Biomedical subjects

M Knorr

Publications and source records attributed to M Knorr.

At least 19 recordsLinked to original sources

PubMed2005

[Correlation between glaucomatous hemifield scotomas and measurements of nerve fiber layer thickness using scanning laser polarimetry].

BACKGROUND: The purpose of the present study was to investigate wether a reduction of the retinal nerve fiber layer (RNFL) in patients with hemifield scotoma can be measured with scanning laser polarimetry and wether regional RNFL parameters can be correlated with the corresponding visual field indices. PATIENTS AND METHODS: We included one eye from each of 40 normal subjects and one eye from each of 40 glaucoma patients. Automated perimetry was performed and the RNFL was analyzed. RESULTS: HMD values obtained by white-white (W/W) and blue-yellow (B/Y) perimetry failed to correlate significantly with most of the corresponding RNFL parameters obtained with the GDx. Significant correlations were only shown for the inferior HMD (W/W and B/Y) and the superior ratio, superior average, and deviation superior. Furthermore, we found a high correlation between differences of upper and lower GDx parameters and differences of upper and lower visual field indices of W/W and B/Y perimetry. CONCLUSIONS: Scanning laser polarimetry can detect differences in RNFL sectors in patients with functional hemifield differences and carries the potential to detect changes in RNFL thickness at an early stage.

Diagnosis, Differential↗

PubMed2002

[Differential regulation of expression of PDGF receptors on corneal epithelial cells].

BACKGROUND: The function of platelet-derived growth factor (PDGF) during corneal wound healing is only incompletely understood to date. Previous studies have shown that the mRNA of PDGF receptor type alpha (PDGFR alpha) and type beta (PDGFR beta) is expressed in cultured corneal epithelial cells (CEP). To add to the current knowledge, the following study was designed to compare the expression of mRNA and protein of both PDGF receptor subtypes in cultured CEPs and in CEPs ex vivo. METHODS: Total RNA and protein were extracted from cultured CEPs and from CEPs ex vivo according to standard protocols. The reverse-transcription polymerase chain reaction (RT-PCR) was applied to detect specific expression of the mRNA of PDGFR alpha and PDGFRss. The expression of the corresponding proteins was detected using Western blotting. RESULTS: MRNA and protein of both PDGF receptor subtypes could be detected in cultured CEPs but not in CEPs ex vivo. CONCLUSION: The present study shows for the first time that mRNA and protein of both PDGF receptor subtypes are expressed in cultured human corneal epithelial cells, while corneal epithelial cells ex vivo do not express these receptors. The differential up-regulation of PDGF receptors in activated cells during wound healing could be of pathophysiological importance.

Blotting, Western↗

PubMed2001

Clinical evaluation of twice-daily emedastine 0.05% eye drops (Emadine eye drops) versus levocabastine 0.05% eye drops in patients with allergic conjunctivitis.

PURPOSE: The efficacy and safety of emedastine 0.05% eye drops (Emadine; Alcon Laboratories, Inc, Fort Worth, Texas), a new H(1) antagonist, were studied in comparison to levocabastine 0.05% eye drops (Livostin; Janssen-Cilag N V, Berchem, Belgium) during a twice-daily treatment schedule for 6 weeks in adult and pediatric patients with seasonal allergic conjunctivitis. METHODS: In a prospective, multicenter, randomized, double-masked, parallel group study, 222 patients with allergic conjunctivitis were randomized (221 received treatment) to either emedastine or levocabastine, instilled twice daily for 6 weeks. Patient diaries were completed four times daily (before the morning and evening instillations, at noon, and in the afternoon), and clinical examinations were conducted at regular intervals. Primary efficacy variables of ocular redness and itching and secondary efficacy variables of chemosis, eyelid swelling, patient diary data, and physician's global assessment were analyzed. RESULTS: Both emedastine and levocabastine produced a statistically significant (P =.0001) reduction in itching and redness within 5 minutes of the first instillation. All signs and symptoms improved progressively over the 6-week treatment period. After 7 days of use, and throughout the remainder of the study, emedastine was statistically superior to levocabastine (P <.006) in preventing and alleviating the signs and symptoms (itching, redness, chemosis, and eyelid swelling) of allergic conjunctivitis. CONCLUSIONS: Emedastine 0.05% eye drops administered twice daily are more efficacious than levocabastine 0.05% eye drops in the prevention and treatment of the signs and symptoms of allergic conjunctivitis in adults and children of 4 years and above. Both emedastine 0.05% eye drops and levocabastine 0.05% eye drops were well tolerated.

Adolescent↗

PubMed2000

Novel metal-to-metal silyl-migration reactions in heterometallic complexes.

An unprecedented, intramolecular metal-to-metal silyl ligand migration reaction has been discovered in a series of phosphido-bridged iron-platinum complexes and which may be triggered by an external nucleophile. Thus, reaction of solutions of [(OC)3-(R1/3Si)Fe(mu-PR2R3)Pt(1,5-COD) (1a R1 = OMe, R2 = 3 = Ph; 1b R1 = OMe, R2 = R3 = Cy; 1c R1 = Ph, R2 = R3 = Ph; 1d R1 = Ph, R2 = R3 = Cy; 1e R1 = Ph, R1 = H, R3 = Ph) in CH2Cl2 with CO rapidly afforded the corresponding complexes [(OC)4Fe(mu-PR2R3)Pt(SiR1/3)-(CO)] (2a-e) in which the silyl ligand has migrated from Fe to Pt, while two CO ligands have been ligated, one on each metal. When 1a or 1c was slowly treated with two equivalents of tBuNC at low temperature, quantitative displacement of the COD ligand was accompagnied by silyl migration from Fe to Pt and coordination of an isonitrile ligand to Fe and to Pt to give [(OC)3-(tBuNC)Fe(mu-PPh2)Pt[Si(OMe)3](CNtBu)] (3a) and [(OC)3(tBuNC)-Fe(mu-PPh2)Pt[SiPh3](CNtBu)] (3c). Reaction of 2a with one equivalent of tBuNC selectively led to substitution of the Pt-bound CO to give [(OC)4-Fe(mu-PCy2)Pt[Si(OMe)3](CNtBu)] (4b), which reacted with a second equivalent of tBuNC to give [(OC)4Fe(mu-PCy2)-Pt[Si(OMe)3](CNtBu)2] (5b) in which the metal-metal bond has been cleaved. Opening of the Fe-Pt bond was also observed upon reaction of 3a with tBuNC to give [(OC)3(tBuNC)-Fe(mu-PPh2)Pt[Si(OMe)3](CNtBu)2] (6). The silyl ligand migrates from Fe, in which it is trans to mu-PR2R3 in all the metal-metal-bonded complexes, to a position cis to the phosphido bridge on Pt. However, in 5a,b and 6 with no metal-metal bond, the Pt-bound silyl ligand is trans to the phosphido bridge. The intramolecular nature of the silyl migration, which may be formally viewed as a redox reaction, was established by a cross-over experiment consisting of the reaction of 1a and 1d with CO; this yielded exclusively 2a and 2d. The course of the silyl-migration reaction was found to depend a) on the steric properties of the -SiR1/3 ligand, and for a given mu-PR2R3 bridge (R2 = R3 = Ph), the migration rate decreases in the sequence Si(OMe)3> SiMe2Ph> SiMePh2>>SiPh3; b) on the phosphido bridge and for a given silyl ligand (R1 = OMe), the migration rate decreases in the order mu-PPh2 >> mu-PHCy; c) on the external nucleophile since reaction of 1c with two equivalents of P(OMe)3, P(OPh)3 or Ph2PCH2C(O)Ph led solely to displacement of the COD ligand with formation of 11a-c, respectively, whereas reaction with two equivalents of tBuNC gave the product of silyl migration 3c. Reaction of [(OC)3-[(MeO)3Si]Fe(mu-PPh2)Pt(PPh3)2] (7a) with tBuNC (even in slight excess) occurred stereoselectively with replacement of the PPh3 ligand trans to mu-PPh2, whereas reaction with CO led first to [(OC)3((MeO)3Si)Fe(mu-PPh2)Pt(CO)-(PPh3)] (8a), which then isomerized to the migration product [(OC)4Fe(mu-PPh2)Pt[Si(OMe)3](PPh3)] (9a). Most complexes were characterized by elemental analysis, IR and 1H, 31P, 13C, and 29Si NMR spectroscopy, and in five cases by X-ray diffraction.

Journal Article↗

PubMed2000

Nasal, pulmonary and autoinhaled nitric oxide at rest and during moderate exercise.

OBJECTIVE: To investigate nasal nitric oxide (NO) excretion, pulmonary NO excretion, and autoinhalation of nasally released NO at rest compared with that during moderate exercise in smokers and non-smokers. DESIGN: Prospective observational study. SETTING: University laboratory. PARTICIPANTS: Fourteen healthy adult volunteers. INTERVENTIONS: Breathing of NO-purified air supplied via a tube system at rest and during a bicycle-ergometer workload of 60 Watt over a time of 10 min. MEASUREMENT AND RESULTS: We examined nasal and pulmonary NO excretion in smoking (n = 7) and non-smoking (n = 7) adult human volunteers. At rest, we measured constant nasal NO excretion rates of 311 +/- 89 nl/min for non-smokers and 261 +/- 142 nl/min for smokers (mean +/- SD, n.s.). During 60 W exercise, nasal NO release remained unchanged, while pulmonary NO excretion doubled compared with the rates at rest (non-smokers: 40 +/- 21 nl/min versus 23 +/- 14 nl/min, p < 0.05; smokers: 41 +/- 8 nl/min versus 22 +/- 8 nl/min, p < 0.05). The differences between smokers and non-smokers in nasal or pulmonary NO excretion were not significant. To determine the autoinhaled amount of nasally released NO, we also measured the NO concentration within the nasopharynx of five volunteers during nasal breathing. The average inhaled NO concentration was 17.8 +/- 3.1 ppb at rest and this decreased to 9.3 +/- 1.8 ppb during exercise of 60 W, while minute ventilation approximately doubled from 9 +/- 2 to 21 +/- 3 l/min. CONCLUSION: Our results demonstrate that moderate exercise increased exclusively pulmonary NO excretion. Nasal NO release, which is 10 times higher at rest, was not changed. The decrease in autoinhaled NO concentration during exercise results from dilution of the continuous nasal release by the increased respiratory gas flow. The individual NO release allows no conclusion about smoking habits.

Adult↗

PubMed2000

[Are filtering interventions in glaucoma patients with extensive visual field defects associated with a higher functional risk?].

BACKGROUND: We evaluated the prevalence of the loss of visual acuity due to loss of the central portion of the visual field and foveolar fixation in the first week after glaucoma filtering surgery. PATIENTS AND METHODS: We included 408 patients, in whom glaucoma filtering surgery was performed between January 1993 and April 1997 at the University Eye Clinic in Tübingen and who had completed 1-year follow-up examinations. The retrospective evaluation included preoperative, intraoperative and postoperative data. We excluded all patients who did not complete 1-year follow-up examinations (12 +/- 3 months), who have died during the 1-year follow-up, who had combined glaucoma and cataract surgery or in whom the Molteno implant procedure was performed. RESULTS: A total of 404 patients (99.3%) did not suffer loss of the central visual field and foveolar fixation in the first week after glaucoma filtering surgery. In 11 cases, loss of visual acuity > 2 dB was due to progressive lens opacification. One patient suffered from postoperative progression of his age-related maculopathy. In one patient (0.2%) progression of a preexisting relative central scotoma occurred immediately after the operation. Two patients (0.5%) suffered from loss of fixation and the central visual field immediately after glaucoma filtering surgery. CONCLUSIONS: Loss of the central visual field and central fixation immediately after glaucoma filtering surgery is a rare complication. Therefore, glaucoma filtering surgery can also be recommended for patients with advanced visual field defects.

Filtering Surgery↗

PubMed2000

[Does public access to defibrillators have a chance in Germany?--On the US model, legal considerations and justification].

PURPOSE: The introduction of public access to defibrillation via automated external defibrillators makes it possible to reduce the incidence of sudden cardiac arrest cases. Since they may expect civil and criminal liability after negligence causing damage, many German potential First Responders might hesitate to use an AED. METHODS: After we demonstrate the medical reasons and compare the legal situation of Public Access Defibrillation between the USA and Germany we analyse a possible hesitation of German First Responders. RESULTS: More than 30 states of the USA provide immunity from civil liability after a public access defibrillation followed by damage due to negligence. However, only an AED-trained US-First Responder is granted immunity from civil liability. In Germany there is no immunity from civil and criminal liability in case of public access defibrillation with damage caused by negligence. CONCLUSION: German law will not decrease any possible hesitation by First Responders. For a successful system of public access defibrillation, revision of the legal situation is mandatory.

Cardiopulmonary Resuscitation↗

PubMed2000

Selection and reversion of azamethipos-resistance in a field population of the housefly Musca domestica (Diptera: Muscidae), and the underlying biochemical mechanisms.

The organophosphorus insecticide, azamethiphos, is widely used throughout the world to control the housefly, Musca domestica (L.). Since its commercial introduction to Denmark in 1983 for this purpose, we have monitored the toxicity of azamethiphos to housefly populations at livestock farms throughout the country and carried out regular field studies. The findings of our field studies, which have revealed a strong potential for resistance development, have been born out by regular surveys showing that resistance has increased in recent years. Through the analysis of a field derived laboratory strain, we have implicated oxidative and hydrolytic mechanisms together with altered acetylcholinesterase in this resistance. Our field and laboratory studies have also indicated that resistance is relatively unstable, and can revert in the absence of selection. The implications of our findings for the continued efficacy of azamethiphos are discussed.

Acetylcholinesterase↗

PubMed2000

Cytokine regulation of hyaluronate production by human Tenon's capsule fibroblasts.

PURPOSE: The high-molecular weight glycosaminoglycan hyaluronate (HA), a component of the extracellular matrix, has been shown to play important roles in many biological processes including cell proliferation, migration and differentiation. In the present study, the effect of cytokines on production of hyaluronate (HA) by human tenon's capsule fibroblasts (HTF) was determined. METHODS: HTF (2(nd) passage) were seeded at a cell density of 30 cells/mm(2) and stimulated by six different cytokines (platelet-derived growth factor (PDGF)-AA, PDGF-BB, basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), interleukin (IL)-1beta and transforming growth factor (TGF)-beta1). Controls were treated with aliquots of serum-free medium only. Concentrations of HA were determined using a radiometric assay based on the specific binding of HA to HA binding proteins. RESULTS: The concentration of HA in conditioned medium of HTF was significantly increased only after stimulation with PDGF-AA [10 and 100ng/ml], IL-1beta [1 and 10ng/ml] and TGF-beta1 [5ng/ml]. CONCLUSIONS: Production of HA by HTF is regulated by PDGF-AA, IL-1beta and TGF-beta1 and is speculated to be involved in the wound healing reaction after glaucoma filtration surgery.

Becaplermin↗

PubMed1999

[Effect of lymphocyte-conditioned medium on expression of smooth muscle alpha-actin in lens epithelium cells in situ].

PURPOSE: Contraction of the capsule of the ocular lens is based upon proliferation and contraction of transformed lens epithelial cells. It is assumed that these processes can be assisted by postoperative intraocular inflammation. Previously, we reported that lens epithelial cell proliferation is enhanced by lymphocyte-conditioned medium (LCM). In this study we investigated the effect of LCM as well as of a culture medium conditioned by pigmented ciliary epitheilal cells (CBCM) on the expression of the smooth-muscle alpha-actin of the contractile cytoskeletal elements. METHODS: Explants of the anterior lens capsule of freshly enucleated bovine eyes were cultured in serum-free LCM and CBCM for 3 days, followed by fixation. Smooth-muscle alpha-actin was identified by indirect immunoflorescence. Explants cultured in serum-free bFGF-containing and TGF-beta containing medium served as control. RESULTS: Lens epithelial cells expressed smooth-muscle alpha-actin under the influence of LCM or TGF-beta. No smooth muscle alpha-actin could be detected under the influence of CBCM or bFGF. CONCLUSION: Our results demonstrate that secreted molecules of activated lymphocytes are able to induce the transformation of lens epithelial cells into contractile myofibroblasts and may be involved in the post-operative contraction of lens capsules.

Actins↗

PubMed1999

Inhibitory effect of Trapidil on the proliferation of bovine corneal fibroblasts in vitro.

BACKGROUND: In order to develop new strategies for the pharmacological modulation of posttraumatic and postsurgical wound healing of the corneal stroma, the effect of Trapidil, a competitive platelet-derived growth factor (PDGF) antagonist, on the proliferation of cultured bovine stromal fibroblasts (BSF) was investigated. METHODS: BSF, obtained from explant cultures, were seeded at a cell density of 100/mm2. The effect of various concentrations of Trapidil on cell viability and cell proliferation was determined using three different culture conditions: (1) serum-free medium (WM/F12), (2) serum-containing medium (WM/F12 + 10% FCS), and (3) serum-free medium + 50 ng/ml PDGF-BB. Trapidil was added in concentrations ranging from 100 micrograms/ml to 400 micrograms/ml. Cell numbers were determined 2 and 5 days after addition of Trapidil, using a computer-based cell-counting system. Cell viability was evaluated morphologically and by means of a repopulation assay. RESULTS: Addition of Trapidil (100-400 micrograms/ml) led to a significant, dose-dependent inhibition of both serum- and PDGF-BB-induced proliferation of BSF. In contrast, treatment of quiescent BSF, cultured in serum-free medium, did not result in a significant reduction of cell number. No cytotoxic effects were observed. CONCLUSION: The results of the present study demonstrate an inhibitory effect of Trapidil on the proliferation of BSF. It can be assumed that application of Trapidil might be a useful tool in the prevention of corneal complications after trauma (e.g., scarring, astigmatism and--with respect to photorefractive procedures--formation of haze and regression of the refractive effect).

Animals↗

PubMed1999

Effect of heparin on human corneal fibroblast proliferation in vitro with and without growth factor stimulation.

BACKGROUND: The outcome of keratorefractive procedures such as PRK and LASIK is limited by the wound-healing process in the corneal stroma, which gives rise to complications such as haze formation and regression. The proliferation and matrix synthesis of corneal stromal fibroblasts is the central element of the wound-healing process. In order to develop new therapeutic strategies to reduce wound-healing intensity, we investigated the effect of heparin on the proliferation of cultured human corneal stromal fibroblasts (HCF) alone and in the presence of growth factors. METHODS: Primary cultures of HCF were established using epithelium and endothelium-free explants. Secondary cultures of HCF (first passage), cultured in WM/F12 supplemented with 10 microg/ml transferrin and 10 microg/ml thyroglobulin (LR-1 medium), 1% fetal calf serum (FCS) and 10% FCS were used to determine the effect of heparin on the proliferation of HCF in concentrations ranging from 12.5 microg/ml to 5000 microg/ml. Cell number was determined using the CASY 1 cell counter system. Modulation of HCF proliferation by heparin (50 microg/ml and 2000 microg/ml) was also investigated under serum-free conditions and in the presence of bFGF, EGF and PDGF-BB. RESULTS: Addition of heparin led to a dose-dependent inhibition of proliferation after 6 days of incubation, which was statistically significant for 500-5000 microg heparin/ ml (FCS 1%) and for 200-5000 microg heparin/ml (FCS 10%). IC50 values for this effect were determined to be approximately 700 microg heparin/ml. When cultured under serum-free conditions (LR-1), a significant reduction of cell number was only observed with 5000 microg heparin/ml. There was no significant modulation of PDGF-BB-, bFGF-, or EGF-stimulated cell proliferation by heparin at concentrations of 50 microg/ml and 2000 microg/ml after 6 days of incubation. CONCLUSION: Our observations indicate that heparin can inhibit proliferation of HCF effectively. The results of the present study could eventually pave the way to prevent anterior stromal haze formation and regression after keratorefractive surgery.

Anticoagulants↗

PubMed1999

[Wound healing after glaucoma filtering surgery--a review].

Wound healing after glaucoma filtering surgery is characterized by a complex sequence of molecular and cellular events. Results of recent investigations have shown that the activation, migration, proliferation and differentiation of Tenon's capsule fibroblasts represents the central element of the wound healing response. An exaggerated wound healing will result in the closure of the artificial fistula between the anterior chamber and the subconjunctival space, leading to an increase in intraocular pressure. The present review summarizes the current knowledge regarding the most important cellular and molecular mechanisms, which regulate the postsurgical wound healing response in the subconjunctival space. Special emphasis will be put on the specific role of cytokines during the wound healing response. An extensive understanding of these mechanisms appears pivotal for the development of specific therapeutic strategies to inhibit the events which lead to fibrogenesis and scarring in the wound region after glaucoma filtration surgery. The databank was Medline.

Animals↗

PubMed1999

[Prognostic value of anterior chamber hemorrhage following glaucoma filtering surgery].

PURPOSE: Evaluation of the prognostic significance of a postoperative anterior chamber hemorrhage (ACH) after glaucoma filtering surgery. PATIENTS AND METHODS: Records of 332 patients, who had undergone filtering surgery between 1/1993 and 2/1997, were analyzed retrospectively with particular concern on epidemiologic data, pre- and postoperative regulation of intra-ocular pressure (IOP), complications including ACH, postoperative 5-fluouracil (5-FU) therapy and postoperative IOP lowering therapy. Surgical success was defined as (1) IOP reduction below 21 mm Hg, (2) relative IOP reduction at least 20% and (3) no reoperation to control IOP until the first-year examination. RESULTS: 60 out of 332 patients (18.1%) suffered from ACH after glaucoma filtering surgery. 24 patients with ACH were treated with 5-FU, postoperatively. When all patients with ACH were considered in the evaluation, the difference between the success rate of patients with ACH and the success rate of patients without ACH was not statistically significant. In contrast, when ACH was the only complication in patients, who were not treated with 5-FU, the success rate was significantly worse (38%), when compared with the control group (patients, who did not have ACH or who had other complications in addition to ACH) (67%) (p = 0.008). When patients with these criteria received 5-FU postoperatively, the difference between success rates of both groups was not any longer statistically significant (p = 0.99). DISCUSSION: The postoperative occurrence of anterior chamber hemorrhage is associated with a higher failure rate of filtering surgery. Early administration of 5-FU is recommended in these cases.

Aged↗

PubMed1999

Serum-free cultivation of human Tenon's capsule fibroblasts.

PURPOSE: In the present study, the effect of three different serum-free and one serum-containing control medium on adhesion, proliferation, cryopreservation and PDGF-induced effects on cell proliferation of human Tenon's capsule fibroblasts (HTF) was compared. MATERIALS AND METHODS: Third passage HTF were suspended in four different culture media (WM/F12, WM/F12/FCS 1%, LR-1, DMEM) and plating efficiency was determined after 24h using a cell counter system. Subsequently, cells were seeded at a density of 50/mm2 and cultured for ten days using the different culture media. Cell number was determined at day 2, 4, 7 and 10 after seeding. Furthermore, HTF cultured under the different conditions were stimulated by PDGF-BB [50 ng/ml]. Additionally, cell vitality after two weeks cryopreservation in five different culture media (WM/F12, WM/F12/FCS 1%, WM/F12/FCS 20%, LR-1, DMEM) was determined. RESULTS: The plating efficiency of HTF when seeded in serum-free medium ranged from 55.3% to 59.6%. Using serum containing WM/F12/FCS 1% a slightly higher plating efficiency of 74.8% was obtained. Proliferation assays revealed population doublings of 0.77 with WM/F12/FCS 1% after an incubation period of 10 days. Cultivation of HTF using serum-free conditions did not cause significant cell proliferation but a slight cell loss which ranged from 23.1% to 34%. Addition of PDGF-BB resulted in a significant increase in cell proliferation with WM/F12/FCS 1%, WM/F12 and DMEM. After two weeks of cryopreservation in WM/F12, LR-1, DMEM, WM/F12/FCS 1% and WM/F12/FCS 20%, only the application of high serum concentrations led to sufficient preservation of cell vitality with a plating efficiency of 82.9%. DISCUSSION: The results of the present study demonstrate that the use of serum-containing media is mandatory for cryopreservation of HTF. Seeding of cells can be performed either with serum or without serum. HTF cultured under serum-free conditions can be maintained quiescent with a sufficient number of cells remaining vital. The serum-free media used in this study can be applied for the investigation of cytokine effects on HTF.

Cell Adhesion↗

PubMed1998

[Serum-free cultivation of bovine stromal fibroblasts].

UNLABELLED: The purpose of the present study was to conduct a comparative evaluation of the effect of several serum-free culture conditions on adhesion, population doubling, cryopreservation and PDGF-induced effects on cell proliferation of bovine stromal fibroblasts (BSF). Additionally, these effects were compared to serum-containing cultures. METHODS: Only second-passage BSF were used. Cells were cultured using four different culture media (WM/F12, WM/F12 + FCS 1%, LR-1, DMEM). After 24 h, plating efficiency was determined using a cell-counter system. Subsequently, the cells were seeded at a density of 100 cells/mm2 and cultured for 10 days using the different culture media. Cell number was determined at day 2, 4, 7 and 10 after seeding. Furthermore, the effect of 50 ng/ml PDGF-BB on the proliferation of BSF was tested for these conditions. Cell vitality was determined after cryopreservation of two weeks for each culture medium. RESULTS: The plating efficiency of BSF ranged from 50.2 to 55.5% for the serum-free culture media in contrast to serum-containing conditions, where plating efficiency was 94.8%. With WM/F12 + FCS 1%, a population doubling of 1.27 was observed after an incubation period of 10 days. In contrast, cultivation under serum-free conditions caused neither significant cell proliferation nor cell loss. The stimulation of cell proliferation with PDGF-BB was shown to be 28% (LR1), 40% (WM/F12 + FCS 1%) 76% (WM/F12) and 95% (DMEM) compared to the control. While cell vitality after cryo-preservation was found to be 62.7% using WM/F12 + FCS 1%, vitality using serum-free media was 12.6-22.8%. CONCLUSIONS: The results of the present study demonstrate that with respect to optimal cell adhesion and cell vitality after cryo-preservation, serum-containing media should be used. BSF cultured under the serum-free conditions used in the present study can be maintained quiescent and vital for at least 10 days. Therefore, these serum-free media are useful for cell-culture studies (e.g., determination of proliferation and cytotoxicity).

Animals↗

PubMed1998

Argon laser therapy of benign tumors of the eyelid.

PURPOSE: To report the therapy of benign eyelid tumors with an argon laser as an alternative to surgery. METHODS: Forty-one patients with 47 benign tumors of the eyelid were included in this study. In all patients, the eyelid tumor was eliminated by argon laser. In 24 cases the lower eyelid and in 23 cases the upper eyelid was involved, including the lid margin in 17 cases. Laser spot size ranged from 150 to 500 microm. Argon laser power density varied between 4.1 and 61.1 W/mm2. Spots were counted between 40 and 1204. Twenty-seven of 41 patients treated were followed up; the mean follow-up period was 5.8 months (range, 3 to 24 months). Postoperatively, histologic confirmation was obtained in 42 cases of the 47 treated tumors. RESULTS: All patients were satisfied regarding the laser therapy and the cosmetic result. Remarkably, the wounds were dry after argon laser therapy. No infections of the wounds occurred; wounds were epithelialized after 2 to 3 weeks by a normal-appearing epithelium. The area of argon laser treatment was less pigmented than the surrounding skin and showed no obvious remarkable notches. As a complication, one patient developed a viral conjunctivitis. No relapses occurred during follow-up. CONCLUSIONS: Argon laser therapy of benign eyelid tumors may result in very satisfactory wound healing. Taking the short follow-up and the limited number of cases into account, it seems to be a useful alternative to traditional surgery, especially for tumors positioned close to the lacrimal papillae.

Adolescent↗

PubMed1998

Retinal plasma extravasation in animals but not in humans: implications for the pathophysiology of migraine.

High-intensity electrical stimulation of the trigeminal ganglion is accompanied by mast cell degranulation, vasodilatation, increased endothelial permeability and leakage of albumin from postcapillary venules within the dura mater. Overall, the histological appearance suggests an evolving sterile inflammatory response. This neurogenic inflammation within the meninges has been suggested as a model to explain the pain in migraine and cluster headache, and has been used to characterize the pharmacology of anti-migraine compounds. Using the rat model of neurogenic inflammation, the albumin extravasation ratio (stimulated : unstimulated side) in vehicle-treated animals in the dura and retina was 1.60 +/- 0.11 and 1.76 +/- 0.18, respectively (n = 10; values are mean +/- SEM). Pretreatment with sumatriptan (n = 9) produced a highly significant reduction in the ratio of extravasation within the dura to 1.10 +/- 0.06 (P = 0.002) and in the retina to 0.96 +/- 0.06 (P = 0.001), as did the neurokinin-1 receptor antagonist RP 67580 (n = 12) in the dura (1.04 +/- 0.11, P = 0.002) and retina (1.08 +/- 0.06, P = 0.001). These data demonstrate increased endothelial permeability and leakage of albumin not only in the dura but also in the retina. In a second stage we investigated possible extravasation in the human retina in acute migraine (n = 8) and cluster headache (n = 5) using fluorescein or indocyanine angiography. No increased endothelial permeability or leakage of dye could be found in the human retinal or choroidal vessels during headache attacks or in the headache-free interval in persons suffering from both migraine and cluster headache. These data raise the possibility that neurogenic inflammation is not a major factor in headache attacks in migraine or cluster headache.

Adult↗