Improved heterologous expression of the white-rot fungal ligninase H8 by crossover linker mutagenesis

Using the crossover-linker mutagenesis method, the 5' noncoding region of the lambda ML-1 cDNA, which encodes the ligninase H8 isozyme of the white-rot fungus, Phanerochaete chrysosporium, was deleted with the simultaneous insertion of the putative Spodoptera frugiperda ribosome-binding sequence (RBS) (TATAAAT) directly in front of the translation-initiation codon of this gene. A recombinant baculovirus, pVL-Mu-H8, carrying the ligninase-H8 gene was successfully constructed, as determined by both sequence analysis and dot blot hybridization. A more than 18-fold increase in the expression of ligninase H8, compared to the previous pEV11-1A.3 recombinant baculovirus, was detected in the Sf-21 insect cells. This enzyme was detected within 3 d postinfection and was biologically active, capable of oxidizing the model lignin compound, veratryl alcohol. The molecular weight of the overexpressed 42 kD protein was similar to that of the native fungal ligninase-H8 isozyme and it also reacted specifically with the anti-H8 monoclonal antibody (MAb 2D4.9) in Western blot analysis.

Cerebral perfusion SPECT imaging in epileptic and nonepileptic seizures

Patients with epileptic and nonepileptic seizures are commonly encountered in clinical practice, and they can pose a difficult diagnostic problem. We present two cases that show the difficult task of differentiating between true epileptic and nonepileptic or psychogenic seizures in some patients. The clinical presentations were complex and the use of video-monitored EEG alone was insufficient to make definitive diagnoses. Ictal and interictal Tc-99m HMPAO brain perfusion SPECT imaging examinations were used to help establish the correct diagnoses. This report describes the advantage of using the brain perfusion SPECT imaging examination. The injection of stabilized Tc-99m HMPAO during an ictal event followed by appropriate medical therapy provides a method of obtaining a reasonable image of relative perfusion (activity) during the seizure. These images can then be compared with interictal examinations and an epileptic or nonepileptic focus may be localized. The Tc-99m HMPAO brain perfusion SPECT imaging study was helpful in establishing the correct diagnosis in both cases.

Control of mouse cardiac morphogenesis and myogenesis by transcription factor MEF2C

Members of the myocyte enhancer factor-2 (MEF2) family of MADS (MCM1, agamous, deficiens, serum response factor)-box transcription factors bind an A-T-rich DNA sequence associated with muscle-specific genes. The murine MEF2C gene is expressed in heart precursor cells before formation of the linear heart tube. In mice homozygous for a null mutation of MEF2C, the heart tube did not undergo looping morphogenesis, the future right ventricle did not form, and a subset of cardiac muscle genes was not expressed. The absence of the right ventricular region of the mutant heart correlated with down-regulation of the dHAND gene, which encodes a basic helix-loop-helix transcription factor required for cardiac morphogenesis. Thus, MEF2C is an essential regulator of cardiac myogenesis and right ventricular development.

Involvement of protein kinase C in responses of rat dorsal horn neurons to mechanical stimuli and periaqueductal gray descending inhibition

The effects of a protein kinase C (PKC) activator, 12-O-tetradecanoylphorbol-13-acetate (TPA), on the activity and periaqueductal gray (PAG)-induced inhibition of rat dorsal horn neurons of the lumbar spinal cord were tested. A microdialysis fiber was placed through the dorsal horn for the purpose of local application of pharmacological agents. Extracellular single-unit recordings from dorsal horn neurons were made near the microdialysis fiber. TPA was tested on nociceptive dorsal horn cells. There was a significant increase in the background activity and responses to "brush", with no changes in responses to pressure and pinch stimuli. TPA also significantly blocked the PAG-induced inhibition of responses to brush, press, and pinch. These effects were eliminated by coadministration of the PKC inhibitor NPC-15437. The solvent, which contained dimethyl sulfoxide, was also tested for its effect on the responses to peripheral mechanical stimuli and PAG-induced inhibition of the dorsal horn neurons. There were no significant changes. This experiment suggests that activation of the PKC second messenger system might increase the activity of dorsal horn neurons and their responses to peripheral stimuli; in addition, the phorbol ester attenuated the PAG-induced descending inhibition of the dorsal horn neuron activity.

Involvement of cGMP in nociceptive processing by and sensitization of spinothalamic neurons in primates

Central sensitization of spinothalamic tract (STT) neurons in anesthetized monkeys after intradermal injection of capsaicin depends in part on disinhibition. Protein kinase C is suggested to participate in this process. The present study shows that the nitric oxide-cGMP (NO-cGMP) signal transduction system also contributes to sensitization of wide dynamic range (WDR) STT neurons located in the deep dorsal horn. The NO-cGMP system was activated by microdialysis administration into the dorsal horn of 8-bromo-cGMP, an analog of cGMP. Sensitization of STT cells by 8-bromo-cGMP increased the responses of deep WDR STT cells to both weak and strong mechanical stimulation of the skin and simultaneously attenuated the inhibition of the same neurons produced by stimulation in the periaqueductal gray (PAG). In contrast, WDR STT cells in the superficial dorsal horn and high-threshold (HT) STT cells in superficial or deep layers showed reduced responses to mechanical stimulation of the skin after infusion of 8-bromo-cGMP, and PAG inhibition of these neurons was unaffected. Sensitization of STT cells and the attenuation of PAG inhibition induced by intradermal injection of capsaicin were prevented by preteatment of the dorsal horn with a guanylate cyclase inhibitor, 1 H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one. The results support the hypothesis that activation of the NO-cGMP signal transduction system contributes to the sensitization of WDR STT neurons in the deep dorsal horn and helps explain why intradermal capsaicin injections often fail to sensitize superficial and HT STT cells. The results also support the idea that sensitization of STT cells is produced in part by disinhibition.

Requirement of the transcription factor GATA4 for heart tube formation and ventral morphogenesis

The zinc finger transcription factor GATA4 has been implicated in heart development based on its early expression in precardiogenic splanchnic mesoderm and its ability to activate the expression of a number of cardiac-specific genes. To determine the role of GATA4 in embryogenesis, we generated mice homozygous for a GATA4 null allele. Homozygous GATA4 null mice arrested in development between E7.0 and E9.5 because of severe developmental abnormalities. Mutant embryos most notably lacked a primitive heart tube and foregut and developed partially outside the yolk sac. In the mutants, the two bilaterally symmetric promyocardial primordia failed to migrate ventrally but instead remained lateral and generated two independent heart tubes that contained differentiated cardiomyocytes. We show that these deformities resulted from a general loss in lateral to ventral folding throughout the embryo. GATA4 is most highly expressed within the precardiogenic splanchnic mesoderm at the posterior lip of the anterior intestinal portal, corresponding to the region of the embryo that undergoes ventral fusion. We propose that GATA4 is required for the migration or folding morphogenesis of the precardiogenic splanchnic mesodermal cells at the level of the AIP.

Interferons alpha/beta inhibit IL-7-induced proliferation of CD4- CD8- CD3- CD44+ CD25+ thymocytes, but do not inhibit that of CD4- CD8- CD3- CD44- CD25- thymocytes

Type 1 interferons (IFN-alpha/beta) have recently been shown to inhibit interleukin-7 (IL-7)-induced growth and survival of early B-lineage cells. The CD3- CD4- CD8- (triple negative; TN) thymocytes from normal mice strongly proliferated upon stimulation with IL-7 in suspension, culture. Such an IL-7-induced proliferation was suppressed by the addition of IFN-alpha/beta, but a fraction of the TN thymocytes still showed proliferation. The IL-7-induced growth of TN thymocytes from acid mice, which lack the CD44- CD25- subpopulation, was completely inhibited by the addition of IFN-alpha/beta. The IL-7 induced proliferation of CD4- CD8- thymocytes from T-cell receptor (TCR) transgenic mice, the majority of which are CD3+ CD44- CD25-, was resistant to IFN-alpha/beta-mediated suppression. In fetal thymus organ cultures (FTOC), the addition of IL-7 greatly increased the population of CD4- CD8- CD44+ CD25+ thymocytes and IFN-alpha/beta inhibited this IL-7-driven expansion. In contrast, the addition of IL-7 markedly decreased the percentages of CD4- CD8- CD3- CD44- CD25- cells, and IFN-alpha/beta reversed the effect and increased the subpopulations of CD44- CD25+ and CD44- CD25-. Finally, IFN-beta mRNA was found to be expressed in the thymus. The data suggest that type I interferons inhibit IL-7-driven proliferation of TN thymocytes, but do not block the normal differentiation process.

[Assay of terpenes in the leaves of Ginkgo biloba extract and its preparations by in situ fluorometric TLC]

A new TLC method for the assay of terpene lactones in Ginkgo biloba extract and its preparations has been established by means of optimized development condition and post-chromatographic thermal fluorescence derivatization. Satisfactory results can be obtained through polynomial regression calibration. The data obtained by this method have been proved ten times higher in sensitivity than those obtained by HPLC-refracto-detector.

[High performance gel chromatographic behaviour of sodium alginate and determination of its molecular weight parameters]

The molecular weight parameters of sodium alginate were determined by high performance gel chromatography with Waters Bondagel E-High A column. The differences in high performance gel chromatographic behaviours between the sodium alginate and the non-polar standard Dextran T500 were compared. The influences of the sample concentration and the sample volume on the results were discussed. The high performance gel chromatographic behaviour of sodium alginate is different from that of Dextran T500, and is also different from those on Sepharose or Sephadex columns. The peak shifted toward full osmotic side under in crease of ionic strength. The elution volumn didn't tend toward stable, even though at the high concentration of 0.5mol/L NaCl. A change of the sample concentration at stable sample volume or the sample volume at stable sample concentration would cause tailing peaks. It was showed that the sample size of sodium alginate would be less than 25microg, and the relative standard deviations of Mn, Mw and d were 0.95%, 4.04% and 4.70%.

Fluorescence studies on the interaction of a synthetic signal peptide and its analog with liposomes

The N-terminal signal sequence of glucitol permease of Escherichia coli (Gut22: MIETITPGAVWFIGLFQKGGEC) and its analog (Gut22Ana: MIETITHGAEWFIGLFQKGGEC) were synthesized. The analog had a Pro residue substituted for the His at the 7th position of Gut22 and a Val residue substituted for the Glu at the 10th position. Previous studies indicated that due to its structural rigidity, the interaction of Gut22Ana with lipid bilayer was much weaker than that of Gut22 (Wang, Q.D., Cui, D.F. and Lin, Q.S. (1996) Science in China (Series C) 39, 395-405). To further probe the location of the tryptophan residues of the peptides in lipid bilayer, the membrane penetration depth of the tryptophan residue of Gut22 was measured using spin-labeled phospholipids, and fluorescence quenching of the peptides by iodide and acrylamide in the presence and absence of phosphatidylserine/phosphatidylcholine liposomes were also studied. Fluorescent labeling of the peptides enabled the study of their association with membrane by fluorospectrophotometry. In the presence of liposomes, the peptides were protected from reaction with chymotrypsin, indicating that the peptide incorporated into the membrane. However, dithionite, which acts external to the membrane, reacted with the peptide, showing that the peptides did not translocate across lipid bilayer spontaneously.

Human fetal astrocytes as an ex vivo gene therapy vehicle for delivering biologically active nerve growth factor

The therapeutic use of neurotrophic factors for neurodegenerative diseases is promising, however, optimal methods for continuous delivery of these substances to the human central nervous system (CNS) remains problematic. One approach would be to graft genetically engineered human cells that continuously secrete high levels of a biologically produced and processed neurotrophic factor. This ex vivo gene therapy approach has worked well in animal models of neurodegenerative diseases using a variety of nonneuronal cell types to deliver the transgene. In our studies, we have been investigating the potential of astrocytes, a cell type normally present in the CNS, as a vehicle for ex vivo gene therapy. Here, we demonstrate that astrocytes in the human fetal cortex can be isolated and efficiently infected with an amphotropic retrovirus harboring mouse beta-nerve growth factor (NGF). These transduced astrocytes express high levels of NGF mRNA and secrete bioactive NGF protein as demonstrated by stimulation of neurite outgrowth from adrenal chromaffin cells. NGF ELISA showed that these astrocytes secrete NGF protein at a rate of 41 ng/day per 10(5) cells after 2 weeks in vitro, whereas NGF is undetectable in medium conditioned by normal astrocytes. These data suggest that human fetal astrocytes can be used for delivering biologically produced neurotrophic factors to the human CNS.

Dopaminergic neurons protected from degeneration by GDNF gene therapy

Glial cell line-derived neurotrophic factor (GDNF) supports growth and survival of dopaminergic (DA) neurons. A replication-defective adenoviral (Ad) vector encoding human GDNF injected near the rat substantia nigra was found to protect DA neurons from the progressive degeneration induced by the neurotoxin 6-hydroxydopamine (6-OHDA) injected into the striatum. Ad GDNF gene therapy reduced loss of DA neurons approximately threefold 6 weeks after 6-OHDA lesion, as compared with no treatment or injection of Ad lacZ or Ad mGDNF (encoding a biologically inactive deletion mutant GDNF). These results suggest that Ad vector-mediated GDNF gene therapy may slow the DA neuronal cell loss in humans with Parkinson's disease.

Expression and functional analysis of Euglena Gracilis chloroplast initiation factor 3

A portion of a cDNA predicted to encode the mature form of Euglena gracilis chloroplast translational initiation factor 3 (IF-3chlM, molecular mass, 46 402) and the portion of this factor homologous to bacterial IF-3 (IF-3chlH, molecular mass 22 829) have been cloned and expressed in Escherichia coli as histidine-tagged proteins. The homology domain can be expressed in reasonable levels in E. coli. However, IF-3chlM is quite toxic and can only be produced in small amounts. Both forms of the chloroplast factor are associated with E. coli ribosomes. Purification procedures have been developed for both IF-3chlM and IF-3chlH using Ni-NTA affinity chromatography followed by ion exchange chromatography. IF-3chlM and IF-3chlH are active in promoting ribosome dissociation and in promoting the binding of fMet-tRNA to E. coli ribosomes. However, IF-3chlH has at least 5-fold more activity than either native IF-3chl or IF-3chlM in promoting initiation complex formation on chloroplast 30S ribosomal subunits in the presence of a mRNA carrying a natural translational initiation signal. This observation suggests that regions of IF-3chl lying outside of the homology domain may down-regulate the activity of this factor.

Effects of GABA and glycine receptor antagonists on the activity and PAG-induced inhibition of rat dorsal horn neurons

The effects of bicuculline and strychnine on the activity and periaqueductal gray (PAG)-induced inhibition of rat dorsal horn neurons of the lumbar spinal cord were tested. Extracellular single unit recordings were from 36 dorsal horn neurons near a microdialysis fiber passed through the spinal cord for drug application. The GABAA receptor antagonist, bicuculline, was tested on 19 cells, whereas the glycine receptor antagonist, strychnine, was tested on 17 cells. Both bicuculline and strychnine increased the background activity and responses to mechanical stimulation (BRUSH, PRESS, and PINCH) of the skin.06 They also significantly blocked the PAG-induced inhibition of responses to peripheral mechanical stimuli. This experiment suggests that the mechanism of PAG-induced descending inhibition of dorsal horn neuron activity involves GABA and/or glycine release in the spinal cord and that there is tonic release of these inhibitory neurotransmitters.

[Limb-preserving segmental bone resection for malignant bone tumors of the extremities: a report of 27 cases]

Segmental bone resection with preservation of the affected limb was performed in 27 patients with malignant bone tumors. Diagnosis as confirmed by histopathology was: osteosarcoma (n = 8), chondrosarcoma (n = 3), fibrosarcoma (n = 2), malignant fibrous histiocytoma (n = 2), giant cell tumor (n = 6), reticulum cell sarcoma (n = 1), myeloma (n = 1) and metastatic bone tumor (n = 4). Four different kinds of operative procedure were used: enbloc resection of shoulder girdle in 13 cases, segmental resection and replantation of distal forearm in 1, partial hemipelvisection in 6 and segmental resection of the lower thigh with leg rotation plasty in 7. Twenty four patients were followed up from 16 months to more then 12 years. Twenty patients survived for more than 2 years, 9 patients survived over 5 years with functional limbs. The 2- and 5-year survival rate was 83.3% and 37.5%, respectively.

Inhibition of primate spinothalamic tract neurons by spinal glycine and GABA is reduced during central sensitization

1. In our previous work, we demonstrated that the glycinergic and GABAergic mechanisms that help mediate the descending inhibition from the periaqueductal gray exert a tonic modulation of nociceptive inputs through spinal glycine and gamma-aminobutyric acid (GABA) receptors. This study was designed to examine further possible changes in the inhibition of the activity of spinothalamic tract (STT) neurons mediated by spinal glycine and GABA receptors when STT cells are sensitized by intradermal injection of capsaicin, and to investigate the role of the protein kinase C (PKC) system in the functional modulation of these receptors. 2. Although the responses of STT cells to cutaneous mechanical stimuli were sensitized by intradermal injection of capsaicin, the inhibition of the responses of all STT cells tested to noxious cutaneous stimuli produced by iontophoretic release of glycine and GABA was significantly attenuated. The inhibition elicited by iontophoretic application of a GABAA agonist, muscimol, was reduced in some of the cells tested. 3. When the spinal cord dorsal horn was pretreated with a selective PKC inhibitor, 2,6-diamino-N-([1-oxotridecyl-2-piperidinyl]- methyl)hexanamide, by microdialysis, sensitization of STT cells by capsaicin injection and the accompanying attenuation of glycine- and GABA-induced inhibition were prevented. 4. Sensitization of STT cells to cutaneous mechanical stimuli was also induced by administration of the PKC activator, 12-O-tetradecanoylphorbol-13-acetate, into the spinal dorsal horn. The inhibition produced by iontophoretic release of glycine, GABA, and muscimol was found to be reduced in most cells examined when this phorbol ester was used. An inactive phorbol ester, 4 alpha-phorbol 12,13-didecanoate, did not produce significant effects on cellular activity. 5. These results suggest that there is an activation of PKC in the spinal cord when STT neurons are sensitized after intradermal injection of capsaicin or administration of phorbol ester. This sensitization is likely to be involved in the development of allodynia and secondary hyperalgesia not only by enhancing the responses of excitatory amino acid receptors but also by desensitizing glycine and GABA receptors.

Interaction of synthetic peptide corresponding to signal sequence of glucitol permease of Escherichia coli and its analogue with liposomes

The N-terminal signal sequence of glucitol permease of Escherichia Coli (Gut22) and its analogue (Gut22Ana) were synthesized. The analogue had a Pro residue substituting for the His at the 7th position of Gut22 and a Val residue substituting for the Glu at the 10th position. The intrinsic fluorescence emission spectra indicated that the binding of Gut22 with lipid bilayer was much stronger than that of Gut22Ana. The leakage experiments with calcein-loaded liposomes showed that Gut22 strongly perturbed lipid bilayers while Gut22Ana did not. The apparent partition constant of Gut22 for partitioning into phosphatidylserine/phosphatidylcholine bilayers was measured; the effect of membrane potential on the interaction of Gut22 with lipid bilayers was studied and the conformation changes of Gut22 and Gut22Ana upon interacting with liposomes were studied by the method of circular dichroism analysis.

Purification of transthyretin by high performance affinity chromatography from human plasma

The partial purification of human transthyretin (TTR) by high performance affinity chromatography with the help of other separation techniques is described in the present paper. A new affinity medium was prepared with a monosized (ca. 10 microns particle size) macroporous resin as the support and thyroxine (T4) as the ligand. The purification of TTR was carried out in a few simple steps involving serum precipitation, anion exchange, Thyroxine affinity chromatography and gel filtration. The overall yield was 29% and the refined TTR contained less than 2% impurities as analyzed by RP-HPLC. When TTR was administrated to the culture medium DMEM of liver tumor strain SMMC-7721, a true inhibition of cell growth (ca. 50%) was observed as an actual decrease in cell number over time.

Involvement of alpha-2 adrenoceptors in the periaqueductal gray-induced inhibition of dorsal horn cell activity in rats

The noradrenergic system is considered to be one of the major descending analgesia systems originating in the brainstem. The relationship between the periaqueductal gray (PAG) and the descending noradrenergic system is of great interest. A projection from the PAG to the locus ceruleus and parabrachial region has been reported. It is possible that electrical stimulation of the PAG activates spinally projecting collaterals of the noradrenergic cells in A5, the locus ceruleus, subceruleus and A7/Kölliker-Fuse nucleus. The current experiments were designed to study the role of alpha-2 adrenoceptors on spinal cord dorsal Horn cells in PAG-induced inhibition. A microdialysis fiber was introduced into the dorsal horn of the lumbar enlargement for drug administration. An electrode was placed in the vicinity of the microdialysis fiber for extracellular single-unit recording. Recordings were made from a total of 35 cells from 22 Sprague-Dawley rats (270-360 g). When the PAG was stimulated, responses to mechanical stimuli applied to the skin (brush, press and pinch) were inhibited. When an alpha-2 adrenoceptor agonist (clonidine) was administered, the background activity and the responses of the cell to brush, press and pinch stimuli were decreased. In contrast, administration of alpha-2 adrenoceptor antagonists (idazoxan or yohimbine) increased the responses of the cell to brush, press and pinch stimuli. The background activity was also increased by idazoxan. The PAG-induced inhibition of the response to mechanical stimuli was reduced by idazoxan and yohimbine. These results suggest an involvement of alpha-2 adrenoceptors in the mechanism of PAG-induced inhibition of dorsal horn cell activity.

[Immunotherapy of primary habitual abortion]

OBJECTIVE

To investigate whether different number of times of immunization and different immunogens have any effect on the outcome of pregnancy in patients with history of primary habitual abortion.

METHODS

38 cases of pregnant women with history of primary habitual abortion immunized with lymphocytes were analysed retrospectively.

RESULTS

The results showed that the successful pregnancy rate was 87.5% (14/16) in the women immunized two times and was 86.4% (19/22) in the women immunized four times. There was no significant difference between the two groups. The successful pregnancy rate was 84.2% (16/19) in women immunized with their husbands' lymphocytes and 89.5% (17/19) in women immunized with donors' lymphocytes. There was also no significant difference between the two groups.

CONCLUSIONS

In order to prevent hematogenous infection, active immunization could be reduced from four to two times and the immunogens may be selected from the husband or from healthy donor.

[Experimental study on uptake of fluoride by dentin after pulsed Nd:YAG laser irradiation]

The purpose of this study was to determine the uptake of fluoride by dentin after pulsed Nd:YAG laser irradiation. Under SEM examination dentin lased by pulsed Nd:YAG laser appeared to be melted; there were no changes of calcium and phosphorus levels. Dentin irradiated by pulsed Nd:YAG laser and treated with 38% Ag(NH3)2F showed greater uptake and deep penetration of fluoride than topical application of fluoride alone, SEM examination revealed that CaF2-like and Ag3PO4-like deposits were formed on the dentin surface. These results suggested that pulsed Nd:YAG laser irradition could improve the absorption of fluoride in dentin.

Possible role of protein kinase C in the sensitization of primate spinothalamic tract neurons

The responsiveness of spinal cord nociceptive neurons to innocuous mechanical stimuli can be increased by the release of excitatory amino acids (EAAs) and peptides attributable to an injury-induced barrage of impulses. This sensitization of spinal dorsal horn neurons can also result from administration of phorbol ester by microdialysis, presumably by direct activation of protein kinase C (PKC). This study was designed to examine the effects of central sensitization of spinothalamic tract (STT) neurons produced by intradermal injection of capsaicin on the descending inhibition driven from the periaqueductal gray (PAG) and the possible role of PKC in this process in anesthetized monkeys. Sensitization of responses of STT cells to mechanical stimuli was induced by intradermal injection of capsaicin. PAG inhibition was significantly attenuated when sensitization of responses to mechanical stimuli occurred. However, perfusion of the spinal cord with NPC15437 (a selective PKC inhibitor) by microdialysis could prevent the sensitization of the responses to mechanical stimuli and the reduction in PAG inhibition of these responses induced by capsaicin injection. Results similar to those produced by capsaicin injection were observed when a PKC activator, phorbol ester (12-O-tetradecanoylphorbol-13-acetate), was infused within the dorsal horn by microdialysis. An inactive phorbol ester (4 alpha-phorbol 12,13-didecanoate) had no effect. These results provide evidence that the activation of PKC contributes to the development of central sensitization in dorsal horn neurons produced by chemical stimulation with capsaicin. Attenuation of the effectiveness of PAG inhibition takes place when the sensitization of dorsal horn cells develops, and PKC may play a significant role in this process.

The mouse BP-1 gene: structure, chromosomal localization, and regulation of expression by type I interferons and interleukin-7

The BP-1/6C3 antigen is a homodimeric, phosphorylated type II membrane integral glycoprotein expressed on immature B-lineage cells, bone marrow stromal cells, thymic cortical epithelial cells, endothelial cells, enterocytes, and renal proximal tubular cells. Biochemical and molecular analysis identified BP-1 as glutamyl aminopeptidase, an ectoenzyme that catalyzes the hydrolysis of acidic amino acid residues from the amino termini of regulatory peptides. We have isolated genomic clones that encode the BP-1 gene (gene symbol Enpep). The gene spans more than 110 kb and contains 20 exons. Except for the first and the last exons, it is composed of small exons ranging from 56 to 171 bp that are separated by introns ranging from less than 100 bp to approximately 10 kb. The zinc binding motif HEXXH and the glutamic acid residue 19 amino acids downstream, which also binds zinc, are encoded in exons 5 and 6. Primer extension analysis revealed a common major transcriptional start site in a pre-B cell line, in a bone marrow stromal cell line, and in kidney cells. The promoter region contains a TATA-like element and potential DNA-binding motifs for lymphocyte-specific transcription factors including Ikaros, BSAP, PU.1, and octamer binding proteins, as well as DNA binding motifs for several ubiquitous transcription factors. An interferon responsive element also located in the promoter region appeared to be functional, since type I interferons (IFN-alpha/IFN-beta) upregulated BP-1 expression in pre-B cell lines. A 2.1-kb promoter fragment, when fused to a luciferase reporter gene, was able to drive luciferase expression in pre-B cells, which normally express BP-1, and the Ag8 cells, in which BP-1 expression is extinguished. The BP-1/ Enpep gene was localized to a distal region of mouse chromosome 3 in a region homologous to human chromosome 4q25. Interestingly, while interleukin-7 (IL-7) induced both cell growth and increased BP-1 expression, IFN-alpha/IFN-beta upregulated BP-1 expression but inhibited IL-7 induced proliferation. This finding indicates that the upregulated BP-1 expression can be disassociated from the cell growth signal.

Antinociception and inhibition from the periaqueductal gray are mediated in part by spinal 5-hydroxytryptamine(1A) receptors

Although 5-hydroxytryptamine (5-HT) is known to be involved in the mediation of antinociception from the periaqueductal gray (PAG), its mode of action remains obscure. This investigation uses selective 5-HT(1A) receptor agonist and antagonist drugs in both behavioral and electrophysiological studies on antinociceptive mechanisms of the PAG of rats. Intraspinal administration of 8-hydroxy-dipropylaminotetralin hydrobromide (8-OH-DPAT), a selective 5-HT(1A) agonist, by microdialysis produced a dose-dependent antinociception in the radiant-heat paw withdrawal test. Dorsal horn neuronal activity was recorded extracellularly to test responses to noxious cutaneous stimuli when 8-OH-DPAT was administered iontophoretically, and it was observed that the noxious-evoked responses were inhibited in a current-related manner in all cells examined. The inhibitory effects elicited by 8-OH-DPAT could be selectively blocked by perfusion of the spinal cord with S-(--)-propranolol, a selective 5-HT(1A) antagonist. The antinociception produced by microinjection of morphine into the PAG was significantly attenuated in a dose-related manner by S-(--)-propranolol administered into the spinal cord. Similarly, the inhibition of dorsal horn neuronal responses to cutaneous mechanical stimuli produced by electrical stimulation in the PAG was reduced by S-(--)-propranolol administered into the spinal cord in the majority of cells tested. These data suggest that the release of 5-HT in the dorsal horn by stimulation in the PAG may act directly on spinal 5-HT(1A) receptors, resulting in inhibition of dorsal horn neurons. This is presumably one of the antinociceptive mechanisms of the descending serotonergic inhibitory pathway.

Adsorption of mixtures of bile salt taurine conjugates to lecithin-cholesterol membranes: implications for bile salt toxicity and cytoprotection

Tauroursodeoxycholate (TUDC), a relatively hydrophilic bile salt, reduces disruption of cholesterol-rich membranes by more hydrophobic bile salts such as taurocholate (TC), taurochenodeoxycholate (TCDC), or taurodeoxycholate (TDC). We examined the interactions of these bile salts in adsorption to large unilamellar vesicles to determine whether TUDC may stabilize membranes by preventing adsorption of more toxic bile salts. Fractional adsorption was quantified by rapid ultrafiltration. Adsorption coefficient Ai was defined for each bile salt i as ([bound i]/[free i])/[lecithin]. Affinity of different bile salts for lecithin vesicles varied with their relative hydrophobicity, increasing in the order TUDC < TC << TCDC < or = TDC. Ai of each bile salt fell with its accumulation on membranes, reaching a minimum at bound bile salt/lecithin mole ratio (B:L) between 0.05 and 0.1, then increasing with formation of higher-affinity mixed micelles. Inclusion of cholesterol in vesicles reduced Ai of all bile salts. In heterologous binding studies at submicellar concentrations, Ai of each bile salt varied with total B:L but was independent of the specific bile salts present on the membrane. Addition of TUDC to TDC reduced binding of TDC to membranes only slightly and lowered the threshold TDC concentration associated with transition to mixed micelles. However, above this threshold, TUDC markedly altered the adsorption of TDC to lecithin-containing phases. We conclude that TUDC does not directly stabilize membranes; rather, reduced permeabilization and dissolution of cholesterol-rich membranes after addition of TUDC to TDC may result from effects on the formation and structure of simple and mixed micelles.

Cloning and initial characterization of 14 myb-related cDNAs from tomato (Lycopersicon esculentum cv. Ailsa Craig)

myb-related transcription factors contain highly conserved DNA-binding domains. Using a mixture of degenerate oligonucleotides derived from the highly conserved region as probe, 14 myb-related clones were isolated from a cDNA library constructed using tomato hypocoyl mRNA. The expression of these clones was studied by northern blot analysis using poly(A)+ RNA from 7 tissue types (hypocotyl, leaf, root, green and red fruit, immature and mature flower). This study has revealed a wide range of expression patterns which include multiple and single transcripts, some of which show marked tissue specificity. Two clones showing different expression patterns have been fully sequenced. The DNA-binding domains of these two tomato myb clones are compared with myb genes from other plant species and organisms. Of the three clones analysed so far by Southern hybridization, two are single-copy genes and one has multiple genomic copies.

Role of GABA receptor subtypes in inhibition of primate spinothalamic tract neurons: difference between spinal and periaqueductal gray inhibition

1. gamma-Aminobutyric acid (GABA) is thought to inhibit both pre- and postsynaptically the transfer of nociceptive signals from primary afferent fibers to spinal dorsal horn sensory cells, including spinothalamic tract (STT) neurons. The inhibition can be mediated by both GABAA and GABAB receptors. We now attempt to characterize the synaptic inhibition of STT cells by spinal GABAA and GABAB receptors in anesthetized monkeys and to analyze the roles of these two receptor subtypes in the inhibition of STT cellular activity produced by stimulation in the periaqueductal gray (PAG). 2. Iontophoretic release of GABA or muscimol (a selective GABAA receptor agonist) onto STT cells elicited a profound and dose-related inhibition of the responses of all cells tested to noxious cutaneous stimuli. Only four cells (16.7%) were found to be inhibited when baclofen (a selective GABAB receptor agonist) was applied iontophoretically. However, a strong and dose-dependent inhibition of the responses to cutaneous mechanical and thermal stimuli was obtained in all cells examined when baclofen was administered into the dorsal horn through a microdialysis fiber. The inhibitory effects were mainly on nociceptive inputs. 3. The inhibition of cellular activity by GABAA and GABAB agonists could be selectively antagonized by specific antagonists applied through a microdialysis fiber. 4. The excitatory responses evoked by pulsed release of glutamic acid (GLUT) were also inhibited in a dose-related manner by iontophoretic application of GABA and muscimol, but not by baclofen. A high dose of baclofen administered by microdialysis resulted in only a small decrease in GLUT-evoked excitatory responses. 5. Infusion of GABAA and GABAB antagonists into the dorsal horn by microdialysis caused an increase in both background activity and responses to cutaneous stimuli, suggesting that there is a tonic GABAergic inhibition of STT cells. 6. The inhibition of responses to mechanical and thermal stimulation of the cutaneous excitatory receptive field resulting from stimulation in PAG was significantly antagonized in most of the STT cells tested when the GABAA antagonist bicuculline was infused into the spinal dorsal horn through a microdialysis fiber. In contrast, the inhibition produced by PAG stimulation in most of the cells examined was not significantly antagonized by the GABAB antagonists phaclofen or 3-amino-propyl(diethoxymethyl)phophinic acid (CGP35348) administered into the spinal dorsal horn by microdialysis. 7. Our results support the contention that GABAergic mechanisms in the spinal dorsal horn normally exert a tonic modulation of nociceptive inputs through both GABAA and GABAB receptors. The evidence provided here indicates that GABAA receptors located on primate STT neurons contribute to a postsynaptic inhibitory effect on the transmission of peripheral nociceptive inputs. A possible presynaptic GABAA action was not investigated. Our finding of a GABAB-receptor-mediated inhibition is consistent with the view that both pre- and postsynaptic GABAB receptors are involved in inhibitory modulation of spinal nociceptive transmission. Finally, it is suggested from this study that primate spinal GABAA, but not GABAB receptors, are involved in mediating the descending inhibition induced by PAG stimulation.

A single strand conformation polymorphism study of CD40 ligand. Efficient mutation analysis and carrier detection for X-linked hyper IgM syndrome

Mutations in the gene for CD40 ligand are responsible for the X-linked form of hyper IgM syndrome. However, no clinical or laboratory findings that reliably distinguish X-linked disease from other forms of hyper IgM syndrome have been reported, nor are there tests available that can be used to confidently provide carrier detection. To identify efficiently mutations in the gene for CD40 ligand, eight pairs of PCR primers that could be used to screen genomic DNA by single strand conformation polymorphism (SSCP) were designed. 11 different mutations were found in DNA from all 13 patients whose activated T cells failed to bind a recombinant CD40 construct. The exact nature of four of these mutations, a deletion and three splice defects, could not be determined by cDNA sequencing. In addition, SSCP analysis permitted rapid carrier detection in two families in whom the source of the mutation was most likely a male with gonadal chimerism who passed the disorder on to some but not all of his daughters. These studies document the utility of SSCP analysis for both mutation detection and carrier detection in X-linked hyper IgM syndrome.

CD38 signal transduction in human B cell precursors. Rapid induction of tyrosine phosphorylation, activation of syk tyrosine kinase, and phosphorylation of phospholipase C-gamma and phosphatidylinositol 3-kinase

Ligation of CD38 inhibits proliferation and induces apoptosis of human immature B cells, but the molecular mechanisms underlying this function are unknown. We found that CD38 dimerization with the specific mAbs T16 and IB4 induces rapid and transient tyrosine phosphorylation of several intracellular proteins in the immature B cell lines RS4;11, REH, 380, Nalm6, and OP-1. This effect could be markedly reduced by incubating cells with the tyrosine kinase inhibitors genistein, staurosporine, and herbimycin A. CD38 dimerization induced tyrosine phosphorylation of the protein kinase syk and increased syk kinase activity. CD38 dimerization also induced tyrosine phosphorylation of phospholipase C-gamma and of the p85 subunit of phosphatidylinositol 3-kinase (PI 3-K). The latter was accompanied by a distinct increase in PI 3-kinase activity in the immunoprecipitates obtained with an anti-phosphotyrosine Ab. In contrast to the signaling triggered by surface Ig engagement in B lymphocytes, CD38 ligation did not appear to induce tyrosine phosphorylation of the src-like protein tyrosine kinases lyn, fyn, and btk, or of vav- and ras-GTPase-activating protein, nor did it induce detectable changes in cytosolic CA2+ concentrations. CD38 signaling also differed from cytokine-induced signaling in that it did not cause tyrosine phosphorylation of Jak1 and Jak2. Finally, CD38 ligation did not inhibit IL-3-induced tyrosine phosphorylation of Jak2. These results identify CD38 as a cell surface receptor with signal transduction properties activated by dimerization. Induction of signal transduction by CD38 ligation implies the existence of a yet unidentified natural ligand of CD38.

CD38 signal transduction in human B cell precursors. Rapid induction of tyrosine phosphorylation, activation of syk tyrosine kinase, and phosphorylation of phospholipase C-gamma and phosphatidylinositol 3-kinase

Ligation of CD38 inhibits proliferation and induces apoptosis of human immature B cells, but the molecular mechanisms underlying this function are unknown. We found that CD38 dimerization with the specific mAbs T16 and IB4 induces rapid and transient tyrosine phosphorylation of several intracellular proteins in the immature B cell lines RS4;11, REH, 380, Nalm6, and OP-1. This effect could be markedly reduced by incubating cells with the tyrosine kinase inhibitors genistein, staurosporine, and herbimycin A. CD38 dimerization induced tyrosine phosphorylation of the protein kinase syk and increased syk kinase activity. CD38 dimerization also induced tyrosine phosphorylation of phospholipase C-gamma and of the p85 subunit of phosphatidylinositol 3-kinase (PI 3-K). The latter was accompanied by a distinct increase in PI 3-kinase activity in the immunoprecipitates obtained with an anti-phosphotyrosine Ab. In contrast to the signaling triggered by surface Ig engagement in B lymphocytes, CD38 ligation did not appear to induce tyrosine phosphorylation of the src-like protein tyrosine kinases lyn, fyn, and btk, or of vav- and ras-GTPase-activating protein, nor did it induce detectable changes in cytosolic CA2+ concentrations. CD38 signaling also differed from cytokine-induced signaling in that it did not cause tyrosine phosphorylation of Jak1 and Jak2. Finally, CD38 ligation did not inhibit IL-3-induced tyrosine phosphorylation of Jak2. These results identify CD38 as a cell surface receptor with signal transduction properties activated by dimerization. Induction of signal transduction by CD38 ligation implies the existence of a yet unidentified natural ligand of CD38.

The role of 5-HT3 receptors in periaqueductal gray-induced inhibition of nociceptive dorsal horn neurons in rats

Electrical stimulation in the periaqueductal gray (PAG) can inhibit dorsal horn cell responses to both innocuous and noxious cutaneous stimuli. This inhibition is believed to be due to the release of serotonin (5-HT) into the dorsal horn of the spinal cord from descending axons of the nucleus raphe magnus and the adjacent reticular formation. It is still not clearly known which subtypes of 5-HT receptors are involved in the PAG-induced inhibition. Extracellular single-unit recordings of dorsal horn cell activity, in combination with drug administration through a microdialysis fiber, were used to test the role of 5-HT3 receptors in PAG-induced inhibition. The responses of the cells to mechanical stimulation of the skin (BRUSH, PRESS and PINCH) and to the same stimuli while stimulating PAG were recorded. When the 5-HT3 antagonist, ondansetron, was perfused through the microdialysis fiber, not only was the background activity of the cell increased, but also the responses to BRUSH, PRESS and PINCH stimuli. The PAG-induced inhibition of responses to the same stimuli was partially or completely blocked by ondansetron. Another 5-HT3 antagonist, zacopride, did not increase the background activity or responses to PRESS and PINCH, yet this agent, like ondansetron, blocked PAG inhibition. The 5-HT3 agonist, phenylbiguanide, inhibited the background activity and the responses to mechanical stimuli. These results suggest that 5-HT released in the dorsal horn by stimulation in the PAG excites inhibitory interneurons through 5-HT3 receptors, resulting in inhibition of dorsal horn neurons.

[Clinical evaluation of force-sensitive probe in the examination of tooth sensitivity]

Two methods were tested for measuring the sensitivity of dentin to mechanical (force-sensitive probe) and cold air stimuli. Of the 212 sensitive teeth in 71 patients, 94.8% were sensitive to probe, with a mean threshold of 22.79g; 89.6% were sensitive to cold air. These two methods were significantly correlated (P < 0.001). The occlusal sites were less sensitive than the buccal sites measured by probe and cold air. It suggests that force-sensitive probe is a simple, quantitative method of measuring tooth hypersensitivity.

Clinical application of monoclonal antibody-drug conjugate to immunotargeting chemotherapy of bladder cancer

Monoclonal antibody-drug conjugate was applied in a clinical trial for patients with bladder cancer. Monoclonal antibody HB7A from a mouse splenocyte immunized against human bladder cancer was used as a drug carrier. The anti-cancer drug adriamycin (ADR) was bound to HB7A through a dextran (DEX) bridge to form the conjugate HB7A-DEX-ADR. The in vitro cytotoxic effect of the conjugate on BIU-87 bladder cancer cells was similar to that of free ADR and the mixture of HB7A and ADR. Seven patients with bladder cancer were given HB7A-DEX-ADR intravenously. The immunoperoxidase studies of the resected specimens showed that HB7A was localized specifically in cancer, and histological studies revealed degenerative and necrotic changes of the tumor cells. Patients receiving the conjugate did not experience serious side effects. This study suggests that immunotargeting chemotherapy with HB7A-DEX-ADR is well tolerated by patients and its cytotoxicity on tumor is substantial.

Resident bone marrow macrophages produce type 1 interferons that can selectively inhibit interleukin-7-driven growth of B lineage cells

Type 1 interferons alpha and beta are found to be potent inhibitors of IL-7-induced growth of early B lineage cells, while having no effect on cell growth induced by IL-2, IL-3, IL-4, or autogenous factors. The combination of IL-7 and interferons alpha/beta induces bcl-2 down-regulation and cell death by apoptosis. These conclusions were derived initially from experiments employing exogenous cytokines, but functional type 1 interferons are also shown to be produced by resident bone marrow macrophages. As physiological modulators of IL-7-driven proliferation and cell survival, interferons alpha/beta may cooperate with other homeostatic factors to maintain the balanced production of normal B lineage cells.

Astrocytes retrovirally transduced with BDNF elicit behavioral improvement in a rat model of Parkinson's disease

Neurotrophic factors that improve the survival of specific neuronal types during development and after exposure to various neuronal insults hold potential for treatment of neurodegenerative diseases. In particular, brain-derived neurotrophic factor (BDNF) has been shown to exert trophic and protective effects on dopaminergic neurons, the cell type known to degenerate in Parkinson's disease. To determine whether increased levels of biologically produced BDNF affect the function or regeneration of damaged dopaminergic neurons, the effects of grafting astrocytes transduced with the human BDNF gene into the striatum of the partially lesioned hemiparkinsonian rat were examined. Replication deficient retroviruses carrying either human prepro-BDNF or human alkaline phosphatase (AP) cDNA were used to transduce primary type 1 astrocytes purified from neonatal rat cortex. In vitro, BDNF mRNA was expressed by BDNF transduced astrocytes (BDNF astrocytes), but not control AP transduced astrocytes (AP astrocytes), as determined by reverse transcription polymerase chain reaction (RT-PCR). The modified astrocytes were injected into the right striatum 15 days after partial lesioning of the right substantia nigra with 6-hydroxydopamine. Transplantation of BDNF astrocytes, but not AP astrocytes, significantly attenuated amphetamine-induced rotation by 45% 32 days after grafting. Apomorphine-induced rotation increased over time in both groups, but was not significantly different in the BDNF-treated group. The modified BDNF astrocytes survived well with non-invasive growth in the brain for up to 42 days. Although BDNF mRNA positive cells were not detected within the graft site using in situ hybridization, alkaline phosphatase immunoreactive (IR) cells were present in control graft sites suggesting that the retroviral construct continued to be expressed at 42 days. Analysis of the density of tyrosine hydroxylase (TH)-IR fibers showed no effect of BDNF on TH-IR fiber density in the striatum on the lesioned side. These findings suggest that ex vivo gene therapy with BDNF ameliorates parkinsonian symptoms through a mechanism(s) other than one involving an effect of BDNF on regeneration or sprouting from dopaminergic neurons.

[Clinical and experimental study on codonopsis pilosula oral liquor in treating coronary heart disease with blood stasis]

The effects of Codonopsis pilosula oral liquor (CPOL) on tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI) in the plasma of 25 patients of coronary heart disease with blood stasis were studied. It has been shown that those patients had a significant decrease in t-PA activity (P < 0.01) compared to healthy subjects. After 4 weeks of CPOL therapy, platelet aggregation significantly decreased (P < 0.05), there was no significant difference in t-PA and PAI. From the results shown above, it suggested that one of the effects of CPOL in influencing blood coagulation was its inhibition on platelet aggregation, but not through the elevating of fibrinolytic activity.

Role of acetylcholine, corticoids and opioids in the rostral ventrolateral medulla in stress-induced hypertensive rats

Hypertension was induced in Sprague-Dawley and Wistar rats by irregular foot shocks combined with a buzzing noise for 2 h twice a day for 1-2 weeks. The plasma catecholamine, corticosterone, angiotensin II, glucose and lipids were found to increase in parallel. The acetylcholine (ACh) and choline acetyltransferase in rostral ventrolateral medulla (rVLM) increased markedly). Microinjection of ACh or cholinergic agonists into rVLM induced a pressor effect, and microinjection of M receptor blockers had a depressor effect. Electrophysiological studies showed that the stress-induced hypertension was closely related to the activation of a cholinergic system in rVLM. Microinjection of corticoids into rVLM had led to a pressor response which could be blocked by Ru38486, spironolactone, cholinergic blockers or verapamil. Microinjection of morphine and mu- or delta-receptor agonists into rVLM caused bradycardia and a reduction of arterial pressure that could be blocked by naloxone.

[Cryosurgery of acute hemorrhagic necrotizing pancreatitis]

Acute hemorrhagic necrotizing pancreatitis (AHNP) was induced by introduct retrograde injection of the autologous bile in canine. The cryoprobe was under the influence of temperature ranging from -160C to -190C for fifteen to eighteen seconds, and the frozen areas were about 80% surface of pancreas. Cryotherapy of AHNP strongly inhibited the development of the inflammation in pancreatic parenchyma. Postcryotherapy 24hr for remarkably decreased the activities of pancreatic enzymes. The activities of phospholipase A, lipase and amylase in serum decreased by 502.1%, 355.8%, 502.5% respectively in 7 days. The level of blood glucose decreased. At the second week, the fibroblasts were growing around the residual pancreatic aciner cells and insular cells rich in intact zymogen granules. The mortality (6.89%) of the treatment group within 48 hours was significantly lower than that of the control group (100%).

Archaic structure of the gene encoding transcription factor USF

The upstream stimulatory factor (USF) is a helix-loop-helix transcription factor that interacts with specific sites on the DNA that are also recognized by the MYC oncoproteins. We isolated genomic clones to the murine 44-kDa form of USF (USF2 gene). This unique gene spans 13 kilobases of DNA and is composed of 10 exons. The gene seems to have maintained its archaic structure, since many of the exons encode discrete functional domains of the transcription factor originally identified by protein sequence comparisons. A particularly striking HpaII tiny fragment island, extending over nearly 2,000 base pairs, surrounds the USF2 translation initiation site. This region, which includes the USF2 promoter and the first four exons, is characterized by an overall GC content greater than 74%. Analysis by S1 mapping and transient transfection assays revealed that the USF2 transcripts originate from an initiator element located within a highly GC-rich region that is surrounded by two long polyadenylate stretches and functions as a bidirectional promoter. Different forms of USF2 messages result from the presence or absence of the fourth exon in the processed USF2 mRNA. Alternative splicing correlates with the lack of a consensus lariat branch point in the third intron. Transient cotransfection assays revealed that the presence or absence of the amino acid sequences encoded by exon 4 affects considerably the transcription activation properties of the USF2 protein.

Glycine and GABAA antagonists reduce the inhibition of primate spinothalamic tract neurons produced by stimulation in periaqueductal gray

Amino acids are demonstrated to be important neurotransmitters mediating the inhibitory transmission from nucleus raphe magnus to spinal nociceptive dorsal horn neurons. In this study, the role of glycine and GABA in the inhibitory processes evoked by stimulation in periaqueductal gray (PAG) of responses of primate spinothalamic tract (STT) neurons to cutaneous mechanical and thermal stimuli was investigated by examining the effects of strychnine and bicuculline, antagonists of glycine and GABAA receptors, respectively, introduced into the dorsal horn through a microdialysis fiber. The inhibitory effects of iontophoretic application of glycine and GABAA agonists on STT cell activity evoked by noxious mechanical stimulation of the skin were selectively blocked by their specific antagonist, strychnine or bicuculline, infused into the dorsal horn. Similarly, intra-spinal application of strychnine or bicuculline resulted in a significant reduction in the PAG stimulation-induced inhibition of responses of STT cells to cutaneous stimuli. This reduction was mainly on the PAG-induced inhibition of the responses to noxious mechanical stimuli. Our results suggest that glycinergic and GABAergic inhibitory interneurons in the spinal cord dorsal horn synapsing on STT cells are activated during stimulation in PAG and contribute to descending antinociceptive actions.

Isolation and characterization of cDNA clones for chloroplast translational initiation factor-3 from Euglena gracilis

A complete cDNA clone encoding Euglena gracilis chloroplast translational initiation factor 3 (IF-3chl) has been obtained. Analysis of the sequence indicates that the IF-3chl mRNA contains the spliced leader found at the 5' end of nuclear encoded mRNAs in E. gracilis. The open reading frame for IF-3chl encodes a 537-amino acid protein. IF-3chl appears to be divided into four domains. The first 140 amino acids correspond to a transit peptide required for the import of IF-3chl into the chloroplast. The mature form of IF-3chl encompasses domains 2-4 and is about twice the size of Escherichia coli IF-3. The second domain has no homology to other known proteins. It begins with a stretch of 35 residues, of which about 30% are proline. Downstream from this region is a stretch of about 25 amino acids with a repeating (GX)n motif followed by a very acidic region. The third domain comprises a region of about 175 residues and has between 31 and 37% homology to the IF-3s found in other organisms. The IF-3 homology domain is followed by an acidic region which has no detectable homology to other sequences. Analysis of E. gracilis genomic DNA suggests that there are about four copies of the IF-3chl gene, one of which is probably a pseudogene. The activity of IF-3chl is inducible by light. However, the IF-3chl mRNA is present in approximately equal amounts in both dark- and light-grown cells, suggesting that the light-dependent induction of IF-3chl activity is post-transcriptional.

Ubiquitous expression of the 43- and 44-kDa forms of transcription factor USF in mammalian cells

USF is a helix-loop-helix transcription factor that, like Myc, recognizes the DNA binding motif CACGTG. Two different forms of USF, characterized by apparent molecular weights of 43,000 and 44,000, were originally identified in HeLa cells by biochemical analysis. Clones for the 43-kDa USF were first characterized, but only partial clones for the human 44-kDa USF (USF2, or FIP) have been reported. Here we describe a complete cDNA for the 44-kDa USF from murine cells. Analysis of this clone has revealed that the various USF family members are quite divergent in their N-terminal amino acid sequences, while a high degree of conservation characterizes their dimerization and DNA-binding domains. Interestingly, the 3' noncoding region of the 44-kDa USF cDNAs displayed an unusual degree of conservation between human and mouse. In vitro transcription/translation experiments indicated a possible role for this region in translation regulation. Alternative splicing forms of the 44-kDa USF messages exist in both mouse and human. Examination of the tissue and cell-type distribution of USF by Northern blot and gel retardation assays revealed that while expression of both the 43- and 44-kDa USF species is ubiquitous, different ratios of USF homo- and heterodimers are found in different cells.

Synthetic images by subspace transforms. I. Principal components images and related filters

The principal component (PC) approach offers compressions of an image sequence into fewer images and noise suppressing filters. Multiple MR images of the same tomographic slice obtained with different acquisition parameters (i.e., with different TR, TE, and flip angles), time sequences of images in nuclear medicine, and cardiac ultrasound image sequences are examples of such input image sets. In this paper noise relationships of original and linearly transformed image sequences in general, and specifically of original, PC, and PC-filtered images are discussed. As the spinoff, it introduces locally weighted PC transforms and filters, nonlinear PC's, and a single-image based filter for suppression of noise. Examples illustrate increased perceptibility of anatomical/functional structures in PC images and PC-filtered images, including extraction of physiological functional information by PC loading curves. Generally, the more correlated the original images are, the more effective is the PC approach.

Phase unwrapping through fringe-line detection in synthetic aperture radar interferometry

Interferometric synthetic aperture radar presents a new technology for performing high-resolution topographic mapping. One of the factors critical to mapping accuracy is phase unwrapping. This paper presents a new algorithm that unwraps phase through fringe-line detection. The algorithm is effective in preventing error propagation, it preserves the image resolution, and, in the mean time, it produces negligible local errors. An edge-segment linking approach and a curve-fitting approach are investigated, and their performances are compared. Test results of the algorithm are shown with the actual interferometric SEASAT synthetic aperture radar images over large-relief terrain near Yellowstone National Park with a short baseline, and results are shown over relatively flat terrain in Death Valley of California with a long baseline.