Prediction studies of environment-friendly biodegradable polymeric packaging based on PLA. Influence of specimens' thickness on the hydrolytic degradation profile.

Application of new biodegradable polymer packaging based on polylactide (PLA), susceptible to organic recycling, can help in the waste reduction in landfills. In this paper, the results of the study on abiotic degradation of PLA and its blend containing 15 mol% of poly[(R,S)-3-hydroxybutyrate], as a model for the first step of organic recycling were presented. The samples used for this study have different shapes and thicknesses: rigid films and cuboid-bars. Particular emphasis was placed on determining the pattern of degradation products released into the medium. Originally, the results of present study revealed that the application of electrospray ionization mass spectrometry supported by high performance liquid chromatography allowed envisaging the differences in the degradation products pattern released from the studied PLA-based samples differing in thickness. The significant differences in degradation products pattern were predominately observed in the first steps of incubation process and are caused by an autocatalytic effect, which occurs mainly during degradation of the large size PLA samples. Although, the thickness of PLA-based packaging changes the degradation product patterns, however this does not increase the total amounts of acids released to the medium. Thus, it may be concluded that thickness should not affect significantly organic recycling of the packaging.

[Uvetitis and multiple sclerosis]. / Uveitida a roztrousená skleróza mozkomísní.

AIM: To evaluate the type of uveitis, the time of the duration between the first ocular signs and establishing of the diagnosis of multiple sclerosis (MS), effect of the treatment, and the final visual acuity (VA). METHODS: In a retrospective study, medical records of 41 patients (82 eyes) from the total of 1267 patients with uveitis treated at the Center for uveitis diagnosis and treatment at the Department of Ophthalmology of the Faculty Hospital and 1st Medical faculty, Charles University in Prague, Czech republic, during the period 1986-2003 were evaluated. The cohort consisted of 32 females and 9 males, mean age of 27 years (8-46 years). The mean follow-up period was 8 years (1-17 years). RESULTS: The cohort consisted of 41 patients (82 eyes), 32 females and 9 males. The mean age at the beginning of the uveitis was 27 years, at the time of the diagnosis of the MS 29.5 years. In 19 patients the starting of the uveitis preceded the manifestation of the systemic disease. In 23 patients, the uveitis was the first manifestation of MS. The most common type of uveitis in patients with MS was the intermediate uveitis (IMU) and vasculitis of retinal vessels. In 82% of patients, we were able during the follow-up period to stabilize the VA, or even to improve it. The systemic immunosuppressive treatment was necessary in 83 % of patients. SUMMARY: The MS was the second most common systemic disease in uveitis patients. It is necessary to follow-up young patients with unclear etiology of IMU or vasculitis, because the systemic disease may develop even few years after the first sings of uveitis. The collaboration between the neurologist and the ophthalmologist is of a great importance.

[Perforating pars plana sclerotomy in idiopathic uveal effusion syndrome]. / Perforující pars plana sklerotomie u syndromu idiopatické uveálni efúze.

PURPOSE: To evaluate anatomical and functional results of perforating pars plana sclerotomy in 2 patients with the idiopathic uveal effusion syndrome (IUES). METHODS: In two patients with IUES the perforating pars plana sclerotomy was performed. During the surgery samples of the suprachoroidal fluid for biochemical analysis of protein fractions were taken. RESULTS: During the follow-up period (average 4 years) the retina and the choroid attached, and the central visual acuity (VA) improved as well in both patients. CONCLUSION: In IUES, the conservative treatment is not effective. Perforating pars plana sclerotomy is treatment of choice and it had positive anatomical and functional effect in both our patients with IUES.

[The frosted retinal vascular branch syndrome]. / Syndrom omrzlých vetví retinálních cév.

In January 2002, thirty-eight years old healthy man with unusual clinical signs of vasculitis was examined in the Center for Diagnosis and Treatment of Uveitis in our Department of Ophthalmology. The patient had a flu-like disease one month before the signs of the eye disease started. In the beginning of the disease, the visual acuity (VA) was 6/12 (20/40 or 0.5) for distance and Jaeger 8 for near and 6/6 (20/20 or 1.0) and Jaeger 1 respectively. The clinical appearance was similar to this of frosted branch angiitis. The thorough medical examination did not discover link between vasculitis and any systemic disease. Serologic examination discovered positivity of IgG immunoglobulin antibody against cytomegalovirus (CMV) only. The intraocular fluid sampling to confirm CMV antibody presence was denied by the patient. After starting the treatment with gancyclovirus and corticosteroids, the considerable improvement of clinical signs of the frosted branch angiitis was noticed. VA improved after five days of treatment. During one-year follow-up, neither recurrence of vasculitis nor the decline of VA of both eyes was marked. In Czech ophthalmologic literature, we did not find any article referring to frosted branch angiitis, so we took the liberty of offering the Czech term "syndrom omrzlých vetví retinálních cév".

[Intraocular lymphoma--a clinical study of 14 patients with non-Hodgkin's lymphoma]. / Nitroocní lymfom--klinická studie 14 pacientu s NHL.

AIM: To evaluate the course of clinical picture of intraocular lymphoma, possibilities of examination of this disease and the association with general symptoms of the non-Hodgkin lymphoma (NHL) in patients with manifestations of uveitis. PATIENTS AND METHODS: A retrospective study in 14 patients followed in the period of 1996-2001 in the Center for Diagnostics and Therapy of Uveitis, Ocular Clinic of General Faculty Hospital and 1st Medical Faculty, Charles University in Prague. RESULTS: The group included 7 women and 7 men at the average age of 57.3 years (18-82) with clinical picture of uveitis. The time period from the first symptoms to the diagnosis of NHL was 5-38 months (mean, 14.6 month). In two patients the diagnosis of systemic NHL preceded ocular symptoms, in four other patients the diagnosis of systemic or central nervous system NHL (CNS NHL) was established during ocular manifestations of uveitis. Intraocular lymphoma was the only first manifestation of CNS NHL in six patients for the period of 9-34 months (mean, 15.2). Two patients have been so far affected by primary intraocular lymphoma (PIL) for 8 and 14 months respectively, and presently do not display any signs of systemic or CNS NHL. Clinical signs of intraocular inflammation of both eyes were encountered in 71.4% of patients. Vitritis (85.7%) and tumor infiltration of retina (65.3%) were the most frequent manifestations of NHL. Intraocular NHL was diagnosed on the basis of cytological examination of samples of intraocular fluids in 8 patients (57.1%). In four patients radiotherapy was applied onto 5 eyes and in 5 patients radiotherapy of CNS was used. Nine patients were treated with chemotherapy. 50% of patients died until the end of 2001, the survival from the establishment of diagnosis was 20.6 months on the average. CONCLUSIONS: Intraocular lymphoma should be considered as the eye and life-threatening disease. Cytological examination of intraocular fluids in patients with uveitis who do not respond to the therapy with steroids in the usual way may give more precision and shorten the establishment of diagnosis in this masquerade syndrome. Early diagnosis and therapy may improve the prognosis of NHL.

[Importance of pars plana vitrectomy in the diagnosis of ocular toxocariasis]. / Význam pars plana vitrektomie v diagnostice ocní toxokarózy.

A retrospective study evaluates the importance of pars plana vitrectomy (PPV) in four patients with ocular form of toxocarosis. The results of laboratory determination of the titres of antibodies against Toxocara canis (the ELISA method) in samples of vitreous body were compared with those in the serum of the patient. The individual cases exemplify the problems in interpretation of laboratory findings and document the authors' experience in considering the diagnosis of ocular toxocarosis in individual cases. The authors' experience indicates that PPV is of diagnostic as well as of therapeutic significance.

Hydrogen peroxide production by alveolar macrophages is increased and its concentration is elevated in the breath of rats exposed to hypoxia: relationship to lung lipid peroxidation.

Hypoxic exposure triggers a generation of reactive oxygen species that initiate free radical damage to the lung. Hydrogen peroxide is the product of alveolar macrophages detectable in the expired breath. We evaluated the significance of breath H(2)O(2) concentration for the assessment of lung damage after hypoxic exposure and during posthypoxic period. Adult male rats were exposed to normobaric hypoxia (10 % O(2)) for 3 hours or 5 days. Immediately after the hypoxic exposure and then after 7 days or 14 days of air breathing, H(2)O(2) was determined in the breath condensate and in isolated lung macrophages. Lipid peroxidation was measured in lung homogenates. Three-hour hypoxia did not cause immediate increase in the breath H(2)O(2); 5-day hypoxia increased breath H(2)O(2) level to 458 %. After 7 days of subsequent air breathing H2O2 was elevated in both groups exposed to hypoxia. Increased production of H(2)O(2) by macrophages was observed after 5 days of hypoxia and during the 7 days of subsequent air breathing. Lipid peroxidation increased in the periods of enhanced H(2)O(2) generation by macrophages. As the major increase (1040 %) in the breath H(2)O(2) concentration found 7 days after 3 hours of hypoxia was not accompanied by lipid peroxidation, it can be concluded that the breath H(2)O(2) is not a reliable indicator of lung oxidative damage.

[Endogenous mycotic endophthalmitis and pars plana vitrectomy (PPV)]. / Endogenní mykotická endoftalmitida a PPV.

PURPOSE: To report clinical findings, diagnostic and treatment possibilities of patients with endogenous fungal endophthalmitis (EFE). METHODS: Retrospective study of 13 patients (19 eyes) with EFE diagnosed and treated in the Dept. of Ophthalmology, 1st Medical Faculty, Charles University in Prague. A detailed personal medical history was taken in all patients. Standard ophthalmic examinations were performed in all cases. RESULTS: All of our patients had one or more of known risk factors for ocular fungal infections. There were intravenous drug users, immunosuppressed patients, postoperative patients receiving broad-spectrum antibiotics in our investigated group. The mean age of the patients was 39 years (from 19 to 68 years), the interval between the first ocular symptoms and correct diagnosis was up to 7 months (mean 2.1 months). Pars plana vitrectomy (PPV) was performed in 15 eyes and Amphotericin B was instilled into vitreous cavity at the end of the procedure. Amphotericin B was injected into vitreous without PPV in two eyes. All patients were treated with systemic antifungal agents. Only Candida albicans was the cause of EFE in 10 patients. Microscopic examination and culture were positive in 9 patients, 1 patient had positive serum antibodies against Candida albicans in significant titres. Final visual acuity improved in 47% of the eyes, stabilized in 36% of the eyes, and decreased in 17% of the eyes. CONCLUSION: Endogenous fungal endophthalmitis was seen as an opportunistic disease in all patients. Candida albicans was the only evidenced cause of fungal endophthalmitis. If prompt antifungal treatment after clinical suspicion of EFE begins, successful visual outcome is possible.

[Importance of diagnostic and therapeutic pars plana vitrectomy in endogenous uveitis]. / Význam diagnosticko-terapeutické pars plana vitrektomie u endogenní uveitidy.

OBJECTIVE: To evaluate the importance of diagnostic-therapeutic pars plana vitrectomy in patients with clinical manifestations of endogenous uveitis. PATIENTS AND METHODS: The diagnostic-therapeutic pars plana vitrectomy (DT PPV) has been performed at the Eye Clinic of General Faculty Hospital and 1st Medical Faculty on Prague on 62 eyes in 49 patients at the mean age of 45 years. The DT PPV was indicated in patients with uveitis of unusual clinical picture or poorly reacting to treatment, suspected infection or tumor etiology. In the beginning of PPV, 0.5 to 1.5 ml of undiluted vitreous body was samples and subsequently examined by microbiology, immunology and molecular genetic methods. PPV was performed on both eyes in 10 patients, on one eye twice in each of three patients. The authors evaluated 62 samples of vitreous body on the whole. The patients were observed for up to 96 months. RESULTS: Laboratory examination of the samples of vitreous body from 22 eyes (35.4%) supported our notion on infection etiology of intraocular inflammation, manifestations of intraocular tumor were in 12 eyes (19.3%), vascular or vitreoretinal pathology was present in 6 eyes (9.6%). Nonspecific inflammatory changes were detected in 22 eyes (35.4%). Drugs were administered into the vitreous body in 16 eyes. In the observation period the authors detected marked late complications in connection with DD PPV in 18 eyes (29%). Visual acuity improved by two or more lines of the Snellen optotypes in 43 eyes (69.3%), remained unchanged in 11 (17.7%) eyes. The vision deteriorated in 8 eyes (12.9%). CONCLUSION: Based on this experience the authors are of the opinion that DT PPV is indicated in patients with uveitis for giving more precision to the diagnosis of intraocular inflammation or a masking syndrome. DT PPV also represents a therapeutic procedure to cure complications connected with a severe form of inflammation and makes it possible to save central visual acuity.

The effects of hyperoxia, hypoxia, and ischemia/reperfusion on the activity of cytochrome oxidase from the rat retina.

Cytochrome oxidase activity from the retina can be enhanced or depressed by free radical-mediated reactions both in positive and negative aspect. The greatest effect was exerted by ischemia/reperfusion, which significantly increased the fluorescent products of lipid peroxidation (358 %, P < 0.01) and inhibited the enzyme activity (14%, P < 0.001). After hyperoxia the fluorescent products slightly increased (192%, P < 0.05) as well as the enzyme activity (133 %, P < 0.05). Hypoxia had no effect on any of these parameters. Specific changes in the composition of fluorophores after ischemia/reperfusion were revealed in the fluorescence spectra. The fact that increased lipid peroxidation after hyperoxia and after ischemia/reperfusion does not produce the same effect upon cytochrome oxidase activity might be explained by changes in the kinetic behavior of cytochrome oxidase. In the control enzyme preparation, two binding sites for cytochrome c were observed. One was of the low-affinity (Km = 60 microM) and the other of the high-affinity (Km = 1.12 microM). After in vitro-initiated lipid peroxidation, the low-affinity binding site was lost and the activity measured under "optimum" conditions at a single cytochrome concentration was higher than in the controls. This implies that oxidative damage to cytochrome oxidase in vivo can be site-specific and its extent should be estimated by performing detailed kinetic analysis as otherwise the results might be misleading.

[Role of nonenzymatic glycation and oxidative stress on the development of complicated diabetic cataracts]. / Uloha neenzymové glykace a oxidacního stresu v rozvoji komplikované diabetické katarakty.

Eye lens cataract can develop by various mechanisms the details of which are not completely known. Increased level of glucose in patients with diabetes mellitus represents one of the factors accelerating cataract development. As the lens does not depend on insulin, cataract formation is induced by hyperglycaemia both in IDDM and NIDDM patients. Glucose attacks free aminogroups of proteins and glycation products are formed by multistep non-enzymatic reactions. We can discriminate early and late products. The latter are often called as advanced glycation endproducts (AGE). They can accumulate inside the lens and interfere with its optical properties. With regard to the fact that glycation reactions are accompanied by autooxidation reactions, the overall process is usually referred to as glycoxidation. Free radical oxidations of membrane lipids give similar products as do glycation reactions, and there is synergy between these two pathways. Development of eye cataract is accompanied by a decrease in lens antioxidant capacity. A new class of glycation inhibitors has been observed recently. They are called Amadorins and they have therapeutic potential in the cataract treatment.

[The idiopathic uveal effusion syndrome]. / Syndrom idiopatické uveální efuze.

The authors describe two cases of idiopathic uveal effusion syndrome, in one instance affecting consecutively both eyes, in the second patient the finding is unilateral so far. In the female patient with the bilateral finding reattachment of the retina and improvement of the visual acuity developed only after surgery (sclerotomy). The second patient, where the disease was detected only accidentally, is so far only under observation. The authors discuss the causes of this rare disease, the variability of clinical symptoms, diagnostic and therapeutic possibilities.

Evaluation of the mutagenic effect of the new fungicide trimorphamide.

The new Czechoslovak fungicide trimorphamide was tested for its mutagenic activity. To evaluate the potential mutagenic effects on Drosophila, trimorphamide at 0.5, 1.0, 5.0, 10.0% was administered into the cultivation medium, and the sex-linked recessive lethal mutation detection test and the chromosome nondisjunction test were used. After administration of trimorphamide to mice at 60, 150 and 300 mg . kg-1 b.w. perorally, and 30, 70 and 150 mg . kg-1 b.w. intraperitoneally in single and repeated (5X) doses, a cytogenetic analysis of chromosomal aberrations in bone-marrow cells was performed. The cytogenetic analysis of human peripheral lymphocytes for chromosomal aberrations in vitro was performed 24 h after trimorphamide had been applied into the culture in concentrations 19.1 X 10(-3), 19.1 X 10(-4) and 19.1 X 10(-5) M. Under our testing conditions the trimorphamide concentrations used did not show any mutagenic effect upon Drosophila, compared with the controls. Also, under the conditions of the cytogenetic analysis, no significant increase in the frequency of chromosomal abnormalities in mouse bone marrow or in human peripheral lymphocyte was observed compared with the group of controls.

The mutagenic effect of the new insecticide and acaricide pyridathion.

The potential mutagenic effect of the new organophosphate insecticide and acaricide, pyridathion, was tested on Escherichia coli, strains WP2, WP2 uvrA, and on Salmonella typhimurium, strains TA100 and TA98, both with and without metabolic activation. The compound was tested at 1, 10 and 100 micrograms/ml. The analysis of chromosomal aberrations in mouse bone marrow was performed after a single peroral application of pyridathion at doses of 0.6, 1.11, 6.0, 12.0 and 24.0 mg . kg-1 b.w., i.p. application at 6.0 mg . kg-1 b.w., and repeated application (5 times) p.o. at 1.0, 2.5 and 5.0 mg . kg-1 b.w. Analysis of rat bone marrow was performed after a 3-month peroral application of pyridathion at 0.07, 0.175 and 0.35 mg . kg-1 b.w. An analysis of chromosomal aberrations in human peripheral lymphocytes in vitro was performed 24 h after the application of pyridathion into the culture in concentrations of 9.2 X 10(-3), 9.2 X 10(-4) and 9.2 X 10(-5) moles. The insecticide did not exert any mutagenic effect on the bacteria. There was no significant increase in the frequency of chromosomal abnormalities in bone marrow of mice of rats, or in human peripheral lymphocytes in vitro, compared with controls.