红细胞保存期影响早产儿疗效的随机对照试验:研究设计

尽管目前趋于逐渐降低输血阅值,并开发技术避免输注异体血液,但异体红细胞输注仍是罹患疾病和贫血的新生儿重症监护患者一个重要的支持和挽救生命的方法.     

Use of bacteriophage Ba1 to identify properties associated with Bordetella avium virulence

Bordetella avium causes bordetellosis, an upper respiratory disease of birds. Commercially raised turkeys are particularly susceptible. We report here on the use of a recently described B. avium bacteriophage, Ba1, as a tool for investigating the effects of lysogeny and phage resistance on virulence. We found that lysogeny had no effect on any of the in vivo or in vitro measurements of virulence we employed. However, two-thirds (six of nine) spontaneous phage-resistant mutants of our virulent laboratory strain, 197N, were attenuated. Phage resistance was associated, in all cases, with an inability of the mutants to bind phage. Further tests of the mutants revealed that all had increased sensitivities to surfactants, and increased amounts of incomplete (O-antigen-deficient) lipopolysaccharide (LPS) compared to 197N. Hot phenol-water-extracted 197N LPS inactivated phage in a specific and dose-dependent manner. Acid hydrolysis and removal of lipid A had little effect upon the ability of isolated LPS to inactivate Ba1, suggesting that the core region and possibly the O antigen were required for phage binding. All of the mutants, with one exception, were significantly more sensitive to naive turkey serum and, without exception, significantly less able to bind to tracheal rings in vitro than 197N. Interestingly, the three phage-resistant mutants that remained virulent appeared to be O antigen deficient and were among the mutants that were the most serum sensitive and least able to bind turkey tracheal rings in vitro. This observation allowed us to conclude that even severe defects in tracheal ring binding and serum resistance manifested in vitro were not necessarily indicative of attenuation and that complete LPS may not be required for virulence.     

The salivary microbiota as a diagnostic indicator of oral cancer: A descriptive,non-randomized study of cancer-free and oral squamous cell carcinoma subjects

Background  

The purpose of the present investigation was to determine if the salivary counts of 40 common oral bacteria in subjects with an oral squamous cell carcinoma (OSCC) lesion would differ from those found in cancer-free (OSCC-free) controls.     

Follow-up of abnormal screening mammograms among low-income ethnically diverse women: findings from a qualitative study

OBJECTIVE: To understand factors that women feel facilitate or hinder their receipt of diagnostic services following an abnormal screening mammogram. METHODS: This qualitative study used a purposive sampling strategy to identify low-income, ethnically diverse women aged 40 or over who had a recent abnormal mammogram. Working with a community health center, breast evaluation center, and mobile mammography van, 64 women were interviewed to identify salient themes that differentiated women who received timely follow-up from those who did not. RESULTS: Prominent themes among women who delayed follow-up included dissatisfaction with communication of results; perceived disrespect on the part of providers and clinic staff; logistical barriers to access of diagnostic services; anxiety and fear about a possible cancer diagnosis; and a lack of information about breast cancer screening and symptoms. Women who received timely care more often reported an appreciation of efforts by providers and clinic staff to support their prompt follow-up; availability of social support that facilitated appointment-keeping; confidence in their ability to advocate for their health; and a high priority placed on self-care. CONCLUSION: A comprehensive approach to improving timely diagnostic follow-up among underserved groups must address patient beliefs and attitudes, provider practices and communication, and practices at the health care systems level. PRACTICE IMPLICATIONS: Implications and strategies for improving patient education, patient-provider communication, and organizational practices are discussed.     

Elastin point mutations cause an obstructive vascular disease, supravalvular aortic stenosis

Supravalvular aortic stenosis (SVAS) is an inherited obstructive vascular disease that affects the aorta, carotid, coronary and pulmonary arteries. Previous molecular genetic data have led to the hypothesis that SVAS results from mutations in the elastin gene, ELN. In these studies, the disease phenotype was linked to gross DNA rearrangements (35 and 85 kb deletions and a translocation) in three SVAS families. However, gross rearrangements of ELN have not been identified in most cases of autosomal dominant SVAS. To define the spectrum of ELN mutations responsible for this disorder, we refined the genomic structure of human ELN and used this information in mutational analyses. ELN point mutations co-segregate with the disease in four familial cases and are associated with SVAS in three sporadic cases. Two of the mutations are nonsense, one is a single base pair deletion and four are splice site mutations. In one sporadic case, the mutation arose de novo. These data demonstrate that point mutations of ELN cause autosomal dominant SVAS.      

Interchromosomal duplications of the adrenoleukodystrophy locus: a phenomenon of pericentromeric plasticity

A 9.7 kb segment encompassing exons 7-10 of the adrenoleukodystrophy (ALD) locus of the X chromosome has duplicated to specific locations near the pericentromeric regions of human chromosomes 2p11,10p11, 16p11 and 22q11. Comparative sequence analysis reveals 92-96% nucleotide identity, indicating that the autosomal ALD paralogs arose relatively recently during the course of higher primate evolution (5-10 million years ago). Analysis of sequences flanking the duplication region identifies the presence of an unusual GCTTTTTGC repeat which may be a sequence-specific integration site for the process of pericentromeric- directed transposition. The breakpoint sequence and phylogenetic analysis predict a two-step transposition model, in which a duplication from Xq28 to pericentromeric 2p11 occurred once, followed by a rapid distribution of a larger duplicon cassette among the pericentromeric regions. In addition to facilitating more effective mutation detection among ALD patients, these findings provide further insight into the molecular basis underlying a pericentromeric-directed mechanism for non- homologous interchromosomal exchange.      

Elevated 5-HT 2A receptors in postmortem prefrontal cortex in major depression is associated with reduced activity of protein kinase A

Previous human postmortem brain tissue research has implicated abnormalities of 5-HT receptor availability in depression and suicide. Although altered abundance of 5-HT 1A, 5-HT 2A, and 5-HT 2C receptors (5-HT_1A, 5-HT_2A, and 5-HT_2C) has been reported, the causes remain obscure. This study evaluated the availability of these three receptor subtypes in postmortem brain tissue specimens from persons with a history of major depression (MDD) and normal controls and tested the relationships to protein kinases A and C (PKA, PKC). Samples were obtained from postmortem brain tissue (Brodmann area 10) from 20 persons with a history of MDD and 20 matched controls as determined by a retrospective diagnostic evaluation obtained from family members. Levels of 5-HT_1A, 5-HT_2A, and 5-HT_2C receptor were quantitated via Western blot analyses. Basal and stimulated PKA and PKC activity were also determined. The depressed samples showed significantly increased 5-HT_2A receptor abundance relative to controls, but no differences in 5-HT_1A or 5-HT_2C receptors. Basal and cyclic AMP-stimulated PKA activity was also reduced in the depressed sample; PKC activity was not different between groups. 5-HT_2A receptor availability was significantly inversely correlated with PKC activity in controls, but with PKA activity in the depressed sample. Increased 5-HT_2A receptor abundance and decreased PKA activity in the depressed sample are consistent with prior reports. The correlation of 5-HT_2A receptor levels with PKA activity in the depressed group suggests that abnormalities of 5-HT_2A receptor abundance may depend on receptor uncoupling and heterologous regulation by PKA.     

Influence of calcium phosphate crystal morphology on the adhesion, spreading, and growth of bone derived cells

In this study, rat periosteal cells and bone marrow stromal cells (BMSC) were examined when cultured on octacalcium phosphate (OCP) crystals to determine the effects of crystal morphology on their adhesion, spreading, and growth. Three type of OCP crystals with different morphology were prepared by different precipitation methods. OCPI was prepared by homogeneous precipitation; while OCPII and III were prepared by heterogeneous precipitation dripping a calcium ion containing solution into a phosphate ion solution or vice versa, respectively. The effects of crystal morphology on the attachment and spreading of cultured cells on OCP crystals were observed using SEM. The effects of crystal morphology on the growth of periosteal cell or BMSC were evaluated using the MTT assay, while OCP crystal cytotoxicity was determined by measuring lactic dehydrogenase (LDH) released from 2.12 x 10(5) cells incubated with 60 mg of the different OCPs. BMSCs and periosteal cells attached to or between the crystals of OCPI and the cell number increased over the 17 days of culture. In contrast, cell numbers could not be measured for either periosteal cells or BMSC on OCPII and III. BMSC incubated with OCPII and III showed a higher rate of LDH release, compared with the cells incubated with OCPI. This study demonstrated that the morphology of OCP crystals influenced the attachment, spreading and growth of periosteal cells and BMSC.     

Lower rates of low birthweight and preterm births in the California Black Infant Health Program

OBJECTIVES: The objective of this study was to determine the impact of prenatal interventions in the California Black Infant Health (BIH) Program on low birthweight (LBW) and preterm births (PTB) outcomes. METHODS: A prospective observational study design with a comparison group was used. BIH participants with a delivery recorded between July 1996 and September 1998 were included in the birthweight and PTB analyses. These outcomes for BIH participants who entered the BIH program prior to 32 weeks' gestation (n=1,553) were compared to those of all African-American women in the BIH Program targeted ZIP codes (n=11,633). RESULTS: No statistically significant differences in LBW and PTB were found between the BIH population and the comparison group. However, a comparison of the BIH infant VLBW (<1,500 g) rate (1.9%) with the VLBW rate for the comparison group (3.0%) shows that the BIH rate is 63% of the comparison group rate. For very PTB (<32 weeks), the BIH rate (3.5%) is 81% of the comparison group rate (4.3%). BIH participants had higher risk profiles (pregnancy history, current pregnancy, and psychosocial; p=<0.01) than women in the comparison group. CONCLUSIONS: The BIH Program retained high-risk women in the program to delivery and assisted them with maintenance of prenatal care. Even though the program participants were higher risk, their LBW and PTB outcomes were comparable to the geographic area overall. More importantly, there was a trend among women in the BIH Program toward better outcomes than the comparison group in both VLBW and VPTB.