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Biomedical subjects

G A Smith

Publications and source records attributed to G A Smith.

At least 37 records · Page 2Linked to original sources
PubMed2001

Effectiveness of a pediatric trauma team protocol.

OBJECTIVE: To determine the effectiveness of a pediatric trauma triage system and resource allocation for emergency medicine and trauma services. TRAUMA SYSTEM: Two-tier trauma team activation system that triages patients into Level 1 and Level 2 trauma alert categories based on information provided by pre-hospital providers to pediatric emergency physicians at an American College of Surgeons' Level 1 pediatric trauma center in Columbus, Ohio. METHODS: Using the hospital trauma registry database and patient medical records, a retrospective chart review was conducted on all (n = 542) admitted pediatric trauma patients from January 1995 through December 1996. RESULTS: Level 1 patients had a higher median injury severity score and shorter emergency department (ED) length of stay time than Level 2 patients. Level 1 patients were more likely to be admitted to the pediatric intensive care unit and remain for more than 24 hours when compared to Level 2 patients. In addition, Level 1 patients were more likely to have procedures performed (eg, intubation, tube thoracostomy, thoracotomy, diagnostic peritoneal lavage) than Level 2 patients. The mortality rate was significantly higher for Level 1 patients and all ED deaths had been triaged to the Level 1 category. CONCLUSIONS: This pediatric trauma triage system effectively predicts which patients will be more likely to have serious injury. By using a two-tier system, select patients may be managed by a smaller trauma team, thus improving staff utilization and possibly reducing costs while ensuring favorable outcomes.

Child↗
PubMed2001

Lawn mower-related injuries to children.

Lawn mower-related injuries to children are relatively common and can result in severe injury or death. Many amputations during childhood are caused by power mowers. Pediatricians have an important role as advocates and educators to promote the prevention of these injuries.

Accident Prevention↗
PubMed2001

Technical report: lawn mower-related injuries to children.

In the United States, approximately 9400 children younger than 18 years receive emergency treatment annually for lawn mower-related injuries. More than 7% of these children require hospitalization, and power mowers cause a large proportion of the amputations during childhood. Prevention of lawn mower-related injuries can be achieved by design changes of lawn mowers, guidelines for mower operation, and education of parents, child caregivers, and children. Pediatricians have an important role as advocates and educators to promote the prevention of these injuries.

Accident Prevention↗
PubMed2001

Emerging viral diseases of Southeast Asia and the Western Pacific.

Over the past 6 years, a number of zoonotic and vectorborne viral diseases have emerged in Southeast Asia and the Western Pacific. Vectorborne disease agents discussed in this article include Japanese encephalitis, Barmah Forest, Ross River, and Chikungunya viruses. However, most emerging viruses have been zoonotic, with fruit bats, including flying fox species as the probable wildlife hosts, and these will be discussed as well. The first of these disease agents to emerge was Hendra virus, formerly called equine morbillivirus. This was followed by outbreaks caused by a rabies-related virus, Australian bat lyssavirus, and a virus associated with porcine stillbirths and malformations, Menangle virus. Nipah virus caused an outbreak of fatal pneumonia in pigs and encephalitis in humans in the Malay Peninsula. Most recently, Tioman virus has been isolated from flying foxes, but it has not yet been associated with animal or human disease. Of nonzoonotic viruses, the most important regionally have been enterovirus 71 and HIV.

Animals↗
PubMed2001

Potent anti-metastatic activity of combretastatin-A4.

The requirement for tumour vascularisation to permit the expansion of solid tumours beyond a threshold size of approximately 1 mm diameter has focussed attention on anti-vascular and anti-angiogenic agents for cancer therapy. Combretastatin-A4 (cis CA-4P) is a tubulin-binding agent that is cytotoxic for proliferating endothelial cells in vitro and causes anti-vascular effects in the established tumour vessels of some primary tumours. Preliminary data from Phase I clinical trials indicate that cis CA-4 may also be effective in targeting the vasculature of human tumours. As metastatic disease is the principal cause of mortality in cancer, we have investigated the effects of cis CA-4 on metastatic development using an in vivo model. We show that bolus or continuous administration of cis CA-4P results in potent inhibition of metastases derived from ectopic primary Lewis lung carcinomas in mice whereas the trans CA-4 isomer is without effect. These data further characterise the activity of CA-4 in vivo and suggest that the drug should be evaluated clinically as an anti-metastatic agent.

Animals↗
PubMed2001

The appearance of a second genotype of Japanese encephalitis virus in the Australasian region.

In mid-January 2000, the reappearance of Japanese encephalitis (JE) virus activity in the Australasian region was first demonstrated by the isolation of JE virus from 3 sentinel pigs on Badu Island in the Torres Strait. Further evidence of JE virus activity was revealed through the isolation of JE virus from Culex gelidus mosquitoes collected on Badu Island and the detection of specific JE virus neutralizing antibodies in 3 pigs from Saint Pauls community on Moa Island. Nucleotide sequencing and phylogenetic analyses of the premembrane and envelope genes were performed which showed that both the pig and mosquito JE virus isolates (TS00 and TS4152, respectively) clustered in genotype I, along with northern Thai, Cambodian, and Korean isolates. All previous Australasian JE virus isolates belong to genotype II, along with Malaysian and Indonesian isolates. Therefore, for the first time, the appearance and transmission of a second genotype of JE virus in the Australasian region has been demonstrated.

Animals↗
PubMed2001

Anterior cervicoplasty.

Explore the source record for details and available documents.

Dermatologic Surgical Procedures↗
PubMed2000

Australian bat lyssavirus infection: a second human case, with a long incubation period.

In December 1998, a 37-year-old Queensland woman died from a rabies-like illness, 27 months after being bitten by a flying fox (fruit bat). Molecular techniques enabled diagnosis of infection with Australian bat lyssavirus (ABL), the second human case to be recognised and the first to be acquired from a flying fox. It must be assumed that any bat in Australia could transmit ABL; anyone bitten or scratched by a bat should immediately wash the wounds thoroughly with soap and water and promptly seek medical advice.

Adult↗
PubMed2000

A self-recombining bacterial artificial chromosome and its application for analysis of herpesvirus pathogenesis.

A self-recombining bacterial artificial chromosome (BAC) containing the 142-kb pseudorabies virus genome was constructed such that the viral genome is rapidly excised from the BAC vector backbone on delivery into mammalian cells. The recombination is mediated by loxP sites in the plasmid and Cre recombinase encoded within the BAC vector. A synthetic intron inserted in the middle of the cre ORF completely inhibits recombination in Escherichia coli, but is spliced out after delivery of the plasmid into mammalian cells. Recombination is efficient, and pure virus lacking the BAC vector backbone is immediately isolated from transfected mammalian cells without the need of serial passage or plaque purification.

Amino Acid Sequence↗
PubMed2000

Estimation of systolic and diastolic free intracellular Ca2+ by titration of Ca2+ buffering in the ferret heart.

Spectroscopic Ca(2+)-indicators are thought to report values of free intracellular Ca(2+) concentration ([Ca(2+)](i)) that may differ from unperturbed values because they add to the buffering capacity of the tissue. To check this for the heart we have synthesized a new (19)F-labelled NMR Ca(2+) indicator, 1, 2-bis-[2-bis(carboxymethyl)amino-4,5-difluorophenoxy]ethane ('4, 5FBAPTA'), with a low affinity (K(d) 2950 nM). The new indicator and four previously described (19)F-NMR Ca(2+) indicators 1,2-bis-[2-(1 - carboxyethyl)(carboxymethyl)amino - 5 - fluorophenoxy]ethane ('DiMe-5FBAPTA'), 1, 2-bis-[2-(1-carboxyethyl)(carboxymethyl)amino-4-fluorophenoxy]ethane ('DiMe-4FBAPTA'), 1, 2-bis-[2-bis(carboxymethyl)amino-5-fluorophenoxy]ethane ('5FBAPTA') and 1, 2-bis-[2-bis(carboxymethyl)amino-5-fluoro-4-methylphenoxy]ethane ('MFBAPTA'), with dissociation constants for Ca(2+) ranging from 46 to 537 nM, have been used to measure [Ca(2+)](i), over the range from less than 100 nM to more than 3 microM, in Langendorff-perfused ferret hearts (30 degrees C, pH 7.4, paced at 1.0 Hz) by (19)F-NMR spectroscopy. Loading hearts with indicators resulted in buffering of the Ca(2+) transient. The measured end-diastolic and peak-systolic [Ca(2+)](i) were both positively correlated with indicator K(d). The positive correlations between indicator K(d) and the measured end-diastolic and peak-systolic [Ca(2+)](i) were used to estimate the unperturbed end-diastolic and peak-systolic [Ca(2+)](i) by extrapolation to K(d)=0 (diastolic) and to K(d)=infinity (systolic) respectively. The extrapolated values in the intact beating heart were 161 nM for end-diastolic [Ca(2+)](i) and 2650 nM for peak-systolic [Ca(2+)](i), which agree well with values determined from single cells and muscle strips.

Animals↗
PubMed2000

Ca2+ buffering in the heart: Ca2+ binding to and activation of cardiac myofibrils.

The measurement of cardiac Ca(2+) transients using spectroscopic Ca(2+) indicators is significantly affected by the buffering properties of the indicators. The aim of the present study was to construct a model of cardiac Ca(2+) buffering that satisfied the kinetic constraints imposed by the maximum attainable rates of cardiac contraction and relaxation on the Ca(2+) dissociation rate constants and which would account for the observed effects of (19)F-NMR indicators on the cardiac Ca(2+) transient in the Langendorff-perfused ferret heart. It is generally assumed that the Ca(2+) dependency of myofibril activation in cardiac myocytes is mediated by a single Ca(2+)-binding site on troponin C. A model based on 1:1 Ca(2+) binding to the myofilaments, however, was unable to reproduce our experimental data, but a model in which we assumed ATP-dependent co-operative Ca(2+) binding to the myofilaments was able to reproduce these data. This model was used to calculate the concentration and dissociation constant of the ATP-independent myofilament Ca(2+) binding, giving 58 and 2.0 microM respectively. In addition to reproducing our experimental data on the concentration of free Ca(2+) ions in the cytoplasm ([Ca(2+)](i)), the resulting Ca(2+) and ATP affinities given by fitting of the model also provided good predictions of the Ca(2+) dependence of the myofibrillar ATPase activity measured under in vitro conditions. Solutions to the model also indicate that the Ca(2+) mobilized during each beat remains unchanged in the presence of the additional buffering load from Ca(2+) indicators. The new model was used to estimate the extent of perturbation of the Ca(2+) transient caused by different concentrations of indicators. As little as 10 microM of a Ca(2+) indicator with a dissociation constant of 200 nM will cause a 20% reduction in peak-systolic [Ca(2+)](i) and 30 microM will cause approx. 50% reduction in the peak-systolic [Ca(2+)](i) in a heart paced at 1.0 Hz.

Adenosine Triphosphate↗
PubMed2000

An evaluation of a safety education program for kindergarten and elementary school children.

OBJECTIVE: To determine the effectiveness of a safety education program, Safety City, that is designed to teach kindergarten and first grade children how to cross the street, call 911 in an emergency, and avoid strangers. PARTICIPANTS/SETTING: Kindergarten students at 10 urban elementary schools. DESIGN: Each school was randomized to either the intervention or control group. An evaluation tool was administered to all participants as a pretest. The Safety City program was then presented to the intervention schools. Afterward, the same evaluation tool was used as a post-test. The posttest was administered to the intervention group 6 months after the Safety City program was presented. The control group took the posttest 6 months after the pretest. MAIN OUTCOME MEASURE: Change in individual test scores. RESULTS: One hundred eighty-one children completed the pretest and posttest evaluations. There was no statistical difference in the change between pretest and posttest scores of children who participated in the Safety City program and those in the control group (crossing the street, P = .29; calling 911, P = .41; stranger avoidance, P = .57). CONCLUSIONS: Exposure to the Safety City program did not achieve the desired changes in safety knowledge among participants. This is most likely owing to the fact that Safety City attempts to convey a large amount of relatively complex information to young children in a brief period. We conclude that programs such as Safety City are not sufficient to teach children these behaviors. This report also emphasizes the importance of building an evaluation component into educational programs.

Child↗
PubMed2000

Detection of Gov system antibodies by MAIPA reveals an immunogenicity similar to the HPA-5 alloantigens.

The glycosylphosphatidylinositol-linked platelet protein CD109 carries the biallelic alloantigen system Gov. There is limited information on the incidence of Gov alloantibodies in neonatal alloimmune thrombocytopenia (NAITP), post-transfusion purpura (PTP) and platelet refractoriness. We adapted the monoclonal antibody-specific immobilization of platelet antigens (MAIPA) assay to the detection of Gov antibodies and determined their incidence in 605 archived samples (112 with HPA antibodies) referred for the aforementioned conditions. Here, we show that CD109 expression was reduced upon platelet storage in saline or by cryopreservation, but was stable when stored as whole blood or therapeutic platelet concentrate. Fourteen of the 605 samples contained Gov alloantibodies (anti-Gova, n = 10; anti-Govb, n = 4), with the majority in platelet refractoriness (n = 9) and, of the remaining five, four in NAITP and one in PTP. In seven cases, no other HPA antibodies were detected, three being NAITP cases. The incidence of Gov antibodies was significantly lower than HPA-1 system antibodies (n = 87), but equalled the number of HPA-5 system antibodies (n = 14) and outnumbered HPA-2 and -3 system antibodies (10 altogether).

Alleles↗
PubMed1999

Reactivation of a macropodid herpesvirus from the eastern grey kangaroo (Macropus giganteus) following corticosteroid treatment.

The family Herpesviridae is a large group of viruses which contain double stranded DNA genomes. Biological characteristics, such as host signs, site of replication and site of latency have been used to describe three major subfamilies, Alphaherpesvirinae, Betaherpesvirinae and Gammaherpesvirinae within the family Herpesviridae. Macropodid herpesviruses (MaHV) have been implicated in fatal outbreaks amongst the captive marsupial populations of Australia. These outbreaks have resulted in the isolation of nine MaHV strains which have been classified into two species called macropodid herpesvirus 1 and 2 (MaHV-1 and MaHV-2). Biological characteristics have been used to place MaHV-1 and -2 within the subfamily Alphaherpesvirinae. Molecular phylogenetic reconstructions indicate an unusual position for MaHV-1 and -2 within the alphaherpesviruses. Current isolates of MaHVs have all been obtained from marsupials exhibiting clinical disease. A common biological characteristic of herpesviruses is the establishment of latent infections in nervous tissue. We have determined that MaHV are able to latently infect eastern grey kangaroos through reactivating and isolating a herpesvirus by inducing immunosuppression. We have investigated the possible sites of latency for MaHV-1 using molecular techniques. Detection of herpesvirus DNA in the trigeminal ganglia taken from two naturally infected eastern grey kangaroos indicates dissemination via a respiratory route.

Alphaherpesvirinae↗
PubMed1999

Molecular characterisation of Australian bovine enteroviruses.

In this study we report the full length (7.4 kb) sequence of two Australian bovine enterovirus (BEV) isolates, K2577 and SL305 and the partial sequence of a third isolate, 66/27, which are the prototypes of the three major serological groups of BEV in Australia. Australian BEV isolates have not previously been related to the international classification of BEV into the major serotypes BEV-1 and BEV-2. The sequences of the three representative Australian isolates were compared to the full length sequence of a Northern Ireland isolate (VG527) classified as BEV-1, as well as two partial sequences of isolates from the United States and the United Kingdom classified as BEV-2. All three Australian isolates were classified as BEV-1 on the basis of closer nucleotide and amino acid similarity to the 5'-UTR and capsid proteins of VG527 than to the BEV-2 isolates (79-81% versus 76-77% nucleotide identity in the 5-UTR, and 86-98% versus 65-77% amino acid identity in the capsid proteins). These results indicate that most if not all Australian BEV are BEV-1. The remainder of the genome, which encodes non-structural proteins involved in viral replication, showed high sequence homology as has been observed among such genes in other enteroviruses. A system for full-length amplification of BEV isolates was also developed and the K2577 isolate was cloned to obtain a full-length, infectious DNA copy of the BEV genome. When RNA transcripts of BEV amplification products were transfected into MDBK cells infectious particles were produced. These virus particles were identical to the original virus isolates. This system can be used as a basis for the development of BEV-vectored vaccines as well in further molecular studies of bovine enteroviruses.

Amino Acid Sequence↗
PubMed1999

Crystal structure of substrate complexes of methylmalonyl-CoA mutase.

X-ray crystal structures of methylmalonyl-CoA mutase in complexes with substrate methylmalonyl-CoA and inhibitors 2-carboxypropyl-CoA and 3-carboxypropyl-CoA (substrate and product analogues) show that the enzyme-substrate interactions change little during the course of the rearrangement reaction, in contrast to the large conformational change on substrate binding. The substrate complex shows a 5'-deoxyadenine molecule in the active site, bound weakly and not attached to the cobalt atom of coenzyme B12, rotated and shifted from its position in the substrate-free adenosylcobalamin complex. The position of Tyralpha89 close to the substrate explains the stereochemical selectivity of the enzyme for (2R)-methylmalonyl-CoA.

Binding Sites↗