[Specific monoclonal antibodies to F41 adhesin of enterotoxigenic Escherichia coli and their potential uses as diagnostic and therapeutic reagents]

A set of hybridoma cell lines, namely, L10, B10, C32, B1, E7, E40 and B49, secreting monoclonal antibodies (MABs) specific to F41 adhesin antigens of ETEC was obtained by somatic hybridization. These MABs manifested strongly specific binding reactivities in DA, ELISA and IFA to all tested F41+ ETEC strains. All these MABs recognized the same or closely related epitopes on the adhesin, as indicated in antigen-competition ELISA with HRP-labeled MABs. The distribution patterns of these epitopes which appeared repeatedly on each pilus were visualized by MAB-immunogold technique and immunoelectron microscopy. The adhesion of ETEC bearing F41 adhesin to the epithelial cells of small intestine from new borne calves and piglets was inhibited in vitro by F41-specific MABs. A dot-immunobinding assay based on F41-specific MABs was developed for determining F41 antigens in fecal samples with HRP-labeled MABs. The assay was highly sensitive and specific, and could be used in rapid detection and screening of F41 adhesin antigens in field samples.

Pharmacokinetics and autoradiography of [3H] or [14C]stepholidine

After iv [3H]stepholidine (SPD) 12 MBq/kg, the concentration-time curve in rats was found to be a two-compartment open model. The distribution phase T1/2 alpha = 3.6 min, the elimination phase T1/2 beta = 168 min. The absorbed radioactivities of [3H] SPD in 15-30 min were 80-87%. The amounts of [3H]SPD bound to plasma protein, liver and kidney homogenates were estimated to be 37, 31, and 30%, respectively. During 3 d after ip [3H]SPD 50 MBq/kg, 56% of the radioactivity was excreted in urine and 5% in feces, thus, it suggested that [3H]SPD was mainly excreted by kidneys. After iv a single dose of [14C]SPD in mice, the whole-body autoradiography showed that [14C]SPD was rapidly distributed among various tissues. High radioactivities were found in kidneys, liver, brain, salivary glands, Harder's glands, heart blood and muscle at 2 min and intensively localized in kidneys and stomach mucosa at 30 min. The radioactivities in these tissues disappeared 4 and 8 h later, while that in intestine could not be detected 24 h later.

Effect of a cell differentiation inducer, ganglioside GM3, on the neutral glycosphingolipid composition and cell membrane fluidity of a human promyelocytic leukemia cell line HL-60

In this paper the authors confirmed the finding reported by Nojiri et al that exogenous ganglioside GM3 could induce HL-60 cells to differentiate along the monocytic-macrophage route with significant inhibition of proliferation. It was found that after differentiation the neutral GSL content of CDH and CMH increased, while that of CXH, a polyhexosyl ceramide with a TLC mobility slower than CQH, decreased significantly. The membrane fluidity of HL-60 cells decreased after GM3 treatment.

Molecular Characterization of the Brittle-2 Gene Effect on Maize Endosperm ADPglucose Pyrophosphorylase Subunits

Activity of the enzyme ADPglucose pyrophosphorylase is known to be reduced in maize (Zea mays L.) endosperm mutants at two independent loci, Shrunken-2 (Sh(2)) and Brittle-2 (Bt(2)). Spinach leaf ADPglucose pyrophosphorylase has previously been shown to comprise two subunits of 51 and 54 kilodaltons. Anti-bodies raised to each of the two subunits of spinach leaf ADPglucose pyrophosphorylase were found to cross-react to different bands on Western blots prepared from polyacrylamide gel electrophoresis separated wild-type maize endosperm proteins. The anti-spinach leaf 51 kilodalton subunit antibody cross-reacted with a 55 kilodalton maize endosperm protein and the anti-spinach leaf 54 kilodalton subunit antibody cross-reacted with a 60 kilodalton maize endosperm protein. These immunological reactions were observed in maize endosperm extracts and with a highly purified preparation of maize endosperm ADPglucose pyrophosphorylase. Mutant bt(2) endosperm lacked the 55 kilodalton subunit while mutant sh(2) endosperm lacked the 60 kilodalton subunit on Western blots. These results suggest that the maize endosperm ADPglucose pyrophosphorylase is made up of two immunologically dissimilar subunits and that the bt(2) and sh(2) mutations cause reduction in ADPglucose pyrophosphorylase activity through the lack of one of these two subunits. An ADPglucose pyrophosphorylase cDNA clone antigenically selected from a rice seed cDNA expression library was found to hybridize strongly with a cDNA corresponding to a maize endosperm transcript which is absent in a W64A bt(2) mutant. Thus, the bt(2) mutant causes the absence not only of the small subunit but of the corresponding transcript. Bt(2) is implicated as the structural gene for the small (54 kilodalton) subunit of maize endosperm ADPglucose pyrophosphorylase.

[Relation of the changes in hemorheologic indices and the site and size of cerebral infarction]

According to the CT findings, 83 cases of cerebral infarction were divided into two groups. One group consisted of cases with occlusion of the cerebral arterial main trunks and the other of those with occlusion of the penetrating arteries. The HCT and the whole blood viscosity were higher in the former group, whereas the rate of platelet aggregation was higher in the latter group. These results suggested that the physiopathology involved in the formation of the large cerebral infarction in the cerebral cortex and subcortex was different from that of the small infarction in the deep cerebral structures. Besides, it was found that the blood viscosity has positive relationship with the size of the cerebral infarction in the former group. It was presumed that the HCT and the blood viscosity should be reduced immediately for treating the larger cerebral infarction, but to lower the rate of platelet aggregation for treating the small infarction in the deep cerebral structures would be of benefit.

Effects of strophanthidin on the slow inward current in guinea-pig isolated ventricular myocytes

1. The effect of strophanthidin on the slow inward current (Isi) and on contractile force were studied in guinea-pig isolated ventricular myocytes and intact papillary muscles, respectively. In myocytes, both low (10 nmol/L) and high (1-10 mumols/L) concentrations had small or no effects in either direction on Isi whereas norepinephrine (10-100 nmol/L) increased it. To determine whether the same results are obtained after decreasing or increasing intracellular calcium or sodium, the same concentrations of strophanthidin were tested in different procedures that are known to (i) increase [Ca]i and decrease [Na]i (high [Ca]o, 3.6-5.4 mmol/L; low [Na]o, 112 mmol/L; (ii) decrease [Ca]i and increase [Na]i (low [Ca]o, 0.45-1 mmol/L; Sr, 1 mmol/L; (iii) decrease [Ca]i and [Na]i (Cd, 0.1-0.2 mmol/L); and (iv) increase [Ca]i and [Na]i (veratridine, 0.2 mumol/L). High [Ca]o and veratridine increased whereas low [Ca]o and Cd decreased Isi. In contrast, during these various procedures, strophanthidin had small and inconsistent effects at a low or high concentration. In intact papillary muscles, low strophanthidin decreased whereas high strophanthidin increased contractile force. It is concluded that strophanthidin has little direct or indirect effect on Isi and that the decrease in force by low and increase in force by high concentrations in intact muscle are probably related to demonstrated decrease and increase, respectively, in intracellular sodium activity.

[The effect of intrapartum and neonatal asphyxia on the cognitive and behavioral development of children]

The present study includes 4 groups of subjects: 30 children with a history of intrapartum asphyxia, 30 children with a history of mild neonatal asphyxia, 15 children with a history of severe but transitory neonatal asphyxia, and 30 children who had normal deliveries. Psychological and neuropsychological assessments were done at 6 years of age. There are no significant difference among 4 groups in IQ, social maturity age, most neuropsychological functions and incidence of attention deficit disorder with hyperactivity. 4 test scores in Halstead-Reitan Battery infer to visual-motor functioning showed backwardness in asphyxiated groups. Behavior problems are more frequently seen in the asphyxiated groups than in the control group.

Nonlinear-optical response in polythiophene films using four-wave mixing techniques

We report measurement of X(3) in polythiophene and a homologous series of polycondensed thiophene-based polymers above and below the absorption edge using the folded-boxcar four-wave mixing technique. Above gap the nonlinear coefficient X(3) was found to be one of the largest and fastest in a polymer.

Quinacrine decreases the slow inward current and force in guinea pig ventricular tissue

In guinea pig isolated ventricular myocytes, quinacrine (40 microM) decreases the action potential amplitude and duration, and markedly decreases the slow inward current (Isi). A lower quinacrine concentration (20 microM) has similar but smaller effects. In guinea pig papillary muscles, quinacrine decreases contractile force reversibly. Thus, in myocardial fibers the decrease in Isi by quinacrine appears to predominate over the inhibition of Na-Ca exchange found in membrane vesicles.

Template supercoiling during ATP-dependent DNA helix tracking: studies with simian virus 40 large tumor antigen

Incubation of topologically relaxed plasmid DNA with simian virus 40 (SV40) large tumor antigen (T antigen), ATP, and eubacterial DNA topoisomerase I resulted in the formation of highly positively supercoiled DNA. Eukaryotic DNA topoisomerase I could not substitute for eubacterial DNA topoisomerase 1 in this reaction. Furthermore, the addition of eukaryotic topoisomerase I to a preincubated reaction mixture containing both T antigen and eubacterial topoisomerase I caused rapid relaxation of the positively supercoiled DNA. These results suggest that SV40 T antigen can introduce topoisomerase-relaxable supercoils into DNA in a reaction coupled to ATP hydrolysis. We interpret the observed T antigen supercoiling reaction in terms of a recently proposed twin-supercoiled-domain model that describes the mechanics of DNA helix-tracking processes. According to this model positive and negative supercoils are generated ahead of and behind the moving SV40 T antigen, respectively. The preferential relaxation of negative supercoils by eubacterial DNA topoisomerase I explains the accumulation of positive supercoils in the DNA template. The supercoiling assay using DNA conformation-specific eubacterial DNA topoisomerase I may be of general use for the detection of ATP-dependent DNA helix-tracking proteins.

Identification of a developmentally regulated gene for a 140-kDa secretory protein in salivary glands of Chironomus tentans larvae

Secretory proteins are synthesized in salivary glands of the insect, Chironomus tentans, and assemble in vivo into silk-like threads which aquatic larvae use to construct tubes for filter feeding and pupation. Thus far, all known secretory protein genes contain repetitious protein-coding sequences and are located in cytological structures known as Balbiani rings, giant puffs found on polytene secretory cell chromosomes. In this paper we describe the identification of another secretory protein gene which is comprised of repeated sequences; however, this gene is not located in a Balbiani ring. Two partial cDNA clones from a 3.6-kilobase pair poly(A)+ RNA were sequenced and found to contain two open reading frames for protein synthesis. Antibodies were raised against synthetic oligopeptides whose sequences were derived from these two open reading frames. An immunoaffinity-purified antibody for one of these peptides bound specifically to a 140-kDa secretory protein (sp140). The cDNA sequences contain tandem repeats of 42 base pairs which encode a repeat of 14 amino acids with a composition and oligopeptide sequence similar to other secretory proteins. The C. tentans genome contains about 70 copies of this 42-base pair repeat organized as a contiguous block of 3 kilobase pairs or less. The sp140 gene was mapped by in situ hybridization to polytene chromosome band I-17-B. Developmental studies of protein accumulation, steady-state levels of mRNA, and relative transcription rate suggested that the sp140 gene is developmentally regulated so that maximal expression is achieved during the prepupal stages of the fourth larval instar. Based upon these results we proposed that sp140 gene belongs to a prepupal class of secretory protein genes. While the sp140 gene shares structural and expression characteristics with other secretory protein genes, its unique chromosomal location shows that this multigene family is not restricted to Balbiani rings.

Self-phase modulation in multimode optical fibers produced by moderately high-powered picosecond pulses

The spectral distributions of 8-psec ultrashort laser pulses propagating through multimode glass fibers were measured and compared with those of single-mode fibers at comparable intensities. In multimode optical fibers the spectral broadening arising from self-phase modulation was found to be asymmetric to the Stokes side owing to modal dispersion.

Discussion of the optics of a new 3-D imaging system

The geometric optics of a new 3-D imaging system, which has several innovative features, is discussed. The principles governing the primary design of the system are considered in some detail, and the calculation method employed in achieving the basic design parameters is presented. The aberration of the system is then investigated in detail using primary aberration theory, and the limitations imposed on a light beam passing through the arrangement is discussed quantitatively.

Three-dimensional imaging systems: a new development

An optical system which produces 3-D images exhibiting continuous parallax with no flipping or cardboarding is described. Both integral and lenticular images can be recorded on photographic film without recourse to a specialized environment. Standard photographic processing and enlarging techniques are used to obtain hard copy. Measurements on commercially available retrodirective screens and a new retroscreen arrangement show that the new screen developed gives significant advantages. A retrodirective and a transmission version of the system have been constructed.

Identification of a downstream sequence and binding protein that regulate adenovirus major late promoter transcription in vitro

Gel electrophoresis mobility shift and DNase I footprint assays detect a cellular nuclear protein in extracts made from uninfected human cells which binds to a downstream promoter sequence (DPS) in the human adenovirus 2 major late promoter. By DNase I footprint and mutation analyses, we have determined that this new regulatory element extends from positions +146 to +165 (relative to the cap site at position +1). We show by UV cross-linking that a 40-kDa polypeptide specifically binds to this region. Mutations within the DPS which decrease protein binding by 80-90% also cause a 2.5-3-fold decrease in in vitro major late promoter transcription efficiency. Alteration of the template in the 5'-flanking region of the DPS does not affect nuclear protein binding or transcription efficiency. Interestingly, a T----G transversion at position +160 which increases protein binding also impairs promoter activity.