Mn-porphyrins in a four-helix bundle participate in photo-induced electron transfer with a bacterial reaction center.

Hybrid complexes incorporating synthetic Mn-porphyrins into an artificial four-helix bundle domain of bacterial reaction centers created a system to investigate new electron transfer pathways. The reactions were initiated by illumination of the bacterial reaction centers, whose primary photochemistry involves electron transfer from the bacteriochlorophyll dimer through a series of electron acceptors to the quinone electron acceptors. Porphyrins with diphenyl, dimesityl, or fluorinated substituents were synthesized containing either Mn or Zn. Electrochemical measurements revealed potentials for Mn(III)/Mn(II) transitions that are ~ 0.4 V higher for the fluorinated Mn-porphyrins than the diphenyl and dimesityl Mn-porphyrins. The synthetic porphyrins were introduced into the proteins by binding to a four-helix bundle domain that was genetically fused to the reaction center. Light excitation of the bacteriochlorophyll dimer of the reaction center resulted in new derivative signals, in the 400 to 450 nm region of light-minus-dark spectra, that are consistent with oxidation of the fluorinated Mn(II) porphyrins and reduction of the diphenyl and dimesityl Mn(III) porphyrins. These features recovered in the dark and were not observed in the Zn(II) porphyrins. The amplitudes of the signals were dependent upon the oxidation/reduction midpoint potentials of the bacteriochlorophyll dimer. These results are interpreted as photo-induced charge-separation processes resulting in redox changes of the Mn-porphyrins, demonstrating the utility of the hybrid artificial reaction center system to establish design guidelines for novel electron transfer reactions.

Charge regulated solid-liquid interfaces interacting on the nanoscale: Benchmarking of a generalized speciation code (SINFONIA).

Surface chemistry of mineral phases in aqueous environments generates the electrostatic forces involved in particle-particle interactions. However, few models directly take into account the influence of surface speciation and changes in solution speciation when the diffuse layer potential profiles of approaching particles overlap and affect each other. These electrostatic interactions can be quantified, ideally, through charge regulation, considering solution and surface speciation changes upon particle approach by coupling state-of-the-art surface complexation models for the two particle surfaces with a Poisson-Boltzmann type distribution of electrostatic potential and ions in the inter-particle space. These models greatly improve the accuracy of inter-particle force calculations at small inter-particle separations compared to constant charge and constant potential approaches. This work aims at advancing charge regulation calculations by including full chemical speciation and advanced surface complexation models (Basic Stern-, three-, or four plane models and charge distribution concepts), for cases of similar and dissimilar surfaces involving the numerical solution of the Poisson-Boltzmann equation for arbitrary electrolytes. The concept was implemented as a Python-based code and in COMSOL. The flexibility and precision of both, concept and implementations are demonstrated in several benchmark calculations testing the new codes against published results or simulations using established speciation codes, including aqueous speciation, surface complexation and various interaction force examples. Due to the flexibility in terms of aqueous chemistry and surface complexation models for various geometries, a large variety of potential applications can be tackled with the developed codes including industrial, biological, and environmental systems, from colloidal suspensions to gas bubbles, emulsions, slurries like cement paste, as well as new possibilities to assess the chemistry in nano-confined systems.

Novel system configuration with activated sludge like-geometry to develop aerobic granular biomass under continuous flow.

A novel continuous flow system with "flat geometry" composed by two completely mixed aerobic tanks in series and a settler was used to promote the formation of aerobic granular sludge. Making similarities of this system with a typical sequencing batch reactor (SBR), for aerobic granules cultivation, the value of the tank 1/tank 2 vol ratio and the biomass recirculation rate would correspond with the feast/famine length ratio and the length of the operational cycle, respectively, while the settler upflow liquid velocity imposed would be related to the settling time. From the three experiments performed the best results were obtained when the tank 1/tank 2 vol ratio was of 0.28, the sludge recycling ratio of 0.25 and the settler upflow velocity of 2.5 m/h. At these conditions the aggregates had settling velocities between 29 and 113 m/h, sludge volume index at 10 min (SVI10) of 70 mL/g TSS and diameters between 1.0 and 5.0 mm.

Novel polymerase chain reaction primers for the specific detection of bacterial copper P-type ATPases gene sequences in environmental isolates and metagenomic DNA.

AIMS: In the last decades, the worldwide increase in copper wastes release by industrial activities like mining has driven environmental metal contents to toxic levels. For this reason, the study of the biological copper-resistance mechanisms in natural environments is important. Therefore, an appropriate molecular tool for the detection and tracking of copper-resistance genes was developed. METHODS AND RESULTS: In this work, we designed a PCR primer pair to specifically detect copper P-type ATPases gene sequences. These PCR primers were tested in bacterial isolates and metagenomic DNA from intertidal marine environments impacted by copper pollution. As well, T-RFLP fingerprinting of these gene sequences was used to compare the genetic composition of such genes in microbial communities, in normal and copper-polluted coastal environments. New copper P-type ATPases gene sequences were found, and a high degree of change in the genetic composition because of copper exposure was also determined. CONCLUSIONS: This PCR based method is useful to track bacterial copper-resistance gene sequences in the environment. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first to report the design and use of a PCR primer pair as a molecular marker to track bacterial copper-resistance determinants, providing an excellent tool for long-term analysis of environmental communities exposed to metal pollution.

Paradoxical embolism and aortic occlusion: a case report.

This is the case report of a 45-year-old woman who sustained a left popliteal artery embolism. Ten days after popliteal embolectomy, she developed sudden occlusion of the distal aorta. She required a bifemoral embolectomy. Transesophageal echocardiogram demonstrated an atrial septal aneurysm and a septal defect with a right to left shunt. A venogram showed deep venous thrombosis in the right leg as the potential source of the embolism. Paradoxical embolization should be considered when ever an unexplained arterial occlusion occurs, especially in younger patients.

Heat-induced alterations in embryonic cytoskeletal and stress proteins precede somite malformations in rat embryos.

Previous work from this laboratory has demonstrated that heat exposure on gestation day 10 (GD10) resulted in disrupted somite development 24 hr after exposure and subsequent thoracic skeletal malformations in neonates. The purpose of the present study was to examine the effects of in vitro heat shock on de novo protein synthesis and on cytoskeletal protein levels in developing rat embryos. Explanted GD10 embryos were exposed to temperatures of 42-42.5 degrees C for 15 min. At various times postexposure (0-27 hr). embryos were labeled with 35S-methionine and processed for sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) separation. Transient enhanced de novo synthesis of 70- and 90-kD proteins was observed 1-8 hr after exposure. The 70-kD protein was identified as a eukaryotic stress protein and the presence of this protein was detected between 2 and 27 hr posttreatment. Western blot analysis was used to detect quantitative changes in total actin (microfilaments), tubulin (microtubules), and vimentin (intermediate filaments). Immediately following exposure, a reduction of total vimentin to minimal detectable levels was observed in heat-treated embryos. Levels of total vimentin remained depressed for more than 2 hr and gradually returned to control levels 4-8 hr postexposure. No change in total actin or tubulin was detected in treated embryos. The data demonstrate that heat-induced alterations in proteins comprising intermediate filaments occur concomitantly with the induction of stress proteins and precede aberrant somite morphology. These alterations in embryonic proteins may help elucidate the mechanism(s) by which skeletal malformations are produced.

Induction of hsp72 in heat-treated rat embryos: a tissue-specific response.

Previous studies have demonstrated that heat exposure on gestation day 10 (GD10) resulted in disrupted somite development in rat embryos 24 hr after exposure and in thoracic skeletal malformations in neonatal rats examined 3 days postpartum. The production of abnormal somites was correlated with the location of skeletal elements that developed from the affected somites. Heat has also been shown to induce changes in genetic expression whereby new proteins are synthesized and the expression of constituent proteins may be repressed. In the present study, heat-induced alterations in protein synthesis during rat organogenesis that may be associated with previously observed malformation was investigated. GD10 rat embryos were exposed in utero to a heat treatment previously demonstrated to produce skeletal malformations; maternal core temperature was raised and maintained at 42-42.4 degrees C for 5 min. In addition, explanted GD10 embryos were cultured in vitro and exposed to temperatures of 42-42.5 degrees C for 15 min. At various times postexposure, embryos were labeled with 35S-methionine and processed for SDS-PAGE. In both in vivo and in vitro heat-treated embryos, a transient enhanced de novo synthesis of 70- and 90-kD proteins was observed 1-8 hr after exposure. Actinomycin D studies were conducted to determine whether transcription of new mRNA was required for the enhanced synthesis of the 70- and 90-kD proteins in heat-treated embryos. Results from these studies demonstrated that the expression of these proteins was transcriptionally regulated. The 70-kD protein was identified, using Western blot analysis, as a eukaryotic inducible stress protein (hsp72), and the presence of this protein was detected between 2 and 27 hr post-treatment. Immunohistochemical results indicated that following heat shock, hsp72 accumulates in the neuroectodermal tissues of the embryos. The data demonstrate that although heat-induced expression and accumulation of the hsp72 precedes aberrant somite morphology, the lack of hsp72 accumulation in the somite mesoderm may explain the sensitivity of this tissue to heat.

Relationship between abnormal somite development and axial skeletal defects in rats following heat exposure.

The effects of in vivo heat exposure on gestation day (GD) 10 rat embryos were evaluated on GD 11 to determine the relationships between morphological sequelae following in vivo and in vitro exposures and between effects detected on GD 11 and those observed in postnatal day (PND) 3 pups. Anesthetized rats were exposed to 42 degrees C in a warm air incubator until their rectal temperatures reached 41 degrees C or until a rectal temperature of 42-42.5 degrees C had been maintained for 5 minutes. Heat-exposed embryos exhibited a significant decrease in growth parameters including head length, somite number, and protein content/embryo versus controls. These changes correlated well with in vitro effects from an earlier study (G.L. Kimmel et al., '93). Among the morphological endpoints which were slightly delayed in development were the caudal neural tube, branchial bars, forelimb and hindlimb. The only effect on the embryos that could not be explained as a transient delay in development induced by heat was the induction of unsegmented somites. Additional embryos were exposed to 42 degrees C for 15-20 min in vitro and examined specifically for unsegmented somites, which were observed in 47% of embryos exposed to 42 degrees C in vivo or in vitro. This phenomenon was observed in somites 9-20, i.e., those that give rise to cervical and thoracic vertebrae and ribs. These results correlated well with the axial skeletal malformations observed in PND 3 pups exposed to the same heat treatment (C.A. Kimmel et al., '93).

[Polyglobulia and bronchopneumopathies: correlations of ferritin and other ferric parameters with various erythrocytic indexes]. / Poliglobulia y bronconeumopatías: correlaciones de la ferritina y otros parámetros férricos con diversos índices eritrocíticos.

In 15 patients with chronic bronchopneumopathy (7 with polyglobulia and 8 without it), we observed that polyglobulic patients had higher average levels of sideremia and basal saturation of transferrin and lower levels of HCM, CHCM and VCM. No significant differences were observed in the average levels of ferritin between both groups. Overall, in this series of 15 patients, a significant inverse correlation was observed between sideremia and HCM (r = -0.52; p < 0.05) and between sideremia and CHCM (r = -0.55, p < 0.5), as well as a trend towards a direct correlation between sideremia and the red blood cells count (r = 0.45, N.S.). There was also a direct correlation between serum ferritin and the sedimentation rate (r = 0.72, p < 0.01) and trends towards inverse correlations although not significant, between ferritin and sideremia (r = -0.25, N.S.). These data reflect a hyperconsumption of iron in the respiratory polyglobulia, with some relative deficit, suggesting as well that serum ferritin is not a good enough criteria in these cases for the evaluation of iron deposits, because it behaves like the sedimentation rate with respect to acute phase reactants when there is inflammation.

[Biologic behavior of human chorionic gonadotropin hormone (HCGH) in transitional cell carcinomas of the bladder]. / Comportamiento biológico de la hormona gonadotropina coriónica humana (HGCH) en los carcinomas vesicales de células transicionales.

Transitional cell carcinoma of the bladder carries a high rate of local recurrence and 15%-30% of the cases progress to advanced stages of the disease. The multiple forms of the tumor make it difficult to find reliable diagnostic elements of tumor evolution and some authors have advocated the use of tumor markers for the diagnosis and follow-up of malignant bladder tumors. This study was conducted to determine the biological behaviour of the HCG beta subunit it transitional cell carcinoma of the bladder. One hundred patients were entered into the study; the control group comprised 30 healthy subjects and the patient group comprised 70 cases of transitional cell carcinoma of the bladder. The results showed the HCG beta subunit increased with the size and degree of tumor infiltration, although the data were not statistically significant. Similarly, analysis of the degree of tumor differentiation/non differentiation provided no statistically significant data.

Skeletal development following heat exposure in the rat.

The effects of gestation day (GD) 10 heat exposure in the rat were studied to determine the temperature-response relationship for the induction of skeletal and other defects. Conscious pregnant rats (Experiment 1) were exposed to various temperatures in a warm air chamber. Body temperature was measured using a rectal probe, and these measurements were confirmed as representing core body temperature in separate animals using telemetric procedures. Those animals whose core body temperature was raised to 41-41.9 degrees C had over 90% malformed pups (examined at postnatal day (PND) 3), and a 25% reduction in the percent of live pups per litter. Animals whose temperature was raised to 39.2-40.9 degrees C had a low incidence of pups with similar types of malformations. The primary types of malformations were of the axial skeleton, consisting of fusions and other abnormalities of the ribs and vertebral elements, and a decrease in the total number of ribs and centra. The acute maternal effects of these temperature increases were signs of heat exhaustion during and 1-2 hr after exposure, but there were no permanent changes in weight gain or other signs. When temperatures were raised to > or = 42 degrees C, all maternal animals died. In a second study (Experiment 2), pregnant rats (from a different supplier) were anesthetized to determine the effect of reducing maternal stress and were exposed to heat as in Experiment 1. Those animals whose core body temperature was raised to 42-42.5 degrees C for 5 min had pups with similar responses to those in Experiment 1 at 41-41.9 degrees C, although the reduction in litter size was not as great. Animals whose temperature was raised to 41 degrees C had a much lower incidence of pups with similar defects, and animals whose temperature was raised to 43 degrees C did not survive. A more detailed analysis of the skeletal defects in Experiment 2 showed rib and vertebral malformations that appear to be related to the stage of somite development at the time of exposure.

Embryonic development in vitro following short-duration exposure to heat.

Gestation day (GD) 10 rat embryos (10-12 somites) were exposed in vitro for 10 to 25 minutes at 42 or 43 degrees C and evaluated 24 hrs later for alterations in growth and specific morphological parameters, using a modified Brown-Fabro (Brown and Fabro: Teratology, 24:65-78, '81) scoring system that allowed evaluation of development relative to gestational age. At 42 degrees C, crown-rump length appeared to be particularly sensitive, responding to only 10 mins exposure. A 15-min exposure resulted in decreased total protein, somite number and morphological score. No system was uniquely sensitive, since all parameters demonstrated some degree of response. Rather, systems affected were those that would be developing most rapidly at this time in gestation. At 43 degrees C, all of the parameters measured were affected by a 10-min exposure. These results demonstrate alterations in vitro after much shorter exposure periods than previously reported on GD10, which may be due, in part, to the use of a modified scoring system that permitted the evaluation of graded individual end point changes relative to gestational age. The response patterns demonstrated a clear temperature- and exposure duration-dependency, with a shift from a more shallow duration-response curve to a more dramatic inhibition of development as temperature increased from 42 degrees C to 43 degrees C.

Tumor adenomatoide retroperitoneal gigante: a propósito de un caso / Giant retroperitoneal adenomatoid tumor: to purpose of a case

El tumor adenomatoide es el más común de los tumores de los tejidos paratesticulares, especialmente del epidídimo y túnicas testiculares, rara vez del cordón espermático; siendo su diámetro usual de 0.5 cm. El presente es el reporte de un caso de un varón de 30 años quien presentó retención urinaria por compresión de una masa pélvica gigante, lateralizada a la izquierda y que comprimía la vejiga. El urograma excretor y la ecografía localizaron el tumor retroperitonealmente. En la laparatomía se encontró una masa ovoide de aproximadamente 14 cm. de diámetro mayor, de pared blanquesina lisa, renitente, con áreas sólidas que comprimía sigmoide, grandes vasos y desplazaba la vejiga a la derecha. La anatomía patológica correspondio a tumor adenomatoide variedad angiomatoide. Se presenta el caso a propósito de su gran tamaño, su particular localización y lo infrecuente de esta patología.

Lactitol vs. lactulose in the treatment of chronic recurrent portal-systemic encephalopathy.

To compare the efficacy and patient acceptability of lactitol vs. lactulose in chronic recurrent portal-systemic encephalopathy (PSE), 25 cirrhotic patients with a history of repeated episodes of hepatic encephalopathy who required chronic administration of lactulose were included in a controlled cross-over clinical trial in which patients received, at random, lactitol (at an initial dosage of 10 g/6 h) or lactulose (15 ml/6 h, 66% w/v, containing 10 g of lactulose) during a 3 month period and then crossed-over to the alternative treatment for the following 3 months. Doses were adjusted to obtain two bowel movements per day. During the study period the daily protein intake was 40-60 g. Clinical and analytical data (including ammonia levels) were obtained, an EEG and the number connection test were performed and the PSE index was determined before treatment and monthly until the end of the treatment. No significant differences were found between the effects of lactitol and lactulose on the neurological and biological parameters, suggesting that the two treatments could be considered as equally effective. Lactitol was significantly better tolerated than lactulose (P = 0.02), the taste of which was assessed as being too sweet and provoking nausea. In conclusion, lactitol is a good alternative to lactulose for patients with chronic recurrent PSE, especially in those who do not tolerate the excessive sweetness of lactulose.

Cyanamide hepatotoxicity. Incidence and clinico-pathological features.

Ground-glass hepatocytes resembling those seen in HBsAg carriers on hematoxylin and eosin and on trichrome stained sections, but giving a negative reaction to orcein and a positive one to PAS, were found in liver biopsy specimens from nine asymptomatic former alcoholics who were on treatment with cyanamide, in one of four who had been treated with cyanamide several months before the liver biopsy procedure, in none of 15 treated with disulfiram, and in one of eight who had apparently not received aversive drugs. Portal and periportal inflammatory changes and fibrosis were more frequently observed in biopsy specimens containing PAS-positive ground-glass hepatocytes than in those without, but cirrhosis was found with a similar frequency. It is concluded that periportal PAS-positive ground-glass hepatocytes are a histological marker of cyanamide treatment.

Lactitol versus lactulose in the treatment of acute portal systemic encephalopathy (PSE). A controlled trial.

Preliminary data suggest that lactitol (beta-galactoside-sorbitol), a new synthetic non-absorbable disaccharide, has beneficial effects on chronic portal systemic encephalopathy. To compare the efficacy of lactitol vs. lactulose in the treatment of acute portal systemic encephalopathy (PSE), 40 cirrhotic patients with an acute episode of PSE were randomly allocated to one of two groups: group A (20 patients) received lactulose (30 ml/6 h) and group B (20 patients) lactitol (12 g/6 h). These doses were adjusted daily to obtain two bowel movements per day. The duration of treatment was 5 days. Age, sex, hepatic and renal function, precipitating factors and level of PSE measured by clinical examination, EEG and number connection test were similar in the two groups. A complete clinical resolution of PSE occurred in 11 patients in each group. In 5 patients of the lactulose group and in 6 of the lactitol group there was a moderate improvement of PSE during the study. Finally, 4 patients in the lactulose group and 3 in the lactitol group did not respond to treatment. No side effects attributable to therapy were observed in either group. These results indicate that lactitol is as effective as lactulose in the management of patients with cirrhosis and acute PSE.

Serum procollagen type III peptide as a marker of hepatic fibrogenesis in alcoholic hepatitis.

To evaluate if serum procollagen type III peptide levels reflect the extent of liver fibrosis and hepatic collagen synthesis, we have studied 19 patients with histologically proven alcoholic hepatitis and 9 chronic alcoholics with normal liver histology or minimal steatosis. Serum procollagen peptide type III was measured at the time of liver biopsy, and determination of hepatic prolyl-hydroxylase activity, as an index of collagen synthesis, was performed in all liver samples. Hepatic prolyl-hydroxylase activity and serum procollagen peptide levels were significantly higher in patients with alcoholic hepatitis (959 +/- 115 cpm/mg and 33.2 +/- 5.3 ng/ml, respectively) than in alcoholics from the control group (537 +/- 62 cpm/mg and 10.9 +/- 1.5 ng/ml, respectively) (p less than 0.05 and p less than 0.01, respectively). All patients with alcoholic hepatitis had fibrosis (10 mild and 9 severe). Prolyl-hydroxylase activity and procollagen peptide levels were significantly higher in alcoholic hepatitis patients with severe fibrosis than in those with mild fibrosis (1208 +/- 154 cpm/mg vs. 734 +/- 138 cpm/mg, p less than 0.05 and 49.1 +/- 8.8 ng/ml vs. 20.4 +/- 2.6 ng/ml, p less than 0.01). Furthermore, a close correlation was found between the hepatic prolyl-hydroxylase activity and the serum level of procollagen peptide (r = 0.76, p less than 0.001). We conclude that the serum procollagen peptide level is a good marker of hepatic fibrogenesis in alcoholic hepatitis; thus, its serial measurement could be useful in identifying patients in progress to cirrhosis and in assessing the therapeutic efficiency of antifibrogenic drugs.

Measurement of fibrosis in needle liver biopsies: evaluation of a colorimetric method.

Collagen content was measured in 38 needle liver biopsies (8 steatosis, 8 chronic hepatitis, 7 fibrosis and 15 cirrhosis) by a new colorimetric method based on the selective capacity of Sirius red and Fast green to bind to collagen and noncollagenous proteins, respectively. The values were compared with those obtained after determination of the degree of fibrosis by morphometry in the same tissue. In biopsies with cirrhosis and fibrosis, there was a higher amount of collagen than in biopsies with chronic hepatitis and steatosis. Furthermore, there was a highly significant direct correlation between the collagen content measured colorimetrically and the degree of fibrosis determined morphometrically (r = 0.77, p less than 0.001), suggesting that this new colorimetric method is useful in measuring the degree of fibrosis in needle liver biopsies.