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Biomedical subjects

E Demant

Publications and source records attributed to E Demant.

9 recordsLinked to original sources
PubMed1986

High prevalence of anti-mitochondrial antibodies among patients with some well-defined connective tissue diseases.

A sensitive enzyme linked immunosorbent assay for determination of low levels of anti-mitochondrial antibodies (AMA) has been developed. With this method, sera from patients with primary biliary cirrhosis (PBC) and patients with different connective tissue diseases were investigated. Ninety percent of PBC sera were found to harbour high levels of AMA and a high proportion of patients with systemic lupus erythematosus (SLE), but also other patients with connective tissue diseases were found to have low affinity or low concentrations of AMA in their sera. AMA positive sera were further investigated with sodium dodecyl sulphate polyacrylamide gel electrophoresis and immunoblotting technique. PBC showed reactivity to 70, 50 and 45 kD mitochondrial polypeptides. SLE sera showed reactivity to 70 and 45 kD polypeptides and furthermore to a 65 kD polypeptide. Many of the AMA positive sera from patients with connective tissue diseases reacted to a 65 kD polypeptide.

Arthritis, Rheumatoid↗
PubMed1983

Cone and rod ERGs in degenerations of central retina.

Sixty-four patients with retinal degenerations at the posterior pole were reviewed and their ERGs analysed. On the basis of symptoms, visual acuity, ophthalmoscopy and cone/rod ERG the patients were divided into five diagnostic groups: Stargardt's disease, fundus flavimaculatus, cone degeneration, dominant drusen and central retinitis pigmentosa (RP). Stargardt's disease and fundus flavimaculatus show low-normal or subnormal cone b-wave amplitudes, often with prolonged peak times; the rod ERG is rarely abnormal. Cone degeneration presents with reduced visual acuity, photophobia, nystagmus and minimal fundus changes. The ERG shows severely reduced cone b-waves and increased peak times; the rod b-waves are in the low-normal or subnormal range. Dominantly inherited drusen, included for comparison, revealed little change in the ERG in spite of widespread ophthalmoscopic changes: b-wave amplitudes fall mostly in the low-normal range, and their peak times may be prolonged. RP of the central type reveals considerable variability in all clinical aspects, but the cone and rod ERGs are consistently greatly reduced, showing markedly increased peak times of the cone b-waves. Recording of the Ganzfeld ERG with cone/rod separation thus proves useful in differentiating degenerations of the central retina.

Adolescent↗
PubMed1982

Changes in pO2 induce retinal autoregulation in vitro.

Vascular autoregulation maintains stable retinal function in vivo in the face of changes in arterial pO2. We observed autoregulatory changes in the flow of perfusate through the isolated cat eye in response to changes in pO2. Hydrostatic perfusion pressure and all other variables of the perfusate, except for pO2, were kept constant. Throughout the experiments the viability of the eye was monitored by electroretinography. In nine short periods of hypoxia, pO2 of the perfusate was reduced by 12%-42% compared to the control. In eight of these experiments the flow rate of the perfusate increased significantly. Retinal vasodilation during hypoxia was also documented by indocyanine green angiography, monitored by TV, and photographed. In seven periods of hyperoxia, pO2 was raised by 7%-38%. In all cases the flow of the perfusate decreased. These changes in flow are interpreted as resulting from autoregulative vasodilation and vasoconstriction of the retinal vessels. The b-wave of the ERG increased and decreased parallel with pO2 of the perfusate. This indicates that autoregulation in vitro does not sufficiently compensate for changes in pO2. This is in contrast to our findings from a previous study in the anesthetized cat.

Animals↗
PubMed1982

Effects of changes in arterial Po2 and Pco2 on the electroretinogram in the cat.

Changes in components of the electroretinogram during hyperoxia, hypoxia, and hypercapnia were studied to demonstrate retinal vascular autoregulation by electrophysiologic means. Autoregulation of the retinal arterial network is shown to stabilized the b-wave during hyperoxia (arterial PO2 of 395 mm Hg). During marked hypoxia, under ventilation with 10% and 5% O2, the b-wave decreased, indicating failure of autoregulation at the corresponding arterial PO2 levels of 30 and 26 mm Hg. During hypercapnia, possible autoregulatory effects were counteracted by a low arterial pH, which decreased the b-wave amplitude. The findings provide new electrophysiologic evidence for autoregulation of the retinal vessels. The c-wave during changes in arterial PO2 and PCO2 underwent changes that correlate inversely with fluctuations in blood pressure that occurred during ventilation with test gas mixtures. Considering the linear relationship between blood pressure and choroidal flow, we suggest that the latter influences the amplitude of the c-wave.

Animals↗
PubMed1982

Effects of changes in systemic blood pressure on the electroretinogram of the cat: evidence for retinal autoregulation.

Systemic blood pressure was increased and decreased in anesthetized cats by intravenous infusion of angiotensin and by gradual exsanguination, respectively. The b- and c-wave amplitudes of the electroretinogram were used as indicators of activity of the inner retina and outer retina with pigment epithelium, which are supplied by the retinal and choroidal circulations, respectively. The amplitude of the b-wave remained stable during increases in mean arterial blood pressure (MABP) up to 225 mm Hg but decreased rapidly if the MABP was lowered below 55 mm Hg. This wide range of stability of the b-wave is likely to be brought about by autoregulation of the blood supply to the inner retina. No such stability was seen in the c-wave, the amplitude of which changed inversely to increases or decreases in the MABP. The c-wave thus appears to respond to changes in choroidal blood flow. The data provide new electrophysiologic evidence for autoregulation of the retinal vasculature and suggest that choroidal blood flow may influence the amplitude of the c-wave.

Animals↗
PubMed1980

Canaliculitis: review of 12 cases.

Canaliculitis must be considered in patients with chronic unilateral conjunctivitis. Pouting of the punctum, canalicular swelling and expression of particulate matter or stones are important clinical signs, and dacryocystography often helps in diagnosis. Meticulous microbiologic studies may not reveal actinomycetes. Canaliculotomy with silver nitrate cauterization is effective treatment.

Aged↗
PubMed1977

An experimental model of candida endophthalmitis.

With the more widespread use of hyperalimentation, systemic steroids and broad spectrum antibiotics, particularly in immunologically suppressed patients, Candida endophthalmitis is becoming more common. The drugs that are used to treat it are very toxic; treatment should be stopped as soon as possible. We wished to know if the clinical appearance of a lesion could be related to the number of organisms in it. We injected 16 rabbits intravenously with a suspension of Candida Albicans and produced typical ocular lesions in all of them. The fundi were observed by indirect ophthamoscopy and periodically groups of rabbits were killed and quantitative cultures of their eyes were made. Our results show that this experimental model gives reproducible results. We found that when the lesions are beginning to regress, culture shows either no or very little growth. If, in the human, the ophthalmoscopic appearance of a lesion is similarly related, it could be a guide in deciding the need to continue treatment.

Animals↗