Truncation of Kir6.2 produces ATP-sensitive K+ channels in the absence of the sulphonylurea receptor

ATP-sensitive potassium channels (K-ATP channels) couple cell metabolism to electrical activity and are important in the physiology and pathophysiology of many tissues. In pancreatic beta-cells, K-ATP channels link changes in blood glucose concentration to insulin secretion. They are also the target for clinically important drugs such as sulphonylureas, which stimulate secretion, and the K+ channel opener diazoxide, which inhibits insulin release. Metabolic regulation of K-ATP channels is mediated by changes in intracellular ATP and Mg-ADP levels, which inhibit and activate the channel, respectively. The beta-cell K-ATP channel is a complex of two proteins: an inward-rectifier K+ channel subunit, Kir6.2, and the sulphonylurea receptor, SUR1. We show here that the primary site at which ATP acts to mediate K-ATP channel inhibition is located on Kir6.2, and that SUR1 is required for sensitivity to sulphonylureas and diazoxide and for activation by Mg-ADP.

Performance consideration of three-dimensional optoelectronic interconnection for intra-multichip-module clock signal distribution

The structure, fabrication, and theory of a three-dimensional planarized optoelectronic clock signal distribution device, based on a thin light-guiding substrate in conjunction with a two-dimensional polymer holographic grating array, are described. We have demonstrated previously a 25-GHz 1-to-42 (6 x 7) highly parallel fan-out interconnect with a signal-to-noise ratio of 10 dB. We present theoretical research that focuses on generating a globally uniform fan-out distribution. An objective function aimed at equalizing the intensities among the fan-out beams is established. For an arbitrary M x N fan-out distribution, there are M + N + 1 sets of holograms needed to be recorded independently to provide the required equal fan-outs. The efficiency of each hologram is determined precisely. The angular misalignment, wavelength dispersion, and spot-size problems are discussed further, together with their tolerance requirements on the size of the photoreceivers integrated on the multichip modules. Employment of 0.25-pitch gradient index (GRIN) lenses as a collimator and as a focusing element is demonstrated experimentally. Optical beam profile manipulation and packaging tolerance are enhanced greatly with GRIN lenses. Finally, clock skew problems associated with the proposed system are discussed, and schemes to minimize the skew are proposed.

Fe- and Co-bleomycins bound to site specific and nonspecific DNA decamers: comparative binding and reactivity of their metal centers

Co- and Fe-bleomycins (Blms) have been reacted with DNAa, d(GGAAGCTTCC)2, containing a specific site for cleavage, and DNAb, d(GGAAATTTCC)2, a closely related nonspecific 10-mer, to survey whether features of structure and reactivity of these adducts vary systematically as a function of the base sequence of the DNA oligomer. The ESR spectrum of NO-Fe(II)BlmDNAa is rhombically perturbed in comparison with that of NO-Fe(II)BlmDNAb, which is nearly identical to the spectrum of NO-Fe(II)Blm. The ESR spectrum of Fe(III)BlmDNAa in phosphate buffer is low-spin; that of Fe(III)BlmDNAb is high-spin as seen with Fe(III)Blm alone. According to absorbance spectroscopy, O2-Fe(II)BlmDNAa is stabilized in comparison with the DNAb adduct. Similar stabilization of O2-Co(II)Blm bound to DNAa but not to DNAb was also observed by ESR spectroscopy. HO2(-)-Co(III)Blm A2 binds in slow exchange on the NMR time scale to DNAa at its 5'-G-pyrimidine-3' site of cleavage. In contrast, fluorescence and NMR spectroscopy demonstrate that most of HO2(-)-Co(III)Blm A2 binds stoichiometrically in fast exchange to DNAb. The reactions of Fe(III)BlmDNAa and Fe(III)BlmDNAb with ascorbate and O2 reveal that the latter becomes activated and cleaves its 10-mer, producing base propenals, at a faster initial rate. Thus, in two series of metallobleomycins, (A) NO-Fe(II)Blm, O2-Fe(II)Blm, Fe(III)Blm in phosphate buffer, and HO2(-)-Fe(III)Blm and (B) O2-Co(II)Blm and HO2(-)-Co(III)Blm, the metal domain of each species interacts differently with DNA depending upon its base sequence.

[Transmission electron microscopic study on eosinophil degranulation in nasal mucosa in allergic rhinitis]

To observe the ultrastructure of eosinophil (EOS) degranulation in nasal mucosa in allergic rhinitis, nasal mucosa biopsies from patients with perennial allergic rhinitis (PAR, n = 13) pollinosis (PS, n = 9) subjects and normal controls (n = 3) were processed and the ultrastructure changes of EOS degranulation were examined under transmission electron microscope and routine histopathological observation. The ultrastructure of EOS degranulation in nasal mucosa collected from PAR and PS patients in their remission period differed from that in their attacking period, though there was no distinct differences in the distribution patterns of EOS. Increased cell membrane projections, eminent cytoplasm vacuolization, inconsistent density of granules with its crystalloid being lost, plus tissue edema and damage of collagen fibers in adjacent areas of degranulating EOS were among the most important ultrastructural changes of EOS in attacking period. The interrelations of EOS, mast cells (MC) and T-lymphocytes play important roles in the pathogenesis of allergic rhinitis.

Serine palmitoyltransferase (scs1/lcb2) mutants have elevated copy number of the L-A dsRNA virus

The microsomal fraction isolated form serine palmitoyltransferase (lcb2/scs1) mutants is enriched in a 90 kDa protein. The protein was identified as the major coat (Gag) protein of the L-A dsRNA virus particles by partial sequencing and by its interaction with anti-Gag antibodies. The total amount of Gag in whole-cell lysates of scs1/lcb2 mutant cells is greater than in wild-type lysates indicating that the enrichment of the protein in the microsomal fraction of scs1/lcb2 mutant cells may result from increased copy number of the L-A dsRNA virus. This is supported by the findings that the mutants also have increased levels of L-A dsRNA. Altered sphingolipid synthesis in the scs1 mutant cells appears to increase the copy number of the L-A viral particles.

Porcine polymorphonuclear leukocytes generate extracellular microbicidal activity by elastase-mediated activation of secreted proprotegrins

Antimicrobial peptides of several structural classes have been found in phagocytes and epithelial cells of many animals. The broadly microbicidal protegrins (PG1, -2, and -3) were originally isolated as 16 to 18-amino-acid peptides from pig neutrophil lysates, but the corresponding cDNA sequences encoded much larger precursors that belonged to the cathelicidin family of antimicrobial peptides. We explored the storage, secretion, and microbicidal activation of protegrins in porcine neutrophils and in a model system consisting of recombinant proprotegrin 3 (pPG3) and various serine proteases and their inhibitors. Protegrins were stored in neutrophils as inactive proforms that were cleaved by neutrophil elastase to mature protegrins during the preparation of granule lysate and during phorbol myristate acetate-stimulated granule secretion from intact neutrophils. Recombinant pPG3 was efficiently cleaved by trace amounts of human neutrophil elastase or equivalent amounts of elastase activity from porcine neutrophils, but pPG3 was relatively resistant to porcine pancreatic elastase or human neutrophil cathepsin G. The recombinant pPG3 and neutrophil proprotegrins lacked microbicidal activity, but the mature protegrins generated in the elastase-mediated cleavage reaction were as active against Listeria monocytogenes as the chemically synthesized protegrin. The secretion and elastase-mediated activation of proprotegrins accounted for much of the stable microbicidal activity of porcine neutrophil secretions against L. monocytogenes. Secreted proprotegrins and trace amounts of elastase constitute a binary microbicidal system that is likely to contribute to the antimicrobial activity of porcine inflammatory fluids.

Changes in tachykinin--ergic nerve terminal densities in rat nasal mucosa during hypersensitivity

OBJECTIVE

To further carry out a quantitative immunohistochemical study on neuropeptides (NPs) participation in perennial allergic rhinitis (PAR) in nasal mucosa.

METHODS

By using light microscopy (routine hematoxylin and eosin staining, Wright's staining and 1% toluidine blue staining) and scanning as well as transmission electron microscopy, an exhaustive immunohistochemical and morphometric study was made on the changes of substance P (SP), neuropeptide A (NKA) and neuropeptide B (NKB) in the nasal mucosa of a toluene-2,4-iso-cyanate (TDI)-induced PAR model of rat.

RESULTS

The results showed that the densities of all three peptidergic terminals were significantly increased (P < 0.01) in experimental group (115.72 +/- 28.43 for SP, 39.23 +/- 10.34 for NKA and 37.24 +/- 11.22 for NKB, respectively) as compared with those in control group (49.65 +/- 11.23 for SP, 12.44 +/- 6.21 for NKA and 13.31 +/- 7.60 for NKB, respectively). Increased staining, thickening of peptidergic terminals and enlargement of varicosities were found. Mast cell infiltration in nasal mucosa was in parallel with increase of peptidergic terminals.

CONCLUSION

All results support the hypothesis that NP is a newly-recognized but potentially important factor in the pathogenesis of PAR.

Intraplane to interplane optical interconnects with a high diffraction efficiency electro-optic grating

We report on a new optical interconnect architecture for three-dimensional, multiple electro-optic gratings with LiNbO(3) used in conjunction with substrate guided waves. First the operating mechanism of the system is studied in detail, and the momentum mismatch in the operating process of the system is also demonstrated. We then derive a new method for calculating coupling efficiency by introducing a compensation for the mismatch. This theoretical research allows the new optical interconnect architecture to provide a higher design accuracy and an optimized coupling efficiency, even though it is under the case of momentum mismatch. We achieve this result by introducing a substrate guided wave with 45 degrees bouncing angle and 100-V applied voltage. The successful design and its theoretical analysis will be helpful for research on the grating coupler.

Clavanins, alpha-helical antimicrobial peptides from tunicate hemocytes

Hemocytes from the invertebrate Styela clava, a solitary tunicate, contained a family of four alpha-helical antimicrobial peptides that were purified, sequenced and named clavanins A, B, C and D. Each clavanin contained 23 amino acid residues and was C-terminally amidated. The tunicate peptides resembled magainins in size, primary sequence and antibacterial activity. Synthetic clavanin A was prepared and displayed comparable antimicrobial activity to magainins and cecropins. The presence of alpha-helical antimicrobial peptides in the hemocytes of a urochordate suggests that such peptides are primeval effectors of innate immunity in the vertebrate lineage.

Integrin-mediated regulation of hematopoiesis: do BCR/ABL-induced defects in integrin function underlie the abnormal circulation and proliferation of CML progenitors?

Hematopoiesis takes place in close contact with the marrow microenvironment. Normal progenitors adhere through a variety of receptors to stroma and extracellular matrix components, including fibronectin. Adhesion through integrins to fibronectin may not only serve to anchor progenitors to the microenvironment but also to directly alter the proliferative behavior of normal hematopoietic progenitors. Chronic myelogenous leukemia (CML) is a malignant disease of the hematopoietic stem cell. At the molecular level, CML is characterized by the BCR/ABL gene rearrangement which encodes for the oncoprotein, p210bcr-abl. Presence of the p210bcr-abl tyrosine kinase is necessary and sufficient for the malignant transformation of hematopoietic cells. Clinically, CML is characterized by an abnormal, premature release of primitive progenitors and precursors in the blood and by the continuous proliferation of the malignant progenitor population. In vitro, CML progenitors fail to adhere to or be regulated by marrow stroma. Since CML progenitors express similar numbers of integrin adhesion receptors as normal progenitors, functional rather than quantitative differences of these receptors on CML progenitors may be responsible for the abnormal circulation and proliferation of the malignant clone. In this manuscript we will review the role of integrin adhesion receptors present on normal hematopoietic progenitors in the regulation of their proliferation and discuss signal transduction mechanisms that may be responsible for these effects. We will also discuss the integrin defect in CML which may be caused by the presence of the oncoprotein, P210bcr-abl, and may explain the abnormal trafficking and proliferation observed in CML.

Retarded development of exoerythrocytic stages of the rodent malaria parasite Plasmodium berghei in human hepatoma cells by extracts from Dioncophyllaceae and Ancistrocladaceae species

Retarded development of exoerythrocytic stages of the rodent malaria parasite Plasmodium berghei in human hepatoma cells by extracts from Dioncophyllaceae and Ancistrocladaceae species. International Journal for Parasitology 27: 29-32. Naphthylisoquinoline alkaloid-containing extracts (10 micrograms ml-1) of species belonging to the Dioncophyllaceae and the Ancistrocladaceae, 2 small tropical plant families, display pronounced in vitro activities against exoerythrocytic stages of Plasmodium berghei (Anka), developing in human hepatoma cells (Hep G2). The highest activities were obtained with CH2Cl2 root and bark extracts, and a CH2Cl2/NH3 leaf extract from Triphyophyllum peltatum, a CH2Cl2/NH3 root extract from Ancistrocladus abbreviatus, and a CH2Cl2 leaf extract from A. tectorius. The degrees of growth inhibition ranged within 27.7-70.0%. The commercially available drug primaquine diphosphate (25 micrograms ml-1) caused a comparable effect (62.1%) in the same test system.

Molluscicidal activity of naphthylisoquinoline alkaloids from Triphyophyllum and Ancistrocladus species

The naphthylisoquinoline alkaloids dioncophylline A (1) and 5'-O-demethyl-8-O-methyl-7-epi-dioncophylline A (2) represent a new structural type of molluscicidal compounds and the active principle of extracts of the tropical lianas Ancistrocladus abbreviates and Triphyophyllum peltatum. The activity of 1 was further improved by derivatization.

Clinical observation on efficacy of electro-acupuncture therapy in hyperplasia of mammary glands and its effect on immunological function

Based on our work on electro-acupuncture therapy of hyperplasia of mammary glands and in order to observe further the relationship between immunological function and E2 in hyperplasia of mammary glands, we determined the change not only in immunological function before and after electro-acupuncture in 44 in-patients with hyperplasia of mammary glands and having the same menstruation date, but also in electro-acupuncture treated rat hyperplasia of mammary glands model. We found that there was decrease of immunological function in hyperplasia of mammary glands and this function could be remarkably enhanced by electro-acupuncture both in hyperplasia of mammary glands patients and in rat hyperplasia of mammary glands model. The mechanism implies it might be that the inhibitory effect on immunological function exerted by high concentration of E2 was lowered by electro-acupuncture, hence the immunological function was reinforced. The results of this study are important in exploration of both the pathogenesis of this disease and the mechanism of electro-acupuncture, and in reducing the incidence of breast carcinoma.

Widespread expression of beta-defensin hBD-1 in human secretory glands and epithelial cells

We compared the expression of human alpha- and beta-defensins by various human tissues. mRNA for alpha-defensins HNP1-3, abundant in bone marrow, was detected in peripheral blood leukocytes, spleen and thymus by RT-PCR, which revealed alpha-defensins HD5 and HD6 only in the small intestine. In contrast, the pancreas and kidney expressed high levels of hBD-1 and lower levels of this beta-defensin were found in many organs by RT-PCR (salivary gland > trachea > prostate and placenta > thymus, testis, small intestine). hBD-1 mRNA was produced constitutively by cultured normal human epithelial cells derived from the trachea, bronchi, small airways and the mammary gland. These largely non-overlapping tissue distributions of human alpha- and beta-defensins suggest that hBD-1 may be positioned to defend epithelial cells and mucosae from infection, whereas expression of HNP1-3 in neutrophils and HD5 and HD6 in Paneth cells allows these alpha-defensins to participate in systemic and small intestinal host defenses, respectively.

[Microsurgical anatomical study of the wall of the cavernous sinus]

OBJECTIVE

To observe the microanatomical structures of the wall of cavernous sinus (CS) in order to provide anatomical basis for direct microsurgical operation to the CS.

METHODS

48 aides of the CS of adult cadavers were dissected in detail under operative microscope.

RESULTS

The CS was a narrow and long irregular hexahedron in shape. The supperior wall, the posterior wall and the superficial dural layer of the lateral wall of the CS were formed by internal layer of the cerebral dura. The deep layer of the interal wall was formed by the sheaths of nerves II, IV, V1, V2 with a reticular membrane between these sheaths. There was a superficial compartment between the superficial layer and deep layer of the lateral wall in 31.25% of the specimens. The inferior wall of the CS was intracranial periosteum. The medial wall was formed by stretched fibres from the tentorium of hypophysis. The anterior aspect was formed by the sphenoid sinus and the superior orbital fissure. Direct microsurgical approaches to the CS via the medial trangles of the superior wall and Parkinson tranales of the lateral wall were most important.

CONCLUSION

A microanatomical structure of the wall of the CS is provided for direct microsurgical operation to the CS, and the direct microsurgical approaches are discussed.

[The effect of implantation of reconstituted bone xenograft on the production of IL-2]

The present study is designed to investigate any possible effect of implantation of reconstituted bone xenograft (RBX) on the production of IL-2 by T-lymphocytes in female BALB/C mice model. IL-2 levels were elevated in all of the operated groups on the second day, suggesting a stress reaction to trauma caused by operative intervention rather than an immune response to RBX or bBMP. IL-2 production declined significantly on the 7th (P < 0.05) and 14th days (P < 0.01) in RBX and bBMP groups, an evidence of inhibiting effect of RBX on the T-lymphocyte function leading to lowered secretion of IL-2 by spleen T-cells in BALB/C mice. There was no significant difference in lowering of IL-2 secretion between the RBX and bBMP groups as seen when either was compared with the bCB group, suggesting an inhibiting action induced by BMP. The results demonstrated that RBX implantation was not associated with appreciable rejection in that activation, and proliferation of T-cells were inhibited and the secretion of cytokines was lowered resulting in suppressed cellular immunity. We are further convinced that RBX as an immuno-regulating cytokine possesses strong osteo-inductive potential without evoking rejection.

Novel azacyclic ureas that are potent inhibitors of HIV-1 protease

A series of novel, azacyclic ureas which are highly potent inhibitors of the HIV-1 protease (IC50 = 4.1 to < 0.5 nM) were synthesized. Aqueous solubilities of this series of compounds were improved by incorporating polar functional groups at the P1' P2 and P2' positions. These compounds also possess good anti-viral activity by inhibition of the cytopathic effect of HIV-13B in MT-4 cells in vitro.

Growth-independent induction of spermidine transport by IL-4 and IL-13 in ZR-75-1 human breast cancer cells

Polyamine transport is strongly induced by insulin and estradiol (E2) in ZR-75-1 human breast cancer cells. Because signal transduction mechanisms of insulin and interleukin-4 (IL-4) partly overlap, we have compared the ability of these agents as well as that of interleukin-13 (IL-13), a cytokine that often mimics IL-4, to modulate spermidine transport in these cells. In the presence of E2, insulin increased DNA content and the rate of [3H]spermidine uptake by 2.1- and 3.7-fold, respectively, after an 8-day incubation, whereas the sole addition of IL-4 caused a quantitatively similar induction of [3H]spermidine uptake while leaving cell growth unaffected. No comparable induction of spermidine transport was observed with interleukins-1 alpha and -6, and the effect of IL-4 was not additive to that elicited by insulin plus E2. IL-4 and IL-13 stimulated [3H]spermidine uptake to a comparable extent, with half-maximal effects observed at 80 and 400 pg/ml, respectively. Interferon-gamma inhibited IL-4- and IL-13-dependent spermidine uptake to a much greater extent than basal or insulin-induced transport of the polyamine. IL-4 and IL-13 increased the Vmax and K(m) of [3H]spermidine uptake by about 4- and 2.5-fold, respectively. Na(+)-dependent amino acid uptake was increased by insulin but not by IL-4 or IL-13, indicating that the cytokines do not induce a general increase in membrane transport activity. IL-4 and IL-13 did not interfere with feedback inhibition of polyamine uptake, and only modestly decreased polyamine content after prolonged incubation, suggesting that these cytokines stimulate spermidine uptake by increasing total transport capacity rather than by repressing and endogenous inhibitor.

Effect of prostatic growth factor, basic fibroblast growth factor, epidermal growth factor, and steroids on the proliferation of human fetal prostatic fibroblasts

To study the relationship between androgen metabolism and the pathogenesis of benign prostatic hypertrophy, we purified a growth factor from benign hyperplastic tissue of human prostates and assayed the proliferative responses of human fetal prostatic fibroblasts to the purified growth factor (hPGF), basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), dihydrotestosterone (DHT), and estradiol (E2). Prostatic tissue extracts were fractionated using heparin-Sepharose chromatography. The fraction that eluted with 1.3-1.7 M NaCl contained the majority of mitogenic activity. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS/PAGE) of the lyophilyzed active fraction showed a band at 17,000 daltons. Human prostatic fibroblasts were isolated from fetal prostate and tested for their proliferative responses to hPGF, bFGF, EGF, DHT, and E2. hPGF, as well as bFGF and EGF, did increase tritiated thymidine incorporation into the cultured fibroblasts. DHT(10(-7) M) had a significant stimulatory effect on cell growth in serum-free media after 6 days of culture. E2(10-7 M) had no effect on cell proliferation. The combination of DHT and E2 showed no synergistic effect. We conclude that our purified hPGF, bFGF, and EGF promote cell growth directly, DHT indirectly, while E2 does not. The effect of DHT appears to be mediated via the increased production and/or secretion of growth factor(s). Possibly, the bFGF-like hPGF purified from human benign hyperplastic prostatic tissue is such a mediator.

Inhibitory activity of the equine infectious anemia virus major 5' splice site in the absence of Rev

The major 5' splice site of equine infectious anemia virus (EIAV) conforms to the consensus 5' splice site in eight consecutive positions and is located immediately upstream of the gag AUG. Our results show that the presence of this 5' splice site on the EIAV gag mRNA decreases Gag production 30- to 60-fold. This is caused by inefficient nuclear mRNA export and inefficient mRNA utilization. Inhibition could be overcome by providing human immunodeficiency virus type 1 Rev/Rev-responsive element, human T-cell leukemia virus type 1 Rex/Rex-responsive element, or simian retrovirus type 1 constitutive transport element. In addition, inhibition could be abolished by introducing single point mutations in the 5' splice site or by moving the 5' splice site away from its natural position immediately upstream of the gag AUG. This demonstrates that both maintenance of a perfect consensus 5' splice site and its proper location on the mRNA are important for inhibitory activity of the EIAV major 5' splice site.

Identification of nuclear and cytoplasmic proteins that interact specifically with an AU-rich, cis-acting inhibitory sequence in the 3' untranslated region of human papillomavirus type 1 late mRNAs

Expression of human papillomavirus late genes encoding L1 and L2 capsid proteins is restricted to terminally differentiated epithelial cells. We have previously identified and characterized an AU-rich, cis-acting negative regulatory element in the 3' untranslated region of human papillomavirus type 1 late mRNAs. This element acts posttranscriptionally to reduce mRNA levels and the translation efficiency of mRNAs. The experiments reported here are a continuation of our previous work. We have used RNA gel shifts and UV cross-linking assays to identify cellular proteins that interact with the inhibitory RNA sequence of human papillomavirus type 1. RNA gel shift assays established that cellular proteins interact with the AU-rich sequence. The binding of nuclear proteins was inhibited by competition with poly(U), whereas the binding of cytoplasmic proteins was inhibited by competition with poly(U) and also by competition with poly(A) and poly(G). Two nuclear proteins and two cytoplasmic proteins that bind specifically to the AU-rich RNA sequence were identified by UV cross-linking. These proteins did not bind to the 3' untranslated region of human papillomavirus type 1 early mRNAs, which does not show inhibitory activity. The cellular proteins identified in our experiments may therefore be involved in the inhibition of human papillomavirus type 1 late gene expression in nondifferentiated epithelial cells.

Endotoxin and cytokines induce expression of leptin, the ob gene product, in hamsters

The expression of leptin, the ob gene product, is increased in adipose tissue in response to feeding and energy repletion, while leptin decreases food intake. Because adipose tissue gene expression is regulated by cytokines induced during infection and because infection is associated with anorexia, we tested whether induction of leptin might occur during the host response to infection. Administration of endotoxin (LPS), a model for gram negative infections, induces profound anorexia and weight loss in hamsters. In fasted adipose tissue to levels similar to fed control animals. There is a strong inverse correlation between mRNA levels of leptin and subsequent food intake. TNF and IL-1, mediators of the host response to LPS, also induced anorexia and increased levels of leptin in mRNA in adipose tissue. As assessed by immuknoprecipitation and Western blotting, circulating leptin protein is regulated by LPS and cytokines in parallel to regulation of adipose tissue leptin mRNA. Induction of leptin during the host response to infection may contribute to the anorexia of infection.

[Involvement of the nerve fiber elements in the anterior pituitary in the regulation of ACTH secretion]

While peptidergic nerve fibers have been immunoreactively identified in the adenohypophysis of mammals, the function of these fibers in the regulation of hormone secretion remain unknown. The present work was undertaken to investigate possible modulating effects of these fibers on the secretion of ACTH in the anterior pituitary. Electrical field stimulation (EFS) was applied to excite the nerve terminals in anterior pituitary quarters of male rats under static incubation, and the ACTH level was determined by radioimmunoassay. It was found that the ACTH release from the anterior pituitary was significantly enhanced by EFS (30 mA, 0.5 ms and 10 Hz), which could be significantly decreased by adding TTX or veratridine into the incubation medium. However, TTX failed to inhibit AVP-induced ACTH secretion. Since the dispersed cultured anterior pituitary cells did not respond to the same EFS, it was suggested that there might exist dual modulatory mechanisms on the anterior pituitary hormone secretion.

[Study on cellular proliferation activity of placental site trophoblastic tumor]

OBJECTIVE

To study the relationship among the cellular proliferation activity, benign clinical process and pathologic characteristics of placental site trophoblastic tumor (PSTT).

METHODS

Paraffin-embedded blocks from ten patients with PSTT were reexamined by mitotic count, argyrophilic nucleolar organizer regions (AgNOR) staining and flow cytometric DNA analysis. Five cases of hydatidiform mole (HM) and 5 choriocarcinoma (CC) were chosen as controls.

RESULTS

Mean mitotic figures of PSTT were 1.3 (0-3) per 10 high power field, while those of HM and CC were 0.8 (0-2) and 2.2 (1-4) respectively. AgNOR number of PSTT was 2.70 +/- 0.55 per cell, while those of HM and CC were 1.96 +/- 0.38 and 4.50 +/- 0.73 respectively. Flow cytometric DNA content revealed that PSTT had DNA index (DI) of 1.10, S phase of 16.7% and proliferating index (PI) of 26.6%. Eight of 10 Cases were followed up, 7 are alive and 1 died of primary lung cancer.

CONCLUSION

PSTT has relative low cellular proliferation activity. The good clinical procedure and benign pathological feature of PSTT may be associated with its diploidy DNA and low cellular proliferation activity.

A novel, picomolar inhibitor of human immunodeficiency virus type 1 protease

The design, synthesis, and molecular modeling studies of a novel series of azacyclic ureas, which are inhibitors of human immunodeficiency virus type 1 (HIV-1) protease that incorporate different ligands for the S1', S2, and S2' substrate-binding sites of HIV-1 protease are described. The synthesis of this series is highly flexible in the sense that the P1', P2, and P2' residues of the inhibitors can be changed independently. Molecular modeling studies on the phenyl ring of the P2 and P2' ligand suggested incorporation of hydrogen-bonding donor/acceptor groups at the 3' and 4-positions of the phenyl ring should increase binding potency. This led to the discovery of compound 7f (A-98881), which possesses high potency in the HIV-1 protease inhibition assay and the in vitro MT-4 cell culture assay (Ki = approximately 5 pM and EC50 = 0.002 microM). This compares well with the symmetrical cyclic urea 1 pioneered at DuPont Merck.

[Treatment of cerebrospinal rhinorrhea under nasal endoscope with EC ear-head adhesive]

Five cases of cerebrospinal rhinorrhea in frontal, ethmoid or sphenoidal sinus were repaired under endoscope with ear-head adhesive with satisfactory results. The advantages of the method are as follows: (1) The sufferings of the patient are minor and intercranial complications are fewer: (2) The location and size of the fistula are clear under endoscope: (3) The success rate is higher due to the application of ear-head adhesive: (4) With the use of muscles and fasciae outside the nose, the bleeding in nasal cavity may be avoided: (5) The curettages of the mucosa around the fistula and dura mater is helpful to the adherence of ear-head adhesive with these tissues.

[Vestibular and auditory functions in Ménière's disease]

This paper is, aiming at understanding disturbances of and correllation between colchear and vestibular functions in Meniere's disease. Auditory and vestibular functions in 121 Meniere cases (70 males and 51 females, age ranging from 19 to 63 years), diagnosed according to the AAO-HNS criteria, were analysed. The results were as follows: 1)There was positive correlation between semicircular canal paresis and hearing impairment. 2) There was statistically significant positive correlation between hearing impairment and the -SP/AP ratio. 3) There was statistically significant correlation between hearing impairment and glycerin test result, the rate of positive result being higher in those with advanced hearing loss than in those with mild loss. 4) There was correlation between the rate of positive glycerin test result and audiogram configuration. The rate with rising audiogram pattern was higher than with that falling pattern (69.0% vs 33.3%). It was also found that ECochG was far more effective than glycerin test in diagnosing Meniere's disease. The physiologic basis and significance of ECochG and glycerin test in Meniere's disease were discussed.

[Effects of ACM sequential chemotherapy on ovarian function in trophoblastic tumors]

OBJECTIVE

To study the changes of ovarian function during and after ACM sequential chemotherapy on trophoblastic tumors.

METHODS

17 patients with trophoblastic tumors, received totally 48 cycles of ACM chemotherapy. Of these, 7 underwent hysterotomy and focal ectomy and ovarian biopsy. Changes of menstruation and BBT were observed. beta-hCG, E2, FSH and LH were assayed and histological and immunohistochemical studies in ovaries biopsied were made.

RESULTS

Amenorrhea and anovulatory BBT were predominant at the onset of chemotherapy and high level of beta-hCG. Following chemotherapy and decrease of beta-hCG, menstruation recovered with less amount and BBT transformed into ovulatory types with shorter luteal phase. The E2 level appeared to be lower and the FSH and LH level higher. The different kinds of follicles were decreased, but estrogen receptors unchanged. Follow-up showed that ovarian function of 12 of the 17 patients returned to normal in one year.

CONCLUSION

ACM chemotherapy suppresses ovarian function mildly and temporarily. Trophoblastic tumor also affects ovarian function. ACM chemotherapy seems to be suitable for young patients with trophoblastic tumors who desire child-bearing.

Erythropoietin-like activity in vivo of the fusion protein rhIL-6/IL-2 (CH925)

CH925 is a novel cytokine of a fusion protein interleukin-6 (IL-6)/IL-2 exhibiting erythropoietin (Epo)-like effects in vivo and ex vivo, in addition to its enhanced effects compared to IL-2 and IL-6 reported by us previously, which indicates its potential clinical use. Our present study was undertaken to determine the Epo-like activity of CH925 in vivo. The reticulocyte response was observed in transfusion-induced polycythemic mice by using flow cytometry with pyronin Y staining. On day 2 after injection of CH925, the average number of reticulocytes was 2.11% in the group given 250 micrograms/kg/d and 1.01% for 100 micrograms/kg/d. The mean fluorescence intensity (MFI) also significantly increased. Longitudinal studies of CH925 were performed on days 2, 4, and 10, and reticulocyte counts increased up to a peak on day 4. Activity of CH925 (100 micrograms/kg/d) corresponds to 1 U of standard rhEpo in our study.

Abnormally high platelet activity after discontinuation of acetylsalicylic acid treatment

Production of 12-L-hydroxy-5, 8, 10-heptadecatrienoic acid (12-HHT) from platelets and bleeding times were studied in 32 males during acetylsalicylic acid (ASA) treatment and 1 and 2 weeks after withdrawal. All patients (age 42-77 years) had ASA treatment because of angina pectoris. The metabolite 12-HHT is formed in the same amount as the proaggregatory and vasoactive metabolite thromboxane A2. Initially the daily ASA dose was 75 mg (n = 15), 160 mg (n = 12) or 250-300 mg (n = 5). In all patients, median 12-HHT level increased from 40 to 240g/750 x 10(6) platelets (P < 0.001) 1 week after withdrawal of ASA, and four patients had abnormally high values. Median bleeding time decreased from 312 to 268 s (P = 0.003) in the 75 mg group and from 315 to 235 s in the 160 mg group (P = 0.01). Two weeks after withdrawal of ASA, median 12-HHT was 390g/750 x 10(6) platelets and eight patients (25%) had abnormally high values. One patient still had a prolonged bleeding time. Wide interindividual variations were observed in all groups. Our results indicate that rapid withdrawal of ASA, may cause abnormally high 12-HHT levels reflecting increase of thromboxane A2 with possible hazardous effects in patients with cardiovascular disease.

Protective effects of calcium from nonfat dried milk against colon carcinogenesis in rats

A number of studies have demonstrated the protective effect of dietary calcium against risk for colon cancer. The objective of this experimental study was to test the efficacy of two sources of dietary calcium, elemental calcium in the form of CaCO3 and dairy calcium as nonfat dried milk (NFDM), in colon tumor inhibition. Male weanling F344 rats were fed six test diets containing low (LF, 5%) and high (HF, 20%) levels of corn oil and low (0.5%) and high (1.0%) levels of calcium supplemented as CaCO3 or NFDM in a 2 x 3 factorial design. Tumors were induced with two weekly injections of azoxymethane at 12 mg/kg body wt. After 27 weeks on the test diets, animals were necropsied for tumor analysis. There was no difference in tumor incidence for fat or calcium source main effects, but a significant interaction was seen between fat and calcium source, with the lowest tumor incidence seen in the HF/NFDM group. Calcium compartmentalization studies demonstrated no effects of calcium on serum calcium levels but increased urinary and fecal water calcium in the higher-calcium diets. Increased dietary calcium also decreased fecal bile acid concentrations, but there was no effect on fecal water bile acids. Intermediate biomarkers of colon carcinogenesis were not affected by the dietary treatments except for fat effects on carcinogen-induced nuclear aberrations. These results indicate that source of calcium is not critical but that total dietary context may affect efficacy of calcium against colon carcinogenesis.

Structures of genes for two cathelin-associated antimicrobial peptides: prophenin-2 and PR-39

We characterized genes for prophenin (PF)-2 and PR-39, two cathelin-associated antimicrobial peptides found in porcine leukocytes. Both contained 4 exons and 3 introns and were compact, contiguous and highly homologous. Exons I-III encoded most of their cathelin domains. Exon IV specified the final few cathelin residues, including its conserved C-terminal valine, followed by the mature PR-39 peptide or a PF-2 precursor. The highly conserved 5' flanking sequences of this gene family contained NF-kappa B, IL-6, GM-CSF and NF-1 binding motifs and the introns were unusually conserved. These data suggest that the panoply of porcine cathelin-associated antimicrobial peptides arose relatively recently via gene reduplications and exon shuffling, and that in vivo expression of cathelin-associated antimicrobial peptides may respond to mediators generated early during infection.

The effects of prostaglandins E2 and F2 alpha on porcine ciliary muscle cells in culture

The purpose of this work is to investigate the effect of prostaglandins (PGs) on the contraction of ciliary muscle cells. It has been proposed that PGs induce relaxation of ciliary muscle and facilitate uveoscleral outflow, and reduce intraocular pressure (IOP). The ocular response to PGs is complicated because the relative contributions of uveoscleral flow and the conventional outflow to lowering IOP and the type of PG receptors associated with ciliary muscle may vary depending on animal species. In order to obtain insights into prostaglandin receptors of ciliary muscle, ciliary muscle cells from porcine eye were grown in culture and characterized immunocytochemically with antibodies against smooth muscle-alpha-actin and PGE2 receptor subtypes. As in ciliary muscle tissues, positive immunostaining for alpha-actin and EP2 and EP3 subtypes was observed in cultured cells. Time-dependent contraction of cultured cells induced by 10(-4) M carbachol was recorded by taking sequential photographs and analyzed. Using this assay method, the effect of prostaglandins E2 and F2 alpha to inhibit the carbachol-induced contraction was studied. PGE2 showed potent inhibition of cell contraction; 10(-7) approximately 10(-8) M PGE2 inhibited 50% of full contraction in 15 min. PGF2 alpha at 10(-4) M neither caused cell contraction by itself nor blocked carbachol-induced contraction. The EP2 agonist 11-deoxy-16, 16-dimethyl PGE2 at 10(-4) M inhibited cell contraction but the EP3 agonist sulprostone had no effect. Dibutyryl cAMP at 3 x 10(-5) M inhibited contraction by 50%. In the presence of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX), less than 10(-7) M dibutyryl cAMP caused 50% inhibition. In support of the cAMP effect, the addition of 10(-4) M PGE2 to cultured cells in the presence of indomethacin and IBMX was shown to cause an 80% increase in intracellular cAMP concentration compared with the basal (i.e. unstimulated) level of cAMP. Stimulation of cells with 10(-4) M PGF2 alpha caused no increase in cellular cAMP. These results indicate that PGE2 receptor EP2 subtype, but not PGF2 alpha receptor, is involved in the inhibition (hence relaxation by inference) of carbachol-induced porcine ciliary muscle cell contraction. It awaits further studies to determine whether cultured ciliary muscle cells of other species respond similarly to different PGs.

The role of recombinant human fusion protein IL-6/IL-2 (CH925) in hepadna virus infection treatment

The effects of CH925, a novel immune modulator, on hepadna virus infection was evaluated. Day-old ducklings were inoculated intravenously with LJ-76 DHBV containing serum. Infected ducklings were then treated with the CH925 and the mixture of IL-2 and IL-6 intravenously and the control ducklings received equivalent normal saline (NS). Blood and liver samples were taken and assayed for DHBV DNA and/or DHBsAg. At the completion of the experiment there was a inhibition of viremia with the CH925 and IL-2 + IL-6. Serum DHBV DNA was detected in 6 of 10 ducks in 100,000 unit/kg dosage group, 7 of 10 ducks in 50,000 unit/kg dosage group and 6 of 10 ducks in IL-2 + IL-6 dosage group, compared with 9 of 10 NS control, and it showed a similar result in circulating DHBsAg. When samples of liver DNA were processed for hybridization, a little difference in the DHBV DNA replication was noted between ducks receiving CH925, IL-2 + IL-6 or NS placebo. It is suggested that CH925 might be a potential remedy in HBV infection treatment.

Cloning, expression and purification of the ligand-binding region of human IL-6R in E. coli and its preliminary functional identification

The ligand-binding region of human IL-6R is taken as the target gene fragment to be cloned and expressed. With pET-3b as expressing vector, two recombinants pET-6R(B) and pET-6R(B)4 have been constructed encoding the ligand-binding region (28 kD) of hIL-6R and its dimmer (53 kD), respectively. After induction with IPTG, they produced two proteins rIL6R-28 of 28 kD and rIL6R-53 of 53 kD amounting to 50% and 30% of total bacteria proteins, respectively. The expressed products were mainly recovered as inclusion bodies. After purification and renaturation, both of them were capable of augmenting the growth-stimulating effect of IL-6 on 7TD1 cells, an IL-6 dependent cell line. The result of ELISA also revealed that both rIL6R-28 and rIL6R-53 had the obvious ligand-binding activity.

Expression of human interleukin-11 cDNA in E. coli

A 551-bp hIL-11 gene fragment that includes no nucleotide sequences encoding signal polypeptide and the initial 8 amino acids of the mature protein was cloned into a high-level expression vector pEx31B of E. coli. The authors identified the recombinant plasmid, designated pEx31-IL11, by restriction endonucleases digestion and DNA sequencing. The resulting recombinant plasmids were then used to transform E. coli strain HB101, and expression in the PL promoter system, which is temperature-regulated, was achieved. The expressed fusion protein amounts to 50% of total bacterial proteins. The hIL-11 protein expressed in E. coli was fused to the N-terminal 99 amino acids of the MS2 polymerase to form the inclusion body. These recombinant proteins can be purified to about 80% by extracting inclusion body with urea. One IL-6-dependent cell line 7 TD1 was used for bioassay. The recombinant hIL-11 protein was preliminarily purified and renatured to a specific activity of 10(5)U/mg, even in the presence of an excess of a neutralizing anti-IL-6 antibody.

Histocytological study on the possible mechanism of acetaminophen cataractogenesis in mouse eye

Ocular toxicity of acetaminophen was investigated in cytochrome P450 inducer-responsive and nonresponsive strains of mice by light and electron microscopy. Acetaminophen injected into C57BL6 mice (responsive strain) that had been pretreated with beta-naphthoflavone produced cataract. The drug did not induce cataract in C57BL6 mice without the pretreatment or in DBA2 mice (nonresponsive strain) similarly pretreated with beta-naphthoflavone. Therefore, induction of cytochrome P450 enzymes that metabolically activate acetaminophen is essential for cataractogenesis. Following acetaminophen injection, tissue damage became noticeable first in the ciliary epithelium and then spread to the iris, corneal endothelium, and lens. The neural retina, retinal pigmented epithelium, and choroid remained unaffected. A close examination of tissues revealed that mitochondria are the primary target of acetaminophen cytotoxicity in ocular tissues affected. The nucleus, endoplasmic reticulum, and other subcellular structures appeared normal. The course of propagation of tissue damage and the almost exclusive damage to mitochondria suggest that the cytotoxic metabolite of acetaminophen is secreted with the aqueous humor by the ciliary epithelium and transported to the lens and that inhibition of mitochondrial energy metabolism, together with other effects of the metabolite, contributes to acetaminophen-induced cataract.

An immunocytochemical study on relations between mast cell and peptidergic terminals in nasal mucosa of chronic rhinitis patients

Mast cell-nerve relation is a new topic explored deeply in different organs, but little documentation could be found in the literature on the relation in human nasal mucosa. We carried out this study using immunocytochemistry and found that substance P (SP) terminals were present in human nasal mucosa from six cases of chronic rhinitis. SP terminals were often found to be adjacent to or have a direct contact with mast cells (MCs). Electron-microscopic studies revealed that MCs could contact nonmyelinated nerve terminals. These results have important implications in the understanding of the pathogenesis of neurogenic inflammation seen in nasal mucosa and will probably cast new insight into the future treatment of such disease.

The structure of porcine protegrin genes

We cloned the genes of three protegrins, a family of cathelin-associated antimicrobial peptides originally isolated from porcine leukocytes. Each gene comprised 4 exons and 3 introns, wherein Exon I encoded the signal sequence and the first 37 amino acids of cathelin, Exons II and III contained 36 and 24 additional cathelin residues and Exon IV contained the final two cathelin residues followed by the protegrin sequence. This quadripartite gene structure helps explain how structurally diverse antimicrobial peptides can be expressed on common, cathelin-containing precursors. Southern blot probed with an oligonucleotide specific for protegrin genes suggested that several identical or nearly identical protegrin genes were densely clustered in the pig chromosome.

Potent inhibitors of the HIV-1 protease with good oral bioavailabilities

A series of novel pseudo-symmetrical and unsymmetrical inhibitors based on the backbone modification of a peptidomimetic were synthesized and found to be highly potent inhibitors of the HIV-1 protease (IC50 = 2.9 to < 0.5 nM). These compounds also possess good antiviral activity in vitro as measured by inhibition of the cytopathic effect of HIV-1(3B) in MT-4 lymphocytes. Importantly, some of these compounds also have good oral bioavailabilities in rats (F = 30.6% to 100%). One of these compounds 4C, also has good oral bioavailability in beagle dogs and cynomolgus monkeys.

Electric acupuncture treatment of peripheral nerve injury

54 cases of peripheral nerve injury were treated by electric acupuncture and compared with 54 control cases treated with supportive medication. The changes after treatment were observed chiefly by electromyography while sensory and motor improvement were also recorded as auxiliary indicators. The therapeutic results in the acupuncture group were 5 cases cured, 26 markedly effective, 19 improved, and 4 cases failed, a total effective rate of 92.6% in contrast to the 55.6% for the controls. Analysis of the therapeutic results showed that 1) those in the acupuncture group were significantly better than in the control group; 2) nerve injuries should be treated as early as possible; 3) the radial nerve and the common peroneal nerve recovered faster than others; 4) cases not surgically explored recovered faster than those that were, and 5) patients with prompt propagation of the needling sensation recovered significantly faster than those with slow propagation.

[Management of the dry eye with parotid duct transplantation: a summary on 40 cases]

PURPOSE

As today the effect of parotid duct transplantation is clinically regarded as uncertainty, and there is still absent of effective managenent of the dry eye, this paper tries to clarify its value, and see if it can be used clinically.

METHODS

Forty dry eyes were operated with a follow up of 3 weeks to more than 6 years in the past 42 years. The pre- and postoperative changes of tear flow and vision, and the cause of dry eye, operative method, length of parotid duct and complications of bilateral operation were briefly summarized.

RESULTS

Of these 40 operated eyes postoperatively, 82.5% had tearing, but no tearing occurred in 27.5%. Finally: vision increased in 72.5% with out any decrease. There was no difference in the results whether the procedure done extraorally or intraorally. The parotid duct being shorter was only seen in 7.5%, which were satisfactorily managed by tube making with oral mucosa. Four cases operated binocularly and silmutaneously, only 1 occurred aveolar abscess with complaining dry mouth, but cured 1 week later. After operation, profusive tearing occurred in 25 dry eyes caused by trachoma during eating and 96% usually, but tearing stopped finally in 3 eyes (2, due to infection). Four dry eyes with ocular pemphigoid failed. Among 9 dry eyes resulted from Stevens-Johnson syndrome, 6 had little tearing postoperatively, 2 of which attained a nearly normal results. One of the two dry eyes resulted from alkali eye burn failed and the other, occurred tearing but only followed-up for 1 month, the result was uncertain.

CONCLUSION

As the technique of the parotid duct transplantation is simple and easy with no much complications, and for treating the dry eye, there is up to now still absent of effective management, therefore, the parotid duct transplantation should be considered to be indicated in dry eyes esp, caused by Stevens-Johnson syndrome. Though its success rate is lower than that of traucomatous ones, the satisfactory result of nearly normal postoperative tearing may be got. In ocular pemphigoid, however, it is contraindicated.

[False dysphagia caused by omohyoid muscle syndrome: 50 cases of autopsy and 2 cases of clinical reports]

Omohyoid muscle syndrome is rarely seen clinically. A mass can be seen on the neck while swallowing, and the patient feels discomfort and dysphagia. The mass disappears immediately after swallowing and you can't find the mass by palpation. We made autopsies in 50 cases of omohyoid muscle syndrome, and observed muscles, especially the intermediate tendons, sheaths of tendon and projection of omohyoid muscles. The restriction and regulatory functions of intermediate tendon sheaths during contraction of the omohyoid muscles were briefly explained. By combination with 2 cases of clinical reports, also investigated. We also investigated the etiology of omohyoid muscle syndrome.

Non-promoting effects of lean beef in the rat colon carcinogenesis model

Recent epidemiologic studies have implicated red meat consumption as a risk factor for colon cancer in both men and women. However, it has been very difficult to separate the effects of meat as a protein source from the accompanying fat content of the diets analyzed in these studies. Experimental data from rodent feeding trials show mixed results, with no firm conclusions being possible in terms of the colon-cancer promoting effects of meat fat. The goal of the present study was to compare, in an experimental animal model, the effects of beef with casein as a protein source, within the context of a low- and high-fat diet containing either corn oil or beef tallow, on promotion of colon carcinogenesis. Tumors were induced in Sprague-Dawley rats with 1,2-dimethylhydrazine (20 mg/kg body wt for 10 weeks). Two hundred and eighty male weanling rats were randomized to eight dietary treatment groups of a 2x2x2 factorial design with fat source (corn oil vs. beef tallow), fat level (5% vs. 20%), and protein source (very lean beef vs. casein) as the factors. Diets were fed ad libitum before, during and after carcinogen treatment for a total of 27 weeks. At termination of the study, animals were examined for location, size and type of colon or extracolonic lesions. The total incidence and number of colon tumors were significantly lower in the groups fed beef rather than casein. High fat levels, regardless of source, significantly increased the number of colon adenomas. These results demonstrate that when lean beef is used as the protein source in the context of a low-fat diet, fewer intestinal tumors develop. These data do not support the belief that red meat consumption increases the risk for colon carcinogenesis, but underscores the importance of fat level in dietary context.

[Isolation and identification of Rhodopseudomonas viridis and Rhodopseudomonas sulfoviridis]

Under selective culture conditions, two pure cultures (strain G and strain SG) of the purple nonsulfur photosynthetic bacteria containing bacteriochlorophyll b were isolated from pulp effluent and sludge of sewage treatment plant by means of agar shake dilution. Although the cells of strain G and strain SG contained bacteriochlorophyll b and carotenoids, intra-cytoplasmic membranes were of lamellar type parallel to cytoplasmic membrane, the two strains differ in using various organic carbon sources, depending on reduced sulfur compounds and assimilate sulfate. According to Bergey's Manual of Systematic Bacteriology Volume 3, strain G was identified to be Rhodopseudomonas viridis,, strain SG was identified to be Rhodopseudomonas sulfoviridis.

Chemopreventive effects of calcium but not aspirin supplementation in cholic acid-promoted colon carcinogenesis: correlation with intermediate endpoints

Epidemiological studies have suggested that increased intake of calcium (Ca) or aspirin (ASA) is associated with a reduced risk for colon cancer. To delineate a possible mechanism of action, the present study used male F344 rats in an azoxymethane (AOM)-induced colon tumor model to study the single and interactive effects of Ca and ASA on cholic acid-promoted experimental colon carcinogenesis. Following initiation with AOM, a promotion diet containing 0.5% cholic acid was fed for 34 weeks until the adenoma development stage. Cholic acid was used as a surrogate for high-fat diets and to promote carcinogenesis. Diets were supplemented with CaCO3 (2% Ca by weight), 250 p.p.m. ASA, or both. After 34 weeks, the diets were switched during the progression stage and rats were killed at week 51. Several intermediate endpoints were examined during the course of AOM carcinogenesis to determine their reliability as predictors of colon cancer risk. Intermediate endpoints included colon crypt height measurement, colon mucosal ornithine decarboxylase (ODC) and colon mucosal protein kinase C (PKC) activities. The biomarkers were examined at the beginning of the study at 2 weeks, and thereafter at 5, 15, 30 and 40 weeks of dietary treatment. Animals were necropsied at week 51 and tumor incidence and numbers were analyzed for correlation with biomarkers. Survival was highest in the group fed CaCO3 during the promotion stage and tumor burden was lowest in groups fed CaCO3 during this stage. Supplementation during the progression stage was ineffective. The cholic acid promotion model resulted in increased ODC which was inhibited by intervention during the promotion stage with Ca, but not ASA. PKC was also activated by cholic acid feeding, and this effect was modulated by intervention in the promotional stage with Ca or ASA. Colon tumor incidence and burden was increased by cholic acid promotion and decreased by Ca, but not affected by ASA. In summary, Ca is a more effective chemopreventive agent in cholic acid-promoted colon carcinogenesis than ASA, impacting both incidence and tumor number. Colonic ODC, but not PKC may be a suitable predictor of risk and response in chemoprevention trials for colon cancer.

Prophenin-1, an exceptionally proline-rich antimicrobial peptide from porcine leukocytes

We purified and characterized an unusual antimicrobial peptide, prophenin-1 (PF-1), from porcine leukocytes. The peptide had a mass of 8,683 and contained 79 residues, including 42 (53.2%) prolines and 15 (19.0%) phenylalanines. Its N-terminal 60 residues consisted of three perfect and three nearly perfect repeats of a decamer, FPPPNFPGPR. Prophenin-1 was encoded on a cathelin-containing precursor and showed substantially more activity against E. coli, a Gram-negative bacterium, than against Listeria monocytogenes, a Gram-positive organism, in vitro.

Immunocytochemical study of cytochrome P450 (1A1/1A2) induction in murine ocular tissues

C57BL/6 and DBA/2 mice were injected intraperitoneally with beta-naphthoflavone in corn oil and killed 48 hr later. Control animals received an injection of corn oil. The immunoreactivity of cytochrome P450 1A1/1A2 expressed in different ocular tissues and liver was examined with goat anti-P450 antibody (primary antibody) and gold-conjugated anti-goat antibody (secondary antibody). DBA/2 mice, which are non-responsive to aryl hydrocarbon treatment, showed negligible levels of immunoreactivity toward anti-P450 1A1/1A2 antibody in all ocular tissues, whether or not the animals were treated with beta-naphthoflavone. In responsive C57BL/6 mice, however, the immunoreactivity of the uveal tissues, especially ciliary non-pigmented epithelium, was markedly increased by beta-naphthoflavone treatment. The time course of induction of P450 1A1/1A2 immunoreactivity was very similar for the liver and ciliary non-pigmented epithelium, although the maximum level of immunoreactivity of the ciliary epithelium reached in 48 hr after inducer treatment was about 25% of that of liver. The present results support our previous observations that the P4501A enzyme activities (e.g. aryl hydrocarbon hydroxylase) in the liver and eye of C57BL/6 mice are under the same genetic regulation. Further, this study is the first demonstration of P450 isoform induction in specific ocular tissues of the whole animal.

Inorganic cation dependence of putrescine and spermidine transport in human breast cancer cells

The mechanism of polyamine uptake in mammalian cells is still poorly understood. The role of inorganic cations in polyamine transport was investigated in ZR-75-1 human breast cancer cells. Although strongly temperature dependent, neither putrescine nor spermidine uptake was mediated by a Na+ cotransport mechanism. In fact, Na+ and cholinium competitively inhibited putrescine uptake relative to that measured in a sucrose-based medium. On the other hand, ouabain, H+, Na+, and Ca2+ ionophores, as well as dissipation of the K+ diffusion potential, strongly inhibited polyamine uptake in keeping with a major role of membrane potential in that process. Polyamine transport was inversely dependent on ambient osmolality at near physiological values. Putrescine transport was inhibited by 70% by decreasing extracellular pH from 7.2 to 6.2, whereas spermidine uptake had a more acidic optimum. Deletion of extracellular Ca2+ inhibited putrescine uptake more strongly than chelation of intracellular Ca2+. In fact, bound divalent cations were absolutely required for polyamine transport, as shown after brief chelation of the cell monolayers with EDTA. Either Mn2+, Ca2+, or Mg2+ sustained putrescine uptake activity with high potency (Km = 50-300 microM). Mn2+ was a much stronger activator of spermidine than putrescine uptake, suggesting a specific role for this metal in polyamine transport. Other transition metals (Co2+, Ni2+, Cu2+, and Zn2+) were mixed activators/antagonists of carrier activity, while Sr2+ and Ba2+ were very weak agonists, while not interfering with Ca2+/Mg(2+)-dependent transport. Thus, polyamine uptake in human breast tumor cells is negatively affected by ionic strength and osmolality, and is driven, at least in part, by the membrane potential, but not by the Na+ electrochemical gradient. Moreover, the polyamine carrier, or a tightly coupled accessory component, appears to have a high-affinity binding site for divalent cations, which is essential for the uptake mechanism.