Differentiating human from animal isolates of Cryptosporidium parvum

We analyzed 92 Cryptosporidium parvum isolates from humans and animals by a polymerase chain reaction/restriction fragment length polymorphism method based on the thrombospondin-related anonymous protein 2 gene sequence. Used as a molecular marker, this method can differentiate between the two genotypes of C. parvum and elucidate the transmission of infection to humans.

[Change of serum lipid, apolipoprotein during cholesterol gallstone formation in rabbit model]

In order to study the formation of cholesterol gallstone through rabbit model which was induced by high cholesterol diet (HCD), we investigated the rabbits' serum lipoprotein cholesterols and apolipoprotein (apo) at 1 week (1w), 2 weeks (2w), 3 weeks (3w) and 4 weeks (4w) in comparison with those of a control group respectively. The results were as follows: (1) of 10 rabbits subjected to experiment, 4, 6, and 7 rabbits were found to have induced-cholesterol gallstones in the 2w, 3w and 4w groups respectively. (2) The serum concentrations of total cholesterol (TC), triglyceride (TG), phospholipid (PL), low density lipoprotein cholesterol (LDL-C) and very low density lipoprotein chloesterol (VLDL) increased significantly (1w, 2w, 3w and 4w groups vs control group, P < 0.05), especially in the 3w and 4w groups; the surum concentrations of high density lipoprotein cholesterol and its subfractions (HDL-C, HDL2-C, HDL3-C) decreased slightly (vs control group, P > 0.05). (3) The serum contents of apoB100, apoC II and apoC III increased significantly (vs control group, P < 0.05), especially in the 3w and 4w groups; the serum apoA I reduced gradually in 1w, 2w and 3w groups, and decreased greatly in 4w group (vs control group, P < 0.05). The results demonstrated that owing to the intake of high cholestrol diet with the passage of time, the increased concentrations of serum VLDL-C, apoB, apoC II and apoC III possibly caused an enhanced secretion of biliary cholesterol into bile; that the decreased serum apoA I level might reduce the secretion of anti-nucleating factor into bile. All of these factors and changes may play important roles during the formation of cholesterol gallstones.

Adrenomedullin is a potent stimulator of osteoblastic activity in vitro and in vivo

Adrenomedullin is a 52-amino acid vasodilator peptide produced in many tissues, including bone. It has 20% sequence identity with amylin, a regulator of osteoblast growth, and circulates in picomolar concentrations. The present study assesses whether adrenomedullin also acts on osteoblasts. At concentrations of 10(-12) M and greater, adrenomedullin produced a dose-dependent increase in cell number and [3H]thymidine incorporation in cultures of fetal rat osteoblasts. This effect was also seen with adrenomedullin-(15-52), -(22-52), and -(27-52), but adrenomedullin-(40-52) was inactive. These effects were lost in the presence of amylin blockers, suggesting they were mediated by the amylin receptor. Adrenomedullin also increased [3H]thymidine incorporation into cultured neonatal mouse calvaria but, unlike amylin, did not reduce bone resorption in this model. Adrenomedullin stimulated phenylalanine incorporation into both isolated osteoblasts and calvaria. When injected daily for 5 days over the calvariae of adult mice, it increased indexes of bone formation two- to threefold (P < 0.0001) and increased mineralized bone area by 14% (P = 0.004). It is concluded that adrenomedullin regulates osteoblast function and that it increases bone mass in vivo. The potential of this family of peptides in the therapy of osteoporosis should be further evaluated.

[Detection of bacterial DNA from cholesterol gallstones by NP-PCR and its clinical significance]

To search for bacterial DNA sequences in cholesterol gallstones with negative bacterial culture. We used nested primers polymerase chain reaction (NP-PCR) technique to amplify bacterial gene fragments were amplified in vitro from DNA extracted from cholesterol gallstones. Comparative 16S ribosomal RNA sequence analysis was used for elucidation of bacterial identification. The gallbladder gallstones of 30 patients were analyzed. Bacterial DNA was found in the stones of 26 patients. There was no difference either in cholesterol and water content or in harboring bacterial DNA of gallstones. E. coli-related DNA fragments were found in the stones of 8 patients (26.67%). Propionibacteria type DNA was found in the stones of 7 patients (23.33%). Stones of 2 patients (6.67%) harbored bacterial gene fragments with similarity of Streptococcus pyogenes. A more heterogeneous sequence collection was found in 7 patients (23.33%) and could be assigned to the multiple bacterial infections. Another stones of 2 patients (6.67%) had bacterial DNA with lower molecularweight which might be related to some unidentified bacteria. The results suggested that most cholesterol gallstones harbor bacterial DNA. It is important to determine whether these microorganisms are innocent bystanders or active participants in cholesterol gallstone formation.

Hormonal activation of the striatum and the nucleus accumbens modulates paced mating behavior in the female rat

Sexual behavior in the female rat has both sensorimotor and motivational components, which can be distinguished when the female rat is able to pace the rate of copulation. The experiments reported were conducted to determine whether estrogen application to the striatum and/or nucleus accumbens affects pacing behavior. In order to induce sexual receptivity, ovariectomized rats received sequential bilateral implants of 17beta-estradiol followed by progesterone into the ventromedial nucleus of the hypothalamus. Then, bilateral implants of 17beta-estradiol or cholesterol were administered into either the dorsolateral striatum or the nucleus accumbens. Pacing behavior was tested 4 hr later. It was found that intrastriatal application of estradiol significantly facilitated the percent exits exhibited after copulatory contact, whereas application of estradiol in the nucleus accumbens affected the return latency. To determine whether estrogen in the striatum or nucleus accumbens normally plays a role in pacing behavior, intrastriatal or intra-accumbens implants containing the steroidal antiestrogen ICI 182,780 or vehicle were given to ovariectomized female rats treated systemically with estrogen and progesterone. The antiestrogen treatment decreased the percent exits when delivered to the striatum and affected return latency when delivered to the nucleus accumbens. The results indicate that estrogen acts directly in the striatum and in the nucleus accumbens to differentially modulate specific components of pacing behavior.

Efficient selection and regeneration of creeping bentgrass transformants following particle bombardment

We have established an efficient genetic transformation system for creeping bentgrass (Agrostis palustris Huds.) using particle bombardment. The transformation was performed using the plasmid pZO1052 which contains the reporter β-glucuronidase (uidA) gene and the selectable marker hygromycin phosphotransferase (hph) gene. Transformed calli and plants were obtained via particle bombardment followed by selection of transformants on medium containing 200 mg/l of hygromycin. An average of 4.6 resistant colonies per bombardment were obtained. Southern analysis confirmed the integration of foreign genes in 19 of 21 putative transformants, indicating that selection by hygromycin was highly effective.

Synthesis of Uniform Ferric Oxide Particles from Deionized Colloids

A modified method was employed to prepare monodispersed colloidal particles of ferric (hydrous) oxide. The method contains three steps: (i) preparation of uniform nuclei of ferric hydrous oxide via a so-called instantaneous nucleation method; (ii) purification of the nuclei suspension via dialysis; (iii) aging of the purified nuclei suspension in a reflux reactor at certain pH. Cubic and pseudocubic alpha-Fe2O3 monodisperse particles which are much smaller than the cubic alpha-Fe2O3 particles obtained from the same reactant through a usual method were produced by aging needle like nuclei at a lower pH. A close-packed three-dimensional QDs (quantum dots) superlattice structure 40 nm in edge length with cubic geometry was formed by self-aggregation between spherical amorphous ferric hydrous oxide nuclei 3-5 nm in diameter. The growth processes of the two kind particles were also illustrated. This study showed an approach to prepare smaller particles from aqueous metal salt solutions in relatively higher concentration, and ordered QDs superlattice structure by controlled self-aggregation of QDs in hydrosol.

Induction of protective antibodies in Saimiri monkeys by immunization with a multiple antigen construct (MAC) containing the Plasmodium vivax circumsporozoite protein repeat region and a universal T helper epitope of tetanus toxin

Previous attempts in inducing protective immunity against Plasmodium vivax in human volunteers and nonhuman primates with recombinant circumsporozoite (CS) proteins have been unsuccessful, largely due to the failure of generating antibodies against the protective B epitope AGDR in the CS protein repeat region. We report here an immunization study in Saimiri monkeys with a multiple antigen construct (MAC) containing the P. vivax CS protein repeat region and a T helper epitope of tetanus toxin formulated in different adjuvants. Monkeys immunized three times with MAC in copolymer P1005, copolymer P1005 plus RaLPS, or MF-75 had titers of antibodies against CS repeat, sporozoites and the protective B epitope AGDR significantly higher than those immunized with MAC in alum or PBS (P < 0.05). Antibody levels in animals that received P1005 were maintained at high level for 7 months after the last immunization. Upon challenge with 10000 sporozoites 2 weeks after the last immunization, 75% (three of four) of monkeys from the alum group, 50% (three of six) of monkeys from the P1005 plus RaLPS group, 40% (two of five) of monkeys from the P1005 group, 33% (two of six) of monkeys from the MF-75 group, and 17% (one of six) of monkeys from the MAC alone group were fully protected. When immunized animals were challenged again with 30000 sporozoites 22 weeks after the last immunization. 40% (two of five) monkeys from the P1005 group were fully protected. The remaining (three) in this group developed low parasitemia (< 2000 parasites mm-3 of blood) after significantly longer prepatent period (P < 0.05). In addition, 17% (one of six) of monkeys each from the P1005 plus RaLPS and MF-75 groups were also fully protected. Protected animals had higher levels of prechallenge anti-AGDR antibody titers than unprotected (1933 vs 281 for the first challenge, P > 0.05; 21527 vs 196 for the rechallenge, P < 0.05). Anti-AGDR antibody titers were positively correlated with the prepatent period of infected animals (r = 0.42 for the first challenge, P > 0.05; r = 0.60 for the rechallenge, P < 0.05) and negatively correlated with the peak parasitemia (r = -0.39 for the first challenge, P < 0.05; r = 0.50 for the rechallenge, P < 0.05). The results suggested that when combined with the use of potent adjuvants and T helper epitopes, MAC subunit vaccines may potentially offer protection against malaria infection.

[Photographic diagnosis for common intraorbital tumors]

OBJECTIVE

To compare and analyze the modern photographic methods used for localization and analysis of the nature of intraorbital tumors.

METHODS

B-scan, CT scan and magnetic resonance imaging (MRI) were used to examine six types of common intraorbital tumor (20 cases for each type).

RESULTS

Each method can locate and show the nature of the lesions, and B-scan has a better value to display internal structure and dynamics of orbital lesions. CT can discover the lesions and exactly show their locations, while MRI is more valuable to display the optic nerve tumor and the extension of intraorbital tumor to extraorbital regions.

CONCLUSIONS

All the above methods can locate and show the nature of intraorbital tumors, and each has its own special defects and advantages which can be complementary to one another.

Genetic polymorphism among Cryptosporidium parvum isolates: evidence of two distinct human transmission cycles

We report the results of molecular analysis of 39 isolates of Cryptosporidium parvum from human and bovine sources in nine human outbreaks and from bovine sources from a wide geographic distribution. All 39 isolates could be divided into either of two genotypes, on the basis of genetic polymorphism observed at the thrombospondin-related adhesion protein (TRAP-C2) locus. Genotype 1 was observed only in isolates from humans. Genotype 2, however, was seen in calf isolates and in isolates from a subset of human patients who reported direct exposure to infected cattle or consumed items thought to be contaminated with cattle faces. Furthermore, experimental infection studies showed that genotype 2 isolates were infective to mice or calves under routine laboratory conditions, whereas genotype 1 isolates were not. These results support the occurrence of two distinct transmission cycles of C. parvum in humans.

Formation of hydroxyeicosatetraenoic acids from hemozoin-catalyzed oxidation of arachidonic acid

Hemozoin, a heme byproduct of hemoglobin digestion by malaria parasites, is released into the blood stream of the host upon lysing of infected erythrocytes. Since heme-compounds are potent catalysts of lipid peroxidation, we evaluated the catalytic ability of Plasmodium falciparum-derived hemozoin to oxidize arachidonic acid to hydroxyeicosatetraenoic acids (HETEs). Hemozoin, beta-hematin, and hematin all catalyzed the formation of 15-, 12- and 5-HETE as major products. Although there were no significant differences in total amounts of HETEs generated by hemozoin relative to hematin or beta-hematin, there were significant differences in the proportions of certain isomers. 15-HETE was the predominant isomer generated by hemozoin catalysis while 5-HETE was the major product formed by hematin catalysis. Since HETEs are important vasoactive mediators, the non-enzymatic oxidation of arachidonic acid by hemozoin catalysis may contribute to some of the pathophysiology associated with severe and cerebral malaria.

Quantitation of RT-PCR amplified cytokine mRNA by aequorin-based bioluminescence immunoassay

We described here a bioluminescence-based immunoassay for the quantitation of RT-PCR amplified cytokine mRNA. This technique uses a standard RT-PCR procedure, with the following modifications. The forward primer in the PCR reaction is labeled with a 5' biotin molecule. Following PCR, a digoxigenin-conjugated oligonucleotide probe is hybridized to the target biotin-labeled DNA template. The hybridized duplex is captured onto a streptavidin-coated microtiter plate. The bound product is quantitated by adding digoxigenin-specific antibodies conjugated with the photoprotein aequorin. The amount of specific DNA captured onto the plate is quantitated by triggering the bioluminescence reaction through the addition of calcium ions. This technique detected as low as 40 amol of amplified cytokine products, or 500 copies of templates when 27 PCR cycles were used. The high sensitivity of this technique enables the quantitation of target DNA during the exponential phase of the PCR reaction. The aequorin-bioluminescence assay is an alterative non-radioactive method for the quantitation of PCR products.

Influence of adjuvants on murine immune responses against the C-terminal 19 kDa fragment of Plasmodium vivax merozoite surface protein-1 (MSP-1)

The immunogenicity of a yeast-expressed 19 kDa fragment of P vivax MSP-1 in the presence of different adjuvant formulations was evaluated. ICR mice were immunized with the 19 kDa antigen, using Freund's, alum, and block copolymer P1005 in water-in-oil (W/O) or oil-in-water (O/W) emulsions with or without detoxified lipopolysaccharide (RaLPS) as adjuvants. Five weeks following immunization with the antigen, mice were boosted with asexual blood-stage antigens. Three weeks after the last immunization with the 19 kDa antigen, mice from the Freund's group and most groups that received P1005 as adjuvant had higher total IgG titres than those that received alum as adjuvant or antigen alone. Antibody responses after the antigen immunization were predominantly of the IgG1 isotype, but mice in the Freund's and P1005 (W/O or O/W emulsion with or without RaLPS) groups also had high titres of IgG2a and IgG2b. Antibody titres against merozoites increased in all groups after the parasite antigen boost. IgG2a levels in the group that received antigen in P1005 plus RaLPS in the W/O emulsion were higher than those receiving Freund's, alum or the other copolymer adjuvants. The high IgG2a titres in this group were associated with reduced IL-10 production.

Plasmodium falciparum: involvement of additional receptors in the cytoadherence of infected erythrocytes to microvascular endothelial cells

The involvement of additional ligands in the cytoadhesion of PRBC to endothelial cells was studied by the use of human microvascular endothelial cells (HMEC-1), brain microvascular endothelial cells (HBEC-51), umbilical vein endothelial (HUVEC), and C32 melanoma cells as well as soluble CD36, ICAM-1, and thrombospondin in the adhesion assays. Immunostaining showed that ICAM-1 and thrombospondin were expressed by all cell lines, whereas CD36 and VCAM-1 were expressed constitutively only by C32 melanoma cells and HBEC-51, respectively; none of these cells had basal expression of E-selectin. Bindings of the parental HB3 parasite strain to HMEC-1 and HUVEC were higher than that to HBEC-51 and C32 melanoma cells. Selections by panning the parental HB3 through HMEC-1 (HB3EC-6 line) or C32 melanoma cells (HB3C32-6 to HMEC-1 was higher than that to C32 melanoma cells. Antibody or peptide blockade against CD36, ICAM-1, and thrombospondin or preincubation of target cells with TNF-alpha and IFN-gamma did not significantly alter the binding intensity of HB3EC-6 to HMEC-1 and HB3C32-6 to C32 melanoma cells. Preincubation of HMEC-1 with IL-4, however, reduced its binding with HB3EC-6. In vitro selection did not enhance the binding of PRBC to plate-bound CD36 or thrombospondin; binding to ICAM-1 was negligible. The binding of both selected lines was inhibited by dextran sulfate and sulfatides, but not by chondroitin sulfate A. These results suggested that in addition to CD36 and thrombospondin, sulfated glycoconjugates were probably concurrently utilized by these PRBC as receptors. Experiments with freshly isolated Kenyan parasites indicated that they also exhibited a similar mechanism of binding to endothelial cells.

Immunosuppressive properties of plasma and lymphocytes from the human retroplacental blood

The retroplacental compartment in which maternal blood is in direct and continuous contact with trophoblasts derived from the fetus seems to be the place where maternal and fetal cells regulate each others' activities. To assess the role of the retroplacental compartment in the immune regulation of pregnancy, 10 healthy pregnant women were selected for evaluation of the immune activity of their lymphocytes and plasma from the retroplacental blood. The results showed that the proliferation and cytotoxic capacity of these lymphocytes, but not of maternal peripheral lymphocytes, against fetal cells were significantly inhibited in undirect mixed lymphocyte culture and direct cell-mediated cytotoxic assay, respectively. The plasma from retroplacental blood showed significant immunosuppressive properties and depressed the proliferation of maternal peripheral lymphocytes stimulated by fetal HLA as well as the cytotoxic activity of these cells against the fetal lymphocytes. The present data suggest that the retroplacental compartment seems to be an immunosuppressive barrier, protecting the fetus from maternal rejection.

[Orbital exenteration associated with cavity reconstruction]

OBJECTIVE

A surgery was designed for the cosmetic improvement after orbital exenteration.

METHODS

Exenteration associated with simultaneous or secondary orbital reconstruction was performed on 22 patients, including transplantation of temporalis muscle in 11 cases, temporoparietal fascia with vascular pedicle in 10 cases and latissimus dorsi myocutaneous free flap in one case.

RESULTS

Except 7 patients who needed palpebral resection and orthopedic operation the second time, all of them were fitted well with ocular prostheses postoperatively and obtained satisfactory cosmetic results.

CONCLUSION

Among the three methods of orbital reconstruction, the temporoparietal fascia transplantation is the best.

Sulfated polyanions inhibit invasion of erythrocytes by plasmodial merozoites and cytoadherence of endothelial cells to parasitized erythrocytes

Sulfated proteoglycans have been shown to be involved in the binding of sporozoites of malaria parasites to hepatocytes. In this study, we have evaluated the effect of sulfated glycosaminoglycans on the invasion of erythrocytes by Plasmodium falciparum merozoites and cytoadherence of parasitized erythrocytes (PRBC) to endothelial cells. Invasion of erythrocytes by HB3EC-6 (an HB3 line selected for high binding to endothelial cells) was inhibited by dextran sulfate 500K, dextran sulfate 5K, sulfatides, fucoidan, and heparin but not by chondroitin sulfate A. With the exception of sulfatides, the invasion-inhibitory effect was not mediated by killing of parasites. Cytoadherence of HB3EC-6 to human microvascular endothelial cells (HMEC-1) and inhibited by these sulfated glycoconjugates. The highly sulfated dextran sulfate 500K had the highest inhibitory effect on both invasion and cytoadherence, whereas the positively charged protamine sulfate promoted cytoadherence. Because preincubation of PRBC with sulfated glycosaminoglycans and treatment of target cells with heparinase had no significant inhibition on cytoadherence, it is unlikely that sulfated glycoconjugates are used directly by endothelial cells as cytoadhesion receptors. In an vivo experiment, we found that the administration of dextran sulfate 500K to CBA/Ca mice infected with Plasmodium berghei ANKA reduced parasitemia and delayed the death associated with anemia. These observations suggest that sulfated polyanions inhibit the invasion of erythrocytes by merozoites and cytoadherence of PRBC to endothelial cells by increasing negative repulsive charge and sterically interfering with the ligand-receptor interaction after binding to target cells.

Tricyclic antidepressants inhibit human natural killer cells

The commonly used antidepressants imipramine, amitriptyline, and nortriptyline were found to significantly inhibit human natural killer (NK) cell-mediated cytolysis in vitro and suppress the stimulation of NK cells by IFN-gamma. This is a previously unrecognized biologic property of these drugs with psychotropic activity. Tricyclic antidepressants did not decrease effector-target cell conjugation formation, nor did they induce target cell resistance to NK lysis, indicating that the drugs might interfere with the killing mechanism of the effector cells. Kinetic data reveal that the drug interference is related to an early postbinding event in the activation of NK cells. Results also showed that the inhibitory effect of tricyclic antidepressants on human NK cell activity occurred in parallel to an increase in intracellular cyclic GMP concentration. However, the attenuation in the cyclic GMP formation by methylene blue, a selective inhibitor of soluble guanylate cyclase, was not accompanied by a corresponding increase in NK cell cytolytic activity. It is suggested that the stimulation of cyclic GMP was not directly involved in the inhibitory effect of antidepressants on NK cells and perhaps was a secondary phenomenon. This immune cell modulatory property of tricyclic antidepressants seems to indirectly provide evidence for the concept that human brain neurons and NK cells might share regulatory system(s).

[Relationship between SCE points and G-banding location in patients with nasopharyngeal carcinoma]

Using a technique for simultaneous demonstration of G bands and SCE, we analyzed the SCE frequencies, cell cycle kinetics, distribution of SCE points and "hot spots" which correlate with fragile sites, proto-oncogenes locus in cultured peripheral blood lymphocytes in 20 untreated patients with nasopharyngeal carcinoma (NPC). The SCE frequencies were found to be higher in patients as compared with controls (P < 0.01). The SCE points of patients were significantly higher than those of controls in chromosome 1,2,3,4,5,7,8,12,13,14,17 (P < 0.05), indicating the chromosome instability of NPC patients. We identified 17 points as high frequency SCE hot spots, and found that 29.41% SCE hot spots fragile sites and proto-oncogenes were localized at the same bands. The distribution of SCE points and chromosome structure were discussed.

Differential transcription of the human spermidine/spermine N1-acetyltransferase (SSAT) gene in human lung carcinoma cells

The expression of spermidine/spermine N1-acetyltransferase (SSAT), the rate-limiting enzyme in the catabolism of polyamines, is highly regulated by a number of factors including the natural polyamines and their analogues. The phenotype-specific cytotoxicity that occurs in response to a class of polyamine analogues, the diethylpolyamines, is associated with a phenotype-specific superinduction of SSAT in human non-small-cell lung carcinomas, whereas in non-responding cell types, including the small-cell lung carcinomas, the superinduction of SSAT does not occur. In this study, we have investigated the molecular basis of this phenotype-specific SSAT induction in human lung carcinoma cells in response to N1,N12-diethylspermine (BESpm). To facilitate the study of transcriptional regulation, we have cloned and characterized 11 kb of the human SSAT locus, including 3500 bp of the 5' promoter region. Nuclear run-on transcription studies suggest that the initial induction of SSAT results from an increase in the rate of gene transcription. Results from Northern blot analysis and ribonuclease protection assays indicate a differential expression of SSAT mRNA between the analogue-responsive H157 and non-responsive H82 cells. There is no detectable SSAT mRNA in H82 cells, even after a 24-h analogue treatment, whereas SSAT mRNA in H157 cells was detectable by Northern blot analysis and increased more than 100-fold following drug exposure. Furthermore, nuclear run-on transcription assays do not detect any active transcription of SSAT gene in either treated or untreated H82 cells. These results indicate that at least one component of the phenotype-specific induction of SSAT appears to be due to differences in transcriptional regulation of the gene. In addition, mapping of DNase I-hypersensitive sites of the SSAT gene suggest that the cell type-specific promoter/enhancer utilization may control the expression of the SSAT gene in differentially sensitive cell types in vivo.

Isolation of a polyamine transport deficient cell line from the human non-small cell lung carcinoma line NCI H157

In an effort to study the mechanism underlying the observed phenotype-specific response of human lung cancer cell lines to a polyamine analogue, N1,N12-bis(ethyl)spermine(BESpm), we have isolated a BESpm resistant cell line from the BESpm-sensitive large cell lung carcinoma line NCI H157. The mutant line exhibits identical growth rates in the presence or absence of the analogue. However, the overall growth of mutant cells reaches stationary phase earlier than that of the parental cells. In contrast to the parental cells, where a superinduction of spermidine/spermine N1-acetyltransferase (SSAT) is associated with BESpm toxicity, treatment of this resistant line with BESpm did not induce SSAT mRNA or enzyme activity. BESpm treatment was not effective in depleting the intracellular polyamine pools and very low intracellular BESpm levels were detected. This BESpm resistance is not mediated by multidrug resistance (MDR) protein, since these cells maintain their sensitivity to the antineoplastic agent adriamycin. Treatment of these cells with methylglyoxal bis(guanylhydrazone) (MGBG), an AdoMetDC inhibitor which enters cell using polyamine transport system, shows no inhibition of cell growth. Our data suggest that these mutant cells are deficient in polyamine transport. Consistent with this hypothesis, exogenous polyamines did not prevent difluoromethylornithine (DFMO) induced growth inhibition in the mutant cells.

Efficacy of albendazole and fenbendazole against Giardia infection in cattle

Efficacies of albendazole and fenbendazole in suppressing Giardia cyst output of infected calves were evaluated in two clinical trials. In the first trial, 18 naturally infected calves were allocated to an untreated control group (n = 9) and an albendazole-treated group (n = 9). Calves in the treated group were given 20 mg/kg-1 oral albendazole once daily for 3 days. Compared to controls, treated calves showed 98.5%, 97.6% and 90.8% reductions in cysts per gram of feces (cpg) 1, 2 and 6 weeks respectively after the start of treatment. In a second trial, 13 infected calves were allocated to an untreated control group (n = 6) and a fenbendazole-treated group (n = 7). Calves in the treated group were given 10 mg kg-1 fenbendazole orally twice daily for 3 days. Compared to the control group, treatments reduced cpg counts by 100%, 98.5% and 59.5% 1, 2, and 3 weeks respectively after the start of treatment. Both albendazole and fenbendazole appeared to be effective in suppressing cyst excretion by Giardia-infected calves.

Nitric oxide synthase pathway may mediate human natural killer cell cytotoxicity

The present study provides evidence that the human natural killer (NK) cell effector mechanism causing target cytolysis has a requirement for L-arginine. In a deficient medium (DM) containing only salts, buffer system and glucose, NK cell-mediated cytotoxicity was found to decrease by 70% as compared to that obtained in a complete medium (CM). However, adding L-arginine to such DM could restore the activity of NK cells to the normal level. Many other components of CM, such as serum, glutamine and vitamins did not improve NK cell-mediated killing in DM. When all amino acids except L-arginine were added to DM only a partial recovery of NK cell functional cytolysis was seen. L-arginine enhanced the NK cell activity in a dose-dependent manner. Additionally, the inhibitor of both inducible and constitutive nitric oxide synthase, N-monomethyl-L-arginine (L-NMMA) inhibited NK cytolytic activity in DM supplemented with L-arginine indicating participation of nitric oxide (NO). The results also show that the stimulatory effect of L-arginine on human NK cell-mediated cytotoxicity was accompanied by an increase in NO formation as determined by accumulation of nitrite and citrulline. L-NMMA gave a dose-dependent reduction in NO generation as well. The nitrite and citrulline production dose-dependently correlated with not only the concentration of L-arginine in the cultivation medium, but also the enhanced NK cell-mediated cytolysis. Taken together, these findings could define a L-arginine/NO-linked effector mechanism in human NK cells. Nitrite and citrulline were not formed when NK cell-mediated target cell killing took place in a L-arginine-free DM supplemented with additives. Thus, it appears as if human NK cells may cause target cell killing via both NO-dependent and -independent processes.

Significant induction of spermidine/spermine N1-acetyltransferase without cytotoxicity by the growth-supporting polyamine analogue 1,12-dimethylspermine

The superinduction of the polyamine catabolic enzyme spermidine/spermine N1-acetyltransferase (SSAT) has been implicated in the cell type-specific cytotoxic activity of some polyamine analogues. We now report that one polyamine analogue, 1,12-dimethylspermine (DMSpm), produces a large induction of SSAT with no significant effects on growth in the human large cell lung carcinoma line, NCl H157. This cell line has been demonstrated to respond to other analogues with SSAT superinduction and cell death. Treatment of the lung cancer cell line with DMSpm produces a rapid increase in SSAT activity and a near complete depletion of the natural polyamines. Additionally, DMSpm supports cell growth in cells which have been depleted of their natural polyamines by the ornithine decarboxylase inhibitor, 2-difluoromethylornithine. The current results suggest that significant induction of SSAT can occur in the absence of cytotoxicity when the inducing polyamine analogue can support growth and that increased SSAT activity alone is not sufficient for cytotoxicity to occur.

[Diagnosis and management of tumors with orbito-cranial access]

To identify the characteristics and extent of orbitocranial tumor for the selection of operative methods, 64 patients with the tumor were studied with clinical materials, primarily CT and magnetic resonance imaging (MRI) appearances. The lesions were found in the orbit, cranium and orbito-cranium boundary parts and their diagnoses in regard to localization and identification could be made. Based on the preoperative diagnosis of an orbito-cranial tumor, its location, character, secondary changes and operation(s) in the past, a surgical approach was designed. The resection of a tumor could be completed in once or in several times of operation. 64 operations were performed on 53 patients and other therapies were given to the other 11 patients. The operative methods included orbitotomy via anterior route, 21 times via lateral route and 30 times via transcranial route. The operative results suggest that the transcranial route be complicated and have more complications; preoperatively, the operative indication be strictly selected and intraoperatively, ophthalmologists closely cooperate with neurological surgeons.

Cyclic guanosine 3',5'-monophosphate mediates 3-morpholinosydnonimine-induced inhibition of human natural killer cells

Nitric oxide (NO) donors were used to investigate the effect of NO on and the role of cyclic GMP in the regulation of human natural killer (NK) cell function. NO-producing drugs, molsidomine and its metabolite 3-morpholinesydnonimine (SIN-1), inhibited NK cell-mediated cytotoxicity significantly at 0.04-5 mM. At 1 mM, SIN-1 completely inhibited NK cell activity while molsidomine decreased NK cell-mediated cytolysis by 35% of the control value. These data suggest that NO from exogenous NO-donors may down-regulate NK cell cytotoxic function. The stimulatory effect of interferon-gamma (IFN-gamma) on human NK cell-mediated killing could not overtake the NK cell inhibition induced by the NO releasing drugs, indicating different modes of action for IFN-gamma and SIN-1. The results in the present study also showed that SIN-1 (1 mM) stimulated cyclic GMP production 37-fold in NK cells. In the presence of 0.5 mM IBMX, a phosphodiesterase inhibitor, the increase in cyclic GMP was even more pronounced, demonstrating a relation between cyclic GMP stimulation and NK cell inhibition by SIN-1. Further evidence for mediation via cyclic GMP was provided by the finding that methylene blue (20 microM), an inhibitor of soluble guanylate cyclase, decreased both the inhibition of SIN-1-induced NK cell cytotoxicity as well as cyclic GMP formation. Moreover, membrane-penetrating cyclic GMP and its analogues inhibited NK cell-mediated cytolysis significantly. Molsidomine was without effect on cyclic GMP levels. Our data indicate that cyclic GMP may play a role in human NK cell regulation and suggest that the inhibitory effect of cGMP may be elicited by NO.

Cytoplasmic Ca2+ inhibits the glucose transporter of human erythrocytes

The effect of Ca2+ on the glucose transporter of human erythrocytes was investigated. The results showed that extracellular Ca2+ had no effect. But, the glucose transport of erythrocytes was markedly inhibited due to the increase in cytoplasmic Ca2+ concentration by addition of ionophore A23187. The Ca2+ inhibition exhibited a dose-dependent manner with an apparent half maximal concentration of 250 microM and could not be recovered by 10 mM EGTA. Unlike Ca2+, Mg2+ did not affect the glucose transporter.

[Changes of HDL-receptor of hepatic cell membrane in rabbit model of calcium bilirubinate cholangiolithiasis]

HDL-receptor of the hepatic cell membrane and Fch level of the hepatic tissue in the rabbit model of calcium bilirubinate cholangiolithiasis were examined. The results showed: (1)the HDL-receptors' Bmax of the biliary obstruction and infection (BOI) and biliary obstruction (BO) groups decreased during the 1st week after operation (P < 0.01); they were only 69.09% and 49.09% of that in the control group respectively, and the lowered level continued until the 6th week; the Kd values of BOI and BO groups were not different from that of the control group during the 1st week, but they were significantly higher in the 6th week after operation (P < 0.01); (2)the Fch levels of the hepatic tissue were slightly decreased in all experimental groups (P < 0.05). We concluded that under the conditions of biliary obstruction and infection, there was a disorder of the HDL receptors of hepatic cell membrane. At the early stage of biliary obstruction and infection, the receptors decreased in number, and at the later stage, the affinity changed and less HDL entered into the hepatic cell. Then the precurser cholesterol pool for BA biosynthesis narrowed. Thus, BA secreted from the liver cells into genetic elements possibly promote the formation of the calcium bilirubinate gallstones.

[Alterations of oxygen free radicals in rabbit models and its relation to formation of pigment gallstones]

The experimental rabbits were divided into three groups. In the first group the common bile ducts were loosely ligated and contaminated by E. coli (BOI); in the second group the common bile ducts were only loosely ligated (BO); and the third group was the control group (Con). Alterations of oxygen free radicals were studied in all these models. The result showed that alterations of the partial hepatic oxygen free radicals (OFR), the hepatic prostaglandin E2 (PGE2) and the pigment gallstones were similar. There was a positive correlation among them (P < 0.05). In group BOI, these indexes were higher than in group BO. It is suggested that oxygen free radicals are possibly responsible for the formation of pigment gallstones through the pathway from oxygen free radicals to promote the production of prostaglandin E2, glycoprotein and pigment gallstones at last E. coli may aggravate the formation of pigment gallstones by increasing hepatic oxygen free radicals.

Infection pattern of Cryptosporidium and Giardia in calves

Faecal samples were collected weekly over a 3 month period from 0- to 20-week-old calves on an Ohio dairy farm, and examined for Cryptosporidium oocysts and Giardia cysts by a quantitative direct immunofluorescence assay. Oocysts and cysts were detected as early as 4 days of age. Shedding of Cryptosporidium oocysts peaked at 1 week and was low by 3 weeks. Some calves, however, continued to pass low numbers of oocysts. Shedding of Giardia cysts peaked at 2 weeks of age with high levels maintained until 7 weeks of age. Most calves continued to pass low numbers of Giardia cysts after weaning. Cumulative infection rates for both Cryptosporidium parvum and Giardia sp. were 100%.

Quantitative microdialysis determination of extracellular striatal dopamine concentration in male and female rats: effects of estrous cycle and gonadectomy

Sex differences in basal extracellular striatal dopamine concentrations in gonadectomized male and female rats have been reported previously. In the current experiment, estrous cycle-dependent variation, sex differences and the effect of gonadectomy on extracellular striatal dopamine concentrations were determined using quantitative microdialysis. Female rats were found to have significantly higher extracellular striatal dopamine concentrations in proestrus and estrus than in diestrus or after ovariectomy. In contrast, castration of male rats had no effect on extracellular striatal dopamine concentrations. Thus, endogenous ovarian hormones, but not testicular hormones, modulate extracellular striatal dopamine concentrations in rats.

[Changes in serum lipoprotein cholesterol in rabbit model of calcium bilirubinate cholangiolithiasis]

The lithogenic process of cholangiolithasis is still not understood clearly. In this study, several serum lipoprotein cholesterol, the bile BA level, etc. in the rabbit model of calcium bilirubinate cholangiolithiasis was examined. The main results included: (1) The concentrations of HDL-ch and HDL2-ch in the serum decreased in all the experimental groups (P < 0.01; P < 0.05), except HDL-ch in the BO 1W group (P > 0.05) compared with the control group. The concentrations of HDL2-ch in the BOI 1W and the BOI 6W groups were lower than those in the BO 1W and the BO 6W groups respectively (P < 0.05); the both concentrations of Fch and HDL3-ch in the BOI and the BO groups were much higher than those in the control group (P < 0.01). (2) The bile T-BA level was lower in the both BOI groups than that in the control group (P < 0.05). It began to decrease in the BO group during the first week, but it was not significant in statistical difference (P > 0.05). During the 6th week the level of the bile acid (BA) was much lower than that in the control group (P < 0.05). According to the above results, it may be concluded that in the formation of calcium bilirubinate gallstones, caused by the biliary obstruction and infection, there is a disorder in the lipoprotein metabolism.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative efficacy of moxidectin and ivermectin against hypobiotic and encysted cyathostomes and other equine parasites

Efficacies of moxidectin and ivermectin were compared in four groups of eight ponies with natural parasite infections: placebo (Control), oral moxidectin gel at 0.3 mg kg-1 of body weight (Mox 0.3), oral moxidectin gel at 0.4 mg kg-1 of body weight (Mox 0.4), and oral ivermectin paste at 0.2 mg kg-1 of body weight (Ivermectin). Fecal samples were taken 0 and 2 weeks after treatment. Animals were necropsied and worms were collected 2 weeks after treatment. Moxidectin and ivermectin showed similar efficacy (99%) against adult cyathostomes, Strongylus spp., Triodontophorus spp. and Habronema muscae. Both drugs were also more than 98% effective against luminal cyathostome and Oxyuris equi fourth stage larvae (L4). Neither drug was effective (0-10.1%) against hypobiotic early third stage cyathostome larvae (EL3). Moxidectin was moderately effective (62.6-79.1%) in removing encysted cyathostome late third stage larvae (LL3) and L4, whereas ivermectin was ineffective (0%) against these stages. By contrast, ivermectin was 95.4% effective against Gasterophilus spp. third instar stage, whereas moxidectin was only 0-20.4% effective.

Prevalence of Cryptosporidium and Giardia infections on two Ohio pig farms with different management systems

The prevalence of Cryptosporidium and Giardia infections in pigs was investigated by the use of a direct immunofluorescence assay on two Ohio farms with different management systems. Cryptosporidium and Giardia infections were detected only in weanlings on the farm with slotted and wire floors, but in both weanlings and nursing piglets on the farm with porous concrete floors. Giardia infection was also detected in sows on the latter farm. The farm with porous concrete floors had a significantly higher Cryptosporidium infection rate in nursing piglets and Giardia infection rates in weanlings than the farm with slotted and wire floors. Sows were implicated as the source of both Cryptosporidium and Giardia infections for nursing piglets.

Periparturient rise in the excretion of Giardia sp. cysts and Cryptosporidium parvum oocysts as a source of infection for lambs

The possibility of a periparturient rise (PPR) in the excretion of Cryptosporidium parvum oocysts and Giardia duodenalis-type cysts and its implications in the epidemiology of these 2 pathogens were investigated. Fecal samples were taken from 32 lambing ewes every 2 wk from 4 wk before lambing until 8 wk after the start of lambing. Samples from both ewes and lambs were examined with a quantitative immunofluorescence assay. Excretion of Giardia sp. cysts by ewes increased at 2 wk prepartum, peaked at zero and 4 wk postpartum, and returned to low levels at 6 and 8 wk postpartum. Some ewes also excreted C. parvum oocysts at the start of lambing. Excretion rates and intensities of Giardia sp. cysts by lambs were high, whereas those of C. parvum oocyst excretion were light. The PPR in excretion of Giardia sp. cysts by ewes was considered to be the major source of giardiasis for lambs. Excretion of C. parvum oocysts by ewes at parturition also played a role in initiating cryptosporidiosis in lambs.

Epidemiology of equine Cryptosporidium and Giardia infections

Prevalence and infection patterns of Cryptosporidium and Giardia infections in horses were studied by a direct immunofluorescence staining method. Faecal examinations of 222 horses of different age groups revealed Cryptosporidium infection rates of 15-31% in 66 foals surveyed in central Ohio, southern Ohio and central Kentucky, USA. Only 1 of 39 weanlings, 0 of 46 yearlings, and 0 of 71 mares were positive. Giardia infection was found in all age groups, although the infection rates for foals were higher (17-35%). Chronological study of infection in 35 foals showed that foals started to excrete Cryptosporidium oocysts between 4 and 19 weeks and Giardia cysts between 2 and 22 weeks of age. The cumulative infection rates of Cryptosporidium and Giardia in foals were each 71%. Some foals were concurrently infected with both parasites and excretion of oocysts or cysts was intermittent and long-lasting. The longest duration of excretion was 14 weeks for Cryptosporidium and 16 weeks for Giardia. Excretion of Cryptosporidium oocysts stopped before weaning, while excretion of Giardia cysts continued thereafter. Infected foals were considered the major source of Cryptosporidium infection in foals, whereas infected mares were deemed the major source of Giardia infection in foals. The high infection rate of Giardia in nursing mares suggested a periparturient relaxation of immunity. The results indicated that Cryptosporidium and Giardia infections are common in horses.

Prevention of pathophysiologic and immunomodulatory effects of gastrointestinal nematodiasis in calves by use of strategic anthelmintic treatments

Effects of strategic anthelmintic treatment on pathophysiologic and immunomologic changes induced by infection with Ostertagia ostertagi and Cooperia oncophora were studied in 2 groups, of 12 calves each: an infected group, inoculated with 200,000 mixed O ostertagi and C oncophora third-stage larvae (L3) on day 1; and an infected-treated group, similarly inoculated, but treated with ivermectin at 9 and 33 days. All calves were also inoculated at 12 weeks with Brucella abortus vaccine, at 13 weeks with bovine rhinotracheitis vaccine (bovine herpesvirus 1), and at 14 weeks with a soluble O ostertagi L3 extract, then were allowed to graze on a contaminated pasture. Four calves from each group were slaughtered at 7, 11, and 19 weeks of the study. Calves of the infected group had significantly (P < 0.05) lower weight gain than did those in the infected-treated group (60.90 kg vs 75.86 kg). They also had high plasma pepsinogen and serum gastrin values, and low serum albumin concentration from 2 or 4 weeks. Calves in the infected-treated group had steady weight gain and no significant changes in albumin and gastrin values. They also had less severe abomasal lesions and higher carcass yield. Compared with calves of the infected-treated group, those of the infected group had significantly (P < 0.05) lower blood lymphocyte reactivity to phytohemagglutinin at 14 and 16 weeks, to concanavalin A at 10 weeks, to pokeweed mitogen at 14 weeks, and to soluble O ostertagi L3 extract at 2, 4, and 14 weeks. (ABSTRACT TRUNCATED AT 250 WORDS)