Seasonal fluctuations of tissue mercury contents in the European shore crab Carcinus maenas from low and high contamination areas (Ria de Aveiro, Portugal)

The main objective was to study the seasonal variation of mercury concentrations in different tissues (muscle, hepatopancreas and gills) of Carcinus maenas from low and high Hg contaminated areas, a valuable resource in temperate estuaries and a possible pathway for human uptake. Individuals of two size classes (around 35 and 55 mm cephalothorax wide) were captured monthly between March 1999 and May 2000 in two areas of Ria de Aveiro: in the main navigation channel that connects the lagoon to the sea, and in the inner lagoon area heavily contaminated by mercury (maximum Hg in sediments of 5.4 microg g(-1)). Pronounced decreases in salinity and temperature and reduced food availability in winter seemed to be the responsible for the decline of the crab condition index (0.75-0.45) in larger individuals. Muscle and hepatopancreas exhibited higher mercury concentrations than gills, with concentrations in the contaminated site ranging from 0.03 to 0.63 microg g(-1) and 0.02 to 0.34 microg g(-1), respectively. Linear regressions between muscle and hepatopancreas (r=0.94, p<0.001) and muscle and gills (r=0.97, p<0.001) suggested a rapid redistribution of mercury inside the organism. During winter, a rapid elimination of mercury was found in the three analysed tissues followed by uptake. Larger crabs presented elimination rates from 18 to 34 ng g(-1) per week, while the smaller crabs showed lower elimination rates (10-24 ng g(-1) per week). The uptake was similar in both size classes (11-15 ng g(-1) and 8.1-15 ng g(-1) per week, respectively for large and small crabs). Our results suggest that C. maenas harvested in the contaminated areas must be considered with caution, since Hg concentrations were found to exceed the threshold concentration allowed for human consumption (0.5 microg g(-1)).

Parkinson's disease and primate research: past, present, and future

Scientific research involving non-human primates has contributed towards many advances in medicine and surgery. This review discusses its role in the progress made towards our understanding of Parkinson's disease and its treatment. Established medical treatments like dopamine agonists continue to need primate models to assess their efficacy, safety, and mechanism of action. The recently developed treatment of deep brain stimulation of the subthalamic nucleus required validation in primates before entering the clinic. Controversies surrounding future treatments such as gene therapy show the need for properly evaluated preclinical research using appropriate animal models before progression to clinical trials. Research on primates has played--and continues to play--a crucial part in deepening our understanding of Parkinson's disease, improving current therapies, and developing new treatments that are both safe and effective. In animal research, the "three Rs" of humane technique--reduction, refinement, and replacement--should be adhered to.

Use of survival analysis as a tool for the genetic improvement of age at first conception in Nellore cattle

Restricted breeding seasons in beef cattle lead to censoring of reproductive data. In this paper, age at first conception (AFC) of Nellore females exposed to the sires for the first time between 11 and 16 months of age, was studied aiming to verify the possibility of genetically advance sexual precocity using a survival model. The final data set contained 6699 records of AFC in days. Records of females that did not calve in the next year following exposure to the sire were considered censored (77.5% of total). The model used was a Weibull mixed survival model including effects of contemporary groups, period (fixed) and animal (random). The effect of the contemporary groups on AFC was important (p < 0.01). Heritabilities were 0.51 and 0.76 in logarithmic and original scales respectively. Results indicate that it is possible to genetically advance sexual precocity, using the outcome of survival analysis of AFC as selection criterion. They also suggest that improvements of the environment could advance sexual precocity too, thus an adequate pregnancy rate for farmers could quickly be achieved.

Mercury distribution in Douro estuary (Portugal)

Determinations of dissolved reactive and total dissolved mercury, particulate and sedimentary mercury, dissolved organic carbon (DOC), particulate organic carbon (POC) and suspended particulate matter (SPM) have been made in the estuary of river Douro, in northern Portugal. The estuary was stratified by salinity along most of its length, it had low concentrations of SPM, typically <20 mg dm(-3), and concentrations of DOC in the range <1.0-1.8 mg dm(-3). The surface waters had a maximum dissolved concentration of reactive mercury of about 10 ng dm(-3), whereas for the more saline bottom waters it was about 65 ng dm(-3). The surface waters had maximum concentrations of total suspended particulate mercury of approximately 7 microg g(-1) and the bottom waters were always <1 microg g(-1). Concentrations of mercury in sediments was low and in the range from 0.06 to 0.18 microg g(-1). The transport of mercury in surface waters was mainly associated with organic-rich particulate matter, while in bottom waters the dissolved phase transport of mercury is more important. Lower particulate organic matter, formation of chlorocomplexes in more saline waters and eventually the presence of colloids appear to explain the difference of mercury partitioning in Douro estuarine waters.

Using biosensors to detect the release of serotonin from taste buds during taste stimulation

CHO cells transfected with high-affinity 5HT receptors were used to detect and identify the release of serotonin from taste buds. Taste cells release 5HT when depolarized or when stimulated with bitter, sweet, or sour tastants. Sour- and depolarization-evoked release of 5HT from taste buds is triggered by Ca2+ influx from the extracellular fluid. In contrast, bitter- and sweet-evoked release of 5HT is triggered by Ca2+ derived from intracellular stores.

Overlapping stent-supported coil embolization of wide-neck basilar tip aneurysm: technical case reports

We report two cases in which wide-neck basilar aneurysms were treated with overlapping stent-supported coil embolization. This overlapping technique ensures complete stent interface with the aneurysm neck and likely improves long-term outcomes. We demonstrated the feasibility of this novel technique and suggest its application for other bifurcation aneurysms requiring stent-supported coil embolization.

Parâmetros genéticos para escore de umbigo e características de produção em bovinos da raça Nelore

Utilizaram-se 11.310 medidas de escore visual da característica umbigo, medida aos 18 meses em bovinos, para estimar os componentes de variância, a herdabilidade e as correlações genéticas entre escore do umbigo e peso à desmama (PD) e ganho de peso da desmama ao sobreano (GP345), utilizando-se modelo animal bi-característica Os escores de umbigo (EU) variaram de 1 (mais pendulosos) a 5 (mais curtos). Os valores de herdabilidade foram 0,31 (PD), 0,14 (GP345) e 0,29 (EU), e as correlações genéticas foram -0,05 (EU×PD) e 0,14 (EU×GP345). A correlação entre avaliação do umbigo de machos e fêmeas foi de 0,80. Conclui-se que a característica umbigo é passível de seleção e que ela não compromete a seleção para melhores PD e GP345.

Risk factors for failure of Helicobacter pylori therapy--results of an individual data analysis of 2751 patients

AIM

To study risk factors for failure of Helicobacter pylori eradication treatment.

METHODS

Individual data from 2751 patients included in 11 multicentre clinical trials carried out in France and using a triple therapy, were gathered in a unique database. The 27 treatment regimens were regrouped into four categories.

RESULTS

The global failure rate was 25.8% [95% CI: 24-27]. There was a difference in failure rate between duodenal ulcer patients and non-ulcer dyspeptic patients, 21.9% and 33.7%, respectively (P < 10(-6)). In a random-effect model, the risk factors identified for eradication failure in duodenal ulcer patients (n = 1400) were: to be a smoker, and to have received the group 4 treatment, while to receive a 10 day treatment vs. 7 days protected from failure. In non-ulcer dyspeptic patients (n = 913), the group 2 treatment was associated with failure. In both groups, age over 60 was associated with successful H. pylori eradication. There were less strains resistant to clarithromycin in duodenal ulcer patients than in non-ulcer dyspeptic patients. Clarithromycin resistance predicted failure almost perfectly.

CONCLUSION

Duodenal ulcer and non-ulcer dyspeptic patients should be managed differently in medical practice and considered independently in eradication trials.

Specific abnormalities in serotonin release in the prefrontal cortex of isolation-reared rats measured during behavioural performance of a task assessing visuospatial attention and impulsivity

RATIONALE

Rats reared in social isolation exhibit hyperactivity and specific attentional disturbances in later adult life. These behavioural abnormalities may be relevant to impulsivity and other neuropsychiatric syndromes such as attention-deficit hyperactivity disorder and schizophrenia where disturbances in circuitry involving the prefrontal cortex have been identified.

OBJECTIVE

To establish whether isolation-reared rats show a differential susceptibility to cognitive processes that depend on the prefrontal cortex and its monoaminergic innervation.

METHODS

Rats were reared in isolation from postnatal day 28 or in social groups of four and trained on the five-choice serial reaction time task, which assesses spatially divided visual attention. Following a range of manipulations designed to tax visual attention and response control, in vivo microdialysis was used in conjunction with behavioural testing to assess dopamine (DA) and serotonin (5-HT) release in the prefrontal cortex, either under baseline conditions prior to task initiation, or during task performance. Subjects were challenged with amphetamine (0.125 mg/kg intravenously) every 15 min, commencing 15 min after the start of the task.

RESULTS

Apart from being consistently slower to collect food rewards and showing more perseverative responses to an auditory distractor, isolates were unimpaired on accuracy, impulsivity and correct latency measures on the five-choice task. Basal levels of DA and 5-HT in the prefrontal cortex were also unaffected by isolation rearing. Amphetamine increased the speed of responding in control and isolation-reared animals and increased premature (impulsive) responding, but only in socially-reared animals. Cortical DA release increased to a similar extent in both groups following amphetamine challenge. By contrast, 5-HT release was attenuated in isolates under these conditions.

CONCLUSIONS

These findings highlight a rather specific deficit in 5-HT release in the prefrontal cortex of isolation-reared rats, although this appears not to affect visual attentional function. Rather, these data may be relevant to reduced impulsiveness of isolation-reared rats on the five-choice task. These findings are important in the context of animal models of attentional disturbances in schizophrenia.

[Central diabetes insipidus: a case report]

INTRODUCTION

Diabetes insipidus (DI) is a syndrome characterised by polyuria which is almost always associated with polydipsia. The most frequent cause is central DI, which is the result of an inadequate secretion of the diuretic hormone, and diagnosis involves differentiating it from other causes of polyuria and polydipsia.

CASE REPORT

The authors report the clinical case of a previously healthy 4 year old girl, who, in December 1998, was found to have intense polydipsia accompanied by polyuria. Behavioural treatment was begun as an answer to what was thought to be psychogenic polydipsia, although results were unsatisfactory and the patient was brought to the Paediatric Nephrology Service at Hospital Maria Pia in June 1999.

CONCLUSION

A clinical study, which included the water restriction test and concentration tests with desmopressin, enabled us to diagnose central DI. In spite of the results from a cranial NMR scan being normal, follow up time is still too short to classify the aetiology as idiopathic. The girl is asymptomatic under treatment with intranasal desmopressin. The favourable evolution in this case highlights the need to act in a thorough manner in the study of situations involving polyuria/polydipsia.

Cytotoxic effects of metal complexes of biogenic polyamines. I. Platinum(II) spermidine compounds: prediction of their antitumour activity

Cytotoxicity and cell growth inhibition studies were performed for three distinct polynuclear platinum(II) complexes of spermidine, which showed to have significant cytotoxic and antiproliferative properties on the HeLa cancer cell line. The chemical environment of the metal centres in the drugs, as well as the coordination pattern of the ligand, were found to be strongly determinant of their cytotoxic ability. In the light of the results gathered, the most effective anticancer compound among the ones tested (IC50=5 microM) was found to be the one displaying three difunctional (PtCl2N2) moieties ((PtCl2)3(spd)2). Both the cytotoxic activity and the antiproliferative properties of the complexes studied showed to be irreversible for all the concentrations tested.

Análise genética de algumas características reprodutivas e suas relações com o desempenho ponderal na raça Nelore

Com o objetivo de estudar as características idade ao primeiro parto de fêmeas expostas pela primeira vez ao touro em torno de 14 meses de idade (IPP14) ou em torno de 26 meses (IPP26), dias para o parto (DPP), duração da gestação (DG) e perímetro escrotal (PE) e suas relações com as características de desempenho ponderal peso ao nascer (PESNAS), peso à desmama (PESDES), peso ao sobreano (PESSOB) e ganho de peso da desmama ao sobreano (GP345) na raça Nelore, foram analisados conjuntos de dados que variaram de 6.030 a 94.637 observações, de acordo com a característica. As análises foram processadas utilizando-se modelos animais bi-característica. Os coeficientes de herdabilidade obtidos para características reprodutivas foram: 0,18 (IPP14); 0,02 (IPP26); 0,06 (DPP); 0,26 (DG); e 0,46 (PE). As correlações entre PE e características de desempenho ponderal indicaram que os pesos não são antagônicos ao perímetro escrotal. Embora as correlações genéticas entre PESDES e características reprodutivas das fêmeas tenham sido de baixas a moderadas no sentido desfavorável, não se recomenda aumento no tamanho adulto dos animais nesses rebanhos para evitar o risco de baixo desempenho reprodutivo. As características PESSOB e GP345 não são antagônicas à precocidade sexual e à fertilidade das fêmeas, exceto à duração da gestação.

Leukotriene receptor antagonists (Montelukast) in the treatment of asthma crisis: preliminary results of a double-blind placebo controlled randomized study

OBJECTIVE

Evaluate the efficacy of oral Montelukast 10 mg as an add-on therapy to the usual emergency therapy of an asthma crisis in an emergency room (ER).

POPULATION

Twenty adults that sought medical attention in the ER of our Hospital and in whom, on admission, it appeared unnecessary to give systemic steroids.

METHODS

All patients received the usual therapy of the asthma crisis. Simultaneously it was randomly administered a capsule containing 10 mg Montelukast or placebo, in a double-blind protocol. In both groups we evaluated the evolution of Peak-Flow values, the duration of stay in the ER as well as the need for additional therapy with systemic aminophylline or steroids, representing an insufficient response to the initial treatment. Student's T test was used to evaluate the statistical differences between these two groups.

RESULTS

Both the Montelukast (MK) and Placebo (PL) groups were comparable regarding age and sex distribution, Peak-Flow values and Arterial O2 values on admission. During therapy, MK group had a shorter duration of ER stay (MK = 2.5 h; PL = 2.9 h) and a better evolution of Peak-Flow values (medium increase of 55% from baseline versus 44% in PL group). However these differences did not reach statistical significance. In the MK group one patient needed systemic steroids and 4 received systemic aminophylline while in the PL group 4 patients received systemic steroids and 8 aminophylline. This difference was significant (p = 0.03). We did not observe any significant side effects during therapy.

CONCLUSIONS

Despite a small trend favourable to Montelukast we did not observe significant differences between groups regarding duration of stay or Peak-Flow evolution during therapy in ER, most probably due to the small sample size. However patients in the MK group needed significantly less systemic therapy with aminophylline or steroids. These data, in view of the very good safety profile of Montelukast, allow us to conclude that this is a useful additional therapy, which should be considered in the ER treatment of the asthma crisis.

Microwave treatment of biological samples for methylmercury determination by high performance liquid chromatography-cold vapour atomic fluorescence spectrometry

A simple and rapid microwave-assisted alkaline digestion procedure was developed in combination with high performance liquid chromatography-ultraviolet post-column oxidation-cold vapour atomic fluorescence spectrometric detection for methylmercury determination in biological tissues. Since the stability of methylmercury in methanolic potassium hydroxide solution under microwave irradiation was verified, the microwave-assisted extraction procedure was optimized in terms of quantitative recovery of methylmercury and minimum time required. The alkaline extracts were subjected to clean-up steps with dichloromethane and hydrochloric acid in order to reduce matrix interferences in methylmercury determination. The effects of matrix interferences were checked by comparison of the slopes corresponding to calibration and standard addition curves. The accuracy of the method was evaluated by the analysis of two biological certified reference materials, NRC TORT-2 and BCR 463. The results obtained by the proposed method were in good agreement with the certified values of methylmercury concentration in both materials. The detection limit was 10 microg kg(-1) and the relative standard deviation was < 8% for methylmercury concentrations ranging from 0.15 to 3.0 mg kg(-1).

Does alkalinization of 0.75% ropivacaine promote a lumbar peridural block of higher quality?

BACKGROUND AND OBJECTIVES

We did not find clinical studies of the alkalization of ropivacaine in the literature. The objectives of this study were: (1) to determine the quantity of sodium bicarbonate (NaHCO(3)), which alkalinizes 0.75% ropivacaine (with and without adrenaline); (2) to verify the physico-chemical alterations arising from this alkalization; and (3) to determine whether alkalinized ropivacaine produces a higher-quality epidural block measured via sensory-motor onset, block spread and anesthesia duration.

METHODS

It was determined in the laboratory that 0.012 and 0.015 mEq of NaHCO(3), respectively, alkalinized 10 mL of the 0.75% ropivacaine solutions without and with adrenaline (1:200,000). In the second phase, the study was random and double-blind and involved 60 patients divided into 3 groups of 20 (G1, G2, and G3). Via epidural lumbar blocks, these groups received, respectively, 10 mL of 0.75% ropivacaine plus 0.5 mL of 0.9% NaCl (solution A), 10 mL of 0.75% ropivacaine plus 0.0012 mEq of NaHCO(3) (solution B), and 10 mL of 0.75% ropivacaine (with adrenaline) plus 0.015 mEq of NaHCO(3) (solution C). The pH, PCO(2) (partial CO(2) pressure), and the nonionized fractions of the 0.75% ropivacaine solutions were compared before and after the addition of 0.9% NaCl or NaHCO(3) or adrenaline plus NaHCO(3). The motor and sensory onsets, block spread, and the duration of the block were evaluated.

RESULTS

The values of the pH, PCO(2), and nonionized fractions increased significantly in solutions B and C in relation to solution A. No differences among the groups were observed in relation to block spread and sensory-motor onset. The duration of the sensory blocks was significantly greater in the patients in groups G2 and G3.

CONCLUSION

This study indicates that the quantity of NaHCO(3) needed to alkalize 10 mL of 0.75% ropivacaine at room temperature is 0.012 mEq. When the solution contains adrenaline 1:200,000 (mg.mL(-1)), up to 0.015 mEq of NaHCO(3) may be added. The alkalization of the 0.75% ropivacaine solution did not cause a reduction of sensory-motor onset, but did provide a significant increase in the duration of the epidural block with no significant differences between the solutions with and without adrenaline.

Cyanobacteria diversity and toxicity in a wastewater treatment plant (Portugal)

Cyanobacteria are common in eutrophic natural waters. Being favoured by warm, stable and nutrient-enriched waters they may constitute an important part of the phytoplankton community in Wastewater Treatment Plants (WWTP). The phytoplankton communities of two ponds (facultative and maturation) of the WWTP of Esmoriz (North Portugal) were studied, with particular importance given to cyanobacteria. Mouse bioassays were performed with cyanobacteria samples during some of the blooms and ELISA assays specific for hepatotoxic microcystins were carried out. During the study period (January-July 1999) cyanobacteria were frequently dominant in the ponds ranging from 15.2 to 99.8% of the total phytoplankton density. The main species were Planktothrix mougeotii, Microcystis aeruginosa and Pseudanabaena mucicola. Mouse bioassays were performed during Oscillatoria bloom period but the results were negative, in spite of the high cyanobacteria biomass. ELISA assays were performed for both ponds but only in the maturation pond positive values were found. Microcystin concentrations (as MCYST-LR equivalents) varied from 2.3 to 56.0 micrograms/l on the margin of the pond and between 1.7 and 4.6 micrograms/l in the outflow of this pond. These values indicate that WWTP may be a source of contamination of water bodies with cyanobacteria toxins.

[How to determine the diagnosis of Helicobacter pylori infection in the elderly?]

PURPOSE

The real prevalence of Helicobacter pylori (H. pylori) infection is difficult to determine in the elderly because of the frequency of drug intake (antibiotics or anti-secretory drugs). The aim of this study was to evaluate the diagnostic performance of five tests in the elderly.

METHODS

The study population consisted of consecutive patients undergoing a routine endoscopy between August 1998 and December 1999. We evaluated the diagnostic performance of four tests in all of the included patients: culture and histology of biopsy specimens, serology (ELISA) and urea breath test (13C-UBT). Detection of H. pylori antigens in stool samples (HpSA) was realized in a subgroup. Patients were considered H. pylori + when result for culture was positive or when two tests were positive.

RESULTS

One hundred and sixty-seven patients were included in this study (55 men, 112 women; mean age: 85.6 +/- 5.1 years). Only 38 (22.8%) patients were H. pylori+. Test performances showed the following results: serology sensitivity: 90.9% (IC 95%: 75.6-98.1) versus 86.9% (IC 95%: 63.6-96.9) for culture versus 77.8% (IC 95%: 60.8-89.9) for histology and 74.3% (IC 95%: 56.7-87.5) for 13C-UBT. Eighty-nine (53.3%) took antibiotics or anti-secretory drugs, only 13C-UBT performances decreased significantly (sensitivity: 94.4% [72.7-99.8] versus 52.9% [27.8-77]; P < 10(-6)). When gastric or duodenal ulcer were endoscopically diagnosed in older patients, both histology and 13C-UBT could not improve the diagnosis of H. pylori infection. HpSA was realized in 107 patients (sensitivity: 74.1%, specificity: 98.7%). We showed no statistical difference between HpSA performances and drug intake.

CONCLUSION

Diagnostic performances decreased in older patients especially because of drug intake.

Análise genética da idade ao primeiro parto e do perímetro escrotal em bovinos da raça Nelore

Com o objetivo de estudar as características idade ao primeiro parto (IPP) e perímetro escrotal (PE) e sua relação com características de desempenho ponderal em um rebanho bovino da raça Nelore, linhagem Lemgruber, analisaram-se 2.796 observações para IPP, 2.746 para PE, 3.657 para peso à desmama e 4.686 para peso ao sobreano. As análises foram processadas utilizando-se de modelos animais bi e tricaracterística (com peso à desmama ou peso ao sobreano como terceira característica). Peso ao sobreano foi incluído como covariável para PE em duas análises, visando ajustar o PE para peso corporal. Os coeficientes de herdabilidade para IPP e PE variaram de 0,09 a 0,10 e de 0,33 a 0,34, respectivamente. A correlação genética entre IPP e PE variou de -0,23 a -0,29. A correlação negativa não permite descartar a utilização do perímetro escrotal como critério de seleção para precocidade sexual. Análises multicaracterísticas que incluem o peso ao sobreano parecem mais adequadas à avaliação da idade ao primeiro parto e do perímetro escrotal medido aos 18 meses.

Endoscopic findings in chronic lymphocytic leukemia

Retrospective studies, based on autopsy findings, indicate that infiltration of the gastrointestinal tract complicates leukemia of all types and may be present from the esophagus to the rectum. This report presents what is believed to be the first reported case of a patient with chronic lymphocytic leukemia with evidence of esophageal, gastric, duodenal bulb, and colonic involvement confirmed by mucosal biopsy at endoscopy.

Mutation analysis of interleukin-5 in an asthmatic cohort

Interleukin-5 (IL-5) is a potential candidate gene in the pathogenesis of asthma, as it is the main cytokine controlling eosinophil activity and eosinophils are pivotal in the development of airway inflammation. Mutation detection studies were performed on the IL-5 gene and the alpha-chain of its receptor in 30 asthmatic and 30 nonasthmatic subjects. Single-strand conformational polymorphism (SSCP) and heteroduplex analysis (HA) did not reveal any change from the reported normal sequence in all 4 exons of IL-5 as well as the promoter and 3'-untranslated regions of the gene. No SSCP variations were seen within the complete coding sequence of the IL-5 receptor alpha-chain. Mutations of the IL-5 gene coding region, its promoter and receptor are unlikely to be common causes of an inherited predisposition to asthma.

Structural study of the interaction of vanadate with the ligand 1,2-dimethyl-3-hydroxy-4-pyridinone (Hdmpp) in aqueous solution

The interaction of vanadate with the ligand 1,2-dimethyl-3-hydroxy-4-pyridinone (Hdmpp) was studied in aqueous solution using a combination of multinuclear NMR and EPR spectroscopies, as well as potentiometry and cyclic voltammetry. The different species in solution were identified and characterized, and their pKa values and stability constants determined. The vanadium complexes formed in solution are strongly dependent on media composition (ionic strength, presence of buffer), pH and metal-to-ligand ratio (M:L). Two major species--V(V)/dmpp and V(V)/(dmpp)2--are formed in a 140 mM NaCl solution within the pH range 4.5 to 9.0, when M:L = 1:2. In the presence of excess ligand (M:L < or = 1:5), only the 1:2 complex is present, and at pH < 4 paramagnetic species are detected by EPR in solution, thus indicating a reducing capacity of the ligand. Cyclic voltammetry shows that redox processes in solution are not just electron transfer, but are accompanied by chemical reactions. The pK, values and stability constants were determined both by 51V NMR spectroscopy and potentiometry. The present results have a particular interest in the understanding of the aqueous solution chemistry in aerobic conditions of bis(1,2-dimethyl-3-hydroxy-4-pyridinonato) oxovanadium(IV) complex, VO(dmpp)2, a vanadium compound with potential insulin-mimetic properties.

[Influence of the equality of ventricular pressure in the echocardiographic determination of the ejection fraction of the left ventricle]

OBJECTIVES

Limited data have been reported concerning the influence of right ventricular systolic overload on the accuracy of the 2D echocardiographic (echo) determination of left ventricular (LV) ejection fraction (EF). The normal newborn at birth (high pulmonary peak systolic pressure) and just after the fall of pulmonary pressure, represent an in vivo model to study this influence. This study compares the LVEF determined by recommended 2D echocardiographic algorithms with that by 3D echo, in newborns at birth and just after the normal fall of right ventricular systolic pressure.

METHODS

100 echocardiographic studies (50 at 2 to 6 hours after birth--group I; and 50 at 7 to 14 days old--control group) were performed in 82 normal newborns, to determine LVEF by 4 geometric models (cylinder hemiellipsoid; ellipsoid biplane; single plane area length, in 4- and 2-chamber view; biplane method of discs) and visual estimation, using 3D echocardiography as the reference method.

RESULTS

In group I, the correlation between 3D echo and cylinder hemiellipsoid was r = 0.62 (SEE = 4.5%); ellipsoid biplane, r = 0.69 (SEE = 4.1%); single plane area length, 4 chambers, r = 0.66 (SEE = 5.1%) and, 2 chambers, r = 0.72 (SEE = 4.0%); biplane method of discs, r = 0.83 (SEE = 3.6%), and, visual estimation, r = 0.78 (SEE = 3.5%). In the control group, the correlation between 3D echo and cylinder hemiellipsoid was r = 0.70 (SEE = 3.4%); ellipsoid biplane, r = 0.63 (SEE = 3.4%); single plane area length, 4 chambers, r = 0.79 (SEE = 3.5%) and, 2 chambers, r = 0.76 (SEE = 4.1%); biplane method of discs, r = 0.90 (SEE = 2.3%), and, visual estimation, r = 0.64 (SEE = 3.9%).

IN CONCLUSION

These data suggest that the biplane method of discs and single plane area length using 2-chamber view allows a more accurate LVEF determination when significant right ventricular pressure overload is present.

Kinetic analysis in living cells of the inhibition of the P-glycoprotein-mediated efflux of anthracyclines by vinca alkaloids

Cells that overexpress the mdr 1 gene have decreased steady-state accumulation and increased efflux of many anticancer drugs including anthracyclines and vinca alkaloids. The mechanism(s) of P-glycoprotein-mediated efflux of drugs is (are) still poorly understood. In an attempt to identify mechanism(s) by which multidrug resistance can be circumvented, the cellular accumulation has been examined of pirarubicin, doxorubicin and idarubicin alone and in conjunction with four vinca alkaloid derivatives--vinblastine, navelbine, vindesine and vincristine. The present study was performed using a spectrofluorometric method with which it is possible to follow continuously the uptake and release of fluorescent molecules by living cells, as the incubation of the cells with the drug proceeds. Erythroleukemia K562 cell lines were used. It has been shown that the P-glycoprotein-mediated efflux of these three anthracyclines can be inhibited by vinca alkaloids derivatives. At pH 7.2, 50% of the P-glycoprotein-mediated efflux of daunorubicin and idarubicin was inhibited by about 40 +/- 10 microM vinblastine and that of pirarubicin by 10 +/- 2 microM vinblastine. The vinblastine concentration required to inhibit 50% of the active efflux of these anthracyclines did not depend on the anthracycline concentrations used, indicating that the inhibition was non competitive. The ability of navelbine, vincristine and vindesine to inhibit the active efflux of pirarubicin was also checked; 15 +/- 3 microM navelbine are required to inhibit 50% of the active efflux but at concentrations lower than 100 microM, neither vincristine nor vindesine were able to inhibit this efflux, indicating that the vinca alkaloids compounds which are the most efficient are the most lipophilic. For the four vinca alkaloids, the concentration required to inhibit 50% of the efflux was lower as the pH was higher. A detailed kinetics analysis of the P-glycoprotein-mediated efflux of pirarubicin in the presence of vinblastine indicates a non competitive inhibition with K(I) = 12 +/- 2 microM.

Cardiac consequences of renal transplantation changes in left ventricular morphology

OBJECTIVE

The aim of this study was to characterize changes in left ventricular morphology and function by conventional echocardiography in a pediatric population after renal transplantation (RT).

MATERIAL AND METHODS

This study includes 21 children, 11 female and 10 male, aged 11.8 +/-2.6 years at the time of renal transplantation. Eleven were on regular hemodialysis treatment and two on continuous peritoneal dialysis for 31.8 +/- 31.6 months; eight were transplanted without prior dialysis. Eight children were hypertensive before RT and nine (seven de novo) after RT. The patients were analysed in a prospective follow-up study with echocardiography immediately before and 30.2 +/- 15 months after successful renal transplantation. We measured the following echocardiographic parameters: Left ventricular end diastolic (LVED) and end systolic diameter (LVES), left atrial dimension (LAD), septal thickness (IVST), posterior wall thickness (PWT), shortening fraction (SF) and left ventricular index mass (LVIM). The paired Student's test, Fisher exact test and Pearson's correlation were used for statistical analysis. We analyzed the echocardiographic changes in the total group and separately in the subgroups with and without prior hemodialysis, as well as the influence of the duration of dialysis, anemia and hypertension.

RESULTS

1. After renal transplantation we found a decrease in the LVED LVES, LAD, IVST and PWT measurements (p < 0.05). There was a negligible increase in SF. The LVIM decreased from 139 g/m2 to 104 g/m2, representing a 21% reduction of the initial value, but this reduction was not of statistically significant. 2. The findings were similar in the hemodialysis group-LVIM decreased from 167.6 g/m2 to 94.9 g/m2, representing a 35% reduction in the initial value. 3. In the non dialysis group LVED, LVES, LAD and SVT decreased and LVIM showed a minor increase. There was a negligible increase in SF. 4. We found an increased LVIM in children with prior hemodialysis before RT, especially if dialysis lasted for more than two years. 5. Amelioration of hematocrit correlated with reduction of LVIM. 6. Regression of LV hypertrophy after RT was not dependent on blood pressure levels.

CONCLUSIONS

Renal transplantation resulted in a tendency towards normalization of the echocardiographic parameters analysed: Contractility, as assessed by shortening fraction, was normal in this population. Although cardiac hypertrophy and dilation is reversible after RT, it would seem that children may benefit from an earlier transplantation.

Mutation screening of interferon-gamma (IFNgamma) as a candidate gene for asthma

BACKGROUND

Reduced levels of interferon gamma (IFNgamma) mRNA and protein have been detected in the bronchoalveolar lavage fluid of atopic asthmatics. IFNgamma is secreted by TH1 cells while IL-4 and IL-5 are secreted by TH2 cells and an imbalance in the TH1/TH2 response may be responsible for atopic asthma. The gene for IFNgamma is located on chromosome 12; a region of the genome which has been shown in linkage studies to be associated with asthma.

OBJECTIVE

To determine if there are any mutations present in the coding exons and 5' flanking region of the IFNgamma gene in atopic asthmatic subjects compared with controls to explain the lower levels of this cytokine as an inherited, rather than acquired, factor in the asthmatic subjects.

METHODS

The four exons and 5' flanking region of the IFNgamma gene were amplified by polymerase chain reaction (PCR) from genomic DNA of 265 individuals from a Western Australian and a Venezuelan population. The PCR products were examined by single strand conformational polymorphism and heteroduplex analyses to see if there were any changes in the DNA migration patterns which would suggest the presence of a sequence variation.

RESULTS

The four exons and the 5' flanking region of the IFNgamma gene were amplified from 265 individuals from two populations. Single strand conformational polymorphism and heteroduplex analyses did not reveal any mutations in the regions examined.

CONCLUSION

The gene for IFNgamma appears to be highly conserved as no sequence variations were detected in 265 individuals. These results suggest that mutations of the IFNgamma gene are unlikely to be a significant cause of an inherited asthma diathesis.

Comparison of left ventricular ejection fraction in congenital heart disease by visual versus algorithmic determination

Two-dimensional (2D) echocardiographic visual estimation of left ventricular (LV) ejection fraction (EF) in patients with acquired heart disease yields results that are comparable to those obtained by recommended algorithms. However, there is no information concerning its accuracy in congenital heart disease. This study compares applicability, accuracy, and reproducibility of LVEF by visual estimation with that by currently used algorithms (cylinder hemiellipsoid, ellipsoid biplane, and biplane method of disks) in 92 consecutive patients with congenital heart disease but unrepaired complete atrioventricular septal defect, univentricular heart, and hypoplastic left ventricle, using 3D echocardiography as the reference method. Visual estimation of LVEF could be applied in all cases. Because of technically inadequate 2D echocardiographic images for volume measurement, analysis for comparison could be performed in 71 patients (77%), aged 1 day to 47 years. The correlation between 3D echocardiographic and visual estimation was 0.91 (SEE 3.3%), cylinder hemiellipsoid, 0.86 (SEE 3.9%), ellipsoid biplane 0.87 (SEE 3.9%), and biplane method of disks 0.93 (SEE 3.2%). Intraobserver variability was similar for all 2D echo methods. Interobserver variability was greater for visual estimation. In conclusion, visual estimation of LVEF is applicable to most patients with congenital heart disease, yielding results that are comparable to those obtained by currently used 2D echocardiographic algorithms.

[Contribution to the anatomical study of medial arm flap]

The reports of transfer of the medial arm flap have been inconsistent, and confusion remains about its anatomy and use. The advantages of this donor site, however, justify new researches about the vascular anatomy of the flap. In this study, the vascular supply to the medial side of the arm was analysed in fifteen fresh cadaver dissections. The methods, the anatomical bases, and the technique of elevation of the flap were detailed. Methylene blue injection studies showed the extent of the medial arm flap. The authors found that, in most cases, the superior ulnar collateral artery was the main vessel of this flap, giving cutaneous branches to medial arm skin. The diameter of the superior ulnar collateral artery was measured and considered adequate for microsurgical transfer. If no major cutaneous branches are noted from superior ulnar collateral artery, then a significant direct cutaneous branch from the brachial artery will be always present. With this in mind, the dissection must initially proceed carefully, preserving all vessels that may contribute to cutaneous perfusion. The authors conclude that with knowledge of its anatomical variations, the medial arm flap is a plausible reconstructive option.

[Surgical myocardial revascularization in young patients]

PURPOSE

To determine early and late results of surgical myocardial revascularization (SMR) in young patients.

METHODS

We studied retrospectively 73 patients aging less than 40 years and submitted to SMR between 1975 and 1989. The method used was patient card review and thelephone contact with the patient or his physician.

RESULTS

Follow-up was obtained in all cases in a period of 2 to 185 (59.9 +/- 41.0) months. Of the coronary risk factors smoking was the most frequent. One vessel coronary artery disease was observed in 16 (21.9%) patients, 2 and 3 vessel coronary artery disease in 26 (35.6%) and 32 (43.8%) patients respectively. SMR was considered complete in 68 (93.2%) patients. An associated procedure was performed on 10 cases: Left ventricular aneurysm repair in 9 (12.3%) and mitral valve replacement in one (1.4%). Perioperative myocardial infarction occurred in 7 (9.5%) patients and one of them died (operative mortality: 1.4%). During follow-up, 6 (8.3%) patients died with an actuarial survival rate of 89.1% at 15 years. An event free survival rate of 68.3% was observed at 10 years. From 66 survivors, 53 (80.3%) were asymptomatic at late follow-up and 48 (72.7%) patients returned to work.

CONCLUSION

Surgical myocardial revascularization in young patients associated with medical treatment, has good early and late results with a high percentage of patients asymptomatic and reemployed at a late follow-up.

Correlation between in vitro resistance to fluconazole and clinical outcome of oropharyngeal candidiasis in HIV-infected patients

Fifty episodes of oropharyngeal candidiasis in HIV-infected patients were analyzed prospectively in order to evaluate the clinical response to fluconazole. The minimum inhibitory concentrations (MICs) of fluconazole for the Candida strains isolated from the pharynx were correlated with the clinical response. Treatment with fluconazole (100 mg/day) was successful in 86% of the cases. A good clinical outcome followed in 97% of the cases when a strain sensitive to fluconazole was isolated. This figure fell to 22% when the strain was resistant to fluconazole (p < 0.001). The rate of post-treatment colonization was high (87%), and selection of non-albicans Candida species occurred in 23% of the cases. In conclusion, fluconazole treatment for oropharyngeal candidiasis of HIV-infected patients was useful in most cases, but less sensitive non-albicans species can be selected. Most treatment failures were associated with increased MICs of fluconazole for the strains isolated before treatment; therefore, susceptibility testing is recommended as an aid in clinical decision-making for the use of the azole group of drugs.

Recurrent and novel LDL receptor gene mutations causing heterozygous familial hypercholesterolemia in La Habana

The molecular basis of familial hypercholesterolemia (FH) in three families of Spanish descent from La Habana was investigated by the candidate gene approach. The Arg3500Gln mutation of apolipoprotein B-100 was not found. Identification of low density lipoprotein receptor (LDLR) gene haplotypes segregating with FH guided the characterisation of three point mutations by automated sequencing. One, a Val408-->Met missense mutation, a founder mutation in Afrikaner FH patients, was recurrent, being associated with a distinct DNA haplotype. The other two, Glu256-->Lys and Val776-->Met missense mutations, were novel and modified highly conserved residues. These mutations were absent in normolipidemic subjects and were associated in heterozygous carriers with twice the cholesterol levels observed in non-carriers. Noticeably, cardiovascular complications were rarely observed in older heterozygotes, even in those with the Afrikaner FH-2 mutation. These findings confirm the molecular heterogeneity of LDLR gene mutations causing FH and the variability of their expression across different populations.

Reversal of multidrug resistance by verapamil analogues

The basic distinguishing feature of multidrug resistant (MDR) cells is a decrease in steady-state drug levels as compared to drug-sensitive controls. It is well-known that verapamil increases the sensitivity of MDR cells to drugs, thus reverting drug resistance. A limiting factor for its clinical use is the pronounced cardiovascular effects of the calcium channel antagonist which occur at the high plasma concentrations required to block P-glycoprotein transport efficiently. From a clinical point of view, it is important to find verapamil derivatives with low calcium channel blocking activity and high reverting activity. This was the aim of the present study. In this context we have investigated the ability of 20 verapamil analogues with restricted molecular flexibility to increase cellular accumulation of anticancer drugs and overcome resistance, and their inotropic, chronotropic, and slow calcium channel antagonistic activity. In this study an anthracycline derivative 4'-O-tetrahydropyranyl adriamycin, and an erythroleukaemia K562 cell line were used. Three of the 20 derivatives checked were completely devoid of calcium channel blocking activity while exhibiting MDR reverting ability comparable to that of verapamil. These derivatives could be useful for the treatment of MDR in cancer patients and for the design and development of other verapamil derivatives.

[Adequacy of of pacemakers responsive to the volume-minute ventilation rate in heart transplantation patients]

PURPOSE

To evaluate in the late post-operative period (PO) the chronotropic response to exercise of patients submitted to orthotopic cardiac transplantation (CT) and the implant of a cardiac pacemaker (PM).

METHODS

A rate response ventricular PM (VVI+R) which uses minute ventilation (MV) as a sensor was implanted in five patients in the early PO of CT due to chronotropic incompetence. The patients were 31 to 64 years old and the indication to implant of PM was low ventricular escape rhythm following atrial taquicardia/bradycardia (one case) or sinus bradycardia (4 cases). The study was performed by means of paired exercise tests using Naughton protocol in order to compare the heart rate in VVI (prefixed heart rate) and VVIR+MV (rate response) mode. The duration of the exercise was compared between the two modes of stimulation.

RESULTS

In VVI mode the heart rate was significantly lower than in VVIR+MV mode for comparable periods of exercise (101 +/- 12 ppm vs 132 +/- 4 ppm; p < 0.05); in VVIR+MV mode the patients had a prolonged time of exercise as compared to VVI mode (15 +/- 7 min vs 12 +/- 7 min; NS).

CONCLUSION

The MV rate response PM provided patients with satisfactory heart during exercise and may be an adequate option to patients submitted to CT who present chronotropic incompetence.

Evidence for adenine methylation within the mouse myogenic gene Myo-D1

Previous studies have indicated that there may be uncleavable TaqI sites (TCGA) within the mouse myogenic gene, Myo-D1. Fragments of DNA bearing most of the presumed insensitive TaqI sites have been reproduced using PCR. The presence of each of the originally uncleavable TaqI sites has been confirmed and each TaqI site has been shown to be sensitive to TaqI hydrolysis in PCR-synthesized genomic DNA. Since TaqI is inhibited by methylation of the adenine residue within its recognition sequence (but not by cytosine methylation), it is suggested that specific adenine bases are methylated in the coding region of Myo-DI and maintained throughout cell division. The same TaqI recognition sequences are insensitive to digestion in genomic DNA isolated from various mouse tissues including fetus, regenerating skeletal muscle and a myogenic cell line, all of which express Myo-D1. Thus, adenine methylation is not a modification of DNA following gametic fusion nor does it appear to play a major role in regulation of Myo-D1 expression.

Aprotinin in children undergoing correction of congenital heart defects. A double-blind pilot study

Thirty children undergoing surgical repair for congenital heart defects were randomly selected for a double-blind study on the anti-hemorrhagic and blood-saving properties of aprotinin. The treatment group comprised 14 patients who received aprotinin 7 mg/kg of body weight until the end of perfusion. The placebo group (n = 16) received an infusion of the corresponding volumes of saline. Patients treated with aprotinin bled less during the operation (12.6 ml/kg versus 18.1 ml/kg, p = 0.25) and in the first 24 postoperative hours (chest drainage 12.1 ml/kg versus 17.7 ml/kg, p = 0.07). Hemoglobin loss into chest drainage was reduced in the treated group by half (0.66 versus 1.21 gm in 24 hours, p = 0.07). Fewer blood donors were needed during hospitalization by patients receiving aprotinin (1.07 versus 2.75 donors per patient, p = 0.04). Postoperative transfusion was unnecessary in 64.2% of patients receiving aprotinin compared with only 25% of the placebo group (p = 0.03). Aprotinin increased diuresis significantly during perfusion (4.3 ml/kg versus 1.0 ml/kg, p = 0.005). Other parameters are evaluated, and considerations are made regarding adequacy of the dosage regimen. The drug seems to be safe and easy to handle in children.