School of Medical Sciences
Permanent URI for this community
The School of Medical Sciences encompasses the disciplines of Anatomical Sciences, Pathology and Pharmacology.
Browse
Browsing School of Medical Sciences by Title
Now showing 1 - 20 of 3067
Results Per Page
Sort Options
Item Metadata only 2,000 Year old β-thalassemia case in Sardinia suggests malaria was endemic by the Roman period(Wiley, 2017) Viganó, C.; Haas, C.; Rühli, F.J.; Bouwman, A.Objectives: The island of Sardinia has one of the highest incidence rates of β-thalassemia in Europe due to its long history of endemic malaria, which, according to historical records, was introduced around 2,600 years ago by the Punics and only became endemic around the Middle Ages. In particular, the cod39 mutation is responsible for more than 95% of all β-thalassemia cases observed on the island. Debates surround the origin of the mutation. Some argue that its presence in the Western Mediterranean reflects the migration of people away from Sardinia, others that it reflects the colonization of the island by the Punics who might have carried the disease allele. The aim of this study was to investigate β-globin mutations, including cod39, using ancient DNA (aDNA) analysis, to better understand the history and origin of β-thalassemia and malaria in Sardinia. Materials and Methods: PCR analysis followed by sequencing were used to investigate the presence of β-thalassemia mutations in 19 individuals from three different Roman and Punic necropolises in Sardinia. Results: The cod39 mutation was identified in one male individual buried in a necropolis from the Punic/Roman period. Further analyses have shown that his mitochondrial DNA (mtDNA) and Ychromosome haplogroups were U5a and I2a1a1, respectively, indicating the individual was probably of Sardinian origin. Conclusions: This is the earliest documented case of b-thalassemia in Sardinia to date. The presence of such a pathogenic mutation and its persistence until present day indicates that malaria was likely endemic on the island by the Roman period, earlier than the historical sources suggest.Item Open Access 3,4-Methylenedioxymethamphetamine (MDMA) induced hyperthermia - the role of pro-inflammatory cytokines(Bentham Open, 2011) Salem, A.; Gordon, J.; Hutchinson, M.; Irvine, R.Item Metadata only 3D printed lattices as an activation and expansion platform for T cell therapy(Elsevier, 2017) Delalat, B.; Harding, F.; Gundsambuu, B.; De-Juan-Pardo, E.; Wunner, F.; Wille, M.; Jasieniak, M.; Malatesta, K.; Griesser, H.; Simula, A.; Hutmacher, D.; Voelcker, N.; Barry, S.Abstract not availableItem Metadata only 5-HT₁B receptor modulation of the serotonin transporter in vivo: studies using KO mice(Pergamon-Elsevier Science Ltd, 2014) Montanez, S.; Munn, J.; Owens, W.; Horton, R.; Daws, L.Item Metadata only 5-hydroxymethyl-furfural and structurally related compounds block the ion conductance in human aquaporin-1 channels, and slow cancer cell migration and invasion(American Society for Pharmacology and Experimental Therapeutics, 2020) Chow, P.H.; Kourghi, M.; Pei, J.V.; Nourmohammadi, S.; Yool, A.J.Aquaporin-1 (AQP1) dual water and ion channels enhance migration and invasion when upregulated in leading edges of certain classes of cancer cells. Work here identifies structurally-related furan compounds as novel inhibitors of AQP1 ion channels. 5-Hydroxymethyl-2-furfural (5HMF), a component of natural medicinal honeys, and three structurally-related compounds nitrofuroic acid (5NFA), acetoxymethylfuraldehyde (5AMF), and methylnitrofuroate (M5NF), were analyzed for effects on water and ion channel activities of human AQP1 channels expressed in Xenopus oocytes. Two-electrode voltage clamp showed dose-dependent block of the AQP1 ion current by 5HMF (IC50 0.43 mM ), 5NFA (IC50 1.2 mM), 5AMF (IC50 ~3 mM), but no inhibition by M5NF. In silico docking predicted the active ligands interacted with glycine 165, located in loop D gating domains surrounding the intracellular vestibule of the tetrameric central pore. Water fluxes through separate intrasubunit pores were unaltered by the furan compounds (at concentrations up to 5mM). Effects on cell migration, invasion and cytoskeletal organization in vitro were tested in high AQP1-expressing cancer lines, HT29 and MDA, and low AQP1-expressing SW480. 5HMF, 5NFA and 5AMF selectively impaired cell motility in the AQP1-enriched cell lines. In contrast M5NF immobilized all the cancer lines by disrupting actin cytoskeleton. No reduction in cell viability was observed at doses that were effective in blocking motility. These results define furans as a new class of AQP1 ion channel inhibitors for basic research, and potential lead compounds for development of therapeutic agents targeting aquaporin channel activity. SIGNIFICANCE STATEMENT: 5-hydroxymethyl furfural (5HMT), a component of natural medicinal honeys, blocks the ion conductance but not the water flux through human Aquaporin-1 (AQP1) channels, and impairs AQP1-dependent cell migration and invasiveness in cancer cell lines. Analyses of 5HMT and structural analogs demonstrate a structure-activity relationship for furan compounds, supported by in silico docking modeling. This work identifies new low-cost pharmacological antagonists for AQP1 available to researchers internationally. Furans merit consideration as a new class of therapeutic agents for controlling cancer metastasis.Item Metadata only 5-hydroxytryptamine-induced contraction of the marmoset aorta is mediated by a 5-HT-1 like receptor.(BLACKWELL SCIENCE, 1998) Dyer, S.; de la Lande, I.; Frewin, D.; Head, R.1. 5-Hydroxytryptamine (5-HT) exerts both contractile and relaxant effects in the marmoset isolated aorta, actions that are unaffected by the 5-HT[sub 2] antagonist ketanserin. The aim of the present study was to define the receptors mediating the contractile activity of 5-HT in the marmoset aorta. 2. Contractile responses were elicited in aortic rings that were either: (i) precontracted submaximally with the thromboxane A[sub 2] agonist U44069 in order to amplify the responses; or (ii) exposed to N[sup ω]-nitro-L-arginine (100 µmol/L) plus LY53857 (0.1 µmol/L; a 5-HT[sub 2] receptor antagonist shown previously to inhibit relaxation). The effect of 5-HT on adenosine 3',5'-cyclic monophosphate (cAMP) formation was also investigated. 3. The effects of agonists and antagonists comprised: (i) agonist potencies in the order 5-carboxamidotryptamine > 5-HT > sumatriptan > 8-hydroxy-2-(di-n-propylamino)tetralin; (ii) inhibition of contractile action of 5-HT by the 5-HT[sub 1D] antagonist GR 127935; (iii) a contractile response to methysergide; (iv) a lack of effect of tropisetron, an antagonist of 5-HT[sub 3] and 5-HT[sub 4] receptors; and (v) inhibition of forskolin-stimulated cAMP formation by 5-HT (in the presence of LY 53857), indicative of negative coupling to adenylate cyclase. 4. The above effects fulfil the criteria for a 5-HT[sub 1]-like receptor. In view of the previous finding that this contractile response is insensitive to ketanserin, it is concluded that the contractile effects of 5-HT in the marmoset aorta are mediated exclusively by a 5-HT[sub 1]-like receptor.Item Metadata only 99mTc-alafosfalin: an antibiotic peptide infection imaging agent(Elsevier Science Inc, 2003) Tsopelas, C.; Penglis, S.; Ruszkiewicz, A.; Bartholomeusz, F.The radiolabeled antibiotic peptide (99m)Tc-alafosfalin was assessed as an infection imaging agent in a rat model by comparison with (99m)Tc-DTPA and (99m)Tc-leukocytes. (99m)Tc-alafosfalin was prepared via an instant cold kit and (99m)Tc-leukocytes were prepared using (99m)Tc-stannous fluoride colloid in an ex vivo labeling procedure of whole blood. In separate experiments, the three radiotracers were administered to rats infected with staphylococcus aureus. Quantitative biodistribution studies were performed as well as scintigraphic images and histopathology. (99m)Tc-alafosfalin is a stable product, obtained in high radiochemical purity (>95%). This agent was mainly renally excreted, with low liver, spleen and bone uptake, and resulted in a mean ratio of infected/non-infected thighs of 4.3/1.0 at 4 hr post radiotracer injection. (99m)Tc-DTPA gave a corresponding ratio of 1.9/1.0 and (99m)Tc-leukocytes gave 20.0/1.0 at the same time point. An in vitro assay found the level of (99m)Tc-alafosfalin binding to staphylococcus aureas higher than (99m)Tc-DTPA (10% versus 1% respectively). (99m)Tc-alafosfalin accumulates at sites of infection in a rat model better than the perfusion molecule (99m)Tc-DTPA, yet less than (99m)Tc-leukocytes. The distribution characteristics of this (99m)Tc-antibiotic peptide would be an advantage in imaging abdominal and soft tissue infection.Item Metadata only 99mTc-Evans blue dye for mapping contiguous lymph node sequences and discriminating the sentinel lymph node in an ovine model(Lippincott Williams & Wilkins, 2006) Tsopelas, C.; Bevington, E.; Kollias, J.; Shibli, S.; Farshid, G.; Coventry, B.; Chatterton, B.Background: The aim of this study was to investigate the potential of 99mTc–Evans blue for discriminating the sentinel lymph node in multitiered lymph node sequences by using an ovine model. 99mTc–Evans blue is an agent that has both radioactive and color signals in a single dose. Previous studies in smaller animal models suggested that this agent could have advantages over the dual-injection technique of radiocolloid/blue dye. Methods: Doses of 99mTc–Evans blue (∼ 21 MBq) containing Evans blue dye (approximately 4 mg) were administered to the hind limbs or fore limbs of sheep to map the lymphatic drainage patterns, validate its ability to identify the sentinel lymph node, and examine the reproducibility of the technique. The study protocol was repeated with 99mTc–antimony trisulfide colloid and Patent Blue V dye. After the operative exposure, lymph nodes were identified with the gamma probe and then excised and analyzed for radioactivity (percentage of injected dose) and blue color. Results: After the administration of 99mTc–Evans blue, all lymph nodes harvested (35 of 35) in either short chains or long basins were hot and blue. The sentinel lymph nodes concentrated more radioactivity than the second-tier nodes to the extent of 2:1 to 215:1. For radiocolloid/Patent Blue V, the ratios were lower, at 2:1 to 3:1. Conclusions: 99mTc–Evans blue was found to better discriminate the sentinel lymph node than 99mTc–antimony trisulfide colloid/Patent Blue V in variable multitier lymph node anatomy, and it is an agent that promises to have positive clinical applications.Item Metadata only A Bayesian approach for population pharmacokinetic modelling of sirolimus(Blackwell Publishing Ltd, 2006) Dansirikul, C.; Morris, R.; Tett, S.; Duffull, S.Aims
To explore a Bayesian approach for the pharmacokinetic analysis of sirolimus concentration data arising from therapeutic drug monitoring (poorly informative concentration-time point design), and to explore possible covariate relationships for sirolimus pharmacokinetics.Methods
Sirolimus concentration-time data were available as part of routine clinical care from 25 kidney transplant recipients. Most samples were taken at or near the trough time point at steady state. The data were analyzed using a fully conditional Bayesian approach with PKBUGS (v 1.1)/WinBUGS (v 1.3). Features of the data included noncompliance and missing concentration measurements below the limit of sensitivity of the assay. Informative priors were used.Results
A two-compartment model with proportional residual error provided the best fit to the data (consisting of 315 sirolimus concentration-time points). The typical value for the apparent clearance (CL/F ) was 12.5 l h(-1) at the median age of 44 years. Apparent CL was found to be inversely related to age with a posterior probability of a clinically significant effect of 0.734.Conclusions
A population pharmacokinetic model was developed for sirolimus using a novel approach. Bayesian modelling with informative priors allowed interpretation of a significant covariate relationship, even using poorly informative data.Item Metadata only A brief pictorial and historical introduction to guaiacum – from a putative cure for syphilis to an actual screening method for colorectal cancer(Wiley, 2017) Eppenberger, P.; Galassi, F.; Rühli, F.Abstract not availableItem Metadata only A case of haemorrhagic myositis with concurrent anti-Ro52 and anti-NXP-2 antibodies treated with plasmapheresis(Oxford University Press, 2020) Brown, Z.R.; Thomas, J.S.; Limaye, V.Abstract not availableItem Open Access A case of pancreatic cancer in the setting of autoimmune pancreatitis with nondiagnostic serum markers(Hindawi Publishing Corporation, 2013) Chandrasegaram, M.D.; Chiam, S.C.; Nguyen, N.Q.; Ruszkiewicz, A.; Chung, A.; Neo, E.L.; Chen, J.W.; Worthley, C.S.; Brooke-Smith, M.E.Background. Autoimmune pancreatitis (AIP) often mimics pancreatic cancer. The diagnosis of both conditions is difficult preoperatively let alone when they coexist. Several reports have been published describing pancreatic cancer in the setting of AIP. Case Report. The case of a 53-year-old man who presented with abdominal pain, jaundice, and radiological features of autoimmune pancreatitis, with a "sausage-shaped" pancreas and bulky pancreatic head with portal vein impingement, is presented. He had a normal serum IgG4 and only mildly elevated Ca-19.9. Initial endoscopic ultrasound-(EUS-) guided fine-needle aspiration (FNA) of the pancreas revealed an inflammatory sclerosing process only. A repeat EUS guided biopsy following biliary decompression demonstrated both malignancy and features of autoimmune pancreatitis. At laparotomy, a uniformly hard, bulky pancreas was found with no sonographically definable mass. A total pancreatectomy with portal vein resection and reconstruction was performed. Histology revealed adenosquamous carcinoma of the pancreatic head and autoimmune pancreatitis and squamous metaplasia in the remaining pancreas. Conclusion. This case highlights the diagnostic and management difficulties in a patient with pancreatic cancer in the setting of serum IgG4-negative, Type 2 AIP.Item Metadata only A case of presumptive primary lateral sclerosis with upper and lower motor neurone pathology(Churchill Livingstone, 2005) Short, C.; Scott, G.; Blumbergs, P.; Koblar, S.Motor Neurone Disease (MND) is one of the commonest neurodegenerative disorders of adulthood. MND characteristically presents with a combination of both upper and lower motor neurone features. Primary Lateral Sclerosis (PLS) is thought to be a variant of MND presenting with purely upper motor neurone signs. Debate continues over whether PLS constitutes a distinct pathological entity or whether it is part of the spectrum of motor neurone diseases that present as an upper motor neurone-predominant form of MND. We present a case of MND with purely upper motor neurone features and a prominent pain component. A pre-mortem diagnosis of PLS was made, however autopsy findings demonstrated both upper and lower motor neurone involvement. We believe these findings support the view that PLS is not a discrete pathological entity, but that it is a part of the range of motor neurone diseases that present with predominant but not exclusive upper motor neurone involvement. This case also highlights the feature that pain may be associated with MND even though it is not appreciated to have a sensory pathology.Item Metadata only A case study of real-time monitoring of solid-state phase transformations in acoustically levitated particles using near infrared and Raman spectroscopy(Elsevier, 2013) Rehder, S.; Wu, J.X.; Laackmann, J.; Moritz, H.-U.; Rantanen, J.; Rades, T.; Leopold, C.S.The objective of this study was to monitor the amorphous-to-crystalline solid-state phase transformation kinetics of the model drug ibuprofen with spectroscopic methods during acoustic levitation. Chemical and physical information was obtained by real-time near infrared (NIRS) and Raman spectroscopy measurements. The recrystallisation kinetic parameters (overall recrystallisation rate constant β and the time needed to reach 50% of the equilibrated level t(50)), were determined using a multivariate curve resolution approach. The acoustic levitation device coupled with non-invasive spectroscopy enabled monitoring of the recrystallisation process of the difficult-to-handle (adhesive) amorphous sample. The application of multivariate curve resolution enabled isolation of the underlying pure spectra, which corresponded well with the reference spectra of amorphous and crystalline ibuprofen. The recrystallisation kinetic parameters were estimated from the recrystallisation profiles. While the empirical recrystallisation rate constant determined by NIR and Raman spectroscopy were comparable, the lag time for recrystallisation was significantly lower with Raman spectroscopy as compared to NIRS. This observation was explained by the high energy density of the Raman laser beam, which might have led to local heating effects of the sample and thus reduced the recrystallisation onset time. It was concluded that acoustic levitation with NIR and Raman spectroscopy combined with multivariate curve resolution allowed direct determination of the recrystallisation kinetics of amorphous drugs and thus is a promising technique for monitoring solid-state phase transformations of adhesive small-sized samples during the early phase of drug development.Item Open Access A cell permeable bimane-constrained PCNA-interacting peptide(Royal Society of Chemistry (RSC), 2021) Horsfall, A.J.; Vandborg, B.; Kikhtyak, Z.; Scanlon, D.B.; Tilley, W.D.; Hickey, T.E.; Bruning, J.B.; Abell, A.D.The human sliding clamp protein known as proliferating cell nuclear antigen (PCNA) orchestrates DNA-replication and -repair and as such is an ideal therapeutic target for proliferative diseases, including cancer. Peptides derived from the human p21 protein bind PCNA with high affinity via a 3₁₀-helical binding conformation and are known to shut down DNA-replication. Here, we present studies on short analogues of p21 peptides (143–151) conformationally constrained with a covalent linker between i, i + 4 separated cysteine residues at positions 145 and 149 to access peptidomimetics that target PCNA. The resulting macrocycles bind PCNA with K(D) values ranging from 570 nM to 3.86 μM, with the bimane-constrained peptide 7 proving the most potent. Subsequent X-ray crystallography and computational modelling studies of the macrocyclic peptides bound to PCNA indicated only the high-affinity peptide 7 adopted the classical 3₁₀-helical binding conformation. This suggests the 3₁₀-helical conformation is critical to high affinity PCNA binding, however NMR secondary shift analysis of peptide 7 revealed this secondary structure was not well-defined in solution. Peptide 7 is cell permeable and localised to the cell cytosol of breast cancer cells (MDA-MB-468), revealed by confocal microscopy showing blue fluorescence of the bimane linker. The inherent fluorescence of the bimane moiety present in peptide 7 allowed it to be directly imaged in the cell uptake assay, without attachment of an auxiliary fluorescent tag. This highlights a significant benefit of using a bimane constraint to access conformationally constrained macrocyclic peptides. This study identifies a small peptidomimetic that binds PCNA with higher affinity than previous reported p21 macrocycles, and is cell permeable, providing a significant advance toward development of a PCNA inhibitor for therapeutic applications.Item Metadata only A central role for venom in predation by Varanus komodoensis (Komodo Dragon) and the extinct giant Varanus (Megalania) priscus(Natl Acad Sciences, 2009) Scanlon, D.The predatory ecology of Varanus komodoensis (Komodo Dragon)has been a subject of long-standing interest and considerable conjecture. Here, we investigate the roles and potential interplay between cranial mechanics, toxic bacteria, and venom. Our analyses point to the presence of a sophisticated combined-arsenal killing apparatus. We find that the lightweight skull is relatively poorly adapted to generate high bite forces but better adapted to resist high pulling loads. We reject the popular notion regarding toxic bacteria utilization. Instead, we demonstrate that the effects of deep wounds inflicted are potentiated through venom with toxic activities including anticoagulation and shock induction. Anatomical comparisons of V. komodoensis with V.(Megalania) priscus fossils suggest that the closely related extinct giant was the largest venomous animal to have ever lived.Item Metadata only A comparative study of sperm production in two species of Australian arid zone rodents (Pseudomys australis, Notomys alexis) with marked differences in testis size(Journals of Reproduction Fertility Ltd, 2001) Peirce, E.; Breed, W.The plains rat, Pseudomys australis, and the spinifex hopping mouse, Notomys alexis, show marked differences in the size of their testes and in the number of spermatozoa within the epididymides. In the present study, the dynamics of sperm production and the duration of sperm transit along the male excurrent ducts were compared between these two species. The durations of the cycle of the seminiferous epithelium, spermatogenesis and sperm transit were determined by tracking cells using autoradiography after [(3)H]thymidine incorporation. Daily sperm production was determined from counts of testicular spermatids after homogenization and further estimates of sperm transit were obtained by dividing sperm reserves within the various regions of the extratesticular ducts by the daily sperm production of the attached testis. In the plains rat, the mean duration of the cycle of the seminiferous epithelium was 11.2 days, the duration of spermatogenesis was 45 days, daily sperm production was 2.6 x 10(7) spermatozoa per gram of testis and epididymal transit of spermatozoa took approximately 9 days (caput 0.8 days; corpus 1.5 days; cauda 6.5 days). In contrast, in the hopping mouse, the mean duration of the cycle of the seminiferous epithelium was 14 days, the duration of spermatogenesis was 56 days and daily sperm production per gram of testis was < 1.0 x 10(7). Epididymal transit of spermatozoa was completed in about 4 days (caput + corpus < 1 day; cauda 3 days); however, spermatozoa may be stored for an additional 1.5-2.0 days in the vas deferens. These results indicate that, in addition to small testes, the hopping mouse shows a low efficiency of sperm production, a relatively long duration of spermatogenesis and rapid passage of spermatozoa through the epididymis, all of which contribute to low epididymal sperm counts. These data are considered in relation to interspecific differences in sperm competition.Item Metadata only A comparison of antagonist-precipitated withdrawal under anesthesia to standard inpatient withdrawal as a precursor to maintenance naltrexone treatment in heroin users: outcomes at 6 and 12 months(Elsevier Sci Ireland Ltd, 2002) McGregor, C.; Ali, R.; White, J.; Thomas, P.; Gowing, L.To compare two methods of heroin withdrawal, 51 heroin users were randomised to undergo a 1 day precipitated withdrawal procedure using naloxone under anaesthetic. About 50 participants were randomised to receive the current standard inpatient withdrawal treatment using clonidine plus symptomatic medication. Following withdrawal, both groups were offered 9 months of naltrexone treatment and supportive counselling. Outcome measures were: commencement of naltrexone, retention in treatment and heroin use at 6 and 12 months. Significantly more of the precipitated withdrawal group completed withdrawal, commenced naltrexone and stayed in treatment for the first 3 months. Overall, there was a significant reduction in both self-reported heroin use and morphine concentration in hair over the 12 month study period, with participants in the precipitated withdrawal group showing significantly lower morphine concentration at 6 months. Being younger and having a lower level of dependence were predictors of abstinence at 6 and 12 months. The advantage of precipitated withdrawal under anesthesia did not persist beyond 3 months with respect to retention in naltrexone treatment or beyond 6 months with respect to heroin use. Long-term follow-up is crucial in assessing the effects of treatment interventions for heroin dependence.Item Metadata only A comparison of folic acid and 5-methyltetrahydrofolate for prevention of DNA damage and cell death in human lymphocytes in vitro(Oxford Univ Press, 2003) Wang, X.; Fenech, M.Folic acid (FA), the most oxidized and stable form of folate, is commonly used as a dietary supplement and in culture media. FA must be reduced and methylated to become the metabolically active form found in blood and utilized by tissues, i.e. 5-methyltetrahydrofolate (5-MeTHF). 5-MeTHF is the methyl group donor required for the conversion of homocysteine to methionine catalyzed by vitamin B(12)-dependent methionine synthase. It is hypothesized that 5-MeTHF may be more effective than FA in reducing spontaneous DNA damage and improving cell proliferation because, unlike FA, it can donate a methyl group for methionine synthesis, which is required for cell division via polyamine production and for maintenance methylation of DNA after its conversion to S-adenosylmethionine. We aimed to determine whether FA and 5-MeTHF differed in their capacity to prevent genetic damage and cell proliferation of human lymphocytes in vitro. Lymphocytes from eight female volunteers (40-48 years) were cultured in RPMI 1640 medium containing 12-120 nM FA or 5-MeTHF for 9 days. Mitogenesis was stimulated with phytohemagglutinin and the medium changed on days 3 and 6. Cytokinesis was inhibited by adding cytochalasin B on day 8 and cells were harvested and transferred to microscope slides on day 9. Chromosome damage, cell death and cytostasis was measured using the cytokinesis-block micronucleus assay in its comprehensive mode. The results showed that the frequency of micronucleated binucleate cells was significantly lower at 120 nM FA compared with 120 nM 5-MeTHF (P < 0.05), however, at 12 nM concentration both forms of folate were associated with increased frequency of micronuclei and nuclear buds relative to 120 nM (P < 0.05). Apoptosis tended to be significantly higher in 5-MeTHF cultures compared with FA cultures, however, necrosis and nuclear division were similar between cultures. We conclude that 5-MeTHF is not more efficient than FA in preventing human lymphocyte genomic instability in this in vitro system. Further research is needed to clarify the role of choline and methionine concentration and the importance of the reduced folate carrier and the folate receptor in determining the relative bioavailability of 5-MeTHF and FA with regard to genome stability.Item Metadata only A comparison of folic acid deficiency-induced genomic instability in lymphocytes of breast cancer patients and normal non-cancer controls from a Chinese population in Yunnan(Oxford Univ Press, 2006) Wang, X.; Wu, X.; Liang, Z.; Huang, Y.; Fenech, M.; Xue, J.We hypothesized that the genomic response to folate deficiency might be different between breast cancer cases and healthy subjects. To test this hypothesis, we performed a comprehensive study on the genotoxic and cytotoxic effects of in vitro folic acid (FA) deficiency on primary human lymphocytes from 19 breast cancer patients and 20 age-matched healthy females from Yunnan, China using the cytokinesis-block micronucleus assay. Lymphocytes from the volunteers were cultured in RPMI1640 medium containing 30, 120 or 240 nM FA for 9 days. The results showed that 30 nM FA was associated with increased frequencies of micronucleated binucleated cell (MNed BNC), nucleoplasmic bridges (NPB), nuclear buds (BUD), apoptosis (APO) and necrosis (NEC) relative to 120 and 240 nM FA (P<0.001) in lymphocytes of case and control groups in vitro, however there were no significant differences between the 120 and 240 nM FA within each sampling group. The case group showed significantly higher frequencies of MNed BNC than control at 120 and 240 nM FA (P<0.05-0.001) but not at 30 nM FA (P=0.052). NEC was significantly higher in breast cancer group than control at all concentrations of FA (P<0.005). FA concentration explained 60, 39, 39, 52 and 71% of the variance of MNed BNC, NPB, BUD, APO and NEC, respectively compared with breast cancer status which only explained 6 and 7% of the variance of MNed BNC and NEC(Two way ANOVA, P<0.0001). Difference of difference analysis showed that breast cancer cases were not abnormally sensitive to the genome-damaging effect of folate deficiency. We concluded that (i) increased concentrations of FA abolished the genome-damaging effect of FA deficiency in lymphocytes of both breast cancer patients and controls to a similar extent and (ii) FA concentration is much more important than breast cancer status in determining genomic instability and cell death.