Oral aminolevulinic acid induces protoporphyrin IX fluorescence in psoriatic plaques and peripheral blood cells

Photodynamic therapy (PDT) with topical aminolevulinic acid (ALA) has been shown in previous studies to improve psoriasis. However, topical ALA-PDT may not be practical for the treatment of extensive disease. In order to overcome this limitation we have explored the potential use of oral ALA administration in psoriatic patients. Twelve patients with plaque psoriasis received a single oral ALA dose of 10, 20 or 30 mg/kg followed by measurement of protoporphyrin IX (PpIX) fluorescence in the skin and circulating blood cells. Skin PpIX levels were determined over time after ALA administration by the quantification of the 635 nm PpIX emission peak with in vivo fluorescence spectroscopy under 442 nm laser excitation. Administration of ALA at 20 and 30 mg/kg induced preferential accumulation of PpIX in psoriatic as opposed to adjacent normal skin. Peak fluorescence intensity in psoriatic and normal skin occurred between 3 and 5 h after the administration of 20 and 30 mg/kg, respectively. Ratios of up to 10 for PpIX fluorescence between psoriatic versus normal skin were obtained at the 30 mg/kg dose of ALA. Visible PpIX fluorescence was also observed on normal facial skin, and nonspecific skin photosensitivity occurred only in patients who received the 20 or 30 mg/kg doses. PpIX fluorescence intensity was measured in circulating blood cells by flow cytometry. PpIX fluorescence was higher in monocytes and neutrophils as compared to CD4+ and CD8+ T lymphocytes. PpIX levels in these cells were higher in patients who received higher ALA doses and peaked between 4 and 8 h after administration of ALA. There was only a modest increase in PpIX levels in circulating CD4+ and CD8+ T lymphocytes. In conclusion oral administration of ALA induced preferential accumulation of PpIX in psoriatic plaques as compared to adjacent normal skin suggesting that PDT with oral ALA should be further explored for the treatment of psoriasis.

[The apolipoprotein E gene polymorphism in children with steroid-resistant idiopathic nephrotic syndrome]

OBJECTIVE

To study apolipoprotein E gene polymorphism in children with steroid- resistant idiopathic nephrotic syndrome (SRINS).

METHODS

Sixty children with SRINS (including 9 children with focalsclerosing glomerulonephritis) were observed in comparison with 80 age-sex-matched healthy children. Seven lipoprote in metabolism parameters including serum total-cholesterol(TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apolipoprotein AI(apoAI), apolipoprotein B (apoB), lipoprotein (a)[Lp (a)] were detected by enzyme method, and single-strand conformation polymorphism(PCR-SSCP) was used to determine the apoE genotypes in the two groups.

RESULTS

Serum TC, TG, HDL-C, LDL-C, apoAI, apoB, Lp(a) in the observation group were significantly higher than those in the healthy controls (P<0.01). After 6 months, the levels of serum TC, TG, LDL-C,apoB,Lp(a) were 81.25%, 78.13%, 84.38%, 87.50% and 78.13% respectively in 32 SRINS cases of the observation group. The apo epsilon 2 allele gene frequence was higher in the observation group than in the controls (11.66% vs 5.00%, P<0.05). The apo apsilon 2 allele gene frequence in the cases of focalsclerosing glomerulonephritis was significantly higher than that in the controls (22.22% vs 5.00%, P<0.01).

CONCLUSION

The above results indicate the obvious and long term abnormalities of serum lipoprotein metabolism in the children with SRINS. The apo apsilon 2 allele gene frequence is higher in the children with SRINS. There are risk factors for atherosclerosis and cardiovascular diseases in the children with SRINS. The antilipemic drugs should be considered in use for the children with SRINS.

Receptor specificity in the self-renewal and differentiation of primary multipotential hemopoietic cells

To determine whether cytokine-induced signals generate unique responses in multipotential hemopoietic progenitor cells, the signaling domains of 3 different growth factor receptors (Mpl, granulocyte-colony-stimulating factor [G-CSF] receptor, and Flt-3) were inserted into mouse primary bone marrow cells. To circumvent the activation of endogenous receptors, each signaling domain was incorporated into an FK506 binding protein (FKBP) fusion to allow for its specific activation using synthetic FKBP ligands. Each signaling domain supported the growth of Ba/F3 cells; however, only Mpl supported the sustained growth of transduced marrow cells, with a dramatic expansion of multipotential progenitors and megakaryocytes. These findings demonstrate that the self-renewal and differentiation of multipotential progenitor cells can be influenced through distinct, receptor-initiated signaling pathways.

Metabolism of S-nitrosoglutathione by endothelial cells

S-nitrosoglutathione (GSNO) is an inhibitor of platelet aggregation and has also been shown to protect the ischemic heart from reperfusion-mediated injury. Although GSNO is often used in cell culture as a source of nitric oxide, the mechanisms of GSNO metabolism are not well established. We show here that GSNO decomposition by bovine aortic endothelial cells has an absolute dependence on the presence of cystine in the cell culture medium. In addition, GSNO decay is inhibited by diethyl maleate, an intracellular glutathione scavenger, but not by buthionine sulfoximine, a glutathione synthesis inhibitor. This indicates that thiols in general, rather than specifically glutathione, are the major factors that influence GSNO decay. Only 40% of the nitroso group of GSNO could be recovered as nitrite/nitrate, suggesting that the primary route of GSNO decay is reductive and that nitric oxide is only a minor product of GSNO decay. We conclude that the intracellular thiol pool causes the reduction of extracellular disulfides to thiols, which then directly reduce GSNO.

[Quantitative determination of icariin in "tangzhi shuangjiang cha" by high performance liquid chromatography]

Icariin in "Tangzhi Shuangjiang Cha" was quantitatively determined by HPLC with ODS column, a mixture of MeOH-H2O(60:40, V/V) as mobile phase and UV detection at 270 nm. There was a good linear relationship within the range of 0.1 g/L-0.5 g/L(r = 0.9993). The average recovery was 101.4%, RSD was below 2.7%(n = 3). The method is rapid, simple, accurate and reproducible. And the method is proposed to be used for quality control of "Tangzhi Shuangjiang Cha".

[Determination of salicylic acid, resorcinol and chloramphenicol in junlieping tincture by reversed-phase high performance liquid chromatography]

A reversed-phase high performance liquid chromatographic method was developed for the quantitative determination of salicylic acid, resorcinol and chloramphenicol in Junlieping tincture. The operation was carried out on an ODS column with the mobile phase of a mixture of acetonitrile-methanol-water(25:10:65, volume proportion). The eluate was detected at 278 nm wavelength. This method is simple, fast and can be used for the quality control of Junlieping tincture.

The solution structure of the complex formed between alpha-bungarotoxin and an 18-mer cognate peptide derived from the alpha 1 subunit of the nicotinic acetylcholine receptor from Torpedo californica

The region encompassing residues 181-98 on the alpha1 subunit of the muscle-type nicotinic acetylcholine receptor forms a major determinant for the binding of alpha-neurotoxins. We have prepared an (15)N-enriched 18-amino acid peptide corresponding to the sequence in this region to facilitate structural elucidation by multidimensional NMR. Our aim was to determine the structural basis for the high affinity, stoichiometric complex formed between this cognate peptide and alpha-bungarotoxin, a long alpha-neurotoxin. Resonances in the complex were assigned through heteronuclear and homonuclear NMR experiments, and the resulting interproton distance constraints were used to generate ensemble structures of the complex. Thr(8), Pro(10), Lys(38), Val(39), Val(40), and Pro(69) in alpha-bungarotoxin and Tyr(189), Tyr(190), Thr(191), Cys(192), Asp(195), and Thr(196) in the peptide participate in major intermolecular contacts. A comparison of the free and bound alpha-bungarotoxin structures reveals significant conformational rearrangements in flexible regions of alpha-bungarotoxin, mainly loops I, II, and the C-terminal tail. Furthermore, several of the calculated structures suggest that cation-pi interactions may be involved in binding. The root mean square deviation of the polypeptide backbone in the complex is 2.07 A. This structure provides, to date, the highest resolution description of the contacts between a prototypic alpha-neurotoxin and its cognate recognition sequence.

Diabetes mellitus and exocrine pancreatic dysfunction in perk-/- mice reveals a role for translational control in secretory cell survival

The protein kinase PERK couples protein folding in the endoplasmic reticulum (ER) to polypeptide biosynthesis by phosphorylating the alpha subunit of eukaryotic translation initiation factor 2 (eIF2alpha), attenuating translation initiation in response to ER stress. PERK is highly expressed in mouse pancreas, an organ active in protein secretion. Under physiological conditions, PERK was partially activated, accounting for much of the phosphorylated eIF2alpha in the pancreas. The exocrine and endocrine pancreas developed normally in Perk-/- mice. Postnatally, ER distention and activation of the ER stress transducer IRE1alpha accompanied increased cell death and led to progressive diabetes mellitus and exocrine pancreatic insufficiency. These findings suggest a special role for translational control in protecting secretory cells from ER stress.

Magnetic and structural properties of electrochemically self-assembled Fe1-xCox nanowires

Fe1-xCox (0 < or = x < or = 1) nanowires have been self-assembled by electrodeposition in porous alumina films. The crystal structure is bee at the Fe end. With increased addition of Co, the crystal structure remains bcc until about 67% addition of Co. At the Co end, the structure is a mixture of hcp and fcc. Magnetic studies show very high coercivities for the Fe-Co alloys in the bcc phase. For Fe0.67Co0.33 nanowires of diameter 9 nm, the coercivity is about 2900 Oe, whereas for Fe0.33Co0.67 nanowires, it is about 2850 Oe. Temperature and size dependence of magnetic properties show no indication of superparamagnetic effects down to wire diameters of 9 nm.

Vascular permeability factor (VPF)/vascular endothelial growth factor (VEGF) peceptor-1 down-modulates VPF/VEGF receptor-2-mediated endothelial cell proliferation, but not migration, through phosphatidylinositol 3-kinase-dependent pathways

Vascular permeability factor (VPF)/vascular endothelial growth factor (VEGF) achieves its multiple functions by activating two receptor tyrosine kinases, Flt-1 (VEGF receptor-1) and KDR (VEGF receptor-2), both of which are selectively expressed on primary vascular endothelium. To dissect the respective signaling pathways and biological functions mediated by these receptors in primary endothelial cells with these two receptors intact, we developed a chimeric receptor system in which the N terminus of the epidermal growth factor receptor was fused to the transmembrane domain and intracellular domain of KDR (EGDR) and Flt-1 (EGLT). We observed that KDR, but not Flt-1, was responsible for VPF/VEGF-induced human umbilical vein endothelial cell (HUVEC) proliferation and migration. Moreover, Flt-1 showed an inhibitory effect on KDR-mediated proliferation, but not migration. We also demonstrated that the inhibitory function of Flt-1 was mediated through the phosphatidylinositol 3-kinase (PI-3K)-dependent pathway because inhibitors of PI-3K as well as a dominant negative mutant of p85 (PI-3K subunit) reversed the inhibition, whereas a constitutively activated mutant of p110 introduced the inhibition to HUVEC-EGDR. We also observed that, in VPF/VEGF-stimulated HUVECs, the Flt-1/EGLT-mediated down-modulation of KDR/EGDR signaling was at or before intracellular Ca(2+) mobilization, but after KDR/EGDR phosphorylation. By mutational analysis, we further identified that the tyrosine 794 residue of Flt-1 was essential for its antiproliferative effect. Taken together, these studies contribute significantly to our understanding of the signaling pathways and biological functions triggered by KDR and Flt-1 and describe a unique mechanism in which PI-3K acts as a mediator of antiproliferation in primary vascular endothelium.

Reciprocal expression of CD38 and CD34 by adult murine hematopoietic stem cells

The effects of activation of adult murine stem cells on their expression of CD38 were studied using a murine transplantation model. First, the published finding that the majority of long-term engrafting cells from normal adult steady-state marrow are CD38(+) was confirmed. Next, it was determined that the majority of stem cells activated in vivo by injection of 5-fluorouracil (5-FU) or mobilized by granulocyte colony-stimulating factor are CD38(-). Stem cells that were activated in culture with interleukin-11 and steel factor were also CD38(-). Previous studies have shown that expression of CD34 by adult stem cells is also modulated by in vivo or in vitro activation. To determine whether there is reciprocal expression of CD38 and CD34, 4 populations of post-5-FU marrow cells were analyzed. The majority of the stem cells were in the CD38(-)CD34(+) fraction. However, secondary transplantation experiments indicated that when the bone marrow reaches steady state, the majority of the stem cells become CD38(+)CD34(-). In addition, the minority populations of CD34(+) stem cells that occur in steady-state bone marrow are CD38(-). This reversible and reciprocal expression of CD38 and CD34 by murine stem cells may have implications for the phenotypes of human stem cells.

Sequence Specificity of Hydrogen-Bonded Molecular Duplexes

Hydrogen-bonded molecular duplexes, 1.3 and 1.4, each of which contains a mismatched binding site (acceptor-to-acceptor in 1.3, and donor-to-donor in 1.4), were designed and synthesized based on duplex 1.2. One- and two-dimensional NMR studies demonstrated that, despite their single mismatched binding sites, the backbones of duplexes 1.3 and 1.4 still stayed in register through the formation of the remaining five H-bonds. The backbones of 1.3 and 1.4 adjusted to the presence of the mismatched binding sites by slightly twisting around these sites, which alleviate any head-on repulsive interactions between two H-bond donors (amide O) or between two acceptors (amide H). After 1 equiv of single strand 2, which forms a perfectly matched duplex 1.2 with single strand 1, was added into the solution of either 1.3 or 1.4, only 1.2 and single strand 3 or 4, were detected. Isothermal titration calorimetry (ITC, in chloroform containing 5% DMSO) indicated that duplexes 1.3 and 1.4 were significantly (>40 times) less stable than the corresponding perfectly hydrogen-bonded duplex 1.2. These NMR and ITC results indicate that the pairing of two complementary single strands is not affected by another very similar single strand that contains only one wrong H-bond donor or acceptor, which demonstrates that the self-assembly of this class of H-bonded duplexes is a highly sequence-specific process. The role of these H-bonded duplexes as predictable and programmable molecular recognition units for directing intermolecular interactions has thus been established.

Cell surface glypicans are low-affinity endostatin receptors

Endostatin, a collagen XVIII fragment, is a potent anti-angiogenic protein. We sought to identify its endothelial cell surface receptor(s). Alkaline phosphatase- tagged endostatin bound endothelial cells revealing two binding affinities. Expression cloning identified glypican, a cell surface proteoglycan as the lower-affinity receptor. Biochemical and genetic studies indicated that glypicans' heparan sulfate glycosaminoglycans were critical for endostatin binding. Furthermore, endostatin selected a specific octasulfated hexasaccharide from a sequence in heparin. We have also demonstrated a role for endostatin in renal tubular cell branching morphogenesis and show that glypicans serve as low-affinity receptors for endostatin in these cells, as in endothelial cells. Finally, antisense experiments suggest the critical importance of glypicans in mediating endostatin activities.

[Purification and properties of neutral phytase form Bacillus subtilis]

A strain Bacillus subtilis producing neutral phytase was screened from soil. The protein of phytase was purified by HPLC. Optimal pH value and temperature of the phytase for its activity were 7.5 and 55 degrees C, respectively. The Km values of the phytase for dodecasodium phytate under 37 degrees C was 0.19 mmol/L. The molecule weight of the phytase protein was determined as about 45 kD by SDS-PAGE. The N-terminal amino acids sequence of the phytase protein was determined as Lys-His-Lys-Leu-Ser-Asp-Pro-Tyr-His-Phe-Thr by amino acids sequence analysis.

[The fluorescent properites of the complexes of 1,3-diphenyl-4-acyl-5-pyrazolones with Eu(III)]

The binary and ternary Eu(III) complexes have been prepared with four 1,3-diphenyl-4-acyl-5-pyazolones as ligands (where the four acyls are benzoyl, phenylacetyl, butyryl and choroacetyl, and the compounds are represented by DPBZP, DPPAP, DPBTP, DPCAP respectively). The composition of the complexes was determined by chemical and elementary analysis, and the structure of the complexes was characterized by FTIR spectra. The fluorescence spectra of the complexes were measured. It is indicated that the complexes emit with the characteristic fluorescence of Eu(III), the fluorescence intensity of the complexes are closely related to the substituents at the acyl at 4-position in pyrazolone ring of the ligands, depending on the ligands, the descending order of the fluorescence intensity is DPBZP > DPPAP > DPBTP > DPCAP, and that the second ligand, 1, 10-phenanthroline, remarkably intensifies the fluorescence of the complexes.

[A study of methicillin -- resistant staphylococcus aureus (MRSA) in a burn unit with repetitive -- DNA -- sequence -- based PCR fingerprinting]

OBJECTIVE

To investigate the distribution and spread of MRSA in a burn ward, so as to explore the measures of the prevention, surveillance and control of hospital infection in a burn ward.

METHODS

Five hundred and four specimens were isolated from the wounds and nasal vestibules of burn patients, the hands and nasal vestibules of medical staffs and lay attendants and the surfaces of various equipments. From these specimens, 58 strains of MRSA and 43 methicillin -- sensitive staphylococcus aureus (MSSA) were isolated. The genome DNA of isolated MRSA strains was analyzed by repetitive DNA -- sequence -- based PCR analysis.

RESULTS

MRSA strains were isolated from the burn wounds in 22 of 41 (53.7%) patients, and 5 from the nasal vestibules. Moreover, among 19 medical staffs, MRSA strains were isolated from the hands of 9 persons, but not from the nasal vestibules. From the hands in 9 of 43 lay attendants and the nasal vestibules in 2 MRSA strains were found. Thirteen MRSA strains were isolated from 193 specimens from the surrounding items. It was indicated by repetitive DNA -- sequence -- based PCR analysis of the genome DNA of isolated MRSA strains that there existed homologous strains around the patients' wounds, in the burn wounds, on the skin of medical staffs and lay attendants and also surrounding equipments.

CONCLUSION

(1) There was wide spread presence of MRSA homologous strains in the burn ward. (2) It was indicated by repetitive DNA -- sequence -- based PCR analysis of the genome DNA of isolated MRSA strains that there was cross infection among burn patients. The source of the infection of MRSA in burn ward was burn patients, and the route of the infection was hands of medical staffs and lay attendants. (3) MRSA is wide -- spread. The contamination of the hands and the environment was potential risk factor of MRSA outbreak in the burn unit.

[Diagnosing complicated congenital heart disease with two-dimensional echocardiography and three-segment concept]

OBJECTIVE

To apply three-segment heart anatomy concept to two-dimensional echocardiography (2DE) in the diagnosis of complicated congenital heart disease (CHD).

METHODS

920 cases of CHD were diagnosed with 2DE and three-segment heart anatomy concept. 822 out of the 920 cases underwent angiocardiography, and 584 cases were confirmed by operation.

RESULTS

According to three-segment heart anatomy concept of atrial position, 855 cases were situs solitus (including 89 cases of left superior vena cava and 31 cases of complete anomalous pulmonary venous drainage), 53 cases were situs inversus, and 12 cases were situs ambigus. As to atrial-ventricular valve, 747 cases were both opening, 112 cases had one-side atresia, and 61 cases had one together valve; As to ventricle position, 606 cases were dextro-loop, 111 cases had levo-loop, and 203 cases had single ventricle (including 24 cases), As to cor biloculare of great artery relation, 304 cases had normal relation of great arteries, including 35 cases of pulmonary atresia, 219 cases had right-transposition of great arteries, 240 cases had left-transposition of great arteries, 32 cases were mirror to normal, and 25 cases had persistent truncus arteriosus. 823 cases were diagnosed with 2DE, with a total accurate rate of 89.5%.

CONCLUSION

Applying three-segment heart anatomy concept to 2DE to diagnose complicated CHD and analyzing the heart segment by segment will make the diagnosis simple and systematic, providing a concise basis for heart surgeries.

The role of the hinge region of the luteinizing hormone receptor in hormone interaction and signal generation

Luteinizing hormone receptor, a G protein-coupled receptor, consists of two halves, the N-terminal extracellular hormone binding domain (exodomain) and the C-terminal membrane-associated, signal-generating domain (endodomain). The exodomain has seven to nine Leu-rich repeats, which are generally thought to form a 1/3 donut-like structure and interact with human choriogonadotropin (hCG). The resulting hCG-exodomain complex adjusts the structure and its association with the endodomain, which results in signal generation in the endodomain. It is unclear whether the rigid 1/3 donut structure could provide the agility and versatility of this dynamic action. In addition, there is no clue as to where the endodomain contact point (the signal modulator) in the exodomain is. To address these issues, the exodomain was examined by Ala scan and multiple substitutions, while receptor peptides were used for photoaffinity labeling and affinity cross-linking. Our results show that the C-flanking sequence (hinge region), Thr(250)-Gln(268), of the Leu-rich repeats (LRRs) specifically interacts with hCG, preferentially hCGalpha. This interaction is inhibited by exoloop 2 of the endodomain but not by exoloops 1 and 3, suggesting an intimate relationship between Thr(250)-Gln(268), exoloop 2, and hCG. Taken together, our observations in this article suggest a new paradigm that the LRRs contact the front of hCG, while both flanking regions of the LRRs interact with the sides of hCG. This would trap hCG in the 1/3 donut structure of the LRRs and enhance the binding affinity. In addition, mutations of conserved Ser(255) in the sequence can constitutively activate the receptor. This provides a clue for the signal modulator in the exodomain. In contrast, a phenyl or phenolic group is necessary at conserved Tyr(253) for targeting the receptor to the surface.

[Fluorescence spectra of the rare earth complex-PAA-g-PE films]

The acrylic acid (AA) was grafted onto the PE film surface through UV photograft polymerization. With certain pH value, the grafted films were made to react with the alcohol-water solution of Eu3+ and alpha-thenoyltrifluoroacetone (TTA) or with the chloroform-water solution of Tb3+ and acetyl actone (AcAc), thus causing the preparation of the red or green fluorescent films. As compared with the corresponding Eu(TTA)3.(H2O)2 or Tb(AcAc)3.(H2O)2 solid complexes, both the excitation and emission spectra of the fluorescent films changed remarkably. It's predictable that chemical bond combination has occurred between the rare earth complexes and the macromolecular material. In addition, the IR spectra of the fluorescent films were also observed.

Nicotine and amyloid formation

The major protein constituents of amyloid deposits in Alzheimer's disease (AD) are the 40-residue beta-amyloid (Abeta) (1-40) peptide and the 42-residue Abeta(1-42) peptide. The Abeta(1-42) is more pathogenic and produced in greater quantities in familial forms of AD. A major goal of research is to uncover a suitable inhibitor that either slows down or inhibits Abeta formation (beta-amyloidosis). During beta-amyloidosis, structural changes associated with the conversion of monomeric Abeta peptide building blocks into the aggregated fibrillar beta-sheet structures occur (alpha-helix-->beta-sheet or random, extended chain-->beta-sheet). In previous work, we and others established that nicotine, a major component of cigarette smoke, inhibits beta-amyloidosis of the Abeta(1-42), which may result from nicotine binding to the alpha-helical structure. These conclusions were based on solution nuclear magnetic resonance (NMR) spectroscopic studies with the nonnative 28-residue Abeta(1-28). This information suggests that, when administered therapeutically to AD patients, nicotine may not only affect cholinergic activation, but could also conceivably alter amyloid deposition. In this report, NMR studies were augmented with the naturally occurring Abeta(1-42), under conditions where the peptide folds into a predominantly alpha-helical or random, extended chain structure. The major result is that nicotine shows only modest binding to these conformations, indicating that the nicotine inhibition to beta-amyloidosis probably results from binding to a small, soluble beta-sheet aggregate that is NMR invisible.

Analysis of the structure and expression pattern of MRP7 (ABCC10), a new member of the MRP subfamily

The MRP subfamily of ABC transporters currently consists of at least six members, several of which have been demonstrated to transport amphipathic anions and to confer in vitro resistance to chemotherapeutic agents. In searching the data bases we identified the product of a cDNA sequencing project that bears significant similarity to MRP subfamily transporters. In this report the predicted coding sequence, protein product and expression pattern of this cDNA, termed MRP7, are analyzed. The MRP7 cDNA sequence encodes a 1492 amino acid ABC transporter whose structural architecture resembles that of MRP1, MRP2, MRP3, and MRP6, in that its transmembrane helices are arranged in three membrane spanning domains. However, in contrast to the latter transporters, a conserved N-linked glycosylation site is not found at the N-terminus of MRP7. Comparisons of the MRP7 amino acid sequence indicated that while it is most closely related to other MRP subfamily members, its degree of relatedness is the lowest of any of the known MRP-related transporters. The integrity of the predicted MRP7 coding sequence was confirmed by the synthesis of an approximately 158 kDa protein in reticulocyte lysates programmed with the MRP7 cDNA. While MRP7 transcript was detected in a variety of tissues by RT/PCR, it was not readily detectable by RNA blot analysis, suggesting that it is expressed at low levels in these tissues. Fluorescence in situ hybridization indicated that MRP7 maps to chromosome 6p12-21, in proximity to several genes associated with glutathione conjugation and synthesis. On the basis of these findings and evolutionary cluster analysis, we conclude that MRP7 is a member of the MRP subfamily of amphipathic anion transporters.

High-speed liquid chromatography/tandem mass spectrometry using a monolithic column for high-throughput bioanalysis

With the ever-increasing workload from a variety of in vitro and in vivo screening procedures, new analytical methodologies to perform bioanalysis in an accurate and high-throughput manner are in great demand. In this work, monolithic columns were used instead of conventional particulate HPLC columns to perform chromatographic separations. Because the pressure drop on a monolithic column was considerably lower than that on a particulate column, a high flow rate (6 mL/min) was used for a 4.6 x 50 mm monolithic column with a total backpressure of about 61 bar measured using acetonitrile/water (50:50). The capability of using a regular column length at high flow rates, combined with the extremely small dependency of separation efficiency on linear flow velocity, allowed for the generation of sufficient chromatographic resolving power in a significantly reduced runtime. As demonstrated in this work, a plasma extract of a mixture of tempazepam, tamoxifen, fenfluramine, and alprozolam were baseline separated within a total analysis time of one minute. An average peak width at half maximum of approximately one second was noted using a generic broad gradient. It was also found that the separation efficiency and signal/noise (S/N) ratios for this separation remained almost constant at flow rates of 1, 3, and 6 mL/min, respectively. The ruggedness of the separation was evaluated by injecting 600 plasma extracts containing the replicates of a standard curve of the above mixture during an overnight run. The chromatographic retention time, separation quality, peak response and sensitivity were highly reproducible throughout the run. This high-speed liquid chromatography/tandem mass spectrometry (LC/MS/MS) system has been used routinely in the authors' laboratory to support drug discovery programs.

Induction of heme oxygenase-1 by Ginkgo biloba extract but not its terpenoids partially mediated its protective effect against lysophosphatidylcholine-induced damage

In this study, we examined whether Ginkgo Biloba Extract and its terpenoid constituents protect against oxidative stress through actions on heme oxygenase (HO) gene expression and activity. HO-1 and glutathione peroxidase (GPx) gene expressions were examined by reverse transcription polymerase chain reaction (RT-PCR) analysis, HO activity and GPx enzyme activity were analysed by spectrophotometric assay. Pretreatment of H9c2 myocytes with 100-500 microgml(-1)Ginkgo Biloba Extract caused induction of HO-1 gene expression and a significant increase in HO activity; 30 microgml(-1)ginkgolide B and 30 microgml(-1)bilobalide had little effect. Treatment with Ginkgo Biloba Extract for 24 h also significantly increased GPx gene expression and GPx enzyme activity. Pretreatment with Ginkgo Biloba Extract, ginkgolide B and bilobalide protected myocytes against lysophosphatidylcholine (LPC)-induced damage. The protective effect of Ginkgo Biloba Extract against LPC-induced damage was partially suppressed by a HO inhibitor, Zinc protoporphyrin-IX (ZnPP-IX), while ZnPP-IX did not suppress the protective effect of ginkgolide B or bilobalide. Furthermore, pretreatment with hemin, biliverdin or bilirubin reduced cytotoxicity induced by LPC. These results suggest that induction of HO-1 by Ginkgo Biloba Extract but not its terpenoid constituents may play a beneficial role in oxidative stress. The mechanism of Ginkgo Biloba Extract-induced HO-1 gene expression and the increase in HO activity may be related to alteration of intracellular glutathione levels.

Characterization of phosphopeptides from protein digests using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and nanoelectrospray quadrupole time-of-flight mass spectrometry

A two-step mass spectrometric method for characterization of phosphopeptides from peptide mixtures is presented. In the first step, phosphopeptide candidates were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) based on their higher relative intensities in negative ion MALDI spectra than in positive ion MALDI spectra. The detection limit for this step was found to be 18 femtomoles or lower in the case of unfractionated in-solution digests of a model phosphoprotein, beta-casein. In the second step, nanoelectrospray tandem mass (nES-MS/MS) spectra of doubly or triply charged precursor ions of these candidate phosphopeptides were obtained using a quadrupole time-of-flight (Q-TOF) mass spectrometer. This step provided information about the phosphorylated residues, and ruled out nonphosphorylated candidates, for these peptides. After [(32)P] labeling and reverse-phase high-performance liquid chromatography (RP-HPLC) to simplify the mixtures and to monitor the efficiency of phosphopeptide identification, we used this method to identify multiple autophosphorylation sites on the PKR-like endoplasmic reticulum kinase (PERK), a recently discovered mammalian stress-response protein.

Multiple-sprayer tandem mass spectrometry with parallel high flow extraction and parallel separation for high-throughput quantitation in biological fluids

In this work, an on-line four-column high-flow parallel extraction device was set up and interfaced to a four-column parallel separation system with a four-sprayer tandem mass spectrometric detector. This system allowed for the direct and simultaneous sampling, extraction, separation, and detection of four samples in biological fluids, resulting in significantly increased throughput. The performance of this system was evaluated using rat plasma samples spiked with methotrexate as a test compound. The results showed that the relative standard deviation for responses across the four parallel channels was less than 10% for a concentration range from 10 to 2500 nM, resulting in comparable sensitivity (slope of curve) for the analyte on all channels. A ruggedness test was performed using a mixed set of new and used extraction columns and the relative standard deviation in analyte response was found to be below 15%. The inter-channel crosstalk was measured to be about 0.1%. A comparison between the data generated on this system and on a conventional system for a rat pharmacokinetic study showed no more than 20% difference in measured concentrations. This parallel system is a viable tool for high-throughput bioanalysis in a drug discovery environment.

Total syntheses of (-)-fumiquinazolines A, B, and I

[structure] The first total syntheses of (-)-fumiquinazolines A, B, and I have been accomplished efficiently using the Pd-catalyzed cyclization of an iodoindole carbamate to construct the imidazoindolone moiety and the dehydrative cyclization of a diamide followed by rearrangement through an amidine to construct the quinazolone moiety.

[Studies on chemical components of the volatile oil from the leaves of Hypericum perforatum]

OBJECTIVE

To determine the volatile oil of the leaves from Hypericum perforatum L..

METHOD

The essential oil was obtained by simultaneous distillation and solvent extraction. The chemical components were seperated and identified by GC-MS. The relative contents in the volatile oil were determined by area nomalization.

RESULTS

54 chemical constituents were separated and identified representing 92.32% of the total contents.

CONCLUSION

Sesquiterpenes are major chemical constituents in the oil from the leaves of Hypericum perforatum L.. They are very different from those of the essential oil from the same species from the other country.

Reaction of S-nitrosoglutathione with the heme group of deoxyhemoglobin

The mechanism of interaction between S-nitrosoglutathione (GSNO) and hemoglobin is a crucial component of hypotheses concerning the role played by S-nitrosohemoglobin in vivo. We previously demonstrated (Patel, R. P., Hogg, N., Spencer, N. Y., Kalyanaraman, B., Matalon, S., and Darley-Usmar, V. M. (1999) J. Biol. Chem. 274, 15487-15492) that transnitrosation between oxygenated hemoglobin and GSNO is a slow, reversible process, and that the reaction between GSNO and deoxygenated hemoglobin (deoxyHb) did not conform to second order reversible kinetics. In this study we have reinvestigated this reaction and show that GSNO reacts with deoxyHb to form glutathione, nitric oxide, and ferric hemoglobin. Nitric oxide formed from this reaction is immediately autocaptured to form nitrosylated hemoglobin. GSNO reduction by deoxyHb is essentially irreversible. The kinetics of this reaction depended upon the conformation of the protein, with more rapid kinetics occurring in the high oxygen affinity state (i.e. modification of the Cysbeta-93) than in the low oxygen affinity state (i.e. treatment with inositol hexaphosphate). A more rapid reaction occurred when deoxymyoglobin was used, further supporting the observation that the kinetics of reduction are directly proportional to oxygen affinity. This observation provides a mechanism for how deoxygenation of hemoglobin/myoglobin could facilitate nitric oxide release from S-nitrosothiols and represents a potential physiological mechanism of S-nitrosothiol metabolism.

Topical photodynamic therapy with 5-aminolaevulinic acid does not induce hair regrowth in patients with extensive alopecia areata

BACKGROUND

Photodynamic therapy (PDT) is a new modality involving the administration of a photosensitizer, or photosensitizer precursor, followed by its activation with light to generate a therapeutic effect. 5-Aminolaevulinic acid (ALA) is a photosensitizer precursor that is transformed by cells into protoporphyrin IX (PpIX), which can in turn be activated by red light.

OBJECTIVES

To investigate the effect of PDT in alopecia areata (AA).

METHODS

In six patients with extensive AA, topical ALA lotion at 5%, 10% and 20% as well as the vehicle lotion alone were applied separately to different scalp areas, followed 3 h later by exposure to red light at each treatment session.

RESULTS

No significant hair growth was observed after 20 twice-weekly treatment sessions. A significant increase in erythema and pigmentation was observed for the three concentrations of ALA lotion vs. the vehicle, implying that a phototoxic PDT effect was achieved in the skin. In vivo fluorescence spectroscopy in one patient showed an increase in red PpIX fluorescence 3 h after ALA application followed by a decrease after light exposure. On fluorescence microscopy, bright red fluorescence was present in the epidermis and sebaceous glands, but not in the inflammatory infiltrate surrounding the hair follicle following ALA application.

CONCLUSIONS

PDT was ineffective in the treatment of AA.

Cloning, sequencing, and function of sanF: A gene involved in nikkomycin biosynthesis of Streptomyces ansochromogenes

A 111-bp DNA fragment related to nikkomycin biosynthesis of Streptomyces ansochromogenes 7100 was obtained with the method of reverse genetics. Then, a 2.2-kb DNA fragment was cloned from the DNA library of S. ansochromogenes 7100 by using the 111-bp fragment as a probe. Sequence analysis showed that the fragment contains one complete open reading frame (ORF) that encodes a 219-amino acid (aa) protein, and this gene was designated sanF (GenBank Accession No. AF223971). The function of the sanF gene was studied by a strategy of gene disruption, and the resulting sanF mutants lost the ability to synthesize biologically active nikkomycin, indicating that sanF is essential for nikkomycin biosynthesis.

Regulated translation initiation controls stress-induced gene expression in mammalian cells

Protein kinases that phosphorylate the alpha subunit of eukaryotic initiation factor 2 (eIF2alpha) are activated in stressed cells and negatively regulate protein synthesis. Phenotypic analysis of targeted mutations in murine cells reveals a novel role for eIF2alpha kinases in regulating gene expression in the unfolded protein response (UPR) and in amino acid starved cells. When activated by their cognate upstream stress signals, the mammalian eIF2 kinases PERK and GCN2 repress translation of most mRNAs but selectively increase translation of Activating Transcription Factor 4 (ATF4), resulting in the induction of the downstream gene CHOP (GADD153). This is the first example of a mammalian signaling pathway homologous to the well studied yeast general control response in which eIF2alpha phosphorylation activates genes involved in amino acid biosynthesis. Mammalian cells thus utilize an ancient pathway to regulate gene expression in response to diverse stress signals.

[Infrared spectra and Raman spectra of monoclinic RblnS2 and CsInS2]

Monoclinic RbInS2 and CsInS2 were prepared by the traditional flux method and their IR and Raman spectra were studied. The IR and Raman absorption bands of CsInS2 shift to lower frequency compared with RbInS2. IR and Raman spectra show that monoclinic RbInS2 and CsInS2 exhibit good infrared transmission.

[A clinicopathological study of hepatic focal nodular hyperplasia]

OBJECTIVE

To study the clinicopathological features of focal nodular hyperplasia (FNH).

METHODS

The clinicopathological characteristics of 25 cases of FNH were studied retrospectively. 20 cases followed for 6 to 47 months. All were evaluated by use of paraffin-embedded sections, special and immunohistochemical staining (EnVision method) and electron microscope.

RESULTS

17 female and 8 male FNH patients aged 14 to 58 (median 38) years of age, all alpha-fetoprotein negative, asymptomatic and normal biochemical liver tests in most cases. The macroscopic hallmark is a central stellate fibrotic scar, composed of fibrous connective tissue and tortuous blood vessels, the fibrous tissue radiated peripherally, dividing the mass into multiple, variably sized nodules, simulating the pattern of cirrhosis. Microscopically, multinodular proliferation of benign-appearing hepatocytes separated by bile-duct-containing fibrous septae that radiate from the central scar. Internodular bile duct proliferation is abundant and merge imperceptibly with the hepatocyte elements near the fibrous septa. Immunohistochemically, the keratin expessed by hepatocytes and by the proliferated bile ducts were similar. Electron microscopic examination found that the ultrastructure of tumor cells were similar to normal hepatocytes. 20 cases were followed for 6-47 months, all survived with no recurrence.

CONCLUSION

FNH is a benign hepatocytic lesion, i.e. a reactive proliferation of hepatic cells to local blood vessel anomalies.

Transport of amphipathic anions by human multidrug resistance protein 3

The multidrug resistance-associated protein 1 (MRP1) and the canalicular multispecific organic anion transporter (cMOAT or MRP2) are ATP-binding cassette transporters that confer resistance to some anticancer drugs and efflux glutathione and glucuronate conjugates from the cell. The MRP subfamily of ABC transporters, however, contains at least four other members of which MRP3 (MOAT-D) bears the closest structural resemblance to MRP1. Although transfection studies have established that human MRP3 confers increased resistance to several anticancer agents, neither the substrate selectivity nor physiological functions of this transporter have been determined. Here we report the results of investigations of the in vitro transport properties of cloned human MRP3 using membrane vesicles prepared from MRP3-transfected HEK293 cells. It is shown that the expression of MRP3 is specifically associated with enhancement of the MgATP-dependent transport into membrane vesicles of the glucuronide estradiol 17-beta-D-glucuronide (E(2)17betaG), the glutathione conjugates 2,4-dinitrophenyl S-glutathione (DNP-SG) and leukotriene C4 (LTC4), the antimetabolite methotrexate, and the bile acid glycocholate. DNP-SG, LTC4, and E(2)17betaG are transported at moderate affinity and low capacity with Km and Vmax values of 5.7 +/- 1.7 microM and 3.8 +/- 0.1 pmol/mg/min, 5.3 +/- 2.6 microM and 20.2 +/- 5.9 pmol/mg/min, and 25.6 +/- 5.4 microM and 75.6 +/- 5.9 pmol/mg/min, respectively. Methotrexate and glycocholate are transported at low affinity and high capacity with Km and Vmax values of 776 +/- 319 microM and 288 +/- 54 pmol/mg/min and 248 +/- 113 microM and 183 +/- 34 pmol/mg/min, respectively. On the basis of these findings, the osmotic dependence of the transport measured and its inability to transport taurocholate, MRP3, like MRP1 and cMOAT, is concluded to be competent in the transport of glutathione S-conjugates, glucuronides, and methotrexate, albeit at low to moderate affinity. In contrast to MRP1, cMOAT, and all other characterized mammalian ABC transporters, however, MRP3 is active in the transport of the monoanionic human bile constituent glycocholate.

[Improvement of pulse waveform detection with autoregressive model in blood oxygen saturation measurement]

Blood oxygen saturation is an important physiological parameter of human body. The accurate measurement of it is important to both physiological research and medical application. Dual-wavelength method is widely adopted in nonivasive detection of blood oxygen saturation. In this method, the calculation of blood oxygen saturation is based on the identification of pulse waveform and the extraction of peak characteristic values. But the pulse waveform obtained from this method merely has distinctive features such as the QRS complexes in ECG, so the ratio of correct detection of pulse waveform is always low. An autoregressive model of heart-beat intervals is developed. The output of the differential method is compared with that of the AR model so as to distinguish the false or missing detection. The ratio of correct detection is improved by the use of this method.

Prokaryotic regulation of epithelial responses by inhibition of IkappaB-alpha ubiquitination

Epithelia of the vertebrate intestinal tract characteristically maintain an inflammatory hyporesponsiveness toward the lumenal prokaryotic microflora. We report the identification of enteric organisms (nonvirulent Salmonella strains) whose direct interaction with model human epithelia attenuate synthesis of inflammatory effector molecules elicited by diverse proinflammatory stimuli. This immunosuppressive effect involves inhibition of the inhibitor kappaB/nuclear factor kappaB (IkappaB/NF-kappaB) pathway by blockade of IkappaB-alpha degradation, which prevents subsequent nuclear translocation of active NF-kappaB dimer. Although phosphorylation of IkappaB-alpha occurs, subsequent polyubiquitination necessary for regulated IkappaB-alpha degradation is completely abrogated. These data suggest that prokaryotic determinants could be responsible for the unique tolerance of the gastrointestinal mucosa to proinflammatory stimuli.

In vivo selection using a cell-growth switch

A major obstacle to stem-cell gene therapy rests in the inability to deliver a gene into a therapeutically relevant fraction of stem cells. One way to circumvent this obstacle is to use selection. Vectors containing two linked genes serve as the basis for selection, with one gene encoding a selectable product and the other, a therapeutic protein. Applying selection in vivo has the potential to bring a minor population of genetically corrected cells into the therapeutic range. But strategies for achieving in vivo selection have traditionally relied on genes that confer resistance to cytotoxic drugs and are encumbered by toxicity. Here we describe a new system for in vivo selection that uses a 'cell-growth switch', allowing a minor population of genetically corrected cells into the therapeutic range. But strategies for achieving in vivo selection have traditionally relied on genes that confer resistance to cytotoxic drugs and are encumbered by toxicity. Here we describe a new system for in vivo selection that uses a 'cell-growth switch', allowing a minor population of genetically modified cells to be inducibly amplified, thereby averting the risks associated with cytotoxic drugs. This system provides a general platform for conditionally expanding genetically modified cell populations in vivo, and may have widespread applications in gene and cell therapy.

Retinoic acid selectively inhibits the vascular permeabilizing effect of VPF/VEGF, an early step in the angiogenic cascade

All-trans-retinoic acid (RA) and other retinoids modulate cell growth and differentiation, generally favoring terminal cell differentiation and inhibiting carcinogenesis. Retinoids are also reported to inhibit angiogenesis and endothelial cell migration, actions that are also anti-carcinogenic. Vascular permeability factor/vascular endothelial growth factor (VPF/VEGF) is a multifunctional cytokine secreted by many tumors. It renders microvessels hyperpermeable to plasma and stimulates endothelial cell migration and division. To investigate further the mechanisms by which RA inhibits angiogenesis, we evaluated the effects of RA on VPF/VEGF-induced angiogenesis and microvascular permeability. RA selectively inhibited the angiogenic response induced by VPF/VEGF, but not that induced by fibroblast growth factor-2 (FGF-2), in the CAM assay. RA and two of its isomers also inhibited the vascular permeabilizing effect of VPF/VEGF but not that induced by histamine. The vascular permeabilization induced by VPF/VEGF and blocked by RA takes place within 1-15 min, too short a time frame for RA to act by modulating transcription through classic retinoid receptors. RA also inhibited VPF/VEGF-induced phosphorylation of PLC-gamma and synthesis of cGMP but actually increased VPF/VEGF binding to cultured endothelial cells. Taken together, these findings indicate that RA selectively blocks VPF/VEGF-induced microvascular permeability and angiogenesis and also identify VPF/VEGF as a major target of RA action. The selectivity of RA's action suggests that other, RA-independent pathways must exist for the angiogenesis induced by FGF-2 and the vascular permeabilizing effect of histamine.

[Infusion chemotherapy and chemoembolization of liver metastases from cancer of the alimentary tract]

OBJECTIVE

To evaluate the efficacy of hepatic artery infusion chemotherapy and chemoembolization in the treatment of liver metastases from alimentary tract cancer.

METHODS

A total of 92 patients with unresectable liver metastases from alimentary tract cancer was treated 316 times by hepatic artery infusion chemotherapy and chemoembolization. Of the 92 patients, only infusion chemotherapy was performed in 29 patients, and infusion chemotherapy and chemoembolization in 63 patients. Chemotherapy was carried out with a combination of epirubicin and/or cisplatin, mitomycin-C, calcium folinate and 5-fluorouracil. Embolization was accomplished with lipiodol ultra-fluid or lipiodol ultra-fluid and gelatin sponge. Response rates were assessed by CT scanning.

RESULTS

An overall response rate (CR + PR) of the cases was 45.7%. The mean survival period of 92 patients was 19.6 months. The 0.5-, 1-, 2-, 3- and 5-year survival rate was 95.7%, 73.8%, 30.9%, 17.6% and 9.9%, respectively. Best therapeutic results were obtained in 9 cases with single metastatic focus in the liver, with a mean survival period of 31.2 months. There was no severe side effect or complication.

CONCLUSION

Treatment by transcatheter hepatic artery infusion chemotherapy and chemoembolization is beneficial to patients with metastatic cancer of the liver.

Tetracycline-inducible CaM kinase II silences hypertrophy-sensitive gene expression in rat neonate cardiomyocytes

Recent work from this laboratory both in rat primary cardiomyocytes and in ventricular tissue of transgenic mouse models of induced hypertrophy has identified two Ca(2+)/calmodulin-dependent nuclear signaling cascades. The first involves the phosphatase calcineurin (CaN). The second is the CaM kinase kinase cascade which involves CaM kinase I and CaM kinase IV. Each of these signaling cascades strongly up-regulate transcription of hypertrophy-sensitive genes in the rat ventricular cardiomyocyte. We have documented that over-expression of an active form of CaM kinase II silenced transcriptional induction of hypertrophy-sensitive genes. The purpose of this study was to generate an inducible CaM kinase II expression system and correlate its expression with the silencing of hypertrophic-sensitive reporters. A truncated form of CaM KII, CaM KII (1-290) was subcloned downstream and proximal to a promoter under transcriptional control (induction) of the tetracycline-regulated transcription factor, tet-TransActivator (tTA). Hypertrophy-sensitive reporter activity in primary cardiomyocytes was silenced when tet-inducible CaM KII was co-expressed with plasmids harboring active forms of CaN, CaM KI or CaM KIV. For instance, induced CaM KII expression silenced CaN, CaM kinase I, or CaM kinase IV driven ANF reporter activity 4.9-, 2.9-, and 6.9-fold below their maximal values, respectively. Myocyte exposure to doxycycline (DOX) blocked tTA-driven CaM KII expression and restored CaN/CaM KI or CaN/CaM KIV driven reporter activation. This study demonstrates, for the first time, that active CaM KII silences Ca(2+)-sensitive nuclear signaling cascades for transcriptional up-regulation of cardiomyocyte hypertrophy.

[Landscape structure of Longhua area in Shenzhen City during fast urbanization process--structure and heterogeneity analysis of urban construction area]

Remotely sensed mapping information of multi-period of time and methods of landscape pattern analysis were used to study the structure and spatial distribution characteristics of two types of land use, built-up areas and new developing areas, during the fast urbanization process in Longhua area, Shenzhen City. The results indicated that from 1988 to 1996, the patch number and average size in the two types of land use increased significantly, but the fragmentation degree decreased. The increase of constructed land use could be divided into two patterns, continued expanding of big residential patches and continuous appearing of new isolated small patches, and most of the new developing area was constructed from 1990 to 1994. Under the impacts of topography and traffic, the built-up areas showed macroscopic spatial distribution with decreasing lacunarity values. Distribution difference of constructed patches was very obvious in small and moderate scales. The new developing patches, affected by the conditions as the built-up areas, were also characteristic of macroscopic heterogeneity, but the expression scale of heterogeneity was larger than the built-up areas. The fast expanding of the constructed land use produced some very negative ecological problems, which should urgently be resolved by adjusting the land use polices.

Deuteron NMR investigation of a photomechanical effect in a smectic-A liquid crystal

Deuteron quadrupole-perturbed NMR is used to study the perturbation of orientational order in a smectic-A liquid crystal (octylcyanobiphenyl or 8CB) caused by photoinduced trans-to-cis isomerization of a photosensitive dopant (diheptylazobenzene or 7AB). The time and temperature dependences of the orientational order were independently studied for 8CB, 7AB, and their mixtures. Upon UV irradiation that causes trans-to-cis isomerization of 7AB, the orientational order parameter of the smectic-A phase is reduced. Relaxation in the dark exponentially restores the equilibrium value of the order parameter. The characteristic time for this process closely matches the lifetimes of the 7AB excited state. While in the 8CB smectic-A matrix, the cis-isomerized 7AB molecules retain a uniaxial orientational order with the director oriented along the normal to the smectic layers. The highly bent 7AB cis molecules act as a disorienting factor, decreasing the orientational order in the layers and causing a small increase in layer spacing. This disorder-induced increase in layer spacing is much smaller than the actual increase as observed by in situ x-ray experiments on UV-irradiated mixtures of 8CB:7AB. Concomitant with the experimental observation that only a fraction of 7AB molecules are converted to the cis state, this work provides indirect evidence for a nanophase segregation with the 7AB cis-isomers arranged within the interlayer space, thus significantly increasing the smectic layer spacing.

Sjögren's autoimmunity: how perturbation of recognition in endomembrane traffic may provoke pathological recognition at the cell surface

CD4 T cell antigen recognition requires presentation by major histocompatibility complex Class II molecules (MHC II). B cell surface immunoglobulins recognize antigens independently of MHC II, but activation typically requires CD4 cell cytokines as accessory signals. Plasma membrane-endomembrane traffic in lacrimal gland acinar cells, targets of autoimmune activity in Sjögren's syndrome, may satisfy both requirements. The Golgi protein galactosyltransferase and the lysosomal proteins cathepsin B and cathepsin D appear at the plasma membranes during sustained secretomotor stimulation. The RNA transcription termination factor La, a frequent target of Sjögren's autoantibodies, appears in the acinar cell cytoplasm and plasma membranes during viral infection and during in vitro exposure to cytokines. MHC II cycle through endomembrane compartments which contain La, galactosyltransferase, cathepsin B and cathepsin D and which are sites of proteolysis. This traffic may permit trilateral interactions in which B cells recognize autoantigens at the surface membranes, CD4 T cells recognize peptides presented by MHC II, B cells provide accessory signals to CD4 T cells, and CD4 T cells provide cytokines that activate B cells. Acinar cells stimulate lymphocyte proliferation in autologous mixed cell reactions, confirming that they are capable of provoking autoimmune responses.

[Response to milrinone treatment in patients with chronic congestive heart failure]

The objective of this study was to examine the efficacy of milrinone in chronic congestive heart failure. In this randomized, double-blind, placebo-controlled trial, 30 patients with class III or IV chronic congestive heart failure were randomly assigned to receive milrinone (n = 15) or placebo (n = 15). The results showed that in the milrinone group, stroke volume increased from 38.50 +/- 5.34 to 64.93 +/- 6.46 ml (P < 0.001), cardiac output increased from 3.39 +/- 0.42 to 5.28 +/- 0.55 L/min (P < 0.001), cardiac index increased from 2.01 +/- 0.42 to 3.21 +/- 0.57/min/m2 (P < 0.001) and ejection fraction increased from 0.23 +/- 0.05 to 0.35 +/- 0.06(P < 0.001). In the placebo group, no hemodynamic effects were found. Milrinone favourably influenced the symptoms and heart function in 11/15(73.3%) patients. In the placebo group, only 4/15(26.7%) patients had such response (P < 0.05). These data indicate that milrinone is effective for improving the hemodynamics status and heart function in patients with chronic heart failure.

CaM kinase signaling induces cardiac hypertrophy and activates the MEF2 transcription factor in vivo

Hypertrophic growth is an adaptive response of the heart to diverse pathological stimuli and is characterized by cardiomyocyte enlargement, sarcomere assembly, and activation of a fetal program of cardiac gene expression. A variety of Ca(2+)-dependent signal transduction pathways have been implicated in cardiac hypertrophy, but whether these pathways are independent or interdependent and whether there is specificity among them are unclear. Previously, we showed that activation of the Ca(2+)/calmodulin-dependent protein phosphatase calcineurin or its target transcription factor NFAT3 was sufficient to evoke myocardial hypertrophy in vivo. Here, we show that activated Ca(2+)/calmodulin-dependent protein kinases-I and -IV (CaMKI and CaMKIV) also induce hypertrophic responses in cardiomyocytes in vitro and that CaMKIV overexpressing mice develop cardiac hypertrophy with increased left ventricular end-diastolic diameter and decreased fractional shortening. Crossing this transgenic line with mice expressing a constitutively activated form of NFAT3 revealed synergy between these signaling pathways. We further show that CaMKIV activates the transcription factor MEF2 through a posttranslational mechanism in the hypertrophic heart in vivo. Activated calcineurin is a less efficient activator of MEF2-dependent transcription, suggesting that the calcineurin/NFAT and CaMK/MEF2 pathways act in parallel. These findings identify MEF2 as a downstream target for CaMK signaling in the hypertrophic heart and suggest that the CaMK and calcineurin pathways preferentially target different transcription factors to induce cardiac hypertrophy.

The study of surface transformation of pulsed laser deposited hydroxyapatite coatings

Hydroxyapatite (HA) coatings generally exhibit very good biocompatibility owing to their compositional resemblance to the natural hard tissue and to bioactive properties that are directly related to surface transformations in physiological fluids. In this study, two types of porous HA coatings produced with pulsed laser deposition were tested with respect to their dissolution/reprecipitation in a semidynamic simulated physiological solution. Coatings with higher porosity produced with a 355-nm wavelength laser exhibited significant reprecipitation earlier than those produced with a 266-nm wavelength laser. The dissolution of the non-HA phases played a major role in the reprecipitation of HA-like material as indicated by X-ray diffraction (XRD). The coatings' Ca/P ratio became closer to the theoretical value of HA. The newly formed HA had imperfect crystal structure and/or small crystal size as suggested by XRD. The reprecipitation resulted in a very dense morphology as shown by scanning electron microscopy, suggesting a mechanically strong structure after reprecipitation. Despite undergoing dissolution and reprecipitation, the coatings showed sufficient stability in the solution, as XRD and energy-dispersive X-ray studies indicated no significant loss of the coatings. The stability of these HA coatings and their ability to cause reprecipitation of HA in the simulated physiological solution showed the potential of these coatings for clinical applications.

Perk is essential for translational regulation and cell survival during the unfolded protein response

Malfolded proteins in the endoplasmic reticulum (ER) inhibit translation initiation. This response is believed to be mediated by increased phosphorylation of eukaryotic initiation factor 2alpha (eIF2alpha) and is hypothesized to reduce the work load imposed on the folding machinery during stress. Here we report that mutating the gene encoding the ER stress-activated eIF2alpha kinase PERK abolishes the phosphorylation of eIF2alpha in response to accumulation of malfolded proteins in the ER resulting in abnormally elevated protein synthesis and higher levels of ER stress. Mutant cells are markedly impaired in their ability to survive ER stress and inhibition of protein synthesis by cycloheximide treatment during ER stress ameliorates this impairment. PERK thus plays a major role in the ability of cells to adapt to ER stress.