Human interferon-beta inhibits binding of HIV-1 gp41 to lymphocyte and monocyte cells and binds the potential receptor protein P50 for HIV-1 gp41

Previous findings have indicated that HIV-1 gp41 like human type I interferon (IFN) could inhibit lymphocyte proliferation and up-modulate MHC class I, II and ICAM-1 molecule expression, and a common epitope exists between gp41 and type I interferon (IFN-alpha and -beta) in the receptor binding regions. To clarify the relationship between human type I interferon and HIV-1 gp41, we tried to inhibit recombinant soluble gp41-binding to human T, B and monocyte cell lines by human IFN-alpha, -beta and -gamma. It was interestingly observed that IFN-beta after preincubating with cells could inhibit the binding of rsgp41 to H9, Raji and U937 cells (T, B and monocyte cell lines), while this binding could not be inhibited by another type I interferon (IFN-alpha) and a type II interferon (IFN-gamma). It was further examined whether human IFN-alpha and -beta bind to the gp41 binding protein P50. In ELISA-assay, the human IFN-beta, but not IFN-alpha, could bind to P50 which was identified as a potential cellular receptor protein for gp41-binding. By the affinity capillary electrophoresis (ACE) analysis, formation of stable IFN-beta-P50 complex was observed. These results indicate that IFN-beta binds the potential receptor protein P50. Based on these experimental evidences and previous studies, it was presumed that the potential cellular receptor protein P50 may be the 51 kDa subunit of human IFN-alpha/beta receptor, which needs to be verified in the future.

[Synthesis and identification of methylparathion artificial antigen]

In order to synthesize the artificial antigen methylparathion(M1605), methylparathion was reduced into amino-methylparathion by using acetic acid-zinc powder-hydrochloric acid. Artificial antigens (M1605-BSA, M1605-TTH) were synthesized by conjugating amino-methylparathion to bovine serum albumin(BSA) and tachypleus tridentatus hemocyanin (TTH) directly after diazotization. Rabbits were immunized with M1605-BSA for 10 weeks, and the high titer and high specificity antiserum from those rabbits was testified by double agar gel diffusion and indirect ELISA. The results showed that an artificial antigen was obtained successfully and this made it possible to establish the immunoassay of M1605.

Primary isolation of Ehrlichia chaffeensis from patients with febrile illnesses: clinical and molecular characteristics

Ehrlichia chaffeensis was sought among patients with a history of tick exposure and fever, and the accuracy of other diagnostic tests was compared with that of primary isolation. Among the 38 patients enrolled, E. chaffeensis was isolated from the blood of 7 (18%) and from cerebrospinal fluid specimens of 2 of these 7. All 7 patients also were positive by polymerase chain reaction (PCR) of blood, and 6 patients developed diagnostic titers of antibody to E. chaffeensis. The isolates were characterized by molecular analysis of the 16S rRNA gene, the 120-kDa protein gene, and the variable-length PCR target (VLPT) of E. chaffeensis. On the basis of the 120-kDa and VLPT genotypes, the cerebrospinal fluid and blood isolates from the same patients were identical. This study demonstrates that both PCR and culture of blood for E. chaffeensis have high diagnostic yields. More frequent isolation of E. chaffeensis from patients with infection should further our understanding of the pathogenesis of this infection.

Antibodies to HIV-1 gp41 recognize synthetic peptides of human IFN-alpha and IFN-beta

Based on our finding that a common epitope exists between HIV-1 gp41 and human type I interferons (IFN-alpha and IFN-beta), and increased levels of antibodies against human IFN-alpha and IFN-beta were observed in HIV-1-infected individuals, we tried to explain the mechanism of increased levels of antibodies. Mouse antisera recognizing HIV-1 recombinant soluble (rs) gp41 (aa 539-684) interacted with two synthetic peptides sequence-corresponding to the IFN-alpha/beta receptor binding site on human IFN-alpha and IFN-beta, while normal mouse serum (pooled normal sera) did not. The anti-rspg41 antisera after adsorption by IFN-beta sepharose column lost the activity of interaction with both synthetic peptides. In another experiment, rsgp41 could bind to sepharose column conjugated with anti-IFN-beta polyclonal antibodies (IgG). These results indicate that the common epitope on gp41 and type I interferons could induce antibodies recognizing the receptor binding site on IFN-alpha and IFN-beta, suggesting that increased levels of antibodies against IFN-alpha and IFN-beta in HIV-1-infected individuals could be induced by gp41.

Nonlinear behavior of vocal fold vibration: the role of coupling between the vocal folds

Coupling between the vocal folds is one of the nonlinear mechanisms allowing regulation and synchronization of mucosal vibration. The purpose of this study was to establish that modulations such as diplophonia and abnormalities observed in vocal signals that may be observed in some cases of laryngeal pathology can be considered as nonlinear behavior due to the persistence of some physical interaction (coupling). An experimental model using excised porcine larynx was designed to create tension asymmetry between the vocal folds and to obtain vocal signals with modulations. Signals were analyzed by spectral analysis and the phase portrait method. Results were compared with computer-generated synthetic signals corresponding to nonlinear combinations of sinusoid signals. Under these conditions, evidence of nonlinear behavior was detected in 85% of experimental signals. These findings were interpreted as a demonstration of vocal fold interaction. Based on these findings, the authors conclude that (1) coupling must be taken into account in physical models of laryngeal physiology, and that (2) methods of nonlinear dynamics may be used for objective voice analysis.

Studies on treatment of acute promyelocytic leukemia with arsenic trioxide: remission induction, follow-up, and molecular monitoring in 11 newly diagnosed and 47 relapsed acute promyelocytic leukemia patients

Fifty-eight acute promyelocytic leukemia (APL) patients (11 newly diagnosed and 47 relapsed) were studied for arsenic trioxide (As2O3) treatment. Clinical complete remission (CR) was obtained in 8 of 11 (72.7%) newly diagnosed cases. However, As2O3 treatment resulted in hepatic toxicity in 7 cases including 2 deaths, in contrast to the mild liver dysfunction in one third of the relapsed patients. Forty of forty-seven (85.1%) relapsed patients achieved CR. Two of three nonresponders showed clonal evolution at relapse, with disappearance of t(15;17) and PML-RARalpha fusion gene in 1 and shift to a dominant AML-1-ETO population in another, suggesting a correlation between PML-RARalpha expression and therapeutic response. In a follow-up of 33 relapsed cases over 7 to 48 months, the estimated disease-free survival (DFS) rates for 1 and 2 years were 63.6% and 41.6%, respectively, and the actual median DFS was 17 months. Patients with white blood cell (WBC) count below 10 x 10(9)/L at relapse had better survival than those with WBC count over 10 x 10(9)/L (P =.038). The duration of As2O3-induced CR was related to postremission therapy, because there was only 2 of 11 relapses in patients treated with As2O3 combined with chemotherapy, compared with 12 of 18 relapses with As2O3 alone (P =.01). Reverse transcription polymerase chain reaction (RT-PCR) analysis in both newly diagnosed and relapsed groups showed long-term use of As2O3 could lead to a molecular remission in some patients. We thus recommend that ATRA be used as first choice for remission induction in newly diagnosed APL cases, whereas As2O3 can be either used as a rescue for relapsed cases or included into multidrug consolidation/maintenance clinical trials.

Two proteins share immunological epitopes on the tumor-associated antigen 17-1A

The mouse monoclonal antibody (mAb) 17-1A which recognizes the tumor-associated antigen 17-1A (also called EGP-40 or EpCAM) was successfully used in adjuvant therapy for colorectal carcinoma. In the 17-1A antigen analysis, we isolated not only a protein of 33 kDa (P33) which was reported as the tumor associated antigen 17-1A, but also a protein of 65 kDa (P65) using affinity chromatography from cell lysates of HCT, and another protein of 50 kDa (P50) from lysates of human colorectal tumor tissues. The mAbs 17-1A and M79 (mAb M79 recognizes a different epitope on the 17-1A antigen) both could bind P33 and P50, but only M79 bound to P65 in an enzyme-linked immunosorbant assay (ELISA). These results indicate that P33 and P50 share at least two epitopes, and a common immunological epitope exists among P33, P50 and P65, suggesting that the two new proteins (P50 and P65) are related to the tumor-associated antigen 17-1A.

Catalytic asymmetric allylation reactions using BITIP catalysis and 2-substituted allylstannanes as surrogates for beta-keto ester dianions

[formula: see text] Catalytic asymmetric allylation (CAA) reactions using the indicated allylstannane and the BITIP catalysts previously described by us give high yields and enantioselectivities in additions to aldehydes. The products are convertible to beta-keto esters by oxidative cleavage of the olefin. These reactions thus provide a useful catalytic enantioselective method for chain extension with introduction of a versatile four-carbon unit.

[Time trend of mortality rates of cerebrovascular diseases in Hong Kong]

OBJECTIVE

To describe the time trend of mortality rates of cerebrovascular diseases (CVD) in Hong Kong for the period of 1976 to 1995, and to compare them with those in the more developed countries around the world.

METHODS

Mortality rates of CVD were standardized directly using world standard population in 1961. Annual percent changes of mortality rates of CVD were estimated with a non-linear regression. Birth-cohort analysis was carried out at an interval of five-year of age to compare their age-specific mortality rates of CVD in different birth cohorts. Time trend of cause-specific mortality rates of CVD both in males and females was fitted with a simple linear regression model.

RESULTS

Considerable downward trend of CVD mortality was observed during the past twenty years. Mortality rates among men and women decreased by 50.96% and 37.85% in 1995, as compared to those in 1976, respectively. Although in general, a greater trend in CVD mortality was observed during the last 10 years, as compared with that in the previous 10 years, an annual increase in CVD mortality of 1.34% was found among males aged 35 to 44 years during the latter 10 years. CVD mortality for both males and females decreased steadily by 1% per year. CVD mortality for females will catch up with that for males by the year of 2013, if such a trend continues. Birth-cohort analysis showed that those born more recently at the same age-group had lower mortality of CVD (except for those born after 1955). Data from hospital admission showed that improvement in the treatment for CVD could have contributed partly to the decrease in its mortality.

CONCLUSION

Time trend of mortality of CVD in Hong Kong was similar to that in many other economically developed areas around the world.

[The diagnostic significance of antineutrophil cytoplasmic antibodies in ulcerative colitis]

OBJECTIVE

To inquire into the diagnostic significance of antineutrophil cytoplasmic antibodies (ANCA) in ulcerative colitis (UC).

METHODS

Serum ANCA from 58 UC patients, 43 non-UC patients and 58 healthy donors were detected with indirect immunofluorescence (IIF), enzyme linked immunosorbent assay (ELISA)and Western blot.

RESULTS

The sensitivity and specificity of the presence of ANCA in the diagnosis of UC were 37.93% and 100% respectively. In the group of UC, patients with mild, moderate and severe clinical manifestations had positive ANCA rates of 17.65%, 41.67% and 52.94% respectively. The occurrence rates of mucosal vasculitis and grade III-V mucosal inflammation were 78.95% and 78.95% respectively in ANCA-positive group, but 37.04% and 44.44% in ANCA-negative group. The levels of the binding of the five kinds of ANCA antigens i.e. myeloperoxidase (MPO), bactericidal/permeability increasing protein (BPI), lactoferrin (LF), cathepsin G (CG) and proteinase-3 (PR-3) with the serum of UC patients were 13.99%, 13.79%, 10.34% 10.34% and 8.62% respectively. Specific protein strips were observed in 48.28% of the UC patients with Western blot technique, 47,000 polypeptide being the most common and making up 22.41% of them.

CONCLUSION

The detection of ANCA was an auxiliary method for the diagnosis of UC. At present, UC-associated target antigens were not yet clarified, 47,000 polypeptide may be one of them. ANCA may participate in the pathogenesis of UC.

A high dose of ionizing radiation induces tissue-specific activation of nuclear factor-kappaB in vivo

Activation of the transcription factor nuclear factor-kappaB (NF-kappaB) is one of the important responses of cells to an external stress such as ionizing radiation. We studied radiation-induced NF-kappaB activation in vivo in male BALB/c mice. After the mice were exposed to 8.5 Gy total-body gamma irradiation, the spleen, mesenteric lymph nodes, thymus, liver, lung, colon, brain and bone marrow were harvested 1, 2.5, 5, 10 and 20 h postirradiation. NF-kappaB DNA-binding activity was analyzed in the nuclear protein extracts by a gel shift assay. When compared to the levels in untreated control mice, radiation induced activation of NF-kappaB in spleen, mesenteric lymph nodes and bone marrow but not in the other tissues examined. In contrast, an i.p. injection of a lethal dose (3 mg/kg) of lipopolysaccharide also increased activity of NF-kappaB in the liver and lung. The gel supershift assay with Nfkb1, Rela and/or Rel antibodies revealed that the specific molecular forms of NF-kappaB activated by radiation in the spleen were Nfkb1 homodimers and Nfkb1/Rela heterodimers. In mesenteric lymph nodes, the heterodimerized Rel/Rela NF-kappaB was also activated. In bone marrow, an NF-kappaB-like binding factor was induced that may be Nfkb1/Rela- and Rel/Rela-like heterodimers, but it exhibited a higher mobility than Nfkb1 homodimers. These results indicate that in vivo, ionizing radiation induces NF-kappaB activation that varies in both tissue distribution and moleoular composition.

[Fluorescence study on the interaction of salicylic acid and human serum albumin]

The change in fluorescence of human serum albumin (HSA) and salicylic acid due to their interaction has been studied in 0.05 mol/L, pH 9.50 borate buffer (contains 0.01 mol/L KCl). The dissociation constant of salicylic acid from HSA was obtained by using two different methods.

Adaptation of very virulent infectious bursal disease virus to chicken embryonic fibroblasts by site-directed mutagenesis of residues 279 and 284 of viral coat protein VP2

The full-length RNA genomes of a chicken embryonic fibroblast (CEF)-nonpermissive, very virulent infectious bursal disease virus (IBDV) (strain HK46) were amplified into cDNAs by reverse transcription-PCR. The full-length cDNAs were sequenced and subcloned into a eukaryotic expression vector, from which point mutations were introduced into the VP2 region by site-directed mutagenesis. The wild-type and mutated plasmids were transfected directly into CEFs to examine their ability to generate CEF-permissive recombinant viruses. Substitution of amino acid residues 279 (Asp-->Asn) and 284 (Ala-->Thr) of the VP2 protein yielded a recombinant virus which was able to be passaged in CEFs, whereas the wild-type cDNAs and an amino acid substitution at residue 330 (Ser-->Arg) of the VP2 protein alone did not yield viable virus. The results indicated that mutation of other viral proteins, including VP1, VP3, VP4, and VP5, was not required for CEF adaptation of the virus. The same approach may be used to produce CEF-adapted strains from newly evolved IBDVs or to manipulate the antigenicity of the virus.

Control of 3' splice site choice in vivo by ASF/SF2 and hnRNP A1

The constitutive splicing factor ASF/SF2 has been shown to affect the choice between alternative splice sites by favoring the proximal as opposed to the distal choice. HnRNP A1 antagonizes ASF/SF2 by promoting the distal choice for competing 5' splice sites. We have tested the in vivo effects of these proteins on alternative 3' splice site choices. Cotransfection of a dihydrofolate reductase-calcitonin chimeric construct togetherwith a plasmid specifying the SR protein ASF/SF2 into cells of several mammalian lines increased use of a proximal 3' splice site, resulting in the inclusion of a terminal calcitonin exon. This stimulation of 3' proximal splicing was antagonized by cotransfection with an hnRNP A1 plasmid. This effect of hnRNP A1 in promoting distal splicing was also seen in an hnRNP A1-deficient MEL cell line. A similar effect of hnRNP A1 was demonstrated with mutant hamster adenine phosphoribosyltransferase (aprt) transcripts that are normally constitutively spliced, suggesting that hnRNP A1 may be a general inhibitor of proximal splicing. Intron size also influenced splice site choice in mutant aprt transcripts, with larger introns favoring proximal splicing. These results support the idea that the ratios of particular but general splicing factors and hnRNPs play a role in alternative splicing.

Solution structure of a fragment of the dimerization domain of DP-1 determined by 1H-nuclear magnetic resonance and distance geometry

The structure of a synthesized peptide with the sequence of NHILPNESAYDQKNIRRRVYDALNVLMAMNIISK that corresponds to residues 151-184 of transcription factor DP-1 (Girling et al., Nature 362 (1993) 83-87) was determined by 1H-nuclear magnetic resonance in water and 40% d3-trifluoroethanol/water, respectively. Nuclear Overhauser effect cross peaks, alphaH chemical shifts and J-coupling constants of alphaH-NH show that the peptide consists a helix from Ser-8 to Ser-33 in solution. Fifty structures were constructed with 288 upper distance limits and 21 angle constraints by DIANA (Guntert et al., J. Mol. Biol. 217 (1991) 517-530). Although the N-terminal of the peptide exhibits a random conformation, the 20 best structures show a root mean square deviation of 0.89+/-0.36 A for backbone atoms and 1.80+/-0.34 A for heavy atoms from residue Ser-8 to Ser-33. This result supports the proposal that DP-1 and E2F-1 may dimerize with a coiled-coil type interaction.

[The fluorescence properties of DaYaWan soil humic acid]

The fluorescence properties of humic acid derived from DaYaWan soil were analyzed using the conventional fluorescence and synchronous scan fluorescence spectroscopy. The results show that synchronous technique applied to the study of humic acid can reduce the fluorescence spectrum of a compound to a single sharp peak, and decrease the signal overlapping. In addition, the effects of various deltalambda, concentration and pH values on synchronous fluorescence spectroscopy were investigated in detail.

Vitamin D receptor alleles predict growth and bone density in girls

OBJECTIVES

Polymorphism of the vitamin D receptor (VDR), collagen alpha I type I (Col I alpha I), and oestrogen receptor (ER) genes have been shown to account for some of the heritability of bone mineral density (BMD) in adults. This study examined this relation in prepubertal children.

METHODS AND SUBJECTS

The relation between genotypes of VDR gene (Taq I, Bsm I, Fok I), Col I alpha I gene (Msc I), and ER gene (Pvu II) with areal BMD, volumetric BMD, and growth were examined in 114 (68 girls) healthy 7 year old, white children.

RESULTS

The genotype of the VDR gene (Taq I) correlated with lumbar spine (L1-4) volumetric BMD in girls only, but at no other bone sites. In girls, VDR genotype affected areal BMD at all sites. After adjusting for height and weight, however, this effect was explained completely by the independent effect of the VDR genotype on growth. Girls with genotype TT, were 3.9 kg heavier and 4.1 cm taller than those with tt, but this relation was not present at birth. No relation was found between genotypes of the VDR gene (Fok I), Col I alpha I gene (Msc I), or ER gene (Pvu II) and BMD or growth variables.

CONCLUSIONS

In prepubertal girls, VDR alleles contribute to lumbar spine volumetric BMD variance, but the areal BMD effect reflects the relation between areal BMD and growth. VDR alleles might affect postnatal growth regulation.

Mammography spectrum measurement using an x-ray diffraction device

The use of a diffraction spectrometer developed by Deslattes for the determination of mammographic kV is extended to the measurement of accurate, relative x-ray spectra. Raw x-ray spectra (photon fluence versus energy) are determined by passing an x-ray beam through a bent quartz diffraction crystal, and the diffracted x-rays are detected by an x-ray intensifying screen coupled to a charge coupled device. Two nonlinear correction procedures, one operating on the energy axis and the other operating on the fluence axis, are described and performed on measured x-ray spectra. The corrected x-ray spectra are compared against tabulated x-ray spectra measured under nearly identical conditions. Results indicate that the current device is capable of producing accurate relative x-ray spectral measurements in the energy region from 12 keV to 40 keV, which represents most of the screen-film mammography energy range. Twelve keV is the low-energy cut-off, due to the design geometry of the device. The spectrometer was also used to determine the energy-dependent x-ray mass attenuation coefficients for aluminium, with excellent results in the 12-30 keV range. Additional utility of the device for accurately determining the attenuation characteristics of various normal and abnormal breast tissues and phantom substitutes is anticipated.