Remote eye tracking assesses age dependence processing of coherent motion in typically-developing children.

The aim of this study was to quantify processing of different types of coherent motion in terms of ocular motor response times in a group of normally-developing children (age 0-12+ years old) using remote eye tracking. Motion coherence was applied in three different types of Random Dot Kinematograms (RDKs): vertical (RDK1) and diagonal (RDK2) motion and expansion (RDK3). Orienting eye movements were quantified using the Reaction Time to the first Fixation (RTF). The children were divided into two groups: the "youngest group" between 0-3+ years and the "oldest group" between 4-12+ years old. The results showed that RTF was significantly prolonged in the "youngest group" compared to the "oldest group" for each RDK. In the "oldest group", RTF was significantly affected by the type of RDK shown. The presented results suggest that, based on ocular motor responses, age-dependence of processing different types of coherent motion may be revealed.

Osmotic stress and cryoinjury of koala sperm: an integrative study of the plasma membrane, chromatin stability and mitochondrial function.

This study investigated whether cryopreservation-induced injury to koala spermatozoa could be explained using an experimental model that mimics the structural and physiological effects of osmotic flux. DNA labelling after in situ nick translation of thawed cryopreserved spermatozoa revealed a positive correlation (r=0.573; P<0.001; n=50) between the area of relaxed chromatin in the nucleus and the degree of nucleotide labelling. While the chromatin of some spermatozoa increased more than eight times its normal size, not all sperm nuclei with relaxed chromatin showed evidence of nucleotide incorporation. Preferential staining associated with sperm DNA fragmentation (SDF) was typically located in the peri-acrosomal and peripheral regions of the sperm head and at the base of the spermatozoa where it appear to be 'hot spots' of DNA damage following cryopreservation. Results of the comparative effects of anisotonic media and cryopreservation on the integrity of koala spermatozoa revealed that injury induced by exposure to osmotic flux, essentially imitated the results found following cryopreservation. Plasma membrane integrity, chromatin relaxation and SDF appeared particularly susceptible to extreme hypotonic environments. Mitochondrial membrane potential (MMP), while susceptible to extreme hypo- and hypertonic environments, showed an ability to rebound from hypertonic stress when returned to isotonic conditions. Koala spermatozoa exposed to 64 mOsm/kg media showed an equivalent, or more severe, degree of structural and physiological injury to that of frozen-thawed spermatozoa, supporting the hypothesis that cryoinjury is principally associated with a hypo-osmotic effect. A direct comparison of SDF of thawed cryopreserved spermatozoa and those exposed to a 64 mOsm/kg excursion showed a significant correlation (r=0.878; P<0.05; n=5); however, no correlation was found when the percentage of sperm with relaxed chromatin was compared. While a cryo-induced osmotic injury model appears to explain post-thaw changes in koala SDF, the mechanisms resulting in relaxed chromatin require further study. A lack of correlation between the percentage of sperm with relaxed chromatin and SDF suggests that the timing of these pathologies are asynchronous. We propose an integrative model of cryo-induced osmotic injury that involves a combination of structural damage (rupture of membrane) and oxidative stress that first leads to the reduction of MMP and the relaxation of chromatin, which is then ultimately followed by an increase in DNA fragmentation.

Non-small cell lung cancer presenting with neoplastic fever at diagnosis and relapse.

Fever occurs frequently in cancer patients, and neoplastic fever is a well-described paraneoplastic phenomenon in patients with lymphoma, acute leukemias, and renal cell carcinoma. It is also more commonly encountered in metastatic disease. Treatment options include disease-specific therapy, non-steroidal anti-inflammatory drugs (NSAIDs), and steroids. Lung cancer is one of the most common cancers, yet fever as a manifestation of this malignancy has not been emphasized. In this report, we describe an unusual case of non-metastatic non-small cell lung cancer (NSCLC) presenting with neoplastic fever at both diagnosis and relapse, responding on each occasion to disease-specific treatment, and provide a review of the management of neoplastic fever.

Patient and disease characteristics, and outcome of treatment defaulters from the Singapore TB control unit--a one-year retrospective survey.

SETTING: The Singapore Tuberculosis Control Unit. OBJECTIVES: 1) To identify any demographic, social, disease or treatment-related characteristics which may be predictive of patients defaulting from treatment; 2) to assess the effectiveness of home visits as a means of defaulter recall; 3) to ascertain outcome in these patients. DESIGN: A retrospective, case-controlled study of TB treatment defaulters, defined as patients who missed their scheduled appointments and required a home visit to recall for treatment. Controls were randomly selected, non-defaulting patients who started treatment on the same dates as the defaulters. RESULTS: Forty-four patients required home visits in 1996. Compared to controls, defaulters were more likely to be non-Chinese, and to live on their own or with friends. There was no significant association of defaulting with age, sex, marital or employment status, disease characteristics, or treatment-related factors. Seventy per cent defaulted during the continuation phase of treatment. Home visits did not result in contact with the patient (or any other person) 41% of the time. Although 48% of the defaulters remained lost to follow-up at the time of the survey, all but one of the sputum-positive patients had bacteriologically converted by the time of default. CONCLUSION: Non-Chinese ethnicity and lack of family support were found to be factors strongly predictive of default. Age, sex, marital and employment status, treatment-related factors and disease characteristics were not significant in distinguishing those at risk for defaulting.

Degradation of rRNA in Salmonella strains: a novel mechanism to regulate the concentrations of rRNA and ribosomes.

We have previously shown that the 23S rRNA of Salmonella strains is highly fragmented by specific enzyme cleavages. In this article, we report that 23S rRNA of Salmonella strains is rapidly degraded as the cells enter the stationary phase. More than 90% of the 23S rRNA is degraded when the cells reach the stationary phase. The rate of degradation of 23S rRNA correlated with its degree of fragmentation. This degradation is probably mediated by newly synthesized protein factor(s), since treatment with chloramphenicol or rifampin inhibits the rRNA degradation. We propose that degradation of 23S rRNA is a novel mechanism in the regulation of the bacterial 23S rRNA and ribosome concentration and that this additional regulatory mechanism provides some selective advantage to cells.

Comparison of herpesvirus isolates from falcons, pigeons and psittacines by restriction endonuclease analysis.

Field isolates of herpesviruses recovered from falcon, pigeon, and psittacine birds were compared by restriction endonuclease (RE) analysis using four separate enzymes. Pigeon and falcon herpesviruses had strikingly similar DNA cleavage patterns, while DNA cleavage pattern of virus isolates from a double-yellow headed Amazon and an African grey parrot had different genomic patterns to both the pigeon and falcon herpesviruses. These findings support the field observations that pigeon herpesvirus causes a fatal herpesviral infection in the livers of pigeon-eating falcons.

Diversity of cleavage patterns of Salmonella 23S rRNA.

The recent discovery of the phenomenon that some prokaryotes fragment their 23S rRNA during post-transcriptional processing of precursor rRNA has been shown to be particularly prevalent among strains and species of Salmonella. Some strains of Salmonella cleaved 23S rRNA at multiple sites producing several fragments. The cleavage patterns of 23S rRNA differed among Salmonella strains and sometimes among the rRNA operons in the same strain. Fragmentation of 23S rRNA was not observed in strains of the closely related species Escherichia coli. Fragmentation of 23S rRNA occurred in Brucella and Agrobacterium but the cleavage pattern was not as diverse as that demonstrated in Salmonella. Introduction of cleavage sites into precursor 23S rRNA of Salmonella is probably a recent evolutionary event.

Complete nucleotide and deduced amino acid sequence of genome segment 5 encoding the outer capsid protein, VP5, of a U.S. isolate of bluetongue virus serotype 11.

The complete nucleotide sequence of the RNA genome segment coding for the outer capsid protein, VP5, of the United States prototypic strain of bluetongue virus (BTV) serotype 11 was determined from two overlapping cDNA clones. The genome segment was found to be 1638 nucleotides in length with a single open reading frame coding for a 526 amino acid protein of MW 59,278 and having a net charge of -4.0 at neutral pH. Comparisons of the predicted amino acid sequence of VP5 of BTV 11 with those of the United States serotypes 2, 10, and 13 and two isolates of BTV 1 from Australia and South Africa confirmed earlier reports that VP5 is a conserved protein with no clear regions of variability. A computer generated consensus sequence suggested VP5 of BTV 2 to be representative of the average VP5 sequences reported thus far.

Fluoride uptake in bovine enamel and dentin from a fluoride-releasing composite resin.

To determine the fluoride uptake in enamel and dentin, a fluoridating composite resin was fixed at a 100-microns distance from bovine enamel and dentin for 2 weeks. The results revealed a substantial increase in the level of fluoride in both enamel and dentin. This model investigation showed that the fluoride released by the composite resin was effectively taken up by the surrounding tissues. The fluoride released from the composite resin and the subsequent uptake by the tissues would be expected to protect against secondary caries.

Unique ribosome structure of Leptospira interrogans is composed of four rRNA components.

All known ribosomes of procaryotic organisms are made up of three rRNA components that are 23, 16, and 5S in size. We now report that in some Leptospira interrogans strains, the classical 23S rRNA is further processed to generate 14 and 17S rRNAs. This processing step was previously known to occur only in some eucaryotes and in a small group of procaryotes. The implications of this finding are discussed.

Nucleotide sequence of a 3.5 kilobase fragment of malignant catarrhal fever virus strain WC11.

A 3.5 kilobase DNA fragment of the malignant catarrhal fever virus (MCFV), strain WC11, was mapped with a number of restriction enzymes, subcloned and sequenced. The fragment was subcloned into plasmid vector, pUC19, for direct sequencing. A complete open reading frame of 2,058 base pairs and a partial open reading frame of 630 base pairs were identified. The sequence of 3,389 nucleotides was compared to other herpesviruses. A 310 base pairs sequence in gene A was 57% homologous to a sequence in reading frame BXLF1 of Epstein-Barr virus strain B95-8.

A diagnostic method to detect alcelaphine herpesvirus-1 of malignant catarrhal fever using the polymerase chain reaction.

A sensitive diagnostic method specific for alcelaphine herpesvirus-1, causative agent of malignant catarrhal fever, has been developed. Based on the nucleotide sequence of the alcelaphine herpesvirus-1 genomic DNA, a pair of 30 nucleotide primers was selected and synthesized for detecting the virus genome using the polymerase chain reaction (PCR). The virus genome was detected in crude cell lysate using the amplification reaction.

Comparison of genomes of malignant catarrhal fever-associated herpesviruses by restriction endonuclease analysis.

The restriction endonuclease DNA cleavage patterns of eight isolates of malignant catarrhal fever-associated herpesviruses were examined using the restriction endonucleases HindIII and EcoRI. The eight viruses could be assigned to two distinct groups. Virus isolates from a blue wildebeest, a sika deer and an ibex had restriction endonuclease DNA cleavage patterns that were in general similar to each other. The restriction pattern of these three viruses was distinct from the other five. Of these five, four were isolated from a greater kudu, a white tailed wildebeest, a white bearded wildebeest, and a cape hartebeest. The fifth isolate C500, was isolated from a domestic cow with malignant catarrhal fever. These five viruses had similar DNA cleavage patterns.

Cloning and characterization of a genomic probe for malignant catarrhal fever virus.

A genomic probe specific for malignant catarrhal fever (MCF) virus was cloned by using purified viral DNA from MCF-virus strain WCll. Restriction endonuclease analysis of the purified viral DNA was used to identify the cloned viral genomic fragment. Dot blot hybridization by use of the genomic probe (pRP-5) indicated that the probe hybridized specifically with WCll-MCF virus, as well as with one other isolate of MCF-associated herpesvirus. Hybridization also was observed to a non-MCF virus strain of bovine herpesvirus.

Enhancement of allergic lung sensitization in mice by ozone inhalation.

Inhaled ozone was found to exert an enhancing effect for allergic lung sensitization when mice contracted an aerosolized allergen. The animals were exposed to ozone concentrations of 0.24, 0.16, 0.13, and 0.10 ppm. After 4 days of continuous ozone exposure, the mice had allergen contact from an aerosolized solution of ovalbumin. The animals were then maintained in ambient air for several days before the cycle of ozone and aerosolized allergen was repeated over four allergen contact cycles. Mice were rested in ambient air for a week after the last allergen contact, and they were then tested for allergic sensitization by the intravenous injection of 2 mg of ovalbumin to induce anaphylactic shock in allergic individuals. The control groups of mice were maintained in ambient air throughout the experiment, but they experienced identical allergen contact with the ozone-exposed mice. The phenomenon of allergic enhancement from ozone inhalation was detected at 0.24, 0.16, and 0.13 ppm of ozone. The enhancing effect disappeared at 0.10 ppm of ozone. The study indicated a potential for increasing the number of allergically sensitized individuals when various allergens are inhaled during periods of high ozone exposure with the consequent adverse changes on respiratory membranes. The significance to human health of the allergic enhancement phenomenon by ozone needs investigation.

Enzyme-linked immunosorbent assay for the detection of antibodies to bovine virus diarrhea virus in sera from border disease virus-infected sheep.

An enzyme-linked immunosorbent assay (ELISA) was established for the rapid detection of specific antibodies against the causative agent of border disease in ovine sera. Polyethylene-glycol concentrated, equilibrium density gradient purified bovine virus diarrhea virus was used as test antigen. The optimal amount of antigen was 0.5 microgram/well, and the optimal concentration of conjugate was at 1/4,000 dilution. A total of 20 ovine serum samples, which had been collected from animals with or without border disease, were compared by ELISA and serum neutralization test for the detection of border disease-specific antibodies. ELISA was shown to be equally specific but less time-consuming and easier to perform than serum neutralization test. A positive correlation (r = 0.60) between the two tests was found.

Neutralizing monoclonal antibodies directed to infectious bovine rhinotracheitis virus.

Infectious bovine rhinotracheitis virus (IBRV) has been shown in this report to have thirty-three polypeptides. Ten of the eleven polypeptides which can be labeled with (3H)-glucosamine are located on the surface of the virus since they can be surface labeled with sodium boro(3H)hydride. In order to define the immunologically important viral proteins, monoclonal antibodies were prepared against the virus and selected for their ability to neutralize infectivity. Four such hybridoma lines were obtained for characterization of the antigens that elicit neutralizing antibodies. The viral polypeptides were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and the specificity of each monoclonal antibody was determined by "Western" blot analysis and/or by immunoprecipitation of (35S)-methionine and (3H)-glucosamine labeled infected cell lysates by the monoclonal antibodies. One monoclonal antibody reacted with two glycoproteins, gp135 and gp78a, on the "Western" blot but immunoprecipitated three glycoproteins, gp135, gp78a, and gp54 from labeled infected cell lysates. The other three monoclonal antibodies immunoprecipitated a single glycoprotein, gp78b, from (3H)-glucosamine labeled infected cell lysates but not from (35S)-methionine labeled infected cell lysates.

Duration of maternally derived antibodies against equine influenza in newborn foals.

Serum antibody concentrations against influenza A-equi-1 virus and A-equi-2 virus were measured in a group of 18 foals from birth to 4 months of age. More than 50% of the foals were seronegative to A-equi-1 virus infection by 4 weeks of age, with titers of less than or equal to 1:16. For A-equi-2 virus, more than 50% of the foals were seronegative by 2 weeks of age, with titers of less than or equal to 1:8. Passively derived antibodies against influenza A-equi-1 virus and A-equi-2 virus in foals obtained from recently vaccinated mares and from mares not vaccinated within 6 months before foaling were low in titer. The duration of passively derived antibodies was also short-lived.

Enzyme-linked immunosorbent assay for the detection of antibodies to bovine viral diarrhea virus in bovine sera.

A specific and sensitive enzyme-linked immunosorbent assay (ELISA) was established for the detection of antibodies to bovine viral diarrhea virus (BVDV) in bovine sera. Polyethylene-glycol concentrated, equilibrium density gradient purified BVDV was used as test antigen at an optimal amount of 1 microgram/well, whereas the optimal concentration of conjugate was at 1/2000 dilution. The standardized test encountered no non-specific reaction with test sera at a starting dilution of 1/10. A total of 50 bovine serum samples was assayed for the presence of antibodies against BVDV by ELISA and serum neutralization test (SNT). A positive correlation between the 2 tests was found. However, ELISA could be as much as 500-fold more sensitive than SNT in detecting low levels of BVDV antibodies.