Aspects of leaf anatomy of kudzu (Pueraria lobata, Leguminosae-Faboideae) related to water and energy balance

Kudzu is a cover crop that has escaped cultivation in some subtropical and warm temperate regions. Kudzu has previously demonstrated broad intraspecific physiological plasticity while colonizing new environments. The objective of this paper was to investigate characteristics of kudzu leaflet anatomy that might contribute to its successful growth in climatically distinct environments, and to escape cultivation as well. Fresh and fixed leaflet strips of field-grown plants were analyzed. The lower epidermis of kudzu showed a higher frequency of stomata (147 ± 19 stomata mm-2) than the upper epidermis (26 ± 17 stomata mm-2). The average number of trichomes per square milimeter was 8 for both the upper and the lower epidermis. The average trichome length was 410 ± 200 mum for the upper epidermis and 460 ± 190 mum for the lower epidermis. Cuticle thickness was not considerably different between lower and upper epidermis. The leaflet blade consisted basically of two layers (upper and lower) of unicellular epidermis, two layers of palisade parenchyma and one layer of spongy parenchyma. One layer of paraveinal mesophyll was found between palisade and spongy parenchyma. In conclusion, leaflets of kudzu present anatomical characteristics that might contribute to the broad physiological plasticity shown by kudzu.

Physiological analysis of leaf senescence of two rice cultivars with different yield potential

The objective of this work was to evaluate the physiological changes that occur in different leaves during the early and late grain-filling stages of two rice genotypes (Oryza sativa subsp. indica , BRS Pelota cultivar, and O. sativa subsp. japonica , BRS Firmeza cultivar), which present differences in grain yield potential. The plants were cultivated in greenhouse. Pigment content, chlorophyll fluorescence, electron transport and oxygen evolution rate were determined in the grain-filling stage, from the first to the forth leaf (top to bottom). Pigment content, photochemical efficiency of photosystem II and electron transport decreased significantly according to the position of leaves in 'BRS Pelota'. The BRS Firmeza cultivar shows higher pigment content and higher activity of the photosynthetic apparatus in comparison to 'BRS Pelota' during the grain-filling stage.

Influence of leaf retention on cutting propagation of Lavandula dentata L.

Vegetative propagation of lavender offers several advantages over sexual propagation, among them crop homogeneity and yield of higher quality essential oil. However, Lavandula species have been propagated mostly by seeds and are said to be recalcitrant to rooting when propagated by cuttings. During cutting propagation, one of the important variables that influence the rooting capacity of cuttings is the leaf retention. The objective of this work was to evaluate the influence of leaf retention on rooting of L. dentata cuttings. Apical cuttings of L. dentata of 10 cm in length, keeping approximately 1/3, 1/2 or 2/3 of their leaves were planted in commercial substrate Plantmax HT® under intermittent mist. After two months, averages of root number, length of the longest root, root fresh and dry weights, and the survival percentage were evaluated. Root length and fresh weight were statistically greater with 2/3 of leaf retention and when fewer leaves were kept on the cuttings, lower means of root dry weight was observed. Under the conditions applied in this study, greater leaf retention was better for rooting of L. dentata cuttings.

The effect of leaf area reduction on corn plants during the reproduction phase

Reduction in leaf area in corn plants during reproduction changes physiological metabolism and consequently the accumulation of dry matter in grains. The aim of this work was to study changes in agronomic characteristics caused by defoliation in corn during the reproduction phase. The experiment was carried out in Uberlândia, Minas Gerais state, in the agricultural year 2007/2008. The experiment was arranged in a randomized block design, consisting of seven treatments: control without defoliation, removal of two apical leaves, removal of four apical leaves, removal of all leaves above spike, removal of four intermediate leaves, removal of all leaves below spike, and removal of all plant leaves, with five repetitions. The genotype used for the evaluations was hybrid NB 7376. Defoliation was carried out when plants were at the growth stage R2. The variables assessed were: yield, density of spikes and corncobs, root resistance and stem integrity. When all leaves above the spike were removed, grain yield was reduced by 20%. Corncob density, stem integrity and root resistance to uprooting were also affected. Spike density was only affected when all plant leaves were removed. The leaf area remaining physiologically active above the spike was found to be most efficient in terms of grain yield.

A theoretical model of the evolution of virulence in sexually transmitted HIV/AIDS

INTRODUCTION: The evolution of virulence in host-parasite relationships has been the subject of several publications. In the case of HIV virulence, some authors suggest that the evolution of HIV virulence correlates with the rate of acquisition of new sexual partners. In contrast some other authors argue that the level of HIV virulence is independent of the sexual activity of the host population. METHODS: Provide a mathematical model for the study of the potential influence of human sexual behaviour on the evolution of virulence of HIV is provided. RESULTS: The results indicated that, when the probability of acquisition of infection is a function both of the sexual activity and of the virulence level of HIV strains, the evolution of HIV virulence correlates positively with the rate of acquisition of new sexual partners. CONCLUSION: It is concluded that in the case of a host population with a low (high) rate of exchange of sexual partners the evolution of HIV virulence is such that the less (more) virulent strain prevails.

Evolution of schistosomiasis in an hyperendemic area of the Minas Gerais state: two cross-sectional studies

Two cross-sectional studies on schistosomiasis mansoni were done in Comercinho, Minas Gerais (Brazil), at an interval of 7 years. In 1974 and 1981 feces examinations (KATO-KATZ method) were done in 89 and 90% of the population (about 1,500 inhabitants) and clinical examinations were done in 78 and 92% of the patients who excreted Schistosoma mansoni eggs in the feces, respectively. The rate of infection by S. mansoni did not change (69.9% in 1974 and 70.4% in 1981), but the geometrical mean of eggs per gram of feces (431 ± 4 and 334 ± 4, respectively) and the rate of splenomegaly (11 and 7%, respectively) decreased significantly in 1981, when compared to 1974. This reduction was observed only in the central zones of the town (zones 1-2) where the rate of dwellings with piped water increased from 17 to 44%. In the surroundings (zones 3-4), where the proportion of houses with piped water did not change significantly between 1974 (10%) and 1981 (7%), the geometrical mean of S. mansoni eggs and the rate of splenomegaly did not change either.

Evolution of subpatent parasitaemia in Trypanosoma cruzi chronically infected mice with the help of a cyclophosphamide amplification transfer assay

We have evaluated the sensitivity of the classical blood subinoculation method, modified through cyclophosphamide treatment of transferred mice, for the detection of occult parasitaemias in Trypanosoma cruzi chronically infected mice. Besides its simplicity, the method was shown to be highly sensitive for both the "chronic" phase parasites (99% of chronic cases were shown to harbour occult parasitaemias) and for the acute phase parasites (T. cruzi could be detected in 53.8% of animals transferred with one Y strain parasite and in 20% of animals transferred with one CL strain parasite). Using acute phase bloodforms, the assay proved to be more sensitive than conventional subinoculation when dealing with the CL, but not the Y strain of the parasite. With the help of this parasite detection tool, we have studied during a one year period, the evolution of subpatent parasitaemias in a group of mice which survived through chemotherapy from lethal acute phase of T. cruzi infection. Cyclophosphamide transfer assay revealed occult parasitaemias in 100% of the chronic animals, nevertheless, continuous and discontinuous patterns of positivity were observed.

Evolution of IgG antibody response against Toxoplasma gondii tissue cyst in acute and chronic human infections

The recognition profile of the tissue cysts antigens by IgG antibodies was studied during acute and chronic human toxoplasmic infection. Thus the IgG response against Toxoplasma gondii was investigated by immunoblotting in two patients accidentally infected with the RH strain as well as in group of naturally infected patients at acute and chronic phase. There was an overall coincidence of molecular mass among antigens of tachyzoites and tissue cysts recognized by these sera, however, they appear not to be the same molecules. The response against tissue cysts starts early during acute infection, and the reactivity of antibodies is strong against a wide range of antigens. Six bands (between 82 and 151 kDa) were exclusively recognized by chronic phase sera but only the 132 kDa band was positive in more than 50% of the sera analysed. A mixture of these antigens could be used to discriminate between the two infection phases. The most important antigens recognized by the acute and the chronic phase sera were 4 clusters in the ranges 20-24 kDa, 34-39 kDa, 58-80 kDa and 105-130 kDa as well as two additional antigens of 18 and 29 kDa. Both accidentally infected patients and some of the naturally infected patients showed a weak specific response against tissue cyst antigens.

Clinical characteristics and evolution of syphilis in 24 HIV+ individuals in Rio de Janeiro, Brazil

A total of 24 patients with syphilis and HIV infection were treated from January 1997 to March 2003 at the Infectious Dermatology Outpatient Clinic of the Evandro Chagas Clinical Research Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil. The caseload consisted of 20 males (83.3%) and four females (16.7%), with a mean age of 38.04 years and mean T CD4+ count of 389.5 cells/mL. Syphilis was diagnosed as secondary in 16 (62.5%) patients, late latent in eight (33.3%), and tertiary in one (4.2%). Manifestations of secondary syphilis were palmar and plantar erythematopapulous cutaneous lesions in nine (37.5%), papulous exanthema in four (16.7%), patchy alopecia in 3 (12.5%) and osteochondritis in one patient (4.2%). Tertiary syphilis was characterized by verrucous lesions. Neurosyphilis was diagnosed in four patients (16.7%), with headache as the only manifestation in two patients. Drugs used in treatment included benzathine penicillin, ceftriaxone, erythromycin, and crystalline penicillin. Cure was achieved in 18 patients (75%). Five patients (20.8%) were retreated, three of whom presented a history of re-exposure. This study confirms the importance of establishing the diagnosis of neurosyphilis in patients with HIV infection, in addition to performing follow-up on treatment for syphilis.

EVOLUTION OF PATIENTS WITH AIDS AFTER cART: CLINICAL AND LABORATORY EVOLUTION OF PATIENTS WITH AIDS AFTER 48 WEEKS OF ANTIRETROVIRAL TREATMENT

SUMMARY Combination Antiretroviral Therapy (cART) aims to inhibit viral replication, delay immunodeficiency progression and improve survival in AIDS patients. The objective of this study was to compare two different schemes of cART, based on plasma viral load (VL) and CD4+ T lymphocyte count, during 48 weeks of treatment. For this purpose, 472 medical charts of a Specialized Outpatient Service were reviewed from 1998 to 2005. Out of these, 58 AIDS patients who had received a triple drug scheme as the initial treatment were included in the study and two groups were formed: Group 1 (G1): 47 individuals treated with two nucleoside reverse-transcriptase inhibitors (NRTI) and one non-nucleoside reverse-transcriptase inhibitor; Group 2 (G2): 11 patients treated with two NRTI and one protease inhibitor. In G1 and G2, 53.2% and 81.8% respectively were patients with an AIDS-defining disease. The T CD4+ lymphocyte count increased progressively up until the 24th week of treatment in all patients, while VL became undetectable in 68.1% of G1 and in 63.6% of G2. The study concluded that the evolutions of laboratory tests were similar in the two treatment groups and that both presented a favorable clinical evolution.

Evolution of sarcoma 180 (ascitic tumor) in mice infected with Schistosoma mansoni

Mice infected with 60 cercariae of Schistosoma mansoni were more resistant to the sarcoma 180 ascites tumor. Tumor inoculation was performed 50 days after schistosoma infection and the animals were observed and weighed at 48 hours intervals for development and progression of malignancy. In infected mice the weight gain (ascites formation) started later and was shorter than in uninfected Controls. Also, the number of tumor cells into the peritoneal cavity 72h after tumor implantation was shorter in infected group than incontrols. This in creased resistance against a transplantable tumor probably is related to the effect of endotoxin on tumoricidal activity of macrophages activated by the infection. The immunodepression induced by Schistosoma mansoni infection enhances the proliferation of endogenous bacteria increasing the amount of endotoxin absorbed from the gut.

Clinical and laboratory findings related to a favorable evolution of hantavirus pulmonary syndrome

The medical records of 27 patients with hantavirus pulmonary syndrome were analyzed according to the need for invasive mechanical ventilation in relation to the following data up on hospital admission: age, gender, fever, cough, dyspnea, systolic arterial blood pressure, heart rate, levels of hemoglobin, hematocrit, leukocytes, lymphocytes, platelets, creatinine and arterial blood gases. The volume infused during the first 24 hours after admission, the use of inotropic agents, the use of corticosteroids and the patient outcomes were also evaluated. A favorable outcome was related to systolic blood pressure³ 100mmHg, heart rate lower than 100 beats per minute, creatinine below 1.6mg/dl, arterial blood pH³ 7.35, bicarbonate higher than 15mEq/dl, oxygen saturation higher than 84.1%, lower rehydration volume in the first 24 hours of hospitalization and no use of inotropic agents. Absence of clinical and laboratory signs of circulatory shock up on admission was associated with a favorable outcome of the patients.

Evolution of coauthorship networks: worldwide scientific production on leishmaniasis

Introduction Collaboration is one of the defining features of contemporary scientific research, and it is particularly important with regard to neglected diseases that primarily affect developing countries. Methods The present study has identified publications on leishmaniasis in the Medline database from 1945 to 2010, analyzing them according to bibliometric indicators and statistics from social network analysis. Examining aspects such as scientific production, diachronic evolution, and collaboration and configuration of the research groups in the field, we have considered the different types of Leishmania studied and the institutional affiliation and nationality of the authors. Results Seven-hundred and thirty-five authors participate in 154 prominent research clusters or groups. Although the most predominant and consolidated collaborations are characterized by members from the same country studying the same type of Leishmania, there are also notable links between authors from different countries or who study different clinical strains of the disease. Brazil took the lead in this research, with numerous Brazilian researchers heading different clusters in the center of the collaboration network. Investigators from the USA, India, and European countries, such as France, Spain, the United Kingdom, and Italy, also stand out within the network. Conclusions Research should be fostered in countries such as Bangladesh, Nepal, Sudan, and Ethiopia, where there is a high prevalence of different forms of the disease but limited research development with reference authors integrated into the collaboration networks.

In vitro antifungal activities of leaf extracts of Lippia alba (Verbenaceae) against clinically important yeast species

Introduction There are few studies reporting the antifungal activities of Lippia alba extracts. Methods A broth microdilution assay was used to evaluate the antifungal effects of Lippia alba extracts against seven yeast species of Candida and Cryptococcus. The butanol fraction was investigated by gas chromatography-mass spectrometry. Results The butanol fraction showed the highest activity against Candida glabrata. The fraction also acted synergistically with itraconazole and fluconazole against C. glabrata. The dominant compounds in the butanol fraction were 2,2,5-trimethyl-3,4-hexanedione, 3,5-dimethyl-4-octanone and hexadecane. Conclusions The butanol fraction may be a good candidate in the search for new drugs from natural products with antifungal activity.

Prevalence and evolution of Mycobacterium tuberculosis infection in tuberculosis case contacts

INTRODUCTION : The tuberculin test is a diagnostic method for detecting latent tuberculosis (TB) infection, especially among disease contact cases. The objective of this study was to analyze the prevalence and evolution of Mycobacterium tuberculosis infection among TB contact cases. METHODS : A retrospective cohort study was performed in a reference center for TB. The study population consisted of 2,425 patients who underwent a tuberculin test from 2003 to 2010 and whose results indicated contact with individuals with TB. The data were collected from the registry book of the tuberculin tests, patient files and the Information System Records of Notification Grievance. To verify the evolution of TB, case records through September 2014 were consulted. Data were analyzed using the Statistical Package for the Social Sciences (SPSS). In all hypothesis tests, a significance level of 0.05 was used. RESULTS : From the studied sample, 435 (17.9%) contacts did not return for reading. Among the 1,990 contacts that completed the test, the prevalence of latent TB infection was 35.4%. Of these positive cases, 50.6% were referred to treatment; the dropout rate was 42.5%. Among all of the contacts, the TB prevalence was 1.8%, from which 13.2% abandoned treatment. CONCLUSIONS : The collected data indicate the need for more effective public policies to improve TB control, including administering tests that do not require a return visit for reading, enhancing contact tracing and encouraging actions that reinforce full treatment adherence.