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Biomedical subjects

A Ostberg

Publications and source records attributed to A Ostberg.

12 recordsLinked to original sources
PubMed2005

Use of low-dose mitozantrone to treat aggressive multiple sclerosis: a single-centre open-label study using patient self-assessment and clinical measures of multiple sclerosis status.

BACKGROUND: There is significant evidence supporting the use of mitozantrone in the treatment of multiple sclerosis (MS) but few data on the subtypes of MS that respond or which measures of disease status are most useful. AIMS: To assess the efficacy of low-dose (5 mg/m2 3 monthly) mitozantrone using patient self-assessment questionnaire (SAQ), expanded disability status score (EDSS), multiple sclerosis functional composite score (MSFC), and the fatigue severity scale (FSS). Then, to compare the responses of a subgroup of relapsing remitting MS (RRMS) and secondary progressive MS (SPMS) patients to treatment, and to assess which measures of MS disease status are the most useful in a study of this type. METHOD: Thirty-one patients with definite (McDonald criteria) active MS were commenced on mitozantrone 5 mg/m2 every 3 months. EDSS, MSFC and FSS data collected before treatment and after 12 months were analysed. The SAQ was administered after at least 12 months of therapy. RESULTS: RRMS patients showed significantly more response to mitozantrone than SPMS patients in terms of MSFC (P = 0.02) and SAQ (P = 0.01). CONCLUSIONS: Low-dose mitozantrone was well tolerated and useful in active RRMS in the short term; however, mitozantrone did not display any useful activity in SPMS patients over this time interval or at the mitozantrone dose used. Patient perception of treatment is a worthwhile outcome measure and the MSFC is the most useful objective measure of MS status change in this type of study.

Adult↗
PubMed2001

Posterior capsule opacification with AcrySof and poly(methyl methacrylate) intraocular lenses. Comparative study with a 3-year follow-up.

PURPOSE: To evaluate whether reports of reduced posterior capsule opacification (PCO) rates with AcrySof intraocular lenses (IOLs) are applicable to a mixed group of cataract patients in everyday surgical practice. SETTING: Department of Ophthalmology, Kärnsjukhuset, Skövde, Sweden. METHODS: A retrospective study comparing a study group receiving an AcrySof IOL (n = 145) and a group receiving a poly(methyl methacrylate) (PMMA) IOL (n = 153) was performed. The follow-up was 3 years in both groups. The performance of a neodymium:YAG laser capsulotomy was used as the end point for clinically significant PCO. RESULTS: Nine capsulotomies (6.2%) were performed in the AcrySof group and 34 (22.2%) in the PMMA group. The difference in the capsulotomy rate between the 2 groups was highly significant (P <.001). The relative risk was 3.6 times higher in the PMMA group. CONCLUSIONS: There was a significant difference in the frequency of capsulotomy between AcrySof and PMMA IOLs in a mixed group of cataract patients in everyday clinical practice. This finding indicates the importance of the IOL type in PCO formation.

Acrylic Resins↗
PubMed1982

Competitive reinnervation of the rat superior cervical ganglion by foreign nerves.

The efficacy of foreign nerves to form synapses was studied morphologically and physiologically in the superior cervical ganglion of the rat. The denervated ganglion was anastomosed to the central stump of either the vagus, the hypoglossal or both nerves together. The degree of reinnervation was assessed two to ten months later. We measured the strength of contraction of the nictitating membrane after each type of operation and compared this to the number, type and distribution of synapses in the same ganglion. Both the vagus and hypoglossal nerves preferentially reinnervated a population of neurones that are situated in the cranial pole of the superior cervical ganglion and supply the nictitating membrane. When both nerves were connected to the ganglion only the vagus nerve could be shown to reinnervate it, and no reinnervation by the hypoglossal nerve was detected. However, in this experiment neither foreign nerve did as well in competition as each did alone and the overall result was reduced functional efficiency. We conclude that not all sympathetic neurones are equivalent and that, just like sympathetic afferents, the foreign nerves are capable of selectively reinnervating preferred target cells.

Animals↗
PubMed1980

Timolol versus pilocarpine separately or combined with acetazolamide-effects on intraocular pressure.

Fifty-eight patients with intraocular hypertension or primary open angle glaucoma participated in a double masked randomized study. Timolol in concentrations 0.25% and 0.5% was compared with 1, 2, or 4% pilocarpine Acetazolamide (250 mg x 3) was added if intraocular pressure (IOP) was uncontrolled with the highest concentrations tested. No statistical difference was found in hypotensive effect between pilocarpine and timolol neither on ocular hypertensions nor glaucomas. The additive hypotensive effect of acetazolamide was the same for both substances. Once a day by administration of timolol was sufficient in 17 of 20 cases controlled merely by topical administration.

Acetazolamide↗
PubMed1979

Ultrastructural study of degeneration and regeneration in the amphibian tectum.

The processes of degeneration and reinnervation in the optic tectum of Xenopus laevis have been detailed by quantitative ultrastructural analysis. The tecta were denervated either permanently, by removing the contralateral eye, or temporarily, by cutting the optic tract. After denervation the total number of synapses decreases rapidly within 4 days of a stable level of about 40% of the original number. Vacated postsynaptic sites are subsequently removed by phagocytosis. When regenerating axons arrive in the tectum they make synaptic contact by inducing new postsynaptic membrane specializations. The ultrastructural sequence of reinnervation by optic axons resembles initial synaptogenesis.

Animals↗
PubMed1979

The relationship between retinal and tectal growth in larval Xenopus: implications for the development of the retino-tectal projection.

The modes of retinal and tectal histogenesis, as well as the patterns of terminal distribution of optic axons in larval Xenopus were studied, using anatomical techniques. We show that the retina grows by adding strips of cells at its ciliary margin. The pattern of retinal growth is asymmetrical along the dorso-ventral axis of the retina. On the other hand, the tectum grows by adding newly formed cells caudo-medially. The most rapid tectal growth takes place between stages 50 and 53, and thereafter only a small proportion of cells are added near the midline of the caudal tectum. Despite such incongruent modes of retinal and tectal growth, retinotopic order is maintained throughout larval life. We present here further evidence supporting the idea that connexions between the arrays of retinal and tectal cells shift progressively caudo-medially on the tectum during the period of growth. When the temporal pole of the retina is destroyed at various developmental stages, the density of degenerating synapses is always highest in the rostral pole of the tectum. Moreover, optic terminals stemming from the central retina spread caudally, invading newly maturing regions of the tectum. Quantitative analysis of the terminal distributions of optic axons suggest that orderly shifts in synaptic contacts between optic axons and tectal dendrites take place in the course of development. Ultrastructural observations on the maturing tectal neuropil are consistent with this view.

Animals↗
PubMed1971

Action of 6-hydroxydopamine on lamb sympathetic ganglia, vas deferens and adrenal medulla: a combined histochemical, ultrastructural and biochemical comparison with the effects of reserpine.

1. The effects of a single dose of 6-hydroxydopamine (6-OHDA) compared with those of chronic reserpine treatment were studied in lamb sympathetic neurones and adrenal medulla by a combination of fluorescence histochemistry, electron microscopy and radiochemical assay.2. In sympathetic ganglia, 6-OHDA produced a rise in noradrenaline concentration within 24 h, and falls in tyrosine hydroxylase and monoamine oxidase activities, whereas reserpine caused a fall in noradrenaline, a rise in tyrosine hydroxylase activity and no change in monoamine oxidase activity. The fluorescence of intra- and postganglionic axons increased greatly within 24 h of 6-OHDA, and there was a corresponding accumulation of large dense-core vesicles within many axons whose neurotubules were disrupted. The changes were almost reversed after 3 weeks.3. In the vas deferens, the concentration of noradrenaline and tyrosine hydroxylase and monoamine oxidase activities had all fallen 24 h after 6-OHDA treatment and had started to recover 3 weeks later. In the adrenal medulla, 6-OHDA did not alter NA concentrations but increased tyrosine hydroxylase activity whereas reserpine depleted noradrenaline and increased tyrosine hydroxylase activity.4. The changes produced in sympathetic ganglia by 6-OHDA may be due both to a direct action on the axoplasmic transport of noradrenaline containing vesicles and indirectly to the reaction of the neurones to loss of the integrity of their axons.

Adrenal Medulla↗
PubMed1969

Distribution of granular vesicles in normal and constricted sympathetic neurones.

1. A quantitative analysis has been made of the characteristics of granular vesicles in different parts of normal and ligated post-ganglionic sympathetic neurones supplying the cat spleen. The least diameter of the vesicle membrane and its electron-dense core was measured from electron micrographs with an automated particle size analyser.2. Vesicles of average diameter 443 A, with and without electron-dense cores (192 A), were concentrated in the axon terminals of the spleen, whereas in the cell bodies in the coeliac ganglion and their axons there were only a few large vesicles (787 A) with large granules (562 A).3. Ligation of the splenic nerves for 24 hr resulted in an accumulation proximal to the constriction of granular vesicles significantly larger (688 A) and more completely granulated (478 A) than those in the terminals.4. Reserpine reduced the number of vesicles with granular cores without discrimination between the two populations.5. Since the distribution of noradrenaline in sympathetic neurones can be correlated with the presence of large as well as small granular vesicles, it is suggested that the larger, more granular type found mainly proximally in the neurone is in transit from its perikaryal site of synthesis to the axon terminals, where it is transformed into the smaller synaptic vesicles.

Animals↗