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Biomedical subjects

K Edwards

Publications and source records attributed to K Edwards.

At least 19 recordsLinked to original sources
PubMed1992

Construction and characterisation of a yeast artificial chromosome library containing two haploid Beta vulgaris L. genome equivalents.

We have constructed a yeast artificial chromosome (YAC) library using high-molecular-weight DNA prepared from agarose-embedded protoplasts of a sugar beet (Beta vulgaris L.) cell suspension line, Ar+. This library contains 15,000 clones with an average insert size of 140 kb. Based on a sugar beet haploid genome size of 1.1 x 10(3) Mb it should represent approximately two haploid genome equivalents. The library is organised as an ordered array in duplicate microtitre plates. High-density filters, each containing 864 YAC clones, have been screened in colony hybridisation experiments. In this way, sugar beet YAC clones have been identified containing chloroplast DNA, mitochondrial DNA and two satellite DNAs. Ten pools of DNA from 1500 individual YAC clones have also been prepared for rapid PCR screening of the library. Using this approach, in combination with colony hybridisation, we have been able to isolate sugar beet YAC clones containing a transcribed low-copy-number gene.

Base Sequence↗
PubMed1992

Antibody response to Bordetella pertussis antigens after immunization with American and Canadian whole-cell vaccines.

Because of apparent differences in the incidence and epidemiology of pertussis in the United States and Canada, we measured the antibody response to four Bordetella pertussis antigens and to a whole-bacteria preparation in children immunized with American and Canadian whole-cell pertussis vaccines. All infants received combined pertussis, tetanus, and diphtheria vaccines from one of two American manufacturers or a single Canadian manufacturer. The Canadian children received either oral poliomyelitis vaccine, inactivated poliomyelitis vaccine as a separate injection, or a product that combined inactivated poliomyelitis vaccine with diphtheria, tetanus, and pertussis components. The Canadian trivalent diphtheria, tetanus, and pertussis vaccine given with oral poliovirus vaccine induced lower anti-pertussis toxin antibody titers than did the American vaccines (p < or = to 0.05) but higher antifimbriae and anti-69-kilodalton outer-membrane protein (pertactin) antibody titers (p < or = to 0.02). Canadian children immunized with inactivated poliomyelitis vaccine either as a separate injection or as a combined diphtheria, tetanus, and pertussis vaccine had consistently lower pertussis antibody titers than did those who received oral poliomyelitis vaccine (p < or = 0.001). We conclude that there is a wide range of antibody responses to B. pertussis antigens after immunization with various whole-cell pertussis vaccines, and that these responses may be influenced by concurrent administration of other vaccines.

Antibodies, Bacterial↗
PubMed1992

Results of laboratory surveillance of very low birth weight infants treated with a synthetic surfactant.

During two randomized, controlled trials comparing single prophylactic doses of air placebo and a synthetic surfactant, Exosurf Neonatal, many routine laboratory measurements were made in small premature infants during the first week of life. Values for serum electrolytes, urea, creatinine, phospholipid, cholesterol, glucose, calcium, bilirubin, and liver enzymes, as well as for hemoglobin, leukocyte and platelet counts, and urinalysis, did not differ between the placebo- and surfactant-treated infants. There was no evidence that prophylactic administration of this synthetic surfactant causes alterations in standard laboratory tests in small premature infants.

Blood↗
PubMed1992

Retrospective search for bleeding diathesis among premature newborn infants with pulmonary hemorrhage after synthetic surfactant treatment. The American Exosurf Neonatal Study Group I, and the Canadian Exosurf Neonatal Study Group.

In an across study analysis of five multicenter, placebo-controlled trials of the synthetic surfactant, Exosurf Neonatal, involving infants with birth weights 700 gm or greater the incidence of clinical pulmonary hemorrhage was 1.9% in treated infants and 1.0% in control infants. To determine whether this apparent increase in pulmonary hemorrhage was the result of a bleeding diathesis, we retrospectively reviewed charts for 39 of 41 infants with clinical pulmonary hemorrhage. The incidence of nonpulmonary bleeding was the same in control- and surfactant-treated infants. Platelet counts, hematocrit values, and the number of transfusions with platelets or red blood cells did not differ between the two groups. There was no evidence that surfactant treatment was specifically associated with a generalized bleeding diathesis.

Double-Blind Method↗
PubMed1992

The rise of private practice: a growing disquiet with public services?

A survey of 325 national patients attending six private clinics in Port Moresby was carried out to determine the characteristics of those using private medical services. Most patients were employed in professional or clerical occupations. A sizeable proportion of private patients were from low and moderate income categories and over 40% of those interviewed said that they had to borrow the money to pay for the consultation. Education level was positively associated with both attending a private practitioner as first choice of treatment and enrollment in a medical insurance scheme. 15% of patients were medically insured, and they were more likely to choose a private practitioner as first treatment choice. The most common reason given for choosing private sector health care was that it was quicker, but a notable proportion, particularly amongst those who had previously attended government health services for the same complaint, thought that private clinics had better doctors or gave better medicine. The findings are discussed and contrasted with those from other developing countries. Conclusions are drawn regarding the significance of these findings both in relation to the upgrading of the public health services and the regulation and monitoring of private health services.

Adolescent↗
PubMed1992

Social evaluation of behaviors comprising three social skills and a comparison of the performance of people with and without mental retardation.

We evaluated whether behaviors commonly taught to persons with mental retardation as part of three important social skills (following instructions, accepting criticism, and negotiating to resolve conflicts) were responded to favorably by other people. People with mental retardation who lived in the community and other people from the community participated in videotaped role plays involving each of the social skills. The performances of participants were scored according to behavioral checklists. Participants with mental retardation scored as well as other participants on following instructions and accepting criticism but lower on negotiating. Community members were asked to evaluate how well the participants did in the videotaped role-play situations. There were high positive correlations between the scores derived from the behavioral checklists and the evaluations of community members for both groups of participants.

Adolescent↗
PubMed1990

Gowning on a postpartum ward fails to decrease colonization in the newborn infant.

We conducted a randomized study to evaluate the effect of gowning by visitors and hospital personnel on a postpartum ward on nose and umbilical colonization and disease in healthy newborn infants. Cultures were obtained in infants assigned to the gowning and nongowning groups within 6 hours of birth from the anterior part of the nares and the base of the umbilicus and at the time of discharge from the nursery. There were 102 infants in the gowning group and 100 infants in the nongowning group. No significant differences were noted between the two groups with respect to sex, length of stay, mode of delivery, weight, or status of nursery admission culture results. The use of gowns on a postpartum ward failed to decrease nose or umbilical colonization when compared with infants in the nongowning group. Seventy (68.6%) of 102 infants in the gowning group and 65 (65%) of 100 infants in the nongowning group had negative umbilical cord cultures on admission to the nursery that became positive at discharge. On follow-up, no differences were noted between the two groups with respect to their health. Only one infant in each group had an infection develop in the first 4 weeks of life. We conclude that the routine use of cover gowns on postpartum units in healthy full-term infants is ineffective and costly. It may discourage health care providers from examining patients and providing care.

Cross Infection↗
PubMed1990

ADP-ribosylation of cerebrocortical synaptosomal proteins by cholera, pertussis and botulinum toxins.

Certain microbial toxins ADP-ribosylate G proteins that may be related to those postulated to participate in secretion, whilst botulinum neurotoxins, produced by Clostridium botulinum, block Ca2(+)-dependent neurotransmitter release. Thus, botulinum, pertussis and cholera toxins were examined for ADP-ribosyl transferase activity using isolated nerve terminals. Although type D botulinum, cholera and pertussis toxins exhibited such enzymic activity, this was not detectable with types A or B botulinum neurotoxins or their individual chains, in any synaptosomal fraction. Botulinum type D and pertussis toxins ADP-ribosylated proteins with mol. wt approximately 24,000 and 42,000 respectively, whereas cholera toxin modified several proteins including a 51,000/47,000 mol. wt doublet. Pre-incubation of synaptosomes with type A, B or D toxins did not inhibit type D-induced labelling in the corresponding lysate. Similar pre-incubations with cholera or pertussis toxins reduced ADP-ribosylation of their substrates. Hence, under conditions in which these botulinum toxins were shown to block Ca2(+)-dependent transmitter release no ADP-ribosylated substrate was produced in the intact nerve terminals. Moreover, direct correlation was not found between the concentration dependencies of type D toxin for protein modification and inhibition of [3H]noradrenaline release from synaptosomes. These collective findings implicate C3, a non-neurotoxic contaminant of type D, in the enzymic action. The substrate for type D toxin was found in the cytosolic fraction and to a lesser extent in synaptic membranes, the reverse of the situation for pertussis toxin. A combination of the membranes and cytosol was required for maximal labelling of the 51,000/47,000 doublet by cholera toxin. Purified synaptic vesicles contained proteins labelled by type D and pertussis toxins but lacked major cholera toxin substrates. Future research will determine the possible involvement of these toxin-susceptible vesicular proteins in transmitter release.

Adenosine Diphosphate Ribose↗
PubMed1990

Health insurance coverage of Minnesota farm families.

This study of 1,482 farm families assesses the extent and cost of health insurance coverage among Minnesota farm families and finds that these families are buying less insurance coverage than urban families, while paying a higher proportion of their income for these premiums. More than three-fourths of the farm families surveyed buy their health insurance plan themselves and pay for it out of pocket. Their plans, on average, are slightly less expensive than employer-provided plans in urban areas, but they provide much less coverage and have more copayments and deductibles. Unlike their urban counterparts, who often choose health plans for convenience of location or freedom to choose physicians, farmers generally choose plans on the basis of costs and services provided. About 7 percent of farm families are without insurance, and many others are underinsured because they cannot afford to purchase an adequate plan.

Cost Control↗
PubMed1989

Tissue- and cell-specific activity of a phenylalanine ammonia-lyase promoter in transgenic plants.

Phenylalanine ammonia-lyase (PAL) catalyses the first step in the biosynthesis of phenylpropanoids, which form a wide variety of plant secondary products. The transcription of PAL is regulated in response to various factors that induce the accumulation of flavonoids, lignin and compounds thought to be involved in plant defence reactions. The 5' upstream sequence of a PAL gene from Phaseolus vulgaris was fused to the coding region of the reporter gene encoding beta-glucuronidase (GUS), and transformed into potato and tobacco plants. Histochemical analysis of GUS expression showed that the PAL promoter was active in specific cell types that accumulated phenylpropanoid derivatives in response to mechanical wounding, and also during normal development of the xylem and flower. In xylem that had undergone secondary thickening, GUS activity occurred in rays of cells thought to be the xylem parenchyma. It was postulated that PAL activity in these cells could provide intermediates for lignin synthesis in xylem vessels that had terminally differentiated.

Ammonia-Lyases↗
PubMed1987

Priming and induction of Haemophilus influenzae type b capsular antibodies in early infancy by Dpo20, an oligosaccharide-protein conjugate vaccine.

A conjugate vaccine (Dpo20) was made by direct coupling of diphtheria toxoid and oligosaccharides obtained by periodate oxidation of Haemophilus influenzae type b capsular polysaccharide. This approach gave a higher multiplicity of saccharides per protein and greater immunogenicity in infancy than our previously studied conjugates. Thirty-three healthy infants received three sequential injections, and no serious side effects were observed. When Dpo20 was given with diphtheria-tetanus-pertussis vaccine at ages 2, 4, and 6 months, the geometric mean titer of anticapsular antibody rose to 5.9 micrograms/ml at age 7 months. Dpo20 given at 3, 5, and 7 months raised the mean to 3.2 micrograms/ml at 7 months (after two injections) and 15.4 micrograms/ml at 10 months. The antibodies included IgG and were bactericidal in vitro. Thus, antibody activities potentially protective against invasive H. influenzae b infections were induced in the most susceptible age range. The infants also became primed for mature-for-age responses to (unconjugated) polysaccharide vaccine given as a booster at age 12 months.

Age Factors↗