Detection of 16SrIV-A phytoplasma DNA in Colpoptera sp. (Hemiptera: Nogodinidae) insects in Yucatan Peninsula, Mexico.

Lethal yellowing (LY) is a disease that affects coconut and other palm species. It is associated to phytoplasmas of the group 16SrIV and the only reported insect vector for this pathogen so far is Haplaxius crudus. H. crudus is present in Mexico and has been associated to 16SrIV phytoplasmas, however, it was not detectable during a LY outbreak in the coast of Yucatan, Mexico, suggesting the existence of other vector species. To test this hypothesis a survey of insects was carried out and a total of 3074 insects were captured during a year of monthly sampling. Ten taxonomic orders were identified in this sample, Hemiptera being the most abundant (N=2094), and these were classified into nine families. The leafhopper Colpoptera sp. from to the Nogodinidae family was de most abundant representing 56% of the total number of insects sampled and 23% of these samples resulted positive for LY phytoplasma by PCR detection. The BLAST comparison, virtual RFLP and phylogenetic analyses of the sequenced amplicons relate the detected phytoplasma to the subgroup 16SrIV-A. The findings presented herein suggest that Colpoptera sp. could be considered as a new putative vector of the LY-causing phytoplasmas in Mexico and a candidate for further research.

Granuloma caused by Acanthocheilonema spp. in a canine: case report / [Granuloma por Acanthocheilonema spp. em um cão: relato de caso]

A canine patient, 13-year-old mixed breed male, 24kg, was seen at a private clinic in the city of Guayaquil, Ecuador. The main reason for consultation was the evaluation of a mass in the right knee and neck that had previously been cytologically diagnosed of neoplastic origin by another team of veterinarians through fine needle puncture and cytology. The contacts were asymptomatic. At the time of the consultation, a detailed exploration and complementary methods were performed that included hematological and urinary exams, mass cytology, serological test, chest radiography and biopsy for further histopathological study. The final diagnosis was a cutaneous granuloma due to microfilariae of Acanthocheilonema spp. and its subsequent surgical and medical treatment with excellent results. The canine heartworm is a cosmopolitan disease caused by nematodes of the genus Dirofilaria, with D. immitis being the best-known species. Less frequently, the species Acanthocheilonema spp., found in this patient, is also reported in Americas, with little knowledge about it. This is the first report of its kind hoping that it will serve as a basis for future studies.

Foi atendido, em uma clínica particular, na cidade de Guaiaquil, Equador, um paciente canino, sem raça definida, de 13 anos de idade, macho, não castrado, de 24kg. O motivo da consulta foi a avaliação de uma massa em região de articulação de joelho direito e de pescoço, que havia sido previamente diagnosticada como de origem neoplásica por outra equipe de médicos veterinários, mediante punção por agulha fina e citologia. Os contactantes eram assintomáticos. No momento da consulta, realizaram-se detalhadas avaliações clínica e complementar, que incluíram exames hematológicos, urinálise, citologia da massa, teste sorológico, radiografia torácica e biopsia para posterior estudo histopatológico. O diagnóstico final foi granuloma cutâneo por microfilária de Acanthocheilonema spp., para o qual os tratamentos clínico e cirúrgico apresentaram excelentes resultados. A dirofilariose é uma enfermidade cosmopolita causada por nematódeos do gênero Dirofilaria, sendo a espécie D. immitis a mais conhecida. Em menor frequência, a espécie Acanthocheilonema spp. encontrada neste paciente é também relatada na América, existindo pouco conhecimento a seu respeito. Este é o primeiro relato de caso sobre este tema e espera-se que sirva como base para futuros estudos.

Increased tissue factor and thrombomodulin expression and histopathological changes in placentas of pregnancies with preeclampsia.

INTRODUCTION: Preeclampsia has a global frequency of 2-8% and a frequency of 10% in developing countries. In Colombia, preeclampsia causes 42% of maternal mortality. Alterations in placental homeostasis have been proposed to be involved in its pathophysiology. The aim of this study was to compare mRNA and protein levels of tissue factor (F3) and thrombomodulin (THBD) and the histopathological findings of placentas. MATERIALS AND METHODS: We studied 16 placentas from patients with preeclampsia and 19 term placentas with uncomplicated pregnancy. An expert pathologist, who was masked to the group assignment, conducted an evaluation to determine specific histological changes. Assessments of mRNA and protein levels of F3 and THBD were performed using real-time PCR and ELISA, respectively. RESULTS: Cases and controls differed in the frequency of decidual arteriopathy (p = 0.027), acute infarction (p = 0.001) and hyperplasia of the syncytiotrophoblast (p = 0.0017). Cases had increased levels of F3 mRNA (p = 0.0124) and protein (p <  0.0001) and THBD mRNA (p <  0.0001) and protein (p <  0.0001). CONCLUSION: In placenta of patients with preeclampsia, we detected abnormal expression of F3 and THBD with increased protein and mRNA levels. The role of these molecules in the pathogenesis of this disease and in alterations of hemostatic and histopathological aspects of placentas need further studying.

Aggregation and adsorption behavior of low concentration aqueous solutions of hexadecyltrimethylammonium ortho, meta, and parafluorobenzoate.

The aggregation properties of 2-, 3-, and 4-fluorobenzoic acids (2FBA, 3FBA, and 4FBA, respectively) and their salts with hexadecyltrimethylammonium cations (HTA2FB, HTA3FB, and HTA4FB) in water were studied with a battery of techniques. Their activity at the air/solution interface has been also studied. The position of the fluorine atom in the acid affected the solubility, adsorption, and aggregation in the pure acids solutions. The 4FBA is less water soluble, more hydrophobic, and has the lower critical aggregation concentration of the three isomers. The behavior of the HTA2FB compound in aqueous solution is different from that of HTA3FB and HTA4FB. The critical micelle concentration, critical concentration for sphere-to-rod-like micelle transition, and Krafft point of HTA3FB and HTA4FB are lower than those of the other surfactant but their surface activities are higher. The differences between the HTA2FB and the other two surfactants have been explained on the basis of the regular solution theory of mixed micelles and in light of the analysis of the hydration shell of the acids through molecular dynamic simulations. The results of the present work suggest that the different behaviors are due to a combination of different dehydration tendencies and the steric possibility of inclusion of the counterions in the micelle palisade layer. The formation of rod-like micelles by HTA2FB, while the tetradecyltrimethylammonium 2-fluorobenzoate only forms spherical aggregates, is explained on the basis of the packing parameter. The mentioned factors are complementary to others presented in literature. These conditions may be used in the rational design of micelles by means of molecular dynamics simulations, reducing the trial-and-error approach used to date.

Epidemiology of bovine tuberculosis in Mexico, bordering the United States, at establishment of controlling strategies / Epidemiologia da tuberculose bovina na fronteira do México com os Estados Unidos, por ocasião do estabelecimento das estratégias de controle

A case-control study was carried out for determining epidemiological patterns at the beginning of the Mexican campaign against bovine tuberculosis (BTB) in the State of Tamaulipas, Mexico, bordering the United States of America. From January 1995 to March 1998, 599 direct tissue smears of cattle from routine slaughterhouse inspection were analyzed for the presence of Mycobacterium bovis acid-fastness with Ziehl-Neelsen stain. BTB status was associated with year of diagnosis, age, breed, geographical origin of cattle, and type of slaughterhouse using the odds ratio (OR) (95 percent confidence level). The prevalence at slaughterhouse surveillance was 15.36 percent, which was considerably higher in 1995 (41.38 percent, OR=5.78, P<0.0001), in comparison with 8.09 percent, 14.42 percent, and 10.14 percent for the years 1996, 1997, and 1998, respectively. BTB was associated with cattle from the State of Tamaulipas (19.73 percent, OR= 4.438, P=0.01), adult cattle (19.13 percent, OR=2.19, P<0.0001), Bos taurus (22.54 percent, OR=2.135, P<0.0001) and B. taurus x B. indicus cross bred animals (29.31 percent, 2.769, P<0.0001), and cattle slaughtered at federal inspected abattoir (17.58 percent, OR=1.23, P<0.0001).

O estudo foi realizado para determinar os padrões epidemiológicos no início da campanha mexicana contra a tuberculose bovina (BTB), no Estado de Tamaulipas, fronteira com os Estados Unidos da América. De janeiro de 1995 a março de 1998, 599 amostras de tecidos bovinos, obtidas em inspeção de rotina em abatedouros, foram analisadas para a presença de Mycobacterium bovis, fixadas em corante Ziehl-Neelsen. O status BTB foi associado ao ano do diagnóstico, idade, raça e origem geográfica do bovino utilizando a razão de probabilidade (OR) (com intervalo de confiança de 95 por cento). A prevalência no abatedouro sob inspeção foi de 15,36 por cento, consideravelmente maior em 1995 (41,38 por cento, OR=5,78), P<0,0001) em relação a 8,09 por cento, 4,42 por cento e 10,14 por cento para 1996, 1997 e 1998, respectivamente. Houve associação entre BTB e animais provenientes do estado de Tamaulipas (19,73 por cento; OR=0.438; P=0.01), idade adulta (19,13 por cento; OR=2,19; P<0,0001), Bos taurus (22,54 por cento; OR=2,135; P<0,0001) e cruzamentos B. taurus x B. indicus (29,31 por cento; 2,769; P<0,0001), e animais abatidos em abatedouros federais inspecionados (17,58 por cento; OR=1,23; P<0,0001).

Epidemiology of bovine tuberculosis in Mexico, bordering the United States, at establishment of controlling strategies / Epidemiologia da tuberculose bovina na fronteira do México com os Estados Unidos, por ocasião do estabelecimento das estratégias de controle

A case-control study was carried out for determining epidemiological patterns at the beginning of the Mexican campaign against bovine tuberculosis (BTB) in the State of Tamaulipas, Mexico, bordering the United States of America. From January 1995 to March 1998, 599 direct tissue smears of cattle from routine slaughterhouse inspection were analyzed for the presence of Mycobacterium bovis acid-fastness with Ziehl-Neelsen stain. BTB status was associated with year of diagnosis, age, breed, geographical origin of cattle, and type of slaughterhouse using the odds ratio (OR) (95 percent confidence level). The prevalence at slaughterhouse surveillance was 15.36 percent, which was considerably higher in 1995 (41.38 percent, OR=5.78, P<0.0001), in comparison with 8.09 percent, 14.42 percent, and 10.14 percent for the years 1996, 1997, and 1998, respectively. BTB was associated with cattle from the State of Tamaulipas (19.73 percent, OR= 4.438, P=0.01), adult cattle (19.13 percent, OR=2.19, P<0.0001), Bos taurus (22.54 percent, OR=2.135, P<0.0001) and B. taurus x B. indicus cross bred animals (29.31 percent, 2.769, P<0.0001), and cattle slaughtered at federal inspected abattoir (17.58 percent, OR=1.23, P<0.0001).(AU)

O estudo foi realizado para determinar os padrões epidemiológicos no início da campanha mexicana contra a tuberculose bovina (BTB), no Estado de Tamaulipas, fronteira com os Estados Unidos da América. De janeiro de 1995 a março de 1998, 599 amostras de tecidos bovinos, obtidas em inspeção de rotina em abatedouros, foram analisadas para a presença de Mycobacterium bovis, fixadas em corante Ziehl-Neelsen. O status BTB foi associado ao ano do diagnóstico, idade, raça e origem geográfica do bovino utilizando a razão de probabilidade (OR) (com intervalo de confiança de 95 por cento). A prevalência no abatedouro sob inspeção foi de 15,36 por cento, consideravelmente maior em 1995 (41,38 por cento, OR=5,78), P<0,0001) em relação a 8,09 por cento, 4,42 por cento e 10,14 por cento para 1996, 1997 e 1998, respectivamente. Houve associação entre BTB e animais provenientes do estado de Tamaulipas (19,73 por cento; OR=0.438; P=0.01), idade adulta (19,13 por cento; OR=2,19; P<0,0001), Bos taurus (22,54 por cento; OR=2,135; P<0,0001) e cruzamentos B. taurus x B. indicus (29,31 por cento; 2,769; P<0,0001), e animais abatidos em abatedouros federais inspecionados (17,58 por cento; OR=1,23; P<0,0001).(AU)

Phase and rheological behavior of the hexadecyl(trimethyl)azanium; 2-hydroxybenzoate/water system.

The phase and rheological behavior of hexadecyl(trimethyl)azanium; 2-hydroxybenzoate (CTAS), and water as a function of surfactant concentration and temperature are investigated here. The critical micellization concentration (cmc(1)) and the concentration at which the structure of aggregates changes (cmc(2)) as well as the Krafft temperature (T(K)) are reported. A large micellar solution region exhibiting high viscosity, as well as hexagonal- and lamellar-phase regions were identified. In the dilute region, below the overlapping entanglement concentration (C*), the micellar solutions exhibit shear thickening. Above C*, wormlike micelles form and the solutions show strong viscoelasticity with Maxwell behavior in the linear regime and shear banding flow in the non-linear regime. The linear viscoelastic regime was analyzed with the Granek-Cates model, showing that the relaxation is controlled by the kinetics of reformation-and-scission of the micelles. The steady response in the non-linear regime is compared with the predictions of the Bautista-Manero-Puig (BMP) and the Giesekus models.

Surface and bulk properties of aqueous decyltrimethylammonium bromide-hexadecyltrimethylammonium bromide mixed system.

The aqueous mixed system decyltrimethylammonium bromide (C(10)TAB)-hexadecyltrimethylammonium bromide (C(16)TAB) was studied by conductivity, ion-selective electrodes, surface tension, and fluorescence spectroscopy techniques. The mixture critical micelle concentration, cmc(*), aggregation number, N( *), and micelle molar conductivity, Lambda(M)(cmc), showed that the system aggregation is strongly nonideal. Both cmc(*) and N( *) results were analyzed with two different procedures: (i) the regular solution theory on mixed micelles or Rubingh's theory, and (ii) by the determination of the partial critical micelle concentration of the amphiphile component i in the presence of a constant concentration of the other amphiphile component, cmc(i)( *). The Rubingh procedure gives micelles richer in C(16)TAB than the overall mixtures, while procedure (ii) gives micelles having the same composition as in the complete surfactant mixture (alpha(C(10)TAB). Mixed micelles are larger than pure surfactant ones, with nonspherical shape. Using a literature model, the cause of the synergistic effect seems to be a reduction of the hydrocarbon/water contact at the micelle surface when mixed micelles form. Conductivity and ion-selective electrodes indicate that highly ionized premicelles form immediately before the cmc(*). The air/solution interface is strongly nonideal and much richer in C(16)TAB than the composition in the bulk. When micelles form there is a strong desorption from the air/solution interface because micelles are energetically favored when compared with the monolayer.

Prospective study using standardized methodology for antimicrobial susceptibility of gram-positive cocci isolated from the Puerto Rico Medical Center

The Gram-positive cocci (GPC), Staphylococcus aureus, Streptococcus pneumoniae, Enterococcus faecalis and Enterococcus faecium, have become important causes of community and nosocomial-acquired infections. The prevalence of multiple resistant isolates to standard antimicrobial drugs has significantly increased over the past decades. Few prospective studies have been performed in Puerto Rico (PR) concerning the GPC antimicrobial susceptibilities pattern. The purpose of this study was to evaluate the in vitro susceptibility of GPC clinical isolates from PR to selected standard antibiotics and to the new antimicrobial agents, linezolid (LZ), quinupristin/dalfopristin (Q/D) and gemifloxacin (GM). The in vitro susceptibility utilizing disk diffusion and Etest methods to selected antibiotics was determined for a total of 429 isolates obtained during a period of 5 months from the Puerto Rico Medical Center Bacteriology Laboratory. The distribution of GPC collected was as follows: 213 S. aureus isolates, 162 E. faecalis, 16 E. faecium and 38 S. pneumoniae. The results of the susceptibility test demonstrated: 1) that in S. aureus, 100 per cent of the isolates were susceptible to vancomycin (VAN), LZ and Q/D; 93 per cent to GM; and 61 per cent to methicillin/oxacillin; 2) in S. pneumoniae, 100 per cent were susceptible to LN and GM; 87 per cent to Q/D; and 53 per cent to penicillin; 3) in E. faecalis, 99 per cent were susceptible to ampicillin; 93 per cent to LZ; 79 per cent to GM; 78.6 per cent to VAN; and 0 per cent to Q/D. Sixty eight and 66 per cent of the E. faecalis isolates were susceptible to gentamicin and streptomycin respectively; and 4) in E. faecium, 100 per cent were susceptible to LZ; 94 per cent to Q/D; 69 per cent to GM; 37.5 per cent to VAN and 20 per cent to ampicillin. In E. faecium isolates, 50 per cent and 31 per cent were susceptible to gentamicin and streptomycin, respectively. Of the vancomycin resistant enterococci, 88.9 per cent and 21 per cent of E. faecium and faecalis showed VanA phenotypic resistance, respectively...

[Laryngeal plasmacytoma]. / Plasmocitoma de laringe.

Solitary plasmocytoma is a rare presentation of plasma cell dyscrasia. About 1% od the patients can present with a extramedullary plasmocytoma; although bone presentation is the most frequent, in some cases, soft tissue can be affected. Radiotherapy remain as the election treatment. A case of primary plasmocytoma of the larynx is presented. The patient is alive after radiotherapy. Discussion about the clinical differentiation and also a review of the literature is present.

Total plasma homocysteine concentrations in Puerto Rican patients with presumptive atherosclerotic coronary disease.

BACKGROUND: In Puerto Rico, it has been established that although coronary heart disease is the leading cause of death, the population has a lower incidence of coronary disease than the continental United States. In addition, the severity of the disease is less aggressive in terms of a lower incidence of ventricular tachycardia and sudden death. A factor in the lower incidence of coronary disease in Puerto Rico could be a lower total plasma homocysteine concentration (tHcys) in our population. METHODS: We randomly measured tHcys concentrations in seventy-two Hispanic patients who were hospitalized for coronary angiography at the Cardiovascular Center of Puerto Rico and the Caribbean (UPR Division). RESULTS: The mean tHCys concentration in our patient population is similar than that reported for the Framingham study when adjusted by age (11.2 mumol/L vs. 11.8 mumol/L). In the Puerto Rican population, males had a higher tHcys concentration than females but this difference was not statistically significant (10.9 mumol/L vs. 9.4 mumol/L, p = 0.09). In addition, we did not see an increase of tHcys concentrations in diabetic patients when compared with nondiabetics (10.1 mumol/L vs. 10.3 mumol/L, p = 0.73). Neither we saw a direct correlation between tHcys concentrations and atherosclerosis as measured by coronary angiography (normal = 10.9 mumol/L, mild = 8.6 mumol/L, moderate = 10.9 mumol/L, severe = 10.5 mumol/L; ANOVA = 0.29). CONCLUSIONS: These results suggest that tHcys concentration is not a good predictor of atherosclerotic coronary disease in our patient population.

Simultaneous quantitation of intracellular zidovudine and lamivudine triphosphates in human immunodeficiency virus-infected individuals.

Highly active antiretroviral therapy (HAART) is the standard treatment for infection with human immunodeficiency virus (HIV). The most common HAART regimen consists of the combination of at least one protease inhibitor (PI) with two nucleoside reverse transcriptase inhibitors (NRTIs). Contrary to PIs, NRTIs require intracellular activation from the parent compound of their triphosphate moiety to suppress HIV replication. Simultaneous intracellular determination of two NRTI triphosphates is difficult to accomplish due to their relatively small concentrations in peripheral blood mononuclear cells (PBMCs), requiring large amounts of blood from HIV-positive patients. Recently, we described a method to determine intracellular zidovudine triphosphate (ZDV-TP) concentrations in HIV-infected patients by using solid-phase extraction and tandem mass spectrometry. The limit of quantitation (LOQ) for ZDV-TP was 0.10 pmol, and the method was successfully used for the determination of ZDV-TP in HIV-positive patients. In this study, we enhanced the aforementioned method by the simultaneous quantitation of ZDV-TP and lamivudine triphosphate (3TC-TP) in PBMCs from HIV-infected patients. The LOQ for 3TC-TP was 4.0 pmol, with an interassay coefficient of variation and an accuracy of 7 and 12%, respectively. This method was successfully applied to the simultaneous in vivo determination of the ZDV-TP and 3TC-TP pharmacokinetic profiles from HIV-infected patients receiving HAART.

Intracellular studies of the nucleoside reverse transcriptase inhibitor active metabolites: a review.

Nucleoside reverse transcriptase inhibitors (NRTIs) plasma concentrations do not correlate with clinical efficacy or toxicity. These agents need to be phosphorylated to become active against HIV-infection. Thus, the characterization of the NRTIs intracellular metabolite pharmacological parameters will provide a better understanding that could lead to the development of more rational dose regimens in the HIV-infected population. Furthermore, intracellular measurements of NRTIs may provide a better marker with respect to clinical efficacy and toxicity than plasma concentrations. Thus, in this article we review the latest information regarding the intracellular pharmacological parameters of zidovudine (ZDV) and lamivudine (3TC) active metabolites in HIV-infected patients including the results from our recent clinical studies. We will start the discussion with ZDV and 3TC clinical efficacy, followed by systemic pharmacokinetics studies. We will then discuss the in vitro and in vivo intracellular studies with particular emphasis in the method development to measure these metabolites and we will conclude with the most current data from our clinical trials.

Plasma glutathione concentrations in non-infected infants born from HIV-infected mothers: developmental profile.

Glutathione (GSH) is the primary antioxidant in humans. Oxidative cellular injury is postulated to be centrally involved in diverse processes including aging, cancer, cardiovascular disease, and Human Immunodeficiency Virus (HIV) disease progression. Normal plasma GSH concentrations have been well characterized in healthy children and adults, but not during infant development. The objectives of this study were to: a) measure plasma GSH concentrations in non-infected infants born from HIV-infected mothers, to b) assess the developmental variations with age and gender, and c) evaluate for possible associations with growth, anemia, and other maternal and infant variables. One hundred and seventy (170) plasma samples from 44 HIV-uninfected infants (birth to 18 mos.) born to HIV-infected mothers from the Women and Infant Transmission Study (Puerto Rico site) were analyzed. The total plasma GSH geometric mean concentration for all samples analyzed was 1.94 (1.06) mumoles/L. A developmental effect of age was seen with lower concentrations in younger infants (0-2 months) than in older infants 4-18 months. There was no significant effect of gender, anemia, zidovudine exposure, maternal age, maternal CD4 cell percent, or infant growth, although a trend towards increasing GSH concentration was seen with increasing weight for height z-score. These findings have multiple clinical ramifications including prediction of capacity to detoxify oxidants at different ages, and partial explanation for the increased viral loads seen in HIV-infected infants.

Field studies and cost-effectiveness analysis of vaccination with Gavac against the cattle tick Boophilus microplus.

The control of tick infestations and the transmission of tick-borne diseases remains a challenge for the cattle industry in tropical and subtropical areas of the world. Traditional control methods have been only partially successful and the parasites continue to result in significant losses for the cattle industry. Recently, vaccines containing the recombinant Boophilus microplus gut antigen Bm86 have been developed. These vaccines have been shown to control tick infestations in the field. However, extensive field studies investigating the efficacy and cost-effectiveness of vaccination have not been reported and are needed to appraise the effect of this new approach for tick control. Here is reported the results of the application of Gavac in a field trial including more than 260,000 animals in Cuba. In this study the correlation between the antibody response to vaccination and the effect on ticks fertility is determined. Physiological status of the animals was found to affect the primary response to vaccination but not the antibody titers after revaccination. A cost-effectiveness analysis showed a 60% reduction in the number acaricide treatments, together with the control of tick infestations and transmission of babesiosis, which resulted in savings of $23.4 animal-1 year-1. These results clearly demonstrate the advantage of vaccination and support the application of Gavac for tick control.

Tracheal malformation in a bicephalic Honduran milk snake (Lampropeltis hondurensis) and subsequent fatal Salmonella arizonae infection.

A bicephalic Honduran milk snake (Lampropeltis hondurensis) with tracheal duplication and malformation and Salmonella arizonae infection is described. There were atypically wide collapsed tracheal rings with necrotizing tracheitis and abundant necrotic epithelial debris and inflammatory cells obstructing the lumen in one of the duplicate tracheae. Salmonella arizonae was cultured from the malformed duplicate trachea and was considered to be the etiologic agent causing necrosis.

Renal 99Tc(m)-DMSA SPET and planar imaging: are they really the same?

Previous studies have suggested that more defects are detected on SPET than on planar DMSA images. The aim of this study was to evaluate differences between planar and SPET imaging. Sixty-four kidneys from pyelonephritic patients were studied using both techniques. An automated algorithm for reorientation and centring of the SPET images was used to minimize inter-observer variability. Reduced uptake and contour defects showed different localization on planar and SPET imaging. Coincidence of defects on both types of image was low. We also noted a dependence on defect frequency content for detectability. Image contrast played a noticeable role in the detection of defects. Differences in contrast between SPET and planar images may be responsible for the variable success in the detection of defects. Contour defects are seen more frequently on tomographic slices, whereas reduced uptake defects are seen more frequently on planar images. A difference is also noted between the cortical and calyceal zones for differently contrasted lesions. SPET and planar DMSA images can potentially provide a different diagnosis of renal lesions.

Usefulness of 99Tcm-tetrofosmin scintimammography in palpable breast tumours.

The aim of this exploratory study was to assess the potential of discriminating malignant from non-malignant lesions using 99Tcm-tetrofosmin scintimammography in the detection of palpable breast tumours. Nine patients with palpable masses were studied; seven had malignant lesions and two had non-malignant lesions. All diagnoses were established by fine-needle aspiration (FNA) biopsy cytology. Each patient received 925 MBq (25 mCi) 99Tcm-tetrosfosmin intravenously. Planar prone views were acquired in the right lateral, left lateral and anterior positions, and the axillary regions were included in the field of view. Scintimammography showed focally increased tracer uptake in seven patients with a positive FNA result. The two patients with a negative FNA result showed no increased uptake. We suggest that 99Tcm-tetrosfosmin shows promise as a radiopharmaceutical in the detection and discrimination of the nature of palpable breast tumours. Larger studies are required to confirm these findings.

Testing topographic differences between event related brain potentials by using non-parametric combinations of permutation tests.

MANOVA and repeated measures ANOVA approaches have provided evidence of a number of limitations in several event-related potential (ERP) studies due to violations of their statistical assumptions and the typically moderate size of the available sample. Alternative, computer-intensive methods based on permutation principles have recently been developed. Up to now this methodology has focused mostly on magnitude differences between scalp distributions as measured by t statistics. In this paper the scope of permutation techniques in ERP analysis was widened. A new statistic (D statistic) is introduced to compare the shapes of scalp distributions of ERPs. Additionally a general non-parametric combinatory technique is introduced to evaluate, by means of multivariate permutation tests, several time points and/or recording sites in ERP data. The methodology described here was used to test if two ERP components elicited during word-pair matching tasks to semantic or phonological incongruences had different scalp distributions.