful strategy is to introduce nucleophilic [(18)F]fluoride ion first into a labeling synthon that may then be applied to label the target radiotracer. Here, we show that various functionalized [(18)F]fluoroarenes may be rapidly synthesized as labeling synthons through single-step reactions of appropriate diaryliodonium salts with [(18)F]fluoride ion. Decay-corrected radiochemical yields (RCYs) varied with position of functional group, choice of electron-rich aryl ring in the diaryliodonium salt, and choice of anion. Under best conditions, (18)F-labeled fluorobenzaldehydes, fluorobenzyl halides, fluorobenzoic acid esters and fluorophenyl ketones were obtained selectively in 40-73%, 20-55%, 46-89% and 81-98% RCYs, respectively. This versatile straightforward methodology will enhance the scope for producing structurally complex, yet useful, PET radiotracers.

Radiofluorination of diaryliodonium tosylates under aqueous-organic and cryptand-free conditions

Positron emission tomography (PET) has growing importance as a molecular imaging technique in clinical research and drug development. Methods for producing PET radiotracers utilizing cyclotron-produced [(18)F]fluoride ion (t1/2 = 109.7 min) without the need for complete removal of irradiated target [(18)O]water and addition of cryptand are keenly sought for practical convenience and efficiency. Several structurally diverse diaryliodonium tosylates, XArI(+)Ar'Y TsO(-) (X = H or p-MeO), were investigated in a microfluidic apparatus for their reactivity towards radiofluorination with high specific activity (no-carrier-added) [(18)F]fluoride ion in mixtures of DMF and irradiated target [(18)O]water in the absence of cryptand. Salts bearing a para or ortho electron-withdrawing group Y (e.g., Y = p-CN) reacted rapidly (∼3 min) to give the expected major [(18)F]fluoroarene product, [(18)F]FArY, in useful moderate radiochemical yields even when the solvent had an [(18)O]water content up to 28%. Salts bearing electron-withdrawing groups in meta position (e.g., Y = m-NO2), or an electron-donating substituent (Y = p-OMe), gave low radiochemical yields under the same conditions.

No-carrier-added [18F]fluoroarenes from the radiofluorination of diaryl sulfoxides

No-carrier-added [(18)F]fluoroarenes were synthesized through the radiofluorination of diaryl sulfoxides with [(18)F]fluoride ion. Diaryl sulfoxides bearing a para electron-withdrawing substituent readily gave the corresponding 4-[(18)F]fluoroarenes in high RCYs. This process broadens the scope for preparing novel (18)F-labeling synthons and PET radiotracers.

Selective syntheses of no-carrier-added 2- and 3-[18F]fluorohalopyridines through the radiofluorination of halopyridinyl(4'-methoxyphenyl)iodonium tosylates

No-carrier-added 2- and 3-[(18)F]fluorohalopyridines were readily synthesized as potentially useful labeling synthons for prospective PET radiotracers through the selective radiofluorination of halopyridinyl(4'-methoxyphenyl)iodonium tosylates, themselves conveniently prepared in a single pot from iodohalopyridines.

Regiospecific syntheses of functionalized diaryliodonium tosylates via [hydroxy(tosyloxy)iodo]arenes generated in situ from (diacetoxyiodo)arenes

Ready access to (18)F-labeled aryl synthons is required for preparing novel radiotracers for molecular imaging with positron emission tomography. Diaryliodonium salts react with cyclotron-produced no-carrier-added [(18)F]fluoride ion to produce [(18)F]aryl fluorides. We aimed to prepare functionalized diaryliodonium salts to serve as potential precursors for producing useful (18)F-labeled aryl synthons, such as (18)F-labeled halomethylbenzenes, benzaldehydes, and benzoic acid esters. Such salts were designed to have one functionalized aryl ring, one relatively electron-rich ring, such as 4-methoxyphenyl or 2-thienyl, and a nonfluorine containing weakly nucleophilic anion. Generation of a [hydroxy(tosyloxy)iodo]arene from a functionalized (diacetoxyiodo)arene in situ followed by treatment with an electron-rich arene, such as anisole or thiophene, or with a functionalized arylstannane gave expedient regiospecific access to a wide range of functionally diverse diaryliodonium tosylates in moderate to high yields (44-98%). The described methodology broadens the scope for producing new functionalized diaryliodonium salts for diverse applications.

Syntheses of mGluR5 PET radioligands through the radiofluorination of diaryliodonium tosylates

3-Fluoro-1-((thiazol-4-yl)ethynyl)benzenes constitute an important class of high-affinity metabotropic glutamate subtype 5 receptor (mGluR5) ligands, some of which have been labeled with fluorine-18 (t(1/2) = 109.7 min), to provide radioligands for molecular imaging of brain mGluR5 in living animal and human subjects with positron emission tomography (PET). Labeling in the 3-fluoro position of such ligands can be achieved through aromatic nucleophilic substitution of a halide leaving group with [(18)F]fluoride ion when a weakly activating m-nitrile group is present, but is generally very low yielding (<8%). Here we used a microfluidic reaction platform to show that greatly enhanced (up to 6-fold) radiochemical yields can be achieved from suitably synthesized diaryliodonium tosylate precursors. The presence of a m-nitrile or other activating group is not required. Similar conditions were adopted in a more conventional automated radiochemistry platform having a single-pot reactor, to produce mGluR5 radioligands with useful radioactivities for PET imaging.

Rapid and Efficient Radiosyntheses of Meta-substituted [F]Fluoroarenes from [F]Fluoride Ion and Diaryliodonium Tosylates within a Microreactor

Effective methods for the introduction of the short-lived positron-emitter fluorine-18 (t(1/2) = 109.7 min) at high specific radioactivity into fluoroarenes are valuable for the development of radiotracers for molecular imaging with positron emission tomography. Here we have explored the scope of the radiofluorination of diaryliodonium salts with no-carrier-added [(18)F]fluoride ion for the preparation of otherwise difficult to access meta-substituted [(18)F]fluoroarenes. A microfluidic reaction platform was used to establish optimal radiochemical yields. Rapid, high yielding and selective radiofluorinations were achieved in unsymmetrical diaryliodonium tosylates (ArI(+)Ar'TsO(-)) in which Ar carried either a meta electron-withdrawing (CN, NO(2), CF(3)) or a meta electron-donating (Me or MeO) group, and in which the partner aryl group (Ar') was relatively electron-rich, such as Ph, 3-Me-C(6)H(4), 4-MeO-C(6)H(4), 2-thienyl or 5-Me-2-thienyl. The radiofluorination of appropriate diaryliodonium tosylates is therefore a generally useful method for the preparation of simple [(18)F]m-fluoroarenes ([(18)F]ArF).

Conformational structure and energetics of 2-methylphenyl(2'-methoxyphenyl)iodonium chloride: evidence for solution clusters

Diaryliodonium salts allow the efficient incorporation of cyclotron-produced [(18)F]fluoride ions into electron-rich and electron-deficient arenes to provide potential radiotracers for molecular imaging in vivo with positron emission tomography (PET). This process (ArI(+)Ar'+(18)F(-)→Ar(18)F+Ar'I) is still not well understood mechanistically. To better understand this and similar reactions, it would be valuable to understand the structures of diaryliodonium salts in organic media, where the reactions are typically conducted. In this endeavor, the X-ray structure of a representative iodonium salt, 2-methylphenyl(2'-methoxyphenyl)iodonium chloride (1), was determined. Our X-ray structure analysis showed 1 to have the conformational M-P dimer as the unit cell with hypervalent iodine as a stereogenic center in each conformer. With the ab initio replica path method we constructed the inversion path between the two enantiomers of 1, thereby revealing two additional pairs of enantiomers that are likely to undergo fast interconversion in solution. Also LC-MS of 1 showed the presence of dimeric and tetrameric anion-bridged clusters in weak organic solution. This observation is consistent with the energetics of 1, both as monomeric and dimeric forms in MeCN, calculated at the B3LYP/DGDZVP level. These evidences of the existence of dimeric and higher order clusters of 1 in solution are relevant to achieve a deeper general understanding of the mechanism and outcome of reactions of diaryliodonium salts in organic media with nucleophiles, such as the [(18)F]fluoride ion.

Fast and high-yield microreactor syntheses of ortho-substituted [(18)F]fluoroarenes from reactions of [(18)F]fluoride ion with diaryliodonium salts

A microreactor was applied to produce ortho-substituted [(18)F]fluoroarenes from the reactions of cyclotron-produced [(18)F]fluoride ion (t(1/2) = 109.7 min) with diaryliodonium salts. The microreactor provided a very convenient means for running sequential reactions rapidly with small amounts of reagents under well-controlled conditions, thereby allowing reaction kinetics to be followed and Arrhenius activation energies (E(a)) to be measured. Prepared symmetrical iodonium chlorides (Ar(2)I(+)Cl(-)) rapidly (<4 min) gave moderate (Ar = 2-MeOC(6)H(4), 51%) to high (Ar = Ph or 2-MeC(6)H(4), 85%) decay-corrected radiochemical yields (RCYs) of a single radioactive product (Ar(18)F). Reaction velocity with respect to Ar group was 2-MeOC(6)H(4) < Ph < 2-MeC(6)H(4). Activation energies were in the range 18-28 kcal/mol. Prepared unsymmetrical salts (e.g., 2-RC(6)H(4)I(+)2'-R'C(6)H(4)X(-); X = Cl or OTs) also rapidly gave two products (2-RC(6)H(4)(18)F and 2-R'C(6)H(4)(18)F) in generally high total RCYs (79-93%). Selectivity for product [(18)F]fluoroarene was controlled by the nature of the ortho substituents. The power of ortho substituents to impart an ortho-effect was in the following order:, 2,6-di-Me > 2,4,6-tri-Me > Br > Me > Et approximately (i)Pr >> H > OMe. For (2-methyphenyl)(phenyl)iodonium chloride, the time-course of reaction product selectivity was constant and consistent with the operation of the Curtin-Hammett principle. These results will aid in the design of diaryliodonium salt precursors to (18)F-labeled tracers for molecular imaging.

Fluorine-18 chemistry in micro-reactors

Recent applications of micro-reactor (microfluidics) technology to radiofluorination chemistry within our laboratory are presented, based on use of either a simple T-shaped glass micro-reactor or a more advanced microfluidics instrument. The topics include reaction optimization and radioligand production, in particular the study of the radiofluorination of diaryliodonium salts, [(18)F]fluoride ion exchange with xenon difluoride(,) esterification with [(18)F]2-fluoroethyl tosylate, and the syntheses of [(18)F]fallypride, [(18)F]FBR and [(18)F]SL702 from [(18)F]fluoride ion.

Electrophilic chemistry of thia-PAHs: stable carbocations (NMR and DFT), S-alkylated onium salts, model electrophilic substitutions (nitration and bromination), and mutagenicity assay

First examples of stable carbocations are reported from several classes of thia-PAHs with four fused rings, namely, benzo[b]naphtho[2,1-d]thiophene (1) and its 3-methoxy derivative (2), phenanthro[4,3-b]thiophene (3) and its 7-methoxy (4), 10-methoxy (5), and 9-methoxy (6) derivatives, phenanthro[3,4-b]thiophene (7) and its 7-methoxy (8) and 9-methoxy (9) derivatives, and 3-methoxybenzo[b]naphtha[1,2-d]thiophene (11). In several cases, the resulting carbocations were also studied by GIAO-DFT. Charge delocalization modes in the resulting carbocations were probed. A series of S-alkylated onium tetrafluoroborates, namely, 1Me+, 1Et+, 2Et+, and 7Me+ (from 1, 2, and 7), 10Me+ and 10Et+ (from benzo[b]naphtha[1,2-d]thiophene 10), 12Me+ and 12Et+ (from phenanthro[3,2-b][1]benzothiophene 12), 13Me+ (from 3-methoxyphenanthro[3,2-b]benzothiophene 13), 14Me+ (from phenanthro[4,3-b][1]benzothiophene 14), and 15Me+ (from 3-methoxyphenanthro[4,3-b][1]benzothiophene 15), were synthesized. PAH-sulfonium salts 1Me+, 1Et+, 10Me+, 10Et+, 12Me+, and 14Me+ proved to be efficient akylating agents toward model nitrogen nucleophile receptors (imidazole and azaindole). Facile transalkylation to model nucleophiles (including guanine) is also supported by favorable reaction energies computed by DFT. Ring opening energies in thia-PAH-epoxides from 1, 3, and 7 and charge delocalization modes in the resulting carbocations were also evaluated. The four-ring-fused thia-PAHs 1, 2, 3, 4, 5, 7, 8, and 11 are effectively nitrated under extremely mild conditions. Nitration regioselectivity corresponds closely to protonation under stable ion conditions. Bromination of 4 and 6 is also reported. Comparative mutagenicity assays (Ames test) were performed on 1 versus 1NO2, 5 versus 5NO2, and 11 versus 11NO2. Compound 5NO2 was found to be a potent direct acting mutagen.

Phase II study of docetaxel and irinotecan combination chemotherapy in metastatic gastric carcinoma

The current treatment for metastatic gastric cancer (MGC) consists of cisplatin and/or fluorouracil (5-FU) based combination chemotherapy, but cisplatin-based regimens are associated with considerable toxicity. We evaluated the efficacy and safety of a noncisplatin-, non-5-FU-containing regimen, docetaxel/irinotecan in MGC. Chemo-naive patients with MGC received docetaxel (30 mg m(-2)) and irinotecan (70 mg m(-2)) on days 1 and 8 every 3 weeks. The 48 eligible patients (median age 56 years) received a median of four cycles of docetaxel/irinotecan (range 1-18). Of the 46 patients in whom efficacy could be evaluated, 21 showed a partial response (response rate=45.7%; 95% confidence interval (CI) 31.3-60.1%). At a median follow-up of 15.0 months, the median time to progression was 4.5 months (95% CI 3.8-5.2 months) and overall survival was 8.2 months (95% CI, 5.8-10.6 months). Grade 3/4 neutropenia developed in 57.4% of patients, and febrile neutropenia/neutropenic infection in 19.1%. Nonhaematological toxicities were moderate; grade 3/4 diarrhoea occurred in 19.1% of patients, however, was manageable by a dose reduction. There was one possible treatment-related death. In conclusion, weekly docetaxel/irinotecan is a promising outpatient regimen in MGC, with appropriate dose modification.

Nitric oxide synthesis and severity of human periodontal disease

The expression of the inducible nitric oxide synthase enzyme (iNOS) is a response to an inflammatory stimulus and produces a large amount of nitric oxide (NO), which may act as a cytotoxic molecule against the invading microorganism and may be related to both harmful and beneficial effects to tissues.

OBJECTIVE AND MATERIAL AND METHODS

In order to further characterize the presence of NO in human periodontal disease, we undertook a quantitative study of iNOS positive cells in samples of clinically healthy gingival tissues, plaque-induced gingivitis and localized chronic periodontitis using immunohistochemistry.

RESULTS

A significant increase in the number of iNOS+ cells mm-2 was found in the samples of the gingivitis and periodontitis compared with those of the control. In all groups most of the polymorphonuclear cells showed intense immunoreactivity for iNOS independent of the disease stage, and the percentage of iNOS+ polymorphonuclear cells increased significantly in periodontal disease when compared with the control.

CONCLUSION

Our results indicate that iNOS increases in the presence of periodontal disease. In addition, our findings suggest that polymorphonuclear cells present an additional activation pathway in periodontal disease, expressing significant iNOS and probably representing an important source of NO in human periodontal disease that has not been previously reported.

Analysis of polymorphic region of GAM-1 gene in Plasmodium vivax Korean isolates

The identification, characterization and quantification of Plasmodium sp. genetic polymorphism are becoming increasingly important in the vaccine development. We investigated polymorphism of Plasmodium vivax GAM-1 (PvGAM-1) gene in 30 Korean isolates. The polymorphic region of the PvGAM-1 gene, corresponding to nt 3792-4029, was amplified using polymerase chain reaction (PCR) followed by sequencing. All of the P. vivax Korean isolates were one type of GAM-1 gene, which were identical to that of the Belem strain. It is suggested that PvGAM-1 could not be used as a genetic marker for identifying or classifying P. vivax Korean isolates. It revealed that the polymorphic pattern was acquired basically by duplication and modification or deletion event of a 33 bp-motif fragment ended by poly guanine (G) and that there were at least three complete and one partial 33 bp-motif sequences within the polymorphic region in the longest cases such as those of South Korean and Belem isolates. In addition, we clustered P. vivax isolates with parsimonious criteria on the basis of PvGAM-1 polymorphic patterns (insertion/deletion patterns).

Characterization of monoclonal antibodies against carcinoembryonic antigen (CEA) and expression in E. coli

Eight monoclonal antibodies (MAbs) against carcinoembryonic antigen (CEA) were characterized. Five clones are IgG(1), two clones are IgM and one clone is IgG(2b); all have kappa light chain. The affinities are in the range of 1.1 x 10(-7) approximately 2.4 x 10(-9) M; the affinities of two IgM clones could not be estimated because of their low enzyme-linked immunoadsorbent assay (ELISA) signal. Each clone was constructed as single-chain Fv (scFv) and expression was performed in E. coli. Four clones out of 8 could express scFv soluble to culture media and the expression was confirmed further by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting. The nucleotide and amino acid sequences of V(H) and V(L) of four scFvs were deduced and their family and subgroup were analyzed. We found that the clones that do not express the scFv have aberrant kappa chain (incorrect V/J recombination or stop codon); in contrast, their heavy chain sequences proved correct. The E. coli-expressed scFvs showed 1.5 x 3.4-fold lower affinities (2.8 x 10(-8) approximately 3.6 x 10(-9) M) than those of hybridoma-derived parental antibodies except the one clone (C5), which exhibited approximately 10(-6) M of affinity.

The -238 tumor necrosis factor-alpha promoter polymorphism is associated with decreased susceptibility to cancers

We investigated the potential association of tumor necrosis factor-alpha (TNF-alpha) promoter polymorphisms with cancers. The study included 169 patients with gastric cancer, uterine cervical cancer, colorectal cancer, or renal cell carcinoma and 92 healthy controls. The -308 and -238 polymorphisms in the TNF-alpha promoter were analyzed by PCR-restriction fragment length polymorphism (RFLP). The proportion of individuals carrying the TNF-238A allele was significantly lower in the cancer group than in the control group. The odds ratio for cancer in subjects with the TNF-238A allele was 0.25 (95% CI, 0.10-0.64). No association was found between the -308 polymorphism and cancers. These results suggest that the -238A allele has a protective function against cancers.

Use of solvents in industries in Korea: experience in Sinpyeong-Jangrim industrial complex

OBJECTIVES

To identify the most popular solvent and typical type of solvent work among solvent-using workplaces in Korea.

METHODS

In practice, 862 solvent-using workshops in Sinpyeong-Jangrim industrial complex in Pusan were investigated in a 2-year period from March 1995 to February 1997. Solvent vapors in the breathing zone of workers were collected by personal sampling with charcoal tubes. The exposed charcoal was extracted with carbon disulfide, and the solvents in the extract were analyzed by flame ionization detector-equipped gas chromatography (FID-GC).

RESULTS

Solvents were used in painting, glue application, cleaning, printing and solvent-mixing workshops in decreasing order of popularity. Toluene was the most frequently measured solvent. In the five types of solvent work, acetone, hexane, methyl ethyl ketone, methyl isobutyl ketone, tetrachloroethylene, trichloroethylene and xylenes were also used frequently.

CONCLUSIONS

Toluene was identified as the most frequently used solvent in solvent works in Korean manufacture industries in the late 1990s. Eight types of solvent were popularly used in five popular types of solvent work. These trends are very similar to the cases reported for industries in Japan.

Clinical features of 31 patients with systemic contact dermatitis due to the ingestion of Rhus (lacquer)

In Korea, Rhus has been used as a folk medicine to cure gastrointestinal diseases and as a health food. We review the clinicopathological and laboratory findings in patients with systemic contact dermatitis caused by intake of Rhus. We reviewed medical records and histopathological sections from 31 patients during a 10-year period. The male/female ratio was 1.4: 1 and the average age was 43.8 years (range 22-70). Ten patients (32%) had a known history of allergy to lacquer. Rhus was ingested to treat gastrointestinal problems including indigestion and gastritis (45%), and as a health food (39%), in cooked meat, in herbal medicine, or taken by inhalation. The patients developed skin lesions such as a maculopapular eruption (65%), erythema multiforme (EM, 32%), erythroderma (19%), pustules, purpura, weals and blisters. Erythroderma was very frequent in patients with a known history of allergy to lacquer, but maculopapular and EM-type eruptions were more frequently observed in those without a history of allergy. All patients experienced generalized or localized pruritus. Other symptoms included gastrointestinal problems (32%), fever (26%), chills and headache; many developed leucocytosis (70%) with neutrophilia (88%), while some showed toxic effects on liver and kidney. Fifty-nine per cent of patients observed cutaneous or general symptoms within a day after ingestion of Rhus. There was no difference in the time lag for symptoms to develop between patients allergic and not allergic to Rhus. All patients responded well to treatment with systemic steroids and antihistamines. Common histopathological findings were vascular dilatation, perivascular lymphohistiocytic infiltration, and extravasation of red blood cells in the upper dermis. Rhus lacquer should not be ingested in view of its highly allergic and toxic effects.

The Korean collaborative study on 11,000 prenatal genetic amniocentesis

Since amniocentesis made prenatal diagnosis feasible in 1967, the method has been remarkably instrumental in obstetrical practice. A recent study conducted between 1980 and 1997 collected 11,000 amniocentesis procedures done at 10 university hospitals and tertiary centers in Korea. The study indicated that the use of amniocentesis on patients has increased steadily since 1980; however, the number has increased sharply for patients in the mid 1990's. In the 1980's, amniocentesis had been used primarily for patients in advanced maternal age groups (at least 35 years or older). In 1995, amniocentesis had been implemented for the detection of abnormal serum markers (37.6%), and by 1997, amniocentesis was involved in such diagnosis even more frequently (44.8%). Of the total number of uses, 270 (2.5%) involved the detection of chromosomal anomaly. In autosomal disorders, 96 Down syndrome, 33 Edward syndrome, and 6 Patau syndrome were diagnosed. In sex chromosomal anomaly, 10 Turner syndrome, and 10 Klinefelter syndrome were diagnosed. Added to that, 83 translocations, and 15 mosaicisms were diagnosed. Of the 322 cases with abnormal ultrasonographic findings, 21 (6.5%) resulted in chromosomal anomaly. The use of genetic amniocentesis as a prenatal diagnostic test for Korean women has risen 10-fold between 1988 and 1998. As stated earlier, amniocentesis had earlier been used primarily for those in advanced maternal age groups. Today, maternal serum markers and highly sensitive ultrasonic technology can detect many fetal anomalies which eventually necessitate amniocentesis.

Multichannel acousto-optic Bragg cell for real-time electroholography

A multichannel acousto-optic Bragg cell was made by the joining of acousto-optic cells that have the shape of symmetrical trapezoidal prisms. This acousto-optic Bragg cell has an aperture length equal to the sum of its component acousto-optic cells but has an aperture time equal to that of each acousto-optic cell. We tested the performance of the multichannel acousto-optic Bragg cell by joining six TeO(2) acousto-optic cells together with 300-microm gaps between one another. The holographic fringe data prepared by computer were divided into six equal segments. Each data segment was again divided into six equal parts and then fed into the corresponding acousto-optic cell. The holographic images were reconstructed by the periodical illumination of a green (lambda = 0.5145 microm) pulse laser beam onto the multichannel acousto-optic Bragg cell. The reconstructed images are sharp and clear. This indicates that the multichannel acousto-optic Bragg cell is working properly.

Nrg1 is a transcriptional repressor for glucose repression of STA1 gene expression in Saccharomyces cerevisiae

Expression of genes encoding starch-degrading enzymes is regulated by glucose repression in the yeast Saccharomyces cerevisiae. We have identified a transcriptional repressor, Nrg1, in a genetic screen designed to reveal negative factors involved in the expression of STA1, which encodes a glucoamylase. The NRG1 gene encodes a 25-kDa C2H2 zinc finger protein which specifically binds to two regions in the upstream activation sequence of the STA1 gene, as judged by gel retardation and DNase I footprinting analyses. Disruption of the NRG1 gene causes a fivefold increase in the level of the STA1 transcript in the presence of glucose. The expression of NRG1 itself is inhibited in the absence of glucose. DNA-bound LexA-Nrg1 represses transcription of a target gene 10.7-fold in a glucose-dependent manner, and this repression is abolished in both ssn6 and tup1 mutants. Two-hybrid and glutathione S-transferase pull-down experiments show an interaction of Nrg1 with Ssn6 both in vivo and in vitro. These findings indicate that Nrg1 acts as a DNA-binding repressor and mediates glucose repression of the STA1 gene expression by recruiting the Ssn6-Tup1 complex.

Left main coronary artery dissection after blunt chest trauma presented as acute anterior myocardial infarction: assessment by intravascular ultrasound: a case report

Coronary artery injury after blunt chest trauma is very rare, but this can result in a serious acute myocardial infarction. Coronary artery dissection is an uncommon complication of thoracic injuries. We report a case of a 17-year-old male who was presented with an anterior myocardial infarction following blunt chest trauma after a bicycle accident. His coronary angiography revealed aneurysmal dilatation with dissection of the distal left main stem coronary artery. Intravascular ultrasound showed a dissecting flap at the left main stem coronary artery. The patient was treated conservatively and discharged without serious sequelae. When symptoms and electrocardiographic findings are compatible with acute myocardial infarction, careful evaluation is important in patients with thoracic injuries for proper management. If the patient is stable, medical therapy may be appropriate. But early intervention should be considered in the presence of ongoing myocardial ischemia.

Cell growth on microcarriers: comparison of proliferation on and recovery from various substrates

Three commercially-important types of cell were grown on four different microcarrier substrates. The cells, which included normal human diploid fibroblasts (MRC-5), primary chick embryo cells and Madin-Darby bovine kidney cells (MDBK), were compared with regard to proliferation on the substrates and with regard to recovery of viable cells from the same substrates. The substrates used included glass-coated microcarriers (Biosil), collagen microcarriers (Ventregel), DEAE-dextran microcarriers (Cytodex I) and collagen-linked DEAE-dextran microcarriers (Cytodex III). The established cell line (MDBK) grew well on all of the substrates and a high percentage of viable cells could be harvested from each substrate. The MRC-5 cells also grew well on all four substrates but high recovery rates were achieved only with cells grown on the glass-coated microcarriers or collagen microcarriers. In contrast, the primary chick embryo cells grew well only on the glass microcarriers and the recovery rate of cells harvested from this substrate was high. In some industrial operations, the re-utilization of cells after removal from the substrate is necessary. In these situations the appropriate choice of microcarriers for the cultivation of the cells may be critical.

Doughnut sign on bone scintigraphy in angioblastic meningioma

Bone imaging was performed in a patient with a rapidly expanding parietal bone lesion. The findings on the nuclear medicine study showed a doughnut type lesion. The underlying abnormality was found to be an angioblastic meningioma causing local bone destruction.

Inactivated poliovirus vaccine and test development at Connaught Laboratories Ltd

Trivalent inactivated poliovirus vaccine (IPV) (MK) was made, purified, and inactivated according to the amended Rijks Instituut (The Netherlands) protocol from primary monkey kidney tissue grown on microcarrier cultures. Losses of the type 2 component due to adsorption to the glass ampule occurred with the purified vaccine preparation. This problem was solved by changing the diluent, and the vaccine was submitted for evaluation in clinical trials at Johns Hopkins (Baltimore, Md.). Phase 2 of the development was to standardize production of IPV from MRC-5 (human diploid) cells on microcarriers and otherwise follow the Rijks Instituut 's method. Results of experimental trivalent vaccine production and testing showed that the number of effective doses harvested from MRC-5 cell cultures compared favorably with vaccine derived from monkey kidney. The yields could be further increased with stearyl tyrosine as adjuvant. Large-scale production using 200-liter fermenters is in progress. Poliovirus particles of various densities in cesium chloride can be found in any IPV preparation and give rise to different immunogenic responses. As shown in this paper, some of these virus fractions produce a low primary humoral antibody response but appear to be important for memory induction.