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Biomedical subjects

G A Smith

Publications and source records attributed to G A Smith.

At least 19 recordsLinked to original sources
PubMed1995

Epidemiology of shopping cart-related injuries to children. An analysis of national data for 1990 to 1992.

OBJECTIVE: To describe the epidemiologic characteristics of shopping cart-related injuries among children in the United States. DESIGN: A retrospective analysis of data from the National Electronic Injury Surveillance System of the US Consumer Product Safety Commission for 1990 to 1992. RESULTS: An estimated 75,200 shopping cart-related injuries occurred in children younger than 15 years treated in US emergency departments during 1990 to 1992 (95% confidence interval, 57,500 to 92,900). Children younger than 5 years were at highest risk, accounting for 63,200 (84%) of the injuries. A 20% increase was observed in the number of injuries among 0- to 4-year-old children from 1990 to 1992. Fifty-three percent of injured children were male. The head and neck region was the most common anatomic site of injury, accounting for 74% of injuries among children younger than 15 years. An estimated 2000 children (2.7%) younger than 15 years required hospital admission (1.2% in 1990 compared with 3.5% in 1992). Children aged 0 to 4 years accounted for 93% of these hospital admissions. Among 0- to 14-year-old children, fractures accounted for 45% of hospital admissions, followed by internal injury (22%) and concussion (17%). CONCLUSIONS: Injuries related to shopping carts are an important cause of pediatric morbidity, especially among children younger than 5 years. These injuries can also result in death. Shopping carts should be redesigned to decrease the risk of injury to children, and transportation of children in shopping carts of current design should be prohibited.

Accidental Falls↗
PubMed1995

Iontophoretic delivery of oligonucleotides across full thickness hairless mouse skin.

In recent years there has been an increased interest in the use of oligonucleotides as therapeutic agents. Oligonucleotide therapeutics may have significant potential over traditional drugs due to their high degree of specificity and increased affinity. The major drawbacks to the use of oligonucleotide therapeutics are the problems associated with their delivery and their relative instability in serum. The serum instability problem has been partially overcome through the use of oligonucleotides with modified backbones. Transdermal electrotransport may be used to overcome the problems associated with delivery. Here we report the use of transdermal electrotransport in the delivery of oligonucleotides across hairless mouse skin. The effects of pH, salt concentration, current density, and oligonucleotide concentration, structure, and length have been investigated.

Administration, Cutaneous↗
PubMed1995

Electrical injuries in a pediatric emergency department.

STUDY OBJECTIVE: To examine the spectrum of electrical injuries and develop guidelines for management. DESIGN: Retrospective review of charts compiled during a 6-year period (1988 through 1993). SETTING: Pediatric emergency department. PARTICIPANTS: Seventy-eight patients seen for electrical injuries. RESULTS: Fifty-four percent of patients were boys, and the mean age of the patients was 5.3 years. Eighty-two percent sustained burns. We divided patients into those who were involved in major electrical current events (n = 8) (water contact and high voltage) and minor electrical current events (n = 70) (injury sustained while placing an object in an outlet or touching/plugging in a cord or during oral contact with a cord). Of the minor events, all burns (n = 61) involved less than 1% of body surface area. Eighteen patients sustained second-degree burns, and 19 sustained third-degree burns. Of the eight major-event patients, one had abnormal ECG/rhythm strip findings, two had abnormal urinalysis results, and six had abnormal levels of creatine phosphokinase. All eight were admitted. Of the 70 minor-event patients, 2 of 53 had abnormal ECG/rhythm strip findings, 1 of 48 had abnormal urinalysis results, and 2 of 40 had abnormal creatine phosphokinase levels. Thirty-six of the 70 minor-event patients were admitted. Patients involved in major events were more likely to undergo studies (P = .002), to have an abnormal result (P = .000008), and to be hospitalized (P = .008). In minor-event patients, hospitalization was limited to observation and the fitting of oral appliances. CONCLUSION: Children involved in electrical events are usually exposed to low-voltage household current resulting in minor injury. Asymptomatic children with minor electrical injuries do not require laboratory evaluation or hospitalization.

Accidents, Home↗
PubMed1995

The two distinct phospholipases C of Listeria monocytogenes have overlapping roles in escape from a vacuole and cell-to-cell spread.

Listeria monocytogenes secretes two distinct phospholipases C, a phosphatidylinositol-specific phospholipase C (PI-PLC) and a broad-range phospholipase C (PC-PLC). In this study, single in-frame deletion mutants with mutations in each PLC and a double mutant lacking both PLCs were characterized with regard to virulence in mice, escape from a primary vacuole, and cell-to-cell spread in cell culture. The mutant lacking PI-PLC, previously shown to be twofold less virulent than the wild type in mice, had a minor defect in escape from a primary vacuole but was not notably affected in cell-to-cell spread. The mutant lacking PC-PLC was 20-fold less virulent in mice and was defective in cell-to-cell spread but had no measurable defect in escape from a primary vacuole. The mutant lacking both PLCs was 500-fold less virulent in mice and was severely diminished in its ability to escape from the primary vacuole and to spread cell to cell. Cellular levels of diacylglycerol and ceramide, products of PLC activity, accumulated beginning 3 to 4 h after infection of cells with wild-type bacteria. The bacterial PLCs were partially responsible for this activity, since cells infected with the mutant lacking both PLCs had a reduced increase in diacylglycerol and no increase in ceramide. Elevation of diacylglycerol in the absence of bacterial PLCs indicated that host cell phospholipase(s) was activated during infection. The results of this study were consistent with the two bacterial PLCs having overlapping functions throughout the course of intracellular infection. Furthermore, the PC-PLC, and possibly PI-PLC, appeared to be enzymatically active intracellularly.

Animals↗
PubMed1995

Current status of vinorelbine for breast cancer.

Vinorelbine tartrate (Navelbine) is a new semisynthetic vinca alkaloid with efficacy against a variety of solid tumors, including non-small-cell lung cancer, breast cancer, head and neck cancer, and Hodgkin's lymphoma. Recently approved by the FDA for the first-line treatment of advanced non-small-cell lung cancer, vinorelbine is also under review by the FDA for use in patients with metastatic breast cancer. There is now extensive data confirming the activity of vinorelbine in metastatic breast cancer, with second-line response rates of 17% to 36% and first-line response rates of 40% to 44%. Investigators have combined vinorelbine with other active drugs against breast cancer to produce response rates exceeding 50% for first-line therapy. Numerous centers are now conducting randomized trials comparing vinorelbine to established second-line therapies for advanced breast cancer, such as paclitaxel (Taxol). Future research is needed to further define the precise role of vinorelbine as a component of combination therapy for metastatic breast cancer.

Administration, Oral↗
PubMed1992

Cloning and characterization of a gene encoding extracellular metalloprotease from Streptomyces lividans.

The prt gene, encoding a protease (Prt) from Streptomyces lividans TK24, was cloned and sequenced. An S. lividans host with plasmid-borne prt secreted 200 micrograms/ml of a 22-kDa Prt into the culture medium. Prt is classified as a metalloprotease since its activity is significantly inhibited by 1,10-phenanthroline or EDTA. The region upstream from prt codes for an incomplete open reading frame (ORF) oriented opposite to prt. This ORF has a strong similarity to a gene family (lysR) whose members regulate the transcription of structural genes required for either biosynthesis or degradation.

Amino Acid Sequence↗
PubMed1992

The effect of clinical use and sterilization on selected orthodontic arch wires.

The effect of clinical use and various sterilization/disinfection protocols on three types of nickel-titanium, and one type each of beta-titanium and stainless steel arch wire was evaluated. The sterilization/disinfection procedures included disinfection alone or in concert with steam autoclave, dry heat, or cold solution sterilization. No clinically significant differences were found between new and used arch wires. The direction of load application to the arch wire and the particular segment of arch wire tested was found to cause substantial differences in generated loads for certain arch wire types.

Analysis of Variance↗
PubMed1992

An allometric-autoregressive approach to poultry development.

1. The relative rates of development in a commercial layer and a broiler strain of chicken fed 180 or 230 g crude protein/kg were investigated by the use of the allometric-autoregressive model. Development was divided into pre-pubertal (0 to 8 weeks) and pubertal phases (8 to 22 weeks). 2. Significant strain effects were observed, at all ages, in rates of gain of live (L) body mass, carcass (C) mass, non-carcase (N) mass and empty-body (EB) mass as well as C, N and EB moisture, protein and fat content. 3. Significant dietary effects were observed in C and EB fat in the pre-pubertal phase and L mass, N protein and C fat in the subsequent pubertal period.

Adipose Tissue↗
PubMed1992

Platelet counting using plasma platelet concentrate samples.

Platelet counting using samples of plasma from platelet concentrates prepared for transfusion was assessed. The methods employed included a manual phase-contrast method, and counting with Coulter S Plus and Sysmex E-2500 counters. All methods were reproducible (mean CV of 4.9, 2.2 and 1.4%, respectively). However, neat samples of platelet concentrates analysed by Coulter counter were inaccurate (mean count of 863.8 x 10(9)/l compared to 1018.9 x 10(9)/l counted manually). Moreover, the Coulter platelet counts were non-linear above 900 x 10(9)/l, whereas the E-2500 platelet counts were linear to 2700 x 10(9)/l. A one-in-three pre-dilution was required to obtain accurate, linear counts with the Coulter counter, whereas the E-2500 was accurate without pre-dilution (mean count of 1030.2 x 10(9)/l compared to 1018.9 x 10(9)/l counted manually). In conclusion, the method of platelet counting may affect true platelet yields.

Automation↗
PubMed1992

A light microscopical study of the intestinal tract of the Nile crocodile (Crocodylus niloticus, Laurenti 1768).

Although the histology of the intestinal tract of Crocodylus niloticus is touched on in overall studies on reptilian intestinal tract, a more comprehensive light microscopical study on this area is lacking. Specimens for histological examination were taken from the duodenum, the jejunum, the ileum and the rectum. The data obtained revealed that the mucosa is thrown into folds and simple, slightly branched tubular intestinal glands. The mucosal folds diminished in height and eventually disappeared upon reaching the ileorectal junction. The epithelium covering the folds and crypts was of the simple columnar type. Clear marginal cells, goblet cells and argentaffin cells were observed throughout the intestinal tract. No Paneth cells were seen in this study. The lamina propria was rich in lymphocytic infiltrations while the muscularis mucosa consisted mainly of an outer longitudinal layer, the inner circular layer being rudimentary or absent. The submucosa was extremely narrow, and the circular and longitudinal layers of the tunica muscularis contained distinct layers of dense fibrous connective tissue. The histology of the intestinal tract of C. niloticus is shown to be in line with the situation in crocodilians and also exhibits a resemblance to that of carnivorous mammals.

Alligators and Crocodiles↗
PubMed1992

Biomechanical analysis of cross-country skiing techniques.

The development of new techniques for cross-country skiing based on skating movements has stimulated biomechanical research aimed at understanding the various movement patterns, the forces driving the motions, and the mechanical factors affecting performance. Research methods have evolved from two-dimensional kinematic descriptions of classic ski techniques to three-dimensional analyses involving measurement of the forces and energy relations of skating. While numerous skiing projects have been completed, most have focused on either the diagonal stride or the V1 skating technique on uphill terrain. Current understanding of skiing mechanics is not sufficiently complete to adequately assess and optimize an individual skier's technique.

Biomechanical Phenomena↗
PubMed1992

Bioactive peptides and serotonin in the gut endocrine cells of the crocodile, Crocodylus niloticus (Laurenti 1768): an immunocytochemical study.

Little is known about peptide-storing endocrine cells in the gut of the Nile crocodile. As in the case of other reptiles, particularly the alligator, a limited range of peptide-storing cells was found in the gut of the crocodile. They were somatostatin, glucagon, gastrin, neurotensin and pancreatic polypeptide. The topographical distribution of cells immunoreactive to somatostatin and gastrin in the gut of the crocodile is comparable to the situation in the alligator. Glucagon and neurotensin immunoreactive cells have a much wider distribution in the gastro-intestinal tract of the crocodile compared to the alligator. Cholecystokinin and bombesin cells previously reported in the small intestine of the alligator were not detected in this study. This is the first report to demonstrate pancreatic polypeptide and serotonin immunoreactivity in the gut of a crocodilian specie.

Alligators and Crocodiles↗
PubMed1992

Influence of phased inclusion of halofuginone on broiler skin tensile strength and growth performance.

The effect of continuous administration, weekly 24 h administration, phased withdrawal and phased inclusion of dietary halofuginone at 3 mg kg-1 on skin tensile strength was tested in Ross I broiler pullets. Controls received monensin continuously at 100 mg kg-1. A total of 2,592 birds were used in 2 lots of 1,296 in 2 separate programmes. Continuous dietary administration of halofuginone affected skin tensile strength negatively (P less than 0.05), with an equally significant recovery following a 7 d withdrawal period. A polynomial regression analysis indicates that skin strength may undergo a slight compensatory overstrengthening reaction within 7 d of withdrawal of halofuginone. Weekly 24 h administration of halofuginone reduced differences in skin strength between treatment and controls to non-significant levels. Differences in skin strengths between controls and the halofuginone phased inclusion programme decreased as the birds aged, being significant (P less than 0.05) on Days 14 and 28 and non-significant on Days 21, 35, 42 and 49. A weakening of skin tensile strength of broiler carcasses, as far as it may be influenced by halofuginone, can be alleviated through different shuttle programmes involving halofuginone. Such programmes would include intermittent dosing, a withdrawal period, administration to older birds or a combination of these programmes.

Animals↗
PubMed1992

Influence of continuous dietary halofuginone on broiler skin tensile strength and growth performance.

Halofuginone was administered to both sexes of 2 broiler strains, Ross and Hubbard, in 4 dietary treatments, 0, 1.5, 3 and 6mg kg-1. Controls received dietary monensin at 100 mg kg-1. Group feed intake and body mass were recorded weekly. Skin tensile strength was monitored on Days 28, 35, 42 and 49 using a standardised cut of breast skin from carcasses randomly drawn from each treatment, strain and sex combination. Halofuginone inclusion level was inversely correlated (r = -0.36) with skin tensile strength and affected both sexes of the 2 strains (P less than 0.01). Between sexes, the skins of cockerels were consistently stronger than those of hens (P less than 0.01). The effect of age (P less than 0.07) and that of strain (P less than 0.06) tended towards significance at the 5% level. The singular effect of halofuginone on skin tensile strength was masked by the interactions treatment and sex (P less than 0.01); treatment and age (P less than 0.02); treatment and strain (P less than 0.06); age and strain (P less than 0.01). An inclusion level of 6mg kg-1, double the recommended level, could reduce growth and skin tensile strength significantly.

Animals↗
PubMed1991

The origin of multiply sigmoid curves of pH-dependence. The partitioning of groups among titration pK values.

An acid, HnA, with n ionizing groups is known to have the same titration curve as an equimolar mixture of n hypothetical monobasic acids, whose dissociation constants are known as the 'titration constants' of the real acid. We show that the pH-dependence of any property of HnA is also represented by the sum of one-site titration curves, characterized by these same titration constants. Since one such property is the degree of dissociation of one of the dissociating groups, a fraction of each group shows each of the various titration pK values, so that the group partitions among them. The n groups therefore share the same n titration pK values but differ in the fractions belonging to each. The one H+ ion per molecule that titrates with each pK is thus made up of the fractions, one from each group, that share this pK value. A group may possess a single pK value, in that it contributes virtually all of this pK and almost nothing to the others, only if either (1) in titrates in a different pH range from the other groups or (2) its affinity for H+ is unaffected by their ionization state.

Acids↗
PubMed1991

An acetylation method for the quantification of membrane lipids, including phospholipids, polyphosphoinositides and cholesterol.

A method for the quantification of membrane lipids by acetylation with [3H]acetic anhydride is described. A standard lipid, labelled with 14C or 32P, is added to the sample and is simultaneously acetylated. The 3H/14C or 3H/32P ratios obtained in the acetylated lipids are proportional to the initial lipid concentration. The method has been used to quantify cholesterol, phosphatidylethanolamine, phosphatidylinositol, sphingomyelin, phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate in amounts between 2 and 10 nmol.

Acetylation↗
PubMed1991

Nucleotide and amino acid sequence analysis of the thymidine kinase gene of a bovine encephalitis herpesvirus.

The nucleotide and predicted amino acid sequence of the thymidine kinase (TK) gene of N 569, a bovine encephalitis herpesvirus (BEHV), has been determined and compared with those of avian, bovine and other mammalian herpesvirus TK genes. Striking differences were observed between the nucleotide sequence of this BEHV TK gene and those reported for bovine herpesvirus 1 (BHV-1). A total of 118 base changes, 39 base deletions and 14 base insertions were identified relative to the TK sequence of a BHV-1.2a strain, resulting in a net loss of seven residues. Comparison of the TK sequences of BEHV and the BHV-1 Q 3932 strain with that reported for the BHV-1 6660 strain suggested that the latter may have contained sequencing errors. The most significant difference between the BEHV TK sequence and those of BHV-1 strains was the absence of a contiguous stretch of ten codons.

Amino Acid Sequence↗