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Biomedical subjects

J Larsen

Publications and source records attributed to J Larsen.

At least 163 records · Page 9Linked to original sources
PubMed1985

Induction of labor. A double-blind randomized controlled study of prostaglandin E2 vaginal suppositories compared with intranasal oxytocin and with sequential treatment.

In a double-blind randomized controlled study of 300 women, 150 primiparas and 150 multiparas, induction of labor by means of vaginal suppositories containing 3 mg prostaglandin E2 (PGE2) was compared with the conventional method of intranasal oxytocin and with a combined method of 3 mg PGE2 vaginal suppositories alternating with intranasal oxytocin. In the PGE2 group the intensity of delivery was significantly greater than in the oxytocin group, among both primiparas and multiparas and among the patients with ripe and unripe cervix. The efficiency of the combined treatment could no be evaluated because of the high intensity of delivery during the first 24 hours. There were no maternal side effects, and no significant difference in the frequencies of failed induction and cesarean section.

Administration, Intranasal↗
PubMed1985

Quantitative vitreous fluorophotometry applying a mathematical model of the eye.

A slit-lamp fluorophotometric method is presented that permits calculation of a blood-retinal barrier permeability to fluorescein (P) and a diffusion coefficient for fluorescein in the vitreous body (D). The calculations are performed by relating the time course of the free--not protein bound--fluorescein concentration in the bloodstream with the fluorescein concentration profile in the vitreous body. The combination is performed automatically on a computer by applying a simplified mathematical model of the eye. P refers to the area of the barrier of the model eye. In a group of six normal persons, the mean P was (1.1 +/- 0.4) X 10(-7) cm/sec (mean +/- SD), while in six diabetic patients with background retinopathy and macular edema the mean P was (7.1 +/- 3.8 ) X 10(-7) cm/sec. The mean D was (7.4 +/- 3.4) X 10(-6) cm2/sec in the normal group and (9.6 +/- 2.0) X 10(-6) cm2/sec in diabetic patients, corresponding as a first approximation to free diffusion in water. Model calculations show that knowing the fluorescein concentration in the bloodstream is considerably significant for the calculation of the permeability, contributing factors up to 50%. For the low-permeation situation, subtraction of the preinjection scan contributes a factor of 50% for both permeability and diffusion coefficient. The exact placement in the vitreous body of the concentration profile, by applying a formalism that transforms slit-lamp movement to intraocular distance, contributes a factor of 20% on the diffusion coefficient. The permeability obtained with the model can be calculated as the ratio between area of vitreous and plasma fluorescein concentration curves within 20%. Active transport of fluorescein across the blood-retinal barrier in the direction of vitreous to blood does not seem to be significant within the first 2 hr after fluorescein injection.

Blood Physiological Phenomena↗
PubMed1984

Photometric oculometry. I. An analysis of the optical principles in slit-lamp fluorophotometry.

The optical principles of slit-lamp fluorophotometry are analysed by aid of a mathematical model of the optical system. The analysis forms the theoretical basis for a slit-lamp technique called photometric oculometry, which makes possible an estimation of intraocular axial distances and axial length. The technique is based on a calculation--by aid of a mathematical model of the eye--of the ratio between intraocular movement of the slit-lamp focal plane and corresponding movement of the slit-lamp. Intraocular axial distances can be calculated by aid of this ratio and a direct measurement of the slit-lamp movement when the focal plane is moved in the optical axis from retina to cornea. These items are prerequisites for a quantitative determination of the blood-retinal barrier permeability to fluorescein during vitreous fluorophotometry.

Eye↗
PubMed1984

Photometric oculometry. II. Measurement of axial ocular distances with slit-lamp microscopy. Clinical evaluation, and comparison with ultrasonography.

Photometric oculometry is a slit-lamp technique, which makes possible an estimation of intraocular axial distances and axial length. The technique is based on a transformation of a sagittal slit-lamp movement into intraocular axial distances when the slit-lamp focal plane is moved in the optical axis from retina to cornea. Determination of the axial length in 50 eyes (refractive range +4.75 to -5.25 D) showed that the axial length varied from 21.9 mm in hypermetropic eyes to 26.0 mm in myopic eyes, with the emmetropic eyes being approximately 24 mm. A comparison of intraocular axial distances determined by photometric oculometry and by ultrasonography on a small series of eyes showed no significant differences between the axial length, the length of the vitreous body, and the lens thickness, whereas a significant difference between the anterior chamber depth was observed (photometry giving slightly larger values than ultrasound).

Adult↗
PubMed1983

Leadership, nurses and the 1980s.

The author examines some of the reasons for the leadership problems in nursing by focusing on the question of 'why leaders are not leading'. Drawing on James MacGregor Burns' general theory of political leadership, the article examines issues of motives, resources, followers and the structure of nursing today.

Canada↗
PubMed1983

Variations in blood viscosity in patients with acute cardiogenic pulmonary oedema treated with frusemide.

In 10 patients with acute cardiogenic pulmonary oedema, treatment with large doses of intravenous frusemide (mean dose 156 mg) induced no signs of haemoconcentration. On the contrary, during an observation period of 2 h after start of treatment we registered a significant reduction of mean blood viscosity and mean haematocrit, indicating haemodilution. All the patients also received a basic treatment of intravenous pethidine and nasal oxygen and the conclusion is therefore that large doses of intravenous frusemide in treatment of acute cardiogenic pulmonary oedema can be given without risk of haemoconcentration when combined with intravenous pethidine and nasal oxygen.

Acute Disease↗
PubMed1983

Dipalmitoylphosphatidylcholine in amniotic fluid quantified by fast-atom-bombardment mass spectrometry.

Dipalmitoylphosphatidylcholine (DPC) is quantified by taking advantage of stable-isotope-labeled d9-DPC as internal standard. Use of a mass spectrometer to measure the ratio of d9/d0 makes this procedure a quantitative one. d9-DPC was synthesized by refluxing dipalmitoylethanolamine with d3-methyl iodide in methanol in the presence of sodium bicarbonate for 26 h. The yield of d9-phosphatidylcholine (d9-lecithin) was 89% after column-chromatographic purification. Fast atom bombardment was used to desorb the preformed phosphatidylcholine ions in a mass spectrometer of Nier-Johnson geometry. In our assessment of accuracy and precision of this technique, we found a correlation coefficient of 0.9994 between signal and sample concentration. The method was less precise when the total d0- plus d9-DPC was less than 0.2 micrograms or when the ratio of d0- to d9-lecithin exceeded 100. The within-run CV was about 1.0%. The amount of DPC in amniotic fluid samples assessed by mass spectrometry was compared with results for total phosphatidylcholine quantified by thin-layer chromatography. The fate of DPC in various laboratory manipulations was also studied.

Amniotic Fluid↗
PubMed1982

Reliability of the WAIS-R with a mixed patient sample.

Reliability of the WAIS-R for a mixed sample of psychiatric and neurological patients was determined. Split-half reliabilities and standard errors of measurement were computed for all subtests (exept Digit Span and Digit Symbol) and the Verbal, Performance, and Full Scale IQs. Only the Arithmetic subtest had a reliability estimate which was significantly lower than that of the 35-44-yr.-old standardization group. All other reliabilities and standard errors of measurement approximated those reported for the normative group. It was concluded that the WAIS-R is a reliable instrument for evaluating patients in a clinical setting.

Adult↗