[The relationship between postburn gene expression of modulators in gut associated lymph tissue and the change in IgA plasma cells]

OBJECTIVE

To investigate the relationship between the postburn change in IgA plasma cells and those of IL- 4 and IL-6 in gut associated lymph tissue (GALT).

METHODS

One hundred and twenty -- five SPF mice were enrolled in the study and randomly divided into three groups -- normal control (A), microbial inoculation (B) and microbial inoculation followed by burn injury. (C) In groups Band C, the mice were gavaged with candida albicans, and the mice in group C, were inflicted with 20% TBSA III degree burn at the 14th day after inoculation. The mice were sacrificed thereafter on 1, 2 and 3 postburn days and the samples were obtained aseptically. The number of candida albicans adhering to intestinal mucosal membrane was counted. The number of IgA plasma cells in lamina propria was determined by immunohistochemical staining. The gene expression of IL-4 in Peyer patch was detected by dothybridization and that of IL-6 in lamina propria was determined by insitu hybridization.

RESULTS

(1) The postburn gene expression of IL-4 in Peyer patch decreased, but the IL-6 level in intestinal lamina propria increased. (2) The number of IgA plasma cells in lamina propria decreased significantly, but the adherence of candida albicans to intestinal mucous membrane increased obviously.

CONCLUSION

The decrement of postburn gene expression of IL-4 in Peyer patch might lead to IgA plasma cell decrease, resulting in the increase of candida albicans adhering to intestinal mucosal membrane.

The yeast antiviral proteins Ski2p, Ski3p, and Ski8p exist as a complex in vivo

The yeast superkiller (SKI) genes were originally identified from mutations allowing increased production of killer toxin encoded by M "killer" virus, a satellite of the dsRNA virus L-A. XRN1 (SKI1) encodes a cytoplasmic 5'-exoribonuclease responsible for the majority of cytoplasmic RNA turnover, whereas SKI2, SKI3, and SKI8 are required for normal 3'-degradation of mRNA and for repression of translation of poly(A) minus RNA. Ski2p is a putative RNA helicase, Ski3p is a tetratricopeptide repeat (TPR) protein, and Ski8p contains five WD-40 (beta-transducin) repeats. An xrn1 mutation in combination with a ski2, ski3, or ski8 mutation is lethal, suggesting redundancy of function. Using functional epitope-tagged Ski2, Ski3, and Ski8 proteins, we show that Ski2p, Ski3p, and Ski8p can be coimmunoprecipitated as an apparent heterotrimeric complex. With epitope-tagged Ski2p, there was a 1:1:1 stoichiometry of the proteins in the complex. Ski2p did not associate with Ski3p in the absence of Ski8p, nor did Ski2p associate with Ski8p in the absence of Ski3p. However, the Ski3p/Ski8p interaction did not require Ski2p. In addition, ski6-2 or ski4-1 mutations or deletion of SKI7 did not affect complex formation. The identification of a complex composed of Ski2p, Ski3p, and Ski8p explains previous results showing phenotypic similarity between mutations in SKI2, SKI3, and SKI8. Indirect immunofluorescence of Ski3p and subcellular fractionation of Ski2p and Ski3p suggest that Ski2p and Ski3p are cytoplasmic. These data support the idea that Ski2p, Ski3p, and Ski8p function in the cytoplasm in a 3'-mRNA degradation pathway.

[Study of platelet membrane glycoproteins and its fibrinogen binding reaction in patients with cerebral infarction and diabetes mellitus]

OBJECTIVE

To investigate the change of platelet membrane glycoproteins and its fibrinogen binding reaction in patients with cerebral infarction and type II diabetes mellitus (DM), and assess their value in the study of thrombosis and pro-thrombosis state.

METHODS

By flow cytometry, the platelet glycoprotein (GP) I b, GP II b, GP III a, GP II b- III a complex and P-selectin expression as well as fibrinogen binding reaction were analyzed in 85 patients with type II DM and 28 with cerebral infarction, and compared with that in 30 normal subjects.

RESULTS

The platelet membrane GP II b- III a complex, P-selectin expression and fibrinogen binding reaction were higher, while the platelet surface GP I b was lower in the patients with cerebral infarction and type II DM with vascular disease than those in normal group. The GP II b and GP III a were not significantly changed. There was no difference of these parameters between the type II DM without vascular disease patients and normal group.

CONCLUSION

The platelet fibrinogen binding reaction, P-selectin and GP II b- III a complex expression were increased while the GP I b decreased in patients with cerebral infarction and type II DM with vascular disease.

[Changes in myelin sheath and axon of spinal cord in X-irradiation injured rats]

OBJECTIVE

To investigate the X-irradiation effect on the myelin sheath and axon of the spinal cord.

METHODS

60 Wistar adult rats receiving hemisection in the thoracic spinal cord were made into models of spinal injury. Among these rats, 30 in the test group received X-irradiation of 35-Gy the day after operation, while 30 in the control group only received hemisection. Operative spinal cord was subjected to immunohistochemistry and hyper-microscopic observation.

RESULTS

In the test group, injury to the myelin sheath of the upper and lower lesion and the number of neuro-fibrotic positive axon increased. In the control group the number of myelin sheath below the injured section decreased. Under electronic microscope, demyelination was found in the spinal cord and new-born tiny neuro-fibrotic tracts were seen below the lesion.

CONCLUSIONS

X-irradiation can make spinal cord demyelinate and promote the increase of neuro-fibrotic positive axon.

Clinical and biochemical characteristics of growth hormone-secreting pituitary tumors

To investigate the difference of biochemical characteristics on gsp-positive and gsp-negative growth hormone (GH)-secreting pituitary tumors, 18 GH-secreting pituitary tumors were examined for their clinical characteristics and gsp oncogenes. All patients received the pituitary function combinative stimulating test. It was found that there were no difference in the sex, age, tumor size, course of disease and plasma basal GH levels with gsp-positive and gsp-negative patients. The plasma levels of PRL were increased in most patients (11/18), and the plasma levels of TSH in gsp-positive patients were higher than those in gsp-negative patients (P < 0.05). There was no significant difference in the responses to pituitary combinative stimulating test in gsp-positive and gsp-negative patients. It was concluded that there was little difference in the clinical biochemical characteristics of gsp-positive with gsp-negative GH-secreting pituitary tumors.

The role of protein kinase C and its effect on GHRH in the regulation of hormone secretion by somatotrophinomas

Phorbol ester-induced release of growth hormone (GH) and prolactin (PRL) from human somatotrophic tumors was examined in vitro. 12-O-tetradecanoyl-phorbol-13-acetate (TPA) strongly stimulated GH and PRL secretion and showed an additive effect on GH secretion if used in combination with GH releasing hormone (GHRH). In contrast, staurosporine exerted a variable inhibitory effect on GH release. There was no correlation between such effects and gsp mutations. The findings suggested that TPA doesn't act directly through cAMP signal transduction system.

Inactivation of p16 gene in leukemia

To determine the frequency of p16 gene inactivation in leukemia cells, and to evaluate their value in the prediction of their clinical outcome. Bone marrow or peripheral blood samples from 48 patients with leukemia were examined by multiplex polymerase chain reaction (MPCR) to detect p16 gene homozygous deletion, and restriction enzyme PCR to detect p16 gene methylation. p16 gene inactivation were detected in 10 of the 48 patients (20.4%). They were five patients with p16 homozygous deletion, and five patients with p16 methylation, respectively. p16 gene inactivation correlates with adverse prognosis features. The patients with p16 inactivation had poor response to chemotherapy, and had significantly shorter survival times than the patients in whom p16 gene was preserved (P<0.001). The inactivation of p16 gene play a key role in the pathogenesis and the progression of some leukemia. The detection of p16 gene is reliable prognostic factor that predict shortened survival times.

Asymmetric synthesis of 9-alkyl-2-benzyl-6,7-benzomorphans: characterization as novel sigma receptor ligands

A convenient enantioselective synthesis of (1R,5R,9R)- and (1S,5S, 9S)-9-alkyl-2-benzyl-6,7-benzomorphans (2a-c) which starts with naphthaldehyde is described. These compounds were designed to gain additional information on the structure-sigma binding relationship of the 6,7-benzomorphan class of sigma ligands. In contrast to pentazocine and most 6,7-benzomorphans, the (1R,5R,9R)-isomers of 2a-c showed greater affinity for the sigma(1) receptor than the (1S, 5S,9S)-isomers. Despite reversal of enantioselectivity at the sigma(1) sites, moderate affinity and enantioselectivity at the sigma(2) sites [greater affinity for (1R,5R,9R)-isomers than (1S,5S, 9S)-isomers] were maintained. A comparison of the binding affinities of 2a-c to the more conformationally flexible trans-2-alkyl-1-benzaminoethyl-1,2-dihydronaphthalenes (10a-c) suggested that the relatively rigid structure of 2a-c played an important part in their sigma(1) binding properties. These compounds, particularly (1R,5R,9R)-2-benzyl-9-methyl-6,7-benzomorphan [(-)-2a], which has a K(i) value of 0.96 nM, will be useful in further characterization of the sigma(1) receptor.

[Effects of high fluoride intake on the fluoride of femora, teeth and some biochemical indexes in rats]

In order to approach practicable indexes for assessing the effects of the products which are intended to be used to prevent endemic fluorosis, Wistar rats were fed with fluoridated water(50 mg/L) for four weeks. After only one week treated with fluoride, a higher activity of NAG(N-acetyl-beta-D-glucosaminidase) in urine, ChE(cholinesterase) in blood and increased urinary excretion of fluoride (compared with the control, P < 0.01) were observed, and these changes were lasted to the end of the fourth week of the study, but hydroxyproline in serum and urine had not been changed in both groups. After four weeks, the fluoride levels in the femora and teeth of fluoride treated group were ten times higher than that of the control group. According to the results, fluoride in bones and teeth must be taken as key indexes, the activities of NAG in urine and ChE in blood should be taken into consideration for assessing the effects of fluoride protagonist.

Determination of free calcium in guinea-pig cochlea perilymph by capillary electrophoresis with direct injection

At present, the tinnitus mechanism is still not clear. Our experiments demonstrated that the concentration of free calcium in cochlea perilymph of tinnitus model guinea-pigs is lower than that in normal guinea-pigs. However, the volume of cochlea perilymph is so small that only 5-10 microL of sample can be obtained from each animal. We describe the application of CE to the detection of free calcium in guinea-pig cochlea perilymph. Direct injection was employed in this study. The separation was carried out at 10 kV. The capillary temperature was maintained at 20 degrees C, and indirect UV detection at 214 nm was employed. The samples were vacuum injected for 3 s. The run buffer was 0.005 mol/L imidazole with a pH of 4.30-4.50. The concentration of free calcium in the normal group was found to be in accordance with the reference data. The method has been applied to research on the tinnitus mechanism and for medical treatment.

A novel role for 3-O-sulfated heparan sulfate in herpes simplex virus 1 entry

Herpes simplex virus type 1 (HSV-1) binds to cells through interactions of viral glycoproteins gB and gC with heparan sulfate chains on cell surface proteoglycans. This binding is not sufficient for viral entry, which requires fusion between the viral envelope and cell membrane. Here, we show that heparan sulfate modified by a subset of the multiple D-glucosaminyl 3-O-sulfotransferase isoforms provides sites for the binding of a third viral glycoprotein, gD, and for initiation of HSV-1 entry. We conclude that susceptibility of cells to HSV-1 entry depends on (1) presence of heparan sulfate chains to which virus can bind and (2) 3-O-sulfation of specific glucosamine residues in heparan sulfate to generate gD-binding sites or the expression of other previously identified gD-binding receptors.

The URA5 gene encoding orotate-phosphoribosyl transferase of the yeast Kluyveromyces lactis: cloning, sequencing and use as a selectable marker

A pair of degenerate primers was used for amplification and cloning of an internal fragment of the K. lactis URA5 gene. Primers were designed on the basis of highly conserved motifs within protein sequences predicted for URA5 genes from several microorganisms. Using the amplified fragment as a probe, we finally cloned and sequenced a 1.9 kb chromosomal fragment containing the orotate-phosphoribosyltransferase-encoding URA5 gene and an incomplete open reading frame strikingly similar to SEC65 of Saccharomyces cerevisiae and other yeasts, in which the gene encodes a subunit of the signal recognition particle. Uracil-requiring mutants of K. lactis CBS 683 were selected on media containing 5-fluoro-orotic acid and used as recipients in transformation experiments using K. lactis URA5 as the selectable marker, thereby proving functionality of the cloned gene.

The human uniqueness of HIV: innate immunity and the viral Tat protein

We have previously reported, and confirm here, that the human innate system of natural antibodies includes two, each of which is reactive, presumably by happenstance, with a specific sequence of HIV Tat protein. Comparison of cohorts of HIV+ and normal (HIV-) sera indicate that, following a period of post-infection latency, the titers of those natural antibodies decline and other Tat reactive antibodies, as evidence of induced immune response, do not arise. That human-typical pattern of innate/adaptive reactivity with HIV Tat protein is shared by chimpanzees, but not by other mammals tested in this study, in which those natural antibodies are not present, and apparently induced Tat-reactive antibodies do arise. Evidence of a temporal relationship between the decline of the Tat reactive natural antibodies and progression of HIV pathogenesis, including demise of CD4+T cells, suggests a role for those antibodies in retardation of that pathoprogression. However, that providential arrest of Tat-related pathogenicity may be limited by the immune system recognition of the natural antibody-reactive sequences of Tat as "self" with consequent induction of tolerance and restriction of production of those antibodies. The limited occurrence of progression to AIDS in chimpanzees may reflect an additional innate characteristic, one of resistance to tolerance-based diminishment of the protective natural antibodies. Although not yet defined, that characteristic may be shared by the occasionally observed HIV+ humans known as LTNP (longterm-non-progressors).

Mechanisms of nasal tolerance induction in experimental autoimmune myasthenia gravis: identification of regulatory cells

Autoantigen administration via nasal mucosal tissue can induce systemic tolerance more effectively than oral administration in a number of experimental autoimmune diseases, including Ab-mediated experimental autoimmune myasthenia gravis, a murine model of myasthenia gravis. The mechanisms underlying nasal tolerance induction are not clear. In this study, we show that nasal administration of acetylcholine receptor (AChR) in C57BL/6 mice, before immunizations with AChR in adjuvant, results in delayed onset and reduced muscle weakness compared with control mice. The delayed onset and reduced muscle weakness were associated with decreased AChR-specific lymphocyte proliferation and decreased levels of anti-AChR Abs of the IgG2a and IgG2b isotypes in serum. The clinical and immunological changes in the AChR-pretreated C57BL/6 wild-type (wt) mice were comparable with those observed in AChR-pretreated CD8-/- mice, indicating that CD8+ T cells were not required for the generation of nasal tolerance. AChR-pretreated wt and CD8-/- mice showed augmented TGF-beta and reduced IFN-gamma responses, whereas levels of IL-4 were unaltered. Splenocytes from AChR-pretreated wt and CD8-/- mice, but not from CD4-/- mice, suppressed AChR-specific lymphocyte proliferation. This suppression could be blocked by Abs against TGF-beta. Thus, our results demonstrate that the suppression induced in the present model is independent of CD8+ T cells and suggest the involvement of Ag-specific CD4+ Th3 cells producing TGF-beta.

Chinese hamster ovary cell mutants defective in glycosaminoglycan assembly and glucuronosyltransferase I

The proteoglycans of animal cells typically contain one or more heparan sulfate or chondroitin sulfate chains. These glycosaminoglycans assemble on a tetrasaccharide primer, -GlcAbeta1, 3Galbeta1,3Galbeta1,4Xylbeta-O-, attached to specific serine residues in the core protein. Studies of Chinese hamster ovary cell mutants defective in the first or second enzymes of the pathway (xylosyltransferase and galactosyltransferase I) show that the assembly of the primer occurs by sequential transfer of single monosaccharide residues from the corresponding high energy nucleotide sugar donor to the non-reducing end of the growing chain. In order to study the other reactions involved in linkage tetrasaccharide assembly, we have devised a powerful selection method based on induced resistance to a mitotoxin composed of basic fibroblast growth factor-saporin. One class of mutants does not incorporate 35SO4 and [6-3H]GlcN into glycosaminoglycan chains. Incubation of these cells with naphthol-beta-D-xyloside (Xylbeta-O-Np) resulted in accumulation of linkage region intermediates containing 1 or 2 mol of galactose (Galbeta1, 4Xylbeta-O-Np and Galbeta1, 3Galbeta1, 4Xylbeta-O-Np) and sialic acid (Siaalpha2,3Galbeta1, 3Galbeta1, 4Xylbeta-O-Np) but not any GlcA-containing oligosaccharides. Extracts of the mutants completely lacked UDP-glucuronic acid:Galbeta1,3Gal-R glucuronosyltransferase (GlcAT-I) activity, as measured by the transfer of GlcA from UDP-GlcA to Galbeta1,3Galbeta-O-naphthalenemethanol (<0.2 versus 3.6 pmol/min/mg). The mutation most likely lies in the structural gene encoding GlcAT-I since transfection of the mutant with a cDNA for GlcAT-I completely restored enzyme activity and glycosaminoglycan synthesis. These findings suggest that a single GlcAT effects the biosynthesis of common linkage region of both heparan sulfate and chondroitin sulfate in Chinese hamster ovary cells.

Development and validation of a quantitative polymerase chain reaction assay to evaluate minimal residual disease for T-cell acute lymphoblastic leukemia and follicular lymphoma

The presence of occult disease in cancer patients after therapy is one of the major problems faced by oncologists. For example, although 95% of pediatric T-cell acute lymphoblastic leukemia (T-ALL) patients have a complete therapeutic response to multiagent chemotherapy, half will relapse, indicating that they must have harbored low levels of residual cancer cells at the end of therapy. Sensitive detection assays promise to help identify those patients that carry this minimal residual disease (MRD) and are at risk of relapse. We have developed and validated a quantitative polymerase chain reaction (PCR) assay targeting tumor-specific chromosomal rearrangements, including del(1) involving the tal-1 locus in pediatric T-ALL and t(14;18) involving the bcl-2 locus in follicular lymphoma. This quantitative PCR assay utilizes a synthetic internal calibration standard (ICS) that contains priming sequences identical to those found flanking the chromosomal rearrangement breakpoints. Using this ICS-PCR method, the limits of detection were 5 tumor cells at ratios of 1 tumor cell in 10(5) normal cells and a linear range up to 100% tumor cells. This ICS-PCR method has also performed well in terms of precision and accuracy as indicated by low coefficients of variation, minimal random, proportional, and constant errors, and good clinical sensitivity and specificity characteristics. This technique will allow for the evaluation of parameters such as the rate of therapeutic response and the levels of MRD as predictors of patient outcome.

[Distribution of lead in fetal rat tissue at different days of pregnancy]

In order to reveal the mechanism of the transplacental transfer of lead from mothers to fetus, tissues lead content of fetal rat at different days of pregnancy were determined and compared. Lead was administered to four groups of 4 week-old female Wistar rats for 50 days. The doses of lead were 0, 10, 50 and 200 mg/L in drinking water respectively. Rats were mated with non-lead-treated male rats. The pregnant rats in each group were then divided into four sub-groups by random. The pregnant rats in four sub-group of each group were sacrificed in turn at 10, 14, 17 and 20 days of gestation (dg). Blood lead of pregnant rats, lead burden of whole fetus, lead concentration of fetal brain, fetal liver and placenta were determined. Results indicated that lead concentration in fetal brain kept unchanged during the period of gestation, but lead content in whole fetus and fetal brain were increased with the days of gestation. But the lead concentration in fetus at 10 dg was higher than that at 14 dg. It seemed that higher lead absorption by the fetus was related to the newly emerged lead bonding-site in fetus, especially during the calcification of bones.

Formation of HNK-1 determinants and the glycosaminoglycan tetrasaccharide linkage region by UDP-GlcUA:Galactose beta1, 3-glucuronosyltransferases

While expression-cloning enzymes involved in heparan sulfate biosynthesis, we isolated a cDNA that encodes a protein 65% identical to the UDP-GlcUA:glycoprotein beta1, 3-glucuronosyltransferase (GlcUAT-P) involved in forming HNK-1 carbohydrate epitopes (3OSO3GlcUAbeta1,3Gal-) on glycoproteins. The cDNA contains an open reading frame coding for a protein of 335 amino acids with a predicted type II transmembrane protein orientation. Cotransfection of the cDNA with HNK-1 3-O-sulfotransferase produced HNK-1 carbohydrate epitopes in Chinese hamster ovary (CHO) cells and COS-7 cells. In vitro, a soluble recombinant form of the enzyme transferred GlcUA in beta-linkage to Galbeta1,3/4GlcNAcbeta-O-naphthalenemethanol, which resembles the core oligosaccharide on which the HNK-1 epitope is assembled. However, the enzyme greatly preferred Galbeta1, 3Galbeta-O-naphthalenemethanol, a disaccharide component found in the linkage region tetrasaccharide in chondroitin sulfate and heparan sulfate. During the course of this study, a human cDNA clone was described that was thought to encode UDP-GlcUA:Galbeta1,3Gal-R glucuronosyltransferase (GlcUAT-I), involved in the formation of the linkage region of glycosaminoglycans (Kitagawa, H., Tone, Y., Tamura, J., Neumann, K. W., Ogawa, T., Oka, S., Kawasaki, T., and Sugahara, K. (1998) J. Biol. Chem. 273, 6615-6618). The deduced amino acid sequences of the CHO and human cDNAs are 95% identical, suggesting that they are in fact homologues of the same gene. Transfection of a CHO cell mutant defective in GlcUAT-I with the hamster cDNA restored glycosaminoglycan assembly in vivo, confirming its identity. Interestingly, transfection of the mutant with GlcUAT-P also restored glycosaminoglycan synthesis. Thus, both GlcUAT-P and GlcUAT-I have overlapping substrate specificities. However, the expression of the two genes was entirely different, with GlcUAT-I expressed in all tissues tested and GlcUAT-P expressed only in brain. These findings suggest that, in neural tissues, GlcUAT-P may participate in both HNK-1 and glycosaminoglycan production.

Isolation and characterization of SYN1, a RAD21-like gene essential for meiosis in Arabidopsis

The proper pairing, recombination, and segregation of chromosomes are central to meiosis and sexual reproduction. The syn1 mutation was previously identified as a synaptic mutant in a T-DNA-tagged population of plants. SYN1 has been isolated and found to exhibit similarity to Schizosaccharomyces pombe RAD21 and RAD21-like proteins, which are required for chromosome condensation and sister chromatid cohesion during mitosis. Plants homozygous for syn1 are male and female sterile and show defects in chromosome condensation and pairing beginning at leptonema of meiosis I. Fragmentation of the chromosomes was observed at metaphase I. Alternative promoters produced two SYN1 transcripts. One transcript was expressed at low levels in most tissues, whereas the other was expressed only in prebolting buds. DNA blot analyses suggest that Arabidopsis contains a small RAD21 gene family. Consistent with the DNA blot data, a second Arabidopsis RAD21-like gene has been identified. These results suggest that different RAD21-like proteins play essential roles in chromosome condensation and pairing during both meiosis and mitosis.

TPA enhances growth hormone (GH) secretion effect of GH-releasing hormone (GHRH) by human gsp-positive pituitary somatotrophinomas

In recent years, one of the most exciting advances in the researches of pituitary adenomas is the discovery that 30%-40% of human pituitary somatotrophinomas carry somatic mutations of the gene for the alpha-subunit of the stimulatory GTP-binding protein, Gs (Gs alpha). These mutations, termed gsp oncogenes, may play an important role in the tumorigenesis of pituitary adenomas. Of 10 somatotrophinomas examined, 3 (30%) were proved to be gsp positive, as determined by sequence analysis of DNA generated by the polymerase chain reaction (PCR). GHRH exerted a significant stimulatory effect on GH secretion in 2 of 3 gsp-positive and 4 of 7 gsp-negative tumors. Moreover, phorbol ester, 1, 2-tetradecanoylphorbol-13-acetate (TPA), enhanced stimulation of lated the GH secretion effect exerted by GHRH in gsp-positive somatotrophinomas, whereas this effect was not observed in gsp-negative tumors. This result suggests that the protein kinase C signal system as well as adenylyl cyclase-cAMP-protein kinase A intracellular signal transduction system plays a pivotal role in GH secretory control of GHRH, which may work together via a cross-talk mechanism.

The effect of GHRH, GHRP-2 and somatostatin on GH secretion by fetal pituitary

Growth hormone releasing peptide (GHRP-2) is a synthetic hexapeptide which specifically stimulates secretion of growth hormone (GH) by fetal pituitary somatotrophs through a new membrane receptor, which is different from growth hormone releasing hormone (GHRH) and somatostatin (SMS) receptors. We used cell cultures of human fetal pituitary somatotroph cells to investigate the effect of GHRH, GHRP-2 and somatostatin on GH secretion. The results showed that the mechanism of GHRH/SMS and GHRP-2 was different. This indicated that a different intracellular signal transduction system might also play a crucial role in the regulation of GH secretion.

Effects of the novel GH secretogogue, hexarelin on GH secretion and phosphatidylinositol hydrolysis by human pituitary somatotrophinomas in cell culture

The effects of the novel GH-releasing hexapeptide, Hexarelin, on cultured human pituitary somatotrophinomas were investigated. Hexarelin (0.01-100 nmol/L) dose-dependently stimulated GH secretion up to 4.6-fold. Maximal effects occurred with 10 nmol/L. These effects were very similar to those observed with GHRP-6. The effects of Hexarelin were reduced by phloretin, an inhibitor of protein kinase C (PKC). The rate of phosphatidylinositol (PI) hydrolysis was markedly increased by Hexarelin in a dose-dependent manner. These results demonstrated that Hexarelin could directly stimulate GH secretion by human pituitary somatotrophs in a PKC-dependent manner, probably via activation of the PI transduction system.

[Correlation between shape and direction of small articular surface in lower lumbar vertebrae and degeneration of intervertebral disc]

To assess the possible correlation between the shape and the direction of the small articular surface in the lower lumbar vertebrae and the degeneration of the intervertebral disc, we investigated with computed tomography (CT) and evaluated with statistics the small articular surface and the transverse interface-joint angle (TIFA) of the L4-5 and the L5-S1 in 152 cases who had normal or degenerative discs verified through CT, MRI or operation. The small articular surface was found arc in 69.1% of the L4-5 and in 23.0% of the L5-S1. The TIFA of the L4-5 was less than that of the L5-S1. There was no correlation between the ratio of degeneration of the intervertebral disc at the L4-5 and the TIFA of the L4-5 and the L5-S1, but the ratio of degeneration of the intervertebral disc at the L5-S1 had postive correlation with the TIFA of the L4-5, negative correlation with the TIFA of the L5-S1, and particular correlation with the TIFA of the L5-S1 and L4-5. These results suggest that the shape and direction of the lower lumbar facet joint are related to the lumbar degeneration of intervertebral disc and the causes of degeneration at the L4-5 disc differ from those at the L5-S1 disc in biomechanics.

Cytokine and chemokine mRNA expressing cells in muscle tissues of experimental autoimmune myasthenia gravis

In-situ hybridization with labeled oligonucleotide probes was applied to explore cytokine and chemokine mRNA expression in sections of striated muscle, the target organ in experimental autoimmune myasthenia gravis (EAMG), induced in Lewis rats by immunization with acetylcholine receptor (AChR) and complete Freund's adjuvant (CFA). A transient burst of TNF-alpha, IL-1beta and IL-6 mRNA expressing cells was detected during the early phase of EAMG. This cytokine pattern was related to muscular infiltration of macrophages. Levels of IL-4, IL-10, IFN-gamma, cytolysin and TGF-beta mRNA expressing cells were low and observed mainly during the early phase of EAMG. C-C chemokine RANTES, MCP, MIP-1alpha and MIP-2 mRNA expressing cells were not detected over the course of EAMG. The low and transient expression of cytokines in EAMG muscle tissues suggests that the immune effector responses are unlikely operated by infiltrating cells in muscle. Muscular infiltrations in EAMG are unlikely due to local accumulation of C-C chemokines.

Conformationally constrained inhibitors of caspase-1 (interleukin-1 beta converting enzyme) and of the human CED-3 homologue caspase-3 (CPP32, apopain)

A systematic study of interleukin-1 beta converting enzyme (ICE, caspase-1) and caspase-3 (CPP32, apopain) inhibitors incorporating a P2-P3 conformationally constrained dipeptide mimetic is reported. Depending on the nature of the P4 substituent, highly selective inhibitors of both Csp-1 or Csp-3 were obtained.

[Enzymatic synthesis of cephradine]

Cephradine was synthesized by gamma-alumina-immobilized form of the penicillin G acylase of Bacillus megaterium with D-phenyglycine methylester hydrochloride (CH DGME.HCl) as acyl donor and 7-aminodeacetoxycephalosporanic acid (7-ADCA) as acyl acceptor. 0.1 g of 7-ADCA was dissolved by adding 2.5 ml of distilled water and about 0.25 ml of 2 mol/L NaOH in a 25 ml flask. To the solution, after 0.25 g of CHDGME.HCl was added, 0.1 mol/L phosphate-0.05 mol/L citric acid buffer, pH 7.5 was added to result in a volume of 5 ml with pH 7.5 Then 1 g(220 IU) of immobilized enzyme was added. The flask was shaken on a rotary shaker at 110 r/min and 25 degrees C for 5 h. The conversion rate of 7-ADCA was 81%. In an expanded experiment in 500 ml of reactive volume, 11.8 g of cephradine was obtained from 10 g of 7-ADCA. The conversion rate of 7-ADCA was 80% with about 87% yield of cephradine. Enzymatic synthesis was inhibited in varying degrees by phenylacetic acid, phenoxyacetic acid and cephalosporin G.

Genetic co-inactivation of macrophage- and T-tropic HIV-1 chemokine coreceptors CCR-5 and CXCR-4 by intrakines

CC-chemokine receptor (CCR)-5 is the principal coreceptor for the entry of macrophage (M)-tropic HIV-1 viruses into a cell, while CXC-chemokine receptor (CXCR)-4 is the principal coreceptor for T cell line (T)-tropic HIV-1. In this study, we utilized a novel intracellular chemokine (intrakine) strategy to co-inactivate genetically both CCR-5 and CXCR-4 in human lymphocytes. The principle of co-inactivation of CCR-5 and CXCR-4 was illustrated by targeting the CC-intrakine and CXC-intrakine to the lumen of the endoplasmic reticulum (ER) for intracellular blockade of the transport of newly synthesized chemokine coreceptors to the cell surface. The lymphocytes with the phenotypic knock-out of CCR-5 and CXCR-4 were found broadly to resist the infection of M-tropic, T-tropic and dual-tropic HIV-1 viruses. Moreover, the transduced lymphocytes retained normal cell features, including the responsiveness to mitogen and recall antigen stimulation. Thus, this study to our knowledge, is the first to demonstrate that genetic co-inactivation of the M- and T-tropic HIV-1 principal coreceptors in lymphocytes or other cells could be a viable strategy for the long-term control of HIV-1 infection.

[Mechanism of coronary vasodilation in myocardial regional hypoxia]

OBJECTIVE

To determine if coronary vasodilation is dependent upon adrenergic activation during myocardial regional.

METHODS

Studies were conducted in 10 Mongrel dogs of either sexes, in which LAD was perfused with normoxic (CAO2 = 18.4-20.4 ml/100 ml) or regional hypoxic (CAO2 = 7.8-8.1 ml/100 ml) blood with coronary perfusion system by self-control methods.

RESULTS

No significant differences were observed in hemodynamic values with regional hypoxia compared with normoxia before adrenergic receptor blocker was given, but coronary blood flow increased by 225%. There were significant differences in dp/dt max, dp/dt min after adrenergic blocker was given. Whether there was regional hypoxia or not, coronary blood flow still increased by 190%.

CONCLUSION

Coronary vasodilation is independent upon adrenergic activation during myocardial regional hypoxia.

Superantigen-activated T cells redirected by a bispecific antibody inhibit vesicular stomatitis virus replication in vitro and in vivo

A bispecific Ab (BsAb) that binds the TCR on T cells and the G protein of the vesicular stomatitis virus (VSV) can redirect staphylococcal enterotoxin B (SEB)-activated T cells to kill VSV-infected cells and to inhibit VSV replication in vitro. Inhibition of virus replication in our system is dependent upon the specificity of the Ab for the viral protein. IFN-gamma does not play a very important role in this phenomenon, which is mainly mediated by the release of Pfp from CD8+ T cells. We have used a Stat1 knockout mouse model in which VSV infection is lethal. Infusion of staphylococcal enterotoxin-activated B T cells and bispecific Ab significantly slowed virus progression and prolonged the survival of VSV-infected Stat1 knockout mice in vivo.

Hormone secretion by cell culture of human GH-PRL secreting pituitary adenomas: effects of bromocriptine

Dopamine agonists effectively reduce the secretion of prolactin (PRL) in the great majority of prolactinomas and reduce the bulk of the adenomas, as well as have partial therapeutic effect on some patients with acromegaly. The inhibitory effect of bromocriptine (BC), a dopamine agonist, on growth hormone (GH) and PRL secretion of dispersed cells from the pituitary adenomas of 16 cases of acromegaly, which secret GH and PRL simultaneously, were evaluated in vitro. The significant inhibitory effects of BC on PRL secretion were found in 12 cases. It was also found that PRL secretion was strongly inhibited when GH was suppressed; on the contrary, when GH secretion was not suppressed, the production of PRL was not or weakly inhibited. The exact mechanism of the effects is unclear so far. It is necessary to investigate, at molecular level, the etiology of GH-PRL adenomas and its response to therapeutic agents.

Adenylyl cyclase 6 is selectively regulated by protein kinase A phosphorylation in a region involved in Galphas stimulation

Receptors activate adenylyl cyclases through the Galphas subunit. Previous studies from our laboratory have shown in certain cell types that express adenylyl cyclase 6 (AC6), heterologous desensitization included reduction of the capability of adenylyl cyclases to be stimulated by Galphas. Here we further analyze protein kinase A (PKA) effects on adenylyl cyclases. PKA treatment of recombinant AC6 in insect cell membranes results in a selective loss of stimulation by high (>10 nM) concentrations of Galphas. Similar treatment of AC1 or AC2 did not affect Galphas stimulation. Conversion of Ser-674 in AC6 to an Ala blocks PKA phosphorylation and PKA-mediated loss of Galphas stimulation. A peptide encoding the region 660-682 of AC6 blocks stimulation of AC6 and AC2 by high concentrations of Galphas. Substitution of Ser-674 to Asp in the peptide renders the peptide ineffective, indicating that the region 660-682 of AC6 is involved in regulation of signal transfer from Galphas. This region contains a conserved motif present in most adenylyl cyclases; however, the PKA phosphorylation site is unique to members of the AC6 family. These observations suggest a mechanism of how isoform selective regulatory diversity can be obtained within conserved regions involved in signal communication.

Phenotypic knockout of HIV type 1 chemokine coreceptor CCR-5 by intrakines as potential therapeutic approach for HIV-1 infection

A genetic defect in a CC-chemokine receptor (CCR)-5, the principal coreceptor for the macrophage-tropic HIV type 1 (HIV-1), recently was found to naturally protect CCR-5-defective, but healthy, individuals from HIV-1 infection. In this study, we mimic the natural resistance of the CCR-5-defective individuals by designing a strategy to phenotypically knock out CCR-5. The inactivation of the CCR-5 coreceptor is accomplished by targeting a modified CC-chemokine to the endoplasmic reticulum to block the surface expression of newly synthesized CCR-5. The lymphocytes transduced to express the intracellular chemokine, termed "intrakine," were found to be viable and resistant to macrophage-tropic HIV-1 infection. Thus, this gene-based intrakine strategy targeted at the conserved cellular receptor for the prevention of HIV-1 entry should have significant advantages over currently described approaches for HIV-1 therapy.

Quantitative polymerase chain reaction for human herpesvirus diagnosis and measurement of Epstein-Barr virus burden in posttransplant lymphoproliferative disorder

Human herpesviruses can cause acute diseases such as chicken pox or mononucleosis, but also may reactivate during immunosuppression and result in severe or life-threatening illnesses such as shingles or lymphoproliferative disorders. We report the development and validation of a quantitative PCR method to measure viral burden for all eight human herpesviruses (HSV1, HSV2, VZV, EBV, CMV, HHV6, HHV7, and KSHV) in patients' samples. The method uses an internal standard that is coamplified with the viral target, allowing quantification of viral genomes in absolute terms (e.g., viral targets/mL of blood) and ruling out false-negative results. We demonstrate that transplant patients with lymphoproliferative disorder carry an EBV viral burden 3 logs higher than nontransplant patients. EBV titers in transplant patients without a lymphoproliferative disorder are between these values. This quantitative PCR method may aid in differentiating clinically significant vs latent viral burden in immunosuppressed patients.

Inactivation of HIV-1 chemokine co-receptor CXCR-4 by a novel intrakine strategy

CXC-chemokine receptor (CXCR)-4/fusin, a newly discovered co-receptor for T-cell line (T)-tropic HIV-1 virus, plays a critical role in T-tropic virus fusion and entry into permissive cells. The occurrence of T-tropic HIV viruses is associated with CD4-positive cell decline and progression to AIDS, suggesting that the T-tropic HIV-1 contributes to AIDS pathogenesis. In this study, we used a novel strategy to inactivate CXCR-4 by targeting a modified CXC-chemokine to the endoplasmic reticulum (ER) to block the surface expression of newly synthesized CXCR-4. The genetically modified lymphocytes expressing this intracellular chemokine, termed "intrakine", are immune to T-tropic virus infection and appear to retain normal biological features. Thus, this genetic intrakine strategy is uniquely targeted at the conserved cellular receptor for the prevention of HIV-1 entry and may be developed into an effective treatment for HIV-1 infection and AIDS.

Turnover of heparan sulfate depends on 2-O-sulfation of uronic acids

To study how the pattern of sulfation along a heparan sulfate chain affects its turnover, we examined heparan sulfate catabolism in wild-type Chinese hamster ovary cells and mutant pgsF-17, defective in 2-O-sulfation of uronic acid residues (Bai, X., and Esko, J. D. (1996) J. Biol. Chem. 271, 17711-17717). Heparan sulfate from the mutant contains normal amounts of 6-O-sulfated glucosamine residues and iduronic acid and somewhat higher levels of N-sulfated glucosamine residues but lacks any 2-O-sulfated iduronic or glucuronic acid residues. Pulse-chase experiments showed that both mutant and wild-type cells transport newly synthesized heparan sulfate proteoglycans to the plasma membrane, where they shed into the medium or move into the cell through endocytosis. Internalization of the cell-associated molecules leads to sequential endoglycosidase (heparanase) fragmentation of the chains and eventual lysosomal degradation. In wild-type cells, the chains begin to degrade within 1 h, leading to the accumulation of intermediate (10-20-kDa) and small (4-7-kDa) oligosaccharides. Mutant cells did not generate these intermediates, although internalization and intracellular trafficking of the heparan sulfate chains appeared normal, and the chains degraded with normal kinetics. This difference was not due to defective heparanase activities in the mutant, since cytoplasmic extracts from mutant cells cleaved wild-type heparan sulfate chains in vitro. Instead, the heparan sulfate chains from the mutant were relatively resistant to degradation by cellular heparanases. These findings suggest that 2-O-sulfated iduronic acid residues in heparan sulfate are important for cleavage by endogenous heparanases but not for the overall catabolism of the chains.

Cell adhesion to a motif shared by the malaria circumsporozoite protein and thrombospondin is mediated by its glycosaminoglycan-binding region and not by CSVTCG

The malaria circumsporozoite protein (CS), thrombospondin (TSP), and several other proteins including the terminal complement proteins and the neural adhesion molecules F-spondin and Unc-5, share a cell adhesive sequence. In CS this sequence is designated as region II-plus (EWSPCSVTCGNGIQVRIK) and in TSP it is found in the type I repeats. Previous studies aimed at fine mapping the amino acid residues required for cell adhesion have yielded discrepant results. Here we show in three different cell lines that the downstream basic residues are required for cell adhesion whereas the CSVTCG sequence is not. Using mutant Chinese hamster ovary cells selected for deficiencies in proteoglycan synthesis, we show that in wild type cells, heparan sulfate proteoglycans are the binding sites for this motif. This finding is supported by additional experiments with two other cell lines demonstrating that treatment with heparitinase but not chondroitinase abolishes cell adhesion to peptides representing this motif. Using Chinese hamster ovary cell mutants deficient in heparan sulfate proteoglycans but possessing chondroitin sulfate proteoglycans, we show that cell surface chondroitin sulfate proteoglycans can also mediate binding to this motif although higher concentrations of peptides are required for adhesion. Chondroitinase, but not heparitinase, treatment of these cells destroys cell surface-binding sites. Taken together, these results indicate that cell adhesion to this motif involves an interaction between the downstream positively-charged residues and the negatively charged glycosaminoglycan chains of heparan sulfate, or in some cases chondroitin sulfate, proteoglycans on the cell surface.

[OKT3 treatment of refractory renal allograft rejection]

Between January 1993 and June 1996, 44 episodes of refractory renal allograft rejection were treated with OKT3 to understand the curative effect of OKT3. Six of 7 accelerated and 31 of 37 acute rejection episodes were reversed. The reverse rate was 84.6%. Immediate response to OKT3 was in 25 and delayed response in 12 patients. The mean reverse time was 7 +/- 4 days in immediate response and 34 +/- 3 days in delayed response (P < 0.01). It was claimed that OKT3 had high effect in the treatment of refractory renal allograft rejection. Cytomegalovirus infection and cytokins release syndrome were the main side effect of treatment with OKT3. The delayed response would be associated with cytokins release syndrome and damage of rejection. Patients with lower titre of anti-OKT3 antibodies could be retreated with OKT3.

Thalidomide suppresses T- and B-cell responses to myelin antigen in experimental allergic neuritis

The effects of thalidomide and, for reference, dexamethasone on T- and B-cell functions were assayed in vitro in Lewis rats with experimental allergic neuritis induced by active immunization with bovine peripheral nerve myelin (BPM) and complete Freund's adjuvant. Thalidomide and dexamethasone at the concentration ranges 10(-5)-10(-7) g/ml and 4 x 10(-5)-4 x 10(-9) g/ml, respectively, both inhibited phytohemagglutinin (PHA)- and BPM-induced T-cell proliferation as well as levels of PHA- and BPM-reactive interferon (IFN)-gamma-secreting cells, reflecting the suppression of Th1-like cells. The effect of dexamethasone was most pronounced on PHA-induced T-cell proliferation and IFN-gamma secretion, whereas the effect of thalidomide was most pronounced on BPM-induced T-cell proliferation and IFN-gamma secretion. Thalidomide reduced the B-cell responses to both BPM and Mycobacterium tuberculosis purified protein derivative, but to a lesser extent than dexamethasone. The in vitro design described could be useful to evaluate compounds with putative immunomodulatory activities. The inhibitory effects of thalidomide on autoantigen-induced Th1-cell functions may warrant the use of this substance in T-cell-mediated autoimmune diseases.

Structure of recombinant human CPP32 in complex with the tetrapeptide acetyl-Asp-Val-Ala-Asp fluoromethyl ketone

The cysteine protease CPP32 has been expressed in a soluble form in Escherichia coli and purified to >95% purity. The three-dimensional structure of human CPP32 in complex with the irreversible tetrapeptide inhibitor acetyl-Asp-Val-Ala-Asp fluoromethyl ketone was determined by x-ray crystallography at a resolution of 2.3 A. The asymmetric unit contains a (p17/p12)2 tetramer, in agreement with the tetrameric structure of the protein in solution as determined by dynamic light scattering and size exclusion chromatography. The overall topology of CPP32 is very similar to that of interleukin-1beta-converting enzyme (ICE); however, differences exist at the N terminus of the p17 subunit, where the first helix found in ICE is missing in CPP32. A deletion/insertion pattern is responsible for the striking differences observed in the loops around the active site. In addition, the P1 carbonyl of the ketone inhibitor is pointing into the oxyanion hole and forms a hydrogen bond with the peptidic nitrogen of Gly-122, resulting in a different state compared with the tetrahedral intermediate observed in the structure of ICE and CPP32 in complex with an aldehyde inhibitor. The topology of the interface formed by the two p17/p12 heterodimers of CPP32 is different from that of ICE. This results in different orientations of CPP32 heterodimers compared with ICE heterodimers, which could affect substrate recognition. This structural information will be invaluable for the design of small synthetic inhibitors of CPP32 as well as for the design of CPP32 mutants.

Activation of the CED3/ICE-related protease CPP32 in cerebellar granule neurons undergoing apoptosis but not necrosis

Neuronal apoptosis occurs during nervous system development and after pathological insults to the adult nervous system. Inhibition of CED3/ICE-related proteases has been shown to inhibit neuronal apoptosis in vitro and in vivo, indicating a role for these cysteine proteases in neuronal apoptosis. We have studied the activation of the CED3/ICE-related protease CPP32 in two in vitro models of mouse cerebellar granule neuronal cell death: K+/serum deprivation-induced apoptosis and glutamate-induced necrosis. Pretreatment of granule neurons with a selective, irreversible inhibitor of CED3/ICE family proteases, ZVAD-fluoromethylketone, specifically inhibited granule neuron apoptosis but not necrosis, indicating a selective role for CED3/ICE proteases in granule neuron apoptosis. Extracts prepared from apoptotic, but not necrotic, granule neurons contained a protease activity that cleaved the CPP32 substrate Ac-DEVD-aminomethylcoumarin. Induction of the protease activity was prevented by inhibitors of RNA or protein synthesis or by the CED3/ICE protease inhibitor. Affinity labeling of the protease activity with an irreversible CED3/ICE protease inhibitor, ZVK(biotin)D-fluoromethylketone, identified two putative protease subunits, p20 and p18, that were present in apoptotic but not necrotic granule neuron extracts. Western blotting with antibodies to the C terminus of the large subunit of mouse CPP32 (anti-CPP32) identified p20 and p18 as processed subunits of the CPP32 proenzyme. Anti-CPP32 specifically inhibited the DEVD-amc cleaving activity, verifying the presence of active CPP32 protease in the apoptotic granule neuron extracts. Western blotting demonstrated that the CPP32 proenzyme was expressed in granule neurons before induction of apoptosis. These results demonstrate that the CED3/ICE homolog CPP32 is processed and activated during cerebellar granule neuron apoptosis. CPP32 activation requires macromolecular synthesis and CED3/ICE protease activity. The lack of CPP32 activation during granule neuron necrosis suggests that proteolytic processing and activation of CED3/ICE proteases are specific biochemical markers of apoptosis.

[Dynamic study on blood lead levels of pregnant women and infants in a district of Beijing]

Under strict quality control, the authors investigated the levels of PbB among 270 women from early pregnancy to delivery and their infants. The mean PbB levels of the first three months of pregnancy and delivery is 45.0 microg/L and 64.8 microg/L respectively. Analysis shows an increase of mean PbB level in the period of gestation, and a significant increase in the last three months. The mean PbB level of umbilical cord is 51.9 microg/L (10.4% umbilical cord PbB > 100 microg/L). The mean PbB level of infants increases with the months, it increases significantly after six months. Regression analysis confirmed the positive correlation between the PbB levels of first three and second three months of gestation, the PbB of delivery and umbilical cord, the PbB of umbilical coral and infants. The correlation coefficient of the PbB level of delivery and umbilical cord, the PbB level of infants at six months and at twelve months is 0.80 and 0.47 respectively.

The relationship of fluorosis and brick tea drinking in Chinese Tibetans

Brick tea-drinking fluorosis is an unusual environmental problem. As a result of an investigation of tea-drinking habits, total fluoride intakes, dental fluorosis, and skeletal fluorosis, this disease has been found in the Sichuan Province of China in Tibetans with a long history of drinking brick tea. The dental fluorosis investigation of 375 Tibetan children (213 males, 162 females) and 161 Han children (86 males, 75 females), 8-15 years of age, was carried out in Daofu County, Sichuan Province. According to the standard of the Chinese Health Ministry, a skeletal fluorosis survey of 658 Tibetans (264 males, 394 females) and 41 Hans (20 males, 11 females), all over 16 years old, was performed. The total fluoride intake and fluorosis were determined from a question--calculation method in all participants. The morbidities of dental fluorosis in Tibetan and Han children are 51.2% and 11.05%, respectively, and the indexes of dental fluorosis are 1.33 and 0.17 (chi 2 = 75.7, p < 0.01) respectively. The morbidity of skeletal fluorosis is 32.83% for Tibetan children and zero for the Han children. The fluoride intakes of Tibetan children and adults were 5.49 mg/person/day and 10.43 mg/person/day, respectively, in this area. Of total everyday fluoride intake, 94.2% by children and 94.4% by adults was from brick tea and zanba (r = 0.99).

An animal cell mutant defective in heparan sulfate hexuronic acid 2-O-sulfation

The interaction of heparan sulfate with protein ligands depends on unique oligosaccharide sequences containing iduronic acid (IdUA), N-sulfated glucosamine residues, and O-sulfated sugars. To study the role of O-sulfation in greater detail, we isolated a Chinese hamster ovary cell mutant defective in 2-O-sulfation of iduronic acid. The mutant, pgsF-17, was identified by a colony blotting assay in which colonies of mutagen-treated cells were replica plated to two disks of polyester cloth. One disk was blotted with 125I-labeled basic fibroblast growth factor (bFGF) to measure binding to cell surface proteoglycans. The other disk was incubated with 35SO4 to measure proteoglycan biosynthesis. Autoradiography revealed a colony that did not bind 125I-bFGF, but incorporated 35SO4 normally (mutant pgsF-17). Complete deaminative cleavage of heparan sulfate revealed that material from pgsF-17 lacked IdUA(2OSO3)-GlcNSO3 and IdUA(2OSO3)-GlcNSO3(6OSO3), but contained a higher proportion of glucuronic acid GlcUA-GlcNSO3(6OSO3) and IdUA-GlcNSO3(6OSO3). Assay of the 2-O-sulfotransferase that acts on IdUA residues showed that mutant 17 lacked enzyme activity. Interestingly, the alteration resulted in accumulation of GlcNSO3 groups, suggesting that under normal conditions 2-O-sulfation decreases GlcNAc N-deacetylation/N-sulfation, and that the reactions occur simultaneously. The formation of IdUA and 6-O-sulfated glucosaminyl residues appears to be independent of 2-O-sulfation. pgsF-17 also lacks 2-O-sulfated GlcUA residues, suggesting that the same enzyme is responsible for 2-O-sulfation of IdUA and GlcUA residues. Mutant 17 provides a useful tool for studying the regulation of heparan sulfate biosynthesis and the relationship of heparan sulfate fine structure to its biological function.

Fas-induced activation of the cell death-related protease CPP32 Is inhibited by Bcl-2 and by ICE family protease inhibitors

The human proto-oncogene bcl-2 and its Caenorhabditis elegans homologue ced-9 inhibit programmed cell death. In contrast, members of the human interleukin-1beta converting enzyme (ICE) family of cysteine proteases and their C. elegans homologue CED-3 promote the death program. Genetic experiments in C. elegans have shown that ced-9 is formally a negative regulator of ced-3 function, but neither those studies nor others have determined whether CED-9 or Bcl-2 proteins act biochemically upstream or downstream of CED-3/ICE proteases. CPP32, like all known members of the CED-3/ICE family, is synthesized as a proenzyme that is subsequently processed into an active protease with specificity for cleavage at Asp-X peptide bonds. In this report, we demonstrate that the CPP32 proenzyme is proteolytically processed and activated in Jurkat cells induced to die by Fas ligation. CPP32 activation is blocked by cell-permeable inhibitors of aspartate-directed, cysteine proteases, suggesting that pro-CPP32 is cleaved by active CPP32 or by other ICE family members. Heterologous expression of Bcl-2 in Jurkat cells prevents Fas-induced cell death as well as proteolytic processing and activation of CPP32. Thus, Bcl-2 acts at or upstream of the CPP32 activation step to inhibit apoptosis induced by Fas stimulation.

[The changes in mucus components of intestine after burn and their relationship with bacterial translocation]

A dynamic observation at 0.5 hr, 1 hr, 6 hr, 12 hr and 24 hr after 25% third degree burn in 363 rats: 1) The lesions of mucous membrane of ileum. 2) Assessment of the depth of mucus layer and the contents of protein, hexose and sialic acid. 3) Estimation of the content of mucus IgA, serum IgA and the number of plasma cell producing IgA in mucous membrane. 4) Bacterial culture of mesentery lymph node. The following results were achieved: 1) Serious lesions were discovered in ileal mucous membrane. 2) Mucus IgA content was reduced markedly and the reduction was related to bacterial translocation.

[Effects of total saponins of semen ziziphi Spinosae on brain damages and brain biochemical parameters under cerebral ischemia of rats]

Total saponins of Semen Ziziphi Spinosae (ZS) can reduce the contents of water and MDA in ischemic rat's brain tissues, elevate the activity of SOD, CK and LDH, cut down the content of lactate and alleviate the damages of nerve cells in brain. The study shows that ZS possesses protective effects on cerebral ischemic injuries.

Acidic metabolites of tamoxifen. Aspects of formation and fate in the female rat

The nonsteroidal antiestrogen tamoxifen (TAM) is subject to extensive biotransformation in humans and laboratory animals. In particular, the dimethylamino group of TAM undergoes N-demethylation and formal replacement with a hydroxyl group, affording major metabolites TAM amine and TAM alcohol, respectively. In the present study in ovariectomized rats, TAM was eliminated in part as metabolites arising from conversion of its basic side chain to an oxyacetic acid moiety. Thus, TAM acid (TA) was characterized spectrally from the urine of rats after intraperitoneal administration of TAM. TA was not detected in fecal extracts. In contrast, a second metabolite, 4-hydroxy TA (4HTA), was detected and characterized only from fecal extracts, indicative of a qualitative difference in routes of elimination for TA and 4HTA. Studies with rat liver fractions suggested TAM alcohol to be an intermediate metabolite in the conversion of TAM to TA and 4HTA. In liver microsomal fraction, TAM alcohol was converted to a novel metabolite, TAM aldehyde, which was isolated and characterized as its semicarbazone derivative. Coenzyme requirements for formation of this (derivative) metabolite, as well as for conversion of TA to 4HTA, indicated these transformations to be catalyzed by cytochromes P450. TAM aldehyde was shown to be a plausible intermediate in the formation of acidic metabolites by experiments that indicated oxidation of this to TA was catalyzed by aldehyde oxidase derived from liver cytosolic fraction.

Synthesis and sigma binding properties of 2'-substituted 5,9 alpha-dimethyl-6,7-benzomorphans

The synthesis and sigma 1 and sigma 2 binding properties of several (+)- and (-)-2-benzyl- and 2-dimethylallyl-2'-substituted-5,9 alpha-dimethyl-6,7-benzomorphans (3 and 4) are presented. In agreement with previously reported binding data for 2-substituted 5,9 alpha-dimethyl-2'-hydroxy-6,7-benzomorphans (N-substituted-N-normetazocine), all (1S,5S,9S)-(+)-isomers showed higher affinity for the sigma 1 site than the corresponding (1R,5R,9R)-(-)-isomers. Replacement of the 2'-hydroxy group of (+)-2-benzyl-5,9 alpha-dimethyl-2'-hydroxy-6,7-benzomorphan [(+)-1f] with a 2'-NH2 and 2'-N(CH3)2 [(+)-3b and (+)-3c, respectively] had only a small effect on the sigma 1 Ki values. Changing the 2'-hydroxy group of (+)-1f to an H, F, Cl, Br, I, NHAc, or NHSO2CH3 resulted in a 5-fold or greater loss in potency. In contrast, replacement of the 2'-hydroxy group of (+)-2-(dimethylallyl)-5,9 alpha-dimethyl-2'-hydroxy-6,7-benzomorphan [(+)-1b, (+)-pentazocine] with a 2'-H or 2'-F group resulted in a 2-fold increase in potency. Conversion of (+)-1f to its 2'-desoxy analogue (+)-2d resulted in a 27.5-fold loss in affinity. This suggests that (+)-1f and other N-substituted benzomorphan analogues may be binding to single sigma 1 receptors in a different way or to different sigma 1 receptors. (-)-Pentazocine [(-)-1b] and its 2'-fluoro analogue, (-)-2-(dimethylallyl)-5,9 alpha-dimethyl-2'-fluoro-6,7-benzomorphan [(-)-4a] showed the highest potency for the sigma 2 binding site.