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Biomedical subjects

L Sims

Publications and source records attributed to L Sims.

At least 19 recordsLinked to original sources
PubMed2006

Epidemiology and ecology of highly pathogenic avian influenza with particular emphasis on South East Asia.

Highly pathogenic avian influenza (HPAI) has been recognised as a serious viral disease of poultry since 1878. The number of recorded outbreaks of HPAI has increased globally in the past 10 years culminating in 2004 with the unprecedented outbreaks of H5N1 HPAI involving at least nine countries in East and South-East Asia. Apart from the geographical extent of these outbreaks and apparent rapid spread, this epidemic has a number of unique features, among which is the role that asymptomatic domestic waterfowl and more particularly free-ranging ducks play in the transmission of highly pathogenic H5N1. Field epidemiological studies have been conducted by the Food and Agriculture Organization and several collaborative centres to explore the factors that could have led to a change from infection to the emergence of widespread disease in 2003-2004 and 2005. Domestic waterfowl, specific farming practices and agro-ecological environments have been identified to play a key role in the occurrence, maintenance and spread of HPAI. Although there are some questions that remain unanswered regarding the origins of the 2004 outbreaks, the current understanding of the ecology and epidemiology of the disease should now lead to the development of adapted targeted surveillance studies and control strategies.

Agriculture↗
PubMed2003

The impact of a monthly rest day on avian influenza virus isolation rates in retail live poultry markets in Hong Kong.

Retail live poultry markets (LPMs) may act as a reservoir of avian influenza viruses (AIV). In this study we test the hypothesis that a rest day in the LPMs where the stalls are completely emptied of poultry, cleansed, and restocked will reduce the isolation rates of avian influenza viruses. The isolation rate of H9N2 subtype viruses from chicken was significantly lower after the rest day than prior to it, indicating its impact in reducing transmission. In contrast, Newcastle disease virus (NDV) isolation rates appear unaffected by this intervention, possibly reflecting differences in herd immunity or virus transmission dynamics.

Animals↗
PubMed2003

Reassortants of H5N1 influenza viruses recently isolated from aquatic poultry in Hong Kong SAR.

The H5N1 virus (H5N1/97) that caused the bird flu incident in Hong Kong in 1997 has not been isolated since the poultry slaughter in late 1997. But the donor of its H5 hemagglutinin gene, Goose/Guangdong/1/96-like (Gs/Gd/96-like) virus, established a distinct lineage and continued to circulate in geese in the area. In 2000, a virus from the Goose/Guangdong/1/96 lineage was isolated for the first time from domestic ducks. Subsequently, it has undergone reassortment, and these novel reassortants now appear to have replaced Gs/Gd/96-like viruses from its reservoir in geese and from ducks. The internal gene constellation is also different from H5N1/97, but these variants have the potential for further reassortment events that may allow the interspecies transmission of the virus.

Animals↗
PubMed2001

Insecticidal proteins from Bacillus thuringiensis protect corn from corn rootworms.

Field tests of corn co-expressing two new delta-endotoxins from Bacillus thuringiensis (Bt) have demonstrated protection from root damage by western corn rootworm (Diabrotica virgifera virgifera LeConte). The level of protection exceeds that provided by chemical insecticides. In the bacterium, these proteins form crystals during the sporulation phase of the growth cycle, are encoded by a single operon, and have molecular masses of 14 kDa and 44 kDa. Corn rootworm larvae fed on corn roots expressing the proteins showed histopathological symptoms in the midgut epithelium.

Animals↗
PubMed2000

Molecular analysis of the SCARECROW gene in maize reveals a common basis for radial patterning in diverse meristems.

Maize and Arabidopsis root apical meristems differ in several aspects of their radial organization and ontogeny. Despite the large evolutionary distance and differences in root radial patterning, analysis of the putative maize ortholog of the Arabidopsis patterning gene SCARECROW (SCR) revealed expression localized to the endodermis, which is similar to its expression in Arabidopsis. Expression in maize extends through the quiescent center, a population of mitotically inactive cells formerly thought to be undifferentiated and to lack radial pattern information. Zea mays SCARECROW (ZmSCR), the putative maize SCR ortholog, was used as a molecular marker to investigate radial patterning during regeneration of the root tip after either whole or partial excision. Analysis of the dynamic expression pattern of ZmSCR as well as other markers indicates the involvement of positional information as a primary determinant in regeneration of the root radial pattern.

Amino Acid Sequence↗
PubMed2000

Outbreak of nosocomial infections due to extended-spectrum beta-lactamase-producing strains of enteric group 137, a new member of the family Enterobacteriaceae closely related to Citrobacter farmeri and Citrobacter amalonaticus.

A member of the Enterobacteriaceae initially identified as Kluyvera cryocrescens by the MicroScan Gram-Negative Combo 13 panel caused an outbreak of nosocomial infections in four patients (pneumonia, n = 2; urinary tract infection, n = 1; wound infection, n = 1) and urinary tract colonization in one patient. When the strains were tested by the Enteric Reference Laboratory of the Centers for Disease Control and Prevention, biochemical results were most compatible with Yersinia intermedia, Kluyvera cryocrescens, and Citrobacter farmeri but identification scores were low and test results were discrepant. However, when the biochemical test profile was placed in the computer database as a new organism, all strains were identified as the organism with high identification scores (0. 999968 to 0.999997) and no discrepant test results. By 16S rRNA sequence analysis the organism clustered most closely with, but was distinct from, Citrobacter farmeri and Citrobacter amalonaticus. Based on its unique biochemical profile and rRNA sequence, this organism is designated Enteric Group 137. Restriction endonuclease analysis and taxonomic antibiograms of strains causing the outbreak demonstrated a single clone of Enteric Group 137, and antibiotic susceptibility testing revealed the presence of extended-spectrum beta-lactamase (ESBL) resistance. Enteric Group 137 appears to be a new opportunistic pathogen that can serve as a source of ESBL resistance in the hospital.

Aged↗
PubMed1998

Characterization of avian H5N1 influenza viruses from poultry in Hong Kong.

The transmission of avian H5N1 influenza viruses to 18 humans in Hong Kong in 1997 with six deaths established that avian influenza viruses can transmit to and cause lethal infection in humans. This report characterizes the antigenic and biological properties of the H5N1 influenza viruses isolated from chickens, ducks, and geese from farms and poultry markets in Hong Kong during 1997 and compares them with those of virus isolated from the index human case. Each of the H5N1 viruses from Hong Kong poultry markets that were tested were lethal in chickens, possessed polybasic amino acids at the carboxy-terminus of HA1, and by definition were highly pathogenic in poultry. The available nonpathogenic H5 influenza viruses and the pathogenic H5N1 virus from Hong Kong were analyzed with monoclonal antibodies prepared to A/chicken/Pennsylvania/1370/83 (H5N2). The analysis revealed limited antigenic drift in 15 years and established that monoclonal antibodies are useful reagents for identification and antigenic analysis of avian strains that may transmit to humans in the future. One of the monoclonal antibodies permitted separation of the H5N1 influenza viruses from poultry into two groups that correlated with the presence or absence of a carbohydrate at residue 158 adjacent to the receptor binding site on HA. The H5N1 viruses examined replicated in geese, pigs, rats, and mice, but to only a very limited extent in ducks. It is noteworthy that all infected geese shed virus and that the H5N1 viruses caused disease signs and death in a portion (3 of 16) of the geese, with evidence of systemic spread to the brain. The tropism for geese is unusual and may provide insight into the origin of these viruses. In mice, the H5N1 virus caused lethal pneumonia and spread systemically to the brain. Mice would thus provide an ideal model system for studying immune responses and pathogenesis. Transmission experiments in chickens revealed that the H5N1 viruses are spread by fecal-oral transmission rather than by aerosol, and that the viruses are inactivated by drying of feces at ambient temperature. However, infectivity is maintained for at least 4 days in wet feces at 25 degreesC. There were differences in the morphology of the H5N1 viruses isolated from birds and humans. The perpetuation of H5N1 influenza viruses in the poultry markets in Hong Kong and the transmission of these viruses to humans emphasize the importance of these markets in the epidemiology of influenza. The poultry markets are of critical importance in the perpetuation and transmission of influenza viruses to other avian species and to mammals, including humans.

Animals↗
PubMed1996

North American Multicenter Study on flow cytometric enumeration of CD34+ hematopoietic stem cells.

Transplant centers often rely on CD34+ cell quantitation by flow cytometry to ensure adequacy of hematopoietic progenitor cell collection. Because of variation in interpretation, a lack of interlaboratory proficiency studies, and no generally accepted methodology, comparison of CD34 data from site to site is difficult. Twenty-one samples from marrow and peripheral blood stem cell collections were shipped to 10 participating North American laboratories for analysis. Duplicate samples were included to assess reproducibility. Participants were surveyed for methodology. Three centers had previously attempted to standardize their methodology among themselves. The variability observed in the CD34 values ranged from a max/min. reported value per sample of 2.9 to 749 (median 76). Exclusion of two outlying sites reduced the variability of results to 1.2 to 27 (median 3.1). Variation among the three standardized sites ranged from 1.2 to 4.4 (median 1.6). Overall reproducibility (excluding the outlying sites B and G) ranged from a minimum of 0-16.5 (percent mean difference) for site C to a maximum of 4.1-133 for site H. Strategies for gating were found to largely influence results. We observed an alarming variation among the CD34 cell counts reported from different laboratories. Standardization substantially reduced observed variation. The need for standardized methodology, reporting, quality control, and proficiency testing is underscored by these findings.

Antigens, CD34↗
PubMed1992

Microprojectile bombardment of plant tissues increases transformation frequency by Agrobacterium tumefaciens.

Bombardment of plant tissues with microprojectiles in an effective method of wounding to promote Agrobacterium-mediated transformation. Tobacco cv. Xanthi leaves and sunflower apical meristems were wounded by microprojectile bombardment prior to application of Agrobacterium tumefaciens strains containing genes within the T-DNA encoding GUS or NPTII. Stable kanamycin-resistant tobacco transformants were obtained using an NPTII construct from particle/plasmid, particle-wounded/Agrobacterium-treated or scalpel-wounded/Agrobacterium-treated potato leaves. Those leaves bombarded with particles suspended in TE buffer prior to Agrobacterium treatment produced at least 100 times more kanamycin-resistant colonies than leaves treated by the standard particle gun transformation protocol. In addition, large sectors of GUS expression, indicative of meristem cell transformation, were observed in plants recovered from sunflower apical explants only when the meristems were wounded first by particle bombardment prior to Agrobacterium treatment. Similar results in two different tissue types suggest that (1) particles may be used as a wounding mechanism to enhance Agrobacterium transformation frequencies, and (2) Agrobacterium mediation of stable transformation is more efficient than the analogous particle/plasmid protocol.

Agrobacterium tumefaciens↗
PubMed1991

The days ahead.

How are government controls affecting healthcare foodservices?Are growing elderly & outpatient populations changing foodservices' missions. What are the hottest trends? As members of the American Society for Hospital Food Service Administrators prepared for their annual meeting in Orlando, FM queried 11 Southeastern directors to learn their most pressing concerns & how they are positioning their departments for the future.

Aged↗
PubMed1984

Streptococcus durans: an unexpected enteropathogen of foals.

Streptococcus durans was isolated from a foal with profuse watery diarrhea and caused a similar syndrome when inoculated into foals via the orogastric route. The most consistent and striking histological feature was the extensive colonization of the mucosal surface of the small intestine by S. durans. Associated mucosal changes were mild to modeate, and brush border lactase and alkaline phosphatase production were depressed. S. durans also induced acute diarrhea in young gnotobiotic piglets. Mucosal changes were mild and, as with foals, the mucosal surface of the small intestine was colonized by the organism.

Animals↗
PubMed1982

Nutrition knowledge and attitudes of elementary school students after receiving nutrition education.

The effect of a nine-week nutrition education program on nutrition knowledge and selected nutrition/food attitudes of kindergarten through sixth grade pupils was examined. Children in the experimental group participated in the program for a nine-week instructional period; those in the control group participated later. Knowledge and attitude assessment instruments were administered to both groups immediately before and after the instructional period. In the lower grades (kindergarten through grade 3), responses on two of the three attitude scales were positively influenced by the nutrition education program. On the third attitude scale there was a trend toward a positive effect in all but one of the lower grades, but the trend was significant only in first grade. In the upper grade levels (4 through 6), the effect of nutrition education on the nutrition and food attitude scale responses was mixed; it tended to be most positive in grade 4 and least positive in grade 6. The nutrition education program also had a significant positive effect on the nutrition knowledge score of pupils in all grades except sixth. In this grade, the trend was positive but was not significant.

Attitude to Health↗