Elemental levels in tree-bark and epiphytic-lichen transplants at a mixed environment in mainland Portugal, and comparisons with an in situ lichen.

Samples of Platanus hybrida Brot. bark and Flavoparmelia caperata (L.) Hale thalli, from a clean area in northern Portugal (Baião), were transplanted into an exposure location at the south-western Atlantic coast, impacted by urban-industrial emissions (Sines), for a 10-month long experiment. Bark pieces were confined into nylon bags (2-mm mesh), and lichen thalli kept with their bark substrate (Pinus pinaster (Ait.) Sol.). Every two months, a double set of transplants (one for bark, one for lichens) was brought back into the laboratory, together with native samples of Evernia prunastri (L.) Ach. Following suitable cleansing and preparation procedures, field samples were put through INAA for elemental assessment. The results indicate that, regardless of signal magnitude, (1) concentrations in bark and lichen transplants are significantly correlated with atmospheric deposition for an appreciable number of elements; (2) there are a number of significant correlations between transplanted and native samples, and again between the latter and the deposition; and (3) the elements with biological patterns that follow the deposition in either transplanted or native samples (Co, V) are the very ones whose bioaccumulation seems to benefit from an alternation of wet-dry periods, which fits the precipitation record of the test site during the exposure term.

Octreotide in acute bleeding esophageal varices: a prospective randomized study.

BACKGROUND/AIMS: To assess the value of octreotide in the control of acute bleeding esophageal varices, in a prospective randomized study. METHODOLOGY: One hundred and ninety-seven patients admitted for variceal bleeding confirmed at endoscopy were recruited and divided into two groups: group I (n = 111) with endoscopic stigmata of recent bleeding; and group II (n = 86) with active bleeding at emergency endoscopy. Patients in group I were randomized to receive a continuous infusion of octreotide (n = 58) or emergency sclerotherapy (n = 53). Patients in group II were assigned to sclerotherapy (n = 42) or to sclerotherapy plus octreotide (n = 44). At the end of the period of study (48 hours), patients were submitted to sclerotherapy or band ligation until variceal obliteration was achieved. RESULTS: In group I, octreotide was found to be as effective as sclerotherapy regarding hemostasis at 48 hours and on day 7 after the index bleeding episode. Transfusion needs were not significantly different for the two treatment modalities. In group II, the association of octreotide with sclerotherapy was significantly better than sclerotherapy alone either in controlling acute active bleeding (P < 0.001) or in achieving hemostasis at 48 hours (P < 0.01). Transfusion needs were significantly fewer in patients treated with this therapeutic association as compared to sclerotherapy alone. CONCLUSIONS: These results suggest that octreotide infusion is effective in the treatment of variceal bleeding. In patients with recent bleeding, octreotide infusion is as effective as emergency sclerotherapy. In active variceal bleeding, it is a valuable adjuvant treatment in association with emergency sclerotherapy.

Oesophageal lichen planus.

Lichen planus is a common skin and mucosal disease, with very rare symptomatic oesophageal involvement. We report a case of painful dysphagia due to oesophageal lichen planus in a 60-year-old woman who also had oral, cutaneous and genital lichen planus lesions. Steroid treatment produced considerable improvement of all lesions and a rapid symptomatic remission.

Endoscopic Nd-YAG laser therapy as palliative treatment for esophageal and cardial cancer.

BACKGROUND/AIM: Progressive dysphagia is the most important symptom in inoperable cases of carcinoma of the esophagus and cardia. Treatment for the relief of dysphagia is chosen based on the lowest mortality and morbidity. This paper describes alpha consecutive series of patients with esophageal or cardial cancer, without a documented tracheoesophageal fistula, who were referred for palliative laser therapy. Alternative palliative treatments are discussed, as well as factors involved in successful laser treatment. MATERIAL AND METHODS: Over a five year period, 104 patients were treated endoscopically with the Nd-YAG laser for symptomatic improvement dysphagia caused by malignant tumors of the esophagus or cardia. RESULTS: After the initial laser therapy, good improvement was achieved in 78 patients (75%) and fair improvement in 17 patients (16%). Eighty-three patients with significant improvement were followed until death. In 42 of these 83 patients, the initial laser therapy was the only treatment given; the remaining 41 patients required either additional laser treatment or other palliative therapy. CONCLUSION: Laser treatment for palliation in esophageal and cardial cancer is promising. Given the proper circumstances, it may lay the framework for many other important treatment modalities.

Viability and respiratory activity of Pseudomonas syringae cells starved in buffer.

Pseudomonas syringae cells starved in buffer released orcinol-reactive molecules and materials that absorbed ultraviolet light. The number of cells culturable in nutrient medium decreased more rapidly than the number of intact particles determined by microscopy. The results suggested that starvation resulted in the lysis of an increasing number of cells, and that a fraction of the intact particles were not culturable. Starvation also resulted in a decrease in the rate of oxygen consumption with acetate, glycerol, and succinate, but at different levels. Whereas the respiration of acetate and glycerol decreased concomitantly with culturability, the respiration of succinate decreased to levels similar to the concentration of intact cells, suggesting that all intact particles respired the succinate, but only the culturable cells respired the acetate and glycerol. The results suggest that measuring the activity of the electron-transport system can overestimate the viability of starved bacterial cells, and that complex metabolic activities such as the respiration of acetate and glycerol are probably better suited for the evaluation of this parameter.

S-100 protein and glial fibrillary acidic protein (GFAP) in experimentally induced and spontaneous tumours of peripheral nerves in BDVI rats. Light microscopic and immunohistochemical study.

Twenty-five ethylnitrosourea (ENU) induced and 24 spontaneous tumours of peripheral nerves as well as 28 spontaneous mesenchymal tumours in BDVI rats were studied by light microscopy and immunohistochemically for the presence of S-100 protein (S-100). Early ENU-induced schwannomas*) representing the thickenings of nerves showed weak or negative S-100 immunoreactivity. S-100 positivity (both in the cytoplasm and nucleus) was observed in all large ENU-induced tumours found in animals dying or killed at advanced age. Immunostaining was present in both cystic and solid areas of schwannomas. S-100 positivity was found in 20 of 24 spontaneous schwannomas: 14 of 20 positive tumours contained cysts. Twenty-seven schwannomas (12 ENU-induced and 15 spontaneous) were studied for the presence of glial fibrillar acid protein (GFAP) and 13 were positive (7 had cystic areas). GFAP-positivity was relatively high in 4 tumours (3 ENU-induced and 1 spontaneous); these tumours also showed intense S-100 reactivity. Immunoreactivity for S-100 occurred more frequently and was much more intense than that for GFAP. The incidence of spontaneous peripheral nerve tumours in BDVI males reached 4%, cystic schwannomas being the most frequent type. All spontaneous mesenchymal tumours except lipoma (S-100 positive) were negative for S-100 protein and for GFAP.

The use of analysis of covariance to assess repeatability in electrode performance.

The repeatability of a K(+)-selective glass electrode and a Cu(2+)-selective solid-state electrode was assessed by the determination of the variation of the slope and potentials in successive calibrations, and by analysis of covariance of the regression lines of potential vs. logarithm of ion activity. When assessed by any one of these three methods, both electrodes displayed high repeatability in most of the calibration sets. However, in several calibrations, the variation of the slope and potential was low, but the regression lines were statistically different. In no case was the variation of the slope and potential high and the regressions not statistically different. The results suggested that analysis of covariance can be used to test electrode repeatability, and provides a more restricted evaluation of this parameter than the variation of the slope and potential. The characteristics of analysis of covariance suggest that it provides an objective and rigorous test for electrode repeatability. The advantages of the use of analysis of covariance over the determination of the variation of the slope and potential are listed.

A simple program in BASIC to compare regression lines by analysis of covariance.

Most of the biological processes can be described by linear relationships. The comparison of regression lines is therefore very common in biological research. This paper presents a program written in BASIC that compares the slopes, intercepts and lines of regressions, using analysis of covariance.

Dodecylguanidine monoacetate (dodine) causes severe membrane damage in Pseudomonas syringae above the critical micelle concentration.

The release of K+ from Pseudomonas syringae cells treated with dodecylguanidine monoacetate (dodine) was followed with a K(+)-selective glass electrode. Treatment of the cells with 5-15 mumol/l dodine resulted in low levels of K+ release, but higher surfactant concentrations caused extensive and rapid K+ efflux. Dodine concentrations that caused high K+ release also induced significant leakage of inorganic phosphate. The addition of 5-10 mumol/l dodine also caused an increase in the rate of oxygen consumption in the presence of glycerol or succinate, but an increase in concentration from 10 to 40 mumol/l resulted in a concomitant decrease in O2 consumption. The results from this and previous work suggest that dodine inhibits respiration firstly by causing drainage of coenzymes, and then by a direct interaction with the components of the respiratory chain. Previous work showed that above 25 mumol/l, dodine molecules aggregate to form micelles. The results therefore suggests that, in contrast with other cationic amphiphiles, the micellar form of dodine is more damaging to the cytoplasmic membrane than the free molecules.

Mode of antibacterial action of dodine (dodecylguanidine monoacetate) in Pseudomonas syringae.

Treatment of Pseudomonas syringae cells with 50 microM dodecylguanidine monoacetate (dodine) resulted in the rapid degradation and release of RNA and cell lysis. Higher concentrations resulted in a progressive decrease in the intensity of these responses, and the appearance of extensive zones of coagulated cytoplasm, indicating that the decrease in RNA degradation probably resulted from an inhibition of the RNases, due to protein denaturation. Dodine also induced expansion of the outer membrane, with the formation of protuberances and intracellular myelin-like structures, which were already evident after 1 min of treatment, indicating that dodine is able to cross the outer and cytoplasmic membranes rather rapidly, and to form, alone or in combination with cell phospholipids and proteins, considerable amounts of triple-layered profiles. In P. syringae cells, saturation levels of dodine corresponded to more than five times the amount needed to form a close-packed monolayer of dodine on the cell surface. The different membranous structures formed in dodine-treated cells, and the coagulation of the cytoplasm, seem to be responsible for the uptake of such high amounts of dodine. The uptake isotherm was essentially Langmuirian. The results presented in this and previous reports indicate that the antibacterial activity of dodine on P. syringae is mainly the result of the action of micelles of the surfactant.

Damage to the cytoplasmic membrane and cell death caused by dodine (dodecylguanidine monoacetate) in Pseudomonas syringae ATCC 12271.

Treatment of Pseudomonas syringae cells with low concentrations of the fungicide dodecylguanidine monoacetate (dodine) resulted in cell death and leakage of K+, UV-absorbing materials, and ribose-containing molecules. The results suggest that dodine causes gross and extensive damage to the cytoplasmic membrane, which is probably implicated in the death of cells.

Tumour incidence in the progeny of male rats exposed to ethylnitrosourea before mating.

BDVI male rats were given a single i.p. dose of 80 mg/kg b.w. ethylnitrosourea (ENU), and each rat was then mated at weeks 1, 2, 3, 4 and 5 after treatment with 3 untreated females. A decrease in the fecundity of the treated males was observed, particularly when they were mated 5 weeks after ENU treatment. The average litter size was lower in the treated group, especially for females mated in week 4. No significant differences in pre- or post-weaning mortality were noted between control and treated groups. A slight, non-significant increase in the incidence of brain tumours was observed in the progeny of treated males compared with the controls. The incidence of thyroid tumours was significantly higher in controls but this difference disappeared when adjustment was made for litter effect and intralitter dependence.

Epidemics due to pesticide contamination of food.

Clinical and epidemiological aspects of epidemics of poisoning due to pesticides are reviewed. The 37 cases chosen are divided into four groups on the basis of implication for prevention.

Induction of potassium efflux by cupric ions in Pseudomonas syringae ATCC 12271 and its correlation with cell viability.

In Pseudomonas syringae, Cu2+ induce a significant loss of K+ from the cells. The course of the efflux followed an approximately sigmoidal pattern. The maximum rate of K+ efflux, the time needed to achieve this rate and the maximum amount of K+ released from the cells, were dependent on copper concentration. Pre-treatment with several divalent cations modified markedly the parameters of potassium efflux induced by copper, by increasing the maximum rate of K+ efflux and the amount of K+ released after 4 min of copper treatment, and decreasing the time required to achieve the maximum rate. The addition of copper to cell suspensions resulted in a progressive decrease in the number of viable cells. Pre-treatment with Mg2+ or Ca2+ resulted in a decrease in the lethality of copper ions.

Los efectos inhibitorios del ethoxiquin sobre la acción carcinogénica de la aflatoxina B1 en las ratas / Inhibitory effects of ethoxyguin on the carcinogenic action of the aflatoxin B1 in female rats

Etoxiquin (EQ), un antioxidante muy frecuentemente utilizado, inhibe los efectos carcinogénicos de los hidrocarburos policiclicos aromáticos. La finalidad de este estudio es determinar si la administración de EQ modifica los efectos hepatocarcinogénicos de la aflatoxina B1 (AFB1) en las ratas. Las ratas, en distintos grupos, recibieron en su dieta, ya sea: (a) EQ durante 2 semanas, seguido de AFB1 durante 6 semanas; (b) EQ y AFB1 simultáneamente; (c) EQ después de terminado el tratamiento con AFB1. Los resultados indican que EQ puede inhibir los efectos hepatocarcinogénicos de la AFB1 y que la inhibicón más efectiva es la que se obtiene cuando EQ y AFB1 son administrados simultáneamente. Nuestros resultados muestran también que el grado de protección desaparece cuando las ratas son tratadas con EQ y luego, durante un período de recuperación de 4 semanas, son sometidas a la dieta de control antes de recibir la AFB1. En este grupo la incidencia de las lesiones neoplásicas en el higado no difiere de la del grupo de ratas que habia recibido solamente AFB1. El efecto inhibitorio del EQ en la carcinogénesis inducida por la AFB1 es de interés. Sin embargo, antes de poder realizar una evaluación global sobre la utilidad de EQ en la quimioprevención es necesario efectuar ulteriores investigaciones