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Biomedical subjects

U Weber

Publications and source records attributed to U Weber.

At least 19 recordsLinked to original sources
PubMed1992

Carteolol incorporated into FAT-MLV liposomes: prolonged and decreased reduction of IOP.

Liposomes are used as carries providing a prolonged and improved drug action. They are capable of trapping beta-blockers such as Carteolol. In a randomized prospective double-blind clinical trial, Carteolol 2% suspended with frozen and thawed multivesicular large vesicles (FAT-MLV), FAT-MLV, and Carteolol 2% were applied to normal (slightly cataracterous) eyes and immediately after extracapsular cataract extraction or phakoemulsification with implantation of a posterior chamber lens in a standard procedure. Twenty-five patients were included in each group. Intraocular pressure (IOP) was measured for 3 days using applanation tonometry. In the normal eyes, a significant reduction of IOP was found for the patients receiving Carteolol and Carteolol MLV suspension. Moreover, an improved action and a prolongation of drug action was registered in the Carteolol/MLV group as compared to Carteolol treatment alone. After cataract operation, the control groups showed a significant increase in IOP. Carteolol produced a constant level of IOP but the Carteolol/MLV suspension showed a stronger decrease after ECCE and a still stronger decrease after phakoemulsification. Hence, Carteolol is suitable for the reduction of IOP but a Carteolol/MLV suspension is more effective, providing the possibility of a single application of a low-dose beta-blocker after cataract extraction with posterior chamber lens implantation.

Carteolol↗
PubMed1992

Effects of the prodrug loperamide oxide, loperamide, and placebo on jejunal motor activity.

This crossover, double-blind study investigated the effects of single oral doses of the prodrug loperamide oxide, which is reduced gradually to loperamide in the intestine, and loperamide on jejunal motor activity in 12 fasting healthy men. Five minutes after a phase III of the migrating motor complex (MMC), 2 mg loperamide oxide, 4 mg loperamide oxide, 4 mg loperamide, or placebo were administered. Thereafter, motor activity 10-30 cm abroad the ligament of Treitz was recorded with five catheter orifices at 3-cm intervals over 4 hr. Number of contractions and area under curve increased significantly with 4 mg loperamide and 4 mg loperamide oxide, the increases with loperamide oxide occurring more gradually. Placebo and 2 mg loperamide oxide had no discernible effects. With both 4 mg loperamide and 4 mg loperamide oxide, phase I of the MMC was slightly prolonged and phase II and the time from drug administration to the onset of the first phase III slightly shortened. The percentage of aborally propagated contractions in phase II increased with all active treatments, whereas the occurrence of phases III was not altered.

Administration, Oral↗
PubMed1992

The development of vernier acuity in human infants.

Vernier acuity, i.e. the detection of a small misalignment between lines, is about one order of magnitude finer than the resolution of periodic gratings in adult humans. This hyperacuity is generally attributed to cortical mechanisms, and the time-course of its development seems to differ from the development of grating resolution that probably is limited by retinal factors. We investigated 271 human infants and children between 2 months and 8 yr of age with essentially identical stimuli and experimental procedures. Vernier thresholds for Vernier targets were compared to grating resolution. The preferential looking experiments led to the following results: (i) Vernier acuity starts below grating resolution. (ii) Like grating resolution, Vernier acuity develops gradually, but more rapidly and longer; at the age of 5 yr performance becomes comparable to that of adults. (iii) Flanking borders without offset, added to the Vernier targets at various distances, did not affect thresholds consistently across distances and age groups.

Adult↗
PubMed1992

[Canthaxanthin retinopathy. Follow-up of over 6 years].

After long-term treatment with high dosages, canthaxanthin causes a characteristic retinopathy with circular, macula surrounding crystals. As changes in retinal functionning disappear relatively easily after withdrawal of the drug, the crystals dissolve rather slowly--over about several years. Five patients showing a profound crystalline retinopathy were re-examined with an average of 69.7 months after withdrawal of the canthaxanthin-containing drug. Three of the patients were treated for erythropoetic protoporphyria (EPP) with Phenoro (2/5 beta-carotene, 3/5 canthaxanthin), two sisters took a canthaxanthin-containing formulation (1/8 beta-carotene, 7/8 canthaxanthin) for cosmetic reasons. Two female patients complained about an increased glare sensitivity, which was explainable for one of them with a subcapsular cataract. The retinal crystals decreased quite differently. Minor deffects of the retinal pigment epithelium remained unchanged in two patients. They increased slightly in the female patient with the smallest crystal formation but highest plasma cholesterol. Shortly after withdrawal of the drugs usually an increase of a-wave amplituded of the electroretinograms was found. The a-waves returned to normal and the b-wave amplitudes showed an increase up to the final control paralleling the reduction of the retinal crystals. A- and b-wave peak latencies which were prolonged under treatment returned to normal.

Adult↗
PubMed1992

Effects of tetraethylammoniumchloride (TEA), vanadate, and alkali ions on the lateral leaflet movement rhythm of Desmodium motorium (Houtt.) Merr.

The period (approximately 3-5 min) of the ultradian rhythm of the lateral leaflet movement of Desmodium motorium is strongly lengthened (less than or equal to 30-40%) by the K+ channel blocker tetraethylammoniumchloride (20, 30, and 40 mM) and vanadate (0.5 and 1 mM), which is an effective inhibitor of the plasma membrane-bound H+ pump. The alkali ions K+, Na+, Rb+, and Cs+ (10-40 mM) shorten the period only slightly (less than or equal to 10-15%). Li+ (5-30 mM), however, increases the period of the leaflet rhythm drastically (less than or equal to 80%). We concluded that the plasmalemma-H(+)-ATPase-driven K+ transport through K+ channels is an essential component of the ultradian oscillator of Desmodium, as has been proposed for the circadian oscillator.

Activity Cycles↗
PubMed1992

[The effect of carteolol. Prolonged and increased effect by liposome suspension].

Liposomes are small lipid vesicles capable of trapping beta-blockers such as carteolol within their bilayer structure, the advantage being improved drug action, prolonged action time, and a reduction in drug concentration. In a prospective, randomized double-blind trial, carteolol 2%, liposomes (frozen and thawed multilamellar vesicles, FAT-MLVs), or carteolol 2% suspended with FAT-MLVs was applied to 25 eyes of 25 patients per group in a single 20 microliters dose. Intraocular pressure was measured for 3 days. A significant reduction in the IOP was observed in the patient groups receiving carteolol and carteolol suspended with liposomes. Moreover, improved action and prolongation of drug action was noted in the carteolol/MLV group as compared to carteolol treatment alone. Hence, carteolol 2% is suitable for reduction of IOP, but a reduction of drug concentration can be achieved by suspension with liposomes, thus reducing the side effects.

Animals↗
PubMed1991

The fat tumor suppressor gene in Drosophila encodes a novel member of the cadherin gene superfamily.

Recessive lethal mutations in the fat locus of Drosophila cause hyperplastic, tumor-like overgrowth of larval imaginal discs, defects in differentiation and morphogenesis, and death during the pupal stage. Clones of mutant cells induced by mitotic recombination demonstrate that the overgrowth phenotype is cell autonomous. Here we show that the fat locus encodes a novel member of the cadherin gene superfamily: an enormous transmembrane protein of over 5000 amino acids with a putative signal sequence, 34 tandem cadherin domains, four EGF-like repeats, a transmembrane domain, and a novel cytoplasmic domain. Two recessive lethal alleles contain alterations in the fat coding sequence, and the dominant fat allele, Gull, contains an insertion of a transposable element in the 33rd cadherin domain. Thus, this novel member of the cadherin gene superfamily functions as a tumor suppressor gene and is required for correct morphogenesis.

Alleles↗
PubMed1991

[Different effectiveness of two preparations of low molecular weight heparin in patients with elective hip joint replacement].

In an open randomised trial 3 regimen of prophylaxis for deep vein thrombosis were compared in 105 patients undergoing elective hip arthroplasty. One part of the patients received one injection daily of a low molecular weight heparin, another part was treated with one injection of a combination containing a different type of low molecular weight heparin + dihydroergotamine per day and a third part of the patients received 3 applications of 5000 IU unfractionated heparin per day. The frequency of DVT determined by the 125iodine-labelled fibrinogen uptake test and phlebography was 22.9% in patients receiving the combination and 50.0% in those receiving the low-molecular weight heparin alone. The difference was statistically significant with 2 p = 0.03. The incidence of DVT in patients receiving unfractionated heparin was 30.6%. No difference in the development of bleeding complications was found between the three treatment groups.

Adult↗
PubMed1991

High incidence of esophageal motor disorders in consecutive patients with globus sensation.

Thirty consecutive patients with globus sensation who were referred to a psychosomatic clinic prospectively underwent otolaryngological, videokinematographic, and manometric examinations of pharynx and esophagus to evaluate whether morphological abnormalities or motility disorders underlay their symptom. When indicated by findings, 24-hour pH-metry, scintigraphy of bolus transport, and esophagogastroscopy were performed. Seven patients were shown to have achalasia, 10 had "hypochalasia" (lower esophageal sphincter relaxation less than 75% with esophageal contraction abnormalities but no complete distal aperistalsis), and 1 had diffuse esophageal spasms; 2 patients had also hyperplastic lingual tonsils, 1 had tonsillitis, and 1 had a cervical spondylophyte. Nutcracker esophagus and nonspecific contraction abnormalities were found in 7 patients, and gastroesophageal reflux with esophagitis and a low lower esophageal sphincter resting pressure was found in 1; only 3 patients had normal esophageal motility. None had volunteered dysphagic symptoms at primary evaluation. Psychometric investigations in consenting patients showed no higher mean scores for state and trait anxiety, depression, hysteria, and hypochondriasis than in general medical outpatients. Esophageal motor disorders may, before giving rise to dysphagia, be sensed more vaguely and induce the globus sensation. However, only disappearance of the sensation after treatment allows inferring an etiological significance of such a disorder.

Adult↗
PubMed1990

The Drosophila seven-up gene, a member of the steroid receptor gene superfamily, controls photoreceptor cell fates.

The Drosophila seven-up (svp) gene was isolated as a lethal insertion in an "enhancer trap" screen. It is expressed and required in photoreceptor cell precursors R1, R3, R4, and R6 during eye development. The absence of svp+ function causes a transformation of these cells toward an R7 cell fate, as judged by morphology and expression of an R7-specific marker. This transformation depends in part on the sevenless gene product. Our results show that svp is involved in control of cell fate during the generation of neuronal diversity. Molecular analysis of svp reveals that it is a member of the steroid receptor gene superfamily and is likely to be a Drosophila homolog of the human transcription factor COUP.

Amino Acid Sequence↗
PubMed1990

[The vascularized pedicled flap of superior gluteal artery to hip bone chip--a new concept in the revascularization of hip necrosis in adults].

The development and introduction of microsurgical technique has made possible completely new concept of revascularisation surgery in femoral head necrosis. The bone graft described in this presentation is a pedicled one from the lateral ilium. In five femoral head necrosis a pedicled corticocancellous pelvic graft, supplied by the deep branch of the superior gluteal artery, was transplanted in the femoral head. In all cases it was possible to lift out the pelvic graft from the same side as the affected hip joint. Contrary to the medial iliac bone graft (deep circumflex iliac artery) the lateral iliac bone graft (deep branch of the superior gluteal artery) is inserted into the femoral head dorsally. Preoperatively and postoperatively performed selective angiographies are necessary and presented. In all cases an unimpeded perfusion could be shown three months postoperatively. Advantages and indications of the pedicled bone graft are discussed.

Adult↗
PubMed1990

Three-dimensional determination of an oblique osteotomy in the hip by mathematical optimization fulfilling some anatomical demands.

The present paper describes a nonlinear optimization process to estimate the single cutting plane of an oblique osteotomy in the hip. This kind of osteotomy was introduced and practised by Charit (Research report 81, University of Witwaters brand, Johannesburg, 1981). We calculate the cutting plane in such a way that the postoperative coverage of the resulting two parts of the femur are as great as possible whereby some anatomical constraint conditions are fulfilled. Additionally a simplified preoperative planning is described by using a sphere lying on the femoral head and determined by a least-squares method.

Biomechanical Phenomena↗
PubMed1990

Effect of ethylene glycol on rabbit retinas.

Electrophysiological and histological changes in rabbit retinas were induced by the oral application of ethylene glycol. The electroretinogram revealed a reduced photopic and scotopic activity. Birefringent crystalline deposits were found predominantly in the ganglion cell layer and the inner nuclear cell layer of the retina. These retinal findings were associated with depositions of calcium oxalate crystals in the rabbit kidney and liver.

Administration, Oral↗
PubMed1990

[Recombinant human erythropoietin (rh-EPO) in chronic, dialysis-dependent renal failure: effects on macro- and microcirculation and hematologic parameters].

Recombinant human erythropoietin (rh-EPO) has been shown to be effective in the treatment of renal anemia. Additionally, rh-EPO improves the hemostatic defect of uremia. On the other hand, a hypertensinogen effect and an increased risk for thrombosis have been reported in hemodialysis (HD) patients with rh-EPO. 20 HD patients in Homburg were recruited for a multicenter, placebo-controlled study (MF 3981), aiming to assess the risk of rh-EPO. Initially, 10 patients received rh-EPO at a dose of 3 x 80 U/kg body weight and week which was subsequently adjusted according to the hematocrit. After 6 months, the patients receiving placebo were changed to rh-EPO therapy. Clinical and laboratory data were obtained before, as well as 1, 3, 6 and 12 months after beginning of the study. Erythrocyte counts increased significantly in the rh-EPO group. Also, an increase of platelet count, fibrinogen and plasma viscosity was observed during rh-EPO. Tissue type plasminogen activator and plasminogen activator inhibitor as well as von-Willebrand-factor remained unchanged, although a shortening of the bleeding time was observed. Blood pressure and arterial blood flow were not influenced by rh-EPO.

Blood Viscosity↗
PubMed1989

Lesion and regeneration of the anterior and posterior lens capsule and cortex in rabbits Nd:YAG laser.

With a mode-locked Nd:YAG laser set at various energy levels, anterior and posterior capsular and cortical lesions were produced in the lens of rabbits. Biomicroscopic and Scheimpflug examinations showed the anterior lesion to be healing in a whitish scar that was restricted to the area of the original lesion. Histology and transmission electron microscopy (TEM) demonstrated the proliferation of epithelial cells that produced a new, continuous, basement membrane-like capsule. In the area of the lesion collagenous material, myofibroblast-like cells and macrophages were found. Laser-induced lesions in the posterior lens capsule and lens protein resulted in damage to the capsule and grey opacity of the lenticular proteins, which remained unchanged for 6 weeks. Neither inflammatory nor epithelial cells appeared within the locally damaged lens. Macrophages migrated from the vitreous into the lesion; they were observed either in intercellular clefts or within a lens fibre, almost completely taking up their cross section.

Animals↗