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Biomedical subjects

E Johnson

Publications and source records attributed to E Johnson.

At least 73 records · Page 4Linked to original sources
PubMed2001

Morbidity and functional outcome after restorative proctocolectomy for ulcerative colitis.

OBJECTIVE: To find out whether a threefold increase in follow up (median 108 compared with 36 months) influenced major morbidity and functional outcome between the first 32 and the last 32 patients consecutively operated on with J-pouch ileoanal anastomosis for ulcerative colitis from 1984 to 1997. DESIGN: Retrospective and prospective study. SETTING: University hospital, Norway. PATIENTS: 64 patients with ulcerative colitis who had proctocolectomy and ileal pouch-anal anastomoses. INTERVENTIONS: The pouches were mainly hand anastomosed (n = 61) to the dentate line after mucosectomy or anastomosed by double stapling technique without mucosectomy (n = 3). The 58 patients who still had their pouches responded to a questionnaire on functional outcome and satisfaction. MAIN OUTCOME MEASURES: Morbidity, functional outcome, and patients' satisfaction. RESULTS: Major morbidity in these 64 patients comprised pelvic sepsis in 3 (5%), operation for intestinal obstruction in 5 (8%), pouchitis in 12 (19%), fistulas in 7 (11%) and pouch excision in 6 (9%). Thirteen patients (20%) had 35 reoperations and 11 patients (17%) had 22 re-laparotomies. There were more complications among the first 32 patients with the longest follow up than among the last 32 patients, but this difference was significant only concerning the rate of reoperations (31% compared with 9%) because of the higher number of pouch excisions (5 compared with 1) in this group. There were no significant differences in the functional outcome and degree of patient satisfaction between the first 29 and the last 29 patients. Respective values for 24 hour median stool freqency were 7.0 and 6.3, leakage of stool 48% and 38%, ability to defer defaecation 86% and 97%, perineal irritation 59% and 48%, use of antidiarrhoeal medication 55% and 52%, and wearing of pad 28% and 38%. Sexual life (n = 57) was improved in 11 (19%) and reduced in 7 (12%). Potency was reduced in 5 (15%) and ejaculation in 4 (12%), one of whom (3%) had retrograde ejaculation. Three (5%) received disability pensions and five (9%) had reduced workload. After the pouch operation 48 (91%) felt better and 3 (6%) felt worse because of frequent bowel emptying, perineal eczema, or pouch fistula. CONCLUSION: Continence-preserving proctocolectomy carries considerable morbidity, but the long term functional outcome is satisfactory and does not seem to deteriorate substantially.

Adolescent↗
PubMed2001

Detection of mRNA for the terminal complement components C5, C6, C8 and C9 in human umbilical vein endothelial cells in vitro.

Human umbilical vein endothelial cells (HUVEC) have previously been shown to synthesize the functional terminal pathway of complement based on the detection by radioimmunoassay of the terminal complement complex (TCC) on coincubated agarose beads. In addition, C7 secretion by these cells in amounts comparable to C3, as well as C7 mRNA, has recently been demonstrated. However, it has not been possible to detect C5-6 and C8 in the fluid phase, and only trace amounts of soluble C9. Against this background we examined whether mRNA for the remaining terminal complement factors was present in HUVEC. By the use of reverse transcription (RT)-polymerase chain reaction (PCR) and Northern blot the presence of mRNA for complement factors C5, C6, C8 and C9 was demonstrated.

Base Sequence↗
PubMed2001

Properties of a thermostable nitrate reductase from the hyperthermophilic archaeon Pyrobaculum aerophilum.

The nitrate reductase of the hyperthermophilic archaeon Pyrobaculum aerophilum was purified 137-fold from the cytoplasmic membrane. Based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, the enzyme complex consists of three subunits with apparent molecular weights of 130,000, 52,000, and 32,000. The enzyme contained molybdenum (0.8-mol/mol complex), iron (15.4-mol/mol complex) and cytochrome b (0.49-mol/mol complex) as cofactors. The P. aerophilum nitrate reductase distinguishes itself from nitrate reductases of mesophilic bacteria and archaea by its very high specific activity using reduced benzyl viologen as the electron donor (V(max) with nitrate, 1,162 s(-1) (326 U/mg); V(max) with chlorate, 1,348 s(-1) (378 U/mg) [assayed at 75 degrees C]). The K(m) values for nitrate and chlorate were 58 and 140 microM, respectively. Azide was a competitive inhibitor and cyanide was a noncompetitive inhibitor of the nitrate reductase activity. The temperature optimum for activity was > 95 degrees C. When incubated at 100 degrees C, the purified nitrate reductase had a half-life of 1.5 h. This study constitutes the first description of a nitrate reductase from a hyperthermophilic archaeon.

Enzyme Stability↗
PubMed2001

Serum hormone levels in humans with low serum concentrations of 2,3,7,8-TCDD.

We measured current serum hormone and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) concentrations in 37 men who sprayed 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) in the State of Victoria, Australia. TCDD levels were consistently significantly inversely related to prolactin levels in all analyses. In correlation analyses, TCDD levels were also inversely related to triiodothyronine (T3), thyroid-stimulating hormone (TSH), and testosterone levels, and positively associated with glucagon levels. The mean serum TCDD concentration in these sprayers was between 2.6 and 8.1 parts per trillion (ppt). Since such TCDD levels are commonly found in the general population in countries such as the US, the results could suggest that background levels of TCDD in the general population could have an effect on hormone levels. The findings are preliminary and need to be replicated in order to evaluate their full public health significance.

Adult↗
PubMed2001

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Ear Protective Devices↗
PubMed2001

Changes in mRNA levels of the Myoc/Tigr gene in the rat eye after experimental elevation of intraocular pressure or optic nerve transection.

PURPOSE: To isolate the rat Myoc/Tigr gene and investigate changes in its expression pattern in normal eyes and in eyes with either pressure-induced optic nerve damage or optic nerve transection. METHODS: Expression pattern of the rat Myoc/Tigr gene was investigated by Northern blot hybridization. Optic nerve damage and death of ganglion cells in the retina were induced unilaterally, by injection of hypertonic saline solution, episcleral vein cauterization, or optic nerve transection. The levels of mRNA for Myoc/Tigr were compared between several tissues of the control and surgically altered eyes, by using semiquantitative RT-PCR, real-time PCR, and Northern blot analysis. RESULTS: The rat Myoc/Tigr gene is 10 kb long and contains three exons. Among the eye tissues analyzed, Myoc/Tigr mRNA was detected in the combined tissues of the eye angle, sclera, cornea, retina, and optic nerve head. With pressure-induced optic nerve degeneration, the level of Myoc/Tigr mRNA decreased in the retina and the combined tissues of the eye angle, but increased in the optic nerve head. After optic nerve transection, the level of Myoc/Tigr mRNA increased in the retina, but did not change in the combined tissues of the eye angle. CONCLUSIONS: The decreased level of Myoc/Tigr mRNA in the retina after induction of elevated intraocular pressure compared with that in the control retina cannot be explained by ganglion cell death alone. Differences in Myoc/Tigr mRNA levels in eye tissues after elevation of intraocular pressure or optic nerve transection may reflect the activation of different signaling pathways involved in regulation of this gene.

Animals↗
PubMed2000

Measurements of the mass, total width, and two-photon partial width of the eta(c) meson.

Using 13.4 fb(-1) of data collected with the CLEO detector at the Cornell Electron Storage Ring, we have observed 300 events for the two-photon production of ground-state pseudoscalar charmonium in the decay eta(c)-->K(0)(S)K-/+pi(+/-). We have measured the eta(c) mass to be [2980.4+/-2.3 (stat)+/-0.6 (syst)] MeV and its full width as [27.0+/-5.8 (stat)+/-1.4 (syst)] MeV. We have determined the two-photon partial width of the eta(c) meson to be [7.6+/-0.8 (stat)+/-0.4 (syst)+/-2.3 (br)] keV, with the last uncertainty associated with the decay branching fraction.

Journal Article↗
PubMed2000

Charged-particle multiplicity near midrapidity in central Au+Au collisions at sqrt[SNN]=56 and 130 GeV.

We present the first measurement of pseudorapidity densities of primary charged particles near midrapidity in Au+Au collisions at sqrt[s(NN)] = 56 and 130 GeV. For the most central collisions, we find the charged-particle pseudorapidity density to be dN/deta|(|eta|<1) = 408+/-12(stat)+/-30(syst) at 56 GeV and 555+/-12(stat)+/-35(syst) at 130 GeV, values that are higher than any previously observed in nuclear collisions. Compared to proton-antiproton collisions, our data show an increase in the pseudorapidity density per participant by more than 40% at the higher energy.

Journal Article↗
PubMed2000

Molecular detection of an Ehrlichia-like agent in rainbow trout (Oncorhynchus mykiss) from Northern California.

Ehrlichia DNA was identified by nested PCR in rainbow trout (Oncorhynchus mykiss) collected from a creek in northern California where Potomac horse fever is endemic. Ehrlichia DNA was found in tissues from several organs including the gills, heart, spleen, liver, kidneys and intestine of trout and from three different adult digenetic trematodes (Deropegus sp., Crepidostomum sp., Creptotrema sp.) parasitizing the gallbladder and/or the intestine of the trout. Sequencing of PCR-amplified DNA from the 16S rRNA gene indicated that the source organism was most closely related to the sequences of E. risticii (level of sequence similarity 96.0%), the SF agent (95.9%), E. sennetsu (95.8%), and Neorickettsia helminthoeca (95.3%). The data suggest that trout and parasitic trematodes may be involved in the epidemiology of an Ehrlichia-like agent belonging to the E. sennetsu genogroup. Whether the fish agent infects horses, dogs, or human beings, and whether it causes disease, remain to be determined.

Animals↗
PubMed2000

Infection rate of Ehrlichia risticii, the agent of Potomac horse fever, in freshwater stream snails (Juga yrekaensis) from northern California.

Juga yrekaensis freshwater snails were tested for trematode stages and for Ehrlichia risticii DNA using a nested PCR assay. Snails were collected monthly from two Potomac horse fever (PHF) endemic locations in northern California (Montague and Weed). The trematode infection rate varied between 40 and 93.3% in large snails (shell size >15mm) and between 0 and 13.3% in small snails (<15mm). The highest trematode infection rate for large and small snails was recorded in September and the lowest infection rate for large snails was recorded in June (Weed) and October (Montague). The E. risticii PCR infection rate among small snails from both sites was similar and varied monthly between 0 and 3.3%. The PCR infection rate for large snails from Weed was high in May (20.0%) and decreased progressively until November (10.0%). The PCR infection rate for large snails from Montague was 5.0% in May, 26.3% in August and 16. 7% in October. PCR-positive snails were always related to the microscopic detection of trematode stages (virgulate cercariae). This study provides evidence that J. yrekaensis are infected with trematode cercariae that harbor E. risticii. The number of snails harboring trematode stages and the number of PCR positive snails varied with the size of the snails, the month of collection, and the geographic origin.

Animals↗
PubMed2000

High-gain harmonic-generation free-electron laser

A high-gain harmonic-generation free-electron laser is demonstrated. Our approach uses a laser-seeded free-electron laser to produce amplified, longitudinally coherent, Fourier transform-limited output at a harmonic of the seed laser. A seed carbon dioxide laser at a wavelength of 10.6 micrometers produced saturated, amplified free-electron laser output at the second-harmonic wavelength, 5.3 micrometers. The experiment verifies the theoretical foundation for the technique and prepares the way for the application of this technique in the vacuum ultraviolet region of the spectrum, with the ultimate goal of extending the approach to provide an intense, highly coherent source of hard x-rays.

Journal Article↗
PubMed2000

Native and heterologous neuropeptides are cardioactive in Drosophila melanogaster.

Nine neuropeptides isolated from Drosophila melanogaster and five neuropeptides, previously isolated from the CNS of Limulus with antisera to FMRFamide-related peptides, were tested for their effects on the myogenic heart of Drosophila melanogaster. Of the native peptides, TDVDHVFLRF-NH(2) (Dromyosuppressin), DPKQDFMRFamide, and PDNFMRFamide significantly slowed the heart. Of the Limulus peptides, DEGHKMLYFamide (LP1) increased heart rate significantly, GHSLLHFamide (LP2) and PDHHMMYFamide (LP3) decreased the heart's rate, while DHGNMLYFamide (LP4) and GGRSPSLRLRFamide (LP5) had no effect at the concentrations we employed. Dromyosuppressin, DPKQDFMRFamide, and PDNFMRFamide from Drosophila, and LP2 and LP3 from Limulus, which belong to a novel group of peptides structurally unrelated to FMRFamide, are among only a very few substances from within the general group of neuropeptides and neurohormones known to slow the heart of Drosophila, and as such offer an important tool for investigating the molecular mechanisms underlying the control of the pacemaker.

Journal Article↗
PubMed2000

A genetic analysis of crystal growth.

The regulation of crystal morphology by proteins is often observed in biology. It is a central feature in the formation of hard tissues such as bones, teeth and mollusc shells. We have developed a genetic system in the bacterium Escherichia coli to study the protein-mediated control of crystal growth. We have used the crystallization of gold as a model system and found polypeptides that control the morphology of the resulting gold crystals. Analysis of the crystallization process influenced by these polypeptides indicates they act catalytically by an acid mechanism. Our results suggest that the concepts and methods of microbial genetics are general and can be applied to substances not commonly found in biological systems.

Acids↗
PubMed2000

Study of exclusive radiative B meson decays

We have studied exclusive, radiative B meson decays to charmless mesons in 9.7x10(6) B&Bmacr; decays accumulated with the CLEO detector. We measure B(B0-->K(*0)(892)gamma) = (4.55(+0.72)(-0. 68)+/-0.34)x10(-5) and B(B+-->K(*+)(892)gamma) = (3.76(+0.89)(-0. 83)+/-0.28)x10(-5). We have searched for CP asymmetry in B-->K(*)(892)gamma decays and measure A(CP) = +0.08+/-0.13+/-0.03. We report the first observation of B-->K(*)(2)(1430)gamma decays with a branching fraction of (1.66(+0.59)(-0.53)+/-0.13)x10(-5). No evidence for the decays B-->rhogamma and B0-->omegagamma is found and we limit B(B-->(rho/omega)gamma)/B(B-->K(*)(892)gamma)<0.32 at 90% C.L.

Journal Article↗
PubMed2000

Cardiopulmonary resuscitation by chest compression alone or with mouth-to-mouth ventilation.

BACKGROUND: Despite extensive training of citizens of Seattle in cardiopulmonary resuscitation (CPR), bystanders do not perform CPR in almost half of witnessed cardiac arrests. Instructions in chest compression plus mouth-to-mouth ventilation given by dispatchers over the telephone can require 2.4 minutes. In experimental studies, chest compression alone is associated with survival rates similar to those with chest compression plus mouth-to-mouth ventilation. We conducted a randomized study to compare CPR by chest compression alone with CPR by chest compression plus mouth-to-mouth ventilation. METHODS: The setting of the trial was an urban, fire-department-based, emergency-medical-care system with central dispatching. In a randomized manner, telephone dispatchers gave bystanders at the scene of apparent cardiac arrest instructions in either chest compression alone or chest compression plus mouth-to-mouth ventilation. The primary end point was survival to hospital discharge. RESULTS: Data were analyzed for 241 patients randomly assigned to receive chest compression alone and 279 assigned to chest compression plus mouth-to-mouth ventilation. Complete instructions were delivered in 62 percent of episodes for the group receiving chest compression plus mouth-to-mouth ventilation and 81 percent of episodes for the group receiving chest compression alone (P=0.005). Instructions for compression required 1.4 minutes less to complete than instructions for compression plus mouth-to-mouth ventilation. Survival to hospital discharge was better among patients assigned to chest compression alone than among those assigned to chest compression plus mouth-to-mouth ventilation (14.6 percent vs. 10.4 percent), but the difference was not statistically significant (P=0.18). CONCLUSIONS: The outcome after CPR with chest compression alone is similar to that after chest compression with mouth-to-mouth ventilation, and chest compression alone may be the preferred approach for bystanders inexperienced in CPR.

Aged↗
PubMed2000

Search for the decay &Bmacr;(0)-->D(*0)gamma

We report results of a search for the rare radiative decay &Bmacr;(0)-->D(*0)gamma. Using 9.66x10(6) B&Bmacr; meson pairs collected with the CLEO detector at the Cornell Electron Storage Ring, we set an upper limit on the branching ratio for this decay of 5.0x10(-5) at 90% C.L. This provides evidence that the anomalous enhancement is absent in W-exchange processes and that weak radiative B decays are dominated by the short-distance b-->sgamma mechanism in the standard model.

Journal Article↗
PubMed2000

Food-neophobia in semi-free ranging rhesus macaques: effects of food limitation and food source.

This study characterizes food neophobia in semi-free ranging rhesus macaques. In experiment one, monkeys received novel and familiar foods during periods of normal provisioning and when provisioning was suspended. The monkeys did discriminate between novel and familiar foods and continued to exhibit neophobia when provisioning was suspended. In experiment two, food was either tossed to subjects or placed in the habitat so that monkeys discovered food without the observer in close proximity. Rhesus macaques were more likely to eat a novel food that was hand-tossed to them compared to food they discovered in their habitat. This study suggests that food neophobia is a robust trait in rhesus macaques and that a history of provisioning may affect the expression of the trait.

Animal Feed↗