Characterization and functional study of five novel monoclonal antibodies against human OX40L highlight reverse signalling: enhancement of IgG production of B cells and promotion of maturation of DCs

OX40 ligand (OX40L), a molecule originally identified as human gp34, is an important co-stimulatory molecule during immune response. In this study, we report on five functional mouse anti-human OX40L monoclonal antibodies named as 9H10, 4C12, 8D10, 4H4 and 1G1, characterized by means of flow cytometry, Western blot and competition assay. These monoclonal antibodies bound to distinct OX40L epitopes on activated B cells and dendritic cells (DCs) and two of them could suppress the proliferation of T lymphocytes co-stimulated by mature DCs. Furthermore, we demonstrated that our monoclonal antibodies, such as 9H10 and 4C12, could trigger OX40L reverse signal that enhanced IgG production of B cells and promoted maturation of DCs as evidenced by the upexpression of CD80, CD86, CD83 and CXCR4 and monoclonal antibody 9H10 could also promote anti-CD40 monoclonal-antibody-stimulated DCs in order to induce T cells to secrete more interleukin-2 and interferon-gamma, which suggested that OX40L signals could strengthen the effect of CD40 signals on promoting Th1 differentiation.

Characterization and application of two novel monoclonal antibodies against CD40L: epitope and functional studies on cell membrane CD40L and studies on the origin of soluble serum CD40L

CD40 ligand, a 33-kDa cell membrane molecule, a member of the tumor necrosis factor superfamily, is an important costimulatory molecule during immune response. Here, we report on two functional mouse anti-human CD40L monoclonal antibodies 1B1 and 4F1 characterized by flow cytometry, Western blotting, and competition assay. The antibodies bound to distinct CD40L epitopes and therefore resulted in different bioactivity. Both antibodies could induce CD4+ T-cell alloantigenic hyporesponsiveness ex vivo. The antibodies were matched to develop a two-site enzyme-linked immunosorbent assay (ELISA) for soluble CD40L (sCD40L). Using this ELISA assay, we found major differences between plasma and serum sCD40L levels. Because the count of platelet sharply decreased in aplastic anemia (AA) and idiopathic thrombocytopenic purpura (ITP), we further analyzed the sCD40L concentration in the plasma of AA and ITP patients. The results showed that the sCD40L in serum was much lower than that of healthy subjects. These data demonstrate that platelets seem to be a major contributor to sCD40L, though not the only source of sCD40L in serum.

Repeated massage-like stimulation induces long-term effects on nociception: contribution of oxytocinergic mechanisms

Massage-like stroking induces acute antinociceptive effects that can be reversed by an oxytocin antagonist, indicating activation of oxytocin on endogenous pain controlling systems. We now demonstrate an increase in hindpaw withdrawal latencies (HWLs), in response to thermal and mechanical stimuli, which was present after six treatments of massage-like stroking every other day and which continued to increase through the remaining seven treatments. Repeated massage-like stroking also resulted in increased oxytocin-like immunoreactivity (oxytocin-LI) levels in plasma and periaquaductal grey matter (PAG). Furthermore, increases in HWLs were also present after injections of oxytocin into the PAG (0.1, 0.5 and 1.0 nmol). Intra-PAG oxytocin injection of 1 nmol followed by 1 or 20 nmol of naloxone attenuated the increments in HWL. Also, there was a dose-dependent attenuation of the oxytocin-induced antinociceptive effects following intra-PAG injection of the mu-opioid antagonist beta-funaltrexamine (beta-FNA) and the kappa-opioid antagonist nor-binaltorphimine (nor-BNI) but not the delta-antagonist naltrindole. The long-term antinociceptive effects of massage-like stroking may be attributed, at least partly, to the oxytocinergic system and its interaction with the opioid system, especially the mu- and the kappa-receptors in the PAG.

Cell death of olfactory receptor neurons in a rat with nasosinusitis infected artificially with Staphylococcus

Nasosinusitis is a common cause of acquired hyposmia or anosmia. To study the apoptotic death of olfactory receptor neurons in nasosinusitis, we made an inflammation model in rat infected with Staphylococcus. The histochemical changes in olfactory epithelium were examined using antibodies against protein gene product 9.5 (PGP 9.5), single-strand DNA (ssDNA), Bcl-2 and Bax that might be involved in the apoptosis of olfactory receptor neurons. The thickness of olfactory epithelium and the number of ssDNA-labeled cells were evaluated in each post-treatment group and the results were analyzed by two-way analysis of variance (ANOVA) and post hoc tests. Hematoxylin-eosin staining showed that a severe inflammatory reaction had occurred on the infected side of the nasal cavity and sinus, but not on the non-infected side. However, apoptosis of olfactory receptor neurons occurred on both sides; the apoptosis on the non-infected side started later and behaved like a shadow curve similarly to the infected side. Repeated measures ANOVA showed significant differences of both the thickness of olfactory epithelium (P < 0.0001) and the number of ssDNA-labeled cells (P = 0.0339) in the epithelium between the infected side and non-infected side comparing treatment, time and their interactions. Bcl-2 and Bax were detected only on the infected side in the early stages. Thus, nasosinusitis induced the apoptosis of olfactory receptor neurons. However, the apoptosis occurred not only on the infected side, but also on the non-infected side with no significant inflammation. The Bcl-2/Bax family seems to play an important role in the apoptosis induced by infection, but not in the apoptosis on the non-infected side. The results suggest that mechanisms of apoptosis of olfactory receptor neurons on the infected side may differ from those on the non-infected side.

Steric hindrance as a basis for structure-based design of selective inhibitors of protein-tyrosine phosphatases

Utilizing structure-based design, we have previously demonstrated that it is possible to obtain selective inhibitors of protein-tyrosine phosphatase 1B (PTP1B). A basic nitrogen was introduced into a general PTP inhibitor to form a salt bridge to Asp48 in PTP1B and simultaneously cause repulsion in PTPs containing an asparagine in the equivalent position [Iversen, L. F., et al. (2000) J. Biol. Chem. 275, 10300-10307]. Further, we have recently demonstrated that Gly259 in PTP1B forms the bottom of a gateway that allows easy access to the active site for a broad range of substrates, while bulky residues in the same position in other PTPs cause steric hindrance and reduced substrate recognition capacity [Peters, G. H., et al. (2000) J. Biol. Chem. 275, 18201-18209]. The current study was undertaken to investigate the feasibility of structure-based design, utilizing these differences in accessibility to the active site among various PTPs. We show that a general, low-molecular weight PTP inhibitor can be developed into a highly selective inhibitor for PTP1B and TC-PTP by introducing a substituent, which is designed to address the region around residues 258 and 259. Detailed enzyme kinetic analysis with a set of wild-type and mutant PTPs, X-ray protein crystallography, and molecular modeling studies confirmed that selectivity for PTP1B and TC-PTP was achieved due to steric hindrance imposed by bulky position 259 residues in other PTPs.

Comparison between EPI and HASTE for ultra-fast MR imaging of the human brain

Our purpose was to evaluate and compare the performance of ultra-fast single-shot T2-weighted sequences: echo-planar imaging (EPI) versus half-Fourier single-shot turbo spin-echo (HASTE) and to assess the usefulness of their combined reading. Comparative experiments on a phantom as well as a prospective clinical study in 47 patients were done. Axial images acquired with the following methods were compared: (a) HASTE; (b) segmented HASTE (s-HASTE); (c) single-shot spin-echo EPI (SE-EPI); and (d) gradient-echo EPI (GREEPI). Quantitative and qualitative criteria as well as lesion detectability were analyzed against the "gold standard" fast spin-echo (FSE) sequence. For contrast and contrast-to-noise ratio (CNR) between gray and white matter, GRE-EPI was best. The visibility of small markedly hyperintense lesion was best with HASTE and s-HASTE in the clinical study. Small hyperintense lesions were detected equally well with all four sequences, although all performed significantly worse than FSE. The two HASTE variants were better than the EPIs for the extraaxial lesions. The combination of the GRE-EPI and s-HASTE was judged best, and sometimes superior to the FSE image. HASTE or EPI alone cannot substitute for FSE in the screening evaluation of the brain. However, together, EPI and HASTE could provide comparable diagnostic information to that of FSE because their combination compensates for their individual limitations.

Changes of serum selenium in pregnant women with gestational diabetes mellitus

Gestational diabetes is one of the most common diseases in pregnancy. In the present work, the possible relationship between serum selenium concentration and gestational diabetes was investigated. Blood samples of 234 pregnant women were collected, including 98 subjects with impaired glucose tolerance (IGT), 46 subjects with gestational diabetes mellitus (GDM), and 90 normal pregnant women (NPW). An additional 17 samples of normal women of fertile age (NW) were collected for comparison. The hydride generation atomic fluorescence spectrometry was used for selenium determination. The mean serum selenium levels obtained for each group were 0.0741 +/- 0.0167 mg/L for NPW, 0.0631 +/- 0.0132 mg/L for IGT, 0.0635 +/- 0.0120 mg/L for GDM, and 0.108 +/- 0.0170 mg/L for NW. Serum selenium levels were significantly lower in pregnant woman with IGT (p < 0.001) and GDM (p < 0.001) than in NPW. Furthermore, an inverse correlation between the serum selenium concentration and the gestational period was also observed. Selenium supplementation during gestation for pregnant women, especially with IGT and GDM, should be considered.

Transcriptional regulation of cell-specific expression of the human cystathionine beta -synthase gene by differential binding of Sp1/Sp3 to the -1b promoter

Cystathionine beta-synthase (CBS) catalyzes the condensation of serine and homocysteine to form cystathionine, an intermediate step in the synthesis of cysteine. We previously characterized the CBS -1b minimal promoter (-3792 to -3667) and found that Sp1/Sp3, nuclear factor Y, and USF-1 were involved in the regulation of basal promoter activity (Ge, Y., Konrad, M. A., Matherly, L. H., Taub, J. W. (2001) Biochem. J. 357, 97-105). In this study, the critical cis-elements and transcription factors in the CBS -1b upstream region (-4046 to -3792) were examined in HT1080 and HepG2 cells, which differ approximately 10-fold in levels of CBS transcripts transcribed from the CBS -1b promoter. In DNase I footprint and gel shift analyses and transient transfections of mutant CBS -1b promoter constructs into HT1080 and HepG2 cells, transcriptionally important roles for Sp1/Sp3 binding to three GC boxes and one GT box and for binding of myeloid zinc finger 1-like proteins to two myeloid zinc finger 1 elements were indicated. In gel shift assays, very low levels of Sp1/Sp3 DNA-protein complexes were detected in HT1080 cells compared with HepG2 cells despite comparable levels of nuclear factor Y and USF-1 binding and similar levels of Sp1 and Sp3 proteins on Western blots. Mixing of HT1080 and HepG2 nuclear extracts resulted in no difference in total Sp factor binding in gel shift assays, thus excluding a role for an unknown activator or inhibitor in the disparate Sp1/Sp3 binding between the lines. Increased Sp1/Sp3 binding in gel shift assays was observed upon treatment of HT1080 nuclear extracts with protein kinase A, and decreased Sp1/Sp3 binding resulted from treatment of HepG2 nuclear extracts with calf alkaline phosphatase, suggesting a role for changes in Sp1/Sp3 phosphorylation in transcription factor binding and transactivation of the CBS -1b promoter. Characterization of CBS promoter structure and function should clarify the molecular bases for variations in CBS gene expression in genetic diseases and the relationship between CBS and Down syndrome.

Multiprotocol MR image segmentation in multiple sclerosis: experience with over 1,000 studies

RATIONALE AND OBJECTIVES

Multiple sclerosis (MS) is an acquired disease of the central nervous system. Several clinical measures are commonly used to express the severity of the disease, including the Expanded Disability Status Scale and the ambulation index. These measures are subjective and may be difficult to reproduce. The aim of this research is to investigate the possibility of developing more objective measures derived from MR imaging.

MATERIALS AND METHODS

Various magnetic resonance (MR) imaging protocols are being investigated for the study of MS. Seeking to replace the Expanded Disability Status Scale and ambulation index with an objective means to assess the natural course of the disease and its response to therapy, the authors have developed multiprotocol MR image segmentation methods based on fuzzy connectedness to quantify both macrosopic features of the disease (lesions, gray matter, white matter, cerebrospinal fluid, and brain parenchyma) and the microscopic appearance of diseased white matter. Over 1,000 studies have been processed to date.

RESULTS

By far the strongest correlations with the clinical measures were demonstrated by the magnetization transfer ratio histogram parameters obtained for the various segmented tissue regions. These findings emphasize the importance of considering the microscopic and diffuse nature of the disease in the individual tissue regions. Brain parenchymal volume also demonstrated a strong correlation with clinical measures, which suggests that brain atrophy is an important disease indicator.

CONCLUSION

Fuzzy connectedness is a viable, highly reproducible segmentation method for studying MS.

Early postnatal ethanol exposure selectively decreases BDNF and truncated TrkB-T2 receptor mRNA expression in the rat cerebellum

Binge-like ethanol exposure on postnatal day (PN) 4 induces a concentration dependent loss of Purkinje cells in the rat cerebellum. The mechanism of this ethanol-induced Purkinje cell vulnerability is not presently understood. Nevertheless, the specific timing of this vulnerability leads us to consider the neurotrophin system crucial to the regulation of neuronal development. Differentiation, maturation, and survival of Purkinje cells are shown to involve an intimate interaction between brain-derived nerve growth factor (BDNF) and neurotrophin-3 (NT3) acting primarily through their specific tyrosine-kinase (Trk) receptors. We believe that the specific ethanol vulnerability, and the timing of this vulnerability result from alterations in the BDNF-NT3 interplay. We hypothesize that disruption of TrkB and/or TrkC mediated neurotrophin communication is, in part, responsible for the ethanol-induced loss of Purkinje cells during development. The current study was undertaken to define the impact of ethanol exposure at the onset of ethanol vulnerability on the relative concentrations of mRNA encoding the neurotrophic factor receptors TrkB and TrkC. The reverse transcriptase (RT) polymerase chain reaction (PCR) amplification technique was used to identify the relative expression levels of mRNA specific to these receptors as well as the truncated TrkB receptor isoforms. We identify a specific decrease in overall TrkB receptor mRNA expression that is primarily a function of the TrkB-T2 receptor isoform. Concurrent decreases in mRNA specific to BDNF were also identified. No significant alterations to the expression of TrkC mRNA were found indicating that ethanol-exposure appears to act selectively on the BDNF communication system.

Brain atrophy in relapsing-remitting multiple sclerosis: fractional volumetric analysis of gray matter and white matter

PURPOSE

To determine the fractional brain tissue volume changes in the gray matter and white matter of patients with relapsing-remitting multiple sclerosis (MS) and to correlate these measurements with clinical disability and total lesion load.

MATERIALS AND METHODS

Thirty patients with relapsing-remitting MS and 25 healthy control subjects underwent magnetic resonance imaging. Fractional brain tissue volumes (tissue volume relative to total intracranial volume) were obtained from the total segmented gray matter and white matter in each group and were analyzed.

RESULTS

The fractional volume of white matter versus that of gray matter was significantly lower (-6.4%) in patients with MS (P <.0001) than in control subjects. Neither gray matter nor white matter fractional volume measurements correlated with clinical disability in the patients with MS.

CONCLUSION

Loss of brain parenchymal volume in patients with relapsing-remitting MS is predominantly confined to white matter. Analysis of fractional brain tissue volumes provides additional information useful in characterizing MS and may have potential in evaluating treatment strategies.

Biosynthesis of the thiazole moiety of thiamin in Escherichia coli: identification of an acyldisulfide-linked protein--protein conjugate that is functionally analogous to the ubiquitin/E1 complex

A covalently linked protein--protein conjugate between ThiF and ThiS thiocarboxylate was found in a partially purified coexpressed ThiF/ThiS protein mixture by using Fourier transform mass spectrometry. The Cys-184 of ThiF and the C terminus of ThiS thiocarboxylate were identified to be involved in the formation of this complex by using both mutagenesis and chemical modification methods. A complementation study of Escherichia coli thiF(-) using thiF(C184S) suggests that this conjugate is an essential intermediate involved in the biosynthesis of the thiazole moiety of thiamin. This ThiF/ThiS conjugate is the first characterized example of a unique acyldisulfide intermediate in a biosynthetic system. This protein conjugate is also an example of an ubiquitin-E1 like protein-protein conjugate in prokaryotes and supports a strong evolutionary link between thiamin biosynthesis and the ubiquitin conjugating system.

A novel mechanism of matrix metalloproteinase-9 gene expression implies a role for keratinization

To investigate the pathophysiological role of matrix metalloproteinase (MMP)-9 in the skin, we analyzed MMP-9 expression from human keratinocytes in culture. MMP-9 and the terminal differentiation marker involucrin were co-localized in the same keratinocytes with a high concentration of Ca(2+), a potent stimulator of differentiation. We identified the novel KRE-M9 element, further downstream to the previously reported TPA responsive element in the MMP-9 promoter, and both of these two elements were shown to be important for MMP-9 transcription and Ca(2+) induction. The concomitant upregulation of MMP-9 and involucrin transcripts was probably due to the very similar gene regulatory elements, KRE-M9 and KRE-4, in their respective promoters. These results indicate a novel mechanism of transcriptional regulation for MMP-9 in the process of keratinization, implying the probable association of apoptosis and differentiation of keratinocytes in epidermal skin tissue.

[Detection of positive-strand of transfusion transmitted virus fragment in the liver of cryptogenic hepatitis]

OBJECTIVE

To evaluate whether transfusion transmitted virus (TTV) replicates in the liver and to analyze the relationship between TTV and cryptogenic hepatitis.

METHODS

A 3.2 kb TTV fragment was detected by nested polymerase chain reaction (PCR) in 31 serum samples of patients with cryptogenic hepatitis who came from a school where was in an outbreak area of cryptogenic hepatitis during 1996 and in 30 healthy individuals. A hybridization/nuclease protection assay was used to detect positive-strand TTV fragment from the liver specimens of the 7 patients.

RESULTS

TTV DNA was detected in serum samples from 30 of 31 (96.9%) patients and from 18 of 30 (60%) healthy individuals, respectively. There was significant difference in the prevalence of TTV infection between the two groups. Based on hybridization/ nuclease protection assays, we detected positive-strand TTV fragment in all of 7 liver specimens of the patients.

CONCLUSIONS

TTV is related possibly to cryptogenic hepatitis. TTV can replicate in the liver. Although TTV only causes mild liver damage, a few patients will suffer from chronic hepatitis.

[A two-years clinical observation of all-ceramic restorations using Vita In-Ceram glass-infiltrated ceramic]

OBJECTIVE

This paper observed the clinical effect of Vita In-Ceram glass-infiltrated ceramic restorations.

METHOD

A total of 194 restorations (124 maxillary and 70 mandibular prostheses) made with Vita In-Ceram glass-infiltrated ceramic were examined in 45 patients. There were 165 anterior tooth crowns, 21 posterior tooth crowns, and 8 FPDs. Surface, color, anatomic form, and marginal integrity of restorations were assessed at 3 months, 6 months, 1 year and 2 years after cementation with the California Dental Association (CDA) quality assessment evaluation system.

RESULTS

It showed that the marginal fitness, color stability and strength of crowns were considered to be satisfactory. Only 0.01% (two crowns) were not acceptable. Two FPDs were not acceptable at 6-month visit, however, the anterior FPDs were considered to be satisfactory.

CONCLUSION

It is possible to constructexcellent all-ceramic prostheses with the Vita In-Ceram glass-infiltrated ceramic system.

Necessity of carnitine supplementation in semistarved rats fed a high-fat diet

We investigated the effects of carnitine supplementation on lipid metabolism in semistarved rats. The semistarved rats were fed a high-fat diet and half the normal energy intake for 2 wk. Carnitine was supplied daily at a dose of 250 mg/kg of body weight. The results showed that the concentration of plasma free carnitine increased significantly in semistarved and carnitine-supplemented rats compared with normal and semistarved rats. The activities of muscle carnitine palmitoyltransferase I and preheparin plasma lipoprotein lipase also were significantly increased in semistarved and carnitine-supplemented rats. The plasma triacylglycerol secretion rate was restored to normal by carnitine supplementation in semistarved rats. Urinary excretion of ketone bodies was reduced significantly after carnitine supplementation. We concluded that supplementation of carnitine can significantly increase the concentration of plasma free carnitine and improve lipid metabolism in semistarved rats fed a high-fat diet.

Transcriptional regulation of the human cystathionine beta-synthase -1b basal promoter: synergistic transactivation by transcription factors NF-Y and Sp1/Sp3

Cystathionine beta-synthase (CBS) catalyses the condensation of serine and homocysteine to form cystathionine, an intermediate step in the synthesis of cysteine. Human CBS encodes five distinct 5' non-coding exons, the most frequent termed CBS -1a and CBS -1b, each transcribed from its own unique GC-rich TATA-less promoter. The minimal transcriptional region (-3792 to -3667) of the CBS -1b promoter was defined by 5'- and 3'-deletions, and transient transfections of reporter gene constructs in HepG2 cells, characterized by CBS transcription exclusively from the -1b promoter. Included in this 125 bp region are 3 GC-boxes (termed GC-a, GC-b and GC-c), an inverted CAAT-box and an E-box. By gel-shift and supershift assays, binding of specificity protein (Sp)1 and Sp3 to the GC-box elements, upstream stimulatory factor 1 (USF-1) to the E-box, and both nuclear factor (NF)-Y and an NF-1-like factor to the CAAT box could be demonstrated. By transient trans fections and reporter gene assays in HepG2 and Drosophila SL2 cells, a functional interplay was indicated between NF-Y binding to the CAAT-box, or between USF-1 binding to the E-box, and Sp1/Sp3 binding to the GC-box elements. In SL2 cells, NF-Y and Sp1/Sp3 were synergistic. Furthermore, both Sp1 and the long Sp3 isoform transactivated the CBS -1b minimal promoter; however, the short Sp3 isoforms were potent repressors. These results may explain the cell- or tissue-specific regulation of CBS transcription, and clarify the bases for alterations in CBS gene expression in human disease and Down's syndrome.

Factors influencing the development of an anti-factor IX (FIX) immune response following administration of adeno-associated virus-FIX

The present study sought to determine the impact of the route of administration of an adeno-associated virus (AAV) vector encoding human factor IX (hFIX) on the induction of an immune response against the vector and its xenogenic transgene product, hFIX. Increasing doses of AAV-hFIX were administered by different routes to C57Bl/6 mice, which typically demonstrate significant immune tolerance to hFIX. The route of delivery had a profound impact on serum hFIX levels as well as the induction of an anti-hFIX humoral immune response. At all dose levels tested, delivery of AAV-hFIX by an intramuscular (IM) route induced an antibody response against the human FIX protein and no hFIX was detected in the serum of animals even at doses of 2 x 10(11) DNA viral particles (vp) of AAV-hFIX. This was in stark contrast to the mice that received AAV-hFIX by intraportal vein (IPV) administration. No anti-hFIX inhibitors were observed in any of these mice and therapeutic levels of hFIX were detected in the serum of all mice that received doses of 2 x 10(10) vp AAV-hFIX and higher. When pre-existing neutralizing immunity to AAV was established in mice, AAV-hFIX administration by either the IM or IPV routes did not result in detectable serum hFIX. Although hFIX expression was not observed in mice with pre-existing neutralizing immunity to AAV, an anti-hFIX response was induced in all of the animals that received AAV-hFIX by the IM route. This was not observed in the preimmune mice that received AAV-hFIX by IPV administration. These results suggest that the threshold of inducing an immune response against a secreted transgene product, in this case the xenoprotein hFIX, is lower when the vector is administered by the IM route even in animals with pre-existing immunity to AAV. (Blood. 2001;97:3733-3737)

Tissue-dependent alteration of protease expression phenotype in murine peritoneal mast cells that were genetically labeled with green fluorescent protein

The changing process of protease expression phenotype was studied after transplantation of peritoneal mast cells (PMCs). To pursue the fate of the transplanted PMCs, we obtained PMCs from WBB6F(1)-c-kit(+)/c-kit(+) mice with a transgene encoding green fluorescent protein (GFP). A large (n = 10(4)) or small (n = 500) number of PMCs was injected into the stomach wall of genetically mast cell-deficient WBB6F(1)-c-kit(W)/c-kit(Wv) mice without the GFP transgene. The original PMCs expressed messenger (m) RNAs of both mast cell carboxypeptidase A (MC-CPA) and mouse mast cell protease (mMCP)-2. The MC-CPA(+)/mMCP-2(+) phenotype did not change in both the muscularis propria and mucosa when 10(4) PMCs were injected. In contrast, when 500 PMCs were injected, the mast cells that developed in the muscularis propria showed MC-CPA(+)/mMCP-2(-) phenotype and those that appeared in the mucosa showed MC-CPA(-)/mMCP-2(+) phenotype. On day 1 after the injection of 500 PMCs, only approximately 20 GFP(+) cells were detected in the muscularis propria and no GFP(+) cells in the mucosa. The proportion of Alcian blue(+) cells decreased until day 7 and increased thereafter. The GFP(+) but Alcian blue(-) cells were considered as degranulated PMCS: The remarkable decrease or degranulation seemed to be necessary for the alteration of protease expression phenotype.

Phosphopantothenoylcysteine synthetase from Escherichia coli. Identification and characterization of the last unidentified coenzyme A biosynthetic enzyme in bacteria

Phosphopantothenoylcysteine synthase catalyzes the formation of (R)-4'-phospho-N-pantothenoylcysteine from 4'-phosphopantothenate and l-cysteine: this enzyme, involved in the biosynthesis of coenzyme A (CoA), has not previously been identified. Recently it was shown that the NH(2)-terminal domain of the Dfp protein from bacteria catalyzes the next step in CoA biosynthesis, the decarboxylation of (R)-4'-phospho-N-pantothenoylcysteine to form 4'-phosphopantetheine (Kupke, T., Uebele, M., Schmid, D., Jung, G., Blaesse, M., and Steinbacher, S. (2000) J. Biol. Chem. 275, 31838-31846). We have partially purified phosphopantothenoylcysteine decarboxylase from Escherichia coli and demonstrated that the protein encoded by the dfp gene, here renamed coaBC, also has phosphopantothenoylcysteine synthetase activity, using CTP rather than ATP as the activating nucleoside 5'-triphosphate. This discovery completes the identification of all the enzymes involved in the biosynthesis of coenzyme A in bacteria.

Enhancing patterns in multiple sclerosis: evolution and persistence

BACKGROUND AND PURPOSE

Contrast enhancement on MR images of patients with multiple sclerosis (MS) is known to be associated with abnormalities of the blood-brain barrier (BBB). However, little is known about diagnostic patterns and common features of enhanced MS lesions. This study was designed to evaluate initial enhancement patterns, changes in these enhancing patterns, and duration of enhancement in a cohort of patients with MS.

METHODS

Twenty-five patients with clinically definite MS were studied retrospectively. The appearance of enhancing lesions and sequential changes in the appearance on axial contrast-enhanced spin-echo images were evaluated. The enhancing lesions were classified as nodular, ringlike, or "other" (eg, arclike).

RESULTS

Of 301 new enhancing lesions, 205 (68%) showed nodular enhancement, 70 (23%) a ring pattern, and 26 (9%) a pattern neither nodular nor ringlike (eg, arclike). Two hundred eighty (93%) of 301 enhancing lesions disappeared within 6 months, and seven (2%) lesions showed persistent enhancement longer than 6 months. The other 14 (5%) lesions, which disappeared by the time of the next scan, were excluded, because the course between two examinations was longer than 6 months. Of nine persisting nodular enhancing lesions on the follow-up images, seven were decreased in size, whereas all of two persisting ringlike enhancing lesions on the follow-up images were larger than before.

CONCLUSION

Nodular enhancement is the predominant enhancement pattern for new MS lesions, and the temporal course of enhancement is usually shorter than 6 months. The appreciation of the evolution of MS-enhanced lesions aids in both identifying new MS lesions and distinguishing these lesions from other pathologic entities. This may be helpful in clinically evaluating the stage of MS lesions.

[The structures and characteristic infrared spectra of beta-DDB and its derivatives]

The characteristic infrared bands of the 3, 4-methylenedioxy-5-methoxybenzoate, 6-Br-3, 4-methylenedioxy-5-methoxybenzoate, beta-DDB (6, 6'-dimethoxy-4, 5, 4', 5'-dimethylenedioxy-2, 2'-dimethoxycarbonylbiphenyl) and its five derivatives were assigned. The effects of the substituents of these compounds on their IR data were discussed. The results indicated the varying of ester alkyl mainly influences the C=O double band stretching mode, but has little effects on the C=C double band stretching mode of the phenyl. When the H atom was substituted by other substituents, the absorptions of the C=O and C=C both changed.

Adenoviral gene transfer of Caenorhabditis elegans n--3 fatty acid desaturase optimizes fatty acid composition in mammalian cells

Omega--3 polyunsaturated fatty acids (PUFAs) are essential components required for normal cellular function and have been shown to exert many preventive and therapeutic actions. The amount of n--3 PUFAs is insufficient in most Western people, whereas the level of n--6 PUFAs is relatively too high, with an n--6/n--3 ratio of >18. These two classes of PUFAs are metabolically and functionally distinct and often have important opposing physiological functions; their balance is important for homeostasis and normal development. Elevating tissue concentrations of n--3 PUFAs in mammals relies on chronic dietary intake of fat rich in n--3 PUFAs, because mammalian cells lack enzymatic activities necessary either to synthesize the precursor of n--3 PUFAs or to convert n--6 to n--3 PUFAs. Here we report that adenovirus-mediated introduction of the Caenorhabditis elegans fat-1 gene encoding an n--3 fatty acid desaturase into mammalian cells can quickly and effectively elevate the cellular n--3 PUFA contents and dramatically balance the ratio of n--6/n--3 PUFAs. Heterologous expression of the fat-1 gene in rat cardiac myocytes rendered cells capable of converting various n--6 PUFAs to the corresponding n--3 PUFAs, and changed the n--6/n--3 ratio from about 15:1 to 1:1. In addition, an eicosanoid derived from n--6 PUFA (i.e., arachidonic acid) was reduced significantly in the transgenic cells. This study demonstrates an effective approach to modifying fatty acid composition of mammalian cells and also provides a basis for potential applications of this gene transfer in experimental and clinical settings.

Magnetization transfer ratio histogram analysis of gray matter in relapsing-remitting multiple sclerosis

BACKGROUND AND PURPOSE

Gray matter may be affected by multiple sclerosis (MS), a white matter disease. Magnetization transfer ratio (MTR) is a sensitive and quantitative marker for structural abnormalities, and has been used frequently in the imaging of MS. In this study, we evaluated the amount of MTR of gray matter among patients with relapsing-remitting MS and healthy control subjects as well as the correlation between gray matter MTR abnormality and neurologic disability associated with relapsing-remitting MS.

METHODS

We obtained fast spin-echo dual-echo and magnetization transfer (with and without MT saturation pulses) images from eighteen patients with relapsing-remitting MS and 18 age-matched healthy control subjects. Gray matter was segmented using a semiautomated system. Gray matter MTR histogram parameters, Kurtzke Expanded Disability Status Scale (EDSS), total T2 lesion volume, and gray matter volumes were obtained for statistical analysis.

RESULTS

A significant difference was found in gray matter MTR between patients with relapsing-remitting MS and healthy subjects (mean and median). Gray matter MTR histogram normalized peak heights in patients inversely correlated with EDSS (r = -0.65, P =.01). There was also an inverse correlation between mean MTR of gray matter and total T2 lesion volume.

CONCLUSION

The MTR of gray matter significantly differed between patients with relapsing-remitting MS and healthy control subjects, suggesting that MS is a more diffuse disease affecting the whole brain, and neuronal damage accumulates in step with T2 lesion volume. Our finding of the relationship between gray matter MTR and EDSS indicates that measurement of gray matter abnormality may be a potentially useful tool for assessing clinical disability in MS.

Electron capture dissociation of gaseous multiply charged ions by Fourier-transform ion cyclotron resonance

Fourier-transform ion cyclotron resonance instrumentation is uniquely applicable to an unusual new ion chemistry, electron capture dissociation (ECD). This causes nonergodic dissociation of far larger molecules (42 kDa) than previously observed (<1 kDa), with the resulting unimolecular ion chemistry also unique because it involves radical site reactions for similarly larger ions. ECD is highly complementary to the well known energetic methods for multiply charged ion dissociation, providing much more extensive protein sequence information, including the direct identification of N- versus C-terminal fragment ions. Because ECD only excites the molecule near the cleavage site, accompanying rearrangements are minimized. Counterintuitively, cleavage of backbone covalent bonds of protein ions is favored over that of noncovalent bonds; larger (>10 kDa) ions give far more extensive ECD if they are first thermally activated. This high specificity for covalent bond cleavage also makes ECD promising for studying the secondary and tertiary structure of gaseous protein ions caused by noncovalent bonding.

[Basic assessment of trust level in medical apparatus and instruments sales systems by medical organization]

Purchase of medical apparatus and instruments is a strict work of taking the patient as a consuming objection. To analyze the trust level in medical apparatus and instruments sales systems and to set up the method of trust level assessment before the purchase, is an important link of ensuring the reality of medical products and consumerism. According to the principle mentioned about, the present article analyses the basic content of assessing factors and their inter-relationship, summarizes their expressions, studies and sets up the mathematical modal and it method. All these are of some value to medical organization in choosing factory owners and their products while the purchasing.

EXAFS study on the local atomic structures around iron in glycosylated haemoglobin

Samples with 5.1%, 9.8% and 15.3% HbA1c were extracted from normal subjects and patients with slight and serious diabetes respectively. Extended x-ray absorption fine structure spectra of Fe K absorption were collected at the EXAFS experimental station of the Beijing Synchrotron Radiation Facility. The step-by-step fluorescent mode was employed with a count time of 10 s per point. Several independent scans were averaged to eliminate the statistical noise. Reference backscattering amplitudes and phaseshifts were calculated using the curve wave theory (FEFF code) of EXAFS. Apart from the nitrogen neighbours around the central iron atom, oxygen neighbours are also found. The Fe-N bond length increases by about 0.02 A for the sample with 15.3% HbA1c compared with the others, but the Fe-O bond length is almost unchanged. With increasing of HbA1c concentration, the content of Hb increases and the content of HbO2 decreases. This demonstrates that the glycosylation of haemoglobin will decrease its ability to carry oxygen.

Introduction of human erythropoietin receptor complementary DNA by retrovirus-mediated gene transfer into murine embryonic stem cells enhances erythropoiesis in developing embryoid bodies

To evaluate the role of the erythropoietin (Epo) receptor (R) in erythropoiesis in more primitive stem cells, we assessed the influence of retrovirus-mediated gene transfer of human (h) EpoR complementary DNA (cDNA) into murine embryonic stem (ES) cells on erythroid differentiation of these cells. The hEpoR cDNA was efficiently transduced into ES cells, forming hEpoR that stably expressed ES (ES-hEpoR) cells. Expression of hEpoR cDNA was confirmed in ES-hEpoR cells by reverse transcriptase-polymerase chain reaction and Northern blot analysis. Colony assays demonstrated that definitive erythroid and primitive erythroid colonies were significantly increased from ES-hEpoR cells, when compared with mock virus-transduced ES (ES-Neo) cells, during the time course of differentiation induced by withdrawal of leukemia inhibitory factor, in either the presence or the absence of Epo. Multipotential colony-forming units (CFU-Mix) were also increased in ES-hEpoR cells at different stages of differentiation, but no changes were detected for CFU-granulocyte-macrophage colonies (CFU-GM). Time course studies by Northern blot analysis demonstrated elevated levels of expression of beta-H1 and beta-Major globin genes in embryoid bodies derived from ES-hEpoR cells stimulated with Epo, when compared with similar expression from ES-Neo cells. Expression of the GATA-1 gene was enhanced in ES-hEpoR cells, when compared with ES-Neo cells, beginning immediately after initiation of the cultures until 8 days of differentiation. These data indicate that primitive and definitive erythropoiesis in differentiating embryoid bodies can be enhanced by retrovirus-mediated gene transfer of an hEpoR gene.

Independent influence of strain difference and mi transcription factor on the expression of mouse mast cell chymases

Expression of mouse mast cell protease (mMCP) genes was examined with particular attention to the transactivation effect of mi transcription factor (MITF) and the expression differences between C57BL/6 (B6) and WB strains. We had reported the enhancing effect of MITF on the expression of mMCP-4, -5, and -6 genes in cultured mast cells (CMCs) of B6 strain, and in the present study we demonstrated the enhancing effect on the expression of mMCP-2 and -9 genes as well. The enhancing effect of MITF on the expression of mMCP-2, -4, -5, -6, and -9 genes was also detected in CMCs of the WB strain. The regulation of mMCP-2, -4, and -9 genes was localized to a specific promoter element (CANNTG) which was recognized and bound by MITF and which was conserved between the B6 and WB strains. On the other hand, the expression of mMCP-2, -4, and -9 genes was smaller in CMCs of the B6 strain when compared to their expression in CMCs of the WB strain. Although mMCP-5 is a chymase as mMCP-2, -4, and -9, and genes encoding all of the chymases are located on chromosome 14, the mMCP-5 gene was regulated in a manner distinct from mMCP-2, -4, and -9 genes.

Electrochemically controlled hydrogen bonding. o-Quinones as simple redox-dependent receptors for arylureas

9,10-Phenanthrenequinone and acenaphthenequinone are shown to act as simple redox-dependent receptors toward aromatic ureas in CH(2)Cl(2) and DMF. Reduction of the o-quinones to their radical anions greatly increases the strength of hydrogen bonding between the quinone carbonyl oxygens and the urea N-hydrogens. This is detected by large positive shifts in the redox potential of the quinones with no change in electrochemical reversibility upon addition of urea guests. Cyclic voltammetric studies with a variety of possible guests show that the effect is quite selective. Only guests with two strong hydrogen donors, such as O-H bonds or amide N-H bonds, that are capable of simultaneously interacting with both carbonyl oxygens give large shifts in the redox potential of the quinones. The electronic character and conformational preference of the guest are also shown to significantly affect the magnitude of the observed potential shift. In the presence of strong proton donors the electrochemistry of the quinone becomes irreversible indicating that proton transfer has taken place. Experiments with compounds of different acidity show that the pK(a) of the protonated quinone radical is about 15 on the DMSO scale, >4 pK(a) units smaller than that of 1,3-diphenylurea. This is further proof that hydrogen bonding and not proton transfer is responsible for the large potential shifts observed with this and similar guests.

Some nutritional and functional properties of defatted wheat germ protein

Defatted wheat germ protein (DWGP) was isolated by alkaline extraction at pH 9.5 and subsequent isoelectric precipitation at pH 4.0, and its nutritional and functional properties were studied. The results showed that the amino acid content of defatted wheat germ was as high as 26.793 g/100 g, and the contents of eight essential amino acids were all relatively high. The isoelectric point of DWGP was 4.0. When pH >6.0, the DWGP had high solubility with a nitrogen solubility index of 70%. The emulsifying activity and emulsifying stability of DWGP were similar to those of bovine serum albumin and a little higher than those of casein. DWGP had good foaming capacity, but its foaming stability (FS) was not very good. However, the FS of DWGP can be improved through physical, chemical, or enzymatic methods. Moreover, DWGP had excellent water retention (WR); especially at pH 8.0 and a temperature of 70 degrees C, the WR of DWGP was the highest at 229.4%. DWGP offers is a potential source of functional protein isolate for possible food applications.

Co-transduction of cDNAs for c-kit and steel factor into single CD34+ cord blood cells further enhances the growth of erythroid and multipotential progenitors

Previous studies have demonstrated that the c-kit encoded tyrosine kinase receptor and its ligand, steel factor (SLF), are critical for normal blood cell development. We have reported that transduction of the c-kit gene into single hematopoietic progenitor cells (HPC), CD34(+++) cells, from cord blood (CB) enhances erythroid colony formation via a SLF-dependent mechanism. We therefore decided to evaluate the impact on cell proliferation of co-transducing c-kit and SLF cDNAs into these cells. CD34(+++) cells were sorted as a population or as 1 cell/well for cells expressing the highest levels of CD34 and different levels of c-kit. Cells were then prestimulated with granulocyte macrophage (GM)-colony stimulating factor (CSF), interleukin (IL)-3, IL-6, erythropoietin (Epo) in the presence and absence of various concentrations of SLF. Cells were then transduced with SLF and/or c-kit cDNAs, and then assayed for colony formation with the same cytokine combination. At a single cell level, co-transduction with c-kit and SLF genes significantly enhanced colony formation compared with individual gene transduction, especially by erythroid and multipotential progenitors that responded to stimulation by added cytokines. Little or no growth was seen with the c-kit- and/or SLF-transduced cells without addition of cytokines. The degree of enhancement effected by co-transduction inversely correlated with the degree of expression of c-kit protein before transduction. Optimal enhancing effects were noted in CD34(+++) kit(Lo/-) cells co-transduced with both c-kit and SLF cDNAs. Reverse transcriptase-polymerase chain (RT-PCR) analysis of SLF mRNA expression in CD34(+++) cells and enzyme-linked immunoadsorbent assay (ELISA) measurement of secreted SLF protein demonstrated that the transduced SLF cDNA was expressed and soluble SLF was released in medium cultured with SLF gene transduced MACS-separated CD34(+) cells in the presence, but not in the absence, of IL-3, GM-CSF, IL-6, and Epo. These results demonstrate the enhancement of the proliferation of growth factor responsive HPC that express transduced c-kit and SLF genes.

Cystathionine-beta-synthase cDNA transfection alters the sensitivity and metabolism of 1-beta-D-arabinofuranosylcytosine in CCRF-CEM leukemia cells in vitro and in vivo: a model of leukemia in Down syndrome

The significantly higher event-free survival rates of Down syndrome (DS) children with acute myeloid leukemia compared with non-DS children is linked to increased sensitivity of DS myeloblasts to 1-beta-D-arabinofuranosylcytosine (ara-C) and the enhanced metabolism of ara-C to ara-C triphosphate (J. W. Taub et al., Blood, 87: 3395-3403, 1996). The cystathionine-beta-synthase (CBS) gene (localized to chromosome 21q22.3) may have downstream effects on reduced folate and S-adenosylmethionine pathways; ara-C metabolism and folate pools are linked by the known synergistic effect of sequential methotrexate and ara-C therapy. We have shown that relative CBS transcripts were significantly higher in DS compared with non-DS myeloblasts, and CBS transcript levels correlated with in vitro ara-C sensitivity (J. W. Taub et al., Blood, 94: 1393-1400, 1999). A leukemia cell line model to study the relationship of the CBS gene and ara-C metabolism/sensitivity was developed by transfecting CBS-null CCRF-CEM cells with the CBS cDNA. CBS-transfected cells were a median 15-fold more sensitive in vitro to ara-C compared with wild-type cells and generated 8.5-fold higher [3H]ara-C triphosphate levels after in vitro incubation with [3H]ara-C. Severe combined immunodeficient mice implanted with CBS-transfected CEM cells demonstrated greater responsiveness to therapy, reflected in significantly prolonged survivals after ara-C administration compared with mice implanted with wild-type cells and treated with the same dosage schedule. The transfected cells also demonstrated increased in vitro and in vivo sensitivity to gemcitabine. Deoxycytidine kinase (dCK) activity was approximately 22-fold higher in transfected CEM cells compared with wild-type cells. However, levels of dCK transcripts on Northern blots and protein levels on Western blots were nearly identical between CBS-transfected and wild-type cells. Collectively, these results suggest a posttranscriptional regulation of dCK in CBS-overexpressing cells that contributes to increased ara-C phosphorylation and drug activity. Further elucidating the mechanisms of increased sensitivity of DS cells to ara-C related to the CBS gene may lead to the application of these novel approaches to acute myeloid leukemia therapy for non-DS patients.

Numerical tissue characterization in MS via standardization of the MR image intensity scale

Image intensity standardization is a recently developed postprocessing method that is capable of correcting the signal intensity variations in MR images. We evaluated signal intensity of healthy and diseased tissues in 10 multiple sclerosis (MS) patients based on standardized dual fast spin-echo MR images using a numerical postprocessing technique. The main idea of this technique is to deform the volume image histogram of each study to match a standard histogram and to utilize the resulting transformation to map the image intensities into standard scale. Upon standardization, the coefficients of variation of signal intensities for each segmented tissue (gray matter, white matter, lesion plaques, and diffuse abnormal white matter) in all patients were significantly smaller (2.3-9.2 times) than in the original images, and the same tissues from different patients looked alike, with similar intensity characteristics. Numerical tissue characterizability of different tissues in MS achieved by standardization offers a fixed tissue-specific meaning for the numerical values and can significantly facilitate image segmentation and analysis.

Anti-Tumor CC49-zeta CD4 T cells possess both cytolytic and helper functions

The authors report that the nature of the T-cell-receptor--derived signal in normal CD4+ T cells can induce interleukin-2 (IL-2) secretion or perforin-mediated cytolytic activity. Normal human T cells were genetically modified to express the tumor antigen specific chimeric immune receptor, CC49-zeta. The CC49-zeta chimeric immune receptor is comprised of the intracellular signaling domains of the TCR CD3zeta protein fused to the single chain scFv of the humanized CC49 antibody, which binds the pan-adenocarcinoma tumor antigen TAG-72. Patient-specific T cells genetically modified to express the CC49-zeta receptor have been used in patients with colon cancer. The authors report that both CD4 and CD8 T cells expressing the CC49-zeta receptor mediated the major histocompatibility complex-unrestricted lysis of TAG-72--expressing tumor cells with comparable efficiency. However, although the CC49-zeta receptor mediated target cell lysis, it did not support the production of IL-2, even in the presence of CD28 stimulation. Robust IL-2 secretion and T-cell proliferation were observed when the same CD4 CC49-zeta T cells were stimulated through the CD28 receptor and endogenous T-cell receptor. These results indicate that CD4 T lymphocytes possess the capacity to act as both cytolytic and helper T cells and that this difference in effector function is controlled by the nature of the T-Cell receptor--derived signals.

Activated ion electron capture dissociation for mass spectral sequencing of larger (42 kDa) proteins

In previous studies, electron capture dissociation (ECD) has been successful only with ionized smaller proteins, cleaving between 33 of the 153 amino acid pairs of a 17 kDa protein. This has been increased to 99 cleavages by colliding the ions with a background gas while subjecting them to electron capture. Presumably this ion activation breaks intramolecular noncovalent bonds of the ion's secondary and tertiary structure that otherwise prevent separation of the products from the nonergodic ECD cleavage of a backbone covalent bond. In comparison to collisionally activated dissociation, this "activated ion" (AI) ECD provides more extensive, and complementary, sequence information. AI ECD effected cleavage of 116, 60, and 47, respectively, backbone bonds in 29, 30, and 42 kDa proteins to provide extensive contiguous sequence information on both termini; AI conditions are being sought to denature the center portion of these large ions. This accurate "sequence tag" information could potentially identify individual proteins in mixtures at far lower sample levels than methods requiring prior proteolysis.

Study on polymorphism of MICA exon 5 microsatellite in Shanghai Han population

OBJECTIVE

To investigate the polymorphism distribution of MICA gene exon 5 microsatellite in Shanghai Han population and study the relationship of MICA gene and its closely linked gene HLA B.

METHODS

The microsatellite polymorphism of MICA exon 5 in 175 unrelated healthy individuals were investigated using PCR-heteroduplex analysis.

RESULTS

(1)There are 5 alleles of the microsatellite polymorphism in exon 5 of the MICA gene in Shanghai Han population, the gene frequency of MICA*A5 is the highest(39.14%), the next is MICA*A5.1(22.29%). (2)There is strong linkage disequilibrium between the HLA-B and MICA STR loci, e.g. MICA*A5 and HLA-B15, MICA*A4 and HLA-B27.

CONCLUSION

The polymorphism distribution of MICA gene and the linkage disequilibrium between MICA and HLA-B have deviations in different ethnic groups.

Enhancement of proliferation and differentiation of erythroid progenitors by co-transduction of erythropoietin receptor and H-ras cDNAS into single CD34(3+) cord blood cells

Our previous studies have demonstrated that retrovirus-mediated gene transduction of either the human erythropoietin receptor (EpoR) or H-ras cDNA into single purified hematopoietic progenitor (HPC), CD34(3+), cells from cord blood (CB) resulted in increased numbers and sizes of erythroid cell containing colonies. We therefore evaluated if there were further effects when H-ras and EpoR genes were co-transduced into the same progenitor cells. Highly purified single sorted CD34(3+) CB cells were transduced with retroviral vectors encoding EpoR or H-ras cDNA. At the single cell level, and in response to stimulation by a combination of growth factors, including Epo, the number of colonies formed by BFU-E and CFU-GEMM was significantly increased in cells transduced with either single H-ras or EpoR cDNA compared to mock virus-transduced cells as previously described. Increased numbers of BFU-E, but not CFU-GEMM, colonies were produced from cells simultaneously co-transduced with both EpoR and Hras genes. Little or no growth was seen in transduced cells without exogenously added cytokines. The size of all types of colonies including CFU-GM was increased in cells transduced with H-ras and/or EpoR cDNAs, and the greatest increase was noticed in cells co-transduced with both genes. Integration and expression of either gene in individual colonies as assessed by PCR and RT-PCR analysis were 45-62% and 48-58%, respectively, with approximately 31% of the cells containing and expressing both genes. These results add to information suggesting an enhancing interacting role of H-ras and EpoR in erythroid proliferation/differentiation.

An orthogonal moment-based method for automatic verification of radiation field shape

The purpose of this paper is to develop a new method for automated on-line verification of the treatment field shape during radiotherapy. The treatment field boundary is extracted from the digital portal image and is then approximated by a polygon. The proposed procedure used one of the approved field shapes as the reference boundary for automated comparison with subsequent portal field boundaries. The orthogonal moment-based method was applied to align treatment field boundaries that include the translational shifts, scaling factor and rotation angle. Firstly, the moments of order up to one were used to adjust the magnification and translation of the test field boundary related to the reference one; this step created a common coordinate system for the two images. Then a quadratic least-square objective function based on the orthogonal moments (e.g. Legendre moments) of the two field shapes was employed to perform rotational correction. Since moment computation by a straightforward method required a large number of multiplication and addition operations, a fast method for computing Legendre moments was also developed to decrease the calculation time. Application of the method to some simulated cases showed that our alignment procedure has an accuracy of 0.5 mm in detecting translational shift, 0.004 in detecting magnification and less than 0.3 degrees in detecting rotation angle between the test shape and the reference shape. The alignment procedure using the proposed method can be done within 2 s on a Pentium II personal computer. Therefore, our method is potentially useful for automated real-time treatment field shape verification.

Localization of endotoxin in the rat intestinal epithelium

High levels of circulating lipopolysaccharide (LPS) cause intestinal inflammation and increased permeability to bacteria and toxins. To better understand the effects of LPS on the gut, confocal microscopy and immunofluorescence staining were used to examine the distribution of LPS in the rat intestine after intravenous or enteral administration. LPS was localized in macrophages in the lamina propria from 1 h to >28 days after intravenous injection. LPS was also detected in the epithelial cells from 8 h to 7 days after injection. In contrast, LPS administered enterally was found in the gut lumen in close proximity to the mucosa but was not detected in enterocytes at any time. The concentration of LPS in enterocytes near the villus tip provides a mechanism for the clearance of endotoxin, by the turnover and shedding of LPS-containing enterocytes into the gut lumen, that has not been previously described.

Long-term differential modulation of genes encoding orexigenic and anorexigenic peptides by leptin delivered by rAAV vector in ob/ob mice. Relationship with body weight change

We investigated the long-term effects of physiological levels of leptin produced by gene therapy on body weight (BW) and expression of genes that encode orexigenic and anorexigenic peptides in the hypothalamus. Recombinant adeno-associated viral vector (rAAV), a non-pathogenic and non-immunogenic vector, encoding leptin (betaOb) was generated and administered iv to ob/ob mice lacking endogenous leptin. Whereas the lowest dose of rAAV-betaOb (6x10(9) particles) was ineffective, the middle dose (6x10(10) particles) curbed BW gain without affecting food consumption for 75 days of observation. A ten-fold higher dose (6x10(11) particles) resulted in increased blood leptin levels and suppressed both BW gain and food consumption throughout the duration of the experiment. rAAV-betaOb doses that either curbed BW without affecting food consumption or evoked BW loss and reduced food intake, decreased the expression of genes encoding the orexigenic peptides, neuropeptide Y and agouti-related peptide in the ARC, and the two doses were equally effective. Concomitantly, the expression of genes encoding the anorexigenic peptide, alpha-melanocyte stimulating hormone and cocaine-and-amphetamine regulatory transcript, was augmented with the latter gene displaying a dose-dependant response. These results document the efficacy of delivering biologically active leptin for extended periods by an iv injection of rAAV-betaOb and show that physiological leptin concentrations simultaneously exert a tonic inhibitory effect on orexigenic and a stimulatory effect on anorexigenic signaling in the hypothalamus. This intricate dynamic interplay induced by leptin regulates BW with or without an effect on food intake in leptin-deficient ob/ob mice. Further, these results suggest that gene therapy is an effective mode of delivery to the hypothalamus of those therapeutic proteins that cross the blood-brain barrier to ameliorate neuroendocrine disorders.