Complement fixing antibody production in thymectomized Oncorhynchus mykiss, vaccinated against or infected with the pathogenic haemoflagellate Cryptobia salmositica

Short-term thymectomized (two months after thymectomy) adult rainbow trout, Oncorhynchus mykiss (Walbaum) infected with the flagellate Cryptobia salmositica Katz, 1951 responded well during primary infection with C. salmositica and recovered fish also showed secondary response (rapid production of complement fixing antibody after homologous challenge) five months after recovery. Complement fixing antibody was detected during primary and secondary responses and the titres of complement fixing antibody in thymectomized fish were significantly lower than those in infected intact fish. The parasitaemia in thymectomized infected fish was significantly lower than in intact infected fish. Both recovered thymectomized fish and intact fish were protected from cryptobiosis when they were challenged. Similarly, long-term thymectomized fish (nine months after thymectomy) vaccinated with an attenuated strain of C. salmositica were protected from cryptobiosis. There were no significant difference (P > 0.05) in parasitaemia, packed cell volume and complement fixing antibody titres between vaccinated/challenged thymectomized and vaccinated/challenged intact fish. Hence, thymectomy in adult rainbow trout did not decrease the detectable complement fixing antibody against C. salmositica in long-term thymectomized fish but reduced the detectable protective antibody in short-term thymectomized fish.

A homeo-interaction sequence in the ectodomain of the fibroblast growth factor receptor

Interaction of fibroblast growth factor receptors (FGFR) sufficient for a trans-phosphorylation event in which one intracellular domain is substrate for the other is essential for signal transduction. By analysis of the direct interaction of recombinant constructions co-expressed in baculoviral-infected insect cells, we identified a 17-amino acid sequence that is required for the stable interaction between ectodomains of FGFR. The sequence 160ERSPHRPILQAGLPANK176 (Glu160-Lys176) connects immunoglobulin modules II and III. In insect cells, the interaction between Glu160-Lys176 domains occurs independently of intact heparin or FGF binding domains. The sequence is not required for the binding of heparin or FGF-1, but is essential for mitogenic activity of the FGFR kinase in mammalian cells. The results support a model in which the homeo-interaction between Glu160-Lys176 in the ectodomain contributes to the interaction between intracellular domains in mammalian cell membranes (Kan, M., Wang, F., Kan, M., To, B., Gabriel, J. L., and McKeehan, W. L. (1996) J. Biol. Chem. 271, 26143-26148). We propose that the Glu160-Lys176 domain plays a pivotal role in restriction of the interaction between kinases by pericellular matrix heparan sulfate proteoglycan and divalent cations. Restrictions are overcome by FGF or constitutively by diverse gain of function mutations which cause skeletal and craniofacial abnormalities.

A sensitive GC-MS procedure for the analysis of flunitrazepam and its metabolites in urine

Analysis of urine specimens collected from individuals ingesting 2 and 4 mg flunitrazepam (FN) showed positive results by OnLine and OnTrak immunoassays for up to 60 h. Gas chromatographic-mass spectrometric (GC-MS) analysis of these specimens for FN, 3-OH-FN, 7-amino-FN, 7-amino-3-OH-FN, desmethyl-FN, and 3-OH-desmethyl-FN after glucuronidase treatment showed only low levels of 7-amino-FN with almost none of the other metabolites. These levels were far below the expected results based on the immunoassay data. This study reports on a GC-MS procedure for FN and the previously listed metabolites. The method is based on acid hydrolysis of the urine specimens, which converts FN and all its metabolites described previously to one of four amino-benzophenone derivatives (1-4) with oxazepam-d5 as the internal standard. Under the experimental conditions, the internal standard is converted to 2-amino-5-chloro-benzophenone-d5. The limit of detection for 7-amino-FN and 7-amino-desmethyl-FN and their 3-OH derivatives was less than 1 ng/mL. Analysis of urine specimens collected for 72-h postingestion of 1, 2, or 4 mg FN showed appreciable levels of benzophenone 3 (product of 7-amino-FN and 7-amino-3-OH-FN) and lower levels of benzophenone 4 (product of 7-amino-desmethyl-FN and 7-amino-3-OH-desmethyl-FN) with no detectable levels of benzophenones 1 and 2. The method makes it possible to confirm the presence of FN metabolites in urine at least 72-h postingestion of small doses of the drug.

Flunitrazepam excretion patterns using the Abuscreen OnTrak and OnLine immunoassays: comparison with GC-MS

A study was conducted to compare the performance of the OnLine and OnTrak immunoassays for benzodiazepines with gas chromatographic-mass spectrometric (GC-MS) analysis in detecting flunitrazepam (FNP) and its metabolites in human urine. Urine was collected over a 72-h period from six individuals (four male and two female) who had taken a single oral dose of either 1 or 4 mg of FNP. The OnTrak assay was run at a 100-ng/mL cutoff of nordiazepam (NDP), and the OnLine assay was run with a standard curve from zero to 200 ng/mL of NDP with and without beta-glucuronidase treatment. Each sample was analyzed by GC-MS using FNP, 7-amino-FNP, 3-hydroxy-FNP, desmethyl-FNP, 7-amino-3-hydroxy-FNP, and desmethyl-3-hydroxy-FNP as standards with beta-glucuronidase treatment. The specimens from the 1-mg dose did not yield a positive result by immunoassay over the 72-h collection period. Specimens from the 4-mg dose did yield positive results in both immunoassays. The time of the first positive result ranged from 4 to 12 h, and the time to the last positive result ranged from 18 to 60 h. Treatment of the samples with beta-glucuronidase increased the OnLine values between 20 and 60%, but it did not appreciably increase the detection time. GC-MS analysis showed no detectable levels of FNP, 3-hydroxy-FNP, desmethyl-FNP, 7-amino-3-hydroxy-FNP, and desmethyl-3-hydroxy-FNP. However, all samples collected past time zero showed detectable levels of 7-amino-FNP (> 2 ng/mL) with peak concentrations at 12-36 h. The peak levels of 7-amino-FNP by GC-MS paralleled the peak levels of the immunoassay response. The amount of 7-amino-FNP metabolite quantitated by GC-MS, however, accounted for only 15-20% of the total immunoassay crossreactive FNP metabolites.

Relationship of necrosis to organ failure in severe acute pancreatitis

BACKGROUND & AIMS

Pancreatic necrosis and organ failure are principal determinants of severity in acute pancreatitis. The purpose of this study was to determine the relationship of necrosis to organ failure in severe acute pancreatitis.

METHODS

Patients with necrotizing pancreatitis from May 1992 to January 1996 were retrospectively studied. Pancreatic necrosis was identified by characteristic findings on dynamic contrast-enhanced computerized tomography scan and infected necrosis by computerized tomography-guided percutaneous aspiration. Organ dysfunction was defined in accordance with the Atlanta symposium.

RESULTS

Organ failure was present in only 26 of 51 patients (51%). There was no difference in the prevalence of organ failure in infected necrosis compared with sterile necrosis (approximately 50% in both groups). Patients with increased amounts of necrosis did not have an increased prevalence of organ failure or infected necrosis compared with those with lesser amounts of necrosis. Patients with organ failure had an increased morbidity and mortality compared with those without organ failure.

CONCLUSIONS

Organ failure occurred in only one half of patients with necrotizing pancreatitis. Because organ failure increases the severity of illness, studies of patients with necrotizing pancreatitis must stratify for organ failure to facilitate interpretation of results.

[The killing effect of IL-2 and IFN-alpha activated bone marrow on K562 leukemic cell]

OBJECTIVE

To evaluate the killing effect of IL-2 and IFN-alpha activated bone marrow cells on K562 cells.

METHODS

Semi-solid colony assay was used.

RESULTS

Bone marrow from leukemia patients in remission was activated in vitro with IL-2 for 3 days. The activated bone marrow (ABM) displayed killing effects of 0.31 approximately 2.30 logs on K562 cells, this killing effects was further increased to 0. 30 approximately > 3.15 logs when IFN-alpha added with IL-2 to the marrow for activation. IL-2 alone or in combination with IFN-alpha showed no inhibition of CFU-GM and K562 cells. Compared with IL-2 or IFN-alpha alone, the combination of the two cytokines could more effectively maintain the killing effect of ABM on leukemic cells.

CONCLUSION

IFN-alpha can augment the purging effect of IL-2 ABM and combination of the two cytokines can effectively maintain the cytotoxicity of ABM.

[Catalytic fluorimetric determination of trace amount of bromine ion]

A new catalytic fluorimetric method for the determination of bromine ion based on its catalytic effect on the oxidation of fluorescein by potassium bromate in the solution of dilute sulfuric acid has been established. The detection limit for Br- is 1.94 x 10(-2) microg/25 mL. The linear range of the determination is 6.0-12.0 microg/25 mL. The method has been applied to the determination of Br- in tablet pyridostigmini bromidum sample with satisfactory results.

[Scopes and applications of LeFort III advancement osteotomy]

In order to correct craniofacial retrusion and malocculusion caused by Crouzon syndrome, we employed LeFort III advancement osteotomies in 21 cases in last 10 years. The differences between craniofacial appearances and cephalometric analyses pre- and postoperatively showed that good results were achieved in all cases. No severe complications in these series were found.

Versatile retrovirus vector systems for regulated gene expression in vitro and in vivo

BACKGROUND

Several plasmid DNA-based mammalian expression systems have recently been developed which make it possible to manipulate gene expression via the administration of exogenous agents. In order to extend the application of these systems, we have developed retroviral vectors which allow for the controlled expression of inserted genes both in vitro and in vivo.

MATERIALS AND METHODS

Two vector strategies which make use of the tetracycline-regulated gene expression system described by Gossen and Bujard were evaluated. In a first strategy, one virus was generated which encoded the tTA or rtTA transactivator gene product, and a second virus was generated in which expression of the gene of interest was dependent upon tetracycline-responsive transcriptional control elements placed either within the viral LTR or within the proviral transcriptional unit. In a second vector strategy, both components of the tet-regulatable system were incorporated into a single proviral genome in such a way that expression of both the transgene and the transactivator gene product were under control of tet-regulatable control elements.

RESULTS

Both vector strategies resulted in the ability to regulate the expression of inserted genes. In one single virus configuration, gene expression could be regulated over 100X and the level of gene expression in the induced state was comparable to or greater than that achieved with standard LTR-based vectors. The use of different deletions in the viral LTR made it possible to generate a number of vectors which provide for a four-fold range of levels of expression of inserted genes in the induced state. Studies in mice with transduced cells demonstrated that gene expression could be induced in vivo by manipulation of tetracycline for at least 48 days.

CONCLUSIONS

The availability of highly transmissible, regulatable retroviral vectors should greatly facilitate studies in which it is of interest to manipulate the expression of specific genes in vitro or in vivo.

Protective and arthritis-resolving activity in sera of mice infected with Borrelia burgdorferi

Transfer of immune serum from immunocompetent mice infected with B. burgdorferi protects mice against syringe challenge, and transfer of immune serum after infection is established induces arthritis resolution but does not clear infection or spirochetemia or resolve carditis. Immune serum had very-high-titer passive protective activity against syringe challenge but failed to protect mice against host-adapted spirochetes when they were challenged with infected tissue transplants. Mice were passively immunized at selected intervals relative to challenge inoculation with antisera to recombinant forms of an immunodominant region of flagellin, P39, and OspC (which are recognized by immune serum), but none provided protection or modified existing infection or disease. Results suggest that spirochetes within joints, but not in other tissues, are selectively vulnerable to immune serum and that immune serum appears to contain antibody against yet-to-be-identified antigens that may be selectively expressed in the context of joint tissue.

[Observation of 212 cases of typhoid fever treated with FQNS]

OBJECTIVES

To treat 212 cases of typhoid fever with Seven kinds of fluoroquinolones (FQNS) and to evaluate their clinical efficacy, bacterial susceptibility and adverse drug reaction (ADR).

METHODS

All the cases were hospitalized and uniantibiotic treated in which NFX group (n = 43) was compared with CP group (n = 28).

RESULTS

204/212 (96.23%) cases were positively cultured. All except 9 (S. paratyphi) were S. typhi. Of the 212 clinically isolated strains, 194(91.51%) were susceptible to FQNS with K-B assay. The MIC except 1 (6.25 mg/L) were all < or = 4 mg/L. The results of MIC detection with 20 strains of clinically isolated bacteria in 1994 and 1995 showed that FQNS were apparently superior to other antityphoid fever antibiotics as chloramphenicol and cefoperazone. When FQNS were used the overall clinical cure rate was 98.11%, the bacterial clear rate was 99.51%, and the rate of ADR was 11.3%. No difference was found between the NFX group and CP group in defervescent days and the cure rates and bacterial carrier state in recovery. The rate of recurrence and ADR in the NFX group was lower than that in the CP group. With the improvement of pharmacokinetics, new FQNS can be administered once or twice a day, and the therapy course shortened from 14 to 7 days. It is considered that FQNS are currently the first choice of antibacterials in treating typhoid fever.

[Effect of bone marrow transplantation conditioning regimen on thyroid and adrenocortical functions in patients with blood diseases]

OBJECTIVE

In order to investigate the life quality of patients with hematological diseases after bone marrow transplantation (BMT).

METHODS

Pituitary-thyroid and adrenocortical function were de tected in 29 patients with hematological diseases before and after BMT.

RESULTS

All patients had normal thyroid and adrenocortical functions before BMT. As compared with pre-BMT,the median serum TSH levels were significantly increased at 3, 6, 12 (P<0.01), 24-60 (P<0.05) months post-BMT. The adrenocortical function had no change in all patients, and thyroid dysfunction were found in 6 of 24 patients detected at a median time of 6 month post-BMT. Five of the 6 thyroid dysfuntion patients developed hypothyroidism, and one hyperthyroidism.

CONCLUSION

There was little effect of conditioning regimen on adrenocortical function, while thyroid dysfunction was common after BMT. Long term follow up on thyroid function in patients after BMT is necessary.

[Determination of degradation level of antifungal agent in mice serum by high performance liquid chromatography]

L-4-oxalysinyl-norvalinyl-N3-4-methoxyfumaroyl-L-2,3-diaminopropanoic acid (I-677-Nva-FMDP) is a new tripeptide synthesized in our group. This peptide exhibits potent anticandida Albicans activity. In the presence of serum, the antifun gal activity of I-677-Nva-FMDP decreases after incubating over 1h. In order to investigate the relationship between the degradation and antifungal activity of I-677-Nva-FMDP, the concentrations of I-677-Nva-FMDP and N3-methoxyfumaroyl-L-2,3-diaminopropanoic acid (FMDP) were determined at different incubating time in mice serum. The incubating time range was from 0 to 300 min and the incubating samples were measured at intervals of 30 min. For this measurement reversed-phase HPLC was used and the mobile phase was composed of 8% methanol and 0.1% trifluoroacitic acid-triethyl amine buffer (pH 3). In this condition the retention time of FMDP and I-677-Nva-FMDP were 3.9 min and 16.5 min respectively. Methanol was superior to other reagents for the removal of protein from the incubating medium and there was not any interference peak before the retention time of I-677-Nva-FMDP. A decrease in concentration of I-677-Nva-FMDP was observed from 0 min to 180 min and no I-677-Nva-FMDP could be detected at 210 min whereas the concentration of FMDP incresed from 30 min to 2h and reached a maximum at 120 min. The results showed that the half life (t1/2) of I-677-Nva-FMDP was 70 min. This result coincided with the antifungal test in vitro.

[In vitro reversal of homoharringtonine resistance by the combination of tamoxifen and verapamil]

OBJECTIVE

To investigate the reversal of homoharringtonine (HHT)-resistance by tamoxifen (TAM) or verapamil (VER) alone or in combination.

METHODS

The drug-sensitivity test was performed with semisolid agar culture.

RESULTS

The cytotoxicity of HHT to K562/S cells was not enhanced by TAM or VER alone or in combination,but HHT resistance in HHT resistant cells (K562/H20) was reversed by VER and TAM at nontoxic doses (4micromol/L or 8micromol/L). The IC50 of K562/H20 for HHT decreased from 446.8 +/- 0.08microg/L to 45.1 +/- 0.02microg/L in the presence of 4micromol/L of VER, to 22.4 +/- 0.03microg/L in 8micromol/L of VER, to 85.1 +/- 0.03microg/L in 4micromol/L of TAM and to 26.4 +/- 0.02microg/L in 8micromol/L of TAM. In the presence of combinations of 2micromol/L VER and 4micromol/L TAM and of 2micromol/L VER and 8micromol/L TAM, IC50 of K562/H20 decreased to 30.4 +/- 0.02microg/L and 4.3 +/- 0.04microg/L, respectively.

CONCLUSION

HHT-resistance could be reversed by VER or TAM alone, and the combination of the two drugs showed a synergistic effect.

A processive versus a distributive mechanism of action correlates with differences in ability of normal and xeroderma pigmentosum group A endonucleases to incise damaged nucleosomal DNA

A DNA endonuclease, isolated from the nuclei of normal human and xeroderma pigmentosum complementation group A (XPA) cells, which recognizes predominately pyrimidine dimers, was examined for the mechanism by which it locates sites of damage on UVC-irradiated DNA. In reaction mixtures with low ionic strengths (i.e. lacking KCl), the normal and XPA endonuclease locate sites of UV damage on both naked and reconstituted nucleosomal DNA by different mechanisms. On both of these substrates, the normal endonuclease acts by a processive mechanism, meaning that it binds non-specifically to DNA and scans the DNA for sites of damage, whereas the XPA endonuclease acts by a distributive one, meaning that it randomly locates sites of damage on DNA. However, while both the normal and XPA endonucleases can incise UVC irradiated naked DNA, they differ in ability to incise damaged nucleosomal DNA. The normal endonuclease showed increased activity on UVC treated nucleosomal DNA compared with naked DNA, whereas the XPA endonuclease showed decreased activity on the damaged nucleosomal substrate. Since a processive mechanism of action is sensitive to the ionic strength of the micro-environment, the KCl concentration of the reaction was increased. At 70 mM KCI, the normal endonuclease switched to a distributive mechanism of action and its ability to incise damaged nucleosomal DNA also decreased. These studies show that there is a correlation between the ability of these endonucleases to act by a processive mechanism and their ability to incise damaged nucleosomal DNA; the normal endonuclease, which acts processively, can incise damaged nucleosomal DNA, whereas the XPA endonuclease, which acts distributively, is defective in ability to incise this substrate.

Regulatory intramolecular association in a tyrosine kinase of the Tec family

The T-cell-specific tyrosine kinase Itk is a member of the Tec family of non-receptor tyrosine kinases, and is required for signalling through the T-cell antigen receptor (TCR). The role of Itk in TCR signalling and the manner in which Itk activity is regulated are not well understood. Substrate binding and enzymatic activity of the structurally related Src kinases are regulated by an intramolecular interaction between the Src-homology-2 (SH2) domain and a phosphotyrosine. Although Itk also contains SH3, SH2 and tyrosine kinase domains, it lacks the corresponding regulatory phosphorylation site, and therefore must be regulated by an alternative mechanism. The proline-rich sequence adjacent to the SH3 domain of Tec family kinases contains an SH3 ligand, potentially allowing a different intramolecular interaction. By using multidimensional nuclear magnetic resonance we have determined the structure of a fragment of Itk, confirming that these domains interact intramolecularly. Formation of this intramolecular SH3-ligand complex prevents the Itk SH3 domain and proline-rich region from interacting with their respective protein ligands, Sam68 and Grb-2. We believe that this structure represents the first example of an intramolecular interaction between an SH3 domain and a proline-rich ligand, and has implications for the regulation of Tec family kinases.

Characterization of a 30-kDa Borrelia burgdorferi substrate-binding protein homologue

A Borrelia burgdorferi chromosomal gene encodes a 30-kDa antigen (P30) that has considerable homology with periplasmic substrate-binding proteins of Gram-negative bacteria, and is recognized by antibodies in sera from a subset of patients with Lyme disease and from B. burgdorferi-infected mice. The p30 gene is 801 nucleotides in length and P30 contains 267 amino acids, with a predicted molecular mass of 30 kDa. The P30 amino acid region 36-258 has homology to conserved domains of the oligopeptide permease A of Gram-negative bacteria. Immunofluorescence studies using murine anti-P30 serum suggest that P30 is on the outer surface of B. burgdorferi. P30 expression could be detected in representatives of all 3 subspecies of B. burgdorferi sensu lato, but not in all of the tested strains. Antibodies to P30 were detected in sera of 18 out of 82 patients (22%) with Lyme disease, including individuals with early- or late-stage infection. Although antibodies to P30 are present in the sera of C3H/HeN mice infected with B. burgdorferi for at least 90 days, immunization with recombinant P30 does not protect mice from infection. We conclude that P30 is a putative substrate-binding protein of B. burgdorferi and is immunologically recognized in human and murine Lyme borreliosis.

Cell-mediated immune response and T-like cells in thymectomized Oncorhynchus mykiss (Walbaum) infected with or vaccinated against the pathogenic haemoflagellate Cryptobia salmositica Katz, 1951

T-cell-mediated delayed-type hypersensitivity (TDTH) reaction was detected in Cryptobia salmositica-infected intact and thymectomized (2 months post-thymectomy) Oncorhynchus mykiss (Walbaum). Both groups of fish showed significant induration at the site of C. salmositica antigen injection at 8, 12 and 16 weeks post-infection. A significant difference was not observed in TDTH reactions between the thymectomized and intact (control) infected fish. The total numbers of circulating leucocytes detected in infected thymectomized fish were significantly lower than those found in infected shamthymectomized fish. The numbers of T-like cells determined (using alpha-naphthyl acid esterase assay) in thymectomized fish (9 months post-thymectomy) were similar to those seen in intact fish prior to and at 4 weeks after vaccination with an avirulent strain of C. salmositica. At 2 weeks after challenge with the pathogen the numbers of T-like cells in intact vaccinated fish increased significantly (P < 0.01) and remained high for the duration of the study (15 weeks). However, in vaccinated thymectomized fish the numbers of T-like cells remained low after parasite challenge. These results suggest that thymectomy in adult rainbow trout did not lower T-cell-mediated delayed-type hypersensitivity; however, it reduced the numbers of circulating leucocytes and retarded the proliferation of T-like cells after antigenic stimulation.

Molecular basis for the binding of SH3 ligands with non-peptide elements identified by combinatorial synthesis

BACKGROUND

Protein-structure-based combinatorial chemistry has recently been used to discover several ligands containing non-peptide binding elements to the Src SH3 domain. The encoded library used has the form Cap-M1-M2-M3-PLPPLP, in which the Cap and Mi's are composed of a diverse set of organic monomers. The PLPPLP portion provided a structural bias directing the non-peptide fragment Cap-M1-M2-M3 to the SH3 specificity pocket. Fifteen ligands were selected from > 1.1 million distinct compounds. The structural basis for selection was unknown.

RESULTS

The solution structures of the Src SH3 domain complexed with two ligands containing non-peptide elements selected from the library were determined by multidimensional NMR spectroscopy. The non-peptide moieties of the ligands interact with the specificity pocket of Src SH3 domain differently from peptides complexed with SH3 domains. Structural information about the ligands was used to design various homologs, whose affinities for the SH3 domain were measured. The results provide a structural basis for understanding the selection of a few optimal ligands from a large library.

CONCLUSIONS

The cycle of protein-structure-based combinatorial chemistry followed by structure determination of the few highest affinity ligands provides a powerful new tool for the field of molecular recognition.

Characterization of two genes, p11 and p5, on the Borrelia burgdorferi 49-kilo base linear plasmid

A putative operon encoding two Borrelia burgdorferi N40 genes, p11 and p5 was cloned and localized to the 49 kilobase linear plasmid. p11 encodes an 11 kDa protein and p5 encodes a 5 kDa protein. The first 88 nucleotides of p11 have 81% identity with orf5 on a circular plasmid from Borrelia afzelii strain Ip21, suggesting that homologues of these genes may be present in different regions of the B. burgdorferi genome.

Polymorphism of angiotensin I converting enzyme gene in the older Chinese: linked to ambulatory blood pressure levels and circadian blood pressure rhythm

This study was undertaken to evaluate the association of polymorphism of angiotensin I converting enzyme (ACE) gene with causal and ambulatory blood pressure in the Chinese population. Genomic DNA was amplified by polymerase chain reaction (PCR) using primers flanking the polymorphic region in intron 16 of the ACE gene. Alleles were detected on agarose gels stained with ethidium bromide. Causal blood pressure was measured in the 133 normotensive and 122 essential hypertensive subjects; of the essential hypertensive subjects, 65 patients underwent non-invasive ambulatory blood pressure. There was no significant difference of ACE genotype and allele frequencies between the hypertensive and normotensive subjects. Non-significant differences were demonstrated in gender, age, causal blood pressure according to the ACE gene genotypes in the 65 patients who underwent non-invasive ambulatory blood pressure; however, effects of the ACE gene genotypes were observed on the derivatives of ambulatory blood pressure, including sleeping blood pressure levels and circadian blood pressure rhythm (p < 0.05). We suggest that insertion/deletion polymorphism of the ACE gene should be associated with blood pressure and ambulatory blood pressure might be superior to causal blood pressure at the molecular level.

"Coulomb Staircase" at Room Temperature in a Self-Assembled Molecular Nanostructure

Double-ended aryl dithiols [alpha,alpha'-xylyldithiol (XYL) and 4,4'-biphenyldithiol] formed self-assembled monolayers (SAMs) on gold(111) substrates and were used to tether nanometer-sized gold clusters deposited from a cluster beam. An ultrahigh-vacuum scanning tunneling microscope was used to image these nanostructures and to measure their current-voltage characteristics as a function of the separation between the probe tip and the metal cluster. At room temperature, when the tip was positioned over a cluster bonded to the XYL SAM, the current-voltage data showed "Coulomb staircase" behavior. These data are in good agreement with semiclassical predictions for correlated single-electron tunneling and permit estimation of the electrical resistance of a single XYL molecule (approximately18 &plusmn; 12 megohms).

A tethered adhesive particle model of two-dimensional elasticity and its application to the erythrocyte membrane

A new model of two-dimensional elasticity with application to the erythrocyte membrane is proposed. The system consists of a planar array of self-adhesive particles attached to nearest neighbors with flexible tethers. Stretching from the equilibrium dimension is resisted because force is required to dissociate the particle clusters and to decrease the distribution entropy. Release of the external force is accompanied by a contraction as thermal diffusion randomizes the particles and allows interparticle attachments to form again. Analysis of membrane thermodynamics and mechanics under the two-state particle assumption results in a shear softening stress-strain relation. The shear modulus is found proportional to the square root of the surface density of particles, the interparticle adhesive energy, and is inversely proportional to the tether length. Applied to the erythrocyte membrane under the assumption that band 3 tetramer represents the particle and spectrin the tether, the shear modulus predicted corresponds to the measured value when the interparticle adhesive energy is approximately 4.0-5.9 kT, where kT is the Boltzmann constant multiplied by the temperature. This model suggests a mechanism wherein erythrocyte membrane deformability depends on integral protein homomultimeric interactions and can be modulated from the external surface.

Nuclear localization of a complex of fibroblast growth factor(FGF)-1 and an NH2-terminal fragment of FGF receptor isoforms R4 and R1alpha in human liver cells

FGF ligands and FGF receptor 1 (FGFR1) appear associated with the nucleus in addition to their extracellular and transmembrane locations. After receptor-dependent internalization in liver cells, radiolabeled 16-kDa FGF-1 appears in a 40-kDa covalent complex with a cellular protein. In this report, we show that in a human hepatoma cell line, HepG2, which expresses both FGFR4 and FGFR1, the 40-kDa complex cross-reacts with antibodies against the ectodomain of both types of receptors. In addition to antibody against FGF-1, a polyclonal antiserum against the three immunoglobulin (Ig)-like loop ectodomain of FGFR4 and a monoclonal antibody to a 19-residue sequence in the NH2-terminus of the NH2-terminal Ig Loop I of the three loop splice variant of FGFR1 (FGFR1alpha) reacts with the complex. A monoclonal antibody against an epitope in FGFR1 downstream of the inter-loop I/II sequence which reacts with intact FGFR1 failed to cross-react with the 40-kDa complex. Cell fractionations and indirect immunofluorescent localization revealed that the 40-kDa complex associates with the particulate fraction of cells, particularly the nucleus and associated cytoskeletal elements. We propose that the NH2-terminal Ig-loop of the three loop isoforms of FGFR, which are generally associated inversely with cell growth, may play a role at or in the nucleus in addition to modification of affinity of the FGFR ectodomain for heparan sulfate and FGF ligand.

P55, an immunogenic but nonprotective 55-kilodalton Borrelia burgdorferi protein in murine Lyme disease

Immunization of C3H mice with P55 (previously called S1), a 55-kDa Borrelia burgdorferi antigen that is immunogenic after infection, elicited a strong antibody response but did not protect mice against B. burgdorferi challenge. Mice immunized with a P55 fusion protein in complete Freund's adjuvant developed anti-P55 antibodies, detectable at a titer of 1:10,000 by immunoblotting. To determine, if a protective response had been elicited, P55-vaccinated mice were fed upon by ticks infected with B. burgdorferi. The frequency of B. burgdorferi infection was similar in P55-immunized and control mice, and spirochetes were not destroyed within ticks that fed on P55-vaccinated mice. P55 is an immunogenic antigen that does not induce a protective response in the vertebrate or invertebrate host.

Serum-mediated resolution of Lyme arthritis in mice

Arthritis and carditis were mildly improved upon adoptive transfer of T cell enriched lymphocyte populations from Borrelia burgdorferi-infected (B. burgdorferi) (immune) compared with naive immunocompetent mice into B. burgdorferi-infected, severe combined immunodeficient (SCID) mice. Despite the relative purity of T cells in transferred cells, recipient mice seroconverted to B. burgdorferi. Thus, the effect could not be attributed to T cells alone. Passive transfer of serum from actively infected immunocompetent mice (immune serum) to SCID mice at the time of or before B. burgdorferi inoculation, or on Days 4, 8, and 12 after inoculation prevented or cured (respectively) infection and disease when examined at 15 days. Transfer of immune serum on Days 12, 16, 20, 24, and 28 did not clear infection at Day 30 but resulted in resolution of arthritis, indicating that immune serum can cause resolution of joint disease. Immune serum treatment could maintain arthritis resolution for up to 60 days. Immune serum from mice infected for 90 days or 15 months both had strong protective, post-infection, and arthritis-modulating activity, whereas hyperimmune serum to heat-killed B. burgdorferi or recombinant outer surface protein (Osp) A protected mice against infection when given on Day 0--but not at later intervals--and did not modulate disease. Immune serum from 90-day infected mice labeled spirochetes in joint tissues of SCID mice by immunohistochemistry, but hyperimmune serum to heat-killed B. burgdorferi or OspA did not. These studies suggest that the biologically active properties of immune serum may be directed toward yet to be defined, in vivo-expressed antigens of B. burgdorferi.

Multichannel flow electrophoresis and its applications in purification of proteins, enzymes, and antibodies

Multichannel flow electrophoresis (MFE) is a novel preparative electrophoresis technique designed for continuous separation of proteins based on their different isoelectric points. A computer controlled MFE apparatus is developed and the effects of operation parameters such as electric field strength, buffering pH, and sample introducing flow rate on MFE separation efficiency are investigated. The application of MFE is first exemplified by continuous separation of BSA and HBB mixture. Then continuous purification of urokinase from urine extracts is conducted, in which 10 x 10(4) IU urokinase product whose specific activity is higher than 40,000 IU/mg is obtained per hour. Finally, MFE is applied in the continuous purification of anti-urokinase mouse IgG from mouse serum and yields 2.1 mg mouse IgG per hour with high purity demonstrated by SDS-PAGE. The preliminary results presented have confirmed the workability of MFE and pointed out its high application potential in biochemical process.

Specific interactions outside the proline-rich core of two classes of Src homology 3 ligands

Two dodecapeptides belonging to distinct classes of Src homology 3 (SH3) ligands and selected from biased phage display libraries were used to investigate interactions between a specificity pocket in the Src SH3 domain and ligant residues flanking the proline-rich core. The solution structures of c-Src SH3 complexed with these peptides were solved by NMR. In addition to proline-rich, polyproline type II helix-forming core, the class I and II ligands each possesses a flanking sequence that occupies a large pocket between the RT and n-Src loops of the SH3 domain. Structural and mutational analyses illustrate how the two classes of SH3 ligands exploit a specificity pocket on the receptor differently to increase binding affinity and specificity.

[Surgical treatment of craniosynostosis]

Craniosynostosis is the term that designates premature fusion of one or more cranial sutures that causes severe cranial deformities. The clinical features and the operative technique were introduced and the etiology and the key points for a successful operation were discussed in this paper.

[Survival rates in patients with systemic lupus erythematosus]

To assess the impact of demographic and clinical factors on prognosis in patients with systemic lupus erythematosus (SLE), we examined the survival rate by lifetable analysis in 566 patients. All patients were Shanghai citizens who were diagnosed as having SLE in Huashan Hospital between 1959 and 1992. According to American Rheumatism Association's preliminary criteria. The survival rate from the time of SLE onset was 93% at 1 year, 73% at 5 years and 60% at 10 years. On univariate analysis, we found that the following factors worsened the probability of survival; male, neuropsychiatric manifestation, pleurisy-pericarditis, anemia, thrombocytopenia, lymphocytopenia, proteinuria, hematuria, urinary cast, azotemia, decreased endogenous creatinine clearance, increased cholesterol in serum, hypocomplementemia, abnormal electrocardiograph and high corticosteroid dose of treatment. On multivariate analysis, we found the four independent risk factors were male, azotemia, hypocomplementemia and high corticosteroid dose of treatment.

Structure-function analysis of SH3 domains: SH3 binding specificity altered by single amino acid substitutions

SH3 domains mediate intracellular protein-protein interactions through the recognition of proline-rich sequence motifs on cellular proteins. Structural analysis of the Src SH3 domain (Src SH3) complexed with proline-rich peptide ligands revealed three binding sites involved in this interaction: two hydrophobic interactions (between aliphatic proline dipeptides in the SH3 ligand and highly conserved aromatic residues on the surface of the SH3 domain), and one salt bridge (between Asp-99 of Src and an Arg three residues upstream of the conserved Pro-X-X-Pro motif in the ligand). We examined the importance of the arginine binding site of SH3 domains by comparing the binding properties of wild-type Src SH3 and Abl SH3 with those of a Src SH3 mutant containing a mutated arginine binding site (D99N) and Abl SH3 mutant constructs engineered to contain an arginine binding site (T98D and T98D/F91Y). We found that the D99N mutation diminished binding to most Src SH3-binding proteins in whole cell extracts; however, there was only a moderate reduction in binding to a small subset of Src SH3-binding proteins (including the Src substrate p68). p68 was shown to contain two Arg-containing Asp-99-dependent binding sites and one Asp-99-independent binding site which lacks an Arg. Moreover, substitution of Asp for Thr-98 in Abl SH3 changed the binding specificity of this domain and conferred the ability to recognize Arg-containing ligands. These results indicate that Asp-99 is important for Src SH3 binding specificity and that Asp-99-dependent binding interactions play a dominant role in Src SH3 recognition of cellular binding proteins, and they suggest the existence of two Src SH3 binding mechanisms, one requiring Asp-99 and the other independent of this residue.

A 55-kilodalton antigen encoded by a gene on a Borrelia burgdorferi 49-kilobase plasmid is recognized by antibodies in sera from patients with Lyme disease

We have identified a 55-kDa antigen encoded by a gene on a 49-kb plasmid of Borrelia burgdorferi. The screening of a B. burgdorferi DNA expression library (N40 strain) with rabbit anti-B. burgdorferi serum and then with serum from a patient with Lyme disease arthritis revealed a clone that synthesized an antigen that was reactive with both sera. DNA sequence analysis identified an operon with two genes, s1 and s2 (1,254 and 780 nucleotides), that expressed antigens with the predicted molecular masses of 55 and 29 kDa, respectively. Pulsed-field gel electrophoresis showed that the s1-s2 operon was located on the 49-kb plasmid. Recombinant S1 was synthesized as a glutathione S-transferase fusion protein in Escherichia coli. Antibodies to recombinant S1 bound to a 55-kDa protein in lysates of B. burgdorferi, indicating that cultured spirochetes synthesized S1. Thirty-one of 100 Lyme disease patients had immunoglobulin G (IgG) and/or IgM antibodies to S1. IgG antibodies to S1 were detected by enzyme-linked immunosorbent assay and immunoblots in the sera of 21 (21%) of 100 patients with Lyme disease; 11 (27.5%) of the S1-positive samples were from patients (40) with early-stage Lyme disease, and 10 (16.7%) were from patients (60) with late-stage Lyme disease. Fifteen (38.5%) of 40 serum samples from patients with early-stage Lyme disease had IgM antibodies to S1. These data suggest that the S1 antigen encoded by a gene on the 49-kb plasmid is recognized serologically by a subset of patients with early- or late-stage Lyme disease.

Photon migration in the presence of a single defect: a perturbation analysis

We present an analytical perturbation analysis for studying the sensitivity of diffusive photon flux to the addition of a small spherical defect object in multiple-scattering media such as human tissues. As a first simple application of our perturbation method, we derive analytically the photon migration path distributions and the shapes of the so-called banana regions in which the photon migration paths are concentrated. We then derive analytically the sensitivity of detected photon flux densities to the inclusion of small spherical defects in the multiple-scattering medium for both single-source and two-source configurations, at both steady-state (dc) and frequency-modulation conditions, and compare the results with Monte Carlo simulations.

Lyme disease in human DR4Dw4-transgenic mice

The evolution of Lyme arthritis in DR4-transgenic mice infected with Borrelia burgdorferi was studied because chronic Lyme arthritis in humans is associated with an increased frequency of the HLA-DR4 allele. B10 nontransgenic and DR4-transgenic mice expressing chimeric human-mouse major histocompatibility complex class II genes in which the human alpha 1 and beta 1 domains of DR4Dw4 replaced the corresponding domains of the mouse I-E(d) were inoculated with B. burgdorferi and examined at up to 180 days for infection and disease. All mice were infected throughout the 180 days, and arthritis evolved to equal severity in transgenic and control mice within 30 days and resolved by day 120. Both groups of mice developed high antibody titers to B. burgdorferi, but antibodies to outer surface proteins A and B were not readily detectable. The DR4Dw4 transgene did not predispose mice to the development of chronic Lyme arthritis.

Two binding orientations for peptides to the Src SH3 domain: development of a general model for SH3-ligand interactions

Solution structures of two Src homology 3 (SH3) domain-ligand complexes have been determined by nuclear magnetic resonance. Each complex consists of the SH3 domain and a nine-residue proline-rich peptide selected from a large library of ligands prepared by combinatorial synthesis. The bound ligands adopt a left-handed polyproline type II (PPII) helix, although the amino to carboxyl directionalities of their helices are opposite. The peptide orientation is determined by a salt bridge formed by the terminal arginine residues of the ligands and the conserved aspartate-99 of the SH3 domain. Residues at positions 3, 4, 6, and 7 of both peptides also intercalate into the ligand-binding site; however, the respective proline and nonproline residues show exchanged binding positions in the two complexes. These structural results led to a model for the interactions of SH3 domains with proline-rich peptides that can be used to predict critical residues in complexes of unknown structure. The model was used to identify correctly both the binding orientation and the contact and noncontact residues of a peptide derived from the nucleotide exchange factor Sos in association with the amino-terminal SH3 domain of the adaptor protein Grb2.

Effect of 24-h blood pressure levels and circadian blood pressure rhythm on left ventricular structure and function in isolated systolic hypertension

Forty-one participants (mean age 69 +/- 5.6 years) were examined by fully automatic blood pressure monitor and Doppler echocardiography to gain information on the ambulatory blood pressure and the left ventricular structure and function in isolated systolic hypertension. Cumulative sum (cusum)-derived statistics was used to quantify circadian blood pressure rhythm and 24-h blood pressure levels were defined as mean blood pressure values during 24 h, waking (06:00-22:00 h) and sleeping (22:00-06:00 h) periods, respectively. Most of the derivatives of ambulatory blood pressure, including cusum-derived statistics and 24-h blood pressure levels, were significantly related with the left ventricular structural (left ventricular posterior wall and interventricular septum thickness) and functional (acceleration time in the left ventricular outflow tract and early diastolic deceleration time) indexes. Among the left ventricular structural and functional indexes, interventricular septum thickness at end diastole had the strongest correlation with sleeping diastolic mean blood pressure (r = 0.41, P < 0.01), left ventricular posterior wall at end diastole, the best with 24-h systolic mean blood pressure (r = 0.41, P < 0.01), acceleration time the strongest with systolic cusum-derived circadian alteration magnitude (r = 0.49, P < 0.01) and early diastolic deceleration time the greatest with diastolic cusum-derived trough blood pressure (r = 0.45, P < 0.01). We conclude that left ventricular structural changes rely on 24-h systolic and diastolic blood pressure levels, whereas left ventricular functional variations may be more dependent upon circadian blood pressure rhythm in elderly patients with isolated systolic hypertension.

Vertical Aluminophosphate Molecular Sieve Crystals Grown at Inorganic-Organic Interfaces

Tubular aluminophosphate molecular sieve crystals were grown at an organic interface with their channels (7 angstroms in cross section) vertical to the substrate. To induce surface nucleation and oriented growth of AIPO(4)-5 crystals, organophosphonate layers cross-linked with Zr(IV) were assembled on a gold substrate and the modified substrate was immersed in a hydrothermal bath containing reagents for the synthesis of the molecular sieve. Reflection-absorption infrared studies demonstrated the stability of the phosphonate layers under these conditions. Drastic changes in the morphology of the surface-grown crystals from spherical agglomerates to vertical needles to thin tilted needles could be achieved by adjusting the water content of the synthesis bath. Nitrogen sorption in these structures on a piezoelectric device confirmed the presence of zeolitic microporosity.

[Surgical treatment of orbital fracture]

In last six years, 51 cases (34 males, 17 females) of orbital deformities caused by fracture were treated. According to careful examinations, x-ray and CT scan, the operation plan was made. The coronal incision or plus lower eyelid incision were employed. Subperiosteal dissection began from the upper margin of the orbit to release input soft tissue and reposition the eyeball. Rib bone was grafted for orbital defects. Canthoplasty was used if necessary. The surgical results were satisfactory.

[Mandibular advancement for the treatment of micrognathia with obstructive sleep apnea]

Fifteen patients with micrognathia and obstructive sleep apnea syndrome (OSAS) are presented. All patients were evaluated before and after surgery by physical examinations, cephalometric, fibroptic pharyngoscopy and oxygen saturation (SaO2). A method that allows isolated advancement of the genial tubercle and genioglossus muscle is described. The operation could enlarge the pharyngeal airway space at the base of the tongue (P < 0.05), increase SaO2 and decrease MP-H (P < 0.05) so that the symptoms of OSAS improved or disappeared. The facial symmetry and chin prominence also improved significantly. This method is simple and effective for the treatment of OSAS due to micrognathia and obviates the need for intermaxillary fixation. But it is not indicated for patients with severe malocclusion or airway obstruction on more than one sites.

Structural basis for the binding of proline-rich peptides to SH3 domains

A common RXL motif was found in proline-rich ligands that were selected from a biased combinatorial peptide library on the basis of their ability to bind specifically to the SH3 domains from phosphatidylinositol 3-kinase (PI3K) or c-Src. The solution structure of the PI3K SH3 domain complexed to one of these ligands, RKLPPRPSK (RLP1), was determined. Structure-based mutations were introduced into the PI3K SH3 domain and the RLP1 ligand, and the influence of these mutations on binding was evaluated. We conclude that SH3 domains recognize proline-rich motifs possessing the left-handed type II polyproline (PPII) helix conformation. Two proline residues directly contact the receptor. Other prolines in the ligands appear to function as a molecular scaffold, promoting the formation of the PPII helix. Three nonproline residues consisting of combinations of arginine and leucine interact extensively with the SH3 domain and appear to confer ligand specificity.