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Biomedical subjects

G Hopen

Publications and source records attributed to G Hopen.

34 records · Page 2Linked to original sources
PubMed1982

Intraocular lenses and experimental bacterial endophthalmitis.

To determine if an intraocular lens renders bacterial endophthalmitis more resistant to therapy, an animal model was developed. Nine rabbits underwent bilateral extracapsular lens extraction with placement of a Simcoe posterior chamber IOL in one eye. Approximately 170 organisms of Staphylococcus aureus were inoculated into both eyes. The eyes of seen animals were treated with intravitreal and subconjunctival gentamicin after 24 and 48 hours. Vitreous cultures remained sterile in all treated eyes for one week after antibiotic therapy. Two animals that did not receive antibiotics showed persistent infection. There was no difference between aphakic and pseudophakic eyes in terms of clinical response or onset of negative cultures.

Animals↗
PubMed1981

Corneal toxicity with systemic cytarabine.

Three patients with leukemia developed corneal toxicity while receiving high doses (3 g/m2) of systemic cytarabine. Symptoms began five to seven days after initiation of treatment with high doses of systemic cytarabine and consisted of ocular pain, tearing, foreign-body sensation, photophobia, and blurred vision. All three patients developed bilateral conjunctival hyperemia and fine corneal epithelial opacities and refractile microcysts that were more numerous in the central than in the peripheral cornea. The symptoms disappeared without treatment in approximately one week. The corneal changes we observed with high doses of systemic cytarabine resembled descriptions of corneal toxicity from topical cytarabine and were probably secondary to inhibition of DNA synthesis in the corneal epithelium.

Corneal Diseases↗
PubMed1981

Granulocyte and platelet adhesiveness in malignant paraproteinaemia, leukaemia and myeloproliferative diseases.

Granulocyte and platelet adhesiveness were measured in 36 patients with haematologic diseases, using a glass bead column assay. Platelet adhesiveness (PA) was reduced in malignant paraproteinaemia (l3/20), leukaemia (10/11) and myeloproliferative diseases (3/5). Granulocyte adhesiveness (GA) was reduced in most patients with paraproteinaemia and leukaemia, but results of measurements in whole blood and in suspensions of leucocytes in autologous plasma were poorly correlated due to the influence of abnormal platelet function and/or concentration on the measurement of GA in whole blood. The results of experiments combining leucocytes and plasma from patients and controls indicate that impaired GA in paraproteinaemia is due to a plasma factor, whereas a cellular defect is responsible for the reduced GA in leukaemia.

Granulocytes↗
PubMed1981

Vitreous fluorophotometry: identification of sources of variability.

Slit-lamp vitreous fluorophotometry (VF) has been used by several investigators to document the early breakdown of the blood-ocular barrier. After an injection of fluorescein, levels of fluorescein in the vitreous humor are reported to be elevated in diabetic patients compared with controls even when there is no retinal pathologic condition discernible by angiography or ophthalmoscopy. We have examined the technique of VF in normal persons and have identified several potential sources of error in the determination of vitreous fluorescein levels. Fluorescein in the choroidal circulation significantly influences VF readings taken at the retinal surface and in the posterior vitreous. This effect is modulated by ocular pigmentation, with heavy pigmentation of dark-eyed normals more effectively screening out choroidal fluorescence than the light pigmentation of blue-eyed subjects. Influence of choroidal fluorescein extends toward the midvitreous, and the range of influence is directly related to the slit width of the exciting light. At narrow slit widths the effect is diminished but can never be completely eliminated. Blood fluorescein levels decrease with time, and since choroidal fluorescein contributes to VF values, the time after injection that VF reading are taken is a critical parameter.

Adult↗
PubMed1981

Porphyrin-induced photodamage to isolated human neutrophils.

Human neutrophils were irradiated with light at 340-380 nm in the presence of low concentrations of protoporphyrin or uroporphyrin. At increasing light doses or increasing concentrations of protoporphyrin, the neutrophils rapidly lost the ability of locomotion. Also, neutrophil chemiluminescence and hexose-monophosphate shunt activity rapidly declined. An early event was leakage of endogenous K(+) followed by lactate dehydrogenase and at a later stage leakage of particle-bound acid phosphatase. A number of cellular enzymes were inactivated, the susceptibility to inactivation decreased in the order: succinate dehydrogenase greater than lactate dehydrogenase greater than glutamate dehydrogenase greater than acid phosphatase. Uroporphyrin had no effect on neutrophil functions, leakage of K(+), or cellular enzymes. The results suggest that photodamage to the plasma membrane and the mitochondria are earlier events than photodamage to lysosomes.

Humans↗
PubMed1981

Fatal carbamazepine-associated hepatitis. Report of two cases.

Fatal hepatitis associated with intake of carbamazepine occurred in two females, 37 and 23 years old. The former used carbamazepine to prevent alcohol withdrawal symptoms. She had also been treated with disulfiram. The latter had used the drug as the only medication for epilepsy. This report supports the view that carbamazepine may induce serious hepatic damage.

Adult↗
PubMed1980

Influence of plasma factors and drugs on in vitro leukocyte adhesiveness.

Leukocyte adhesiveness was studied by measuring the retention of leukocytes in glass bead columns after the passage of heparinized whole blood or leukocyte suspensions. Leukocytes adhered readily to glass beads and independently of divalent cations when proteins were absent. Addition of plasma inhibited leukocyte adherence which became increasingly dependent on divalent cations. In conflict with results reported from nylon wool column experiments, we could not demonstrate a leukocyte adherence augmenting effect of zymosan activated plasma or plasma from patients with inflammatory diseases or patients undergoing hemodialysis. Ethanol and lidocaine gave a dose response inhibition of leukocyte adherence. The conflicting results obtained with the nylon wool and the glass head column techniques in conditions with "augmented adherence" may be due to retention of leukocyte aggregates in the nylon wool columns.

Blood Proteins↗
PubMed1979

Retention in glass bead columns as a measure of leucocyte adhesiveness. I. Influence of sample size and erythrocyte sedimentation.

Erythrocyte sedimentation significantly influenced test results when leucocyte retention in glass bead columns was used as a measure of leucocyte adhesiveness. In blood with elevated ESR, this influence was especially evident. Erythrocyte sedimentation highly increased leucocyte retention in vertical columns with a downward flow, whereas in slightly tilted columns with an upward flow, the retention was reduced. The error in measurements caused by erythrocyte sedimentation could be corrected by means of the haematocrit values in samples and eluates. Correction was better for results obtained with slightly elevated than with vertical columns. The granulocyte retention rates increased with increasing sample size, whereas lymphocyte retention remained constant.

Blood Sedimentation↗
PubMed1979

Retention in glass bead columns as a measure of leucocyte adhesiveness. II. Influence of platelets and erythrocytes.

The influence of platelets and erythrocytes on the retention of leucocytes in glass bead columns was studied. Leucocyte retention increased when platelet retention was stimulated by the presence of erythrocytes. In the presence of only a few erythrocytes, platelet retention was low, and platelets did not influence leucocyte retention. When only a small number of platelets was present, erythrocytes inhibited leucocyte retention. The platelet-dependent leucocyte retention increased as the volume passed through the columns was increased. However, the platelet-independent leucocyte retention did not change when the sample size was increased. In blood from patient with thrombocytopenia or defect in platelet function and in normal blood treated with inhibitor of platelet adhesion, neutrophil retention was reduced. However, erythrocyte-free leucocyte suspensions from these cases showed normal leucocyte retention. Thus, experiments with whole blood may serve as a model for the study of platelet-leucocyte interaction. However, for the study of leucocyte adhesiveness per se, isolated leucocytes seem more suitable than whole blood.

Adult↗
PubMed1979

Adhesion and locomotion of human leukocytes in vitro; importance of protein coating; effect of lidocain, ethanol and endotoxin.

The adhesion of leukocytes to glass beads in protein-free media was quantitatively high and not dependent on divalent cations. Addition of plasma, albumin or gelatin in increasing concentrations gradually reduced leukocyte adhesion, which then became increasingly dependent on divalent cations. Heat inactivation of plasma did not affect leukocyte adhesion. Leukocyte migration in glass capillary tubes, which was dependent on a heat labile plasma factor, was promoted by each of the proteins listed and by siliconizing the tubes. Leukocyte migration in millipore filters was enhanced when albumin was present in the cell starting compartment. Lidocain reduced both leukocyte adhesion to protein-coated glass and leukocyte migration in capillary tubes and millipores filters. Ethanol reduced leukocyte adhesion and leukocyte filter migration. E. coli endotoxin enhanced adhesion of leukocytes but inhibited their migration in tubes and filters. The findings indicate the existence of a relationship between adhesion and migration of leukocytes.

Cations, Divalent↗
PubMed1975

Cerebrotendinous xanthomatosis (cholestanolosis). Investigations on two sisters and their family.

Two sisters, aged 38 and 32, suffering from cerebrotendinous xanthomatosis are described. The most important clinical findings were xanthomas, central nervous affection with motor and mental dysfunction, EEG changes and juvenile cataract. The diagnosis was established by the demonstration of increased amounts of cholestanol in serum. Both sisters had amenorrhea, and their excretion of dehydroepiandrosterone in the urine was increased. In the elder sister, the levels of urinary 17-keto steroids, androsterone and estradiol were also increased. Other unusual features of the disease in the elder sister were hyper-prebeta-lipoproteinemia and serum cholesterol in the higher normal range.

Adult↗