Muscular Asthenopia and Eccentric Ablation After Photorefractive Keratectomy

PURPOSE

To investigate the relationship between muscular asthenopia and eccentric ablation after photorefractive keratectomy (PRK).

METHODS

Sixteen eyes of eight myopic patients whose muscular asthenopia was corrected by subjectively accepted spectacle prism after PRK, with visual acuity better than 0.8, were followed for 6 to 14 months. On the basis of preoperative and post-operative data and corneal topography, we calculated the total corrected corneal power using the Holladay formula and then measured the ablation eccentricity (h, millimeters) and its direction. According to the formula delta approximately equals Dh, the prism effective value (delta) caused by the eccentric ablation was computed and compared with the objectively accepted spectacle prism.

RESULTS

The subjectively accepted spectacle prisms were similar to calculated values from the formula. Mean difference was 0.10 +/- 0.25delta. The direction of the subjectively accepted prism was in the direction of the ablation deviation.

CONCLUSIONS

Eccentric ablation is an important cause of muscular visual asthenopia after PRK. The asthenopia may be corrected by spectacle prism. The spectacle prism value may be estimated by the formula delta approximately equals Dh.

Enhanced sensitivity in RIACT/MQ-MAS NMR experiments using rotor assisted population transfer

The rotor assisted population transfer (RAPT) sequence is used to enhance the sensitivity of the RIACT(II) experiment for spin-3/2 quadrupolar nuclei. A detailed theoretical analysis of the polarizations that contribute to different types of MQ-MAS experiments is provided. In particular, two polarization pathways are distinguished for the creation of triple-quantum coherence. The existence of these pathways is experimentally demonstrated by comparing the sensitivities of different sequences with and without RAPT preparation.

Identification of putative downstream genes of Oct-4 by suppression-subtractive hybridization

As a step toward understanding how toti/pluripotence is maintained by Oct-4, we have first constructed a cell model with differentially expressed Oct-4 in embryonic stem cells, and then used suppression-subtractive hybridization (SSH) method to identify the downstream genes of Oct-4. Among the 384 clones we screened, 40 clones were detected as differentially expressed genes with colony hybridization, and 13 clones were confirmed as the putative downstream genes of Oct-4 by Northern blot analysis. Sequencing showed 12 different genes, 8 known genes (Oct-4, Rex-1, Sox-2, Creatine kinase B, Makorin 1, Importin beta, Histone H2A.Z, Ribosomal protein S7) and 4 new genes. Except Oct-4 and Rex-1, the other genes have not been reported to be regulated by Oct-4. These results showed that SSH provides a very efficient means to identify the downstream genes of transcription factor. Some known genes identified may provide new insight of the function of Oct-4 in stem cells.

The impact of chronic estrogen deprivation on immunologic parameters in the ovariectomized rhesus monkey (Macaca mulatta) model of menopause

A large clinical literature suggests that estradiol (E(2)) plays a critical role in immune function. To further explore the relationship between E(2) and immune function, we examined a variety of immunological parameters in a rhesus monkey model of menopause and hormone replacement therapy. Rhesus monkeys (Age, 13.7+/-2.6 years) were ovariectomized and received either sham (n=10) or estradiol (n=10) replacement implants. Nine months post-ovariectomy, a variety of immunologic parameters were measured. E(2)-deprivation reduced natural killer cell activity and increased serum soluble gp130 levels. There was a trend for an increased proportion of CD8(+) (P=0.12) and HLA-DR(+)CD3(+) cells (P=0.15) and decreased proportion of eosinophils (P=0.11) in the E(2)-deprived monkeys. There was no difference in leukocyte distribution, CD28, CD56, CD4, CD8/CD45, colony forming units-granulocyte/monocytes formation, peripheral blood mononuclear cell apoptotic rate, or serum TNF, TNF-R1, TNF-R2, IL-6, soluble IL-6R, and IL-1 between the groups. These data demonstrate that E(2)-deprivation affects several aspects of immune function. These findings may have implications for menopause-associated changes of immune function that occur in women.

Signal transduction of flumazenil-induced preconditioning in myocytes

The objective of this study was to examine the role of oxygen radicals, protein kinase C (PKC), and ATP-sensitive K(+) (K(ATP)) channels in mediating flumazenil-produced preconditioning. Chick cardiomyocyte death was quantified using propidium iodide, and oxygen radical generation was assessed using 2',7'-dichlorofluorescin oxidation. Preconditioning was initiated with 10 min of ischemia followed by 10 min of reoxygenation. Alternatively, flumazenil was infused for 10 min and removed 10 min before ischemia. Flumazenil (10 microM) and preconditioning increased oxygen radicals [1,693 +/- 101 (n = 3) and 1,567 +/- 98 (n = 3), respectively, vs. 345 +/- 53 (n = 3) in control] and reduced cell death similarly [22 +/- 3% (n = 5) and 18 +/- 2% (n = 6), respectively, vs. controls 49 +/- 5% (n = 8)]. Protection and increased oxygen radicals by flumazenil were abolished by pretreatment with the antioxidant thiol reductant 2-mercaptopropionyl glycine (800 microM; 52 +/- 10%, n = 6). Specific PKC inhibitors Go-6976 (0.1 microM) and chelerythrine (2 microM), given during ischemia and reoxygenation, blocked flumazenil-produced protection (47 +/- 5%, n = 6). The PKC activator phorbol 12-myristate 13-acetate (0.2 microM), given during ischemia and reoxygenation, reduced cell death similarly to that with flumazenil [17 +/- 4% (n = 6) and 22 +/- 3% (n = 5)]. Finally, 5-hydroxydecanoate (1 mM), a selective mitochondrial K(ATP) channel antagonist given during ischemia and reoxygenation, abolished the protection of flumazenil and phorbol 12-myristate 13-acetate. Thus flumazenil mimics preconditioning to reduce cell death in cardiomyocytes. Oxygen radicals activate mitochondrial K(ATP) channels via PKC during the process.

Human casein kinase Idelta phosphorylation of human circadian clock proteins period 1 and 2

Casein kinase Iepsilon (CKIepsilon), a central component of the circadian clock, interacts with and phosphorylates human period protein 1 (hPER1) [Keesler, G.A. et al. (2000) NeuroReport 5, 951-955]. A mutation in CKIepsilon causes a shortened circadian period in Syrian Golden hamster. We have now extended our previous studies to show that human casein kinase Idelta (hCKIdelta), the closest homologue to hCKIepsilon, associates with and phosphorylates hPER1 and causes protein instability. Furthermore, we observed that both hCKIdelta and hCKIepsilon phosphorylated and caused protein instability of human period 2 protein (hPER2). Immunohistochemical staining of rat brains demonstrates that CKIdelta protein is localized in the suprachiasmatic nuclei, the central location of the master clock. These results indicate that CKIdelta may play a role similar to CKIepsilon, suggesting that it may also be involved in regulating circadian rhythmicity by post-translation modification of mammalian clock proteins hPER1 and 2.

Post-PRK muscular asthenopia and eccentric ablation

OBJECTIVE

To investigate the relationship between muscular asthenopia post photorefractive keratectomy (PRK) and eccentric ablation.

METHODS

16 eyes of 8 myopia cases whose muscular asthenopia was corrected by subjectively accepted triangular prism after PRK with vision more than 0.8 were followed up for 6-14 months. On the basis of data provided by the pre-PRK, post-PRK and their difference corneal topography, we calculated the real corrected corneal diopter (D) with the Holladay formula and measured the ablating eccentricity (h) and its direction. According to the formula delta approximately Dh, the prism effective value (delta) caused by the eccentric ablation was computed and compared with objectively accepted triangular prism.

RESULTS

The subjectively accepted prism was similar to values calculated from the formula. Their mean difference is 0.10 +/- 0.25. The direction of the subjectively accepted prism was in the direction of ablation deviation.

CONCLUSIONS

Eccentric ablation was the chief cause of post-PRK muscular visual asthenopia. The triangular prism effective value from eccentric ablation may be estimated by the formula delta approximately Dh. We must pay attention to the diagnosis, treatment and prevention of post-PRK muscular asthenopia.

Ethanol activates NFkappaB DNA binding and p56lck protein tyrosine kinase in human osteoblast-like cells

Alcoholics frequently suffer from moderate to severe bone loss that results in bone fractures. Both decreased bone production and increased bone resorption have been postulated to contribute to ethanol (ETOH)-mediated bone loss. Bone resorption is induced by several proinflammatory cytokines such as interleukin-1 and -6. The expression of these cytokines is induced by the transcription factor NFkappaB, which, in turn, is activated by several kinases. It follows that protein kinase and NFkappaB activation may contribute to ETOH-induced bone loss. Accordingly, we sought to determine if ETOH activates protein tyrosine kinases (PTK) and NFkappaB DNA binding in a human osteoblast-like cell line (HOBIT). Ethanol at 50 and 100 mmol/L (reflective of blood ethanol levels reached in chronic alcoholics) for 24 h did not alter HOBIT cell viability. In contrast, 200 mmol/L ethanol decreased cell viability by 40%. Treatment of HOBIT cells with 100 mmol/L ETOH induced nuclear NFkappaB:DNA complex formation and NFkappaB activity. Incubation of HOBIT cells with ETOH at 50 and 100 mmol/L for 30 min induced a 2.5- and 4.2-fold increase in PTK activity, respectively. Preincubation of HOBIT cells with damnacanthal (DAM), which inhibits p56lck, blocked ETOH-mediated PTK activity; whereas, preincubation with herbimycin A, which inhibits pp60src, did not. DAM inhibited both ethanol-induced NFkappaB activation in HOBIT cells and interleukin-6 expression in primary human osteoblasts. Finally, preincubation with the protein kinase C inhibitor, bisindolylmaleimide I HCl (BIS), diminished ETOH-mediated PTK activity; whereas, preincubation with the protein kinase A inhibitor, H89, did not. These data demonstrate that ETOH induces NFkappaB nuclear translocation through p56lck in HOBIT cells. BIS' inhibition of PTK activation suggests that ETOH activates PTK through a protein kinase C-dependent pathway. These data suggest that ETOH may contribute to bone loss through activation of signal transduction that results in production of an osteoclastogenic cytokine (i.e., interleukin-6) in osteoblasts.

Cholesterol binding at the cholesterol recognition/ interaction amino acid consensus (CRAC) of the peripheral-type benzodiazepine receptor and inhibition of steroidogenesis by an HIV TAT-CRAC peptide

We previously defined a cholesterol recognition/interaction amino acid consensus (CRAC; ATVLNYYVWRDNS) in the carboxyl terminus of the peripheral-type benzodiazepine receptor (PBR), an outer mitochondrial membrane protein involved in the regulation of cholesterol transport into the mitochondria, the rate-determining step in steroid biosynthesis. We examined (i) the PBR-cholesterol interaction by UV crosslinking of the C17 side-chain containing progestin, promegestone, and (ii) the role of the CRAC domain of PBR in Leydig cell steroidogenesis by using a transducible peptide composed of the TAT domain of HIV and the CRAC domain of PBR. [(3)H]Promegestone photoincorporated into recombinant PBR, and this labeling was displaced by cholesterol. [(3)H]Promegestone also photoincorporated into the TAT-CRAC peptide. [(3)H]Promegestone crosslinking to TAT-CRAC could be displaced by cholesterol and promegestone, with IC50 values of 1 and 200 microM, respectively. TAT-CRAC efficiently transduced into MA-10 Leydig cells and inhibited the hCG- and cAMP-stimulated steroid production in a dose-dependent manner. TAT-CRAC did not affect the hCG-induced cAMP synthesis and the 22R-hydroxycholesterol-supported steroidogenesis. Mutated TAT-CRAC lost its ability to bind [(3)H]promegestone and to inhibit the hCG-stimulated steroidogenesis. These results show that TAT-CRAC binds cholesterol and competes for cholesterol interaction with endogenous PBR, suggesting that the cytosolic carboxyl-terminal domain of PBR is responsible for taking up and bringing steroidogenic cholesterol into the mitochondria.

The insulin-stimulated cell surface presentation of low density lipoprotein receptor-related protein in 3T3-L1 adipocytes is sensitive to phosphatidylinositide 3-kinase inhibition

The regulation of low density lipoprotein receptor-related protein (LRP) activity by insulin was studied using 3T3-L1 adipocytes. The LRP mRNA and protein expression were independent of differentiation state of the cells and of insulin treatment. In differentiated cells, insulin treatment acutely stimulated the cell surface presentation of LRP (approximately 2-fold) as evidenced by methylamine-activated alpha(2)-macroglobulin binding and by biotinylation of cell surface LRP. The increased cell surface presentation was accompanied by a 39% decrease in LRP level in the low density microsomes. The magnitude of insulin-stimulated cell surface presentation of LRP was similar to that of transferrin receptor but was much less than that of GLUT4. Both the increases in LRP and GLUT4 cell surface presentation upon insulin treatment were abolished by inhibition of phosphatidylinositide 3-kinase. The increased cell surface presentation of LRP was associated with proportionally increased endocytic activity, and the internalization rate constant (K(e)) was not decreased by insulin treatment. Thus, insulin treatment most likely stimulates recycling of LRP from an endosomal pool to the plasma membrane, which is regulated in a phosphatidylinositide 3-kinase-dependent manner in 3T3-L1 adipocytes.

The Ginkgo biloba extract EGb 761 rescues the PC12 neuronal cells from beta-amyloid-induced cell death by inhibiting the formation of beta-amyloid-derived diffusible neurotoxic ligands

beta Amyloid (Abeta) treatment induced free radical production and increased glucose uptake, apoptosis and cell death in PC12 nerve cells. Addition of the standardized extract of Ginkgo biloba leaves, EGb 761 together with the Abeta protein prevented, in a dose-dependent manner, the Abeta-induced free radical production, increased glucose uptake, apoptosis and cell death. However, pretreatment of the cells with EGb 761 did not rescue the cells from the Abeta-induced toxicity although it prevented the Abeta-induced reactive oxygen species generation. Moreover, the terpene and flavonoid-free EGb 761 extract, HE 208, although inhibited the Abeta-induced increased glucose uptake, it failed to protect the cells from apoptosis and cytotoxicity induced by Abeta. In conclusion, these results indicate that the terpenoid and flavonoid constituents of EGb 761, acting probably in combination with components present in HE 208, are responsible for rescuing the neuronal cells from Abeta-induced apoptosis and cell death; their mechanism of action being distinct of their antioxidant properties. Because pre- and post-treatment with EGb 761 did not protect the cells from Abeta-induced neurotoxicity, we examined whether EGb 761 interacts directly with Abeta. Indeed, in vitro reconstitution studies demonstrated that EGb 761 inhibits, in a dose-dependent manner, the formation of beta-amyloid-derived diffusible neurotoxic soluble ligands (ADDLs), suggested to be involved in the pathogenesis of Alzheimer's disease.

Morphine mimics preconditioning via free radical signals and mitochondrial K(ATP) channels in myocytes

BACKGROUND

We tried to determine whether morphine mimics preconditioning (PC) to reduce cell death in cultured cardiomyocytes and whether opioid delta(1) receptors, free radicals, and K(ATP) channels mediate this effect.

METHODS AND RESULTS

Chick embryonic ventricular myocytes were studied in a flow-through chamber while flow rate, pH, and O(2) and CO(2) tension were controlled. Cardiomyocyte viability was quantified with propidium iodide (5 micromol/L), and production of free radicals was measured with 2',7'-dichlorofluorescin diacetate. PC with 10 minutes of simulated ischemia before 10 minutes of reoxygenation or morphine (1 micromol/L) or BW373U86 (10 pmol/L) infusion for 10 minutes followed by a 10-minute drug-free period before 1 hour of ischemia and 3 hours of reoxygenation reduced cell death to the same extent (*P:<0.05) (PC, 20+/-1%, n=7*; morphine, 32+/-4%, n=8*; BW373U86, 21+/-6%; controls, 52+/-5%, n=8). Like PC, morphine and BW373U86 increased free radical production 2-fold before ischemia (0.35+/-0.10, n=6*; 0.41+/-0.08, n=4* versus controls, 0.15+/-0.05, n=8, arbitrary units). Protection and increased free radical signals during morphine infusion were abolished with either the thiol reductant 2-mercaptopropionyl glycine (400 micromol/L), an antioxidant; naloxone (10 micromol/L), a nonselective morphine receptor antagonist; BNTX (0.1 micromol/L), a selective opioid delta(1) receptor antagonist; or 5-hydroxydecanoate (100 micromol/L), a selective mitochondrial K(ATP) channel antagonist.

CONCLUSIONS

These results suggest that direct stimulation of cardiocyte opioid delta(1) receptors leads to activation of mitochondrial K(ATP) channels. The resultant increase of intracellular free radical signals may be an important component of the signaling pathways by which morphine mimics preconditioning in cardiomyocytes.

Bone morphogenetic protein-15. Identification of target cells and biological functions

In developing ovarian follicles, the regulation of cell proliferation and differentiation is tightly coordinated. Precisely how this coordination is achieved is unknown, but recent observations have suggested that molecules emitted by the oocyte are involved in the process. The newly discovered oocyte-specific growth factor, bone morphogenetic protein-15 (BMP-15), is one such molecule. At present, nothing is known about the target cells and biological functions of BMP-15. To fill this gap in our knowledge, recombinant BMP-15 and its antibody were produced and used to determine BMP-15 expression and bioactivity. BMP-15 mRNA and protein were shown to be co-expressed in oocytes throughout folliculogenesis, supporting the idea that BMP-15 is a physiological regulator of follicle cell proliferation and/or differentiation. To test this, we used primary cultures of rat granulosa cells (GCs). We found that BMP-15 is a potent stimulator of GC proliferation, and importantly, the mitogenic effect was follicle-stimulating hormone (FSH)-independent. By contrast, BMP-15 alone had no effect on steroidogenesis. However, it produced a marked decrease in FSH-induced progesterone production, but had no effect on FSH-stimulated estradiol production. This result indicates that BMP-15 is a selective modulator of FSH action. In summary, this study identifies GCs as the first target cells for BMP-15. Moreover, it identifies the stimulation of GC proliferation and the differential regulation of two crucial steroid hormones as the first biological functions of BMP-15. Significantly, BMP-15 is the first growth factor that can coordinate GC proliferation and differentiation in a way that reflects normal physiology.

[Etiological study on patients with seronegative viral hepatitis]

OBJECTIVE

To investigate the etiology of hepatitis patients who were seronegative for viral hepatitis A through E.

METHODS

By using PCR, HBV DNA, HCV RNA, HEV RNA and HGV RNA were detected in sera of 104 patients with seronegative viral hepatitis. The partial nucleotide sequences of 2 HCV and 17 HEV isolates were analysed by direct sequencing.

RESULTS

Among the 104 patients with seronegative viral hepatitis, the positive rates of HBV DNA, HCV RNA, HEV RNA and HGV RNA were 29.8%, 3.8%, 22.1% and 7.7%, respectively, with only 38 cases (36.6%) negative for the genome of all known hepatitis viruses.

CONCLUSION

In addition to serological tests, the polymerase chain reaction of all known hepatitis viruses should be used to make the diagnosis of non-A - E hepatitis.

Interpenetrating polymer networks of alginate and polyethylene glycol for encapsulation of islets of Langerhans

A mixture of alginate and polyethylene glycol acrylate was investigated as a system for the encapsulation of islets of Langerhans. This system showed dual crosslinkability: the alginate was ionically crosslinked by multivalent cations, and the PEG was covalently crosslinked by photoactivated free radical polymerization. The major advantage of the dually crosslinkable system was the chemical stability of the resultant gels due to the presence of covalent bonds that maintain the integrity of the gel as opposed to reversible ionic linkages that were the only mode of crosslinkage in previous generations of alginate-based encapsulation systems. The physical aspects of gelation of such alginate/PEG compositions were investigated. Diffusion of dextrans of known molecular weights through these gels was studied in order to shed light on the hydrogel porosity and permeability. In vitro viability and function tests demonstrated that these gels were biocompatible. Islets encapsulated in these systems were healthy and retained both viability and insulin secretory function.

[The spectra and thermodynamics of axial coordination reaction of tailed valine tetraphenylporphintozinc with pyrimidine]

The electronic absorption spectra and thermodynamics of axial coordination reaction of 5-(4-valine butoxyphenyl)-10,15,20-tri(4-chlorophenyl)porphintozinc with pyrimidine in CHCl3 were studied. Coordination numbers and equilibrium constants of axial coordination reaction were measured by visible spectra techniques. The changes of standard molar enthalpies and standard molar entropies of reaction were obtained from the plots of ln beta vs 1/T. The influence of temperature on the axial reaction was discussed.

Flumazenil preconditions cardiomyocytes via oxygen radicals and K(ATP) channels

We determined whether flumazenil mimics ischemic preconditioning in chick cardiomyocytes and examined the role of intracellular reactive oxygen species (ROS) and ATP-dependent potassium (K(ATP)) channels in mediating the effect. Chick ventricular myocytes were perfused with a balanced salt solution in a flow-through chamber. Cell viability was quantified using propidium iodide, and ROS generation was assessed using the reduced form of 2',7'-dichlorofluorescin (DCFH). Cells were exposed to 1 h of simulated ischemia and 3 h of reoxygenation. Preconditioning was initiated with 10 min of ischemia followed by 10 min of reoxygenation. Alternatively, flumazenil was added to the perfusate for 10 min and removed 10 min before the start of ischemia. Flumazenil (1 and 10 microM) and preconditioning reduced cell death [54 +/- 5%, n = 3; 26 +/- 4%, n = 6 (P < 0.05); and 20 +/- 2%, n = 6 (P < 0.05), respectively, vs. 57 +/- 7%, n = 10, in controls] and increased DCFH oxidation (an index of ROS production) [0.35 +/- 0.11, n = 3; 2.64 +/- 0.69, n = 8 (P < 0.05); and 2.46 +/- 0.52, n = 6 (P < 0.05), respectively, vs. 0.26 +/- 0.05, n = 9, in controls]. Protection and increased ROS signals with flumazenil (10 microM) were abolished with the thiol reductant N-(2-mercaptopropionyl)-glycine (2-MPG, 800 microM), an antioxidant (cell death: 2-MPG + flumazenil, 55 +/- 12%, n = 6; ROS signals: 2-MPG + flumazenil, 0.11 +/- 0.19, n = 6). Treatment with 5-hydroxydecanoate (1 mM), a selective mitochondrial K(ATP) channel antagonist, abolished its protection. These results demonstrate that flumazenil mimics preconditioning to reduce cell death in myocytes. ROS signals with the resultant mitochondrial K(ATP) channel activation are important components of the intracellular signaling pathway of flumazenil.

Chronic alcohol ingestion induces osteoclastogenesis and bone loss through IL-6 in mice

To investigate the role of IL-6 in alcohol-mediated osteoporosis, we measured a variety of bone remodeling parameters in wild-type (il6(+/+)) or IL-6 gene knockout (il6(-/-)) mice that were fed either control or ethanol liquid diets for 4 months. In the il6(+/+) mice, ethanol ingestion decreased bone mineral density, as determined by dual-energy densitometry; decreased cancellous bone volume and trabecular width and increased trabecular spacing and osteoclast surface, as determined by histomorphometry of the femur; increased urinary deoxypyridinolines, as determined by ELISA; and increased CFU-GM formation and osteoclastogenesis as determined ex vivo in bone marrow cell cultures. In contrast, ethanol ingestion did not alter any of these parameters in the il6(-/-) mice. Ethanol increased receptor activator of NF-kappaB ligand (RANKL) mRNA expression in the bone marrow of il6(+/+) but not il6(-/-) mice. Additionally, ethanol decreased several osteoblastic parameters including osteoblast perimeter and osteoblast culture calcium retention in both il6(+/+) and il6(-/-) mice. These findings demonstrate that ethanol induces bone loss through IL-6. Furthermore, they suggest that IL-6 achieves this effect by inducing RANKL and promoting CFU-GM formation and osteoclastogenesis.

Dynamic changes of serum vascular endothelial growth factor levels in a rat myocardial infarction model

OBJECTIVE

To investigate the dynamic changes of serum vascular endothelial growth factor (VEGF) levels in a rat model of acute myocardial infarction.

MATERIALS AND METHODS

Eighty-eight adult male Sprague-Dawley rats weighing approximately 270 g we used in this study. Eighty rats were subjected to left coronary artery ligation, with 8 rats for each different duration of infarct. Eight sham-operated animals in which the left coronary artery was surgically exposed without ligation were used as controls. Blood samples were drawn from the right atrium before (sham animals) and 1, 3, 6, 12, 24 h and 2, 3, 5, 7, 14 d after myocardial infarction. The concentrations of serum VEGF were measured by a sensitive enzyme-linked imosorbent assay with a rabbit polyclonal antibody specific for VEGF.

RESULTS

In the 8 control animals, the mean concentration of serum VEGF was 66.99 +/- 17.83 pg/ml. Six hours after myocardial infarction, the level of serum VEGF significantly increased to 125.68 +/- 28.07 pg/ml (P < 0.01 vs x sham controls), and reached a peak (240.61 +/- 70.63 pg/ml. P < 0.01 vs x sham animals) at 24 h after ligation and then decreased gradually over the remaining 2 weeks. However, the level remained significantly elevated for 14 d (107.64 +/- 30.13 pg/ml, P < 0.01 vs x sham controls).

CONCLUSION

The present study shows that the levels of serum VEGF are markedly increased until 14 d in the rat model of acute myocardial infarction. The increased serum VEGF level may play an important role in the angiogenesis associated with myocardial infarction.

The assembly of very low density lipoproteins in rat hepatoma McA-RH7777 cells is inhibited by phospholipase A2 antagonists

In McA-RH7777 cells, the oleate-stimulated assembly and secretion of very low density lipoproteins (VLDL) was associated with enhanced deacylation of phospholipids, which was markedly decreased by inactivation of the cellular phospholipase A(2). Treatment of the cells with antagonists or antisense oligonucleotide of the Ca(2+)-independent phospholipase A(2) (iPLA(2)) significantly inhibited secretion of apoB100-VLDL and triglyceride. Similar inhibitory effect of the iPLA(2) antagonists was observed on apoB48-VLDL secretion, but secretion of high density lipoprotein particles (such as apoAI- and apoB48-high density lipoprotein) or proteins in general was unaffected. The iPLA(2) antagonist did not affect the synthesis of apoB100 or triglyceride, nor did it affect the activities of phospholipase D, phosphatidate phosphohydrolase, or microsomal triglyceride transfer protein. Inactivation of iPLA(2) resulted in impaired apoB100-VLDL assembly as shown by decreased apoB100-VLDL and triglyceride within the microsomal lumen, with concomitant increase in apoB100 association with the microsomal membranes. The inhibitory effect of iPLA(2) antagonists on apoB100-VLDL assembly/secretion could be abated by pretreatment of cells with oleate. Analysis of molecular species of microsomal phosphatidylcholine and phosphatidylethanolamine by electron spray tandem mass spectrometry revealed that the enrichment of oleoyl moieties was altered by the treatment of iPLA(2) antagonist. These results suggest that the oleate-induced VLDL assembly/secretion may depend upon the establishment of membrane glycerolipids enriched in oleoyl chain, a process mediated by the iPLA(2) activity.

[The study of induced circular dichroism of phenylalanine bridged metal bis-porphyrin]

L- and D-phenylalanine bridged zinc bis-porphyrin with the connecting chain at ortho and para position of two phenyl rings [o,o-C2-Phe-C2-(TPP)2Zn2 and p,p-C2-Phe-C2-(TPP)2Zn2] have been synthesized and characterized. o,o-C2-Phe-C2-(TPP)2Zn2 exhibited strong induced circular dichroism (ICD). While p,p-C2-Phe-C2-(TPP)2Zn2 exhibited no significant ICD. The ICD of present complexes were mainly determined by the pi-pi interaction and chiral excition coupling between two porphyrin moieties of the molecules. Our results also indicated that the existence of chiral center in a porphyrin molecule does not mean it would surely exhibit ICD.

Microbial production of spider silk proteins

The remarkable properties of spider dragline silk and related protein polymers will find many applications if the materials can be produced economically. We have demonstrated the production of high molecular weight spider dragline silk analog proteins encoded by synthetic genes in several microbial systems, including Escherichia coli and Pichia pastoris. In E. coli, proteins of up to 1000 amino acids in length could be produced efficiently, but the yield and homogeneity of higher molecular weight silk proteins were found to be limited by truncated synthesis, probably as a result of ribosome termination errors. No such phenomenon was observed in the yeast P. pastoris, where higher molecular weight silk proteins could be produced without heterogeneity due to truncated synthesis. Spider dragline silk analog proteins could be secreted by P. pastoris when fused to both the signal sequence and N-terminal pro-sequence of the Saccharomyces cerevisiae alpha-mating factor gene.

Leaf morphology and cuticular features of Sphenophyllum in the Gigantopteris flora from South China

Permian specimens of Sphenophyllum with preserved cuticular anatomy have been discovered in Cathaysia and have prompted a detailed re-evaluation of the genus in the Gigantopteris flora in South China. New specimens are described and previously published material is re-examined to clarify taxonomic diversity and to establish geographic and stratigraphic ranges for each species. Recognized taxa include Sphenophyllum apiciserratum sp. nov., S. koboense Kobatake, S. meridionale sp. nov., S. minor (Sterzel) Gu and Zhi, S. sinocoreanum Yabe, S. cf. sinocoreanum Yabe, and S. aff. speciosum (Royle) McClelland. Cuticles of Sphenophyllum apiciserratum and S. koboense are hypostomatic with randomly disposed ordinary cells in intercostal regions. Specific concepts are clarified and unresolved taxonomic problems are discussed. The South China taxa are compared with those from Euramerican, Gondwanan and Angaran floras, and the South China Cathaysian species are found to be taxonomically distinct.