Parasites of pet animals: progress and new hazards.
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Animal Diseases↗
Biomedical subjects
M M Taylor
Publications and source records attributed to M M Taylor.
A different function for a critical tryptophan in c-Raf and Hck.
The similarity of the catalytic domains of Raf and Src family members suggests that functions of homologous residues may be similar in both kinase families. A tryptophan residue, W260, in the WEI region of the Src family kinase Hck has an important role in regulating ATP binding. We tested the hypothesis that the tryptophan, W342, in the WEI region of c-Raf may have a similar role to the W260 of Hck. Mutation of W260 to A in Hck activates kinase activity, but we found that mutation of W342 to A in c-Raf inactivates the kinase activity. Mutating W342 to aspartate (D), lysine (K) or histidine (H) also inactivated c-Raf whether assayed as a purified immunoprecipitate or when recruited to the plasma membrane. A constitutively active c-Raf can be generated by mutating two regulatory tyrosines to aspartate. When placed into this active c-Raf mutant, mutation of W342 to D, K or H enabled phosphorylation and activation of the c-Raf substrate MEK at the plasma membrane but not in an immunoprecipitation assay. We conclude that (1) Tryptophan has a different role in the WEI regions of c-Raf and Hck, (2) W342 is not directly involved in MEK binding as both positive and negative residues at 342 are permissive for MEK activation at the membrane in a constitutively active c-Raf mutant, (3) Factors at the membrane are capable of potentiating activation of c-Raf containing mutated W342 in a hyperactivated c-Raf, but not in a wild type c-Raf and (4) There is a stringent structural requirement for W at residue 342 in c-Raf.
Amino Acid Sequence↗
Reasons for tooth extraction in Scotland.
OBJECTIVES: A 1984 study investigated the reasons underlying the extraction of teeth in Scotland. The survey described in this paper, used a similar methodology and aimed to determine the reasons for the extraction of permanent teeth by general dental practitioners and investigate changes in the influences on tooth extraction over a 10 year period. METHODS: During a 1 week period in November 1994, 139 general dental practitioners working throughout Scotland, recorded the reasons for all permanent tooth extractions. RESULTS: A total of 917 permanent teeth were extracted from 613 patients, the reason for extraction being stated as dental caries (51%), periodontal disease (21%), orthodontics (11%) and failed endodontics (4%). Trauma, pericoronitis and other reasons accounted for 5.5% of extractions whilst, in 7.5% of cases, patients requested extraction in preference to other treatments. The proportion of extractions attributed to periodontal disease increased from age 31-60 years, but declined thereafter. CONCLUSIONS: Comparing the results with those obtained in the 1984 study, whilst the mean number of teeth extracted by each practitioner had reduced, the overall relative contribution of different reasons for extraction was similar.
Adolescent↗
Generation of mutant murine cytomegalovirus strains from overlapping cosmid and plasmid clones.
We have developed a cosmid and plasmid system to generate mutant strains of murine cytomegalovirus (MCMV). The system is based on a series of seven overlapping cosmid clones that regenerate MCMV when cotransfected into mouse cells. The unaltered cosmids produce MCMV that is indistinguishable from wild-type MCMV based on restriction enzyme digest patterns of virus DNA and growth rates both in vitro and in vivo. Analysis of viral DNA from plaque-purified recombinant isolates taken from in vitro and in vivo stocks indicated that regeneration did not introduce novel mutations in the recombinant viral genomes. Isolation of specific genes and subsequent generation of specific mutant MCMVs was accomplished by replacement of cosmids with overlapping plasmid subclones. A new vector, PmeSUB, featuring a multiple cloning site and a stringent origin of replication, was constructed to make large subclones for use with smaller subclones containing the gene of interest. The utility of this system was demonstrated by the generation of two different mutant MCMVs from different combinations of overlapping plasmid subclones of one cosmid. The advantages of this system are that (i) target genes are maintained as small clones making them amenable to standard in vitro mutagenesis manipulations and that (ii) no reporter or selection genes are necessary to identify mutants.
Animals↗
The provision of dental and oral health advice by community pharmacists.
A common theme of recently published strategies for improving oral health has been the need to involve healthcare professionals so as to influence a wider section of the population, many of whom do not routinely attend a dentist. The purpose of this paper is to review changes that have affected pharmacy practice in the community, to identify opportunities and barriers to the provision of dental and oral health advice in that setting, and to propose increased collaboration between the dental team and pharmacy staff.
Community Pharmacy Services↗
Assessment of the MDA and MDMA optical isomers in a stimulant-hallucinogen discrimination.
The phenylisopropylamine derivatives 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyamphetamine (MDA) have been compared to both psychostimulants and hallucinogens in drug discrimination investigations. The stereoisomers of these compounds, in particular those of MDA, appear to produce differential effects. Previous studies have demonstrated that animals trained to discriminate amphetamine from vehicle generalize to the S(+)-isomers but not the R(-)-isomers of MDA and MDMA while animals trained to discriminate LSD from saline generalize to R(-)-MDA and neither isomer of MDMA. However, animals trained to discriminate mescaline from vehicle generalize to both stereoisomers of these phenylisopropylamine derivatives. The present study consisted of two experiments in which a three-choice drug discrimination procedure was employed to compare the stereoisomers of MDA and MDMA to both amphetamine and either mescaline (experiment one) or LSD (experiment two). Sixteen male Sprague-Dawley rats were trained to discriminate S(+)-amphetamine (1.0 mg/kg) and mescaline (12.5 mg/kg) and eight rats were trained to discriminate S(+)-amphetamine (1.0 mg/kg) and LSD (0.08 mg/kg) from saline in three-choice, food reinforced drug discrimination procedures. Substitution tests were administered with the isomers of MDA and MDMA. In the second experiment, substitution tests were also administered with lower doses of each training compound and with the stimulant cocaine and the hallucinogen 2,5-dimethoxy-4-methylphenylisopropylamine (DOM). In both experiments, all of the isomers produced very few responses on the S(+)-amphetamine lever. In the first experiment, R(-)-MDA and R(-)-MDMA produced nearly complete substitution for mescaline. The results of the second experiment revealed partial substitution for LSD with both isomers of MDMA and S(+)-MDA, and nearly complete substitution with R(-)MDA for LSD. The present findings do not support previous reports that S(+)-MDMA and S(+)-MDMA substitute for S(+)-amphetamine. The three-lever drug discrimination procedure may provide a more sensitive behavioral assay in which to examine the discriminative stimulus effects of drugs with compound stimulus properties.
DOM 2,5-Dimethoxy-4-Methylamphetamine↗
Posterior cervical dura is much thicker than the anterior cervical dura.
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Adult↗
Intraocular bacterial contamination during cataract surgery in dogs.
Prevalence of intraoperative contamination of the eyelids, conjunctival sac, and aqueous humor of 50 canine eyes that underwent elective cataract surgery was determined, and the short-term outcomes for contaminated and noncontaminated eyes were compared by scoring media clarity, pupil size and shape, and behavioral evidence of vision during the initial 30-day postoperative period. Results of bacteriologic culture of anterior chamber samples were positive for 12 of the 50 (24%) eyes, but anterior chamber contamination was unrelated to results of bacteriologic culture of eyelids or conjunctival sac swab samples. Eyes undergoing phacoemulsification were less likely to be contaminated than were eyes undergoing intra- or extracapsular extraction. Eyes undergoing intra- or extracapsular extraction and eyes with anterior chamber contamination had a greater likelihood of developing glaucoma postoperatively. We did not detect an association between intraocular contamination and the surgeon performing the operation, the need for postoperative administration of tissue plasminogen activator, or the presence or absence of diabetes mellitus. Also, we did not detect any differences in outcome between eyes with and without intraocular contamination. Despite intraoperative bacterial contamination of the anterior chamber, bacterial endophthalmitis did not develop in any of the eyes.
Animals↗
Simple assay of calcium dependency for virulent plasmid-bearing clones of Yersinia enterocolitica.
A simplified procedure to detect the calcium dependency of virulent plasmid-bearing strains of Yersinia enterocolitica was developed. A low-calcium, agarose-based medium of brain heat infusion with added magnesium effectively differentiated plasmid-bearing and plasmidless isolates. Further, the expression of calcium dependency in plasmid-bearing strains of Y. enterocolitica as measured by the average colony diameter was proportional to the calcium concentration of the assay.
Calcium↗
Unsuspected damage to lumbar zygapophyseal (facet) joints after motor-vehicle accidents.
Three zygapophyseal joints from each of 31 lumbar spines of subjects who died of injuries (mostly as a result of motor-vehicle accidents) were sectioned for low-power histological study. Bony injuries, in the form of fractures of the superior articular process or infractions of the subchondral bone plate, were found in 11 of the 31 subjects and soft-tissue injuries to the capsule or articular cartilage were found in one-or-more joints in 24 of the 31 subjects, with capsular and articular-cartilage damage in 77% of cases. Healed injuries of a similar type, which were unrelated to the cause of death, were found in other lumbar spines. None of these lesions was diagnosed by standard radiological examination of the spine post mortem. It is suggested that, in survivors, bony and soft-tissue injuries to zygapophyseal joints may result in considerable pain and dysfunction and may predispose to early arthritis.
Accidents, Traffic↗
Generalized equations for predicting functional capacity from treadmill performance.
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Cardiovascular Diseases↗
Gastric stapling for morbid obesity: gastrointestinal response in a rat model.
The adaptive response of the gastrointestinal tract to gastric stapling was studied in a Zucker (fafa) genetically obese rat model. The effects of gastric stapling in rats with a Roux-en-Y gastrojejunostomy were compared to Roux-en-Y and intact controls. Rats (225 to 275 g) were divided into three groups: group I (GI), Roux-en-Y, stapled, ad libitum fed; group II, Roux-en-Y, unstapled; and group III, intact (laparotomy only). Groups II and III were further subdivided into group IIA (GIIA) and group IIIA (GIIIA), pair-fed to GI; and group IIB (GIIB) and Group IIIB (GIIIB), fed ad libitum. All rats were fed a diet of liquid rat formula and rat food (50:50 cal ratio). After 2 wk rats were killed and the liver, pancreas, and stomach removed, weighed, and tissue taken for histology. The intestine was divided into three segments corresponding to the excluded segment (1, duodenum), transposed segment (2, jejunum), and ileal segment (3), with tissue taken for histology. Liver lipid, pancreatic amylase, serum amylase and gastrin, and intestinal mucosal protein and DNA were measured. Weight gain, g/14 days, was: GI, 24.1 +/- 7.8; GIIA, 17.0 +/- 2.0; GIIB, 42.6 +/- 4.8; GIIIA, 17.6 +/- 4.7; GIIIB, 54.6 +/- 8.9. All rats were in positive N balance. Liver weight and lipid were similar in all groups. Pancreatic mass was significantly increased in all Roux-en-Y animals, while amylase activity per g tissue was significantly less than in intact animals. Stapled rats had atrophy of the glandular portion of the stomach, decreased stomach mucosal weight, and lower serum gastrin concentration compared with all other rats (p less than 0.01). In stapled rats, segment weight and mucosal weight were lower in the excluded segment, and higher in the transposed segment, compared to all other rats. Tissue pathology was found only in stapled rats: gastric atrophy, focal fibrosis of gastric wall, peritonitis, minimal to mild multifocal hepatitis, and mild periductal fibrosis of the pancreas. There are significant early adaptive and pathological changes after gastric stapling in the rat.
Adaptation, Physiological↗
PEST reduces bias in forced choice psychophysics.
Observers performed several different detection tasks using both the PEST adaptive psychophysical procedure and a fixed-level (method of constant stimuli) psychophysical procedure. In two experiments, PEST runs targeted at P (C) = 0.80 were immediately followed by fixed-level detection runs presented at the difficulty level resulting from the PEST run. The fixed-level runs yielded P (C) about 0.75. During the fixed-level runs, the probability of a correct response was greater when the preceding response was correct than when it was wrong. Observers, even highly trained ones, perform in a nonstationary manner. The sequential dependency data can be used to determine a lower bound for the observer's "true" capability when performing optimally; this lower bound is close to the PEST target, and well above the forced choice P (C). The observer's "true" capability is the measure used by most theories of detection performance. A further experiment compared psychometric functions obtained from a set of PEST runs using different targets with those obtained from blocks of fixed-level trials at different levels. PEST results were more stable across observers, performance at all but the highest signal levels was better with PEST, and the PEST psychometric functions had shallower slopes. We hypothesize that PEST permits the observer to keep track of what he is trying to detect, whereas in the fixed-level method performance is disrupted by memory failure. Some recently suggested "more virulent" versions of PEST may be subject to biases similar to those of the fixed-level procedures.(ABSTRACT TRUNCATED AT 250 WORDS)
Auditory Perception↗
Retrolental fibroplasia: further clinical evidence and ultrastructural support for efficacy of vitamin E in the preterm infant.
To further evaluate the efficacy of oral vitamin E in preventing the development of severe retrolental fibroplasia (RLF) in very low-birth-weight infants, 100 infants treated with 100 mg/kg/d of vitamin E (dl-alpha-tocopheryl acetate) were compared with 75 infants treated with 5 mg/kg/d of vitamin E (dl-alpha-tocopherol) in the same nursery during the previous year. All 175 infants weighed less than or equal to 1,500 g at birth and required supplemental oxygen. A total of 120 infants (69 treatment; 51 control) survived greater than or equal to 10 weeks. Multivariate analysis of the control population identified five risk factors (P less than or equal to .10): gestational age, level and duration of oxygen administration, intraventricular hemorrhage, sepsis, and birth weight. When multivariate analysis was applied to both control and treatment groups, the severity of RLF was found to be significantly reduced in infants given the treatment dose of vitamin E (P = .003). Ultrastructural analyses of 58 pairs of whole-eye donations from high-risk infants surviving less than 10 weeks suggest that the initial morphologic event is gap junction increases between the plasma membranes of adjacent spindle cells of the van-guard retina. Such extensively gap junction-linked spindle cells are apparently removed from the vasoformative process as early as 4 days of life, forming a barrier to further normal vascular development and triggering retinal and vitreal neovascularizations approximately 8 weeks later. These events are maximally suppressed by elevated plasma vitamin E levels in infants greater than or equal to 27 weeks gestational age.
Cell Membrane↗
Microscopic examination of the intracellular fate of infectious herpes simplex virus DNA.
The intracellular fate of 3H-labeled exogenous herpes simplex virus type 2 DNA following the exposure of recipient cells to selected DNA facilitators and the ultrastructural changes which ensued in transfected cultures were examined. In most cases, electron microscopic radioautography demonstrated that exogenous DNA reached the nucleus within 1 h postinoculation. At later time periods, enlargement of nuclei and margination of chromatin were noted. Cells treated with polyornithine differed significantly from those treated with other facilitators in that large cytoplasmic accumulations of labeled material associated with electron-dense, membrane-bound bodies persisted after 1 h postinoculation. In contrast, labeled DNA released by intact virions was detected in the nucleus as early as 20 min postinfection (p.i.), and progeny virus was evident by 8 h p.i. These results suggest that the efficiency of each facilitator is related to the rapidity with which exogenous DNA penetrates the recipient cell, traverses the cytoplasm, and the amount of DNA which is finally associated with the nuclear compartment.
Alkaloids↗
Use of therapeutic play in the ambulatory pediatric hematology clinic.
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Adolescent↗
35S-Sulfide incorporation during alkaline treatment of keratin and its relation to lanthionine formation.
Cattle hair exposed to solutions of 35S-sulfide ions at pH 12.5, hydrolyzed with acid, and analyzed for amino acids with simultaneous measurement of the radioactivity of the eluate from the analytical column showed 87 percent of the radioactivity incorporated in the hair in three amino acids: cysteic acid, lanthionine, and cystine. This and other evidence presented lend further support to the intermediacy of dehydroalanyl residues formed by a beta-elimination reaction in the conversion of cystinyl residues to lanthionyl residues in proteins. The presence of radioactively labelled cystine in the hydrolyzate indicates that the dehydroalanyl residues are also capable of reforming cystinyl residues under these same conditions through a series of reversible reactions.
Alanine↗