The degenerative and regenerative processes after the elimination of the proliferative peripheral retina of fish

We have analyzed the modifications in the tench (Tinca tinca) retina after the complete cryo-elimination of the proliferative growing zone (PGZ), which participates in the continuous growth of the retina throughout the life of the fish. By using immunohistochemistry and electron microscopy we demonstrated that, after the lesion, degenerative and regenerative processes take place in the PGZ, in the ciliary zone, and in the transition zone located between the PGZ and the central retina. After 120 days postlesion, the PGZ was completely regenerated and its composition was similar to that of the control animals. Numerous proliferative PCNA-positive cells reappeared and new ganglion cells were formed. In the transition zone and the central retina numerous proliferative PCNA-positive cells also appeared. These are arranged, on occasion, as columnar units from the inner to the outer nuclear layer where the rod precursors and the progenitor cells, respectively, were located. The Müller cells, closely associated with these columnar units, appeared to use them as guides to migration during the regenerative process. Notably, modifications occurred in the ciliary zone, whose cells acquired similar characteristics to the PGZ cells. The ciliary zone cells, the Müller cells, the rod precursors, and the proliferative cells located in the inner nuclear layer appear to participate actively in the regeneration of the PGZ.     

Pharmacodynamics of troxerutine in patients with chronic venous insufficiency: correlations with plasma drug levels

In a double-blind study the effects of troxerutine were assessed in patients with chronic venous insufficiency. The aim of this clinical pharmacological research was to evaluate, after a single oral dose: haemocoagulative and fibrinolytic balance, haemorheological changes and venous function. Correlation between such changes and simultanously assayed plasma drug levels was evaluated. The data obtained seems to give to troxerutine a more enlarged pharmacological characterization, especially regarding its demonstrated profibrinolytic and rheological activities. The maximal pharmacodynamic effects appeared simultaneous with the plasma drug peak.     

Analysis of bleomycin-induced mutagenic functions related to the PSO4 (= xs9) gene of Saccharomyces cerevisiae.

In the present work we analyse some properties of the pso4-1 (= xs9) mutant of the yeast Saccharomyces cerevisiae, which is blocked in both reverse mutation and recombination. We have applied the "apparent survival test" as a method to characterize putative inducible error-prone repair activities related to the PSO4 gene. As the mutagenic agent we have used bleomycin, which is an antitumour radiomimetic antibiotic. Survival, reverse mutation yield, and reverse mutation frequency were determined as a function of bleomycin concentrations (1-60 micrograms/ml) in the logarithmic phase of growth. It is shown that the PSO4 gene product is poorly involved in bleomycin sensitivity and that reverse mutation induced by this mutagen is dramatically reduced in the pso4-1 lys2 mutant strain, as compared with the isogenic SC7K (lys2) strain. M(x) functions exhibit linear-quadratic courses for both the SC7K (lys2) and the pso4-1 lys2 strains. The apparent survival functions display "humps" in both strains, corresponding to the resistant components of the survival functions. These facts suggest that the mutagenicity of bleomycin depends on at least one inducible error-prone repair pathway and that the PSO4 gene product could act as a mutation triggering factor.     

Evaluation of the detection of human papillomavirus genotypes in cervical specimens by hybrid capture as screening for precancerous lesions in HIV-positive women

Given the frequency and persistence of human papillomavirus (HPV) infection and associated cytological alterations in HIV-1-positive women, the incidence of uterine cervix neoplasm is likely to increase along with patient survival. More appropriate screening programs, which, in addition to Pap smears (PS), also include tests to detect and type HPV, are needed for the early identification of precancerous cervical lesions. This prospective study involved 168 HIV-positive (group A) and 100 HIV-negative women (group B). Cervicovaginal samples were collected for a PS and HPV DNA search. The detected virus was typed as high–intermediate oncogenic risk HPV (HR-HPV) and low-risk HPV (LR-HPV) using hybrid capture (HC) (Murex-Digene) and in-house PCR tests. The HC-detected prevalence of HPV was 111/168 (66%:HR 75.6%) in group A and 15/100 (15%:HR 42.9%) in group B (P < 0.0001). Polymerase chain reaction (PCR) was positive in 91% and 48%, respectively. No significant difference was observed between drug addicts and heterosexual HIV-1-positive women (P = 0.09). HPV was detected in 94% of the 57 HIV-positive women with cytological alterations. HR-HPV was found in 41/49 women with low-grade and 7/8 with high-grade squamous intraepithelial lesions (LSIL and HSIL, respectively). In women with a negative PS, HPV was detected in 57/111 cases (HR 63%) of group A and in 13/98 of group B (6 cases of HR). Of the 54 group A women who underwent biopsy, histology revealed that 41 had LSIL (18 with negative PS, 19 with LSIL, and 4 with HSIL; HR-HPV in 73% and LR-HPV in 17%), nine had HSIL (5 LSIL and 4 HSIL on cytology; HR-HPV in 89% and LR-HPV in 11%), and four were negative (all cytology negative; 3 HR-HPV and 1 LR-HPV). HR-HPV was more frequent as immunodepression worsened. These results show that cytological evaluation alone underestimated histological alterations in 23/50 women (42.6%), whereas the combination of Pap smear and HPV detection reduced this underestimate to 5%. J. Med. Virol. 56:133–137, 1998. © 1998 Wiley-Liss, Inc.     

Local advantage in the visual processing of hierarchical stimuli following manipulations of stimulus size and element numerosity in monkeys (Cebus apella)

Previous studies suggest that monkeys process local elements of hierarchical visual patterns more quickly and more accurately than they process the global shape. These results could be indicative of differences between relatively high visual functions of humans and non-human primates. It is, however, important to rule out that relatively low-level factors can explain these differences. We addressed this issue with two experiments carried out on capuchin monkeys (Cebus apella) using matching-to-sample tasks featuring hierarchical stimuli. The first experiment assessed whether manipulations of stimulus size can affect the local advantage so far observed in this New World monkey species. An overall local versus global advantage still emerges in capuchins, irrespectively of the amplitude of the visual angle subtended by the hierarchical shapes. Moreover, a local-to-global interference, indicative of a strong local advantage, was observed for the first time. In the second experiment, we manipulated size and numerosity of the local elements of hierarchical patterns, mimicking procedures that in human perception relegate the local elements to texture and enhance a global advantage. Our results show that in capuchin monkeys, a local advantage emerges clearly even when these procedures are used. These results are of interest since extensive neurophysiological research is carried out on non-human primate vision, often taking for granted a similarity of visual skills in human and non-human primates. These behavioural results show that this assumption is not always warranted and that more research is needed to clarify the differences in the processes involved in basic visual skills among primates.     

Bioavailability and toxicity of pentachlorophenol in contaminated soil evaluated on coelomocytes of Eisenia andrei (Annelida: Lumbricidae).

Pentachlorophenol (PCP) is widely distributed and highly persistent in soil, and represents a threat to the health of ecosystems. The present study aimed to assess the toxicity and bioavailability of PCP in soils as a function of different aging periods with the attempt to select a good toxicological assay for Eisenia andrei Bouché (Annelida: Lumbricidae). The experiments were performed on soil contaminated with PCP at 15 and 150ppm. After different aging periods (20, 60 and 120 days from spiking), bioavailability and toxicity were evaluated on E. andrei kept for 7 and 14 days in treated soils. The actual bioavailability decreased in relation to the aging for both PCP concentrations. No membrane damage was observed on coelomocytes collected by ethanol extrusion. Modifications in distribution of coelomocyte subpopulations were detected by flow cytometry on samples aged for 60 and 120 days at 150ppm PCP contamination. The reduction of lysosomal membrane stability, measured by neutral red retention time, was observed in all treatments. Worm mortality increased with aging in soils spiked with 150ppm of PCP. In conclusion, aging did not seem to reduce PCP cytotoxicity. This is the first report on in vivo toxicity of PCP evaluated on coelomocytes of E. andrei using different assays.     

A contiguous stretch of methionine residues mediates the energy-dependent internalization mechanism of a cell-penetrating peptide

Recently we characterized an unusual switch in the internalization mechanism of the monomeric and dimeric forms of the cell-penetrating peptide RDLWEMMMVSLACQY. Here, we observed both energy-dependent and energy-independent modes of peptide uptake by the target B-lymphocytes WI-L2-729HF2, suggesting that higher-order structure might modulate the action of this novel cell-penetrating peptide. In the present work, we propose a possible internalization mechanism for the dimeric peptide which involves an initial interaction with the cell membrane, followed by an energy-dependent internalization process which requires the contiguous Met(6-8) sequence.     

Renal angiomyolipoma and fever: assessment with isotopic renogram and 67Ga scintigraphy

A 26 year-old woman with tuberous sclerosis who came to the Emergency Department with high fever, bilious vomit, right hemiabdomen pain and syncope during 2 weeks. Laboratory analyses show hemoglobin 6.7 g/dl, creatinine 1.5 mg/dl and leukocytes 30,000. Abdominal CT is performed because of suspicion of active bleeding in right hemiabdomen, following rupture of right angiomyolipoma, treated by selective arterial embolization. She was referred to the Nuclear Medicine Department to perform a 67Gallium scintigraphy for the detection of infection, and static and dynamic renal scintigraphy for evaluation of the renal morphology and function.