Prosthetic rehabilitation of maxillary lateral incisors agenesis using dental mini-implants: a multicenter 10-year follow-up.

OBJECTIVES: Implants are used to replace congenitally missing lateral incisors but often the space across the alveolar crest is too narrow to permit their use. This multicenter study (Dental Clinic of the University of Foggia, Odontostomatology Clinic of the University of L'Aquila) evaluated the efficacy of mini-implants in cases of maxillary lateral incisor agenesis with severe osseous atrophy in 10-year follow-up. MATERIALS AND METHODS: Forty-seven mini-implants have been inserted in 35 patients affected by lateral incisors agenesis (23 single and 12 bilateral ageneses). All patients underwent orthodontic opening of the space of the upper lateral incisors. After the insertion of the implants, the immediate, non-functional loading, positioning of crowns, presence of pain during percussion and mini-implant function, horizontal and vertical movement when a force of 5 N was applied, ridge loss, and plaque index have been evaluated 1 month after loading, 1 year after loading, and then every 5 years in the following 10 years. Little's test was used to evaluate the assumption that data of loss to follow-up implants are missing completely at random (MCAR) and that a complete-case scenario could be adopted. Wilcoxon test was carried out to look statistically significant differences between the various parameters resulting in the complete-case scenario and those assumed for the worst scenario. The software R (v. 3.6.1, 2019) was employed to perform the statistical analysis. RESULTS: The results obtained over 10 years range from 89% of success rate in a worst-case scenario to the 100% using a complete-case analysis with satisfactory values of marginal bone resorption and good conditions of the peri-implant tissue. Ten-year follow-up using complete-case analysis shows survival rates of 100% for implants with no signs of peri-implantitis, stability of the marginal bone levels and soft tissue around the dental implants. CONCLUSIONS: The data collected show very good implant stability, absence of progressive peri-implantitis, and satisfactory aesthetical results in time (no signs of infraocclusion). CLINICAL RELEVANCE: Mini-implants can be considered a valid and stable over time solution in the restorative treatment of maxillary lateral incisors agenesis.

Pre-clinical evaluation of a new coral-based bone scaffold.

Coral is used worldwide for bone reconstruction. The favorable characteristics that make this material desirable for implantation are (i) osteoinduction, (ii) and osteoconduction. These proprieties have been demonstrated by in vivo studies with animal models and clinical trials over a twenty-year period. Also poly(2-hydroxyethylmethacrylate) [poly(HEMA)] is a widely used biomaterial. By using coral and poly(HEMA), a scaffold for bone reconstruction application has been recently synthesized. Cytological, histological and genetic analyses were performed to characterize this new alloplastic material. Four samples were analyzed: (a) white coral (WC), (b) red coral (RC), (c) WC plus polymer (WCP) and (d) RC plus polymer (RCP). Quantification of mitochondrial dehydrogenase activity by MTT assay was performed as indirect detector of cytotoxicity. In vivo effects were revealed by implanting corals and coral-based polymers in rabbit tibia. Samples were collected after 4 weeks and subjected to histological analysis. To evaluate the genetic response of cells to corals and coral-derived polymers an osteoblastlike cell line (i.e. MG63) was cultured in wells containing (a) medium, (b) medium plus corals and (c) medium plus two types of scaffolds (RCP or WCP). RNAs extracted from cells were retro-transcribed and hybridized on DNA 19.2K microarrays. No cytotoxicity was detected in corals and coral-based biopolymers. No inflammation or adverse effect was revealed by histological examination. By microarray analysis 154 clones were differentially expressed between RC and WC (81 up and 73 down regulated) whereas only 15 clones were repressed by the polymer. Histological evaluation not only confirmed that coral is a biocompatible material, but also that the polymer has no adverse effect. Microarray results were in agreement with cytological and histological analyses and provided further data regarding the genetic effects of RC, WC and the new polymer.

Reactive astrocytes and Wnt/ß-catenin signaling link nigrostriatal injury to repair in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine model of Parkinson's disease.

Emerging evidence points to reactive glia as a pivotal factor in Parkinson's disease (PD) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned mouse model of basal ganglia injury, but whether astrocytes and microglia activation may exacerbate dopaminergic (DAergic) neuron demise and/or contribute to DAergic repair is presently the subject of much debate. Here, we have correlated the loss and recovery of the nigrostriatal DAergic functionality upon acute MPTP exposure with extensive gene expression analysis at the level of the ventral midbrain (VM) and striata (Str) and found a major upregulation of pro-inflammatory chemokines and wingless-type MMTV integration site1 (Wnt1), a key transcript involved in midbrain DAergic neurodevelopment. Wnt signaling components (including Frizzled-1 [Fzd-1] and ß-catenin) were dynamically regulated during MPTP-induced DAergic degeneration and reactive glial activation. Activated astrocytes of the ventral midbrain were identified as candidate source of Wnt1 by in situ hybridization and real-time PCR in vitro. Blocking Wnt/Fzd signaling with Dickkopf-1 (Dkk1) counteracted astrocyte-induced neuroprotection against MPP(+) toxicity in primary mesencephalic astrocyte-neuron cultures, in vitro. Moreover, astroglial-derived factors, including Wnt1, promoted neurogenesis and DAergic neurogenesis from adult midbrain stem/neuroprogenitor cells, in vitro. Conversely, lack of Wnt1 transcription in response to MPTP in middle-aged mice and failure of DAergic neurons to recover were reversed by pharmacological activation of Wnt/ß-catenin signaling, in vivo, thus suggesting MPTP-reactive astrocytes in situ and Wnt1 as candidate components of neuroprotective/neurorescue pathways in MPTP-induced nigrostriatal DAergic plasticity.

Staged hybrid treatment of complex ascending aortic and distal aortic arch pseudoaneurysm after repair of aortic coarctation.

A 49-year-old operated for aortic coartaction patient presented with thoracic and ascending aortic aneurysm. He was asymptomatic. Angio-magnetic resonance nuclear scan and angiography revealed an ascending aortic aneurysm (5.2 cm), bicuspid aortic valve, 6-cm proximal descending aortic pseudoaneurysm at the site of the previous operation with involvement of the left subclavian artery. Restenosis at the original site of coarctation and aortic arch hypoplasia distally to the brachiocefalic trunk was also found. The operation performed was a "modified Bentall - De Bono". The pseudoaneurysm was not accessible through median sternotomy due to the massive lung adhesions following the previous surgery. The left common carotid artery was explanted from the aortic arch and connected with a graft to the ascending aortic conduit. A proximal neck suitable for landing zone of the endovascular stent-graft was then established. The postoperative course was uneventful. After two weeks, the patient was readmitted. The exclusion of the thoracic descending aortic pseudoaneurysm by endovascular implantation of the stent-graft prosthesis was performed. The left subclavian artery was excluded because left vertebral artery was closed. The patient did not develop hand claudicatio. The procedure was successful.

Friend disease in vitro.

In long-term marrow cultures, hemopoiesis can be maintained for several months, although erythropoiesis is normally suppressed at the most primitive level of development (the erythroid colony-forming cells). Infection of these cultures with a viral complex combining helper-independent murine leukemia virus (F-MuLV) and a spleen focus-forming virus (SFFVp) results in a productive infection of both the replication defective SFFVp and the F-MuLV. After infection, the cultures show a dramatic elevation in the numbers of late erythroid progenitor cells (CFU-E), many of which will grow in the absence of added erythropoietin, and a transient erythropoietin, independent erythropoiesis, including the production of mature, enucleated erythrocytes. Hemopoiesis eventually declines, with no evidence for the generation of Friend tumor cells. When erythropoiesis is induced in the long-term cultures by addition of anemic mouse serum before infection by polycythemia-inducing Friend virus, the generation of erythropoietin-independent CFU-E and erythrocyte formation is followed by the sustained production (greater than 40 wk) of primitive erythroid cells with low spontaneous levels (less than 5%) of hemoglobinization. Although these cells will produce spleen colonies in irradiated mice and can be cloned in soft-gel media, they do not produce autonomous, permanently growing cell lines in vitro, i.e., they retain a dependency upon the marrow-adherent layer for their continued growth. However, following a further passage on a "virgin" marrow environment, permanent cell lines can be established that are able to grow independently of environmental influences. Thus, this system is the first description of a complete in vitro system for the reproducible production and isolation of Friend virus-induced erythroid cell lines.

Sleep-disordered breathing in a sample of 495 children in Southern Italy.

AIM: Our objective was to investigate the occurrence of sleep-related breathing disturbances in a large cohort of school-aged children in Southern Italy, and to evaluate the association with anthropometric data and clinical findings of oropharynx and nasal airways. STUDY DESIGN: A two-phase cross-sectional study was conducted with children from schools in Turi, Italy. MATERIALS AND METHODS: A screening phase aimed to identify symptomatic children and clinical data from a cohort of 495 children by a self-administered questionnaire, and an instrumental phase for the definition of sleep-related disorders and clinical analysis of oral status were performed. According to the answers, children were classified into 3 groups: habitual snorers, occasional snorers, and non-snorers. All habitual snoring children underwent a polysomnographic home evaluation, and those with oxygen desaturation index (ODI) > 2 were considered for nocturnal polygraphic monitoring (NPM). Children with apnoea/ hypopnea index (AHI) > 3 received a diagnosis of obstructive sleep apnoea syndrome (OSAS). Moreover, a complete oral examination was performed. RESULTS: A total of 436 questionnaires (response rate: 88.08%) were returned and scored (202 M, 234 F; Mean age ± Standard deviation: 6.2 ± 1.8); 18 children (4%) were identified as habitual snorers, 140 children (32%) were identified as occasional snorers, and 278 children (64%) were identified as non-snorers. The percentage of female children who were habitual snorers was higher than the percentage of male children (4.7% vs 3.6%). Habitual snorers had significantly more nighttime symptoms. OSAS was diagnosed in 2 children by NPM. A statistically significant association between snoring, cross-bite, open-bite and increased over-jet was found. CONCLUSION: Habitual snoring and OSAS are significant problems for children and may be associated with diurnal symptoms. The presence of malocclusion increases the likelihood of sleep-related breathing disturbances.

Loss of aromatase cytochrome P450 function as a risk factor for Parkinson's disease?

The final step in the physiological synthesis of 17beta estradiol (E(2)) is aromatization of precursor testosterone by a CYP19 gene product, cytochrome P450 estrogen aromatase in the C19 steroid metabolic pathway. Within the central nervous system (CNS) the presence, distribution, and activity of aromatase have been well characterized. Developmental stage and injury are known modulators of brain enzyme activity, where both neurons and glial cells reportedly have the capability to synthesize this key estrogenic enzyme. The gonadal steroid E(2) is a critical survival, neurotrophic and neuroprotective factor for dopaminergic neurons of the substantia nigra pars compacta (SNpc), the cells that degenerate in Parkinson's disease (PD). In previous studies we underlined a crucial role for the estrogenic status at the time of injury in dictating vulnerability to the parkinsonian neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Our ongoing studies address the contribution of brain aromatase and extragonadal E(2) as vulnerability factors for PD pathology in female brain, by exposing aromatase knockout (ArKO, -/-) female mice which are unable to synthesize estrogens to MPTP. Our initial results indicate that aromatase deficiency from early embryonic life significantly impairs the functional integrity of SNpc tyrosine hydroxylase-positive neurons and dopamine transporter innervation of the caudate-putamen in adulthood. In addition, ArKO females exhibited a far greater vulnerability to MPTP-induced nigrostriatal damage as compared to their Wt type gonadally intact and gonadectomized counterparts. Characterization of this novel implication of P450 aromatase as determining factor for PD vulnerability may unravel new avenues for the understanding and development of novel therapeutic approaches for Parkinson's disease.

Effects of Curcumin on Squamous Cell Carcinoma of Tongue: An In Vitro Study.

BACKGROUND: The Squamous Cell Carcinoma of the Tongue (TSCC) is the most frequent cancer of oral cavity often characterized by poor prognosis. Conventional therapies are not very efficient and often may cause serious side effects. In this context, introduction of natural substances as possible adjuvant in the treatment and prevention of cancer is becoming a relevant topic. In fact, curcumin has been used for decades in Chinese traditional medicine for its beneficial effects. Curcumin has anticancer properties in many tumors however, its action on the tongue carcinoma is not entirely clear and many other investigations are necessary. OBJECTIVE: Curcumin seems to be a good adjuvant in the treatment of head and neck tumors. However, these studies are generic and there are not many specific studies on TSCC, the most frequent and most aggressive cancer of the head-neck region. Our goal is to demonstrate its effectiveness also for TSCC. METHODS: In this study, we evaluated the effects of curcumin on TSCC cells using different concentrations (1, 5, 10, 20 and 50 µM) and 3 different treatment times (24, 48 and 72 hours). The inhibition of adhesion, proliferation, viability, migration and apoptosis was studied. RESULTS: IC50 value of curcumin is about 10 µM and there have been inhibitory effects even for treatments at low concentrations. Curcumin reduces migration and progression of TSCC cells and it promotes apoptosis and inhibits tumorigenesis. CONCLUSIONS: These results suggest the possible use of curcumin as an anti-cancer agent in TSCC. However, in vivo studies are needed to confirm these effects and overcome its low bioavailability.

Primary hyperoxaluria: Orthodontic management in a pediatric patient: A case report.

AIMS: The aim of this study is to report the case of the orthodontic treatment in a patient affected by primary hyperoxaluria type 1 and subjected to a combinate liver-kidney transplant. METHODS AND RESULTS: The 9-year patient was admitted to our department for the presence of facial dysmorphism. The patient was affected by primary hyperoxaluria type 1 and has undergone a combined liver-kidney transplantation. At the time of the visit, he was in treatment with immunosuppressive drugs and received a corticosteroid and an antibiotic therapy monthly. An intraoral and extraoral examination, as well as radiographic and model analysis, was performed in order to define an accurate diagnosis and a proper rehabilitation planning. An orthopedic-orthodontic treatment was performed and satisfactory final results obtained. A laser gingivectomy was also realized for eliminate the gengival hyperplasia probably induced by cyclosporine assumption. Both skeletal and dental relationships were improved by the treatment, reaching a good dental arches alignment. CONCLUSION: An early diagnosis, as well as a multidisciplinary approach, is very important in patients with rare diseases. An appropriate treatment allowed us to achieve acceptable results and improve the patient quality of life.

Estrogen, neuroinflammation and neuroprotection in Parkinson's disease: glia dictates resistance versus vulnerability to neurodegeneration.

Post-menopausal estrogen deficiency is recognized to play a pivotal role in the pathogenesis of a number of age-related diseases in women, such as osteoporosis, coronary heart disease and Alzheimer's disease. There are also sexual differences in the progression of diseases associated with the nigrostriatal dopaminergic system, such as Parkinson's disease, a chronic progressive degenerative disorder characterized by the selective degeneration of mesencephalic dopaminergic neurons in the substancia nigra pars compacta. The mechanism(s) responsible for dopaminergic neuron degeneration in Parkinson's disease are still unknown, but oxidative stress and neuroinflammation are believed to play a key role in nigrostriatal dopaminergic neuron demise. Estrogen neuroprotective effects have been widely reported in a number of neuronal cell systems including the nigrostriatal dopaminergic neurons, via both genomic and non-genomic effects, however, little is known on estrogen modulation of astrocyte and microglia function in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine model of Parkinson's disease. We here highlight estrogen modulation of glial neuroinflammatory reaction in the protection of mesencephalic dopaminergic neurons and emphasize the cardinal role of glia-neuron crosstalk in directing neuroprotection vs neurodegeneration. In particular, the specific role of astroglia and its pro-/anti-inflammatory mechanisms in estrogen neuroprotection are presented. This study shows that astrocyte and microglia response to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine injury vary according to the estrogenic status with direct consequences for dopaminergic neuron survival, recovery and repair. These findings provide a new insight into the protective action of estrogen that may possibly contribute to the development of novel therapeutic treatment strategies for Parkinson's disease.

GSK-3ß-induced Tau pathology drives hippocampal neuronal cell death in Huntington's disease: involvement of astrocyte-neuron interactions.

Glycogen synthase kinase-3ß (GSK-3ß) has emerged as a critical factor in several pathways involved in hippocampal neuronal maintenance and function. In Huntington's disease (HD), there are early hippocampal deficits both in patients and transgenic mouse models, which prompted us to investigate whether disease-specific changes in GSK-3ß expression may underlie these abnormalities. Thirty-three postmortem hippocampal samples from HD patients (neuropathological grades 2-4) and age- and sex-matched normal control cases were analyzed using real-time quantitative reverse transcription PCRs (qPCRs) and immunohistochemistry. In vitro and in vivo studies looking at hippocampal pathology and GSK-3ß were also undertaken in transgenic R6/2 and wild-type mice. We identified a disease and stage-dependent upregulation of GSK-3ß mRNA and protein levels in the HD hippocampus, with the active isoform pGSK-3ß-Tyr(216) being strongly expressed in dentate gyrus (DG) neurons and astrocytes at a time when phosphorylation of Tau at the AT8 epitope was also present in these same neurons. This upregulation of pGSK-3ß-Tyr(216) was also found in the R6/2 hippocampus in vivo and linked to the increased vulnerability of primary hippocampal neurons in vitro. In addition, the increased expression of GSK-3ß in the astrocytes of R6/2 mice appeared to be the main driver of Tau phosphorylation and caspase3 activation-induced neuronal death, at least in part via an exacerbated production of major proinflammatory mediators. This stage-dependent overactivation of GSK-3ß in HD-affected hippocampal neurons and astrocytes therefore points to GSK-3ß as being a critical factor in the pathological development of this condition. As such, therapeutic targeting of this pathway may help ameliorate neuronal dysfunction in HD.

Multicyclic, dose-intensive chemotherapy supported by sequential reinfusion of hematopoietic progenitors in whole blood.

PURPOSE: To support multicyclic, dose-intensive chemotherapy, we assessed the effects of reinfusing hematopoietic progenitors collected at each cycle in leukapheresis product or whole blood. PATIENTS AND METHODS: Twenty-five patients with small-cell lung cancer (SCLC) were treated with six cycles of ifosfamide, carboplatin, and etoposide (ICE) with granulocyte colony-stimulating factor (G-CSF) 300 micrograms/d subcutaneously (SC) on days 4 to 15. Hematopoietic progenitors collected during each cycle were reinfused on day 3 of the next cycle. Cohort 1 (n = 6) was treated every 3 weeks, with leukapheresis after 2 weeks and cryopreservation of the leukapheresis product. Chemotherapy was given if the WBC count was > or = 3 x 10(9)/L and platelet count > or = 100 x 10(9)/L. Cohort 2 (n = 7) was treated every 2 weeks, with leukapheresis on day 1 of the next cycle and storage of the leukapheresis product at 4 degrees C. Cohort 3 (n = 12) was treated every 2 weeks, with 500 to 750 mL of blood drawn by venesection on day 1 of the next cycle and stored at 4 degrees C. In cohorts 2 and 3, chemotherapy was given if the WBC count was > or = 3 x 10(9)/L and platelet count > or = 30 x 10(9)/L. Blood and leukapheresis products were assayed for hematopoietic progenitors. RESULTS: ICE chemotherapy with G-CSF was effective in mobilizing blood progenitors (median, 120-fold). Long-term cultures showed no evidence of stem-cell depletion. The cytotoxic dose-intensity of standard every-4-weeks ICE is 100%. In the first three cycles, it was 134% (median) in cohort 1 and 200% in cohorts 2 and 3 (P < .0001). Toxicity and supportive care requirements were not increased. CONCLUSION: The dose-intensity of ICE chemotherapy can be doubled by reinfusing hematopoietic progenitors collected by leukapheresis or venesection and stored at 4 degrees C.

Clinical and in vitro effects of recombinant human erythropoietin in patients receiving intensive chemotherapy for small-cell lung cancer.

PURPOSE: Recombinant human erythropoietin (r-Hu-EPO) is known to be effective in untreated cancer patients. Here we assess the possibility that r-Hu-EPO may also prevent or reduce anemia in patients who receive cytotoxic chemotherapy. METHODS: Thirty-six patients with small-cell lung carcinoma (SCLC) were enrolled onto a three-arm, randomized trial to investigate the effect of r-Hu-EPO on hemoglobin (Hb) levels and RBC and platelet (Plt) transfusions during chemotherapy. Bone marrow progenitors were studied before and after treatment. Two groups of patients received r-Hu-EPO at a dose of either 150 IU/kg (group 150) or 300 IU/kg (group 300) three times per week for the duration of chemotherapy. A control group did not receive r-Hu-EPO (group O). A maximum of six cycles of a chemotherapy regimen that consisted of vincristine, ifosfamide, carboplatin, and etoposide (VICE) were given to all patients. Hematologic parameters were measured weekly, and RBC or Plt transfusions were given for Hb levels less than 9 g/dL and Plt counts less than 20 x 10(9)/L. RESULTS: Hb levels decreased in all patients, but onset of anemia was delayed in groups that received r-Hu-EPO (P = .002). A total of 116 U RBC were transfused in group 0, 54 in group 150, and 52 in group 300 (P = .017). In addition, there was a nonsignificant trend toward higher Plt counts and fewer Plt transfusions in patients who received r-Hu-EPO. CONCLUSION: r-Hu-EPO at a dose of either 150 or 300 IU/kg three times weekly delays the onset of anemia and reduces RBC transfusion requirements in patients who undergo intensive chemotherapy for SCLC. A possible effect of r-Hu-EPO on platelet numbers deserves further study.

Randomized comparison of progenitor-cell mobilization using chemotherapy, stem-cell factor, and filgrastim or chemotherapy plus filgrastim alone in patients with ovarian cancer.

PURPOSE: This was the first randomized study to investigate the efficacy of peripheral-blood progenitor cell (PBPC) mobilization using stem-cell factor (SCF) in combination with filgrastim (G-CSF) following chemotherapy compared with filgrastim alone following chemotherapy. PATIENTS AND METHODS: Forty-eight patients with ovarian cancer were treated with cyclophosphamide and randomized to receive filgrastim 5 microg/kg alone or filgrastim 5 microg/kg plus SCF. The dose of SCF was cohort-dependent (5, 10, 15, and 20 microg/kg), with 12 patients in each cohort, nine of whom received SCF plus filgrastim and the remaining three patients who received filgrastim alone. On recovery from the WBC nadir, patients underwent a single apheresis. RESULTS: SCF in combination with filgrastim following chemotherapy enhanced the mobilization of progenitor cells compared with that produced by filgrastim alone following chemotherapy. This enhancement was dose-dependent for colony-forming unit-granulocyte-macrophage (CFU-GM), burst-forming unit-erythrocyte (BFU-E), and CD34+ cells in both the peripheral blood and apheresis product. In the apheresis product, threefold to fivefold increases in median CD34+ and progenitor cell yields were obtained in patients treated with SCF 20 microg/kg plus filgrastim compared with yields obtained in patients treated with filgrastim alone. Peripheral blood values of CFU-GM, BFU-E, and CD34+ cells per milliliter remained above defined threshold levels longer with higher doses of SCF. The higher doses of SCF offer a greater window of opportunity in which to perform the apheresis to achieve high yields. CONCLUSION: SCF (15 or 20 microg/kg) in combination with filgrastim following chemotherapy is an effective way of increasing progenitor cell yields compared with filgrastim alone following chemotherapy.

Colony-stimulating factors in the clinic.

Recombinant purified human haemopoietic growth factors are available for clinical trials and some have been licensed for therapeutic use. Some haemopoietic lineages (erythroid, neutrophilic, monocyte-macrophagic) can be selectively stimulated in order to ameliorate the cytopenias that follow cytotoxic treatment, or that characterize some haematological syndromes, and to stimulate mature cell function. Advances in the knowledge of receptor-ligand interactions and of transduction mechanisms, plus the production of synthetic or mutant molecules that may mimic, potentiate or antagonize the effects of the natural growth factors, should make novel therapeutic approaches possible.

Detection of hTERT protein by flow cytometry.

Telomerase is a telomere-specific DNA polymerase consisting of protein and RNA components, which is activated in germline cells and the majority of cancers and serves to counter the consequences of telomere shortening. The protein component, hTERT, is believed to be the catalytic subunit of human telomerase and its expression at the mRNA level correlates well with telomerase activity in vitro. Current techniques for assaying telomerase activity detect only the mean activity in a sample and are unable to isolate specific cell sub-populations. This report describes the development and validation of a cellular, immunofluorescence-based flow cytometry assay that allows detection of intranuclear hTERT while maintaining identifiable cell population characteristics. The assay was shown to be both sensitive to changes in telomerase expression and was semi-quantitative. In both cell line differentiation experiments and in primary cells, a good correlation existed between hTERT expression measured by flow cytometry and telomerase activity detected by the telomeric repeat amplification protocol (TRAP). The method developed offers a quick, simple and reproducible cellular-based assay for hTERT expression. This assay will provide a useful, new tool for future investigations, facilitating the analysis of hTERT expression in mixed cell populations.

NOD/SCID repopulating cells but not LTC-IC are enriched in human CD34+ cells expressing the CCR1 chemokine receptor.

Human haemopoietic stem and progenitor cells may be distinguished by the pattern of cell surface markers they display. The cells defined as 'stem' cells are heterogeneous and lack specific markers for their detection. However, they may be identified in in vitro assays such as the long-term culture initiating cell (LTC-IC) and in transplant assays involving immunosuppressed NOD/SCID mice. It is still not clear to what extent, if any, these cell populations overlap. The chemokine macrophage inflammatory protein-1alpha (MIP-1alpha) prolongs survival of LTC-IC in suspension cultures and we now show that in longterm bone marrow cultures (LTBMC) maintenance of haemopoiesis was significantly better from the CD34+ cells which possess MIP-1alpha receptors (P < 0.006). We examined one MIP-1alpha receptor, CCR1, which is present on CD34+ cells from haemopoietic tissues. In LTBMC the production of GM-CFC from CD34+CCR1- cells was significantly higher (P < 0.02) than that from CD34+CCR1+ cultures and the incidence of LTC-IC was 3- to 6-fold higher in the CD34+CCR1- cell fraction. In contrast, the cells responsible for high levels of engraftment in NOD/SCID mice were contained in the CD34+CCR1+ cell fraction. The CD34+CCR1+ cells engrafted to high levels in NOD/SCID and generated large numbers of progenitor cells. Therefore, we conclude that LTC-IC and SRC may be distinguished on the basis of expression of the chemokine receptor CCR1.

Recombinant human megakaryocyte growth and development factor (MGDF) increases the numbers of megakaryocyte progenitor cells to normal values in long-term bone marrow cultures of patients with AML in first remission.

The megakaryopoietic potential in the bone marrow (BM) of patients in first remission after treatment for acute myelogenous leukaemia (AML) was investigated using long-term bone marrow cultures (LTC) stimulated with megakaryocyte growth and development factor (MGDF). The baseline number of megakaryocyte colony-forming cells (Meg-CFC) was very low. However, there was a 10 to 100-fold increase of Meg-CFC in cultures treated with 10 ng/ml MGDF with mean numbers within the normal range for the first 4 weeks of culture with a 24-fold increase in their cumulative numbers. Similarly, a 12-fold increase in the numbers of megakaryocytes (MKs) was found by CD61 immunostaining. These effects were lost at the dose of 100 ng/ml. In contrast, the cumulative mean numbers of Meg-CFC in the control cultures from normal bone marrow (NBM) were not significantly different from those in cultures treated with 10 or 100 ng/ml MGDF. These results demonstrate that MGDF stimulates megakaryocytopoiesis in patients with AML in first remission, restoring the Meg-CFC compartment to normal values, a result with potential clinical implications for their treatment with autologous transplantation.

Characterisation of the differential response of normal and CML haemopoietic progenitor cells to macrophage inflammatory protein-1alpha.

The clonogenic cells of chronic myeloid leukaemia (CML), unlike normal haemopoietic colony forming cells (CFC), are resistant to the growth inhibitory effects of the chemokine, macrophage inflammatory protein-1alpha (MIP-1alpha). Here, we tested the hypothesis that MIP-1alpha protects normal, but not CML, CFC from the cytotoxic effects of the cell-cycle active drug cytosine arabinoside (Ara-C). Using a 24-h Ara-C protection assay we showed that MIP-1alpha confers protection to normal CFC but also sensitizes CML CFC to Ara-C. The differential MIP-1alpha responsiveness was not due to a down-regulation of MIP-1alpha receptors on CML CD34+ cells as flow cytometric analysis showed similar binding of a biotinylated MIP-1alpha molecule to normal and CML CD34+ cells. Flow cytometric analysis of the MIP-1alpha receptor subtype CCR-5 revealed comparable CCR-5 expression levels on normal and CML CD34+ cells. Furthermore, culture of CD34+ cells for 10 h in the presence of TNF-alpha resulted in an increased MIP-1alpha receptor expression on both normal and CML CD34+ cells. Our data suggest that the unresponsiveness of CML CFC to the growth inhibitory effect of MIP-1alpha is not caused by a lack of MIP-1alpha receptor or total uncoupling of the MIP-1alpha responsiveness but may be due to an intracellular signalling defect downstream of the receptors.

Macrophage inflammatory protein 1alpha attenuates the toxic effects of temozolomide in human bone marrow granulocyte-macrophage colony-forming cells.

Macrophage inflammatory protein 1alpha (MIP-1alpha) is a chemokine that may act principally by preventing hemopoietic cells from entering G1, thereby attenuating the cytotoxic effects of cell cycle-specific chemotherapeutic agents. Here we examine the effect of MIP-1alpha on the sensitivity of human granulocyte-macrophage hemopoietic progenitor cells (granulocyte-macrophage colony-forming cells; GM-CFCs) with the cytotoxic effects of antitumor agents that act mainly via alkylation at the O6 position of guanine in DNA. Mononuclear cell preparations from human bone marrow were used in an in vitro GM-CFC colony-forming assay. The GM-CFC survival from individual patients displayed a range of sensitivities to the methylating agent temozolomide [(Tz) 20-55% survival at 10 microg/ml Tz]. However, in all 16 cases, MIP-1alpha (50 ng/ml) protected against GM-CFC killing: survival in the presence of MIP-1alpha ranged from 65-97% at 10 microg/ml Tz, with GM-CFCs being 1.5-4.5-fold more resistant than control cells from the same patient. The highest levels of protection were seen in the GM-CFCs with the highest sensitivity in the absence of MIP-1alpha. Similar degrees of protection were seen for the methylating agent streptozotocin, but no protection was detected for the chloroethylating agents carmustine or mitozolomide in the samples for which there was protection against the toxic effects of Tz. Whereas the mechanism of this effect remains to be established, the results may have potential immediate clinical application in the attenuation of hematological toxicity after administration of methylating antitumor agents.