cDNA-RDA of genes expressed in fetal and adult lungs identifies factors important in development and function. (17/1051)

The identification of genetic factors important in lung development and function will help in understanding the underlying molecular mechanisms of respiratory disease. Representational difference analysis of cDNA (cDNA-RDA) is a PCR-based subtractive enrichment procedure for the isolation of differentially expressed genes. We performed cDNA-RDA and isolated genes expressed more abundantly in fetal and adult lungs. Fifty-four clones potentially representing genes with higher transcript levels in the fetal lung were sequenced. Sequence similarity searches indicated that these clones included 12 known genes, a discoidin-like domain-containing gene, six expressed sequence tags (ESTs), and one novel sequence. Fifty-six clones potentially representing genes expressed more abundantly in the adult lung were also cloned and sequenced. Of these, 16 known human genes were represented along with two sequences significantly similar to known mouse genes and two novel sequences. Several of these known genes are implicated in stress response and lung protection. Thus cDNA-RDA was successfully used to isolate known and novel differentially expressed genes, which putatively play an important role in human lung development.  (+info)

Low-cost soft-copy display accuracy in the detection of pulmonary nodules by single-exposure dual-energy subtraction: comparison with hard-copy viewing. (18/1051)

This study endeavored to clarify the usefulness of single-exposure dual-energy subtraction computed radiography (CR) of the chest and the ability of soft-copy images to detect low-contrast simulated pulmonary nodules. Conventional and bone-subtracted CR images of 25 chest phantom image sets with a low-contrast nylon nodule and 25 without a nodule were interpreted by 12 observers (6 radiologists, 6 chest physicians) who rated each on a continuous confidence scale and marked the position of the nodule if one was present. Hard-copy images were 7 x 7-inch laser-printed CR films, and soft-copy images were displayed on a 21-inch noninterlaced color CRT monitor with an optimized dynamic range. Soft-copy images were adjusted to the same size as hard-copy images and were viewed under darkened illumination in the reading room. No significant differences were found between hard- and soft-copy images. In conclusion, the soft-copy images were found to be useful in detecting low-contrast simulated pulmonary nodules.  (+info)

Carotid and transcranial color-coded duplex sonography in different types of carotid-cavernous fistula. (19/1051)

BACKGROUND AND PURPOSE: Patients with carotid-cavernous fistula (CCF) may undergo direct or indirect shunting. Ultrasonography has value that is complementary to angiography in the assessment and follow-up of these patients. The aim of this study was to characterize findings provided by carotid duplex sonography (CDS) and transcranial color-coded duplex sonography (TCCD) in patients with different types of CCF. METHODS: CDS and TCCD were independently performed by technologists and neurologists. Digital subtraction or MR angiography was interpreted by a neuroradiologist. Ultrasonographic studies were categorized into 4 types: I, direct shunting only; II, direct shunting with a carotid aneurysm; III, indirect shunting only; and IV, mixed (direct and indirect) shunting. In addition to carotid and intracranial flow velocities, volume, and pulsatility, other direct and indirect ultrasound signs of shunting were evaluated. The direct sign of CCF was a mosaic flash detected by TCCD. Alteration of hemodynamic parameters on CDS and demonstration of draining veins with the use of TCCD were considered indirect signs. RESULTS: Fifteen patients (8 men, 7 women) were included in the study. According to angiographic results, patients in ultrasonographic classification types I (n=7) and II (n=3) corresponded to type A of Barrow's classification. Patients with type III (n=8) were Barrow's type C. Type IV (n=1) had a combination of Barrow's types A and C. On ultrasound, both direct and indirect signs were seen in types I, II, and IV CCF. The presence of a 2-colored oval mass divided by a zone of separation without turbulence differentiated type I from type II CCF. All patients with type III CCF had indirect signs, and only 1 patient had direct signs on TCCD. Abnormal TCCD findings were most commonly seen through the transorbital window (100%), followed by the transtemporal window (63%) and transforaminal window (40%). CONCLUSIONS: If only indirect ultrasonographic signs of CCF are present, TCCD can be used to predict an indirect CCF type on the basis of the origin of the fistula. With direct communication between carotid artery and cavernous sinus, both direct and indirect ultrasonographic signs can be found. The combination of CDS/TCCD may provide a noninvasive and reliable way to classify patients with CCF.  (+info)

Identification of iron responsive genes by screening cDNA libraries from suppression subtractive hybridization with antisense probes from three iron conditions. (20/1051)

The goal of the present study is to identify genes that respond to iron availability. Suppression subtraction hybridization (SSH) was used to generate cDNA libraries from iron loaded and control human astrocytoma cells (SW1088). The cDNA libraries were screened with antisense cDNA probes obtained from mRNA isolated from astrocytoma cells exposed to three conditions: (i) normal media (control), (ii) deferox-amine treated (iron deficient) or (iii) iron loaded. The screening of the cDNA libraries with antisense probes from the three conditions enhanced the screening efficiency and decreased the number of false positives. Positive clones were identified and sequenced. The genes of interest were further analyzed by determining changes in hybridization signal on northern blots from astrocytoma cells exposed to iron or deferoxamine over different time intervals. Our analysis identified cDNAs corresponding to known iron responsive genes such as L-chain ferritin, but also revealed a number of mRNAs with novel sequences and mRNAs previously not known to be responsive to iron such as one of the ABC transporters and Thy-1 glycoprotein. Thus our results suggest that the expression of a number of genes may be influenced by changes in iron availability.  (+info)

Screening poly(dA/dT)- cDNAs for gene identification. (21/1051)

Many genes expressed in the human genome have not been identified despite intensive efforts. We observed that the presence of long poly(dA/dT) sequences in the 3' end of cDNA templates contributes significantly to this problem, because the hybrids formed randomly between poly(dA) and poly(dT) sequences of unrelated cDNA templates lead to loss of many templates in the normalization/subtraction reactions. The low abundant copies, which account for the majority of the expressed genes, are affected in particular by this phenomenon. We have developed a strategy called screening poly(dA/dT)(-) cDNAs for gene identification to overcome this obstacle. Applying this strategy can significantly enhance the efficiency of genome-wide gene identification and should have an impact on many functional genomic studies in the postgenome era.  (+info)

A new predictive factor for hepatocellular carcinoma based on two-dimensional electrophoresis of genomic DNA. (22/1051)

Molecular genetic analyses have clarified that accumulation of genomic changes provides important steps in carcinogenesis and have identified a number of valuable genetic markers for certain cancers. To date, however, no prognostic markers have been identified for hepatocellular carcinoma (HCC). In this study, we used restriction landmark genomic scanning (RLGS), a new high-speed screening method for multiple genomic changes, to detect unknown genetic alterations in HCC. Thirty-one HCC samples and their normal counterparts were examined by RLGS. Eight spot changes were common in several cases, and all were seen only on the HCC profile. Five of these spots were detected in more than 12 of 31 cases (38.7%). Viral infection had no influence on changes in the RLGS spots. The disease-free survival rate for patients with > or =16 changed RLGS spots was significantly lower than that for patients with fewer changed RLGS spots (< or =15 spots) (P<0.001). In multivariate analysis, the number of changed spots was proven to retain an independent prognostic value (relative risk 1.095: P = 0.0031). These results suggest that the number of changed RLGS spots may be a useful biological marker for recurrence of HCC.  (+info)

Model of blood-brain transfer of oxygen explains nonlinear flow-metabolism coupling during stimulation of visual cortex. (23/1051)

The coupling between cerebral metabolic rate of oxygen (CMRO2) and blood flow (CBF) in response to visual stimulation was evaluated by means of a model of oxygen delivery. The model predicted a nonlinear relationship between stimulus-evoked changes of oxygen consumption and blood flow. The magnitude of the CMRO2/CBF ratio index (IO2) was used to indicate the degree of flow-metabolism coupling prevailing in specific areas of the brain during physiological stimulation. Therefore, the index provided a measure of the blood oxygenation level dependent (BOLD) magnetic resonance contrast. To evaluate the changes of IO2 in response to visual stimulation, the model was applied to the effect of a changing flicker rate of a visual stimulus on the magnitudes of CBF, CMRO2, and oxygen diffusion capacity, in the human brain. Positron emission tomography (PET) was used to measure the CBF and the CMRO2 in 12 healthy volunteers who viewed a cross-hair (baseline) or a yellow-blue annular checkerboard reversing at frequencies of 1, 4, or 8 Hz. The magnitude of CBF in the primary visual cortex increased as a function of the checkerboard reversal rate and reached a maximum at the frequency of 8 Hz (z=16.0), while the magnitude of CMRO2 reached a maximum at 4 Hz (z=4.0). Therefore, the calculated IO2 was lower at 8 Hz than at 1 and 4 Hz, in contrast to the oxidative metabolic rate that reached its maximum at 4 Hz. The model explained the increase of oxygen consumption as the combined effect of increased blood flow and increased oxygen diffusion capacity in the region of visual activation.  (+info)

Differential gene expression by endothelial cells in distinct angiogenic states. (24/1051)

Angiogenesis is a complex process that can be regarded as a series of sequential events comprising a variety of tissue cells. The major problem when studying angiogenesis in vitro is the lack of a model system mimicking the various aspects of the process in vivo. In this study we have used two in vitro models, each representing different and distinct aspects of angiogenesis. Differentially expressed genes in the two culture forms were identified using the suppression subtractive hybridization technique to prepare subtracted cDNA libraries. This was followed by a differential hybridization screen to pick up overexpressed clones. Using comparative multiplex RT-PCR we confirmed the differential expression and showed differences up to 14-fold. We identified a broad range of genes already known to play an important role during angiogenesis like Flt1 or TIE2. Furthermore several known genes are put into the context of endothelial cell differentiation, which up to now have not been described as being relevant to angiogenesis, like NrCAM, Claudin14, BMP-6, PEA-15 and PINCH. With ADAMTS4 and hADAMTS1/METH-1 we further extended the set of matrix metalloproteases expressed and regulated by endothelial cells.  (+info)