Polystyrene as an inert medium in the synthesis of the styrene/divinylbenzene/acrylonitrile copolymers

Samples of styrene/divinylbenzene/acrylonitrile macroporous copolymers were prepared, using polystyrene as inert medium. The initial viscosity average molecular weight of the polystyrene samples were: M?_v.i=87000, 98000, 117000 and 218000. The polystyrene samples with the initial molecular weights M?_v.i=87000 and M?_v.i=117000 were reused as inert media, for many times, until they lost their capacity to produce permanent porosity of the copolymers. The macroporous copolymers were characterized by their permanent porosity and volume swelling. If a polystyrene sample is used for many times, the molecular weight of the polystyrene removed (extracted) is gradually diminished and therefore the permanent porosity of the macroporous copolymers decreases step by step. The reasons responsible for this behaviour are:

• during the copolymerization process a polystyrene with a smaller molecular weight is formed.
• polystyrene parts of high molecular weights are included in the network structure of the macroporous copolymers.

The evidence for this was given by plotting the differential and integral molecular weight distribution curves for six samples of polystyrene.     

Comparison of structural genetics of non-schistosoma-associated squamous cell carcinoma of the urinary bladder

Little is known about genetic changes in squamous differentiation of non-schistosomiasis-associated bladder cancer. Therefore, we investigated pure squamous cell carcinomas (SqCC), squamous parts of mixed urothelial carcinomas with squamous differentiation (MIX) and mere urothelial cancers (UC) for structural genetic differences. Tissue microarray slides (n = 29 SqCC, n = 35 MIX and n = 23 UC) were analyzed by ZytoLight SPEC p16/CEN3/7/17 Quadruple Color Probe fluorescence-in-situ-hybridization (FISH) and DNA was investigated by comparative genomic hybridization (CGH) (n = 35 SqCCs, n = 40 MIX and n = 36 UC). By FISH the mean number of polysomic cells was lowest in SqCC (CEN3 P = 0.0498, CEN17 P = 0.0009). A slight tendency of lower copy numbers of chromosomes 3, 7 and 17 and higher numbers of the p16-locus in SqCC (P = 0.45) indicated less aneuploid tumor cells in SqCC compared to MIX and UC. In CGH SqCC showed the lowest mean number of aberrations per tumor (SqCC 5.37 changes, MIX 6.75 and UC 7.64; P = 0.1754). Significant differences between the three groups were found for loss of chromosome 3p (P = 0.004), 6q (P = 0.028), 11p (P = 0.024) and gains of 5p (P = 0.020). Loss of 3p was more frequent in SqCC (51.4%) than in MIX (37.5%) or UC (13.9%). To conclude, SqCCs show less polysomy and genetic alterations than MIX and UC. Loss of 3p is more frequent in SqCC but there are no absolute specific alterations for each tumor group. Squamous parts of mixed tumors show similar alterations than UC and should be considered as further development of UC, while pure SqCC seem to be a separate tumor group.     

Reproducibility and agreement between three methods of intraocular pressure measurement

OBJECTIVE: The aim of the present study was to establish reproducibility between consecutive intraocular pressure measurements using the same method of tonometry as well as to assess agreement between 3 different methods of tonometry. MATERIALS AND METHODS: The study included 55 patients. Intraocular pressure of 94 eyes was measured, using Goldman applanation tonometry, Maklakoff applanation tonometry and indentation tonometry according to Schioetz method. The mean values and the differences in intraocular pressure measurements were calculated (using Bland and Altman method) in order to assess agreement between Goldman and Maklakoff applanation tonometry and Goldman and Schioetz tonometry. Reproducibility of the methods was assessed based on three consecutive intraocular pressure measurements on three groups of 20 eyes at 5-minute intervals. RESULTS: The mean intraocular pressure (Po) measured by Goldman method was 23.26 +/- 0.78 mmHg, the mean pressure estimates (Po) according to Maklakoff method were 19.4 +/- 0.64 mmHg and it (Po) was 21.18 +/- 0.74 mmHg using Schioetz tonometry. The correlation (Pearson) between Goldman Po and Maklakoff Po was 0.74 and between Goldman and Schioetz Po - 0.93. Mean differences were 4.12 +/- 0.53 and 2.08 +/- 0.3 mmHg respectively. Variation coefficients between consecutive measurements were: for Goldman tonometry - 2.00%, for Maklakoff - 7.90% and for Schioetz - 5.72%. CONCLUSIONS: According to Bland and Altman method there is low agreement between intraocular pressure estimates obtained by Goldman and Maklakoff tonometry, i.e. these methods are not interchangeable. This fact might be explained by the high variation coefficient of Maklakoff method. The low variation coefficient of Goldman tonometry makes it the most accurate of the three methods.     

Prevalence and Location of Obstetric Lacerations in Adolescent Mothers

Study Objective

The objective of this study was to describe prevalence and location of obstetric lacerations in adolescents.

Neovascular glaucoma

Neovascular glaucoma is a severe eye disorder classified as a secondary glaucoma and the most common of this type of disease. It is caused by a number of ocular and systemic conditions, which share the common element of retinal ischemia/hypoxia that initiates the subsequent release of angiogenesis factors. The most common causes of neovascular glaucoma are diabetic retinopathy and the occlusion of central retinal vein, of carotid artery, and of central retinal artery. More rarely, neovascular glaucoma can be secondary to eye tumors, traumas and uveitis. The present article reviews the stages of angiogenesis, forms of neovascularization and the clinical stages of the disease. Differential diagnosis is made and modern treatment of neovascular glaucoma is reviewed: treatment of iris neovascularisation, of extensive neovascular glaucoma and of end-stage neovascular glaucoma. Being a disease with poor prognosis, neovascular glaucoma should be well known not only by ophthalmologists but also by general practitioners, endocrinologists, neurologists, rheumatologist, and cardiologists. Only a timely diagnosis and adequate treatment can assure patients that they will preserve their vision and/or eye for a longer time.     

Mitochondrially targeted vitamin E and vitamin E mitigate ethanol-mediated effects on cerebellar granule cell antioxidant defense systems

Ethanol (EtOH) disrupts the structure and function of the developing nervous system, sometimes leading to birth defects associated with fetal alcohol syndrome (FAS). Animal FAS models indicate that cellular membrane peroxidation, intracellular oxidant accumulation, and suppression of endogenous antioxidant enzymes contribute to the toxic effects of EtOH. Mitochondrially targeted vitamin E (MitoVit E), a chemically engineered form of vitamin E (VE) designed to accumulate in the mitochondria, has been shown to inhibit intracellular oxidant accumulation and cell death more effectively than VE. In previous investigations, we have shown that, in vivo, VE reduces neuronal death in the developing cerebellum of EtOH-exposed animals, and, in vitro, VE prevents apoptotic and necrotic death of EtOH-exposed cerebellar granule cells (CGCs). The present investigation shows that, in a FAS CGC model, 1 nM MitoVit E renders significant neuroprotection against EtOH concentrations as high as 1600 mg/dL. The present study also demonstrates that, in this same model, MitoVit E mitigates EtOH-induced accumulation of intracellular oxidants and counteracts suppression of glutathione peroxidase/glutathione reductase (GSH-Px/GSSG-R) functions, protein expression of gamma-glutamylcysteine synthetase (gamma-GCS), and total cellular glutathione (GSH) levels. In the presence and absence of EtOH, VE amplifies the protein expression levels of gamma-GCS, an enzyme that performs the rate-limiting step for GSH synthesis, and total GSH levels. These results suggest that MitoVit E and VE ameliorate EtOH toxicity through non-oxidant mechanisms-modulations of endogenous cellular proteins-and antioxidant means.     

Comparison of the ImmunoCyt test and urinary cytology with other urine tests in the detection and surveillance of bladder cancer

Despite several new urine markers urinary cytology remains the gold standard for the non-invasive detection of bladder carcinoma. The use of monoclonal antibodies against tumor associated antigens offers a promising approach to improve urinary cytology. The aim of this study was to compare fluorescence immunocytology (ImmunoCyt/Ucyt+ test), alone and in combination with the conventional cytology, with other urine markers. Urine samples from 126 patients undergoing cystoscopy were included in the study. Among them, 42 patients had urothelial carcinoma, two dysplasia, two other malignancies, and 78 had no evidence of bladder cancer. Urine samples were taken before any manipulation. We used the ImmunoCyt test and Papanicolaou staining for conventional cytology. The ImmunoCyt slides were examined under a fluorescence microscope. Evaluations of the tests were blinded to clinical and pathological data and were carried out by three independent observers. The results of cytology and ImmunoCyt were compared with the BTAstat, NMP22, Lewis X, 486p3/12, and Urovision tests. The sensitivity for the ImmunoCyt test was 78.3% and for conventional cytology 84.6%. The combination of ImmunoCyt and cytology showed a sensitivity of 89.1%. The specificity was 73.8% for the ImmunoCyt alone, 80.0% for the cytology, and 72.5% for the combination of ImmunoCyt and cytology. Sensitivities for the other tests were 68.8% for (FISH), 66.6% (BTA-Stat), 68.8% (486p3/12), 95.5% (Lewis X), and 71.1% for (NMP22). Specificity was 89.1% for (FISH), 78.2% (BTA-Stat), 76.4% (486p3/12), 32.8% (Lewis X), and 65.5% for (NMP22). Urinary cytology can be improved by immunostaining with monoclonal antibodies against tumor-associated antibodies. The combination of ImmunoCyt with conventional cytology offers a superior sensitivity to other commercial tests. The ImmunoCyt test provides a useful supplement to urinary cytology in the diagnosis of bladder cancer.M.I. Toma, M.G. Friedrich contributed equally to this study     

Ethanol-induced reduction of neurotrophin secretion in neonatal rat cerebellar granule cells is mitigated by vitamin E

Ethanol exposure during nervous system development produces a range of abnormalities, and in humans may lead to the fetal alcohol syndrome. Among the mechanisms hypothesized to play roles in ethanol neurotoxicity are altered expression of supportive neurotrophic factors (NTFs), and cellular disturbances in oxidative processes. In this study, ethanol effects on secretion of two NTFs, brain-derived neurotrophic factor, and neurotrophin-3 were analyzed in neonatal rat cerebellar granule cells, and the potential of the antioxidant vitamin E to modulate ethanol effects was investigated. Ethanol exposure in these preparations reduced NTF secretion, but vitamin E appreciably ameliorated the ethanol effects. Possible mechanisms underlying both the ethanol effects on NTF secretion, and the protection of this antioxidant are considered.     

Preparation and characterisation of poly(vinyl alcohol)/cyclodextrin microspheres as matrix for inclusion and separation of drugs

Poly(vinyl alcohol) (PVA) microspheres containing cyclodextrin (CD) were obtained by chemical cross-linking with glutaraldehyde of an acidified mixture solution of PVA and alpha-, beta- or gamma-CD. The amount of linked CD in microspheres, estimated by tetrazolium blue method, decreases in the order beta- > gamma- > alpha-CD. The dimensions of PVA/gamma-CD microspheres are much higher than those of PVA/alpha- and beta-CD. The cross-linking density of microspheres was estimated by the amount of iodine retained by the polymer matrix. The pore size as well as the porous volume of PVA/CD microspheres decrease significantly on increasing the amount of glutaraldehyde, but are enough large to permit the access of drugs to the CD cavity. In order to test the PVA/CD microsphere inclusion ability, the microspheres were packed in a glass column and the liquid chromatographic behaviour by isocratic elution of different drugs or typical organic compounds, taken as model drugs, was investigated.     

Are false-positive urine markers for the detection of bladder carcinoma really wrong or do they predict tumor recurrence?

INTRODUCTION AND OBJECTIVES: A problem in the interpretation of noninvasive urine tests for detection of bladder carcinoma is the finding of false-positive results. Several authors have described that patients with false-positive results are at high risk for tumor recurrence or progression. Only few data are available for comparing the clinical course of patients with false-positive test results and patients with true-negative results. We studied whether patients with false-positive results of various urine test had a higher recurrence rate than patients with true-negative results. METHODS: Urine samples from 61 patients without evidence of active bladder carcinoma were included. Of the 61 patients, 51 had a history of bladder cancer, and 10 underwent transurethral resection for suspect of bladder carcinoma but had negative pathologic findings. Immunocytology (Lewis X and 486p3/12) was performed on bladder washings, and BTAstat and NMP22 were performed on urine samples. RESULTS: During the follow-up period, 22 patients had one or more false-positive BTAstat test results, 25 patients had one or more false-positive NMP22 tests, 42 patients had at least one false-positive Lewis X test, and 11 patients had one or more false-positive 486p3/12 test. During a follow-up period of 3-39 months (median, 17.6 months) four patients expected a tumor recurrence. Among patients with false-positive urine test results 2 of 22 (9.1%, BTAstat), 2 of 25 (8%, NMP22), 4 of 42 (9.5%, Lewis X), and 3 of 11 (27.2%, 486p3/12) suffered from tumor recurrence. In contrast, among patients with true-negative test results 2 of 39 (5.2%, BTAstat), 2 of 36 (5.6%, NMP22), 0 of 18 (0%, Lewis X), 1 of 50 (2.0%, 486p3/12) had a tumor recurrence. CONCLUSIONS: Patients with a false-positive urine test result do not generally have a greater risk of tumor recurrence or progression than patients with a true-negative result. In our series, only patients with false-positive 486p3/12 test result had a higher recurrence rate. Our findings do not justify a more aggressive adjuvant treatment or surveillance for patients with false-positive urine tests.