Longitudinal study of molecular epidemiology of small round-structured viruses in a pediatric population

Small round-structured viruses (SRSV), recently designated members of the family Caliciviridae, can now be readily subtyped by amplification of a defined portion of their genome by reverse transcription-PCR and then by identification of the amplicons with specific probes by Southern blotting. A longitudinal survey (from 1991 to 1995) was conducted to determine the genotypes of the SRSV present in pediatric stool specimens from patients with sporadic cases of gastroenteritis. It was found that almost all viruses were of the G-2 genotype, and on probing, the subtype P2-B was predominant but the frequencies of the different subtypes varied from year to year. A survey of the genotypes of SRSV from community outbreaks from 1995 showed that the G-2 genotype was also predominant and that the distribution of its subtypes was similar to that seen in sporadic cases of diarrhea in pediatric patients over the same time period. It was concluded that there is a succession of subtypes of SRSV in our pediatric population over time. This distribution of genotypes in sporadic cases of pediatric gastroenteritis may reflect the distribution in community outbreaks occurring at the same time.

Effect of an annular pupil on confocal imaging through highly scattering media

We report on confocal scanning imaging through highly scattering media. Various practical effects including those of the annular pupils and the size of the confocal pinhole as well as of the numerical aperture of objectives on the image quality are examined xperimentally. The combination of an annular objective with a finitesized detector may prove advantageous for improving image quality.

Mitochondrial defect in Huntington's disease caudate nucleus

Although the Huntington's disease (HD) gene defect has been identified, the structure and function of the abnormal gene product and the pathogenetic mechanisms involved in producing death of selective neuronal populations are not understood. Indirect evidence from several sources indicates that a defect of energy metabolism and consequent excitotoxicity are involved in HD. Toxin models of HD may be induced by 3-nitropropionic acid or malonate, both inhibitors of succinate dehydrogenase, complex II of the mitochondrial respiratory chain. We analyzed mitochondrial respiratory chain function in the caudate nucleus (n = 10) and platelets (n = 11) from patients with HD. In the caudate nucleus, severe defects of complexes II and III (53-59%, p < 0.0005) and a 32-38% (p < 0.01) deficiency of complex IV activity were demonstrated. No deficiencies were found in platelet mitochondrial function. The mitochondrial defect identified in HD caudate parallels that induced by HD neurotoxin models and further supports the role of abnormal energy metabolism in HD. The relationship of the mitochondrial defect to the role of huntingtin is not known.

Furin regulates both the activation of Pseudomonas exotoxin A and the Quantity of the toxin receptor expressed on target cells

Pseudomonas exotoxin A (PE) binds and enters mammalian cells via the alpha 2-macroglobulin receptor/low density lipoprotein receptor-related protein (LRP). The toxin then requires proteolytic cleavage to generate an enzymatically active fragment with translocates to the cell cytosol and inhibits protein synthesis. To assess the role of furin in determining toxin susceptibility, CHO cells were transfected with a mouse furin gene (CHO+fur cells) and maintained under neomycin selection. Cells expressing the transfected gene were about two- to threefold more sensitive to PE than were cells expressing only a neomycin resistance gene (CHO+neo cells). Possible reasons for the increased toxin sensitivity include the cleavage of a greater number of PE molecules and/or the conversion of more single-chain LRP to the processed, two-chain form. Processing of LRP appears to be necessary to allow the surface display of this receptor. Results of ligand binding studies indicated that the CHO+fur cells displayed about twofold more surface-expressed LRP than did CHO+neo cells. In addition, the in vitro cleavage of PE by recombinant furin enhanced toxin potency about threefold for CHO+neo cells but enhanced it very little for CHO+fur cells. This suggested that CHO+fur cells were processing PE at close to the maximum usable rate. Together these findings suggest that furin is involved in at least two separate protein processing pathways that each contribute to the sensitivity of cells to PE.

[The evaluation of adenosine triphosphate bioluminescence assay for chemosensitivity testing of ovarian cancer cell line]

OBJECTIVE

To assess the efficacy of adenosine triphosphate (ATP) assay for chemosensitity testing of ovarian cancer cell line and to compare its predicting value with that of diphenyltetrazolium bromide (MTT) test.

METHODS

By using ATP assay and MTT test the cytotoxic effect of 7 anticancer drugs on ovarian cancer cell line AO were determined. The sensitivity and stability of ATP assay were compared with those of MTT test. The optimal time of exposure of the cells to the drugs before doing ATP chemosensitity assay is investigated.

RESULTS

(1) The results obtained by ATP assay correlate well with that by MTT test (r = 0.918 1). However, in 90% of the assay samples the cytotoxic effect of the chemotherapeutic agents on cancer cells detected by ATP assay was 10% or more stronger as compared with that determined by MTT test. The difference in sensitivity of the two assays was also demonstrated by the least number of living cells. A change of living cells of 60 per well could be detected by ATP assay while that detected by MTT test should be 200 per well. (2) By repeating the tests of a same batch of samples for 5 times, it revealed that the results obtained by ATP assay was more stable than MTT test. The difference between the sx- (standard error) of the two tests was significant (P < 0.05). (3) The optimal time of exposure of the cancer cells to the anticancer drugs for testing its chemosensitivity was 5 days.

CONCLUSIONS

The method of ATP assay for chemosensitivity test is simple and convenient with high sensitivity and stability. It may be used as a new in vitro chemosensitivity test in patients with ovarian cancer.

Mutational spectra in the lacl gene in skin from 7,12-dimethylbenz[a]anthracene-treated and untreated transgenic mice

Transgenic mice carrying the bacterial lacl gene in a lambda shuttle vector were used to isolate and characterize background and 7,12-dimethylbenz[a]anthracene (DMBA)-induced mutations in skin. Adult male mice were treated once topically with either DMBA or acetone or were left untreated. Seven days later, DMBA treatment had significantly increased the mutant frequency in the skin (mean +/- SEM, 36 +/- 3 x 10(-5)) versus in vehicle-treated (6.4 +/- 1.2 x 10(-5)) and untreated mice (7.1 x 1.0 x 10(-5)). At least 10 mutants from each of three DMBA-treated and three untreated mice were selected for DNA sequence analysis. In each case, the entire 1080-bp target gene was sequenced. Base-pair substitutions predominated (86 of 96 mutations), although frameshift and deletion mutations were also detected. Twelve percent of the mutants carried more than one mutation. In controls, the mutations were predominantly GC-->AT transitions (26 of 42), and no AT-->TA transversions were recovered. In contrast, in the DMBA-treated mice, AT-->TA transversions represented 42% of the mutations (23 of 54) and GC-->AT transitions accounted for only 11%. The AT-->TA transversions occurred mostly at 5'-CA sites. This class of mutation has been recovered frequently in ras genes from DMBA-treated mice and probably represents an early event in carcinogenesis (Nelson MA et al., Proc Natl Acad Sci USA 89:6398-6402, 1992). Our present results are consistent with the types of DNA damage induced by DMBA. The observation of different mutant frequencies and spectra in treated and control mice demonstrates the utility of this approach in the study of mutagenesis in vivo.

[A study on the relationship between cervical carcinoma, dysplasia and sexually transmitted diseases]

OBJECTIVE

To reveal the relationship between cervical carcinoma, dysplasia and infections of human papillomavirus (HPV) and/or chlamydia trachomatis (CT).

METHODS

Indirect immunoperoxidase assay (IPA) was used in 99 patients with cervical lesions to test the specific antibody to CT in serum. At the same time, HPV in biopsies was determined from 40 patients with or without CT infection by using polymerase chain reaction (PCR).

RESULTS

(1) CT infection was found in a significantly greater proportion in women suffering from cervical carcinoma (61.5%) and dysplasia (83.3%) than in those of the control group (39.5%) (P < 0.01). (2) Under colposcopy, the incidence of white epithelium in patients suffering from dysplasia was 28.6% (12/42) in the CT positive group, while in the CT negative group the incidence was 6.5% (2/31). The incidence of white epithelium in patients with both CT and HPV infections was higher than that in patients with CT infection alone. (3) In CT positive group, the incidence of HPV in patients suffering from cervical cancer and from dysplasia (60%) was much higher than that in the CT negative group (10%).

CONCLUSIONS

CT and HPV-infections play a synergetic role in the etiology of cervical cancer.

[Human basophil degranulation test (HBDT) in fungal allergic asthmatic patients]

The authors recommand the methodology of HBDT for testing fungal allergens, pH 7.6, 37 degrees C and 10 mg/ml are the most suitable experimental conditions. The positive rate of HBDT in allergic asthmatic patients is 91.7%, and correlated very well with the results of skin tests. The degranulation index (DI) in allergic asthma is significantly higher than that in normals (P < 0.001). The DI after one year's desensitization treatment with fungal allergens is markedly lowered than before (P < 0.001). The results suggest that HBDT is a simple, reliable and precise method to investigate allergens in vitro and also reflects the function of basophils in asthma.

Furin is important but not essential for the proteolytic maturation of gp160 of HIV-1

The envelope glycoproteins of HIV are required for viral infectivity. Proteolysis of the precursor envelope glycoprotein gp160 results in the formation of gp120 and gp41. Cleavage occurs after the sequence Arg-Glu-Lys-Arg. This sequence is expected to be a substrate for the cellular protease furin. We examined whether furin is responsible for cleavage of gp160 by using a furin-deficient CHO cell line and the same cell line transfected with furin cDNA. Data obtained from viral transmission assays suggested that furin increased viral infectivity but was not essential for the maturation of gp160, implying that other proprotein processing enzymes also recognize this putative furin cleavage site.

Identification of salivary proteins inhibiting herpes simplex virus 1 replication

Salivary proteins play an important role in the maintenance of the oral ecology. Previous studies have indicated that human submandibular-sublingual and parotid salivas can selectively suppress the in vitro infectivity of herpes simplex virus 1. The purpose of this study was to identify the salivary components in human submandibular-sublingual saliva that modulate in vitro infectivity. Assessment of the interaction of viral particles with salivary components was accomplished using an in vitro solid-phase assay. These experiments revealed that herpes simplex virus particles selectively interact with the members of the salivary proline-rich protein and cystatin families. Subsequent yield reduction assays demonstrated the ability of proline-rich proteins and salivary cystatins to inhibit the viral replication, with basic proline-rich peptides being more effective. Subsequent assays suggest that basic proline-rich peptides reduced the virus titer by interfering with penetration and/or cellular processing of virus within the target cell. Collectively, these results further suggest that salivary proteins have an important role in the host defense mechanism against recurrent herpesvirus infection.

Cat 6 mo increases symptoms: online physician charting and more

The physicians of the Children's Asthma Center and the computer scientists of Information Services at Texas Children's Hospital set out to design a system that is comfortable to use, structured enough to effectively measure outcomes, yet flexible enough to conserve the individuality of the patient. To achieve these goals, we examined how the differential diagnosis process is applied to clinical decision making and implemented it in a clinical workstation. Unique patterns representing the state of the patient's disease are formed by dynamically selecting pertinent sets of observations, assigning attributes to these observations, and describing relationships between observations and/or sets of observations.

A new method to localize brain nuclei for surgery in extrapyramidal disease

A CT localization method to be used with the Leksell stereotactic system was employed to locate the ventral lateral nucleus of the thalamus (VL) and globus pallidus (GP) for treating extrapyramidal disease (EPD). The study comprised 100 normal adults and 70 cases of EPD, and results in both populations were compared. The 70 cases of EPD were studied ventriculography, and 30 normal adults were studied my MRI. Results indicate the accuracy of localization of the primary targets was 94.25% with the CT localization method described herein and 88.9% in the control group. In conclusion, the new CT localization method is a valuable technique to locate brain nuclei and to replace ventriculography with stereotactic surgery in the treatment of EPD patients.

Steady-State Formulation for Stress and Distortion of Welds

A steady state formulation has been developed for thermal stress analysis. It uses features from both the Lagrangian formulation and the Eulerian formulation. The mesh sits on an Eulerian frame but deforms as if in the Lagrangian frame. Therefore, it is suitable for steady state problems with free boundaries. History dependent parameters are integrated along flow lines. A significant gain in computing speed and/or spatial resolution over transient analyses has been achieved together with a noticeable reduction for memory requirements. Numerical results are given for a three-dimensional analysis of edge weld.

Development of a lambda-based complementation assay for the preliminary localization of lacI mutants from the Big Blue mouse: implications for a DNA-sequencing strategy

The Big Blue transgenic mouse carrying the E. coli lacI gene as a mutational target in a lambda-based shuttle vector has been receiving increasing attention in genotoxicity testing because it offers the potential of studying mutation in a mammalian system in vivo. The system not only provides information on mutant frequency, but it also offers the potential of providing information about mutational specificity. Such data is not only important for studies of mutational mechanisms; it offers a critical advantage for determining the mutational response at levels where significant increases in mutant frequency have not been discerned. The repeated sequencing of the entire 1080-bp lacI target, however, remains a formidable task. Here we report on the adaptation of the "negative complementation" assay for the lacI-d phenotype to accommodate the lambda lacI recovered from the Big Blue transgenic animal. This assay permits the localization of mutations to an approximately 330-bp region to facilitate the production of mutational specificity data. The assay is based upon lysogenization of the lambda containing the lacI mutation into a lacI+ host. Of 107 sequenced lacI mutants recovered from Big Blue mice, 74 were identified as NC+ (lacI-d) using this assay. Of these 74, 49 occurred in the region 32-208 bp, which has traditionally been viewed as the NC+ domain. 33 of these mutations were previously identified as producing the NC+ phenotype while another 7 occurred at sites where NC+ mutants have been recovered, but involved a new base substitution. 9 mutants involved new sites. An additional 25 mutants located downstream of the presumed NC+ region were also found to be NC+ as determined by their blue colour on X-gal plates. Of these, 18 occurred in the 209-360-bp region. In parallel, 54 lacI mutants carrying unknown mutations were examined. 37 of these produced blue colonies in this assay. The sequencing of these mutants revealed that 20 (54%) of the 37 mutants were located in the 32-208-bp region. This complementation assay can potentially reduce the amount of DNA sequencing necessary to produce a mutational spectrum by optimising the choice of sequencing primers, and thus provide a significant saving of the material and time required. Furthermore, evidence indicates that the restriction of the mutational target to the NC+ region extends these savings without reducing the usefulness of the mutational specificity data.

240-kDa proteasome inhibitor (CF-2) is identical to delta-aminolevulinic acid dehydratase

The 240-kDa proteasome inhibitor has been reported to be an ATP-stabilized component (CF-2) of the 26 S proteasome complex. We now report that this inhibitory factor is indistinguishable from delta-aminolevulinic acid dehydratase (ALAD), the second enzyme in the pathway of heme synthesis, based upon the following observations: 1) common sequence of the first 14 N-terminal amino acids; 2) identical migration on native and SDS-polyacrylamide gel electrophoresis; 3) identical isoelectric points of pH 7.1; 4) cross-reactivity of specific polyclonal antibodies; 5) similar dehydratase and proteasome inhibitor specific activities in both proteins; and 6) the presence of both activities in recombinant ALAD. The dual role of this protein as CF-2 in the ATP/ubiquitin-dependent pathway and in heme synthesis may be an example of "gene sharing" and explains the unexpected abundance of ALAD noted in earlier studies.

Effects of defocus and primary spherical aberration on images of a straight edge in confocal microscopy

The effects of defocus and primary spherical aberration on the images of a straight edge in a confocal microscope are investigated. When the aberrations are small, the sharpness of the edge image may be enhanced. But the images are degraded if the aberrations become strong in the system. In the latter case, one can improve the quality of the edge images, particularly the sharpness, by slightly reducing the aperture size of the objective and the collection lenses. This result is qualitatively verified by experimental results.

Influence of spherical aberration on axial imaging of confocal reflection microscopy

The influence of spherical aberration on axial imaging of confocal reflection microscopy is investigated. In particular, the effects of lens aperture size and of the first three orders of spherical aberration are inspected. It is shown both theoretically and experimentally that the aberrated axial response can be improved by slightly reducing the lens aperture size. The experimental results concerning the effect of the tube length on the axial response and the aberration compensation are also given.

Selective modulation of the interaction of alpha 7 beta 1 integrin with fibronectin and laminin by L-14 lectin during skeletal muscle differentiation

The alpha 7 beta 1 integrin was originally identified and isolated from differentiating skeletal muscle and shown to be a laminin-binding protein (Song et al. (1992) J. Cell Biol. 117, 643–657). Expression of the alpha 7 gene and protein are developmentally regulated during skeletal muscle differentiation and have been used to identify cells at distinct stages of the myogenic lineage (George-Weinstein et al. (1993) Dev. Biol. 156, 209–229). The lactoside-binding protein L-14 exists as a dimer and has been localized on a variety of cells, in association with extracellular matrix. During myogenesis in vitro, L-14 is synthesized within replicating myoblasts but it is not secreted until these cells commence terminal differentiation and fusion into multinucleate fibers (Cooper and Barondes, J. Cell Biol. (1990) 110, 1681–1691). Addition of purified L-14 to myogenic cells plated on laminin inhibits myoblast spreading and fusion, suggesting that the L-14 lectin regulates muscle cell interactions with the extracellular matrix that are germane to myogenic development (Cooper et al. (1991) J. Cell Biol. 115, 1437–1448). We demonstrate here, using affinity chromatography and immunoblots, that alpha 7 beta 1 also binds to fibronectin and to the L-14 lectin. L-14 binds to both laminin and to the alpha 7 beta 1 integrin, and it can effectively inhibit the association of laminin and this integrin. Modulation of alpha 7 beta 1 interaction with its ligands by L-14 is selective: L-14 does not bind to fibronectin, nor does it interfere with the binding of fibronectin to alpha 7 beta 1.(ABSTRACT TRUNCATED AT 250 WORDS)

The use of mixture models to detect effects of major genes on quantitative characters in a plant breeding experiment

An analysis based on Elston's model of mixed major locus and polygenic inheritance is extended to include populations of progeny testing such as F3, B1s and B2s families derived from F2 and backcrosses in a cross between two inbred lines. Genetic hypotheses that can be validly tested by the likelihood ratio method in the analysis of a breeding experiment include homogeneity of variances due to environment and/or polygenes with transformable scale effect by Box-Cox power function, random and independent segregation of major genes, invariance of the effects of major genes with population types and additive and dominant models for polygenes. Testing hypotheses in the order suggested here can lead to a gradual simplification of the models and increases the feasibility of the subsequent analysis, but caution must be paid to the possible bias in parameter estimation and hypotheses tests. The procedure is applied to a set of data on plant height of rice with the effects of dwarf genes in crosses among three varieties. Two recessive dwarf genes are shown to be nonallelic and unlinked. One dwarf gene is shown to reduce plant height about 36-56 cm, and another 52-61 cm. The effect of polygenes, estimated as the standard deviation among possible inbred lines derived from these crosses, is about 11.7 cm. Interactions between the dwarf genes and the polygenic background are found, especially for one of the two genes. Both the polygenic effects and the interactions are much smaller than the effects of the major dwarf genes.

Long range propagation of conformational changes in integrin alpha IIb beta 3

Integrin adhesion receptors participate in two-way transfer of information across the plasma membrane. For example, cytoplasmic events, such as activation of protein kinase C, cause an increase in the fibrinogen (Fg) binding affinity of the extracellular domain of integrin alpha IIb beta 3 ("inside-out signaling"). Conversely, ligand binding to alpha IIb beta 3 results in the generation of intracellular signals. We used anti-LIBS2, an anti-beta 3 monoclonal antibody, to understand potential mechanisms of this bidirectional signaling. Anti-LIBS2 bound to alpha IIb beta 3 with low affinity (Kd = 7.4 microM), and mimicked inside-out signaling by promoting Fg binding. The affinity of anti-LIBS2 binding was increased 20-fold (Kd = 326 nM) by addition of an Fg-mimetic synthetic peptide, RGDS. Thus, anti-LIBS2 and ligands (Fg and Fg-mimetic peptides) bind cooperatively to integrin alpha IIb beta 3, indicating a functional linkage between the ligand-binding site and the antibody-binding site. The anti-LIBS2-binding site was mapped by its binding to proteolytic and recombinant fragments of the beta 3 subunit. The epitope was located within an 89-residue region immediately adjacent to the transmembrane domain and 400 residues carboxyl-terminal to the known ligand-binding site(s). Electron microscope images of rotary shadowed ternary complexes of Fg, anti-LIBS2, and alpha IIb beta 3 revealed that the ligand-binding site and anti-LIBS2 epitope are separated by about 16 nm. This indicates that propagated long distance conformational changes can occur in alpha IIb beta 3. Such changes are likely to be involved in the bidirectional signaling function of this integral membrane protein.

Modulation of herpes simplex virus type 1 replication by human salivary secretions

Saliva functions to protect the oral cavity from pathogenic invasion by modulating the ability of microbes to colonize the oral surfaces or limiting their growth and/or viability. Although the role of salivary secretions in the modulation of the oral bacteria flora has received considerable attention, little is known concerning its role in viral pathogenesis. Accordingly, the purpose of this study was to assess the effect of salivary secretions on herpes simplex virus type 1 (HSV-1) replication. Initially, HSV-1 plaque and titer reduction assays were performed to determine the ability of human submandibular/sublingual (HSMSL) and parotid (HPS) salivas to inhibit the early stages of HSV-1 infection (adsorption and penetration). Our results suggested that both HSMSL and HPS possess cell-protective and virus neutralization activities, with HSMSL being more active than HPS. Additional experiments were performed to determine the effect of saliva on the yield of virus progeny. Again, HSMSL caused a greater reduction of HSV-1 replication than did HPS. A similar effect could not be obtained using vaccinia, suggesting that this inhibitory activity of human saliva is selective. Collectively, these results suggest that human salivary secretions can modulate the replication of HSV-1 in vitro.