Dental follicle progenitor cell heterogeneity in the developing mouse periodontium

As a developmental precursor for diverse periodontal tissues, the dental follicle (DF) harbors great promise for periodontal tissue regeneration. However, development of optimal therapy awaits the answer to a key question that impinges on many issues in development-Do adult progenitor tissues form a homogeneous cell population that differentiates into target tissues when they arrive at the site, or they contain heterogeneous cell populations that are committed to specific fates? To address the homogeneity/heterogeneity question, we analyzed differentiation pathways and markers in several cloned DF cell lines. Our studies revealed that each of our cloned DF lines featured remarkably unique characteristics, indicative of a separate and distinct lineage. One line, DF1, was high in proliferative activity but did not display any mineralization behavior, suggesting that it might be related to a periodontal ligament-type lineage. DF2 was similar to DF1, but featured remarkably high alkaline phosphatase activity indicative of a highly undifferentiated state. DF3 matched the mineralization characteristics of a same stage alveolar bone line AB1 in terms of gene expression and von Kossa staining, indicating that DF3 might be of cementoblastic or alveolar bone osteoblastic lineage. To verify the multilineage potential of the DF for purposes of tissue engineering, a series of differentiation induction experiments was conducted. For identification purposes, characteristics of these heterogeneous follicular progenitor cells were compared with follicle components in tissue sections of the postnatal developing periodontium. The presence of heterogeneous cell populations in the DF mirrors individual developmental pathways in the formation of the dental integument. The profound cellular heterogeneity of the DF as an adult progenitor for tissue regeneration also suggests that heterogeneous cellular constituents might play as much of a role in tissue regeneration as the inducible characteristics of individual lineages might do.     

Germline polymorphisms in patients with advanced nonsmall cell lung cancer receiving first-line platinum-gemcitabine chemotherapy: a prospective clinical study

BACKGROUND:

The authors assessed the impact of germline polymorphisms on clinical outcome in patients with advanced nonsmall cell lung cancer (NSCLC) who received platinum‐gemcitabine (PG) chemotherapy.

METHODS:

In total, 137 patients with stage IIIB/IV NSCLC were included who received first‐line PG chemotherapy (74% of patients received cisplatin, and 26% received carboplatin). Twenty‐three germline polymorphisms that were identified in peripheral blood samples were analyzed for progression‐free survival (PFS), treatment response, overall survival (OS), and toxicity.

RESULTS:

The median PFS was 5.8 months, the median OS was 10.2 months, and 44 patients (32%) had a partial treatment response. Carriers of the excision repair cross‐complementation group 1 (ERCC1) mutant thymine (T) allele had a lower treatment response rate (29% vs 52%; P = .02), shorter PFS (adjusted hazard ratio [HR], 1.60; P = .04), and shorter OS (adjusted HR, 1.54; P = .05) compared with carriers of the wild‐type cytosine/cytosine (CC) genotype. The xeroderma pigmentosum group A member 10 (XPD10) mutant adenine (A) allele (adjusted HR, 0.64; P = .04) and the x‐ray cross‐complementing group 1 (XRCC1) mutant guanine (G) allele (adjusted HR, 0.51; P = .02) also were independent predictors of OS. Carriers of the mutant adenosine triphosphate‐dependent DNA helicase Q1 (RECQ1) C allele or the mutant cytidine deaminase (CDA) C allele were more likely to experience severe leukocytopenia (26% vs 10% [P = .03] and 28% vs 11% [P = .02], respectively) compared with wild‐type genotype carriers. Patients who carried the homozygous mutant glutathione S‐transferase π 1(GSTP1) GG genotype were at considerable risk for severe platinum‐associated polyneuropathy (18% vs 3% in wild‐type vs heterozygous mutant patients, respectively; P = .01).

CONCLUSIONS:

To the authors' knowledge, this is the first prospective study to date in patients with advanced NSCLC describing predictive germline polymorphisms not only for the clinical activity of PG chemotherapy (ERCC1, XPD10) but also for its toxicity (GSTP1, RECQ1, CDA). Nonplatinum‐containing chemotherapy in carriers of the ERCC1 T allele or the XPD10 G allele should be studied prospectively. Cancer 2012;. © 2011 American Cancer Society.     

Promoter hypermethylation in male breast cancer: analysis by multiplex ligation-dependent probe amplification

ABSTRACT: INTRODUCTION: Epigenetic events are, along with genetic alteration, important in the development and progression of cancer. Promoter hypermethylation causes gene silencing and is thought to be an early event in carcinogenesis. The role of promoter hypermethylation in male breast cancer has not yet been studied. METHODS: In a group of 108 male breast cancers, the methylation status of 25 genes was studied using methylation-specific multiplex ligation-dependent probe amplification. Methylation of more than 15% was regarded indicative for promoter hypermethylation. Methylation status was correlated with clinicopathological features, with patients' outcome and with 28 female breast cancer cases. RESULTS: Promoter hypermethylation of the genes MSH6, WT1, PAX5, CDH13, GATA5 and PAX6 was seen in more than 50% of the cases, but was uncommon or absent in normal male breast tissue. High overall methylation status was correlated with high grade (P = 0.003) and was an independent predictor of poor survival (P = 0.048; hazard ratio 2.5). ESR1 and GSTP1 hypermethylation were associated with high mitotic count (P = 0.037 and P = 0.002, respectively) and high grade (both P = 0.001). No correlation with survival was seen for individual genes. Compared with female breast cancers (logistic regression), promoter hypermethylation was less common in a variety of genes, particularly ESR1 (P = 0.005), BRCA1 (P = 0.010) and BRCA2 (P < 0.001). The most frequently hypermethylated genes (MSH6, CDH13, PAX5, PAX6 and WT1) were similar for male and female breast cancer. CONCLUSION: Promoter hypermethylation is common in male breast cancer and high methylation status correlates with aggressive phenotype and poor survival. ESR1 and GSTP1 promoter hypermethylation seem to be involved in development and/or progression of high-grade male breast cancer. Although female and male breast cancer share a set of commonly methylated genes, many of the studied genes are less frequently methylated in male breast cancer, pointing towards possible differences between male and female breast carcinogenesis.     

Biomarker analysis in a phase III study of pemetrexed-carboplatin versus etoposide-carboplatin in chemonaive patients with extensive-stage small-cell lung cancer

BackgroundClinical results of a randomized phase III trial comparing pemetrexed–carboplatin (PC) with etoposide–carboplatin (EC) in chemonaive patients with extensive-stage disease small-cell lung cancer (ED-SCLC) resulted in trial closure for futility; biomarker analyses using immunohistochemistry (IHC) and single-nucleotide polymorphisms (SNPs) are described herein.Patients and MethodsThymidylate synthase (TS), excision repair cross complementing-1 (ERCC1), glycinamide ribonucleotide formyltransferase (GARFT), and folylpolyglutamate synthetase (FPGS) were investigated using IHC (n = 395). SNPs were genotyped for TS, FPGS, γ-glutamyl hydrolase (GGH), methylenetetrahydrofolate reductase (MTHFR), folate receptor-α FR-α, and solute carrier 19A1 (SLC19A1; n = 611).ResultsNone of the IHC biomarkers (folate pathway or ERCC1) were found to be predictive or prognostic in this setting. rs2838952 (adjacent to SLC19A1) had significant treatment-independent association with overall survival (OS; hazard ratio 0.590, P = 0.01). Nine GGH-associated SNPs interacted with rs3788205 (SLC19A1) for OS on the PC arm. rs12379987 (FPGS) interacted with treatment for OS (interaction P= 0.036).ConclusionPotential ERCC1 and folate pathway IHC biomarkers failed to predict outcome in either study arm in ED-SCLC. SNPs in regions including FPGS and SLC19A1 and interacting SNPs in GGH and SLC19A1 were associated with differences in OS; however, none of these SNPs predicted for greater survival with PC over EC.     

Renal Function in Glycogen Storage Disease Type I,Natural Course,and Renopreservative Effects of ACE Inhibition

Background and objectives: Renal failure is a major complication in glycogen storage disease type I (GSD I). We studied the natural course of renal function in GSD I patients. We studied differences between patients in optimal and nonoptimal metabolic control and possible renoprotective effects of angiotensin converting enzyme inhibition.Design, setting, participants, & measurements: Thirty-nine GSD I patients that visited our clinic were studied. GFR and effective renal plasma flow (ERPF) were measured by means of I¹²⁵ iothalamate and I¹³¹ hippuran clearance and corrected for body surface area. Microalbuminuria was defined as >2.5 mg albumin/mmol creatinine and proteinuria as >0.2 g protein per liter. Optimal metabolic control was present when blood glucoses were >3.5 mmol/L, urine lactate/creatinine ratios <0.06 mmol/mmol, triglycerides <6.0 mmol/L, and uric acid concentrations <450 μmol/L.Results: Quadratic regression analysis showed a biphasic pattern in the course of GFR and ERPF related to age. Microalbuminuria was observed significantly less frequently in the patients with optimal metabolic control compared with the patients with nonoptimal metabolic control. A significant decrease in GFR was observed after starting ACE inhibition.Conclusions: This study describes a biphasic pattern of the natural course of GFR and ERPF in GSD I patients, followed by the development of microalbuminuria and proteinuria. Optimal metabolic control has a renoprotective effect on the development of microalbuminuria and proteinuria in GSD I patients. Treatment with ACE inhibitors significantly decreases the GFR, especially in GSD I patients with glomerular hyperfiltration.Glycogen storage disease type I (GSD I) is an autosomal recessive inborn error of carbohydrate metabolism caused by a defect in the glucose-6-phosphatase (G6Pase) enzyme complex. It has an estimated incidence of 1 in 100,000 newborns. The G6Pase enzyme complex is needed in both glycogenolysis and gluconeogenesis to hydrolyze glucose-6-phosphate to glucose. The enzyme defect results in severe fasting hypoglycemia, hyperlactacidemia, hyperuricemia, and hyperlipidemia. Untreated patients have a protruding abdomen because of marked hepatomegaly (storage of glycogen and fat), short stature, truncal obesity, rounded doll face, wasted muscles, and bleeding tendency caused by impaired platelet function (1,2).The disease can be well controlled metabolically by use of a lifelong intensive dietary treatment, aimed at maintaining normoglycemia and suppressing secondary metabolic derangements. The diet consists of frequent meals during the day and gastric drip feeding or uncooked cornstarch at night. The life expectancy of patients with GSD I has considerably improved, although various complications occur with increasing age (3).In patients with GSD I, several renal complications have been reported. Enlargement of the kidneys is the earliest finding, caused by accumulation of glycogen in the kidneys and often contributing to the diagnosis of GSD I. Because of the hyperuricemia, uric acid nephrolithiasis and gout nephropathy can develop. These complications can, however, be prevented by improvement of the metabolic derangements with dietary treatment and by means of a xanthine oxidase inhibitor. Another cause of nephrolithiasis is the decreased urinary citrate excretion in combination with an increased urinary calcium excretion that occurs in GSD I patients. This condition can be treated with potassium citrate supplementation (4,5). Proximal tubular dysfunction has also been described in patients with GSD I. Hyperphosphaturia and loss of bicarbonate in urine can lead to renal tubular acidosis. These findings often resolve after starting intensive dietary treatment (6).Both glomerular hyperfiltration and persistent proteinuria have previously been reported (7–10). Renal biopsies performed in three GSD I patients with persistent proteinuria showed focal segmental glomerulosclerosis (11). These findings might suggest an etiology of glomerular hyperfiltration and proteinuria similar to diabetic nephropathy (12). With increasing age, the impairment of renal function in GSD I patients might become an important factor in quality of life and life expectancy.In patients with diabetes, randomized controlled trials have shown that treatment with angiotensin converting enzyme inhibitors (ACEi) significantly reduces the risk for onset of nephropathy, the risk for progression from microalbuminuria to microalbuminuria and increases the rate of regression to normoalbuminuria (13). Even in normotensive diabetic patients, these drugs reduce the intraglomerular pressure by specifically relaxing the efferent glomerular arterioles (14). This effect has not yet been proven in GSD I patients, although Melis et al. (15) described a decrease in GFR and a delay in progression from glomerular hyperfiltration to microalbuminuria in patients with GSD I.In this study, we analyzed the natural course of the GFR, effective renal plasma flow (ERPF), and the incidence of microalbuminuria and proteinuria in 39 patients with GSD I. We studied differences in GFR, microalbuminuria, and proteinuria between GSD I patients classified as having optimal or nonoptimal metabolic control. Finally, we analyzed the effects of ACEi on the severity of microalbuminuria and proteinuria.     

Neonatal porencephaly and adult stroke related to mutations in collagen IV A1

OBJECTIVE: The objective of this study was to describe leukoencephalopathy, lacunar infarcts, microbleeds and macrobleeds in the context of a collagen IV A1 mutation. METHODS: We examined a family with autosomal dominant porencephaly, in whom a defect in collagen IV A1 was detected recently. The patients underwent neurological, ophthalmological, and cardiological examinations and magnetic resonance imaging of the brain. Electron microscopy of a skin biopsy was performed. Extensive laboratory screening was performed for thrombophilia and increased bleeding tendency. RESULTS: The porencephaly was symptomatic in the infantile period in two patients, whereas it led to only minor neurological dysfunction in their affected mother. However, she experienced development of recurrent strokes in her 40s. In addition to the porencephaly, all patients had a leukoencephalopathy, which was most severe in the mother. Her magnetic resonance imaging results also showed lacunar infarcts, macrobleeds and a multitude of microbleeds. No other risk factors for recurrent stroke were found. Electron microscopy showed interruptions of the basement membrane of skin capillaries and inhomogeneous thickening of the basement membrane with pools of basement membrane fragments. INTERPRETATION: Leukoencephalopathy, ischemic infarcts, microbleeds, and macrobleeds are indicative of an underlying microangiopathy, of which the best-known causes are hypertension, cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, and cerebral amyloid angiopathy. Mutations in collagen IV A1, a major component of the vascular basement membrane, appear to be another risk factor.     

Coopdech管与双腔管在开胸术的应用及对术后声嘶喉痛的对比研究

目的 比较Coopdech支气管填塞管与双腔管在单肺通气应用的效果及对患者术后声嘶喉痛的影响。方法 择期全麻下行食管癌根治术患者100例,ASAⅠ～Ⅲ级,随机分成C组和D组（n=50）。C组采用单腔气管导管（ID7.5-8.0）复合Coopdech支气管填塞管,D组采用双腔支气管导管（35F-37F）。观察气管插管时间、插管尝试次数、术中导管移位次数、支纤镜使用次数,插管前后血流动力学变化,单肺通气时术侧肺塌陷及术野暴露情况,患者术后声嘶喉痛发生率及严重程度。结果 两组间相比插管时间C组比D组长,插管尝试次数、术中导管移位次数、支纤镜使用次数D组均比C组多,插管前后MAP、HR变化率D组均比C组高,单肺通气时肺塌陷D组比C组好,患者术后声嘶、喉痛总体发生率D组比C组高(P<0.05)。单肺时术野暴露情况及术后在PACU、1d、2d、3d、>3d时患者声嘶、喉痛严重程度组间比较差异无统计学意义(P>0.05)。结论 Coopdech支气管填塞管复合单腔管双肺阻隔效果确切,插管定位方便快捷,刺激小,可减少患者术后声嘶喉痛发生率,具有一定的临床应用前景。