Bending of the distraction site during mandibular distraction osteogenesis in the rabbit: a model for studying segment control and side effects

PURPOSE

The purpose of this investigation was to develop an animal model for studying and correcting mandibular distraction side effects.

MATERIALS AND METHODS

Twenty-nine rabbits underwent bilateral mandibular distraction. Bending of the mandible was accomplished by offsetting a linear distraction by 35 degrees from the occlusal plane (4 screws per distractor), rotating the anterior segment inferiorly (2 screws per distractor), and removing a 3- or 6-mm wedge of the distraction site. The amount of bite opening varied according to the surgical design. Direct measurements, radiographs, and histology samples were compared.

RESULTS

Linear distraction produced a 4-mm anterior open bite and a Class III malocclusion after 2 weeks of distraction. Segmental rotation produced an 8-mm anterior open bite without complications. Removal of a wedge initiated rotation of the anterior segment. A large wedge (6 mm) produced fibrous union in the distraction site. The amount of bite opening or closure depended on the number of surgical screws and position of the distractor. Serial histologic sections showed bone formation at the rotated, triangular distraction site.

CONCLUSION

Bite opening or closure can occur from loss of segment control or by altering surgical design. This information is needed to counter unwanted side effects or to plan segment rotations.

Cooperative regulation of Mcl-1 by Janus kinase/stat and phosphatidylinositol 3-kinase contribute to granulocyte-macrophage colony-stimulating factor-delayed apoptosis in human neutrophils

Polymorphonuclear neutrophils (PMN) are phagocytic cells constitutively programmed for apoptotic cell death. Exposure to GM-CSF delays apoptosis as measured by annexin-V staining and cell morphological change. We found that STAT5B, STAT1, and STAT3 DNA-binding activity was induced by GM-CSF. We also detected activation of the phosphatidylinositol 3-kinase (PI 3-kinase) pathway after GM-CSF treatment which was inhibited by treatment with the PI 3-kinase inhibitors, wortmannin and LY294002. We investigated whether STAT or PI 3-kinase activity was necessary for the pro-survival response of GM-CSF in PMN. Exposure of PMN to GM-CSF in the presence of either AG-490, antisense STAT3 oligonucleotides, or wortmannin resulted in a partial inhibition of GM-CSF-mediated pro-survival activity. GM-CSF induced a time-dependent increase in the mRNA and protein expression of the anti-apoptotic Bcl-2-family protein, Mcl-1. We examined the hypothesis that Janus kinase/STAT and PI 3-kinase regulation of Mcl-1 contributed to GM-CSF-delayed apoptosis. Using either AG-490 or wortmannin alone, we observed a dose-dependent inhibition of GM-CSF-induced Mcl-1 expression. Using suboptimal doses of AG-490 and wortmannin, we found that both drugs together had an additive effect on delayed apoptosis and Mcl-1 expression. These data suggest that cooperative regulation of Mcl-1 by the Janus kinase/STAT and PI 3-kinase pathways contribute to GM-CSF-delayed apoptosis.

Immune-type receptor genes in zebrafish share genetic and functional properties with genes encoded by the mammalian leukocyte receptor cluster

An extensive, highly diversified multigene family of novel immune-type receptor (nitr) genes has been defined in Danio rerio (zebrafish). The genes are predicted to encode type I transmembrane glycoproteins consisting of extracellular variable (V) and V-like C2 (V/C2) domains, a transmembrane region and a cytoplasmic tail. All of the genes examined encode immunoreceptor tyrosine-based inhibition motifs in the cytoplasmic tail. Radiation hybrid panel mapping and analysis of a deletion mutant line (b240) indicate that a minimum of approximately 40 nitr genes are contiguous in the genome and span approximately 0.6 Mb near the top of zebrafish linkage group 7. One flanking region of the nitr gene complex shares conserved synteny with a region of mouse chromosome 7, which shares conserved synteny with human 19q13.3-q13.4 that encodes the leukocyte receptor cluster. Antibody-induced crosslinking of Nitrs that have been introduced into a human natural killer cell line inhibits the phosphorylation of mitogen-activated protein kinase that is triggered by natural killer-sensitive tumor target cells. Nitrs likely represent intermediates in the evolution of the leukocyte receptor cluster.

[The effects of leptin on proliferation and function of human osteoblast]

OBJECTIVE

To observe the effect of leptin on osteoblast.

METHODS

Human osteoblast primary culture was carried out, and the morphology and function of osteoblast were observed. The effects of different levels of leptin on osteoblast in different days were assessed by MTT colorimetry. Osteocalcin production was measured also.

RESULTS

Human osteoblasts were fusiform in shape and were positive for alkaline phosphatase by histochemical staining, positive for osteocalcin by immunofluorescence staining, and positive by Alizarin Reds staining after mineralized upon supplementation with ascorbate and beta-glycerophosphate. On the first, second and third days, the proliferation of osteoblast, cultured with different concentrations of leptin, had no changes. The leptin-stimulated synthesis of osteocalcin of cells was found to be dose-dependent (P < 0.05), but not time-dependent (P > 0.05).

CONCLUSION

The above data indicated that there were no evidences for the effects of leptin on the proliferation of human osteoblast, but leptin could enhance the function of human osteoblast.

Epoxygenase metabolites contribute to nitric oxide-independent afferent arteriolar vasodilation in response to bradykinin

In the kidney, epoxyeicosatrienoic acids (EETs) have been suggested to be endothelium-derived hyperpolarizing factors (EDHFs). The aim of the present study was to determine the contribution of EETs to the preglomerular vasodilation elicited by bradykinin. Sprague-Dawley rats were studied utilizing an in vitro perfused juxtamedullary nephron preparation. The afferent arteriolar diameter was determined and the diameter averaged 19 +/- 1 microm (n = 26) at a renal perfusion pressure of 100 mm Hg. Addition of 1, 10 and 100 nM bradykinin to the perfusate dose-dependently increased afferent arteriolar diameter by 5 +/- 1, 12 +/- 2 and 17 +/- 2%, respectively. The nitric oxide inhibitor N(omega)-nitro-L-arginine reduced bradykinin-induced afferent arteriolar vasodilation by 50%, and the diameter increased by 9 +/- 2% in response to 100 nM bradykinin. Epoxygenase inhibitors N-methylsulphonyl-6-(2-propargyloxyphenyl)hexanamide or miconazole greatly attenuated the nitric oxide-independent component of the vasodilation elicited by bradykinin. Cyclooxygenase (COX) inhibition attenuated the nitric oxide-independent vasodilation elicited by 1 nM bradykinin but did not significantly affect the vascular response to 100 nM bradykinin. Combined inhibition of nitric oxide, COX and epoxygenase pathways completely abolished bradykinin-mediated afferent arteriolar vasodilation. In additional studies, renal microvessels were isolated and incubated with bradykinin and samples were analyzed by NICI/GC/MS. Under control conditions, renal microvascular EET levels averaged 49 +/- 9 pg/mg/20 min (n = 7). In the presence of bradykinin, EET levels were significantly higher and averaged 81 +/- 11 pg/mg/20 min (n = 7). These data support the concept that EETs are EDHFs and contribute to the nitric oxide-independent afferent arteriolar vasodilation elicited by bradykinin.

Enhanced renal microvascular reactivity to angiotensin II in hypertension is ameliorated by the sulfonimide analog of 11,12-epoxyeicosatrienoic acid

OBJECTIVES

Epoxygenase metabolites produced by the kidney affect renal blood flow and tubular transport function and 11,12-epoxyeicosatrienoic acid (11,12-EET) has been putatively identified as an endothelium-derived hyperpolarizing factor. The current studies were performed to determine the influence of 11,12-EET on the regulation of afferent arteriolar diameter in angiotensin II-infused hypertensive rats.

MATERIALS AND METHODS

Male Sprague-Dawley rats received angiotensin II (60 ng/min) or vehicle via an osmotic minipump. Angiotensin II-infused hypertensive and vehicle-infused normotensive rats were studied for 2 weeks following implantation of the minipump. Renal microvascular responses to the sulfonimide analog of 11,12-EET (11,12-EET-SI) and angiotensin II were observed utilizing the in-vitro juxtamedullary nephron preparation. Renal cortical epoxygenase enzyme protein levels were quantified by Western blot analysis. Renal microvessels were also isolated and epoxygenase metabolite levels measured by negative ion chemical ionization (NICI)/gas chromatography-mass spectroscopy.

RESULTS

Systolic blood pressure averaged 118 +/- 2 mmHg prior to pump implantation and increased to 185 +/- 7 mmHg in rats infused with angiotensin II for 2 weeks. Afferent arteriolar diameters of 2-week normotensive animals averaged 22 +/- 1 microm. Diameters of the afferent arterioles were 17% smaller in hypertensive rats (P< 0.05); however, arterioles from both groups responded to 11,12-EET-SI (100 nmol) with similar 15-17% increases in diameter. As we previously demonstrated, the afferent arteriolar reactivity to angiotensin II was enhanced in angiotensin II-infused animals. Interestingly, elevation of 11,12-EET-SI levels to 100 nmol reversed the enhanced vascular reactivity to angiotensin II associated with angiotensin II hypertension. Renal microvascular EET levels were not different between groups and averaged 81 +/- 9 and 87 +/- 13 pg/mg per 30 min in normotensive and hypertensive animals, respectively. Renal cortical microsomal levels of the epoxygenase CYP2C23 and CYP2C11 proteins were also similar in normotensive and angiotensin II hypertensive rats.

CONCLUSIONS

Taken together, these data support the concept that renal microvascular 11,12-EET activity and levels may not properly offset the enhanced angiotensin II renal vasoconstriction during angiotensin II hypertension.

Identification of epistatic interactions involved in non-insulin-dependent diabetes mellitus in the Otsuka Long-Evans Tokushima Fatty rat

The Otsuka Long-Evans Tokushima Fatty (OLETF) rat is an animal model for obese-type non-insulin-dependent diabetes mellitus (NIDDM) in humans. Our present investigation was designed to identify epistatic interactions influencing NIDDM by performing least squares analysis of variance of all pairs of informative markers in 160 F2 progenies bred from an intercross of OLETF and Fischer-344 rats. We identified four interactions between Nidd15/of (chromosome 7) and Nidd16/of (chromosome 14), Nidd15/of and Nidd17/of (chromosome 15), Nidd16/of and Nidd18/of (chromosome 15), and Nidd16/of and Nidd19/of (chromosome 17), which account for a total of approximately 40% of the genetic variation of entire glucose levels after glucose challenge in the F2. The Nidd16/of locus, which is involved in three of four digenic interactions, and the Nidd19/of are likely to correspond to Nidd2/of and Nidd14/of, NIDDM loci previously identified in the F2 by single-QTL model and multiple-QTL model, respectively, while Nidd15/of, Nidd17/of and Nidd18/of loci reflect novel NIDDM loci. An aberrant increase of the entire glucose level due to synergism occurs in the double OLETF homozygote genotype of Nidd15/of and Nidd16/of, and of Nidd16/of and Nidd19/of, as well as in the OLETF homozygote genotypes of Nidd15/of and Nidd16/of, respectively, combined with the heterozygote genotypes of Nidd17/of and Nidd18/of. These findings demonstrate that inter-allelic interactions are likely to be an important component of NIDDM susceptibility.

Local structures of mechanically alloyed Fe100-xCux solid solutions studied by X-ray absorption fine structure

The local structures of the immiscible Fe(100-x)Cu(x) alloys (x= 0, 10, 20, 40, 60, 80 and 100) produced by mechanical alloying have been investigated by XAFS. For the Fe(100-x)Cu(x) (x > or = 40) solid solutions, the local structures around Fe atoms change from bcc structure to fcc one and the Cu atoms maintain the original coordination geometry after milling for 160 hours. On the contrary, the local structures around Cu atoms in both of Fe80Cu20 and Fe90Cu10 alloys appear a transition from fcc to bcc structure. We found that the Debye-waller factor sigma of fcc Fe-Cu phase is larger than that of bcc Fe-Cu phase, and the sigma (0.099 A) around Fe atoms is larger than that (0.089 A) of Cu in the Fe(100-x)Cu(x) (x > or = 40) solid solutions. This suggests that the mechanically alloyed Fe(100-x)Cu(x) supersaturated solid solution is not a homogeneous alloy, and consists of Fe-rich and Cu-rich regions for various compositions. A possible mechanism for bcc-to-fcc and fcc-to-bcc changes in Fe(100-x)Cu(x) solid solutions is discussed in relation to the interdiffusion and transition induced by the ball milling.

Local structure evolution of FexNi77-xCu(1-)Nb2P14B6 soft magnetic materials by mechanical alloying

Mechanically alloyed Fe(x)Ni77-xCu1Nb2P14B6 soft magnetic materials have been prepared with different atomic compositions. The alloy structures are investigated by X-ray absorption fine structure (XAFS). The results show that mechanical alloying (MA) can drive the Fe(x)Ni77-xCu1Nb2P14B6 powder mixture to produce amorphous alloy while the atomic concentration of Fe element is about and over 40%. On the contrary, the MA Fe(x)Ni77 xCu1Nb2P14B6 is a solid solution with a fcc-like structure in the region of lower Fe atomic concentration (<22%), preserving a medium-range order around Ni and Fe atoms. Moreover, we have found that the local structure geometry of Fe atom is similar to that of Ni atom for all the MA Fe(x)Ni77-xCu1NbP14B6 samples. It indicates that the local structures of Fe and Ni atoms in a Fe(x)Ni77-xCu1Nb2P14B6 sample only depend on the x value of element Ni after ball milling.

Receptor activator of nuclear factor-kappa b ligand activates nuclear factor-kappa b in osteoclast precursors

Receptor activator of nuclear factor-kappa B ligand [RANK ligand (RANK-L)] stimulates mature osteoclasts to resorb bone, a process associated with NF-kappa B activation. RANK-L also prompts macrophages to develop the osteoclast phenotype. Although NF-kappa B is essential for osteoclast differentiation, it is not known whether RANK-L activates this transcription complex in osteoclast precursors. We report that RANK-L rapidly induces NF-kappa B activation in both authentic osteoclast precursors, namely bone marrow macrophages, and RAW 264.7 cells, a murine macrophage line also capable of RANK-L-mediated osteoclastogenesis. Supershift studies reveal the RANK-L-induced DNA binding moiety contains p50/p65, the most common NF-kappa B complex. Subcellular translocation of p50 and p65 subunits is confirmed by Western blots and immunofluorescence analysis. RANK-L activates NF-kappa B in both bone marrow macrophages and RAW 264.7 cells by serine phosphorylation of I kappa B alpha within 5 min, resulting in rapid I kappa B alpha degradation and resynthesis. Attesting to function, RANK-L treatment of RAW 264.7 cells transiently transfected with a plasmid containing NF-kappa B consensus elements linked to luciferase greatly enhances reporter activity. Our data suggest that activation of the NF-kappa B pathway is an integral component of RANK-L-induced osteoclast differentiation.

A p74 common gamma receptor chain isoform facilitates IL-2 and IL-15 responses by the myelomonocytic cell line Tf-1beta2

Functional forms of the IL-2, IL-4, IL-7, IL-9, and IL-15 receptors require the gamma c receptor component. We have described previously a myeloid cell line called Tf-1beta, which binds IL-2 with intermediate-affinity and proliferates in response to IL-2. In this study, we characterize gamma c expression on Tf-1beta2 cells, a derivative of Tf-1beta cells stimulated exclusively with IL-2. Although Tf-1beta2 cells bind IL-2 with intermediate-affinity and proliferate in response to IL-2, this cell line does not express the p64 gamma c chain at the protein level. This result was surprising because prior studies suggest these cells should not be expected to proliferate in response to IL-2 or IL-15 in the absence of the p64 gamma c chain. A p74 protein was detected by western blot following immunoprecipitation with an anti-gamma c polyclonal antibody, and a p74 protein was identified consistently in complex with IL-2 and IL-15 on these cells. However, the gamma c gene in these Tf-1beta2 cells shows no evidence of mutation by sequence analysis. Furthermore, inhibition of glycosylation of these Tf-1beta2 cells by tunicamycin treatment yields a standard 39-kDa molecule recognized on western blot with anti-gamma c antibody, as seen for the standard 64-kDa isoform of gamma c. These results demonstrate that a 74-kDa gamma c receptor isoform was involved in the response of the Tf-1beta2 cells to cytokines which normally interact with the 64-kDa gamma c chain.

Annealed crystallization of ultrafine amorphous NiB alloy studied by XAFS

XAFS has been used to investigate the local structure evolutions of ultrafine amorphous NiB alloy during the annealed crystallization process. A nanocrystalline Ni phase with the local structure of crystalline Ni-like and a crystalline Ni3B, have been produced for ultrafine amorphous NiB alloy under the annealed temperature of 573 K. The results rule out Rojo et al.'s devitrification mechanism of Ni80B20 amorphous alloy in which they considered that an amorphous pure Ni phase is formed in the first exothermic process. However, our results are almost identical with Riveiro et al.'s conclusion in which the intermediate state is interpreted as two metastable crystalline phases of Ni3B and Ni-rich NiB alloy. With the annealed temperature going onto 773 K, the ultrafine NiB sample is further decomposed and crystallized into crystalline Ni with long-range order.

Local structures of nanocrystalline GaN studied by XAFS

X-ray absorption fine structure (XAFS) was used to investigate the local structures around Ga atoms in the hexagonal nanocrystalline and crystalline GaN under 78 and 300 K. For the first nearest neighbor coordination shell of Ga-N. the average bond length R (0.194 nm), coordination number N (4.0), thermal disorder sigma (0.0052 nm) and static disorder sigmaS (0.0007 nm) are neatly independent of the measured temperature and crystalline state. This indicates that the Ga-N covalent bond is much stronger, and the 4 nitrogen atoms in first nearest neighbor around Ga atoms keep the tetrahedral structure (Td). For the second nearest neighbor coordination shell of Ga-Ga, their bond lengths are about 0.318 nm. However, the sigmaS (0.0057 nm) of nanocrystalline GaN is 0.0047 nm larger than that of crystalline GaN (0.001 nm), and the sigmaT of nanocrystalline is 0.0053 nm and 0.0085 nm at the temperature of 78 and 300 K, respectively. The result indicates that the difference of local structure around Ga atoms between nanocrystalline and crystalline GaN occurs mainly at the Ga-Ga second nearest-neighbor coordination shell. The reason is explained as the local lattice distortion and unsaturated surface atoms existing in nanocrystalline GaN.

U7C beamline and XAFS station of national synchrotron radiation laboratory

The XAFS station on beamline U7C of National Synchrotron Radiation Laboratory (NSRL) was completely constructed in December 1998. The source for XAFS station is from a 3-pole superconducting wiggler with magnetic field of 6 T inserted in the straight section of the storage ring. Using a Si(111) double crystal monochromator with a fixed slit, the X-ray intensity at the sample position is about 3x10(9) photons/second at the energy of 8980 eV of Cu K-edge. The Keithley 65 17 electrometers are used to record the electron charges that are produced in the ionization chambers. A high ratio of signal to noise has been obtained for the XAFS spectra of Cu, Ni and Fe foils. Furthermore, the XAFS spectrum of Cu foil in NSRL is in good agreement with that obtained in BSRF and KEK.

A modest reduction in c-myc expression has minimal effects on cell growth and apoptosis but dramatically reduces susceptibility to Ras and Raf transformation

Dergulation of c-myc and mutation of ras genes is commonly found in many human tumors. Several lines of evidence indicate that c-Myc and oncogenic Ras cooperate in causing malignant transformation, but the mechanism of this cooperation is not understood. We set out to investigate the effect on transformation of a modest reduction in endogenous c-Myc expression, which was achieved using a c-myc heterozygous cell line constructed by targeted homologous recombination. In contrast to previous reports where c-Myc expression or activity was ablated using antisense or dominant-defective methods, use of c-myc +/- cells provides a stable and homogeneous cell culture system with a precisely defined c-Myc expression level. In addition, this approach does not suffer from nonspecific artifacts such as antisense oligonucleotide toxicity or interference of dominant-defective proteins with multiple (and often undefined) target proteins. The striking and unexpected finding communicated here is that the relatively modest 50% reduction in c-Myc expression resulted in a greater than 10-fold reduction in susceptibility to transformation by oncogenic Ras or Raf proteins. This very significant defect in transformation potential cannot be explained on the basis of a generalized cell-cycle defect, because c-myc +/- cells exhibit only a minimal (20%) reduction in proliferation. Genetic epistasis analysis indicated that c-Myc and Ras acted by independent pathways that converged to regulate the abundance of the cyclin-dependent kinase inhibitor protein p27Kip1. Anchorage deprivation elicited a strong up-regulation of p27, and a 50% reduction in c-Myc expression significantly compromised the ability of Ras to down-regulate p27. We propose that Ras and c-Myc signals cooperate to regulate the activity of cyclin D-Cdk4/6 complexes: the former by up-regulating the expression of cyclin D1 and the latter by affecting the activity of the complexes. Ectopic expression of cyclin A restored the transformation potential of c-myc +/- cells, implicating it as a downstream genetic component in the pathway. From a therapeutic standpoint, it is of interest that, although transformation appears to be very sensitive to c-Myc expression levels, much larger reductions can be tolerated without causing any significant cell cycle defects.

Biochemical basis for depressed serum retinol levels in transthyretin-deficient mice

Transthyretin (TTR) acts physiologically in the transport of retinol in the circulation. We previously reported the generation and partial characterization of TTR-deficient (TTR(-)) mice. TTR(-) mice have very low circulating levels of retinol and its specific transport protein, retinol-binding protein (RBP). We have examined the biochemical basis for the low plasma retinol-RBP levels. Cultured primary hepatocytes isolated from wild type (WT) and TTR(-) mice accumulated RBP in their media to an identical degree, suggesting that RBP was being secreted from the hepatocytes at the same rate. In vivo experiments support this conclusion. For the first 11 h after complete nephrectomy, the levels retinol and RBP rose in the circulations of WT and TTR(-) mice at nearly identical rates. However, human retinol-RBP injected intravenously was more rapidly cleared from the circulation (t(12) = 0.5 h for TTR(-) versus t(12) >6 h for WT) and accumulated faster in the kidneys of TTR(-) compared with WT mice. The rate of infiltration of the retinol-RBP complex from the circulation to tissue interstitial fluids was identical in both strains. Taken together, these data indicate that low circulating retinol-RBP levels in TTR(-) mice arise from increased renal filtration of the retinol-RBP complex.

[The toxicity variation of organic extracts in drinking water treatment processes]

Source water samples and outlet water samples from different treatment processes of the Beijing Ninth Water Works were concentrated in situ with XAD-2 filled columns. GC-MS analysis and toxic assessment including acute toxicity evaluation by luminescent bacterium bioassay(Q67 strains) and mutagenicity assessment by Ames test(TA98 and TA100 strains with and without S9 addition) were conducted on these samples. The results showed that prechlorination caused the direct and indirect frame shift mutagenicity as well as indirect base pair substitute mutagenicity. Addition of coagulant may increase the base pair substitute mutagenic effects greatly. Sand and coal filtration and granular activated carbon filtration could effectively remove most of the formed mutagens. The rechlorination do not obviously increase the mutagenic effects. No mutagenic effect was observed in tap water. Acute toxicity showed the same variation with that of mutagenicity during the treatment processes. Sample from flocculation treatment process was found to be the most toxic sample. Results of GC-MS analysis showed that water in this plant was not contaminated by PCB. Concentrations of toluene, naphthalene and phenol increased in flocculation treatment process and in tap water. However, the concentrations of these substances were at the level of microgram/L, therefore, were not high enough to cause mutagenicity.

[Effects of adhesive proteins on endothelialization of PC crosslinking yak pericardial materials--an experimental study]

To investigate the conditions of endothelialization of biomaterials, we examined in vitro the growth properties of endothelial cells on PC treated yak pericardial materials. After rinsed in normal saline (0.9%), the surface of PC crosslinking yak pericardial materials was precoated with three kinds of adhesive proteins--Laminin (La), Fibronectin(FN) and Collagen-I(CL-I). Ednothelial cells(EC) from the canine were seeded on the precoated materials, and on the uncoated materials as control. The result showed that in the La and FN groups the seeded EC survived and grew on the patches, while in the CL-I group and uncoated group the seeded EC on and around the patches did not continue to live. Conclusively, in this experiment, PC yak pericardial materials had cytotoxicity; the cytotoxicity of PC crosslinking yak pericardial materials could be decreased by La and FN precoating; La and FN promoted the adhesion and growth of EC on the PC yak pericardial materials patches; the materials met the needs of endothelialization in vitro, prominently in the La group; there was significant difference in endothelialization between La and FN groups (P < 0.05); CL-I had no part in promoting EC adhesion and growth.

Retinoblastoma protein activation of interleukin 8 expression inhibits tumor cell survival in nude mice

Loss of retinoblastoma protein (Rb) has been implicated in the formation of a variety of human malignancies. Restoration of Rb expression in the cell lines representing these tumors eliminates or significantly reduces tumorigenicity in nude mice, but the mechanism for this Rb effect is unknown. Results from this study indicated that Rb expression reduced tumor cell survival in nude mice by dramatically enhancing interleukin 8 (IL-8) secretion. IL-8 secreted by the Rb-transformed cells attracted neutrophils in vitro and tumor-infiltrating neutrophils in vivo, which is consistent with the Rb-mediated tumor regression being dependent on IL-8. The apparent, contradictory roles of IL-8 as a protumorigenic and antitumorigenic cytokine are discussed.

Genetic evidence for obesity loci involved in the regulation of body fat distribution in obese type 2 diabetes rat, OLETF

The Otsuka Long-Evans Tokushima Fatty (OLETF) rat is an animal model for obese type 2 diabetes in human. Obesity is essential for the onset of type 2 diabetes in this rat. Our present investigation was designed to identify quantitative trait loci (QTLs) contributing to obesity by performing a whole-genome search using 214 F(2) intercross progeny between OLETF and F344 rats. We have identified six QTLs responsible for adiposity indices of fat pads on rat chromosomes 2 (Obs1 for mesenteric fat), 4 (Obs2 for retroperitoneal fat), 8 (Obs3 for mesenteric fat), 9 (Obs4 for retroperitoneal fat), and 14 (Obs5 and Obs6 for retroperitoneal fat), demonstrating that the adiposity indices of individual fat pads were under the control of different genes. As expected, the OLETF allele corresponds to increased adiposity indices for all QTLs, except for Obs3, in which the F344 allele leads to an increase in the index.

Pivotal role of phosphoinositide-3 kinase in regulation of cytotoxicity in natural killer cells

The mitogen-activated protein kinase-extracellular signal-regulated kinase signaling element (MAPK-ERK) plays a critical role in natural killer (NK) cell lysis of tumor cells, but its upstream effectors were previously unknown. We show that inhibition of phosphoinositide-3 kinase (PI3K) in NK cells blocks p21-activated kinase 1 (PAK1), MAPK kinase (MEK) and ERK activation by target cell ligation, interferes with perforin and granzyme B movement toward target cells and suppresses NK cytotoxicity. Dominant-negative N17Rac1 and PAK1 mimic the suppressive effects of PI3K inhibitors, whereas constitutively active V12Rac1 has the opposite effect. V12Rac1 restores the activity of downstream effectors and lytic function in LY294002- or wortmannin-treated, but not PD98059-treated, NK cells. These results document a specific PI3K-->Rac1-->PAK1-->MEK-->ERK pathway in NK cells that effects lysis.

IL-2 induces the association of IL-2Rbeta, lyn, and MAP kinase ERK-1 in human neutrophils

IL-2, first identified as a T cell growth factor, has been proven to activate many cell types including polymorphonuclear neutrophils (PMN3). However, the mechanisms involved in PMN activation, especially the signaling pathways used by the IL-2R, are currently unknown. Here we demonstrate that IL-2 has the ability to induce protein tyrosine kinases in human PMN, and we provide the first evidence that lyn kinase is activated and physically associated with MAP kinase/ERK1. Co-immunoprecipitation experiments with anti-IL-2Rbeta and Western blotting with anti-p53/56lym revealed that lyn protein was present in IL-2R precipitates and that the association of lyn with IL-2Rbeta was markedly elevated by IL-2 stimulation. Furthermore the activity of lyn kinase, evaluated by an in vitro kinase assay with enolase as a substrate, increased following IL-2 stimulation. Another important finding was that, upon IL-2 activation, MAPK/ERK1 was also phosphorylated in PMN. A direct association between lyn and ERK1 was initially demonstrated by co-immunoprecipitation/Western blotting and then definitively proven by the use of a GST-ERK1 fusion protein. We showed that ERK1 binds lyn only in IL-2 stimulated PMN, but not in unstimulated PMN. These results suggest that IL-2 can promote the association of lyn protein tyrosine kinase with IL-2Rbeta as well as the direct binding of MAPK/ERK1 to lyn. The signaling pathway utilized by human PMN in response to IL-2 may thus involve the association of lyn with IL-2Rbeta and the activation process also triggers the recruitment and activation of a specific ERK.

Macrophage-derived dendritic cells have strong Th1-polarizing potential mediated by beta-chemokines rather than IL-12

Monocyte-derived dendritic cells (MDDCs) activate naive T lymphocytes to induce adaptive immunity, effecting Th1 polarization through IL-12. However, little is known about other potential DC Th1 polarizing mechanisms, or how T cell polarization may be affected by DCs differentiating in, or exposed to, a proinflammatory environment. Macrophages (MPhis) are DC precursors abundant in inflamed tissues, lymph nodes, and tumors. Thus we studied the T cell-activating and -polarizing properties of MPhi-derived DCs (PhiDCs). Monocytes were cultured in MPhi-CSF (M-CSF) to produce MPhis, which were then differentiated into DCs following culture with GM-CSF plus IL-4. PhiDCs activated a significant allogeneic MLR and were significantly better than MDDCs in activating T cells with superantigen. Most strikingly, PhiDCs elicited up to 9-fold more IFN-gamma from naive or Ag-specific T cells compared with MDDCs (with equivalent IL-4 secretion), despite producing up to 9-fold less IL-12. Neutralization of MDDC, but not PhiDC IL-12 significantly inhibited T cell IFN-gamma induction. PhiDCs produced up to 12-fold more beta-chemokines (macrophage-inflammatory protein-1alpha, -1beta, and RANTES) than MDDCs. Ab blockade of CCR5, but not CXC chemokine receptor 4, inhibited T cell IFN-gamma induction by PhiDCs significantly greater than by MDDCs. Thus DCs differentiating from MPhis induce T cell IFN-gamma through beta-chemokines with little or no requirement for IL-12. Myeloid DCs arising from distinct precursor cells may have differing properties, including different mechanisms of Th1 polarization. These data are the first reports of IFN-gamma induction through chemokines by DCs.

Genetic variation in the gene encoding calpain-10 is associated with type 2 diabetes mellitus

Type 2 or non-insulin-dependent diabetes mellitus (NIDDM) is the most common form of diabetes worldwide, affecting approximately 4% of the world's adult population. It is multifactorial in origin with both genetic and environmental factors contributing to its development. A genome-wide screen for type 2 diabetes genes carried out in Mexican Americans localized a susceptibility gene, designated NIDDM1, to chromosome 2. Here we describe the positional cloning of a gene located in the NIDDM1 region that shows association with type 2 diabetes in Mexican Americans and a Northern European population from the Botnia region of Finland. This putative diabetes-susceptibility gene encodes a ubiquitously expressed member of the calpain-like cysteine protease family, calpain-10 (CAPN10). This finding suggests a novel pathway that may contribute to the development of type 2 diabetes.

Direct tumor lysis by NK cells uses a Ras-independent mitogen-activated protein kinase signal pathway

Destruction of tumor cells is a key function of lymphocytes, but the molecular processes driving it are unclear. Analysis of signal molecules indicated that mitogen-activated protein kinase (MAPK)/extracellular regulated kinase 2 critically controlled lytic function in human NK cells. We now have evidence to indicate that target ligation triggers a Ras-independent MAPK pathway that is required for lysis of the ligated tumor cell. Target engagement caused NK cells to rapidly activate MAPK within 5 min, and PD098059 effectively blocked both MAPK activation and tumoricidal function in NK cells. Target engagement also rapidly activated Ras, detected as active Ras-GTP bound to GST-Raf-RBD, a GST fusion protein linked to the Raf protein fragment containing the Ras-GTP binding domain. However, Ras inactivation by pharmacological disruption with the farnesyl transferase inhibitor, FTI-277, had no adverse effect on the ability of NK cells to lyse tumor cells or to express MAPK activation upon target conjugation. Notably, MAPK inactivation with PD098059, but not Ras inactivation with FTI-277, could interfere with perforin and granzyme B polarization within NK cells toward the contacted target cell. Using vaccinia delivery of N17 Ras into NK cells, we demonstrated that IL-2 activated a Ras-dependent MAPK pathway, while target ligation used a Ras-independent MAPK pathway to trigger lysis in NK cells.

Effect of carvedilol in comparison with metoprolol on myocardial collagen postinfarction

OBJECTIVES

We sought to compare the effects of two different beta-blockers, carvedilol and metoprolol, to an angiotensin-converting enzyme (ACE) inhibitor (captopril) on myocardial collagen deposition during healing and ventricular remodeling after myocardial infarction (MI).

BACKGROUND

Beta-adrenergic blockade has been shown to be beneficial post-MI and in chronic heart failure. Carvedilol is a new-generation vasodilating beta-blocker with additional alpha1-adrenoceptor antagonism and an antiproliferative action, but it is not known if it is more beneficial than standard selective beta-blockers.

METHODS

Using a rat model of MI, induced by left coronary ligation, we studied the effects of 11 weeks of therapy with oral carvedilol, metoprolol or captopril on hemodynamics, tissue weights, collagen volume fraction and hydroxyproline content.

RESULTS

Both beta-blockers caused similar decreases in heart rate and LVEDP compared with untreated post-MI rats. At equivalent beta-adrenoceptor blocking doses, however, carvedilol, but not metoprolol, attenuated the increase in collagen content in noninfarcted regions and prevented the increase in right ventricular weight/body weight (all p < 0.05), and its effect was similar to captopril. Metoprolol treatment tended to increase right ventricular weight and heart weight (p < 0.05). There were no differences in infarct size between the groups.

CONCLUSIONS

Long-term treatment with both beta-blockers, as well as an ACE inhibitor, benefited the healing process in rats post-MI. At equivalent myocardial beta-adrenoceptor blocking doses, however, carvedilol significantly reduced myocardial collagen in the noninfarcted myocardium and cardiac hypertrophy in the right ventricle, whereas metoprolol had no effect on myocardial collagen deposition.

93G, a novel sporadic strain of hepatitis E virus in South China isolated by cell culture

The nucleotide sequence of Hepatitis E virus (HEV) serous isolates (G-9 and G-20) from Guangzhou, South China, which has been reported previously, are divergent significantly from those of other reported HEV isolates. In order to investigate more extensively the Guangzhou isolate, the 93G strain was isolated from the faecal sample of the same individual as G-9 by A549 cell culture and identified immunologically and by molecular biological techniques. The results showed that strain 93G could be propagated in an A549 cell line causing cytopathic effects. The viral particles were aggregated by a specific antibody to HEV Chinese Xinjiang strain (87A) observed using immunoelectron microscopy and were similar morphologically to HEV from other sources. In this study, an indirect fluorescent antibody assay was first developed to examine HEV antigen in the infected cells, by immunofluorescence in the cytoplasm and on the surface membrane of the cells. The 58-kDa and 82-kDa native structural proteins of HEV were also identified in this study by Western blotting. The 93G genome showed high homology (93%) with G-9 previously reported but was also as divergent from the Burmese, Mexican, Chinese Xinjiang isolates and the recently reported US-1 isolate, as was G-9. The data presented indicate that 93G propagated in A549 cells, together with its related serum isolate G-9, represents another HEV strain circulating in China and is responsible for some sporadic hepatitis E infections.

Chronic neutropenia mediated by fas ligand

Chronic neutropenia, often associated with rheumatoid arthritis, is a characteristic finding in large granular lymphocyte (LGL) leukemia. The mechanism of neutropenia is not known. Normal neutrophil survival is regulated by the Fas-Fas ligand apoptotic system. We hypothesized that neutropenia in LGL leukemia is mediated by dysregulated expression of Fas ligand. Levels of Fas ligand in serum samples from patients with LGL leukemia were measured with a Fas ligand enzyme-linked immunosorbent assay. The effects of serum from patients with LGL leukemia on apoptosis of normal neutrophils were determined by flow cytometry and morphologic assessment. High levels of circulating Fas ligand were detected in 39 of 44 serum samples from patients with LGL leukemia. In contrast, Fas ligand was undetectable in 10 samples from healthy donors. Serum from the patients triggered apoptosis of normal neutrophils that depended partly on the Fas pathway. Resolution of neutropenia was associated with disappearance or marked reduction in Fas ligand levels in 10 of 11 treated patients. These data suggest that high levels of Fas ligand are a pathogenetic mechanism in human disease. (Blood. 2000;95:3219-3222)

[Troponin T during cardiopulmonary bypass]

OBJECTIVE

To evaluate the effect of cardiopulmonary bypass (CPB) on myocardial troponin T and its clinical significance and relationship to myocardial cell injury.

METHODS

Thirty-seven patients underwent open heart surgery under CPB. The procedures included correction of congenital heart disease in 15 patients, valve replacement in 15, and coronary artery bypass grafting in 7. Blood samples were taken at four different time intervals for assessing a troponin T. Correlative factors including duration of clamping of aorta, dosage of cardioplegic solution, and metabolic acidosis were studied.

RESULTS

When clamping time > 60 minutes, dosage of cardioplegia solution < 10 ml/kg and existing metabolic acidosis, the level of troponin T was significantly increased (P < 0.01).

CONCLUSION

The elevation of troponin T is closely related to cardiopulmonary bypass, especially the duration of clamping of aorta, insufficiency of cardioplegia, and metabolic acidosis.

[Effects of tea polyphenols on cell kinetics and apoptosis of primary cultured rat skin keratinocytes]

In order to study the effects of tea polyphenols on cell growth and apoptosis of primary cultured rat skin keratinocytes, the safe dosage of tea polyphenols was determined by the release of lactate dehydrogenase(LDH). Cell counting(cytometry) and flow cytometry(FCM) were used to estimate the cell growth and the percentages of cells in different cell cycle phases or apoptosis. The results showed that tea polyphenols stimulated the cell growth from G1/G0 to G2/M phase, enhanced the synthesis of DNA(increase S phase) and increased the proliferative index(PI) from 18.17% to 25.62%. Also, it could block the occurrence of apoptosis. It is concluded that tea polyphenols could stimulate the growth of skin keratinocytes through stimulating the synthesis of cell DNA and inhibiting apoptosis.

Exocytotic mechanism studied by truncated and zero layer mutants of the C-terminus of SNAP-25

The highly conserved SNARE proteins, SNAP-25, syntaxin and synaptobrevin, form a tight ternary complex, which is essential for exocytosis. Crystallization of this complex revealed a four-helix bundle with an unusual hydrophilic layer (zero layer) in its center. In order to evaluate the role of this layer in different kinetic components of secretion, we used the Semliki Forest virus (SFV) system to infect adrenal chromaffin cells with SNAP-25 Q174L, a point mutant in the zero layer. Using combined flash photolysis of caged calcium and membrane capacitance measurements, we investigated its effect on the exocytotic burst and sustained phase of exocytosis with high time resolution. Cells expressing SNAP-25 Q174L displayed a selective reduction in the sustained phase, while the two components of the exocytotic burst remained unaffected. Furthermore, the exocytotic response to the second flash was significantly reduced, indicating a decrease in refilling kinetics. We therefore conclude that the zero layer is critical for the formation of SNARE complexes, but that it plays no role in the dynamic equilibrium between the two exocytosis-competent vesicle pools.

[Effects of homoharringtonine on proliferation of human retro-ocular fibroblasts]

This is a study amied at the effects of homoharringtonine on the proliferation of human retro-ocular fibroblasts. The human retroocular fibroblasts (HROFb) were cultured and MTT colorimetry assay was used to determine the proliferation of HROFb. The influence of homoharringtonine on the proliferation of HROFb was observed in vitro. The results showed that MTT colorimetry assay could precisely reflect the proliferation of HROFb. The absorbance was directly proportional to the number of the cells (r = 0.996, P < 0.001). The proliferation of HROFb was inhibited by the homoharringtonine and the cell proliferation percentage was correlated positively to the homoharringtonine level (r = 0.6932, P < 0.001).

Irradiation of rat tubule epithelial cells alters the expression of gene products associated with the synthesis and degradation of extracellular matrix

PURPOSE

To determine the ability of radiation to modulate kidney tubule epithelial cell expression of various molecules involved in regulating extracellular matrix accumulation (collagen types I and III, fibronectin, plasminogen activator-inhibitor 1 (PAI-1), TGF-beta and tissue inhibitor of metalloproteinases-2 (TIMP-2)) and degradation (plasminogen activators u-PA or t-PA, MMP-2 and MMP-9).

MATERIALS AND METHODS

NRK52E rat tubule epithelial cells were placed in serum-free medium 24 h prior to irradiation with single doses of 1.0-10.0 Gy 137Cs gamma-rays. After irradiation, cells were maintained in serum-free medium for up to 48 h.

RESULTS

Irradiation of NRK52E cells was associated with significant dose-dependent increases in collagen I (p<0.05) and PAI-1 (p< or =0.002) mRNA. Collagen III mRNA levels also exhibited a dose-dependent increase; however, this increase failed to reach levels that were statistically significant. Fibronectin mRNA levels were unaltered following irradiation. Radiation also led to an isoform-specific alteration in TGF-beta expression; TGF-beta1 mRNA increased, TGF-beta3 mRNA decreased. The amount of TGF-beta protein secreted into the medium was unchanged following irradiation; however, there was a fivefold increase in the relative amount of active TGF-beta. Irradiation was also associated with differential changes in MMP expression: active MMP-2 levels increased, while MMP-9 levels were unaltered; PA secretion into the medium was unchanged following irradiation.

CONCLUSIONS

Irradiation of rat kidney tubule epithelial cells leads to altered production of various molecules associated with extracellular matrix accumulation and degradation.

Microscopic origin of the phenomenological equilibrium "Doping limit Rule" in n-type III-V semiconductors

The highest equilibrium free-carrier doping concentration possible in a given material is limited by the "pinning energy" which shows a remarkable universal alignment in each class of semiconductors. Our first-principles total energy calculations reveal that equilibrium n-type doping is ultimately limited by the spontaneous formation of close-shell acceptor defects: the (3-)-charged cation vacancy in AlN, GaN, InP, and GaAs and the (1-)-charged DX center in AlAs, AlP, and GaP. This explains the alignment of the pinning energies and predicts the maximum equilibrium doping levels in different materials.

Responses of nitric oxide synthase expression in the gracile nucleus to sciatic nerve injury in young and aged rats

Neuronal nitric oxide synthase (nNOS) is induced in dorsal root ganglion neurons following axotomy in young rats, and is also increased in the gracile nucleus neurons of intact aged rats. The present study examined the influence of sciatic nerve axotomy on nNOS expression in the gracile nucleus in young compared to aged rats. The unilateral transection of the sciatic nerve was performed in young (4 months) and old (24 months) Fischer rats. Sections of rat medulla obtained 14 days after axotomy were immunolabelled using a polyclonal antibody directed against nNOS and stained by nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) histochemistry, a marker of nNOS activity. In young rats, unilateral axotomy produced increased NADPHd containing neurons in the rostral region and the caudal region of the ipsilateral gracile nucleus compared to the side with intact sciatic nerve. In old rats, the NADPHd containing neurons in the ipsilateral gracile nucleus were moderately increased by axotomy over the age changes seen in the contralateral side. Similar results were obtained with nNOS immunoreactivity in young rats, but more cells were seen with NADPHd staining compared to nNOS immunostaining in old rats. The results suggest that unilateral sciatic axotomy causes an increase in nNOS expression in the ipsilateral gracile nucleus of young rats, which is still seen in old rats as an increase over normal aging changes.

[Informatics of dental medicine]

Dental informatics is a newly developed discinpline which is integrated by modern stomatology, computer sciences and informatics. In this paper, the concept, importance, basic principle and contents were discussed in details. The relationship among dental informatics and related sciences, the formation and history of dental informatics were also described in this paper.

Tumor necrosis factor alpha regulates alpha(v)beta5 integrin expression by osteoclast precursors in vitro and in vivo

Early osteoclast precursors, in the form of murine bone marrow macrophages (BMMs), while expressing no detectable alpha(v)beta3 integrin, contain abundant alpha(v)beta5 and attach to matrix in an alpha(v) integrin-dependent manner. Furthermore, alpha(v)beta5 expression by osteoclast precursors progressively falls as they assume the resorptive phenotype. We find the osteoclastogenic agent, tumor necrosis factor-alpha, (TNF) down-regulates alpha(v)beta5 expression by BMMS via attenuation of beta5 messenger RNA (mRNA) t1/2. Using BMMs from TNF receptor knockout mice we establish the p55 receptor transmits the beta5 suppressive effect. The functional implications of TNF-mediated alpha(v)beta5 down-regulation are underscored by the capacity of an alpha(v) inhibitory peptide mimetic to prevent spreading by BMMs expressing abundant alpha(v)beta5 while failing to impact those in which the integrin has been diminished by TNF. Finally, beta5 mRNA in BMMs of wild-type mice administered lipopolysaccharide (LPS) progressively falls with time of in vivo treatment. Alternatively, beta5 mRNA does not decline in BMMs of LPS-treated mice lacking both TNF receptors, documenting down-regulation of the beta5 integrin subunit, in vivo, is mediated by TNF. Thus, matrix attachment of osteoclast precursors and mature osteoclasts are governed by distinct alpha(v) integrins which are differentially regulated by specific cytokines.

A new locus for late-onset, progressive, hereditary hearing loss DFNA20 maps to 17q25

We report the localization of DFNA20, a gene causing dominant, nonsyndromic, progressive hearing loss in a three-generation Midwestern family, to chromosome 17q25. Affected family members show a bilateral, sloping, progressive, sensorineural hearing loss, first evident at 6000 and 8000 Hz, that can be identified in some family members in the early teens and is clearly evident by the early twenties. As age increases, the degree of hearing loss increases with threshold shifts seen at all frequencies. Linkage to known hereditary hearing loss loci was excluded. A genome-wide screen detected positive linkage to D17S784 (LOD(Z) = 6.62; &theta; = 0). Haplotype analysis refines the DFNA20 critical region to 12 cM between D17S1806 and D17S668. Radiation hybrid mapping with Stanford G3 and TNG panels was used to evaluate the genes ACTG1, GRIN2C, FKHL13, P4HB, SPARC, and ARHGDIA as candidates for DFNA20.

Proteolytic enzymes as a limitation for pulmonary absorption of insulin: in vitro and in vivo investigations

In vitro biodegradation of insulin in lung cytosol and subcellular pellets of normal and diabetic rats was investigated. Rat lung was homogenized and subcellular fractions were isolated by ultracentrifugation. Degradations of [125I]-insulin after incubation with lung cytosol or subcellular pellets was determined using the trichloroacetic acid method. The results show that insulin is highly degraded in cytosol and subcellular pellets. Cytosolic insulin degradation was strongly inhibited by bacitracin or sodium cholate. The degradation of insulin in the lung cytosol from diabetic rats was significantly less than from normal rat. The lung protease activity reached a maximum at pH 7.4. Enzyme inhibitors like bacitracin and sodium cholate noticeably enhanced the relative pharmacological bioavailability of insulin when given intratracheally with insulin to normal rats. Acidic insulin solutions (pH 3.0) had more pronounced hypoglycaemic effects than neutrol solution (pH 7.0). These in vitro and in vivo results suggest that the proteolytic enzymes in the lung limit pulmonary delivery of insulin. The coadministration of protease inhibitors would be a useful approach for improving the pulmonary absorption of insulin.

Identification of novel non-insulin-dependent diabetes mellitus susceptibility loci in the Otsuka Long-Evans Tokushima fatty rat by MQM-mapping method

The Otsuka Long-Evans Tokushima Fatty (OLETF) rat is an animal model for obese-type, non-insulin-dependent diabetes mellitus (NIDDM) in humans. We have previously identified 11 quantitative trait loci (QTLs) responsible for NIDDM susceptibility on Chromosomes (Chrs) 1, 5, 7, 8, 9, 11, 12, 14, and 16 (Nidd1-11/of for Non-insulin-dependent diabetes 1-11/oletf) by using the interval mapping method in 160 F(2) progenies obtained by mating the OLETF and the Fischer-344 (F344) rats. MQM-mapping, which was applied for QTL analysis based on multiple-QTL models, is reported to be more powerful than interval mapping, because in the process of mapping one QTL the genetic background, which contains the other QTLs, is controlled. Application of MQM-mapping in the F(2) intercrosses has led to a revelation of three novel QTLs on rat Chrs 5 (Nidd12/of), 7 (Nidd13/of), and 17 (Nidd14/of), in addition to Nidd1-11/of loci. The three QTLs, together with the Nidd1-11/of, account for a total of approximately 70% and approximately 85% of the genetic variance of the fasting and postprandial glucose levels, respectively, in the F(2). While the OLETF allele corresponds with increased glucose levels as expected for Nidd12 and 14/of, the Nidd13/of exhibits heterosis: heterozygotes showing significantly higher glucose levels than OLETF or F344 homozygotes. There is epistatic interaction between Nidd2 and 14/of. Additionally, our results indicated that the novel QTLs could show no linkage with body weight, but Nidd12/of has an interaction with body weight.

Identification of a locus for susceptibility to renal cell carcinoma in the Long-Evans Cinnamon rat

The Long-Evans Cinnamon (LEC) mutant rat shows higher incidence of renal cell carcinomas induced by a treatment with the chemical carcinogen N-diethylnitrosamine, as compared to the normal control rat. We performed the first genome-wide scan for genes responsible for susceptibility to chemically induced renal cell carcinoma in an F2 intercross obtained by mating the LEC and Fischer-344 (F344) rats. The genotype of 71 (F344 x LEC) F2 progenies was determined with the use of 338 simple sequence length polymorphisms (SSLPs) spread over the genome. The F2 rats which carried renal cell carcinoma were shown to possess the incidence of homozygosity of the LEC allele which is higher than that of the other genotypes at SSLP markers on chromosome 5 (chi2 = 17.5 for D5Rat21). Our linkage analysis has led to the revelation of a novel gene that influences susceptibility to renal cell carcinoma on rat chromosome 5.

[Wavelength selection in management of central serous chorioretinopathy]

OBJECTIVE

To compare the effects of three kinds of laser wavelength in management of central serous chorioretinopathy (CSCR).

METHOD

89 patients with CSCR were randomly divided into three groups according to different wavelengths used. Visual acuity, fundus, fundus fluorescein angiography (FFA), light sensitivity, central visual field were performed before and after laser therapy.

RESULT

Compared with red and green wavelength groups, in yellow group the visual acuity, light sensitivity were improved more significantly (P < 0.05), and the disease course was shortened, the effects in recurrence rate were similar in the three wavelength groups.

CONCLUSION

In the three kinds of waves, yellow and red have similar and positive effects in the treatment of CSCR.

Cell culture of sporadic hepatitis E virus in China

The isolation and identification of the 87A strain of epidemic hepatitis E virus (HEV) by means of cell culturing have been described previously. This paper reports the successful isolation of a sporadic HEV strain (G93-2) in human lung carcinoma cell (A549) cultures. The etiology, molecular and biological properties, and serological relationship of this new strain to other, epidemic HEV strains are described. The propagation of both sporadic and epidemic HEV strains in a cell culture system will facilitate vaccine research.

A multihit, multistage model of chemical carcinogenesis

Carcinogenesis involves the accumulation of genetic changes within a single cell. Tumor promotion functions in the initial clonal expansion of an initiated cell but is generally not considered to influence later stages. To investigate whether tumor promotion can influence later stages of carcinogenesis we developed a two-hit 7, 12-dimethylbenz[a]anthracene (D) protocol designed to enrich for keratinocytes that contain at least two D-induced genetic alterations. FVB/N mice were initiated with D and promoted with 12-O-tetradecanoylphorbol-13-acetate (T) or treated with acetone (A) vehicle for 6 weeks. At 7 weeks after the start of promotion, but before visible papilloma development, groups of mice were treated with a second dose of D or A and 1 week later T promotion was resumed. D/T/A/T mice developed 2.8 papillomas/mouse and D/A/D/T mice demonstrated an additive tumor response and developed 5.8 papillomas/mouse. Importantly, D/T/D/T mice developed 12.4 papillomas/mouse, thereby demonstrating a synergistic tumor response compared with D/A/D/T and D/T/A/T mice. D/T/D/T papillomas exhibited increases in suprabasal S phase cells and keratin 13 expression when compared with D/T/A/T papillomas. D/T/D/T mice developed squamous cell carcinomas (SCCs) 10 weeks earlier than D/T/A/T mice and demonstrated a 96% malignancy incidence and 1.71 SCC/mouse compared with D/T/A/T mice, which demonstrated a 28% malignancy incidence and 0.32 SCC/mouse. Greater than 90% of D/T/A/T and D/T/D/T papillomas and SCCs contained mutant Ha-ras, while a normal Ha-ras allele persisted in all cases, indicating that a gene other than the remaining normal allele of Ha-ras was a target gene for the second D hit. These data demonstrate that: (i) promotion between the first and second hits has a profound outcome on carcinogenesis, presumably by increasing the probability that a second hit will occur in a previously initiated cell; (ii) continued promotion after the second hit is required for full expression of malignancy; (iii) the classic initiation-promotion protocol can be extended to a multihit, multistage model.

Radiation-induced changes in nucleotide metabolism of two colon cancer cell lines with different radiosensitivities

PURPOSE

To investigate changes in nucleotide metabolism after irradiation.

MATERIALS AND METHODS

HT29 and SW48 human colon carcinoma cells were exposed to 60Co gamma-rays at doses ranging from 0 to 7.5 Gy. At different times after irradiation, the activities of nine enzymes involved in nucleotide metabolism were measured, the levels of thymidine kinase and deoxycytidine kinase proteins were evaluated by Western blot, and cell-cycle kinetics were analysed by flow cytometry.

RESULTS

Changes in enzyme activities concerned not purine but pyrimidine metabolism and essentially the salvage pathway for deoxyribonucleotide synthesis. They were greater in the less radiosensitive HT29 cells. The levels of thymidine kinase and deoxycytidine kinase proteins changed in parallel with their activities. The metabolic changes in irradiated cells did not seem to be due to S-phase transition and the pattern of enzyme activity changes was different from that observed in proliferative cells.

CONCLUSIONS

Radiation-induced changes in the salvage pathway for pyrimidine deoxyribonucleotide synthesis were observed. These findings could be exploited in cancer therapy because higher enzyme activities after irradiation suggest that radiation exposure may render cells more sensitive to the drugs activated by these enzymes.

Purine metabolism in two human melanoma cell lines: relation to proliferation and differentiation

Purine nucleotide metabolism was studied in two human cutaneous melanoma cell lines IPC182 and IGR221. IPC182 cells do not differentiate, while IGR221 cells differentiate spontaneously at confluency, with intense melanin production. The activities of 11 enzymes involved in the de novo or salvage synthesis or the catabolic pathway of purine nucleotides were measured at different times (from day 3 to day 18), after subculture, during exponential growth and the stationary phase, with or without differentiation. The results demonstrated remarkable differences in the enzyme activity levels and/or the evolution from exponential growth to the stationary phase for each cell line, as well as between the two cell lines. In the non-differentiating IPC182 cells, the activity of enzymes involved in purine nucleotide synthesis decreased when the growth rate slowed down and remained at a low level with a concomitant increase in catabolic activities. In the differentiating IGR221 cells, the activity of enzymes involved in purine nucleotide salvage synthesis increased during the proliferative phase and was maintained at a high level when the cells reached confluency and differentiated; catabolic activities were always lower than in the IPC182 cells. This suggests that extra purine nucleotides, synthesized preferentially by the salvage pathway, could be required for the differentiation of human melanoma cells. Since the two cell lines were cultured in the absence of any differentiation-inducing agents, these results indicate that various metabolic modifications are associated with the natural processes of cell proliferation and differentiation. This research could help to identify some of the enzymes involved in purine metabolism as the targets for the induction of differentiation.

An efficient multiplex PCR suitable for large scale typing in linkage mapping

The dissection of polygenic traits is made possible with the development of microsatellite markers. Linkage study of this kind involves many markers with tens of hundreds of samples. Although typing essentially contains only two steps: PCR amplification and gel electrophoresis. Such work is still heavy when a large number of samples had to be genotyped. Multiplex PCR may reduce the work, but one has to optimize the conditions from marker to marker. Here we describe a dye-compatible multiplex PCR that works under standardized condition without the need to pre-determine the combinational primer concentration and the time-consuming step to mix many samples with gel loading dye before electrophoresis. This successful protocol should greatly reduce the cost and labor for genetic study of polygenic traits.

[Determination of cortisol in plasma and 24-hour urine of patients with central serous chorioretinopathy]

OBJECTIVE

To study the cortisol levels in patients with central serous chorioretinopathy (CSCR).

METHODS

Endogenous cortisol levels in plasma and urine were determined in 44 patients with CSCR by radioimmunoassay and chromatography, and their results were compared with that of 41 controls.

RESULTS

In acute CSCR, the mean values of the plasma cortisol (296.53 +/- 77.03) ng/ml and 24-hour urine 17-hydroxysteroids (the major metabolite of cortisol metabolism) (12.08 +/- 4.82) mg/24 h revealed significantly higher values in the patient group (P < 0.05).

CONCLUSIONS

Increased levels of endogenous cortisol play a role in the development of CSCR.

Retinoblastoma protein expression leads to reduced Oct-1 DNA binding activity and enhances interleukin-8 expression

Tumor cell lines with a defective retinoblastoma gene are unable to transcribe the HLA class II genes in response to IFN-gamma treatment, and reconstitution of functional Rb rescues IFN-gamma-induced class II gene expression. However, the molecular mechanism of Rb rescue of the class II genes is unknown. We have examined the effect of Rb expression on the activation of the promoter for HLA-DRA, the prototype class II gene. Oct-1, a POU domain transcription factor, was identified as a repressor of HLA-DRA promoter activity in the Rb-defective cells. Rb expression led to phosphorylation of Oct-1, thus relieving its repressive effect. Oct-1 has also been shown to repress interleukin 8 promoter activity. Consistent with reduced levels of Oct-1 DNA binding activity in the Rb-transformed cell lines, interleukin 8 expression is higher in these cell lines.

[A pair-matched comparison and follow-up study of patients with euthytroid Graves ophthalmopathy and patients with hyperthyroid graves ophthalmopathy]

This study was intended to acquire a knowledge about the similarity and difference between euthyriod Graves ophthalmopathy (EGO) and hyperthyroid Graves ophthalmopathy (HGO), and about the outcome of the EGO cases. Twenty-seven EGO patients were pair-matched with 27 HGO patients, and 18 of the EGO patients were followed up for 1-6 years. The results showed that the EGO group had markedly more patients with diplopia, failure to close lids, limitation of eyeball movements, cornea involvement, and more patients with a difference of two eyes' exophthalmos degrees > or = 2 mm, but the HGO group had more patients with optic nerve involvement. No significant difference was found between the two groups' ophthalmopathic indexes by using the t-test. Drug therapy of the EGO group was more efficacious than that of the HGO group. The results of follow-up study showed that 61% of the EGO cases had hyperthyroidism and goiter within 5 months to 3 years, but 39% of the cases had no hyperthyroidism up to 6 years. These data suggest that EGO is associated with thyroid diseases and it can stand "alone" as an auto-immune disease.