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Biomedical subjects

M Wulff

Publications and source records attributed to M Wulff.

At least 37 records · Page 2Linked to original sources

A comparison of two methods of securing an endotracheal tube.

While a variety of methods exist for securing an endotracheal tube (ETT), there has been little research on their safety and efficacy. This study aimed to test the equivalence of two methods in three critical care settings by randomly assigning patients to receive either the knot, which requires scissors or blade to remove the ETT tape, or the bow, which can be removed manually. These methods were evaluated by comparing ETT movement, malposition, dislodgement, inadvertent extubation, reduced skin integrity, the cutting of the pilot tube and nurse satisfaction. The 5-month study was conducted in three critical care settings in a large tertiary hospital. Of the 230 patients enrolled, 222 completed the trial. Results, based on a randomised, active control equivalence design, demonstrated the two methods to be equally effective with regard to ETT movement > 2 cm (knot = 21 per cent, bow = 19 per cent; 95 per cent confidence interval for the [2 per cent] difference-8 to 12.5 per cent). The incidence of ETT-related complications was similar for both methods. No pilot tubes were cut using either method. Nurses found that patient mouth care was easier and patient comfort and skin integrity enhanced with the bow method. On the other hand, nurses perceived the knot-tying method to be more secure and easier to apply. Given the equivalence of the two methods, the bow would seem preferable for reasons of safety and comfort.

Adult↗

Infertility in an industrial setting--a population-based study from Northern Sweden.

OBJECTIVE: To analyze the possible environmental effects on infertility among couples living in the immediate neighborhood of a smelter and to study prevalence and risk factors of infertility as well as care seeking behavior among infertile couples in a random sample of a local population. METHODS: A questionnaire was distributed to 1,784 women between 25 and 44 years of age working at or living close to a copper smelter, and to women living further away from the smelter. The results were analyzed with a logistic regression. RESULTS: No environmental effects on infertility rates among couples living near the smelter were found. The prevalence of infertility, defined as having experienced a period of inability to conceive within 12 months of regular intercourse without contraception at some point in life, was the same between the neighbors and the reference population. The prevalence of primary and secondary infertility was 6% and 3%, respectively. Infertile women were characterized by having a significantly shorter education, OR 1.8 (CI 1.2-2.7), compared to women who had not experienced any fertility problems. Risk estimates for not seeking health care when having a low socio-economic status was OR 2.1 (CI 1.0-4.4) compared to those with a higher socio-economic status. CONCLUSION: No environmental effects on infertility could be demonstrated. Infertile women were characterized by having a shorter education compared to the non infertile, and women with lower socio-economic status were less prone to seek help.

Adult↗

Photolysis of the carbon monoxide complex of myoglobin: nanosecond time-resolved crystallography.

The biological activity of macromolecules is accompanied by rapid structural changes. The photosensitivity of the carbon monoxide complex of myoglobin was used at the European Synchrotron Radiation Facility to obtain pulsed, Laue x-ray diffraction data with nanosecond time resolution during the process of heme and protein relaxation after carbon monoxide photodissociation and during rebinding. These time-resolved experiments reveal the structures of myoglobin photoproducts, provide a structural foundation to spectroscopic results and molecular dynamics calculations, and demonstrate that time-resolved macromolecular crystallography can elucidate the structural bases of biochemical mechanisms on the nanosecond time scale.

Carbon Monoxide↗

Feasibility and Realization of Single-Pulse Laue Diffraction on Macromolecular Crystals at ESRF.

Laue diffraction patterns with an exposure time of ca 60 ps have been acquired at the European Synchrotron Radiation Facility (ESRF) on protein crystals by using the single-bunch mode of the storage ring. A 10 ns laser pulse initiating photodissociation was synchronized with the X-ray pulse. The potential for a quantitative detection of conformational changes in proteins on the nanosecond timescale with this technique is demonstrated using the example of carbonmonoxymyoglobin, from simulations and real data. The instrumental aspects of the experiment (highly intense X-ray beam, fast shutter system, Laue camera, detector, laser apparatus and synchronization technique) are emphasized.

Journal Article↗

The structure of the Escherichia coli EF-Tu.EF-Ts complex at 2.5 A resolution.

The crystal structure of the EF-Tu.EF-Ts complex from Escherichia coli has been determined to a resolution of 2.5 A. The complex contains two subunits of each of the elongation factors. The two EF-Ts molecules form a tight dimer, but there is little contact between the two EF-Tu molecules. The interaction of EF-Ts with EF-Tu results principally in the disruption of the Mg2+ ion binding site, thereby reducing the affinity of EF-Tu for guanine nucleotides.

Amino Acid Sequence↗

Congenital malformations in the vicinity of a smelter in Northern Sweden, 1973-1990.

The objective was to evaluate the rates of congenital malformation in children born in a population living around a smelter and to employees at the smelter, in a community in northern Sweden. By means of record linkage of the birth register and various registers of congenital malformations, a retrospective study of a birth cohort according to place of parental residence and employment was carried out to assess rates of congenital malformation occurring between 1973-1990. Neither a general, nor specific, significantly increased risk of congenital malformation was seen in the 2724 children born to women living close to the smelter or to employees of the smelter compared with the 15191 children in the reference population. No increased risk could be ascertained although there are reservations concerning the small sample size of the study group.

Case-Control Studies↗

Cancer incidence for children born in a smelting community.

The Rönnskär smelter in Skellefteå, Sweden, produces significant environmental pollutants, such as lead, arsenic, copper, cadmium and sulphur dioxide. The purpose of the present study was to determine whether children born to women living near the smelter during pregnancy had an increased risk of childhood cancer. The study group consisted of children born between 1961 and 1990 in the municipality of Skellefteå and parish of Holmsund. Through linkage to the Swedish Cancer Registry cancer diagnoses in the study group were obtained and compared with the expected ones based on the national incidence rates. Thirteen cases of childhood cancer were identified among children born in the vicinity of the smelter against 6.7 expected (SIR 195, 95%CI 88-300). Among distant born the observed number of cases (n = 42) was similar to that expected (n = 41.8).

Adolescent↗

Perinatal outcome among the offspring of employees and people living around a Swedish smelter.

OBJECTIVE: The purpose of this study was to determine if emissions from a smelter affect the birthweight of offspring and increase the risk of prenatal death. METHODS: A historical cohort was formed from registers of birth and employees from 1961 to 1991. Comparisons of birthweight and perinatal deaths between children born to smelter employees or children born to women living around the smelter and those of a reference population were performed. To study reproductive effects before 1961, a case-referent study was performed with cases of stillbirths from 1937-1961 in one parish. RESULTS: No differences in birthweight were found between the children born to employees or to people living near the smelter and those in the reference group. An increased risk of perinatal death among children born to women in the exposed group was seen during the period 1966-1970. However, for the rest of the observation period, 1961-1990, this higher risk was not apparent. CONCLUSIONS: For the last 20 years emissions from the smelter had not affected the birthweight and the risk of perinatal death among the offspring of parents living near the smelter or those employed at the smelter.

Birth Weight↗

A prospective comparative study of clinical and pathological characteristics in Icelandic and Danish patients with gastric ulcer, duodenal ulcer, and X-ray negative dyspepsia. II. Histological results.

The occurrence of gastritis in antral and body mucosa is compared in an Icelandic and a Danish group of patients with gastric ulcer, duodenal ulcer, and X-ray negative dyspepsia. In all 93 Icelandic and 88 Danish patients were examined. All signs of antral gastritis were more frequent in Icelandic than in Danish patients, but only the incidence of superficial inflammation and decreased mucus content in surface and crypt epithelium differed significantly. In body mucosa pseudopyloric metaplasia was more frequent in Iceland and occurred equally freqeuntly in all three diseases. A statistically significant correlation was found between macroscopic gastritis and occurrence of antral superficial inflammation and between smoking and superficial inflammation and decreased mucus content in the pyloric biopsy specimen. The presence of histological gastritis was not correlated to the intake of alcohol and salicylic acid, nor to the presence of pain at the time of investigation.

Adult↗

A prospective comparative study of clinical and histological characteristics in Icelandic and Danish patients with gastric ulcer, duodenal ulcer, and X-ray negative dyspepsia. I. Design and clinical features.

Iceland (IS) and Denmark (DK) are ethnically, culturally, and economically closely related Nordic countries, but gastric cancer is much more frequent in Iceland, and other differences in the occurrence rates of gastric diseases are also suspected. Therefore a cooperative study was initiated comparing Icelandic and Danish patients with gastric ulcer (GU), duodenal ulcer (DU), and X-ray negative dyspepsia (XND) as regards clinical features, external factors of possible importance for gastritis and cancer, gastroscopic appearance, and histological gastric mucosal changes. The project lasted one year and comprised 93 Icelandic and 88 Danish patients. A large number of comparisons showed a high degree of similarity between Icelandic and Danish patients. Significant differences were found in tobacco consumption (DK greater than IS), duration of symptoms in XND (IS greater than DK), whereas the positon ratio of GU (IS less than DK) and acetylsalicylic acid consumption (DK greater than IS) showed non-significant trends. Significant difference was found between the occurrence of diffuse macroscopic changes of the gastric mucosa (IS greater than DK), which corresponds to the histological differences to be described in a subsequent article.

Adolescent↗