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Biomedical subjects

W Edwards

Publications and source records attributed to W Edwards.

At least 37 records · Page 2Linked to original sources
PubMed1989

Detection of colonies of Anaplasma marginale in salivary glands of three Dermacentor spp infected as nymphs or adults.

Salivary glands from males of 3 Dermacentor species (D andersoni, D variabilis and D occidentalis) that were infected with either the Virginia or Idaho isolate of Anaplasma marginale as nymphs or adults were examined for colonies of A marginale by use of light and electron microscopy. Prior to dissection of salivary glands, exposed ticks were held at 25 C for 15 to 18 days, followed by a 3-day incubation at 37 C. Ticks of 2 species transmitted A marginale to calves; the third tick species was confirmed infected by demonstration of typical colonies in tick gut cells, but transmission was not attempted; Colonies of A marginale were seen with light microscopy in salivary glands of all 3 species of ticks; they were located in acinar cells that contained simple granules. Colonies varied morphologically from small, compact ones to larger structures that contained distinct organisms and often were adjacent to the host cell nucleus. Electron microscopy confirmed that the colonies were rickettsial organisms. Morphologic features of A marginale varied and included reticulated forms, forms with electron-dense centers, and small particles; these various forms were similar to those described previously in midgut epithelial cells of ticks. We believe that the organism seen within tick salivary glands may replicate in the glands before its transmission to the vertebrate host.

Anaplasma↗
PubMed1988

Chronic hypoxia alters structure and transmitter dynamics in dog pulmonary artery.

Confinement of dogs to 10% oxygen for 14 days caused erythropoiesis and pulmonary hypertension. Histological sections of the lung tissue showed thickening of the smooth muscle component of muscular arteries and arterioles. Segments of pulmonary artery from dogs exposed to hypoxia were superfused under continuation of hypoxic conditions or after return to oxygenated conditions. Parallel segments of pulmonary artery from normal dogs were also studied. Norepinephrine stores were labeled with [3H]norepinephrine and measurements were made of [3H]norepinephrine and its radiolabeled metabolites (separated by column chromatography) in superfusates using liquid scintillation spectrometry. Chronic hypoxia (1) reduced neuronal uptake of NE from synaptic clefts, (2) reduced the content of DOPEG in superfusate from tissues studied during continuation of hypoxic conditions and in tissues studied after return to oxygenated conditions, (3) increased extraneuronal uptake of NE and (4) increased overflow of NE from synaptic clefts. In similar segments of pulmonary artery removed from the same lung, endogenous free and conjugated norepinephrine and dopamine were measured in pulmonary artery by liquid chromatography with electrochemical detection. The tissue content of free norepinephrine after stimulation was reduced, which was compatible with the reduction in neuronal uptake. Conjugated norepinephrine was a minor metabolite and was increased modestly compared to concentrations reported previously in pulmonary artery from normal dogs.

Animals↗
PubMed1988

Variability in 28-day outcomes for very low birth weight infants: an analysis of 11 neonatal intensive care units.

A retrospective study of all infants weighing 701 to 1,500 g born at 11 neonatal intensive care centers during 1983 and 1984 was performed to determine whether two specific 28-day outcomes, survival and survival without the need for supplemental oxygen, varied among the centers. Survival without the need for supplemental oxygen was chosen as a reflection of infants surviving without chronic lung disease. There were 1,776 live-born infants delivered during the 2-year study period. Of these infants, 85% (1,512) survived 28 days, a range of 80% to 92% at the individual centers. A total of 60% (1,056) of the infants were alive without supplemental oxygen on day 28, a range of 51% to 70% at the individual centers. Multivariate analysis demonstrated that both survival on day 28 (chi 2 = 23.9, P less than .01) and survival without supplemental oxygen on day 28 (chi 2 = 44.2, P less than .0001) varied significantly among centers after the effects of birth weight, gender, and race were taken into account. Female gender, nonwhite race, and increased birth weight were factors associated with improved rates of survival and survival without supplemental oxygen. The magnitude of outcome variation among centers was estimated by using the logistic regression models to predict what the outcomes would be if each center were to treat a standardized population consisting of all 1,776 study infants.(ABSTRACT TRUNCATED AT 250 WORDS)

Birth Weight↗
PubMed1987

Persistence of colonies of Anaplasma marginale in overwintering Dermacentor variabilis.

Dermacentor variabilis were infected as nymphs with Anaplasma marginale by allowing the ticks to feed on a single infected donor calf. Two weeks after molting to the adult stage, the ticks were allotted into 1 of 3 groups and were allowed to overwinter at room temperature (25 C) in the laboratory (group 1), cold storage (4.5 C) in the laboratory (group 2), or outdoors in leaf litter (group 3). Persistence of A marginale was assessed by determining density of colonies (number of colonies/0.1 mm2 of gut tissue examined) in tick gut specimens at 3, 5, 7, 9, and 12 months after molting to the adult stage. Colonies of A marginale were found in all groups at every density evaluation period. Highest colony densities were observed uniformly in specimens collected at month 7 (May); densities decreased at month 9 and were lowest at month 12. Statistical analysis indicated that ticks subjected to cold storage and to outdoor conditions had similar colony densities of A marginale; the density curve in these 2 groups indicated significant quadratic effects over time, with peak densities in May. Mean colony density in ticks kept at room temperature fit a different quadratic equation. The morphologic data indicated that A marginale overwinters in Dermacentor variabilis, and that increasing numbers of organisms are found from January to May.

Anaplasma↗
PubMed1986

Longevity of colonies of Anaplasma marginale in midgut epithelial cells of Dermacentor andersoni.

Colonies of Anaplasma marginale in midgut epithelial cells of experimentally infected Dermacentor andersoni were studied in adult ticks 1, 3, and 6 months old. Longevity of the parasite in ticks was assessed by evaluating its infectivity for splenectomized calves; calves were exposed by feeding ticks and by inoculation of tick gut homogenates. Longevity was also evaluated by determining size, type, and density of colonies in male and female ticks. The effect of incubation (2.5 days at 37 C) on colony density was also examined for ticks at each age period. All methods used to assess longevity of A marginale in ticks (tick transmission, calf inoculation, and histologic studies) indicated a decrease of the numbers of organisms in 6-month-old ticks. Furthermore, when tick gut homogenates from 6-month-old nonincubated ticks were not infectious for susceptible calves, incubation of ticks before dissection restored infectivity of homogenates. Colonies of A marginale were detected in gut tissues of 6-month-old ticks that were not infective; therefore, infectivity of ticks could not be confirmed merely by presence of A marginale colonies.

Anaplasma↗
PubMed1983

Etodolac, aspirin, and placebo in patients with rheumatoid arthritis: a 12-week study.

Etodolac, aspirin, and placebo were evaluated for efficacy and safety in 18 patients with adult-onset, active rheumatoid arthritis. This was a 12-week, double-blind, parallel-group study divided into drug titration and maintenance periods and preceded by a washout period of up to two weeks. The mean daily maintenance doses of etodolac and aspirin were 394 mg and 4,414 mg, respectively. Etodolac was significantly (P less than or equal to 0.05) more effective than placebo in five of ten clinical variables of efficacy: number of painful joints, number of swollen joints, pain intensity, erythrocyte sedimentation rate, and patients' overall assessments. Aspirin was significantly more effective than placebo in only two assessments: number of painful joints and pain intensity. One patient on etodolac, two patients on aspirin, and four patients on placebo had to be withdrawn from the trial because of insufficient therapeutic response. One patient in the placebo group was withdrawn from the study because of a pruritic rash. Mild to moderate gastrointestinal complaints occurred in all three treatment groups: in three patients taking etodolac, three taking aspirin, and two taking placebo.

Acetates↗
PubMed1980

Atrial septal defect (sinus venosus type) in a dog.

A 2-year-old Old English Sheepdog had right-side congestive heart failure characterized by pericardial effusion, pleural effusion, ascites, and increased pulmonary wedge pressure. A diagnosis of atrial septal defect was made by means of cardiac catheterization and angiography. Surgical correction initially was deferred because of pulmonary hypertension. However, when congestive heart failure could not be managed adequately, surgical correction was attempted. Postsurgically, thrombocytopenia developed and that led to bleeding, oliguira, and pulmonary edema. The bleeding was controlled by whole blood transfusion, but the oliguria and pulmonary edema were not resolved, even with intensive diuretic therapy. The dog died 24 hours after surgery.

Angiography↗
PubMed1980

Microsurgery in otolaryngology: the future.

Five areas of active clinical research development in otolaryngology have been selected to illustrate the specific applications of microsurgical principles and the potential future of associated bioengineering research. These are: (i) biocompatible microelectronic circuitry and cochlear electrode implant in total cochlear deafness, with preservation of auditory nerve function; (ii) microneural surgery of the facial nerve in hemifacial spasm and the techniques available for reinnervation of the paralysed larynx; (iii) laser microsurgery of the larynx--a new surgical modality dependent on high-precision control through the operating microscope; (iv) microvascular free tissue transfer in head and neck reconstruction and its potential value following combined irradiation therapy for carcinoma; and (v) human laryngeal transplantation--its current status.

Cochlear Implants↗
PubMed1979

The isolation and partial characterization of the plasma membrane from Trypanosoma brucei.

Whole sheets of plasma membrane, each with their attached flagellum, were purified from Trypanosoma brucei. The method devised for their isolation included a new technique of cell breakage that used a combination of osmotic stress followed by mechanical sheer and avoided the problem of extreme vesiculation as well as the trapping of organelles in cell 'ghosts'. The purified membranes all contained the pellicular microtubular array. The antigenic surface coat was completely released from the plasma membrane during the isolation procedure. The membranes had a very high cholesterol/phospholipid ratio (1.54). A large proportion (42%) of the cellular DNA was recovered in the plasma-membrane fraction unless a step involving deoxyribonuclease treatment, which decreased the DNA content to less than 13%, was included before secrose-density gradient centrifugation. This step also aided the separation of plasma membranes from other cellular components. The ouabain-sensitive Na+ + K+-stimulated adenosine triphosphatase and adenylate cyclase co-purified with the plasma membranes. Although 5'-nucleotidase was thought to be a plasma-membrane component, it was easily detached from the membrane. The purified membranes were essentially free of L-alanine-alpha-oxoglutarate aminotransferase, L-asparte-alpha-oxoglutarate aminotransferase, malate dehydrogenase, oligomycin-sensitive adenosine triphosphatase, glucose 6-phosphatase, Mg2+-stimulated p-nitrophenyl phosphatase and catalase.

Cell Fractionation↗
PubMed1977

Variable phenotypic expression of an X-linked recessive lymphoproliferative syndrome.

Investigation of a family with cancer in boys revealed that at least 20 males had the X-linked recessive lymphoproliferative syndrome. A variety of phenotypes occurred: aproliferative phenotypes consisted of aplastic anemia, agranulocytosis or acquired hypogammaglobulinemia; and proliferative phenotypes of B cells included disorders associated with the Epstein-Barr virus, American Burkitt's lymphoma, immunoblastic sarcoma of B cells, fatal infectious mononucleosis or plasmacytoma. The lymphoproliferative disorders observed in males could have resulted from an immunodeficiency to Epstein-Barr virus. The variable phenotypic expression could have resulted from individual differences in the viral dose, duration of exposure and age at which the boys were exposed to the virus. Aproliferative phenotypes such as acquired hypogammaglobulinemia could have ensued from excessive suppressor-cell activity on B cells, whereas proliferative phenotypes such as Burkitt's lymphoma or fatal infectious mononucleosis could have resulted from infection by Epstein-Barr virus and failure to stop proliferation of B cells.

Adolescent↗
PubMed1977

Synchronous VBM and radiotherapy in the treatment of squamous cell carcinoma of the head and neck.

Since April 1974, 60 patients with squamous cell carcinoma of the head and neck region, of poor prognosis and generally in advanced stages, were treated with the combination of a cytotoxic regimen--VBM (Vincristine, Bleomycin and Methotrexate) and radical radiotherapy. The essential feature of the combination is the administration of pulses of VBM synchronous with a course of fractionated external radiotherapy in order to achieve potentiation of radiotherapy. On average 4-5 pulses of VBM were given during treatment, combined with radiotherapy on a Cobalt unit. The selection, preparation and management of the patients are described. Intense mucositis and intercurrent infection provide the main problems during treatment and close management is essential. Late complications have not been a serious problem. The crude actuarial survival rate at 24 months is 61%. The probability of survival without any recurrence to 24 months following initial treatment is 46%. Local control was achieved by the initial treatment in 43 patients. These results suggest that potentiation of radiotherapy and an increased therapeutic ratio has been obtained by the addition of VBM to radiotherapy and there is a possibility that the occurrence of distant metastases has been reduced or postponed.

Bleomycin↗
PubMed1976

Anatomically corrected malposition of the great arteries (S,L,D).

The following is the first case of anatomically corrected malposition of the (S, L, D) type clinically diagnosed antemortem and only the second case recorded in the literature. The (S, L, D) notation indicates the segmental set of situs solitus of viscera and atria (S), ventricular l-loop (L), and d-malposition of the great arteries (D). This rare anomaly has the physiologic findings of complete d-transposition. Attempted surgical palliation was unsuccessful.

Autopsy↗