Anisotropic diffusion properties in infants with hydrocephalus: a diffusion tensor imaging study

BACKGROUND AND PURPOSE

Diffusion tensor imaging (DTI) can noninvasively detect in vivo white matter (WM) abnormalities on the basis of anisotropic diffusion properties. We analyzed DTI data retrospectively to quantify the abnormalities in different WM regions in children with hydrocephalus during early infancy.

MATERIALS AND METHODS

Seventeen infants diagnosed with hydrocephalus (age range, 0.13-16.14 months) were evaluated with DTI and compared with 17 closely age-matched healthy children (age range, 0.20-16.11 months). Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity, and radial diffusivity values in 5 regions of interest (ROIs) in the corpus callosum and internal capsule were measured and compared. The correlation between FA and age was also studied and compared by ROI between the 2 study groups.

RESULTS

Infants with hydrocephalus had significantly lower FA, higher MD, and higher radial diffusivity values for all 3 ROIs in the corpus callosum, but not for the 2 ROIs in the internal capsule. In infants with hydrocephalus, the increase of FA with age during normal development was absent in the corpus callosum but was still preserved in the internal capsule. There was also a significant difference in the frequency of occurrence of abnormal FA values in the corpus callosum and internal capsule.

CONCLUSIONS

This retrospective DTI study demonstrated significant WM abnormalities in infants with hydrocephalus in both the corpus callosum and internal capsule. The results also showed evidence that the impact of hydrocephalus on WM was different in the corpus callosum and internal capsule.

Rap1b is critical for glycoprotein VI-mediated but not ADP receptor-mediated alpha2beta1 activation

BACKGROUND

The platelet alpha2beta1 integrin functions as both an adhesion and signaling receptor upon exposure to collagen. Recent studies have indicated that alpha2beta1 function can be activated via inside-out signaling, similar to the prototypical platelet integrin alphaIIbbeta3. However, signaling molecules that regulate alpha2beta1 activation in platelets are not well defined. A strong candidate molecule is the small GTPase Rap1b, the dominant platelet isoform of Rap1, which regulates alphaIIbbeta3 activation.

OBJECTIVES

We hypothesized that Rap1b positively regulates alpha2beta1 during agonist-induced platelet activation.

METHODS

To test whether Rap1b activates alpha2beta1 downstream of glycoprotein (GP)VI or other platelet receptors, we stimulated platelets purified from Rap1b-/- or wild-type mice with diverse agonists and measured alpha2beta1 activation using fluorescein isothiocyanate-labeled monomeric collagen. We also examined the role of Rap1b in outside-in signaling pathways by analyzing adhesion and spreading of Rap1b-/- or wild-type platelets on monomeric, immobilized collagen. Finally, we monitored the activation status of related Rap GTPases to detect changes in signaling pathways potentially associated with Rap1b-mediated events.

RESULTS

Rap1b-/- platelets displayed comparable ADP-induced or thrombin-induced alpha2beta1 activation as wild-type platelets, but reduced convulxin-dependent alpha2beta1 activation. Rap1b-/- platelets exhibited increased spreading on immobilized collagen but similar adhesion to immobilized collagen compared to wild-type platelets. Rap1b-/- platelets also showed Rap1a and Rap2 activation upon agonist stimulation, possibly revealing functional compensation among Rap family members.

CONCLUSIONS

Rap1b is required for maximal GPVI-induced but not ADP-induced activation of alpha2beta1 in murine platelets.

Polymorphisms in the interleukin 3 gene show strong association with susceptibility to Graves' disease in Chinese population

Graves' disease (GD) is a common organ-specific autoimmune disorder, which is multifactorial and develops in genetically susceptible individuals. We had earlier mapped a susceptibility locus for GD to chromosome 5q31-33 in a linkage study. Here we used tag single-nucleotide polymorphisms (SNPs) to search for genetic variants associated with GD, and examined 19 functional candidate genes in this chromosomal region. We identified 192 polymorphisms by re-sequencing the candidate genes, and selected 51 tagSNPs to genotype in a case-control collection of 1118 south Han Chinese subjects (428 cases and 690 controls). Initial analysis suggested that a non-synonymous SNP rs40401 (P27S) of interleukin 3 (IL3) was associated with GD, and further fine-mapping showed that rs40401, or its perfect proxy SNP rs31480 in the 5' flanking region of IL3, fully accounted for the association signal at this locus. We replicated significant association of rs40401 with GD in an independent sample collection of 839 north Han Chinese subjects. A combined analysis revealed strong validation of this association (odds ratio (OR(common))=1.63, combined P (P(comb))=4 x 10(-6) in the Recessive disease model). This study provides convincing evidence that the IL3 gene is a susceptibility locus for GD in the Chinese population.

Effect of the degree of fragmentation on embryo survival after freeze-thawing

PURPOSE

To determine if the degree of fragmentation of embryos prior to freezing correlate in a negative manner with survival after thawing.

METHODS

A retrospective review of frozen embryos thawed for purposes of embryo transfer was done. Survival and transferability rates were determined according to degree of fragmentation.

RESULTS

The chance that an embryo with < 25% fragmentation was deemed good enough for transfer upon thawing was 63.6% compared to 52.8% for embryos > 25% (p < .05).

CONCLUSIONS

Though more fragmented embryos have a lower survival rate after freeze thawing, about 50% of embryos with > 25% fragmentation will still survive the thaw and be able to be transferred.

Comparison of the efficacy of selecting sperm with normal nuclei by high magnification for intracytoplasmic sperm injection (ICSI) according to age in refractory in vitro fertilization (IVF) cases

PURPOSE

To determine the pregnancy rates according to age in women failing to conceive after three previous embryo transfers or having a husband whose sperm shows a DNA fragmentation index (DFI) > 30% when performing the sperm chromatin structure assay.

METHODS

Women up to age 45 were included and there was no restriction for low egg reserve. Live delivered pregnancy rates were determined according to three age groups: < or =34, 35-38, 39-45. The data were also analyzed in a group comparable to previous publications using high magnification ICSI, i.e., younger women with normal egg reserve. Pregnancy rates following frozen embryo transfer were also evaluated.

RESULTS

Using all 86 in vitro fertilization-embryo transfer (IVF-ET) cycles the live delivered pregnancy rates were 40% (10/25) for women < or = age 34, 24% (6/25) in women age 35-38, and 13.8% in women aged 39-45. Evaluating the younger group with normal egg reserve with > or =3 previous failed IVF-ET cycles the live delivered pregnancy rate per transfer was 38% (16/42). If one adds the additional six live deliveries from subsequent frozen embryo transfer (6 of 17, 35.3%) this group of women had a 52.3% (22/42) live delivered pregnancy rate from one egg retrieval.

CONCLUSIONS

These data were uncontrolled and thus conclusions should be viewed with caution. The results are sufficiently encouraging to warrant a prospective controlled trial and possibly encourage a company to consider commercially manufacturing high magnification microscopes.

A comparison of efficacy of freezing embryos at the 2 pronuclear (2PN) stage vs multi-cell when using a simplified freezing protocol with one-step removal of cryoprotectant

PURPOSE

To compare the efficacy of freezing embryos at the 2 pronuclear stage vs multi-cell stage using a simplified freezing protocol with a one-step removal of the cryoprotectant.

METHODS

A retrospective analysis was performed. Survival, delivered pregnancy and implantation rates were compared in transfers of all embryos frozen at 2 pronuclear stage (2PN) or all embryos frozen at multi-cell stage. The results were further stratified and compared according to the number of high quality embryos transferred.

RESULTS

In all categories despite comparing similar numbers and quality of embryos transferred there was a significantly higher survival rate of 2PN embryos. Significantly higher delivered pregnancy and implantation rates were seen with 2PN vs multi-cell embryos when there was only one or two embryos with > or = 6 blastomeres and < 25% fragmentation, and a trend for higher delivered pregnancy rates when there were three top quality embryos transferred.

CONCLUSIONS

When given the option it is preferable when using this simplified freezing and thawing protocol to freeze at the 2PN stage.

Pregnancy rates per embryo transfer (ET) may be improved by conventional oocyte insemination for male factor rather than intracytoplasmic sperm injection (ICSI)

PURPOSE

To determine if intracytoplasmic sperm injection (ICSI) for mild male factor may create embryos less likely to implant.

METHOD

A retrospective analysis of pregnancy outcome following oocyte fertilization with ICSI vs conventional egg insemination was performed.

RESULTS

Though there were many less cases using conventional oocyte insemination compared to ICSI so that a meaningful comparison of outcome could not be made, the data could suggest the fertilization by ICSI might result in embryos less likely to implant.

CONCLUSIONS

This pilot study should encourage IVF centers to consider conventional oocyte insemination for mild male factor instead of ICSI. Only by evaluating a larger series can it be determined with certainty that fertilization by ICSI may lower the implantation potential of the embryo that is formed.

The effect of blastomere number on embryo survival upon freezing/thawing

PURPOSE

To determine if the blastomere number of embryos at the time of freezing is related to its quality post-thaw.

METHODS

A retrospective cohort analysis of frozen/thawed embryos. Only multi-cell embryos were used for this study. If an embryo was of good quality it would either be transferred or re-frozen.

RESULTS

There did not appear to be any trend for a lower percentage of good quality embryos with fewer numbers of blastomeres.

CONCLUSIONS

Though 4-cell embryos have a markedly lower implantation potential upon fresh embryo transfer compared to 6-8-cell embryos, this is not reflected in their ability to survive freeze-thawing.

Comparison of SNR and CNR for in vivo mouse brain imaging at 3 and 7 T using well matched scanner configurations

Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) for magnetic resonance microimaging were measured using two nearly identical magnetic resonance imaging (MRI) scanners operating at field strengths of 3 and 7 T. Six mice were scanned using two imaging protocols commonly applied for in vivo imaging of small animal brain: RARE and FLASH. An accounting was made of the field dependence of relaxation times as well as a small number of hardware disparities between scanner systems. Standard methods for relaxometry were utilized to measure T1 and T2 for two white matter (WM) and two gray matter (GM) regions in the mouse brain. An average increase in T1 between 3 and 7 T of 28% was observed in the brain. T2 was found to decrease by 27% at 7 T in agreement with theoretical models. The SNR was found to be uniform throughout the mouse brain, increasing at higher field by a factor statistically indistinguishable from the ratio of Larmor frequencies when imaging with either method. The CNR between GM and WM structures was found to adhere to the expected field dependence for the RARE imaging sequence. Improvement in the CNR for the FLASH imaging sequence between 3 and 7 T was observed to be greater than the Larmor ratio, reflecting a greater susceptibility to partial volume effects at the lower SNR values at 3 T. Imaging at 7 T versus 3 T in small animals clearly provides advantages with respect to the CNR, even beyond the Larmor ratio, especially in lower SNR regimes. This careful multifaceted assessment of the benefits of higher static field is instructive for those newly embarking on small animal imaging. Currently the number of 7 T MRI scanners in use for research in human subjects is increasing at a rapid pace with approximately 30 systems deployed worldwide in 2008. The data presented in this article verify that if system performance and radio frequency uniformity is optimized at 7 T, it should be possible to realize the expected improvements in the CNR and SNR compared with MRI at 3 T.

Chinese herbal medicine Huangqi type formulations for nephrotic syndrome

BACKGROUND

At present, there is a lack of safe and effective drugs for nephrotic syndrome (NS). Huangqi type formulations have been used to treat nephrotic syndrome for years in China, however the effects and safety of these formulations have not been systematically reviewed.

OBJECTIVES

To assess the benefits and harms of Huangqi and Huangqi type formulations in treating NS in any age group, either as sole agents or in addition to other drug therapies.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Chinese Biomedicine Database (CBM), CNKI, VIP and reference lists of articles. There was no language restriction. Date of most recent search: June 2006.

SELECTION CRITERIA

All randomised controlled trials (RCTs) assessing the use of Huangqi or Huangqi type formulations in treating NS in adults and children, either as sole agents or in addition to other drug therapies.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. For dichotomous outcomes (remission, side effects and Inefficacy rate), results were expressed as relative risk (RR) and 95% confidence intervals (CI). Continuous outcomes (triglycerides cholesterol, plasma albumin) results were expressed as mean difference (WMD) with 95% CI.

MAIN RESULTS

Three studies were identified (n = 128), all comparing Huangqi type formulations with placebo. Huangqi injection had a positive effect on plasma albumin (WMD 6.90, 95% Cl 3.60 to 10.20) and cholesterol (WMD 2.13, 95% Cl -2.97 to -1.29). Huangqi and red Chinese date reduced some adverse reactions (Cushing's syndrome: RR 0.55, 95% Cl 0.32 to 0.94; hormone reduced syndrome: RR 0.58, 95% Cl 0.39 to 0.85, respiratory tract infection: RR 0.27, 95% Cl 0.08 to 0.88), but no benefit on reducing relapse. Huangqi and Danggui had a positive effect on cholesterol (WMD -0.85, 95% Cl -1.70 to 0.00).

AUTHORS' CONCLUSIONS

Huangqi type formulations may have some positive effects in treating NS by increasing plasma albumin and reducing blood cholesterol, Cushing's syndrome, hormone reduced syndrome and respiratory tract infection. However, limited by the lack of high quality clinical studies, we are unable to recommend Huangqi type formulations for NS. Large, properly randomised, placebo-controlled, double-blind studies are required.

Vitamin A for preventing acute lower respiratory tract infections in children up to seven years of age

BACKGROUND

Vitamin A supplements are effective for preventing diarrhoea. There are theoretical reasons it might also be effective for acute lower respiratory tract infections (LRTIs), also very common in children, especially in low income countries.

OBJECTIVES

To assess the effectiveness and safety of vitamin A for preventing acute LRTIs in children up to seven years of age.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, Issue 2); MEDLINE (1966 to July 2007); EMBASE (1974 to July 2007); and the Chinese Biomedicine Database (CBM) (1976 to July 2007).

SELECTION CRITERIA

Randomised controlled trials (RCTs) that assessed the effectiveness of vitamin A in the prevention of acute LRTI in children up to seven years of age.

DATA COLLECTION AND ANALYSIS

The review authors independently extracted data and assessed trial quality. Study authors were contacted for additional information.

MAIN RESULTS

Most studies found no significant effect of vitamin A on the incidence of acute LRTI, or prevalence of symptoms of acute LRTI. Vitamin A caused an increased incidence of acute LRTI in one study; an increase in cough and fever; and increased symptoms of cough and rapid breathing in two others. Three reported no differences and no protective effect of vitamin A. Two studies reported that vitamin A significantly reduced the incidence of acute LRTI with children with poor nutritional status or weight, but increased it in normal children.

AUTHORS' CONCLUSIONS

This unexpected result is outside our current understanding of the use of vitamin A for preventing acute LRTIs. Accordingly, vitamin A should not be given to all children to prevent acute LRTIs. There is evidence for vitamin A supplements to prevent acute LRTIs in children with low serum retinol or those with a poor nutritional status.

Improving the sensitivity limit of surface plasmon resonance biosensors by detecting mixed interference signals

We demonstrate that the sensitivity limit of intensity-based surface plasmon resonance (SPR) biosensors can be enhanced when we combine the effects of the phase and amplitude contributions instead of detecting the amplitude variation only. Experimental results indicate that an enhancement factor of as much as 20 times is achievable, yet with no compromise in measurement dynamic range. While existing SPR biosensor systems are predominantly based on the angular scheme, which relies on detecting intensity variations associated with amplitude changes only, the proposed scheme may serve as a direct system upgrade approach for these systems. The new measurement scheme may therefore lead to a strong impact in the design of SPR biosensors.

Corticobasal syndrome and primary progressive aphasia as manifestations of LRRK2 gene mutations

BACKGROUND

Mutations in the LRRK2 gene are an important cause of familial and nonfamilial parkinsonism. Despite pleomorphic pathology, LRRK2 mutations are believed to manifest clinically as typical Parkinson disease (PD). However, most genetic screens have been limited to PD clinic populations.

OBJECTIVE

To clinically characterize LRRK2 mutations in cases recruited from a spectrum of neurodegenerative diseases.

METHODS

We screened for the common G2019S mutation and several additional previously reported LRRK2 mutations in 434 individuals. A total of 254 patients recruited from neurodegenerative disease clinics and 180 neurodegenerative disease autopsy cases from the University of Pennsylvania brain bank were evaluated.

RESULTS

Eight cases were found to harbor a LRRK2 mutation. Among patients with a mutation, two presented with cognitive deficits leading to clinical diagnoses of corticobasal syndrome and primary progressive aphasia.

CONCLUSION

The clinical presentation of LRRK2-associated neurodegenerative disease may be more heterogeneous than previously assumed.

Diffusion tensor MR imaging reveals persistent white matter alteration after traumatic brain injury experienced during early childhood

BACKGROUND AND PURPOSE

Diffusion tensor imaging (DTI) can noninvasively quantify white matter (WM) integrity. Although its application in adult traumatic brain injury (TBI) is common, few studies in children have been reported. The purposes of this study were to examine the alteration of fractional anisotropy (FA) in children with TBI experienced during early childhood and to quantify the association between FA and injury severity.

MATERIALS AND METHODS

FA was assessed in 9 children with TBI (age = 7.89 +/- 1.00 years; Glasgow Coma Scale [GCS] = 10.11 +/- 4.68) and a control group of 12 children with orthopedic injuries without central nervous system involvement (age = 7.51 +/- 0.95 years). All of the subjects were at minimum 12 months after injury. We examined group differences in a series of predetermined WM regions of interest with t test analysis. We subsequently conducted a voxel-wise comparison with Spearman partial correlation analysis. Correlations between FA and injury severity were also calculated on a voxel-wise basis.

RESULTS

FA values were significantly reduced in the TBI group in genu of corpus callosum (CC), posterior limb of internal capsule (PLIC), superior longitudinal fasciculus (SLF), superior fronto-occipital fasciculus (SFO), and centrum semiovale (CS). GCS scores were positively correlated with FA in several WM areas including CC, PLIC, SLF, CS, SFO, and inferior fronto-occipital fasciculus (IFO).

CONCLUSION

This DTI study provides evidence that WM integrity remains abnormal in children with moderate-to-severe TBI experienced during early childhood and that injury severity correlated strongly with FA.

1,25-Dihydroxyvitamin D3 targeting of NF-kappaB suppresses high glucose-induced MCP-1 expression in mesangial cells

Macrophages accumulate in kidney glomeruli and interstitium of patients with diabetic nephropathy in response to monocyte chemoattractant protein-1 (MCP-1); a chemokine produced by both tubular epithelial and mesangial cells (MCs). Vitamin D and its analogs have been shown to have renoprotective effects; however, there are few studies involving diabetic nephropathy. We explored mechanisms by which 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) can be renoprotective by measuring MCP-1 expression in MCs. Using a luciferase reporter assay, we found that high glucose (HG)-induced MCP-1 transcription and that this induction is blocked by 1,25(OH)2D3. Electrophoretic mobility shift and chromatin immunoprecipitation assays showed that HG increased the p65/p50 binding to the two NF-kappaB sites within the promoter. This was suppressed by 1,25(OH)2D3, but this decrease was reversed by overexpression of p65. 1,25(OH)2D3 was found to stabilize IkappaBalpha leading to an inhibition of p65 translocation to the nucleus and subsequent reduction of NF-kappaB binding. In primary MCs prepared from vitamin D receptor knockout animals, basal MCP-1 levels were elevated but not affected by 1,25(OH)2D3. The analog paricalcitol inhibited the induction and activity of MCP-1 while ameliorating glomerulosclerosis in streptozotocin-diabetic mice. Our results suggest that 1,25(OH)2D3 might block hyperglycemia-induced renal injury by blunting NF-kappaB activation.

Two-dimensional biosensor arrays based on surface plasmon resonance phase imaging

We present a biosensor design based on capturing the two-dimensional (2D) phase image of surface plasmon resonance (SPR). This 2D SPR imaging technique may enable parallel label-free detection of multiple analytes and is compatible with the microarray chip platform. This system uses our previously reported differential phase measurement approach, in which 2D phase maps obtained from the signal (P) and reference (S) polarizations are compared pixel by pixel. This technique greatly improves detection resolution as the subtraction step can eliminate measurement fluctuations caused by external disturbances as they essentially appear in both channels. Unlike conventional angular SPR systems, in which illumination from a range of angles must be used, phase measurement requires illumination from only one angle, thus making it well suited for 2D measurement. Also, phase-stepping introduced from a moving mirror provides the necessary modulation for accurate detection of the phase. In light of the rapidly increasing need for fast real-time detection, quantification, and identification of a range of proteins for various biomedical applications, our 2D SPR phase imaging technique should hold a promising future in the medical device market.

A novel transcript of the LMO2 gene, LMO2-c, is regulated by GATA-1 and PU.1 and encodes an antagonist of LMO2

Ectopic expression of LIM-only protein 2 (LMO2) in T-cells, as a result of chromosomal translocations or retroviral insertion, plays an important role in the onset of T-cell leukemias. Two transcripts of LMO2 gene (LMO2-a and LMO2-b) have been reported to encode a same 158-amino-acid protein. We have previously reported a novel transcript of human LMO2 gene (LMO2-c) encoding a 151-amino-acid protein, and defined its promoter region. In the present study, we investigated the regulation of the LMO2-c expression and the functions of LMO2-c. We found that LMO2-c expression is regulated by the cooperation of two essential hematopoietic transcription factors GATA-1 and PU.1 in various hematopoietic cell lines, suggesting an important functional role for LMO2-c in the hematopoietic system. More importantly, we demonstrated that LMO2-c acts as an antagonist of LMO2-a/b binding to its partners, therefore blocking the transactivation of LMO2-a/b on its target genes. These findings provide novel evidence to the functions of LMO2 gene in the hematopoietic system and leukemia.