| 1. |
- Egholm, M., et al.
(författare)
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PNA HYBRIDIZES TO COMPLEMENTARY OLIGONUCLEOTIDES OBEYING THE WATSON-CRICK HYDROGEN-BONDING RULES
- 1993
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 365:6446, s. 566-568
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Tidskriftsartikel (refereegranskat)abstract
- DNA ANALOGUES are currently being intensely investigated owing to their potential as gene-targeted drugs1-3. Furthermore, their properties and interaction with DNA and RNA could provide a better understanding of the structural features of natural DNA that determine its unique chemical, biological and genetic properties3,4. We recently designed a DNA analogue, PNA, in which the backbone is structurally homomorphous with the deoxyribose backbone and consists of N-(2-aminoethyl)glycine units to which the nucleobases are attached5-9. We showed that PNA oligomers containing solely thymine and cytosine can hybridize to complementary oligonucleotides, presumably by forming Watson-Crick-Hoogsteen (PNA)2-DNA triplexes, which are much more stable than the corresponding DNA-DNA duplexes5-7, and bind to double-stranded DNA by strand displacement5,8. We report here that PNA containing all four natural nucleobases hybridizes to complementary oligonucleotides obeying the Watson-Crick base-pairing rules, and thus is a true DNA mimic in terms of base-pair recognition.
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| 2. |
- Knipp, D.J., et al.
(författare)
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Ionospheric Convection Response to Slow, Strong Variations in a Northward Interplanetary Magnetic Field: A Case Study for January 14, 1988
- 1993
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 98, s. 19273-19292
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Tidskriftsartikel (refereegranskat)abstract
- We analyze ionospheric convection patterns over the polar regions during the passage of an interplanetary magnetic cloud on January 14, 1988, when the interplanetary magnetic field (IMF) rotated slowly in direction and had a large amplitude. Using the assimilative mapping of ionospheric electrodynamics (AMIE) procedure, we combine simultaneous observations of ionospheric drifts and magnetic perturbations from many different instruments into consistent patterns of high-latitude electrodynamics, focusing on the period of northward IMF. By combining satellite data with ground-based observations, we have generated one of the most comprehensive data sets yet assembled and used it to produce convection maps for both hemispheres. We present evidence that a lobe convection cell was embedded within normal merging convection during a period when the IMF B(y) and B(z) components were large and positive. As the IMF became predominantly northward, a strong reversed convection pattern (afternoon-to-morning potential drop of around 100 kV) appeared in the southern (summer) polar cap, while convection in the northern (winter) hemisphere became weak and disordered with a dawn-to-dusk potential drop of the order of 30 kV. These patterns persisted for about 3 hours, until the IMF rotated significantly toward the west. We interpret this behavior in terms of a recently proposed merging model for northward IMF under solstice conditions, for which lobe field lines from the hemisphere tilted toward the Sun (summer hemisphere) drape over the dayside magnetosphere, producing reverse convection in the summer hemisphere and impeding direct contact between the solar wind and field lines connected to the winter polar cap. The positive IMF B(x) component present at this time could have contributed to the observed hemispheric asymmetry. Reverse convection in the summer hemisphere broke down rapidly after the ratio \textbackslashB(y)/B(z)\textbackslash exceeded unity, while convection in the winter hemisphere strengthened. A dominant dawn-to-dusk potential drop was established in both hemispheres when the magnitude of B(y) exceeded that of B(z), with potential drops of the order of 100 kV, even while B(z) remained northward. The later transition to southward B(z) produced a gradual intensification of the convection, but a greater qualitative change occurred at the transition through \textbackslashB(y)/B(z)\textbackslash = 1 than at the transition through B(z) = 0. The various convection patterns we derive under northward IMF conditions illustrate all possibilities previously discussed in the literature: nearly single-cell and multicell, distorted and symmetric, ordered and unordered, and sunward and antisunward.
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| 3. |
- Larsson, P G, et al.
(författare)
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Advantage or disadvantage of episiotomy compared with spontaneous perineal laceration.
- 1991
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Ingår i: Gynecologic and obstetric investigation. - : S. Karger AG. - 0378-7346 .- 1423-002X. ; 31:4, s. 213-6
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Tidskriftsartikel (refereegranskat)abstract
- In a prospective clinical investigation of 2,144 deliveries, we elucidate the indications for episiotomy and how different methods of anesthesia affect the frequency of episiotomy and the perineal problems after episiotomy compared with those after spontaneous perineal laceration. We found a significantly higher infection rate (p less than 0.001) and a longer healing period in the episiotomy group. These differences remain even if only primigravida or the indication, imminent perineal laceration, is studied. The results indicate that many women will unnecessarily suffer after an episiotomy. The patient's subjective problems are significantly increased, both immediately and at the 3-month postoperative follow-up.
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| 4. |
- Larsson, P G, et al.
(författare)
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Bacterial vaginosis and the vaginal leucocyte/epithelial cell ratio in women attending an outpatient gynaecology clinic.
- 1991
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Ingår i: European journal of obstetrics, gynecology, and reproductive biology. - : Elsevier BV. - 0301-2115. ; 42:3, s. 217-20
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Tidskriftsartikel (refereegranskat)abstract
- In order to investigate the usefulness of vaginal leucocytosis as a sign of genital infection, vaginal wet smears were obtained from 230 consecutive non-pregnant women attending an outpatient gynaecology clinic. Although 52 (22.6%) of the women were diagnosed as having bacterial vaginosis, none had symptoms of cervicitis or genital infection. Of the patients with bacterial vaginosis 19 (36.5%) had vaginal leucocytosis compared to 37.1% of the women without bacterial vaginosis. In a further study, bacterial vaginosis was also diagnosed in 104 of 384 women (33.3%) attending for first trimester legal abortions. Of the women with bacterial vaginosis 37.5% had vaginal leucocytosis compared to 31.8% for those without bacterial vaginosis (P greater than 0.05). There was no correlation between vaginal leucocytosis and the presence of cervical Chlamydia trachomatis; however, the presence of C. trachomatis did correlate with bacterial vaginosis. Vaginal leucocytes varies with factors unrelated to genital infection. This fact must be taken into consideration when wet smears from patients with suspected genital tract infection are evaluated.
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| 5. |
- Larsson, P. G., et al.
(författare)
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Clue cells in predicting infections after abdominal hysterectomy
- 1991
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Ingår i: Obstetrics and gynecology. - 0029-7844. ; 77:3, s. 450-452
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Tidskriftsartikel (refereegranskat)abstract
- Seventy women scheduled for abdominal hysterectomy were examined for the presence of clue cells in the vaginal discharge in an attempt to identify a possible risk group for development of postoperative infection. Seven of 20 women (35%) with clue cells developed vaginal cuff infections or wound infections, compared with four of 50 women (8%) without clue cells (P less than .01). Women with bacterial vaginosis, diagnosed by air-dried vaginal smears, are therefore at risk for postoperative infection.
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| 6. |
- Larsson, P G, et al.
(författare)
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Is bacterial vaginosis a sexually transmitted disease?
- 1991
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Ingår i: International journal of STD & AIDS. - : SAGE Publications. - 0956-4624 .- 1758-1052. ; 2:5, s. 362-4
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Tidskriftsartikel (refereegranskat)abstract
- The sexual behaviour of 400 women with and 400 women without bacterial vaginosis from a health screening programme was investigated by a questionnaire to see if women with bacterial vaginosis had similar behaviours to women considered at risk for STDs. These patients were randomly selected from computer records. Eight hundred questionnaires were distributed and 641 women answered. The age of first sexual intercourse was lower among women with bacterial vaginosis (17.8 years) than those without (18.6 years; P less than 0.001). Number of lifetime sexual partners was higher among women with bacterial vaginosis (P less than 0.001). Women with bacterial vaginosis smoked or had smoked more often. These results indicate that women with bacterial vaginosis have similar sexual behaviour to those at risk for STDs.
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| 7. |
- Larsson, P G, et al.
(författare)
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The vaginal pH and leucocyte/epithelial cell ratio vary during normal menstrual cycles.
- 1991
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Ingår i: European journal of obstetrics, gynecology, and reproductive biology. - : Elsevier BV. - 0301-2115. ; 38:1, s. 39-41
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Tidskriftsartikel (refereegranskat)abstract
- A higher proportion white blood cells (WBC) than vaginal epithelial cells in wet smears has been accepted as a sign which, together with clinical signs, can be useful in the diagnosis of infections in the genital tract such as cervicitis or salpingitis. However, little is known about the normal variation among healthy women without any symptoms or signs of genital-tract infection. By taking frequent wet smears from three healthy asymptomatic women during four menstrual cycles we found that vaginal leucocytosis usually occurred once each cycle. Normal vaginal leucocytosis must thus be taken into consideration when evaluating wet smear of patients for genital tract infections.
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| 8. |
- Thejls, H., et al.
(författare)
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Expanded gold standard in the diagnosis of Chlamydia trachomatis in a low prevalence population: diagnostic efficacy of tissue culture, direct immunofluorescence, enzyme immunoassay, PCR and serology
- 1994
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Ingår i: Genitourinary medicine. - : BMJ. - 0266-4348. ; 70:5, s. 300-303
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To evaluate the diagnostic efficacy of chlamydia culture, direct immunofluorescence (DFA), direct enzyme immunoassay (EIA), polymerase chain reaction (PCR) and serology by defining positive culture or at least two positive non-culture tests as true positive. SETTING: Three gynaecological departments located in separate areas of Sweden. PATIENTS AND DESIGN: All pregnant women requesting abortion during a six month period were included. In cases with unconfirmed non-culture tests, reculture with multiple passage and PCR on the culture transport medium was performed for confirmation. Serum was analysed for chlamydial antibodies type IgG, IgM and IgA using microimmunofluorescence. RESULTS: 18 of 419 (4.3%) patients were positive for chlamydia according to the defined criteria. Twelve of 419 (2.9%) were positive in standard culture (primary inoculation). The sensitivity of standard culture, DFA, EIA and PCR were 66.7%, 77.8%, 64.7% and 71.4% respectively. The specificity 100% (by definition), 99.5%, 100%, 100% respectively. The positive predictive value 100% (by definition), 87.5%, 100%, 100% respectively. Negative predictive value 98.5%, 99.0%, 98.5%, 98.9% respectively. Serum IgG titre of > or = 64 and > or = 1024 gave positive predictive values of 10% and 21% respectively. CONCLUSIONS: When an expanded gold standard is used, the specificity and positive predictive value of the non-culture tests used are comparable with that of standard culture even in this low prevalence population. Standard culture underestimated the chlamydia prevalence by 33%. The prevalence found represents a decrease from 10 to 2.9% of culture verified chlamydia during four years in comparable populations. Chlamydial antibodies of certain immunological classes are not necessarily present in cases with chlamydia.
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