Estimation of the genetic contribution of presenilin-1 and -2 mutations in a population-based study of presenile Alzheimer disease

Two closely related genes, the presenilins ( PS ), located at chromosomes 14q24.3 and 1q42.1, have been identified for autosomal dominant Alzheimer disease (AD) with onset age below 65 years (presenile AD). We performed a systematic mutation analysis of all coding and 5'-non-coding exons of PS -1 and PS -2 in a population-based epidemiological series of 101 unrelated familial and sporadic presenile AD cases. The familial cases included 10 patients of autosomal dominant AD families sampled for linkage analysis studies. In all patients mutations in the amyloid precursor protein gene ( APP ) had previously been excluded. Four different PS -1 missense mutations were identified in six familial cases, two of which where autosomal dominant cases. Three mutations resulted in onset ages above 55 years, with one segregating in an autosomal dominant family with mean onset age 64 years (range 50-78 years). One PS -2 mutation was identified in a sporadic case with onset age 62 years. Our mutation data provided estimates for PS -1 and PS -2 mutation frequencies in presenile AD of 6 and 1% respectively. When family history was accounted for mutation frequencies for PS -1 were 9% in familial cases and 18% in autosomal dominant cases. Further, polymorphisms were detected in the promoter and the 5'-non-coding region of PS -1 and in intronic and exonic sequences of PS -2 that will be useful in genetic association studies.      

The mouse Mid1 gene: implications for the pathogenesis of Opitz syndrome and the evolution of the mammalian pseudoautosomal region

We have recently reported isolation of the gene responsible for X- linked Opitz G/BBB syndrome, a defect of midline development. MID1 is located on the distal short arm of the human X chromosome (Xp22. 3) and encodes a novel member of the B box family of zinc finger proteins. We have now cloned the murine homolog of MID1 and performed preliminary expression studies during development. Mid1 expression in undifferentiated cells in the central nervous, gastrointestinal and urogenital systems suggests that abnormal cell proliferation may underlie the defect in midline development characteristic of Opitz syndrome. We have also found that Mid1 is located within the mouse pseudoautosomal region (PAR) in Mus musculus , while it seems to be X- specific in Mus spretus. Therefore, Mid1 is likely to be a recent acquisition of the M. musculus PAR. Genetic and FISH analyses also demonstrated a high frequency of unequal crossovers in the murine PAR, creating spontaneous deletion/duplication events involving Mid1. These data provide evidence for the first time that genetic instability of the PAR may affect functionally important genes. In addition, we show that MID1 is the first example of a gene subject to X-inactivation in man while escaping it in mouse. These data contribute to a better understanding of the molecular content and evolution of the rodent PAR.      

The effects of antioxidant supplementation during Percoll preparation on human sperm DNA integrity

The integrity of sperm DNA is crucial for the maintenance of genetic health. A major source of damage is reactive oxygen species (ROS) generation; therefore, antioxidants may afford protection to sperm DNA. The objectives of the study were, first, to measure the effects of antioxidant supplementation in vitro on endogenous DNA damage in spermatozoa using the single cell gel electrophoresis (comet) assay and, second, to assess the effect of antioxidant supplementation given prior to X-ray irradiation on induced DNA damage. Spermatozoa from 150 patients were prepared by Percoll centrifugation in the presence of ascorbic acid (300, 600 microM), alpha tocopherol (30, 60 microM), urate (200, 400 microM), or acetyl cysteine (5, 10 microM). DNA damage was induced by 30 Gy X-irradiation. DNA strand breakage was measured using the comet assay. Sperm DNA was protected from DNA damage by ascorbic acid (600 microM), alpha tocopherol (30 and 60 microM) and urate (400 microM). These antioxidants provided protection from subsequent DNA damage by X-ray irradiation. In contrast, acetyl cysteine or ascorbate and alpha tocopherol together induced further DNA damage. Supplementation in vitro with the antioxidants ascorbate, urate and alpha tocopherol separately has beneficial effects for sperm DNA integrity.      

A study of HLA (Bg) on red cells and platelets by immunoblotting with monoclonal antibodies

HLA class I antigens (Bg) on red cells (RBCs) are expressed by some normal donors and by many patients with systemic lupus erythematosus (SLE). To identify the membrane components previously detected by hemagglutination with HLA class I-specific monoclonal antibodies (MoAbs), RBC membrane preparations were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotted with the HLA class I MoAbs. Two components were obtained that reacted with the MoAbs: a heavy chain of 45 kDa and a light chain termed beta2-microglobulin (beta2-M) of 11 kDa. The effect of chloroquine and acid elution in stripping HLA antigens is shown to be due to the removal of beta2-M, as only that component was detected in eluates from reactive RBCs. Neither antibody elution method affected the heavy chain expression assessed by immunoblotting. It is concluded that HLA class I antigens on RBCs are integral membrane components of the type normally found and wisely distributed on many nucleated cells. Platelets, which have stronger HLA class I antigen expression, were also studied, and their membrane preparations yielded heavy chain and beta2-M molecules; the effect of chloroquine treatment was harder to assess than that of acid elution, owing to the sensitivity with which both components are detected in immunoblotting. In eluates obtained from acid treatment only beta2-M is detected.     

Surface membrane vesicles from mononuclear cells stimulate erythroid stem cells to proliferate in culture

In order to examine the contribution of cell surface materials to erythroid burst-promoting activity (BPA), we separated media conditioned by a variety of human cell types into pellets and supernatants by centrifugation. When added to serum-restricted cultures of nonadherent human marrow cells, pellets contained about half of the total stimulatory activity. Freeze-fracture electron microscopy of the pellets revealed the presence of unilamellar membrane vesicles ranging from 0.10 to 0.40 microM in diameter. The amount of BPA in culture increased with added vesicle concentration in a saturable fashion. Preparation of leukocyte conditioned medium (LCM) from 125I-wheat germ agglutinin labeled cells and studies comparing the glycoprotein composition of vesicles with that of leukocyte plasma membranes suggest that LCM-derived vesicles are of plasma membrane origin. Moreover, partially purified leukocyte plasma membrane preparations also contained BPA. While disruption of vesicles by freezing/thawing and hypotonic lysis did not alter BPA, heat, trypsin, or pronase treatment removed greater than 65% of BPA, implying that vesicle surface rather than intravesicular molecules express BPA. Results of BPA assays performed in two-layer clots indicated that proximity to target cells is required for vesicle BPA expression. We conclude that membrane vesicles spontaneously shed from cell surfaces may be important regulators of erythroid burst proliferation in vitro.     

Predictors of timing of pregnancy discovery

Objective

Earlier pregnancy discovery is important in the context of prenatal and abortion care. We evaluated characteristics associated with later pregnancy discovery among women seeking abortion care.

难治性青光眼两种治疗方法的比较

临床资料 2003-02／2004—10，难治性青光眼36例36眼，(男19，女17)例；年龄37—81(平均59．6)岁；术前视力：无光感6例，光感15例，手动13例，眼前数指2例；术前眼压：在5．59—10．77(平均8．01)kPa；1例系玻切术后继发性青光眼，35例系新生血管性青光眼(其中：视网膜静脉阻塞15例，糖尿病视网膜病变18例，原因不明2例)．①眼内窥镜下睫状体光凝术18例：在角膜缘环形剪开结膜，充分止血；在     

Safety,pharmacokinetics, and activity of EZN‐2208, a novel conjugate of polyethylene glycol and SN38, in patients with advanced malignancies

BACKGROUND:

EZN‐2208 is a water‐soluble, polyethylene glycol drug conjugate of SN38, which is the active moiety of irinotecan. In this study, the authors evaluated the tolerability, pharmacokinetics (PK), and activity of EZN‐2208 in adult patients with advanced solid tumors.

METHODS:

Patients in sequential cohorts (3 + 3 design) received intravenous EZN‐2208 at doses between 1.25 mg/m² and 25 mg/m² once every 21 days.

RESULTS:

Thirty‐nine patients received EZN‐2208. The median number of prior therapies was 2 (range, 0‐10 prior therapies). Seventeen patients received prior irinotecan. Two maximum tolerated doses (MTDs) were defined: EZN‐2208 with (16.5 mg/m²) and without (10 mg/m²) granulocyte‐colony–stimulating factor (G‐CSF). The dose‐limiting toxicity (DLT) was febrile neutropenia. Two of 19 patients who were heterozygous for a polymorphism in the uridine diphosphate glucuronosyltransferase 1 family, polypeptide A1 (UGT1A1) gene (UGT1A1*28) developed DLTs (dose, 25 mg/m² with G‐CSF), and 2 patients who were homozygous for UGT1A1*28 were treated without DLTs (dose, 5 mg/m²). PK analysis indicated a mean terminal half‐life of 19.4 ± 3.4 hours. Sixteen patients (41%) achieved stable disease, including 6 of 39 patients (15%) who had stable disease that lasted ≥4 months. One patient with cholangiocarcinoma (no prior irinotecan) achieved a short‐lived 32% tumor regression. Among 6 patients who had stable disease that lasted for ≥4 months, 3 had received prior irinotecan, and 1 had KRAS‐positive colorectal cancer.

CONCLUSIONS:

EZN‐2208 was well tolerated and produced stable disease that lasted for ≥4 months/unconfirmed partial responses in 7 of 39 heavily pretreated patients (18%) with advanced solid tumors, including those who had failed prior irinotecan therapy. Cancer 2012. © 2012 American Cancer Society.     

Decision aids for localized prostate cancer treatment choice: Systematic review and meta‐analysis

Patients who are diagnosed with localized prostate cancer need to make critical treatment decisions that are sensitive to their values and preferences. The role of decision aids in facilitating these decisions is unknown. The authors conducted a systematic review of randomized trials of decision aids for localized prostate cancer. Teams of 2 reviewers independently identified, selected, and abstracted data from 14 eligible trials (n = 3377 men), of which 10 were conducted in North America. Of these, 11 trials compared decision aids with usual care, and 3 trials compared decision aids with other decision aids. Two trials suggested a modest positive impact on decisional regret. Results across studies varied widely for decisional conflict (4 studies), satisfaction with decision (2 studies), and knowledge (2 studies). No impact on treatment choices was observed (6 studies). In conclusion, scant evidence at high risk of bias suggests the variable impact of existing decision aids on a limited set of decisional processes and outcomes. Because current decision aids provide information but do not directly facilitate shared decision making, subsequent efforts would benefit from user‐centered design of decision aids that promote shared decision making. CA Cancer J Clin 2015;65: 239–251. © 2015 American Cancer Society.