Development of a portable 3D ultrasound imaging system for musculoskeletal tissues

3D ultrasound is a promising imaging modality for clinical diagnosis and treatment monitoring. Its cost is relatively low in comparison with CT and MRI, no intensive training and radiation protection is required for its operation, and its hardware is movable and can potentially be portable. In this study, we developed a portable freehand 3D ultrasound imaging system for the assessment of musculoskeletal body parts. A portable ultrasound scanner was used to obtain real-time B-mode ultrasound images of musculoskeletal tissues and an electromagnetic spatial sensor was fixed on the ultrasound probe to acquire the position and orientation of the images. The images were digitized with a video digitization device and displayed with its orientation and position synchronized in real-time with the data obtained by the spatial sensor. A program was developed for volume reconstruction, visualization, segmentation and measurement using Visual C++ and Visualization toolkits (VTK) software. A 2D Gaussian filter and a Median filter were implemented to improve the quality of the B-scan images collected by the portable ultrasound scanner. An improved distance-weighted grid-mapping algorithm was proposed for volume reconstruction. Temporal calibrations were conducted to correct the delay between the collections of images and spatial data. Spatial calibrations were performed using a cross-wire phantom. The system accuracy was validated by one cylinder and two cuboid phantoms made of silicone. The average errors for distance measurement in three orthogonal directions in comparison with micrometer measurement were 0.06+/-0.39, -0.27+/-0.27, and 0.33+/-0.39 mm, respectively. The average error for volume measurement was -0.18%+/-5.44% for the three phantoms. The system has been successfully used to obtain the volume images of a fetus phantom, the fingers and forearms of human subjects. For a typical volume with 126 x 103 x 109 voxels, the 3D image could be reconstructed from 258 B-scans (640 x 480 pixels) within one minute using a portable PC with Pentium IV 2.4 GHz CPU and 512 MB memories. It is believed that such a portable volume imaging system will have many applications in the assessment of musculoskeletal tissues because of its easy accessibility.

Structural genomics efforts at the Chinese Academy of Sciences and Peking University

Structural genomics efforts at the Chinese Academy of Sciences and Peking University are reported in this article. The major targets for the structural genomics project are targeted proteins expressed in human hematopoietic stem/progenitor cells, proteins related to blood diseases and other human proteins. Up to now 328 target genes have been constructed in expression vectors. Among them, more than 50% genes have been expressed in Escherichia coli, approximately 25% of the resulting proteins are soluble, and 35 proteins have been purified. Crystallization, data collection and structure determination are continuing. Experiences accumulated during this initial stage are useful for designing and applying high-throughput approaches in structural genomics.

The gene expression profiling of sporadic pheochromocytoma and novel full-length cDNAs cloning

Pheochromocytoma is a chromaffin cell neoplasm that typically causes symptoms and signs of episodic catecholamine release. Pheochromocytoma can be divided into two types: familial and sporadic. The molecular mechanisms involved in familial pheochromocytoma have been unraveled, but the detailed molecular mechanism of sporadic pheochromocytoma remains unknown. The present study thus aimed at characterization of gene expression profiling of sporadic pheochromocytoma using expressed sequence tags (ESTs), and established a preliminary catalog of genes expressed in the tumor. In total, 4115 ESTs were generated from the tumor library. The gene expression profilings of the pheochromocytoma and the normal adrenal gland were compared, and 341 genes were identified to be significantly expressed differently between the two libraries. Interestingly, 16 known genes participating in cell division or apoptosis were notably differently expressed between the tumor and the normal adrenal gland. Twenty-four novel full-length cDNAs were cloned from the tumor library and five of them were significantly up-regulated in the tumor. Some of them may be involved in the tumorigenesis of pheochromocytoma. The sequence data of ESTs and novel full-length cDNAs described in this paper have been submitted to the GeneBank library.

Gene expression in CD34(+) cells from normal bone marrow and leukemic origins

INTRODUCTION

To address the molecular regulation of hematopoiesis and the complex mechanism in leukemogenesis, we established the first catalogs of genes expressed in normal bone marrow and leukemia CD34(+) cells.

MATERIALS AND METHODS

CD34(+) cell cDNA libraries were constructed using mRNA from adult bone marrow and from a case of acute myeloid leukemia-M5 transformed from myelodysplastic syndrome (MDS-AML). Expressed sequence tags (ESTs) and full-length cDNAs were generated by sequencing and were annotated using bioinformatic tools.

RESULTS

From a total of 4142 ESTs obtained from normal bone marrow, 3424 meaningful tags were integrated into 1630 clusters, representing 622 known genes, 522 dbEST entries and 486 novel sequences. Out of 5382 ESTs from MDS-AML, 1985 clusters were produced based on the analysis of 4321 useful ESTs, including 711 known genes, 657 known ESTs and 617 novel sequences. Among 251 transcripts found in both bone marrow and MDS-AML EST datasets and those present in only one dataset, 58 showed statistically significant differences in EST copy numbers between the two tissues (P<0.05). Twenty putative full-length cDNAs for novel genes were also cloned from the MDS-AML library.

CONCLUSION

The distinct gene expression patterns in MDS-AML-CD34(+) cells as compared to normal control cells may contribute to the development and/or maintenance of the malignant phenotypes of leukemia cells.

Insight into hepatocellular carcinogenesis at transcriptome level by comparing gene expression profiles of hepatocellular carcinoma with those of corresponding noncancerous liver

Human hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. In this work, we report on a comprehensive characterization of gene expression profiles of hepatitis B virus-positive HCC through the generation of a large set of 5'-read expressed sequence tag (EST) clusters (11,065 in total) from HCC and noncancerous liver samples, which then were applied to a cDNA microarray system containing 12,393 genes/ESTs and to comparison with a public database. The commercial cDNA microarray, which contains 1,176 known genes related to oncogenesis, was used also for profiling gene expression. Integrated data from the above approaches identified 2,253 genes/ESTs as candidates with differential expression. A number of genes related to oncogenesis and hepatic function/differentiation were selected for further semiquantitative reverse transcriptase-PCR analysis in 29 paired HCC/noncancerous liver samples. Many genes involved in cell cycle regulation such as cyclins, cyclin-dependent kinases, and cell cycle negative regulators were deregulated in most patients with HCC. Aberrant expression of the Wnt-beta-catenin pathway and enzymes for DNA replication also could contribute to the pathogenesis of HCC. The alteration of transcription levels was noted in a large number of genes implicated in metabolism, whereas a profile change of others might represent a status of dedifferentiation of the malignant hepatocytes, both considered as potential markers of diagnostic value. Notably, the altered transcriptome profiles in HCC could be correlated to a number of chromosome regions with amplification or loss of heterozygosity, providing one of the underlying causes of the transcription anomaly of HCC.

Lineage restriction of the RARalpha gene expression in myeloid differentiation

To better understand the role of retinoids in myelopoiesis, expression of the retinoid receptor genes (retinoic acid receptors [RARs] and retinoid X receptors [RXRs]) were examined during differentiation of factor-dependent cell-Paterson (FDCP)-mixA4 murine progenitor cells. The major receptor expressed in undifferentiated A4 cells was RARalpha (primarily the RARalpha1 isoform). Following induction of myelomonocytic differentiation with granulocyte and granulocyte-macrophage colony-stimulating factors, a dramatic increase in RARalpha expression (particularly the RARalpha2 isoform) was seen. In contrast, expression of both RARalpha isoforms was rapidly extinguished upon induction of erythroid differentiation with erythropoeitin (EPO). A modest induction of RXRalpha expression was seen, particularly during differentiation in the myelomonocytic lineage. Low expression levels of RARgamma2 and RXRbeta remained unchanged, irrespective of differentiation pathway. Consistent with the gene expression patterns, RARalpha agonists and antagonists stimulated myelomonocytic and erythroid differentiation of FDCP-mixA4 cells, respectively. Taken together, these results suggest that erythropoiesis and granulopoiesis require diminished and enhanced RARalpha activities, respectively, which at physiological all-trans-retinoic acid (RA) concentrations may be accomplished by reciprocal effects of EPO and myelomonocytic growth factors on its expression. This hypothesis is corroborated by data showing that RA, which positively regulates RARalpha2 expression, can exert inhibitory effects on erythroid differentiation.

Cloning and functional analysis of cDNAs with open reading frames for 300 previously undefined genes expressed in CD34+ hematopoietic stem/progenitor cells

Three hundred cDNAs containing putatively entire open reading frames (ORFs) for previously undefined genes were obtained from CD34+ hematopoietic stem/progenitor cells (HSPCs), based on EST cataloging, clone sequencing, in silico cloning, and rapid amplification of cDNA ends (RACE). The cDNA sizes ranged from 360 to 3496 bp and their ORFs coded for peptides of 58-752 amino acids. Public database search indicated that 225 cDNAs exhibited sequence similarities to genes identified across a variety of species. Homology analysis led to the recognition of 50 basic structural motifs/domains among these cDNAs. Genomic exon-intron organization could be established in 243 genes by integration of cDNA data with genome sequence information. Interestingly, a new gene named as HSPC070 on 3p was found to share a sequence of 105bp in 3' UTR with RAF gene in reversed transcription orientation. Chromosomal localizations were obtained using electronic mapping for 192 genes and with radiation hybrid (RH) for 38 genes. Macroarray technique was applied to screen the gene expression patterns in five hematopoietic cell lines (NB4, HL60, U937, K562, and Jurkat) and a number of genes with differential expression were found. The resource work has provided a wide range of information useful not only for expression genomics and annotation of genomic DNA sequence, but also for further research on the function of genes involved in hematopoietic development and differentiation.

Gene expression profiling in the human hypothalamus-pituitary-adrenal axis and full-length cDNA cloning

The primary neuroendocrine interface, hypothalamus and pituitary, together with adrenals, constitute the major axis responsible for the maintenance of homeostasis and the response to the perturbations in the environment. The gene expression profiling in the human hypothalamus-pituitary-adrenal axis was catalogued by generating a large amount of expressed sequence tags (ESTs), followed by bioinformatics analysis (http://www.chgc.sh.cn/ database). Totally, 25,973 sequences of good quality were obtained from 31,130 clones (83.4%) from cDNA libraries of the hypothalamus, pituitary, and adrenal glands. After eliminating 5,347 sequences corresponding to repetitive elements and mtDNA, 20,626 ESTs could be assembled into 9, 175 clusters (3,979, 3,074, and 4,116 clusters in hypothalamus, pituitary, and adrenal glands, respectively) when overlapping ESTs were integrated. Of these clusters, 2,777 (30.3%) corresponded to known genes, 4,165 (44.8%) to dbESTs, and 2,233 (24.3%) to novel ESTs. The gene expression profiles reflected well the functional characteristics of the three levels in the hypothalamus-pituitary-adrenal axis, because most of the 20 genes with highest expression showed statistical difference in terms of tissue distribution, including a group of tissue-specific functional markers. Meanwhile, some findings were made with regard to the physiology of the axis, and 200 full-length cDNAs of novel genes were cloned and sequenced. All of these data may contribute to the understanding of the neuroendocrine regulation of human life.

alpha-Melanocyte-stimulating hormone is contained in nerve terminals innervating thyrotropin-releasing hormone-synthesizing neurons in the hypothalamic paraventricular nucleus and prevents fasting-induced suppression of prothyrotropin-releasing hormone gene expression

The hypothalamic arcuate nucleus has an essential role in mediating the homeostatic responses of the thyroid axis to fasting by altering the sensitivity of prothyrotropin-releasing hormone (pro-TRH) gene expression in the paraventricular nucleus (PVN) to feedback regulation by thyroid hormone. Because agouti-related protein (AGRP), a leptin-regulated, arcuate nucleus-derived peptide with alpha-MSH antagonist activity, is contained in axon terminals that terminate on TRH neurons in the PVN, we raised the possibility that alpha-MSH may also participate in the mechanism by which leptin influences pro-TRH gene expression. By double-labeling immunocytochemistry, alpha-MSH-IR axon varicosities were juxtaposed to approximately 70% of pro-TRH neurons in the anterior and periventricular parvocellular subdivisions of the PVN and to 34% of pro-TRH neurons in the medial parvocellular subdivision, establishing synaptic contacts both on the cell soma and dendrites. All pro-TRH neurons receiving contacts by alpha-MSH-containing fibers also were innervated by axons containing AGRP. The intracerebroventricular infusion of 300 ng of alpha-MSH every 6 hr for 3 d prevented fasting-induced suppression of pro-TRH in the PVN but had no effect on AGRP mRNA in the arcuate nucleus. alpha-MSH also increased circulating levels of free thyroxine (T4) 2.5-fold over the levels in fasted controls, but free T4 did not reach the levels in fed controls. These data suggest that alpha-MSH has an important role in the activation of pro-TRH gene expression in hypophysiotropic neurons via either a mono- and/or multisynaptic pathway to the PVN, but factors in addition to alpha-MSH also contribute to the mechanism by which leptin administration restores thyroid hormone levels to normal in fasted animals.

The impact of differential binding of wild-type RARalpha, PML-, PLZF- and NPM-RARalpha fusion proteins towards transcriptional co-activator, RIP-140, on retinoic acid responses in acute promyelocytic leukemia

Retinoic acid receptor (RA) heterodimer (RAR/RXR) activities have been shown to be repressed by transcriptional co-repressor, SMRT/N-CoR, in the absence of the ligand while upon all-trans retionic acid (ATRA) treatment, SMRT/N-CoR is dissociated from RARalpha leading to gene expression by the recruitment of transcriptional co-activators to the transcriptional complex. The difference in response to ATRA therapy between acute promyelocytic leukemia (APL) patients with PML-RARalpha fusion and PLZF-RARalpha fusion has recently been found to be partially due to the strong association of the transcriptional co-repressor, SMRT/N-CoR, with PLZF domain. We demonstrate that SMRT association, as with PML-RARalpha, can be released from NPM-RARalpha at pharmacological concentration of ATRA (10-6 M). Moreover, we show for the first time that the interaction between the transcriptional co-activator, RIP-140, and PML-, PLZF- or NPM-RARalpha fusion proteins can be positively stimulated by ATRA although they are less sensitive as compared with the wild-type RARalpha. Our results suggest that the dissociation of transcriptional co-repressors, SMRT/N-CoR, and recruitment of co-activators, eg RIP-140, to APL-associated fusion proteins constitute a common molecular mechanism in APL and underlie the responsiveness of the disease to RA therapy. Leukemia (2000) 14, 77-83.

Distinct leukemia phenotypes in transgenic mice and different corepressor interactions generated by promyelocytic leukemia variant fusion genes PLZF-RARalpha and NPM-RARalpha

Acute promyelocytic leukemia (APL) is characterized by a specific chromosome translocation involving RARalpha and one of four fusion partners: PML, PLZF, NPM, and NuMA genes. To study the leukemogenic potential of the fusion genes in vivo, we generated transgenic mice with PLZF-RARalpha and NPM-RARalpha. PLZF-RARalpha transgenic animals developed chronic myeloid leukemia-like phenotypes at an early stage of life (within 3 months in five of six mice), whereas three NPM-RARalpha transgenic mice showed a spectrum of phenotypes from typical APL to chronic myeloid leukemia relatively late in life (from 12 to 15 months). In contrast to bone marrow cells from PLZF-RARalpha transgenic mice, those from NPM-RARalpha transgenic mice could be induced to differentiate by all-trans-retinoic acid (ATRA). We also studied RARE binding properties and interactions between nuclear corepressor SMRT and various fusion proteins in response to ATRA. Dissociation of SMRT from different receptors was observed at ATRA concentrations of 0.01 microM, 0.1 microM, and 1.0 microM for RARalpha-RXRalpha, NPM-RARalpha, and PML-RARalpha, respectively, but not observed for PLZF-RARalpha even in the presence of 10 microM ATRA. We also determined the expression of the tissue factor gene in transgenic mice, which was detected only in bone marrow cells of mice expressing the fusion genes. These data clearly establish the leukemogenic role of PLZF-RARalpha and NPM-RARalpha and the importance of fusion receptor/corepressor interactions in the pathogenesis as well as in determining different clinical phenotypes of APL.

Ventricular excitation maps using tissue Doppler acceleration imaging: potential clinical application

OBJECTIVES

The purpose of this study is to validate the use of tissue Doppler acceleration imaging (TDAI) for evaluation of the onset of ventricular contraction in humans.

BACKGROUND

Tissue Doppler acceleration imaging can display the distribution, direction and value of ventricular acceleration responses to myocardial contraction and electrical excitation.

METHODS

Twenty normal volunteers underwent TDAI testing to determine the normal onset of ventricular acceleration. Two patients with paroxysmal supraventricular tachycardia and 30 patients with permanent pacemakers underwent introduction of esophageal and right ventricular pacing electrodes, respectively, and were studied to visualize the onset of pacer-induced ventricular acceleration. Eight patients with dual atrioventricular (AV) node and 20 patients with Wolff-Parkinson-White (WPW) syndrome underwent TDAI testing to localize the abnormal onset of ventricular acceleration, and the results were compared with those of intracardiac electrophysiology (ICEP) tests.

RESULTS

The normal onset and the onset of dual AV node were localized at the upper interventricular septum (IVS) under the right coronary cusp within 25 ms before the beginning of the R wave in the electrocardiogram (ECG). In all patients in the pacing group, the location and timing of the onset conformed to the positions and timing of electrodes (100%). In patients with WPW syndrome, abnormal onset was localized to portions of the ventricular wall other than the upper IVS at the delta wave or within 25 ms after the delta wave in the ECG. The agreement was 90% (18 of 20) between the abnormal onset and the position of the accessory pathways determined by ICEP testing.

CONCLUSIONS

These results suggest that TDAI is a useful noninvasive method that frequently is successful in visualizing the intramural site of origin of ventricular mechanical contraction.

Role of central melanocortins in endotoxin-induced anorexia

Inflammation and microbial infection produce symptoms, including fever, anorexia, and hypoactivity, that are thought to be mediated by endogenous proinflammatory cytokines. Melanocortins are known to act centrally to suppress effects on fever and other sequelae of proinflammatory cytokine actions in the central nervous system, but the roles of melanocortins in anorexia and hypoactivity occurring during the acute phase response are unknown. The present study was designed to determine the effects of exogenous and endogenous alpha-melanocyte stimulating hormone (alpha-MSH) on lipopolysaccharide (LPS)-induced anorexia in relation to their effects on fever. Rats were fasted overnight to promote feeding behavior, then injected intraperitoneally with LPS (100 micrograms/kg ip), followed 30 min later by intracerebroventricular injection of either alpha-MSH or the melanocortin receptor subtype 3/subtype 4 (MC3-R/MC4-R) antagonist SHU-9119. Food intake, locomotor activity, and body temperature (Tb) were monitored during the ensuing 24-h period. Each of two intracerebroventricular doses of alpha-MSH (30 and 300 ng) potentiated the suppressive effects of LPS on food intake and locomotion, despite the fact that the higher dose alleviated LPS-induced fever. In control rats that were not treated with LPS, only the higher dose of alpha-MSH significantly inhibited food intake, and Tb and locomotor activity were unaffected. To assess the roles of endogenous central melanocortins, LPS-treated rats received intracerebroventricular SHU-9119 (200 ng). Central MC3-R/MC4-R blockade did not affect Tb or food intake in the absence of LPS treatment, but it reversed the LPS-induced reduction in 24-h food intake and increased LPS-induced fever without altering the LPS-induced suppression of locomotion. Taken together, the results suggest that exogenous and endogenous melanocortins acting centrally exert divergent influences on different aspects of the acute phase response, suppressing LPS-induced fever but contributing to LPS-induced anorexia and hypoactivity.

Novel BTB/POZ domain zinc-finger protein, LRF, is a potential target of the LAZ-3/BCL-6 oncogene

BTB/POZ-domain C2H2 zinc(Zn)-finger proteins are encoded by a subfamily of genes related to the Drosophila gap gene krüppel. To date, two such proteins, PLZF and LAZ-3/BCL-6, have been implicated in oncogenesis. We have now identified a new member of this gene subfamily which encodes a 62 kDa Zn-finger protein, termed LRF, with a BTB/POZ domain highly similar to that of PLZF. Both human and mouse LRF genes, which localized to syntenic chromosomal regions (19p13.3 and 10B5.3, respectively), were widely expressed in adult tissues and cell lines. At approximately 9.5-10.0 days of embryonic development, the mouse LRF gene was expressed in the limb buds, pharyngeal arches, tail bud, placenta and neural tube. The LRF protein associated in vivo with LAZ-3/BCL-6, but not with PLZF to which it was more related. Although the LRF, or LAZ-3/BCL-6, BTB/POZ domain could readily homodimerize, no heterodimerization was detected in vivo between the LRF and LAZ-3/BCL-6 BTB/POZ domains and interaction between full length LRF and LAZ-3/BCL-6 required the presence of both the BTB/POZ domain and Zn-fingers in each partner protein. As expected from the above results, LRF and LAZ-3/BCL-6 also colocalized with each other in the nucleus. Taken together, our findings suggest that BTB/ POZ-domain Zn-finger proteins may function as homo and heterodimeric complexes whose formation, and hence the resultant effect on transcription of their downstream target genes, is determined by the levels and expression domains of a given partner protein.

Components of a calmodulin-dependent protein kinase cascade. Molecular cloning, functional characterization and cellular localization of Ca2+/calmodulin-dependent protein kinase kinase beta

Ca2+/calmodulin-dependent protein kinases I and IV (CaMKI and CaMKIV, respectively) require phosphorylation on an equivalent single Thr in the activation loop of subdomain VIII for maximal activity. Two distinct CaMKI/IV kinases, CaMKKalpha and CaMKKbeta, were purified from rat brain and partially sequenced (Edelman, A. M., Mitchelhill, K., Selbert, M. A., Anderson, K. A., Hook, S. S., Stapleton, D., Goldstein, E. G., Means, A. R., and Kemp, B. E. (1996) J. Biol. Chem. 271, 10806-10810). We report here the cloning and sequencing of cDNAs for human and rat CaMKKbeta, tissue and regional brain localization of CaMKKbeta protein, and mRNA and functional characterization of recombinant CaMKKbeta in vitro and in Jurkat T cells. The sequences of human and rat CaMKKbeta demonstrate 65% identity and 80% similarity with CaMKKalpha and 30-40% identity with CaMKI and CaMKIV themselves. CaMKKbeta is broadly distributed among rat tissues with highest levels in CaMKIV-expressing tissues such as brain, thymus, spleen, and testis. In brain, CaMKKbeta tracks more closely with CaMKIV than does CaMKKalpha. Bacterially expressed CaMKKbeta undergoes intramolecular autophosphorylation, is regulated by Ca2+/CaM, and phosphorylates CaMKI and CaMKIV on Thr177 and Thr200, respectively. CaMKKbeta activates both CaMKI and CaMKIV when coexpressed in Jurkat T cells as judged by phosphorylated cAMP response element-binding protein-dependent reporter gene expression. CaMKKbeta activity is enhanced by elevation of intracellular Ca2+, although substantial activity is observed at the resting Ca2+ concentration. The strict Ca2+ requirement of CaMKIV-dependent phosphorylation of cAMP response element-binding protein, is therefore controlled at the level of CaMKIV rather than CaMKK.

Systemic alpha-MSH suppresses LPS fever via central melanocortin receptors independently of its suppression of corticosterone and IL-6 release

Systemically administered alpha-melanocyte-stimulating hormone (alpha-MSH) inhibits endotoxin (lipopolysaccharide; LPS)- or interleukin (IL)-1-induced fever and adrenocortical activation, but the sites of these actions and the mechanisms involved are unknown. The aims of this study were, first, to determine whether melanocortin receptors (MCR) located within the central nervous system mediate the suppressive effects of peripherally administered alpha-MSH on LPS-induced fever and activation of the pituitary-adrenal axis and, second, to determine whether systemic alpha-MSH suppresses the LPS-induced rise in plasma IL-6 levels, potentially contributing to its antipyretic effect. Male rats received Escherichia coli LPS (25 microg/kg ip). Core body temperatures (Tb) were determined hourly by radiotelemetry (0-8 h), and blood was withdrawn via venous catheters for plasma hormone immunoassays (0-2 h) and IL-6 bioassay (0-8 h). alpha-MSH (100 microg/kg ip) completely prevented the onset of LPS-induced fever during the first 3-4 h after LPS and suppressed fever throughout the next 4 h but did not affect Tb in afebrile rats treated with intraperitoneal saline rather than LPS. Intraperitoneal alpha-MSH also suppressed the LPS-induced rise in plasma IL-6, ACTH, and corticosterone (CS) levels. Intracerebroventricular injection of SHU-9119, a potent melanocortin-4 receptor (MC4-R)/MC3-R antagonist, completely blocked the antipyretic effect of intraperitoneal alpha-MSH during the first 4 h after LPS but had no effect on alpha-MSH-induced suppression of LPS-stimulated plasma IL-6 and CS levels. Taken together, the results indicate that the antipyretic effect of peripherally administered alpha-MSH during the early phase of fever is mediated by MCR within the brain. In contrast, the inhibition of LPS-induced increases in plasma CS and IL-6 levels by intraperitoneal alpha-MSH appears to be mediated by a different mechanism(s), and these effects do not contribute to its antipyretic action.

Identification of genes expressed in human CD34(+) hematopoietic stem/progenitor cells by expressed sequence tags and efficient full-length cDNA cloning

Hematopoietic stem/progenitor cells (HSPCs) possess the potentials of self-renewal, proliferation, and differentiation toward different lineages of blood cells. These cells not only play a primordial role in hematopoietic development but also have important clinical application. Characterization of the gene expression profile in CD34(+) HSPCs may lead to a better understanding of the regulation of normal and pathological hematopoiesis. In the present work, genes expressed in human umbilical cord blood CD34(+) cells were catalogued by partially sequencing a large amount of cDNA clones [or expressed sequence tags (ESTs)] and analyzing these sequences with the tools of bioinformatics. Among 9,866 ESTs thus obtained, 4,697 (47.6%) showed identity to known genes in the GenBank database, 2, 603 (26.4%) matched to the ESTs previously deposited in a public domain database, 1,415 (14.3%) were previously undescribed ESTs, and the remaining 1,151 (11.7%) were mitochondrial DNA, ribosomal RNA, or repetitive (Alu or L1) sequences. Integration of ESTs of known genes generated a profile including 855 genes that could be divided into different categories according to their functions. Some (8.2%) of the genes in this profile were considered related to early hematopoiesis. The possible function of ESTs corresponding to so far unknown genes were approached by means of homology and functional motif searches. Moreover, attempts were made to generate libraries enriched for full-length cDNAs, to better explore the genes in HSPCs. Nearly 60% of the cDNA clones of mRNA under 2 kb in our libraries had 5' ends upstream of the first ATG codon of the ORF. With this satisfactory result, we have developed an efficient working system that allowed fast sequencing of 32 full-length cDNAs, 16 of them being mapped to the chromosomes with radiation hybrid panels. This work may lay a basis for the further research on the molecular network of hematopoietic regulation.

Central noradrenergic system modulates plasma interleukin-6 production by peripheral interleukin-1

The role of the central noradrenergic system in systemic interleukin-6 (IL-6) production induced by intravenously administered recombinant human interleukin-1 beta (IL-1 beta) was examined in rats. Pretreatment of rats intracerebroventricularly with 6-hydroxydopamine (6-OHDA, 100 or 200 micrograms/rat) significantly attenuated the increase in plasma IL-6 levels caused by IL-1 beta (2 micrograms/kg i.v.). A modest inhibition of the IL-1 beta-induced plasma IL-6 production was observed following pretreatment with prazosin (20 micrograms/rat i.c.v.) but not after administration of idazoxan or propranolol. There were no significant increases in the IL-6 content in the hypothalamus, medulla oblongata, and cortex of the brain after intravenous IL-1 beta. Adrenalectomy produced an augmented plasma IL-6 response to intravenous IL-1 beta, whereas chemical sympathectomy with intraperitoneal injection of 6-OHDA (50 or 100 mg/kg) decreased the IL-1 beta-induced plasma IL-6 levels. Nor-epinephrine (NE), in the dose range 10(-6)-10(-4) M, significantly increased the IL-6 levels in the rat spleen lymphocyte culture media. At doses of 10(-9)-10(-7) M, NE enhanced the effect of IL-1 beta on the IL-6 release by spleen lymphocytes in a dose-dependent manner. These findings suggest that the plasma IL-6 response to intravenous IL-1 beta is partially mediated through the activation of the central noradrenergic system and a consequent increase in the sympathetic outflow to the peripheral tissues and that the NE released from the sympathetic terminals may function as a mediator and/or modulator to facilitate the synthesis/release of IL-6 in the sympathetic nerve-innervated organs.

Antipyretic role of endogenous melanocortins mediated by central melanocortin receptors during endotoxin-induced fever

Bacterial infection causes fever, an adaptive but potentially self-destructive response, in the host. Also activated are counterregulatory systems such as the pituitary-adrenal axis. Antipyretic roles have also been postulated for certain endogenous central neuropeptides, including the melanocortins (alpha-MSH-related peptides). To test the hypothesis that endogenous central melanocortins have antipyretic effects mediated by central melanocortin receptors (MCRs), we determined the effect of intracerebroventricular injection of a synthetic MCR antagonist, Ac-Nle4,c-[Asp5,DNal(2')7,Lys10]alpha-MSH(4-10)-NH2 (SHU-9119) in endotoxin-challenged rats. The efficacy and specificity of SHU-9119 as an MCR antagonist in the rat was first validated in vitro and in vivo. In vitro, in heterologous cells expressing either rat MC3-R or MC4-R, the major MCR subtypes expressed in brain, SHU-9119 showed no intrinsic agonism, but it inhibited alpha-MSH-induced cAMP accumulation (IC50 = 0.48 +/- 0.19 and 0.41 +/- 0.28 nM, respectively) and [125I]-[Nle4,DPhe7]-alpha-MSH binding (IC50 = 1.0 +/- 0.1 and 0.9 +/- 0.3 nM, respectively). In vivo, exogenous alpha-MSH (180 pmol) inhibited fever in rats when administered intracerebroventricularly 30 min after Escherichia coli lipopolysaccharide (LPS) (25 microg/kg, i.p.). When co-injected with alpha-MSH, SHU-9119 (168 pmol, i.c.v.) prevented the antipyretic action of exogenous alpha-MSH. In contrast, neither alpha-MSH nor SHU-9119, alone or in combination, affected body temperatures in afebrile rats. In LPS-treated rats, intracerebroventricular injection of SHU-9119 significantly increased fever, whereas intravenous injection of the same dose of SHU-9119 had no effect. Neither intracerebroventricular nor intravenous SHU-9119 significantly affected LPS-stimulated plasma ACTH or corticosterone levels. The results indicate that endogenous central melanocortins exert an antipyretic influence during fever by acting on MCRs located within the brain, independent of any modulation of the activity of the pituitary-adrenal axis.

EEN encodes for a member of a new family of proteins containing an Src homology 3 domain and is the third gene located on chromosome 19p13 that fuses to MLL in human leukemia

The MLL gene, the closest human homologue to the Drosophila trithorax gene, undergoes chromosomal translocation with a large number of different partner genes in both acute lymphoid and acute myeloid leukemias. We have identified a new partner gene, EEN, fused to MLL in a case of acute myeloid leukemia. The gene is located on chromosome 19p13, where two other MLL partner genes, ENL and ELL/MEN have also been identified. The deduced protein of 368 aa contains a central alpha-helical region and a C-terminal Src homology 3 (SH3) domain most similar to the C-terminal SH3 domain found in the Grb2/Sem-5/Drk family of genes. Sequence analysis of the fusion MLL/EEN transcript in our patient reveals that exon 6 of MLL is fused to the N-terminal end of EEN, a fusion that would create a chimeric protein that includes the major functional domain of EEN. EEN is expressed in a variety of tissue types and encodes a protein of approximately 46 kDa. The EEN protein is the human homologue of a member of a recently described murine SH3 domain-containing protein family. It is also highly related to a putative gene identified in Caenorhabditis elegans, and a number of similar sequences are present in the EST databases of several species.

Neuroimmunological effects of exposure to methylmercury forms in the Sprague-Dawley rats. Activation of the hypothalamic-pituitary-adrenal axis and lymphocyte responsiveness

The effects of different methylmercury (MeHg) forms on the immune system and the hypothalamic pituitary adrenal (HPA) axis were assessed. The lymphocyte response to Concanavalin A (Con A) stimulation, blood levels of interleukin-6 (IL-6), adrenocorticotrophin hormone (ACTH), and corticosterone in the presence of different MeHg compounds was measured. Rats were exposed to methylmercury sulfide [(MeHg)2S] and methylmercury chloride (MeHgCl) at concentrations of 5 and 500 micrograms per liter in the drinking water for 8 or 16 weeks. Short-term exposure (8 weeks) at both, low- and high-doses of (MeHg)2S significantly enhanced lymphocyte responsiveness. MeHgCl only induced increased lymphocyte responsiveness at the low-dose exposure. Circulating levels of IL-6 after short-term exposure were increased in the MeHgCl-exposed group. The HPA axis activation was demonstrated by increased levels of ACTH and corticosterone levels. This response was predominant in low-dose exposed animals. Long-term (16 weeks) exposure resulted in a reduction in lymphocyte prolife ration after both low- and high-dose MeHgCl exposures. The (MeHg)2S exposure resulted in a 3-fold increase in the proliferative response. Levels of ACTH were elevated 3-fold in the (MeHg)2S-exposed group and no increase of corticosterone was observed in the high-dose exposed group at 8 weeks, no effect of (MeHg)2S was observed at 16 weeks. The MeHgCl exposed group showed an increase in ACTH and corticosterone levels at 8 weeks; this response was not observed at 16 weeks. These data indicate that exposure to MeHg compounds enhances T-cell proliferation in most of the cases, in a dose- and time-dependent fashion. Release of IL-6 also depends on the length of exposure. Early increases in circulating ACTH at 8 weeks also suggest activation of the HPA axis. This may contribute to the production of IL-6 and surveillance of regulatory homeostatic responses against environmental agents that mimic stress-like responses.

RIG-E, a human homolog of the murine Ly-6 family, is induced by retinoic acid during the differentiation of acute promyelocytic leukemia cell

In vivo all-trans-retinoic acid (ATRA), a differentiation inducer, is capable of causing clinical remission in about 90% of patients with acute promyelocytic leukemia (APL). The molecular basis for the differentiation of APL cells after treatment with ATRA remains obscure and may involve genes other than the known retinoid nuclear transcription factors. We report here the ATRA-induced gene expression in a cell line (NB4) derived from a patient with APL. By differential display-PCR, we isolated and characterized a novel gene (RIG-E) whose expression is up-regulated by ATRA. The gene is 4.0 kb long, consisting of four exons and three introns, and is localized on human chromosome region 8q24. The deduced amino acid sequence predicts a cell surface protein containing 20 amino acids at the N-terminal end corresponding to a signal peptide and an extracellular sequence containing 111 amino acids. The RIG-E coded protein shares some homology with CD59 and with a number of growth factor receptors. It shares high sequence homology with the murine LY-6 multigene family, whose members are small cysteine-rich proteins differentially expressed in several hematopoietic cell lines and appear to function in signal transduction. It seems that so far RIG-E is the closest human homolog of the LY-6 family. Expression of RIG-E is not restricted to myeloid differentiation, because it is also present in thymocytes and in a number of other tissues at different levels.

Long-term follow-up of minimal residual disease in childhood acute lymphoblastic leukemia patients by polymerase chain reaction analysis of multiple clone-specific or malignancy-specific gene markers

Two types of markers, namely the clone-specific markers including T-cell receptor (TCR) gamma, TCR delta, and Ig heavy-chain (IgH) gene rearrangements, and malignancy-specific fusion gene mRNA such as SIL-TAL-1, BCR-ABL, and HRX-partner genes, were investigated by molecular biology techniques in 65 Chinese patients with acute lymphoblastic leukemia (ALL). In combination, these markers were informative among 96% of patients. Minimal residual disease (MRD) was followed up in 23 of these patients with available materials over a period varying from 8 to 54 months with at least one leukemia-specific probe. In most children, MRD was decreased continuously to an ultimately undetectable level within 6 to 12 months after remission induction therapy. One patient exhibited low-level residual leukemic cells for 4 years before the MRD turned negative. Another patient remained in complete remission for 45 months, although a positive signal was detected at 34 months using TCR delta probe, but was negative with a TCR gamma marker which was positive at presentation. In three patients who relapsed, MRD either persisted through the clinical course or became positive and eventually increased 3-11 months before clinical relapse. These data suggested that the combined use of multiple gene markers is a valuable tool for the PCR-based MRD detection, since it can cover most ALL patients. Furthermore, long-term follow-up of MRD is helpful for determining the dosage as well as the period of maintenance chemotherapy and for predicting impending relapse.

Phosphorylation and activation of Ca(2+)-calmodulin-dependent protein kinase IV by Ca(2+)-calmodulin-dependent protein kinase Ia kinase. Phosphorylation of threonine 196 is essential for activation

Purified pig brain Ca(2+)-calmodulin (CaM)-dependent protein kinase Ia kinase (Lee, J. C., and Edelman, A. M. (1994) J. Biol. Chem. 269, 2158-2164) enhances, by up to 24-fold, the activity of recombinant CaM kinase IV in a reaction also requiring Ca(2+)-CaM and MgATP. The addition of brain extract, although capable of activating CaM kinase IV by itself, provides no further activation beyond that induced by purified CaM kinase Ia kinase, consistent with the lack of a requirement of additional components for activation. Activation is accompanied by the development of significant (38%) Ca(2+)-CaM-independent CaM kinase IV activity. In parallel fashion to its activation, CaM kinase IV is phosphorylated in a CaM kinase Ia kinase-, Ca(2+)-CaM-, and MgATP-dependent manner. Phosphorylation occurs on multiple serine and threonine residues with a Ser-P:Thr-P ratio of approximately 3:1. The identical requirements for phosphorylation and activation and a linear relationship between extent of phosphorylation of CaM kinase IV and its activation state indicate that CaM kinase IV activation is induced by its phosphorylation. Replacement of Thr-196 of CaM kinase IV with a nonphosphorylatable alanine by site-directed mutagenesis abolishes both the phosphorylation and activation of CaM kinase IV, demonstrating that Thr-196 phosphorylation is essential for activation.