The role of Kupffer cells in the surveillance of tumor growth in the liver

The present study was designed to investigate the role of Kupffer cells (Kc) in the surveillance of liver tumors. We examined the antitumor activity of Kc by 51Cr releasing assay and inhibition of [3H]thymidine ([3H]TdR) incorporation into tumor cells. We also studied the change in the growth of liver tumors following the activation and the blockade of Kc. The cytotoxicity of Kc against K562 increased as the effector:target (E:T) ratio rose and reached its maximum level of about 18% at an E:T ratio of 20:1. [3H]TdR incorporation into target cells (P815 and AH130) was also inhibited by Kc. Such antitumor activity of Kc was augmented by OK432 (K562, from 13.8 +/- 5.6 to 21.9 +/- 2.5%; AH130, from 19.2 +/- 14.5 to 37.1 +/- 12.6%). In the experiment of the inoculation of AH130 via the portal vein, OK432 decreased the number of hepatic foci, whereas macrophage inhibitors carrageenan and gadolinium increased the number of tumor nodules. In addition, gadolinium injection reduced the number of Kupffer cells reactive with monoclonal antibodies directed against macrophages ED2 and Ki-M2R. Tumor growth in the liver was maximum in rats with both gadolinium treatment and splenectomy. In conclusion, Kc have antitumor activity, and augmentation of Kc may be a possible strategy to prevent hematogenous hepatic metastasis.

Amino acid sequences of ovomucoid third domains from 27 additional species of birds

Ovomucoids consist of a single polypeptide chain which is composed of three tandem Kazal domains. Each Kazal domain is an actual or putative protein inhibitor of serine proteinases. Ovomucoid third domains were already isolated and sequenced from 126 species of birds (Laskowski et al., 1987, 1990). This paper adds 27 new species. A number of generalizations are made on the basis of sequences from 153 species. The residues that are in contact with the enzyme in enzyme-inhibitor complexes are strikingly hypervariable. While the primary specificity residue, P1, is the most variable; substitutions occur predominantly among aliphatic, hydrophobic residues. Consensus sequences for an avian ovomucoid third domain, for a b-type Kazal domain (i.e., a COOH terminal domain of multidomain inhibitors) and for a general Kazal domain are given. Finally, the individual new sequences are briefly discussed.

Histochemistry with Helix pomatia agglutinin in human germ cell tumors: detection of nongerminomatous components and correlation between HPA reactivity and radiosensitivity in germinomas

Binding sites of Helix pomatia agglutinin (HPA) were examined in 32 patients with intracranial human germ cell tumors. HPA reactivity was found in vascular endothelial cells and erythrocytes of patients with blood type A or AB. HPA-positive neoplastic cells were seen in one yolk sac carcinoma in a patient with blood group A, and in embryonal carcinomas and teratomas irrespective of blood group type. Although in 10 out of 18 germinomas neoplastic cells were totally negative for HPA, another 8 germinomas showed HPA-positive neoplastic cells which were distributed sporadically or in an area and independent of blood group types. HPA-negative germinoma patients showed a very good response to radiotherapy, whereas 4 out of 8 HPA-positive tumors showed poor radiosensitivity, with a residual lesion seen on computed tomography even after the total radiation dose of 40-50 Gy. These findings suggest that HPA-positive neoplastic cells in germinomas indicate components of differentiation of non-germinomatous germ cells. HPA-positive germinomas might be less radiosensitive than HPA-negative germinomas.

Arg15-Lys17-Arg18 turkey ovomucoid third domain inhibits human furin

Turkey ovomucoid third domain with Leu18 in its reactive site is a potent inhibitor of many serine proteinases: subtilisins, chymotrypsins, and elastases. Previous studies showed that an L18K mutation made it a moderately strong inhibitor of trypsin, while an L18E mutation made it a strong inhibitor of Glu-specific Streptomyces griseus proteinase (GluSGP). For human furin substrates the consensus optimal sequence is RXKR decreases. Therefore the A15R, T17K, and L18R mutations were made in turkey ovomucoid third domain. The mutant inhibits human furin with a Ka of 1.1 x 10(7) M-1. As human furin catalyzes an obligatory step in human immunodeficiency virus proliferation, this inhibitor, along with the others already available, deserves further study.

Mechanism of the preserving effect of aprotinin on platelet function and its use in cardiac surgery

The deficiency of platelet function is the main defect of the hemostatic mechanism during cardiopulmonary bypass, which greatly exacerbates the postoperative bleeding complications. In this study, we assessed, from basic and clinical perspectives, the mechanism of relieving platelet damage by means of aprotinin. In vitro research confirmed that the addition of urokinase (40 U/ml) to platelet-rich plasma and the addition of plasmin (0.3 U/ml) to washed platelets made ristocetin-induced agglutination decline to 31.6% and 38.5% of control values, respectively. The extent of decline was positively correlated with the concentration of urokinase and plasmin. In addition, the platelet membrane glycoprotein Ib decreased to 76.4% of control value. With the addition of urokinase or plasmin to aprotinin-pretreated platelet-rich plasma or washed platelets, the changes in agglutination are not statistically significant and the decrement in glycoprotein Ib is much less marked. Further in vivo research revealed that cardiopulmonary bypass caused a decrease in plasma alpha 2-antiplasmin, indicating the fibrinolytic system activation. Meanwhile, ristocetin-induced agglutination decreased to 39.6% and platelet glycoprotein Ib decreased to 50% of preoperative values. However, with the administration of aprotinin, plasma alpha 2-antiplasmin during cardiopulmonary bypass did not change; platelet agglutination was improved, platelet glycoprotein Ib was preserved, and this consequently resulted in 46% lower blood loss after the operation. The results showed that fibrinolysis impaired platelet function, and this effect may be associated with the hydrolysis of glycoprotein Ib. Fibrinolytic activation occurred during cardiopulmonary bypass and contributed to postoperative platelet dysfunction to a great extent. Aprotinin may inhibit fibrinolysis during cardiopulmonary bypass and thus relieve the platelet damage and improve the postoperative hemostatic mechanism.

Effects of interleukin-1 alpha on arachidonic acid metabolism in human osteosarcoma osteoblastic cells

The effects of interleukin-1 alpha (IL-1 alpha) on arachidonic acid (AA) metabolism were studied in the human osteosarcoma cell lines, G292 and SaOS-2. The cells were prelabeled with 3H-arachidonic acid. Radiolabeled metabolites were measured by reversed-phase high-pressure liquid chromatography with a radioactive detector. Indomethacin inhibited prostaglandin E2 (PGE2) production without affecting lipoxygenase (LO) products in G292 cells. In the G292 cells, IL-1 alpha (50 U/ml) induced a 10-fold increase in PGE2 production at all the incubation times tested, and a significant two-fold increase in 5 hydroxyeicosatetraenoic acid (HETE) formation after 48 h. These effects were not seen in SaOS-2 cells under identical conditions. These results suggest that, although some osteosarcomal cell lines may not respond directly to IL-1 with effects on AA metabolism, the mechanism of its action in others may involve modulation of both cyclooxygenase (CO) and LO pathways.

Mechanisms of multisite phosphorylation and inactivation of rabbit muscle glycogen synthase

Glycogen synthase, a rate-determining enzyme for glycogen biosynthesis, is regulated by complex multisite phosphorylation of its subunit. Previous work has suggested that phosphorylation by some protein kinases, casein kinase II and cyclic AMP-dependent protein kinase, potentiates the ability of other protein kinases, glycogen synthase kinase 3 and casein kinase I, respectively, to modify the enzyme. In the present study, active glycogen synthase was expressed in Escherichia coli using a pET vector. The purified recombinant glycogen synthase had specific activity and subunit M(r) similar to enzyme isolated from rabbit muscle. Prior phosphorylation by casein kinase II was found to be an obligate requirement for phosphorylation by glycogen synthase kinase 3, which introduced 4 mol phosphate/mol subunit. Casein kinase II action did not affect activity, whereas the phosphorylation catalyzed by glycogen synthase kinase 3 caused a potent inactivation, reducing the +/- glucose 6-phosphate activity ratio from 0.7 to 0.10. Casein kinase I alone phosphorylated the recombinant glycogen synthase, indicating that substrate phosphorylation was not an absolute requirement. However, the prior action of cyclic AMP-dependent protein kinase significantly potentiated the ability of casein kinase I to phosphorylate and inactivate glycogen synthase. All previous analyses of glycogen synthase phosphorylation have used enzyme purified from mammalian sources and containing residual covalent phosphate. By using recombinant substrate, the present study represents a rigorous assessment of the role of prior phosphorylation in the recognition of mammalian glycogen synthase by glycogen synthase kinase 3 and casein kinase I. The conclusion is that phosphorylation of glycogen synthase can involve the concerted action of multiple protein kinases.

Synthetic and computer-assisted analysis of the structural requirements for selective, high-affinity ligand binding to diazepam-insensitive benzodiazepine receptors

Several 1,4-diazepines were recently reported to bind with high affinities to the "diazepam-insensitive" (DI) isoform of the benzodiazepine receptor (BzR) (Korpi, E.R.; Uusi-Oukari, M.; Wegelius, K. Eur. J. Pharm. 1992, 213, 323-329. Wong, G.; Skolnick, P. Eur. J. Pharmacol. Mol. Pharm. Sec. 1992, 225, 63-68). However, only the putative ethanol antagonist 1 (Ro 15-4513) displayed modest selectivity for the DI site compared to other "diazepam-sensitive" (DS) BzR isoforms. In order to probe the requirements for selective, high-affinity binding to the DI site, the affinities of 47 benzodiazepines have been determined at both DI and DS BzR sites. In addition, single X-ray crystallographic analyses for three of these derivatives, 5 (Ro 17-1812), 6 (Ro 16-6028), and 42 (Ro 14-5974), are reported. The radioligand binding studies reveal that modifications to the 3-, 7-, and 8-positions of 6-oxoimidazo[1,5-alpha] [1,4]benzodiazepines have a marked influence on the Ki(DI)/Ki(DS) ratios. In order to more precisely determine the structural requirements for both high affinity and selectivity at DI BzR relative to DS, 3D-QSAR analyses were carried out on ligand affinities at both of these BzR isoforms. This analysis was based, in part, on the new X-ray crystallographic data. Satisfactory cross-validated regression equations were obtained individually for the logarithms of ligand affinities at DI and DS as well as for the differences of the logarithms of their affinities at these two isoforms (cross-validated R2 > 0.70 for all three regression equations). The steric and electrostatic 3D-QSAR DI and DS maps are in qualitative accord with the structure-activity relationship (SAR) data. Furthermore, the DI and DI/DS maps may be useful in the design of ligands with enhanced DI affinity and DI/DS selectivity, respectively.

Relationship between Ricinus communis agglutinin-1 binding and nucleolar organizer regions in human gliomas

Histochemical staining using lectins from Ricinus communis (RCA-1), Arachis hypogaea, and Canavalia ensiformis was investigated in 40 human gliomas, three central neurocytomas, one human neuroblastoma cell line (IMR-32), and two normal brain tissues. Staining was uniform in low-grade gliomas, but heterogeneous in high-grade gliomas, particularly with RCA-1. The correlation between RCA-1 reactivity and cellular proliferative potential was investigated in 10 high-grade gliomas using a combined staining technique: the silver colloid method for nucleolar organizer regions (Ag-NORs) and histochemistry with RCA-1. The mean number of Ag-NORs counted on a simple preparation was significantly greater in the nuclei of RCA-1-negative cells than in those of RCA-1-positive cells (p < 0.001). The staining intensity of inflammatory cells was obviously higher than that of neoplastic cells, and therefore inflammatory cells were easily discriminated from neoplastic cells. Combined RCA-1 histochemical and Ag-NOR silver colloid staining revealed heterogeneous expression of RCA-1 receptor in high-grade gliomas with changes in Ag-NOR number. This result seems to show that high-grade gliomas express heterogeneous cellular carbohydrate structure and proliferative potential even within the same tumor.

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency: diagnosis by acylcarnitine analysis in blood

Medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency is a disorder of fatty acid catabolism, with autosomal recessive inheritance. The disease is characterized by episodic illness associated with potentially fatal hypoglycemia and has a relatively high frequency. A rapid and reliable method for the diagnosis of MCAD deficiency is highly desirable. Analysis of specific acylcarnitines was performed by isotope-dilution tandem mass spectrometry on plasma or whole blood samples from 62 patients with MCAD deficiency. Acylcarnitines were also analyzed in 42 unaffected relatives of patients with MCAD deficiency and in other groups of patients having elevated plasma C8 acylcarnitine, consisting of 32 receiving valproic acid, 9 receiving medium-chain triglyceride supplement, 4 having multiple acyl-coenzyme A dehydrogenase deficiency, and 8 others with various etiologies. Criteria for the unequivocal diagnosis of MCAD deficiency by acylcarnitine analysis are an elevated C8-acylcarnitine concentration (> 0.3 microM), a ratio of C8/C10 acylcarnitines of > 5, and lack of elevated species of chain length > C10. These criteria were not influenced by clinical state, carnitine treatment, or underlying genetic mutation, and no false-positive or false-negative results were obtained. The same criteria were also successfully applied to profiles from neonatal blood spots retrieved from the original Guthrie cards of eight patients. Diagnosis of MCAD deficiency can therefore be made reliably through the analysis of acylcarnitines in blood, including presymptomatic neonatal recognition. Tandem mass spectrometry is a convenient method for fast and accurate determination of all relevant acylcarnitine species.

Simulation of marker-assisted selection utilizing linkage disequilibrium: the effects of several additional factors

Use was made of our published model and methods to investigate the effects of several additional factors on marker-assisted selection (MAS) utilizing linkage disequilibrium. The additional factors were: size of the sample used to estimate the marker quantitative trait locus (MQTL) association effects, the method used to estimate the MQTL effects, use of the average of the top MQTL estimates in selection rather than individual estimates, size of the selection population, and the crossing of duplicate selection lines to generate further linkage disequilibrium and further selection response. The average map distance between the quantitative trait loci (QTLs) and their nearest marker was 0.15 Morgans. Use of estimates of MQTL effects derived by least squares yielded smaller selection responses than estimates derived by mixed-model methods. Selection responses were also reduced by using a smaller sample for estimating the associations because MQTL effects were less well estimated. This applied to selection on the MQTL effects themselves and to selection combining the MQTL with phenotypic information. Thus, poorly estimated MQTL effects added noise to the system and reduced selection response in combined selection. Using the average of the top MQTL estimates, rather than individual estimates, also reduced selection response. New linkage disequilibrium, generated by crossing two lines selected from the same population, did not lead to additional selection response in the cross line. These results show limitations to MAS using linkage disequilibrium until close linkages of markers and QTLs are available.

Effect of interferon-gamma on ACNU-induced DNA damage and cytotoxicity in human glioblastoma cells

Interferons (IFNs) are a natural body defense with powerful effects on tumor growth, including gliomas. The direct effects of IFN-gamma on (1-4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU)-induced deoxyribonucleic acid (DNA) damage and cytotoxicity were investigated in two human glioblastoma cell lines, A-172 and T98G, using a single cell microgel electrophoresis technique and a microculture tetrazolium assay. The results demonstrated a synergistic effect of IFN-gamma with ACNU on intracellular damage in both cell lines. 10 micrograms/ml ACNU induced a cell inhibition rate of 23.9% in A-172 cells, and almost no effect on T98G cells. 1000 U/ml IFN-gamma and 10 micrograms/ml ACNU caused a significant increase in cell inhibition, 51.2% for A-172 and 72.3% for T98G cells. DNA damage in individual A-172 and T98G cells exposed to ACNU was enhanced significantly by IFN-gamma (p < 0.001). The findings suggest a direct effect of IFN-gamma on ACNU-induced cell damage in human glioma, in addition to its effect on immunomodulation.

Modulation of the intracellular Ca2+ and inositol trisphosphate concentrations in murine T lymphocytes by the glycosylphosphatidylinositol-anchored protein sgp-60

Stimulation of T lymphocytes via the TCR/CD3 complex initiates a series of intracellular biochemical events. Among the earliest cellular responses are the stimulation of the turnover of phosphatidylinositol and an increase in the intracellular Ca2+ concentration. The significance of these second messengers for distal cellular responses such as lymphokine production or cell proliferation is not understood. We have previously shown that hamster mAb to the murine glycosylphosphatidylinositol-anchored protein sgp-60 can inhibit IL-2 production, IL-2R expression, and cell proliferation, events normally observed after stimulation of T cells with an antibody to the TCR/CD3 complex or with the lectin Con A. We now show that the anti-sgp-60 mAb inhibits the activation-induced increase in intracellular Ca2+ concentration. Additional analysis demonstrates that the mAb interferes with the release of Ca2+ from intracellular stores and with the generation of inositol 1,4,5-trisphosphate. Our findings suggest a role for this glycosylphosphatidylinositol-anchored protein in the generation of second messengers in signal transduction through the TCR/CD3 complex in murine T lymphocytes.

Modulation of the intracellular Ca2+ and inositol trisphosphate concentrations in murine T lymphocytes by the glycosylphosphatidylinositol-anchored protein sgp-60

Stimulation of T lymphocytes via the TCR/CD3 complex initiates a series of intracellular biochemical events. Among the earliest cellular responses are the stimulation of the turnover of phosphatidylinositol and an increase in the intracellular Ca2+ concentration. The significance of these second messengers for distal cellular responses such as lymphokine production or cell proliferation is not understood. We have previously shown that hamster mAb to the murine glycosylphosphatidylinositol-anchored protein sgp-60 can inhibit IL-2 production, IL-2R expression, and cell proliferation, events normally observed after stimulation of T cells with an antibody to the TCR/CD3 complex or with the lectin Con A. We now show that the anti-sgp-60 mAb inhibits the activation-induced increase in intracellular Ca2+ concentration. Additional analysis demonstrates that the mAb interferes with the release of Ca2+ from intracellular stores and with the generation of inositol 1,4,5-trisphosphate. Our findings suggest a role for this glycosylphosphatidylinositol-anchored protein in the generation of second messengers in signal transduction through the TCR/CD3 complex in murine T lymphocytes.

[The role on the analgesia of entopeduncular nucleus]

L-glutamic acid, bicuculline (a GABA receptor antagonist), lidocaine and GABA were injected into entopeduncular and habenular nuclei respectively in rats. Pain threshold was measured by the latency of avoidance response (tail-flick) elicited by radiant heat exposure before and after intracerebral injection. Microinjection of different concentration of L-glutamic acid (25 nmol/L.0.5 microliter-1, 50 nmol/L.0.5 microliter-1, 100 nmol/L.0.5 microliter-1) into bilateral entopeduncular nuclei resulted in increases of pain threshold in a dose-dependent manner. Similar increase of pain threshold could also be observed by microinjection of 200 nmol/L GABA.0.5 microliter-1 into bilateral habenular nuclei. Both the effect of GABA and that of glutamate, could be antagonized by 0.2% bicuculline. The results mentioned above indicate that GABAergic fibers are involved in the analgesic effect of entopeduncular-habenular complex.

[Cloning and characterization of the genome of human papilloma virus type 16 in China]

The cloning and characterization of a whole genome of human papillomavirus type 16(7.9kb) and a 5.4kb subgenomic fragment were studied. They were cloned after insertion in plasmid pAt153, using its unique BamH1 site. The full-length genome and subgenomic fragment were designated HPV16Z and HPV16F respectively. After analysis by 16 endonucleases, no new restriction site was found in HPV16Z in comparison with the standard strain. A new BamH1 site was observed at the 750 bp position in HPV16F. Using HPV16Z as molecular probe, 296 cervix and vagina biopsies from Xiang Yuan County of Shanxi Province were tested by means of Coslot hybridization under highly stringent conditions (Tm-17 degrees C). The experimental result showed that the HPV16Z infection rates of patients with chronic cervicitis, vaginitis, cervical pre-cancer lesions (CINI-CINIII), cervical cancer were 11.9% (17/143), 17.3% (14/81), 46.8% (22/47), and 68% (17/25) respectively. The findings indicate that HPV16Z infection is prevalent in the cervix pre-cancer lesion and cervical cancer in the high risk region.

Radiosensitization and inhibition of deoxyribonucleic acid repair in rat glioma cells by long-term treatment with 12-O-tetradecanoylphorbol 13-acetate

Patients with brain tumors often undergo radiotherapy, and the cellular resistance is a major obstacle. It has been suggested that protein kinase C (PKC) may be one of a number of important regulatory enzymes in cell response to ionizing radiation. We therefore investigated the effect of PKC depletion on deoxyribonucleic acid (DNA) damage and repair after radiation in C6 cells using a microgel electrophoresis method to explore the role of PKC in glioma radioresistance. When cells are embedded in agarose on slides, lysed, and subjected to an electric field, broken DNA is able to migrate toward the anode. A significant increase in the length of DNA migration was observed in the cells exposed to irradiation. Inhibition of PKC activity by prolonged treatment with 12-O-tetradecanoylphorbol 13-acetate (TPA) or staurosporine, a potent PKC inhibitor, before irradiation enhanced radiation-induced DNA damage and attenuated the repair of damaged DNA. The half-times of DNA repair in parent C6 cells and PKC-depleted C6 cells were about 30 and 60 min, respectively, and the extent of DNA migration was still seen in the PKC-depleted cells even at 120 min after irradiation. In addition, the C6 cell clonogenicity after irradiation was also attenuated by long-term exposure of the cells to 12-O-tetradecanoylphorbol 13-acetate. These data suggest that PKC may play an important role in regulating the cell response to irradiation. The inhibitors of PKC might represent a new class of pharmacological agents to manipulate the radiosensitivity of gliomas.

In vivo release of water-soluble drugs from stabilized water-in-oil-in-water (W/O/W) type multiple emulsions following intravenous administrations using rats

The in vivo release of four water-soluble drugs, cefadroxil, cephradine, antipyrine and 4-aminoantipyrine, from a stabilizing water-in-oil-in-water (W/O/W) type multiple emulsion was studied using rats. The W/O/W type multiple emulsion used in this study could be stabilized for 30 d after preparation at room temperature and also for 24 h in pH 7.4 isotonic phosphate buffer or in rat plasma at 37 degrees C. The cefadroxil and cephradine concentrations in rat plasma following intravenous administrations of their W/O/W type multiple emulsions containing drugs were considerably prolonged compared with those of respective aqueous solutions. Sustained-releasing properties of cefadroxil and cephradine from W/O/W type multiple emulsions could be explained by the mechanism underlying the long residence time of W/O/W type multiple emulsions and delay-release of drugs from the W/O/W type multiple emulsions circulated with rat blood stream. However, antipyrine and 4-aminoantipyrine decreased rapidly following W/O/W type multiple emulsions and these plasma profiles coincided precisely with those following intravenous administration of the aqueous solutions of drugs. These in vivo releasing data correlated with in vitro drug release observation stated in the previous papers.

Measurement of rat brain perfusion by NMR using spin labeling of arterial water: in vivo determination of the degree of spin labeling

In vivo NMR experiments are performed to determine the degree of spin labeling for measurement of tissue perfusion by NMR using spin labeling of arterial water by adiabatic fast passage. Arterial water spins are labeled using flow in the presence of a field gradient and B1 irradiation to fulfill the conditions for adiabatic fast passage spin inversion. It is demonstrated that the NMR-measured tissue perfusion is not affected by changing the degree of spin labeling as long as the degree of spin labeling is determined and accounted for according to the model used for calculating perfusion. By measuring the degree of spin labeling with different arterial blood flow velocities induced by different arterial pCO2, it is also demonstrated that, when spin labeling is carried out by adiabatic fast passage, the degree of spin labeling is not affected by changes in arterial blood flow velocity over a broad range.

Analytical study of temperature oscillations in living tissues

A nonlinear, time-delay differential equation is postulated as a possible structure to describe the temperature dynamics at a point inside living tissue. The presented analysis explains how this differential equation can lead to four different temperature response types that have been previously observed in vivo.

DNA strand exchange catalyzed by proteins from vaccinia virus-infected cells

Vaccinia virus infection induces expression of a protein which can catalyze joint molecule formation between a single-stranded circular DNA and a homologous linear duplex. The kinetics of appearance of the enzyme parallels that of vaccinia virus DNA polymerase and suggests it is an early viral gene product. Extracts were prepared from vaccinia virus-infected HeLa cells, and the strand exchange assay was used to follow purification of this activity through five chromatographic steps. The most highly purified fraction contained three major polypeptides of 110 +/- 10, 52 +/- 5, and 32 +/- 3 kDa. The purified protein requires Mg2+ for activity, and this requirement cannot be satisfied by Mn2+ or Ca2+. One end of the linear duplex substrate must share homology with the single-stranded circle, although this homology requirement is not very high, as 10% base substitutions had no effect on the overall efficiency of pairing. As with many other eukaryotic strand exchange proteins, there was no requirement for ATP, and ATP analogs were not inhibitors. Electron microscopy was used to show that the joint molecules formed in these reactions were composed of a partially duplex circle of DNA bearing a displaced single-strand and a duplex linear tail. The recovery of these structures shows that the enzyme catalyzes true strand exchange. There is also a unique polarity to the strand exchange reaction. The enzyme pairs the 3' end of the duplex minus strand with the plus-stranded homolog, thus extending hybrid DNA in a 3'-to-5' direction with respect to the minus strand. Which viral gene (if any) encodes the enzyme is not yet known, but analysis of temperature-sensitive mutants shows that activity does not require the D5R gene product. Curiously, v-SEP appears to copurify with vaccinia virus DNA polymerase, although the activities can be partially resolved on phosphocellulose columns.

Glutamine enhancement of structure and function in transplanted small intestine in the rat

Total parenteral nutrition is required by all patients in need of small bowel transplantation. Untoward side effects of total parenteral nutrition include atrophy and hypofunction of the small intestine. Glutamine, the preferred fuel for the enterocyte, is presumably present in insufficient amounts in diets given to patients with intestinal dysfunction. In a rat model of total parenteral nutrition and small bowel transplantation, this study investigated the following: (1) whether glutamine improves graft structure and function, (2) the optimal route of glutamine delivery (intravenous vs direct infusion into the graft), and (3) the effect of glutamine on ultrastructure of the graft enterocyte. Lewis rats underwent small bowel transplantation as a Thiry-Vella graft and received total parenteral nutrition for 14 days while assigned to one of four infusion groups: 2% intravenous glutamine; 2% intravenous isonitrogenous mixture, nonessential amino acids (control); 2% glutamine into the graft; or 2% nonessential amino acids into the graft (control). Graft mucosal villous height, villous surface area, crypt depth, weight, protein, deoxyribonucleic acid content, glucose absorption, and enterocyte ultrastructure were then evaluated. Infusion of glutamine directly into the graft significantly increased mucosal villous height (p = .045), surface area (p = .029), and glucose absorption (p = .004) when compared with controls. Intravenous glutamine infusion significantly increased mucosal villous height (p = .002), surface area (p = .001), weight (p = .005), and glucose absorption (p = .04) when compared with controls. Most enterotrophic and functional benefits of glutamine were not significantly different between intravenous infusions and direct administration into the graft.(ABSTRACT TRUNCATED AT 250 WORDS)

Sensitization of C6 glioma cells to radiation by staurosporine, a potent protein kinase C inhibitor

The effect of staurosporine, a potent protein kinase C (PKC) inhibitor, on the sensitivity to radiation has been investigated in C6 glioma cells. Pretreatment of C6 cells with staurosporine at the concentrations over 1 nM resulted in an enhancement of sensitivity to irradiation. At a concentration of 5 nM, staurosporine caused significant radiosensitization of the cells, either it was administered 1) before and during irradiation, or 2) continuously before, during, and after irradiation, with a reduced D0 (the 37% survival dose) from 3.8 Gy to 2.9 Gy and 3.0 Gy, respectively, (p < 0.03). Since the viability of C6 cells was not affected by staurosporine alone at the concentrations tested, the radiosensitizing effect of staurosporine was considered to be mediated via suppression of PKC. Furthermore, another potent PKC inhibitor H-7, 1-(5-isoquinoline-sulfonyl)-2-methylpiperazine dihydrochloride, also sensitized C6 cells to irradiation, while HA1004, N-(2-guanidinoethyl)-5-isoquinolinesulfonamide hydrochloride a potent inhibitor for cAMP-dependent protein kinase, failed to affect the radiosensitivity in this cells. Therefore, staurosporine-induced sensitization of C6 cells to radiation may at least in part be mediated by its inhibitory activity for PKC. Staurosporine represents a new agent for radiosensitization and may prove usefulness in studying the mechanisms responsible for radio-resistance and -sensitivity in glioma cells.

An observation on flash evoked cortical potentials and Qigong meditation

The purpose of this study was to investigate the functional state of the cerebral cortex during Qigong meditation with flash visual evoked potentials (F-VEPs) recorded from the occipital scalp in four groups of adults. The first group included 14 subjects who had exercised in Neiyang Gong for 0.5-5.5 years. The second group was composed of 12 subjects who had practiced Neiyang Gong for only 0.5-3 months. Eleven subjects who had never practiced Qigong before made up the third group and served as control. Eleven Qigong practitioners constituted the fourth group. It was found that F-VEP amplitudes were increased in the first group and decreased in the fourth group with the exception of one subject during Qigong meditation. No significant changes were found in the second group and controls. The results were discussed and it is shown that Qigong mediation may have either facilitative or inhibitory effects on the visual cortex depending on the Qigong methods practiced by different individuals.

Rabbit skeletal muscle glycogenin. Molecular cloning and production of fully functional protein in Escherichia coli

Glycogenin is a self-glucosylating protein involved in the initiation reactions of glycogen synthesis. Initiation occurs in two stages, requiring first the covalent attachment of a glucose residue to Tyr-194 of glycogenin and then elongation to form an oligosaccharide chain. The latter reaction is known to be catalyzed by glycogenin itself. The glycogenin sequence determined from the protein by Campbell and Cohen (Campbell, D. G., and Cohen, P. (1989) Eur. J. Biochem. 185, 119-125) was used to design oligonucleotide probes to screen a rabbit muscle lambda gt11 library. A cDNA was isolated that predicted an amino acid sequence identical to that of Campbell and Cohen, except that Cys residues replaced Ser-88 and Leu-97. Northern analysis indicated a strongly hybridizing message of 1.8 kilobases, present in most tissues including skeletal muscle, but much weaker in kidney and scarcely detectable in liver. A much weaker 3-kilobase message was also detected in muscle. Polymerase chain reaction was used to isolate DNA fragments encoding a portion of glycogenin from rat and cow. The sequence of this segment was > 90% identical at the amino acid level across the three species, indicating that glycogenin is a highly conserved protein. Using the pET-8c vector, the glycogenin protein was expressed in Escherichia coli. Incubation of the recombinant glycogenin with UDP-[14C]glucose and Mn2+ resulted in labeling of the glycogenin protein, indicating that the recombinant glycogenin was enzymatically active and capable of self-glucosylation. Furthermore, after incubation with UDP-glucose, the recombinant glycogenin could serve as a substrate for glycogen synthase, leading to the production of high M(r) polysaccharide. Therefore, production of functional glycogenin did not require the intervention of any other mammalian protein.

Distribution of cellular carbohydrate moieties in human dysontogenetic brain tumors, especially in craniopharyngioma and epidermoid/dermoid

Cellular carbohydrate moieties of 65 human dysonotogenetic brain tumors (craniopharyngioma, epidermoid/dermoid, Rathke cleft cyst, germinoma and non-germinomatous germ-cell tumors) and 60 common brain tumors (glioma, meningioma, neurinoma and pituitary adenoma) were investigated histochemically using sections from Ulex europaeus (UEA-1), Dolichos biflorus (DBA), peanut (PNA) and soybean (SBA), and with anti-blood group A and LewisY (LeyY) antibodies. In craniopharyngiomas and epidermoid/dermoids, it was found that PNA and SBA binding sites existed in suprabasal cells of the epithelium, and that antigen of either blood group A or H (demonstrable by UEA-1) existed in more differentiated epithelial cells compared to the results reported in normal human skin epidermis. Rathke cleft cysts were stained with PNA or SBA, and two out of three Rathke cleft cysts also expressed either H or A antigen. In addition, DBA binding sites, as well as LeY antigen, were frequently seen in craniopharyngiomas and Rathke cleft cysts, but they were entirely absent in the epithelium of epidermoid/dermoid. On the other hand, PNA and SBA reactivities was also found in common brain tumors, while blood group A, H and LeY antigens and DBA reactivity were almost absent in these tumors. These findings demonstrate that carbohydrate moieties such as those of blood group antigens reported to be found in human skin epidermis exist in a similar form in craniopharyngioma, epidermoid/dermoid and the Rathke cleft cyst. The identification of blood group A, H and LeY antigens and DBA reactivity in brain tumors seems to be considerably limited and specific.(ABSTRACT TRUNCATED AT 250 WORDS)

Proliferative assessment of craniopharyngioma and epidermoid by nucleolar organizer region staining

The histologic distinction between craniopharyngioma and epidermoid is equivocal. Eight craniopharyngiomas and ten epidermoids (including three dermoids) as well as nine rat (Wistar) abdominal skins that acted as control were investigated by a silver colloid method for nucleolar organizer regions (Ag-NORs). The mean number of Ag-NORs in at least 200 cells of both basal (columnar) epithelial cells and suprabasal (prickle) cells was evaluated. It was found that the mean number of Ag-NORs in basal cells of epidermoid and rat skin was significantly greater than that in suprabasal cells (P < 0.001 in nine of ten epidermoids and in all rat skins). On the other hand, of eight craniopharyngiomas, the mean Ag-NOR number in basal cells was not significantly different from that in suprabasal cells in five cases, and, further, the former was significantly smaller than the latter in the other three cases (P < 0.01 in two and P < 0.05 in one). These findings suggest that a stepwise maturation of the epithelial cells like that in mammalian skin epidermis exists in epidermoids but not in craniopharyngiomas. In craniopharyngiomas, the maturation of the epithelial cells seems to be considerably limited or lost from the aspect of proliferative potential as assessed by Ag-NOR score, which indicates neoplastic growth of craniopharyngiomas. Ag-NOR staining may thus be a useful method to distinguish craniopharyngioma from epidermoid.

Interaction of epirubicin with other cytotoxics and anti-emetic drugs

Epirubicin is usually administered in combination with other cytotoxics. Few pharmacological studies address whether relevant clinical interactions occur in vitro between these drugs. This study investigated whether epirubicin interacted with other cytotoxics or anti-emetics. The following drugs were prepared at pharmacological concentrations, etoposide (200 micrograms/ml), 5-fluorouracil (120 micrograms/ml), cisplatin (100 micrograms/ml), vincristine (100 micrograms/ml) and cyclophosphamide (1 micrograms/ml) respectively were admixed with epirubicin (1 micrograms/ml). Epirubicin was analysed by high performance liquid chromatography using in-line UV and fluorescence detectors. Experiments were performed in quadruplicate. No significant interactions were noted. The experiments were repeated for stemetil and maxolon. Maxolon did not interact with epirubicin but stemetil produced an interfering peak in the assay. We conclude that interaction studies are an important step in the workup of chemotherapy regimens.

Immunological consequences from exposure to benzo(a)pyrene during pregnancy

Progeny and maternal immune status after benzo(a)pyrene (BP) exposure of mothers at mid-pregnancy is disrupted in fetal liver (FL), in spleen and in thymus during pregnancy and postnatally. Mice suffer deficiencies in splenic and thymic mixed lymphocyte responses (MLR), and disorientations of T antigen expressing cells, punctuated by exorbitant increases in Lyt2, especially in FL. FL Lyt2 do not suppress an MLR, while Lyt1 mediate suppression. Isolated Thy1 show a weak response to Concanavalin A; FL Thy1 weakly express an MLR. Maternal macrophages and progeny B cells are also functionally abnormal. Thus, BP induces generalized immune deficiency that may affect ontogeny and which is potentially deleterious to health.

Mechanisms of protective effects of berbamine on ischemia/reperfusion injury in isolated rat heart

Isolated perfused rat heart model was used to observe the protective effects of berbamine on myocardial ischemia/reperfusion injury. The hearts were significantly injured by 40 min global ischemia followed by 20 min reperfusion. Berbamine could significantly improve heart function, prevent ventricular fibrillation, reduce CK release, preserve Na,K-ATPase activity, and reduce Na+ gain and K+ loss during ischemia and Ca2+ overload during reperfusion. With the use of low temperature ESR technique, in hearts subjected to 40 min ischemia and 15 sec reperfusion, oxygen-centered free radical signals became much more intense. In the presence of berbamine, these signals decreased. Results showed that berbamine could alleviate myocardial ischemia/reperfusion injury. This effect might be due to: 1) preserved myocardial Na,K-ATPase activity and inhibition of sodium overload at the end of ischemia, which might further lead to attenuation of reperfusion-induced calcium overload, and 2) reduction of oxygen free radical generation during reperfusion.

Enhancement of radiosensitivity by tamoxifen in C6 glioma cells

The antiestrogen drug tamoxifen, which is used extensively in the treatment of breast cancer, has also been reported to inhibit the proliferation of some estrogen receptor-negative cell lines, including malignant glioma in vitro. To explore the possible role of tamoxifen in the treatment of malignant glioma, we have investigated its effects on cell growth and radiosensitivity in C6 glioma cells using a colony-forming assay and a tetrazolium-formazan growth rate assay. Pretreatment of C6 cells with tamoxifen resulted in dose-dependent inhibition of cell growth and enhancement of the antitumor effects of ACNU and irradiation. The radiosensitivity of the treated cells was enhanced by the administration of 5 mumol/L of tamoxifen either before and during irradiation or continuously before, during, and after irradiation [37% survival dose (Do) = 2.68 +/- 0.19 and 2.64 +/- 0.04 Gy, respectively, P < 0.01)], as compared with controls (Do = 3.79 +/- 0.25 Gy). In addition, protein kinase C activity was also inhibited by tamoxifen at the concentration in which the radiosensitivity was augmented in C6 cells. Taken together, our results demonstrate a synergistic effect of tamoxifen with radiation on intracellular damage in C6 glioma cells, which may in part be due to the inhibition of protein kinase C, suggesting that tamoxifen serves as a useful agent in combination therapy of glioma.

[Protective effects of Panax quinquefolium saponin on oxidative damage of cultured rat cardiac cells]

When cultured cardiac cells of rats were exposed to X-XOD containing medium, the absolute values of electronic parameters were decreased the percentage of beating clusters reduced and the microscopic structure destroyed. PQS significantly converted all the indices, which shows that PQS can protect the cells from oxidative damage.

Clinical implications of decreased retinoblastoma protein expression in acute myelogenous leukemia

The retinoblastoma (RB) protein levels in blast-enriched mononuclear fractions from the peripheral blood of 33 newly diagnosed patients with acute myelogenous leukemia were studied. Ten patients who had previously been treated were also analyzed, nine of whom had achieved prior complete remission. Low RB protein expression was found in 13 of 43 (30%) of the acute myelogenous leukemia patients as determined by Western blotting and immunochemical analysis. Of particular interest among the 20 newly diagnosed patients treated with the same therapeutic regimen, the median survival was 39 days for those with low RB protein expression compared to 333 days for those with high levels of RB protein expression in their leukemic cells (P less than or equal to 0.02). This preliminary study suggests that decreases of RB protein expression in peripheral blood of myeloid leukemic cells occur frequently and may be associated with shortened survival of acute myelogenous leukemia patients.

[Shortcomings of esophagogastric stapling device and their correction and prevention]

From 1985 to 1991, 202 patient with cancer of the esophagus or gastric cardia were resected with esophagogastric stapling device. The shortcomings were: 1. Necessity of second stapling-5 cases, and 2. Defective performance-9.1% (19/207 times) which was due to; a. failed coupling (7 times), b. incomplete resection (6 times), c. tearing of the muscular layer (4 times), d. gastric tube stapled into the stoma (1 time), and e. fall-off of thread from the purse-string suture at the esophageal stump (1 time). The correction procedures were: 1. Repair by hand suture (6 times), 2. Repeated stapling (5 times), 3. Repair of muscle tear by silk sutures (6 times), and 4. Second resection (2 times). Prevention of these shortcomings are discussed. The authors believe the stapling device can not replace manual suturing.

Hepatic macrophage malfunction in rats with obstructive jaundice and its biological significance

The present study was designed to investigate the pathophysiology of obstructive jaundice by analyzing the function of hepatic macrophages and their role in immune responses and homeostasis in rats. The phagocytic index, determined by the rate of disappearance of 51Cr-endotoxin from the peripheral blood after intravenous injection, was increased in obstructive jaundice 2 weeks after bile duct ligation. The superoxide production of isolated hepatic macrophages and peripheral blood monocytes, measured by the superoxide dismutase inhibitable ferricytochrome c reduction method, was increased. Prostaglandin E2 release, measured by RIA, was markedly increased in rats with obstructive jaundice, but there was no significant difference in interleukin-1 release between jaundiced and control rats. The flow-cytometric analysis of surface molecules of hepatic macrophages showed decreased expression of interleukin-2 receptor in rats with obstructive jaundice. Thus, the functions of hepatic macrophages in rats with obstructive jaundice were impaired. This malfunction may disturb the immunoregulatory network and metabolism, although the exact implications of the altered function of hepatic macrophages have not yet been clarified.

The stress distribution of the lumbar spine and disc degeneration

A three-dimensional finite element model of the lumbar motion segment was developed to study the effect of disc degeneration upon stress distribution in the lumbar spine. The results showed that after degeneration of the intervertebral disc, the stress distribution and load transmission of the lumbar spine are significantly changed. It is concluded that these changes provide a biomechanical basis for understanding the etiology of spinal canal stenosis and nerve root entrapment.

[Survey of suicidal mortality rate in several districts of Sichuan province]

A survey of the suicidal mortality rates in two cities and six districts in Sichuan province was carried out from 1980 to 1988 by the authors. The average suicidal mortality rate (ASMR) in these districts from 1980 to 1988 was 15.5/10(5), and the population and suicidal mortality rate positively correlated, r = 0.53. The ASMR in the male was 14.9/10(5), in the female 17.1/10(5), in the urban area 9.4/10(5), in the rural area 21/10(5), and the ASMR in the urban area was higher than that in the rural area (P < 0.05). The peak age of suicidal mortality was around twenty years.

Crystal structure of the major histocompatibility complex class I H-2Kb molecule containing a single viral peptide: implications for peptide binding and T-cell receptor recognition

To study the structure of a homogenous major histocompatibility complex (MHC) class I molecule containing a single bound peptide, a complex of recombinant mouse H-2Kb, beta 2-microglobulin (beta 2m), and a fragment of the vesicular stomatitis virus (VSV) nuclear capsid protein, VSV-(N52-59) octapeptide (Arg-Gly-Tyr-Val-Tyr-Gln-Gly-Leu), was prepared by exploiting a high-yield bacterial expression system and in vitro cocomplex formation. The structure of mouse H-2Kb revealed its similarity to three human class I HLA molecules, consistent with the high primary sequence homology and common function of these peptide-presenting molecules. Electron density was located in the peptide-binding groove, to which a single peptide in a unique conformation was unambiguously fit. The peptide extends the length of the groove, parallel to the alpha-helices, and assumes an extended, mostly beta-strand conformation. The peptide is constrained within the groove by hydrogen bonding of its main-chain atoms and by contacts of its side chains with the H-2Kb molecule. The amino-terminal nitrogen atom of the peptide forms a hydrogen bond with the hydroxyl group of Tyr-171 of H-2Kb at one end of the groove, while the carboxyl-terminal oxygen forms a hydrogen bond with the hydroxyl group of Tyr-84 at the other end. Since the amino acids at both ends are conserved among human and mouse MHC molecules, this anchoring of each end of the peptide appears to be a general feature of peptide-MHC class I molecule binding and imposes restrictions on its length. The side chains of residues Tyr-3, Tyr-5, and Leu-8 of the VSV octapeptide fit into the interior of the H-2Kb molecule with no appreciable surface exposure, a finding in support of previous biological studies that showed the importance of these residues for binding. Thus, the basis for binding of specific peptide sequences to the MHC class I molecule is the steric restriction imposed on the peptide side chains by the architecture of the floor and sides of the groove. The side chains of Arg-1, Val-4, and Gln-6 and the main-chain of Gly-7 of the octapeptide are exposed on the surface of the complex, thus confirming their availability for T-cell receptor contact, as previously demonstrated by T-cell recognition experiments.

Polymorphism at codon 72 of the p53 gene in human acute myelogenous leukemia

A common polymorphism at codon 72 of the p53 gene in patients with acute myelogenous leukemia (AML) was analyzed by single-strand conformation polymorphism assay and sodium dodecyl sulfate polyacrylamide-gel electrophoresis of immunoprecipitated 35S-labeled P53 protein. No association between this polymorphism and a marked predisposition to AML was found. The half-lives of these two polymorphic forms of P53 were equivalent in normal phytohemagglutinin-stimulated lymphocytes, while the P53 Pro72 isoform was found to be twice as stable as the Arg72 isoform in Daudi cells.

P53 gene mutations in acute myelogenous leukaemia

A polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) assay was used to identify the exons which contained point mutations in the conserved regions (exons 4-8) of the p53 gene in 49 acute myelogenous leukaemia (AML) patients. SSCP analysis in our study was consistent with the results of subsequent direct DNA sequencing in detecting point mutational change in exons 5 and 8 of one AML patient and in exons 7 and 8 of two additional AML patients. The mutations were located at codons 245 and 273, which have been found in many other tumours, and codons 178 and 290, which have not been reported previously. All of the p53 proteins in which we detected point mutations were immunoprecipitated by the p53 monoclonal antibody PAb 240, which has been shown to recognize a mutant conformation of p53 protein. Thus, our results indicate that functional inactivation of the p53 gene by point mutational change might be one of the mechanisms underlying disease progression of AML.

Characterization of cis-acting elements regulating transcription from the promoter of a constitutively active rice actin gene

The promoter of the constitutively expressed rice (Oryza sativa) actin 1 gene (Act1) is highly active in transformed rice plants (W. Zhang, D. McElroy, and R. Wu, Plant Cell 3:1150-1160, 1991). A region 834 bp upstream of the Act1 transcription initiation site contains all the regulatory elements necessary for maximal gene expression in transformed rice protoplasts (D. McElroy, W. Zhang, J. Cao, and R. Wu, Plant Cell 2:163-171, 1990). We have constructed a series of Act1 promoter deletions fused to a bacterial beta-glucuronidase reporter sequence (Gus). Transient expression assays in transformed rice protoplasts, as well as transformed maize cells and tissues, identified two distinct cis-acting regulatory elements in the Act1 promoter. A 38-bp poly(dA-dT) region was found to be a positive regulator of Act1 promoter activity. Deletion of the poly(dA-dT) element lowered Gus expression by at least threefold compared with expression produced by the full-length Act1 promoter. By gel retardation and footprinting, we identified a ubiquitous rice protein which specifically recognizes this poly(dA-dT) element in the constitutively active Act1 promoter. A CCCAA pentamer repeat-containing region was found to be a negative regulator of the Act1 promoter in transformed rice protoplasts. Transient expression assays in different maize cells and tissues with use of the Act1 deletion constructs suggested that the CCCAA pentamer repeat region functions in a complex tissue-specific manner. A CCCAA-binding protein was detected only in root extracts.

Altered conformation of the p53 protein in myeloid leukemia cells and mitogen-stimulated normal blood cells

Expression of the normal p53 gene promotes cell differentiation, maturation and apoptosis. The mutant p53 gene, which does not function normally, is frequently expressed at elevated levels in tumor cells [for review see Lane, D.P. & Benchimol, S. (1990). Genes Dev., 4, 1-8]. We have analysed the expression of and mutational change in the p53 gene in the peripheral blood cells of 49 primary acute myeloid leukemia (AML) patients. The p53 protein levels were elevated in 37 patients (75%) when measured by immunoprecipitation with antibodies PAb1801 and PAb421, which recognize both normal and mutant forms of the protein. The p53 protein from 32 of these 37 patients was immunoprecipitated by PAb240, which recognizes a conformation of p53 protein associated with point mutations. However, point mutations were detected by single-stranded conformation polymorphism (SSCP) assay and direct sequencing in only three patients at codons 178, 245, 273 and 290. Growth stimulation of normal lymphocytes also generated p53 which was immunoprecipitable by PAb240. Thus, alteration of p53 conformation, rather than acquisition of point mutations, could be the mechanism underlying the increased proliferation of myeloid cells in most AML patients.

Laparoscopic cholecystectomy: report of 42 cases

Our initial experience with laparoscopic cholecystectomy for cholecystitis and cholelithiasis was reviewed in 42 patients and the data were compared with those of 21 patients who underwent conventional open cholecystectomy previously. Only one patient required conversion to an open operation. Three of the 42 patients had minor complications without death in laparoscopic cholecystectomy. The mean time for the laparoscopic cholecystectomy was 100 +/- 40 min, as compared with 79 +/- 21 min for the open cholecystectomy. The average postoperative hospital stay was 11.4 +/- 7.1 days for the laparoscopic procedure and 35.5 +/- 15.4 days for the conventional procedure. The laparoscopic cholecystectomy offers the patients shortened hospitalization and lower complications and can replace the conventional open cholecystectomy in large degree, at least in the uncomplicated cases.