Differential glucose and beta-hydroxybutyrate metabolism confers an intrinsic neuroprotection to the immature brain in a rat model of neonatal hypoxia ischemia

Neonatal hypoxia ischemia (HI) is the main cause of newborn mortality and morbidity. Preclinical studies have shown that the immature rat brain is more resilient to HI injury, suggesting innate mechanisms of neuroprotection. During neonatal period brain metabolism experience changes that might greatly affect the outcome of HI injury. Therefore, the aim of the present study was to investigate how changes in brain metabolism interfere with HI outcome in different stages of CNS development. For this purpose, animals were divided into 6 groups: HIP3, HIP7 and HIP11 (HI performed at postnatal days 3, 7 and 11, respectively), and their respective shams. In vivo [¹⁸F]FDG micro positron emission tomography (microPET) imaging was performed 24 and 72 h after HI, as well as ex-vivo assessments of glucose and beta-hydroxybutyrate (BHB) oxidation. At adulthood behavioral tests and histology were performed. Behavioral and histological analysis showed greater impairments in HIP11 animals, while HIP3 rats were not affected. Changes in [¹⁸F]FDG metabolism were found only in the lesion area of HIP11, where a substantial hypometabolism was detected. Furthermore, [¹⁸F]FDG hypometabolism predicted impaired cognition and worst histological outcomes at adulthood. Finally, substrate oxidation assessments showed that glucose oxidation remained unaltered and higher level of BHB oxidation found in P3 animals, suggesting a more resilient metabolism. Overall, present results show [¹⁸F]FDG microPET predicts long-term injury outcome and suggests that higher BHB utilization is one of the mechanisms that confer the intrinsic neuroprotection to the immature brain and should be explored as a therapeutic target for treatment of HI.

Flavonoid Rutin Alters the Viability and Function of Mitogen-Stimulated Splenocytes and Thymocytes Compared with Non Stimulated Cells

Rutin is a flavonoid obtained from Dimorphandra mollis (Benth.), a medicinal Brazilian plant used as antioxidative, antihemorrhagic, and blood vessel protector. The present study has examined its effects on the viability and function of immune system cells in vitro. Rat spleen and thymus cells were cultured with 10 nM, 1 microM, and 10 microM of the drug in the presence or absence of PWM, LPS, or ConA mitogens. Cellular proliferation was analyzed by H(3)-thymidin uptake and IFN-gamma and IL-10 were measured by ELISA after 48 and 72 hr. Viability was measured by flow cytometry using Annexin V and PI after 24 and 48 hr. The flavonoid rutin inhibited splenocytes and thymocytes proliferation under ConA stimulation observed by an increase on apoptosis levels of thymocytes stimulated with PWM in 24 hr and on splenocytes stimulated with PWM in 48 hr. Function studies showed a decrease on IFN-gamma production by splenocytes and thymocytes stimulated with PWM or ConA. Spleen cells cultured with LPS and rutin showed a decrease on apoptosis after 24 hr and an increase on the IL-10 levels after 48 hr. There was no significant variation on the necrosis rate, viability, and function of cells treated with rutin in the absence of mitogenic stimulus.

[New geographical distribution of Triatoma deaneorum Galvão, Souza & Lima 1967, new designation for Triatoma deanei (Hemiptera, Reduviidae)]

Authors extend the geographical distribution of Triatoma deaneorum Galvão, Souza & Lima, 1967, new designation for Triatoma deanei, based on a specimen recently found in Chapada dos Guimarães, near to Cuiabá, Mato Grosso, Brazil. The new designation is based on the International Code of Zoological Nomenclature.

[Influence of temperature and humidity on the nymphal development of Rhodnius robustus]

OBJECTIVE

To assess the significant differences in the nymphal development of the Rhodnius robustus Larrousse, 1927 under different temperatures and humidity conditions. This is a species found in the northern region of Brazil (states of Acre, Amazonas, and Pará), Colombia, Equator, Peru and Venezuela.

METHODS

Three groups of triatominae were kept under the following laboratory conditions: 33/40 (33+1 degree C and 40+/-5% of relative humidity - RH), 33/70 (33+/-1 degree C and 70+/-5% RH), and 28/70 (28+/-1 degree C and 70+/-5% RH). The incubation period of the eggs, developmental time of each stage, mortality percentage, number of bloodmeals, and the total amount of time from the egg hatching to adult ecdysis were observed.

RESULTS

The shortest average time of nymphal development was observed in the 28/70 group, with following averages: 14.4, 17.3, 20.3, 22.8, and 40. Significant differences were observed in the embryonic development between the groups (p<0.01). For all groups, the number of bloodmeals had a gradual increase near the adult phase, except for the 3rd instar of the 33/70 group. The smallest mortality percentages were seen in the 28/70 group.

CONCLUSIONS

High temperatures, regardless of the humidity, can accelerate the biological development cycle of R. robustus. However, these temperatures can impair the colonies' survival, preventing their maintenance in the laboratory.

Feeding patterns of Triatoma vitticeps in the State of Rio de Janeiro, Brazil

OBJECTIVE

Feeding patterns of triatomines have contributed to elucidate its biology. Triatoma vitticeps, naturally infected with T. cruzi, has been found in domiciles. Its behavior and epidemiological patterns were investigated.

METHODS

One-hundred and twenty two specimens of T. vitticeps were captured from February 1989 to April 1993 in two areas of Triunfo municipality, a subdistrict of Santa Maria Madalena municipal district, State of Rio de Janeiro, Brazil. The insects were dissected and their intestinal contents were removed and tested. It was used antisera from: man, cow, horse, dog, pig, armadillo, opossum, rodent, and bird.

RESULTS

From the total analyzed, 79 were positive and 43 were negative to the nine antisera tested: armadillo (30.3%) > human and pig (13.1%) > bird and dog (11.5%) > horse (5.7%) > opossum (4.9%) > rodent (4. 1%) > cow (3.3%). Blood meals ranged from 0 to 4 and 6 in the following distribution: 0 = 25.41%; 1 = 45.08%; 2 = 10.66%; 3 = 6. 56%; 4 = 1.64%, and 6 = 0.82%. Nine of the 122 insects captured were not examined, 74 (65.54%) were positive for T. cruzi infection and 39 (34.51%) were negative.

CONCLUSIONS

These results identified the T. vitticeps as being a sylvatic species and trypanosomiasis as being an enzootic disease. Epidemiological vigilance will be important to provide more information regarding the behavior of the species

[Identification of food sources of Anopheles aquasalis (Diptera: Culicidae) by precipitin test in the State of Rio de Janeiro, Brazil]

Anopheles aquasalis has shown local variations in blood-host preference in Brazil: it seems to be anthropophilic in the northeast and zoophilic or opportunistic in the Amazon and other regions. A study was carried out in Guapimirim county, State of Rio de Janeiro, from May to November 1992, for the purpose of identifying the blood meal source of this anopheline by capillary tube precipitin test. A total of 1,366 females were captured at natural resting-places, 725 of which were blood-fed. The gut content of 473 blood fed females reacted to the antisera used (human, cow, horse, pig, dog and chicken). The majority of the females-356 (75.3%)-had blood from only one source. A substantial bovine preference was observed-52.2% had fed on cows, 29.8% on horses, 10.7% on pigs, 4.5% on chickens and 1.7% on dogs, but only few had fed on man (1.1%) and none on rats. On the other hand, 24.7% of the females had fed on more than one host, mainly on cows and horses. It was assumed that An. aquasalis is zoophilic in southeastern Brazil, feeding on a wide variety of animals, the cow being the primary host.