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Biomedical subjects

C Hartmann

Publications and source records attributed to C Hartmann.

At least 37 records · Page 2Linked to original sources
PubMed1990

[Morphology of capsular sack retraction in relation to capsulotomy technique, lens design and sulcus-/saccus fixation].

Over a period of several months the dynamics and morphology of capsular retraction were analyzed with various capsulotomy techniques and IOL types implanted into the capsular bag or the sulcus. The techniques compared were peripheral and intermediate canopener capsulotomy, intermediate and small letter-box capsulotomy, intermediate and small capsulorrhexis with and without superior incisions. The posterior chamber IOLs implanted were one-piece and three-piece C-loop lenses and, in a limited pilot study, one-piece disk lenses. The authors' results indicate that capsular retraction and the stable position of the implant depend on the type, form, and size of the capsulotomy, the type of IOL and its fixation in the bag or sulcus. Any irregularity of the anterior capsule induces irregular capsular retraction with the risk of IOL decentration. Free-floating anterior capsular flaps may induce formation of iridocapsular synechiae. Contact between the anterior capsular rim and the posterior capsule results in capsulocapsular adhesions, capsular wrinkling, and capsular opacification of the contact zone. In order to avoid these capsulocapsular adhesions the diameter of the IOL optics should exceed that of the capsular opening in endocapsular implantation. However, peripheral capsulocapsular adhesions are necessary to stabilize IOL haptics, which for this reason must be of open design. Capsulocapsular adhesions may inhibit migration of lens epithelial cells in secondary capsular opacification. The ideal anterior capsulotomy technique seems to be the symmetrical, small, circular, continuous capsulorrhexis, if endocapsular implantation is desired. However, the technique is mainly designed for phacoemulsification, as a small capsulorrhexis inhibits nuclear expression in extracapsular cataract extraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrophy↗
PubMed1990

[Endothelial protection in surgical interventions and corneal donor tissue].

Perioperative iatrogenic lesions due to physico chemical trauma may worsen a primary endotheliopathy or lead to a secondary endotheliopathy with subsequent decompensation and corneal opacification. The incisions in anterior segment surgery induce permanent vertical cellular disparity, considering the peripheral endothelium in an area that may correspond to its germinative zone. Cells are lost by corneal folding, e.g., during nuclear expression or sutureinduced distortion. Floating nuclear particles and a high perfusion volume, e.g., during phacoemulsification or vitrectomy in aphakic eyes, create diffuse cellular necrosis. The same thing happens with chemically or osmotically inadequate perfusion media or extraocular solutions applied to the open eye during surgical interventions, e.g., to maintain mydriasis. Large areas of cell erosion are encountered after direct contact with instruments and PMMA. This has been one of the reasons for the development of new IOL materials like Poly-Hema or silicone that are less traumatizing for the endothelium. Long-lasting endothelial lesions result from direct contact with IOL haptics or mobile iris- or angle-supported lenses. The effect of a short post-operative rise in IOP on the endothelium is not clear. For all lens styles and materials, it still remains unclear whether there is chronic subclinical inflammation due to the IOL plastic material itself or not. To protect the endothelium, e.g., during cataract surgery, several techniques have been developed: preoperative hypotony; nuclear expression respecting corneal topography; the use of small amounts of mostly physiological rinsing solutions warmed to body temperature; endocapsular irrigation-aspiration; posterior chamber phacoemulsification; posterior chamber IOL implantation with an anterior chamber deepened by air and/or viscoelastics; postoperative reduction of the IOP.(ABSTRACT TRUNCATED AT 250 WORDS)

Cataract Extraction↗
PubMed1990

Changes in the electric resistance of the vaginal mucus in oestrous sows.

Changes in the electric resistance of the vaginal mucus were monitored in a large pig herd at 4-h intervals with a heat detector (Hauptner, Federal Republic of Germany) in multiparous sows (n = 16; litter size = 11.4 +/- 2.9) that showed a positive standing test and conceived. The initial value of resistance was 74.4 +/- 7.4 ohms. In 36 h this value gradually increased to 93.6 +/- 7.6 ohms. One to 2 h after the artificial inseminations (AI) lower resistance values were obtained, though the difference was not statistically significant. In the second part of the experiment 73.9% and 82.7% of the gilts (n = 92) and multiparous sows (n = 98) conceived, respectively, with an average litter size of 9.6 +/- 2.2 and 11.0 +/- 2.7, respectively. The conception rate of animals that immediately before AI had vaginal mucus resistance values between 75 and 90 ohms was about 20% higher. The only exception were 8 multiparous sows which had an average vaginal mucus resistance of 70 +/- 4.6 ohms after the first insemination. Litter size was also the biggest in sows with vaginal mucus resistance between 75 and 90 ohms. This difference was statistically significant for the multiparous sows. The heat detector is considered to be a useful complement to conventional methods of oestrus detection.

Animals↗
PubMed1989

Simultaneous determination of (R)- and (S)-celiprolol in human plasma and urine: high-performance liquid chromatographic assay on a chiral stationary phase with fluorimetric detection.

The quantitative enantiospecific determination of the beta 1-selective adrenergic antagonist (R,S)-celiprolol in human plasma and urine is described. It involves a two-step liquid-liquid extraction of celiprolol from biological material and separation of the underivatized enantiomers by high-performance liquid chromatography on a chiral stationary phase (cellulose tris-3,5-dimethylphenyl carbamate, coated on silica gel) with fluorimetric detection. R-(+)-Propranolol was used as an internal standard. The detection limits of 1.5 ng/ml enantiomer in plasma and 2.5 ng/ml enantiomer in urine at signal-to-noise ratios higher than 3 permit the performance of pharmacokinetic studies after therapeutic doses.

Adrenergic beta-Antagonists↗
PubMed1989

A new test for endothelial viability. The Janus green photometry technique.

A new in vitro technique was developed to measure, by simple photometry, the amount of Janus green extracted with absolute alcohol from isolated corneas after vital staining. The amount of stain corresponded to the percentage of damaged endothelial cells and was a reliable parameter of endothelial viability. More rapid and easier to perform than the usual cell counting of devitalized cells, this technique can be used to study the endothelial damage induced, for example, by experimental surgery, intraocular solutions, intraocular lens material, corneas storage solutions. As an example of application, results of the endothelial status after medium-term preservation of pig corneas (n = 40) in a modified McCarey-Kaufman medium at 4 degrees C were determined. The mean +/- endothelial damage was 8.5% +/- 1.8% (mean +/- SD) after 4 days, 29.5% +/- 3.7% after 7 days, 45.5% +/- 5.5% after 10 days, 69.3% +/- 3.7% after 14 days, and 100% after 20 days of storage in McCarey-Kaufman medium.

Animals↗
PubMed1989

[Endothelial precipitates and cytomegalovirus infection].

In patients with the typical features of intraocular cytomegalovirus infection endothelial precipitates were identified that had a characteristic morphology, which included subtle, non-pigmented linear deposits with reticular arrangement that can spread diffusely over the corneal endothelium without preference for the inferior quadrants. The appearance of these precipitates was comparable to heterocromic cyclitis. Specular microscopy identified lymphocytes and macrophages on the endothelial layer. The present observations are based on five case reports of necrotizing retinitis, typical for intraocular cytomegalovirus infection, in connection with the atypical endothelial precipitates. In four of the five patients reported, HIV-infection was confirmed. In one patient with serologically confirmed cytomegalovirus infection (however without HIV-infection), a diagnostic work-up of the aqueous humor was carried out. Local production of specific antibodies against cytomegalovirus was identified in the aqueous humor. Topical treatment with antiviral and/or steroidal drugs was unsuccessful. The antiviral drug gancyclovir was applied systemically in two patients, but there was no impact on the corneal precipitates described. No intravitreal therapy was given. If these endothelial changes can be regarded as pathognomonic for cytomegalovirus infection, thorough slit lamp examination may be important for diagnosis of the presence of or the reactivation of cytomegalovirus infection in the eye. So far, no correlation has been found between the time course of corneal/endothelial precipitation and necrotizing retinitis.

Acquired Immunodeficiency Syndrome↗
PubMed1989

[In vitro changes in the lens epithelium and corneal endothelium caused by the cytostatic drug daunomycin].

We evaluated the effects of the antiproliferative drug daunomycin on the viability and proliferation of cultured porcine lens epithelial cells. After a single short-term application, daunomycin penetrates the lens epithelial cells within 5 min. At a concentration of 2.5-7.5 mg/l, daunomycin has a low level of acute cytotoxicity and significantly suppresses the mitotic activity of the epithelial cells in culture. The daunomycin-induced endothelial lesions in freshly excised pig corneas were quantified with the Janus green photometry technique (n = 30) and studied with scanning electron microscopy (n = 9) in comparison to Ringer solution, which served as the control (n = 39). Whether the endothelial lesions were exposed to daunomycin or Ringer solution for 10 or 30 min seemed to make no significant difference. In addition, daunomycin did not seem to induce any morphological changes in the endothelial surface. These in vitro results confirm our clinical experience that daunomycin is apparently not harmful to the adult human corneal endothelium. Our results indicate that short-term endocapsular application of daunomycin during extracapsular cataract extraction, with or without IOL implantation, may prevent and/or delay the formation of capsular opacification.

Animals↗
PubMed1989

[In vitro corneal endothelial damage caused by intraocular lenses of PMMA, silicone and polyhema].

We compared the endothelial damage to freshly excised pig corneas (n = 156) as a result of contact with IOLs made of PMMA, silicone and polyhema. The contact time was 15 s, 1 min and 30 min. The endothelial damage was quantified with the Janus green vital staining photometric technique. Morphological changes were evaluated by scanning electron microscopy. The most damage was caused by PMMA (7.6%; 10.2%; 19.7%), followed by silicone (4.8%; 6.8%; 10.2%) and polyhema (4.6%; 5.9%; 8.3%). The degree of endothelial damage was statistically significant (P less than 0.01) in comparison with the control groups without any relationship to lens material or contact time. There was no significant difference between the damage caused by silicone and polyhema, but there was a significant difference between PMMA and silicone or polyhema.

Animals↗
PubMed1988

[One year after Chernobyl. Cesium-137 levels in premature, newborn and nursing infants and in younger and older children of Bonn and environs].

From May to August 1987, 137Cs activity was measured in a total-body counter (4 pi counter) in 33 premature and mature newborns (group I), 40 infants and young children up to 2 4/12 years of age (group II), and 15 children between 3 and 6 8/12 years (group III), all from Bonn or its environs. The mean of measurements in group II, at 3.7 Bq/kg body-weight, was lower than that of group I (5.8 Bq) and III (9.4 Bq). Mean radiation exposure, calculated from these data, was 1.7 mrem/a for group I, 1.1 mrem/a for group II, and 2.8 mrem/a for group III. A comparison with present Cs values in adults and measurements made at the end of the 1950's and beginning of 60's showed good agreement. There were no significant differences, as regards Cs activity, between newborns or infants who had been formula-fed or breast-fed. The measured radiation exposure of the three groups is about 1% of natural radiation exposure. Thus, present-day results indicate that there will be no damage to health outside the natural scatter.

Accidents↗
PubMed1988

Evaluation of daunomycin toxicity on lens epithelium in vitro.

Posterior capsule opacification is the major complication of extracapsular cataract extraction (ECCE). Lens epithelial cells derived from the periphery of the lens are thought to migrate posteriorly and contribute significantly to the postoperative proliferations at the posterior pole. We have evaluated the effects of the antiproliferative drug daunomycin on cultured porcine lens epithelial cell viability and proliferation. We observed that the mitotic activity of the cells is suppressed by a single short time treatment with daunomycin at a concentration as low as 2.5 mg/l. Long term effects on the reproductive capacity of the lens epithelial cells may not be as pronounced as the inhibition of other cells examined before e.g. retinal pigment epithelium and fibroblasts. Our results indicate that daunomycin may be useful for the pharmacologic prevention of postoperative proliferations in patients treated by ECCE.

Animals↗
PubMed1988

Endothelial alterations in AIDS with cytomegalovirus infection.

We report on a patient in whom a cytomegalovirus infection occurred in connection with AIDS. Together with the alterations of the fundus typical for cytomegalovirus retinitis, reticular deposits were observed on the corneal endothelium. Specular microscopy showed occasional endothelial cells with edema, as well as small, dark, round, mobile structures (probably lymphocytes) and large, bright, spindle-shaped, immobile structures (probably macrophages) located behind the endothelium. Despite treatment with corticosteroids and acyclovir, an increase in the extent of the findings was observed. The deposits are interpreted as a reaction of the endothelium to the cytomegalovirus infection.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Pyrroloquinoline quinone: a new redox cofactor in eukaryotic enzymes.

During the past decade pyrroloquinoline quinone has been shown to be a new redox cofactor for a range of bacterial alcohol dehydrogenases. Recent studies suggest that this cofactor may also be covalently bound to the active site of the eukaryotic copper amine oxidases. In this mini-review we present the evidence in support of pyrroloquinoline quinone as a novel eukaryotic cofactor. As a result of mechanistic advances during the last three years, together with a re-examination of previously existing data, a working model for the role of pyrroloquinoline quinone in enzyme-catalyzed amine oxidation reactions can be proposed.

Animals↗
PubMed1987

Reductive trapping of substrate to bovine plasma amine oxidase.

Plasma amine oxidases catalyze the oxidative deamination of amines to aldehydes, followed by a 2e- reduction of O2 to H2O2. Pyrroloquinoline quinone (PQQ), previously believed to be restricted to prokaryotes, has recently been proposed to be the cofactor undergoing reduction in the first half-reaction of bovine plasma amine oxidase (Ameyama, M., Hayashi, U., Matsushita, K., Shinagawa, E., and Adachi, O. (1984) Agric. Biol. Chem. 48, 561-565; Lobenstein-Verbeek, C. L., Jongejan, J. A., Frank, J., and Duine, J. A. (1984) FEBS Lett. 170, 305-309). This result is unexpected, since model studies with PQQ implicate Schiff's base formation between a reactive carbonyl and substrates, whereas experiments with bovine plasma amine oxidase have failed to provide evidence for a carbonyl cofactor. We have, therefore, re-examined putative adducts between substrate and enzyme-bound cofactor, employing a combination of [14C]benzylamine and [3H]NaCNBH3. The use of the relatively weak reductant, NaCNBH3, affords Schiff's base specificity and permits the study of enzyme below pH 7.0. As we show, enzyme can only be inactivated by NaCNBH3 in the presence of substrate, leading to the incorporation of 1 mol of [14C]benzylamine/mol of enzyme subunit at complete inactivation. By contrast, we are unable to detect any labeling with [3H]NaCNBH3, analogous to an earlier study with [3H]NaCNBH4 (Suva, R. H., and Abeles, R. H. (1978) Biochemistry 17, 3538-3545). We conclude, first, that our inability to obtain adducts containing both carbon 14 and tritium rules out the reductive trapping either of amine substrate with pyridoxal phosphate or of aldehyde product with a lysyl side chain and, second, that the observed pattern of labeling is fully consistent with the presence of PQQ at the active site of bovine plasma amine oxidase.

Amine Oxidase (Copper-Containing)↗
PubMed1987

Diffuse epithelial ingrowth after perforating keratoplasty.

Diffuse epithelial ingrowth was observed in 2 patients after perforating keratoplasty. Both cases involved a corneal graft after perforating injury with aphakia. In the first patient, the epithelial invasion was probably stimulated by a spatula synecholysis. In this case, the diagnosis was only made by histological investigation after enucleation. In the second patient the epithelial ingrowth was observed 8 months after keratoplasty. The clinical diagnosis was made on the basis of the typical slitlamp findings. In this case, the epithelial invasion led to hypotension with high resistance of outflow measured by electrotonography. In a very close chronological relation to the probable fall of chamber fluid secretion, development of a band-shaped keratopathy was observed.

Adult↗