Pollen Types Used by the Native Stingless Bee, Tetragonisca angustula (Latreille), in an Amazon-Chiquitano Transitional Forest of Bolivia.

Samples of corbicular and stored pollen gathered by Tetragonisca angustula (Latreille, 1811) in an Amazon-Chiquitano transitional forest during the dry season were analyzed. The pollen spectrum was established as well as the dynamics of the relationship between the stingless bee and the surrounding flora. Pollen samples obtained from three rational hives were subjected to acetolysis and 55 pollen types were identified, the most frequent being from Anadenanthera (Fabaceae), Chenopodiaceae, and Dydimopanax (Araliaceae). Significant differences in pollen families used between hives along the months of collection were found in stored pollen and non-significant differences in corbicular pollen. Mean values of alpha diversity (H') showed T. angustula as a generalist while beta diversity qualitatively showed that pollen composition was similar between two hives both of which differed from the third hive. Pollen types in corbicular and stored pollen were in general related with richness of flowering plants in the foraging area; the pollen offer was less diverse than the pollen collected, and a trend to prefer the collection of pollen from the most abundant flowering species could be discerned. T. angustula showed polylectic feeding habits and a capacity to adapt to food availability.

Characterization and distribution of tomato yellow margin leaf curl virus, a begomovirus from Venezuela.

A begomovirus causing mottling and leaf deformation in tomato from the State of Mérida was cloned and sequenced. The virus has a bipartite genome comprised of a DNA-A (2,572 nucleotides) and a DNA-B (2,543 nucleotides) with a genome organization typical of New World begomoviruses. Both components share a common region of 115 nucleotides with 98 % sequence identity. Phylogenetic analysis indicated that while no virus sequences were closely related, the A component was distantly related to those of two other tomato-infecting viruses, tomato leaf deformation virus and Merremia mosaic virus; and the DNA-B, to those of pepper huasteco yellow vein virus and Rhynchosia golden mosaic Yucatan virus. The DNA-A and DNA-B sequences were submitted to GenBank (accession no. AY508993 and AY508994, respectively) and later accepted by the International Committee on Taxonomy of Viruses as the genome of a member of a unique virus species with the name Tomato yellow margin leaf curl virus (TYMLCV). Tomato (Solanum lycopersicum L. 'Fl. Lanai') plants inoculated with cloned TYMLCV DNA-A and DNA-B became systemically infected and showed chlorotic margins and leaf curling. The distribution of TYMLCV in tomato-producing states in Venezuela was determined by nucleic acid spot hybridization analysis of 334 tomato leaf samples collected from ten states using a TYMLCV-specific probe and confirmed by PCR and sequencing of the PCR fragment. TYMLCV was detected in samples from the states of Aragua, Guárico, and Mérida, suggesting that TYMLCV is widely distributed in Venezuela.

Piracetam-induced changes on the brainstem auditory response in anesthetized juvenile rhesus monkeys (Macaca mulatta). Report of two clinical cases.

BACKGROUND: We describe two clinical cases and examine the effects of piracetam on the brainstem auditory response in infantile female rhesus monkeys (Macaca mulatta). RESULTS: We found that the interwave intervals show a greater reduction in a 3-year-old rhesus monkey compared to a 1-year-old rhesus monkey. DISCUSSION: In this report, we discuss the significance of these observations.

The selective inhibition of the D1 dopamine receptor results in an increase of metabolized dopamine in the rat striatum.

Our aim was to study the specific role of the postsynaptic D(1) receptors on dopaminergic response and analyze the metabolized dopamine (DA) in the rat striatum. We used male Wistar rats to evaluate the effects of different doses of a D(1) agonist (SKF-38393) and a D(1) antagonist (SCH-23390), and their co-administration. The levels of DA and L-3, 4-dihydroxyphenylacetic acid (DOPAC) were measured using high performance liquid chromatography. The systemic injection of SKF-38393 alone at 1, 5 and 10 mg/kg did not alter the DA and DOPAC levels or the DOPAC/DA ratio. In contrast, injection of SCH-23390 alone at 0.25, 0.5 and 1 mg/kg significantly increased the DA and DOPAC levels, as well as the DOPAC/DA ratio, compared with the respective control groups. The co-administration of SCH-23390+SKF-38393 did not alter the DA or DOPAC levels, but it did significantly inhibit the SCH-23390-induced increase of the DA and DOPAC levels. The SCH-23390+SKF-38393 and the SCH-23390-only groups showed an increase in the DOPAC/DA ratio. The co-administration of SCH-23390+PARGYLINE significantly decreased the DOPAC levels and the DOPAC/DA ratio compared with the control and SCH-23390 groups. Taken together, our results showed that selective inhibition with SCH-23390 produced an increase in metabolized DA via striatal monoamine oxidase. These findings also contribute to the understanding of the role of postsynaptic D(1) receptors in the long-loop negative feedback system in the rat striatum.

Detection of hantaviruses in Brazilian rodents by SYBR-Green-based real-time RT-PCR.

Current knowledge of the pathogenic hantavirus indicates that wild rodents are its primary natural reservoir. Specific primers to detect the presence of viral genomes were developed using an SYBR-Green-based real-time RT-PCR protocol. One hundred sixty-four rodents native to the Atlantic Forest biome were captured in São Paulo State, Brazil, and their tissues were tested. The presence of hantavirus RNA was detected in sixteen rodents: three specimens of Akodon montensis, three of Akodon cursor, two of Necromys lasiurus, one of Juliomys sp., one of Thaptomys nigrita, five of Oligoryzomys nigripes, and one of Oryzomys sp. This SYBR Green real-time RT-PCR method for detection of hantavirus may be useful for surveying hantaviruses in Brazil.

[Paradigm of negative feedback via long-loop in the striatal dopamine release modulation in the rat]. / Paradigma de retroalimentacion negativa via circuito largo en la modulacion de la liberacion de dopamina en el estriado dorsal de la rata.

INTRODUCTION: The basal ganglia include the striatum, globus pallidus, the substantia nigra pars compacta and pars reticulata. The striatum receives afferent input from the substantia nigra pars compacta. The principal neurons of the striatum are medium spiny neurons, that express high levels of D1 and D2 receptors. AIMS: This review deals about the aspects underlying to the negative feedback via long-loop in the striatal dopamine release modulation in the rat. Also, the motor function in dopamine receptor knock-out mice is discussed. DEVELOPMENT AND CONCLUSIONS: The intrastriatal infusion and systemic injection of dopamine receptor agonists and antagonists may regulate the striatal dopamine release and induce changes in motor function. Disruption of the D1 and D2 gene shown that the motor function is controlled by D1 and D2 receptors. The study of the long-loop negative feedback may contribute to our understanding in the physiology and dysfunction of basal ganglia.

[Evaluation of the motor behavior in rats with cortical ablation]. / Caracterizacion de la conducta motora en ratas con ablacion cortical.

INTRODUCTION: The cortical ablation has been used as an experimental model in order to study the basic mechanisms of functional recovery. However, there is not data concerning to the injury effects on the motor and somatosensorial behavioral manifestations that allow us to categorize such sequels as a hemiplegic model. MATERIALS AND METHODS: We used 35 male Wistar rats (280-300 g) allocated in two groups: control (n = 17) and brain injured by cortical ablation (n = 18). Previously trained, basal recordings of the footprint and motor and somatosensorial assessment were performed in the rats before surgery. The behavioral tests were performed again 6 hours after surgery and the spontaneous ambulatory activity was also evaluated. RESULTS AND CONCLUSIONS: It was observed a decrease in the stride's length and an increase in the stride's angle and in the motor deficit, while the somatosensorial assessment and spontaneous ambulatory activity were not affected. These findings are discussed in function of the motor features of the hemiparetic sequels in humans.

Kidney involvement in Takayasu arteritis.

OBJECTIVE: To evaluate whether the presence of glomerulonephritis is or is not associated with the extent of arterial wall inflammatory cell infiltrate in Takayasu arthritis (TA). METHODS: Retrospective chart and pathology review of large artery and kidney specimens of TA autopsy cases. Kidney specimens were classified, according to their histopathological findings, in those with specific glomerular entities and those with non-specific, ischemic and/or hypertensive, glomerular changes. A control group of autopsy kidney specimens was utilized for comparison. Morphometric analysis was used to assess the extent of the arterial inflammatory infiltrates; results were compared among the different groups with kidney lesions. RESULTS: We included 25 kidney specimens from 25 autopsies. Specific glomerular entities were present in 14 specimens; 10 (40%) were classified as diffuse mesangial proliferative glomerulonephritis (DMPG [Group A]), and 4 (16%) as other associated glomerulopathies (Group B). Non-specific changes were observed in 11 (44%) specimens (Group C). The arterial inflammatory infiltrate proportion was 9.4 % for group A, 1.4% for group B, and 2.7% for group C. Furthermore, a larger proportion of vascular inflammation was confirmed for group A when compared with the other groups (p<0.05). Group A patients were younger than those in groups B and C (p<0.005) and exhibited shorter disease duration. CONCLUSION: The presence of DMPG was associated with a larger extent of vascular inflammatory cell infiltrate, suggesting a relationship between both phenomena.

Amuchina 10% solution, safe antiseptic for preventing infections of exit-site of Tenckhoff catheters, in the pediatric population of a dialysis program.

Although, decreasing in incidence with the disconnection systems, the first complication is still peritonitis in patients with chronic renal failure and the second is infection of Tenckhoff catheter exit-site. All efforts made to diminish the frequency of exit-site infection lower the possibility of peritonitis. The pediatric population is well-known to have a major risk of infectious complications, and making easy and safe the care of the exit-site will prevent the peritonitis that follows. The aim of the study was to evaluate the efficacy of the Amuchina 10% solution vs. pH neutral soap in children with chronic renal failure, on preventing exit-site infection. There were 60 patients who were assigned randomly to one of two groups. One group used Amuchina 10% solution for the daily cleaning of the exit-site, and the other used pH neutral soap, with 14 months of follow-up. Before the study they have to be free of infection for at least 30 days. All were taught by the same nurse how to clean their exit-site. Groups were almost identical in years, sex, and time on dialysis. We had nine infections in the soap group and none in the Amuchina 10% solution group, with an OR: 17 (p = 0.004). From these nine infections, the bacteria isolated were: 4 (13%) were caused by Pseudomona aeruginosa, 1 (3.3%) by Staphylococcus aureus, coagulase-positive staphylococci in 2 (6.6%) and Serratia marcensens in 1 (3.3%). In conclusion, Amuchina 10% solution is effective in preventing infection on the exit-site, without any secondary topical reaction.

Detection and Variability of Begomoviruses in Tomato from the Andean States of Venezuela.

The three Andean states of Mérida, Táchira, and Trujillo in Venezuela produce tomatoes (Lycopersicon esculentum) year-round with a high frequency of virus-like symptoms. Polymerase chain reaction amplification using degenerate primers detected begomoviruses in 18% of leaf samples collected from tomato plants showing virus-like symptoms in commercial fields in these states between 1993 and 1994. A comparison of the sequences of the amplified DNA products revealed a diversity of begomovirus sequences in tomato plants from this region. Partial A component sequences (approximately 1,100 bp) clustered in four groups based on BLAST, GAP, phylogenetic analyses of the nucleic acid sequences, and comparisons of iteron sequences with known begomoviruses. Two groups of sequences were closely related to Potato yellow mosaic virus-Venezuela strain tomato and Tomato Venezuela virus, respectively, begomoviruses previously reported from other Venezuelan states. The other two groups of sequences appear to belong to two new begomovirus species.

Population data for 15 loci (Identifiler Kit) in a sample from the Valley of Mexico.

We analyzed 242 individuals from the Valley of Mexico, including the larger and more cosmopolitan city of this country. They were PCR-typed for 15 STR loci with the AmpFlSTR Identifiler PCR Amplification Kit (Applied Biosystems). Allele frequencies for each STR were estimated and compared to previous reports. Genotype distribution by locus and by two-loci combination was in agreement with Hardy-Weinberg expectations for all fifteen STRs. This STR system in Mexican-mestizos presented a combined probability of exclusion (PE) and discrimination (PD) longer than 99.999%, respectively.

Comparison of nixtamalization and extrusion processes for a reduction in aflatoxin content.

Traditional nixtamalization and an extrusion method for making the dough (masa) for corn tortillas that requires using lime and hydrogen peroxide were evaluated for the detoxification of aflatoxins. The traditional nixtamalization process reduced levels of aflatoxin B(1) (AFB(1)) by 94%, aflatoxin M(1) (AFM(1)) by 90% and aflatoxin B(1)-8,9-dihydrodiol (AFB(1)-dihydrodiol) by 93%. The extrusion process reduced levels of AFB(1) by 46%, AFM(1) by 20% and AFB(1)-dihydrodiol by 53%. Extrusion treatments with 0, 0.3 and 0.5% lime reduced AFB(1) levels by 46, 74 and 85%, respectively. The inactivation of AFB(1), AFM(1) and AFB(1)-dihydrodiol in the extrusion process using lime together with hydrogen peroxide showed higher elimination of AFB(1) than treatments with lime or hydrogen peroxide alone. The extrusion process with 0.3% lime and 1.5% hydrogen peroxide was the most effective process to detoxify aflatoxins in corn tortillas, but a high level of those reagents negatively affected the taste and aroma of the corn tortilla as compared with tortillas elaborated by the traditional nixtamalization process.

IgG subclass reactivity to Trypanosoma cruzi in chronic chagasic patients.

BACKGROUND: The anti-Trypanosoma cruzi antibodies isotype profile in Chagas' disease has been studied in relation to different clinical manifestations. A high titer of IgG anti-T. cruzi antibodies is found in patients with cardiac involvement, while a high titer of IgA anti-T. cruzi antibodies is associated with digestive forms. OBJECTIVE: The aim of this work was to analyze the IgG subclass reactivity of anti-T. cruzi antibodies in patients with chronic Chagasic cardiomyopathy. METHODS: Twelve consecutive chagasic patients were analyzed for IgG subclass reactivity to a T. cruzi antigenic extract. They had a complete clinical evaluation, peripheral EKG, echocardiography, left ventriculogram, and coronariography. RESULTS: All patients came from rural areas of Mexico and had lived in endemic zones for over seven years. They presented left ventricular endsystolic dimension above 42 mm in 58% (7/12) and ejection fraction below 50% in 58% (7/12). We found that IgG1 and IgG2 anti-T. cruzi antibodies showed higher titer than IgG3 antibodies, with consistently low titer of IgG4 antibodies. Expression of the four IgG subclasses of anti-T. cruzi antibodies suggest a mixed Th1/Th2-like immune response under a probably continuous chronic antigenic stimulation. On the other hand, high levels of IgG2 anti-T. cruzi antibodies showed a tendency to be associated with severe cardiomegaly. CONCLUSIONS: Our results suggest that a mixed Th1/Th2-like immune response may take place in chronic chagasic patients under a chronic antigenic stimulation.

Orbital and periorbital infections.

Infections of the orbit and periorbital tissues are not uncommon. Trauma, skin infections, and sinusitis are frequently the underlying cause. Studies have shown changes in epidemiology and pathogens in the last decade. Although classical manifestations are usually present, atypical cases without specific signs and symptoms may confound the diagnosis. A high index of suspicion, aided by ultrasonography, computed tomography, and magnetic resonance imaging, is frequently required for an accurate diagnosis. Prompt diagnosis and treatment may lead to resolution of the infection, thus avoiding ocular sequelae. Orbital infections may spread into the globe, causing endophthalmitis. Some patients may even need an enucleation or evisceration. New materials and techniques may improve the final result of an anophthalmic socket.

Ways of coping and the health of relatives facing drug and alcohol problems in Mexico and England.

AIMS: To compare two contrasting socio-cultural groups in terms of parameters relating to the stress - coping - health model of alcohol, drugs and the family, and to test hypotheses derived from the model in each of the two groups separately. DESIGN: Cross-sectional, comparative and correlational, using standard questionnaire data, supplemented by qualitative interview data to illuminate the findings. PARTICIPANTS: One hundred close relatives, mainly partners or parents, from separate families in Mexico City, and 100 from South West England. Data sources. Coping Questionnaire (CQ), Family Environment Scale (FES), Symptom Rating Test (SRT), Semi-structured interview. FINDINGS: Mean symptom scores were high in both groups, and not significantly different. The hypothesis that relatives in Mexico City, a more collectivist culture, would show more tolerant - inactive coping was not supported, but there was support for the prediction that relatives in South West England would show more withdrawal coping. This result may be as much due to differences in poverty and social conditions as to differences in individualism - collectivism. As predicted by the stress - coping - health model, tolerant - inactive coping was correlated with symptoms, in both groups, after controlling for family conflict, but there was only limited support for a moderating role of coping. Wives of men with alcohol problems in Mexico City, and wives of men with other drug problems in South West England, reported particularly high levels of both engaged and tolerant - inactive coping. CONCLUSIONS: Tolerant - inactive coping may be bad for relatives' health: causality may be inferred but is not yet proved. Certain groups are more at risk of coping in this way. Qualitative data help understand the nature of tolerant - inactive coping and why it occurs despite the view of relatives themselves that it is counter-productive.

Anticardiolipin antibodies are not associated with rheumatic heart disease.

The aim of this study was to examine the prevalence of anticardiolipin antibodies in rheumatic valve heart disease. Serum samples of 31 consecutive patients with rheumatic heart disease and documented valve involvement, as well as six patients with acute rheumatic fever were tested for IgG anticardiolipin antibodies by a validated ELISA. No anticardiolipin antibodies were found when a cut-off point set at mean +/- 5 s.d. was applied. We can conclude that anticardiolipin antibodies are not present in rheumatic heart disease patients and, as suggested by several observations, these antibodies do not appear to have a pathogenic role in this particular disease.

Vascular endothelial growth factor and hypertrophic osteoarthropathy.

OBJECTIVE: Hypertrophic osteoarthropathy (HOA) is characterized by the coexistence of digital clubbing and periosteal proliferation of the tubular bones. Localized vascular proliferation associated with platelet/endothelial cell activation are recognized features of this syndrome. Current knowledge suggests that HOA develops from the presence in the systemic circulation of one or more growth factors that are normally inactivated in the lungs. The nature of these purported growth factors has not yet been identified. Vascular endothelial growth factor (VEGF) has several features that may fit in with the pathogenesis of HOA. The objective of our study was to measure serum and plasma levels of VEGF in different groups of patients with HOA. METHODS: We studied 24 patients with HOA; of these, in 12 the HOA was secondary to cyanotic congenital heart disease and in 7 to lung cancer, while 5 represented primary cases. As controls we studied 28 individuals without HOA; of these, 12 were apparently healthy individuals, 7 had cyanosis secondary to chronic obstructive pulmonary disease, and 9 had lung cancer. ELISA was used to measure serum and plasma levels of VEGF. RESULTS: Plasma levels of VEGF were significantly higher in the patients with primary HOA (median 46.2; range 19.4-398.8 pg/ml) and in those with lung cancer-HOA (median 75.5; range 24.6-166.7), compared to healthy controls (median 7.4; range: 0-26.1), p < 0.05. Serum VEGF levels were higher in patients with lung cancer and HOA (median 411.4; range 164.2-959.5 pg/ml) compared with lung cancer patients without HOA (median 74.5; range 13.2-205.4), p < 0.001. CONCLUSIONS: Patients with primary HOA and those with HOA and lung cancer have increased circulating levels of VEGF. This cytokine may play a role in the pathogenesis of HOA.