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Biomedical subjects

G Høvding

Publications and source records attributed to G Høvding.

50 records · Page 3Linked to original sources
PubMed1983

Light-induced release of protoporphyrin, but not of zinc protoporphyrin, from erythrocytes in a patient with greatly elevated erythrocyte protoporphyrin.

A patient with greatly increased erythrocyte protoporphyrin, but normal porphyrins in urine and feces, is described. The patient later developed a malignant lymphoma, and the reason why she accumulated protoporphyrin in her erythrocytes is not known. The protoporphyrin in the erythrocytes consisted of two types of protoporphyrin, free protoporphyrin (30%) and zinc protoporphyrin (70%). Upon irradiation of erythrocytes in the absence of albumin, protoporphyrin and zinc protoporphyrin, which were both bound to hemoglobin, were released. In contrast, when the irradiation was carried out in the presence of albumin, the photohemolysis was negligible, and there was release of free protoporphyrin, but not of zinc protoporphyrin, from the erythrocytes. In vivo albumin is present in the plasma and the results may help to explain why patients with erythropoietic protoporphyria (erythrocytes containing free protoporphyrin) are photosensitive, whereas patients with lead intoxication and iron deficiency (erythrocytes containing zinc protoporphyrin) are not.

Aged↗
PubMed1982

Conjunctival and contact lens bacterial flora during continuous 'bandage' lens wear.

The conjunctival and contact lens bacterial flora in a group of 63 patients continuously wearing hydrophilic lenses for therapeutic reasons are reported. Thirty-three patients received topical antibiotics both before and during lens wear. There were no significant differences between the flora on the conjunctiva and on the posterior surface of the lenses. Coagulase negative staphylococci were the most commonly occurring microorganisms. Of these, Staph. epidermidis was the predominant species. Before lens fitting the conjunctival flora was significantly more scant in the group receiving topical antibiotics than in the other group (P less than 0.05). The same group showed an apparently increased bacterial growth after lens fitting, while an opposite trend was noted in the group not receiving topical antibiotics. However, none of these changes were even remotely statistically significant. The fitting of 'bandage' lenses does apparently not in itself necessitate the use of topical antibiotics.

Administration, Topical↗
PubMed1982

Variations in central corneal thickness during the first year of contact lens wear.

Variations in central corneal thickness during the first year of hard, hydrophilic or silicone lens wear are reported. The mean corneal swelling after 1/2,3 and 6 months was 4.7-3.0% in the first 2 groups (P less than 0.001 - P = 0.005), but only 1.3-0.8% in the latter group (P = 0.011 - 0.050). These differences were statistically significant (P less than 0.001 - P = 0.046) and are ascribed to a higher oxygen tension under the silicone lenses. An over-all reduction of corneal oedema was noted after 1/2 month (P = 0.025). One year after lens fitting a similar and not significant corneal swelling was found in the 3 lens groups. In addition to an initial 'osmotic' adaptation our results indicate that a further corneal adaptation to hard and hydrophilic lenses may take place between 6 and 12 months after lens fitting. Development of lens intolerance was not correlated to the degree of corneal oedema after 1/2 month of lens wear.

Adolescent↗
PubMed1982

Bacterial contamination of drops and dropper tips of in-use multidose eye drop bottles.

The type and frequency of bacterial contamination of 638 in-use multidose eye drop bottles are reported. By dripping, bacteria were recovered from 82 bottles (12.9%). Bacterial growth considered to be clinically and microbiologically significant were found in 12 cases (1.9%). The swabbings from 38 of 180 dropper tips (21.1%) yielded bacteria, while none of the pipette aspirates from 196 bottles were positive. The flora obtained by dripping and swabbing was very similar to the normal conjunctival and skin flora. It is suggested that microorganisms isolated by dripping often originate from contaminated dropper tips. The frequency of contaminated drops did not increase with increasing duration of use of the bottles. Repeated examinations and inoculation studies indicated that the solutions were self-sterilizing. This indicates that multidose eye drop bottles preserved and dispensed as in the present study may be used for more than the usual 4 weeks without increasing the risk of ocular infection.

Bacteria↗
PubMed1982

Porphyrin-induced photodamage as related to the subcellular localization of the porphyrins.

In liver cells photodamage following externally added protoporphyrin affects predominantly membrane associated components, whereas photodamage by uroporphyrin also affects water-soluble components. Following excess endogenous production of porphyrins, protoporphyrin concentrates in the mitochondria and exerts its photodamaging effect primarily on the mitochondrial system, whereas uroporphyrin concentrates in lysosomes with release and inactivation of lysosomal enzymes when irradiated. The results may be of importance to explain the different skin lesions in porphyria cutanea tarda and erythropoietic protoporphyria.

Animals↗
PubMed1982

Sideroblastic anemia with markedly increased free erythrocyte protoporphyrin without dermal photosensitivity.

A patient with idiopathic sideroblastic anemia and atypical clinical and biochemical findings is described. He had a greatly increased erythrocyte and plasma protoporphyrin, but normal urine and fecal porphyrins. The erythrocyte protoporphyrin had a fluorescence spectrum typical of free protoporphyrin, but caused no photosensitivity. Bone marrow metal chelatase activity was normal. There were no clinical signs of liver disease. The abnormal porphyrin metabolism in this patient is not known though a number of explanations are discussed.

Aged↗
PubMed1982

Erythropoietic protoporphyria terminating in liver failure.

A patient with erythropoietic protoporphyria was observed for 28 years. At the age of 38 years, cholestatic jaundice and rapidly deteriorating liver function developed. The patient died of massive bleeding from esophageal varices. During his terminal illness, the RBC protoporphyrin level rose to about 350 times the upper limit of normal, the urine contained increased protoporphyrins and coproporphyrins, but the stool porphyrin level was only moderately increased. Therapy with cholestyramine resin and vitamin E was associated with a decline in the RBC protoporphyrin level and a transient increase in the stool protoporphyrin level. The increase in RBC and serum protoporphyrin levels during the patient's terminal illness was not accompanied by an exacerbation of cutaneous photosensitivity.

Adolescent↗
PubMed1981

The conjunctival and contact lens bacterial flora during lens wear.

The conjunctival bacterial flora in wearers of hydrophilic, hard and silicone lenses and in a non-lens control group has been studied. Cultures were also taken from the posterior surface of the various contact lenses. Coagulase negative staphylococci were the most commonly occurring microorganisms both on the conjunctiva and on the lenses. Further identification of these bacteria showed Staph. epidermidis to be the predominant species. Compared with control group a significantly increased frequency of negative conjunctival cultures was found among the lens wearers (P = 0.020). The occurrence of coagulase negative staphylococci was reduced, but the difference was not statistically significant (P = 0.08). Gram-negative bacilli were more frequently found during lens wear (P = 0.012), but were mainly species which are traditionally regarded as apathogenic. The possible influence of lens disinfection, duration of lens wear and eye/lid hygiene on the conjunctival bacterial flora is discussed.

Actinomycetales↗
PubMed1981

Treatment of psoriasis of the scalp with betamethasone 17, 21-dipropionate plus salicylic acid lotion ('Diprosalic').

In an open study, 38 patients suffering from psoriasis of the scalp with various degrees of severity and duration, were treated for 4 weeks with a lotion containing 0.05% betamethasone 17, 21-dipropionate and 2% salicylic acid in a paraben-free vehicle containing isopropyl alcohol. The results showed agreement between the overall evaluation of response by patients and the physician using a 60 mm visual scale analogue. Marked relief of symptoms appeared after 1 week of treatment while clinical improvement appeared after 2 weeks. Slight degree of induration was present in 1 patient after 4 weeks of treatment, while 8 patients showed slight degree of scaling. After 2 weeks, excoriation disappeared in all the patients treated. Overall tolerance and cosmetic acceptability of the preparation were good.

Adolescent↗
PubMed1980

Effect of zinc on protoporphyrin induced photohaemolysis.

Zinc is readily inserted into protoporphyrin suspended either in a salt-sucrose buffered solution or endogenously present in red cell haemolysate in erythropoietic protoporphyria. Red cells from healthy persons were incubated with metal-free protoporphyrin or zinc-protoporphyrin and irradiated with light at 360-470 nm. The photohaemolysis was significantly less with zinc-protoporphyrin compared with that of the metal-free protoporphyrin. The results are discusssed in relation to the possibility of using zinc as a photoprotective and hepatoprotective agent in erythropoietic protoporphyria.

Animals↗
PubMed1978

Porphyrin production and liver involvement in a patient with erythropoietic protoporphyria.

The clinical and biochemical findings in a patient with erythropoietic protoporphyria are described. The patient had an extreme accumulation of protoporphyria in his erythrocytes and there was a thirty-fold increase in stool protoporphyrin. The patient also had elevated protoporphyrin in serum, bone marrow and liver. The porphyrins of the red blood cells, bone marrow and serum had fluorescence spectra different from that of the liver. Urine showed increased copra-, hepta- and uroporphyrins. Ferrochelatase activity in the bone marrow was less than 20% of that of non-porphyric controls. In spite of the extremely high levels of red cell protoporphyrin, the patient was clinically healthy with modest changes in liver function tests and liver histology. The results are discussed in relation to the development of liver damage and the recent findings of the effect of porphyrins on cell metabolism.

Adult↗