PubMed Health⌕ Search

Biomedical subjects

B Tengroth

Publications and source records attributed to B Tengroth.

At least 55 records · Page 3Linked to original sources
PubMed1985

A comparative analysis of the collagen type and distribution in the trabecular meshwork, sclera, lamina cribrosa and the optic nerve in the human eye.

A theory has been advanced (Tengroth et al 1984) that one common factor might be involved in the pathogenesis of chronic open angle glaucoma. The mechanical properties of the collagen could be one such factor. To characterize the collagen composition of the critical structures in cases with chronic open angle glaucoma i.e. the trabecular meshwork and the lamina cribrosa in the human eye, the following investigations were performed. Using immunoperoxidase technique and type specific antibodies to the genetically distinct collagen types I, III, IV and procollagen I along with the major non collagen proteins in the extracellular matrix laminin and fibronectin a light microscopic study was undertaken on the trabecular meshwork, cornea, sclera, lamina cribrosa and the optic nerve of the human eye. Furthermore biochemical analysis was performed on the collagen associated aminoacids hydroxyproline (Hyp), hydroxylysine (Hyl) and prolin (Pro) from microdissected samples of trabecular meshwork, sclera, lamina cribrosa and optic nerve. Both the immunohistological and the biochemical findings suggested similarities in the collagen composition between the trabecular meshwork and the lamina cribrosa. The immunohistochemical findings showed stronger staining of type III and IV in the trabecular meshwork and lamina cribrosa as compared to sclera or cornea while the opposite was true for type I and procollagen I. Fibronectin and laminin were present in both the trabecular meshwork and lamina cribrosa. These findings were in agreement with the amino acid analysis when the Hyp/Hyl ratio was calculated for each sample.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1984

Age and sex distribution of some retinal macular diseases: senile and presenile macular degeneration and central serous retinitis.

The age and sex distribution of senile macular degeneration (SMD) was investigated at the Low Vision Clinic in Stockholm. SMD increased with age and was found to be more common among women than men. This difference was not due to the fact that women live longer than men or related to women consulting ophthalmologists more often than men because of visual handicap. The age and sex distribution of presenile macular degeneration ( PSMD ) and central serous retinitis (CSR) was investigated at the Department of Ophthalmology of Falun Hospital. Also PSMD increased with age and was found to be more common among women than men, even if the sex difference was not as clear as for SMD. CSR was found to be more frequent at younger ages and, contrary to SMD and PSMD , more common among men. The reasons for these sex differences in frequencies of SMD, PSMD and CSR are not known.

Adult↗
PubMed1984

Changes in the content and composition of collagen in the glaucomatous eye--basis for a new hypothesis for the genesis of chronic open angle glaucoma--a preliminary report.

The pressure theory is still predominant in explaining the pathophysiology of the chronic open angle glaucoma. An insufficient drainage system resulting in an increased intraocular pressure is the basis for this theory. The pressure will exert an effect upon the optic disc which either directly on the nerve fibres or indirectly via the vascular system will result in a characteristic optic atrophy. The collagen fibres, both in the trabecular meshwork of the anterior chamber and in the lamina cribrosa of the optic disc, form a mesh through which the aqueous humour and the nerve fibres, respectively, pass through the wall of the eye. A hypothesis explaining the pathophysiology of this disease, and based on the assumption that there is a primary change in the collagen molecules, resulting in a weaker structure than normal both in the trabeculae and in the laminae, is forwarded. The structures analysed for the content of hydroxyproline, hydroxylysine and proline were the trabecular meshwork, the sclera and the lamina cribrosa. Three categories of autopsy eyes were studied, i.e. normal eyes, glaucomatous eyes, and eyes under a suspicion of glaucoma. In the normal eyes, the collagen composition in the trabecular meshwork was different from that in the sclera and the lamina cribrosa. There is also a difference in the composition between the sclera and the lamina cribrosa. In glaucoma, the content and/or the composition of the collagen molecules in the lamina were significantly changed. In the eyes under suspicion of glaucoma the same changes as in the glaucomatous eyes could be demonstrated. However, 5 of the 7 eyes in this category had no demonstrable nerve atrophy. The findings suggest that the change in collagen pattern is primary. This study has not demonstrated which types of collagen are present or the physical properties of this collagen. Further tests to demonstrate the different types of collagen and their rigidity are planned.

Aged↗
PubMed1980

The effect of melperon on ocular readaptation time, as assessed by a new recording technique.

A new simplified technique recording readaptation time after photo stress, RAT, is described. The psychometric properties in terms of internal consistency and retest reliability were tested, and the effect on RAT after intake of melperon at two different dose levels was investigated and correlated to blood plasma levels. The results show that there was a satisfactory consistency of RAT at each occasion but stability over a 1 month period could not be demonstrated. Significantly dose-dependent changes were recorded after intake of melperon but the prolongation of RAT was not significantly correlated to blood plasma levels.

Adaptation, Ocular↗
PubMed1979

The effect of oxazepam on ocular readaptation time.

The readaptation time (RAT) is the interval during which a person exposed to a bright intense light flash cannot perceive a given target. In this study the target used was an optokinetic pattern and the elicited nystagmus (OKN) was registered with electrooculography (EOG), thus giving an objective registration of RAT. Oxazepam in therapeutic doses was given to five healthy subjects and the RAT and serum concentrations of the drug were registered simultaneously at different time intervals. An almost parallel increase of RAT and serum concentration of oxazepam was recorded. This suggests that RAT reflects the depressant effect on the CNS of this drug and it may be used as an objective method of following the clinical effect of a depressant drug as a function of time after intake.

Adaptation, Ocular↗
PubMed1977

Readaptation time after photo stress. Alcohol-induced acute and post-alcohol 'hangover' changes in ocular readaptation time.

The effect of alcohol intake on readaptation time (RAT) after photo stress is studied. Ten healthy subjects were given 0.72 g alcohol per kg body weight to be consumed within 20 min. The tests were made during a total period of 11-12 h. The findings demonstrate that moderate blood alcohol concentrations induce definite changes in RAT. An average RAT-prolongation of 60-70% was seen during the acute phase of intoxication. RAT-prolongation ended before the blood alcohol concentration had reached zero, but did not have the same downward slope. Following a period of reduction, a new prolongation of RAT was observed. The lack of congruence between the RAT-curve and the blood alcohol curve in the acute phase of intoxication and the post-alcohol increase are discussed. It is concluded that the alcohol-induced RAT-changes probably are CNS-effects and that the equipment used constitutes a sensitive method of estimating these effects.

Adaptation, Ocular↗
PubMed1977

Retinoblastoma treated with a 60CO applicator.

The 60Co applicator for treatment of retinoblastoma, described in 1963, has the advantage of exact local positioning. It is suitable in cases with solitary small tumours. The complications and the results of treatment in 20 patients followed up for at least 2 years are reported and discussed.

Cataract↗
PubMed1977

Welding light.

Two types of electric welding, welding with gas-shielded arcs and welding with coated electrodes, are considered in this paper. The possible radiation injuries to the eye are described, and the measures for protection discussed.

Eye Injuries↗
PubMed1976

Readaptation time after photo stress. Readaptation time as a function of oxygen concentration.

Optokinetic nystagmus (OKN) is used to study the eye's ReAdaptation Time (RAT) after a brief exposure to a light flash. The effects on RAT of breathing different concentrations of O2 are examined. Significant changes in RAT have been registered, showing that inhalation of 100% O2 as compared with room air, results in a shortened RAT (i.e. improvement), while inhalation of 9% O2 leads to an increased RAT (i.e. impairment). The physiology of RAT and the possible mechanisms behind the changes caused by different O2 concentrations are discussed. The findings of this group are compared with those of other studies.

Adaptation, Ocular↗
PubMed1975

Exophthalmometry.

Explore the source record for details and available documents.

Exophthalmos↗