An NMR and mutational study of the pseudoknot within the gene 32 mRNA of bacteriophage T2: insights into a family of structurally related RNA pseudoknots

NMR methods were used to investigate a series of mutants of the pseudoknot within the gene 32 messenger RNA of bacteriophage T2, for the purpose of investigating the range of sequences, stem and loop lengths that can form a similar pseudoknot structure. This information is of particular relevance since the T2 pseudoknot has been considered a representative of a large family of RNA pseudoknots related by a common structural motif, previously referred to as 'common pseudoknot motif 1' or CPK1. In the work presented here, a mutated sequence with the potential to form a pseudoknot with a 6 bp stem2 was shown to adopt a pseudoknot structure similar to that of the wild-type sequence. This result is significant in that it demonstrates that pseudoknots with 6 bp in stem2 and a single nucleotide in loop1 are indeed feasible. Mutated sequences with the potential to form pseudoknots with either 5 or 8 bp in stem2 yielded NMR spectra that could not confirm the formation of a pseudoknot structure. Replacing the adenosine nucleotide in loop1 of the wild-type pseudoknot with any one of G, C or U did not significantly alter the pseudoknot structure. Taken together, the results of this study provide support for the existence of a family of similarly structured pseudoknots with two coaxially stacked stems, either 6 or 7 bp in stem2, and a single nucleotide in loop1. This family includes many of the pseudoknots predicted to occur downstream of the frameshift or readthrough sites in a significant number of viral RNAs.

Changes of plasma tPA and PAI activities in patients with diabetic retinopathy

PURPOSE

To investigate the relationship between the diabetic retinopathy (DR) and the activity of plasma tissue plasminogen activator (tPA) and plasminogen activator inhibitor (PAI).

METHODS

tPA and PAI activities were measured by chromatogenous substrate assay in plasma samples obtained from patients with and without diabetic retinopathy (n = 42). Retinopathy was determined by stereoscopic color fundus photographs graded according to a modification of Chinese National Fundus Disease Academic Meeting. And 21 sex-age matched normal people were as controls. This study was in a masked fashion.

RESULTS

1. tPA activity was lower and PAI activity was higher in all of diabetic patients than those in controls (P < 0.001); 2. tPA activity was lower and PAI activity was higher in proliferative DR (PDR) subgroup than those in non-DR (NDR) and background-DR (BDR) subgroups (P < 0.01, respectively); 3. there was no significant difference between BDR and NDR subgroups (P > 0.05); and 4. the results also suggested that the severity of DR and duration of diabetes were correlated negatively with the activity of tPA but positively with that of PAI (r = -0.564, -0.416, 0.671, 0.442; P < 0.01, respectively).

CONCLUSIONS

Reduced plasma tPA activity and enhanced PAI activity in diabetic patients, probably is one of the causes for thromboembolic diseases and are related to the severity of DR and duration of diabetes. Therefore, the change and imbalance between activities of plasma tPA and PAI might play a role in developing and progression of DR.

[Expression of FGF-b and C-myc in rats lung tissue affected by hypoxia]

OBJECTIVE

To study FGF's roles in the reconstruction of vascular walls owing to chronic hypoxia.

METHOD

40 SD rats [corrected] were divided into different hypoxia groups and proceeded with various hypoxic intervals. Expression of FGF-b and transcription of c-myc mRNA of the rats [corrected] lung tissues were detected by immunohistochemical method and in situ hybridization.

RESULTS

FGF-b increased obviously in the smooth muscle and advential tissue of pulmonary arteries after 14 days of hypoxia, whereas C-myc mRNA showed overexpression in rats [corrected] lung tissue from 7th to 21st day of hypoxia.

CONCLUSION

(1) Hypoxia may lead to activation of C-myc oncogene and increase of FGF-b expression in lung tissue. (2) FGF-b and C-myc oncogene takes part in reconstruction of pulmonary arterial wall affected by chronic hypoxia.

In vivo phosphorylation of phosphoenolpyruvate carboxylase in guard cells of Vicia faba L. is enhanced by fusicoccin and suppressed by abscisic acid

Plants regulate water loss and CO2 gain by modulating the aperture sizes of stomata that penetrate the epidermis. Aperture size itself is increased by osmolyte accumulation and consequent turgor increase in the pair of guard cells that flank each stoma. Guard cell phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31), which catalyzes the regulated step leading to malate synthesis, is crucial for charge and pH maintenance during osmolyte accumulation. Regulation of this cytosolic enzyme by effectors is well documented, but additional regulation by posttranslational modification is predicted by the alteration of PEPC kinetics during stomatal opening (FEBS Lett. 352, 45-48). In this study, we have investigated whether this alteration is associated with the phosphorylation status of this enzyme. Using sonicated epidermal peels ("isolated" guard cells) preloaded with 32PO4, we induced stomatal opening and guard cell malate accumulation by incubation with 5 microM fusicoccin (FC). In corroboratory experiments, guard cells were incubated with the FC antagonist, 10 microM abscisic acid (ABA). The phosphorylation status of PEPC was assessed by immunoprecipitation, electrophoresis, immunoblotting, and autoradiography. PEPC was phosphorylated when stomata were stimulated to open, and phosphorylation was lessened by incubation with ABA. Thus, we conclude that regulation of guard cell PEPC in vivo is multifaceted; the effects of regulatory metabolites and the activation status of the enzyme are integrated to control malate synthesis. These results, together with the coincident alteration in the kinetics of the enzyme (FEBS Lett. 352, 45-48), constitute the first unequivocal demonstration of regulatory posttranslational modification of a guard cell protein that is specifically implicated in stomatal movements.

[Stability of jingu tongxial pills]

The stability of Jingu Tongxiao Pills was studied on the basis of accelerated destruction and sample-reserving observation at room temperature. According to the changes of tanshinone IIA in the sample, the time of efficacy determined by the two methods is 1.89 and 2.30 years respectively. Based on the analysis of other indices, the effective period is tentatively determined as two years.

Copper metabolism of holstein and jersey cows and heifers fed diets high in cupric sulfate or copper proteinate

Eight Holstein and 8 Jersey primiparous cows (3 d postcalving) and 8 Holstein and 8 Jersey growing heifers were randomly assigned to 1 of 8 treatments in a 2 x 2 x 2 factorial arrangement to compare Cu metabolism between Holsteins and Jerseys and the bioavailabilities of Cu in Cu proteinate and CuSO4. The variables were Holstein or Jersey, Cu supplementation at 5 or 80 mg/kg of DM, and supplements of CuSO4 or Cu proteinate. Jerseys had higher hepatic Cu concentrations than did Holsteins on d 60 (346 vs. 303 micrograms/g of DM). At the high Cu supplementation, hepatic Cu increased more rapidly, and content was higher in Jerseys than in Holsteins by d 60 (520 vs. 439 micrograms/g of DM). On d 0, plasma Cu concentrations were 0.99 and 0.80 microgram/ml, and, on d 60, concentrations were 0.96 and 0.88 microgram/ml for Jerseys and Holsteins, respectively. Overall, serum ceruloplasmin oxidase activity was greater for Jerseys than for Holsteins. Jersey cows and heifers also had greater hepatic Fe (208 vs. 173 micrograms/g of DM) and lower hepatic Zn (82 vs. 91 micrograms/g of DM) than did Holstein cows and heifers at d 60. The bioavailability of Cu in Cu proteinate and CuSO4 was the same. Plasma Cu concentration and ceruloplasmin have limited value as indicators of Cu status and availability to dairy cows and heifers.

A hammerhead ribozyme that cleaves perforin and fas-ligand RNAs in vitro

Polyfunctional ribozymes targeting more than one RNA might be ideal for treatment of diseases caused by the expression of more than one mRNA. This is the case of Graft versus Host Disease, which in the mouse model is due to the action of two proteins responsible for different lytic pathways: perforin and fasligand. We have created a bifunctional ribozyme fusing two antiperforin and antifas-ligand hammerhead ribozymes with a stretch of CA dinucleotides. This bifunctional ribozyme is able to recognize and cleave in vitro perforin and fas-ligand mRNA in a specific and selective fashion, with a catalytic efficiency similar to that of its individual components.

Utilization of copper in copper proteinate, copper lysine, and cupric sulfate using the rat as an experimental model

One hundred twenty male Sprague-Dawley rats, averaging 108.6 g initial body weight, were used in two feeding experiments to evaluate the utilization of Cu in Cu proteinate, Cu lysine, and cupric sulfate. In Exp. 1, 60 rats were randomly assigned to 12 treatments in a 2 x 2 x 3 factorial arrangement of treatments, with Zn supplementation at 0 or 1000 mg/kg diet, Cu supplementation at 5 or 15 mg/kg diet, and Cu form of CuSO4.5H2O, Cu proteinate, or Cu lysine. The purified basal diet contained .81 mg Cu, 20 mg Zn, and 60 mg Fe/kg diet. Experiment 2 was similar to Exp. 1 except Zn was replaced by Fe. In Exp. 1, feed intake of Cu proteinate (15.74 g/d) and Cu lysine (15.74 g/d) treatments was higher (P < .05) than that of CuSO4 (15.33 g/d). Body weight gain and feed intake were increased by high dietary Cu at either requirement or high levels of dietary Zn (P < .05). There were no differences in feed intake or body weight gain among the treatment groups in Exp. 2 (P > .05). The Cu utilization of Cu proteinate and Cu lysine were higher (P < .05) based on the liver Cu content. The rats fed Cu complexes had a higher liver Fe or Zn content (P < .05) than the rats fed CuSO4, suggesting that Cu complexes are absorbed via another mechanism that differs from that of inorganic Cu and does not interfere with Zn and Fe. Spleen Cu content may be a sensitive indicator of Cu status. High dietary Zn decreased Cu utilization, but this effect was overcome by high dietary Cu.

Induction of lymphocyte proliferation and severe gastrointestinal disease in macaques by a nef gene variant SIVmac239

The molecularly cloned virus known as SIVmac239/YEnef causes extensive lymphocyte activation in unstimulated peripheral mononuclear cell cultures and induces an acute disease syndrome in macaque monkeys. Here we describe the histopathological and immunophenotypic changes and viral localization in peripheral lymph nodes, spleen, and gastrointestinal tract (including the gut-associated lymphoid tissue (GALT) in rhesus monkeys inoculated with SIVmac239/YEnet beginning at day 3 postinoculation (pi). The findings are compared with those of rhesus monkeys inoculated with the same dose of parental SIVmac239. Histopathological examination of peripheral lymphoid tissue and GALT demonstrated marked hyperplasia of T-cell-dependent regions and involution of germinal centers as early as day 7 pi. The most striking lesions were multifocal areas of lymphohistiocytic gastroenteritis and colitis. Cellular infiltrates peaked between day 7 and 14 pi and were composed primarily of CD3+ T lymphocytes and HAM-56+ monocyte/macrophages. Many of these inflammatory cells were also strongly immunoreactive for teh nuclear proliferation antigen Ki-67. Despite the presence of severe gastrointestinal pathology by day 7 pi, no significant difference in the numbers of virus-positive cells in the gastrointestinal tract was observed between these animals and SIVmac239-infected animals examined at the same time point. However, the distribution of virus in the gastrointestinal tract was markedly different, with virus localized to lymphoid nodules of GALT in SIVmac239-infected animals and restricted to areas of lymphohistiocytic gastroenteritis and colitis in animals infected with SIVmac239/YEnef. Our data indicate that the acute disease syndrome induced by SIVmac239/YEnef is not simply related to increased viral replication in the gastrointestinal tract but is likely due to inappropriate virus-induced T lymphocyte activation and proliferation in GALT and subsequent mucosal destruction.

Requirements for lymphocyte activation by unusual strains of simian immunodeficiency virus

When residues 17 and 18 in nef of simian immunodeficiency virus strain SIVmac239 were changed from RQ to YE, the resultant virus was able to replicate in peripheral blood mononuclear cell cultures without prior lymphocyte activation and without the addition of exogenous interleukin-2, caused extensive lymphocyte activation in these cultures, and produced an acute disease in rhesus and pigtail macaques (Z. Du, S. M. Lang, V. G. Sasseville, A. A. Lackner, P. 0. Ilyinskii, M. D. Daniel, J. U. Jung, and R. C. Desrosiers, Cell 82:665-674, 1995). These properties are similar to those of the acutely lethal pathogen SIVpbj14 but dissimilar to those of the parental SIVmac239. We show here that the single change of R to Y at position 17 in nef of SIVmac239 is sufficient to confer the full, unusual phenotype. Conversely, the lymphocyte-activating properties of SIVpbj14 were lost by the single change of Y to R at position 17 of nef. The change of R17F or Q18E in SIVmac239 nef did not confer the unusual in vitro properties. Since SIVpbj14 has a duplication of the NF-kappaB binding sequence in the transcriptional control region, we also constructed and tested strains of SIVmac239/Rl7Y with zero, one, and two NF-kappaB binding elements. We found no difference in the properties of SIVmac239/R17Y, either in cell culture or in vivo, whether zero, one, or two NF-kappaB binding sites were present. Thus, tyrosine at position 17 of nef is absolutely necessary for the unusual phenotype of SIVpbj14 and is sufficient to convert SIVmac239 to a virus with a phenotype like that of SIVpbjl4. Multiple NF-kappaB binding sites are not required for the in vitro properties or for acute disease.

Effect of isothermal radiofrequency radiation on cytolytic T lymphocytes

Previous in vitro studies provide evidence that RF electromagnetic radiation modulates proliferation of human glioma, lymphocytes, and other cell types. The mechanism of RF radiation cell proliferation modulation, as well as mechanisms for effects on other cell physiologic endpoints, are not well understood. To obtain insight regarding interaction mechanisms, we investigated effects of RF radiation exposure on interleukin 2 (IL-2) -dependent proliferation of cytolytic T lymphocytes (CTLL-2). After exposure to RF radiation in the presence or absence of IL-2 cells were cultured at various physiological concentrations of IL-2. Treatment effects on CTLL-2 proliferation were determined by tritiated thymidine incorporation immediately or 24 h after exposure. Exposure to 2450 MHz RIF radiation at specific absorption rates (SARs) of greater than 25 W/kg (induced E-field strength 98.4 V/m) induced a consistent, statistically significant reduction in CTLL-2 proliferation, especially at low IL-2 concentrations. At lower SARs, 2450 MHz exposure increased CTLL-2 proliferation immediately after exposure but reduced 24 h postexposure proliferation. RF radiation effects depended on the mitotic state of the cells at the time of exposure. Comparison of the effects of temperature elevation and RF radiation indicated significant qualitative and quantitative differences.

FTIR studies of recombinant human granulocyte-macrophage colony-stimulating factor in aqueous solutions: secondary structure, disulfide reduction and thermal behavior

Fourier transform infrared spectroscopy (FTIR) has been used to investigate the secondary structure, disulfide reduction and thermal behavior of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) in aqueous solutions. The contributions of amino-acid side-chain groups to the amide I bands of rhGM-CSF in H2O and in D2O solutions were carefully scrutinized, as 40% of the total 127 amino-acid residues of rhGM-CSF is side-chain absorptive (asparagine, glutamine, etc.). The FTIR results indicated that rhGM-CSF is composed of 46% alpha-helix, 7% beta-sheet, 23% turn and 24% loop/irregular structures which are in good agreement with the X-ray diffractional data. Reduction of rhGM-CSF with dithiothreitol caused apparent unfolding of the native conformation followed by the time-dependent increase of beta-aggregation bands which arose at 1622 and 1693 cm(-1) in H2O, 1613 and 1684 cm(-1) in D2O solutions. The result also showed that tertiary structure can change independently of the secondary structure. Thermal denaturation of rhGM-CSF took place at 55 to 70 degrees C and the denatured protein adopted an irregular structure as revealed by the FTIR spectra. The thermal denaturation did not show the formation of intermolecular beta-aggregates which is typical of most thermal denatured proteins. Moreover, it is partly reversible, indicating a special thermal stability of rhGM-CSF.

Internalization of Kit together with stem cell factor on human fetal liver-derived mast cells: new protein and RNA synthesis are required for reappearance of Kit

Kit, the receptor for stem cell factor (SCF) and the product of the c-kit proto-oncogene, is expressed on fetal liver-derived mast cell progenitors when cultured with SCF. Decreased levels of Kit on the surface of human fetal liver-derived mast cells after exposure to recombinant human SCF were demonstrated by flow cytometry using the YB5.B8 mAb against Kit. Internalization of Kit along with SCF appears to be the principal means by which Kit is lost from the mast cell surface. Neither the beta 3-integrin CD51/CD61 (alpha v beta 3), nor the beta 1-integrins CD49d,e/CD29 (VLA-4 and -5) appeared to be internalized along with Kit-SCF complexes. Reappearance of Kit on day 28 fetal liver-derived mast cells is complete 3 days after exposure of the cells to SCF and is detectable by 2 days. Recovery requires new protein and new RNA synthesis, because Kit did not reappear if cycloheximide or actinomycin D was added to the cells. No substantial change in total Kit mRNA was detected during the resynthesis period, suggesting that post-transcriptional regulation of Kit production is involved. Internalization of Kit in mast cells exposed to soluble SCF may represent a negative regulatory mechanism for this receptor-ligand interaction and down-regulate mast cell properties such as degranulation to SCF.

Internalization of Kit together with stem cell factor on human fetal liver-derived mast cells: new protein and RNA synthesis are required for reappearance of Kit

Kit, the receptor for stem cell factor (SCF) and the product of the c-kit proto-oncogene, is expressed on fetal liver-derived mast cell progenitors when cultured with SCF. Decreased levels of Kit on the surface of human fetal liver-derived mast cells after exposure to recombinant human SCF were demonstrated by flow cytometry using the YB5.B8 mAb against Kit. Internalization of Kit along with SCF appears to be the principal means by which Kit is lost from the mast cell surface. Neither the beta 3-integrin CD51/CD61 (alpha v beta 3), nor the beta 1-integrins CD49d,e/CD29 (VLA-4 and -5) appeared to be internalized along with Kit-SCF complexes. Reappearance of Kit on day 28 fetal liver-derived mast cells is complete 3 days after exposure of the cells to SCF and is detectable by 2 days. Recovery requires new protein and new RNA synthesis, because Kit did not reappear if cycloheximide or actinomycin D was added to the cells. No substantial change in total Kit mRNA was detected during the resynthesis period, suggesting that post-transcriptional regulation of Kit production is involved. Internalization of Kit in mast cells exposed to soluble SCF may represent a negative regulatory mechanism for this receptor-ligand interaction and down-regulate mast cell properties such as degranulation to SCF.

Thermodynamics of folding of the RNA pseudoknot of the T4 gene 32 autoregulatory messenger RNA

Nucleotides U(-67) to C(-40) at the extreme 5' end of the gene 32 mRNA in bacteriophage T4 have been shown to fold into an RNA pseudoknot proposed to be important for translational autoregulation. The thermal denaturation of three in vitro transcribed RNAs corresponding to the pseudoknot region has been investigated as a function of Mg2+ concentration to begin to elucidate the determinants of the structure and stability of this conformation. T4-35 is a 35-nucleotide RNA containing a 5' G followed by the natural T4 sequence starting with the mature 5' end of the mRNA, nucleotides A(-71) to C(-38). A 32-nucleotide RNA, termed T4-32, contains the native sequence form U(-67) to C(40) with 5'GC and 5'CA single-stranded regions appended to the 5' and 3' ends of the core sequence, respectively. T4-28 contains only the 28 core nucleotides, and the predicted closing U(-67)-A(-52) base pair in stem 1 has been replaced with a phylogenetically allowed G(-67)-C(-52) base pair. Ribonuclease mapping of T4-32 and imino proton NMR experiments of T4-35 show that both sequences adopt a pseudoknotted conformation. At pH 6.9 and 50 mM NaCl, T4-35 and T4-32 RNAs are characterized by a single major melting transition over a wide range of [Mg2+] (0-6 mM). The delta H degree of unfolding for T4-35 and T4-32 shows a large dependence on Mg2+ concentration; the maximum delta H degree occurs at about 2.0 mM Mg2+ with further addition of Mg2+ simply increasing the tm. Investigation of the [Mg2+] dependence of the tm suggests that a net of one Mg2+ ion is released upon denaturation of T4-35 and T4-32 RNAs. Over the entire [Mg2+] range, the delta G degree (37 degrees C) for the folding of T4-35 is consistently 1-1.5 kcal mol(-1) more negative than T4-32 due to a higher stabilization enthalpy for the natural sequence molecule. In contrast to this behavior, T4-28 gives consistently higher tm's but less negative enthalpies and is destabilized (at 37 degrees C) by about 0.5-1.5 kcal mol(-1) relative to T4-32 and by about 2-3 kcal mol(-1) relative to T4-35, depending upon cation concentration. (1)H NMR experiments suggest that, even in the presence of 4.0 mM Mg2+, T4-28 RNA does not adopt a stable pseudoknotted conformation. These data show that the stability of the pseudoknot in the gene 32 mRNA encoded by the 28-nucleotide core sequence is significantly influenced by the number and nature of the immediately adjacent "single-stranded" 5' and/or 3' nucleotides appended to the core structure. These findings are discussed within the context of the structural model for the evolutionarily related phage T2 and T6 gene 32 mRNA pseudoknots presented in the following paper [Du, Z., Giedroc, D. P., & Hoffman, D. W. (1996) Biochemistry 35, 4187-4198].

Structure of the autoregulatory pseudoknot within the gene 32 messenger RNA of bacteriophages T2 and T6: a model for a possible family of structurally related RNA pseudoknots

A 36-nucleotide RNA with a sequence corresponding to the 5' end region of the gene 32 mRNA of bacteriophages T2 and T6 was analyzed by one- and two-dimensional NMR methods. NMR results provide clear evidence that the RNA is folded into a pseudoknot structure with two coaxial stems connected by two loops, in a classic pseudoknot topology. The pseudoknot is unusual in that one of the loops consists of only one nucleotide, which spans the major groove of a seven base pair helical stem. Imino proton resonances indicate the hydrogen bonding pattern within the pseudoknot, and two-dimensional NOE spectra provide information that describes many of the structural features. The temperature dependence of the UV absorption and imino proton exchange rates provides insight into the stability of the pseudoknot. A three-dimensional model of the pseudoknot that is consistent with our NMR data is presented, and features that may be important for stabilizing the pseudoknot structure are discussed. A substantial number of other putative RNA pseudoknots described in the literature have sequences and topologies that appear to be related to the T2 and T6 pseudoknots. We propose that these RNAs may be members of a family of pseudoknots related by a similar structural motif, which we refer to as "common pseudoknot motif 1" or CPK1. The bacteriophage T2/T6 pseudoknot can be considered a structural model for the CPK1 family. The common features of the CPK1 pseudoknots are a stem 2 with six or seven base pairs, a loop 1 consisting of a single adenosine, and a variable length stem 1 and loop 2. The first "dangling" nucleotide at the 3' end of the molecule probably stabilizes stem 2. The CPK1 family includes several of the retroviral pseudoknots associated with mRNA frameshifting and readthrough. The work presented here describes the first detailed NMR analysis of an RNA pseudoknot with an entirely natural nucleotide sequence.

Structure of 1,3,5,7-tetranitro-3,7-diazabicyclo-[3.3.0]octane. Structure solution from molecular packing analysis

The structure was solved with the molecular packing program MOLPAK, starting with a molecular mechanics-geometry optimized model of an isolated molecule. The best predicted crystal structures from the MOLPAK procedure were subjected to lattice energy refinement with the WMIN program. The MOLPAK/WMIN-predicted crystal structure, whose cell parameters were closest to the experimental values, gave an initial R of 0.48 for the 173 data to 0 = 25°. Four cycles of least-squares refinement of x, y, z and U gave an R of 0.27 for the 277 data to 0 = 30°. Final R = 0.038, wR = 0.044. There are no unusual intermolecular distances and crystal packing is normal.

Target imaging diagnosis of human brain glioma. Clinical analysis of 40 cases

OBJECTIVE

To establish a method for localization and qualitative diagnosis of glioma.

METHODS

The monoclonal antibody SZ-39 against human glioma was labelled with 131I and injected intravenously into 40 patients with intracranial occupying lesions proved by X-CT. 72 hours after 131I-McAb-SZ39 administration, cranial bone nuclide-imaging agent 99mTc-MDP was injected intravenously, and the patients were examined by SPECT scan with dual nuclide double channel tomography and special software. On radio-immuno-image, the immunocomplex formed by specific conjugation of 131I-McAb-SZ39 with target tissue was red, while the cranial bone incorporated with 99mTc-MDP was green. The location of the immunocomplex area could be identified by the superimposition of the images.

RESULTS

21 patients with positive targeting diagnosis of glioma showed the accuracy rate checked by SPECT was 81%(17/21) and by X-CT 48% (10/21). Seven patients with negative targeting diagnosis showed the accuracy rate checked by SPECT was 86%(6/7) and by X-CT 14% (1/7). Pathologically, the sensitivity of targeting SPECT to glioma was 94.5%(17/18) and that of X-CT 55%(10/18).

CONCLUSIONS

Targeting SPECT examination could be used for localization and qualitative diagnosis of glioma and make up the inadequacy of X-CT in the qualitative diagnosis of atypical incipient and recurrent glioma, meningioma, metastatic carcinoma, and inflammatory lesions of brain.

[Investigation and experimental study on the standards and quality of leech pieces]

It has been confirmed by investigation that Whitmania pigra is the main medicinal breed of leech, and filiform pieces are the best for extraction. The quality of leech processed by 3 different methods has been studied qualitatively and quantitatively in terms of amounts of extraction, TLC, electrophoresis of protein and anti-thrombin action.

Identification of a nef allele that causes lymphocyte activation and acute disease in macaque monkeys

Residues 17 and 18 in nef of SIVmac239 were changed from RQ to YE to create a translated sequence of SRPSGDLYERLLRARGETYGRLLGEVEDGYSQSP from residues 10-43. The YXXL motifs in this context match very well with consensus sequences for SH2 binding domains and are similar to ones present in nef of the acutely lethal pathogen SIVpbj14. The YE variant of SIVmac239, unlike SIVmac239 but like SIVpbj14, replicated well in resting peripheral blood mononuclear cell cultures, caused extensive T lymphocyte activation, and produced an acute disease in rhesus and pigtailed monkeys characterized by severe diarrhea, rash, and extensive lymphoid proliferation in the gastrointestinal tract. The YEnef gene transformed NIH 3T3 cells in culture. Both 239nef and YEnef were found to associate with src in cotransfected COS cells, and both 60 kDa src and 34 kDa nef were phosphorylated at tyrosine in these cells. The extent of tyrosine phosphorylation of 239nef was considerably less than that of YEnef in these assays. These findings identify an important determinant of the SIVpbj14 phenotype, and they provide evidence of a role for nef in signal transduction and cellular activation.

Influence of penning type and feeding level on sexual behavior and feet and leg soundness in boars

Ninety-six Yorkshire males at 28 d of age were placed on a pre-test feeding regimen (22% CP) of either ad libitum (A) access to feed or a restricted (R, 85% of A) diet. All pigs were housed in groups of four until approximately 30 kg body weight. The boars were then placed under test and assigned to a group pen (GP) containing eight boards or to individual pens (IP) and fed a 16% CP diet at A or R levels. Feeding types during pre-test and test phases were, therefore, ad libitum followed by ad libitum (AA), ad libitum: restricted (AR), restricted: ad libitum (RA), and restricted: restricted (RR) for each of the two (IP and GP) housing types. All boars were weighed every 2 wk to determine the feeding level and ADG. The pen floors were partly slatted with water nipples in the slatted areas. Areas available for each board were 1.63 and 2.15 m2 in IP and GP, respectively. Sexual behavior, semen characteristics, and feet and leg scores were recorded between 150 and 240 d of age. The IP boards required longer (P < .05) contact with receptive gilts before mating, made more (P < .01) ano-genital sniffings, and attempted more (P < .10) incorrect mounts than GP boars. The GP boards had a higher (P < .01) mating score, younger (P < .001) age at completion of the mating test, and lower (P < .01) total sperm count and sperm concentration (P < .001) than IP boars. The AA boards exhibited less (P < .10) chomping and salivation than boars on other feeding regimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Complete nucleotide sequence of Saccharomyces cerevisiae chromosome VIII

The complete nucleotide sequence of Saccharomyces cerevisiae chromosome VIII reveals that it contains 269 predicted or known genes (300 base pairs or larger). Fifty-nine of these genes (22 percent) were previously identified. Of the 210 novel genes, 65 are predicted to encode proteins that are similar to other proteins of known or predicted function. Sixteen genes appear to be relatively recently duplicated. On average, there is one gene approximately every 2 kilobases. Although the coding density and base composition across the chromosome are not uniform, no regular pattern of variation is apparent.

Structure of 1,1,5,5-tetranitro-[4]peristylane. Structure solution from molecular packing analysis

The structure of the title compound, decahydro-2,2,5,5-tetranitro-1,6:3,4-dimethanocyclobuta[1,2: 3, 4]dicyclopentene, C12H12N4O8, was solved with the molecular packing program MOLPAK, starting with an AM1-geometry-optimized model of an isolated molecule. The 20 best predicted crystal structures from the MOLPAK procedure were subjected to lattice energy refinement with the WMIN program. A structure-factor calculation with the top MOLPAK/WMIN derived structure and the 197 Fo data to sin theta/lambda = 0.324 A-1 (theta = 30 degrees) gave an R value of 0.29. Final R = 0.057, wR = 0.067 for 730 reflections with I > 3 sigma (I). There are no unusual intermolecular distances and crystal packing is normal.

Kinetic characterization of phosphoenolpyruvate carboxylase extracted from whole-leaf and from guard-cell protoplasts of Vicia faba L. (C3 plant) with respect to tissue pre-illumination

Whole leaves and guard-cell protoplasts of the C3 plant Vicia faba L. (broad bean) were separately extracted following a period of illumination or following a period of darkness. Kinetic parameters of phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31), Vmax and Km(PEP.Mg), were determined as a function of assay pH (7.0 or 8.1), the presence of 5 mM glucose-6-Pfree (Glc-6-P, an activator), and the presence of 5 mM malatefree (an inhibitor). On the basis of these parameters, guard-cell PEPC was distinguished from that of whole leaf, indicating either that guard cells contain a unique isoenzyme of PEPC or a different complement of isoenzymes or--and less likely--that the obligatorily different methodologies for the leaf (intact organ) and the guard-cell (protoplast) enzymes altered them specifically. The values of Vmax were relatively unchanged, regardless of assay conditions or tissue pretreatment. The values obtained for whole-leaf PEPC Vmax were restricted to a small range (52.4 +/- 5.9 (SD) to 64.4 +/- 4.8 (SD) mumol.g fresh mass-1.h-1; the high value coincided with the presence of Glc-6-P, and the low value was obtained in the presence of malate. Guard-cell PEPC Vmax was also restricted to a small range: 7.48 +/- 0.89 (SD) pmol.guard-cell pair-1.h-1 (pH 8.1, light, +Glc-6-P) to 5.79 +/- 0.60 (SD) pmol.guard-cell pair-1.h-1 (pH 7.0, dark, +malate). Depending on effectors, and particularly pH, large changes in Km(PEP.Mg) were calculated (whole-leaf PEPC: 0.03 to 3.84 mM; guard-cell PEPC: 0.06 to 3.43 mM).(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical trials for removal of bilirubin by high-capacity nonionic adsorbent

To remove bilirubin from patients with hyperbilirubinemia, nonionic macroporous adsorbent NK-110 was tailor-made from styrene and divinyl benzene at Nankai University. Five patients were perfused through shunts filled with 500 ml of the above adsorbent. After 2 h of hemoperfusion, total bilirubin decreased within the range of 22-51%. During the treatment, no noticeable changes in electrolytes, urea nitrogen, serum glutamicpyruvic transaminase (SGPT), TTT, and amino acid concentrations were observed. Platelet depletion was satisfactory. Hemoglobin, white cell count, globulin, and albumin showed no remarkable changes. The nonionic adsorbent shows a high efficacy for bilirubin removal and has a great potential for future clinical applications.

Automated fluorescent DNA sequencing of polymerase chain reaction products

The methods described in this chapter provide some useful approaches for DNA sequencing of templates produced by PCR. These procedures have been employed successfully for large-scale DNA sequencing of cosmid fragments subcloned in plasmid or M13 vectors, and for sequence analysis of cDNAs cloned in bacteriophage lambda vectors. In addition, the method describing direct sequencing from PEG-precipitated PCR product has been used successfully for analysis of Caenorhabditis elegans genomic and cDNA sequences. It is important to reiterate that for every combination of amplification primer pair and target DNA, there is an optimal method for PCR amplification; the ability to sequence the products of any PCR experiment directly will also vary. A coupled PCR/DNA sequencing method that works well for one experimental system may work quite poorly with others. Hence, a few days or hours spent optimizing PCR amplification conditions and selecting the best DNA sequencing method for the target DNA of interest will be time well spent.

Fluorescence chemistries for automated primer-directed DNA sequencing

A major limitation in the applicability of automated DNA sequencing instruments has been the difficulty in using user-defined oligonucleotide primers which allow sequencing reactions to start at any specific point in a region of interest. Recently, new chemistries have become available for fluorescent labeling which will begin to facilitate the use of any oligonucleotide primer with automated DNA sequencers. In this report, we describe several methods for automated primer-directed DNA sequencing, and compare and discuss the relative merits and limitations of these methods.

[Comparative study on activity of adenylate cyclase in normal human ovary with ovarian tumors]

It has been documented that the binding activity sites of human chorionic gonadotropin (HCG) receptor and kd in human ovarian tumors are different from those in the normal ovary. And some observations suggest that the HCG receptor depends on adenylate cyclase (AC) for its physiological functions. We studied the activity of AC in normal human ovary and ovarian tumors. Five human ovarian specimens and eighteen ovarian tumor specimens were obtained from women patients undergoing gynecological surgery. Ovaries were homogenized and sonicated. The homogenates were centrifuged at 1000 x g for 15 min. After sucrose density gradient ultracentrifugation (78000 x g, 4 h), the membrane fraction was collected from interface between 33% and 37%. The membrane protein approximately 10 micrograms, ATP 1 mmol/L, 3H-ATP 5 x 10(4) cpm, sulphydryl-ethyl alcohol 10 mmol/L, in a final volume of 200 microliters of Tris-HCl buffer (50 mmol/L), pH7.5, containing MgSO4 5 mmol/L, were incubated at 35 degrees C for 10 min. The reaction was stopped by boiling water bath for 3 min. The AC activity (U/mg): of human normal ovary, 67 +/- 8, of cystadenocarcinoma serous, 146 +/- 70; of cystadenocarcinoma mucinous, 289 +/- 83.

The C. elegans genome sequencing project: a beginning

The long-term goal of this project is the elucidation of the complete sequence of the Caenorhabditis elegans genome. During the first year methods have been developed and a strategy implemented that is amenable to large-scale sequencing. The three cosmids sequenced in this initial phase are surprisingly rich in genes, many of which have mammalian homologues.

[Establishment of standard strains of serotypes (groups) of Streptococcus pneumoniae in China]

Streptococcus pneumoniae is an important human pathogen which is responsible for life-threatening infections such as pneumonia, bacteremia and meningitis as well as for less severe but highly prevalent diseases such as otitis media and sinusitis. The number of serogroups (types) of Streptococcus pneumoniae found in the world is total 46 groups or 83 types according to typing system of Statens Serum Institute, Copenhagen, Denmark. The standard strains established in our lab of 42 groups or 67 types distributed in 17 different regions in China. The significance of this study is that two of the new serotypes (10C, 16A) are first reported in the literature in which the microbes were the agents causing pneumococcal infections. Our standard strains also include some serotypes on rare occasions such as 19C and 22A and 33C which have been found only in Asia. Our findings not only increase the total number of known types of pneumococci from 83 to 85, but also indicate that China has made progress in the field of pneumococcal research. It is the first time to report establishing a series of standard strains of pneumococci involving many serotypes (groups) in China. The work is necessary as a preliminary for pneumococcal disease prevention and treatment. The standard strains listed here with providing the resource of strain and scientific basis for developing vaccine and biological products.