Relative rates of cancers and deaths in Australian communities with PFAS environmental contamination associated with firefighting foams: A cohort study using linked data.

BACKGROUND: Per- and polyfluoroalkyl substances (PFAS) are environmental contaminants that are potentially harmful to health. We examined if rates of selected cancers and causes of deaths were elevated in three Australian communities with local environmental contamination caused by firefighting foams containing PFAS. The affected Australian communities were Katherine in Northern Territory, Oakey in Queensland and Williamtown in New South Wales. METHODS: All residents identified in the Medicare Enrolment File (1983-2019)-a consumer directory for Australia's universal healthcare-who ever lived in an exposure area (Katherine, Oakey and Williamtown), and a sample of those who ever lived in selected comparison areas, were linked to the Australian Cancer Database (1982-2017) and National Death Index (1980-2019). We estimated standardised incidence ratios (SIRs) for 23 cancer outcomes, four causes of death and three control outcomes, adjusting for sex, age and calendar time of diagnosis. FINDINGS: We observed higher rates of prostate cancer (SIR=1·76, 95 % confidence interval (CI) 1·36-2·24) in Katherine; laryngeal cancer (SIR=2·71, 95 % CI 1·30-4·98), kidney cancer (SIR=1·82, 95 % CI 1·04-2·96) and coronary heart disease (CHD) mortality (SIR=1·81, 95 % CI 1·46-2·33) in Oakey; and lung cancer (SIR=1·83, 95 % CI 1·39-2·38) and CHD mortality (SIR=1·22, 95 % CI 1·01-1·47) in Williamtown. We also saw elevated SIRs for control outcomes. SIRs for all other outcomes and overall cancer were similar across exposure and comparison areas. INTERPRETATION: There was limited evidence to support an association between living in a PFAS exposure area and risks of cancers or cause-specific deaths.

Mini-review of waste sector greenhouse gas and short-lived climate pollutant emissions in Tyre Caza, Lebanon, using the Solid Waste Emissions Estimation Tool ('SWEET').

In 2020, International Solid Waste Association's (ISWA) Task Force on Closing Dumpsites completed a study of waste sector short-lived climate pollutants (SLCPs) and other greenhouse gas (GHG) emissions in Tyre Caza, Lebanon, using the Solid Waste Emissions Estimation Tool (SWEET). SWEET model runs used data on municipal solid waste (MSW) generation, collection, disposal, and diversion under existing and potential alternative management scenarios proposed in an Integrated Waste Management Plan (IWMP) for Tyre Caza. Waste sector emissions reductions exceeding 45% of baseline levels are achievable by 2030 if all dumpsites are closed and remediated, waste burning stopped, and a new sanitary landfill developed with 60% methane collection and combustion. Additional emissions reduction accrues from implementing the IWMP and upgrading existing waste treatment facilities to increase waste diversion rates from current levels (22% including informal sector recycling) to 40%. Estimates of all of Lebanon's waste sector emissions using SWEET were developed for this mini-review article using published data on the amounts of MSW collected, disposed, and diverted, with adjustments to account for indirect GHG reductions from composting and anaerobic digestion (AD). A 50% reduction in emissions from baseline levels can be achieved by 2034, if by 2025 diversion of collected wastes to recycling, composting, and AD facilities is increased from 14% to 28%, and all residual MSW is disposed in sanitary landfills with 65% methane recovery.

IglC and PdpA are important for promoting Francisella invasion and intracellular growth in epithelial cells.

The highly infectious bacteria, Francisella tularensis, colonize a variety of organs and replicate within both phagocytic as well as non-phagocytic cells, to cause the disease tularemia. These microbes contain a conserved cluster of important virulence genes referred to as the Francisella Pathogenicity Island (FPI). Two of the most characterized FPI genes, iglC and pdpA, play a central role in bacterial survival and proliferation within phagocytes, but do not influence bacterial internalization. Yet, their involvement in non-phagocytic epithelial cell infections remains unexplored. To examine the functions of IglC and PdpA on bacterial invasion and replication during epithelial cell infections, we infected liver and lung epithelial cells with F. novicida and F. tularensis 'Type B' Live Vaccine Strain (LVS) deletion mutants (ΔiglC and ΔpdpA) as well as their respective gene complements. We found that deletion of either gene significantly reduced their ability to invade and replicate in epithelial cells. Gene complementation of iglC and pdpA partially rescued bacterial invasion and intracellular growth. Additionally, substantial LAMP1-association with both deletion mutants was observed up to 12 h suggesting that the absence of IglC and PdpA caused deficiencies in their ability to dissociate from LAMP1-positive Francisella Containing Vacuoles (FCVs). This work provides the first evidence that IglC and PdpA are important pathogenic factors for invasion and intracellular growth of Francisella in epithelial cells, and further highlights the discrete mechanisms involved in Francisella infections between phagocytic and non-phagocytic cells.

Outcomes of non-surgical periodontal treatment by dental hygienists in training: impact of site- and patient-level factors.

OBJECTIVES: To investigate the site- and patient-level factors that impact on the response to non-surgical periodontal therapy in patients with chronic periodontitis. METHODS: A retrospective evaluation of clinical outcomes following non-surgical periodontal therapy delivered by dental hygienists in training was undertaken. Case notes from 195 patients with chronic periodontitis were reviewed and clinical data pre- and post-treatment abstracted. Patients were categorized as 'responders' or 'non-responders' according to defined outcome criteria, and the relationship between clinical and demographic variables and treatment outcomes was assessed. RESULTS: Overall, there was a good response to the periodontal treatment. At deep sites (those with pretreatment probing depth ≥5 mm), the mean probing depth reduction was 1.6 ± 0.9 mm. Seventy-one (36%) patients were classified as non-responders (indicating that at least 30% of their deep sites did not improve by at least 2 mm following treatment). The non-responding group contained a significantly greater proportion of smokers (28%) than the responding group (16%). Plaque scores did not differ significantly between responders or non-responders either pre- or post-treatment. Regression analyses indicated that smoking status (odds ratio, OR: 2.04), mean pretreatment probing depth (OR: 1.49) and percentage of deep sites ≥5 mm at pretreatment (OR: 1.02) were significantly associated with response to treatment. CONCLUSION: This study supports the benefits of non-surgical therapy in the treatment of chronic periodontitis by dental hygienists in training. Better responses to treatment tend to be observed in non-smokers and in those with less advanced periodontitis at baseline.

Examination of in vitro epithelial cell lines as models for Francisella tularensis non-phagocytic infections.

Francisella tularensis (F. tularensis), the causative agent of tularemia, has long been known to invade and occupy non-phagocytic epithelial cells. Many epithelial cell infection models have been developed to study this process; however, due to the lack of consensus on infection methods and precise experimental procedures to evaluate invasion and replication, selection of appropriate models to use based on the literature is challenging. To evaluate in vitro non-phagocytic cell infection models, we chose 8 epithelial cultured cell lines from published models to infect with F. tularensis subspecies novicida (F. novicida) and compared the results to a recently developed model that used the mouse hepatocyte BNL CL.2 cell line. We utilized classical gentamicin-based invasion assays to determine total intracellular bacterial loads and employed microscopic examination with staining techniques that distinguished between intracellular and extracellular bacteria to provide an accurate assessment of the proportion of invaded host cells and the degree of bacterial replication. We found that COS-7 cells exhibited the greatest invasion rates; CMT-93 cells contained the largest intracellular bacterial loads; ad HEK-293s were capable of invasion and replication rates at high levels, but required shorter infection incubation times. Although COS-7, CMT-93 and HEK-293 cell lines may be suited to study certain aspects of invasion or replication, we found that BNL CL.2 cells appeared the most appropriate to study the overall pathogenesis of F. novicida when examined in toto.

Association of common genetic variants with breast cancer risk and clinicopathological characteristics in a Chinese population.

Genome-wide association studies (GWAS) have identified various genetic susceptibility loci for breast cancer based mainly on European-ancestry populations. Differing linkage disequilibrium patterns exist between European and Asian populations, and thus GWAS-identified single nucleotide polymorphisms (SNPs) in one population may not be of significance in another population. In order to explore the role of breast cancer susceptibility variants in a Chinese population of Southern Chinese descent, we analyzed 22 SNPs for 1,191 breast cancer cases and 1,534 female controls. Associations between the SNPs and clinicopathological features were also investigated. In addition, we evaluated the combined effects of associated SNPs by constructing risk models. Eight SNPs were associated with an elevated breast cancer risk. Rs2046210/6q25.1 increased breast cancer risk via an additive model [per-allele odds ratio (OR) = 1.43, 95 % confidence interval (CI) = 1.26-1.62], and was associated with estrogen receptor (ER)-positive (per-allele OR = 1.39, 95 % CI = 1.20-1.61) and ER-negative (per-allele OR = 1.55, 95 % CI = 1.28-1.89) disease. Rs2046210 was also associated with stage 1, stage 2, and stage 3 disease, with per-allele ORs of 1.38 (1.14-1.68), 1.48 (1.25-1.74), and 1.58 (1.28-1.94), respectively. Four SNPs mapped to 10q26.13/FGFR2 were associated with increased breast cancer risk via an additive model with per-allelic risks (95 % CI) of 1.26 (1.12-1.43) at rs1219648, 1.22 (1.07-1.38) at rs2981582, 1.21 (1.07-1.36) at rs2981579, and 1.18 (1.04-1.35) at rs11200014. Variants of rs7696175/TLR1, TLR6, rs13281615/8q24, and rs16886165/MAP3K1 were also associated with increased breast cancer risk, with per-allele ORs (95 % CI) of 1.16 (1.00-1.34), 1.15 (1.02-1.29), and 1.15 (1.01-1.29), respectively. Five SNPs associated with breast cancer risk predominantly among ER-positive tumors (rs2981582/FGFR2, rs4415084/MRPS30, rs1219648/FGFR2, rs2981579/FGFR2, and rs11200014/FGFR2). Among our Chinese population, the risk of developing breast cancer increased by 90 % for those with a combination of 6 or more risk alleles, compared to patients with ≤3 risk alleles.

Urogynaecological problems in pregnancy.

The majority of urogynaecological problems can manifest during pregnancy or as a direct result of pregnancy and delivery. Those most commonly occurring during pregnancy are urinary tract infection, filling and voiding disorders, urinary incontinence, pelvic organ prolapse and faecal incontinence. The development of these may be as a result of physiological changes that occur in pregnancy or as a result of previous pregnancies. There may also be urogynaecological sequelae that occur as a result of trauma sustained during delivery. These include perineal and anal sphincter trauma, bladder or ureteric injuries during caesarean section or operative deliveries, and the development of vesico-vaginal or recto-vaginal fistulae.

The influence of ATP-binding cassette sub-family B member -1 (ABCB1) genetic polymorphisms on acute and chronic pain after intrathecal morphine for caesarean section: a prospective cohort study.

BACKGROUND: Polymorphisms of the ATP-binding cassette sub-family B member -1 (ABCB1) gene that codes for P-glycoprotein could influence the efflux of morphine from the central nervous system affecting its analgesic action. We investigated the effect of ABCB1 gene polymorphisms on analgesia and the development of persistent pain in post caesarean patients. METHODS: Women of Chinese descent who received spinal anaesthesia with intrathecal morphine for elective caesarean section were recruited. They were given intravenous morphine via a patient-controlled analgesia pump for postoperative analgesia. Blood samples were collected and analysed for the presence of C1236T, G2677T/A and C3435T single nucleotide polymorphisms of the ABCB1 gene. We primarily investigated the association between ABCB1 polymorphisms and the effect of morphine. In a postpartum phone survey of the subjects six months after surgery, the occurrence of persistent abdominal wound scar pain was established. RESULTS: We found no significant statistical difference in total morphine consumption, pain scores and side effects among the various genotypes. For C3435T polymorphism, there was a trend towards the association of the T allele and persistent pain for three months after surgery but this did not reach statistical significance (P=0.07). The TT genotype had the longest mean survival time of wound pain in comparison with CT and CC genotypes (P=0.004 and P=0.014, respectively). CONCLUSION: Polymorphisms of ABCB1 were not associated with differences in morphine use in the first 24h after surgery. Women with the T allele of C3435T polymorphism showed a trend towards a higher risk of developing persistent postoperative pain.

Differential fadE28 expression associated with phenotypic virulence of Mycobacterium tuberculosis.

Ability to persist in human macrophages is central to the virulence of Mycobacterium tuberculosis and is not invariable among various strains. Differential gene expression that is associated with phenotypic virulence may provide additional information of virulent genes involved in the pathogenesis of M. tuberculosis, which is not fully elucidated. Three hypervirulent strains of M. tuberculosis isolated from patients suffering with tuberculous meningitis were shown to grow more rapidly inside human macrophages in a previous study. In the current investigation, expression of 7 mycobacterial genes (fadE28, mce1A, mymA, acr, sigA, sugC, and Rv3723) of these strains during ex vivo macrophage challenge and in vitro acid shock was quantified by real-time PCR. Using rrs gene as a normalisation gene, fadE28 gene exhibited differential gene expression that is associated with phenotypic virulence, whereas the other 6 genes showed indistinguishable expression patterns. Up-regulation of fadE28 gene in the hypervirulent strains may account for virulence by increasing the efficiency of beta-oxidation, which is important for the persistence in macrophages as M. tuberculosis uses fatty acids preferably inside phagosome of macrophages. The fadE28 gene, together with its adjacent genes may also be critical in the process of lipid modification that could facilitate parasitism in human macrophages.

Molecular characterization of clinical isolates of Mycobacterium tuberculosis and their association with phenotypic virulence in human macrophages.

Among 125 clinical isolates of Mycobacterium tuberculosis collected in Hong Kong and Shanghai, China, between 2002 and 2004, IS6110 typing revealed that 71 strains (57%) belonged to the Beijing family. The intracellular growth of the strains in human peripheral blood monocyte-derived macrophages was measured ex vivo on days 0, 3, 6, and 10. Among all tested strains, three hypervirulent strains showed significant increases in intracellular growth after 10 days of incubation. With an initial bacterial load of 10(4) CFU, most of the clinical isolates and H37Ra (an avirulent strain) exhibited no intracellular survival on day 10, while the three hypervirulent strains together with H37Rv (a virulent strain) showed on average a two- to fourfold rise in CFU count. These three hypervirulent strains belonging to a non-Beijing family were isolated from patients suffering from tuberculosis meningitis. Cytokines secreted by gamma interferon-activated macrophages were measured daily after challenge with selected strains of M. tuberculosis. The levels of tumor necrosis factor alpha were elevated after 24 h of infection among all strains, but the levels were significantly lower among the three hypervirulent strains, whereas interleukin 10 (IL-10) and IL-12 were not detected. Results were concordant with the differential expression of the corresponding cytokine genes in activated macrophages, as monitored by real-time PCR. Our findings highlighted that these three hypervirulent strains may possess an innate mechanism for escaping host immunity, which accounts for their characteristic virulence in patients presenting with a more severe form of disease.

Testicular and paratesticular pathology in infants and children: the histopathological experience of a tertiary paediatric unit over a 17 year period.

To examine the pathological features of paediatric testicular and paratesticular lesions from a tertiary referral centre and describe their relative pathological frequency, highlighting relevant epidemiological and histopathological findings. A search was made of a computerised histopathology database covering the period from 1988 to 2004 inclusive to identify cases of testicular and paratesticular pathologies, and the clinical and histopathological features reviewed. Five hundred and fifty-one appropriate specimens underwent histological examination during the period. Three hundred and eleven (56%) presented with an impalpable testis with or without intersex disorder and 121 (22%) with a testicular/paratesticular mass. While metastatic leukaemic testicular involvement (N = 47) was the commonest tumour identified in this preselected series, at a peak of 8 years, primary testicular tumours such as yolk sac and teratoma were most commonly identified in infancy. Of 109 (20%) presenting with an acutely painful scrotum, the largest group (47%) represented torsion of the appendix testis. The vast majority of pathological samples arose from children less than 4 years of age in accordance with the predominance of cryptorchidism, 'vanished' testis, neonatal torsion and testicular tumours in this age group. The findings of this study demonstrate the spectrum of testicular pathology in childhood. Neoplasms represented >20% of the pathology, but the largest clinical group of pathological specimens in this patient population is associated with clinically impalpable or the palpably abnormal testis.

Risk of germ cell malignancy in children with XY intersex versus isolated cryptorchidism by immunohistochemistry.

The risk of subsequent development of testicular germ cell neoplasia is related to presence of underlying developmental defects such as cryptorchidism, in which the risk is around 0.5%, and XY intersex with abdominal testes, in which the risk may be as high as 20-25%. We examined the hypothesis that the increased risk of germ cell malignancy in intersex testes with Y chromosome was a direct consequence of an abnormal increase in number of PLAP/CD117+ immature germ cells into postnatal life. Archival cases of uncomplicated cryptorchidism (CO) and XY intersex (INT) were identified and anonymized, and a subgroup of aged-matched cases had sections immunostained with placental alkaline phosphatase (PLAP) and CD117. From a total of 89 intersex and 105 cryptorchid cases identified, a power calculation to detect a 20% difference in expression between groups (alpha = 0.05, power = 80%) determined that 18 intersex and 36 cryptorchid cases were required. Thus, 58 cases were examined, median age 3 (range birth-11) years, including 39 CO and 19 INT. The prevalence of any PLAP+ germ cells was 2/39 (5.1%) versus 3/19 (15.7%), respectively. (Z = 1.4, p = 0.17). In contrast, 94% of cases showed presence of any CD117+ germ cells, but the frequency of CD117+ cells was not significantly different between groups (t = 0.56, p = 0.58). CD117 and PLAP identify different populations of germ cells in pediatric testes. The extent of increased risk of malignancy in XY INT is not simply related to increased numbers of immature PLAP+/CD117+ germ cells present; additional factors play a pathogenic role.

Histopathological features of testicular regression syndrome: relation to patient age and implications for management.

Testicular regression syndrome (TRS) represents a congenital condition in which no normal testicular tissue can be identified following exploration for a clinically impalpable testis. A spectrum of pathological findings may be present but there is little literature systematically examining these features. We searched a pediatric histopathology database to identify cases of TRS, and the histopathological findings were reviewed and pooled with those of all previously published smaller series. A total of 117 cases were identified during the period (1989-2004), median age 2 (range birth-12) years. In 52 (44%) a nodule was identified macroscopically, median maximum diameter 0.5 (range 0.1-2.0) cm. Microscopic hemosiderin-laden macrophages were present in 85 (73%), dystrophic calcification in 52 (44%), residual testicular tubules in 12 (10%), vas deferens in 71 (61%), and epididymal tissue in 39 (33%). The prevalence of hemosiderin laden macrophages and dystrophic calcification were significantly greater in cases < or =3 years (84% versus 64% and 55% versus 32%, respectively). But there was no significant difference in the frequency of other findings between the younger and older age groups; in particular, the presence of residual testicular tubules was similar (7% versus 13%, respectively). Furthermore, there was no significant correlation between identification of a macroscopically distinct nodule and presence of residual tubular structures, tubules being identified in 6 of the 65 cases in which no clearly identifiable nodule was seen macroscopically. The presence of hemosiderin-laden macrophages and foci of dystrophic calcification showed a positive association. TRS is associated with specific histopathological features, the findings being consistent with changes secondary to intrauterine testicular torsion. Residual testicular tubules are found in 10% of cases regardless of the presence or absence of a macroscopically identifiable nodule.

Management of hypertension by private doctors in Hong Kong.

OBJECTIVE: To investigate the management of hypertension by private doctors in Hong Kong. DESIGN: Self-administered questionnaire survey. SETTING: Hong Kong. PARTICIPANTS: Private doctors from all districts in Hong Kong selected by simple random sampling from the website of "The Hong Kong Doctors Homepage" from March to June 2005. MAIN OUTCOME MEASURES: Practice of blood pressure measurement and the treatment prescribed to hypertensive patients. RESULTS: A total of 225 (46%) completed questionnaires were analysed. Only 24.4% of the respondents measured blood pressure in all new patients aged above 18 years. A total of 28.0% of doctors reported that hypertensive status was unknown in over 30% of their patients prior to their first clinic visit when it was consequently diagnosed. Calcium channel blockers (31%), angiotensin-converting enzyme inhibitors (28.5%), diuretics (27.5%), and beta-blockers (21.2%) were the most commonly prescribed antihypertensive medication. Drug efficacy was the reason cited by more than half (56.9%) of doctors for selecting a given drug. Public education about hypertension was considered insufficient by 66.2% of doctors and 32% believed that self-medication would have a very significant effect on drug compliance. CONCLUSIONS: In private clinics, blood pressure measurement should become a routine procedure. There is a need to raise public awareness of hypertension.

SMN1 deletions among singaporean patients with spinal muscular atrophy.

INTRODUCTION: Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder characterised by degeneration of spinal cord anterior horn cells, leading to muscular atrophy. It is the second most frequent autosomal recessive disease among Caucasian populations with a prevalence of between 1 in 6000 and 1 in 10,000 live births, and a carrier frequency of about 1 in 50. The International SMA Consortium classification defines several types of SMA depending on the age of onset and clinical severity. In the past, the diagnosis of SMA was confirmed by muscle biopsy and, sometimes, electromyography. In 1990, SMA was linked to the 5q13 region of chromosome 5. In 1995, it was found that >95% of patients with SMA have homozygous deletions of exons 7 and 8 of the survival motor neurone 1 (SMN1) gene, one of the candidate genes identified within 5q13. The purpose of our study was to determine the frequency of SMN1 deletions in patients with known SMA and the impact of this on the diagnosis of SMA. MATERIALS AND METHODS: Molecular analysis was performed on stored DNA and case notes were reviewed retrospectively. RESULTS: Twenty-two (91.7%) out of 24 patients with all types of SMA were homozygously deleted for exons 7 and/or 8 of SMN1. We also report our experience with prenatal diagnosis of SMA. CONCLUSIONS: Molecular studies can replace conventional investigations for SMA and have made the option of prenatal diagnosis possible for couples at risk.

Immediate provisional for single-tooth implant replacement with Brånemark system: preliminary report.

BACKGROUND: The success of osseointegrated implants ad modum Brånemark for single-tooth restorations is documented. Future developments should aim at improving the benefits to patients by decreasing treatment time, minimizing surgical stages, and maximizing esthetic outcomes. Using knowledge from studies of immediate implant placement, one-stage, immediate loading protocols, the authors developed the immediate provisional. PURPOSE: The purpose of this study was to develop a protocol to provide an immediate solution for restoring a single missing tooth in the esthetic zone. The protocol should be simple, predictable, cost effective, and allow the use of other techniques to improve esthetic outcome. MATERIALS AND METHOD: This prospective clinical study included 24 patients treated from August 1999 to October 2000. Single-tooth implant replacement was done according to immediate provisional protocol. Thirteen of the 24 patients had immediate implant placement after tooth extraction. All implants were placed in the esthetic zone. During surgery, emphasis was placed on obtaining primary stability by achieving bicortical anchorage and maximum insertion torque of at least 40 Ncm. CeraOne (Nobel Biocare) abutments were used, and provisional crowns were fabricated immediately before wound closure. The occlusion was protected by adjacent teeth. RESULTS: Within the follow-up period of between 1 month and 15 months, all fixtures in the 24 patients were stable. Crestal bone loss greater than one thread-width was not detected. The esthetic result was considered satisfactory by all patients. CONCLUSIONS: The implant placement and restoration protocol used in this study showed promising initial results for both the immediate implant and healed extraction site groups. The desirable goals of patient satisfaction, excellent esthetic outcomes, and no increase in treatment cost were achieved in this protocol. Further studies to elucidate the potential of the immediate provisional protocol are justified.

Changes of CD14 and CD1a expression in response to IL-4 and granulocyte-macrophage colony-stimulating factor are different in cord blood and adult blood monocytes.

Neonates are relatively immature in their immune response; thus, to further clarify the differences of monocyte function and differentiation between neonates and adults, we investigated their CD14(+)CD4(+) and CD14(+)CD16(+) monocyte subpopulations, production of IL-1beta and tumor necrosis factor-alpha induced by lipopolysaccharide, and their CD14 and CD1a phenotypic changes in response to IL-4 and granulocyte-macrophage colony-stimulating factor. Our results showed that 1) the expression of CD14 in cord blood monocytes was significantly lower than that in adult peripheral blood monocytes; 2) both the percentages of CD14(+)CD4(+) cells and CD14(+)CD16(+) cells among CD14(+) monocytes were also significantly lower in cord blood; 3) after stimulation by lipopolysaccharide for 72 h, production of both IL-1beta and tumor necrosis factor-alpha was lower in cord blood than that in adult peripheral blood; and 4) in response to IL-4 or GM-CSF, the phenotype development of CD14 and CD1a in cord blood and adult peripheral blood was different. Down-regulation of CD14 expression in response to IL-4 and GM-CSF was slower in cord blood monocytes than that in adult peripheral blood monocytes. After 9 d of culture in the presence of IL-4 and GM-CSF, the percentage of CD1a(+) monocytes was significantly more increased in cord blood than that in adult peripheral blood. The reduced expression of CD14 and other mature phenotype markers such as CD16 and CD4 as well as the reduced IL-1beta and tumor necrosis factor-alpha production may contribute to the impaired immune response of neonates. Slower down-regulation of CD14 by IL-4 and GM-CSF suggests that differential properties of cord blood monocytes in response to cellular stress signals take a longer time than those of adult peripheral blood monocytes.

Decreased yield, phenotypic expression and function of immature monocyte-derived dendritic cells in cord blood.

Dendritic cells are critical for the induction of both primary immune responses and immunological tolerance, as well as for the regulation of T-helper 1 (Th1) and 2 (Th2) immune responses. As neonates are notably deficient in Th1 response and cord blood transplantation is noted to result in less graft-versus-host disease (GvHD), we compared the phenotypic and functional characteristics of monocyte-derived dendritic cells (DCs) that favour Th1 development from cord blood and adult peripheral blood to understand the underlying mechanisms of these observations. Our results showed that: (1) after culture for 7 d with interleukin (IL)-4 and granulocyte--macrophage colony-stimulating factor (GM-CSF), cord blood monocytes generated less CD1a(+) cells than adult peripheral blood monocytes, and the CD1a+ cell percentage decreased thereafter; (2) compared with adult blood DCs, cord blood DCs had reduced intensity of expression of CD1a and MHC class II molecules, but the expression levels of CD11c and CD86 were similar; (3) the endocytotic ability of cord blood DCs was reduced compared with adult blood DCs, and this function was related to reduced mannose receptor (MR)-positive cells; (4) furthermore, the ability of cord blood DCs to stimulate CD3(+) T cells in an allogeneic mixed lymphocyte reaction was significantly lower than that of adult blood DCs. These results suggested that the dysfunction of cord blood monocytes in differentiating into professional DCs will affect the activation of naive T cells, especially Th1 development, and may be related to the susceptibility to different infections in the neonates, as well as the lower incidence of GvHD in cord blood transplantation.

Validation and development of quantitative flow cytometry-based fluorescence in situ hybridization for intercenter comparison of telomere length measurement.

BACKGROUND: Telomeres are highly conserved repeats at the ends of chromosomes that maintain chromosome stability and reflect the replicative potential of cells. Telomere length can be determined by Southern blot hybridization or quantitative fluorescence in situ hybridization (Q-FISH). Recently, two flow cytometry-based (Flow) FISH protocols have been published. METHODS: We compared the telomere length measured by Southern blotting and Flow FISH using standard beads to calibrate and quantify the fluorescence intensity. RESULTS: The telomeric fluorescence of cord blood and peripheral blood mononuclear cells was similar to that reported by other studies. There was a linear relationship between the telomeric fluorescence determined by Flow FISH and the telomere fragment size determined by Southern blotting (r = 0.89; P < 0.001). CONCLUSION: It is important to set up a center-specific curve and select appropriate cell lines for reference. This Q-Flow FISH protocol will facilitate the measurement of telomere length and allow more meaningful comparison of data (in standard fluorescence units or fragment size) between institutes.