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PubMed1995

Health hazards among working children in Texas.

This report represents the first attempt to assemble existing data from a variety of sources regarding children less than 18 years of age in the work force in Texas. These data include the frequency of detected violations of child labor laws, reports of injuries to the Texas Workers' Compensation Commission, and work-related deaths as ascertained from death certificates. More than 1,000 minors were detected as being illegally employed in Texas each year since 1986 and nearly 1,100 work-related injuries in children 18 years of age and younger were reported to the Texas Workers' Compensation Commission in 1991. A review of Texas death certificates from 1980 to 1990 revealed 125 work-related fatalities among children. The leading cause of death was motor vehicle injuries, followed by injuries from machinery (usually agricultural machinery). The magnitude and severity of occupational illnesses in working children are unknown. Because of physiologic differences in size, metabolism, and absorption, children may be especially susceptible to work-related injury and illness. Health and safety data on working children in Texas, as in most other places, are fragmented and incomplete. These data are needed to identify children at high risk of injuries and illnesses, to target prevention programs, and to identify areas for additional legislation. More rigorous enforcement of current legislation is also needed.

Accidents, Occupational↗
PubMed1996

Environmental public health surveillance.

A holistic and collaborative approach needs to be taken in the development of environmental public health surveillance systems. Exposure and hazard surveillance integrated with outcome-based surveillance will blend fragmented strands of data into streams of information. Adequate resources and strong leadership are essential to the creation of such surveillance systems.

Child↗
PubMed2001

DNA-DNA hybridization study of Bradyrhizobium strains.

DNA-DNA hybridizations were performed between Bradyrhizobium strains, isolated mainly from Faidherbia albida and Aeschynomene species, as well as Bradyrhizobium reference strains. Results indicated that the genus Bradyrhizobium consists of at least 11 genospecies, I to XI. The genospecies formed four subgeneric groups that were more closely related to each other (>40% DNA hybridization) than to other genospecies (<40% DNA hybridization): (i) genospecies I (Bradyrhizobium japonicum), III (Bradyrhizobium liaoningense), IV and V; (ii) genospecies VI and VIII; (iii) genospecies VII and IX; and (iv) genospecies II (Bradyrhizobium elkanii), X and XI. Photosynthetic Aeschynomene isolates were found to belong to at least two distinct genospecies in one subgeneric group. DNA-DNA hybridization data are compared with data from amplified fragment length polymorphism analysis and 165-23S rDNA spacer sequence analysis.

Bradyrhizobium↗
PubMed1995

Differentiation of Neisseria gonorrhoeae IB-3 and IB-7 serovars by direct sequencing of protein IB gene and pulsed-field gel electrophoresis.

Serotyping of Neisseria gonorrhoeae based on the differential recognition by a panel of six monoclonal antibodies (MAbs) against Protein IB (PIB) is a valuable tool for studying the epidemiology of gonorrhoea. However, the predominance of certain serovars in specific geographic regions necessitates the development of new MAbs or new genotyping approaches. Nucleotide and amino-acid sequence analysis of PIB from strains within the IB-3 and IB-7 serovars revealed strain differences within the same serovar. Based on the generation of PIB nucleotide and deduced amino-acid sequences that centred on amino-acid residues 196 and 237, eight serovar IB-3 strains and nine serovar IB-7 strains were separately subdivided into five groups. Intra-serovar differences were also established by pulsed-field gel electrophoresis (PFGE) of macro-restriction fragments generated by SpeI- and NheI-cleavage of genomic DNA. There was good correlation between the results based on PIB gene PCR-sequencing and those based on PFGE analysis of macro-restriction fragment patterns. These data demonstrate the high precision of PFGE analysis and indicate that this approach can be used as a rapid epidemiological subtyping system for major serovars of N. gonorrhoeae.

Amino Acid Sequence↗
PubMed2003

Quantum state tomography of dissociating molecules.

Using tomographic reconstruction we determine the complete internuclear quantum state, represented by the Wigner function, of a dissociating I2 molecule based on femtosecond time resolved position and momentum distributions of the atomic fragments. The experimental data are recorded by timed ionization of the photofragments with an intense 20 fs laser pulse. Our reconstruction method, which relies on Jaynes's maximum entropy principle, will also be applicable to time resolved position or momentum data obtained with other experimental techniques.

Entropy↗
PubMed1972

The relative amounts and identification of some 2,4-dichlorophenoxyacetic Acid metabolites isolated from soybean cotyledon callus cultures.

Soybean (Glycine max L.) cotyledon callus grown on radioactive 2,4-dichlorophenoxyacetic acid (2,4-D-1-(14)C) as an auxin produced 2,4-D metabolites, which qualitatively and quantitatively changed with time. Water soluble fractions from the tissue exhibited a steady increase in radioactivity during the course of 24 days. Following beta-glucosidase treatment, at least eight aglycones were obtained from the water soluble fraction of the tissue after 8 days. The metabolite, 4-hydroxy-2,5-dichlorophenoxyacetic acid was the most abundant aglycone during the entire 32 day growth period while 4-hydroxy-2,3-dichlorophenoxyacetic acid was detected as a minor metabolite. Radioactivity in the ether soluble acidic fractions reached a maximum of 82% of the total in the tissue after 2 days. The level then decreased to 44% by the end of 24 days. A total of seven ether soluble components were detected. In addition to 2,4-D glutamic acid, which was detected in high amounts after 24 hours, 2,4-D aspartic acid was found to be the most abundant ether soluble metabolite after longer time periods. Mass spectral data and a fragmentation pattern are presented for 2,4-D aspartic acid.

Journal Article↗
PubMed1999

Three-centre C-H---O hydrogen bonds in the DNA minor groove: analysis of oligonucleotide crystal structures.

AA.TT and GA.TC dinucleotide steps in B-DNA-type oligomeric crystal structures and in protein-bound DNA fragments (solved using data with resolution <2.6 A) show very small variations in their local dinucleotide geometries. A detailed analysis of these crystal structures reveals that in AA.TT and GA.TC steps the electropositive C2-H2 group of adenine is in very close proximity to the keto O atoms of both the pyrimidine bases in the antiparallel strand of the duplex structure, suggesting the possibility of intra-base pair as well as cross-strand inter-base pair C-H---O hydrogen bonds in the DNA minor groove. The C2--H2---O2 hydrogen bonds in the A.T base pairs could be a natural consequence of Watson-Crick pairing. However, the cross-strand interactions between the bases at the 3'-end of the AA.TT and GA.TC steps obviously arise owing to specific local geometry of these steps, since a majority of the H2---O2 distances in both data sets are considerably shorter than their values in the uniform fibre model (3.3 A) and many are even smaller than the sum of the van der Waals radii. The analysis suggests that in addition to already documented features such as the large propeller twist of A.T base pairs and the hydration of the minor groove, these C2-H---O2 cross-strand interactions may also play a role in the narrowing of the minor groove in A-tract regions of DNA and help explain the high structural rigidity and stability observed for poly(dA).poly(dT).

Base Pairing↗
PubMed1997

A long-term survey of methicillin-resistant Staphylococcus aureus in the oral cavity of children.

Methicillin-resistant Staphylococcus aureus (MRSA), an indigenous bacteria in healthy people, often causes nosocomial infections. If the host human becomes compromised, MRSA can cause a serious infection. The long-term colonization of MRSA increases this risk. The purpose of this study was to demonstrate the incidence of S. aureus and MRSA colonization in the oral cavities of healthy children, and to examine the stability of identical strains of MRSA over a long-term period. Fourteen children were examined in two stages (first stage: 1987-88, second stage: 1992-93). Five of the 14 children were negative for S. aureus in both stages, seven children were positive in both stages and two children were positive in only the second stage. The children who were colonized with S. aureus in the first stage always harbored the bacteria in the second stage. Of the seven children that were positive for S. aureus in both stages, three persisted in carrying MRSA. We compared two MRSA strains isolated from the same children in both stages by coagulase typing, antibiogram typing and DNA fingerprinting. In two children, the strains showed the same coagulase types, similar antibiograms and similar DNA fragment profiles. These data strongly suggest that identical strains of MRSA persisted in the oral cavities for more than five years, and that the oral cavity can serve as a reservoir for MRSA with the potential to cause nosocomial infections.

Carrier State↗
PubMed1984

Structure of tumor-associated carbohydrate antigen Ca 19-9 on human seminal-plasma glycoproteins from healthy donors.

The monoclonal antibody-defined, tumor-associated antigen Ca 19-9, chemically identical with the sialylated Lewisa-carbohydrate determinant of a monoganglioside and a mucin, was demonstrated by radioimmunoassay to be present in large amounts as component of fucose-rich sialoglycoproteins, which had been extracted from human seminal plasma of healthy donors. The carbohydrate antigen of these glycoproteins (m greater than 205 kDa and m 115 kDa), which are presumably secreted by the prostatic gland, was absent in seminal plasma from blood-group-Lewis-negative men. The Ca 19-9 active sialyl-oligosaccharide was cleaved from the proteins by mild alkaline borohydride treatment and was shown to chromatograph on gradient elution from DEAE-Sephadex with the fraction of monosialylated saccharide alditols (MS-SP). The asialo derivative of the major saccharide alditol in this fraction was composed of L-fucose, D-galactose, N-acetyl-D-glucosamine and N-acetyl-D-galactosaminitol in the molar proportions 1:2:1:1 and chromatographed on Bio-Gel P2 according to approximately seven hexose units. A methylation analysis of the sialylated saccharide alditol in fraction MS-SP, which had been purified by high-pressure liquid chromatography, revealed the presence of terminal, non-reducing L-fucose, 3-O-substituted D-galactose, 3,4 di-O-substituted N-acetyl-D-glucosamine and 3-O-substituted N-acetyl-D-galactosaminitol. The presented data and the fragmentation pattern obtained on direct probe EI and FAB+ mass spectrometry of the permethylated asialo derivative are in accordance with the structure of a sialylated pentasaccharide alditol (formula; see text).

Adult↗
PubMed1996

Expression in Escherichia coli of Sin a 1, the major allergen from mustard.

Sin a 1, the major yellow mustard allergen, is a seed storage protein that belongs to the 2S albumin family. It is composed of two disulfide-bonded polypeptide chains. The cloning of this allergen has been carried out by means of the polymerase chain reaction using non-degenerate oligonucleotides encoding the N-terminal and C-terminal regions of the mature protein as primers. Five genomic nucleotide sequences have been analyzed, encoding both mature polypeptide chains linked by the internal processed fragment. The sequence data show the existence of microheterogeneities at ten positions, demonstrating the polymorphism exhibited by the natural protein. One of the genomic clones was expressed in Escherichia coli by fusion to glutathione S-transferase from Schistosoma japonicum. The resulting chimeric protein was purified by affinity chromatography on a glutathione-Sepharose 4B matrix, and digested with thrombin to release the recombinant allergen. The recombinant Sin a 1 is recognized by rabbit polyclonal and mouse monoclonal antisera raised against natural Sin a 1, as well as by the IgE of mustard-sensitive human sera. In addition, recombinant Sin a 1 possesses a high resistance to trypsin digestion, like the native mustard allergen.

Allergens↗
PubMed1997

Metabolic processing of gangliosides by human fibroblasts in culture--formation and recycling of separate pools of sphingosine.

Human cultured fibroblasts were fed with GM3 ganglioside species isotopically labeled at C3 of C18-sphingosine, or at C3 of C18-sphinganine, or at the sialic acid acetyl group, and with C18-sphingosine and C18-sphinganine, both labeled at C1. After a lipid pulse the cells were subjected until 7-day chase; measurements were then made of the radioactive products resulting from the administered long-chain base and ganglioside species catabolism and the salvage processes of catabolic fragments. From the data we drew the following conclusions. The GM3 species differing in the long-chain base structure were taken up by the cells and metabolized. About 80% of the total catabolic C18-sphingosine and C18-sphinganine were recycled for the biosynthesis of complex sphingolipids, the rest being degraded. Results obtained by administering ganglioside species of GM3 containing radioactive sphingosine or the free radioactive sphingosine to fibroblasts suggested the existence in the cells of two quite separate pools of sphingosine. One pool was the direct result of either the catabolism of radioactive GM3 high-density microdomains or the diffusion of exogenous sphingosine into the cell; this pool was mainly used for the biosynthesis of the GD3 species that contain palmitic and stearic acids. The other pool of sphingosine, the cell basal pool, came from the catabolism of radioactive sphingolipids in the recycling of sphingosine, and was used for the biosynthesis of the GD3 species that mainly contain very long fatty acid chains, the main fibroblast endogenous species of GD3. Administration of the ganglioside species of GM3 containing sphinganine or free sphinganine to fibroblasts yielded the GD3 species containing mainly very long-chain fatty acids and sphingosine. These results show the possible existence of a pool of ganglioside-derived sphingosine, quite separate from the cell basal pool of sphingosine, suggesting that sphingosine derived from sphingolipid catabolism is reduced to sphinganine before entering the sphingolipid biosynthetic pathway.

Autoradiography↗
PubMed1999

Effects of low oxygen condition on the generation of reactive oxygen species and the development in mouse embryos cultured in vitro.

OBJECTIVE(S): To elucidate the relationship between intracellular H2O2 production and embryo development in different oxygen culture conditions. METHODS: Pronuclear stage embryos were obtained from C57BL/CBA F1 and ICR mice. Measurement of H2O2 level was performed with 2',7'-dichlorodihydroflourescein diacetate and the number of blastomeres was counted after staining with 4',6'-diamidino-2-phenylindole. RESULTS: Regardless of strains, H2O2 level reached a peak at the 2-cell stage in 20% O2. But in embryos cultured in 5% O2 it was significantly lower at the 2-cell and 4-cell stages compared to those from 20% O2. The embryos cultured in 20% O2 showed developmental delay or block, but in 5% O2 these phenomena were overcome and the development was significantly increased with an infrequent fragmentation. CONCLUSIONS: Our data suggest that the 5% O2 decreases the relative concentration of H2O2 and results in improved embryo development in terms of quantity and quality without regard to type of strains.

Animals↗
PubMed1992

Antenatal diagnosis of haemophilia B by amplification and electrophoresis of an exon fragment with a short deletion.

Carrier identification and antenatal diagnosis were performed in 2 sisters by electrophoretic separation of the normal and abnormal bands obtained after amplification of a fragment of exon h in the factor IX gene. The mutation in the family had been characterised as an 8-base pair (bp) deletion in exon h. By amplification of a 326 bp fragment containing the site of deletion, the shorter 318 bp band of the haemophilia B gene could be separated by electrophoresis of the fragments. The comprehensive data collection at the Haemophilia Centre is of vital importance in the genetic counselling of haemophilia families, and was a crucial step for the successful diagnoses in these sisters.

Adult↗
PubMed2006

Differing molecular mechanisms appear to underlie early toxicity of prefibrillar HypF-N aggregates to different cell types.

Considerable attention has been paid to the high cytotoxic potential of small, prefibrillar aggregates of proteins/peptides, either associated or not associated with amyloid diseases. Recently, we reported that different cell types are variously affected by early aggregates of the N-terminal domain of the prokaryotic hydrogenase maturation factor HypF (HypF-N), a protein not involved in any disease. In this study, we provide detailed information on a chain of events triggered in Hend murine endothelial cells and IMR90 fibroblasts, which have previously been shown to be highly vulnerable or very resistant, respectively, to HypF-N aggregates. Initially, both cell lines displayed impaired viability upon exposure to HypF-N toxic aggregates; however, at longer exposure times, IMR90 cells recovered completely, whereas Hend cells did not. In particular, significant initial mitochondrial permeability transition (MPT) pore opening was found in IMR90 cells followed by a sudden repair of membrane integrity with rapid and efficient inhibition of cytochrome c and AIF release, and upregulation of Bcl-2. The greater resistance of IMR90 fibroblasts may also be due to a higher cholesterol content in the plasma membrane, which disfavours interaction with the aggregates. In contrast, Hend cells, which have less membrane cholesterol, showed delayed MPT opening with prolonged translocation of cytochrome c into the cytosol. Finally, the caspase 9 active fragment was increased significantly in both Hend and IMR90 cells; however, only Hend cells showed caspase 8 and caspase 3 activation with DNA fragmentation. From our data, the different responses of the two cell types to the same aggregates appear to be associated with two key events: (a) aggregate interaction with the plasma membrane, disfavoured by a high level of membrane cholesterol; and (b) alterations in mitochondrial functionality, leading to the release of pro-apoptotic stimuli, which are counteracted by upregulation of Bcl-2.

Adenosine Triphosphate↗
PubMedDate not supplied

Characterization of fragmented heavy-ion beams using a three-stage telescope detector: detector configuration and instrumentation.

Accelerated heavy-ion beams used in biological and medical research are often utilized in conjunction with absorbers which lead to the fragmentation of the beam. The BERKLET, initially a two-stage solid-state telescope detector, was designed to make rapid, on-line energy and linear energy transfer (LET) measurements of individual particles in a heavy-ion beam, thus allowing characterization of fragmented beams. From data collected with the BERKLET, one is able to determine a number of important parameters. These include: residual energy and LET histograms for the full beam and for the individual Z components, relative number of particles with a given Z, and dose and track average LET's for the full beam and for the individual Z's. Improvements to the BERKLET design and changes in data analysis are discussed and contrasted with the results of an earlier BERKLET configuration. The most notable improvements are the addition of a thin scintillation detector for improved LET measurement, a tenfold improvement in the dynamic range of the event discriminator, reported here as 1:2000, and dual high-and low-gain amplification of the LET signals, permitting the identification of particles with Z's ranging from 12 down to 1.

Energy Transfer↗
PubMed1989

Catalytic hydrolysis of vasoactive intestinal peptide by human autoantibody.

Vasoactive intestinal peptide (VIP) labeled with 125I, [Tyr10-125I]VIP, can be hydrolyzed by immunoglobulin G (IgG) purified from a human subject, as judged by trichloroacetic acid precipitation and reversed-phase high-performance liquid chromatography (HPLC). The hydrolytic activity was precipitated by antibody to human IgG, it was bound by immobilized protein G and showed a molecular mass close to 150 kilodaltons by gel filtration chromatography, properties similar to those of authentic IgG. The Fab fragment, prepared from IgG by papain treatment, retained the VIP hydrolytic activity of the IgG. Peptide fragments produced by treatment of VIP with the antibody fraction were purified by reversed-phase HPLC and identified by fast atom bombardment-mass spectrometry and peptide sequencing. The scissile bond in VIP deduced from these experiments was Gln16-Met17. The antibody concentration (73.4 fmol per milligram of IgG) and the Kd (0.4 nM) were computed from analysis of VIP binding under conditions that did not result in peptide hydrolysis. Analysis of the antibody-mediated VIP hydrolysis at varying concentrations of substrate suggested conformity with Michaelis-Menton kinetics (Km). The values for Km (37.9 X 10(-9) M) and the turnover number kcat (15.6 min-1) suggested relatively tight VIP binding and a moderate catalytic efficiency of the antibody.

Amino Acid Sequence↗
PubMed1996

Attomole protein characterization by capillary electrophoresis-mass spectrometry.

Electrospray ionization with an ultralow flow rate (</=4 nanoliters per minute) was used to directly couple capillary electrophoresis with tandem mass spectrometry for the analysis and identification of biomolecules in mixtures. A Fourier transform mass spectrometer provided full spectra (>30 kilodaltons) at a resolving power of approximately 60,000 for injections of 0.7 x 10(-18) to 3 x 10(-18) mole of 8- to 29-kilodalton proteins with errors of <1 dalton in molecular mass. Using a crude isolate from human blood, a value of 28,780.6 daltons (calculated, 28,780.4 daltons) was measured for carbonic anhydrase, representing 1 percent by weight of the protein in a single red blood cell. Dissociation of molecular ions from 9 x 10(-18) mole of carbonic anhydrase gave nine sequence-specific fragment ions, more data than required for unique retrieval of this enzyme from the protein database.

Animals↗
PubMed1994

Relationship between Phylogeny and Pathotype for the Bacterial Blight Pathogen of Rice.

Several transposable elements were isolated from the genome of Xanthomonas oryzae pv. oryzae. These elements and an avirulence gene isolated from X. oryzae pv. oryzae were used as hybridization probes for a collection of X. oryzae pv. oryzae strains from the Philippines. Each of the sequences was present in multiple copies in all strains examined and showed distinct patterns of hybridizing bands. Phenograms were derived from the restriction fragment length polymorphism data obtained for each of the individual probes and for pooled data from multiple probes. The phenograms derived from the different probes differed in topology and, on the basis of bootstrap analysis, were not equally robust. For all of the probes, including the avirulence gene, some groups (even some haplotypes) consisted of multiple races. The strains were grouped into four major clusters on the basis of the two probes giving the highest bootstrap values. These groups were inferred to represent phylogenetic lineages. Three of the six races of X. oryzae pv. oryzae appeared in more than one of the lineages, and another was present in two sublineages. For three of the races, strains representing different phenetic groups were inoculated on rice cultivars carrying 10 resistance genes. Two new races were differentiated, corresponding to pathogen lineages identified by DNA typing. On the basis of DNA and pathotypic analyses, together with information on the spatial and temporal distribution of the pathogen types from this and other studies, a general picture of X. oryzae pv. oryzae evolution in the Philippines is presented.

Journal Article↗