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Biomedical subjects

L Nordstrom

Publications and source records attributed to L Nordstrom.

9 recordsLinked to original sources
PubMed2006

Association between lactate in vaginal fluid and time to spontaneous onset of labour for women with suspected prelabour rupture of the membranes.

OBJECTIVES: To assess whether lactate determination in vaginal fluid is associated with, and can predict, onset of labour for women with suspected prelabour rupture of the membranes (PROM). DESIGN: Prospective observational study. SETTING: Labour ward at Soder Hospital, Stockholm, Sweden. POPULATION: Women with suspected PROM after 34 weeks of gestation, who later had spontaneous onset of labour (n = 179). METHODS: All women underwent a speculum examination and a test for determining lactate concentration in vaginal fluid. We used logistic regression to estimate the association between lactate concentration in vaginal fluid and time to onset of labour. MAIN OUTCOME MEASURES: Time from examination to onset of labour (cervix > or =4 cm), within 24 hours and 48 hours. RESULTS: The median time interval between examination and spontaneous onset of labour was 8.4 hours for women with 'high' lactate (> or =4.5 mmol/l) and 54 hours for those with 'low' lactate concentrations (<4.5 mmol/l). Among 86 women with high lactate concentrations, 76 (88%) had started labour within 24 hours compared with 20 of 93 (22%) women with low lactate concentrations (OR 27.7, 95% CI 12.2-63.3). After checking for the effect of visible amniotic fluid, the corresponding odds were still substantially increased (OR 13.5, 95% CI 5.3-34.3). CONCLUSIONS: High lactate concentration (> or =4.5 mmol/l) in vaginal fluid can be used to predict whether a woman with suspected PROM will commence spontaneous onset of labour within 24 or 48 hours.

Adult↗
PubMed2000

Non-collinear states in magnetic sensors

Certain materials have an electrical conductivity that is extremely sensitive to an applied magnetic field; this phenomenon, termed 'giant magnetoresistance', can be used in sensor applications. Typically, such a device comprises several ferromagnetic layers, separated by non-magnetic spacer layer(s)--a so-called 'super-lattice' geometry. In the absence of a magnetic field, the ferromagnetic layers may be magnetized in opposite directions by interlayer exchange coupling, while an applied external magnetic field causes the magnetization directions to become parallel. Because the resistivity depends on the magnetization direction, an applied field that changes the magnetic configuration may be detected simply by measuring the change in resistance. In order to detect weak fields, the energy difference between different magnetization directions should be small; this is usually achieved by using many non-magnetic atomic spacer layers. Here we show, using first-principles theory, that materials combinations such as Fe/V/Co multilayers can produce a non-collinear magnetic state in which the magnetization direction between Fe and Co layers differs by about 90 degrees. This state is energetically almost degenerate with the collinear magnetic states, even though the number of non-magnetic vanadium spacer layers is quite small.

Journal Article↗
PubMed1998

The reliability of catheter-tip transducers for the measurement of intrauterine pressure in the third stage of labour.

In order to assess the reliability of intrauterine pressure measurements in the third stage of labour, catheter-tip transducers were used in 20 women randomly allocated into two groups of 10. In each case in the first group two catheters were tied together and introduced transcervically into the uterine cavity after delivery of the placenta. In each case in the second group two catheters were inserted independently into the same uterine cavity. The active and cumulative active pressures recorded from the pairs of catheters within each uterine cavity were compared. Comparison of individual active pressure readings from separate transducers revealed good agreement whether the catheters were tied together or were separate. Cumulative active pressure was very similar when assessed by each catheter in the same uterus. Intrauterine catheter-tip transducers can be used reliably to measure uterine activity in the third stage of labour although there may be minor contraction by contraction differences in recordings of individual active pressures.

Catheterization↗
PubMed1998

Validation of a laboratory method of measuring postpartum blood loss.

Laboratory methods give more accurate measurement of blood loss in the postpartum period than visual estimation. In order to evaluate a laboratory method used to quantify blood loss postpartum, blood lost at gynecological operations was collected in a measuring bottle. The measured amount of blood (50-1,000 ml) was then poured onto absorbent paper towels and sanitary pads, in order to mimic conditions when measuring blood loss in clinical trials in the postpartum period. The amount of blood absorbed onto the absorbent paper and sanitary pads was measured by a rapid method of automatic extraction and photometric measurement of alkaline hematin. The study shows that the method provides a reliable and accurate means of measuring blood loss. The error in each case was less than 10% with an intraclass correlation coefficient of almost 1.

Analysis of Variance↗
PubMed1991

A 25-year experience with 519 anterior colporrhaphy procedures.

A 25-year experience with 519 anterior colporrhaphies was reviewed to assess the results in treating genuine and mixed stress urinary incontinence, the incidence of new urinary incontinence following prolapse surgery, the incidence of new detrusor instability after incontinence and prolapse surgery, and the morbidity associated with anterior colporrhaphy. The cure rate in treating genuine stress incontinence in 194 patients was increased from 75 to 94% when a Kelly-Kennedy-type technique was modified to include a vaginal retropubic urethropexy. The surgical cure in treating mixed incontinence was unsatisfactory (64%) in unselected cases but good (84%) in selected cases. Previous incontinence surgery, especially more than one procedure, significantly reduced the cure rate for genuine stress incontinence. The incidence of new incontinence after prolapse surgery in one subgroup of patients was 11%, indicating the need for measures to minimize this possibility at prolapse surgery. The incidence of new detrusor instability after surgery was 6% (higher after incontinence surgery than after prolapse surgery). The incidence of significant morbidity, excluding incontinence, was minimal (1%) among the 519 anterior colporrhaphies.

Adult↗
PubMed1988

The fascia lata sling procedure for treating recurrent genuine stress incontinence of urine.

The fascia lata sling procedure has been used over the past 22 years in our unit for treating recurrent urinary stress incontinence when irreparably poor local support tissues were suspected. Sixty-nine patients had undergone one previous operation to correct urinary stress incontinence. One hundred one patients had two or more previous operations. The cure rate for the condition of genuine stress incontinence has been 100% in the last 148 cases and 98.2% overall. However, the cure rate for the symptom of urinary stress incontinence was 92.4%. There were only three sling failures in the entire series, occurring in the first 22 cases. Ten other patients had urinary incontinence with stress because of motor urge incontinence. The most troublesome postoperative problem has been delayed voiding.

Adult↗
PubMed1988

Intraurethral-intravesical cough-pressure spike differences in 267 patients surgically cured of genuine stress incontinence of urine.

Cough-pressure spike differences between the urethra and bladder were compared before and after surgery that cured genuine stress incontinence in 267 women. In 97.4% of 151 patients cured by a fascia lata sling procedure, the urethralvesical cough-pressure transmission ratio was greater than 100%, and in no case was it less than 100%. In 46.6% of 116 patients cured by anterior colporrhaphy, the cough-pressure transmission ratio was greater than 100%, and in 20.7% of the 116 patients, the transmission ratio was less than 100%. The 24 women in the latter group were cured by a sufficient increase in resting intraurethral pressure (to augment the maximal intraurethral closure pressure with stress) to maintain continence with increased intra-abdominal pressure. We believe that urethral kinking at the instant of increased intra-abdominal pressure with stress produced the greater than 100% cough-pressure transmission ratio seen in 201 (75.3%) of the 267 patients cured of genuine stress incontinence.

Cough↗
PubMed1976

Chest pain as a predictor of coronary artery disease in patients with obstructive aortic valve disease.

To clarify the association between chest pain and significant coronary artery disease in patients who have aortic valve disease, 76 consecutive candidates for aortic valve replacement were evaluated prospectively with use of a historical questionnaire and coronary arteriography. Of the 76 patients, 19 (25 percent) had no chest pain, 21 (28 percent) had chest pain that was not typical of angina pectoris and 36 (47 percent) had chest pain typical of anigina pectoris. In 18 of 19 patients the absence of chest pain correlated with the absence of coronary artery disease. The single patient without chest pain who had coronary artery disease had evidence of an inferior myocardial infarction in the electrocardiogram. Thus, absence of chest pain and the absence of electrocardiographic evidence of infarction predicted the absence of coronary disease in all cases. The presence of chest pain did not predict the presence of coronary artery disease, but the more typical the pain of angina pectoris the more likely were patients to have significant coronary artery disease. Of the 21 patients with atypical chest pain, 6 (29 percent) had coronary artery disease, but of the 36 patients with typical angina pectoris 23 (64 percent) had significant coronary artery disease. In addition, when patients with chest pain not typical of angina pectoris also had coronary artery disease, the diseased vessels usually supplied smaller areas of the left ventricle than when the pain was typical of angina pectoris. In 21 of 23 patients (91 percent) with typical angina pectoris and significant coronary artery disease, lesions were present in the left coronary artery. There was no systolic pressure gradient across the aortic valve that excluded the presence of coronary artery disease, although all patients with a calculated aortic valve area of less than 0.4 cm2 were free of coronary artery disease. Patients with severe left ventricular dysfunction were more likely to have normal coronary arteries.

Adult↗