Ingestion of paralytic shellfish toxins in a carnivorous gastropod (Chorus giganteus): effects on their elemental composition and reproductive traits

The producer of paralytic shellfish toxin (PST), Alexandrium catenella, is one of the main generators of HABs in the coasts of Chile. Its presence produces ecological and economic damage, directly affecting filter-feeding organisms, and indirectly to other organism through the trophic chain. The objective of this research was to identify the effect of a toxic diet on the energetic and reproductive parameters of the carnivorous snail Chorus giganteus. Two groups of snails were used, one fed with toxic prey (bivalves fed with A. catenella), and the other fed with non-toxic prey. Both treatments were maintained under these conditions for 63 days, then, elemental composition (C, N) and energy content were estimated, and fecundity parameters were analyzed. The results indicate that snails fed with toxic prey had a lower percentage of C and C/N ratio. The energy content was significantly lower in intoxicated snails. Regarding fecundity parameters, a higher number of egg-masses were produced by toxic snails, however, only 62% of these showed embryonic development, with 57% hatching success. A negative relationship was identified between the mean PST concentration, quantified in snails, and the number of egg-masses produced per aquarium. In the aquarium where the snails had highest average PST concentration (1200 ± 820 μg STX.2HCL eq. Kg-1) there was no oviposition, while egg-masses were only produced by snails in aquaria where the average concentration did not exceed 360 ± 160 μg STX.2HCL eq. Kg-1. It is likely that, with low levels of accumulated PST, C. giganteus activates its oviposition process as a response to toxin-induced stress, generating a higher energy expenditure supported by a redirection of its reserves. However, when the intoxication presents higher levels, the reproductive process could be inhibited, similar to what has been identified in other molluscs.

Effects of ocean acidification and warming on physiological and behavioural responses of an herbivore snail to waterborne predator cues

Ocean Acidification (OA) and Ocean Warming (OW) represent major climate stressors that may disrupt species interactions. However, despite the knowledge about the impacts of OA and OW on the performance of individual species, it is still unclear how biological interactions can be modified by the combined effects of these stressors. Consequently, in this study, we assess the effects of changes in temperature (12 °C and 20 °C) and pCO2 (500 and 1600 μatm) levels in seawater, along with the presence/absence of waterborne cues from the predator crab Homalaspis plana on the physiological and behavioural performance of the snail Tegula atra. Snail consumption rate was positively affected by OW and negatively by predator cues whereas absorption efficiency (AE) was positively affected by OW without interactions among these stressors. Oxygen uptake of snails reared in OW conditions was greater than those in control conditions, but only at control pCO2 levels. When pCO2 level was also raised, the positive effect of warmer temperature on oxygen uptake was reduced. While biomass was negatively affected by OW, OA and predator cues, without interactions. In the presence of predator cues the self-righting times of snails were significantly slower in individuals reared at OW conditions. Additionally, OA and OW conditions do not affect the prey hunting, efficiency (consumption) and preference, and claw strength of the predatory crab. These results indicate that OA and OW affect physiological and behavioral traits of snails but no the predatory behavior of crab. This environmentally-induced decoupling of co-evolutionary predator-prey dynamics may have important consequences on the structure and stability of coastal communities and ecosystems under the influence of climate change.

Upwelling as a stressor event during embryonic development: Consequences for encapsulated and early juvenile stages of the marine gastropod Acanthina monodon

Upwelling phenomena alter the physical and chemical parameters of the sea's subsurface waters, producing low levels of temperature, pH and dissolved oxygen, which can seriously impact the early developmental stages of marine organisms. To understand how upwelling can affect the encapsulated development of the gastropod Acanthina monodon, capsules containing embryos at different stages of development (initial, intermediate and advanced) were exposed to upwelling conditions (pH = 7.6; O2 = 3 mg L-1; T° = 9 °C) for a period of 7 days. Effects of treatment were determined by estimating parameters such as time to hatching, number of hatchlings per capsule, percentage of individuals with incomplete development, and shell parameters such as shell shape and size, shell strength, and the percentage of the organic/inorganic content. We found no significant impacts on hatching time, number of hatchlings per capsule, or percentage of incomplete development in either the presence or absence of upwelling, regardless of developmental stage. On the other hand, latent effects on encapsulated stages of A. monodon were detected in embryos that had been exposed to upwelling stress in the initial embryonic stage. The juveniles from this treatment hatched at smaller sizes and with higher organic content in their shells, resulting in a higher resistance to cracking 30 days after hatching, due to greater elasticity. Geometric morphometric analysis showed that exposure to upwelling condition induced a change in the morphology of shell growth in all post-hatching juveniles (0-30 days), regardless of embryonic developmental stage at the time of exposure. Thus, more elongated shells (siphonal canal and posterior region) and more globular shells were observed in newly hatched juveniles that had been exposed to the upwelling condition. The neutral or even positive upwelling exposure results suggests that exposure to upwelling events during the encapsulated embryonic phase of A. monodon development might not have major impacts on the future juvenile stages. However, this should be taken with caution in consideration of the increased frequency and intensity of upwelling events predicted for the coming decades.

Embryonic encapsulated development of the gastropod Acanthina monodon is impacted by future environmental changes of temperature and pCO2

Egg capsules of the gastropod Acanthina monodon were maintained during the entire period of encapsulated development at three temperatures (10, 15, 20 °C) and two pCO₂ levels (400, 1200 μatm). Embryos per capsule, size at hatching, time to hatching, embryonic metabolic rates, and the resistance of juveniles to shell breakage were quantified. No embryos maintained at 20 °C developed to hatching. The combination of temperature and pCO₂ levels had synergistic effects on hatching time and developmental success, antagonistic effects on number of hatchlings per capsule, resistance to juvenile shell cracking and metabolism, and additive effect on hatching size. Juveniles hatched significantly sooner at 15 °C, independent of the pCO₂ level that they had been exposed to, while individuals hatched at significantly smaller sizes if they had been held under 15 °C/1200 μatm rather than at 10 °C/low pCO₂. Embryos held at the higher pCO₂ had a significantly greater percentage of abnormalities. For capsules maintained at low pCO₂ and 15 °C, emerging juveniles had less resistance to shell breakage. Embryonic metabolism was significantly higher at 15 °C than at 10 °C, independent of pCO₂ level. The lower metabolism occurred in embryos maintained at the higher pCO₂ level. Thus, in this study, temperature was the factor that had the greatest effect on the encapsulated development of A. monodon, increasing the metabolism of the embryos and consequently accelerating development, which was expressed in a shorter intracapsular development time, but with smaller individuals at hatching and a lower resistance of their shells to breakage. On the other hand, the high pCO₂ level suppressed metabolism, prolonged intracapsular development, and promoted more incomplete development of the embryos. However, the combination of the two factors can mitigate--to some extent--the adverse effects of both incomplete development and lower resistance to shell breakage.

The paralytic shellfish toxin effect on bioenergetic constituents of the fishery resource Chorus giganteus (Gastropoda: Muricidae)

Alexandrium catenella, one of the most common harmful microalgae observed in southern Chile, produces paralytic shellfish toxins, which can affect many organisms throughout the trophic chain. This research evaluated how paralytic shellfish toxins affected the principal bioenergetic constituents and fatty acids composition of the carnivorous snail Chorus giganteus. Snails were separated into a "toxic" group that was fed the toxic clam Mulinia edulis (which was previously fed A. catenella), and a "non-toxic" group, fed non-toxic clams. Both groups were kept under these conditions for 63 days. Our results indicated no difference in the ingestion rate of toxic versus non-toxic snails; however, a higher protein level was identified in toxic snails. The total lipid content proved to be no different in toxic versus non-toxic snails; although, an effect of the toxic diet on the fatty acid profile of C. giganteus was observed. High levels of essential polyunsaturated fatty acids, especially docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) in toxic snails, were identified. Our results suggest that exposure to paralytic shellfish toxins, through diet, may cause changes in the biochemical composition of C. giganteus, which may have a subsequent impact on its energetic physiology.

Long-term effects of contrasting pCO2 levels on the scope for growth in the carnivorous gastropod Concholepas concholepas

We evaluated the effect of contrasting pCO₂ levels: lower (390 μatm), moderate (700 μatm) and extreme (1000 μatm), on the scope for growth of the keystone snail Concholepas concholepas over an exposure period of 6 months. Juvenile snails were collected from rocky intertidal habitats and acclimated for 5 months to those pCO₂ levels. Subsequently, three groups of snails were randomly taken (n = 7 for each treatment) and reared for an additional 1 month for each of the three pCO₂ levels. Physiological traits related with energy gain and energy expenditure were quantified. The scope for growth index decreased significantly with increases in pCO₂, yielding negative values throughout the experimental period for the snails exposed to 1000 μatm pCO₂, probably due to the extra energy required to maintain their metabolic functions in balance. This suggests that future climate change scenarios with elevated pCO₂ levels could threaten the growth and other basic functions of juvenile snails of this species.

CLINICAL RESULTS AND COST EFFECTIVENESS OF RADIOFREQUENCY AND CYANOACRYLATE COMPARED WITH TRADITIONAL STRIPPING FOR TREATING VARICOSE VEINS

BACKGROUND

Disease of the venous system is an underappreciated public health problem. Minimally invasive treatments based on radiofrequency ablation (RFA) or cyano-acrylate adhesive ablation (CA) have almost entirely replaced surgical stripping (SS) of the great and small saphenous veins.

OBJECTIVE

The purpose of this study is to compare the outcome 3 years after SS, RFA, or CA by assessing complications and reintervention and performing a cost-effectiveness analysis.

METHODS

Between February 2016 and February 2019, all consecutive patients with symptomatic varicose veins from the Vascular Department of two hospitals who were treated with SS, RFA or CA were included in the study. The clinical outcomes were measured by quality-adjusted life years (QALYs), complications and reintervention. A comparison with conservative treatment was also performed. A detailed resource use was recorded for each procedure. All costs were normalized to May 2020 US dollars and euros. Analysis of the data was by treatment received. All statistical tests were two-sided, and the significance level was set at 5%. Two perspectives of the analysis were considered: the social perspective and that of the Spanish Public Health System (SPHS). The time horizon was 3 years. No discount rate was applied.

RESULTS

A total of 233 patients were enrolled in this study: 90 SS (38.6%), 93 RFA (39.9%), and 50 CA (21.5%). There were 11 complications in the SS group (12.2%) vs. 3 (3.3%) with RFA and 3 (6%) with CA (p = 0.06). There were no cases of reinterventions. The median loss of workdays was 15 days for SS (IQR 10-30), 0 days for RFA (IQR 0-6), and 0 for CA (IQR 0-1) groups, respectively (p < 0.001). The median level of satisfaction for SS was 9 (IQR 8-10), 10 for RFA (IQR 9-10), and also 10 for CA (IQR 9-10) (p < 0.001). The QALYs was 2.6 years for all three procedures. The medians overall cost is €852/US$926 for SS, €1002/US$1089 for RFA and €1228.3/US$1335 for CA. The total cost per QALY is 323 €/QALY (351US$/QALY) for SS; 380 €/QALY (413US$/QALY) for RFA and 467 €/QALY (508US$/QALY) for CA. Indirect cost was measured by workdays lost cost for each patient, for SS was €1527 (US$1660) (IQR 1018-3054); 0€ (IQR 0- 611) for RFA and 0€ (IQR 0-102) for CA (p < 0.001).

CONCLUSIONS

All three techniques were cost effective (procedures are recommended with an incremental cost-effectiveness ratio under 30,000€/QALY). From the SPHS perspective, when considering only health care costs, the most cost-effective technique was SS. From the social perspective, including the opportunity cost of medical leave, CA was the most cost-effective technique, saving €1600 per patient, a cost that more than compensates for the savings of SS in direct healthcare costs.

The osmotic response capacity of the Antarctic fish Harpagifer antarcticus is insufficient to cope with projected temperature and salinity under climate change

Over the last decades, climate change has intensified. Temperatures have increased and seawater has become "fresher" in Antarctica, affecting fish such as Harpagifer antarcticus. Thus, this study aimed to evaluate changes in the osmoregulatory response of the Antarctic notothenioid fish Harpagifer antarcticus and evaluate how it will cope with the future climate change and environmental conditions in the Antarctic, and in the hypothetical case that its geographical distribution will be extended to the Magellanes region. The present study was undertaken to determine the interaction between temperature and salinity tolerance (2 °C and 33 psu as the control group, the experimental groups were 5, 8, and 11 °C and 28 and 23 psu) and their effect on the osmoregulatory status of H. antarcticus. We evaluated changes in gill-kidney-intestine NKA activity, gene expression of NKAα, NKCC, CFTR, Aquaporins 1 and 8 in the same tissues, muscle water percentage, and plasma osmolality to evaluate osmoregulatory responses. Plasma osmolality decreased with high temperature, also the gill-kidney-intestine NKA activity, gene expression of NKA α, NKCC, CFTR, Aquaporins 1, and 8 were modified by temperature and salinity. We demonstrated that H. antarcticus can not live in the Magallanes region, due to its incapacity to put up with temperatures over 5 °C and with over 8 °C being catastrophic.

Respiratory and desiccation constraints during encapsulated intertidal development of the marine gastropod Acanthina monodon

Acanthina monodon commonly deposits its egg capsules in the intertidal zone. Capsule aerial exposure during low-tide can impact oxygen consumption rates (OCR) of embryos and intracapsular oxygen availability, and expose embryos to desiccation. OCR increased as embryonic development progressed, and was greater when capsules were submerged in seawater than when exposed to air. Oxygen available within the capsule was always less than that available in the immediate external environment, whether capsules were immersed or exposed. The highest internal oxygen concentrations were recorded during periods of air exposure for embryos in more advanced development stages. When exposed to air, capsules lost water the fastest when they contained early embryos, and suffered the highest mortalities following exposure. Collectively, these data suggest that, although encapsulation helps the embryos to develop across wildly fluctuating environmental conditions, the amount of stress the embryos experience will vary depending on their exact positioning within the intertidal zone.

The energetic physiology of juvenile mussels, Mytilus chilensis (Hupe): The prevalent role of salinity under current and predicted pCO2 scenarios

As a result of human activities, climate forecasts predict changes in the oceans pCO₂ and salinity levels with unknown impacts on marine organisms. As a consequence, an increasing number of studies have begun to address the individual influence of pCO₂ and salinity but much remains to be done to understand their combined effects on the physiology and ecology of marine species. Our study addressed this knowledge gap by measuring the influence of current and predicted levels of pCO₂ (380 and 1200 ppm, respectively) and salinity (20, 25 and 30 psμ) on the energetic physiology of juvenile mussels (Mytilus chilensis) from the south-eastern Pacific region. Our results indicate that a reduced salinity caused a significant reduction in clearance rate, absorption efficiency and scope for growth of this species. Meanwhile, an increase in pCO₂ levels caused a reduction in excretion rates and interacted significantly with salinity in the rate of oxygen uptake measured in the mussel. These results suggest that potential changes in salinity might have a direct role on the physiology of M. chilensis. The effect of pCO₂, although less prevalent among the variables measured here, did interact with salinity and is also likely to alter the physiology of this species. Given the ecological and economic importance of M. chilensis, we call for further studies exploring the influence of pCO₂ across a wider range of salinities.

Volcanic ash in the water column: Physiological impact on the suspension-feeding bivalve Mytilus chilensis

Ashes settling into the sea from volcanic explosions expose suspension-feeding species to reduced seston quality. Adults and juveniles of the mussel Mytilus chilensis were exposed for 15days to the phytoplankton Isochrysis galbana together with various concentrations of ashes. We then quantified impact on survival and physiology. Although no individuals died during the experiment, by the end of the study clearance rates and oxygen consumption rates had decreased substantially, and tissue weight of mussels exposed to the highest ash concentrations declined substantially. Gills showed no physical damage, but did show abundant mucus secretion in response to ash particles. Moreover, as the relative proportions of microalgae to ash in the diet decreased, individuals showed increasing preferential ingestion of microalgal particles. Increased ash content in the diet altered physiological rates and activated distinct particle selection with a high production of pseudofeces and high energy costs, with potential long-term consequences.

Comparison between urine culture profile and morphology classification using fluorescence parameters of the Sysmex UF-1000i urine flow cytometer

AIMS

To determine the usefulness of the fluorescence parameters generated by Sysmex UF-1000i flow cytometer for the rapid diagnosis of urinary tract infection by bacilli or cocci.

METHODS AND RESULTS

Urine samples (n = 1924) were studied by culture and microbiology and subsequently by cytometry, using BACT-Morph software and considering forward-scattered light (FSC) and fluorescent light scatter fluorescence parameters. BACT-Morph software showed moderate diagnostic accuracy (78·4%) to detect rod-shaped bacteria, with sensitivity of 82·4% and specificity of 62·5%. Forward-scattered (B_FSC) values of the bacterial channel were significant higher for the Gram-positive cocci category (P < 0·001). A cut-off of B_FSC ≥24·2, expressed in arbitrary units (analytical channel, ch), provided higher sensitivity (90·0%) but lower specificity (38·9%), and the diagnostic accuracy for Gram-positive cocci classification reached 62·0%.

CONCLUSIONS

Utilization of BACT-Morph software and bacterial channel fluorescence parameters (B_FSC ≥24·2 ch) offered an approximate discrimination of bacilli and cocci but the specificity was low, especially for FSC.

SIGNIFICANCE AND IMPACT OF THE STUDY

Further research is needed to establish the usefulness of flow cytometry for aetiological diagnosis.

Distinct phenotype of hepatotoxicity associated with illicit use of anabolic androgenic steroids

BACKGROUND

We have observed an increase in hepatotoxicity (DILI) reporting related to the use of anabolic androgenic steroids (AAS) for bodybuilding.

AIM

To characterise phenotype presentation, outcome and severity of AAS DILI.

METHODS

Data on 25 cases of AAS DILI reported to the Spanish (20) and Latin-American (5) DILI Registries were collated and compared with previously published cases.

RESULTS

AAS DILI increased from representing less than 1% of the total cases in the Spanish DILI Registry in the period 2001-2009 to 8% in 2010-2013. Young men (mean age 32 years), requiring hospitalisation, hepatocellular injury and jaundice were predominating features among the AAS cases. AAS DILI caused significantly higher bilirubin values independent of type of damage when compared to other drug classes (P = 0.001). Furthermore, the cholestatic AAS cases presented significantly higher mean peak bilirubin (P = 0.029) and serum creatinine values (P = 0.0002), compared to the hepatocellular cases. In a logistic regression model, the interaction between peak bilirubin values and cholestatic damage was associated with the development of AAS-induced acute kidney impairment (AKI) [OR 1.26 (95% CI: 1.035-1.526); P = 0.021], with 21.5 ×ULN being the best bilirubin cut-off point for predicting AKI risk (AUCROC 0.92). No fatalities occurred.

CONCLUSIONS

Illicit recreational AAS use is a growing cause of reported DILI that can lead to severe hepatic and renal injury. AAS DILI is associated with a distinct phenotype, characterised by considerable bilirubin elevations independent of type of damage. Although hepatocellular injury predominates, acute kidney injury develops in cholestatic cases with pronounced jaundice.

Hepatotoxicity associated with statin use: analysis of the cases included in the Spanish Hepatotoxicity Registry

OBJECTIVES

The hepatotoxic potential of statins is controversial. The objectives of this study were to describe the relative frequency of hepatotoxicity caused by statins and the phenotypes found in Spain.

PATIENTS AND METHODS

The incidence of hepatotoxicity attributed to statins in the Spanish Hepatotoxicity Registry (REH) were studied and compared with those attributed to other drugs.

RESULTS

Between April 1994 and August 2012, the REH included a total of 858 cases of which 47 (5.5 %) were attributed to statins. Of these, 16 were due to atorvastatin (34 %); 13 to simvastatin (27.7 %); 12 to fluvastatin (25.5 %); 4 to lovastatin (8.5 %) and 2 to pravastatin (4.3 %). Statins represented approximately half of the cardiovascular group which occupied 3rd place (10 %), after anti-infectious agents (37 %) and central nervous system drugs (14 %). The hepatocellular pattern was predominant, especially in the simvastatin group (85%), the cholestatic/mixed pattern was more frequent with fluvastatin (66 %) and had a similar distribution to atorvastatin. Patients with statin-induced toxicity were older (62 years versus 53 years, p < 0.001) and more often demonstrated anautoimmune hepatitis phenotype (8.5 % versus 1.4 %, p < 0.003).

CONCLUSIONS

Statins are not a common cause of hepatotoxicity in Spain. Atorvastatin is the statin involved in the greatest number of incidents. The liver injury pattern varies among the different statins. The hepatitis phenotype with autoimmune features appears to be a characteristic signature of statin-induced hepatotoxicity.

Viral infections of the central nervous system in Spain: a prospective study

The aim of the study was to determine the incidence of viruses causing aseptic meningitis, meningoencephalitis, and encephalitis in Spain. This was a prospective study, in collaboration with 17 Spanish hospitals, including 581 cases (CSF from all and sera from 280): meningitis (340), meningoencephalitis (91), encephalitis (76), febrile syndrome (7), other neurological disorders (32), and 35 cases without clinical information. CSF were assayed by PCR for enterovirus (EV), herpesvirus (herpes simplex [HSV], varicella-zoster [VZV], cytomegalovirus [CMV], Epstein-Barr [EBV], and human herpes virus-6 [HHV-6]), mumps (MV), Toscana virus (TOSV), adenovirus (HAdV), lymphocytic choriomeningitis virus (LCMV), West Nile virus (WNV), and rabies. Serology was undertaken when methodology was available. Amongst meningitis cases, 57.1% were characterized; EV was the most frequent (76.8%), followed by VZV (10.3%) and HSV (3.1%; HSV-1: 1.6%; HSV-2: 1.0%, HSV non-typed: 0.5%). Cases due to CMV, EBV, HHV-6, MV, TOSV, HAdV, and LCMV were also detected. For meningoencephalitis, 40.7% of cases were diagnosed, HSV-1 (43.2%) and VZV (27.0%) being the most frequent agents, while cases associated with HSV-2, EV, CMV, MV, and LCMV were also detected. For encephalitis, 27.6% of cases were caused by HSV-1 (71.4%), VZV (19.1%), or EV (9.5%). Other positive neurological syndromes included cerebellitis (EV and HAdV), seizures (HSV), demyelinating disease (HSV-1 and HHV-6), myelopathy (VZV), and polyradiculoneuritis (HSV). No rabies or WNV cases were identified. EVs are the most frequent cause of meningitis, as is HSV for meningoencephalitis and encephalitis. A significant number of cases (42.9% meningitis, 59.3% meningoencephalitis, 72.4% encephalitis) still have no etiological diagnosis.

Performance of the Sysmex UF1000i system in screening for significant bacteriuria before quantitative culture of aerobic/facultative fast-growth bacteria in a reference hospital

OBJECTIVE

To evaluate the performance of the Sysmex UF1000i automatic urine screening system in the quantitative culture of fast-growth aerobic/facultative bacteria.

METHODS AND RESULTS

A standard procedure was used to recover fast-growth aerobic/facultative micro-organisms in 1225 samples, applying (Sysmex(®)) flow cytometry for parallel bacteria and leucocyte counts. According to the area under the receiver operating characteristic curve, the optimal cut-off values to detect bacteriuria >10(5) colony forming units (CFU) ml(-1) were 690/μl for bacteria and 38/μl for leucocytes (sensitivity, 92%; specificity, 65%; positive predictive value [PPV], 39%; and negative predictive value [NPV], 97%). The use of a single cut-off point of 150 bacteria μl(-1) to detect significant bacteriuria of >10(5) CFU ml(-1) or of ≥10(4) CFU ml(-1) plus leucocyturia obtained similar results (sensitivity, 89%; specificity, 54%; PPV, 31%; and NPV, 96%) and allowed 45.7% of the samples to be rapidly excluded.

CONCLUSIONS

The Sysmex UF1000i system can be adapted for bacteriuria screening by the use of an appropriate cut-off point.

SIGNIFICANCE AND IMPACT OF THE STUDY

This screening system significantly reduces the workload and produces very few false positives and negatives.

[Liver injury induced by "natural remedies": an analysis of cases submitted to the Spanish Liver Toxicity Registry]

BACKGROUND

toxic liver damage associated with the use of natural remedies is a growing health problem.

OBJECTIVES

to analyze the demographics, and clinical and epidemiological characteristics of patients developing liver injury related to these remedies.

PATIENTS AND METHODS

all DILI cases associated with the use of herbal remedies (HR) or dietary supplements (DS) submitted to the Spanish Registry were analyzed. Type of liver damage, severity, and outcome were specifically evaluated.

RESULTS

thirteen cases out of 521 DILI cases (2%) submitted to the Spanish Liver Toxicity Registry between 1994 and 2006 were related to HR/DS, which ranked as the 10th therapeutic group with a greater number of cases and above pain killers, anxiolytics, and antipsychotic drugs. Nine patients (69%) were female (mean age 45 years). Nine cases (69%) had jaundice at presentation. The predominating type of liver damage was hepatocellular (12; 92%), and 31% of cases exhibited the common features of hypersensitivity. Camellia sinensis (3, 23%) was the main causative herb, followed by Rhamnus purshianus and isoflavones (Fitosoja(R), Biosoja(R)) (2 cases each, 15%). Three cases (23%) were rechallenged with the offending product.

CONCLUSIONS

the incidence of hepatic damage related to HR/DS is not so rare, the most common profile of affected patients being a woman with acute hepatocellular hepatitis. Low suspicion regarding the putative role of herbs in hepatotoxicity makes diagnosis more difficult, and probably increases the incidence of inadvertent rechallenge in these patients.

[Sacral root neuromodulation as treatment for fecal incontinence. Preliminary results]

We present our initial experience in the treatment of fecal incontinence (FI) with sacral root neuromodulation (SRN) by reporting the results of a prospective study with 26 patients where baseline Wexner-Cleveland scale scores and ability to delay defecation were compared to results after one year with SRN. The initial study of patients included history taking, general examination, anal ultrasonography, and manometry, and a three-week diary of continence and quality of life specific for FI was used. Before SRN the mean baseline Wexner-Cleveland score was 15.00 +/- 1.81, and 62.50% of patients could only delay defecation for less than a minute. After a year with NRS the mean Wexner-Cleveland score was 4.87 +/- 2.54 (p = 0.0031), and 75.01% of patients could delay defecation above fifteen minutes (p = 0.0018). We also describe the surgical technique and its indications, and finally review the various therapeutical options for FI and show our algorithm for this condition. SRN is an effective technique for the treatment of FI in properly selected patients with no response to medical therapies (including biofeedback) or anatomic correction (sphincteroplasty), with efficacy, little morbidity, and a short hospital stay.

Trophic interactions between the toxic dinoflagellate Alexandrium catenella and Mytilus chilensis: feeding and digestive behaviour to long-term exposure

Trophic interactions between Mytilus chilensis and the toxic dinoflagellate Alexandrium catenella were studied over a 21-day period to determine the absorption kinetics of biochemical components and the enzymatic activity of the digestive gland (i.e. amylase, cellulase complex, laminarinase and protease). For the duration of the experiment, logarithmic relationships were established for the assimilatory balance and carbohydrase activities (amylase, laminarinase and cellulase) of the mussels fed with a toxic diet. The study shows that M. chilensis was able to develop mechanisms which allow exploitation of the toxic microalgae as a food source, despite that its feeding and digestive processes were affected during the first days of contamination.

Deficit irrigation and rootstock: their effects on water relations, vegetative development, yield, fruit quality and mineral nutrition of Clemenules mandarin

Differences between rootstocks, 'Cleopatra' mandarin and 'Carrizo' citrange, in soil-plant water relations and the influence of these factors on vigor, crop yield, fruit quality and mineral nutrition were evaluated in field-grown Clemenules mandarin trees irrigated at 100% of potential seasonal evaporation (ET(c)) (control treatment), or irrigated at 100% ET(c), except during Phases I and III of fruit growth and post-harvest when no irrigation was applied (deficit irrigation (DI) treatment), for 3 years. Differences between rootstocks in plant-soil water relations were the primary cause of differences among trees in vegetative development and fruit yield. After 3 years of DI treatment, trees on 'Cleopatra' showed more efficient soil water extraction than trees on 'Carrizo', and maintained a higher plant water status, a higher gas exchange rate during periods of water stress and achieved faster recovery in gas exchange following irrigation after water stress. The DI treatment reduced vegetative development more in trees on 'Carrizo' than in trees on 'Cleopatra'. Cumulative fruit yield decreased more in DI trees on 'Carrizo' (40%) than on 'Cleopatra' (27%). The yield component most affected by DI in 'Cleopatra' was the number of fruit, whereas in 'Carrizo' it depended on the severity of water stress reached in each phase (severe water stress in Phase I affected mainly the number of fruit, whereas it affected fruit size the most in Phase III). In the third year of DI treatment, water-use efficiency decreased sharply in trees on 'Carrizo' (70%) compared to trees on 'Cleopatra' (30%). Thus, trees on 'Cleopatra' were able to tolerate moderate water stress, whereas trees on 'Carrizo' were more sensitive to changes in soil water content.

Is anal endosonography useful in the study of recurrent complex fistula-in-ano?

INTRODUCTION

performing anal endosonography in complex fistula-in-ano allows us to design a personalized surgical strategy in each case, thereby improving results. However, there are doubts in the literature as to its utility in recurrent complex fistulas. The aim of this study was to compare the utility of anal ultrasonography in the study of primary versus recurrent complex fistula-in-ano.

PATIENTS AND METHOD

prospective study of patients diagnosed and treated for complex fistula-in-ano. Physical examination and anal ultrasonography provided data on primary track, internal opening, horseshoe extension and the presence of secondary tracks or cavities in a protocol designed specifically for the study. These assessments were subsequently contrasted with operative findings.

RESULTS

we included 35 patients, 19 (54.3%) with primary complex anal fistulas and 16 (45.7%) with recurrent fistulas. According to the operative findings, fistulas were classified as high transsphincteric in 28 patients (80%), suprasphincteric in 6 (17.1%) and extrasphincteric in one patient (2.9%), with no differences between groups. Physical examination correctly classified 28 of the 35 fistulous tracks, in contrast to the 32 (91.4%) correctly described on ultrasonography (80%). We did not find any statistically significant differences between the primary and the recurrent fistula groups with regard to sensibility, positive predictive value and accuracy of the anal ultrasonography for any of the parameters studied.

CONCLUSION

the accuracy of anal ultrasonography does not decrease in recurrent complex fistula-in-ano.

Incidence and severity of infections according to the development of neutropenia during combined therapy with pegylated interferon-alpha2a plus ribavirin in chronic hepatitis C infection

The evolution of treatment of chronic hepatitis C virus infection has led to improved therapeutic efficacy. However, a major problem is the presence of side effects that require modification or withdrawal of drug therapy in 15-20% of cases. This could potentially influence the lack of sustained viral response in 50% of the cases. Side effects are common, even with pegylated interferon. This study aimed to assess the incidence and severity of infections based on the development of neutropenia associated with combined therapy with pegylated interferon-alpha2a plus ribavirin in 209 patients with chronic hepatitis C infection. All patients were administered pegylated interferon-alpha2a (180 microg/week) plus ribavirin (800 mg/day for 24 weeks in cases of nongenotype 1, or 1000-1200 mg/day for 48 weeks for genotype 1, according to whether patients weighed more or less than 75 kg). Patients with preexisting neutropenia of any cause or cirrhosis were excluded. Neutropenia was defined as a neutrophil count (NC) of <1500 cells/microl. Neutropenia was classified into three levels during treatment: 750<or=NC<1500 (level 1), 500<or=750 (level 2), and NC<500 cells/microl (level 3). Of the 209 patients, 114 did not develop neutropenia (mean 2100+/-804 cells/microl), while 95 had an NC<1500 cells/microl (mean 1100+/-250 cells/microl). It was found that patients who developed neutropenia during treatment of chronic hepatitis C virus infection with a combined therapy based on pegylated interferon-alpha2a plus ribavirin did not show a higher infection rate or increased severity of the disease.

Enzymatic and feeding behaviour of Argopecten purpuratus under variation in salinity and food supply

Argopecten purpuratus is a bivalve filter feeder inhabiting protected areas of the Peruvian coastline and northern and central Chile. The species is commercially valuable and the natural stocks are over-exploited in Chile, mainly in the central region. Expansion of aquaculture farms to the geographically protected coastline of southern Chile is a potential solution to this problem. So, the objective of the present study was to determine the acute feeding and digestive response of A. purpuratus in relation to short acclimation periods (1, 3 and 7 days) and exposure to variable salinity (24 per thousand, 27 per thousand and 30 per thousand) with two different diets. The feeding behaviour of A. purpuratus follows that described for other species of bivalves whereby the decrease in salinity produces a reduction in the clearance and ingestion rates. This behaviour is not affected by the diet type or the 7 day acclimation period. Lower values of absorption efficiency are associated with increasing food concentration. The response of the AE at 24 per thousand salinity and low organic content diet indicates that the interaction of low salinity and low organic content diet reduces the AE to values approaching zero. The enzymatic investment of A. purpuratus at low salinity (24 per thousand) is similar for both diets and more reduced than for 30 per thousand and 27 per thousand salinity. The results show that osmotic stress leads to a reduction of the enzymatic response capacity. The multiple regression analysis indicates that different responses are observed as a function of the enzymatic activity and the organ. A reduction of the carbohydrase activities in the digestive gland was observed to low salinity (24 per thousand), specifically amylase and celullase. The results of this study are ecophysiologically relevant and highlight a relationship between digestive enzymatic activity and salinity, and may explain the possible differences in the energetic balance of A. purpuratus in response to changes in salinity.

Dielectric monitoring of growth and sporulation of Bacillus thuringiensis

On-line permittivity and optical density measurements have been used to monitor biomass concentration and sporulation status during growth of a spore-forming bacterium, Bacillus thuringiensis, in fed-batch culture. The correlation between permittivity, optical density and other observations showed three distinct phases of growth: growth itself, transition and sporulation. The permittivity variations during the transition and sporulation phases could be related to the sporulation development: the evolution pattern of the ratio of optical density to permittivity was representative of the culture state, and during the sporulation phase, a permittivity index could be build to measure the extend of spore liberation.

Functional anatomy of thalamus and basal ganglia

THALAMUS: The human thalamus is a nuclear complex located in the diencephalon and comprising of four parts (the hypothalamus, the epythalamus, the ventral thalamus, and the dorsal thalamus). The thalamus is a relay centre subserving both sensory and motor mechanisms. Thalamic nuclei (50-60 nuclei) project to one or a few well-defined cortical areas. Multiple cortical areas receive afferents from a single thalamic nucleus and send back information to different thalamic nuclei. The corticofugal projection provides positive feedback to the "correct" input, while at the same time suppressing irrelevant information. Topographical organisation of the thalamic afferents and efferents is contralateral, and the lateralisation of the thalamic functions affects both sensory and motoric aspects. Symptoms of lesions located in the thalamus are closely related to the function of the areas involved. An infarction or haemorrhage thalamic lesion can develop somatosensory disturbances and/or central pain in the opposite hemibody, analgesic or purely algesic thalamic syndrome characterised by contralateral anaesthesia (or hypaesthesia), contralateral weakness, ataxia and, often, persistent spontaneous pain. BASAL GANGLIA: Basal ganglia form a major centre in the complex extrapyramidal motor system, as opposed to the pyramidal motor system (corticobulbar and corticospinal pathways). Basal ganglia are involved in many neuronal pathways having emotional, motivational, associative and cognitive functions as well. The striatum (caudate nucleus, putamen and nucleus accumbens) receive inputs from all cortical areas and, throughout the thalamus, project principally to frontal lobe areas (prefrontal, premotor and supplementary motor areas) which are concerned with motor planning. These circuits: (i) have an important regulatory influence on cortex, providing information for both automatic and voluntary motor responses to the pyramidal system; (ii) play a role in predicting future events, reinforcing wanted behaviour and suppressing unwanted behaviour, and (iii) are involved in shifting attentional sets and in both high-order processes of movement initiation and spatial working memory. Basal ganglia-thalamo-cortical circuits maintain somatotopic organisation of movement-related neurons throughout the circuit. These circuits reveal functional subdivisions of the oculomotor, prefrontal and cingulate circuits, which play an important role in attention, learning and potentiating behaviour-guiding rules. Involvement of the basal ganglia is related to involuntary and stereotyped movements or paucity of movements without involvement of voluntary motor functions, as in Parkinson's disease, Wilson's disease, progressive supranuclear palsy or Huntington's disease. The symptoms differ with the location of the lesion. The commonest disturbances in basal ganglia lesions are abulia (apathy with loss of initiative and of spontaneous thought and emotional responses) and dystonia, which become manifest as behavioural and motor disturbances, respectively.

Glutamic residue 438 within the protease-sensitive subdomain of HIV-1 reverse transcriptase is critical for heterodimer processing in viral particles

The biological form of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) is a heterodimer consisting of two polypeptides, p66 and p51, which have identical N-termini. The p51 polypeptide is generated by action of viral protease cleaving the p66 polypeptide between residues Phe440 and Tyr441. Dimerization has been mostly studied using bacterially purified RT bearing amino acid changes in either subunit, but not in the context of HIV-1 particles. We introduced changes of conserved amino acid residues 430-438 into the protease-sensitive subdomain of the p66 subunit and analyzed the reverse transcriptase processing and function using purified variants and their corresponding HIV-1 recombinant clones. Our mutational analysis shows that the conserved Glu438 residue is critical for proper heterodimerization and function of virion-associated RT, but not of bacterially expressed RT. In contrast, the conserved Glu430, Glu432, and Pro433 residues are not important for dimerization of virion-associated RT. The network of interactions made by the Glu438 carboxyl group with neighboring residues is critical to protect the Phe440-Tyr441 from cleavage in the context of the p66/p51 heterodimer and may explain why the p66/p51 is not processed further to p51/p51.

Enzymatic digestive activity in Mytilus chilensis (Hupé 1854) in response to food regimes and past feeding history

Digestive enzyme activities (amylase, cellulase, laminarinase and protease) were analysed in mussels (Mytilus chilensis) from intertidal and subtidal habitats in Yaldad Bay, Chiloé, Chile. In order to analyse the effects of the past-feeding history (origin) and new nutritional conditions (habitat) on these enzymatic activities, a cross-over transplant was carried out and the analysis performed after a 7-day acclimation period. Crystalline styles showed higher carbohydrase and lower protease activities than digestive glands, with the highest differences recorded for subtidal mussels. Cellulase is the enzyme with the highest activity in both the digestive gland and crystalline style in all the experimental conditions. Intertidal mussels transplanted to a subtidal habitat showed enzyme resources significantly higher than in their original habitat. In the inverse case, mussels transferred from an original subtidal habitat to an intertidal one, a significant decrease in carbohydrase and protease activities was observed. The "past feeding history' is involved in the specific and total carbohydrase and protease activities, with a highly significant effect on amylase and cellulase activities in both the crystalline style and the digestive gland. Laminarinase activity can be interpreted considering the habitat (trophic regime), either individually or interacting with mussels' origin, in relation with the feeding periods. The results establish that in M. chilensis, an investment in enzyme resources is one of the mechanisms employed to optimise the acclimated response in terms of energy gains when variations in the food regime occur.

An integrated system to study multiply substituted human immunodeficiency virus type 1 reverse transcriptase

We describe a gene system allowing the facile production of multiply substituted reverse transcriptases (RTs), the enzymatic characterization of these purified RTs, and the study of these mutations in the defined genetic background of the macrophagetropic, non-laboratory-adapted human immunodeficiency virus type 1 (HIV-1) AD8 strain. Thirteen unique silent restriction sites were introduced in the pol gene encoding HIV-1 RT, allowing easy introduction of mutations. To simplify genetic manipulation and generate p66/p51 heterodimers in Escherichia coli, a gene construct of the viral protease alone was optimized for expression from a separate vector carrying a p15A origin of replication. Active-site titration experiments using pre-steady-state kinetics showed that our system yields a higher proportion of active enzyme than that obtained by alternate methods. To facilitate phenotype/genotype correlations, the modified RT gene was designed to be easily reintroduced into a recombinant proviral AD8 HIV-1 DNA. Infectious viruses made from this vector were undistinguishable from wild-type AD8 HIV-1, an isolate able to infect peripheral blood mononuclear cells and macrophages. Thus, the pol gene can tolerate many silent mutations in the polymerase domain without affecting the functionality of the HIV-1 genome. The system was validated biochemically and virologically using the V75T substitution associated with stavudine resistance.

The valine-to-threonine 75 substitution in human immunodeficiency virus type 1 reverse transcriptase and its relation with stavudine resistance

The amino acid change V75T in human immunodeficiency virus type 1 reverse transcriptase confers a low level of 2',3'-didehydro-2',3'-dideoxythymidine (stavudine, d4T) resistance in vivo and in vitro. Valine 75 is located at the basis of the fingers subdomain of reverse transcriptase between the template contact point and the nucleotide-binding pocket. V75T reverse transcriptase discriminates 3.6-fold d4T 5'-triphosphate relative to dTTP, as judged by pre-steady state kinetics of incorporation of a single nucleotide into DNA. In addition, V75T increases the DNA polymerization rate up to 5-fold by facilitating translocation along nucleic acid single-stranded templates. V75T also increases the reverse transcriptase-mediated repair of the d4TMP-terminated DNA by pyrophosphate but not by ATP. The V75T/Y146F double substitution partially suppressed both increases in rate of polymerization and pyrophosphorolysis, indicating that the hydroxyl group of Thr-75 interacts with that of Tyr-146. V75T recombinant virus was 3-4-fold d4T-resistant and 3-fold resistant to phosphonoformic acid relative to wild type, confirming that the pyrophosphate traffic is affected in V75T reverse transcriptase. Thus, in addition to nucleotide selectivity V75T defines a type of amino acid change conferring resistance to nucleoside analogues that links translocation rate to the traffic of pyrophosphate at the reverse transcriptase active site.

The role of LH in ovarian stimulation: exogenous LH: let's design the future

Historically, follicular stimulation protocols have included both FSH and LH in an attempt to mimic the physiology of normal human folliculogenesis. However, many recent gonadotrophin administration regimens have completely eliminated LH bioactivity. The importance and the amount of LH necessary for optimal follicular stimulation has been a topic of debate. Several recent studies have added to our understanding of the actions of androgens, oestrogens, gonadotrophins, and insulin on the follicle-oocyte unit, allowing a less speculative approach. Moreover, the availability of human gonadotrophins synthesized by recombinant DNA technology and gonadotrophin-releasing hormone (GnRH) antagonists, should soon permit a precise in-vivo assessment and re-evaluation of the historical 2-cell, two-gonadotrophin hypothesis. These pharmacological tools may also provide essential insights into the physiological roles of FSH and LH in human follicular development and oocyte maturation. The recombinant gonadotrophins give clinicians the unique opportunity to tailor ovarian stimulation regimens according to the patient's medical history, in an effort both to maximize oocyte yield and to improve oocyte quality.

Ammonium, bicarbonate and calcium effects on tomato plants grown under saline conditions

Tomato plants (70 days old) were grown in hydroponic culture into a greenhouse, where supply of inorganic carbon, ammonium and calcium to saline nutrient solution, was investigated in order to reduce the negative effect of salinity. After 70 days, an ameliorating effect upon the decrease in growth observed under salinity was only observed with the treatments NaCl+Ca(2+) and NaCl+HCO(3)(-)+NH(4)(+)+Ca(2+). A large reduction of hydraulic conductance (L(0)) and stomatal conductance (G(s)) was observed with all treatments, compared with the control. However, the reductions were less when NaCl and Ca(2+) were added together. Organic acids (mainly malic acid) in the xylem were decreased with all treatments except with NaCl+NH(4)(+) and with all single treatments added together (NaCl+HCO(3)(-)+NH(4)(+)+Ca(2+)). Amino acid concentrations in the xylem (mainly asparagine and glutamine) decreased when plants were treated with NaCl and NaCl+Ca(2+), but there was a large increase in the plants treated with NaCl+NH(4)(+) or with all treatments together. As HCO(3)(-) is an important source of carbon for NH(4)(+) assimilation, the increase in the concentration of amino acids and organic acids caused by the treatments that contained NH(4)(+), support the idea that fixation of dissolved inorganic carbon was occurring and that the products were transported via the xylem to the shoot. The ameliorating effect of Ca(2+) on root hydraulic conductivity plus the increase of NH(4)(+) incorporation into the amino acid synthesis pathway possibly due to dissolved inorganic carbon fixation, could reduce the negative effect of salinity on tomato plants.

Frequent chromosome 8q gains in human small cell lung carcinoma detected by arbitrarily primed-PCR genomic fingerprinting

The arbitrarily primed-polymerase chain reaction (AP-PCR) genomic fingerprinting method was applied to detect chromosomal numerical imbalances in 13 small cell lung carcinomas (SCLC). Increases and decreases in the intensity of the AP-PCR bands from several chromosomes, representing gains of chromosomes 1, 7, 16, and X, and losses of chromosomes 2, 10, and 22, were recurrent events in independent tumors. In addition, the most common alterations detected were increases in signal intensity of three AP-PCR bands derived from genomic sequences on chromosome 8q (eight of 13 tumors: 62%). To define whether the 8q gains observed in the AP-PCR analysis include the C-MYC gene at chromosome 8q24 or not, we performed targeted AP-PCR analysis of the C-MYC gene. The C-MYC gene was amplified in five of the eight tumors with gains of 8q, but in none of the remaining five tumors in which 8q gains were not detected. These results indicate that chromosome 8q gain occurs frequently in SCLC and gained regions often, but do not always, include the C-MYC gene. Moderate increases in copy number of the C-MYC gene and additional gene(s) in the 8q region appear to be under positive selection during SCLC progression.

Interactive effects of diet and temperature on the scope for growth of the scallop Argopecten purpuratus during reproductive conditioning

Mature individuals of Argopecten purpuratus from suspended culture in Tongoy Bay, northern Chile were conditioned at two temperatures (16 and 20 degrees C) and three different diets (mixture of pure microalgae, microalgae supplemented with lipids and microalgae supplemented with carbohydrates). The food, equivalent to 3% daily of the animal dry weight was supplied continuously by a peristaltic pump. The rates of different physiological processes were measured on 18 scallops (three replicates per temperature/diet combination) during the third week of conditioning. Nine scallops came from the group conditioned at 16 degrees C and other nine from the group conditioned at 20 degrees C (each scallop from a different tank). As in the conditioning experiment, physiological measurements were made in controlled temperature rooms using the same experimental diets. Argopecten purpuratus did not show significant differences in clearance rate between 16 and 20 degrees C when fed with pure microalgae and microalgae+lipids, showing a well known capability of bivalves to acclimate their physiological rates within a certain range of temperature. On the other hand a clear effect of the composition of the diet on the clearance rate was observed. When microalgae were supplemented with a lipid emulsion, clearance rate was highly stimulated, showing values significantly higher in comparison with either pure microalgae, or a mixed diet of microalgae+carbohydrate. These highest feeding rates can be related with the presence of essential fatty acids in the diet, which are considered as very important compounds during the gametogenesis of invertebrates as well as during the development of ova into normal larvae. Thus A. purpuratus can actively regulate clearance rate and does not simply switch between feeding and non-feeding states. The data also suggest the presence of chemical receptors at the level of the gills and/or labial palps, which seem able to detect specific nutritive compounds present in the diet. Absorption efficiency was independent of temperature and was higher with pure microalgae and with microalgae+lipids. The lowest efficiencies were recorded with the diet supplemented with carbohydrates. The energy expended in oxygen uptake and ammonia excretion was very similar in the different experimental diets and temperatures. Scope for growth in A. purpuratus appears mainly affected by the diet and not by temperature. While the lower SFG seems to be associated with diets composed of pure microalgae and microalgae+carbohydrates, the highest values being found for a diet rich in lipids. The data were in agreement with the reproductive conditioning of A. purpuratus, where the highest percentage of ripe scallops occurred in individuals fed with a diet of microalgae supplemented with lipids at both temperatures. Similarly the highest larval survival rate was obtained from gametes released by scallops conditioned with the diet containing lipids.

[Evaluation of the Glucocard Memory 2 analyzer for measuring glucose concentration in capillary blood]

OBJECTIVE

To evaluate the analytical reliability and accuracy as well as the practicability of the Glucocard Memory 2 glucose meter, intended to the control of the diabetic patient.

DESIGN

Descriptive, crossover study. To validate an analytical instrument according to guidelines of the Spanish Society of Clinical Biochemistry and Molecular Pathology.

SETTING

Primary health care, urban setting.

PARTICIPANTS

Ninety-three blood samples from diabetic patients were used. These samples were selected by a consecutive sampling of the tubes received in the laboratory for the diabetes follow-up protocol.

MEASUREMENTS AND MAIN RESULTS

Repeatability of the system was studied analysing the within-run precision at four concentrations of glucose. We obtained coefficients of variation between 2.12% (at 410 mg/dl of glucose) and 4.17% (at 37.2 mg/dl). The linearity study allowed to check experimentally the linear response of the instrument between 27 and 485 mg/dl. The accuracy was evaluated comparing the Glucocard results with the routine procedure of our laboratory (Hitachi 747, GOD-PAP) and calculating the regression parameters with the Passing and Bablok method (y = 1.01 x -2.34) and the intraclass correlation (99%). To evaluate the clinical significance of possible deviations related with the reference laboratory method the "error Grid" analysis was used. This analysis showed that 100% of Glucocard Memory 2 results fell into the clinical accuracy zone. Practicability study showed that the instrument is very simple to use.

CONCLUSIONS

Glucocard Memory 2 is a glucose meter intended to the measurement of glucose both on capillary and venous blood that, besides its extreme simplicity of use, shows very good analytical features.

The use of arbitrarily primed polymerase chain reaction in cancer research

There is a great need for techniques that detect the genome alterations present in cancer cells. Here, we present a review of the arbitrarily primed polymerase chain reaction (AP-PCR), a genomic mutation detection method with some unique advantages: (i) It can detect most types of mutations that usually occur in tumors (except point mutations). (ii) It is especially useful to detect moderate gains in DNA, which most methods currently in use cannot detect. (iii) It allows detection and cloning of alterations in a single experiment. (iv) It is inexpensive and does not require special equipment. We discuss some characteristics of this method and review some of its achievements in cancer research.

The HIV-1 Vpr co-activator induces a conformational change in TFIIB

Vpr is a HIV-1 virion-associated protein which plays a role in viral replication and in transcription and cell proliferation. We have previously reported that Vpr stimulates transcription of genes lacking a common DNA target sequence likely through its ability to interact with TFIIB. However, the molecular mechanism of the Vpr-mediated transcription remains to be precisely defined. In this in vitro study, we show that the binding site of Vpr in TFIIB overlaps the domain of TFIIB which is engaged in the intramolecular bridge between the N- and C-terminus of TFIIB, highly suggesting that binding of Vpr may induce a change in the conformation of TFIIB. Indeed, with a partial proteolysis assay using V8 protease, we demonstrate that Vpr has the ability to change the conformation of TFIIB. We investigated in this partial proteolysis assay a series of Vpr-mutated proteins previously defined for their transactivation properties. Our data show a correlation between the ability of Vpr-mutated proteins to stimulate transcription and their ability to induce a conformational change in TFIIB, indicating a functional relevance of the Vpr-TFIIB interaction.

A functional chimera of mammalian guanylyl and adenylyl cyclases

Adenylyl and guanylyl cyclases synthesize second messenger molecules by intramolecular esterification of purine nucleotides, i.e., cAMP from ATP and cGMP from GTP, respectively. Despite their sequence homology, both families of mammalian cyclases show remarkably different regulatory patterns. In an attempt to define the functional domains in adenylyl cyclase responsible for their isotypic-common activation by Galphas or forskolin, dimeric chimeras were constructed from soluble guanylyl cyclase alpha1 subunit and the C-terminal halves of adenylyl cyclases type I, II, or V. The cyclase-hybrid generated cAMP and was inhibited by P-site ligands. The data establish structural equivalence and the ability of functional complement at the catalytic sites in both cyclases. Detailed enzymatic characterization of the chimeric cyclase revealed a crucial role of the N-terminal adenylyl cyclase half for stimulatory actions, and a major importance of the C-terminal part for nucleotide specificity.

DNA repair enzyme uracil DNA glycosylase is specifically incorporated into human immunodeficiency virus type 1 viral particles through a Vpr-independent mechanism

The Vpr protein, encoded by the human immunodeficiency virus type 1 (HIV-1) genome, is one of the nonstructural proteins packaged in large amounts into viral particles. We have previously reported that Vpr associates with the DNA repair enzyme uracil DNA glycosylase (UDG). In this study, we extended these observations by investigating whether UDG is incorporated into virions and whether this incorporation requires the presence of Vpr. Our results, with highly purified viruses, show that UDG is efficiently incorporated either into wild-type virions or into Vpr-deficient HIV-1 virions, indicating that Vpr is not involved in UDG packaging. Using an in vitro protein-protein binding assay, we reveal a direct interaction between the precursor form of UDG and the viral integrase (IN). Finally, we demonstrate that IN-defective viruses fail to incorporate UDG, indicating that IN is required for packaging of UDG into virions.

The use of arbitrarily primed polymerase chain reaction in cancer research

There is a great need for techniques that detect the genome alterations present in cancer cells. Here, we present a review of the arbitrarily primed polymerase chain reaction (AP-PCR), a genomic mutation detection method with some unique advantages: (i) It can detect most types of mutations that usually occur in tumors (except point mutations). (ii) It is especially useful to detect moderate gains in DNA, which most methods currently in use cannot detect. (iii) It allows detection and cloning of alterations in a single experiment. (iv) It is inexpensive and does not require special equipment. We discuss some characteristics of this method and review some of its achievements in cancer research.

Ecto-5'-nucleotidase from a human colon adenocarcinoma cell line. Correlation between enzyme activity and levels in intact cells

Differences on 5'-nucleotidase activity in intact Rugli and BCS-TC2 cells (rat glioblastoma and human colon adenocarcinoma cell lines, respectively) are not due to differences in the characteristics of the ectoenzyme. A membrane-bound 5'-nucleotidase from BCS-TC2 cells has been purified to homogeneity with a high specific activity (130 U/mg), yielding a single 72-kDa band on SDS-PAGE. It is a metalloenzyme and, after inhibition by EDTA, its activity can be partially restored by divalent cations. The hydrolysis of the nucleosides 5'-monophosphate used as substrate follows Michaelis-Menten kinetics; ADP and concanavalin A are competitive and non-competitive inhibitors of the AMPase activity, respectively. This ecto-5'-nucleotidase is a high-mannose glycoprotein; deglycosylation converts the 72-kDa into a 59-kDa protein with a concomitant activity loss. The enzyme purified from BCS-TC2 cells shows similar characteristics from that previously isolated from Rugli cells; differences between them are mainly due to glycosylation. Polyclonal antibodies against 5'-nucleotidase from BCS-TC2 cells also show cross-reactivity with the enzyme from Rugli cells. When the ectoenzyme activity is measured in cells in culture, Rugli cells present a higher activity than BCS-TC2 cells however, they express very low amounts of ecto-5'-nucleotidase. Our results also show a reduction in protein level and enzyme activity associated with a decrease in the differentiation degree and an increase in tumorigenicity of human colon adenocarcinoma BCS-TC2 sublines.

A role for human immunodeficiency virus type 1 Vpr during infection of peripheral blood mononuclear cells

Studies analysing human immunodeficiency virus type 1 replication in primary cells have demonstrated that Vpr, although dispensable, plays a role along with the matrix (MA) protein in allowing nuclear localization of viral preintegration complexes in non-dividing monocyte-derived macrophages (MDMs). In the current study, experimental infection conditions to analyse the role of Vpr, independently of MA, during infection of PHA/IL-2-stimulated peripheral blood mononuclear cells (PBMC) were designed. It was shown that the absence of Vpr results in a subtle effect on virus production in long-term infection. PCR analysis of the steps of virus retrotranscription during a single cycle of replication in stimulated PBMC revealed that the absence of Vpr alone correlates with an impairment in the nuclear localization of viral DNA. Our data indicate that Vpr is involved in the virus life-cycle during infection of dividing PBMC, presumably as it is during infection of MDMs.

Differentiation of BCS-TC2 human colon adenocarcinoma cells by sodium butyrate: increase in 5'-nucleotidase activity

We have analysed the major effects of sodium butyrate on the morphology, protein content and induction of epithelial differentiation markers in human colon adenocarcinoma BCS-TC2 cells. Sodium butyrate alters the cell morphology, inducing a larger cellular size, flattening and vacuolization. The protein content per cell increases, whereas the proliferation rate is reduced. Moreover, cell death by apoptosis is also observed. Butyrate-treated cells show higher levels of alkaline phosphatase activity and carcinoembryonic antigen, suggesting that this agent induces the in vitro differentiation of BCS-TC2 cells. These effects are reversible and time and dose dependent. In addition, we have observed that the ectoenzyme 5'-nucleotidase activity also increases during this treatment, suggesting that it could be considered as a new differentiation marker for this type of carcinoma cells. These results contribute to the understanding of the action of sodium butyrate as a potential cancer chemotherapeutic agent.

Endocarditis caused by nonhemolytic group B streptococcus

We report a case of bacterial endocarditis caused by nonhemolytic group B streptococcus (GBS) in a 67-year-old man with no predisposing risk factors. Nonhemolytic GBS strains rarely cause illness and are usually detected in perinatal infections. We believe this to be the first reported case of endocarditis caused by a nonhemolytic strain of GBS.

The human immunodeficiency virus type 1 Vpr transactivator: cooperation with promoter-bound activator domains and binding to TFIIB

Since the first report documenting that HIV-1 Vpr was involved in the stimulation of transactivation of several unrelated promoters, little additional information has been reported. By using transient transfection experiments, we confirmed and extended these previously reported data. Further in vivo experiments showed that Vpr can co-operatively stimulate transactivation activity of a minimal promoter containing one GAL4 DNA-binding site, when it is co-expressed with different heterologous activator domains fused to GAL4 DNA-binding domain. Thus, Vpr could transactivate in concert with an activator domain, but has no effect on the transactivation of a minimal promoter in the absence of activator protein. To investigate whether Vpr can interact with components of the basal transcriptional machinery, in vitro protein-protein binding assays were performed using either translated, radiolabeled Vpr or TFIIB proteins and glutathione S-transferase Vpr or TFIIB chimeric proteins. We demonstrated that the portion of Vpr ranging from amino acids 15 to 77 interacts specifically with the basal transcription factor TFIIB. Also, our data indicated that the N-terminal domain of TFIIB is required for the interaction.

Chromosomal assignment of human DNA fingerprint sequences by simultaneous hybridization to arbitrarily primed PCR products from human/rodent monochromosome cell hybrids

We have developed a technique for the simultaneous chromosomal assignment of multiple human DNA sequences from DNA fingerprints obtained by the arbitrarily primed polymerase chain reaction (AP-PCR). Radioactively labeled human AP-PCR products are hybridized to DNA fingerprints generated with the same arbitrary primer from human/rodent monochromosome cell hybrids after electroblotting to a nylon membrane. Human-specific hybridization bands in the human/rodent fingerprints unambiguously determine their chromosome of origin. We named this method simultaneous hybridization of arbitrarily primed PCR DNA fingerprinting products (SHARP). Using this approach, we determined the chromosomal origins of most major bands of human AP-PCR fingerprints obtained with two arbitrary primers. Altogether, the chromosomal localization of near 50 DNA fragments, comprehensive of all human chromosomes except chromosomes 21 and Y, was achieved in this simple manner. Chromosome assignment of fingerprint bands is essential for molecular karyotyping of cancer by AP-PCR DNA fingerprinting. The SHARP method provides a convenient and powerful tool for this purpose.

Human immunodeficiency virus type 1 Vpr protein binds to the uracil DNA glycosylase DNA repair enzyme

The role of the accessory gene product Vpr during human immunodeficiency virus type 1 infection remains unclear. We have used the yeast two-hybrid system to identify cellular proteins that interact with Vpr and could be involved in its function. A cDNA clone which encodes the human uracil DNA glycosylase (UNG), a DNA repair enzyme involved in removal of uracil in DNA, has been isolated. Interaction between Vpr and UNG has been demonstrated by in vitro protein-protein binding assays using translated, radiolabeled Vpr and UNG recombinant proteins expressed as a glutathione S-transferase fusion protein. Conversely, purified UNG has been demonstrated to interact with Vpr recombinant protein expressed as a glutathione S-transferase fusion protein. Coimmunoprecipitation experiments confirmed that Vpr and UNG are associated within cells expressing Vpr. By using a panel of C- and N-terminally deleted Vpr mutants, we have determined that the core protein of Vpr, spanning amino acids 15 to 77, is involved in the interaction with UNG. We also demonstrate by in vitro experiments that the enzymatic activity of UNG is retained upon interaction with Vpr.

Elements controlling the expression and induction of the skin hyperproliferation-associated keratin K6

The suprabasal keratin 6 (K6) is remarkable among the keratins as, in addition to being constitutively expressed in different stratified epithelia, it is induced in epidermis under hyperproliferative conditions, such as benign or malignant tumors, psoriasis, and wound healing. In addition, this keratin is also induced in skin treated with 12-O-tetradecanoylphorbol-13-acetate or retinoic acid (RA). These characteristics make the study of K6 regulatory elements an especially interesting issue, in particular because these elements could be useful in designing gene constructs for the therapy of skin diseases. We have analyzed by mobility shift and footprinting experiments the cell type-specific enhancer of the bovine K6 beta gene (Blessing, M., Jorcano, J. L., and Franke, W. W. (1989) EMBO J. 8, 117-126) and have identified an AP-2-like element, two AP-1 elements (one of them composite), and a retinoic acid-responsive element (RARE). Mutagenesis experiments and cotransfections with retinoic acid receptors show that the RARE mediates enhancer activation by RA. Chloramphenicol acetyltransferase assays show that under normal culture conditions, the AP-1 element retains most of the enhancer transcriptional activity, while the RARE and AP-2 are weakly active. However, following RA treatment, the AP-1 element is repressed and the RARE is activated, resulting in an overall stimulation of the enhancer by RA in the BMGE+H cells used in our study. These results explain in part the complex and sometimes contradictory response of keratin 6 to hyperproliferative stimuli.