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Biomedical subjects

R D Edwards

Publications and source records attributed to R D Edwards.

36 records · Page 2Linked to original sources
PubMed1992

Case report: superior vena cava obstruction complicated by central venous thrombosis--treatment with thrombolysis and Gianturco-Z stents.

Expandable wire stents can provide effective palliation of superior vena cava obstruction (SVCO). We describe a case of SVCO unresponsive to radiotherapy and chemotherapy, which was complicated by extensive central venous thrombosis. Successful thrombolysis occurred with low-dose streptokinase allowing subsequent stent placement.

Brachiocephalic Veins↗
PubMed1992

Case report: pancreatic mediastinal pseudocyst--an unusual cause of palpitations.

We describe a case of pancreatic mediastinal pseudocyst which presented atypically with palpitations due to marked cardiac compression. Computed tomography (CT) showed a large abdominal pseudocyst extending through the diaphragm into the posterior mediastinum. Surgical drainage produced rapid symptomatic relief and the pseudocyst resolved completely within 2 months.

Arrhythmias, Cardiac↗
PubMed1986

Studies on the purification of the leucocidin of Fusobacterium necrophorum and its neutralization by specific antisera.

Leucocidin from several strains of Fusobacterium necrophorum was partially purified by gel filtration on Fractogel HW55 (F), the majority of the activity being present in the 50 ml of filtrate collected after 1.1 void volumes had passed through the column (termed Fraction 1, or #1). The material also contained lipopolysaccharide in 12.5% SDS-PAGE gels run under reducing conditions, but the protein did not migrate into 7.5% PAGE gels run under non-reducing conditions. Rabbit and bovine antisera to the leucocidin possessed antibodies against antigens in concentrated, washed culture supernates from toxigenic F. necrophorum and neutralized the leucocidal activity of such supernates. Absorption of the antisera with homologous, washed F. necrophorum cells reduced ELISA antibody titres by greater than 50%, but decreased neutralization titres by 15%. Absorbed rabbit IgG anti-#1 precipitated a single rocket in crossed immunoelectrophoresis and identified two proteins, of molecular weights (M.W.) 14 000 and 13 000, and 1 protein of M.W. 13 500 in immunoblots from toxigenic and non-toxigenic strains, respectively. An additional protein of M.E. 103 000 was present after SDS-PAGE separation of supernates from toxigenic but not non-toxigenic F. necrophorum and was not present in whole cell components. It was considered that the leucocidin may be present in a dimeric form in culture supernates from toxigenic strains. Antisera to leucocidins from several strains of F. necrophorum exhibited variable neutralization titres against leucocidins from heterologous bacteria.

Agglutination Tests↗
PubMed1976

Studies on immune responses to parasite antigens in mice. I. Ascaris suum larvae numbers and antiphosphorylcholine responses in infected mice of various strains and in hypothymic nu/nu mice.

In terms of day 7 lung larvae numbers, mice vary markedly in their suscepibility to a first infection with the nematode worms, Ascaris suum, and the highly susceptible strain, C57Bl, is resistant to second infection. Time course studies suggested that the period of residence in the liver or migration to, or into, the lungs are stages of the life cycle in which natural or acquired resistance of the host is expressed. The traits, susceptibility and resistance to first infection, were under polygenic control and no linkage of susceptibility to the major histocompatibility complex of C57Bl mice (H-2b) was observed. Acquired resistance (to second infection) has not been dissected because of our inability to show adoptive transfer of resistance to naive recipeints. Studies in hypothymic BALB/c. nu/nu mice indicate that natural resistance (to first infection) is not affected by a lack of T cells. The T cell dependence of acquired resistance in C57Bl mice remains in doubt although in the relatively resistant strain BALB/c, hypothymic nu/nu mice after second infection contain as many larvae in their lungs and liver as are present after first infection. An eosinophilia is observed in infected intact mice but not in infected T cell-deficient mice. Partially T cell-dependent serum antibodies and plaque-forming cells to phosphorylcholine (PC) were present in mice infected with A. suum but no evidence was obtained that this anti-PC antibody response was in any way protective for the host. The cell membrane-acitive properties of PC and related molecules suggest that PC-containing parasite antigens may be tolerogens for certain of the B cells with specificity for parasite antigens. A state of partial tolerance involving high affinity antibody production may be one means whereby parasites survive in natural or unnatural hosts.

Animals↗
PubMed1976

Studies on immune responses to parasite antigens in mice. III. Nippostrongylus brasiliensis infections in hypothymic nu/nu mice.

Normal mice of several strains reject the nematode worm Nippostronglyus brasiliensis from the intestine within 14 days (and most often within 10 days) of injection of high numbers of infective third stage larvae (L3). Previously-infected mice are markedly resistant to a second infection. Hypothymic, nu/nu ('nude') mice continue to harbor worms long after intact mice have rejected the worm burden and an inoculum of T cells at the time of, or several days after L3 injection, leads to worm elimination within 14 days in nu/nu mice. As yet no evidence is available to indicate whether or not T cells with specificity for parasite antigens are required in a reconstitutive inoculum in nu/nu mice. Pretreatment of normal mice with cyclophosphamide, at doses reported to lead to temporary B cell hypofunction, does not result in delayed rejection of worms but the participation of B cell products (antibodies) cannot be discounted on the basis of this result. The nu/nu mouse - N. brasiliensis system will be useful in the search for, and characterization of, parasite antigens which gain access to the lymphoid organs and circulation of parasitized mice and in the analysis of T cell subtypes (both functional and surface Thy and Ly alloantigenic subtypes) involved in worm elimination.

Ancylostomatoidea↗
PubMedDate not supplied

Graft distortion after endovascular repair of abdominal aortic aneurysm: association with sac morphology and mid-term complications.

PURPOSE: To investigate the incidence, significance, and mechanism of stent-graft distortion after endovascular repair (EVR) of abdominal aortic aneurysm. METHODS: EVR of abdominal aortic aneurysm was performed in 51 cases (49 modular, bifurcated; 2 tube). Thirty-two patients were followed for 6 or more months and had equivalent baseline and follow-up images which could be used to determine changes in graft configuration. Sac dimensions were measured using computed tomographic (CT) images and graft-related complications were recorded. RESULTS: Amongst 32 patients evaluated on follow-up, there was graft distortion in 24. Distorted grafts were significantly (p = 0.002) associated with sac diameter reduction (mean 5 mm) and sac length reduction (mean 8.1 mm). All graft-related complications occurred in the limbs of eight distorted grafts, with a mean reduction of sac length in this group of 7.8 mm on reformatted CT images. CONCLUSION: There was a highly significant association between graft distortion and limb complications, and reduced sac dimensions.

Aged↗
PubMedDate not supplied

Patient tolerance of cervical esophageal metallic stents.

PURPOSE: To demonstrate that proximal esophageal stenoses and tracheoesophageal fistulas can be adequately palliated with use of metallic stents without significant foreign-body sensation. MATERIALS AND METHODS: Between June 1994 and March 1999, 22 patients with lesions within 3 cm of the cricopharyngeus were treated by placement of metallic stents. The series was reviewed retrospectively. Twenty patients had surgically unresectable malignant lesions, two patients had benign disease. Ten patients had associated tracheoesophageal fistulas. In all, the upper limit of the stent was between C5 vertebral body inferior endplate and the T2 vertebral body superior endplate. The case-notes were reviewed until patient death (range, 6-198 days), or to date in the two surviving patients with benign disease. RESULTS: Immediate technical success was 93% (27 of 29). Dysphagia scores improved from a median of 3 to 2 after stent placement. Eighteen of 22 (82%) patients reported no foreign-body sensation. There have been no cases of proximal migration, periprocedural perforation, or deaths. The two patients with benign disease experienced significant complications. CONCLUSION: Lesions in proximity to the cricopharyngeus can be successfully palliated without significant foreign-body sensation in the majority of patients with use of metallic stents. The authors urge caution in placing stents in patients with benign disease.

Adult↗
PubMedDate not supplied

The EL sampler: a press sampler for the quantitative estimation of dermal exposure to pesticides in housedust.

Indirect sampling techniques to estimate dermal exposure to pesticides on housedust-laden indoor surfaces should demonstrate collection efficiencies, for both particles and pesticide residues, which are similar to those that would adhere to the human skin. A spring-loaded press sampler has been developed that approximated the particle- and pesticide-collection efficiencies of a hand press of a human participant. Particle-collection efficiencies for the hand press and EL sampler, using housedust sieved to <250 microm in diameter, indicated that both sampling techniques collected similar particle fractions over the range of particle sizes. Pesticide-collection efficiencies measured on the participants hand (seven paired tests) were 42+/-7% atrazine, 29+/-8% diazinon, 43+/-8% malathion and 21+/-5% chlorpyrifos. The EL sampler collected 35+/-5%, 31+/-3%, 32+/-5% and 18+/-3% respectively. The collection efficiencies of the two sampling techniques were highly correlated for atrazine, diazinon, and chlorpyrifos (correlation coefficient=0.840, 0.815, and 0.706), but not for malathion (correlation coefficient=0.086).

Dust↗
PubMedDate not supplied

House dust levels of selected insecticides and a herbicide measured by the EL and LWW samplers and comparisons to hand rinses and urine metabolites.

During the Minnesota Children's Pesticide Exposure Study (MNCPES), comparisons were made between the insecticide/herbicide loadings obtained with two household dust/insecticide or herbicide samplers: the Edwards and Lioy (EL) press sampler (used for dust collection from carpets or other surfaces) and the Lioy, Waimnan and Weisel (LWW) surface wipe sampler. The results were compared with hand rinse levels, and urine metabolite levels obtained from 102 children (ages 3-13). All measurements were made during a 1-week sampling period, and information was obtained on household pesticide use and each child's activities. Of the homes, <5% had recent spot uses of a pesticide but none had recent general applications. The analyses focused primarily on atrazine (a herbicide), and malathion, diazinon, and chlorpyrifos (insecticides). Metabolites were measured for atrazine, malathion and chlorpyrifos. The atrazine levels obtained using the EL indicate that this compound was transported into the home by an unquantified transport mechanism (e.g. tracking of soil). Two malathion hand rinse values exceeded >170 ng/cm2, suggesting that since indoor surface levels were low, these children had other sources of exposure. Atrazine, chlorpyrifos and malathion were detectable in >30% of the homes by the EL, LWW or hand rinse. Only chlorpyrifos had detectable levels in > or = 50% of the samples for all types, i.e. compound or metabolite, which is consistent with it being a common household pesticide. The median (and maximum) chlorpyrifos levels for the EL surface, EL carpet, LWW surface (two rooms), hand rinse, and urine metabolites were: 0.07 (32.6) ng/cm2; 0.07 (44.5) ng/cm2; 0.34 (3.64) ng/cm2; 0.42 (14.4) ng/cm2; 0.03 (2.14) ng/hand and 6.9 (59.0) microg/g, respectively. A strong correlation was found for chlorpyrifos between the EL surface and carpet samples. Chlorpyrifos levels detected by LWW had a different distribution and concentration range than the EL, indicating that it collected more than the surface dislodgeable insecticide. EL was directly comparable to the hand rinse or urine levels, but only the LWW had a weak correlation with hand rinse levels, suggesting that the children had other sources of chlorpyrifos exposure. Thus, mechanistic exposure studies are needed to more accurately establish exposure dose relationships in residential settings.

Adolescent↗
PubMedDate not supplied

Quantitative analysis of children's microactivity patterns: The Minnesota Children's Pesticide Exposure Study.

The National Human Exposure Assessment Survey (NHEXAS)/Minnesota Children's Pesticide Exposure Study (MNCPES) was a population-based study designed to characterize children's exposure to residential pesticides and to evaluate the contribution of residential and children's activities to children's exposure. Families of 168 children were surveyed for residential use of pesticides and children's activities. From these homes, families of 102 children between the ages of 3 and 13 years participated in a week-long intensive exposure study. Of the 102 children, 19 children were videotaped for four consecutive hours in their normal daily activities. The survey responses indicated that the youngest children were more likely to exhibit behaviors that would foster exposure to environmental contaminants. Comparison of questionnaire responses indicated that the videotaped subsample was representative of the exposure study population. The microactivities of the videotaped children that might contribute to their exposure via ingestion or dermal routes were quantified. Hand-to-mouth and object-to-mouth activities were observed most frequently among the youngest children. The youngest children were also most likely to be barefoot both indoors and outside. Gender differences were found in mouthing behavior and the proportion of observed time spent outdoors.

Activities of Daily Living↗
PubMedDate not supplied

Intrathecal morphine as analgesia for labor pain.

In this descriptive study of intrathecal morphine sulfate used for pain control during labor, 49 parturients received morphine intrathecally, 78 were administered butorphanol tartrate (Stadol), and 34 received no analgesia. Significant differences for the intrathecal group included: (1) decreased requirement of nitrous oxide for delivery, (2) lower number of doses of postpartum intramuscular pain medication, and (3) increased use of forceps. The intrathecal morphine group showed no prolongation of labor and no major side effects in mothers or newborns. The results suggest that the use of lower levels of intrathecal morphine sulfate (0.5 mg) is as safe and effective as the more traditional intravenous analgesia for labor.

Anesthesia, Intravenous↗