Head and neck melanoma.
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Head and Neck Neoplasms↗
Biomedical subjects
J F Smith
Publications and source records attributed to J F Smith.
Identification of a TFIIIA binding site on the 5' flanking region of the TFIIIA gene.
Xenopus transcription factor IIIA (TFIIIA) regulates 5S ribosomal RNA gene transcription in a positive manner by binding to the internal control region (ICR) of the 5S RNA gene. The present study reports the identification of a TFIIIA binding site on the 5' flanking region of the Xenopus laevis gene that codes for the synthesis of this transcription factor. This TFIIIA binding site (deduced from TFIIIA-dependent alterations in DNase I protection patterns) extends on the 5' flanking region from about nucleotide -326 to -264 on the non-coding strand and from -331 to -271 on the coding strand. The affinity of TFIIIA for the 5' flanking region of its own gene is less than that for the 5S RNA gene but within the same order of magnitude. A sequence similarity between this newly identified binding site and the 5S gene ICR is the presence of purine-rich tracts. EDTA chelation of TFIIIA inhibits binding to this 5' flanking element indicating, as with the 5S RNA gene, zinc is required for DNA binding specificity. When TFIIIA is bound to 5S RNA in the 7S particle, the protein does not bind to this 5' flanking region, an observation similar to that observed with binding to the 5S RNA gene. These results indicate TFIIIA is using similar nucleic acid binding domain(s) for interaction with the 5S gene, 5S RNA, and the 5' flanking region of its own gene. This upstream DNA region to which TFIIIA binds has been previously shown to contain a negative and a positive regulatory element for transcription of the TFIIIA gene (Scotto, K.W., Kaulen, H., and Roeder, R.G., 1989, Genes & Develop. 3, 651-662). The present results indicate TFIIIA binds to the negative control element located at -306 to -289 and possibly interacts/interferes with another transcription factor which binds to the positive control element extending from -271 to -253.
Animals↗
Effect of delayed fixation in the assessment of tumour cell proliferation.
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Cell Division↗
Use of reassortant viruses to map attenuating and temperature-sensitive mutations of the Rift Valley fever virus MP-12 vaccine.
A live-attenuated vaccine for Rift Valley fever virus (RVFV), MP-12, has been developed recently by undirected, serial mutagenesis of a RVFV strain (ZH548) isolated during the 1977 epidemic in Egypt. In the present study, the mutations responsible for attenuation of this virus have been examined by analysis of reassortant viruses generated between the vaccine strain and a wild RVFV strain isolated in Senegal. Reassortant viruses were generated efficiently in multiply infected Vero cells, and were readily isolated without application of selective pressures. The origin of the S and M genomic RNA segments in each cloned reassortant virus was determined with monoclonal antibodies capable of differentiating the nucleocapsid protein (S segment marker) or G1 glycoprotein (M segment marker) of the parental strains. The L segment of the vaccine strain was found to contain a temperature-sensitive (ts) mutation, and the origin of the L segment in most reassortants could be inferred by analysis of their ts phenotype. Analysis of the virulence properties of selected reassortant viruses in mice demonstrated that virulence characteristics were under polygenic control, and that at least one mutation capable of independently attenuating the virus existed on each genome segment. The L and M RNA segments were also found to contain ts mutations. These findings suggest that reversion to virulence is unlikely, and further indicate that genetic reassortment with wild-type viruses during a vaccination programme in endemic areas would also be expected to yield attenuated variants.
Animals↗
Effects of growth hormone injections on ovulation rate in ewes.
Coopworth ewes were either treated with 5 mg recombinant-derived bovine growth hormone per day for each day of the oestrous cycle or were untreated. Ovulation rates at the pre-treatment, post-treatment and a subsequent oestrus were determined by endoscopy. These were 1.34, 1.51, 1.38 for the treated ewes and 1.32, 1.43, 1.39 for the control ewes. The ovulation rate post-treatment was significantly higher than for the other two cycles in the treated ewes but it was not significantly different from the post-treatment value of the control ewes. Plasma concentrations of insulin-like growth factor-I (IGF-I) were elevated during treatment (90-130 nmol L-1) compared with concentrations of 25-50 nmol L-1 in the control ewes. No relationship was found between plasma IGF-I concentration and ovulation rate. Injection of ewes grazing ryegrass/white clover pasture with bovine growth hormone did not result in increased ovulation rate.
Animals↗
Effects of phenobarbital, dietary protein intake, and ewe liveweight on ovulation rate and concentrations of plasma FSH and hepatic microsomal enzymes.
Coopworth ewes were differentially fed from December 1985 to April 1986 to produce two liveweight classes: fat (55-60 kg) and thin (40-45 kg). The ewes were then fed on either high-protein (22%) or low-protein (12%) diets, with or without phenobarbital treatment for 10 days commencing on Day 7 of the oestrous cycle. Phenobarbital treatment caused an increase in ovulation rate that was most pronounced in thin ewes and those on the low-protein diet. Ewe liveweight produced an increase in ovulation rate, but increased dietary protein in the particular formulations used had no effect. Hepatic enzyme concentrations were increased by phenobarbital treatment and, to a lesser extent, by dietary protein intake and ewe liveweight. However, these metabolic changes and the increase in ovulation rate were not accompanied by interpretable changes in the plasma FSH concentrations.
Analysis of Variance↗
Generation and transmission of Rift Valley fever viral reassortants by the mosquito Culex pipiens.
Reassortant viruses containing heterologous S and M genomic RNA segments were obtained from both mosquito and vertebrate hosts that had been coinfected with Egyptian and Senegalese strains of Rift Valley fever (RVF) virus. The origin of the S and M RNA segments in each plaque-cloned virus was determined with monoclonal antibodies capable of differentiating the nucleocapsid protein (S segment marker) or the G1 glycoprotein (M segment marker) of the parental strains. In the mosquito Culex pipiens, reassortants were detected after sequential ingestion of parental viruses by interrupted feeding on two infected hamster hosts, after feeding on a single host that had been infected with both parental strains, and from individual mosquitoes inoculated intrathoracically with both parental strains. Reassortant viruses replicated efficiently in mosquitoes and were readily transmissible by bite to hamsters. Replication of a second infecting strain of RVF virus was, however, completely inhibited if that virus was inoculated into a mosquito greater than or equal to 48 h after the first viral strain. Genetic reassortment may provide a mechanism for increased heterogeneity, and thus affect the epidemiology and evolution of RVF virus.
Animals↗
Reproductive performance of Coopworth ewes following oral doses of zearalenone before and after mating.
The reproductive performance of Coopworth ewes after administration of zearalenone was determined in two trials. In Trial I, zearalenone was administered to groups of 33 ewes at rates of 0, 1.5, 3.0, 6.0, 12.0 and 24.0 mg/ewe/day for 10 days, starting on Day 7 of the oestrous cycle before mating. There was a linear decline (P less than 0.001) in ovulation rate with dose of zearalenone; also cycle length decreased and duration of oestrous increased with increasing dose levels. Reductions in the incidence of ovulation and in fertilization were seen only at doses of 12 and 24 mg. In Trial 2, groups of 50 ewes were given the same range of doses of zearalenone for 10 days, starting 5 days after mating to entire rams. There was no effect of zearalenone treatment after mating on pregnancy rate or embryonic loss. These results indicate that the effects of zearalenone, administered orally, on ewe reproduction, at the dose levels examined, were restricted to ewes exposed before mating. Intakes of zearalenone of 3 mg/ewe/day or more during this period would be reflected as depressed ovulation rates and lower lambing percentages.
Administration, Oral↗
Temporal relationship between the onset of oestrus, the preovulatory LH surge and ovulation in farmed fallow deer, Dama dama.
A study was conducted to determine the timing of ovulation relative to the onset of oestrus and the preovulatory LH surge in fallow deer. Mature fallow does were randomly allocated to two treatments (N = 10 per treatment) designed to synchronize oestrus on or about 17 May. Does assigned to Group 1 (prostaglandin-induced oestrus) each initially received single intravaginal CIDR [Controlled Internal Drug Release] devices for 13 days followed by an i.m. injection of 750 mg cloprostenol on Day 12 (15 May) of the subsequent luteal cycle. Does assigned to Group 2 (progesterone-induced oestrus) each received CIDR devices for 13 days, with withdrawal occurring on 15 May. All does were run with crayon-harnessed bucks (10:1 ratio) from the start of synchronization (18:00 h 15 May). Ten does (5 per group) were blood sampled via indwelling jugular cannulae every 2 h for 72 h from cloprostenol injection or CIDR device withdrawal and the plasma was analysed for concentrations of progesterone and LH by radioimmunoassay. Does within each treatment were randomly allocated to an ovarian examination time of 12, 16, 20 or 24 h after the onset of oestrus. Laparoscopy was repeated at 12-h intervals until ovulation was recorded. The ovaries of does failing to exhibit oestrus were examined 72 and 86 h after cloprostenol injection or CIDR device withdrawal. A total of 17 does were observed to exhibit oestrus at a mean (+/- s.e.m.) interval from treatment of 44.6 +/- 3.6 h for Group 1 (N = 9) and 34.1 +/- 2.5 h for Group 2 (N = 8).(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
In vitro synthesis of infectious venezuelan equine encephalitis virus RNA from a cDNA clone: analysis of a viable deletion mutant.
A molecular clone of Venezuelan equine encephalitis virus (VEE) was constructed from four cDNAs that were synthesized using the viral RNA genome as template. Together, these cDNAs are believed to represent all but the nine 5'-terminal nucleotides of the VEE genome sequence. A T7 promoter, followed by a single intervening G residue, and the exact 5'-terminus of VEE were added to the 5'-most clone using in vitro mutagenesis. Appropriate restriction fragments isolated from the cloned cDNAs were joined to form a candidate full-length VEE cDNA clone. RNA transcripts synthesized in vitro from the cDNA clone were able to initiate a productive infection in DEAE-dextran-treated chicken embryo fibroblasts (CEF). VEE antigens were demonstrated in RNA-transfected cells, and supernatants from transfected cultures contained infectious virus particles. The candidate full-length cDNA clone lacked 102 nucleotides of the VEE genome sequence. The deletion, which also was present in the genomes of progeny virions derived from the clone, did not appear to affect growth in cultured CEF, baby hamster kidney cells, or Vero cells. The site of the deletion was mapped to the 3'-end of the nsP3 gene by comparison to other alphavirus sequences. In this region, the VEE genome sequence includes two tandem 102-nucleotide repeats which can be arranged in a stable stem and loop structure. The sequence remaining in the deleted clone retains one copy of the duplicated sequence and, in addition, faithfully preserves a portion of the predicted stem.
Antigens, Viral↗
Development of sheep preimplantation embryos in media supplemented with glucose and acetate.
Two experiments were conducted to examine the effect of supplemental glucose (G; 1.5 mM) and/or acetate (A; 0.5 mM) on the development of early sheep embryos to blastocysts when cultured in vitro in glucose-free synthetic oviductal fluid (SOF)+sheep serum or bovine serum albumin (BSA). In Experiment 1, 2- to 4-cell, 8- to 16-cell and >16-cell embryos were cultured in SOF, SOF+G, SOF+A or SOF+G+A. All media were supplemented with 10% sheep serum. In addition, embryos were cultured in either microdrops under polysiloxane oil or in multiwell dishes. Overall, development to the blastocyst stage was 3%, 30% and 68% for 2- to 4-cell, 8- to 16-cell and >16-cell stages, respectively, suggesting that an 8-cell developmental block existed under our culture conditions. Glucose supplementation had little effect on embryo development, and no overall effect was observed from the addition of acetate. In Experiment 2, 8- to 16-cell embryos were cultured in SOF or SOF+G, both supplemented with BSA. Development to the blastocyst stage was 25% and 18%, respectively. The results show that the presence of glucose or acetate did little to enhance embryonic development in our incubation systems. Further work is required to evaluate fully the energy requirements for development of the early sheep embryo.
Journal Article↗
Short contact dithranol therapy: advantages of a stiff emulsifying ointment base.
In a single blind trial, 16 in-patients with psoriasis were treated with short contact dithranol in stiff Lassar's paste and in a stiff emulsifying ointment base of equivalent stiffness. The preparations were equally effective in clearing psoriasis and well tolerated. Perilesional treatment burns, reported with soft ointments, were not seen with the stiff emulsifying ointment preparation. Furthermore, unlike the paste, excess stiff emulsifying ointment can be removed by simply wiping with a moistened cloth, thus greatly facilitating home management of psoriasis.
Adolescent↗
Branchial cyst anomaly in a newborn.
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Branchioma↗
Blood lead and associated risk factors in Ontario children.
The purpose of this study was to determine blood levels in Ontario children and to identify those risk factors associated with higher blood lead levels. A random sample of 1315 children aged 7 and younger from urban, suburban and rural Ontario was selected. Blood lead concentration was determined in finger prick blood samples by graphite furnace atomic absorption spectrophotometry. Measurements of lead in air, tap water, soil, and gasoline were also established. Traffic pattern were determined in each area. A questionnaire was administered to a random sample of 800 families of the children tested to assess the presence of other risk factors. Urban children had higher geometric mean blood lead levels (12.02, S.D. = 4.4 micrograms/dl) than suburban children (9.95, S.D. = 3.5 micrograms/dl), and they, in turn, had higher blood lead levels than rural children (8.91, S.D. = 3.9 micrograms/dl). Each of these differences is statistically significant (p less than 0.001). Fifty four (4.3%) of all children were at or above the alert level of 20 micrograms/dl. The proportion above the alert level did not differ significantly between urban, suburban and rural children. Blood lead levels were slightly higher for males than females and for pre-schoolers aged 3 and 4, compared to school age children aged 5 and 6. The blood lead levels of these children were significantly lower than that of children surveyed near a point source of industrial emissions. Multivariate statistical modelling resulted in a set of characteristics which best explained the differences in children's blood lead levels.(ABSTRACT TRUNCATED AT 250 WORDS)
Age Factors↗
Electron microscopy study of twin behavior in GdBa2Cu3Ox and YBa2Cu3Ox.
Twins are ubiquitous in the perovskite superconductors. They form during cooling from high temperatures through the tetragonal-to-orthorhombic phase transformation. Their behavior has been studied by transmission electron microscopy using a liquid-nitrogen-cooled specimen holder. It is observed that extra twins sometimes form in coarse-twinned regions to give a "refined" twin structure; this is thought to be induced by thermal stresses from the electron beam. Prolonged electron irradiation (with little beam heating) results in transformation to tetragonal with a loss of the twin structure; this is probably due to disordering of the oxygen sublattice by knock-on displacement. The same transformations can be induced by deliberate electron beam heating. In both cases the twinned orthorhombic structure can be restored by re-ordering of the oxygen ions, in the first case by removing the beam and in the second case by allowing the specimen to cool.
Barium↗
Selection for accelerated penetration in cell culture coselects for attenuated mutants of Venezuelan equine encephalitis virus.
Previous studies with Sindbis virus (SB) suggested that a single point mutation in glycoprotein E2 (serine 114 to arginine 114) conferred three phenotypic alterations: attenuation in neonatal mice, accelerated penetration of cultured cells, and efficient neutralization by two E2-specific monoclonal antibodies (Davis, Fuller, Dougherty, Olmsted, and Johnston (1986) Proc. Natl. Acad. Sci. USA 83, 6771-6775). Moreover, selection for rapidly penetrating mutants of SB coselected for attenuation in vivo, indicating that a domain of SB E2 which influences penetration in culture overlaps an E2 domain which influences pathogenesis (Olmsted, Meyer, and Johnston (1986) Virology 148, 245-254). To test the possibility that overlapping penetration and pathogenesis domains exist in other alphaviruses, the virulent Trinidad donkey strain of Venezuelan equine encephalitis virus (TRD-VEE) was serially passed in baby hamster kidney (BHK) cells under a stringent selective pressure for accelerated penetration. Isolates were biologically cloned from the first through the fourth passages and were characterized as to penetration time course in BHK cells and virulence in adult mice following intraperitoneal inoculation. Twenty-two of the 27 isolates segregated into two major categories: slowly penetrating and virulent (like the TRD-VEE parent) and rapidly penetrating and avirulent. Mice which received the avirulent mutants were positive for anti-VEE neutralizing antibody and were refractory to challenge with TRD-VEE. Of the seven mouse avirulent mutants, two also were attenuated in hamsters, indicating the presence of at least two genetic loci at which mutations may influence both pathogenesis and penetration.
Animals↗
Rebounding exercise. Are the training effects sufficient for cardiorespiratory fitness?
Additional research is needed in order to document the effects of rebound training. Efforts should focus on the factors that are necessary for standardising the intensity of exercise such as step height and frequency. In addition, attention may be given to alternative methods of increasing exercise intensity while rebounding. One such method may be to increase the total muscle mass involved by adding the pumping of handheld weights to the rebounding exercise. Data from our laboratory (Bishop et al. 1986) has demonstrated that the addition of pumping 1-, 2- and 3-pound (0.45, 0.91 and 1.36 kg) handheld weights, at 2- and 3-foot (30 and 45 cm) heights, to rebounding exercise will increase the oxygen requirement from 26 to 60%. Assessing these effects in a training study would necessitate testing for adaptation in the upper extremities. This type of training highlights the need for activity specific tests. More specifically, additional research is needed to: 1. Determine the energy cost of activities other than jogging/bouncing that may be possible on a mini-trampoline, such as those described by White (1984). 2. Determine the training response of subjects in studies in which the controllable factors affecting intensity are standardised. 3. Examine the effects of longer periods of rebound training. Because rebounding exercise is novel to most subjects, it would appear that the length of training should allow subjects to maintain a reasonable frequency, intensity, and duration of exercise above that needed for familiarization with the new activity. 4. Determine if the prolonged use of other training aids (limb weights) with rebounding is feasible and effective in long term training.(ABSTRACT TRUNCATED AT 250 WORDS)
Cardiovascular Physiological Phenomena↗
Automatic wire twister.
This automatic wire twister used in surgery consists of a 6-inch needle holder attached to a twisting mechanism. The major advantage of this device is that it twists wires significantly more rapidly than the conventional manual techniques. Testing has found that the ultimate force required to disrupt the wires twisted by either the automatic wire twister or manual techniques did not differ significantly and was directly related to the number of twists. The automatic wire twister reduces the time needed for wire twisting without altering the security of the twisted wire.
Bone Wires↗