[Studies on the fine stereostructure of taxoids]

The anticancer drug taxol is a new type antimicrotubular drug. The structure-activity relationship study on taxol and its analogs has indicated the importance of the C13 side chain and the C4-C5-C20 epoxypropane group. The crystal structures of 4 taxoids having the basic skeleton with 5/7/6 membered ring and three types of 10 taxoids having the basic skeleton with 6/8/6 membered ring have been analyzed. The effects of the induction by different substructures at C4 on the stereostructures of taxoids were studied, and the relationship between the 6/8/6/4 skeleton and the anticancer activity was discussed from the crystallographic point.

[Investigation on sera prevalence rate of varicella and immunogenicity of varicella vaccine in healthy children]

A whole varicella virus antigen-ELISA method was used to investigate the sera prevalence rate of varicella in 315 healthy children aged 3-7 years. Results showed that the sera positive rate of anti-VZV-IgG was 41.6%. Different prevalence rates in different kindergartens were noticed, characterizing the differences of populations. Immunogenicity of Oka strain attenuated varicella vaccine among children was also studied. No obvious adverse reactions were observed and the seraconversion rate was 85.1%.

[Voice measurement with computer and analysis in normal adult]

Acoustic parameters of 90 normal adults (20-50 years old) were measured with computer. The results showed that fundamental frequency (F0), frequency perturbation quotient (FPQ) and amplitude perturbation quotient (APQ) between male and female in same ages were statistically significant difference. F0 and FPQ were bigger but APQ was smaller in female. FPQ and APQ were significantly related to F0. OCT wasn't obviously different among sexes or ages. The article indicated that voice of adults and the vibration of vocal cords had distinctive characteristics in different sexes or mode of phonation, which could provide objective methods and grounds for clinical voice evaluation.

Apoptosis mediated by Fas but not tumor necrosis factor receptor 1 prevents chronic disease in mice infected with murine cytomegalovirus

The role of Fas- and TNF-receptor 1 (TNF-R1)-mediated apoptosis in the clearance of virally infected cells and in the regulation of the immune response was analyzed after murine cytomegalovirus (MCMV) infection of C57BL/6 (B6)-+/+ mice, Fas-mutant B6-lpr/lpr mice, TNF-R1 knockout B6-tnfr0/0 mice, and double-deficient B6-tnfr0/0 lpr/lpr mice. There was approximately equivalent clearance of MCMV in B6-+/+, B6-tnfr0/0, and B6-lpr/lpr mice, and by day 28 no infectious virus could be detected in the liver, kidney, lung, or peritoneal exudate. However, delayed virus clearance was observed in B6-tnfr0/0 lpr/lpr mice. An acute inflammatory response occurred in the liver, lung, and kidney of all mice, which was most severe 7 d after MCMV infection, but resolved by day 28 in B6-+/+ and B6-tnfr0/0 mice, but not in B6-lpr/lpr or B6-tnfr0/0 lpr/lpr mice. These results indicate that apoptosis mediated by either Fas or TNF-R1 is sufficient for rapid clearance of the virus. However, apoptosis induced by Fas, but not TNF-R1, is required for the downmodulation of the immune response to the virus and prevention of a chronic inflammatory reaction.

Inhibition of tumor necrosis factor alpha decreases inflammation and prolongs adenovirus gene expression in lung and liver

The clinical application of adenoviral gene therapy currently is impeded by the potent host immune response to the virus, which limits the duration of its effects. In these studies, we investigated the role of TNF-alpha and of a soluble TNF receptor (TNF-bp) in the inflammatory response and expression of a lacZ-expressing adenovirus (AdCMVlacZ) in the liver and lung of mice. The expression of the recombinant adenovirus was studied in mouse liver and lung by determining the activity of the lacZ gene product of the adenovirus. The mononuclear cell inflammatory response was determined histologically at different times after intravenous or intranasal administration of AdCMVlacZ. The cytotoxic T cell and antibody response to the adenovirus was determined. Treatment with TNF-bp reduced circulating levels of TNF-alpha, greatly reduced the inflammatory response, and resulted in prolonged expression of lacZ for up to 30 days in the liver and lung after either intravenous or intranasal administration of adenovirus. Treatment with TNF-bp had no effect on anti-adenovirus antibodies and induction of cytotoxic T cells 30 days after administration of AdCMVlacZ. These results indicate that TNF-alpha is the primary factor driving the early inflammatory response leading to elimination of adenovirus-infected cells in the liver and lung and that TNF-bp is capable of inhibiting these effects.

Suppression of Dollar Spot by Hypovirulent Isolates of Sclerotinia homoeocarpa

ABSTRACT Selected hypovirulent isolates of Sclerotinia homoeocarpa were evaluated for efficacy in suppressing dollar spot of turfgrass under growth room and field conditions. Under growth room conditions, hypovirulent isolates Sh12B, Sh09B, or Sh08D of S. homoeocarpa caused 3.4 to 30.4% diseased turf in comparison to virulent isolates Sh48B and Sh14D, which caused 80.2 to 90.2% disease. In treatments that received both virulent and hypovirulent isolates, only hypovirulent isolate Sh12B significantly reduced disease as compared with the control with virulent isolates alone. In a field experiment in 1993 on swards of creeping bentgrass artificially inoculated with a virulent isolate of the pathogen, all treatments containing hypovirulent isolate Sh12B applied as a mycelial suspension, granular mix, or alginate pellets developed significantly less disease (6.3 to 20.8% diseased turf) compared with their respective formulation controls (23.8 to 31.2%). Suppression of dollar spot by treatment with mycelial suspensions of isolate Sh12B was evident up to 45 days postinoculation, and disease suppression was still significant 1 year after application when compared with the water control. Applications of hypovirulent isolate Sh09B did not reduce dollar spot in any treatments. Significant suppression of dollar spot by isolate Sh12B was also observed in the experiment conducted in 1994. In addition, suppression of dollar spot by hypovirulent isolate Sh12B was evaluated on swards with naturally occurring inoculum during 1994. Treatments with a mycelial suspension and alginate pellets of hypovirulent isolate Sh12B significantly reduced dollar spot compared with their respective formulation controls. With few exceptions, there was no statistical difference between treatments with hypovirulent isolate Sh12B and the fungicide chlorothalonil (Daconil 2787). Multiple applications of the hypovirulent isolate did not result in greater suppression of dollar spot as compared with a single application. The results indicate that hypovirulence has potential as an effective strategy for the management of dollar spot.

Calmodulin antagonists inhibit apoptosis of CD4+ T-cells from patients with AIDS

Recent studies indicate that Fas and Fas ligand are involved in apoptosis of T-cells in HIV-infected patients. We have demonstrated that calcium/calmodulin is involved in Fas-mediated apoptosis in human T-cell lines transfected with HIV recombinant cDNA. In the present study, we examined spontaneous apoptosis of T-cells in vitro in peripheral blood obtained from 11 patients with AIDS and 8 HIV-seronegative normal donors and the effect of the calmodulin antagonists, trifluoperazine (TFP) or tamoxifen (TMX), on apoptosis. The results show that: (1) levels of spontaneous apoptosis were higher in PBMCs obtained from patients with AIDS than HIV-negative normal controls and the levels of apoptosis correlated with the severity of disease. (2) The accelerated apoptosis occurred predominantly in CD4+ cells in patients with AIDS. (3) Calmodulin antagonists inhibited the spontaneous apoptosis of CD4+ T-cells from patients with AIDS, which resulted in an increase in the ratio of CD4+ to CD8+ T-cells. (4) The inhibitory effect of calmodulin antagonists on apoptosis was more significant in patients with advanced disease (CDC category C) compared to less severe disease (CDC category B). These results indicate that calmodulin antagonists inhibit HIV-associated apoptosis of CD4+ T-cells, and imply that the calcium/calmodulin play important roles in mediating apoptosis of CD4+ T-cells induced by HIV infection.

Autocrine and Paracrine Apoptosis Are Mediated by Differential Regulation of Fas Ligand Activity in Two Distinct Jurkat T Cell Populations

Fas ligand (FasL) produced by activated T cells mediates autocrine-induced apoptosis to limit T cell expansion. To investigate the regulation of FasL activity, Jurkat cells were stably transfected with a 2.3-kb fragment of human FasL promoter that controlled the expression of a GFP reporter gene. Two populations of Jurkat cells with different levels of GFP expression were obtained. One population constitutively expressed high levels of GFP (GFP+), while the other population expressed low levels of GFP (GFP−). The level of GFP expression in the two populations correlated with their levels of FasL transcription and its functional activity. Autocrine regulation of apoptosis was demonstrated by increased FasL activity after stimulation of GFP− cells with anti-CD3, phorbyl myristyl acetate plus ionomycin, or Con A. Paracrine regulation of apoptosis was suggested by the induction of apoptosis of GFP− cells after coculture with unstimulated GFP+ cells. GFP+ cells exhibited a decreased sensitivity to FasL-mediated apoptosis compared with GFP− cells. Furthermore, the cell surface expression of Fas and CD4 was lower on GFP+ cells than GFP− cells, whereas the expression of CD45RO was higher. A decreased level of IL-2 was produced by GFP+ cells after phorbyl myristyl acetate and ionomycin stimulation. Our results indicate that a subpopulation of T cells that express low levels of FasL and IL-2, which are responsive to up-regulation of these molecules after activation, can undergo apoptosis either by suicide after activation or by a paracrine pathway mediated by T cells that constitutively express higher levels of FasL.

Autocrine and paracrine apoptosis are mediated by differential regulation of Fas ligand activity in two distinct Jurkat T cell populations

Fas ligand (FasL) produced by activated T cells mediates autocrine-induced apoptosis to limit T cell expansion. To investigate the regulation of FasL activity, Jurkat cells were stably transfected with a 2.3-kb fragment of human FasL promoter that controlled the expression of a GFP reporter gene. Two populations of Jurkat cells with different levels of GFP expression were obtained. One population constitutively expressed high levels of GFP (GFP+), while the other population expressed low levels of GFP (GFP-). The level of GFP expression in the two populations correlated with their levels of FasL transcription and its functional activity. Autocrine regulation of apoptosis was demonstrated by increased FasL activity after stimulation of GFP- cells with anti-CD3, phorbyl myristyl acetate plus ionomycin, or Con A. Paracrine regulation of apoptosis was suggested by the induction of apoptosis of GFP- cells after coculture with unstimulated GFP+ cells. GFP+ cells exhibited a decreased sensitivity to FasL-mediated apoptosis compared with GFP- cells. Furthermore, the cell surface expression of Fas and CD4 was lower on GFP+ cells than GFP- cells, whereas the expression of CD45RO was higher. A decreased level of IL-2 was produced by GFP+ cells after phorbyl myristyl acetate and ionomycin stimulation. Our results indicate that a subpopulation of T cells that express low levels of FasL and IL-2, which are responsive to up-regulation of these molecules after activation, can undergo apoptosis either by suicide after activation or by a paracrine pathway mediated by T cells that constitutively express higher levels of FasL.

Cell death mediated by Fas-FasL interaction between glial cells and MBP-reactive T cells

Apoptosis in T cells that have penetrated into the central nervous system (CNS) may be important for the physiological control of T cells with potentially dangerous reactivities to CNS antigens; such control may be dysfunctional in animals suffering from experimental autoimmune encephalomyelitis (EAE). In this study we examined the expression of Fas and FasL genes both in myelin basic protein (MBP)-reactive T cells and in glial cells and the susceptibility of these cells to death induced by Fas/FasL interaction. Both Fas and FasL gene expression is detectable in glial cells and MBP-reactive T cells. Cell death is not unidirectional: when T cells interact with glial cells death can be induced in the former or in the latter population. The ability to induce death of Fas-expressing cells varies greatly among different lines of MBP-reactive T cells, as does resistance to death induction by cells expressing FasL. Moreover, the ability of T cells both to deliver and to resist death signals is a function of their activation status: T cells freshly activated transmit a stronger apoptotic signal to Fas-positive target cells and are also more resistant to FasL-induced suicide. Soluble form of FasL provides a convenient titratable means of delivering death signals via Fas. However, comparison of the susceptibility of different targets to soluble FasL and to FasL expressed on the surface of a transfected glial line revealed differences, suggesting that signals arising from Fas/FasL interaction may be modulated by additional cell-surface molecules.

Fas/Fas ligand signaling during gestational T cell development

Most thymocytes express high levels of Fas Ag (Apo-1/CD95); however, the role of Fas/Fas ligand-mediated apoptosis in thymocyte development remains unclear. During gestational development of thymocytes in C57BL/6(B6) +/+ mice, the highest levels of Fas ligand mRNA and Fas ligand protein expression were detected at gestational day (GD) 15, and there was a ninefold decrease in Fas ligand mRNA expression between GD 15 and 17 accompanied by a sixfold increase in Fas mRNA. Apoptotic thymocytes were first detected in the medulla at GD 15, and increasing numbers of cortical clusters and scattered, single apoptotic cells were present on GD 16 and 17. Thus, early apoptosis correlated with high expression of Fas ligand. High levels of Fas ligand mRNA were maintained throughout gestational development in thymocytes of Fas-deficient B6-lpr/lpr mice, but cortical clusters and scattered apoptotic cells were decreased relative to B6 +/+ mice before GD 17. Kinetic analysis of fetal thymic organ cultures treated with anti-Fas Ab demonstrated that thymocytes become sensitive to Fas-mediated apoptosis during the transition from the CD4-CD8- to the CD4+CD8+ phenotype. More mature CD4+CD8+ thymocytes and CD4+ and CD8+ thymocytes became resistant to Fas-mediated apoptosis after GD 17, despite high expression of Fas. However, low avidity engagement of the TCR on Fas-sensitive CD4+CD8+ thymocytes before GD 17 induced resistance to Fas-mediated apoptosis. The present results indicate that Fas plays a critical role in mediating apoptosis during early gestational thymocyte development and that thymocytes that receive a survival signal through TCR/CD3 become resistant to Fas-mediated apoptosis.

Fas/Fas Ligand Signaling During Gestational T Cell Development

Most thymocytes express high levels of Fas Ag (Apo-1/CD95); however, the role of Fas/Fas ligand-mediated apoptosis in thymocyte development remains unclear. During gestational development of thymocytes in C57BL/6(B6) +/+ mice, the highest levels of Fas ligand mRNA and Fas ligand protein expression were detected at gestational day (GD) 15, and there was a ninefold decrease in Fas ligand mRNA expression between GD 15 and 17 accompanied by a sixfold increase in Fas mRNA. Apoptotic thymocytes were first detected in the medulla at GD 15, and increasing numbers of cortical clusters and scattered, single apoptotic cells were present on GD 16 and 17. Thus, early apoptosis correlated with high expression of Fas ligand. High levels of Fas ligand mRNA were maintained throughout gestational development in thymocytes of Fas-deficient B6-lpr/lpr mice, but cortical clusters and scattered apoptotic cells were decreased relative to B6 +/+ mice before GD 17. Kinetic analysis of fetal thymic organ cultures treated with anti-Fas Ab demonstrated that thymocytes become sensitive to Fas-mediated apoptosis during the transition from the CD4−CD8− to the CD4+CD8+ phenotype. More mature CD4+CD8+ thymocytes and CD4+ and CD8+ thymocytes became resistant to Fas-mediated apoptosis after GD 17, despite high expression of Fas. However, low avidity engagement of the TCR on Fas-sensitive CD4+CD8+ thymocytes before GD 17 induced resistance to Fas-mediated apoptosis. The present results indicate that Fas plays a critical role in mediating apoptosis during early gestational thymocyte development and that thymocytes that receive a survival signal through TCR/CD3 become resistant to Fas-mediated apoptosis.

Application of a Fas ligand encoding a recombinant adenovirus vector for prolongation of transgene expression

An adenovirus vector encoding murine Fas ligand (mFasL) under an inducible control was derived. In vivo ectopic expression of mFasL in murine livers induced an inflammatory cellular infiltration. Furthermore, ectopic expression of mFasL by myocytes did not allow prolonged vector-mediated transgene expression. Thus, ectopic expression of functional mFasL in vector-transduced cells does not appear to confer, by itself, an immunoprivileged site sufficient to mitigate adenovirus vector immunogenicity.

[Comparison of the effects of inhaled nitric oxide and intravasculare regitine on pulmonary gas exchange in young dogs with oleic-acid acute lung injury]

In order to find an agent which truly improves hypoxemia of some serious pediatric lung diseases, the authors examined the independent effects of nitric oxide inhalation and regitine infusion on blood gases, intrapulmonary shunt and hemodynamics in young dogs with oleic-acid acute lung injury. After nitric oxide inhalation, the results showed moderate increases in PaO2 and SaO2 (P > 0.05) and a significant decrease in Qs/Q tau ratio (P < 0.01). There was a significant decrease of PAP(P < 0.05), while SAP remained unchanged. After regitine infusion, however, there were marked decreases in PaO2 and SaO2 (P < 0.01); meanwhile, Qs/Q tau rose (P < 0.05). These suggest that with the presence of pulmonary pathology nitric oxide inhalation may alleviate the elevated pulmonary pressure without alteration in systemic artery pressure; so it can improve pulmonary ventilation-perfusion distribution and cause favorable changes in blood gases. On the other hand, regitine, as a non-selective vasodilator, reduces pulmonary artery pressure at the cost of significant worsening of blood oxygenation and systemic hypotension; so its routine use in childhood pulmonary diseases should be cautiously considered.

Production of rat salivary cystatin S variant polypeptides in Escherichia coli

Cystatins are protein inhibitors of papain and related cysteine proteinases. A series of continuous synthetic peptides corresponding to the entire sequence of rat salivary cystatin was used to localize the binding domains of the cystatin to papain. Several synthetic peptides, one from the aminoterminal sequence (peptide 1-24) and others from the carboxylterminal (peptides 66-79, 66-90, 79-90, 79-114), showed binding to papain, but none of the peptides showed inhibition of papain activity. Three recombinant rat salivary cystatin variants (N-terminal truncated protein lacking amino acid residues 1-9; variant 49-53, in which amino acid residues QVVAG of rat salivary cystatin had been replaced with amino acid residues LVL in mutant protein; and variant 65-78, in which amino acid residues 65-78 had been replaced with amino acids PG in mutant protein) were produced using the Escherichia coli expression system pGex-4T. To generate N-terminal truncated protein the desired coding region of the cystatin gene was amplified by polymerase chain reaction (PCR). To produce the variants 49-53 and 65-78, a PCR-based approach of gene splicing by overlap extension was used. Recombinant cystatin proteins were produced as insoluble inclusion bodies as fusion proteins with a glutathione S-transferase (GST) carrier. After solubilization with urea the GST carrier was cleaved from the fusion protein with thrombin and cystatin variants purified by fast liquid chromatography on a MonoQ column. The purified proteins reacted with antibodies to rat salivary cystatin. The N-terminal truncated and variant 49-53 exhibited very little inhibitory activity towards papain, whereas variant 65-78 exhibited papain-inhibitory activity similar to the full-length recombinant cystatin.

Detection of the low density lipoprotein receptor gene PvuII intron 15 polymorphism using the polymerase chain reaction: association with plasma lipid traits in healthy men and women

We have used anchored PCR to amplify and sequence 1400 bp of the 15th intron of the Low Density Lipoprotein (LDL) receptor gene, and have determined oligonucleotides and conditions for the genotyping of the previously reported PvuII polymorphism. The cutting site (CAGCTG) is created by the transition of a CpG to a TpG within the sequence CAGCCG at a position roughly 600 bp 5' from the splice acceptor site of exon 16. Genotype was determined in three population-based samples of healthy individuals. In a group of 318 men and women from Iceland the frequencies of the Intron-15 T (cutting) allele was 0.23 (95% CI, 0.19-0.28) and was similar in men and women. In two groups of men from England (n = 385) and Scotland (n = 320), the frequency was similar, being 0.23 (0.19-0.27) and 0.25 (0.22-0.28) respectively. Individuals who were homozygous for the T allele had lower levels of total-cholesterol triglycerides and apolipoprotein B, than those with other genotypes, and in the combined group of UK men this effect reached statistical significance; compared to the C/C group, the T/T group had 6% lower cholesterol (p = 0.02) and 15% lower triglycerides (p = 0.03). The lowering effect associated with the T/T genotype was greater in men who were in the lowest tertile of body mass index (< 25 kg/m2) and for the trait of apoB levels, this genotype x obesity interaction was statistically significant (p = 0.01). We thus confirm the association between this allele and lower levels of plasma lipid levels previously reported. The availability of a PCR-based method to detect this polymorphism will facilitate further investigation of the impact of LDL-receptor gene variation in determining lipid levels.

Reduction of arthritis and pneumonitis in motheaten mice by soluble tumor necrosis factor receptor

OBJECTIVE

To determine the effects of anti-tumor necrosis factor (anti-TNF) therapy in the inflammatory and autoimmune disease in motheaten (me/me) mice, which exhibit a Fas apoptosis signaling defect.

METHODS

Arthritis, pneumonitis, and mortality were analyzed in me/me mice treated with a novel, soluble, dimeric TNF receptor I (sTNFRI) molecule capable of high-affinity binding and neutralization of TNFalpha.

RESULTS

Soluble TNFRI reduced serum levels of TNFalpha and led to a 2-fold increase in the lifespan of me/me mice, compared with the control treatment group. The treatment also reduced the development of the "motheaten" skin patches and alleviated pneumonitis and inflammatory lesions in the extremities of me/me mice compared with controls. However, the serum levels of IgM and IgM anti-double-stranded DNA autoantibody were comparable to those of untreated control mice.

CONCLUSION

TNFalpha is an important cytokine involved in the pathogenesis of inflammatory disease in me/me mice, resulting in tissue damage and early mortality. Therapies directed at blocking TNF/TNFR interactions, such as the sTNFRI used in these experiments, may be effective in diseases associated with apoptosis defects leading to overutilization of the TNF/TNFR pathway.

Metalloid resistance mechanisms in prokaryotes

Resistance to antibiotics and other chemotherapeutic agents is becoming a wide spread health issue. The biochemical mechanisms of resistance vary, but active efflux of the toxic agents is one of the most common. Bacterial resistances to metals provide good model systems for transport-related resistances. One of the best understood metal resistance systems is the product of the ars operon, which provides resistance to arsenicals and antimonials. As a reflection of the ubiquity of arsenic in the environment, ars operons are found in all species of bacteria, carried in chromosomes, plasmids, and transposons. This review focuses on the biochemistry of the proteins of the ars operon of R-factor R773. The system is novel in several respects. First, it is regulated at the transcriptional and allosteric levels, and regulation is effected through cysteine thiol interaction with As(III) or Sb(III). Thus soft metal-thiol chemistry provides a high affinity digital switch to turn the regulated protein on with rapidity. The transport system that provides resistance, on the other hand, uses oxyanions of arsenic or antimony as substrates. This nonmetal chemistry allows for low affinity interactions of the membrane transporter with substrate, conductive with translocation and release of substrate on the outside of the cell membrane. Second, the transporter is uniquely capable of coupling to either electrochemical energy as a secondary carrier protein or the chemical energy of ATP when binding of a catalytic subunit converts it into an anion-translocating ATPase.

Reduction of arthritis and pneumonitis in motheaten mice by soluble tumor necrosis factor receptor

OBJECTIVE

To determine the effects of anti-tumor necrosis factor (anti-TNF) therapy in the inflammatory and autoimmune disease in motheaten (me/me) mice, which exhibit a Fas apoptosis signaling defect.

METHODS

Arthritis, pneumonitis, and mortality were analyzed in me/me mice treated with a novel, soluble, dimeric TNF receptor I (sTNFRI) molecule capable of high-affinity binding and neutralization of TNFalpha.

RESULTS

Soluble TNFRI reduced serum levels of TNFalpha and led to a 2-fold increase in the lifespan of me/me mice, compared with the control treatment group. The treatment also reduced the development of the "motheaten" skin patches and alleviated pneumonitis and inflammatory lesions in the extremities of me/me mice compared with controls. However, the serum levels of IgM and IgM anti-double-stranded DNA autoantibody were comparable to those of untreated control mice.

CONCLUSION

TNFalpha is an important cytokine involved in the pathogenesis of inflammatory disease in me/me mice, resulting in tissue damage and early mortality. Therapies directed at blocking TNF/TNFR interactions, such as the sTNFRI used in these experiments, may be effective in diseases associated with apoptosis defects leading to overutilization of the TNF/TNFR pathway.

Cell death and longevity: implications of Fas-mediated apoptosis in T-cell senescence

Two prominent features of immune senescence are altered T-cell phenotype and reduced T-cell response. We have previously shown that T-cell senescence is greatly reduced in CD2-fas transgenic mice, in which the Fas apoptosis molecule is constantly expressed on T cells. Using a different experimental approach, the relationship between T-cell senescence and apoptosis was analyzed on human peripheral blood mononuclear cells. The results indicate that there was increased apoptosis of CD45RO- (CD45RA+) T cells upon activation. We propose that this could account for the increase in CD45RO+ "memory" T cells with aging in humans. T-cell responsiveness remained high in CD2-fas transgenic aged mice, but there was no increase in overall life span of these mice. Increased T-cell responsiveness was associated with an increased acute-phase response and serum amyloid A deposition in the glomerulus of aged CD2-fas transgenic mice. Therefore, restoration of the T-cell immune function using a CD2-fas transgene produced undesirable side-effects to aged transgenic mice. In addition to its role in activation-induced cell death, Fas-mediated apoptosis may be important in deleting T cells in response to DNA damage. It may also inhibit cell-cycle progression by cleaving various kinases and DNA repair enzymes. We observed that cell lines derived from human premature aging diseases have a higher sensitivity to Fas-mediated apoptosis. The implications of these observations are discussed.

[Study on the degradation kinetics of spiramycin in acid and alkaline solutions]

Physical and chemical characteristics of spiramycin (SPM) were reviewed in this paper. The degradation rule and kinetics of SPM in acid and alkaline solutions were studied, and the kinetic parameters were calculated. The experimental results showed that the stable range of SPM in water is at pH 4.0~10.0 Degradation occurred seriously at pH<4.0 and pH> 10.0, especially at pH< 2.8 and pH> 12.8. For this reason, the yield of SPM is greatly affected. The solubility in water was also studied by using reference data. The thermodynamical parameters were calculated. The results showed that the solution of SPM in water is exothermic. The solubility decreases as temperature rises.

Interleukin 9: a candidate gene for asthma

Asthma is a complex heritable inflammatory disorder of the airways associated with clinical signs of atopy and bronchial hyperresponsiveness. Recent studies localized a major gene for asthma to chromosome 5q31-q33 in humans. Thus, this segment of the genome represents a candidate region for genes that determine susceptibility to bronchial hyperresponsiveness and atopy in animal models. Homologs of candidate genes on human chromosome 5q31-q33 are found in four regions in the mouse genome, two on chromosome 18, and one each on chromosomes 11 and 13. We assessed bronchial responsiveness as a quantitative trait in mice and found it linked to chromosome 13. Interleukin 9 (IL-9) is located in the linked region and was analyzed as a gene candidate. The expression of IL-9 was markedly reduced in bronchial hyporesponsive mice, and the level of expression was determined by sequences within the qualitative trait locus (QTL). These data suggest a role for IL-9 in the complex pathogenesis of bronchial hyperresponsiveness as a risk factor for asthma.

Isoniazid-induced hepatic necrosis and steatosis in rabbits: absence of effect of gender

Isoniazid, a highly effective drug for the chemoprophylaxis and treatment of tuberculosis, is associated with severe hepatotoxicity in 1-2% of individuals. In a rabbit model of isoniazid-induced hepatotoxicity, we have measured hepatic necrosis (quantitated by elevation of plasma argininosuccinic acid lyase (ASAL) activity), hepatic steatosis (quantitated by elevation of hepatic triglyceride content), and elevation in plasma triglyceride concentration in 15 rabbits. Eight of 15 rabbits were male, and 14 of 15 were rapid acetylators of sulfamethazine. Administration of isoniazid to rabbits resulted in a 27-fold increase in plasma ASAL activities, a 7.5-fold increase in hepatic triglyceride content, and a 13-fold increase in plasma triglyceride levels. This study demonstrated no effect of gender on these three pathological changes that occur in this model of isoniazid-induced hepatotoxicity in rabbits.