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Biomedical subjects

A Alm

Publications and source records attributed to A Alm.

At least 91 records · Page 5Linked to original sources
PubMed1981

Initial and long-term effects of metoprolol and timolol on the intraocular pressure. A comparison in healthy subjects.

The effect of 3% metoprolol and 0.5% timolol eye drops on the intraocular pressure (IOP) was compared in healthy subjects. The effect of a single dose was determined up to 48 h after administration of the drug before and after 2 weeks' treatment twice daily with the test drug. The study was performed as a randomized, double-masked cross-over study. Both drugs caused significant reductions in IOP with a maximal effect 2 to 8 h after administration of the drug. Timolol reduced the mean IOP from 14.8 to 10.7 mmHg after 2 h. The corresponding figures for metoprolol were 14.1 and 11.5 mmHg. There was no clear cut effect in the untreated eye for either drug. The effect of one drop timolol lasted for at least 48 h. The duration of one drop metoprolol was 36 h, but there was a marked reduction of the effect between 8 and 12 h after administration of the drug. Both drugs caused a smaller pressure reduction when the effect of one drop was followed for 48 h after to weeks' treatment compared to the initial response. This "escape" was of the same order for both drugs. It has been concluded that the composition of metoprolol eye drops used in the present study is less efficient than timolol as an ocular hypotensive agent.

Adult↗
PubMed1980

Effects of systemic and topical administration of metoprolol on intraocular pressure in healthy subjects.

The effect of a single dose metoprolol tablets or eye drops on intraocular pressure (IOP), blood pressure and heart rate was determined in healthy volunteers. The ocular tolerance of 6 weeks treatment with 1% eye drops was also studied. A 100 mg tablet reduced IOP for least 10 h with a maximum effect after 4 h corresponding to 32% of the pre-treatment pressure. The effects of 25 and 50 mg tablets were less pronounced and of a shorter duration. No consistent effect on blood-pressure was obtained, but doses that reduced IOP also reduced heart rate. A short-lasting reduction in IOP was obtained with 0.5% eye drops, while 1, 3 and 5% all caused significant reductions lasting at least 10-12 h. IOP was reduced by 13, 20 and 27% 4 h after administration of 1, 3 and 5% eye drops, respectively. No effect was observed in the contralateral, untreated eye, and no cardiovascular effects were obtained after administration of the eye drops. 1% eye drops administered twice daily for 6 weeks caused no clinically significant side effect.

Administration, Oral↗
PubMed1980

The effect of topical l-epinephrine on regional ocular blood flow in monkeys.

A 25 microliter volume of a 1-% l-epinephrine borate solution applied on the cornea of one eye in 12 monkeys reduced blood flow through the iris and the ciliary body by 59% and 20%, respectively, compared to the untreated control eyes. In the ciliary body the main effect was in the ciliary processes. Blood flow was determined with the labeled microsphere method 1, 4, and 6 hr after application of the drug. The average blood flow reductions were of the same order in the three groups, indicating a duration of at least 6 hr. No effect on blood flow through the retina or the choroid was observed.

Administration, Topical↗
PubMed1980

Permeability of the intraocular blood vessels.

This paper reviews quantitative studies on the permeability of the ocular blood vessels. In the retina, where there are tight junctions between the endothelial cells of the microvessels, there is very low permeability even to sodium ions. Glucose is transported through the capillary wall by a carrier, net glucose extraction amounting to about 12 per cent. In the choroid and ciliary processes, where there are fenestrated capillaries, the permeability to plasma proteins is about five times that in the kidney (another tissue with fenestrated capillaries), and ten to thirty times that in heart and skeletal muscle, which has non-fenestrated capillaries without tight junctions. Capillary permeability to low molecular weight substances is high in the choroid; sodium permeability is probably about thirty times that in heart muscle and fifty times that in skeletal muscle. This high permeability results in a high glucose concentration in the tissue fluid enabling rapid glucose movement into the retina.

Animals↗
PubMed1979

Studies on ocular blood flow and retinal capillary permeability to sodium in pigs.

A surgical technique was developed in pigs that permits access to the retinal venous plexus surrounding the optic nerve. The effect of surgery on ocular blood flow and capillary permeability was evaluated. Blood flow, determined by the labelled microsphere technique, did not differ significantly between operated and control eyes. Increased intraocular pressure in the operated eye reduced blood flow through the choroid and the anterior uvea in proportion to the reduction in perfusion pressure, while in the retina a smaller reduction in blood flow occurred indicating that autoregulatory mechanisms are involved in the control of retinal blood flow. The capillary permeability to sodium was studied by the single injection technique, using albumin as a reference substance. The fractional initial extractions from the choroidal and the retinal vessels were 0.77 and -0.001 respectively. The absence of a sodium extraction from the retinal vessel indicates that this part of the blood-retinal barrier was intact and that the blood drained by the retinal plexus is not mixed with blood from other sources.

Animals↗
PubMed1979

Retinal and choroidal contribution to retinal metabolism in vivo. A study in pigs.

The glucose metabolism of the retina was studied in vivo, by determining glucose, oxygen and lactate a-v differences for choroidal and retinal blood in pigs at different levels of intraocular pressure. At normal intraocular pressure the choroidal a-v differences were 0.07 and 0.11 mmol/l for glucose and oxygen respectively. The corresponding figures for the retina were 0.44 and 2.15. At increased levels of intraocular pressure the choroidal and retinal glucose and choroidal oxygen a-v differences increased, thus at least partly compensating for reduced blood flow. A major part of the oxygen and glucose consumed by the retina was delivered by the choroid. The total amount of oxygen extracted from choroidal and retinal blood could only account for complete oxidation of 37% of the extracted glucose. The results obtained in determinations of lactate a-v differences indicate that part of the remaining glucose is used for anaerobic glycolysis.

Animals↗
PubMed1979

The effect of metoprolol on intra-ocular pressure in glaucoma. A pilot study.

Eleven patients with previously untreated glaucoma of one eye were given metoprolol, 50 mg x 3 for one day. Intraocular pressure (IOP) and heart rate were significantly reduced during treatment, and increased after withdrawal of the drug. In the eyes with glaucoma, the mean IOP was reduced from 30.1 to 20.6 mmHg during treatment. Systolic and diastolic blood pressures were also reduced during treatment, but stayed at the same level after withdrawal of the drug. It is concluded that at least part of the reductions observed for IOP and heart rate are drug-induced, while the effect on blood preassure is mainly induced by factors other than the drug. The effect on IOP is considered large enough to be of clinical interest.

Aged↗
PubMed1979

Cavernous haemangioma of the retina.

Seven cases of retinal cavernous haemangioma are presented. Three cases have been followed for more than 6 years, and three cases between 1 and 2 years. Six cases had no eye symptoms related to the vascular tumour, while in one case vitreous haemorrhage occurred on two occasions. On both these occasions full vision was regained. None of the vascular tumours were treated. Two patients had grand mal seizures. They also had convulsive disease in the family history. In three cases family members of two generations were found to have normal eyes on examination.

Adult↗
PubMed1979

Healing of jejunal fistula using a silicone tube and patch.

In this case report is described a method of healing jejunal fistula by temporary use of a silicone tube and finally closing the defect in the intestinal wall by using a silicone patch. The patient was treated with parenteral nutrition during 7 months.

Humans↗
PubMed1978

Immediate effects of meniscectomy on the knee joint. The effects of tensile load on knee joint ligaments in dogs.

Tensile strength variables for the collateral ligaments were compared after excision of the meniscus in one knee, the corresponding meniscus in the contralateral knee of the same dog being intact. Removal of the meniscus was associated with a three-fold increase in initial laxity, two-fold for the lateral and three-fold for the medical ligament. The maximum tensile load uptake of the medial collateral ligament was reduced by more than 10 per cent after medial meniscectomy; the load uptake of the lateral ligament was not affected by lateral meniscectomy. It is proposed that tensile loads are distributed more favourably in the medial collateral ligament by the intact medial meniscus with firm capsular attachments than in the "normal" ligament after meniscectomy.

Animals↗
PubMed1977

Clinical experience with therapeutic arteriovenous fistulae.

Brescia-Cimino arterio-venous fistulae have been used as blood access for intermittent hemodialysis in 67 patients between 1972-74. The mean age of 32 men and 35 women was 48. Thirty-five patients were dialyzed through an external arterio-venous shunt for as long as 7 years before they received a fistula. Of 92 operations, 63 (68.5%) were successful. Ten patients (14.9%) never received a functioning fistula. The mean function time of 63 fistulae was 8.3 months. Twenty-two functioning fistulae eventually failed. In 11 cases no precipitating factor could be found. In six patients, septicemia coincided with infection at the fistula puncture site. Cardiac decompensation because of augmented venous return to the heart was not observed. Advantages and disadvantages with the Brescia-Cimino fistula are discussed and compared with the Quinton-Scribner shunt.

Adolescent↗