Unusual behaviour of an immature loggerhead turtle released in the Alboran Sea

A juvenile loggerhead turtle with buoyancy problems was captured in the Alboran Sea (Mediterranean Sea, south of Spain) and released 14 months later after healing. Six days after the release, the turtle was seen swimming 42 km from the point of release, displaying unusual behaviour. We re-captured and released it again, 95 nautical miles offshore, near the Alboran Island. Ten days later the turtle arrived at the beach close to where it had been maintained in captivity. We discuss these findings in the context of behavioural alteration and habituation in released sea turtles. Capture-mark-recapture studies of sea turtles should be approached with caution as manipulated animals may modify their usual behaviour.

Haemodynamically unstable pulmonary embolism in the RIETE Registry: systolic blood pressure or shock index?

Patients with acute pulmonary embolism (PE) presenting with haemodynamic instability have the worst prognosis. However, what is understood by haemodynamic instability has not been clearly defined. The Registro Informatizado de la Enfermedad Tromboembólica (RIETE) is an ongoing registry of consecutive patients with symptomatic, objectively confirmed, acute deep vein thrombosis or PE. The present authors compared the predictive value of a systolic blood pressure (SBP) value of <100 mmHg and <90 mmHg and the shock index (cardiac frequency divided by SBP) on 30-day mortality in consecutive patients with PE. As of May 2006, 6,599 patients with PE were enrolled in the study. Of these, 417 (6.3%) died within 30 days: 153 of the initial PE, 29 of recurrent PE and 235 due to other causes. Of the 417 individuals who died, 127 (30%) had a positive shock index, 60 (14%) had SBP <100 mmHg and 33 (7.9%) had SBP <90 mmHg. On multivariate analysis any of the three parameters were independently associated with an increased mortality. The shock index had a higher sensitivity (30.5 versus 14.4 and 7.9% for SBP <100 mmHg and <90 mmHg, respectively) but lower specificity (86.3 versus 93.0 and 96.6). All three measures of haemodynamic instability are independent predictors of 30-day mortality. However, while the shock index had the highest sensitivity, a systolic blood pressure value <90 mmHg had the highest specificity.

Cadmium chloride-induced dysplastic changes in the ventral rat prostate: an immunohistochemical and quantitative study

BACKGROUND

Cadmium chloride is an environmental toxic that might be implicated in human prostate carcinogenesis. The study was directed: 1) to evaluate the immunoexpression of markers for cell proliferation, apoptosis, and resistance to apoptosis, and 2) to estimate the size of premalignant cell population in the preneoplastic changes induced in ventral prostates of rats treated with cadmium chloride administered in drinking water.

METHODS

The following parameters were calculated in the ventral prostatic lobe of normal rats and rats that received cadmium in drinking water during 18 months: total volume, epithelial volume, total number of epithelial cells, numerical density of epithelial cells, percentage of cells that immunostained to the proliferating cell nuclear antigen (PCNA), percentage of apoptotic cells (evaluated by a DNA fragmentation method), and absolute volume and volume fraction of immunostaining to bcl-2.

RESULTS

The percentage of PCNA immunoreactive nuclei, the bcl-2 expression, and the numerical density of epithelial cells were significantly (P < 0.05) increased in the dysplastic prostatic acini of treated rats in comparison with the normal acini of treated rats and control animals. The percentage of apoptotic nuclei from ventral dysplastic acini was significantly (P < 0.05) decreased in comparison with that of normal acini. A negative correlation between proliferation and apoptosis was found in dysplastic lesions.

CONCLUSIONS

Prostate epithelial dysplasia induced in rats by cadmium presents an increased proliferative activity and high expression of bcl-2 protein, as was described in human prostate intraepithelial neoplasia. However, the rate of apoptosis in rat dysplasia was importantly decreased, in contrast to that observed in some human preneoplastic changes. This decrease might be related to the increase of bcl-2 expression.

Immunohistochemical localization of protein gene product 9.5, ubiquitin, and neuropeptide Y immunoreactivities in epithelial and neuroendocrine cells from normal and hyperplastic human prostate

This study was designed to investigate (a) the presence of protein gene product 9.5 (PGP 9.5), ubiquitin, and neuropeptide Y (NPY) in the neuroendocrine and secretory epithelium of the human normal prostate and its secretions, and (b) the changes in immunoreactivity to these proteins in men with benign prostatic hyperplasia. Western blotting and light microscopic immunohistochemistry techniques were used and the numerical density of immunoreactive neuroendocrine cells, and the volume fractions of immunostained secretory epithelium were evaluated. Western blotting revealed the presence of the three antigens in both tissue homogenates and prostate secretion. Some neuroendocrine cells immunoreacted to PGP 9.5 and NPY in all the prostate regions of control specimens. Ubiquitin immunoreactivity was detected in the nuclei from both basal cells and secretory epithelial cells. The cytoplasm of the secretory cells and the glandular lumen also showed immunostaining for the three proteins. The numerical densities of both PGP 9.5 and NPY neuroendocrine cells were lower in hyperplasia than in controls. No differences in the volume fraction occupied by epithelial immunostaining to both proteins was found between hyperplastic and control prostates. We concluded that (a) PGP 9.5 and NPY, but not ubiquitin, are common antigens in both neuroendocrine and secretory prostate cells, (b) the three immunoreactive proteins contribute to the prostate secretions, and (c) the secretion of ubiquitin is markedly diminished in the hyperplastic epithelium.(J Histochem Cytochem 48:1121-1130, 2000)

[Susac syndrome: clinical and diagnostic approach. A new case report]

INTRODUCTION

The Susac syndrome is made up of the clinical triad: encephalopathy, visual and hearing defects. It is caused by microangiopathy of unknown origin affecting the small arteries of the brain, retina and cochlea. It is very uncommon. It mainly affects young women. The course of the illness is usually monophasic and self-limiting. The deficit of visual acuity is caused by occlusion of tributaries of the retinal artery. The auditory defect is bilateral and symmetrical, and particularly affects medium and low frequencies. NMR is of great diagnostic value, showing multiple lesions in the grey and white matter. Our case gives more data regarding the evolution of this condition and the contribution of cerebral SPECT to diagnosis, the results of systemic treatment, use of hyperbaric oxygen and reflections on the physiopathology of the process.

CLINICAL CASE

We present the clinical case of a young woman who presented with psychiatric symptoms and migraine followed by clinical encephalopathy and acute/subacute coma. There were also visual and auditory deficits. Other types of systemic disease were ruled out.

CONCLUSIONS

Findings on SPECT suggested the presence of a microangiopathic disorder of the brain. The patient responded to systemic treatment with cortico-steroids. The encephalopathy resolved in a few days and two months later she had resumed her former daily activities. Treatment with hyperbaric oxygen definitely reduced visual sequelae.

Changes in the number, proliferation rates, and bcl-2 protein immunoexpression of epithelial and periductal cells from rat epididymis during postnatal development

To investigate 1) the correlation between the proliferative activity of epididymal epithelium plus myoid cells and the increase in the number of these cells and 2) the role of the basal epithelial cells in the renewal of epididymal epithelium, a quantitative evaluation of the proliferation of both epithelial cells and periductal myoid cells in the different epididymal regions (caput, corpus, and cauda) has been carried out during postnatal development of the rat by immunohistochemical evaluation of BrdU-labeling indices. These data were correlated with cell numbers and counted by the optical dissector method. The presence of bcl-2 protein was immunohistochemically detected and evaluated. No significant differences in BrdU indices were observed among epididymal regions in any stage studied. Cell proliferation decreased from the prepubertal period to adulthood in both epithelial and myoid cells in the three regions of the epididymis, suggesting a close relationship between epithelial and mesenchymal components. The numbers of both cell types were significantly higher in the caput than in the corpus and cauda in all stages studied, suggesting functional differences between regions. A negative linear correlation between proliferative activity and cell numbers was noted that might be related to regulation of the cell population size. Basal cells showed a lower proliferation rate than principal cells, but most of the immunoreactive bcl-2 protein, in pubertal and adult epididymides, was observed in basal cells. Therefore, these cells might comprise a low-proliferating and apoptosis-resistant population.

Sordarin inhibits fungal protein synthesis by blocking translocation differently to fusidic acid

Sordarin derivatives are selective inhibitors of fungal protein synthesis, which specifically impair elongation factor 2 (EF-2) function. We have studied the effect of sordarin on the ribosome-dependent GTPase activity of EF-2 from Candida albicans in the absence of any other component of the translation system. The effect of sordarin turned out to be dependent both on the ratio of ribosomes to EF-2 and on the nature of the ribosomes. When the amount of EF-2 exceeded that of ribosomes sordarin inhibited the GTPase activity following an inverted bell-shaped dose-response curve, whereas when EF-2 and ribosomes were in equimolar concentrations sordarin yielded a typical sigmoidal dose-dependent inhibition. However, when ricin-treated ribosomes were used, sordarin stimulated the hydrolysis of GTP. These results were compared with those obtained with fusidic acid, showing that both drugs act in a different manner. All these data are consistent with sordarin blocking the elongation cycle at the initial steps of translocation, prior to GTP hydrolysis. In agreement with this conclusion, sordarin prevented the formation of peptidyl-[(3)H]puromycin on polysomes from Candida albicans.

Inflammatory pathogenesis of cortical polymicrogyria: an autopsy study

Polymicrogyria, a cortical abnormality usually classified among neuron migration disorders, is characterized by different etiologies and pathogeneses. Recently, it has been proposed that polymicrogyria could be acquired as a consequence of a lasting damage to the developing brain. In this study, we test the hypothesis that an infection in the fetal adnexa may give rise to distant brain defects and eventually polymicrogyria. Thirty-two fetuses spontaneously aborted for extensive ascending chorioamnionitis at 15-26 wk of gestation were evaluated. Control subjects were represented by 8 fetuses aborted at 15-24 wk of gestation. A complete autopsy was carried out between 4 and 12 h after fetal expulsion. We found different histologic alterations in the primitive cortical architecture, both isolated and combined (undulation of the cortical ribbon, untimely cortical folding/molecular layer fusion, and neuronal loss). A total of 25 cases presented one or more of the above-described morphologic alterations in the brain (78%). On the contrary, similar alterations were never observed in any of the control brains (p=0.019). Our findings indicate that chorioamnionitis significantly impairs brain cortex morphogenesis. Such neuron damage may be caused by an unspecific, indirect mechanism of injury to the developing cortex involving hypoxia and free radical generation. The reported brain abnormalities may even evolve into polymicrogyria in surviving fetuses.

Sordarins: A new class of antifungals with selective inhibition of the protein synthesis elongation cycle in yeasts

GR135402, a sordarin derivative, was isolated in an antifungal screening program. GR135402, sordarin, and derivatives of both compounds were evaluated for their ability to inhibit cell-free translational systems from five different pathogenic fungi (Candida albicans, Candida glabrata, Candida krusei, Candida parapsilosis, and Cryptococcus neoformans). The activity profile of GR135402 is extended to other chemical compounds derived from sordarin. Experimental results indicate that sordarin analogs exert their antifungal effects by specifically inhibiting the protein synthesis elongation cycle in yeasts but do not affect protein synthesis machinery in mammalian systems. Intrinsically resistant strains owe their resistance to differences in the molecular target of sordarins in these strains. Preliminary studies performed to elucidate the mode of action of this new class of antifungal agents have shown that the putative target of sordarins is one of the protein synthesis elongation factors.

Identification of elongation factor 2 as the essential protein targeted by sordarins in Candida albicans

The target for sordarins in Candida albicans has been elucidated. Kinetic experiments of sordarin inhibition as well as displacement experiments showed that the formation of a sordarin-target complex follows a reversible mechanism. Binding of tritiated drug to the target is enhanced in the presence of ribosomes. Isolation of the target by classical protein purification methods has allowed us to identify it as elongation factor 2. This is in agreement with the nature of sordarin derivatives as specific inhibitors of the elongation cycle within protein synthesis in yeasts.

[Concomitant hyperfractionation of drugs and irradiation in the treatment of advanced ENT cancers]

Considering the limited results achieved up to now in the treatment of advanced ENT-cancer, with the classic customary procedures, the AA. suggest a new therapeutic schedule (within the concurrent radio-chemotherapy context) in which the selected cytotoxic drug, the carboplatin, is a part of each therapeutic fraction. A group of 36 patients suffering advanced ENT-cancer (2 cases stage III and 34 stage IV) were studied between Mars 1993 and September 1995, and the outcomes assessed after a 18 months mean follow-up (30 months maximum). There were 11% surgically rescued cases, being the full dosage administered twice daily 8.050 cGy plus 700 mg carboplatin. Tolerance was very good, so 100% of the patients received a complete treatment. Initial response was also fine resulting 93% full remissions on primaries, 96% on neck adenopathies (6% surgical rescues). Regarding the actuarial control after 30 months were controlled 88% of neck adenopathies, control loco-regional amounted for 69%, control on primaries 63% and actuarial survival amounted 55%. The AA. drawn out 10 conclusions, underlining the good tolerance of the therapeutic sketch proposed, because the antineoplastic results are by far better than those experienced with whichever modality of management of tumors of these sites and staging.

Essential residues in lysolecithin:lysolecithin acyltransferase from rabbit lung: assessment by chemical modification

The inhibition of lysolecithin:lysolecithin acyltransferase by several specific reagents was studied. Diisopropyl fluorophosphate (DFP) completely inhibited both activities at a concentration of 4 mM. Activity was not protected by substrate and the enzyme showed a change in circular dichroism spectrum upon treatment with inhibitor. Phenylmethanesulfonyl fluoride, another serine-specific reagent, did not inhibit either hydrolysis or transacylation. Therefore, we suggest that DFP does not modify an active serine in the catalytic site. p-Hydroxymercury benzoate and N-ethylmaleimide (NEM) abolished both activities of the enzyme. The presence of substrate partially protected against inactivation. Far-uv CD spectrum of NEM-modified enzyme revealed no changes in protein structure. The existence of two classes of essential cysteine residues was deduced from kinetics of NEM inactivation. Both classes differ in NEM reactivity and also in their participation in the catalytic mechanism. A tyrosine-specific reagent, tetranitromethane, also inhibited hydrolysis and transacylation, following first-order kinetics. The partial protection by substrate suggested the possible existence of essential tyrosines near the active site. At pH 5.0 N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline inactivated hydrolysis but not transacylation. However, both of them remained unchanged at pH 6.5. The substrate prevented the loss of hydrolytic ability. Therefore, a carboxyl residue participating just in the catalytic mechanism of hydrolysis is proposed.

Evidence of a pH-dependent conformational change at the active site of lysolecithin:lysolecithin acyltransferase from rabbit lung

It has been shown that both activities, hydrolysis and transacylation, of lysolecithin:lysolecithin acyltransferase, as well as the conformation of the polypeptide are critically dependent on a pK around 5.8, but the question remains if the same residue(s) is responsible for the conformational change and the loss of activity. In this paper, ultrasonic cavitation is used to study the pH-dependent inactivation. The results show that there are two first-order inactivation constants which depend on pH and that the transition between them has a pK of 5.9. As the constants of ultrasonic inactivation are very dependent on the accessibility of the residues it is concluded that the conformational change modifies the accessibility of the active site.