[Limbo-conjunctival autografting in pterygium surgery]. / Autotransplantul limbo-conjunctival în chirurgia pterigionului.

PURPOSE: To evaluate the efficiency of the limbo-conjunctival autografting in pterygium surgery. MATERIALS AND METHODS: A study has been undertaken in two centers. The first one, which was a prospective observational one, went on for 20 months and included the patients operated with pterygium in the Ophthalmology Clinic in TgMures, RO. Two surgical techniques have been used: limbo-conjunctival autografting and the Arlt technique. The results of the two methods have been followed and compared, as well as the intra and post-surgery complications. The second study, a retrospective observational type of study, went on for 15 months and included the patients operated with pterygium in the Ophthalmology clinic in Debrecen, Hungary. We used 4 methods to treat the pterygium: the Arlt method, the McReynolds method, the sclero-corneal lamellar plasty and the limbo-conjunctival autografting. We analysed the obtained results using all these 4 methods. RESULTS: In the Ophthalmology Clinic in Targu-Mures we operated, during those 20 months, 106 patients with pterygium. Of these, 36 were operated using the limbo-conjunctival autografting, the rest using the Arlt technique. We noticed less relapse when the limbo-conjunctival autografting was used. In the Ophthalmology Clinic in Debrecen, during a 15 months period, there were 33 patients operated for pterygium. The largest number of relapses was noticed with the Arlt technique. CONCLUSIONS: When comparing the different methods used in the pterygium surgery in terms of relapse we noticed the increased efficiency of the limbo-conjunctival autografting. The encouraging results stimulate us in using and recommending this method.

Corneal pathology and indications for corneal transplant at the Tg. Mures Ophthalmology Clinic.

UNLABELLED: The purpose of this study was to evaluate the incidence of corneal pathology that presents indication for cornea/transplant, treatment and follow-up of these patients. MATERIALS AND METHODS: A retrospective analysis has been undertaken at the Tg. Mures Ophthalmology Hospital. In the study we have included all patients who had corneal pathology with intact deeper ocular structures. We have examined the treatment of these cases and their admittance to corneal transplantation. RESULTS: In 2008 in 99 cases of the 3246 hospitalized patients such a corneal condition has been described that presented indication for corneal transplantation. Most common causes were corneal leucomas, corneal ulcers, bullous keratopathy and corneal dystrophies and degenerations. Fourteen patients tried to benefit from corneal transplant abroad financed by the National Health Insurance Office; others went on their own expense. All together four patients appeared for postoperative control at our Hospital. CONCLUSIONS: We have found 99 cases of corneal transplant indication at our Hospital's patients and only a fraction of them have undergone surgery. We can point out a very low level of admittance and a great need for a regional corneal transplantation centers.

Comparison of divide and conquer and phaco-chop techniques during fluid-based phaco-emulsification.

PURPOSE: To determine whether, similar to ultrasound phaco-emulsification, applied energy and surgery time decrease using phaco-chop nucleus fragmentation method compared to divide and conquer technique using the fluid-based system. METHODS: This prospective, comparative, randomized clinical study included patients with cataract who were randomly assigned to use either standard divide and conquer technique (25 eyes of 25 patients, Group 1) or Nagahara phaco-chop maneuver (25 eyes of 25 patients, Group 2) during fluid-based phaco-emulsification. Surgical parameters were recorded and patients were examined 1 day, 10 days, and 1 month after surgery. Statistical analyses were performed using the paired test of Wilcoxon. RESULTS: Fluid-based time, mean fluid-based magnitude, effective fluid-based time, and the number of pulses were significantly less using phaco-chop technique compared to divide and conquer method (p<0.001). Surgery time was similar using the two nucleofractis techniques (p=0.97). Visual acuities showed no statistical differences between the two groups (p>0.05). CONCLUSIONS: Nuclear fragmentation can be performed with Nagahara phaco-chop technique using the fluid-based system as well. The applied fluid-based energy decreases compared to divide and conquer method. However, surgery time is not reduced due to the difficulties reaching the full occlusion necessary to hold the nucleus during the chop maneuver.

Ophthalmic Findings in Patients After Renal Transplantation.

The aim of the study was to perform complete ophthalmic examinations in patients after renal transplantation to determine ocular alterations and condition of the eyes. Moreover, ophthalmic findings were correlated with certain clinical characteristics related to transplantation such as post-operative renal functions and immunosuppressive regimen. The study was performed on 84 eyes of 42 patients who had received a renal transplant at least 6 months earlier. All patients underwent a complete ophthalmologic examination. In addition, in 33 (78.6%) patients peripapillary retinal nerve fiber layer (RNFL) thickness was determined using optical coherence tomography (Stratus OCT, Zeiss, Germany), which is a unique finding among renal transplantation patients. Recipients received immunosuppressive therapy consisting of tacrolimus, mycophenolate mofetil, and corticosteroid. Of 42 patients, 19 (45%) were women and 23 (55%) were men. The age of the patients ranged from 26 to 74 years, the mean age was 53.4 years. At least one ocular abnormality could be detected in 37 patients (88%), including impaired visual acuity (n = 31, 74%), keratoconjunctivitis sicca (n = 6, 14.3%), pinguecula (n = 3, 7.1%), arcus lipoides (n = 1, 2.4%), cataracts (n = 24, 57.1%), glaucoma (n = 2, 5%), retinal drusen (n = 6, 14.3%), and hypertensive or atherosclerotic retinopathy (n = 22, 52.4%). Twenty-five patients (75.8%) have reduced RNFL thickness. Cataract formation was positively correlated with age and usage of methylprednisolone. Moreover, RNFL thickness loss was correlated with transplantation duration and postoperative infections. Our study suggests that ocular disorders are frequent among renal transplantation patients. Besides immunosuppression and postoperative infection, aging is a high-risk factor in such cases.

The expression pattern of hyaluronan synthase during human tooth development.

In previous studies, hyaluronan (HA) and its major cell surface receptor CD44 have been suggested to play an important role during tooth development. HA synthases (HASs) are the enzymes that polymerize hyaluronan. Data on the expression pattern of HASs during tooth development is lacking and the aim of the present study was to investigate the localisation of HAS by immunohistochemistry in human tooth germs from different developmental stages. The distribution pattern of HAS in the various tissues of the "bell stage" tooth primordia corresponded to that of hyaluronan in most locations: positive HAS immunoreactivity was observed in the dental lamina cells, inner- and outer-enamel epithelium. On the stellate reticulum cells, moderate HAS signal was observed, similar to the layers of the oral epithelium, where faint HAS immunoreactivity was detected. At the early phase of dental hard tissues mineralization, strong HAS immunoreactivity was detected in the odontoblasts and their processes, as well as in the secretory ameloblasts and their apical processes and also, the pulpal mesenchymal cells. The HAS signals observed in odontoblasts and ameloblasts gradually decreased with age. Our results demonstrate that hyaluronan synthesised locally by different dental cells and these results provide additional indirect support to the suggestion that HA may contribute both to the regulation of tooth morphogenesis and dental hard tissue formation.

Accuracy of in vivo carotid B-mode ultrasound compared with pathological analysis: intima-media thickening, lumen diameter, and cross-sectional area.

BACKGROUND AND PURPOSE: This study aimed to determine the correlation of in vivo ultrasound measurements of intima-media thickening (IMT), lumen diameter, and cross-sectional area of the common carotid artery (CCA) with corresponding measurements obtained by gross pathology and histology. METHODS: Sixty-six moribund neurological patients (mean age 71 years) underwent B-mode ultrasound of the CCA a few days before death. During autopsy, carotid specimens were removed in toto. Carotid arteries were ligated and cannulated for injection of a hydrophilic embedding material under standardized conditions. The carotid bifurcation was frozen and cut manually in 3-mm cross slices. Digital image analysis was carried out to determine the diameter and the cross-sectional area of the frozen slices of the CCA. IMT was assessed by light microscope. Ultrasonic and planimetric data were compared. RESULTS: Mean measurements of lumen diameter and cross-sectional area were 7.13+/-1.27 mm and 0.496+/-0.167 cm(2), respectively, by ultrasound, and 7.81+/-1.45 mm and 0.516+/-0.194 cm(2), respectively, by planimetric analysis of the unfixed redistended carotid arteries (R(2)=0.389 and 0.497). The mean IMT was 1.005+/-0.267 mm by ultrasound and 0.67+/-0.141 mm histologically, resulting in a mean difference of -31%. CONCLUSIONS: Transcutaneous B-mode ultrasound provides a reliable approach for in vivo measurements of the cross-sectional area and, less exactly, of the lumen diameter of the CCA. Compared with histological results, in vivo ultrasound measurements of the IMT are systematically larger.

The zonal expression of chicken cartilage matrix protein gene in the developing skeleton of transgenic mice.

Cartilage matrix protein (CMP) is a major noncollagenous glycoprotein of hyaline cartilage with a molecular mass of about 148 kDa. It has been proposed to be involved in matrix organization by its interactions with proteoglycan and type II collagen. The 54-kDa monomers form homotrimers stabilized by disulfide bonds. The gene for chicken cartilage matrix protein was isolated, and its regulation has been studied recently in transient expression experiments. To learn more about the spatial and temporal expression of the gene during ontogenic development, we created transgenic mice via microinjection of a 21.8-kb genomic fragment, encoding the chicken cartilage matrix protein. None of the founder animals exhibited any abnormal phenotype. The developmental stage-specific expression of the transgene was examined by immunostaining with a chicken CMP specific antiserum at different stages of embryonic development in cartilage from different sources: lower and upper limb, vertebrae, ribs and nasal septum. The level of transgene expression showed marked differences in various zones of cartilage. Briefly, high levels were found in the zones of proliferating chondrocytes, while little if any transgene product was detected in the very early and hypertrophic stage of chondrogenesis. The expression pattern of the transgene correlated with the endogenous mouse CMP and did not cause any morphological changes detectable by microscopic analysis of cartilage. These data indicate that the injected CMP gene with its flanking sequences contained all the information necessary for cell type-specific expression in transgenic mice.

Factor XIII of blood coagulation as a nuclear crosslinking enzyme.

Intracellular localization and distribution of Factor XIII subunit A (FXIIIA) was investigated in association with monocyte-macrophage differentiation in a long term culture of human monocytes by light- and electron microscopical as well as biochemical and immunobiochemical techniques. To allow the detection of FXIIIA in cells with well-preserved ultrustructure, immunosera against glutaraldehyde-derivatized recombinant FXIIIA were developed in rabbits, then characterized and used in this study. In the early phase of macrophage differentiation intranuclear accumulation of FXIIIA was detected as a transient phenomenon in cells of the 2nd day culture by optical sectioning with 0,7 microm steps in laser scanning confocal microscopy and immunoblotting technique. FXIIIA could be detected by immunoelectron microscopic postembedding staining over electrodense DNA-containing areas. Fluoresceinated monodansylcadaverine incorporation assay was used to demonstrate that FXIIIA is not only present in the nuclei, but also expresses its transglutaminase activity. Our finding of the nuclear accumulation of FXIIIA in differentiating human macrophages is also unique in that a blood clotting factor has, for the first time, been localized in nuclei and has been shown to be an intracellular crosslinking enzyme. The possible role of nuclear FXIIIA in association with cellular processes involving chromatin structure remodeling, such as cell death, cell differentiation or cellular proliferation requires further in-depth investigation.

Combination of digital image analysis and polarization microscopy: theoretical considerations and experimental data.

The potentialities of polarization microscopy has been greatly increased by using specific stains for selective enhancement of the optical anisotropy of a macromolecular constituent of cells and tissues. Such stainings have proved to be especially useful in exploring the spatial orientation pattern of the extracellular matrix components. The retardation value, which characterizes quantitatively the degree of submicroscopic orientation, can be measured traditionally with a compensator plate. This technique, however, is time-consuming and greatly dependent on visual judgment. Several attempts have been made to combine digital image analysis and polarization microscopy to improve the measuring technique in unstained structures. In this paper, we summarize theoretical considerations and experimental data to show the advantages and limitations of this methodological approach when using stained and birefringent specimens. The technique we are suggesting is the measurement of the light intensity using a 12 bit cCCD camera attached to a polarized light microscope and digital image analysis system. The theoretical basis is given by the Fresnel equation describing the relationship between light intensity and retardation value. According to this, there is a sin2 function between the light intensity and the retardation value. The same relationship of these two parameters was observed in our experiments on the birefringent extracellular matrix around chondrocytes grown in agarose gel and interterritorial and territorial matrix of canine articular cartilage stained with picrosirius red. Our results suggest that the retardation values can be calculated directly from the light intensity values if the retardation value is lower than lambda/2.

Corneal thickness measurements with contact and noncontact specular microscopic and ultrasonic pachymetry.

PURPOSE: To evaluate the central corneal thickness values in normal and postkeratoplasty corneas with the new Topcon SP-2000P noncontact specular microscopic, contact specular microscopic, and the "common standard" ultrasonic pachymetry. METHODS: Central corneal thickness was determined in 119 eyes of 81 patients (73 normal eyes of 44 patients and 46 eyes after penetrating keratoplasty) first with a noncontact specular microscopic (Topcon SP-2000P; Topcon Corporation, Tokyo, Japan), then an ultrasonic (AL-1000; Tomey, Erlangen, Germany), and finally with a contact specular microscopic (EM-1000; Tomey, Erlangen, Germany) pachymetry two times each by the same investigator. RESULTS: Reliability of the central corneal measurements was equally high both in normal and in postkeratoplasty corneas with all of the instruments (Cronbach alpha = 0.99). Noncontact specular microscopic corneal thickness determination correlated significantly both with ultrasonic (r =.86, P <.0001) and contact specular microscopic pachymetry (r =.62, P <.0001). The ultrasonic pachymetry correlated well with the Tomey pachymetry (r =.69, P <.0001). The Topcon normal mean central corneal thickness value (542 +/- 46 microm) was 28 +/- 4 microm lower (P <.0001) compared with the ultrasonic data (570 +/- 42 microm), which was 68 +/- 1 microm lower (P <.0001) compared with Tomey thickness (638 +/- 43 microm). CONCLUSIONS: Central corneal thickness measurements with noncontact specular microscopic, contact specular microscopic, and ultrasonic pachymetry demonstrate that each of the instruments is reliable but cannot be simply used interchangeably.

Serious fireworks-related eye injuries.

OBJECTIVE: To analyze and compare epidemiological and clinical information on serious fireworks-related eye injuries from two affiliates of the United States Eye Injury Registry. METHOD: Retrospective review. RESULTS: In the Eye Injury Registry of Alabama (EIRA) database, 185 of the 4150 injuries (4.4%) were caused by fireworks. In the Hungarian Eye Injury Registry database, only two of the 1245 cases (0.1%, p=0.000001) were fireworks-related. In the EIRA, 79% of patients were males and 87% were under 31 years. A bystander was injured in 67% of the cases, being an average of 23 feet away; 39% of bystanders had a final vision < or =19/200. No injured person wore eye protection. Bottle rockets caused 80% of the 185 injuries. Overall, 20% of eyes had <5/200 final visual acuity. Twenty-five percent of bottle rocket-injured eyes, compared to 64% of those injured by other devices, had > or =20/40 final vision (p=0. 000004). CONCLUSIONS. The rate of fireworks-related serious eye injuries has not decreased in Alabama in the last 16 years; most patients are young males. Since bystanders are at a measurable risk even at a distance of 100 feet, wearing eye protection is recommended to both bystanders and operators. Bottle rockets cause most of the injuries and the more severe ones, and should be the prime target for prevention. The benefit of a strict and enforced legislative ban on private fireworks displays is demonstrated by the much lower incidence figure in Hungary. Such a ban should be considered in other countries where fireworks-related eye injuries are common.

Scanning-slit and specular microscopic pachymetry in comparison with ultrasonic determination of corneal thickness.

PURPOSE: To determine the central corneal thickness values in healthy eyes with the recently developed Orbscan scanning-slit system, contact and noncontact specular microscopic pachymetry and compare the results to conventional ultrasonic pachymetry. METHODS: In the following sequence, Orbscan, Topcon SP-2000P noncontact specular microscope, AL-1000 ultrasound, and Tomey contact specular microscope were used to record thickness values. Thirty-four healthy right corneas of 34 healthy subjects were investigated. RESULTS: Orbscan pachymetry correlated significantly with ultrasound (r = 0.64, p < 0.001), contact (r = 0.45, p < 0.001), and noncontact specular microscopy (r = 0.72, p < 0.001). Likewise, the Topcon SP-2000P noncontact specular microscopy pachymetry disclosed similar statistical results compared with ultrasound (r = 0.88, p < 0.001), and contact specular microscopy pachymetry (r = 0.76, p < 0.001). The mean central corneal thickness results were significantly higher ( p < or = 0.01) than ultrasonic values (580 +/- 43 microm) using the contact specular microscope (640 +/- 43 microm) or Orbscan system (602 +/- 59 microm) but were significantly lower ( p < 0.001) using the noncontact specular microscope (547 +/- 49 microm). CONCLUSIONS: The results indicate that the devices tested cannot be simply used interchangeably. For long-term patient follow-up, one specific instrument is recommended. Recently developed pachymetry machines are especially helpful when additional corneal data such as thickness profile, elevation maps, anterior chamber depth, and endothelial morphology are required.

Expression of betaig-h3 is lower than normal in keratoconus corneas but increases with scarring.

PURPOSE: Keratoconus is a progressive ectatic disease of the cornea. Despite extensive clinical and laboratory investigations, its pathogenesis remains unclear. In this study, we examined the localization of betaig-h3, a recently described extracellular matrix protein in keratoconus corneas both in the absence and presence of subepithelial scarring. METHODS: Two normal corneas and central corneal buttons of 10 patients with keratoconus were excised during perforating keratoplasty and examined, including one case with acute corneal hydrops. In one case, keratoconus was associated with Down syndrome. Immunodetection was done with an antipeptide antibody reacting with the N-terminal part of betaig-h3. RESULTS: We found decreased betaig-h3 levels in the basal epithelial layer and keratocytes of keratoconus corneas. In the scarred corneas, however, betaig-h3 levels were increased in the basal epithelial layers and in activated keratocytes at the places of scarring. In the cornea of the patient with Down syndrome, we found an additional betaig-h3-positive zone in the anterior stroma. CONCLUSIONS: The decreased levels of betaig-h3 corneas seem to be specific for keratoconus. Considering the putative role of betaig-h3 as a cellular-attachment protein, paucity of betaig-h3 in the corneal stroma may lead to decreased mechanical stability and contribute to the development of keratoconus.

Cell surface glycoconjugates and the extracellular matrix of the developing mouse embryo epicardium.

Cell surface glycoconjugates and the extracellular matrix (ECM) of the proepicardium and the developing epicardium were studied in early mouse embryos by light and electron microscopy with histochaemical and immunocytochaemical techniques. The extracardially located proepicardium consists of polarized mesothelial cells forming the proepicardial vesicles. These vesicles contain a fine proteoglycan network and an acellular ECM rich in hyaluronic acid. Membrane-bound glycoconjugates are shown with cuprolinic blue, alcian blue and ruthenium red on the apical (outer) cell surface, while fibronectin and laminin are present on the basal (luminal) cell surface. These membrane and matrix components of the proepicardium might be involved in specific attachment of proepicardial cells to the bare heart tube and might facilitate the initial migration of epicardial cells over the myocardial surface. In the cell coat of the cardiomyocytes of the bare heart tube the fibronectin and laminin are concentrated in patches. The formation of the epicardial covering is a rapid process, requiring only about 2 days (9-11 days) to ensheath the entire heart tube from the inflow to the outflow segment. The subepicardial matrix between the newly formed epicardial covering and myocardial layer is acellular at first, but contains a condensing proteoglycan network, membrane and matrix fibronectin, type IV collagen and laminin on the myocardial cell surface. The formation and the distribution of the subepicardial ECM show regional characteristics. The accumulating ECM forms wide subepicardial spaces and protuberances in the atrioventricular and interventricular sulci. The sulci of the heart seem to provide the optimum microenvironment for haematopoiesis and vasculogenesis. Haematopoietic islands and coronary vessel forerunners appear and concentrate in the regularly spaced surface protuberances. The vasculogenesis proceeds from the inflow to the outflow segment of the heart. The first blood capillaries appear in the sinoatrial sulcus of the 10-day embryo. By 11-13 days the subepicardial blood vessels form an interconnected network and establish the coronary artery orifices.

Okadaic acid-induced inhibition of protein phosphatase 2A enhances chondrogenesis in chicken limb bud micromass cell cultures.

The role of major cellular serine/threonine-specific protein phosphatases, protein phosphatase 1 and 2A, was investigated during chicken cartilage differentiation under in vitro conditions. Activity of protein phosphatase 2A decreased parallel to differentiation of chondrogenic cells, whereas activity of protein phosphatase 1 remained unchanged as assayed in the supernatants of the homogenised chicken limb bud micromass cell cultures. When okadaic acid, a potent inhibitor of protein phosphatase 1 and 2A was applied in 20 nM concentration for 4 h during the second and third culturing days, it significantly increased the size of metachromatic cartilage areas measured in 6-day-old colonies. Following okadaic acid treatments, a significant inhibition in the activity of protein phosphatase 2A was found, while the activity of protein phosphatase 1 was unaffected as measured an days 2 and 3. TRITC-phalloidin labelling demonstrated that okadaic acid disorganised actin filaments and induced rounding of chondrogenic cells. This deterioration of actin filaments was reversible. Electron microscopy and biochemical analysis of colonies revealed that the ultrastructure and major components of cartilage matrix remained unchanged under the effect of okadaic acid. Okadaic acid-treatment applied to cultures containing predominantly differentiated chondrocytes (after day 4) did not influence the cartilage formation. 3H-thymidine and bromodeoxyuridine incorporation-assays demonstrated enhanced cell proliferation in the okadaic acid-treated colonies compared to that of the untreated ones. Our results indicate, for the first time, that protein phosphatase 2A is involved in the regulation of chondrogenesis. Inhibition of protein phosphatase 2A with okadaic acid may result in increased chondrogenesis via modulation of proliferation and cytoskeletal organisation, as well as via alteration of protein kinase A-signaling pathway of the chondrogenic cells.

The distribution pattern of the hyaluronan receptor CD44 during human tooth development.

The aim was to investigate the expression pattern of the major cell-surface hyaluronan receptor CD44, as there are no existing data on its presence or absence in human dental structures at different developmental stages. Immunohistochemical localization of CD44 was studied using a monoclonal antibody, H3, that specifically recognizes an epitope in the common backbone of all CD44 isoforms. The dental lamina displayed a strong CD44 signal; the external enamel epithelium was negative. In the coronal region of the tooth germ the presecretory ameloblasts showed an intense reaction whereas the less differentiated inner enamel epithelial cells showed no signal at the cervical loop where they meet the external enamel epithelium. In the stellate reticulum a moderate reaction was detected. The secretory ameloblasts and the stratum intermedium showed a strong cell-surface CD44 signal. A strong signal was also observed on the odontoblasts and their processes. In the pulp, close to the odontoblastic layer, weak labelling was seen in the walls of capillary vessels. The distribution of CD44 in the human tooth germ corresponds to that of hyaluronan in most locations, suggesting that during tooth development this transmembrane protein plays an important part in hyaluronan-mediated events.

Expression of aquaporin isoforms during human and mouse tooth development.

Previously, we described the development of hyaluronan (HA) deposition in human tooth germ tissues that are consistent with water transport in different stages of tooth development. The aquaporins (AQP) constitute a family of membrane water channels that are expressed in many organs. However, there are no data available about the expression pattern of aquaporin water channels in dental structures. In the present study we have characterised the expression of six different aquaporin isoforms (AQP1-5, AQP-9) in developing human and mouse tooth germs by immunohistochemistry using isoform specific antibodies. In the "bell stage" AQP1 was expressed in endothelial cells of small vessels whereas no other structures of the tooth primordial were labeled. AQP2, AQP3 and AQP9 immunoreactivity was not observed in tooth germs, whereas strong AQP4 and AQP5 expression was observed in dental lamina, inner enamel epithelium, stratum intermedium, stellate reticulum and the outer enamel epithelium. Oral epithelium also exhibited AQP4 and AQP5 immunolabeling. During development of the matrices of the dental hard tissues AQP4 and AQP5 immunostaining was observed in the odontoblasts and their processes, as well as in the secretory ameloblast and their apical processes. Immunolabeling controls were negative. In conclusion, AQP4 and AQP5 are expressed in tooth germ tissues in early development in cells that previously have been shown to express HA and/or CD44, indicating that AQP water channels may play a role for ECM hydration during tooth development.

Exogenous glycosaminoglycans modulate chondrogenesis, cyclic AMP level and cell growth in limb bud mesenchyme cultures.

Effects of hyaluronate, heparin and chondroitin-6-sulfate were studied on micromass cultures of chick limb bud mesenchyme (Hamburger and Hamilton stages 23-24). Histochemical, electron microscopical, biochemical and radiochemical investigations of day 4 cultures revealed dose-dependent inhibitory effects of these glycosaminoglycans on chondrogenesis, cyclic AMP level and growth of cells. In addition, hyaluronate with 100 micrograms/ml dose caused a displacement of newly formed proteoglycan from cultures into the medium. It is supposed that exogenous glycosaminoglycans influence ionic equilibrium in the immediate vicinity of cells and disturb the organization of the prechondrogenic extracellular matrix resulting in alterations of cell membrane--cytoskeleton associations. These alterations may provoke a reduction in cyclic AMP level and DNA synthesis. It is suggested that a reduction in cyclic AMP level preceding the expression of cartilage phenotype results in the inhibition of chondrogenesis.

[The evidence of POZ on the xenogenic transplantation of skin (author's transl)]. / Der Nachweis von POZ bei der xenogenen Hauttransplantation.

Phenoloxidase containing cells (POZ) identified with histochemical techniques in the subcutaneous connective tissue showed a marked increase in their number in response to heteroplastic skin transplantation in the rat. The number of these cells reached a peak of the 6th day of transplantation. From this time on their number gradually decreased on the 14th as well. POZ never invaded the graft, they remained confined to the host's tissue. A similar proliferation of POZ was never observed in the vicinity of skin autografts. The possible role in immune reactions of these cells is discussed.

[Behavior of phenoloxidase-containing cells in experimental granuloma]. / Zum Verhalten der Phenoloxidase enthaltenden Zellen (POZ) beim experimentellen Granulom.

Using the histochemical method for phenoloxidase (PO) in albino rats, the development of carrageenan granuloma was investigated. It is shown that especially those cells containing the methanol resistent PO activity are the cells which were be found during the formation of the granuloma. These findings support our earlier suggestion that POC are involved in the defence reactions.