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Biomedical subjects

M Wenzel

Publications and source records attributed to M Wenzel.

At least 73 records · Page 4Linked to original sources
PubMed1991

AGN 190383, a novel phospholipase inhibitor with topical anti-inflammatory activity.

AGN 190383 is a 5-hydroxy-2(5H)-furanone ring analog of the marine natural product manoalide. When applied topically, AGN 190383 inhibits phorbol ester induced mouse ear edema. It is a potent inhibitor of bee venom phospholipase A2 and blocks the release of arachidonic acid from calcium ionophore A23187 stimulated human neutrophils. AGN 190383 also inhibits both hormone-operated and depolarization-dependent calcium mobilization in GH3 cells, as well as fMLP stimulated increases in free cytosolic calcium in human PMNs. Furthermore, it is also able to block the release of the neutral protease elastase from stimulated neutrophils. The effects of AGN 190383 on arachidonic acid metabolism and leukocyte function may account, in part, for its anti-inflammatory activity in vivo.

Administration, Topical↗
PubMed1991

Aortocoronary vascular prosthesis made of siliconized homologous vein or bovine sacral artery.

The purpose of our study was to develop and prepare aortocoronary prostheses, test them experimentally in multivascular and coronary reoperations in case of missing autologous grafts and to use them for shunt operations in cardiac surgery. Human vein or bovine sacral artery were used for preparing aortocoronary prostheses. As for metrics of 9-14 Charr. and a length of 20-30 cm were obtained. Aortocoronary prostheses were preformed according to the coronary configuration for left descending artery, circumflex artery and right coronary artery. Aortocoronary prostheses meet the conditions of desantigenicity, sterility, athrombogenicity, tightness and high tensile strength, tear propagation strength, bursting pressure and shrinkage temperature. Experimental testing was performed in dogs in aortofemoral and aortocoronary positions. Infections did not occur. The healing process and structural changes of aortocoronary vascular prostheses (grafts) were examined histologically and evaluated by means of scanning electron microscopic examinations. Athrombogenicity and healing-in without inflammation and calcification were proved.

Animals↗
PubMed1991

[Prevention of cellular foreign body reactions to lens implants].

A heparin-surface-modified PMMA IOL has recently been developed in order to give the IOL a hydrophilic surface and to reduce postoperative inflammatory reactions in the eye. It is known that severe inflammation accompanies a tremendous increase in leucocytes in IOLs. A foreign-body reaction is characterized by the formation of histiocytic giant cells. The topical administration of corticosteroids, or the surface passivation of IOLs, cannot prevent a foreign-body reaction. Specular microscopy was used for in vivo investigation of cellular reaction in IOL surface of heparin-surface-modified lenses versus regular PMMA lenses. The double-masked and randomized study included 53 patients investigated 1 week and 1 month postoperatively. Small, round, and spindle-shaped cells were the cells most frequently observed after 1 week. These cells were identified in all cases. They were found in a higher density on the surface of the control lenses (43 cells/mm2) than on the heparin-surface-modified lenses (25 cells/mm2). Giant cells were found in two patients after 1 week; both of these patients belonged to the control group. Small, round, and spindle-shaped cells were also seen in all patients 1 month postoperatively. Again, they were found in a higher frequency on the control lenses (38 cells/mm2) than on the heparin-surface-modified lenses (13 cells/mm2). Giant cells were found in 18 patients 1 month postoperatively. They were found exclusively on the control lenses; the difference was significant (p less than 0.0001).

Follow-Up Studies↗
PubMed1991

An alternative to 'two-step' tuberculin skin testing for Southeast Asian refugees.

Previous studies report that Southeast Asian refugees demonstrate very high incidences of positive reactions to two-step tuberculin testing. In spite of these findings, fiscal restraints have limited the use of two-step testing in some of the centers that screen large numbers of these refugees. In this study, 101 Southeast Asian refugees were studied for their antigenic response to the tuberculin skin test. Forty-nine had positive reactions when the tuberculin skin test was read at 48 hours. Of the 52 refugees who showed a negative reaction at 48 hours, 22 had positive reactions when read a second time, three to five days later. The 28 refugees with negative reactions at both 48 hours and at five to seven days underwent two-step tuberculin testing. Only two of the 28 demonstrated positive reactions with two-step testing. Of the refugees with positive reactions at 48 hours, all but one continued to show positive reactions when the skin test was read a second time, at five to seven days. These findings suggest that a single tuberculin skin test, read at five to seven days, may provide a cost-effective alternative to two-step tuberculin testing for Southeast Asian refugees.

Adolescent↗
PubMed1990

Cellular reactions on heparin surface-modified versus regular PMMA lenses during the first postoperative month. A double-masked and randomized study using specular microphotography.

Specular microscopy was used for investigation of cellular reactions on the intraocular lens (IOL) anterior surface of Heparin surface-modified (HSM) versus regular polymethylmethacrylate (PMMA) lenses (Pharmacia types 700C versus 700B, respectively). The double-masked randomized study included 53 patients investigated at 1 and 4 weeks postoperatively. Giant cells were only found on control lenses and more frequently at 4 weeks. Small cells were found on both lens types, but in a higher frequency on the control lenses. The number of small cells decreased during the first 4 weeks on both the control and HSM lenses. However, those control lenses that had giant cells on their surface showed an increase in the number of small cells during the same time. The results of the current study show that HSM lenses give rise to less postoperative inflammatory cellular reactions than regular PMMA lenses.

Aged↗
PubMed1990

[Iritis following cataract operations. Historical retrospective with critical comments on a so-called "toxic lens" syndrome].

Postoperative inflammation is one of the oldest complications of cataract surgery. It was described by the Indian Susruta as early as 500 BC. Following the introduction of cataract extraction by Daviel in 1745, these operations attracted increasing interest. In 1786 de Wenzel distinguished two types of postoperative inflammation. In the dangerous type there was involvement of the entire eye and severe pain; in the benign type, which began in the first few postoperative days, the conjunctiva and lids were not involved, and even if hypopyon developed there was no severe pain. During the 19th century, the possible causes of the benign type of iritis were discussed, including infection, phacoanaphylaxis, trauma, toxicity of irrigation solutions etc. In the early days of implantation of intraocular lenses, from 1949 onward, postoperative inflammation was common. However, it was not until 1980 that the term "toxic lens syndrome" was introduced. The clinical descriptions do not differ much from other descriptions of benign iritis published during the last 200 years. Therefore, it does not seem that there is any great advantage to be gained by using this new term.

Cataract Extraction↗
PubMed1990

Increased concentrations of a circulating sodium pump inhibitor in essential hypertension and uraemia and its partial purification from haemofiltrate.

Patients with essential hypertension have 3.2 fold and patients with chronic uraemia 11.7 fold higher serum concentrations of endogenous digitalis-like activity than normotensives (76.3 +/- 9.3 nM). Upon haemodialysis this serum activity drops to almost normal values. A low molecular factor could be partially purified from 4000 l haemofiltrate.

Aged↗
PubMed1990

[Immunohistochemical studies of the human lens capsule].

In this study we made an attempt to localize components of the human lens capsule using immunohistochemical methods. Type IV collagen could be shown in all parts of the capsule in equal distribution. It could be found over the whole thickness of the lens capsule. By comparison, laminin could be detected only at the inner layer of the capsule. There was no difference concerning the contribution of these components between the anterior and the posterior capsule. No specific staining of collagen types I and III or of fibronectin could be found.

Collagen↗
PubMed1989

[Enoxacin concentrations in serum and in the wall of the colon during colorectal surgery].

For successful prophylaxis of postoperative infections in colorectal surgery the administered antibiotic must reach sufficiently high concentrations in plasma and gut wall. Therefore, in ten patients receiving 400 mg enoxacin orally about 2 h prior to operation (in addition to their routine perioperative intravenous prophylaxis with amoxicillin and clavulanic acid) concentrations of enoxacin were determined by HPLC in plasma (samples were taken at the beginning of operation, time of tissue sampling and each hour during the operation) and in gut wall. We found the following plasma concentrations (mean +/- S.D.): beginning of operation 2.53 ( +/- 1.07) mg/l, 1 h later 2.08 ( +/- 0.82) mg/l, 2 h later 1.60 ( +/- 0.65) mg/l. At the time of tissue sampling (on an average 185 min after the enoxacin dose) the plasma concentration was 2.27 ( +/- 1.02) mg/l, the gut wall concentration was 3.74 ( +/- 1.58) mg/kg, the ratio between the two concentrations was 1.70 ( +/- 0.27). It seems warranted to study orally administered enoxacin (in combination with an antibiotic against anaerobes) in prophylaxis of infections after colorectal surgery.

Aged↗
PubMed1989

[Cell density of the corneal endothelium following cataract surgery].

Endothelial cell loss following extracapsular cataract extraction and implantation of a posterior chamber lens was studied and the influence of various factors analyzed. In 56 eyes, the mean reduction in cell density in the superior zone of the cornea was 19%. In the eyes with epithelial edema endothelial damage was more severe than average. Lower cell density was also found in particular in patients over 75 years old and those with pre-existing cornea guttata. In contrast, preexisting glaucoma, a history of corneal trauma, and, astonishingly, the surgeon's experience had no detectable influence on endothelial cell damage.

Aged↗
PubMed1989

[Corneal endothelial damage in congenital and juvenile glaucoma].

Corneal changes are typical for infantile glaucoma. In newborns, Descemet's membrane and the stroma are still soft, and distend when intraocular pressure rises. Cell counts were performed under the reflecting microscope to determine whether the endothelium is affected when corneal diameter increases and changes occur in Descemet's membrane. The mean endothelial cell density of 20 patients with congenital or secondary juvenile glaucoma, aged between 4 and 29 years, was found to be 2780/mm2. Even though increased corneal diameter was the most common primary symptom of buphthalmos, there were no relationships between corneal diameter on the one hand and postoperative endothelial cell density, visual outcome, or postoperative pressure on the other. In children who had had corneal edema followed by ruptures of Descemet's membrane the number of endothelial cells was significantly reduced, visual outcome was worse, and there were more problems with regulation of intraocular pressure. Lower-than-average endothelial cell densities were also found in some patients with secondary glaucoma.

Adolescent↗
PubMed1989

Pituitary hyposecretion and hypersecretion produced by a Rathke's cleft cyst presenting as a noncystic hypothalamic mass.

A 53-year-old man presented with polydipsia, polyuria, lightheadedness on standing, and syncope. Visual field deficits suggesting left optic tract compression and pituitary dysfunction consisting of diabetes insipidus, hyperprolactinemia, and anterior pituitary insufficiency were diagnosed. On the computed tomography scan, an isodense, ring-enhancing, parasellar mass was localized primarily in the suprasellar region and also extended into the sella. It was believed that the pituitary hormone hypersecretion and hyposecretion were due to hypothalamic dysfunction from the mass which was initially believed to be a craniopharyngioma. At surgery a Rathke's cleft cyst was resected. The unusual presentation of this Rathke's cleft cyst presenting as a hypothalamic lesion is discussed.

Craniopharyngioma↗
PubMed1989

[Effects of different buffers, ethanol and hydrogen peroxide on the morphology of cultured brain cells].

Effects of different buffers: N-2-Hydroxyethylpiperazine-N-2-ethanesulfonic acid (HEPES), Ethanolamine (2-Aminoethanol), sodium bicarbonate (NaHCO3) in the presence of 0.003% H2O2 or 0.5% ethanol were investigated on cell cultures from brain (chick embryo 5 1/2 or 9 day in ovo). Morphological parameters: density of cells, reaggregation, size of cell aggregates were used. H2O2 in the presence of NaHCO3 led to a decrease of isolated cells and an increase of reaggregation with degeneration in the great clusters. When H2O2 and 5 mM HEPES were present together in the absence of NaHCO3, the aggregation was less than with HEPES alone. By use of a chemical defined medium DME/F-12 supplemented with Insulin, Transferrin, sodium selenite, bovine serum albumin and 15 mM HEPES both the number and the diameter of cell aggregates increased. Addition of 0.5% ethanol in the presence of NaHCO3 stimulated in cultures of the ganglion trigeminale and telencephalon (9 day chick embryos) the regeneration of neurites and the proliferation and migration of non-neural cells. No growth of neurites was observed on the same condition in brain cultures from 6 day chick embryo. The number of large aggregates increased significantly in the presence of NaHCO3 and in the chemical defined and supplemented medium DME/F-12. Bologa et al. (1987) demonstrated that the buffers TREA (Triethanolamine) and HEPES enhance the expression of properties related to post-mitotic differentiated cellular states in both neurons and glia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Evaluation of inflammatory reactions following cataract surgery].

Following cataract extraction 179 patients were examined with a slit-lamp using focal and specular illumination. 163 of them had received an intraocular lens (IOL). The cells (granulocytes) and flare-up in the anterior chamber decreased during the first postoperative days, while the cellular growth on the IOLs (macrophages) did not decrease in the same period. No correlations could be found between the cells, the flare-up in the anterior chamber, and the cellular growth on the IOLs. All three seem to be independent inflammatory reactions that occur following cataract extraction.

Anterior Chamber↗
PubMed1988

Preferential inhibition of 5-lipoxygenase activity by manoalide.

Treatment of human polymorphonuclear leukocytes (PMNLs) with micromolar concentrations of the anti-inflammatory drug manoalide inhibited production of leukotriene B4 (LTB4) and LTC4/LTD4 in response to the calcium ionophore A23187. In an attempt to further define the mechanism(s) of action of this agent, we have examined its interaction with several lipoxygenase enzymes. In RBL-1 cells, manoalide inhibited 5-lipoxygenase (5-LO) activity with an approximate IC50 of 0.3 microM. This was equipotent in our system with the known lipoxygenase inhibitor nordihydroguaiaretic acid (NDGA). Manoalide was virtually inactive, however, against 12-lipoxygenase activity in both human platelets and mouse epidermis, with little inhibition seen at concentrations up to 100 microM. Manoalide showed some activity against soybean lipoxygenase, although it was 30- to 50-fold less potent than as an inhibitor of the 5-lipoxygenase enzyme. These data indicate that manoalide is a selective 5-LO inhibitor and suggest the possibility that its anti-inflammatory actions may be due, at least in part, to inhibition of leukotriene synthesis.

Anti-Inflammatory Agents↗
PubMed1988

Cellular invasion on the surface of intraocular lenses. In vivo cytological observations following lens implantation.

Cellular growth on intraocular lenses can be observed by using a specular microscope. We examined in vivo the cellular pattern on the surface of implanted lenses during the early postoperative period in 63 patients. In every case inflammatory cells were noted on the lens surface at some point during the observation period. These often showed a spindle-like appearance resembling fibroblasts. The density of the cell population increased during the following days but usually did not exceed 100 cells/mm2. From the end of the first week, multinucleated giant cells may appear. In one case, a patient with a severe postoperative iritis and hypopyon demonstrated an extremely pronounced and long-lasting cellular proliferation.

Cataract Extraction↗
PubMed1988

[Ferrocene, ruthenocene and rhodocene analogs in haloperidol synthesis and organ distribution after labeling with 103Ru and 103mRh].

Ferrocene-Haloperidol was synthesized by N-alkylation of 4-(4'-chlorophenyl)- 4-hydroxypiperidine with 1-ferrocenyl-4-chlor-butan-1-on. By heating the ferrocene-haloperidol with 103RuCl3 the 103Ru-labelled ruthenocene-haloperidol was obtained. This compound showed a high affinity for lung but not for brain in rats and mice. The decay of the 103Ru labelled compound results in the formation of the 103mRh labelled rhodocene-haloperidol, which is rapidly oxidized by air to the corresponding rhodocinium-haloperidol. This compound can be separated by extraction and TLC.

Animals↗