Estimation of individual phases from the four-phase structure invariants in the single isomorphous replacement case

The probability distribution of the four-phase invariants in the case of single isomorphous replacement has been developed to estimate some individual phases. An example of its application to obtain the phases having special values of 0, pi or +/-pi/2 is given for a known protein structure in space group P2(1)2(1)2(1). The phasing procedure includes the determination of starting phases and an iterative calculation. The initial values of starting phases, which are required by the formula, can be obtained from the estimate of one-phase seminvariants and by specifying the origin and enantiomorph. In addition, the calculations lead to two sets of possible phases for each type of reflection by assigning arbitrarily an initial phase value. The present method provides a possibility for the multisolution technique to increase greatly the number of known phases while keeping the number of the trials quite small.

[Effects of noise and music on EEG power spectrum]

Objective. To observe the effect of noise and music on EEG power spectrum. Method. 12 healthy male pilots aged 30 +/- 0.58 years served as the subjects. Dynamic EEG from 16 regions was recorded during quiet, under noise or when listening to music using Oxford MR95 Holter recorder. Changes of EEG power spectrum of delta, theta, alpha1, alpha2, beta1 and beta2, frequency components in 16 regions were analyzed. Result. The total alpha1 power was significantly decreased, while the total theta power was significantly increased when listening to music; It implies that the interhemispheric transmission of information in the frontotemporal areas might be involved. Conclusion. The changes of the EEG power spectrum were closely related to man's emotions; relaxation was associated with music; Individual difference exists in the influence of sound on EEG.

Development of salt-responsive neurons in the nucleus of the solitary tract

The rodent gustatory system has become a popular and useful model for the study of brain development because of this system's protracted period of postnatal maturation and its sensitivity to subtle changes in the animal's sensory environment. The goal of this investigation was to improve our understanding of dendritic remodeling exhibited by second-order gustatory neurons by presenting a comprehensive and definitive description of the development of the dendritic architecture of taste-sensitive neurons in the rostral nucleus of the solitary tract. Extracellular and intracellular recording and intracellular labeling techniques were used to examine the structure and function of individual gustatory neurons in three groups of rats: (1) Postnatal day 13-21 (PND13-21), (2) Postnatal day 22-28 (PND22-28), and (3) Adult (postnatal day 60-90). We found that neurons that responded to all three of the salts in our taste array ("Salt Sensitive") exhibited a striking increase in the number of dendritic branch points, maximum branch order, swelling density, and spine density between the PND13-21 and PND22-28 periods. These increases were followed by a period of dendritic remodeling during which the values for all measures except spine density decreased significantly. The neurons that did not respond to all three salts exhibited no change in the number of dendritic branches, branch order, or spine density during development, but they did undergo a decrease in swelling density. We also found that there was a significant decrease in the total dendritic length and cell volume of Salt Sensitive neurons between the PND22-28 and Adult periods, whereas the cells that did not respond to all three salts exhibited an increase in dendritic length and cell volume between postnatal day 28 and adulthood. Finally, we found that the dendrites of the Adult Salt Sensitive neurons were more restricted in the rostrocaudal axis than either the PND13-21 or PND22-28 Salt Sensitive cells. In contrast, there were no significant changes in the rostrocaudal extent of the dendritic arbors of cells that did not respond to all three salts. When viewed in the context of the extant literature and our own preliminary studies that used modified salt diets, we propose that these results provide strong support for the hypothesis that there is a relationship between postnatal dendritic development (particularly remodeling) and the animal's sensitivity to salts.

Upregulation of tyrosine kinase TKT by the Epstein-Barr virus transactivator Zta

The Zta protein is a key transactivator involved in initiating the Epstein-Barr virus (EBV) lytic cascade. In addition to transactivating many viral genes, Zta has the capacity to influence host cellular signals by binding to promoter regions or by interacting with several important cellular factors. Based on the observation that tyrosine kinases play central roles in determining the fate of cells, a kinase display assay was used to investigate whether cells expressing Zta have an altered pattern of kinase expression. The assay revealed that TRK-related tyrosine kinase (TKT) is expressed at significant levels in Zta transfectants but not in control cells. Additional evidence was obtained from Northern and Western blotting. Importantly, the upregulation of phosphorylated TKT and TKT downstream effector matrix metalloproteinase 1 in Zta transfectants hinted that TKT might initiate a signaling cascade in Zta-expressing cells. In addition, deletion analysis of the Zta protein revealed that the transactivation and dimerization domains were both essential for the upregulation of TKT transcription. Moreover, correlation of expression levels of Zta and TKT transcripts in nasopharyngeal carcinoma biopsy specimens was clearly demonstrated by quantitative PCR (Q-PCR), which provides the first evidence for an effect of Zta on cellular gene expression in vivo. These findings offer insight into the virus-cell interactions and may help us elucidate the role of EBV in tumorigenesis.

[The efficacy of parenteral nutrition with different energy for systemic inflammatory response syndrome (SIRS) in the aged]

To evaluate the efficacy and safety of parenteral nutrition (PN) with lower or higher energy for treating systemic inflammatory response syndrome (SIRS) in the aged, thirty old SIRS critically ill patients were involved in a randomized control clinical trial. Fifteen cases were treated by PN with lower energy (105 KJ.kg-1.d-1), and another fifteen cases with higher energy (146 KJ.kg-1.d-1) for 6 days. The data about metabolisms of protein, glucose and fat, blood gas analysis, acute physiology and chronic health evaluation (APACHE II) were analysed. The results showed that: 1. The effects of 105 KJ.kg-1.d-1 PN in increasing organism protein and maintaining nitrogen balance were the same as those of 146 KJ.kg-1.d-1 PN. 2. The levels of fast blood sugar and triglyceride maintained unchanged in 105 KJ.kg-1.d-1 PN group, while they increased significantly in 146 KJ.kg-1.d-1 PN group(P < 0.05). 3. PaO2 was raised greatly in 105 KJ.kg-1.d-1 PN group, while not in 146 KJ.kg-1.d-1 PN group. 4. 105 KJ.kg-1.d-1 PN and 146 KJ.kg-1.d-1 PN decreased APACHE II(P < 0.05), but the efficiency of 105 KJ.kg-1.d-1 PN was better than that of 146 KJ.kg-1.d-1 PN (P < 0.05). We conclude that PN with 105 KJ.kg-1.d-1 energy intake is more effective and safer for treating SIRS than that with 146 KJ.kg-1.d-1 in the aged.

Conformational correlation and coupled motion between residue A21 and B25 side chain observed in crystal structures of insulin mutants at position A21

The C-terminal residue of the insulin A chain is invariant and kept as asparagine in all known insulin molecules from hagfish through birds to mammals. To get information on the role of this conserved residue, which is still unclear, the three-dimensional structures of four human insulin mutants, A21 Asn-->Gly, A21 Asn-->Asp, A21 Asn-->Ala, and A21 Asn-->Gln DesB30, were determined by X-ray crystallography. The four mutants crystallize separately into two kinds (rhombohedral and cubic) of crystals. In the refined structures, conformational correlation and coupled motion between the A chain C-terminal residue A21 and the B25 side chain was observed, in contrast to the nearly unchanged general structures as compared with the native insulin structures in their respective crystals. A detailed analysis suggests that residue A21 can affect insulin receptor binding by interaction with the B25 side chain and the B chain C-terminal segment to assist the B25 side chain rearranging into the 'active' conformation.

Comparative genetics of nucleotide binding site-leucine rich repeat resistance gene homologues in the genomes of two dicotyledons: tomato and arabidopsis

The presence of a single resistance (R) gene allele can determine plant disease resistance. The protein products of such genes may act as receptors that specifically interact with pathogen-derived factors. Most functionally defined R-genes are of the nucleotide binding site-leucine rich repeat (NBS-LRR) supergene family and are present as large multigene families. The specificity of R-gene interactions together with the robustness of plant-pathogen interactions raises the question of their gene number and diversity in the genome. Genomic sequences from tomato showing significant homology to genes conferring race-specific resistance to pathogens were identified by systematically "scanning" the genome using a variety of primer pairs based on ubiquitous NBS motifs. Over 70 sequences were isolated and 10% are putative pseudogenes. Mapping of the amplified sequences on the tomato genetic map revealed their organization as mixed clusters of R-gene homologues that showed in many cases linkage to genetically characterized tomato resistance loci. Interspecific examination within Lycopersicon showed the existence of a null allele. Consideration of the tomato and potato comparative genetic maps unveiled conserved syntenic positions of R-gene homologues. Phylogenetic clustering of R-gene homologues within tomato and other Solanaceae family members was observed but not with R-gene homologues from Arabidopsis thaliana. Our data indicate remarkably rapid evolution of R-gene homologues during diversification of plant families.

[Prognostic effect of angina before acute myocardial infarction in elderly patients]

OBJECTIVE

The present study examined whether angina 48 h before acute myocardial infarction provided protection in early and adult patients. To investigate the effect of ischemic preconditioning in senescent heart.

METHODS

We retrospectively verified whether antecedent angina within 48 h myocardial infarction exerted a beneficial effect on in-hospital outcomes in adult(< 60 years old, n = 68) and elderly (> or = 60 years old, n = 118) patients.

RESULTS

In-hospital congestive heart failure was more frequent in adult patients without than in those with previous angina(16.7% vs 2.6%, P < 0.05), as were cardiogenic shock and death(23.3% vs 5. 3%, P < 0.05) and the combined end points(in-hospital congestive heart failure and shock or death) (40.0% vs 7.9%, P < 0.01). In contrast, the presence or absence of previous angina before acute myocardial infarction in elderly patients seemed to have no obvious influence, the incidence of in-hospital congestive heart failure(17.7% vs 20.0%, P > 0.05), shock and death(23.5% vs 20.3%, P > 0.05) and combined end points(41.2% vs 40.0%, P > 0.05). But the elderly patients with angina showed a significantly smaller infarct size compared with elderly patients without angina, the long-term cardiogenic death was more frequent in elderly patients without than in those with previous angina(18.0% vs 5.9%, P < 0.05).

CONCLUSIONS

The presence of angina before acute myocardial infarction seems to confer significant protection against in-hospital outcomes in adults; this effect seems to be present in elderly patients. This study suggests that the protection afforded by angina in adult and elderly patients may involve the occurrence of ischemic preconditioning.

Comparison of pure nicotine- and smokeless tobacco extract-induced toxicities and oxidative stress

The toxicities and oxidative stress-inducing actions of (-)-nicotine and smokeless tobacco extract (STE), containing equivalent amounts of nicotine, were studied. Toxicities were determined by colony formation assays using Chinese hamster ovary (CHO) cells. Results indicated that nicotine is less toxic than smokeless tobacco extract that contained the same amount of nicotine. The generation of reactive oxygen species, following treatment with smokeless tobacco extract and nicotine, was assessed by measurement of changes in glutathione (GSH) and malondialdehyde (MDA) levels. CHO cells (5 x 10(5) cells/5 ml media) were incubated with 4, 0.8, and 0.08 mg of nicotine and STE containing the same amounts of nicotine. All preparations of smokeless tobacco extract significantly decreased GSH levels and increased MDA generation. However, 0.08 mg of nicotine treatment did not result in a significant change in GSH level, and only 4 mg of nicotine were sufficient to increase MDA generation. Addition of free radical scavenging enzymes, superoxide dismutase (SOD) and catalase (CAT), and an intracellular GSH precursor, N-acetyl-L-cysteine (NAC), replenished the GSH levels in nicotine-treated cells. GSH levels in cells exposed to smokeless tobacco extract containing 4 and 0.8 mg nicotine remained significantly lower than the control with the addition of SOD and CAT. However, co-addition of NAC with smokeless tobacco extract preparations returned the GSH levels to the control level. Lactate dehydrogenase (LDH) activities were measured in the media to establish the membrane damage following exposure to smokeless tobacco extract and nicotine. Treatment of cells with 4 mg nicotine caused a significant increase in LDH activity, which was returned to control level in the presence of the antioxidant enzymes and NAC. Smokeless tobacco extract did not change the LDH activity. http://link.springer-ny. com/link/service/journals/00244/bibs/37n4p434.html</++ +HEA

Examination of ionic liquids and their interaction with molecules, when used as stationary phases in gas chromatography

Stable room-temperature ionic liquids (RTILs) have been used as novel reaction solvents. They can solubilize complex polar molecules such as cyclodextrins and glycopeptides. Their wetting ability and viscosity allow them to be coated onto fused silica capillaries. Thus, 1-butyl-3-methylimidazolium hexafluorophosphate and the analogous chloride salt can be used as stationary phases for gas chromatography (GC). Using inverse GC, one can examine the nature of these ionic liquids via their interactions with a variety of compounds. The Rohrschneider-McReynolds constants were determined for both ionic liquids and a popular commercial polysiloxane stationary phase. Ionic liquid stationary phases seem to have a dual nature. They appear to act as a low-polarity stationary phase to nonpolar compounds. However, molecules with strong proton donor groups, in particular, are tenaciously retained. The nature of the anion can have a significant effect on both the solubilizing ability and the selectivity of ionic liquid stationary phases. It appears that the unusual properties of ionic liquids could make them beneficial in many areas of separation science.

Use of infrared emission detection thermometer in Chinese neonates

OBJECTIVE

To evaluate the reproducibility of Thermoscan, an infrared emission detection ear thermometer, and to establish the normal reference range of ear temperature in Chinese neonates.

METHODS

Neonates were recruited from the inpatients population with exclusion of those suffering from infections.

RESULTS

Forty-nine neonates were recruited with 1,115 temperature taking sessions. Mean left ear temperature was 36.64 degrees C +/- 0.35 degree C. Mean right ear temperature was 36.64 degrees C +/- 0.37 degree C. Clinical repeatability for left and right ear was 0.17 degree C and 0.17 degree C, respectively.

CONCLUSION

Thermoscan produced reproducible results in Chinese neonates. The normal range of ear temperature for Chinese neonates is 35 degrees C to 37 degrees C. Ear temperature > 37.8 degrees C should be regarded as fever.

Bilateral idiopathic infantile pyoceles: a case report

A 15-day-old infant was admitted to the 803 Military Hospital with swelling, bilateral erythematous changes, a tender firm mass in the scrotum and fever of six hours' duration. Scrotal sonography showed accumulated fluid with internal echoes in both hydrocele sacs. Aspirated fluid was found to contain Escherichia coli and bilateral scrotal pyoceles was diagnosed. The most common etiologic factor for this is meconium peritonitis, with surgical drainage being the necessary treatment. The case is reported, with a review of the literature.

Design, implementation, and characterization of an optical power supply spot-array generator for a four-stage free-space optical backplane

The design and implementation of a robust, scalable, and modular optical power supply spot-array generator for a modulator-based free-space optical backplane demonstrator is presented. Four arrays of 8 x 4 spots with 6.47-mum radii (at 1/e(2) points) pitched at 125 mum in the vertical direction and 250 mum in the horizontal were required to provide the light for the optical interconnect. Tight system tolerances demanded careful optical design, robust optomechanics, and effective alignment techniques. Issues such as spot-array generation, polarization, power efficiency, and power uniformity are discussed. Characterization results are presented.

Transcriptional analysis of the threonine dehydrogenase gene of Xanthomonas campestris

The nucleotide sequence has previously been determined for the Xanthomonas campestris pv. campestris gene coding for threonine dehydrogenase (tdh). Flanking this gene are the upstream region possessing promoter activity and the downstream perfect inverted repeat having potential to form a stem-loop structure which resembles a transcription terminator. In addition, Northern blot analysis suggested the transcript of this gene to be monocistronic. In the present study, the essential region for promoter activity was narrowed down to a stretch of 57 bp which still retained 84% of the promoter activity. The first nucleotide to be transcribed is the guanosine at 30 nt upstream from the proposed tdh start codon. The putative terminator exhibited transcriptional termination activity bidirectionally in both Escherichia coli and X. campestris. These observations indicate that the transcriptional structure of X. campestris tdh is different from that of E. coli where tdh and kbl are organized into the tdh operon. Furthermore, the expression of tdh in X. campestris is repressed by leucine, a situation different from that in E. coli where leucine induces the expression of tdh operon.

Optomechanics for a four-stage hybrid-self-electro-optic-device-based free-space optical backplane

We present the design, fabrication, and testing of optomechanics for a free-space optical backplane mounted in a standard 6U VME backplane chassis. The optomechanics implement an optical interconnect consisting of lenslet-to-lenslet, as well as conventional lens-to-lens, links. Mechanical, optical, electrical, thermal, material, and fabrication constraints are studied. Design trade-offs that affect system scalability and ease of assembly are put forward and analyzed. Novel mounting techniques such as a thermal-loaded interference-fitted lens-mounting technique are presented and discussed. Diagnostic tools are developed to quantify the performance of the optomechanics, and experimental results are given and analyzed.

Molecular characterization of the gene coding for threonine dehydrogenase in Xanthomonas campestris

The Xanthomonas campestris pv. campestris 17 gene tdh, which codes for the threonine dehydrogenase (TDH), was cloned and sequenced. The deduced gene product, a polypeptide consisting of 340 amino acids (Mr = 37,048), has 63.5% identity to the E. coli TDH in amino acid sequence and shares residue conservation with the alcohol/polyol dehydrogenases from different organisms. TDH activity was not detectable in the tdh mutant constructed by gene replacement; however, the enzyme activity in the mutant complemented in trans by a plasmid containing the complete tdh sequence was increased by 15 folds over Xc17. Northern blot analysis detected an mRNA with a size similar to that of the Xc17 tdh coding region, suggesting that the tdh gene-containing transcript may be monocistronic.

Combinations of three immunological assays for detecting anti-Toxoplasma IgG in the sera of patients infected with Toxoplasma gondii

Enzyme-linked immunosorbent assay (ELISA), Dot-ELISA and Dot-immunogold silver staining (Dot-IGSS) were simultaneously used to detect the specific IgG against Toxoplasma gondii in 65 patients infected with the protozoa. The positive rates were 86.51%, 92.51% and 98.64%, respectively. When ELISA and Dot-ELISA results were put together, the positive rate increased to 95.38%. When Dot-IGSS results were combined with those of ELISA or Dot-ELISA, the positive rate was raised to 100%. The difference in positive rate between ELISA and Dot-IGSS was significant (x2 = 6.93, p < 0.01), but no statistically significant differences were found between ELISA and Dot-ELISA or between Dot-ELISA and Dot-IGSS. Paired comparison of the reacting intensities of the sera in the 3 assays showed the correlations were highly significant (p < 0.001), with r = 0.608 between Dot-IGSS and Dot-ELISA, r = 0.8194 between Dot-IGSS and ELISA and r = 0.517 between Dot-ELISA and ELISA. Hence combination of different serological assays may increase their sensitivity and specificity for detecting the anti-Toxoplasma antibodies.

Frequency and clinico-pathological associations of ras mutations in colorectal cancer in the Victorian population

BACKGROUND

Mutations in the oncogene ras occur in 20-50% of colorectal cancers. The presence of these mutations allows screening tests to be developed based on the identification of mutant DNA in cells derived from cancers. A study of the prevalence and clinicopathological associations of ras mutations was undertaken.

METHODS

The frequency of mutations in codons 12 and 13 of the K-ras gene was investigated in 103 colorectal carcinomas using restriction fragment length polymorphism.

RESULTS

Mutations were detected in 32% (33/103) of the tumours, predominantly in codon 12 (25/33). No mutations were detected in normal-appearing mucosa from the same patients.

CONCLUSIONS

Analysis of the frequency of ras mutations compared with various independent clinical variables revealed a sex-linked relationship between the presence of a ras mutation and nodal status but no correlation with any other clinical parameter was found. The findings suggest that screening tests based on ras mutation detection may lack sensitivity because of the presence of mutations in only 32% of tumours.

Phosphotyrosine phosphatase activity in the macrophage is enhanced by lipopolysaccharide, tumor necrosis factor alpha, and granulocyte/macrophage-colony stimulating factor: correlation with priming of the respiratory burst

Tyrosine phosphorylation is now recognised as a key event in the activation of the macrophage respiratory burst. Since vanadate, a phosphotyrosine phosphatase (PTP) inhibitor is able to enhance the respiratory burst, we proposed that agents which prime the macrophage for enhance respiratory burst activity may do so by suppressing cellular PTP activity. The level of PTP activity in murine bone marrow-derived macrophages (BMM) was assessed by the ability of cell lysates to dephosphorylate 32P-labelled RR-src peptide. In contrast to our hypothesis, pretreatment of BMM with bacterial lipopolysaccharide (LPS), tumor necrosis factor alpha (TNF alpha) or granulocyte/macrophage-colony stimulating factor (GMCSF), agents which prime for enhanced respiratory burst activity, was found to dramatically increase the level of cellular PTP activity. The time-course for this increase correlated well with the time course of priming by these agents. In addition, colony stimulating factor-1, a cytokine which does not prime the macrophage respiratory burst, did not enhance PTP levels. The physiological relevance of the increased PTP activity was further supported by confirming it was active against endogenous tyrosine phosphorylated substrates. Interestingly, phorbol myristate acetate and zymosan, agents which trigger the macrophage respiratory burst, were found to inhibit the PTP activity of BMM. Our results demonstrate the regulation of cellular PTP activity by priming agents and further highlight the importance of tyrosine phosphorylation and dephosphorylation events in the regulation of macrophage function.

Heparin and heparan sulfate bind to snake cardiotoxin. Sulfated oligosaccharides as a potential target for cardiotoxin action

Cardiotoxins (CTXs) from cobra venom show cytotoxicity toward several cell types. They cause systolic heart arrest and severe tissue necrosis. Their interaction with phospholipids is established but by itself fails to explain the specificity of these toxins; other component(s) of membrane must, therefore, intervene to direct them toward their target. We herein show, for the first time, that sulfated glycosaminoglycans, heparin, heparan sulfate (HS), chondroitin sulfate (CS), and dermatan sulfate (DS), interact with CTX A3, a major component of Taiwan cobra venom, by use of affinity chromatography, circular dichroism, absorbance, and fluorescence intensity and anisotropy measurements. The relative strength of binding, determined by the NaCl concentration required to dissociate the CTX-glycosaminoglycan complex, varied as follows: heparin > DS > CS > HS. In physiological buffer (8 mM Na2HPO4, 2.7 mM KCl, 1.8 mM KH2PO4, 138 mM NaCl, pH 7.4), however, only heparin and HS bound to CTX, with respective dissociation constants of 1.4 and 16 microM, while CS and DS failed to exhibit well defined binding behavior, as indicated by fluorescence measurements. We estimate that CTX makes 3-4 ionic contacts with heparin based on a salt-dependent binding study and that approximately 40% of binding free energy is derived from purely electrostatic interactions under physiological conditions. Sulfated pentasaccharide may be sufficient to bind to CTX. We also found that heparin accentuates the penetration of CTX into phospholipid membranes as analyzed by Langmuir monolayer measurement. In view of these results we propose that heparin-like moieties of the cell surface may modulate the action of CTX.

4 x 4 vertical-cavity surface-emitting laser (VCSEL) and metal-semiconductor-metal (MSM) optical backplane demonstrator system

We describe a system demonstrator based on vertical-cavity surface-emitting lasers, metal-semiconductor-metal detectors, printed circuit board (PCB) level optoelectronic device packaging, a compact bulk optical relay, and novel barrel/PCB optomechanics. The entire system was constructed in a standard VME electrical backplane chassis and was capable of operating at >1.7 Gbit/s of aggregate data capacity. In addition to the component technologies developed, we describe operational testing and characterization of the demonstrator.

Dot-immunogold-silver staining in the diagnosis of cysticercosis

Dot-immunogold-silver staining (Dot-IGSS) and Dot-ELISA were used, with Taenia solium cyst fluid antigen, to detect specific antibodies in the sera of patients with cysticercosis. All 40 confirmed cases of cysticercosis were found to be positive when tested by 2 methods. The average titer of the sera detected by Dot-IGSS was 1:27,470, which was significantly higher than that detected by Dot-ELISA. The false positive rates were 2% and 4% in 50 healthy controls for Dot-IGSS and Dot-ELISA, respectively, with a low titer of 1:20.

Application of dot-immunogold-silver staining in the diagnosis of clonorchiasis

All 35 confirmed clonorchiasis cases showed a positive reaction in dot-immunogold-silver staining (Dot-IGSS) with a mean serum titre of 1:1656, while none of the sera from 35 normal individuals reacted. A seroepidemiological survey of middle-school students revealed a positive rate of 17.0% (142/836), and 76.1% (105/138) of the serologically positive students were egg positive in stool examination. The egg positive rates in those with antibody at levels of 1+ to 4+ were 57.1% (28/49), 75.7% (28/37), 94.7% (36/38) and 92.9% (13/14) respectively. It is believed that Dot-IGSS can be used for the clinical diagnosis and epidemiological survey of clonorchiasis.

Single-step direct PCR amplification from solid tissues

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